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Decarbonising energy: The developing international activity in hydrogen technologies and fuel cells

journal of Energy Chemistry 2020年第12期29卷 405-415页

作者： john Meurig Thomas peter p.Edwards peter j.Dobson Gari p.Owend Department of Materials Science&Metallurgy University of CambridgeCambridge CB30FSUK King Abdulaziz City for Science and Technology(KACST)-Oxford Centre of Excellence in petrochemicals and Inorganic Chemistry Laboratory University of OxfordOxford OX13QRUK The Queen’s College University of OxfordOxford OX14AWUK Annwvyn Solutions(Independent Consultant) BromleyKent BR13DWUK

Hydrogen technologies and fuel cells offer an alternative and improved solution for a decarbonised energy *** cells are electrochemical converters;transforming hydrogen (or energy sources containing hydrogen) and oxygen directly into *** hydrogen fuel cell,invented in 1839,permits the generation of electrical energy with high efficiency through a non-combustion,electrochemical process and,importantly,without the emission ofits point of ***,despite numerous efforts to exploit the obvious attractions of hydrogen technologies and hydrogen fuel cells,various challenges have been encountered,some of which are reviewed ***,however,given the exigent need to urgently seek low-carbon paths for humankind’s energy future,numerous countries are advancing the deployment of hydrogen technologies and hydrogen fuel cells not only for transport,but also as a means of the storage of excess renewable energy from,for example,wind and solar ***,hydrogen is also being blended into the natural gas supplies used in domestic heating and targeted in the decarbonisation of critical,large-scale industrial processes such as steel *** briefly review specific examples in countries such as japan,South Korea and the people’s Republic of China,as well as selected examples from Europe and North America in the utilization of hydrogen technologies and hydrogen fuel cells.

关键词： Decarbonisation Hydrogen Energy Hydrogen Economy Fuel cells Environment Sustainability

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Enhancing the high-temperature creep properties of Mo alloys via nanosized La_(2)O_(3) particle addition

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journal of Materials Science & Technology 2022年第35期130卷 53-63页

作者： p.M.Cheng C.Yang p.Zhang j.Y.Zhang H.Wang j.Kuang G.Liu j.Sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China School of Mechanical Engineering Chengdu UniversityChengdu 610106China

Molybdenum(Mo) alloys with different La_(2)O_(3)particle additions(0.6,0.9,1.5 wt.%) were prepared by powder metallurgy to investigate the effect of La_(2)O_(3)particles on microstructural evolution and creep behavior of the *** Mo,annealed at 1500℃ for 1 h,presented a fully recrystallized microstructure characterized by equiaxed *** alloys doped with La_(2)O_(3)particles(Mo-La_(2)O_(3)alloys),on the other hand,exhibited fibrous grains elongated in the rolling direction of the *** contrast to the shape of the grains,the average grain size of the alloys was found to be insensitive to the addition of La_(2)O_(3)*** La_(2)O_(3)particles with diameters ranging from 65 to 75 nm were distributed within the grain *** creep tests showed that dislocation creep was the predominant deformation mode at intermediate creep rate(10^(-7)s^(-1)-10^(-4)s^(-1)) in the present *** creep stress exponent and activation energy were found to decrease with increasing temperature,particularly within the low creep rate regime(pparent stress exponent and activation energy than pure Mo.A creep constitutive model based on the interaction between particles and dislocations was utilized to rationalize the nanoparticle-improved creep *** was demonstrated that low relaxed efficiency of dislocation line energy,which is responsible for an enhanced climb resistance of dislocations,is the major creep strengthening mechanism in the Mo-La_(2)O_(3)*** addition,the area reduction and creep fracture mode of the Mo-La_(2)O_(3)alloys were found to be a function of the creep rate and temperature,which can be explained by the effect of the two parameters on the creep and fracture mechanisms.

关键词： Mo alloys Nanosized particles Creep strength Deformation and fracture

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COMpOSITION AND RHEOLOGY OF pOLYAMIDE-6 OBTAINED BY USING BI-AND TRI-FUNCTIONAL COUpLING AGENTS

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Chinese journal of polymer Science 2013年第1期31卷 58-70页

作者： j.j.M. Slot E. van Ruymbeke p.A.M. Steeman Materials Science Centre DSM Research Department of Mathematics and Computer Science Eindhoven University of Technology

A statistical approach is developed, based on a Monte Carlo method, in order to determine the statistical composition of a polyamide-6 sample composed of caprolactam （an AB-type monomer） and of a di-acid （A2 type） or a tri- acid （A3 type） as coupling agents. For this composition, the linear theological behavior of these systems is predicted using a tube-based theory. This allows us to show that while coupling agents of type A2 can be seen as flow improver, the effect of branching agents of type A3, depending on the synthesis recipe and the conversion level, can lead either to an increase or to a decrease of the viscosity. By adding specific amount of these agents, we also show that it is possible to obtain materials with the same zero-shear viscosity but with different shear thinning behavior. Furthermore, the polydispersity of linear samples of the same average number molecular weight, Mn, is discussed in function of the amount of A2 monomers they contain. Ranging from 2 to 1.5, this difference in polydispersity is expected to have a significant influence on the processing behavior of such materials.

关键词： polyamide-6 Random branching Statistical composition Rheology Monte Carlo Tube theory.

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Accuracy details in realistic CFD modeling of an industrial centrifugal pump in direct and reverse modes

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journal of Thermal Science 2010年第6期19卷 491-499页

作者： j.C. páscoa F. j. Silva j.S. pinheiro D.j. Martins Department of Electromechanical Engineering Center for Aerospace Sciences and Technology University of Beira Interior EFAFLU Bombas e Ventiladores S.A. R. S. Brás 269 Apartado 23 4494-909 Póvoa do Varzim Portugal

Numerical computation of the flowfield inside a pump is herein used as a numerical laboratory, subject to the limitations of modeling assumptions and to experimental verification. A numerical computation of the flow inside a real industrial centrifugal pump is performed that includes a very sophisticated geometry. Conversely to other computations, in this test case no simplification of the geometry was introduced. Numerical computations are obtained using Spalart-Allmaras turbulence model. A detailed analysis of the turbulent flowstructure is performed for the design point and two off design conditions. Additional computations were performed in order to compare the numerical and experimental pump characteristics; these were obtained under normalized testing conditions. Further computations are presented for the pump working in reverse turbine mode (pAT). Detailed analyses of the flow allow a comparison of the internal flow losses when the pump is operating in direct and reverse mode. This is also useful to help in the selection of an adequate pump geometry that can work in both modes with best efficiency.

关键词： centrifugal pump impeller turbulence modeling Spalart-Allmaras pAT

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Grain Size Distribution and Interfacial Heat Transfer Coefficient during Solidification of Magnesium Alloys Using High pressure Die Casting process

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journal of Materials Science & Technology 2018年第2期34卷 324-334页

作者： p. Sharifi j. jamali K. Sadayappan j.T. Wood Western University London Ontario Canada Canmet MATERIALS Hamilton ON Canada

The objective of this study is to predict grain size and heat transfer coefficient at the metal-die interface during high pressure die casting process and solidification of the magnesium alloy AM60. Multiple runs of the commercial casting simulation package, proCASTTM, were used to model the mold filling and solidification events employing a range of interfacial heat transfer coefficient values. The simulation results were used to estimate the centerline cooling curve at various locations through the casting. The centerline cooling curves, together with the die temperature and the thermodynamic properties of the alloy, were then used as inputs to compute the solution to the Stefan problem of a moving phase boundary, thereby providing the through-thickness cooling curves at each chosen location of the casting, Finally, the local cooling rate was used to calculate the resulting grain size via previously established relationships. The effects of die temperature, filling time and heat transfer coefficient on the grain structure in skin region and core region were quantitatively characterized. It was observed that the grain size of skin region strongly depends on above three factors whereas the grain size of core region shows dependence on the interracial heat transfer coefficient and thickness of the samples. The grain size distribution from surface to center was estimated from the relationship between grain size and the predicted cooling rate. The prediction of grain size matches well with experimental results. A comparison of the predicted and experimentally determined grain size profiles enables the determination of the apparent interracial heat transfer coefficient for different locations.

关键词： High pressure die casting Grain size lnterfacial heat transfer coefficient Solidification of magnesium alloys process parameters

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Development and Electrochemical Studies of Ruthenium Based Mixed Oxide Catalyst Electrodes for Chlorine Evolution

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Chemical Research in Chinese Universities 2002年第2期18卷 133-138页

作者： L.X.Yang j.p.G.Farr Department of Chemical and processing Engineering University of Newcastle Merz CourtNewcastle upon Tyne NE17RU School of Metallurgy and Materials The University of Birmingham EdgbastonBirmingham B152TTUK

Experimental results are presented which allow comparison of the electrochemical performance of RuO 2/Ti, Ru 0 3 Sn 0 7 O 2/Ti and Ru 0 3 V 0 7 O 2/Ti catalysts prepared on a titanium substrate by thermal decomposition from respective precursors. The highest activity for chlorine evolution is observed on the Ru 0 3 V 0 7 O 2/Ti electrode, lower on Ru 0 3 Sn 0 7 O 2/Ti and least on RuO 2/Ti. Voltammograms obtained in the polarisable region are used to characterize the different electrodes. Further more an analysis of the catalytic activity and reaction kinetics of the developed electrodes in NaCl are presented.

关键词： Catalyst Cl_(2) evolution Ruthenium oxide

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A Criterion for the Change from Fast to Slow Regime of Cementite Dissolution in Fe-C-Mn Steels

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journal of Materials Science & Technology 2012年第8期28卷 728-736页

作者： M.Gouné p.Maugis j.Drillet Arcelor Mittal Research Maizières Voie RomaineBP 30320Maizières-lès-Metz 57283France ICMCB-CNRS 87 avenue du Docteur SchweitzerPessac 33609France IM2Np-UMR CNRS 6242&Aix-Marseille University Avenue Escadrille Normandie Niemen-Case 142-13397 Marseille Cedex 20France

The present study clarifies the role of Mn in cementite on the driving force of cementite dissolution and the growth of austenite. From an experimental study, the effects of manganese composition and temperature on the cementite dissolution were shown. From a theoretical analysis based on thermodynamic and kinetics considerations, a criterion for the change from fast to slow regime of cementite dissolution was proposed. This criterion is in good agreement with the experimental results. It can be easily calculated and can define the composition and temperature ranges where the cernentite dissolution is slow or fast.

关键词： phase transformation Thermodynamics Kinetics Cementite dissolution Steel

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THE EFFECT OF MEMORY TERMS IN DIFFUSION pHENOMENA

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journal of Computational Mathematics 2006年第1期24卷 91-102页

作者： A. Araújo j.A. Ferreira p. Oliveira Departamento de Matemática Universidade de Coimbra Portugal

In this paper the effect of integral memory terms in the behavior of diffusion phenomena is studied. The energy functional associated with different models is analyzed and stability inequalities are established. Approximation methods for the computation of the solution of the integro-differential equations are constructed. Numerical results are included.

关键词： Heat propagation Integro-differential equation Numerical approximation,Splitting method

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Effect of Streamwise Fences on Secondary Flows and Losses in a Twodimensional Turbine Rotor Cascade

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journal of Thermal Science 2006年第4期15卷 296-305页

作者： M.Govardhan A.Rajender j.p.Umang Thermal Turbomachines Laboratory Department of Mechanical EngineeringIndian Institute of Technology MadrasChennai 600036India

To control secondary flows, streamwise fences were attached to end wall of a linear turbine rotor cascade. The cascade had 8 blades of 400 mm long and 175 mm chord. The blades deflected the flow by 120°. The fences were made out of 0.7 mm thick brass sheet and the heights of the fences were 14 mm, 18 mm respectively. The curvature of the fences was the same as that of the blade camber line. The fences were fixed normal to the end wall and at half pitch away from the blades. The experimental program consists of total pressure, static pressure measurements at the inlet and outlet of the cascade, by using five-hole probe. In addition, static pressure on the blade suction surface and pressure surface was also obtained. Fences are effective in preventing the movement of the pressure side leg of the horseshoe vortex. Consequently the accumulation of low energy fluid on the suction surface is minimised. End wall losses are reduced by the fences due to weakening of the end wall cross flow.

关键词： Turbine cascade streamwise fences loss core lift coefficient

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Volumetric changes in the focal areas of seismic events corresponding to destress blasting

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International journal of Mining Science and Technology 2019年第4期29卷 541-547页

作者： p.Konicek j.Schreiber L.Nazarova Department of Geomechanics and Mining Research Institute of Geonics of the Czech Academy of SciencesOstrava 70800Czech Republic Laboratory of Mining Informatics Chinakal Institute of Mining of the Siberian Branch of the Russian Academy of ScienceNovosibirsk 630091Russia

The typical development of total volumetric change in the focal areas of seismic events,corresponding to destress blasting,is characterized as an explosive phase followed by an implosive phase and with alternating additional phases following on from *** a few cases,a non-typical development of volumetric change was identified,where the first phase was implosive and the second phase,*** development is mainly typical for induced seismic events recorded during mining,not for destress *** events were recorded during longwall mining in the Czech part of the Upper Silesian Coal Basin,where the destress blasting technique is used as a rockburst prevention active *** source processes in the focal areas of selected seismic events were analyzed by the seismic moment tensor inversion method,as well as by studying geomechanical rock mass conditions at the localities of the seismic *** main goal of the analysis was to attempt to identify the reasons for non-typical development of volumetric changes in these *** changes were analyzed for seismic events with energy greater than 104 j,recorded in the period of time from 1993 to 2009(1109 events).80%(891)of the recorded seismic events were induced seismic events that were registered during longwall mining and 20%(218)corresponded to destress blasting *** shows that the main reason for the non-typical development of volumetric changes in the focal areas of seismic events is an association with destress blasting in the rock mass,which is very close to rock mass *** detonation of explosives in boreholes,which would dominate the first phase of volumetric changes,probably obscured stress release in the rock mass,as manifested in the first implosion phase of the volumetric changes in this case.

关键词： Destress blasting Seismic event Volumetric changes Stress release

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