015741   Goel P;Mittal R;Chaplot S L;Tyagi A K (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: knp@barc.gov.in) : Lattice dynamics of strontium tungstate. Pramana J Phys 2008, 71(5), 1135-9.

Reports measurements of the phonon density of states and the lattice dynamics calculations of strontium tungstate (SrWO₄). At ambient conditions this compound crystallizes to a body-centred tetragonal unit cell (space group 14_1/a) called scheelite structure. We have developed transferable interatomic potentials to study the lattice dynamics of this class of compounds. The model parameters have been fitted with respect to the experimentally available Raman and infra-red frequencies and the equilibrium unit cell parameters. Inelastic neutron scattering measurements have been carried out in the triple-axis spectrometer at Dhruva reactor. The measured phonon density of states is in good agreement with the theoretical calculations, thus validating the interatomic potential developed.

4 illus, 17 ref

015740   Ghosh G;Aswal V K;Varade D (UGC-DAE Consortium for Scientific Research, , Mumbai-400 085, Email: ghoshg@barc.gov.in) : Small angle neutron scattering study on the mixtures of pluronic L121 and anionic surfactant AOT. Pramana J Phys 2008, 71(5), 1063-67.

Small angle neutron scattering (SANS) experiments have been carried out on the micellar solutions containing mixtures of a hydrophobic triblock copolymer (L121, EO₅PO₆₈EO₅) and a hydrophobic anionic surfactant (AOT, sodium bis(2-ethylhexyl)sulphosuccinate) in water with varying ratio (R) of AOT to L121 for R = 0.15, 0.2, 0.3, 0.5 and 0.6. It is known that either L121 or AOT alone forms vesicles in water, but in the mixture with appropriate ratio of the two components a thermodynamically stable, isotropic solution of apparently small micelle-like aggregates is formed. We find that these micelles are prolate ellipsoidal.

1 illus, 1 table, 17 ref

015739   Geeha D;Yhilagavathi T;Ramesh P S;Rakkappan C (Physics Dep, Annamalai University, Annamalainagar-608 002, Email: gee_d72@yahoo.co.in) : Acoustical studies on solutions of surfactant - polymer in ethanol. Ultra Scient phys Sci 2009, 21(2), 239-44.

Ultrasonic velocity measurements have been made in an anionic surfactant sodium laureyl sulphate (SLS) with Dextrin (Dx), Hydroxy ethyl cellulose (HEC) and Hydroxy Propyl cellulose (HPC) in ethanol solution as a function of concentration, at a fixed frequency (2MHz). SLS with different polymers are prepared and dissolved in different concentration ratio (1:9 to 9:1). Limiting parameters have been used to explain the salvation of surfactant-polymer molecules.

2 illus, 2 tables, 10 ref

015738   Gautam S;Tripathi A K;Kamble V S;Mitra S; Mukhopadhyaya R (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: sidgau@barc.gov.in) : Diffusion of propylene adsorbed in Na-Y and Na-ZSM5 zeolites: nneutron scattering amd FTIR studies. Pramana J Phys 2008, 71(5), 1153-7.

Reports the quasielastic neutron scattering and FTIR studies on the dynamics of propylene adsorbed in Na-Y and Na-ZSM5 zeolites. QENS data show that although the mechanism of translational motion of propylene is jump diffusion in both the cases of Na-Y and Na-ZSM5 zeolites, the diffusivity is affected by the host size and is hindered in the case of Na-ZSM5. FTIR studies showed that guest-host interaction in Na-ZSM5 is stronger than that in Na-Y zeolite corroborating the QENS results.

2 illus, 1 table, 10 ref

015737   Gautam S;Choudhury R R;Panicker L;Mitra S; Mukhopadhyay R (Solid State Phsics Div, Bhabha Atomic Research Centre, Mumbai-400 085) : Phase transitions in liquid crystal 60.4 (p-n-hexyloxybenzylidine-p'-n-butylaniline). Pramana J Phys 2008, 71(5), 1159-64.

DSC measurements on p-n-hexyloxybenzylidine-p'-n-butylaniline (60.4) showed that the crystalline to liquid crystalline (K-SH) transition at 33.7°C observed in the heating cycle does not revert even when the sample is cooled down to -100°C. Hence it is inferred that a physically stable supercooled liquid crystalline phase is formed on cooling 60.4. To investigate the K-SH transition further the techniques of polarized microscopy and X-ray diffraction were used which concurred with the DSC results. Quasielastic neutron scattering measurements carried out to study the re-orientational motions in the ordered phases of 60.4 (K and SH) show that while in the crystalline phase (at RT) the re-orientational motion is found to involve only the core of the molecule, in the SH phase (at 45°C) the dynamics involves the whole molecule and this motion is found to persist even when the sample cools back to room temperature corroborating the results of the DSC, microscopy and X-ray diffraction.

4 illus, 10 ref

015736   Garud S L;Mahajan N K;Saraf K B (P.G. Physics Dep, Pratap College, Amalner-425 401, Email: sl.garud@rediffmail.com) : Gel grown mixed crystals of Ba_xCa_1-x(IO₃)₄. Bull Mater Sci 2009, 32(2), 187-92.

Growth of mixed crystals of Ba_x Ca_1-x (IO₃)₄ were carried out with simple gel method. The effect of various parameters such as pH of gel solution, gel concentration, gel setting time, concentration of reactants on the growth was studied. Crystals having different morphologies and habits were obtained. The grown crystals were characterized by XRD, FT-IR, EDAX, TGA, DTA and DSC.

5 illus, 5 tables, 16 ref

015735   Desai S S;Shaikh A M (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: shaikham@barc.gov.in) : Performance studies on high pressure 1-D position sensitive neutron detectors. Pramana J Phys 2008, 71(5), 1183-8.

The powder diffractometer and Hi-Q diffractometer at Dhruva reactor make use of five identical I-D position sensitive detectors (PSDs) to scan scattering angles in the range 3° to 140°. In order to improve the overall throughput of these spectrometers, it is planned to install a bank of 15 high-efficiency and high-resolution PSDs arranged in three layers with five PSDs in each layer. With each high pressure PSD (^{3He 10 bar + Kr 2 bar) showing the efficiency gain of 1.8 at 1.2 Angstrom, detector bank is expected to show overall gain of 5.5 times the present detection efficiency and reduction in data collection time by equivalent factor. The I-D PSDs are developed in batches of five, and are characterized so that all PSDs operate at uniform parameters such as position resolution, uniformity of efficiency and linearity of response. Position spectrum indicates the differential position resolution to be ~1 mm and integral position resolution to be 3-4 mm. Broadening of position spectrum at the extreme end of sensitive length of PSD is analysed using fine shift of the beam. Dependence of position resolution and dynamic range of output pulse on the input impedance of pre-amplifier is also presented.}

6 illus, 1 table, 4 ref

015734   Choudhury R R;Chitra R (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: rajul@barc.giv.in) : Single crystal neutron diffraction study of triglycine sulphate revisited. Pramana J Phys 2008, 71(5), 911-15.

In order to get the exact hydrogen-bonding scheme in triglycine sulphate (TGS), which is an important hydrogen bonded ferroelectric, a single crystal neutron diffraction study was undertaken. The structure was refined to an R-factor of RF^{2 0.034. Earlier neutron structure of TGS was reported with a very limited data set and large standard deviations. The differences between the present and the earlier reported neutron structure of TGS are discussed.}

1 illus, 2 tables, 10 ref

015733   Chodankar S;Aswal V K;Kohlbrecher J;Vavrin R; Wagh A G (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: Shirishc@barc.gov.in) : Small angle neutron scattering studies on protein denaturation induced by different methods. Pramana J Phys 2008, 71(5), 1021-5.

Small angle neutron scattering (SANS) has been used to study conformaªtional changes in protein bovine serum albumin (BSA) as induced by varying temperature and in the presence of protein denaturating agents urea and surfactant. BSA has prolate ellipsoidal shape and is found to be stable up to 60°C above which it denaturates and subsequently leads to aggregation. The protein solution exhibits a fractal structure at temperatures above 64°C, with fractal dimension increasing with temperature. BSA protein is found to unfold in the presence of urea at concentrations greater than 4 M and acquires a random coil Gaussian chain conformation. The conformation of the unfolded protein in the presence of surfactant has been determined directly using contrast variation SANS measurements by contrast matching surfactant molecules. The protein acquires a random coil Gaussian conformation on unfolding with its radius of gyration increasing with increase in surfactant concentration.

3 illus, 3 tables, 8 ref

015732   Chitra M;Palaniswamy S (Physics Dep, P.S.G. College of Arts and Science, Coimbatore-641 014, Email: palazhamni_5003@yahoo.com) : Growth and characterisation of nonlinear optical material: alanine barium chloride. Rasayan J Chem 2010, 3(1), 145-50.

Single crystals of Alanine Barium Chloride (ABC), a semi organic nonlinear optical material has been grown from solution by slow evaporation at ambient temperature. The growth of crystals has been carried out at various pH values and the growth ws confirmed at pH 5.7. The chemical composition of the grown crystals was determined by the FTIR spectra. The crystalline nature and its various planes of reflections were observed by the powder XRD and single crystal XRD. The structure is built from alternate layers of L-alanine organic molecules and inorganic layers consisting of Ba^{+ ions and Cl- ions. The Hardness of the crystal was studied by Vickers micro hardness measurement. The transmittance and absorption of the crystal was studied by UV-Vis spectrometer.}

4 illus, 6 ref

015731   Carlile C J;Vettier C;Carlsson P (The European Spllation Source Scandinavia Secretariat, , Algatan 4, Laund Sweden, Email: colin.carlile@nuclear.lu.se) : Towards the construction of the European spallation source - the Scandinavian experience. Pramana J Phys 2008, 71(5), 890.

The possible realization of the European spallation source has been a long and winding story. However, thanks to the conjunction of a number of events it now looks highly probable that in 2008 there will indeed be a decision on the site and on a funding partnership of European countries who will together build and operate this long-pulse spallation neutron source. Currently there is a reference design comprising of a 632 m long proton accelerator which will deliver 2 ms pulses of protons to a liquid metal target with 22 instruments receiving thermal and cold neutron beams and providing unprecedented data rates. Lund is one of the two consortia competing to build the ESS - the ESS Scandinavia and a Hungarian-Spanish collaboration which is currently deciding on its preferred site. The Lund experience is one which highlights the many delicate steps which must be taken in order to get close to such decisions in a Europe of 30 plus nations. Of particular interest is the Energy Management Strategy which ESS Scandinavia would implement if Lund were to be the eventual chosen site. This will be set into the context of the political iniatives to mitigate the effects of global warming.

015730   Bruckel T H;Kentzinger E;Mattauch S;Paul A; Rucker U;Voigt J (Oak Ridge National Laboratory, , USA, Email: zheludevai@ornl.gov) : Deeper look into magnetic nanostructures using advanced scattering methods. Pramana J Phys 2008, 71(5), 895.

Magnetic thin film systems and laterally patterned magnetic media are the baªsis of spintronic devices for information technology. In this contribution, we will show that D scattering under grazing incidence with polarization analysis is able to provide depth resolved information on magnetization, magnetic correlations and magne-ªD dynamics relevant for basic and applied research on nanostructured magnetic materials. It is well established that specular neutron reflectivity with polarization analysis from film systems and multilayers provides layer-resolved information on interface rough ªand on the laterally averaged magnetization. Off-specular diffuse scattering with polarization analysis gives access to lateral correlations, i.e. the detailed interface morªphology, the magnetic order of nanoscale objects (stripes or islands), the magnetic fluctuations or domain structure. Depending on the scattering geometry - reflectometry or incidence small angle neutron scattering (GISANS) - correlations on lateral length from the nanometer up to the 100 micrometer range become accessible. Close to total reflection, kinematical scattering theory breaks down and dynamical effects have to taken into account. Simulations in the distorted wave Born approximation (DWBA) allow one to extract quantitative parameters for a statistical model description. On several examples we will demonstrate the power of the method - from the magnetic fluctuations in remanent sputtered films via the magnetic structure of rare earth multilayers with competing interactions to the remagnetization process of exchange bias systems domain structures of laterally patterned giant magnetoresistance multilayers. Fiªwe will give an outlook on what will be possible on next generation instruments such the magnetism reflectometer MARIA of the Juelich Centre for Neutron Science (JCNS) at FRM=II.

015729   Bose P P;Mittal R;Choudhury N;Chaplot S L (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: knp@barc.gov.in) : Inelastic neutron scattering and lattice dynamics of ZrO₂, Y₂O₃ and ThSiO₄. Pramana J Phys 2008, 71(5), 1141-6.

Zirconia (ZrO₂), yttria (Y₂O₃) and thorite (ThSiO₄) are ceramic materials used for a wide range of industrial applications. The dynamical properties of these materials are of interest as they exhibit numerous interesting phase transitions at high temperªature and pressure. Using a combination of inelastic neutron scattering and theoretical lattice dynamics we have studied the phonon spectra and thermodynamic properties of these compounds. The experimental data validate the theoretical model, while the model enables microscopic interpretations of the observed data. The calculated thermodynamic properties are in good agreement with the experimental data.

3 illus, 28 ref

015728   Bose A;Chatterjee K;Chakravorty D (DST Unit of Nano Science, Indian Association for the Cultivation of Science, Kolkata-700 032, Email: mlsdc@iacs.res.in) : Metal-semiconductor nanojunctions and their rectification characteristics. Bull Mater Sci 2009, 32(3), 227-30.

Junctions of silver-copper oxide and silver-zinc oxide, respectively were prepared within the pores of diameters, 20 nm, in anodic aluminium oxide membranes. Voltage-current characteristics were measured over the temperature range 373-573 K which showed rectification behaviour. Using the standard equation the difference between the work functions of the metal and the semiconductor was calculated. This showed a variation with the temperature of measurement. This is explained as arising due to the effect of pressure generated as a result of thermal expansion of the metallic phases concerned between the electrodes. This is consistent with the theoretical prediction of Fermi level shifting of the semiconductor within the bandgap as a function of pressure.

3 illus, 2 tables, 18 ref

015727   Biswas B;Kumar V;Chouksey S;Krishnagopal S (Beam Physics and FEL Lab, Raja Ramanna Centre for Advanced Technology, Indore-452 013, Email: bbiswas @cat.ernet.in) : (NULL). Pramana J Phys 2008, 71(6), 1321-33.

A compact ultrafast terahertz (CUTE) free-electron laser (FEL) is being developed at the Raja Ramanna Centre for Advanced Technology (RRCAT), Indore. The undulator required for the CUTE-FEL has recently been developed. We have designed, built and characterized a variable gap, 5 cm period, 2.5 m long pure permanent magnet undulator in two identical segments. The tolerable error in the magnetic field was 137 in rms, and we have measured it to be 0.737. The obtained rms phase shake is around 2°. To ensure that the trajectories do not have an exit error in position or angle, corrector coils have been designed. Shimming coils have been applied for both the undulator segments to reduce the amplitude of the betatron oscillations in the vertical trajectory. Details of novel corrector coils and soft iron shims are given and their performance is discussed.

11 illus, 2 tables, 16 ref

015726   Bhattacharjee J;Verma G;Aswal V K; (Chemistry Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: hassan@barc.gov.in) : Small angle neutron scattering study of doxorubicin-surfactant complexes encapsulated in block copolymer micelles. Pramana J Phys 2008, 71(5), 991-5.

Self-assembling behaviour of block copolymers and their ability to evade the immune system through polyethylene oxide stealth makes it an attractive candidate for drug encapsulation. Micelles formed by polyethylene oxide-polypropylene oxidepolyethylene oxide triblock copolymers (PEO-PPO-PEO), pluronic P123, have been emªployed for encapsulating the anti-cancer drug doxorubicin hydrochloride. The binding affinity of doxorubicin within the micelle carrier is enhanced through complex formation of drug and anionic surfactant, aerosol OT (AOT). Electrostatic binding of doxorubicin with negatively charged surfactants leads to the formation of hydrophobic drug-surfactant comªplexes. Surfactant-induced partitioning of the anti-cancer drug into nonpolar solvents such as chloroform is investigated. SANS measurements were performed on pluronic P123 micelles in the presence of drug-surfactant complex. No significant changes in the structure of the micelles are observed upon drug encapsulation. This demonstrates that surfactantdrug complexes can be encapsulated in block copolymer micelles without disrupting the structure of aggregates.

4 illus, 8 ref

015725   Bera A K;Yusuf S M;Jain A (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: smyusuf@barc.gov.in) : Structural and magnetic properties of the layered compound Ca_2.375La_0.125 GaMN₂O₈. Pramana J Phys 2008, 71(5), 917-21.

The brownmillerite-type layered compound Ca_2.375La_o.125Sr_O.5GaMn₂O₈ has been synthesized. The crystal and magnetic structures have been refined by the Rietveld analysis of the neutron powder diffraction patterns at 300 and 20 K. This compound crystallizes in the orthorhombic symmetry under the space group Pcm2₁ (a = 5.447(2), b = 11.359(4) and c = 5.322(2) Angstrom). The compound is found to be antiferromagnetic at 20 K. The ordered Mn magnetic moment, aligned along the crystallographic b-direction, is derived to be 2.53(5) μB per Mn ion at 20 K.

2 illus, 1 table, 6 ref

015724   Beldev Raj (NO, Indira Gandhi Centre for Atomic Research, Kalpakkam-603 102) : Materials science research for sodium cooled fast reactors. Bull Mater Sci 2009, 32(3), 271-83.

Gives an insight into basic as well as applied research being carried out at the Indira Gandhi Centre for Atomic Research for the development of advanced materials for sodium cooled fast reactors towards extending the life of reactors to nearly 100 years and the burnup of fuel to 2,00,000 MWd/t with an objective of providing fast reactor electricity at an affordable and competitive price.

12 illus, 1 table, 44 ref

015723   Bahadur J;Sen D;Mazumder S;Ramanathan S (Solid State Physics Div, Bhabha Atomic Research Centre, Mumabai-400 085, Email: jbahadur@barc.gov.in) : Effect of heat treatment on pore structure in nanocrystalline NiO: a small angle neutron scattering study. Pramana J Phys 2008, 71(5), 765-70.

Nanocrystalline nickel oxide powders were calcined at 300, 600 and 900°C and pore structure evolution was followed by small angle neutron scattering (SANS). Pore size distributions at two widely separated size ranges have been revealed. Shrinkage of larger-sized pore with reduction in polydispersity has been observed with increasing heat treatment temperature. The pore structures at various heat treatment temperatures do not scale. This has been attributed to the grain boundary diffusion leading to an asymmetric shrinkage of the pores.

4 illus, 8 ref

015722   Bahadur J;Sen D;Mazumder S;Aswal V K;Bedekar V;Shukla R;Tyagi A k (Solid State Physics Div, , Mumbai-400 085, Email: jbahadur@barc.gov.in) : Effects of sintering on microstructure and dielectric response in YCrO₃ nanoceramic. Pramana J Phys 2008, 71(5), 959-53.

Effects of sintering on pore morphology and dielectric response have been investigated. Pore structure has been probed by small angle neutron scattering (SANS). It has been observed that the size distribution becomes less polydisperse with a slight modification in the distribution as sintering temperature is increased. Dielectric response in the frequency range 0.02-1000 kHz is significantly altered by modification of pore strucªture because of sintering. A transition from non-Debye type to near-Debye type response has been observed as the sintering temperature is increased.

5 illus, 1 table, 10 ref

015721   Aswal V K;Wagh A G (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: vkaswal@barc.gov.in) : Small angle neutron scattering study of temperature-independent formuation of mixed micellar structures. Pramana J Phys 2008, 71(5), 1045-9.

SANS measurements have been performed on mixed systems of ionic surfacªtant sodium dodecyl sulphate (SDS) and nonionic surfactant polyoxyethylene 10 lauryl ether (C12E10). The total concentration of the mixed system was kept fixed (10 wt%) and the ionic to nonionic surfactant ratio varied in the range 0 to 1. The temperature effect on the structures of mixed micelles has been studied for temperatures between 30 and 75°C. Micelles of pure ionic and nonionic surfactants show opposite trends when the temperature is increased. Sizes of pure ionic micelles decrease and those of nonionic micelles increase with increase in temperature. We show a formulation balancing these two effects which is temperature-independent and consists of about 25% of ionic surfactants in the mixed system. Contrast variation SANS measurements by contrast matching one of the surfactant components to the solvent suggest homogeneous single mixed micelles of the two components in the mixed systems.

3 illus, 2 tables, 9 ref

015720   Aswal V K;Vavrin R;Kohlbrecher J;Wagh A G (Solid State Physics Div, Bhabba Atomic Research Centre, Mumbai-400 085, Email: vkaswal@barc.gov.in) : Pressure-induced structural transition of nonionic micelles. Pramana J Phys 2008, 71(5), 1051-5.

Reports dynamic light scattering and small angle neutron scattering studies of the pre me-induced structural transition of nonionic micelles of surfactant polyoxyethylene 10 lauryl ether (CI2EI0) in the pressure range 0 to 2000 bar. Measurements have been performed on 1 wt% C12ElO in aqueous solution with and without the addition of KF. Micelles undergo sphere to lamellar structural transitions as the pressure is increased. On addition of KF, rod-like micelles exist at ambient pressure, which results in rod-like to lamellar structural transition at a much lower pressure in the presence of KF. Micellar structural transitions have been observed to be reversible.

4 illus, 8 ref

015719   Angappane S;Selvi N R;Kulkarni G U (Chemistry and Physics of Materials Unit and DST Union Nanoscience, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore-560 064, Email: kulkarni@jncasr.ac.in) : ZnO(101) films by pulsed reactive crossed-beam laser ablation. Bull Mater Sci 2009, 32(3), 253-8.

Employed pulsed reactive crossed-beam laser ablation (PRCLA) to deposit a (101) oriented ZnO film. In this method, a supersonic jet of oxygen pulse is made to cross the laser plume from a zinc metal target while being carried to the Si(111) substrate. The obtained deposit was nanocrystalline ZnO as confirmed by a host of characterization techniques. When the substrate was held at varying temperatures, from room temperature to 900°C, the crystallinity of the obtained films increased as expected, but importantly, the crystallographic orientation of the films was varied. High substrate temperatures produced the usual (001) oriented films, while lower substrate temperatures gave rise to increasingly (101) oriented films. The substrate held at room temperature contained only the (101) orientation. The film morphology also varied with the substrate temperature, from being nanoparticulate to rod-like deposits for higher deposition temperatures. Surprisingly, the (101) orientation showed reactivity with acetone forming carbonaceous nanostructures on the surface.

6 illus, 28 ref

015718   Anderson I S (NO, Oak Ridge National laboratory, USA, Email: andersonian@sns.gov) : Spallation neutron source: new opportunities. Pramana J Phys 2008, 71(5), 887.

The spallation neutron source (SNS) facility became operational in the spring of 2006, and is now well on its way to become the world-leading facility for neutron scatterªing. Furthermore, the SNS and the HFIR reactor facility, newly outfitted with a brilliant cold source and guide hall, were brought together within a single Neutron Sciences Directorate at ORNL providing the opportunity to develop science and instrumentation programs which take advantage of the unique characteristics of each source. SNS and HFIR will both operate as scientific user facilities. Access to these facilities is being managed under an integrated proposal system, which also includes the Center for Nanophase Materials Sciences (CNMS) and the electron microscopes in the Shared Research Equipment (SHARE) program. Presently, SNS has three instruments operating in the user program and seven more will begin operations in 2008. When complete, the facility will accommodate 25 instruments enabling researchers from the United States and abroad to study materials science that forms the basis for new technologies in telecommunications, manufacturing, transportaªtion, information technology, biotechnology, and health.

015717   Aldona R (NO, Institute of Atomic Energy, 05-400 Swierk-Otwock, Poland, Email: aldonar@cyf.gov.pl) : Small angle neutron scattering study of two nonionic surfactants in water micellar solutions. Pramana J Phys 2008, 71(5), 1079-83.

Two classic non ionic surfactants - C₁₄E₇ (heptaethylene glycol monotetra-decyl ether) and C₁₀E₇ (heptaethylene glycol monodecyl ether) were investigated in heavy water solution for concentration c = 0.17% (dilute regime) at different temperatures in the range t = 10-35°C by small angle neutron scattering (SANS) method. In the case of C₁₄E₇ surfactant - for all temperatures at c = 0.17% there are two axial ellipsoidal micelles with longer axis 15 nm at l0°C and 49.5 nm at 35°C in investigated solutions. For C₁₀E₇ surfactant at the same concentration of solution and temperature - two axial ellipsoidal micelles were observed, too. The longer axis is equal to 7.5 nm at l0°C, 9 nm at 20°C and at 35°C this axis is equal to 12 nm. Micelles of C₁₀E₇ nonionic surfactant are smaller than those of C₁₄E₇ surfactant in the same experimental conditions.

4 illus, 11 ref

015716   Acharya P;Desai R;Aswal V K;Upadhyay R V (Physics Dep, K K Shah Jarodwala Maninagar Science College, Ahmedabad, Email: rvu@bhavuni.edu) : Structure of Co-Zn ferrite ferrofluid: a small angle neutron scattering analysis. Pramana J Phys 2008, 71(5), 1069-74.

A hydrothermal synthesis route is used to synthesize nanomagnetic particles of CO_0.3Zn_0.7Fe₂O₄ ferrite ferrofluids with particle diameter ranging from 5.5-9 nm. XRD analysis shows the formation of a single phase spinel structure. EDX results confirm the stoichiometric composition of the cations. Small angle neutron scattering technique is used to determine the size and size distribution of Co_0.3Zn_0.7Fe₂O₄ ferrofluid. The sizes thus obtained are in the range of 5.4 to 8.4 nm. These results are in agreement with magnetic measurements.

3 illus, 1 table, 5 ref

015715   Abbas S;Wagh A G;Strobl M;Treimer W (Solid State Physics Div, IBhabha Atomic Research Centre, Mumbai-400 085, Email: abbas@barc.gov.in) : Neutron forward diffraction by single crystal prisms. Pramana J Phys 2008, 71(5), 1109-14.

Derived analytic expressions for the deflection as well as transmitted fraction of monochromatic neutrons forward diffracted by a single crystal prism. In the vicinity of a Bragg reflection, the neutron deflection deviates sharply from that for an amorphous prism, exhibiting three orders of magnitude greater sensitivity to the incidence angle. We have measured the variation of neutron deflection and transmission across a Bragg reflection, for several single crystal prisms. The results agree well with theory.

4 illus, 11 ref

015714   Abbas S;Wagh A G (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085) : Pancharatnam geometric phase originating from successive partial projections. Pramana J Phys 2008, 71(5), 1115-22.

The spin of a polarized neutron beam subjected to a partial projection in another direction, traces a geodesic arc in the 2-sphere ray space. We delineate the geometric phase resulting from two successive partial projections on a general quantal state and derive the direction and strength of the third partial projection that would close the geodesic triangle. The constraint for the three successive partial projections to be identically equivalent to a net spin rotation regardless of the initial state, is derived.

2 illus, 4 ref

013606   Suriyakala R;Shanmugavel R;Sriramachandran P (Physics Research Center, V.H.N.S.N. College, Virudhunagar-626 001, Email: sri_ramnivash@rediffmail.com) : Thermal parameters for Mg_0.8 Zn_0.2 So₄ 7H₂O crystals. Asian J Spectrosc 2009, 13(4), 105-7.

Slow evaporation method was followed to grow Mg_0.8 Zn_0.2 SO₄ 7H₂ O single crystals from the aqueous supersaturated solutions of 1.1 and 1.2 molar concentration. The crystals were characterized by using the X-ray diffraction pattern. From the XRD data, the thermal parameters like Debye - Waller factor, mean - square amplitude of vibration, Debye frequency and Debye temperature were calculated using least square fitting method. The results show that thermal parameters depend on super saturation.

1 table, 10 ref

013605   Sunil S;Blair D G (NO, Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar-382 428, Email: sunil.98@gmail.com) : Vacuum system requirement for a 5 km baseline of gravitational-wave detector. Bull Indian Vacuum Soc 2008, 11(3), 3-7.

Gravitational wave laser interferometer detectors use a pair of cylindrical vacuum tubes, placed perpendicular to each other, in which the partial pressure of hydrogen is required to be ~ 10^{-9 mbar to obtain residual gas-phase noise of ~10-25 Hz-1/2. It is advantageous to use longer arm-length interferometers, as the total strain sensitivity decreases proportionally to arm length. The tube diameter of the interferometer is set by the light scattering requirements, and also by the possible need for additional optical cavities within the tube. Vacuum performance depends critically on the stainless-steel outgassing rate as well as the conductance of the tube. A novel method of low temperature vacuum baking using solar bakeout technique is also mentioned.}

2 illus, 2 tables, 9 ref

013604   Sharma A;Hussain M;Sharma G;Roy B;Kumari V (Physics Dep, R.D.S. College, Muzaffarpur, Bihar) : Study of the change of the spin wave spectrum with decreasing lattice constant by density functional theory. Bull pure appl Sci-Sect D 2009, 28(2), 137-40.

Calculated spin wave spectra for different lattice constant. The results for the spin wave spectra along the high symmetry lines in the Brillouin zone were observed for reduced lattice constant (a) and for an extended lattice constant. The spin wave energies increase when the lattice constant decreases. The Kohn anomalies especially around the H point were clearly visible for all considered lattice constants. The spin wave stiffness increases with decreasing lattice constant and there was an indication that the influence of the quartic terms becomes smaller at the same line. All coupling were accounted for in the calculation of spin wave energies because periodic boundary conditions based on the extended Bloch theorem. The exchange parameters of a Heisenberg model were determined also. The computed pressure dependence of critical temperature is also affected.

7 ref

013603   Semwal P;el al. (NO, Institute of Plasma Research, Bhat, Gandhinagar-382 428, Email: prats@ipr.res.in) : Sensitivity of a quadrupole mass analyzer and a bayard alpert gauge with changes in temperature and gas composition. Bull Indian Vacuum Soc 2009, 12(1), 11-14.

The quadrupole mass analyzer (QMA) and the Bayard Alpert (BA) gauge are used widely in Tokamaks (fusion devices) to study the composition of residual gases and to measure the total pressure inside the vacuum chambers of these devices. The partial pressure analysis of the spectra provides useful information about the sources of impurities or leaks in these chambers. Cryostat chamber of SST-1 Tokamak encloses cold masses like Iiquid nitrogen panels and liquid helium cooled coils. A QMA or a BA gauge mounted on the cryostat chamber is therefore subjected to gases at low temperatures. An experiment was performed to study the behaviour of these gauges under these conditions. The results will be presented in this paper.

4 illus, 5 ref

013602   Sawant S A;Inampudi S (Physics Dep, , Smt. Kashibai Navale College of Engineering) : Conventional use of concentrated solar power and its advances in today's world. Asian J envir Sci 2010, 4(2), 242-5.

5 illus, 8 ref

013601   Sarojini E;Jayanthi S (Civil Engineering Dep, Sri Ramakrishna Engineering College, Coimbatore-641 022) : Effect of solar radiation on disinfection of infectious biomedical wastes. J envir Sci Engng 2010, 52(2), 93-6.

The present investigation is an attempt to study the effect of solar treatment for disinfection of biomedical wastes with and without lime stabilization process. The laboratory experiments were conducted using box type solar disinfector with and without lime. The study involves the determination of parameters, such as COD, total solids, volatile solids, electrical conductivity, alkalinity and microbial colony count at different stages of disinfection. The reduction percentages of COD and alkalinity were 77% and 76% respectively for solitary solar disinfection, whereas for solar disinfection with lime stabilization COD and alkalinity were reduced to 65.79% and 70.87% respectively. The microbial colony count due to only solar disinfection was reduced from 15x10^{11 microbes/mL to 9 x 107 microbes/mL whereas due to solar disinfection with lime stabilization, the microbial colony count reduced to 8 x105 microbes/mL within 6 hrs. There was a notable reduction in the parameters, which suggests that pathogens of biomedical waste can be effectively destroyed using solar disinfection with lime stabilization process.}

1 illus, 8 tables, 12 ref

013600   Saha T K;Ray A K (Laser & Plasma Technology Div, , 1Ex. Director, BTDG, Bhabha Atomic Research Centre, Mumbai-400 085, Email: tanmay@barc.gov.in) : Vacuum-the ideal environment for welding of reactive materials. Bull Indian Vacuum Soc 2008, 11(4), 3-7.

All reactive metals and their alloys, during welding process, are subjected to contamination by the gases present in the atmosphere which affects the strength, elasticity and corrosion resistance behavior of the weld. Although the use of shielded electrodes and inert gas surrounding during welding could reduce the difficulty of welding to a great extent, still the quality of the weld is not suitable as far as the nuclear and aerospace applications are concern. Electron beam has been recognized as a versatile tool for we/ding of reactive materials as the process is carried out under high vacuum, which is being considered to be the best inert environment. A number of reactive materials have been welded by electron beam in BARC and elsewhere for aerospace, accelerator, nuclear and defense applications. A brief description of the EB welding process for some of the above materials will be given in this paper with a discussion about their post weld mechanical properties and corrosion resistance behavior.

2 illus, 16 ref

013599   Ray K (NO, , Proof and Experimental, Chandipur-756 025, Email: kunalrayind@gmail.com) : 2-D shape fitting for locating exploding projectile from explosion patch. Def Sci J 2010, 60(3), 238-43.

For test and evaluation of a proximity fuze, it is necessary to know the distance offset of the exploding ammunition round, fitted with the fuze, from a specific target. If the event is recorded using in-line high-speed photography the event of explosion can be resolved in time, and it becomes necessary to ascertain the position of the round, wrt the target, as it is exploding. An estimation of intensity centroid position fails as the flash is non-uniform in nature and is partially occluded by the exploding round. This paper is about an approach to find the location of the round using 2-D shapes fitting of the explosion patch.

7 illus, 1 table, 15 ref

013598   Ranjan A;Kumar A;Chaudhary J;Kumar A;Jee M (Physics Dep, B.R.A. Bihar Univ, Muzaffarpur, Bihar) : Effect of bychkov - rashba spin-orbit coupling in the optical transition spectra and energy levels of parabolic dots. Bull pure appl Sci-Sect D 2009, 28(2), 117-20.

Studies the effect of Bychkov-Rashba spin-orbit coupling in the optical transition spectra and the energy levels of two parabolic dots placed vertically and interacting only through the Coulomb interaction. The zero field spin hot spots in our vertically coupled quantum dots manifests in the dipole transition energies. For coupled quantum dots with one dot containing two electrons while the other with a single electron, the spin-orbit effect strongly depends on the inter dot separation. In the quantum dots the electric field can arise from the inversion asymmetry of the potential restricting the motion of the electrons to a two dimensional plane. Another source for the electric field in the quantum dot is the potential confines the electron into the dot in the two dimensional plane.

7 ref

013597   Prasad N K;Ram Y;Sabharwal T P;Pathak K; Manish Kumar;Matkar A W;Rajawat R K (Mechanical Design and Prototype Development Section, , Physics Group, Bhabha Atmoic Research Centre, Mumbai-400 085, Email: nkp20@yahoo.com) : UHV compatible AI to SS joining through electro magnetic forming technique. Bull Indian Vacuum Soc 2008, 11(4), 9-13.

Fusion welding, which is the most versatile and widely used method of metallurgical bonding, can be troublesome in certain applications like dissimilar metal joining for Ultra High Vacuum requirements. Welding of Stainless Steel to Aluminum by conventional technique is very difficult due to thermal & metallurgical incompatibility. Consequently a number of non-conventional specialized joining techniques were developed. Joining of SS to Al by Electro Magnetic Forming (EMF) method is an effort in this direction. The paper discusses in detail the joining process, joint design and the results achieved.

4 illus, 1 table, 13 ref

013596   Nair K P R;Mader H (NO, Cochin Univ of Science and Technology, Cochin-628 022, Email: kprnair@yahoo.co.uk) : Fourier transform microwave spectrum of o-chlorotoluene in an excited vibrational state. Asian J Spectrosc 2009, 13(4), 75-82.

The microwave spectrum of orthochlorotoluene has been studied by means of waveguide Fourier transform microwave spectroscopy in the frequency region from 8 to 16 GHz. The analysis of the spectrum has given accurate values of the chlorine nuclear quadrupole hyperfine constants for both isotopic species in an excited vibrational state namely xaa = -67.59(14) MHz, xbb = 36.44(15) MHz for the ^{35 C1 species, and xaa= -53.54(47) MHz, Xbb = 29.19(15) MHz for the 37 C1 species. The results are compared with the ground state hyperfine constants.}

4 tables, 20 ref

013595   Momin T;Bhowmick A;Gadkari S C (Technical Physics & Prototype Engineering Div, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085, Email: ashokb@barc.gov.in) : Development of a nano electrospray time of flight setup. Bull Indian Vacuum Soc 2009, 12(1), 3-7.

Certain complexities often encountered in the experimentation using the electrospray technique apart from the occurrence of multiply charged species. The process being essentially happening at atmospheric pressure, it is a nontrivial task to couple it with the time-of-flight mass spectrometer without affecting the dynamic range. Second, ions being created from an explosion of the charged droplet, the spatial and energy spread are rather broad that hampers the resolution of the spectrometer. Moreover, formation of large droplets often causes severe discharge with the ground interface of the inlet system causing damage to the stability of electrical conditions. In this paper, we describe a new development in that these issues are circumvented while coupling it to a time-of-flight mass spectrometer.

6 illus, 27 ref

013594   Mistry K A;Rustagi P;Patel I B (Physics Dep, Veer Narmad South Gujarat Univ, Surat, Gujarat-395 007) : Study of hardness of NaF, NaCl & NaF+NaCl crystals grown by solution evaporation method at ambient temperature. Bull pure appl Sci-Sect D 2009, 28(2), 127-36.

Generally Alkali Halide crystals are ionic crystals which are highly soluble in water. From them NaF and NaCl are most popular materials due to their optical properties. Therefore author have grown these crystals by solution evaporation method at ambient temperature. In this paper, measurement of the mechanical property named hardness of NaCl, NaF and NaCl + NaF-mixed crystals is done in two different ways. First keep the load constant, loading time constant and by varying the temperature hardness was measured. Then keep the temperature constant, loading time constant and by varying the load hardness was measured. The graph of Hardness Vs Load and Hardness Vs Temperature are plotted for all these three crystals. The results and conclusions are reported in this paper.

5 illus, 6 tables, 8 ref

013593   Mengesha M;Redi M;Asfaw A;Ghoshal S K;Mohan D;Sharma S (Physics Dep, Addis Ababa Univ, P.O. Box 1176, Addis Ababa, Ethiopia, Email: mmenbb@yahoo.com) : Fluorescence quenching method for the determination of caffeine in coffee seeds. Asian J Spectrosc 2009, 13(4), 83-8.

Fluorescence quenching method is exploited to determine the caffeine content of coffee beans in water solution. This method is based on correlating the decrease in fluorescence intensity of rhodamine molecule due to the quenching effect of caffeine, which is due to the energy transfer from an excited rhodamine (donor) molecule to coffee or caffeine (acceptor) molecule. The decrease in rhodamine fluorescence intensity is found to be a linear function of caffeine concentration. The concentration range is from 1.0 x 10^{-5 mol/L of caffeine in 2.85 x 10-6 mol/L of rhodamine solution to 5 x 105 mol/L of caffeine in 2.85 x 106 mol/L of rhodamine solution. The caffeine content of coffee was determined and its value is 0.95 ± 0.01%. The results found in this method have a very good correlation with the results determined using established methods. Further, the mechanism of quenching was studied using 1R spectroscopy and the result indicates that the carbonyl groups (C=O) are the functional groups that play a prominent role in caffeine dye interaction.}

4 illus, 20 ref

013592   Manivannan R;Daniel A;Srikanth I;Anil Kumar; Sarkar R;Ghoshal P;Devi R (NO, Advanced Systems Laboratory, Hyderabad-500 058, Email: rajdeepsarkar@dmrl.drdo.in) : Thermal stability of zirconia-coated multiwalled carbon nanotubes. Def Sci J 2010, 60(3), 337-42.

Sol-gel method has been used to coat multiwalled carbon nanotubes (MWCNTs) with zirconia at room temperature and the coated tubes were sintered at high temperature. The samples were characterised by Raman spectroscopy, x-ray diffraction, environmental scanning electron microscope, transmission electron microscopy, and energy-dispersive x-ray analyses. The performance of the coated-MWCNTs was investigated as a function of temperature. The TGA studies indicated that sintering of coated-MWCNTs has improved its oxidation resistance and this improvement is related to the proper selection of sintering temperature.

7 illus, 27 ref

013591   Lo C Y (NO, Applied and Pure Research Institute, 7 Taggart Drive, Unit E, Nashua, NH 03060 USA) : Detection of the gravitational wave with the LIGO and Einstein's theoretical errors on measurements. Bull pure appl Sci-Sect D 2009, 28(2), 87-103.

The design of the LIGO was according to the calculations of Thome's equation which is based on Einstein's theory of measurement. However, there is no valid justification for his theory of measurement. Experimentally the observed bending of light is also against Einstein's theory of measurement, but supports the Euclidean-like structure of a frame for measuring the distance. Nevertheless, analysis shows that the wave-induced phase delay of Thorne, is valid although it is due to the changed light speed but not changing the length of arms. Thorne assumed that gravity would not induce any change of the light speed, in addition to that the LIGO were built on a free falling frame. These differences are distinguishable since the change of light speed is unrelated to the movement of end masses. Thus, an additional benefit of the LIGO is its potential ability to test Einstein's theory of measurements and thus would confirm Einstein's equivalence principle further, Moreover, there are other experiments such as measuring local light speeds would also verify the validity of Einstein's equivalence principle.

53 ref

013590   Kanitkar P;Sen S;Muthe K P;Aiyer R C;Gupta S K (Physics Dep, Pune Univ, Pune-411 007, Email: drgupta@barc.gov.in) : Synthesis and characterization of copper nanostructures on silicon substrates. Bull Indian Vacuum Soc 2008, 11(3), 9-13.

Vacuum vapour deposition technique has been utilized for the synthesis of copper nanostructures on Si(111), Si(100) and Si(110) substrates at an optimized substrate temperature of 750°C. The samples are characterized by SEM, AFM and XPS. Their morphology is strongly governed by orientation of substrate. It is possible to realize the growth of triangular, square like and rod shaped geometries by choosing an appropriate orientation. This variation is attributed to the surface reconstruction which occurs at high temperature.

8 illus, 12 ref

013589   Iyanar M;Prakash J T J;Muthamizhchelvan C; Ponnusamy S (Physics Dep, National College, Trichy-620 001, Email: inrnct@gmail.com) : Growth and characterization of tetra (Thiourea) potassium chloride (TTPC) a semiorganic NLO material. Bull pure appl Sci-Sect D 2009, 28(2), 105-15.

The growth and characterization of a nonlinear Tetra (thiourea) Potassium Chloride (TTPC) is reported. In the present study we have synthesized the Tetra (thiourea) Potassium Chloride (TTPC) by taking the appropriate ratio of thiourea and potassium chloride. The calculated amounts of the reactants were thoroughly dissolved in double distilled water and stirred well for about two hours using a magnetic stirrer. Then the mixture was evaporated to dryness, by heating below an optimum temperature of 60°C to prevent possible decomposition. The colorless crystalline sample of TTPC was obtained and dissolved thoroughly in double distilled water at 30°C to form a saturated solution. This was then filtered twice to remove suspended impurities and allowed to crystallize by slow evaporation at 30°C. The harvested single crystal has been subjected to XRD, FTIR, TG/DTA, UV-Vis., etc in order to know its suitability for device fabrication. From the X-ray diffraction analysis we understood that the grown single crystal belongs to tetragonal crystal system having the lattice dimensions a=20.4854 Angstrum, b=20.6430 Angstrum, c=8.5278 Angstrum and volume V = 3578.7050 Angstrum.

8 illus, 2 tables, 17 ref

013588   Ghosh D;Deb A;Maiti S;Haldar S;Bera S; Sengupta R;Bhattacharyya R (Biren Roy Research Laboratory for Radioactivity and Earthquake Studies, School of Studies in Environmental Radiation and Archaeological Scienc, Kolkata-700 032, Email: dipakghosh_in@yahoo.com) : Assessment of alpha radioactivity in lipstick, nailpolish, toothpaste and vermilion using CR-39 detector. J envir Sci Engng 2010, 52(2), 117-20.

Human beings are always exposed to radiation from chemical cosmetics. In order to collect information regarding the radioactivity of chemical cosmetics used in our daily life, we studied the alpha radioactivity in different cosmetics samples, such as lipsticks, nail- polish, toothpaste and vermilion. The significant accumulation of radionuclide in and on the tissues, directly or indirectly exposed due to the lipsticks, toothpaste, vermilion, may cause health hazards. Different samples of these cosmetic materials (Indian and foreign brands) were collected from the local markets of Kolkata, India. CR-39-a useful solid state nuclear track detector (SSNTD) was used to detect alpha radioactivity of these samples. Such exhaustive measurement of radioactivity in lipsticks, nail-polish, toothpaste and vermilion has not been reported so far.

1 illus, 5 tables, 4 ref

013587   Chaudhuri D;Agrawal A (NO, Defence Electronics Application Laboratory, Dehradun-248 001) : Split-and-merge procedure for image segmentation using bimodality detection approach. Def Sci J 2010, 60(3), 290-301.

Image segmentation, the division of a multi-dimensional image into groups of associated pixels, is an essential step for many advanced imaging applications. Image segmentation can be performed by recursively splitting the whole image or by merging together a large number of minute regions until a specified condition is satisfied. The split-and-merge procedure of image segmentation takes an intermediate level in an image description as the starting cutest, and thereby achieves a compromise between merging small primitive regions and recursively splitting the whole images to reach the desired final cutest. The proposed segmentation approach is a split-and-merge technique. The conventional split-and-merge algorithm is lacking in adaptability to the image semantics because of its stiff quadtree-based structure. In this paper, an automatic thresholding technique based on bimodality detection approach with non-homogeneity criterion is employed in the splitting phase of the split-and-merge segmentation scheme to directly reflect the image semantics to the image segmentation results. Since the proposed splitting technique depends upon homogeneity factor, some of the split regions may or may not split properly. There should be rechecking through merging technique between the two adjacent regions to overcome the drawback of the splitting technique. A sequential-arrange-based or a minimal spanning-tree based approach, that depends on data dimensionality of the weighted centroids of all split regions for finding the pair wise adjacent regions, is introduced. Finally, to overcome the problems caused by the splitting technique, a novel merging technique based on the density ratio of the adjacent pair regions is proposed. The algorithm has been tested on several synthetic as well as real life data and the results show the efficiency of the segmentation technique.

5 illus, 27 ref

013586   Bayrakceken F;Tarhanci E (Optical Spectroscopy Div, Biomedical Engineering Dep, Yeditepe Univ, Istanbul, 34755, Turkey, Email: fubay@yeditepe.edu.tr) : Raman scattering of dibenzosuberone by high photon flux flash spectroscopy. Asian J Spectrosc 2009, 13(4), 89-93.

A number of photophysical properties of dibenzosuberone have been measured by flash photolysis of high photon flux, (10^{24 photon/pulse), excitation spectroscopy including prompt fluorescence, P and B-type of delayed fluorescences, triplet-triplet absorption, triplet decay and Raman scattering. The results are discussed and compared to those of molecules with similar structures, at room temperature and above.}

5 illus, 1 table, 15 ref

013585   Bayrakceken F (Optical Spectroscopy Div, Biomedical Engineering Dep, Yeditepe Univ, Istanbul, 34755, Turkey, Email: fubay@yeditepe.edu.tr) : Optical spectroscopic study of rubrene nanocrystals. Asian J Spectrosc 2009, 13(4), 95-9.

Rubrene nanocystal is a red colored polycyclic aromatic hydrocarbon. It exhibit prompt fluorescence lifetime of 16±1ns, close to the natural lifetime and B-type of delayed fluorescence of 48±5 ns. Rubrene excited states can act as quenchers for the fluorescence. Increasing the laser power leads to a saturation of fluorescence and a reduction of its lifetime. Raman Stokes shift was observed at 670 nm in the fluorescence spectrum. The fluorescence emission spectrum of rubrene molecule in solution mirrors the shape of the absorption spectrum regardless of the excitation frequency.

4 illus, 21 ref