Government Vytpg Autonomous College

Durg, India

Government Vytpg Autonomous College

Durg, India
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Dubey V.,Bhilai Institute of Technology | Dubey N.V.,Government Vytpg Autonomous College | Dhoble S.J.,Rashtrasant Tukadoji Maharaj Nagpur University | Swart H.C.,University of the Free State
Journal of Materials Science: Materials in Electronics | Year: 2017

This paper reports on the thermoluminescence (TL) properties of Eu3+ doped in two different host matrix phosphors (Y2O3 and YBO3). The phosphors were prepared by a high temperature solid state reaction method. The method is suitable for a large scale production. The samples were characterized by X-ray diffraction and Rietveld refinement. The different concentration of Eu3+ samples were also examined by TL glow curve analysis for UV, β and γ irradiation. The Y2O3 samples showed well resolved broad peaks that covered the temperature range from 50 to 350 °C and the peak temperature was found at 157 °C for the γ irradiation. For the UV irradiated samples a well resolved peak at 121 °C was found for the Y2O3:Eu3+ doped phosphors. The β irradiated samples showed a resolved peak at 182 °C. A different behaviour was observed for the YBO3:Eu3+ doped phosphors which showed both higher temperature peaks and lower temperature peaks for UV, β and γ irradiation. Here UV irradiated sample showed the formation of shallow trap (surface trapping) and the γ irradiated sample showed the formation of deep trapping. The estimation of the trap formation was evaluated by the calculation of the trapping parameters. The trapping parameters such as activation energy, order of kinetics and frequency factor were calculated by the peak shape method using the computerized glow curve deconvolution technique. Here most of the peak showed second order of kinetics. The effect of γ, β and UV dose exposure on the TL studies was also examined and it showed a linear response with dose which indicated that the samples might be useful for TL dosimetry. The possible mechanics and information about traps formation are presented in detail. © 2017 Springer Science+Business Media New York

Hou G.,Peking University | Wang Y.,Peking University | Hari K.R.,Government Vytpg Autonomous College
Journal of Geodynamics | Year: 2010

The transmission of the tectonic regime from the Paleo-Asian Ocean to the Pacific Ocean during Mesozoic era was reconstructed using the modeling of Late Triassic (T3) and Late Jurassic (J3) stress fields employing two dimensional linear finite element models (2-D FEM). The model at T3 proposes that Qinling-Dabie-Sulu orogens coevally collided and the model J3 proposes that Subei block continued to collide with the North China block along the Sulu orogen while the collision of the Qinling-Dabie orogen was terminated. The stress fields at T3 and J3 during the two episodes were calculated based on mechanical conditions under different deviatoric stresses acting along the boundaries of the North China craton by elastic finite modeling. The transmission between two episodes of stress fields resulted from Qinling-Dabie-Sulu collision between North China and South China in the Late Triassic period, and from continued collision between the Subei block and North China by the NW-trending movement of Izanagi plate during Late Jurassic. The results from modeling of the Mesozoic stress fields of the North China suggest that late Jurassic was the key transmission period of the tectonic regime of the North China block when large scale thrusting triggered the subsequent destruction of the North China craton. © 2009 Elsevier Ltd.

Dubey V.,Bhilai Institute of Technology | Dubey V.,National Institute of Technology Raipur | Agrawal S.,National Institute of Technology Raipur | Kaur J.,Government Vytpg Autonomous College
Optik | Year: 2015

The present paper reports the synthesis and characterization photoluminescence and thermolumi-nescence studies of Gd3+doped Y2O3phosphors. The effect of variable concentration of europium onphotoluminescence (PL) and thermoluminescence (TL) behavior are also studied. The samples were pre-pared by solid state synthesis technique which is suitable for large scale production of phosphors. Thestarting materials used for sample preparation are ZrO2and Gd2O3and CaF2used as a flux. The preparedsample was characterized by X-ray diffraction technique (XRD). The surface morphology of preparedphosphor was determined by field emission gun scanning electron microscopy (FEGSEM) technique. Thediffraction pattern was measured by transmission electron microscopy (TEM) with selected area diffrac-tion pattern. All prepared phosphor with variable concentration of Gd3+(0.2-2 mol%) was studied byphotoluminescence analysis it is found that the excitation spectra of prepared phosphor shows broadexcitation centered at 249 and 254 nm with few shoulder weak peaks at 275, 308 and 315 nm. The exci-tation spectra with variable concentration of Gd3+show strong peaks at 613 nm for 254 nm excitation.For 275 nm excitation strong peaks found at 468, 567, 578 and 608 nm. For recording TL glow curve everytime 2 mg phosphor was irradiated by UV 254 nm source and fixed the heating rate at 6.7°C s-1. Sam-ple shows well resolved peak at 97°C for 2 mol% of Gd3+. Trapping parameters are calculated for everyrecorded glow curve. © 2014 Elsevier GmbH. All rights reserved.

Parakudyil A.S.,Government Vytpg Autonomous College | Pillai A.K.,Government Vytpg Autonomous College | Mathew S.B.,Government Vytpg Autonomous College
Analytical Methods | Year: 2011

A simple, sensitive, and rapid spectrophotometric method is proposed for the determination of the trace amount of thallium. The method is based on the oxidation of rhodamine B hydrazide by thallium(I) in acidic medium to give a pinkish violet radical cation, having a maximum absorption at 565 nm. The sensitivity of the method was found to increase when performed in micellar medium. Beer's law is valid over the concentration range of 0.005 mg mL -1 to 6.4 mg mL-1 with molar absorptivity and Sandell's sensitivity of 6.305× 10-4 L mol-1 cm-1 and 0.008 mg cm-1 respectively. The tolerance limits for interfering ions are discussed. All variables were studied in order to optimize the reaction conditions. The validity of the method was checked by its simultaneous determination in synthetic samples. © 2011 The Royal Society of Chemistry.

Hari K.R.,Government Vytpg Autonomous College | Chalapathi Rao N.V.,Banaras Hindu University | Swarnkar V.,Government Vytpg Autonomous College
Journal of the Geological Society of India | Year: 2011

We report the occurrence of orthopyroxene gabbro from the Phenai Mata Igneous Complex (containing thoeliitic and alkaline rocks) that occur within Deccan Traps. The P-T calculations based on two pyroxene thermometry vary from 8.5±1.0 kbar and 963±39 °C. These gabbroic rocks exhibit high Mg# (0.67 to 0.71). But their primary magma signature can be negated due to their high SiO 2 (> 50 wt %), low Ni (32-35 ppm) and Cr (105-182 ppm) contents. Further, simple fractional crystallization was not responsible for the modification of the magma. Modeling carried out using trace element concentrations revealed that concurrent assimilation and fractional crystallization (AFC) was responsible for the genesis of these rocks. Small pods of magma could have accumulated in the crustal portions and concurrent assimilation and fractional crystallization have taken place in the generation of gabbro and orthopyroxene gabbro in the present study area. © 2011 Geological Society of India.

Singh A.K.,Government Vytpg Autonomous College | Thool G.S.,Government Vytpg Autonomous College | Deo S.R.,Government Vytpg Autonomous College | Singh R.S.,Government D T College | Gupta A.,Indian Institute of Technology Kanpur
Research on Chemical Intermediates | Year: 2012

Zinc oxide thin films have been deposited on glass substrates by the chemical bath deposition method; a surfactant, cetyltrimethylammonium bromide (CTAB); was used as capping agent. The films were annealed at two different temperatures: 200 and 300 °C. The structural features were investigated by X-ray diffraction analysis which exhibited hexagonal wurtzite structures along with c-axis orientations. Crystallite size was estimated and found to be around 33-41 nm. The effect of post-deposition thermal annealing on the morphological and optical properties has been investigated by scanning electron microscopy and photoluminescence spectra at room temperature. The band gap energies of uncapped and CTAB-capped ZnO films were found to be 3.28 and 3.48 eV, respectively. © Springer Science+Business Media B.V. 2012.

Shukla S.,Government VYTPG Autonomous College | Kashyap A.,Government VYTPG Autonomous College
Research Journal of Pharmaceutical, Biological and Chemical Sciences | Year: 2014

A new ternary complexes of Cu(II) with amino acid have been prepared. In this proline taken as common ligand, where as glycine and lysine taken as secondary ligands. These have been characterized on the basis of elemental analysis, melting point, magnetic susceptibility and electronic spectra. The result of elemental analysis suggest that the molecular formula of the complexes is Cu(AB) 2H2O type, spectral studies suggest that this complexes have octahedral geometry since single band is observed in the electronic spectra trans-geometry is proved.

Tiwari N.,Government Vytpg Autonomous College | Asthana A.,Government Vytpg Autonomous College | Upadhyay K.,Government Vytpg Autonomous College
Research on Chemical Intermediates | Year: 2013

A simple sensitive extractive spectrophotometric method for determination of trichloroethylene is proposed. Trichloroethylene is treated with pyridine to form glutaconic aldehyde by heterolytic cleavage of the pyridine ring. Glutaconic aldehyde is further coupled with 4-aminoacetanilide to form an orange-red dye which is extractable in 3-methyl-1-butanol. The extracted dye shows absorption maximum at 520 nm. The system obeys Beer's law in the range of 0.05-0.8 μg mL-1. Important analytical parameters such as time, temperature, reagent concentration, acidity etc. have been optimized for complete colour reaction. Sandell's sensitivity and molar absorptivity for the system were found to be 0.001 μg cm-2 and 1.2 × 10 5 L mol-1 cm-1, respectively. The proposed method is satisfactorily applied to micro-level determination of trichloroethylene in various environmental and biological samples. © 2012 Springer Science+Business Media Dordrecht.

Upadhyay K.,Government Vytpg Autonomous College | Asthana A.,Government Vytpg Autonomous College | Tiwari N.,Government Vytpg Autonomous College | Mathew S.B.,Government Vytpg Autonomous College
Research on Chemical Intermediates | Year: 2013

A simple and sensitive spectrophotometric method for the determination of nimesulide in bulk, in pharmaceutical dosage form, and in biological fluids was developed. The method is based on the reduction of the nitro group of nimesulide by zinc and hydrochloric acid followed by diazotization, and coupling with orcinol in basic medium to form a stable chromophore, which absorbs at 465 nm. The method showed a good linearity in the range 0.4-4.0 μg mL-1. Partial least square modeling as a powerful multivariate statistical tool is also applied, compiled, and compared for determination of nimesulide. The experimental matrix for the partial least square calibration method was designed with 24 samples. The cross-validation was used for selecting the number of factors. The root mean square error prediction (RMSEP) and the relative error of prediction (REP %) were 0.089 and 3.95, respectively. The developed method is free from the interference of common excipients used in pharmaceutical dosages. The method was also used for the determination of nimesulide in pharmaceutical dosages as well as in human serum and urine samples. © 2012 Springer Science+Business Media Dordrecht.

Sar S.K.,Bhilai Institute of Technology | Rathod N.,Government VYTPG Autonomous College | Pandey P.K.,Bhilai Institute of Technology
International Journal of Chemical Kinetics | Year: 2010

Pseudo-first-order rate constants for the nucleophilic debenzoylation reaction of ρ-nitrophenyl benzoate with, various hydroxamate ions [RC = ONHO -] were investigated in aqueous cationic micellar media at pH 7.8 and 27°C. The kinetic rate data of the reaction revealed that the nucleophilic reactivity sequence of these hydroxamate ions is generally benzohydroxamic acid > salicylhydroxamic acid > acetohydroxamic acid. The k obs value increases upon addition of cationic surfactants to the reaction medium involving interfacial ion exchange between bulk aqueous media and micellar pseudophase. The effect of surfactant head and tail group is discussed. © 2009 Wiley Periodicals, Inc.

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