排序方式： 共有36条查询结果，搜索用时 31 毫秒
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Mahmud Sultan Sumana Ferdausi Mahojabin Mohsin Md Khan Md. Hasinur Rahaman 《Natural Hazards》2022,111(2):1863-1884
Natural Hazards - The knowledge of the climate pattern for a particular region is important for taking appropriate actions to alleviate the impact of climate change. It is also equally important... 相似文献
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This study attempts to use the geographic information system (GIS) technique to map and understand the tectonics and crustal structures of Pakistan. Maps of surficial tectonic features and seismological parameters including Moho depth, Pn velocity and Pg velocity are complied. Based on the seismological data-set of the country the earthquake hazard map of Pakistan is also presented by applying regression technique on seismological, geological and topographical parameters. A case study of 8 October 2005 earthquake is used to validate the hazard map. It is envisaged that the developed GIS database would help policy-makers and scientists in natural hazard evaluation, seismic risk assessment and understanding of earthquake occurrences in Pakistan. 相似文献
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Two dimensional ion acoustic shocks in electron-positron-ion (e-p-i) plasma with warm ions, and nonthermal electrons and positrons following the q-nonextensive velocity distribution are studied in the presence of weak transverse perturbations. The kinematic viscosity of warm ions is included for the dissipation in the plasma system. Kadomtsev–Petviashvili–Burgers (KPB) equation is derived by using reductive perturbation method in small amplitude limit and its analytical solution is also presented. The effects of variations of positrons concentration, q-indices of electrons and positrons, ion temperature and kinematic viscosity of ions, on the propagation characteristic of two dimensional shock profile are also discussed. 相似文献
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Mohsin R. Khan 《地震工程与结构动力学》1987,15(8):985-992
A method to generate artificial time-histories from given floor response spectra is presented in this paper. The original method proposed by Levy and Wilkinson1 is modified. New iterative equations are developed, based on extensive computational experimentation, to speed up and stabilize the convergence process. The present approach, when applied to spectra with peaks in the high frequency range (40 to 100 Hz) along with seismic peaks, converges very closely to the target spectra within eight iterations regardless of damping values. The original computer program for synthetic time-history generation was developed on the UNIVAC 1100 series computer. This program was converted to work on the IBM PC. The PC based program ‘MICRO-SEIM’ saves the response spectra generated at each iteration and the final synthetic time-history on the PC diskette. The post processing program reads those saved data from the diskette and plots the spectra and time-history. 相似文献
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Yogendra Tandel Mohsin Jamal Chandresh Solanki Atul Desai Jignesh Patel 《Marine Georesources & Geotechnology》2017,35(4):504-511
Granular piles are frequently used as a method of improving soft grounds as they provide increased bearing capacity and reduce foundation settlements. However, in very soft clayey soils, they may not derive their load-carrying capacity by low confining pressure provided by the surrounding soil. In such circumstances, granular piles may be reinforced with suitable geosynthetic to increase its load-carrying capacity and to reduce excessive bulging. In this study, the performance of small group of geosynthetic-reinforced granular piles (GRGPs) is examined in terms of load-carrying capacity, settlement, and modulus by laboratory model tests. The parameters investigated include modulus of reinforcement material, area replacement ratio (ARR) based on the column diameter and reinforcement length. The results indicated that increasing the modulus of the reinforcement and the ARR based on the column diameter enhances the overall performance of the GRGP group. It was also observed that reinforcement on top portion of the granular pile is sufficient to substantially increase the load-carrying capacity of granular pile group. 相似文献
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Much of the research into multipath detection and mitigation has not considered the carrier phase delay between the line of
sight (LOS) and reflected signals. A new variable referred to as early late phase (ELP) has recently been proposed to exploit
this phase difference. It has been found that in a receiver tracking the L1 GPS signal, the probability of detecting multipath
is lower when the carrier phase difference between the LOS and a reflected signal is an integer multiple of π. Since the pseudorange
error caused by the multipath’s presence is the highest in this case, we propose to exploit the coexistence of another GPS
civilian signal, the L2C. We present an analysis of ELP for the L1 and L2C signals, and a combination of both, for detecting
multipath. The multipath detection performance has been compared using probabilities of false alarm and detection. An ideal
algorithm should have lower probability of false alarm and higher probability of detection. However, it has been found that
using dual-frequency ELP increases both probabilities. Thus, receiver operator characteristics (ROC) curves, and the area
under the ROC curves, have been used for effective comparison. It has been found that the L2C signal individually gives worse
performance than L1 because of its weaker signal strength. However, the combination of L1 and L2C gives the best overall performance,
and thus it can be claimed that ELP using dual-frequency receivers is a more effective approach for detecting multipath. 相似文献