Banaras Hindu University

About: Banaras Hindu University is a education organization based out in Varanasi, Uttar Pradesh, India. It is known for research contribution in the topics: Population & Catalysis. The organization has 11858 authors who have published 23917 publications receiving 464677 citations. The organization is also known as: Kashi Hindu Vishvavidyalay & Benares Hindu University.

Antioxidant and antibacterial potential of pomegranate peel extracts

Abstract: Pomegranate peels of Ganesh variety were subjected to extraction using different solvents viz. water, methanol and ethanol either alone or in combination with water. The extraction yield, antioxidant activity (DPPH and ABTS inhibition) and total phenolic contents were evaluated. Highest yield was obtained from 50 % ethanol: 50 % water (16.3 ± 1.99 %). The DPPH and ABTS inhibition activity was found to be the highest for methanol and 70 % ethanol: 30 % water extract (79.5 ± 6.5; 94.6 ± 6.10), respectively. The phenolic content was the highest in the aqueous extract (438.3 ± 14.15). The antibacterial activity of peel extracts was tested against four bacterial strains, Staphylococcus aureus, Enterobacter aerogenes, Salmonella typhi and Klebsiella pneumoniae and the extracts demonstrated remarkable antibacterial activities against all the tested bacterial strains. The 70 % ethanol: 30 % water and 100 % water extract had a higher antioxidant activity and phenolic content and has the potential for nutraceutical application.

Evolution of aluminide coating microstructure on nickel-base cast superalloy CM-247 in a single-step high-activity aluminizing process

Abstract: This study deals with the aluminizing of a directionally cast Ni-base superalloy, namely CM-247, by a single-step process using a high-activity pack. It is observed that significant incorporation of Al into the substrate surface during aluminizing continues over a period of about 1 hour and is not restricted merely to the first few minutes, as reported in the literature. Based on the microstructural details of the coatings formed at various stages of aluminizing, it is concluded that the coating growth in the above process takes place primarily by inward Al diffusion initially, followed by an intermediate stage when the growth involves both inward Al and outward Ni diffusion. In the final stages, the outward diffusion of Ni dominates the coating formation process. The above mechanism of coating formation is different from the one that prevails in the conventional two-step high-activity coating process in that the reaction front for the formation of NiAl remains spatially stationary despite the outward diffusion of nickel during the intermediate stage. It is also shown in the present study that the content of the Al source in the pack affects the coating structure significantly. It is further demonstrated that the microstructure of the aluminide coatings depends not only on the amount of Al incorporated in the sample during aluminizing but also on the time over which the uptake of this Al takes place.

The Contribution of Three-Body Overlap Forces to the Dynamical Matrix of Alkali Halides

Abstract: The so-called S2-approximation in the Heitler-London theory of ionic crystals as developed by Lowdin gives rise to a three-body contribution in the cohesive energy. The present paper describes a method of deriving the coupling coefficients for the three-body potential from expressions given by Lundqvist. These coupling coefficients involve certain lattice sums which can be evaluated in terms of incomplete gamma functions by a method due to Born and Bradburn. A new lattice dynamical model of ionic solids has been suggested which is obtained by injecting the three-body coupling coefficients into the shell model of Woods et al. in a way that preserves symmetry in the wave vector space. Preliminary calculations show that this model can prove superior to other current models. Die sogenannte S2-Naherung in der Theorie von Heitler-London der Ionenkristalle, wie sie von Lowdin entwickelt wurde, gibt Anlas zu einem Dreikorperbeitrag in der Anziehungsenergie. Die vorliegende Arbeit beschreibt eine Methode zur Ableitung der Kopplungskoeffizienten fur das Dreikorperpotential aus den Ausdrucken, die von Lundqvist gegeben wurden. Diese Kopplungskoeffizienten schliesen gewisse Gittersummen ein, die mit unvollstandigen Γ-Funktionen nach der Methode von Born und Bradburn berechnet werden konnen. Eine neues gitterdynamisches Modell der Ionenfestkorper wird vorgeschlagen, das durch das Einbeziehen der Dreikorperkopplungskoeffizienten in das Schalenmodell von Woods et al. in einer Weise erhalten wird, die die Symmetrie im Raum der Wellenvektoren erhalt. Vorlaufige Berechnungen zeigen, das dieses Modell sich anderen gelaufigen Modellen als uberlegen erweisen kann.

Single identified hadron spectra from √SNN=130 GeV Au+Au collisions

Abstract: Transverse momentum spectra and yields of hadrons are measured by the PHENIX collaboration in Au+Au collisions at √s NN =130 GeV at the Relativistic Heavy Ion Collider. The time-of-flight resolution allows identification of pions to transverse momenta of 2 GeV/c and protons and antiprotons to 4 GeV/c. The yield of pions rises approximately linearly with the number of nucleons participating in the collision, while the number of kaons, protons, and antiprotons increases more rapidly. The shape of the momentum distribution changes between peripheral and central collisions. Simultaneous analysis of all the p T spectra indicates radial collective expansion, consistent with predictions of hydrodynamic models. Hydrodynamic analysis of the spectra shows that the expansion velocity increases with collision centrality and collision energy. This expansion boosts the particle momenta, causing the yield from soft processes to exceed that for hard to large transverse momentum, perhaps as large as 3 GeV/c.