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331.
Failure mechanism of the Yaoba loess landslide on March 5, 2020: the early-spring dry spell in Southwest China 总被引:1,自引:0,他引:1
Wu Kanglin Chen Ningsheng Hu Guisheng Han Zheng Ni Huayong Rahman Mahfuzur 《Landslides》2021,18(9):3183-3195
Landslides - On March 5, 2020, a shallow loess landslide occurred in Yaoba Village, Songpan County, Sichuan Province, posing a severe threat to the lives and properties of 130 villagers. In this... 相似文献
332.
A study was carried out in district Samba of Western Himalayan province of Jammu and Kashmir of India.The data were collected in an interview schedule in personal interview with 180 household heads.The association between the level of fuelwood consumption(low versus high consumption) and different factors,each individually,was investigated using chi-square test of association at 0.001 level of significance.It was found that out of 25 socio-economic,biophysical and alternate fuel factors,15 factors(each individually) significantly influenced the domestic fuelwood consumption.Logistic regression models of alternate fuel use,social,economic and biophysical factors were developed to identify key variables influencing fuelwood consumption levels within each respective category.A composite model was also developed to identify key factors when all variables in all the pre-said categories were considered simultaneously.Surprisingly,in contrast to expectation the model with alternate fuel use did not provide a good fit.The biophysical model also did not provide a good fit.The economic and composite models were the same with equal level of accuracy of predication.This implies that economic aspects,rather than the availability of alternate fuels,dominate fuelwood consumption levels of rural households.Strategies to increase the exposure of the head of household to outside world needs to formulated to reduce the domestic fuelwood consumption levels.Households nearer to state forests are to be educated about efficient use of fuelwood and be encouraged to intensify use of Liquified Petroleum Gas.The wider implications of study are:the availability of alternate fuels is not a necessary condition to decrease household level domestic fuelwood consumption.Economic factors needs to be considered in designing strategies to reduce fuelwood consumption.Increased employment opportunities would increase the opportunity cost of fuelwood collection and this would reduce its use. 相似文献
333.
The Perception and Impact of Natural Hazards on Fishing Communities of Kutubdia Island,Bangladesh 总被引:1,自引:0,他引:1
Natural hazards lead to unexpected and often dire situations for people who have few resources and little control over the environment in which they live. Kutubdia, an island in the southeastern part of Bangladesh, experiences frequent natural hazards that impact the livelihoods of its people and put them in vulnerable situations. The research elaborated here is the result of 300 household surveys collected from persons in Kutubdia's fishing communities. The surveys investigated the perception and consequences of natural hazards on the fishing communities. The results indicated that the experience of natural hazards—cyclones, erosion, and flooding are examples—have increased over the years. Coastal erosion displaced seventy‐two (24 percent) fishers, forcing them to relocate their houses several times and imposing multiple challenges on their lives. Literacy was not associated with perceptions of environmental changes or changes in fishing. However, young fishers—less than forty years of age—perceived that environmental changes had affected fish catch more than their older colleagues. 相似文献
334.
The Gamow-Teller strength distribution function, B(GT), for the odd Z parent 51V, N?Z=5, up to 30 MeV of excitation energy in the daughter 51Ti is calculated in the domain of proton-neutron Quasiparticle Random Phase Approximation (pn-QRPA) theory. The pn-QRPA results are compared against other theoretical calculations, (n, p) and high resolution (d, 2He) reaction experiments. For the case of (d, 2He) reaction the calibration was performed for 0≤E j ≤5.0 MeV, where the authors stressed that within this excitation energy range the ΔL=0 transition strength can be extracted with high accuracy for 51V. Within this energy range the current pn-QRPA total B(GT) strength 0.79 is in good agreement with the (d, 2He) experiment’s total strength of 0.9±0.1. The pn-QRPA calculated Gamow-Teller centroid at 4.20 MeV in daughter 51Ti is also in good agreement with high resolution (d, 2He) experiment which placed the Gamow-Teller centroid at 4.1±0.4 MeV in daughter 51Ti. The low energy detailed Gamow-Teller structure and Gamow-Teller centroid play a sumptuous role in associated weak decay rates and consequently affect the stellar dynamics. The stellar weak rates are sensitive to the location and structure of these low-lying states in daughter 51Ti. The calculated electron capture rates on 51V in stellar matter are also in good agreement with the large scale shell model rates. 相似文献
335.
Gamow-Teller (GT) transitions play a preeminent role in the collapse of stellar core in the stages leading to a Type-II supernova. The microscopically calculated GT strength distributions from ground and excited states are used for the calculation of weak decay rates for the core-collapse supernova dynamics and for probing the concomitant nucleosynthesis problem. The B(GT) strength for 57Zn is calculated in the domain of proton-neutron Quasiparticle Random Phase Approximation (pn-QRPA) theory. No experimental insertions were made (as usually made in other pn-QRPA calculations of B(GT) strength function) to check the performance of the model for proton-rich nuclei. The calculated B(GT) strength distribution is in good agreement with measurements and shows differences with the earlier reported shell model calculation. The pn-QRPA model reproduced the measured low-lying strength for 57Zn better in comparison to the KB3G interaction used in the large-scale shell model calculation. The stellar weak rates are sensitive to the location and structure of these low-lying states in daughter 57Cu. The structure of 57Cu plays a sumptuous role in the nucleosynthesis of proton-rich nuclei. The primary mechanism for producing such nuclei is the rp-process and is believed to be important in the dynamics of the collapsing supermassive stars. Small changes in the binding and excitation energies can lead to significant modifications of the predictions for the synthesis of proton rich isotopes. The ?? +-decay and electron capture (EC) rates on 57Zn are compared to the seminal work of Fuller, Fowler and Newman (FFN). The pn-QRPA calculated ?? +-decay rates are generally in good agreement with the FFN calculation. However at high stellar temperatures the calculated ?? +-decay rates are almost half of FFN rates. On the other hand, for rp-process conditions, the calculated electron capture (?? +-decay) rates are bigger than FFN rates by more than a factor 2 (1.5) and may have interesting astrophysical consequences. 相似文献
336.
Analysis of Pore Pressure and Stress Distribution around a Wellbore Drilled in Chemically Active Elastoplastic Formations 总被引:3,自引:1,他引:3
Drilling in low-permeable reactive shale formations with water-based drilling mud presents significant challenges, particularly
in high-pressure and high-temperature environments. In previous studies, several models were proposed to describe the thermodynamic
behaviour of shale. Most shale formations under high pressure are expected to undergo plastic deformation. An innovative algorithm
including work hardening is proposed in the framework of thermo-chemo-poroelasticity to investigate the effect of plasticity
on stresses around the wellbore. For this purpose a finite-element model of coupled thermo-chemo-poro-elastoplasticity is
developed. The governing equations are based on the concept of thermodynamics of irreversible processes in discontinuous systems.
In order to solve the plastic problem, a single-step backward Euler algorithm containing a yield surface-correction scheme
is used to integrate the plastic stress–strain relation. An initial stress method is employed to solve the non-linearity of the plastic equation. In addition, super convergent patch recovery is used
to accurately evaluate the time-dependent stress tensor from nodal displacement. The results of this study reveal that thermal
and chemical osmosis can significantly affect the fluid flow in low-permeable shale formations. When the salinity of drilling
mud is higher than that of pore fluid, fluid is pulled out of the formation by chemical osmotic back flow. Similar results
are observed when the temperature of drilling mud is lower than that of the formation fluid. It is found that linear elastic
approaches to wellbore stability analysis appear to overestimate the tangential stress around the wellbore and produce more
conservative stresses compared to the results of field observation. Therefore, the drilling mud properties obtained from the
elastoplastic wellbore stability in shales provide a safer mud weight window and reduce drilling cost. 相似文献
337.
Lingyu Wang Michael Rowan-Robinson Issei Yamamura Hiroshi Shibai Rich Savage Seb Oliver Matthew Thomson Nurur Rahman Dave Clements Elysandra Figueredo Tomotsugu Goto Sunao Hasegawa Woong-Seob Jeong Shuji Matsuura Thomas G. Müller Takao Nakagawa Chris P. Pearson Stephen Serjeant Mai Shirahata Glenn J. White 《Monthly notices of the Royal Astronomical Society》2008,387(2):601-615
We present a careful analysis of the point-source detection limit of the AKARI All-Sky Survey in the WIDE-S 90-μm band near the North Ecliptic Pole (NEP). Timeline analysis is used to detect IRAS ( Infrared Astronomy Satellite ) sources and then a conversion factor is derived to transform the peak timeline signal to the interpolated 90-μm flux of a source. Combined with a robust noise measurement, the point-source flux detection limit at signal-to-noise ratio (S/N) > 5 for a single detector row is 1.1 ± 0.1 Jy which corresponds to a point-source detection limit of the survey of ∼0.4 Jy.
Wavelet transform offers a multiscale representation of the Time Series Data ( tsd ). We calculate the continuous wavelet transform of the tsd and then search for significant wavelet coefficients considered as potential source detections. To discriminate real sources from spurious or moving objects, only sources with confirmation are selected. In our multiscale analysis, IRAS sources selected above 4σ can be identified as the only real sources at the Point Source Scales. We also investigate the correlation between the non- IRAS sources detected in timeline analysis and cirrus emission using wavelet transform and contour plots of wavelet power spectrum. It is shown that the non- IRAS sources are most likely to be caused by excessive noise over a large range of spatial scales rather than real extended structures such as cirrus clouds. 相似文献
Wavelet transform offers a multiscale representation of the Time Series Data ( tsd ). We calculate the continuous wavelet transform of the tsd and then search for significant wavelet coefficients considered as potential source detections. To discriminate real sources from spurious or moving objects, only sources with confirmation are selected. In our multiscale analysis, IRAS sources selected above 4σ can be identified as the only real sources at the Point Source Scales. We also investigate the correlation between the non- IRAS sources detected in timeline analysis and cirrus emission using wavelet transform and contour plots of wavelet power spectrum. It is shown that the non- IRAS sources are most likely to be caused by excessive noise over a large range of spatial scales rather than real extended structures such as cirrus clouds. 相似文献
338.
339.
Noor Azlinda Ahmad M. Fernando Z.A. Baharudin M. Rahman V. Cooray Ziad Saleh Joseph R. Dwyer Hamid K. Rassoul 《Journal of Atmospheric and Solar》2010,72(2-3):143-150
In this study, the first electric field pulse of cloud and cloud-to-ground discharges were analyzed and compared with other pulses of cloud discharges. Thirty eight cloud discharges and 101 cloud-to-ground discharges have been studied in this analysis. Pulses in cloud discharges were classified as ‘small’, ‘medium’ and ‘large’, depending upon the value of their relative amplitude with respect to that of the average amplitude of the five largest pulses in the flash. We found that parameters, such as pulse duration, rise time, zero crossing time and full-width at half-maximum (FWHMs) of the first pulse of cloud and cloud-to-ground discharges are similar to small pulses that appear in the later stage of cloud discharges. Hence, we suggest that the mechanism of the first pulse of cloud and cloud-to-ground discharges and the mechanism of pulses at the later stage of cloud discharges could be the same. 相似文献
340.
Abstract The paper discusses aspects of the isotopic composition (tritium and stable isotopes) of precipitation, which was monitored from 2000 to 2003 at 12 stations in Syria. The seasonal variations in δ18O are smaller at the western stations than at the eastern ones due to low seasonal temperature variations. A good correlation between δ2H and δ18O was obtained for each station, and the slopes of the local meteoric water lines are significantly lower than the Global Meteoric Water Line. Values of d-excess decrease from 19‰ at the western stations to 13‰ at the eastern ones, indicating the influence of precipitation generated by air masses coming from the Mediterranean Sea. A reliable altitude effect represented by depletion of heavy stable isotopes (δ18O and δ2H), of about??0.21‰ and??1.47‰ per 100 m elevation, respectively, was observed. Monthly tritium contents in precipitation, and seasonal variations, are less at the western stations than at the eastern ones. The weighted mean tritium values are between 3 and 9 TU, and increase with distance from the Syrian coast by 1 TU/100 km. Citation Al Charideh, A. R. & Abou Zakhem, B. (2010) Distribution of tritium and stable isotopes in precipitation in Syria. Hydrol. Sci. J. 55(5), 832–843. 相似文献