Numerical Simulation of MIG for 42 GHz, 200 kW Gyrotron

A triode type magnetron injection gun (MIG) of a 42 GHz, 200 kW gyrotron for an Indian TOKAMAK system is designed by using the commercially available code EGUN. The operating voltages of the modulating anode and the accelerating anode are 29 kV and 65 kV respectively. The operating mode of the gyrotron is TE₀₃ and it is operated in fundamental harmonic. The simulated results of MIG obtained with the EGUN code are validated with another trajectory code TRAK.     

Operads and knot spaces

We model the homotopy fiber of the inclusion of the space of long knots in dimension into the corresponding space of immersions, through an operad structure on compactifications of configuration spaces. Development of this operad structure involves defining an operad structure on the simplicial model for the two-sphere. We apply results of McClure and Smith to deduce the existence of a two-cubes action on .

     

Has new physics already been seen in B(d) meson decays?

We show in a model independent way that, within the standard model, the deviation in the measured B(d){0}-B[over](d){0} mixing phase caused by pollution from another amplitude is always less in magnitude, and has the same sign as, the weak phase of the polluting amplitude. The exception is to have large destructive interference between the two amplitudes: any deviation larger than a few degrees is only possible if the observed decay rate results from fine-tuned cancellations between significantly larger amplitudes. This is unlikely given our understanding of B decays. Even if the deviation reduces to a few degrees in the future, new physics would still likely be implied.     

Isothermal nanocrystallization kinetics during polymorphic transformation

The experimental value of Avrami exponent during polymorphic nanocrystallization deviates from the theoretical prediction of the Kolmogorov-Johnson-Mehl-Avrami (KJMA) isothermal kinetics. The assumption of negligible nuclei volume, implicit in KJMA, is violated for all such transformations involving nano-sized grains. A discrete adaptation of the KJMA model is used to study the effect of the non-zero nuclei volume on nanocrystallization kinetics. Transformations initiated by homogeneous and heterogeneous nucleation are analyzed under constant nucleation and growth rate conditions. For homogeneous nucleation, a universal scaling relation with respect to finite nuclei size is found. In contrast to this, for the heterogeneous case a series of linear scaling relations are observed with respect to the nucleation conditions.     

Pricing surplus server capacity for mean waiting time sensitive customers

We consider a queueing model wherein the resource is shared by two different classes of customers, primary (existing) and secondary (new), under a service level based pricing contract. This contract between secondary class customers and resource manager specifies unit admission price and quality of service (QoS) offered. We assume that the secondary customers’ Poisson arrival rate depends linearly on unit price and service level offered while the server uses a delay dependent priority queue management scheme. We analyze the joint problem of optimal pricing and operation of the resource with the inclusion of secondary class customers, while continuing to offer a pre-specified QoS to primary class customers. Our analysis leads to an algorithm that finds, in closed form expressions, the optimal points of the resulting non-convex constrained optimization problem. We also study in detail the structure and the non-linear nature of these optimal pricing and operating decisions.     

Electrophoresis of hydrophilic/hydrophobic rigid colloid with effects of relaxation and ion size

This article deals with a semi‐analytical study on the electrophoresis of charged spherical rigid colloid by considering the effects of relaxation and ion size. The particle surface is taken to be either hydrophilic or hydrophobic in nature. In order to consider the ion size effect we have invoked the Carnahan and Starling model (J. Chem. Phys. 1969, 51, 635‐636). The mathematical model is based on Stokes equation for fluid flow, modified Boltzmann equation for spatial distribution of ionic species and Poisson equation for electric potential. We adopt a linear perturbation technique under a weak electric field assumption. An iterative numerical technique in employed to solve the coupled set of perturbed equations. We have validated the numerically obtained electrophoretic mobility with the corresponding analytical solution derived under low potential limit. Going beyond the widely employed Debye‐Hückel linearization, we have presented the results for a wide range of surface charge density, electrolyte concentration, and slip length to Debye length ratio. We have also identified several interesting features including occurrence of local maxima and minima in the mobility for critical choice of pertinent parameters.     

Study on groundwater quality in parts of Rajasthan with special reference to uranium contamination

Journal of Radioanalytical and Nuclear Chemistry - Herein, a practical and simple reduction method was used to prepared the nanoscale composites of hydroxyapatite (HAP) coated with zero valent iron...     

Isolation and Characterization of Cross-Neutralizing Human Anti-V3 Single-Chain Variable Fragments (scFvs) Against HIV-1 from an Antigen Preselected Phage Library

Applied Biochemistry and Biotechnology - Recently conducted human phase- I trials showed protective effect of anti-HIV-1 broadly neutralizing antibodies (bnAbs). The V3 region of the HIV-1 envelope...