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This paper presents a comprehensive safety assessment of hydrogen production using Alkaline Water Electrolysis (AWE). The study utilizes various risk assessment methodologies, including Hazard Identification (HAZID), What-If analysis, Fault Tree Analysis (FTA), Event Tree Analysis (ETA), and Bow Tie analysis, to systematically identify and evaluate potential hazards associated with the AWE process. Key findings include the identification of critical hazards such as hydrogen leaks, oxygen-related risks, and maintenance challenges. The assessment emphasizes the importance of robust safety measures, including preventive and mitigative strategies, to manage these risks effectively. Consequence modeling highlights significant threat zones for thermal radiation and explosion risks, underscoring the need for comprehensive safety protocols and emergency response plans. This work contributes valuable insights into hydrogen safety, providing a framework for risk assessment and mitigation in hydrogen production facilities, crucial for the safe and sustainable development of hydrogen infrastructure in the global energy transition. • Comprehensive safety assessment of hydrogen production via Alkaline Water Electrolysis. • Identification of critical hazards including hydrogen leaks and oxygen-related risks. • Consequence modeling for unignited hydrogen releases and jet fire scenarios. • Emphasis on robust safety protocols and emergency response measures. • Provides practical insights for risk mitigation in hydrogen production facilities. [ABSTRACT FROM AUTHOR]

Probabilistic safety assessment has been widely used to evaluate nuclear power plant safety systems. It couples fault tree (FT) analysis and event tree (ET) analysis. The FT analysis is to develop failure scenarios, to quantify the failure probability, and to identify critical components. The ET analysis is to develop event sequences (ESs) leading to reactor core damage and quantify core damage frequency. Currently, there is no approach in probabilistic safety assessment that can be used to identify minimal combinations of safety system failures leading to reactor core damage. This study proposes an event sequence based fault tree analysis, which integrates the FT model with the ET model. The ET model is to identify the ESs leading to the reactor core damage. Meanwhile, the FT model is to identify minimal combinations of those ESs found in the ET model. The motivation of this study is how to identify critical safety systems in nuclear power plants to mitigate disturbances caused by a group of postulated initiating events to avoid core damage. To confirm the feasibility and the applicability of the proposed approach, the performance of the AP1000 passive core cooling system is evaluated. It is found that if an in-containment refueling water storage tank, an automatic depressurization system - full, an accumulator, a core make-up tank, and a passive residual heat removal work properly, the reactor core will remain intact. These results confirmed that the proposed approach could be applicable to identify minimal combinations of safety systems to keep the reactor core intact. [ABSTRACT FROM AUTHOR]

Objective Levitation controller is a key component of the medium-low speed maglev vehicle, and its reliability directly affects the stability and reliability of the vehicle′s levitation system. Therefore, it is necessary to improve the reliability of the levitation controller. Method With a single levitation electromagnet containing two levitation controllers as the research object, through analyzing the reliability of the levitation controller, its reliability model is established, and a fault tree analysis is conducted to identify the key factors influencing the levitation controller. By transforming two levitation controllers in the single levitation electromagnet into one levitation controller, an optimization scheme for the levitation controller is proposed, together with the redundant design for some key components. Based on the circuit principle of the optimized levitation controller, a reliability model and a fault tree model for the optimized levitation controller are established, and comparison analysis is conducted on the reliability of the levitation controller before and after the optimization. Result & Conclusion Compared with the levitation controller before optimization when a single levitation electromagnet contains two levitation controllers, the total failure rate of which is 2.282×10-6 h-1, the rate of an optimized single levitation electromagnet levitation controller is 1.064×10-6 h-1, a decrease of 53.37%. The reliability of the optimized levitation controller is significantly higher than that of the original one.

Budget allocation in project risk response is a vital issue in project risk management since it relates to a reasonable utilization of strict project budgets and effective mitigations of the risks that typify projects. This paper presents an integrated method based on an optimization model and fault tree analysis for allocating a risk response budget from a preventive and protective perspective. The proposed method consists of three main steps. The first step is to analyse and calculate risk probabilities and risk losses which involves identifying risk causes that may trigger a risk event to occur using fault tree analysis. It also identifies consequences once the risk event occurs, evaluates the occurrence probabilities of risk causes and expected financial losses of consequences. The second step is to build a relationship between the budget allocated to risk response strategies and the corresponding response effects. The third step is to construct an optimization model aiming at minimizing the total risk cost. We present proofs for the optimal risk response strategy in special cases of the budget allocation model. Furthermore, a detailed computational experiment is performed to gain insights into the three-phased budget allocation model for more general cases. The results show that an optimal risk response budget can be determined and the structure of the risk network has a significant impact on the preferred risk response strategy. [ABSTRACT FROM AUTHOR]

The hydraulic system is an integral part of CNC machine tools. In analyzing the reliability of machine tool hydraulic systems, their failures are influenced by both aleatory and epistemic uncertainties. This paper utilizes the fault tree analysis method to address failure modes subject to epistemic uncertainty, using the interval rough number scoring method to evaluate the probability of such failures occurring. The resulting reliability calculation is termed as “subjective reliability”. For failure modes influenced by aleatory uncertainty, objective data combined with the Dempster–Shafer evidence theory is used to determine their failure probability, with the corresponding reliability calculation referred to as “objective reliability”. Finally, a comprehensive calculation of both subjective and objective reliability is conducted to determine the overall reliability of the hydraulic system, along with the ranking of the importance of basic events of fault tree. This methodology covers scenarios with small samples, sufficient data, and their combinations, offering extensive application prospects. [ABSTRACT FROM AUTHOR]

Along with the development of connected vehicle technology, the road traffic flow presents the mixed coexistence development of intelligent networked self-driving vehicles and traditional human-driven vehicles, and it is extremely important to study the risk characteristics of lane change driving behavior of the new networked mixed traffic flow. Based on the safety margin theory, a risk quantification model of lane changing behavior was established, and the fault tree analysis method was used to derive the temporal and spatial risks of lane changing and to quantify the risk assessment of temporal and spatial fusion to determine whether the vehicle was in a safe lane changing state and to provide early warning of the possible risks of vehicle lane changing behavior. The simulation validation analysis of the established quantitative model using SUMO software shows that the mean values of reciprocal of time to collision and instantaneous risk coefficient γ decrease by about 0. 1 and 0. 05, respectively, while the change trend tends to be stable. The safety margin risk quantification model enables the risk of lane change to be effectively controlled while the stability of traffic flow is greatly improved, which can guarantee the steady-state operation of autonomous vehicles queues in the future net connected environment and thus improve traffic capacity and traffic efficiency. [ABSTRACT FROM AUTHOR]

The Safety integrity level (SIL) is a measure of the reliability and availability of a safety instrumented system. SIL determination involves qualitative and quantitative analysis based on international standards such as IEC 61508 and IEC 61511. Several techniques can be used to analyze safety instrumented systems, including reliability block diagrams, fault tree analysis, and Markov models. The aim of this paper is to design and evaluate a pressure control system for a compressed nitrogen tank using a PID controller implemented in a field programmable gate array with 2 out of 3 architecture. This architecture ensures the safety of measurements and command of the system through a voting arrangement. The availability of the system is determined by the redundancy and the one hardware failure tolerance. The quantitative analysis is performed by calculating the probability of failure on demand per hour using Markov models or a relevant probabilistic approach based on fault tree analysis. The Markov model method gives the probability of failure of the system in different states during the system life cycle. The fault tree analysis method determines the probability of failure of the system using its equivalent failure rate. Furthermore, this paper compares the SIL result obtained by each model. [ABSTRACT FROM AUTHOR]

The design for large-scale offshore systems like renewable energy systems as well as ship structures represents the key factor for the investigation and application of such devices. The existing guide for design schemes of offshore systems cannot cover novel large-scale design demand for recent offshore systems, as a result of the fast-growing scale of offshore systems but the late update of guides. To this end, this paper proposes a novel risk estimation approach of alternative design schemes for large-scale offshore systems as a basis to support the design scheme determinations. Initially, the risks of design schemes are analyzed by fault tree analysis. Subsequently, Bayesian networks and fuzzy sets are employed to calculate the reliability of alternative designs that comply with, or deviate from, the existing guides. The risk level of alternative designs is assessed to ensure the better performance of alternative design schemes in terms of safety. The Bayesian network approach proposed also accretions the weak links in the alternative designs. The results of this paper contribute to enhancing the survivability of offshore systems, such as renewable energy systems as well as ship structures.

The main objective of healthcare centers is to ensure a consistent and high-purity oxygen supply for the safety of patients. Pressure Swing Adsorption (PSA) is a commonly used technique for supplying medical oxygen by eliminating nitrogen from the ambient air. Due to the increased fire risk associated with oxygen, any malfunctions in the oxygen supply system can lead to serious hospital fires. This study aimed to assess the reliability of the oxygen supply system using Fault Tree Analysis (FTA) based on both the traditional method and Intuitionistic Fuzzy Analysis. FTA is a logical analysis method used to identify events that could result in an undesirable top event and calculate the probability of its occurrence. The FTA of the PSA system outlined the logical sequence of events that could lead to the release of oxygen as a top event. The study revealed that the failure of the pressure switch in the concentrator, inadequate sealing, and the use of inappropriate materials for the seals were the primary basic events that led to the release of oxygen. Additionally, this study utilized the Intuitionistic Fuzzy System to quantify experts' opinions, providing more flexibility in handling ambiguous situations and considering both membership and non-membership functions simultaneously.

When a trip occurs, the utility of company-type 115/22 kV loading transformer trips out of the electrical system, cutting off power to the distribution of a company customer. The outage damage is valuable at 8.5 US/kWh. A 12-step load transfer procedure at the utility control center takes the operator 433 seconds to complete when restoring power to a customer experiencing an outage. Problem number 1 is that many Supervisor Control and Data Acquisition (SCADA) message alarms will appear during the event, which confuses the operator and possibly leads to an incorrect analysis of the trip event details. Problem number 2 occurs in the process where the operator incorrectly predicts the MW-load data of the Loading Transformer will cause a power outage, causing the neighboring loading transformer to overload and cause damage after the operator completes the LTR process. In this study, Pyauto2, an application developed with the Python platform that connects to the utility control center’s SCADA and runs automatically, is introduced Pyauto2 serves two purposes: to work as an operator to reduce person-hours in the utility company’s LTR process and to analyze find accurate answers to trip events of 68 Loading Transformers installed in the electrical system in the central region of Thailand. The last purpose is to use Pyauto2 to reduce the LTR time. Pyauto2 can analyze the SCADA message alarm via fault tree analysis. To help plan the transfer load, it forecasts MW load data on the day of the loading transformer trip using two-time series forecasting techniques. Holt-Winters exponential smoothing (HWS) method is the second technique, and the triple exponential moving average (TEMA) is the first HWS method. In this study, the distorted data are filtered out via the exponential moving average (EMA) technique before being sent to TEMA and HWS for forecasting. The data gathered between 2017 and 2020 revealed distortion in the MW load data, which may be brought on using SCADA equipment or brief communication failures. Temporary outage, reduced traffic on holidays, and arrangement of the distribution grid route. In this study, the grid search method is compared with limited-memory Broyden-Fletcher–Goldfarb-Shanno (L-BFGS) to modify the alpha-gamma–beta value used in this HWS. The prediction error values of the L-BFGS calculations are lower than those of the grid search method, with a mean absolute error of 0.4576, a mean square error of 0.3996, and a root mean square error of 0.6084. After Pyauto2 is introduced, the average LTR time decreases from 433 s to only 64.88 s, and Pyauto2 works as a substitute for the operator and accurately diagnoses the SCADA alarm, preventing the occurrence of neighbor loading transformer supplying power overload after LTR.INDEX TERMS Fault section diagnosis, transformer restoration, fault tree analysis, exponential moving average, Holt-Winters method, Python language.

In recent years, autonomous driving technology has been developing rapidly, but there is still a certain gap from commercial production, in which the safety issue is one of the important factors. In the working of most companies and colleges, the Traffic Jam Pilot (TJP), serving as a prototypical Level 3 autonomous driving function, has predominantly focused on functional implementation and enhancement, prioritizing functional completeness and user comfort. However, the aspect of functional safety in the system has received comparatively less attention. To guarantee the safety of the driver’s life and property, it is essential to consider the functional safety aspect regarding automobile operation after system function failure. In this paper, according to the functional safety development process and related regulations in ISO 26262, the functions and operation environment of the TJP system are defined in detail, and the longitudinal function is taken as an example to be developed following the functional safety process and verified by simulation. Simulation verification results show that the control algorithm is safe and reliable, and can ensure the safety and stability of the vehicle during operation. The research in this paper further explores the combination of functional safety and high-level automated driving function, providing some ideas for their practical application in industry.

Fault Tree Analysis (FTA) has realized substantial application for safety engineering; however, the method is not without limitations. Traditional FTA requires substantial time and effort, even for single fault assessment, and focuses solely on the probability of event occurrence without considering the severity of consequences. A constrained literature review and examination of functions available in commercial-off-the-shelf FTA software revealed current implementations to lack a structured functional approach to account for severity of intermediate events to a fault as well as severity of fault outcomes. To address this limitation, a novel Consequence Severity-Probability Importance Measure (CSPIM) is proposed as an extension of static FTA. The CSPIM approach is demonstrated through a case study comparing results to those of traditional FTA. Results from a numerical example show that the CSPIM approach effectively prioritizes risky events for safety controls by taking into account both the likelihood and severity of consequences. The CSPIM algorithm calculates a composite risk value and importance of fault tree initiators, revealing those initiators that pose serious risk and should be the focal point for control measures. This approach provides a higher resolution solution than traditional FTA. [ABSTRACT FROM AUTHOR]

EPC project performance is affected by the relation between work processes. E-procurement implemented as a tool to mitigate procurement process risk gives a positive effect and residual risk that needs to be managed further. This research aims to analyze the e-procurement process risk and identify the root causes of critical risks. Data is collected using Focus Group Discussion (FGD) and a questionnaire by 41 e-procurement practitioners from 5 (five) Indonesian construction state-owned enterprises (BUMN). There are 116 risks identified from 22 e-procurement steps, of which three risks are determined as critical risks based on Risk Priority Number analysis, with delay of material requisition document as the highest RPN risk. Fault Tree Analysis identifies that several failure modes, such as miscalculation, misallocation of workforce, and payment issues cause the critical risk. Preparing an in-house engineering team to support the calculation process can mitigate two critical risks at the same time. Risk mitigation causes a residual risk that needs further assessment to determine the proper response. [ABSTRACT FROM AUTHOR]

A comparative study was conducted to compare the accident cause analysis methods of fault tree analysis (FTA) and 24Model. A major accident – the Xinjia Hotel collapse accident – was selected as the research object, the causes of the accident were reanalysed and accident prevention countermeasures were designed based on 24Model and FTA, respectively, and the systematic characteristics of 24Model were summarized. The research shows that both 24Model and FTA can carry out risk assessment, accident cause analysis and preventive countermeasure design based on their own rules. Different from FTA, 24Model has static and dynamic structures of specific forms, the definition of causes and factors in the model is more comprehensive and the analysis method is more hierarchical and normative. 24Model can analyse the deep-level cultural and system causes, but the analysis process does not use quantitative methods, only qualitative methods. 24Model has eight systematic characteristics, such as integrity, hierarchy and dynamics. [ABSTRACT FROM AUTHOR]

Runway excursion accidents in the aircraft landing stage are the emphasis in civil aviation safety management. Correctly analyzing and evaluating the influencing factors of runway excursion accidents are the key issues in the current research. In this study, a fault tree model was established to the runway excursion accident risk in the aircraft landing stage based on the fault tree analysis method. Then, the basic events leading to aircraft runway excursions were summarized, and the minimum cut sets and structural importance were calculated. Next, the probability and critical importance of each basic event and the occurrence probability of the top event were analyzed. Subsequently, a Bayesian network (BN) model was constructed through the identified risk factors for runway excursion accidents of aircrafts. The influencing factors of the occurrence probability of each top event and the relative importance of each basic event were investigated, and the critical risks causing runway excursion accidents of aircrafts were revealed. Results show that, 21 basic events in the runway excursion accidents during aircraft landing, among which system fault, ice and snow accumulation on airport runway pavement, and water accumulation on runway pavement are critical events leading to runway excursions. The obtained conclusions provide a decision-making reference for scientifically managing and controlling runway safety events at transport airports. [ABSTRACT FROM AUTHOR]

DN Tofu Factory is a food industry for tofu products. The company’s main problem is a defect product in October-December 2021 with an average of 7.01%. The purpose of research was to reduce the failure of production in use of the methods of Failure Mode and Effect Analysis (FMEA) and Fault Tree Analysis (FTA). The result of DPMO (Defect per Million Opportunities) calculation is 17500 with a sigma level of 3.6084. Based on the FMEA calculations, two potential causes of failure from the highest perceived value of the RPN (Risk Priority Number), namely that workers do not use the full clothing attributes during the production process with an RPN value of 294 and workers did not pay attention to pressing time with an RPN value of 252. FTA analysis results shows two basic causes of problem, namely workers do not use PPE (Personal Protective Equipment) with a probability of 0.24 and that no tools are available to measure standard time with a probability of 0.2. The proposed improvements implemented by observing the GMP aspect (Good Manufacturing Practice) are to use digital timer, make a tool cleaning form, and make hand-washing posters, smoke free, a restriction on eating and drinking. There is a descrease in the value of DPMO to 16500 with sigma level of 3.6321 after implementation.

Numerous benefits are delivered by the utilization of volumetric modular construction (VMC); however, it carries unique risks at different project stages, which is one of the significant reasons for its low adoption. To date, scant research has adequately examined VMC's risks during projects. This study aims to address this knowledge gap by identifying and assessing critical risk factors (CRFs) within VMC from different stakeholder group perspectives in Australia and New Zealand (NZ). A survey of 110 VMC professionals from Australia and NZ, which examined 31 specific CRFs, was established via a literature review. The CRFs were divided into their associated VMC project stage: (1) design and planning (DP); (2) off-site manufacturing (OM); (3) transport and logistics (TL); and (4) on-site assembly (OA). Fault tree analysis (FTA) was then used to analyze the CRFs. The results indicate that the DP stage risks are the most significant since they could affect VMC's downstream stages. Essential CRFs at each stage were design freeze or change order issues, module geometry conflicts, size and weight restrictions, and dimensional and geometrical variabilities. To the best of the authors' knowledge, this study represents a first attempt at analyzing VMC CRFs in the Australian and NZ construction industry. Overall, this study could contribute to enhancing VMC practices and furthering VMC's adoption as a sustainable and circular construction practice. [ABSTRACT FROM AUTHOR]

This paper deals with the multi-objective optimization of an Emergency Power Supply System (EPSS) in a Nuclear Power Plant (NPP). Two objective functions are considered namely: the maximization of the EPSS reliability and the minimization of the testing cost of two Emergency Diesel Generators (EDGs) considering the Testing Interval (TI) as the control variable of the optimization problem. For doing so, a coupling between the fault tree analysis method (FTA) and the multi-objective optimization is performed. Furthermore, to be more realistic, the effect of ageing is considered. Seven case studies are considered for comparison purpose. An improved version of NSGA-II is proposed considering the integer model of the control variables and the identification of the best compromise solution from the Pareto front. For validation purposes, the boundaries solutions of the Pareto front are compared with those of the mono-objective optimization. The obtained results show clearly that the EPSS aging decreases its reliability. This last can be enhanced by decreasing the testing interval but with additional cost. In addition, the obtained Pareto front provides a set of optimal solutions that can be selected according to the reliability and cost values. [ABSTRACT FROM AUTHOR]

Considering the impact of COVID-19 on hospital facilities and the relevance of risk management and occupational health and safety within this context, this study introduces a method to assess the SARS-CoV-2 virus transmission risk in a toilet. The proposed method is based on a risk tripod involving environmental, human, and transmission factors. For this, risk assessment methodologies were applied, such as Failure Modes and Effects Analysis (FMEA), Ergonomic Work Analysis (EWA), which allowed the identification of risk indicators, and Fault Tree Analysis (FTA), which allowed the identification of transmission routes of COVID-19 in toilets. Subsequently, the Analytic Hierarchy Process (AHP) was used to find each transmission route weighting for calculating the Risk Score. The results indicated that the design of sanitary equipment, with an emphasis on washbasins and toilets, especially in health or large circulation establishments, is of paramount importance in the dissemination of pathogens. Safe habits and the use of protective gear must be continuously encouraged, but greater attention must be paid to technical and engineering issues. Furthermore, the developed method proved to be an applicable tool to identify the main sources of risk and prioritize the implementation of control measures. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agroindustrial Technology / Jurnal Teknologi Industri Pertanian is the property of IPB University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To fulfill high-reliability requirements for aerospace applications, a novel traveling wave rotary ultrasonic motor with a piezoelectric backup function (Backup motor) is proposed in this paper. The backup function is enabled by the addition of a set of piezoelectric ceramics (PZT). Based on the ultrasonic motor of the CSX-60, a cantilever-tooth backup motor (CTBM) is designed and fabricated. This backup motor can operate in three working modes according to the excitation settings of PZTs, namely normal mode, backup mode, and enhanced mode. The relationships between three working modes' performances are analyzed by finite element (FE) analysis and prototype tests. The results show that backup mode, as the substitution, can nearly reach normal mode's performance, while enhanced mode is obviously higher than others. Furthermore, a modified backup motor with straight-tooth (STBM) and different sizes of PZT is designed and tested as a supplement to verify the feasibility of the proposal. In addition, the effect of stress reduction on PZT damage is verified by extreme working experiments. The comparison between the two types of motors indicates that STBM can provide better frictional drive performance. This proposal can provide a new reference for the subsequent reliability study of ultrasonic motors. [ABSTRACT FROM AUTHOR]

Data mining can effectively identify and discover the patterns and inherent laws of accident data. The paper proposes a road traffic accident data mining method based on grey relational clustering. Determine the key influencing factors of road traffic accidents through fault tree analysis method, and achieve accurate quantification of road traffic accident data. Extract the features of road traffic accident data based on EM algorithm. Set the grey relationship analysis factor for road traffic accident data, create a sequence of behavioral feature data, and determine the grey relationship sequence by the operator. Using whitening weight functions to cluster the features of accident data, classify data with consistent features, and achieve road traffic accident data mining. The experimental results show that the designed method has good sensitivity and high grey correlation coefficient in road traffic accident data mining, indicating the feasibility of this method. [ABSTRACT FROM AUTHOR]

This research aims to enhance the quality of automotive components by employing fault tree analysis (FTA) to identify root causes and implement improvements. The FTA method was applied within an Indonesian automotive component manufacturing company specializing in producing Part Stay Protector A Comp. This component is a critical linkage point between exhaust systems and vehicle end caps, playing a crucial role in maintaining vehicle safety and performance. The data analyzed in this study, which led to the root cause determination, primarily originated from customer claims. Among these claims, a notable concern was the off-centre hole in Part Stay Protector A Comp, reflecting one of the Critical To Quality (CTQ) characteristics, with 689 instances of non-conformance. A comprehensive improvement strategy was initiated after identifying root causes through FTA. Utilizing the minimal cut sets (MCSs) method, the analysis underscored that the primary contributor to the fault was identified as (B2) Jig Detection, a critical component within the production process. The Jig Detection system serves as a quality control mechanism, verifying the alignment and conformance of the Part Stay Protector A Comp during production. This strategy focused on minimizing errors in the production method and enhancing the standardization of cup and spot tip classifications to reduce the occurrence of off-centre hole defects. The primary root cause, (B2) Jig Detection, was addressed through an innovative approach that included additional training for labour and introducing a stopper within the Inspection Jig for the Stay Protector A Comp. This strategic enhancement aimed to empower the Inspection Jig to detect off-centre defects, mitigating the recurrence of such issues. Simultaneously, addressing the issue of the nonstandardized cup and spot tip usage classifications aimed to reduce the likelihood of offcentre hole defects reoccurring. The results of these improvements were systematically monitored and controlled over six months, demonstrating a significant reduction in noncentre hole defects. The subsequent results of these improvement efforts profoundly impacted product quality, ultimately reducing the count of off-centre hole defects from 689 to zero, thereby upholding the highest standards in automotive component quality. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Production Engineering / Revista Brasileira de Engenharia de Produção is the property of Brazilian Journal of Production Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The fire-fighting system is one of the proactive technical barriers related to liquefied petroleum gas storage tank safety. This paper presents an integrated approach that uses fuzzy set theory, an improved-dependent uncertain ordered weighted averaging operator and fault tree analysis to handle uncertainty in the unavailability assessment of fire-fighting systems. In this study, the center of area is used to defuzzify triangular fuzzy numbers. Furthermore, for the fire-fighting system fault tree, importance analysis, including Fussell–Vesely importance measure and risk reduction worth of basic events, are performed to identify the weak links of the fire-fighting system. In addition, a real case study on a fire-fighting system for a liquefied petroleum gas storage system in an LPG unit in Algeria is provided to illustrate the effectiveness of the proposed methodology. The research results show that the proposed methodology makes it possible to assess the unavailability of the entire system by analyzing weak links. Consequently, some suggestions are given to take preventive–corrective actions in advance, in order to reduce the failure probability of fire-fighting system and assist the practitioners in setting priorities for improving safety procedures in liquefied petroleum gas storage tanks. The study provides references for analyzing safety barriers in a complex system. [ABSTRACT FROM AUTHOR]

In the contemporary post-truth era, there is a marked increase in the individual’s need for emotional expression and self-awareness. This paper introduces and defines the concept of “Fetish Opposition” through etymological research. Employing fault tree analysis, this study analyzes the risk identification and structural importance of “Fetish Opposition” in the context of “Public Security Prohibition” enforced by police departments. This is approached from the perspective of security system engineering, aiming to elucidate the underlying issues and delineate strategies to mitigate the phenomenon of “anti-public security.” This exploration seeks to provide theoretical guidance for enhancing the effectiveness of public security organs. The findings indicate that “lack of law enforcement transparency” holds structural importance of 0.186 within the fault tree of “Fetish Opposition,” making it the most significant factor affecting the entire system. Based on this insight, the police public relations department could develop targeted strategies to prevent such situations, thereby also opening new avenues for research in social psychology and the stabilization of police-community relations.

In developing countries, ultra-high-performance concrete (UHPC) has not garnered sufficient attention, and its potential industrial applications remain largely unexplored and underdeveloped. The purpose of this paper is to assess the risk associated with integrating UHPC technology into the construction industry, focusing on economic, technical, and environmental facets, as highlighted by global research endeavors in this domain. In this study, a risk model is validated by analyzing diverse UHPC mix proportions from various studies and assessing the associated risk indices concerning constituent materials. The findings demonstrate that incorporating UHPC as a more robust alternative to earlier generations is plausible when considering multiple perspectives within the concrete industry. The preeminence of compressive strength and the significance of service life as a pivotal cost factor during the maintenance period, coupled with comprehensive risk indices, underscore the excellence of UHPC. Comparing UHPC with high-performance concrete (HPC) and normal concrete (NC), it becomes evident that UHPC exerts a notably lower adverse impact on the ecosystem. Additionally, UHPC proves to be a more economically viable option, warranting the replacement of existing technologies.

Maintenance of production machines is the key to success for increasing the efficiency of production machines. The value of OEE (overall Equipment Effectiveness) is an important indicator of the level of effectiveness of production machines. The grinding machine at the cocoa powder company PT ABC Sidoarjo is a production machine that is considered to have the greatest contribution to achieving OEE values. However, up to now, the machine maintenance is only corrective so it has the potential to harm the company. The purpose of this study is to determine the effectiveness of the grinding machine and formulate recommendations for improvement. The method used is the six big losses analysis technique to identify the dominant type of loss, and the FTA (Fault Tree Analysis) technique to determine the root cause. The results of the analysis show that the OEE value of the grinding machine is only 45% (low). The types of losses that contributed greatly to these conditions were reduced speed losses by 41% and were categorized as bad. This is due to the absence of regular replacement of the grinding machine blades so that their performance is less stable. In addition, the values of idling and minor stoppages and set up and adjustment losses are also categorized as bad because of the frequent occurrence of wasted processing time. Only rework losses are categorized as good. A low OEE value indicates that the machine is still not working effectively. Recommendations for improvements that can be done are performing independent maintenance, forming a competent small group, arranging planned maintenance for replacing machine blades and installing vibrators on peripheral pipes

With the development of multi-electric aircraft, the researches on the structure improvement and fault di-agnosis of aviation transformer rectifier units (TRUs) are increasing, but research on the characteristics and effects of typical fault modes of different types of TRUs is lacked. Based on the analysis of TRUs structures, the failure mode and effects analysis (FMEA) and fault tree analysis (FTA) of TRUs are studied to determine typical failure modes of TRUs. Then, simulation models of various TRUs are established by Simulink, and the electrical signal characteristics of TRUs under different fault modes are analyzed and compared; the detailed fault modes of 8 TRUs are defined. The results show that the hard faults of TRUs have great impact on the system, and the high-pulse TRUs have better stability under fault modes and lower reliability.

The hydrogen-electric coupling system is an important and indispensable part of a new-type power system， and its safety is a prerequisite for large-scale application. The hydrogen-electric coupling system is studied， and the accidents in key hydrogen-related equipment are summarized and investigated.Furthermore， fault tree analysis （FTA） is used for safety risk evaluation on the combustion and explosion of the hydrogen-electric coupling system caused by hydrogen leakage. The study shows that hydrogen storage and compression equipment is prone to safety accidents， and design defects， sealing， and operation errors are major causes of hydrogen accidents. The fault tree analysis shows that there are five ways to effectively prevent the hydrogen-electric coupling system from fire or explosion due to hydrogen leakage. The importance of the hazard sources and basic events of the system obtained from the study lays the foundation for developing safety protection measures.

Aim. Compressed air vessels are responsible for injecting compressed air to the mechanical flying device. It should be noted that the pressure level inside these vessels is very important in conducting all operational stages successfully; therefore, it is of high significance to be assured of the quality of the vessels being used. This study was done in 2017 in order to calculate and estimate the reliability of compressed air vessels in mechanical flying device system with proposing a potential failures assessment and accelerated test approach taking into consideration the current methods. Methods. The paper uses methods of Fault Tree Analysis, Failure Mode & Effect Analysis and Accelerator tests. Initially, the interactions among the components were identified using the Design Structure Matrix in order to design a matrix to help estimate the reliability; consequently, improve equipment performance. Next, failures root recognition was done using Fault Tree Analysis diagram, then, failures reasons prioritization was done using Failure Mode & Effects Analysis tables. Accelerator tests were designed and applied on failure mechanisms such as leakage by pressure on vessels, corrosions on steal head, nipples, O-ring creeping, O-ring ozone cracking and liner chemical degradation. After that, the average of failure rates was calculated within the taking after stage for each test. Within the conclusion, the result of failure rates from the accelerator tests was compared with the result of failure rates from the process approach. Consequently, the most elevated amount of these two approaches was defined as the total failure rate; product reliability and lifetime were calculated utilizing this amount. Results. The following finding were obtained using the proposed methods. When Windy Liner was used, vessel lifetime was six years and half and vessel reliability in ten years was 0/22. Whereas, when Rotational Liner was used, vessel lifetime was eight years and three months and vessel reliability in ten years was 0/3. Conclusion. The approach proposed in the paper allows accelerator degradation test can also be used instead of accelerated test in order to calculate the reliability of failure mechanisms. In the event that high-quality and legitimate O-rings are used, vessel reliability and lifetime can be increased. [ABSTRACT FROM AUTHOR]

Expert knowledge is the key to modeling milling fault detection systems based on the belief rule base. The construction of an initial expert knowledge base seriously affects the accuracy and interpretability of the milling fault detection model. However, due to the complexity of the milling system structure and the uncertainty of the milling failure index, it is often impossible to construct model expert knowledge effectively. Therefore, a milling system fault detection method based on fault tree analysis and hierarchical BRB (FTBRB) is proposed. Firstly, the proposed method uses a fault tree and hierarchical BRB modeling. Through fault tree analysis (FTA), the logical correspondence between FTA and BRB is sorted out. This can effectively embed the FTA mechanism into the BRB expert knowledge base. The hierarchical BRB model is used to solve the problem of excessive indexes and avoid combinatorial explosion. Secondly, evidence reasoning (ER) is used to ensure the transparency of the model reasoning process. Thirdly, the projection covariance matrix adaptation evolutionary strategies (P-CMA-ES) is used to optimize the model. Finally, this paper verifies the validity model and the method's feasibility techniques for milling data sets. [ABSTRACT FROM AUTHOR]

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In developing countries, ultra-high-performance concrete (UHPC) has not garnered sufficient attention, and its potential industrial applications remain largely unexplored and underdeveloped. The purpose of this paper is to assess the risk associated with integrating UHPC technology into the construction industry, focusing on economic, technical, and environmental facets, as highlighted by global research endeavors in this domain. In this study, a risk model is validated by analyzing diverse UHPC mix proportions from various studies and assessing the associated risk indices concerning constituent materials. The findings demonstrate that incorporating UHPC as a more robust alternative to earlier generations is plausible when considering multiple perspectives within the concrete industry. The preeminence of compressive strength and the significance of service life as a pivotal cost factor during the maintenance period, coupled with comprehensive risk indices, underscore the excellence of UHPC. Comparing UHPC with high-performance concrete (HPC) and normal concrete (NC), it becomes evident that UHPC exerts a notably lower adverse impact on the ecosystem. Additionally, UHPC proves to be a more economically viable option, warranting the replacement of existing technologies. [ABSTRACT FROM AUTHOR]

The prevention and control of gas explosion accidents are important means to improving the level of coal mine safety, and risk assessment has a positive effect on eliminating the risk of gas explosions. Aiming at the shortcomings of current risk assessment methods in dynamic control, state expression and handling uncertainty, this study proposes a method combining fault tree analysis and fuzzy polymorphic Bayesian networks. The risk factors are divided into multiple states, the concept of accuracy is proposed to correct the subjectivity of fuzzy theory and Bayesian networks are relied on to calculate the risk probability and risk distribution in real time and to propose targeted prevention and control measures. The results show that the current risk probability of a gas explosion accident in Wangzhuang coal mine is as high as 35%, and among the risk factors, excessive ventilation resistance and spontaneous combustion of coal are sources of induced risk, and the sensitivity value of electric sparks is the largest, and the prevention and control of the key factors can significantly reduce the risk. This study can provide technical support to coal mine gas explosion risk management. [ABSTRACT FROM AUTHOR]