oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 9 )

2019 ( 611 )

2018 ( 705 )

2017 ( 696 )

Custom range...

Search Results: 1 - 10 of 401279 matches for " M. Bouazara "
All listed articles are free for downloading (OA Articles)
Page 1 /401279
Display every page Item
Development of Analytical Model for Modular Tank Vehicle Carrying Liquid Cargo  [PDF]
M. Toumi, M. Bouazara, M. J. Richard
World Journal of Mechanics (WJM) , 2013, DOI: 10.4236/wjm.2013.32010
Abstract:

The study of dynamics of tank vehicles carrying liquid fuel cargo is complex. The forces and moments due to liquid sloshing create serious problems related to the instability of tank vehicles. In this paper, a complete analytical model of a modular tank vehicle has been developed. The model included all the vehicle systems and subsystems. Simulation results obtained using this model was compared with those obtained using the popular TruckSim software. The comparison proved the validity of the assumptions used in the analytical model and showed a good correlation under single or double lane change and turning manoeuvers.

Graph-Theoretic Approach for the Dynamic Simulation of Flexible Multibody Systems
M. J. Richard,M. Bouazara
Advances in Mechanical Engineering , 2012, DOI: 10.1155/2012/530132
Abstract: This paper provides a general description of a variational graph-theoretic formulation for simulation of flexible multibody systems (FMSs) which includes a brief review of linear graph principles required to formulate this algorithm. The system is represented by a linear graph, in which nodes represent reference frames on flexible bodies, and edges represent components that connect these frames. The method is based on a simplistic topological approach which casts the dynamic equations of motion into a symmetrical format. To generate the equations of motion with elastic deformations, the flexible bodies are discretized using two types of finite elements. The first is a 2 node 3D beam element based on Mindlin kinematics with quadratic rotation. This element is used to discretize unidirectional bodies such as links of flexible systems. The second consists of a triangular thin shell element based on the discrete Kirchhoff criterion and can be used to discretize bidirectional bodies such as high-speed lightweight manipulators, large high precision deployable space structures, and micro/nano-electromechanical systems (MEMSs). Two flexible systems are analyzed to illustrate the performance of this new variational graph-theoretic formulation and its ability to generate directly a set of motion equations for FMS without additional user input. 1. Introduction Stringent tolerances on mechanical components have created increasingly severe demands on the quality of new mechanical designs. The mathematical models used to simulate the various types of mechanical systems these days need to incorporate an optimization algorithm capable of predicting and improving the efficiency of an FMS design. Since the equations governing the motion of FMS are highly nonlinear and dynamically coupled, one must exploit some kind of linear graph principles [1–4] to properly define the interconnection between the bodies. By combining linear graph theory [5–8] with the principle of virtual [9–11] work and finite elements, a dynamic formulation is obtained that extends graph-theoretic (GT) modelling methods to the analysis of 3D beams and shell surfaces of FMS. The widespread interest in flexible multibody systems is evidenced by the existence of a large number of algorithms [12]. It has been shown [13–15] that for multibody systems, a graph-theoretic formulation can generate a minimal set of equations. GT-based approaches explicitly separate the linear topological equations for the entire system from the nonlinear constitutive equations for individual components, resulting in very
Static and Vibration Analysis of an Aluminium and Steel Bus Frame  [PDF]
Fatma Reba?ne, Mohamed Bouazara, Ahmed Rahem, Lyne St-Georges
World Journal of Mechanics (WJM) , 2018, DOI: 10.4236/wjm.2018.84010
Abstract: The transport sector is increasing day by day to satisfy the global market requirement. The bus is still the main mode of intercity transportation in Canada. Despite, an essentially unchanged conception, the total weight of the bus has increased by over 25% during the last three decades. To solve this problem, industrialists have moved to the use of light metals in the transportation field. Therefore, use of lightweight materials, such as aluminum is essential to reduce the total weight of bus. In this study, the focus is on the bus frame as it represents 30% of the total weight and it is the most stressed part of the bus. Its life duration is more important compared to that of all other elements. Thus, a study of the static and vibratory behavior would be very decisive. In this article, two types of analysis are carried out. First is the modal analysis to determine the natural frequencies and the mode shapes using a developed dynamic model of the bus. Because if any of the excitation frequencies coincides with the natural frequencies of the bus frame, then resonance phenomenon occurs. This may lead to excessive deflection, high stress concentration, fatigue of the structure and vehicle discomfort. In this case, the results analysis shows that the natural frequencies are not affected by the change of material. The second type of analysis is the linear static stress analysis to consider the stress distribution and deformation frame pattern under static loads numerically. For the numerical method, the frame is designed using SolidWorks and the analysis is made using Ansys WorkBench. The maximum Von Mises stress obtained for the static loading is in the same order for the three chassis frames studied. But in the case of the aluminium frame, the weight of 764 kg was reduced.
Study of Duct Characteristics Deduced from Low Latitude Ground Observations of Day-Time Whistler at Jammu  [PDF]
M. Altaf, M. M. Ahmad
International Journal of Astronomy and Astrophysics (IJAA) , 2013, DOI: 10.4236/ijaa.2013.33032
Abstract:

Propagation characteristics of low latitude whistler duct characteristics have been investigated based on day-time measurements at Jammu. The morphogical characteristics of low latitude whistlers are discussed and compared with characteristics of middle and high latitude whistlers. The Max. electron density (Nm) at the height of the ionosphere obtained from whistler dispersion comes out to be higher than that of the background which is in accordance with the characteristics of whistler duct. The equivalent width is found to be close to the satellite observations and the characteristics of whistler duct in low latitude ionosphere are similar to those in middle and high latitude ionosphere. The width of ducts estimated from the diffuseness of the whistler track observed during magnetic storm is found to lie in the range of 50 - 200 Km.

Review Article: Immobilized Molecules Using Biomaterials and Nanobiotechnology  [PDF]
Magdy M. M. Elnashar
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2010, DOI: 10.4236/jbnb.2010.11008
Abstract: Immobilized molecules using biomaterials and nanobiotechnology is a very interesting topic that touching almost all aspects of our life. It uses the sciences of biology, chemistry, physics, materials engineering and computer science to develop instruments and products that are at the cutting edge of some of today’s most promising scientific frontiers. In this review article, the author based on his experience in this arena has tried to focus on some of the supports for im-mobilization; the most important molecules to be immobilized such as DNA, cells, enzymes, metals, polysaccharides, etc and their applications in medicine, food, drug, water treatment, energy and even in aerospace. He specified a special section on what is new in the arena of supports and technologies used in enzyme immobilization and finally a recommendation by the author for future work with a special attention to up-to-date references.
Using of the generalized special relativity (GSR) in estimating the neutrino masses to explain the conversion of electron neutrinos  [PDF]
M. H. M. Hilo
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.34044
Abstract: In this work the Generalized Special Relativity (GSR) is utilized to estimate masses of some elementary particles such as, neutrinos. These results are found to be in conformity with experimental and theoretical data. The results obtained may explain some physical phenomena, such as, conversion of neutrinos from type to type when solar neutrino reaches the Earth.
Postischemic Lower Extremity Wounds Treated with and without Negative Pressure Dressing  [PDF]
Naz?mmü?
Surgical Science (SS) , 2012, DOI: 10.4236/ss.2012.37075
Abstract: Background: Vacuum-assisted dressing is a noninvasive closure system of the wound, which makes localized and controlled negative pressure. Its mechanical tension reduces edema, stimulates granulation tissue formation and angiogenesis, and prepares the wound bed for closure. In this study, a patient has been presented, who suffered from serious lower extremity wounds due to arterial emboli, one of her wounds has been treated with vacuum-assisted dressing and the other with conventional dressing to evaluate the efficacy of vacuum-assisted dressing in acute ischemic wounds. Methods: A 65-year-old female patient was admitted to the emergency clinic, due to complaint of severe pain in her right lower extremity which suggested an acute arterial occlusion. She immediately underwent an embolectomy operation; however, a few days later, severe ischemia on the leg and foot became appearant. All of the necrosis was sharply debrided under sterile conditions in the operating room, and then lower leg wound was covered with vacuum-assisted dressing, also calcaneal wound was dressed with silver sulphadiazine. Results: Eighteen days after the first dressing with negative pressure, distal leg wound became ready for closure, whereas, enough granulation tissue over the calcaneal area developed merely thirty-four days later. Calcaneal wound closed spontaneously within fifty-three days. Conclusions: When dealing with this experience, using the negative pressure dressing in patient with severe lower limb wounds following arterial emboli, accelerates wound healing by means of developing the granulation tissue, and rapidly prepares the wound for closure, so it may reduce the risk of amputation.
Laplace Transform Method for Unsteady Thin Film Flow of a Second Grade Fluid through a Porous Medium  [PDF]
M. Ali, M. Awais
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.53017
Abstract:

In this article, we have effectively used the Numerical Inversion of Laplace transform to study the time-dependent thin film flow of a second grade fluid flowing down an inclined plane through a porous medium. The solution to the governing equation is obtained by using the standard Laplace transform. However, to transform the obtained solutions from Laplace space back to the original space, we have used the Numerical Inversion of Laplace transform. Graphical results have been presented to show the effects of different parameters involved and to show how the fluid flow evolves with time.

An Integral Collocation Approach Based on Legendre Polynomials for Solving Riccati, Logistic and Delay Differential Equations  [PDF]
M. M. Khader, A. M. S. Mahdy, M. M. Shehata
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.515228
Abstract:

In this paper, we propose and analyze some schemes of the integral collocation formulation based on Legendre polynomials. We implement these formulae to solve numerically Riccati, Logistic and delay differential equations with variable coefficients. The properties of the Legendre polynomials are used to reduce the proposed problems to the solution of non-linear system of algebraic equations using Newton iteration method. We give numerical results to satisfy the accuracy and the applicability of the proposed schemes.

ДОСЛ ДЖЕННЯ АНАЛ ТИЧНОГО МЕТОДУ ОЦ НЮВАННЯ ЙМОВ РНОСТ ПОТЕНЦ ЙНО КОНФЛ КТНИХ СИТУАЦ Й В ПОВ ТРЯНОМУ РУС The study of the analytical method of evaluating the probability of potential conflict situations in air traffic Исследование аналитического метода оценки вероятности потенциально конфликтных ситуаций в воздушном движении
В.M. Василь?в
Proceedings of National Aviation University , 2007,
Abstract: Розглянуто застосування запропонованого ран ше методу оц нювання ймов рност потенц йних конфл кт в для системи керування пов тряним рухом. Досл джено властивост методу, наведено проанал зовано результати комп’ютерного моделювання. Application of the method of potential conflicts probability evaluation offered before for air traffic control system is considered. The properties of the method are investigated, results of computer modeling are represented and analyzed. Рассмотрено применение предложенного ранее метода оценки вероятности потенциальных конфликтов для системы управления воздушным движением. Исследованы свойства метода, приведены и проанализированы результаты компьютерного моделирования.
Page 1 /401279
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.