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Singh M.,Amity University | Singh M.,Guru Jambheshwar University of Science and Technology | Pal Singh V.,Singhania University | Sangwan A.,D. C. R. University of Science and Technology | And 2 more authors.
Journal of Nonlinear Optical Physics and Materials | Year: 2014

By considering the hydrodynamic model of semiconductor-plasmas, an analytical investigation is performed to study the influence of Szigeti effective charge (qs) on coherent Raman scattering (CRS) of laser radiation in a transversely magnetized direct gap semiconductor arising from electron density perturbations and molecular vibrations of the medium both produced at the transverse optical phonon frequency. Assuming that the origin of CRS lies in the third-order susceptibility of the medium, an expression is obtained for Raman gain coefficient (gR). Numerical estimates are made for a representative n-type InSb crystal duly shined by pulsed 10.6 μm CO2 laser. The threshold field (E0th) for inciting CRS is identified. The dependence of gR on pump field strength E 0, externally applied magnetic field (in terms of electron cyclotron frequency ωc) and doping concentration (in terms of plasma frequency ωp) is reported for both cases viz., qs = 0 and qs ≠ 0. In absence of qs, the results are found to be well in agreement with available literature. © 2014 World Scientific Publishing Company. Source


Kumar R.,Kurukshetra University | Meglani A.,Chaudhary Devilal University | Garg S.,P.A. College
Materials Physics and Mechanics | Year: 2013

The present study is concerned with the reflection and transmission of plane waves at an imperfect interface between two different fluid saturated porous half spaces. The expression for the reflection and transmission coefficients which are the ratios of the amplitude of reflected and transmitted waves to the amplitude of incident waves are obtained for an imperfect boundary and deduced for normal stiffness, transverse stiffness. The variations of amplitude ratios with angle of incidence are depicted graphically. A particular case of reflection at the free surface in fluid saturated porous half spaces has been deduced and discussed. A special case of interest has also been deduced from the present investigation. It is found that amplitude ratios of the reflected and transmitted waves are affected by the stiffness of the media. © 2013, Institute of Problems of Mechanical Engineering. Source


Bharti V.,Sudan University of Science and Technology | Vasudeva N.,Sudan University of Science and Technology | Duhan J.S.,Chaudhary Devilal University
International Food Research Journal | Year: 2013

The use of food preservatives to prevent spoilage of the product during transportation and shelf life by food manufacturers is common. Artificial preservatives added may prevent the food but they may be carcinogenic and may harm the consumer's health. In food producing animals also, due to misuse of antimicrobials, antibiotic resistance have been developed which is affecting food industry. The present study was done to find out Oreganum vulgare, the most common food herb's antimicrobial potential against food poisoning organisms. The volatile oil was analysed by GC-MS and chloroform extract was fractionated into phenolic and non-phenolic part. The fractions and volatile oil were used alone and in combination with standard antimicrobials to evaluate the interaction effect. Volatile oil consisted of mainly Carvacrol (86.5%), {Thorn}-cymene (7.2%) followed by bornyl acetate. The Minimum Inhibitory Concentration (MIC) was found to be lowest for volatile oil followed by phenolic fraction when used alone and both in combination against Shigella flexneri, Aspergillus flavus and Salmonella enterica ser. Typhi. Synergism was shown by volatile oil with a FICI of 0.265, 0.187, 0.280 when combined with ciprofloxacin and fluconazole respectively against Shigella flexneri, Salmonella enterica ser. Typhi and Aspergillus flavus. Obtained data suggest the potential use of volatile oil and phenolic fraction of chloroform extract as along with standard antimicrobials as more effective combination with lesser side effects. The demonstrated antimicrobial activity of phenolic fraction and volatile oil when used alone suggests their use in food industry as preservatives without any toxicity. The interaction studies data with standard antimicrobials indicates the use of these combinations to infected food producing animals and humans; hence may solve the problem of antibiotic resistance in future. © 2008 IFRJ. Source


Kumar S.,Chaudhary Devilal University | Chakarvarti S.K.,Manav Rachna International University
AIP Conference Proceedings | Year: 2011

Copper nanowires have been synthesized successfully using template assisted electrodeposition technique. Commercial polycarbonate membrane (Whatman, Japan) having pore diameter 100 nm, thickness 10 μm and pore density 107 pores/cm2 was used as template. Scanning electron microscopy and X-ray diffraction techniques were used to characterize the synthesized copper nanowires. XRD and SEM results reveal that polycrystalline copper nanowires were obtained with fcc lattice structure having diameter equal to the diameter of the template used. © 2011 American Institute of Physics. Source


Sanghi S.,Guru Jambheshwar University of Science and Technology | Duhan S.,Chaudhary Devilal University | Agarwal A.,Guru Jambheshwar University of Science and Technology | Aghamkar P.,Chaudhary Devilal University
Physica B: Condensed Matter | Year: 2010

Iron calcium bismuthate glasses having composition 0.05Fe2O 3·0.95{xCaO·(100-x)Bi2O3} (x=30, 35 and 40 mol%) were prepared using normal melt quench technique. Complex impedance spectra of these glasses have been recorded in the temperature range 523633 K and in the frequency range 20 Hz1 MHz. The complex impedance data have been analyzed using the conductivity as well as electric modulus formalisms. The dc conductivity increases and activation energy decreases when CaO content increases. The modification of the glass network, due to the increase in CaO content, is responsible for the increase in conductivity. The frequency dependence of ac conductivity is found to obey the Jonscher power law. At low frequencies, dispersion was investigated in terms of dielectric loss. Significant changes in the values of the non exponential parameter (β) and the power law exponent (s) of the ac electrical properties have been observed as a function of CaO in the present glasses. A single 'master curve' for the normalized plots of all the modulus isotherms observed for a given composition indicates that the conductivity relaxation is temperature independent. The overlapping of the normalized peaks corresponding to impedance (Z″) and electric modulus (M″) suggests the same thermal activation energy for conduction and relaxation, which further suggests a single mechanism for the dynamic processes in the present glasses. © 2010 Elsevier B.V. All rights reserved. Source

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