Adsorption of Cadmium Ions from Aqueous Solution Using Granular Activated Carbon and Activated Clay     

Kailas L. Wasewar  Pradeep Kumar  Shri Chand  Bina N. Padmini  Tjoon Tow Teng 《洁净——土壤、空气、水》2010,38(7):649-656

The present study was aimed at removing cadmium ions from aqueous solution through batch studies using adsorbents, such as, granular activated carbon (GAC) and activated clay (A‐clay). GAC was of commercial grade where as the A‐clay was prepared by acid treatment of clay with 1 mol/L of H₂SO₄. Bulk densities of A‐clay and GAC were 1132 and 599 kg/m³, respectively. The surface areas were 358 m²/g for GAC and 90 m²/g for A‐clay. The adsorption studies were carried out to optimize the process parameters, such as, pH, adsorbent dosage, and contact time. The results obtained were analyzed for kinetics and adsorption isotherm studies. The pH value was optimized at pH 6 giving maximum Cd removal of 84 and 75.2% with GAC and A‐clay, respectively. The adsorbent dosage was optimized and was found to be 5 g/L for GAC and 10 g/L for A‐clay. Batch adsorption studies were carried out with initial adsorbate (Cd) concentration of 100 mg/L and adsorbent dosage of 10 g/L at pH 6. The optimum contact time was found to be 5 h for both the adsorbents. Kinetic studies showed Cd removal a pseudo second order process. The isotherm studies revealed Langmuir isotherm to better fit the data than Freundlich isotherm.  相似文献   

Seismic Source Parameters of Normal-Faulting Inslab Earthquakes in Central Mexico     

Quetzalcoatl Rodríguez-Pérez  Shri Krishna Singh 《Pure and Applied Geophysics》2016,173(8):2587-2619

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Dynamic rupture and stress change in a normal faulting earthquake in the subducting Cocos plate     

Takeshi Mikumo  Miguel A. Santoyo  & Shri Krishna Singh 《Geophysical Journal International》2000,140(3):611-620

A large nearly vertical, normal faulting earthquake ( M _w = 7.1) took place in 1997 in the Cocos plate, just beneath the ruptured fault zone of the great 1985 Michoacan thrust event ( M _w = 8.1). Dynamic rupture and resultant stress change during the 1997 earthquake have been investigated on the basis of near-source strong-motion records together with a 3-D dynamic model.
Dynamically consistent waveform inversion reveals a highly heterogeneous distribution of stress drop, including patch-like asperities and negative stress-drop zones. Zones of high stress drop are mainly confined to the deeper, southeastern section of the vertical fault, where the maximum dynamic stress drop reaches 280 bars (28 MPa). The dynamically generated source time function varies with location on the fault, and yields a short slip duration, which is caused by a short scalelength of stress-drop heterogeneities. The synthetic seismograms calculated from the dynamic model are generally consistent with the strong-motion velocity records in the frequency range lower than 0.5 Hz.
The pattern of stress-drop distribution appears, in some sense, to be consistent with that of coseismic changes in shear stress resulting from the 1985 thrust event. This consistency suggests that the stress transfer from the 1985 event to the subducting plate could be one of the possible mechanisms that increased the chance of the occurrence of the 1997 earthquake.  相似文献   

Simple rules for choosing fault planes in almost real-time post-earthquake loss assessments     

Salgado-Gálvez  Mario A.  Ordaz  Mario  Huerta  Benjamín  Singh  Shri K.  Pérez-Campos  Xyoli 《Natural Hazards》2020,103(1):639-657

Natural Hazards - Rainfall-triggered landslides are the most common type of mass movement seen along the tropical belt due to the prevalence of monsoons. These landslides can be forecasted by...  相似文献   

Factors responsible for driving the glaciation in the Sarchu Plain,eastern Zanskar Himalaya,during the late Quaternary          下载免费PDF全文

Shubhra Sharma  Pritam Chand  Pinky Bisht  Anil D. Shukla  S. K. Bartarya  Y. P. Sundriyal  Navin Juyal 《第四纪科学杂志》2016,31(5):495-511

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Characterization of aerosol optical depth, aerosol mass concentration, UV irradiance and black carbon aerosols over Indo-Gangetic plains, India, during fog period     

K. V. S. Badarinath  Shailesh Kumar Kharol  T. R. Kiran Chand  K. Madhavi Latha 《Meteorology and Atmospheric Physics》2011,111(1-2):65-73

Every year during winter months (December?CJanuary) fog formation over Indo-Gangetic plains (IGP) of Indian region is believed to create numerous hazards. The present study addresses variations in aerosol optical properties, aerosol mass concentration and their impact on solar irradiance for pre-during-post fog conditions of December 2004 over IGP, India. Continuous measurements on aerosol optical depth (AOD), total aerosol mass concentration, black carbon (BC) aerosols, UV_ery and UVA were carried out for pre, during and post fog periods over study site of Allahabad, India, during December 2004 as a part of Aerosol Land Campaign-II conducted by Indian Space Research Organization (ISRO). High aerosol mass concentrations were observed during fog and post-fog periods. Accumulation mode particle loading was found to be high during pre-fog period and coarse mode particle loading was observed to be high during fog and post-fog periods. Considerable reduction in UV_ery and UVA irradiance was observed during fog period compared with pre and post-fog periods. Analysis of NOAA-HYSPLIT model runs suggested that enhanced biomass burning episodes down-wind to the study area increased the concentration of AOD and BC.  相似文献   

Slope stability analysis using artificial intelligence techniques     

Shakti Suman  S. Z. Khan  S. K. Das  S. K. Chand 《Natural Hazards》2016,80(2):727-739

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Evaluation and modelling of Tertiary source rocks in the central Arctic Ocean     

Ute Mann  Jochen Knies  Shyam Chand  Wilfried Jokat  Ruediger Stein  Janine Zweigel   《Marine and Petroleum Geology》2009,26(8):1624-1639

With the recently recovered organic-rich sediments of early Tertiary age from the Lomonosov Ridge by the Integrated Ocean Drilling Program (IODP) Expedition 302, the first data collection directly from source rocks of the central basins of the Arctic Ocean is now available. Using the results of seismic interpretations and published sedimentological and organic geochemical data from Expedition 302, the framework for the first quantitative assessment of source-rock quality and distribution of the Palaeogene sediments was modelled in the central Arctic Ocean. The modelling results suggest that an approximately 100-m-thick Early to Middle Eocene sedimentary sequence of good to very good source rocks exists along a 75 km long transect across the Lomonosov Ridge. In-situ generation of hydrocarbons is unlikely because the overburden (200–250 m) and consequently the thermal maturity are too low. Burial history and thermal modelling reveal that an additional overburden of at least 1000 m is necessary to start hydrocarbon generation along the ridge. However, source-rock modelling results show that good source-rock potential may exist in correlative units in the adjacent Amundsen Basin. Simulated organic carbon contents of 1.5–5%, coupled with an overburden of 1000–1200 m, and heat flow anomalies (117 and 100 mW m⁻²) due to the vicinity to the Gakkel Ridge spreading centre indicate that necessary conditions for hydrocarbon expulsion are already reached, and point to viability of a potential petroleum system. Our results support the hypothesis that deposition of a potentially good hydrocarbon source rock occurred across the entire Arctic Basin and adjacent margins during the early Tertiary.  相似文献   

Forest fires monitoring using envisat-aatsr data     

K. V. S. Badarinath  K. Madhavi Latha  T. R. Kiran Chand 《Journal of the Indian Society of Remote Sensing》2004,32(4):317-322

Forests over Indian region are fire prone during summer season and effective means for monitoring such events is important. Satellite data with its repetitive and wide area coverage provides data sets required for monitoring such events. The advances in sensor technology and multi-satellite systems have improved capability for monitoring such events. The present study addresses forest fires monitoring using night time data sets of ENVISAT-AATSR data over Indian Region. The results of the study indicated that region specific algorithms are required for forest fire detection as soils in tropical regions have higher temperatures during night time.  相似文献   

LOCAL SCOUR AROUND BRIDGE ABUTMENTS   总被引：2，自引：0，他引：2  

Er. Shri Ram CHAURASIA  Pande B.B. LAL Assistant Professor  Civil Engineering Department  Madan Mohan Malaviya Engineering College  Gorakhpur- 《国际泥沙研究》2002,17(1)

1 INTRODUCTION The protrusion of a bridge abutment or a spur dike into the main channel creates a disturbance and obstruction to the otherwise equilibrium state of sediment transportation in an alluvial river. The flow accelerates and separates at the upstream face of the abutment as it moves past the obstacle, creating a vortex trail that moves downstream in a direction approximately perpendicular to the structure. The result is that the bed around the structure is eroded locally. The l…  相似文献