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 Subjects -> CHEMISTRY (Total: 767 journals)     - ANALYTICAL CHEMISTRY (45 journals)    - CHEMISTRY (532 journals)    - CRYSTALLOGRAPHY (22 journals)    - ELECTROCHEMISTRY (24 journals)    - INORGANIC CHEMISTRY (40 journals)    - ORGANIC CHEMISTRY (40 journals)    - PHYSICAL CHEMISTRY (64 journals) CHEMISTRY (532 journals)                  1 2 3 4 5 6 | Last
 Biointerface Research in Applied Chemistry    [3 followers]  Follow      Open Access journal      ISSN (Print) 2069-5837      Published by Comporter SRL  [2 journals]
• Anisotropic Bianchi type-III perfect fluid cosmological models in        class="a-plus-plus">f(       class="a-plus-plus">R,        class="a-plus-plus">T) theory of gravity

• Abstract: Abstract Einstein’s field equations are considered for spatially homogeneous and anisotropic Bianchi type-III space–time in presence of a perfect fluid within the framework of f(R, T) theory of gravity. Algorithms are derived to generate new classes of solutions of field equations starting from known solutions to the same type. Starting with the solution of Reddy and coworkers, new classes of Bianchi type-III cosmological models in f(R, T) gravity theory are generated. Kinematical and physical behaviors of the cosmological models are discussed. These models may be physically significant for discussion on early stages of evolution of the universe.
PubDate: 2013-12-01

• Dependence of solar mixing angle on CP violating phase        class="a-plus-plus">δ under deviation from
tri-bimaximal mixing

• Abstract: Abstract We deviate tri-bimaximal neutrino mixing with the help of charged lepton mixing matrix U lL which has a structure similar to that of Cabibbo–Kobayashi–Maskawa (CKM) matrix. To enter CP violating phase δ into rotation matrix, we follow a novel method discussed by Fritzsch and Xing which is different from the standard particle data group one. Under such charged lepton correction ansatz we note that $\tan^2 \theta_{12}$ becomes dependent on δ, from where constraints on δ phase can be obtained after employing experimental range of mixing angles. To compute numerical values of mixing angles we employ Wolfenstein parameterization of CKM matrix. We discuss implication of dependence of the physical observable parameters of neutrino oscillation on the choice of type of parameterization of the matrix.
PubDate: 2013-12-01

• Three dimensional peristaltic flow of Williamson fluid in a rectangular
duct

• Abstract: Abstract In present article, three dimensional peristaltic flow of a Williamson fluid model in rectangular channel has been discussed. The flow is unsteady and caused by propagation of sinusoidal waves due to peristaltic pumping. The equations of motion are derived for constitutive relation of Williamson model and are finally simplified under restrictions of low Reynolds number and long wavelength. The highly nonlinear and nonhomogeneous partial differential equations are solved by using homotopy perturbation method with combination of eigen function expansion method. The expression for pressure rise is found numerically. The final calculations for velocity, pressure gradient, pressure rise and stream functions are narrated graphically.
PubDate: 2013-12-01

• Optical properties of green synthesized ZnO nanocomposites

• Abstract: Abstract A green synthesis route using starch as a capping agent was effectively employed to synthesize ZnO nanostructures through chemical bath deposition. Sodium borohydride was used in one of the approaches in synthesis. Broadening of X-ray diffraction peaks suggested formation of nanosize ZnO in agreement with the high resolution transmission electron microscopy images. As-synthesized ZnO nanostructures were polycrystalline having wurtzite type structure. Average size of the particles was about 8 nm which was in close agreement with measurements from optical studies. Starch was found to play a key role in bringing the strong quantum confinement in ZnO particles. Optical absorption edge was found to be around 240–275 nm which exhibited a clear large blue shift and thereby enhancement of band gap energy. A strong green photoluminescence emission at 604.5 nm was observed in ZnO nanoparticles synthesized using sodium borohydride and may be attributed to the defect controlled recombination mechanism.
PubDate: 2013-12-01

• Influence of composition on structural, electrical and optical
characterizations of Bi       class="a-plus-plus">48−       class="a-plus-plus">x Sb       class="a-plus-plus">        class="a-plus-plus">x Se       class="a-plus-plus">52 ternary chalcogenide
system

• Abstract: Abstract Polycrystalline alloys of Bi48−x Sb x Se52 (where x = 0.6, 25, 35 and 44 at.%) were prepared by direct monotemperature technique. The surface morphology, crystalline nature and compositional analysis were studied using scanning electron microscopy, X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX), respectively. The XRD patterns recorded for the Bi48−x Sb x Se52 showed that these materials were polycrystalline in nature. Compositional analysis by EDX technique confirmed the nearly stoichiometric structure for the prepared alloys. The dielectric properties of the samples were investigated in the frequency range (102–105 Hz). The optical measurements revealed that the Bi48−x Sb x Se52 alloys were direct band gap semiconductors. The activation energy and optical band gap were found to increase with increasing Sb concentration in Bi48−x Sb x Se52.
PubDate: 2013-12-01

• Exact analytical versus numerical solutions of Schrödinger equation
for Hua plus modified Eckart potential

• Abstract: Abstract In this paper, s-wave Schrödinger equation with Hua plus modified Eckart potential is investigated. The eigenfunctions as well as energy eigenvalues are obtained in an exact analytical manner and compared with results obtained from finite difference method. Some special cases of this potential are also studied.
PubDate: 2013-12-01

• Studies on mechanical properties of titanium aluminium nitride coatings

• Abstract: Abstract Vickers and Knoop microhardness studies have been carried out on titanium aluminium nitride (TiAlN) hard coatings deposited on WC-12Co substrates. The microhardness test has been studied as a function of applied loads varying from 0.49 to 9.8 N. The normal indentation size effect has been observed in Vickers and Knoop microhardness test. It follows that increase in microhardness at lower loads (up to 9.8 N) depends inversely on elastic modulus of the hard coatings. Knoop microhardness test shows that microhardness values decrease with increase in applied load. The elastic stiffness constants have been calculated using Wooster’s empirical relation. Young’s modulus is found to be 378.18 GPa. Also hardness anisotropy has been performed with respect to the orientation of the TiAlN coatings from Knoop microhardness test. Morphology of indented imprints of the coatings has been examined using scanning electron microscopy.
PubDate: 2013-12-01

• Characteristics of compound multiplicity in        class="a-plus-plus">84Kr       class="a-plus-plus">36 with various light and
heavy targets at 1 GeV per nucleon

• Abstract: Abstract Interactions of 84Kr36 having kinetic energy around 1 GeV per nucleon with NIKFI BR-2 nuclear emulsion detector’s target reveal some of the important features of compound multiplicity. Present article shows that width of compound multiplicity distributions and value of mean compound multiplicity have linear relationship with mass number of the projectile colliding system.
PubDate: 2013-12-01

• Physical properties of MgSe thin films grown by chemical bath deposition
method: effect of molar concentration of MgCl       class="a-plus-plus">2

• Abstract: Abstract In the present paper, we have reported the effect of molar concentration of Mg salt on physical properties of MgSe thin films deposited by chemical bath deposition process. The MgSe thin films have been characterized for their structural, morphological and optical studies. We have observed that the films are nanocrystalline in nature with cubic lattice. The optical band gap energy of MgSe is changed from 2.82 to 2.65 eV depending on Mg ion concentration in deposition bath. The electrical resistivity of MgSe film varies from 56 × 102 to 41 × 102 Ω cm depending on Mg ion concentration in reaction bath. The thermo-emf measurement has confirmed p-type conductivity of MgSe.
PubDate: 2013-12-01

• Tunnel magnetoresistance of molecular junctions: endohedral fullerenes

• Abstract: Abstract In this paper, the spin-polarized electron transport through a $Ca^{2 + } @C_{N}$ (N = 60 and 70) molecule coupled to magnetic contacts has been studied theoretically. Our focus is on how displacement and movement direction of ion inside the cage and cage type affect on tunnel magnetoresistance (TMR) ratios of $Ca^{2 + } @C_{60}$ and $Ca^{2 + } @C_{70}$ molecules. Changes in displacement and movement direction of ion inside the cage can lead to changes in sign of TMR. TMR ratios in $Ca^{2 + } @C_{N}$ molecules vary from 60 to −40 % corresponding to the cage type and displacement and movement direction of the ion inside cage.
PubDate: 2013-12-01

• Ultrasonic measurements for Al alloy under quasi-hydrostatic pressure

• Abstract: Abstract The sound velocities of longitudinal and transverse waves of LY12Al are measured under quasi-hydrostatic pressure in a six-side anvil cell using pulse echo overlap technique. From measured sound velocities, the calculated adiabatic bulk modulus is 76.32 GPa. The results are found to be higher than the data obtained under low hydrostatic pressure. The reasons for the differences are analyzed. Different sample assemblies are also considered.
PubDate: 2013-12-01

• Study of molecular interactions in binary mixtures of
2-chloro-4′methoxy benzoin with various solvents through ultrasonic
speed measurements

• Abstract: Abstract Density (ρ) and ultrasonic velocity (U), for binary mixtures of 2-chloro-4′-methoxy benzoin with ethanol, chloroform, acetonitrile, benzene and 1,4-dioxane of different compositions have been measured at 298 K and explanation of solute solvent interactions and effect of polarity of the solvent on type of interactions are presented in this paper. From the above data, adiabatic compressibility (β), intermolecular free length (L f ) and relative association (R A ) have been calculated. Other useful parameters such as excess density, excess velocity, excess intermolecular freelength and excess adiabatic compressibility have also been calculated. These parameters have been used to study the nature and extent of intermolecular interactions between component molecules in present binary mixtures.
PubDate: 2013-12-01

• Analytical traveling wave and soliton solutions of the generalized
nonautonomous nonlinear Schrödinger equation with an external
potential

• Abstract: Abstract A class of analytical traveling wave and soliton solutions to generalized nonautonomous nonlinear Schrödinger equation with an external potential are constructed by using homogeneous balance principle and F-expansion technique. Constraint conditions for analytical solutions are obtained at the same time which admit different types of external potentials. Various types of analytical traveling waves and soliton solutions are studied in detail. Stability analysis of the solutions is discussed numerically. Results show that stable propagation of solitons can be maintained in nonuniform distributed nonlinear media.
PubDate: 2013-12-01

• Nonlinear analysis of dynamic signature

• Abstract: Abstract Signature is a long trained motor skill resulting in well combination of segments like strokes and loops. It is a physical manifestation of complex motor processes. The problem, generally stated, is that how relative simplicity in behavior emerges from considerable complexity of perception–action system that produces behavior within an infinitely variable biomechanical and environmental context. To solve this problem, we present evidences which indicate that motor control dynamic in signing process is a chaotic process. This chaotic dynamic may explain a richer array of time series behavior in motor skill of signature. Nonlinear analysis is a powerful approach and suitable tool which seeks for characterizing dynamical systems through concepts such as fractal dimension and Lyapunov exponent. As a result, they can be analyzed in both horizontal and vertical for time series of position and velocity. We observed from the results that noninteger values for the correlation dimension indicates low dimensional deterministic dynamics. This result could be confirmed by using surrogate data tests. We have also used time series to calculate the largest Lyapunov exponent and obtain a positive value. These results constitute significant evidence that signature data are outcome of chaos in a nonlinear dynamical system of motor control.
PubDate: 2013-12-01

• Topological solitons, cnoidal waves and conservation laws of coupled wave
equations

• Abstract: Abstract In this paper a few coupled wave equations that arise in the dynamics of two-layered shallow water waves in ocean shores and beaches have been studied. The mapping method is applied to extract cnoidal waves and solitary wave solutions to the coupled Korteweg–de Vries (KdV) equation, coupled Boussinesq equation and the coupled Whitham–Broer–Kaup equation. The ansatz method is also applied to obtain topological 1-solution to the coupled KdV equation with power law nonlinearity. The multiplier method then gives a few conserved quantities of the coupled KdV equation.
PubDate: 2013-12-01

• Structural studies on picolinium maleate crystal by density functional
methods

• Abstract: Abstract The optimized geometry and vibrational frequencies of picolinium maleate (PM), an organic non-linear optical material, was obtained by ab initio DFT/B3LYP level with complete relaxation in the potential energy surface using 6-311G(d,p) basis sets. The Fourier-transform infrared (FT-IR) spectrum of PM was recorded in the region 4,000–400 cm−1. The harmonic vibrational frequencies were calculated and scaled values had been compared with experimental FT-IR spectrum. The optical non-linearity arose from intermolecular hydrogen bonding between centro-symmetric picolinic acid and maleic acid. The DFT study was aimed at identifying intermolecular hydrogen bonding nature and comparing the calculated values with the XRD data. Analysis of experimental 13C shielding parameters was supported by DFT theoretical calculations carried out within the gauge-including atomic orbital and the spectra estimations were performed using ChemPro 8.0. It was found that chemical shifts obtained with ChemPro 8.0 were due to the substitution effects. The charge density distribution and site of chemical reactivity of molecules were obtained by mapping electron density isosurface with electrostatic potential surfaces. The scaled frequencies are comparable with the experimental frequencies. Energy span as calculated by ZINDO method, between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of PM is −8.9697 and −1.5477 eV.
PubDate: 2013-12-01

• Numerical solutions of Magnetohydrodynamic boundary layer flow of tangent
hyperbolic fluid towards a stretching sheet

• Abstract: Abstract In the present article, we have studied the two dimensional tangent hyperbolic fluid flow towards a stretching sheet with a magnetic field. Governing equations for the proposed model are modelled and then simplified using boundary layer approach and similarity transformations. Simplified governing equations are then solved numerically with the help of fourth and fifth order Runge–Kutta–Fehlberg method. Physical features of the involved parameters are presented and discussed.
PubDate: 2013-11-01

• Structural and optical properties of pure and Al doped ZnO nanocrystals

• Abstract: Abstract Pure and Al doped zinc oxide (ZnO) were prepared by co-precipitation method. The dopant concentration [Al/Zn in atomic percentage (wt%)] was varied from 0 to 3 wt%. Structural characterisation of the samples performed with XRD and SEM–EDAX confirmed that polycrystalline nature of samples containing ZnO nanoparticles of size in the range of 97–47 nm. UV–Vis studies showed that the absorbance peaks, observed in the wavelength range of 800–250 nm, decreased with the increase in dopant concentration indicating widening of the band gap. The calculations of band gap (analyzed in terms of Burstein–Moss shift) from the reflectance showed an increase from 3.37 to 3.49 eV with increasing Al concentration.
PubDate: 2013-11-01

• Density functional theory study of MnY       class="a-plus-plus">        class="a-plus-plus">N (       class="a-plus-plus">N = 2–13)
clusters

• Abstract: Abstract We predict that doped Mn atoms can not efficiently improve magnetism of yttrium clusters in most cases, which is different from Mn–Ge, Mn–Bi and Mn–B complexes. The calculated results show that the ground state structures of MnY N clusters favor growth patterns of octahedron structures, with Mn atom occupying the center of yttrium framework at N ≥ 6. There are three minima of the HOMO–LUMO gap with N = 6, 10 and 13 which can be mainly attributed to obvious elevation of energy level of the HOMO. The computed magnetic moment per atom displays size-dependent behavior with oscillational odd–even character. The Mulliken population analysis shows that the doped Mn atom, with antiferromagnetic alignment at N = 5, 9, 11 and 13, tends to reduce the magnetic moment of the system of N ≥ 6. Both structure and chemical bonding are responsible for the variation of magnetism of Mn doped yttrium clusters.
PubDate: 2013-11-01

• Transverse momentum distribution of particles in high energy collisions
and relativistic temperature transformation

• Abstract: Abstract Based on kinetic theory of ideal gas, the present work gives an indirect measurement on relativistic temperature transformation by using transverse momentum distribution of particles. Our result shows that Planck–Einstein relation is right. A moving system which has no energy current exchange with external surroundings becomes cool.
PubDate: 2013-11-01

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