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Bioavailability of Arsenic and Antimony in Terrestrial Ecosystems:A Review

Pedosphere 2019年第6期29卷 681-720页

作者： Saeed BAGHERIFAM Trevor CBROWN Christopher MFELLOWS ravi NAIDU Chemistry-School of Science and Technology University of New EnglandArmidale NSW 2351(Australia Global Centre for Environmental Remediation Faculty of Science and Inform ation TechnologyUniversity o f NewcastleUniversity DriveCallaghan N S W 2308(Australia

Arsenic (As) and antimony (Sb) are metalloids that belong to group 15 of the periodic table and exhibit toxic properties in the environment. They mostly occur naturally at low concentrations in soil, although these can be significantly elevated in both aquatic and terrestrial food chains as a result of dispersion from anthropogenic sources, e.g ., mining activities. The bioavailability, i.e., the proportion of the contaminant in soil and dust that is available for uptake by plants and other living organisms, presents the greatest risk to terrestrial ecosystems. Various in vivo and in vitro methods have been used to measure As and Sb bioaccessibility in soil and dust. In vivo measurement of bioavailability can be time consuming, expensive, and unethical;thus, in vitro methods are commonly preferred. However, there is considerable uncertainty around the efficacy of in vitro tools used to measure the bioavailable fractions of As and Sb. The results of these methods are dependent on many variables, e.g., soil characteristics, contaminant sources, and chemical composition of in vitro methods. Therefore, substantial variations are observed between in vitro and in vivo results obtained from different test animals and endpoints. In this paper, we review the literature on As and Sb bioavailability in terrestrial ecosystems and current in vivo and in vitro techniques used for assessing bioavailability and bioaccessibility of metalloids. This would reveal research gaps and allow scientists and environmental policy makers to gain a deeper understanding of the potential risks associated with these metalloids in the environment.

关键词： Bioaccessibility Bioavailable fraction Contamination Environmental risk assessment Metalloids Phytoavailability Relative bioavailability Soil characteristics Toxicant

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CO_(2)Emissions Post-COP26:Who is Responsible to Curb the Flow?Does it Matter if We Can Make it a Win-Win?

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Energy & Environmental Materials 2022年第3期5卷 683-685页

作者： James Crawshaw S.ravi P.Silva Advanced Technology Institute University of SurreyGuildfordUK

The debate about climate change is highly *** everyone is convinced that CO_(2)emissions are worth curbing despite seemingly irrefutable evidence in the IPCC’s latest report.[1]Some have vested interests in exploiting fossil fuels while others think alternative,cheaper solutions can be *** that have shifted from manufacturing to service-based economies will find it easier to *** countries with relatively low carbon emissions per capita but large populations believe it is unfair that they should have to bear heavy costs of decarbonization to solve a problem that wealthier countries have created.

关键词： Who is Responsible to Curb the Flow CO_(2)Emissions Post-COP26 Does it Matter if We Can Make it a Win-Win

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A review of electrokinetically enhanced bioremediation technologies for PHs

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Journal of Environmental Sciences 2020年第2期32卷 31-45页

作者： Anish Saini Dawit Nega Bekele Sreenivasulu Chadalavada Cheng Fang ravi Naidu Global Centre for Environmental Remediation University of NewcastleCallaghanNewcastle 2308NSWAustralia Cooperative Research Centre for Contamination Assessment and Remediation of the Environment(CRC CARE) University of NewcastleCallaghanNewcastle 2308NSWAustralia

Since the early 1980’s there have been several different strategies designed and applied to the remediation of subsurface environment including physical, chemical and biological *** have had varying degrees of success in remediating contaminants from subsurface soils and *** objective of this review is to examine the range of technologies for the remediation of contaminants, particularly petroleum hydrocarbons, in subsurfaces with a specific focus on bioremediation and electrokinetic ***, this review examines the efficiency of remediation carried out by combining bioremediation and electrokinetic ***, which are slowly becoming the selected chemicals for mobilizing contaminants, are also considered in this *** current knowledge gaps of these technologies and techniques identified which could lead to development of more efficient ways of utilizing these technologies or development of a completely new technology.

关键词： Subsurface contamination Remediation Petroleum hydrocarbons (PH) Electrokinetics Bioremediation

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Experimental,analytical and numerical studies on concrete encased trapezoidally web profiled cold-formed steel beams by varying depth-thickness ratio

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Frontiers of Structural and Civil Engineering 2020年第4期14卷 930-946页

作者： Divahar ravi Aravind Raj PONSUBBIAH Sangeetha Sreekuniar PRABHA Joanna Philip SARATHA Department of Civil Engineering Aarupadai Veedu Institute of TechnologyChennai 603104India Department of Civil Engineering Hindustan Institute of Technology and ScienceChennai 603103India

Concrete encased with trapezoidally corrugated web profiled cold-formed steel beams are used worldwide to improve resistance toward fire and corrosion,higher load carrying capacity as well as significant increase in the bending stiffness by encasing concrete on the beam *** present work gives a detailed description on the experimental,analytical and numerical investigation on the flexural behavior of concrete encased trapezoidally corrugated web profiled cold-formed steel beams which were simply supported at both ends and subjected to two point symmetric *** flexural behavior of such structure has been experimentally tested to failure under pure *** find the effct of concrete encasement in the web,12 experiments were conducted by two different *** having three different web corrugation angles of 0°,30°,and 45°with two different web depth-thickness(dw/tw)ratios of 60 and 80 were *** results such as load-deflection relationship,ultimate capacity,load-strain relationship,moment-curvature curves,ductility and failure mode indices of the specimens are *** the static bending tests the concrete encased trapezoidally corugated web beam showed improved moment carrying capacity,ductility bchavior and the resistance to transverse deflections in comparison to concrete encased with plain web *** for the beams with concrete encased 30°trapezoidally corrugated web having(dw/tw)ratio 60 and 80,the loading capacity was improved about 54%and 67.3%and the ductility also increased about l.6 and 3.6 times,when compared to concrete encased beams with plain *** research should contribute to the future engineering applications on seismic resistant structures and efficient usage of concrete encased with cold-formed steel beams by exhibiting its super elasto-plastic *** analytical and numerical results showed good agreement with the experimental results at yield load,which indicates that the proposed analyti

关键词： concrete encased beam trapezoidally corrugated web loading capacity super elasto-plastic

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Opportunistic Routing with Multi-Channel Cooperative Neighbour Discovery

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Intelligent Automation & Soft Computing 2023年第2期35卷 2367-2382页

作者： S.Sathish Kumar G.ravi AVS College of Technology Salem636106India Sona College of Technology Salem636005India

Due to the scattered nature of the network,data transmission in a dis-tributed Mobile Ad-hoc Network(MANET)consumes more energy resources(ER)than in a centralized network,resulting in a shorter network lifespan(NL).As a result,we build an Enhanced Opportunistic Routing(EORP)protocol architecture in order to address the issues raised *** proposed routing protocol goal is to manage the routing cost by employing power,load,and delay to manage the routing energy consumption based on theﬂooding of control pack-ets from the target *** to the goal of the proposed protocol techni-que,it is possible to manage the routing cost by applying power,load,and *** proposed technique also manage the routing energy consumption based on theﬂooding of control packets from the destination node in order to reduce the routing *** packet exchange between the target and all the nodes,on the other hand,is capable of having an inﬂuence on the overall efﬁciency of the *** EORP protocol and the Multi-channel Cooperative Neighbour Discovery(MCCND)protocol have been designed to detect the cooperative adja-cent nodes for each node in the routing route as part of the routing path discovery process,which occurs during control packet *** control packet transmission is taking place during the routing path discovery process,the EORP protocol and the Multi-channel Cooperative Neighbour Discovery(MCCND)protocol have been designed to detect the cooperative adjacent nodes for each node in the *** included is a simulation of these protocols in order to evaluate their performance across a wide range of packet speeds using Constant Bit Rate(CBR).When the packet rate of the CBR is 20 packets per second,the results reveal that the EORP-MCCND is 0.6 s quicker than the state-of-the-art protocols,according to theﬁ*** that the CBR packet rate is 20 packets per second,the EORP-MCCND achieves 0.6 s of End 2 End Delay,0.05 s of Routing Overhea

关键词： Macro-addressable network power-and load-aware routing deterministic and opportunistic routing gradient routing multi-channel cooperative neighbor discovery

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An Upper and Lower Solution Theory for the Problem(G′(y))′+f(t,y)=0 on Finite and Infinite Intervals

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Acta Mathematica Sinica,English Series 2006年第3期22卷 827-832页

作者： ravi P.AGARWAL Donal O'REGAN Svatoslav STANEK Department of Mathematical Sciences Florida Institute of TechnologyMelbourneFlorida 32901-6975USA Department of Mathematics National University of IrelandGalwayIreland Department of Mathematical Analysis Faculty of SciencePalack University

A new upper and lower solution theory is presented for the second order problem （G＇（y））＇＋ f（t, y） = 0 on finite and infinite intervals. The theory on finite intervals is based on a Leray-Schauder alternative,... 详细信息

关键词： alternative upper and lower solutions infinite interval diagonalization process Leray-Schauder alternative

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Risk assessment of heavy metal contaminated soil in the vicinity of a lead/zinc mine

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Journal of Environmental Sciences 2005年第6期17卷 881-885页

作者： LI Jing XIE Zheng-miao ZHU Yong-guan ravi Naidu Institute for Soil and Water Resources and Environment Zhejiang University Hangzhou 310029 China Research Centre for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Centre for Environmental Risk Assessment and Remediation University of South Australia Mawson Lakes SA 5095 Australia

Heavy metal contamination of soils through anthropogenic activities is a widespread and serious problem confronting scientists and regulators throughout the world. In this study we investigated the distribution, chemical species and availability of lead, zinc, cadmium and copper in nine surface（0 to 20 cm） soils from near an abandoned lead/zinc mine tailings located in Shaoxing, Zhejiang, China. Total heavy metal contents ranged from 5271 to 16369 mg/kg for Pb, 387 to 1221 mg/kg for Zn, 3.0 to 9.3 mg/kg for Cd and 65 to 206 mg/kg for Cu. In general, all heavy metals exceeded China National Standards for Soil Environmental Quality of Heavy Metals by a factor of 3-65 times. Comparison of the heavy metal concentrations（Pb, Zn, Cd and Cu） with clay content revealed a strongly significant relationship while significant relationship（ P 〈 0.001 ） was also obtained between Cd ＋ Zn and Pb ＋ Cu. Solid phase speciation of the soils using Tessier procedure showed that the heavy metals were distributed in the order： residual 〉〉 organically complexed-Fe-Mn oxides occluded 〉 carbonate bound 〉 exchangeable 〉 water soluble. In the organic matter fraction, the ratio of Pb（29.1% ） to its total concentration in the soils was higher than those of Zn（4.70% ）, Cd（3.16% ） and Cu（9.50% ）. The percentages of the water soluble and the exchangeable fractions of Pb（1.80% ） and Cd（2.74% ） were markedly greater than those of Zn（0.10% ） and Cu（0.15% ）, suggesting that Pb and Cd are relatively more mobile and hence more toxic in the contaminated soils. Strongly significant relationships between H20-Pb, H20-Zn and H20-Cu, strong positive correlations between H20-Pb, H20-Zn, H20-Cu and organic matter in soil were found. The content of H20-Pb, H20-Zn, H20-Cu was negatively correlated with pH values. The similar negative relationships between pH values and exchangeable heavy metals were also recorded. It is suggested that increasing soil pH or liming the soil could decrease bioavailability of heavy met

关键词： fractionation heavy metal mining tailings risk assessment soil pollution

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Journal of Ocean Engineering and Science 2023年第2期8卷 111-123页

作者： Raj Kumar ravi Shankar Verma Atul Kumar Tiwari Department of Mathematics Faculty of Engineering&TechnologyVeer Bahadur Singh Purvanchal UniversityJaunpur222003India Department of Mathematics Motihari College of EngineeringMotihari845401BiharIndia

This work is devoted to get a new family of analytical solutions of the(2+1)-coupled dispersive long wave equations propagating in an infinitely long channel with constant depth,and can be observed in an open sea or in wide *** solutions are obtained by using the invariance property of the similarity transformations method via one-parameter Lie group *** repeated use of the similarity transformations method can transform the system of PDEs into system of *** adequate restrictions,the reduced system of ODEs is *** simulation is performed to describe the solutions in a physically meaningful *** profiles of the solutions are simulated by taking an appropriate choice of functions and constants involved *** each animation,a frame for dominated behavior is *** exhibit elastic multisolitons,single soliton,doubly solitons,stationary,kink and parabolic *** results are significant since these have confirmed some of the established results of *** et al.(2020)and *** et al.(2020).Some of their solutions can be deduced from the results derived in this *** results in the existing literature are different from those in this work.

关键词： Dispersive long wave equations Solitons Invariants Lie-group Similarity solutions

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In-situ probing of thermal desorption of vapor molecules on a nanowire via work function variance

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Nano Research 2016年第11期9卷 3334-3345页

作者： Kovur Prashanthi John Eric Hawk Ryan McGee ravi Gaikwad Thomas Thundat Ingenuity Lab Department of Chemical and Materials Engineering University of Alberta Edmonton AB T6G 2V4 Canada

Nanowire sensors based on variations of their electrical properties show great potential for real-time, in situ monitoring of molecular adsorption and desorption. Although the molecular adsorption-induced change in the electronic work function is very sensitive, it does not have any specificity. However, the temperature dependency of the adsorption-induced work function variation can provide limited selectivity based on the desorption temperature. In this study, we report the in situ probing of molecular desorption by monitoring the work function variations of a single Pt nanowire as a function of temperature. The work function of a clean Pt nanowire shows a significant variation due to vapor adsorption at room temperature. Increasing the temperature of the nanowire results in a variation of the work function due to molecular desorption. Experimentally measured differential work function as a function of temperature shows desorption peaks at 36 and 44 ℃ for methanol and ethanol molecules respectively. Adsorption-induced variation of the Pt nanowire work function was further confirmed using ultraviolet photoelectron spectroscopy before and after exposure to methanol vapor. These results show that the molecular adsorption/desorption-induced variation of the work function and its temperature dependency can be used for developing nanoscale electro-calorimetric sensors.

关键词： Kelvin probe microscopy nanowires thermal desorption work function

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EXISTENCE AND UNIQUENESS OF NON-TRIVIAL SOLUTION OF PARABOLIC p-LAPLACIAN-LIKE DIFFERENTIAL EQUATION WITH MIXED BOUNDARIES

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Acta Mathematica Scientia 2016年第6期36卷 1780-1792页

作者：魏利陈蕊 ravi P.AGARWAL Patricia YJ WONG School of Mathematics and Statistics Hebei University of Economics and Business Department of Mathematics Texas A&M University-Kingsville Department of Mathematics Faculty of ScienceKing Abdulaziz University School of Electrical and Electronic Engineering Nanyang Technological University

One parabolic p-Laplacian-like differential equation with mixed boundaries is au/at in the corresponding studies is replaced by a（au/at）, studied in this paper, where the item au/at which makes it more general. The sufficient condition of the existence and uniqueness of non-trivial solution in L2（O, T; L2 （Ω）） is presented by employing the techniques of splitting the boundary problems into operator equation. Compared to the corresponding work, the restrictions imposed on the equation are weaken and the proof technique is simplified. It can be regarded as the extension and complement of the previous work.

关键词： maximal monotone operator Caratheodory'conditions subdifferential p-Laplacian-tike equation nontrivial solution

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