检索结果-南通市图书馆

Adsorption characteristics of humic acid-immobilized amine modified polyacrylamide/bentonite composite for cationic dyes in aqueous solutions

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2009年第7期21卷 884-891页

作者： t. s. Anirudhan P. s. suchithra Department of Chemistry University of Kerala Kariavattom Trivandrum-695 581 India.

Humic acid-immobilized amine modified polyacrylamide/bentonite composite （HA-Am-PAA-B） was prepared and used as an adsorbent for the adsorption of cationic dyes （Malachite Green （MG）, Methylene Blue （MB） and Crystal Violet （CV）） from aqueous solutions. the polyacrylamide/bentonite composite （PAA-B） was prepared by intercalative polymerization of acrylamide with Nabentonite in the presence of N,N＇-methylenebisacrylamide as a crosslinking agent and hexamethylenediammine as propagater. PAA-B was subsequently treated with ethylenediammine to increase its loading capacity for HA. the surface characterizations of the adsorbent were investigated. the adsorbent behaved like a cation exchanger and more than 99.0% removal of dyes was detected at pH range 6.0-8.0. the capacity of HA-Am-PAA-B was found to decrease in the following order： MG〉MB〉CV. the kinetic and isotherm data were interpreted by pseudo-second order rate equation and Freundlich isotherm model, respectively. Experiments were carried out using binary solute systems to assess the competitive adsorption phenomenon. the experimental isotherm data for each binary solute combination of MG, MB and CV were analyzed using sheindrof-Rebhun-sheintuch （sRs）（multicomponent Freundlich type） equation.

关键词： humic acid polymer/clay composite dye adsorption isotherm regeneration

Evaluation of red soil-bentonite mixtures for compacted clay liners

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 697-710页

作者： A.s.Devapriya t.thyagaraj Department of Civil Engineering Indian Institute of Technology MadrasChennai600036India

Compacted clay liners are an integral part of the waste landfills,which are provided to contain the leachate within the landfills and protect the surrounding ***,locally available natural soils are used for the construction of compacted clay liners if they satisfy the design ***,not all soils in their natural state satisfy all the design criteria for the liner ***,there is a definite need to modify the locally available natural soils by blending with bentonite to meet the required design criteria for the *** view of this,the present study evaluates the suitability of an Indian red soil enhanced with bentonite as a liner *** achieve this,a series of experiments were carried out using locally available red soil and ***,the suitability of the red soil was evaluated as a liner *** experimental results showed that the red soil met all the selection criteria stipulated by the Environmental Protection Agencies(EPAs)for the liners except the hydraulic conductivity ***,the red soil was mixed with bentonite contents of 10%,20%and 30%,and the red soil-bentonite mixtures were evaluated for their suitability for liners in their compacted ***,as the liners in the arid and semi-arid regions are subjected to moisture variations due to seasonal moisture fluctuations and other factors,the red soil-bentonite mixtures were subjected to wetdry cycles,and their suitability was evaluated after wet-dry *** experimental results revealed that all the red soil-bentonite mixtures met the stipulated EPA criteria for the liners in the as-compacted ***,the red soil-bentonite mixtures with 20%and 30%bentonite contents only satisfied the hydraulic conductivity requirement even after wet-dry *** experimental findings were supplemented with the microstructural insights captured through digital camera images,scanning electron microscopy(sEM),and mercury intrusion porosimetry(M

关键词： Compacted clay lines Hydraulic conductivity Wet-dry cycles Microstructure

Flow of Oldroyd-B fluid with nanoparticles and thermal radiation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2015年第1期36卷 69-80页

作者： t.HAYAt t.HUssAIN s.A.sHEHZAD A.ALsAEDI Department of Mathematics Quaid-i-Azam University Nonlinear Analysis and Applied Mathematics (NAAM) Research Group Faculty of ScienceKing Abdulaziz University Department of Mathematics Faculty of Computing Mohammad Ali Jinnah University Department of Mathematics COMSATS Institute of Information Technology

the two-dimensional boundary layer flow of an Oldroyd-B fluid in the presence of nanoparticles is investigated. Convective heat and mass conditions are considered in the presence of thermal radiation and heat generation. the Brownian motion and thermophoresis effects are retained. the nonlinear partial differential equations are reduced into the ordinary differential equation （ODE） systems. the resulting ODE systems are solved for the series solutions. the results are analyzed for various physical parameters of interest. Numerical values of the local Nusselt and sherwood numbers are also computed and analyzed.

关键词： nanoparticle Oldroyd-B fluid heat generation convective condition

Analysis of long-term dependence phenomenon in Benue River flow process and its hypothesis testing

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Oceanology and Limnology 2008年第3期26卷 313-322页

作者： martins Y. OtACHE 李致家 Mohammad BAKIR state Key Laboratory of Hydrology-Water Resources ＆ Hydraulic Engineering Hohai University Nanjing 210098 China

In this paper, the long-term dependence phenomenon （the Hurst Effect） which characterizes hydrological and other geophysical times series is studied. the long-term memory is analysed for both daily and monthly streamflow series of the Benue River at Makurdi, Nigeria by using heuristic methods and testing specifically the null hypothesis of short-term memory in the monthly flow series. Results obtained by applying heuristic procedures indicated that there may be the presence of long-term memory component in mean daily flow series but there is no discernible reason to suspect the presence in both average monthly and maximum monthly flow series （extreme event）. Hypothesis testing was conducted by using original and modified versions of rescaled range statistic. When the modified rescaled range, which accounts for short-term memory in the series, is used, the null hypothesis is accepted for both the average monthly and maximum monthly flow series, indicating little or no probable presence of long-term memory in the series. An identical conclusion is also arrived at when second null hypothesis for independence of the monthly flow series is tested. therefore, apart from the mean daily flow series, there is little evidence of long-term dependence in the Benue River streamflow series at Makurdi. However, considering the limited length of data used, the results are inconclusive.

关键词： Hurst exponent hydrological method time series river flow long memory Nigeria

Numerical analysis of thermal plasma scrubber for CF4 decomposition

在线全文

学校读者我要写书评

暂无评论

Plasma science and technology 2019年第6期21卷 9-14页

作者： J KO t H KIM s CHOI Department of Nuclear and Energy Engineering Jeju National University Jeju 63243 Republic of Korea Institute for Nuclear science and technology Jeju National University Jeju 63243 Republic of Korea

CF4 gas emitted in the semiconductor and display manufacturing process is a very harmful greenhouse *** must be removed or converted safely due to its extreme *** a CF4 decomposition system using a thermal plasma scrubber was commercialized,its removal efficiency is *** this work,a numerical analysis of CF4 decomposition in the thermal plasma scrubber was carried out in order to propose an efficient decomposition *** decomposition and recombination temperatures of CF4 were analyzed using thermodynamic equilibrium *** chemical reaction of CF4 decomposition into carbon and fluorine gas was considered in this numerical *** injection position and angle of the CF4 were controlled in order to enhance the decomposition *** vertical injection of CF4 near the torch exit improved the mixing of the CF4 with the thermal plasma *** addition,it was confirmed that the high temperature region expanded due to a vortex generated by strong turbulence in the bottleneck-shaped *** a result,it is revealed that the CF4 injection location and the reactor configuration are the most important factors in improving the decomposition rate.

关键词： numerical simulation decomposition CF4 thermal plasma scrubber

traction power substation balance and losses estimation in AC railways using a power transfer device through Monte Carlo analysis

在线全文

学校读者我要写书评

暂无评论

Railway Engineering science 2022年第1期30卷 71-95页

作者： Vitor A.Morais Antonio P.martins Department of Electrical and Computer Engineering Faculty of EngineeringUniversity of PortoPorto 4200465Portugal

the high dynamic power requirements present in modern railway transportation systems raise research challenges for an optimal operation of railway electrification. this paper presents a Monte Carlo analysis on the application of a power transfer device installed in the neutral zone and exchanging active power between two sections. the main analyzed parameters are the active power balance in the two neighbor traction power substations and the system power losses. A simulation framework is presented to comprise the desired analysis and a universe of randomly distributed scenarios are tested to evaluate the effectiveness of the power transfer device system. the results show that the density of trains and the relative branch length of a traction power substation should be considered in the evaluation phase of the best place to install a power transfer device, towards the reduction of the operational power losses, while maintaining the two substations balanced in terms of active power.

关键词： Electric traction systems Monte Carlo analysis Power transfer device Power quality Railway power systems smart railways

Finite element models to represent seismic activity of the Indian plate

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2017年第1期8卷 81-91页

作者： s.Jayalakshmi s.t.G.Raghukanth Department of Civil Engineering Indian Institute of TechnologyMadras 600036India

Quantification of seismic activity is one of the most challenging problems faced by earthquake engineers in probabilistic seismic hazard analysis. Currently, this problem has been attempted using empirical approaches which are based on the regional earthquake recurrence relations from the available earth- quake catalogue. However, at a specified site of engineering interest, these empirical models are asso- ciated with large number of uncertainties due to lack of sufficient data. Due to these uncertainties, engineers need to develop mechanistic models to quantify seismic activity. A wide range of techniques for modeling continental plates provides useful insights on the mechanics of plates and their seismic activity. Among the different continental plates, the Indian plate experiences diffused seismicity. In India, although Himalaya is regarded as a plate boundary and active region, the seismicity database indicates that there are other regions in the Indian shield reporting sporadic seismic activity. It is expected that mechanistic models of Indian plate, based on finite element method, simulate stress fields that quantify the seismic potential of active regions in India, this article explores the development of a finite element model for Indian plate by observing the simulated stress field for various boundary conditions, geological and theological conditions. the study observes that the magnitude and direction of stresses in the plate is sensitive to these conditions, the numerical analysis of the models shows that the simulated stress field represents the active seismic zones in India.

关键词： Indian platePlate driving forcesFinite element modeseismicityCratons

timoshenko inclusions in elastic bodies crossing an external boundary at zero angle

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica solida sinica 2017年第3期30卷 327-333页

作者： A.M. Khludnev t.s. Popova Lavrentyev Institute of Hydrodynamics of R_As Novosibirsk State University Novosibirsk 630090 Russia North-Eastern Federal University Yakutsk 677000 Russia

the paper concerns an analysis of equilibrium problems for 2D elastic bodies with a thin timoshenko inclusion crossing an external boundary at zero angle. the inclusion is assumed to be delaminated, thus forming a crack between the inclusion and the body. We consider elastic inclusions as well as rigid inclusions. to prevent a mutual penetration between the crack faces, inequality type boundary conditions are imposed at the crack faces. theorems of existence and uniqueness are established. Passages to limits are investigated as a rigidity parameter of the elastic inclusion going to infinity.

关键词： thin timoshenko inclusion Crack Delamination Fictitious domain method Non-penetration

Chalcopyrite solar cells——state-of-the-art and options for improvement

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2023年第1期66卷 3-17页

作者： s.siebentritt t.P.Weiss Laboratory for Photovoltaics Department of Physics and Materials ScienceUniversity of LuxembourgBelvaux 4422Luxembourg

Chalcopyrite solar cells will have to play an important role to mitigate the climate crisis,because of their particularly low carbon *** in these semiconductors is due to native defects and intentional alkali *** recent progress in efficiency has been made possible by post-deposition treatments with heavy *** states and band gap distribution are the main limitations for the open circuit voltage in state-of-the-art chalcopyrite solar *** efficiency limitations are due to the increased diode factor because of metastable defect *** with Ag opens new possibilities of band-edge engineering,as well as seems to improve the diode *** state-of-the-art cells the back contact is passivated by a Ga gradient;considerable research has been done to passivate the back contact by structured or continuous dielectric layers.A leap forward in efficiency can be expected from tandem *** solar cells show promising potential as bottom cells as well as top cells.

关键词： doping tail states alkali treatment efficiency