023023   Chaman M;Verma P K (Physics Dep, Aligarh Muslim University, Aligarh-202 002) : Laser raman and FTIR specra of 2,3,5-tri-iodobenzoic acid. Indian J Phys-Pt B 2003, 77(3), 315-18.

The Strokes as well as anti-Strokes Laser Raman spectra of 2,3,5-tri-iodobenzoic acid have been recorded in the regions 150-4000 cm^-1 on Spectra Pro-500 Laser Raman Spectrometer using 4880 A° emission line of Argon ion Laser as a source of excitation. FTIR spectra of above compound have also been recorded in solid phase as well as in liquid phase in the regions 400-4000 cm^-1 on Perkin Elmer FTIR spectrophotometer. The vibrational analysis has been carried out by taking this molecule to belong to Cs-point group. The observed frequencies were assigned to various modes of vibration on the basis of intensity, frequenceies from similar molecules.

4 illus, 4 tables, 18 ref

023022   Chakraborty B;Paul S N;Bhattacharya S K (Department of Mathematics, Jadavpur University, Jadavpur, Kolkata-700 032) : Collective effects of bound electrons, free electrons and ions in a plasma. Indian J Phys-Pt B 2003, 77(3), 335-43.

The collective behaviour of a plasma is investigated when the plasma is considered to be as mixture of compressible fluids of free electrons, free ions, weakly bound electrons and neutral atoms. A classical theory has been developed for understanding the dynamical behaviour of such a plasma. Non-relativistic closed system of fluid equations of a plasma is used which contain a population of boun electrons, the associated ions, the free electrons and free ions. It is found that the Poynting theorem for energy conservation and the Maxwell stress elements have some new terms. The particle dynamical analysis and the energy exchange aspects of free electrons and bound electrons have also been considered. Kinetic and kinematical aspects of this model and other models have been discussed breifly.

8 ref

023021   Chakrabarti C G;De M K (Dept. of Applied Mathematics, Calcutta University, Kolkata-700 009) : Statistics of open multi-component system : probability chemical equilibrium and stability. Indian J Phys-Pt B 2003, 77(5), 477-80.

Deals with the drivation of the probability of an open multi-component system, the condition of chemical equilibrium, the law of mass action and the criteria of chemical stability on the basis of a probabilistic model of the open multi-component system.

12 ref

023020   Bhattacharya S K;Paul S N;Chakraborty B (NO, Faculty of Science, Serampore Girls's College, Serampore, Hooghly-712 201 West Bengal) : Effects of non-thermal electrons and negative ions on ion-acoustic solitary waves in a bounded plasma. Indian J Phys-Pt B 2003, 77(3), 327-34.

The effects of non-thermal electrons and negative ions on ion-acoustic solitary waves bounded in a finite geometry have been investigated theoretically using pseudo-potential technique. It is found that finite geometry of the bounded plasma has signficant contribution to the instability of the wave. The structure of the solitary wave is then anaysed as function of the parameter β which measures the deviation from the termalised state. It is seen that when one considers non-thermal electrons and negative ions, both compressive and rarefactive solitons are found. In the absence of negative ions, solitary wave will not exist in bounded plasma for any value of β for non-thermal electrons. But, the existence of solitary wave is possible in unbounded plasma in presence of the non-thermal electrons for large values of β.

4 illus, 36 ref

023019   Anand A;Narayanamurthy C S (Applied Phys Dep, Faculty of Technol & Engng MS Univ of Baroda, Kalabhavan, P.B. No.51, Vadodara-390 001) : Collimation testing using two-wave mixing in photorefractive crystal. J Optics 2002, 31(4), 169-79.

A new method to test collimation of laser beam using photorefractive crystal is developed. The method uses two wave mixing geometry with Bi₁₂TiO₂₀ as the recording medium. The diffraction efficiency of two wave mixing serves as the parameter for testing the collimation.

9 illus, 2 tables, 21 ref

023018   Afrafin S (Dept. of Physics, College of Science, Sultan Qaboos University, P O Box No. 36, Al-Khoudh 123, Sultanate of Oman) : Estimation of the parameters of simple geological bodies from gravity anomalies revisited. Res J Chem Envir 2002, 6(4), 73-7.

A method for determining the body parameters of spherical and cylinderical bodies by utlizing various fractions of the maximum amplitude of the anomaly, their corresponding widths, area under the gravity curve and excess mass has been described. Two procedures, one based on area under the gravity curve and the other on the excess mass, for estimating the dimensions of the bodies have been presented. The radial symmetry of the gravity anomaly due to a sphere has been utilized to calculate the excess mass from a single profile. The radius determined from the excess mass is independent of the depth estimate. This method of determining the radius is more robust than the one based on calculating from the area. The effects of truncation and zero-level errors on the estimates radius has also been discussed.

5 illus, 1 table, 12 ref

024879   Zade S D (NO, Lokmanya Tilak Mahavidyalaya, Wani, Dist. Yavatmal-445 304, Email: sachinzade15@rediffmail.com) : Molecular interactions of coumaran-3-ones in polar and non polar solvents using ultrasonic interferometer. Rasayan J Chem 2011, 4(3), 620-9.

The molecular interaction between solute-solute and solute-solvent was studied with the help of acoustic properties determined by ultrasonic interferometer at 303.15 K in polar acetone and non polar dioxane solvents. The effect of introduction of metal ions viz Cu(II), Fe(III) in the same solution was found out. Also the effect of position of same group at ortho or para position on the molecular interaction was simultaneously examined.

6 illus, 5 tables, 23 ref

024878   Srivastava S;Prasad B M K;Wadhwa P (Applied Science and Humanities Dep, Dronacharya College of Engineering, Gurgaon-123506, Email: smitaamit70@gmail.com) : Luminescence: a sensitive tool. Dronacharya Res J 2011, 3(1), 120-6.

The term luminescence is used to describe a process by which light is produced other than by heating. Everyone is familiar with the production of light from heat ie incandescence. The Sun gives off both heat and light as a result of nuclear reactions in its core. An incandescent light bulb gives off light when a wire filament inside the bulb is heated to white heat. One can read by the light of a candle flame because burning wax gives off both heat and light. But light can also be produced by other processes in which heat is not involved. For example, fireflies produce light by means of chemical reactions that take place within their bodies. They convert a compound known as luciferin from one form into another as that process occurs, light is given off. Two forms of luminescence can be identified depending on the amount of time the emitted light continues to glow. They are Phosphorescence and Fluorescence. First one refers to the release of light that lasts no more than about 10 nanoseconds (10 billionths of a second) after it begins. The second one refers to the release of light that lasts longer than 10 nanoseconds. The types of luminescence depend on their specific properties and the nature of the substance. The application of luminescence depends on the cause by which it created. The science of Luminescence is very much alive. New devices like LEDs or new application areas in the medical arena have fuelled research on luminescent compositions and form factors. In addition, the science of luminescence integrates chemistry, materials science, and physics. In this field of overlapping disciplines, many exciting challenges are still in front of us.

12 illus, 18 ref

024877   Roy S;Ahmed G A (Optoelectronics and Photonics Lab, Physics Dep, Tezpur Univ, Tezpur-784 028, Email: rsanchital@gmail.com) : Computation of scattering by spherical particles with a gamma size distribution. J Optics 2010, 39(2), 76-81.

The theoretical analysis and development of a new program for accurate measurement of volume scattering and Mueller scattering matrices of spherical particles is reported. A unique y size distribution function is incorporated into the program. The output of the program was compared with the output of a standard software for calibration and to ascertain the accuracy and reliability of the developed program.

2 illus, 8 ref

024876   Magalhaes P A A;Neto P S;Magalhaes C A (NO, Pontificia Universidade Catolica de Minas Gerais-Av. Dom Jose Gaspar, 30535-610, Belo Horizonte, Minas Gerais, Brazil, Email: paamj@oi.com.br) : Modified carre algorithm for phase shifting interferometry. J Optics 2010, 39(1), 5-21.

The idea is to develop a generalization of Carre that is not restricted to four images. Errors and random noise in the images cannot be eliminated, but the uncertainty due to its effects can be reduced by increasing the number of observations. The advantages of the proposed algorithm are its precision in the measures taken and immunity to noise in images. The objective is to get a method with high precision and accuracy in measurements, fast processing and low sensitivity to noise.

5 illus, 3 tables, 14 ref

024875   Giridhar S (NO, Indian Institute of Astrophysics, Bangalore-560 034) : Advances in spectral classification. Bull Astr Soc India 2010, 38(1), 1-33.

In this article author gave an overview of the developments in the field of spectral classification and its continued importance in the fields of stellar and galactic evolution. The extension of MK system to cool stars as well as refined classification of the hot stars using the new data obtained from modern ground based facilities and space missions has been described. A brief summary of automated methods of spectral classifications developed for the quick and objective classification of the ongoing and future surveys is presented. A new spectral class encoding system developed for exploitation of databases is described. Recent large scale spectral classification catalogues are listed.

7 illus, 93 ref

024874   Dutta S;Mukhopadhyay S (Physics Dep, Burdwan Univ, Golapbag, Burdwan-713 104, Email: soma.dtta@gmail.com) : An all optical approach of frequency encoded NOT based latch using semiconductor optical amplifier. J Optics 2010, 39(1), 39-45.

In case of super-fast optical computation and communication, frequency encoding techniques are found to be very promising and reliable one. Optical logic gates based on the principle of frequency conversion of some nonlinear materials play the key role for the implementation of a frequency encoded data processing system. Again semiconductor optical amplifier has already been established successfully for frequency conversion. In frequency encoding system, different frequencies of light signal are used for representation of binary bits 0 or 1 instead of intensity variation. For example 0 and 1 bits of Boolean logic can be coded by two different frequencies of light signal V₁, and v₂, respectively. In this communication, we propose the method of developing an optical memory or a NOT based latch. Several types of phase encoded, polarization encoded and intensity encoded optical memories have been reported earlier, including latch also, whereas this proposal have been planned to develop an all optical latch logic using frequency encoded principle and it offers a reliable and faithful processing rather than other established techniques.

3 illus, 1 table, 16 ref

024873   Divakara S;Reddy T;Roy S;Siddaraju G N; Somashekar R (Studies in Physics Dep, Mysore Univ, Manasagangotri, Mysore-570 006, Email: rs@physics.uni-mysore.ac.in) : Changes in stacking faults and microstructural parameters of dry and wet bivoltine silk fibers using whole powder pattern fitting technique. J Polym Mater 2010, 27(2), 135-48.

The behaviour of silk fibers in dry and wet conditions has been investigated using WAXS technique. In wet condition of fibers, there is a possibility of modification in configuration of Ala-Gly-Ser Residues, which results in different polymer network. This aspect has been quantified in terms of microstructural parameters like crystallite size, lattice strain, stacking and twin faults by using indigenously developed line profile analysis and whole powder pattern fitting technique.

6 illus, 3 tables, 16 ref

024872   Chakraborty R (Applied Optics & Photonics Dep, Calcutta Univ, 92 A.P.C. Road, Kolkata-700 009, Email: srirajib@yahoo.com) : Low temperature bonding of microstructured fiber sensors. J Optics 2010, 39(1), 22-31.

The paper describes different low temperature bonding for fiber-optic sensors. The physical explanation of the different bonding methods is also given. Sol-gel based bonding proposed in this paper can eliminate the problem of thermal mismatch due to introduction of an intermediate layer.

8 illus, 12 ref

024871   Baishya A C;Srivastav S K;Sahu P P (Electronics & Communication Engg Dep, Tezpur Univ, Assam, Email: pps@tezu.ernet.in) : Cascaded mach zehnder coupler for dynamic EDFA gain equalization applications. J Optics 2010, 39(1), 46-52.

In this paper, we have presented design of Cascaded Mach Zehnder (CMZ) coupler consisting of Mach-Zehnder (MZ) section of equal arms and Mach-Zehnder section of unequal arms (delay line) for dynamic equalization of EDFA gain spectrum. The simulation results for the beam propagation of the device are evaluated by using BPM software. The device length estimated in simulation is -8 mm which is - 10 times less than that of the existing CMZ coupler. Dynamic equalization of EDFA gain spectrum is obtained by using low power thermooptic phase shifter placed on the MZ arm.

3 illus, 1 table, 10 ref

020922   Yadav R K;Singh N P;Yadav R A (Department of Physics, Udai Pratap (Autonomous) College, Varanasi-221 002) : Vibrational studies of trifluoromethyl benzene derivatives: II. 5-amino-2-fluoro and 5-amino-2-chloro benzotrifluorides. Indian J Phys-Pt B 2003, 86(4), 421-7.

Raman spectra of 5-amino-2-fluoro and 5-amino-2-chloro benzotrifluorides have been recorded in the liquid phase on a Jobin Yvon Ramanor HG.2S and a Spex 1403 spectrometers in the spectral range 100-4000 cm^-1. Polarisation measurement for the observed Raman lines has also been carried out. Infrared spectra of these two compounds have been recorded in the spectral range 200-4000 cm^-1 on a Perkin Elmer 783 and on an FTIR model Cygnus-100 (Mattson Co.) spectrometers. Assuming C point group symmetery for these molecules, vibrational assignments for the observed frequencies have been proposed. Out of the 45 expected normal modes, 43 could be assigned on the basis of the observed frequencies directly and 2 are estimated from the assignments of overtone/combination bands.

4 illus, 19 ref

020921   Yadav B S;Gupta K;Subhash Chand (Molecular Spectroscopy and Biophysics Laboratory, D N (P.G) College, Meerut-250 002) : Electronic spectral studies of 2-chloro-6-methoxypyridine in various solvents. Indian J Phys-Pt B 2003, 86(4), 417-20.

Reports the electronic transition bands of 2-chloro-6-methoxy pyridine molecule in liquid state and the effect of α-halogen atom on the absorption intensity of the B-band (characteristic band (Characteristic band of aromatic ring). The π-π^* transition (E₂-band) has shown the usual behaviour towards the substitution and the polarity of the solvents. But the n-π^* transition (R-band) has evidenced a usual behaviour towards the solvent polarity and unusual behaviour towards the substitution (i.e. the n-π^* transition has shown red shift with respect to the n-π^* system of pyridine). The halogen atom and/or ortho para directing group (having high potential for a large inductive effect) have shown a marked influence on the sp² electrons of the N-atom of the ring. As a result, the B-band has evidenced an unusual behaviour i.e. it has not shown a hyperchromic effect with increase in the polarity of the solvent.

4 illus, 19 ref

020920   Watekar P R;Panda J R;Goswami M L N;Kher S; BIswas J C;Acharya H N (Optical Fiber Unit, CRF, Indian Institute of Technology, Kharagpur-721 302) : Emission characteristics of erbium/ytterbium-doped optical fibers. Indian J Phys-Pt B 2003, 86(4), 439-41.

Modified Chemical Vapor Deposition (MCVD) process along with solution-doping technique is used for the fabrication of Er/Yb-doped optical performs and fibers. The spectral variation of amplification of spontaneous emission (ASE) has been measured by pumping Er/Yb-doped fiber with the wavelength of 800 nm at 100 mW power. Peak emission-wavelengths hae been obtained at 971 nm and 1050 nm for Yb³⁺ and 1537 nm for Er³⁺. The emission cross-sections for Yb³⁺ are found using the fluorescence characteristics of the fiber and the absorption cross sections are calculated using Mc-Cumber relationship. This work will be useful for designing Er-doped and Er/Yb co-doped amplifers and lasers.

4 illus, 7 ref

020919   Sinha M S (NO, , Sputnik, P-39, Recol Park, Durgapur-713 216) : Muon physics. Indian J Theor Phys 2002, 50(4), 1-10.

The talk has been divided into two parts: the first part deals witht eh discovery of muon in cosmic rays and the determination of its mass, mean-life and its decay mode as established by experiments of Powel showing that the muon does not possess any strong nuclear interaction and is nothis but a heavy electron. The second part of the talk deals with experiments on artificially produced muon beams leading to the discovery of two kinds of neutrinous vμ and v_a and finally the μ - e universality in nature.

020918   Singh S P;Sinha S K (Physics, L S College, B B A Bihar University, Muzaffarpur-841 004) : Thermodynamics of polar fluid mixtures of hard non-spherical molecules. Indian J Phys-Pt B 2003, 86(4), 457-63.

The problem of calculating the thermodynamic properties of polar fluid mixtures of hard non-spherical molecules is studied. Explicit analytic expressions for the virial coefficients and Helmholz free energy are given. Numerical results are estimated for the third virial coefficient, equation of state and excess internal energy of quadrupolar hard Gaussian overlap fluid mixtures. They are found to depend on the conditions and shape parameters.

4 illus, 4 table, 16 ref

020917   Singh S K;Sushil Kumar;Gwal A K (Space Science Laboratory, Electronics Dep, Barkatullah University, Bhopal-462 026) : Daytime very low frequency (VLF) emissions observed at Maitri station, Antarctica. Indian J Phys-Pt B 2003, 86(4), 451-5.

Deals with the study of naturally occurring Very Low Frequency (VLF) ratio waves at Indian Antarctic Station, Maitri (70° 46'S, 11°44'E) on the basis of routine continuous observation made during day time. From the detail analysis of daytime data on the basis of continuous observation made at the ground station, author have presented a few of VLF phenomena such as rising types of emission - discrete and periodic emissions. These recent observations at Maitri, Antarctica may reveal propagational characteristic for the various VLF emissions generated during daytime.

6 illus, 31 ref

020916   Singh C;Singh R (Phys Dep, S P College, Hilsa, Nalanda (Bihar)) : Study of quark-line-rule violation in J/decays. Indian J Theor Phys 2002, 50(4), 281-5.

When Ψ→p width is compared with Ψ→K^* K, a substantial violation of SU(3) symmetry is indicated whereas SU(3) symmetry is valid in other decay channels like Ψ→K_LK_s. We have tried to search a possible answer to this SU(#) violation. The strong interaction part of the amplitude for J/Ψ decays into specific final hadronic states is computed by evaluating corrections arising from unitarity to the OZI rule. Dispersion relations for the relevant amplitudes are evaluated keeping only the contributions of charmed-hadron states to the absorptive part and assuming Regge asymptotic behaviour for charmed hadrons to ordinary hadrons.

9 ref

020915   Shetty B J;Kshirsagar R J;Balasubramanian T K (Spectroscopy Division, Modular Laboratories, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085) : Fourier transform emission spectroscopy of the A<. Indian J Phys-Pt B 2003, 86(4), 405-15.

For the forst time, the electronic spectrum of the specific isotopomer ⁷⁴Ge⁸⁰Se of germanium monoselenide was produced in a microwave discharge through an electrodeless quartz tube containing the single isotopes of ⁷⁴Ge and ⁸⁰Se and neon as carrier gas. The bans in the 35000-25000 cm^-1 region belonging to the main transition A¹™-X¹A¹Σ ⁺ were recorded on BOMEM DA8 Fourier transform spectrometer under medium (10 cm^-1) and high (0.05 cm^-1) resolutions. In all, an overwhelming 344 bands, including several new bands in the 28000-25000 cm^-1 region have been assigned to the A-X system. The observation of isotopically pure spectrum has enabled a comprehensive vibrational analysis of the A-X bands. The Franck-Condon factors (FCF) and r-centroids were computed and the observed intensities were compared with the FCFs. To facilitate the FCF calculations the rotational analysis of the (0-5) band had also been carried out.

4 illus, 4 tables, 14 ref

020914   Sarkar D;Sarkar P P;Chowdhury S K (USIC, University of Kalyani, Kalyani-741 235) : Theoretical and experimental investigations on the frequency selective property of an array of slotted dipoles. Indian J Phys-Pt B 2003, 86(4), 399-403.

A frequency selective surface (FSS) comprising of a two dimensional array of slotted dipoles resonant at a single frequency is proposed. A computationally efficient method for analyzing this FSS is presented. The formulation is carried out in the spectral domain where the convolution form of the integral equation for the induced current reduces to an algebraic one and the Spectral-Galerkin technique is used to solve the resulting equation. Entire-domain basis function that satisfies the edge condition is introduced to expand the unknown induced current on the complimentary structure i.e. an array of metal printed dipoles. Using Babinet's principle for complementary screen, the transmitted elecric field for the structure of slotted dipoles have been calculated. This theoretical result has been compared with the experimental data also. The theoretical and experimental data indicate that this structure can be used as a band pass filter.

3 illus, 12 ref

020913   Ravindra K;Sarma A D;Prasad M V S N (R & T Unit for Navigational Electronics, Osmania Univeristy, Hyderabad-500 007) : Adaptive polynomial path loss model at UHF frequencies for mobile railway communications. Indian J Radio Space Phys 2002, 31(5), 278-84.

Study of channel behaviour for efficient spectral usage has been the key aspect in the design of third generation (3G) mobile communications systems. Modelling of UHF signals acquired in a moving train corresponding to a distance of 180 km in northern India starting from New Delhi to Sharanpur, covering various environmental zones. A new sixth order adaptive polynomial model is proposed to further model the deviation of earlier adaptive three coefficient model. The standard deviations of the predictions made by the proposed model from the experimental data are within 2.1 dB throughout the region of experimentation in contrast to a maximum of 24 dB reported earlier.

9 illus,2 tables,16 ref

020912   Ramola R C;Yamada Y;Miyamoto K;Miyamoto K T; Shimo M (Dep of Physics, H N B Garhwal University, Badshahi Thaul Campus, New Pehri Garhwal-249 199) : A study of radon exhalation rates from water samples by using liquid scintillation counter. Indian J envir Prot 2002, 22(8), 847-51.

The concentrations of radon were determined in the water samples from different parts of Japan by using liquid scintillation technique. The radon values are found to vary from 0.14 to 2870 Bq/L. The decay patterns of each sample were obtained and were compared with the theoretically calculated values. In addition, measurements were made to find out the variation of radon concentration with the depth of the water sample. An attempt was also made to find out the exhalation rate and decay constant of radon from the surface of water. A brief description of the variation of radon decay/constant with the area of the surface water is presented.

7 illus, 1 table, 13 ref

020911   Ramasamy V;Dheenathayalu M;Ponnusamy V; Hemalatha J;Presannalakshmi P (Physics Dep, Annamalai University, Annamalainagar-608 002) : FTIR-characterisation and thermal analysis of natural calcite and aragonite. Indian J Phys-Pt B 2003, 86(4), 443-50.

The data given in the literature for the infrared identification of carbonate minerals is summarised, and a technique is described which may be used to identify calcite, aragonite, kaolinite, nacrite, feldspar, quartz, montmorillonite, illite, tourmaline, gibbsite and saponite by the analysis of their infrared absorption bands. The fundamental vibrations of aragonite and calcites are identified. The changes in these modes are analysed through thermal treatment. Structural changes occur in aragonite of coral reef to calcite beyond 350°C. The quality of calcite is assessed by detecting the presence of quartz and dolomite.

4 illus, 2 tables, 32 ref

020910   Rajneesh Kumar;Choudhary S (Mathematics Dep, Kurukshetra Univ, Kurukshetra-136 119) : Interaction due to mechanical sources in a micropolar elastic medium with stretch. Indian J Theor Phys 2002, 50(4), 261-79.

The dynamic response of a homogenous isotropic micropolar half-space with stretch subjected to a set of normal point sources are investigated. The intergral transforms have been inverted by using a numerical technique to obtain the normal displacement, normal force stress, tangential force stress, tangential couple stress and first moment in the physical domain for the two different sources. The result of these quantities for magnesium crystal like material are given and illustrated graphically.

8 illus, 25 ref

020909   Prasad R S;Sharma N K (Physics Dep, Magadh University, Bodh-Gaya-824 234) : Electronic spectra of oxadiazoles. Indian J Phys-Pt B 2003, 86(4), 429-34.

MRINDO/S calculation augmented by singly excited configuration interaction was performed on oxadiazoles. Net charge distributions, ionization potentials and electronic spectra of oxidazoles are reported. The Rydberg transitions are also discussed.

3 tables, 15 ref

020908   Lo'pez-Bonilla J L;Gaftoi V;Ovando G (NO, , ) : On some identities between Riemannian variants. Indian J Theor Phys 2002, 50(4), 257-9.

Consider certain invariants of 3rd order in the Riemann tensor components, and exhibit how a linear combination of them illustrates four interesting identities.

10 ref

020907   Karmakar P K;Maiti M;Mitra A (NO, Institute of Radiophysics and Electronics, University of Calcutta, 92, A P C Road, Calcutta-700 009) : Radio visibility at microwave frequencies. Indian J Radio Space Phys 2002, 31(5), 264-9.

Radio visibility through water vapour has been studied over Calcutta at microwave / millimetre wave frequencies. Due to large abundance of water vapour over Calcutta, the integrated water vapour content restricts the radio visibility approximately up to 5 km at different microwave/millimetre wave frequencies. The study has been restricted to only the total absorption (dB) part of the propagation parameters of radio waves. the vertical layers of atmosphere have been divided into 10 m slabs with the assumption that the meteorological parameters remain unchanged quantitatively within any of these slabs. The height at which the variation of total absorption (dB) is less than or equal to 1% of that of the immediate preceding height ( which is one slab thickness less), is , here, defined as 1% height limit. It has been found that beyond this height the radio receivers at microwave millimeter wave frequency suffer no appreciable change in the total absorption.

5 illus,1 table,17 ref

020906   Iqbal M;Quamar J (Institute of Space and Planetary Astrophysics (ISPA), University of Karachi, Karachi-75270) : Planetary orbits around a spinning gravitating star. Indian J Phys-Pt B 2003, 86(4), 379-8.

It is an empirical fact based on solar physics of sunspots, that sun and stars are spinning gravitational sources for bodies in orbit in any such solar system. Thus, a planetary theory for the gravitational field of a star or a satellite dynamics around a (spinning) planet - including the problem of artificial satellites - should in principle, take into account the possible effect of axial symmetry. But the existing formalisms of gravitation physics do not address the problem of spin referred to above. Proceses the following strategy to handle this kind of computational physics. The calculations suggest that this kind of spin should give rise to a slight residual perturbation on constant areal velocity, computed by the standard model of orbital theory. In particular, the second law of planetary motion might require revision. Also, it turns out that the classical result of Kepler is recoverable from out result as a special case.

21 ref

020905   Hashim I (School of Mathematical Sciences, Faculty of Science & Technology, National University of Malayasia, 43600 UKM Bangi, Selangor, Malaysia) : On oscillatory Benard-Marangoni convection in a fluid layer with strong surface deformation. Indian J Phys-Pt B 2003, 86(4), 469-71.

Linear stability theory is applied to the problem of the onset of oscillatory Benard-Marangoni convection in a horizontal layer of fluid bounded from below by a rigid boundary and above by a strongly deformable free surface and heated from below. Obtains critical values of the Prandtl number below which convection sets in as oscillatory motions and give an example of a situation in which two different modes of instabilities coexist.

1 illus, 1 table, 6 ref

020904   Harun S W;Poopalan P;Ahmad H (Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia) : Double pass L-band erbium-doped fiber amplifier with enhanced gain characteristics. Indian J Phys-Pt B 2003, 86(4), 435-7.

A double pass long wavelength band (L-band) erbium-doped fiber amplifer (EDFA), which can effectively suppress and completely exploit the backward conventional band (C-band) amplified spontaneous emission (ASE) with a reflector, is presented. Circulator or broadband fiber Bragg grating (FBG) is used as the reflector to doubly passing the forward ASE and signal in the erbium-doped fiber (EF). The gain of the double pass EDFA can be improved by about 10dB with an extra noise figure penatly of about 3dB, compared to the conventional single pass EDFA.

4 illus, 5 ref

020903   Gupta S S (Theoretical Physics Dep, Indian Association for the Cultivation of Sci, Calcutta-700 032) : Optical activity in a spacetime with torsion. Indian J Theor Phys 2002, 50(4), 21-32.

A spacetime with torsion produced by a second rank antisymmetric Kalb-Rammond (KR) filed coupled to a Maxwell field, in accordance with a recent proposal (PM and SS), is shown to lead to an optical activity in synchrotron radiation from cosmologically distant radio sources. If one considers a parity violating extension of spacetime torsion, then helicity flip of fermion also takes place is such a back ground.

13 ref

020902   Darwish A A (Department of Physics, Faculty of Science, Alexandria University, Alexandria, Egypt) : Determination of the expected solar diurnal vectors of cosmic rays on the earth. Indian J Phys-Pt B 2003, 86(4), 385-9.

Using the best-fitting technique, determined the parameters of the solar diurnal vector in free space by considering one space anisotropy of the flat spectrum and by using the observed cosmic-ray data of the deep river neutron monitor as well as the socorro underground muon telescope over two solar cycle. Positive results have been obtained for these parameters. Further, Uses the above parameters of the solar diurnal vector in free space to calculate the expected solar diurnal vectors of cosmic rays on the earth for other 10 neutron monitor stations. Comparison between the observed and the expected solar diurnal vectors of the above stations shows that both the expected as well as the observed amplitude and phase are very close to each other for stations of low cut-off rigidity. However, as the cut-off rigidity increases, the expected and the observed amplitude and phase differ from each other.

5 illus, 15 ref

020901   Chudinov P S (Theoretical Mechanics, Moscow Aviation Institute, 125993 Moscow, Russia) : Optimal angle of launching a point mass in a medium with quadratic drag force. Indian J Phys-Pt B 2003, 86(4), 465-8.

The problem of finding an optimal angle of launching a point mass in a medium with quadratic drag force is considered. An equation for determining an approximate value of this angle is obtained. After finding the optimal angle of launching, eight main parameters of the particle motion are analytically determined. These parameters are used to analytically construct six main functional relationships of the problem.

8 illus, 10 ref

020900   Chandra H;Kovalam S;Vincent R A (Physical Research Laboratory, University of Adelaide, Ahmedabad-380 009) : Short period oscillations in mesosphere. Indian J Radio Space Phys 2002, 31(5), 237-49.

Long sequences of the hourly average zonal and meridional wind components obtained by MF spaced antenna radars at Davis (69°S, 78°E), Buckland Park (34°S, 138°E) and Christmas Island 92°N, 1557°W) are spectrally analyzed to study the short period oscillations in mesospheric winds. Data lengths covering a minimum of four years at each of the stations, five altitudes used for average (84-92 mk) and the windows of 10, 20 and 40 days used in estimating power spectra give high reliability and spectral resolution. Apart from the tidal components at 24, 12, 8 and 6 h there are oscillations with period ranging between 4.8 h and 12 h. Moving power spectra are obtained to study the seasonal dependence of the short period (smaller than 12 h0 oscillations. The wave activity is strongest during June solstice and weakest during equinoxes at each of the locations. The presence of similar features at high, mid and low latitudes indicates the global nature of such oscillations. The seasonal dependence of the wave activity is in agreement with the recently reported observations of waves with periods between 7.5 and 10.5 h seen in the meteor radar data at south pole. Oscillations with periods of 4.9 - 5.2 h and 7.2 - 7.5 h are also seen.

9 illus,17 ref

020899   Calla O P N;Singh R K (International Centre for Radio Science, , "Om Niwas", A-23, Shastri Nagar, Jodhpur-342 003) : Emission characteristics of dry and wet loamy sand soil layered pack at microwave frequencies. Indian J Radio Space Phys 2002, 31(5), 285-92.

The emissivity estimated at different moisture content and at different frequencies is reported for a typical loamy sand soil. It is observed that the emissivity of soil pack depends on frequency as well as on moisture content and the depth of layer at which moisture is present. The estimated emissivity also shows dependence on look angel and polarization. The estimated values of emissivity can be used for designing passive remote sensing instruments.

9 illus,1 table,9 ref

020898   Bodosa G;Borkakati A K (Mathematical Sci Dep, Tezpur Univ, Napaam-784 028) : On some unsteady free convection MHD flow of a second order fluid between two heated vertical plates. Indian J Theor Phys 2002, 50(4), 287-96.

The laminar free convection flow of an electrically conducting second order fluid under the transverse magnetic fleld over a plate has been studied. Exact solution can be obtained the fluid velocity and the temperature profile with the help of the perturbation technique and the flow flux, heat flux and skin-friction have also been found. The effect of Prandtl number, Grashoff number, magnetic parameter and the elastic parameter on the fluid vclocity and temperature profile are shown graphically and discussed.

2 illus, 8 ref

020897   Bhalekar A A (Chemistry Dep, Nagpur University, Amravati Road Campus, Nagpur-440 033) : Universe of operations of thermodynamics vis-a-via boltzmann intergo-differential equation. Indian J Phys-Pt B 2003, 86(4), 391-7.

Using the Boltzmann intergo-differential equation, traces, the origin of the natural fluctuations which in essence, is the case of breakdown of the equal a priori probability for binary collisions and their reverse ones. Thus the natural fluctuations about equilibrium states (both under adiabatic and non-adiabatic conditions), nonequilibrium stationary states and the general nonequilibrium states have been discussed, using the deductions thereof, the mathematical expressions for probability of achieving nonequilibrium state on account of natural fluctuations about equilibrium and nonequilibrium states have been rationalized. These deductions also help in understanding the origin of replicas of a given system in a Gibbsian ensemble. These findings are crucial for developing an irreversible thermodynamic framework and also for evolving corresponding statistical mechanical description. The minimum time scale of θ_therm when imposed on the statistical mechanical description, generates the corresponding thermodynamic description and hence the application of this condition is indeed, an act of imposing the dictates of the laws of thermodynamics on the microscopic level of mathematical expressions.

31 ref

019900   Yadav S;Bandyopadhyay A K;Gupta V K;Gupta A C (National Physical Lab, , Dr.K S Krishnan Marg, New Delhi-110 012) : Traceability and stability of hydraulic transfer pressure standard upto 140 MPa. MAPAN 2002, 17(1), 3-10.

Traceability is a concept of establishing a valid calibration of a measuring instrument or a measuring standard by a step by step comparison with better national/international standards. Also, the stability of the metrological characteristics with minimum drift over a long period of use, is one of the important features of the standard to schieve objective evidences of having faith and confidence about the quality of measurements made by that standard. Most of the hydraulic instruments received by NPL, India for calibration are in the pressure range of atmospheric pressure to 120 MPa. Therefore, in order to build-up and maintain confidence in the measurements in the pressure range upto 140 MPa, an extensive in-house intercomparison exercise is carried out on a national transfer pressure standard, designated as NPL140MPA herein thereafter by cross-floating it against three other national hydraulic pressure standards, designated as NPL200MPA, NPL100MPN and NPL100MPA. Describes the results thus obtained on the metrological characteristics of NPL140MPA i.e. zero pressure effective area (A_o), distortion coefficient (b) and measurement uncertainly associated with pressure measurement in this in-house intercomparison exercise. The traceability, compatibility and stability of the metrological characteristics thus obtained are established by comparing the values with the values obtained during international key comparisons sponsored by BIPM during 1990, in-house comparison carried out during 1997 and data provided by the manufacturer during 1987. The metrological characteristics thus obtained establish an excellent agrrement with ± 14 x 10^-6 over a period of 13 years.

7 illus, 1 table, 11 ref

019899   Suryavanshi B M;Mehrotra S C (Physica Dep, Institute of Science, Nagpur-440 001) : Dielectric behaviour of binary polar liquid mixtures in dilute solutions of benzene at microwave frequency. Asian J Chem 2003, 15(2), 1167-9.

Dielectric relaxation behaviour of two binary systems, viz., 2-aminopropane + nitrobenzene and 2-ethoxyethanol + pyridine in dilute solutions of benzene have been studied at 9.54 GHz and at room temperature. A concentration variation method of Gopala Krishna is used to determine the experimental relaxation time ((F128><116>) of the systems. A theoretical treatment of Madan is used to determine ((F128><116>) values. A theoretical relation for determining ((F128><116>) values for non associated behaviour of binary mixture is also proposed. The results are interpreted in terms of intermolecular interactions of the relaxing groups in the mixture. The ((F128><116>) values determined from the proposed theoretical equation are consistent with the values determined from the Maddan's relation.

^ssc1 table, 10 ref

019898   Srivastava S K;Vishwakarma B R (Physics Dep, Govt P G College, Ambikapur) : Cross-polarization and attenuation of microwave/millimeter wave propagation in storm layer containing sand, silt and clay as dust constituents. J Instn Engrs-Pt ET 2003, 84(July) , 42-6.

Theoretical investigation has been carried out to evaluate the cross-polarization and attenuation of microwave/millimeter wave from the layer of three main constituents of storm ie, sand, silt and clay. The concept of differential attenuation and phase shift has been utilized to quantify the cross-polarization and attenuation. It has been found that differential attenuation, depolarizing angle and cross-polarization depend upon frequency and visibility. Differential attenuation of microwave signal is greater in sand particles than silt and clay particles. At higher visibility differential attenuation will be lower and vice versa.

5 illus, 13 ref

019897   Srinivas M D (NO, Centre for Policy Studies, 27, Rajasekaran Street, Mylapore, Chennai-600 004) : Optimal entropic uncertainty relation for successive measurements in quantum information theory. Pramana J Phys 2003, 60(6), 1137-52.

Derives an optimal bound on the sum of entropic uncertainties of two or more observables when they are sequentially measured on the same ensemble of systems. This optimal bound is shown to be greater than or equal to the bounds derived in the literature on the sum of entropic uncertainties of two observables which are measured on disticnt but identically prepared ensembles of systems. In the case of a two-dimensional Hilbert space, the optimum bound for successive measurements of two-spin components, is seen to be strictly greater than the optimal bound for the case when they are measured on distinct ensembles, except when the spin components are mutually parallel or perpendicular.

1 illus, 1 tables, 23 ref

019896   Singhal R P (NO, National Physical Laboratory, Dr K S Krishnan Marg, New Delhi-110 012) : ISO/IEC 17025 viz-a-vis ISO/IEC guide 25 - a review. MAPAN 2002, 17(4), 165-71.

Discusses the new standard ISO/IEC 17025 : 1999 which has replaced ISO/IEC Guide 25: 1990. An attempt has been made to review this clause by clause and highlight new features of ISO/IEC 17025 in comparison to ISO/IEC Guide 25. The compatibility with ISO 9001 and ISO 9002 that are relevant to the scope of testing and calibration laboratories are also discussed.

^iia1 table, 6 ref

019895   Singh Y P (National Physical Laboratory, , Dr K S Krishnan Marg, New Delhi-110 012) : Evaluation of expression of uncertainty in calibration of liquid-in-glass thermometers. MAPAN 2002, 17(1), 11-8.

Describles the evaluation of uncertainty in the measurement of temperature by universal (new) method in the calibration of liquid filled glass thermometers at the confidence level of approximately 95.45%. The calculation and expression of uncertainty has been supported by a case study on a Hg-filled glass thermometer calibrated against a standard platinum resistance thermometer (SPRT).

10 ref, 5 ref

019894   Sharma R;Ojha V N;Kothari P C (National Physical Laboratory, , Dr K S Krishnan Marg, New Delhi-110 012) : ISO/IEC 17025 vs ISO guide 25 : assessors' responsibility. MAPAN 2002, 17(2), 75-80.

ISO/IEC 17025 : 1999 gives the requirement for evaluation of competence of testing and calibration laboratories. It replaces ISO/IEC Guide 25. An attempt has been made to highlight new features of ISO/IEC 17025 in comparison to Guide 25. The added responsibilities of assessors for the testing and calibration laboratories have been highlighted.

7 ref

019893   Sen Gupta A;Hanjura A K (National Physical Laboratory, , Dr K S Krishnan Marg, New Delhi-110 012) : Design and development of high resolution frequency counter for AC mains. MAPAN 2002, 17(1), 19-23.

A frequency with a resolution of 0.001 Hz has been designed and developed for measuring the AC mains frequency. Measurements are made every second. The frequency values can be read from a front panel digital display and are also provided in RS232C protocol on a output port.

1 illus, 2 ref

019892   Saxena A K;Mohd Saleem;Rao S U M;Singhal R P (National Physical Laboratory, , Dr K S Krishnan Marg, New Delhi-110 012) : Interlaboratory proficiency testing in capacitance measurement for NABL accredited laboratories - 2001/02. MAPAN 2002, 17(4), 157-64.

Reports the results of proficiency testing in capacitance measurement. It was conducted for the NABL accredited laboratories, under the MoU between NPL and NABL. A 100 pF capacitor was used as an artifact to assess the measurement capability of participating laboratories. Thirteen NABL accredited laboratories have participated in this programme during May 2001 to April 2002. This programme was conducted in two phases. NPL, New Delhi, acted as a reference laboratory as well as coordinated the programme. It was the first proficiency testing programme in capacitance measurement conducted within the country.

4 illus, 1 tables, 8 ref