013047   Padmanabhan G;Kumar R;Ulagendran V;Kannappan V;Jayakumar S (Physics Dep, Sri Sankara College, Kanchipuram-631 561, Email: sjayakumar5454@yahoo.com) : Molecular interaction studies of cinnamaldehyde with certain alcohols by ultrasonic method at 303.15 K. Indian J pure appl Phys 2012, 50(12), 899-906.

The results of a new experimental study of thermo physical properties for eight binary systems of cinnamaldehyde with different alkanols have been presented. Speed of ultrasound (u), density (p) and viscosity (η) at 303.15 K and atmospheric pressure have been measured over the whole range of composition. These properties have been used to calculate various thermo acoustical parameters. The variations in these parameters have been studied in terms of nature and extent of interaction and the effect of structure of alcohols on the existing interactions. The non-ideal behaviour of the binary systems has been revealed through the sign and magnitude of excess velocity, viscosity deviation and other excess parameters. These parameters have been studied on the basis of dipole-dipole interactions and hydrogen bonding. The excess parameters have been fitted to polynomial type Redlich-Kister equation and the coefficients of the fitting have been found to support the present investigation.

2 illus, 4 tables, 40 ref

013046   Ozdemir Z G (Physics Dep, Yildiz Technical Univ, 34210 Esenler, Istanbul, Turkey, Email: zguvenozdemir@yahoo.com) : Schwarzian derivative as a proof of the chaotic behaviour. Pramana J Phys 2011, 77(6), 1159-69.

In recent years, a sufficient condition for determining chaotic behaviours of the nonlinear systems has been characterized by the negative Schwarzian derivative (Hacibekiroglu et al, Nonlinear Anal.: Real World Appl. 10, 1270 (2009)). In this work, the Schwarzian derivative has been calculated for investigating the quantum chaotic transition points in the high-temperature superconducting frame of reference, which is known as a nonlinear dynamical system that displays some macroscopic quantum effects. In our previous works, two quantum chaotic transition points of the critical transition temperature, T_c, and paramagnetic Meissner transition temperature, TPME. have been phenomenologically predicted for the mercury-based high-temperature superconductors (Onbash et al, Chaos, Solitons and Fractals 42, 1980 (2009); Asian et al, J. Phys.: Conf. Ser. 153, 012002 (2009); Cataltepe, Superconductor (Sciyo Company, India, 2010)). The T_c, at which the one-dimensional global gauge symmetry is spontaneously broken, refers to the second-order phase transition, whereas the TPME. at which time reversal symmetry is broken, indicates the change in the direction of orbital current in the system (Onbasli et al, Chaos, Solitons and Fractals 42, 1980 (2009)). In this context, the chaotic behaviour of the mercury-based high-temperature superconductors has been investigated by means of the Schwarzian derivative of the magnetic moment versus temperature. In all calculations, the Schwarzian derivatives have been found to be negative at both T_c and TPME which are in agreement with the chaotic behaviour of the system.

7 tabels, 33 ref

013045   Osman A (Physics Dep, Faculty of Science, Cairo Univ, Cairo, Egypt, Email: ahmedosman_1944@yahoo.com) : Quark model for kaon nucleon scattering. Pramana J Phys 2011, 77(6), 1069-78.

Kaon nucleon elastic scattering is studied using chiral SU(3) quark model including antiquarks. Parameters of the present model are essentially based on nucleon-nucleon and nucleon-hyperon interactions. The mass of the scalar meson a is taken as 635 MeV. Using this model, the phase shifts of the 5 and P partial waves of the kaon nucleon elastic scattering are investigated for isospins 0 and 1. The results of the numerical calculations of different partial waves are in good agreement with experimental data.

6 illus, 2 tables, 15 ref

013044   Narayanan R;Sekar Iyengar A N (Plasma Physics Div, Saha Institute of Nuclear Physics, I/AF Bidhannagar, Kolkata-700 064, Email: rams75apr@yahoo.co.in) : Negative edge plasma currents in the SINP tokamak. Pramana J Phys 2011, 77(6), 1135-49.

Tokamak plasma discharge having an increase in duration accompanied with enhanced runaway electron flux has been experimentally studied in this paper. The discharges have been obtained by controlling the applied vertical magnetic field (B_v^appl) to below a critical value. Such discharges have been observed to have 'negative edge plasma currents', detected using an internal Rogowskii coil (IRC) and tried to correlate the runaway behaviour with the negative edge plasma currents and have explained that these observations are a result of beam plasma instabilities.

10 illus, 22 ref

013043   Narain R;Kara A H (School of Mathematics and Centre for Differential Equations, Continuum Mechanics and Applications, Witwatersrand Univ, Johannesburg, Private Bag 3, Wits 2050, South Africa, Email: Abdul.Kara@wits.ac.za) : Invariance analysis and conservation laws of the wave equation on Vaidya manifolds. Pramana J Phys 2011, 77(3), 555-70.

In this paper authors discuss symmetries of classes of wave equations that arise as a consequence of some Vaidya metrics. Show how the wave equation is altered by the underlying geometry. In particular, a range of consequences on the form of the wave equation, the symmetries and number of conservation laws, inter alia, are altered by the manifold on which the model wave rests. Authors find Lie and Noether point symmetries of the corresponding wave equations and give some reductions. Some interesting physical conclusions relating to conservation laws such as energy, linear and angular momenta are also determined. Also presents some interesting comparisons with the standard wave equations on a flat geometry. Finally, authors pursue the existence of higher-order variational symmetries of equations on nonflat manifolds.

1 table, 10 ref

013042   Mathew B;Adebayo G A (Physics Dep, Agriculture Univ, Abeokuta, Nigeria, Email: bukkymatt4real@yahoo.com) : Adhesion energy, surface traction and surface tension in liquid xenon. Pramana J Phys 2011, 77(6), 1151-7.

Calculated the adhesion energy, the surface traction and the surface energy of liquid xenon using molecular dynamics (MD) simulation. The value of the adhesion energy for liquid xenon at a reduced density of 0.630 was found to be 0.591 J/m² and the surface traction has a peak at z = 3.32 A. It was observed that the attraction of the molecules in the liquid surface which produces a resistance to penetration decreases with temperature. This may be attributed to the greater average separation of molecules at higher temperature.

4 illus, 3 tables, 23 ref

013041   Mandal S;Ghosh A (Electronics & Communication Engineering Dep, B P Poddar Institute of Management & Technology, 137, V.I.P. Road, Kolkata-700 052, Email: surajitmandal@yahoo.co.in) : Effect of broadband illumination of the imaging characteriztics of a birefringent lens suffering from primary spherical aberration. J Optics 2011, 40(4), 198-205.

This report forms a part of the systematic investigation on the imaging behaviour of an optical system consisting of a lens made of a uniaxial birefringent crystal sandwiched between two linear polarizers into which primary spherical aberration is introduced. The optic axis of the birefringent crystal is perpendicular to the lens axis. The proposed system is illuminated with a polychromatic beam of light, the spectral profile of which is considered to be uniform for all wave lengths. The axial irradiance distribution function and the intensity point spread function are used as the image assessment parameters. Some specific cases are computed and illustrated graphically. The study reveals that if the variation of the birefringent parameters of the device with wavelength is less, a larger bandwidth may be used without considerably deviating from the imaging characteristics under strictly monochromatic illumination suffering from similar primary spherical aberration.

7 illus, 30 ref

013040   Manchanda K;Umeshkanta Singh T;Ramaswamy R (School of Physical Sciences, Jawaharlal Nehru Univ, New Delhi-110 067, Email: kaustubh011184@gmail.com) : Dynamics of excitable nodes on random graphs. Pramana J Phys 2011, 77(5), 803-9.

Study the interplay of topology and dynamics of excitable nodes on random networks. Comparison is made between systems grown by purely random (Erdos-Renyi) rules and those grown by the Achlioptas process. For a given size, the growth mechanism affects both the thresholds for the emergence of different structural features as well as the level of dynamical activity supported on the network.

3 illus, 21 ref

013039   Maharaj S D;Govender G;Govender M (Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Private Bag X54001, KwaZulu-Natal Univ, Durban 4000, South Africa, Email: maharaj@ukzn.ac.za) : Temperature evolution during dissipative collapse. Pramana J Phys 2011, 77(3), 469-76.

Investigate the gravitational collapse of a radiating sphere evolving into a final static configuration described by the interior Schwarzschild solution. The temperature profiles of this particular model are obtained within the framework of causal thermodynamics. The overall temperature evolution is enhanced by contributions from the temperature gradient induced by perturbations as well as relaxational effects within the stellar core.

1 illus, 16 ref

013038   Krishna Mohan T R;Sen S (NO, CSIR Centre for Mathematical Modelling and Computer Simulation (C-MMAC, NAL Wind Tunnel Road, Bangalore-560 037, Email: kmohan@cmmacs.ernet.in) : Linearity stabilizes discrete breathers. Pramana J Phys 2011, 77(5), 975-86.

Study of the dynamics of 1D chains with both harmonic and nonlinear interactions, as in the Fermi-Pasta-Ulam (FPU) and related problems, has played a central role in efforts to identify the broad consequences of nonlinearity in these systems. Study the dynamics of highly localized excitations, or discrete breathers, which are known to be initiated by the quasistatic stretching of bonds between adjacent particles. We show via dynamical simulations that acoustic waves introduced by the harmonic term stabilize the discrete breather by suppressing the breather's tendency to delocalize and disperse. We conclude that the harmonic term, and hence acoustic waves, are essential for the existence of localized breathers in these systems.

6 illus, 47 ref

013037   Krishan Lal (Indian National Science Academy, Bahadur Shah Zafar Marg, New Delhi-110 002, Email: klal@nplindia.org) : High resolution X-ray diffraction- a powerful technique to understand crystalline materials. Proc Indian Natn Sci Acad 2012, 78(1), 99-119.

Wide variety of materials are needed in advanced areas of Science & Technology as well as for meeting daily requirements of modern societies. For application in advanced areas as well as for fundamental understanding, one requires knowledge about relationship between the properties of the materials and their basic characteristics namely, composition, impurities, crystallographic structure and defects. High resolution X-ray diffraction techniques are widely used to investigate real structure of crystals, thin films, interfaces and devices. In this paper, basic elements of dynamical diffraction theory have been described. Essential features of a five crystal X-ray diffractometer designed and developed in author's laboratory are discussed. A new defect, very low angle boundaries, has been observed in bismuth germanate crystals. Typical results on direct imaging of dislocations in crystals have been presented. It has been shown that dynamical diffraction phenomena like forward diffracted X-ray beam and anomalous transmission of X-rays at diffraction maxima can be observed even with 'thin' crystals of varying degrees of perfection. This result is not expected on the basis of the usual dynamical diffraction theory. A theoretical analysis has shown that the presence of forward diffracted X-ray beam is implicit in the dynamical diffraction theory and the loss in absorption at Laue diffraction peaks in 'thin' crystals can be understood.

27 illus, 1 table, 27 ref

013036   Kolwankar K M;Ren Q;Samal A;Jost J (Physics Dep, Ramniranjan Jhunjhunwala College, Ghatkopar (W), Mumbai-400 086, Email: Kiran.Kolwankar@gmail.com) : Learning and structure of neuronal networks. Pramana J Phys 2011, 77(5), 817-26.

Study the effect of learning dynamics on network topology. Firstly, a network of discrete dynamical systems is considered for this purpose and the coupling strengths are made to evolve according to a temporal learning rule that is based on the paradigm of spike-time-dependent plasticity (STDP). This incorporates necessary competition between different edges. The final network obtain is robust and has a broad degree distribution. Then study the dynamics of the structure of a formal neural network. For properly chosen input signals, there exists a steady state with a residual network. Compare the motif profile of such a network with that of the real neural network of C. elegans and identify robust qualitative similarities. In particular, our extensive numerical simulations show that this STDP-driven resulting network is robust under variations of model parameters.

5 illus, 29 ref

013035   Khairnar R S;Mahabole M P;Pathak A P (School of Physical Science, SRTM Univ, Vishnupuri, Nanded-431 606, Email: rk2kin@yahoo.com) : Nanoactivator mediated modifications in thermostable amylase from Bacillus licheniformis. Indian J Biochem Biophys 2012, 49(6), 468-71.

Gram-positive rod-shaped thermophilic bacteria were isolated using samples collected from terrestrial natural thermal spring located at Unkeshwar (Longitude 78.22 degree East to 78.34 degree East, Latitude 19 degree 34' North to 19 degree 40' North), District Nanded, Maharashtra State, India. The isolates were then cultivated using selective media and identified using culture-dependent techniques. One prominent isolate (UNI) exhibited high temperature stability and remarkable amylase production and was identified as Bacillus licheniformis. Amylase production was carried out in starch media and the enzyme was partially purified and characterized for optimization of pH and temperature. Amylolytic activity of the enzyme was determined. Nanoactivator-mediated modifications were carried out to enhance amylolytic activity of the partially purified amylase. Three-fold increase in catalytic efficiency of amylase was obtained after modification.

^ssc4 illus, 15 ref

013034   Kachhvah A D;Gupte N (Physics Dep, Indian Institute of Technology Madras, Chennai-600 036, Email: ajay@physics.iitm.ac.in) : Avalanche transmission and critical behaviour in load-bearing hierarchial networks. Pramana J Phys 2011, 77(5), 873-9.

Strength and stability properties of hierarchical load-bearing networks and their strengthened variants have been discussed in a recent work. Here, study the avalanche time distributions on these load-bearing networks. The avalanche time distributions of the V-lattice, a unique realization of the networks, show power-law behaviour when tested with certain fractions of its trunk weights. All other avalanche distributions show Gaussian peaked behaviour. Thus the V-lattice is the critical case of the network. Also discuss the implications of this result.

6 illus, 11 ref

013033   Jabeen S;Mishra L K (Guest Faculty, Physics Dep, Jamshedpur Women's College, Bistupur, Jamshedpur, Jharkhand) : Evaluation of pseudo gap in high T_c-superconductors using pairing scenario of noziers and schmitt-rink theory. J pure appl ind Phys 2013, 3(2), 162-70.

In this paper, we have studied the Pseudo gap in high Tc-superconductors through pairing scenario based on Nozieres and Schmitt - Rink theory. The central theme of this theory is the Cross-over problem from BCS superconductivity to Bose-Einstein Condensation (BEC). Pseudo gap state is regarded as a cross-over region. There is a co-existence of fermions and bosons in this region. Evaluating the self-energy from T-matrix approach, we have studied the Pseudo gap in the single particle excitation. The spectral function clearly shows the Pseudo gap in the single particle spectrum which appears in the cross-over region.

3 tables, 40 ref

013032   Iyer B R (Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore-560 080, Email: bri@rri.res.in) : Gravitational waves from binary black holes. Pramana J Phys 2011, 77(1), 119-33.

It is almost a century since Einstein predicted the existence of gravitational waves as one of the consequences of his general theory of relativity. A brief historical overview including Chandrasekhar's contribution to the subject is first presented. The current status of the experimental search for gravitational waves and the attendant theoretical insights into the two-body problem in general relativity arising from computations of gravitational waves from binary black holes are then broadly reviewed.

3 illus, 51 ref

013031   Hsueh C C;Elazhary T;Nakano M;Sasian J (Mechanical Engineering Dep, National Cheng Kung Univ, Tainan-70101, Taiwan, Email: n1896134@mail.ncku.edu.tw) : Closed-form sag solutions for cartesian oval surfaces. J Optics 2011, 40(4), 168-75.

This paper presents a closed-form solution to the sag of the Cartesian oval and an alternate iterative method for obtaining the sag. The emphasis is in providing a methodology for determining the sag and derivatives of a Cartesian surface for optical design, ray-tracing purposes. We verify our results by comparison of our solutions and by real ray tracing.

6 illusm 1 table, 9 ref

013030   Hemalatha R;Sivapraba N (Mathematics Dep, Kanchi Mamunivar Centre for Post Graduate Studies, Puducherry-605 014, Email: hemalatha53@yahoo.co.in) : Effect of magnetic field dependent viscosity on ferroconvection in a sparsely distributed porous medium in the presence of horizontal thermal gradient. Indian J pure appl Phys 2012, 50(12), 907-14.

The effect of magnetic field dependent viscosity on ferroconvection subjected to two dimensional magnetic field in an anisotropic sparsely distributed porous medium has been analyzed. The fluid layer is assumed to be bounded by free boundaries. The exact solution of constitutive equation is derived using linear theory. Wide range of values of the ratio of horizontal, vertical temperature gradient, anisotropic parameter, permeability of the porous medium, coefficient of magnetic dependent viscosity and the magnetization parameter have been considered. The system is found to stabilize only through stationary mode of instability. It is also seen that oscillatory instability cannot occur.

11 illus, 37 ref

013029   Gurefe Y;Sonmezoglu A;Misirli E (Mathematics Dep, Faculty of Science, Bozok Univ, 66100 Yozgat, Turkey, Email: yusuf.gurefe@bozok.edu.tr) : Application of the trial equation method for solving some nonlinear evolution equations arising in mathematical physics. Pramana J Phys 2011, 77(6), 1023-9.

In this paper some exact solutions including soliton solutions for the KdV equation with dual power law nonlinearity and the K(m,n) equation with generalized evolution are obtained using the trial equation method. Also a more general trial equation method is proposed.

34 ref

013028   Guleria R P;Sharma N L (Physics Dep, Government Senior Secondary School Manali, District Kullu, Himachal Pradesh) : Efficiency of solar energy devices: cause and concern. J pure appl ind Phys 2013, 3(2), 102-9.

Present experimental study carried out in the Manali town, where all the solar panels positioned on a fixed surface with its face towards south at an elevation angle of 45°. They do not track the Sun and therefore, the efficiency of power generation is low. Also proposed two axis solar tracker to ensures the maximum conversion of solar energy into electricity. Experimental investigation shows that using solar tracker the power generation can be increased by 45% as compared to a fixed PV module. The proposed measurement system provides a valuable contribution to the technologists who are working on the development of tracking systems in the solar energy technology field. The results obtained on the experimental site achieved a 53.8% gain in energy production, which reveals that the solar tracking system is able to deliver high power and a better conversion efficiency compared to a fixed module inclined 45° at the same latitude.

5 illus, 3 tables, 10 ref

013027   Guha P;Choudhary A G (NO, S.N. Bose National Centre for Basic Sciences, J D Block, Sector III, Salt Lake, Kolkata-700 098, Email: partha@bose.res.in) : Role of the Jacobi last multiplier and isochrobous systems. Pramana J Phys 2011, 77(5), 917-27.

Employ Jacobi's last multiplier (JLM) to study planar differential systems. In particular, examine its role in the transformation of the temporal variable for a system of ODEs originally analysed by Calogero-Leyvraz in course of their identification of isochronous systems. Also show that JLM simplifies to a great extent the proofs of isochronicity for the Lienard-type equations.

15 ref

013026   Goswami B K (Laser and Plasma Technology Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: binoy@barc.gov.in ) : Flip-flop between soft-spring and hard-spring bistabilities in the approximated toda oscillator analysis. Pramana J Phys 2011, 77(5), 987-1005.

Study theoretically the effect of truncating the nonlinear restoring force (exp(Φ) - 1 = Σ_n=1^∞ = Φⁿ/n in the bistability pattern of the periodically driven, damped one-degree-of-freedom Toda oscillator that originally exhibits soft-spring bistability with counterclockwise hysteresis cycle. Observes that if the truncation is made third order, the harmonic bistability changes to hard-spring type with a clockwise hysteresis cycle. In contrast, for the fourth-order truncation, the bistability again becomes soft-spring type, overriding the effect of third-order nonlinearity. Furthermore, each higher odd-order truncation attempts to introduce hard-spring nature while each even-order truncation turns to soft-spring type of bistability. Overall, the hard-spring effect of every odd-order nonlinear term is weaker in comparison to the soft-spring effect of the next even-order nonlinear term. As a consequence, higher-order approximations ultimately converge to the soft-spring nature. Similar approximate analysis of Toda lattice has in recent past revealed remarkably similar flip-flop pattern between stochasticity (chaotic behaviour) and regularity (integrability).

5 illus, 15 ref

013025   Ghosh D;Deb A;Bhattacharyya S;Datta U (Physics Dep, Nuclear and Particle Physics Research Centre, Jadavpur Univ, Kolkata-700 032, Email: swarna_pratim@yahoo.com) : Rapidity dependence of multiplicity fluctuations and correlations in high-energy nucleus-nucleus interactions. Pramana J Phys 2011, 77(2), 297-313.

Multiplicity fluctuations of the produced pions were studied using scaled variance method in ¹⁶O-AgBr interactions at 2.1 AGeV, ²⁴Mg-AgBr interactions at 4.5AGeV, ¹²C-AgBr interactions at 4.5 AGeV, ¹⁶O-AgBr interactions at 60 AGeV and ³²S-AgBr interactions at 200 AGeV at two different binning conditions. In the first binning condition, the rapidity interval was varied in steps of one centring about the central rapidity until it reached 14. In the second case, the rapidity interval was increased in steps of 1.6 up to 14.4. Multiplicity distributions and their scaled variances were presented as a function of the dependence on the rapidity width for both the binning conditions. Multiplicity fluctuations were found to increase with the increase of rapidity interval and later found to saturate at larger rapidity window for all the interactions and in both the binning conditions. Multiplicity fluctuations were found to increase with the energy of the projectile beam. The values of the scaled variances were found to be greater than one in all the cases in both the binning conditions indicating the presence of correlation during the multiparticle production process in high-energy nucleus-nucleus interactions. Experimental results were compared with the results obtained from the Monte Carlo simulated events for all the interactions. The Monte Carlo simulated data showed very small values of scaled variance suggesting very small fluctuations for the simulated events. Experimental results obtained from ¹⁶O-AgBr interactions at 60 AGeV and ³²S-AgBr interactions at 200 AGeV were compared with the events generated by Lund Monte Carlo code (FRITIOF model). FRITIOF model failed to explain the multiplicity fluctuations of pions emitted from ¹⁶O-AgBr interactions at 60 AGeV for both the binning conditions. However, the experimental data agreed well with the FRITIOF model for ³²S-AgBr interactions at 200 AGeV.

15 illus, 8 tables, 23 ref

013024   Ghaderi A;Elahi S M;Solaymani S;Naseri M; Ahmadirad M;Bahrami S;Khalili A E (Physics Dep, Islamic Azad Univ, Tehran Central Branch, Tehran, Iran, Email: atefeh.ghaderi@gmail.com) : Thickness dependence of the structural and electtrical properties of ZnO thermal-evaporated thin films. Pramana J Phys 2011, 77(6), 1171-8.

ZnO thin films of different thicknesses were prepared by thermal evaporation on glass substrates at room temperature. Deposition process was carried out in a vapour pressure of about 5.54 x 10^-5 mbar. The substrate-target distance was kept constant during the process. By XRD and AFM techniques the microstructural characteristics and their changes with variation in thickness were studied. Electrical resistivity and conductivity of samples vs. temperature were investigated by four-probe method. It was shown that an increase in thickness causes a decrease in activation energy.

5 illus, 3 tables, 19 ref

013023   Garg I;Deo N (Physics & Astrophysics Dep, Delhi Univ, Delhi-110 007, Email: ndeo@physics.du.ac.in) : Matrix models of RNA with external interactions. Pramana J Phys 2011, 77(5), 827-32.

Matrix model of (simplified) RNA folding with an external linear interaction in the action of the partition function is reviewed. The important results for structure combinatorics of the model are discussed and analysed in terms of the already existing models.

^iia15 ref

013022   Ganguly S;Banerjee P;Dey A;Bhattacharya S (Physics Dep, Chandernagore College, Chandernagore, Hooghly-712 136, Email: sgpresi78@gmail.com) : Experimental study of the θh_11/2 band in <. Pramana J Phys 2011, 77(2), 277-87.

In the present work, the excited states of ¹¹³Sb were populated in the ¹⁰⁰Mo(²⁰Ne, p6n) reaction at a beam energy of 136 MeV. States only up to 59/2^- were observed in the ΔJ = 2 band. Mean lifetimes for the five states (from 4460 to 7998 keV) were measured for the first time using Doppler shift attenuation method. An upper limit of the lifetime (0.14 ps) was estimated for the 9061 keV, 47/2^- state. The B(E2) values, derived from the present lifetime results, correspond to a large quadrupole deformation of β₂ = 0.32. The observed reduction in the experimental B(E2) values for the 918.4 keV (spin 39/2^-→ 35/2^-) and 985 keV (spin 43/2^- → 39/2") transitions may be interpreted as due to the proton alignement in the g7/2 orbital. The dynamic moment of inertia was observed to be about half of the rigid body value at the highest observed frequency.

5 illus, 2 tables, 25 ref

013021   Flach S;Ivanchenko M;Li N (Max Planck Institut fur Physik Komplexer Systeme, , Nothnitzer Str. 38, 01187 Dresden, Germany, Email: flach@pks.mpg.de) : Thermal conductivity of nonlinear waves in disordered chains. Pramana J Phys 2011, 77(5), 1007-14.

Presents computational data on the thermal conductivity of nonlinear waves in disordered chains. Disorder induces Anderson localization for linear waves and results in a vanishing conductivity. Cubic nonlinearity restores normal conductivity, but with a strongly temperature-dependent conductivity K(T). Finds indications for an asymptotic low-temperature K <126> T⁴ and intermediate temperature K <126> T² laws. These findings are in accord with theoretical studies of wave packet spreading, where a regime of strong chaos is found to be intermediate, followed by an asymptotic regime of weak chaos (Laptyeva et al, Europhys. Lett. 91, 30001 (2010)).

3 illus, 21 ref

013020   Fakhar K;Zainal A A;Kara A H (Mathematics Dep, Faculty of Science, Teknologi Malaysia Univ, 81310 UTM Skudai, Johor, Malaysia) : Note on the interplay between symmetries, reduction and conservation laws of stokes' first problem for third-grade rotating fluids. Pramana J Phys 2011, 77(3), 439-45.

Investigates the invariance properties, nontrivial conservation laws and interplay between these notions that underly the equations governing Stokes' first problem for third-grade rotating fluids. We show that a knowledge of this leads to a number of different reductions of the governing equations and, thus, a number of exact solutions can be obtained and a spectrum of further analyses may be pursued.

1 table, 8 ref

013019   Duha S S;Shikha B;Mamun A A (Physics Dep, Jahangirnagar Univ, Savar, Dhaka-1342, Bangladesh, Email: shadab22@yahoo.com) : Nonlinear dust-ion-acoustic waves in a multi-ion plasma with trapped electrons. Pramana J Phys 2011, 77(2), 357-68.

A dusty multi-ion plasma system consisting of non-isothermal (trapped) electrons, Maxwellian (isothermal) light positive ions, warm heavy negative ions and extremely massive charge fluctuating stationary dust have been considered. The dust-ion-acoustic solitary and shock waves associated with negative ion dynamics, Maxwellian (isothermal) positive ions, trapped electrons and charge fluctuating stationary dust have been investigated by employing the reductive perturbation method. The basic features of such dust-ion-acoustic solitary and shock waves have been identified. The implications of our findings in space and laboratory dusty multi-ion plasmas are discussed.

7 illus, 50 ref

013018   Deepak Kumar;Verma V K;Mishra L K (Physics Dep, Magadh Univ, Bodh-Gaya, Bihar) : Evaluation of temperature variation resistivity of alkali metal doped fluoride K₃C₆₀. J pure appl ind Phys 2013, 3(2), 142-7.

Using the theoretical formulism developed by L. Pintschovius. (1996), and have presented a method of evaluation of temperature dependent resistivity ρ_e-ph (electron-Phonon), ρ_er (Inter molecular Phonon), ρ_ra (Intra molecular Phonon), total resistivity ρ_(T)and ρ_diff (Difference between theoretical-experimental) for K₃C₆₀o fluoride. Our theoretical results are in good agreement with experimental data and also with other theoretical workers.

4 tables, 25 ref

013017   Dass T (NO, Indian Statistical Institute, 7, S.J.S. Sansanwal Marg, New Delhi 110 016, Email: tulsi@iitk.ac.in) : Stepwise planned approach to the solution of Hilbert's sixth problem. III: measurements and Von Neumann projection/collapse rule. Pramana J Phys 2011, 77(6), 1031-51.

Supmech, the universal mechanics developed in the previous two papers (Dass, arXiv: 0909.4606[math-ph]; 1002:206 l[math-ph]), accommodates both quantum and classical mechanics as subdisciplines (a brief outline is included for completeness); this feature facilitates, in a supmech-based treatment of quantum measurements, an unambiguous treatment of the apparatus as a quantum system approximated well by a classical one. Taking explicitly into consideration the fact that observations on the apparatus are made when it has 'settled down after the measurement interaction' and are restricted to macroscopically distinguishable pointer readings, the unwanted superpositions of (system + apparatus) states are shown to be suppressed; this provides a genuinely physics-based justification for the (traditionally postulated) Von Neumann projection/collapse rule. The decoher-ence mechanism brought into play by the stated observational constraints is free from the objections against the traditional decoherence program.

19 ref

013016   Das A;Yadav S K;Kaw P;Sengupta S (NO, Institute of Plasma Research, Bhat, Gandhinagar-382 428, Email: amita@ipr.res.in) : Collisionless stopping of electron current in an inhomogeneous electron magnetohydrodynamics plasma. Pramana J Phys 2011, 77(5), 949-57.

Brief review of a recent work on a novel collisionless scheme for stopping electron current pulse in plasma is presented. This scheme relies on the inhomogeneity of the plasma medium. This mechanism can be used for heating an overdense regime of plasma where lasers cannot penetrate. The method can ensure efficient localized heating at a desired location. The suitability of the scheme to the frontline fast ignition laser fusion experiment has been illustrated.

3 illus, 9 ref

013015   Dabkara N K;Firozia D S;Ahirwar G (Physics Dep, Government Girl's College, Neemuch, M.P.) : Maximum limit of rotational energy transfer on O₂ collision with he and hard ellipsoid potential model. J pure appl ind Phys 2013, 3(2), 72-8.

Importance of power-gap law which is treat as well known parameter |AE|* given by two parameters and the classical limit of the maximum rotational energy transfer, (ΔE)_max, has been reviewed for a two dimensional hard ellipsoid potential model over a wide range of energies of the system. It has been found that (ΔE)_max, predicted by the hard ellipsoid potential is comparable to a well-known parameter |AE|*. The numerical equivalence of (ΔE)_max and |ΔE|* has been verified for different collision energy of the system. Such equivalence suggests that the value of (ΔE)_max can be used as one parameter |ΔE| of the power-gap law.

2 illus, 2 tables, 21 ref

013014   Chugh R;Sood A D (Centre for Advanced Study in Physics, Physics Dep, Panjab Univ, Chandigarh-160 014, Email: amandsood@gmail.com) : Geometry of vanishing flow: a new probe to determine the in-medium nucleon-nucleon cross-section. Pramana J Phys 2011, 77(2), 289-95.

Studied the transverse flow throughout the mass range from ²⁰Ne + ²⁰Ne to ¹³¹Xe+¹³¹Xe as a function of the impact parameter. We found that at smaller impact parameters the flow is negative while going through the impact parameter, transverse flow vanishes at a particular colliding geometry named GVF. They have found that the mass dependence of GVF is insensitive to the equation of state and momentum-dependent interactions whereas it is quite sensitive to the cross-section. So it can act as a useful tool to pin down the nucleon-nucleon cross-section.

3 illus, 24 ref

013013   Choudhury D;Saha P (Physics and Astrophysics Dep, Delhi Univ, Delhi-110 007) : Probing top anomalous couplings at the Tevatron and the large hadron collider. Pramana J Phys 2011, 77(6), 1079-93.

Chromomagnetic and chromoelectric dipole interactions of the top quark are studied in a model-independent framework. Limits are set on the scale of new physics that might lead to such contributions using latest Tevatron measurements of the tt cross-section. It is demonstrated that the invariant mass distribution is a sensitive probe. Prospects at the LHC are examined. It is shown that, for unitarized amplitudes, an increase in the LHC energy is of little importance, while the accumulation of luminosity plays a crucial role.

5 illus, 1 table, 34 ref

013012   Choudhuri A R (Physics Dep, Indian Institute of Science, Bangalore-560 012, Email: arnab@physics.iisc.ernet.in) : Origin of the solar magnetic cycle. Pramana J Phys 2011, 77(1), 77-96.

After summarizing the relevant observational data, discuss how a study of flux tube dynamics in the solar convection zone helps us to understand the formation of sunspots. Then introduce the flux transport dynamo model and assess its success in modelling both the solar cycle and its departures from strictly periodic behaviour.

14 illus, 66 ref

013011   Chatterjee Singh N (National Brain Research Centre, , NH-8, Nainwal Mode, Manesar-122 050, Email: nandini@nbrc.ac.in) : Measuring the 'complexity' of sound. Pramana J Phys 2011, 77(5), 811-16.

Sounds in the natural environment form an important class of biologically relevant non-stationary signals. And propose a dynamic spectral measure to characterize the spectral dynamics of such non-stationary sound signals and classify them based on rate of change of spectral dynamics. Author categorize sounds with slowly varying spectral dynamics as simple and those with rapidly changing spectral dynamics as complex. Also propose rate of spectral dynamics as a possible scheme to categorize sounds in the environment.

2 illus, 1 table, 5 ref

013010   Bhandakkar V D;Asole A W (NO, Anand Niketan College, Warora, M.S.) : Excess thermodynamic parameters of binary liquid mixtures at 303K. J pure appl ind Phys 2013, 3(2), 80-6.

Experimental density (ρ), viscosity (η)) and velocity (U) have been measured for binary liquid mixtures of Methylmethacrylate with methanol, cyclohexane and 1,4-dioxane at the temperature 303K. These data were used to determine the excess adiabatic compressibility(β^E_a), excess free length(L^E_f), excess free volume(V^E_f), excess internal pressure(π^E_i), excess relaxation" time(τ^E), excess acoustic impedance(Z_a^E) and excess Gibb's(ΔG^E). From these excess parameters, the nature and the strength of molecular interactions in these binary systems are discussed.

7 illus, 4 tables, 19 ref

013009   Beesham A (Mathematical Sciences Dep, Zululand Univ, Private Bag X1001, Kwa-Dlangezwa 3886, South Africa, Email: abeesham@pan.uzulu.ac.za) : Gravitational collapse with decaying vacuum energy. Pramana J Phys 2011, 77(3), 429-32.

The effect of dark energy on the end state of spherical radiation collapse is considered within the context of the cosmic censorship hypothesis. It is found that it is possible to have both black holes as well as naked singularities.

1 table, 8 ref

013008   Bedare G R;Bhandakkar V D;Suryavanshi B M (Physics Dep, N.S. Science & Arts College, Bhadrawati Dist.- Chandrapur, Maharashtra) : Acoustical and thermodynamic properties of binary mixtures at 303 K. J pure appl ind Phys 2013, 3(1), 63-7.

Using ultrasonic technique, the molecular interaction studies in the binary liquid mixtures of two aliphatic alcohols ethanol and methanol with 1, 4-dioxane has been carried out at 303K. The ultrasonic velocity, density and viscosity at 303 K have been measured. From the experimental data, various acoustical parameters such as adiabatic compressibility (β_a), intermolecular free length (L_f), free volume (V_f) and internal pressure (JI_i) were calculated. It has been observed that, weak dispersive type intermolecular interactions are confirmed in the systems investigated. The results are interpreted in terms of molecular interaction between the components of the mixtures.

6 illus, 2 tables, 13 ref

013007   Balakrishnan R;Satija I I (NO, The Institute of Mathematical Sciences, Chennai-600 113, Email: radha@imsc.res.in) : Solitons inm Bose-Einstein condensates. Pramana J Phys 2011, 77(5), 929-47.

Gross-Pitaevskii equation (GPE) describing the evolution of the Bose-Einstein con-densate (BEC) order parameter for weakly interacting bosons supports dark solitons for repulsive interactions and bright solitons for attractive interactions. After a brief introduction to BEC and a general review of GPE solitons, we present our results on solitons that arise in the BEC of hard-core bosons, which is a system with strongly repulsive interactions. For a given background density, this system is found to support both a dark soliton and an antidark soliton (i.e., a bright soliton on a pedestal) for the density profile. When the background has more (less) holes than particles, the dark (antidark) soliton solution dies down as its velocity approaches the sound velocity of the system, while the antidark (dark) soliton persists all the way up to the sound velocity. This persistence is in contrast to the behaviour of the GPE dark soliton, which dies down at the Bogoliubov sound velocity. The energy-momentum dispersion relation for the solitons is shown to be similar to the exact quantum low-lying excitation spectrum found by Lieb for bosons with a delta-function interaction.

3 illus, 22 ref

013006   Ambika G;Amritkar R E (Physics Dep, Indian Institute of Science Education and Research, Pune-411 021, Email: g.ambika@iiserpune.ac.in) : Delay or anticipatory synchronization in one-way coupled systems using variable delay with reset. Pramana J Phys 2011, 77(5), 891-904.

Presents a mechanism for the synchronization of one-way coupled nonlinear systems in which the coupling uses a variable delay, that is reset at finite intervals. Here the delay varies in the same way as the system in time and so the coupling function remains constant for the reset interval at the end of which it is reset to the value at that time. This leads to a novel and discrete error dynamics and the resulting general stability analysis is applicable to chaotic or hyperchaotic systems. Authors apply this method to standard chaotic systems and hyperchaotic time delay systems. The results of the detailed numerical analysis agree with the results from stability analysis in both cases. This method has the advantage that it is cost-effective since information from the driving system is needed only at intervals of reset. Further, in the context of time delay systems, optimization among the different time-scales depending upon the application is possible due to the flexibility among the four different time-scales in our method, viz. delay in the driving system, anticipation in the response system, system delay time and reset time. And suggest a bi-channel scheme for implementing this method in communication field with enhanced security.

9 illus, 36 ref

013005   Akbari-Moghanjoughi M;Ahmaszadeh-Khosroshahi N (Faculty of Science, Physics Dep, Azarbaijan Tarbiat Moallem Univ, 51745-406, Tabriz, Iran, Email: m_akbari@azaruniv.edu) : Propagation and oblique collision of electron-acoustic solitons in two-electron-populated quantum plasmas. Pramana J Phys 2011, 77(2), 369-82.

Oblique interaction of small- but finite-amplitude KdV-type electron-acoustic solitary excitations is examined in an unmagnetized two-electron-populated degenerate quantum electron-ion plasma in the framework of quantum hydrodynamics model using the extended Poincare-Lighthill-Kuo (PLK) perturbation method. Critical plasma parameter is found to distinguish the types of solitons and their interaction phase-shifts. It is shown that, depending on the critical quantum diffraction parameter H_cr,, both compressive and rarefactive solitary excitations may exist in this plasma and their collision phase-shifts can be either positive or negative for the whole range of collision angles 0 <60> θ <60>π.

1 illus, 47 ref

013004   Ahmed B;Raghuvanshi S K;Siddhartha;Srivastava A K;Krishna J B M;Wahab M A (Physics Dep, Jamia Millia Islamia a Central Univ, New Delhi-110 025) : Optical and structural study of aromatic polymers irradiated by gamma radiation. Indian J pure appl Phys 2012, 50(12), 892-8.

Aromatic polymers have proven their potential in the field of electronics, space and nuclear technology. Aromatic polymers have been found to have very good electrical properties, mechanical strength and high melting points (260°C to 350°C) due, to the presence of aromatic ring in the polymer back bone. In the present paper, the optical and structural properties of virgin and high dose (500-2000 kGy) γ-irradiated samples of aromatic polymers such as kapton and PES have been studied. These polymer samples were analyzed by using UV-Visible spectrophotometer in the wavelength range 190-900 nm. From the optical spectrum, we found that the absorption and optical band gaps (E_g) of virgin and irradiated kapton and PES polymer samples decrease with increasing dose. The existence of the maximum absorption, their shifting and broadening due to gamma irradiation have been investigated. The structural studies have been done by using X-ray diffractometry (XRD) analysis. The diffraction pattern of kapton and PES polymers indicates recrystallization and increase in the crystallinity with increasing dose.

8 illus, 2 tables, 26 ref

013003   Ahmadian F;Zare R (Physics Dep, Shahreza Branch, Islmaic Azad Univ, Shahreza, Iran) : Electronic structure and band alignments of ZnTe/CrTe(0 0 1), CdSe/CrTe(0 0 1) and CdTe/CrTe(0 0 1) interfaces. Pramana J Phys 2011, 77(2), 383-94.

All-electron full potential calculations based on spin density functional theory were performed to study cubic zincblende (ZB) and hexagonal NiAs structures of bulk CrTe and ZnTe/ CrTe(00 1), CdTe/CrTe(00 1) and CdSe/CrTe(0 0 1) interfaces. The lattice mismatch effect in ZB CrTe and magnetic properties of CrTe in the ideal ZB CrTe structure were investigated. The band alignment properties of the ZnTe/CrTe(00 1), CdTe/CrTe(00 1) and CdSe/CrTe(00 1) interfaces were computed and a rather large minority valence band offset of about 1.09 eV was observed in ZnTe/CrTe(00 1) heterojunction. Also in the CdTe/CrTe(00 1) and CdSe/CrTe(00 1) interfaces, the conduction band minimum of minority spin in CrTe was above the conduction band minimum of CdTe and CdSe and so the majority spin electrons could be directly injected to both semiconductors, indicating the possibility of highly efficient spin injection into the CdSe and CdTe semiconductors.

6 illus, 2 tables, 31 ref

011917   Yadav R P;Rohitashw Kumar;Kumar S;Yadav M (Physics Dep, Govt. P.G. College, Bisalpur, Pilibhit-262 201, Email: rpyadav93pphysics@yahoo.com) : The interaction of overtaking disturbances with strong spherical shock waves in sea water. Ultra Scient phys Sci-Sect B 2011, 23(2), 412-22.

The propagation of strong spherical shock in sea water is investigated by CCW method.Effect of overtaking disturbances is included using Yadav techniques Analytical expression for shock velocity and shock strength are obtained for two cases viz. (i) when shock moves freely and (ii) when it moves under the influence of overtaking disturbances. Assuming uniform density distribution, the pressure and particle velocity just behind the shock are obtained for both the cases. Their variation with propagation distance and specific heat index of water are computed and discussed with the help of tables. The results obtained are compared with those obtained by other method.

8 tables, 15 ref

011916   Yadav M;Baluni C;Mehra V P (Physics Dep, Govt. P.G. College, Kotdwar, Pauri Garhwal, Uttarakhand-246 149) : Effect of overtaking disturbances on strong hydromagnetic cylindrical shock waves in a rotating gas. Ultra Scient phys Sci-Sect B 2011, 23(1), 91-102.

In the present paper effect of overtaking disturbances on the freely propagation of strong hydromagnetic cylindrical shock waves through rotating gas is studied by a technique developed by Yadav. Assuming an initial density at the axis of symmetry, the analytical relation for flow variables modified by overtaking disturbances are obtained. The variation of flow variable with (i) Propagation distances (ii) Angular velocity Ω and (iii) Magnetic field β are obtained. The results obtained here are also compared with those for a freely propagating shock.

3 illus, 17 ref

011915   Verma K R;Sharma K;Saxena S (Basic Sciences Dep, S.R.M.S. College of Engg. & Tech., Bareilly) : Positron impact excitation of atomic helium: angular correlation parameter (γ). Ultra Scient phys Sci-Sect B 2011, 23(3), 673-6.

In this paper, we focus our attention and deal with positron impact excitation of n = 2 state of Helium from its ground state with the point of view of angular correlation parameter (γ) at 50eV. To calculate this parameter, distorted wave approximation theory with different choices of distorted potential has been used. The result for 1¹ S-2¹ S transition is compared with available theoretical and experimental data. We found that these obtained results are quite sensitive to choice of distortion potential used.

1 illus, 8 ref

011914   Venkat Rao P;Adeel Ahmad;Bellubbi B S (Biophysics Unit, Physics Dep, Nizam College, Osmania Univ, Hyderabad-500 001) : X-ray diffractrometric studies on human nail. Ultra Scient phys Sci-Sect B 2011, 23(2), 293-8.

This paper is concerned with the identification of inorganic constituent of human nail and crystallanity of human nail mineral and protein. The presence of inorganic material in human finger nail, whether it is of male or female, is scanty. The crystallanity, size distribution and preferential orientation of crystallite are ruled out.

2 illus, 7 ref

011913   Varghese H T;Yohannan Panicker C;Sheena Marry Y;Abdul Salim M (Physics Dep, Fatima Mata National College, Kollam, Kerala, Email: cyphyp@rediffmail.com) : Vibrational spectroscopic and computational study of benzoxazole. Ultra Scient phys Sci-Sect B 2011, 23(3), 724-8.

In the present work, the vibrational wavenumbers of the title compound are calculated theoretically at different levels of theory and compared with the experimental results.

1 table, 21 ref