Ravindra Pratap Singh

Low frequency dielectric relaxation in lightly doped VO2 single crystals

Abstract The relative effects of intrinsic and extrinsic defects on the dielectric relaxation of VO2 crystals have been investigated by measurement of the dielectric parameters of undoped crystals and crystals doped with Ti, Cr and Al. Measurements have been made in the temperature range 77–250 K and the frequency range 50–100 kHz. The dielectric data is described by a Cole-Cole distribution function with a distribution parameter α ≅ 0.45 which decreases with increasing temperature. However, the distribution of activation energies g(E) derived from α is almost independent of temperature. The overall dielectric relaxation behaviour is determined primarily by the intrinsic defect structure of VO2, and the effect of impurities is observed only in changes in the low frequency limiting (static) value of the dielectric constant. The same transport mechanism is found to determine the dc conductivity and the dielectric relaxation and evidence is presented that the dielectric relaxation is of dipolar origin.

GIS-based morpho-tectonic studies of Alaknanda river basin: a precursor for hazard zonation

Abstract Alaknanda river basin is considered to be tectonically active where damaging earthquakes and landslides have occurred. The whole basin was divided into 8 sub-basins to carry out morphometric analyses, hypsometric integral (HI) analysis and valley floor width to valley height ratio (Vf) factor. The sub-basins 2 and 3 show that they are highly active, because of the higher values of bifurcation ratio, stream frequency asymmetric factor, and lower values of form factor, elongation ratio and circulatory ratio. In these areas, HI values are very low indicating that the landscape is highly eroded, deeply dissected and tectonically active. The result obtained from Vf was similar which classified both these basins as highly active. Morphometric analysis, HI and Vf analyses along with structural map of study area are used to prepare morpho-tectonic map classifying the whole area into very high, high, moderate and low zones of tectonic activity. This map clearly indicates that the areas near MCT II (Munsiari Thrust), MCT III (Ramgarh Thrust) and North Almora Thrust are tectonically very active which fall in sub-basins 2, 3, 4 and parts of 5. Various locations such as Chamoli, Birahi, Pipalkoti, Rudraprayag, etc. are situated in these zones where many earthquakes and landslides occur every year. Moreover, the data plotted for earthquakes and landslides occurrences are consistent with morpho-tectonic map and can be used as a precursor for demarcation of natural hazard vulnerable zones.

Liquefaction potential evaluation for subsurface soil layers of Delhi region

The study area Delhi is second most populous city and third largest urban area in the world. Though the area lies in seismic high damage risk zone, number of high rise building and construction of mega structure at several sites of the city increase rapidly. In this study field Standard Penetration Test (SPT) values of soil collected from 750 boreholes data were analyzed to identify liquefiable sub-surface soil layers. Finally, liquefaction susceptible sub-surface maps of the region at various depth (20 m, 15 m, 12 m, 9 m, 6 m and 3 m) from ground level is prepared. The outcome of this study will be useful input for preliminary foundation and designing of earthquake resistant high rise building and seismic microzonation studies of Delhi.

Maximum α-Amylase Production by Molecular and Biochemical Characterized Soil Microorganism

The present investigation was undertaken with an aim to produce α-amylase in cost effective way keeping its market potential into consideration. This result obtained from present study prove that Bacillus licheniformis is the maximum α-amylase producing strain isolated from soil under suitable conditions. This study will very helpful for upcoming researchers to uncover the various aspect of enzyme production by microorganism. The present investigation was undertaken with an aim to produce higher amount of amylase with pure compounds in submerged fermentation. To screen the isolates for promising α-amylase producing capability and one of the most promising isolate is further scale up. Amylase constitutes a class of industrial enzymes having approximately 20% of the enzyme market. α-amylase has found its application in a range of industries including food, brewing, distilling industry, textile, paper pharmaceutical and bioconversion of solid waste etc. Microorganism used in present investigation, isolated from rhizospheric regions of giant newar variety of Raphanus sativus grown in district Jaunpur, (Uttar Pradesh) India. A total of 30 natural isolates were scanned for α-amylase activity out of which 20 isolates were biochemically characterized. Based on ribotyping all the isolates were identified and one of the most promising amylase producer, i.e., Bacillus licheniformis was finally selected for further studies. The experiments were carried out in triplicates and mean value was taken. Nutritional source such as carbon and nitrogen sources were optimized for the production of α-amylase in free cell condition. Maximum α-amylase production was observed at 24 h. of incubation. Three different types of media such as Semi-synthetic, complex media I and complex media II tested and various parameters were optimized for enhance the alpha-amylase yield. It was found that identified soil microorganism Bacillus licheniformis is the best strain for α-amylase production and complex media-I gave maximum yield.