Small-scale phase organization through large-scale inputs in a turbulent boundary layer

A synthetic large-scale motion is excited in a flat plate turbulent boundary layer experiment and its influence on small-scale turbulence is studied. The synthetic scale is seen to alter the average natural phase relationships in a quasi-deterministic manner, and exhibit a phase-organizing influence on the directly coupled small-scales. The results and analysis presented here are of interest from a scientific perspective, and also suggest the possibility of engineering schemes for favorable manipulation of energetic small-scale turbulence through practical large-scale inputs

Equality between Functionals in the Presence of Coproducts

AbstractWe consider the lambda calculus obtained from the simply typed calculus by adding products, coproducts, and a terminal type. We prove the following theorem: The equations provable in this calculus are precisely those true in any set-theoretic model with an infinite base type

Nature & Role of Metal-Oxygen Bond in the Activity of a Zn-Cr-Fe Oxide Catalyst

589-59

Behaviour of Oxide Catalysts During the Catalysed Reactions of Propan-2-ol

586-58

Esterification of methacrylic acid with ethylene glycol over heteropolyacid supported on ZSM-5

Esterification of methacrylic acid with ethylene glycol was carried out over Heteropolyacids [HPA: H4SiW12O40 (STA) and H3PW12O40 (PTA)] supported on ZSM-5. For comparison, the same reaction was carried out over unsupported HPA, H 2SO4, BF3 and PTSA. Among the catalysts studied, HPA showed better activity compared to H2SO4, BF3 and PTSA. Catalytic activity was compared with HPA supported ZSM-5 catalysts. Typical results indicated that 30 wt% PTA supported on ZSM-5 showed nearly the same activity as that of bulk PTA. It was found that the reaction follows first order kinetics with respect to methacrylic acid. The reaction products were identified by 1H-NMR and FT-IR

Kinetics of hydrogen sulfide decomposition in a DBD plasma reactor operated at high temperature

The present study investigates the kinetics of hydrogen sulfide (H 2 S) decomposition into hydrogen and sulfur carried out in a nonthermal plasma dielectric barrier discharge (NTP-DBD) reactor operated at ∼ 430 K for in situ removal of sulfur condensed inside the reactor walls. The dissociation of H 2 S was primarily initiated by the excitation of carrier gas (Ar) through electron collisions which appeared to be the rate determining step. The experiments were carried out with initial concentration of H 2 S varied between 5 and 25 vol% at 150 mL/min (at standard temperature and pressure) flow rate in the input power range of 0.5 to 2 W. The reaction rate model based on continuous stirred tank reactor (CSTR) model failed to explain the global kinetics of H 2 S decomposition, probably due to the multiple complex reactions involved in H 2 S decomposition, whereas Michaelis-Menten model was satisfactory. Typical results indicated that the reaction order approached zero with increasing inlet concentration

Quenching of fluorescence of aromatic molecules by graphene due to electron transfer

Investigations on the fluorescence quenching of graphene have been carried out with two organic donor molecules, pyrene butanaoic acid succinimidyl ester (PyBS, I) and oligo(p-phenylenevinylene) methyl ester (OPV-ester, II). Absorption and photoluminescence spectra of I and II recorded in mixture with increasing the concentrations of graphene showed no change in the former, but remarkable quenching of fluorescence. The property of graphene to quench fluorescence of these aromatic molecules is shown to be associated with photo-induced electron transfer, on the basis of fluorescence decay and time-resolved transient absorption spectroscopic measurements.Comment: 18 pages, 6 figure

Dynamics of Metallic Particle Contamination in Gas Insulated Substation (GIS)

This paper analyses the movement of free conducting particles inside a single phase Gas Insulated Bus duct(GIB).A two dimensional mathematical model was proposed for determining the movement pattern of metallic particle in GIB by considering all the forces acting on the particle like gravitational, drag and the electric field forces. These particles may be free to move in the electric field or may be fixed on the conductors, thus enhancing local surface fields. Electric fields at the instantaneous contaminated particle locations were computed using Charge Simulation Method (CSM).To determine the particle trajectory in a single phase Gas Insulated Bus duct (GIB), an enclosure diameter 152 mm and conductor diameter 55 mm is considered. The simulation of the particle movement was carried under different AC voltage levels like 100KV, 132KV, 145KV and 175KV class enclosure of GIB for aluminum, copper and silver particles. The results of the simulation have been presented and analyzed in this paper

Common Liquidity Shocks and Market Collapse: Lessons From the Market for Perps

We show how a high degree of commonality in investor liquidity shocks can diminish incentives for intermediaries to keep markets open and lead to market collapse, even without information asymmetry or news affecting fundamentals. We motivate our model using the perpetual floating-rate note market where two years of explosive growth – in which issues by high quality borrowers were placed with institutional investors and traded in a liquid secondary market – were followed by a precipitous collapse when market intermediaries withdrew due to large order imbalances. We shed new light on the trade-off between ownership concentration and market liquidity

Studies on the Geology and Beneficiation of Chandak Magne-site Deposit from Pithoragarh District, Uttar Pradesh

Stringent operating conditions in modern steel making furnaces demand high quality basic refractories based on magnesia. Source of good quality natural magnesite cont-ains considerable amounts of SiO2 and fluxing agents. Therefore, appropriate measures are to be taken to ensure the availablity of good quality magnesite. Measures for meeting the demand of quality magnesite are follows:- i) Upgrading of the presently available natural magnesite by various beneficiation techniques ; ii) Production of high quality magnesia from sea water