Indian Journal of Pure and Applied Physics

 

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VOLUME 40                                                      NUMBER 4                                                        APRIL  2002

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CONTENTS

 

The Physics of Elementary Particles and Fields

Gluon distribution at moderately low-x from NMC deuteron structure function data

     J K Sarma* & G A Ahmed

 

235

Nulcear Physics

Radiation activity and exhalation rates in coal fired thermal power plants

      R P Chauhan* & S K Chakarvarti

 

242

Atomic & Molecular Physics

Quantum chemical study of vibrational spectra and thermodynamic properties of 2-butanone conformers

      Archana Sharma, V P Gupta* & Ajit Virdi

 

246

Spectral and normal coordinate analysis of 6-methoxy purine

      V Krishna Kumar* & R Ramasamy

252

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

Ultrasonic investigations of X…HO bond complexes

      Madhu Rastogi, Aashees Awasthi, Manisha Gupta & J P Shukla*

 

 

256

Molecular interactions in binary liquid mixtures – An ultrasonic study

      P Subramanyam Naidu & K Ravindra Prasad*

264

Condensed Matter: Structure, Mechanical and Thermal Properties

EXAFS study of Sr doped Y0.4Pr0.6Ba2Cu3O7-d

      T S Anvekar, K R Priolkar, V G Sathe, A V Pimpale* P R Sarode & V N Kamat Dalal

 

272

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

Structural and electrical behaviour of Pb(Mn1/4Cu1/4Mo1/4)O3 ceramics

      S K Sinha, S N Choudhary & R NP Choudhary*

 

277

Thermomagnetic behaviour of Gd substituted ferrite magnetic fluids

      Trupti Upadhyay* & Kinnari Parekh

282

Effect of strontium impurity ions on conductivity of KBr:Sr

      G Saibabu, N Vasanth Kumar, C Suresh Reddy*

290

Band gaps of nanocomposites

      G P Joshi, R Mangal, N S Saxena* & T P Sharma

297

Structure, conductivity and magnetic study of Sr2Zn2Al2Fe10O22 ferrite

      M Y Salunkhe, N Y Lanje & D K Kulkarni*

301

News Scan

Bose-Einstein condensate-A new state of matter

      Tarun Banerjee

 

304

____________

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

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 40, April  2002, pp. 235-241

Gluon distribution at moderately low-x from NMC deuteron

structure function data

J K Sarma1 & G A Ahmed2

Physics Department, Tezpur University, Napaam, Tejpur 784 028

Received 17 April 2001, accepted 2 August 2001

The authors present some simple methods to find gluon distribution from analysis of deuteron F2 structure function data at moderately low-x. Here, they use the leading order (LO) Altarelli-Parisi (AP) evolution equation and New Muon Collaboration (NMC) deuteron F2 structure function data to extract gluon distribution. They also compare their results with those of other authors.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 242-245

Radon activity and exhalation rates in coal fired thermal power plants

R P Chauhan & S K Chakarvarti*

Department of Physics, IGN College, Ladwa, Kurukshetra 136 132

*Department of Applied Physics, Regional Engineering College, Kurukshetra, India 136 119

(E-mail: chauhanrp@hotmail.com; chauhanrp1@rediffmail.com)

Received 19 December 2001; accepted 11 February 2002

The combustion of coal in various thermal power plants results in the release of some natural radioactivity to the atmosphere through formation of flyash and bottom ash or slag. This consequently increases the radioactivity in soil, water and atmosphere around thermal power plants. As the radon in the atmosphere (indoor and outdoor), soil, ground water, oil and gas deposits contributes the largest fraction of the natural radiation dose to populations, enhanced interest exhibited in tracking its concentration is thus fundamental for radiation protection, health and hygiene point of view. In the present study, measurements of radon emanation from coal, flyash, soil and water samples collected from five thermal power plants of north India have been made using SSNTDs. The average values of radon emanation at equilibrium in the air volume of Cans above different samples varied from 433 ± 28 Bq m–3 to 2086 ± 36 Bq m–3; mass exhalation rates from 13 mBq kg–1 hr–1 to 168 mBq kg–1 hr–1 and surface exhalation rates from 302 mBq m–2 hr–1 to 1482 mBq m–2 hr–1. The measured average radon  concentration  in  the  atmosphere of the thermal power plants have been found to vary from 558 ± 40 Bq m–3 to 682± 60 Bq m–3. Based upon these values, the average annual effective doses have also been calculated.

 

Indian J Pure & Applied Physics

Vol. 40, April  2002, pp. 246-251

Quantum chemical study of vibrational spectra and thermodynamic properties of 2-butanone conformers

Archana Sharma, V P Gupta & Ajit Virdi

Department of Physics, University of Jammu, Jammu 180 006

Received 23 October 2001; revised 14 December 2001; accepted 28 December 2001

A complete analysis of the vibrational spectra of 2-butanone is being reported on the basis of quantum chemical ab initio calculations on its two conformers- trans and gauche, using 4-31G extended basis set. The force constant matrices for the two conformers were calculated numerically after purifying the hessian and the dipole derivative tensor. In order to confirm the correctness of vibrational assignments, thermodynamic parameters such as entropy, specific heats at constant pressure Cp and constant volume Cv and enthalpy and Gibb’s free energy for the two conformers have been calculated at 298.15 K using ideal gas, rigid rotator and harmonic normal mode approximations. Calculated thermodynamic parameters are in satisfactory agreement with experimental values.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 252-255

Spectral and normal coordinate analysis of 6-methoxy purine

V Krishnakumar & R Ramasamy*

Post Graduate Department of Applied Physics, Nehru Memorial College, Puthanampatti  621 007

*Department of Physics, Shanmugha College of Engineering, Tirumalaisamudram  613 402

Received 12 December 2001; accepted 6 March 2002

The FTIR spectrum of 6-methoxy purine has been recorded in the region 4000–100 cm-1 and the normal coordinate analysis has been carried out by assuming Cs point group symmetry. All the normal modes of vibrations are assigned and calculations of potential energy distribution are also performed.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 256-263

Ultrasonic investigations of X...HO bond complexes

Madhu Rastogi, Aashees Awasthi, Manisha Gupta & J P Shukla

Department of Physics, Lucknow University, Lucknow 226 007

Received 18 December 2000; revised 24 December 2001; accepted 29 January 2002

The measurements of ultrasonic velocity and density were made for the ternary mixtures of benzyl chloride and bromobenzene with o-cresol in a non-polar solvent, carbon tetrachloride at various concentrations for varying temperatures (30, 40, 50 °C) at a frequency of 2 MHz. Various physical parameters such as adiabatic compressibility, intermolecular free length and their excesses in mixtures, molar sound velocity, molar compressibility, acoustic impedance and degree of intermolecular attraction were evaluated. Weak molecular interactions taking part between the unlike molecules of solute in each mixture have been studied through these physical parameters and their excess values. The ultrasonic velocity shows a maximum for each mixture at specific temperatures, exhibiting maximum interactions occurring between solute molecules at that particular concentration giving rise to complex formation. On further increasing or decreasing the concentration, molecular association decreases. The excess value data evaluated for these mixtures also support the existence of complex formation. The experimental velocities have been compared with theoretically estimated velocities using Nomoto relation and also ideal mixing relation. The deviation of theoretical values of velocities from experimental values also supports the existence of complex formation.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 264-271

Molecular interactions in binary liquid

mixtures – An ultrasonic study

P Subramanyam Naidu & K Ravindra Prasad

Department of Physics, SVUPG Centre, Kavali, (AP) 524 201

Received 19 October 2001; accepted 14 January 2002

Ultrasonic velocities, densities and viscosities have been measured in the binary mixtures: (1) Dimethyl sulphoxide + 1 piperidine ethanol and (2) Dimethyl sulphoxide + 4 hydroxy 1 methyl piperidine in the temperature range 30–50 °C. Free Length Theory (FLT) due to Jacobson and Collision Factor Theory (CFT) due to Schaaffs have been applied successfully in evaluating velocities theoretically. CFT has been found to have an edge over FLT. From the thermodynamic parameters computed, excess parameters like bE, PE, H E, LfE, VE, etc. have been explained in the light of molecular interactions. Interactions of the type dipole-dipole, dipole-induced dipole strong interactions have been reported. At some concentrations, particularly in the mixture of DMSO with 1 piperidine ethanol, dispersive forces and weak bonding dominate the scene. Most of the excess parameters have indicated strong hetero-molecular interactions in both the mixtures.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 272-276

EXAFS study of Sr doped Y0.4Pr0.6Ba2Cu3O7-d*

T S Anvekar, K R Priolkar, V G Sathe1, A V Pimpale1, P R Sarode & V N Kamat Dalal2

Department of Physics, Goa University, Taleigao Plateau, Goa 403 206

1Inter University Consortium for DAE Facilities, University Campus, Khandwa Road, Indore 452 001

2Department of Chemistry, Goa University, Taleigao Plateau, Goa 403 206

Received 24 July 2001; revised 5 December 2001; accepted 3 January 2002

The Cu K-edge extended X-ray absorption fine structure (EXAFS) studies in YBa2Cu3O7-d and Y0.4Pr0.6Ba2-x SrxCu3O7-d with 0 £ x £ 1.25 have been carried out to examine the changes in near neighbour environment of Cu as a function of Sr doping. There is a sudden shift of apical oxygen O(4) towards the CuO planes in compounds wherein superconductivity is restored. This contraction in the Cu(2)-O(4) bond length seems to weaken the Pr-O hybridization and thereby restoring superconductivity. Infrared absorption studies on these compounds also support this picture.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 277-281

Structural and electrical behaviour of

Pb(Mn1/4Cu1/4Mo1/2)O3 ceramics

S K Sinha, S N Choudhary & R N P Choudhary*

University Department of Physics, TM Bhagalpur University, Bhagalpur 812 007

*Department of Physics & Meteorology, Indian Institute of Technology, Kharagpur 721 302

Received 29 March 2001; revised 4 October 2001; accepted 2 January 2002

The polycrystalline samples of Pb(Mn1/4Cu1/4Mo1/2)O3 were synthesized by a high-temperature solid-state reaction technique. A preliminary X-ray structural study of the compound at room temperature shows the formation of a single-phase compound with a non-centrosymmetric space group P2212 of orthorhombic structure. Studies of dielectric constant (e) and loss tangent (tan d) both as a function of frequency (500 Hz-10 kHz) at room temperature and temperature (-100-250 °C) at 10 kHz suggest that the compound undergoes a phase transition at 57 °C. The activation energy (Ea) of the compound was calculated from the plot of dc conductivity versus inverse of absolute temperature. Variation of dc resistivity with electric field (8.55-85.47 kV/m) at room temperature and variation of dc resistivity (1012-106 Wm) with temperature (100-300 °C) at a constant electric field of 85.47 kV/m showed the semiconductor characteristics of the material.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 282-289

Thermomagnetic behaviour of Gd substituted ferrite magnetic fluids*

Trupti Upadhyay1 & Kinnari Parekh

Laboratory of Magnetic Fluids, Department of Physics, Bhavnagar University, Bhavnagar 364 002

1Physics Department, S V M Institute of Technology, Bharuch 392 001

Received 15 May 2001, revised 26 November 2001; accepted 1 February 2002

Gd substituted Mn-Zn (50%) ferrite magnetic fluids have been synthesized to achieve a high value of pyromagnetic co-efficient. Thermo-magnetic behaviour of the fluids are studied with the temperature, field and different concentrations of Gd. The results indicate that the substitution of Gd (2.5%) increases the particle size without altering its magnetic moment while on further addition of Gd (5%) will increase the magnetic moment with the same particle size. It is also observed that Gd (5%) substituted sample has higher value of pyromagnetic coefficient compared to that of the parent system Mn-Zn (50%) ferrite and Gd (2.5%) substituted ferrite.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 290-296

Effect of strontium impurity ions on conductivity of KBr:Sr

G Saibabu1, N Vasanth Kumar2, C Suresh Reddy3, D Sri Kanth4 & A Ramachandra Reddy4

1Department of Physics ,  SC Railway Junior College, Kazipet, (AP) 506 003

2Sanchara Nigam, Warangal District (AP)

3HBL NIFE Power Systems Ltd. Lalgadi, Malakpet, (RR Dist), Hyderabad, (AP) 500 014

4Department of Physics, Regional Engineering College, Warangal, (AP) 506 002

Received 24 July 2001; revised 16 January 2002; accepted 4 February 2002

The study on ionic conductivity versus reciprocal temperature of pure KBr and KBr crystals doped with 0.075, 0.35 and 0.75 mole % strontium has been carried out in as-grown quenched from elevated temperatures (200, 300 and 400 °C) and deformed by different percentages. The plots exhibits three well-known regions as II, III and IV (extrinsic regions). But the region IV is not shown in the plots. The intrinsic region I was not observed in the plots as the conductivity measurements were taken up to 575 °C. From the analysis of these plots activation energies for the migration of cation vacancy, the association of strontium ion with cation vacancy in the lattice of KBr crystals are calculated. The values are compared with previously reported values. Further the variation in conductivity is explained on the basis of formation of impurity-vacancy dipoles, vacancy-vacancy pairs (which appear in the form of precipitation), storage of cation vacancies in a form of defects; introduction of fresh dislocations etc.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 297-300

Band gaps of nanocomposites

G P Joshi, R Mangal, N S Saxena & T P Sharma

Condensed Matter Physics Laboratory, Department of Physics, University of Rajasthan, Jaipur 302 004

Received 22 January 2002; accepted 4 March 2002

Nanocomposites of Ni-Zn with copolymer matrix of aniline formaldehyde in presence of varying concentrations of zinc ions have been studied at room temperature and normal pressure. The absorption spectra of these materials are recorded by a Hitachi spectro-photometer, model U-3400, in the wavelength range 850-410 nm. From the analysis of absorption spectra, nanocomposites copolymer of aniline formaldehyde Ni1-x ZnxFe2O4 (x = 0.0, 0.2, 0.4, 0.6 and 0.8) have been found to have direct band gaps ranging from 1.54 eV to 1.88 eV. Sudden increase in the band gap of these composites in the vicinity of composition from x = 0.2 to x = 0.4 has been explained on the basis of structural change at those concentrations of Zn.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 301-303

NOTE

Structure, conductivity and magnetic study of

Sr2Zn2Al2Fe10O22 ferrite

M Y Salunkhea, N Y Lanjeb & D K Kulkarnia

aDepartment of Physics, Institute of Science, Nagpur (MS)

bDepartment of Physics, Jagat Science College, Goregaon (MS)

Received 24 July 2001; revised 12 December 2001;

accepted 2 January 2002

Zinc substituted strontium Y type hard ferrite with the chemical formula Sr2Zn2Al2Fe10O22 is prepared using AR grade reactants in the proper stoichiometric proportions by solid state reaction at 850 oC. The XRD pattern of the compound showed a presence of single crystalline phase having a hexagonal structure with lattice parameter a = 5.614 Å and c = 53.736 Å. Magnetic susceptibility is measured between room temperature and 950 K by Gouy’s method. These measurements showed ferrimagnetic nature of the compound up to 896 K and then it becomes paramagnetic. The observed high value of Curie temperature is due to high percentage of Fe+3 ions. The Curie molar constant is also calculated. Electrical conductivity measurements showed slight deviation from linearity near the Curie temperature. The energy of activation is found to be 0.99 eV. Variation of dielectric constant with temperature at constant frequency of 50 Hz was determined by using digital LCR meter. The ferro to para electrical transition temperature Tc was found to be 301 K, close to room temperature. It is interesting to note here that the seasonal changes will heavily influence the room temperature behaviour. The observed results follow the well-known Curie-Weiss law for the dielectrics.

 

Indian Journal of Pure & Applied Physics

Vol. 40, April 2002, pp. 304-306

News Scan

Bose-Einstein condensate – A new state of matter

Matter was known to exist in three phases, viz. solids, liquids or a gas. Later on plasma, a highly ionized phase was added to it. Now an entirely new extreme state of matter called the Bose-Einstein Condensate (BEC) has been created in the laboratory. From the energy level point of view, solids have the lowest energy levels (corresponding with the lowest temperatures), while liquids and gases have increasingly higher levels. At the top end of this scale, we can add plasmas, which are energetic enough to emit all kinds of energy - in the form of high-energy particles, heat and light (photons). Bose-Einstein Condensates represent a fifth phase of matter even before solids on this scale. BECs are envisaged to have unheard of applications in the fields of lithography, nanotechnology and holography in future, which will give a further boost to our quest for micro-miniaturization as also to other areas.