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Coconut coir pith, a lignocellulosic polymer, is an unwanted by‐product of the coir fiber industry. The pith was used as a biosorbent for the removal of Molybdenum(VI) after modification with a cationic surfactant, hexadecyltrimethylammonium bromide. The optimum pH for maximum adsorption of Mo(VI) was found to be 3.0. Langmuir, Freundlich and Dubinin Radushkevich isotherms were used to model the adsorption equilibrium data and the system was seen to follow all three isotherms. The Langmuir adsorption capacity of the biosorbent was found to be 57.5 mg g–1. Kinetic studies showed that the adsorption generally obeyed a second‐order kinetic model. Desorption studies showed that the recovery of Mo(VI) from the spent adsorbent was feasible. The effect of foreign anions on the adsorption of Mo(VI) was also examined. 相似文献
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Sathish Raam Ravichandran Chitra Devi Venkatachalam Mothil Sengottian Sarath Sekar Bhavya Shri Subramaniam Ramasamy Sakthivel Elangovan Siddharth Thorali Sivakumar Shanmuga Sundaram Subramanian 《洁净——土壤、空气、水》2023,51(3):2100305
In the present study, nanocomposite polymeric membranes are fabricated using polyvinyl alcohol (PVA), cellulose acetate (CA) as polymers, and dimethyl sulfoxide (DMSO) as the solvent. To enhance the performance of the membrane, nanoparticles like TiO2, CaO, CdO, and ZrO are added to the polymeric solution and the doped polymeric solution is cast on a glass plate. Nine combinations of membranes are fabricated with two different concentrations (0.1% and 0.2%) of nanoparticles. The basic properties of the membranes such as density, porosity, viscosity, permeability, pure water flux, and water content are studied for the samples. Membrane pore structure and surface properties are identified and it is found that doping nanoparticles on the surface of membranes improve mechanical strength, stability, pore size, etc., allowing the membranes to perform better in extreme industrial-level effluent treatment applications. High-resolution scanning electron microscopy (SEM) shows the homogeneous dispersion of ZrO, TiO2, CaO, and CdO nanoparticles on the surface of the PVA-CA membrane. The doping of nanoparticles on the PVA-CA membrane results in improved mechanical strength and good chemical oxidation stability. In comparison, the PCD-TiO2 sample shows high thermal stability and oxidation stability at high temperatures until 200°C, which has a high potential for treating industrial effluents. 相似文献
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This paper mainly projects the attempts made in analysing the computer line printer outputs of bands 4,5 and 7 obtained from Landsat digital data, with reference to a selected area of Chandrapur project in Chandrapur district, Maharashtra. The distinction into various landuse patterns has been carried out on the printed outputs and they have been compared with the available toposheets ane aerial photos. 相似文献
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Bao K. S. Mohan B. K. Venkatachalam P. Karale R. L. Narula K. K. 《Journal of the Indian Society of Remote Sensing》1986,14(2):9-22
Journal of the Indian Society of Remote Sensing - Around 100 temporal brightness temperature (TB) signatures at 19.35, 22.235 and 31.4 GHz pertaining to broad regions of Land, Sea and Snow/Ice have... 相似文献
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Sangita Zope-Chaudhari Parvatham Venkatachalam Krishna Mohan Buddhiraju 《地球空间信息科学学报》2013,16(2-3):124-133
With the rapid growth of the Internet, the copyright protection problem occurs frequently, and unauthorized copying and distributing of geospatial data threaten the investments of data producers. Digital watermarking is a possible solution to solve this issue. However, watermarking causes modifications in the original data resulting in distortion and affects accuracy, which is very important to geospatial vector data. This article provides distortion assessment of watermarked geospatial data using wavelet-based invisible watermarking. Eight wavelets at different wavelet decomposition levels are used for accuracy evaluation with the help of error measures such as maximum error and mean square error. Normalized correlation is used as a similarity index between original and extracted watermark. It is observed that the increase in the strength of embedding increases visual degradation. Haar wavelet outperforms the other wavelets, and the third wavelet decomposition level is proved to be optimal level for watermarking. 相似文献
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Decisions under uncertainty: a computational framework for quantification of policies addressing infectious disease epidemics 总被引：1，自引：0，他引：1
Armin R. Mikler Sangeeta Venkatachalam Suhasini Ramisetty-Mikler 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(5):533-543
Emerging infectious diseases continue to place a strain on the welfare of the population by decreasing the population’s general
health and increasing the burden on public health infrastructure. This paper addresses these issues through the development
of a computational framework for modeling and simulating infectious disease outbreaks in a specific geographic region facilitating
the quantification of public health policy decisions. Effectively modeling and simulating past epidemics to project current
or future disease outbreaks will lead to improved control and intervention policies and disaster preparedness. In this paper,
we introduce a computational framework that brings together spatio–temporal geography and population demographics with specific
disease pathology in a novel simulation paradigm termed, global stochastic field simulation (GSFS). The primary aim of this
simulation paradigm is to facilitate intelligent what-if-analysis in the event of health crisis, such as an influenza pandemic.
The dynamics of any epidemic are intrinsically related to a region’s spatio–temporal characteristics and demographic composition
and as such, must be considered when developing infectious disease control and intervention strategies. Similarly, comparison
of past and current epidemics must include demographic changes into any effective public health policy for control and intervention
strategies. GSFS is a hybrid approach to modeling, implicitly combining agent-based modeling with the cellular automata paradigm.
Specifically, GSFS is a computational framework that will facilitate the effective identification of risk groups in the population
and determine adequate points of control, leading to more effective surveillance and control of infectious diseases epidemics.
The analysis of past disease outbreaks in a given population and the projection of current or future epidemics constitutes
a significant challenge to Public Health. The corresponding design of computational models and the simulation that facilitates
epidemiologists’ understanding of the manifestation of diseases represents a challenge to computer and mathematical sciences. 相似文献
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Rajinder Bhasin Eystein Grimstad Jan Otto Larsen Ashok K. Dhawan Rajbal Singh S. K. Verma K. Venkatachalam 《Engineering Geology》2002,64(4):351-368
Landslides and other mass movements are serious geo-environmental hazards in the Himalayas. Massive landslides killing tens of thousands of people with catastrophic damages have occurred in the Eastern Himalayan State of Sikkim, which shares common borders with Tibet, Nepal, and Bhutan. This paper describes the investigations carried out on recent landslides in Gangtok, Sikkim, India, with emphasis on the triggering mechanisms that have contributed to the release and creep of natural slopes in the region. It is believed that the intense rainfall in the region not only contributes to rapid erosion and weathering of the rock mass, but also increases the groundwater level that leads to reduction in the stability of natural slopes. A landslide instrumentation programme that includes placement of settlement pillars and piezometers is underway to predict the behaviour of landslides in the area. 相似文献
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