024134   Arun Vijayakumar D (Vaccum and Pressure Standards, National Physical Laboratory, , New Delhi-110 012) : Evaluation of uncertainty in pressure and vacuum measurements using direct comparison and least square error fitting methods. MAPAN 2006, 21(1), 23-36.

Present day Quality Culture demands adherence to IS0/1EC-17025 standard, where evaluation and reporting of measurement uncertainty of all measuring instruments with measurement traceability is stipulated as mandatory. This can be accomplished through the measurement process called "Calibration ". All National Metrological Institutes (NMI) and accredited calibration Laboratories are continuously in receipt of measuring instruments of different parameters from Industries, Institutions and Public sector undertakings for calibration. In calibration of pressure and vacuum instruments, Direct Comparison and Least Square Error Fitting are the most commonly used methods. As the demand for calibration certificates with measurement uncertainty and traceability is increasing day by day, an effort is made towards extraction of all information regarding repeatability, hysteresis, degrees of freedom, expanded measurement uncertainty from the raw data collected against the selected reference standard. Since the uncertainty components of some variableslfactors are parameter independent, an effort is also made to keep them separate from the parameter dependent components while reporting the expanded measurement uncertainty.

1 illus, 11 tables, 4 ref

024133   Arora M;Gupta S K (EPR Spectroscopy Group, Materials Characterization Div, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi-110 012) : Estimation of overall uncertainty in spin concentration measurement of paramagnetic centres in different materials by EPR spectroscopy. MAPAN 2006, 21(1), 17-21.

Electron Paramagnetic Resonance (EPR) is a very specialized and sensitive technique for detecting and characterizing paramagnetic centres/impurities in different materials like amorphous, irradiated, doped semiconductors, thin films, conducting polymers or biological systems etc. In these studies, author have made effort to identify and quantify all the sources of random and systematic uncertainty involved in evaluating the spin concentration of paramagnetic defects from the EPR spectrum more near to its true value. Sample preparation, storage conditions, instrument stability, environmental conditions like temperature, humidity, power supply instabilities, calibration effects with respect to standard reference material, magnetic field value, calibration of balance, effect of analyst and random effects like different parameters were considered in the evaluation of spin concentration of paramagnetic centres/defects present in a material under study. Sample preparation, storage conditions and instrument stability were checked by maintaining the same environmental conditions and repeatability of recording data. Purity of standard reference material, magnetic field value and uncertainty associated with digital weighing balance were taken from the 11IJlnu.facturer's calibration certificate/literature recommendations. The overall uncertainty was calculated by using the standard available procedure for the calculation of spin concentration of paramagnetic defects in different materials.

3 tables, 22 ref

024132   Alok Kumar (NO, Institute of Phys, Bhubaneswar-751 005) : 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

024131   Ajeetha N;Veerabhadra Reddy K;Ojha D P (Liquid Crystal Research Lab, Post-Graduate Physics Dep, Andhra Loyola College, Vijayawada-520 008, Email: durga_ojha@hotmail.com) : Role of dielectric medium on 4-methoxybenzylidene - 4'-acetoxyaniline (MBAA) - a computational analysis. Bull pure appl Sci-Sect D 2006, 25(2), 93-9.

Molecular geometry of MBAA has been constructed on the basis of the published crystallographic data with the standard values of bond length and bond angles. The evaluation of atomic charge and dipole moment at each atomic centre has been carried out through the Complete Neglect Differential Overlap (CNDO/2) method. The modified Rayleigh-Schrodinger perturbation theory along with multicentered-multipole expansion method has been employed to evaluate longrange interactions while a `6-exp' potential function has been assumed for shortrange interactions. The total interaction energy obtained through these computations were used to calculate the probability of each configuration in dielectric medium (i.e., non-interacting and non-mesogenic solvent, benzene) at room temperature (300K). It has been observed that in dielectric medium the energies/probabilities are redistributed and there is a considerable rise in the probability of interactions, although the order of preference remains the same. Offers a theoretical support to the experimental observations. Also, this provides a new and interesting way of looking at the liquid crystalline molecules in dielectric medium.

3 illus, 1 table, 15 ref

024130   Ahire R R;Chavhan S D;Lokhande C D;Sharma R P (Thin Film and Semiconductor Lab, Phys Dep, G.T. Patil Coll, Nandurbar-425 412) : Growth, structural, optical and electronic transport properties of CdS thin films deposited by modified chemical bath deposition method. J Adv Sci Technol 2006, 9(1-2), 17-27.

Modified chemical bath deposition method has been used to deposited cadmium sulfide (CdS) thin films and the films have thickness about 0.14 1m under the optimized deposition conditions. X-ray diffraction pattern shows that deposited films were turned from cubic to hexagonal structure in annealed thin films at 300°C in air for 1 h. These films were characterized by means of atomic forced microscopy (AFM), optical absorption and electrical measurement techniques. The results were confirmed from the reported standard data.

9 illus, 2 tables, 8 ref

024129   Acharya R S;Naik S D (NO, VIIT, Pune-411 048) : Motion analysis during sabot opening process. Def Sci J 2007, 57(2), 229-41.

For FSAPDS projectile, the trajectory and stability are dependent on different forces in different phases of the motion. During the first phase gravity, aerodynamic drag along with propellant gas force affect the motion. The motion is influenced by shock wave and mechanical force in sabot opening phase and the effect of time lag during opening of sabots also forms part of this work.

6 illus, 1 table, 5 ref

024128   Abdelaziz Y A (Thermometry Dep, National Inst for Standards, Egypt) : Stability caracterisistcs of Industrial platinum resistance thermometers supplied by different manufacturers. MAPAN 2006, 21(1), 3-7.

Stability characteristics of five industrial platinum resistance thermometer "IPRT" elements supplied by three different manufactures were investigated in the temperature range 0 to 450°C. The study is helpful in comparing the results of IPRT elements of different designs. Studies also showed that the thermometers of higher ∝ have better stability. Annealing of thermometers before use for at least 40 hours at 450°C is very important to achieve stability in the range from 20 to 60 mK.

2 illus, 2 tables, 8 ref

023159   Yadav R R;Pandey D K (Physics Dep, Allahabad Univ, Allahabad-211 002) : Ultrasonic properties of bita-phase nickel aluminide. J pure appl Ultrasonics 2006, 28(1), 4-11.

The ultrasonic attenuation due to phonon-phonon interaction has been evaluated in β-phase NiAl in high temperature interval 300-1400K along the crystallographic directions <100>, <110> and <111> for longitudinal and shear waves. For this evaluation Authors have calculated second and third order elastic constants (SOEC and TOEC) at the different temperatures using only two basic parameters. Ultrasonic velocities and Non-linearity parameters are calculated using the elastic constants. Structural stability, abrupt change in ductility, disordering at T_c may be predicted on the basis of temperature variation of the elastic constants and the ultrasonic attenuation.

5 tables, 4 illus, 19 ref

023158   Yadav N;GHosh S (School of Studies in Phys, Vikram Univ, Ujjain-456 010) : Diffusion-induced parametric dispersion and amplification in doped semiconductor plasmas. Pramana J Phys 2007, 68(1), 123-8.

Using the hydrodynamic model of semiconductor plasma, the diffusionª induced nonlinear current density and the consequent second-order effective susceptibility are obtained under off-resonant laser irradiation. The analysis deals With the qualitative behaviour of the anomalous parametric dispersion and the gain profile with respect to the excess doping concentration and pump electric field. The analysis suggests that a proper selection of doping level and pump field may lead to either positive or negative enhanced parametric dispersion, which can be of great use in the generation of sequeezed states. It is found that gain maximizes at moderate doping concentration level, which may drastically reduce the fabrication cost of parametric amplifier based on this interaction.

2 illus, 15 ref

023157   Waghmare R V;Belsare N G;Raghuwanshi F C; Shilaskar S N (Physics Dep, Vidya Bharti Mahavidyalaya Camp, Amravati-444 602, Email: rvwaghmare@rediffmail.com) : D.C. electrical conductivity of paranitroaniline doped (1 : 1) polyvinylchloride and poly (methyl methacrylate) polyblends. Bull Mater Sci 2007, 30(2), 167-72.

Electrical properties of PVC, PMMA and their 1:1 polyblends, before and after adding parani-troaniline into them, have been investigated as a function of temperature, electric field and dopant concentration, to study the mechanism of electrical conduction. The current was measured by applying d.c. voltage in the range 25-800 V at various thermostatically controlled temperatures (313-373 K). The results obtained predict the Schottky-Richardson conduction mechanism to be operative and d.c. conductivity of the blend lies intermediate between those of individual components. Further, the conductivity of the blend increases with temperature and applied electric field and also with the increase in concentration of dopant. To identify the mechanism governing the conduction, the activation energies in low temperature (LTR) and high temperature (HTR) regions have been calculated. The dielectric constant of the sample at various temperatures have been calculated which increased with increase in temperature. This is indicative of the diffusion of ions in space charge polarization at higher temperature. The study of XRD and FTIR supports the changes occurring in the conductivity of the blend.

5 illus, 14 ref

023156   Ubale A U;Sangawar V S;Kulkarni D K (Physics Dep, Govt. Vidarbha Institute of Science and Humanities, Amravati-444 604, Email: ashokuu@yahoo.com) : Size dependent optical characteristics of chemically deposited nanostructured ZnS thin films. Bull Mater Sci 2007, 30(2), 147-51.

ZnS thin films of different thicknesses were prepared by chemical bath deposition using thiourea and zinc acetate as S^2- and Zn²⁺ source. The effect of film thickness on the optical and structural properties was studied. The optical absorption studies in the wavelength range 250-750 nm show that band gap energy of ZnS increases from 3-68-4-10 eV as thickness varied from 332-76 nm. The structural estimation shows variation in grain size from 6.9-17.8 nm with thickness. The thermo emf measurement indicates that films prepared by this method are of n-type.

9 illus, 18 ref

023155   Tomar B S;Tripathi R;Goswami A (Radiochem Div, Bhabha Atomic Res Centre, , Mumbai-400 085, Email: bstomar@barc.gov.in) : Odd-even effect in fragment angular momentum in low-energy fission of actinides. Pramana J Phys 2007, 68(1), 111-16.

Quantitative explanation for the odd-even effect on fragment angular moªmenta in the low-energy fission of actinides have been provided by taking into account the single particle spin of the odd proton at the fragment's scission point deformation in the case of odd-Z fragments along with the contribution from the population of angular momentum bearing collective vibrations of the fissioning nucleus at scission point. The calculated fragment angular momenta have been found to be in very good agreement with the experimental data for fragments in the mass number region of 130-140. The odd-even effect observed in the fragment angular momenta in the low-energy fission of actinides has been explained quantitatively for the first time.

1 illus, 1 table, 21 ref

023154   Tarcea N;Sbanski O;Robling G;Popp J (NO, Institut fur Physikalische Chemie, Universitat Wurzburg, Am Hubland, 97074 Wurzburg, Germany) : Device for microcapsule sizing by elastic light scattering. Asian J Phys 2006, 15(2), 259-65.

Elastic light scattering measurements provide a possible way of determining properties such as core size, shell size and refractive index. The design and construction of a device capable of measuring the above mentioned parameters for a core-shell particle is described here. The basic principle of measurement for the device proposed here consists of analyzing one particle at a time by recording the elastic light scattering pattern at angles between approx. 60° and 120°. By comparing the experimentally recorded phase functions with the previously calculated phase functions stored in a database, the geometry of the scattering object can be identitied. In our case the geometry is characterized by two parameters: the shell thickness and the core radius.

5 illus, 18 ref

023153   Szafran M;Koput J;Szafran Z D (Faculty of Chemistry, A. Mickiewiez University, Grunwaldzka 6, 60-780 Poznan, Poland, Email: szafran@amu.edu.pl) : DFT calculation of structure and vibrational spectrum of 1-methylisonicotinic acid chloride. Asian J Phys 2006, 15(2), 253-8.

The geometry. frequency and intensity of the vibrational bands of I-methylisonicotinic acid chloride and its deutero derivative were obtained by the density functional theory (DFT) with B3LYP functional using the 6-311++G(d.p) basis set. Good agreement between the calculated and experimental spectra has been obtained. Unequivocal assignment of the experimental infrared bands is performed on the basis of the potential energy distribution (PED).

2 illus, 2 tables, 18 ref

023152   Sujatha S;Babu G S D;Ananthamurthy S (NO, M.P. Birla Institute of Fundamental Research, Bangalore-560 001) : Mass function of open clusters NGC 1857 and Czernik 25. Bull Astr Soc India 2006, 34(4), 357-73.

The first CCD photometric UBVRI observations of the open clusters NGC 1857 (Czernik 20, OCl 427) and Czernik 25 (OC1 493) are presented. The observations were obtained on 28 November 2003 with the 2m Himalayan, Chandra Telescope at Hanle using a LN2 cooled 2k x 2k CCD. The colour excess E (B-V) is found to be non-uniform in the line of sight of NGC 1857 ranging between 0.38 and 0.60 mag, while it is 0.69 mag for Cz 25. Further, the clusters NGC 1857 and Cz 25 are estimated to be at a distance of 5.75±0.8 kpc and 4.79±0.5 kpc respectively. As the log (age) of NGC 1857 is estimated to be in the range of 8.00 to 8.25 and that of Cz 25 is 8.45, they may be considered to be of intermediate age. The luminosity function (LF) and the mass function (MF) for both the clusters have been derived. The MF slopes for the clusters NGC 1857 and Cz 25 are -2.39±0.26 and -2.70±0.25 respectively. These values are in fair agreement with that given by Salpeter. Mass segregation is observed in both the clusters and it could be due to the dynamical evolution of the clusters or the imprint of star formation process or both.

3 tables, 9 illus, 30 ref

023151   Sravana Kumar D;Krishna Rao D (Physics Dep, Acharya Nagrarjuna Univ, Nagarjunanagar-522 510, Email: gurukripadsk@yahoo.com) : Study of molecular interactions and ultrasonic velocity in mixtures of some alkanols with aqueous propylene glycol. Indian J pure appl Phys 2007, 45(3), 210-20.

Ultrasonic velocity, density and viscosity are experimentally determined in the mixtures of methanol/ethanol with aqueous propylene glycol (4.5m and 1.5m) over entire range of composition at 303.15K. Several acoustic and thermodynamic parameters such as excess viscosity, excess adiabatic compressibility, excess free volume, excess molar volume, excess enthalpy, excess free length, viscous relaxation time have been calculated to study nature and extent of molecular interactions in these mixtures. Ultrasonic velocities theoretically evaluated using Nomoto's relation, Van Dael and Vangeel's ideal mixing relation, impedance relation, Jacobson's equation, Rao's specific sound velocity relation and Junjie's equation are compared with experimental values to check applicability of these equations to the systems studied. The departure of experimental values of ultrasonic velocities from theoretical values is further analyzed to investigate molecular interactions. Two types of polynomial equations are fitted to experimental values of ultrasonic velocities. These polynomial representations of sound velocities have extremely small deviations from experimental values.

7 tables, 16 illus, 23 ref

023150   Sinha K P (Physics Dep, Indian Institute of Science, Bangalore-560 012, Email: kpsinha@gmail.com) : High temperature superconductivity in Pd-[H(D)]x system. Natn Acad Sci Lett 2006, 29(3-4), 125-9.

Theoretical model involving phonon and lochon (local charged boson) mediated pairing of electrons in Pd(H/D)_x is suggested to explain the possible observation of superconductivity in the range 51K<<60>cmax ≤295K (when x exceeds unity). In the combined mechanism the lochons have transient existence on (H⁺/D⁺) resulting in (H^-/D^-) species. The coupling parameter λ₁ for lochon induced processes depend linearly on x. The model explains the observation of the enhancement of T_c for x varying from 0.6 to 1.6. While the experimental observations are of great importance, it is desirable that other experimental groups confirm the results.

2 illus, 21 ref

023149   Singh U P;Thakur A N;Singh S V;Kumar S C (Phys Dep, T.D.P.G. Coll, Jaunpur) : Electrical conductivity and thermoelectric power of cerium-iron-transition metal mixed oxides. Ultra Scient phys Sci 2007, 19(1), 129-38.

The compounds of Cerium-iron-transition metal mixed oxides of the type CeFeTO₄ (Where T= Fe, Cr, Mn, Co) have been prepared by solid state reaction technique and characterized by XRD pattern. The electrical conductivity σ and thermoelectric power (S) measurements on the pressed pellets have been reported in the temperature range 400 to 1200K. It has been found that these compounds are essentially electronic conductors with a values lying in the range 10^-7 to 10^-3 Ω^-1 m^-1 around 400K. The maximum value of σ has been observed for CeFeMnO₄ and lowest for CeFe₂O₄. The log σT vs T^-1 and S vs T^-1 plots have three temperature region separated by break temperatures T₁ and T₂ which are same in both the plots. The sign of S shows that charge carriers are electrons in the studied temperature range. The electrical conduction in first range (T <60>T₁) is extrinsic and occurs due to donor type centers. In the second (T₁ <60>T <60>T₂) and third (T<62>T₂) ranges, electrical conduction is hopping type and occurs due to hopping of electrons from Fe²⁺ to Fe³⁺ in CeFe₂O₄, CO²⁺ to Fe³⁺ in CeFeCoO₄, Fe²⁺ to Cr³⁺ in CeFeCrO₄ and Mn³⁺ to Mn⁴⁺ centers in CeFeMnO₄ in the temperature range T₁<60>T<60>T₂ and from Fe⁺² to Mn³⁺ centers in the T<62>T2.

1 illus, 4 tables, 30 ref

023148   Singh S N;Thakur A N;Singh K (Phys Dep, T.D.P.G. Coll, Jaunpur-222 002) : Cylindrical shock waves in radiation gasdynamics. Ultra Scient phys Sci 2007, 19(1), 69-72.

The problem of explosion along a line in a gas cloud investigated. Similar solutions have been developed describing, the propagation of a Cylindrical shock in non-uniform atmosphere taking counter gas pressure and radiation flux into account. Results are illustrated through figures. The nature of flow variables can be studied easily by these figures.

4 illus, 6 ref

023147   Singh M;Kulsherstha V;Anil Kumar;Acharaya N K;Vijay Y K (Thin Films and Membrane Sci Lab, Phys Dep, University of Rajasthan, Jaipur-302 004) : The kinetics of Cr layer coated on TiNi films for hydrogen absorption. Pramana J Phys 2007, 68(1), 75-87.

The effect of hydrogen absorption on electrical resistance with temperature for TiNi and TiNi-Cr thin films was investigated. The TiNi thin films of thickness 800 Angstrom were deposited at different angles (θ = 0°, 30°, 45°, 60° and 75°) under 10^-5 Torr pressure by thermal evaporation on the glass substrate at room temperature. A layer of Cr of thickness 100 Angstrom was coated on the TiNi thin films. The changing rate of hydrogen absorption increases after Cr layer coating because Cr enhances the catalytic properties of hydrogen absorption in thin films. The rate of hydrogen absorption increases with temperature at lower range but at higher range of temperature it was found to decrease and also it was found that the hydrogen absorption increases with angle of deposition.

3 illus, 26 ref

023146   Singh G S;Bajpai R P (Advanced Optical Processing Div, Central Scientific Instruments Organi, , Chandigarh-160 030, Email: gssingh55@yahoo.com) : Design considerations of two components mechanically compensated zoom lenses. J Optics 2006, 35(1), 18-35.

Described simple method developed to solve the problem of determining the kinematics of two-component mechanically compensated zoom lenses. It has been shown that a simple paraxial conjugate equation, along with magnification equation can be used successfully to solve the complex problem of component displacement in a two components mechanically compensated zoom lens. This method provides a deep insight into the image formation process by a zoom lens. The method developed is simple to program and provide excellent information about working of two-component mechanically compensated zoom lenses.

14 tables, 5 illus, 5 ref

023145   Singh G S;Bajpai R P (Advanced Optical Processing Div, Central Scientific Instruments Organi, , Chandigarh-160 030, Email: gssingh55@yahoo.com) : Design consideration of three component mechanically compensated zoom lenses. J Optics 2006, 35(1), 1-17.

Presented a simple method to determine the power and air space distribution for three component mechanically compensated zoom lens. Also this paper describes a method developed to solve the complex problem of kinematics determination of three-component mechanically compensated zoom lenses. It has been shown that a simple paraxial conjugate equation, along with magnification equation can be used successfully to solve the problem of component displacement in a three component mechanically compensated aoom lens. This method provides a deep in sight into the image formation process by a zoom lens.

7 tables, 5 illus, 3 ref

023144   Simon V;Eniu D;Grecu R;Simon S (Physics Department, Babes-Bolyai University, Simon S) : Environment changes around the cations of yttrium aluminosilicate glasses doped with gadolinium. Asian J Phys 2006, 15(2), 247-51.

Short-range order and local atomic configuration in charge-balanced yttrium-aluminosilicate glasses doped with gadolinium were studied by infrared (IR) spectroscopy and Gd³⁺ electron spin resonance (EPR) on as prepared and heat treated samples. Yttrium and gadolinium cations occupy modifier sites in the aluminosilicate glass matrix. The silicate and aluminate units appear structurally relaxed after heat treatment. The new IR bands recorded from heat treated samples are associated with stretching modes of AlO₆ octahedra. At the same time the EPR results evidence the increase of gadolinium coordination as effect of structural relaxation.

5 illus, 1 table, 13 ref

023143   Shrivastava P K (Phys Dep, Govt. Model Sci Coll, Rewa-483 001, Email: pankaj_in_2001@rediffmail.com) : High speed solar wind streams and transient decreases in cosmic ray intensity. Ultra Scient phys Sci 2007, 19(1), 151-2.

High Speed Solar Wind Streams (HSSWS) is one of the sun oriented interplanetary phenomena, which produces short-term modulation in cosmic ray intensity. Identifies forty two events of sudden storm commencements (SSC) associated HSSWS for the period of 1996 to 2002. Daily values of kiel neutron monitor data have been used in chree analysis to derive these HSSWS on cosmic ray intensity on short-tenn basis. It has been investigated that these streams produce transient decrease in cosmic ray intensity. Transient decreases are found much larger during the period of high solar activity.

^ssc1 illus, 4 ref

023142   Shrivastava P K (Phys Dep, Govt Model Sci Coll, Rewa-483 001, Email: pankaj_in_2001@rediffmail.com) : Association of bright loop coronal mass ejections with major solar flares and Forbush decreases of cosmic ray intensity. Ultra Scient phys Sci 2007, 19(1), 57-60.

Major solar flares events have been taken to study solar longitudinal frequency distribution of the solar flares in eastern and western hemisphere on the solar disc for the period of 1996 to 2003. A statistical analysis has been performed to obtain the relationship between bright loop Coronal Mass Ejections (CMEs) and Major Solar Flares. Almost equal distribution of solar flares in association with CMEs are found in both the eastern and western hemisphere. In further analysis, it has been investigated that larger number of solar flares located in western hemisphere in association with CMEs are found to be more effective in producing Forbush effects in cosmic ray intensity.

2 illus, 12 ref

023141   Sharma A;Verma R C (Physics Dep, Punjabi Univ, Patiala-147 002, Email: arvind_kks1rediffmail.com) : Exclusive weak hadronic decays of charmed baryons in flavor SU (3) reanalyzed. Indian J pure appl Phys 2007, 45(3), 189-97.

Two-body exclusive weak hadronic (1/2⁺→1/2⁺ + 0^- decays of the charmed baryons Λ⁺_c , Ξ⁺_c and Ξ⁰_c are studied employing the SU(3) flavor symmetry. Using the available experimental data on Λ⁺_c→ΛJJ^{+< D>/∑+π0/<65> °K+ decays to fix the reduced amplitudes, predictions are obtained for the branching ratios and asymmetries in the Cabibbo-favored (CF), Cabibbo-suppressed (CS), and Cabibbo-doubly-suppressed (CDS) decay modes. Results obtained are consistent with the available data.}

2 table, 33 ref

023140   Sangawar V S;*Dhokne R J;Ubale A U; Chikhalikar P S;Meshram S D (Physics PG Dep, Govt. Vidarbha Institute of Science and Humanities, Amravati-444 604, Email: raginidhokne@yahoo.co.in) : Structural characterization and thermally stimulated discharge conductivity (TSDC) study in polymer thin films. Bull Mater Sci 2007, 30(2), 163-6.

Electrical conductivity of naphthalene doped polystyrene (PS) films (≈ 61.58 μm thick) was studied as a function of dopant concentration and temperature. The formation of charge transfer (CT) complexes and strong concentration dependence of carrier mobility point out that the current carriers are transported through doped polymer system via hopping among sites associated with the dopant molecules. The activation energy, E_a, was calculated from the graph of log σ vs 10³/T plot within low and high temperature regions.

1 table, 2 illus, 14 ref

023139   Samarasekara P;Yapa N U S;Kumara N T R N; Perera M V K (Physics Dep, Ruhuna Univ, Matara, Sri Lanka, Email: pubudus@phy.ruh.ac.lk) : CO₂ gas sensitivity of sputtered zinc oxide thin films. Bull Mater Sci 2007, 30(2), 113-6.

For the first time, sputtered zinc oxide (ZnO) thin films have been used as a CO₂ gas sensor. Zinc oxide thin films have been synthesized using reactive d.c. sputtering method for gas sensor applications, in the deposition temperature range from 130-153°C at a chamber pressure of 8.5 mbar for 18 h. Argon and oxygen gases were used as sputtering and reactive gases, respectively. ZnO phase could be crystallized using a pure metal target of zinc. The structure of the films determined by means of X-ray diffraction method indicates that the zinc oxide single phase can be fabricated in this substrate temperature range. The sensitivity of the film synthesized at substrate temperature of 130°C is 2.17 in the presence of CO₂ gas at a measuring temperature of 100°C.

3 illus, 15 ref

023138   Samant K M;Haram S K;Kapor S (Chem Dep, Univ of Pune, Ganeshkhind, Pune-411 007) : Synthesis of carbon nanotubes by catalytic vapor decomposition (CVD) method: optimization of various parameters for themaximum yield. Pramana J Phys 2007, 68(1), 51-60.

Describes an effect of flow rate, carrier gas (H₂, N₂ and Ar) composition, and amount of benzene on the quality and the yield of carbon nanotubes (CNTs) formed by catalytical vapour decomposition (CVD) method. The flow and mass control of gases and precursor vapors respectively were found to be interdependent and therefore crucial in deciding the quality and yield of CNTs. We have achieved this by modified soap bubble flowmeter, which contIolled the flow rates of two gases, simultaneously. With the help of this set-up, CNTs could be prepared in any common laboratory. Raman spectroscopy indicated the possibilities of formation of single-walled carbon nanotubes (SWNTs). From scanning electron microscopy (SEM) measurements, an average diameªter of the tube/bundle was estimated to be about 70 nm. The elemental analysis using energy dispersion spectrum (EDS) suggested 96 at.wt.% carbon along with ca. 4 at.wt. % iron in the as-prepared sample. Maximum yield and best quality CNTs were obtained using H₂ as the carrier gas.

8 illus, 35 ref

023137   Rugmini Radhakrishnan S (Phys Dep, Avinashilingam Univ for Women, Coimbatore-641 043) : Fabrication and study of a dual purpose solar dryer. Ultra Scient phys Sci 2007, 19(1), 79-82.

Deals with the study of a low cost dual-purpose solar dryer cum cooker with a reflecting mirror, fabricated with a view of dehydrating fruits/ vegetables and also for cooking. Performance analysis of this improved dryer reveals that the materials could be dehydrated at a faster rate compared to the open traditional sun drying. It is also found that the dual purpose dryer took only six hours to deprive of the moisture content of 1 Kg of potato, Mango etc from 75% to 20%. In open sun drying, the moisture content is reduced from 75% to 70% only for the same mass of the same material within the same time on the same day. The dual-purpose device is also tested for its cooking efficiency loaded with different foodstuff with and without the booster mirror. The details of the design as well as performance studies of the improved dryer have been reported.

1 illus, 1 table, 6 ref

023136   Roshan Lal;Suman ;Sharma N D;Taneja S P;Reddy V R (Physics Dep, Kurukshetra Univ, Kurukshetra-136 119, Email: roshandhiman_kuk@yahoo.co.in) : Structural and magnetic properties of zinc ferrite aluminates. Indian J pure appl Phys 2007, 45(3), 231-7.

Zinc ferrite aluminates ZnAl_xFe_2-xO₄ with composition (0 ≤ x ≤1) were synthesized at 1150°C using the usual ceramic method and studied by X-ray diffraction, magnetization and Mossbauer measurements. It is observed that lattice parameter decreases, with increasing Al concentration (x). Mossbauer absorption spectra of all the samples recorded at room temperature showed three hyperfine magnetic sextets and a single quadrupole doublet. The outer sextet is assigned to α- Fe₂O₃ crystalline phase, whereas inner two sextets refer to Fe³⁺ ions at octahedral (B) site and tetrahedral (A) site showing the formation of zinc ferrite aluminates phase. The hyperfine magnetic field was found to decrease with increasing AI concentration and has been explained on the basis of super transferred hyperfine field. The central doublet is partially dissociated forming ZnFeO₂ (delafossite) phase overlapping the main Mossbauer spectra measured at room temperature. The observed variations in saturation magnetization in all the samples have been explained on the basis of site distribution and the strength of the exchange interactions between the magnetic ions. On the basis of these observations, it is concluded that the present ferrite system exhibits a non-collinear magnetic structure with a very weak ferromagnetic character, which starts dominating further when zinc ferrite is diluted with non-magnetic A1³⁺ ions.

2 tables, 5 illus, 21 ref

023135   Razdan A (Astrophysical Sci Div, Bhabha Atomic Res Centre, Trombay, Mumbai-400 085, Email: Akrazdan@apsara.barc.gov.in) : On non-extensive nature of thermal conductivity. Pramana J Phys 2007, 68(1), 61-5.

Studies non-extensive nature of thermal conductivity. It is observed that there is similarity between non-extensive entropic index and fractal dimension obtained for the silica aerogel thermal conductivity data at low temperature.

1 illus, 23 ref

023134   Ramachandran C;Vidya M S;Balasubramanyam J (NO, Indian institute of Astrophysics, Koramangala, Bangalore-560 034, Email: gr@iiap.res.in) : Unified approach to photo- and electro-production of mesons with arbitrary spins. Pramana J Phys 2007, 68(1), 31-41.

A new approach to identify the independent amplitudes along with their partial wave multipole expansions, for photo- and electro-production is suggested, which is generally applicable to mesons with arbitrary spin-parity. These amplitudes facilitate direct identification of different resonance contributions.

1 table, 21 ref

023133   Priebe A;Meng F;Pucci A (Kirchhoff Insitute of Physics, Heidelberg University, , Im Neuenheimer Feld 227, D-69120 Heidelberg, Germany) : IR spectra of adsorbates on rough metal films. Asian J Phys 2006, 15(2), 239-45.

Metal films with thickness in the nanometer range are optically transparent. With IR transmittance spectroscopy the in ªplane film conductivity with its correlation to the film-growth process can be studied without electrical contacts and, on metal-island films, adsorbate vibrations can be observed because of surface enhanced IR absorption (SEIRA). Their analysis enables insight into the adsorbate-metal bonding and therefore gives information on the available adsorption sites and the crystalline facets correlated to. If the molecule keeps its symmetry, it is usually assumed that the same number of infrared active modes as for the free molecule appears in the adsorbate spectrum. However, as detected recently, depending on the film's roughness, the IR spectrum of adsorbate-vibration modes may be strongly modified because of their interaction with electronic excitations of the film. The atomic roughness of cold-condensed metal films produces additional infrared activity: strong infrared activity of Raman lines of centrosymmetric adsorbate molecules is observed in those cases where the adsorbate has states close to the Fermi level.

4 illus, 30 ref

023132   Prasad N;Daudi A A (Biocemistry Dep, Chemical Laboratory, Faculty of Basic Sciences & Huma, Rajendra Agriculture Univ, Pusa, Samastipur-848 125) : Temperature dependence of volumetric, acoustic parameters and molecular interactions in binary liquid mixtures. J pure appl Ultrasonics 2006, 28(1), 12-19.

The inter molecular free length, molar volume, available volume, free volume, molar sound velocity and degree of molecular interaction of N, N-dimethyl aniline+methylene chloride and N,N-dimethyl aniline+chloroform at 303.15K, 308.15K and 313.15K have been computed from ultrasonic velocity and density data and the results have been explained in terms of molecular interaction.

4 tables, 8 illus, 20 ref

023131   Patil S D;Raghavendra S C;Revansiddappa M; Narsimha P;*Ambika Prasad M V N (Materials Science Dep, Gulbarga Univ, Gulbarga-585 106, Email: prasad1_amb@rediffmail.com) : Synthesis, transport and dielectric property of polyaniline/Co₃O₄ composites. Bull Mater Sci 2007, 30(2), 89-92.

Conducting polyaniline/cobaltous oxide composites have been synthesized using in situ deposition technique by placing fine graded/cobaltous oxide in polymerization mixture of aniline. The a.c. conductivity and dielectric properties are studied by sandwiching the pellets of these composites between the. silver electrodes. It is observed that the values of conductivities increase up to 30 wt % of cobaltous oxide in polyaniline and decrease thereafter. Initial increment in conductivity is due to extended chain length of polyaniline where polarons possess sufficient energy to hop between favourable sites. Beyond 30 wt % of cobaltous oxide in polyaniline, blocking of charge carriers takes place reducing the conductivity values. It can be noted that the value of dielectric constant increases up to 10 wt % of cobaltous oxide. Thereafter, it decreases up to 30 wt % of cobaltous oxide and again increases up to 40 wt % of cobaltous oxide and decreases thereafter. The observed behaviour is attributed to the variation of a.c. conductivity. And it is observed that the dielectric loss increases up to 10 wt % of cobaltous oxide in polyaniline, decreases to a lower value of 20 wt % of cobaltous oxide and increases to 35 wt % and thereafter decreases. These values go in accordance with the values of dielectric constant. The results obtained for these composites are of greater scientific and technological importance.

6 illus, 11 ref

023130   Patil N S;Mallik A K (Mechanical Enng Dep, Indian Inst of Technol Kanpur, Kanpur-208 016, Email: akmallik@iitk.ac.in ) : Experimental investigation of the response of a harmonically excited hard Duffing oscillator. Pramana J Phys 2007, 68(1), 99-104.

A single degree-of-freedom torsional vibratory system, which constitutes a third-order dissipative dynamical system, has been fabricated as a mechanical analogue of hard Duffing equation with strong nonlinearity. The forced response of the system reveals complicated and chaotic motion at low frequency regime. Besides usual jump phenomenon, unpredictable jump phenomenon with two and three coexisting periodic attractors is also observed.

3 illus, 7 ref

023129   Patil L A;Mahanubhav M D (Physics P.G. Dep, Pratap College, Amalner-425 401, Email: lapresearch@rediffmail.com) : CdIn₂O₄ derived from CdIn₂S₄ prepared by flux method. Bull Mater Sci 2007, 30(2), 141-6.

Stoichiometric and nonstoichiometric powders of cadmium indium oxide were derived from calcination of cadmium indium sulphide prepared by flux method. The materials were confirmed by XRD. Thick films of above prepared powders were prepared on glass substrates using screen printing technique. The thick films were characterized by SEM and EDAX. The electrical conductivity of CdIn₂O₄ thick films was calculated. The gas sensing performance of Stoichiometric thick films of CdIn₂O₄ was tested for various gases. The films showed good response to LPG.

2 tables, 5 illus, 28 ref

023128   Parikh K D;Dave D J;Parekh B B;Joshi M J (Physics Dep, Saurashtra Univ, Rajkot-360 005, Email: mshilp24@rediffmail.com) : Thermal, FT-IR and SHG efficiency studies of L-arginine doped KDP crystals. Bull Mater Sci 2007, 30(2), 105-12.

Potassium dihydrogen phosphate (KDP) is a well known nonlinear optical (NLO) material with different applications. Since most of the amino acids exhibit NLO property, it is of interest to dope them in KDP. Amino acid L-arginine was doped in KDP. The doping of L-arginine was confirmed by FT-IR and paper chromatography. Thermogravimetry suggested that as the amount of doping increases the thermal stability decreases as well as the value of thermodynamic and kinetic parameters decreases. The second harmonic generation (SHG) efficiency of L-arginine doped KDP crystals was found to be increasing with doping concentration of L-arginine. The results discussed.

3 tables, 9 illus, 30 ref

023127   Pandey J D;Dey R;Soni N K;Mishra R K;Dwivedi D K (Chemistry Dep, Allahabad Univ, Allahabad-211 002, Email: jdpandey@rediffmail.com) : Modified flory theory and pseudo spinodal equation of state for the evaluation of isothermal compressibility, isentropic compressibility, internal pressure and pseudo gruneisen parameter of binary liquid mixtures at elevated pressure. J pure appl Ultrasonics 2006, 28(1), 20-8.

Flory's statistical theory has been extended for the computation of internal pressure, isentropic compressibility, isothermal compressibility and Pseudo Gruneisen parameter of binary mixture nitrobenzene+benzene at pressure up to 10 MPa and at too different temperatures (293.15K, 303.15K & 313.15K). For a comparative study of the isothermal compressibility of this system, equation of state based on the psuedo spinodal hypothesis developed by Baonza et al has also been utilized to deduce the isothermal compressibility of this mixture. The computed values of P_int, 98_T, 98_s and T have been compared with the experimental findings available in literature. Satisfactory agreement has been found between experimental and theoretical values.

4 tables, 34 ref

023126   Palafox M A;Tardajos G;Kim J J;Nielsen O F; Lodhi R;Rastogi V K (Departamento de Quimica-Fistea 1, Facultad de Clencias Quimicas, Universidad Complutense, Madrid-28040, Spain) : Predicting wavenumbers of vibrational aspectra, its use in spectroscopy. Asian J Phys 2006, 15(2), 281-5.

For the wavenumber calculations, many Quantum Chemical methods are available today, implemented in a large variety of programme packages. Gives a brief resume of the results obtained for some compounds of medium size, and the accuracy reached with them. It is concluded that the basis set has little influence, but the 6-31 G^* and 6-31 G^** have the most adequate cost-effective relationship.

3 tables, 13 ref

023125   Orlovich V A;Demidovich A A;Grabtchikov A S; Lisinetskii V A;Burakevich V N;Apanasevich P A;Danailov M B (I.B.I Stepanov Inst of Phys, , NASB, Independence Ave. 68, Minsk, 220062, Belarus) : Microchip lasers with interacavity Raman conversion - a new type of compact solid-state laser sources for spectroscopic applications. Asian J Phys 2006, 15(2), 231-8.

Recent results of experimental investigations of intracavity Raman conversion in microchip lasers are presented. Generation of Stokes pulses with duration as short as 50 ps and peak power up to 50 kW is shown. Multiline emission In the IR and 240-680 nm spectral range obtained by extracavity nonlinear conversion can be used in spectroscopy.

5 illus, 1 table, 18 ref

023124   Notingher I;Blaker J J;Maquet V;Hench L L; Boccaccini A R (Department of Materials and Centre for Tisue Engineering and Regenerat, Imperial College London, London SW7 2BP, UK) : Effect of polymer processing on the degradation of 45S5 bioglass <. Asian J Phys 2006, 15(2), 221-30.

The effect of the processing method on the in-vitro degradation of poly(lactic acid-co-glycolic acid) (PLGA) foam scaffolds and PLGA scaffolds filled with 45S5 Bioglass® particles was investigated by SEM and Raman spectroscopy. These materials have been developed with the aim of producing 3-D bioactive-biodegradable scaffolds for tissue engineering. SEM led to a qualitative understanding of degradation of the scaffolds by comparing the morphology of the porosity after degradation in PBS for different time periods. Raman spectra of neat PLGA and 45S5 Bioglass® (0.1 wt%)/PLGA foams produced by compression moulding (CM) and by thermally-induced phase separation (TIPS) processes were measured after degradation of the foams in phosphate buffered saline (PBS) for 4. 8 and 16 weeks. The degradation of the polymer scaffolds was indicated by the decrease in the magnitude of the Raman peaks corresponding to C-COO (872 cm^-1) and C=O (1766 cm^-1) stretching vibrations. It was found that the PLGA scaffolds produced by TIPS method degraded less that the CM foams. No influence on the chain scission was observed when the foams were filled with 45S5 Bioglass® particles. However, the results suggest that the buffering effect of the released alkaline ions by the bioactive glass particles could contribute to the breaking of the carbonyl groups in the TIPS sample but had less effect on the CM sample. It is likely that the thicker wall sections in the CM foams caused more hydrolytic degradation over the TIPS samples, due to water ingress, entrapment and autocatalysis.

5 illus, 1 table, 28 ref

023123   Narshima Reddy P;Ashok Kumar A;Jagadeswara Reddy K;Venkatramana Reddy S (Physics Dep, Microelectronics Div, Sri Venkateswara Univ, Tirupati-517 502, Email: dr_pnreddy@yahoo.com) : Data acquisition system using matlab for deep level transient spectroscopy studies. Indian J pure appl Phys 2007, 45(3), 204-9.

Microcontroller (AT89S8252) based data acquisition system has been developed for acquiring and processing the data from a home built deep level transient spectroscopy (DLTS)system. User friendly menu driven software has been developed in Matlab for selection of different DLTS measurement modes, data acquisition modes, channels (four channels) selection and number of data points on a single transient. It can be operated in two data acquisition modes namely scan mode and continuous mode. The scan mode is used to perform online analysis and continuous mode for offline data analysis. The developed software is also useful to operate the DLTS system in any one of the two operating modes namely boxcar mode or high resolution mode. The versatility of the data acquisition system is that the software developed can be used to obtain l-V characteristics using commercially available source meters. Also deals with the different wavelet decomposition methods for DLTS data acquisition and processing.

7 illus, 15 ref

023122   Manoj Kumar;Kumar M (Physics Dep, G.B. Pant University of Agriculture and Technology, Pantnagar-263 145, Uttaranchal, Email: munish_dixit@yahoo.com) : Melting temperatures of solids using the theory of equation of state. Indian J pure appl Phys 2007, 45(3), 256-7.

Simple method based on the theory of equation of state of solids is used to predict the melting temperatures of sixteen alkali halide solids. The results are compared with the experimental data. A good agreement between theory and experiment supports the validity of the model used. The method can also be used to determine B_o when the melting temperatures are known.

^ssc1 table, 13 ref

023121   Maniu D;Hiescu T;Ardelean I;Astilean S (Faculty of Physics, Babes-Bolyal University, Kogalniceanu 1, 400084 Cluj-Napoca, Romania, Email: dmaniu@phys.ubbcluj.ro) : Raman study of potassium borate glasses. Asian J Phys 2006, 15(2), 209-14.

The influence of vanadium and copper oxides content on the structure of potassium borate glasses was systematically studied by Raman spectroscopy by adding single oxide or both oxides. The addition of V₂O₅, CuO or V₂O₅, CuO in the 3B₂O₃.K₂O glass determines the breaking of the regular structure formed from boroxol rings and borate groups and the appearance of new structural groups like orthoborate groups and "loose" BO^-₄ tetrahedra. The number of non-bridging oxygen ions increases while vanadium and copper concentrations raise, thus the glass structure becomes more randomised. A small number of chain-type metaborate and pyroborate groups are also present in the studied glasses. Therefore. vanadium and/or copper ions act as network modifiers in potassium borate glasses.

4 illus, 12 ref

023120   Mangal R K;Vijay Y K (Physics Dep, Rajasthan Univ, Jaipur-302 004, Email: yk_vijay@sancharnet.in) : Annealing effects in In-Sb bilayer thin films. Bull Mater Sci 2007, 30(2), 117-21.

Thin Films of In-Sb having different thicknesses of antimony keeping constant thickness of indium was deposited by thermal evaporation method on ITO coated conducting glass substrates at room temperature and a pressure of 10^-5 torr. The samples were annealed for 1 h at 433 K at a pressure of 10^-5 torr. The optical transmission spectra of as deposited and annealed films have been carried out at room temperature. The variation in optical band gap with thickness was also observed. Rutherford back scattering and X-ray diffraction analysis confirms mixing of bilayer system. The transverse I-V characteristic shows mixing effect after annealing at 433 K for 1 h. Also confirms mixing of bilayer structure of semiconductor thin films.

3 tables, 10 illus, 21 ref

023119   Madhu U;Mukherjee N;Bandyopadhyay N R;Mondal A (School of Materials Science and Engineering, Begal Engineering and Science Univ, Shibpur, Howrah-711 103) : Properties of CdS and CdTe thin films deposited by an electrochemical technique. Indian J pure appl Phys 2007, 45(3), 226-30.

CdS and CdTe films have been deposited onto transparent conducting oxide (TCO) coated glass substrates using an electrochemical technique, where a cadmium foil was used as a sacrificial anode and no external bias being used during film deposition. The films were characterized using X-ray diffraction, scanning electron microscopy and optical absorption measurements. A CdS/CdTe thin film solar cell utilizing this deposition technique has been developed.

8 illus, 17 ref

023118   Khera S;Mathur S;Ahuja B L (Phys Dep, Univ Coll of Sci, M.L. Sukhadia Univ, Udaipur-313 001, Email: Blahuja@yahoo.com ) : Electronic structure of hafnium: a compton profile study. Pramana J Phys 2007, 68(1), 91-8.

Reports the first-ever isotropic Compton profile of hafnium measured at an intermediate resolution with 661.65 keV γ-radiation. To compare experimental data, the theoretical computations have also been carried out within the framework of pseudopotential using CRYSTAL03 code and the renormalized-free-atom (RFA) model. It is found that the present experimental profile is in better agreement with the RFA calculations if the outer electronic configuration is chosen as 5d^3.266s^0.8. The cohesive energy of Hf is also deduced from the experimental data and is compared with the available data.

1 illus, 2 tables, 30 ref

023117   Khadayate R S;Waghulde R B;Wankhede M G;Sali J V;Patil P P (Physics Dep, North Maharashtra Univ, Jalgaon-425 001, Email: rskhadayate@yahoo.com) : Ethanol vapour sensing properties of screen printed WO₃ thick films. Bull Mater Sci 2007, 30(2), 129-33.

Presents ethanol vapour sensing properties of WO₃ thick films. The WO₃ thick films were prepared by standard screen-printing method. These films were characterized by X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM). The ethanol vapour sensing properties of these thick films were investigated at different operating temperatures and ethanol vapour concentrations. The WO₃ thick films exhibit excellent ethanol vapour sensing properties with a maximum sensitivity of <126>1424.6% at 400°C in air atmosphere with fast response and recovery time.

5 illus, 15 ref