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Groundwater solute chemistry,hydrogeochemical processes and fluoride contamination in phreatic aquifer of Odisha,India

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Geoscience Frontiers 2021年第3期12卷 234-248页

作者： Sudarsan Sahu Utpal Gogoi n.c.nayak central Ground Water Board SERBhujal BhawanBhubaneswarOdishaIndia

The work investigates the major solute chemistry of groundwater and fluoride enrichment(F^(-))in the shallow phreatic aquifer of *** study also interprets the hydrogeochemical processes of solute acquisition and the genetic behavior of groundwater F^(-)contamination.A total of 1105 groundwater samples collected from across the state from different hydro-geomorphic settings have been analyzed for the major solutes and F^(-) *** is alkaline in nature(range of pH:6.6-8.7;ave.:7.9)predominated by moderately hard to very hard *** cation and anion chemistry stand in the orders of ca^(2+)>na^(+)>Mg^(2+)>K^(+) and HcO_(3)^(-)>cl^(-)>SO_(4)^(2-)>cO_(3)^(2-) *** average mineralization is low(319 mg/L).The primary water types are ca-Mg-HcO_(3) and ca-Mg-cl^(-)HcO_(3),followed by na-cl,ca-Mg-cl,and na-ca-Mg-HcO_(3)^(-)***-halite dissolution and reverse ion exchange are the significant processes of solute *** the geogenic as well as the anthropogenic sources contribute to the groundwater fluoride contamination,*** ratio of na^(+)/ca^(2+)>1.0 comprises na-HcO_(3)(cl)water types with F^(-)>1.0 mg/L(range 1.0-3.5 mg/L)where the F^(-)bears geogenic *** relations exist between F^(-)and pH,na^(+),TDS,and HcO_(3)^(-).It also reflects a perfect na-TDS correlation(0.85).The ratio of na^(+)/ca^(2+)n(F^(-)range:1.0-4.0 mg/L)with the F derived from anthropogenic *** water types include ca-Mg-HcO_(3)(cl)varieties which are recently recharged meteoritic water *** F^(-) levels exhibit poor and negative correlations with the solutes in *** na-TDS relation remains poor(0.12).In contrast,the TDS levels show strong correlations with ca^(2+)(0.91),Mg^(2+)(0.80)and even cl^(-)(0.91).The majority of the monitoring points with the anthropogenic sources of groundwater F^(-) are clustered in the Hirakud canal command area in the western parts of the state,indi

关键词： Groundwater Phreatic Aquifer Quality Odisha India

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characteristics of urban ozone level in Hong kong

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Journal of Environmental Sciences 2001年第1期13卷 1-7页

作者： D.Y.c.LEUnG D.n.ZHAnG Department of Mechanical Engineering The University of Hong KongPokfulam RoadHong KongChina Research Institute of Environmental Engineering East China University of Science and TechnologyShanghai 200237China

The long term trend of ozone level in Hong Kong has been investigated. One of the characteristics of ozone level in Hong Kong is the existence of autumn maximum and summer minimum. Observations of the diurnal variation of ozone level have been made in different area categories. There are early morning peak and afternoon peak occurred in the diurnal variation, which are different from some metropolitans where only an afternoon peak is observed. A negative correlation coefficient was found between monthly ozone level with nitric oxide level. On the contrary, there is a positive correlation between ozone and nitrogen dioxide. The positive correlation coefficient between nitric oxide and nitrogen dioxide shows that the total amount of nitric oxide emitted from a series of moving and fixed sources greatly exceeded the stoichiometric amount of ozone formed from chemical reactions of precursors and long distance transportation.

关键词： ozone urban air pollution Hong kong china

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Denitrification from nitrogen-fixing biologically crusted soils in a cool desert environment,southeast Utah,USA

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Ecological Processes 2013年第1期2卷 156-164页

作者： nichole n Barger Sarah c castle Gavin n Dean Department of Ecology and Evolutionary Biology University of ColoradoCampus Box 334BoulderCO 80309-0334USA Department of Ecosystem and conservation Sciences College of Forestry and ConservationUniversity of MontanaMissoulaMT59812USA.

Introduction:nitrogen fixation by microorganisms within biological soil crust(“biocrust”)communities provides an important pathway for n inputs in cool desert environments where soil nutrients are low and symbiotic n-fixing plants may be *** of n fixation in biocrusts often greatly exceed that of n accretion rates leading to uncertainty regarding n loss ***:In this study we examined nitrogen fixation and denitrification rates in biocrust communities that differed in n fixation potential(low n fixation=light cyanobacterial biocrust,high n fixation=dark cyanolichen crust)at four temperature levels(10,20,30,40°c)and four simulated rainfall levels(0.05,0.2,0.6,1 cm rain events)under controlled laboratory ***:Acetylene reduction rates(AR,an index of n fixation activity)were over six-fold higher in dark crusts relative to light *** biocrusts also exhibited eight-fold higher denitrification *** was no consistent effect of temperature on denitrification rates,but there was an interactive effect of water addition and crust *** light crusts,denitrification rates increased with increasing water addition,whereas the highest denitrification rates in dark crusts were observed at the lowest level of water ***:These results suggest that there are no clear and consistent environmental controls on short-term denitrification rates in these biologically crusted *** together,estimates of denitrification from light and dark biocrusts constituted 3 and 4%of n fixation rates,respectively suggesting that losses as denitrification are not significant relative to n inputs via *** estimate is based on a previously published conversion ratio of ethylene produced to n fixed that is low(0.295),resulting in high estimates of n *** future n fixation studies in biologically crusted soils show that these ratios are closer to the theoretical 3:1 ratio,denitrification may constitute a more significant

关键词： Biological soil crust colorado Plateau cool desert Denitrification nitrogen fixation Soil nitrogen cycling

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convergence Analysis of Iterative Sequences for a Pair of Mappings in Banach Spaces

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Acta Mathematica Sinica,English Series 2008年第3期24卷 463-470页

作者： Liu chuan ZEnG n.c.WOnG J.c.YAO Department of Mathematics Shanghai Normal University Shanghai 200234 P. R. China Department of Applied Mathematics National Sun Yat-Sen University Kaohsiung Taiwan 80424

Let c be a nonempty closed convex subset of a real Banach space E. Let S ： c→ c be a quasi-nonexpansive mapping, let T ： c→c be an asymptotically demicontractive and uniformly Lipschitzian mapping, and let F ：= {x ∈c ： Sx = x and Tx = x}≠Ф Let {xn}n≥0 be the sequence generated irom an arbitrary x0∈cby xn＋i=（1-cn）Sxn＋cnT^nxn, n≥*** prove the necessary and sufficient conditions for the strong convergence of the iterative sequence {xn} to an element of F. These extend and improve the recent results of Moore and nnoli.

关键词： quasi-nonexpansive mapping asymptotically demicontractive type mapping iterative sequence convergence analysis

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Z-scheme mechanism for methylene blue degradation over Fe_(2)O_(3)/g-c_(3)n_(4) nanocomposite prepared via one-pot exfoliation and magnetization of g-c_(3)n_(4)

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Frontiers of Materials Science 2022年第3期16卷 203-218页

作者： Shemeena MULLAKKATTUTHODI Vijayasree HARIDAS Sankaran SUGUnAn Binitha n.nARAYAnAn Department of chemistry Sree Neelakanta Government Sanskrit College(Affiliated to University of Calicut)PattambiPalakkad 679306KeralaIndia Department of Applied chemistry Cochin University of Science and TechnologyCochin 22KeralaIndia Department of chemistry University of CalicutMalappuramKerala 673635India

The low surface area,high recombination rate of photogenerated charge carriers,narrow visible range activity,and difficulty in the separation from cleaned solutions limit the wide application of g-c_(3)n_(4) as a ***,we have succeeded in developing a one-pot strategy to overcome the above-mentioned difficulties of g-c_(3)n_(4).The broadening of the visible-light response range and inducing magnetic nature to g-c_(3)n_(4) was succeeded by preparing a nanocomposite with Fe_(2)O_(3) via a facile solvothermal *** preparation method additionally imparted layer exfoliation of g-c_(3)n_(4) as evident from the XRD patterns and TEM *** strong interaction between the components is revealed from the XPS *** broadened visible-light absorbance of Fe_(2)O_(3)/g-c_(3)n_(4) with a Z-scheme photocatalytic degradation mechanism is well evident from the UV-Vis DRS analysis and PL measurement of the composite with terephthalic *** active species of photocatalysis were further investigated using scavenging studies in methylene blue degradation that revealed hydroxyl radicals and holes as the major contributors to the activity of Fe_(2)O_(3)/g-c_(3)n_(4).

关键词： Fe_(2)O_(3)/g-c_(3)n_(4)nanocomposite Z-scheme photocatalysis magnetic separation dyedegradation

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Phenotypic nutrient up-take differences in an alley cropping system in semi-arid Machakos, Kenya

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Journal of Environmental Sciences 2001年第2期13卷 164-169页

作者： D.n. Mungai c.L.coulson c.J. Stigter J.K. ng’ang’a D.n.Mugendi Department of Geography University of NairobiNairdbiKenya Department of Botany University of NairobiNairobiKenya Department of Enviromnental Sciences Graduate School of Productian EcologyWageningen UniversityDuivendaal 26701 APThe Netherlands Department of Meteorology University of NairobiNairobiKenya Kenya Forestry Research Instiute(KEFRI NairobiKanya)

Alley cropping of cassia siamea and maize was studied in semi arid Kenya for soil fertility improvement. Katumani composite maize was planted except in the short rains of 1988 (SR88) when a hybrid variety was sown. Therefore the grain yield per row increased differently in the alley cropped maize (cM). Sole maize (SM) and cM yields were higher in SR88 than in the long rains of 1988 (LR88) by 62% and 38%, while yields from the same treatments in LR89 were only 21% and 45% of those in SR88 These differences in relative maize yields are attributed to differences between the two maize varieties in competition under nutrient stress conditions.

关键词： alley cropping cassia siamea maize nutrients maize yield semi arid condition soil moisture Kenya

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Ionic liquid-assisted hydrothermal synthesis of SnS nanoparticles:Electrode materials for lithium batteries,photoluminescence and photocatalytic activities

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Journal of Energy chemistry 2018年第3期27卷 806-812页

作者： K.n.Manukumar G.nagaraju Brij Kishore c.Madhu n.Munichandraiah Department of chemistry Siddaganga Institute of TechnologyTumkurKarnatakaIndia Department of Inorganic and Physical chemistry Indian Institute of ScienceBangaloreKarnatakaIndiac Department of Physics.Siddaganga Institute of Technology.Tumkur KarnatakaIndia

Tin mono-sulphide（Sn S） nanoparticles（nps） have been successfully synthesised through ionic liquid assisted hydrothermal method using hydrated tin（II） chloride as a precursor, thiourea as sulphur source precursors using 2-Methoxy ethyl methyl imidazolium methane sulfonate ionic liquid as co-solvent. The Reitveld refinement on powder X-ray diffraction（PXRD） confirmed the presence of orthorhombic Sn S structure as major phase along with traces amount of Sn S2 and Sn2 S3. Diffuse reflectance spectrum studies revealed the energy band gap around 1.38 e V. TEM images confirmed the Sn S nps with average particle size of 40 nm and HRTEM suggest good crystallinity. The electrochemical property for lithium storage behaviour shows an initial discharge capacity of 658 m Ah/g and it retains discharge capacity of 426 m Ah/g for 16 cycles, at current density 100 m A/g. The obtained results indicate that Sn S nps to be one of the possible promising anode materials for next generation Lithium batteries. Photoluminescence study of Sn S nps shows a strong green emission at 530 nm. Sn S nps were also tested for the photocatalytic adsorption of methylene blue and Rhodamine B.

关键词： nanoparticles Lithium-ion batteries Ionic liquids Ionothermal

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Three dimensional free convection couette flow with transpiration cooling

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第3期7卷 340-346页

作者： JAIn n. c. GUPTA P. Department of Mathematics University of Rajasthan Jaipur-302004 India Department of Mathematics Apex Institute of Engineering and Technology Jaipur-302022 India

Free convection flow between two vertical parallel plates with transverse sinusoidal injection of the fluid at the stationary plate and its corresponding removal by constant suction through the plate in uniform motion has been analyzed. Due to this type of injection velocity, the flow becomes three-dimensional. Analytical expressions for the velocity, temperature, skin friction and rate of heat transfer were obtained. The important characteristics of the problem, namely the skin friction and the rate of heat transfer are discussed in detail with the help of graphs.

关键词： couette flow Free convection Three-dimensional flow Transpiration cooling Transverse sinusoidal injection

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The influence of aspect ratio on the properties of cobalt nanowire-based magnetorheological fluids

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International Journal of Smart and nano Materials 2022年第4期13卷 626-642页

作者： R.c Bell n.M Wereley Department of chemistry The Pennsylvania State UniversityAltoona CollegeAltoonaPAUSA Department of Aerospace Engineering University of MarylandCollege ParkMdUSA

The yield stress of magnetorheological(MR)fluids has been shown to depend on particle morphology,but the exact nature of this contribution is still not fully *** this study,MR fluids containing 4 vol.%cobalt particles(spherical particles ***-wires)suspended in silicone oil were *** influence of the aspect ratio on the rheological properties of suspensions that contained cobalt nanowires with aspect ratios ranging from 10 to 101 in increments of~6 is *** cobalt nanowires were fabricated using alumina template-based electrodeposition,produ-cing wires with 305±66 nm *** shear stress was measured as a function of shear rate for increasing applied mag-netic *** apparent yield stress and viscosity as a function of changing aspect ratio of the nanowire suspensions were *** a saturated magnetic flux density,the yield stress was found to increase linearly up to an aspect ratio of 23(7.1μm long wires)at which time the yield stress reached a plateau of 3.7 kPa even as the aspect ratio was further *** a comparison,suspensions containing 4 vol.%1.6μm spherical cobalt particles only reached a maximum yield stress of 1.6 kPa.

关键词： Magnetorheological fluids nanowires size dependence

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Modelling a Learning-Based Dynamic Tree Routing Model for Wireless Mesh Access networks

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computer Systems Science & Engineering 2023年第2期44卷 1531-1549页

作者： n.Krishnammal c.Kalaiarasan A.Bharathi Department of computer Science and Engineering Sri Shakthi Institute of Engineering and TechnologyCoimbatoreIndia School of Engineering Presidency UniversityBengaluruIndia Department of Information Technology Bannari Amman Institute of TechnologySathyamangalamIndia

Link asymmetry in wireless mesh access networks(WMAn)of Mobile ad-hoc networks(MAnETs)is due mesh routers’transmission *** is depicted as signiﬁcant research challenges that pose during the design of network protocol in wireless *** on the extensive review,it is noted that the substantial link percentage is symmetric,i.e.,many links are *** is identiﬁed that the synchronous acknowledgement reliability is higher than the asynchronous ***,the process of establishing bidirectional link quality through asynchronous beacons underrates the link reliability of asym-metric *** paves the way to exploit an investigation on asymmetric links to enhance network functions through link ***,a novel Learning-based Dynamic Tree routing(LDTR)model is proposed to improve network performance and *** the evaluation of delay measures,asymmetric link,interference,probability of transmission failure is *** proportion of energy consumed is used for monitoring energy conditions based on the total energy *** learning model is a productive way for resolving the routing issues over the network model during *** asymmetric path is chosen to achieve exploitation and exploration *** learning-based Dynamic Tree routing model is utilized to resolve the multi-objective routing ***,the simulation is done with MATLAB 2020a simulation environment and path with energy-efﬁciency and lesser E2E delay is evaluated and compared with existing approaches like the Dyna-Q-network model(DQn),asymmetric MAc model(AMAc),and cooperative asymmetric MAc model(cAMAc)*** simulation outcomes demonstrate that the anticipated LDTR model attains superior network performance compared to *** average energy consump-tion is 250 J,packet energy consumption is 6.5 J,PRR is 50 bits/sec,95%PDR,average delay percentage is 20%.

关键词： Wireless mesh access networks mobile ad-hoc network reinforcement learning multi-objective constraint asymmetric link

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