006312   Dhaduk B;Patel C;Parsania P H (Polymer Chemistry Div, Chemistry Dep, Saurashtra Univ, Rajkot-360 005, Email: phparsania22@gmail.com) : Crystallographic analysis of 1,1'-bis (3-methyl-4-hydroxyphenyl) cyclohexane. Indian J pure appl Phys 2016, 54(5), 346-50.

The crystal structure of 1,1'-bis(3-methyl-4-hydroxyphenyl) cyclohexane has been determined by X-ray crystallographic technique. The compound crystallized into monoclinic crystal lattice having space group P2₁/c with unit cell parameters, a = 15.023(2) Angstrum, b = 9.924(2) Angstrum, c = 11.620(2) Angstrum, α = γ = 900, β = 112.41(1), V = 1601.5(5) Angstrum^{3 and Z = 4. Other parameters, such as atomic coordinates, bond lengths, bond angles, torsion angles and geometry of intermolecular interactions are also determined.}

4 illus, 4 tables, 21 ref

006311   Binitha M P;Pradyumnan P P (Physics Dep, Government College Kodanchery, Kodanchery-673 580, Email: drpradyumnan@gmail.com) : Spectroscopic, thermal and dielectric studies on copper maleate monohydrate single crystals. Indian J pure appl Phys 2016, 54(7), 453-7.

Copper maleate monohydrate (CMM) crystals grown in gel medium have been characterized by XRD, FTIR and FT-Raman spectral studies. The thermal behavior of the crystals has been investigated by thermo gravimetric and differential thermal analyses. The results indicate that the grown crystals are thermally stable up to 100 °C. The decomposition process occurs in two stages until copper oxide is formed, which is confirmed by XRD analysis. The variations of dielectric constant and ac conductivity of the crystals have been studied as a function of frequency at different temperatures.

10 illus, 1 table, 19 ref

006310   Bhavani G;Ganesan S (Physics Dep, Jansons Institute of Technology, Karumathampatti, Coimbatore-641 659, Email: bhavaneeg@gmail.com) : Structural and optical study of yttrium oxide co-doped with bismuth and zinc prepared by sol-gel method. Indian J pure appl Phys 2016, 54(5), 307-12.

Bismuth and zinc co-doped Y₂O₃ samples are synthesized by sol-gel method using ammonium hydroxide as a precipitating agent. Structural analysis is done by XRD, SEM- EDAX and the optical properties are analysed by FTIR, UV-Vis absorption studies and photoluminescence (PL) studies. UV-Vis absorption studies show absorption only around 340 nm whereas PL shows peaks around 401 nm, 680 nm and 1020 nm for Y₂O₃ co-doped with bismuth and zinc. The PL spectrum shows emission in violet region (401 nm) due to zinc dopant and red and NIR region (680 nm and 1020 nm) due to the bismuth dopant. This is a new material which can effectively work as an efficient and cheap red phosphor.

6 illus, 38 ref

006309   Bhakuni G;Bisht S (Physics Dep, Kumaun Univ, Nainital-263 002) : Nonrelativistic scattering of an electric charge in the radial field of a fixed dyon. Int J latest Technol Engng Mgmt appl Sci 2016, 5(1), 30-3.

Using one scalar potential and one vector potential and interpreting the vector potential suitably for the radial magnetic field the nonrelativistic problem of scattering of an electric charge by a fixed dyon has been studied and scattering solutions and cross section have been obtained.

16 ref

006308   Bajaj N S;Omanwar S K (Physics Dep, Toshniwal Arts, Commerce and Science College, Sengoan-431 542, Email: nsb.0208@yahoo.com) : Studies on optical properties of LiCaBO₃: Tb<. Indian J pure appl Phys 2016, 54(7), 458-62.

The green emitting phosphor LiCaBO₃:Tb^{3+ has been synthesized by easy, time saving, cost effective modified method of solution combustion synthesis at comparatively lower temperature using urea as fuel. X-ray power diffraction (XRD) analysis confirms the formation of the said phosphor. Photoluminescence measurements show that the phosphor has exhibited emission peak with good intensity at 547 nm, corresponding to 5D₄-7F₅ (547 nm) green emission and weak 5D₄-7F₅ (486 nm) blue emission. The excitation spectra monitored at 547 nm show broad band from 250 to 300 nm ascribed to spin-allowed 4f8-4f75d transitions of Tb3+. Also, no charge-transfer (CT) transition related to Tb3+-O2- has been observed. For the excitation wavelength of 240 nm the emission intensity increases initially with the increase of Tb3+ concentration and reaches to the maximum at x = 0.005. The concentration quenching observed after that is mainly due to quadrupole-quadrupole interaction. The as synthesized phosphor LiCaBO₃:Tb3+ by this method shows CIE colour coordinates of (0.28, 0.71) with good intensity.}

7 illus, 2 tables, 17 ref

006307   Babu J C;Mouli V C (Physics Dep, Government City College, Hyderabad-500 002, Email: drjcbabu33@gmail.com) : Spectroscopic studies of Cu<. Indian J pure appl Phys 2016, 54(5), 339-45.

Differential scanning calorimetry (DSC), electron spin resonance (ESR), Raman, infrared (IR) and optical absorption studies on 10Na₂O-xNb₂O₅-(89-x)TeO₂-1CuO glasses (where x = 0, 5, 10, 15 and 20 mol%) containing Cu^{2+ spin probe have been carried out. Glass transition temperature (T_g) and thermal stability of glass samples have been estimated from the DSC measurements and it has been found that both increase with increasing the Nb₂O₅ content. From Raman and IR spectra, it is clear that present glass system consists of structural units of TeO₃ (tp) and TeO₄ (tbp) and NbO₆ octahedra. Also, TeO₄ units convert into TeO₃ units with change in Nb₂O₅ content. The hyperfine splittings in the parallel features of ESR spectra of Cu2+ are recorded for all compositions. ESR results show that g_|| <62> g_⊥ indicating that the Cu2+ ion is in tetragonal distorted octahedral site and its ground state is d_x2-y2. There is considerable variation in Hamiltonian parameters for the different compositions. The observed optical absorption peak of Cu2+ is found to be maximum at 780 nm for 10 mol% of Nb₂O₅ content. Bonding parameters and % bonding symmetry are calculated from both optical and ESR data changing with increasing Nb₂O₅ content.}

6 illus, 8 tables, 27 ref

006306   Azimi M;Riazi R (Faculty of New Sciences and Technologies, Tehran Univ, Trhran, Iran, Email: ro_riazi@ut.ac.ir) : Analytical simulation of mixed convection between two parallel plates in presence of time dependent magnetic field. Indian J pure appl Phys 2016, 54(5), 327-32.

Heat transfer enhancement in various energy systems is vital because of the increase in energy prices. In recent years, nanofluids technology is proposed and studied by some researchers experimentally or numerically to control heat transfer in a process. In this paper, an unsteady incompressible three-dimensional mixed convection rotating flow of viscous fluid between two infinite vertical plane walls is investigated analytically using Galerkin optimal homotopy asymptotic method (GOHAM). We also consider the viscous dissipation effects. Such a consideration is significant, because the viscous dissipation effects (the generation of heat due to friction caused by shear in the flow) are important when the fluid is largely viscous or flowing at a high speed. The effects of the emerging parameters on the flow and heat transfer characteristics are studied and examined.

7 illus, 1 table, 20 ref

005247   Prasad R (Applied Mechanics Dep, Indian Institute of Technology Delhi Hauz Khas, New Delhi-110 106, Email: rajesh@am.iitd.ac.in) : Errors in the Feynman lectures on physics symmetry and crystals. Resonance 2016, 21(5), 429-37.

Authors discuss some errors in The Feynman Lectures on Physics related to the concept of symmetry. We also suggest a possible correction to Fig. 1.4 of Vol. I. The discussion may be useful for students of crystallography, solid state physics and solid state chemistry.

5 illus, 4 ref

005246   Panda D K;Banerjee D;Goyal S K;Patel A R; Shukla A D (Planetary Sciences and Exploration Group, Physical Research Laboratory, Ahmedabad-380 009, Email: deba@ppl.res.in) : Development of a cerium-doped lanthanum bromide gamma-ray spectrometer for planetary missions and feasibility studies for determination of elemental abundances of radioactive elements (Th, K and U). Curr Sci 2016, 110(11), 2135-8.

Author present the development of a cerium-doped lanthanum bromide (LaBr3: Ce) gamma-ray spectrometer (GRS) with the primary objective of determining the abundance and distribution of Th, U, K, and other major elements, including Fe on the entire planetary surface by measuring gamma-ray signals produced by radioactive decay, neutron inelastic scattering and neutron capture reactions in the energy region 0.03-8 MeV. The energy resolution of the LaBr3: Ce GRS developed in-house using front-end and processing electronics at 511 and 1274 keV is estimated to be 4.1% and 2.5% respectively. The intrinsic activity count rate for our 3" x 3" LaBr3: Ce GRS is -61 counts s<^>-1 (i.e. -0.18 counts s<^>-1 cm<^>-3) for the <^>40K energy window (1400-1520 keV) and <126>3.4 counts s<^>-1 for the <^>232Th (2550-2700 keV) energy window. Although this large intrinsic activity of the LaBr3: Ce crystal inhibits estimation of the concentrations of Th and K, our attempts using a Nal(Tl) GRS (with electronics developed in-house) were more successful. The Th concentration of US-110 was estimated to be <126>11.4 ppm and is within 14% of the 13.2 ppm value determined using a HPGe GRS. The K concentration of US-110 was estimated to be 0.87% and is within <126>10% of the 0.78% value determined independently using a HPGe GRS.

5 illus, 1 table, 6 ref

005245   Ghosh A;Dey U (Aerospace Engineering and Applied Mechanics Dep, Indian Institute of Engineering Science & Technology, Shibpur P.O. Botanic Garden, Howrah-711 103, Email: amitabha@iitk.ac.in) : Paradox of Newtonian gravitation and Laplace's solution. Resonance 2016, 21(5), 447-52.

Newton's theory of gravitation solved many problems of celestial mechanics but led to some major problems, one of which was that it gave rise to a serious paradox discussed in this article. The paradox has a number of manifestations one of which is presented here. It should be remembered that the root cause of all these paradoxes is fundamentally the same. Laplace attempted an ad hoc solution. However, it could not be mathematically demonstrated that his proposal solves the difficulty. In this article, it is shown that his suggestion removes the problem. A physical phenomenon that can justify Laplace's suggestion is also mentioned briefly. This article also poses an interesting mathematical problem that can be attempted by interested readers. The computational solution is presented here.

1 illus, 3 tables, 2 ref

005244   Dasannacharya B A (NO, , No. 4, Beach Resort CHS, Sector 10-A, Plot 1, Vashi, Navi Mumbai-400 703, Email: adasannacharya@gmail.com) : Some contributions to neutron scattering in India and Asia-oceania region: 1958-2012. Curr Sci 2016, 110(11), 2067-78.

National, regional and international cooperation is well known nowadays when it comes to building and using major scientific facilities like nuclear reactors, particle accelerators, space exploration, etc. It was not so when I started my research career in 1958 at Atomic Energy Establishment Trombay (AEET), now renamed Bhabha Atomic Research Centre (BARC). Asia-Oceania Neutron Scattering Association (AONSA) was established some years ago in recognition of this need in the region specified in its name. In the present article I shall deal with some aspects of my contributions to the growth of neutron scattering techniques and science, and highlight how cooperation among various bodies has helped in the growth of science based on neutron scattering.

26 illus, 38 ref

004244   Vishwam T;Parvateesam K;Babu S;Sastry S S; Murthy V R K (Physics Dep, Gitam Univ-Hyderabad campus, Rudraram village, Patancheru-502 329, Email: vishwam@gutam.in) : Study of excess dielectric and thermodynamic parameters of hydrogen bonded system: isobutanol and ethyl benzoate. Indian J pure appl Phys 2016, 54(9), 597-611.

Complex dielectric permittivity of polar systems of isobutanol and ethyl benzoate for various mole fractions at different temperatures has been studied by using the open-ended coaxial probe technique method in the microwave frequency range from 20 MHz to 20 GHz. The dipole moment, excess dipole moment, Bruggemart parameter, excess Helmholtz energy, excess permittivity, excess inverse relaxation time, excess thermodynamic values are calculated using experimental results. The optimized geometry, harmonic vibrational wave numbers and dipole moments of pure and equimolar binary mixtures have been calculated theoretically from HF, B3LYP with 6-311G and 6-311G+ basis sets by using Gaussian-03 software. Conformational analysis of the formation of hydrogen bond between isobutanol and ethyl benzoate is supported by the FT-IR, 'NMR and molecular polarizability calculations. The calculated wave numbers and dipole moments agree well with the experimental values. Further, the correlations among the parameters have been discussed in detail.

13 illus, 7 tables, 68 ref

004243   Vishwakarma S R (Physics & Electronics Dep, Dr R M L Awadh Univ, Faizabad-224 001, Email: srvfzb@rediffmail.com) : Electrical and optical property on n-type InSb thin films. Indian J pure appl Phys 2016, 54(9), 557-61.

The n-type indium antimonide thin films of the thickness 900 nm have been fabricated by electron beam evaporation technique on ultrasonically cleaned glass substrates at different temperatures (298 K-473 K) using optimized source material. The electrical and optical properties of these films have been studied and optimized the film deposition temperature. The electrical resistivity decreases (1.50-0.25)x10^{-3 ohm.cm with increase of temperature up to 398 K. The Hall Effect measurement indicates that the films are n-type semiconductor having carrier concentration (0.100.040)xl018 cm-3 and mobility (3.03-53.20)xl04 cm2/Vs. The type of semiconductivity has also been confirmed by TEP measurement. The direct band gap has been calculated by Fourier Transform Infrared (FTIR) transmission spectra recorded at room temperature. The direct band decreases from 0.195 to 0.180 eV with increase of substrate temperatures (298 K-473 K). The carrier concentration 0.040xl018cm-3. Hall mobility 53.20x104cm2/Vs, electrical resistivity 0.25 x10-3 ohm.cm and direct band gap 0.18 eV have been observed for n-InSb film of 900 nm thick deposited at 398 K.}

6 illus, 24 ref

004242   Tripathi R K;Panwar O S;Chockalingam S (Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Div, CSIR-National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110 012, Email: ospanwar@mail.nplindia.ernet.in) : Nanoindentation study on nitrogenated tetrahedral amorphous carbon thin films with ultra low load. Indian J pure appl Phys 2016, 54(9), 543-50.

This paper reports the improved nanomechanical properties of as grown and nitrogen incorporated tetrahedral amorphous carbon (ta-C, ta-C: N) films deposited by S-bend filtered cathodic vacuum arc (FCVA) technique using nanoindentation. The effect of varying amount of nitrogen incorporation on the nanomechanical properties of ta-C films deposited at a high substrate bias of -300 V at ultra low load of 1.4 mN has been studied. It has been found that the nitrogenation has improved the mechanical properties of ta-C films. The hardness H of 27.8 GPa with improvement of <126>30% and plastic index parameter (ratio of H to elastic modulus E) (HIE) of 0.091 with improvement of <126> 25% has been obtained for ta-C: N films deposited at a nitrogen partial pressure of 1.9x10^{-2 Pa. Improved H and H/E of ta-C: N films may be due to the better ionization and incorporation of nitrogen in a carbon matrix at the high negative substrate bias used in the deposition of FCVA technique.}

6 illus, 48 ref

004241   Sengupta D P (School of Natural and Engineering Sciences, National Institute of Advanced Studies, Indian Institut of Science Campus, Bengaluru-560 012, Email: sengupta.dp@gmail.com) : Brief history of time, time-keeping and the consequences of adjusting Indian standard time. Sci Cult 2016, 82(1-2), 12-18.

This paper briefly explores the history of Time, when people became aware of breaking of a day, arid its duration, descending of darkness and duration of night, dividing day and night into parts and keeping track of time. The ushering in of standard time and time zones and finally proposing an adjustment of Indian Standard Time and its likely consequences.

11 illus, 4 ref

004240   Sarma S S;Verma S;Rajkumar (Electronics & Communication Engineering Dep, Assam Don Bosco Univ, Guwahati-781 017, Email: raj_csio@yahoo.com) : Holographic diffuser for multichannes restricted display. Indian J pure appl Phys 2016, 54(8), 495-9.

Diffusers play an important role in modern days display technology. Holographic diffusers offer effective control on various parameters of the diffused light like diffusion angle, uniformity of light etc. Present work reports a procedure for realization of a holographic diffuser through which multichannel restricted view display is achieved such that information can be conveyed to and viewed from multiple selective viewpoints only. Such type of diffusers will be helpful in enhancing security feature of the displayed information by enabling only authenticated persons to have access to the information. Fabrication process of the holographic diffuser is described and experimental results are discussed.

5 illus, 20 ref

004239   Salehi N (Basic Sciences Dep, Shahrood Branch, Islamic Azaf Univ, Shahroon, Iran, Email: salehi@shahroodut.ac.in ) : Baryon masses in a nonrelativistic model with the quantum isotonic oscillator potential. Indian J pure appl Phys 2016, 54(11), 733-8.

The nonrelativistic quark model and a new baryon mass formula have been applied to study the baryon octet and decuplet masses. To describe the quark-quark interacting forces inside baryons, a suitable phenomenological form of the potential and quantum isotonic oscillator potential have been proposed. A comparison between calculations reported in this study and the available experimental data is investigated. The description of the spectrum shows that the position of the Roper resonances of the nucleon, the ground states and the excited multiplets up to three GeV are in general well reproduced.

2 tables, 35 ref

004238   Sahu K;Murty V V S (Physics Dep, Government Holkar Science College, Indore-452 017, Email: kirtisahu4star4@gmail.com) : Novel sol-gel method of synthesis of pure and aluminum doped TiO₂ nanoparticles. Indian J pure appl Phys 2016, 54(8), 485-8.

Pure and doped titanium dioxide (TiO₂) nano particles have been prepared using acid tailored novel sol-gel method based on the use of new chemicals using different doping concentration of metal aluminum (Al) at annealing temperature of 450 °C. Powder XRD and UV-Vis have been used to investigate the effect of Al doping in pure TiO₂. Particle size analysis using X-ray line broadening shows marginally increasing trend with increasing Al impurity. Results show that all samples prepared by this method having particle size in the range of 11 nm to 23.9 nm. UV-Vis analysis indicates decrease in energy band gap due to Al doping which means there is a shift in the solar spectrum towards the lower wavelength region in case of doped TiO₂ and hence absorption is increased as compared to pure TiO₂. Metal doping of Al enhances electrical conductivity due to plasmonic effect and improves optical transparency of TiO₂ semiconductor at a low cost. The value of band gap for pure TiO₂ is 3.1 eV and decreases to 2.8 eV for 0.03 mole % of Al in Pure TiO₂. Versatile, cheap and easy novel method has been reported for preparation of pure and doped TiO₂ nano particles, which can be used for making photo anode for solar cells.

2 illus, 1 table, 26 ref

004237   Rawat A K;Rawat A;Upadhyay T C (Physics Dep, H N B Garhwal Univ, Srinagar, Garhwal-246 174, Email: arvindsgfi@gmail.com) : Temperature dependence of ferroelectric mode frequency, dielectric constant and loss tangent in PbHAsO₄ crystal. Indian J pure appl Phys 2016, 54(11), 713-19.

The ferroelectric transition of PbHAsO₄ crystal has been studied using two sublattice pseudospin-lattice coupled mode model with addition of third-order and fourth-order phonon anharmonic interactions terms. With the help of double-time ihermal Green's function method, expressions for ferroelectric mode frequency, dielectric constant and dielectric loss tangent have been derived. By fitting model values of physical quantities, temperature dependence of ferroelectric mode frequency, dielectric constant and loss tangent have been numerically calculated for PbHAsO₄ crystal. Theoretical results have been compared with correlated experimental results of Arend et al.^{19. The results obtained in present study are in good agreement with experimental results.}

3 illus, 6 tables, 19 ref

004236   Ravicnahdran C;Arumugam S (P G & Research Dep of Physics, A A Government Arts College, Villupuram-605 602, Email: ravichandran_Ganesan@yahoo.com) : Ultrasonic relaxation studies in some amino acids. Indian J pure appl Phys 2016, 54(9), 589-96.

Ultrasonic relaxation studies have been carried out in aqueous solutions of some amino acids namely 1-arginine, 1-isoleucine and 1-norvaline in the frequency range of 2 to 30 MHz and in the pH range 5.5 to 11.5. These studies have been carried out at a fixed amino acid concentration of 0.05 molar and at a fixed temperature of 303.15 K. The excess ultrasonic absorption obtained in aqueous solutions of amino acids has been explained in terms of proton-transfer reactions occurring in the amino acid solutions. The excess absorption observed around neutral pH has been attributed to ionic hydration. The rate constant for the forward and backward reactions occurring in these amino acid solutions and the volume change taking place due to these reactions have been estimated and reported in this article.

7 illus, 2 tables, 27 ref

004235   Ozdemir H;Yurtseven H (Physics Dep, Middle East Technical Univ, 06531 Ankara, Turkey, Email: hamit@metu.edu.tr) : Temperature and pressure dependence of the Raman frequency shifts in anthracene. Indian J pure appl Phys 2016, 54(8), 489-94.

In this study, the Raman frequency shifts of phonons and vibrons of crystalline anthracene as functions of temperature (at zero pressure) and pressure (at ambient temperature) have been calculated using the experimental volume data from the literature. This calculation is performed for six phonons and nine vibrons through the mode Gruneisen parameters which have been determined from the Raman frequency and volume data at various pressures. Our predicted Raman frequencies of the phonon modes decrease with increasing temperature (zero pressure) linearly, whereas they increase with increasing pressure (ambient temperature) nonlinearly, as observed experimentally for anthracene. For vibrons, we find that the Raman frequencies are almost independent of temperature and pressure in this crystalline system.

4 illus, 4 tables, 19 ref

004234   Murila M;Ayodo Y K;Khanna K M;Miller E S; Indumuli J (Physics Dep, Masinde Muliro Univ, Box 190 Kakamega, Kenya, Email: murilangu@gmail.com) : Determination of energy gap directly from phase shift for nuclear systems with large neutron excess. Indian J pure appl Phys 2016, 54(8), 507-10.

Considering S₀ pairing in infinite neutron matter and nuclear matter, and knowing the fact that in the lowest order approximation, the pairing interaction has been taken to be the bare nucleon-nucleon interaction in the So channel, the energy gap has been determined directly from the So phase shifts. The values of energy gaps have been found to increase rapidly for low values of phase shifts, up to around 16°, and it is roughly constant with a value approximately equal to 1.08 MeV for phase shifts^{1 greater than 16°.}

1 illus, 15 ref

004233   Mohamed M;Kada H;Wahid B A (Electrotechnical Engineering Laboratory, Tahar Moulay of Saida Univ, Algeria, Email: mankourmohamed312@yahoo.fr) : Modeling of glow discharge in dielectric barrier. Indian J pure appl Phys 2016, 54(11), 701-12.

Numerical calculations of spatio-temporal characteristics of the homogeneous dielectric barrier discharge (DBD) in pure helium have been performed by means of a one-dimensional fluid model. The influence of the elementary processes on the discharge behavior has been studied by variation of the corresponding rate constants. The simulation and the analytical interpretation have been carried out for two basic modes of the homogeneous barrier discharge. The specificity of the glow discharge is the development of a cathode region and a positive column during the breakdown, as well as the presence of quasi-neutral plasma in subsequent phases. The positive column occurs because the shielding of the external field by the plasma is not instantaneous. The dependence of the discharge behavior on the external parameters, such as, the amplitude and frequency of the applied voltage, discharge gap width and thickness of dielectric barriers has been analyzed.

19 illus, 40 ref

004232   Mitra M S;Sarkar P K;Bandyopadhyay T;Sharma D N (HP Unit (HPD, BARC), Variable Energy Cyclotron Centre, 1/AFm Bidhnnagar, Kolkata-700 064, Email: mausumi@vecc.gov.in) : Empirical relation between energy and angular deviation of muons transmitted through thick slabs. Indian J pure appl Phys 2016, 54(11), 739-43.

This is to facilitate detection of materials of high atomic number buried inside materials of low atomic number using cosmic ray muons, Monte Carlo simulations have been carried out and an empirical relation has been developed to correlate energy with the most probable angular deviation of transported muons through slabs of different materials. This empirical relation describes the correlation between the energy distribution and the distribution of angular deviation of muons passing through slabs of different materials and of different thickness, and is expected to be useful in the field of cosmic ray muon radiography.

7 illus, 1 table, 10 ref

004231   Khalid S;Murtaza G;Jan S U;Ullah N;Yar A (Physics Dep, Hazara Univ Mansehra, Pakistan, Email: murtaza@icp.edu.pk) : Structural and electronic properties of Y_1-xGe_xTe (Y=Sn,Pb) by DFT. Indian J pure appl Phys 2016, 54(11), 694-700.

The structural, electronic, and chemical bonding properties of the Ge doped PbTe and SnTe in the rock salt phase have been calculated by full potential linearized augmented plane wave method within density functional theory. Generalized gradient approximation of Wu and Cohen has been utilized for calculating these properties. With doping of Ge in Pb_{1- x}Ge_xTe and Sn_1-xGe_xTe, the lattice constant reduces linearly as the concentration increases. Also, it is observed that electronic properties of these compounds are affected by varying concentration of doping Ge. The band gap of corresponding compounds varies with respect to the composition, so the electronic properties alter as doping increases. The alloys have direct band gap which varies in the range 0 to 0.19 eV. The alloys Pbi_1-xGe_xTe and Sn_1-xSn_xTe show covalent bonding nature which enhances by increasing the Ge concentration. As the physical properties vary widely with doping therefore the resulted materials can be used in thermoelectric, optical storage devices, Infrared detectors, Bragg's reflectors and optical devices working in lower frequency regime.

9 illus, 2 tables, 26 ref

004230   Kannagaraj M;Kokila I P;Subbulakshmi N; Sathish Kumar P;Rajesh A L;Arumugam S (NO, Centre for High Pressure Research, School of Physics, Bharathidasan Un, Tiruchirappalli-620 024, Email: sarumugam1963@yahoo.com) : Systematic investigation of structural, optical and magnetic properties of pristine BaFe₂O₄, Mg and Mg, Cs co-doped in BaFe_2-xMg_xO₄ and Ba_1-xCs_xFe_2-yMg_yO₄ spinel nanoferrites. Indian J pure appl Phys 2016, 54(8), 500-6.

The oxygen annealed barium nanoferrites have been synthesized by the chemical co-precipitation technique integrated with microwave treatment. The effects of doping on structural, optical and magnetic properties have been studied in detail. Powder XRD of the Mg doped and Mg, Cs co-doped BaFe₂O₄ shows large variation in the crystallite size especially due to the impact of alkali (Mg) andjalkali earth metal (Cs) doping in octahedral and tetrahedral sites of the orthorhombic spinel structure. The appropriate atomic compositions and functional groups have been confirmed by the EDX and FTIR spectrums. The structural transformation of substantial nanoparticles to marginal nanorods explicit in the SEM micrograph and the evolution of high band gap have been obtained from the UV-Vis spectra. The magnetic hysteresis in the field range of ±1.5 T at room temperature has revealed the hard ferromagnetic characteristics with large coercivity and remanence for Mg, Cs co-doped BaFe₂O₄ than other spinel systems.

5 illus, 3 tables, 25 ref

004229   Horng J W;Chiu W Y (Electronic Engineering Dep, Chung Yuan Christian Univ, Chung-Li, 32023, Email: jwhorng@cycu.edu.tw) : High input impedance voltage-mode biquad with one input and five outputs employing four CCII ICs. Indian J pure appl Phys 2016, 54(9), 577-82.

A new second-generation current conveyor (CCII)-based voltage-mode biquadratic filter with one input terminal and five output terminals has been presented. The proposed circuit uses four plus-type CCIIs, two grounded capacitors and five resistors and it is suitable for implementation with the now available integrated circuit (IC). The proposed circuit can realize all the standard filter functions; high-pass, band-pass, low-pass, notch and all-pass, simultaneously, without changing the passive elements. The proposed circuit enjoys the features of high input impedance, orthogonal controllable of resonance angular frequency and quality factor, using only grounded capacitors as well as low active and passive sensitivities. The feasibility of the proposed configuration has been demonstrated by practical results.

5 illus, 1 table, 39 ref

004228   Gidena A;Bhardwaj M K (Physics Dep, College of Natural and Computational Sciences, Mekelle Univ, Ethiopia) : Measurement of indoor radon concentration in some dwellings of Adwa, Ethiopia. Int J Sci Nat 2016, 7(2), 364-9.

An indoor radon measurement was carried out in different dwellings in Adwa using Passive techniques Solid-state nuclear track detectors (LR-115 type II plastic track detectors) in a bare mode. The detectors were properly arranged in 12 houses and collected after an exposure time of 47days. The detectors were etched using 2.5N NaOH solution at 60°C for 75 minutes. The films were studied under transmitted light microscope and counted the tracks for each film. The results show that, the indoor radon concentration in the dwellings varied from 14.22 Bq m^{-3 to 161.74 Bq m-3 with mean value of 56.72 Bq m-3 and standard deviation of 40.43. The values of indoor radon concentrations in the dwellings are below the lower limits of reference level (200 Bq m-3) as recommended by (ICRP, 2009) and (WHO, 2009), but 8.3% of them are higher than the reference level of 148 Bq m-3 as recommended by (EPA, 1987). The potential alpha energy concentration in the dwellings varied from 1.53 mWL to 17.49 mWL with mean value of 6.13 mWL and standard deviation of 4.37. All values of potential alpha energy concentration in the dwellings are lower than the recommended value of (53.33 mWL) by (UNSCEAR, 1993). The inhalation doses in the dwellings varied from 0.13 mSv/Y to 1.46mSv/Y with mean value of 0.51mSv/Y and standard deviation of 0.36. In all the dwellings the inhalation dose is found less than the lower limit of the reference level (3 mSv/y) recommended by (ICRP, 1993). The mean radon concentration in the ground and first floor rooms were 59.82 Bqm-3and 50.52 Bq m-3 respectively and the mean radon concentrations in living rooms, offices and stores were 27.82 Bq m-3, 62.87 Bq m-3 and 108.39 Bq m-3respectively. Risk of lung cancer related to radon is expected to be negligible in these dwellings; therefore, living in these dwellings are comparatively safe.}

24 ref

004227   Ghonge S;Banerjee S (Physics Dep, Birla Institute of Technology and Science, Pilani, Hyderabad-500 078, Email: souri@hyderabad.bits-pilani.ac.in) : Dependence of shape and geometry of microelectrodes in manipulating polarisable particle like DNA through electro-kinetic effects. Def Sci J 2016, 66(4), 307-15.

Recently electro-kinetics, namely AC electro-osmosis and dielectrophoresis have been judiciously utilised to manipulate movement of polarisable particles like DNA suspended in aqueous solution and placed between electrically fed microelectrodes. Researchers around the globe have tried to fabricate electrodes of different geometries to understand how electric field owing to sharpness of the electrodes has influenced the aforementioned electro-kinetic properties. Presented a chronological development in design of patterned electrodes used to align and trap DNA molecules in and around the electrodes. We have examined the pros and the cons of such geometry of the set of the micro-electrodes and also tried to provide a solution in terms of shape and sharpness of the electrode that would facilitate DNA molecules to bridge between the electrodes for further application of conducting DNA as molecular wire.

12 illus, 27 ref

004226   Datta P K (Kalpana Chawla Centre for Space & Nano Science, Presidency College, Kolkata-700 073, Email: dattapradip@gmail.com) : International year of light and light-based technologies. Sci Cult 2016, 82(1-2), 29-33.

The year 2015 has been declared by the General Assembly of the UNO as the International Year of Light and Light-based Technologies as these have important roles in the lives of the people in different ways and the year coincides with the anniversaries of a series of important milestones in the history of the science of light. In this article the applications of light in our daily life have been discussed. History of light has also been discussed briefly.

7 ref

004225   Das S;Jana R N;Ghosh S K (Mathematics Dep, Gour Banga Univ, Malda-732 103, Email: jana261171@yahoo.co.in) : Hall effects unsteady MHD natural convective flow past an impulsively moving plate with ramped temperature and concentration. Indian J pure appl Phys 2016, 54(8), 517-34.

This paper deals with the study of an unsteady magnetohydrodynamic natural convective flow of a viscous incompressible electrically conducting fluid past an impulsively moving infinite vertical plate with ramped temperature and mass concentration taken into account the Hall effects. A uniform magnetic field is applied transversely to the direction of the flow. The flow consideration is subjected to small magnetic Reynolds number. Induced magnetic field is absent. The Rosseland approximation is used to describe the radiative heat flux in the energy equation. Analytical solution of the governing equations has been obtained by employing the Laplace transform technique. The influences of the pertinent parameters on the velocity field, temperature distribution, mass concentration in fluid, shear stress and rate of heat and mass transfer are discussed with the help of graphs. Hall current is found to elevate the fluid velocity components. It is observed that significant difference can be observed between the velocity profiles due to ramped and isothermal boundary conditions.

20 illus, 44 ref

004224   Chandra A (Applied Physics Dep, Shri Shankaracharya Institute of Professional Management & Technology, Raipur-492 015, Email: chandrassi@gmail.com) : Preparation and characterization of hot-pressed solid polymer electrolytes: (1-x)PEO: xNaBr. Indian J pure appl Phys 2016, 54(9), 583-8.

Preparation and ionic transport characterizations of a new Na^{+ ion conducting hot-pressed solid polymer electrolytes (SPEs) (1-x)PEO: xNaBr, where 0 <60> x <60> 50 in wt%, have been reported. SPE films have been prepared using a hot-press technique in place of the traditional solution cast method. Two orders of magnitude of the conductivity enhancement achieved in SPE film composition (70PEO:30NaBr) at room temperature. Polymer-salt complexations and thermal behavior of present SPEs have been explained with the help of X-ray diffraction (XRD), differential scanning calorimetric (DSC), thermogrevimetric analysis (TGA) and scanning electron microscopy (SEM) technique. The Na+ ion conduction in the present SPEs has been discussed on the basis of experimental measurements on its ionic conductivity σ, ionic mobility μ. and ionic transference number t_ion at room temperature. Temperature dependent ionic conductivity measurement has also been carried out to calculate the activation energy E_a.}

9 illus, 3 tables, 25 ref

004223   Balaprakash V;Gowrisankar P;Sudha S (NO, Hindusthan College of Arts and Science, Coimbatore-641 028, Email: km.balaprakash@gmail.com) : Effect of aluminium doping on the structural, morphological, electrical and optical properties of ZnO thin films prepared by sol-gel dip coating. Indian J pure appl Phys 2016, 54(11), 689-93.

Aluminum doped zinc oxide (AZO) thin films with 0-5 at.% aluminum content have been prepared by sol-gel dip coating technique. The thickness of the films has been measured using alpha step method. The structural and morphological properties have been studied, respectively, using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Higher intensity zinc oxide (ZnO) peak (002) has been observed in 1 at.% aluminum doped film with 450 °C of annealing temperature. The grains are more densely packed in the films doped in 1 at.% aluminum content. The grains have tendency to decrease in size as the aluminum content increases. Electrical resistivity measurement technique reveals that electrical resistance decreases with increase of film thickness. The lowest resistivity of the AZO thin film is 3.2x10^{-2 Ω. Optical properties of AZO thin films are tested by UV-visible spectroscopy, while comparing with all the films 0.5 at.% aluminum doped film produces more than 90% of transmittance.}

8 illus, 15 ref

004222   Atta A;Abdel-Galil A (Radiation Physics Dep, National Centre for Radiation Research and Technology (NCRRT), Atomic Energy Authority (AEA), Cairo, Egypt, Email: alyatta2001@yahoo.com) : Improved surface properties of PTFE polymer films using broad ion source. Indian J pure appl Phys 2016, 54(9), 551-6.

Main objective of this paper is to improve the surface properties of the polytetrafluoroethylene (PTFE) polymer films by ion beam irradiation with 2 keV Ar^{+ energy and various ion fluence ranging from 1x1017 to 3xl017 ions/cm2. Various characterization techniques, namely, X-ray diffraction (XRD), UV-Vis spectroscopy and electrical measurements have been used to confirm these changes. XRD measurement shows the decrease of the XRD peak intensity and reflects some loss of crystallinity after irradiation. The UV-Vis has shown a shift of the absorption edge of irradiated samples towards the visible region. The band gap energy E_g was calculated using Tauc's relation, and its value decreases with an increase of ion fluence for all irradiated samples. Increasing ion fluence leads to slight increase in electrical conductivities (σ_dc and σ_ac) and dielectric loss ε₂ for PTFE samples.}

12 illus, 1 table, 39 ref

004221   Ahmad N;Mahmoud S T;Ahmad M (Physics Dep College of Science, UAE Univ, PO Box 15551 Al-Ain, United Arab Emirates, Email: nafis.jmi@gmail.com) : Stability of a large amplitude plasma wave to oscillating two-stream instability. Indian J pure appl Phys 2016, 54(11), 720-6.

The stability of a long wavelength large amplitude plasma wave, generated in a laser wakefield accelerator at moderately relativistic laser intensity, to oscillating two-stream instability has been examined. In the limit when the oscillatory velocity of electrons due to the plasma wave, V₀, exceeds the electron thermal speed, the short wavelength ω^{2 = ω2_P + |k.v₀|2/2. In the four wave parametric process, involving the pump plasma wave, a short wavelength low frequency quasimode and two short wavelength plasma wave sidebands, the pump and the sidebands exert a ponderomotive force on the electrons driving a low frequency quasimode. The electron density perturbation associated with this mode couples with the pump driven electron oscillatory velocity to produce nonlinear currents driving the sidebands. We find that this process has no growth when the ion motion is ignored. However, with the inclusion of ion motion the parametric instability is important on the time scale of an ion plasma period.}

4 illus, 24 ref

003144   Meena K;Balavijayalakshmi J (Physics Dep, PSGR Krishnammal College for Women, Coimbatore-641 004, Tamil Nadu) : Effect of Co-Ag doping on structural and optical properties of zinc oxide nanoparticles. Adv appl Res 2016, 8(1), 19-23.

Co-Ag co-doped Zinc oxide nanoparticles were synthesized by chemical co-precipitation method. The synthesized nanoparticles were subjected to X-ray diffraction technique and the average crystallite size was found to be around 29-31 nm. The crystallite size increased as the cobalt concentration increased. The optical properties were characterized by UV-Vis and PL spectral analysis. The FT-IR spectra of the samples were recorded and the characteristic absorption bands shifted to lower values as the cobalt concentration increased. The SEM analysis showed sphere shaped particles distributed uniformly. These co-doped (Co,Ag) ZnO nanoparticles may be used in optoelectronics, spintronics, as antibacterial reagents to treat diseases caused by bacteria and fungi and in waste water treatment.

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003143   Akhouri B P (Physics Dep, Birsa College, Khunti, Jharkhand) : Equations of state for hard hypersphere fluids in high dimensional spaces. Int J chem Stud 2017, 5(1), 39-45.

Plots for the comparison against the molecular dynamics (MD) computer simulations data of Luban and Michel and plots for the relative percent deviations from the molecular dynamics data of Luban Michel show that the empirical forms of the equations of state have a good agreement over full range of densities both for 4-D and 5-D. The equations of state for 4-D and 5-D hard hypersphere fluids with added additional parameters agree more closely with the available simulation data. It may also be reported here that the difference in compressibility factors below P<60> 0.6 is imperceptible for both 4-D and 5-D hard hyperspheres.

20 illus, 1 table, 23 ref

002156   Sinha P;Sinha N (Physics Dep, H.N.B. Garhwal Univ Campus, Muzaffarnagar, Email: Pauri.piyush03@gmail.com) : Nuclear structure: high energy electron scattering. J Mount Res 2015, 10(Dec), 51-3.

High energy electron scattering is a very powerful tool for studying the geometrical details of nucleus. The studies revealed information on static structure as well as dynamical structure of icleiis. In this paper theoretical analysis of the same has been explained using shell model wave function. This calculation is carried out using resonation group method along with complex generator coordinate technique.

10 ref

002155   Parmar P;Agrawal P;Bajpai R (Electornics and Computer Maintenance Dep, St. Aloysius College (Autonomous), Jabalpur-482 001) : Temperature dependent conductivity of polypyrrole and montmorillonite composites. Ultra Scient phys Sci-Sect B 2015, 27(2), 75-80.

Polypyrrole (PPy) and Montmorillonite (MMT) composites of different weight percentage using Feds as oxidant have been synthesized using in-situ polymerization. The electrical conduction is studied as function of temperature. The electric conductivity increases with an increase in the temperature in each of the composites. Mott's 1-D, 2-D and 3-D variable range hopping (VRH) models have been plotted. The ln(a) versus T^{-1/4 curve has been discussed, wherein the linear relationship provides an evidence for three dimensional variable range hopping electron transport mechanism in all the composites.}

2 illus, 17 ref

002154   Nayeem S M;Rao D K (Physics Dep, Govt. Degree College, Addanki-523 201, Email: krdhanekula@yahoo.co.in) : Comparative analysis of molecular interactions between drugs of aqueous propylene glycol with certain alcohols at 308.15K: an insight from density and viscosity studies. Int J pharm Sci Res 2015, 6(9), 3961-74.

Density, ρ and viscosity, η of drug of aqueous solution of propylene glycol (PG) (3 m and 7 m) with tert-butanol/2-propanol have been measured over the entire composition range of alkanols at 308.15 K. From this experimental data, excess molar volume, V^{E_m, deviation in viscosity, Δη, and excess Gibbs free energy of activation of viscous flow, ΔG*E have been determined. Positive values of Δη, ΔG*E and negative values of VE_m have been observed over the entire composition range in the mixtures studied. The observed positive and negative values of various excess/deviation properties have been attributed to the existence of strong interactions such as geometrical fitting of smaller molecules into the voids created by larger molecules in the liquid mixtures. The excess/deviation properties have been fitted to Redlich-Kister type polynomial and the corresponding standard deviations have been evaluated. The computed partial and excess partial molar volumes data also support the VE_m results. The experimental viscosity data of the liquid mixtures investigated have been correlated with viscosity models such as Grunberg and Nissan; Hind, McLaughlin and Ubbelohde; Katti and Chaudhari.}

32 ref

002153   Mukhopadhyay S (NO, , ) : Experimental study on the fundamentals of plasma physics for the applications in basic sciences and in technology. J nucl Engng Technol 2016, 6(2), 10-13.

In this research paper, few experimental results have been discussed on the basis of total 1547 individual experimental-outputs by the experimental research on plasma physics. The previously invented Paschen curve has been verified. Also, the variations in floating potential with respect to the discharge voltage in the glow discharge plasma system have been briefly discussed. These experimental results may be useful for the applications in basic sciences and in technology. This research paper is highly significant from the administrative point of view to build up a high-level of research-collaboration between India and United Kingdom in all fields of Science and Technology. These total 1547 individual experimental-outputs have been obtained by the author's own hands-on completely.

002152   Bhaduri S;Ghosh D (NO, Deepa Ghosh Research Foundation, Kolkata-700 031) : Speech, music and multifractality. Curr Sci 2016, 110(9), 1817-22.

Audio signal categorization is one of the rudimentary steps in applications like content-based audio information retrieval, audio indexing, speaker identification, and so on. In this work, a rigorous, non-stationary methodology capable of categorization among speech and various music signals is proposed. Multifractal detrended fluctuation analysis method is used to analyse the internal dynamics of the acoustics of digitized audio signal. The test data include speech (non-musical), drone (periodically musical) and music samples of Ragas (having different musicality) from Indian classical music (INDIC). It is found that the degree of complexity and multifractality (measured by width of the multifractal spectrum) changes from the start towards the end of each audio sample. However, the range of this variation is the smallest for speech and drone. The normalized value of the width of the multifractal spectrum is strikingly different for speech and drone. Experimental results show that this parameter can effectively classify speech and drone signals. Further, we have experimented with a number of clips of INDIC Ragas with a range of variation in musicality and mood content. The results show that the width of the multifractal spectrum of the signals can categorize different music signals. In contrast with the conventional stationary techniques for audio signal analysis, we have used the method of complexity I analysis without converting the non-stationary audio signals in frequency domain. We have used basic waveforms of the audio signals after de-noising them.

6 illus, 23 ref

001131   Unnikrishnan C S (NO, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400 005, Email: unni@tifr.res.in) : Double bonanza at the LIGO gravitational wave detectors. Curr Sci 2016, 110(7), 1146-52.

Soon after the two advanced LIGO detectors were ready in September 2015 for a calibrated observation run, a giant gravitational wave burst hit the detectors and were duly recorded as nearly identical chirped signal wave spiralling up in frequency and amplitude from 35 to 250 Hz, with a relative delay of 6.9 ms, well inside the light travel distance of 10 ms between the two detectors. The peak strain amplitude touched 100 times the base sensitivity. Analysis of the 200 ms short event led to the robust conclusion that LIGO detectors saw gravitational waves from two orbiting and merging black holes of nearly 30 solar mass each, at a distance of about 1.3 billion light years. We sketch this double discovery of great scientific and astronomical importance - the terrestrial detection of gravitational waves, ushering in the era of gravitational wave astronomy, and the discovery of a stellar mass binary black hole system, observed during their orbital evolution towards merger and then to the formation of a single stable black hole, all invisible to any other form of astronomy.

3 illus, 24 ref

001130   Singh N P;Singh A K;Singh R R;Gupta K (Mathematics Dep, C.L. Jain (PG) College, Firozabad-283 203, Email: aksinghnpsingh@rediffmail.com) : Magnetohydrodynamic heat and mass transfer flow past an accelerated plate. Ultra Scient phys Sci-Sect B 2015, 27(3), 135-8.

An exact solution of magnetohydrodynamic convective flow with mass transfer past an accelerated vertical plate embedded in a porous medium is investigated. The governing equations are solved using the Laplace-transform technique. The influence of various parameters on the temperature, concentration and velocity as well as on the skin fraction, the rate of heat and mass transfer is studied graphically.

2 illus, 6 ref

001129   Mishra A;Biswal S;Dash S K;Mishra A P;Paikray P (Physics Dep, A.D. Mahavidyalaya, Brahmagiri, Puri) : Hydrodynamic unsteady flow and heat transfer in an elasrico-viscous liquid over an oscillating porous plate in a rotating frame. Ultra Scient phys Sci-Sect B 2015, 27(3), 155-66.

This paper deals with Hydrodynamic unsteady flow and heat transfer in an elastic-viscous liquid over an oscillating porous plate in a rotating frame. The constitutive equation of motion and energy have been developed and solved with the approved boundary conditions. Profiles of velocity of flow and temperature have been drawn varying the fluid parameters involved. The values of skin-friction and the rate of heat transfer are entered in the tables. It is observed that the non- Newtonian parameter, thermal Grashof number, porosity parameter and rotation parameter affect the flow appreciably. Likewise, Prandtl number, porosity parameter and angular velocity influence the temperature field and the rate of heat transfer to a great extent.

3 tables, 4 illus, 18 ref

001128   Kumar M N V S S;Modalavalasa N;Ganesh L; Prasad K S;Rao G S (Electronics and Communication Engineering Dep, Aditya Institute of Technology and Management, Tekkali, Srikakulam-532 201, Email: maniramana@yahoo.com) : New approach for tracking moving objects in underwater environment. Curr Sci 2016, 110(7), 1315-23.

Obstacle avoidance and navigation is a demanding task for an autonomous underwater vehicle (AUV) due to the complex nature of the underwater environment. However, an automatic detection and tracking system is the primary element for an AUV or an aqueous surveillance network. Tracking underwater objects in an active context, represents an ongoing challenge in the field of signal processing. In order to detect the target's presence under water, the echoes reflected by the target are analysed by the receiver. Track accuracy is one of the paramount performance measures of a tracking system. Towards this, various methods such as Kalman filter (KF), extended Kalman filter (EKF) and least squares (LS) have been explored. However, all these methods have their own drawbacks. In this study, a new approach called modified gain EKF has been implemented on the simulated data for tracking of underwater moving object using bearing and elevation measurements. AUV fitted with a single sonar is used for validating the proposed bearing and elevation only tracking (BEOT) algorithm. The performance of the algorithm is evaluated in Monte Carlo simulations and results are presented in stipulated geometries.

14 illus, 24 ref

000043   Yadam S;Singh D;Venkateshwarlu D;Gangrade M K;Shanmukharao Samatham S;Ganesan (UGC-DAE Consortium for Scientific Research, Campus Univ, Khandwa Road, Indore, Email: vganesan@csr.res.in) : Maneto-heat capacity study on kondo lattice system Ce(Ni_1-xCu_x)₂Al₃. Bull Mater Sci 2016, 39(2), 537-41.

Heat capacity studies on the Kondo lattice system Ce(Ni_1-xCu_x)₂Al₃, in the presence of magnetic fields, were reported for x = 0.0-0.4. The physical properties of the intermediate compositions like x = 0.3 and 0.4 were known for their enhanced thermoelectric power and hence have been analysed with an extra interest. It was also shown from the X-ray diffraction that these systems with x = 0.3 and 0.4 were in single phase in terms of sample purity and it stabilized the phases easily with the increase in the Cu doping in the system. The low temperature rise in C_p/T below 10 K under the influence of high magnetic fields was analysed using a multi-level Schottky effect. A gradual decrease of the total angular momentum (J) with the increase of applied magnetic fields indicated a scenario of screening of Ce³⁺ magnetic moment while simultaneously the system settled for the Fermi liquid state. The screening thus seen was in line with the expectations of electrical conductivity measurements on these samples.

6 illus, 1 table, 22 ref

000042   Madolappa S;Anupama A V;Jaschin P W;Varma K B R;Sahoo B (Materials Research Centre, Indian Institute of Science, Bangalore-560 012, Email: bsahoo@mrc.iisc.ernet.in) : Magnetic and ferroelectric characteristics of Gd<. Bull Mater Sci 2016, 39(2), 593-601.

Polycrystalline BiFeO₃ and Bi_0.9Gd_0.1 Fe_1-x Ti_xO₃ (x= 0, 0.01, 0.05 and 0.1) samples were synthesized by solid-state reaction route. Structural, magnetic and ferroelectric properties of these samples were investigated. X-ray powder diffraction (XRD) results confirmed the presence of a significant amount of Bi₂ Fe₄O₉ impurity phase in the undoped BiFeO₃ sample. Mossbauer spectroscopy studies corroborated the XRD studies to confirm the presence of impurity phase. We have observed that gadolinium (Gd³⁺) and titanium (Ti⁴⁺) doping, respectively, on Bi³⁺ and Fe³⁺ sites facilitated a significant reduction in the impurity phase formation in BiFeO₃. Interestingly, Gd³⁺ -doping significantly reduced the impurity phase formation as compared to the undoped BiFeO₃ sample. This impurity phase formation was further overcome by doping higher (x ≥ 0.05) amounts of Ti in BiFeO₃. The crystallographic site occupancies of Gd and Ti were confirmed by Rietveld refinement of XRD data, Mossbauer spectroscopy and magnetization measurements. An enhancement in ferromagnetic properties along with moderate ferroelectric properties have been observed after co-doping. There was an increasing trend in remnant polarization (P_r) with the increase in Ti concentration besides an improvement in the characteristic saturation magnetization. Our results demonstrate that Gd³⁺ and Ti⁴⁺ doping could be used to enhance multifunctional properties of BiFeO₃ ceramics to enable them as potential material for various devices.

5 illus, 4 tables, 35 ref

000041   Aly K A;Afify N;Saddeek Y B;Abousehly A M (Physics Dep, Faculty of Science and Arts Khulais, Jaddah Univ, P.O. Box 80200, 21589 Khulains, Saudi Arabia, Email: kali5@Uj.edu.sa) : Elastic and optical properties of Ge_xSe₂Sb_1-x (0.0 ≤ x ≤ 1.0) glasses. Bull Mater Sci 2016, 39(2), 491-8.

The present study deals with the effect of composition on the elastic and optical properties of Ge_xSe₂Sb_1-x(0.0 ≤ x ≤ 1.0) glasses. The various elastic moduli of these glasses such as Young's modulus (Y) and the bulk modulus (B) along with the micro-hardness (H), Poisson's ratio (σ) and Debye temperature (T_D) were obtained from the values of the longitudinal (v_l) and shear (v_s) ultrasonic velocities. On the basis of measurements of the transmittance and reflectance spectra in the wavelength range of 0.4-2.5 μm the optical constants such as the film thickness (t), the refractive index (n) and the optical band gap (E_g) were investigated with high accuracy. The optically determined bulk modulus of these glasses was in good agreement with that elastically investigated. The obtained results were discussed in terms of the changes in the glass density, electronegativity and electronic polarizability with the variation in antimony content.

7 illus, 3 tables, 46 ref

023288   Zeroual I;Labidi S;Meradji H;Labidi M;Haj Hassan F E (Physics Dep, Faculty of Sciences, Badji Mokhtar Univ, P.O. Box 12, 23000 Annaba, Algeria, Email: hmeradji@yahoo.fr) : Ab initio calculations of fundamental properties of SrTe_1-xO_x alloys. Bull Mater Sci 2016, 39(3), 827-35.

Structural, electronic, optical and thermodynamic properties of the SrTe_1-xO_x alloys (0≤ x ≤ 1) in rock-salt phase are calculated using the full potential-linearized augmented plane wave (FP-LAPW) method within density functional theory. The exchange-correlation potential for structural properties was calculated by the standard local density approximation (LDA) and GGA (PBE) and the new form of GGA (WC) which is an improved form of the most popular Perdew-Burke-Ernzerhof (PBE), while for electronic properties, in addition to LDA, GGA corrections; Engel-Vosko GGA (EV-GGA) and modified Becke-Johnson (mBJ) schemes were also applied. The results show that the use of GGA (WC) in our calculations is more appropriate than GGA and LDA and gives a good description of structural properties such as lattice parameters and bulk modulus. Our investigation on the effect of composition on lattice constant, bulk modulus and band gap for ternary alloys shows almost nonlinear dependence on the composition. In addition to FP-LAPW method, the composition dependence of the refractive index and the dielectric constant was studied by different models. On the other hand, the thermodynamic stability of this alloy was investigated by calculating the excess enthalpy of mixing ΔH_m as well as the phase diagram.

7 illus, 5 tables, 52 ref