020012   Chaudhary G K;Ramakumar R (Physics and Astrophysics Dep, Delhi Univ, Delhi-110 007, Email: gkchaudhary@physics.du.ac.in) : Effect of next-to-nearest-neighbour hopping on bose-einstein condensation in cubic lattices. Pramana J Phys 2010, 74(1), 11-18.

Results of the calculations on the effects of next-to-nearest-neighbour boson hopping (t') energy on Bose-Einstein condensation in cubic lattices. We consider both non-interacting and repulsively interacting bosons moving in the lowest Bloch band. The interacting bosons are studied using Bogoliubov method. We find that the Bose condensation temperature is enhanced by increasing t' for bosons in a simple cubic (sc) lattice and decreases for bosons in body-centred cubic (bcc) and face-centred cubic (fee) lattices. We also find that interaction-induced depletion of the condensate is reduced for bosons in an sc lattice while it is enhanced for bosons in bcc and fee lattices.

6 illus, 23 ref

020011   Chakrabarti B (Physics Dep, Lady Brabourne College, 1/2 Suhrawardy Avenue, Kolkata-700 017, Email: chakb@rediffmail.com) : Use of supersymmetric isospectral formalism to realistic quantum many-body problems. Pramana J Phys 2009, 73(2), 405-16.

Proposes a novel mathematical approach for the calculation of resonances in weakly bound systems. For any potential, families of strictly isospectral potentials (with very different shape) having desirable and adjustable features can be generated. For systems having no bound ground state, an isospectral potential with a bound state in the continuum is possible. The quasi-bound state in the original shallow potential will be effectively trapped in the deep well of the isospectral family, facilitating more accurate calculation of resonance energy. Application to ⁶He, ⁶Li and ⁶Be yield excellent results. Another application is the calculation of Efimov states in weakly bound three-body system. We present the result of ⁴He trimer, where the first excited state is claimed to be an Efimov state.

3 illus, 22 ref

020010   Calik A E;Deniz C;Gerceklioglu M (Physics Dep, Faculty of Science, Ege Univ, 35100 Bornova, Izmir, Turkey, Email: gerceklioglu@ege.edu.tr) : Neutron-proton pairing and the moments of inertia of the rare earth even-even nuclei. Pramana J Phys 2009, 73(5), 847-57.

In this study, the possible effect of the neutron-proton pairing interaction in the heavy nuclei has been investigated in the framework of the BCS model by making a simple approximation. This effect has been searched realistically by calculating the moments of inertia of deformed even-even nuclei. Calculations show that the moments of inertia of rare earth nuclei changed dramatically and approached the experimental values.

4 illus, 1 table, 44 ref

020009   Boya L J;Rivera C;Sudarshan E C G (Departanmento de Fiscia Teorica, Universidad de Zangoza E-50009 Zaragonza, Spain, Email: luisjo@unizar.es) : Note on the natural system of units. Pramana J Phys 2009, 73(6), 961-8.

Proposed to substitute Newton's constant GN for another constant G₂, as if the gravitational force would fall off with the 1/r law, instead of the 1/r²; so we describe a system of natural units with G2, c and H. We adjust the value of G₂ so that the fundamental length L = L_P1 is still the Planck's length and so GN = L x G₂. We argue for this system as (1) it would express longitude, time and mass without square roots; (2) G₂ is in principle disentangled from gravitation, as in (2 + 1) dimensions there is no field outside the sources. So G₂ would be truly universal; (3) modern physics is not necessarily tied up to (3 + l)-dim. scenarios and (4) extended objects with p = 2 (membranes) play an important role both in M-theory and in F-theory, which distinguishes three (2,1) dimensions. As an alternative we consider also the clash between gravitation and quantum theory; the suggestion is that non-commutative geometry [x_i, x_j] = A²θ_ij would cure some infinities and improve black hole evaporation. Then the new length A shall determine, among other things, the gravitational constant G_N.

17 ref

020008   Bisht P S;Negi O P (Physics Dep, Kumaun Univ, S.S.J. Campus, Almora-263 601, Email: ps_bisht123@rediffmail.com) : Octonion wave equation and tachyon electrodynamics. Pramana J Phys 2009, 73(3), 605-13.

The octonion wave equation is discussed to formulate the localization spaces for subluminal and superluminal particles. Accordingly, tachyon electrodynamics is established to obtain a consistent and manifestly covariant equation for superluminal electromagnetic fields. It is shown that the true localization space for bradyons (subluminal particles) is -R⁴- (three space and one time dimensions) space while that for the description of tachyons is T⁴- (three time and one space dimensions) space.

9 ref

020007   Bila H (NO, , Ustav Jaderne Fyziky AV CR, 25068 Rez, Prague, Czech Republic, Email: hynek.bila@ujf.cas.cz) : Spectra of PT-symmetric Hamiltonians on tobogganic contours. Pramana J Phys 2009, 73(2), 307-14.

A non-standard generalization of the Bender potentials x²(ixε) is suggested. The spectra are obtained numerically and some of their particular properties are discussed.

7 illus, 4 ref

020006   Bhatia S N;Mohapatra N;Nirmala R;Malik S K (Physics Dep, Indian Institute of Technology Bombay, Mumbai-400 076, Email: snbhatia@phy.iitb.ac.in) : Effect of spin dilution on magnetism of the linear chain system β-Cu_2-xZn_xV₂O₇. Pramana J Phys 2010, 74(5), 833-43.

Authors have measured the magnetic susceptibility (x) and heat capacity (C_p) of β-Cu_2-xZn_xV₂O₇ (x = 0, 0.05, 0.1, 0.15, 0.2, 0.3, 2) in the temperature range 2-300 K. A one-dimensional alternating exchange Heisenberg antiferromagnetism (HAF) is observed in all compositions with chains of infinite length. The intra-chain exchange remains uniform and decreases marginally with dilution of the magnetic state. A cooperative ordering is seen in the magnetic chains for all Zn concentrations (x ≤ 0.3). The temperature of occurrence of this transition decreases with increasing Zn concentration. Though the conventional spin-wave theory has been used here to describe the properties of the ordered phase, the presence of some contributions like the lattice heat capacity in C_p and the Curie-Weiss term in susceptibility introduces some uncertainties in the estimation of the proportions contributed by the spin system. Therefore, the nature of the ordered phase could not be ascertained unambiguously.

5 illus, 1 table, 29 ref

020005   Bhadra J;Sarkar D (Physics Dep, Gauhati Univ, Guwahati-781 014, Email: sarkardeepali@gmail.com) : Size variation of polyaniline nanoparticles dispersed in polyvinyl alohol matrix. Bull Mater Sci 2010, 33(5), 519-23.

Reports the preparation of polyaniline (PANI) nanoparticles dispersed in polyvinyl alcohol (PVA) matrix. From SEM picture it is seen that the particle sizes vary from 100-20 nm. Also with increase in PVA content the stability of dispersion is found to increase. Apart from SEM, spin cast films of PANI in PVA are also characterized through XRD and FTIR. XRD shows increase in crystallinity with PVA content and FTIR gives evidence of crosslinking between PANI and PVA molecules. In plane electrical conductivity (in the range of 10² ScnT^-1) and the exponent of nonlinear I-V are found to decrease with increase of PVA content. There is a good correlation between SEM, XRD, FTIR and electrical properties.

3 illus, 31 ref

020004   Bender C M;Feinberg J A;Hook D W;Weir D J (Physics Dep, Washington Univ, St. Louis, Mo 63130, USA, Email: cmb@wustl.edu) : Chaotic system in complex phase space. Pramana J Phys 2009, 73(3), 453-70.

This paper examines numerically the complex classical trajectories of the kicked rotor and the double pendulum. Both of these systems exhibit a transition to chaos, and this feature is studied in complex phase space. Additionally, it is shown that the short-time and long-time behaviours of these two PT-symmetric dynamical models in complex phase space exhibit strong qualitative similarities.

16 illus, 34 ref

020003   Bender C M;Cooper F;Khare A;Mihaila B;Saxena A (Physics Dep, Washington Univ, St. Louis, MO 63130, USA, Email: khare@iopb.res.in) : Compactons in PT-symmetric generalized Korteweg-de Vries equations. Pramana J Phys 2009, 73(2), 375-85.

This paper considers the PT-symmetric extensions of the equations examined by Cooper, Shepard and Sodano. From the scaling properties of the 'PT-symmetric equations a general theorem relating the energy, momentum and velocity of any solitary-wave solution of the generalized Kd V equation is derived. We also discuss the stability of the compacton solution as a function of the parameters affecting the nonlinearities.

1 illus, 15 ref

020002   Bayri A;Bakir H G;Sulu M;Karakaplan M (Physics Dep, Arts and Science Faculty, Adiyaman Univ, Tr-0204 Adiyaman, Turkey) : Attempt to understand the observed plateau of magnetization in tetranuclear iron(II) complexes of thiacalixarene macrocycles. Pramana J Phys 2010, 74(3), 391-97.

The next-nearest-neighbour (NNN) effect in tetranuclear iron(II) complexes of thiacalixarene macrocycles using the isotropic Heisenberg model has been investigated in order to understand its effects on the observed plateau of magnetization. Although NNN effect is generally very weak in these kinds of systems, it was calculated that its response is quite significant to the external perturbations in certain temperature regions. Using the isotropic Heisenberg exchange Hamiltonian, zero-field energy spectra have been calculated for this particular tetranuclear system. The average magnetic moments with and without next-nearest-neighbour interactions were also calculated. In order to verify the calculations, the results were compared with experimental data taken from the literature, whence, it is suggested that observed magnetic behaviour can be improved by taking into account the NNN effect.

2 illus, 40 ref

020001   Baskaran G (The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai-600 113, Email: baskaran@imsc.res.in) : Five-fold way to new high Tc superconductors. Pramana J Phys 2009, 73(1), 61-113.

Discovery of high T_c superconductivity in La_2-xBa_zCuO₄ by Bednorz and Muller in 1986 was a breakthrough in the 75-year long search for new superconductors. Since then new high T_c superconductors, not involving copper, have also been discovered. Superconductivity in cuprates also inspired resonating valence bond (RVB) mechanism of superconductivity. In turn, RVB theory provided a new hope for finding new superconductors through a novel electronic mechanism. This article first reviews an electron correlation-based RVB mechanism and our own application of these ideas to some new noncuprate superconducting families. In the process we abstract, using available phenomenology and RVB theory, that there are five directions to search for new high T_c superconductors. We call them five-fold way. As the paths are reasonably exclusive and well-defined, they provide more guided opportunities, than before, for discovering new superconductors. The five-fold ways are (i) copper route, (ii) pressure route, (iii) diamond route, (iv) graphene route and (v) double RVB route. Copper route is the doped spin-1/2 Mott insulator route. In this route one synthesizes new spin-1/2 Mott insulators and dopes them chemically. In pressure route, doping is not external, but internal, a (chemical or external) pressure-induced self-doping suggested by organic ET-salts. In the diamond route we are inspired by superconductivity in boron-doped diamond and our theory. Here one creates impurity band Mott insulators in a band insulator template that enables superconductivity. Graphene route follows from our recent suggestion of superconductivity in doped graphene, a two-dimensional broadband metal with moderate electron correlations, compared to cuprates, Double RVB route follows from our recent theory of doped spin-1 Mott insulator for superconductivity in iron pnictide family.

19 illus, 103 ref

020000   Bari R H;Patil L A (P.G. Dep of Physics, Pratap College, Amalner-425 401, Email: plalchand_phy_aml@yahoo.co.in) : Preparation and characterization of nanostructured copper bismuth diselenide thin films from a chemical route. Bull Mater Sci 2010, 33(6), 663-70.

Thin films of copper bismuth diselenide were prepared by chemical bath deposition technique onto glass substrate below 60°C. The deposition parameters such as time, temperature of deposition and pH of the solution, were optimized. The set of films having different elemental compositions was prepared by varying Cu/Bi ratio from 0-13-1-74. Studies on structure, composition, morphology, optical absorption and electrical conductivity of the films were carried out and discussed. Characterization includes X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray analysis (EDAX), absorption spectroscopy, and electrical conductivity. The results are discussed and interpreted.

11 illus, 6 tables, 11 ref

019999   Banyal R K;Raghavendra Prasad B (NO, Indian Institute of Astrophysics, Bangalore-560 034, Email: banyal@iiap.res.in) : Nonlinear response studies and corrections for a liquid crystal spatial light modulator. Pramana J Phys 2010, 74(6), 961-71.

The nonlinear response of light transmission characteristics of a liquid crystal (LC) spatial light modulator (SLM) is studied. The results show that the device exhibits a wide range of variations with different control parameters and input settings. Experiments were performed to obtain intensity modulation that is best described by either power-law or sigmoidal functions. Based on the inverse transformation, an appropriate pre-processing scheme for electrically addressed input gray-scale images, particularly important in several optical processing and imaging applications, is suggested. Further, the necessity to compensate the SLM image nonlinearities in a volume holographic data storage and retrieval system is demonstrated.

7 illus, 1 table, 27 ref

019998   Bansal S;Mazumdar M;Singh J B (Physics Dep, Panjab Univ, Chandigarh-160 014) : Search for invisibly decaying higgs boson at large hadron collider. Pramana J Phys 2010, 74(2), 231-46.

In several scenarios of Beyond Standard Model physics, the invisible decay mode of the Higgs boson is an interesting possibility. The search strategy for an invisible Higgs boson at the Large Hadron Collider (LHC), using weak boson fusion process, has been studied in detail, by taking into account all possible backgrounds. Realistic simulations have been used in the context of CMS experiment to devise a set of event selection criteria which eventually enhances the signal contribution compared to the background processes in characteristic distributions. In cut-based analysis, multi-jet background is found to overwhelm the signal in the finally selected sample. With an integrated luminosity of 10 fb^-1, an upper limit of 36% on the branching ratio can be obtained for Higgs boson with a mass of 120 GeV/c² for LHC energy of 14 TeV. Since the analysis essentially depends on the background estimation, detailed studies have been done to determine the background rates from real data.

8 illus, 1 table, 22 ref

019997   Banerjee N;Das S;Ganguly K (Physics Dep, Relativity and Cosmology Research Centre, Jadavpur Univ, Kolkata-700 032, Email: narayan@iiserkol.ac.in) : Chameleon field and the late time acceleration of the universe. Pramana J Phys 2010, 74(3), 481-89.

In the present work, it is shown that a chameleon scalar field having a non-minimal coupling with dark matter can give rise to a smooth transition from a decelerated to an accelerated phase of expansion for the Universe. It is surprising to note that the coupling with the chameleon scalar field hardly affects the evolution of the dark matter sector, which still redshifts as a^-3.

3 illus, 20 ref

019996   Balram A C;Dhar D (Physics Dep, Indian Institute of Science Education and Research, Sai Trinity Building, Garware Circle, Sutarwadi, Pashan, Pune-411 021, Email: cb.ajit@iiserpune.ac.in) : Scaling relation for determining the critical threshold for continuum percolation of overlapping discs of two sizes. Pramana J Phys 2010, 74(1), 109-14.

Studies continuum percolation of overlapping circular discs of two sizes. We propose a phenomenological scaling equation for the increase in the effective size of the larger discs due to the presence of the smaller discs. The critical percolation threshold as a function of the ratio of sizes of discs, for different values of the relative areal densities of two discs, can be described in terms of a scaling function of only one variable. The recent accurate Monte Carlo estimates of critical threshold by Quintanilla and Ziff [Phys. Rev. E76, 051115 (2007)] are in very good agreement with the proposed scaling relation.

3 illus, 15 ref

019995   Ayesh A S;Abdel-Rahem R (Physics Dep, College of Science, King Faisal Univ, Al Hafouf 31982, Kingdom of Saudi Arabia) : Effect of Ba(Ti_(o.9)Sn_0.1)O₃ ceramic doping on optical, thermal and dielectric properties of polycarbonate host. Bull Mater Sci 2010, 33(5), 589-95.

Ba(Ti_(0.9)Sn_0.1i)O₃ (BTS) ceramic was prepared by a conventional ceramic processing. BTS-polycarbonate (PC) composites were prepared at different BTS concentrations by weight in order to study their optical and dielectric properties. The absorption coefficient (a) was determined in the wavelength range from 250-600 nm at room temperature for all BTS-PC composites. The optical gap (E_opt) was also determined for BTS-PC composites. The variation of the absorption coefficient (α) and optical gap (E_opt) with BTS content are reported. It was found that BTS ceramic highly enhances the UV absorption of PC host at 300 nm. The optical gap decreases up to the value of 3-93 eV as BTS content increases up to 35 wt% and this was attributed to the formation of localized states in the forbidden gap. The relative dielectric permittivity, dielectric loss and loss tangent were measured at temperature range from room temperature up to 150°C and at frequency values 1 kHz, 10 kHz and 50 kHz. Addition of BTS to PC host, however, will increase relative dielectric permittivity, dielectric loss and loss tangent. Besides, increasing of temperature will also increase relative dielectric permittivity, dielectric loss and loss tangent especially above the glass transition temperature of PC host and this behaviour was attributed to the segmental motion of polymer chains. On the other hand, this study shows that there is a good agreement between SEM, DSC and dielectric results and also between optical gap and a.c. conductivity results. Moreover, SEM and DSC results reveal that addition of BTS ceramic particles to PC host will reduce the physical bond between polymer chains or may be will increase the free volume in the polymer host and consequently will enhance the segmental motion of polymer chains and this behaviour is independent of ceramic phase.

11 illus, 1 table, 23 ref

019994   Asnani H;Mahajan R;Pathak P;Singh V A (Electrical Engineering Dep, Indian Institute of Technology Bombay, Mumbai-400 076, Email: ksingh@mailhost.tifr.res.in) : Effective mass theory of a two-dimensional quantum dot in the presence of magnetic field. Pramana J Phys 2009, 73(3), 573-80.

The effective mass of electrons in low-dimensional semiconductors is position-dependent. The standard kinetic energy operator of quantum mechanics for this position-dependent mass is non-Hermitian and needs to be modified. This is achieved by imposing the BenDaniel-Duke (BDD) boundary condition. We have investigated the role of this boundary condition for semiconductor quantum dots (QDs) in one, two and three dimensions. In these systems the effective mass mi inside the dot of size R is different from the mass m_o outside. Hence a crucial factor in determining the electronic spectrum is the mass discontinuity factor β = β_i/m_o. We have proposed a novel quantum scale, σ, which is a dimensionless parameter proportional to β²R²V_o, where V_o represents the barrier height. We show both by numerical calculations and asymptotic analysis that the ground state energy and the surface charge density, (ρ(R)), can be large and dependent on σ. We also show that the dependence of the ground state energy on the size of the dot is infraquadratic. We also study the system in the presence of magnetic field B. The BDD condition introduces a magnetic length-dependent term (h/eB) into σ and hence the ground state energy. Demonstrates that the significance of BDD condition is pronounced at large R and large magnetic fields. In many cases the results using the BDD condition is significantly different from the non-Hermitian treatment of the problem.

3 illus, 1 table, 8 ref

019993   Aquino F D (Maranhao State Univ, Physics Dep, S.Luis/MA, Brazil) : Physical foundations of quantum psychology. Bull pure appl Sci-Sect D 2010, 29(2), 105-29.

The existence of imaginary mass associated to the neutrino is already well-known. Although its imaginary mass is not physically observable, its square is. This amount is found experimentally to be negative. Recently, it was shown that quanta of imaginary mass exist associated to the electron and the photon too. These imaginary masses have unusual properties that violate the Parity Conservation Principle. The non-conservation of the parity is also found in the weak interactions, and possibly can be explained by means of the existence of the imaginary masses. Also protons and neutrons would have imaginary masses associated to them and, in this way, atoms and molecules would also have imaginary masses directly proportional to their atomic and molecular masses. The Parity Conservation Principle holds that the material particles are not able to distinguish their right from their left. The non-conservation of the parity would necessarily imply capability of "choice". Thus, as the particles with imaginary mass don't conserve the parity, they would have the elementary capability of "choosing between their right or left". Where there is "choice" isn't there also psychism, by definition? This fundamental discovery shows that, in some way, the consciousnesses are related to the imaginary masses. This fact, make it possible to redefine Psychology on a Quantum Physics basis.

14 ref

019992   Anita H M (Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400 005, Email: anita@tifr.res.in) : Solar interior. Curr Sci 2009, 97(6), 911-22.

The Sun being the nearest star, provides us a unique opportunity to study stellar processes in sufficient detail to test theories of stellar structure and evolution. Although the solar interior is not directly accessible to observations, development of helioseismology during the last three decades has enabled us to study the structure and dynamics of solar interior with unprecedented accuracy. Some of these developments are described in this article.

6 illus, 86 ref

019991   Aneesh P M;Jayaraj M K (Physics Dep, Cochin Univ of Science and Technology, Kochi-682 022, Email: mkj@cusat.ac.in) : Red luminescence from hydrothermally synthesized Eu-doped ZnO nanoparticles under visible excitation. Bull Mater Sci 2010, 33(3), 227-31.

Eu-doped ZnO nanoparticles were synthesized by hydrothermal method. The Eu-dopant concentration has been varied by varying the amount of Eu-dopant concentration. These nanoparticles were structurally characterized by X-ray diffraction, transmission electron microscopy and selected area electron diffraction and it confirms the formation of nanoparticles having standard wurtzite structure. Photo-luminescence studies show that these nanoparticles exhibit a sharp red luminescence due to the intra-4/transitions of Eu³⁺ ions at an excitation of 397 nm and 466 nm. Luminescence quenching is observed in the nanoparticles as the Eu-dopant concentration increases. Incorporation of Eu in the nanoparticles was confirmed by the energy dispersive X-ray studies.

8 illus, 27 ref

019990   Ahn C K (Faculty of the Division of Electronics and Control Engineering, Wonkwang Univ, 344-2 Shinyoung-dong, Iksan 570-749, Korea, Email: hironaka@wonkwang.ac.kr) : Robust chaos synchronization using input-to-state stable control. Pramana J Phys 2010, 74(5), 705-18.

In this paper, propose a new input-to-state stable (ISS) synchronization method for a general class of chaotic systems with disturbances. Based on Lyapunov theory and linear matrix inequality (LMI) approach, for the first time, the ISS synchronization controller is presented not only to guarantee the asymptotic synchronization but also to achieve the bounded synchronization error for any bounded disturbance. The proposed controller can be obtained by solving a convex optimization problem represented by the LMI. Simulation studies are presented to demonstrate the effectiveness of the proposed ISS synchronization scheme.

6 illus, 28 ref

019989   Adegoke K;Buttner H (Physics Dep, Obafemi Awolowo Univ, 220005, Ile-Ife, Nigeria, Email: adegoke@rushpost.com) : Continous quantum phase transitions in the one-dimensional spin-1/2 axial next-nearest-neighbour ising model in two orthogonal magnetic fields. Pramana J Phys 2010, 74(2), 293-306.

Investigated the one-dimensional spin-1/2 axial next-nearest-neighbour Ising (ANNNI) model in two orthogonal magnetic fields at zero temperature. There are four different possible ground state configurations for the ANNNI model in a longitudinal field, in the therniodynamic limit. The inclusion of a transverse field introduces quantum fluctuations which destroy the existing spin order along certain critical lines. The effects of the fluctuations in three of the four ordered regions were investigated using the finite-size scaling technique. The phase boundaries of the ANNNI model in two orthogonal magnetic fields were thus determined numerically. For certain limits of the Hamiltonian we compared the obtained results with the existing literature and our results were in good agreement with the results in the existing literature.

7 illus, 1 table, 29 ref

018679   Padmanabhan T (NO, IUCAA, Pune) : Dawn of science, 4. archimedes. Resonance 2010, 15(9), 774-8.

7 illus, 2 ref

018678   Kuriakose V C;Porsezian K (Physics Dep, Cochin Univ of Science and Technology, Kochi-682 022, Email: vckuriakose@gmail.com) : Elements of optical solitons. Resonance 2010, 15(7), 643-66.

Existence of solitons in nonlinear optical fibres was first predicted by Hasegawa and Tappert in 1973 and its experimental verification came in 1980. Ever since, both experimental and theoretical physicists have shown keen interest in this topic due to its versatile applications. Optical solitons are formed due to the balance between the group velocity dispersion and the self phase modulation in the anomalous dispersion regime, and the governing wave equation is the Nonlinear Schrodinger (NLS) equation. Optical solitons can exist in various systems like photonic crystal fibres, bulk materials like photorefractive materials, photopolymers, etc. What follows is an introduction to optical soiltons and their applications.

9 illus, 6 ref

018677   Deshmukh P C;Libby J (Physics Dep, Indian Institute of Technology, Madras, Chennai-600 036, Email: pcd@physics.iitm.ac.in) : Symmetry principles and conservation laws in atomic and subatomic physics-2. Resonance 2010, 15(10), 926-40.

This article is the second part of our review of the important role that symmetry plays in atomic and subatomic physics. We will concentrate on the discrete symmetries - parity, charge conjugation, and time reversal - that have played a significant part in the development of the 'standard model' of particle physics during the latter part of the 20th century. The importance of experimental tests of these symmetries, in both atomic and particle physics, and their sensitivity to new phenomena is also discussed. To conclude, we describe how 'symmetry breaking' in the standard model leads to the generation of mass via the Higgs mechanism and how the search for evidence of this symmetry violation is one of the principal goals of the Large Hadron Collider, which began operating at CERN, Switzerland in 2009.

6 illus, 14 ref

018676   Deshmukh P C;Libby J (Physics Dep, Indian Institute of Technology, Madras, Chennai-600 036, Email: pcd@physics.iitm.ac.in) : Symmetry principles and conservation laws in atomic and subatomic physics - 1. Resonance 2010, 15(9), 832-42.

The whole theoretical framework of physics rests only on a few but profound principles. Wigner enlightened us by elucidating that "It is now natural for us to try to derive the laws of nature and to test their validity by means of the laws of invariance, rather than to derive the laws of in-variance from what we believe to be the laws of nature." Issues pertaining to symmetry, invariance principles and fundamental laws challenge the most gifted minds today. These topics require a deep and extensive understanding of both 'quantum mechanics' and the 'theory of relativity'. We attempt in this pedagogical article to present a heuristic understanding of these fascinating relationships based only on rather elementary considerations in classical and quantum mechanics. An introduction to some fundamental considerations regarding continuous symmetries, dynamical symmetries (Part 1), and discrete symmetries (Part 2) (parity, charge conjugation and time-reversal), and their applications in atomic, nuclear and particle physics, will be presented.

3 illus, 8 ref

018675   Chatterjee S;Gadad S S;Kundu T K (NO, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore) : Atomic force microscopy a tool to unveil the mystery of biological systems. Resonance 2010, 15(7), 622-42.

Focuses on one of the promising and emerging nanolevel imaging techniques: Atomic Force Microscopy (AFM). In recent studies, AFM has been extensively used to understand intricate biological phenomena like prokaryotic and eukaryotic genome organization, different DNA transaction activities, protein chaperoning and also protein-nucleic acid organization in viruses.

8 illus, 6 ref

009103   Singh K M (NO, , Grace House, Mainpura, Patna-800 001) : Device working on gravitational force. 0000, (NULL), (NULL).

009102   Venkata Ramana G;Rajagopal E;Manohara Murthy N (Dep of Physics, Sri Krishnadevaraya University, Anantapur - 515 003) : Studies on the effect of mixed electrolyte on the temperature of sound velocity maximum of water. J pure appl Ultrasonics 2001, 23(3-4), 51-7.

The effect of mixed electrolytes (NaCl + KCl), (NaBr + KBr) and (NaI + KI) on the temperature of sound velocity maximum (TSVM) of water, T_-w has been studied by determining the ultrasonic velocity. The velocity measurements were carried out at ≡2°C intervals over a range of 5°C on either side of TSVM of the solution. The accuracy in fixing TSVM is <154>-w of pure water due to the addition of mixed electrolytes, ΔT_str has been found to be negative and increasing with concentration of mixed electrolytes. At any given concentration ΔT_str of (NaI+KI)> (NaBr+KBr)>(NaCl+KCl). The results are explained in terms of enhancement in the structure breaking nature of K⁺ and drvrease in the structure promoting nature of Na⁺ due to the presence of halide ions. The changes in the structural propensities of Na⁺ and K⁺ are found to depend on the structure breaking efficiency of halide ions present in the aqueous mixed electrolyte solutions.

6 illus, 3 tables, 25 ref

009101   Sidkey M A;Yehia A A;Abd el Malak N A;Gaafar M S (NO, National Institute for Standards, El Haram (Egypt) National Research C, Egypt) : Elastic properties of some rubber blend. J pure appl Ultrasonics 2001, 23(3-4), 43-50.

Elastic properties of Adiprene CM - NBR, Adiprene E- NBR Adiprene E - NR, and Adiprene CM - NR blend system samples were calculated from longitudinal and transverse ultrasonic velocities measured experimentally using pules echo technique, and densities of the blend system samples measured by the immersion method. For compatible solid blend systems, the relations between the elastic moduli and blend composition is represented by straight lines. This behaviour indicates that there is no phase separation taking place in these blend systems. Such behaviour can be interpreted as being due to strong interactions via the chemical combinations between the two parent blend constituents to form a single phase structure and consequently, can be used as indication for compatibility. For the incompatible blend system, the relations between the elastic moduli and composition of the blend system deviate from linearity. The deviation from linearity behaviour in these curves can be explained on the basis that the macromolecular mixing of the two parent rubber components of this blend system is very poor and consequently, the presence of two phases.

8 illus, 36 ref

009100   Sathhiyan S;Ravichandran R;Ravikumar M (Dep of Radiation Physics, Kidwai Memorial Institute of Oncology, Hosur Road, Bangalore -560 029) : Measurements of radiation absorbed doses in high energy radiotherapy beam : a comparison of different calibration protocol. J med Phys 2003, 28(1), 18-22.

The radiation output calibration of external beam radiotherapy machines based on the ionization chamber measurement is an important task of the medical physicists. Earlier, an in-air calibration measurement was practiced for ⁶⁰Co beam and the water calibration methods were limited to linear accelerators only. In order to have a traceability of dosimetry between calibration laboratories and users, various protocols were introduced over two decades. The absorbed dose to air calibration (N_d.air) factor was explained in TG-21 and TRS-227 protocols which were later replaced by absorbed dose to water calibration (N_D,w) in TG-51 and TRS-398 protocols. In this context, it has compared in-air measurements with in-water measurements using above protocols for the ⁶⁰Co and ¹³⁷Cs beams, and the results agree within ±2%. The photon beam output values measured using TRS-277 and TRS-398 formalisms were within ±1% for the ⁶⁰Co beam, 6MV and 18 mv x-ray photon beams. The measurements using a cylindrical chamber (TRS-277) and parallel plate chamber (TRS-381) have shown good agreement for high energy photons and electrons. The TLD audit carried out for all the photon beams and the results are within ±5%.

3 illus, 4 tables, 8 ref

009099   Rose J V R;Paul Ravindran B;Rabi Raja Singh I (Dep of Radiation Oncology, Christian Medical College, Vellore - 632 004) : Modified ferrous ammonium sulphate benzoic acid xylenol orange clinical dosimeter (MFBX - clinical dosimeter). J med Phys 2003, 28(1), 23-9.

Ferrous ammonium sulphate benzoic zcid xylenol orange dosimeter (FBX) developed to detect and measure radiation doses in the clinical range recommended the use of triple distilled water for its preparation and its shelf life was claimed to be two weeks. To be of use as a clinical dosimeter for routine use, preparation of this dosimeter with distilled water generated in the pharmacy department of the hospital was tried. The rapid auto-oxidation encountered forced to undertake a systematic experimental study. The modification made in the concentration of sulphuric acid significantly increased its shelf life and hence it is referred to modified FBX (Mfbx). Doses measured under various conditions were checked against ionization measurements with secondary standard dosimeter to show that MFBX can be used with confidence as a reliable clinical dosimeter. It is shown that measurement of doses with volumes as small as 0.6-0.7 ml is possible. Besides, MFBX can be used for output check as well as for verifying beam parameters of teletherapy units.

6 illus, 10 tables, 8 ref

009098   Ramanujan R V (Sch of Mater Engg., nanyang Avenue, Nanyang Technological Univ, Singapore-639 798) : Nanostructured electronic and magnetic materials. Sadhana 2003, 28(129-130), 81-96.

Research and development in nanostructured materials is one of the most intensely studied areas in science. As a result of concerted R & D efforts, nanostrured electronic and magnetic materials have achieved commercial success. Specific examples of novel industrially important nanostured electronic and magnetic materisl are provided. Advantages of nanocrystalline magentic materials in the context of both materials and devices are discussed. Several high technology examples of the use of nanostructured materials are described and the examples of sol gel, rapid solidification and powder injection moulding as potential processing methods, for making nanostructured materials are outlined. Some opportunities and challenges are discussed.

6 illus, 2 tables, 11 ref

009097   Paul A;Gupta SC;Pant CC (Geology Dep, Kumaun University, Nainital-263 002) : CODA Q estimates for Kumaun Himalaya. Proc Indian Acad Sci-Earth Planet Sci 2003, 112(4), 569-76.

Coda Q (Qc) estimates for the Kumaun Himalaya region have been obtained in high frequency range. Local earthquakes, recorded by digital seismic network in the region, which fall in the epicentral distances range of 10 to 80 km and with a local magnitude range of 1.4 to 2.8 have been used. The coda waves of 30 sec window length, filtered at seven frequency bands centrered at 1.5, 3, 6, 12, 18 and 24 Hz, have been analysed using the single backscattering model. The values of Qc estimates vary from 65 to 283 at 1.5Hz to 2119 to 3279 at 24.0 Hzwhich showed that Qc is frequency dependent and its value increases as frequency increases. A frequency-dependent Qc relationship , Qc=(92±4.73) f^(1.07±0.23), is obtained for the region representing the average attenuation characteristics of seismic waves for Kumaun Himalaya region.

3 illus, 4 tables, 13 ref

009096   Pal M;Chakravorty D (NO, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032) : Nancrystalline magnetic alloys and ceramics. Sadhana 2003, 28(129-130), 283-97.

Magnetic properties of materials in their nanocrystallie state have assumed signficance in recent years because of their potential applications. A number of tenchniques have been used to prepare nanocrystalline magnetic phases. Melt spinning, high energy ball milling, sputtering, glass ceramization and mlecular beam epitaxy are some of the physical methods used so far. Among the chemical methods, sol-gel and co-precipitation routes have been found to be convenient. Ultrafine particles of both ferro- and ferri-magnetic systems show superparamagnetic behaviour at room temperature. Coercivity (H_c) and maximum energy product (BH)_max of the magnetic particles can be changed by controlling their sizes. All these aspects in the case of nanocrystalline magnetic systems-both metallic and ceramics have been reviewed.

4 illus, 2 tables, 63 ref

009095   Padmanabhan K A (NO, Inst of Nanotechnology, Res Cen for Technol. and Environmenta, P O Box 3640, Karlsruhe, Germany) : Thermally assisted deformation of structural superplastics and nano structured materials: a personal perspective. Sadhana 2003, 28(129-130), 97-113.

Optimal structural superplasticity and the deformation of nanostructured materials in the thermally activated region are regarded as being caused by the same physical proces. In this analysis, grain/interphase boundary sliding controls the rate of deformation at the level of atomistics. Boundary sliding develops to a mesoscopic level by plane interface formation involving two or more boundaries and at this stage the rate controlling step is boundary migration. In other words, unbalanced shear stresses present at the grain/interphase boundaries ensure that near-random grain rotation is also a non-rate controlling concomitant of this mechanism. Expressions have been derived for the free energy of activation for the atomic scale rate controlling process, the threshold stress that should be cross for the commencement of mesoscopic boundary sliding, the inverse Hall-Petch effect and the steady state rate equation connecting the strain rate to the independent variables of stress, temperature and grain size. Beyond the point of inflection in the log stress-log strain rate plot, climb controlled multiple dislocation motion within the grains becomes increasingly important and at sufficiently high stresses becomes rate controlling. The predictions have been validated experimentally.

8 illus, 27 ref

009094   Murty B S;Datta M K;Pabi S K (Dep of Metall and Mater Engg, Indian Inst of Technol, Kharagpur-721 302) : Structure and thermal stability of nanocrystalline materials. Sadhana 2003, 28(129-130), 23-45.

Nanocrystalline materials, which are expected to play a key role in the next generation of human civilization, are assembled with nanometre-sized "building blocks" consisting of the crystalline and large volume fractions of intercrystalline components. In order to predict the unique properties of nanocrystalline materials, which are a combination of the properties of the crystalline size. In addition, study of the thermal stability of nanocrystalline materials against signficant grain growth is both scientific and technological interest. A sharp increase in grain size (to micron levels) during consolidation of nanocrystalline powders to obtain fully dense materials may consequently result in the loss of some unique properties of nanocrystalline materials. Therefore, extensive interest has been generated in exploring the size effects on the structure of crystalline and intercrystalline region of nanocrystalline materials, and the thermal stability of nanocrystalline materials against significant grain growth. Structure and stability of nancrystalline materials have been discussed.

20 illus, 2 tables, 115 ref

009093   Jayasree CS;Renuka G;Venugopal C (Physics Dep, University of Kerala, Kariavattom, Trivandrum - 695 581) : Ion acoustic instability of particles, density, anomalous resistivity and parallel electric field in the auroral region. Proc Indian Acad Sci-Earth Planet Sci 2003, 112(4), 559-67.

The magnetic field perturbations interpretatable as field aligned current (FAC) layers and the electrostatic turbulence possibly due to electrostatic ion acoustic instability driven by these currents are shown. The critical drift velocity of Hot Plasma Torus (HPT) electrons and the growth rate of ion acoustic wave as a function of electron to ion temperature ratio (T_e/T_i) for low the high current denstities and energy of HPT electrons are found out. The intense FAC destabilizes the ion acoustic wave and the resultant electrostatic turbulence high power dissipation. The anomalous resistivity 104, potential difference along the auroral field lines V_<157>, intensity of electric field turbulence E_<157> and power produced per unit volume P are computed. It is found that the change in westward magnetic perturbation increases J_<157>, η, V_<157>, E_<157> and P. Hence HPT electrons are heated and accelerated due to power dissipation during magnetically active periods in the aurorals region. Concerning, applications, such HPT electrons can be used in particle accelerators like electron ring accelerator, smokatron etc.

9 illus, 18 ref

009092   Divakar R;Raghunathan V S (Physical Metallurgy Section, Material Characterisation Group, Indira Gandhi Centre for Atomic Resea, Kalpakkam-603 102) : Characterisation of interfaces in nanocrystalline palladium. Sadhana 2003, 28(129-130), 47-62.

Structures of grain boundaries and triple line junctions in nanocrystalline materials are of interest owing to large fractions of atoms in nanocrystalline materials being at these interfacial positions. Grain boundry and triple line junciton structures in nanocrystalline palladium have been studied using high-resolution transmission electron microscopy (HRTEM). The main microstructural features observed include the varying atomic structures of grain boundaris and the presence of disordered regions at triple line junctions. Also there is variation in lattice parameters in different nanocrystalline grains. Geometric phase analysis is used to quantify atomic displacements within nancrystalline grains. Displacement fields thus detected indicate links to the interface structures.

6 illus, 1 table, 35 ref

009091   Chaddah P (Scryogenics and Superconductivity Section, Centre for Advanced Technology, Indore-452 013) : Critical current densities in superconducting materials. Sadhana 2003, 28(129-130), 273-82.

Recent research in the area of critical current densities (J_C in superconductors has been discussed. This included recent work on newly discovered superconductors, as well as on the magenetic-field dependence of J_C.

4 illus, 35 ref

009090   Cahn R W (Dep of Material Sci. and Metallurgy, Cambridge University, Pembroke St., Cambridge CB2 3QZ, England) : Freedom and fashion in material science and engineering. Sadhana 2003, 28(129-130), 17-22.

Analyses the rate at which a new scientific discovery is taken up around the world and further pursued, and the factors that govern such take-up, with special focus on freedom and fashion.

ia10 ref

009089   Bharathi A;Hariharan Y;Balaselvi J;Sundar C S (Mater Sci Div, Indira Gandhi Centre for Atomic Research, Kalpakkam-603 102) : Superconductivity in MgB₂: Phenon modes and influence of carbon doping. Sadhana 2003, 28(129-130), 263-72.

Following a breif overview, results of investigations on phonon modes in MgB₂, and superconducting transition in carbon doped MgB₂ are presented. The superconducting transition temperature in MgB_2-xX_x as obtained from susceptibility and resistivity measurements is observed to decrease systematically from 39.4 K for x=0 to 26 K for x=0.5. It is shown the changes in lattice volume, as obtained from X-ray diffraction measurements, can account only partially for the observed decrease in T_c. The observed variation of T_c with carbon content is seen to correlate with the Debye temperatures, obtained from an analysis of the resistivity data. Investigation of the phonon modes in MgB₂, through infrared absorption measurements indicate three modes at 410, 475 and 560 cm^-1. The former two are associated with the infrared active modes, and the third component is associated with the Raman mode, that gets activated due to disorder. A study of the temperature dependence of these modes indicates no changes across the superconducting transition. The mode at 560 cm^-1 shows a signficant hardening and a corresponding decrease in linewidth, with the lowering of temperature, that can been accounted in terms of anharmonicity.

7 illus, 33 ref

009088   Alok Singh;Tsai A P (Physical Metallurgy Section, Materials Characterisation Group, Indira Gandhi Centre for Atomic Rese, Kalpakkam-603 102) : Melting behaviour of lead and bismuth nano-particles in quasicrystalline matrix - the role of interfaces. Sadhana 2003, 28(129-130), 63-80.

Nanmaterials are playing an increasingly imortant role in modern tecnologies. Interfaces are crucial in nanotechnology. The statbility of nanoparticles have been studied. Major emphasis is on understanding the effect of interfaces on melting. Melting behaviour of nanocrystalline interfaces created by embedding lead and bismuth nanparticles in quasicrystalline matrices, was studied. Sharply faceted and coherent interfaces can be related related to sharper melting transitions, while irregularly shaped and incoherent interfaces can be directly correlated with lowering of melting temperatures. It is shown that solid lead forms a high energy interface with phason strain-free quasicrystal (resulting in a lowering of the melting temperature) while bismuth forms a low energy interface with the quasicrystal (resulting in superheating, unusual for bismuth).

7 illus, 5 tables, 39 ref

000009   Sengupta A (NO, , ) : Performance of a thermodynamic constitutive model for granular materials. Indian Geotech J 2003, 33(4), 319-46.

A recently developed thermodynamic constitutive model for frictional materials has been reviewed. Its performance has been studied for sand and cemented sand along different stress paths for which the model was not calibrated. The stress-strain and volume change predicted by the model have been found to be reasonably close to the laboratory test results except for the cyclic and circular stress paths. The not so good performance of the model along cyclic and cir cular stress path is due to the absence of third invariance of stresses in the model formulations.

11 illus, 3 tables, 19 ref

000008   Saran S;Bhandari NM;Al-Smadi MMA (Civil Engg. Dep, Indian Insitute of Technology Roorkee, Roorkee-247667) : Analysis of eccentrically-obiquely loaded ring footings on sand. Indian Geotech J 2003, 33(4), 423-46.

Ring foundations (circular in plan with an annuli) are usually provided for tall circular structures like smoke stacks, cement silos, water towers, etc. A new method has been sugested to obtain the pressure-settlement and pressure-tilt characteristics of an actual ring footing, resting on sand, and subjected to ecentric inclined load using non-linear constitutive law of soil . A new concept of factor of safety has been introduced to encounter the use of stress equation based on the theory of elasticity. The pre-requisite of the method is the value of ultimate bearing capacity, which can be obtained from the approaches based on shear failure. The values of settlement and tilt may be read directly from pressure vs. settelement and pressure vs. tilt curves for the given pressure intesity. Therefore, the ring footing can be proportioned satisfying shear failure, settlement and tilt criterion.

11 illus, 2 tables, 19 ref

000007   Madhav MR;Umashankar B (Civil Engg. Dep, Indian Institute of Tehcnology, Kanpur-208 016) : Response of extensible reinforcement to transverse pull / displacement: linear subgrade behavior. Indian Geotech J 2003, 33(4), 397-421.

The geosyntheic reinforcement used in reinforced soil walls, reinforced soil slopes and a reinforced embankment etc. resists the destabilizing forces by mobilizing tensile forces along its length. In the existing desing procedures, the resistance mobilized due to only axial pull is considered in the analysis for stability of reinforced earth structures. However, the kinematics of failure clearly establishes that the reinforcement is displaced obliquely. The total resistance due to oblique pull / displacement is considered to be sum of the resistance due to transverse and axial pull/displacement. Considering a linear subgrade/fill but the reinforcement to be extensible, the resistance to transverse pull/displacement is modelled and estimated in this paper. It is established that the response due to transverse pull / displacement depends not only on the interface shear characteristics of the reinforcement but also on the deformational response of the ground. A relation is established between pullout resistance and transverse front end displacement. A parametric study quantifies the effects of stiffness of extensible reinforcement and thecompressibility of subgrade on the overall response due to transverse pull/displacement. The responses of extensible and inextensible reinforcemnts are comapred and contrasted. The pullout resistance for inextensible reinforcement under transverse displacement is shown to exceed that for extensible reinforcement.

21 illus, 2 tables, 25 ref

000006   Krishnamoorthy;Rao NBS;Anil DS (Civil Engg. Dep, Manipal Insitute of Technology, Manipal-576 119) : Non linear analysis of group of piles. Indian Geotech J 2003, 33(4), 375-95.

The load carrying capacity and load settlement behaviour of single pile and gourp of piles is obtained using nonlinear finite element analysis. A hypoelasticity constitutive model is used to model the behaviour of soil. To consider the reltive slip between soil and pile, the interface between the pile and soil is represented by an interface element. The pile is modeled using a two noded line element with one degree of freedom at each node. The pile is conncected to the soil through an interface element. The analysis is used to study the behaviour of single and group of piles are placed in square block and whentwo piles are placed in a row are studied. These studies are carried out for friction piles and end bearing piles. It is concluded from the study that the load carrying capacity of each pile in a group is less than that of the single pile. Further, as the spacing of pile decreses, the load carrying capacity of each pile in a group also decreases and settlement of the pile group increases. Also the effect of spacing is more significant when the piles are placed in block rather in a row. The effect of spacing is also more signficant in friction piles than in end bearing piles.

17 illus, 2 tables, 6 ref

007269   War T A;Chandan A;Rani Devi;Khosa S K;Bharti A (Physics and Electronics Dep, Jammu University, Jammu 180 006) : Importance of hexadecapole interactions in even-even germanium and selenium isotopes. Indian J pure appl Phys 2003, 41(12), 914-21.

Variation after projection (VAP) calculations in conjunction with Hartree-Bogoliubov (HB) ansatz have been carried out for germanium and selenium isotopes. In this framework, the yrast spectra with JΠ± 10⁺, B(E2) transition probabilities, quadrupole deformation parameter (β₂) have been obtained. The results of the calculation give an indication that, it is important to include the hexadecapole-hexadecapole component of the two-body interaction for obtaining various nuclear structure quantities in Ge and Se isotopes. Besides this, it is important to include 2d_5/2 orbit in valence space for making nuclear structure calculations in Ge-Se mass region.

4 illus, 4 tables, 32 ref