017984   Kumar S;Verma A S;Bhardwaj S R;Sharma D (Physics Dep, B S A College, Mathura-281 004) : Mechanical property of rare aarth monochalcogenides. Acta Cienc Indica-Phys 2009, 35(4), 643-6.

The value of bulk modulus of any material is a mechanical property, which is an important physical quantity. Previous researchers have shown that the bulk modulus of the solid- state compounds is correlated with the cell volume. We have investigated an empirical relationship between the bulk modulus of rare earth monochalcogenides and average atomic number of constituent atoms (_AB). The modified relation has been evolved in terms of atomic number of cation (Z_A) , atomic number of anion (Z_B) and average atomic number of constituent atoms (Z_AB). We have applied the proposed relation on a wide range of compounds and found a better agreement with experimental data as compared to the values evaluated by earlier researchers.

1 illus, 1 table, 18 ref

017983   Kumar S;Sharma D;Verma A S;Bhardwaj S R (Physics Dep, B S A College, Mathura, (India) 281 004) : Linear relationship between the effective charge and crystal ionicity of molybdenum (Mo) dichalcogenides. Acta Cienc Indica-Phys 2009, 35(4), 639-42.

Presented a linear relationship between the values of effective charge (q) and crystal ionicity (f_i) of molybdenum (Mo) dichalcogenides. In this paper, we have also investigated various electronic properties viz. homopolar energy gaps (E_h), heteropolar energy gaps (E_c), average energy gaps (E_g) , Penn gaps (E_p) and crystal ionicity (_i;) of molybdenum (Mo) dichalcogenides using the Phillips and Van Vecten (PVV) theory.

1 table, 18 ref

017982   Jha B K;Mahto D;Prasad U;Chandra G (University Dep of Physics, L N M U, Darbhanga) : Electromagnetic properties of rotating media on the basis of electron-theoretical study. Acta Cienc Indica-Phys 2009, 35(4), 717-28.

Minkowski discussed the electromagnetics of moving media using special theory of relativity. Later W. Pauli and A. Sommerfeld tried to extend Minkowski's theory to accelerated frame, but it was found to depend on Minkowski's theory. C.V. Heer and T.C. Moller extended Minkowski's idea to accelerated frame using tensor calculus C.T. Tai developed the electromagnetics of moving media in an accelerated frame in three dimensional system with one using tensor calculus with the help of electron-theoretical view points. We have discussed the electromagnetic field equations when observer or material media are rotating with respect to inertial frame. We have also investigated the electromagnetic aspects produced by the inertial forces like centrifugal and Coriolis forces appearing in the rotational motion.

1 illus, 10 ref

017981   Dubey N (Physics Dep, Prist University, Thanjavur, Tamil Nadu) : Dual coupled resonator local oscillator and its application. Acta Cienc Indica-Phys 2009, 35(4), 699-709.

Describes how two coupled resonators, thus forming a second order coupled network can be used to produce an oscillator with a lower phase noise than can be obtained using a single resonator. The design technique is illustrated using a typical MMIC and Microstripline resonators. Microwave Office computer simulation shows a 2.8 dB improvement in phase noise. The constructed oscillator oscillated close to the design frequency and produced a lower phase noise than a single resonator oscillator using the active same devices.

14 illus, 2 tables, 9 ref

017980   Dubey N (Physics Dep, Prist University Thanjavur, Tamil Nadu) : Realization of low-cost doppler speed-over-ground sensor with fundamental-frequency PH EMT-DRP. Acta Cienc Indica-Phys 2009, 35(4), 691-7.

A 24 GHz high-performance Doppler sensor for non- contact measurement of vehicle speed and position is reported. The compact dimensions and the economical design make the sensor ideally suited for automotive applications. A special feature is the 24 GHz fundamental-frequency dielectric resonator oscillator employing a low-cost packaged-aged HEMT. An excellent phase-noise behavior and good temperature stability are achieved due to higher-order mode operation of the dielectric resonator, The new Doppler sensor provides high reliability and gives excellent measurement results in both car and train tests.

9 illus, 1 table, 10 ref

017979   Bakkialakshmi S;Shanthi B (Physics Dep, AnnamalaiUniversity, Annamalainagar-608 002) : Fluorescence quenching of biphenyl and ethylmethyl ketone. Acta Cienc Indica-Phys 2009, 35(4), 669-77.

The study of fluorescence quenching of Biphenyl by Naphthalene & Phenolphthalein and ethyl methyl ketone by cinnamaldehyde & azabenzene in two different solvents gives the valuable information and these are presented in this paper. Stern-Volmer plots for the quenching of the Biphenyl by Naphthalene, & Phenolphthalein and ethyl methyl ketone by cinnamaldehyde & azabenzene in two different solvents are also drawn. The Stern-Volmer constants and regression coefficients are calculated for each and are given in the corresponding figures. Stroke's shift, ionization potential, electron affinity, molar extinction coefficient and the solvent parameter (z) are calculated and are presented in this paper. It is confirmed that, the type of quenching here is dynamic quenching.

12 illus, 3 tables, 10 ref

017978   Bahan E;Prasad R S (NO, , 306-B, Laxmi Apartment, Chitragupta Nagar, Kankarbagh, Patna-800 020) : Charge distribution and dipole moments of tetraazatetrahedrane (N₄) isomers. Acta Cienc Indica-Phys 2009, 35(4), 655-7.

By use of an approximate Self-Consistent Field (SCF) method MRINDO/S, the potential nitrogen molecules, tetraazatetrahedrane (N₄4) isomers were studied. The N₄isomers considered in the present study belong to the molecular point groups T_d, D_2h and C_h respectively. We report charge distribution and dipole moments of the isomers. The charge distribution was accounted for by making use of Mulliken population analysis. This makes easy to calculate their dipole moments.

1 illus, 3 ref

017977   Bahan E;Prasad R S (NO, , 306-B, Laxmi Apartment, Chitragupta Nagar, Kankarbagh, Patna-800 020) : Electronic spectra of tetraazatetrahedrane (N₄) isomers. Acta Cienc Indica-Phys 2009, 35(4), 647-53.

By use of an approximate Self-Consistent Field (SCF) method MRINDO/S, the potential nitrogen molecules, tetraazatetrahedrane (N₄) isomers were studied. The N₄ isomers considered in the present study belong to the molecular point groups T_{dD>,D2h and Cs respectively. We report their ionization potentials, singlet and triplet excitations and singlet-triplet splittings. The Rydberg excitations pertaining to the spectra of the isomers are also reported.}

3 tables, 14 ref

017976   Amitabh Kumar;Vats S P;Tiwari B K;Arun Kumar (Electronics Dep, A N College, Patna-800 013) : Effect of temperature on the dynamic performances of a mosfet-bjt composite unit (M-MOS-N). Acta Cienc Indica-Phys 2009, 35(4), 567-73.

A new unipolar-bipolar Composite unit comprising of a MOSFET and BJT has been devised [1]. The Transconductance and Drain resistance of M-MOS-N show remarkable improvements over MOSFET [2]. This article reports the thermal effect on MOSFET parameters. Transconductance of M-MOS-N shows very small temperature drift as compared to MOSFET. Also, there is a little variation in the drain resistance of M-MOS-N with temperature, rendering it more or less indifferent to temperature variations in the active region of the device.

5 illus, 3 ref

017975   Adarsha Kumar (Physics Dep, L C S College, Darbhanga (Bihar)) : Electromagnetic scattering from complex penetrable bodies. Acta Cienc Indica-Phys 2009, 35(4), 635-8.

High-order integral algorithm for the solution of scattering problems by heterogeneous bodies under TE radiation has 0 been presented. Here, a scatterer is represented by a varying refractive index n(x) within a two-dimensional (2-D) bounded region; solutions of the associated Helmholtz equation under given incident fields are then obtained by high-order inversion of the Lippmann- Schwinger integral equation. The algorithm runs in O(N log (N)) operations, where N is the number of discretization points. Our method provides highly accurate solution in short computing times, even for problems in which the scattering bodies contain complex geometric singularities. The performance of the present algorithm in general cases improves by many orders of magnitude over that exhibited by other methods.

1 illus, 1 table, 4 ref

017054   Xavier R J;Balachandran V;Arivazhagan M; Ilango G (Physics Dep, H H The Rajah's College, Pudukkottai-622 001, Email: rj_xavier@yahoo.com) : Vibrational spectra analysis of 1-methoxynaphthalene. Indian J pure appl Phys 2010, 48(4), 245-50.

The solid phase FTIR and FT-Raman spectra of 1-methoxynaphthalene (MN) have been recorded in the regions 4000-50 and 3500-100 cm^-1, respectively. The spectra have been carried out for the molecule of the title compound using the fundamental modes of vibration observed in infrared and Raman spectroscopy and interpreted with the aid of normal coordinate analysis (NCA). The vibrational modes are classified into A' and A" irreducible representations and distributed as Γ_vib = 41 A' (in-plane) + 19A" (out-of-plane) based on C_s point group symmetry associated with the structure. A systematic set of symmetry coordinates has been constructed. Wilson's F-G matrix method has been adopted for the normal coordinate analysis. A reasonable set of potential constants evaluated for this molecule has been compared with those of related molecules and are in the characteristic range. The potential energy distribution (FED) has been evaluated using the vibrational spectral data and molecular parameters. A satisfactory vibrational band assignment has been made by using the FTIR and FT Raman spectra of the compound.

3 illus, 3 tables, 20 ref

017053   Virendra Kumar;Panikar Y;Palafox M A;Vats J K;Kostova I;Lang K;Rastogi V K (Physics Dep, C C S Univ, Meerut-250 004, Email: v_krastogi@rediffmail.com) : Ab-initio calculations, FT-IR and FT-Raman spectra of 2-chloro-6-methyl benzonitrile. Indian J pure appl Phys 2010, 48(2), 85-94.

FT-IR spectrum of 2-chloro-6-methyl benzonitrile in the region 400-4000 cm^{-1 has been recorded in KBr pellet technique with a Bruker IFS-66 Fourier transform spectrometer. FT-Raman spectrum in powder form has been recorded in the region 50-4000 cm-1 on a Bruker IFS 66 optical bench with an FRA 106 Raman module attachment interfaced to a microcomputer. Geometry and vibrational wavenumbers were calculated using ab-initio calculations with HF method. The results were compared with experimental values. The observed FT-IR and FT-Raman vibrational frequencies were analyzed and assigned to different normal modes of the molecule. Most of the modes have wavenumbers in the expected range and the error obtained was, in general, very low. Using PEDs, the contributions were determined for different modes to each wavenumber. From the FED, it is apparent that the frequency corresponding to C≡N stretching contains 88% contribution from the C≡N stretching force constant and it mixes with C-CN stretching mode to the extent of 12%.}

5 illus, 2 tables, 66 ref

017052   Venkata Kiran Kumar R;Srinivas A;Bala Krishna Murthy V;Murali Mohan Rao K;Sambasiva Rao G (Mechanical Engg. Dep, P.V.P. Siddhartha Institute of Technology, Vijayawada, Andhra Pradesh, Email: vbkm64@rediffmail.com) : Static analysis of angle-ply laminates subjected to in-plane biaxial and out-of-plane transverse loads. Int J theor appl mech 2008, 3(2-3), 115-21.

Several factors such as mismatch of Poisson's ratios and mismatch of coefficients of thermal expansion at the interface of two layers with different fiber angles, and coupling between shear, extension and bending due to unsymmetrical stacking of layers in generally orthotropic laminates influence the response of the laminated fiber reinforced composite structures subjected to complex state of loading. As there are several factors influencing the stresses, it is extremely difficult to estimate the exact reason for the variation of stresses unless the effect of each factor is known separately. In the present analysis an attempt is made to study the effect of fiber angle, which causes coupling between bending, shear and extensional deformations, on the behavior of an angle-ply laminated composite plate subjected to in-plane biaxial and out-of-plane transverse pressure loading. A finite element method which works on the basis of three-dimensional theory of elasticity is employed to evaluate the deflections, in-plane, out-of-plane and interlaminar stresses. The finite element software ANSYS 11.0 has been successfully executed for the validation of the finite element models. The results obtained by varying the fiber angle are discussed. Investigative studies reveal that the stresses increase up to certain value of 9 and later decrease in case of in-plane biaxial loading due to the internal resistance developed at the interfaces of the layers with + 0 and -0 fiber angles. The main reason for the internal resistance is due to the restriction of free longitudinal, transverse and in-plane shear deformations that produce due to the coupling effect. In case of out-of-plane transverse loading, σ_x and τ_zx decrease, and σ_y and τ_yz increase with fiber angle. This is mainly due to the change in internal resistance in the laminate with change in fiber angle. This analysis is very much useful in studying the effect of fiber angle alone on the static response of the composite structures subjected to in-plane biaxial and out-of-plane transverse pressure loading.

5 illus, 2 tables, 7 ref

017051   Tripathi B;Sircar R;Srivastava D P;Gupta S; Trivedi J (NO, Institute of Solar Energy Gandhinagar, Pandit Deendayal) : Effect of inserting quantum wells on electrical parameters of microcrystalline-silison photovoltaic cell. Int J pure appl Phys 2009, 5(1), 33-40.

The effect of inserting hydrogenated microcrystalline-silicon (μc-Si:H) quantum well layers with Raman crystallinity of 0.07, in the intrinsic region of a p-i-n configuration of thin film μc-Si:H photovoltaic cell with a Raman crystallinity of 0.01, is investigated with the help of theoretical modeling. The dependence of open-circuit voltage, short-circuit current density, fill factor, and conversion efficiency over the band offset of well and barrier layers is studied. Partial correlation of the study with experimental results is established. This work provides an exclusive method to enhance the efficiency and FF of μc-Si:H silicon photovoltaic cell. The efficiency could be increased by nearly 10% of the efficiency value of μc-Si:H photovoltaic cell without quantum wells.

7 illus, 15 ref

017050   Thomas M;George K C (Physics Dep, B C M College, Kottayam-686 001, Email: marykutythomas@yahoo.co.in) : Characterisation and magnetic properties of nanocrystalline FePO₄. Indian J pure appl Phys 2010, 48(2), 104-9.

Nanocrystalline FePO₄ prepared by chemical method has been characterized using TG/DTA, XRD, TEM and FTIR. Magnetic studies have been carried out using VSM, SQUID magnetometry and ESR measurements. The FePO₄ for three reactant concentrations (1ML^-1, 0.1ML^-1, 0.02M L^-1) has been prepared and the effect of reactant concentration on particle size and hence, on magnetic properties is studied. Magnetic susceptibility and ESR measurements support each other and FePO₄ is found to be an anisotropic antiferromagnet with a Neel temperature of 21 K. As particle size decreases, the magnetic moment at room temperature decreases indicating magnetic moment disorder on the surface of smaller particles.

9 illus, 27 ref

017049   Srinivas A;Venkata Kiran Kumar R;Bala Krishna Murthy V;Murali Mohan Rao K;Sambasiva Rao G (Mechanical Engg Dep, P.V.P. Siddhartha Institute of Technology, Vijayawada, Andhra Pradesh, Email: vbkm64@rediffmail.com) : Static analysis of angle-ply laminates subjected to longitudinal and in-plane transverse loads. Int J theor appl mech 2008, 3(2-3), 107-13.

Several factors such as mismatch of Poisson's ratios and mismatch of coefficients of thermal expansion at the interface of two layers with different fiber angles, and coupling between shear, extension and bending due to unsymmetrical stacking of layers in generally orthotropic laminates influence the response of the laminated fiber reinforced composite structures subjected to complex state of loading. As there are several factors influencing the stresses, it is extremely difficult to estimate the exact reason for the variation of stresses unless the effect of each factor is known separately. In the present analysis an attempt is made to study the effect of fiber angle, which causes coupling between shear and extensional deformations, on the behavior of an angle-ply laminated composite plate subjected to longitudinal and in-plane transverse pressure loading. A finite element method which works on the basis of three-dimensional theory of elasticity is employed to evaluate the deflections, in-plane, out-of-plane and interlaminar stresses. The finite element software ANSYS 11.0 has been successfully executed for the validation of the finite element models. The results obtained by varying the fiber angle are discussed. Investigative studies reveal that all the stresses increase up to certain value of fiber angle (6) followed by down trend. This is mainly due to the coupling between shear and extensional displacements. This analysis is very much useful in studying the effect of fiber angle alone on the static response of the composite structures subjected to longitudinal and in-plane transverse loads.

9 illus, 2 tables, 7 ref

017048   Soundara B;Robinson R G (Civil Engineering Dep, Indian Institute of Technology, Madras, Chennai, Email: soundra_iit@yahoo.co.in) : Stress history of desiccated expansive soil. Indian Geotech J 2009, 39(4), 387-98.

Stress history of soils, commonly expresses in terms of preconsolidation pressure or over consolidation ratio is one of the most important properties of soils. Among other causes, desiccation is one of the causes of preconsolidation. This paper addresses the preconsolidation pressure of a desiccated expansive soil that was subjected to repeated cycles of wetting and drying under controlled laboratory conditions. Identical samples were subjected to repeated cycles of wetting and drying under surcharge pressures of 6.25, 12.5, 25, 50, 100 and 200 kPa so as to simulate the overburden pressure due to depth in the field. The movements during wetting and drying were recorded and equilibrium band width was achieved after about five cycles. After reaching equilibrium, samples were unloaded to the seating pressure of 6.25 kPa and conventional consolidation tests were conducted so as to determine the preconsolidation pressure. The experimental results show that the preconsolidation pressure of desiccated expansive soil depends on the surcharge pressure. The overconsolidation margin, which is the difference between the preconsolidation pressure and the effective vertical stress, of desiccated expansive soil is found to be almost constant of about 100 kPa. This suggest that desiccation induced preconsolidation pressure is similar to that of overburden pressure in the field.

9 illus, 2 tables, 19 ref

017047   Solanki R G (Physics and Electronics Dep, Dr H S Gour Univ, Sagar, Email: gargrekha25@rediffmail.com) : Electrochemical growth and studies of CdZnTe thin films. Indian J pure appl Phys 2010, 48(2), 133-5.

The preparation, structural, compositional and optical studies of cadmium zinc telluride (CdZnTe) thin films have been investigated. The samples were prepared on CVD grown tin conductive oxide substrate by single step electrodeposition technique. The electrodeposition potential and ionic current ratios were investigated by linear sweep voltammetry (LSV). The structural studies (XRD) of films are seen to be with a preferential orientation along the (111) phase. Scanning electron microscopy was used to study the surface morphology and grain size determination. The composition of CdZnTe films was analyzed using energy dispersive analysis of X-rays (EDAX). The optical transmission spectra of CdZnTe films were obtained on a Shimadzu two beam UV-vis spectrophotometer and results are discussed.

6 illus, 18 ref

017046   Singh K K;Kar M;Das H L (Centre for Nanotechnology, Indian Institute of Technology, Guwahati-781 039, Email: kksphystmc@yahoo.com) : Effect of substrate temperature on photoconductivity in CdS thin films. Indian J pure appl Phys 2010, 48(2), 110-14.

Photo-electronic properties of CdS thin films (0.25μm thick) grown by thermal evaporation (TE) method on cleaned glass substrates held at different substrate temperatures (Ts) in the range 300-473K have been studied under different intensities of white light, bias voltages and ambient temperatures. The grain sizes are found to increase with Ts which enhanced the photosensitivity of the films. The photosensitivity of the films has been found to increase with light intensity, Ts and bias voltage. The evaluation of dark and photo-activation energies and mobility activation energies show double photo-activation processes. The activation energies and the mobility activation energies are observed to be decreasing with increasing Ts and ambient temperature, and reveal the presence of various discrete trap distributions at different trap depths.

7 illus, 2 tables, 20 ref

017045   Sharma S C;Ramakrishna Naidu N K;Lakshmanan T S;Mittal M C;Sinha P P;Vaidyan V K (Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Trivandrum-695 022, Email: sharma_sc@vssc.gov.in) : Tailoring of density in carbon foams. Indian J Engng Mater Sci 2009, 16(1), 56-60.

Cell-size of the sacrificial polymeric scaffolding and concentration of the impregnating phenolic resin are taken as two variables for tailoring density in the carbon foam. Effects of cell-size and resin-concentration on density of carbon foam arc studied under three categories: (i) individual effect of varying cell-size with fixed resin-concentration, (ii) individual effect of varying resin-concentration with fixed cell-size, and (iii) synergistic effect of varying cell-size and resin-concentration. For a fixed resin-concentration and particularly for lower concentration of 10%, density marks a small incremental effect with the reduction in cell-size. It increases from 0.041 to 0.055 g/cc for a cell-size of 30 PPI (pores per inch) and 80 PP1 respectively. For a fixed cell-size and particularly for lower cell-size of 80 PPI, density shows a large incremental effect with increase in resin-concentration. Density increases from 0.055 to 0.210 g/cc for a resin-concentration of 10% and 90% respectively. Under the combined effect of decreasing cell-size and increasing resin-concentration, density records a massive increase of 412.2% from initial combination of 30 PPI cell-size and 10% resin-concentration to last combination of 80 PPI cell-size and 90% resin-concentration.

10 illus, 1 table, 10 ref

017044   Sharma R;Upadhyaya G K;Thakrey M (School of Studies in Physics, Vikram Univ, Ujjain-456 010, Email: rakesh_sharma_ujn@yahoo.co.in) : Vortex formation in axion condensate and dynamics of dark matter. Int J pure appl Phys 2009, 5(2), 121-32.

Examines Dark Matter dynamics by analyzing its fluid properties of vortex formation. Our results show that kinetic energy of a spiral shape galaxy like Milkyway becomes constant at larger distances. It is the same what velocity dispersion curves shows initially in the work of F. Zwicky. The results also fit well with the results of Jakub Mielczarek et al[24]. Their exploration shows the vortex formation in the axion condensate and its effect on spiral shape galaxies. In present paper we compare our result with vorticity of Axion condensate.

2 illus, 28 ref

017043   Sharma B;Bora P K (Civil Engineering Dep, Assam Engineering College, Gauhati Univ, Assam, Email: binuaec@yahoo.co.in) : Determination of coefficient of consolidation from index properties of soil. Indian Geotech J 2009, 39(4), 424-35.

A generalized state parameter consisting of void ratio of soil generalized with respect to void ratio at liquid limit has been used to determine the coefficient of permeability and volume compressibility of reconstituted soils. From these values the coefficient of consolidation has been determined. The reasons for using the void ratio at liquid limit as a reference state have been stated. A comparison with the coefficient of consolidation values obtained from the conventional methods with those of the new method shows that, in general, the new method would give better estimates of the actual settlements using appreciably less time and effort.

8 illus, 20 ref

017042   Shanthi C;Barathan S;Jaiswal R;Arunachalam R M (Physics Dep, Sona College of Technology, Salem-636 005, Email: shanthi_rec@yahoo.co.in) : Study of surface morphology in DC and pulse plating of silver alloy. Indian J Engng Mater Sci 2009, 16(2), 128-32.

The objective of this work is to make a comparative study of dc and pulse plating of silver on silver alloy. The dc and pulsed electro deposition of silver on silver alloy is analyzed from an alkaline cyanide bath with brightener. Pulse duty cycles of 20 to 80%, at frequencies 10, 25, 50 and 100 Hz with peak current densities of 3.21, 3.75 and 4.55 A/dm^{2 are employed. The influences of peak current density on the thickness and current efficiency of the plating process are studied. The surface morphology is characterized by SEM and XRD. Less porosity and fine grains are formed by pulse plating compared to that formed by dc plating.}

7 illus, 1 table, 13 ref

017041   Sengwa R J;Sankhla S;Choudhary S (Physics Dep, J N V Univ, Jodhpur-342 005, Email: rjsengwa@rediffmail.com) : Dielectric characterization of solution intercalation and melt intercalation poly(vinyl alcohol)-poly(vinyl pyrrolidone) blend-montmorillonite clay nanocomposite films. Indian J pure appl Phys 2010, 48(3), 196-204.

Poly(vinyl alcohol) (PVA)-poly(vinyl pyrrolidone) (PVP) blend-montmorillonite (MMT) clay nanocomposite films up to 10 wt.% clay loading were synthesized by aqueous solution intercalation and melt compounding. Complex dielectric function, alternating current (ac) electrical conductivity and complex impedance of these films have been investigated as a function of clay concentration in the frequency range 20 Hz-1 MHz at 30°C. These films show significant decrease in the real part of relative dielectric function (ε') up to 3 wt. % MMT clay loading and at 5 wt.% their ε' values are found to be nearly equal to the PVA-PVP blend film. It is observed that the ε' values of PVA-PVP blend-MMT clay films are lower than the PVA-MMT clay film at the same clay concentration. The ac electrical conductivity of these films increases with increase of frequency. The dc conductivity of these films varies anomalously with increase of clay concentration. The complex impedance spectra suggest that the dielectric properties of these nanocomposite films are independent of electrode polarization effect in the experimental frequency range. A correlation between dielectric function, structural ordering and the effect of preparation route were explored by considering clay intercalation and exfoliation and the interactions between polymer and MMT clay. This study revealed that the dielectric constant values of these organic-inorganic nanocomposite films can be tuned by loading MMT clay in the polymers matrix, which also improves their physical and thermal properties.

7 illus, 50 ref

017040   Sengwa R J;Choudhary S;Sankhla S (Physics Dep, J N V Univ, Jodhpur-342 005, Email: rjsengwa@rediffmail.com) : Dielectric dispersion and ionic conduction in hydrocolloids of poly (vinyl alcohol)-poly(ethylene oxide) blend-montmorillonite clay nanocomposites. Indian J Engng Mater Sci 2009, 16(6), 395-402.

Relative complex dielectric function, electric modulus, alternating current (ac) electrical conductivity and complex impedance spectra of poly(vinyl alcohol) (PVA)-poly(ethylene oxide) (PEO) blend loaded with montmorillonite (MMT) clay nano-platelets up to 10 wt.% in aqueous colloidal suspensions are investigated over the frequency range 20 Hz - 1 MHz at 27°C. The relaxation time corresponding to electrode polarization and ionic conduction processes are determined from the complex spectra of intensive dielectric quantities. The direct current (dc) electrical conductivity of these materials is evaluated by the fitting of real part ac conductivity data to the Jonscher power law, which increases significantly at higher clay concentration. The behaviour of ionic conduction with increase of clay concentration is discussed considering intercalation of the polymers blend in clay galleries with the formation of lamellar nanostructures, and the effect of exfoliated MMT clay nanoplatelets on these structures. Contribution of PVA and PEO on the ionic conduction and electrode polarization phenomena is explored in the hydrocolloids of PVA-PEO blend -MMT clay from the comparative study of various dielectric parameters with the PVA-MMT clay and PEO-MMT clay hydrocolloids.

4 illus, 1 table, 48 ref

017039   Sengupta M (Physics Dep, North Eastern Regional Institute of Science and Technology, Nirjuli-791 109) : Higher derivative gauge invariance with spin-2 field. Bull Calcutta Mathl Soc 2009, 101(6), 603-6.

Using Weinberg's fundamental spin-field formalism, author suggest a higher derivative gauge connection with spin-2 field. This gives analogous to QED a renornializable field theory model of quantum gravity, who's non-unitarity problem can be dispensed with by Lee-Wick mechanism (Tombonlis, 1977, 1980).

4 ref

017038   Selvakumari T M;Emerson R N;Ganesan S (Physics Dep, Angel College of Engineering & Technology, Tirupur-641 665) : Magnetic properties and microstructural characterisation of nanostructured FePt films fabricated by electrodeposition. Int J pure appl Phys 2009, 5(2), 165-73.

The study of magnetic and microstructural characteristics of some nanostructured magnetic thin layers have fundamental importance to understand magnetization dynamics and is related to applications in micro electro mechanical system applications. This paper is devoted to the investigation of FePt alloy films by electrodeposition technique. High quality of deposit with low cost is the advantage of this technique. Structural analysis of the film was carried out using X-ray diffractometry & scanning electron microscopy. Elemental compositions of the film were studied using energy dispersive X-ray spectroscopy. Magnetic properties were studied using vibration sample magnetometer. The surface morphology, crystalline structure, grain size and magnetic properties of the plated films have been compared. The X ray analysis and magnetic measurements reveal the presence of hard and soft magnetic phase with various temperature for dc plated films. Thickness was measured by using digital micrometer. Hardness and adhesion of the film were also studied. Testing results shows that magnetic and structural properties depends upon the bath temperature, current density, annealing and composition ratio of Fe and Pt. Films are shiny and smooth. Reasons for variation in magnetic properties and structural characteristics were discussed.

2 illus, 4 tables, 12 ref

017037   Saxena N K;Khan M A;Nitendar Kumar;Pourush P K S (Physics Dep, Agra College, Agra-282 002, Email: nav3091@rediffmail.com) : 2 x 2 Array of circular patches patches on LiTiZn ferrite substrate. Indian J Sci Technol 2010, 3(2), 184-7.

Rectangular array of four elements of microstrip circular patches modeled on LiTiZn ferrite substrate is presented. Here we have considered LiTiZn ferrite as a substrate which has been synthesized by the solid state reaction technique (SSRT). In this paper we present a comparison of radiation pattern and other parameters when the antenna array is biased perpendicularly with varying magnetic field. The array antenna using LiTiZn with magnetic biasing, reports a reduction of radiation of side-lobes with increased directivity with better radiation power response.

8 illus, 2 tables, 10 ref

017036   Santhanam A;Balakrishnan M;Annadurai R A (Physics Dep, Govt. Arts College, Tiruvannamalai-606 603, Email: mbkarunmathi_ro@yahoo.co.in) : Configuration and phase space of classical helium atom in 2D. Indian J Sci Technol 2010, 3(2), 121-3.

Classical three body problem of helium atom is studied numerically in two dimensions. The orbits and phase space of the electrons for different initial conditions are investigated by solving the equations of motion numerically. The phase space shows interesting result of band structure similar to the quantum mechanical result of the solids. The variation of auto-ionization with perturbation parameter is also established.

3 illus, 1 table, 6 ref

017035   Santhanam A;Annadurai R A;Balakrishnan M (Physics Dep, Government Arts College, Tiruvannamalai-606 603, Email: mbkarunmathi_ro@yahoo.co.in) : Effect of mutual interaction anisotropy parameter on the system of collective motion. Indian J Sci Technol 2010, 3(2), 118-20.

Collective motion of birds is studied numerically. The effect of the anisotropy mutual interaction parameter plays a vital role on the order parameter of the collective motion of biological groups like birds, fishes etc. It is found that, if the interaction with the elements in front of a given element is stronger than with those behind, then the system will move as a single unit.

6 illus, 9 ref

017034   Sanjay;Kishore N;Agarwal A (Applied Physics Dep, Guru Jambheshwar Univ of Science and Technology, Hisar-125 001, Email: sanjay2000angira@yahoo.co.in) : Structural, optical and transport properties of semiconducting Fe₂O₃-PbO-B₂O₃ glasses. Indian J pure appl Phys 2010, 48(3), 205-11.

Semiconducting oxide glasses of compositions xFe₂O₃.(40-x)PbO.60B₂O₃ have been prepared by the standard melt-quenching technique over the range 0 ≤ x ≤ 20) (x is in mol%). The amorphous nature of the samples was ascertained using X-ray diffraction patterns. The structural changes in these glasses have been investigated by IR spectroscopy. The values of characteristic glass transition temperature (r_g) have been found from differential scanning calorimetry (DSC) traces and corresponding specific heat capacity (C_p) was also estimated. It is found that the density of these glasses decreases but glass transition temperature increases as Fe₂O₃ content is increased. The change in both the density and molar volume was discussed in terms of the structural modifications that take place in the glass matrix upon replacing PbO by Fe₂O₃ The dc conductivity of these samples was measured in the temperature range 473-623 K. In this temperature range, the dc conductivity increases from 10^-9 to 10^-4 S/m with increasing Fe₂O₃ content due to electron hopping from Fe(II) to Fe(III) ions. The values of the theoretical optical basicity of these glasses have also been determined.

6 illus, 2 tables, 43 ref

017033   Rao M C;Hussain O M (Physics Dep, Andhra Loyola College, Vijayawada-520 008, Email: raomc72@gmail.com) : Growth and characterization of tetravalent doped LiCoO₂ thin film cathodes. Indian J Engng Mater Sci 2009, 16(5), 335-40.

Titanium-doped LiCoO₂ thin films are grown by pulsed laser deposition technique on silicon substrates. Structure, AFM, FTIR and Raman are studied with respect to their deposition parameters, i.e., substrate temperature (T_s) and oxygen partial pressure (pO₂) in the deposition chamber. The films deposited in pO₂ =100 mTorr showed good crystallinity on silicon substrates maintained at T_s = 700°C. It is found that such a film crystallizes in the layered NaFeO2 structure. The influence of titanium doping on particle size and morphologies has been clearly studied. FTTR spectra displayed the characteristic IR dominant bands at 246 and 550 cm^-1 for titanium doped LiCoO₂ thin films. The Raman peaks observed for the films at 594 cm^-1 and 485 cm^-1 are ascribed to Raman active modes A_1g and E_g respectively. The electrochemical measurements were carried out on LiHLiTi_yCO_1-yO₂ cells. The LiHLiTi_yCo_1-yO₂ cell delivered a specific capacity of 225 mC/μm cm². The influence of titanium doping on the structural and electrochemical properties has been systematically studied.

5 illus, 19 ref

017032   Rao A;Sheeja Krishnan;Ganesh Sanjeev;Siddappa K (Physics Dep, Mangalore Institute of Technology and Engineering, Moodabidri-574 227, Email: asha_rao_i@yahoo.com) : Effect of 8 MeV electrons on Au/n-Si schottky diodes. Int J pure appl Phys 2009, 5(1), 55-62.

This paper presents the results of 8MeV electron irradiation effects on the electrical characteristics of Au/n-Si Schottky diodes. The diode parameters were calculated from the I-V and C-V characteristics. It is found that both forward and reverse current increases after irradiation. A decrease in the value of barrier height and increase in the ideality factor are observed with increase in electron dose. Capacitance - Voltage measurements indicate that there is a slight reduction in the carrier concentration due to electron irradiation.

5 illus, 1 table, 11 ref

017031   Ramasamy V;Rajkumar P;Ponnusamy V;Jose M T (Physics Dep, Annamalai Univ, Annamalainagar-608 002, Email: srsaranram@rediffmail.com) : Thermoluminescence study of recently excavated river sediments from Tamil Nadu, India. Indian J pure appl Phys 2010, 48(4), 256-63.

Thermoluminescence (TL) property of sediments from Vellar river which originates at Kalrayan hills of Salem district and terminates at the Bay of Bengal at Porto-Novo of Cuddalore district in Tamilnadu, has been studied. The samples of twenty seven sites were tested for natural thermoluminescence (NTL) and artificial thermoluminescence (ATL) studies. The NTL glow curve of all the samples shows only one peak at around 330°C. The sample irradiated with a gamma dose of 3.3 Gy and recorded with linear heating rate of 10°C/s shows additional peaks at around 135, 158 and 270°C. The TL intensity is found to decrease from origin to end point. The same trend is observed when the quartz samples are extracted from each site and from various grain sizes sieved samples. The TL intensity is the maximum at 300 and minimum at 53 μm grain size samples. The correlation made through FTIR and TL studies shows that the luminescence effect is found to decrease with decrease in grain sizes.

9 illus, 2 tables, 20 ref

017030   Rajesh Kumar;Pramjit Singh;Ali S A;Sharma A; Khan S A;Sonkawade R G;Rajendra Prasad (School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha Univ, Delhi-110 403, Email: rajeshkumaripu@gmail.com) : Swift heavy ion induced modification in makrofol-KG polycarbonate. Indian J pure appl Phys 2010, 48(3), 166-71.

Swift heavy ion (SHI) induced modifications in Makrofol-KG, a bisphenol a polycarbonate irradiated by 100 MeV Si^{8+ ion beam have been studied by UV-visible and FTIR spectroscopy and dielectric constant measurements. The absorbance in UV and visible range increases with ion fluence and the absorption edge shifts towards the visible region, indicating the carbonization of the material. Dielectric constant increases with ion fluences, implying an improvement in the orientational polarization of molecules. The FTIR spectra obtained after the irradiation exhibit an overall reduction of the intensities of the typical vibrational bands of pristine PC and the appearance of new bands.}

4 illus, 2 tables, 30 ref

017029   Rajesh Kumar (Physics Dep, Univ School of Basic & Applied Sciences, Guru Gobind Singh Indraprasth, Delhi-110 403, Email: rajeshkumaripu@gmail.com) : Nano scale free volume study of high energy (MeV) ion beam irradiated polyamide nylon-6 polymer. Indian J pure appl Phys 2010, 48(4), 233-9.

Characterization of the effect of energetic high energy heavy ion irradiation on free-volume parameters in polyamide nylon-6 polymer has been studied by positron annihilation lifetime measurements. The irradiation of polymeric materials with Swift Heavy Ions (SHI) results in to the change of their free volume properties which have strong correlation with their macroscopic properties. Positron Annihilation Lifetime Spectroscopy (PALS) provides direct information about the dimension, content and hole size distribution of free volume in polymers. Polyamide nylon-6 polymer films of thickness 250 μn were irradiated with 145 MeV Ne^{6+ ion beam at Variable Energy Cyclotron Centre (VECC), Kolkata, India to the fluences of 1011, 1012, 1013 ions/cm2. From the o-Ps parameters, average free volume hole radius, micro-void volume and fractional free volume were obtained. The values of o-Ps lifetime and therefore, the average free volume are found to decrease with ion fluences.}

5 illus, 2 tables, 23 ref

017028   Rajabi A A (Physics Dep, Shahrood Univ of Technology, P.O. Box 36155-316, Email: a.a.rajabi@shahroodut.ac.ir) : Nuclear field produced by relativistic harmonic oscillator light mesons. Int J pure appl Phys 2009, 5(1), 41-7.

The strong nuclear interaction does not depend on the electric charge. It seemes natural to assume that the nuclear introduction could be associated with the presence of special nucleon charge g in nucleons, and a harmonic oscillator (H.O.) for confinement. Getting a correct treatment, we consider the exchange of spin zero particles, the spin zero particle like π- meson field with harmonic oscillator potential interacts with nucleon through the Kelein -Gordon Fok equation (K.G.F). In this model, we can find the known strong nuclear interaction. Hence harmonic oscillator potential is a confinement potential, causes each nucleon surrounded by a cloud of mesons.

26 ref

017027   Palit A (NO, , P154 Motijheel Avenue, Flat c4, Kolkata-700 074) : Pair annihilation and self energy. Int J pure appl Phys 2009, 5(1), 69-78.

Electrostatic self energy has always been a problem of perplexing magnitude. Matters become more complicated when we try to view the problem of pair annihilation in relation to self energy in the light of the classical laws. Where does the self energy go to when pair annihilation takes place? The field theories try to solve this problem intelligently with the help of the virtual photons. The interaction between the charged particle and the virtual photons creates self energy which is taken care of by the Feynman-Diagrams. But is this representation accurate enough to replace the classical self energy in all its totality? Is it at all possible to explain the self energy problem with the classical laws? Such matters have been investigated in this article.

3 illus, 8 ref

017026   Padmavathy R;Rajendran K V;Sridevi D; Vijayalakshmi R;Anandan S;Gajendiran J (NO, Presidency College, Chennai-600 005, Email: rpadmavathy.suresh@gmail.com) : Non ionic surfactant on the surface modification of SnO₂ nanoparticles. Int J pure appl Phys 2009, 5(1), 79-83.

Nanoscale SnO₂ particles have been synthesized by simple hydrothermal method using a non-ionic surfactant PEG abbreviated as Polyethylene glycol at different pH. The samples were characterized by X-Ray diffratometer, UV-Vis absorption spectrometer and Field emission scanning micrograph. The prepared SnO₂ nanoparticles appear to be in single crystalline tetragonal in phase with the diameter ranging from 30-55 nm. The absorption spectra exhibited a blue shift due quantum confinement effect. The morphological changes with the variation in the pH values were studied.

3 illus, 15 ref

017025   Monteiro A P;Vijaya Kumar K B (Physics Dep, Mangalore Univ, Mangalagangothri, Mangalore-574 199, Email: kbvijayakumar@yahoo.com) : Semi-relativistic quark model fo light D wave mesons with instanton induced interaction. Indian J pure appl Phys 2010, 48(4), 240-4.

The mass spectrum of the D wave mesons has been investigated in the framework of Semi-Relativistic Quark Model (SRQM). The Hamiltonian used in the investigation has Lorentz scalar plus vector Harmonic potential, one-gluon-exchange potential (OGEP) and instanton induced quark-antiquark interaction (III). The calculated D wave meson masses are in agreement with the experimental D wave meson masses. The respective role of III and OGEP in the D wave meson spectrum has been studied.

4 tables, 17 ref

017024   Mohammadi M;Rokn-Abadi M R;Arbshahi H (Physics Dep, Ferdowsi Univ of Mashhad, Mashhad, Iran, Email: m_rezaee.roknabadi@yahoo.com) : Investigations on impact of post-heat temperature on structural, optical and electrical properties of Al-doped ZnO thin films prepared by sol-gel method. Indian J Sci Technol 2010, 3(2), 110-12.

Aluminum doped ZnO (AZO) thin films have been prepared by spin coating route on glass substrate. The structural, optical and electrical thin films have been characterized in different post-heat temperatures between 450 and 600°C. X-ray diffraction analysis has revealed hexagonal wurtzite structure with (002) preferred orientation which increased in crystallite size by increasing post-heat temperature. The optical spectra of the films showed the transmittance higher than 90% within the visible wavelength region. Our results show that optical gap and surface resistance of the films are decreased by increasing post-heat temperature.

5 illus, 1 table, 10 ref

017023   Mishra A;Parsai N;Soni N;Awate R (School of Physics, Devi Ahilya Univ, Indore-452 001, Email: amishra1960@yahoo.com.in) : Extended X-ray absorption fine structure data analysis of copper (II) complexes of 6-methyl-5-arylhydrazono-2-thio-4-oxo-pyridine ligand. Indian J pure appl Phys 2010, 48(2), 81-4.

A technique is presented for Extended X-ray absorption fine structure (EXAFS) data analysis for determining the metal-ligand bond length using conventional source. A theoretical EXAFS data analysis is carried out by Fourier analysis of experimental EXAFS data of some copper (II) complexes of 6-methyl-5-arylhydrazono-2-thio-4-oxo-pyridine. The analysis of EXAFS data is presented using MathCad programming and FEFFIT (Fitting of EXAFS by Fast Fourier Inverse Transform) programming. This analysis includes details of the Fourier transform of the data and the extraction of metal-ligand bond length. Bond lengths determined from these two data analysis methods are compared with the bond lengths obtained from several other known techniques.

4 illus, 1 table, 15 ref

017022   Markna J H;Vachhani P S;Shah N A;John J;Rama D S;Malik S K;Kuberkar D G (Physics Dep, Saurashtra Univ, Rajkot-360 005, Email: jaysukh28@rediffmail.com) : Size dependent modifications in the pysical properties of chemical solution deposition and pulsed laser deposition grown La_0.7Ca_0.3MnO₃ manganite thin films: a comparative study. Indian J Engng Mater Sci 2009, 16(2), 123-7.

Grain-size dependence of electronic transport and magnetorcsistance (MR) properties of nanostructurcd La_0.7Ca_0.3MnO₃ (LCMO) manganite thin films grown using pulsed laser deposition (PLD) and chemical solution deposition (CSD) have been compared in the context of the grain size, surface and strain modification due to the different synthesis techniques used as well as due to substrate induced magnetic anisotropy. CSD grown LCMO thin films shows the grain size ~70 nm while grain size ~150 nm is exhibited by PLD grown lllms resulting in an appreciable change in the strain and low temperature magnctoresistancc (LTMR). In CSD grown film, nanostructured grains exhibit sharp magnetic orientation in the absence of strain resulting in the observation of large maximum TCR value ~ 10.1% K^-1 at 235 K. as compared to PLD grown film (TCR value ~ 2.7% K^-1 at 194 K). Epitaxial thin films grown by the CSD technique are strain free and possess nanostructured grains size resulting into better physical properties as compared to PLD grown LCMO films.

7 illus, 2 tables, 18 ref

017021   Manjunath M S;Sivagurunathan P;Sannappa J (Physics Dep, Yuvaraja's College, Mysore Univ, Mysore, Karnataka, Email: manjumsphy@yahoo.com) : Studies of hydrogen bonding between N, N-dimethylacetamide and primary alcohols. Int J pure appl Phys 2009, 5(1), 63-7.

Hydrogen bonding between N, N-Dimethylacetamide (DMA) and alcohols has been studied in carbon tetrachloride solution by an X-band Microwave bench at 936 GHz. The dielectric relaxation time 1 of the binary system are obtained by both Higasi's method and Gopalakrishna method. The most likely association complex between alcohol and DMA is 1:1 stoichiometric complex through the hydroxyl group of the alcohol and the carbonyl group of amide. The results show that the interaction between alcohols and amides is 1:1 complex through the free hydroxyl group of the alcohol and the carbonyl group of amide and the alkyl chain-length of both the alcohols and amide plays an important role in the determination of the strength of hydrogen bond (O-H: C=O) formed and suggests that the proton donating ability of alcohols is in the order: 1-propanol < 1-butanol < 1-pentanol and the accepting ability of DMA.

2 illus, 1 table, 10 ref

017020   Manjunath M S;Sannappa J (Physics and Electronics Dep, Yuvaraja College, Mysore Univ, Mysore-570 001, Email: manjumsphy@yahoo.com) : Molecular interaction study of DMA and NMA with primary alcohols systems by X-band microwave. Int J pure appl Phys 2009, 5(1), 85-92.

Molecular interaction between NMA (N-methylacetamide) with 1- Alcohols and DMA (N, N-dimethylacetamide) with Primary Alcohols (1-Propanol, 1-Butanol, 1-Pentanol) has been studied in carbon tetrachloride by using X-band microwave bench at 936 Ghz and the orientation of molecular dipoles have been identified by Kirkwood correlation factor (g). The dielectric relaxation time τ of the binary system are obtained by both Higasi's method and Gopalakrishna method. The results show that the most likely interaction between alcohols and amides is 1:1 complex through the free hydroxyl group of the alcohol and the carbonyl group of amide and the alkyl chain-length of both the alcohols and amide plays an important role in the determination of the strength of hydrogen bond (O-H: C=O) formed.

2 illus, 1 table, 16 ref

017019   Mandal M K;Sarkar B C (Physics Dep, National Institute of Technology, Durgapur-713 104, Email: nitmkm@yahoo.co.in) : Ring oscillators: characteristics and applications. Indian J pure appl Phys 2010, 48(2), 136-45.

The structure and operating principle of ring oscillators (RO) have been described. The expression for the frequency of oscillation of a complementary metal oxide semiconductor (CMOS) delay cell based conventional ring oscillator is presented and propagation delay of the delay stages is calculated. The limitations of a conventional RO have been studied and a few techniques to overcome these limitations have been mentioned. In this context, some modified structures of ring oscillators such as negative skewed delay RO, multi feedback RO, coupled RO are described for high frequency oscillation. The effect of noise sources on the output of ring oscillators has also been studied. Some potential applications of such ring oscillator based on its voltage tuning characteristics and multiphase outputs are also mentioned.

9 illus, 25 ref

017018   Madhav M R;Suresh K;Nirmala Peter E C (Prof. Emeritus, JNTUH College of Engg., Kukatpally, Hyderabad-500 085, Email: madhavmr@gmail.com) : Analysis of effect of creep on response of granular pile reinforced ground. Indian Geotech J 2009, 39(4), 399-423.

Creep or secondary compression is a very important phenomenon in clays, organic soils and peat. The paper presents an analysis of granular pile reinforced ground with in situ soil undergoing creep and assuming the swelling or rebound on unloading to be negligible, i.e. C_s = 0. The variations of settlement reduction factor, settlement of the reinforced ground, the load sharing between the GP and the in situ soil, the stress concentration ratio, granular pile - in situ soil interface shear stress, void ratio versus log effective stress, etc., with time, area ratio, and stiffness factor are estimated and presented. Results indicate the in situ soft ground gets unloaded due to creep, another beneficial aspect of treating soft soils with granular piles.

19 ilus, 18 ref

017017   Kumar Y;Mohiddon A;Srivastava A;Yadav K L (Physics Dep, Indian Institute of Technology, Roorkee-247 667, Email: klalyfph@iitr.ernet.in) : Effect of Ni doping on structural and dielectric properties of BaTiO₃. Indian J Engng Mater Sci 2009, 16(6), 390-4.

Polycrystalline samples of Ba_1-xNi_xTiO₃ (BNT), where x = 0, 0.03, 0.05, 0.07 and 0.10 have been synthesized by solid-state reaction technique. No phase change in the crystal structure has been observed with Ni doping in barium titanate up to x = 0.10, however a decrease in crystallite size, lattice strain, c/a ratio and grain size has been found with Ni doping. The different results presented may be related to, and are explained by, the grain size and its distribution in the ceramic bulk. Ni doping in BaTiO₃ exhibit many interesting features, such as shift in transition temperature, increasing diffuse phase transition and decreasing dielectric constant. The evolution from a normal ferroelectric phase transition to a diffuse phase transition has been observed with increasing Ni concentrations. The dielectric study of samples poled in magnetic field (data shown for BNT, x = 0.03 here) suggests that T_c and maximum dielectric constant increase with increasing magnetic poling strength along with decreasing nature of diffusivity thus showing multiferroic nature.

5 illus, 2 tables, 21 ref

017016   Kumar N;Kumar V;Arora M;Sharma M;Singh B;Pant R P (National Physical Laboratory (CSIR), Dr KS Krishnan Road, New Delhi-110 012, Email: rppant@mail.nplindia.ernet.in) : Synthesis of Mn_0.2Zn_0.8Fe₂O₄ particles by high energy ball milling and their applications. Indian J Engng Mater Sci 2009, 16(6), 410-14.

Ultra fine Mn_0.2Zn_0.8Fe₂O₄ magnetic particles are developed by high energy ball milling technique and investigated for physical properties. The crystalline phase, crystallite size, surface morphology, metal oxide bonding and porosity of these magnetic particles are analyzed. The porosity increases on increasing the grinding period due to decrease in the particle size and crystallinity reduces. The IR spectra measured in the range of 4000-400 cm^-1 exhibit symmetric stretching mode of (FeO₄) and (ZnO₄) tetrahedral at 669.7 cm^-1 and 545.6 cm^-1. The lattice strain induced by ball milling process has been determined. The porosity plays an important role in chemisorption and physisorption of species on the sites of the particles. This property of these particles has been exploited for the applications of humidity sensor.

4 illus, 4 tables, 14 ref

017015   Kumar M S;Sharma B S (Physics Dep, Institute of Basic Sciences, Khandari, Agra-282 002, Email: mskumar43@yahoo.co.in) : Modified ghiorso equation of state for CaMgSi₂O₆ silicate melt at 1673 K. Indian J pure appl Phys 2010, 48(4), 282-6.

Ghiorso has recently developed a functional form for an equation of state (EOS) of molten silicate liquids. The EOS is designed for application over a wide range of melt compositions which can be used from reference conditions to very high pressures. It is emphasized here that the Ghiorso EOS does not satisfy the thermodynamic boundary conditions at infinite pressure. Ghiorso EOS has been modified to make it consistent with the Stacey thermodynamics at extreme compression. Various relationships between the compression ratio (V/V₀) and pressure P have been studied for the silicate melt CaMgSi₂O₆ at 1673 K. The pressure-volume isothermal relationship, isothermal bulk modulus K and its pressure derivative have been calculated using five different forms of EOS viz. Birch Murnaghan third order EOS, Vinet-Rydberg EOS, Stacey EOS, Ghiorso EOS and the modified Ghiorso EOS. It is found that the modified Ghiorso EOS developed in the present study gives the satisfactory results which is in good agreement with the Stacey reciprocal-A' EOS.

3 illus, 1 table, 16 ref