On the development of the new harmonised damage stability regulations for dry cargo and passenger ships

This paper outlines the methodological background and presents a summary of the main results of a series of undertaken international, IMO-led studies, on the harmonisation of the new probabilistic, risk-based regulations with the currently in-force regulatory provisions for assessing the damage stability of dry cargo and passenger ships. It reviews the historical development of the new regulations, to be applied to all new buildings on January 1, 2009, and the anticipated impact of the new rules on the design and indirect operation of various subcategories of dry cargo and passenger ships. It identifies certain loopholes in the existing regulations that appear cured by the new ones, though certain compromises adopted in the development of the new regulations, particularly those related to large passenger ships’ survivability, have left some open issues to be addressed in the near future.     

Principles of engineering safety: Risk and uncertainty reduction

This article provides a systematised account of safety engineering practices that clarifies their relation to the goal of safety engineering, namely to increase safety. We list 24 principles referred to in the literature of safety engineering, dividing them into four major categories: Inherently safe design, Safety reserves, Safe fail and Procedural safeguards. It emerges from this systematisation that important aspects of these methods can be better understood with the help of the distinction between risk and uncertainty.     

船用核动力装置部件失效分析与安全评定

主螺栓是船用核动力装置的重要部件,通过微观形貌观察和腐蚀产物分析,研究了断裂与未断裂主螺栓的失效原因,结果表明:失效主要是由应力腐蚀引起的;应用断裂力学方法对主螺栓进行了安全评定,计算出其临界裂纹尺寸为4.2 mm,可作为主螺栓安全评定的依据,且具有足够的安全余量.     

The human error rate assessment and optimizing system HEROS — a new procedure for evaluating and optimizing the man–machine interface in PSA

A new procedure allowing the probabilistic evaluation and optimization of the man–machine system is presented. This procedure and the resulting expert system HEROS, which is an acronym for Human Error Rate Assessment and Optimizing System, is based on the fuzzy set theory. Most of the well-known procedures employed for the probabilistic evaluation of human factors involve the use of vague linguistic statements on performance shaping factors to select and to modify basic human error probabilities from the associated databases. This implies a large portion of subjectivity. Vague statements are expressed here in terms of fuzzy numbers or intervals which allow mathematical operations to be performed on them. A model of the man–machine system is the basis of the procedure. A fuzzy rule-based expert system was derived from ergonomic and psychological studies. Hence, it does not rely on a database, whose transferability to situations different from its origin is questionable. In this way, subjective elements are eliminated to a large extent. HEROS facilitates the importance analysis for the evaluation of human factors, which is necessary for optimizing the man–machine system. HEROS is applied to the analysis of a simple diagnosis of task of the operating personnel in a nuclear power plant.     

A method for risk-informed safety significance categorization using the analytic hierarchy process and bayesian belief networks

A risk-informed safety significance categorization (RISSC) is to categorize structures, systems, or components (SSCs) of a nuclear power plant (NPP) into two or more groups, according to their safety significance using both probabilistic and deterministic insights. In the conventional methods for the RISSC, the SSCs are quantitatively categorized according to their importance measures for the initial categorization. The final decisions (categorizations) of SSCs, however, are qualitatively made by an expert panel through discussions and adjustments of opinions by using the probabilistic insights compiled in the initial categorization process and combining the probabilistic insights with the deterministic insights. Therefore, owing to the qualitative and linear decision-making process, the conventional methods have the demerits as follows: (1) they are very costly in terms of time and labor, (2) it is not easy to reach the final decision, when the opinions of the experts are in conflict and (3) they have an overlapping process due to the linear paradigm (the categorization is performed twice—first, by the engineers who propose the method, and second, by the expert panel). In this work, a method for RISSC using the analytic hierarchy process (AHP) and bayesian belief networks (BBN) is proposed to overcome the demerits of the conventional methods and to effectively arrive at a final decision (or categorization). By using the AHP and BBN, the expert panel takes part in the early stage of the categorization (that is, the quantification process) and the safety significance based on both probabilistic and deterministic insights is quantified. According to that safety significance, SSCs are quantitatively categorized into three categories such as high safety significant category (Hi), potentially safety significant category (Po), or low safety significant category (Lo). The proposed method was applied to the components such as CC-V073, CV-V530, and SI-V644 in Ulchin Unit 3 NPP in South Korea. The expert panel consisted of two probabilistic safety assessments (PSA) experts and one system design expert. Before categorizing the components, the design basis functions, simplified P and IDs, and the Fussell-Vesely (FV) importance and the Risk Achievement Worth (RAW) of the PSA were prepared for the experts' evaluations. By using this method, we could categorize the components quantitatively on the basis of experts' knowledge and experience in an early stage.     

基于危险分析与风险评价的液压提升机安全设计

介绍了液压提升机的安全性能要求,对液压提升机进行了危险分析和风险评价,确定了各子系统的危险分值,得到了安全设计中必须高度关注的子系统;进行了各子系统的安全可靠度的预计与分配,并简要分析了子系统的安全设计要点,为液压提升机的安全可靠性分析与设计提供了依据。     

基于NX平台的船舶三维趾端结构自动CAE理想化方法研究

目的提出船舶模型中趾端结构的CAE理想化方法,提高船舶有限元前处理中趾端简化的效率。方法采用三维八叉树搜索算法,建立三维趾端与相邻空间船舶结构的空间位置关系,筛选需要简化的趾端结构,根据趾端简化规则进行处理。结果基于NX11.0平台,开发出趾端结构理想化功能,实现趾端结构CAE理想化处理的自动化过程,并使用实际船型测试,处理结果满足有限元网格划分质量要求。结论该方法能准确、高效地实现趾端结构自动理想化处理。     

基于最大熵原理的复合形法及其在边坡稳定分析中的应甩

将最大熵原理应用于基本复合形法的优化计算中,旨在提高算法的寻优成功率.具体步骤为选取复形中熵最大的顶点为寻优点;在复形其余各点的加权中心点与寻优点的连线上,搜索比寻优点改善的新顶点;并替换掉寻优点构成新的复形;如此迭代直至复形中的信息被完全利用.采用基本复合形法和基于最大熵原理的复合形法对两个复杂土坡的最小安全系数进行了搜索,结果表明基于最大熵原理的复合形法的全局搜索能力有了明显改善.     

Safety assessment in plant layout design using indexing approach: implementing inherent safety perspective. Part 1 - guideword applicability and method description

Layout planning plays a key role in the inherent safety performance of process plants since this design feature controls the possibility of accidental chain-events and the magnitude of possible consequences. A lack of suitable methods to promote the effective implementation of inherent safety in layout design calls for the development of new techniques and methods. In the present paper, a safety assessment approach suitable for layout design in the critical early phase is proposed. The concept of inherent safety is implemented within this safety assessment; the approach is based on an integrated assessment of inherent safety guideword applicability within the constraints typically present in layout design. Application of these guidewords is evaluated along with unit hazards and control devices to quantitatively map the safety performance of different layout options. Moreover, the economic aspects related to safety and inherent safety are evaluated by the method. Specific sub-indices are developed within the integrated safety assessment system to analyze and quantify the hazard related to domino effects. The proposed approach is quick in application, auditable and shares a common framework applicable in other phases of the design lifecycle (e.g. process design). The present work is divided in two parts: Part 1 (current paper) presents the application of inherent safety guidelines in layout design and the index method for safety assessment; Part 2 (accompanying paper) describes the domino hazard sub-index and demonstrates the proposed approach with a case study, thus evidencing the introduction of inherent safety features in layout design.     

Safety assessment in plant layout design using indexing approach: implementing inherent safety perspective. Part 2-Domino Hazard Index and case study

The design of layout plans requires adequate assessment tools for the quantification of safety performance. The general focus of the present work is to introduce an inherent safety perspective at different points of the layout design process. In particular, index approaches for safety assessment and decision-making in the early stages of layout design are developed and discussed in this two-part contribution. Part 1 (accompanying paper) of the current work presents an integrated index approach for safety assessment of early plant layout. In the present paper (Part 2), an index for evaluation of the hazard related to the potential of domino effects is developed. The index considers the actual consequences of possible escalation scenarios and scores or ranks the subsequent accident propagation potential. The effects of inherent and passive protection measures are also assessed. The result is a rapid quantification of domino hazard potential that can provide substantial support for choices in the early stages of layout design. Additionally, a case study concerning selection among various layout options is presented and analyzed. The case study demonstrates the use and applicability of the indices developed in both parts of the current work and highlights the value of introducing inherent safety features early in layout design.     

Knowledge,attitude and practices for design for safety: A study on civil & structural engineers

Design for safety (DfS) (also known as prevention through design, safe design and Construction (Design and Management)) promotes early consideration of safety and health hazards during the design phase of a construction project. With early intervention, hazards can be more effectively eliminated or controlled leading to safer worksites and construction processes. DfS is practiced in many countries, including Australia, the UK, and Singapore. In Singapore, the Manpower Ministry enacted the DfS Regulations in July 2015, which will be enforced from August 2016 onwards. Due to the critical role of civil and structural (C&S) engineers during design and construction, the DfS knowledge, attitude and practices (KAP) of C&S engineers have significant impact on the successful implementation of DfS. Thus, this study aims to explore the DfS KAP of C&S engineers so as to guide further research in measuring and improving DfS KAP of designers. During the study, it was found that there is a lack of KAP studies in construction management. Therefore, this study also aims to provide useful lessons for future applications of the KAP framework in construction management research. A questionnaire was developed to assess the DfS KAP of C&S engineers. The responses provided by 43 C&S engineers were analyzed. In addition, interviews with experienced construction professionals were carried out to further understand perceptions of DfS and related issues. The results suggest that C&S engineers are supportive of DfS, but the level of DfS knowledge and practices need to be improved. More DfS guidelines and training should be made available to the engineers. To ensure that DfS can be implemented successfully, there is a need to study the contractual arrangements between clients and designers and the effectiveness of different implementation approaches for the DfS process. The questionnaire and findings in this study provided the foundation for a baseline survey with larger sample size, which is currently being planned. In contrast to earlier studies, the study showed that the responding C&S engineers were supportive of the DfS. The study showed that the key to improving the DfS KAP of C&S engineers is by improving clients’ motivation for DfS.     

Stability Analysis of Transfer Alignment Filter Based on the μ Theory

The performance of the transfer alignment has great impact on inertial navigation systems. As the transfer alignment is generally implemented using a filter to compensate the errors, its accuracy, rapidity and anti-disturbance capability are key properties to evaluate the filtering process. In terms of the superiority in dealing with the noise, H∞ filtering has been used to improve the anti-disturbance capability of the transfer alignment. However, there is still a need to incorporate system uncertainty due to various dynamic conditions. Based on the structural value theory, a robustness stability analysis method has been proposed for the transfer alignment to evaluate the impact of uncertainty on the navigation system. The mathematical derivation has been elaborated in this paper, and the simulation has been carried out to verify the effectiveness of the algorithm.     

Dynamic modeling of the tradeoff between productivity and safety in critical engineering systems

Short-term tradeoffs between productivity and safety often exist in the operation of critical facilities such as nuclear power plants, offshore oil platforms, or simply individual cars. For example, interruption of operations for maintenance on demand can decrease short-term productivity but may be needed to ensure safety. Operations are interrupted for several reasons: scheduled maintenance, maintenance on demand, response to warnings, subsystem failure, or a catastrophic accident. The choice of operational procedures (e.g. timing and extent of scheduled maintenance) generally affects the probabilities of both production interruptions and catastrophic failures. In this paper, we present and illustrate a dynamic probabilistic model designed to describe the long-term evolution of such a system through the different phases of operation, shutdown, and possibly accident. The model's parameters represent explicitly the effects of different components' performance on the system's safety and reliability through an engineering probabilistic risk assessment (PRA). In addition to PRA, a Markov model is used to track the evolution of the system and its components through different performance phases. The model parameters are then linked to different operations strategies, to allow computation of the effects of each management strategy on the system's long-term productivity and safety. Decision analysis is then used to support the management of the short-term trade-offs between productivity and safety in order to maximize long-term performance. The value function is that of plant managers, within the constraints set by local utility commissions and national (e.g. energy) agencies. This model is illustrated by the case of outages (planned and unplanned) in nuclear power plants to show how it can be used to guide policy decisions regarding outage frequency and plant lifetime, and more specifically, the choice of a reactor tripping policy as a function of the state of the emergency core cooling subsystem.     

Low‐Cost and Highly Efficient Carbon‐Based Perovskite Solar Cells Exhibiting Excellent Long‐Term Operational and UV Stability

Today's perovskite solar cells (PSCs) mostly use components, such as organic hole conductors or noble metal back contacts, that are very expensive or cause degradation of their photovoltaic performance. For future large‐scale deployment of PSCs, these components need to be replaced with cost‐effective and robust ones that maintain high efficiency while ascertaining long‐term operational stability. Here, a simple and low‐cost PSC architecture employing dopant‐free TiO₂ and CuSCN as the electron and hole conductor, respectively, is introduced while a graphitic carbon layer deposited at room temperature serves as the back electrical contact. The resulting PSCs show efficiencies exceeding 18% under standard AM 1.5 solar illumination and retain ≈95% of their initial efficiencies for >2000 h at the maximum power point under full‐sun illumination at 60 °C. In addition, the CuSCN/carbon‐based PSCs exhibit remarkable stability under ultraviolet irradiance for >1000 h while under similar conditions, the standard spiro‐MeOTAD/Au based devices degrade severely.     

基于可视化的事故树分析系统研究与开发

事故树分析是安全系统工程最重要的分析方法之一，它能对各种系统的危险性进行辨识和评价，不仅能分析出事故的直接原因，而且能深入地揭示出事故的潜在原因。用它描述事故的因果关系直观、明了，思路清晰，逻辑性强，既可定性分析，又可定量分析。基于可视化理论和技术，建立了事故树可视化模型，确定了系统功能目标，完成了系统结构设计，构造了事故树图形生成与事故树动态分析于一体的集成分析环境，开发出事故树计算机分析系统，为事故分析和安全评价提供高效、准确的技术和方法。     

Sulfide‐Based Solid‐State Electrolytes: Synthesis,Stability, and Potential for All‐Solid‐State Batteries

Due to their high ionic conductivity and adeciduate mechanical features for lamination, sulfide composites have received increasing attention as solid electrolyte in all‐solid‐state batteries. Their smaller electronegativity and binding energy to Li ions and bigger atomic radius provide high ionic conductivity and make them attractive for practical applications. In recent years, noticeable efforts have been made to develop high‐performance sulfide solid‐state electrolytes. However, sulfide solid‐state electrolytes still face numerous challenges including: 1) the need for a higher stability voltage window, 2) a better electrode–electrolyte interface and air stability, and 3) a cost‐effective approach for large‐scale manufacturing. Herein, a comprehensive update on the properties (structural and chemical), synthesis of sulfide solid‐state electrolytes, and the development of sulfide‐based all‐solid‐state batteries is provided, including electrochemical and chemical stability, interface stabilization, and their applications in high performance and safe energy storage.     

禹门口扩建泵站岩坎爆破拆除与安全控制

针对禹门口黄河提水工程中扩建泵站预留岩坎爆破拆除难度较大的情况,采用深孔爆破和预裂爆破相结合、高精度塑料导爆管雷管延时起爆的爆破技术,钻孔分角度布孔,岩坎分区单耗,爆破总药量3 633kg,总方量3 500m³;综合炸药单耗1.04kg/m3;综合炸药单耗1.04kg/m³,控制最大单响药量24kg。岩坎爆破从中部开口起爆,地表传爆雷管孔间、排间延时为17、25、65ms,保证每个炮孔按照延时起爆不重段,实现了精准爆破。采取严格周密的安全防护措施和振动监测,爆破过程中未见飞石和涌浪,各建筑物实测振速均小于安全标准,保障了一级泵站、扩建泵站、周围交通设施的安全。岩坎爆破拆除取得成功,爆破效应得以有效控制,设计参数和控制标准可供类似工程参考。