WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Effects of Span 60 Template and Freeze Drying on Zinc Borate Produced From Zinc Nitrate Hexahydrate and Borax Decahydrate(Taylor and Francis Ltd., 2022) Alp, Burcu; Alp, Burcu; Gönen, Mehmet; Balköse, Devrim; Atakul Savrık, Sevdiye; Balköse, Devrim; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyZinc borate is an important additive to polymers and lubricants. The process variables such as reactant concentration, presence of template in precipitating medium and drying method determine the composition and particle size of zinc borates. In the present study, zinc borate precipitate obtained by mixing aqueous zinc nitrate and borax decahydrate solutions was dried either by conventional method or by freeze drying. The products were well characterized by advanced methods. Zinc borate from 1 mol dm(-3) reactants had (2.1 +/- 0.5)x(2.5 +/- 0.5)x(1.3 +/- 0.2) mu m and (0.5 +/- 0.1)x(1.3 +/- 0.1)x(0.028 +/- 0.01) mu m dimensions by conventional and freeze drying respectively. Individual particles smaller in size is obtained since the particles are not agglomerated due to absence of surface tension of liquid water for case of freeze drying. Planar particles agglomerated into 20 to 60 mu m crystals in the presence of template Span 60 in 1 mol dm(-3) reactants for conventional drying. Nano zinc borate particles with primary particle size of (46 +/- 9) nm were obtained by decreasing the reactant concentration to 0.1 mol dm(-3). The primary particle size was decreased to (40 +/- 3) nm by addition of Span 60 to dilute solutions. However zinc borate nanoparticles obtained from dilute solutions adhered to each other forming agglomerates during conventional drying. Their freeze drying would allow formation of a freely flowing nano powder.Book Part Key Engineering Materials Volume I: Current State of the Art on Novel Materials(Taylor and Francis Ltd., 2014) Balköse, Devrim; Balköse, Devrim; Horak, Daniel; Soltes, Ladislav; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology[No abstract available]Book Part Aluminium-Coated Polymer Films as Infrared Light Shields for Food Packing(Taylor and Francis Ltd., 2015) Arkış, Esen; Arkış, Esen; Balköse, Devrim; Balköse, Devrim; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology[No abstract available]Book Part Citation - WoS: 1Preparation, Characterization, and Applications of Magnesium Stearate, Cobalt Stearate, and Copper Stearate(Taylor and Francis Ltd., 2014) Gönen, Mehmet; İnal, Fikret; Egbuchunam, Theresa O.; Balköse, Devrim; Balköse, Devrim; Ülkü, Semra; İnal, Fikret; Ülkü, Semra; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology[No abstract available]Article Citation - WoS: 17Citation - Scopus: 19Effect of Operational Conditions on Separation of Lithium From Geothermal Water by ?-Mno2 Using Ion Exchange–membrane Filtration Hybrid Process(Taylor and Francis Ltd., 2018) Recepoğlu, Yaşar Kemal; Recepoğlu, Yaşar Kemal; Kabay, Nalan; Yoshizuka, Kazuharu; Nishihama, Syouhei; Yılmaz İpek, İdil; Arda, Müşerref; Yüksel, Mithat; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyA hybrid system coupling ion exchange and ultrafiltration (UF) was employed to separate lithium from lithium-spiked geothermal water. The effect of process parameters such as adsorbent type, adsorbent dosage, permeate flow rate, and replacement speeds of fresh and saturated adsorbents have been evaluated to determine the efficiency of the hybrid system. According to the results obtained using λ-MnO2 derived from spinel-type lithium manganese dioxide, the optimal operating conditions to separate lithium from geothermal water were found with powdery λ-MnO2 with an adsorbent concentration of 1.5 g adsorbent/L solution, replacement rates of fresh and saturated adsorbents of 6.0 mL/min, and a permeate flow rate of 5.0 mL/min. The ion exchange–UF hybrid system providing an advantage to work with very fine particles easily can be considered as a favorable process for the separation of lithium from geothermal water.Article Analyzing the Surface Properties of Acrylic-Based Water-Soluble Polymers(Taylor and Francis Ltd., 2017) Topaloğlu Yazıcı, Demet; Çetinkaya, Hayrullah; Şölener, Musa; Albayrak, Adile; 01. Izmir Institute of TechnologyThe surface properties of newly synthesized N-methoxy isopropyl acrylamide, N-methoxy isopropyl methacrylamide, cyclo propyl acrylamide, and cyclo propyl methacrylamide polymers were investigated using inverse gas chromatography. The highest dispersive component of the surface energy value was obtained for cyclo propyl methacrylamide at 30°C. The values obtained for all polymers were decreasing with the increasing temperature. The values obtained for the acidic and the basic parameters revealed strong basic characters for the surface of N-methoxy isopropyl methacrylamide and cyclo propyl methacrylamide polymers and weak basic characters for the surface of N-methoxy isopropyl acrylamide and cyclo propyl acrylamide polymers.Article Citation - WoS: 2Citation - Scopus: 2Morphology of Sodium Salt of Calf Thymus Dna on Mica, Alumina, and Silica Surfaces: Effect of Solvent and Drying Method(Taylor and Francis Ltd., 2017) Yetgin, Senem; Balköse, Devrim; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyInvestigation of morphology of deoxyribonucleotide triphosphate (DNA) dried on different surfaces by atomic force microscopy (AFM) is important in DNA research that is focused on subjects of condensation for gene therapy, sizing, DNA mapping, and cancer examination. The solvent, the surface type, and the method of drying effect the morphology of DNA on solid surfaces. Ethanol and water were used as solvents, flat mica, silica, and alumina surfaces were used as the substrates in the present study. Different methods such as ambient air-drying, N2-forced flow regime drying, and freeze-drying have been applied to droplets of DNA solutions in water or ethanol on the substrates. Forced flow drying regime causes nonlinear DNA attachment on the surface and self-assembly. DNA vertical distance on mica surface was found to be 6 and 1.4 nm for DNA dried in ambient air from ethanol and water solutions, respectively. It was 1.6 nm for N2 flow drying of aqueous DNA solution on mica surface. It was 4.6, 4.6, and 1.99 nm for ambient, N2 flow, and freeze-dried aqueous DNA on alumina surfaces, respectively. Aqueous solution of DNA dried under N2 flow on silica surface had 0.8 nm vertical distance. The smallest standard deviation of 0.05 nm was observed for DNA dried under N2 flow on alumina surface.Article Citation - WoS: 2Citation - Scopus: 3Evaluation of Boron Industrial Solid Waste in Composite Materials(Taylor and Francis Ltd., 2018) Topaloğlu Yazıcı, Demet; Çetinkaya, Hayrullah; 01. Izmir Institute of TechnologyBoron industrial solid waste is used as reinforcement for preparing composite materials. This waste has boron trioxide which holds unique properties may affect the surface or interface of the composite. The prepared composites are characterized in order to determine the dispersion and the structure by means of inverse gas chromatography (IGC), Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy (SEM) and X-ray diffraction (XRD). There is a strong relation between the dispersion of reinforcement and the properties of newly formed composite. The dispersive component of the surface energies of the composites and components are determined by IGC. This parameter is difficult to measure by other methods and it is related to the wettability and adhesive characters of solid materials. The effect of compounding ratios of reinforcement is also examined. Furthermore, XRD diffractograms and SEM images of composites showed well dispersion. Thermal analysis revealed that the addition of the boron industrial solid waste to the polymer increased the thermal stability of pure polymer. Infrared spectra of the composites indicated that the composites were formed from the waste reinforcement and the polymer matrix.Article Citation - WoS: 12Citation - Scopus: 15Assessment and Improvement of Indoor Environmental Quality in a Primary School(Taylor and Francis Ltd., 2017) Ekren, Orhan; Karadeniz, Ziya Haktan; Karadeniz, Ziya Haktan; Toksoy, Macit; Sofuoğlu, Sait Cemil; Toksoy, Macit; 03.07. Department of Environmental Engineering; 03.06. Department of Energy Systems Engineering; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis study reports levels of indoor environmental quality variables before and after installation of heat recovery ventilation in a primary school located in an urban area in Izmir, Turkey. A CO2-based modeling was performed to determine the required flow rates that would comply with an international ventilation standard, followed by computational fluid dynamics modeling for best airflow distribution in a classroom. Temperature, CO2, PM2.5, and total volatile organic compounds were found at undesired levels, among which relative humidity, CO2, and PM2.5 were improved after the intervention. Reductions in the mean and maximum concentrations were 29% and 68% for CO2 and 29% and 46% for PM2.5. This intervention study was a part of the city-wide main project that aimed to increase awareness of the students and their families, teachers, and staff regarding importance of indoor environmental quality in both at school and home due to its possible effects on children's health and academic performance, one of the major challenges of today's societies all around the globe.Article Citation - WoS: 6Citation - Scopus: 8Dehydration, Water Vapor Adsorption and Desorption Behavior of Zn[b3o3(oh)5] · H2o and Zn[b3o4(oh)3](Taylor and Francis Ltd., 2012) Alp, Burcu; Alp, Burcu; Gönen, Mehmet; Balköse, Devrim; Atakul Savrık, Sevdiye; Ülkü, Semra; Balköse, Devrim; Ülkü, Semra; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe dehydration behaviors of two different hydrated zinc borate species, Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3], which are industrially important flame retardants, were studied by thermal gravimetric(TG) analysis and in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Dehydration onset temperatures of Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3] were 129 and 320°C, respectively, at a 10°C/min ramp rate. A very small amount of boric acid was volatilized in addition to water vapor when both samples were heated at 250°C. A significant amount of water vapor was adsorbed by Zn[B3O3(OH)5] · H2O from air at 25°C. However, Zn[B3O4(OH)3] adsorbed a very small amount of water under the same conditions. Both zinc borates did not have a tendency to cake during storage.
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