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Multi-scale magnetic resonance measurements and validation of Discrete Element Model simulations

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Particuology 2011年第4期9卷 330-341页

作者： Christoph r. Müller Daniel j. Holland j.mes r. Third Andrew j. sederman j.hn s. Dennis Lynn F. Gladden Institute of Energy Technology Department of Mechanical and Process Engineering Department of Chemical Engineering and Biotechnology University of Cambridge

This short review describes the capabilities of magnetic resonance （Mr） to image opaque single- and two-phase granular systems, such as rotating cylinders and gas-fluidized beds operated in different fluidization regimes. The unique capability of Mr to not only image the solids＇ distribution （voidage） but also the velocity of the particulate phase is clearly shown. It is demonstrated that Mr can provide measurements over different length and time scales. With the Mr equipment used for the studies summarized here, temporal and spatial scales range from sub-millisecond to hours and from a few hundred micrometres to a few centimetres, respectively. Besides providing crucial data required for an improved understanding of the underlying physics of granular flows, multi-scale Mr measurements were also used to validate numerical simulations of granular systems. It is shown that predictions of time-averaged properties, such as voidage and velocity of the particulate phase, made using the Discrete Element Model agree very well with Mr measurements.

关键词： Discrete Element Modelling Magnetic resonance imaging MultiscaleGas-fluidized beds rotating cylinders

Differences in sensitivity of native and exotic fish species to changes in river temperature

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Current Zoology 2011年第6期57卷 852-862页

作者： r.s.E.W. LEUVEN A.j. HENDrIKs M.A.j. HUIj.rEGTs H.j.r. LENDErs j. MATTHEWs VAN DEr VELDE radboud University Nij.egen Institute for Water and Wetland Research Department of Environmental Science Heyendaal- seweg 135 NL-6525 AJ Nijmegen The Netherlands radboud University Nij.egen Institute for Water and Wetland Research Department of Animal Ecology and Ecophysiology Heyendaalseweg 135 NL-6525 AJ Nijmegen The Netherlands Netherlands Centre for Biodiversity Naturalis P.O. Box 9517 NL-2300 RA Leiden The Netherlands

This paper describes the effects that temperature changes in the rhine river distributaries have on native and exotic fish diversity. site-specific potentially affected fractions （PAFs） of the regional fish species pool were derived using species sensitivity distributions （ssDs） for water temperature. The number of fish species in the river distributaries has changed remarkably over the last century. The number of native rheophilous species declined up until 1980 due to anthropogenic disturbances such as commercial fishing, fiver regulation, migration barriers, habitat deterioration and water pollution. In spite of progress in river re- habilitation, the native rheophilous fish fauna has only partially recovered thus far. The total number of species has strongly in- creased due to the appearance of more exotic species. After the opening of the rhine-Main-Danube waterway in 1992, many fish species originating from the Ponto-Caspian area colonized the rhine basin. The yearly minimum and maximum river tempera- tures at Lobith have increased by circa 4 ~C over the period 1908-2010. Exotic species show lower PAFs than native species at both ends of the temperature range. The interspecific variation in the temperature tolerance of exotic fish species was found to be large. Using temporal trends in river temperature allowed past predictions of PAFs to demonstrate that the increase in maximum river temperature negatively affected a higher percentage of native fish species than exotic species. Our results support the hy- pothesis that alterations of the river rhine＇s temperature regime caused by thermal pollution and global wanning limit the full recovery of native fish fauna and facilitate the establishment of exotic species which thereby increases competition between native and exotic species. Thermal refuges are important for the survival of native fish species under extreme summer or winter temperature conditions

关键词： Aquatic invaders Global warming Heat discharges Lethal temperature river rhine Thermal heterogeneity

A Novel Training Algorithm of Genetic Neural Networks and Its Application to Classification

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j.urnal of systems Engineering and Electronics 2001年第3期12卷 76-84页

作者： Xiao, j. Wu, j. Yang, s. school of Mechanics Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

First of all, this paper discusses the drawbacks of multilayer perceptron (MLP), which is trained by the traditional back propagation (BP) algorithm and used in a special classification problem. A new training algorithm for neural networks based on genetic algorithm and BP algorithm is developed. The difference between the new training algorithm and BP algorithm in the ability of nonlinear approaching is expressed through an example, and the application foreground is illustrated by an example.

关键词： Backpropagation Computer simulation Genetic algorithms Mathematical models Nonlinear control systems Problem solving

Performance investigation of artificial intelligence based controller for three phase four leg shunt active filter

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Frontiers in Energy 2015年第4期9卷 446-460页

作者： j. j.YACHANDrAN r. MUrALI sACHITHANANDAM Department of Electrical and Electronics Engineering SASTRA University Thanjavur 613401 India

In this paper, the choice of power quality compensator is a DsTATCOM which constitutes a three phase four leg voltage source converter （VsC） with a DC capacitor. The control strategy proposed for the DsTAT- COM is a neural network based one cycle control （OCC）. This control strategy involves neural network block, digital circuits and linear elements, which eliminates the sensors required for sensing the load current and coupling inductor current in addition to the multiplier employed in the conventional method. The calculation of harmonic and reactive currents for the reference current generation is also eliminated, thus minimizing the complexity in the control strategy. The control strategy mitigates harmonic/reactive currents, ensures balanced and sinusoidal source current from the supply mains that are nearly in phase with the supply voltage, compensates neutral current, and maintains voltage across the capacitor under unbalanced source and load conditions. The performance of the DsTATCOM with the proposed artificial neural network （ANN） controllers is validated and investigated through simulations using Matlab software. The simulation results prove the efficacy of the proposed neural network based control strategy under varying source and load conditions.

关键词： neural network DsTATCOM neutral currentmitigation total harmonic distortion (THD) three phasefour wire distribution system unbalanced and/or distortedsource

Antifertility effects of methanolic pod extract of Albizzia lebbeck (L.) Benth in male rats

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Asian j.urnal of Andrology 2004年第2期6卷 155-159页

作者： r. s. Gupta j. B. s.Kachhawa r. Chaudhary reproduction Physiology section Department of Zoology University of Rajasthan Jaipur-302 004 IndiaReproduction Physiology Section Department of Zoology University of Rajasthan Jaipur-302 004 IndiaReproduction Physiology Section Department of Zoology University of Rajasthan Jaipur-302 004 India

Aim: To evaluate the antifertility activity of the methanolic pod extract of Albizzia lebbeck (L.) Benth in male albino rats. Methods: The methanolic pod extract of Albizzia lebbeck was administrated orally for 60 days at 50, 100 and 200 mg·kg-1·day-1 to male albino rats. sperm motility and density in cauda epididymides were assessed. Biochemical and histological analysis were performed in blood samples and reproductive organs. results: A. lebbeck pod extract brought about a significant decrease in the weights of testis, seminal vesicles, epdidymis and ventral prostate. The sperm motility and density were significantly reduced. There was a marked reduction in the numbers of primary spermatocytes, secondary spermatocytes and spermatids. The sertoli cell count as well as its cross sectional surface area were significantly decreased. The Leydig cell nuclear area and the number of mature Leydig celis were also significantly decreased. The protein, glycogen and cholesterol content of the testis, the fructose in the seminal vesicles and protein in the epididymis were significantly decreased. The rBC and WBC counts, haemoglobin, haematocrit and blood sugar were within the normai range. Conclusion: The methanolic extract of A. lebbeck pods causes spermatogenic arrest in male albino rats.

关键词： Albizzia lebbeck sertoli celis spermatogonia spermatocytes leydig celis

Morphological, Physical, Mechanical, Chemical and Thermal Characterization of sustainable Indian Areca Fruit Husk Fibers （Areca Catechu L.） as Potential Alternate for Hazardous synthetic Fibers

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j.urnal of Bionic Engineering 2016年第1期13卷 156-165页

作者： j. s. Binoj.r. Edwin raj.V. s. sreenivasan C. rexin Thusnavis Department of Mechanical Engineering St. Xavier' s Catholic College of Engineering Nagercoil - 629003 India Department of Mechanical Engineering VV College of Engineering Tisaiyanvilai - 627657 India Department of Chemistry St. Xavier' s Catholic College of Engineering Nagercoil - 629003 lndia

Natural fibers can play a maj.r role in composite industry due to its renewable, biodegradable, and eco-friendly properties. Areca Fruit Husk （AFH） is rich in fiber, but is wasted in large quantity from tobacco industries. Comprehensive characterization of AFH fiber is done to examine its morphological, physical, mechanical, chemical and thermal properties. High cellulose content of the fiber （57.35 wt%） provides better tensile strength （231.66 MPa） whereas the porous surface morphology （40.8 %） ensures better bonding with the matrix. Moreover, the low density of the fiber （0.78 ***^-3） makes it an attractive alternative for hazardous synthetic fibers. The semi-crystalline nature and large crystalline size of the fiber reduce the water absorption char- acteristics. The thermo gravimetric analysis confirms its stability up to 240℃, which is higher than the polymerization tem- perature. The results confirm the potential of AFH fibers as a reinforcement in bio-reinforced polymer composites for automo- tive and structural applications.

关键词： bio-reinforced polymer composites Areca husk fibers physical properties chemical properties

The nature of the companion of Psr j.719-1438: a white dwarf or an exotic obj.ct?

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research in Astronomy and Astrophysics 2012年第7期12卷 813-816页

作者： j. E. Horvath Instituto de Astronomia Geofísica e Ciências Atmosfricas - Universidade de So Paulo

We raise the possibility that the very dense, compact companion of Psr j.719-1438, which has a j.piter-like mass, is an exotic quark obj.ct rather than a light helium or carbon white dwarf. The exotic hypothesis naturally explains some of the observed features, and provides quite strong predictions for this system, to be confirmed or refuted in feasible future studies.

关键词： binary pulsars -- exotic matter-- pulsars: individual (Psr j.719-1438)

Nonlinear three-dimensional stretched flow of an Oldroyd-B fluid with convective condition, thermal radiation, and mixed convection

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Applied Mathematics and Mechanics(English Edition) 2017年第7期38卷 969-980页

作者： B. MAHANTHEsH B. j. GIrEEsHA s.A. sHEHZAD F.M. ABBAsI r. s. r. GOrLA Department of Mathematics Christ University Bangalore 560029 Karnataka India Department of studies and research in Mathematics Kuvempu University Shankarghatta 577451 Karnataka India Department of Mathematics COMSATS Institute of Information Technology Sahiwal 57000 Pakistan Department of Mathematics COMSATS Institute of Information Technology Islamabad 44000 Pakistan Department of Mechanical and Civil Engineering Purdue University Northwest Indiana 46391 U. S. A

The effect of non-linear convection in a laminar three-dimensional Oldroyd-B fluid flow is addressed. The heat transfer phenomenon is explored by considering the non-linear thermal radiation and heat generation/absorption. The boundary layer as- sumptions are taken into account to govern the mathematical model of the flow analy- sis. some suitable similarity variables are introduced to transform the partial differen- tial equations into ordinary differential systems. fifth-order techniques with the shooting method The runge-Kutta-Fehlberg fourth- and are used to obtain the solutions of the dimensionless velocities and temperature. The effects of various physical parameters on the fluid velocities and temperature are plotted and examined. A comparison with the exact and homotopy perturbation solutions is made for the viscous fluid case, and an excellent match is noted. The numerical values of the wall shear stresses and the heat transfer rate at the wall are tabulated and investigated. The enhancement in the values of the Deborah number shows a reverse behavior on the liquid velocities. The results show that the temperature and the thermal boundary layer are reduced when the non- linear convection parameter increases. The values of the Nusselt number are higher in the non-linear radiation situation than those in the linear radiation situation.

关键词： nonlinear thermal convection nonlinear thermal radiation Oldroyd-B fluid,convective boundary condition heat source/sink

A systematic review of progenitor survival and maturation in Parkinsonian models

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Neural regeneration research 2025年第11期20卷 3172-3178页

作者： Giulia Comini Eilís Dowd Pharmacology&Therapeutics and Galway Neuroscience Center University of GalwayGalwayIreland

stem cell-based brain repair is a promising emergent therapy for Parkinson's disease based on years of foundational research using human fetal donors as a cell *** current therapeutic options for patients,this approach has the potential to provide longterm stem cell–derived reconstruction and restoration of the dopaminergic input to denervated regions of the brain allowing for restoration of certain functions to *** ultimate clinical success of stem cell–derived brain repair will depend on both the safety and efficacy of the approach and the latter is dependent on the ability of the transplanted cells to survive and differentiate into functional dopaminergic neurons in the Parkinsonian *** the pre-clinical literature suggests that there is considerable variability in survival and differentiation between studies,the aim of this systematic review was to assess these parameters in human stem cell-derived dopaminergic progenitor transplant studies in animal models of Parkinson's disease.A defined systematic search of the PubMed database was completed to identify relevant studies published up to March *** screening,76 articles were included in the analysis from which 178 separate transplant studies were *** these,graft survival could be assessed in 52 studies and differentiation in 129 ***,we found that graft survival ranged froms transplanted,with a median of 51%of transplanted cells surviving in the brain;while dopaminergic differentiation of the cells ranged from 0% to 46% of cells transplanted with a median of 3%.This systematic review suggests that there is considerable scope for improvement in the differentiation of stem cell-derived dopaminergic progenitors to maximize the therapeutic potential of this approach for patients.

关键词： cell replacement therapy differentiation embryonic stem cells graft induced pluripotent stem cells Parkinson's disease survival transplant