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Öğe The Effect of Colemanite on Thermal Properties of Recycled Polyethylene(Polish Acad Sciences Inst Physics, 2019) Bilici, İbrahimBoron is known as a rare and one of the most important elements for future engineering. Boron is naturally present in nature in the form of minerals, such as tincal, ulexite, colemanite, boracite, datolite and so on. Besides of the healthy benefits, it has numerous application area from agricultural applications to space technology. The boron derived chemicals, such as borones, borates, borohydrides, boronic acids and other boron compounds, are applied from nano-to macroscale. In this study, usage of boron mineral was investigated as a raw material in colemanite form without any chemical treatment. For this purpose polyethylene-colemanite composites were produced and characterized thermally. Polyethylene was used as a binder and colemanite as a matrix material. Used materials were characterized before process via the Fourier transform infrared spectroscopy and differential scanning calorimetry. Thermomechanical analysis and limiting oxygen index tests were also performed in order to determine the thermal and inflammability properties of the composite. The results show that colemanite play an ultimate role in composites for flammable properties and mechanical performance. These properties can be controlled by proper adjustments of the amount of colemanite in the composite.Öğe Examination of sulphonated maleic anhydride-alt-styrene copolymer membrane's properties by proton exchange membrane fuel cell(2012) Şahin, Fatma; Basan, SatılmışThe most important element of proton exchange membrane fuel cell (PEMFC) is the proton-conduction properties of polymeric membranes. Polymeric membranes that can be compatible with PEMFC were synthesized using maleic anhydride (MA) and styrene monomers (S). The properties of the poly(MA-co-S) copolymer were studied. This is an abstract of a paper presented at the CHISA 2012 - 20th International Congress of Chemical and Process Engineering and PRES 2012 - 15th Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (Prague, Czech Republic 8/25-29/2012).Öğe Effect of carbon nanoparticles on the I V characteristics of dye doped nematic liquid crystal(Czech Society of Chemical Engineering, 2014) Akkurt, Fatih; Kaya, Nihan; Alıcılar, Ahmet[No abstract available]Öğe Modeling of blending of mineral base oils via artificial neural networks(Czech Society of Chemical Engineering, 2014) Karadurmuş, Erdal; Akyazı, Habib; Yüceer, Mehmet[No abstract available]Öğe Preparation and properties of biodegradable food packing films from corn starch blending with hemicelluloses particles(Czech Society of Chemical Engineering, 2014) Şahin, Fatma; Çakanyıldırım, Çetin[No abstract available]Öğe Investigation of reaction pathways and kinetics of turkish asphaltenes(Italian Association of Chemical Engineering - AIDIC, 2013) Akmaz, Solmaz; Deniz, Celal Utku; Yaşar, MuzafferIn this study, reaction kinetics of asphaltene fractions of petroleum feedstocks from field in southeastern part of Turkey were investigated. Asphaltene was fractionated from atmospheric residue of petroleum feedstock. Atmospheric petroleum residue was obtained by removing the distillates boiling up to 350 °C using atmospheric distillation. Asphaltenes were subjected to pyrolysis reactions at 350, 375 and 400 °C for holding times ranging from 10 and 120 min. Product fractions were separated as gas, maltene, remaining asphaltene and coke. The time and temperature dependence of product distributions were determined. Four-lump model was proposed to explain the reaction pathways. This kinetic model was described as a system of ordinary differential equations. In order to estimate the rate constants in these ODEs, a Matlab code has been developed. Order of reaction is another important subject for fitting, first-order for all reactions and second-order for all reactions were analyzed. Copyright © 2013, AIDIC Servizi S.r.l.Öğe Impact response of waste poly ethylene terephthalate (PET) composite plate(Springer New York LLC, 2017) Bilici, İbrahim; Kurşun, Ali; Deniz, MervePoly ethylene terephthalate (PET) is considered one of the most important engineering polymers for the last two decades due to its rapid growth of usage, aesthetic appearance, good light transmittance, and smooth surface. It is highly preferable for the food and soft drink bottle packaging industry because of its low gas permeability and recycling potential. For this reason, vast amount of PET’s is used daily and mandates an effective recycling process. The recycling of PET can be performed using two different methods, which are chemical and mechanical methods. In this study, chemical recycling method was chosen as a recycling method. Waste PET bottle evaluated as a binder for composite materials. Obtained glycolized products and binder are characterized by OH number (hydroxyl), acid number and FTIR. Then E-glass/recycle resin composite plates were manufactured via Vacuum Assisted Resin Transfer Molding (VARTM). Drop weigh tests were applied to measure the general mechanical and damage behavior of these composites. © The Society for Experimental Mechanics, Inc. 2017.Öğe River water quality model verification through a GIS based software(2009) Yetik, Mehmet Kazım; Yüceer, Mehmet; Berber, Rıdvan; Karadurmuş, ErdalResearch and development attempts on water quality models created valuable resources in the sense of model calibration and verification techniques. Recognizing the current degree of pollution in rivers and the importance of the sustainable water resources management, the interactive river monitoring appears to be at the center of recent focus. However the available information in this area is still far from expectations. On one side, the Geographical Information Systems (GIS) are gaining widespread acceptance and on the other side fast and reliable water quality models and parameter estimation techniques are becoming available. However, previous work on integrating water quality models and GIS is very limited. This work brings an integrated platform on which ArcMap as a GIS and a water quality model in Matlab™ are brought together in an interactive and user-friendly manner. The software developed allows the user to enter the data collected from the river, runs the dynamic model in the Matlab™ environment, predicts the values of pollution constituents along the river, extracts the results and displays the water quality on the map in different forms. The software thus provides a considerable ease in future real time application for on site river monitoring and environmental pollution assessment.Öğe Pore modification in porous ceramic membranes with sol-gel process and determination of gas permeability and selectivity(2010) Tüzün, Fatma Nihal; Arçevik, ErselSummary: The aim of the study was to investigate the variation in total surface area, porosity, pore size, Knudsen and surface diffusion coefficients, gas permeability and selectivity before and after the application of sol-gel process to porous ceramic membrane in order to determine the effect of pore modification. In this study, three different sol-gel process were applied to the ceramic support separately; one was the silica sol-gel process which was applied to increase porosity, others were silica-sol dip coating and silica-sol processing methods which were applied to decrease pore size. As a result of this, total surface area, pore size and porosity of ceramic support and membranes were determined by using BET instrument. In addition to this, Knudsen and surface diffusion coefficients were also calculated. After then, ceramic support and membranes were exposed to gas permeation experiments by using the CO2 gas with different flow rates. Gas permeability and selectivity of those membranes were measured according to the data obtained. Thus, pore surface area, porosity, pore size and Knudsen diffusion coefficient of membrane treated with silica sol-gel process increased while total surface area was decreasing. Therefore, permeability of ceramic support and membrane treated with silica sol-gel process increased, and selectivity decreased with increasing the gas flow rate. Also, surface area, porosity, pore size, permeability, selectivity, Knudsen and surface diffusion coefficients of membranes treated with silica-sol dip coating and silica-sol processing methods were determined. As a result of this, porosity, pore size, Knudsen and surface diffusion coefficients decreased, total surface area increased in both methods. However, viscous flow and Knudsen flow permeability were detected as a consequence of gas permeability test and Knudsen flow was found to be a dominant transport mechanism in addition to surface diffusive flow owing to the small pore diameter in both methods. It was observed that silica-sol processing method had lower pore diameter and higher surface diffusion coefficient than silica-sol dip coating method. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Öğe Preparation and swelling properties of zeolite-poly(2-hydroxyethyl methacrylate-co-acrylic acid) hydrogel composites(Polish Academy of Sciences, 2016) Aktı, Filiz; Boran, FilizZeolite-Poly(2-hydroxyethyl methacrylate (HEMA)-co-acrylic acid (AA)) hydrogel composite materials were synthesized by in situ free radical addition polymerization technique. The swelling values obtained highly for the hydrogel are synthesized at HEMA/AA monomer ratio value of 80/20. The hydrogel composites synthesized with zeolite having-90 ?m particle size and 20 wt% amount showed the highest swelling degree. Zeolite adding to the hydrogel structure increased the swelling values of hydrogel. Synthesized samples were characterized using a Fourier transform infrared spectrometer technique.Öğe Effect of surfactant types on the size of tin oxide nanoparticles(Polish Academy of Sciences, 2017) Boran, Filiz; Çetinkaya, Sevil; Şahin, Melike EkinIn this study, tin oxide (SnO2) nanoparticles were synthesized by hydrothermal method in the presence of hydrazine and ammonia by adding surfactant for 12 h in a Teflon autoclave at 100°C reaction temperature. Tin(II) chloride hydrate as an inorganic precursor, hexadecyl trimethyl ammonium bromide (CTAB), and tetrapropyl ammonium bromide (TPAB) as cationic, and sodium dodecyl sulfonate (SDS) as anionic surfactants were used. The results showed that the size and shape of nanoparticles depended on the surfactant types. The nanoparticles sizes between 17.5 and 19.7 nm were obtained by changing types of surfactants. Synthesized tin oxide nanoparticles were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and the Fourier transform infrared spectroscopy.Öğe Synthesis, characterization and sensing behavior of WO3 nanocrystalline powder for toluene vapor(Polish Academy of Sciences, 2017) Boran, Filiz; Çetinkaya, SevilTungsten oxide (WO3) nanocrystalline powder was successfully synthesized by direct precipitation technique starting from sodium tungstate dehydrate (Na2WO4•2H2O) as precursor at 80°C for 48 h. The morphological characteristics, distribution, and crystallite size of WO3 nanocrystalline powder were analysed by transmission electron microscopy, X-ray diffraction, and the Fourier transform infrared spectroscopy. According to transmission electron microscopy results, the mean particle size of WO3 nanocrystalline powder was approximately determined as 41.7 nm. The gas sensing performance of WO3 nanocrystalline powder for saturated toluene vapor was measured by two probe resistivity unit in a closed vessel at room temperature. In addition, WO3 nanocrystalline powder was able to respond the lowest concentration of 500 ppm. The results showed that the sample exhibited high sensitivity (93%) and good response reproducibility (0.93 + 5.5%) for toluene vapor.Öğe Corrosion behaviour and electrical conductivity of reinforced TiAl3 and B4C hybrid aluminium composites(Polish Academy of Sciences, 2017) Erek, H. B.; Özyürek, Dursun; Asan, AbdurrahmanIn this study, corrosion and electric conductivity of aluminum hybrid composites (in situ TiAl3 and ex situ B4C) produced by powder metallurgy are investigated. Hybrid (in situ and ex situ) aluminum composite powders are produced by adding different amounts of titanium and B4C into AA7075 alloy powders. After the hybrid composite powders are cold pressed (600 MPa), they are sintered in atmosphere controlled furnace at 580°C for 4 h. As a result of this study, it was observed that increase of B4C%(Ti constant) decreases density and increase of Ti%(B4C constant) increases the density of composites. It was determined that corrosion resistances (Rp) of hybrid composites decreased due to interface surfaces formed between the reinforcement phase and the matrix.Öğe Electrical conductivity and corrosion performances of in situ and ex situ AA7075 aluminum composites(Polish Academy of Sciences, 2017) Erek, H. B.; Özyürek, Dursun; Asan, AbdurrahmanThe present study investigates corrosion behaviors and electric conductivity of AA7075 in situ (TiAl3) and ex situ (B4C) composites produced by powder metallurgy method. In production of in situ composites, various amounts of Ti (2, 4 and 6%) are added to AA7075 and for production of ex situ composites, B4C (3, 6, and 9%) are added. Prepared in situ and ex situ composite powders were pre-shaped at 600 MPa pressure with cold pressing. Pre-shaped samples were sintered in the atmosphere-controlled furnace at 580°C for 4 h. Corrosion test of produced composites was conducted in 0.1 M H2SO4 solution. As a result of these analyses, corrosion examinations on in situ manufactured composites revealed that anode and cathode currents are close to each other and those composites do not exhibit different corrosion behaviors. Corrosion rate of B4C added ex situ composites increases by B4C rate (due to increase of density of current).Öğe Experimental and simulation study on structural characterization and hydrogen storage of metal organic structured compounds(Elsevier Ltd, 2016) Öztürk, Zeynel; Özken, Göksel; Köse, Dursun Ali; Asan, AbdurrahmanOne of the barrier for common usage of hydrogen energy system is storing hydrogen efficiently. Especially for mobile applications, it is very important to store hydrogen in small spaces reversibly. Metal-organic framework (MOF) structured materials step forward with the ability of reversible hydrogen storage which meet the storage targets. The MOF structured compounds were synthesized using Cu(II) and Zn(II) metals, trimesic acid (benzene 1,3,5 tricarboxylic acid) (TMA) and 1,10 phenantroline (Phen) building blocks. The compounds were activated thermally at 398 K for 4 days under a vacuum for sorption experiments. Then, DTA/TGA, FT-IR, powder-XRD, BET surface area and elemental analysis techniques were used to determine the molecular structures of the synthesized compound. Finally, the hydrogen storage properties were measured at 77 K and 1 bar of hydrogen pressure. In addition to experimental investigations, hydrogen adsorption characteristics and performances of the compounds were also determined with the molecular simulation calculations. It is found that the Cu(II) and Zn(II) compounds could uptake 2.652 wt. % (sim. 2.434 wt. %) and 1.383 wt. % (1.187 wt. %) respectively, at 77 K and 1 bar pressure. Consequently, hydrogen adsorption mechanism and capacities of the compounds clarified. And it is found out that the compounds have good storage performance in comparison to the previously reported MOFs. © 2015 Hydrogen Energy Publications LLC.Öğe Sno2/graphene nanocomposites with enhanced gas sensing performance(Trans Tech Publications Ltd, 2018) Boran, Filiz; Çetinkaya, SevilGraphene-Tin Oxide (G-SnO2) nanocomposites in different morphology were synthesized using tin (II) chloride (SnCl2) and graphene Oxide (GO) via hydrothermal process in the presence of hydrazine and ammonia by adding surfactant for 12 hours in a teflon autoclave at 100ºC reaction temperature. Poly(vinyl prolidon) (PVP) and poly(ethylene glycol) (PEG) were used as nonionic surfactants while hexadecyl trimethyl ammonium bromide (CTAB) and sodium dodecyl sulfonate (SDS) were utilized as cationic and anionic surfactants, respectively. The synthesized nanocomposites were characterized by XRD, FESEM, C-TEM and FT-IR. The gas sensing properties of the obtained samples to the vapors of various Volatile Organic Compounds (VOC), such as Ethanol, Methanol, Chloroform, Toluene and Acetone were also investigated at room temperature. The prepared G-SnO2 nanocomposites exhibited high detection performances for ethanol, chloroform and methanol. The nanocomposites could be used as sensor material for VOC gases. © 2018 Trans Tech Publications, Switzerland.Öğe Synthesis and characterization of modified diatomite-leaf-like cuO nanosheet composites(Trans Tech Publications Ltd, 2018) Boran, FilizIn this work, firstly we described the effect of freeze drying on modification of raw diatomite. And then, modified diatomite-leaf-like copper oxide (CuO) nanosheet composite was successfully prepared by surfactant-free in-situ chemical precipitation method. The structure, morphology and elemental analysis of CuO nanosheets and its composite were analyzed by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDAX). Dimensions of leaf-like CuO nanosheets were approximately determined as 160 nm in width, 320 nm in length and 20 nm in thickness. According to the EDAX spectrum, leaf-like CuO nanosheets composed of Cu and O atoms without any impurity and also uniformly covered the entire surface of modified diatomite. © 2018 Trans Tech Publications, Switzerland.Öğe Pesticide effect on kinetic properties of catalase enzyme(Hitit Üniversitesi, 2017) Erol, Kadir; Cebeci, Büşra; Köse, Kazım; Köse, Dursun AliCatalase is a metalloenzyme. Contains Cu(II) as the metal ion. It is a detoxification agent for the H2O2 compound and protects tissues and cells from oxidative damage [1]. Cryogels are synthetic materials generally used in adsorption and immobilization studies of late years. In this study, it is aimed to investigate how the activity of free and immobilized catalase enzyme will be changed by pesticides (DDE and DDT). This is very important to determine how enzyme activity is affected by environmental pollution. For the characterization of cryogels; swelling test, Fourier transform infrared spectroscopy (FT-IR) analysis, scanning electron microscopy (SEM) analysis.
