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Macro and micro issues in turbulent mixing

Science China(Technological Sciences) 2013年第10期56卷 2355-2360页

作者： MELVIN J KAUFMAN r LIM H KAMAN T rao P GLIMM J Department of Applied Mathematics and Statistics Stony Brook UniversityStony Brook NY 11794 USA

Numerical prediction of turbulent mixing can be divided into two subproblems: to predict the geometrical extent of a mixing region and to predict the mixing properties on an atomic or molecular scale, within the mixing region. The former goal suffices for some purposes, while important problems of chemical reactions(e.g. flames) and nuclear reactions depend critically on the second goal in addition to the first one. Here we review recent progress in establishing a conceptual reformulation of convergence, and we illustrate these concepts with a review of recent numerical studies addressing turbulence and mixing in the high reynolds number limit. We review significant progress on the first goal, regarding the mixing region, and initial progress on the second goal, regarding atomic level mixing properties. New results concerning non-uniqueness of the infinite reynolds number solutions and other consequences of a renormalization group point of view, to be published in detail elsewhere, are summarized *** notion of stochastic convergence(of probability measures and probability distribution functions) replaces traditional pointwise convergence. The primary benefit of this idea is its increased stability relative to the statistical "noise" which characterizes turbulent flow. Our results also show that this modification of convergence, with sufficient mesh refinement, may not be needed. However, in practice, mesh refinement is seldom sufficient and the stochastic convergence concepts have a *** to this circle of ideas is the observation that turbulent mixing, in the limit of high reynolds number, appears to be non-unique. Not only have multiple solutions been observed(and published) for identical problems, but simple physics based arguments and more refined arguments based on the renormalization group come to the same *** of the non-uniqueness inherent in numerical models of high reynolds number turbulence and mixing, we also include here numeri

关键词： stochastic convergence turbulent mixing renormalization group dynamic subgrid scale models

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Instrumental neutron activation analysis of beachrock samples of South East Coast of Tamilnadu,India

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Nuclear Science and Techniques 2007年第4期18卷 204-211页

作者： r.rAVISANKAr P.ESWArAN N.P.SESHADErSSAN Bramaji rao Department of Physics Sri Siva Subramania Nadar College of EngineeringKalvakkam Chennai-603110Tamilnadu India Department of Physics SMK Fomra Institute of TechnologyThaiyurChennai-603 103Tamilnadu Nuclear Chemistry Section Chemistry GroupsIndira Gandhi Centre for Atomic Research (IGCAR)Kalpakkam-603 102TamilnaduIndia

Element profiles of some beach rock samples collected from South East Coast of Tamilnadu, India have been determined using single comparator method of INAA. The geo-chemical behavior of the elements in the region is discussed. The irradiations were done at thermal neutron flux of ~ 1011 cm-2·s-1 at 20kW power using Kalpakkam Mini reactor (KAMINI), IGCAr, Kalpakkam, Tamilnadu, India. Around 19 elements have been determined from 15 samples by high-resolution gamma spectrometry. The accuracy and precision were evaluated by assaying the irradiated Standard reference Material (SrM 1646a Estuarine sediment) and were found to be in good agreement with certified values.

关键词：中子激活分析 KAMANI反应器岩石

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Enhancing Security by Using GIFT and ECC Encryption Method in Multi-Tenant Datacenters

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Computers, Materials & Continua 2023年第5期75卷 3849-3865页

作者： Jin Wang Ying Liu Shuying rao r.Simon Sherratt Jinbin Hu School of Computer&Communication Engineering Changsha University of Science&TechnologyChangsha410004China School of Systems Engineering The University of ReadingRG66AYUK

Data security and user privacy have become crucial elements in multi-tenant data *** traffic types in the multi-tenant data center in the cloud environment have their characteristics and *** the data center network(DCN),short and long flows are sensitive to low latency and high throughput,*** traditional security processing approaches,however,neglect these characteristics and *** paper proposes a fine-grained security enhancement mechanism(SEM)to solve the problem of heterogeneous traffic and reduce the traffic completion time(FCT)of short flows while ensuring the security of multi-tenant traffic ***,for short flows in DCN,the lightweight GIFT encryption method is *** Intra-DCN long flows and Inter-DCN traffic,the asymmetric elliptic curve encryption algorithm(ECC)is *** NS-3 simulation results demonstrate that SEM dramatically reduces the FCT of short flows by 70%compared to several conventional encryption techniques,effectively enhancing the security and anti-attack of traffic transmission between DCNs in cloud computing ***,SEM performs better than other encryption methods under high load and in largescale cloud environments.

关键词： Multi-tenant datacenter user privacy transmission security GIFT ECC

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Hepatoprotective and antioxidant capacity of Melochia corchorifolia extracts

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Asian Pacific Journal of Tropical Medicine 2013年第7期6卷 537-543页

作者： B Ganga rao Y Venkateswara rao T Mallikarjuna rao A.U College of Pharmaceutical Sciences Andhra UniversityVisakhapatnamAndhra PradeshIndia-530003 Department of Botany College of Science and TechnologyAndhra University.VisakhapatnamAndhra PradeshIndia-530003

Objective:To evaluate bepato protective and antioxidant capacity of Melochia corchorifolia （***）aerial part ***:Antioxidant activitywas evaluated by using three free radicals（Superoxide,Hydroxyl and DPPH） and hepatoprotective activity was assessed against CCl4 induced liver intoxication in ***:The extracts produced concentration dependent percentage protection in decrease of serum enzymes and percentage inhibition on free *** all extracts methanol extract showed better activity with percentage protection of SGOT（78.98%）,SGPT（79.65%）,ALP（82.48%） and total bilirubin（80.0%）levels against CCl4 liver intoxication and also methanolic extract showed better activity with IC50 values on superoxide. hydroxyl and DPPH radicals were 127μg.240μg and 179μ***:From the results obtained during the study it could be concluded that *** aerial part extracts have antioxidant and hepaloprotective *** study is necessary for isolation and characterization of bioactive molecules which are responsible for hepatoprotective and antioxidant activity.

关键词： Melochia corchorifolia Aerial parts Free radicals Antioxidant Activity CCl_4 Hepatoprotective activity

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Optimizing machining parameters of wire-EDM process to cut Al7075/SiCp composites using an integrated statistical approach

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Advances in Manufacturing 2016年第3期4卷 202-216页

作者： Thella Babu rao Department of Mechanical Engineering K L UniversityGreen Fields Vaddeswaram GunturAndhra Pradesh 522502 India

Metal matrix composites （MMCs） as advanced materials, while producing the components with high dimensional accuracy and intricate shapes, are more complex and cost effective for machining than conventional alloys. It is due to the presence of discontinuously distributed hard ceramic with the MMCs and involvement of a large number of machining control variables. However, determination of optimal machining conditions helps the process engineer to make the process efficient and effec- tive. In the present investigation a novel hybrid multi-response optimization approach is proposed to derive the economic machining conditions for MMCs. This hybrid approach integrates the concepts of grey relational analysis （GrA）, principal component analysis （PCA） and Taguchi method （TM） to derive the optimal machining conditions. The machining experiments are planned to machine A17075/SiCp MMCs using wire-electrical discharge machining （WEDM） process. SiC particulate size and its weight percentage are explicitly considered here as the process variables along with the WEDM input variables. The derived optimal process responses are confirmed by the experimental validation tests and the results show satisfactory. The practical possibility of the derived optimal machining conditions is also analyzed and presented using scanning electron microscope （SEM） examinations. According to the growing industrial need of making high performance, low cost components, this investigation provides a simple and sequential approach to enhance the WEDM performance while machining MMCs.

关键词： Al7075/SiCP metal matrix composites(MMCs) Wire-electrical discharge machining (WEDM)Principal component analysis (PCA) Grey relationalanalysis (GrA) Taguchi method (TM)

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Simultaneous allocation of renewable energy sources and custom power quality devices in electrical distribution networks using artificial rabbits optimization

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Clean Energy 2023年第4期7卷 795-807页

作者： ranga rao Chegudi Balamurugan ramadoss ramakoteswara rao Alla Department of Electrical Engineering Faculty of Engineering and TechnologyAnnamalai UniversityChidambaramTamilnadu 608002India Department of EEE RVR&JC College of EngineeringGunturAndhra Pradesh 522019India

This study suggests an optimal renewable energy source(rES)allocation and distribution-static synchronous compensator(D-STATCOM)and passive power filters(PPFs)for an electrical distribution network(EDN)to improve its performance and power quality(PQ).First,the latest metaheuristic artificial rabbits optimization(ArO)is used to locate and size solar photovoltaic(PV),wind turbine(WT)and D-STATCOM *** the second stage,ratings of single-tuned PPFs and D-STATCOMs at the rESs are determined,considering non-linear loads in the *** multi-objective function reduces power loss,improves the voltage stability index(VSI)and limits total harmonic *** using the IEEE 33-bus EDN compared the ArO results with those of previous *** the first scenario,ideally integrated D-STATCOMs,PVs and WTs reduced losses by 34.79%,64.74%and 94.15%,*** increases from 0.6965 to 0.7749,0.8804 and *** optimal WT integration of the first scenario outperformed the PVs and *** second step optimizes the WTs and PQ devices for non-linear *** and D-STATCOMs reduce the maximum total harmonic distortion of the voltage waveform by 5.21%with non-linear loads to 3.23%,while WTs and PPFs reduce it to 4.39%.These scenarios demonstrate how WTs and D-STATCOMs can improve network performance and *** computational efficiency of ArO is compared to that of the pathfinder algorithm,future search algorithm,butterfly optimization algorithm and coyote optimization *** speeds up convergence and improves solution quality and comprehension.

关键词： artificial rabbits optimization renewable distribution generation D-STATCOM power quality improvement loss reduction voltage stability enhancement

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Uniqueness of Solution to Systems of Elliptic Operators and Application to Asymptotic Synchronization of Linear Dissipative Systems Ⅱ: Case of Multiple Feedback Dampings

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Chinese Annals of Mathematics,Series B 2022年第5期43卷 659-684页

作者： Tatsien LI Bopeng rao School of Mathematical Sciences Fudan UniversityShanghai 200433China Shanghai Key Laboratory for Contemporary Applied Mathematic Nonlinear Mathematical Modeling and Methods Laboratory Shanghai 200433China Institut de recherche Mathematique Avancee Universitede Strasbourg67084 StrasbourgFrance

In this paper,the authors consider the asymptotic synchronization of a linear dissipative system with multiple feedback *** first show that under the observability of a scalar equation,Kalman’s rank condition is sufficient for the uniqueness of solution to a complex system of elliptic equations with *** authors then establish a general theory on the asymptotic stability and the asymptotic synchronization for the corresponding evolutional system subjected to mixed dampings of various *** classic models are presented to illustrate the field of applications of the abstract theory.

关键词： Kalman rank condition Uniqueness Asymptotic synchronization Kelvin-Voigt damping

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Enhanced solar-light-driven photocatalytic properties of novel Z-scheme binary BiPO_(4)nanorods anchored onto NiFe_(2)O_(4)nanoplates:Efficient removal of toxic organic pollutants

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Journal of Environmental Sciences 2021年第4期33卷 326-340页

作者： ravindranadh Koutavarapu Mohan rao Tamtam Chimpiri rao Myla Migyung Cho Jaesool Shim School of Mechanical Engineering Yeungnam UniversityGyeongsan 712-749Republic of Korea Chemical Engineering Department Debre Berhan UniversityDebre Berhan 445Ethiopia Department of Physics Andhra Loyola CollegeVijayawada 520-008Andhra PradeshIndia Department of Computer and Media Engineering Tongmyong UniversityBusan 48520Republic of Korea

Global environmental problems have been increasing with the growth of the world economy and have become a crucial *** replace fossil fuels,sustainable and eco-friendly catalysts are required for the removal of organic *** this study,nickel ferrite(NiFe_(2)O_(4))was prepared using a simple wet-chemical synthesis,followed by calcination;bismuth phosphate(BiPO_(4))was also prepared using a hydrothermal ***,NiFe_(2)O_(4)/BiPO_(4)nanocomposites were prepared using a hydrothermal *** characterization studies,such as structural,morphology,surface area,optical,photoluminescence,and photoelectrochemical investigations,were used to analyze NiFe_(2)O_(4)/BiPO_(4)*** morphology analysis indicated a successful decoration of BiPO_(4)nanorods on the surface of Ni Fe_(2)O_(4)***,the bandgap of the NiFe_(2)O_(4)/BiPO_(4)nanocomposites was modified owing to the formation of a *** as-prepared NiFe_(2)O_(4)/BiPO_(4)nanocomposite exhibited promising properties to be used as a novel heterostructure for tetracycline(TC)and rhodamine B(rh B)*** NiFe_(2)O_(4)/BiPO_(4)nanocomposite degrades TC(98%)and rh B(99%)pollutants upon solar-light irradiation within 100 and 60 min,***,the trapping experiments confirmed the Z-scheme approach of the prepared *** efficient separation and transfer of photogenerated electron-hole pairs rendered by the heterostructure were confirmed by utilizing electrochemical impedance spectroscopy,photocurrent experiments,and ***–Schottky measurements were used determine the positions of the conduction and valence bands of the samples,and the detailed mechanism of photocatalytic degradation of toxic pollutants was projected and discussed.

关键词： Nickel ferrite Bismuth phosphate Heterostructure Z-scheme Tetracycline Photocatalysis

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runoff variations in the Yangtze river Basin and sub-basins based on GrACE, hydrological models, and in-situ data

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Earth and Planetary Physics 2022年第3期6卷 228-240页

作者： WeiLong rao WenKe Sun University of Chinese Academy of Sciences Beijing 100049China

Water budget closure is a method used to study the balance of basin water storage and the dynamics of relevant hydrological components(e.g.,precipitation,evapotranspiration,and runoff).When water budget closure is connected with terrestrial water storage change(TWSC)estimated from Gravity recovery and Climate Experiment(GrACE)data,variations in basin runoff can be understood *** this study,total runoff variations in the Yangtze river Basin(YrB)and its sub-basins are examined in detail based on the water budget closure *** compare and combine mainstream precipitation and evapotranspiration models to determine the best estimate of precipitation minus *** addition,we consider human water consumption,which has been neglected in earlier studies,and discuss its *** evaluate the effectiveness and accuracy of the combined hydrological models in estimating subsurface runoff,we collect discharge variations derived from in situ observations in the YrB and its sub-basins and compare these data with the models’final estimated runoff *** estimated runoff variations suggest that runoff over the YrB has been increasing,especially in the lower sub-basins and in the post-monsoon season,and is accompanied by apparent terrestrial water loss.

关键词： runoff discharge Yangtze river Basin water budget closure GrACE

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Effect of magnetic flux advection on the dynamics of shock in accretion flow around a rotating black hole

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research in Astronomy and Astrophysics 2020年第3期20卷 150-161页

作者： Biplob Sarkar Anjali rao Faculty of Science&Technology The ICFAI University TripuraAgartala799210India Department of Physics and Astronomy University of Southampton.Highfield.Southampton SO 171BJUK Department of Applied Sciences Tezpur UniversityNapaam-784028.TezpurAssamIndia

We investigate the dynamical behavior of a magnetized,dissipative accretion flow around a rapidly rotating black *** solve the magnetohydrodynamic equations and calculate the transonic accretion solutions which may contain discontinuous shock *** investigate the effect ofζ-parameter(parametrizing the radial variation of the toroidal magnetic flux advection rate)on the dynamical behavior of *** a rapidly rotating black hole and for fixed injection parameters at the outer edge,we show that stationary shocks are sustained in the global magnetized accretion solutions for a wide range ofζand accretion rate(˙m).To investigate the observational implications,we consider dissipative shocks and estimate the maximum accessible energy from the post-shock corona(PSC)for nine stellar mass black hole *** compare this with the observed radio jet kinetic power reported in the literature,whenever *** find close agreement between the estimated values from our model and those reported in the literature.

关键词： accretion,accretion discs-magnetohydrodynamics-stars black holes-shock waves-ISM jets and outflows

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