The use of SVM-FFA in estimating fatigue life of polyethylene terephthalate modified asphalt mixtures

To predict fatigue life of Polyethylene Terephthalate (PET) modified asphalt mixture, various soft computing methods such as Genetic Programming (GP), Artificial Neural Network (ANN), and Fuzzy Logic-based methods have been employed. In this study, an application of Support Vector Machine Firefly Algorithm (SVM-FFA) is implemented to predict fatigue life of PET modified asphalt mixture. The inputs are PET percentages, stress levels and environmental temperatures. The performance of proposed method is validated against observed experiment data. The results of the prediction using SVM-FFA are then compared to those of applying ANN and GP approach and it is concluded that SVM-FFA leads to more accurate results when compared to observed experiment data.     

Model for practical prediction of natural carbonation in reinforced concrete: Part 1-formulation

A model is proposed for prediction of natural carbonation in reinforced concrete (RC) structures, and is potentially applicable to existing and new RC structures. The major components of the model comprise mathematical functions applied to predict the influence of concrete composition, and environmental factors on natural carbonation.This paper introduces the model concept and explains its structure including derivation, optimization and calibration. Over 163 data sets taken from a 10-year carbonation study were used in the model development and calibration. Only the experimental data that were based on outdoor natural exposure environment were employed in this research. Also in this study, the proposed model is compared with fib-Model Code 2010 using carbonation predictions generated from 346 data sets involving real world, highway structures. It is shown that the proposed model is comparably accurate and involves mainly basic tests with no major anticipated costs.     

An approach to conceptual and embodiment design within a new product development lifecycle framework

The design of new innovative products is the result of an accurate and precise management of knowledge sources all over its life cycle, such as technology, market, competitors and suppliers. The work contributes with a framework that shows how the knowledge sources influence in the state-of-the-art and market needs so that they become opportunities for innovating products addressing the whole product life cycle. It provides a systematic path from the early generation of ideas to the production of a new product proposal. Through a deep analysis of previous research works of new product innovation life cycle development frameworks and linking it with knowledge management, strategic planning and scorecards, we came out with a structured contribution. The result considers the concurrent activities and its relationships all the way through the product life cycle that can help in creativity and innovation, combined with a process management proposal. Managing the sources of knowledge in highly dynamic markets and technologies is one of the major difficulties involved in innovative products design and development. The emerging knowledge from external sources is confronted with organisation internal knowledge and experience in order to achieve the first product correct.     

上海市诺如病毒感染性腹泻疾病负担的评估

目的对上海市诺如病毒感染性腹泻的疾病负担进行综合评估,为管理部门制定预防和控制诺如病毒感染的措施提供依据。方法结合上海市哨点医院诺如病毒感染性腹泻监测和诺如病毒感染暴发事件报告,采用伤残调整寿命年(DALYs)、发病率、就诊率和住院率等指标对上海市诺如病毒感染性腹泻的疾病负担进行评估。结果 2015年上海市感染性腹泻发病人数为483.05万人,其中诺如病毒感染性腹泻的发病人数为123.23万人,住院病例为370人,所产生的疾病负担为2 938.98 DALYs,即0.12 DALYs/千人。结论上海市诺如病毒感染性腹泻的疾病负担相对较高,需要加强预防控制。     

Life prediction of stainless steels by cyclic and stable hysteresis curves

Abstract

This study develops an analytical expression to describe the cyclic stress‐strain curve obtained from a series of fully‐reversed fatigue tests. A set of stress‐strain relationships is proposed to simulate the tensile branch of the stable hysteresis loop. The complete shape of the stable hysteresis loop is then constructed and the associated theoretical plastic work calculated by integrating the area within the enclosed curve. The theoretical plastic work is employed to predict the fatigue lives of the investigated materials on the basis of their respective stable plastic work per cyclelife curves. In this paper, the current mathematical derivations are based upon the endochronic theory of plasticity. The accuracy of the proposed set of stress‐strain relationships is verified by conducting fully‐reversed constant strain amplitude fatigue tests on AISI 316 and AISI 304 stainless steels. The experimental and simulation results are found to be in good agreement, hence confirming the accuracy of the proposed analytical stress‐strain relationships. Again, comparing the obverted and predicted fatigue lives, a good agreement is found between the two sets of results.     

煤矿项目全生命周期工程造价管理

介绍了煤矿项目造价管理的发展历程,分析了目前煤矿产业的发展现状,具体说明了全生命周期工程造价管理在煤矿项目中的各个阶段的实施过程。     

铅膏含酸量对铅酸蓄电池性能影响的图像分析

铅膏材料的晶相受其材料含酸量的影响显著,而且在化成时正极铅膏的晶相会发生取代反应,对其活性物质的微观结构及机械强度产生直接影响,除此之外,还会影响铅酸蓄电池的循环寿命。通过计算机图像辅助研究了铅酸蓄电池中正极铅膏的含酸量对电池循环寿命的影响,研究表明当正极铅膏的含酸量为7%~8%时电池的性能最佳。     

湿法气流床气化炉耐火材料使用寿命的探讨

针对湿法气流床气化炉耐火材料损耗严重的问题,从块状剥落、烧蚀损伤、冲蚀损伤、化学侵蚀4方面进行了原因分析,提出可以通过合理选煤、改善工艺、合理选材及精心筑炉等手段延长耐火砖寿命。