Effect of perturbation and oblateness of smaller primary on the linear stability in the restricted problem of three bodies.
The effect of perturbation in the coriolis and the centrifugal forces and oblateness of smaller primary on the stability of the triangular points in the restricted problem of the three bodies has been studied.
R.J.of Aleppo Univ,No15Approximate solution for partial differential equations of a non –homogeneous thick plat.
In this paper, we give a model of a Love-Kirshoff plate white periodic Cauchey Boundary conditions that means a mechanical structure in the linear elasticity theory, which is fixed punctually. We show that a mechanical frame which is fixed punctually has a behavior witch is near to the behavior of an entirely clamped structure. For this purpose we use a modified homogenization theory. And we give an estimation of the difference between the exact and approximate solution in regard to the number of fixation points. نقترح في هذا البحث نموذجاً رياضياً لتمثيل السلوك الميكانيكي المقارب لصفيحة مرنة من نوع لوف-كيرشوف مثبتة من حدودها بشكل نقطي وذلك باستخدام تقنية نظرية التجانس بعد تطويرها. حيث أن طريقة التجانس تسمح بالتغلب على الصعوبة الناتجة عن التجزئة الكبيرة جداً للمنطقة ،وذلك باستبدال المسألة الأصلية المعرفة على منطقة غير متجانسة وذات الخواص المتغيرة بشكل دوري بمسألتين معرفتين على خلية واحد (أي دور Y ( واللتين يتطلب حلهما عددياً جهداً ووقتاً أقل من المسألة الأصلية.
1st.sci.conf Al-AzharUniv.fac.sciApproximate solution for partial differential equations of a non-homogeneous thick plate
In this paper, we give an approximate mathematical model of a periodically non-homogeneous Love-Kirchhoff plate with periodic inclusions or perforations. Dealing with the variational formulation, we prove the existence and the uniqueness of a weak solution. The asymptotic expansion is used to derive the homogenized approximate problem and the first correction term. The use of the finite element method in such case is very complicated. The homogenization method 1,6 leads to replace this complicated finite element problem in the whole domain by two simple problems in one cell Y.
Mans.Sci.Bull.vol22(2) P137-148Influence of Discretization Methods on Digital Low Pass Filter Performance
In this paper we study the influence of discretization methods that transform continuous systems to digital systems. This evaluation is applied on the performance of a digital filter used to detect a dumped sinusoidal signal. We consider the comparison between zeros and poles locations in the unit circle. In addition, we compare the time and frequency response, according to specific criteria. As a result, we find that the method of Bilinear (Tustin) approximation can be considered the best compared with other discretization methods.
Aleppo univ.Basic Science No71Modeling of a Boundary Value Problem with periodic mixed type of Boundary Conditions
The aim of this paper is to study the Eigenvalueproblems with periodic boundary conditions. Dealing with the variational formulation, we prove the existence of the Eigenvalues and eigenvectors corresponding to mechanical structure, which is fixed punctually. The asymptotic expansions is used to derive the first correction term and the homogenized eigenvalue problem corresponding to an entirely clamped structure. Keywords:Eigenvalueproblems,periodic boundary conditions, Boundary value problem ,Approximate solutions, homogenization theory,
R.J.of Aleppo University, Basic Science Series, No58Studying Mathematical model of Boundary Value problem to perturbed vibrations of silicon diaphragm in Mems capacitive Microphone
The traditional perturbation methods depend on a “small parameter” which is difficult to be determined for some real-applications .To overcome address this shortcoming, A new powerful semi-analytical method the Adomian decomposition method (ADM) is introduced to approximate the deflection of polysilicon diaphragm with small flexural rigidity of Micro Electro Mechanical System (MEMS) capacitive microphone. Using the theory of semigroup we prove the existence and the uniqueness of the solution of considered problem. Also, special attention to prove the convergence of the proposed method is given. Some numerical simulation and comparisons between the approximate solutions obtained by the application of the ADM with that obtained by the VIM are made to confirm the reliability and the accuracy of the applied method. The approximations obtained by ADM are uniformly valid not only for small parameters, but also for very large parameters.
R.J.of Aleppo University, Basic ScienceSeries No.74Comparative Study of Approximation Methods for Digital Filters Design Used in Damped Sinusoidal Wave Detection
This research is the first step in the design of digital filters used to detect a dumped sinusoidal signal. The effect of approximation methods on the obtained digital filter is evaluated. This evaluation is based on optimality criteria which were adopted and improved to distinguish the best response in the concerned application.
R.J.of Aleppo University, Basic SciencesNo71Homotopy Perturbation Method in Solving Nonlinear Boundary Value
In this paper, we present a modification to homotopy perturbation method for solving nonlinear Boundary value problems. Some examples are given, revealing its effectiveness and convenience. Also the results obtained by modified homopy perturbation method (MHPM) is superior to that obtained by the original homotopy perturbation method
World Applied Sciences Journal 37 (8): 695-699.Approximate Solution Corresponding To Periodically Heterogeneous Love-Kirchhoff Plate,
In this paper, we give a model of aLove-Kirshoff plate white periodic Cauchey Boundary conditions that means a mechanical structure in the linear elasticity theory, which is fixed punctually. We show that a mechanical frame which is fixed punctually has a behavior witch is near to the behavior of an entirely clamped structure. For this purpose we use a modified homogenization theory.And we give an estimation of the difference between the exact and approximate solution in regard to the number of fixation points.
World Applied Sciences Journal 37 (9): 742-745.Combine Kharrat-Toma Transform and Variational Iteration Method to Solve Nonlinear Boundary Value Problems
: In the present work, variational iteration method is combined with Kharrat-Toma transform methodto solve nonlinear problems. Some illustrative numerical examples are given. The solutions obtained by thismethod show the accuracy and the efficiency of the suggested combined method.
World Applied Sciences JournalNew Simple Spectrophotometric Method for the Simultaneous Estimation of the Mixtures of Sildenafil and some Serotonin Reuptake Inhibitors
This work presents a simple, reproducible, sensitive, generic, and efficient method for simultaneous estimation. Vierordt’s method or simultaneous equation method was developed and validated for simultaneous estimation of two mixtures: Sildenafil and Duloxetine, Sildenafil and Fluoxetine, in the pure and pharmaceutical dosage forms. The method was based on the measurement of absorbance at two wavelengths for each mixture in methanol. Calibration curves of all drugs were found to be linear. With good correlation coefficient values of more than 0.99. The RSD values were found within limits and the recoveries ranged between 98 to 102%, confirming that the proposed method is accurate. This method for the simultaneous estimation of these four mixtures is simple and economical and can be applied successfully for the simultaneous 4 estimation of PDEs inhibitors and their combinations with some serotonin reuptake inhibitors in the pure and pharmaceuticals dosage forms.
Research journal of pharmacy and technologySpectrophotometric Method for Simultaneous Estimation of Dapoxetine and some Phosphodiesterase-5 inhibitors in new combinations
ABSTRACT: This work presents a simple, reproducible, sensitive, generic االنكليزية/ العربية بالغة الملخص and efficient method for simultaneous estimation. Vierordt’s method or simultaneous equation method was developed and validated for simultaneous estimation of two mixtures: Tadalafil and Dapoxetine, Vardenafil and Dapoxetine, in the pure and pharmaceutical dosage form. The method was based on the measurement of absorbance at two wavelengths for each mixture in methanol. Calibration curves of all drugs were found. with a good correlation coefficient value of more than 0.99. The RSD values were found within limits and the recoveries ranged from 98 to 102% which confirms that the proposed method is accurate. This method for simultaneous estimation is simple, and economical and can be applied successfully for the simultaneous estimation of Dapoxetine and its combinations with Tadalafil and Vardenafil in pure and pharmaceuticals dosage forms.
Research journal of pharmacy and technology