Raibareli, India
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Sharma R.,Feroze Gandhi Institute of Engineering and Technology | Dwivedi S.,Feroze Gandhi College | Sharma Y.,Feroze Gandhi College
International Journal of Hydrogen Energy | Year: 2015

Ternary intermetallic YPd3 is known to exhibit superior hydrogen storage capacity compared to pure palladium. To understand the characteristics of YPd3 on hydrogenation, the ground state electronic and dynamical properties were computed by two computational methods, the full potential linearized plane wave and projector augmented wave methods within the density functional theory. Hydrogen can be inserted in YPd3 at various octahedral sites, giving rise to model structures YPd3H and YPd3H4 which retain the L12 crystal structure. The calculated energy bands confirm the metallic nature of YPd3 and also exhibit greater dispersion of bands with increase in hydrogen content. Large variations in the optical constants such as transmittance is observed (by ∼40% in the violet region) with insertion of hydrogen, YPd3 may have thus have applications as a sensing device for monitoring hydrogen for using hydrogen safely. The electronic component γ obtained from the temperature dependent specific heats, is related to the density of states at the Fermi level which may be co-related to instability of hydrides. The modes at Γ-point in YPd3H and at X and M-points in YPd3H4 give rise to high peaks in the imaginary frequency regime which could drive the dynamical instabilities. From the formation energies and phonon modes it is found that the monohydride YPd3H is more stable, thus occupation of the octahedral sites at 2Y4Pd by hydrogen atoms results in greater dynamic instability in YPd3. © 2014 Hydrogen Energy Publications, LLC.


Root-rot caused by Rhizoctonia solani is a destructive disease of French bean (Phaseolus vulgaris) in the northern plains of India. A randomized block design field experiment was laid out in loam soil containing low organic carbon, nitrogen and medium available phosphorus to evaluate the disease controlling potential of soil inhabiting arbuscular mycorrhizal fungi (AMF) and bacteria. Plants treated with AMF either alone or in combination with Pseudomonas fluorescens, could endure the root-rot incidence under field conditions and produced higher pod yield. Combined inoculation of AMF + P. fluorescens was more effective for controlling the disease as well as increasing the yield. Addition of mustard oil cake to dual inoculation i.e. AMF + P. fluorescens was found highly effective. AMF + p dose chemical phosphorus also improved pod yield and 100-seed weight even in R. solani infected plants. Mixed inoculations along with mustard oil cake were found best treatments for root-rot disease control management. © 2011 Elsevier Masson SAS.


Bhadauria T.,Feroze Gandhi College | Kumar P.,Feroze Gandhi College | Kumar R.,Feroze Gandhi College | Maikhuri R.K.,Gb Pant Institute Of Himalayan Environment And Development | And 2 more authors.
Applied Soil Ecology | Year: 2012

Scientific knowledge of belowground biodiversity in the Himalaya, a biodiversity hotspot, is scarce. The aim of this study was to investigate density and biomass of earthworm populations and soil properties (texture, bulk density, organic C, total N and pH) in the full range of land use types viz., moderately degraded natural forests (MDNF), highly degraded natural forests (HDNF), rehabilitated forest land (RFL), traditional pure crop system (TPCS), traditional agroforestry system (TAS), abandoned agricultural land (AAL) and rehabilitated agricultural land (RAL) in a village landscape in Central Himalayan region of India. Of the 8 species present in the landscape, Amynthas alexandri and Metaphire anomala were the most widely distributed taxa, with the former absent only in RAL and the latter only in HDNF, while Bimastos parvus and Perionyx excavatus were confined to MDNF. TPCS and TAFS harboured the same species. AAL had only one (endogeics) and RAL all the three functional groups (endogeics, epigeics and anecics). All species except B. parvus showed a strong effect of season on population size, with the highest abundance and biomass values observed during rainy season. Only D. nepalensis and M. birmanica were a little bit abundant during dry season in TAFS. In the peak month of September, total density showed a trend of TAFS>TPCS>MDNF>RAL>AAL>RFL>HDNF (147, 132, 63, 27, 14, 8 and 5 individuals m -2, respectively) and biomass of TAFS>TPCS>MDNF>RFL>RAL>AAL>HDNF (266, 199, 51, 24, 21, 16 and 11gm -2, respectively). The study shows that (i) a change from TPCS to TAFS follows a substantial increase in earthworm density/biomass but not in species richness, (ii) TPCS/TAFS and MDNF host equal number of species but different species composition, with the former having much larger abundance than the latter, (iii) conversion of TPCS to AAL and of MDNF to HDNF cause drastic reduction in species richness and soil organic carbon (SOC), (iv) rehabilitation (change from AAL to RAL and HDNF to RFL) only partly recuperates SOC and earthworm fauna over a period of 20 years, (v) native species fail to survive in highly perturbed environment in HDNF and also in recuperating RFL but coexist with exotics in all other land use types, (vi) SOC explained around 60% of the variation in total density/biomass and (vii) heterogeneous landscapes with agriculture-forest mixed land uses are likely to support greater species richness than homogeneous agriculture/forest ones. Huge variability in land use histories, management practices and biophysical conditions warrant more research on spatio-temporal dynamics of earthworm communities and the linkages between belowground biodiversity, aboveground biodiversity and ecosystem functions. © 2011 Elsevier B.V.


Sharma Y.,Feroze Gandhi College | Srivastava P.,Feroze Gandhi College
Indian Journal of Pure and Applied Physics | Year: 2011

Transparent conducting oxides have important applications as optoelectronic devices. First principles calculations have been performed to study the electronic and optical properties of Sc-, Y- and Ti-doped transparent conducting oxide (TCO) material CdO. The dielectric functions, absorption coefficients and transmittance spectra have been computed to study the effect of doping. The density of states have also been investigated to interpret the calculated optical spectra in terms of inter band transitions. The valence electron charge density is plotted to understand the redistribution of charges on introduction of transition metal ions. The electrical conductivity and Hall coefficient have also been calculated. The calculated band gap for pure CdO which is 0.51 eV increases significantly with doping. The band gaps for Sc-, Y- and Ti- doped CdO are 2.67, 2.83 and 2.53 eV, respectively, which are in good agreement with experimental measurements.


Sharma Y.,Feroze Gandhi College | Srivastava P.,Feroze Gandhi College
Optical Materials | Year: 2011

Crystalline arsenic telluride exists in two stable phases. The monoclinic α-phase transforms to rhombohedral β-phase under high pressure. The electronic, optical and transport properties of the two phases has been investigated using full potential linear augmented plane wave (LAPW) + local orbitals (lo) scheme, in the framework of DFT with generalized gradient approximation (GGA). We present the energy bands, density of states and optical properties like the complex dielectric functions and absorption coefficients. From the dynamic dielectric constant, the structural anisotropy for the monoclinic α-phase is clearly observed, whereas the longitudinal and transverse components are almost identical for the β-phase. The optical absorption profiles clearly indicate that β-phase has possibility of greater multiple direct and indirect interband transitions in the infrared and visible regions compared to the α-phase. The rhomohedral phase which has the Bi2Te3 type structure has the possibility of thermoelectric properties, therefore transport properties like electrical and thermal conductivities, Seebeck and Hall coefficients etc. are also calculated. Good agreements are found with the available experimental results. © 2011 Elsevier B.V. All rights reserved.


Srivastava P.,Feroze Gandhi College | Singh Mund H.,University of Rajasthan | Sharma Y.,Feroze Gandhi College
Physica B: Condensed Matter | Year: 2011

The electronic structure of crystalline As2S3 and As2Se3 has been calculated in this paper. We present the energy bands, density of states (DOS) and the Compton profiles using the linear combination of atomic orbitals (LCAO) scheme based on the density functional theory (DFT). From the calculated total and partial density of states it is seen that the lone-pair p-states of sulphur/selenium contribute closest to the Fermi energy level. To interpret the theoretical data on the Compton line shape, we have measured the Compton profiles on a 100 mCi 241Am spectrometer. It is seen that the density functional theory within generalised gradient approximation gives a slightly better agreement with the experimental momentum densities. The nature of chemical bonding in arsenic chalcogenides is studied using Mullikens population analysis and the experimentally measured equal-valence-electron-density profiles; As2S3 is found to be more ionic compared to As2Se3. © 2011 Elsevier B.V.


Sharma R.,Mewar University | Sharma R.,Feroze Gandhi College | Sharma Y.,Feroze Gandhi College
International Journal of Hydrogen Energy | Year: 2015

Considerable attention has recently been given to bimetallic systems such as Cu-Pd alloys as hydrogen storage material. These alloys are attractive alternatives to pure Pd membranes because of their sulphur tolerance and high permeability to hydrogen. The density functional theory based full potential linearized augmented plane wave and projector augmented wave methods have been implemented to understand the phenomenon of hydrogen diffusion in Cu-Pd alloys. The AuCu3 structure of CuPd3 and Cu3Pd allows intercalation of hydrogen atoms in its octahedral sites. The lattice parameters and volume of the unit cell expand on hydrogenation, without phase change. We have studied the formation and stability of hydrides of the ternary alloys. The heats of formation support the hydrogenation of CuPd3 alloy whereas the endothermic reactions indicate that hydrogen will be absorbed in the Cu3Pd alloy at the expense of energy. The phonon dispersion relations of the hydrides of CuPd3 exhibits instability due to the Pd-H bonds which leads to distortion of Pd-octahedra in the unit cell. Softening of acoustic modes is not observed in the Cu3Pd alloy; instead the optical modes due to H-H bonds have very high vibrational frequencies. The permeance of H atoms in the alloy can be quantified from the extent of hybridization between H s-states, Cu and Pd d-states. From the density of states, the movement of the H s-band and centre of d-bands towards the Fermi energy level EF was observed. Both the factors indicated that the monohydride of CuPd3 was most stable. The temperature dependent Hall and Seebeck coefficients reflect the modifications in the electronic structure due to formation of hydrides. At ambient temperatures, the free charges carriers (electrons) are found to increase in the monohydride of Cu3Pd, whereas it decreases in the monohydride of CuPd3. The electronic component of specific heats γ obtained from low temperature specific heats is found to decrease in the hydrides of both the alloys, which implies an increase in the lattice contribution through the electron-phonon coupling. From the optical properties, it is possible to monitor the hydrogen uptake in the alloys by studying the variations in reflectance, absorption coefficients in the visible regions. The electronic and dynamical studies suggest that the alloy with excess Pd has potential applications as hydrogen storage materials. The monohydride of CuPd3 appears to be appropriately stable for applications such as electrode material in rechargeable batteries. © 2015 Hydrogen Energy Publications, LLC.


Sharma R.,Feroze Gandhi Institute of Engineering and Technology | Dwivedi S.,Feroze Gandhi College | Sharma Y.,Feroze Gandhi College
Macromolecular Symposia | Year: 2015

The Cu-Pd alloy, for Pd concentration greater than 50 at% has a distorted FCC structure, while for Pd less than 18 at%, has a L12 type structure. The electronic structure of Cu3Pd and CuPd3, which are the ordered alloys of the Cu-Pd system are investigated by the FP-LAPW method based on the density functional theory. The temperature dependence of the electrical resistivity and Seebeck coefficients has been interpreted in terms of band structures and density of states. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


The effects of inoculation of three arbuscular mycorrhizal (AM) fungi namely, Glomus mosseae, Glomus sinuosum, and Scutellospora erythropa in addition to Pseudomonas fluorescens and treatment with mustard oil cake on root-rot disease of Cyamopsis tetragonoloba L plants caused by Macrophomina phaseolina were evaluated under polyhouse conditions for 2 years. Inoculations of an arbuscular mycorrhizal fungi (AMF) in combination with P. fluorescens and mustard oil cake showed best supporting biocontrol system against the root-rot disease besides increasing the plant height, weight, and yield. The biocontrolling efficiency of dual inoculation (AMF + P. fluorescens) was the second best combination followed by AM plus mustard oil cake. Among the three AM fungi, G. mosseae inoculations showed the best results. Different combined AMF inoculations also altered the concentrations of total soluble sugars, orthodihydric phenols, flavonols, and epicuticular wax contents in host plants. © 2009 Springer-Verlag.


Tiwari C.,Feroze Gandhi College | Sharma R.,Feroze Gandhi Institute Of Engg And Technology | Sharma Y.,Feroze Gandhi College
AIP Conference Proceedings | Year: 2013

In this paper we perform spin polarized calculations and present the electronic structure of Fe doped MoX2 (X=S, Se, Te) using the density functional theory (DFT) with generalized gradient approximation (GGA). The calculated indirect band gaps for semiconducting MoS2, MoSe 2 and MoTe2 are 0.788, 0.864 and 0.68 eV respectively. The dx 2-y2 & dxy states hybridized with p and d states of S and Mo contribute to additional states in the vicinity of Fermi energy. © 2013 American Institute of Physics.

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