循环型社会的生态环境材料

生态环境材料的概念已被广泛接受,研究的生态环境材料得到了实际应用.文章就近年来源头无毒无害的材料及制品、节能环保的材料生产和使用技术、废弃材料的资源循环利用技术、天然资源材料、生物降解材料,以及消除污染和修复环境的环境工程材料等领域的发展进行了概要介绍.     

先进材料设计的若干前瞻性思考——兼评阻碍新材料商品化进程的种种因素

在资源和环境恶化的情况下,材料科学家和化学家从可持续发展的角度提出生态环境材料和绿色化学化工及环境友好材料的概念。材料是人类社会发展和技术进步及现代文明的物质基础和先导,为此现代先进材料设计应从根本上预测其环境的协调性,简要介绍现代先进材料设计的若干前瞻性思考及绿色化学－化工概念。从宏观和微观材料学角度讨论发展先进材料与可持续发展的关系,并兼评当前阻碍新材料商业化进程的种种因素。     

A machine learning approach to optimise the usage of recycled material in a remanufacturing environment

Remanufacturing has acquired importance in recent years because of the increasing environmental concerns of manufacturing processes that deplete the Earth's resources. Some examples of remanufactured products are automobile parts, furniture, photocopiers, and computer printers. In a remanufacturing setup, raw materials are drawn from two sources: (i) ‘cores’, which are obtained from recycled products, and (ii) ‘non-recycled’ or unused materials, which are produced from minerals freshly mined from the earth. An important decision for the manager is to select material optimally from these two sources. Using cores has environmental benefits, and because they are cheap, they reduce manufacturing costs. However, their use generally increases the production time, because of the additional pre-processing usually needed, which can negatively impact service levels. When the supply of finished products is running low, to satisfy service levels, it makes sense to use unused material. This research focuses on identifying an optimal strategy of switching between the two sources of material. A reinforcement learning algorithm is used to solve the switching problem. The switching algorithm produced encouraging results, showing up to 65% cost improvements over a policy that uses only unused materials.     

The ‘IMC rings’ growth mechanism in Sn–Ag–Cu solder ball and NiAu-plated BGA ball pad

Due to environmental pollution concerns, the law says the lead (Pb) inside electronics devices must be eliminated. Lots of lead-free materials have been introduced and been used for electronic products and Sn–Ag–Cu (SAC) is one of most popular lead-free representatives and has been used in high-volume production. The most popular IC packages, BGA packages which have higher I/O counts, and better thermal and electrical performance than lead-frame type packages, use solder balls of SAC for lead-free applications to connect with printed circuit boards. A particular phenomenon, so-called ‘IMC rings’, is only observed on BGA solder ball pad surfaces after the SAC solder balls are mounted on BGA ball pads which are plated with NiAu. It has not been found in either eutectic solder or Sn–Ag solder welding on plated NiAu pads. No significant evidence exists to show that ‘IMC rings’ degrade the strength of solder joints or cause earlier failures in mechanical tests. ‘IMC rings’ appear to be an inevitable outcome after the SAC is soldered onto a plated NiAu ball pad. This study is to find the growth mechanism of ‘IMC rings’ on the ball pad which is created between SAC ball and plated NiAu pad during solder ball temperature reflow. The design of the experiment and data have been discussed.     

Advances in nature-guided materials processing

The center of excellence (COE) titled ‘The Creation of Nature-Guided Materials Processing’ has been established in Nagoya University as the 21st Century COE Program supported by Ministry of Education, Culture, Sports, Science and Technology. In the Nature COE, various activities on the education and research are being performed through learning the laws of nature, namely, methods of attaining ‘appearance of the maximum function under the minimum substance and energy consumption’, which the nature and living organisms have acquired through their evolution in long period. Together with such educational programs for PhD students as research incentive, oversea training, and external evaluation programs, an ‘Open-Cluster Program’ was originated for promoting researches proposed by research groups consisting of young researchers in and out of the university and also for fostering them.

The researches are being advanced on materials used for living bodies, mimicking structures which nature or living bodies are forming, and producing materials by mimicking processes to form the structures observed in the nature or the living bodies. In this COE, these researches are conducted by four groups to extend the processes observed in the natural world to a new type of processing, that is, thoroughly examined and rationalized by plunging a scalpel of engineering and to establish a new academic field of materials science and engineering.     

New functionalities in abundant element oxides: ubiquitous element strategy

Abstract

While most ceramics are composed of ubiquitous elements (the ten most abundant elements within the Earth's crust), many advanced materials are based on rare elements. A ‘rare-element crisis’ is approaching owing to the imbalance between the limited supply of rare elements and the increasing demand. Therefore, we propose a ‘ubiquitous element strategy’ for materials research, which aims to apply abundant elements in a variety of innovative applications. Creation of innovative oxide materials and devices based on conventional ceramics is one specific challenge. This review describes the concept of ubiquitous element strategy and gives some highlights of our recent research on the synthesis of electronic, thermionic and structural materials using ubiquitous elements.     

The influence of international collaboration on the impact of research results

There is an ongoing discussion on the influence of international collaboration on impact as measured by citation-based indicators. Collaboration generally involves more authors than ‘no collaboration’ work and it is obvious that the phenomenon of self-citation will be stronger (there are more authors to cite themselves). Thus it can be seen as an important ‘amplifier’ of measured impact. Although this effect is certainly possible and already demonstrated recently, it should not be considered as the only or even major explanation of higher impact in the comparison between ‘no collaboration’ and international collaboration. Using data of an extensive bibliometric study of astronomical research in the Netherlands, we prove that higher rates of self-citation in international collaboration do not play any significant role as ‘impact amplifier’. The central point is that proper impact measurement must involve corrections for self-citations.     

Effectiveness of environmental offsets in environmental impact assessment: practitioner perspectives from Western Australia

Environmental offsets are positive mitigation measures implemented during environmental impact assessment (EIA) approvals to compensate for unavoidable negative environmental actions. Through interviews with 29 practitioners experienced with offsets, this study investigated the level of support for environmental offsets in Western Australia, implementation of the mitigation sequence and achievement of ‘net environmental gain’ and ‘like for like’ in practice. In-principle support for the use of offsets was almost unanimous. However, the practical workability of ‘like for like’ was questioned along with claims that offsets failed to deliver net benefits. Greater guidance and follow-up will be necessary if practice is to live up to expectation.     

Antecedents of implementation success in closed-loop supply chain: an empirical investigation

Implementation of closed-loop supply chain (CLSC) has gained increased consideration in the last few years owing to an increase in environmental concerns, product returns and scarcity of natural resources. It aids in improving environmental, economic and social performances. The purpose of this study is to examine the impact of CLSC critical success factors (CSFs) on performance outcomes. Firstly, CSFs and performance outcomes are extracted by conducting exploratory factor analysis using SPSS software. Then, the relationships between CLSC CSFs and performance outcomes are empirically tested by Partial Least Squares-Structural Equation Modelling (PLS-SEM) approach, using the data collected from 138 professionals working in remanufacturing, refurbishing and recycling operations in North American manufacturing organisations. Empirical analysis demonstrates that CSFs, ‘environmental concerns’, ‘sustainable production’ and ‘product design and collection’ have a significant positive effect on environmental performance. Results also validate the significant positive effect of CSFs, ‘demand and inventory management’ and ‘raw material prices’ on economic performance. In our knowledge, this is the first study that examines the impact of CLSC CSFs on performance outcomes. The results provide managers in manufacturing organisations with insights on most important CSFs that improve performance.     

Smoothed finite element method for topology optimization involving incompressible materials

It is well known that the finite element method (FEM) suffers severely from the volumetric locking problem for incompressible materials in topology optimization owing to its numerical ‘overly stiff’ property. In this article, two typical smoothed FEMs with a certain softened effect, namely the node-based smoothed finite element method (NS-FEM) and the cell-based smoothed finite element method, are formulated to model the compressible and incompressible materials for topology optimization. Numerical examples have demonstrated that the NS-FEM with an ‘overly soft’ property is fairly effective in tackling the volumetric locking problem in topology optimization when both compressible and incompressible materials are involved.     

The role of editorial material in bibliometric research performance assessments

In this study, the possibilities to extend the basis for research performance exercises with editorial material are explored. While this document type has been traditionally not considered as an important type of scientific communication in research performance assessment procedures, there is a perception from researchers that editorial materials should be considered as relevant document types as important sources for the dissemination of scientific knowledge. In a number of these cases, some of the mentioned editorial materials are actually ‘highly cited’. This lead to a thorough scrutiny of editorials or editorial material over the period 1992–2001, for all citation indexes of Thomson Scientific. The relevance of editorial materials through three quantitative bibliometric characteristics of scientific publications, namely page length, number of references, and the number of received citations, are thoroughly analyzed.     

Tapping into hidden potential

University departments are going to great lengths to convince potential new recruits that materials science and engineering is for them. In addition to the traditional showcase ‘Open Day’ for pre-university students, outreach staff are facilitating hands-on workshops, problem-solving seminars, and research ‘tasters’ for a far wider audience. High school students are shown how materials science spans traditional subject divides, while teachers receive tips on how to integrate materials-oriented examples into the curriculum. The idea is to show would-be electrical engineers, doctors, and chemists that a degree in materials science could lead to an equally exciting and fulfilling career developing optical materials, biomedical implants, or sensor technology.As the academic year begins, students enrolling at universities worldwide have a treat in store. There is a course on offer that could explain how to cut the cost of street lighting, improve the mobility of an aging population, reduce the amount of waste sent to landfill, speedup electronic communication, and detect the first signs of a biological terrorist attack. No surprises, then, for guessing that this course is materials science and engineering. But teenagers versed in the language of physics, chemistry, biology, and engineering may not have made the connection. And there in lies the root of a possible recruitment problem.     

Closed-loop supply chains of reusable articles: a typology grounded on case studies

Reuse practices contribute to the environmental and economical sustainability of production and distribution systems. Surprisingly, reuse closed-loop supply chains (CLSC) have not been widely researched for the moment. In this paper, we explore the scientific literature on reuse and we propose a definition for reusable articles and a typology integrating different categories of articles (transportation items, packaging materials, tools) under the term ‘reusable articles’. Our definition shows how reusable articles are different from other types of recovery, such as remanufacturing or recycling. We also point out specific research needs for those articles. We have based our results on a set of case studies developed in real industrial settings, which have also been contrasted with cases available in the existing literature.     

Influence of energy density on metallurgy and properties in metal additive manufacturing

Fabricating metallic components for highly specialised industries such as automotive and aerospace has become the main focus of additive manufacturing (AM) due to its many advantages over traditional processes. This review initially outlines current AM techniques for processing metallic components, particularly on ‘powder bed fusion’ and ‘directed energy deposition’ categories. Various solidification and metallurgical aspects, microstructure and properties of fabricated parts are described in subsequent sections. In addition, the influence of energy density on metallurgy, microstructure and mechanical properties is addressed. The need to establish processing maps for various materials and techniques, and the challenges currently faced in metal AM are then highlighted. The final section provides an outlook for the future of research in AM of metals.     

Comparative experimental study of sand and binder for flowability and casting mold quality

A good sand mold is an indispensable prerequisite to obtaining a good metal casting. Although sand casting is one of the oldest metal forming technique known to humans, it still has a lot to discover. In a bid to meet the ever-growing demand for quality, economics and increasing environmental restrictions, research is still ongoing to optimize for example the process of making the sand mold. This paper presents a comparative study of six different foundry sands for flowability using simple inexpensive apparatus and some quality parameters achieved by these sands when used with three different types of binder, two organic and one inorganic. The study aims to facilitate the choice of mold materials with a more extensive outlook into their characteristics through a serious of sand and mold tests. A good comparison of already existing materials provides a good reference point when novel materials are investigated. All the sands exhibited ‘good’ flow property according to the simple flowability tests done. However, not the same consensus for flowability rank is reached by all the flow tests. The mold quality tests reveal the strength, loss on ignition and permeability values achieved with each of the binder and sand combination which can also be used in mold material selection.     

Ignition of flammable gases and vapours by friction between footwear and flooring materials

For pedestrian locomotion, friction between footwear and flooring materials is necessary. What is not, perhaps, realised is that friction between two surfaces can produce temperatures approaching the lower of the melting points of the two materials. In circumstances where material is transferred from one surface to the other, temperatures near the higher melting point may be realised. Thus, with many everyday materials, temperatures approaching 1500° C are possible.Sparks are pieces of the hot surfaces ejected into the atmosphere. Those from materials that do not burn or oxidise in the atmosphere begin to cool as soon as they are formed. Certain materials, however, oxidise rapidly and their sparks can attain temperatures approaching 3000° C.Such hot surfaces or sparks produced in the vicinity of flammable gases or vapours can lead to fires and explosions.Tests of ‘hobnails’, tungsten carbide studs and ‘non-sparking’ materials, using a machine that can simulate a glancing kick, in flammable mixtures are described. Other materials that are used for footwear and flooring are discussed from the point of view of frictional ignition of gases and vapours.     

PVC thermoformed containers for food packaging: establishment of a rapid extraction test for overall migration limit compliance testing

In order to demonstrate compliance with the overall migration limit given in amended EC Directive 90/128/EEC, overall migration tests are usually performed on the finished food packaging with food stimulants. For packaging converters, in particular, who thermoform a wide range of containers from an extruded sheet, the cost of testing for compliance can be prohibitive. However, the Directive also allows compliance to be demonstrated by use of a ‘more severe test’. In this study a ‘more severe test’ has been developed for PVC and VC/VA co-polymer materials involving extraction with methanol or a methanol/water mixture and evaporation to dryness. This procedure has been optimised so that it is simple and rapid to perform and gives slightly higher results for the extruded sheet compared to overall migration tests conducted with fatty and aqueous food simulants. Results are presented demonstrating the rapid extraction test to be a ‘more severe test’ and that it could be used by converters in conjunction with good manufacturing practice (GMP) to demonstrate compliance with the overall migration limit in a cost-effective way. © 1997 John Wiley & Sons, Ltd.     

The innovation and performance effects of well-designed environmental regulation: evidence from Sweden

This paper provides novel empirical insights into the Porter hypothesis (PH) and its dynamic nature. The PH posits that well-designed environmental regulations induce eco-innovations at polluting firms that improve both their environmental and business performance via ‘innovation offsets.’ We conduct an econometric test of this proposition, using Swedish pulp and paper plants as empirical application. Swedish environmental regulation of polluting industries provides an interesting case because it has been praised, due to containing elements of ‘well-designed’ regulations, for being conducive to accomplishing the ‘win-win’ situation of mutual environmental and economic benefits. The empirical results indicate that flexible and dynamic command-and-control regulation and economic incentive instruments have induced innovation offsets through improved energy efficiency. Our study bears important implications: empirical tests of the PH that do not account for its dynamic nature, and that do not measure ‘well-designed’ regulations, might provide misleading conclusions as to its validity.     

Research opportunities in superconductivity

Opportunities for research in the field of superconductivity are identifield in this report of a ‘Workshop on problems in superconductivity’ held at Copper Mountain, Colorado, August 22–23, 1983. Key problems in superconductivity, high payoff areas of research, barriers to progress, and the need for new facilities are outlined in the three areas of basic physics, materials, and devices.     

An overview of smart technology

In recent years there has been a seemingly ever-increasing use of the synonymous adjectives ‘smart’ and ‘intelligent’ to describe a diverse range of materials, structures, systems and technologies.^1-4 The origin of this terminology can be dated to the early 1980s when researchers working mainly in the US, and funded predominantly from defence budgets, began to examine the potential of combining advanced materials and sensors with powerful and compact computers to produce futuristic systems able to monitor their operating environment in real time and respond appropriately. Public awareness of this technology was given an enormous boost by the prominence given to use of ‘smart’ munitions during the Gulf war. Various articles appearing in popular science journals^5–7 and broadsheet newspapers in the months following the successful conclusion of this conflict served to maintain interest and it became fashionable to examine the use of ‘smart’ technology in industrial applications far removed from those originally envisaged in aerospace and defence. Various dedicated university research groups were formed at around this time (among the first in the UK being the Smart Structures Research Institute at Strathclyde University), often bringing together academics who had been working on ‘smart’ technologies for several years without realising it! Over the last five years researchers working in most of the major industrial sectors have given at least some thought to how they might apply ‘smart’ technology, important areas being in transport, building, civil infrastructure, biomedicine, sport and leisure, power generation and oil, gas and petrochemical. Packaging has not been left out of this process, with the prospects for ‘intelligent packaging’ being assessed most notably by CEST and Pira International in a report prepared in 1992 under DTI funding.⁸ Interest in ‘smart’ packaging has been sustained over the four years since this pioneering study, with the focus of attention gradually shifting from abstract conjecture to practical application. Notwithstanding the attention now being devoted to all things ‘smart’, the underlying concepts are still only poorly understood in many quarters and the word must warrant some sort of prize for the proportion of times that it is inaccurately applied. This paper presents a systematic definition of ‘smart’ technology and goes on to review very briefly some of the major advances being made under this technological umbrella. The UK's Defence Research Agency (DRA), like its American counterparts, has been active in ‘smart’ technology from its earliest days and has, for obvious reasons, concentrated mainly on aerospace and defence applications. However, with the launch in April 1994 of the DRA's Structural Materials Centre (SMC), committed explicitly to promoting wealth creation via the dual (i.e. military and civil) use of technology, there has been a conscious effort to identify wider opportunities for the exploitation of the contributing ‘smart’ technologies. Some ideas relevant to packaging which are currently being developed in conjunction with the DRA's Packaging Authority are outlined, together with an invitation for interested companies to participate in various DRA-led joint development programmes. © 1997 John Wiley & Sons, Ltd.