International Journal of Engineering & Applied Sciences

11-21

Authors: Kamran Dawood [1] , Mehmet Aytac Cınar [2] , Bora Alboyacı [3] , Olus Sonmez [4]

Different transformer models are examined for the calculation of the no-load losses using finite element analysis. Two-dimensional and three-dimensional finite element analyses are used for the simulation of the transformer. Results of the finite element method are also compared with the experimental results. The Result shows that 3-dimensional provide high accuracy as compared to the 2 dimensional full and half model. However, the 2-dimensional half model is the less time-consuming method as compared to the 3 and 2-dimensional full model. Simulation time duration taken by the different models of the transformer is also compared. The difference between the 3-dimensional finite element method and experimental results are less than 3%. These numerical methods can help transformer designers to minimize the development of the prototype transformers.

36-50

Authors: Vebil Yıldırım

A broad parametric study is carried out to investigate the effects of both the inhomogeneity parameter, and a profile index of Stodola’s hyperbolic function on the static response of such structures subjected to both the inner and outer pressures. The investigation is based on the analytical formulas lately published by the author. The effects of those parameters on the variation of the radial displacement, the radial and hoop stresses are all graphically illustrated for an annulus pressurized at its both surfaces. It is observed that, especially, the variation of the hoop stress in radial coordinate is closely sensible to variation of those parameters. For the chosen problems it was observed that one of two materials whose Young’s modulus is higher than the other is better to locate at the inner surface of the disc having divergent profile to get reasonable maximum hoop stresses. However much smaller radial displacements may be obtained by using positive inhomogeneity indexes for all discs whose surfaces host a material whose Young’s modulus is smaller than the other. To reach a final decision, analytical formulas such as those used in the present study together with a failure criteria such as Von Mises and Tresca become indispensable means in a design process.

60-74

Authors: Mohammed Qusay Mahmood Alkattan [1] , Muayad Saadallah Khaleel Khaleel [2]

Mosul Dam is one of the important dams in Iraq, it suffers like other dams from the problem of sediment accumulation in the lake. The daily surface runoff was estimated from seven main valleys in the left bank of the lake during the period (1/1/1988-31/8/2016) by applying SWAT model. The model performance was assessed using the statistical criteria R2, IOA, NSE and T-Test, the results were good. The averages annual surface runoff from the main valleys to the lake ranged between 3.3*106 m3 to 42.1*106 m3. The daily sediment load was estimated by four methods, Bagnold method was used in SWAT sediments transport simulation, while Yang, Toffaletti methods and Excess Shear Theory were programed by MATLAB, The performance of sediments transport simulation using Bagnlod, Yang and Excess Shear Theory methods was assessed using the same four statistical criteria and the results were good, The averages annual sediment load from the main valleys to the lake were (5.78*103 - 68.62*103), (1.49*104 - 42.13*104), (8.46*103 - 160.77*103) and (4.26*104 - 78.6*104) tons for Bagnold, Yang, Excess Shear Theory and Toffaletti methods, respectively. The valley Jardiam is the main supplier of sediments to the left side of the dam lake with 56%.

87-97

Authors: Kadir Mercan [1] , Ömer Civalek [2]

Theories which consider small scale effect have a great importance on analysis in micro and nano scale. In present paper, three kind of nanotubes (Carbon Nanotube (CNT), Boron Nitride Nanotube (BNNT), and Silicon Carbide Nanotube (SiCNT)) are analyzed in case of buckling on two parameters elastic foundation. Three different small scale theories (Nonlocal Elasticity Theory (NET), Surface Elasticity Theory (SET), and Nonlocal Surface Elasticity Theory (NET&SET)) are applied to calculate the buckling loads. Also Classical Euler-Bernoulli Beam Theory (CT) is used to see the effect of small scale effective theories. Comparative results are given for simply supported nanotubes in figures.