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Öğe Otomotiv fren balatalarının sürtünme performansında sic etkisi(Uludağ Üniversitesi, 2012-06) Altun, Şehmus; Öner, Cengiz; Sugözü, İlkerBu çalışmada, yüksek mukavemet, düşük aşınma, daha fazla yük ve sıcaklık dayanımı özelliklerine sahip SiC içeren balata numunelerinin sürtünme katsayısı ve aşınma dayanımına etkisi incelenmiştir. Balata bileşeni içerisine %5, %10 ve %15 SiC ilave edilmiştir. Sonuç olarak, SiC oranı arttıkça aşınma direnci artmış ve sürtünme katsayısı azalmıştırÖğe Uluslararası kültürel miras mevzuatı(Kültürel Mirasın Dostları Derneği, 2007) Aydın, Mahmut; Öz, Ali Kazım; Güner, Saadet; Aydın, Mahmut; Öz, Ali Kazım; Güner, Saadet; Kapan, DenizÖğe N-type InP Schottky diodes with organic thin layer: Electrical and interfacial properties(Journal of Vacuum Science & Technology B, 2010-03) Güllü, Ömer; Turut, AbdulmecitThe rectifying junction characteristics of methyl red (MR) organic film on n-type InP substrate have been studied. It has been observed that MR-based structure shows an excellent rectifying behavior and that the MR film increases the effective barrier height by influencing the space charge region of the n-type InP. The barrier height and ideality factor values for this structure have been obtained as 0.75 eV and 1.93 from the forward bias current-voltage characteristics, respectively. By using capacitance-voltage characteristics at 1 MHz, the barrier height and the carrier concentration values have been calculated as 0.93 eV and 5.13×1015 cm−3, respectively. The energy distributions of the interface states and their relaxation times have been determined from the forward bias capacitance-frequency and conductance-frequency characteristics. Moreover, it was seen that both the interface-state density and the relaxation time of the interface states decreased with bias voltage from experimental results.Öğe Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine(Elsevier, 2009-02-15) Altun, Şehmus; Öner, CengizIn this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NOx), sulphur dioxide (SO2) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NOx emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.Öğe Atık kızartma yağlarının alternatif dizel motor yakıtı olarak değerlendirilmesi(TMMOB Makina Mühendisleri Odası, 2011) Adin, Hamit; Yaşar, Fevzi; Altun, ŞehmusÖğe The effect of Plantago major Linnaeus on serum total sialic acid, lipid-bound sialic acid, some trace elements and minerals after administration of 7,12-dimethylbenz(a)anthracene in rats(SAGE, 2012-04) Oto, Gökhan; Ekin, Suat; Özdemir, Hülya; Levent, Abdulkadir; Berber, İsmetThe present study was designed to evaluate the effect of Plantago major Linnaeus (PM) extract on serum total sialic acid (TSA), lipid-bound sialic acid (LSA), some trace elements (copper (Cu), zinc (Zn) and iron) and mineral levels (magnesium, calcium and sodium) in Wistar albino rat administrated 7,12-dimethylbenz(a)anthracene (DMBA). Rats were divided into three equal groups (n = 6). Group I comprised the control group, group II was treated with DMBA (100 mg/kg, single dose) and group III was treated with DMBA (100 mg/kg single dose) and aqueous extract of PM 100 mg/kg/day for 60 days. After 60 days, statistical analyses showed that TSA and LSA levels in DMBA and DMBA + PM groups were significantly higher compared to the control group (TSA: p < 0.01, p < 0.05; LSA: p < 0.05, p < 0.05, respectively). Serum Zn levels were decreased in subjects treated with DMBA (p < 0.01) and DMBA + PM (p < 0.05) compared to the control group values. Serum Cu levels were increased in DMBA group and PM-treated group compared to the control group values. The results of this investigation showed that the levels of TSA and LSA changed significantly, which are sensitive markers for detecting the toxic effects of DMBA. On the other hand, observed decline in Zn levels in rats from DMBA + PM group might be due to decreased generation of free radicals and oxidative stress. Results from this study suggest that PM may be partially effective in preventing carcinogenesis initiated by environmental carcinogen DMBA.Öğe Görüntülerin esinleyici gücünün geleceğe yönelik yeni düşünceler oluşturmasındaki rolü(Ankara Üniversitesi, 2012-11) Uzun Aydın, Derya; Cereci, SedatÖğe The comparison of engine performance and exhaust emission characteristics of sesame oil-diesel fuel mixture with diesel fuel in a direct injection diesel engine(Elsevier, 2008-01-09) Altun, Şehmus; Bulut, Hüsamettin; Öner, CengizThe use of vegetable oils as a fuel in diesel engines causes some problems due to their high viscosity compared with conventional diesel fuel. Various techniques and methods are used to solve the problems resulting from high viscosity. One of these techniques is fuel blending. In this study, a blend of 50% sesame oil and 50% diesel fuel was used as an alternative fuel in a direct injection diesel engine. Engine performance and exhaust emissions were investigated and compared with the ordinary diesel fuel in a diesel engine. The experimental results show that the engine power and torque of the mixture of sesame oil-diesel fuel are close to the values obtained from diesel fuel and the amounts of exhaust emissions are lower than those of diesel fuel. Hence, it is seen that blend of sesame oil and diesel fuel can be used as an alternative fuel successfully in a diesel engine without any modification and also it is an environmental friendly fuel in terms of emission parameters.Öğe Karyotypes of some small mammals inhabiting the province of Diyarbakır Turkey(Mosul University, 2011) Ulutürk, Servet; Coşkun, Yüksel; El Naemy, A; Kaya, AlaettinÖğe Delphi programlama dili kullanılarak plastik enjeksiyon kalıplarında ürün maliyet hesabı ve yeni bir paket programın geliştirilmesi(e-Journal of New World Sciences Academy, 2010-07) Çelik, Yahya Hışman; Özek, Cebeli; Gürgüze, GürkanBu çalışmada, plastik enjeksiyon kalıplama tekniklerini kullanarak kalıplanan plastik ürünlerin maliyet analizini hesaplayan yeni bir program geliştirilmiştir. Geliştirilen maliyet programı için Delphi programlama dili kullanılmıştır. Program, enjeksiyon kalıplama teknikleri ile üretilen bir adet plastik ürünün maliyeti için veri bilgi girişinden seçilen değerlere göre hesaplama yapmaktadır. Elde edilen bilgilere bağlı olarak ham plastik malzeme maliyeti, kalıp maliyetine bağlı amortisman gideri, soket giderleri, işleme ve işçilik giderleri analiz edilerek plastik ürünün tahmini maliyeti hesaplanmaktadır. Programın geçerliliğini kontrol etmek için araçlardaki hava üfleme elemanı örneği seçilmiştir. Programdan elde edilen değerler gerçek değerlerle karşılaştırılarak programın geçerliliği kontrol edilmiştir. Bu verilere bağlı olarak geliştirilen paket program ile gerçek değerler arasında yaklaşık %9,7 kadar bir fark olduğu görülmüştür.
