Browsing by Author "Tekìn, Yücel"

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Effect of moisture content on the prediction of cation exchange capacity using visible and near infrared spectroscopy
(WFL Publication, 2013) Mouazen, Abdul Mounem; Tümsavaş, Zeynal; Tekìn, Yücel; Uludağ Üniversitesi/Ziraat Fakültesi/Toprak Bilimi ve Bitki Besleme Bölümü.; Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu/Makine Ve Metal Teknolojileri.; J-3560-2012; 6507710594; 15064756600
his study was undertaken to investigate the effect of moisture content (MC) on the prediction accuracy of the cation exchange capacity (CEC) of soils collected from Turkey using a fibre-type Vis-NIR spectrophotometer. The diffuse reflectance spectra of 150 soil samples were measured under 6 gravimetric MC levels of 0, 5, 10, 15, 20 and 25%. The results showed that the effect of MC on the prediction accuracy of CEC was nonlinear. Due to the direct spectral response in the NIR range, the prediction of CEC in the independent validation set was successful with a root mean square error of prediction (RMSEP) ranging from 5.82 to 8.14% and a ratio of prediction deviation (RPD) ranging from 1.59 to 2.14. The highest accuracy achieved for CEC was with the 10 and 15% MC soil samples (RMSEP 5.82%; RPD 2.14 and 2.12, respectively), and the lowest accuracy was found for wet soil samples with a 20% MC (RMSEP 8.14%; RPD 1.59). These results suggested that there was a clear effect of MC on the prediction of CEC. Because the differences between the models at different levels of MC were significant for CEC.
Engine and winter road test performances of used cooking oil originated biodiesel
(Pergamon-Elsevier Science, 2005-05) Çetinkaya, Merve; Karaosmanoğlu, Fìlìz; Ulusoy, Yahya; Tekìn, Yücel; Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu/Tarım Ekipmanları ve Makineleri Programı.; AAG-6056-2021; J-3560-2012
Biodiesel is a renewable and environmentally friendly alternative fuel that can be used in Diesel engines with little or no modification. Low cost feedstocks, such as waste oils. used cooking oil and animal fats, are important for low cost biodiesel production. The objective of this study was to investigate the engine performance and the road performance of biodiesel fuel originated from used cooking oil in a Renault Megane automobile and four stroke, four cylinder, F9Q732 code and 75 kW Renault Megane Diesel engine in winter conditions for 7500 km road tests in urban and long distance traffic. The results were compared to those of No. 2 Diesel fuel. The results indicated that the torque and brake power output obtained during the used cooking oil originated biodiesel application were 3-5 % less then those of No. 2 Diesel fuel. The engine exhaust gas temperature at each engine speed of biodiesel was less than that of No. 2 Diesel fuel. The injection pressures of both fuels were similar. Higher values of exhaust pressures were found for No. 2 Diesel fuel at each engine speed. As a result of the No. 2 Diesel fuel application, the engine injectors were normally carbonized. After the first period, as a result of winter conditions and insufficient combustion. carbonization of the injectors was observed with biodiesel usage. As a result of the second period, since the viscosity of the biodiesel was decreased, the injectors were observed to be cleaner. Also. no carbonization was observed on the surface of the cylinders and piston heads. The catalytic converter was plugged because of the viscosity in the first period. At the second period, no problem was observed with the catalytic converter.
Regional wind energy characteristics for Istanbul, Turkey
(Taylor, 2008) Vardar, Ali; Tekìn, Yücel; Okursoy, Rasim; Uludağ Üniversitesi/Ziraat Fakültesi/Tarım Makinaları Bölümü.; Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu/Tarım Makinaları Bölümü.; 0000-0001-6349-9687; J-3560-2012; AAH-5008-2021; 15049958800; 15064756600; 6506218306
In this study, wind energy for Istanbul, which is the biggest city of Turkey both in terms of population density and industrialization was analyzed. Meteorological data of 7 stations in Istanbul is used in this study. Daily, monthly, and annual wind speed values and frequency distributions show that Kumkoy and, Sile stations have higher wind energy potential than other stations. Frequencies of wind speeds higher than 5 ms(-1) are in turn 55.2% and 53.2% for both stations. Annual energy value that can be generated with a Nordex N60 wind turbine was calculated as 1,207 MWh in Kumkoy, 955 MWh in, Sile, 535, 454, 221, 519, and 113 MWh in turn in Goztepe, Kirecburnu, Baheckoy, Florya, and Kartal. It was determined that wind blows dominantly from the geographical directions between northwest and northeast and from south-southwest throughout Istanbul.