Browsing by Author "D. Singh"

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1,3-Dipolar cycloaddition of diphenyl nitrile imine with 4-arylmethylene-2,4-dihydro-5-methyl-2-phenyl/phenylmethyl-3H-pyrazol- 3-ones
(1991) D. Singh
[No abstract available]
Amperometric ascorbimetric determination of cerium(IV) and Iron(III) with two polarized electrodes
(Springer-Verlag, 1961) D. Singh; Asha Varma; V.S. Agarwala
Amperometric ascorbimetric determinations of cerium(IV) and ferric iron have been carried out at 50°C with two polarized electrodes at 200 and 100 mV respectively. The results obtained are fairly accurate and precise within ±1.0 per cent. A simple method for successive determination of cerium and iron has been developed; and conditions for such estimations have been established. At an acidity of 2.5 M with respect to sulphuric acid, it is possible to ward off the reduction of ferric iron and thereby cerium(IV) is successfully titrated with ascorbic acid in this medium. After completion of the reaction and then lowering the acid concentration to pH 1.5 with aid of ammonium hydroxide, FeIII is titrated with standard ascorbic acid yielding good results. © 1961 Springer-Verlag.
Amperometric Determination of Cerium and Vanadium, and Cerium and Molybdenum in Their Binary Mixtures Using Two Indicator Electrodes
(1967) D. Singh; Uma Bhatnagar
In recent studies in this laboratory, the amperometric method has been applied for the successive determination of cerium and iron [1] and a number of other elements in their binary mixtures [2–3]. In the present investigation this method has been extended for the estimation of mixtures of cerium and vanadium or cerium and molybdenum, using ascorbic acid as titration reagent. Copyright © 1967 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Amperometric iodimetric determination of nickel(II) at constant voltage with two polarised electrodes
(Springer-Verlag, 1962) D. Singh; Asha Varma
The amperometric iodimetric determination of nickel(II) in presence of excess dimethylglyoxime in ammoniacal medium at ph 6.5, has been carried out at 30 millivolts with two polarised electrodes. The redox reaction is quantitative and the results obtained are accurate and satisfactory. The formation of complexes alters the oxidation potential of Ni2+/Ni4+ to a lower value, so as the former is titrable with iodine. The method is simple, sensitive and convenient; and has the advantage that it permits determination of trace amounts of nickel of the order of 10-4 M with fair degree of accuracy. At higher dilutions, error exceeds 5 percent. © 1962 Springer-Verlag.
Biofertilizers for crop improvement
(Nova Science Publishers, Inc., 2023) G.K. Chouhan; D. Singh; A. Mukherjee; S. Singh; A.P.A. Pereira; J.P. Verma
The increasing world population is one of the significant threats to food security. Currently, the cultivable land for agriculture is gradually decreasing, and the soil is becoming infertile. The vigorous use of chemical fertilizers and pesticides is increasing continuously for higher crop productivity to meet the growing populations global food demand. Nowadays, chemical farming is causing many environmental problems that directly and indirectly affect human health. Therefore, organic agriculture (bio-fertilizer, biopesticide, Integrated Crop Management (ICM), Integrated pest management (IPM), crop rotation, green manuring, Farmyard manure (FYM), mixed cropping sequence, etc.) is the only alternative practice for saving our environment and producing quality food for the human being. This book chapter focuses on biofertilizers and their application for crop improvement. Bio-fertilizer contains microorganism providing adequate nutrients to the host plant for proper growth and development. Living microorganisms have a specific function used to prepare biofertilizers to augment plant growth and reproduction. It has great potential to sustain long-term soil fertility and crop production. Nowadays, the application of liquid biofertilizer shows a very effective response in various crops, which has overcome the previous restrictions of biofertilizer applications. However, we need efficient and indigenous biofertilizers to enhance crop productivity, nutritional quality and soil health. These biofertilizers can replace chemical fertilizers. Biofertilizers are eco-friendly, cost-effective and socially acceptable for sustainable agricultural productivity. © 2023 Nova Science Publishers, Inc. All rights reserved.
Conductance of Tetraethylammonium Bromide in Methanol-Dioxane Mixtures at 25°C
(1971) D. Singh; I.P. Aggakwal
The conductance of tetraethylammonium bromide has been measured in pure methanol and in its mixtures with dioxane, the dielectric constant range being 11.65 ≼ D ≼ 32.66. The pair wise association constants and centre to centre cation-anion distance have been calculated with the aid of the Fuoss-Onsager-Skinner and Fuoss-Kraus equations. The centre to centre distance (ion size parameter) and pair wise association constant increase with the decrease in dielectric constant. The plot of log Ka versus 1/D is not linear here and the ak value calculated from the slope of the line drawn through the curvature is 5.21 Å. © 1971, Walter de Gruyter. All rights reserved.
Conductance studies in amide-water mixtures. II. Sodium salts in N,N-dimethylformamide-water mixtures at 35°C
(Kluwer Academic Publishers-Plenum Publishers, 1977) D. Singh; Lal Bahadur; M.V. Ramanamurti
Conductance data for sodium nitrite, chloride, and acetate in water and N,N-dimethylformamide (DMF)-water mixtures (74.82≥D≥42.48) for the concentration range 0.001-0.04 N, as well as the densities, viscosities, and dielectric constants of the solvent mixtures at 35°C, are reported. The data have been analyzed by the Fuoss (1975) equation. The existence of a maximum in the viscosity at a 1:3 mole ratio of DMF and water is indicated. The Walden products for all the three salts pass through a maximum while the equivalent conductances show a minimum with increasing DMF content. The maxima in the Walden product are attributed to the dehydration of ions by the cosolvent (DMF). © 1977 Plenum Publishing Corporation.
Conductometric estimation of thorium in dilute thorium chloride
(Springer-Verlag, 1960) P.G. Menon; D. Singh
Conductometric titrations of thorium chloride against oxalic acid, ammonium oxalate and silver nitrate have been carried out at high dilutions (0.001, 0.0005 and 0.00033 M) of the chloride. Oxalic acid is found to be a suitable titrant for rapid estimation of thorium, the minimum error being +0.5%. The other titrants do not give good results. The titrations with ammonium oxalate indicate the step-wise ionisation of ThCl4 into ThCl22+, ThCl3+ and Th4+. For mixtures of thorium chloride and cerous chloride, only the equivalence point corresponding to complete precipitation of both thorium and cerium is indicated. © 1960 Springer-Verlag.
Copper and streptomycin resistance in Xanthomonas campestris pv. viticola
(1994) R. Chand; P.N. Singh; D. Singh; R. Singh
[No abstract available]
Deformation dependence of 2p-radioactivity half-lives: probe with a new formula across the mass region with Z < 82
(Institute of Physics, 2023) G. Saxena; Mamta Aggarwal; D. Singh; A. Jain; P.K. Sharma; H.L. Yadav
Effect of deformation on half-life of two-proton (2p) radioactivity is investigated across the periodic chart for nuclei with Z < 82. 2p-decay half-lives are estimated by employing our newly proposed semi-empirical formula wherein the nuclear deformation has been incorporated in a phenomenological way. Robustness of the formula is demonstrated as it estimates the measured values quite accurately and, hence, reliably applied to predict the other possible 2p-emitters. For many proton rich nuclei for which experimental data on the decay energies are not available, we have used the theoretical values obtained from our calculations using the relativistic mean-field approach. The uncertainties in the theoretical decay energy values are minimised by machine learning technique. Correlation of 2p-radioactivity with 2p-halo and deformation is probed. Our calculations show the phenomenon of shape coexistence in several 2p-emitters, wherein the prolate shape is found to be more predominant for the ground state. © 2022 IOP Publishing Ltd.
Development of Operating Pressure Diagram for Free Fall Gas Atomization of Liquid Metals
(Iron and Steel Institute of Japan, 2003) D. Singh; S.C. Koria; R.K. Dube
A suitable criterion for the design of gas atomizers used in the free fall gas atomization was developed. It was developed using the knowledge of the dynamics of gas flow rate and interaction between the atomizing field and the molten stream. Limiting plenum pressure was determined for atomization of different metals by considering the limiting velocity of gas. It was concluded that it is safe to atomize the molten stream without running into the risk of metal build-up on the surface of the atomizer.
Effect of different row ratios on growth, yield and quality of pearlmillet and clusterbean intercropping under agri-horti system of vindyan region
(Journal of Pure and Applied Microbiology, 2016) D. Singh; R.N. Meena; Y.K. Ghilotia; A.K. Gupta; R. Meena; V.K. Verma
An experiment was conducted during kharif season of 2011-12 at Agricultural research farm of RGSC, BHU, Barkachha (Utter Pradesh). The maximum plant height, number of leaves per plant and number of tillers of pearlmillet crop was observed 205.23, 26.64 and 3.37 cm at harvest under Pearlmillet+clusterbean (6:1) intercropping system. The maximum no. of grains ear-1, ear girth (cm), ear length (cm) and weight of ear were observed as 1416.75, 10.55 cm, 23.82 cm and 24.75 g under Pearlmillet+clusterbean (6:1) intercropping. The maximum test weight 9.89 g was observed under Pearlmillet + clusterbean (6:1) in intercropping. The maximum grain yield 1554.53 kg ha-1 recorded under pearlmillet sole was significantly higher over rest of the treatments. The maximum straw yield 5104.11 kg ha-1 recorded under pearlmillet sole was significantly superior over rest of the treatments. The maximum biological yield 6658.64 kg ha-1 recorded under pearlmillet sole was significantly superior over rest of the treatments. The highest value of harvest index was recorded under Pearlmillet+clusterbean (4:1) 23.47 (%) in intercropping.
Effects of crop residue burning on aerosol properties, plume characteristics, and long-range transport over northern India
(Wiley-Blackwell, 2014) D.G. Kaskaoutis; S. Kumar; D. Sharma; R.P. Singh; S.K. Kharol; M. Sharma; A.K. Singh; S. Singh; Atinderpal Singh; D. Singh
Aerosol emissions from biomass burning are of specific interest over the globe due to their strong radiative impacts and climate implications. The present study examines the impact of paddy crop residue burning over northern India during the postmonsoon (October-November) season of 2012 on modification of aerosol properties, as well as the long-range transport of smoke plumes, altitude characteristics, and affected areas via the synergy of ground-based measurements and satellite observations. During this period, Moderate Resolution Imaging Spectroradiometer (MODIS) images show a thick smoke/hazy aerosol layer below 2-2.5 km in the atmosphere covering nearly the whole Indo-Gangetic Plains (IGP). The air mass trajectories originating from the biomass-burning source region over Punjab at 500m reveal a potential aerosol transport pathway along the Ganges valley from west to east, resulting in a strong aerosol optical depth (AOD) gradient. Sometimes, depending upon the wind direction and meteorological conditions, the plumes also influence central India, the Arabian Sea, and the Bay of Bengal, thus contributing to Asian pollution outflow. The increased number of fire counts (Terra and Aqua MODIS data) is associated with severe aerosol-laden atmospheres (AOD500 nm>1.0) over six IGP locations, high values of Ångström exponent (>1.2), high particulate mass 2.5 (PM2.5) concentrations (>100-150 µgm-3), and enhanced Ozone Monitoring Instrument Aerosol Index gradient (~2.5) and NO2 concentrations (~6 × 1015mol/cm2), indicating the dominance of smoke aerosols from agricultural crop residue burning. The aerosol size distribution is shifted toward the fine-mode fraction, also exhibiting an increase in the radius of fine aerosols due to coagulation processes in a highly turbid environment. The spectral variation of the single-scattering albedo reveals enhanced dominance of moderately absorbing aerosols, while the aerosol properties, modification, and mixing atmospheric processes differentiate along the IGP sites depending on the distance from the aerosol source, urban influence, and local characteristics. © 2014. American Geophysical Union. All Rights Reserved.
Electrolyte-solvent interactions: Conductance of kcl, rbcl, cscl in methanol-butanol mixtures at 25°c
(1970) D. Singh; L.P. Aggarwal
The conductance data of the chlorides of potassium, rubidium and cesium in methanol-butanol have been made use of in studying ionic association and the effect of solvent composition thereon. The ion size parameter a0 (centre to centre cation-anion distance) and the pair-wise association constant KA at various solvent compositions have been calculated with the aid of the Fuoss-Onsager-Skinner equation. The decrease in dielectric constant results in an increase of ion size parameter a0 and a diminution in the value of ∧0 The sequence of ionic association at a given dielectric constant is : [formula omited]. © 1970, Walter de Gruyter. All rights reserved.
Electrostriction in Mixed Polar Solvents: Viscosity of Silver Nitrate in Methanol-Water Mixtures at 30°C
(1969) D. Singh; y.S. Yadav; B.K. Goel
[No abstract available]
Erratum: Study of neutron magic drip-line nuclei within relativistic mean-field plus bcs approach (International Journal of Modern Physics E (2013) 22: 5 (1350025))
(2013) G. Saxena; D. Singh; M. Kaushik; H.L. Yadav; H. Toki
[No abstract available]
Erratum: Study of two-proton radioactivity within the relativistic mean-field plus bcs approach (International Journal of Modern Physics E (2012) 21: 9 (1250076))
(2013) D. Singh; G. Saxena; M. Kaushik; H.L. Yadav; H. Toki
[No abstract available]
Features of discrete VLF emissions observed at Gulmarg, India during the magnetic storm of 6-7 March, 1986
(2007) R. Singh; Abhay K. Singh; D. Singh; R.P. Singh
During the analysis of archived VLF data from Indian low latitude ground stations, some discrete VLF emissions recorded at the low latitude ground station Gulmarg (geomagnetic latitude 24°26′N; geomagnetic longitude 147°09′E, L = 1.28) during moderate magnetic storm activity (Σ KP- = 32, Kp index varies from 4 to 6 during the observation period) on 6/7 March, 1986 are presented in this paper. The dynamic spectra of these discrete VLF emissions were observed along with tweeks and its harmonics, which is interesting and complex to explain. In most of the events the harmonic frequency of tweeks correlates with the starting frequency of harmonics of discrete emissions. In order to explain the observed features of discrete VLF emissions, we propose cyclotron resonance interaction between whistler mode wave and energetic electrons of inner radiation belt as possible generation mechanism. An attempt is also made to determine parallel energy, anisotropy and wave growth relevant to the generation process of VLF emissions.
Heat radiation reduction in cryostats with multilayer insulation technique
(IOP Publishing Ltd, 2020) D. Singh; A. Pandey; M.K. Singh; L. Singh; V. Singh
Multilayer insulation (MLI) is an important technique for the reduction of radiation heat load in cryostats. The present work is focused on investigation for the selection of suitable reflective layer and spacer material in MLI systems. In our analysis, we have selected perforated double-Aluminized Mylar (DAM) with Dacron, unperforated DAM with Silk-net and perforated DAM with Glass-tissue for their evaluation as the reflective layer as well as spacer materials in MLI technique. Current work would discuss the calculation of the effect of layer density and the number of layers on the heat load. Knowing the key parameters of MLI, we have compared the heat load generation in spherical as well as cylindrical cryostats and the different effect of shielding the cryostat inner or the outer surface on the heat load. © 2020 IOP Publishing Ltd and Sissa Medialab.
Identification of some unknown transcripts from SSH cDNA library of buffalo follicular oocytes
(2013) S.K. Rajput; P. Kumar; B. Roy; A. Verma; H.P. Pandey; D. Singh; S. De; T.K. Datta
A buffalo oocyte-specific subtracted cDNA library was constructed to identify exclusively or preferentially oocyte-expressed genes. The library represented an enriched population of transcripts obtained from oocytes of diverse ovarian follicular origin and at different stages of in vitro maturation. A total of 1173 high-quality sequences of oocyte-specific genes were clustered into 645 unique sequences, out of which 65.76% were represented as singlets and 34.26% as contig expressed sequence tags (ESTs; clusters). Analysis of sequences revealed that 498 of these sequences were identified as a known sequence in mammalian species including buffalo, 103 as uncharacterized ESTs and 44 unknown sequences including 1 novel EST, so far not reported in any species. Gene ontology annotation classified these sequences into functional categories of cellular events and biological processes associated with oocyte competence. Expression status of the isolated unknown ESTs confirmed that many of these are expressed in oocytes exclusively and in others preferentially, some in excess of 80-fold greater in comparison with a variety of somatic tissues. The isolated novel EST was detected to be expressed exclusively in oocytes and testicular cells only. To our knowledge, this is the first report giving a detailed transcriptome account of oocyte-expressed genes in buffalo. This study will provide important information on the physiological control of oocyte development, as well as many questions yet to be addressed on the reproductive process of buffalo. © 2012 The Animal Consortium.