The BHIL Culture in Central India

There is a vast diversity of cultures in Asia. This diversity is under threat by the pressures of nationalism and of globalization. This essay discusses the Bihil culture of central India as a microcosm of some of these issues facing cultural diversity

Three-Phase Isolated Boost DC-DC Converter for High Voltage Applications

The voltage fed DC-DC converter has been suffering from problems associated with large transformer leakage inductance due to high transformer turn ratio when it is applied to low-voltage, high-current step-up application such as fuel cells. This paper proposes a new three-phase voltage fed DC-DC converter, which is suitable for high-voltage, high-current applications. The transformer turn ratio is reduced to half owing to ?-Y connection. The zero-voltage and zero-current switches (ZVZCS) for all switches are achieved over wide load range without affecting effective duty cycle. A clamp circuit not only clamps the surge voltage but also reduces the circulation current flowing in the high-current side, resulting in significantly reduced conduction losses. The duty cycle loss can also be compensated by operation of the clamp switch.The detailed design and operating principles are described and simulated using Pspice. The proposed converter is very attractive for electrolyser application.Keywords: High power DC–DC converter, three-phase DC-DC converter, active clamp circuit, Isolation transformer

Production of Cold-Active Bacterial Lipases through Semisolid State Fermentation Using Oil Cakes

Production of cold active lipase by semisolid state fermentation involves the use of agroindustrial residues. In the present study, semisolid state fermentation was carried out for the production of cold active lipase using Micrococcus roseus, isolated from soil samples of Gangotri glaciers, Western Himalayas. Among various substrate tested, groundnut oil cake (GOC) favored maximal yield of lipases at 15 ± 1°C within 48 h. Supplementation of glucose 1% (w/v) as additional carbon source and ammonium nitrate 2% (w/v) as additional nitrogen source enhanced production of lipase. Addition of triglycerides 0.5% (v/v) tends to repress the lipase production. Further mixed preparation of groundnut oil cake (GOC) along with mustard oil cake (MOC) in the ratio of 1 : 1, and its optimization resulted in improved production of cold active lipase. The enzyme exhibited maximum activity at 10–15°C and was stable at temperatures lower than 30°C. The lipase exhibited optimum activity at pH 8 and showed more than 60% stability at pH 9. Semisolid state fermentation process by utilizing agroindustrial wastes will direct to large-scale commercialization of lipase catalyzed process in cost-effective systems