015167   Sivakumar K;Balaji S;Ganga Radhakrishnan (Chemistry Dep, Sri Chandrasekharendra Saraswathi Viswa Maha Vidyalaya (Deemed Univ), Enathur, Kanchipuram-631 561, Email: shivamk25@yahoo.co.in) : Insilico characterization of antifreeze proteins using computational tools and servers. J chem Sci 2007, 119(5), 571-4.

In the paper, seventeen different fish Antifreeze Proteins (Aprs) retrieved from Swiss-Prot database are analysed and characterized using in silico tools. Primary structure analysis shows that most of the AFPs are hydrophobic in nature due to the high content of non-polar residues. The presence of 11 cysteines in the rainbow smelt fish and sea raven fish AFPs infer that these proteins may form disulphide (SS) bonds, which are regarded as a positive factor for stability. The aliphatic index computed by Ex-Pasy's ProtParam infers that AFPs may be stable for a wide range of temperature. Secondary structure analysis shows that most of the fish AFPs have predominant α-helical structures and rest of the AFPs have mixed secondary structure. The very high coil structural content of rainbow smelt fish and sea raven fish AFPs are due to the rich content of more flexible glycine and hydrophobic proline amino acids. Proline has a special property of creating kinks in polypetide chains and disrupting ordered secondary structure. SOSUI server predicts one transmembrane region in winter flounder fish and atlantic cod and two transmembrane regions in yellowtail flounder fish AFP. The predicted transmembrane regions were visualized and analysed using helical wheel plots generated by EMBOSS pepwheel tool. The presence of disulphide (SS) bonds in the AFPs Q01758 and P05140 are predicted by CYS_REC tool and also identified from the three-dimensional structure using Rasmol tool. The disulphide bonds identified from the three-dimensional structure using the Rasmol tool might be correct as the evaluation parameters are within the acceptable limits for the modelled 3D structures.

4 illus, 9 tables, 37 ref

015166   Sivadhas A;Selvarajan P;Freeda T H (Physics Dep, Kamaraj College, Thoothukudi, Tamil Nadu, Email: pselvarajanphy@yahoo.co.in) : Studies on nucleation kinetics of triglycine sulpho-phosphate (TGSP) crystals added with magnesium sulphate. Bull pure appl Sci 2007, 26(2), 169-75.

Induction period measurements were carried out Cor pure and magnesium sulphate(MgSO₄)-added Triglycine Sulpho-Phosphate(TGSP) crystals at different supersaturation levels and various critical nucleation parameters such as Gibbs free energy change , interracial tension, the radius of critical nucleus and number of molecules in the critical nucleus were determined based on the classical theory for homogeneous nucleation. The relevant theory and the experimental results of nucleation kinetic studies are presented and discussed.

2 illus, 18 ref

015165   Singh W S;Singh N S;Ajay Soni;Singh S D;Singh L R;Okram G S (Phys Dep, Manipur Coll6pImphal-795 008, , Email: snath1@sancharnet.in) : Characterisation of ZnS nanocrystals prepared by wet chemical method. Indian J Phys 2007, 81(12), 1267-74.

ZnS nanocrystals of different sizes have been prepared by wet chemical method. X-Ray diffraction (XRD) pattern of ZnS powder shows the zinc blende structure of the crystals with a size variation from 2.9 to 1.6 nm with the addition of capping agent C₂H₅OSH. The optical absorption of ZnS deposited on quartz shows the blue shift with the increase in the bandgap from 3.6 to 4.0 eV. The observed low thermal activation energy of 0.4 eV determined from resistivity data on the pellets of capped ZnS suggests the formation of charge carrier traps in the presence of capping agent. Thermoluminescence (TL) glow curves of the nanostructured ZnS crystals could not be observed.

5 illus, 1 table, 26 ref

015164   Singh S P;Singh K;Roychoudhury M (Physics & Electronics Dep, Dr. R.M.L. Avadh Univ, Faizabad, U.P., Email: satya_pal22@yahoo.com) : Monte carlo simulation for diffusion limited surface directed phase separation. Proc Natn Acad Sci India-Sect A 2008, 78(Pt I), (NULL).

Surface directed phase separation with one phase B spin down (-1) preferred by the substrate has been studied using Glauber kinetics and spin exchange (Kawasaki exchange) model with semi-infinite free boundary condition. A computer simulation program has been developed for this purpose following metropolis algorithm and assuming conserved spin case with zero total magnetization. The temporal evolution of the patterns at k_BT≈ 0.6 eV below transition temperature T_c has been observed taking anti ferromagnetic interaction. Lattice size 200 x 100 has been taken with 50 : 50 concentrations of components A and B. The time evolution of patterns shows visible domain growth increasing with time. The phase separation takes place at first and then wetting process of phasc B dominates at later stages. Phase A spin up (+1) dcwcts partially or completely from the substrate and phase B wets the surface partially or completely vice-versa. As the system moves towards equilibrium, the diffusion process slows down asymptotically.

015163   Singh S P;Roychoudhury M (Physics and Electronics Dep, Dr. R. M. L. Avadh Univ, Faizabad, (U.P.)) : Evolution of patterns in an unstable thin polymer film adsorbed on solid substrate: a dynamic monte carlo study. Acta Cienc Indica-Phys 2008, 34(1), (NULL).

Results of Monte Carlo simulation performed for unstable thin linear polymer molecules adsorbed on solid substrates, are presented. Thin polymer films of thickness <60>100 nm show spinodal dewetting when annealed above their glass transition temperatures. A 24x18x6 size lattice has been initially taken. 24 beads have been taken along the backbone of the polymer chain in X direction. The initial average density of beads is 3.64. The film is placed between two hard boundaries in Z direction. A completely self avoiding random walk has been performed applying free boundary condition at the ends of chains. The attempted Monte Carlo update consists in a monomer displacement where the new position r' = r ± Δr with Δ r = (Δx, Δy, Δz) being chosen randomly and uniformly from the intervals -O.30 ≤ Δx, Δy, Δz ≤ 0.30. Glauber kinetic function has been used for shifting beads form their respective earlier positions. The evolution patterns show creation of holes in the film. Stacking of beads is also observed. Dominant spinodal waves are observed in the XV plane. The rate of initial equilibration process of free energy is also reported. A brief account of the theory of dewetting of thin film and dynamic Monte Carlo simulation procedure is given here.

015162   Singh R K;Sarma M;Mishra M K (Chem Dep, Indian Inst of Technol, Bombay, Powai-400 076, Email: mmishra@iitb.ac.in) : Approximate construction of local complex potentials for a time dependent wave packet based treatment of vibrational excitation cross-sections in resonant e-N₂, e-CO and e-H₂ scattering. Indian J Phys 2007, 81(10), 983-1002.

Approximation schemes based on the use of experimental data to fit a Morse potential as the target PE curve E_A(R) and chemically motivated parameterization schemes based on changes induced by electron-capture in the antibonding LUMO of the target (A) leading to lowering of bond order in the metastable anion (A^-) and thereby larger bond length, lower dissociation energy, and force constant for the resonant compound anion to construct a Morse PE curve E _A- (R) followed by the use of an exponentially decaying Γ_A- (R) which goes to zero at the crossing point between E_A (R) and E_A-(R) to construct the anionic width function Γ_A-(R) such that the local complex potential (LCP) for the resonant anion W_A-(R) is given by W_A-(R) = E_A-(R) -(i/2) Γ_A-(R) have been used to gain insight into the formation and decay of ²Π_g N^-₂, ²Π CO^- and ²∑⁺_u H^-₂ shape resonances. An analysis of the vibrational excitation cross-sections obtained from the use of these approximate LCPs in a time dependent wave packet scheme shows that the chemically motivated construction of the anionic LCP W_A- (R), can be quite effective.

9 illus, 1 table, 66 ref

015161   Singh J P;Johri U C;Prem Chand (Phys Dep, G.B. Pant Univ of Agric and Technol, Pantnagar-263 145, Email: jitendra_singh2029@rediffmail.com) : Study of Cu_xBa_1-x TiO₃ ceramic system. Indian J Phys 2007, 81(12), 1275-82.

Cu_xBa_1-xTiO₃ (x = 0.01, 0.05, 0.10) ceramic system was prepared by the conventional solid state reaction method. X-Ray diffraction analyses of this system indicate that all samples belong to the orthorhombic system. Cu addition results in non-linear variation of lattice parameters and expands the unit call of samples. The EPR spectra show trapping of copper as a free radical in the material. The relative dielectric constant of the samples increases with increasing copper concentration favoring the decrease in EPR signal intensity.

4 illus, 2 tables, 13 ref

015160   Singh A J;Karimi N A (Physics Dep, S.K. Women's College, Nambol (Manjipur)) : Effect of electric field stress and thermal aging on electrical conductivity of polyethylene terephthalate film. Bull pure appl Sci 2007, 26(2), 151-62.

Electrical conductivity of polyethylene terephthalate film of thickness 100 μm has been investigated under electric field stress upto I.5x10⁷ V/m and temperature varied from room temperature to 373K. From Ln J versus E^1/2 plots, the value of β_S and β_PF (Richardson-Schottky and Poole-Frenkel constants) were calculated and found that in unpolarized sample the Poole-Frenkel mechanism of conduction is operative but after the sample is polarized under the applied voltage of 1000V at 338K for one hour, the Poole-Frenkel mechanism of conduction changes to Richardson-Schottky mechanism of conduction, which shows that, the electrical conductivity of unpolarized sample was found greater than polarized sample. This was explained on the basis of Gross two charge theory.

5 illus, 2 tables, 14 ref

015159   Sharon M;Bhardwaj S;Jaybhaye S;Sathiyamoorthy D (Nanotechnology Research Lab, , Birla College, Email: sharon@iitb.ac.in) : Hydrogen adsorption by carbon nanomaterials from natural source. Asian J expl Sci 2008, 22(2), 75-8.

Utilization of some plant based fibers and some oil seeds to make carbon nanomaterial by pyrolysing them at very high temperature in an inert atmosphere, and characterize them by SEM for their morphology are reported. It was observed that carbon nanomaterials obtained from fibers based precursors like coconut fiber; baggas etc have fibrous structure whereas carbon Nano materials formed from seeds of different plants show very complicated porous carbon structures. These carbon materials are being utilized for the application of Hydrogen Storage. In order to compare the utilities of plant derived carbon nanomaterials, acetylene and alcohol have also been used to prepare carbon Nano materials by the pyrolysis. However, unlike plant based precursors. these precursors needed suitable catalysts, which adds to the cost The fibrous carbon from Bagasse (Saccharum officinarum) gave hydrogen adsorption of 0.656 wt% at 11 kg/m² pressure of hydrogen which is nearly the same as observed with carbon nanomaterials obtained from acetylene (0.51 wt%), suggesting that plant derived precursors can be used for such purpose. Efforts are made and presented in this paper to discuss the role of surface area and pore sizes in facilitating hydrogen adsorption.

8 illus, 8 tables, 21 ref

015158   Sharma S K (Physics Dep, Malaviya National Institute of Technology, Jaipur-302 017, Email: sksh@datainfosys.net) : Oxidation of Zr-based bulk amorphous and nanocrystalline alloys. Asian J expl Sci 2008, 22(2), 167-76.

Describes the current status of oxidation research in bulk amorphous alloys and their nanocrystalline forms obtained after annealing. Some novel results from the author's recent work carried out on oxidation of the bulk amorphous alloy Zr₆₅Cu_17.5Ni₁₀A_7.5 in air in its amorphous and the supercooled liquid states in the temperature range 573 K- 663 K using X-ray photoelectron spectroscopy (XPS) will also be presented.

5 illus, 23 ref

015157   Senthilkumar S;Perumal K;Srinivasan P S S (Basic Sciences Dep, Kongu Polytechnic Coll, Perundurai, Erode-638 052, Email: shansenthils@yahoo.com) : Performance analysis of a three dimensional compound parabolic concentrator. J Energy Heat Mass Transfer 2007, 29(3), 241-53.

For medium range temperature applications, focusing type collectors like Compound Parabolic Collector (CPC) are most commonly used Considerable research work has been carried out to improve the performance of the two dimensional compound parabolic concentrator (2-D CPC). The three dimensional compound parabolic concentrator (3-D CPC) was found to be more efficient than 2-D CPC because of the higher concentration ratio. In the present work a 3-D CPC was fabricated with a half acceptance angle of 4° for a spherical absorber of radius 100 mm. UV stabilized aluminized polyester foil having high reflectivity was pasted on the reflector for a total height of 441 mm and an aperture width of 540 mm. The optical efficiency was estimated theoretically and compared with the experimental value. Experimentally determined values of optical and thermal efficiencies were in good agreement with theoretically predicted value. The experimental results shown that the optical efficiency obtained from the 3-D CPC was significantly higher than that of the 2-D CPC of similar dimensions. Since the optical efficiency of the 3-D CPC was increased, the thermal efficiency of the collector was also increased In addition to that, an attempt was made to generate low pressure steam in the in situ steam generation mode, which was one of the possible applications of 3-D CPC module.

9 illus, 1 table, 14 ref

015156   Sekar R;Chakrabarty D (Physical, Research Lab, Ahmedabad-380 009) : Impact of space weather events on the coupling of ionospere and thermosphere over low latitudes. Asian J Phys 2007, 16(2-3), 247-72.

The effects of space weather events on the ionosphere-thermosphere system (ITS) over low latitudes have been studied over the decades and there exists considerable amount of work in the literature. However, the present communication reviews the results obtained in Physical Research Laboratory in last few years based on coordinated optical, radar and other ground-based measurements supplemented by satellite-borne measurements by others. Recently obtained evidences for the effects of interplanetary electric field (IEF), on OI 630.0 nm nightglow and on the development of Equatorial Spread-F (ESF), are discussed here. The influences of space weather events on 01 630.0 nm dayglow emission and on the temperature of thermosphere are indicated. The gravity wave modes associated with space weather events are also addressed.

13 illus, 103 ref

015155   Santra A K;Sen S;Chakraborty N (Power Engineering Dep, Jadavpur Univ, Salt Lake Campus, Block-LB, Plot-8, Sector-III Salt Lake, Kolkata-700 098, Email: aksantra@pe.jusl.ac.in) : Comparison of heat transfer augmentation in a square cavity using nanofluid following two different thermal conductivity models. J Energy Heat Mass Transfer 2007, 29(4), 289-310.

Effect of nanofluid (suspension of copper nanoparticles in water) has been studied as a cooling medium to simulate the heat transfer behavior in a differentially heated square cavity. The transport equations are solved numerically using finite volume approach using SIMPLER algorithm. It has been observed that the heat transfer augmentation is possible using nanofluid in comparison to conventional fluids. The thermal conductivity of nanofluid has been determined by Maxwell-Garnett (MG) model as well as by Bruggeman (BR) Model. The rate of heat transfer increases with the increase in solid volume fraction of the nanofluid. The results indicate that the heat transfer rate using Bruggeman Model is much higher than that of MG model.

13 illus, 1 table, 25 ref

015154   Ruhul Amin M;Rocco R (Mechanical and Industrial Engng Dep, Montana State Univ, 220 Roberts Hall, Bozeman Montana 59717, USA, Email: ramin@me.monatana.edu) : Modeling of a space auxiliary electric power system based on closed loop brayton cyles. J Energy Heat Mass Transfer 2007, 29(3), 191-208.

A closed loop Brayton cycle is modeied using Simulink^TM, an extension of MATLAB^TM. The Brayton cycle is used in conjunction with a direct gas cooled nuclear reactor to produce auxiliary electric power for space exploration applications. Efforts were focused in developing a dynamic model where information from the previously tested steady state model was used Individual component of the cycle that are modeled with user supplied input include: turbine, compressor, generator, heating recuperator, heat rejecting radiator, and ducting. Geometric characteristics, flow specifications and thermophysical properties were user supplied components in the model. A simplified model for the dynamic behavior of the reactor and shield components are being used. The accuracy of the model was verified by comparing the model's steady state results. A parametric study was conducted to demonstrate the functionality of the model. Results are obtained for a range of radiator lengths while other parameters are held constant. The performance of the model for different components was tested by using a low mass flow rate of 0.8112 kg/s and a high mass flow rate of 3.5 kg/s.

6 illus, 7 tables, 9 ref

015153   Riaz S S;Ray D S (Physical Chemistry Dep, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032, Email: pcdsr@mahendra.iacs.in) : Difusion and mobility driven instabilities in a reaction diffusion system. Indian J Phys 2007, 81(11), 1177-1204.

Interplay of reaction and diffusion in a chemical system may lead to many interesting selforganization phenomena like stationary pattern, waves, spirals and targets etc. in spatially extended nonlinear dynamical systems far from equilibrium. One may trace their origin to different instabilities. In this review we have presented a pedagogical exposition of two such instabilities relating to stationary pattern formation. The first one is the diffusion-driven instability, the Turing instability, arising from disparate diffusivities of two reacting components in a reaction-diffusion system under appropriate condition. The second one is the differential flow induced chemical instability which can be brought in by application of electric and magnetic fields. The analysis of instabilities and simulation of patterns have been carried out on chlorine dioxide-iodine-malonic acid reaction (CDlMA), which has served as an experimental testing ground for various theories in the last two decades.

12 illus, 87 ref

015152   Ravi Kumar N;Rama Krishna K;Sita Rama Raju A V (Mechanical Engineering Dep, Gudlavalleru Engng Coll, Gudlavalleru-521 356, Email: ravi_naradosu@yahoo.com) : Second law analysis of heat recovery steam generator (HRSG) in combined cycle power plant. J Energy Heat Mass Transfer 2007, 29(2), 119-36.

Combined cycle power plants play an important role in the present energy sector. The main challenge in designing a combined cycle power plant is proper utilization of gas turbine exhaust heat in the steam cycle in order to achieve optimum steam turbine output. Most of the combined cycle developers focused on the gas turbine output and neglected the role of the heat recovery steam generator (H RSG), which strongly affects the overall performance of the combined cycle power plant. The present paper is aimed at optimal utilization of the flue gas recovery heat with different HRSG configurations of single pressure (sp) and dual pressure (dp). The combined cycle efficiency with different HRSG configurations have been analysed parametrically by using first law and second law of thermodynamics. It is observed that in the dual cycle HP steam turbine pressure must be high and LP steam turbine pressure must be 1011' for better heat recovery from HRSG.

18 illus, 2 tables, 8 ref

015151   Rao U S;Srinivas G;Ajeeta N;Ojha P (Pysics Dep, S.S.N. Engineering College, Ongole-523 001) : Molecular ordering of a nematogen: 9CB-A statistical analysis based on quantum mechanics. Bull pure appl Sci 2007, 26(2), 89-101.

A computational analysis of ordering in 4-cyano-4'-nonylbiphenyl (9CB) has been carried out on the basis of quantum mechanics and intermolecular forces. The evaluation of atomic charges and dipole moment at each atomic centre has been carried out through an ail-valence electron (CNDO/2) method. The modified Rayleigh-Schrodinger perturbation theory along with multicentered-multipole expansion method has been employed to evaluate long-range intermolecular interactions while a '6-exp' potential function has been assumed for short-range interactions. The total interaction energy values obtained through these computations were used to calculate the probability of each configuration at room temperature (300K), phase transition temperature (320.5K.) and above transition temperature (450K) using the Maxwell-Boltzmann formula. A comparative picture of molecular parameters like total energy, binding energy and total dipole moment of 9CB with other nematogens 3CB (4-cyano-4'-propylbiphenyl), 5CB (4-cyano-4'-pentylbiphenyl) and 7CB (4-cyano-4'-heptylbiphenyl) has been given. A model has been developed to describe the nematogenicity of 9CB in terms of their relative order with the molecular parameter introduced in this article.

8 illus, 1 table, 20 ref

015150   Ramis M K;Jilani G (Mechanical Engng, National Institute of Technol, Calicut-673 601, Email: jilani@nitc.ac.in) : Heat transfer characteristics of a nuclear fuel element cooled in a surrounding medium. J Energy Heat Mass Transfer 2007, 29(4), 271-88.

This paper deals with the thermal design aspects of a rectangular nuclear fuel element dissipating fission heat in a surrounding medium. Considering average heat transfer coefficient over its surface, at first, the validity of one-dimensional model is examined next, various critical parameters, which govern the thermal design of the two-dimensional model are obtained While the solution of one-dimensional model is obtained analytically, second order finite difference schemes are employed to solve the equation governing the two-dimensional model. The results are presented for a wide range of aspect ratio, A_n Biot number Bi and heat generation parameter Q. It is concluded that for A_r ≥7.0, Bi and Q being kept fixed; one-dimensional model prediction is quite satisfactory. Further, it is concluded that there exist the critical values of the parameters above or below which the temperature of the fuel element crosses its allowable limit.

14 illus, 2 tables, 7 ref

015149   Pinaki Pal;Krishna Kumar (Kabi Sukanta Mahavidyalaya, , P.O. Angus, Dist - Hooghly-712 221, Email: kumar@phy.iitkgp.ernet.in) : Effect of magnetic field on wavy roll instability. Indian J Phys 2007, 81(11), 1215-26.

A low-dimensional model to study the effect of uniform horizontal magnetic field on wavy instability. The model is derived for the thermal convection in very small Prandtl-number-fluid, that shows direct transition from stationary two-dimensional rolls to three-dimensional waves at the onset of secondary instability. The flow kinetic energy shows both random bursting with power-law histogram as well as periodic behavior depending on the wavenumber q of the wavy perturbations. The uniform magnetic field applied along the roll axis suppresses the random bursting and leads to time-periodic waves for very low but finite Prandtl-number-fluids. The secondary instability appears in the form of periodic waves for wavy perturbations with smaller wavenumbers. The magnetic field suppresses the periodic waves leading to stationary two-dimensional rolls. Lowering of Prandtl number requires higher values of the magnetic field for the same effect. The results of the model compare well with those obtained from the model for zero-Prandtl-number convection.

9 illus, 15 ref

015148   Pathak A K;Mukherjee T;Maity D K (Radiation and Photochem Div, Chem Group, Bhabha Atomic Research Cente, , Mumbai-400 085) : Structure, energy and IR spectra of K-nNH₃ cluster : a theoretical study. Indian J Phys 2007, 81(9), 901-13.

We report microscopic structure and properties of small size clusters of ammonia and K atom of the type K-nNH₃ (n ≤ 6). Structure of different minimum energy configurations for each size cluster has been predicted following Newton-Raphson procedure with a variety of initial guess structures. A density functional having 50% HF exchange and 50% Slater exchange with additional correlation effects from LYP functional, namely, BHHL YP has been applied with Gaussian triple split valence basis set (6-311 G) with polarization (2d,2p) and diffusion function on each atom for all the calculations. It is observed that N of NH₃ is oriented towards K atom of each cluster. In all the structures, K atom remains as mono positive ion and the ejected electron is delocalized over the whole cluster. IR spectra are calculated based on Hessian calculations on the optimized structures. A large shift (Δ v = + 100 cm^-1) of IR band corresponding to the inversion of ammonia is predicted in all the clusters. On interaction with K atom, N-H stretching band of NH₃ becomes much stronger than the inversion band. As a nymber of stable minimum energy structures are predicted for higher clusters, weighted average IR spectra is generated based on statistical population of stable minimum energy structures at 150 K. Weighted average solvation energy and vertical ionization potential (VIP) of the solvated clusters are also presented. Calculations are carried out to find out a few low lying excited states for all the clusters, K(NH₃)_n (n =1-6) at the CIS/6-311++G(2d,2p) level. Visualization of appropriate MOs suggests that the strong optical absorption is mostly due to HOMO → LUMO electronic transition. The optical absorption profiles of a few selected K(NH₃)n clusters are also reported.

5 illus, 1 table, 37 ref

015147   Pal S;Nayana Vaval;Sajeev Y (National Chem Lab, Phys Chem Div, , Pune-411 008) : Shape resonance in electron molecule scattering using coupled cluster method. Indian J Phys 2007, 81(10), 1061-7.

The Fock space multi-reference coupled-cluster (FSMRCC) method along with the complex absorbing potential (CAP) is used for the study of the shape resonance energy and width in an electron molecule collision. We study the shape resonances in e^- -H₂CO and e^- -CO.

2 tables, 29 ref

015146   Pal S;Goswami B;Pranab Sarkar (Chem Dep, Visva-Bharati Univ, Santiniketan-731 235, Email: pranab_69@yahoo.co.in) : Electronic structure of ZnS nanotube : a density-functional study. Indian J Phys 2007, 81(10), 1079-93.

Results of the theoretical calculations on structural, electronic and optical properties of ZnS nanotube. The calculations are performed by using density-functional tight-binding (DFTB) method. We have considered both single-walled and double-walled nanotubes and studied the variation of radial distribution, Mulliken population, density of states and band gap as functions of both tube radius and tube helicity.

10 illus, 33 ref

015145   Oztop H F (Mechanical Engng Dep, Firat Univ, TR-23119 Elazig/Turkey, Email: hfoztopl@yahoo.com) : Natural convection in tilted porous enclosures with discrete heat sources. J Energy Heat Mass Transfer 2007, 29(2), 83-94.

A porous cavity with discrete heating from two sides and cooled from ceiling is analyzed numerically, for different inclination angle. Finite volume method is used to solve the natural convection equation and the code is written using Simple algorithm. Solution of algebraic equations is made by TDMA (Three Diagonal Matrix Algorithm). The effects of some parameters such as Grash of number, Darcy number, inclination angle and porosity are investigated. It is observed that mean Nusselt number is increased with the increasing of inclination angle.

6 illus, 1 table, 24 ref

015144   Mitra U K;Ghosh N;Ghosh P;Acharyya S (Physics Dep, Sudarshanpur D.P.U. Vidyachakra, P.O. Raiganj-733 134, Email: uttam_mitra@rediffmail.com) : Studies on physico-chemical properties with the relaxation phenomena of some normal aliphatic alcohols in non polar solvent under Giga Hertz electric field at a single temperature. J Indian Chem Soc 2007, 84(3), 241-9.

Double relaxations of some normal aliphatic alcohols have been studied to get relaxation times T1 and T2 due to rotation of flexible part and end over end rotation of the whole molecule from the intercept and slope of a linear equation of (χ_0ij - χ^′_ij)/χ^<130>_ij against χ^″_ij/χ^<130>_ij for different weight fractions W_j's of solute in n-heptane at 25 °C under electric field frequencies of 24.33, 9.25 and 3.00 GHz. Alcohols like 1-butanol, 1-hexanol, 1-heptanol and 1-dccanol are long straight chain hydrogen bonded polymer type molecules having -OH groups which may bend twist or rotate internally about C-C bond under GHz electric field exhibiting characteristic T. Estimated T_J obtained from ratio of slopes of individual variation of χ^″_ij and χ^′_ij against W_j at W_j

015143   Misra A;Pandey D K (AMD Atomic Energy Dep, , W.R., Jaipur-302 033) : Microfacies and depositional environment of the bathonian Jhurio formation at the jumara dome, Kachchh, western India. Asian J expl Sci 2008, 22(2), 123-40.

Jumara Dome was taken up for the present study. In accordance with the above-mentioned objectives detailed stratigraphical sections of the Jhurio Formation have been measured. Macrofacies were recorded for corroborating the microfacies data. Microfacies analysis has been carried out by studying thin-sections of rock samples under the microscope with the aim to interpret the depositional environment and setting. The study helped in the reconstruction of the depositional environment and setting at the Bathonian times represented by the Jhurio Fm. The Jhurio Fm. at the Jumara dome is characterized by well-bedded limestone-marl/marlstone alternations and massive limestones (packstones and grainstones). The sections have several units where the limestone show nodular feature. Various microfacies types are present in the Jhurio Fm. at the Jumara dome. The MF types are associated into two MF associations at the dome. A carbonate ramp setting seems to have been prevalent at the time of sedimentation of the carbonates during the Bathonian. In general, the depositional environment seems to have been a marine, open sea, mid to outer (deep) ramp environment. Depositional environment was largely low energy just below storm wave base which had seen phases of slight influence of storm-events. Reworked sediments of the transgressive phase witnessed relatively higher energy depositional environment.

2 illus, 2 tables, 40 ref

015142   Misra A;Datta S N (Chem Dep, North Bengal Univ, Siliguri, Darjeeling-734 430) : Relativistic hamiltonian for neutral atom of spin-1/2 nucleus in homogeneous magnetic field. Indian J Phys 2007, 81(9), 881-8.

A relativistic formalism to construct the Hamiltonian for a general N-electron neutral atom with a spin-1/2 nucleus and placed in a homogeneous magnetic field is discussed here. Projected Coulomb and Breit interactions are taken to describe the inter-particle interaction through second order in fine structure constant. The center of mass motion is separated from the movement of the neutral (N+ 1) -fermion system. Using a series of suitable unitary transformations, the Hamiltonian can be brought into a separable form. The correct atomic Hamiltonian in the non-relativistic limit is also discussed. The treatment can be extended to the case of a molecule containing atoms of only spin-1/2 nuclei.

12 ref

015141   Mehta N;Datta S N (Chem Dep, Indian Inst of Technol Dep, Bombay, Powai, Mumbai-400 076, Email: sndatta@chem.iitb.ac.in ) : Computational strategies for redox processes in condensed phase : both explicit and implicit solvation treatments. Indian J Phys 2007, 81(9), 851-69.

Detailed account of the theory of solvation models, especially those involved in the calculation of the reduction potentials of biomolecules in a solvent or a membrane has been provided. The explicit solvation model involves a hybrid quantum mechanical-molecular mechanical (QM/MM) treatment of the solvated biomolecule and a dynamical treatment of the primary solvent layer through either Molecular dynamics (MD) or Monte-Carlo (MC) simulations. Contributions of the solvent molecules in the bulk to the free energy change of the reduction process is incorporated in the form of the Born free energy of ion-dielectric interaction, the Onsager energy of dipoleªdielectric interaction and the Debye-Huckel energy of ion-ionic cloud interaction. The implicit solvation treatment employs the dielectric polarisable continuum model (DPCM) where all the solvent molecules together are represented as a continuum with a fixed dielectric constant. Whereas the implicit model only accounts for an average molecule-medium interaction, the explicit model also considers fluctuations of the medium molecules from their average coordinates in thermal equilibrium. The theory and the models are exemplified by calculations on three biomolecules in different environments. The QM/MM method could successfully reproduce the standard reduction potential of plastocyanin in water. The QM/MM/MD + Born/Dnsager/Oebye-Huckel procedure was used to obtain the standard oxidation and reduction potentials of Chlorophyll-a in acetonitrile. The QM/MM/MC + Born/Onsager/Oebye-Huckel technology was adopted to determine the one- and two-electron reduction potentials of Pheophytin-a in DMF.

4 illus, 4 tables, 34 ref

015140   Mandal J;Gatak B (Physics Dep, T M Bhagalpur Univ, Bhagalpur-812 007) : Evaluation of van der waals dipole-dipole and diple-quadrupole energies and crystal energies in copper, silver and thallium halides. J Indian Chem Soc 2007, 84(2), 145-8.

The Slater-Kirkwood variational method is applied to estimate the Van der Waals dipole-dipole (vdw) and dipole-quadrupole co-efficients for ion-pair interaction in copper, silver and thallium halide crystals. In the analysis of crystal binding based on the interionic force model, the contributions arising from the vdw dipole-dipole and dipole-quadrupole interactions and the short-range repulsive interactions of the type of Born-Mayer, Hellmann and Ali-Hasan have been taken into account. The calculated values of the crystal energy using the Ali-Hasan repulsive potential agree closely with the experimental value.

3 tables, 14 ref,

015139   Mallikarjuna Reddy P;Rajagopal K;Govinda Rajulu K (Mechanical Engng Dep, G. Pulla Redy Engng Coll, Kurnool 518 002, Email: pmareddy@sancharnet.in) : Simulation of heat transfer in S.I. engine combustion chambers. J Energy Heat Mass Transfer 2007, 29(1), 1-11.

Multi-Dimensional simulation of heat transfer in 4 - Valve S.I. engine combustion chambers was carried out using Fluent CFD software. In the present work three different types of combustion 'chambers were studied. The predictions are based on two different approaches, one of which based on the assumption of local equilibrium non-accelerating boundary layers (Standard wall function model) and another, which take into account non-equilibrium effects of turbulent boundary layers as well as transient core pressure changes as they occur in the combustion chamber of reciprocating engines (Transient Heat Transfer model). The temperature boundary conditions on the walls and the flow boundary conditions at the inlet and outlet ports were extracted from experimental data, which satisfied the engine volumetric efficiency. In order to simulate the combustion process, the Zimont premixed combustion model was employed. The results of the present study show the time variation of surface heat transfer coefficient on the face of the piston and the cylinder head.

7 illus, 17 ref

015138   Mainak Sadhukhan;Deb B M (S N Bose National Centre for Basic Sci, , JD Block, Sector III, Salt Lake, Kolkata-700 098) : Aspects of electron dynamics in a helium atom under an intense laser field. Indian J Phys 2007, 81(10), 969-81.

Aspects of the dynamics of electrons in a helium atom interacting with an intense laser of intensity 1 x 10¹⁵ W cm^-2 over a time of 100 fs are theoretically studied through a single time-dependent generalized nonlinear Schrodinger equation (GNLSE) of motion. The GNLSE was derived earlier by combining time-dependent (TD) density functional theory and quantum fluid dynamics. It has been solved fully numerically to yield results on the TD number of electrons, electron density changes, oscillating induced dipole moment, etc. The method can reveal attosecond changes in the electron density as well as create an attosecond laser pulse, of peak intensity -10⁹ W cm^-2, out of the generated high-order harmonics. The method goes beyond the linear-response formalisms and, in principle, calculates density to all orders of change.

7 illus, 22 ref

015137   Madhukar K;Poticelli G (Physics Dep, Nizam College (Autonomous), Osmania Univ, Hyderabad) : Study on hyperfine line width mechanism in solution EPR spectra of [Cu (den)L]X₂mH₂O complexes. Bull pure appl Sci 2007, 26(2), 119-23.

Hyperfine line width calculations of EPR spectra of Cu(II) in solutions of pyridine DMF were carried out in the complexes of [Cu(den)L]X₂.mH₂O where L = tn or en, X = Br or Cl, m = 0 or 1 Hyperfine line widths were evaluated using Wilson and Kivelson's line width theory' which consider the effect of motional modulation of anisotropic g & A tensors. True line widths were obtained using computer simulations. Using the experimental AHpp values for different m values, as obtained from the computer simulation spectra, the values of (α + α'), β, γ and δ were evaluated, where a' represents the residual line width. A difference between isotropic spin rotational relaxation and residual line is noticed in DMF & pyridine solutions of [Cu(den)tn]Br₂ and pyridine solution of [Cu(den)tn]Cl₂H₂O than the other cases. This may be attributed to the effect of dissolved oxygen.

1 illus, 1 table, 14 refxs

015136   Lo C Y (Applied and Pure Research Institute 17-Newcastle Drive, Nashua, NH 03060, USA) : Einstein principle of equivalence and the Einstein-Minkowski condition. Bull pure appl Sci 2007, 26(2), 73-88.

Einstein insisted on the fundamental importance of his equivalence principle. However, many pay only lip-service to this view because: 1) his principle had not been rigorously defined. 2) many confused Einstein's equivalence principle of 1921 with Einstein's 1911 preliminary application of equivalence between acceleration and Newtonian gravity, 3) the Einstein-Minkowski condition has not been illustrated with a verified example, 4) the crucial role of Einstein's equivalence principle in predictions was not recognized, 5) compatibility of a uniformly accelerated frame and relativity is only a faith, and 6) efforts to obtain the space-time metric of a uniform gravity had failed. Such confusion and misunderstanding of Einstein's equivalence principle were the causes of theoretical errors and accepting unphysical solutions as valid in physics. These issues are addressed and the metric for a uniform gravity is proven to be time-dependent. Thus, Einstein's equivalence principle is rigorously defined and illustrated. Moreover, Einstein's equivalence principle implies invalidity of the so-called "covariance principle.

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015135   Lakhina G S (NO, Indian Inst of Geomasgnetism, New Panvel (W), Navi Mumbai-410 218, Email: lakhina@iigs.iigm.res.in) : Mechanism for generation of ultra low-frequency waves in the polar cusp region. Asian J expl Sci 2008, 22(2), 95-101.

Ultra low-frequency (ULF) electromagnetic waves, in the frequency range of <126> 1 mHz to 3 Hz, have been observed in the polar cusp and other regions of the Earth's magnetosphere by several spacecrafts, e.g., Geotail, Polar and CLUSTER. There are strong indications that these waves are generated locally by the energetic ion beams injected during magnetic reconnection taking place at the magnetopause. Ion beams observed in the polar cusp, plasma sheet boundary layer (PSBL), and on the auroral zone field lines are expected to have spatial gradients in their drift velocity. A generation mechanism for the ULF waves is proposed in terms of kinetic Alfven wave instability driven by velocity shear of the ion beams. The noise due to velocity shear driven Alfven modes is electromagnetic in nature, and also has a finite parallel electric field component.

4 illus, 20 ref

015134   Kumar D;Kumar N (Physics Dep, B.N.M.V. College, Sahugarh, Madhepura (Bihar)) : On integrability criteria of hamiltonian structure in relativity. Bull pure appl Sci 2007, 26(2), 177-80.

The main purpose here is to investigate and extend the integrability condition for Half-fall solution to Einstein's equation. The H-space techniques of Neuman and Twistor constructions adopted by Penrose and Rindler (1984) have been found in adequate in view of its on-local-character in space-time which obstruct its Hamiltonian Formulation. Analyzes the results derived by Penrose on Tetrad formalisation with its application on space time geometry.

7 ref

015133   Kumar A (Physics Dep, M.L.S.M. College, Darbhanga-846 004) : Study of metal coated dielectric conical horn. Bull pure appl Sci 2007, 26(2), 163-7.

A conical dielectric waveguide whose outer surface is metallized and whose inner surface is coated with circumferentially oriented conducting strips with a periodic variation along the horn is presented. It may be designed to have minimal cross polarization at two arbitrary refracted frequencies, as for a dual depth corrugated horn. Compared to a corrugated horn, it has the potential of lower weight and lower price. Small horns will have some cross polarization due to undesired radiation from the fields transmitted within dielectric.

4 illus, 7 ref

015132   Krishna Kumar;Paul Supriyo;Jain D (Phys and Meteorol Dep, Indian Inst of Technol, Kharagpur-721 302, Email: Kumar@phy.iitkgp.ernet.in) : Rhombic patterns near a bicritical point in periodically forced surface waves. Indian J Phys 2007, 81(11), 1205-14.

Selection of rhombic patterns close to a bicritical point at the onset of primary surface instability in viscous fluids under two-frequency vertical vibration. Rhombic patterns appear to be natural at the primary instability in the form of a bicritical point, if the ratio of deriving frequencies is selected properly. Two different patterns which may be accessible in a Faraday experiment.

4 illus, 18 ref

015131   Krishna C B;Dhall R;Chopra S;Banerjee S (Electronics and Instrumentation Engineering Dep, Birla Institute of Technology and Science, Pilani-333 031) : Futuristic memory device: a theoretical modeling. Indian J Phys 2007, 81(12), 1315-22.

A theoretical modeling of a memory device that may be treated as an alternative to conventional flash memory devices based on the principle that proximity induces electric field modulation leading to a high ON-OFF current ratio, which can be used to distinguish between the two binary states 0 and 1. The present device is expected to operate with synthetic bilayer membrane opening up the possibility of a biocompatible memory device for the future. A first order calculation of parameters, relevant fabrication steps and challenges in commercialization of this device are also presented. The device has an edge over other flash and quantum-dot memories with respect to non-volatility and endurance.

6 illus, 17 ref

015130   Kazim A (Dubai Technol and Media Free Zone Authority, , Dubai Knowledge Village, P.O. Bax 73000 Dubai United Arab Emirates, Email: akazim@tecom.ae) : Assessment of film condensation on the external surfaces of a PEM fuel cell stack. J Energy Heat Mass Transfer 2007, 29(1), 43-59.

Assessment of heat transfer by film condensation of liquid water in a proton exchange membrane (PEM) fuel cell stack was carried out through coupling of heat and water condensation equations with the electrochemical equations in the fuel cell at various surface temperatures, operating pressures, surface lengths, stoichiometric ratios and cell voltages. The results demonstrate that the flow regime of water condensation in the fuel cell takes a laminar wavy profile with Reynolds number in the range of 30<60>Re<60>1,800. Moreover, similar profiles of heat and water condensation, mass flow rates of hydrogen and oxygen and inlet and exit air as well as heat generation are predicted. The magnitudes of these parameters illustrated to be inversely and directly proportional to the stack's surface temperature and operating pressure, respectively. However, temperature difference tends to be more influential than pressure difference.

10 illus, 1 table, 15 ref

015129   Kalanov T Z (Home of Physical Pronlems, Pisatelskaya 6a, 700200 Tashkent, Uzbekisten, Email: tzk_uz@yahoo.com) : Correct theoretical analysis of the foundations of classical thermodynamics. Bull pure appl Sci 2007, 26(2), 109-18.

The correct theoretical analysis of the generally accepted foundations of classical thermodynamics is proposed The principle of the unity of formal logic and rational dialectics is a methodological basis of the analysis The result is as follows: the foundations of classical thermodynamics (i.e., the first and second laws, equation of state, concepts of internal energy, of heat energy, of entropy, of temperature) contain logical errors The existence of logical errors is irrefutable proof of incorrectness of thermodynamics. The correct statistical foundations are proposed.

12 ref

015128   Jha B K;Kumar A (Physics Dep, L.N. Mithila Univ, Darbhanga (Bihar)) : Analysis of transient scattering from circular disc on geometrical theory of diffraction. Bull pure appl Sci 2007, 26(2), 126-9.

Study of transient scattering analysis has been made on geometrical theory of diffraction. Here the backscattered fields of perfectly conducting circular disc are analyzed from a transient signature viewpoint. This significant dominant scattering mechanisms are identified for both principal polarizations at a variety of angles. Particular attention is given to the edge wave Such type of study shall be very useful in this field of Radar Technology for rural communication purposes.

3 illus, 1 table, 7 ref

015127   Jha A (P.G. Department of PHysics, C.M. Science College, Darbhanga-846 004) : Far field to near field transformation on computational technique. Bull pure appl Sci 2007, 26(2), 137-42.

A far field to near field transformation based on computational fast multipole technique is presented In this approach multipoie expansion of the Green's Kernel is considered to evaluate the field in the vicinity of the antenna from the knowledge of the far field radiation pattern in several directions. As the far field measurements are given for a fixed number of directions by the data sample, an interpolation process of the far field is introduced The near field is computed at each point of the satellite surface. The numerical example validates the present approach in comparison to the physical optics approach.

1 illus, 8 ref

015126   Jee M;Singh A K;Singh M K;Singh G;Sharma A (University Department of Physics, B.R.A.S.U., Muzaffarpur, Bihar) : Electronic energy bands, density of states and charge transfer of gallium nitride. Bull pure appl Sci 2007, 26(2), 181-5.

Authors have calculated electronic bands, density of states and charge transfer and related physical properties for gallium nitride with the use of linear combination of atomic orbital formalism. This calculation also carrying out selfconsistent calculations for GaN using a minimal basis set. Initial charge density for α-GaN was calculated using the atomic orbital of Ga and N The variational method of Rayleigh-Ritz were used The calculated energy conduction bands, band gaps and effective masses of carriers agreed well with experimentally observed values. The minimum band gap of GaN for low temperature is 3.2 eV.

8 ref

015125   Jayachander Rao B;Mahapatra S (School of Chem, Univ of Hyderabad, Hyderabad-500 046, Email: smsc@uohyd.ernet.in) : On the electronic nonadiabatic effects in the H + H₂ reaction dynamics. Indian J Phys 2007, 81(10), 1003-21.

The effects of electronic nonadiabatic coupling on the dynamics of the most fundamental H + H₂ reaction are studied in this paper. A time-dependent wave packet approach along with the double many body expansion potential energy surfaces of the system is employed in the present investigation. The effect of reagent rotations and vibrations on the reactivity is mainly studied in the paper employing the coupled states approximation. Initial state-selected and energy resolved reaction probabilities have been reported for reagent, H₂ in its (v = 0, j = 0-10) and (v = 0-10, j = 0) states, respectively, upto the three-body dissociation energy of H₃ (<126>4.7 eV). Calculations are performed both with and without surface coupling and the results are compared. Integral reaction cross sections have been calculated from the reaction probabilities. All partial wave contributions upto the total angular momentum, J = 50 are included to obtain converged integral reaction cross sections. Analysis of the reaction probability and reaction cross section data shows that the nonadiabatic effects are insignificant at small values of j and v, which become more pronounced with an increase of the latter quantities. Electronic nonadiabatic effects appear to be more important in the reaction dynamics of rotationally excited H₂.

7 illus, 58 ref

015124   Jangid R A (Microwave Res Lab, Phys Dep, Raj Rishi Govt. P.G. Coll, Alwar-301 001, Rajasthan, Email: rajangid@yahoo.co.in) : Dielectric dispersion and relaxation studies of some pure nicotinates and their ternary mixtures at a single microwave frequency and temperature 36.5°. Indian J Phys 2007, 81(12), 1283-94.

Experimental values of dielectric parameters like ε_s' ε_λ, ε', ε", τ_(O)' τ₍₁₎' τ₍₂₎' μ_D(S), μ₀(S), μ_D (microwaves) and ∝ for four pure nicotinates namely benzyl nicotinate (BN), ethyl isonicotinate (EIN), methyl isonicotinate (MIN) and ethyl nicotinate (EN) and their ternary mixture compositions of the ternary systems (BN+MIN+EN) and (BN+EIN+EN) have been determined at a single microwave frequency 10.17 GHz and temperature 36.5°C. The compounds under investigation have been used in pure liquid from as dielectric samples. The most probable relaxation time τ(0) is determined using Frohlich's equation. The experimental values of τ(0) for ten ternary mixture compositions are compared with those calculated by different theoretical relations.

3 tables, 12 ref

015123   Jain N C;Gupta P (Mathematics Dep, Unit of Rajasthan, Jaipur-302 004, Email: jainnc181@rediffmail.com) : Unsteady magnetopolar free convection flow in slip flow regime with variable permeability and constant heat flux. J Energy Heat Mass Transfer 2007, 29(3), 227-40.

Examines the problem of unsteady free convection flow with heat source/ sink of an electrically conducting viscous incompressible polar fluid through a porous medium with variable permeability in slip flow regime over an infinite vertical plate. Permeability of the porous medium and suction on the plate decrease exponentially with time. Using perturbation technique the expressions are obtained for velocity and temperature distributions, skin friction and Nusselt number. Effects of rotational viscosity parameter a, and couple stress parameter β₁, and other parameters entering into the problem are calculated numerically and are shown graphically on the expressions obtained in the problem. It is being found that the skin friction increases with the increase in αj, but decreases with the increase of β₁. It is also observed that for both the basicfluids water (P = 7.0) and air (P = 0.71) Nusselt number increases with the increase of heat source parameter.

6 illus, 14 ref

015122   Jain C;Dutta A;Paul B (Phys and Astrophys Dep, Univ of Delhi, Delhi-110 007, Email: chetanajai8n11@yahoo.co.in) : Orbital evolution measurement of the accreting millisecond X-ray pulsar SAX J1808.4-3658. J Astrophys Astr 2007, 28(4), 197-206.

Presents results from a pulse timing analysis of the accretion-powered millisecond X-ray pulsar SAX 11808.4-3658 using X-ray data obtained during four outbursts of this source. Extensive observations were made with the proportional counter array of the Rossi X-ray Timing Explorer (RXTE) during the four outbursts that occurred in 1998, 2000, 2002 and 2005. Instead of measuring the arrival times of individual pulses or the pulse arrival time delay measurement that is commonly used to determine the orbital parameters of binary pulsars, we have determined the orbital ephemeris during each observation by optimizing the pulse detection against a range of trial ephemeris values. The source exhibits a significant pulse shape variability during the outbursts. The technique used does not depend on the pulse profile evolution, and is therefore, different from the standard pulse timing analysis. Using 27 measurements of orbital ephemerides during the four outbursts spread over more than 7 years and more than 31,000 binary orbits, we have derived an accuªrate value of the orbital period of 7249.156862(5) s (MJD = 50915) and detected an orbital period derivative of (3.14 ± 0.21) x 10^-12 s S^-I. Included a table of the 27 mid-eclipse time measurements of this source that will be valuable for further studies of the orbital evolution of the source, especially with ASTROSAT. It was pointed point out that the measured rate of orbital period evolution is considerably faster than the most commonly discussed mechanisms of orbital period evolution like mass transfer, mass loss from the companion star and gravitational wave radiation. The present time scale of orbital period change, 73 Myr is therefore likely to be a transient high value of period evolution and similar measurements during subsequent outbursts of SAX J1808.4-3658 will help us to resolve this.

3 illus, 3 tables, 27 ref

015121   Goud B V S (USIC Dep, Acharya Nagarjuna Univ, Nagarjuna Nagar-522 510, Email: goudbvs@yahoo.com) : Interface of impedance analyser to computer: phase transition studies through dielectrics in ferroelectric liquid crystal. Bull pure appl Sci 2007, 26(2), 143-50.

An automated experimental set-up for measurement of dielectric and other electrical parameters in thermotropic liquid crystals under the application of varying frequency and bias voltage of the applied a.c. field as a function of temperature has been designed and fabricated The key components, viz.. Impedance Analyser and Temperature Controller are independently controlled by two computers. The Impedance Analyser is interfaced to computer through GPIB using custom built hardware and controlled using indigenously developed GWBASIC based software to record the data in the computer for further processing with the help of a computer. Using the present set-up phase transition studies has been carried out in a newly synthesized Schiff base compound, 4-(2-chloro-propionyloxy)benzylidene -4'-amino-2methylbutylcinnamate(CPOBAMBC).

1 illus, 1 table, 13 ref

015120   George F;Dhilip Kumar T J;Sanjay Kumar (Chem Dep, Indian Inst of Technol, Madras, Chennai-600 036, Email: sanjay@iitm.ac.in) : Scattering resonances in low-energy H<. Indian J Phys 2007, 81(9), 889-900.

A time-dependent nuclear wave packet methodology has been undertaken in three dimensions for total angular momentum (J = 0) to study the scattering resonances (quasibound states) in H⁺ + CO collisions at low energies using an accurate ab initio potential energy surface of the ground electronic state of the system obtained through multi-reference configuration interaction calculations. The existence of large number of scattering resonances indicates the importance of indirect scattering at low collision energies.

6 illus, 2 tables, 26 ref

015119   Gavai R V (Theoretical Physics Dep, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400 005, Email: gavai@tifr.res.in) : Re-creating the big bang. Asian J expl Sci 2008, 22(2), 117-21.

Few microseconds after the Big Bang, universe may have been dominated by the quark-gluon plasma (QGP), an hitherto undiscovered phase predicted by the current theory of strong interactions. Heavy ion' collision experiments at very high energies at Brookhaven National Laboratory, New York and the upcoming Large Hadron Collider in CERN, Geneva have the potential for producing the right conditions for such a phase transition to occur. This introductory review of the subject endeavours to explain what quark-gluon plasma is, why it is important and how it can be created and studied in laboratory.

015118   Ganeshpure P A (Research Centre, Reliance Industries Ltd Vadodara Manufacturing Div, , Vadodara-391 346, Email: Pralhad. Ganeshpure@ril.com) : Ionic liquids : environment-friendly solvents and catalysts for the future. Asian J expl Sci 2008, 22(2), 113-15.

Ionic liquids are receiving much attention as environment-friendly mediums for the organic reactions. Improvements in the rates of reaction and selectivity have been realized in many cases when ionic liquids were used in the places of the conventional solvents. Their application to esterification reaction resulted in high yields without removal of the water formed in the reaction. The esters form separate liquid phase in the reaction which are separated easily by decantation. It was demonstrated that high melting points of the ammonium salts did not prevent their use as ionic liquids in the esterification reaction.

5 ref