in this paper, the reorganization of the denominator of the discrete derivative and nonlocal approximation of nonlinear terms are used in the design of nonstandard finite difference schemes (nsfds). numerical examples confirming then efficiency of schemes, for some differential equations are provided. in order toillustrate the accuracy of the new nsfds, the numerical results are compared with s...

in this paper, we present legendre wavelet method to obtain numerical solution of a singular integro-differential equation. the singularity is assumed to be of the cauchy type. the numerical results obtained by the present method compare favorably with those obtained by various galerkin methods earlier in the literature.

the depth control systems used in iranian tractors are mechanical and they produce variable tillage depth in uneven field surface. in this research a rotary type electronic control valve was designed and constructed. by using this valve, electro-hydraulic tillage depth control system was developed and installed on the tractor. the control system was composed of: a depth sensor, a programmable l...

Singular perturbation problems have been studied by many mathematicians. Since the approximate solutions of these problems are as the sum of internal solution (boundary layer area) and external ones, the formation or non-formation of boundary layers should be specified. This paper, investigates this issue for a singular perturbation problem including a first order differential equation with gen...

the bicuspid aortic valve is known to be the most common congenital cardiac malformation, with an approximate incidence rate of 1-2% in the general population. most patients are unaware of the disease until the onset of infective endocarditis, which is a life-threatening complication that may affect a heart valve or other cardiac structures at the site of endothelial damage. a 22-year-old man p...

abstract background: few attempts were made for alleviating the physical/psychological problems among the cardiac valve–replaced patients and no comprehensive study was done based on the experiences of such patients. this study was undertaken to describe the stressful experiences of the heart valve-replaced patients. materials and methods: in this qualitative study performed during 2012-2013 wi...

in this study it has been tried, to compare results and convergence rate of sensitivity analysis and conjugate gradient algorithms to reduce fuel consumption and increasing engine performance by optimizing the timing of opening and closing valves in xu7/l3 engine. in this study, considering the strength and accuracy of simulation gt-power software in researches on the internal combustion engine...

Herein, we present the case of a 10-year-old child suffering from right-sided infective endocarditis with ventricular septal defect. Echocardiography revealed multiple rare large vegetations on the pulmonary valve extending into pulmonary artery along with a large vegetation over the septal leaflet of the tricuspid valve.