004269   Kshrotriya A;Jain S K (Phys Dep, SML(PG) College, Jhunjhunu, Rajasthan) : Measurement of heat storage coeficient of solid-solid-air mixtures at different pressures. Indian J pure appl Phys 2003, 41(9), 700-3.

Using a plane heat source technique, the heat storage coefficient (HSC) of some varieties of selected three phase systems (solid-solid-air mixture) like, loose cement dispersed with marble powder, aluminium powder and iron powder respectively, has been measured at varying interstitial air pressures. The behaviour of the HSC values with the variation of pressure between the range 0.1 to 760 mm of mercury has been discussed. There is a marked change in the values of HSC for increase or decrease in the pressure region from 0.1 to 760 mm of mercry.

5 illus, 2 tables, 10 ref

004268   Khandpekar M M (Phys Dep, Birla College, Kalyan-421 304) : Thermal evaporation of diglycine hydrogen fluoride crystals. Indian J pure appl Phys 2003, 41(9), 704-6.

Diglycine hydrogen fluoride crystals have been grown from aqueous solution by slow evaporation technique, at room temperature. Thermal evaporation at the surface of the crystal shows formation of boat-shaped pits, in accordance with the (100) symmetry of cleavage face, with density of pits concentrated in some regions. The sizes of the pits increase at the same sites on prolonged thermal etching and show correspondence of few pits on matched courterparts. The rare evidence of mismatch of new domains is detected. The presence of typic circular feature, pits formed on domains, thick and thin domain lines and the glide band due to thermal stresses are illustrated.

7 illus, 10 ref

004267   Kannappan V;Xavier Jesu Raja S;Jaya Santhi R (Postgraduate and Research Chemistry Dep, Presidency College, Chennai-600 005) : Ultrasonic studies on molecular interaction of certain carbonyl compounds in n-hexane and chloroform solutions. Indian J pure appl Phys 2003, 41(9), 690-5.

The ukltrasonic velocities (U), densities (ρ), and viscosities (ρ) are measured in n-hexane and chloroform solutions of acetophenone, ethyl methyl ketone and benzaldehyde at 298 K, in the concentration range 0.05-1 M. The variation in ultrasonic velocity values indicate solute-solvent interactions in both the media and stronger interactions are observed in chloroform solutions. Acoustical parameters such as adiabatic compressibility (β), linear free length (L_t), relaxation time (τ), absorption coefficient (α/ƒ²), molecular interaction parameter (χ), and solvation number (S_n) values are also calculated. These values indicate that, the carbonyl compounds are strongly attracted by chloroform molecules probably through inter molecular hydrogen bond.

4 illus, 3 tables, 9 ref

004266   Jagjiwanram;Singh R (Thermal Physics Laboratory, Department of Physics, University of Rajasthan, Jaipur 302 004) : Effective heat storage coefficient of two-phase isotropic systems. Indian J pure appl Phys 2004, 42(4), 283-7.

A theoretical expression for predicting effective heat storage coefficient of two-phase isotropic systems has been developed. The porous system has been assumed to contain particles of irregular shape, being dispersed randomly within the continuous medium. The concept of averaging the temperature field within different phase has been used. The theoretical expresion so obtained predicts values of effective heat storage coefficient quite close to the experimental results.

4 illus, 1 table, 15 ref

004265   Gunasekaran S;Hemamalini R (Department of Physics, Queen Mary's College, Chennai 600 004) : Spectroscopic analysis of the structure of repeat unit of polyethylene terepthalate (PET). Indian J pure appl Phys 2004, 42(4), 246-50.

The proper use of FTIR and laser Raman to study the structure of repeat unit of polyethylene terephthalate (PET) has been presented. A normal co-ordinate analysis of crystalline poly ethylene terephthalate (PET) (trans form) has been carried out. A systematic set of potential constants has been computed using the method of kinetic constants on the basis of C2h symmetry. The potential energy distribution confirms the correctness of the assigmnents made.

3 illus, 1 table, 26 ref

004264   El-Taher A;Mahmoud H M;Abbady A G E (Physics Department, Faculty of Science, Al-Azhar University, Assiut.Egypt) : Multi-element determination of sandstone rock by instrumental neutron activation analysis. Indian J pure appl Phys 2004, 42(4), 243-5.

The instrumental neutron activation analysis technique (INAA) was used in the qualitative and quantitative analysis of sandstone samples from Aswan area in South Egypt. The samples were properly prepared together with their standards and simultaneously irradiated in a neutron flux of 7x10¹¹ n/cm².s in the TRIGA Mainz research reactor facilities. Gamma spectra from hyperpure germanium HPGe detector were analysed. The present study provides the basic data of elemental concentrationsof sandstone rock. The following elements constituents have been determined: Na, K, Fe, Sc, Cr, Co, Zr, Ce, La, Nd, Sm, Eu, Yb, Lu, Hf, Ta, Th and U. The X-ray fluorescence (XRF) was used for comparison and to detect elements which can be detected only by XRF.

5 tables, 9 ref

004263   Dhoble S J;Shahare D I;MOharil S V (Kamla Nehru College, , Sakkardara square, Nagpur 440 009) : Synthesis of CaB₄O₇: Dy phosphor. Indian J pure appl Phys 2004, 42(4), 299-301.

Synthesis of CaB₄O₇:Dy phosphors prepared by solid state diffusion technique has been reported. These are shown to be four times sensitive than the commercially used LiF:TLD100 phosphor. The phosphor has a linear response, negligible fading and excellent reusability. This propertymakes them a suitable replacement for LiF:TLD100 which is currently used for the dosimetry of ionizing radiation using thermo-luminescence.

5 illus, 14 ref

004262   Das G C;Devi K;Sarma J;Devi N (Mathematical Science Division, Institute of Advanced Study in Science & Technology, Khanapara, Guwahati 781 022) : Dynamics and the characteristics behaviour of soliton propagation in dusty plasmas. Indian J pure appl Phys 2004, 42(4), 265-74.

Formation of various solitary waves in a plasma contaminated with dust charged grain have been investigated. Based on pseudopotential analysis, nonlinear Sagdeev potential equation has been derived, from where acoustic modes describing the soliton propagation in dusty plasma have been highlighted. Moreover, for showing the formation of different features of solitions, Sagdeev potential has been expanded due to which different nonlinear wave equations have been formed. It has been shown that the controlling of dust charge composition expects the coexistence of solitons, double layer or shock-like wave along with other nonlinear waves. The catchy of the present investigation has been emphasized to a modified formalism, called tanh-method, in finding the soliton solution from nonlinear wave equations. The success of using tanh-method derives soliton propagation from the Sagdeev potential equation in dusty plasma. Further, other nonlinear modes have been shown which enable to predict the collapse along with the conditions required for its existence.

4 illus, 24 ref

004261   Chatterjee S K;Prasad L C (Department of Chemistry, , M M A M Campus, Biratnagar, Nepal) : Microscopic structure of CuSn compound forming binary molten alloys. Indian J pure appl Phys 2004, 42(4), 279-82.

A simple statistical mechanical theory based on compound formation model (compound A_{μv formed by the preferential arrangement of A and B constituent atoms of the alloy AB, μA + vB = AμBv) has been used to investigate the phenomenon of compound formation in CuSn liquid alloys through the study of microscopic function in CuSn liquid aloys, i.e. concentration fluctuation in long wavelength region {Scc(o)} and chemical short range order parameter (α1). The study explains the observed asymmetry succesfully and suggests the existence of Cu3Sn complex in the melt. The tendency of compound formation has been found to be weak. The system exhibits an ideal behaviour at Sn-rich end. The existence of inter-metallic compound Cu3Sn in the solid phase, which is manifested in the phase diagram, may be one of the factors for the anomalous behaviour of properties of mixing.}

004260   Bakkialakshmi S;Shanthi B;Priyadharsini A (Department of Physics, Annamalai University, Annamalainagar 608 002) : Fluorescence quenching of aniline and p-toluidine by picric acid in methanol. Indian J pure appl Phys 2004, 42(4), 294-5.

The fluorescence quenching spectra of aniline and p-toluidine using picric acid as a quencher in methanol have been studied. The stern-volmer constants for all the quenching processes have been plotted. Regression analysis for stern-volmer plot has been caried out. Regression coefficient (r) and the stern-volmer constant (K_sv) have been calculated. Stoke's shift, ionization potential, electron affinity and the solvent parameter (z) have also been calculated.

1 illus, 2 tables, 6 ref

004259   Ahmed M A;Wasfy M H (Phys Dep, Faculty of Science, , Cairo University) : Effect of charge transfer behaviour on the dielectric and ac conductivity of Co-Zn ferrite doped with rare earth element. Indian J pure appl Phys 2003, 41(9), 731-8.

The dielectric constant ε' and ac conductivity were measured for the ferrite samples Co_1-xZn_xLa_0.25Fe_1.75O₄; 0.1 ≤ x ≤ 0.7 at different temperatures as a function of the applied frequency. The dielectric constant was interpreted on the basis of changing the enthalpy as well as the internal energy of the system. The orientational and rotational polarizations play a significant role in increasing the value of ε' in the second temperature region. The conductivity results give more than one straight line, indicating the different conduction mechanisms. The electron hopping between the iron ions and the hole hopping between the cobalt ions are the main conduction processes in the investigated samples as it was enhanced from the drift mobility data. The values of the activation energy obtained, indicate the semiconducting behaviour of the samples.

7 illus, 1 table, 22 ref

004258   Agrawal S L;Awadhia A (Physics Dep, A.P.S. University, Rewa-486 003) : DSC and conductivity studies on PVA based proton conducting gel electrolytes. Bull Mater Sci 2004, 27(6), 523-7.

An attempt has been made to prepare polyvinyl alcohol (PVA) based proton conducting gel electrolytes in ammonium thiocyanate (NH4₄SCN) solution and characterize them. DSC studies affirm the formation of gels along with the presence of partial complexes. The cole-cole plots exhibit maximum ionic conductivity (2.58 x 10^-3 S cm^-1) for gel samples containing 6 wt% of PVA. The conductivity of gel electrolytes exhibit liquid like nature at low polymer concentrations while the behaviour is seen to be affected by the formation of PVA-NH₄SCN complexs upon increase in polymer content beyond 5 wt%. Temperature dependence of ionic conductivity exhibits VTF behaviour.

3 illus, 1 table, 23 ref

003153   Zolanvari A;Goyal N;Tripathi S K (Phys Dep, Arak Univ, Arak-38156, Iran) : Electrical properties of a-Ge_xSe_100-x. Pramana J Phys 2004, 63(3), 617-25.

In general, the conductivity in chalcogenide glasses at higher temperatures is dominated by band conduction (DC conduction). But, at lower temperatures, hopping conduction dominates over band conduction. A study at lower temperature can, eventually, provide useful information about the conduction mechanism and the defect states in the material. Therefore, the study of electrical properties of GE_xSe_100-xin the lower temperature region (room temperature) is interesting. Temperature and frequency dependence of Ge_xSe_100-x (x = 15, 20 and 25) have been studied over different range of temperatures and frequencies. an agreement between experimental and theoretical results suggested that the behaviour of germanium selenium system (Ge_xSe_100-x) have been successfully explained by correlated barrier hopping (CBH) model.

8 illus, 1 table, 13 ref

003152   Yadav V K;Bora D (Inst for Plasma Res, , Bhat, Gandhinagar-382 428) : Electron cyclotron resonance heating in a short cylindrical plasma system. Pramana J Phys 2004, 63(3), 563-77.

Electron cyclotron resonance (ECR) plasma is produced andstudied in a small cylindrical system. Microwave power is delivered by a CW magnetron at 2.45 GHz in TE₁₀ mode and launched radially to have extraodinary (X) wave in plasma. the axial magnetic field required for ECT in the system is such that the first two ECR surfaces (B + 875.0 G and B = 437.5 G) reside in the system. ECR plasma is produced with hydrogen with typical plasma density n_e as 3.2 x 10¹⁰ cm^-3 and plasma temperature T_e between 9 and 15 eV. Various cut-off and resonance positions are identified in the plasma system. ECR heating (ECRH) of the plasma is observed experimentally. This heating is because of the mode conversion of X-wave to electron Bernstein wave (EBW) at the upper hybrid resonance (UHR) layer. the power mode conversion efficiency is estimated to be 0.85 for this system. The experimental results are presented in this paper.

17 illus, 31 ref

003151   Verma M K;Kumar S (Phys Dep, Indian Inst of Technol, Kanpur-208 016) : Large-eddy simulations of fluid and magnetohydrodynamic turbulence using renormalized parameters. Pramana J Phys 2004, 63(3), 553-61.

In this paper a procedure for large-eddy simulation (LES) has been devised for fluid and magnetohydrodynamic turbulence in Fourier space using the renormalized parameters. The parameters calculated using field theory have been taken from recent papers by Verma. LES on 64³ grid has been carried out. These results match quite well with direct numerical simulation of 128³. Show that proper choice of parameter is necessary in LES.

4 illus, 1 table, 23 ref

003150   Vaidya R;Dave M;Patel S S;Patel S G;Jani A R (Phys Dep, Electronics Dep, Sardar Patel Univ, Vallabh Vidyanagar-388 120) : Growth of molybdenum disulphide using iodine as transport material. Pramana J Phys 2004, 63(3), 53.

In the present paper an attempt has been made to describe the chemical vapor transport (CVT) technique used for the growth of molybdenum disulphide (MoS₂) single crystals. Iodine (I₂) is used as transporting material for this purpose. the energy dispersive analysis by X-ray (EDAX) confirmed the stoichiometry of the as-grown crystals. The lattice parameters of these crystals were determined from the X-ray diffraction analysis. The grown crystals were examined under the optical zoom microscope for their surface microstructure study.

3 illus, 4 tables, 20 ref

003149   Uthanna S;Mohan Babu P;Rao G V (Phys Dep, sri Venkateswara Univ, Tirupati-517 502) : Bias magnetron sputtered indium oxide films : structural and electrical properties. Bull Indian Vacuum Soc 2004, 7(2), 17-21.

Thin films of indium oxides were deposited on glass substrates by dc reactive magnetron sputtering from metallic indium target in an oxygen partial pressure of 2 x 10^-1 mbar and at various substrate bias voltages in the range 0 to 100 V. The influence of substrate bias voltage on teh structural and electrical properties was systematically studies. the films formed at 303 K without bias voltage were amorphous in nature while those deposited with substrate biasing and / or heating were polycrystalline with bixbyte structure. Low electrical resistivity of 1.8 x 10^-3 Ω cm was achieved in the case of the films prepared at a substrate temperature of 473 K and bias voltage of -100V.

4 illus, 12 ref

003148   Turgut U (K K Education Faculty, Phys Dep, Ataturk Univ, 25240 Erzurum, Turkey) : Chemical effect on the K shell fluorescence yield of Fe, Mn, Co, Cr and Cu compounds. Pramana J Phys 2004, 63(5), 969-75.

Chemical effects on the K shell fluorescence yield of Fe, Mn, Co, Cr and Cu compounds were investigated. Samples were using 59.5 keV energy photons from a ²⁴¹Am radioisotope source. K X-rays emitted by samples were counted by a Si(Li) detector with a resolution 16 eV at 5.9 keV. Chemical effects on the K shell fluorescence yields (wk) for Fe, Mn, Co, Cr and Cu compounds were observed. The values are compared with theoretical, semiempirical fit and experimental ones for the pure elements.

2 illus, 2 tables, 20 ref

003147   Tsuwi J K;Merenga A S;Katana G;Papadakis C M (Physics Department, Kenyatta University, P.O. Box 438444, Nairobi, Kenya) : Dynamic mechanaical analysis of injection molded untreated and treated talc-filled high-density polyethylene composites. J Polym Mater 2003, 20(4), 355-60.

The mechanical properties above glass transition temperature of untreated and silane-treated injection-molded talc-filled high-density polyethylene (HDPE) composites have been studied have been studied using dynamic mechanical analysis (DMA) in the rane of 0.5 to 25 Hz at 298 to 353 K. The silane treatment of the filler as well as the injection process induce a structure, resulting in inhomogeneity and anisotropy for the molded discs. Differential scanning calorimetry (DSC) is used to justify the macroscopic properties measured with DMA.

8 illus, 2 tables, 15 ref

003146   Tomecek P;Horakova V;Lapcik L (Physics and Material Engineering Dep, Tomas Bata University in Zlin, Nam. T.G.M. 275, 762 72 Zlin, Czech Rep, ) : The effect of various fillers on the cure behavior of an epoxy system. J Polym Mater 2003, 20(4), 399-402.

An effect of filler on the reaction kinetics of epoxy system cured with diethylenetriamine has been studied usig differential scanning calorimetry. Various kinetic models, including homogeneous reaction, diffusion reaction, surface and autocatalytic reactions, have been tested. Kinetic analysis using integral and derivative procedures from the data indicates that the curing reaction can be well described with the autocatalytical and first-order homogeneous reactions model.

4 illus, 1 table, 7 ref

003145   Tiwary S N;Kumar R (Univ Dep Phys and Univ Dep of Electronics, BRA Bihar Univ, Muzaffarpur, Bihar) : Photoionizations of He(1s<. Indian J Phys 2004, 87(10), 1095-8.

The possibility of using the correlated double-continuum wavefunction (DCWF) proposed by Brauner, Briggs and Klar (BBK) for the final state and full configuration interaction (CI) wavefunction generated by Tiwary for the ground state to calculate the double photoionization cross section (DPICS) of atomic systems, is investigated. The helium atom is considered as a test system. Comparison is made with available experimental observations and other theoretical predictions. The results of our investigation show that the impact of the BBK DCWF and improved BBK DCWF on the DMCS of He is encouraging.

1 illus, 26 ref

003144   Tewari S;Das R;Chakraborty A;Bhattacharjee R (Phys Dep, Natnl Inst of Technol, Silchar-780 010) : Resonance raman study on distorted symmetry of porphyrin in nickel octaethyl porphyrin. Pramana J Phys 2004, 63(5), 1073-82.

The resonance Raman (RR) spectra of nickel octaethyl porphyrin, Ni(OEP), in CH₂Cl₂ (solvent) at different excitations such as 544.5, 488.0, 441.6 and 406.7 nm are recorded and analysed. The results of the theory of distortion-induced RR intensity is applied to the observed spectra to determine the excited electronic state symmetry of prophyrin in Ni(OEP). It is concluded that the porphyrin molecule (D_4h structure) attains a non-polar distored structure of D₂ symmetry rather than S₄ symmetry in CH₂Cl₂ solution.

3 illus, 2 tables, 56 ref

003143   Tagiyeva R T (Inst of Phys, Azerbaijan Natnl Academy of Sci, Baku AZ 1143, Azerbaijan) : Dispersion relation for localized magnetic polaritions propagating at the junction of two ferromagnetic/non-magnetic superlattices. Pramana J Phys 2004, 63(3), 633-41.

Localized magnetic polaritons are investigated in the systems consisting of two magnetic superlattices, coupled by a ferromagnetic contact layer. The general dispersion relation for localized magnetic polaritions are derived in the framework of the electromagnetic wave theory in the voigt geometry by the `transfer' matrix method. The numerical calculations were carried out for different parameters of the superlattices and contact layer.

4 illus, 33 ref

003142   Srivastava M K (Inst Instrumentation Centre, Indian Inst of Technol, Roorkee-247 667) : Scaling of cross-sections for asymmetric (e-3e) process on helium-like ions by fast electrons. Pramana J Phys 2004, 63(5), 1053-62.

An approximate simple scaling law is obtained for asymmetric (e, 3e) process on helium-like ions for double ionization by fast electrons. It is based on the equation (Z'³/π) exp[-Z'(r1 + r2)] Z' = Z - (5/16) for ground state wave function of helium like ions and Z'² scaling of energies. The scaling law is found to work very well if the lower energy electron is ejected along the momentum transfer direction and the other one is ejected in the opposite direction. It also works quite well if this electron is ejected within about 90° of the momentum transfer direction with other electron going in the opposite direction. The scaling law becomes increasingly accurate as the target nuclear charge and the energy increase.

7 illus, 15 ref

003141   Singh N (Optics Group, Raman Res Inst, , Bangalore-560 080) : Relaxation between electrons and surface phonons of a homogeneously photoexcited metal film. Pramana J Phys 2004, 63(5), 1083-7.

The energy relaxation between the hot degenerate electrons of a homogeneously photoexcited metal film and the surface phonons (phonon wave vectors in two dimensions) is considered under Debye approximation. The state of electrons and phonons is described by equilibrium Fermi and Bose functions with different temperatures. Two cases for electron scattering by the metal surface, namely specular and diffuse scattering are considered.

1 illus, 12 ref

003140   Singh K;Kaur A (Phys Dep, Guru Nanak Dev Univ, Amritsar-143 005) : Estimation of thermal conductivity and thermal diffusion in gas mixtures. Indian J Phys 2004, 87(10), 1111-14.

Semi-empirical expressions for the higher-order contributions to the transport coefficients in a gas mixture have been compared with the general expressions. Comments on their use in estimation of thermal diffusion and thermal conductivity of a multicomponent gas mixture have been given.

1 illus, 2 tables, 13 ref

003139   Singh D P;Bhatti S S (Appl Phys dep, Guru Nanak Dev Univ, Amritsar-143 005) : Study of ultrasonic properties of orthorhombic and tetragonal RBaCuO (R = Y, Gd, Dy) compound. Indian J Phys 2004, 87(10), 1107-9.

RBaCuO (R = Y, Gd, Dy) compound in the orthorhombic form is a high temperature superconductors. This compound was prepared in orthorhombic as well as in tetragonal form. Beside resistivity measurements, ultrasonic measurements were made using pulse-echo-overlap method at 5 MHz in the system up to liquid nitrogen temperature. Results are discussed as a function of component R, oxygen content and temperature.

9 illus, 1 table, 11 ref

003138   Sequeira J (Low Temperature Facility, Tata Inst of Fundamental Res, Colaba, Mumbai-400 005) : Vacuum re-conditioning of cryogenic dewars. Bull Indian Vacuum Soc 2004, 7(2), 3-14.

Cryogenic dewars which store liquid nitrogen or helium, need reconditioning for their vacuum when their performance goes bad. This article describes some of the procedures adopted for the reconditioning of vacuum and the successful revival of many dewars at Low Temperature Facility, TIFR, Mumbai.

7 illus

003137   Saxena S;srivastava R (Physics Dep, Indian Inst of Technol, Roorkee-247 667) : Electron excitation of the D states of the alkaline earth atoms. Indian J Phys 2004, 87(10), 1085-93.

Uses distorted wave (DW) approximation theory to study the excitation of the few lower excited n^1.3D states of Ca(n=4, 5) and Sr(n=5,6) from their ground state. Hartree-Fock wave functions obtained from Fischer's Code are used to represent the ground and excited states of the Ca and Sr atoms as well as to generate the distortion potentials for the projectile continuum electron distorted waves. Results for Stokes parameters are calculated at electron impact energies of 20 and 40 eV. Good agreement has been found on comparison with the relativistic distorted wave calculations.

4 illus, 10 ref

003136   Saxena S;Muktavat K;Srivastava R (Phys Dept, Indian Inst of technol, Roorkee-247 667) : Electron impact excitation of the D states of Mg, Ca and Sr atoms: complete experiments results. Pramana J Phys 2004, 63(5), 977-91.

Used non-relativistic and relativistic distorted wave approximation methods to study the excitation of the n¹D states of magnesium (n = 3), calcium (n = 4) and strontium (n = 5) from the ground n¹ state. Calculations have been performed for the complete set of parameterss (σL⁺_{<94>,L^-<94>< F255>, γ⁺, γ^-). The results are presented for electron impact energies of 20 and 40 eV. Results obtained from both the non-relativistic and relativistic methods were compared with each other. Good agreement is found on comparison and the importance of relativistic effects is also explored.}

9 illus, 21 ref

003135   Saraykar R V;Patil K D (Math dep, Nagpur Univ Campus, Nagpur-440 033, Email: kishordpatil@yahoo.com) : Necessary conditions for the occurrence of a naked singularity in higher dimensional dust collapse. Indian J Phys 2004, 87(10), 1151-6.

Analyses higher dimensional non-marginally bound inhomogeneous dust collapse where initial data consists of finitely differentiable functions of comoving coordinate r. Shows that with the introduction of a velocity distribution function, the results on the occurrence on a naked singularity get slightly modified in comparison with the marginally bound collapse. Also discussed the nature of families of radial null geodesics coming out from the singularity.

14 ref

003134   Sandhu B S (Phys Dep, Punjabi Univ, Patiala-147 002) : Energy and intensity distributions in double-photon compton scattering. Indian J Phys 2004, 87(10), 1061-5.

The scattering process of a single incident photon by an electron into a final state consisting of two simultaneously emitted photons is called double-photon Compton scattering. The theory and elementary features of this higher order process are described. The reported experimental measurements so far on this higher order process, demonstrate conclusively its existence. Some elementary features of the theory of this process have also been confirmed in some of the measurements.

18 ref

003133   Salem M A;El-Ahdal M A;Hussein A (Physics Dep, Faculty of Science, Azhar University, , Nasr-City, Cairo, Egypt) : Study of the effect of gamma irradiation on carbon black loaded low-density polyethylene films. J Polym Mater 2003, 20(4), 361-5.

The effect gamma irradiation on the tensile and physico-chemical properties of low-density polyethylene (LDPE) films loaded with different concentrations of carbon block (C.B) has been studied. The results showed that the behaviour of the samples during gamma irradiation is complicated and the interaction between oxidation and crosslinking processes. The tensile properties are modified by the presence of carbon black. Film sample containing 7% C.B was found to exhibit a nearly stabilized tensile behavior with radiation dose, which allows to use this formulation in packaging for food sterilization and in preservation of weak cobalt-gamma sources.

7 illus, 20 ref

003132   Sahoo S;Maharana L (Phys dep, Natnl Inst of Technol, Durgapur-713 209) : Flavour-changing neutral currents in models with extra Z' boson. Pramana J Phys 2004, 63(3), 491-507.

New neutral gauge bosons Z' are the features of many models addressing the physics beyond the standard model. Together with the existence of new neutral gauge bosons, models based on extended gauge groups (rank <62> 4) often predict new charged fermions also. A mixing of the known fermions with new states, with exotic weak-isospin assignments (left-handed singlets and right=handed doublets) will induce tree-level flavour changing neutral interactions mediated by Z exchange, while if the mixing is only with new states with ordinary weak-isospin assignments, the flavour-changing neutral currents are mainly due to the exchange of the new neutral gauge boson Z'. Review flavour changing neutral currents in models with extra Z' boson.

1 tables, 44 ref

003131   Sahni V C (Centre for Advanced Technol, , Indore-452 013) : Indian contribution to the large hadron collider under construction at CERN, Geneva. Curr Sci 2004, 87(4), 441-6.

India is participarting in the construction of the Large Hadron Collider (LHC), which is the most ambitious particle accelerator being built by CERN. We describe the Indian contribution to the LHC, in terms of both hardware and software and also in terms of skilled manpower support made available for evaluation of some of the LHC sub-systems over the past few years.

4 illus, 1 table

003130   Ray H (Phys Dep, Indian Inst of Technol, Roorkee-247 667) : Studies on ionization and excitation processes in Ps-Li scattering. Pramana J Phys 2004, 63(5), 1063-72.

Three different types of ionization and excitation processes are studied in detail for the scattering of positronium (Ps) by the simples alkali atom (Li) using a Coulomb-Born approximation for ionization and first-Bron approximation for excitation. This is the first work where orthogonalized Coulomb wave is used to represent the ionized electron for Ps-Li scattering using a single-electron and a three-electron prescription of the target. Li is chosen to minimize the effect of intrinsic correlation among the target atomic electrons so that it can extract the basic physics more accurately. All the possible Coulomb interactions are considered exactly. Comparative studies of different cross-sections using two different representations of the target provide us the informations to enrich ideas about the system and the important role of core electrons.

5 illus, 23 ref

003129   Rao B S;Ramakrishna K;venkateswaralu P (Chem Dep, Coll of Engng, GITAM, Visakhapatnam-530 045) : New simultaneous method for the determination of cobalt (II) and copper (II) by atomic absorption spectrometry in industrial effluents and some fruits. Indian J envir Prot 2003, 23(10), 1141-5.

A new reagent, potassium benzyl xanthate (KBX) has been introduced for the preconcentration and simultaneous determination of cobalt (II) and copper (II) by atomic absorption spectrometry. The new method is simple, rapid and sensitive. A number of associated elements do not interfere in the determination. The selectivity of the reagent is also improved by using suitable masking agents, to suppress the interference of some metal ions, like iron (III) and lead (II). Aliquots containing 5 μg/mL of cobalt (II) and coppr (II) gave a standard deviation of 0.1549 x 10³, 0.238x10³, respectively and co-efficient of variance is 0.3450 and 0.2549%, respectively. the sensitivity was found to be 6.1775 ng/mL for cobalt (II) and 3.1629 ng/ml for copper (II). the authors recommend the new method for the preconcentration and simultaneous determination of cobalt (II) and copper (II) by AAS, at minor and trace levels, besides its use to analyse real samples, such as industrial effluents and some fruits.

1 illus, 5 ref, 14 ref

003128   Purohit G;Choubisa R;Sharma D K;Sud K K (Phys Dep, Coll of Sci Cmpus, M L S Univ, Udaipur-313 002) : Electron impact single and double ionization of he-like ions. Indian J Phys 2004, 87(10), 1067-72.

Presents the results of calculation of TDCS and FDCS of (e.2e) and (e,3e) processes respectively on the He-like ions at incident electron energy of 1099 eV. Performed the calculation using distorted wave Born approximation (DWBA) formalism for (e, 2e) process and three Coulomb (3C) wave approach for (e, 3e) process in shake-off mechanism. Presents the angular profiles of TDCS in coplanar asymmetric geometry as well as that of FDCS in constant θ mode and discuss the role of atomic number Z on it. The similarities and dissimilarities between (e, 2e) and (e,3e) processes of He-like ions has also been discussed.

3 illus, 11 ref

003127   Patidar V;Sud K K (Phys Dep, coll of Sci Campus, M L S Univ, Udaipur-313 002, Raj) : Creation of periodic and chaotic attractors using blending technique. Indian J Phys 2004, 87(10), 1115-20.

Demonstrates that by using blending of chaotic attractor with a limit cycle attractor generated by the similar system operating in the periodic regime of oscillations (may be weak, period-1, period-2 etc), one can create various periodic and chaotic attractors having properties intermediate between the chaotic and periodic attractors, which were initially used for the blending mechanism. Basically it is the matual coupling mechanism between the phase variables of chaotic and periodic oscillators of same kind, which does not rely on the knowledge of the system model equations and the system parameters are not changed explicity. The technique is expected to be useful for those physical systems in which direct accessibility of its parameters is either difficult or not possible. Presents the results of numerical simulations of Duffing oscillator and Jerk dynamical systems, which represent the plasma oscillation and WINDMI model of the earth's magnetosphere respectively.

3 illus, 22 ref

003126   Pal A;Stokes D L;Vo-Dinh T (Civil Engng Dep, Indian Inst of Technol, Kharagpur-721 302) : Photochemically prepared gold metal film in a carbohydrate-based polymer: a practical solid substrate for surface enhanced Raman scattering. Curr Sci 2004, 87(4), 486-91.

A method for the preparation of thin gold film on glass slides has been described. When thin films of methylcellulose containing chloroauric acid are irradiated in a photoreactor under UV light, they produce a clear gold mirror made of aggregated gold particles stabilized by methylcellulose. The metal film can be used as a practical substrate for surface-enhanced Raman scattering. The substrate is stable and easy to prepare.

3 illus, 49 ref

003125   Okieimen F E;Akinlabi A K;Aigbodion A I (Chemistry Dep, University of Benin, Benin City, Nigeria) : Processing characteristics and physico-mechanical properties of thioglycollic acid modified epoxidized low molecular weight natural rubber and its blends with natural rubber. J Polym Mater 2003, 20(4), 403-8.

Low molecular weight natural rubber (LMWNR) obtained by depolymerization natural rubber latex (NRL) was modified by epoxidation to 35% epoxide level to yield epoxidised low molecular weight natural rubber (ELMWNR). This product was in turn modified in solution of thiotglycollic acid (TGA) (0.5 mol phr) to yield a product of 20% conversion of its initial LMWNR epoxide. The epoxidized low molecular weight natural rubber-thioglycollic acid adduct (ELMWNR-TGA) obtained was blended with NR in various proportions. The processing behavior and cure characteristics of the vulcanizates of the blends were carried out with Mooney viscometer and Oscillating Disc Rheometer. The physico-mechanical properties of the vulcanizates were measured. The tensile strength, crosslink densities, Mooney viscosity, scorch time, hardness, and abrasion resistance decrease as the ELMWNR-TGA concentration of the mix increases. However, vulcanizates with higher concentrations of ELMWNR-TGA show better resistance to selling in methanol and mineral oils. Properties of the vulcanizates containing 5-15 phr of ELMWNR-TGA are similar to those of NR but they have better solvent resistance.

5 tables, 25 ref

003124   Nandi T (Nuclear Sci centre, Jawaharlal Nehru Univ, Aruna Asaf Ali Marg, New Delhi-110 067) : Recent interest in physics of Li-like ions for Z = 20-30. Indian J Phys 2004, 87(10), 1045-9.

The research program on lifetime measurements of metastable states in He- and Li-like ions in the region Z = 20-30 has been progressing well at. The beam-foil spectroscopy with single as well as two-foil involving an X-ray solid state deterctor has resolved intricate problem of state llite line, and in turn, it has provided as reliable lifetime of both the upper levels of He- and Li-like M2 lines. In order to resolve the satellite from He-like M2 line spectrally, Doppler Tuned Spectrometer (DTS) have been developed. So far, work has been centered around the 15UD Pelletron accelerator. High current ECR ion source-based injection to the forthcoming LINAC will be more appropriate for above mentioned works. Present activities and future plans of high resolution experiments will be highlighted along with the salient results obtained.

4 illus, 1 table, 22 ref

003123   Mutuku J N;Karanja P K (Physics Dep, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 6200, Nairobi, Kenya) : Mechanical and thermal properties of lodine doped polypropylene films. J Polym Mater 2003, 20(4), 445-52.

Mechanical and thermal properties of iodine-doped commercial polypropylene (PP) films have been studied. Differential scaning calorimetry and dynamic mechanical analysis (DMA) techniques were used for the study. The crystalline melting point of iodine-doped PP was found to be 43.7°C more than that of virgin PP. Storage and loss compliances increased by 70°C. A ratio of 8.8 x of storage modulus for doped to undoped PP sample at 20 Hz was obtained. Photoacoustic spectroscopy and Fourier transform infrared (FTIR) spectrophotometry were used for structural investigation.

7 illus, 15 ref

003122   Moorti A;Raghuramaiah M;Naik P A;Gupta P D (Laser Plasma Div, Centre for Advanced Technol, Indore-452 013) : Characteristics of a multi-keV monochromatic point x-ray source based on vacuum diode with laser-produced plasma as cathode. Pramana J Phys 2004, 63(5), 1031-7.

Temporal, spatial and spectral characteristics of a multi-keV monochromatic point x-ray source based on vacuum diode with laser-produced plasma as cathode are presented. Electrons from a laser-produced aluminium plasma were accelerated towards a conical point tip titanium anode to generate K-shell x-ray radiation. approximately 10¹⁰ photons/pulse were generated in x-ray pulses of ~ 18 t ~ 28 ns duration from a source of ~ 300 μm diameter, at hv = 4.51 (K_α emission of titanium), with a brightness of ~ 10²⁰ photons/cm²/s/sr. This was sufficient to record single-shot x-ray radiographs physical objects of a DEF-5 x-ray film kept at a distance of up to ~ 10 cm.

6 illus, 18 ref

003121   Mondal K K (Phys Dep, raja Peary Mohan Coll, Uttarpara, Hooghly-712 258) : Propagation of dust-acoustic waves in weakly ionized plasmas with dust-charge fluction. Pramana J Phys 2004, 63(5), 1021-30.

For an unmagnetized partially ionized dusty plasma containing electrons, singly charged positive ions, micron-sized massive negatively charged dust grains and a fraction of neutral atoms, dispersion relations for both the dust-ion-acoustic and the dustacoustic waves have been derived, incorporating dust charge fluctuation. The dispersion relations, under various conditions, have been exhaustively analysed. The explicit expressions for the growth rates have also been derived.

2 illus, 12 ref

003120   Misra A P;Roy chowdhury A;Paul S N (High Energy Phys Div, Phys Dep, Jadavpur Univ, Kolkata-700 032) : Higher order contribution to the propagation characteristics of low frequency transverse waves in a dusty plasma. Pramana J Phys 2004, 63(3), 579-93.

Characteristic features of low frequency transverse wave propagating in a magnetised dusty plasma have been analysed considering the effect of dust-charge fluctuation. The distinctive behaviours of both the left circularly polarised and right circularly polarised waves have been exhibited through the analysis of linear and non-linear dispersion relations. The phase velocity, group velocity, and group travel time for the waves have been obtained and their propagation characteristics have been shown graphically with the variations of wave frequency, dust density and amplitude of the wave. The change in non-linear wave number shift and Faraday rotation angle have also been exhibited with respect to the plasma parameters. It is observed that the effects of dust particles are significant only when the higher order contributions are considered. This may be referred to as the `dust regime' in plasma.

9 illus, 26 ref

003119   Mabrouk M A;Sadik A M (Physics Dep, Faculty of Science, , New Demietta, Egypt) : Measurement of polymeric fibers optical properties by the use of automatic fourier and interferometric techniques. J Polym Mater 2003, 20(4), 387-97.

The optical fourier transform and fringe field microinterferograms of birefringent polymeric fibers are processed with two different computer-controlled automatic analysis systems to extract required data. Single- and multi-fringe and fringe field methods are used to determine the birefringence spectral dispersions of highly oriented polymeric fibers. The advantages for automatic data extraction are pointed out.

6 illus, 9 ref

003118   Kumar S;Bhasin V S (Phys and Astrophysics Dep, Univ of Delhi, Delhi-110 007) : Three-body analysis of <. Pramana J Phys 2004, 63(3), 509-28.

10 illus, 2 tables, 33 ref

003117   Kulhar V S (NO, Univ of Rajasthan, Jaipur-302 004) : Muonium/muonic hydrogen formation in atomic hydrogen. Pramana J Phys 2004, 63(3), 543-51.

The muonium/muonic hydrogen atom formation is μ±-H collisions in investigated, using a two-state approximation in a time dependent formalism. It is found that muonium cross-section results are similar to the cross-section results obtained for positronium formation in e⁺-H collision. Muonic hydrogen atom formation cross-sections in μ^--H collision are found to be significant in a narrow range of energy (5 eV-25 eV).

6 illus, 1 table, 21 ref

003116   Kucukbursa A;Salamov D I;Babacan T;Aygor H A (NO, , ) : An investigation of the influence of the pairing correlations on the properties of the isobar analog resonances in A = 208 nuclei. Pramana J Phys 2004, 63(5), 947-61.

4 illus, 2 tables, 25 ref