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Numerical modelling of post-failure behaviors of coal specimens

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 514-531页

作者： Ajeet Yadav Bhaskara Behera Gauri Shankar prasad Singh Sanjay Kumar sharma Department of Mining Engineering Indian Institute of Technology(Banaras Hindu University)VaranasiUttar Pradesh221005India

A modelling approach consisting of best-fit relations to estimate the post-yield strength parameters is presented for simulating post-peak behavior beyond the point of residual strength of coal pillars having different w/h *** model was developed based on back-analysis of the complete stress-strain behavior of specimens belonging to six different Indian coal seams with different w/h ratios of 0.5 *** was found that the simultaneous degradation of the cohesion and friction angle of the Mohr-Coulomb rock material characterizes the post-peak strength behavior of the *** resulting expressions are simplistic as they require parameters that can be easily determined using uniaxial and triaxial compression ***,the developed model was validated by simulating the triaxial tests of coal specimens with different sizes under varying confining stresses and comparing its findings with the published test *** study showed that its implementation in the numerical model could reproduce laboratory-observed mechanical response,deformation behavior,and failure mechanism very closely.

关键词： Strain softening Dilatancy Interface Shape effect Residual strength

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尼泊尔桑可西河流域新格地子流域滑坡评价

Journal of Resources and Ecology 2024年第2期15卷 431-438页

作者： BASNET Bhuwan JOSHI Rajeev sharma Ram prasad SUBEDI Rajan 特里布万大学林业研究所(博卡拉校区) 尼泊尔博卡拉33700 尼泊尔农林大学自然资源管理学院林学系尼泊尔卡塔里56310

山体滑坡是尼泊尔山区的主要灾害,主要是由于其脆弱的地貌、强烈的降雨、不当的土地管理和在修建山区道路过程中没有采取必要的稳定措施所导致的。由于频繁的山体滑坡,下游地区人类的生命财产遭受了巨大损失,并导致生态系统生产力和功... 详细信息

山体滑坡是尼泊尔山区的主要灾害,主要是由于其脆弱的地貌、强烈的降雨、不当的土地管理和在修建山区道路过程中没有采取必要的稳定措施所导致的。由于频繁的山体滑坡,下游地区人类的生命财产遭受了巨大损失,并导致生态系统生产力和功能下降,河道泥沙淤积。土地利用与土地覆被、地形、道路、排水、地质环境和降雨等多种空间因素与滑坡的发生紧密相关,并决定了该地区滑坡的易感性。了解滑坡现象及其引发的相关因素,对于采取适当的预防、控制和恢复措施至关重要。本研究在尼泊尔桑科西河流域的新格地子流域进行,旨在了解滑坡危害、引发的相关因素以及为最大限度地减少可能的危害而采取的最佳预防策略。滑坡评估是通过使用时序谷歌影像和实地调查,对滑坡体进行识别和数字化来进行的。利用GIS软件对滑坡危险性进行评估,编制影响因子图,并对现场观测数据进行分析的基础上,计算了滑坡的规模。此外,在相关家庭的问卷调查(n=60)中,进行目的性抽样,探讨人们对山体滑坡、对生计资产的主要影响因素的看法。并采用Friedman非参数检验评估滑坡对当地人感知的最主要影响因素。根据现场调查,在研究区域的不同位置共调查了46处滑坡体,滑坡总面积为4.77km^(2)。通过使用Friedman检验的比较矩阵分析,本研究确定了滑坡发生的主要原因是农村道路、施工、边坡因素、降雨和土地利用与土地覆被。距离道路200-500 m造成最高比率的滑坡灾害,东南方向坡度30°-45°的山体对滑坡的易感性最高。与其他土地利用相比,因为在林内松软地区修建道路,茂密的森林更易受到山体滑坡的影响。比较道路建设前后滑坡的影响,约80%的受访者认为对滑坡有重要影响。

关键词：滑坡灾害滑坡评估滑坡因素分析

Tuberculosis in kidney transplant candidates and recipients

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World Journal of Transplantation 2024年第3期14卷 59-69页

作者： Pallavi prasad Sourabh sharma Subashri Mohanasundaram Anupam Agarwal Himanshu Verma Department of Nephrology Vardhman Mahavir Medical College and Safdarjung HospitalNew Delhi 110029DelhiIndia Department of Nephrology Prashanth HospitalChennai 600042Tamil NāduIndia

Tuberculosis(TB)is the leading cause of infectious mortality and morbidity in the world,second only to coronavirus disease *** with chronic kidney disease and kidney transplant recipients are at a higher risk of developing TB than the general *** TB is difficult to diagnose in this population due to close *** transplant candidates should be screened for latent TB infection and given TB *** who develop active TB pre-or post-trans-plantation should receive multidrug combination therapy of antitubercular therapy for the recommended duration with optimal dose modification as per glomerular filtration rate.

关键词： Tuberculosis Latent Antitubercular therapy Kidney transplantation Donor Interferon-gamma release assays Tuberculin Rifampicin Isoniazid

Higher Grain-Filling Rate in Inferior Spikelets of Tolerant Rice Genotype Offset Grain Yield Loss under Post-Anthesis High Night Temperatures

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Rice science 2024年第5期31卷 572-586,I0059-I0061页

作者： Nitin sharma Bhupinder SINGH Subbaiyan Gopala KRISHNAN Haritha BOLLINEDI Pranab Kumar MANDAL Milan Kumar LAL Prakash Kumar JHA P.V.Vara prasad Anjali ANAND Division of Plant Physiology Indian Council of Agricultural Research(ICAR)-Indian Agricultural Research Institute(IARI)New Delhi 110012India Division of Environment Science ICAR-IARINew Delhi 110012India Division of Genetics ICAR-IARINew Delhi 110012India ICAR-National Institute for Plant Biotechnology New Delhi 110012India Division of Crop Physiology and Biochemistry ICAR-National Rice Research InstituteCuttack 753006India Department of Plant and Soil Sciences Mississippi State UniversityStarkvilleMS 39762USA Feed the Future Innovation Lab for Collaborative Research on Sustainable Intensification Kansas State UniversityManhattanKS 66506USA Department of Agronomy Kansas State UniversityManhattanKS 66506USA

Increased nighttime respiratory losses decrease the amount of photoassimilates available for plant growth and yield. We hypothesized that the increased respiratory carbon loss under high night temperatures(HNT) could be compensated for by increased photosynthesis during the day following HNT exposure. Two rice genotypes, Vandana(HNT-sensitive) and Nagina 22(HNT-tolerant), were exposed to HNT(4 ℃ above the control) from flowering to physiological maturity. They were assessed for alterations in the carbon balance of the source(flag leaf) and its subsequent impact on grain filling dynamics and the quality of spatially differentiated sinks(superior and inferior spikelets). Both genotypes exhibited significantly higher night respiration rates. However, only Nagina 22 compensated for the high respiration rates with an increased photosynthetic rate, resulting in a steady production of total dry matter under HNT. Nagina 22 also recorded a higher grain-filling rate, particularly at 5 and 10 d after flowering, with 1.5- and 4.0-fold increases in the translocation of ^(14)C sugars to the superior and inferior spikelets, respectively. The ratio of photosynthetic rate to respiratory rate on a leaf area basis was negatively correlated with spikelet sterility, resulting in a higher filled spikelet number and grain weight per plant, particularly for inferior grains in Nagina 22. Grain quality parameters such as head rice recovery, high-density grains, and gelatinization temperature were maintained in Nagina 22. An increase in the rheological properties of rice flour starch in Nagina 22 under HNT indicated the stability of starch and its ability to reorganize during the cooling process of product formation. Thus, our study showed that sink adjustments between superior and inferior spikelets favored the growth of inferior spikelets, which helped to offset the reduction in grain weight under HNT in the tolerant genotype Nagina 22.

关键词： high night temperature inferior grain pasting property radiolabeled sugar superior grain

Evaluation of Rainfall Tendency for the Twentieth Century over Indira Sagar Region in Central India

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American Journal of Climate Change 2024年第1期13卷 47-68页

作者： Rituraj Shukla Deepak Khare Ramesh P. Rudra Priti Tiwari Himanshu sharma prasad Daggupati Pradeep Goel School of Engineering University of Guelph Guelph Canada Department of Water Resources Development and Management Indian Institute of Technology Roorkee India Indira Gandhi Agricultural University Raipur India Department of Civil Engineering Institute of Infrastructure Technology Research and Management (IITRAM) Ahmedabad India

The study investigates long-term changes in annual and seasonal rainfall patterns in the Indira Sagar Region of Madhya Pradesh, India, from 1901 to 2010. Agriculture sustainability, food supply, natural resource development, and hydropower system reliability in the region rely heavily on monsoon rainfall. Monthly rainfall data from three stations (East Nimar, Barwani, and West Nimar) were analyzed. Initially, the pre-whitening method was applied to eliminate serial correlation effects from the rainfall data series. Subsequently, statistical trends in annual and seasonal rainfall were assessed using both parametric (student-t test) and non-parametric tests [Mann-Kendall, Sen’s slope estimator, and Cumulative Sum (CUSUM)]. The magnitude of the rainfall trend was determined using Theil-Sen’s slope estimator. Spatial analysis of the Mann-Kendall test on an annual basis revealed a statistically insignificant decreasing trend for Barwani and East Nimar and an increasing trend for West Nimar. On a seasonal basis, the monsoon season contributes a significant percentage (88.33%) to the total annual rainfall. The CUSUM test results indicated a shift change detection in annual rainfall data for Barwani in 1997, while shifts were observed in West and East Nimar stations in 1929. These findings offer valuable insights into regional rainfall behavior, aiding in the planning and management of water resources and ecological systems.

关键词： Precipitation Parametric Non-Parametric Tests Trend Analysis Serial Correlations

Comprehensive analysis of uncertainty quantification for the^(58)Ni(n,p)^(58)Co reaction cross section

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Chinese Physics C 2024年第9期48卷 170-175页

作者： Mahesh Choudhary Aman sharma Namrata Singh Mahima Upadhyay Punit Dubey A.Gandhi Akash Hingu G Mishra Sukanya De L.S.Danu Ajay Kumar R.G.Thomas Saurav Sood Sajin prasad S.Mukherjee I.N.Ruskov Yu.N.Kopatch A.Kumar Department of Physics Banaras Hindu UniversityVaranasi 221005India Horia Hulubei National Institute of Physics and Nuclear Engineering-IFIN-HH Bucharest 077125Romania Department of Physics The Maharaja Sayajirao University of BarodaVadodara 390002India Nuclear Physics Division Bhabha Atomic Research CentreMumbai 400085India Health Physics Division Bhabha Atomic Research CentreMumbai 400085India Department of Electrical Power Engineering Brno University of TechnologyBrno 61600Czech Republic Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of SciencesSofia 1784Bulgaria Joint Institute for Nuclear Research(JINR) Dubna 141980Russia

In this study,we measured the^(58)Ni(n,p)^(58)Co reaction cross section with neutron energies of 1.06,1.86,and 2.85 *** cross section was measured using neutron activation techniques andγ-ray spectroscopy,and it was compared with cross section data available in the ***,we calculated the covariance matrix of the measured cross section for the aforementioned nuclear *** uncertainties of the theoretical calculation for^(58)Ni(n,p)^(58)Co reaction cross section were calculated via Monte Carlo *** this study,we used uncertainties in the optical model and level density parameters to calculate uncertainties in the theoretical cross *** theoretical calculations were performed by using *** this study,we aim to analyze the effect of uncertainties of the nuclear model input as well as different experimental variables used to obtain the values of reaction cross section.

关键词： ^(58)Ni(n p)^(58)Co reaction γ-ray spectroscopy uncertainty quantification of cross section covariance analysis

Support pressure for circular tunnels in two layered undrained clay

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第1期12卷 135-148页

作者： Bibhash Kumar jagdish prasad Sahoo Department of Civil Engineering National Institute of TechnologyUttarakhand246174India Department of Civil Engineering Indian Institute of TechnologyRoorkee247667India

To estimate the required support pressure for stability of circular tunnels in two layered clay under undrained condition,numerical solutions are developed by performing finite element lower bound limit analysis in conjunction with second-order cone *** support system is assumed to offer uniform internal compressive pressure on its *** the literature,it is known that the stability of tunnels depends on the overburden pressure acting over it,which is a function of undrained cohesion and unit weight of soil,and cover of *** a tunnel is constructed in layered undrained clay,the stability depends on the undrained shear strength,unit weight,and thickness of one layer relative to the other *** the present study,the solutions are presented in a form of dimensionless charts which can be used for design of tunnel support systems for different combinations of ratios of unit weight and undrained shear strength of upper layer to those of lower layer,thickness of both layers,and total soil cover depth.

关键词： Finite elements Layered clay Limit analysis Stability of tunnels

Rutting prediction models for flexible pavement structures: A review of historical and recent developments

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Journal of Traffic and Transportation Engineering(English Edition) 2021年第3期8卷 315-338页

作者： Auinash Kumar Singh jagdish prasad Sahoo Department of Civil Engineering Indian Institute of Technology RoorkeeRoorkee 247667India Department of Civil Engineering Indian Institute of Technology KanpurKanpur 208016India

Rutting is the major distress mode in flexible pavements occurring due to the repeated movement of traffic loading. Deformation in the pavements comprise of both recoverable(elastic) and irrecoverable(plastic) part. Overall deformation occurring in the flexible pavement system due to continuous vehicular movement is contributed from all the components of pavement. A number of empirical models have been proposed by several researchers for analysis and prediction of accumulated rutting in different components of pavement. The accumulated permanent strain has been expressed as the function of the number of load applications and deviator stress applications in most of the models proposed;however, factors such as stress state, moisture content, material type and environmental conditions also impose a significant influence on the permanent deformation characteristics of pavement materials under cyclic loading. In this article, a comprehensive review has been carried out covering every aspect of deformation related to distress occurring in pavements. Important rut models, modeling approaches and modern concepts in the rutting analysis of pavement structures have been presented. In addition to review, fallacy existing in the current design practices related to adaptation of stiffness parameters and negligence of shear strength aspect of subgrade soil has been also presented with the support of literatures.

关键词： Road engineering Permanent deformation Rutting models Resilient modulus Shear strength

Bianchi type V universe with bulk viscous matter and time varying gravitational and cosmological constants

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Research in Astronomy and Astrophysics 2012年第11期12卷 1457-1466页

作者： Prashant Singh Baghel jagdish prasad Singh Department of Mathematical Sciences A. P. S. University

We consider spatially homogeneous and anisotropic Bianchi type V space- time with a bulk viscous fluid source, and time varying gravitational constant G and cosmological term A. The coefficient of bulk viscosity ζ is assumed to be a simple linear function of the Hubble parameter H （i.e. ζ = ζ0 ＋ ζ1H, where ζ0 and ζ1 are constants）. The Einstein field equations are solved explicitly by using a law of varia- tion for the Hubble parameter, which yields a constant value of the deceleration pa- rameter. Physical and kinematical parameters of the models are discussed. The models are found to be compatible with the results of astronomical observations.

关键词： bulk viscosity -- Bianchi V -- relativity: equation of state -- cosmology:cosmological parameters -- miscellaneous