R. Somashekar

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Eswar Prasad Korilimilli

Mahindra Ecole Centrale

Vadim Silberschmidt

Loughborough University

Virginie Boucher

CSIC (Consejo Superior de Investigaciones Científicas-Spanish National Research Council)

José Luis Rodríguez-López

Instituto Potosino de Investigacion Cientifica y Tecnologica

DR.GIRISH JOSHI

VIT University

Ali Samer

Universiti Teknologi PETRONAS

Maderas. Ciencia y Tecnologia

Universidad del Bio-bio

Richard Wolbers

Winterthur Program at the University of Delaware

Pamies Teixeira

Universidade Nova de Lisboa

Gerhard Welsch

Case Western Reserve University

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Papers by R. Somashekar

Effect of microwave radiation on Jayadhar cotton fibers: WAXS studies

ABSTRACT Thermal effect in the form of micro wave energy on Jayadhar cotton fiber has been invest... more ABSTRACT Thermal effect in the form of micro wave energy on Jayadhar cotton fiber has been investigated. Microstructural parameters have been estimated using wide angle x-ray scattering (WAXS) data and line profile analysis program developed by us. Physical properties like tensile strength are correlated with X-ray results. We observe that the microwave radiation do affect significantly many parameters and we have suggested a multivariate analysis of these parameters to arrive at a significant result.

Microstructural Parameters of HPMC/PVP Polymer Blends Using Wide Angle X-Ray Techniqu

by R. Somashekar and Thippaiah Demappa

Hydroxypropylemethylecellulose (HPMC) and Polyvinylpyrrolidone (PVP) polymer virgin and blend fil... more Hydroxypropylemethylecellulose (HPMC) and Polyvinylpyrrolidone (PVP) polymer virgin and blend films were prepared and investigated using wide angle X-ray scattering method. Microstructural parameters like lattice strain (g %), the crystallite size for individual the Bragg's reflection (hkl) have been computed using line profile analysis and hence by whole pattern fitting method. The X-ray diffraction study reveals that the blending of PVP decreases the crystallanity of HPMC up to 5:4 concentration and then increases. Measured tensile strength decreases, Young's Modulus decreases, and % elongation increases as the concentration of PVP increases. The surface morphology investigated using scanning electron microscope, shows that the two polymers were miscible in all concentration range.

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Physical and thermal properties of 8 MeV electron beam irradiated HPMC polymer films

by Thippaiah Demappa and R. Somashekar

Microstructural modification in hydroxypropyl methylcellulose (HPMC) polymer films induced by ele... more Microstructural modification in hydroxypropyl methylcellulose (HPMC) polymer films induced by electron irradiation is studied. Irradiation was performed in air at room temperature using a 8 MeV electron accelerator at doses of 25, 50, 75 and 100 kGy. Irradiation can be used to crosslink or degrade the desired component or to fix the polymer morphology. Changes in microstructural parameters, crystallinity and thermal properties in virgin and irradiated HPMC films have been studied using wide angle X-ray scattering data and differential scanning calorimetry. The heat of fusion and the degree of crystallinity are found to be highest for unirradiated HPMC and the crystallite size is larger in virgin HPMC films.

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Structure-property relation in HPMC polymer films plasticized with Sorbitol

AIP Conference Proceedings, 2013

ABSTRACT A correlation study on physical and mechanical properties of Hydroxy propyl-methylcellul... more ABSTRACT A correlation study on physical and mechanical properties of Hydroxy propyl-methylcellulose (HPMC) polymer films plasticized with different weight ratio of Sorbitol, prepared using solution casting method, was carried out using wide angle X-ray technique and universal testing machine. It is found that the crystallanity decreases as the concentration of Sorbitol increases up to a certain concentration and there afterwards increases. Measured Physical Properties like tensile strength decreases and elongation (%) increases indicating increase in the flexibility of the films. These observations confirm the correlation between microstructal parameters and mechanical properties of films. These films are suitable for packaging food products.

Rate of recovery of long periodicity in stretched muscle specimen using SAXS data

An expression for scattered X-ray intensity from one-dimensional Hosemann's linear paracrysta... more An expression for scattered X-ray intensity from one-dimensional Hosemann's linear paracrystalline model consisting of alternate crystalline and amorphous regions has been reduced to easily computational form by employing exponential distribution function here. We have used this theoretical approach to analyse the Iwamoto et al's SAXS data of stretched frog muscle fibers obtained at every millisec from the released state and hence to compute the long periodicity of myosin along with the rate of recovery of this muscle fiber for the first time. We also find that the changes are linear in nature. The width of the crystalline phase length distribution does not vary with the released time indicating the changes are within the layer wherein the chain unfolds at the rate of 1.15 angstrom/ms in myosin fibers. Fraction of amorphous component which we have computed on the basis of paracrystalline model has been reported. The parameters which are related to nucleation growth rates, growth geometry and type of nucleation have been computed using Avrami equation. These results have been compared with the values observed for polymers.

Small angle X-ray scattering patterns in silk fibres

Characterization of white and red teff grains using X-ray technique

by Kiros Hagos, R. Somashekar, and Jayanth Channagiri

This study presents X-ray studies to investigate effect of microwave radiation and solvent treatm... more

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Variation of Crystallite Ellipsoids for Varieties of Cotton Fibers Using Whole Powder Pattern Fitting Technique

By using wide angle x-ray scattering (WAXS) technique, we have characterized varieties of cotton ... more By using wide angle x-ray scattering (WAXS) technique, we have characterized varieties of cotton fibers. The microstructural parameters like crystallite size and lattice strain (g in %) have been computed for varieties of cotton fibers using whole powder pattern fitting technique developed by us. It is observed that the volume of the crystallite shape ellipsoid is more in mcu-5 compared to the other varieties of cotton fibers. 1. INTRODUCTION One of the most widely used natural fibers is cotton fiber and also an important material used as textile fiber in the world.Cotton fiber is a member of Hibiscus family and botanical name Gossypiumhirsutum or barbadense[1]. Cotton fibers will be cultivated in and around southern states of India such as Karnataka, Andhra Pradesh and Maharashtra. It is a major crop for several countries[2]. Cotton fiber is made up of pure fibrous cellulose. Cellulose is a high polymer consisting of units of anhydro-D-glucopyranose linked through β-1-4 linkages wi...

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Preparation and Characterization of Mulbery Silk Fibroin Films

The silk films were prepared by dissolving degummed Bombyx mori raw silk fibers in LiBr salt solu... more The silk films were prepared by dissolving degummed Bombyx mori raw silk fibers in LiBr salt solution using double distilled water as a solvent and subjecting the solution to dialysis using cellulose tube. These films may be of some use in treating burn injuries. We have characterized these films using X-rays and other physical methods to obtain information about the structure-property relation. We have also compared the parameters of silk films with that of silk fibers.

Radial distribution studies on water soluble polymers using XRD line profile data

ABSTRACT Pair correlation and line profile analyses of X-ray data obtained for some man-made poly... more ABSTRACT Pair correlation and line profile analyses of X-ray data obtained for some man-made polymers have been carried out in this report. Results obtained show that the pair correlation is pronounced in the region of 2Å and dies away for regions greater than 10Å in general for all the samples in the neighborhood of the point where X-rays are incident on the sample. Complementary to this study, line profile analysis shows that the crystallite size and strain obtained from Williamson-Hall plot method in these polymers do change significantly. This information is in no way connected to the results of pair correlation study.

Electrical conductivity and microcrystalline parameter in Co–Zn ferrites

Materials Research Innovations, 2011

A series of samples of the system Co 12x Zn x Fe 2 O 4 (for x50?0, 0?2, 0?4, 0?6 and 1?0) were pr... more A series of samples of the system Co 12x Zn x Fe 2 O 4 (for x50?0, 0?2, 0?4, 0?6 and 1?0) were prepared by usual ceramic technique. These prepared samples were examined using X-ray powder pattern, which confirms the presence of a spinel structure. The authors have also carried out line profile analysis of individual Bragg reflections observed in these ferrites, which shows variation in the cell parameter. Further electrical conductivity measurements of these ferrites were carried out as a function of temperature. The observed values of the electrical conductivity have been explained on the basis of Verwey's hopping mechanism. The activation energy was found to decrease with increasing Zn content. In addition, its variations for varying concentrations of Zn in Co are interpreted in terms of microstructural parameters.

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Polymeric degradation of water soluble chitosan/HPMC films using WAXS data

Materials Research Innovations, 2012

Films of cationic chitosan and non-ionic hydroxypropyl methyl cellulose (HPMC) have been prepared... more Films of cationic chitosan and non-ionic hydroxypropyl methyl cellulose (HPMC) have been prepared by solvent casting method, using glycerol as a plasticiser, from aqueous lactic acid medium. Here, an attempt is made to compare the degradation effect of neutral HPMC and chitosan on water uptake and flexibility in terms of microstructural parameters obtained from X-ray line profile analysis. The intension of this study is to investigate properties for the potential use of chitosan/HPMC films to improve flexibility for packaging, solubility of drug, drug release and biodegradability. Fractured surfaces of the films were examined through wide angle X-ray diffraction and the intensity profiles were used to determine the microstructural parameters. Chitosan and HPMC films have more water retentiveness property compared to other blends studied here.

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Photocatalytic treatment of municipal wastewater using modified neodymium doped TiO2hybrid nanoparticles

Journal of Environmental Science and Health, Part A, 2010

Photocatalytic degradation of municipal wastewater was investigated using reagent grade TiO(2) an... more Photocatalytic degradation of municipal wastewater was investigated using reagent grade TiO(2) and modified neodymium doped TiO(2) hybrid nanoparticles. For the first time, surface modification of Nd(3 +) doped TiO(2) hybrid nanoparticles were carried out with n-butylamine as surface modifier under mild hydrothermal conditions. The modified nanoparticles obtained were characterized by Powder XRD, FTIR, DLS, TEM, BET surface area, zeta potential and UV-Vis Spectroscopy. The characterization results indicated better morphology, particle size distribution and low agglomeration of the nanoparticles synthesized. It was found that photodegradation of wastewater using surface modified neodymium doped TiO(2) nanoparticles was more compared to pure TiO(2), which can be attributed to the doping and modification with n-butylamine.

Synthesis of ZnO/MgO Nanocomposites by Electrochemical Method for Photocatalytic Degradation Kinetics of Eosin Yellow Dye

ZnO/MgO has been synthesized by electrochemical method and characterized by UV-Visible spectrosco... more ZnO/MgO has been synthesized by electrochemical method and characterized by UV-Visible spectroscopy, IR spectroscopy, SEM, XRD, PALS and density measurement data. The UV-Visible spectroscopy results reveals that the band gap energy of ZnO/MgO nanocomposite to be 3.9 eV. The XRD results show that the crystallite size to be 17.55 nm calculated using Williamson-Hall plot. The PALS measurements reveal that the ZnO/MgO nanocoposites consists of more defects and vacancies than ZnO. An improvement in photocatalytic degradation of Eosin Yellow (EY) dye in comparison to commercially available pure ZnO was observed. The photodegradation efficiency for ZnO/MgO and ZnO were found to be 84.82% and 27.97% respectively. The enhancement in photocatalytic activity of ZnO/MgO nanocomposite was because of the highly hygroscopic and nanoporous MgO. The MgO layer contains more H2O and hydroxyl groups and offers a larger surface area.

Lamellar Mesophase(G) in Mixtures of Stearyl Alcohol and Dimethyl Sulfoxide

Molecular Crystals and Liquid Crystals, 1985

Using x-ray, DSC and Optical studies, the mixtures of stearyl alcohol and dimethyl sulfoxide were... more

The viscosity of cholesteryl oleyl carbonate

The viscosity of liq.-crystal cholesteryl oleyl carbonate at 19-41Â° was measured with a concentr... more

Microstructural Parameters of 8 MeV Electron Irradiated Poly (vinyl alcohol) Polymer Films

AIP Conference Proceedings, 2011

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Effects of high energy electrons on physical and tensile properties of non-mulberry silk fibers

Fibers and Polymers, 2013

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