Time-dependent seismicity analysis in the Northwest Himalaya and its adjoining regions     

P. Chingtham  R. B. S. Yadav  S. Chopra  Arabind Kumar Yadav  A. K. Gupta  P. N. S. Roy 《Natural Hazards》2016,80(3):1783-1800

  相似文献   

Active and break events of Indian summer monsoon during 1901–2014     

D. S. Pai  Latha Sridhar  M. R. Ramesh Kumar 《Climate Dynamics》2016,46(11-12):3921-3939

  相似文献   

Detrital zircon U–Pb geochronology of a Cenozoic foreland basin in Northeast India: Implications for zircon provenance during the collision of the Indian and Asian plates     

Upendra Baral  Ding Lin  Tapos Kumar Goswami  Mondip Sarma  Muhammad Qasim  Devojit Bezbaruah 《地学学报》2019,31(1):18-27

Geochronology is useful for understanding provenance, and while it has been applied to the central and western Himalaya, very little data are available in the eastern Himalaya. This study presents detrital zircon U–Pb ages from the late Palaeocene–Eocene Yinkiong Group in NE India. The samples are from the late Palaeocene to early Eocene Lower Yinkiong Formation, and the Upper Yinkiong Formation deposited during the early to mid‐Eocene within the Himalayan foreland basin. The U–Pb ages of the detrital zircon within the Lower Yinkiong Formation are older than late Palaeozoic, with a cratonic and early Himalayan Thrust Belt affinity, whereas the Cenozoic grains in the Upper Yinkiong Formation indicate a Himalayan Thrust Belt source and possibly a granitic body within the Asian plate. The shift of the sources and the changes in the foreland basin system strongly suggest that the India–Asia collision in the Eastern Himalaya began before or immediately after the deposition of the Upper Yinkiong Formation, i.e., within the early Eocene (c. 56 to 50 Ma).  相似文献   

Stability analysis of multi-directional anchored rock slope subjected to surcharge and seismic loads     

Sanjay Kumar Shukla  Md. Monir Hossain 《Soil Dynamics and Earthquake Engineering》2011,31(5-6):841-844

More than one set of anchors with different orientations can be an economical solution to completely stabilize the rock slope. In this note, a general analytical expression for the factor of safety of a multi-directional anchored rock slope (MDARS) against plane failure is derived, incorporating most of the practically occurring destabilizing forces under surcharge and seismic loading conditions. Several special cases of this expression are found to be similar to those reported in the literature. A graphical presentation shows that for any specific inclination of one set of anchors to the normal at failure plane, the variation in the inclination of the second set of anchors to the normal at failure plane, when greater than approximately 60°, does not cause a significant change in the factor of safety of the MDARS.  相似文献   

Assessment of ecological disturbance in the mangrove forest of Sundarbans caused by cyclones using MODIS time-series data (2001–2011)     

Dibyendu Dutta  Prabir Kumar Das  Soubhik Paul  Jaswant Raj Sharma  Vinay Kumar Dadhwal 《Natural Hazards》2015,79(2):775-790

  相似文献   

The M w 6.9 Sikkim–Nepal earthquake of September 2011: a perspective for wrench faulting in the Himalayan thrust zone     

N. Purnachandra Rao  V. M. Tiwari  M. Ravi Kumar  Pinki Hazarika  Dipankar Saikia  R. K. Chadha  Y. J. Bhaskar Rao 《Natural Hazards》2015,77(1):355-366

  相似文献   

A quantum chemical study on the formation of ethanimine (CH<Subscript>3</Subscript>CHNH) in the interstellar ice     

Keshav Kumar Singh  Shivani  Poonam Tandan  Alka Misra 《Astrophysics and Space Science》2018,363(10):213

Ethanimine (CH₃CHNH) is an important prebiotic molecule since it is a precursor of amino acid \(\alpha \)-alanine in Strecker synthesis. Two isomers (E and Z) of ethanimine were detected in the molecular cloud Sagittarius B2 north during GBT-PRIMOS survey. A possible radical-molecule reaction pathway has been proposed for the formation of ethanimine in the interstellar medium (ISM) from some previously detected interstellar molecules like methylene (both triplet CH₂ (³B₁) and singlet CH₂ (¹A₁)) and methyenimine (CH₂NH). The mechanism has been studied in the gas phase and in water ice with the help of density functional theory at B2PLYPD/6-311++G (2d, p) level of theory. It is observed that E-ethanimine forms efficiently in gas phase but ice reactions are favorable only in the hot core of molecular clouds. Same is true for the formation of Z-ethanimine which forms only at the surface of water cluster as the height of entrance barrier for formation of Z-ethanimine is similar to that of E-ethanimine. Isomerization from E to Z form is also studied and found to be forbidden due to large entrance barrier. Out of the two reaction system CH₂ (³B₁) + CH₂NH and CH₂ (¹A₁) + CH₂NH, later is more favorable then the former one due to the small entrance barrier. Still, much of the detected abundance of ethanimine comes from the reaction of CH₂ (³B₁) with CH₂NH as since CH₂ (¹A₁) has very low abundance compared to the CH₂ (³B₁) in ISM. The proposed pathway seems to be a promising candidate for the ethanimine formation in ISM.  相似文献   

Halo orbit of regularized circular restricted three-body problem with radiation pressure and oblateness     

Vineet K. Srivastava  Jai Kumar  Padmdeo Mishra  Badam Singh Kushvah 《Journal of Astrophysics and Astronomy》2018,39(5):63

In this paper, computation of the halo orbit for the KS-regularized photogravitational circular restricted three-body problem is carried out. This work extends the idea of Srivastava et al. (Astrophys. Space Sci. 362: 49, 2017) which only concentrated on the (i) regularization of the 3D-governing equations of motion, and (ii) validation of the modeling for small out-of-plane amplitude (\(A_z =110000\) km) assuming the third-order analytical approximation as an initial guess with and without differential correction. This motivated us to compute the halo orbits for the large out-of-plane amplitudes and to study their stability analysis for the regularized motion. The stability indices are described as a function of out-of-plane amplitude, mass reduction factor and oblateness coefficient. Three different Sun–planet systems: the Sun–Earth, Sun–Mars and the Sun–Jupiter are chosen in this study. Stable halo orbits do not exist around the \(L_{1}\) point, however, around the \(L_{2}\) point stable halo orbits are found for the considered systems.  相似文献   

Systematic analysis of low/hard state RXTE spectra of GX 339–4 to constrain the geometry of the system     

Kalyani Bagri  Ranjeev Misra  Anjali Rao  Jagdish Singh Yadav  Shiv Kumar Pandey 《天文和天体物理学研究(英文版)》2018,(5)

One of the popular models for the low/hard state of black hole binaries is that the standard accretion disk is truncated and the hot inner region produces, via Comptonization, hard X-ray flux.This is supported by the value of the high energy photon index, which is often found to be small,～ 1.7( 2), implying that the hot medium is starved of seed photons. On the other hand, the suggestive presence of a broad relativistic Fe line during the hard state would suggest that the accretion disk is not truncated but extends all the way to the innermost stable circular orbit. In such a case, it is a puzzle why the hot medium would remain photon starved. The broad Fe line should be accompanied by a broad smeared reflection hump at ～ 30 ke V and it may be that this additional component makes the spectrum hard and the intrinsic photon index is larger, i.e. 2. This would mean that the medium is not photon deficient, reconciling the presence of a broad Fe line in the observed hard state. To test this hypothesis,we have analyzed the RXTE observations of GX 339–4 from the four outbursts during 2002–2011 and identify observations when the system was in the hard state and showed a broad Fe line. We have then attempted to fit these observations with models, which include smeared reflection, to understand whether the intrinsic photon index can indeed be large. We find that, while for some observations the inclusion of reflection does increase the photon index, there are hard state observations with a broad Fe line that have photon indices less than 2.  相似文献   

Comparative study of neural network,fuzzy logic and linear transfer function techniques in daily rainfall‐runoff modelling under different input domains     

Anil Kumar Lohani  N. K. Goel  K. K. S. Bhatia 《水文研究》2011,25(2):175-193

This paper compares artificial neural network (ANN), fuzzy logic (FL) and linear transfer function (LTF)‐based approaches for daily rainfall‐runoff modelling. This study also investigates the potential of Takagi‐Sugeno (TS) fuzzy model and the impact of antecedent soil moisture conditions in the performance of the daily rainfall‐runoff models. Eleven different input vectors under four classes, i.e. (i) rainfall, (ii) rainfall and antecedent moisture content, (iii) rainfall and runoff and (iv) rainfall, runoff and antecedent moisture content are considered for examining the effects of input data vector on rainfall‐runoff modelling. Using the rainfall‐runoff data of the upper Narmada basin, Central India, a suitable modelling technique with appropriate model input structure is suggested on the basis of various model performance indices. The results show that the fuzzy modelling approach is uniformly outperforming the LTF and also always superior to the ANN‐based models. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献