Geochemistry and petrogenesis of Proterozoic granitic rocks from northern margin of the Chotanagpur Gneissic Complex (CGC)   总被引：1，自引：0，他引：1  

Bhupendra S Yadav  Nishchal Wanjari  Talat Ahmad  Rajesh Chaturvedi 《Journal of Earth System Science》2016,125(5):1041-1060

This study presents the geochemical characteristics of granitic rocks located on the northern margin of Chotanagpur Gneissic Complex (CGC), exposed in parts of Gaya district, Bihar and discusses the possible petrogenetic process and source characteristics. These granites are associated with Barabar Anorthosite Complex and Neo-proterozoic Munger–Rajgir group of rocks. The granitic litho-units identified in the field are grey, pink and porphyritic granites. On the basis of geochemical and petrographic characteristics, the grey and pink granites were grouped together as GPG while the porphyritic granites were named as PG. Both GPG and PG are enriched in SiO₂, K₂O, Na₂O, REE (except Eu), Rb, Ba, HFSE (Nb, Y, Zr), depleted in MgO, CaO, Sr and are characterised by high Fe* values, Ga/Al ratios and high Zr saturation temperatures (GPG_avg～ 861 ^°C and PG_avg～ 835 ^°C). The REE patterns for GPG are moderately fractionated with an average (La/Yb)_N～ 4.55 and Eu/Eu* ～ 0.58, than PG which are strongly fractionated with an average (La/Yb)_N～ 31.86 and Eu/Eu* ～ 0.75. These features indicate that the granites have an A-type character. On the basis of geochemical data, we conclude that the granites are probably derived from a predominant crustal source with variable mantle involvement in a post-collisional setting.  相似文献   

Study of Cosmic Ray Intensity in Relation to the Interplanetary Magnetic Field and Geomagnetic Storms for Solar Cycle 23     

Hema Kharayat  Lalan Prasad  Rajesh Mathpal  Suman Garia  Beena Bhatt 《Solar physics》2016,291(2):603-611

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Urban growth and quality of life: inter-district and intra-district analysis of housing in NCT-Delhi, 2001–2011–2020     

Sharma  Madhuri  Abhay  Rajesh Kumar 《GeoJournal》2022,87(4):797-819

One out of three people in India is urban. In 2011, there were about 53 urban agglomerations larger than 1 million population as against only 35 in 2001. Much of this urban expansion has been occurring in the country’s largest metropolises including the National Capital Territory of Delhi which has expanded horizontally and vertically both. This has also added to overall decline in its already dilapidated housing stock and quality of life. Delhi, a historical hub for regional, national, and international commerce, and a place for the socio-political elites, has failed to provide basic life amenities to its average citizens. This research critiques the (un)sustainable elements of Delhi’s urbanization and concomitant decline in basic amenities pertaining to quality-of-life by examining the growth and expansion of its urban-built-up areas during 2001–2011–2020 and provides nuanced insights into its ‘livability’ by examining select quality-of-life attributes. The LANDSAT imageries for 2010 and 2020 are used to measure NDB-Index that assesses its built-up area and change, which are later corroborated with Census household data to examine change in its ‘livable’ and ‘dilapidated’ housing structures. Significant sub-regional disparity exists in the availability of good and livable homes, with almost 20–30% of several districts still without drinking water source inside premises. However, significant progress is also noted for basic amenities like lighting, latrine and bathing facilities, and majority of Delhi’s built-up area has expanded along newer developments and transportation corridors. This calls for goal-oriented strategic interventions by policymakers to help achieve the SDG-11 on Sustainable Cities.

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Harnessing spatio‐temporal patterns in data for nominal attribute imputation     

Rajesh Chittor Sundaram  Elham Naghizade  Renata Borovica‐Gajic  Martin Tomko 《Transactions in GIS》2020,24(4):1001-1032

Missing data in Volunteered Geographic Information (VGI) are an unavoidable consequence of data collection by non‐experts, guided by only vague and informal mapping guidelines. While various Missing Value Imputation (MVI) techniques have been proposed as data cleansing strategies, they have primarily targeted numerical data attributes in non‐spatial databases. There remains a significant gap in methods for imputing nominal attribute values (e.g., Street Name) in map databases. Here, we present an imputation algorithm called the Membership Imputation Algorithm (MIA), targeting spatial databases and enabling imputation of nominal values in spatially referenced records. By targeting membership classes of spatial objects, MIA harnesses spatio‐temporal characteristics of data and proposes efficient heuristics to impute the class name (i.e., a membership). Experimental results show that the proposed algorithm is able to impute the membership with high levels of accuracy (over 94%) when assigning Street Name(s), across highly diverse regional contexts. MIA is effective in challenging spatial contexts such as street intersections. Our research serves as a first step in highlighting the effectiveness of spatio‐temporal measures as a key driver for nominal imputation techniques.  相似文献   

Nonlinear Dynamics of Kinetic Alfvén and Whistler Waves in the Solar Wind     

Rajesh Kumar Rai  Swati Sharma  R. P. Sharma 《Solar physics》2017,292(3):42

In this article we investigate the nonlinear dynamics of 3D kinetic Alfvén waves (KAWs) and quasi-transverse weak whistler waves in a magnetized plasma. We have studied the problem numerically to examine the transient evolution of localized structures of 3D KAWs and whistler waves. The nonlinearity arises as a result of ponderomotive effects associated with 3D KAWs; consequently, the background density modifies. The weak whistler waves propagating in this modified density are localized and amplified. To improve our insight into the basic physics behind the formation of these localized structures, we have also solved the system semi-analytically. The power spectra show a Kolmogorov scaling (with a power of \(-5/3\)) in the inertial range that lies above the ion gyroradius. Below this scale, dispersive effects start to appear, and the power spectrum follows a steeper scaling (?2 to ?4). Our results show the important role that KAWs and whistler waves play in the energy cascading from larger to smaller scales. The results are consistent with the solar wind observations by the Cluster spacecraft.  相似文献   

Wall building stiffness and strength effect on content sliding in Wellington seismic conditions          下载免费PDF全文

Trevor Z. Yeow  Gregory A. MacRae  Rajesh P. Dhakal 《地震工程与结构动力学》2017,46(6):1023-1042

A numerical study of unobstructed content sliding within several low‐to‐midrise reinforced concrete cantilever wall buildings designed to Wellington conditions in New Zealand is performed to validate the belief that increasing a building's strength and/or stiffness would result in more severe sliding response. It was shown that contents within stronger buildings experienced larger sliding response. If the building was designed to be strong, the sliding response of contents with a friction coefficient of 0.1 was smaller in stiffer buildings compared with those in flexible buildings. However, the trends start reversing with an increase in friction coefficient or a decrease in building strength. Overall, content sliding is not necessarily more severe in stiffer buildings, and in many cases, the opposite is true. This study's findings were compared against an existing parametric equation for estimating the maximum sliding displacement. This equation, which was originally derived for contents located within elastic frame buildings, was found to be more efficient than considering total floor accelerations alone but was underconservative by a mean of 17% for yielding multistorey buildings. A design procedure considering content sliding using the parametric equation and an example are provided. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Evaluating the impact of climate change in threshold values of thermodynamic indices during pre-monsoon thunderstorm season over Eastern India     

Sahu  Rajesh Kumar  Dadich  Jiteshwar  Tyagi  Bhishma  Vissa  Naresh Krishna  Singh  Jyotsna 《Natural Hazards》2020,102(3):1541-1569

Natural Hazards - The present study analyses thermodynamic indices variation over three sites of eastern Indian region: Bhubaneswar, Kolkata and Ranchi, associated with pre-monsoon thunderstorms...  相似文献   

Prediction of spatially distributed seismic demands in specific structures: Ground motion and structural response     

Brendon A. Bradley  Rajesh P. Dhakal  Gregory A. MacRae  Misko Cubrinovski 《地震工程与结构动力学》2010,39(5):501-520

The efficacy of various ground motion intensity measures (IMs) in the prediction of spatially distributed seismic demands (engineering demand parameters, (EDPs)) within a structure is investigated. This has direct implications to building‐specific seismic loss estimation, where the seismic demand on different components is dependent on the location of the component in the structure. Several common IMs are investigated in terms of their ability to predict the spatially distributed demands in a 10‐storey office building, which is measured in terms of maximum interstorey drift ratios and maximum floor accelerations. It is found that the ability of an IM to efficiently predict a specific EDP depends on the similarity between the frequency range of the ground motion that controls the IM and that of the EDP. An IMs predictability has a direct effect on the median response demands for ground motions scaled to a specified probability of exceedance from a ground motion hazard curve. All of the IMs investigated were found to be insufficient with respect to at least one of magnitude, source‐to‐site distance, or epsilon when predicting all peak interstorey drifts and peak floor accelerations in a 10‐storey reinforced concrete frame structure. Careful ground motion selection and/or seismic demand modification is therefore required to predict such a spatially distributed demands without significant bias. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Sonolytic Decolorization of Textile Wastewater Containing a Mixture of Reactive,Acid and Disperse Dyes          下载免费PDF全文

Akshaya Kumar Verma  Puspendu Bhunia  Rajesh Roshan Dash  Rajeshwar Dayal Tyagi  Rao Y Surampalli  Tian C Zhang 《洁净——土壤、空气、水》2015,43(5):767-774

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A saga of the 1896 South Iceland earthquake sequence: magnitudes,macroseismic effects and damage     

Ragnar Sigbjörnsson  Rajesh Rupakhety 《Bulletin of Earthquake Engineering》2014,12(1):171-184

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