Browsing by Author "Arvind Singh"

Now showing 1 - 17 of 17

A Theoretical and Computational Study of Structure-Property Relationship in Five Binary Liquid Alloys
(John Wiley and Sons Inc, 2024) Arvind Singh; Raj Kumar Patel; Raj Kumar Mishra; R. Lalneihpuii
A theoretical model is proposed in this work for the evaluation of composition-dependent thermophysical properties such as the isothermal compressibility, velocity of sound and Debye temperature of liquid binary alloys. Using a square-well (SW) model potential function under mean spherical model approximation, the composition-dependent atomic-level structural functions of Al1-xCux, Ag1-xCux, Au1-xCux, Ag1-xAlx, and Au1-xAgx alloys have been determined and compared with available experimental data. An extensive computation was done to calculate the composition-dependent isothermal compressibility through the structure factor in the long wavelength limit (k→0), and then we employed this data to investigate the velocity of sound in the considered melts. This yields the fundamental maximum frequency with which the constituent particles are vibrating in the melts and is used to determine the composition-dependent Debye temperature, ΘD. The computed Debye temperature of considered melts using the Square-well potential function is found to be in satisfactory agreement with the available DFT and MD simulation results. © 2024 Wiley-VCH GmbH.
Amino acids assisted growth of methylammonium lead iodide cuboidal crystals for solar cell applications
(Elsevier B.V., 2023) Saurav K. Ojha; Divya Singh; Aditya Kumar; Arvind Singh; Ranjan K Singh; Animesh K. Ojha
The cuboidal crystals of methylammonium lead iodide (MAPbI3) with controlled shapes and sizes are successfully synthesized by monitoring their growth in the precursor solution using different α-amino acids. The directional growth of MAPbI3 crystals is carried out by promoting crystallization at molecular level in the presence of an optimum concentration of α-amino acids. Alanine (ALA), having relatively larger value of dipole moment, induces directional growth to the MAPbI3 crystals at low concentration. The optical and electrical properties of the thin films formed by the grown MAPbI3 crystals are also enhanced. The dipole moment of the amino acids plays an important role in directional growth of MAPbI3 crystals. The least area of I-V hysteresis curve in the thin film prepared with 1.5 wt% of isoleucine (ISO) indicates minimum loss of energy which makes it suitable for application in perovskite solar cells (PSCs). © 2023 Elsevier B.V.
Boerhaavia diffusa: An over-exploited plant of medicinal importance in eastern Uttar Pradesh [8]
(2007) Arvind Singh
[No abstract available]
Comparative growth behaviour and leaf nutrient status of native trees planted on mine spoil with and without nutrient amendment
(Academic Press, 2001) Arvind Singh; J.S. Singh
The effect of nutrient amendment on growth of nine indigenous tree species planted on coal mine spoil was studied. Greater growth in fertilized plots was accompanied by greater foliar N and P concentrations in all species. The response to fertilization varied among Species and was greater in non-leguminous than in leguminous species. Furthermore, leguminous species exhibited higher growth rates compared to non-leguminous species. The log-transformed height-diameter relationships were significant for all tree species and treatments. Acacia catechu, Dalbergia sissoo, Gmelina arborea and Azadirachta indica fitted the elastic similarity model of tree growth; whereas Pongamia pinnata and Phyllanthus emblica followed the constant stress model. Tectona grandis was the only species which fitted the geometric similarity model. In Albizia lebbeck and Terminalia bellirica, the b-values (the gradients of the log-transformed height to diameter relationships) were considerably lower (<0.5), and these two species did not fit any model of tree growth. In several cases, the b-values were considerably influenced by nutrient amendment. The log-transformed crown mass and trunk mass relationships were Significant for all treatments and species. The slope of the crown mass:trunk mass relationship was near unity in A. indica, D. sissoo, G. arborea, P. emblica, P. pinnata, T. grandis, and T. bellirica. However, in A. catechu and A. lebbeck, this slope was well below unity suggesting a greater allocation to non-photosynthetic tissue. Fertilizer amendment resulted in a heavier crown relative to trunk in A. indica, T. grandis and T. bellirica. © 2001 Annals of Botany Company.
Effect of fertilization on N and P resorption efficiency of selected leguminous and nonleguminous tropical trees planted on coal mine spoil
(2004) Arvind Singh
Influence of NPK fertilization on N and P resorption efficiency was studied in nine native tropical tree species planted on coal mine spoil. Of these, Acacia catechu, Albizia lebbeck, Dalbergia sissoo and Pongamia pinnata were legumes, while Azadirachta indica, Gmelina arborea, Phyllanthus emblica, Tectona grandis and Terminalia bellirica were nonlegumes. The N and P resorption efficiencies dropped in fertilized plots in all the species. Nonleguminous tree species had exhibited greater efficiency for N resorption than leguminous species. However, no such trend emerged for P resorption between both the groups, as the two nonlegumes A. indica and G. arborea had resorbed P in the range of leguminous tree species. The study indicates that nutrient enrichment reduces internal cycling of nutrients thus facilitating greater amount of nutrient return to soil which in turn would enhance the reclamation process by allowing the colonization of more_species due to increased habitat fertility. © Indian Institute of Science.
Effect of nutrient enrichment on native tropical trees planted on Singrauli Coalfields, India
(2000) Arvind Singh; A.K. Jha; J.S. Singh
Growth performance of nine native tropical tree species planted on mine spoil under two levels of NPK treatment was studied by measuring height and diameter. Of the nine species, four were leguminous. All the tree species responded positively to NPK fertilization; however, the impact on leguminous species was little compared to non-leguminous species. In general, the height/diameter ratio decreased from control to full-dose NPK treatment, suggesting that nutrient enrichment influenced the resource allocation pattern such that the diameter growth was favored. The log-transformed height-diameter relationships were significant for the three treatments in all the tree species. The slopes (β) obtained were compared with three different models of tree growth (i.e., elastic similarity, geometric similarity, and constant stress). Acacia catechu, Dalbergia sissoo, Gmelina arborea, and Azadirachta indica fitted the elastic similarity model, whereas Pongamia pinnata and Phyllanthus emblica followed the constant stress model. Tectona grandis was the only species that followed the geometric similarity model. In Albizia lebbeck and Terminalia bellirica, the β values were considerably lower (i.e., below 0.5) and these two species did not fit any of the three models of tree growth. In several cases the β values were considerably influenced by nutrient enrichment.
Evaluation of direct seeding of tree species as a means of revegetation of coal mine spoils
(2000) A.K. Jha; Arvind Singh; A.N. Singh; J.S. Singh
[No abstract available]
Growth and leaf nutrient status of companion species as influenced by neighbouring species in mixed plantations raised on mine spoil
(2006) Arvind Singh
Effect of neighbouring species on growth and foliar nutrient status of companion species was studied in mixed plantation raised on coal mine spoil. The three combinations used were legume:legume,legume:non-legume and non-legume:non-legume. The neighbouring species had influenced the growth and foliar N and P status of companion species in mixed plantations. Acacia catechu had shown greater growth and foliar N and P status when grown with neighbouring legume Pongamia pinnata than when grown with another neighbouring legume Albizia lebbeck. The growth and foliar N and P status of non-legumes Gmelina arborea and Terminalia bellerica were greater when these species were grown with the legume Pongamia pinnata than when grown with non-legume. The legume Pongamia pinnata had exhibited better growth and increased N and P concentration when grown with non-legumes Gmelina arborea and Terminalia bellerica than when grown with legume Acacia catechu. Tectona grandis, on other hand side, had shown reduced growth and foliar N and P concentration, when grown with neighbouring legumes Dalbergia sissoo and Leucaena leucocephala than when grown with neighbouring non-legume Dendrocalamus strictus. The growth rates (height, diameter and volume increments) were positively related to foliar N and P concentration. © International Society for Tropical Ecology.
Herbaceous biomass yield on an age series of naturally revegetated mine spoils in a dry tropical environment
(2004) Arvind Singh
The influence of mine spoils age on herbaceous biomass yield was studied in a dry tropical environment. Naturally revegetated mine spoils selected were 1-, 5-, 10-, 15- and 20-year-old. The biomass yield increased with increasing age of the spoils. The root, shoot and total biomass were significantly greater on 5-, 10-, 15- and 20-year-old spoils compared to 1-year-old young spoil. A stabilizing trend in biomass yield started after 10 years, reaching almost a stage of saturation on 20-year-old spoil. Spoil age had affected root/shoot ratio also. However, the root/shoot ratio exhibited a decreasing trend with advance in the age of the spoil.
Herbaceous species composition of an age series of naturally revegetated coal mine spoils on Singrauli Coalfields, India
(2006) Arvind Singh
The herbaceous species composition of 2-, 5- and 10-year-old age series of coal mine spoils was studied at Singrauli coalfields, India. The number of species increased with increasing age of the spoil. Two- and five-year old spoils were dominated by species belonging to the families Poaceae and Fabaceae, while the 10-year-old spoil was dominated by species belonging to the families Poaceae and Asteraceae. © Indian Institute of Science.
Influence of a developing tree canopy on the yield of Pennisetum pedicellatum sown on a mine spoil
(Wiley-Blackwell, 1997) Arvind Singh; A.K. Jha; J.S. Singh
Shoot and root biomass yield of a sown grass, Pennisetum pedicellatum, were measured at below-canopy, canopy edge and open locations in young monoculture stands of eight tree species planted on a coalmine spoil. Incident light as percentage of full sunlight decreased from open to canopy edge to below-canopy locations. The shoot and root weights of Pennisetum in different tree stands for each of the three locations were significantly different and were significantly related to each other, and to percentage sunlight across all tree species plots and locations. The gradient of incident light was the principal factor governing the gradient of grass biomass under developing canopies of tree plantations on the mine spoil.
Influence of mulching on plant growth performance in young plantation plots on coal mine spoil
(2001) A.K. Jha; Arvind Singh; A.N. Singh; J.S. Singh
Plantation of Dendrocalamus strictus was raised on coal mine spoil at Jayant project, NCL, Singrauli in June 1993. Half and full dose of NPK fertilizer was applied. Full dose of NPK fertilizer was nitrogen as urea (60 kg ha-1), phosphorus as single superphosphate (30 kg ha-1) and potash as muriate of potash (40 kg ha-1). Half dose of NPK treatment increased the height growth more whereas full dose of NPK treatment enhanced markedly the number of culms/ clump and diameter growth of D. strictus.
Management algorithms for acute ST elevation myocardial infarction in less industrialized world
(Elsevier B.V., 2017) Sundeep Mishra; S. Ramakrishnan; Abraham S. Babu; Ambuj Roy; Vinay K. Bahl; Kanha V. Singru; Sanjay Chugh; Shantanu Sengupta; Upendra Kaul; S. Nagendra Boopathy; Yajnik Nirmit; Uday M. Jadhav; John Jose; Vitull Gupta; Hriday K. Chopra; Arvind Singh; B.K.S. Sastry; Subramanian Thiyagarajan
[No abstract available]
Menace of Japanese encephalitis in rural areas of eastern Uttar Pradesh [4]
(2007) Arvind Singh
[No abstract available]
Revegetation of coal-mine spoils using Prosopis juliflora in Singrauli coalfield is a harmful practice from an ecological viewpoint [10]
(2007) Arvind Singh
[No abstract available]
Temperature induced modifications in shapes and crystal phases of MoO3 for enhanced photocatalytic degradation of dye waste water pollutants under UV irradiation
(Elsevier Ltd, 2019) Arvind Singh; Sumeet Kumar; Bilal Ahmed; Ranjan K. Singh; Animesh K. Ojha
Rod shaped structures of molybdenum trioxide (MoO3) were synthesized at low temperature using simple and low cost method. The synthesized materials were characterized by different characterization techniques. The effect of annealing temperature on crystal structure and optical properties of MoO3 was investigated. The hexagonal phase (h-MoO3) was observed up to 300 °C and beyond this temperature, the phase of the MoO3 is changed to orthorhombic (α-MoO3). The transition of crystal phase (h-MoO3 to α-MoO3) was investigated by analyzing the X-ray diffraction (XRD), Raman and DSC measurements. The shift in the wavenumber position of 971 cm−1 (Mo–O stretching) peak with temperature also substantiates the phase transition in MoO3 structure. The shape of nanostructured MoO3 was modified with annealing temperature. The change in crystal phases and shapes with temperature may result defects in the structure, which essentially modify the structural and optical properties of the material. The photocatalytic properties of the synthesized materials were studied on methylene blue (MB) dye under UV-irradiation. The sample annealed at 400 °C (M4) show excellent photodegradation compared to other samples. It could be due to the combined effects of shape (helical) and defects (oxygen vacancies) present in M4, as supported by the electron paramagnetic resonance (EPR) measurements. Among the various radicals, OH[rad] plays an important role in photodegardation of the MB dye. © 2019 Elsevier B.V.
Tree canopy development in young plantations raised on coalmine spoil affects the growth of herbaceous vegetation
(Indian For, 1999) A.K. Jha; Arvind Singh; A.N. Singh; J.S. Singh
Pennisetum pedicellatum and Heteropogon contortus grasses were seeded in tree plantation plots on coal mine spoils at Jayant Project, NCL, Singrauli. After three year of raising of plantations the tree canopies affected the growth of seeded grasses. The dense canopy of D. strictus, P. pinnata and L. leucocephala completely eliminated the seeded grasses H. contortus and P. pedicellatum. Under the dense canopy for G. arborea only H. contortus grows well whereas P. pedicellatum was eliminated. Thus to increase the herbaceous plant biodiversity and for the establishment of stable plant communities thinning of plantation plots after 3-4 years is essential, and H. contortus should be preferred in ground seeding compared to P. pedicellatum.