008356   Sahoo S;Sit S K (Electronics & Instrumentation Engineering Dep, National Institute of Technology, Silchar-788 010, Email: swagatdebmsit@yahoo.co.in) : Dielectric relaxation phenomena of alkyl acrylate on complexation with phenol dissolved in carbon tetrachloride under static and high frequency electric field. Indian J pure appl Phys 2017, 55(3), 207-17.

Double relaxation times τ₂ and τ₁ due to whole molecular rotation and the flexible parts of the binary (jk) polar mixture of alkyl acrylate (j) and phenols CCl₄ (i) at 35°C are estimated using susceptibility data under 9.37 GHz electric field. Five systems out of twelve exhibit τ₂, τ₁ and μ₂, μ₁. τ₂'s of all systems show gradual increase with the chain length of esters offering hindrance to the rotation of the molecule. The relative contributions c₁ and c₂ due to τ₁ and τ₂ for five systems in terms of x_ijk/x_oijk-w_jk and x_ijk/x_oijk-w_jk curve at w_jk→o are estimated along with symmetric τ_s, characteristics τ_cs establishing the symmetric distribution of relaxation behavior. The estimated μ's and τ₂'s agreed with the reported and measured values. The solute-solute and solute-solvent molecular associations through H-bonding are also as certained.

8 illus, 3 tables, 22 ref

008355   Sahoo S K;Swain M;Sahoo B K (Physics Dep, K I I T Univ, Bhibaneswar-751 024, Email: bksahoo.phy@nitrr.ac.in) : Effect of built-in-polarization field on mean free path of phonons in binary nitrides. Indian J pure appl Phys 2017, 55(3), 179-86.

In this paper, the built-in-polarization field effect on mean free path of acoustic phonons in bulk wurtzite binary nitrides (GaN, AlN) has been theoretically investigated. Due to the modification of elastic constant of the material by the effect of polarization field, there is a corresponding enhancement in group velocity and Debye frequency of phonons. The scattering rate of phonons also affected by this field, as it is a function of velocity or/and Debye frequency. The result shows that polarization field suppresses various scattering rates as well as combined scattering rate of phonons. This implies an increased combined relaxation time of phonons. Hence, the mean free path of phonons increases. Thus, phonons travel freely for a longer distance between two successive scatterings. It is found that, the mean free path of low frequency phonons is longer than that of the high frequency phonons. It indicates that, the low frequency phonons are significantly affected by the built-in-polarization field. This can enhance thermal transport properties of the material, when built-in-polarization field taken into account. It may be a method to control the thermal transport properties of such materials by the application of electric field in a desired way, which can be considered in addressing thermal management issues in nitride based optoelectronic devices to minimize self-heating effects.

2 illus, 3 tables, 34 ref

008354   Ramesh T;Murthy S R (Physics Dep, BVRIT Hyderabad College of Engineering for Women, Hyderabad-500 090, Email: rameshouphysics@gmail.com) : Electromagnetic properties of nanocrystalline Al<. Bull Mater Sci 2016, 39(6), 1593-1601.

The effect of Al^{3+ substitution on electromagnetic properties has been studied for nanocrystalline Mg_0.8Cu_0.2Mn_0.2Mn_0.05Al_xFe_1.95-xO< v>4 ferrites, wherein x varies from 0 to 0.4 in steps of 0.1. These ferrites were synthesized by using microwave hydrothermal method and then characterized using X-ray diffractometer(XRD), Fourier transform infrared and transmission electron microscopy. The synthesized powders were densified using microwave sintering method at 950°C/50 min. Structural and surface morphology of sintered samples were characterized using XRD and atomic force microscopy, respectively. The complex permittivity and permeability properties were measured over a frequency range 100 Hz-1.8 GHz. The temperature variation of magnetic properties were measured in the temperature range of 300-650K. The electrical and magnetization studies inferred that the values of d.c. resistivity increases by 27, whereas saturation magnetization decreases linearly from 38.6 to 23.0 emu g-1 and Curie temperature was found to be decreased from 628 to 513 K with an increase of Al3+ ions. The low dielectric, magnetic losses, moderate saturation magnetization and high-temperature stability properties exhibited by Al3+ substituted MgCuMn ferrites make them find applications in microwave devices, such as circulators and isolators etc. The applicability of present samples for microwave devices has been tested by the measurement of ferromagnetic resonance linewidth at K_a band.}

10 illus, 2 tables, 25 ref

008353   Punniyakotti J;Ponnusamy V (Physics Dep, Meenakshi Sundarajan Engineering College, Chennai-600 024, Email: vps@annauniv.edu) : Radionuclides of <. Indian J pure appl Phys 2017, 55(3), 218-30.

The natural radioactivity content of ^{238U, 232Th and 40K in beach sand of southern regions of Tamilnadu, India have been analyzed using gamma-ray spectroscopy. From the spectral analysis, the average radioactivity content of 238U, 232Th and 40K in beach sand samples are 8.77 ± 3.77, 76.48 ± 4.74 and 202.87 ± 26.72 Bq.kg-1, respectively. Univariate statistics has been applied successfully to assess the distribution of radionuclides and it shows that the decay series radionuclides such as 238U and 232Th are non-existence of normal distribution in the sands; however non-decay series radionuclide of 40K is distributed uniformly. Radiological parameters such as absorbed dose rate, annual effective dose equivalent, annual gonadal dose equivalent, radium equivalent, hazard index, gamma index, activity utilization index, alpha index and excess lifetime cancer risk have been calculated to know the complete radiological status of the coastal sands. The results of the present study indicate that the natural radioactivity content in the beach sands do not pose any radiation effect to the members of public in the southern region of Tamilnadu coast.}

9 illus, 3 tables, 47 ref

008352   Panwar M;Sharma S K;Panwar S (Physics Dep, MMEC, Maharishi Markandeshwar Univ, Ambala-133 207, Email: monikaverma05@gmail.com) : Analysis of volume dependence of gruneisen ratio of forsterite. Indian J pure appl Phys 2017, 55(3), 203-6.

The purpose of the present paper is to derive a new empirical relationship for the volume dependence of Gruneisen ratio (?) by using simple and straightforward approach. The results thus obtained for Forsterite (Mg₂SiO₄) from the two different methods are identical to each other. Consistency of calculated values with those values compiled by Cynn H, Carnes J D, Anderson O L, J Phys Chem Sol, 57 (1996) 1593 reveals the validity of the formulation. It is also found that the heat capacity does not influence the change in (γ) with the volume ratios in the studied range.

1 illus, 2 tables, 31 ref

008351   Palla P;Uppu G R;Ethiraj A S;Raina J P (Center for Nanotechnology Research, VIT Univ, Vellore-632 014, Email: penchalaiah.palla@vit.ac.in) : Bandgap engineered graphene and hexagonal boron nitride for resonant tunnelling dode. Bull Mater Sci 2016, 39(6), 1441-51.

In this article a double-barrier resonant tunnelling diode (DBRTD) has been modelled by taking advantage of single-layer hexagonal lattice of graphene and hexagonal boron nitride (h-BN). The DBRTD performance and operation are explored by means of a self-consistent solution inside the non-equilibrium Green's function formalism on an effective mass-Hamiltonian. Both p- and n-type DBRTDs exhibit a negative differential resistance effect, which entails the resonant tunnelling through the hole and electron bound states in the graphene quantum well, respectively. The peak-to-valley ratio of approximately 8 (3) for p-type (n-type) DBRTD with quantum well of 5.1 nm (4.3 nm) at a barrier width of 1.3 nm was achieved for zero bandgap graphene at room temperature.

12 illus, 1 tabel, 38 ref

008350   Nikoufard M;Alamouti M K (Electronics Dep, Faculty of Electrical and Computer Engineering, Kashan Univ, Kashan, Iran) : Full analysis of a high-bandwidth microring-based PIN modulator. Indian J pure appl Phys 2017, 55(3), 198-202.

This study presents a new simulation strategy for a high-speed microring-based PIN modulator using the finite element method. It includes dc and transient simulations of the electro-optical behavior of the device. Variations in the effective refractive index and their effect on the optical output fields are determined by applying a reverse bias voltage pulse to the device. The frequency responses have been calculated for the microring modulator and 3 dB bandwidth. Calculations show a 3 dB bandwidth of over 115 GHz for a ring with a radius of 8 μm and a width of 0.5 μm at -7 V biasing voltage.

9 illus, 1 table, 14 ref

008349   Nair R V (Laboratory for Nano-scale Optics and Meeta-materials (LaNOM), Physics, Indian Institute of Technology (IIT), Ropar, Rupnagar, Punjab-140 001, Email: rvnair@iirpr.ac.in) : Self-assembled photonic crystals with tunable optical properties. Proc Indian Natn Sci Acad 2016, 82(4), 1249-57.

We have studied the tunable photonic stop gaps in three-dimensionally ordered photonic crystals in the visible and near-infrared wavelength ranges. Structural analysis shows the (111) plane of the crystal with fewer imperfections. Angle-resolved photonic stop gaps indicate the coupling between the Bragg waves diffracted by different crystal planes. The measured Bragg wave coupling is in good agreement with theoretical calculations. The new diffraction peak arises at the Bragg wave coupling is identified as from the (-111) plane of the fcc Brillouin zone. The modification of spontaneous emission of embedded quantum emitters inside the photonic crystals is studied using laser-induced emission measurements. We have achieved a suppression of 51% in the emission intensity at the stop gap wavelength. At higher excitation energy, strong band-edge induced mirrorless lasing is demonstrated. Our results have applications in wide variety of wave propagation in materials, solid state lighting, and nano-lasers.

5 illus, 24 ref

008348   Murtaza G;Ullah M;Ullah N;Malika Rani; Muzammil M;Khenata R;Ramay S M;Khan U (Materials Modeling Laboratory, Physics Dep, Islamia College Univ, Peshawar 25000, Pakistan, Email: murtaza@icp.edu.pk) : Structural, elastic, electronic and optical properties of bi-alkali antimonides. Bull Mater Sci 2016, 39(6), 1581-91.

The structural parameters, elastic constants, electronic and optical properties of the bi-alkali antimonides (Na₂KSb, Na₂RbSb, Na₂CsSb, K₂RbSb, K₂CsSb and Rb₂CsSb) were calculated using state-of-the-art density functional theory. Different exchange-correlation potentials were adopted to predict the physical properties of these compounds. The calculated structural parameters are found in good agreement with the available experimental and theoretical results. All the compounds are mechanically stable. The compounds Na₂KSb, K₂RbSb, K₂CsSb and Rb₂CsSb have direct bandgaps, in which chemical bonding among the cations and anions is mainly ionic. Furthermore, the optical properties of these compounds are described in detail in terms of the dielectric function, refractive index, reflectivity, optical conductivity and absorption coefficient.

6 illus, 9 tables, 36 ref

008347   Momeni M M (Chemistry Dep, Isfahan Univ of Technology, Isfahan 84156-8311, Iran, Email: mm.momeni@cc.iut.ac.ir) : Dye-sensitized solar cell and photocatalytic performance of nanocomposite photocatalyst prepared by electrochemical anodization. Bull Mater Sci 2016, 39(6), 1389-95.

This study compares different Fe-doped TiO₂ nanostructures in terms of their photocatalytic performance. Iron-doped TiO₂ nanostructures (FeTNs) were prepared by in situ anodizing of titanium in a single-stepprocess in the presence of 3, 9, 15 and 21 mM K₃Fe(CN)₆. Potassium ferricyanide was used as the iron source. Prepared films are amorphous, so these layers were thermally annealed. The effect of iron doping on the photoelectrochemical properties (including dye-sensitized solar cells) and photocatalysis properties (decomposition of methomyl) was investigated. In all investigated cases, the sample C, which was formed by anodizing in a ethylene glycol electrolyte containing 9 mM K₃Fe(CN)₆, exhibited better performance than the bare TiO₂ and FeNTs fabricated using other iron concentrations. This study demonstrated a feasible and simple anodizing method to fabricate an effective, reproducible and inexpensive photocatalyst for various applications.

8 illus, 2 tables, 8 ref

008346   Mamgain A;Upadhyay T C (Physics Dep, H N B Garhwal Univ, Srinagar-246 174, Email: anubhuti.mamgain01@gmail.com) : Temperature dependence of ferroelectric mode frequency, dielectric constant and loss tangent in CsH₂PO₄ and deuterated CsH₂PO₄ crystals. Indian J pure appl Phys 2016, 54(12), 771-6.

The pseudo-spin lattice coupled mode model by adding third- and fourth-order phonon anharmonic interactions and extra spin-lattice interaction term has been considered for CsH₂PO₄ (abbreviated CDP) and deuterated CsH₂PO₄ (abbreviated DCDP) crystals. Expressions for shift and width of response function, vibrational normal mode frequency, dielectric constant and loss tangent have been evaluated. Double time temperature dependent Green's function method has been used for derivation. Fitting the values of model parameters in expressions, the temperature dependence of soft mode frequency, dielectric constant and loss tangent have been calculated. Theoretical results are in agreement with experimental results reported by Blinc et al.

6 illus, 1 table, 17 ref

008345   Mallick P (Physics Dep, North Orissa Univ, Baripada-757 003) : Effect of solvent on the microstructure and potical band gap of ZnO nanoparticles. Indian J pure appl Phys 2017, 55(3), 187-92.

ZnO nanoparticles have been synthesized by chemical route using different solvents. X-ray diffraction characterization of the samples indicated ZnO nanoparticles crystallize in wurtzite phase c/a with for all the samples is <126> 1.6. Though all the samples exhibit same crystal structure, the microstructure of ZnO nanoparticles is influenced with solvent. The ZnO nanoparticles have been synthesized using ethanol as solvent has smaller crystallite size than that obtained for ZnO nanoparticles synthesized using propanol and ethylene glycol as solvent. In accordance with crystallite size variation, the lowest and highest specific surface area has been calculated for ZnO nanoparticles synthesized using propanol and ethanol as solvent, respectively. Stress analysis using lattice parameter indicated that the crystallites of all ZnO samples experience compressive stress and the magnitude of the stress is nearly twice for ZnO nanoparticles synthesized with ethanol than that obtained for ZnO nanoparticles synthesized using ethylene glycol as solvent. UV-visible characterization of these samples indicated that the bang gap of ZnO nanoparticles is not affected much with the solvent. The refractive index and electron polarizability for all samples have been determined from the optical band gap of corresponding samples.

6 illus, 3 tables, 32 ref

008344   Krasil'Nikov V N;Shalaeva E V;Baklanova I V; Melkozerova M A;Kuznetsov M V;Zabolotskaya E V;Gyrdasova O I; Buldakova L Y U;Murzakaev A M (NO, Institute of Solid State Chemistry of the Ural Branch of the Russian A, Ekaterinburg 620990, Russian Federation, Email: shalaeva@ihim.uran.ru) : Synthesis, structure and spectroscopic characteristics of Ti(O,C)₂/carbon nanostructured globules with visible light photocatalytic activity. Bull Mater Sci 2016, 39(6), 1569-79.

A morphology-controlled facile synthesis of titanium-glycolate precursors with subsequent annealing in He and air atmospheres has been exploited for the production of nanostructured composite globules, whiskers and plates of C-modified titanium dioxide. Characterisation tests proved the as-obtained globule composites to exclusively exhibit high-specific surface area (up to 150-170 m22 g^{-1), thus being useful for photocatalytic applications inthe visible-light region. The combination of the electron paramagnetic resonance, X-ray photoelectron spectroscopy, absorption spectroscopy and transmission electron microscopy revealed the presence of three kinds of carbon in the globules: a small bandgap (with measured width of 0.8 eV) amorphous carbon surrounding the anatase nanocrystallites,C-containing radicals including carbonates on the surface of TiO₂ and interstitial carbon in the oxygen position of the TiO₂ lattice. It was found that the maximum visible-light photocatalytic activity of the globules is determinedby the optimal surface concentration of amorphous carbon of about 0.002 wt. m-2. Under these conditions, the highest synergic photosensitising effect on TiO₂ nanocrystallites of all three kinds of carbon is expected.}

12 illus, 1 table, 48 ref

008343   Hurma T (Physics Dep, Anadolu Univ, TR 26470, Eskisehir, Turkey, Email: tulayhurma@gmail.com) : Characterization of zincblende CuInS₂ nanostructured film: the XRD, Raman, FT-IR and UV-vis spectroscopical investigations. Indian J pure appl Phys 2016, 54(12), 797-801.

Zincblende semiconductor CuInS₂ has not been focus of studies until recently. Ultrasonic spray pyrolysis (USP) method is used to deposit zincblende CuInS₂ nanostructured film on glass substrate at 250 °C in this study. The film was characterized by vibrational (FT-IR and Raman) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectra. The crystallite size was calculated to be around 30 nm by using the well- known Scherrer equation with the peak corresponding to (111) plane. The Raman peak at 306 cm^{-1 is assigned to the A₁ mode of the CuAu-ordered CuInS₂. Thus, metastable cubic zincblende structure would be evidenced. The absorption coefficient of the film has been found to be in the order of 104-105 cm-1, which make it promising for an intensive optoelectronic application.}

5 illus, 39 ref

008342   Gupta D K;Verma M;Sharma K B;Saxena N S (Centre for Converging Technologies, Rajasthan Univ, Jaipur-302 004, Email: deekap.nanoconverge@gmail.com) : Synthesis, characterization and optical properties of CdSe/CdS and CdSe/ZnS core-shell nanoparticles. Indian J pure appl Phys 2017, 55(2), 113-21.

Controlled organic synthesis method used for the preparation of cadmium selenide (CdSe) quantum dots, which are covered with cadmium sulfide (CdS) and zinc sulfide (ZnS) using TOP mediated has been presented in this paper. The size, shape, internal structure, chemical composition and functional groups of the core-shell nanoparticles were analyzed using X-ray diffraction, transmission electron microscopy, high resolution transmission electron microscopy, energy dispersive spectra and FTIR. These studies show that the particle size is in 2-10 nm range with hexagonal phase. The optical properties were analyzed through UV-visible spectroscopy, photoluminescence spectroscopy and micro-Raman spectroscopy. Photoluminescence blue shift and broadening of Raman spectrum further confirm the narrow size of particles.

8 illus, 33 ref

008341   Gueddouh A;Bentria B;Lefkaier I K;Bourourou Y (Laboratoire de Physique des Materiaux, Universite Amar Telidji de Laghouat, BP37G, Laghouat 0300, Algeria, Email: a.gueddouh@mail.lagh.univ.dz) : Effect of spin polarization on the structural properties and bond hardness of F2_xB (x = 1,2,3) compounds first-principles study. Bull Mater Sci 2016, 39(6), 1427-34.

In this paper, spin and non-spin polarization (SP, NSP) are performed to study structural properties and bond hardness of Fe_xB (x = 1,2,3) compounds using density functional theory (DFT) within generalized gradientapproximation (GGA) to evaluate the effect of spin polarization on these properties. The non-spin-polarization results show that the non-magnetic state (NM) is less stable thermodynamically for Fe_xB compounds than spinpolarization by the calculated cohesive energy and formation enthalpy. Spin-polarization calculations show that ferromagnetic state (FM) is stable for FexB structures and carry magnetic moment of 1.12, 1.83 and 2.03 μB in FeB, Fe₂B and Fe₃B, respectively. The calculated lattice parameters, bulk modulus and magnetic moments agree well with experimental and other theoretical results. Significant differences in volume and in bulk modulus werefound between the ferromagnetic and non-magnetic cases, i.e., 6.8, 32.8, respectively.We predict the critical pressure between ferromagnetic and non-magnetic phases. The model for hardness calculation using Mulliken population coupled to semi-empirical hardness theory proved effective in hardness prediction for the metal borides which agree well with the experimental values. These results would help to gain insight into the spin-polarized effect on the structural and bond hardness.

2 illus, 8 tables, 45 ref

008340   Fu Z H;Liu J G (School of Elementary Education, Wuhan City Vocational College, HuBei-430 064, Email: 395625298@qq.com) : Exact periodic cross-kink wave solutions for the (2 + 1)-dimensional Boiti-Leon-Manna-Pempinelli equation. Indian J pure appl Phys 2017, 55(2), 163-7.

Based on the extended homoclinic test technique and the Hirota's bilinear method, the (2+1)-dimensional Boiti-Leon-Manna-Pempinelli equation is investigated which describes the fluid propagating and can be considered as a model for an incompressible fluid. With the aid of symbolic computation, we introduce two new Ansatz functions to discuss the multiple periodic-soliton solutions of the (2+1)-dimensional Boiti-Leon-Manna-Pempinelli equation. Some entirely new periodic-soliton solutions are presented. The figures corresponding to these solutions are illustrated to show abundant physics structures.

5 illus, 28 ref

008339   Exinci N;Kavaz E;Cinan E;Sevindik C (Physics Dep, Science Faculty, Ataurk Univ, 25240 Erzurum, Turkey, Email: esrakvz@gmail.com) : Elemental analysis of six mines in erzincan region using wavelength-dispersive X-ray fluorescence spectrometry. Asian J Chem 2016, 28(3), 489-92.

This investigation concentrated on mines in the eastern Erzincan region of Anatolia, Turkey. Wavelength-dispersive X-ray fluorescence spectrometry was used to determine elemental concentrations of the ores taken from six different mines. The presence of C, O, Mg, Al, Si, P, Cl, K, Ca, Ti, V, Cr, Mn, Zn, As, Sr and Ba elements in ores were found. The relative errors for results have been given ± 7%.

3 illus, 1 table, 6 ref

008338   Ersoz O A;Lambrecht E Y;Soylu H M (Nuclear Applications Dep, Institute of Nuclear Science, Ege Univ, Bornova, 35100, Izmir, Turkey, Email: ftmyurt@gmail.com) : Tungsten-ethylene vinyl acetate (EVA) composite as a gamma rays shielding material. Indian J pure appl Phys 2016, 54(12), 793-6.

Lead is a highly toxic metal, also heavy in personal shielding. This negative aspect decline us to search for alternative shielding material that is free of toxic effect, environment friendly, lighter and easy to use individually. Polymer, being lighter, may constitute an alternative to lead, but it has a much lower density and does not serve in gamma shielding by it. Therefore, high density tungsten could be added to polymer in order to shield gamma rays. In this study ethylene vinyl acetate (EVA) and tungsten were mixed in certain amounts and thus discs have been produced from this mixture. The results show that EVA-Tungsten composite is an effective shielding material for gamma shielding.

3 illus, 2 tables, 20 ref

008337   Das J C;De D (Computer Science and Engineering Dep, Swami Vivekananda Institute of Science & Technology, Kolkata-700 145, Email: jadav2u@gmaill.com) : Optimized multiplexer design and simulation using quantum dot-cellular automata. Indian J pure appl Phys 2016, 54(12), 802-11.

Recent trends in nano technological field are the exploitation of quantum dot-cellular automata (QCA) as a substitute in advance to existing transistor based CMOS technology to fabricate nano-circuit. Ultra low heat dissipation, faster clocking and high device density make the QCA as a raising research area in nanotechnological field to suppress the FET based circuit. This paper illustrates a simple and basic method to design QCA based 2:1 multiplexer at nanoscale. The proposed 2:1 multiplexer is compared with the previously designed 2:1 multiplexer in account of circuit density, clock zone numbers, amount of QCA cell used to design the circuit and the density consumed by all QCA cell over total density of the circuit is depicted. This comparative analysis has approved the efficiency of the proposed design. The circuit is implemented and proved using QCA designer-2.0.3.

23 illus, 4 tables, 45 ref

008336   Chandrasekar L B;Gnanasekar K;Karunakaran M; Chandramohan R (Physics Dep, The Americal College, Madurai-625 002, Email: brunochandrasekar@gmail.com) : Effect of 'Al' concentration on spin-dependent resonant tunnelling in InAs/Ga₁- y Aly as symmetrical double-barrier heterostructures. Bull Mater Sci 2016, 39(6), 1435-40.

The effect of 'Al' concentration on spin-dependent tunnelling in strained non-magnetic symmetric double-barrier semiconductor has been theoretically investigated. The separation between spin-up and spin-down components, barrier transparency, polarization efficiency and tunnelling lifetime were calculated using the transfer matrix approach. The separation between spin-up and spin-down resonances and tunnelling lifetime were reportedfor the first time in the case of InAs/Ga_1-yAl_yAs heterostructures for various 'Al' concentrations and for various barrier widths. Cent percentage polarization can be obtained in this strained non-magnetic double-barriersemiconductor even without any external field.

6 illus, 15 ref

008335   Bucurgat M;Ozdemir S;Firat T (Physics Dep, Faculty of Science, Gazi Univ, 06500 Ankara, Turkey, Email: mahmut.bucurgat@gazi.edu.tr) : Photocurrent analysis of AgIn₅S₈ crustal. Bull Mater Sci 2016, 39(6), 1521-9.

The photocurrent (PC) spectrum of AgIn₅S₈ crystal consists of a single peak, which provides to determine the bandgap energy by applying the Moss rule. The temperature dependence of the bandgap energy was alsocalculated. The PC dramatically increased by pre-illumination with light having wavelength corresponding to the bandgap of AgIn₅S₈. The temperature-dependent PC of the sample was measured at different temperatures from80 to 300 K and the PC spectrum consisted a single broad peak. Thermal quenching of the PC was observed to start at <126>105 K and the PC completely quenched at <126>180 K. The quenching mechanism was discussed in terms of the two-centre model. The height of the PC peak rised linearly with applied voltage up to 5.0 V under constant intensity of light. Similarly, the dark current-voltage characteristics consisted of a single region dominating an ohmicbehaviour, and no space charge limited region was apparent at various temperatures up to 20 V.

10 illus, 28 ref

008334   Barman J;Sultana F (Physics Dep, ADP College, Nagaon-782 002, Email: jayantabarman2006@gmail.com) : Optoelectronic and antimicrobial activity of composite zinc oxide and cadmium sulphide quantum dots and application in water treatment. Indian J pure appl Phys 2017, 55(3), 231-6.

In the present study, we report the synthesis of composite zinc oxide and cadmium sulphide nanoparticles by a chemical route. ZnO-CdS nanocomposites have been gaining much importance as they show fascinating opto-electronic properties such as tunable band gap and the nanomaterials are suitable for fast photon absorption, transportation and collection. The prepared composite nanoparticles have been characterized by UV-VIS absorption, X-ray diffraction (XRD) and TEM, AFM and FTIR observation. UV-VIS optical spectroscopy study has been carried out to determine the band gap of the composite zinc oxide and cadmium sulphide thin film and it shows a blue shift with respect to the bulk value. The nanocomposites show enhanced optio -electronic properties compared to the individual constituents. The band gap of CdS-ZnO nanocomposites depend on various experimental parameters such as reaction time, concentrations of cadmium salt, and also chemical nature of the cadmium salt. The band gap value of the ZnO-CdS nanocrystalline films are obtained in the range of 3.88-4.14 eV which is higher than that of bulk value of ZnO (3.3 eV) and CdS (2.42 eV). The synthesized nanoparticles exhibited high antibacterial activity and can be used for water purification.

7 illus, 3 tables, 31 ref

008333   Azeem;Badruddin A I A;Idris M Y I;Nik-Ghazali N;Salman Ahmed N J;Al-Rashed A A A A (Computer System & Technology Dep, Malaya Univ, Kuala Lumpur, Malaysia, Email: irfan_magami@rediffmail.com) : Conjugate heat and mass transfer in square porous cavity. Indian J pure appl Phys 2016, 54(12), 777-86.

The present article deals with the issue of heat and mass transfer in a square porous cavity having a small solid wall or block inserted at various places at bottom surface. The main objective is to investigate the effect of size of solid wall and its location inside the porous cavity on double diffusive convention. The heat and mass transfer behavior are governed by momentum, energy and concentration equations which are converted into a set of finite element equation with the help of Galerkin method. The left surface of cavity is maintained at higher temperature and concentration, T_h and C_h as compared to that of right surface at T_c and C_c. The results are presented in terms of thermal, concentration and fluid flow profiles across the porous cavity.

13 illus, 2 tables, 36 ref

008332   Arshad M A;Maaroufi A;Pinto G;El-Barkany S; Alidrissi A (Chemistry Dep, Mohammed V Univ, Faculty of Sciences, Laboratory of Composite Material, P.O. Box 1014, Rabat-Agdal 10106, Morocco, Email: maaroufi@fsr.ac.ma) : Morphology, thermal stability and thermal degradation kinetics of cellulose-modified urea-formaldehyde resin. Bull Mater Sci 2016, 39(6), 1609-18.

This article reports a study on the structural characterization and evaluation of thermal degradation kinetics of urea-formaldehyde resin modified with cellulose, known as UFC resin. Structural characterization of UFC undertaken by scanning electron microscopy, Fourier transform infrared and X-ray diffractionanalyses reveals that the resin is fairly homogenous, and it constitutes of partly crystalline structure including urea-formaldehyde/cellulose interface morphology different from UFC precursors. Measurement of inherent thermal stability, probing reaction complexity and the thermal degradation kinetic analysis of UFC have been carried out by thermogravimetric/differential thermal analyses (TGA/DTA) under non-isothermal conditions. The integral proceduredecomposition temperature elucidates significant thermal stability of UFC. TGA/DTA analyses suggest highly complicated reaction profile for thermal degradation of UFC, comprising various parallel/consecutive reactions.Different differential and integral isoconversional methods have been employed to determine the thermal degradation activation energy of UFC. Substantial variation in activation energy with the advancement of reaction verifiesmulti-step reaction pathway of UFC. A plausible interpretation of the obtained kinetic parameters of UFC thermal degradation with regard to their physical meanings is given and discussed in this study.

7 illus, 2 tables, 56 ref

008331   Andal C;Murugakoothan P (Physics Dep, Dr. M.G.R. Educational and Research Institute Univ, Chennai-600 095, Email: murugakoothan03@yahoo.co.in) : Linear and third order non-linear optical properties of urea salicylic acid crystal. Asian J Chem 2016, 28(4), 797-800.

An organic non-linear optical crystal urea salicylic acid was grown by slow evaporation method using the mixed solvent of ethanol and water in equal ratio. The lattice parameters of urea salicylic acid crystal were obtained by single X-ray diffraction study. The optical transmittance study revealed the good transmission window of the urea-salicylic acid and its suitability for optical applications. The non-linear refractive index, n₂, absorption coefficient, β and third order susceptibility, x^{(3) have been measured through the Z-scan technique with He-Ne laser at 632.8 nm. The grown urea salicylic acid crystal exhibits two photon absorption and self-defocussing performance.}

3 illus, 1 table, 16 ref

007346   Traore P T;et al. (Laboratory of Semiconductors and Solar Energy, Physics Dep, Faculty of Science and Technology, Cheikh Anta Diop Univ, Dakar, Senegal, Email: gsissoko@gmail.com) : Study by numerical method of thermal transfer transient through a two-plaster insulating material undergoing heating to the front face. Int J pure appl Sci Technol 2016, 33(1)-37(2), 1-1011-17.

In this study, we show the heat storage phenomena by an insulation towplaster from a numerical study in transient regime.

7 illus, 10 ref

007345   Shihab S S;Rao K G;Gnana Kiran M;Babu S; Sastry S S (Physics Dep, Acharya Nagarjuna Univ, Nagarjunagar-522 510, Email: babu.computers@gmail.com) : Excess thermodynamic and acoustic properties for equimolar mixture of methyl benzoate and alkanols with benzene at 303.15 K. Rasayan J Chem 2017, 10(1), 59-63.

The values of speed of sound (U), density (ρ) and viscosity (η) of pure liquids and the mixture of methyl benzoate + 1-propanol/1-butanol/1-pentanol with benzene were measured over the entire mole fraction range at T = 303.15 K. From these values, various thermo-acoustic parameters such as excess molar volume (V^{E), excess isentropic compressibility (K_sE), and excess free length (L_fE), excess Gibbs free energy (ΔG*E) and excess enthalpy (HE) are calculated. The reason for deviations in these excess parameters is explained based on the intermolecular interactions present in these liquids.}

5 illus, 23 ref

007344   Senthilvelan N;Rajaranjan G;Jegatheesan A; Sivakumar S;Elanchezhiyan J (Physics Dep, Arignar Anna Government Arts College, Attur-636 121, Email: nsenthilvelan2013@gmail.com) : Growth and spectroscopic characterization of urea sulphamic acid crystal: a second-order nonlinear material. Rasayan J Chem 2017, 10(1), 218-25.

An organic single crystal of Urea Sulphamic Acid crystals (US) was grown by slow evaporation technique at room temperature (30øC). The structure of grown crystal was discovered from the X-ray diffraction study and it belongs to the triclinic system. Vibrational modes of Urea Sulphamic crystal was identified by the employing FTIR spectral analysis. UV-Visible spectral studies showed that the lower cut-off wavelength was found to be 236 nm. The impedance study has been carried out and it was showing a maximum at low frequency and decreases with increasing frequency. The thermal stability of the crystal was determined by employing thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) methods for the grown crystal. Second harmonic generation measurement indicate that the efficiency of urea sulphamic acid nonlinear crystal was 1.1 times greater than that of KDP crystal. The analysis results confirmed that these crystals have better nonlinearity and good mechanical strength.

6 illus, 3 tables, 19 ref

007343   Senthilvelan N;Rajarajan G;Sivakumar S; Elanchezhiyan J;Jegatheesan A (Physica Dep, Arignar Anna Government Arts College, Attur-636 121, Email: nsenthilvelan2013@gmail.com) : Bulk growth and physical properties of nonlinear optical material: thiourea sulphamic acid crystal. Rasayan J Chem 2017, 10(1), 245-53.

Nonlinear optical crystals of Thiourea Sulphamic Acid (TS) crystals have been successfully grown by employing slow evaporation technique. The grown crystals were characterized using powder X-Ray diffraction analysis for the crystal system and lattice parameter values. The vibrational behavior was analyzed by means of FTIR spectral technique. UV-Vis-NIR spectral study revealed that the grown crystals have a wide transmission window in the entire visible region with the lower cutoff wavelength 237 nm. The Vicker's microhardness test was carried out on the grown crystals to study the mechanical strength therein, the Vicker's hardness number (Hv) were calculated. The grown crystals of thiourea sulphamic were subjected to thermal studies to confirm that the decomposition of crystals takes place in three different stages making them suitable for device fabrication for frequency conversion applications. Surface Morphology of the grown crystal was confirmed through SEM analysis. The second harmonic generation of the crystals was confirmed by employing Kurtz powder technique to ascertain the nonlinear optical property.

10 illus, 28 ref

007342   Senthamil Selvi C;Valliammai C T;Malliga P; Thenmozhi C;Kannappan V (Physics Dep, Sathyabama Univ, Chennai, Tamilnadu, Email: senthamilc@yahoo.co.in) : Ultrasonic and molecular interaction studies of cinnamaldehyde with acetone in n-hexane. Rasayan J Chem 2017, 10(1), 271-8.

In this work, density, velocity and other acoustical parameters of cinnamaldehyde with acetone in n-hexane have been measured throughout the entire concentration range from the temperature of 293.15, 298.15, 303.15 and 308.15 K at atmospheric pressure. The excess velocity, excess adiabatic compressibility(K^{E), excess free length (L_FE), excess molar volume (V_mE) and excess impedance (ZE) have been computed. The sign and magnitude of these parameters indicate the strength of interactions and shows the formation of charge-transfer complex. Stability Constants (K) and the thermodynamical parameters enthalpy (ΔH), Free Energy (ΔG), Entropy Changes (ΔS) and Correlation coefficient for formation of hydrogen bonded complexes are reported for such complexes. The formation constants of complexes of acetone with aromatic compounds depend on the structure of the donor and acceptor molecules.}

5 illus, 6 tables, 7 ref

007341   Denisova K N;Fantina N P;Ilin A S;Martyshov M N;Vorontsov A S (Physics Dep, Lomonosov Moscow State Univ, Leninskie Gory 1-2, Moscow, 119991, Russia) : Effect of femtosecond laser radiation on the structure and conductivity of boron doped amorphous hydrogenated silicon. Biosci Biotechnol Res Asia 2016, 13(4), 2359-63.

The comparative analysis of the influence of femtosecond laser radiation on the structure and conductivity of undoped and boron-doped amorphous hydrogenated silicon was made in this paper. It has been found that the process of nanocrystals formation in an amorphous matrix by femtosecond laser radiation for undoped amorphous hydrogenated silicon samples begins at lower laser energy densities than for doped samples. Different conductivity of undoped and doped samples of amorphous hydrogenated silicon before femtosecond radiation becomes approximately equal upon radiation with laser fluence of 150-160 mJ/cm^2.

2 illus, 2 tables, 26 ref

007340   Basha S K S;Sunita G S;Vijay Kumar K;Reddy K V B;Rao M C (Solid State Ionics Laboratory, Physics Dep, K.L. Univ, Guntur-525 502, Email: raomc72@gmail.com) : Electrical conduction behaviour of PVP based composite polymer electrolytes. Rasayan J Chem 2017, 10(1), 279-85.

Solid state polymer electrolyte of Mg^{2+ was prepared by doping nano-sized Al₂O₃ particles on PVP complexed with MgCl₂.6H₂O salt by solution cast technique. Electrical conductivity and dielectric properties have been carried-out on to the prepared polymer films. It was found that the conductivity of nano-sized Al₂O₃ doped PVP based solid polymer electrolyte was found to be 1.22 x 10-6 S/cm at room temperature for 85:15 compositions having low activation energy. Dielectric studies were carried-out for the prepared samples on HIOKI 3532-50 LCR Heister Range 42 Hz - 5 MHz. It is observed that magnitude of dielectric permittivity is high in the lower frequency region due to electrode polarization (EP) effect. The dielectric permittivity and loss were increased with increase of temperature.}

10 illus, 2 tables, 73 ref

006329   Zhong M;Xiang X;Liao W;Yan Z H;Yang L;Yang G X;Wu J W;Zheng W G;Yuan X D (School of Physical Electronics, Electronics Science and Technology of China Univ, Chengdu 610054, Email: xiaxiang@uestc.edu.cn) : Effect of uniform helium doping on the optical properties and laser damage performance of sapphire. Indian J pure appl Phys 2016, 54(5), 301-6.

Sapphire samples have been implanted successively by helium ions with a series of energies to obtain a uniform layer of impurities in the range of 80-200 nm beneath the surface at room temperature. After helium ion implantation, the surface morphology has been greatly changed. In addition, two broad absorption bands at 360 nm and 780 nm are observed and their intensities significantly increase. An infrared band shifts from 782 cm^{-1 to 760 cm-1 and the band obviously broadens. Moreover, a luminescence band at 330 nm (3.8 eV) is associated with the 2P→1S* transition of the F+ centers. After laser irradiation, the laser damage morphologies of samples before and after ion implantation are presented. An obvious degradation of laser induced damage threshold (LIDT) is observed and the mechanism for the degradation of LIDT is discussed.}

8 illus, 32 ref

006328   Vidyarthi P K;Singh P K (Physics Dep, Institute of Basic Sciences, Dr B R Ambedkar Univ, Khandari Campus, Agra-282 004, Email: pramod0002000@yahoo.com) : Empirical relationships between thermoelastic parameters. Indian J pure appl Phys 2016, 54(7), 449-52.

The knowledge gained recently from the thermodynamic constraints for materials at infinite pressure or extreme compression has been used in the present work to obtain empirical relationships between thermoelastic properties. The variations in thermal expansivity with the change in pressure are found to be related with the changes in the second-order Gruneisen parameter. This has been demonstrated by using the results based on the seismic data for the Earth lower mantle. It is also found that the variations in thermoelastic properties with pressure are represented well in terms of the bulk modulus and its pressure derivative based on the Stacey reciprocal K-primed equation of state. The melting temperatures for hcp iron at different pressures are found to be related with the Debye temperatures at the corresponding pressures.

5 illus, 22 ref

006327   Venetis J C;Sideridis E P (NO, National Technical Univ of Athens, Greece, Email: siderem@mail.ntuga.gr) : Mathematical model for thermal conductivity of homogeneous composite materials. Indian J pure appl Phys 2016, 54(5), 313-20.

In this paper, a mathematical model to find the thermal conductivity of a large category of polymer homogeneous composite materials is performed. This type of composites contains ideal spherical particles encircled by an inhomogeneous interphase region, whereas the matrix is considered as isotropic. The thermal conductivity of the interphase is formulated as a continuous single-valued function of the radius of a spherical model. In this context, it is evident that the concept of boundary interphase is a useful manner for a quantitative description of the adhesion efficiency between matrix and filler since it is well known that there is a considerable effect of this phase on the thermo-mechanical properties of the composite. On the other hand, the particle distribution which can be considered as the influence of neighboring particles and their possible interaction should affect the thermal conductivity of the overall material.

3 illus, 34 ref

006326   Singh V P;Badiger N M (Physics Dep, Karnatak Univ, Dharwad-580 003, Email: kudphyvps@rediffmail.com) : Investigation on gamma and neutron shielding efficiency of lead-free compounds and alloys. Indian J pure appl Phys 2016, 54(7), 443-8.

The effective atomic numbers, Z_Pleff and half value layer, HVL for lead-free shielding materials, tungsten compounds and alloys for gamma ray over an energy range from 1 keV to 100 GeV have been calculated in the present work. As well as the macroscopic effective removal cross-sections (Σ_R) for fast neutron (2-12 MeV) had been calculated. From results, it has been concluded that HVL and Σ_R values of the tungsten alloys are half of the lead shielding material. The values of Z_Pleff have been compared with possible experimental results, and good agreement has been observed. We found that the theoretical values of Z_Pleff of the tungsten alloys agree with experiment where the ratio of atomic number of the elements is near to unity and shows weak energy dependence for ratio away from unity. The tungsten alloys show better the degree of protection against gamma ray and neutron as compared to the lead, resulting in an overall reduction in thickness and volume of the shielding material. The tungsten alloys containing gold, silver, platinum, copper, nickel and iron were found superior lead-free radiation shielding materials. This study is expected to be useful for design and application of lead-free radiation shielding for nuclear engineering, radiation application to control lead hazard.

2 illus, 3 tables, 28 ref

006325   Singh V P;Badiger N M (Physics Dep, Karnatak Univ, Dharwad-580 003, Email: kudphyvps@rediffmail.com) : Effective atomic numbers of dosimetric interest organic compounds. Indian J pure appl Phys 2016, 54(5), 333-8.

Effective atomic numbers of some dosimetric interest organic compounds, like glucose, ethanol, acetic acid, trichloroethylene, chloroform, benzene, acetone, phenol, chlorobenzene, naphthalene, adenine, alanine, anthracene, carbon tetrachloride, diethyl either and sucrose are calculated using Auto-Z_eff, direct, logarithmic interpolation, ratio, power law and single-value XmuDat methods. The calculated effective atomic numbers are compared with experiment data wherever possible and results show a good agreement. The Auto-Z_eff, direct, logarithmic interpolation and ratio methods are the most suitable for intermediate photon energy (50 keV <60> E <60> 20 MeV), where Compton scattering dominates. Mixture law is applicable in intermediate energy region for computation of theoretical effective atomic numbers. Kerma relative to air of the selected organic compounds are also calculated for photon energy 1 keV - 20 MeV. The kerma reaches unity beyond 200 keV and up to 10 MeV.

4 illus, 1 table, 25 ref

006324   Singh R;Verma U P;Singh A K (Physics Dep, Lucknow Univ, Lucknow-226 007) : Exploring middle atmosphere (D - region) by very low frequency (VLF) waves. Int J latest Technol Engng Mgmt appl Sci 2016, 5(6), 51-5.

Naturally occurring radio signals from terrestrial lightning discharges produce weeks that can be potentially used in the diagnostic of middle atmosphere specially D-region because of its ability to propagate into the region. In the present study we have observed tweeks throughout in the month of July, 2012and have used as a tool in the estimation of medium parameters such electron density and ionospheric reflection height. D-region electron density estimated from cut-off frequencies of different modes ranged from 22.51 - 132.46 cm-3. The ionospheric reflection height varied from 80 - 94.4 km. The existing time of tweeks was found to be in the range of 10 - 55 milliseconds. We have also tried to interpret the relation between cut-off frequency and relative amplitude of tweeks.

6 illus, 16 ref

006323   Singh D;Pathak P P (Physics Dep, Gurkul Kangri Univ, Haridwar, Email: drdevendrasingh@gmail.com) : Wound closure under the influence of DC field. Envir Conserv J 2016, 17(1-2), 13-15.

A possible mechanism of wound closure by direct current (DC) field is studied. DC stimulation reduces the surface area of a wound more rapidly in comparison to the other stimulations (Reger et al. 1999). It orients new collagen formation even in the absence of neural influences. Such type of stimulation enhances the tissue perfusion in the early phase of healing more significantly.

23 ref

006322   Shelar R N;Patil A V;Dighavkar C G;Borse R Y (Physics Dep, L V H College, Panchavati, Nashik-422 003, Email: rajnshelar@gmail.com) : Volumetric, viscometric and spectroscopic investigations of binary mixtures of o-chlorophenol with ethers. Indian J pure appl Phys 2016, 54(7), 463-70.

Density and viscosity of o-chlorophenol with tetrahydrofuran, diphenyl ether and tertbutylmethyl ether at different temperatures and at atmospheric pressure and spectroscopic study at atmospheric temperature and pressure have been measured experimentally. The excess molar volumes and deviation in viscosities have been calculated across the mole composition and interpreted for the intra and intermolecular association among like and unlike molecules. The influence of structure of components on the existing interaction has been revealed by the behavior of the excess parameters. The sign and magnitude of excess parameters clearly indicates the presence of specific interactions among the components. These parameters have been studied on the basis of dipole-dipole interaction and hydrogen bonding. The molecular structure and vibrational spectra have been investigated by Density Functional Theory (DFT) using standard B3LYP functional and 6-31G (d, p) basis set. Computed values at DFT (B3LYP)/6-31G (d, p) have been analyzed and their characterization has been made with the help of Gauss view visualization program utilizing the data obtained from the Gaussian 03 calculation.

3 illus, 9 tables, 37 ref

006321   Rani V;Ramesh C;Srivastava C;Zaidi M G H (Physics Dep, G.B. Pant Univ of Agriculture & Technology Pantnagar, Uttarakhand-263 145, Email: vershachuhan31@gmail.com) : Non isothermal decomposition and thermodynamics of magnetite nanoparticles. Int J Sci Nat 2016, 7(3), 537-40.

Magnetite nanoparticles were synthesized by using chemical co-precipitation method. Structural properties were studied by X-ray diffraction. Non isothermal kinetics of solid state decomposition of magnetite nanoparticles was studied under air atmosphere using thermo gravimetric analysis (TGA) in the temperature range (25°C-1000°C). In the present study the data was analyzed using various solid state reaction models. Integral method using Coats-Redfern and Horowitz-Metzger equations were applied in dynamic data analysis. The activation energy (E*), frequency factor (A), change in Entropy (ΔS), change in Enthalpy (ΔH) and change in Gibbs free energy (ΔF) for magnetite nanoparticles were evaluated. It was found that magnetite nanoparticles show one step decomposition behavior. Results indicate that the thermal activation energy of magnetite nanoparticles vary between the ranges of values 15-23 KJmol^-1.

18 ref

006320   Porwal V;Dixit A;Mamgain A K;Mishra S K;Gupta A K (Adaptive Optics Div, Instruments Research & Development Establishment, Defence Research & D, Dehradun-248 007, Email: skmishra@irde.drdo.in) : Systematic performance evaluation of indigenously developed Shack-Hartmann wavefront sensor. Indian J pure appl Phys 2016, 54(7), 419-26.

Shack-Hartmann wavefront sensor (SH-WS) is the key subsystem of an adaptive optical system (AOS). The systematic performance evaluation is the prerequisite for the optimal utilization of SH-WS in AOS. This requires generation and sensing of pure (Zernike modes) and random aberrations in laboratory. The Zernike modes, tilt and defocus are generated in the laboratory through a simple experimental arrangement. Other Zernike modes astigmatism, coma, spherical aberration, and trefoil are generated through a phase-only spatial light modulator. The random wavefront errors have been generated through indoor convective turbulence. Further, the aberrated wavefronts have been sensed by SH-WS and calibrated standard methods, simultaneously. The recorded data is analyzed to estimate the performance parameters, which are discussed in terms of calibration, accuracy, precision, response of various Zernike modes, and sensing of indoor convective turbulence.

12 illus, 3 tables, 22 ref

006319   Naveen Kumar;Sharma J D;Ahluwalia P K (Physics Dep, Shoolini Univ, Bajhol, Solan-173 212, Email: naveenattri83@gmail.com) : Ab initio calculation of electron transport in armchair graphane nano structure containing graphene quantum dot. Indian J pure appl Phys 2016, 54(7), 427-30.

First principle quantum transport calculations have been performed for armchair graphane nano structures containing graphene quantum dots (QD) of increasing sizes. Each QD has been formed by creating vacancies in the H lattice of graphane. TranSIESTA has been used for calculating transport properties with nonequilibrium Green's function approach within density functional theory. Transmission functions, electron density of states and current-voltage characteristics have been calculated using graphene electrodes. Band structure, electron density of states and zero bias conductance (transmission function) have been found to be in consonance with each other. The current in V-I characteristics shows non linear fluctuating pattern and tends to saturate as the voltage is increased. The value of current is graphene QD size dependent. The current lies in the range of nano ampere (for QD consisting of 16 contiguous vacancies) to femto ampere (for QD consisting of 6 contiguous vacancies).

4 illus, 1 table, 31 ref

006318   Nanda B (Thermo Acoustic Research Laboratory, Chemistry Dep, Dhaneswar Rath Institute of Engineering and Management Studies, Tangi, Cuttack-754 022, Email: bbnanda.driems@gmail.com) : Determination of available volume using thermo acoustical parameters and evaluation of ion-solvent interactions in liquid solutions. Indian J pure appl Phys 2016, 54(7), 471-5.

The available volume in a binary liquid mixture containing BaCl₂ and BaBr₂ at varying mole fraction of solute has been computed applying thermo acoustical parameters and ultrasonic method, a relation of the available volume. The relative applicability of all these approaches to the present investigation has been checked and discussed. The values obtained from both the methods are utilized to study the presence and strength of ion-solvent interactions of BaCl₂ and BaBr₂ with methanol-water, ethanol-water and dioxane-water system under investigation. The increase in the available volume indicates the presence of ion-solvent interactions as well as structure making ability of barium chloride and barium bromide in aqueous methanol, ethanol and dioxane solutions.

3 illus, 2 tables, 18 ref

006317   Mohan H;Pardeep Kumar;Sada Ram (NO, , ) : Modified double-diffusive convection in viscoelstic fluid. J expl appl Mech 2016, 7(1), 39-50.

Modified double-diffusive convection in viscoelastic fluid of the Veronis' and Stern's type configurations is considered in the present paper. Semi-circle theorems that prescribe upper limits for the complex growth rate of oscillatory motions of neutral or growing amplitude are derived. The limits so derived naturally culminate in sufficient conditions which precludes the non-existence of such motions. The results obtained herein significantly improve upon the earlier results derived in this direction.

ref

006316   Mhaisagar Y S;Gaikwad A S;Khairnar A G; Mahajan A M (Materials and Devices Laboratory for Nanoelectronics, Electronics Dep, North Maharashtra Univ, Jalgaon-425 001, Email: ammahajan@nmu.ac.in) : Enhancement in mechanical properties of silica low-k thin films using wet chemical tecnhique. Indian J pure appl Phys 2016, 54(7), 439-42.

Silica low-k films have been deposited on silicon wafer using sol-gel spin-on method. The tetraethyl orthosilicate (TEOS) has been used as a precursor solution. In order to improve the properties, the deposited films have been surface treated by wet chemical treatment at different trimethylcholosilane (TMCS) volumetric concentrations in hexane. The presence of hydrophobic (CH3) groups observed around 2900 cm^{-1 confirms the surface modification of films. Further, the water contact angle of as-deposited and surface treated film at 20% TMCS concentration in hexane have been found to be 83° to 104°, respectively. This significant change in water contact angle after surface modification confirmed the change in surface of film from hydrophilic to hydrophobic. The mechanical properties of films have been determined by using nano-indentation techniques. The depth of penetration of indent in film surface has been observed to be decrease from 75 nm to 45 nm after surface modification at 20% TMCS concentration in hexane. This shows the improvement in mechanical properties of film after surface modification. The Young's modulus and hardness of surface modified films at 20% TMCS have been observed to be 78 GPa and 3.45 GPa, respectively.}

5 illus, 13 ref

006315   Khanday F A;Psychalinos C (Electronics and Instrumentation Technology Dep, Kashmir Univ, Srinagar-190 006, Email: farooqsnn20@yahoo.co.in) : Realization of square-root domain integrators with large time-constant. Indian J pure appl Phys 2016, 54(5), 321-6.

A technique for performing capacitor scaling in Square-Root Domain (SRD) filters is introduced in this paper. This has been achieved through an appropriate modification of the bias in the corresponding SRD integrator blocks. The validity of the proposed scheme has been verified through simulation results, where the most important performance factors have been compared with those obtained through the conventional SRD integrator scheme.

8 illus, 2 tables, 20 ref

006314   Jeice A R;Wilson K S J (Physics Dep, Annai Velankannai College, Tholayavattam-629 157, Email: wilsonpra@yahoo.co.in) : Hydrostatic pressure and polaronic effects on the confined energies in a spherical quantum dot. Indian J pure appl Phys 2016, 54(7), 431-8.

The confined energies of low lying 1s, 1p and 1d states of an electron in a spherical quantum dot have been found out with finite barrier. The effects of hydrostatic pressure on various barrier heights have also been found. The influence of polaronic effects has been analyzed. The results show that the confined energies decrease as the dot size increases, the effect of hydrostatic pressure and polaronic mass decrease the confined energy, and the combined effect of hydrostatic pressure and polaronic reduce the confinement to 12% and 22% for 1s, 1p and 1d states, respectively. The results are also in good agreement with the other research articles in the literature.

5 illus, 5 tables, 31 ref

006313   George P M;Shubhashree N S;Divya P;Sreekuttan Unnithan C (Physics Dep, Dr. M.G.R Educational & Research Institute Univ, Chennai, Email: preethageoti@gmail.com) : Study of acoustical and physico chemical parameters of ground water in Chennai. Pollut Res 2016, 35(3), 605-7.

The aim of the present study is to assess the acoustical and physico chemical parameters of ground water in Chennai. The water samples were collected from houses of Ambathur and Vadapalani. Ultrasonic velocity (u), density (θ), and viscosity (μ) of drinking water samples were measured at 303K. Ultrasonic velocity has been measured using single frequency interferometer at 2MHz. From the experimental data other thermodynamics parameters, viz a diabatic the experimental data other thermodynamic parameters, viz adiabatic compressibility, intermolecular free length and acoustic impedance are calculated. Various Physico chemical parameters were also studied and compared with standard values.

2 tables, 5 ref