001088   Biswas D (Theoretical Phys Div, Bhabha Atom Res Cent, Mumbai-400 085, Email: malabika6@rediffmail.com) : Evolution of classical projected phase space density in billiards. Pramana J Phys 2005, 64(4), 563-75.

The classical phase space density projected on to the configuration space offers a means of comparing classical and quantum evolution. In this alternate approach that we adopt here, we show that for billiards, the eigenfunctions of the coarse-grained projected classical evolution operator are identical to a first approximation to the quantum Neumann eigenfunctions. Moreover, there exists a correspondence between the respective eigenvalues although their time evolutions differ.

5 illus, 22 ref

001087   Bhosale C S;Meena G S;Londhe A L;Jadhav D B; Puentedura O;Gil M (Indian Inst of Trop Meteorology, , Pune-411 008) : Variations of O₃, NO₂ and O₄ densities in association with NAO indices during winter/spring of 1993/94 and 1994/95 at sub-arctic station. Indian J Radio Space Phys 2004, 33(2), 104-14.

A study of the atmospheric trace constituents like O₃, NO₂ and O₄ has been made in the visible spectral region 550-595 nm. The data for the above study have been obtained from the daily observations of the light intensity taken at twilight hours in the early morning and evening by using an automatic spectrometer at the sub-Arctic station Reykjavik (64°N, 22.6°W) for the months December-April (winter/spring) of 1993/94 and 1994/95. The Differential Optical Absorption Spectroscopy (DOAS) technique has been used to obtain slant column density (SCD) of O₃, NO₂ and O₄ from the above light intensity. Further, vertical column densites (VCDs) of O₃ and NO₂ have also been calculated at solar zenith angle (SZA> 90° by dividing above SCD with a proper value of air mass factor. The results of the above analyses have shown that there exists a predominant daily variation in the VCDs of O₃ and VCDs of NO₂ at both morning and evening twilight hours. There exists one oscillation within the daily variations of O₃ and NO₂; this oscillation is confined to the same period of 3-10 days (visual appearance). These periodic oscillations are found to have coincided with the oscillation of the stratospheric warm and cold episodes during the above period of observations. It is interesting to note that the evening twilight hour magnitudes of O₃ and NO₂ are slightly higher than those of the morning twilight hour magnitudes, but they are in phase with each other. The variations of the VCD O₃ and VCD NO₂ have been correlated with the North Atlantic oscillation (NAO) index. The correlation coefficients are +0.21 and +0.25 between VCD O₃ and NAO index in 1993/94 and 1994/95, respectively. But VCDs of NO₂ seldom show any relationship with NAO index. Also, the daily variations in SCDs of O₄ are studied in connection with the different types of clouds prevailing at the Arctic station during winter/spring of 1993/94 and 1994/95. There exists strong variability of O₄ with variations of the type of clouds.

5 illus, 37 ref

001086   Basu B;Mazumdar A;Raha S;Saha S;Saha S K;Syam D (Dep of Phys, Bost Inst, Kolkata-700 009, Email: bbnandi@bosemain.boseinst.ac.in) : Characterization of some commercial polymers for the detection of massive cosmic ray particles. Indian J Phys 2005, 79(3), 279-83.

A particular brand (CENTURY deSmat, India) of overhead projector (OHP) film has been exposed to α-particle and fission fragments from ²⁵²Cf natural source in order to investigate its detection efficiency and charge sensitivity in comparison to the standard detector CR39, applying solid state nuclear track detection (SSNTD) technique. The results obtained indicate that the OHP films cannot detect particle with Z/β ≤ 35, but particles with Z/≤ ~ 900 - 1600 can be detected. The composition of the OHP film was determined. The high detection threshold identifies this particular material as a suitable candidate for setting up a large area array of detectors, aiming at the search of rare massive cosmic ray particles at mountain altitudes.

4 illus, 2 tables, 14 ref

001085   Bandyopadhyay J N;Lakshminarayan A (Phys Res Lab, , Navrangpura, Ahmedabad-380 009, Email: arul@physics.iitm.ac.in) : Entanglement production in quantized chaotic systems. Pramana J Phys 2005, 64(4), 577-92.

Quantum chaos is a subject whose major goal is to identify and to investigate different quantum signatures of classical chaos. Here authour study entanglement production in coupled chaotic systems as a possible quantum indicator of classical chaos. Authors use coupled kicked tops as a model for our extensive numerical studies. Authour find that, in general, chaos in the system produces more entanglement. However, coupling strength between two subsystems is also a very important parameter for entanglement production. Here Authour show how chaos can lead to large entanglement which is universal and describable by random matrix theory (RMT). Authors also explain entanglement production in coupled strongly chaotic systems by deriving a formula based on RMT. This formula is valid for arbitrary coupling strengths, as well as for sufficiently long time. Authors investigate also the effect of chaos on the entanglement production for the mixed initial state. Authors find that many properties of the mixed-state entanglement production are qualitatively similar to the pure state entanglement production. Authors however still lack an analytical understanding of the mixed-state entanglement production in chaotic systems.

5 illus, 28 ref

001084   Arjuna gowda K v;Khan I A;Kulkarni M V; Shivaprakash N C (Dep of Phys, S J C Inst of Technol, Chickballapur, Kolar, Karnataka) : Structure of 3'-5'-dimethyl-6-methoxy 4-2'-benzo[b] furanyl coumarin. Indian J Phys 2005, 79(3), 289-92.

The title compound belongs to a family of biheterocyclic benzofuranyl coumarins. The crystal structure has been determined at room temperature using X-ray diffraction intensity data. Plate like colourless crystals are triclinic, spacegroup PI with unit cell dimensions a=7.640(13)Å, b=9.659(6)Å, c=11.955(8)Å, α = 85.27(7)<144>

2 illus, 4 tabeles, 8 ref

001083   Ambika G;Menon K;Harikrishnan K P (Dep of Phys, Maharaja's Coll, Cochin-682 011, Email: ambika@iucaa.ernet.in) : Aspects of stochastic resonance in Josephson junction, bimodal maps and coupled map lattice. Pramana J Phys 2005, 64(4), 535-42.

Authors present the results of extensive numerical studies on stochastic resonance and its characteristic features in three model systems, namely, a model for Josephson tunnel junctions, the bistable cubic map and a coupled map lattice formed by coupling the cubic maps. Some interesting features regarding the mechanism including multisignal amplification and spatial stochastic resonance are shown.

9 illus, 23 ref

001082   Ahuja B l;Malhotra H;Sharma M (Dep of Phys, Coll of Sci Campus M L Sukhadia Univ, Udaipur-313 001, Email: blahuja@yahoo.com) : Compton scattering study of Samarium. Indian J Phys 2005, 79(3), 239-43.

The isotropic Compton profile of samarium is presented in this work. The measurement has been made using 661.65 keV 20 Ci ^137>Cs Compton spectrometer. The results are compared with calculations based on remormalised-free-atom (RFA) and free electron models. It is seen that the RFA calculation for configuration 4159>⁶5d⁶s² (with e^--e^- correlation) is better agreement with the experiment. Derived the cohesive energy of samarium using RFA Model. A comparison of RFA based cohesive energy with the available band structure data shows the applicability of the RFA model in calculating the electronic structure of rare-earth elements.

3 illus, 2 tables, 34 ref

000180   Vengadesan K;Gautham N (Dep of Crystallography and Biophys, Univ of Madras, Chennai-600 025, Email: gautham@unom.ac.in) : A new conformational search technique and its applications. Curr Sci 2005, 88(11), 1759-70.

The computational identification of the low energy structures of a peptide from its sequence alone has been a problem of major interest for many years. It is not an easy task even for small peptides, due to the multiple minima problem and combinatorial explosion. A number of conformational search algorithms have been developed in the past for this purpose. An algorithm that addresses this problem has been developed. In statistical experimental design, mutually orthogonal latin square (MOLS) are used to systematically sample the space of the variables. This allows the experimenter to conduct the experiment with a relatively small number of runs, instead of examining all possible combinations of values of the variables. Whether the problem of searching for minimum energy molecular structure on the potential energy surface could also be similarly solved by MOLS sampling has been considered. This has led to the development of a conformational search algorithm. The work carried out using the MOLS search technique over the last decade has been reviewed.

8 illus, 3 tables, 58 ref

000179   Srivastava A K;Prasad G;Vinay Kumar;Chawdhuri M B;Ram Prakash (NO, Inst for Plasma Res Bhat, Gandhinagar-382 428) : Experimental studies on atmospheric pressure glow discharge for drag reduction and microwave invisibility. J Aerospace Sci Technol 2005, 57(1), 17-23.

Absorption and reflection of microwaves from plasma with electron density gradients and reduction of frictional drag force on moving aircrafts are the important issues of atmospheric pressure plasma applications. For these purposes several thermal and non-thermal plasma sources have been developed that work near atmospheric pressure. The characterization of these plasmas has also been done by many researchers using mostly spectroscopic techniques. The Langmuir probe diagnostic, inspite of its theoretical limitation at high collisional regime, has also been reported in many experiments to characterize high-pressure plasmas. It was reporting the comparison of MO diagnostic techniques i.e. Langmuir probe and emission spectroscopy for atmospheric pressure glow discharge plasma in helium. For the measurement of plasma parameters, ramped probe I-V characteristics curves were used for probe diagnostics and line intensity ratios were used for spectroscopic diagnostics. An attempt has been made to crosscheck the measurements using different techniques for their validation. The variation of the plasma parameters i.e. electron density and temperature with external tunable parameters viz. applied voltage and frequency is also investigated to find the scaling of plasma parameters with external controls. Estimated electron density is <126> 10¹¹ cm^-3 and electron temperature is <126>10 eV. Measured plasma parameters indicate suitability of the plasma which can be exploited for microwave invisibility.

4 illus, 1 table, 34 ref

000178   Samarasekara P;Mallika Arachchi M A K; Abeydeera A S;Fernando C A N;Disanayake A S;Rajapakse R M G (Phys Dep, Univ of Ruhuna, Matara, Sri Lanka, Email: pubudus@phy.ruh.ac.lk) : Photocurrent enhancement of d.c. sputtered copper oxide thin films. Bull Mater Sci 2005, 28(5), 483-6.

Copper oxide (CuO) thin films with phtocurrent as high as 25 μA/cm² were deposited on conductive glass substrates using d.c. reactive sputtering. This was the highest reported photocurrent for sputtered p-type copper oxide measured in the electrolyte KI. The photocurrent drastically increased up to 25 μA/cm² as the sputtering pressure and the substrate temperature were increased upto to 8.5 mber and 192°C, respectively. All the synthesized films contained single phase of CuO in this range of pressure and substrate temperature. Variation of the photocurrent, photovoltage, structure and absorbance with deposition conditions were studied in detail.

7 illus, 9 ref

000177   Ratnakaram Y C;Lakshmi J;Chakradhar R P S (Phys Dep, Univ P.G. Cent, Kavali-524 201, Email: Ratnakaram_YC@yahoo.co.in) : Optical absorption and fluorescence properties of Er<. Bull Mater Sci 2005, 28(5), 461-5.

Spectroscopic properties of Er³⁺ ions in sodium borate glass have been studied. The indirect and direct optical band gaps (E_opt) and energy level parameters (Racah (E¹, E₂ and E₃), spin-orbit (ξ_4f) and configurational interaction (α)) are evaluated. Spectral intensities for various absorption bands of Er³⁺ doped sodium borate glass are calculated. Using Judd-Ofelt intensity parameters (Ω₂, Ω₄, Ω₆), radiative transition probabilities (A), branching ratios (β) and integrated absorption cross sections (Σ) are reported for certain transitions. The radiative lifetimes (τ_R) for different excited states are estimated. From the fluorescence spectra, the emission cross section (<125>_p) for the transition, ⁴I₁₃₂ → ⁴I₁₅₂ is reported.

3 illus, 3 tables, 15 ref

000176   Patel K;Prajapati J;Vaidya R;Patel S G (Phys Dep, , Sardar Patel University) : Optical and electrical properties of ZrSe₃ single crystals grown by chemical vapour transport technique. Bull Mater Sci 2005, 28(5), 405-10.

Single crystals of the lamellar compound, ZrSe₃, were grown by chemical vapour transport technique using iodine as a transporting agent. The grown crystals were characterized with the help of energy dispersive analysis by X-ray (EDAX), which gave confirmation about the stoichiometry. The optical band gap measurement of as grown crystals was carried out with the help of optical absorption spectra in the range 700-1450 nm. The indirect as well as direct band gap of ZrSe₃ were found to be 1.1 eV and 1.47 eV, respectively. The resistivity of the as grown crystals was measured using van der Pauw method. The Hall parameters of the grown crystals were determined at room temperature from all effect measurements. Electrical resistivity measurements were performed on this range. The activation energy and anisotropy measurements were carried out for this crystal. Pressure dependence of electrical resistance was studied using Bridgaman opposed anvils set up up to 8 GPs. The semiconducting nature of ZrSe₃ single crystal was inferrecd from the graph of resistance vs. pressure. The results obtained are discussed in detail.

6 illus, 3 tables, 19 ref

000175   Narendra Babu S;Bhimasankaram T;Suryanarayana S V (Phys Dep, Osmania Univ, Hyderabad-500 007, Email: narendra_sim@yahoo.co.in) : Magnetoelectric effect in metal-PZT laminates. Bull Mater Sci 2005, 28(5), 419-22.

Magnetoelectric (ME) composites are two-phase composites consisting of piezoelectric and piezomagnetic materials as the participating constituents. These magnetoelectric composites when placed under external magnetic field, show electrical polarization (magnetoelectric output). The ME coupling is mediated by mechanical stress. In the study, author synthesized Ni/PZT/Ni and Fe/PZT/Fe layered composites for studying their ME output by dynamic magnetoelectric set up in which both d.c. and a.c. magnetic fields can be varied. The ME output obtained in these composites are higher than those obtained in 40% Ni_0.97Co_0-43Mn_0.01Fe_3-9O₄ + 60% BaTi_1.42O_3.04. The results with varying d.c. and a.c. magnetic fields are presented.

5 illus, 2 tables, 19 ref

000174   Kishore V;Saraswat V K;Saxena N S;Sharma T P (Semiconductor and Polym Sci Laboratory, Univ of Rajasthan, Jaipur-302 004, Email: n_s_saxena@rediffmail.com) : Structural and electrical measurements of CdZnSe composite. Bull Mater Sci 2005, 28(5), 431-6.

The I-V characterization and the electrical resistivity of selenium rich Se₈₅Cd_15-aZn_x (x = 0, 3, 7, 11 and 15) system at room temperature have been studied. Samples were obtained using melt cooling technique. So prepared samples were then characterized in terms of their crystal structure and lattice parameter using X-ray diffraction method. The materials were found to be polycrystalline in nature, having zinc blend structure over the whole range of zinc concentration. The electrical resistivity of the samples with composition at room temperature has been found to vary between maximum 2.7 x 10⁸ Ω m and minimum 7.3 x 10⁵ Ω m and shows a maximum at 3 at. wt. % of Zn. The carrier activation energy of the samples with composition has also been determined and found to vary from 0.026 eV to 0.111 eV.

6 illus, 1 table, 15 ref

000173   Joseph B;Manoj P K;Vaidyan V K (Phys Dep, St. Joseph's Coll, Calicut-673 008, Email: benny_chellamkottu@rediffmail.com) : Studies on preparation and characterization of indium doped zinc oxide films by chemical spray deposition. Bull Mater Sci 2005, 28(5), 487-93.

Preparation of indium doped zinc oxide films is discussed. Variation of structural, electrical and optical properties of the films with zinc acetate concentration and indium concentration in the solution are investigated. XRD studies have shown a change in preferential orientation from (002) to (101) crystal plane with increase in indium dopant concentration. Films deposited at optimum conditions have a low resistivity of 1.33 x 10^-4 Ωm with 94% transmittance at 550 nm. SEM studies have shown smooth polycrystalline morphology of the films. Figure of merit is evaluated from electrical resistivity and transmittance data.

8 illus, 5 tables, 22 ref

000172   Harinder Pal Singh;Rajiv Kumar;Sekhon S S (Appl Phys Dep, Guru Nanak Dev Univ, Amritsar-143 005, Email: sekhon_apd@yahoo.com) : Correlation between ionic conductivity ad fluidity of ploymer gel electrolytes containing NH₄CF₃SO₃. Bull Mater Sci 2005, 28(5), 467-72.

Nonaqueous polymer gel electrolytes containing ammonium triflate (NH₄CF₃SO₃) and dimethyl-acetamide (DMA) with polymethylmethacrylate (PMMA) as the gelling polymer have been synthesized which show high value of conductivity (- 10^-2 S/cm) at 25ξC. The conductivity of polymer gel electrolytes containing different concentrations of NH₄CF₃SO₃ shows a small decrease with the addition of PMMA and this has been correlated with the variation of fluidity and these gel electrolytes. The small decrease in conductivity with PMMA addition shows that polymer plays the role of stiffener and this is supported by FTIR results which also indicates the absence of any active interaction between polymer and NH₄CF₃SO₃ in these gel electrolytes.

9 illus, 24 ref

000171   Gupta S K;Deshpande R D (Phys Res Laboratory, , Navrangpura, Ahmedabad-380 009) : Isotopes for water resource management in India. Himalayan Geol 2005, 26(1), 211-22.

The application of isotopes can advantageously supplement not only the data collection but also improve understanding of the water system dynamics and interactions between various reservoirs. Because of their inherent nature, isotopes of oxygen and hydrogen in particular, label the water flowing through the components of the system in a very characteristic manner and respond to the hydrological processes (e.g. evaporation, transpiration, mixing etc.) in quantifiable manner. Similarly, isotopes of other dissolved elements also label the water, depending on the regional characters of aerosols /soils /rocks etc., and change concentrations in a quantifiable manner during passage through the hydrologic system either by radioactive decay or exchange and mixing processes. Because of these characteristics, isotopic measurements yield unique information about hydrologic systems such as residence time, origin of vapour /water mass, flow rate, flow paths etc. - information that is difficult to obtain through other conventional means.

7 illus, 1 table, 50 ref

000170   Brahmam K V;Raja Reddy D;Reddy B K (Directorate of Advanced Composites, Advanced Systems Laboratory, , Kanchanbagh, Hyderabad-500 058) : Crystal growth and reflectivity studies of Zn_1-x Mn_x TE crystals. Bull Mater Sci 2005, 28(5), 411-14.

Single crystals of Zn_1-xMn_xTe were prepared by vertical Bridgman crystal growth method for different concentrations of Mn. Chemical analysis and reflectivity studies were carried out for compositional and band structure properties. Microscopic variation in composition between starting and end compounds was observed from EDAX analysis. Linear dependence of fundamental absorption edge (E_o) as a function of Mn concentration (x) was expressed in terms of a straight line fit and a shift in E_o towards higher energy was observed in reflectivity spectra of Zn_1-xMnTe.

6 illus, 2 tables, 10 ref

000169   Bhattacharyya S;Das S K;Mitra N K (Chem Technol Dep, Calcutta Univ, Kolkata-700 009, Email: swapan@cgcri.res.in) : Effect of titania on fired characteristics of triaxial procelain. Bull Mater Sci 2005, 28(5), 445-52.

Titania was progressively added in the range 3-9 wt% into a triaxial porcelain body consisting of clay, quartz and feldspar. The composed bodies were heated at five different temperatures in the range 1200-1400°C and their fired properties as well as phases evolved were studied. The results revealed that beyond 1300°C, formation of more liquid phases caused bloating in samples which led to generation of pores. This effect is more pronounced in TiO₂ containing samples. In the system, 1300°C appeared to be the optimum temperature at which porosity was almost negligible and strength was maximum (45 MPa), particularly in presence of TiO₂. From the results of XRD studies, it was revealed that quartz content primarily decreased with increase in TiO₂ content due to excess glass formation and its subsequent dissolution. Mullite content increased with increase in TiO₂ content. No significant effect was observed beyond 6 wt % addition. Micro-structure primarily showed the presence of quartz grain and cluster of smaller sized primary mullite crystals in both the samples without and with TiO₂. Very few secondary mullite crystals were also observed. SEM picture of sample containing 9 wt % TiO₂ showed some grain boundary crack due to cooling stress generated in the glassy phase. The drastic reduction of residual strength after 8 cycles of heating at 800°C and cooling...

6 illus, 3 tables, 18 ref

000168   Assencia A A;Mahadevan C (Phys Res Cent, S.T. Hindu Coll, Nagercoil-629 002, Email: mahad@sancharnet.in) : D.C. electrical conductivity measurtments on ADP single crystals added with simple organic compounds. Bull Mater Sci 2005, 28(5), 415-18.

Pure and impurity added (with urea and thiourea) and single crystals were grown by the free evaporation method. D.C. electrical conductivity measurements were carried out along both the unique axis and perpendicular directions at various temperatures ranging from 40-150°C by the conventional two-probe method. Activation energies were also determined. The study indicates that the conductivity increases with the increase in impurity concentration and temperature.

4 illus, 2 tables, 12 ref

024164   Yadav U (Physics Dep, A.L.Y. College, Tribeniganj, Supaul, Bihar) : Theoretical study of scattering from an elliptical microstrip antenna on moment method. Bull pure appl Sci-Sect D 2006, 25(2), 101-7.

Solution to the problem of plane wave scattering by an elliptical microstrip patch on a grounded dielectric substrate is presented. The model does not include the microstrip feed, and thus does not include the so-called "antenna mode" component of the scattering. The solution begins by formulating an electric field integral equation for the surface current density on the microstrip patch. The integral equation is solved using the method of moments.

2 illus, 8 ref

024163   Thomas Joseph Prakash J;Kumararaman S (Physics Dep, Thanthai Hans Roever College, Perambalur-621 212, Email: armyjprl@yahoo.co.in) : Crystal growth and characterization of ZTS - Zinc (TRIS) thiourea sulphate - Z_n [CS(CS (NH₂)₂)₃] SO₄ - a semi organic NLO material - pH (4.3). Bull pure appl Sci-Sect D 2006, 25(2), 75-82.

Zinc (tris) thiourea sulphate crystal are good second harmonic generators (SHG) having appreciable semiorganic non linear optical (NLO) material has been synthesized at 30°C. Good quality single crystals with size 12 x 8 x 5 mm³ were grown by slow evaporation technique within 25 days with approximate growth rate of 0.5 mm/day. The grown crystals have subjected to single crystal X-ray diffraction to determine the unit cell dimensions and morphology. The TGA and DTA that the material has good thermal stability. FTIR analysers explain the inclusion of the metallic impurities. The UV-Vis spectrum shows that the materials has wide optical transparency in the entire visible region. The SHG confirmed by Kurtz powder method. The birefringence of the crystal was measured in the visible .region and it was found to vary the wave length. The Microhardness test carried out and the load dependent hardness was measured.

6 illus, 1 table, 15 ref

024162   Sharma D R;Arun Vijayakumar D (Vacuum and Pressure Standards, National Physical Laboratory, New Delhi-110 012) : Re-evaluation of measurement uncertainty of ultrasonic interferometer manometer, a primary pressure standard established at NPL, India. MAPAN 2006, 21(1), 37-46.

Ultrasonic Interferometer Manometer (UlM), a Primary Pressure Standard working in the range 1 Pa to 130 k Pa (abs), established at National Physical Laboratory, New Delhi, India, has been upgraded with a PC based data acquisition system incorporating a NI compatible GPIB interface card, a switch/ control unit (HP 3488A) and software written in TBASIC. After successful up-gradation and with the identification of 10 variable parameters and influencing factors, the expanded measurement uncertainty of this UIM was earlier evaluated as Q(O.0092 Pa, 4.1 ppm of reading) at k=2 as per the guidelines given in ISO guide on "Expression of Uncertainty". In due course, with the accumulation of practical experiences and inferences, some additional influencing factors and correlation among some variable parameters are identified. Incorporating all these additional factors and correlations, a new uncertainty budget with 13 variable parameters and factors is worked out and the measurement uncertainty of UIM is re-evaluated as Q(0.0092 Pa, 7.2 pp m of reading) at k=2 and the salient features of which are discussed in detail.

2 illus, 3 tables, 6 ref

024161   Sethuraman J U (NO, , 4/71 Kurinji Nagar, B Block, Reserve Line Madurai-625 014, Email: sethunirmal@yahoo.com ) : New approach to damped harmonic oscillator. Phys Educ 2006, 22(3), 177-82.

New approach is made in discussing the theory of damped harmonic oscillator (DHO) through convolution melhod known in Fourier transform technique. This approach serves as a good application to illustrate the use of convolution.

8 ref

024160   Randhawa R;Kaler R S (NO, Guru Jambeshwar Univ, Hisar, Email: rskaler@yahoo.com) : Further investigations for optical Kerr effects using split step fourier method for self phase modulation and dispersion. J Optics 2006, 35(3), 125-35.

Uses one of the most accurate method, the split-step numerical method (SSFM) to solve the Schrodinger wave equation and analyze dispersion and self phase modulation effects. SPM process produces new frequency components as the pulse propagates through the fiber. The new frequency components are positive and linear frequency chirp. In the anomalous regime chromatic dispersion produces negative frequency chirp and it tends to negate the positive chirp induced by SPM. Consequently, interacting between SPM and dispersion results in the reduction of the pulse broadening. On the other hand, in the normal dispersion region, chromatic dispersion also generates positive linear frequency chirp. Therefore, the effect of the pulse broadening is much more accelerated since the pulse has been spread out by both of SPM and dispersion.

3 illus, 10 ref

024159   Ramprasad A V;Uma Mageswari A;meenakshi M; Arumugam M (Electronics and Communications Engng & Phys Dep, Coll of Engng Anna Univ, Guindy - Chennai-600 015, Email: avramprasad2002@yahoo.co.in) : Study of four wave mixing nonlinear effect on various fiber types in DWDM optical systems. J Optics 2006, 35(3), 144-54.

Dense Wavelength Division Multiplexing (DWDM) transport systems are highly attractive in today's telecommunication scenario since they offer large capacity with a small number of channels and also achieve high spectrum efficiency. Fiber nonlinearities can have a serious impact on the performance of these systems. The presence of nonlinearities causes the channel capacity to be a nonmonotonic function of the input signal strength. The information throughput can be increased by using dispersion shifted fiber having minimum loss and zero dispersion at 1.55 μm wavelength and Er-doped optical fiber amplifiers in the fiber links. But low dispersion and high intensity of the signal launched enhance the four wave mixing, a third order nonªlinear effect. Due to this low dispersion and high intensity of light pulse, frequency mixing is made in an efficient manner and new wave length are generated. This is called four wave mixing penalty. If one of the generated new wave length is equal to signal wavelength in the DWDM modulated carrier, the interference or cross-talk is produced and that will reduce the signal to noise ratio at the receiver side. Describes inter modulation products which are generated due to four wave mixing effect and are observed experimentally using single mode fiber also Simulation is made with dispersion shifted fiber for two channel and sixteen channel wavelength division multiplexed transmission system. In addition, FWM power (cross-talk) is evaluated and compared for three major types of fibers like single mode fiber, dispersion shifted fiber, non-zero dispersion shifted fiber.

4 illus, 4 tables, 14 ref

024158   Ramasamy V;Rajkumar P;Ponnusamy V (Phys Dep, Annamalai Univ, Annamalai Nagar-608 002, Email: srsarnram@rediffmail.com) : Variation on luminescence effect of natural quartz extracted from Vellar river sediments. Bull pure appl Sci-Sect F 2006, 25(1-2), 25-9.

Describes an examination on the variation of luminescence effect of natural quartz grains extracted from sediments of Vellar river, Tamilnadu which is originating at Kalrayan hills and terminates the Bay of Bengal at Porto-Novo. The samples of all the twenty seven sites were tested for TL sensitivities. The luminescence intensity decreases when the river approaches the sea from the origin. The measurements of luminescence induced by gamma dose of 3.3 Gy were recorded. The TL dose responses alter irradiation have also been studied.

3 illus, 16 ref

024157   Ramasamy V;Ponnusamy V;Anandalakshmi K (Phys Dep, Annamalai univ, Annamalainagar-608 002, Email: srsaranram@rediffmail.com) : Thermoluminescence glow curve characteristics of natural well grown calcite. Bull pure appl Sci-Sect F 2006, 25(1-2), 7-12.

Thermoluminescence glow curve measurements were carried out for six calcite samples which were collected from Padaivedu mines of Tamilnadu. The TSL glow curves were recorded with three defferent treatments such as natural thermoluminescence, after gamma irradiation and gamma irradiation after thermally treated sample. The TSL glow curves obtained for each site samples shows similar trends with defferent treatment. The entire site sample shows similar structure in respect or shape and peak position but change in intensity.

6 illus, 6 ref

024156   Ramasamy V;Ponnusamy V;Ananalakshmi K (Physics Dep, Annamalai University, Annamalainagar-608 002, Email: srsaranram@rediffmail.com) : Determination of kinetic prameters through termoluminescence glow curve of well grown calcitic crystals. Bull pure appl Sci-Sect D 2006, 25(2), 67-73.

TSL glow curve were recorded with three different treatments i.e., natural, natural plus gamma irradiation induced curves and gamma irradiation after thermal treatment. The trapping parameters were calculated by using different experimental methods. By using partial heating method the number of peaks is identified. The preliminary evaluation of order of kinetics is also found. The obtained results show the sample follow the second order kinetics. All the peaks in the glow curve follow the same trend and they may correspond to monoenergetic traps.

4 illus, 2 tables, 8 ref

024155   Rajamannan B;Krishnan A (Phys Dep, Annamalia Univ, Annamalainagar-608 002, Email: rasikrishnan@gmail.com) : Physio-mechanical behaviour of clay-fly ash bricks at elevated temperatures. Bull pure appl Sci-Sect F 2006, 25(1-2), 19-23.

Physio-mechanical behaviour of different samples during firing has been studied. Brick samples were prepared using different composition of clay and fly ash and a range of firing temperatures (700-900°C). The bricks compositional characteristics were evaluated using stress and hydric tests. This information is important to elucidate technological achievements and raw material sources for civilizations and it can also be used to selected appropriate clay composition and firing temperatures for new bricks used in cultural heritage conservation interventions.

1 table, 10 ref

024154   Rajamannan B;Krishnan A (Physics Dep, Annamalai University, Annamalainagar-608 002, Email: rasikrishnan@gmail.com) : Ultrasonic velocity - porosity correlation for building bricks. Bull pure appl Sci-Sect D 2006, 25(2), 83-7.

As a rule the ultrasonic velocity of porous ceramic materials decreases with increasing porosity (Li, 2004; Mukhopadhyay and Phani 2000; Kreher 1977). For correlating the ultrasonic velocity with porosity, there exist several equations. On the basis of Austin (1939) an equation U = U_°0 ( ^{l - p}/_{l + np}) were formulated for ceramic materials., which correlates extremely well the ultrasonic velocity of the ceramic bodies with the porosity. Experimental data obtained for porous medium have been analyzed and compared with the theoretical results.

5 illus, 1 table, 5 ref

024153   Raghuwanshi S K;Pattnaik P K;Talabattula S; Rajappa P (Applied Photonics Lab, Electrical Communication Engng Dep, Indian Inst of Sci, Bangalore-560 012, Email: sanjeevkr@ece.iisc.ernet.in) : Analysis of pulse propagation through a nonlinear directional coupler. J Optics 2006, 35(3), 155-63.

Nonlinear directional coupler (NLDC) has aroused a lot of interest since it has been first proposed. A lot of proposals have been suggested for its as an optical signal processing unit. A successful application of NLDC as an optical processing unit would eliminate the electronic bottleneck that currently prohibits the data processing and transfer rates in optical networks. To our knowledge there is no treatise which deals with the pulse evolution equation in NLDC Describes in detail the functioning of NLDC by deriving the pulse evolution equations and analyzing their implications. Also provids a scheme to solve the equation numerically. Provided results of the simulations for some cases.

6 illus, 1 table, 11 ref

024152   Padhy B B;Chandrasekaran N;Joseph C S;Barui J K (Fiber Optics Lab., App Phys Dep, Defence Inst of Adv Technol, Girinagar, Pune-411 025, Email: bbpadhy2@yahoo.com) : Effects of varying source power on sensor performance in self-referenced fiber optic displacement sensor. J Optics 2006, 35(3), 136-43.

Reflective intensify modulated fiber optic displacement sensor with self-referencing method is studied and the effect of varying source power on the sensor response is investigated. The advantages and practical limitations of the rather simple referencing technique are experimented and reported. Calibration aspects of the sensor for different target materials are discussed. Also the effect of varying source power is experimented. The various issues on sensitivity and dynamic range are reported.

8 illus, 16 ref

024151   Nagib N N;Mahmoud N A;Omar M M;Ismail L Z (NO, National Inst for Standards, P.O. Box 136, Giza 12211, Egypt, Email: nabil_nagib@yahoo.com) : Accurate retardance and birefringence measurements of mica plates. J Optics 2006, 35(3), 164-70.

In recent works, it was shown that the retardances δ₁ and δ₂ of two birefringent phase plates C₁ and C₂ could be measured simultaneously at any wavelength by a single adjustment of the optical system. If the two plates are identical (δ₁ = δ₂ = δ), the calibration process becomes more simple, quick, accurate and the expressions for evaluating 8 are quite simple. Two mica plates of the same thickness d = (29.5±0.2) μm cleaved from the same crystal were calibrated in the spectral range 430-710 nm. In order to eliminate the alignment errors in the optical elements, four different arrangements of the system were employed. Results for retardance and birefringence values in the studies spectral range are presented.

3 illus, 13 ref

024150   Mukhopadhyay S;Ray K (NO, Institute of Physics, Bhubaneswar-751 005) : Branes in hearts with perverse sheaves. Indian J Phys 2006, 80(11), 1109-22.

Various topological properties of D-branes in the type-IIA theory are captured by the topologically twisted B-model, treating D-branes as objects in the bounded derived category of coherent sheaves on the compact part of the target space. The set of basic D-branes wrapped on the homology cycles of the compact space are taken to reside in the heart of t-structures of the derived category of coherent sheaves on the space at any point in the Kahler moduli space. The stability data entails specifying a t-structure along with a grade for sorting the branes. Considering an example of a degenerate Calabi-Yau space, obtained via geometric engineering, that retains but a projective curve as the sole non-compact part, authors identify the regions in the Kahler moduli space of the curve that pertain to the different t-structures of the bounded derived category of coherent sheaves on the curve corresponding to the different phases of the topological branes.

3 illus, 35 ref

024149   More A M;Lokhande C D (Thin Film Phys Lab, Phys Dep, Shivaji Univ, Kolhapur-416 004, Email: l_chandrakant@yahoo.com ) : Applications of TiO₂ in solar energy conversion. J Adv Sci Technol 2006, 9(1-2), 28-45.

Titanium dioxide is commercially very important as a white pigment because of its maximum light scattering with virtually no absorption and because it is nontoxic and chemically inert. It has been investigated extensively in the recent years because its utilization as low-cost material in photocatalysis, gas sensors and energy conversion devices. It is a high band gap semiconductor which holds much promise for photoelectrochemical applications related to solar energy conversion. Dye-sensitized TiO₂ solar cells with wide-band gap semiconductors offer an alternative method for the fabrication of low-cost solar cells. A monolayer of dye adsorbed onto porous TiO₂ surface is sufficient to collect a large part of solar spectrum. The major breakthrough in this direction is the use of dyed nano-porous TiO₂ films of very large effective surface area. Such films possess very high light absorption cross sections at the absorption wavelength of the dye, even at monolayer surface concentrations. This contribution presents a discussion on the applications of TiO₂ in solar energy conversion. The operational principle of dye sensitized TiO₂ solar cells and an overview of the recent results obtained for DSSS and SSDSSC are presented.

4 illus, 1 table, 89 ref

024148   Meenakshi G;Dixit A K;Gupta D K (Physics Dep, Kanchi Mamunivar Centre for Post Graduate Studies, Lawspet, Pondicherry-605 008) : Dielectric behavior of some polar molecules in benzene at microwave frequency: a remedy for pollution. Nat Envir Pollut Technol 2006, 5(3), 393-8.

Dielectric behavior of three polar liquids namely methyl acetate, methylene dichloride and 2-methoxy ethanol in nonpolar solvent benzene have been studied at microwave frequency 21.4 GHz at 300 K. Different dielectric parameters like static dielectric constant (ε_s ), dielectric constant (ε'), dielectric loss (ε∞) and optical dielectric constant (ε ) were determined. Using these parameters the various relaxation times viz., average relaxation time τ₍₀₎ molecular relaxation time τ₍₁₎ and group relaxation time τ₍₂₎ of the individual component have been calculated It has been observed that the relaxation time is closely related to the molecular parameters such as size, shape and nature of the solute molecule.

4 illus, 5 tables, 10 ref

024147   Lo C Y;Wong C (NO, Applied and Pure Reserch Institute, 17 Newcastle Drive, Nashua, NH 03060 USA) : Intrinsic difference between mass and electromagnetic energy and the repulsive effect in gravity. Bull pure appl Sci-Sect D 2006, 25(2), 109-17.

Currently, the formula E = mc² is often misinterpreted as the unconditional equivalence between inertial mass and each type of energy (i.e., m = E/c²). However. according to Einstein's general relativity, such a claim is incorrect. As Einstein clarified, the formula E = mc² must be understood in terms of energy conservation. Forinstance, the Reissner-Nordstrom metric illustrated that electromagnetic energy actually would produce repulsive gravity. Moreover, this non-equivalence is intrinsic in electromagnetism and is independent of the detailed calculations in general relativity. Experimental verification of such a repulsive gravity is proposed. Concurrently, it is pointed out that this is a major error in Will's book, "Theory and experiment in gravitational physics," that the Physical Review, Nature and Science considered as invaluable.

30 ref

024146   Lal T;Yadav S S (National Physical Laboratory, , Dr. K.S. Krishan Road, New Delhi-110 012, Email: tlal@nplindia.ernet.in) : Status of NPL, India in CCM. V-K1 intercomparison in viscosity. MAPAN 2006, 21(1), 47-59.

Describes in brief the first CCM key comparison in capillary viscometry in which eighteen National Metrology Institutes (NMIs) including National Physical Laboratory New Delhi (NPLI) have participated. This comparison was carried out between May and July 2002. Five Newtonian liquid with nominal kinematic viscosities of 10 mm²/s at 20°C, 1300 mm²/s at 20°C, 400 mm²/s at 40°C, 40 mm²/s at 100°C and 40000 mm²/s at 20°C were circulated to the participating laboratories. The measurement results of these participating laboratory were used to determine the degrees of equivalence between the individual NMIs and the key comparison reference value (KCR V). The final report of this intercomparison was published in 'Metrologia' in January 2004. The measurement results of NPLI and the degree of equivalence of its results with KCR V and other participated NMIs have been highlighted in details

4 illus, 3 tables, 15 ref

024145   Kawski A;Bojarski P (Mathematics Dep, Physics and Informatics Institute of Experimental Physics. Gdansk Uni, ul. Wita Stwosza 57, PL-80-952 Gdansk, Poland) : Photoselection of luminescent molecules in isotropic media and anisotropic media by multiphoton excitation. Electronic transition moment directions. Asian J Spectrosc 2007, 11(2), 67-79.

Theoretical and experimental results devoted to the problem of photoselection of luminescent molecules (LM) in isotropic and anisotropic media caused by one, two and three - photon excitation has been presented. The application of the theoretical considerations gives a possibility to determine the directions of electronic transition moments for prolate LM from absorption and emission measurements.

24 illus, 5 tables, 63 ref

024144   Joy Singh A;Pandit A K;Bhatt R J;Singh S K; Karimi N A (NO, S.K. Women's College, Nambol, Manipur, Email: na_karomi2000@yahoo.com) : Environmentally dependent electrical conduction of polyethylene terephthalate film at Patna (25 N, 85 E) - one of the humid tropical region on the Globe. Bull pure appl Sci-Sect D 2006, 25(2), 57-66.

Environmentally dependent electrical conductivity (σ) of polar polymer named polyethylene terephthalate film of thickness 250, 190, 125, 75. & 50 micron has been investigated as a function of electric field stress varied up to 2 x 10⁷ V/m in the humid tropical climate (RH% 60 to 95% and temperature 25±5° C). It has been observed that for thinner samples (σ) increases linearly with Relative humidity, but for higher thicknesses σ, reaches towards saturation. This has been explained on the basis of island structure theory. The thinner sample absorbs more & more water molecules with respect to thicker samples as the dimension of island is smaller in thinner samples than thicker. The I-V characteristics indicates that Poole-Frenkel (P-F) mechanism of conduction is operative for higher thicknesses of samples in low humid environment. Whereas Richardson Schottky (R-S) effect is dominant for thinner samples in high humid environment. The increasing trend of β, (P-F & R-S coeff.) with temperature is restricted or drops as soon as the transition temperature (Tg) is attained. It is also found that environmentally generated charge carriers play differently with respect to as thermally generated charge carriers in the conduction process. i.e. β increases with decrease of RH% whereas β also increases but with an increase of temperature of sample.

3 illus, 3 tables, 19 ref

024143   Jadhav S R;Pawar P H;Bhavsar G P (Phys Dep, Rasthtriya Coll Chalisgaon, Z.B. Patil Coll, Dhule) : Growth and synthesis of PbS thin films by thermal evaporation. J Adv Sci Technol 2006, 9(1-2), 82-90.

Polycrystalline PbS films have been deposited on to clean glass substrate at room temperature, by thermal evaporation technique. The structural, optical, electrical and compositional investigations on PbS thin films have been carried out. The optical band gap lies in the range of 0.6eV to 1.70eV, refractive indices and extinction coefficient are in the range 1.22 to 3 and 0.001 to 0.007 respectively. From the measurement of DC conductivity in the temperature rang 30, 0 to 378K, activation energy for charge transport have been evaluated and found in the range 0.11 to 0.20 eV. The composition of the film was analyzed using energy dispersive X-ray analysis (EDAX).

4 illus, 4 tables, 18 ref

024142   Gupta S (NO, Tata Inst of Fundamental Res, Homi Bhabha Road, Mumbai-400 005, Email: sgupta@theory.tifr.res.in) : Plasmas and dimensional analysis. Phys Educ 2006, 22(3), 149-55.

Plasma is any material which contains mobile charge carriers. Examines physics of plasmas using dimensional analysis to obtain two essential phenomena of plasma physics, namely, Debye screening and Landau damping. Shows how these phenomena carry over to relativistic quantum theories. Such relativisitic quantum plasmas are nowadays being studied in high energy physics labs.

1 table

024141   Dhanasekar B;Ramamoorthy B (Mechanical Engng Dep, Manufacturing Engng Section, Indian Institulute of Technol, Madras-600 036) : Evaluation of surface roughness using a image processing and machine vision system. MAPAN 2006, 21(1), 9-15.

With the advent of high-speed general-purpose computers and powerful high speed vision systems image analysis have become easier, faster and more flexible. Images of surfaces captured using vision system can be used to identify, analyse and quantify surface texture after the implementation of quality improvement algorithms. Unlike the stylus instruments, the computer vision systems have the advantages of being non-contact and are capable of measuring an area of the surface rather than a single line which makes it a 3D evaluation. Optical surface roughness parameter `Ga' has been obtained from an image and is compared with the widely used conventional average surface roughness 'Ra' obtained from the stylus instrument for ground, milled and shaped surfaces. Workpieces are made to varied roughness using varying manufacturing processes which include shaping, milling and grinding. The surface images are grabbed using a CCD camera (Pulnix TM-6) and then transferred to the PC workstation through a frame grabber. After preprocessing, geometric search technique is applied to enhance the quality of images. Then the optical surface roughness parameter Ga is calculated for all the captured surface images. These Ga values have been compared with the respective Ra values measured using a mechanical stylus instrument. It was observed that the optical surface roughness parameter Ga was in good correlation with the stylus Ra values after applying geometric search technique to improve the quality of the images. The complete analysis of results is presented in this work.

8 illus, 3 tables, 14 ref

024140   Desai D A;Pathare S R;Bapat M S (NO, , C-10 Patil Regency, Erandawana, Pune-411 004, Email: dattatraya.desai#gmail.com) : Bifilar pendulum. Phys Educ 2006, 22(3), 195-202.

This is an edited version of the experiment set for Indian National Physics Olympiad Examination - 2006, conducted at the Homi Bhabha Centre for Science Education (TIFR), Mumbai. In this experiment, studying the relations between the period of oscillation of the pendulum and various relevant parameters experimentally, students are to discover the correct formula using dimensional analysis. The oscillating body is in the form of a dumb-bell whose moment of inertia can be calculated from its geometrical dimensions and mass.

4 illus

024139   Demirci N (Necatibey Faculty of Education, Balikesir Univ, 10100 Balikesir/Turkey, Email: ndemirci@yahoo.com) : Using joke tales to impact physics instruction: an example using concepts in acoustics. Phys Educ 2006, 22(3), 183-9.

Discusses the potential role of Joke Tales to improve physics teaching andior learning. Wit, common sense, ingeniousness, ridicule and the kind of humor that reflects human psychology often indirectly helps the learning process. In this study the approach or assertion is incorporation of traditional instruction interspersed with well-known but humorous tales like Nasreddin Hodja 's of Turkey. to teach some science concepts (here in topics related to Sound).

17 ref

024138   Das S (Phys and Astronomy Dep, Univ of Kentucky, Lexington, KY 40506, USA) : Holograms of cosmological singularities. Indian J Phys 2006, 80(11), 1087-96.

Raychaudhuri's classic work led to the result that singularities are generic in General Relativity. Among them, space-like or null singularities are puzzling : they imply that "time" can have a beginning or end. Well known examples are singularities inside black holes and initial or final singularities in expanding or contracting universes. In recent times, String Theory is providing new perspectives of such singularities which may lead to an understanding of these in the standard framework of time evolution in quantum mechanics. Describe some of these approaches.

27 ref

024137   Chakrabarti S (NO, Maharaja Manidra Chandra Coll, 20, Ramkanto Bose Street, Kolkata-700 003) : Convenient method for measuring the refractive Indices and estimation of some microscopic parameters of a glass prism. Phys Educ 2006, 22(3), 167-75.

When the refractive index(RI) of a glass prism is measured for various spectral lines from a polychromatic source, the prism has to be placed at the minimum deviation position for each colour in the conventional method. A more convenient way is to place the prism at a suitable position once and for all and to measure the deviations of all, lines together with the angle of incidence. One can calculate the RIs with an accuracy comparable to that achieved by measuring the minimum deviation in the conventional method. With an accurate measurement of the Rls, one can estimate several interesting parameters of the glass prism including its molecular polarizability.

2 illus, 4 tables, 9 ref

024136   Banerjee N (Relativity and Cosmology Research Centre, Phys Dep, Jadavpur Univ, Kolkata-700 032) : Accelerated expansion of the universe and scalar tensor theory of gravity. Indian J Phys 2006, 80(11), 1097-1100.

Possible role of a scalar field, non minimally coupled to gravity, in the search for dark energy is very briefly reviewed. Some possibilities in the framework of Brans-Dicke theory are discussed.

14 ref

024135   Asokamani R;Manivasagam G (School of Mechanical and Building Sciences, Vellore Institute of Technology, Vellore-632 014, Email: asokamanir@yahoo.co.uk) : Ductility enhancement of TI based alloys - A theoretical approach. Metals Mater Process 2006, 18(3-4), 261-68.

In the absence of proper theoretical guidelines, hard core metallurgists, with all their earlier experience, have been trying hard with different alloying combinations for obtaining ordered Ti based intermetallics with improved ductility to be used for high temperature applications. In principle, ab initio theoretical calculations can be performed with different permutation and combination of alloying elements to look for alloys with required properties, which, of course have to take into account several other factors such as the phases present, their volumes, defects, microstructures etc. which will be a tremendously horrendous job. This necessitates one to look for certain guidelines out of the theoretical works performed so far. Electronic band structure calculations have been performed by the author and his group on a large number of binary, ternary and quaternary intermetallics. It has been found that the Fermi level invariably lies in the vicinity of what is termed as a pseudogap, a sharp valley in the density of states histogram. The main objective is to see whether macroscopic criteria for better ductility laid down by von Mises and Pugh can be given a microscopic or quantum mechanical interpretation.

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