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Öğe Effect of time horizon on wind speed prediction with ann(Yıldız Technical University, 2018) Pusat, Şaban; Akkoyunlu, Mustafa TahirProper utilization of renewable energy sources in electricity production is inevitable due to the environmentalconcerns and global warming fight. Therefore, predictability of renewable electricity is a very significant issue fora long time. Main aim of this study, different from the literature, is to investigate the change of wind speedprediction errors for different time horizons. Different prediction time horizons (10, 30, 60, 90 and 120 minutes)were used, and the results were compared through the error measures and the regression values. The mean squarederrors and the regression values vary between 0.819 and 5.570, and between 77.8% and 97.1%, respectively. Theprediction error changes almost logarithmically, and the rate of change decreases with the increasing time horizon.A new analysis approach was proposed to see the change of the prediction error with time horizon. The equation,y 1.5413ln(x) - 2.7428, representing the change of the mean squared error with time horizon was obtained.Öğe Doğrusal katılaştırılmış Al-%13ağ.Mg2Si alaşımının mikroyapı karakterizasyonu(2017) Kaygısız, YusufIn the present work, effect of growth rates on microstructure for directionally solidified Al-13wt. %Mg2Si pseudoeutectic alloy at a constant temperature gradient were studied. The composition of pseuodoeutectic Al-Mg2Si alloy in Al-Mg-Si system was chosen to be Al13wt.%Mg2Si (Al–8.75wt.%Mg–4.25wt.%Si) to growth the eutectic phases from ternary liquid.Directional solidification process were carried out with different growth rates (V8.33–175.0 µm/s) at a constant temperature gradient (G6.63 K/mm) by using synchronous motors running at different speed by Bridgman-type furnace.According to phase diagrams and EDX results light grey, black and dark grey phases were identified as quenched liquid phase, Mg2Si coral-like and –Al matrix, respectively.As the growth rate is increased, the eutectic spacings decrease. When the growth rate of samples increases from 8.33 to 175 m/s the average eutectic spacing for Mg Si 2 decrease from 7.12 to 1.70µm. The highest eutectic spacing was obtained at the minimum growth rate and a constant temperature gradient (V8.33 µm/s, G6.68 K/mm). On the other hand, the smallest eutectic spacing was measured at the maximum value of growth rate and a constant temperature gradient (V175.0 m/s, G6.68 K/mm). The dependency of lamellar spacing () on growth rates (V) were obtained as 0.45 16.95 2 Mg Si V for AlMg2Sipseudoeutectic alloy.The bulk growth rate was also determined as V 2 Mg Si 2 408.96 µm3 /s by using the measured values of Mg Si 2 and V.Öğe Enerji Amaçlı Aspir Tarımında Farklı Fosfor Uygulamalarının Biyodizel Kalitesine Etkileri(2015) Öğüt, Hüseyin; Oğuz, Hidayet; Şahin, Seda; Gezgin, Sait; Aydın, FatihAspir; Genetik kaynağı Anadolu olan ve Türkiye'de biyodizel üretiminde hammadde olarak kullanılmaya başlanan bir bitkidir. Üretimi giderek artan aspirin, Remizbey 05 ve Balcı çeşitlerinin tarımı yapılmaktadır. Bu çalışmada da farklı fosfor gübrelemesi yapılmış Remzibey 05 ve Balçı çeşitlerinden elde edilen yağlardan biyodizel üretimi yapılmıştır. Bu amaç için önce yağdaki fosfor uzaklaştırılmıştır. Çalışma, tohum ve yağdaki fosfor oranını azaltarak biyodizel üretim maliyetini düşürmeyi hedeflemektedir. Fosfor gübrelemesinde 0, 2, 4, 6, 8 ve 10 kg/ha normları kullanılmıştır. Tohumlardan elde edilen yağların asit kompozisyonu belirlenmiş ve üretilen biyodizelin teknik özellikleri ortaya konulmuştur.Öğe The Effects of E-B Diesel Fuel Blends on Engine Lubricating Oil in a Single Cylinder Diesel Engine(2017) Aydın, Fatih; Öğüt, HüseyinIn this study, biodiesel was produced by turning the raw oil, obtained from safflower seed, into Safflower Oil Methyl Ester by transesterification method. Mixing the biodiesel fuel, which was obtained from the safflower, with diesel fuel by adding bioethanol at the rate of 2.5% and 5% and volumetrically in inverse proportion, test fuels were acquired in the form of D100, E2.5B2.5D95, E5B5D90, E5B2.5D92.5 and E2.5B5D92.5. The tests of the diesel fuel and the obtained fuel blends were carried out related to the fuel features; kinematic viscosity, density, water content, pH, color, calorific value, flash point, cloud, pour and freezing points, copper strip corrosion test, iodine number, cold filter plugging point and cetane number. Also, the obtained blend was tried and examined on a four-cycle, single cylinder and on water cooled diesel engine with direct injection fuel system. The engine ran for 100 hours under partial load and the samples were taken from the engine oil at specific times and wear elements were searched. As a result of the analysis of the samples taken from engine lubricating oil, it was observed that as the engine run time increased, the wear elements in the samples increased, too. As a result of ICP oil analysis, the amount of wear elements such as iron, copper, aluminum, lead and chromium in engine lubricating oil were stated diagrammatically. It was determined that the use of E2.5B5D92.5 produced better results than the other types of fuels in terms of wear elements.
