An experimental investigation into micro ball end-milling of silicon

Silicon is a representative operational material for semiconductor and micro-electronics. In certain MEMS applications, it is required to fabricate three dimensional channels and complex pattern on silicon substrate. Such features are typically fabricated by photolithography and chemical etching. These processes have low productivity and have certain other limitations. Therefore, a viable switch-over from non-traditional fabrication processes to traditional machining is highly desired for improved productivity in high-mix low-volume production. However, machining of silicon by traditional process is extremely difficult due to its high brittleness. Even very small forces produced during machining can cause brittle fracture on silicon surface resulting in deteriorated surface quality. The fundamental principle in machining of a brittle material such as silicon is to achieve material removal through plastic deformation rather than crack propagation. This paper presents the experimental results of ductile-mode machining of silicon by micro ball end-milling. The workpiece surface was inclined to the rotational axes of the cutter to improve the surface finish. It was established experimentally that 15-μm deep, fracture-free slots can be machined on silicon wafer by micro ball end-milling if the feed rate is below a certain threshold. The influence of several machining parameters on the roughness of machined-surface was also investigated. Cubic boron nitride (CBN) is presented as much economical alternative tool-material to single-crystal diamond for machining silicon in ductile-mode.     

The Impact-Likelihood Matrix: A policy tool for behaviour prioritisation

The proliferation of applied behaviour change science over the past decade has provided new ways of thinking about policy making. Policy makers now have a range of frameworks and methods to assist in formulating change for social and environmental benefits. However, the development of strategies for the identification and prioritisation of target behaviours has been less forthcoming. This paper outlines a tool to assist in behaviour selection. Behaviours are assessed for their potential impact on addressing a specific issue, the likelihood of adoption by the target audience and existing participation levels within the target audience. Each of these characteristics is scored, allowing behaviours to be mapped onto a meaningful, visual, matrix for prioritisation. Additional data on behaviour type and the key perceived barriers to participation in each behaviour are layered onto the matrix to provide direction for intervention design. An application of the prioritisation matrix is presented within an environmental context through a case study of water demand management behaviours for domestic consumers in Australia. The prioritisation matrix could provide a decision-making tool for policy makers to assist in the selection of target behaviours to address complex issues.     

冲压模CAE技术及软件选型方法

综述了国内外常用冲压模具CAE分析软件的内容和种类 ,从实用角度讨论了CAE系统应用中诸如规划、软件选型、人员培训、应用推广等问题 ,对其选型和实施方法作了重点介绍     

Development of collision risk indicators for autonomous subsea inspection maintenance and repair

The objective of this article is to present a method for developing collision risk indicators applicable for autonomous remotely operated vehicles (AROVs), which are essential for promoting situation awareness in decisions support systems. Three suitable risk based collision indicators are suggested for AROVs namely, time to collision, mean time to collision and mean impact energy. The proposed indicators are classified into different thresholds; low, intermediate and high. An AROV flight path is simulated to gather input data to calculate the proposed indicators and three collision targets are established, i.e., subsea structure, seabed and a cooperating AROV. The proposed indicator development method together with the case study show a proof-of-concept that the combination of mean time to collision and mean impact energy indicators can identify risk prone waypoints in the AROV path. The method results in an overall risk picture for a given AROV path. The results may provide useful input in replanning of mission paths and for implementation of risk reducing measures. Even though the method focuses on collision risk, it can be used for other accident scenarios for AROVs.     

Major accident management in the process industry: An expert tool called CESMA for intelligent allocation of prevention investments

A tool (called CESMA) was developed to carry out cost–benefit analyses and cost-effectiveness analyses of prevention investments for avoiding major accidents. A wide variety of parameters necessary to calculate both the costs of the considered preventive measures and the benefits related with the avoidance of accidents were identified in the research. The benefits are determined by estimating the difference in (hypothetical) major accident costs without and with the implementation of a preventive measure. As many relevant costs and benefits as possible were included into the tool, based on literature and expert opinion, in order to be able to deliver an all-embracing cost–benefit analysis and cost-effectiveness analysis to assist in the investment decision process. Because major accidents are related to extremely low frequencies, the tool takes the uncertainty of the unwanted occurrence of a major accident into account through the usage of a so-called ‘disproportion factor’. Compared with existing software, the CESMA tool is innovative by striving for an as-accurate-as-possible picture of costs and benefits of major accident prevention, and taking the uncertainties accompanying disastrous events into consideration. Furthermore, an illustrative example of CESMA is presented in the paper.     

基于CSGD的排放清单处理工具研究

CSGD（crowd sourcing geographic data,众源地理数据）是通过互联网向大众或相关机构提供的一种开放地理空间数据,具有易获取、时效性好、准确性高等特点,在排放清单时空分配方面具有应用潜力.然而,现有排放清单处理工具不支持CSGD数据直接输入且难以满足排放清单空间分配和空气质量模式所需清单格式,因此,亟待开发一套可以拓展该类数据在排放清单领域应用的工具.以CSGD中的POI（城市设施兴趣点）数据为主要研究对象,基于QGIS平台、C++语言及Python语言,开发了在Windows系统下的ISAT（inventory spatial allocate tool,排放清单空间分配工具）工具及在Windows或Linux系统下的ISAT.M工具.结果表明:ISAT工具以POI数据为基础制作出的空间分配结果与排放源排放强度的空间分布特征的一致性较好;ISAT.M工具输出的inline清单可以作为CMAQ空气质量模式及其DDM敏感性分析模块的输入文件并开展模拟,通过与SMOKE模型的关闭源法模拟结果对比发现,二者在数据及空间分布上呈较好的一致性.研究显示,CSGD数据应用于排放清单空间分配可较好地反映排放源空间分布特征,同时由于此类数据存在信息冗杂、近郊区数据缺失等问题,在应用过程中应注意数据清洗及数据种类的选取工作.      

Footprints for Sustainability: The Next Steps

The concept of an ecological footprint is based on the understanding that every individual human appropriates a share of the productive and assimilative capacity of the biosphere. An ecological footprint corresponds to this exclusive biologically productive area that a defined population uses for all its resource requirements and wastes, and is expressed in terms of bioproductive space, with world-average productivity. Humanity's footprint or its aggregate ecological demand can only temporarily exceed the productive and assimilative capacity of the biosphere without liquidating and weakening the natural capital on which humanity depends fundamentally. Therefore, accounting tools for quantifying humanity's use of nature are essential for overall assessments of human impact as well as for planning specific steps towards a sustainable future.This paper discusses the strengths and weaknesses of the ecological footprint as an ecological accounting method, points out research needs for improvement of the analysis, and suggests potential new applications. The paper identifies ten new applications of the tool to make it applicable at various geographic scales and for a number of analytical and didactic purposes. Then nine methodological improvements are suggested that could refine the currently applied method, making assessments more sensitive to a larger number of ecological impacts. It concludes that many crucial questions pertinent to building a sustainable society can be addressed by current ecological footprint research. By making the method more complete, this tool could evolve from being largely of pedagogical use to become a strategic tool for policy analysis.     

导布辊辊筒加工用辘头、辘模和辘床

分析了导布辊辊筒加工中的一个重要工艺辘圆工艺。论述了完成这个工艺的装备 ,辘头、辘模和辘床的一些设计方法     

Development of an Earthen Dam Break Database

Earthen embankment dams comprise 85% of all major operational dams in the United States. Assessment of peak flow rates for these earthen dams and the impacts on dam failure are of high interest to engineers and planners. Regression analysis is a frequently used risk assessment approach for earthen dams. In this paper, we present a decision support tool for assessing the applicability of nine regression equations commonly used by practitioners. Using data from 108 case studies, six parameters were observed to be significant factors predicting for peak flow as a metric for risk analysis. We present our work on an expanded earthen dam break database that relates the regression equations and underlying data. A web application, regression selection tool, is also presented to assess the appropriateness of a given model for a given test point. This graphical display allows users to visualize how their data point compares with the data used for the regression equation. These contributions improve estimates and better inform decision makers regarding operational and safety decisions.