003170   Yadav O P;Sansanwal P K (Dep Chem, CCS Haryana Agrl Univ, Hisar 125 004) : Quenching antiquenching effect of some organic compounds on luminescence of CdS colloids. Indian J Chem-Sect A 2003, 42(11), 2746-8.

Effect of some amines and phenol on luminescence intensity of Cds colloids has been studied. The additives with electron donors groups (-NH₂ or -OH) bind to lower energy trap sites which are involved in non-radiative decay, causing enhanced fluorescence.

^ssc2 illus, 9 ref

003169   Syam D;Chatterjee A R (Dep of Phys, Presidency College, Calcutta-700 073) : The Harmonic Analyser - some problems and how to overcome some of them. Phys Educ 2001, 18(2), 91-7.

Fourier analysis of a complicated periodic electrical waveform may be performed by means of series resonant or parallel resonant LCR circuits. Such devices are generally called Harmonic Analysers. Operation of a simple parallel resonant Harmonic Analyser has been analysed and it has been explained. Why it does not give the theoretically expected values of the ratios of the amplitudes of the various harmonics. It is shown that the theoretical and the experimental estimates of the rms values of the signal voltages are in much better agreement.

^iia2 illus, 5 tables

003168   Subramaniam T K (Dep of Physics, Rajalakshmi Engineering College, Thandalam, Chennai-602 105) : Spectroscopic study of the molecular bands of HgCl : identification of the B(<. Indian J Phys-Pt B 2003, 77(5), 537-43.

Thirty molecular HgCl bands are recorded using the laser optogalvanic technique in the B ← X transition <40>² Σ⁺ ←² Σ⁺<41> in 563 nm to 633 nm region. Many of these bands have been observed for the first time. The bands are vibrationally analysed and the isotopic heads fit in well with the theoretically estimated isotopic shifts. Molecular constants have been derived from the analysis.

2 illus, 4 tables, 20 ref

003167   Singh M K;Behari J (NO, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110 067) : Sono-chemical treatment of sewage sludge and organic pollutants- a review. J pure appl Ultrasonics 2003, 25, 88-100.

Sludge is the by-product of wastewater treatment. It contains multitude of pollutants. The presently available treatment technologies are not free from drawbacks and less efficient as well. In the study, sludge characteristics (sludge generation process, type of sludge, components and impact on environment) and its conventional and ultrasonic treatment methods, its mechanism, and sonochemistry to treat sludge and various hazardous organic pollutants is discussed. This may lead to optimisation of ultrasonic treatment of wastewater and exploring novel alternative technologies.

5 illus, 63 ref

003166   Singh D;Yadav R R (Department of Physics, University of Allahabad, Allahabad-211 002) : The thermal conductivity and ultrasonic absorption in dielectric crystals. J pure appl Ultrasonics 2003, 25, 82-7.

Ultrasonic absorption and other associated parameters have been evaluated in AgCl, LiF and MnO along different directions as a function of higher temperatures and also calculated the second and third order elastic constants of these materials for the evaluations. The results are compared with experimental values. It is concluded that the lattice thermal conductivity played an important role in temperature dependence of the ultrasonic absorption in these dielectrics.

10 illus, 3 tables, 20 ref

003165   Singh D;Sukhmal Chand;Anwar M;Patra D D (NO, Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226 015) : Effect of organic and inorganic ammendments on growth and nutrient accumulation by isabgol (Plantago ovata) in sodic soil under greenhouse conditions. J med aromatic Pl Sci 2003, 25(2), 414-19.

A pot experiment was conducted during the year 1997-98 at CIMAP, Lucknow to evaluate the effect of single and combined application of organic(Mentha distillation waste applied ≅ 15 t ha^-1; MS₁₀₀ and 7.5 t ha^-1; MS₅₀ and inorganic amendments), (gypsum at 0, 25 and 50 % of gypsum requirement; Gr₀, GR₂₅ and GR₅₀) on growth and nutrient uptake by different cultivars of isabgol, (Plantago ovata Forsk), viz., Niharika, 30-30 D and Commercial in sodic soil. Plant height and dry matter (grain ÷ straw) yield of isabgol increased by 2.3 to 17.8 and 151.0 to 330.58 %, respectively over control, due to application of different combinations of organic and inorganic amendments. N,P,K,Na and Mg uptake were highest in T₃ (receiving 50<37 of gypsum requirement, GR₅₀) which was about 5.8, 4.3, 3.7, 2.9 and 4.7 times higher as compared to that in control, respectively. K:Na and Ca:Na ratios were maximum in T₄ receiving 25% of gypsum requirement (GR₂₅) ÷ Mentha spent <64> 7.5 t ha^-1 (MS₅₀). Available N and P in sodic soil increased with application of organic and inorganic amendments in different proportions.

3 tables, 16 ref

003164   Singal S P (NO, , Formerly Scientist, Head Acoustics, National Physical Laboratory, New Delhi-110 012) : A historical review of acoustic propagation in atmospheric air: introduction to acoustic sounding (SODAR). J pure appl Ultrasonics 2003, 25, 65-81.

History of propagation of acoustic waves in the atmospheric air has been traced. Starting with rudimentary information about the science of sound with the Greek philosophers around 600 BC, the subject has developed enormously during the last four centuries, so much so, that understanding of the subject has grown quite deep by now. Sound ranging, used effectively in World War I, had been possible due to precise measurements of sound velocity in the atmospheric air. Viscosity and thermal conduction are now termed the classical attenuation parameters of propagation of sound in air, while intra-molecular relaxation, ground absorption and turbulence are the modern concepts that truely define attenuation characterstics of air. Refraction due to the presence of wind and temperature gradients in the atmosphere has explained the formation of shadow zones and propagation of sound over long distances. Scattering of acoustic wavws due to turbulence (in-homogeneities present in the atmospheric air) developed by variations inwind velocity, humidity and lapse rate, have found application in determining the meteorological structure and weather features of the atmospheric boundary layer. The technique used for this process has been called acoustic sounding or Sodar, and has potential application to monitor hazardous situations in aviation, microwave communication and air pollution.

8 illus, 1 table, 104 ref

003163   Sharma R C;Gangta S (Dep of Mathematics, Himachal Pradesh University, Shimla-171 005) : Stability of superposed viscous-viscoelastic (Walters B') fluids in porous medium in hydrodynamics and hydromagnetics. Indian J Phys-Pt B 2003, 77(5), 529-32.

The instability of the plane interface between two superposed viscous and viscoelastic (Walters' B′) fluids in porous medium, in hydrodynamics and hydromagnetics, has been studied. The effect of a variable horizontal magnetic field is also considered separately. For the potentially stable arrangement, the system is stable or unstable according as v′ <60> or <62> k₁ <132> ∈ α₁. The magnetic field has stablizing effect and completely stabilizes certain wavenumber band k <62> k<42> (if v′ <60> k₁ ∈ α₁), which was always unstable in the absence of magnetic field, for the potentially unstable arrangement. However, the system is always unstable for the wave number band k <60> k<42> or if v′ <62> k₁ <132> ∈ α₁.

1 illus, 4 ref

003162   Shandilya R P;Varma P;Tiwari M S (Dep of Physics, Dr. H S Gour University, Sagar-470 003, Madhya Pradesh) : inetic Alfven wave in the magnetized dusty plasma-particle aspect analysis. Indian J Phys-Pt B 2003, 77(5), 553-9.

The effect of charged dust grain is examined on the field-aligned current, perpendicular current (with respect to B_o), dispersion relation and growth rate for the kinetic Alfven wave with bi-Maxwellian distribution function. It is found that negative charge residing on dust grain, enhances the wave frequency and growth rate ; however , the frequency obtained is smaller to that of the wave supported by ions and electrons only. The effect of charge concentration on dust grain is found to increase the perpendicular current and to decrease the parallel current to maintain the current continuity. The dust particle density reduces the wave frequency and the growth rate. The present calculation suggests that the presence of duct particles in auroral region may change the scenario of magnetosphere-ionosphere coupling processes and related phenomena.

4 illus, 10 ref

003161   Sen A;Chaplot S L;Mittal R (Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085) : Structural and dynamical consequences on various high-pressure phase transitions in laser host fluoroscheelites LiYF₄ and LiYbF₄. Curr Sci 2003, 85(7), 1045-9.

Computer simultations of pressure-induced phase transitions in LiYF₄ and LiYbF₄ have been carried out using complimentary tecniques of molecular dynamics (MD) and lattice dynamics. The MD simulations at a constant temperature of 300 K with increasing pressure reveal structural changes at around at 5 and 15 GPa and the crystallographic space groups of the new structures. The lattice dynamics calculations are then conveniently used to derive the vibrational spectra and the free energies and its consequences on the thermodynamic stability of the new phases.

6 illus, 23 ref

003160   Samuel E J J;Mohan S (NO, Vellore Inst. of Technology, Vellore-632 014) : Vibrational spectra and analysis of 2-methyl para benzoquinone. Indian J Phys-Pt B 2003, 77(5), 575-8.

The FTIR and FT Raman spectra of 2-methyl para benzoquinone have been recorded. The observed frequencies were assigned to various modes of vibrations on the basis of normal coordinate calculations, assuming C, point group symmetry. The potential energy distribution assciated with each normal mode was also reported. The assignment of fundamental vibrations agree well with the calculated frequencies.

2 illus, 1 table, 23 ref

003159   Roshan Lal;Mishra S C (Dep of Physics, Kurukshetra University, Kurukshetra-136 119, Haryana) : Integrability of two coupled oscillators using complex coordinates. Indian J Phys-Pt B 2003, 77(5), 567-70.

A general method is used for finding the second constant of motion of fourth order in complex coordinates for two dimensional classical systems. A general potential equation is obtained which provides a large class of second constant of motion for two dimensional systems. However, it has been observed that the arbitrary constants are chosen in such a way that system becomes exactly integrable.

12 ref

003158   Rao K R (NO, , 'Gokula' 29/2, 11th Cross, 3rd Main, Malleswaram, Bangalore 560 003) : Neutron scattering, quantum entanglement and chemical formula of water. Curr Sci 2003, 85(7), 848-50.

^ssc2 illus, 8 ref

003157   Ramrakhiani M (Dep of Post-Grad Studies and Res in Phys, Rani Durgavati Vishwa Vidyalaya, Jabalpur-482 001) : Fundamentals of light emitting diodes. Phys Educ 2001, 18(2), 99-108.

Various materials used for light emitting diodes of different colours are discussed. The double heterostructure LEDs and use of quantum wells and superlattices for enhancement of the performance have been highlighted. Light emitting devices based on conjugated polymers are also described.

^iia9 illus, 2 tables, 5 ref

003156   Ramanjappa T;Rajagopal E;Manhara Murthy N (Department of Physics, Sri Krishnadevaraya University, Anantapur-515 003) : Excess thermodynamic fluctuation parameters of binary mixtures of acetonitrile, benzene and dimethy-formamide at 298.15 k. J pure appl Ultrasonics 2003, 25, 101-4.

The parameters characterizing thermodynamic fluctuations namely mean square fluctuations of pressure <60>(ΔP)²<62>, temperature <60>(ΔT)²<62>, number of molecules in a given volume <60>(ΔN/N)²<62> and the correlation function of pressure and temperature fluctuations <60>(ΔP)(ΔT)<62> in the binary mixtures of CH₃CN + C₆H₆, C₆H₆ + HCON(CH₃)₂ and CH₃CN + HCON(CH₃)₂ at 298.15 K have been evaluated using the data on ultrasonic velocity, density, molar heat capacity at constant pressure and thermal expansion coefficient. The corresponding excess functions have been evaluated considering that the ideal values are additive on mole fraction basis. The variations of <60>(ΔP)²<62>^E, <60>(ΔT)²<62>^E, <60> (ΔN/N)² <62>^E and <60>(ΔP)(ΔT)<62> ^E with the mole fraction of the first component are found to exhibit extrema at intermediate concentrations. The results are explained in the light of modification of the structure of pure liquids as a result of mixing with the other and stability of the structure formed in the mixtures against the various thermodynamic fluctuations present in the liquid state.

4 illus, 7 ref

003155   Nath M;Teredesai P V;Muthu D V S;Sood A K;Rao C N R (Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore-560 064) : Single-walled carbon nanotube bundles intercalated with semiconductor nanoparticles. Curr Sci 2003, 85(7), 956-60.

Nanoparticles of CdSe, CdS and ZnSe have been incorporated in the inter-tubular gaps of single-walled carbon nanotube (SWNT) bundles. Electron microscope, X-ray diffraction (XRD), electronic spectroscopy and Raman studies have been employed to characterize these systems. The lengths of the intercalate inside the bundles could be varied by changing the reaction conditions. Electronic absorption and photoluminescence studies from the semiconductor intercalates show the expected blue-shift with respect to the corresponding bulk samples in CdS and ZnS samples. The SWNT lattice is expanded on incorporating CdSe as confirmed by XRD in the low-angle range. The expansion in the lattice is also corroborated by the Raman measurements which show a considerable red-shift for both the radial and the tangential modes of the SWNT signal, thus signifying an increase in the van der Waals gap between the tubes in the bundle. The red shift of the Raman signal is due to the decrease in the inter-tube interactions as well as due to doping effects.

6 illus, 14 ref

003154   Mahesh T S;Sinha N;Ghosh A;Das R;Suryaprakash N;Levitt M H;Ramanathan K V;Anil Kumar (Dep of Physics, Indian Institute of Science, Bangalore-560 012) : Quantum information processing by NMR using strongly coupled spins. Curr Sci 2003, 85(7), 932-44.

The enormous theoretical potential of quantum information processing (QIP) is driving the pursuit for its practical realization by various physical techniques. Currently, nuclear magnetic resonance (NMR) has been the forerunner by demonstrating a majority of quantum algorithms. In NMR, spin-systems consisting of coupled nuclear spins are utilized as qubits. In order to carry out QIP, a spin-system has to meet two major requirements: (i) qubit addressability and (ii) mutual coupling among the qubits. It has been demonstrated that the magnitude of the mutual coupling among qubits can be increased by orienting the spin-systems in a liquid crystal matrix and utilizing the residual dipolar couplings. While utilizing residual dipolar couplings may be useful to increase the number of qubits, nuclei of the same species (homonuclei) might become strongly coupled. In strongly coupled spin-systems, spin lose their individual identity of being qubits. It has been proposed that even such strongly coupled spin-systems can be used for QIP and the qubit manipulation can be achieved by transition-selective pulses. Experimental preparation of pseudopure states, creation of maximally entangled states, implementation of logic gates and implementation of Deutsch-Jozsa (DJ) algorithm in strongly coupled 2, 3 and 4 spin-systems have been demonstrated. The energy levels of the strongly coupled 3 and 4 spin-systems were obtained using a Z-COSY experiment.

16 illus, 4 tables, 48 ref

003153   Maalej A;Azri C;Medhioub K;Rosset R (Departement de Physique, Faculte des Sciences de Sfax(FSS), 3018, Sfax, Tunisia) : Numerical modeling for the study of ozone transport in sea-breeze circulations at Sfax (Tunisia). Indian J Phys-Pt B 2003, 77(5), 503-12.

An ozone pollution episode typically at the mesoscale is studied for the summer period 14-15 July 1995 in the region of Sfax (Tunisia) which is submitted to strong sea-breeze circulations. At such regional scales, sea-breeze circulations are key dynamic features in the processing of natural and anthropogenic emissions in coastal, urban and industrial areas and inland, rural areas. The role of moving sea-breeze fronts on air pollution in the region of Sfax is investigated with the use of mesoscale model Meso-NH-C(Mesoscale Non-Hydrostatic Chemistry model)in which the meteorological model Meso-NH is coupled on-line with a chemistry module. Various assumptions are presented for Meso-NH-C: e.g. compact of the chemical scheme to reduce the computational costs and the definition of procedure to fill in the lack of emmission inventory data. Sensitivity studies about the impact of sea-breeze fronts on the tranport and diffusion of ozone at coastal and inland areas of Sfax are presented. The Meso-NH appears to realistically simulate the sea-breeze circulations. Sea-breeze front penetration inland followed by its merging and interaction with strong continental convection caused an ozone dispersion in the period studied.

13 illus, 4 tables, 27 ref

003152   Kedar Singh;Saxena N S;Thomas S (Condensed Matter Physics Laboratory, Dep of Physics, University of Rajasthan, Jaipur-302 004) : Temperature dependence of thermophysical properties of untreated glass oil-palm-fibre reinforced phenolformaldehyde composites. J scient ind Res 2003, 62(9), 903-8.

Thermophysical properties such as, effective thermal conductivity (λ_e) and effective thermal diffusivity (χ_e) of untreated reinforced phenolformaldehyde with different weight per centages of oil-palm-fibre (x) are measured simultaneously using the transient plane source (TPS) technique between 80 to 120°C. The composites investigated contain 20, 30 and 50 weight percentage of oil-palm-fibre. The experimental results at different weighted composites show that there is variation in λ_e and χ_e in this temperature range. However, a maximum value of λ_e and χ_e is observed at 100°C, which lies in the vicinity of glass transition temperature (T_g) of this composites. Efforts are also made to predict the weight percentage of oil-palm-fibre (OPF) and temperature dependence of λ_e and χ_e through the development of an empirical model. Theoretical predicted values of λ_e and χ_e for these composites are in agreement with experimental results over the entire range of temperature for investigations.

7 illus, 26 ref

003151   Kalyana Raman S B;Vasantharani P;Selvakumari P (Dep of Physics, Annamalai University, Annamalainagar-608 002, Tamil Nadu) : Computation of acoustical parameters of pure liquids through simple C-program. Indian J Phys-Pt B 2003, 77(5), 571-4.

Experimentally determined ultrasonic velocity, density and viscosity have been used to compute various acoustical parameters such as adiabatic compressibility, free length, free volume, internal pressure, etc. These parameters provide valuable information about the various properties of liquids and liquid mixtures. A compact C-program to compute all the important acoustical parameters of pure liquids have been presented.

1 table, 16 ref

003150   Hussaini A;Krishnan P;Abhishek V;Siddiqi O (National Centre for Biological Sciences, Tata Institute of Fundamental Research, P.B. 6501, GKVK Campus, Bangalore-560 065) : Possible explanation for the extended UV emission lines from helium-hydrogen plasma. Curr Sci 2003, 85(7), 856-7.

^ssc1 illus, 3 ref

003149   Harun S W;Tamchek N;Ahmad H (Photonics Laboratory, Dep of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia) : Gain clamped L-band EDFA with injection of C-band ASE. Indian J Phys-Pt B 2003, 77(5), 545-7.

The effect of injecting conventional band (C-band) amplified spontaneous emission on the performance of long wavelength band erbium-doped fiber amplifier (L-band EDFA) is demonstrated. It uses a circulator and broadband fiber Bragg grating (FBG) to route C-band ASE from a C-band EDFA. Injection of a large amount of ASE reduces and clamps the small signal gain with a small noise figure penalty compared with those without the ASE injection. With the ASE injection, the gain of the amplifier is clamped at 15.2dB from -40 ro -10dBm with a gain variation of less than 0.3dB. The saturation power is also increased from -8dBm to 2dBm. Those results show that the ASE injection technique can be used for gain clamping in L-band EDFA.

5 illus, 4 ref

003148   Godwal B K;Modak P;Verma A K;Gaitonde D M;Rao R S (High Pressure Physics Division, Bhabha Atomic Research Centre, Mumbai-400 085) : First principles theories and MgB₂ at ambient and high pressures. Curr Sci 2003, 85(7), 1050-6.

MgB₂, the recently descovered high temperature superconductor, is considered from the perspective of first principles electronic structure and phonon calculations. The discrepancies in the estimated quantities related to its superconductivity vis-a-vis their experimental values, and resons thereof are discussed. It has been predicted that hole-doped light-atom compound MgB₂C₂ delete is a strong canditate for high temperature superconductivity. Anomalous high pressure behaviour seen in MgB₂ near 18 GPa is discussed, and it has been demonstrated for the first time by calculating the high pressure electronic structure with frozen-in phonon-mode displacement of atoms, that phonon-assited electronic topological transition is the probable cause of the anomaly.

6 illus, 34 ref

003147   Geetha;Rakkappan C (Dep of Physics, Annamalai University, Annamalai Nagar-608 002) : Ultrasonic studies on solutions of hydroxy propyl methyl cellulose phthalate in alcohols and acetone mixture. Indian J Phys-Pt B 2003, 77(5), 525-8.

Ultrasonic velocity, density and shear viscosity have been measured for solutions of hydroxy propyl methyl cellulose phthalate (PMCP) in methanol, ethanol, propanol and n-butyl alcohols with Acetone mixture (1:1). The ultrasonic velocity and absorption data are presented in 303 K. By taking measurements at several concentrations of each solutions, information about the molecular intraction between the solute and event molecules was obtained.

2 tables, 17 ref

003146   Dongare M B;Mane T B;Jadhav D B (Department of Physics, Shivaji University, Kolhapur-416 004, Maharashtra) : Total column density of ozone at coastal season Devgad (16×24'N, 73×26'E) measured using portable visible spectrometer. Indian J Phys-Pt B 2003, 77(5), 513-7.

Ozone measurements are carried out at coastal stations Devghad (16×24'N, 73×26'E) by measuring the solar spectral extinction in the Chappuis band. The measurements are carried out during the months December, January, February, March and April from the year 1996 to 1999. The monthly mean total ozone shws a definite increasing trend from the month of December to April. No significant change is observed in the average value of the total ozone calculated for five months during the years 1996 to 1999.

5 illus, 1 tables, 28 ref

003145   Dattagupta S (NO, S.N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata-700 098) : Dissipation. Curr Sci 2003, 85(7), 961-8.

The interaction of a physical system with its environment generally leads to dissipation. For, example, a large particle immersed in a liquid experiences frictional drag and velocity fluctuations, both resulting from repeated impact of the fluid particles. Dissipation in the presence of cooperative effects in strongly interacting systems which exhibit physical phenomena like pattern formation, phase-ordering, domain growth kinetics, etc have also been discussed. Quantum dissipation and its influence on tunnelling, Brownian motion and crossover from coherence to decoherence have been discussed.

7 illus, 30 ref

003144   Chidambaram R;Sikka S K (NO, , Principal Scientific Adviser to the Government of India, Vigyan Bhawan Annexe, Maulana Azad Road, New Delhi-110 011) : Neutron crystallography- Then and now. Curr Sci 2003, 85(7), 871-7.

Neutron crystallography began to be employed at the Bhabha Atomic Research Centre(BARC), Trombay Mumbai in the early sixties. At that time, the Technique, at the BARC as well as elsewhere, was in a nascent state, with emphasis on building of instruments and development of crystallography software. Over the years, the Trombay group kept pace with the advancements in other parts of the world and employed neutron diffraction to get answers to a variety of important problems. Advances of the method over the years have been reviewed and its applications have been pointed out. In particular the phase problem in neutron crystallography and its contributions for hydrogen bonding, biological macromolecular structures and high pressure science have been discussed.

^iia5 illus, 5 tables, 61 ref

003143   Bhardwaj V;Bhatnagar D;Saini J S;Sharma K B (Microwave Laboratory, Dep of Physics, University of Rajasthan, Jaipur-302 004, Rajasthan) : A right isosceles triangular microstrip antenna in warm ionized plasma medium. Indian J Phys-Pt B 2003, 77(5), 579-82.

The radiation properties of a right isosceles triangular microstrip antenna (RITMA) are investigated theoretically in warm ionized plasma medium. The modal expansion technique with vector potential approach is applied to determine the radiation behaviour of this antenna in free space while hydrodynamic theory is applied to compute its performance in plasma medium. This theoretical study is carried out in TM₁₁ mode of excitation of antenna and a significant variation in radiation conductance and radiation efficiency of RITMA structure with the variation in the ratio of plasma to source frequency (ω_p / ω) is recorded. For better understanding, the computed E and H plane radiation patterns in plasma medium are compared with theoretically obtained free space patterns.

4 illus, 2 tables, 5 ref

003142   Badruddin;Singh Y P (Department of Physics, Aligarh Muslim University, Aligarh-202 002, Uttar Pradesh) : Forbush decreases in cosmic radiation : effects of solar flares associated with type IV radio bursts and with different field orientations at flares sites. Indian J Phys-Pt B 2003, 77(5), 497-502.

The large-scale magnetic fields at flare-sites are considered and relative effectiveness of flares with different field orientations on interplanetary parameters and on characteristic features of Forbush decreases are discussed. Differences in cosmic ray modulating efficiency of flares with southward/ northward directed magnetic fields and those associated / not-associated with type-IV radio bursts have been found. Forbush decreases are more frequently associated with southward flares as compared to northward flares. Most of the flares associated with large increase in IMF intensity and/or solar wind speed and producing large amplitude Forbush-like dicreases are also associated with type-IV radio bursts. The results are disscused in the light of models of Forbush decreases including drift effects. An explanation is given to account the observational results.

7 illus, 1 table, 40 ref

003141   Arakeri V H (Dep of Mechanical Engineering, Indian Institute of Science, Bangalore-560 012) : Sonoluminescence and bubble fusion. Curr Sci 2003, 85(7), 911-6.

Sonoluminescence (SL), the phenomenon of light emission from nonlinear motion of a gas bubble, involves an extreme degree focusing. The conditions within the bubble during the last stages of the nearly catastrophic impolsion are thought to parallel the efforts aimed at developing inertial confinement fusion. A limited review on the topic of SL and its possible connection to bubble nuclear fusion is presented. The emphasis is on looking for a link between the various forms of SL observed and the severity of bubble colapse or impolsion. A simple energy analysis is also presented to enable the search for an appropriate parameter space and an experimental technique for achieving energy densities required for triggering fusion reactions within the bubble.

4 illus, 1 table, 41 ref

003140   Anil Kumar C P;Venugopal C;George B;Renuka G (School of Pure & Applied Physics, Mahatma Gandhi University, Priyadarshini Hills, Kottayam-686 560, Kerala) : Linear instabilities in multi-ion plasmas. Indian J Phys-Pt B 2003, 77(5), 561-6.

Stability of ion-cyclotron waves in multi-ion plasms consisting of electrons, positively and negatively charged oxygen ions and hydrogen ions are examined by simulations. In order to identify the modes in a mixed plasma and to gain physical insight into the nature of the instability, cold plasma theory is used, while the warm plasma theory accounts for finite temperature effects. The expression for the frequencies of lower hybrid and ion-ion hybrid modes are derived and solved by numerical methods. From the simulation studies it is concluded that lower hybrid mode is a weakly unstable mode while the ion-ion hybrid mode is almost freely propagating.

5 illus, 20 ref

003139   Alex M;Prasad D N;Prasad K R;Kataria S K; Athavale S N;Pappachan A L;Subramanian C;Grover A K;Suri A K (Materials Processing Div, Bhabha Atomic Research Centre, Mumbai-400 085) : Indigenous development of Gamma compensated boron lined neutron chambers. J scient ind Res 2003, 62(11), 1057-62.

ϒ-compensated boron-lined ionisation chambers are indigenously developed for neutron monitoring applications in reactors using inexpensive and easily available polyether ether ketone (PEEK) insulating material as an alternative to alumina. The chamber has overall diam of 8.5cm and 31.5 cm length. 0.7g of indigenously developed 40.5 per cent enriched boron is dip coated on the electrodes. The chamber has neutron sensitivity of 5.5fA/nv and an average ϒ-compensation factor of 4 per cent. The performance of the neutron detector is compared with similar detector with alumina discs. The use of suitably shaped PEEK inserts at the ends of tje electrodes eliminates extra-cameral volume. This results in more uniform electric field and well-developed sensitive volume between the electrodes. As a result the chamber with PEEK insert requires 50V to saturate as compared to 100V in the case of the chamber with alumina discs when exposed to thermal neutron flux to 10⁸nv. The variation in ϒ-compensation factor reduces from ± 9 to ± 4.5 per cent between 300 to 3150 R/h. The indigenous development of the detector helps avoid long-term dependence on imports and also saves substantial amount of foreign exchange.

7 illus, 3 tables, 7 ref

003138   Agarwal Y K;Verma P K (Dep of Physics, Aligarh Muslim University, Aligarh-202 002, Uttar Pradesh) : Fundamental frequencies of 2-iodo- 5 - nitro toluene from FT - Raman and FT - IR spectra. Indian J Phys-Pt B 2003, 77(5), 549-52.

FT-Raman and FT-IR spectra of 2 - iodo-5-nitro toluene have been recorded in the region 50-500 cm^-1 and 400-4000 cm^-1 respectively. The vibrational analysis is carried out in terms of fundamentals. The probable mode of vibrations have been assigned assuming C symmetry.

1 table, 33 ref

003137   Adgaonkar C S;Chaudhary M P (Dep of Electronics, Inst of Sci, Nagpur-440 001) : Determination of elastic constants of wood and metals using optical (Cornu's) method (A Modified Experiment). Phys Educ 2001, 18(2), 109-14.

A well known Cornu's method used in optics for the determination of Young's modulus (Y), bulk modulus (K), rigidity modulus (η) and Poisson ratio (σ) for glass plate is used, after suitable modification, for the determination of these constants for wood, aluminium and copper. For obtaining fringes the wood surface was covered with cello tape whereas the metal surfaces were smoothened using No 120 emery paper. The values of these parameters for these samples agree well with the literature values. The method is accurate and is well suited for undergraduate solid state physics laboratory as well as for the research work.

6 illus, 1 table, 7 ref

002348   Yazar H R (Phys Dep, Kirikkale Univ, Fac of Arts and Sci, Kirikkale-Turkey) : Calculation of some nuclear properties in <. Bull pure appl Sci-Sect D 2003, 22(1), 69-73.

For doubly even nuclei ^164-166Er, Energy levels, Deformation parameters β₀, β₂ and Quadrupole moments Q₀, Q₂⁺ and the electric quadrupole transition probability B(E2) have been considered between the ground state and first excited 2' state. These nuclear properties are calculated using the proton-neutron interacting boson approximation (IBA-2). The results obtained for ^164-166Er are reasanably good agreement with previous experimental and theoretical values.

1 table, 21 ref

002347   Yadav S;Sanjay Kumar (University Dep of Physics, L.N. Mithila University, Darbhanga, Bihar) : Effects of electric field on polarons and bipolarons in conjugated polymers. Acta Cienc Indica-Phys 2003, 29(3), 317-20.

The charge transport on a single conducting polymer chain has been investigated. The dynamics of polarons and bipolarons has numerically been studied on SSH and PPH model extended to include an external electric field and a Brazovskii-Kirova symmetry breaking interaction. The time dependent unrestricted Hartree Fock approximation has been used. It is found that dynamical effects do not reverse the stability relation between polarons and bipolarons. As the electric field intensity gets stronger the moving polarons structure is destroyed faster than the structure of moving bipolarons and this effect is reduced with increasing doping concentration. Within the present model it has been shown that the applied electric field and the doping concentration were fundamental in determining the relative prevalence of polarons or bipolarons.

1 illus, 7 ref

002346   Yadav R P;Rathore S (Physics Dep, Govt. P.G. College, Bisalpur, Pilibhit-262 201) : Effect of variable magnetic field on strong cylindrical shocks in a rotating gas. Acta Cienc Indica-Phys 2003, 29(3), 291-308.

Studies the propagation of strong diverging cylindrical shock waves in an ideal and rotating gas, having only the variable azimuthal component of magnetic field. The application of CCW [1-3] and Yadav [4] technique has been used for an initial density distribution ρ₀ = ρ'r^w where, ρ' is the density at the axis of symmetry and w is a constant, while r is the propagation distance. Analytical relations for flow variables for strong shock with strong magnetic field for Freely Propagation (FP) along with effect of overtaking disturbances (EOD), the results accomplished here have been compared with earlier results.

20 illus, 2 tables, 15 ref

002345   Yadav R P;Gangwar P K (Physics Dep, Govt. P.G. College, Bilaspur-262 201) : Freely propagation of spherical converging strong shock wave. Acta Cienc Indica-Phys 2003, 29(1), 51-8.

Neglecting the effect of overtaking disturbances, the Chester-Chisnell-Whitham method has been used to study the propagation of spherical converging strong shock wave in non-uniform medium. Taking the initial density distribution as ρ0 = ρ'r^-ω, where, ρ' is the density at the centre and ω is a constant, analytical relation for shock velocity, pressure, particle velocity and sound velocity immediately behind the shock have been derived. The variation of shock velocity, pressure, particle velocity and sound velocity and sound velocity with propagation distance (r), constant (ω), and adiabatic index (χ) have been given through figures and table. The dependence of pressure, particle velocity and sound velocity on Mach number M has also been shown graphically. It is found that pressure, particle velocity and sound velocity increases as shock propagates in the medium. This agrees with earlier results.

10 illus, 1 table, 16 ref

002344   Yadav A K;Jha R C;Mandal R N (Univ Phys Dep, L. N. Mithila Univ, Darbhanga-846 004) : Study of thermopower of Li at very low temperatures. Bull pure appl Sci-Sect D 2003, 22(1), 39-43.

There is discrepancy between the theory and the experiment of thermopower of alkali metals. Some one considered the idea of phonon-drag contributiono to thermopower to remove this anomaly. According to them, phonon drag component, Sg is very inflective at low temperatures. Theoretical values of thermopower, S of Li at very low temperatures due to election difusion and phonon-drag contribution. These theoretical values have been compared with the corresponding values of thermopower of the experiment. Deviation in have been found them in respect of sign and magnitude both. Modifies the theoretical formula of thermopower due to electronic contribution and with the help of this calculated the thermopower of Li at very low temperatures without the aid of phonon-drag contribution. A good agreement has been found with the nonexpanding experimental values. The electronic contribution of observed thermopower of Li at low temperatures has been separated and it has been compared with the experimental values. A good agreement has been found it has been seen that electrons are the sole contributors to the thermopower of Li. There is no base of phonon-drag contribution to thermopower of Li at very low temperatures.

2 tables, 12 ref

002343   Weigel H (Institute for Theoretical Physics, Tubingen University, Auf der Morgenstelle 14, D-72076 Tubingen, Germany) : Chiral quark model. Pramana J Phys 2003, 61(5), 921-30.

Reviews studies of hadron properties in bosonized chiral quark models for the quark flavor dynamics. Mesons are constructed from Bethe-Salpeter equations and baryons emerge as chiral solitons. Such models require regularization and shows that the two-fold Pauli-Villars regularization scheme not only fully regularizes the effective action but also leads the scaling laws for structure functions. For the nucleon structure functions the present approach serves to determine the regularization presctription for structure functions whose leading moments are not given by matrix elements of local operators. Some numerical results are presented for the spin structure functions.

3 illus, 25 ref

002342   Weber A I (NO, , 3178 East Village DR. Unit Venice FL 34293) : Weber's cataclysmic collision theory. Acta Cienc Indica-Phys 2003, 29(1), 17-22.

2 tables, 34 ref

002341   Vyas B M;Pandey R (Physics Dep, M L Sukhadia University, Udiapur-313 001) : Effect of IMF parameters on F-region drift velocity over low latitude. Indian J Radio Space Phys 2003, 32(3), 142-7.

The effects of various interplanetary magnetic field (IMF) parameters on midnight values of N-S and E-W drift velocity of F-region are studied using the spaced receivers ionospheric drift data collected over a low latitude station, Udaipur (geomagn. lat. 14.5° N), during different seasons of high solar activity period. It is found that both N-S and E-W drift speeds are strongly influenced by the N-S component of IMF. However, the total IMF showed more effect on N-S drift speed as compared to E-W drift. The control of sunward ad E-W components of the drift parameters is found to be insignificant. The control of IMF parameters on drift velocity was more prominent in winter compared to other seasons. The findings have been interpreted in terms of generation of additional electric field at magnetospheric height and its transmission to equatorial ionosphere via polar latitude through a parallel plane transmission line made up of the earth and ionosphere waveguide.

4 illus, 1 table, 27 ref

002340   Vijaya R;Prasad T (Physics Dep, Indian Institute of Technology, Powai, Mumbai-400 076) : Analysis of engineered opals for Photonic band gap property at visible wavelength. Indian J Phys-Pt B 2003, 77(2), 201-5.

Calculations using a modified Transfer Matrix method to study the photonic band gap properties of bare opals of different diameters, different number of layers, sintered opals with filling fractions varying between 0.74 and 1.00, partial and complete coating with semi-conducting GaN and lastly, inverted opals. The two prominent directions of [001] and [111] have been analyzed. Sintering improves the pseudogap and shifts the energy range of its occurrenc, while partial coating gives a larger fall in transmission coefficient than complete coating. Inverted opals in GaN background show a stop band with lower transmission coefficient compared to coated opals due to an improvement in dielectric contrast have been performed. The computational approach with the modified transfer matrix method based on a cubic unit cell in spherical polar corrdinates is easier to implement with comparable accuracy methods to study electromagnetic wave propagation in different directions.

5 illus, 29 ref

002339   Verma P L;Nigam S K (NO, P.G. College, Physics Dep) : Variation in solar wind parameter during the interplanetary shock and magnitude of forbush decrease. Acta Cienc Indica-Phys 2003, 29(1), 31-8.

Studies Forbush decrease ≥4% with interplanetary shocks, solar flare index and jump in solar wind velocity, proton density and thermal speed during the arrival of shocks. Finds that 85.5% Fds are associated with interplanetary shocks. Mostly the Fds are associated with forward shocks and magnitude of Forbush decrease depends upon shock strength. In successive solar maximum the solar flare index remains unchanged but the frequency of occurrence of interplanetary shocks is increasing in each solar maximum.

2 illus, 2 tables, 14 ref

002338   Verma P K;Sinha K P;Mishra L K (Physics Dep, B.D. Evening College, Patna) : Evaluation of energy and effective mass of an electron in 2D system. Acta Cienc Indica-Phys 2003, 29(1), 65-72.

Using the standard technique of evaluation including exchanges and image potential term in the variational wavefunctions of the lowest subband, evaluated the energy levels of 2D-electron gas in the form of inversion layer of Si (100). The evaluation of (m*/m_op) versus N_s (total concentration of inversion layer) indicates that the value first decreases and then increases. But the values are always less than unity.

5 tables, 21 ref

002337   Verma M K (Physics Dep, Indian Institute of Technology, Kanpur-208 016) : Energy fluxes in helical magnetohydrodynamics and dynamo action. Pramana J Phys 2003, 61(4), 707-24.

Renormalized viscosity, renormalized resistivity, and various energy fluxes are calculated for helical magnetohydrodynamics using perturbative field theory. The calculation is of first-order in perturbation. Kinetic and magnetic helicities do not affect the renormalized parameters, but they induce an inverse cascade of magnetic energy. The sources for the large-scale magnetic field have been shown to be energy flux from large-scale velocity field to large-scale magnetic field arising due to non-helical interactions and inverse energy flux of magnetic energy caused by helical interactions. Based on our flux results, a primitive model for galactic dynamo has been constructed. The calculations yield dynamo time-scale for a typical galaxy to be of the order of 10⁸ years. The field-theoretic calculations also reveal that the flux of magnetic helicity is backward, consistent with the earlier observations based on absolute equilibrium theory.

1 table, 31 ref

002336   Upadhyay P N;Nandan S;Upadhyay S N (Physics Dep, Nalanda Mahila College, Biharsharif-803 101) : Study on the possible η ↑ π<. Acta Cienc Indica-Phys 2003, 29(1), 87-8.

Presents an account of result obtained by analysing the η → π⁺ π^- data. The η' (958 meson was produced in the π^-p → η'n interaction near its production threshold pion beam momentum. The absence of an enhancement for the η' meson in this decay mode is in agreement with its <60>2% upper limit on the branching ratio by others.

1 illus, 6 ref

002335   Upadhyay P N;Nandan S (Physics Dep, Nalanda Mahila College, Bihar Sharif-803 101) : Mass of the W boson. Acta Cienc Indica-Phys 2003, 29(2), 195-7.

A brief summary on the results of the measurements of the W boson has been presented. Its mass is determined to be (80.41±0.10) GeV at a full width or (2.06±0.06) GeV.

1 table, 23 ref

002334   Upadhyay P N;Nandan S (Physics Dep, Nalanda Mahila College, Biharsharif-803 101) : Production of the top quark (t). Acta Cienc Indica-Phys 2003, 29(2), 103-6.

A brief summary on the production of the top quark (t) has been presented. It is a well established quark.

1 illus, 1 table, 37 ref

002333   Tripathi G S (Physics dep, Berhampur University, Berhampur-760 007) : Magetism from lodestone to plastics. Indian J Phys-Pt A 2003, 77(6), 543-7.

Reviews the developments of the magnetic phenimena. Special importance is attached to recent advances in magnetic materials such as magnetic multilayers, half metallic magnets, coexistence of ferromangetism and superconductivity, spintronics and, last but not the least, photo induced magnetism in plastic materials.

1 illus, 43 ref