Yazar "Cay, Yusuf" seçeneğine göre listele
Listeleniyor 1 - 14 / 14
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe The Change of Air Pollution in Karabuk with the Usage of Natural Gas(Karabuk Univ, 2012) Yildiz, Abdulaziz; Cay, Yusuf; Ozer, FirdevsThe Usage of fossil origin fuels is one of the most important cause of air pollution. The usage of these fuels unconsciously causes environmental problems especially air pollution. In this study air pollution parameters (SO2 ve PM10) were analyzed before and after the usage of natural gas in Karabuk. The effect of usage natural gas on air quality is researched. In this city before 2010 coal, foul-oil and diesel were used to provide heat demanded then it is started using natural gas by 2010. With starting the usage of natural gas, the usage of these kind of fuels (coal, foul-oil, and diesel) has been decreased. At the end of the study-in the Air Quality Assessment and Management Regulation (AQAMR)-it is concluded that the value of 250 mu g/m(3) for SO2 is over in some months before using natural gas but it hasn't exceeded 250 mu g/m(3) after starting the usage of natural gas. It has been identified that the value of 200 mu g/m(3) which is specified in regulations for PM10 has been exceeded and reached to 267 mu g/m(3) in the winter season. It has been observed that with starting the usage of natural gas, this value is again decreased in 2010. It is observed that while the usage of natural gas is getting more and more the value of SO2 ve PM10 are significantly decreased.Öğe Determination of optimum insulation thickness, energy savings, and environmental impact for different climatic regions of Turkey(Wiley-Blackwell, 2013) Cay, Yusuf; Gurel, Ali EtemIn this study, optimum insulation thicknesses, energy savings, and payback periods have been investigated based on life-cycle cost analysis for an external wall in four various cities from four climate zones of Turkey. Also, the study have been analyzed the effect of insulation thickness on release of CO2 and SO2 emissions. The results show that insulation thicknesses vary between 0.045 and 0.195 m, life-cycle energy savings between 13.26 and 248.9 $/m2, payback periods between 1.19 and 1.97 years when used extruded polystyrene as insulation material. When the optimum insulation thickness was used, emissions were reduced by 6292% depending on the city, fuel type, and insulation material. (c) 2012 American Institute of Chemical Engineers Environ Prog, 32: 365-372, 2013Öğe Dynamic analysis of gun barrel vibrations due to effect of an unbalanced projectile considering 2-D transverse displacements of barrel tip using a 3-D element technique(Latin Amer J Solids Structures, 2018) Koc, Mehmet Akif; Esen, Ismail; Cay, YusufIn this paper, dynamic analysis of two different weapon systems (35 mm Anti-Aircraft Barrel (AAB) and 120 mm Grooved Tank Barrel (GTB)) under the effect of statically unbalanced projectile has been performed with a new 12 DOF 3-D element technique using Finite Element Method (FEM). The muzzle deviations, which negatively affect the barrel shooting accuracy at firing, are calculated in a time dependent manner using Newmark beta algorithm with high accuracy at both axes (yand z) considering the Coriolis centripedal and centrifugal forces. The effect of such fundamental physical parameters as shift from rotating center and angular velocity belonging to the unbalanced projectile on barrel dynamics are analyzed with this new and affective FEM. As a result, it was found out that 1% of a millimeter shift from projectile belonging to a weapon system leads to excessive vibration on both axes and compromises the shooting accuracy of the barrel.Öğe The Effect of External Wall Optimum Insulation Thickness on Energy Saving and Air Pollution For karabk(Karabuk Univ, 2012) Gurel, Ali Etem; Cay, Yusuf; Dasdemir, Ali; Kucukkulahli, EnverHeat insulation applications carried out on external walls of building provides energy saving by decreasing fuel consumption and also quite important in decreasing emission which results from fossil-based fuel usage and causes air pollution. In this study, economic and environmental analyses were done for determination of external wall optimum thickness in using coal and natural gas usage in Karabuk. Economic extent of the study was done with P-1-P-2 method which is based on life cycle cost analysis (LCCA). The results show that optimum insulation thickness and energy saving are 0.134 m and 117.14 TL/m(2) respectively when coal is used as a fuel. These values are 0.116 m and 88.39 TL/m(2) when natural gas is used as fuel. When the effects of optimum insulation thickness on air pollution are observed, CO2 and SO2 emissions calculated on external wall of uninsulated building decreased up to 85.4% at the point of optimum insulation thickness according to fuel type.Öğe Energy Saving and Emission Reduction Opportunities in Mixed-Fueled Industrial Boilers(Wiley-Blackwell, 2014) Kaya, Durmus; Eyidogan, Muharrem; Kilic, Fatma Canka; Cay, Yusuf; Cagman, Selman; Coban, VolkanIn this article, an energy efficiency study has been performed in an industrial establishment. The boiler of this industrial establishment is a mixed-fueled (solid+gas) type and operated with different fuels as coal, coke gas, and blast furnace gas, the pressure of 7000 kPa (70 bars) and temperature of 778.15 K (505 degrees C) and with a nominal capacity of 27.77 kg/s (100.000 kg/h) steam. In this context, the working temperature, pressure, velocity, and combustion gas measurements have been carried out at the boiler operation conditions. Using with all these measurements, the energy and mass balance equations have been set and the boiler efficiency has been calculated as the value of 85.91%. The main efficiency losses have been determined as: operating the boiler at the high air excessiveness coefficient, the air leakage in the rotary type air heaters and the heat losses of the surface. Total energy savings potential is 2,029,692 kcal/h. When anticipated enhancements can be carried out, the boiler efficiency will be 88.94%. In this case, 4861.7 tons of carbon dioxide emissions per year will be reduced. (c) 2014 American Institute of Chemical Engineers Environ Prog, 33: 1350-1356, 2014Öğe Finite element formulation and analysis of a functionally graded Timoshenko beam subjected to an accelerating mass including inertial effects of the mass(Latin Amer J Solids Structures, 2018) Esen, Ismail; Koc, Mehmet Akif; Cay, YusufThis study describes a new finite element method that can be used to analyse transverse and axial vibrations of a Functionally Graded Material (FGM) beam under an accelerating / decelerating mass. The differential equations of the FGM beam are obtained using First-order Shear Deformation Theory (FSDT). In these equations, the interaction terms of mass inertia are derived from the second-order exact differentiation of displacement functions with respect to mass contact point. The FGM beam is made of two different materials (Steel and Alumina Al2O3), which vary in thickness with a power law. Including the effects of neutral axis shift and mass inertia, the proposed method can be used when the dynamic behaviour of the FGM Timoshenko beams is to be analysed in transverse and axial directions, depending on the interaction with the acceleration of the moving loads. After validating this work with literature studies, new investigations and fmdings are presented for both moving load and mass assumptions. In addition, the obtained results of Timoshenko Beam (TBT) and Euler Bernoulli beam theory (EBT) are compared for FGM beams with various speeds and accelerations of moving mass.Öğe The impact of determination of optimum insulation thickness on energy saving for different climatic regions of Turkey(Sila Science, 2011) Cay, YusufMost of the energy resources are used for heating purposes in Turkey. For this reason significant energy can be saved by insulation applications on buildings. However, if the thickness of the chosen insulation material is above optimum thickness, additional costs will incur. In this paper the optimum insulation thicknesses, energy saving and payback periods for four provinces chosen from different climatic regions of Turkey have been calculated. Optimization calculation was made according to life-cycle cost (LCC) analysis. As a result of the calculations made based on five different fuel types (coal, natural gas, fuel-oil, LPG and electricity) and four different insulation materials (rock wool, extruded polystyrene, expanded polystyrene, foamed polyurethane), it was seen that energy saving was 21% and 80.18% and payback period was between 1.247 and 4.6 years at the optimum insulation thicknesses of 0.02 m and 0.202 m.Öğe The impact of methanol fuelled spark ignition engines on engine performance and exhaust emissions(Sila Science, 2011) Korkmaz, Ibrahim; Cay, YusufIn this study, the performance and exhaust emission values of engine have been investigated according to the results obtained from the experimental study using gasoline and methanol fuels in spark ignition engines. In these experiments a regular automobile engine with 4 cylinders, 4 strokes and 1,3 liter volume was used. Without making any modifications on the engine, the engine performance has been determined for both fuels between the ranges of 1100-4000 rpm, 5-40 Nm torque values. In the experimental study, the rotation number, torque, strength, mean effective pressure, brake specific fuel consumption, fuel flow rate, exhaust temperature and exhaust emission values of the engine have been measured. According to the experiment results, if the engine works on gasoline, its minimum brake specific fuel consumption becomes 400 g/kWh, whereas if it works on methanol this value becomes 900 g/kW. The values of CO emission of the engine vary between 2 and 6% for gasoline, whereas the range for methanol is between 1 and 4%. Minimum HC emission values, on the other hand, have been observed as 330 ppm for gasoline and 250 ppm for methanol.Öğe Modelling of Thrust Forces in Drilling of AISI 316 Stainless Steel Using Artificial Neural Network and Multiple Regression Analysis(Assoc Mechanical Engineers Technicians Slovenia, 2012) Cicek, Adem; Kivak, Turgay; Samtas, Gurcan; Cay, YusufIn this study, the effects of cutting parameters (i.e., cutting speed, feed rate) and deep cryogenic treatment on thrust force (Ff) have been investigated in the drilling of AISI 316 stainless steel. To observe the effects of deep cryogenic treatment on thrust forces, M35 HSS twist drills were cryogenically treated at -196 degrees C for 24 h and tempered at 200 degrees C for 2 h after conventional heat treatment. The experimental results showed that the lowest thrust forces were measured with the cryogenically treated and tempered drills. In addition, artificial neural networks (ANNs) and multiple regression analysis were used to model the thrust force. The scaled conjugate gradient (SCG) learning algorithm with the logistic sigmoid transfer function was used to train and test the ANNs. The ANN results showed that the SCG learning algorithm with five neurons in the hidden layer produced the coefficient of determinations (R-2) of 0.999907 and 0.999871 for the training and testing data, respectively. In addition, the root mean square error (RMSE) was 0.00769 and 0.009066, and the mean error percentage (MEP) was 0.725947 and 0.930127 for the training and testing data, respectively.Öğe A new numerical method for analysing the interaction of a bridge structure and travelling cars due to multiple high-speed trains(Inderscience Enterprises Ltd, 2021) Koc, Mehmet Akif; Esen, Ismail; Eroglu, Mustafa; Cay, YusufDynamic interaction between a 10-DOF high-speed train model and a simply supported bridge beam is studied. The second-order coupled equations of the bridge beam and train are derived using Lagrange method. The proposed method in the study provides considerable advantage by taking 0.5% of the time needed in analysing the train-bridge interaction (TBI) previously given in the literature using the finite element method (FEM). The presented modelling that includes the dynamic forces on the train components from the interaction, is created in a manner that it may assist both train and bridge engineers. It is showed that, while moving on the bridge, the dynamic forces on the train body, front and rear bogies, wheels as well as bridge are significantly affected by the speed and mass of the train, along with the flexibility of the bridge. Effects of multiple cars are included in the modelling.Öğe Prediction of a gasoline engine performance with artificial neural network(Elsevier Sci Ltd, 2013) Cay, YusufThis study deals with artificial neural network (ANN) modeling of a gasoline engine to predict the brake specific fuel consumption, effective power and exhaust temperature of the engine. To acquire data for training and testing the proposed ANN, a four-cylinder, four-stroke test engine was fuelled with gasoline having operated at different engine speeds and torques. Using some of the experimental data for training, an ANN model based on standard back-propagation algorithm for the engine was developed. Then, the performance of the ANN predictions were measured by comparing the predictions with the experimental results. Engine speed, engine torque, fuel flow rate, intake manifold mean temperature and cooling water inlet temperature have been used as the input layer, while brake specific fuel consumption, effective power and exhaust temperature have also been used separately as the output layer. It is shown that R-2 values are about 0.99 for the training and test data; RMS values are smaller than 0.02; and MEP are smaller than 2.7% for the test data. This study shows that, as an alternative to classical modeling techniques, the ANN approach can be used to accurately predict the performance, temperature and other parameters of internal combustion engines. (C) 2012 Elsevier Ltd. All rights reserved.Öğe Prediction of engine performance and exhaust emissions for gasoline and methanol using artificial neural network(Pergamon-Elsevier Science Ltd, 2013) Cay, Yusuf; Korkmaz, Ibrahim; Cicek, Adem; Kara, FuatThis study investigates the use of ANN (artificial neural networks) modelling to predict BSFC (break specific fuel consumption), exhaust emissions that are CO (carbon monoxide) and HC (unburned hydrocarbon), and AFR (air-fuel ratio) of a spark ignition engine which operates with methanol and gasoline. To obtain training and testing data, a number of experiments were performed with a four-cylinder, four-stroke test engine operated at different engine speeds and torques. The experimental results reveal that the methanol improved the emission characteristics compared with the gasoline. For the ANN modelling, the standard back-propagation algorithm was found to be the optimum choice for training the model. In the building of the network structure, four different learning algorithms were used such as BFGS (Quasi-Newton back propagation), LM (Levenberg-Marquardt learning algorithm). It was found that the ANN model is able to predict the engine performance and exhaust emissions with a correlation coefficient of 0.998621, 0.977654, 0.998382 and 0.996075 for the BSFC, CO, HC and AFR for testing data, respectively. It was obvious that the developed ANN model is fairly powerful for predicting the brake specific fuel consumption and exhaust emissions of internal combustion engines. (C) 2012 Elsevier Ltd. All rights reserved.Öğe A Research for Heating Energy Values in Karabuk Province(Karabuk Univ, 2012) Erturk, Mustafa; Coskum, Can; Cay, Yusuf; Kocyigit, Alevay; Oktay, ZuhalIn this study, the data set of the past 32 years obtained from Turkish State Meteorological Services was used. With this data set, heating degree-hour values of Karabuk province were estimated according to eleven different indoor reference temperatures (18-28 degrees C). The increase or the decrease in energy demand was estimated proportionally depending on the condition that the indoor reference temperature, which was selected based on the heating degree-hour values of Karabuk province, is above or below the range of 1-11 degrees C. This study indicates that minor arrangements to be made pertaining to the indoor temperature without disturbing the comfort of the environment will make a significant contribution to reduce the global warming originating from environmental-air pollution as well as the energy dependency of our country.Öğe Tip Deflection Determination of a Barrel for the Effect of an Accelerating Projectile Before Firing Using Finite Element and Artificial Neural Network Combined Algorithm(Latin Amer J Solids Structures, 2016) Koc, Mehmet Akif; Esen, Ismail; Cay, YusufFor realistic applications, design and control engineers have limited modelling options in dealing with some vibration problems that hold many nonlinearity such as non-uniform geometry, variable velocity loadings, indefinite damping cases, etc. For these reasons numerous time consuming experimental studies at high costs must be done for determining the actual behaviour such nonlinear systems. However, using advantages of multiple computational methods like Finite Element Method (FEM) together with an Artificial Intelligence (ANN), many complicated engineering problems can be handled and solved to some extent. This study, proposes a new collective method to deal with the nonlinear vibrations of the barrels in order to fulfil accurate shooting expectancy. Using known analytical methods, in practical, to determine dynamic behaviour of the barrel beam is not possible for all conditions of firing that include numerous varieties of ammunition for different purposes, and each projectile of different ammunition has different mass and exit velocity. In order to cover all cases this study proposes a new method that combines a precise FEM with ANN, and can be used for determining the exact dynamic behaviour of a barrel for some cases and then for precisely predicting the behaviour for all other possible cases of firing. In this study, the whole nonlinear behaviour of an antiaircraft barrel were obtained with 3.5% accuracy errors by ANN trained by FEM using calculated analysis results of ammunitions for a particular range. The proposed FEM-ANN combined method can be very useful for design and control engineers in design and control of barrels in order to compensate the effect of nonlinear vibrations of a barrel for achieving a higher shooting accuracy; and can reduce high-cost experimental works.
