Steel for a billion people: a brief appraisal of Indian steel research

A compact overview of the iron and steel industry in India is presented along with the current status of research and development activity.     

Activation of rat androgen receptor by androgenic ligands is unaffected by antiandrogens in Saccharomyces cerevisiae

The E. coli lacZ has been utilized as a reporter to evaluate ligand-mediated activation of the rat androgen receptor (AR) in Saccharomyces cerevisiae strain YCR1. beta-galactosidase activity was androgen-specific and was found to be inducible approximately 260-fold by dihydrotestosterone (DHT), testosterone and R1881. None of the antiandrogens tested was able to antagonize the DHT-dependent induction of beta-galactosidase activity. In the gel retardation assay, exposure of the receptor to DHT in vitro led to the formation of a protein-DNA complex that was not detected in yeast extracts unexposed to hormone. However, activation of AR by a steroidal (cyproterone acetate) and a non-steroidal antiandrogen (flutamide) either alone or in combination with DHT also results in a similar migration pattern. Additionally, LEM1, the ABC transporter that selectively modulates the biological potency of steroids in yeast, although operative in YCR1, was not responsible for antiandrogen resistance. These results thus indicate the involvement of other non-receptor factor(s) in mediating the effect of antiandrogens in yeast.     

Tight-binding calculations of Si-H clusters using genetic algorithms and related techniques: Studies using differential evolution

A nonorthogonal tight-binding model has been developed for the system containing Si and H, where the energy functional included the contributions of both electronic and pairwise interaction between the atoms. In order to calculate the ground state structures of various clusters, energy minimization was carried out using Differential Evolution: a very recently developed biologically inspired computing technique, belonging, in general, to the family of Genetic Algorithms (GAs), but having a number of advantages over its conventional forms.     

A finite element modeling analysis of flow and mass transfer through nonspherical bubbles in a copper converter

A mathematical model has been developed for the flow and mass-transfer processes associated with the nonspherical, deformed bubbles in a copper converter. The case of an isolated reacting bubble has been studied numerically by solving the pertinent transport equations with Galerkin finite element modeling (FEM) technique. The continuous change in bubble shape and size has been handled through an adaptive grid generation technique based upon a transfinite inter-polation scheme. Some of the results have shown a significant difference from the earlier analysis of spherical bubbles. The numerical predictions are well in accord with the existing theory and measurements.     

Fungal degradation of 2,4-Dinitrotoluene and nitroglycerin in batch and fixed-film bioreactors

Abstract

Energetic materials, which are the main components of propellants and other explosive mixtures, are characterized as hazardous and must be disposed in an environmentally sound way. Microbially mediated destruction of energetic chemicals shows great promise for converting these substances to innocuous products. A number of fungal species namely Phanerochaete chrysosporium, Penicillium corylophilum, Aspergelus fumigatus, and Geotricum candidum have the ability to attack energetic materials and completely mineralize them into carbon dioxide and water. This paper presents results on the biodegradation of 2,4-Dinitrotoluene and nitroglycerin by P. chrysosporium in completely mixed batch reactors and in continuous flow immobilized bed systems. The fungus was able to degrade both compounds and the observed intermediates in the presence of a co-substrate.     

Image Thinning by Neural Networks

An image thinning technique using a neural network is proposed. Using different activation functions at different layers, the proposed neural network removes the boundary pixels from four directions in such a manner that the general configuration of the input pattern is unaltered and the connectivity is preserved. The resulting object, called a skeleton, provides an abstraction of the global shape of the object. The skeleton is often useful for geometrical and structural analysis of the object. The output skeleton here satisfies the basic properties of a skeleton, namely connectivity and unit thickness. The proposed method is experimentally found to be more efficient in terms of better medial axis representation and robustness to boundary noise over a few existing algorithms. ID="A1" Correspondence and offprint requests to: Dr A. Datta, Indian Statistical Institute, 203 B. T. Road, Calcutta – 700 108, India. Email: amitava@isical.ac.in     

Regulating Crown and Flatness During Hot Rolling: A Multiobjective Optimization Study Using Genetic Algorithms

A genetic algorithms-based multioptimization study has been carried out for the hot rolling practice in an integrated steel plant. The aim is to identify the parameter settings and rolling schedules that would result in the optimum values of crown and flatness--two major parameters related to the geometric tolerances in the rolled sheet. Two objective functions and some appropriate constraints have been formulated for this purpose, and two different evolutionary algorithms are tried out on them. The optimized results are presented in the forms of Pareto fronts and discussed in the context of the actual process.