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Öğe Archaeozoological study of a unique Late Neolithic pitfrom Tepecik-Çiftlik, central Turkey(Anthropozoologica, 2019-08-16) Gündem, Can YumniThe absence of written evidence from prehistoric periods makes it difficult to understand the origins of sacrifice or offering ceremonies. Archaeological finds from prehistoric periods are the only solid evidence for these acts and rituals. One probable case of animal sacrifice or offering in the Neolithic period has been found at the site of Tepecik-Çiftlik Höyük in central Turkey. This study is focused on a single unique pit, which contained only animal bones and was found in an open space. The contents clearly indicate that this pit can not be interpreted simply as mixed kitchen garbage since an almost complete cattle skeleton as well as sixteen left front leg remains from sheep were placed in the pit after a social, or more specifically, ritual act. Similar pit with similar content was found neither in the close region to Tepecik-Çiftlik nor within Anatolia. The main aim of this study is to introduce a special archaeological find group, those were left after certain prehistoric activity.Öğe A generalization of the Katzman-Zhang algorithm(Elsevier, 2021-03) Yeşil, MehmetIn this paper, we study the notion of special ideals. We generalize the results on those as well as the algorithm obtained for finite dimensional power series rings by Mordechai Katzman and Wenliang Zhang to finite dimensional polynomial rings.Öğe Analysis of interface states of Al/DNA/p-Si MIS photovoltaic structures with DNA biomolecules using the conductance technique(Taylor & Francis, 2017-03-29) Güllü, ÖmerIn this study, we report on the calculation of interface charge distribution of metal–interlayer–semiconductor (MIS) photovoltaic diodes containing DNA biomolecules and Si semiconductor based on the conductance technique. DNA biofilms were deposited at room temperature using a simple cast method on p-type Si. Interface parameters of the Al/DNA/p-Si structures were investigated by using capacitance–voltage (C–V) and conductance–voltage (G–V) measurements as a function of frequency. The distributions of interfacial charge states and the trap relaxation times were reported. Also, photoelectric and photocapacitance properties of the diode were measured at room temperature.Öğe An artificial neural network model to predict the thermal properties of concrete using different neurons and activation functions(Hindawi, 2019-04-01) Fidan, Şehmus; Oktay, Hasan; Polat, Süleyman; Öztürk, SarperGrowing concerns on energy consumption of buildings by heating and cooling applications have led to a demand for improved insulating performances of building materials. The establishment of thermal property for a building structure is the key performance indicator for energy efficiency, whereas high accuracy and precision tests are required for its determination which increases time and experimental costs. The main scope of this study is to develop a model based on artificial neural network (ANN) in order to predict the thermal properties of concrete through its mechanical characteristics. Initially, different concrete samples were prepared, and their both mechanical and thermal properties were tested in accordance with ASTM and EN standards. Then, the Levenberg-Marquardt algorithm was used for training the neural network in the single hidden layer using 5, 10, 15, 20, and 25 neurons, respectively. For each thermal property, various activation functions such as tangent sigmoid functions and triangular basis functions were used to examine the best solution performance. Moreover, a cross-validation technique was used to ensure good generalization and to avoid overtraining. ANN results showed that the best overall R2 performances for the prediction of thermal conductivity, specific heat, and thermal diffusivity were obtained as 0.996, 0.983, and 0.995 for tansig activation functions with 25, 25, and 20 neurons, respectively. The performance results showed that there was a great consistency between the predicted and tested results, demonstrating the feasibility and practicability of the proposed ANN models for predicting the thermal property of a concrete.Öğe Electrooxidation of thiourea and its square-wave voltammetric determination using pencil graphite electrode(Walter de Gruyter, 2011-04-01) Levent, Abdulkadir; Keskin, Ertuğrul; Yardım, Yavuz; Şentürk, ZühreThe electrochemical properties of thiourea (TU) were investigated in pH range 2.0-12.0 by cyclic and square-wave voltammetry. The compound was irreversibly oxidized at a pencil graphite electrode in one or two oxidation steps which are pH-dependent. Based on the voltammetric peak for the second oxidation process of TU in phosphate buffer at pH 12.0, a square-wave voltammetric method was proposed for the determination of the compound in the range 6.3-30μm, with a detection limit of 1.29μm. The applicability to direct assays of wastewaters was also tested.Öğe Emissions from a diesel power generator fuelled with biodiesel and fossil diesel fuels(SAGE Journals, 2015-08-01) Altun, ŞehmusThe aim of this work was to compare the emission characteristics of a biodiesel derived from waste cooking sunflower oil and two fossil diesel fuels (ultra-low sulphur diesel and its type of containing gas-to-liquid). The tests were conducted on a direct-injection diesel engine-powered generator set, which is the type of generator applied in institutional facilities, under variable load and constant engine speed conditions. Experimental results showed that diesel containing gas-to-liquid and biodiesel reduced smoke opacity while NOx emissions were slightly higher for both fuels. An increase in fuel consumption was also observed for biodiesel compared with both fossil diesels. Unburned HC emissions were high for biodiesel, but overall level of CO emissions remained very low for all fuels testedÖğe An investigation of the effect of parameters and chip slenderness ratio on drilling process quality of AISI 1050 steel(Hindawi, 2018-05-08) Demir, Zülküf; Yakut, RıfatThe chip slenderness ratio is a vital parameter in theoretical and applicable machining operations. In predrilled drilling operations of AISI 1050 steel alloy, HSS drills were employed, and the effect of the selected parameters on the chip slenderness ratio and also the effect of the chip slenderness ratio on the thrust force, surface roughness, drilled hole delamination, tool wear, and chip morphology were investigated. The major parameters, influential on the chip slenderness ratio, were feed rate and point angle, while spindle speed was too small to be negligible. With increasing the chip slenderness ratio, the thrust force and the tool wear decreased, which resulted in appropriate chip morphology, but there were increases in surface roughness. However, the chip slenderness ratio had no effect on the drilled hole delamination.
