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Metallographic Analyses of Laser Gladded Wc-Ni and Wc-co Hard-facing Metals

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材料热处理学报 2004年第5期 996-999页

作者： HK chikwanda,M chiremba,c van rooyen Department of chemical &Metallurgical Engineering Tshwane University of Technology Pretoria South Africa. Department of chemical &Metallurgical Engineering Tshwane University of Technology Pretoria South Africa. National Laser centre cSIR Pretoria South Africa

关键词： Laser cladding clad layer substrate metal dilution clad height clad depth.

Supporting consistency in Linked Specialized Engineering Models Through Bindings and Updating

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Tsinghua Science and Technology 2008年第S1期13卷 165-170页

作者： Albertus H. Olivier Gert c. van rooyen Berthold Firmenich Karl E. Beucke cAD in der Bauinformatik Department of Civil Engineering Bauhaus-University Weimar civil Engineering Informatics Department of Civil Engineering University of Stellenbosch Informatik im Bauwesen Department of Civil Engineering Bauhaus-University Weimar

currently, some commercial software applications support users to work in an integrated environment. However, this is limited to the suite of models provided by the software vendor and consequently it forces all the parties to use the same software. In contrast, the research described in this paper investigates ways of using standard software applications, which may be specialized for different professional domains. These are linked for effective transfer of information and a binding mechanism is provided to support consistency. The proposed solution was implemented using a cAD application and an independent finite element application in order to verify the theoretical aspects of this work.

关键词： cAD/FEM integration structural engineering model consistency support binding mechanism

Metallographic Analyses of Laser cladded Wc-Ni and Wc-co Hard-facing Metals

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Metallographic Analyses of Laser Cladded WC-Ni and WC-Co Har...

Impaired Pulmonary Function as a Potential contributor to Reduced Exercise capacity Associated with MAFLD

14～(th) congress of International Federation for Heat Treament and Surface Engineering

作者： HK chikwanda M chiremba c van rooyen Department of chemical ＆ Metallurgical Engineering Tshwane University of TechnologyPretoria South Africa Department of chemical ＆ Metallurgical Engineering Tshwane University of TechnologyPretoria South Africa National Laser centre CSIRPretoria South Africa

＜正＞ Laser cladding is performed to improve the surface properties of metallic machine components. Extensive work is being conducted to investigate the relationships among the cladding parameters, clad powder characteristics and the quality of the clad layer. This work presents some of the metallographic analyses results of Wc -Ni and Wc-co clad layers. The clad layers are characterised with non-uniform carbide particles, mostly Wc imbedded in a more ductile matrix. The transition from the clad layer to the substrate metal had a distinct dilution zone. The ratio of this zone to the clad height was in the range of 10 -12% and this still needs to be refined.

关键词： Laser cladding clad layer substrate metal dilution clad height clad depth.

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Journal of clinical and Translational Hepatology 2022年第2期10卷 181-183页

作者： Derrick Michael van rooyen Oyekoya Taiwo Ayonrinde Department of Gastroenterology and Hepatology Fiona Stanley HospitalMurdochWAAustralia Medical School The University of Western AustraliaNedlandsAustralia Faculty of Health Sciences Curtin UniversityBentleyAustralia

For over a century,fatty liver has been associated with inadequate physical activity.1 A sedentary lifestyle has long been considered a major contributor to obesity and fatty *** with fatty liver are consequently often deemed to be unwilling or unable to increase their physical activity as a therapeutic lifestyle *** is ongoing toward identifying obstacles to physical exercise in people with fatty liver,exposing intrinsic and extrinsic factors that may sometimes be bidirectional.

关键词： obesity identifying willing

Novel microsatellite markers suggest the mechanism of parthenogenesis in Extatosoma tiaratum is automixis with terminal fusion

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Insect Science 2018年第1期25卷 24-32页

作者： Yasaman Alavi Anthony van rooyen Mark Adrian Elgar Theresa Melanie Jones Andrew Raymond Weeks1 School of BioSciences University of Melbourne Victoria Australia cesar Pty Ltd 293 Royal Parade Parkville Victoria Australia

Parthenogenetic reproduction is taxonomically widespread and occurs through various cytological mechanisms, which have different impact on the genetic variation of the offspring. Extatosoma tiaratum is a facultatively parthenogenetic Australian insect （Phasmatodea）, in which females oviposit continuously throughout their adult lifespan irre- spective of mating. Fertilized eggs produce sons and daughters through sexual reproduction and unfertilized eggs produce female offspring via parthenogenesis. Here, we developed novel microsatellite markers for E. tiaratum and characterized them by genotyping indi- viduals from a natural population. We then used the microsatellite markers to infer the cytological mechanism of parthenogenesis in this species. We found evidence suggesting parthenogenesis in E. tiaratum occurs through automixis with terminal fusion, resulting in substantial loss of microsatellite heterozygosity in the offspring. Loss of microsatel- lite heterozygosity may be associated with loss of heterozygosity in fitness related loci. The mechanism of parthenogenetic reproduction can therefore affect fitness outcomes and needs to be considered when comparing costs and benefits of sex versus parthenogenesis.

关键词： apomixis automixis Extatosoma tiaratum heterozygosity microsatellite markers parthenogenesis

Modeling the effects of salt concentration on aqueous and organic electrolytes

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npj computational Materials 2023年第1期9卷 546-552页

作者： Stephanie c.c.van der Lubbe Pieremanuele canepa Department of Materials Science and Engineering National University of Singapore9 Engineering Drive 1117575 SingaporeSingapore Department of chemical and Biomolecular Engineering National University of Singapore4 Engineering Drive 4117585 SingaporeSingapore Department of Electrical and computer Engineering and Texas center for Superconductivity University of HoustonHoustonTX 77204USA

Understanding the thermodynamic properties of electrolyte solutions is of vital importance for a myriad of physiological and technological *** mean activity coefficientγ±is associated with the deviation of an electrolyte solution from its ideal behavior and may be obtained by combining the Debye-Hückel(DH)and Born(B)***,the DH and B equations depend on the concentration and temperature-dependent static permittivity of the solutionεr(c,T)and the size of the solvated ions ri,whose experimental data is often not ***,we use a combination of molecular dynamics and density functional theory to predictεr(c,T)and ri,which enables us to apply the DH and B equations to any technologically relevant aqueous and nonaqueous electrolyte at any concentration and temperature of interest.

关键词： equations electrolyte apply

Pointed p^3-Dimensional Hopf Algebras in Positive characteristic

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Algebra colloquium 2018年第3期25卷 399-436页

作者： van c. Nguyen Xingting Wang Department of Mathematics Hood College Frederick MD 21701 USA Department of Mathematics Howard University Washington DC 20059 USA

We focus on the classification of pointed p^3-dimensional Hopf algebras H over any algebraically closed field of prime characteristic p 〉 0. In particular, we consider certain cases when the group of grouplike elements is of order p or p^2 that is, when H is pointed but is not connected nor a group algebra. The structures of the associated graded algebra gr H are completely described as bosonizations of graded braided Hopf algebras over group algebras, and most of the lifting structures of H are given. This work provides many new examples of （parametrized） non-commutative, non-cocommutative finite- dimensional Hopf algebras in positive characteristic.

关键词： braided Hopfalgebras Yetter-Drinfeld modules positive characteristic pointed Hopf algebras Nichols algebras

critical movement of large rocks in currents and waves

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International Journal of Sediment Research 2019年第4期34卷 387-398页

作者： L.c.van Rijn LVR-Sediment consultancy

cobbles, boulders, and rocks often are used in a bed protection layer near a structure to protect the underlying sand bed against erosion by combined current and waves. The design of a bed protection layer consisting of loose rocks(rubble mound) requires knowledge of the stability and movement(as bed load) of very coarse materials. If some movement(or damage) is acceptable, the rock diameter can be designed to be smaller. This paper addresses the stability and movement of very coarse materials(cobbles, boulders, and rocks) based on the concept of the critical Shields mobility number. It is shown that the bed load transport of large cobbles, boulders, and rocks can be described by the equations of Meyer-Peter and Mueller(MPM) and cheng. Both are valid for relatively small Shields mobility *** and general equations for the design of a bed protection layer(including some permissible damage)in conditions with a current with or without waves are proposed based on the Shields mobility parameter and the bed load transport equation of cheng. Laboratory and field data of critical velocities for pebbles, cobbles, boulders, and rocks have been analyzed and compared to the computed results of the proposed equations. Practical applications are given to demonstrate the general applicability of the proposed equations.

关键词： Rock stability Bed protection critical movement Bed load transport Rocks

Dispersal of invasive species by drifting

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current Zoology 2011年第6期57卷 818-827页

作者： M.c. van RIEL G. van DER VELDE A. BIJ DE VAATE Radboud University Nijmegen Institute for Water and Wetland Research Department of Animal Ecology and Ecophysiology Section Aquatic Animal Ecology Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands Team Freshwater Ecology DLO-Alterra P.O. Box 47 6700 AA Wageningen The Netherlands Netherlands centre for Biodiversity Naturalis EO. Box 9517 2300 RA Leiden The Netherlands Waterfauna Hydrobiologisch Adviesbureau Oostrandpark 30 8212 AP Lelystad The Netherlands

Drifting can be an effective way for aquatic organisms to disperse and colonise new areas. Increasing connectivity between European large rivers facilitates invasion by drifting aquatic macroinvertebrates. The present study shows that high abundances of invasive species drift in the headstream of the river Rhine. Dikerogammarus villosus and chelicorophium cur- vispinum represented up to 90% of the total of drifting macroinvertebrates. Drift activity shows seasonal and diel patterns. Most species started drifting in spring and were most abundant in the water column during the summer period. Drift activity was very low during the winter period. Diel patterns were apparent; most species, including D. villosus, drifted during the night. Drifting macroinvertebrates colonised stony substrate directly from the water column. D. villosus generally colonised the substrate at night, while higher numbers of c. curvispinum colonised the substrate during the day. It is very likely that drifting functions as a disper- sal mechanism for crustacean invaders. Once waterways are connected, these species are no longer necessarily dependent on dispersal vectors other than drift for extending their distribution range

关键词： Amphipods Invaders colonization Drift Daily rhythms Seasonal variation