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Batman, Turkey

Levent A.,Batman University
Diamond and Related Materials | Year: 2012

In this study, a boron-doped diamond electrode was used for the electroanalytical determination of melatonin in the pharmaceutical tablet and urine samples by square-wave voltammetry. Melatonin yielded a well-defined voltammetric response in Britton-Robinson buffer, pH 3.0 at + 0.88 V (vs. Ag/AgCl). Using the optimal square-wave voltammetry conditions, the oxidation peak was used to determine melatonin in the concentration range of 5.0 × 10 7 M to 4.0 × 10 6 M (r = 0.998, n = 8), a detection limit of 1.1 × 10 7 M (0.025 μg/mL) and relative standard deviation was 2.06% at the 2.0 × 10 6 M level (n = 10). Recoveries of melatonin were in the range of 97.67-105%, for both tablet and spiked human urine samples. © 2011 Elsevier B.V. All rights reserved. Source


Altun S.,Batman University
Energy Education Science and Technology Part A: Energy Science and Research | Year: 2011

Bio diesel is an oxygenated diesel fuel obtained from vegetable oils or animal fats via transesterification reaction. The fuel properties such as viscosity, density, cetane number and heating value are very important for determining the suitability of bio diesel as a diesel engine fuel. These fuel properties mainly depend on the feedstock which is used in the bio diesel production. In this study, the effect of bio diesels produced from different feed stocks such as inedible animal tallow, crude canola oil and canola oil blended with animal tallow on the fuel properties were experimentally investigated. Bio diesel fuels and their blends with petroluem diesel fuel were compared with petroleum diesel (petrodiesel). The results showed that the viscosity and density of all the methyl esters were higher than that of petrodiesel, while the heating values of the methyl esters was lower. Besides, the viscosity and the density of methyl esters are within the bio diesel standards, except for animal tallow methyl ester and it was slightly out of the specification EN 14214. Animal tallow bio diesel has the highest cetane number than those of other fuels include petrodiesel. It is concluded that bio diesels and their blends with petrodiesel have suitable fuel properties, especially cetane numbers, for diesel combustion process. © Sila Science. Source


In this work, three biodiesel fuels with iodine numbers ranging from 59 to 185 were tested in a direct-injection diesel engine powered generator set at constant speed of 1500 rpm under variable load conditions to investigate the effect of the degree of unsaturation of biodiesel fuels, which are quantified by the iodine number, on the performance and exhaust emissions of a diesel engine. The increase in unsaturation involved a decrease in cetane number, and therefore, allowed for the maximization of the effect of the cetane number, while other properties, such as oxygen content, heating value, and viscosity, varied within a small range. Experimental results showed that biodiesel fuels resulted in lower emissions of nitrogen oxides, carbon monoxide, and smoke opacity, with some increase in emissions of unburned hydrocarbons. With their low energy content, neat biodiesel fuels resulted in an increase in fuel consumption compared to the conventional diesel fuel (ultra-low sulphur diesel). The degree of unsaturation of biodiesel fuels had effects on engine emissions via its effect on the cetane number and adiabatic flame temperature while engine performance was not significantly affected by the type of biodiesel fuel or its degree of unsaturation. The biodiesel having lowest iodine number had highest cetane number, and lowest density and adiabatic flame temperature, which was good to reduce NOx emissions, as it agreed with experimental results. Additionally, more unsaturated biodiesel fuels showed higher NOx emissions, smoke opacity, and lower HC emissions. It can be said that cetane number and adiabatic flame temperature are responsible for such results. © 2013 Elsevier Ltd. All rights reserved. Source


Altun S.,Batman University
Energy Education Science and Technology Part A: Energy Science and Research | Year: 2011

Vegetable oils and animal fats are widely investigated as a alternative fuel for diesel engines because of their high cetane number. However, animal fats are highly viscous and mostly in solid form at ambient temperature that they need modifications before using them in diesel engines. Pre-heated, blending, transesterification and emulsification are well known to improve usage of animal fats in diesel engines. In this study, biodiesel was produced from a hybrid feedstock (60% crude canola oil/40% inedible animal tallow) by transesterification and tested in a DI diesel engine for determining exhaust emissions and comparing those of biodiesel from pure animal tallow. Biodiesel fuels were tested as blends in diesel fuel (50% biodiesel and 50% diesel fuel). The experimental results show that, compared with animal tallow biodiesel blend, hybrid feedstock biodiesel blend has higher viscosity, density, brake specific fuel consumption, CO and NO x emissions and a lower cetane number, brake thermal efficiency. © Sila Science. Source


Argunhan Z.,Batman University
Energy Education Science and Technology Part A: Energy Science and Research | Year: 2011

In this study, expressions for optimum radius of a circular flat plate solar collector and the optimum insulation thickness distribution are derived by using the concept of solar gain, which maximizes the life-cycle savings. For the specified condition the optimum radius has been found as 2.14 m and the optimum insulation thickness distribution on back of collectors has been formulized. The insulation material thickness distribution has been determined by performing a detailed dimensional analysis; therefore heat loss is minimized, and results are presented in graphics. © Sila Science. Source

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