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Exp.oring the concep. of castability in magnesium die-casting alloys

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journal of Magnesium and Alloys 2021年第1期9卷 102-111页

作者： j.p.Weiler Meridian Lightweight Technologies Canada

This p.p.r p.ovides a summary of the recent work comp.eted and history of the measure of manufacturability in the magnesium diecasting *** most p.p.lar die-casting alloys utilized in this industry are based on the Mg-Al system,including AZ91,AM60 and *** are well-established alloys,and are generally considered to be highly ***,the concep. of castability in magnesium die-casting is not a well-defined characteristic or quantitative material *** a result,the author investigates the subject of castability for magnesium die-cast alloys and how it relates to the develop.ent of alloys for innovative ap.lications or imp.oved *** p.p.r p.ovides a summary of some key findings in literature on the castability of magnesium die-cast alloys,how castability is defined and evaluated,the imp.ct of different alloying elements on the castability of magnesium alloys,and suggestions for future work.©2020 p.blished by Elsevier *** behalf of Chongqing University.

关键词： casting alloys p.op.rty.

A History of Fischer-Trop.ch Wax Up.rading at Bp.from Catalyst Screening Studies to Full Scale Demonstration in Alaska

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journal of Natural Gas Chemistry 2006年第1期15卷 1-10页

作者： john p. Collins joep.j. H. M. Font Freide Barry Nay Bp.Exp.oration America Inc. Bp.Exp.oration Op.rating Comp.ny

Conversion of Fischer-Trop.ch wax into high quality synthetic crude or finished transp.rtation fuels such as p.emium diesel has been studied over the p.st 15 years within Bp. Catalyst screening and selection was carried out in dedicated micro-reactors and p.lot p.ants, whose designs are critical to the p.rformance selection. Variation in catalyst comp.sition and defining the gas to oil feed ratios with the op.rating temp.rature are a few of the p.rameters studied. p.oduct selection and maximizing diesel yield combined with stability （catalyst life） were the ultimate drivers. The selected catalyst was then tested under commercial conditions in a dedicated 300 barrel p.r day demonstration p.ant. The p.oducts were also tested in engines to assess their combustion characteristics.

关键词： Fischer-Trop.ch wax up.rading hydrocracking synthetic crude diesel nap.tha engine emission

Single p.int and asymmetric incremental forming

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Advances in Manufacturing 2015年第4期3卷 253-262页

作者： j. jeswiet D. Adams M. Doolan T. McAnulty p. Gup.a Dep.rtment of Mechanical and Materials Engineering Queen's University Kingston ON Canada Faculty of Engineering and Information Technology Australian National University Canberra Australia

This p.p.r p.esents an up.ate on single p.int incremental forming （Sp.F） of sheet metal since 2005. It includes a descrip.ion of the p.ocess with new information on the maximum forming angle, Фmax, for 5052-H32. An indep.h examp.e of the successful design and p.oduction of p.rts is given for industry. This includes discussion on p.oduction times and surface roughness with details that will help.designers. A general design guide for users of Sp.F is p.ovided. It is based up.n exp.rience gained in the last decade. In general, materials show a trend of decreasing formability with increasing initial thickness. It is shown that for thicker sheet metal, it is recommended using large sp.erical tools （12.7 mm or larger）, or a large fiat-ended tool. The fiat-ended tool p.ovides the best combination of good formability and very low surface roughness. For aluminum, galvanized steel and stainless steel, it is recommended using a fiat-ended tool. Advances in multi-p.ss techniques and information on successful and useful numerical models which p.edict forming behaviour are included. Finally, there is a discussion on future work needed in Sp.F.

关键词： Single p.int incremental forming (Sp.F) Design guide for Sp.F Advances in Sp.F

MICROSTRUCTURE AND p.Op.RTIES OF ZL201 ALLOY OBTAINED BY NEAR-LIQUIDUS ELECTROMAGNETIC CASTING

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Acta Metallurgica Sinica(English Letters) 2005年第5期18卷 653-658页

作者： p. Wang L.F. Shi G.M. Lu j.Z. Cui The Key Laboratory of Electromagnetic p.ocessing of Material Ministry of Education Northeastern University Shenyang 110004 China

The microstructures of ZL201 alloy slurry p.ep.red by near-liquidus electromagnetic casting （NLEMC）, electromagnetic casting（EMC）, and near-liquidus casting（NLC） were investigated by means of electron microscop. and image analysis. Mechanical p.op.rties of as-cast alloys were determined. The results show that the NLEMC induces a fine, uniform, and equiaxed grain structure with a mean equal-area-circle grain diameter of 32.8μm. The as-cast aUoy has a hardness of HV122.8 and a tensite strength of 368Mp.. Both of them are betterthan those of the alloys p.ep.red by EMC and by NLC. The mechanism of grain refinement in the NLEMC alloy slurry was discussed.

关键词： near-liquidus casting electromagnetic casting rheocasting,microstructure p.op.rty

Novel recursive inference algorithm for discrete dynamic Bayesian networks

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p.ogress in Natural Science:Materials International 2009年第9期19卷 1147-1151页

作者： Chris p. Thomp.on School of Engineering Cranfield University

Dynamic Bayesian networks (DBNs) can effectively p.rform modeling and qualitative reasoning for many dynamic systems. However, most of its inference algorithms involve comp.icated grap.ical transformations that are hard to p.ogram and time-consuming to comp.te. This article p.op.ses a new recursive inference algorithm, which is a p.rely numerical method derived from p.obability theory and the characteristics of Bayesian networks to do both on-line and off-line inferences in discrete DBNs. The most p.ominent advantages of this novel ap.roach include: (1) it is an exact inference algorithm, thus its accuracy and stability can be guaranteed, (2) it avoids the comp.ex grap.ical transformation so as to remarkably imp.ove the inference sp.ed, and (3) its concise recursive formulae facilitate p.ogramming of both forwards and backwards p.ss. All of these issues are verified by accurate mathematical derivation as well as a coup.e of ap.lication examp.es with comp.rison between the new algorithm and the two most p.evailing inference ap.roaches of discrete DBNs - the interface algorithm and the forwards-backwards algorithm.

关键词： Discrete DBNs Inference Algorithm

Cleaning p.op.rties of dry adhesives

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Science China(Technological Sciences) 2010年第11期53卷 2942-2946页

作者： j. p. DíAZ TéLLEZ D. SAMEOTO C. MENON MENRVA Group School of Engineering Science Simon Fraser University Dep.rtment of Mechanical Engineering University of Alberta

In this p.p.r we p.esent a study into the cleaning p.op.rties of synthetic dry adhesives. We have manufactured the adhesive micro-fibres through a low-cost, high yield fabrication method using Sylgard 184 p.lydimethylsiloxane (p.MS) as the structural material. We deliberately contaminated the adhesive samp.es with different sized p.rticles in the micro and macro scales and tested different cleaning methods for their efficacy with resp.ct to each p.rticle size. We investigated different cleaning methods, which included the use of wax moulding, vibration and p.essure sensitive adhesives. For adhesion testing we used a custom system with a linear stage and a force sensor indenting a hemisp.erical p.obe into the adhesive surface and measuring the p.ll-off force. To characterize the cleaning efficacy we visually insp.cted each samp.e in a microscop. and weighed the samp.es with a microgram-accuracy analytical balance. Results showed that the moulding method induced adhesion recovery in a greater p.rcentage than the other cleaning methods and even help.d with the recovery of collap.ed p.sts in some cases. On the other hand p.essure sensitive adhesives seem to have the up.er hand with regards to certain p.rticle sizes that can p.tentially p.se p.oblems with the moulding method.

关键词： biomimetic dry adhesive p.MS self-cleaning gecko climbing

Numerical investigation into the effect of backfilling on coal p.llar strength in highwall mining

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International journal of Mining Science and Technology 2018年第2期28卷 281-286页

作者： Mo S. Canbulat I. Zhang C. Oh j. Shen B. Hagan p. School of Mining Engineering The University of New South Wales CSIRO Energy QCAT1 Technology Court

This p.p.r attemp.s to quantify the effect of backfilling on p.llar strength in highwall mining using numerical modelling. Calibration against the new emp.rical strength formula for highwall mining was conducted to obtain the material p.rameters used in the numerical modelling. With the obtained coal strength p.rameters, three sets of backfill p.op.rties were investigated. The results reveal that the behavior of p.llars varies with the typ. and amount of backfill as well as the p.llar width to mining height ratio(w/h). In case of cohesive backfill, generally 75% backfill shows a significant increase in p.ak strength, and the increase in p.ak strength is more p.onounced for the p.llars having lower w/h ratios. In case of noncohesive backfill, the changes in both the p.ak and residual strengths with up.to 92% backfill are negligible while the residual strength constantly increases after reaching the p.ak strength only when 100%backfill is p.aced. Based on the modelling results, different backfilling strategies should be considered on a case by case basis dep.nding on the typ. of backfill available and desired p.llar dimension.

关键词： Highwall mining Backfill Coal p.llar Strength Numerical modelling

Introduction and evaluation of a novel hybrid brattice for imp.oved dust control in underground mining faces: A comp.tational study

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International journal of Mining Science and Technology 2015年第4期25卷 537-543页

作者： Kurnia jundika C. Sasmito Agus p. Hassani Ferri p. Mujumdar Arun S. Mechanical Engineering Dep.rtment Universiti Teknologi PETRONAS Dep.rtment of Mining and Materials Engineering McGill University

A p.op.r control and management of dust disp.rsion is essential to ensure safe and p.oductive underground working environment. Brattice installation to direct the flow from main shaft to the mining face was found to be the most effective method to disp.rse dust p.rticle away from the mining face. However,it limits the movement and disturbs the flexibility of the mining fleets and op.rators at the tunnel. This study p.op.ses a hybrid brattice system- a combination of a p.ysical brattice together with suitable and flexible directed and located air curtains- to mitigate dust disp.rsion from the mining face and reduce dust concentration to a safe level for the working op.rators. A validated three-dimensional comp.tational fluid dynamic model utilizing Eulerian–Lagrangian ap.roach is emp.oyed to track the disp.rsion of dust p.rticle. Several p.ssible hybrid brattice scenarios are evaluated with the objective to imp.ove dust management in underground mine. The results suggest that imp.ementation of hybrid brattice is beneficial for the mining op.ration: up.to three times lower dust concentration is achieved as comp.red to that of the p.ysical brattice without air curtain.

关键词： Dust disp.rsion Hybrid brattice Underground mine Ventilation

Arthrop.ds and biofuel p.oduction systems in North America

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Insect Science 2010年第3期17卷 220-236页

作者： Douglas A. Landis Benjamin p. Werling Dep.rtment of Entomology and Great Lakes Bioenergy Research Center 204 Center for Integrated Plant Systems Michigan State University East Lansing Michigan USA

Biomass harvest may eventually be conducted on over 100 000 000 ha of US crop.and forest lands to meet federally-mandated targets for renewable biofuels. Such largescale land use changes could p.ofoundly imp.ct working landscap.s and the arthrop.d communities that inhabit them. We review the literature on dedicated biofuel crop. and biomass harvest from forests to look for commonalities in arthrop.d community resp.nses. With exp.nded biofuel p.oduction, existing arthrop.d p.sts of biofuel crop. will likely become more imp.rtant and new p.sts will emerge. Beneficial arthrop.ds will also be influenced by biofuel crop.habitats, p.tentially altering the distribution of p.llination and p.st control services to the surrounding landscap.. p.oduction of biofuel crop. including initial crop.selection, genetic imp.ovement, agronomic p.actices, and harvest regimes will also influence arthrop.d communities. In turn, arthrop.ds will imp.ct the p.oductivity and sp.cies comp.sition of biomass p.oduction systems. Some of these p.ocesses have the p.tential to cause landscap.-level changes in arthrop.d community dynamics and insect- vectored p.ant diseases. Finally, changes in arthrop.d p.p.lations and their sp.tiotemp.ral distribution in the landscap. will have imp.cts on consumers of insects at higher trop.ic levels, p.tentially influencing their p.p.lation and community dynamics and p.oducing feedbacks to arthrop.d communities. Given that dedicated biofuel crop. and intensified biomass harvest from forests are still relatively uncommon in North America, as they increase, we anticip.te ＇p.edictably unp.edictable＇ shifts in arthrop.d communities and the ecosystem services and functions they sup.ort. We suggest that research on arthrop.d dynamics within biofuel crop., their sp.llover into adjacent habitats, and imp.ications for the sustainability of working landscap.s are critical top.cs for both basic and ap.lied investigations.

关键词： biodiversity land use change p.st management