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Nāgpur, India

Malankar H.,Visvesvaraya National Institute of Technology | Umare S.S.,Visvesvaraya National Institute of Technology | Singh K.,Sant Gadge Baba Amravati University | Sharma M.,SFS College
Journal of Solid State Electrochemistry | Year: 2010

γ-MnO 2, synthesized chemically from local manganese ore, was subjected to physicochemical studies. X-ray diffraction, Fourier transform infrared spectroscopy, surface area measurement, thermogravimetry/differential thermal analysis, scanning electron microscopy, and chemical analyses were used to determine the structural and chemical disorder present in the samples. The electrochemical activity in alkaline medium was evaluated by recording discharge profile at constant current and constant load condition. The charge-discharge profile in 9 M KOH was studied by cyclic voltammetry. The samples were found to be "type III" γ-MnO 2 with high degree of microtwinning defect (T w). The De Wolff disorder was in the range 0.21


The proton-ligand stability constant of ligand (2,3-dibromo-1-(5-chloro-2-hydroxyphenyl)-3-phenyl-propan-1-one) and metal-ligand stability constants with Ni(II) metal ions were investigated in the presence of 0.02, 0.04, 0.06, 0.08 and 0.1 mol L-1 KNO3 pH metrically at 28 °C. The formations of binary 1:1, 1:2 ligand-Ni(II) complexes were reported. The data obtained was utilized to estimate the thermodynamic stability constants (pK° and log K°) for ligand and its complex with Ni(II) ions at zero ionic strength to know the exact nature of the complexation equilibria. The different possible reactions and expected values of ΔZ2 for corresponding dissociation or association equilibria are determined. Source

Hiwase V.V.,Institute of Science | Hiwase V.V.,Commerce and Science College | Kalambe A.B.,Institute of Science | Khedkar K.M.,Institute of Science | And 2 more authors.
E-Journal of Chemistry | Year: 2010

The terpolymeric resins were prepared by base catalyzed polycondensation of p-hydroxybenzaldehyde, resorcinol and formaldehyde. Resin obtained by molar monomer composition, p-hydroxybenzaldehyde: resorcinol: formaldehyde as 1:1:3 was abbreviated as PHBRF-I and that prepared by 1:2:4 composition was abbreviated as PHBRF-II. These resins were characterized by physicochemical methods such as elementa analysis, UV-Vis, IR and NMR. ion-exchange study was carried out with Cu2+, Zn2+, Ni2+, Co2+, Pb2+ & Cd2+ by batch equilibrium method. The rate of metal ion uptake by PHBRF-II terpolymeric resin was higher than that of PHBRF-I. Effect of pH and electrolytes under specified condition were also studied. The terpolymeric resins show high selectivity for Cu2+, Zn2+ and Co2+ as compared to Ni2+, Pb2+, and Cd2+. Source

Durugkar P.D.,SFS College | Ghulghule J.R.,Y.C.C.E. | Katpatal A.G.,VNIT
Ferroelectrics | Year: 2011

Four compositions pure (KN), 1 wt% Sm (KND-1), 2 wt% Sm (KND-2) and 1 wt% Sm + 1 wt% Sn (KND-3) potassium niobate were grown as single crystals by controlled cooling of the melt. Electrical conductivity as a function of temperature was studied from room temperature up to 500°C for these compositions. At room temperature the electrical conductivity has increased due to Sm as well as (Sm & Sn) doping. Crystals show increase in conductivity with temperature. Both pure and doped compositions show an anomalous behaviour with a small hump around their respective transition temperatures except KND-2. The conductivity in pure and doped potassium niobate is a complex phenomenon namely due to electronic contribution; extrinsic impurity; presence of impurity defects; vacancies created due to oxygen deficiency as well as doping and polaron hopping. Copyright © Taylor & Francis Group, LLC. Source

Gupta M.M.,University of Delhi | Naqvi N.S.,SFS College | Singh V.K.,University of Delhi
Sydowia | Year: 2014

During the last few years there have been revolutionary changes in understanding of arbuscular mycorrhizal (AM) fungi distribution, conservation and prospecting using computational databases and platforms. In the present study a searchable biodiversity database available at http://amfungi.aurobindo.du.ac.in and www.amfungi.in is presented using MS access and visual basic applications (VBA). A consolidated region-wise distribution checklist of 148 species of AM fungi belonging to 21 genera of the phylum Glomeromycota is developed, which can be searched either species-wise or state-wise to retrieve information about latest consensus classification, type specimen description, apart from occurrence and abundance. We report Funneliformis mosseae to be the most widely distributed species of Glomeromycota in India, present in the largest number of states which is in dissent with earlier reports of Glomus fasciculatum and Glomus macrocarpum as the most widely distributed species. The genus Glomus is represented by the highest number of species followed by Acaulospora and Scutellospora. The states falling in the Western Ghats region, i.e. Karnataka, Goa and Maharashtra, contain more than 68.9 % of total AM fungal species reported from India. Many important states of India especially Himachal Pradesh, North Eastern India which covers the region of Himalayas and Aravallis remain less represented. We hope that the checklist serves as a quick reference for knowing which Glomeromycota are expected at any Indian location and can be further used to fill gaps in world distribution maps of AMF apart from providing latest classification and quick links to the availability of monospore cultures and original species description. Source

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