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Effect of Equal Channel Angular Extrusion on the Microstructures and Properties of Two Extruded Al-Mg-Si Alloys

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Journal of Materials Science & Technology 2005年第5期21卷 623-629页

作者： g.W.Lorimer School of Materials The University of ManchesterGrosvenor StreetMl 7HS ManchesterUK

The effect of equal channel angular extrusion （ECAE） on the microstructure of two Al-Mg-Si extrusion alloys was investigated by high resolution electron backscattered diffraction （EBSD） using a field emission gun scanning electron microscope （FEg-SEM） and a transmission electron microscope （TEM）. Two contrasting alloys： a dilute alloy, based on alloy 6061 and a concentrated alloy, based on alloy 6069 were employed for this research. It has been found that prior ECAE to extrusion promotes high angle grain boundaries （HAgBs） in the extrusions, and the increase in HAgBs ratio is due to the large shear deformation involved in the process of ECAE. Tensile testing results show that a further ageing treatment strengthens the alloys after extrusion and the ECAE processed extrusions are more ductile than conventional extrusions.

关键词： Equal channel angular extrusion Electron backscattered diffraction Al-Mg-Si alloys

Numerical Analysis of Deteriorated Sub-sea Pipelines under Environmental Loads

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Chinese Journal of Mechanical Engineering 2015年第6期28卷 1163-1170页

作者： güCüYEN Engin Department of Civil Engineering Faculty of Engineering Celal Bayar University

The significant point is the bidirectional interaction technique in FSI analysis while investigating subsea corrosion effect. By this way, pipe environment is accurately modelled and fluid effects are also considered. The effect of external corrosion defects on structural behaviour of a pipeline is studied by creating a nonlinear numerical model based on the finite element method according to ABAQUS analysis program. Corrosion losses of sections are obtained from experimental results and applied to the model. Numerical model is formed by a span of sub-sea pipeline that is subjected to environmental loads. Seismic and wind-generated irregular wave loads are considered as environmental loads. Irregular wave is represented with equivalent eight regular waves via FFT. The pipe is modelled according to two different types which are non-corroded（intact） and corroded（deteriorated） to demonstrate corrosion effects on it. The visible type of corrosion in marine environment is named ‘pitting＇ corrosion, in which the material loss is locally interpenetrated over the surface. By considering this situation, the corroded and non-corroded pipes are modelled as 3D solid elements. The main point is revealing how the subsea corrosion affects the structural behaviour of pipelines on the basis of implementation of experimental results to a model structure due to changes of stresses and displacement.

关键词： offshore pipelines environmental loads corrosion numerical analysis

Catalytic dechlorination and detoxification of 1-(2-chlorophenyl) ethanol by Pd/Fe

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第5期11卷 356-362页

作者： g. Daniel SHENg College of Biological and Environmental Engineering Zhejiang University of Technology

1-(2-chlorophenyl) ethanol (CPE) is of health and environmental concern due to its toxicity and its use as an inter-mediate in pharmaceutical manufacturing. The current work deals with the catalytic reductive dechlorination and detoxification of CPE by Pd/Fe bimetal. CPE was effectively dechlorinated to 1-phenyl ethanol (PE) accompanied by the equivalent release of chloride. The extent of CPE dechlorination increased with temperature,Fe dosage and Pd loading. A decrease in solution pH increased CPE dechlorination,resulting presumably from an increase in hydrogen production. Under the specific conditions of 20 g/L Pd/Fe,0.10% Pd (w/w) and initial pH 5-6,the CPE dechlorination was completed within 145 min. The dechlorination fol-lowed a pseudo-first-order kinetics with an activation energy of 56.7 kJ/mol. The results of toxicity testing showed that CPE was very toxic to Chlorella,whereas PE showed little toxicity. The toxicity of the reaction solution declined gradually and the pro-moting effects on Chlorella intensified consequently with the dechlorination process. Thus,the reductive dechlorination of CPE to PE by Pd/Fe was a detoxification process. It may be used to effectively reduce the toxicological effects of CPE-contaminated wastewater,thereby enhancing the performance of subsequent biological processes in wastewater treatment.

关键词： 1-(2-chlorophenyl) ethanol (CPE) Pd/Fe Catalytic reductive dechlorination Detoxification 1-phenyl ethanol (PE)

Slope stability hazard management systems

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第11期8卷 1695-1711页

作者： FREDLUND Delwyn g. Department of Civil Engineering University of Saskatchewan Saskatoon SK Canada MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang University Hangzhou 310027 China

Weather-related geo-hazards are a major concern for both natural slopes and man-made slopes and embankments. government agencies and private companies are increasingly required to ensure that there is adequate protection of sloping sur- faces in order that interaction with the climate does not produce instability. Superior theoretical formulations and computer tools are now available to address engineering design issues related to the near ground surface soil-atmospheric interactions. An ex- ample is given in this paper that illustrates the consequences of not paying adequate attention to the hazards of slope stability prior to the construction of a highway in South America. On the other hand, examples are given from Hong Kong and China's Mainland where significant benefits are derived from putting in place a hazard slope stability management system. Some results from a hazard management slope stability study related to the railway system in Canada are also reported. The study took advantage of recent research on unsaturated soil behaviour and applied this information to real-time modelling of climatic conditions. The quantification of the water balance at the ground surface, and subsequent infiltration, is used as the primary tool for hazard level assessment. The suggested hazard model can be applied at either specific high risk locations or in a more general, broad-based manner over large areas. A more thorough understanding of unsaturated soil behaviour as it applies to near ground surface soils, along with the numerical computational power of the computer has made it possible for new approaches to be used in slope hazard management engineering.

关键词： Slope stability geo-hazards Highway Hazard Slope stability management system

Chemical Reduction of CO_2 to Different Products during Photo Catalytic Reaction on TiO_2 under Diverse Conditions:an Overview

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Journal of Natural gas Chemistry 2007年第3期16卷 217-226页

作者： g.R.Dey Radiation and Photochemistry Division Bhabha Atomic Research CentreTrombayMumbai 400085India

The chemical reduction of CO2 remains a challenge with respect to the reversal of the oxidative degradation of any organic materials. The conversion of CO2 into useful substances is essential in developing alternative fuels and various raw materials for different industries. This also aids in preventing the continuous rise in tropospheric temperature due to the green house effect of CO2. In this article an overview of the growth taken place so far in the field of CO2 chemical reduction is pre- sented. The discussion comprises of photochemical methods for the development of different products, viz. CO, CH3OH and CH4, through chemical reduction of CO2. This includes the use of photo catalysts, mainly TiO2, and the role of a hole scavenger （such as 2-propanol） for this purpose.

关键词： CO2 chemical reduction H2 CH4 CO TiO2 hole scavenger photolysis

Energy and momentum of rotating frames in tetrad gravity

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Chinese Physics B 2011年第10期20卷 101-111页

作者： gamal g L Nashed Mathematics Department Faculty of Science Ain Shams University

Within the framework of the tetrad formulation of general relativity theory, we compute the total energy and momentum of four rotating frames using the gravitational energy-momentum 3-form. We show how the effect of inertia always makes the total energy divergent. We use a natural regularization method to obtain physical values for the total energy of the system and show how it works on a number of explicit examples. We also show by calculation that inertia has no effect on the momentum components.

关键词： teleparallel gravity, energy-momentum WeitzenbSck connection, regularization telepar-allelism

A collaboration into research on nanoparticles (ACORN)

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Particuology 2009年第2期7卷 93-105页

作者： David g. Parker Chemistry Innovation The HeathRuncorn WA7 4QXUnited Kingdom

This paper describes the operation and outcome of one of the United Kingdom＇s largest multi-partner research activities in nanoparticles. The research covers the discovery and development of organic and inorganic crystals/nanoparticles, nanoparticle properties towards specific product applications. The research also encompassed bespoke measurement technology for nanoparticles and structure interactions. Significant research outcomes are summarised. The paper illustrates the advantages from industrially motivated research and value of collective action between a broad group of researchers in a nation.

关键词： Nanoparticles Nanoparticle manufacture Nanocrystals Nanoassembly structure Modelling

PROJECT MANAgEMENT:RECENT DEVELOPMENTS AND RESEARCH OPPORTUNITIES

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Journal of Systems Science and Systems Engineering 2012年第2期21卷 129-143页

作者： Nicholas g.HALL Department of Management Sciences Fisher College of Business The Ohio State UniversityUSA

This paper studies the business process known as project management. This process has exhibited a remarkable growth in business interest over the last 15 years, as demonstrated by a 1000% increase in membership in the Project Management Institute since 1996. This growth is largely attributable to the emergence of many new diverse business applications that can be successfully managed as projects. The new applications for project management include IT implementations, research and development, new product and service development, corporate change management, and software development. The characteristics of modem projects are typically very different from those of traditional projects such as construction and engineering, which necessitates the development of new project management techniques. We discuss these recent practical developments. The history of project management methodology is reviewed, from CPM and PERT to the influential modem directions of critical chain project management and agile methods. We identify one important application area for future methodological change as new product and service development. A list of specific research topics within project management is discussed. The conclusions suggest the existence of significant research opportunities within project management.

关键词： Project management overview recent practical developments opportunities for research

Passive electrochemical hydrogen recombiner for hydrogen safety systems:prospects

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Nuclear Science and Techniques 2023年第6期34卷 215-224页

作者： A.V.Avdeenkov D.g.Bessarabov D.g.Zaryugin All Russian Research Institute for Nuclear Power Plants Operation JSC 25 Ferganskaya Str.MoscowRussia109507 HySA Center Faculty of EngineeringNorth-West UniversityPotchefstroom2520South Africa State Atomic Energy Corporation Rosatom 24 Bolshaya Ordynka Str.MoscowRussia119017

This paper presents the concept of a passive electrochemical hydrogen recombiner(PEHR).The reaction energy of the recombination of hydrogen and oxygen is used as a source of electrical energy according to the operating principle for hydrogen fuel cells to establish forced circulation of the hydrogen mixture as an alternative to natural circulation(as is not utilized in conventional passive autocatalytic hydrogen recombiners currently used in nuclear power plants(NPPs)).The proposed concept of applying the physical operation principles of a PEHR based on a fuel cell simultaneously increases both productivity in terms of recombined hydrogen and the concentration threshold of flameless operation(the‘ignition’limit).Thus,it is possible to reliably ensure the hydrogen explosion safety of NPPs under all conditions,including beyond-design *** experimental setup was assembled to test a laboratory sample of a membrane electrode assembly(MEA)at various hydrogen concentrations near the catalytic surfaces of the electrodes,and the corresponding current–voltage characteristics were *** simplest MEA based on the Advent P1100W PBI membrane demonstrated stable performance(delivery of electrical power)over a wide range of hydrogen concentrations.

关键词： Recombiner Catalytic ignition Hydrogen explosion safety Hydrogen fuel cell Membrane electrode assembly