| Korkut I and Bayramoglu M (2018), "Selection of catalyst and reaction conditions for ultrasound assisted biodiesel production from canola oil", Renewable Energy., February, 2018. Vol. 116(A), pp. 543-551. |
| Abstract: In this study, the experimental optimization of ultrasound assisted
biodiesel production in presence of heterogeneous catalyst was investigated. Three catalysts namely; CaO, calcined dolomite and calcium diglyceroxide (CaDG) were taken into account for comparative purpose. D-optimal experimental plan was applied to obtain regression models which were subsequently used for the detection of optimum process conditions. Maximum biodiesel yields were calculated as 98.7 95.9% and 86.3% for CaO, calcined dolomite and CaDG respectively. Furthermore, supplemental experiments were conducted around optimum process conditions to test the validity of the regression models and to refine the optimum results. Finally, in the case of CaO catalyst, maximum biodiesel yield (99.4 was obtained at the following conditions; catalyst loading: 5.35% (wt.of oil), methanol/oil ratio: 7.48, ultrasonic power: 40 W, time: 150 min, and reaction temperature: 60 degrees C. (C) 2017 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Korkut2018,
author = {Korkut, Ibrahim and Bayramoglu, Mahmut},
title = {Selection of catalyst and reaction conditions for ultrasound assisted biodiesel production from canola oil},
journal = {Renewable Energy},
year = {2018},
volume = {116},
number = {A},
pages = {543--551},
doi = {10.1016/j.renene.2017.10.010}
}
|
| Aydin ES, Yucel O and Sadikoglu H (2018), "Numerical and experimental investigation of hydrogen-rich syngas production via biomass gasification", International Journal of Hydrogen Energy., January, 2018. Vol. 43(2), pp. 1105-1115. |
| Abstract: Abstract In this work, the relation between hydrogen-rich syngas production and the gasification parameters such as equivalence ratio (ER), gasification temperature and biomass moisture content were studied. Stoichiometric equilibrium model that developed during this study was used to investigate the optimum hydrogen output generated from woody biomass in a fixed bed downdraft gasifier by considering the thermodynamic equilibrium limit. The mathematical model, based on thermodynamic equilibrium is necessary to understand complicated gasification process that will contribute to obtain maximum attainable hydrogen production. The effects of different oxidizing agents on the hydrogen concentration in the product gas as well as the effect of various air-biomass, oxygen-biomass and steam-biomass ratios were investigated. For validation, the results obtained from the mathematical model were compared with the experimental data obtained from the gasifier that uses air as gasification medium. The validated mathematical model was used to represent the gasifier that uses both oxygen and air-steam mixture as the gasification medium and the theoretical results were obtained for both cases. The theoretical results clearly show that the gasification process specially ones that use the air-steam mixture as the gasification medium can be used for hydrogen production. |
BibTeX:
@article{Aydin2018,
author = {Ebubekir Siddik Aydin and Ozgun Yucel and Hasan Sadikoglu},
title = {Numerical and experimental investigation of hydrogen-rich syngas production via biomass gasification},
journal = {International Journal of Hydrogen Energy},
year = {2018},
volume = {43},
number = {2},
pages = {1105--1115},
url = {https://www.sciencedirect.com/science/article/pii/S0360319917343008},
doi = {10.1016/j.ijhydene.2017.11.013}
}
|
| Ergan BT, Bayramoğlu M and Şahin E (2017), "Regioselective nitration of phenol under continuous microwave irradiation", Journal of Microwave Power and Electromagnetic Energy., December, 2017. Vol. 51(4), pp. 314-324. Taylor & Francis. |
| Abstract: ABSTRACTThis study deals with the nitration of phenol in a multimode MW reaction system operating under continuous microwave (MW) irradiation. Reactions were carried out with two nitric acid (HNO3)/phenol molar ratios: 1.25 and 1.1, under the following conditions: applied (nominal) MW power, Pnom = 600 W, adsorbed power P = 16.0 kW dm−3, reaction temperature, TR = 68–90 °C, reaction time, t = 5–9 min, heating rate 0.1–0.25 °C s−1. At the end of the synthesis, para/ortho (p/o) isomer distribution of nitrophenol product was determined by high-pressure liquid chromatography (HPLC). Furthermore, conventional (CH) experiments were conducted also under the same conditions. Then, MW and CH methods were compared in terms of product yield and isomer distribution. According to results, yield and para-selectivity of MW-assisted synthesis were higher than the CH counterpart although the reaction temperature of the MW method was lower than that of the CH method. |
BibTeX:
@article{Ergan2017,
author = {Başak Temur Ergan and Mahmut Bayramoğlu and Elif Şahin},
title = {Regioselective nitration of phenol under continuous microwave irradiation},
journal = {Journal of Microwave Power and Electromagnetic Energy},
publisher = {Taylor & Francis},
year = {2017},
volume = {51},
number = {4},
pages = {314--324},
url = {
|
| Bolek S and Ozdemir M (2017), "Optimization of roasting conditions of microwave roasted Pistacia terebinthus beans", Lwt-food Science and Technology., December, 2017. Vol. 86, pp. 327-336. |
| Abstract: The possibility of using microwave energy as a quick and practical method for roasting of P. terebinthus beans was investigated. P. terebinthus beans were roasted at 360 W, 540 W and 720 W for 5, 11 and 17 min. A three-level two factor (3(2)) full factorial design was used to determine the effect of microwave roasting power and roasting time on physicochemical properties such as color, moisture content, density and breaking force, and sensory attributes of the P. terebinthus beans. L* value, moisture content, density and breaking force of microwave roasted P. terebinthus beans decreased with increasing the roasting power and roasting time. Dark roasted P. terebinthus beans took the highest acceptability scores in acceptability tests by the assessors. The changes in physicochemical properties and sensory attributes during microwave roasting were successfully described by the quadratic models developed and using response surface methodology (RSM). Optimum region of roasting conditions was determined by RSM in which superimposed contour plots yielded the optimal microwave roasting powers and roasting times corresponding to the dark roast. (C) 2017 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Bolek2017a,
author = {Bolek, S. and Ozdemir, M.},
title = {Optimization of roasting conditions of microwave roasted Pistacia terebinthus beans},
journal = {Lwt-food Science and Technology},
year = {2017},
volume = {86},
pages = {327--336},
doi = {10.1016/j.lwt.2017.08.017}
}
|
| Dursun B, Topac E, Alibeyli R, Ata A, Ozturk O and Demir-Cakan R (2017), "Fast microwave synthesis of SnO2@graphene/N-doped carbons as anode materials in sodium ion batteries", Journal of Alloys and Compounds., December, 2017. Vol. 728, pp. 1305-1314. |
| Abstract: Hybrid SnO2@graphene (SG) and SnO2@graphene/N-doped carbon (SGN) structures are synthesized by a fast microwave method and tested as anode materials for Na-ion batteries. In these structures, graphene not only acts as a conducting material but also as supporting material to prevent the volume expansion of the SnO2 nanoparticles. Additional N-doped carbon coating leads to improved electrochemical performances providing better electronic conductivity resulting over 423 mAh/g capacity after 180 cycles at C/5 with SGN, while SG only provides 170 mAh/g capacities. (C) 2017 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Dursun2017,
author = {Dursun, B. and Topac, E. and Alibeyli, R. and Ata, A. and Ozturk, O. and Demir-Cakan, R.},
title = {Fast microwave synthesis of SnO2@graphene/N-doped carbons as anode materials in sodium ion batteries},
journal = {Journal of Alloys and Compounds},
year = {2017},
volume = {728},
pages = {1305--1314},
doi = {10.1016/j.jallcom.2017.09.081}
}
|
| Tekin B, Sevinc S, Morcrette M and Demir-Cakan R (2017), "A New Sodium-Based Aqueous Rechargeable Battery System: The Special Case of Na0.44MnO2/Dissolved Sodium Polysulfide", Energy Technology., December, 2017. Vol. 5(12), pp. 2182-2188. |
| Abstract: Herein, the electrochemical performance of a new sodium-based aqueous rechargeable battery is demonstrated consisting of Na0.44MnO2 as cathode and dissolved sodium polysulfide (i.e., Na2S5) as anolyte. Na0.44MnO2 synthesized through a solid-state reaction method and dissolved Na2S5 anolyte are tested separately in a half-cell configuration, both giving rise to stable cycling performances. As the anode side of the desired full-cell configuration is at present dissolved in the electrolyte, the positive and negative electrodes need to be separated with an ion-selective membrane that is permeable to sodium ions and impermeable to polysulfide species. Hence, Nafion is tested as a barrier to prevent the leakage of the dissolved polysulfides. After careful tuning of the osmotic pressure inside the Nafion membrane, leakage of the dissolved polysulfide from the anode to the cathode side is eliminated, resulting in a 0.8 V average voltage, low-cost sodium-ion aqueous cell. |
BibTeX:
@article{Tekin2017,
author = {Tekin, Burak and Sevinc, Serkan and Morcrette, Mathieu and Demir-Cakan, Rezan},
title = {A New Sodium-Based Aqueous Rechargeable Battery System: The Special Case of Na0.44MnO2/Dissolved Sodium Polysulfide},
journal = {Energy Technology},
year = {2017},
volume = {5},
number = {12},
pages = {2182--2188},
url = {http://dx.doi.org/10.1002/ente.201700245},
doi = {10.1002/ente.201700245}
}
|
| Isleroglu H, Sakin-Yilmazer M, Kemerli-Kalbaran T, Uren A and Kaymak-Ertekin F (2017), "Kinetics of colour, chlorophyll, and ascorbic acid content in spinach baked in different types of oven", International Journal of Food Properties., November, 2017. Vol. 20(11), pp. 2456-2465. Taylor & Francis. |
| Abstract: ABSTRACTSpinach was baked in steam-assisted hybrid ovens, natural and forced convection ovens, and saturated steam ovens at different temperatures and baking times. The moisture content, water activity, peroxidise activity, colour, ascorbic acid, and chlorophyll content were determined for each baking time and kinetic analysis of thermal degradation of the colour, chlorophyll, and ascorbic acid were evaluated. Degradation of green colour, total chlorophyll, and ascorbic acid in spinach leaves during the baking process was considered as first order reaction kinetics and temperature dependency of degradation was described by the Arrhenius equation. Baking in steam-assisted hybrid ovens resulted in the highest rate of reaction for both colour change and chlorophyll degradation, followed by forced convection and then natural convection ovens. The existence of steam in the baking chamber resulted in an acceleration of the baking process and better ascorbic acid retention in spinach was determined by baking in steam-assisted hybrid ovens. Degradation kinetics could allow definition of optimum baking temperatures and times in different types of ovens and shorter baking times should be preferred in steam-assisted hybrid ovens if fresh appearance (high greenness) is desired. |
BibTeX:
@article{Isleroglu2017,
author = {Hilal Isleroglu and Melike Sakin-Yilmazer and Tansel Kemerli-Kalbaran and Ali Uren and Figen Kaymak-Ertekin},
title = {Kinetics of colour, chlorophyll, and ascorbic acid content in spinach baked in different types of oven},
journal = {International Journal of Food Properties},
publisher = {Taylor & Francis},
year = {2017},
volume = {20},
number = {11},
pages = {2456--2465},
url = {
|
| Bayramoglu M and Ilbay Z (2017), "Environmental aspects of direct methanol fuel cell: Experimental detection of methanol electro-oxidation products", ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY., November, 2017. Vol. 36(6), pp. 1847-1855. |
| Abstract: This study deals with the experimental investigation of compositional
changes of various liquid/gas streams during mid-term (3 h) continuous operation of an active direct methanol fuel cell (DMFC). A test system is equipped with various sensors and with sampling ports to collect liquid samples to measure off-line methanol, formaldehyde, and formic acid concentrations by means of high pressure liquid chromatography (HPLC) and UV spectroscopy. Initially, polarization study is performed to select suitable operating ranges to be considered in an experimental plan according to which runs are performed to collect process data from the system. Then, the experimental data is fitted using regression analysis for the statistical evaluation of the impacts of operating variables on the compositions of methanol tank solution and cathode gas by means of response surface plots. The cathode gas composition is further discussed in the context of methanol crossover and catalytic chemical reactions on the cathode side. Experiments show that methanol, formaldehyde, and formic acid concentrations may exceed their safe limits of exposure depending on the operating conditions. (c) 2017 American Institute of Chemical Engineers Environ Prog, 36: 1847-1855, 2017 |
BibTeX:
@article{Bayramoglu2017,
author = {Bayramoglu, Mahmut and Ilbay, Zeynep},
title = {Environmental aspects of direct methanol fuel cell: Experimental detection of methanol electro-oxidation products},
journal = {ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY},
year = {2017},
volume = {36},
number = {6},
pages = {1847--1855},
doi = {{10.1002/ep.12633}}
}
|
| Seker M, Buyuksari E, Topcu S, Babaoglu DS, Celebi D, Keskinler B and Aydiner C (2017), "Effect of pretreatment and membrane orientation on fluxes for concentration of whey with high foulants by using NH3/CO2 in forward osmosis", Bioresource Technology., November, 2017. Vol. 243, pp. 237-246. |
| Abstract: Usage of forward osmosis membrane in FO mode, in which active and support layers of the membrane were in contact with the feed and the draw solutions respectively, provided higher initial water flux (12 L/m(2) h) than the usage of membrane in PRO mode (6 L/m(2) h) having opposite orientation but fluxes approached to each other after 4 h during concentration of whey with NH3/CO2 as draw salt. High organic and inorganic foulants of whey was considered as reason for observed result in addition to lower solute resistivity. Initial water flux (8,5 L/m(2) h) was lower when pre-treatment was applied before forward osmosis process but final flux (4 L/m(2) h) was equal flux of non pre-treatment. Reduction of solute resistivity or absence of hydraulic pressure can be reasons for lower initial flux. Detection of organic carbon but absence of lactose in draw solution showed passage of molecules being different than lactose into draw solution. (C) 2017 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Seker2017,
author = {Seker, M. and Buyuksari, E. and Topcu, S. and Babaoglu, D. S. and Celebi, D. and Keskinler, B. and Aydiner, C.},
title = {Effect of pretreatment and membrane orientation on fluxes for concentration of whey with high foulants by using NH3/CO2 in forward osmosis},
journal = {Bioresource Technology},
year = {2017},
volume = {243},
pages = {237--246},
doi = {10.1016/j.biortech.2017.06.101}
}
|
| Demirkan MT, Yurukcu M, Dursun B, Demir-Cakan R and Karabacak T (2017), "Evaluation of double-layer density modulated Si thin films as Li-ion battery anodes", Materials Research Express., October, 2017. Vol. 4(10), pp. 106405. |
| Abstract: Double-layer density modulated silicon thin films which contain alternating low and high density Si film layers were fabricated by magnetron sputtering. Two different samples consisting of alternating layers of high-density/low-density and low-density/high-density Si thin film layers were investigated as anode electrodes in Li-ion batteries. Si thin film in which the terminating layer at the top is low density Si layer-quoted as low-density/high-density film (LD/HD)-exhibits better performance than Si thin film that has high density layer at the top, -quoted as high-density/low-density (HD/LD). A highly stabilized cycling performance with the specific charge capacities of 2000 mAh g(-1) at the 150th cycle at C/2 current density, and 1200 mAh g(-1) at the 240th cycle at 10 C current density were observed for the LD/HD Si anode in the presence of fluoroethylene carbonate (FEC) electrolyte additive. |
BibTeX:
@article{Demirkan2017,
author = {Demirkan, M. T. and Yurukcu, M. and Dursun, B. and Demir-Cakan, R. and Karabacak, T.},
title = {Evaluation of double-layer density modulated Si thin films as Li-ion battery anodes},
journal = {Materials Research Express},
year = {2017},
volume = {4},
number = {10},
pages = {106405},
doi = {10.1088/2053-1591/aa8f88}
}
|
| Melikoglu M (2017), "Geothermal energy in Turkey and around the World: A review of the literature and an analysis based on Turkey's Vision 2023 energy targets", Renewable & Sustainable Energy Reviews., September, 2017. Vol. 76, pp. 485-492. |
| Abstract: Turkey's geothermal energy potential suitable for electricity generation was estimated at nearly 4500 MW. In Turkey, work on power production from geothermal energy started in the second half of the 20th century. However, capacity build up and investments accelerated after 2000s. This is mostly related to Turkey's staggering economic growth in the last 10 years, which concurrently increased the country's energy demand. Also, renewable energy, especially geothermal energy, legislations passed and laws enacted in the last 10 years eased the process. The subsidies and supports to the private sector also positively affected the development of geothermal power plants. The growth of Turkey's energy market is a part of Turkey's ambitious Vision 2023 energy targets. One of the main aims of which is to produce 30% of Turkey's electricity demand in 2023 from renewable energy sources. However, geothermal energy has the smallest share (in terms of installed capacity) in the Vision 2023 energy targets set at 600 MW by the year 2023 (target, as of 2015, can be modified). This means geothermal power plants could only provide 0.5% of Turkey's installed capacity, which was estimated as 120,000 MW in the year 2023. In this study, it was pinpointed that geothermal energy installed capacity of Turkey reached to 623.9 MW at the end of 2015. This is critically important for the realisation of the Vision 2023 energy targets, and it is the first renewable energy target that has been fulfilled before 2023. Also, in this study, it was suggested to modify the Vision 2023 targets to increase the geothermal energy installed capacity to 1000 MW. By this way, the share of geothermal energy in Turkey's installed capacity of 2023 could rise to nearly 0.8%. |
BibTeX:
@article{Melikoglu2017,
author = {Melikoglu, M.},
title = {Geothermal energy in Turkey and around the World: A review of the literature and an analysis based on Turkey's Vision 2023 energy targets},
journal = {Renewable & Sustainable Energy Reviews},
year = {2017},
volume = {76},
pages = {485--492},
doi = {10.1016/j.rser.2017.03.082}
}
|
| Salihoglu O and Demir-Cakan R (2017), "Factors Affecting the Proper Functioning of a 3Ah Li-S Pouch Cell", Journal of The Electrochemical Society., September, 2017. Vol. 164(13), pp. A2948-A2955. |
| Abstract: The research on Li-S batteries is definitely progressing and superior cycling performances are achieved at the laboratory scale. Now the question is how all this great knowledge gained from the small laboratory scale experiments would be implemented into the large scale cells while still be able to outperform the Li-ion batteries readily available at the marketplace. Herein, every aspects of the manufacturing of a 3 Ah Li-S pouch cell are unveiled and discussed in details that are conclusively an undisclosed process. As expected, it is found that when the coin cell tests are adapted to the pouch cell, much pronounced problems are detected resulting much faster cell failure. Initially the pouch cell is exhibited 120 Wh/kg energy density based on the mass of the entire cell and losses its almost 85% capacity after 100 cycles. Experimentally speaking, relatively low gravimetric energy density and the short cycle life of the Li-S cells are directly linked with the lower sulfur utilization, unprotected Li metal anode as well as to the need to operate in excess of electrolyte which occupies more than 60 wt% of the entire cell imposing a great penalty in terms of energy density to the Li-S system. |
BibTeX:
@article{Salihoglu2017,
author = {Salihoglu, Omer and Demir-Cakan, Rezan},
title = {Factors Affecting the Proper Functioning of a 3Ah Li-S Pouch Cell},
journal = {Journal of The Electrochemical Society},
year = {2017},
volume = {164},
number = {13},
pages = {A2948-A2955},
url = {http://jes.ecsdl.org/content/164/13/A2948.abstract},
doi = {10.1149/2.0271713jes}
}
|
| Seker M, Buyuksari E, Topcu S, Sesli D, Celebi D, Keskinler B and Aydiner C (2017), "Effect of process parameters on flux for whey concentration with NH3/CO2 in forward osmosis", Food and Bioproducts Processing., September, 2017. Vol. 105, pp. 64-76. |
| Abstract: Increasing flow rate from 150 to 450 L/h did not change water flux but further increase to 600 L/h decreased it, which were between 2.74 and 4.1 L/m(2)h. Rising flow rate from 150 to 450 L/h enhanced final salt flux but rising flow rate to 600 L/h caused opposite effect on salt flux and maximized solute resistivity. As temperature of feed was elevated from 20 to 30 degrees C, water flux increased to 7.2 L/m(2)h but changing temperature to 35 and 40 degrees C reduced it. Salt flux was affected from process temperature in similar way as water flux was affected. Higher solute resistivity was obtained at 35 and 40 degrees C. Ascending draw solution concentration from 1 to 2 M enhanced water flux to 12 L/m(2)h but its further increase to 4 M reduced it. Salt flux did not change linearly and rose to the highest level at 2 M draw salt concentration. The highest value of solute resistivity was obtained at 3 and 4 M salt concentration. Effect of flow rate, feed temperature and salt concentration on water flux being expressed above was found similar to their effect on effective osmotic pressure difference and solute resistivity. This results show relation of water flux with effective osmotic pressure difference and solute resistivity. Carbohydrates passage from whey to draw solution was not detected but there was passage of other solubles from whey to draw solution. Flow rate of 450 L/h, process temperature of 30 degrees C and 2 M salt concentration were optimum process conditions for water flux. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. |
BibTeX:
@article{Seker2017a,
author = {Seker, M. and Buyuksari, E. and Topcu, S. and Sesli, D. and Celebi, D. and Keskinler, B. and Aydiner, C.},
title = {Effect of process parameters on flux for whey concentration with NH3/CO2 in forward osmosis},
journal = {Food and Bioproducts Processing},
year = {2017},
volume = {105},
pages = {64--76},
doi = {10.1016/j.fbp.2017.05.006}
}
|
| Yesilot S, Hacivelioglu F, Kucukkoylu S, Celik KB, Sayan G and Demir-Cakan R (2017), "Design, Synthesis, and Characterization of Polyphosphazene Bearing Stable Nitroxide Radicals as Cathode-Active Materials in Li-Ion Batteries", Macromolecular Chemistry and Physics., September, 2017. Vol. 218(17), pp. 1700051. |
| Abstract: A new synthetic strategy is developed for the synthesis of polyphosphazene bearing stable nitroxide radicals as a pendant group. The resulting material is investigated as a cathode-active material for rechargeable lithium-ion batteries that performs 80 mAh g(-1) capacities at a C/2 current density over 50 cycles. Thus, the inorganic-organic hybrid system can be proposed as an alternative cathode-active material with improved performance. |
BibTeX:
@article{Yesilot2017,
author = {Yesilot, S. and Hacivelioglu, F. and Kucukkoylu, S. and Celik, K. B. and Sayan, G. and Demir-Cakan, R.},
title = {Design, Synthesis, and Characterization of Polyphosphazene Bearing Stable Nitroxide Radicals as Cathode-Active Materials in Li-Ion Batteries},
journal = {Macromolecular Chemistry and Physics},
year = {2017},
volume = {218},
number = {17},
pages = {1700051},
doi = {10.1002/macp.201700051}
}
|
| Melikoglu M (2017), "Vision 2023: Status quo and future of biomass and coal for sustainable energy generation in Turkey", RENEWABLE & SUSTAINABLE ENERGY REVIEWS., July, 2017. Vol. 74, pp. 800-808. |
| Abstract: Detailed analysis of the literature showed that information about the
role of biomass and coal in Turkey's Vision 2023 energy targets is scarce in the published literature. Also, there is no detailed information about the potential applications of co-firing and co-gasification of biomass with coal in Turkey. Consequently, this paper was written with a global to local perspective to provide these important information. According to Turkey's Vision 2023 energy agenda installed capacity of coal power plants will increase from 15.0 to 30.0 GW, and installed capacity of biomass power plants will rise from nil to 2000 MW in 2023. In this study, it was estimated that Turkey should spent between 26.3 and 28.5 billion US$ to the capital investments of new coal power plants depending on the supply ratio from lignite or hard coal to fulfil the Vision 2023 coal target. Recently, the author estimated that Turkey should spend between 3.8 and 13.6 billion US$ to fulfil the Vision 2023 biomass energy target of 2000 MW. Thus, totalling the required coal and biomass investments to fulfil Vision 2023 targets between 30.1 and 42.1 billion US$. If everything goes according to plan and these massive investments can be financed, coal and biomass will support 25.0% and 1.7% of Turkey's electricity demand in 2023, respectively. Increased consumption of coal, mostly indigenous lignite, and biomass will decrease Turkey's foreign trade deficit based on imported energy sources. However, their increased consumption will also rise Turkey's greenhouse gas emissions. In that context, synergistic solution of co-firing and co-gasification of biomass with coal could help Turkey tackle its dependency on foreign energy sources and reduce its greenhouse gas emissions. Conditional that research and development in this field is supported both by the Turkish government and private sector. |
BibTeX:
@article{Melikoglu2017e,
author = {Melikoglu, Mehmet},
title = {Vision 2023: Status quo and future of biomass and coal for sustainable energy generation in Turkey},
journal = {RENEWABLE & SUSTAINABLE ENERGY REVIEWS},
year = {2017},
volume = {74},
pages = {800--808},
doi = {10.1016/j.rser.2017.03.005}
}
|
| Bolek S and Ozdemir M (2017), "Optimization of roasting conditions of Pistacia terebinthus in a fluidized bed roaster", Lwt-food Science and Technology., July, 2017. Vol. 80, pp. 67-75. |
| Abstract: Pistacia terebinthus fruit after roasting has a similar aroma and flavor to conventional roasted coffee beans, and it can be a promising caffeine-free alternative to coffee. P. terebinthus beans were roasted at 180 degrees C, 200 degrees C and 220 degrees C for 5, 20 and 35 min at each roasting temperature. The effects of the roasting conditions on color, moisture content, density, breaking force and sensory properties (appearance, odor, texture, flavor and overall impression) of the P. terebinthus beans were investigated using a three-level two factor (32) full factorial design. The effect of roasting temperature and roasting time on quality attributes of P. terebinthus beans roasted in a fluidized bed roaster was analyzed using response surface methodology. Quality attributes of the roasted P. terebinthus beans were significantly (p <= 0.05) affected by the roasting temperature and roasting time. Based on the superimposed contour plot, optimum region of roasting temperature and time was determined. The quadratic models developed adequately described the relationship between the factors and the responses. Dark roasted P. terebinthus beans took the highest scores in sensory tests by the panelists. (C) 2017 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Bolek2017,
author = {Bolek, S. and Ozdemir, M.},
title = {Optimization of roasting conditions of Pistacia terebinthus in a fluidized bed roaster},
journal = {Lwt-food Science and Technology},
year = {2017},
volume = {80},
pages = {67--75},
doi = {10.1016/j.lwt.2017.02.007}
}
|
| Cengiz EC, Erdol Z, Sakar B, Aslan A, Ata A, Ozturk O and Demir-Cakan R (2017), "Investigation of the Effect of Using Al2O3-Nafion Barrier on Room-Temperature Na-S Batteries", Journal of Physical Chemistry C., July, 2017. Vol. 121(28), pp. 15120-15126. |
| Abstract: Room-temperature sodium-sulfur batteries are promising battery systems because of their high theoretical capacity, high energy density, and low cost. However, their application is hindered by several issues, especially linked with the polysulfide shuttle effect. Herein, Al2O3-Nafion membrane is used to prevent migration of polysulfides from the cathode side to the anode assisting to lessen the active material loss. While Al2O3 is a very effective adsorbent to trap polysulfides anions, Nafion membrane has cation selectivity which permits migration of Na+ cations and repels polysulfide anions due to the negatively charged sulfonic groups. Thus, an increase in the performance of room-temperature sodium-sulfur batteries (RT Na-S batteries) is expected by combining their constructive effects. As a result, higher capacity retention is achieved with,similar to 250 mAh/g capacities after 100 cycles in the presence of Al2O3-Nafion membrane in contrast to the cell without any interlayer. |
BibTeX:
@article{Cengiz2017,
author = {Cengiz, E. C. and Erdol, Z. and Sakar, B. and Aslan, A. and Ata, A. and Ozturk, O. and Demir-Cakan, R.},
title = {Investigation of the Effect of Using Al2O3-Nafion Barrier on Room-Temperature Na-S Batteries},
journal = {Journal of Physical Chemistry C},
year = {2017},
volume = {121},
number = {28},
pages = {15120--15126},
doi = {10.1021/acs.jpcc.7b04711}
}
|
| Aydin ES, Yucel O and Sadikoglu H (2017), "Development of a semi-empirical equilibrium model for downdraft gasification systems", Energy., July, 2017. Vol. 130, pp. 86-98. |
| Abstract: This study proposes a stoichiometric equilibrium model (SEM) to predict the chemical composition of the syngas, yield of tar and char produced by a downdraft gasifier for various wood based fuels for different equivalence ratios (ER). Equivalence ratio is a measure of the amount of external air supplied to the gasifier and one of the crucial operating variables in biomass gasification. Global stoichiometric equilibrium approach is used to model a downdraft gasifier. In order to predict dry gas composition, three different SEM models have been developed. Those models were validated and modified through comparison with the large amount of data collected from various sources. We have introduced two correction factors for altering the equilibrium constant of methanation and the water-gas shift reaction as a function of gasification temperature, equilibrium temperature and ER. Those correction factors were obtained by comparison of the theoretical models with experimental data of downdraft gasification of woody biomass from literature-by using Levenberg-Marquadt algorithm. The modified model shows a clear enhancement in the prediction of the concentration for all gaseous species in the producer gas and tar yield. Furthermore, sensitivity analysis for SEM models has been performed using different higher heating value correlation for woody biomass. (C) 2017 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Aydin2017,
author = {Aydin, E. S. and Yucel, O. and Sadikoglu, H.},
title = {Development of a semi-empirical equilibrium model for downdraft gasification systems},
journal = {Energy},
year = {2017},
volume = {130},
pages = {86--98},
doi = {10.1016/j.energy.2017.04.132}
}
|
| Aydin ES, Yucel O and Sadikoglu H (2017), "Modelling and simulation of a moving interface problem: freeze drying of black tea extract", Heat and Mass Transfer., June, 2017. Vol. 53(6), pp. 2143-2154. |
| Abstract: The moving interface separates the material that is subjected to the freeze drying process as dried and frozen. Therefore, the accurate modeling the moving interface reduces the process time and energy consumption by improving the heat and mass transfer predictions during the process. To describe the dynamic behavior of the drying stages of the freeze-drying, a case study of brewed black tea extract in storage trays including moving interface was modeled that the heat and mass transfer equations were solved using orthogonal collocation method based on Jacobian polynomial approximation. Transport parameters and physical properties describing the freeze drying of black tea extract were evaluated by fitting the experimental data using Levenberg-Marquardt algorithm. Experimental results showed good agreement with the theoretical predictions. |
BibTeX:
@article{Aydin2017a,
author = {Aydin, E. S. and Yucel, O. and Sadikoglu, H.},
title = {Modelling and simulation of a moving interface problem: freeze drying of black tea extract},
journal = {Heat and Mass Transfer},
year = {2017},
volume = {53},
number = {6},
pages = {2143--2154},
doi = {10.1007/s00231-017-1974-y}
}
|
| Ozkan O and Erbil HY (2017), "Interpreting contact angle results under air, water and oil for the same surfaces", Surface Topography-metrology and Properties., June, 2017. Vol. 5(2), pp. 024002. |
| Abstract: Under-water and under-oil superhydropobicity and superhydrophilicity have gained significant attention over the last few years. In this study, contact angles on five flat surfaces (polypropylene, poly(methyl methacrylate), polycarbonate, TEFLON-FEP and glass slide) were measured in water drop-in-air, air bubble-under-water, oil drop-in-air, air bubble-under-oil, oil drop-under-water and water drop-under-oil conditions. Heptane, octane, nonane, decane, dodecane, and hexadecane hydrocarbons were used as oils. Immiscible water/oil pairs were previously mutually saturated to provide thermodynamical equilibrium conditions and their surface and interfacial tensions were determined experimentally. These pairs were used in the two-liquid contact angle measurements. Surface free energies of the solid surfaces in air were determined independently by using the van Oss Good method, using the contact angle results of pure water, ethylene glycol, formamide, methylene iodide and alpha-bromonaphalene. In addition, Zisman's 'critical surface tension' values were also determined for comparison. In theory, the summation of contact angle results in a complementary case would give a total of 180 degrees for ideal surfaces. However, it was determined that there are large deviations from this rule in practical cases and these deviations depend on surface free energies of solids. Three complementary cases of (water-in-air with air bubble-under-water); (oil-in-air with air bubble-under oil); and (oil-under-water with water-under-oil) were investigated in particular to determine the deviations from ideality. A novel approach, named 'complementary hysteresis' [gamma(WA)(cos theta(1) - cos theta(2)) and gamma(OW)(cos theta(6) - cos theta(5)) was developed where gamma(WA) and gamma(OW) represent the interfacial tensions of water/air and oil/water, and theta(1), theta(2), theta(5), and theta(6) were the contact angles of water/air, air bubble/water, oil/water and water/oil respectively. It was experimentally determined that complementary hysteresis varies almost linearly with the surface free energy of the flat solid samples. This is the first report showing the relation of the surface free energy of a solid which is determined under-air with the contact angles obtained on the same solid in different three-phase systems. |
BibTeX:
@article{Ozkan2017,
author = {Ozkan, O. and Erbil, H. Y.},
title = {Interpreting contact angle results under air, water and oil for the same surfaces},
journal = {Surface Topography-metrology and Properties},
year = {2017},
volume = {5},
number = {2},
pages = {024002},
doi = {10.1088/2051-672X/aa6e02}
}
|
| Melikoglu M (2017), "Pumped hydroelectric energy storage: Analysing global development and assessing potential applications in Turkey based on Vision 2023 hydroelectricity wind and solar energy targets", Renewable & Sustainable Energy Reviews., May, 2017. Vol. 72, pp. 146-153. |
| Abstract: According to the Vision 2023 agenda, the Turkish government plans to produce 30% of Turkey's electricity demand from renewable energy sources in 2023. This means hydroelectric, wind and solar energy capacities would increase to 36,000 MW, 20,000 MW and 3000 MW, respectively. Increased hydroelectric capacity would indeed benefit stability and flexibility of the existing energy infrastructure. However, increased wind and solar capacity could bring intermittency problems due to nature of these energy sources. Recently, pumped hydroelectric energy storage (PHES) has become a hot topic in Turkey. And, its potential applications via synergistic utilisation with wind and solar energy to solve the aforementioned intermittency problems is being discussed. Yet, detailed information in the literature about PHES in Turkey is scarce. Therefore, this paper was intended to provide this crucial information. Detailed analysis showed even if all obstacles are overcome and all potential PHES capacity is used PHES could only provide a storage capacity worth equivalent to 0.6-0.8% of Turkey's annual electricity demand in 2023. It is estimated that the overnight capital cost required to develop this PHES potential is between 3.6 and 6.5 billion US$. Even so, there would be serious economic risks of PHES plants. Because, PHES systems are currently net consumers of energy. Current study also showed that instead of focusing on PHES, flexibility of Turkish electricity market could be sustained by diversifying energy sources and increasing nuclear energy capacity. It is estimated that an additional 490 MW of nuclear capacity could provide the same potential PHES capacity. By this way, intermittency problems associated with increased share of solar and wind energy can be easily tackled without imperilling the Vision 2023 energy targets. |
BibTeX:
@article{Melikoglu2017a,
author = {Melikoglu, M.},
title = {Pumped hydroelectric energy storage: Analysing global development and assessing potential applications in Turkey based on Vision 2023 hydroelectricity wind and solar energy targets},
journal = {Renewable & Sustainable Energy Reviews},
year = {2017},
volume = {72},
pages = {146--153},
doi = {10.1016/j.rser.2017.01.060}
}
|
| Melikoglu M (2017), "Modelling and forecasting the demand for jet fuel and bio-based jet fuel in Turkey till 2023", Sustainable Energy Technologies and Assessments., February, 2017. Vol. 19, pp. 17-23. |
| Abstract: Turkey's ambitious Vision 2023 agenda foresees a significant growth in the country's aviation sector. However, forecasts for Turkey's jet fuel demand in the view of Vision 2023 are not available in the published literature. Also, there is no information about the country's potential bio-based jet fuel demand after 2020, when it is plausible to become a mandatory supplement to kerosene. As a result, for the first time in this study, semi-empirical models were generated to provide Turkey's jet fuel and bio-based jet fuel forecasts based on the country's Vision 2023 energy targets. These models were generated taking current market dynamics, business as usual, and the possibility of enhanced economic growth for Turkey based on Vision 2023 energy and economic targets. As a result, Turkey's jet fuel demand in 2023 was estimated at between 4.230 and 7.880 billion litres. Also, it was calculated that Turkey could need up to 0.307 billion litres of bio-based jet fuel in 2023, if its consumption becomes mandatory after 2020. (C) 2016 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Melikoglu2017b,
author = {Melikoglu, M.},
title = {Modelling and forecasting the demand for jet fuel and bio-based jet fuel in Turkey till 2023},
journal = {Sustainable Energy Technologies and Assessments},
year = {2017},
volume = {19},
pages = {17--23},
doi = {10.1016/j.seta.2016.11.005}
}
|
| Kasapgil E, Atici EG, Cicek R, Anac I and Erbil HY (2016), "Superhydrophobic polysiloxane filament growth on non-activated polymer coatings", Rsc Advances. Vol. 6(78), pp. 74921-74928. |
| Abstract: Superhydrophobic polysiloxane nanofilaments were successfully grown on polymer coatings prepared by conventional emulsion polymerization without the application of any activation step for the first time using methyltrichlorosilane as the silane precursor. Both gas phase reactions under a controlled humidity environment and Liquid phase reactions in standard petroleum ether which is open to air were applied during filament growth. Wettability, morphology and transparency of the obtained polysiloxane nanofilaments were characterized by contact angle measurements, scanning electron microscopy and UV-vis transmittance tests respectively. Advancing contact angle values between 166-172 degrees and 157-169 degrees were obtained via the gas phase reactions and the Liquid phase reactions, respectively. It was also shown that polysiloxane nanofilaments can be grown on polystyrene coatings prepared by solution polymerization without any pre-activation step via the Liquid phase filament growth reaction. It was determined that the presence of hydroxyl groups on a polymer coating is not required for the growth of polysiloxane nanofilaments, and only the formation of a water film having an adequate thickness on the polymeric coating surface is sufficient. |
BibTeX:
@article{Kasapgil2016,
author = {Kasapgil, E. and Atici, E. G. and Cicek, R. and Anac, I. and Erbil, H. Y.},
title = {Superhydrophobic polysiloxane filament growth on non-activated polymer coatings},
journal = {Rsc Advances},
year = {2016},
volume = {6},
number = {78},
pages = {74921--74928},
doi = {10.1039/c6ra11958a}
}
|
| Isleroglu H, Kemerlı-Kalbaran T, Özdestan-Ocak Ö, Üren A and Kaymak-Ertekin F (2016), "Steam Assisted Hybrid Cooking Behavior of Semitendinosus Muscle: Heterocyclic Amines Formation, Soluble Protein Degradation, Fat Retention, Surface Color, and Cooking Value", International Journal of Food Properties. Vol. 19(5), pp. 1139-1153. Taylor & Francis. |
| Abstract: Beef (Semitendinosus muscle) was cooked in natural convection, forced convection and steam assisted hybrid oven and saturated steam oven at different oven temperatures until the geometric center of samples reached different end temperatures. Heterocyclic amine (HCA) compounds formation, soluble protein degradation kinetics, cook value, changes in fat content, surface colour and overall acceptance of cooked beef were determined. Soluble protein degradation of beef was considered as first order reaction kinetics and the reaction rate constants, k, were determined in the range of 0.014-0.052 min−1. In steam assisted hybrid oven had higher reaction rate constants compared to that of the convection ovens. The effect of cooking temperature on soluble protein degradation for natural convection, forced convection and steam assisted hybrid oven followed the Arrhenius type of equation with activation energies of 12.45, 14.57 and 60.16 kJ/mol, respectively. Lower HCAs contents, shorter cooking times, lower cook values and lower fat retention were obtained by steam assisted hybrid oven cooking. Steam assisted hybrid cooking could be considered as an alternative cooking method to obtain a healthier product without compromising the eating habits of conventional methods due to better appearance (moderate burned surface) than saturated steam oven samples and a product retaining the most of the nutritional values. |
BibTeX:
@article{Isleroglu2016,
author = {Hilal Isleroglu and Tansel Kemerlı-Kalbaran and Özgül Özdestan-Ocak and Ali Üren and Figen Kaymak-Ertekin},
title = {Steam Assisted Hybrid Cooking Behavior of Semitendinosus Muscle: Heterocyclic Amines Formation, Soluble Protein Degradation, Fat Retention, Surface Color, and Cooking Value},
journal = {International Journal of Food Properties},
publisher = {Taylor & Francis},
year = {2016},
volume = {19},
number = {5},
pages = {1139--1153},
url = {
|
| Cumhur O, Seker M and Sadikoglu H (2016), "Freeze drying of turkey breast meat: Mathematical modeling and estimation of transport parameters", Drying Technology. Vol. 34(5), pp. 584-594. |
| Abstract: Freeze drying is an ideal process to produce high-quality dehydrated food products. In this work, a modified mathematical model was constructed and solved in order to describe quantitatively the dynamic behavior of the primary and secondary drying stages of the freeze drying of turkey breast meat in trays. A numerical method of orthogonal collocation based on polynomial approximation was used to obtain solution of mathematical models. Some transport parameters and physical properties that characterize freeze drying of turkey breast meat were determined by fitting experimental data with the mathematical model using the nonlinear least-square method of the Levenberg-Marquardt algorithm of MATLAB. The best-fitted Knudsen diffusivity constant for water vapor, K-w, film thermal conductivity constant, k(f), effective thermal conductivity of the porous dried layer, k(Ie), desorption rate constant of bound water during the secondary drying stage,k(d), and initial value for weight fraction of bound water in dried layer, found to be 3.1151x10(-5)(T-I+T-x)(0.5)m(2)/s, 2.0580x10(-3)P kW/m(2)K, 44.2x10(-6)[1-0.325exp (-5x10(-3) P)] kW/m K, 5.07x10(-5)s(-1) and 0.3276kg water/kg solid, respectively. By using best-fitted parameters in the dynamic mathematical model, the duration of primary and secondary drying stages for 12.4-mm-thick turkey breast meat slabs were found to be 11.0h and 17h, respectively. The mathematical model was validated with 14.5-mm-thick turkey breast slab. There was good agreement between the experimental data and the theoretical results. |
BibTeX:
@article{Cumhur2016,
author = {Cumhur, O. and Seker, M. and Sadikoglu, H.},
title = {Freeze drying of turkey breast meat: Mathematical modeling and estimation of transport parameters},
journal = {Drying Technology},
year = {2016},
volume = {34},
number = {5},
pages = {584--594},
doi = {10.1080/07373937.2015.1064945}
}
|
| Aras O and Bayramoglu M (2016), "Employing Direct Methanol Fuel Cell Yielded In Situ Methanol Concentrations under Varying Operating Conditions: A Comparative Optimal Search Study", Journal of the Electrochemical Society. Vol. 163(3), pp. F230-F237. |
| Abstract: In the literature there are hundreds of research papers for the synthesis of featured membrane to deal with the methanol crossover. Parallel to these experiments, studies focusing on working methanol concentration are continued to obtain the best results in the existing obstacles. Conducted studies reveal that an optimal concentration exists for each current density depending on operating conditions and operating a system near these points provides benefit to the fuel and energy efficiencies. In this study an approach is presented to minimize the crossover effects and operate the fuel cell at existing optimal concentration values depending on current density and methanol fuel rate. Firstly the performance of Golden Section algorithm (GS) while searching the optimal concentration is explored. Then prediction power of Adaptive Neuro Fuzzy Inference System (ANFIS), training at various operating conditions, is evaluated. Subsequently, ANFIS is evaluated in the control algorithm to determine the optimal concentration and the corresponding voltage. In this way it is aimed to operate the fuel cell yielded in situ concentration control depending on operating conditions. (C) The Author(s) 2015. Published by ECS. All rights reserved. |
BibTeX:
@article{Aras2016,
author = {Aras, O. and Bayramoglu, M.},
title = {Employing Direct Methanol Fuel Cell Yielded In Situ Methanol Concentrations under Varying Operating Conditions: A Comparative Optimal Search Study},
journal = {Journal of the Electrochemical Society},
year = {2016},
volume = {163},
number = {3},
pages = {F230--F237},
doi = {10.1149/2.0941603jes}
}
|
| Yalçın MY and Şeker M (2016), "Effect of salt and moisture content reduction on physical and microbiological properties of salted, pressed and freeze dried turkey meat", LWT - Food Science and Technology. Vol. 68(Supplement C), pp. 153-159. |
| Abstract: Abstract The effect of salt content, pressing and moisture content on textural, micro structural and color characteristics, adsorption isotherms and microbiological count of turkey breast meat were studied. There were no statistically significant differences (P ≥ 0.05) between samples including high salt-moisture and low salt-moisture for color (lightness, redness and yellowness) and textural properties of hardness, cohesiveness, springiness and chewiness parameters and they were determined as 59.10–65.76, 0.30–0.28, 1.27–1.19 and 22.44–22.21, respectively. Total mesophilic aerobic counts, Micrococcus/Staphylococcus counts and yeast/mold counts of samples including low salt and moisture were detected as 3.23, 0, 2.98 (log cfu/g) and they were lower than the same counts of samples including high salt and moisture which were found as 6.66, 6.69, 5.95 (log cfu/g) after 70 days of storage. The reduction of salt content did not increase the growth of these microorganisms if we also decrease the moisture content of turkey meat by freeze drying process. Increase of hardness of turkey meat by drying is not found related to shrinkages according to comparison of air and freeze drying. Reduction of moisture content to 40% reduced freeze dying time to 7 h from 27 h of complete drying in freeze dryer. |
BibTeX:
@article{Yalcin2016,
author = {Meral Yıldırım Yalçın and Mahmut Şeker},
title = {Effect of salt and moisture content reduction on physical and microbiological properties of salted, pressed and freeze dried turkey meat},
journal = {LWT - Food Science and Technology},
year = {2016},
volume = {68},
number = {Supplement C},
pages = {153--159},
url = {http://www.sciencedirect.com/science/article/pii/S0023643815303893},
doi = {10.1016/j.lwt.2015.12.032}
}
|
| Erbil HY (2016), "Improvement of lubricant-infused surfaces for anti-icing applications", Surface Innovations., December, 2016. Vol. 4(4), pp. 214-217. |
| Abstract: Slippery lubricant-infused porous surfaces (SLIPS) were developed recently where a textured solid is impregnated with an immiscible lubricant with a low surface tension to create a smooth liquid overlayer to minimize ice nucleation and ice adhesion. Later, many similar surfaces were produced for the same objective using various liquids (perfluorinated, silicone oil, hydrocarbon and water), which were sometimes termed as 'liquid-impregnated surfaces'. The favourable and adverse properties of SLIPS in anti-icing applications are discussed in this review. The importance of the ice-accretion experiments is also highlighted to evaluate the anti-icing performance. The use of SLIPS containing fluorinated or silicone lubricating layers for anti-icing applications has several drawbacks because of the lubricant loss due to drainage, evaporation and cloaking by contacting water droplets. On the other hand, SLIPS containing water and other aqueous lubricating layers on hygroscopic polymer supports seem to be more promising because of the replenishment of the aqueous lubricant by atmospheric moisture. The use of SLIPS in combination with traditional anti-icing and de-icing techniques or with Joule heating systems to decrease the amount of supplied electrical energy is recommended for future research. |
BibTeX:
@article{Erbil2016,
author = {Erbil, H. Y.},
title = {Improvement of lubricant-infused surfaces for anti-icing applications},
journal = {Surface Innovations},
year = {2016},
volume = {4},
number = {4},
pages = {214--217},
doi = {10.1680/jsuin.16.00026}
}
|
| Gengec NA, Cengiz U and Erbil HY (2016), "Superhydrophobic perfluoropolymer/polystyrene blend films induced by nonsolvent", Applied Surface Science., October, 2016. Vol. 383, pp. 33-41. |
| Abstract: Statistical copolymers of perfluoroalkyl ethyl acrylate (Zonyl-TAN) and methyl methacrylate (MMA) were synthesized in a CO2 polymerization system where a CO2-expanded monomer mixture was formed at 13 MPa, and 80 degrees C by using AIBN as initiator. Flat and superhydrophobic surfaces were subsequently prepared on glass slides by applying a phase separation process where the synthesized p(TAN-co-MMA) copolymer and polystyrene (PS) were dissolved in THE solvent. Ethanol was added as the non-solvent to introduce superhydrophobicity during film formation. Water contact angle on the flat p(TAN-co-MMA) copolymer was 118 degrees and increased up to 170 degrees with the formation of surface roughness. The ratio of the ethanol non-solvent in the blend solution has an important effect on the magnitude of surface roughness during the phase separation process. Both pits and protrusions of 1-10 mu m in size were formed on the surface when non-solvent was used. Surface roughness increased with the increase in the ethanol ratio and the PS content of the blend solution. (C) 2016 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Gengec2016,
author = {Gengec, N. A. and Cengiz, U. and Erbil, H. Y.},
title = {Superhydrophobic perfluoropolymer/polystyrene blend films induced by nonsolvent},
journal = {Applied Surface Science},
year = {2016},
volume = {383},
pages = {33--41},
doi = {10.1016/j.apsusc.2016.04.160}
}
|
| Atici EG, Kasapgil E, Anac I and Erbil HY (2016), "Methyltrichlorosilane polysiloxane filament growth on glass using low Cost solvents and comparison with gas phase reactions", Thin Solid Films., October, 2016. Vol. 616, pp. 101-110. |
| Abstract: Fluorine free, transparent, superhydrophobic polysiloxane filament coatings on glass were successfully prepared using methyltrichlorosilane (MTCS) both via liquid phase reactions using standard hydrocarbons in an open system and gas phase reactions under controlled humidity environment. Wettability, morphology and transparency of the obtained coatings were characterized by contact angle measurements, scanning electron microscopy and UV-vis spectrometer transmittance tests respectively. Superhydrophobic polysiloxane nanofilament coatings were obtained for the first time in an open system using standard petroleum ether having advancing contact angle values (theta(a)) between 156 and 168 degrees. Surfaces having contact angle hysteresis as low as 9 were obtained by varying the reaction time and MTCS concentration in petroleum ether. On the other hand, the relative humidity was found to be the most important factor when compared with the factors such as reaction time and silane concentration to change the morphology and the contact angles of the coatings in the gas phase where 38% RH was found to be the optimum for the growth of polysiloxane nanofilament coatings on glass. Polysiloxane nanofilaments having diameters ranging from 34 up to 42 nm and theta(a) values between 166 and 168 were obtained in the gas phase reactions. The transparency of the surfaces prepared in the gas phase was higher than the ones prepared in the liquid phase. (C) 2016 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Atici2016,
author = {Atici, E. G. and Kasapgil, E. and Anac, I. and Erbil, H. Y.},
title = {Methyltrichlorosilane polysiloxane filament growth on glass using low Cost solvents and comparison with gas phase reactions},
journal = {Thin Solid Films},
year = {2016},
volume = {616},
pages = {101--110},
doi = {10.1016/j.tsf.2016.07.041}
}
|
| Korkut I and Bayramoglu M (2016), "Ultrasound assisted biodiesel production in presence of dolomite catalyst", Fuel., September, 2016. Vol. 180, pp. 624-629. |
| Abstract: Ultrasound (US) assisted transesterification of canola oil in presence of heterogeneous catalysts calcined dolomite and CaO was investigated in comparison to each other. An US generator (200 W, 20 kHz) equipped with an horn type probe (19 mm) was used to study the effect of catalyst amount (3-7 wt.% of oil), methanol/oil molar ratio (4/1-15/1), ultrasound power (30-50 W), temperature (25-60 degrees C) and time (60-120 min) on US assisted biodiesel synthesis. Biodiesel yield reached over 97.4% for calcined dolomite at the end of 90 min and 95.5% for CaO at the end of 75 min. According to the results, US improved the transesterification reaction by reducing necessary time for high biodiesel yield, using calcined dolomite as well CaO as heterogeneous catalyst. (C) 2016 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Korkut2016,
author = {Korkut, I. and Bayramoglu, M.},
title = {Ultrasound assisted biodiesel production in presence of dolomite catalyst},
journal = {Fuel},
year = {2016},
volume = {180},
pages = {624--629},
doi = {10.1016/j.fuel.2016.04.101}
}
|
| Melikoglu M ({2016}), "The role of renewables and nuclear energy in Turkey's Vision 2023 energy targets: Economic and technical scrutiny", RENEWABLE & SUSTAINABLE ENERGY REVIEWS., SEP, {2016}. Vol. {62}, pp. 1-12. |
| Abstract: The Turkish government aims to produce 30% of the country's electricity
demand from renewable energy sources and put two nuclear power plants with nearly 10,000 MW total installed capacity into operation by 2023. In this study, the cost of renewable energy investments based on the Vision 2023 energy targets are calculated in detail, and it is found that Turkey should spend on average 61.0 billion US$ to renewable energy sources to fulfil the Vision 2023 energy targets. Current analysis also clearly showed that Turkey must draw an urgent roadmap to illustrate how it is going to finance these mammoth renewable energy investments. It is also pinpointed that Turkey would spend nearly 50.0 billion US$ to its two new nuclear power plants in the next decade. Thus totalling the renewable and nuclear energy investments to nearly 110 billion US$ or approximately 90% of Turkey's estimated energy spending by 2023. Also, detailed analysis of the literature showed that only 2400 MW of the anticipated nuclear capacity can be put into operation by 2023. Consequently, a slight delay in the Vision 2023 energy targets can be expected if no urgent action is taken by the Turkish government. (C) 2016 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Melikoglu2016,
author = {Melikoglu, Mehmet},
title = {The role of renewables and nuclear energy in Turkey's Vision 2023 energy targets: Economic and technical scrutiny},
journal = {RENEWABLE & SUSTAINABLE ENERGY REVIEWS},
year = {2016},
volume = {62},
pages = {1--12},
doi = {{10.1016/j.rser.2016.04.029}}
}
|
| Ozbay S and Erbil HY (2016), "Ice accretion by spraying supercooled droplets is not dependent on wettability and surface free energy of substrates", Colloids and Surfaces A-physicochemical and Engineering Aspects., September, 2016. Vol. 504, pp. 210-218. |
| Abstract: Three different characterization tests namely, ice adhesion strength, drop freezing time and a newly developed ice accretion method were applied to surfaces which were commonly used in anti-icing research such as aluminum, stainless steel, copper, styrene butadiene rubber, polypropylene and polytetrafluoroethylene in order to investigate the effect of their water wettability and surface free energies on their anti-icing performances. It was found that ice adhesion strengths increased and drop freezing times decreased with the increase of the total surface free energies and decrease of the water contact angles on these surfaces similar to previously published reports however, no direct relationship was found between the ice accretion results and solid wettability, surface free energies and the reasons were discussed in terms of heterogeneous nucleation mechanisms. (C) 2016 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Ozbay2016,
author = {Ozbay, S. and Erbil, H. Y.},
title = {Ice accretion by spraying supercooled droplets is not dependent on wettability and surface free energy of substrates},
journal = {Colloids and Surfaces A-physicochemical and Engineering Aspects},
year = {2016},
volume = {504},
pages = {210--218},
doi = {10.1016/j.colsurfa.2016.05.065}
}
|
| Yucel O and Hastaoglu MA (2016), "Comprehensive Study of Steam Reforming of Methane in Membrane Reactors", Journal of Energy Resources Technology-transactions of the Asme., September, 2016. Vol. 138(5), pp. 052204. |
| Abstract: A 2D model and heat transfer mechanism are proposed to analyze and study oxidative steam reforming of methane (OSRM) in a membrane reactor. The model describes mass and thermal dispersions for gas and solid phases. It also accounts for transport through the membrane. The effects of operating parameters on methane conversion and H-2 yield are analyzed. The parameters considered are the bed temperature (800-1100 K), molar oxygen-to-carbon ratio (0.0-0.5), and steam-to-carbon ratio (1-4). The results show that our model prevents overestimation and provides valuable additional information about temperature and concentration gradients in membrane reactor which is not available in a simple one-dimensional approach. Simulation results show that large temperature and concentration gradients cannot be avoided. The particle properties and the bed diameter have a considerable effect on the extent of gas mixing. Effective gas mixing coefficient also increases with increasing gas and solid velocity. In membrane reactor, simulation results show that mixing which depends on operational and design parameters has a strong effect on the hydrogen conversion. Also, the removal of hydrogen with membranes breaks equilibrium barrier leading to efficient production of hydrogen, reduced reactor size, and tube lengths. The model can be used in real-time simulation of industrial reactors for control and optimization purposes. |
BibTeX:
@article{Yucel2016,
author = {Yucel, O. and Hastaoglu, M. A.},
title = {Comprehensive Study of Steam Reforming of Methane in Membrane Reactors},
journal = {Journal of Energy Resources Technology-transactions of the Asme},
year = {2016},
volume = {138},
number = {5},
pages = {052204},
doi = {10.1115/1.4032733}
}
|
| Dursun B, Sar T, Ata A, Morcrette M, Akbas MY and Demir-Cakan R (2016), "Pyrolyzed bacterial cellulose-supported SnO2 nanocomposites as high-capacity anode materials for sodium-ion batteries", Cellulose., August, 2016. Vol. 23(4), pp. 2597-2607. |
| Abstract: Room-temperature sodium-based batteries have the potential for meeting large-scale grid energy storage needs. Inspired by the advancement of the design and building of electrode materials in lithium ion batteries, improved nano-architectured electrodes can be created for sodium-ion batteries, allowing increased electron transport kinetics and conductivities. Here, nanocomposites with 3D porous structures are reported as a high-capacity anode material for sodium-ion batteries by using an easy, low-cost and environmentally friendly synthesis of pyrolyzed bacterial celluloses (PBCs). Bacterial celluloses (BCs) produced by the Gluconacetobacter xylinus strain are pyrolyzed at 500, 750 and 1000 A degrees C, resulting 50, 130 and 110 mAh g(-1) capacities over 80 numbers of cycles, respectively, in the presence of the binary ethylene carbonate-propylene carbonate mixture. In order to increase the cell performances, in situ coated SnO2 nanoparticles with bacterial cellulose (SnO2@PBC) are produced by addition as synthesized 5-nm-sized SnO2 nanoparticles into the BC growth medium together with the G. xylinus strain. Following the pyrolysis at 500 A degrees C, the SnO2@PBC composite is better able to handle the accommodation of the dramatic volume change of the incorporated SnO2 nanoparticles because of the interaction of oxygen-containing moieties of bacterial cellulose nanofibrils with the SnO2 nanoparticles during cellulose production. The resulting SnO2@PBC composite presents highly stable capacity retention of around 400 mAh g(-1) capacities at C/10 current density over 50 numbers of cycles. |
BibTeX:
@article{Dursun2016,
author = {Dursun, B. and Sar, T. and Ata, A. and Morcrette, M. and Akbas, M. Y. and Demir-Cakan, R.},
title = {Pyrolyzed bacterial cellulose-supported SnO2 nanocomposites as high-capacity anode materials for sodium-ion batteries},
journal = {Cellulose},
year = {2016},
volume = {23},
number = {4},
pages = {2597--2607},
doi = {10.1007/s10570-016-0966-2}
}
|
| Arslan M, Kiskan B, Cengiz EC, Demir-Cakan R and Yagci Y (2016), "Inverse vulcanization of bismaleimide and divinylbenzene by elemental sulfur for lithium sulfur batteries", European Polymer Journal., July, 2016. Vol. 80, pp. 70-77. |
| Abstract: A novel approach to fabricate sulfur rich thermosets as materials for Li-S batteries is described. For this purpose, polybismaleimide copolymers were synthesized by reacting bismaleimide (BMI) monomer and elemental sulfur at 180 degrees C. Parameters such as monomers and feed ratios on the polymerization were studied. Divinylbenzenes were also used in the formulation to increase sulfur feed ratios up to 70 wt%. The thermal stability of the copolymers was also investigated by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). BMI based copolymers had shown excellent thermal stability and yielded up to 40% char yield at 800 degrees C. The obtained insoluble copolymers were used in Li-S battery applications. Thus, galvanostatic discharge-charge experiments were carried out to evaluate the electrochemical performance of these materials. Both 30% sulfur containing, poly(S-BMI)30%, and 70% sulfur containing, Poly(S-BMI-DVB)70%, composites exhibited a staircase voltage profile which is typical for Li-S batteries. These materials, as Li-S battery cathodes, demonstrated around 400 mA h/g specific capacities at 50 cycles. (C) 2016 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Arslan2016,
author = {Arslan, M. and Kiskan, B. and Cengiz, E. C. and Demir-Cakan, R. and Yagci, Y.},
title = {Inverse vulcanization of bismaleimide and divinylbenzene by elemental sulfur for lithium sulfur batteries},
journal = {European Polymer Journal},
year = {2016},
volume = {80},
pages = {70--77},
doi = {10.1016/j.eurpolymj.2016.05.007}
}
|
| Tarlak F, Ozdemir M and Melikoglu M (2016), "Computer vision system approach in colour measurements of foods: Part II. validation of methodology with real foods", Food Science and Technology., July, 2016. Vol. 36(3), pp. 499-504. |
| Abstract: The colour of food is one of the most important factors affecting consumers' purchasing decision. Although there are many colour spaces, the most widely used colour space in the food industry is L*a*b* colour space. Conventionally, the colour of foods is analysed with a colorimeter that measures small and non-representative areas of the food and the measurements usually vary depending on the point where the measurement is taken. This leads to the development of alternative colour analysis techniques. In this work, a simple and alternative method to measure the colour of foods known as "computer vision system" is presented and justified. With the aid of the computer vision system, foods that are homogenous and uniform in colour and shape could be classified with regard to their colours in a fast, inexpensive and simple way. This system could also be used to distinguish the defectives from the non-defectives. Quality parameters of meat and dairy products could be monitored without any physical contact, which causes contamination during sampling. |
BibTeX:
@article{Tarlak2016,
author = {Tarlak, F. and Ozdemir, M. and Melikoglu, M.},
title = {Computer vision system approach in colour measurements of foods: Part II. validation of methodology with real foods},
journal = {Food Science and Technology},
year = {2016},
volume = {36},
number = {3},
pages = {499--504},
doi = {10.1590/1678-457X.02616}
}
|
| Kayhan O, Yucel O and Hastaoglu MA (2016), "Simulation and control of serviceable stratospheric balloons traversing a region via transport phenomena and PID", Aerospace Science and Technology., June, 2016. Vol. 53, pp. 232-240. |
| Abstract: Balloon systems can be used as alternatives to communication satellites for a number of applications. Launching, flight and safe landing of zero pressure high altitude stratospheric balloons were simulated in 3-D using transport phenomena, process control techniques and a flight gas Compress-Release-system. A model developed was numerically solved and the results were validated using NASA test flight data. The effect of PID control on Compress-Release mechanism is discussed in detail. It was found that with this model it is possible to place the balloons at target altitudes, extend flight time, ensure their horizontal flights over desired coordinates and interfere with the balloon system whenever needed for technical service without using ballast under varying environmental conditions. The simulation was applied to a set of balloons following several routes in Turkey using actual wind data. The results would be helpful for the design, operation and control of safe, reliable and serviceable high altitude stratospheric balloons. (c) 2016 Elsevier Masson SAS. All rights reserved. |
BibTeX:
@article{Kayhan2016,
author = {Kayhan, O. and Yucel, O. and Hastaoglu, M. A.},
title = {Simulation and control of serviceable stratospheric balloons traversing a region via transport phenomena and PID},
journal = {Aerospace Science and Technology},
year = {2016},
volume = {53},
pages = {232--240},
doi = {10.1016/j.ast.2016.03.013}
}
|
| Erkan HS, Engin GO, Ince M and Bayramoglu MR (2016), "Effect of carbon to nitrogen ratio of feed wastewater and sludge retention time on activated sludge in a submerged membrane bioreactor", Environmental Science and Pollution Research., June, 2016. Vol. 23(11), pp. 10742-10752. |
| Abstract: This paper investigated the effects of extracellular polymeric substances (EPS) on the activated sludge rheology in a submerged membrane bioreactor (sMBR) operated at different sludge retention time (SRT) values and different carbon to nitrogen ratios (C/N) of feed wastewater. The C/N ratios of the feed were adjusted accordingly so that synthetic wastewaters prepared simulated municipal wastewater, non-toxic wastewater with high C/N ratio and non-toxic wastewater with low C/N ratio. A number of important operational parameters such as mixed liquor suspended solid (MLSS), protein fraction of EPS (EPSp), carbohydrate fraction of EPS (EPSc), protein fraction of soluble microbial product (SMPp), carbohydrate fraction of SMP (SMPc), apparent viscosity, critical flux and hydrophobicity in mixed liquor and their correlations were investigated in the sMBR systems operated. The statistical analysis indicated that the C/N ratio of feed, SRT, MLSS and SMPc were found to have positive effects on apparent viscosity at three different shear rates. On the other hand, a negative impact was detected between the apparent viscosities and the critical fluxes. It was also observed that there is a significant positive correlation between hydrophobicity and both EPSp and SMPp. |
BibTeX:
@article{Erkan2016,
author = {Erkan, H. S. and Engin, G. O. and Ince, M. and Bayramoglu, M. R.},
title = {Effect of carbon to nitrogen ratio of feed wastewater and sludge retention time on activated sludge in a submerged membrane bioreactor},
journal = {Environmental Science and Pollution Research},
year = {2016},
volume = {23},
number = {11},
pages = {10742--10752},
doi = {10.1007/s11356-016-6215-2}
}
|
| Depardieu M, Demir-Cakan R, Sanchez C, Birot M, Deleuze H, Morcrette M and Backov R (2016), "On the effect of gold nanoparticles loading within carbonaceous macro-mesocellular foams toward lithium-sulfur battery performances", Solid State Sciences., May, 2016. Vol. 55, pp. 112-120. |
| Abstract: Novel carbonaceous monolith foams loaded with gold nanoparticles have been synthesized and thoroughly characterized over several length scale. Their Li-S battery electrode capabilities have been assessed and compared while varying the gold loading and subsequently the specific surface area. Their capacities expressed in either mass (mA h g(-1)) or volume (mA h cm(-3)) dimensions have shown that specific surface area and nanoparticles loading are acting in a strong partitioning mode, rather than a cooperative mode, which does not favor the use of gold nanoparticles loading as efficient incremental path toward optimizing porous carbonaceous-based Li-S battery electrodes. (C) 2016 Elsevier Masson SAS. All rights reserved. |
BibTeX:
@article{Depardieu2016,
author = {Depardieu, M. and Demir-Cakan, R. and Sanchez, C. and Birot, M. and Deleuze, H. and Morcrette, M. and Backov, R.},
title = {On the effect of gold nanoparticles loading within carbonaceous macro-mesocellular foams toward lithium-sulfur battery performances},
journal = {Solid State Sciences},
year = {2016},
volume = {55},
pages = {112--120},
doi = {10.1016/j.solidstatesciences.2016.02.015}
}
|
| Yucel O and Hastaoglu MA (2016), "Kinetic modeling and simulation of throated downdraft gasifier", Fuel Processing Technology., April, 2016. Vol. 144, pp. 145-154. |
| Abstract: An imbert 'throated' gasifier which has hourglass heart and varying axial area and nozzles for injection of gasification agents has been studied. The transport of reacting gas-solid two-phase mixture through the gasifier has been mathematically modeled transiently. Downdraft gasification in such a complex system has so many variables and is quite cumbersome to describe. For the first time throated gasifiers are modeled as realistically as possible. The resulting set of transport, structural, kinetic and auxiliary equations was solved via numerical methods. The modeling work was experimentally validated using a 10 kW gasifier. The actual geometry of the experimental setup was used in the model. The model results were in line with the experimental results. Throated combustion zone causes better distribution of heat and reduces heat loss. With the same core size and solid consumption, stratified gasifier output was 24.5% less than throated one. The model exit had 25.85% CO; 18.25% H-2; 7.84% CO2; 2.9% CH4; while the experiment had 35.07-20.77% CO; 18.30-13.66% H-2; 13.68-5.95% CO2; 6.7-1.2% CH4; the rest was N-2. The model can be applied to different geometries. (C) 2015 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Yucel2016a,
author = {Yucel, O. and Hastaoglu, M. A.},
title = {Kinetic modeling and simulation of throated downdraft gasifier},
journal = {Fuel Processing Technology},
year = {2016},
volume = {144},
pages = {145--154},
doi = {10.1016/j.fuproc.2015.12.023}
}
|
| Tarlak F, Ozdemir M and Melikoglu M (2016), "Computer vision system approach in colour measurements of foods: Part I. development of methodology", Food Science and Technology., April, 2016. Vol. 36(2), pp. 382-388. |
| Abstract: The colour assessment ability of the computer vision system is investigated and the data are compared with colour measurements taken by a conventional colorimeter. Linear and quadratic models are built to improve currently used methodology for the conversion of RGB colour units to L* a* b* colour space. For this purpose, two innovative ideas are proposed and tested. First, substantial amount of colour tones is generated to cover as many points in the colour space as possible. Secondly, the colour space is calibrated separately, whereas in previous research in the literature, the colour space is calibrated simultaneously. It is found that the RGB colour units to L* a* b* colour space transformation approach proposed in this study is more logical and more accurate, and the prediction performance of the quadratic model is superior over the linear model. |
BibTeX:
@article{Tarlak2016a,
author = {Tarlak, F. and Ozdemir, M. and Melikoglu, M.},
title = {Computer vision system approach in colour measurements of foods: Part I. development of methodology},
journal = {Food Science and Technology},
year = {2016},
volume = {36},
number = {2},
pages = {382--388},
doi = {10.1590/1678-457X.11615}
}
|
| Calik MK and Ozdemir M (2016), "Synthesis, characterization and, swelling behavior of semi-IPN nanocomposite hydrogels of alginate with poly(N-isopropylacrylamide) crosslinked by nanoclay", Journal of Applied Polymer Science., March, 2016. Vol. 133(12), pp. 43222. |
| Abstract: pH and temperature responsive nanocomposite hydrogels were synthesized with sodium alginate (NaAlg), N-isopropylacrylamide (NIPA), and nanoclay. The structure, morphology, thermal behavior, and swelling and deswelling behaviors of the hydrogels were studied. The NaAlgm/PNIPA/Clayn hydrogels revealed a highly porous structure in which the pore sizes decreased and the amount of pores increased with increasing the nanoclay content in the hydrogels. PNIPA retained its own characteristics regardless of the amount of NaAlg and nanoclay. The effect of pH and nanoclay content on the swelling and effect of temperature on the deswelling behavior were investigated. The equilibrium swelling ratios of the nanocomposite hydrogels increased with increasing the pH from 2 to 6. The maximum swelling was attained at pH 6. Deswelling increased with increasing the nanoclay content in the hydrogels. The hydrogels were found to be pH and temperature responsive. (C) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43222. |
BibTeX:
@article{Calik2016,
author = {Calik, M. K. and Ozdemir, M.},
title = {Synthesis, characterization and, swelling behavior of semi-IPN nanocomposite hydrogels of alginate with poly(N-isopropylacrylamide) crosslinked by nanoclay},
journal = {Journal of Applied Polymer Science},
year = {2016},
volume = {133},
number = {12},
pages = {43222},
doi = {10.1002/app.43222}
}
|
| Demir-Cakan R, Morcrette M and Tarascon JM (2015), "Use of ion-selective polymer membranes for an aqueous electrolyte rechargeable Li-ion-polysulphide battery", Journal of Materials Chemistry A. Vol. 3(6), pp. 2869-2875. |
| Abstract: Aqueous electrolyte Li-ion-polysulphide batteries offer great promise due to the use of low-cost and abundant raw materials. Following up on our previous studies in which we explored a totally new practical battery chemistry coupling a well-known cathode material in Li-ion batteries (i.e. LiMn2O4) with a dissolved polysulphide anode, herein we aim to further develop the system by replacing the ceramic membrane with an ion-selective polymer membrane, allowing cost-effective and higher energy density options. After tuning the osmotic movements inside the membrane, dissolved polysulphide leakage from one compartment to another is successfully eliminated. With the additional use of porous silica serving as an absorbent for sulphur-based gaseous products, a 1.5 V average voltage together with a stable cycling profile over 200 cycles at high current density regimes are easily achieved. |
BibTeX:
@article{Demir-Cakan2015a,
author = {Demir-Cakan, R. and Morcrette, M. and Tarascon, J. M.},
title = {Use of ion-selective polymer membranes for an aqueous electrolyte rechargeable Li-ion-polysulphide battery},
journal = {Journal of Materials Chemistry A},
year = {2015},
volume = {3},
number = {6},
pages = {2869--2875},
doi = {10.1039/c4ta05756b}
}
|
| Ozbay S, Yuceel C and Erbil HY (2015), "Improved Icephobic Properties on Surfaces with a Hydrophilic Lubricating Liquid", Acs Applied Materials & Interfaces., October, 2015. Vol. 7(39), pp. 22067-22077. |
| Abstract: Slippery liquid-infused porous surfaces were developed recently for icephobic surface applications. Perfluorinated liquids, silicone oil, hydrocarbon, and water were used as lubricating liquids to form a continuous layer on a suitable substrate to prevent icing. However, ice accretion performances of these surfaces have not been reported previously depending on the type of the lubricant. In this work, fluorinated aliphatics, polyalphaolefin, silicone oil, and decamethylcyclopenta siloxane were used as hydrophobic lubricants; water, ethylene glycol, formamide, and water glycerine mixture were used as hydrophilic lubricants to be impregnated by hydrophobic polypropylene and hydrophilic cellulose-based filter paper surfaces; ice accretion, drop freezing delay time, and ice adhesion strength properties of these surfaces were examined; and the results were compared to those of the reference surfaces such as aluminum, copper, polypropylene, and polytetrafluoroethylene. An ice accretion test method was also developed to investigate the increase of the mass of formed ice gravimetrically by spraying supercooled water onto these surfaces at different subzero temperatures ranging between -1 and -5 degrees C. It was determined that hydrophilic solvents (especially a water glycerine mixture) that impregnated hydrophilic porous surfaces would be a promising candidate for anti-icing applications at -2 degrees C and 56-83% relative humidity because ice accretion and ice adhesion strength properties of these surface decreased simultaneously in these conditions. |
BibTeX:
@article{Ozbay2015,
author = {Ozbay, S. and Yuceel, C. and Erbil, H. Y.},
title = {Improved Icephobic Properties on Surfaces with a Hydrophilic Lubricating Liquid},
journal = {Acs Applied Materials & Interfaces},
year = {2015},
volume = {7},
number = {39},
pages = {22067--22077},
doi = {10.1021/acsami.5b07265}
}
|
| Aras O and Bayramoglu M (2015), "Control Applications (ANFIS/Fuzzy/PID) over Mathematical Model of DMFC System: Experimental and Simulation Studies", International Journal of Electrochemical Science., October, 2015. Vol. 10(10), pp. 8103-8123. |
| Abstract: Environmental pollution, depletion of fossil fuel reserves and energy needs of a growing world population, are among the important issues concerning the future of energy. In this context, fuel cells are considered as alternative energy sources. In this study, one cell direct methanol fuel cell system, consisting of various sensors and control elements and controlling system are built. Experimental temperature control is conducted with fuzzy control technique over the systems. Then, useful and simple mathematical model that can adequately represent the system is established and the parameters of this model are determined by particle swarm optimization (PSO) method using experimental data. In addition, ANFIS model of the system with the 4-input and 1 output is established through the polarization curves. Also, membership function types and numbers of input variables having an impact on the ANFIS modeling are investigated. Beside to the experimental PID concentration control with sensor, ANFIS is tested for the sensor-less concentration control over the mathematical model in the simulation studies. |
BibTeX:
@article{Aras2015,
author = {Aras, O. and Bayramoglu, M.},
title = {Control Applications (ANFIS/Fuzzy/PID) over Mathematical Model of DMFC System: Experimental and Simulation Studies},
journal = {International Journal of Electrochemical Science},
year = {2015},
volume = {10},
number = {10},
pages = {8103--8123}
}
|
| Ozbay S and Erbil HY (2015), "Superhydrophobic and oleophobic surfaces obtained by graft copolymerization of perfluoroalkyl ethyl acrylate onto SBR rubber", Colloids and Surfaces A-physicochemical and Engineering Aspects., September, 2015. Vol. 481, pp. 537-546. |
| Abstract: Superhydrophobic and oleophobic rubbery coatings were prepared by spraying perfluoroalkyl ethyl acrylate (Zonyl TA-N) grafted styrene butadiene rubber (SBR) solution in toluene after addition of hydrophilic and hydrophobic fumed silica powders onto glass. Grafting onto SBR has been performed by free radical copolymerization in toluene using different Zonyl TA-N feed compositions. Molecular weights of the graft copolymers were determined by GPC and intrinsic viscosity measurements. Thin films of Zonyl TA-N grafted SBR copolymers were prepared by dip coating glass slides into toluene solutions of SBR-g-Zonyl TA-N with varying fluoromonomer contents and their surface free energies were determined by contact angle measurements. The increase in Zonyl TA-N content resulted in a considerable decrease of the total surface free energy of the grafted SBR film. Later, superhydrophobic and oleophobic surfaces were prepared by adding hydrophilic and hydrophobic fumed silica powders into graft copolymer solutions and spraying onto glass. The effect of the Zonyl TA-N content in the graft copolymer, type of silica and its weight concentration in the solution on the water and hexadecane contact angle values, on the surface morphology and mechanical durability of the coatings were investigated. The highest water contact angle of the SBR-g-Zonyl TA-N/SiO2 hybrid coatings was determined to be 162 degrees and hexadecane contact angle 147 degrees after adjusting the silica type, solids content and fluoroacrylate/SBR composition of the graft copolymer spray solution. (C) 2015 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Ozbay2015a,
author = {Ozbay, S. and Erbil, H. Y.},
title = {Superhydrophobic and oleophobic surfaces obtained by graft copolymerization of perfluoroalkyl ethyl acrylate onto SBR rubber},
journal = {Colloids and Surfaces A-physicochemical and Engineering Aspects},
year = {2015},
volume = {481},
pages = {537--546},
doi = {10.1016/j.colsurfa.2015.05.049}
}
|
| Han W, Lam WC, Melikoglu M, Wong MT, Leung HT, Ng CL, Yan P, Yeung SY and Lin CSK (2015), "Kinetic Analysis of a Crude Enzyme Extract Produced via Solid State Fermentation of Bakery Waste", Acs Sustainable Chemistry & Engineering., September, 2015. Vol. 3(9), pp. 2043-2048. |
| Abstract: In this study, glucoamylase extract was produced from various bakery wastes under solid state fermentation by Aspergillus awamori and Aspergillus oryzae. The highest glucoamylase activities obtained from bread and cake waste with A. awamori were 240.7 U/g of bread (db) and 134.9 U/g of cake (db), respectively, and 83.3 U/g of pastry (db) using A. oryzae. Kinetic studies showed that glucoamylase obtained from bakery wastes should have at least two conformations under the two temperature ranges of 30-55 degrees C and 60-70 degrees C. Thermodynamics stated that the range 30-55 degrees C was considered to be the optimal temperature for glucoamylase activity and subsequent food waste hydrolysis. The crude enzyme extracts were then used in the hydrolysis of restaurant food waste to produce a glucose-rich hydrolysate. It was found that using combined crude glucoamylase (produced from A. awamori and A. oryzae) could achieve higher glucose production (0.515 g of glucose/g of food waste) than using glucoamylase alone (produced from A. awamori). Results obtained from this study demonstrate that the proposed bioprocess could be successfully applied for the bioconversion of food waste into value-added products in a sustainable way. |
BibTeX:
@article{Han2015,
author = {Han, W. and Lam, W. C. and Melikoglu, M. and Wong, M. T. and Leung, H. T. and Ng, C. L. and Yan, P. and Yeung, S. Y. and Lin, C. S. K.},
title = {Kinetic Analysis of a Crude Enzyme Extract Produced via Solid State Fermentation of Bakery Waste},
journal = {Acs Sustainable Chemistry & Engineering},
year = {2015},
volume = {3},
number = {9},
pages = {2043--2048},
doi = {10.1021/acsuschemeng.5b00323}
}
|
| Aynali F and Ciftcioglu GAA (2015), "Thermodynamic Study: C-H Bond Activation of Methane with OsO+", Acta Physica Polonica A., August, 2015. Vol. 128(2B), pp. B167-B169. |
| Abstract: Catalysis plays a critical role in the accomplishment of industrially significant chemical transformations, by requiring less energy investment in underlying processes. Computational chemistry has had a pronounced impact on the understanding of the role of catalysts at the atomic and molecular level, contributing to design of more efficient catalysts. In this study, we compute thermochemical properties attending C-H bond activation of methane by OsO+ and enabling subsequent dehydrogenation and dehydration reactions. It is found that the dehydrogenation channel is thermodynamically more favorable. This study should contribute to the understanding of C-H bond activation using homogeneous catalysis of partial oxidation of natural gas (methane) leading to formation of the easily transported liquid fuel methanol. |
BibTeX:
@article{Aynali2015,
author = {Aynali, F. and Ciftcioglu, G. A. A.},
title = {Thermodynamic Study: C-H Bond Activation of Methane with OsO+},
journal = {Acta Physica Polonica A},
year = {2015},
volume = {128},
number = {2B},
pages = {B167--B169},
doi = {10.12693/APhysPolA.128.B-167}
}
|
| Ergan BT, Bayramoglu M and Ozcan S (2015), "Emulsion polymerization of styrene under continuous microwave irradiation", European Polymer Journal., August, 2015. Vol. 69, pp. 374-384. |
| Abstract: MW-assisted emulsion polymerization of styrene (M) is examined in this study. Six process variables namely, H2O/M, SDS/M, KPS/M, temperature (T), reaction time (t) and MW power density (P) were investigated in comparison with the conventional heating (CH) method to assess their effects on the polymerization yield and the specific MW energy consumption. An experimental system was designed to keep both T and P continuous and constant during the polymerization. Based on a systematic study, it is found that MW power accelerates the polymerization rate, especially in the initiation step of the polymerization. While 95% conversion was achieved in 40 min under P = 0.8 kW dm(-3), 90 min was necessary for CH method to reach the same conversion level. Polymers obtained by MW and CH methods under the same process conditions were found to have the same structural and thermal characteristics. (C) 2015 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Ergan2015,
author = {Ergan, B. T. and Bayramoglu, M. and Ozcan, S.},
title = {Emulsion polymerization of styrene under continuous microwave irradiation},
journal = {European Polymer Journal},
year = {2015},
volume = {69},
pages = {374--384},
doi = {10.1016/j.eurpolymj.2015.06.021}
}
|
| Erbil HY (2015), "Control of stain geometry by drop evaporation of surfactant containing dispersions", Advances in Colloid and Interface Science., August, 2015. Vol. 222, pp. 275-290. |
| Abstract: Control of stain geometry by drop evaporation of surfactant containing dispersions is an important topic of interest because it plays a crucial role in many applications such as forming templates on solid surfaces, in ink-jet printing, spraying of pesticides, micro/nano material fabrication, thin film coatings, biochemical assays, deposition of DNA/RNA micro-arrays, and manufacture of novel optical and electronic materials. This paper presents a review of the published articles on the diffusive drop evaporation of pure liquids (water), the surfactant stains obtained from evaporating drops that do not contain dispersed particles and deposits obtained from drops containing polymer colloids and carbon based particles such as carbon nanotubes, graphite and fullerenes. Experimental results of specific systems and modeling attempts are discussed. This review also has some special subtopics such as suppression of coffee-rings by surfactant addition and "stick-slip" behavior of evaporating nanosuspension drops. In general, the drop evaporation process of a surfactant/particle/substrate system is very complex since dissolved surfactants adsorb on both the insoluble organic/inorganic micro/nanoparticles in the drop, on the air/solution interface and on the substrate surface in different extends. Meanwhile, surfactant adsorbed particles interact with the substrate giving a specific contact angle, and free surfactants create a solutal Marangoni flow in the drop which controls the location of the particle deposition together with the rate of evaporation. In some cases, the presence of a surfactant monolayer at the air/solution interface alters the rate of evaporation. At present, the magnitude of each effect cannot be predicted adequately in advance and consequently they should be carefully studied for any system in order to control the shape and size of the final deposit. (C) 2014 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Erbil2015,
author = {Erbil, H. Y.},
title = {Control of stain geometry by drop evaporation of surfactant containing dispersions},
journal = {Advances in Colloid and Interface Science},
year = {2015},
volume = {222},
pages = {275--290},
doi = {10.1016/j.cis.2014.08.004}
}
|
| Melikoglu M, Lin CSK and Webb C (2015), "Solid state fermentation of waste bread pieces by Aspergillus awamori: Analysing the effects of airflow rate on enzyme production in packed bed bioreactors", Food and Bioproducts Processing., July, 2015. Vol. 95, pp. 63-75. |
| Abstract: The aim of this study was to optimise airflow rate for glucoamylase and protease production from waste bread via solid state fermentation by Aspergillus awamori in packed bed bioreactors. Airflow rates, between 0.40 and 3.00 vvm, were tested. In all experiments, the fungal growth was almost uniform throughout the solids. Fungi grew both on and within the substrate and fungal cakes were formed. The highest glucoamylase and protease activities were recorded as 130.8 U/g bread (db) and 80.3 U/g bread (db) in the experiments with 1.50 vvm airflow rate, respectively. These values are 27.2% and 32.3% higher than the glucoamylase and protease activities obtained in petri dish experiments with static air. At 1.50 vvm airflow rate, the dry weight of the solids had decreased to 46% of the initial value at the end of the fermentation. The temperature of the solids increased up to 37.5 degrees C with high axial temperature gradients due to high metabolic activity. The average moisture content of the solids first decreased to 150% (db) and then increased to 275% (db) by the end of the fermentation. Both above and below 1.50 vvm airflow rate, enzyme production and fungal growth were affected significantly. Also, a Gaussian-based mathematical model was developed to model the effects of airflow rate on enzyme production. The model fitted almost seamlessly to the experimental data. Thus, this study clearly showed the effects of aeration on glucoamylase and protease production from waste bread under solid state fermentations. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. |
BibTeX:
@article{Melikoglu2015,
author = {Melikoglu, M. and Lin, C. S. K. and Webb, C.},
title = {Solid state fermentation of waste bread pieces by Aspergillus awamori: Analysing the effects of airflow rate on enzyme production in packed bed bioreactors},
journal = {Food and Bioproducts Processing},
year = {2015},
volume = {95},
pages = {63--75},
doi = {10.1016/j.fbp.2015.03.011}
}
|
| Demir-Cakan R (2015), "Targeting the role of lithium sulphide formation for the rapid capacity fading in lithium-sulphur batteries", Journal of Power Sources., May, 2015. Vol. 282, pp. 437-443. |
| Abstract: This work aims to study the reasons for the rapid capacity fading in the field of lithium-sulphur batteries. It is found that the formation of non-soluble and insulating lithium sulphide, Li2S, upon sulphur reduction is one of the main reasons to account for the capacity fade due to its relatively low electrochemical activity and blocking of the carbon framework. A variety of analytical techniques are used to assess the formation of Li2S and visualize the resulting morphological changes in a mesoporous carbon/sulphur composite (MCS) during battery operation. It is shown that simply changing the cut-off voltages can alter retention and resistance of the cells during cycling. Since the electrochemical activity of lithium polysulphides decreases with the order, elimination of low order of polysulphides is considered critical. Thus, in order to oxidize the least sulphur reduction specie, Li2S, two different additives are suggested; namely an electrolyte additive, Lil, or an electrode additive, V2O5. Incorporation of the one of these components into the MCS composite enables the delivery of higher capacities (i.e. as compared to a bare C/S composite). The increased capacity is linked not only to the co-cathode materials, which contribute to the total capacity, but also to the oxidizing agent and internal redox mediator role of the additives. (C) 2015 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Demir-Cakan2015,
author = {Demir-Cakan, R.},
title = {Targeting the role of lithium sulphide formation for the rapid capacity fading in lithium-sulphur batteries},
journal = {Journal of Power Sources},
year = {2015},
volume = {282},
pages = {437--443},
doi = {10.1016/j.jpowsour.2015.02.066}
}
|
| Acar B, Sadikoglu H and Doymaz I (2015), "Freeze-drying Kinetics and Diffusion Modeling of Saffron (crocus Sativus L.)", Journal of Food Processing and Preservation., April, 2015. Vol. 39(2), pp. 142-149. |
| Abstract: The freeze drying is a suitable dehydration process for saffron that contains heat-sensitive volatile and aroma-yielding compounds such as crocin (act as a coloring agent), picrocrocin (responsible for the taste) and safranal (volatile oil that gives characteristic odor and aroma). The heat-sensitive volatile and aroma-yielding compounds of saffron can be more preserved using freeze drying in comparison with other conventional drying methods. In this study the freeze-drying characteristics of saffron was determined experimentally. The drying kinetics data were fitted to 10 different empirical diffusion drying models from literature to find the best model that represents the weight loss of saffron during the freeze drying. Among the models tested in this study, the Page model was found to be the best model in representing the drying kinetics of saffron during the freeze drying. Effective diffusivity found as 1.62x10(-11)m(2)/s. Practical ApplicationsSaffron, which has been intensively used for flavoring and coloring foods, dying textile and medical purposes since ancient times, is the most precious and expensive agricultural product in the world. Freeze drying, which is both slow and expensive, is the method of separation for high market value products. It has been shown that freeze drying can be used for dehydration of saffron with minimum safranal (main aroma component) and crocin (coloring agent) loss. High cost of freeze drying of saffron can be compensated by minimum loss of safranal and crocin contents in the final product. It is crucial to know the drying kinetics of saffron to determine the drying time under certain conditions. In this work, the freeze-drying kinetics of saffron were studied and the best empirical model that represents the weight loss of saffron during the freeze drying and effective diffusivity were determined. |
BibTeX:
@article{Acar2015,
author = {Acar, B. and Sadikoglu, H. and Doymaz, I.},
title = {Freeze-drying Kinetics and Diffusion Modeling of Saffron (crocus Sativus L.)},
journal = {Journal of Food Processing and Preservation},
year = {2015},
volume = {39},
number = {2},
pages = {142--149},
doi = {10.1111/jfpp.12214}
}
|
| Gumusay OA, Borazan AA, Ercal N and Demirkol O (2015), "Drying effects on the antioxidant properties of tomatoes and ginger", Food Chemistry., April, 2015. Vol. 173, pp. 156-162. |
| Abstract: In this study, the effects of four different drying processes, sun drying (SD), oven drying (OD), vacuum oven drying (VOD) and freeze drying (FD) for tomatoes (Solanum lycopersicum) and ginger (Zingiber officinale) in terms of thiolic and phenolic contents have been studied. Thiol content, total phenolic content (TPC), ascorbic acid (AA) content, and cupric ion reducing antioxidant capacity (CUPRAC) were determined in fresh and dried samples. Glutathione (GSH) and cysteine (Cys) were determined as the thiol contents of tomatoes and ginger. Significant losses were observed in the contents of TPC, AA, GSH and Cys and CUPRAC values in all samples that were dried using the thermal method. There was a statistically significant difference in the losses of the TPC, AA, and thiol contents between the use of thermal drying and freeze drying (except Cys in tomatoes) methods. Freeze dried tomato and ginger samples have been found to have better antioxidant properties. (C) 2014 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Gumusay2015,
author = {Gumusay, O. A. and Borazan, A. A. and Ercal, N. and Demirkol, O.},
title = {Drying effects on the antioxidant properties of tomatoes and ginger},
journal = {Food Chemistry},
year = {2015},
volume = {173},
pages = {156--162},
doi = {10.1016/j.foodchem.2014.09.162}
}
|
| Isleroglu H, Kemerli T and Kaymak-Ertekin F ({2015}), "Effect of Steam-Assisted Hybrid Cooking on Textural Quality Characteristics, Cooking Loss, and Free Moisture Content of Beef", INTERNATIONAL JOURNAL OF FOOD PROPERTIES., FEB 1, {2015}. Vol. {18}({2}), pp. 403-414. |
| Abstract: Semitendinosus muscles were cooked in a steam-assisted hybrid oven and
also convection ovens at three different oven temperatures (180, 210, and 240 degrees C) until three different end point temperatures [65 degrees C (medium-rare), 72 degrees C (medium), 80 degrees C (medium-well)] were reached. Textural properties of cooked beef were investigated by the Warner Bratzler shear test and texture profile analysis. Cooking loss and free moisture content of muscle tissue was determined for each cooking condition. In addition, sensory analysis was carried out in order to compare with the instrumental results and correlations between instrumental texture parameters and sensory results. Steam-assisted hybrid oven cooking of beef resulted in a tougher texture, higher cooking loss, and lower free moisture content than convection cooking. High correlation coefficients (r(2) > 0.70) were observed between instrumental texture measurements and sensory results for all ovens, especially in terms of tenderness. The free moisture content and adhesiveness values were also correlated well with juiciness (r(2) > 0.70) for all oven types. |
BibTeX:
@article{Isleroglu2015,
author = {Isleroglu, Hilal and Kemerli, Tansel and Kaymak-Ertekin, Figen},
title = {Effect of Steam-Assisted Hybrid Cooking on Textural Quality Characteristics, Cooking Loss, and Free Moisture Content of Beef},
journal = {INTERNATIONAL JOURNAL OF FOOD PROPERTIES},
year = {2015},
volume = {18},
number = {2},
pages = {403--414},
doi = {10.1080/10942912.2013.833219}
}
|
| Gulsuner HU, Gengec NA, Kilinc M, Erbil HY and Tekinay AB ({2015}), "Osteoselection supported by phase separated polymer blend films", JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A., JAN, {2015}. Vol. {103}({1}), pp. 154-161. |
| Abstract: The instability of implants after placement inside the body is one of
the main obstacles to clinically succeed in periodontal and orthopedic applications. Adherence of fibroblasts instead of osteoblasts to implant surfaces usually results in formation of scar tissue and loss of the implant. Thus, selective bioadhesivity of osteoblasts is a desired characteristic for implant materials. In this study, we developed osteoselective and biofriendly polymeric thin films fabricated with a simple phase separation method using either homopolymers or various blends of homopolymers and copolymers. As adhesive and proliferative features of cells are highly dependent on the physicochemical properties of the surfaces, substrates with distinct chemical heterogeneity, wettability, and surface topography were developed and assessed for their osteoselective characteristics. Surface characterizations of the fabricated polymer thin films were performed with optical microscopy and SEM, their wettabilities were determined by contact angle measurements, and their surface roughness was measured by profilometry. Long-term adhesion behaviors of cells to polymer thin films were determined by F-actin staining of Saos-2 osteoblasts, and human gingival fibroblasts, HGFs, and their morphologies were observed by SEM imaging. The biocompatibility of the surfaces was also examined through cell viability assay. Our results showed that heterogeneous polypropylene polyethylene/polystyrene surfaces can govern Saos-2 and HGF attachment and organization. Selective adhesion of Saos-2 osteoblasts and inhibited adhesion of HGF cells were achieved on micro-structured and hydrophobic surfaces. This work paves the way for better control of cellular behaviors for adjustment of cell material interactions. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 154-161, 2015. |
BibTeX:
@article{Gulsuner2015,
author = {Gulsuner, Hilal Unal and Gengec, Nevin Atalay and Kilinc, Murat and Erbil, H. Yildirim and Tekinay, Ayse B.},
title = {Osteoselection supported by phase separated polymer blend films},
journal = {JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A},
year = {2015},
volume = {103},
number = {1},
pages = {154--161},
doi = {{10.1002/jbm.a.35164}}
}
|
| Tarlak F, Sadikoglu H and Cakir T (2014), "The role of flexibility and optimality in the prediction of intracellular fluxes of microbial central carbon metabolism", Molecular Biosystems. Vol. 10(9), pp. 2459-2465. |
| Abstract: Prediction of intracellular metabolic fluxes based on optimal biomass assumption is a well-known computational approach. While there has been a significant emphasis on the optimality, cellular flexibility, the co-occurrence of suboptimal flux distributions in a microbial population, has hardly been considered in the related computational methods. We have implemented a flexibility-incorporated optimization framework to calculate intracellular fluxes based on a few extracellular measurement constraints. Taking into account slightly suboptimal flux distributions together with a dual-optimality framework (maximization of the growth rate followed by the minimization of the total enzyme amount) we were able to show the positive effect of incorporating flexibility and minimal enzyme consumption on the better prediction of intracellular fluxes of central carbon metabolism of two microorganisms: E. coli and S. cerevisiae. |
BibTeX:
@article{Tarlak2014,
author = {Tarlak, F. and Sadikoglu, H. and Cakir, T.},
title = {The role of flexibility and optimality in the prediction of intracellular fluxes of microbial central carbon metabolism},
journal = {Molecular Biosystems},
year = {2014},
volume = {10},
number = {9},
pages = {2459--2465},
doi = {10.1039/c4mb00117f}
}
|
| Pleissner D, Lam WC, Han W, Lau KY, Cheung LC, Lee MW, Lei HM, Lo KY, Ng WY, Sun Z, Melikoglu M and Lin CSK (2014), "Fermentative Polyhydroxybutyrate Production from a Novel Feedstock Derived from Bakery Waste", Biomed Research International. , pp. 819474. |
| Abstract: In this study, Halomonas boliviensis was cultivated on bakery waste hydrolysate and seawater in batch and fed-batch cultures for polyhydroxybutyrate (PHB) production. Results demonstrated that bakery waste hydrolysate and seawater could be efficiently utilized by Halomonas boliviensis while PHB contents between 10 and 30% (w/w) were obtained. Furthermore, three methods for bakery waste hydrolysis were investigated for feedstock preparation. These include: (1) use of crude enzyme extracts from Aspergillus awamori, (2) Aspergillus awamori solid mashes, and (3) commercial glucoamylase. In the first method, the resultant free amino nitrogen (FAN) concentration in hydrolysates was 150 and 250mg L-1 after 20 hours at enzyme-to-solid ratios of 6.9 and 13.1 U g(-1), respectively. In both cases, the final glucose concentration was around 130-150 g L-1. In the second method, the resultant FAN and glucose concentrations were 250 mg L-1 and 150 g L-1, respectively. In the third method, highest glucose and lowest FAN concentrations of 170-200 g L-1 and 100 mg L-1, respectively, were obtained in hydrolysates after only 5 hours. The present work has generated promising information contributing to the sustainable production of bioplastic using bakery waste hydrolysate. |
BibTeX:
@article{Pleissner2014,
author = {Pleissner, D. and Lam, W. C. and Han, W. and Lau, K. Y. and Cheung, L. C. and Lee, M. W. and Lei, H. M. and Lo, K. Y. and Ng, W. Y. and Sun, Z. and Melikoglu, M. and Lin, C. S. K.},
title = {Fermentative Polyhydroxybutyrate Production from a Novel Feedstock Derived from Bakery Waste},
journal = {Biomed Research International},
year = {2014},
pages = {819474},
doi = {10.1155/2014/819474}
}
|
| Depardieu M, Janot R, Sanchez C, Bentaleb A, Gervais C, Birot M, Demir-Cakan R, Backov R and Morcrette M (2014), "Carbonaceous multiscale-cellular foams as novel electrodes for stable, efficient lithium-sulfur batteries", Rsc Advances. Vol. 4(46), pp. 23971-23976. |
| Abstract: Porous carbon foams were prepared by pyrolysis of a phenolic resin by a dual template approach using silica monoliths as hard templates and triblock copolymers as soft templating agents. A macroporosity of 50-80% arose from the Si(HIPE) hard template, while the soft template generated micro-or meso-porosity according to the operating procedure. The final materials exhibited a BET specific surface area of 400-900 m(2) g(-1), depending on whether non-ionic surfactants were used during the synthesis; moreover, their performances as Li-sulfide battery positive electrodes were investigated. We determined that the novel 2P5HF carbon foam presents more than 800 mA h g(-1) (150 mA h cm(-3)) of remnant capacity after 50 cycles, an unprecedented performance. |
BibTeX:
@article{Depardieu2014,
author = {Depardieu, M. and Janot, R. and Sanchez, C. and Bentaleb, A. and Gervais, C. and Birot, M. and Demir-Cakan, R. and Backov, R. and Morcrette, M.},
title = {Carbonaceous multiscale-cellular foams as novel electrodes for stable, efficient lithium-sulfur batteries},
journal = {Rsc Advances},
year = {2014},
volume = {4},
number = {46},
pages = {23971--23976},
doi = {10.1039/c4ra03110e}
}
|
| Demir-Cakan R, Morcrette M, Leriche JB and Tarascon JM (2014), "An aqueous electrolyte rechargeable Li-ion/polysulfide battery", Journal of Materials Chemistry A. Vol. 2(24), pp. 9025-9029. |
| Abstract: In spite of great research efforts on Li-S batteries in aprotic organic electrolytes, there have been very few studies showing the potential application of this system in aqueous electrolyte. Herein, we explore this option and report on a cheaper and safer new aqueous system coupling a well-known cathode material in Li-ion batteries (i.e. LiMn2O4) with a dissolved polysulfide anode. In comparison with classical Li-S batteries containing aprotic organic solvents, the aqueous electrolyte offers a stable cycling profile over 100 cycles with faster C-regime. |
BibTeX:
@article{Demir-Cakan2014,
author = {Demir-Cakan, R. and Morcrette, M. and Leriche, J. B. and Tarascon, J. M.},
title = {An aqueous electrolyte rechargeable Li-ion/polysulfide battery},
journal = {Journal of Materials Chemistry A},
year = {2014},
volume = {2},
number = {24},
pages = {9025--9029},
doi = {10.1039/c4ta01308e}
}
|
| Erbil HY (2014), "The debate on the dependence of apparent contact angles on drop contact area or three-phase contact line: A review", Surface Science Reports., December, 2014. Vol. 69(4), pp. 325-365. |
| Abstract: A sessile drop is an isolated drop which has been deposited on a solid substrate where the wetted area is limited by the three-phase contact line and characterized by contact angle, contact radius and drop height. Although, wetting has been studied using contact angles of drops on solids for more than 200 years, the question remains unanswered: Is),vetting of a rough and chemically heterogeneous surface controlled by the interactions within the solid/liquid contact area beneath the droplet or only at the three-phase contact line? After the publications of Pease in 1945. Extrand in 1997, 2003 and Gao and McCarthy in 2007 and 2009, it was proposed that advancing, receding contact angles, and contact angle hysteresis of rough and chemically heterogeneous surfaces are determined by interactions of the liquid and the solid at the three-phase contact line alone and the interfacial area within the contact perimeter is irrelevant. As a consequence of this statement, the well-known Wenzel (1934) and Cassie (1945) equations which were derived using the contact area approach are proposed to be invalid and should be abandoned. A hot debate started in the field of surface science after 2007, between the three-phase contact line and interfacial contact area approach defenders. This paper presents a review of the published articles on contact angles and summarizes the views of the both sides. After presenting a brief history of the contact angles and their measurement methods, we discussed the basic contact angle theory and applications of contact angles on the characterization of flat, rough and micropatterned superhydrophobic surfaces. The weak and strong sides of both three-phase contact line and contact area approaches were discussed in detail and some practical conclusions were drawn. (C) 2014 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Erbil2014,
author = {Erbil, H. Y.},
title = {The debate on the dependence of apparent contact angles on drop contact area or three-phase contact line: A review},
journal = {Surface Science Reports},
year = {2014},
volume = {69},
number = {4},
pages = {325--365},
doi = {10.1016/j.surfrep.2014.09.001}
}
|
| Doganci MD, Cavusoglu S, Oksuz M and Erbil HY (2014), "Effect of surface free energy to control the deposit morphology during evaporation of graphite/SDS dispersion drops", Colloids and Surfaces A-physicochemical and Engineering Aspects., November, 2014. Vol. 461, pp. 310-322. |
| Abstract: Uniform spherical cap shaped graphite/sodium dodecyl sulfate surfactant (SDS) micro-deposits were formed after the complete evaporation of aqueous graphite/SDS dispersion drops containing 2 and 4 mM of SDS and 10, 20, 40, 60, 80 and 110 mg/ml graphite micro-powder on hydrophobic surfaces such as Teflon-FEP and tridecafluorooctyltriethoxysilane coated glass slides. The shapes and sizes of the graphite/SDS micro-deposits were also investigated on polypropylene, polymethyl methacrylate, and polyvinyl alcohol surfaces. A good linear relationship was found between the surface free energy of the substrates and the diameters of the graphite/SDS deposits. The volumes and heights of the spherical cap shaped deposits can be controlled by varying the substrate surface free energy, concentration of graphite and SDS in the dispersion drop. SDS adsorption on graphite resulted in better surface packing of the microparticles on hydrophobic substrates. Effect of particle size on the deposit shape and size was also investigated by comparing SDS/graphite deposits formed from carbon microparticles with SDS/fullerene deposits formed from carbon nanoparticles. In addition, "stick-slip" motion of a (graphite + water) dispersion droplet on a polypropylene surface was investigated by the model proposed by Shanahan et al. and the potential energy barrier was calculated to be small for graphite microparticles on this surface. (C) 2014 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Doganci2014,
author = {Doganci, M. D. and Cavusoglu, S. and Oksuz, M. and Erbil, H. Y.},
title = {Effect of surface free energy to control the deposit morphology during evaporation of graphite/SDS dispersion drops},
journal = {Colloids and Surfaces A-physicochemical and Engineering Aspects},
year = {2014},
volume = {461},
pages = {310--322},
doi = {10.1016/j.colsurfa.2014.08.004}
}
|
| Melikoglu M (2014), "Shale gas: Analysis of its role in the global energy market", Renewable & Sustainable Energy Reviews., September, 2014. Vol. 37, pp. 460-468. |
| Abstract: Shale gas revolution that took place in the United States at the beginning of the 21st century has still been shaping our global fossil fuel market. In 2012, the U.S. has surpassed Russia in natural gas production for the first time since 1982. At the same year, annual average U.S. Henry hub natural gas spot price decreased to 2.75 per million BTU, which was 8.69 per million BTU in 2005. In 2013, proved shale gas reserves of the world is estimated at nearly 2.7 trillion cubic metres (tcm) and unproved resources at staggering 203.9 tcm. As a result, there is a global rush to develop most of this resource as possible. However, shale gas is no miracle fuel. It has been suggested that its effects on the environment could be worse than conventional natural gas. Fugitive methane emissions, groundwater pollution, and increased seismicity are amongst the most important potential environmental side effects. There is also concern about the accuracy of resource potential estimations due to lack of data and specifically designed shale gas reservoir models. Nonetheless, the analysis in this study clearly showed that without developing global shale gas resources we have to consume 66% of our proved natural gas reserves to supply the demand till 2040. This would make most of the world natural gas importers, and rules of economy dictate that limited supply and increasing demand would skyrocket natural gas prices. Therefore, shale gas resource development is not an option but a must for the continuance of our global energy market and economy. (C) 2014 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Melikoglu2014,
author = {Melikoglu, M.},
title = {Shale gas: Analysis of its role in the global energy market},
journal = {Renewable & Sustainable Energy Reviews},
year = {2014},
volume = {37},
pages = {460--468},
doi = {10.1016/j.rser.2014.05.002}
}
|
| Cengiz U and Erbil HY (2014), "Perfluoromethacrylate-styrene statistical copolymers synthesized in CO2-expanded monomers", Colloid and Polymer Science., September, 2014. Vol. 292(9), pp. 2207-2215. |
| Abstract: Statistical copolymers of perfluoroalkyl ethyl methacrylate (Zonyl-TM) and styrene (S) were synthesized in CO2-expanded monomer medium at a low initial pressure of 25 MPa. Different Zonyl-TM/S feed ratios were used during copolymerizations, and it was determined that the increase in the Zonyl-TM content and decrease of the CO2 amount in the comonomer feed resulted in a decrease of the molecular weights of copolymers due to earlier precipitation of copolymers giving shorter chains. The cloudy CO2-expanded liquid monomer phase was found to be the main loci of copolymerization. In addition, the increase in the Zonyl-TM feed ratio resulted in an increase in the critical degree of the polymerization time (J (crit)) as the time when the copolymer chains start to precipitate. The higher the Zonyl-TM content used in the feed, the higher the J (crit) time and the lower the weight-average molecular weight (M (w)) of the copolymer obtained. Thermal analysis results of the copolymer indicated that the copolymers are stable up to 387-403 A degrees C. |
BibTeX:
@article{Cengiz2014,
author = {Cengiz, U. and Erbil, H. Y.},
title = {Perfluoromethacrylate-styrene statistical copolymers synthesized in CO2-expanded monomers},
journal = {Colloid and Polymer Science},
year = {2014},
volume = {292},
number = {9},
pages = {2207--2215},
doi = {10.1007/s00396-014-3250-8}
}
|
| Isleroglu H, Kemerli T, Ozdestan O, Uren A and Kaymak-Ertekin F ({2014}), "Effect of oven cooking method on formation of heterocyclic amines and quality characteristics of chicken patties: Steam-assisted hybrid oven versus convection ovens", POULTRY SCIENCE., SEP, {2014}. Vol. {93}({9}), pp. 2296-2303. |
| Abstract: The aim of this study was to evaluate effect of steam-assisted hybrid
oven cooking method in comparison with convection ovens (natural and forced) on quality characteristics (color, hardness, cooking loss, soluble protein content, fat retention, and formation of heterocyclic aromatic amines) of chicken patties. The cooking experiments of chicken patties (n = 648) were conducted at oven temperatures of 180, 210, and 240 degrees C until 3 different end point temperatures (75, 90, and 100 degrees C) were reached. Steam-assisted hybrid oven cooking enabled faster cooking than convection ovens and resulted in chicken patties having lower a* and higher L* value, lower hardness, lower fat, and soluble protein content (P < 0.05), and higher cooking loss than convection ovens. Steam-assisted hybrid oven could reduce the formation of heterocyclic aromatic amines that have mutagenic and carcinogenic effects on humans. |
BibTeX:
@article{Isleroglu2014,
author = {Isleroglu, Hilal and Kemerli, Tansel and Ozdestan, Ozgul and Uren, Ali and Kaymak-Ertekin, Figen},
title = {Effect of oven cooking method on formation of heterocyclic amines and quality characteristics of chicken patties: Steam-assisted hybrid oven versus convection ovens},
journal = {POULTRY SCIENCE},
year = {2014},
volume = {93},
number = {9},
pages = {2296--2303},
doi = {10.3382/ps.2013-03552}
}
|
| Ergan BT and Bayramoglu M (2014), "Investigation of the Microwave Effect: A New Approach for the Solvent Effect on the Microwave-Assisted Decomposition Reaction of 2,2 '-Azobis(isobutyronitrile)", Industrial & Engineering Chemistry Research., August, 2014. Vol. 53(33), pp. 13016-13022. |
| Abstract: In this work, the effect of the solvent type on microwave (MW)-assisted decomposition of 2,2'-azobis(isobutyronitrile) was investigated by online monitoring of the reaction kinetics in various solvents: n-butanol, dimethyl sulfoxide, dimethylformamide, and n-propanol. The study showed that MW irradiation accelerates the reaction rates, but it does not affect the kinetic law (first order) and mechanism of the reaction. Furthermore, the Arrhenius parameters were found to be higher than their thermal counterparts, depending on the MW power density (P) as well as to the solvent type. On the other hand, two new properties were proposed to investigate the solvent/MW effects: a solvent property (S) defined by means of Hansen solubility parameters and the relaxation time of the solvent (tau). According to experimental results, solvents with high S and with an optimum tau value are favorable for an enhanced MW effect on chemical reaction kinetics, pointing to specific molecular structures for solvent candidates. |
BibTeX:
@article{Ergan2014,
author = {Ergan, B. T. and Bayramoglu, M.},
title = {Investigation of the Microwave Effect: A New Approach for the Solvent Effect on the Microwave-Assisted Decomposition Reaction of 2,2 '-Azobis(isobutyronitrile)},
journal = {Industrial & Engineering Chemistry Research},
year = {2014},
volume = {53},
number = {33},
pages = {13016--13022},
doi = {10.1021/ie5021359}
}
|
| Korkut I and Bayramoglu M ({2014}), "Various aspects of ultrasound assisted emulsion polymerization process", ULTRASONICS SONOCHEMISTRY., JUL, {2014}. Vol. {21}({4}), pp. 1592-1599. |
| Abstract: In this paper, the effects of ultrasonic (US) power, pulse ratio, probe
area and recipe composition were investigated on two process responses namely, monomer (methyl methacrylate, MMA) conversion and electrical energy consumption per mass of product polymer (PMMA). Pulsed mode US is more suitable than continuous mode US for emulsion polymerization. The probe (tip) area has little effect on the yield of polymerization when comparing 19 and 13 mm probes, 13 mm probe performing slightly better for high conversion levels. Meanwhile, large probe area is beneficial for high conversion efficiency of electric energy to US energy as well as for high radical generation yield per energy consumed. The conversion increased slightly and electrical energy consumption decreased substantially by using a recipe with high SDS and monomer concentrations. Conclusions presented in this paper may be useful for scale-up of US assisted emulsion polymerization. (C) 2014 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Korkut2014,
author = {Korkut, Ibrahim and Bayramoglu, Mahmut},
title = {Various aspects of ultrasound assisted emulsion polymerization process},
journal = {ULTRASONICS SONOCHEMISTRY},
year = {2014},
volume = {21},
number = {4},
pages = {1592--1599},
doi = {{10.1016/j.ultsonch.2013.12.028}}
}
|
| Kayhan O and Hastaoglu MA (2014), "Modeling of Stratospheric Balloon Using Transport Phenomena and Gas Compress-Release System", Journal of Thermophysics and Heat Transfer., July, 2014. Vol. 28(3), pp. 534-541. |
| Abstract: For high-altitude zero-pressure balloons, a model has been developed based on balloon dynamics and heat and mass transfer aspects, which has not been studied in the same model before. It was combined with a velocity-control mechanism. The behavior of the balloon, and especially the lift gas mass transfer mechanism, has been investigated for the first time. The model was validated using NASA test flight data. The variation of the flight time with the amounts of initial and stored gas, total weight of the balloon, and its payload is analyzed. The effects of solar radiation absorptivity, infrared emissivity, and other thermophysical properties are discussed in detail. The effects of the mass transfer coefficient on mass transfer rate and flight time are investigated. It was found that, with the sacrificial flight gas compress-release model, it is possible to place the balloon at its orbit without using ballast and extend the flight time more than currently available. |
BibTeX:
@article{Kayhan2014,
author = {Kayhan, O. and Hastaoglu, M. A.},
title = {Modeling of Stratospheric Balloon Using Transport Phenomena and Gas Compress-Release System},
journal = {Journal of Thermophysics and Heat Transfer},
year = {2014},
volume = {28},
number = {3},
pages = {534--541},
doi = {10.2514/1.T4271}
}
|
| Ozbay S and Erbil HY (2014), "Solution copolymerization of perfluoroalkyl ethyl methacrylate with methyl methacrylate and butyl acrylate: Synthesis and surface properties", Colloids and Surfaces A-physicochemical and Engineering Aspects., June, 2014. Vol. 452, pp. 9-17. |
| Abstract: Random copolymers of perfluoroalkyl ethyl methacrylate (Zonyl-TM), methyl methacrylate (MMA) and butyl acrylate (BA) monomers were synthesized by free radical copolymerization in toluene/methyl ethyl ketone solvent mixture. Batch polymerizations have been performed using different monomer feed compositions with high conversions. Molecular weights of the copolymers were determined by GPC and intrinsic viscosity measurements. Chemical structures of the copolymers were characterized by H-1-NMR and T-g values were determined by DSC. Thin films were prepared by dip coating glass slides into copolymer solutions and water and oil repellence, surface free energies were measured by contact angle measurement. Mainly, the effects of addition of BA and Zonyl-TM on the structure and surface properties of the copolymers were investigated. It was found that the T-g value of copolymers decreased considerably by the addition of Zonyl-TM and BA into the feed due to the internal plasticizing effects of both monomers. Water contact angles of the copolymers were increased from 71 degrees to 119 degrees with the increase of the Zonyl-TM content. Addition of BA was found to be more effective than MMA to introduce hydrophobicity onto the surface. Small amount of Zonyl-TM incorporation was enough to decrease the surface free energy (SFE) of copolymer film to a very low value of 9.7 mJ/m(2). In addition, the increase in the Zonyl-TM and BA contents resulted in an increase in the oil repellence of copolymer surfaces which was measured by the contact angles of octane, decane, tetradecane and hexadecane drops. (C) 2014 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Ozbay2014,
author = {Ozbay, S. and Erbil, H. Y.},
title = {Solution copolymerization of perfluoroalkyl ethyl methacrylate with methyl methacrylate and butyl acrylate: Synthesis and surface properties},
journal = {Colloids and Surfaces A-physicochemical and Engineering Aspects},
year = {2014},
volume = {452},
pages = {9--17},
doi = {10.1016/j.colsurfa.2014.03.054}
}
|
| Oksuz M and Erbil HY (2014), "Comments on the Energy Barrier Calculations during "Stick-Slip" Behavior of Evaporating Droplets Containing Nanoparticles", Journal of Physical Chemistry C., May, 2014. Vol. 118(17), pp. 9228-9238. |
| Abstract: The application of three different potential energy barrier equations which were developed by Shanahan and co-workers for the "stick-slip" motion of droplets during evaporation of nanosuspensions to experimental data was investigated, and the results were compared. In theory, these potential energy barrier equations were assumed to be equivalent to each other, and thus the excess Gibbs free energy calculation results should be very close to each other. However, the calculated potential energy barrier results were found to be much different from each other when these equations were applied to two recently published experimental data. The details of the calculation procedures and these differences in the results are discussed, and eight new slightly modified equations are given in two sets to obtain reliable, comparable and easily plotted potential energy barrier values. reasons for more reliable, comparable and easily plotted potential energy barrier values. |
BibTeX:
@article{Oksuz2014,
author = {Oksuz, M. and Erbil, H. Y.},
title = {Comments on the Energy Barrier Calculations during "Stick-Slip" Behavior of Evaporating Droplets Containing Nanoparticles},
journal = {Journal of Physical Chemistry C},
year = {2014},
volume = {118},
number = {17},
pages = {9228--9238},
doi = {10.1021/jp5010083}
}
|
| Oksuz M and Erbil HY ({2014}), "Comments on the Energy Barrier Calculations during ``Stick-Slip'' Behavior of Evaporating Droplets Containing Nanoparticles", JOURNAL OF PHYSICAL CHEMISTRY C., MAY 1, {2014}. Vol. {118}({17}), pp. 9228-9238. |
| Abstract: The application of three different potential energy barrier equations
which were developed by Shanahan and co-workers for the ``stick-slip'' motion of droplets during evaporation of nanosuspensions to experimental data was investigated, and the results were compared. In theory, these potential energy barrier equations were assumed to be equivalent to each other, and thus the excess Gibbs free energy calculation results should be very close to each other. However, the calculated potential energy barrier results were found to be much different from each other when these equations were applied to two recently published experimental data. The details of the calculation procedures and these differences in the results are discussed, and eight new slightly modified equations are given in two sets to obtain reliable, comparable and easily plotted potential energy barrier values. reasons for more reliable, comparable and easily plotted potential energy barrier values. |
BibTeX:
@article{Oksuz2014a,
author = {Oksuz, Melik and Erbil, H. Yildirim},
title = {Comments on the Energy Barrier Calculations during ``Stick-Slip'' Behavior of Evaporating Droplets Containing Nanoparticles},
journal = {JOURNAL OF PHYSICAL CHEMISTRY C},
year = {2014},
volume = {118},
number = {17},
pages = {9228--9238},
doi = {{10.1021/jp5010083}}
}
|
| Melikoglu M (2014), "Demand forecast for road transportation fuels including gasoline, diesel, LPG, bioethanol and biodiesel for Turkey between 2013 and 2023", Renewable Energy., April, 2014. Vol. 64, pp. 164-171. |
| Abstract: In Turkey, more than 90% of passengers and goods are transported by roads. In order to flow this immense traffic nearly 2.7 million m(3) of gasoline, 11.5 million m(3) of diesel, and 5.2 million m(3) of liquefied petroleum gas (LPG) was consumed in 2011. Starting from 2013, Turkey plans to blend biofuels to gasoline and diesel gradually reaching to 10% (volume) by 2020. Turkey's economy has been growing at unprecedented rates since 2003. As a result, both diesel and LPG consumption reached to record levels. Yet, gasoline demand decreased almost linearly in the same period. Accordingly, forecasting road transportation fuel demand becomes more difficult and yet more important than ever before. Gasoline, diesel, LPG, bioethanol and biodiesel demand has been forecast for the first time in this study using semi-empirical models in the view of Turkey's Vision 2023 goals, Energy Market Regulatory Authority targets, and European Union directives. The models suggested that in 2023, annual gasoline consumption in Turkey could decrease below 2.0 million m(3), whereas, diesel and LPG consumption could rise to 16.4 and 8.8 million m(3), respectively. Consequently, 0.3 million m(3) of bioethanol and 1.4 million m(3) biodiesel could be required to fulfil the official targets in 2023. (C) 2013 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Melikoglu2014a,
author = {Melikoglu, M.},
title = {Demand forecast for road transportation fuels including gasoline, diesel, LPG, bioethanol and biodiesel for Turkey between 2013 and 2023},
journal = {Renewable Energy},
year = {2014},
volume = {64},
pages = {164--171},
doi = {10.1016/j.renene.2013.11.009}
}
|
| Can OT and Bayramoglu M (2014), "A Comparative Study on the Structure-Performance Relationships of Chemically and Electrochemically Coagulated Al(OH)(3) Flocs", Industrial & Engineering Chemistry Research., March, 2014. Vol. 53(9), pp. 3528-3538. |
| Abstract: In this paper, various physical and chemical characteristics of electro-coagulated (ECC) and chemical-coagulated (CC) aluminum hydroxide flocs were explored comparatively in the context of their impacts on the pollutant removal performance of the processes. First, the sedimentation rate, floc size and zeta potential of the flocs at different pH values were measured in solution. Furthermore, flocs dried at 105 degrees C were characterized by various techniques such as TGA,FT-IR, SEM, XRD, BET and XPS as well as by chemical analysis. It was found that ECC flocs were bigger in size, faster in sedimentation and better pressed, while they had higher BET area, less water and higher isoelectric pH than CC flocs. Furthermore, pollutant removal tests using various chemicals such as benzoquinone, hydroquinone and a reactive dye showed that ECC flocs outperformed CC flocs, due to superior physical-chemical characteristics. |
BibTeX:
@article{Can2014,
author = {Can, O. T. and Bayramoglu, M.},
title = {A Comparative Study on the Structure-Performance Relationships of Chemically and Electrochemically Coagulated Al(OH)(3) Flocs},
journal = {Industrial & Engineering Chemistry Research},
year = {2014},
volume = {53},
number = {9},
pages = {3528--3538},
doi = {10.1021/ie402789w}
}
|
| Cengiz U and Erbil HY ({2014}), "Superhydrophobic perfluoropolymer surfaces having heterogeneous roughness created by dip-coating from solutions containing a nonsolvent", APPLIED SURFACE SCIENCE., FEB 15, {2014}. Vol. {292}, pp. 591-597. |
| Abstract: Superhydrophobic and oleophobic rough copolymer surfaces containing
micro- and nano-hierarchical ball-like islands having diameters between 100 nm and 7 mu m were formed using styrene-perfluoromethacrylate random copolymers which were dip-coated on glass slides from THF and MEK mixture containing methanol as nonsolvent. These copolymers were synthesized in a CO2-expanded monomer medium at 250 bar pressure and 80 degrees C. The sizes of the micro-islands can be controlled by varying the copolymer composition; and the degree of phase separation by adjusting the solvent/non-solvent ratio. Flat and lotus-like hierarchical surfaces of the copolymers were characterized using contact angle measurements and SEM. The increase in the perfluoromethacrylate content of the flat copolymers resulted in a decrease of the total surface free energy of the flat copolymer surfaces from 18.3 down to 14.2 mJ/m(2). The increase in the methanol non-solvent fraction resulted in decrease of the micro-island diameter from 7 mu m down to 100 nm and the water contact angle increased from 117 degrees up to 160 degrees and hexadecane from 65 degrees up to 90 degrees. (C) 2013 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Cengiz2014b,
author = {Cengiz, Ugur and Erbil, H. Yildirim},
title = {Superhydrophobic perfluoropolymer surfaces having heterogeneous roughness created by dip-coating from solutions containing a nonsolvent},
journal = {APPLIED SURFACE SCIENCE},
year = {2014},
volume = {292},
pages = {591--597},
doi = {{10.1016/j.apsusc.2013.12.013}}
}
|
| Gengec NA, Gulsuner HU, Erbil HY and Tekinay AB (2014), "Selective adsorption of L1210 leukemia cells/human leukocytes on micropatterned surfaces prepared from polystyrene/polypropylene-polyethylene blends", Colloids and Surfaces B-biointerfaces., January, 2014. Vol. 113, pp. 403-411. |
| Abstract: The objective of this study is to prepare polymeric surfaces which will adsorb L1210 leukemia cells selectively more than that of healthy human leukocytes in order to develop new treatment options for people with leukemia. Chemically heterogeneous and micropatterned surfaces were formed on round glass slides by dip coating with accompanying phase-separation process where only commercial polymers were used. Surface properties were determined by using optical microscopy, 3D profilometry, SEM and measuring contact angles. Polymer, solvent/nonsolvent types, blend composition and temperature were found to be effective in controlling the dimensions of surface microislands. MIT tests were applied for cell viability performance of these surfaces. Polystyrene/polyethylene-polypropylene blend surfaces were found to show considerable positive selectivity to L1210 leukemia cells where L1210/healthy leukocytes adsorption ratio approached to 9-fold in vitro. Effects of wettability, surface free energy, microisland size geometry on the adsorption performances of L1210/leukocytes pairs are discussed. (C) 2013 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Gengec2014,
author = {Gengec, N. A. and Gulsuner, H. U. and Erbil, H. Y. and Tekinay, A. B.},
title = {Selective adsorption of L1210 leukemia cells/human leukocytes on micropatterned surfaces prepared from polystyrene/polypropylene-polyethylene blends},
journal = {Colloids and Surfaces B-biointerfaces},
year = {2014},
volume = {113},
pages = {403--411},
doi = {10.1016/j.colsurfb.2013.09.040}
}
|
| Cengiz U and Erbil HY (2013), "The lifetime of floating liquid marbles: the influence of particle size and effective surface tension", Soft Matter. Vol. 9(37), pp. 8980-8991. |
| Abstract: In this study, we investigated the factors affecting the lifetime of liquid marbles placed on a glass surface and floating on water It was found that the particle size, surface free energy and hydrophobicity of the encapsulating microparticles determine the effective surface tension and lifetime of a liquid marble floating on water We formed liquid marbles using ultra-hydrophobic poly(perfluoroalkyl ethyl acrylate) powder with three different particle sizes (8 +/- 1, 20 +/- 2 and 60 +/- 5 mu m) and polytetrafluoroethylene powder (7 +/- 2 mu m). It was found that both the effective surface tension and lifetime of a floating liquid marble increased considerably with the decrease in the particle size of the ultra-hydrophobic poly(perfluoroalkyl ethyl acrylate) powder We also determined that a floating liquid marble had a longer lifetime if the water contact angle of the polymer powder was high and its surface free energy was low by comparing the results of two different powders having very close average particle sizes but different hydrophobicities. |
BibTeX:
@article{Cengiz2013a,
author = {Cengiz, U. and Erbil, H. Y.},
title = {The lifetime of floating liquid marbles: the influence of particle size and effective surface tension},
journal = {Soft Matter},
year = {2013},
volume = {9},
number = {37},
pages = {8980--8991},
doi = {10.1039/c3sm51304a}
}
|
| Orkan Ucar I and Erbil HY (2013), "Droplet condensation on polymer surfaces: A review", Turkish Journal of Chemistry. Vol. 37(4), pp. 643-674. |
| Abstract: Dropwise condensation on substrates is an important topic of interest because it plays a crucial role in many scientific applications such as heat transfer, water harvesting from the humid atmosphere, and polymer templating. We focused on droplet condensation on polymer surfaces and briefly summarized the drop condensation studies reported in the last 2 decades and their potential applications. The main topics discussed in this review are water harvesting from dew using radiative cooling; using surfaces synthesized by bio-inspiration; experimental, theoretical, and simulation studies on the growth of breath figures; drop condensation on superhydrophobic surfaces and on self-assembled monolayers; and hexagonal pattern formation on polymers using the breath figures method. This review does not cover dropwise condensation studies in heat transfer phenomena since polymers are rarely used for this purpose due to their low heat transfer coefficients. |
BibTeX:
@article{OrkanUcar2013,
author = {Orkan Ucar, I. and Erbil, H. Y.},
title = {Droplet condensation on polymer surfaces: A review},
journal = {Turkish Journal of Chemistry},
year = {2013},
volume = {37},
number = {4},
pages = {643--674},
doi = {10.3906/kim-1303-26}
}
|
| Kayhan O and Hastaoglu MA (2013), "Control of High Altitude Telecommunication Balloons via Transport Phenomena, Material and Fuell Cell", Proceedings of 6th International Conference on Recent Advances in Space Technologies (rast 2013). , pp. 441-444. |
| Abstract: The behavior of the zero pressure balloons has been numerically investigated by balloon dynamics, heat and mass transfer aspects and combined with a velocity control mechanism. The variation of the flight time with the amounts of initial and stored flight gas, total weight of the balloon and its payload is analyzed. The transient temperature variation of the internal gas during floating at 20 000 m altitude is obtained. The effects of the balloon wall thickness on flight time are investigated. It was found that with the velocity control it is possible to reach target altitude faster and extend the flight time considerably. |
BibTeX:
@article{Kayhan2013,
author = {Kayhan, O. and Hastaoglu, M. A.},
title = {Control of High Altitude Telecommunication Balloons via Transport Phenomena, Material and Fuell Cell},
journal = {Proceedings of 6th International Conference on Recent Advances in Space Technologies (rast 2013)},
year = {2013},
pages = {441--444}
}
|
| Oksuz M, Sadikoglu H and Cakir T (2013), "Sparsity as Cellular Objective to Infer Directed Metabolic Networks from Steady-State Metabolome Data: A Theoretical Analysis", Plos One., December, 2013. Vol. 8(12), pp. e84505. |
| Abstract: Since metabolome data are derived from the underlying metabolic network, reverse engineering of such data to recover the network topology is of wide interest. Lyapunov equation puts a constraint to the link between data and network by coupling the covariance of data with the strength of interactions (Jacobian matrix). This equation, when expressed as a linear set of equations at steady state, constitutes a basis to infer the network structure given the covariance matrix of data. The sparse structure of metabolic networks points to reactions which are active based on minimal enzyme production, hinting at sparsity as a cellular objective. Therefore, for a given covariance matrix, we solved Lyapunov equation to calculate Jacobian matrix by a simultaneous use of minimization of Euclidean norm of residuals and maximization of sparsity (the number of zeros in Jacobian matrix) as objective functions to infer directed small-scale networks from three kingdoms of life (bacteria, fungi, mammalian). The inference performance of the approach was found to be promising, with zero False Positive Rate, and almost one True positive Rate. The effect of missing data on results was additionally analyzed, revealing superiority over similarity-based approaches which infer undirected networks. Our findings suggest that the covariance of metabolome data implies an underlying network with sparsest pattern. The theoretical analysis forms a framework for further investigation of sparsity-based inference of metabolic networks from real metabolome data. |
BibTeX:
@article{Oksuz2013,
author = {Oksuz, M. and Sadikoglu, H. and Cakir, T.},
title = {Sparsity as Cellular Objective to Infer Directed Metabolic Networks from Steady-State Metabolome Data: A Theoretical Analysis},
journal = {Plos One},
year = {2013},
volume = {8},
number = {12},
pages = {e84505},
doi = {10.1371/journal.pone.0084505}
}
|
| Sakin-Yilmazer M, Kemerli T, Isleroglu H, Ozdestan O, Guven G, Uren A and Kaymak-Ertekin F ({2013}), "Baking kinetics of muffins in convection and steam assisted hybrid ovens (baking kinetics of muffin...)", JOURNAL OF FOOD ENGINEERING., DEC, {2013}. Vol. {119}({3}), pp. 483-489. |
| Abstract: Effects of oven type and baking temperature on acrylamide concentration,
surface browning, temperature profiles and drying rates of muffins were investigated. Muffins were baked in convection and steam assisted hybrid ovens at 145, 160 and 175 degrees C for different baking times. For all oven types, the acrylamide concentration of muffins increased with increasing baking time and temperature (p < 0.05). The formation was considered as the first order reaction kinetics except for the lowest baking temperature at natural convection and steam assisted hybrid ovens. The reaction rate constant, k was found to be in the range of 0.027-0.078 (min(-1)). For the forced convection oven, the effect of baking temperature on acrylamide concentration followed the Arrhenius type of equation; with activation energy of 36.35 kJ/mol. The minimum drying rate was observed by the steam assisted hybrid oven, at all conditions. Steam assisted baking resulted in lower acrylamide concentration at all baking temperatures, while providing the average moisture content not significantly different. (C) 2013 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Sakin-Yilmazer2013,
author = {Sakin-Yilmazer, Melike and Kemerli, Tansel and Isleroglu, Hilal and Ozdestan, Ozgul and Guven, Gonul and Uren, Ali and Kaymak-Ertekin, Figen},
title = {Baking kinetics of muffins in convection and steam assisted hybrid ovens (baking kinetics of muffin...)},
journal = {JOURNAL OF FOOD ENGINEERING},
year = {2013},
volume = {119},
number = {3},
pages = {483--489},
doi = {10.1016/j.jfoodeng.2013.06.019}
}
|
| Melikoglu M, Lin CSK and Webb C (2013), "Kinetic studies on the multi-enzyme solution produced via solid state fermentation of waste bread by Aspergillus awamori", Biochemical Engineering Journal., November, 2013. Vol. 80, pp. 76-82. |
| Abstract: The aim of this study was kinetic analysis of the multi-enzyme solution produced from waste bread via solid state fermentation by Aspergillus awamori. It was found that at normal temperature for hydrolysis reactions, 60 degrees C, the activation energies for denaturation of A. awamori glucoamylase, 176.2 kJ/mol, and protease, 149.9 kJ/mol, are much higher than those for catalysis of bread starch, 46.3 kJ/mol, and protein, 36.8 kJ/mol. Kinetic studies showed that glucoamylase and protease in the multi-enzyme solution should have at least two conformations under the two temperature ranges: 30-55 degrees C and 60-70 degrees C. Thermodynamic analysis showed that, deactivation of glucoamylase and protease in the multi-enzyme solution can be reversible between 30 degrees C and 55 degrees C, since Delta S is negative and Delta H is positive. On the other hand, for glucoamylase and protease, both Delta S and Delta H are positive between 60 degrees C and 70 degrees C. This means that the deactivation of both enzymes in the multi-enzyme solution is spontaneous in this temperature range. It was also found that the glucoamylase produced in the solid state fermentation of waste bread is more thermally stable than the protease in the mixture. Consequently, the protease had little or no effect on the stability of the glucoamylase. Furthermore, the half-life of the glucoamylase produced from waste bread pieces was much higher than that produced from wheat flour. This is an important finding because the mode of production, via solid state fermentation, appears to have increased the thermostability of the enzyme significantly. (C) 2013 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Melikoglu2013,
author = {Melikoglu, M. and Lin, C. S. K. and Webb, C.},
title = {Kinetic studies on the multi-enzyme solution produced via solid state fermentation of waste bread by Aspergillus awamori},
journal = {Biochemical Engineering Journal},
year = {2013},
volume = {80},
pages = {76--82},
doi = {10.1016/j.bej.2013.09.016}
}
|
| Uzun D, Dogrusoz M, Mazman M, Bicer E, Avci E, Sener T, Kaypmaz TC and Demir-Cakan R (2013), "Effect of MnO2 coating on layered Li(Li0.1Ni0.3Mn0.5Fe0.1)O-2 cathode material for Li-ion batteries", Solid State Ionics., November, 2013. Vol. 249, pp. 171-176. |
| Abstract: A new nanosized, cobalt free, iron containing and non-toxic layered Li(Li0.1Ni0.3Mn0.5Fe0.1)O-2 cathode material was synthesized by solid-state reaction method and further MnO2 coating procedure was applied to Li(Li0.1Ni0.3Mn0.5Fe0.1)O-2 in order to improve charge/discharge and cycle properties. The effect of MnO2 coating on the capacity and rate capability of cathode active material was described in detail by galvanostatic charge/discharge cycles. Although the initial discharge capacities at a 0.1 C rate were very close at the first discharge as 210 mAh g(-1) for MnO2 coated Li(Li0.1Ni0.3Mn0.5Fe0.1)O-2 and 205 mAh g(-1) for uncoated Li(Li0.1Ni0.3Mn0.5Fe0.1)O-2, respectively, later it was proven that the MnO2 coated cathode active material shows better discharge capacities at faster regimes. The improvement is based on the highly ionic conductive MnO2 coating layer, which suppresses solid electrolyte interface growth during the battery operation. Discharge capacities at 0.1 C rate of uncoated and MnO2 coated layered Li(Li0.1Ni0.3Mn0.5Fe0.1)O-2 cathode materials at the 100th cycle were obtained at 139 and 175 mAh g(-1), respectively. (C) 2013 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Uzun2013,
author = {Uzun, D. and Dogrusoz, M. and Mazman, M. and Bicer, E. and Avci, E. and Sener, T. and Kaypmaz, T. C. and Demir-Cakan, R.},
title = {Effect of MnO2 coating on layered Li(Li0.1Ni0.3Mn0.5Fe0.1)O-2 cathode material for Li-ion batteries},
journal = {Solid State Ionics},
year = {2013},
volume = {249},
pages = {171--176},
doi = {10.1016/j.ssi.2013.08.012}
}
|
| Doganci MD and Erbil HY (2013), "Shape and diameter control of C-60 fullerene micro-stains by evaporation of aqueous SDS-fullerene dispersion drops", Colloids and Surfaces A-physicochemical and Engineering Aspects., September, 2013. Vol. 432, pp. 104-109. |
| Abstract: The effect of the surface free energy of substrates such as glass slide, polymethyl methacrylate, polystyrene, polypropylene and Teflon-FEP was investigated on the shape and diameter of fullerene (C-60) stains which were obtained by evaporation of aqueous sodium dodecyl sulfate/fullerene dispersion drops having different SDS/C-60 fullerene compositions and different drop volumes. It was found that the surface free energy of the substrates was the most important parameter to control the shape and the diameters of the formed SDS/C-60 fullerene deposits and a good linear relationship was obtained between the stain diameter and surface free energy of the substrates. Uniform circular fullerene/SDS deposits were obtained on polystyrene surfaces. (C) 2013 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Doganci2013,
author = {Doganci, M. D. and Erbil, H. Y.},
title = {Shape and diameter control of C-60 fullerene micro-stains by evaporation of aqueous SDS-fullerene dispersion drops},
journal = {Colloids and Surfaces A-physicochemical and Engineering Aspects},
year = {2013},
volume = {432},
pages = {104--109},
doi = {10.1016/j.colsurfa.2013.04.066}
}
|
| Okkay H, Bayramoglu M and Oksuzomer MF (2013), "Ultrasound assisted synthesis of Gd and Nd doped ceria electrolyte for solid oxide fuel cells", Ceramics International., July, 2013. Vol. 39(5), pp. 5219-5225. |
| Abstract: In this study, the ceramic powders of Ce1-xGdxO2-x/2 and Ce1-xNdxO2-x/2 (x=0.05, 0.10, 0.15, 0.20 and 0.25) were synthesized by ultrasound assisted co-precipitation method. The ionic conductivity was studied as a function of dopant concentration over the temperature range of 300-800 degrees C in air, using the impedance spectroscopy. The maximum ionic conductivity, sigma(800 degrees C)=4.01 x 10(-2) Scm(-1) with the activation energy, E-a=0.828 kJmol(-1) and sigma(800 degrees C)=3.80 x 10(-2) Scm(-1) with the activation energy, E-a=0.838 kJmol(-1) were obtained for Ce0.90Gd0.10O1.95 and Ce0.85Nd0.15O1.925 electrolytes, respectively. The average grain size was found to be in the range of 0.3-0.6 mu m for gadolinium doped ceria and 0.2-0.4 mu m for neodymium doped ceria. The uniformly fine crystallite sizes (average 12-13 nm) of the ultrasound assisted prepared powders enabled sintering of the samples into highly dense (over 95%) ceramic pellets at 1200 degrees C (5 degrees C min(-1)) for 6h. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved. |
BibTeX:
@article{Okkay2013,
author = {Okkay, H. and Bayramoglu, M. and Oksuzomer, M. F.},
title = {Ultrasound assisted synthesis of Gd and Nd doped ceria electrolyte for solid oxide fuel cells},
journal = {Ceramics International},
year = {2013},
volume = {39},
number = {5},
pages = {5219--5225},
doi = {10.1016/j.ceramint.2012.12.021}
}
|
| Okkay H, Bayramoglu M and Oksuzomer MF ({2013}), "Ce0.8Sm0.2O1.9 synthesis for solid oxide fuel cell electrolyte by ultrasound assisted co-precipitation method", ULTRASONICS SONOCHEMISTRY., MAY, {2013}. Vol. {20}({3}), pp. 978-983. |
| Abstract: In this study, the synthesis of Ce0.8Sm0.2O1.9 (SDC) solid electrolyte
by the ultrasound assisted co-precipitation method was accomplished to explore the effects of ultrasound power, ultrasound pulse ratio and probe type upon the ionic conductivity of SDC as well as the lattice parameter, the microstructure and the density. Fine powders of uniform crystallite sizes (average 11.70 +/- 0.62 nm) were obtained, needing lower sintering temperature. The SDC powders were successfully sintered to a relative density of over 95% at 1200 degrees C (5 degrees C min(-1)) for 6 h. The micrograph of SDC pellets showed non-agglomerated and well-developed grains with average size of about 200 nm. X-ray diffraction analysis showed that the lattice parameter increased with increasing acoustic intensity and reached a maximum for the 14.94 W cm(-2). Further, a linear relationship was detected between the lattice parameter and the ionic conductivity, inspiring a dopant like effect of US on the electrolyte properties. The highest ionic conductivity as sigma(800 degrees C) = 3.07 x 10(-2) S cm(-1) with an activation energy E-a = 0.871 kJ mol(-1) was obtained with pulsed ultrasound for an acoustic intensity of 14.94W cm(-2), using 19 mm probe and 8:2 pulse ratio. (C) 2012 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Okkay2013b,
author = {Okkay, Hikmet and Bayramoglu, Mahmut and Oksuzomer, M. Faruk},
title = {Ce0.8Sm0.2O1.9 synthesis for solid oxide fuel cell electrolyte by ultrasound assisted co-precipitation method},
journal = {ULTRASONICS SONOCHEMISTRY},
year = {2013},
volume = {20},
number = {3},
pages = {978--983},
doi = {{10.1016/j.ultsonch.2012.10.013}}
}
|
| Cengiz U, Gengec NA and Erbil HY (2013), "Surface characterization of flat and rough films of perfluoromethacrylate-methylmethacrylate statistical copolymers synthesized in CO2-expanded monomers", Colloid and Polymer Science., March, 2013. Vol. 291(3), pp. 641-652. |
| Abstract: Statistical copolymers of perfluoroalkyl ethyl methacrylate (Zonyl-TM) and methylmethacrylate were synthesized in CO2-expanded monomer mixture at a low pressure of 10-13 MPa for the first time. M (w) of the copolymers was found to decrease with the increase of Zonyl-TM content. Flat films of these copolymers were obtained by dip coating from their chloroform solutions and were characterized using contact angle measurements, optical microscopy, and 3D profilometry. The increase in the Zonyl-TM content of the copolymers resulted in a decrease of the total surface free energy. Superhydrophobic and oleophobic rough copolymer films were also prepared by applying a phase-separation process where THF was used as the solvent and ethanol as the non-solvent. Surface roughness increased with the increase in the nonsolvent ratio resulting in an increase in the water contact angle from 103A degrees to 151A degrees and hexadecane contact angle from 49A degrees to 73A degrees. |
BibTeX:
@article{Cengiz2013,
author = {Cengiz, U. and Gengec, N. A. and Erbil, H. Y.},
title = {Surface characterization of flat and rough films of perfluoromethacrylate-methylmethacrylate statistical copolymers synthesized in CO2-expanded monomers},
journal = {Colloid and Polymer Science},
year = {2013},
volume = {291},
number = {3},
pages = {641--652},
doi = {10.1007/s00396-012-2766-z}
}
|
| Kuram E, Ozcelik B, Bayramoglu M, Demirbas E and Simsek BT (2013), "Optimization of cutting fluids and cutting parameters during end milling by using D-optimal design of experiments", Journal of Cleaner Production., March, 2013. Vol. 42, pp. 159-166. |
| Abstract: The use of synthetic cutting fluids is nowadays limited due to the adverse effects such as health of the operator, environmental and economic reasons. In order to diminish these negative effects, bio-based cutting fluids are used. Bio-based or vegetable based cutting fluid is considered environmentally friendly and sustainable. Vegetable based cutting fluids have some characteristics such as biodegradability, less toxicity and renewability. This study deals with the assessment of vegetable based cutting fluids for end milling. For this purpose, effects of cutting fluid types are investigated as a function of three milling factors (cutting speed, depth of cut and feed rate) on process responses (specific energy, tool life and surface roughness). D-optimal method is conducted to develop mathematical models for process responses. Variance analysis shows that specific energy, surface roughness and tool life can be predicted effectively with quadratic models. Furthermore, mono and multi objective optimization studies are conducted using specific energy, surface roughness and tool life as primary or secondary objectives. From results of the optimization, various conclusions are drawn about effects of the milling parameters and the cutting fluid types on the milling performance criteria. The most appropriate cutting fluid during milling of AISI 304 material is selected in accordance with energy, tool life and surface roughness. (C) 2012 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Kuram2013,
author = {Kuram, E. and Ozcelik, B. and Bayramoglu, M. and Demirbas, E. and Simsek, B. T.},
title = {Optimization of cutting fluids and cutting parameters during end milling by using D-optimal design of experiments},
journal = {Journal of Cleaner Production},
year = {2013},
volume = {42},
pages = {159--166},
doi = {10.1016/j.jclepro.2012.11.003}
}
|
| Erbil HY (2013), "Bioadhesion to solids: contact angle hysteresis effect", Colloid and Polymer Science., February, 2013. Vol. 291(2), pp. 355-360. |
| Abstract: It was recently reported that the ease of removal of sporelings of green seaweed Ulva under shear stress from the polymer surfaces was found to be linearly and positively correlated with contact angle and wetting hysteresis, i.e., the higher the hysteresis, the greater the removal. Motivated by this report, we examined the relationship between the bioadhesion of blood platelets and proteins with contact angle hysteresis of solid substrates using the data of published papers. It was determined that there is a linear and positive relationship between the contact angle hysteresis and bioadhesion of both blood platelets and gamma-globulin protein contacting the solid substrates, i.e., the higher the hysteresis, the greater the bioadhesion. The reasons are discussed and it is proposed that testing the effect of CAH on the adhesion strengths of biomaterials on surfaces is useful in order to gain a better insight on the bioadhesion mechanism. |
BibTeX:
@article{Erbil2013,
author = {Erbil, H. Y.},
title = {Bioadhesion to solids: contact angle hysteresis effect},
journal = {Colloid and Polymer Science},
year = {2013},
volume = {291},
number = {2},
pages = {355--360},
doi = {10.1007/s00396-012-2819-3}
}
|
| Ergan BT and Bayramoglu M (2013), "The effects of microwave power and dielectric properties on the microwave-assisted decomposition kinetics of AIBN in n-butanol", Journal of Industrial and Engineering Chemistry., January, 2013. Vol. 19(1), pp. 299-304. |
| Abstract: The effects of microwave power and solvent-reactant dielectric properties on the kinetics of the decomposition of AIBN in n-butanol were investigated. According to the kinetic data, k increases with increasing microwave power, the dependence becomes stronger at high temperature. The Arrhenius parameters (E-a,E-mw, k(o,mw)) were higher than thermal counterparts. To elucidate the nature of microwave effect on chemical reactions, various models to relate the Arrhenius parameters to temperature, microwave power and the dielectric properties of the reaction medium were developed, nonlinear regression analysis was performed to estimate the model parameters and statistical analysis was conducted for model evaluation. (C) 2012 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved. |
BibTeX:
@article{Ergan2013,
author = {Ergan, B. T. and Bayramoglu, M.},
title = {The effects of microwave power and dielectric properties on the microwave-assisted decomposition kinetics of AIBN in n-butanol},
journal = {Journal of Industrial and Engineering Chemistry},
year = {2013},
volume = {19},
number = {1},
pages = {299--304},
doi = {10.1016/j.jiec.2012.08.015}
}
|
| Tercan S and Seker M (2012), "Comparison of polyphenol extractions from olive pomace and solid fraction of olive mill waste water", Natural Product Research. Vol. 26(19), pp. 1837-1841. |
| Abstract: The solid fraction of olive mill waste water (OMWW) was separated from OMWW and then the solutes in the solid fraction of OMWW were extracted with ethanol. The detection of polyphenols in the ethanol extract showed the presence of polyphenols in the solid fraction of OMWW. Effects of solvent-to-solid ratio, extraction and agitation time on the extraction of polyphenols from the solid fraction of OMWW were examined and the maximum amount of polyphenol was extracted from the solid fraction of OMWW with a solvent-to-solid ratio of 15 at 70 min of extraction and 10 min of agitation time. Percent yields and purities of the polyphenols extracted from solid fraction of OMWW were higher than those of the polyphenols extracted from olive pomace with ethanol at 70 min of extraction and 10 min of agitation time with solvent-to-solid ratio of 15. |
BibTeX:
@article{Tercan2012,
author = {Tercan, S. and Seker, M.},
title = {Comparison of polyphenol extractions from olive pomace and solid fraction of olive mill waste water},
journal = {Natural Product Research},
year = {2012},
volume = {26},
number = {19},
pages = {1837--1841},
doi = {10.1080/14786419.2011.582840}
}
|
| Ucar IO and Erbil HY (2012), "Use of diffusion controlled drop evaporation equations for dropwise condensation during dew formation and effect of neighboring droplets", Colloids and Surfaces A-physicochemical and Engineering Aspects., October, 2012. Vol. 411, pp. 60-68. |
| Abstract: In this study, we determined that the equations derived for the diffusion controlled drop evaporation processes can be successfully applied to the condensation rate of water droplets on polymer surfaces having a surface temperature just below the dew point. The differences between the growth rates of condensed isolated droplets on five different polyolefin surfaces, whose surface free energies were in a close range of 30-37 mJ/m(2), were attributed to the difference in surface roughness which alters the droplet nucleation rate, drop pinning effect and initial contact angles. The condensation rate of isolated droplets decreased with the increase of surface roughness, water contact angle and contact angle hysteresis in the order of ethylene-vinyl acetate copolymer (EVA)> low density polyethylene (LDPE)> high density polyethylene (HDPE) > polypropylene-polyethylene copolymer (PPPE) > polypropylene (PP). The drop radius of the individual isolated droplets was found to grow according a power law with exponent 1/3 except PP similar to previous reports. We also compared the volume increase of an isolated single droplet with the volume increase of another similar sized single droplet which was surrounded by neighboring droplets and found that when neighboring droplets are present in close proximity, the condensation rate was 14-40% lower than that of a single isolated droplet due to blocking of lateral water vapor diffusion. This effect was more pronounced on substrates having high surface roughness. (C) 2012 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Ucar2012a,
author = {Ucar, I. O. and Erbil, H. Y.},
title = {Use of diffusion controlled drop evaporation equations for dropwise condensation during dew formation and effect of neighboring droplets},
journal = {Colloids and Surfaces A-physicochemical and Engineering Aspects},
year = {2012},
volume = {411},
pages = {60--68},
doi = {10.1016/j.colsurfa.2012.07.002}
}
|
| Ucar IO and Erbil HY (2012), "Dropwise condensation rate of water breath figures on polymer surfaces having similar surface free energies", Applied Surface Science., October, 2012. Vol. 259, pp. 515-523. |
| Abstract: This study investigates the effect of surface roughness, wettability, water contact angle hysteresis (CAH) and wetting hysteresis (WH) of polymeric substrates to the water drop condensation rate. We used five polyolefin coatings whose surface free energies were in a close range of 30-37 mJ/m(2) but having different surface roughness and CAH. The formation of water breath figures was monitored at a temperature just below the dew point. The initial number of the condensed droplets per unit area (N-0) and droplet surface coverage were determined during the early stage of drop condensation where the droplet coalescence was negligible. It was found that the mean drop diameter of condensed droplets on these polymer surfaces grow according to a power law with exponent 1/3 of time, similar to the previous reports given in the literature. It was determined that surface roughness and corresponding CAH and WH properties of polymers have important effects on the number of nucleation sites and growth rate of the condensed water droplets. N-0 values and the surface coverage increased with the increase in surface roughness, CAH and WH of the polymer surfaces. The total condensed water drop volume also increased with the increase in surface roughness in accordance with the increase of the number of nucleated droplets. (C) 2012 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Ucar2012,
author = {Ucar, I. O. and Erbil, H. Y.},
title = {Dropwise condensation rate of water breath figures on polymer surfaces having similar surface free energies},
journal = {Applied Surface Science},
year = {2012},
volume = {259},
pages = {515--523},
doi = {10.1016/j.apsusc.2012.07.076}
}
|
| Aras O and Bayramoglu M (2012), "A MINLP Study on Shell and Tube Heat Exchanger: Hybrid Branch and Bound/Meta-heuristics Approaches", Industrial & Engineering Chemistry Research., October, 2012. Vol. 51(43), pp. 14158-14170. |
| Abstract: Optimal design of shell and tube heat exchangers (STHE) has a crucial role in terms of the energy efficiency of plants. Therefore, it is currently one of the research topics of interest. In this study, a rigorous STHE design model strictly following TEMA standards and including various crucial constraints was established. Ten design variables of various kinds (continuous, integer, discrete, binary, and type) were selected for MINLP task. The handling of noncontinuous variables was attempted by means of three approaches including GA, PSO, and hybrid branch and bound methods over three case studies. Comparisons of the algorithms were performed using various performance Criteria. Besides, the presence of noncontinuous variables in MINLP was analyzed. As a brief result, when type/binary/integer variables were included as optimization variables, very poor results were obtained, and hybrid PSO exhibited performance in each case superior to the others in terms of objective function value. |
BibTeX:
@article{Aras2012,
author = {Aras, O. and Bayramoglu, M.},
title = {A MINLP Study on Shell and Tube Heat Exchanger: Hybrid Branch and Bound/Meta-heuristics Approaches},
journal = {Industrial & Engineering Chemistry Research},
year = {2012},
volume = {51},
number = {43},
pages = {14158--14170},
doi = {10.1021/ie3011462}
}
|
| Tarlak F, Sadikoglu H and Cakir T (2012), "Role of Flexibility and Minimal Enzyme Production in the Prediction of Intracellular Fluxes of Microorganisms", New Biotechnology., September, 2012. Vol. 29, pp. S146-S146. |
BibTeX:
@article{Tarlak2012,
author = {Tarlak, F. and Sadikoglu, H. and Cakir, T.},
title = {Role of Flexibility and Minimal Enzyme Production in the Prediction of Intracellular Fluxes of Microorganisms},
journal = {New Biotechnology},
year = {2012},
volume = {29},
pages = {S146--S146},
doi = {10.1016/j.nbt.2012.08.405}
}
|
| Oksuz M, Sadikoglu H and Cakir T (2012), "Network Inference via Computational Analysis of Metabolome Data", New Biotechnology., September, 2012. Vol. 29, pp. S148-S148. |
BibTeX:
@article{Oksuz2012,
author = {Oksuz, M. and Sadikoglu, H. and Cakir, T.},
title = {Network Inference via Computational Analysis of Metabolome Data},
journal = {New Biotechnology},
year = {2012},
volume = {29},
pages = {S148--S148},
doi = {10.1016/j.nbt.2012.08.411}
}
|
| Cengiz U, Avci MZ, Erbil HY and Sarac AS (2012), "Superhydrophobic terpolymer nanofibers containing perfluoroethyl alkyl methacrylate by electrospinning", Applied Surface Science., May, 2012. Vol. 258(15), pp. 5815-5821. |
| Abstract: A new statistical terpolymer containing perfluoroethyl alkyl methacrylate (Zonyl-TM), methyl methacrylate and butyl acrylate, poly(Zonyl-TM-ran-MMA-ran-BA) was synthesized in supercritical carbon dioxide at 200 bar and 80 degrees C using AIBN as an initiator by heterogeneous free radical copolymerization. Nanofibers of this terpolymer were produced by electrospinning from its DMF solution. The structural and thermal properties of terpolymers and electrospun poly(Zonyl-TM-MMA-BA) nanofibers were analyzed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and differential scanning calorimetry. Nanofiber morphology was investigated by scanning electron microscopy. Electrospun nanofiber layer was found to be superhydrophobic with a water contact angle of 172 +/- 1 degrees and highly oleophobic with hexadecane, glycerol and ethylene glycol contact angles of 70 perpendicular to 1 degrees, 167 perpendicular to 1 degrees and 163 perpendicular to 1 degrees respectively. The change of the contact angle results on the electrospun fiber layer and flat terpolymer surfaces by varying feed monomer composition were compared and discussed in the text. (C) 2012 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Cengiz2012,
author = {Cengiz, U. and Avci, M. Z. and Erbil, H. Y. and Sarac, A. S.},
title = {Superhydrophobic terpolymer nanofibers containing perfluoroethyl alkyl methacrylate by electrospinning},
journal = {Applied Surface Science},
year = {2012},
volume = {258},
number = {15},
pages = {5815--5821},
doi = {10.1016/j.apsusc.2012.02.107}
}
|
| Doganci MD, Cansoy CE, Ucar IO, Erbil HY, Mielczarski E and Mielczarski JA (2012), "Combined XPS and contact angle studies of flat and rough ethylene-vinyl acetate copolymer films", Journal of Applied Polymer Science., May, 2012. Vol. 124(3), pp. 2100-2109. |
| Abstract: Flat and rough thin films were prepared by dip coating using LDPE, PVAc, and EVA polymers containing 1240% VA contents. Surface free energy of flat films was determined by measuring contact angles. Surface atomic composition was investigated by XPS at 0 degrees and 60 degrees take-off angles. XPS results show that hydrophobic PE component was found to enrich at the near-surface region for all EVA samples for a depth of similar to 5 nm for both flat and rough surfaces, whereas hydrophilic VA component was enriched on the surface when VA < 18% for only at 10 nm depth. The difference between the XPS results of the flat and rough surfaces was not significant for EVA samples except EVA-33 surface where the atomic oxygen content decreased 15-20% for rough surfaces. Contact angle hysteresis values for the rough samples were much larger than that of the flat samples for LDPE and EVA-12 surfaces due to the presence of partial trapping of air pockets on these rough surfaces. A good agreement was obtained between surface concentration of atomic oxygen in the 5 nm outermost layer and gamma S- surface free energy component especially for the samples having high VA contents. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 |
BibTeX:
@article{Doganci2012,
author = {Doganci, M. D. and Cansoy, C. E. and Ucar, I. O. and Erbil, H. Y. and Mielczarski, E. and Mielczarski, J. A.},
title = {Combined XPS and contact angle studies of flat and rough ethylene-vinyl acetate copolymer films},
journal = {Journal of Applied Polymer Science},
year = {2012},
volume = {124},
number = {3},
pages = {2100--2109},
doi = {10.1002/app.35189}
}
|
| Seker M and Tercan S (2012), "Kinetics of Polyphenol Losses and Antioxidant Activity of Extracts from Olive Cake during Evaporation", International Journal of Food Properties., January, 2012. Vol. 15(1-2), pp. 438-449. |
| Abstract: Polyphenols were extracted from olive cake and then concentrated at 50, 75, and 100 degrees C by the evaporation of extract. Antioxidant activity of total polyphenols in olive cake extract decreased while the concentration of total polyphenols increased during the evaporation of extract at 100 degrees C, but concentration of polyphenols slightly increased while antioxidant activity did not change at 75 degrees C. These results showed that antioxidant activity is not related and estimated with the amount of total polyphenols. Reaction rate for the loss of polyphenols is found zero order at 50 and 75 degrees C with r(2) of 0.99 and at 100 degrees C with r(2) of 0.85. Low r(2) value at 100 degrees C requires the consideration of a different kinetic model to predict the losses of polyhenols at a high temperature of 100 degrees C. |
BibTeX:
@article{Seker2012,
author = {Seker, M. and Tercan, S.},
title = {Kinetics of Polyphenol Losses and Antioxidant Activity of Extracts from Olive Cake during Evaporation},
journal = {International Journal of Food Properties},
year = {2012},
volume = {15},
number = {1-2},
pages = {438--449},
doi = {10.1080/10942912.2010.487968}
}
|
| Erbil HY (2012), "Evaporation of pure liquid sessile and spherical suspended drops: A review", Advances in Colloid and Interface Science., January, 2012. Vol. 170(1-2), pp. 67-86. |
| Abstract: A sessile drop is an isolated drop which has been deposited on a solid substrate where the wetted area is limited by a contact line and characterized by contact angle, contact radius and drop height. Diffusion-controlled evaporation of a sessile drop in an ambient gas is an important topic of interest because it plays a crucial role in many scientific applications such as controlling the deposition of particles on solid surfaces, in ink-jet printing, spraying of pesticides, micro/nano material fabrication. thin film coatings, biochemical assays, drop wise cooling, deposition of DNA/RNA micro-arrays, and manufacture of novel optical and electronic materials in the last decades. This paper presents a review of the published articles for a period of approximately 120 years related to the evaporation of both sessile drops and nearly spherical droplets suspended from thin fibers. After presenting a brief history of the subject, we discuss the basic theory comprising evaporation of micrometer and millimeter sized spherical drops, self cooling on the drop surface and evaporation rate of sessile drops on solids. The effects of drop cooling, resultant lateral evaporative flux and Marangoni flows on evaporation rate are also discussed. This review also has some special topics such as drop evaporation on superhydrophobic surfaces, determination of the receding contact angle from drop evaporation, substrate thermal conductivity effect on drop evaporation and the rate evaporation of water in liquid marbles. (C) 2012 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Erbil2012,
author = {Erbil, H. Y.},
title = {Evaporation of pure liquid sessile and spherical suspended drops: A review},
journal = {Advances in Colloid and Interface Science},
year = {2012},
volume = {170},
number = {1-2},
pages = {67--86},
doi = {10.1016/j.cis.2011.12.006}
}
|
| Acar B, Sadikoglu H and Ozkaymak M (2011), "Freeze Drying of Saffron (Crocus sativus L.)", Drying Technology. Vol. 29(14), pp. 1622-1627. |
| Abstract: Saffron obtained from the dried stigmas of a flower scientifically known as Crocus sativus L. is considered to be the most precious and expensive agricultural product due to its labor-intensive harvest and post-harvest processing. The post-harvest processing such as dehydration and storage conditions determine stability, quality, and economical value of the final product. The contents of crocin (degraded carotenoids) and safranal (carotenoid oxidation products) are the key components that characterize color, taste, and aroma characteristics of saffron. In this work, the quality parameters such as crocin and safranal contents of commercial saffron that were obtained by using the freeze-drying method and natural sun drying were studied. The sarfanal contents of the samples dried in a freeze dryer were found to be five times higher than the safranal contents of the samples dried naturally under the sun, while crocin contents of the samples dried in a freeze dryer were about 40% higher than the crocin contents of the samples dried naturally under the sun. These encouraging results indicate that the freeze-drying process can be used effectively for dehydration of saffron by minimal loss of safranal and crocin contents. |
BibTeX:
@article{Acar2011,
author = {Acar, B. and Sadikoglu, H. and Ozkaymak, M.},
title = {Freeze Drying of Saffron (Crocus sativus L.)},
journal = {Drying Technology},
year = {2011},
volume = {29},
number = {14},
pages = {1622--1627},
doi = {10.1080/07373937.2011.590263}
}
|
| Erbil HY (2011), "Bacterial Adhesion to Low Energy Solid Surfaces: A Surface Thermodynamics Approach", Journal of Adhesion Science and Technology. Vol. 25(17), pp. 2137-2153. |
| Abstract: A desired approach to reduce bacterial adhesion to ship hull, heat exchanger and medical device surfaces is to make them less attractive for bacteria by applying anti-fouling or foul-release surface coatings. However, the selection of a useful anti-fouling coating is a difficult problem and surface thermodynamics may guide us in this respect. In this work, we investigated the independent contributions of substrate-water, gamma(Tot)(SW), substrate-bacteria, gamma(Tot)(SB), and bacteria-water, gamma(Tot)(BW), interfacial free energies to the total free energy of adhesion, Delta G(SWB)(Tot), of Pseudomonas fluorescens bacteria on the Si-and SiN-doped DLC coated glass slide surfaces using the Lifshitz-van der Waals and acid-base surface free energy components theory. It was found that mostly acid-base interactions determine the bacterial removal properties. The repulsion between bacteria and the solid surface in water increases if gamma(AB)(SB) is large and gamma(AB)(SW) is small, when they are both positive. When Lifshitz-van der Waals and acid-base components of free energy of adhesion are considered, it was found that the effect of Delta G(SWB)(LW) was very small and the main effect on bacterial removal was found to depend on the Delta G(SWB)(AB) parameter and bacterial % removal increased linearly with the increase of both Delta G(SWB)(AB) and Delta G(SWB)(Tot) parameters for all the samples. (C) Koninklijke Brill NV, Leiden, 2011 |
BibTeX:
@article{Erbil2011,
author = {Erbil, H. Y.},
title = {Bacterial Adhesion to Low Energy Solid Surfaces: A Surface Thermodynamics Approach},
journal = {Journal of Adhesion Science and Technology},
year = {2011},
volume = {25},
number = {17},
pages = {2137--2153},
doi = {10.1163/016942411X574871}
}
|
| Meral K, Erbil HY and Onganer Y (2011), "A spectroscopic study of water-soluble pyronin B and pyronin Y in Langmuir-Blodgett films mixed with stearic acid", Applied Surface Science., December, 2011. Vol. 258(4), pp. 1605-1612. |
| Abstract: Mono and multilayer of water-soluble pyronin B (PyB) and pyronin Y (PyY) mixed with stearic acid (SA) have been incorporated in Langmuir-Blodgett (LB) films. The surface pressure-area (pi-A) isotherm studies pointed out that pure PyB and PyY are incapable of forming stable films at air-water interface and collapsed readily at low surface pressures. However, mixture of PyB or PyY with SA easily formed stable films at the air-water interface and they were easily transferred onto solid substrates. The average area per molecule of mixed films of PyB and PyY at the air-water interface was observed to decrease with increasing concentrations of PyB and PyY. The spectroscopic characteristics of PyB and PyY in chloroform, in SA containing chloroform and in LB films have also been investigated by using absorption and steady-state and time-resolved fluorescence spectroscopy techniques. The morphology of the LB film surfaces has been characterized by using atomic force microscopy (AFM). (C) 2011 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Meral2011,
author = {Meral, K. and Erbil, H. Y. and Onganer, Y.},
title = {A spectroscopic study of water-soluble pyronin B and pyronin Y in Langmuir-Blodgett films mixed with stearic acid},
journal = {Applied Surface Science},
year = {2011},
volume = {258},
number = {4},
pages = {1605--1612},
doi = {10.1016/j.apsusc.2011.10.008}
}
|
| Doganci MD, Sesli BU and Erbil HY (2011), "Diffusion-controlled evaporation of sodium dodecyl sulfate solution drops placed on a hydrophobic substrate", Journal of Colloid and Interface Science., October, 2011. Vol. 362(2), pp. 524-531. |
| Abstract: In this work, the effect of SDS anionic surfactant on the diffusion-controlled evaporation rate of aqueous solution drops placed on TEFLON-FEP substrate was investigated with 11 different SDS concentrations. Drop evaporation was monitored in a closed chamber having a constant RH of 54-57% by a video camera. The initial contact angle, theta(i) decreased from 104 +/- 2 degrees down to 68 +/- 1 degrees due to the adsorption of SDS both at the water-air and the solid-water interfaces. The adsorption of SDS on the solid surface was found to be 76% of that of its adsorption at the water-air interface by applying Lucassen-Reynders approach. An equation was developed for the comparison of the evaporation rates of drops having different theta(i) on the same substrate. It was found that the addition of SDS did not alter the drop evaporation rate considerably for the first 1200 s for all the SDS concentrations. The main difference was found to be the change of the mode of drop evaporation by varying the SDS concentration. The constant theta mode was operative up to 80 mM SDS concentration, whereas constant contact area mode was operative after 200 mM SDS concentrations due to rapid drop pining on the substrate. (C) 2011 Elsevier Inc. All rights reserved. |
BibTeX:
@article{Doganci2011,
author = {Doganci, M. D. and Sesli, B. U. and Erbil, H. Y.},
title = {Diffusion-controlled evaporation of sodium dodecyl sulfate solution drops placed on a hydrophobic substrate},
journal = {Journal of Colloid and Interface Science},
year = {2011},
volume = {362},
number = {2},
pages = {524--531},
doi = {10.1016/j.jcis.2011.06.060}
}
|
| Ucar IO, Doganci MD, Cansoy CE, Erbil HY, Avramova I and Suzer S (2011), "Combined XPS and contact angle studies of ethylene vinyl acetate and polyvinyl acetate blends", Applied Surface Science., September, 2011. Vol. 257(22), pp. 9587-9594. |
| Abstract: In this study, we prepared thin films by blending ethylene vinyl acetate copolymers (EVA) containing 12-33 (wt.%) vinyl acetate (VA) with polyvinyl acetate (PVAc) and high density polyethylene homopolymers. Large area micropatterns having controlled protrusion sizes were obtained by phase-separation especially for the PVAc/EVA-33 blends using dip coating. These surfaces were characterized by XPS and contact angle measurements. A reasonably linear relation was found between the VA content on the surface (wt.%) obtained from XPS analysis and the VA content in bulk especially for PVAc/EVA-33 blend surfaces. PE segments were more enriched on the surface than that of the bulk for pure EVA copolymer surfaces similar to previous reports and VA enrichment was found on the EVA/HDPE blend surfaces due to high molecular weight of HDPE. Water theta(e) decreased with the increase in the VA content on the blend surface due to the polarity of VA. A good agreement was obtained between gamma(-)(s) and atomic oxygen surface concentration with the increase of VA content. The applicability of Cassie-Baxter equation was tested and found that it gave consistent results with the experimental water contact angles for the case where VA content was lower than 55 wt.% in the bulk composition. (C) 2011 Elsevier B. V. All rights reserved. |
BibTeX:
@article{Ucar2011,
author = {Ucar, I. O. and Doganci, M. D. and Cansoy, C. E. and Erbil, H. Y. and Avramova, I. and Suzer, S.},
title = {Combined XPS and contact angle studies of ethylene vinyl acetate and polyvinyl acetate blends},
journal = {Applied Surface Science},
year = {2011},
volume = {257},
number = {22},
pages = {9587--9594},
doi = {10.1016/j.apsusc.2011.06.070}
}
|
| Cansoy CE, Erbil HY, Akar O and Akin T (2011), "Effect of pattern size and geometry on the use of Cassie-Baxter equation for superhydrophobic surfaces", Colloids and Surfaces A-physicochemical and Engineering Aspects., August, 2011. Vol. 386(1-3), pp. 116-124. |
| Abstract: Cassie-Baxter equation depending on the extent of liquid/solid interfacial contact area was generally used in the past to estimate water contact angles on superhydrophobic surfaces. However, there are objections refuting the contact area based equations and suggesting that the three-phase contact line determines the apparent contact angle. In this study, we tested the validity of Cassie-Baxter equation on superhydrophobic surfaces. 36 pattern samples made of square and 24 of cylindrical pillars were prepared by applying the DRIE technique on Si-wafers. Pillar side lengths and diameters were varied between 8 and 100 mu m and the height of pillars was kept nearly constant between 30 and 34 mu m. 18 square and 12 cylindrical patterns were coated by hydrophobic dimethyldichlorosilane vapor to obtain superhydrophobic surfaces. Recent method of Erbil and Cansoy was used to test the validity of Cassie-Baxter equation to estimate the water contact angles on these superhydrophobic surfaces. It was found that Cassie-Baxter equation was valid only for some special pattern geometry. The factors affecting the applicability of the Cassie-Baxter equation such as geometric type of the pillars, size of pillars and separation distance between the pillars are discussed throughout the text. (C) 2011 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Cansoy2011,
author = {Cansoy, C. E. and Erbil, H. Y. and Akar, O. and Akin, T.},
title = {Effect of pattern size and geometry on the use of Cassie-Baxter equation for superhydrophobic surfaces},
journal = {Colloids and Surfaces A-physicochemical and Engineering Aspects},
year = {2011},
volume = {386},
number = {1-3},
pages = {116--124},
doi = {10.1016/j.colsurfa.2011.07.005}
}
|
| Doganci MD, Sesli BU, Erbil HY, Binks BP and Salama IE (2011), "Liquid marbles stabilized by graphite particles from aqueous surfactant solutions", Colloids and Surfaces A-physicochemical and Engineering Aspects., July, 2011. Vol. 384(1-3), pp. 417-426. |
| Abstract: When a hydrophobic powder encapsulates a liquid drop, it forms a liquid marble which is non-wetting and behaves as a micro-reservoir of the liquid able to move without any leakage. In this work, we successfully prepared liquid marbles by encapsulating graphite micropowder on aqueous sodium dodecyl sulfate (SDS) droplets and determined their total evaporation and buckling periods in a closed chamber having constant relative humidity and temperature. The evaporation rates of graphite liquid marbles obtained from SDS solutions were compared with the rates of graphite liquid marbles from pure water and also with aqueous SOS droplets in the same conditions. The effects of SDS adsorption at the graphite-water and air-water interfaces on the formation and evaporation behavior of graphite liquid marbles are discussed. (C) 2011 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Doganci2011a,
author = {Doganci, M. D. and Sesli, B. U. and Erbil, H. Y. and Binks, B. P. and Salama, I. E.},
title = {Liquid marbles stabilized by graphite particles from aqueous surfactant solutions},
journal = {Colloids and Surfaces A-physicochemical and Engineering Aspects},
year = {2011},
volume = {384},
number = {1-3},
pages = {417--426},
doi = {10.1016/j.colsurfa.2011.04.027}
}
|
| Ergan BT and Bayramoglu M (2011), "Kinetic Approach for Investigating the "Microwave Effect": Decomposition of Aqueous Potassium Persulfate", Industrial & Engineering Chemistry Research., June, 2011. Vol. 50(11), pp. 6629-6637. |
| Abstract: In this work, the specific effect of microwave (MW) energy on chemical reactions was investigated by online monitoring of the decomposition kinetics of potassium persulfate (K2S2O8). Experiments conducted at constant temperature and constant MW power revealed that the rate constant was about 1.1-1.8 times higher than the rate constant of the thermally heated system at the same temperature, depending on the MW power. To model the dependence of the rate constant on the MW power as k = f(P) exp(-g(P)/T), various functional forms of MW power were envisaged for g(P) (activation energy E-a) and for f(P) (preexponential factor k(o)). Linear, quadratic, and cubic polynomial models were tried for both functions. Nonlinear regression analysis was performed and detailed statistical analysis was applied, and the best results were obtained with quadratic f(P) and cubic g(P) functions, with the highest R-adj(2) (0.9975) and the lowest standard deviation (0.94 x 10(-5)). The mathematical model revealed that both the activation energy and preexponential factor were higher than their thermal counterparts (for P = 0.75 kW dm(-3), k(o,mw)/k(o,th) = 120, E-a,E-mw/E-a,E-th = 1.12). |
BibTeX:
@article{Ergan2011,
author = {Ergan, B. T. and Bayramoglu, M.},
title = {Kinetic Approach for Investigating the "Microwave Effect": Decomposition of Aqueous Potassium Persulfate},
journal = {Industrial & Engineering Chemistry Research},
year = {2011},
volume = {50},
number = {11},
pages = {6629--6637},
doi = {10.1021/ie200095y}
}
|
| Cengiz U, Gengec NA, Kaya NU, Erbil HY and Sarac AS (2011), "Mechanical and thermal properties of perfluoroalkyl ethyl methacrylate-methyl methacrylate statistical copolymers synthesized in supercritical carbon dioxide", Journal of Fluorine Chemistry., May, 2011. Vol. 132(5), pp. 348-355. |
| Abstract: Poly( methyl methacrylate-ran-perfluoroalkyl ethyl methacrylate) copolymers having varying perfluoralkyl ethyl methacrylate ester (Zonyl-TM) contents were synthesized in supercritical CO(2). Complete amorphous structures of the copolymers were verified by XRD. Young's modulus (Y(mod)) of the copolymers was decreased linearly from 1.57 to 1.08 GPa and T(g) values from 102 to 77 C with the increase of Zonyl-TM content. A linear relationship between the Y(mod) and the T, values of the copolymer was also found. The increase of the large branched pendant groups resulted in the increase of the free volume and a corresponding decrease in Ymod and T(g) of the copolymers. A good fit was found when the Schneider equation was used. Negative deviation from the Gordon-Taylor equation was observed when Zonyl-TM content was lower than 14% due to rapid increase in free volume and then a positive deviation was found due to the dipole-dipole interactions between the methyl ester and fluoroalkyl ester groups. (C) 2011 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Cengiz2011,
author = {Cengiz, U. and Gengec, N. A. and Kaya, N. U. and Erbil, H. Y. and Sarac, A. S.},
title = {Mechanical and thermal properties of perfluoroalkyl ethyl methacrylate-methyl methacrylate statistical copolymers synthesized in supercritical carbon dioxide},
journal = {Journal of Fluorine Chemistry},
year = {2011},
volume = {132},
number = {5},
pages = {348--355},
doi = {10.1016/j.jfluchem.2011.03.010}
}
|
| Aras O, Bayramoglu M and Hasiloglu AS (2011), "Optimization of Scaled Parameters and Setting Minimum Rule Base for a Fuzzy Controller in a Lab-Scale pH Process", Industrial & Engineering Chemistry Research., March, 2011. Vol. 50(6), pp. 3335-3344. |
| Abstract: Experimental and simulation studies were conducted to design a multiregional fuzzy logic controller (FLC) for a lab-scale pH process system. Scaled coefficients of the controller were optimized offline to obtain the best controller performance in terms of cost function and function evaluation number using two widely used global optimization methods; namely, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). Various tuning parameters of these optimization algorithms were investigated in detail to compare their performance on this subject. The cost functions obtained via two algorithms were very close to each other, but the function evaluation number was almost 4-fold due to complicated computation of the GA compared to the PSO. On the other side, working with the PSO was much easier owing to fewer adjustable parameters. In the second part of the study, the rule base of the controller was minimized using two different new methods. In this context, the number of rules was reduced by 43% and 56% using the fuzzy matching set and the personal initiative methods, respectively. Rule base reduction increased the performance and the effectiveness of the controller, an important issue for real-time applications. |
BibTeX:
@article{Aras2011,
author = {Aras, O. and Bayramoglu, M. and Hasiloglu, A. S.},
title = {Optimization of Scaled Parameters and Setting Minimum Rule Base for a Fuzzy Controller in a Lab-Scale pH Process},
journal = {Industrial & Engineering Chemistry Research},
year = {2011},
volume = {50},
number = {6},
pages = {3335--3344},
doi = {10.1021/ie2001023}
}
|
| Kobya M, Demirbas E, Bayramoglu M and Sensoy MT (2011), "Optimization of Electrocoagulation Process for the Treatment of Metal Cutting Wastewaters with Response Surface Methodology", Water Air and Soil Pollution., February, 2011. Vol. 215(1-4), pp. 399-410. |
| Abstract: In the present investigation, treatment of metal cutting wastewater (MCW) using electrocoagulation (EC) process is designed and analyzed using response surface methodology (RSM). RSM is applied to optimize the operating variables viz. initial pH, current density, and operating time on the treatment of MCW in a batch mode by EC process using iron and aluminum electrodes. Quadratic models are developed for the responses such as chemical oxygen demand (COD), total organic carbon (TOC), and turbidity, and operating cost is calculated with respect to energy, electrode, and chemical consumptions. The actual COD, TOC, and turbidity removal efficiencies at optimized conditions are found to be 93.0%, 83.0%, and 99.8% for Fe electrode and 93.5%, 85.2%, and 99.9% for Al electrode, respectively, which agree well with the predicted response. The proposed model fits very well with the experimental data with R (2) adjusted correlation coefficients of 0.927 for COD, 0.924 for TOC, and 0.968 for turbidity removal for Al and 0.904 for COD, 0.976 for TOC, and 0.989 for turbidity removal for Fe electrodes, respectively. This study clearly shows that RSM is one of the suitable methods to optimize the operating conditions and maximize the COD, TOC, and turbidity removal efficiencies for both electrodes while keeping the operating costs to minimal (0.371 a,not sign/m(3) for Fe and 0.337 a,not sign/m(3) for Al electrodes). |
BibTeX:
@article{Kobya2011,
author = {Kobya, M. and Demirbas, E. and Bayramoglu, M. and Sensoy, M. T.},
title = {Optimization of Electrocoagulation Process for the Treatment of Metal Cutting Wastewaters with Response Surface Methodology},
journal = {Water Air and Soil Pollution},
year = {2011},
volume = {215},
number = {1-4},
pages = {399--410},
doi = {10.1007/s11270-010-0486-x}
}
|
| Arslan-Alaton I, Gursoy BH, Akyol A, Kobya M and Bayramoglu M (2010), "Modeling and optimization of acid dye manufacturing wastewater treatment with Fenton's reagent: comparison with electrocoagulation treatment results and effects on activated sludge inhibition", Water Science and Technology. Vol. 62(1), pp. 209-216. |
| Abstract: In the present study, Fenton's oxidation of a chromium complex disazo dye (Acid Blue 193) synthesis wastewater was evaluated, modeled and optimized by employing Central Composite Design. Within this context, the individual and interactive effects of critical process parameters such as Fe(2+), H(2)O(2) concentrations, initial chemical oxygen demand (COD) and reaction time was assessed. The process response (output) variables were chosen as percent color, COD and total organic carbon (TOC) removal efficiencies. Optimum working conditions in terms of color and organic carbon removals were established to be Fe(2+) = 3 mM; H(2)O(2) = 25 mM; reaction time 10 min at pH 3 and an initial COD content of 245 mg/L. Under these conditions, 96% color, 82% COD and 51% TOC removals were obtained. The established polynomial regression models describing color, COD and TOC removals satisfactorily fitted the experimental data and could be used to predict Fenton's treatment results at statistically significant rates. Optimized treatment results were compared with those obtained via electrocoagulation treatment under optimized conditions (applied current = 50 A/m(2); reaction time = 15 min; initial pH = 7 for an initial COD content of 245 mg/L). The relative inhibition of heterotrophic oxygen uptake rate was measured to examine the inhibitory effect of azo dye synthesis effluent before and after Fenton's oxidation and electrocoagulation with respect to synthetic domestic wastewater. Untreated azo dye production wastewater exhibited a slightly inhibitory effect that was appreciably reduced but not entirely removed after Fenton's oxidation, whereas no inhibition of mixed bioculture was observed for azo dye synthesis effluent subjected to electrocoagulation treatment. |
BibTeX:
@article{Arslan-Alaton2010,
author = {Arslan-Alaton, I. and Gursoy, B. H. and Akyol, A. and Kobya, M. and Bayramoglu, M.},
title = {Modeling and optimization of acid dye manufacturing wastewater treatment with Fenton's reagent: comparison with electrocoagulation treatment results and effects on activated sludge inhibition},
journal = {Water Science and Technology},
year = {2010},
volume = {62},
number = {1},
pages = {209--216},
doi = {10.2166/wst.2010.256}
}
|
| Akyol A and Bayramoglu M (2010), "Performance comparison of ZnO photocatalyst in various reactor systems", Journal of Chemical Technology and Biotechnology., November, 2010. Vol. 85(11), pp. 1455-1462. |
| Abstract: BACKGROUND: Owing to difficulties in catalyst recovery from slurries the deposition of a catalyst on suitable supports has been investigated extensively in recent years. The support material and the method of coating influence the activity. Photocatalytic decolorization of methyl orange (MO) and Rem Red F3B (RRF3B) was conducted in various reactor systems including a slurry reactor, ZnO thin film coated tube reactor and fixed bed reactor filled with ZnO coated ceramic or glass supports of various geometries. RESULTS: ZnO coating was carried out by the ammonium zincate deposition method. ZnO thin films were quite stable in acidic and basic media and resistant to photocorrosion. Various methods including scanning electron microscopy (SEM) and X-ray diffraction (XRD) were applied for the physical characterization of thin films. The XRD patterns of ZnO thin film exhibit a wurtzite (zincite) crystal structure. SEM analysis revealed the granular morphology of ZnO film with a particle size of 300-400 nm. CONCLUSION: Photocatalytic activities were determined kinetically by calculating first-order rate constants, which were also related to process variables by regression analysis. From the viewpoint of decolorization efficiency, the coated tube reactor (6 mm i.d.) showed the highest activity, which was equal to that of a powder catalyst loading of 300 mg dm(-3) for MO and of 200 mg dm(-3) for RRF3B. (C) 2010 Society of Chemical Industry |
BibTeX:
@article{Akyol2010,
author = {Akyol, A. and Bayramoglu, M.},
title = {Performance comparison of ZnO photocatalyst in various reactor systems},
journal = {Journal of Chemical Technology and Biotechnology},
year = {2010},
volume = {85},
number = {11},
pages = {1455--1462},
doi = {10.1002/jctb.2449}
}
|
| Kibar A, Karabay H, Yigit KS, Ucar IO and Erbil HY (2010), "Experimental investigation of inclined liquid water jet flow onto vertically located superhydrophobic surfaces", Experiments in Fluids., November, 2010. Vol. 49(5), pp. 1135-1145. |
| Abstract: In this study, the behaviour of an inclined water jet, which is impinged onto hydrophobic and superhydrophobic surfaces, has been investigated experimentally. Water jet was impinged with different inclination angles (15A degrees-45A degrees) onto five different hydrophobic surfaces made of rough polymer, which were held vertically. The water contact angles on these surfaces were measured as 102A degrees, 112A degrees, 123A degrees, 145A degrees and 167A degrees showing that the last surface was superhydrophobic. Two different nozzles with 1.75 and 4 mm in diameters were used to create the water jet. Water jet velocity was within the range of 0.5-5 m/s, thus the Weber number varied from 5 to 650 and Reynolds number from 500 to 8,000 during the experiments. Hydrophobic surfaces reflected the liquid jet depending on the surface contact angle, jet inclination angle and the Weber number. The variation of the reflection angle with the Weber number showed a maximum value for a constant jet angle. The maximum value of the reflection angle was nearly equal to half of the jet angle. It was determined that the viscous drag decreases as the contact angle of the hydrophobic surface increases. The drag force on the wall is reduced dramatically with superhydrophobic surfaces. The amount of reduction of the average shear stress on the wall was about 40%, when the contact angle of the surface was increased from 145A degrees to 167A degrees. The area of the spreading water layer decreased as the contact angle of the surface increased and as the jet inclination angle, Weber number and Reynolds number decreased. |
BibTeX:
@article{Kibar2010,
author = {Kibar, A. and Karabay, H. and Yigit, K. S. and Ucar, I. O. and Erbil, H. Y.},
title = {Experimental investigation of inclined liquid water jet flow onto vertically located superhydrophobic surfaces},
journal = {Experiments in Fluids},
year = {2010},
volume = {49},
number = {5},
pages = {1135--1145},
doi = {10.1007/s00348-010-0864-6}
}
|
| Ucar IO, Cansoy CE, Erbil HY, Pettitt ME, Callow ME and Callow JA (2010), "Effect of contact angle hysteresis on the removal of the sporelings of the green alga Ulva from the fouling-release coatings synthesized from polyolefin polymers", Biointerphases., September, 2010. Vol. 5(3), pp. 75-84. |
| Abstract: Wettability is one of the surface characteristics that is controlled by the chemical composition and roughness of a surface. A number of investigations have explored the relationship between water contact angle and surface free energy of polymeric coatings with the settlement (attachment) and adhesion strength of various marine organisms. However, the relationship between the contact angle hysteresis and fouling-release property is generally overlooked. In the present work, coatings were prepared by using commercial hydrophobic homopolymer and copolymer polyolefins, which have nearly the same surface free energy. The effects of contact angle hysteresis, wetting hysteresis, and surface free energy on the fouling-release properties for sporelings of the green alga Ulva from substrates were then examined quantitatively under a defined shear stress in a water channel. The ease of removal of sporelings under shear stress from the polymer surfaces was in the order of PP>HDPE>PPPE>EVA-12 and strongly and positively correlated with contact angle and wetting hysteresis; i.e., the higher the hysteresis, the greater the removal. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3483467] |
BibTeX:
@article{Ucar2010,
author = {Ucar, I. O. and Cansoy, C. E. and Erbil, H. Y. and Pettitt, M. E. and Callow, M. E. and Callow, J. A.},
title = {Effect of contact angle hysteresis on the removal of the sporelings of the green alga Ulva from the fouling-release coatings synthesized from polyolefin polymers},
journal = {Biointerphases},
year = {2010},
volume = {5},
number = {3},
pages = {75--84},
doi = {10.1116/1.3483467}
}
|
| Akyol A and Bayramoglu M (2010), "Photocatalytic performance of ZnO coated tubular reactor", Journal of Hazardous Materials., August, 2010. Vol. 180(1-3), pp. 466-473. |
| Abstract: The recovery of photocatalyst particles constitutes a serious drawback of slurry reactors. Therefore, depositing the catalyst mass on a suitable support without loss of photocatalytic activity is of practical importance. In this study, a chemical deposition method was applied to coat the inner surface of quartz tubes of various diameters with thin ZnO film. The method is economical, energy efficient and easy to apply. ZnO film is mechanically durable and resistant to chemical dissolution. Various physical tests were conducted to characterize the film. ZnO thin film exhibits the crystal wurtzite structure with band gap calculated as 3.24 eV. The film exhibits highly hydrophilic behavior. The average ZnO crystallite size is estimated as 72 nm. SEM analysis shows that the ZnO film has granular morphology with uniform particle size of about 300-400 nm. The film thickness is calculated as 1.41 mu m after 20 coating cycles and the increase of the thickness of the thin film per cycle was approximately 70 nm. Photochemical activity tests were performed by measuring photo decolorization rate of a commercial azo dye (Rem Red F3B) solution in tubular reactor and as well as in slurry reactor for comparative purpose. First order rate constants were correlated to principal process parameters. The results showed that thin ZnO film has high photocatalytic activity comparable to that of ZnO powder. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved. |
BibTeX:
@article{Akyol2010a,
author = {Akyol, A. and Bayramoglu, M.},
title = {Photocatalytic performance of ZnO coated tubular reactor},
journal = {Journal of Hazardous Materials},
year = {2010},
volume = {180},
number = {1-3},
pages = {466--473},
doi = {10.1016/j.jhazmat.2010.04.053}
}
|
| Akyol A and Bayramoglu M (2010), "Preparation and characterization of supported ZnO photocatalyst by zincate method", Journal of Hazardous Materials., March, 2010. Vol. 175(1-3), pp. 484-491. |
| Abstract: Supported ZnO film photocatalysts are prepared on glass and ceramic substrates by zincate method. Prepared ZnO films are seen rather strongly durable. They resist to chemical dissolution in a broad range of pH from 3 to 10. Various physical tests are conducted to measure the relevant characteristics of the films. Band gap of ZnO film is Calculated as 3.24eV. SEM analysis shows that the ZnO film has granular morphology with uniform particle size about 300-400 nm. The film thickness is calculated as 1.41 mu m after twenty coating cycles and the thickness of the thin film per cycle was approximately 70 turn. Photochemical activity tests are performed by measuring photodecolorization rate of methyl orange solution. First order rate constants are correlated to principal process parameters. The results show that ceramic is the preferable supporting material with high activity. According to simulation study, the photocatalytic activity of film coated on ceramic ring of 8 mm diameter is nearly equal to the activity of powder ZnO slurry of 120 mg/dm(3) density. It carried out about decolorization 65% in 3 h. The calculations show that it is possible to prepare ZnO film on ceramic ring with similar activity as powder ZnO. (C) 2009 Elsevier B.V. All Fights reserved. |
BibTeX:
@article{Akyol2010b,
author = {Akyol, A. and Bayramoglu, M.},
title = {Preparation and characterization of supported ZnO photocatalyst by zincate method},
journal = {Journal of Hazardous Materials},
year = {2010},
volume = {175},
number = {1-3},
pages = {484--491},
doi = {10.1016/j.jhazmat.2009.10.031}
}
|
| Cakmakci M, Kinaci C, Bayramoglu M and Yildirim Y (2010), "A modeling approach for iron concentration in sand filtration effluent using adaptive neuro-fuzzy model", Expert Systems with Applications., March, 2010. Vol. 37(2), pp. 1369-1373. |
| Abstract: Effluent iron concentration is an important water quality criterion used for the assessment of the performance of rapid sand filters, in addition to other criteria. This study deals with the prediction of effluent iron concentrations by adaptive neuro-fuzzy (ANFIS) model with input parameters including filter hydraulic loading rate, Influent iron concentration, bed porosity and operation time With trying various types of membership functions. two rule base generation methods, namely subtractive Clustering and grid partition were used for a first order Sugeno type inference system. Models were evaluated using root mean squared error(RMSE), index of agreernent (IA) and R(2) as statistical performance parameters The fit between experimental results and model outputs showed good agreement for tap water and deionized water, testing RMSE values were 36 33 and 7 66 mu g/L. the IA values were 0 996 and 0 971. and R(2) Values were 0.99 and 0 89, respectively. It was concluded that neuro-fuzzy modeling may be successfully used to predict effluent iron concentration in sand filtration (C) 2009 Elsevier Ltd All rights reserved. |
BibTeX:
@article{Cakmakci2010,
author = {Cakmakci, M. and Kinaci, C. and Bayramoglu, M. and Yildirim, Y.},
title = {A modeling approach for iron concentration in sand filtration effluent using adaptive neuro-fuzzy model},
journal = {Expert Systems with Applications},
year = {2010},
volume = {37},
number = {2},
pages = {1369--1373},
doi = {10.1016/j.eswa.2009.06.082}
}
|
| Can OT and Bayramoglu M (2010), "The effect of process conditions on the treatment of benzoquinone solution by electrocoagulation", Journal of Hazardous Materials., January, 2010. Vol. 173(1-3), pp. 731-736. |
| Abstract: The present study provides an electrocoagulation (EC) process for the removal of p-benzoquinone (BQ) from aqueous solution using aluminium as anode and stainless steel as cathode materials. Experiments carried out to investigate the effects of solution pH and conductivity, current density, time, BQ concentration on the removal efficiency of the process and the adsorption capacity of aluminium hydroxide electrocoagulant flocs. The results show that pH 7.5 seems to be optimum for high removal of BQ near 90% at typical operating conditions such as 20 A/m(2) current density and 20 min operating time. The competing reduction of BQ to hydroquinone (HQ) accompanying the H(+) reduction at the cathode and low removal extent of HQ by electrocoagulant flocs decreases the performance of the EC process. (C) 2009 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Can2010,
author = {Can, O. T. and Bayramoglu, M.},
title = {The effect of process conditions on the treatment of benzoquinone solution by electrocoagulation},
journal = {Journal of Hazardous Materials},
year = {2010},
volume = {173},
number = {1-3},
pages = {731--736},
doi = {10.1016/j.jhazmat.2009.08.146}
}
|
| Arslan-Alaton I, Kobya M, Akyol A and Bayramoglu M (2009), "Electrocoagulation of azo dye production wastewater with iron electrodes: process evaluation by multi-response central composite design", Coloration Technology. Vol. 125(4), pp. 234-241. |
| Abstract: Central composite design was used to optimise electrocoagulation of CI Acid Blue 193 production wastewater. By applying a response surface quadratic model, the main process manipulators (effluent chemical oxygen demand, initial pH, electrical current density and treatment time) were optimised to achieve maximum colour, chemical oxygen demand and total organic compound removals. Analysis of variance indicated that the established polynomial regression models were significant and fitted the experimental data satisfactorily. |
BibTeX:
@article{Arslan-Alaton2009,
author = {Arslan-Alaton, I. and Kobya, M. and Akyol, A. and Bayramoglu, M.},
title = {Electrocoagulation of azo dye production wastewater with iron electrodes: process evaluation by multi-response central composite design},
journal = {Coloration Technology},
year = {2009},
volume = {125},
number = {4},
pages = {234--241},
doi = {10.1111/j.1478-4408.2009.00202.x}
}
|
| Erbil HY and Cansoy CE (2009), "Range of Applicability of the Wenzel and Cassie-Baxter Equations for Superhydrophobic Surfaces", Langmuir., December, 2009. Vol. 25(24), pp. 14135-14145. |
| Abstract: The Wenzel and Cassie-Baxter equations depending on the extent of liquid/solid interfacial contact area were generally used to estimate water contact angles on superhydrophobic surfaces. In this study, a simple method is proposed on the criterion to use the Wenzel and Cassie-Baxter equations to evaluate the contact angle results on superhydrophobic surfaces. In this method, the difference between the theoretical (geometric) and experimental contact angle-dependent Wenzel roughness parameter, Delta r(w), and Cassie-Baxter solid/liquid contact area fraction, Delta f(s)(CB) were determined, and the validity of these equations was evaluated. We used the data of eight recent publications where the water drop sits on square and cylindrical pillar structured superhydrophobic model surfaces. We evaluated the contact angle results of 166 patterned samples with our method. We also found that the effect of contact angle error margins was low to vary these parameters. In general, the use of the Wenzel equation was found to be wrong for most of the samples (74% of the samples for cylindrical and 58% for square pillar patterned surfaces), and the deviations from the theory were also high for the remaining (26% for cylindrical and 42% for square) samples, and it is concluded that the Wenzel equation cannot be used for superhydrophobic surfaces other than a few exceptions, especially for cylindrical patterns. For the Cassie-Baxter equation, two situations are possible: for positive Delta f(s)(CB), there is only a partial contact of the drop with the top solid surface, and, for negative Delta f(s)(CB), the penetration of the drop in between the pillars is possible, and thus the liquid drop is in contact with the lateral sides of the pillars. We found that 65% of the samples containing cylindrical pillars (52-77% with error margins) and 44% of the samples containing square pillars (38-50% with error margins) resulted in negative Delta f(s)(CB)(red) values. In addition, large deviations of experimental water contact angle results, theta(e)(r) from the theoretical theta(CB)(r) were also determined for most of the samples, indicating that the Cassie-Baxter equation should be applied to superhydrophobic surfaces with caution. |
BibTeX:
@article{Erbil2009,
author = {Erbil, H. Y. and Cansoy, C. E.},
title = {Range of Applicability of the Wenzel and Cassie-Baxter Equations for Superhydrophobic Surfaces},
journal = {Langmuir},
year = {2009},
volume = {25},
number = {24},
pages = {14135--14145},
doi = {10.1021/la902098a}
}
|
| Tosun A and Erbil HY ({2009}), "Evaporation rate of PTFE liquid marbles", APPLIED SURFACE SCIENCE., DEC 15, {2009}. Vol. {256}({5}), pp. 1278-1283. |
| Abstract: Liquid marbles are hydrophilic liquid drops encapsulated with a
hydrophobic powder. They behave as micro-reservoirs of liquids able to move rapidly without any leakage and are promising candidates to be applied in genetic analysis where 2D microfluidics and lab-on-a-chip methods are used. The manipulation of liquid marbles using gravitational, electrostatic and magnetic fields were recently investigated. In this work, we determined the evaporation rates of PTFE marbles formed by encapsulating PTFE micropowder on a water droplet in a closed chamber where relative humidity and temperature was kept constant. Evaporation rates of PTFE marbles were compared with the rates of pure water droplets in terms of evaporation resistance, phi parameter and it was found that PTFE marbles have longer life-time than water droplets so that phi values were found to increase regularly from 0.365 to 0.627 with the increase of RH of the evaporating medium. The barrier effect of PTFE microparticles at the water-air interface was more effective when water was evaporating slowly. PTFE water marbles have life-time of 26-60 min to retain their spherical shape under normal atmospheric conditions which is suitable for many promising applications in microfluidics, genetic analysis, electromagnetic actuators and valves. (C) 2009 Elsevier B. V. All rights reserved. |
BibTeX:
@article{Tosun2009,
author = {Tosun, A. and Erbil, H. Y.},
title = {Evaporation rate of PTFE liquid marbles},
journal = {APPLIED SURFACE SCIENCE},
year = {2009},
volume = {256},
number = {5},
pages = {1278--1283},
doi = {10.1016/j.apsusc.2009.10.035}
}
|
| Yuksek K, Koca Y and Sadikoglu H (2009), "Solution of counter diffusion problem with position dependent diffusion coefficent by using variational methods", Journal of Computational and Applied Mathematics., October, 2009. Vol. 232(2), pp. 285-294. |
| Abstract: Unsteady state counter diffusion problem with position dependent diffusion coefficient can be modeled using Fick's second law. A mathematical model was constructed and solved to quantitatively describe the dynamic behavior of solute diffusion through non-homogeneous materials where diffusion coefficient is a function of position. The eigenfunction expansion approach was utilized to solve the model. The eigenvalues and eigenfunction of the system were obtained using a variational method. It has been shown that position dependency of the material can be neglected if the thickness of the material is relatively small. Mathematical models were solved for different thicknesses and different diffusion coefficient functions. (C) 2009 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Yuksek2009,
author = {Yuksek, K. and Koca, Y. and Sadikoglu, H.},
title = {Solution of counter diffusion problem with position dependent diffusion coefficent by using variational methods},
journal = {Journal of Computational and Applied Mathematics},
year = {2009},
volume = {232},
number = {2},
pages = {285--294},
doi = {10.1016/j.cam.2009.06.009}
}
|
| Dandan M and Erbil HY (2009), "Evaporation Rate of Graphite Liquid Marbles: Comparison with Water Droplets", Langmuir., July, 2009. Vol. 25(14), pp. 8362-8367. |
| Abstract: Liquid marbles are liquid drops made completely nonwetting by encapsulating the drop with a hydrophobic powder. The absence of contact with the substrate avoids contamination problems and produces high marble displacement velocities. Liquid marbles behave as microreservoirs of liquids able to move without any leakage and are promising candidates to be applied in biomedical and genetic analysis where 2D microfluidics and lab-on-a-chip methods are used. The lifetime of a liquid marble depends on the chemical nature and particle size of the hydrophobic powder as well as the liquid used to form it. There is a need for chemically inert liquid marbles, which can be used over sufficiently long periods for industrial applications. In this work, we successfully synthesized graphite liquid marbles for the first time by encapsulating graphite micropowder on water droplets and determined their evaporation periods and useful lifetimes in constant relative humidity and temperature conditions in a closed chamber. The evaporation rates of graphite liquid marbles were compared with the rates of pure water droplets in the same conditions, and it was found that they had nearly twice the lifetime Of pure water droplets, The use of chemically inert graphite particles having electrical conductivity and dry lubrication properties to form a liquid marble may be a starting point for their successful use in microfluidics, genetic analysis, antifouling, wear-free micromachine, electromechanical actuator, and valve applications. |
BibTeX:
@article{Dandan2009,
author = {Dandan, M. and Erbil, H. Y.},
title = {Evaporation Rate of Graphite Liquid Marbles: Comparison with Water Droplets},
journal = {Langmuir},
year = {2009},
volume = {25},
number = {14},
pages = {8362--8367},
doi = {10.1021/la900729d}
}
|
| Guler S and Seker M (2009), "The Effect of Cinnamon and Guar Gum on Bacillus Cereus Population in Milk", Journal of Food Processing and Preservation., June, 2009. Vol. 33(3), pp. 415-426. |
| Abstract: Milk was inoculated with Bacillus cereus and the effect of cinnamon and guar gum on B. cereus counts in ultra high-temperature milk was examined by storing samples at 4 and 25C and determining microbial counts as total bacteria by plate count agar at 0, 7, 14 and 28 days. Cinnamon with or without guar gum did not significantly affect B. cereus count at 4C, but it reduced B. cereus counts of milk compared with B. cereus counts of control milk at 25C. Increasing cinnamon concentration from 0.5 to 1% increased antimicrobial effect at the starting of storage but did not affect final B. cereus count. Cinnamon shows antimicrobial activity with their essential oils penetrating through food medium to the microbial cell so the viscosity of food medium caused by stabilizers is a factor that can affect the diffusion of antimicrobial agents through medium to microorganisms and was determined by rotational viscometer. The viscosity of milk with guar gum (0.5%) was found higher than the viscosity of milk that was not including guar gum, but at the end of 28 days the B. cereus counts of milk with guar gum and cinnamon were not higher than the B. cereus counts of milk with cinnamon alone at 25C. |
BibTeX:
@article{Guler2009,
author = {Guler, S. and Seker, M.},
title = {The Effect of Cinnamon and Guar Gum on Bacillus Cereus Population in Milk},
journal = {Journal of Food Processing and Preservation},
year = {2009},
volume = {33},
number = {3},
pages = {415--426}
}
|
| Yoruc ABH and Koca Y (2009), "Double Step Stirring: A Novel Method for Precipitation of Nano-sized Hydroxyapatite Powder", Digest Journal of Nanomaterials and Biostructures., March, 2009. Vol. 4(1), pp. 73-81. |
| Abstract: The effect of three different stirring techniques (magnetic, ultrasonic and double-step stirring) on the properties of hydroxyapatite (HA) prepared from calcium hydroxide [Ca(OH)(2)] and phosphoric acid [H(3)PO(4)] was investigated. The employed precipitation processes were found to be suitable for the production of nano-sized pure HA powders. Sample characterization was achieved by powder X-ray diffraction (XRD), Fourier transformed infrared (FT-IR) transmission spectroscopy, scanning electron microscopy (SEM), density and surface area measurements. The double-step stirring technique played an important role to progress the homogenous reaction and the preparation of pure and fine HA powder. |
BibTeX:
@article{Yoruc2009,
author = {Yoruc, A. B. H. and Koca, Y.},
title = {Double Step Stirring: A Novel Method for Precipitation of Nano-sized Hydroxyapatite Powder},
journal = {Digest Journal of Nanomaterials and Biostructures},
year = {2009},
volume = {4},
number = {1},
pages = {73--81}
}
|
| Dizge N, Aydiner C, Imer DY, Bayramoglu M, Tanriseven A and Keskinlera B (2009), "Biodiesel production from sunflower, soybean, and waste cooking oils by transesterification using lipase immobilized onto a novel microporous polymer", Bioresource Technology., March, 2009. Vol. 100(6), pp. 1983-1991. |
| Abstract: This study aims at carrying out lipase-catalyzed synthesis of fatty acid methyl esters (biodiesel) from various vegetable oils using lipase immobilized onto a novel microporous polymeric matrix (MPPM) as a low-cost biocatalyst. The research is focused on three aspects of the process: (a) MPPM synthesis (monolithic, bead, and powder forms), (b) microporous polymeric biocatalyst (MPPB) preparation by immobilization of lipase onto MPPM, and (c) biodiesel production by MPPB. Experimental planning of each step of the study was separately carried out in accordance with design of experiment (DoE) based on Taguchi methodology. Microporous polymeric matrix (MPPM) containing aldehyde functional group was synthesized by polyHIPE technique using styrene, divinylbenzene, and polyglutaraldehyde. Thermomyces lanuginosus lipase was covalently attached onto MPPM with 80%, 85%, and 89% immobilization efficiencies using bead, powder, and monolithic forms, respectively. Immobilized enzymes were successfully used for the production of biodiesel using sunflower, soybean, and waste cooking oils. It was shown that immobilized enzymes retain their activities during 10 repeated batch reactions at 25 degrees C, each lasting 24 h. Since the developed novel method is simple yet effective, it could have a potential to be used industrially for the production of chemicals requiring immobilized lipases. (c) 2008 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Dizge2009,
author = {Dizge, N. and Aydiner, C. and Imer, D. Y. and Bayramoglu, M. and Tanriseven, A. and Keskinlera, B.},
title = {Biodiesel production from sunflower, soybean, and waste cooking oils by transesterification using lipase immobilized onto a novel microporous polymer},
journal = {Bioresource Technology},
year = {2009},
volume = {100},
number = {6},
pages = {1983--1991},
doi = {10.1016/j.biortech.2008.10.008}
}
|
| Aydiner C, Bayramoglu M, Keskinler B and Ince O (2009), "Nickel Removal from Waters Using a Surfactant-Enhanced Hybrid Powdered Activated Carbon/Microfiltration Process. II. The Influence of Process Variables", Industrial & Engineering Chemistry Research., January, 2009. Vol. 48(2), pp. 903-913. |
| Abstract: This study focused on the removal of nickel ions from aqueous solution using a surfactant-enhanced (SE) powdered activated carbon (PAC)/microfiltration (MF) hybrid membrane process. The main objective of the research is to investigate the technical performance of the process under the influences of all relevant process variables namely process time, recycling time, pH, temperature, PAC concentration, surfactant concentration, nickel concentration, cross-flow velocity, and transmembrane pressure, thus to reveal its applicability. to water problems involved in heavy metal pollution. The concentrations of PAC, surfactant, metal, and HI ion were determined as significant process stream variables, while transmembrane pressure and temperature came into prominence as significant operating variables. ANOVA calculations indicated that the total influences of these six variables on process performance realized in a range of about 93-98%. Nickel concentration and PAC amount in the feed were established as the most influential variables for nickel rejection, and surfactant rejection and permeate flux, respectively. The increase of PAC from 0.1 to 4 g/L led to a flux decline of about 60%. The most critical parameter for process performance was the mass ratio of PAC to surfactant (PAC/surfactant) per unit mass of metal removed. The process which may be effectively operated in continuous cross-flow filtration mode within a short filtration time of 30 min has crucial advantages compared to high pressure driven membrane processes and offers a promising alternative to remove heavy metal pollutants from drinking waters and metal bearing wastewaters. |
BibTeX:
@article{Aydiner2009,
author = {Aydiner, C. and Bayramoglu, M. and Keskinler, B. and Ince, O.},
title = {Nickel Removal from Waters Using a Surfactant-Enhanced Hybrid Powdered Activated Carbon/Microfiltration Process. II. The Influence of Process Variables},
journal = {Industrial & Engineering Chemistry Research},
year = {2009},
volume = {48},
number = {2},
pages = {903--913},
doi = {10.1021/ie8004308}
}
|
| Ozdemir M, Ozen BF, Dock LL and Floros JD (2008), "Optimization of osmotic dehydration of diced green peppers by response surface methodology", Lwt-food Science and Technology., December, 2008. Vol. 41(10), pp. 2044-2050. |
| Abstract: Osmotic dehydration of diced green peppers was optimized with respect to temperature (20-40 degrees C), time (15-600 min), salt (0-10 g/100 g) and sorbitol (0-10 g/100 g) concentrations through response surface methodology. Water loss (WL), solids gain (SG), salt uptake (SA) and sorbitol uptake (SO) were the responses in a 2 4 Central composite rotatable design. Models developed for all responses were significant (p <= 0.01) without significant lack of fit. Results suggested that optimum processing conditions of 5.5 g salt/100 g and 6 g sorbitol/100 g at 30 degrees C after 240 min would result in WL = 23.3%, SG = 4.1%, SA = 8 g/100 g dry pepper and SO = 2.4 g/100 ml extract. (C) 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Ozdemir2008,
author = {Ozdemir, M. and Ozen, B. F. and Dock, L. L. and Floros, J. D.},
title = {Optimization of osmotic dehydration of diced green peppers by response surface methodology},
journal = {Lwt-food Science and Technology},
year = {2008},
volume = {41},
number = {10},
pages = {2044--2050},
doi = {10.1016/j.lwt.2008.01.010}
}
|
| Cakmakci M, Kinaci C and Bayramoglu M (2008), "Adaptive Neuro-Fuzzy Modeling of Head Loss in Iron Removal with Rapid Sand Filtration", Water Environment Research., December, 2008. Vol. 80(12), pp. 2268-2275. |
| Abstract: Breakthrough and terminal head loss are the main parameters that determine the performance of rapid sand filters. Carman-Kozeny and Ergun equations can be applied to estimate head loss, but can only be applied to clean filter beds. Elaborated models are needed to predict head loss in dirty filters. In this study, a neuro-fuzzy modeling approach was proposed to estimate head loss in dirty filters. Hydraulic loading rate, influent iron concentration, bed porosity, and operating time were selected as input variables. Various types of membership functions were tried. Two rule-base generation methods-subtractive clustering and grid partition were used for a first-order, Sugeno-type inference system. Using 11 rules and the grid-partition method, an optimum rule base set was developed and the lowest root mean squared error (RMSE) was obtained. Tap and deionized waters were used to obtain testing RMSE values of 1.094 and 0.926, respectively. The fit between experimental results and model outputs was excellent, with the multiple correlation coefficient ( R 2) greater than 0.99. Based on these findings, the authors conclude that neuro-fuzzy modeling may successfully be used to predict filter head loss. Water Environ. Res., 80, 2268 ( 2008). |
BibTeX:
@article{Cakmakci2008,
author = {Cakmakci, M. and Kinaci, C. and Bayramoglu, M.},
title = {Adaptive Neuro-Fuzzy Modeling of Head Loss in Iron Removal with Rapid Sand Filtration},
journal = {Water Environment Research},
year = {2008},
volume = {80},
number = {12},
pages = {2268--2275},
doi = {10.2175/106143008X304659}
}
|
| Akyol A and Bayramoglu M (2008), "The degradation of an azo dye in a batch slurry photocatalytic reactor", Chemical Engineering and Processing., November, 2008. Vol. 47(12), pp. 2150-2156. |
| Abstract: The photocatalytic degradation of a commercial azo-reactive textile dye, Remazol Red F-3B, has been investigated in a batch slurry reactor using semiconductor catalysts like, ZnO and TiO(2), and two UV sources emitting mainly at 254 and 365 rim. Non-irradiated catalysts and non-catalyzed UV irradiation have negligible effect on the dye degradation. Initial pH. dye concentration, light power and catalyst loading as well as the catalyst type and UV wavelength are considered as process variables. The results showed that decolorization and TOC removal efficiencies of ZnO are higher under 365 nm UV. On the other hand, when two photocatalysts are compared, the decolorization performance of ZnO is higher than TiO(2) under 365 nm UV. while TiO(2) performs better under 254 nm UV. Furthermore, from the TOC removal point, TiO(2) performs better than ZnO irrespective of the UV wavelength. TiO(2) irradiated under 254 nm UV degrades successfully both benzene and naphthalene derivatives. (C) 2007 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Akyol2008,
author = {Akyol, A. and Bayramoglu, M.},
title = {The degradation of an azo dye in a batch slurry photocatalytic reactor},
journal = {Chemical Engineering and Processing},
year = {2008},
volume = {47},
number = {12},
pages = {2150--2156},
doi = {10.1016/j.cep.2007.11.002}
}
|
| Kobya M, Ciftci C, Bayramoglu M and Sensoy MT (2008), "Study on the treatment of waste metal cutting fluids using electrocoagulation", Separation and Purification Technology., May, 2008. Vol. 60(3), pp. 285-291. |
| Abstract: Electrocoagulation (EC) technique is applied for the treatment of waste metal cutting fluids (WMCFs) characterized by high COD and TOC concentration, discharged from metal manufacturing facilities including automotive engine, transmission, and stamping plants. The effects of initial pH, current density and operating time on the performance of EC are investigated by using sacrificial A] and Fe electrodes. Upon treatment by EC, the COD of WMCF is reduced by 93% and the TOC is reduced by 78% for At electrode at pH 5.0, current density of 60 A/m(2) and operating time of 25 min. For Fe electrode, the reduction in COD is 92% and reduction in TOC is 82% at pH 7.0, current density of 60 A/m(2) and operating time of 25 min. Under optimal operating conditions, the operating costs are calculated as 0.497 /m(3) (0.023 /kg removed COD or 0.144 /kg removed TOC) for Fe electrode, and 0.768 /m(3) (0.036 /kg removed COD or 0.228/kg removed TOC) for Al electrode. Fe electrode is found to be more efficient than At electrode in terms of parameters such as COD and TOC removal efficiencies and operating costs. (c) 2007 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Kobya2008,
author = {Kobya, M. and Ciftci, C. and Bayramoglu, M. and Sensoy, M. T.},
title = {Study on the treatment of waste metal cutting fluids using electrocoagulation},
journal = {Separation and Purification Technology},
year = {2008},
volume = {60},
number = {3},
pages = {285--291},
doi = {10.1016/j.seppur.2007.09.003}
}
|
| Ozdemir M and Floros JD (2008), "Optimization of edible whey protein films containing preservatives for water vapor permeability, water solubility and sensory characteristics", Journal of Food Engineering., May, 2008. Vol. 86(2), pp. 215-224. |
| Abstract: The effect of protein, sorbitol, beeswax and potassium sorbate concentrations in whey protein films on their water vapor permeability, water solubility and organoleptic properties was investigated using mixture response surface methods. All factors including protein, sorbitol, beeswax and potassium sorbate influenced water vapor permeability and water solubility of the films. Beeswax was the most important factor influencing the stickiness and appearance of the films. Amount of protein (50-65%, w/w) had no effect on stickiness and appearance, while the amount of sorbitol (35-50%, w/w) in the films had no influence on appearance. Mixture proportions of protein = 0.53, sorbitol = 0.38, beeswax = 0.08 and potassium sorbate = 0.01 would yield an edible film with minimum stickiness, water vapor permeability <= 9 g mm m(-2) h(-1) kPa(-1), water solubility >= 39% and appearance score >= 80. (C) 2007 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Ozdemir2008a,
author = {Ozdemir, M. and Floros, J. D.},
title = {Optimization of edible whey protein films containing preservatives for water vapor permeability, water solubility and sensory characteristics},
journal = {Journal of Food Engineering},
year = {2008},
volume = {86},
number = {2},
pages = {215--224},
doi = {10.1016/j.jfoodeng.2007.09.028}
}
|
| Emer Z, Akbas MY and Ozdemir M (2008), "Bactericidal activity of ozone against Escherichia coli in whole and ground black-peppers", Journal of Food Protection., May, 2008. Vol. 71(5), pp. 914-917. |
| Abstract: The effects of different ozone concentrations and ozonation times on the inactivation of Escherichia coli and on the organoleptic properties of whole and ground black peppers were determined. Black peppers were exposed to three different ozone concentrations (0.1, 0.5, and 1.0 ppm) for different periods (0 to 360 min) at 85% +/- 3% relative humidity (RH) and 25 +/- 0.5 degrees C. An similar to 7-log CFU/g reduction of E. coli in whole black peppers was achieved by treating the samples with 0.1, 0.5, or 1.0 ppm of ozone for 360, 240, or 120 min, respectively. E. coli populations in ground black peppers were reduced from an initial count of about 7.5 log CFU/g to 1 log CFU/g after 360 min at 0.1 - and 0.5-ppm ozone concentrations, whereas the same microbial reduction was obtained after 240 min at 1.0-ppm ozone concentration. An ozone concentration of 0.1 ppm for 360 min was found to be appropriate to inactivate E. coli in whole and ground black peppers without alteration of the organoleptic properties. No significant differences (P >= 0.05) were present in the bitterness, flavor, odor, color, or overall acceptability values of the whole and ground black peppers treated with 0.1 ppm of ozone for up to 360 min. |
BibTeX:
@article{Emer2008,
author = {Emer, Z. and Akbas, M. Y. and Ozdemir, M.},
title = {Bactericidal activity of ozone against Escherichia coli in whole and ground black-peppers},
journal = {Journal of Food Protection},
year = {2008},
volume = {71},
number = {5},
pages = {914--917}
}
|
| Mert O, Doganci E, Erbil HY and Dernir AS ({2008}), "Surface characterization of poly(L-lactic acid)-methoxy poly(ethylene glycol) diblock copolymers by static and dynamic contact angle measurements, FTIR, and ATR-FTIR", LANGMUIR., FEB 5, {2008}. Vol. {24}({3}), pp. 749-757. |
| Abstract: The surface composition and surface free energy properties of two types
of amphiphilic and semicrystalline diblock copolymers consisting of poly(L-lactic acid) coupled to (methoxy poly(ethylene glycol) (PLLA-MePEG) having differing block lengths of PEG were investigated by using static and dynamic contact angle measurements, transmission Fourier infrared spectroscopy (FTIR), and attenuated total reflection spectroscopy (ATR-FTIR) and compared with results obtained from PLLA and MePEG homopolymers. The contact angle results were evaluated by using the van Oss-Good method (acid-base method), and it was determined that the Lewis base surface tension coefficient (gamma(-)) of the copolymers increased with an increase of the PEG molar content at the copolymer surface. This result is in good agreement with the transmission FTIR and ATR-FTIR results but not proportional to them, indicating that the surfaces of the copolymers are highly mobile and that the molecular rearrangement takes place upon contact with a polar liquid drop. The dynamic contact angle measurements showed that the strong acid-base interaction between the oxygen atoms in the copolymer backbone of the relatively more hydrophilic PEG segments with the Lewis acidic groups of the polar and hydrogen-bonding water molecules enabled the surface molecules to restructure (conformational change) at the contact area, so that the PEG segments moved upward, whereas the apolar methyl pendant groups of PLLA segments buried downward. |
BibTeX:
@article{Mert2008,
author = {Mert, O. and Doganci, E. and Erbil, H. Y. and Dernir, A. S.},
title = {Surface characterization of poly(L-lactic acid)-methoxy poly(ethylene glycol) diblock copolymers by static and dynamic contact angle measurements, FTIR, and ATR-FTIR},
journal = {LANGMUIR},
year = {2008},
volume = {24},
number = {3},
pages = {749--757},
doi = {10.1021/la701966d}
}
|
| Akbas MY and Ozdemir M (2008), "Application of gaseous ozone to control populations of Escherichia coli, Bacillus cereus and Bacillus cereus spores in dried figs", Food Microbiology., February, 2008. Vol. 25(2), pp. 386-391. |
| Abstract: The effect of ozonation as a method to reduce Escherichia coli, Bacillus cereus and Bacillus cereus spores in dried figs was investigated. Dried figs were sprinkle inoculated with E coli, B. cereus and B. cereus spores in sterile bags at a level of 10(7) microorganism g(-1), mixed and allowed to dry for 1 h at 25 degrees C prior to ozonation. Inoculated samples were exposed to gaseous ozone in a chamber at 20 degrees C and 70% relative humidity. Ozone concentrations of 0.1, 0.5 and 1.0 ppm up to 360 min were used to inactivate E. coli and B. cereus while 1.0, 5.0, 7.0 and 9.0 ppm ozone concentrations for 360 min were used to treat R cereus spores. E. coli and B. cereus counts were decreased by 3.5 log numbers at 1.0 ppm. ozone concentration for 360 min ozone treatment. Up to 2 log reductions in the number of B. cereus spores were observed above 1.0 ppm ozone concentration at the end of 360 min of ozonation. No significant changes in color, pH and moisture content values of dried figs were observed after the ozonation treatments. No significant changes were found between sweetness, rancidity, flavor, appearance and overall palatability of ozonated and non-ozonated dried figs. Ozonation was found to be effective especially in reduction of vegetative cells in dried figs and a promising method for the decontamination of dried figs. (C) 2007 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Akbas2008,
author = {Akbas, M. Y. and Ozdemir, M.},
title = {Application of gaseous ozone to control populations of Escherichia coli, Bacillus cereus and Bacillus cereus spores in dried figs},
journal = {Food Microbiology},
year = {2008},
volume = {25},
number = {2},
pages = {386--391},
doi = {10.1016/j.fm.2007.09.007}
}
|
| Kobya M, Bayramoglu M and Eyvaz M (2007), "Techno-economical evaluation of electrocoagulation for the textile wastewater using different electrode connections", Journal of Hazardous Materials., September, 2007. Vol. 148(1-2), pp. 311-318. |
| Abstract: The bench scale of an electrocoagulation (EC) unit requires a detailed study discerning the effects of continuous variables such as pH, current density and operating time. and type variables such as electrode material and connection mode. This paper presents the results of the treatment of a textile wastewater by EC process. Two electrode materials, aluminum and iron, were connected in three modes namely, monopolar-parallel (MP-P), monopolar-serial (MP-S), and bipolar-serial (BP-S). COD and turbidity removals were selected as performance criteria. For a high COD removal, acidic medium is preferable for both electrode materials. For a high turbidity removal, acidic medium is preferable for aluminum. and neutral medium for iron. High current density is favorable for both removals in the case of iron. In the aluminum case, the current density exhibits a pronounced effect on COD removal, depending strongly on the connection mode, but it has a negligible effect on the turbidity removal. MP-P with iron or MP-S with aluminum electrode are suitable configurations in regard with the overall process performance. Moreover. process economy is as important as removal efficiencies during the process evaluation task. Various direct and indirect cost items including electrical, sacrificial electrodes, labor, sludge handling, maintenance and depreciation costs have been considered in the calculation of the total cost. The results show that MP-P mode is the most cost-effective for both electrode types. Both electrodes show similar results in reducing COD and turbidity, but iron is preferred as a low cost material. Finally, a comparative study showed that EC was faster and more economic; consumed less material and produced less sludge, and pH of the medium was more stabilized than chemical coagulation (CC) for similar COD and turbidity removal levels. For CC, FeCl3 was the preferable salt in view of its techno-economic performance. On the other hand, iron was the preferred electrode material in EC with MP-P system in experimental conditions such as, 30A m(-2) of current density and 15 min of time. the treatment cost was $ 0.245 m(-3). Consequently, the operating cost of CC was 3.2 times as high as the operating cost of EC. (C) 2007 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Kobya2007,
author = {Kobya, M. and Bayramoglu, M. and Eyvaz, M.},
title = {Techno-economical evaluation of electrocoagulation for the textile wastewater using different electrode connections},
journal = {Journal of Hazardous Materials},
year = {2007},
volume = {148},
number = {1-2},
pages = {311--318},
doi = {10.1016/j.jhazmat.2007.02.036}
}
|
| Bayramoglu M, Eyvaz M and Kobya M (2007), "Treatment of the textile wastewater by electrocoagulation Economical evaluation", Chemical Engineering Journal., April, 2007. Vol. 128(2-3), pp. 155-161. |
| Abstract: This paper presents the comparative results with respect to electrode configurations on the economic performance of treatment of textile wastewaters by electrocoagulation (EC) process. Aluminum and iron electrode materials were used as sacrificial electrode in parallel and serial connection modes. Various direct and indirect cost items including electrical, sacrificial electrodes, labor, sludge handling, maintenance and depreciation costs were considered in the calculation of the total cost per m(3) of wastewater taken from a textile plant with a capacity of 1000 m(3) per day. The results showed that monopolar-parallel mode (MP-P) was the most cost-effective for Fe and Al electrodes. These electrodes showed similar results in removal efficiency of COD and turbidity, but Fe electrode was preferred due to its low cost. pH 7 for Fe electrode and pH 5 for Al electrode were found suitable in terms of removal efficiency of COD and turbidity from textile wastewater. Meanwhile, 30 Am-2 of current density and 15 min of operating time were found to be sufficient for Fe and Al electrodes. Finally, a comparative study showed that EC was faster and more economic; consumed less material and produced less sludge, and pH of the medium was more stabilized as compared to chemical coagulation (CC) for percentage removal efficiency of COD and turbidity from textile wastewater. The treatment cost of EC at optimum conditions was 3.2 times cheaper than that of CC. (c) 2006 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Bayramoglu2007,
author = {Bayramoglu, M. and Eyvaz, M. and Kobya, M.},
title = {Treatment of the textile wastewater by electrocoagulation Economical evaluation},
journal = {Chemical Engineering Journal},
year = {2007},
volume = {128},
number = {2-3},
pages = {155--161},
doi = {10.1016/j.cej.2006.10.008}
}
|
| Sadikoglu H, Ozdemir M and Seker M (2006), "Freeze-drying of pharmaceutical products: Research and development needs", Drying Technology. Vol. 24(7), pp. 849-861. |
| Abstract: Significance of pharmaceutical formulation (choosing of correct excipients in optimal quantities), effects of glass transition temperature, importance of theoretical modeling of the process, benefits of optimal control, and the advantages of remote monitoring of the process are presented. Experimental and theoretical research and development needs for the freeze-drying of pharmaceutical products are proposed and discussed. |
BibTeX:
@article{Sadikoglu2006a,
author = {Sadikoglu, H. and Ozdemir, M. and Seker, M.},
title = {Freeze-drying of pharmaceutical products: Research and development needs},
journal = {Drying Technology},
year = {2006},
volume = {24},
number = {7},
pages = {849--861},
doi = {10.1080/07373930600734018}
}
|
| Sadikoglu H, Sen D and Ozdemir M (2006), "A mathematical model for potassium sorbate diffusion through whey protein films", Drying Technology. Vol. 24(1), pp. 21-29. |
| Abstract: A mathematical model was constructed and solved to quantitatively describe the dynamic behavior of the potassium sorbate diffusion through whey protein films. The model results were compared with the experimental data of the potassium sorbate diffusion through whey protein films, and excellent agreements between the experimental data and the model results are observed. The experimental data for potassium sorbate diffusion through whey protein films were used for mathematical model of potassium sorbate diffusion through whey protein films and the determination of both potassium sorbate and solvent diffusion coefficients. The diffusivities of potassium sorbate at 25 degrees C ranged from 4.12 to 9.34 x 10(-11) m(2)/s, while that of the solvent was between 1.38 and 8.74 x 10(-10) m(2)/s, depending on the film composition. |
BibTeX:
@article{Sadikoglu2006,
author = {Sadikoglu, H. and Sen, D. and Ozdemir, M.},
title = {A mathematical model for potassium sorbate diffusion through whey protein films},
journal = {Drying Technology},
year = {2006},
volume = {24},
number = {1},
pages = {21--29},
doi = {10.1080/07373930500538568}
}
|
| Ozcelik B and Bayramoglu M (2006), "The statistical modeling of surface roughness in high-speed flat end milling", International Journal of Machine Tools & Manufacture., October, 2006. Vol. 46(12-13), pp. 1395-1402. |
| Abstract: Surface roughness is one of the most important requirements in machining process. The surface roughness value is a result of the tool wear. When tool wear increase, the surface roughness also increases. The determination of the sufficient cutting parameters is a very important process obtained by means of both minimum surface roughness values and long tool life. The statistical models were developed to predict the surface roughness. This paper presents the development of a statistical model for surface roughness estimation in a high-speed flat end milling process under wet cutting conditions, using machining variables such as spindle speed, feed rate, depth of cut, and step over. First- and second-order models were developed using experimental results of a rotatable central composite design, and assessed by means of various statistical tests. The highest coefficient of correlation (R-adj(2)) (88%) was obtained with a 10-parameter second-order model. Meanwhile, a time trend was observed in residual values between model predictions and experimental data, reflecting the probable effect of the tool wear on surface roughness. Thus, in order to enhance the estimation capability of the model, another independent variable was included into the model to account for the effect of the tool wear, and the total operating time of the tool was selected as the most suitable variable for this purpose. By inserting this new variable as a linear term into the model, R-adj(2) was increased to 94% and a good fit was observed between the model predictions and supplementary experimental data. In this study, it was observed that, the order of significance of the main variables is as X-5>X-3>X-4>X-1>X-2 (total machining time, depth of cut, step over, spindle speed and feed rate, respectively). (C) 2005 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Ozcelik2006,
author = {Ozcelik, B. and Bayramoglu, M.},
title = {The statistical modeling of surface roughness in high-speed flat end milling},
journal = {International Journal of Machine Tools & Manufacture},
year = {2006},
volume = {46},
number = {12-13},
pages = {1395--1402},
doi = {10.1016/j.ijmachtools.2005.10.005}
}
|
| Bayramoglua M, Kobya M, Eyvaz M and Senturk E (2006), "Technical and economic analysis of electrocoagulation for the treatment of poultry slaughterhouse wastewater", Separation and Purification Technology., October, 2006. Vol. 51(3), pp. 404-408. |
| Abstract: Electrocoagulation (EC) is assessed by a preliminary technical and economic analysis for the treatment of poultry slaughterhouse wastewater (PSW). Chemical oxygen demand (COD) and oil-grease removal efficiencies, and total operating cost have been used for analysis purpose. Various direct and indirect cost items including electrical, sacrificial electrodes, labor, sludge handling, maintenance and depreciation costs have been considered in the calculation of the total cost. Iron and aluminum have been tested as sacrificial electrode material. Initial pH, current density and operating time were investigated as process variables. The experiments demonstrated the effectiveness of EC for the treatment of PSW. Aluminum electrode performed better in reducing the COD, with a removal efficiency as 93% in 25 at low initial pH, such as 3, and current density of 150 A/m(2). On the other hand, iron electrode was more successful in removing oil-grease with 98% efficiency, irrespective of the initial pH. From economic point of view, iron electrode is clearly preferable; the total operating cost is between 0.3 and 0.4/m(3), which is nearly half that of aluminum electrode. The total operating costs may also been calculated on the basis of /kg COD removed, which are 0.015 and 0.027 for iron and aluminum electrodes, respectively. (c) 2006 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Bayramoglua2006,
author = {Bayramoglua, M. and Kobya, M. and Eyvaz, M. and Senturk, E.},
title = {Technical and economic analysis of electrocoagulation for the treatment of poultry slaughterhouse wastewater},
journal = {Separation and Purification Technology},
year = {2006},
volume = {51},
number = {3},
pages = {404--408},
doi = {10.1016/j.seppur.2006.03.003}
}
|
| Akbas MY and Ozdemir M (2006), "Effect of different ozone treatments on aflatoxin degradation and physicochemical properties of pistachios", Journal of the Science of Food and Agriculture., October, 2006. Vol. 86(13), pp. 2099-2104. |
| Abstract: This study evaluated the efficiency of ozone for the degradation of aflatoxins in pistachio kernels and ground pistachios. Pistachios were contaminated with known concentrations of aflatoxin (AF) B-1, B-2, G(1), and G(2) Pistachio samples were exposed to gaseous ozone in a chamber at 5.0, 7.0 and 9.0 mgL(-1) ozone concentrations for 140 and 420 min at 20 degrees C and 70% RH. Aflatoxin degradation was determined by high performance liquid chromatography (HPLC). The efficiency of ozone for aflatoxin degradation in pistachios increased with increasing exposure time and ozone concentration. The results indicated that AFB(1) and total aflatoxins could be reduced by 23 and 24%, respectively, when pistachio kernels were ozonated at 9.0 mg L-1 ozone concentration for 420 min. Only a 5% reduction in AFB(1) and total aflatoxin levels could be achieved for ground pistachios under the same conditions. No significant changes occurred in pH, color, moisture content and free fatty acid values of pistachio kernels and ground pistachios. Fatty acid compositions of pistachios did not change significantly after the ozonation treatments. No significant changes were found between sweetness, rancidity, flavor, appearance and overall palatability of ozonated and non-ozonated pistachio kernels. Significant changes were observed in the organoleptic properties of ground pistachios, except rancidity, after 5.0 mgL(-1) ozone treatment for 140 min. Ozonation was found to be more effective for degrading aflatoxins in pistachio kernels than ground pistachios. (c) 2006 Society of Chemical Industry. |
BibTeX:
@article{Akbas2006,
author = {Akbas, M. Y. and Ozdemir, M.},
title = {Effect of different ozone treatments on aflatoxin degradation and physicochemical properties of pistachios},
journal = {Journal of the Science of Food and Agriculture},
year = {2006},
volume = {86},
number = {13},
pages = {2099--2104},
doi = {10.1002/jsfa.2579}
}
|
| Yildirim Y and Bayramoglu M (2006), "Adaptive neuro-fuzzy based modelling for prediction of air pollution daily levels in city of Zonguldak", Chemosphere., June, 2006. Vol. 63(9), pp. 1575-1582. |
| Abstract: Air pollution is a growing problem arising from domestic heating, high density of vehicle traffic, electricity production, and expanding commercial and industrial activities, all increasing in parallel with urban population. Monitoring and forecasting of air quality parameters in the urban area are important due to health impact. Artificial intelligent techniques are successfully used in modelling of highly complex and non-linear phenomena. In this study, adaptive neuro-fuzzy logic method has been proposed to estimate the impact of meteorological factors on SO2 and total suspended particular matter (TSP) pollution levels over an urban area. The model forecasts satisfactorily the trends in SO2 and TSP concentration levels, with performance between 75-90% and 69-80 %, respectively. (c) 2005 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Yildirim2006,
author = {Yildirim, Y. and Bayramoglu, M.},
title = {Adaptive neuro-fuzzy based modelling for prediction of air pollution daily levels in city of Zonguldak},
journal = {Chemosphere},
year = {2006},
volume = {63},
number = {9},
pages = {1575--1582},
doi = {10.1016/j.chemosphere.2005.08.070}
}
|
| Kobya M, Senturk E and Bayramoglu M (2006), "Treatment of poultry slaughterhouse wastewaters by electrocoagulation", Journal of Hazardous Materials., May, 2006. Vol. 133(1-3), pp. 172-176. |
| Abstract: Treatment of poultry slaughterhouse wastewater (PSW) by electrocoagulation (EC) has been investigated batchwise in this paper. Effects of the process variables such as medium pH, electrode material, current density, and operating time are investigated on chemical oxygen demand (COD) and oil-grease removal efficiencies, electrical energy consumption, and sacrificial electrode consumption. The highest COD removal efficiency is reached with aluminum as 93%, and maximum oil-grease removal is obtained with iron electrodes as 98%. Combined use of both electrode materials in the EC unit may yield high process performances with respect to both COD and oil-grease removals. Further work needs to be carried out at pilot scale to assess the technical end economic feasibility of the process. (c) 2005 Elsevier B.V All rights reserved. |
BibTeX:
@article{Kobya2006,
author = {Kobya, M. and Senturk, E. and Bayramoglu, M.},
title = {Treatment of poultry slaughterhouse wastewaters by electrocoagulation},
journal = {Journal of Hazardous Materials},
year = {2006},
volume = {133},
number = {1-3},
pages = {172--176},
doi = {10.1016/j.jhazmat.2005.10.007}
}
|
| Kobya M, Demirbas E, Can OT and Bayramoglu M (2006), "Treatment of levafix orange textile dye solution by electrocoagulation", Journal of Hazardous Materials., May, 2006. Vol. 132(2-3), pp. 183-188. |
| Abstract: The decolorization of the levafix orange textile dye in aqueous solution by electrocoagulation using aluminum sacrificial anode has been investigated. The process performance is analyzed in terms of decolorization efficiency and the important cost-related parameters such as electrode and energy consumptions, as a function of initial pH, conductivity, current density, initial dye concentration and electrolysis time. The present study proves the effectiveness of electrochemical treatment for the textile dye solution. 95% decolorization efficiency may be obtained at suitable operating conditions such as; current density 100 A/m(2), operating time 12 min and initial pH 6.4. The corresponding electrode and energy consumptions during the electrolysis were found to be 1.8 kg Al/kg dye and 35 kWh/kg dye. (c) 2005 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Kobya2006a,
author = {Kobya, M. and Demirbas, E. and Can, O. T. and Bayramoglu, M.},
title = {Treatment of levafix orange textile dye solution by electrocoagulation},
journal = {Journal of Hazardous Materials},
year = {2006},
volume = {132},
number = {2-3},
pages = {183--188},
doi = {10.1016/j.jhazmat.2005.07.084}
}
|
| Seker M and Hanna MA (2006), "Sodium hydroxide and trimetaphosphate levels affect properties of starch extrudates", Industrial Crops and Products., May, 2006. Vol. 23(3), pp. 249-255. |
| Abstract: In addition to being consumed as food, starch is considered for replacement of petroleum-based plastics, but imparts negative effect like water absorption and solubilization in water. In this study, the effects of sodium hydroxide and sodium trimetaphosphate concentrations on the water absorption and solubility indices of starch cross-linked by sodium hydroxide and sodium were evaluated. Starch was granulated, and 0.3 kg granulated starch was mixed with 65 ml sodium hydroxide at three concentrations (0.2, 0.6, and 1.0 M), sodium trimetaphosphate at two levels (0.015 and 0.045 kg sodium trimetaphosphate corresponding to 5 and 15% of starch), and water to adjust moisture content to 40% (dry basis). The samples were extruded in a single-screw extruder at a barrel temperature of 130 degrees C and screw speed of 140 rpm. Phosphorus content and pasting viscosity of starch extrudates showed that starch was crosslinked with phosphorus that was incorporated into starch during extrusion. The extrusion and cross-linking of starch with 5% sodium trimetaphosphate reduced water absorption index, and increasing sodium trimetaphosphate percentage reduced water absorption index further at high levels of sodium hydroxide. On the other hand, the reduction in water solubility of starch extrudates required the extrusion of starch with more than 5% sodium trimetaphosphate, but increasing the sodium hydroxide level increased the water solubility index of extrudates. (C) 2005 Published by Elsevier B.V. |
BibTeX:
@article{Seker2006,
author = {Seker, M. and Hanna, M. A.},
title = {Sodium hydroxide and trimetaphosphate levels affect properties of starch extrudates},
journal = {Industrial Crops and Products},
year = {2006},
volume = {23},
number = {3},
pages = {249--255},
doi = {10.1016/j.indcrop.2005.08.002}
}
|
| Aydiner C, Bayramoglu M, Kara S, Keskinler B and Ince O (2006), "Nickel removal from waters using surfactant-enhanced hybrid PAC/MF process. I. The influence of system-component variables", Industrial & Engineering Chemistry Research., May, 2006. Vol. 45(11), pp. 3926-3933. |
| Abstract: This study takes aim at exploring the effectiveness of a surfactant-added powdered activated carbon/ microfiltration (PAC/MF) hybrid process in the removal of nickel ions from water and wastewater as a promising technology. For this aim, the influence of system-component variables related to membrane material and pore size, and adsorbent and surfactant types was investigated. Nickel rejection (R-M), surfactant rejection (R-S), and steady-state flux (J*) were taken into account for more elaborately assessing the technical performance of the process. It was determined that the use of a surfactant in this process is justified only above the critical micellar concentration (CMC). Despite the increasing of nickel rejection with the addition of surfactant into the hybrid membrane process, a considerable decrease in steady-state flux is a major drawback of process. The flux decline observed was strongly dependent on surfactant type. This was interpreted as being due to a secondary membrane layer formed by surfactant micelles on the surface and within the membrane pores. The flux decline could also be related to PAC layer formation. Membrane, adsorbent, and surfactant types seem to have the highest relative influence on R-M, R-S, and J*, respectively. As a conclusion, surfactant type and membrane pore size were established as having the biggest and the smallest total influence on process performance, respectively. |
BibTeX:
@article{Aydiner2006,
author = {Aydiner, C. and Bayramoglu, M. and Kara, S. and Keskinler, B. and Ince, O.},
title = {Nickel removal from waters using surfactant-enhanced hybrid PAC/MF process. I. The influence of system-component variables},
journal = {Industrial & Engineering Chemistry Research},
year = {2006},
volume = {45},
number = {11},
pages = {3926--3933},
doi = {10.1021/ie051237c}
}
|
| Akbas MY and Ozdemir M (2006), "Effectiveness of ozone for inactivation of Escherichia coli and Bacillus cereus in pistachios", International Journal of Food Science and Technology., May, 2006. Vol. 41(5), pp. 513-519. |
| Abstract: The effectiveness of ozone for the decontamination of Escherichia coli and Bacillus cereus in kernels, shelled and ground pistachios was investigated. Pistachios were inoculated with known concentrations of E. coli and B. cereus. Pistachio samples were exposed to gaseous ozone in a chamber at three different concentrations (0.1, 0.5 and 1.0 ppm) for various times (0-360 min) at 20 degrees C and 70% relative humidity. The effectiveness of ozone against E. coli and B. cereus increased with increasing exposure time and ozone concentration. The physico-chemical properties including: pH, free fatty acids and peroxide values, colour and fatty acid composition of pistachios did not change significantly after the ozonation treatments, except for the peroxide value of ground pistachios ozonized at 1.0 ppm for 360 min. Ozone concentration of 1.0 ppm was effective in reducing E. coli and B. cereus counts in kernels and shelled pistachios, while ozone concentrations < 1.0 ppm were found to be appropriate in reducing the number of both bacteria in ground pistachios without having any change in their physico-chemical properties. |
BibTeX:
@article{Akbas2006a,
author = {Akbas, M. Y. and Ozdemir, M.},
title = {Effectiveness of ozone for inactivation of Escherichia coli and Bacillus cereus in pistachios},
journal = {International Journal of Food Science and Technology},
year = {2006},
volume = {41},
number = {5},
pages = {513--519},
doi = {10.1111/j.1365-2621.2005.01099.x}
}
|
| Can OT, Kobya M, Demirbas E and Bayramoglu M (2006), "Treatment of the textile wastewater by combined electrocoagulation", Chemosphere., January, 2006. Vol. 62(2), pp. 181-187. |
| Abstract: Electrocoagulation (EC) due to some advantages over chemical coagulation is becoming a popular process to be used for wastewater treatment. The aim of this paper is to investigate the effect of initial addition of a chemical coagulant such as polyaluminum chloride (PAC) or alum on the COD removal efficiency of EC treatment of textile wastewaters. The two salts exhibited the same performance in chemical coagulation, but in the combined electrocoagulation (CEC), PAC was found to significantly enhance the COD removal rate and efficiency, depending on the amount of the total aluminum supplied, by initial addition and electrochemical generation. A comparative operating cost analysis was also given and it was found that with the same operating cost per mass of COD removed, CEC performance was 80%, in contrast to 23% with EC, in 5 min of operation. (c) 2005 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Can2006,
author = {Can, O. T. and Kobya, M. and Demirbas, E. and Bayramoglu, M.},
title = {Treatment of the textile wastewater by combined electrocoagulation},
journal = {Chemosphere},
year = {2006},
volume = {62},
number = {2},
pages = {181--187},
doi = {10.1016/j.chemosphere.2005.05.022}
}
|
| McHale G, Aqil S, Shirtcliffe N, Newton M and Erbil H ({2005}), "Analysis of droplet evaporation on a superhydrophobic surface", LANGMUIR., NOV 22, {2005}. Vol. {21}({24}), pp. 11053-11060. |
| Abstract: The evaporation process for small, 1-2-mm-diameter droplets of water
from patterned polymer surfaces is followed and characterized. The surfaces consist of circular pillars (5-15 mu m diameter) of SU-8 photoresist arranged in square lattice patterns such that the center-to-center separation between pillars is 20-30,mu m. These types of surface provide superhydrophobic systems with theoretical initial Cassie-Baxter contact angles for water droplets of up to 140-167 degrees, which are significantly larger than can be achieved by smooth hydrophobic surfaces. Experiments show that on these SU-8 textured surfaces water droplets initially evaporate in a pinned contact line mode, before the contact line recedes in a stepwise fashion jumping from pillar to pillar. Provided the droplets of water are deposited without too much pressure from the needle, the initial state appears to correspond to a Cassie-Baxter one with the droplet sitting upon the tops of the pillars. In some cases, but not all, a collapse of the droplet into the pillar structure occurs abruptly. For these collapsed droplets, further evaporation occurs with a completely pinned contact area consistent with a Wenzel-type state. It is shown that a simple quantitative analysis based on the diffusion of water vapor into the surrounding atmosphere can be performed, and estimates of the product of the diffusion coefficient and the concentration difference (saturation minus ambient) are obtained. |
BibTeX:
@article{McHale2005,
author = {McHale, G and Aqil, S and Shirtcliffe, NJ and Newton, MI and Erbil, HY},
title = {Analysis of droplet evaporation on a superhydrophobic surface},
journal = {LANGMUIR},
year = {2005},
volume = {21},
number = {24},
pages = {11053--11060},
doi = {10.1021/la0518795}
}
|
| Akyol A and Bayramoglu M (2005), "Photocatalytic degradation of Remazol Red F3B using ZnO catalyst", Journal of Hazardous Materials., September, 2005. Vol. 124(1-3), pp. 241-246. |
| Abstract: The photocatalytic degradation of aqueous solution of a commercial azo-reactive textile dye, Remazol Red F3B, has been investigated in a batch slurry reactor, in the presence of ZnO catalyst using two different UV light sources emitting at 254 nm and 365 nm. The effects of various process variables on degradation performance of the process have been investigated. The results showed that decolourization and total organic carbon (TOC) removal are both affected in the same manner by the solution pH in the pH range 6-10, showing maxima at pH 7 and pH 10. They are inversely related to the dye concentration, they increase in power-law with the light intensity. Decolourization is faster with 365 nm UV. TOC removal is not affected by UV wavelength in the initial period up to 20 min, after which it progresses faster under 365 nm UV radiation. These results indicate that the UV wavelength influences especially the degradation rate of the intermediate products generated during the initial period of the photocatalytic process. Finally, catalyst loading affects both efficiencies in the same trend, which are maximized at about 2 g/l catalyst loading. (c) 2005 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Akyol2005,
author = {Akyol, A. and Bayramoglu, M.},
title = {Photocatalytic degradation of Remazol Red F3B using ZnO catalyst},
journal = {Journal of Hazardous Materials},
year = {2005},
volume = {124},
number = {1-3},
pages = {241--246},
doi = {10.1016/j.hazmat.2005.05.006}
}
|
| Seker M ({2005}), "Selected properties of native or modified maize starch/soy protein mixtures extruded at varying screw speed", JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE., MAY, {2005}. Vol. {85}({7}), pp. 1161-1165. |
| Abstract: Mixtures of soy protein isolate and native or modified (crosslinked)
maize starch were extruded in a twin-screw extruder at screw speeds of 80, 120 and 160rpm and a moisture content of 250gkg(-1) (dry basis). Increasing screw speed did not affect the specific mechanical energy and water solubility and absorption indices but did affect the sectional expansion index and bulk density, as the flow rate of the feed was not held constant during extrusion. The sectional expansion indices of modified starch/soy protein mixtures were higher than those of native starch/soy protein mixtures, suggesting an effect of feed material in addition to phase transition on the expansion of extrudates containing soybean. Since the bulk densities of modified starch/soy protein mixtures were lower than those of native starch/soy protein mixtures, it appears that bulk densities of extrudates containing high percentages of soy protein can be reduced by the presence of crosslinked starch in the feed. © 2005 Society of Chemical Industry. |
BibTeX:
@article{Seker2005,
author = {Seker, M},
title = {Selected properties of native or modified maize starch/soy protein mixtures extruded at varying screw speed},
journal = {JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE},
year = {2005},
volume = {85},
number = {7},
pages = {1161--1165},
doi = {10.1002/jsfa.2086}
}
|
| Seker M ({2005}), "Residence time distributions of starch with high moisture content in a single-screw extruder", JOURNAL OF FOOD ENGINEERING., APR, {2005}. Vol. {67}({3}), pp. 317-324. |
| Abstract: Starch was extruded with sodium trimetaphosphate and sodium hydroxide in
a single-screw extruder with a mixing element at 28.5 35.5 and 41.2% moisture content (wet basis) and 90, 140 and 190 rpm screw speeds. The effects of moisture content of starch on mean residence time, spread of residence time distribution curve, and flow pattern were determined at three screw speeds. Increasing the screw speed reduced mean residence time at the moisture contents between 28.5% and 41.2%. Increasing the moisture content from 28.5% to 41.2% did not significantly affect the mean residence time. The spread of residence time distribution curve was reduced as screw speed was increased, but was not affected as moisture content was increased from 28.5% to 41.2%. The flow pattern was between plug flow and mixed flow. Two flow models were used to represent the flow pattern in the extruder. The parameters of each model were determined by a nonlinear regression, and the fitness of experimental data to the flow models was examined. (C) 2004 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Seker2005a,
author = {Seker, M},
title = {Residence time distributions of starch with high moisture content in a single-screw extruder},
journal = {JOURNAL OF FOOD ENGINEERING},
year = {2005},
volume = {67},
number = {3},
pages = {317--324},
doi = {10.1016/j.jfoodeng.2004.04.034}
}
|
| Seker M and Hanna M ({2005}), "Cross-linking starch at various moisture contents by phosphate substitution in an extruder", CARBOHYDRATE POLYMERS., MAR 15, {2005}. Vol. {59}({4}), pp. 541-544. |
| Abstract: Starch was extruded with sodium trimetaphosphate and sodium hydroxide in
a single-screw extruder with barrel and die temperature of 130 degrees C at three screw speeds of 40, 90, and 140 rpm and three moisture contents of 40, 55, and 70%. Time required for phosphorylation of starch in an extruder was found to be less than 2 min, and cross-linking of starch by phosphorus, which was incorporated into starch, was confirmed by paste viscosity of extruded starch. Cross-linking starch with 2.5% sodium trimetaphosphate did not significantly affect water absorption index, but reduced water solubility index so replacement of the process including mixing of starch with synthetic polymer in the extruder with another process including cross-linking of starch and then mixing with synthetic polymer can result in composite with lower solubility of starch. On the other hand, increasing moisture content of starch reduced both water absorption and solubility index of extrudates. (c) 2004 Elsevier Ltd. All rights reserved. |
BibTeX:
@article{Seker2005b,
author = {Seker, M and Hanna, MA},
title = {Cross-linking starch at various moisture contents by phosphate substitution in an extruder},
journal = {CARBOHYDRATE POLYMERS},
year = {2005},
volume = {59},
number = {4},
pages = {541--544},
doi = {10.1016/j.carbpol.2004.11.005}
}
|
| Oncel M, Ince M and Bayramoglu M ({2005}), "Leaching of silver from solid waste using ultrasound assisted thiourea method", ULTRASONICS SONOCHEMISTRY., FEB, {2005}. Vol. {12}({3}), pp. 237-242. |
| Abstract: Thiourea leaching of precious metals such as gold and silver from ores
has several advantages when compared with conventional cyanidation process. In recent years, the use of ultrasound in leaching processes is becoming increasingly popular in hydrometallurgy. This paper deals with combining these two techniques for silver leaching from solid waste of a cyanidation leach plant located in Kutahya, Turkey. The primary aim of this research is to assess the technical performance of the method. To achieve maximum leaching yield, eight process variables have been selected to estimate optimum process conditions by means of statistical factorial design and steepest ascent techniques. Laboratory-scale experiments showed that complete leaching of silver may be achieved by this process. (C) 2003 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Oncel2005,
author = {Oncel, MS and Ince, M and Bayramoglu, M},
title = {Leaching of silver from solid waste using ultrasound assisted thiourea method},
journal = {ULTRASONICS SONOCHEMISTRY},
year = {2005},
volume = {12},
number = {3},
pages = {237--242},
doi = {10.1016/j.ultsonch.2003.10.007}
}
|
| Kobya M, Demirbas E and Bayramoglu M ({2004}), "Modelling the effects of adsorbent dose and particle size on the adsorption of Cr(VI) ions from aqueous solutions", ADSORPTION SCIENCE & TECHNOLOGY. Vol. {22}({7}), pp. 583-594. |
| Abstract: Activated carbon was prepared from hazelnut shell with chemical
carbonization using concentrated sulphuric acid. The adsorption tests were carried out in an agitated batch system with a fixed initial Cr(VI) ion concentration and varying adsorbent particle sizes and doses. The adsorption of Cr(VI) ions correlated strongly with these two variables. Two simple empirical models were examined for predicting the percentage of Cr(VI) ion adsorbed. Both models exhibited good correlation coefficients. The best model was selected on the basis of the standard deviation between the calculated and experimental values. The Freundlich adsorption isotherm provided the best correlation for the adsorption of Cr(VI) ions onto the carbon. This isotherm was used to fit the experimental adsorption capacity data and allowed the model parameters to be calculated and correlated with the particle size. |
BibTeX:
@article{Kobya2004,
author = {Kobya, M and Demirbas, E and Bayramoglu, M},
title = {Modelling the effects of adsorbent dose and particle size on the adsorption of Cr(VI) ions from aqueous solutions},
journal = {ADSORPTION SCIENCE & TECHNOLOGY},
year = {2004},
volume = {22},
number = {7},
pages = {583--594},
doi = {10.1260/0263617042879465}
}
|
| Seker M and Harper J ({2004}), "Effects of soymilk, soybean flour, and cream addition into milk on composition and textural properties of Cheddar cheese", MILCHWISSENSCHAFT-MILK SCIENCE INTERNATIONAL. Vol. {59}({7-8}), pp. 389-392. |
| Abstract: Effects of addition of soybean flour and soybean milk with and without
cream on composition and textural properties of Cheddar cheese were investigated. Incorporation of soybean flour or soybean milk into milk increased the moisture content of cheese, but the moisture content of cheese obtained with milk including soybean flour and cream was lower than the moisture content of cheese obtained with milk including soybean flour. On the other hand, fat content of cheese obtained with milk including soybean flour was lower than fat content of control cheese prepared without soybean flour in milk. Presence of soybean flour in milk resulted in lower protein content in cheese, but richer amino acid composition and nutritional value in cheese produced with milk including soybean flour is expected because of different amino acid composition of soybean and milk proteins. Cheeses, which were produced by milk to which soybean flour was added, resulted in open texture and there was soy flavor in cheese. So, the percentage of soybean flour added to milk was reduced. Hardness of cheeses prepared with milk including soybean flour was found lower than that of control process cheese. |
BibTeX:
@article{Seker2004b,
author = {Seker, M and Harper, J},
title = {Effects of soymilk, soybean flour, and cream addition into milk on composition and textural properties of Cheddar cheese},
journal = {MILCHWISSENSCHAFT-MILK SCIENCE INTERNATIONAL},
year = {2004},
volume = {59},
number = {7-8},
pages = {389--392}
}
|
| Seker M ({2004}), "Distribution of the residence time in a single-screw extruder with differing numbers of mixing elements", INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY., DEC, {2004}. Vol. {39}({10}), pp. 1053-1060. |
| Abstract: Starch was extruded with sodium trimetaphosphate and sodium hydroxide in
a single-screw extruder at 40% moisture content and screw speeds of 90 and 140 r.p.m. The effect of screw configurations, which included one and two mixing elements, on mean residence time, spread of residence time distribution (RTD), and flow pattern were determined. Increasing the screw speed and reducing the number of mixing elements reduced mean residence time. Higher RTD spread values were obtained at a screw speed of 90 r.p.m. when compared with 140 r.p.m. and increasing the number of mixing elements in the screw increased the RTD spread. The flow pattern was between plug and mixed flow, and increasing the number of a mixing element in the screw did not significantly affect the flow pattern in the single-screw extruder. |
BibTeX:
@article{Seker2004,
author = {Seker, M},
title = {Distribution of the residence time in a single-screw extruder with differing numbers of mixing elements},
journal = {INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY},
year = {2004},
volume = {39},
number = {10},
pages = {1053--1060},
doi = {10.1111/j.1365-2621.2004.00888.x}
}
|
| Akyol A, Yatmaz H and Bayramoglu M ({2004}), "Photocatalytic decolorization of remazol red RR in aqueous ZnO suspensions", APPLIED CATALYSIS B-ENVIRONMENTAL., NOV 30, {2004}. Vol. {54}({1}), pp. 19-24. |
| Abstract: The photocatalytic decolorization of aqueous solutions of Remazol Red
RR, a commercial azo-reactive textile dye, in the presence of various semiconductor powder suspensions has been investigated in a quartz batch reactor with the use of artificial light sources (UV-C). ZnO and TiO2 have been found the most active photocatalysts; however ZnO indicated slightly higher efficiency. The effects of various process variables on decolorization performance of the process have been investigated. The results showed that the decolorization efficiency increases with increase in pH, attaining maximum value at pH 10 for ZnO. The zero-point charge for ZnO is 9.0 above which ZnO surface is negatively charged by adsorbed OH- ions, favoring the formation of strong oxidant OH* radicals. The efficiency is inversely related to the dye concentration; increasing dye concentration enhances dye adsorption on the active sites of the catalyst surface, and consequently hinders OH- adsorption on the same sites, this results with a decreasing OH* formation rate. (C) 2004 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Akyol2004,
author = {Akyol, A and Yatmaz, HC and Bayramoglu, M},
title = {Photocatalytic decolorization of remazol red RR in aqueous ZnO suspensions},
journal = {APPLIED CATALYSIS B-ENVIRONMENTAL},
year = {2004},
volume = {54},
number = {1},
pages = {19--24},
doi = {10.1016/j.apcatb.2004.05.021}
}
|
| Yatmaz H, Akyol A and Bayramoglu M ({2004}), "Kinetics of the photocatalytic decolorization of an Azo reactive dye in aqueous ZnO suspensions", INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH., SEP 15, {2004}. Vol. {43}({19}), pp. 6035-6039. |
| Abstract: The photocatalytic decolorization of Remazol Red RR, a commercial azo
reactive textile dye, in ZnO suspension, has been investigated in a quartz batch reactor with the use of artificial light source (UV-C). The reaction kinetics are modeled by pseudo-first-order rate law. Regression analysis related pseudo-first-order rate constant, k, to the catalyst loading, empirically as k proportional to [ZnO](0.6). The decolorization rate increases with increasing pH, attaining maximum value at pH 10. The rate constant is inversely related to the initial dye concentration, empirically according to the relation k proportional to [C-0](-1.5). Finally, the rate constant is found proportional to the square root of the light intensity as k proportional to [I] (0.5). These empirical models are therefore combined as k proportional to [ZnO](0.6) [Co](-1.5) [I](0.5). |
BibTeX:
@article{Yatmaz2004,
author = {Yatmaz, HC and Akyol, A and Bayramoglu, M},
title = {Kinetics of the photocatalytic decolorization of an Azo reactive dye in aqueous ZnO suspensions},
journal = {INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH},
year = {2004},
volume = {43},
number = {19},
pages = {6035--6039},
doi = {10.1021/ie049921z}
}
|
| Bayramoglu M, Kobya M, Can O and Sozbir M ({2004}), "Operating cost analysis of electrocoagulation of textile dye wastewater", SEPARATION AND PURIFICATION TECHNOLOGY., JUN 15, {2004}. Vol. {37}({2}), pp. 117-125. |
| Abstract: Electrocoagulation (EC) is an efficient method for textile wastewater
treatment. Researches are mainly focused on the technical performance of this process, while its economic aspect has been Usually neglected. This paper deals with a simplified operating cost analysis for the treatment of a textile wastewater by EC using iron and aluminium electrode materials. The effects of various parameters such as wastewater conductivity and pH, current density and operating time, on the operating cost have been discussed for two electrode materials, separately. (C) 2003 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Bayramoglu2004,
author = {Bayramoglu, M and Kobya, M and Can, OT and Sozbir, M},
title = {Operating cost analysis of electrocoagulation of textile dye wastewater},
journal = {SEPARATION AND PURIFICATION TECHNOLOGY},
year = {2004},
volume = {37},
number = {2},
pages = {117--125},
doi = {10.1016/j.seppur.2003.09.002}
}
|
| Seker M, Sadikoglu H and Hanna M ({2004}), "Properties of cross-linked starch produced in a single screw extruder with and without a mixing element", JOURNAL OF FOOD PROCESS ENGINEERING., MAR, {2004}. Vol. {27}({1}), pp. 47-63. |
| Abstract: Starch was extnided with sodium hydroxide and sodium trimetaphosphate in
order to cross-link it in a single-screw extruder with and without a mixing element at constant screw speed of 90 rpm in the first set of experiments and at similar mean residence time controlled by screw speed in the second set of experiments. For the screw without mixing element in the second set of experiments, screw speed was adjusted to give the similar residence time as the single-screw extnider with mixing element at 220 rpm. Phosphorus content and pasting curves of extrudates showed that starch was cross-linked during extrusion. Replacing the screw without mixing element by the screw with mixing element increased specific mechanical energy dissipation into starch, but there was not significant difference between water solubility and absorption indices of starch cross-linked in the single-screw extruder with and without the mixing element at constant screw speed in the first set of experiments and at similar mean residence time in the second set of experiments. |
BibTeX:
@article{Seker2004a,
author = {Seker, M and Sadikoglu, H and Hanna, MA},
title = {Properties of cross-linked starch produced in a single screw extruder with and without a mixing element},
journal = {JOURNAL OF FOOD PROCESS ENGINEERING},
year = {2004},
volume = {27},
number = {1},
pages = {47--63},
doi = {10.1111/j.1745-4530.2004.tb00622.x}
}
|
| Sayan E and Bayramoglu M ({2004}), "Statistical modeling and optimization of ultrasound-assisted sulfuric acid leaching of TiO2 from red mud", HYDROMETALLURGY., JAN, {2004}. Vol. {71}({3-4}), pp. 397-401. |
| Abstract: Ultrasound has proven to be a very effective tool for enhancing reaction
rates by inducing a number of chemical and mechanical effects on the reaction medium. In this study, the effect of ultrasound power on the sulfuric acid leaching of Ti from red mud has been investigated by statistically designed experiments. The effects of five parameters, ultrasound power, temperature, leaching time, acid concentration and solid to liquid ratio, on the leaching of TiO2, Al2O3 and Fe2O3 have been investigated. First-order models have been obtained by using 2(5-1) fractional factorial design. Auxiliary experiments for second-order models have been conducted according to an orthogonal central composite design. These second-order models have been used in a constrained optimization study which showed that both high and selective yields of TiO2 may be obtained under suitable process conditions. The major factors influencing TiO2 leaching were acid concentration and temperature, the other variables had comparatively small effects. The use of ultrasound resulted in a 20% increase in TiO2 leaching compared to identical conditions without ultrasound. (C) 2004 Elsevier B.V. All rights reserved. |
BibTeX:
@article{Sayan2004,
author = {Sayan, E and Bayramoglu, M},
title = {Statistical modeling and optimization of ultrasound-assisted sulfuric acid leaching of TiO2 from red mud},
journal = {HYDROMETALLURGY},
year = {2004},
volume = {71},
number = {3-4},
pages = {397--401},
doi = {10.1016/S0304-386X(03)00113-0}
}
|
| Yildirim Y, Bayramoglu M and Hasiloglu S ({2003}), "Prediction of sulfur dioxide daily levels in the city of Zonguldak using an adaptive neuro-fuzzy based method", FRESENIUS ENVIRONMENTAL BULLETIN. Vol. {12}({10}), pp. 1173-1179. |
| Abstract: Air pollution continues to be a major problem in many countries.
Mathematical models are useful in relating emissions to air quality under a variety of meteorological conditions and source emission concentrations over an urban area. Meanwhile, the forecasting capability of sophisticated models is limited to very large and complex terrains. In this study, an adaptive neuro-fuzzy logic method has been developed to estimate the impact of meteorological factors on SO2 pollution levels. The model satisfactorily forecasts the trends of SO2 concentration levels with a performance between 78-90%. |
BibTeX:
@article{Yildirim2003,
author = {Yildirim, Y and Bayramoglu, M and Hasiloglu, S},
title = {Prediction of sulfur dioxide daily levels in the city of Zonguldak using an adaptive neuro-fuzzy based method},
journal = {FRESENIUS ENVIRONMENTAL BULLETIN},
year = {2003},
volume = {12},
number = {10},
pages = {1173--1179}
}
|
| Sadikoglu H, Ozdemir M and Seker M ({2003}), "Optimal control of the primary drying stage of freeze drying of solutions in vials using variational calculus", DRYING TECHNOLOGY. Vol. {21}({7}), pp. 1307-1331. |
| Abstract: The problem of operating freeze drying of pharmaceutical products in
vials placed in trays of a freeze dryer to remove free water (in frozen state) at a minimum time was formulated as an optimal control problem. Two different types of freeze dryer designs were considered. In type I freeze dryer design, upper and lower plate temperatures were controlled together, while in type II freeze dryer design, upper and lower plate temperatures were controlled independently. The heat input to the material being dried and the drying chamber pressure were considered as control variables. Constraints were placed on the system state variables by the melting and scorch temperatures during primary drying stage. Necessary conditions of optimality for the primary drying stage of freeze drying process in vials are derived and presented. Furthermore, an approach for constructing the optimal control policies that would minimize the drying time for the primary drying stage was given. In order to analyze optimal control policy for the primary drying stage of the freeze-drying process in vials, a rigorous multi-dimensional unsteady state mathematical model was used. The theoretical approach presented in this work was applied in the freeze drying of skim milk. Significant reductions in the drying times of primary drying stage of freeze drying process in vials were obtained, as compared to the drying times obtained from conventional operational policies. |
BibTeX:
@article{Sadikoglu2003,
author = {Sadikoglu, H and Ozdemir, M and Seker, M},
title = {Optimal control of the primary drying stage of freeze drying of solutions in vials using variational calculus},
journal = {DRYING TECHNOLOGY},
year = {2003},
volume = {21},
number = {7},
pages = {1307--1331},
doi = {10.1081/DRT-120023182}
}
|
| Seker M, Sadikoglu H, Ozdemir M and Hanna M ({2003}), "Cross-linking of starch with reactive extrusion and expansion of extrudates", INTERNATIONAL JOURNAL OF FOOD PROPERTIES. Vol. {6}({3}), pp. 473-480. |
| Abstract: Starch was extruded in a single-screw extruder with sodium hydroxide and
three levels of sodium trimetaphosphate (STMP) as 5, 10, and 15% after moisture content was adjusted to 40%. The amount of phosphorus that was incorporated into starch during extrusion, paste viscosity, water solubility index, and sectional expansion index (SEI) of extrudates were determined. A pasting viscosity of phosphorylated starch showed that starch was cross-linked with phosphorus that was incorporated into starch. The cross-linking of starch with STMP and increasing the levels of STMP from 5 to 15% reduced the water solubility index and SEI of extrudates. |
BibTeX:
@article{Seker2003a,
author = {Seker, M and Sadikoglu, H and Ozdemir, M and Hanna, MA},
title = {Cross-linking of starch with reactive extrusion and expansion of extrudates},
journal = {INTERNATIONAL JOURNAL OF FOOD PROPERTIES},
year = {2003},
volume = {6},
number = {3},
pages = {473--480},
doi = {10.1081/JFP-120021453}
}
|
| Seker M, Sadikoglu H, Ozdemir M and Hanna M ({2003}), "Phosphorus binding to starch during extrusion in both single- and twin-screw extruders with and without a mixing element", JOURNAL OF FOOD ENGINEERING., OCT, {2003}. Vol. {59}({4}), pp. 355-360. |
| Abstract: The effect of a mixing element in single- and twin-screw extruders on
the amount of phosphorus incorporated into starch was investigated for chemical modification of starch that has applications in the food and paper industries. Starch was mixed with sodium hydroxide and sodium trimetaphosphate and then the mixture was extruded. Screw speeds, which result in approximately the same residence time in both single- and twin-screw extruders with and without a mixing element, were determined. Screw speeds of 220 rpm in a single-screw extruder with a mixing element, 180 rpm in a single-screw extruder without a mixing element, and 160 rpm in a twin-screw extruder with and without a mixing element resulted in similar residence times. The presence of a mixing element did not have an effect on vessel dispersion number and flow pattern in the single-screw extruder but it affected vessel dispersion number and changed the flow pattern in the twin-screw extruder. The amount of phosphorus bound to starch did not increase with the mixing element in single- and twin-screw extruders for a constant mean residence time. (C) 2003 Elsevier Science Ltd. All rights reserved. |
BibTeX:
@article{Seker2003,
author = {Seker, M and Sadikoglu, H and Ozdemir, M and Hanna, MA},
title = {Phosphorus binding to starch during extrusion in both single- and twin-screw extruders with and without a mixing element},
journal = {JOURNAL OF FOOD ENGINEERING},
year = {2003},
volume = {59},
number = {4},
pages = {355--360},
doi = {10.1016/S0260-8774(02)00494-6}
}
|
| Kaya M, Hasiloglu A, Bayramoglu M, Yesilyurt H and Ozok A ({2003}), "A new approach to estimate anthropometric measurements by adaptive neuro-fuzzy inference system", INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS., AUG, {2003}. Vol. {32}({2}), pp. 105-114. |
| Abstract: Eighteen anthropometric measurements were taken in standing and sitting
positions, from 387 subjects between 15 and 17 years old. ``Adaptive Neuro-Fuzzy Inference System (ANFIS)'' was used to estimate anthropometric measurements as an alternative to stepwise regression analysis. Six outputs (shoulder width, hip width, knee height, buttock-popliteal height, popliteal height, and height) were selected for estimation purpose. The results showed that the number of inputs required estimating outputs varied with sex difference. ANFIS perform better than stepwise regression method for both sex groups, as revealed by the standard deviations averaged over the six outputs: S-ANFIS = 0.776. S-Regression = 0.855 for boys and, S-ANFIS = 0.883, S-Regression = 1.027 for girls. |
BibTeX:
@article{Kaya2003,
author = {Kaya, MD and Hasiloglu, AS and Bayramoglu, M and Yesilyurt, H and Ozok, AF},
title = {A new approach to estimate anthropometric measurements by adaptive neuro-fuzzy inference system},
journal = {INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS},
year = {2003},
volume = {32},
number = {2},
pages = {105--114},
doi = {10.1016/S0169-8141(03)00042-8}
}
|
| Can O, Bayramoglu M and Kobya M ({2003}), "Decolorization of reactive dye solutions by electrocoagulation using aluminum electrodes", INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH., JUL 9, {2003}. Vol. {42}({14}), pp. 3391-3396. |
| Abstract: The removal of pollutants from effluents by electrocoagulation has
become an attractive method in recent years. This paper deals with the batch removal of the reactive textile dye Remazol Red RB 133 from an aqueous medium by the electrocoagulation method using aluminum electrodes. The effects of wastewater conductivity, initial pH, current density, stirring rate, dye concentration, and treatment time on the decolorization efficiency and energy consumption have been investigated. Aluminum hydroxypolymeric species formed during an earlier stage of the operation efficiently remove dye molecules by precipitation, and in a subsequent stage, AI(OH)3 flocs trap colloidal precipitates and make solid-liquid separation easier during the flotation stage. These stages of electrocoagulation must be optimized to design an economically feasible electrocoagulation process. |
BibTeX:
@article{Can2003,
author = {Can, OT and Bayramoglu, M and Kobya, M},
title = {Decolorization of reactive dye solutions by electrocoagulation using aluminum electrodes},
journal = {INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH},
year = {2003},
volume = {42},
number = {14},
pages = {3391--3396},
doi = {10.1021/ie020951g}
}
|
| Kobya M, Can O and Bayramoglu M ({2003}), "Treatment of textile wastewaters by electrocoagulation using iron and aluminum electrodes", JOURNAL OF HAZARDOUS MATERIALS., JUN 27, {2003}. Vol. {100}({1-3}), pp. 163-178. |
| Abstract: Treatment of textile wastewaters by electrocoagulation using iron and of
aluminum electrode materials has been investigated in this paper. The effects of relevant wastewater characteristics such as conductivity and pH, and important process variables such as current density and operating time on the chemical oxygen demand (COD) and turbidity removal efficiencies have been explored. Furthermore, the electrode and energy consumptions for each electrode have been calculated. The results show that iron is superior to aluminum as sacrificial electrode material, from COD removal efficiency and energy consumption points. (C) 2003 Elsevier Science B.V. All rights reserved. |
BibTeX:
@article{Kobya2003,
author = {Kobya, M and Can, OT and Bayramoglu, M},
title = {Treatment of textile wastewaters by electrocoagulation using iron and aluminum electrodes},
journal = {JOURNAL OF HAZARDOUS MATERIALS},
year = {2003},
volume = {100},
number = {1-3},
pages = {163--178},
doi = {10.1016/S0304-3894(03)00102-X}
}
|
| Yildirim Y, Demircioglu N, Kobya M and Bayramoglu M ({2002}), "A mathematical modeling of sulphur dioxide pollution in Erzurum City", ENVIRONMENTAL POLLUTION. Vol. {118}({3}), pp. 411-417. |
| Abstract: A non-linear simple air-quality model was developed by applying the
continuity equation for the air control volume over Erzurum city center and tested using daily average values Of SO2 and meteorological data obtained during the winter seasons in Erzurum, Turkey from 1994 to 1998. Model parameters are estimated by non-linear regression analysis. Agreement between model predictions and measured data was found very satisfactory with standard deviations less than 20 mug/m(3). (C) 2002 Elsevier Science Ltd. All rights reserved. |
BibTeX:
@article{Yildirim2002,
author = {Yildirim, Y and Demircioglu, N and Kobya, M and Bayramoglu, M},
title = {A mathematical modeling of sulphur dioxide pollution in Erzurum City},
journal = {ENVIRONMENTAL POLLUTION},
year = {2002},
volume = {118},
number = {3},
pages = {411--417},
doi = {10.1016/S0269-7491(01)00291-3}
}
|
| Okur H, Tekin T, Ozer A and Bayramoglu M (2002), "Effect of ultrasound on the dissolution of colemanite in H2SO4", HYDROMETALLURGY., December, 2002. Vol. 67(1-3), pp. 79-86. |
| Abstract: This paper deals with the dissolution of colemanite in sulfuric acid, in
the absence and presence of ultrasound. By nonlinear regression analysis, a modified Avrami-typeA equation was fitted to kinetic data and the activation energy was found to be 30 kJ/mol in both cases. The effect of ultrasound is on the pre-exponential factor A in the Arrhenius equation. An empirical relation is also given, which relates the rate constant to ultrasound power. (C) 2002 Elsevier Science B.V. All rights reserved. |
BibTeX:
@article{Okur2002,
author = {Okur, H and Tekin, T and Ozer, AK and Bayramoglu, M},
title = {Effect of ultrasound on the dissolution of colemanite in H2SO4},
journal = {HYDROMETALLURGY},
year = {2002},
volume = {67},
number = {1-3},
pages = {79--86},
doi = {10.1016/S0304-386X(02)00137-8}
}
|
| Kuslu S and Bayramoglu M ({2002}), "Microwave-assisted dissolution of pyrite in acidic ferric sulfate solutions", INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH., OCT 16, {2002}. Vol. {41}({21}), pp. 5145-5150. |
| Abstract: The use of microwaves in synthetic chemistry has gained greatly in
importance in the past 10 years. An observed accelerating effect of microwaves on reactions rates has been explained either by a specific microwave effect or by a superheating phenomenon. This paper considers the dissolution of pyrite mineral in acidic ferric sulfate solutions in the absence and presence of microwaves. For this purpose, a computer-controlled microwave experimental apparatus was designed in our laboratory. The experiments show that the reaction rate between pyrite and acidic ferric sulfate solution is chemically controlled and that the reaction order with respect to each Fe3+ and H2SO4 is equal to 0.5 for both classical and microwave heating; thus, the reaction mechanism is not affected by microwave irradiation. At the same time, the activation energies calculated as 33.43 and 18.72 kJ/mol in the classical and microwave systems, respectively, reveal the net effect of microwave on the activation energy. |
BibTeX:
@article{Kuslu2002,
author = {Kuslu, S and Bayramoglu, M},
title = {Microwave-assisted dissolution of pyrite in acidic ferric sulfate solutions},
journal = {INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH},
year = {2002},
volume = {41},
number = {21},
pages = {5145--5150},
doi = {10.1021/ie020203r}
}
|
| Okur H and Bayramoglu M (2001), "The effect of the liquid-phase activity model on the simulation ethyl acetate production by reactive distillation", INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH., August, 2001. Vol. 40(16), pp. 3639-3646. |
| Abstract: Reactive distillation is an attractive way of improving process
economics by combining distillation and reaction, especially for equilibrium-limited reactions such as esterification. Reactive systems are more nonideal than conventional ones, thus, they need elaborate models that consider the nonideality of the vapor and liquid phases. Among abundant liquid-phase activity models, modified versions of UNIFAC are cited as being well-suited for this purpose. In this paper, four activity models are compared by means of a simulation model applied to the production of ethyl acetate. It is found that the two versions of UNIFAC give similar results. |
BibTeX:
@article{Okur2001,
author = {Okur, H and Bayramoglu, M},
title = {The effect of the liquid-phase activity model on the simulation ethyl acetate production by reactive distillation},
journal = {INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH},
year = {2001},
volume = {40},
number = {16},
pages = {3639--3646},
doi = {10.1021/ie000329t}
}
|