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Indian Journal of Pure and Applied Physics

 

 ISSN: 0019-5596

              

CODEN:IJOPAU 41(12) 901-1001(2003)

VOLUME 41                                          

NUMBER 12   

DECEMBER   2003

 

CONTENTS

General

Ground state properties of BECs of 87Rb atoms in an isotropic magnetic trap for different total number of atoms

S P Tewari*, Poonam Silotia & Aditya Saxena

 

 


905

Nuclear Physics

Importance of hexadecapole interactions in even-even germanium and selenium isotopes

Tariq Ahmad War, Anil Chandan, Rani Devi, S K Khosa* & Arun Bharti

 

914

Atomic and Molecular Physics

Second-order polarizabilities of some quinolines

Gunjan Purohit* & G C Joshi

 

922

Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics and Fluid Dynamics

Volumetric and viscometric studies on N,N-dimethylacetamide+1-hexanol/1-heptanol binary liquid mixtures at different temperatures

Anwar Ali*, Anil Kumar Nain, Dinesh Chand & Bhajan Lal

 


928

Numerical solution of free convection flow of a micro-polar fluid past a porous vertical plate

Atul Kumar Singh

936

 

 

Condensed Matter: Structural, Mechanical and Thermal Properties

Extensivity of entropy

K Das* & S Sengupta



941

Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties

Higher-order squeezing in Raman scattering

Dilip Kumar Giri* & P S Gupta


946

Electronic transport in one-dimensional systems

M P Singh & C M Bhandari*

950

ESR, optical absorption and transport studies of Cu2+ in 50 Li2O3-(50-x) B2O3-xBi2O3 glass system

S Suresh Swapna & V Chandramouli

954

Fast ion transport in P (VDF-HFP)-PMMA-PC-LiClO4-TiO2 composite gel polymer electrolytes

D Saikia & A Kumar*

961

Interdisciplinary Physics and Related Areas of Science and Technology

High input impedance HP, BP and LP filters using FTFNs

N A Shah* & M A Malik

 

967

Geophysics, Astronomy and Astrophysics

Doppler technique for detection of victims buried under earthquake rubble

P K Banerjee* & A Sengupta

 

970

   
Annual Index

975

____________

*The corresponding author has been indicated by (*) mark in case of papers with more than one author

 

 

 

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 905-913

 

Ground state properties of BECs of 87Rb atoms in an isotropic magnetic trap for different total number of atoms*

S P Tewari, Poonam Silotia & Aditya Saxena

 

Ginzburg-Pitaevskii Gross (GPG) non-linear equation for the Bose Einstein Condensate (BEC) having different number of 87Rb atoms (in the range 102 to 5×106) in an isotropic magnetic trap, has been numerically solved to obtain its eigenvalue, the chemical potential, and the corresponding wave function, to study its various observable physical properties, such as, the correlation length, healing length, inter-particle separation in the core and the speed of sound in the condensate. These have been compared with the corresponding results computed by using the approximate expression obtained in the limiting case when the number of atoms in the condensate tends to a large value, that is, in the Thomas-Fermi approximation. Significance and inter-relationships of various physical quantities have also been discussed in the light of recent experimental results.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 914-921

 

Importance of hexadecapole interactions in
even-even germanium and selenium isotopes

Tariq Ahmad War, Anil Chandan, Rani Devi, S K Khosa & Arun Bharti

 

Variation after projection (VAP) calculations in conjunction with Hartree-Bogoliubov (HB) ansatz have been carried out for germanium and selenium isotopes. In this framework, the yrast spectra with JП £ 10+, B(E2) transition probabilities, quadrupole deformation parameter (b2) have been obtained. The results of the calculation give an indication that, it is important to include the hexadecapole-hexadecapole component of the two-body interaction for obtaining various nuclear structure quantities in Ge and Se isotopes. Besides this, it is important to include 2d5/2 orbit in valence space for making nuclear structure calculations in Ge–Se mass region.

 

  

 

Indian J Pure & Applied Physics

Vol. 41, December 2003, pp. 922-927

 
Second-order polarizabilities of some quinolines

Gunjan Purohit* & G C Joshi

 

Second order polarizabilities (b) of some quinolines viz. 8-hydroxyquinoline (8-HQ), 8-aminoquinoline (8-AQ) and 8-hydroxyquinolidine (8-HQD) have been experimentally determined by solvatochromic technique using two-level quantum mechanical model. Comparison has been made with other useful organic molecules and the role of hydrogen bonding has been discussed.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 928-935

 

Volumetric and viscometric studies on
N,N-dimethylacatamide + 1-hexanol/1-heptanol
binary liquid mixtures at different temperature
s

Anwar Ali, Anil Kumar Nain, Dinesh Chand & Bhajan Lal

 

Densities r, and viscosities h, have been measured for pure N,N-dimethylacetamide (DMA), 1-hexanol, 1-heptanol and for their 18 binary mixtures with DMA as a common component, covering the entire composition range, at 25, 30, 35, 40 and 45 °C. Using the experimental values of r and h, the excess molar volume VE, excess viscosity hE, excess rheochore [RE], excess partial molar volume`V2°E, of alkanols in DMA at infinite dilution and excess free energy of activation of viscous flow DG*E, have been calculated. The dependence of these excess functions on composition and temperature has been discussed from the point of view of inter-molecular interactions in these mixtures. Furthermore, from the temperature dependence of viscosity, the enthalpy DH*, and entropy DS*, of activation of viscous flow have also been calculated and their dependence on composition have been discussed.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 936-940

 

Numerical solution of free convection flow of a
micro-polar fluid past a porous vertical plate

Atul Kumar Singh

 

An implicit finite difference method is applied to obtain the numerical solution of free convection flow of an incompressible micro-polar fluid past an infinite vertical porous plate taking into account transpiration effect. The effects of material constants, transpiration parameter and Prandtl number are observed on velocity field and skin-friction. In addition, the effects of material constants and Prandtl number are also observed on micro-rotation of the micro-polar fluid.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 941-945

 

Extensivity of entropy

S K Das and S Sengupta

 

In the conventional framework of thermodynamics it is an established fact that, in absence of surface effects, infinitesimal change in entropy is extensive. But this does not automatically guarantee the extensivity of entropy. Our purpose in this paper is to discuss this problem, strictly within the framework of thermodynamics, using a principle of linear superposition in conjunction with a simple postulate, which contains a feature consistent with quantum mechanical concept of indistinguishability of atoms and molecules. Some important consequences of the extensivity of entropy are also discussed. Extensivity of entropy is essential to calculate the change in entropy in an adiabatic irreversible process where the number of atoms of a system is not fixed as well as to make thermodynamics free from the well-known Gibbs paradox.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 946-949

 

Higher-order squeezing in Raman scattering

Dilip Kumar Giri & P S Gupta

 

The occurrence of fourth and fifth-order squeezing in the fundamental mode of the electromagnetic field in spontaneous Raman process under the short-time approximation is investigated based on a fully quantum mechanical approach. The coupled Heisenberg equations of motion involving real and imaginary parts of the quadrature operators are established. The dependence of the higher-order squeezing on the number of photons is investigated. It is shown that higher-order squeezing allows a much larger fractional noise reduction.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 950-953

 

Electronic transport in one-dimensional systems

*M P Singh & C M Bhandari

 

Electronic thermal transport and electrical transport in quasi one-dimensional structures is the subject matter of present communication. Expressions have been obtained for electronic thermal conductivity, electrical conductivity and Lorenz factor. Results of calculation for polycrystalline bismuth telluride have been presented at 300 K for different carrier densities and wire diameters. It is concluded that, cross-sectional size of the wire influences the Lorenz factor in carrier density range 1023-1026 m–3. Effect of cross-sectional size on electrical conductivity and electronic thermal conductivity is appreciable at carrier densities above 1023 m–3.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 954-960

 

ESR, optical absorption and transport studies of
Cu2+ in 50Li2O3-(50-x)B2O3-xBi2O3 glass system

S Suresh Swapna & V Chandramouli

 

The preparation and studies on the spectroscopic and transport properties of lithium boro bismuthate glasses are reported. From IR results, it is observed that at low concentrations, Bi2O3 (less than 30 mol %) in the glass acts as glass modifier thereby, increasing non-bridging oxygen ions. At higher concentrations, it enters into the network. The structure of the resulting glass consists of (BiO3+BO3) units. The hyperfine splitting in the parallel feature of ESR spectra of Cu2+ in the glass is detectable at low concentration of Bi2O3, which, however, diminishes at higher concentration of Bi2O3.The ionic conductivity results indicate that, the conductivity is due to the mobile lithium ions and log (electrical conductivity)                                                                      found to increase with the concentration of bismuth oxide and passes through a maximum at 30 mol % of Bi2O3 indicating a mixed glass former effect.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 961-966

 

Fast ion transport in P(VDF-HFP)-PMMA-PC-LiClO4-TiO2
composite gel polymer electrolytes

D Saikia & A Kumar

 

Thin films of poly (vinylidene fluoride-co-hexafluoropropylene) P(VDF-HFP) and poly (methylmethacrylate) PMMA polymer blend electrolytes plasticized with propylene carbonate (PC) and LiClO4 as salt and TiO2 as inorganic filler have been prepared by solution casting technique. Films of thickness in the range of 30 mm – 1 mm prepared by varying the plasticizer-filler and salt-filler ratio were characterized by ac impedance measurements in the temperature range 293-373 K. Addition of ceramic filler to the polymer electrolyte was found to result in an enhancement of the ionic conductivity. A maximum electrical conductivity of ~2.81×10-2 S/cm at 293 K and ~4.5´10-2 S/cm at 373 K has been achieved with the dispersion of the TiO2. Transport number measured by Wagner’s polarization method, using silver blocking electrodes, was found to be 0.985. FTIR spectral studies confirmed the formation of polymer-salt complex. XRD patterns exhibit the increased amorphicity in the blended composite gel polymer electrolytes.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 967-969

 

High input impedance HP, BP and LP filters using FTFNs

N A Shah & M A Malik

 

The paper presents a new multifunction filter based on and employing four terminal floating nullors(FTFNs) which simultaneously realizes bandpass (BP) and lowpass (LP) filtering functions. The circuit can be made to realize highpass (HP) and bandpass (BP) filtering signals as well by changing one admittance and exhibits high input impedance thus, facilitating cascading of such circuits to realize higher order filters. The circuit employs grounded capacitors which suits contemporary IC design techniques and has the distinct feature of providing controllable gain of all the filtering functions through grounded passive components. Besides enjoying low passive sensitivity figures, the resonance frequency w0 and bandwidth w0 /Q are independently tunable in a sequential manner. PSPICE simulation results are also included.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, December 2003, pp. 970-974

 

Doppler technique for detection of
victims buried under earthquake rubble

P K Banerjee1 & A Sengupta2

 

Design and development of an electronic remote victim locator* is described in this paper. It has been designed for locating remotely, any animate subject buried under rubble or behind a barrier. It works on the principle of Doppler effect at microwave frequencies. Electromagnetic signal travels down the debris from a transmit/receive antenna, illuminates the animate subject under the rubble and returns to the top of the debris having phase modulated with body movements. The antenna picks up the phase-modulated signal, which is processed by a microwave phase synchronous receiver. The detected signal is displayed on an oscilloscope or any other suitable display device. The display is either a regular breathing cycle or any sudden shift in its steady level, resulting from even a slight movement of any part of the body. An important part of the system is the clutter (unwanted reflections) canceller. Presently, the system can penetrate a dry concrete debris depth of about 2 m. Detection depth may be greater if there are more air voids in the debris. Efforts are on to improve the depth of penetration in the rubble. The same system can detect presence of any person behind a barrier, which has security applications.