Analysis of thermo-hydrologic-mechanical impact of repository for high-level radioactive waste in clay host formation: an Indian reference disposal system     

Avi Dutt  M. S. Saini  T. N. Singh  A. K. Verma  R. K. Bajpai 《Environmental Earth Sciences》2012,66(8):2327-2341

In our study, a coupled hydrologic-mechanical analysis is done of the excavation damaged zone, before the emplacement of nuclear waste. This is followed by a coupled thermal-hydrologic-mechanical analysis to evaluate the impact of nuclear waste repository in porous water containing rock mass. This analysis has been under taken in accordance with the Indian reference disposal system. The paper considers the changes in pore pressure and stresses due to excavation of disposal holes. A critical study of rock mass permeability, porosity, thermally induced stresses, strains, and temperature distribution after the emplacement of nuclear spent fuels in disposal holes has also been done. Coupling to the mechanical constitutive equations is done via ??effective?? normal strain rates.  相似文献   

Is there supernova evidence for dark energy metamorphosis?   总被引：1，自引：0，他引：1  

Ujjaini Alam  Varun Sahni  Tarun Deep Saini  A. A. Starobinsky 《Monthly notices of the Royal Astronomical Society》2004,354(1):275-291

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On the validity of series expansion being used for the position of a point on a Roche equipotential     

A. K. Lal  S. Saini  C. Mohan  V. P. Singh 《Astrophysics and Space Science》2007,310(3-4):317-320

The concept of Roche equipotentials has been frequently used in literature to study the problems of rotating stars and stars in binary systems. However in spite of using this simplifying concept, it is still not possible to express the position of a point in the potential field of such a system in a closed analytic form. In order to carry out further analytic studies, Kopal (Adv. Astron. Astrophys. 9:1–65, 1972), therefore, developed a series expansion for it. The series expansion of Kopal has often been used in the analysis of the problem of equilibrium structure and the periods of oscillations of rotating stars and stars in binary systems, but its validity and convergence has not been analytically established. It is important that this aspect of the problem is checked so that one is sure of the correctness of subsequent analysis and results based on this series expansion. In the present brief note, we have addressed ourselves to this problem and validated the correctness of the numerical results obtained through the use of this series expansion.  相似文献   

A regularized free-form estimator for dark energy     

Tarun Deep Saini 《Monthly notices of the Royal Astronomical Society》2003,344(1):129-133

We construct a simple, regularized estimator for the dark energy equation of state by using the recently introduced linear response approximation. We show that even a simple regularization substantially improves the performance of the free-form fitting approach. The use of the linear response approximation allows an analytical construction of the maximum likelihood estimator, in a convenient and easy to use matrix form. We show that, in principle, such regularized free-form fitting can give us an unbiased estimate of the functional form of the equation of state of dark energy. We show the efficacy of this approach on simulated SuperNova Acceleration Probe class data, but it is easy to generalize this method to include other cosmological tests. We provide a possible explanation for the sweet spots seen in other reconstruction methods.  相似文献   

Impact of geohydrology and neotectonic activity on radon concentration in groundwater of intermontane Doon Valley, Outer Himalaya, India   总被引：1，自引：0，他引：1  

V. M. Choubey  S. K. Bartarya  N. K. Saini  R. C. Ramola 《Environmental Geology》2001,40(3):257-266

 Radon concentration was measured in 133 water samples from tubewells, handpumps, dug wells and springs of the Doon Valley, Outer Himalaya, India. The observed radon values were found to vary from 10 to 154 Bq/l whereas radium in selected water samples varied from 0.11 to 0.75 Bq/l. Three different clusters of high radon values were observed in the north-western, central and south-eastern parts of the Doon Valley. These clusters were found to be associated with tectonics (thrust/fault) and associated uranium mineralization in the area. In general, radon concentration in groundwater was found to be positively correlated with the depth of the wells, whereas no significant correlation was observed between radon concentration in groundwater and the water temperature, pH value, conductivity and altitude of the water samples. An attempt has also been made to determine the nature and extent of aquifers in the Doon Valley on radon concentration in groundwater. The variation in radon concentration within the groundwater of the study area was found to be controlled by the neotectonic activity and geohydrological processes that occur in the area. The impact of these activities on radon concentration in groundwater are discussed. Received: 17 September 1999 · Accepted: 11 April 2000  相似文献   

1960-2016年秦岭—淮河地区热浪时空变化特征及其影响因素   总被引：4，自引：3，他引：1  

李双双  延军平  杨赛霓  胡书山  赵怡 《地理科学进展》2018,37(4):504-514

基于134个气象站点1960-2016年逐日最高温和相对湿度数据,辅以趋势分析、空间分析和相关分析等方法,对秦岭—淮河地区热浪时空变化特征进行分析,探讨了赤道东太平洋海温异常与热浪变化的相关关系。结果表明：①近57年秦岭—淮河地区热浪呈现“非线性、非平稳和阶段性”的变化过程,年代变化可分为3个阶段：1960-1972年热浪呈现东西分异,分界线大致位于112°E,以东地区热浪异常偏多,以西地区则“高低交替”波动;1973-1993年热浪维持“低位波动”,并在20世纪80年代中期呈现快速增加;1994-2016年,关中平原、秦巴山区、巫山山区和四川盆地热浪维持“高位波动”,黄河下游、淮河平原和长江下游热浪则经历从“相对偏多”向“相对偏少”的转变;②在影响因素方面,最高温波动变化是秦岭—淮河地区热浪频次年代变化的主导因素,相对湿度变化的影响相对较弱;③近57年来关中平原热浪年代变化与赤道太平洋西部海温异常关系更为密切,长江流域与东部海温异常关系更为密切;对于黄河下游和秦巴山区的热浪变化与不同分区赤道太平洋海温异常关系均较弱。  相似文献   

Equilibrium Structure of Rotationally and Tidally Distorted Prasad Model Including the Effect of Mass Variation Inside the Star     

Seema Saini  A. K. Lal  Sunil Kumar 《Astrophysics》2014,57(1):119-129

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Rapid Determination of Trace and Ultra Trace Level Elements in Diverse Silicate Rocks in Pressed Powder Pellet Targets by LA‐ICP‐MS using a Matrix‐Independent Protocol     

Pulok K. Mukherjee  Param P. Khanna  Naresh K. Saini 《Geostandards and Geoanalytical Research》2014,38(3):363-379

A simple, single sample preparation involving pressed rock powder pellets was utilised to determine the trace and ultra trace abundances of petrogenetically important elements including high field‐strength elements and REEs by laser ablation‐ICP‐MS. One of the elements predetermined by XRF spectrometry served as an internal standard. The influence of sample preparation parameters (grain size, pellet compactness and amount of binding media) on analytical performance was also investigated, including sample homogeneity issues at the laser sampling scale. Line scanning with a high repetition frequency (20 Hz) and large beam diameter (200 μm) ensured ablation from a larger sample surface area, eliminating issues related to sample heterogeneity. A median grain size of about 10 μm for silicate rock powders was found to be sufficiently representative at this scale of laser sampling. Granitic rocks or samples containing resistant minerals such as zircon needed extra grinding to achieve grain sizes down to < 5 μm for better precision for elements that are concentrated in these phases. Using ¹³⁷Ba as an internal standard, reasonable accuracies within 15–20% for most of the high mass trace elements were achieved; in the case of low mass elements, it may deviate up to 40%. Precision of measurements rarely exceeded 15% RSD.  相似文献   

Preparation and Characterisation of Two Geochemical Reference Materials: DG‐H (Granite) and AM‐H (Amphibolite) from the Himalayan Orogenic Belt     

Naresh K. Saini  Param P. Khanna  Pulok K. Mukherjee  Kishor K. Purohit 《Geostandards and Geoanalytical Research》2014,38(1):111-122

Two geochemical reference materials of Himalayan origin named DG‐H (a granite) and AM‐H (an amphibolite) prepared by the Wadia Institute of Himalayan Geology Dehradun are described. Both samples were collected from the NW Himachal Himalaya in India. With the participation of analysts from more than forty international laboratories, element determination data collected during the past 10 years for characterisation of the samples was processed to assign working values using statistical procedures in use for this purpose. Earlier work published on these samples is incorporated in the present communication making it an updated document. The typical chemical and petrological characteristics of these two samples may prove useful for method validation and calibration of analytical instruments used for analysing similar rock types, and for widening the analytical range of several analytical methods used for geochemical analysis.  相似文献