Yazar "Çelik, Mehmet" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim
    Öğe
    The effect of washing process on fuel properties in biodiesel production
    (SILA SCIENCE, 2012) Çelik, Mehmet; Kahraman, Ali; Acaroğlu, Mustafa
    The importance of fuel for world's economy and politics is an undebetable truth. Rapid decrease of world's energy resources made this unrenewable energy resource strategic. Since traditional fossil energy resources are limited and greenhouse gas emissions are becoming a greater concern, research is now being directed towards the use of alternative renewable fuels that are capable of fulfilling an increasing energy demand. One of the more promising approaches is the conversion of vegetable oils (VOs) and other feedstocks, which primarily contain triglycerides (TGs) and free fatty acids (FFAs), into biodiesel.The quality of biodiesel is related to the oil, catalyst type and quantity, methanol's oil/molar rate, reaction heat and time, purity and property of alcahols, production method, quality of washing phase, decomposition of glycerin and store conditions. In this study, raw biodiesel derived from refined cottonseed oil by transesterification has obtained biodiesel by washing with distillated pure water (DW) and deionizationed water (DEW). Physical-chemical properties of biodiesel and the effect of washing processes to the fuel properties are investigated.
  • Küçük Resim Yok
    Öğe
    Investigation of Effect of n-hexane Additives in Biodiesel in Combustion and Exhaust Emissions in Diesel Engines
    (2017) Çelik, Mehmet; Bayındırlı, Cihan; Demiralp, Mehmet; Örs, İlker
    There are various studies concerning biodiesel fuel and its spraying, combustion and emission properties within the diesel engines. In the diesel engines, the hazardous emissions such as carbonmonoxide (CO), carbondioxide (CO2), hydrocarbon (HC) and particle matter (PM) decreased along with the use of biodiesel. But a slight increase in azotoxit (NOx) emissions was observed due to the use of biodiesel which is an oxygenated fuel. In this study; by volume 4% 12% and 20% n-hexane were added in biodiesel which produced by transesterification method from cottonseed oil. Engine tests were carried out at 6 min-1. The maximum moment obtained at 1400 min-1. The maximum increase in moment is 3.95% in CHX20 fuel, while the specific fuel consumption is reduced by 5.52%. At 1400 min-1, the maximum of cylinder pressure and heat dissipation is increased by increasing of additive ratio. As the n-hexane ratio increases, the emissions of CO, HC and smoke decrease while NOx emissions increase
  • Küçük Resim
    Öğe
    Kuranda müminlerin vasıfları
    (Selçuk Üniversitesi Sosyal Bilimler Enstitüsü, 2009) Çelik, Mehmet; Gölcük, Şerafettin
    Tezimiz, Kur'ân âyetlerinde ifadesini bulan mü'min ve mü'min kişinin vasıfları konusunu ele almayı amaçlamaktadır. Bunun için başta Kur'ân olmak üzere tefsir, kelam, hadis ve çeşitli ilmî kaynaklardan yararlanarak bu konuya açıklık getirmeye çalıştık.
  • Küçük Resim Yok
    Öğe
    Serum Levels of Lipids, Lipoproteins and Apolipoproteins in Patients with Coronary Artery Disease Documented by Angiography
    (1996) Koçyiğit, Abdurrahim; Akkuş, İdris; Vural, Hüseyin; Gök, Hasan; Çağlayan, Osman; Durmuş, Bilal; Çelik, Mehmet; Menekşe, Elif
    Serum Triglyceride (TG), total cholesterol (TC), phospholipid (PL), Apo A-I, Apo B, lipoprotein (a) (Lp(a)), high-density lipoprotein cholesterol (HDL-C,HDL2-C, HDL3-C), low density lipoprotein cholesterol (LDL-C) and free cholesterol (FC) levels of 108 subjects with and without coronary artery disease (CAD) documented by coronary angiography were investigated. Subjects were classified as normal and patients with CAD according to degree of vascular stenosis. Those with ? 50% stenosis in at least one major coronary artery branch were referred as patients with CAD. Patients consisted of 27 women aged 38-73 years and 44 men aged 31-72 years. Controls were 20 women aged 38-77 years and 17 men aged 38-77 years. Men with CAD had significantly higher plasma Lp(a), TC and LDL-C levels than the male controls. They also had significantly lower levels of Apo A-I, HDL-C and HDL2-C. Also, ratios of Apo B/Apo A-I and LDL-C/HDL-C were higher, whereas HDL2-C/HDL-C, HDL-C, TC and HDL2-C/HDL3-C ratios were lower than those of controls. On the other hand plasma Lp(a), Apo B, TC and FC levels of the women with CAD were significantly higher whereas HDL-2-C level was lower compared to the values of the female controls. Ratios of Apo B/Apo A-I and LDL-C/HDL-C were significantly higher, HDL2-C/HDL-C and HDL3-C and HDL2-C/HDL3-C ratio were lower than those of female controls. We concluded that Lp(a) is an independent risk factor for CAD and HDL2-C and HDL2-C/HDL3-C ratio are the best indicators of CAD both in men and women.