Cobalt- and Nickel-containing enzyme constructs from the sequences of methanogens

Aim. The conserved domain of sequences revealed in methanogens is considered for designing enzymes among which the attention has been focused on the metalloenzymes showing evolutionary significances. Methods. Molecular evolution, molecular modelling and molecular docking methods. Results. Molecular evolutionary hypothesis has been applied for designing cobalt-containing sirohydrocholine cobalt chelatase and nickel-containing coenzyme F420 non-reducing hydrogenase from conserved domains encompassing metaland substrate-binding sites. It was hypothesized that if any enzyme has similar or identical conserved domain in its catalytic region, the construct can bring similar catalytic activity. Using this approach, the region which covers such functional module has to be modeled for yielding enzyme constructs. The present approach has provided a high likelihood to design stable metalloenzyme constructs from the sequences of methanogens due to their low functional divergence. The resulted enzyme constructs have shown diverse reaction specificity and binding affinity with respective substrates. Conclusions. It seems to provide a new knowledge on understanding the catalytic competence as well as substrate-specificity of enzyme constructs. The resulted enzyme constructs could be experimentally reliable as the sequences originally driven from methanogenic archaea

Development of an In house Computer Code for the Simulation of Detonation Shock Dynamics in Underwater Explosion Scenario

Detonation Shock Dynamics (DSD), involved in an underwater explosion scenario is numerically simulated by an in-house computer code, ‘DSSDYN’. The simulation is based on Chapman-Jouguet (CJ) theory, formulated in Arbitrary Lagrangian Eulerian frame work. Specifically, the propagation of detonation front is simulated with‘Burn Fraction Model’. The classical burn fraction model is improved for achieving better computational efficiency. The simulation capability of DSS-DYN is demonstrated through a case study on explosion of PETN charge under the deep-water medium.Through this study, the salient features of DSD with better insight have been brought out. Besides, the physical parameters, such as work potential of PETN, are predicted efficiently.The apportionment of energy distributions indicates that about 70 % of chemical energy of explosive is transmitted to the surrounding water that is the major contribution of damage potential of the explosive. The predictions of peak velocity and peak pressure values by DSS-DYN and LS-DYNA show satisfactory comparison.DSS-DYN consumes lesser computational time (~1h), compared to LS-DYNA (~3h)

Production and Preliminary Characterization of Alkaline Protease from Aspergillus flavus

Proteases are being an industrial candidate, which are widely used in food, bakery, and beverage and detergent industry. In leather industry, alkaline proteases are exhibiting a prominent role in unhairing and bating processes. An extensive use of filamentous fungi, especially Aspergillus species has been studied elaborately. Although, the significant application of alkaline protease produced from these strains in leather industry is being limited. Aspergillus flavus and Aspergillus terreus found as the potential strains for production of tannery protease in submerged fermentation. To improve the productivity of this enzyme in liquid broth, various media ingredients have been optimized. The crude and partially purified proteases preliminarily characterized and used for unhairing processes at lab scale in tannery. The protease obtained from these strains showed the good activity in wide alkaline condition at 50 °C suggesting the possibility of using in leather and detergent industry

Measurement of the Residual Stresses and Investigation of Their Effects on a Hardfaced Grid Plate due to Thermal Cycling in a Pool Type Sodium-Cooled Fast Reactor

In sodium-cooled fast reactors (SFR), grid plate is a critical component which is made of 316 L(N) SS. It is supported on core support structure. The grid plate supports the core subassemblies and maintains their verticality. Most of the components of SFR are made of 316 L(N)/304 L(N) SS and they are in contact with the liquid-metal sodium which acts as a coolant. The peak operating temperature in SFR is 550°C. However, the self-welding starts at 500°C. To avoid self-welding and galling, hardfacing of the grid plate has become necessary. Nickel based cobalt-free colmonoy 5 has been identified as the hardfacing material due to its lower dose rate by Plasma Transferred Arc Welding (PTAW). This paper is concerned with the measurement and investigations of the effects of the residual stress generated due to thermal cycling on a scale-down physical model of the grid plate. Finite element analysis of the hardfaced grid plate model is performed for obtaining residual stresses using elastoplastic analysis and hence the results are validated. The effects of the residual stresses due to thermal cycling on the hardfaced grid plate model are studied

Development of FPGA Based System for Neutron Flux Monitoring in Fast Breeder Reactors

The project aims to calculate the frequency of the neutron flux by monitoring the signal from neutron detector from shutdown to full power over 10 decades. This neutron flux signal is input to the FPGA based MODULE. A mathematical relationship has been established between the neutron flux (frequency of the neutrons) and the area under the signal. Variable amplitude and occurrence have been accounted for. White noise has also been added and tested for.  VHDL has been used to simplify the otherwise complicated logic gate design. Mathematical modeling has been used as it is the most accurate of the available methods. Index Terms --  Neutron flux monitoring, area, pulse

Thermo Mechanical Analysis of Hard Faced Circular Grid Plate

In this paper, plasma transfer arc welding of hard faced circular grid plate was studied. Hard face deposition made by Plasma Transferred Arc Welding (PTAW) on grid plate at relatively high temperature, generates residual stresses due to differential shrinkage of the molten deposit, process-induced thermal gradients and difference in coefficients of thermal expansion between the deposit and base material. However, the magnitude and distribution of the residual stresses vary depending on the preheat temperature, heat input, deposition process, and the geometry of the component. Finite element analysis of residual stress is performed with commercial FEA package ANSYS 12.0 which includes moving heat source, material deposit, temperature dependent material properties, metal plasticity and elasticity. Coupled thermo-mechanical analysis is done for welding simulation and the element birth and death technique is employed for simulation of filler metal deposition