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31.
M. C. Ramadevi S. Seetha Dipankar Bhattacharya B. T. Ravishankar N. Sitaramamurthy G. Meena M. Ramakrishna Sharma Ravi Kulkarni V. Chandra Babu Kumar Brajpal Singh Anand Jain Reena Yadav S. Vaishali B. N. Ashoka Anil Agarwal K. Balaji G. Nagesh Manoj Kumar Dhruti Ranjan Gaan Prashanth Kulshresta Pankaj Agarwal Mathew Sebastian A. Rajarajan D. Radhika Anuj Nandi V. Girish Vivek Kumar Agarwal Ankur Kushwaha Nirmal Kumar Iyer 《Experimental Astronomy》2017,44(1):11-23
Scanning Sky Monitor (SSM) onboard AstroSat is an Xray sky monitor in the soft X-ray band designed with a large field of view to detect and locate transient X-ray sources and alert the astronomical community about interesting phenomena in the X-ray sky. SSM comprises position sensitive proportional counters with 1D coded mask for imaging. There are three detector units mounted on a platform capable of rotation which helps covering about 50% of the sky in one full rotation. This paper discusses the elaborate details of the instrument and few immediate results from the instrument after launch. 相似文献
32.
M N Patil R T Waghmare T Dharmaraj G R Chinthalu Devendraa Siingh G S Meena 《Journal of Earth System Science》2016,125(7):1399-1411
Surface to atmosphere exchange has received much attention in numerical weather prediction models. This exchange is defined by turbulent parameters such as frictional velocity, drag coefficient and heat fluxes, which have to be derived experimentally from high-frequency observations. High-frequency measurements of wind speed, air temperature and water vapour mixing ratio (eddy covariance measurements), were made during the Integrated Ground Observation Campaign (IGOC) of Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) at Mahabubnagar, India (16°44′N, 77°59′E) in the south-west monsoon season. Using these observations, an attempt was made to investigate the behaviour of the turbulent parameters, mentioned above, with respect to wind speed. We found that the surface layer stability derived from the Monin–Obukhov length scale, is well depicted by the magnitude of wind speed, i.e., the atmospheric boundary layer was under unstable regime for wind speeds >4 m s?1; under stable regime for wind speeds <2 m s?1 and under neutral regime for wind speeds in the range of 2–3 m s?1. All the three stability regimes were mixed for wind speeds 3–4 m s?1. The drag coefficient shows scatter variation with wind speed in stable as well as unstable conditions. 相似文献
33.
Titanite occurs as an accessory phase in a variety of igneous rocks, and is known to concentrate geologically important elements
such as U, Th, rare earth element (REE), Y and Nb. The differences in the abundances of the REEs contained in titanite from
granitoid rocks could reflect its response to changes in petrogenetic variables such as temperature of crystallization, pressure,
composition, etc. Widespread migmatization in the granodiorite gneisses occurring to the east of Kolar and Ramagiri schist
belts of the eastern Dharwar craton resulted in the enrichment of the REEs in titanite relative to their respective host rocks.
A compositional influence on the partitioning of REEs between titanite and the host rock/magma is also noticed. The relative
enrichment of REEs in titanite from quartz monzodiorite is lower than that found in the granodioritic gneiss. Depletion of
REE and HFSE (high field-strength elements) abundances in granitic magmas that have equilibrated with titanite during fractional
crystallization or partial melting has been modelled. As little as 1% of titanite present in residual phases during partial
melting or in residual melts during fractional crystallization can significantly lower the abundances of trace elements such
as Nb, Y, Zr and REE which implies the significance of this accessory mineral as a controlling factor in trace element distribution
in granitoid rocks. Sm–Nd isotope studies on titanite, hornblende and whole rock yield isochron ages comparable to the precise
U–Pb titanite ages, invoking the usefulness of Sm–Nd isochron ages involving minerals like titanite. 相似文献
34.
V. Sanil Kumar Glejin Johnson K. K. Dubhashi T. M. Balakrishnan Nair 《Natural Hazards》2013,69(1):509-522
We studied the wave characteristics during the very severe cyclonic storm THANE which crossed the east coast of India between Puducherry and Cuddalore based on waves measured at a location in Bay of Bengal at 14 m water depth. Objective of the paper is to document the highest wave height measured in the nearshore waters of east coast of India. On 29 December 2011, cyclone passed within 77–315 km of the wave measurement location with maximum wind speed of 46.3 m/s (90 knots) and resulted in maximum wave height of 8.1 m. Maximum wave height recorded is 0.54 times the water depth, and the ratio of crest height to wave height of the highest wave recorded is 0.65. Maximum value of significant wave height estimated using the parametric wave model for deep-water conditions is 6.4 m, whereas the measured value is 6 m indicating that parametric wave model estimates the wave height reasonably well (within 8 % error) during the cyclone period. 相似文献
35.
Spectral wave characteristics were studied based on waves measured for 1 year during 2010 off Gangavaram, Bay of Bengal. Maximum wave height of 5.2 m was observed on 19 May 2010 due to the influence of cyclonic storm LAILA. The wave spectrum was single-peaked during 57 % of the time and the double-peaked spectrum observed was mainly swell-dominated. Low-frequency waves (0.05–0.15 Hz) were predominantly from 150° to 180°, whereas high-frequency waves (>0.15 Hz) during November–January were mainly from 90° to 120°, and during July and August from 180° to 210°. Annual average significant wave height was similar to the value (1 m) observed in the eastern Arabian Sea. 相似文献
36.
This work investigates electrolytic treatment and activated carbon adsorption for the removal of melanoidins, the recalcitrant coloring component in fermentation industry wastewaters. A 10% solution of synthetic melanoidins was electrolytically reduced and simultaneously oxidized in an electrolytic cell, thereby altering its reactivity. Adsorption studies using granular activated carbon were conducted using both control and electrolyzed streams. The filterability, surface tension and capillary suction time of the samples were also determined. The reduced melanoidins stream exhibited both a high chemical oxygen demand (COD) removal of 79% and a high color removal of 77% upon activated carbon adsorption. In comparison with the oxidized fraction, the reduced samples displayed enhanced filtration flux as well as decreased capillary suction time, thus indicating better filterability. Furthermore, a decline in surface tension was also observed confirming the decreased hydrophobicity of the reduced melanoidins. 相似文献
37.
38.
Meena Balakrishnan 《Geochimica et cosmochimica acta》2004,68(9):2007-2024
A simple flux balance model with a diffusive, evaporative boundary layer indicates that the time constant (characteristic time) for approach to oxygen isotope steady state in the body fluid of land snails is ∼19 min or less. These comparatively short times support an assumption that the snail’s aragonitic shell is commonly precipitated from a body fluid that is at, or near, isotopic steady state. The model indicates that the steady-state δ18O value of snail shell carbonate depends upon the temperature, relative humidity, δ18O of the input liquid water, and δ18O of ambient water vapor. Model shell δ18O values were calculated for the warm, wet months corresponding to times of snail activity at some European sites. Linear regression of these predicted values against published, measured values yielded the expression: δ18Ocalc = 0.93(±0.13) δ18Omeas −0.9(±0.2), with r2 = 0.65. As indicated by the value of r2, there is scatter in the relationship, but the slope and intercept are close to one and zero, respectively, which lends credence to the model. Therefore, temporal or spatial changes recorded in the δ18O values of land snail shells appear to be selectively seasonal—commonly the warm, wet months—and include the effects of relative humidity.For carbon, the time constant for approach to isotopic steady state in the bicarbonate dissolved in the body fluid of land snails is predicted to be ∼16 min or less. New and published δ13C measurements of aragonite shell and associated organic matter exhibit an overall correlation, but with considerable scatter. As noted by previous workers, 13C-rich dietary “limestone” may account for some of the scatter. Additional scatter, according to the model presented herein, could arise from changes in the proportion of total oxidized carbon that is expelled by the snail as bicarbonate dissolved in body fluid (i.e., effects of relative changes in metabolic rates). These results affirm the need for caution in the interpretation of δ13C values of land snail aragonite shells solely in terms of dietary proportions of C3 and C4 plants. 相似文献
39.
S J Prasad T M Balakrishnan Nair Hasibur Rahaman S S C Shenoi T Vijayalakshmi 《Journal of Earth System Science》2018,127(8):111
A Liquefied Petroleum Gas (LPG) tanker and a chemical tanker collided two nautical miles off Ennore port on 28 January, 2017. Around 196.4 metric tons (MT) of Heavy Furnace Oil (HFO) was spilled and drifted towards the shore. Oil spill drift advisory and prediction was made by Indian National Centre for Ocean Information Services (INCOIS) using General National Oceanic and Atmospheric Administration (NOAA) Operational Modeling Environment (GNOME), an oil spill trajectory model. The trajectory model was forced with analysed and forecasted ocean currents from Global Ocean Data Assimilation System (GODAS) based on Modular Ocean Model 4p1 (GM4p1). It was found that spread of HFO obtained from oil spill trajectory model GNOME, has matched well with the observed spread from Sentinel-1A satellite dataset. However, the spread of the HFO was underestimated by the trajectory model, when forced with forecasted GM4p1 currents. Additional ground truth observation from Indian Coast Guard also corroborates this finding. 相似文献