| 1. | Cover-Contents Pamukkale Üniversitesi Mühendislik Bilimleri Dergisi Pages I - III |
| 2. | COMPARISON OF ENERGY AND EXERGY EFFICIENCIES OF ABSORPTION REFRIGERATION SYSTEM WITH MECHANICAL COMPRESSION REFRIGERATION SYSTEM Gülay YAKAR, Rasim KARABACAK, Burçin DEDA ALTAN Pages 161 - 169 In this study, energy and exergy analysis of absorption refrigeration system using LiBr- water and mechanical compression refrigeration system using R134-a were performed at different evaporation temperatures. The results are presented in tables and figures. |
| 3. | AN APPROACH TO POWER RATIOS AND PROBABILITIES AND INTERPRETATIONS OF THESE QUANTITIES IN RECTANGULAR QUANTUM WELLS Mustafa TEMİZ, Ö. Önder KARAKILINÇ, Adem ÜKTE, Hüsnü ŞENTÜRK Pages 171 - 181 This study focuses on power and probability expressions belong to normalized frequency and normalized propagation constant of electric field in the rectangular quantum well. The confinement effects of the properties of confined carriers in the energy levels have been studied. Normalized frequency and normalized propagation constant are especially functions of the ordinates and abscissas of the energy eigenvalues for electrons or holes in the rectangular quantum well in the normalized coordinate system (?-?). Our calculations also give more accurate results, and present more sensitive comparative examples. |
| 4. | NEW IMPROVED FORMULAS FOR R/C COLUNMS SECTIONS BY ARTIFICIAL NEURAL NETWORKS Ahmet BUDAK, İbrahim CAN Pages 183 - 191 Ultimate strength design of the reinforced concrete (R/C) columns had been investigated and proposed several methods by researchers. Some of these methods are based on to use tables and/or charts while the others are required computer program. Using table or chart is slow and laborious and causes some errors. On the other hand, one must have a computer within reach to use computer program. Our purpose in the present study is to provide simple and reliable formulas for design of rectangular R/C sections subject to axial forces and flexures by artificial neural networks (ANNs). Proposed formulas have been obtained for various steel grades (S220 and S420) and bar arrangements by training ANNs with produced data. |
| 5. | APPLICATION OF THE DIFFERENTIAL QUADRATURE ELEMENT METHOD (DQEM) TO VIBRATION ANALYSIS OF BEAM ELEMENTS Zekeriya GİRGİN, Ersin DEMİR, Cem KOL Pages 193 - 197 The Generalized Differential Quadrature Method (GDQM) is an alternative method direct solution of differential equations on the field of engineering and science. In this study, DQEM which is a new version of GDQM, is presented and applied to vibration analysis of beam elements. In this method, a physical system can be divided into more than one element and no need mass matrix to calculate the natural frequencies of beams. The method has all of the advantages of GDQM and is an effective method with the easy programmability and short computational time. The method considered in details and with the given numerical examples, it is shown that the result are in good agreement with the previous studies. |
| 6. | DESIGNING OF COMPUTER AIDED AND USER INTERACTIVE CNC PART PROGRAMME FOR A MILLING MACHINE M. Ali DÖNERTAŞ, Yılmaz KÜÇÜK, Yakup YILDIZ, İhsan KORKUT Pages 199 - 204 In this study, a user–interactive computer programme generating CNC part programme according to dialog method has been developed. The design of programme has been prepared like a CAM programme structure. The part programme was established by required parameters asking to the user with a specific order. Subsequently, this parameters are used to create M and G codes, and these codes are showed at a different page on the screen. In addition, these code pages can be stored with “txt” format. This program includes basic processes and the programme design has been prepared for milling machine working according to Fanuc system. The computer programme was written by using Delphi 6 programming language. |
| 7. | THE EVALUATION OF EXPERIMENTAL STUDIES ABOUT WEAVABILITY LIMIT Yıldıray TURHAN, Recep EREN Pages 205 - 218 In this paper, some experimental studies about the weavability limits are evaluated. Firstly, fabrics and loom parameters which were considered during these studies are pointed out and then, the results showing how these parameters affect the weavability limits and comparisons with earlier theoretical studies are presented. In conclusion, new experimental studies about the subject are suggested. |
| 8. | EFFECTS OF ETHANOL BLENDED DIESEL FUEL ON EXHAUST EMISSIONS FROM A DIESEL ENGINE Özer CAN, İsmet ÇELİKTEN, Nazım USTA Pages 219 - 224 Diesel engine emissions can be improved by adding organic oxygenated compounds to the No. 2 diesel fuel. In this study, effects of 10 % and 15 % (in volume) ethanol addition to Diesel No. 2 on exhaust emissions from an indirect injection turbocharged diesel engine running at different engine speeds and loads were investigated. Experimental results showed that the ethanol addition reduced CO, soot and SO2 emissions, although it caused some increase in NOx emission and some power reductions due to lower heating value of ethanol. Improvements on emissions were more significant at full load rather than at partial loads. |
| 9. | ANALYSING SOLAR-WIND HYBRID POWER GENERATING SYSTEM Mustafa ENGİN, Metin ÇOLAK Pages 225 - 230 In this paper, a solar-wind hybrid power generating, system that will be used for security lighting was designed. Hybrid system was installed and solar cells, wind turbine, battery bank, charge regulators and inverter performance values were measured through the whole year. Using measured values of overall system efficiency, reliability, demanded energy cost per kWh were calculated, and percentage of generated energy according to resources were defined. We also include in the paper a discussion of new strategies to improve hybrid power generating system performance and demanded energy cost per kWh. |
| 10. | THE EFFECTS OF THE AİR POLLUTANTS ON CARBONATED BUİLDİNG STONE Lokman Hakan TECER Pages 231 - 237 The pollutant emissions that are thrown into the atmosphere as a result of the fossile fuel usage for either energy production, cause deterioration of the building stones in addition other environmental problems. Especially, SO2 and NOx have negative effects on the historical buildings in all over the world which are made of carbonate stones. These effects can be observed as the deterioration of the carbonate building stones by with the change of their chemical structures. This study presents the result of surveys which analyse the deterioration mechanism of CaCO3 major-constituent building stones by air pollutants. The buildings in urban areas are destroyed by air pollutants and meteorological conditions depending on their material characteristics. The main sign of the mentioned destroy is the gypsum formation that can go from the surface of the stone to inner parts. In the following pores of the stones cyclic crystallizations and melting, micro cracks and a loss of material are formed. These deterioration effects become more serious with the increasing pollution levels |
| 11. | VACUUM STEAMING PROCESSES APPLIED TO YARNS, ITS APPLICATION FIELDS AND IMPROVEMENTS Özcan ÖZDEMİR, Sibel ŞARDAĞ Pages 239 - 248 The new techniques used today focus mainly on increases in production speed. For this reason yarns to be used in high speed machines is required to be of high quality. On the other hand high speed frequently causes the degree of yarn moisture to fall minimum level. This decreases in the degree of yarn moisture have negative effects on yarn strength. Since better moisture level increases the yarn strength, yarn is worked more efficiently in weaving and knitting. However each production step in textile plants causes tension in yarn and fibre. Yarns tend to snarl in order to relax themselves.Tension and snarling may lead to problems in the following proceses, thus decreasing productivity. Therefore, the moisture content of yarns should be increased and their tension should be eleminated. In this article we have studied vacuum steaming widely used to remedy above mentioned yarn problems, its application fields and new improvements in this field. |
| 12. | THE EFFECTS OF MACHINES USED IN APPAREL COMPANIES TO THE PROFITABILITY Zümrüt BAHADIR ÜNAL, M. Çetin ERDOĞAN, Ziynet Öndoğan Pages 249 - 255 There are strong competition conditions at the market of ready made garment products which has an important part of world trade. In this sector, the technology development and research facilities have an important place because of the quality and technology are at the priority position. In our country, Turkey, lots of manufacturers tend to added valued and profitable products instead of usual, low priced and low added valued products. In this situation, new technologies must be used. But the usage of this kind of tecnologies could not be suitable for every company. The sewing automat is a kind of system group that can do any kind of sewing operation by itself. These kinds of complex machines need less number but more skilfull of workers. Decreasing of order quantities, fastly changing product and production types are given necessary to the workers for suiting these changes. In this paper, increasing of production quantity without changing quality was researched. For this purpose, ideal production method was proposed with the comparision of classical sewing machines and sewing automats for the point of production methods view. |
| 13. | HYDROGEOCHEMICAL INVESTIGATION OF ORTAKÇI HOT AND MINERALIZED SPRING (BUHARKENT-AYDIN) Mustafa KAYA, Ali GÖKGÖZ Pages 257 - 266 The temperature and discharge of the Ortakçı hot and mineralized water are 48.1 °C and 2.4 l/s, respectively. The spring has being formed as a result of ascending geothermal fluid due to the tectonic activity of the region. The geothermal fluid within joints has not been reached to chemical equilibrium with host rock which consists of gneiss, quartzite and schist. Ortakçı thermal water is the type of Na-SO4-HCO3 and subsurface temperature calculated using chemical geothermometers is about 80 °C. |
| 14. | ANALYSIS OF TOWING HOOKS OF CARS K. Turgut YÜKSEL, Rahman Çakır Pages 267 - 275 Towing hooks generally are assembled to vehicles as accessory. They are used to tow caravans and trailers having no engine, which provide accommodation and haulage of loads, respectively. So, the transport capacity of cars is increased safely. Towing hooks require different constructive structures due to different chassis or monocoque body of each car type; hence they are to be manufactured and assembled in small- or middle-size factories as per order. In this study, three different constructions of towing hook are modelled and structurally analysed. The results obtained are compared with each other to improve the structural strength. |
| 15. | SPEED CONTROL OF DC MOTOR WITH PIC 16F877 İlhami ÇOLAK, Ramazan BAYINDIR Pages 277 - 285 In this study, a PI controlled separately excited direct current (DC) motor speed has been controlled using PIC 16F877 controller. In the PIC 16F877 programming as a PI controller, the speed of the motor is expected to follow the reference speed. Speed of the motor is measured by a tacho generator and then, the voltage applied to the motor is adjusted by a semiconductor power switch using pulse width modulation (PWM) technique. Drive circuit was tested with 0.9 kW DC motor. Experimental results show that the drive circuit developed is very simple, useful, sensible, economical and flexible to apply for different applications. |
| 16. | THE INSULATION PROBLEMS ON PORCELAIN INSULATORS Engin ÇETİN, N. Lerzan ÖZER, Meriç ÇETİN Pages 287 - 292 Porcelain insulators used on electrical institutions are important materials to provide system reliability and material insulation. Specification of raw materials of insulators and environmental factors affect insulator strength and operation. In this study, environmental factors and materials used on porcelain insulator manufacturing are examined and also their influence on system reliability and insulation are investigated. |
| 17. | LIQUID-LIQUID EQUILIBRIA OF THE TERNARY SYSTEMS PROPIONIC ACID - WATER - SOLVENT (n-AMYL ALCOHOL AND n-AMYL ACETATE) Dilek ÖZMEN Pages 293 - 300 The experimental liquid-liquid equilibrium (LLE) data have been obtained at 25 oC for ternary systems propionic acid-water-n-amyl alcohol and propionic acid-water-n-amyl acetate. The reliability of the experimental tie line data are checked using the methods of Othmer-Tobias and Hand. The distribution coefficients and separation factors were obtained from experimental results and are also reported. The predicted tie line data obtained by UNIFAC method are compared with experimental data. It is concluded that n-amyl alcohol and n-amyl acetate are suitable separating agents for dilute aqueous propionic acid solutions. |
| 18. | MODELLING AND SIMULATION OF A SINGLE-ZONE HEATING AND VENTILATION SYSTEM Mesut ŞENGİRGİN, Erhan PULAT Pages 301 - 307 In this study, modelling and simulation results of a single-zone heating and ventilation system of a large office room are introduced. Heating system is controlled by an on-off controller. By considering the sinusoidal outdoor air tempareture variation and various outdoor/return air ratios as input parameters, dynamic behaviour of room air tempereture are investigated. For this purpose, MATLAB/Simulink code is used. |
| 19. | UTILISATION OF ALTERNATIVE MATERIALS IN MANUFACTURING OF MUD BRICK Hanifi BİNİCİ, Orhan AKSOĞAN, Hasan KAPLAN Pages 309 - 316 The population in the rural area of Turkey has increased due to KKP (in Turkish Köy-Kent Proje). Most of the buildings in the area are made out of limestone and adobe. But this material does not have sufficient resistance to earthquakes. The research in the field of construction at The University of Cukurova elaborates on the mechanical properties and workability of raw materials such as fibre, wheat stem, strafor, basaltic pumice and clay. The production of bricks using a significant fraction of mixed waste from wheat and different ratios of clay mixed with fibre, strafor, cement, gypsum, lime and basaltic pumice was investigated. This paper presents the use of waste in the construction of soft bricks at the KKP. The results of this study suggests that using these materials have many advantages such as energy savings, low cost and improvements in the final properties of products. |