The deformation response of magnesium based metal matrix composite was investigated by means of hot compression tests. The flow curves were obtained in the temperature and strain rate range of 300-500 °C and 0.001-1 s-1 respectively in order to obtain the processing maps of the studied material and interpreting them on the basis of the dynamic material model. Micro-structural characterization studies conducted on the deformed composite samples, using optical and scanning electron microscopy, revealed a recrystallized grain morphology, debonding of Titanium particles, particle breakage and cracking of the matrix. The observations were performed in order to describe the behavior of the material under hot forming operation in terms of material damage and micro- structural modification.

The present study was carried out to evaluate the antioxidant and antimicrobial activities of a methanol extract of Bauhinia racemosa (MEBR) (Caesalpiniaceae) stem bark in various systems. 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, superoxide anion radical, nitric oxide radical, and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. The antioxidant activity of the methanol extract increased in a concentration-dependent manner. About 50, 100, 250, and 500 µg MEBR inhibited the peroxidation of a linoleic acid emulsion by 62.43, 67.21, 71.04, and 76.83%, respectively. Similarly, the effect of MEBR on reducing power increased in a concentration-dependent manner. In DPPH radical scavenging assays the IC50 value of the extract was 152.29 µg/ml. MEBR inhibited the nitric oxide radicals generated from sodium nitroprusside with an IC50 of 78.34 µg/ml, as opposed to 20.4 µg/ml for curcumin. Moreover, MEBR scavenged the superoxide generated by the PMS/NADH-NBT system. MEBR also inhibited the hydroxyl radical generated by Fenton's reaction, with an IC50 value of more than 1000 µg/ml, as compared to 5 µg/ml for catechin. The amounts of total phenolic compounds were also determined and 64.7 µg pyrocatechol phenol equivalents were detected in MEBR (1 mg). The antimicrobial activities of MEBR were determined by disc diffusion with five Gram-positive, four Gram-negative and four fungal species. MEBR showed broad-spectrum antimicrobial activity against all tested microorganisms. The results obtained in the present study indicate that MEBR can be a potential source of natural antioxidant and antimicrobial agents.

For accurate determination of the three-dimensional structure of atmospheric circulation, it is very important to assimilate every observation from all available sources, especially over the data sparse oceanic regions. During the Indian Ocean Experiment Intensive Field Phase -1999 (INDOEX-IFP 99) several special observations were taken over the Indian Ocean region, which gave an opportunity to study this region more thoroughly. In this study these special observations, along with atmospheric motion vectors that form METEOSAT-5(63ºE), have been assimilated along with other conventional as well as non-conventional observations received at the National Centre for Medium Range Weather Forecasting (NCMRWF) through the Global Telecommunication System (GTS) in its global analyses-forecast system. The aim of this study is to assess the impact of the additional data on the Global Data Assimilation system of NCMRWF as well as to create better initial conditions for its future use in modeling studies. Impact of INDOEX data sets on analyses and subsequent 5-day forecast has been studied on the monthly mean fields. Mean wind field shows the strengthening of trade winds in the lower levels and the strengthening of the wind around sub-tropical anticyclone in the higher levels. It is found that the impact is stronger over the data sparse oceanic region and in the higher levels compared to the lower levels. The impact of these data sets is studied on different initial conditions as well as forecast as part of case studies. Significant positive impacts, specially on analysis, are noticed over those oceanic regions where some well-defined synoptic system persisted.

Para la determinación precisa de la estructura tridimensional de la circulación atmosférica es muy importante asimilar cada observación de todas las fuentes de variables, especialmente sobre las regiones oceánicas escasas de datos. Durante la fase intensiva de campo de 1999 del experimento del Océano índico (INDOEX-IFP 99), se hicieron varias observaciones particulares sobre el Océano Indico que dieron la oportunidad de estudiarlo más exhaustivamente. En este estudio, estas observaciones particulares se han asimilado, junto con otras observaciones convencionales y no convencionales recibidas en el Centro Nacional para el Pronóstico Meteorológico de Rango Medio (NCMRWF), a través del Sistema Global de Telecomunicaciones en su sistema de análisis global de pronóstico. El propósito de este estudio es determinar el impacto de los datos adicionales sobre el Sistema Global de Asimilación de Datos del NCMRWF, así como generar mejores condiciones iniciales para su uso futuro en estudios de modelado. Se ha estudiado el impacto de los grupos de datos en análisis y pronósticos subsecuentes de 5 días en los campos medios mensuales. El campo medio de viento muestra el fortalecimiento de las tendencias de los vientos en los niveles bajos y el fortalecimiento del viento alrededor del anticiclón subtropical en los niveles altos. Se ha encontrado que el impacto es mayor sobre las regiones oceánicas escasas de datos y en los niveles altos en comparación con los niveles bajos. Se ha estudiado el impacto de estos grupos de datos sobre diferentes condiciones iniciales así como sobre el pronóstico. Se han observado impactos significativos sobre aquellas regiones oceánicas donde persisten sistemas sinópticos bien definidos.