Göksel Özkan

Application of Box–Wilson Optimization Technique to the Partially Oriented Yarn Properties

A static model for partially oriented yarn (POY) production was examined in a commercial POY spinning plant. A two-level factorial, industrial experimental design was used to identify a statistical model. Three independent variables effecting the elongation at break (a POY property of interest) were selected. Namely, yarn winding speed, spinneret flow rate, and spinneret hole diameter. Elongation at break was chosen as the dependent variable. A first-order statistical model was considered to show the dependence of the elongation at break on the operating parameters: 145%; for elongation at break, the optimum values of yarn winding speed, spinneret flow rate, and spinneret hole diameter were found to be as 2938 m/min, 49.74 g/min, and 205 μm, respectively. The statistical model and Box–Wilson steepest ascent method were used.

Combustion of a high ash and sulfur containing lignite in a pilot circulating fluidized bed combustor and its pollution characteristics

Abstract In this study a 50 kW circulating fluidized bed combustor (low velocity regime CBF combustor) was constructed for the combustion of high ash containing lignites. Beypazarý lignite which contains 45% ash and 3.72% sulfur was mixed with limestone and was burnt in this combustor. Emission characteristics were investigated at different Ca/S mole ratios. It was shown that SO 2 removal efficiencies reached values of 98%. At an average bed temperature of 850°C NO x emission levels were found to be around 300 ppm however CO emissions were around 1466 ppm. Temperature variation along the combustor (of 1.8 m in height) was found to be about 140 and 90°C for two different feed points located at 0.17 and 0.52 m above the distributor and two different feedback points located at 0.37 and 0.17 m above the distributor, respectively.

Synthesıs and Characterızatıon of Molten Carbonate Fuel Cell Anode Materıals

Molten carbonate has high energy potential, which can be used as a source of energy in industrial applications. In this study, the anode of a molten carbonate fuel cell is synthesized and characterized. Three different types of anode materials for molten carbonate are synthesized using tape-casting method. These materials are nickel, nickels–chrome tape including 5% chrome, and nickels–chrome tape including 10% chrome. After that, all anodes were plated with alumina by an impregnation method. Surface areas of these different anodes and their porosities were determined. It was observed that plating with alumina improved the surface areas of molten carbonate fuel cell anodes.

The prediction of SO 2 removal using statistical methods and artificial neural network

Artificial neural network and a statistical model have been applied in a laboratory scale trickle bed reactor (TBR) to investigate the SO2 removal efficiency of activated carbon. The performance of artificial neural network (ANN) model has been compared with the statistical model based on central composite experimental design. Two independent variables, which affect the amount of SO2 removal by the liquid phase in the TBR, were selected; namely liquid flow rate and gas flow rate. Amount of SO2 removal was chosen as the dependent variable (target data). A second order statistical model has been considered to show the dependence of the amount of SO2 removal on the operating parameters. A back-propagation ANN has been used to develop a model relating to the amount of SO2 removal. A series of experiments have been conducted on the basis of the statistics-based design of experimental method. It is observed that a neural network architecture having one input layer with two neurons, one hidden layer with three neurons, one output layer with one neuron and an epoch size of 20 gives better prediction. The predictions are more accurate than those obtained from regression models.

Amonyak boran varlığında gözenekli stiren divinil benzen kopolimer küreciklerin optimum sentez koşullarının belirlenmesi

DOI: Bu çalışmada, önemli endüstriyel polimerlerden stiren divinil benzen (SDVB) kopolimer küreciklerinin gözenekliliğini artırmak amacıyla amonyak boran varlığında sentezi ile optimum sentez koşulları araştırılmıştır. Bu amaç doğrultusunda başlatıcı olarak benzol peroksit, stabilizatör olarak polivinil alkol (PVA) ile sodyum hidroksit (NaOH), organik çözücü olarak ikili toluen-hekzan karışımı kullanılmış ve sentezler süspansiyon polimerizasyonu yöntemiyle yapılmıştır. Amonyak boran (AB) başlatıcı içine farklı miktarlarda karıştırılarak kullanılmıştır. Polimerizasyon tepkimesi azot atmosferinde, 80C sıcaklıkta ve atmosferik basınçta gerçekleştirilmiştir. Parametrik çalışmalar sonucu elde edilen kopolimer küreciklerinin yüzey alanı, gözenekliliği (BET analizleriyle), yapı tayini (Fourier transform infrared spektrometrisi, FTIR ile) ve ıslak faz şişmesi gibi bazı karakteristik özellikleri belirlenmiştir. Sentezlenen kopolimerlerde AB’nin gözenek oluşumuna ve partikül boyut dağılımına katkı sağladığı, DVB yüzdesinin artmasıyla polimerizasyon verimi artarken küreciklerin şişme yüzdesinin azaldığı görülmüştür. Design Expert 8.0.7.1 (deneme sürümü) paket programı altındaki cevap yüzey yöntemi (CYY) kullanılarak merkezi kompozit tasarım yöntemine göre optimum sentez koşullarının %90 DVB; 0,05 g amonyak boran; %200 çözücü miktarında olduğu hesaplanmış ve bu koşullarda sentezlenen kopolimerlerin BET yüzey alanını 156 m/g olarak ölçülmüştür. Asetonla yüzey modifikasyonu sonucu yüzey alanı 274 m/g değerine arttırılmıştır. 10.17341/gazimmfd.300589

The Effect of Temperature and Initial Concentration on Synthesis of Ammonia Borane

In this work, production of ammonium borane (NH3BH3, abbreviated as AB) was studied. In synthesis works, the effect of reaction temperature and reactive inlet material concentrations on the conversion into AB were examined. Synthesis of ammonium borane was obtained from the reaction of NaBH4 and (NH4)2SO4 in THF. As a result of parametrical experiments, it has been determined that product conversion yield is increased from 95.3 to 98.2 % and reaction period is decreased by up to 2 h and product purity value is increased up to 100 % when reaction temperature is increased from 25 to 50 °C. It has been determined that when increased amount of reactive materials is compared with stoichiometric amounts, product conversion increased but limiting agent in the reaction is determined to be NaBH4. According to FTIR, XRD, and 11B NMR analyses results, AB may be synthesized up to purity phase.

Porous metal-organic Cu(II) complex of L-Arginine; synthesis, characterization, hydrogen storage properties and molecular simulation calculations

Cu(II)-arginine coordination compound was synthesized and characterized by using DSC, DTA, EA, FT-IR, XRD, SEM and EDX analysis techniques and then the hydrogen storage properties were investigated. Hydrogen storage performance of synthesized compound was determined both experimental and theoretically by using Materials Studio which is one of the Molecular simulation software and adsorption measurement equipment. It is found out that the arginine compound uptakes approximately 1.2 wt. % experimentally and 0.8 wt. % theoretically hydrogen in 77K and 100 bars pressure. Also the surface characteristics was calculated and also the possible cites which could uptake hydrogen in a single lattice cell were determined. At the end of this research, in addition to drug and other applications of L-arginine, it is proved that could be used as a part of adsorbent for hydrogen storage application. Keywords: Hydrogen Storage; L-Arginine; Coordination Compound; Molecular Simulation DOI: 10.17350/HJSE19030000001 Full Text: Supplementary File: