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Keleolu Z.,Ondokuz Mayis University | Celenk Kaya E.,Gumuhane University | Kantekin H.,Karadeniz Technical University | Buyukgungor O.,Ondokuz Mayis University
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

In the title compound, C31H39Br2N 3O6S2, a 17-membered azamacrocyclic ligand containing two ether O and three aza N atoms, the three pendant aromatic rings form an E shape. The dihedral angles between the central benzene ring and the side ones are 17.8 (3) and 7.4 (3)°, and the dihedral angle between the tosyl rings is 10.6 (3)°. The methyl group is disordered over two orientations, with occupancies of 0.52 (15) and 0.48 (15). © 2010. Source


Dede T.,Karadeniz Technical University | Bekirolu S.,Gumuhane University | Ayvaz Y.,Yildiz Technical University
Applied Soft Computing Journal | Year: 2011

This study is concerned with encoding types such as value encoding and binary encoding for continuous and discrete optimization with a GA, which is coded in FORTRAN and considers stress and displacement constraints, in view of weight minimization of truss structures. Moreover, when continuous optimization is performed, the challenge of huge search space due to the effort of considering continuous set of design variables is overcame by a mechanism introduced as restricted range approach (RRA) in this study. In comparison with the literature, it is concluded that the program developed in this study can be effectively used in the weight minimization of truss structures. It is also came to the conclusion that value encoding overcomes the adverse effects of Hamming-cliff, and that value encoding requires less computer memory and time, never destroys the fit chromosome. © 2010 Elsevier B.V. All rights reserved. Source


Damla N.,Batman University | Cevik U.,Karadeniz Technical University | Kobya A.I.,Karadeniz Technical University | Celik A.,Giresun University | And 2 more authors.
Radiation Measurements | Year: 2011

In this study the distribution of natural radionuclides (226Ra, 232Th, 40K) in brick and roofing tile samples commonly used as building materials in Turkey was measured by using gamma spectrometry. The activity concentrations, radium equivalent activities (Raeq), representative level index, indoor absorbed dose rate in air values and annual effective dose due to the intake of the above-mentioned radionuclides in the brick and roofing tile samples were estimated to assess the radiation hazard for people living in dwellings made of the materials studied. The measured average activity concentrations of 226Ra, 232Th and 40K were 34 ± 14, 34 ± 13 and 462 ± 175 Bq.kg-1, respectively, for brick samples. For roofing tile, the average activity concentrations of 226Ra, 232Th and 40K were measured to be 34 ± 14, 33 ± 12 and 429 ± 161 Bq.kg -1, respectively. The concentrations for these natural radionuclides were compared with the reported data of other countries. The Raeq values of all samples were lower than the limit of 370 Bq.kg-1, equivalent to a gamma dose of 1.5 mSv.a-1 recommended by OECD. This study shows that the measured brick and roofing tile samples do not pose any significant source of radiation hazard and are safe to be used as building materials. Moreover, the experimental mass attenuation coefficients (μ/ρ) of brick and roofing tile samples were determined in the energy range 80-1332 keV using the gamma ray transmission method. The experimental mass attenuation coefficients were compared with theoretical values obtained using XCOM. It was found that the computed values and the experimental results of this work are in good agreement with those reported in the literature. The chemical compositions and structural analysis (XRD) of the brick and roofing tile samples are also presented. © 2011 Elsevier Ltd. All rights reserved. Source


Sezer I.,Gumuhane University
International Journal of Thermal Sciences | Year: 2011

This study investigates the use of dimethyl ether and diethyl ether in diesel engines as alternative fuels. A direct injection diesel engine was simulated via a thermodynamic cycle model for investigation. Thermodynamic and performance parameters besides emissions determined and compared for diesel, dimethyl ether and diethyl ether fuels at two different states. The results showed that dimethyl ether and diethyl ether presented a lower cylinder temperature and pressure, and thus a lower engine performance than diesel fuel for the equal injection conditions. The brake power declines about 32.1% and 19.4% at 4200 rpm while brake specific fuel consumption increases about 47.1% and 24.7% at 2200 rpm for dimethyl ether and diethyl ether, respectively. Engine performance for dimethyl ether and diethyl ether extensively improves for the same equivalence ratio condition, but a more amount of fuel is needed about 64% for dimethyl ether and 32% for diethyl ether. The gains in the brake power by dimethyl ether and diethyl are about 13.6% and 6% at 4200 rpm compared to diesel fuel. The brake specific fuel consumption is also higher about 43.5% for dimethyl ether and 23.6% for diethyl ether than diesel fuel. The brake thermal efficiency for dimethyl ether and diethyl is generally better than diesel fuel. The lower carbon dioxides are obtained by dimethyl and diethyl ethers at all conditions, while carbon monoxide and nitrogen oxide are slightly higher for dimethyl and diethyl ethers at equal equivalence ratio condition. © 2011 Elsevier Masson SAS. All rights reserved. Source


Akpinar A.,Gumuhane University | Akpinar A.,Karadeniz Technical University | Kaygusuz K.,Karadeniz Technical University
Renewable and Sustainable Energy Reviews | Year: 2012

Southeastern Anatolia Project (GAP) region in Turkey is rich in water for irrigation and hydroelectric power. The Euphrates and Tigris Rivers represent over 28% of the nation's water supply by rivers, and the economically irrigable areas in the region make up 20% of those for the entry country. Turkey has a total gross hydropower potential of 433 GWh/yr, but only 125 GWh/yr of the total hydroelectric potential of Turkey can be economically used. By the construction of new hydropower plants, 36% of the economically usable potential of the country would be tapped. The GAP region has a 22% share of the country's total hydroelectric potential, with plans for 22 dams and 19 hydroelectric power plants. Once completed, 27 billion kWh of electricity will be generated annually. © 2011 Elsevier Ltd. All rights reserved. Source

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