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61.
We study the influence of different source characteristics (depth, distance, type and azimuth) on the site effect in Acapulco and the Valley of Mexico. Site amplification was estimated by means of spectral ratios (both horizontal-to-vertical spectral ratio and standard spectral ratio techniques were applied) from earthquake recordings at soft and hard sites. In Acapulco, 125 Mexican earthquakes covering a hypocentral range of 7–290 km and a depth range (H) of 3–61 km were analyzed in three different groups of hypocentral distances. In the Valley of Mexico, we estimate site effect at five locations using recordings from shallow-coastal interplate (200?Δ?570 km; H?35 km) and normal-faulting, intermediate-depth inslab (132?Δ?738 km; 32?H?178 km) earthquakes, as well as from teleseismic events. Our results seem to point to negligible dependence of site effects on the source location and type. 相似文献
62.
V. Krishna Prasad Yogesh Kant K. V. S. Badarinath 《Journal of the Indian Society of Remote Sensing》1999,27(3):141-147
Studies related to forest fires are important in the context of trace gas emissions associated with such events. Much of the polar orbiting satellites due to their repetitive cycle have limitation in observing such events and in tropics due to cloud cover, the chance of getting cloud free image during day time becomes difficult. In order to explore the possibilities of using DMSP OLS night time data for monitoring such event, the present study has been under taken in Central Himalayan region of India where extensive fire event has been reported in May/June, 1995. The results of the study suggests the possibility of monitoring such events using DMSP OLS night time data. 相似文献
63.
Sathish Raam Ravichandran Chitra Devi Venkatachalam Mothil Sengottian Sarath Sekar Bhavya Shri Subramaniam Ramasamy Sakthivel Elangovan Siddharth Thorali Sivakumar Shanmuga Sundaram Subramanian 《洁净——土壤、空气、水》2023,51(3):2100305
In the present study, nanocomposite polymeric membranes are fabricated using polyvinyl alcohol (PVA), cellulose acetate (CA) as polymers, and dimethyl sulfoxide (DMSO) as the solvent. To enhance the performance of the membrane, nanoparticles like TiO2, CaO, CdO, and ZrO are added to the polymeric solution and the doped polymeric solution is cast on a glass plate. Nine combinations of membranes are fabricated with two different concentrations (0.1% and 0.2%) of nanoparticles. The basic properties of the membranes such as density, porosity, viscosity, permeability, pure water flux, and water content are studied for the samples. Membrane pore structure and surface properties are identified and it is found that doping nanoparticles on the surface of membranes improve mechanical strength, stability, pore size, etc., allowing the membranes to perform better in extreme industrial-level effluent treatment applications. High-resolution scanning electron microscopy (SEM) shows the homogeneous dispersion of ZrO, TiO2, CaO, and CdO nanoparticles on the surface of the PVA-CA membrane. The doping of nanoparticles on the PVA-CA membrane results in improved mechanical strength and good chemical oxidation stability. In comparison, the PCD-TiO2 sample shows high thermal stability and oxidation stability at high temperatures until 200°C, which has a high potential for treating industrial effluents. 相似文献
64.
Davuluri Srinagesh Shri Krishna Singh Gaddale Suresh Dakuri Srinivas Xyoli Pérez-Campos Gudapati Suresh 《Journal of Seismology》2018,22(3):789-803
The 2017 Guptkashi earthquake occurred in a segment of the Himalayan arc with high potential for a strong earthquake in the near future. In this context, a careful analysis of the earthquake is important as it may shed light on source and ground motion characteristics during future earthquakes. Using the earthquake recording on a single broadband strong-motion seismograph installed at the epicenter, we estimate the earthquake’s location (30.546° N, 79.063° E), depth (H?=?19 km), the seismic moment (M0?=?1.12×1017 Nm, M w 5.3), the focal mechanism (φ?=?280°, δ?=?14°, λ?=?84°), the source radius (a?=?1.3 km), and the static stress drop (Δσ s ~22 MPa). The event occurred just above the Main Himalayan Thrust. S-wave spectra of the earthquake at hard sites in the arc are well approximated (assuming ω?2 source model) by attenuation parameters Q(f)?=?500f0.9, κ?=?0.04 s, and fmax?=?infinite, and a stress drop of Δσ?=?70 MPa. Observed and computed peak ground motions, using stochastic method along with parameters inferred from spectral analysis, agree well with each other. These attenuation parameters are also reasonable for the observed spectra and/or peak ground motion parameters in the arc at distances ≤?200 km during five other earthquakes in the region (4.6?≤?M w ?≤?6.9). The estimated stress drop of the six events ranges from 20 to 120 MPa. Our analysis suggests that attenuation parameters given above may be used for ground motion estimation at hard sites in the Himalayan arc via the stochastic method. 相似文献
65.
Algorithms are derived for constructing five dimensional Kaluza-Klein cosmological space-times in the presence of a perfect fluid source in the framework of f(R,T) gravity theory proposed by Harko et al. (Phys. Rev. D 84:024020, 2011). Starting from the solution of Reddy et al. (Int. J. Theor. Phys 51:3222-3227, 2012b) some classes of new solutions are generated which correspond to accelerating models of the Universe. The physical and kinematical behaviors of the models are studied. 相似文献
66.
Abstract— We conducted Mössbauer spectroscopic studies on the Ghubara meteorite which had been described as at least two‐generation regolith breccia on the macro scale. The isomer shift and quadrupole splitting of the Fe‐Ni part are quite different from those obtained in ordinary chondrites, reflecting shock effects. We observed a large amount of magnetite that may have come from weathering of, primarily, the silicate fraction. We found very similar iron mineralogy in the Densmore meteorite. 相似文献
67.
A technique to generate new exact Bianchi type-III cosmological solutions of massive strings in the presence of magnetic field is presented. Starting from Tikekar and Patel's strings models in the absence and presence of the magnetic field, new solutions are obtained. Some of their physical features are discussed. 相似文献
68.
Abstract— Mössbauer absorption areas corresponding to 57Fe in olivine, pyroxene, troilite, and the metallic phase in ordinary chondrites are shown to exhibit certain systematic behaviors. H chondrites occupy 2 distinct regions on the plot of metallic phase absorption area versus silicate absorption area, while L/LL chondrites fall in a separate region. Similar separation is also observed when pyroxene absorption area is plotted against olivine absorption area. The one‐dimensional plot for the ratio of olivine area to pyroxene area separates L and LL chondrites. Based on these systematics, a newly fallen meteorite at Jodhpur, India is suggested to be an LL chondrite. 相似文献
69.
Exact Bianchi type-VI0 cosmological solutions to Einstein's equations are presented in vacuum and for stiff-matter in the normal gauge for Lyra's geometry and in scalar-tensor theories developed by Saez and Ballester (1985) and Lau and Prokhovnik (1986). Also cosmological solutions are obtained for pure massive strings (p-strings) and for pure geometric strings. The dynamical behaviour of the models have been discussed. 相似文献
70.
Yogesh Kant B. D. Bharath Javed Mallick Clement Atzberger Norman Kerle 《Journal of the Indian Society of Remote Sensing》2009,37(2):201-214
The knowledge of the surface temperature is important to a range of issues and themes in earth sciences central to urban climatology,
global environmental change and human-environment interactions. The study analyses land surface temperature (LST) estimation
using temporal ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) datasets (day time and night time) over
National Capital Territory Delhi using the surface emissivity information at pixel level. The spatial variations of LST over
different land use/land cover (LU/LC) at day time and night time were analysed and relationship between the spatial distribution
of LU/LC and vegetation density with LST was developed. Minimum noise fraction (MNF) was used for LU/LC classification which
gave better accuracy than classification with original bands. The satellite derived emissivity values were found to be in
good agreement with literature and field measured values. It was observed that fallow land, waste land/bare soil, commercial/industrial
and high dense built-up area have high surface temperature values during day time, compared to those over water bodies, agricultural
cropland, and dense vegetation. During night time high surface temperature values are found over high dense built-up, water
bodies, commercial/industrial and low dense built-up than over fallow land, dense vegetation and agricultural cropland. It
was found that there is a strong negative correlation between surface temperature and NDVI over dense vegetation, sparse vegetation
and low dense built-up area while with fraction vegetation cover, it indicates a moderate negative correlation. The results
suggest that the methodology is feasible to estimate NDVI, surface emissivity and surface temperature with reasonable accuracy
over heterogeneous urban area. The analysis also indicates that the relationship between the spatial distribution of LU/LC
and vegetation density is closely related to the development of urban heat islands (UHI). 相似文献