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International Review of PHYSICS - February 2008 - Papers

A Simple General Solution of the Radial Schrödinger Equation for Spherically Symmetric Potentials and Some Applications Overview of the ATLAS TileCal High Voltage DCS Effects of Atom-light Interaction Parameters on the Photonic Mean Numbers and Atomic Level Populations in the Interaction of Three Level Atoms with Classical and Coherent Fields Vortex Flow and Frequency Mode Inside Different Cavities Interacting with Boundary Layer Materials Developed by Mechanical Alloying and Melt Spinning Finite Element Method Analysis of The Behaviour of A Multilayered Screen Polarizer Crystalline Silicon Solar Cell on Ceramic Substrates Under Solar Concentration Transitions in S XI, Cl XII, and Ar XIII ESR Dating of Laterite from Muang Sing Historical Park, Kanchanaburi, Thailand Finite Element Method for the Prediction of Magnetic Fields and Losses in Three Phase Underground SF6 Insulated Cables

    A Simple General Solution of the Radial Schrödinger Equation for Spherically Symmetric Potentials and Some Applications
        by H. H. Erbil

Abstract - A simple procedure for the general solution of the radial Schrödinger equation has been found for spherical symmetric potentials without making any approximation. The wave functions are always periodic. Two difficulties may be encountered: one is to solve the equation E = U(r), where E and U(r) are the total and effective potential energies, respectively, and the other is to calculate the integral . If these calculations cannot be made analytically, it should then be performed by numerical methods. To find the energy of the ground state, there is no need to calculate this integral, it is sufficient to find the classical turning points, that is to solve the equation E = U(r). By using this simple procedure, the radial Schrödinger equation for a particle in an infinitely high central effective potential well of any form was solved without making any approximation. Two different solutions were obtained, namely, symmetric and antisymmetric. These functions are damped periodic functions. By using this simple method, the radial Schrödinger equation in the spherical coordinates was also solved for a free particle without making any approximation. The simple wave functions those are not dependent on the spherical Bessel and Neumann functions were obtained.

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Keywords: Free particle, infinitely high potential wells, radial equation, shell model, spherical symmetric potential.

    Overview of the ATLAS TileCal High Voltage DCS
         by A. Elkharrim

Abstract - ATLAS (A Toroidal LHC ApparatuS) is one of the experiments at the Large Hadron Collider (LHC) at CERN planned to be operational by the end of the year 2008. The main goal of the experiment is the discovery of the Higgs boson, the missing piece in the Standard Model (SM) of Particle Physics and to explore physics beyond the SM. This paper is intended to give a short survey of the high voltage Detector Control System supported by the ATLAS Tile Hadron Calorimeter group at CERN.

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Keywords: ATLAS, CERN, TileCal, High Voltage DCS, DIM.

    Effects of Atom-light Interaction Parameters on the Photonic Mean Numbers and Atomic Level Populations in the Interaction of Three Level Atoms with Classical and Coherent Fields
         by B. Vaseghi, M. M. Golshan, A. Fallah Zadeh

Abstract - In this paper, the phenomenon of collapse and revival in the interaction of three-level atoms (Λ-configurtion) with two electromagnetic fields is studied .We investigate the interaction when one of the fields is quantum mechanically coherent and the other is classical. The atoms are initially assumed to be in their ground states or in a maximal atomic coherency. For each case ,the mean photon numbers and atomic level populations are calculated. From plots of these quantities, as functions of time and for different values of atom – light interaction parameters, the following results are deduced. (1)In all cases the phenomenon of collapse and revival in the photonic mean number and atomic level populations occur. (2)As the atomic system is initially in a coherent superposition of the two lower states , the mean photon number ,while depending on relative phase of the induced transition dipole moments, is enhanced. The atomic level populations would also depend upon this relative phase.
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Keywords: Collapse And Revival; 3-Level Atom; Coherent Fields.

    Vortex Flow and Frequency Mode Inside Different Cavities Interacting with Boundary Layer
         by H. Khouloud, M. Bouterra, A. El Cafsi, A. Belghith, F. Lusseyran, P. Gougat

Abstract - A number of studies have referred to the existence of a vortex cell within an urban street canyon. The understanding of vortex dynamics or vorticity distribution is a such configuration is of great interest. This configuration was simulated by the interaction between a boundary layer and a cavity. Experimental characterization of the vortex structures evolution was developed by the technique of measure Particle Image Velocimetry (PIV). In this paper, we have studied and characterized experimentally by the technique of measure Laser Doppler Velocimetry (LDV) the vortex escape frequencies. Measurements were performed for different cavity shape ratio and for different mean velocities. Where the ratio between the shear instability process and the mechanisms of frequency selection which depend of the size of the cavity.
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Keywords: Cavity, Vortex structures, Frequency Mode, spectral Analysis, shape ratio..

    Materials Developed by Mechanical Alloying and Melt Spinning
        by J. J. Suñol, J. J. Fort

Abstract - Materials science is a multidisciplinary research topic related to the development of physics and technology. Mechanical alloying of ribbon flakes is a two steps route to develop advanced materials. In this work, a Fe based alloy was obtained using three pathways: mechanical alloying, melt-spinning and mechanical alloying of previously melt-spun samples. Processing conditions allow us to obtain amorphous or nanocrystalline structures. Furthermore, a bibliographic revision of mechanical alloying is here presented.

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Keywords: Mechanical alloying, Fe based alloys, XRD, DSC.

  Finite Element Method Analysis of The Behaviour of A Multilayered Screen Polarizer²
        by M. Lascu

Abstract - The paper presents the spectral domain analysis of printed radiating structures. These structures include microstrip antenna elements, printed array antenna, and printed screen polarizer. The paper is focused on the screen polarizer. The screen polarizer is an important application of a multilayered structure. The analysis of a screen polarizer is very straightforward. For normal incident fields, a polarizer is electrically equivalent to parallel waveguides. The orientation of a waveguide depends on the direction of the polarization vector. The equivalent circuit of a typical polarizer is shown. In the equivalent circuit, a strip screen is equivalent to a lumped susceptance. In this paper are the formulations for this lumped susceptance, including the effects of the adjacent dielectric media presented. A finite element analysis of multilayered screen polarizer is outlined. Finally, electrical performance of a twolayered polarizer is shown.

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Keywords: Finite Element Method, Lumped Susceptance, Multilayered Screen Polarizer, Polarization vector.

   Crystalline Silicon Solar Cell on Ceramic Substrates Under Solar Concentration
        by A. Cheknane, A. Chaker, B. Benyoucef, H. S. Hilal

Abstract - SiC-based and Al2O3-based Si solar cells, together with a single p-n (Si) homo-junction solar cell, have been investigated. Open-circuit voltage, short circuit current and cell efficiency for each solar cell have been measured, under different solar concentrations. The parameters for all cells were improved with higher concentration levels. The open circuit voltage reached a maximum value under 500 sun concentration for each cell. Efficiency values of 31.4%, 27.5% and 20% for the SiC-based cell, Al2O3-based cell and the homo-junction cell, respectively, have been obtained, when appropriate cooling systems were used. Such difference is presumably due to the more efficient cooling mechanism of the substrates, being more efficient for SiC. This characteristic, together with cost considerations and mechanical properties, makes the SiC substrate a good candidate to support Si thin film solar cells..

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Keywords:  Solar cell, ceramic, Al2O3, SiC, efficiency, solar concentration.

    Transitions in S XI, Cl XII, and Ar XIII
        by W. O. Younis

Abstract - Energy levels, oscillator strengths and transitions probabilities for transitions among the fine-structure levels of the terms belonging to the 2s²2p², 2s²2p3l, 2s²2p4l (l= 0-2), 2s²2p5s configurations. The calculations are based upon the general configuration interaction code CIV3 of Hibbert which uses orthonormal orbitals of radial functions expressed as superposition of normalized Slater-type orbitals (STOs). Calculated values are compared with experimental and other theoretical results where a satisfactory agreement is found. Moreover some unpublished energy values and oscillator strengths are reported.

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Keywords: Atomic data.

   ESR Dating of Laterite from Muang Sing Historical Park, Kanchanaburi, Thailand
        by Supanee Limsuwan, Tidarut Vichaidid, Wandee Onreabroy

Abstract - Electron spin resonance (ESR) spectroscopy technique has been employed to date the laterites collected from Muang Sing historical park, Kanchanaburi province (175 kilometers from Bangkok). The dose response of the ESR signals were found to be suitable for an age determination using a signal at g = 2.0028.  The ESR signal growth curve on additional g irradiation has been best fitted by an exponential saturation function. Based on this model, the accumulated dose (AD) value for dating is obtained. The annual dose rate (D) was calculated from the contents of ²³⁸U, ²³²Th and ⁴⁰K in the sample by nuclear activation analysis (NAA). In addition, the dose rate of cosmic rays as the dose rate corrections was determined.  The ESR age of the laterites was found to be 5.45 ± 0.58 ka. The results show that the ESR age falls into the Holocene epoch of the geological time scale.

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Keywords: Muang Sing historical park, ESR dating, Laterite.

    Finite Element Method for the Prediction of Magnetic Fields and Losses in Three Phase Underground SF6 Insulated Cables

        by S. Sadeghi, M. Jalalifar, A. H. Isfahani

Abstract - This paper presents a finite element method for predicting magnetic field above ground, generated by an underground SF6 insulated cable as well as its eddy current losses. First, with the aid of Ansys software the magnetic field in underground SF6 insulated high voltage cables under and above ground is computed and then, currents and losses in the shields of the cables are computed. The influences of the operating parameters on these quantities are also examined.

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Keywords: SF6 insulated cables, Magnetic field, Losses, Finite element method.