019047   Bhattacharya M;Shambhunath Singh W; Dorendrajit Singh S;Ghosh S;Mazumdar P S (Physics Dep, Krishnath College, Berhampore-742 101) : Computerised glow curve deconvolution of pure NaCl, NaCl:I and common salt of Manipur using mixed order kinetics model. Indian J Phys 2006, 80(10), 975-8.

Computerised Glow Curve Deconvolution (CGCD) of experimental complex thermoluminescence (TL) peaks of Pure NaCl, NaCl:I and common salt of Manipur 'Meitei Thurn' irradiated with γ1.01 kGy) is carried out using mixed order (MO) kinetics model. Each complex peak is observed to have four component peaks.

4 illus, 1 table, 19 ref

019046   Bhagat S K (NO, , Baigana, P.O.: Ganeshpur Purnea-854 301) : Analysis of fourier transforms of quasi-crystals. Acta Cienc Indica-Phys 2006, 32(2), 253-6.

Analysis of Fourier transforms of Quasi-crystals has been presented. For quasilattice diffraction a more important factor would be the effect of the quasilattice itself other than regular-lattice equivalent terms that give the transforms in a closed form involving structure factor, quasilattice factor and kinematic factor. In addition to these three additional problem in the case of electron diffraction. Also the subtle deviations between icosdhedral model and twin models are usually extremely small and theoretical/semitheoretical computation of Fourier transform should be rigorously carried out before any reasonable claim could be made concerning peak-shift effects. The diffraction pattern has been already calculated from different finite segments of quasilattice having the same width and number of scatteres. The peak-positions have been numerically calculated starting from the positions where the peaks would occur in the diffraction from an ideal quasilattice with the smallest interval possible (10^-6) and then locating the maxima nearest to them. Although the width is the same, the peak positions have been found to shift which cannot be explained by the slit-function. This clearly indicates that the arrangement of scatterers plays a crucial role in determining the diffraction pattern. In the 2-dimen-sional case, it has been pointed out that only scatterers lying in the circular region were used in the Fourier transform calculations.

8 ref

019045   Bhagat S K (NO, , Baigana, P.O: Ganeshpur) : Spiral growth model for quasicrystals. Acta Cienc Indica-Phys 2006, 32(2), 141-4.

Spiral growth model for quasicrystals finds interesting role in crystallography. The conventional crystallography has been a well known model for crystal growth. Spiral things have also been considered in other contexts. Here one should mention a few other aspects of two dimensional spiral stacking of rhombuses which could be relevant to quasicrystal growth. Spiral growth will imply a local minimization of surface free energy. From the theory of tiling models one would believe that the staircase-like local ordering will contribute to the configu-rational entropy of the quasicrystal. Spiral ttilings will result in well defined morphologies and staircae-like features. Such staircases have indeed been observed recently. The formation of quasi-icosahedral spiral shapes in carbon particles during growth has been recently found in micrographs and their models in three dimensions possessed both icosahedral and helical features.

3 table, 16 ref

019044   Bera P K;Datta J (Phys Dep, Dumkal Coll, Basantapur, Dumkal, Murshidabad-742 303, Email: pbera321@sify.com) : Spectral inverse problem for q-deformed harmonic oscillator. Pramana J Phys 2006, 67(6), 1023-35.

Supersymmetric quantization condition is used to study the wave functions of SWKB equivalent q-deformed harmonic oscillator which are obtained by Using only the knowledge of bound-state spectra of q- deformed armonic oscillator. Also studies the nonuniqueness of the obtained interactions by this spectral inverse method.

24 ref

019043   Banerjee N (Relativity and Cosmol Res Centre, Phys Dep, Jadavpur Univ, Kolkata-700 032) : Accelerated expansion of the universe and scalar tensor theory of gravity. Indian J Phys 2006, 80(11), 1097-1100.

Possible role of a scalar field, non minimally coupled to gravity, in the search for dark energy is very briefly reviewed. Some possibilities in the framework of Brans-Dicke theory are discussed.

14 ref

019042   Bakkialakshmi S;Shanthi B;Kavitha S (Centralised Instrumentation and Services Laboratory (CISL), Annamalai Univ, Annamalainagr-608 002) : Evaluation of aniline with picric acid and formic acid under controlled condition. Acta Cienc Indica-Phys 2006, 32(2), 197-200.

The fluorescence of aniline at room temperature is polluted by the addition of picric acid and formic acid. The Stern-Volmer constants and the regression coefficient are reported. Ionization potential, electron affinity and the solvent parameter are calculated. The reduction by molecules containing only electron donating substituents involves a charge transfer complex.

3 illus, 2 table, 2 ref

019041   Arjun Kumar (NO, , Adarsh Nagar, Ward No.9 Madhipura (Bihar)) : Quantum mechanical analysis of Bohr's complementary principle. Acta Cienc Indica-Phys 2006, 32(2), 169-72.

Quantum mechanical explanation for Bohr complementary principal has been presented. It is noted that the absence of interference in a detection process is due to decoherence arising from-entanglement of interfering wave function branches with orthogonal detector states. The de-tector essentially has a quantum character and has degree of freedom that get entangled with the system under observation in the larger Hilbert space of the total wave Junction. The entangled wave function gets irreversibly collapsed to either of the two wave function branches when which-slit information is read out from the detector. A comprehensive treatment of a macroscopic observation, however, would require a large multiparticle system and two essen-tial ingredients of measurement such as amplification and irreversibility.

9 ref

019040   Anirudh Kumar (Physics Dep, R.B College, Dalsingsari-848 114) : H-plane sectoral dielectric corrugated wall horn. Acta Cienc Indica-Phys 2006, 32(2), 201-8.

A comparative study between the plane horn and corrugated one, having the same length ana flare angle has been devoted. The different characteristic behaviours have been shown in figures. It can be easily observed that corrugated structure has reduced the beam width. Corrugation has also improved input SWR and the gain of the horn antenna. The aperture distribution of the field as a function of substance has also been shown in the figure, which indicated that the fall of power from side falls towards the centre is more steeper in corrugated horn as compared to plane horn.

9 illus, 4 ref

019039   Alok Kumar (NO, Inst of Phys, Bhubaneswar-751 005, Email: kumar@iopb.res.in) : AdS gravitational waves in string theory. Indian J Phys 2006, 80(11), 1101-7.

AdS graviational wave solutions and some of their properties, in pure gravity theory, are briefly reviewed. Similar solutions and their symmetry properties are then discussed in string and M-theory, as classical solutions of low energy effective actions.

14 ref

019038   Agashe S D;Agashe S S;Ghatol A A (Instrumentation & Control Dep, Govt. College of Engineering, Pune-5) : Model heat exchanger automation. J Instrum Soc India 2006, 36(3), 168-73.

Heat exchange is a complex process, which is having capacity and a time lag as process elements. The proposed system is a typical pipe-in pipe-type² heat exchanger. The complexity of the system demands careful selection, proper installation and commissioning. The two accepted control strategies often used are feedback approach and other a feedforword approach. The temperature, flow, and pressure sensors play a vital role in the control performance. The final control element used is a pneumatically operated control valve. The results obtained are encouraging and revealing the fact that if the process details are known completely as far as process parameters are concerned and utilities are well stabilized then the feed forward strategy can be effectively employed and in all other situations feedback will be the only choice. After careful selection of sensors installation demands precise workmanship. The proposed set up has been implemented as an Educational Aid to give better insight in functioning of the heat exchanger and the manipulating control strategies.

5 illus, 4 tables, 3 ref

019037   Acharya M;Singh L P;Dash G C (Phys Dep, Coll of Basic Sci and Humanities, Orissa Univ of Agric and Technol, Bhubaneswar-751 003) : Non-parallel vortex instability of natural convection flow over a non-isothermal inclined flat plate with simultaneous thermal and mass diffusion. Indian J Phys 2006, 80(10), 989-1004.

Analysis is performed to study the heat mass transfer and non-parallel vortex instability characteristics of buoyancy induced flows that result from simultaneous diffusion of heat and mass on laminar boundary layers adjacent to horizontal and inclined surfaces with variable surface temperature T_w(x) - T∞ = Axⁿ, where n is a constant to be taken as 0,1/3 or I. Numerical results are obtained for a Prandtl number of 0.7 over a range of Schmidt numbers and various angles of inclination from the horizontal φ. The preparation of solution algorithm with the recursion formulae becomes tedious for system of first order equations to be solved with block elimination method. Therefore, matrix-solver algorithm [26] is used to perform matrix operations required in the block elimination method. For a given angle φ, it is found that when the two buoyancy forces from thermal and mass diffusion act in the same direction, both the surface heat and mass transfer rates increase causing the flow to become more susceptible to the vortex mode of instability. However, the fluid flow becomes stable when the two buoyancy forces act in the opposite directions. On the other hand, as φ is increased, the heat and mass transfer rates are enhanced but instability of the flow to the vortex mode of disturbance decreases and eventually vanishes at φ =90 deg. Results from the present non-parallel flow analysis are compared with the available experimental data. It is observed that present calculation is close to experimental data.

9 illus, 2 tables, 32 ref

017985   Wary G;Kachary T;Rahman A (Physics Dep, Cotten College, Guwahati-781 001) : Thermal and doping effect on photovoltaic behaviour of h-treated (n)zno/(p)cdte heterojunctions. Indian J pure appl Phys 2006, 44(10), 754-8.

The thin film (n)ZnO/(p)CdTe heterojuctions with different doping concentrations were prepared by vacuum evaporation and their electrical and optical properties, both in dark and under illumination at room temperature as well as at elevated temperatures were studied. The structures showed change of photovoltaic (PV) effect, giving fill factor 0.59 for H-treated sample with open-circuit voltage 368 mV and short-circuit current density 76.38x10^-4 mA/cm² and for untreated sample 0.46 with open-circuit voltage 250mV and short-circuit current density 57.11xl0⁴ mA/cm² for doping concentration N_a=1.30xl0¹⁷/cm³ (4.90% Sb doped CdTe) and N_d=3.33x10¹⁷/cm³(4.25% Al doped ZnO). The variations of PV efficiency at room temperature with respect to these, doping concentrations were shown to be the optimal value of this typical (n)ZnO/(p)CdTe junction. The fill factor has been found to increase with temperatures showing a maximum value around 343K for H-treated and 335K for untreated samples. The proper doping, annealing and hydrogenation are necessary to reduce the series resistance so as to achieve an ideal and high efficiency PV converter.

5 illuse, 2 tables, 15 ref

017984   Tripathi B;Mangal R K;Wate S;Vijayvargiya J K;Kulshrestha V;Awasthi K;Singh M;Vijay Y K (Physics Dep, Rajasthan Univ, Jaipur-302 004) : Positron lifetime study in FeCl₃ doped polusulphone polymer. Indian J pure appl Phys 2006, 44(10), 763-6.

Positron lifetime measurements were performed on FeCl₃ doped polysulphone (PSF) samples. As the doping % of FeCl₃ increases the lifetime components τ₁ (p-Ps), and τ₃ (o-Ps) decrease, while intensity component (I₃) increases. It-was found that the hole size and the total free volume fraction decrease with FeCl₃ concentration, in polymeric membranes. There may be the cause of formation of FeCl₃ clusters in polymeric chains, the FeCl₃ clusters increase the cross-linking between polymeric chains. The optical measurements were also performed on these samples from which it is clear that on increasing the doping of FeCl₃, the absorption increases.

2 illuse, 1 table, 11 ref

017983   Tanwar A;Gupta K K;Singh P J;Vijay Y K (Physics Dep, M S J college, Bharatpur-321 001, Email: tanwar17msj@yahoo.com) : Microwave dielectric relaxation study of poly (methyl methacrylate and polysulphone in dilute solutions. Indian J pure appl Phys 2006, 44(7), 548-53.

Dielectric relaxation studies of poly (methyl methacrylate) in dilute solutions of benzene and 1,4-dioxane and polysulphone in dilute solutions of 1,4-dioxane have been carried out at 8.92 GHz and temperatures 30, 40, 50, 60°C, respectively. Average relaxation time τ₀, and relaxation times corresponding to group rotation τ(1) segmental motion τ (2) and dipole moment μ have been determined. The results have been interpreted by the internal and hindered rotation of ester group and sulphone unit for PMMA and polysulphone, respectively. The study reveals the existence of both, the intramolecular and overall orientations in PMMA and polysulphone. Thermodynamic parameters, viz. free energy, enthalpy and entropy of activation have been calculated using the dielectric data. Thermodynamic parameters indicate existence of cooperative orientation in the molecule resulting from the dipole interaction.

3 table, 20 ref

017982   Sundaresan N K;Ambirajan A;Ranasamy A;Gupta P P;Bhandari D R (Thermal Systems Group, ISRO Satellite Centre, Bangalore-360 017) : Evaluation of thermal conductivity of ablative material. Indian J pure appl Phys 2006, 44(10), 719-23.

Ablatives are very often used in the Thermal Protection System of re-entry spacecraft. Their thermal conductivity will play an important role in determining the temperatures of components and pay loads during the on-orbit and re-entry phases on the mission. A series of calorimetric tests were conducted on these materials to ascertain their thermal conductivity. A description of the experiments and the results of analyses of the experimental temperature data from the ablatives are presented in this paper. Three-dimensional mathematical model of the experiment was developed and analysed. The thermal conductivity of two ablative samples is determined by manually minimising the root sum of squares error (RSSE) between experimental and numerical data. The results obtained using this technique are compared with the results of a one-dimensional analysis.

6 illus, 2 tables, 12 ref

017981   Soorya T N;Gupta S;Anand Kumar;Jain S;Arora V P; (Phyics Dep, Vardhaman College, Bijnor, Uttar Pradesh) : Temperature dependent optical property studies of nematic mixtures. Indian J pure appl Phys 2006, 44(7), 524-31.

The refractive indices n_e and n_o, of two nematic mixtures: ZLI 2141-000 and ZLI 2452 have been measured in the temperature range 291-391 K using 589 nm light source. A slight modification to the four-parameter model given m Li J et al., J Appl Phys, 96 (2004) 19, is made to carry out the analysis of the data. The temperature dependence of refractive indices and the birefringence agree closely with that obtained using four-parameter model. Different parameters have been compared. The value of parameter β is larger for ZLI 2452 than for ZLI 2141-000, which may be due to the presence of BCH in place of CB component in the latter. A linear relation is observed between birefringence (Δn) and the order parameter (S). The normalized polarizabilities: α_e/<60>α<62>, α_o/<60>α<62> and the order parameter S agree fairly well with those obtained using modified model.

6 illus, 1 table, 12 ref

017980   Shrivastava K;Duraphe S (Mathematics Dep, S.N.G.G.P.G. Coll, Bhopal) : Order of elements in a topological space. Ultra Scient phys Sci 2006, 18(2), 191-4.

Defines order of elements in a topological space. Several results concerning various properties of order of elements, are established.

5 ref

017979   Sharma S K;Dolia S N;Ravi Kumar R;Knobel M; Kumar V V S;Singh M (Physics Dep, H.P. Univ, Shimla-171 005) : Magnetic study of nanoparticles of Mg_0.95Mn_0.05Fe₂O₄ spinel ferrite. Indian J pure appl Phys 2006, 44(10), 771-3.

Magnetization of nanoparticles of Mg-Mn ferrite, synthesized using high energy ball milling has been studied. X-ray diffraction pattern of the particles milled for 6 h confirmed the single-phase cubic spinel structure with a lattice parameter of 8.47 A. Langevin function fitting on M-H data at 300K gives a log-normal particle size distribution with median diameter of 6.4 nm and standard deviation 0.7. The isothermal dc magnetization studies have been performed using SQUID and vibrating sample magnetometer in the temperature range 5-300 K. These measurements show that the sample is superparamagnetic above the blocking temperature T_B <126> 246 K. The reduction in saturation magnetization in the case of nanoparticles has been explained on the basis that the magnetic moments in the surface layers outside the core are in a state of frozen disorder.

4 illus, 12 ref

017978   Sharma A K;Kaura S K;Chhachhia D P;Mahajan C G;Aggarwal A K (Coherent Optics Div, Central Scientific Instruments Organisation, Sector 30, Chandigarh-160 030) : Holographic optics based two-channel interferometer. Indian J pure appl Phys 2006, 44(7), 501-8.

Describes a simple and cost effective method for making a two-channel interferometer based on holographic optics, which is suitable for performing optical test studies on two different phase objects simultaneously and independently. The optical arrangement in the proposed method involves a simple alignment procedure and inexpensive recording material is used in the formation of holographic optical elements. Recording schemes for the formation of holographic optical elements and the related techniques for the realization of the proposed interferometer along with the effect of misalignment of holographic optical elements and typical experimental results are presented.

7 illus, 13 ref

017977   Sawant R R;Bhosale C H (Electrochemical Materials Laboratory, Physics Dep, Shivaji Univ, Kolhapur-416 004) : Effect of sunstrate temperature on properties of spray deposited semiconducting CdIn₂S4 thin films. Indian J pure appl Phys 2006, 44(10), 741-5.

Spray pyrolysis is one of the most convenient, economical, inexpensive and simple methods for depositing large area semiconducting thin films. Semiconducting CdIn₂S₄ thin films have been deposited onto the amorphous and FTO coated glass substrates by varying substrate temperatures from 300, at the interval of 25 to 375°C. The optimized deposition temperature is around 350°C. The films have been characterized for their crystalline structure, photoelectrochemical (PEC) studies, energy dispersive analysis by X-rays (EDAX), optical and electrical transport properties by means of X-ray diffraction and thermoelectric power (TEP) measurement techniques. The cubic nature of CdIn₂S₄ thin films has been confirmed from XRD analysis. The PEC characterization shows that both short circuit current (I_sc) and open circuit voltage (V) are at their optimum values at the optimized substrate temperature of 350°C and solution concentration of 0.05M. EDAX studies show that the material formed at optimized preparative parameters is almost stoichiometric. The optical absorption study reveals that CdIn₂S₄ is indirect band gap material having band gap energy equal to 2.22 eV, matching with single crystal value. Semiconducting nature of the films is observed from the two-probe resistivity measurement. From TEP measurement, the material has been found to exhibit n-type conductivity.

8 illuse, 2 tables, 17 ref

017976   Saraswat V K;Singh K;Saxena N S (Semiconductor & Polymer Science Laboratory, 5-6, Vigyan Bhawan, University of Rajasthan, Jaipur-302 004) : Electrical measurements of Se_85-xTe₁₅Sb_x glasses. Indian J pure appl Phys 2006, 44(10), 782-5.

Temperature dependence of I-V characteristics and dc conductivity of Se_85-xTe₁₅Sb_x (where x = 2, 4, 6, 8 and 10) glasses in the form of thin pellets has been studied. The pellets have been prepared from the ingots of glasses in the powder form. It is quite evident from I-V characteristics that the glass containing 4 at wt % of Sb allow maximum current to pass through itself as compared to its other counterparts of the series. The linear relationship between In (I) and V^1/2 strongly suggests the type of conduction as the Poole-Frenkel. The deviation from ohmic behaviour at lower voltages towards the non-ohmic behaviour at higher voltages is due to the additional thermal effects at higher temperatures induced in the sample. The electrical conductivity of these samples for the above-mentioned compositions using their I-V characteristics has been determined. The variations of electrical conductivity with composition at all temperatures show that Se₈₁Te₁₅Sb₄ glass has the maximum conductivity. This variation is explained using the bonding between Se and Sb at different compositions. Hence, the composition Se₈₁Te₁₅Sb₄ is more chemically ordered and electrically conducting as compared to other members of the series.

3 illus, 19 ref

017975   Rama Krishna K;Sobha V V;Rami Reddy A (Mechanical Engng Dep, Narasaraopeta Engng Coll, Narasaraopeta-522 601) : Effect of magnetic field on mixed convection in porous medium. Ultra Scient phys Sci 2006, 18(2), 181-90.

Deals with the effects of magnetic field on mixed convective flow over a heated vertical flat plate embedded in a highly conducting fluid saturated porous medium. It is assumed that the wall temperature of the plate is a power function of the distance from the leading edge. Boundary layer approximations are invoked by considering a very large Rayleigh number. The ratio of Rayleigh number to Peclet number is considered to asses the forced, aiding mixed and opposed mixed convection effects on the plate. Further the effect of magnetic field on the boundary layer thickness and heat transfer characteristics is studied by introducing the Hartmann number. Results indicate that applied magnetic field will enhance the rate of heat transfer and is found more effective in aided mixed forced convection than in opposed mixed convection.

5 illus, 9 ref

017974   Rajabi A A (Physics Dep, Shahrood University of Technology, P O Box 36155-316 Shahrood, Islamic Republic of Iran, Email: A.A.rajabi@shahrood.ac.ir) : Determining the relation between effective coupling constant and quark mass in the parton model using massive nucleonic quarks in hypercentral potential. Indian J pure appl Phys 2006, 44(7), 512-18.

The reliable values of effective strong coupling constants (α_s) for hadrons from various reactions have been found by investigating experimentally. So far, it has been proved that the α_s is not a fixed quantity. It has been shown that how the value of α_s depends on the constituent quark masses in hadrons. The effective values of α_s for different quark masses can be determined by using short-range attractive hyper-Coulombic potential, which would be in agreement with In(q²lm²).

1 illus, 5 table, 24 ref

017973   Pujar S S;Bhati S M (S.R.E.S's Coll of Engng, Mathematics Dep, Kopargaon-423 603) : Conformality and isometry of Riemannian manifolds to spheres. Ultra Scient phys Sci 2006, 18(2), 195-206.

Considers the n-dimensional (n<62>2) compact and orientable Riemannian manifold M admittin a conformal transformation X in M satisfying (2,1), The main purpose is to obtain the integral formulas in Riemannian manifold and use them as powerful tool to describe the global results, Obtained some conditions in terms of integral formula for to be isometric to a sphere without putting restrictions on the scalar curvature of M. In section 4, it is shown that the results shall include the results ofYano and Sawaki^2,5 and some of those of Amur and Pujar³ as a special case,

27 ref

017972   Patidar D;Kumar S;Sharma R;Saxena N S;Sharma K;Sharma T P (Physics Dep, Semiconductor and Polymer Science Laboratory, 5-6, Vigyan Bhawan,) : Optical and structural properties of cds thick film. Indian J pure appl Phys 2006, 44(10), 729-31.

Cadmium sulphide film has been prepared in open-air atmosphere by sintering technique-using ZnCl₂ as an adhesive source and glycol as a binder. The reflection spectra of covered sintered film of CdS are recorded by a spectrophotometer- at room temperature in the wavelength range 300-700 nm. From reflection spectra, energy band gap has been determined. It is found that energy band gap of this film is 2.57 eV, which is the energy band gap of Cd_0.8Zn_0.2S. This is suggestive of the fact that Cd_0.8Zn_0.2S is a wide band gap semiconducting material. X-ray diffraction patterns also confirm the formation of Cd_0.8Zn_0.2S.

017971   Panicker C Y;Varghese H T;Philip D (Physics Dep, TKM College of Arts and Science, Kollam-691 005) : Surface enhanced Raman spectrum of 3-cyanopyridine. Int J chem Sci 2006, 4(1), 76-80.

FT-Raman spectra of 3-cyanopyridine has been recorded and analysed. Surface Enhanced Raman scattering (SERS) spectrum was recorded in a silver colloid. 3-cyanopyridine is thought to adsorb In a somewhat 'tilted side on orientation' with respect to the silver surface.

2 illus, 1 table, 15 ref

017970   Mukhopadhyay R;Mitra S (Solid State Physics Div, Bhabha Research Centre, Mumbai-400 085) : Molecular diffusion and confinement effect:neutron scattering study. Indian J pure appl Phys 2006, 44(10), 732-40.

Confined fluids generally have properties different from those of adsorbed layer or bulk phases. Diffusion, translational or rotational, is altered significantly on confinement. The molecular dynamics and its effect due to confinement in various environments as studied by Quasi-elastic Neutron Scattering (QENS) technique have been reported. QENS offers a unique possibility of analyzing spatial dimensions of atomic or molecular processes in their development over time. It is found that dynamics of a fluid confined in porous medium depending on the nature of the medium and interaction, can have a variety of modifications. The diffusivity of guest molecules embedded in zeolite or molecular sieves depends very much on the combination of the guest and host structures shape and specific interactions.

8 illus, 4 tables, 32 ref

017969   Mondal T;Sengupta D;Mandal A (Geology and Geophysics Dep, Indian Institute of Technology, Kharagpur-721 302, Email: dsgg@gg.iitkgp.ernet.in) : Natural radioactivity of ash and coal in major thermal power plants of West Bengal, India. Curr Sci 2006, 91(10), 1387-93.

Natural radioactivity due to the presence of ²³⁸U, ²³²Th and ⁴⁰K in ash and coal in major thermal power plants of West Bengal, namely Kolaghat, Durgapur and Bandel, has been measured by a NaI (TI)-based gamma ray spectrometer. The average activity concentrations of the radioelements ²³⁸U, ²³²Th and ⁴⁰K in the ashes of Kolaghat were found to be 111, 140 and 351 Bq/kg respectively, at Durgapur 97,107 and 315 Bq/kg respectively, and at Bandel 106, 126 and 321 Bq/kg respectively. The absorbed gamma doses in air due to naturally occurring radionuclides in the ash from the power plants varied from 123 to 150 nGy ^h-1, which are higher than three times the world average of about 43 nGy h^-1. The ash from power plants contains 2 to 3 times more natural radio nuclides than that in feed coal. Ash samples have radium equivalent activity (Raeq) and external hazards index (Hex) values closest to 370 Bq/kg and unity respectively, which have implications in terms of radiation hazard arising due to the use of these ash samples in building and construction.

2 illus, 5 tables, 19 ref

017968   Mehta R V;Desai R;Bhatt P;Upadhyay R V (Physics Dep, Bhavnagar Univ, Bhavnagar-364 002, Email: rvm@bhavuni.edu1) : Synthesis and characterization of certain nanomagnetic particles coated with citrate and dextran molecules. Indian J pure appl Phys 2006, 44(7), 537-42.

Nanomagnetic particles of magnetite and Mn-Zn ferrites are synthesized and coated with dextran and citrate molecules. Particles are characterized by XRD, FTIR , TGA and magnetometry. FTIR as well as TGA shows that binding of citrate molecules on magnetite is stronger then in case of dextran on magnetite. In the case of Mn-Zn ferrite particles citrate ions are bound by physi- as well as- chemi-absorption. The calculated value of binding from TGA analysis agrees with that obtained from magnetometry analysis.

9 illus, 1 table, 9 ref

017967   Kishore V;Sharma R;Saxena N S (Physics Dep, Semiconductor and polymer Science Loboratory, Rajasthan Univ, Jaipur-302 004) : Simultaneous measurement of thermal conductivity and diffusivity of Se₈₅Cd_15-xZn_x system at room temperature. Indian J pure appl Phys 2006, 44(10), 759-62.

The samples of selenium rich Se₈₅Cd_15-xZn_x (x= 0, 3, 7, 11 and 15) have been prepared by slow cooling of melt technique. The pellets of the samples have been prepared at constant load of 10 ton (pressure of 866 Mpa). Measurements of effective thermal conductivity (λ_c) and effective thermal diffusivity (χ_c) of selenium rich Ses5Cd_15-xZn_x pellets, have been carried out at room temperature using transient plane source (TPS) technique. From the measured values of λ_c and χ_c, specific heat per unit volume (C_p, derived quantity) of these samples in the composition range of investigation, have been determined. The variations of effective thermal conductivity and effective thermal diffusivity of Se₈₅Cd_15-xZn_x with composition have been explained on the basis of binding energy of the alloys formed and mean free path of the phonons.

6 illus, 10 ref

017966   Joshi G P;Saxena N S;Sharma T P;Mishra S C K (Condensed Matter Physics Laboratory, Physics Dep, Univ of Rajasthan, Jaipur-302 004) : Measurement of thermal transport and optical properties of conducting polyaniline. Indian J pure appl Phys 2006, 44(10), 786-90.

Measurements of effective thermal conductivity (λ_c) and effective thermal diffusivity (χ_c) of twin pellets of conducting polyaniline, prepared under a load of 5 ton were carried out from room temperature to 170°C at normal pressure using transient plane source (TPS) technique. The values of λ_c and χ_c by the use of an empirical relation at various fixed temperature in the above mentioned range have been calculated. The calculated values are in good agreement with the experimental results over the entire range of temperatures of investigation. Besides, the optical band gap of the sample is determined using reflection spectra in the wavelength region 300-800 nm. From the analysis of reflection spectra, polyaniline is found to have energy band gap 3.1 eV. The results indicate that band gap values are dependent on annealing temperatures of the samples and λ_c and χ_c vary with annealing temperature in the range from room temperature to 170°C. The effective thermal conductivity and effective thermal diffusivity are maximum at about 100°C, whereas the optical band gap is minimum for the sample annealed at 100°C as compared to other annealing temperatures.

7 illus, 10 ref

017965   Jain N;Patidar D;Saxena N S;Sharma K (Physic Dep, Semiconductor and Polymer Science Laboratory, Rajasthan Univ, 5 6, Vigyan Bhawan, Jaipur) : Temperature dependence of dc conductivity in polyaniline-metal halide composite. Indian J pure appl Phys 2006, 44(10), 767-70.

Polyaniline (PANI) and its metal halide composites of trivalent metal ions of Ni and Co have been synthesized with various compositions (0, 50, 100 M%) by chemical oxidative polymerization technique with ammonium peroxydisulphate in aqueous hydrochloric acid medium. I-V characteristics of these materials at room temperature as well as function of temperature (313-393K) have been studied. The temperature and composition dependence of dc conductivity for these materials has been investigated. The dependence of conductivity on temperature is suggestive of the metallic nature of the composites and shows positive temperature coefficient of resistance. The variation of electrical conductivity in the composition shows the lowest conductivity for Co-Ni (50-50) over the values obtained for Ni (100) and Co (100) separately. This interesting result can be explained on the basis of bonding of cobalt and nickel with polyaniline matrix during their polymerization.

6 illus, 11 ref

017964   Jai Prakash;Singh P K;Dwivedi D K (Physics Dep, D D U Gorakhpur Univ, Gorakhpur-237 009) : Thermally stimulated processes: I-mechanisms involved in the appearance of a thermoluminescence glow curve. Indian J pure appl Phys 2006, 44(7), 532-6.

Mechanisms involved in the appearance of a thermoluminescence (TL) glow curve are re-investigated with an aim to establish a suitable model. A generalized equation has been developed which is found to be able to explain the intensity of TL glow curves of different systems. Suggested equation successfully represents the TL intensities of systems involving different order of kinetics including first order. The proposed model helps in the evaluation of the values of trap depth or activation energy, the frequency factor governing the release of electrons from their traps, the initial concentration of the trap centres, order of kinetics involved and extent of rates of retrapping and recombination.

2 illus, 18 ref

017963   Gunasekaran S;Natarajan R K;Renganayaki V; Natarajan S (Post Graduate and Research Department of physics, Pachaiyappa's College, Chennai-600 030, Email: renganayaki_sri@rediffmail.com) : Vibrational spectra and thermodynamic analysis of metformin. Indian J pure appl Phys 2006, 44(7), 495-500.

Metformin is one of the important anti-diabetic drugs to treat non-insulin dependent diabetes mellitus (NIDDM). Fourier transform infrared (FTIR) and Fourier transform Raman (FTR) spectra of metformin have been used for the molecular study. A satisfactory band assignment has been made on the fundamental modes of vibration. Employing the molecular mechanics method using MM3 force field, the theoretical vibrational frequencies and geometry parameters like bond lengths, bond angles etc are calculated and compared with the experimental frequencies. The observed frequencies are used to compute the thermodynamic functions, namely, the enthalpy, entropy, heats of formation, heat capacity using standard expressions at temperature 298 K and one atmospheric pressure.

4 ref

017962   Goyal P S;Aswal V K (UGC-DAE CSR, Mumbai Centre, Bhabha Atomic Research Centre, Mumbai-400 085) : Combined SANS and SAXS in studies of nanoparticles with core-shell structure. Indian J pure appl Phys 2006, 44(10), 724-8.

Small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) are essentially diffraction experiments involving small (<126>1°) scattering angles. Unlike conventional diffraction experiments (XRD or neutron diffraction) where one examines the specimen with an atomic resolution (<126>0.2 nm), SANS/SAXS are used to investigate structures on a length scale of <126>10 nm. Hence, SANS/SAXS are ideal techniques for studying the sizes and shapes of nanoparticles. At times, because of differences in contrast for neutrons and X-rays, a combined SANS and SAXS study provides information about the core and the shell structure of nanoparticles. This paper gives an introduction to the techniques of SANS and SAXS and their applications in material science. Recent results on study of core-shell structure of a micelle (nanoparticle of organic material) are presented.

3 illus, 13 ref

017961   Gaur M S;Gaur K;Khare P K;Singh R (Physics Dep, Hindustan College of Science & Technology, Farah (Mathura), U P-281 122) : Effect of annealing time on thermally stimulated current in kindey stone samples. Indian J pure appl Phys 2006, 44(10), 751-3.

An electret is a dielectric material which retains the polarization produced in it for a longer time and produces the electrostatic field without any source of voltage. The biomaterials like collagen, DNA, RNA and blood vessel walls etc possess this property. The kidney stone mainly consists of calcium oxalate and calcium phosphate, which are dipolar in nature. The pellet of the powdered kidney stone was formed in a mica window and identical aluminium electrodes were prepared. The thermal polarization was carried out by sandwiching the sample between aluminium electrodes in electrode assembly, which was kept in digital controlled oven. The observed behaviour of thermally stimulated current (TSC) peak is found to be strongly dependent on annealing time, which shows the presence of shallow and deeper traps in material. These traps are probably formed during the crystallization of substance in kidney.

017960   Dolia S N;Sharma R;Sharma M P;Saxena N S (Physics, University of Rajasthan, Jaipur-302 004) : Synthesis, x-ray diffraction and optical band gap study of nanoparticles of NiFe₂O₄. Indian J pure appl Phys 2006, 44(10), 774-6.

Nanoparticles of NiFe₂O₄ have been synthesized by chemical co-precipitation method. X-ray diffraction pattern confirms the formation of single-phase cubic spinel structure and the lattice constant is 8.2 A. The energy band gap measurements of nanoparticles of Ni ferrite in pellet form have been carried out by reflection spectra using double beam spectrophotometer. A pellet of nanoparticle ferrite was made under a load of 10 tons. From the analysis of reflection spectra, nanocrystalline Ni ferrite have been found to have energy band gap of 2.5 eV at room temperature.

3 illus, 20 ref

017959   De S S;Ghosh A K;Ghosh T K;Jana D (Center for Advanced Study in Radiophysics and Electronics, Calcutta Univ, Kolkata-700 009) : Effective heating in heavilly doped semiconductor devices. Indian J pure appl Phys 2006, 44(7), 543-7.

A model has been developed to investigate the heat generation processes in semiconductor devices under heavily doped condition. The equilibrium between heat generation and heat dissipation by various mechanisms has been studied. The variations of heat dissipation with the change of carrier concentrations and the heat along the distance from the junction to the bulk have been estimated by numerical analyses. These are shown graphically with the results of an earlier work.

2 illus, 19 ref

017958   Das M;Prasad R;Sen P (Physics Dep, S G S Institute of Technology & Science, Indore-452 003, Email: pratima_sen@hotmail.com) : Structure analysis and second-order non-linear optical activity of urea hydrogen peroxide adduct. Indian J pure appl Phys 2006, 44(7), 554-8.

Urea hydrogen peroxide adduct is synthesized and characterized using UV and IR spectra. Second harmonic generation (SHG) efficiency has been determined experimentally in this adduct using pulsed Nd: YAG laser at 1064 nm wavelength. The efficiency is higher in the adduct as compared to urea. Geometry of the molecule was optimized using Austin Model 1 (AM1) semi-empirical technique. Computations suggest two conformers of the adduct, both having no center of symmetry. Complete geometry of the molecule and the dipole moment calculations have been reported. It is concluded that increased dipole moment of one of the conformers of the adduct is responsible for the enhanced SHG efficiency of the adduct.

4 illus, 1 table, 10 ref

017957   Chauhan A R;Mahadkar A;Gaikwad d;Patel A P (N G Acharya & D K Marathe College of Arts, Science and Commerce, Chembur, Mumbai-400 071) : Structural studies of synthesis of CdSe from Cd/Se bilayer. Indian J pure appl Phys 2006, 44(10), 777-8.

Cadmium and selenium bilayer have successfully been made by a vacuum evaporation technique on cleaned glass substrates under the vacuum of the order of 10^-5mbar. The samples of different thicknesses were prepared by varying Cd:Se ratio as 1:1, 1:1.5,1:2. Rapid thermal annealing (RTA) of some bilayers have been carried out at different temperatures in nitrogen ambient. XRD measurements were made for structural analysis on these as-deposited and annealed samples. RTA studies could show the formation of cadmium selenide at the interface after annealing. XRF measurements were carried out for elemental analysis of these bilayers. XRF studies reveal that the films are found to be cadmium rich at room temperature. The results of CdSe formed from Cd/Se bilayer by RTA are compared with annealed sample.

2 illus, 2 tables, 10 ref

017956   Chandok R S;Kaur R;Chandok G K;Chandra B P (Sri Guru Tegh Bahadur Khalsa College, Mahanadda, Jabalpur) : Temperature effect on lyoluminescence of potassium halide microcrystals in luminol solution. Indian J pure appl Phys 2006, 44(7), 519-23.

When γ-irradiated microcrystals of potassium halides are dissolved in the luminol solution, the lyoluminescence (LL) intensity initially increases linearly with time, attains an optimum value and then decreases and finally disappears. The LL intensity was detected by PMT whose output was connected to X-Y recorder. Temperature dependence of LL intensity shows that initially the peak of LL intensity (I_m) increases with temperature, attains a peak value, and then decreases with further increase in temperature. Also, the total intensity I_T initially increases, attains an optimum value and then it decreases with further increase in temperature. The decay time decreases with increasing temperature of the solvent, from where the value of activation energy E_a can be calculated. A plausible explanation for the experimental results is given.

ref

017955   Barua A G;Borah A K;Jois S S (Physics Dep, Gauhati Univ, Guwahati-781 014) : Interaction of dye laser beam of wavelength 5750 Anstrong with absorption lines of nitrogen. Indian J pure appl Phys 2006, 44(7), 509-11.

The quasi-random model of molecular band absorption is used to study the interaction of dye laser beam of wavelength 5750 Anstrong with the absorption lines of nitrogen. The values of transmittance, averaged over intervals of 0.2 cm^-1, are obtained for two different path lengths in the frequency range 17386 - 17397 cm^-1. From these values, the intensities of the absorption lines in the first positive system of N₂ have been simulated.

2 illus, 10 ref

017954   Agarwal R;Saxena N S;Sharma K B;Thomas A; Pothan L A (Physics Dep, Government College, Ajmer) : Thermal conduction and diffusion through polyester composites. Indian J pure appl Phys 2006, 44(10), 746-50.

Using Transient Plane Source technique, thermal properties like thermal conductivity, thermal diffusivity and specific heat of polyester composites of banana fibers (treated and untreated) are measured simultaneously at room temperature and normal pressure. The increase in thermal conductivity is observed in some treatments. The performance of the composite depends to a large extent on the adhesion between polymer matrix and the reinforcement. This is often achieved by surface modification of the matrix or the filler. Banana fiber was modified chemically to achieve improved interfacial interaction between the fiber and the polyester matrix. Various silanes and alkali were used to modify the fiber surface. Chemical modification was found to have a profound effect on the fiber/matrix interaction which is evident from the enhanced thermal conductivity values. Of the various chemical treatments, simple alkali treatment with 1% NaOH was found to be the most effective.

1 table, 17 ref

016970   Yi S W;Jung M H (Phys Dep, KAIST, Daejon-305 701, Korea) : Dielectric response of antiferroelectric liquid crystal CS-4001. Asian J Phys 2005, 14(3-4), 301-8.

9 illus, 6 ref

016969   Verma P K;Srivastava R;Khanna K N (Physics Dep, V.S.S.D. College, Kanpur-208 026) : Specific heat of linear tangent hard sphere chains. Indian J Phys 2006, 80(8), 837-9.

The specific heat (C_p) of linear tangent hard sphere chains of varying length is determined by employing Wertheim's first order perturbation theory. It is shown that the equation of state obtained by Wertheim's first order perturbation theory predicts the same values of specific heat as those obtained through the equation of state obtained by Monte Carlo computer simulation.

1 table, 21 ref

016968   Rim M H;Lee K (Physics Dep, Inha Univ, Incheon-402 751, Korea) : Doppler effect of de broglie waves. Asian J Phys 2005, 14(3-4), 247-50.

Relativistic nature of the de Broglie wavelength formula in Doppler effect is discussed. Doppler effect of de Broglie waves has been considered using the relativistic expression of velocity addition formula. It is shown that when relative speed of the particle and the observer is close to the relativistic limit, the derived expression for matter wave Doppler effect converges to the light wave Doppler effect. In the nonrelativistic limit, the matter wave Doppler effect formula converges to the sound wave Doppler effect formula for the case of the observer approaching the source.

3 ref

016967   Raychaudhuri A (Theoretical Physics Dep, Indian Association for the Cultivation of Science, Jadavpur, Calcutta) : Relativistic cosmoloy. Indian J Phys 2006, 80(9), 943-6.

016966   Raychaudhari A (Physics Lab, Asutosh College, Calcutta) : Arbitrary concentrations of matter and Schwarzschild singularity. Indian J Phys 2006, 80(9), 937-41.

A nonstatic solution of the Einstein gravitational equations representing a spherically symmetric cluster of radially moving particles in an otherwise empty space is obtained. While it has been presumed by Einstein that the Schwarzschild singularity is physically unattainable as matter cannot be concentrated arbitrarily, the present solution seems to show that there is no theoretica1 limit to the degree of concentration, and that the Schwarzschild singularity has no physical reality as it occurs only in some particular coordinate systems. Incidentally, it is shown that in case of spherical symmetry, the condition of conservation of gravitational energy of an isolated system of fluid material is equivalent to the vanishing of pressure at the boundary.

016965   Rashdan M;Farhan A M;Hassib E;Abdel Kareem W (Mathematics and Theoretical physics Dep, Atomic Energy Authority, Cairo, Egypt) : Isopin dependence of the nucleus - nucleus inelastic cross section at high energy. Indian J Phys 2006, 80(8), 815-18.

The isospin dependence of the nucleus - nucleus inelastic cross section at high energy is investigated within the multiple scattering theory. The multiple integrals are evaluated by Monte Carlo method as well as by the optical limit approximation of the Glauber model. Calculations are performed for ^14-23N, ^16-24O and ^18-26F isotopes colliding with carbon target around 1 GeV. It is found that rms radii and the density distributions show a halo structure of ²²N, ²³O and ²⁴F.

3 illus, 1 table, 12 ref

016964   Rajkhowa M;Das M K;Nimai Singh N (Physics Dep, Gauhati University, Guwahati-781 014) : Possible radiative origin of Δm<. Indian J Phys 2006, 80(8), 829-35.

Readdresses the issue on the possible origin of Δm²₂₁ and sin θ₁₃ from radiative corrections first discussed in Ref. [Phys. Rev'. D67 091302 (2003)]. The authors show here the possibility for generating both low-energy values of Δ²₂₁ and sin θ₁₃ through radiative corrections in the minimal supersymmetric standard model (MSSM), provided two of the neutrino mass eigenvalues having opposite CP parity, are assumed to be degenerate at high energy scale, viz., m_i = (m, -m, m') where m' is non-zero. Simultaneous running of the three neutrino mass eigenvalues and three .mixing angles in the ROEs, is carried out. The input values of the initial conditions, Δm²₂₁ = 0 and sin θ₁₃ = 0 at high energy scale M_R =1.6 x 10¹⁶r GeV, for large value of tan β = 60 give sizable radiative corrections leading to low-energy values of Δ²₂₁ = 8.6 x 10^-5 eV² and sin θ_1.3 = - 0.226. These results are new and almost consistent with the LMA MSW solution on the solar neutrino problem.

2 illus, 2 tables, 22 ref