scholarly journals Safety Assessment of Casting Workshop by Cloud Model and Cause and Effect–LOPA to Protect Employee Health

Author(s):  
Qingwei Xu ◽  
Kaili Xu ◽  
Fang Zhou

Safety assessment of a casting workshop will provide a clearer understanding of the important safety level required for a foundry. The main purpose of this study was to construct a composite safety assessment method to protect employee health using the cloud model and cause and effect–Layer of Protection Analysis (LOPA). In this study, the weights of evaluation indicators were determined using the subjective analytic hierarchy process and objective entropy weight method respectively. Then, to obtain the preference coefficient of the integrated weight more precisely, a new algorithm was proposed based on the least square method. Next, the safety level of the casting workshop was presented based on the qualitative and quantitative analysis of the cloud model, which realized the uncertainty conversion between qualitative concepts and their corresponding quantitative values, as well as taking the fuzziness and randomness into account; the validity of cloud model evaluation was validated by grey relational analysis. In addition, cause and effect was used to proactively identify factors that may lead to accidents. LOPA was used to correlate corresponding safety measures to the identified risk factors. 6 causes and 19 sub-causes that may contribute to accidents were identified, and 18 potential remedies, or independent protection layers (IPLs), were described as ways to protect employee health in foundry operations. A mechanical manufacturing business in Hunan, China was considered as a case study to demonstrate the applicability and benefits of the proposed safety assessment approach.

Author(s):  
Ievgen Babeshko ◽  
Kostiantyn Leontiiev

Safety assessment of nuclear power plant instrumentation and control systems (NPP I&Cs) is a complicated and resource-consuming process that is required to be done so as to ensure the required safety level and comply to normative regulations. A lot of work has been performed in the field of application of different assessment methods and techniques, modifying them, and using their combinations so as to provide a unified approach in comprehensive safety assessment. Performed research has shown that there are still challenges to overcome, including rationale and choice of the safety assessment method, verification of assessment results, choosing and applying techniques that support safety assessment process, especially in the nuclear field. This chapter presents a developed framework that aggregates the most appropriate safety assessment methods typically used for NPP I&Cs.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
X. B. Gu ◽  
S. T. Wu ◽  
X. J. Ji ◽  
Y. H. Zhu

The debris flow is one of the geological hazards; its occurrence is complex, fuzzy, and random. And it is affected by many indices; a new multi-index assessment method is proposed to analyze the risk level of debris flow based on the entropy weight-normal cloud model in Banshanmen gully. The index weight is calculated by using the entropy weight method. Then, the certainty degree of each index belonging to the corresponding cloud is obtained by using the cloud model. The final risk level of debris flow is determined according to the synthetic certainty degree. The conclusions are drawn that the method is feasible and accurate rate of risk estimation for debris flow is very high, so a new method and thoughts for the risk assessment of debris flow can be provided in the future.


Author(s):  
Ruben Van Coile ◽  
Robby Caspeele ◽  
Luc Taerwe

<p>Concrete insulation properties and chemo-physical stability up to 400-500°C generally prevents concrete structures from collapsing in fire. Consequently, the safety assessment of reinforced concrete members – and specifically columns – is a must past any severe fire. This post-fire assessment should be based on reliability considerations, as many uncertainties are associated with both the fire evolution and the residual mechanical properties of the materials. The reliability considerations should clarify whether the column has an adequate safety level for its intended post-fire use. An easy-to-use reliability-based assessment method is presented in this paper to determine the bearing capacity of a reinforce concrete column after a fire, and the safety performance of the method is investigated. The proposed method is shown to be at the same time easy to use and very reliable.</p>


2019 ◽  
Vol 11 (3) ◽  
pp. 877-890
Author(s):  
Rongrong Wan ◽  
Peng Wang ◽  
Xue Dai ◽  
Zheng He

Abstract The drastic changes in water regime are of great importance for maintaining water security in lakes with violent seasonal fluctuations. Based on hydrological data of Dongting Lake, the second largest freshwater lake in China, during 1980–2014, a set of water safety assessment methods suitable for seasonal lakes was constructed. Results demonstrated the following. (1) The year 2003 was a major time point for changes in water regime in Dongting Lake between 1980 and 2014. (2) The water regime changes in different parts of Dongting Lake exhibited certain similarities in periodicity and overall change trends. Among them, South Dongting Lake presented the best water security status, followed by East Dongting Lake and West Dongting Lake. (3) Compared with 1980–2002, the complexity of the water safety level change in East Dongting Lake increased in 2003–2014, as manifested in the tendency of the distribution of water safety levels to change sharply. (4) The influence of dry years on the water safety of Dongting Lake was greater than that of rainy years. The multi-time, multi-scale and multi-target lake water safety assessment method based on water regimes provides new ideas and methods for global research on seasonal lake water safety.


2018 ◽  
Vol 5 (7) ◽  
pp. 180212 ◽  
Author(s):  
Qingwei Xu ◽  
Kaili Xu ◽  
Li Li ◽  
Xiwen Yao

Safe production is the foundation of the normal operations of petrochemical enterprises, and it helps maintain social stability. The main purpose of this study is to prevent petrochemical enterprise accidents by proposing a composite safety assessment approach based on the cloud model, preliminary hazard analysis–layer of protection analysis (PHA–LOPA) and the bow-tie model. First, the petrochemical enterprise and its relevant indicators were evaluated based on the cloud model. Second, the quantitative effect of the uncertainty transformation on the evaluation result of the cloud model was further analysed. This mainly includes the error analysis of the numerical characteristics under the conditions of few samples and small values. Third, the critical indicators such as shock and noise can be weakened and prevented by corresponding safety measures based on PHA–LOPA and the bow-tie model. After adopting two independent protection layers, the risk levels of shock and noise decrease from 3 to 2. Then, shock and noise were analysed in depth with the bow-tie model, and the causes and consequences were identified. Moreover, corresponding safety measures were taken to prevent accidents. The case study validated the validity and feasibility of the composite safety assessment approach proposed here.


2018 ◽  
Vol 38 ◽  
pp. 03016
Author(s):  
Zhen Yu Hu ◽  
Shui Bo Zhang ◽  
Xin Yan Liu

In order to select the optimal quasi-bidding project for an investment enterprise, a bidding decision-making model for international PPP projects was established in this paper. Firstly, the literature frequency statistics method was adopted to screen out the bidding decision-making indexes, and accordingly the bidding decision-making index system for international PPP projects was constructed. Then, the group decision-making characteristic root method, the entropy weight method, and the optimization model based on least square method were used to set the decision-making index weights. The optimal quasi-bidding project was thus determined by calculating the consistent effect measure of each decision-making index value and the comprehensive effect measure of each quasi-bidding project. Finally, the bidding decision-making model for international PPP projects was further illustrated by a hypothetical case. This model can effectively serve as a theoretical foundation and technical support for the bidding decision-making of international PPP projects.


2019 ◽  
Vol 19 (8) ◽  
pp. 2517-2532 ◽  
Author(s):  
Xianfeng Huang ◽  
Wanyu Li ◽  
Yingqin Chen ◽  
Guohua Fang ◽  
Wei Yan

Abstract The utilization of floodwater resources will produce benefits, but it will also pose risks; therefore, it is necessary to strengthen knowledge regarding risk assessment to minimize negative effects. In the present study, the risk factors for the utilization of floodwater resources in water diversion projects were identified, the index system was constructed, and the fuzziness and randomness of the risk were considered. Assessment was performed with respect to the following three projects: water storage, water conveyance, and water pumping. The specific methods to improve the cloud model are as follows: analytic hierarchy process (AHP) is used to calculate subjective weights, entropy weight method and projection pursuit method are used to calculate objective weights, X-conditional cloud is used to calculate index membership degree, and finally combination weight and membership degree are combined to obtain the risk level of flood resource utilization. The above methodology was applied to the risk assessment of floodwater resources utilization in the Jiangsu Province of the East Route of the South-to-North Water Transfer Project. The risk of floodwater resources utilization in high-flow, normal-flow, and low-flow years was evaluated, and the validity and applicability of the assessment method were verified.


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