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Öğe PID controller design for controlling integrating processes with dead time using generalized stability boundary locus(IFAC Secretariat, 2018) Atiç, Serdal; Çökmez, Erdal; Peker, Fuat; Kaya, İbrahimThis paper proposes a method so that all PID controller tuning parameters, which are satisfying stability of any integrating time delay processes, can be calculated by forming the stability boundary loci. Processes having a higher order transfer function must first be modeled by an integrating plus first order plus dead time (IFOPDT) transfer function in order to apply the method. Later, IFOPDT process transfer function and the controller transfer function are converted to normalized forms to obtain the stability boundary locus in (KKcT, KKc(T2 / Ti)), (KKcT, KKcTd) and (KKc(T2/Ti), KKcTd) planes for PID controller design. PID controller parameter values achieving stability of the control system can be determined by the obtained stability boundary loci. The advantage of the method given in this study compared with previous studies in this subject is to remove the need of re-plotting the stability boundary locus as the process transfer function changes. That is, the approach results in somehow generalized stability boundary loci for integrating plus time delay processes under a PID controller. Application of the method has been clarified with examples.Öğe An analysis of sport managers' work stress levels in various variables(Horizon Research Publishing, 2018-12) Kılınç, Zühal; Dinçer, NevzatThis paper was conducted to measure the psychological and psychosomatic symptoms related with the sport managers’ work stress in public sector and federations. In this research, total 185 sport managers including 31 sport managers from the Central Organization of Sport General Directorate, 113 sport managers from the provincial organization, 41 sport managers from the Independent Sport Federations were included. The relevant managers were applied the work stress scale developed by Houso and Rizzo (1972). According to the results of the research, as sport managers get older, the averages of work stress seem to increase. In younger sport managers, the averages of work stress were found to be lower. When the participant sport managers’ education levels improve, their work stress points fall down. In the first period of service of sport managers, the averages of work stress were high, in next years they went down over time.Öğe Performance and exhaust emissions of a DI diesel engine fueled with waste cooking oil and inedible animal tallow methyl esters(TÜBİTAK, 2011) Altun, ŞehmusThe performance and exhaust emissions of a direct injection diesel engine were experimentally investigated using 2 biodiesel fuels with promising economic perspective, one obtained from inedible animal tallow and the other from waste cooking oils. Inedible animal tallow, which is obtained from a mixture of slaughtered cattle and sheep fats collected from a local slaughterhouse during meat preparation process, was transesterified using methyl alcohol and an alkaline catalyst to produce the inedible animal tallow methyl ester. Biodiesel from waste cooking oil was produced from waste cooking oils and methyl alcohol via a transesterification reaction, and provided by a commercial biodiesel producer. In order to investigate the performance and exhaust emissions, the experiments were conducted at different engine speeds under the full load condition of the engine. The experimental results showed, compared with diesel fuel, that the biodiesel fuels resulted in a reduction in brake torque and in an increase in brake specific fuel consumption. Although both biodiesels caused reductions in carbon monoxide (CO), the NOx emissions were higher for waste cooking oil biodiesel and lower for inedible animal tallow biodiesel as compared to diesel fuel.Öğe Investigation of the usability of biodiesel obtained from residual frying oil in a diesel engine with thermal barrier coating(Journals & Books, 2015-04-05) Aydın, Hüseyin; Sayın, Cenk; Aydın, SelmanIn this study, biofuel was produced from residual frying oil of cottonseed and D2, B5 and B100 fuels were prepared in order to use in experiments. These fuels were tested in a single cylinder, four strokes, 3 LD 510 model Lombardini CI engine. Then the top surfaces of the piston and valves were coated with plasma spray coating method by using 100 μm of NiCrAl as lining layer and over this layer the same surfaces were coated with 400 μm of the mixture that consists of %88 ZrO2, %4 MgO and %8 Al2O3. After the coating process, above mentioned fuels were tested in the coated engine. Previously, same fuels had been tested in uncoated engine, at full load and various speeds. Performance, emission and combustion experiments were carried out in coated engine. By coating process, partial increases were observed in power, exhaust manifold temperature and engine noise, while partial decreases were seen in brake specific fuel consumption (Bsfc). Besides, partial reductions were found in carbon monoxide (CO), hydrocarbon (HC) and smoke opacity emissions, but partial increases were observed in nitrogen oxide (NOx) emissions. Cylinder gas pressure values were higher for coated engine. Moreover, heat releases were close to each other in both engines.Öğe Performance and emission evaluation of a CI engine fueled with preheated raw rapeseed oil (RRO)–diesel blends(Journals & Books, 2010-03) Aydın, Hüseyin; Hanbey, HazarMany studies are still being carried out to find out surplus information about how vegetable based oils can efficiently be used in compression ignition engines. Raw rapeseed oil (RRO) was used as blended with diesel fuel (DF) by 50% oil–50% diesel fuel in volume (O50) also as blended with diesel fuel by 20% oil–80% diesel fuel in volume (O20). The test fuels were used in a single cylinder, four stroke, naturally aspirated, direct injection compression ignition engine. The effects of fuel preheating to 100 °C on the engine performance and emission characteristics of a CI engine fueled with rapeseed oil diesel blends were clarified. Results showed that preheating of RRO was lowered RRO’s viscosity and provided smooth fuel flow Heating is necessary for smooth flow and to avoid fuel filter clogging. It can be achieved by heating RRO to 100 °C. It can also be concluded that preheating of the fuel have some positive effects on engine performance and emissions when operating with vegetable oil.Öğe Dimension and insulation thickness optimization of circular flat plate solar collectors(Energy Education Science and Technology, 2011) Argunhan, ZekiIn this study, expressions for optimum radius of a circular flat plate solar collector and the optimum insulation thickness distribution are derived by using the concept of solar gain, which maximizes the life-cycle savings. For the specified condition the optimum radius has been found as 2.14 m and the optimum insulation thickness distribution on back of collectors has been formulized. The insulation material thickness distribution has been determined by performing a detailed dimensional analysis; therefore heat loss is minimized, and results are presented in graphics.Öğe The effects of injection pressure on the engine performance characteristics of a CI engine fueled with canola oil-diesel blends(Energy Education Science and Technology Part A: Energy Science and Research, 2012-01) Aydın, HüseyinThe usage of vegetable oils in diesel engines has some negative effects especially on engine performance. Therefore vegetable oils can not be used as pure form or with high percentages in diesel fuel in unmodified diesel engines. Some of the engine operation conditions should be improved by modifying engine operation systems for this purpose. The effects of injection pressure on engine performance of a diesel engine, by using two different blends of vegetable oil (canola oil) in diesel fuel (DF) having a concentration of 20% (O20) and 50% (O50) vegetable oil, were studied in the present work. The injection pressure was changed from 200 MPa to 220 MPa. Tests were made at fully loaded engine and different speeds of engine operation. In the experiments, the engine power, torque, brake specific fuel consumption (Bsfc), mass fuel consumption rate, brake thermal efficiency and exhaust gas temperature of the test engine have been investigated. Results revealed that the increased injection pressure can significantly promote performance parameters of diesel engine with using vegetable oil without any modification either in oil or in engine itself. The improved results of experiments have been given as graphics in this paper.Öğe Determination of performance and exhaust emissions properties of B75 in a CI engine application(Journals & Books, 2011-09) Aydın, Hüseyin; İlkılıç, CumaliIn this study, performance and exhaust emissions of biodiesel in a compression ignition engine was experimentally investigated. Therefore, biodiesel has been made by transesterification from cotton seed oil and then it was mixed with diesel fuel by 25% volumetrically, called here as B75 fuel. B75 fuel was tested, as alternative fuel, in a single cylinder, four strokes, and air-cooled diesel engine. The effect of B75 and diesel fuels on the engine power, engine torque and break specific fuel consumption were clarified by the performance tests. The influences of B75 fuel on CO, HC, NOx, Smoke opacity, CO2, and O2 emissions were investigated by emission tests. The engine torque and power, for B75 fuel, were lower than that of diesel fuel in range of 2–3%. However, for the B75, specific fuel consumption was higher than that of diesel fuel by approximately 3%. CO2, CO, HC, smoke opacity and NOx emissions of B75 fuel were lower than that of diesel fuel. The experimental results showed that B75 fuel can be substituted for the diesel fuel without any modifications in diesel engines.Öğe Mechanical properties of fiber/graphene epoxy hybrid composites(SpringerLink, 2020-11-18) Çelik, Yahya Hışman; Topkaya, Tolga; Kılıçkap, ErolThe aim of this study is to determine the effect of graphene nanoparticle (GNP) reinforcement on the mechanical properties of glass fiber reinforced polymer (GFRP), carbon fiber reinforced polymer (CFRP) and aramid fiber reinforced polymer (AFRP) composites commonly used in the space and defense industry. Accordingly, GFRP, CFRP and AFRP composites were produced by using hot pressing method. In addition, hybrid fiber composites were produced by adding 0.1 %, 0.2 % and 0.3 % GNP to these fiber reinforced composites. The tensile strength and modulus of elasticity of the composites were determined. The tensile damage fracture regions were analyzed by scanning electron microscopy (SEM) and energy distribution spectrum (EDS). It was observed that the addition of 0.2 wt. % GNP to GFRP and CFRP composites increased tensile strength and modulus of elasticity. However, the addition of 0.2 wt. % GNP to AFRP composites had no effect on the tensile strength; on the contrary, it partially reduced the tensile strength but increased the modulus of elasticity. On the fracture damage surfaces of the GFRP and CFRP composites and the GNP/GFRP and GNP/CFRP hybrid composites, the fibers were completely separated. On the damage surfaces of AFRP composite and GNP/AFRP hybrid composites, the fibers were deformed but these fibers were not separated from each other. From the EDS analysis, it was observed that the element C increased in the composites with the addition of GNP to the fiber reinforced compositesÖğe Diesel engine applications for evaluation of performance and emission behavior of biodiesel from different oil stocks(Environmental Progress & Sustainable Energy, 2015-05) Aydın, Hüseyin; Behçet, Rasim; İlkılıç, Cumali; İşcan, Bahattin; Aydın, SelmanExtensive researches on alternative fuels have been carried out since the fossil-based fuels are limited. Many of these studies have ever been on the usability of vegetable oils in diesel engines. In the current work, biodiesel were produced from waste fish oil (FOB), hazelnut oil (HOB), rapeseed oil (ROB), and waste cooking oil (WCOB) by transesterification method. The same optimized variables of 6:1 methanol/oil molar ratio (mol/mol), 0.4% sodium methoxide concentration (wt.%), 60°C reaction temperature, 1000 rpm agitation speed and 2 h reaction time conditions were performed for biodiesel production from all kinds of above mentioned oils. Some of the important chemical and physical properties of test fuels were found. Without making blends with diesel fuel, pure biodiesels were used in a diesel engine in order to clarify how their usage effects on engine performance and exhaust emission parameters. When compared with those of diesel fuel, average torque and power were reduced while brake specific fuel consumption was increased for biodiesels. Besides, carbon monoxide (CO), hydrocarbon (HC) emissions were considerably lower for biodiesel usage while oxides of nitrogen (NOx) emissions were higher than that of diesel fuel. Furthermore, emissions of carbon dioxide (CO2) and smoke opacity were reduced for biodiesel usage. Oxygen (O2) contained in the exhaust gases were higher for biodiesels while they contain more oxygen molecules in their structure
