An Integrated Approach-Based FMECA for Risk Assessment: Application to Offshore Wind Turbine Pitch System

Improved Z-number and fault tree analysis to predict the risk of air pollution due to ship boiler operation

Ships present a significant source of air pollution, contributing to environmental degradation and posing health risks. Boilers are a significant part of the vessels in which the water is heated to evaporate and generate steam. The boilers emit pollutants such as hazardous air pollutants (HAPs), particle pollution, and volatile organic compounds (VOC). This paper conducts an extended risk analysis for air pollution due to boiler operation on ships. An improved Z-numbers theory and Fault Tree Analysis (FTA) are adopted to predict risk. Whilst improved Z-number theory is capable of handling uncertainties inherent in risk assessment, the FTA presents systematically the causal relationships among various factors contributing to the risk of air pollution on ships. The findings show that the failure probability of air pollution during ship boiler operation is 2.08E-05 and BE-12 is the most significant event. Results provide valuable data to maritime stakeholders in fostering environmentally sustainable practices.

Towards Trustworthy Safety Assessment by Providing Expert and Tool-Based XMECA Techniques

Safety assessment of modern critical instrumentation and control systems is a complicated process considerably dependent on expert techniques, single/multiple faults consideration scope, other assumptions, invoked limitations, and support tools used during the assessment process. Ignoring these assumptions, as well as the significance of expert and tool influence, could lead to such effects as functional safety underestimation or overestimation in such a manner that functional safety assessment correctness and accuracy are affected. This paper introduces XMECA (x modes, effects, and criticality analysis, where x could be from different known techniques and domains—failures in functional safety, vulnerabilities and intrusions regarding cybersecurity, etc.) as a key technique of safety assessment. To verify the results obtained as XMECA deliverables, expert and uncertainty modes, effects, and criticality analysis (EUMECA) is performed, in particular focusing on decisions and judgments made by experts. Scenarios for processing verbal and quantitative information of XMECA tables from experts are offered. A case study of a possible functional safety assessment approach that considers the above-mentioned techniques and a supporting tool is provided. To assess the trustworthiness of safety analysis and estimation using XMECA, a set of the metrics is suggested. Features of adapting the suggested method for security assessment considering intrusions, vulnerabilities, and effects analysis (IMECA technique) are discussed.

Obstacle Identification and Analysis to the Commercialization of CCUS Technology in China under the Carbon Neutrality Target

As the largest emitter of carbon dioxide all over the world, China requires a rapid breakthrough and large-scale commercial application of carbon capture, utilization and sequestration (CCUS) technology to achieve the 2060 carbon neutrality target. However, the process of CCUS technology commercialization in China is quite slow. Firstly, an obstacle system with 15 factors is established based on a literature review and expert consultation, namely on economic, technical, political, market, and social obstacles. Secondly, taking into account the uncertainty and randomness inherent in subjective judgment, Vague set is introduced for the first time to improve the DEMATEL-ANP (DANP) method in order to analyze comprehensive importance and causal relationship of obstacles. According to the study, in advancing CCUS’s commercialization in China, economic obstacles are simply the tip of the iceberg, with the deeper reasons rooted in political obstacles. Specifically, seven critical obstacles are lack of standards and regulations, inadequate legal and regulatory framework, insufficient incentive policies, limited carbon dioxide conversion efficiency, high energy consumption, low rate of return on investments and low investment enthusiasm of enterprise. We conclude with a series of recommendations to address these obstacles, and these findings can be used as a guide for government regulation and business practice.