019097   Singh T;Chaubey R (Applied Mathematics Dep, Inst of Technol, Banaras Hindu Univ, Varanasi-221 005, Email: drtriloksingh@yahoo.co.in) : Cossmic no-hair conjecture in scalar-tensor theories. Pramana J Phys 2006, 67(6), 1037-41.

Shows that, within the context of scalar-tensor theories, the anisotropic Bianchi-type cosmological models evolve towards de Sitter Universe. A similar result holds in the case of cosmology in Lyra manifold. Thus the analogue of cosmicno-hair theorem of Wald hold in both the cases. In fact, during inflation there is no difference between Scalar-tensor theories, Lyra's manifold and general relativity (GR).

23 ref

019096   Singh R K;Pandey K K (Physics Dep, Banaras Hindu Univ, Varanasi-211 055, Email: rksingh_17@rediffmail.com) : Ultrasonic behaviour of nanocrystallin Ni₃Fe(15 nm). Indian J Phys 2006, 80(10), 979-82.

Ultrasonic attenuation due to phonon-phonon interaction, thermoelastic loss and dislocation damping due to screw and edge dislocations have been evaluated in nanocrystalline Ni₃Fe (I5nm), for longitudinal and shear waves, along <60>100<62>, <60>110<62> and 111<62> crystallographic directions of propagation and for various polarization directions. It has been found that utrasonic behaviour of nanocrystalline face cenbled cubic resembles that of fee bulk phase alloys and it has been found that like metallic alloys, contribution to total attenuation due to thermoelastic loss is negligible in comparison to attenuation due to phonon-phonon interaction.

13 tables, 19 ref

019095   Singh N P;Singh A K;Arvind Kumar;Singh A K (NO, , 236, Durga Nagar, Firozabad-283 203) : Heat transfer flow of stratified viscous fluid past a porous vertical plate. Ultra Scient phys Sci 2006, 18(3M), 569-76.

Unsteady free convection flow of an incompressible, electrically conducting, viscous, stratified fluid through a porous medium past a vertical, porous, infinite plate with time dependent suction velocity in presence of transversely applied uniform magnetic field is studied. The plate is maintained at a constant temperature, which decays exponentially with time. Perturbation technique is annlied as suggested by Lighthill¹. Solutions for the fluid velocity and temperature field are obtained. The expressions for skin-friction coefficient and rate of heat transfer are also derived. The velocity field is discussed for different values of Prandtl number. Stratification factor, Grashof number, Hartmann number, heat source parameter and permeability parameter with the help of graphs. The temperature distribution for various values of Prandtl number and heat source parameter is also discussed. The effects of various parameters on skin-friction and rate of heat transfer are presented in tables numerically and discussed.

1 illus, 2 tables, 18 ref

019094   Singh N P;Singh A K;Arvind kumar;Singh A K (NO, , 236, Durga Nagar, Firozabd-283 203) : Heat and mass transfer flow of a viscous fluid past an infinite porous plate with time dependent suction and heat flux. Ultra Scient phys Sci 2006, 18(3M), 561-8.

Theoretical analysis of unsteady free convection flow of a viscous fluid past an infinite porous vertical plate in non-homogeneous porous medium taking time dependent suction velocity and constant heat source into account. The permeability of the porous medium and the suction velocity at the plate decreases exponentially with time. Approximate solutions are obtained for velocity and temperature fields. The expressions for skin-friction and rate of heat transfer are also derived. The effects of various physical parameters, encountered into the problem, on the velocity field and temperature field are numerically shown through graphs while the effects on skin-friction and rate of heat transfer are numerically discussed through tables.

2 illus, 2 tables, 18 ref

019093   Singh H;Singh H;Singh B;Bansal M L (Mathematics Dep, Statistics and physics, Punjab Agriultural Univ, Ludhiana) : Water sorption studies in different varieties of furniture wood. J Res 2006, 43(3), 198-203.

Water sorption studies have been carried out on four varieties of wood i.e. Tahli, Sagwan, Safeda and Champ. In Water sorption studies wetting- drying cycles as well as wetting processes have been studied upto fourth cycle in fore mentioned varieties. The wetting - drying cycles showed continuous decrease in hysteresis areas for Sagwan and Champ wood, whereas no significant change was observed in hysteresis areas for Tahli and Safeda wood. This consistency was also observed in wetting processes. The slopes for wetting process showed continuous decrease for Sagwan and Champ wood, while for Tahli and Safeda wood slopes were constant upto fourth cycle. The wetting processes were excellently represented by quadratic relations; with coefficients being significant at 1% level of significance. The R² value between fitted and observed data was in the range of 0.92 to 0.98 in respect of all the cases studied.

3 tables, 2 illus, 6 ref

019092   Siddiqui S U;Sapna Km (Mathematics Dep, Harcourt Butler Technological Institute, Kanpur-208 002, Email: susiddmath@yahoo.com) : Herschel-Bulkley fluid model for blood flow through a stenosed artery. Ultra Scient phys Sci 2006, 18(3M), 407-16.

Model is presented to study the influence of shape parameter (m) on resistance to flow (λ) and apparent viscosity (μ₀/μ) on blood flow through stenosed artery. Blood is modeled as Herschel-Bulkley fluid in a uniform circular tube with an axially non-symmetric but radially symmetric stenosis. The expressions for dimensionless resistance to flow and apparent viscosity have been obtained. The variation of resistance to flow (λ) and apparent viscosity (μ₀/μ) with shape parameter (m), shear stress (τ₀), stenosis length (L₀/L), and stenosis size (δ/R₀) has been shown graphically. It has been found that the resistance to flow decreases as shape parameter increases as well as stenosis size increases. It has also been observed that resistance to flow increases as stenosis length increases and decreasing as stenosis shape parameter increases. The apparent viscosity decreases as stenosis shape parameter increases and stenosis size increases respectively. It has been shown that apparent viscosity increases as yield stress increases and decreases as stenosis shape parameter increases. Further, we have seen the effect of yield stress on resistance to flow and stenosis length on stenosis shape parameter. The significance of the present model over the existing models has been pointed out by comparing the results with other theories both analytically and numerically.

ref

019091   Sharma P R;Agarwal B (Mathematics Dep, Rajasthan Univ, Jaipur-302 004) : Pulsatile MHD flow and heat transfer between parallel porous plates with ohmic dissipation and heat source. Ultra Scient phys Sci 2006, 18(3M), 445-58.

Investigates pulsatile flow of a viscous incompressible electrically conducting fluid and heat transfer through parallel porous non-conducting plates in the presence of pulsatile pressure gradient Ohmic dissipation, heat source and transverse magnetic field. The fluid is injected through the lower plate at a constant rate and sucked at the same rate through the upper plate. The plates are maintained at uniform temperatures. The governing equations of motion and energy are solved by the variable separable and regular perturbation techniques. The velocity and temperature distributions are derived, discussed numerically and shown through graphs. The expressions of skin-friction coefficient and the Nusselt number at the plates are derived, discussed numerically and their numerical values for various values of physical parameters are presented through Tables.

8 illus, 2 tables, 14 ref

019090   Sharma D;Sharma G S;Verma A S;Bhardwaj (S R Physics Dep, B.S.A. College, Mathura-281 004) : Structural properties of (IVB) zirconium trichalcogenides. Acta Cienc Indica-Phys 2006, 32(2), 193-5.

Investigates the structural properties such as homopolar gap (E_h), ionic gap (E_c), average energy gap (E_g) and crystal ionicity (f_i) of Zirconium trichalcogenides using the Phillips and Van Vechten (PVV) theory. A linear relationship between the values of electro negativity differences and crystal ionicity has also been discussed.

1 illus, 2 table, 5 ref

019089   Sengupta Mitra M;Sarkar P K (Health Physics Unit (ARSS, RSSD, BARC), Variable Energy Cyclotron Cent, , 1/AF Bidhan Nagar, Kolkata-700 064, Email: pks@veccax.ernet.in) : Energy deposition in NaI(TI) and BGO detectors by hig-energy gammas and Monte Carlo estimation of absorbed dose in a human phantom. Indian J Phys 2006, 80(10), 1033-6.

To address radiological problems in electron accelerators, Monte Carlo simulations have been carried out to estimate the actual energy deposition in (5cm φ x 5cm) Nal and BGO detectors and a (3Ocm φ x l40cm) cylindrical tissue equivalent phantom by high-energy (up to 100 MeV) gammas. Bremsstrahlung gammas of such energies produced in high-energy electron accelerators make radiation dose measurement difficult due to unknown detector responses and complex energy deposition process. The simulation studies give an estimate of the energy deposited in the detectors and correlate the same with that in the phantom helping determination of personnel absorbed dose.

4 illus, 1 table, 6 ref

019088   Sen Gupta S (Theoretical Phys Dep, Indian Association for the Cultivation of Sci, Jadavpur, Kokata-700 032, Email: tpssg@iacs.res.in) : Observable consequences of gauge inariant electromagnetic-torsion coupling - a departure from Ensteinian gravity. Indian J Phys 2006, 80(11), 1135-45.

Presence of a gauge invariant coupling of electromagnetic field with space time torsion in a string inspired effective field theory is discussed. Departure from the estimates of classical tests of General Relativity is predicted because of such a coupling. It is further shown that the observed optical rotation of the plane of polarization of distant galactic radiation in excess of the Faraday rotation can be explained in such a scenario.

26 ref

019087   Selvanayagam S;Velmurugan D;Yamane T;Suzuki A (Crystallography and Biophysics Dep, University Madras, Guindy Campus, Chennai-600 025, Email: d_velu@yahoo.com) : PHENIK, a high throughput structure determination tool for single-wavelength anomalous diffraction data. Indian J Phys 2006, 80(10), 969-74.

In Structural Genomics, one is interested in determining the structure in the fastest way to understand new folds and this has opened up the "High Throughput Crystallography". This High Throughput structure determination requires automation to reduce the obstacles related to human intervention. PHENIX is a new software package for the automation of crystallographic structure solution of macromolecules. The algorithms in PHENIX allows one to proceed from reduced intensity data to a refined molecular model and to facilitate structure solution for both the expert and non-expert crystallographers. In cases where PHENIX builds an incomplete model of less residues with or without side chains. ARP/wARP can be made use of to proceed further with this as input. Attempts are here made in extending the use of PHENIX for the high throughput structure elucidation of glucose isomerase of approximately 44 kDa molecular weight with lab source CuKa and CrKa anomalous scattering data sets corresponding to 1.7 and 2.3 A resolutions. respectively. One manganese position initially located by PHENIX is enough to build the entire structure using the CuKa data whereas additional heavy atoms (II heavy atoms) arc required in case of CrKa data to build the entire structure.

4 illus, 3 tables, 14 ref

019086   Saxena P K;Saxena S (Physics Dep, Bareilly College, Bareilly (UP)) : Anisotropy in electron-hydrogen and electron helium collision. Acta Cienc Indica-Phys 2006, 32(2), 177-83.

Excitation of 2s-3s state of H and 1¹s-2¹s state of He atom by electron and positron is studied using two potential approach. The calculation for asymmetry parameter A and ratio are performed at energy 100 eV. The computed results are compared with available results. Due to lack of experimental data we are unable to explain the co-relation between experimental and present theory.

4 illus, 11 ref

019085   Sanjid a M;Chaudhary K P;Singhal R P (National Physical Laboratory, , New Delhi-110 012, Email: sanjid@mail.nplindia.ernet.in) : Calibration of gauge blocks using automatic phase stepping interferometer at NPLI with Nanometer uncertainty. MAPAN 2006, 21(2), 103-9.

The only difference between nanotechnology and many other fields of science or engineering is that of size. Control in manufacturing at the nanometer scale still requires accurate and traceable measurenrent at Nano-scale. The Automatic phase stepping gauge block interferometer (Model: GBI-300) is installed in cabin where environmental conditions are well maintained. The controlled parameters are (1) temªperature (20:1: 0.5C), (2) humidity (50:1: 10), (3) vibration level (0. 3pm amplitude@ 10 Hz) and (4) dust level (10,000) class respectively. Under these onnrentalconditions, one can measure gauge blocks of length up to 300 mm with an associated uncertainhj around 80 nm. NPL-India provides traceability in length measurement to the industry in India and neighboring countries like Nepal, Saudi Arabia and Sri Lanka. The procedure, results are compared globally by in ternaª

4 illus, 3 tables, 8 ref

019084   Ray A K;Bhattacharjee J K (NO, Inter-Univ Centre for Astronomy and Astrophys, Post Bag 4, Ganeshkhind, Pune-441 007, Email: akr@iucaa.ermet.in) : Static and dynamic aspects of transonicity in bondi accretion. Indian J Phys 2006, 80(11), 1123-4.

Transonicity in a spherically symmetric accreting system has been considered in both the stationary and the dynamic regimes. The stationary flow, set up as a dynamical system, has been shown to be greatly unstable to even the minutest possible deviation in the boundary condition for transonicity. "With the help of a simple analytical model, and some numerical modelling, it has then been argued that the flow indeed becomes transonic and stable, when the evolution of the flow is followed through time. The timeª dependent approach also shows that there is a remarkable closeness between an equation of motion for a perturbation in the flow, and the metric of an analog acoustic black hole.

7 illus, 19 ref

019083   Rathod V P;Tanveer S (Studies and Research in Mathematics Dep, Gulbarga Univ, Gulbarga-585 106) : Pulsatile flow of blood with periodic body acceleration and magnetic field through an exponentially diverging vessel. Ultra Scient phys Sci 2006, 18(3M), 417-26.

Pulsatile flow of blood through vessels of exponential divergence under the influence of periodic body acceleration and magnetic field by considering blood as a couple stress fluid. With the help of Laplace and finite Hankel transforms, analytical expressions for axial velocity, flow rate and fluid acceleration has been obtained. The solutions for velocities are compared with small increasing rates of vessel divergence. It is of interest to note that as the magnetic effect is increased the velocity of the blood decreased. Thus, by deaccelerating the velocity certain cardiovascular diseases can be treated by the magnetic effect. The effects of magnetic field and body acceleration have been discussed.

5 illus, 27 ref

019082   Pujar S S;Bhati S M (Mathematics Dep, SRES College of Engineering, Kopargaon-423 603, Email: satishbhati@rediffmail.com) : On Riemannian manifolds admitting a nonhomothetic infinitesinmal conformal tramsformation group. Ultra Scient phys Sci 2006, 18(3M), 459-70.

N-dimensional (n <62> 2) compact and orientable Riemannian manifold M admitting a conformal transformation X in M satisfying (2.1) is the main purpose. Obtaines the integral formulas in Riemannian manifold and use them as powerful tool to describe the global results has been considered. Some conditions in terms of integral formula for M to be isometric to a sphere without putting restrictions on the scalar curvature of M has been obtained. Finally generalises some of the results of earlier authors and some of those of S.S. Pujar and S.M. Bhati.

35 ref

019081   Pawan Kumar;Singh T P;Vipin Kumar;Virendra Singh;Gulbir Singh;Arvind Kumar;Pravesh Kumar (Physics Dep, J.V. College, Baraut, Baghpat) : Determination of size of CdS particles by theoretical approach using optical absorption. Acta Cienc Indica-Phys 2006, 32(2), 229-33.

The nano particles of cadmium sulphide have been prepared successfully in methanolic solution of cadmium nitrate by the controlled reaction of Na₂S. The solution was subjected for optical absorption spectra. The UV/Visible spectra have been obtained in the range 500 nm to 250 nm. In this paper we report that in the methanol the probability of formation of nano particles is equal everywhere and methanol works as a homogeneous medium. The average particle size have found to be 7 nm approximately using the Wang and Mahlar empirical relations and compared with our earlier result.

3 illus, 13 ref

019080   Pathania Y;Ahluwalia P K (Phys Dep, Himachal Pradesh Univ, Shimla-171 005, Email: yogyatapathania@yahoo.com) : Vapour-liquid equilibria of the two- and three-dimensional monoatomic classical fluids interacting via double yukawa potential. Pramana J Phys 2006, 67(6), 1141-54.

Carried out Monte Carlo simulations in Gibbs ensemble for two-and three-dimenisional double Yukawa fluid. Compares liquid-vapour equilibrium curve with that of Lennard-Jones, when parameters occurrin double Yukawa potential are chosen to fit Lennard-Jones potential. The results are in good agreement. The role of repulsive and attractive contributions for the potential on the liquid-vapour coexistence region as well as on critical temperature and critical density has been studied. The critical temperature is found to be more sensitive than the critical density to the variation in repulsive and attractive parts of the potential. Also, the range of the attractive interaction directly influences range of the liquid-vapour coexistence region. It has been found that smaller the values of the_attractive parameter, larger is the coexistence region.

13 illus, 4 tables, 19 ref

019079   Padte N J;Ramakrishnan N (NO, Indian Institute of Technology Bombay, Mumbai-400 076, Email: ramkrish@me.iitb.ac.in) : Development of a fast image processing algorithm for auto-focusing of an image in contact-less measurement. MAPAN 2006, 21(2), 87-90.

Now a days, vision system is a major part of contact-less metrology. Many smart algorithms have been developed to improve quality of measurement. There is all evidence that the accuracy of measurement in vision system is mainly dependant on sharp focusing and proper illumination. Precise focusing being a major part, this paper gives an idea of a new fast method of all to focusing to improve the accuracy as well as repeatability of the measurement. Tire algorithm of auto focusing mainly measures density differences between adjacent and near-adjacent pixels along the scanning lines. After doing statistical analysis, it generates a unique number for focused images. This can be used to control the motion of tire servomotor to adjust tire position of digital camera.

6 illus, 4 ref

019078   Necklawy M;Bahrawy M;Hassan A;Farid N; Arifsanjid M (National Pysical Laboratory, , New Delhi-110 012, Email: sanjid@mail.nplindia.ernet.in) : Digital processing of speckle interferometry to measure film thickness and surface deformations. MAPAN 2006, 21(2), 81-6.

The thickness of an evaporated thin film is measured by digital processing of speckle patterns resulted from the speckle interferometry (51) and observed by 11 CCD camera to study tile phase information carried by the speckle patters on the surfaces of the thin film and the substrate. The resultant thickness value is compared with the value obtained from the Coating Unit Machine during tire procedure of evaporation, and the accuracy of measurement is discussed. The deformation of tile thin film surface is studied by applying one dimensional fast fourier transform (1 D-FFT) method with unwrapping phases. Three-dimensional plot of the surface deformation is presented.

6 illus, 1 table, 20 ref

019077   Narasimha Murthy V N;Kokila M K;Puttaraja; Shivashankar;Kulkarni M V;Shivaprakash N C (Phys Dep, Bangalore Univ, Bangalore-560 056, Email: shiv@isu.iisc.ernet.in) : Crystal structure of N-methyl-2-(p-octyl phenoxy) benzimidazole. Indian J Phys 2006, 80(10), 1025-7.

Crystal structure of N-methyl -2(p-octyl phenoxy) benzimidazole has been determined by X-ray methods. The compound crystallizes in monoclinic system, space group P2₁/c, with cell parameters a = 11.6479(2)Angstrom, b = 13.4292( 1 )Angstrom, c = 12.5994(9)Angstrom and β = 8.344(8)⁰. The benzimidazole ring is planar and makes a dihedral angle of 127.48(1)° with the aryloxy ring and is coplanar with N-CH) group. The two molecules are joined together by Van der Waals and weak inter molecular C-H...N interactions.

2 illus, 3 tables, 16 ref

019076   Nadgaran H;Sabaian M (Phys Dep, Coll of Sci, Shiraz Univ, Shiraz-71454, Iran, Email: nadgaran@susc.ac.ir) : Pulsed pump: thermal effects in solid state lasers under super-gaussian pulses. Pramana J Phys 2006, 67(6), 1119-28.

Solid state laser (SSL) powers can be realistically scaled when pumped by a real, efficient and multimode pulse. A fourth-order super-Gaussian pulse was assumed as a pump for SSL's and a complete analytical expression for the thermal phase shift is given. Moreover, the focal length of thermal lens in paraxial ray approximation regime was studied. The results when applied to a Ti : sapphire crystal show an appreciable correction for abberation compared to a top-hat pulse.

5 illus, 15 ref

019075   Mukhopadhyay S;Ray K (Theoretical Pshysics Dep, Indian Association for the Cultivation of Science, Calcutta-700 032, Email: Koushik@iacs.res.in) : 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, 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

019074   Mistry M;Kumar P (Physics Dep, College of Commerce, Patna) : Three body study of <. Acta Cienc Indica-Phys 2006, 32(2), 209-14.

Ground state of ²⁴Mg nucleus is investigated in a three body α - α - ¹⁶O model using two body potential of Gaussian shape. The hyper spherical harmonics method which reduces the three body Schrodinger eqn. to one dimensional integral equation in hyper radius (ρ) which has been solved for lower values of grand orbital quantum number K. We fing that H.H. contributes 80% of the binding energy in conformity with experience of tritone calcula-tion with hyper spherical harmonics. The next harmonics K = 2 contribution is only 10%. Expect conversed result for lower k = 4 harmonics, the calculation is in progress.

2 table, 26 ref

019073   Mandal G (NO, Tata Institute of Fundamental Res, Homi Bhabha Road, Mumbai-400 005, Email: mandal@theory.tifr.res.in) : Quantization of gravitons, gravity and sound waves. Indian J Phys 2006, 80(11), 1075-85.

Discusses some recent develoments in quantization of asymptotically AdS₅ x S⁵ geometries, with special emphasis on configurations preserving ≥ 4 supersymmetries. It has been shown that the spectrum on the boundary theory is reproduced by quantization of giant gravitons in AdS. Discusses a novel bosonization which plays an important role in this equivalence. By a simple generalization of this technique, arrived at an exact solution of Tomonaga's problem dating back to 1950, which is that of bosonization of fermions in a one-dimensional metal.

1 illus, 38 ref

019072   Kumar S;Singh S K;Singh S P;Yadav S K;Mishra R K;Singh A K;Mishra L K (Physics Dep, Magadh Univ, Bodh-Gaya-824 234) : Ortho to para conversion in solid tritium and evaluation of two phonon process η(2) as a function of debye temperature and two phonon intrinsic rate r as a funcition of temperature. Acta Cienc Indica-Phys 2006, 32(2), 153-62.

Evaluate numerically the two phonon process η⁽²⁾ as a Junction of Debye temperature θ_D and η⁽²⁾ as a Junction of temperature T with fixed θ_D for ortho to para conversion in solid tritium using Berlinsky and Hardy formalism. The evaluated results are in good agreement with the experimental data.

3 table, 25 ref

019071   Kar S K;Datta T;Bhattacharya A B;Das R (Phys Dep, Univ Of Kalyabu, Kalyani-741 235, Email: physics@klguniv.ernet.in) : Statistical approach on measuring atmospheric noise ad lightning activity at two stations of same latitudinal belt. Indian J Phys 2006, 80(10), 1017-19.

Data of atmospheric noise at Kalyani in India originated from lightning as electromagnetic radiation and cloud-to-ground lightning occurrences measured in Taiwan, both under the same latitude belt, have been considered to investigate the characteristics of the lightning phenomena. The seasonal variations of atmospheric radio noise field strength against thunderstorm occurrences for both daytime and nighttime exhibit a close similarity in the trend for east, central and north zones in India. A comparison of monthly variations of +ve, -ve and total CG strokes for different months over Taiwan reveals that the negative strokes are primarily responsible for producing a particular characteristic variation over a zone. Finally, the scopes of future work on source activity are focused.

5 illus, 6 ref

019070   Kalra Y;Sinha R K (TIFAC-Center of Relevance & Excellence in Fiber Optics & Optical Commu, Delhi Coll of Engng, Faculty of Technol (Univ of Delhi), Bawana Road, New Delhi-110 042, Email: yogita25@rediffmail.com) : Photonic band gap engineering in 2D photonic crystals. Pramana J Phys 2006, 67(6), 1155-64.

Polarization-dependent Photonic band gaps (TM and TE polarizations) in two-dimensional photonic crystals with square lattices composed of air holes in dielectric and vice versa i.e., dielectric rods in air, using the plane-wave expansion method are investigated. Studied how the photonic band gap size is affected by the changing ellipticity of the tonstituent air holes/dielectric rods. It is observed that the size of the photonic band gap changes with changing ellipticity of the constituent air holes/dielectric rods. Further, it is reported, how the photonic band gap size is affected by the change in the orientation of the constituent elliptical air holes/dielectric rods in 2D photonic crystals.

8 illus, 11 ref

019069   Kakde K P;Shirale D J;Kharat H J;Gaikwad P D; Savale P A;Gade V K;Hussaini S S;Dhumane N R;Shirsat M D (Physics Dep, Dr. Babasaheb Ambedkar Marathwada Univ, Sensor Research Laboratory, Aurangabad-431 004) : Analysis of modified cladding step index multimode fiber optic evanescent wave chemical sensor. J Instrum Soc India 2006, 36(3), 220-26.

Theoretical analysis of a modified film step-index multimode fiber optic-evanescent wave chemical sensor which can be used for detection of vapour has been carried out. The numerical treatment is based on the ray theory of light. In present work, authors used multimode optical fiber. Optimized the evanescent field for the development of chemical sensor. Various sensor parameters like critical angle, refractive index of core, and refractive index of cladding of optical fiber for maximum evanescent power has been optimized.

4 illus, 16 ref

019068   Jain S K;Jain A;Sharma D;Hannurkar P R (Raja Ramanna Centre for Advanced Technology, , Indore-452 013, Email: skjain@cat.ernet.in) : Acquisition and analysis of langmuir probe chanracterization for ECR plasma. Indian J Phys 2006, 80(10), 1011-15.

An Electron Cyclotron Resonance (ECR) plasma source at 2450 MHz, 2 kW have been designed and developed. Plasma chamber was excited with 350 walls of microwave power with nitrogen gas and power was coupled to the plasma chamber through ridged waveguide. Plasma density and electron temperature were studied under various operating conditions like magnetic field, gas pressure and microwave power. Langmuir probe is used for plasma characterization using current-voltage (I-V) characteristics ion saturation method. The nitrogen plasma density of approximately 4.5x 10¹¹ cm^-3) and electron temperature of cold: 3-10 eV, hot: 45-85 eV are obtained. Presents very simple techniques for measuring I-V characteristics of medium density in the order of 10¹¹ to 10¹² cm^-3) and plasma temperature of cold: 1-10 eV, hot: 25-100 eV. The scheme comprises of a very simple resistive circuit that gives signals proportional to current and voltage across the probe. These signals are then applied to the PC based data acquisition hardware through buffers. The scheme simply recorded data acquired from the plasma and then processed the data offline to generate various results. The program is developed in Lab-View, so that it can be applied to any platform using common laboratory instruments.

7 illus, 20 ref

019067   Jafarizadeh M A;Foroutan M;Ahadpour S (Theoretical Phys and Astrophys Dep, Tabriz Univ, Tabriz 51664, Iran, Email: jafarizadeh@tabrizu.ac.ir) : Hierarchy of rational ordder families of chaotic maps with an invariant measure. Pramana J Phys 2006, 67(6), 1073-86.

Introduces an interesting hierarchy of rational order chaotic maps that possess an invariant measure contrast to the previously introduced hierarchy of chaotic maps, with merely entropy production, the rational order chaotic maps can simultaneously produce and consume entropy. Computes the Kolmogorov-Sinai entropy of these maps analytically and also their Lyapunov exponent numerically, where the obtained numerical results support the analytical calculations.

1 illus, 19 ref

019066   Hossain M;Mukherjee S;Mukherjee S (M.S, High Madrasah, Malda-732 206) : Unsteady MHD free convective flow and mass transfer in a rotating porous medium. Acta Cienc Indica-Phys 2006, 32(2), 235-44.

An analysis of unsteady two-dimensional free convective flow with mass transfer of an electri-cally conducting fluid past a vertical porous plate in presence of a transverse magnetic field a rotating porous medium is considered. The vertical porous plate is subjected to uniform instant suction perpendicular to the plate and temperature at this surface fluctuates in time out non zero constant mean solution of the equations governing the flow are obtained with help of power series. Conclude with a discussion of the results obtained.

4 illus, 8 ref

019065   Gupta N;Deb B M (Theoretical Chem Group, Chem Dep, Panjab Univ, Chandigarh-160 014, Email: bmdeb@yahoo.co.in) : Does the classically chaotic Henon-Heiles oscillator exhibit quantum chaos under intense laser fields. Pramana J Phys 2006, 67(6), 1055-71.

Quantum dynamics of an electron moving under the Henon-Heiles (HH) potential in the presence of external time-dependent (TD) laser fields of varying intensities have been studied by evolving in real time the unperturbed ground-state wave function ψ(x, y, t) of the HH oscillator. The TD Schrodinger equation is solved numerically and the system is allowed to generate its own wave packet. Two kinds of sensitivities, namely, senªsitivity to the initial quantum state and to the Hamiltonian, are examined. The threshold intensity of the laser field for an electron moving in the HH potential to reach its continuum is identified and in this region quantum chaos has been diagnosed through a combination of various dynamical signatures such as the autocorrelation function, quantum 'phase-space' volume, 'phase-space' trajectory, distance function and overlap integral '(akin to quantum fidelity or Loschmidt echo), in terms of the sensitivity towards an initial state characterªized by a mixture of quantum states (wave packet) brought about by small changes in the Hamiltonian, rather than a 'pure' quantum state (a single eigenstate). The similarity between the HH potential and atoms/molecules in intense laser fields is also analyzed.

9 illus, 39 ref

019064   Gupta J K;Sharma R (National Physical Laboratory, , New Delhi-110 012, Email: jkgupta@mail.nplindia.ernet.in) : Digital PRT : a case study for uncertainty estimation. MAPAN 2006, 21(2), 111-18.

Industrial Platinum Resistance Thermometers are widely being used for the measurement of temperature. In Industry and as working standards in Calibration Laboratories, in the range -200° C to 650°C. The IPRTs are calibrated in Liquid Baths or Block Calibrators by comparison method against Standard Platinum Resistance Thermometers. In this paper, the evaluation of uitcertainty of measureªment in the calibration of Digital Thermometer with IPRT probe has been discussed. A detailed analysis of contributions from various factors to the uncertainty in measurement associated with the calibration results has been given. The expanded uncertainty of digital thermometer with IPR T probe at a temperature of 300 DC has been estimated as ± 106 m°C (±0.106°C) at approximately 95% confidence level with coverage factor 'k' = 2 for nOnJlal distribution.

1 illus, 4 tables, 9 ref

019063   Gopakumar R (NO, Harish-Chandra Research Institute, Chhatnag Road, Jhusi, Allahabad-211 019, Email: gopakumr@mri.ernet.in) : Holography and hydrodynamics. Indian J Phys 2006, 80(11), 1071-3.

Describes some recent insights from string theory into & holography especially in the context of a hydrodynamic description of black hole physics.

10 ref

019062   Gogoi P;Konwar K;Baishya B (Phys Dep, Dibrugarh Univ, Dibrugarh-786 004, Email: Paragjyoti_g@rediffmail.com) : Study of ge-thin film transistors with rare earth oxiddes as gate insultors. Indian J Phys 2006, 80(10), 1021-3.

Polycrystalline Ge- thin film transistors having 50 μm channel length with rare earth oxides (Nd₂O₃, Dy₂O₃ and Eu₂O₃ and La₂O₃) as dielectric layers, have been studied. Various transistor parameters of the devices such as output resistance (r_d). transconductance (g_m). amplification factor (μ) and gain bandwidth product (G.Bw) are measured from the I-V characteristics. Some other important thin film transistors (TFT) parameters such as trap density (N₁), critical donor density (N_d^*). crystallite size (L) and mobility (μ_b) are measured using the theoretical model proposed by Levinson et al.

4 illus, 2 tables, 15 ref

019061   Goel S;Bansal V;Rajendra Kumar (Department of P.G. Studies and Research in Physics, J V Jain College, Saharanpur) : Damping effect on axisymmetric vibrations of an orthotropic circular plate of parabolically varying thickness with temperature variations. Acta Cienc Indica-Phys 2006, 32(2), 185-91.

The effect of Damping and constant thermal gradient on free vibrations of an orthotropic elastic circular plate of Parabolically varying thickness has been analysed in present research work. The governing differential equation of motion has been solved by Frobenius method. The sequencies corresponding to the first two modes of vibrations have been obtained for an orthotropic circular plate with different combinations of boundary conditions for various values of damping constant, taper constant and temperature gradient.

11 ref

019060   Ghosh D;Dev A;Sarkar S;Haldar P K (Nuclear and Particle Physics Research Centre, Phys Dep, Jadavpur Univ, Kolkata-700 032) : Dynamical azimuthal fluctuation of target fragments in forward and backward hemisphers in case of <. Indian J Phys 2006, 80(10), 1029-32.

Reports the analysis of the data of target fragments in both forward and backward hemispheres in case of ³²S - AgBr interactions at 200XGeV. Reveals the existence of emission asymmetry in the azimuthal plane which is found to depend on the number of target fragments.

3 illus, 2 tables, 28 ref

019059   Fakir Chand;Mishra S C (Phys Dep, Kurukshetra Univ, Kurukshetra-136 119, Email: fchand_kuk@yahoomail.com) : Construction of exact complex dynamical invariant of a two-dimensional classical system. Pramana J Phys 2006, 67(6), 999-1009.

Presents the construction of exact complex dynamical invariant of a two dimensional classical dynamical system on an extended complex space utilizing Lie alge-braic approach. These invariants are expected to play a vital role in understanding the complex trajectories of both classical and quantum systems.

19 ref

019058   Dwivedi A P;Siddiqi T (Applied Sciences Dep, Anand Engineering College, Agra) : Stress intensity factors for three collinear Griffith cracks located symmetrically in a stress-free elastic strip and opened by a symmetrical system of body forces. Ultra Scient phys Sci 2006, 18(3M), 427-32.

Obtains the solution for the problem of determining the stress intensity factors for three Collinear Griffith cracks located symmetrically in a stress -free elastic strip and opened by a symmetrical system of body forces, by reducing it to Fredholm integral equations of the second kind. The solution of these integral equations is given by expanding the unknown function in terms of d^-1 (d being half of the width of the strip). Numerical results for physical quantities like crack shape, normal component of stress at y=0 are also included and finally the partial closure of the crack is considered.

7 ref

019057   Dutta S;Dastidar K R (Spectroscopy Dep, Indian Ass for the Cultiv of Sci, Kolkata-700 032, Email: sulagna_dutta@yahoo.co.in) : Control of amplification without inversion in H₂ and LiH molecules: dependence on relative magnitude of probe and coherent field Rabi frequencies in three-level Λ system. Pramana J Phys 2006, 67(6), 1099-1118.

Dependence of amplification without inversion (AWI) on the relative strength of probe and coherent field Rabi frequencies has been studied in H₂ and LiH molecules for three-level Ω configuration. Derived exact analytical expressions for coherences and populations keeping all the orders of probe field Rabi frequency (G) and coherent field Rabi frequency (Ω) in the steady state limit. Previously, first-order approximation (i.e. keeping only the first-order term in G) was used and hence AWI was studied for the condition Ω <62><62>G. Here, by using the exact analytical expressions of coherences and populations, it has been shown that AWI is maximum when Ω is within the same order of probe field Rabi frequency G irrespective of the choice of different ro-vibrational transitions in both the molecules. However, the shape of the gain profile and the maximum value of gain on the probe field and the absorption on coherent field depend on the choice of different ro-vibrational levels as the upper lasing levels. Effect of bidirectional pumping, homogeneous and inhomogeneous broadening on AWI process has been studied. By solving the density matrix equations numerically it has been shown that both the transient and the steady state AWI can be obtained and the numerical values of coherences and populations at large time are in very good agreement with exact analytical values in the steady state limit. It has been shown that in molecules AWI can be obtained on probe field of smaller wavelength than that of the coherent field which has not been observed in atoms so far.

6 illus, 4 tables, 33 ref

019056   Dudul S V;Ghatol A A (Applied Electronics Dep, Faculty of Engineering and Technology, Amravati Univ, Amravati) : Identification of a typical hydraulic actuator system using a neural network based ARX model. J Instrum Soc India 2006, 36(3), 159-67.

The paper investigates the identification of a typical hydraulic actuator system using a model based on two-layer multi-layer perception neural network. It is shown that the neural based ARX model clearly outperforms the possible linear models in simulation and correlation characteristics of the prediction error and thus, it is possible to obtain reasonable results for the hydraulic actuator system with neural network based ARX model. As correlation functions of the prediction errors tend to remain confined more closely to the specified confidence regions, it is likely that most of the information has been extracted from.the training set. It is by no means claimed that the "optimal" solution is found, however, it is shown that the proposed neural network based ARX model has provided a simple means for solving a challenging nonlinear problem, such as the one considered in this paper.

3 illus, 2 tables, 10 ref

019055   Dubey G S;Srivastava V P (Physics Dep, GS P.G. College Samodhpur, Jaunpur, ) : Explicit magnetofluid solutions of einstein field equations. Acta Cienc Indica-Phys 2006, 32(2), 173-6.

General class of inhomogeneous perfect magnetofluid solutions we have presented the basic equations and formulation of the line element and proved that the metrics are generated by the solutions to a system of coupled first order differential equations. In the limit of vanishing magnetic field, recover. Present some explicit magnetofluid solutions of Einstein field equations.

10 ref

019054   Dhanalakshmi M;Rukmani K (Physics Dep, Bangalore Univ, Bangalore-560 056) : A lock-in amplifier suitable for NMR and NQR spectrometers. J Instrum Soc India 2006, 36(3), 153-8.

An inexpensive lock-in amplifier suitable for cw NMR and cw NQR spectrometers has been built and is described in this paper. The heart of the instrument is the phase-sensitive detector and MOSFETs 3N138 are used as a series-shunt switch for this part. The input to the signal channel is a low noise pre-amplifier that can be included if needed or bypassed if input signal levels are high, with the help of a switch at the front panel. The reference channel uses the general purpose IC's μA 741 and MC 1458 for most of the functions. Phase shift between the signal and reference channels can be varied using digital techniques and the IC 74121 has been used for achieving this. The performance of the instrument was tested on a cw NMR spectrometer and a S/N ratio of about 100 was obtained with the standard sample of glycerine at room temperature.

6 illus, 7 ref

019053   Deo S;Datta S (Mathematics Dep, Allahabad Univ, Allahabad-211 002, Email: sd_mathau@yahoo.co.in) : Slow flow past a slightly deformed porous sphere. Ultra Scient phys Sci 2006, 18(3M), 595-604.

Problem of symmetrical flow past a porous spheroid whose shape deviates slightly from that of a sphere is investigated. The Brinkman's equation for the flow inside the porous region and the Stokes equation for the free-flow region in their stream functions are used. As boundary conditions, continuity of velocity and surface stress across the porous surface are employed. Explicit expressions are obtained for both the inside and outside flow fields to the first order in small parameter characterizing the deformation. As a particular case, the flow past a porous oblate spheroidal particle is considered and the drag experienced by it is evaluated through a simple analytical formula. The dependence of drag coefficient on permeability for porous oblate spheroid is presented graphically and discussed. The earlier results reported for a perfect porous sphere and for a rigid oblate spheroid, are then deduced from the present analysis.

11 ref

019052   Das S R (Phys and Astronomy Dep, Univ of Kentucky, Lexington, KY 40506, USA, Email: das@pa.uky.edu) : 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. Wel1 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. Describes some of these approaches.

27 ref

019051   Das D;Ahmed G A;Choudhury A;Mazumder G K D (Physics Dep, North Gauhati College, Guwahati-781 031) : Studies on water vapour droplet size distribution using a newly designed and fabricated air quality monitoring system. J Instrum Soc India 2006, 36(3), 174-82.

Newly designed and fabricated laser based air quality monitoring with PC based data acquisition system where synthesis of the design principles of a nephelometer, a transmissiometer and a point visibility meter are attempted. Studies with humid air having different levels of nitrogen and carbon dioxide have been carried out and size distribution of water vapour droplets has been attempted by computational techniques involving Mie theory and processing of experimental data.

2 illus, 6 ref

019050   Chaudhary R C;Gupta U (Mathematics Dep, Rajasthan Univ, Jaipur-302 004, Email: rechaudhary@rediffmail.com) : MHD three dimensional Couette flow with transpiration cooling between two horizontal parallel porous plates. Ultra Scient phys Sci 2006, 18(3M), 587-94.

Couette flow between two horizontal parallel porous flat plates with transverse sinusoidal injection of the electrically conducting viscous incompressible fluid, at the lower plate and its corresponding removal by constant suction through the upper plate has been analyzed when both plates are at constant distance and in motion. Due to this type of injection velocity, the flow becomes three-dimensional. A magnetic field of uniform strength is applied normal to the plates of the plates. To obtain the expression for the velocity and temperature fields, the method of solution for a small perturbation approximation is used. The effect of injection / suction velocity on the flow field, skin friction and heat transfer are reported and discussed with the help of graphs.

3 illus, 9 ref

019049   Camci U;Can Z;Nuthu Y;Sucu Y;Yazici D (Phys Dep, Akdeniz Univ, 07058 Antalya, Turkey, Email: ucamci@comu.edu.tr) : Dirac constraint analysis and symplecic structure of anti-self-dual yang-mills equations. Pramana J Phys 2006, 67(6), 1043-53.

Presents the explicit form of the symplectic structure of anti-self-dual Yang-Mills (ASDYM) equatlons m Yang's J- and K-gauges In order to establish the bi-Hamiltonian structure of this completely integrable system. Dirac's theory of constraints is applied to the degenerate Lagrangians that yield the ASDYM equations. The constraints are second class as in the case of all completely integrable systems which stands in sharp contrast to the situation in full Yang-Mills theory. Construcs the Dirac brackets and the symplectic 2-forms for both J- and K-gauges. The covariant symplectic structure of ASDYM equations is obtained using the Witten-Zuckerman formalism.It has been shown that the appropriate component of the Witten-Zuckerman closed and conserved 2-form vector density reduces to the symplectic 2-form obtained from Dirac's theory. Finally, presents the Backlund transformation between the J- and K-gauges in order to apply Magri's theorem to the respective two Hamiltonian structures.

14 ref

019048   Bhattacharyya S;Gupta A;Nakhate S G;Rao P M (Spectroscopy Div, Bhabha Atomic Res Centre, Mumbai-400 085, Email: pushpam@magnum.barc.ernet.in) : Measurement of storage time, estimation of ion number and study of absorption line profile in a Paul trap. Pramana J Phys 2006, 67(6), 1087-97.

Europium (Eu⁺) ions were confined in a Paul trap and detected by nonª destructive method. Storage time of Eu⁺ ions achieved in vacuum was improved by orders of magnitude employing buffer gas cooling. The experimentally detected signal was fitted to the ion response signal and the total number of ions trapped was estimated. It is found that the peak signal amplitude as well as the product of FWHM and the peak signal amplitude is proportional to the total number of trapped ions. The trapped ion secular frequency was swept at different rates and its effect on the absorption line profile was studied both experimentally and theoretically.

8 illus, 21 ref