Finding short structural motifs for re-construction of proteins 3D structure

With a view to find useful building blocks (short structural motifs) for reconstruction of 3D structure of proteins, we propose a modified neural gas learning algorithm that we call structural neural gas (SNG) algorithm. The SNG is applied on a benchmark protein data set and its performance is compared with a well known algorithm from the literature (two stage clustering algorithm (TSCA)). The SNG algorithm is found to generate better building blocks compared to TSCA. We have also compared the performance of SNG algorithm with that of a recently reported Incremental Structural Mountain Clustering Method (ISMCM). In general, ISMCM is found to use more building blocks to yield results comparable to that of SNG algorithm. We demonstrate the superiority of SNG over TSCA both in terms of local-fit and global-fit errors using fragments of length five, six, and seven. We also use a graphical means for comparison of the performance of the two algorithms.     

Evaluation of the Effectiveness of Water Management Policies in Bangladesh

Water resources development and management policies initiatives in Bangladesh are primarily driven by the need for sufficient food grain production for the country's teeming population and curtailing the perennial flooding problems. It is therefore necessary to investigate whether or not these objectives are being met. The aim of this study is to evaluate the impacts of past water resources development and management strategies on agriculture, food security, flood management and socio-economic development in Bangladesh. The research is based on the historical data of the relevant parameters of the water resources management over the period 1947–2005. The outcomes of the study demonstrate that past policies and strategies of water development have resulted in significant irrigation expansion, especially through intensified groundwater utilization, which has helped to achieve the country's primary objective of self-sufficiency in food production. However, the provision of safe drinking water and sanitation facilities still remains a challenge in the country. Similarly, the impact of the flood control policies was diverse with success mostly apparent with regard to protection against modest events, while catastrophic, extreme events still effectively defying answer.     

Revisiting Stress Corrosion Cracking of Steel in Caustic Solutions for Developing Cracking Susceptibility Diagrams for Improved Applicability

Stress corrosion cracking tests were conducted using Bayer solutions of different chemistry at different temperatures for extraction of alumina from bauxite ores. The validity of the commonly used caustic cracking susceptibility (CS) diagram for steels exposed to plain caustic solutions was assessed by testing the notched and precracked specimens. This study presents first results toward the development of a model susceptibility diagram for actual Bayer solutions, and for improved applicability of the traditional plain caustic diagram. For mechanistic understanding of caustic cracking, tests were also carried out under imposed electrochemical conditions.     

Phenotypic identification and technological properties of lactic acid bacteria isolated from traditionally processed fish products of the Eastern Himalayas

Sukako maacha, gnuchi, sidra and sukuti are traditional smoked and sun-dried fish products of the Eastern Himalayan regions of Nepal and India. A total of 40 samples of sukako maacha (14), gnuchi (6), sidra (10) and sukuti (10) were collected and were analysed for microbial load. Population of lactic acid bacteria (LAB) as well as aerobic mesophilic counts ranged from 4.7-8.3 to 5.1-8.5 log cfu g(-1), respectively. A total of 189 strains of LAB were isolated from sukako maacha, gnuchi, sidra and sukuti samples, out of which 171 strains were cocci and 15 strains, were heterofermentative lactobacilli. LAB were identified on the basis of phenotypic characters including API system as Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Lactococcus plantarum, Leuconostoc mesenteroides, Enterococcus faecium, Enterococcus faecalis, Pediococcus pentosaceus and Weissella confusa. LAB strains produced a wide spectrum of enzymes. Some strains of LAB showed antagonistic properties against pathogenic strains. None of the strains produced biogenic amines in the method applied. This paper is the first report on the microbial composition, mostly lactic acid bacteria, of traditionally processed fish products of Eastern Himalayas.     

Effect of High-Pressure Processing on Physical, Biochemical, and Microbiological Characteristics of Black Tiger Shrimp (Penaeus monodon)

The effect of high-pressure processing on quality and shelf life of black tiger shrimp was studied. Shrimp was high-pressure processed at selected pressure levels of 100, 270, and 435 MPa for 5 min at room temperature (25?±?2 °C). Changes in physical, biochemical, and microbiological characteristics after processing and during subsequent chilled storage were examined for 35 days. After processing significant (P?<?0.05) increase in moisture content and parallel reduction in protein content was observed. No significant changes were observed in TVB-N and TMA-N levels of shrimp after processing; however, these significantly increased with storage. Whiteness index increased with pressure intensity imparting brighter and mildly cooked appearance. Pressure-induced hardening effect was observed, which showed decreasing trend during storage. The treated samples maintained lower viable counts throughout the storage, thus having better microbial quality than untreated sample. Shelf life was extended to 15 days in shrimp treated at 435 MPa compared with 5 days in untreated sample. Pressure treatment of 435 MPa was found to be most effective in preserving the quality and extending the shelf life of black tiger shrimp.     

MHD non-Darcian mixed convection heat and mass transfer over a non-linear stretching sheet with Soret-Dufour effects and chemical reaction

A study has been carried out to analyze the effects of variable thermal conductivity, Soret (thermal-diffusion) and Dufour (diffusion-thermo) on MHD non-Darcy mixed convection heat and mass transfer over a non-linear stretching sheet embedded in a saturated porous medium in the presence of thermal radiation, viscous dissipation, non-uniform heat source/sink and first-order chemical reaction. The governing differential equations transform into a set of non-linear coupled ordinary differential equations using similarity analysis. Similarity equations are then solved numerically using shooting algorithm with Runge-Kutta Fehlberg integration scheme over the entire range of physical parameters. A comparison with previously published work has been carried out and the results are found to be in good agreement. Graphical presentation of the local skin-friction coefficient, the local Nusselt number and the local Sherwood number as well as the temperature profiles show interesting features of the physical parameters.     

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Frequency regulation in a generation mix having large wind power penetration is a critical issue, as wind units isolate from the grid during disturbances with advanced power electronics controllers and reduce equivalent system inertia. Thus, it is important that wind turbines also contribute to system frequency control. This paper examines the dynamic contribution of doubly fed induction generator (DFIG)-based wind turbine in system frequency regulation. The modified inertial support scheme is proposed which helps the DFIG to provide the short term transient active power support to the grid during transients and arrests the fall in frequency. The frequency deviation is considered by the controller to provide the inertial control. An additional reference power output is used which helps the DFIG to release kinetic energy stored in rotating masses of the turbine. The optimal speed control parameters have been used for the DFIG to increases its participation in frequency control. The simulations carried out in a two-area interconnected power system demonstrate the contribution of the DFIG in load frequency control.     

Impact of viscous dissipation and Dufour on MHD natural convective flow past an accelerated vertical plate with Hall current

The present research work concentrates on viscous dissipation, Dufour, and heat source on an unsteady magnetohydrodynamics natural convective flow of a viscous, incompressible, and electrically conducting fluid past an exponentially accelerated infinite vertical plate in the existence of a strong magnetic field. The presence of the Hall current induces a secondary flow in the problem. The distinguishing features of viscous dissipation and heat flux produced due to gradient of concentration included in the model along with heat source as they are known to arise in thermal-magnetic polymeric processing. The flow equations are discretized implicitly using the finite difference method and solved using MATLAB fsolve routine. Numerical values of the primary and secondary velocities, temperature, concentration, skin friction, Nusselt number, and Sherwood number are illustrated and presented via graphs and tables for various pertinent parametric values. The Dufour effect was observed to strengthen the velocity and temperature profile in the flow domain. In contrast, due to the impact of viscous dissipation, the local Nusselt number reduces. The study also reveals that the inclusion of the chemical reaction term augments the mass transfer rate and diminishes the heat transfer rate at the plate.     

MIMO Channel Capacity and Configuration Selection for Switched Parasitic Antennas

Multiple-input multiple-output (MIMO) systems offer significant enhancements in terms of their data rate and channel capacity compared to traditional systems. However, correlation degrades the system performance and imposes practical limits on the number of antennas that can be incorporated into portable wireless devices. The use of switched parasitic antennas (SPAs) is a possible solution, especially where it is difficult to obtain sufficient signal decorrelation by conventional means. The covariance matrix represents the correlation present in the propagation channel, and has significant impact on the MIMO channel capacity. The results of this work demonstrate a significant improvement in the MIMO channel capacity by using SPA with the knowledge of the covariance matrix for all pattern configurations. By employing the “water-pouring algorithm” to modify the covariance matrix, the channel capacity is significantly improved compared to traditional systems, which spread transmit power uniformly across all the antennas. A condition number is also proposed as a selection metric to select the optimal pattern configuration for MIMO-SPAs.