Mediterranean Journal of Modeling and Simulation

Number 4, 2015

9
Reduction of hot points formation in a heat tube bundle exchanger

Authors: Youcef Kamla, Mohamed Bouzit, Djamel Sahel, Warda Boudaoud, Abdelkader Karas

Abstract

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Among the major problems in the use of baffles in heat exchangers is the formation of hot points due to the stagnation of the flow behind baffles. The present work shows a design of a porous space in the baffles in order to shake the dead zones behind these baffles. The numerical investigation is based on the Navier Stocks averaged (RANS) using FLUENT software. The results validated by experimental data from the literature shows that the porous space presented in this paper reduces in an observable manner the hot points and increase the heat transfer rate.

13
New exact bound states solutions for (C.F.P.S.) potential in the case of Non commutative three dimensional non relativistic quantum mechanics

Authors: Abdelmadjid MAIRECHE

Abstract

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We obtain here the modified bound-states solutions for central fraction power singular potential (C.F.P.S.) in noncommutative 3-dimensional non relativistic quantum mechanics (NC-3D NRQM). It has been observed that the commutative energy spectra was changed, and replaced degenerate new states, depending on four quantum numbers: j, l and sz=±1/2 corresponding to the two spins states of electron by (up and down) and the deformed Hamiltonian formed by two new operators: the first describes the spin-orbit interaction , while the second obtained Hamiltonian describes the modified Zeeman effect (containing ordinary Zeeman effect) in addition to the usual commutative Hamiltonian. We showed that the isotropic commutative Hamiltonian HCFPS will be in non commutative space anisotropic Hamiltonian HNC-CFPS.

14
Electromagnetic characterization and modelling of superconducting material

Authors: Bruno Douine, Jean Lévêque

Abstract

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Number of views: 366

Electromagnetic characterization and modelling of superconducting material are very important for end users. Firstly main features of superconducting material are presented. Secondly two methods of characterization to obtain experimentally the influence of magnetic field on critical current density JC are presented. These two methods are commonly used for applications in electrical engineering. The electrical method is based on measuring the voltage and current of a superconducting sample. It has the advantage of simplicity in implementation, but the main drawback as the presence of the self magnetic field. This prevents the determination of the parameters of JC(B) for weak magnetic fields. The magnetic method using the cycle of magnetization has the advantage of making measurements without contact with the sample but has two drawbacks: it is based on a theoretical model in which JC is constant and the assumption of infinite length sample.

14
Fatigue Life Prediction of Package of Suspension Automotive Under Random Vibration Based on Road Roughness

Authors: Kazem Reza Kashyzadeh, Mohammad Jafar Ostad-Ahmad-Ghorabi, and Alireza Arghavan

Abstract

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Number of views: 418

The impact of a suitable suspension system for passenger comfort and vehicle steering is an obvious order and direct impact on the safety of passengers must be considered, to do so different kinds of tests must be exerted, one of these is fatigue testing which is one of the most significant ones. Another issue is the high cost in practical ways, and to cope with this issue various ways must be assessed and analyzed, one of the best and the most efficient ways is modelling and testing in virtual software environments. In the present paper, predict fatigue life of suspension component and package of automotive suspension are the main purposes. First, using MATLAB software, road roughness according to the intercity roads for constant vehicle velocity (100 Km/h) has been studied. After that frequency response of components has been analysed, its critical points determined to calculate the fatigue life of the part, and the amount of critical stress obtained based on Von Misses, Tresca and Max Principle criterion for a quarter car model (passive suspension System in 206 Peugeot). Fatigue life of the vehicle components are calculated in terms of kilo-Meters in specialized fatigue software such as 116944, 92638.9, 46388.9 and 191388.9 Km respectively wheel hub, pitman arm, suspension arm and package of suspension. Finally, to prove the given results of the finite element method compared with reported results by other researchers and the results match very well with those.

22
Product of Likelihood Ratio Scores Fusion of Dynamic Face, Text Independent Speech and On-line Signature Based Biometrics Verification Application Systems

Authors: Mohamed SOLTANE

Abstract

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Number of views: 396

In this paper, the use of finite Gaussian mixture modal (GMM) tuned using Expectation Maximization (EM) estimating algorithms for score level data fusion is proposed. Automated biometric systems for human identification measure a “signature” of the human body, compare the resulting characteristic to a database, and render an application dependent decision. These biometric systems for personal authentication and identification are based upon physiological or behavioral features which are typically distinctive, Multi-biometric systems, which consolidate information from multiple biometric sources, are gaining popularity because they are able to overcome limitations such as non-universality, noisy sensor data, large intra-user variations and susceptibility to spoof attacks that are commonly encountered in mono modal biometric systems. Simulation result show that finite mixture modal (GMM) is quite effective in modelling the genuine and impostor score densities, fusion based the product of Likelihood Ratio achieves a significant performance on eNTERFACE 2005 multi-biometric database based on dynamic face, on-line signature and text independent speech modalities.