Quantitative Risk Assessment and Management of Hydrogen Leaks from Offshore Rocket Launching Platforms

Liquid hydrogen in cryogenic condition can incidentally leak from offshore rocket launching platforms, leading to catastrophic impacts. Risk assessment and management of hydrogen leaks are required to prevent such accidents. The aim of the paper is to develop a methodology for quantitative risk assessment on hydrogen leak hazards from offshore rocket launching platforms during their filling process. A set of credible leak scenarios are chosen using Latin Hypercube Sampling (LHS) technique. The flows of hydrogen leaks for the selected scenarios are simulated using Computational Fluid Dynamics (CFD) method. A probabilistic model for predicting hydrogen leaks is established based on the computed results, where a long short-term memory (LSTM) network is used. Individual risks are defined as likelihood of explosion and fire due to hydrogen leaks. As an illustrative example, the developed methodology was applied to a hypothetical offshore rocket launching platform, confirming that the hydrogen leak risk level of the platform meets the ALARP (As Low As Reasonably Practicable) criteria. Risk mitigation options are also discussed to reduce the risk level

Endophytic Colletotrichum species from Dendrobium spp. in China and Northern Thailand

Species of Colletotrichum are commonly found in many plant hosts as pathogens, endophytes and occasionally saprobes. Twenty-two Colletotrichum strains were isolated from three Dendrobium species – D. cariniferum, D. catenatum and D. harveyanum, as well as three unidentified species. The taxa were identified using morphological characterisation and phylogenetic analyses of ITS, GAPDH, ACT and ß–tubulin sequence data. This is the first time to identify endophytic fungi from Dendrobium orchids using the above method. The known species, Colletotrichum boninense, C. camelliae-japonicae, C. fructicola, C. jiangxiense and C. orchidophilum were identified as fungal endophytes of Dendrobium spp., along with the new species, C. cariniferi, C. chiangraiense, C. doitungense, C. parallelophorum and C. watphraense, which are introduced in this paper. One strain is recorded as an unidentified species. Corn meal agar is recommended as a good sporulation medium for Colletotrichum species. This is the first report of fungal endophytes associated with Dendrobium cariniferum and D. harveyanum. Colletotrichum camelliae-japonicae, C. jiangxiense, and C. orchidophilum are new host records for Thailand

Corrigendum: Hu H et al. (2023) Taxonomic and phylogenetic characterisations of six species of Pleosporales (in Didymosphaeriaceae, Roussoellaceae and Nigrogranaceae) from China. MycoKeys 100: 123–151. https://doi.org/10.3897/mycokeys.100.109423

Four new species, Xynobius azonius sp. nov., X. brevifemora sp. nov., X. duoferus sp. nov., and X. stipitoides sp. nov., are described and illustrated, and one species X. geniculatus (Thomson, 1895) is newly reported from South Korea. Xynobius geniculatus (Thomson, 1895) is redescribed and illustrated, and a new combination, Xynobius (Stigmatopoea) cubitalis (Fischer, 1959), comb. nov. is suggested. An identification key to the Xynobius species known from South Korea is provided

Taxonomic and phylogenetic characterisations of six species of Pleosporales (in Didymosphaeriaceae, Roussoellaceae and Nigrogranaceae) from China

Pleosporales comprise a diverse group of fungi with a global distribution and significant ecological importance. A survey on Pleosporales (in Didymosphaeriaceae, Roussoellaceae and Nigrogranaceae) in Guizhou Province, China, was conducted. Specimens were identified, based on morphological characteristics and phylogenetic analyses using a dataset composed of ITS, LSU, SSU, tef1 and rpb2 loci. Maximum Likelihood (ML) and Bayesian analyses were performed. As a result, three new species (Neokalmusia karka, Nigrograna schinifolium and N. trachycarpus) have been discovered, along with two new records for China (Roussoella neopustulans and R. doimaesalongensis) and a known species (Roussoella pseudohysterioides). Morphologically similar species and phylogenetically close taxa are compared and discussed. This study provides detailed information and descriptions of all newly-identified taxa

Equipment Layout Optimization Based on Human Reliability Analysis of Cabin Environment

There are many factors involved in the layout optimization of cabin equipment, and human factors should be considered in the early stage of layout design. Human reliability is an effective index to evaluate the probability of success of the human completion of tasks. In order to put forward the method of human reliability which is more suitable for the layout optimization of cabin equipment, the existing methods of human reliability analysis (HRA) are systematically studied. At the same time, taking HRA, equipment correlation and cabin balance as objective functions, the optimization problem of cabin equipment layout was quantified into a mathematical model. When solving the model, the visibility graph method was used to model the cabin path planning, and a solution platform for the optimization of cabin equipment layout was developed on the basis of a genetic algorithm. Finally, the developed platform was applied with a ship example, and the results before and after the layout optimization were displayed through a three-dimensional model. At the same time, equipment layout evaluation software was used to simulate the experimental results so as to compare the improvement of important parameters before and after the layout optimization

Review of condition-based maintenance strategies for offshore wind energy

The existing maintenance strategies of offshore wind energy are reviewed including the specific aspects of condition-based maintenance, focusing on three primary phases, namely, condition monitoring, fault diagnosis and prognosis, and maintenance optimization. Relevant academic research and industrial applications are identified and summarized. The state of art, capabilities, and constraints of condition-based maintenance are analyzed. The presented research demonstrates that the intelligent-based approach has become a promising solution for condition recognition, and an integrated data platform for offshore wind farms is significant to optimize the maintenance activities.info:eu-repo/semantics/publishedVersio

Condition-Based Maintenance for Offshore Wind Turbines Based on Support Vector Machine

A condition-based maintenance policy for offshore wind turbines is presented in consideration of the maintenance uncertainty and the weather effect. In this paper, the offshore wind turbine is divided into four main assemblies—namely, the rotor, gearbox, generator, and pitch system. The support vector machine classification technique is implemented to analyze the failure information, which was collected from field data in China. According to the results of fault diagnosis and prediction, the assembly that reaches the corresponding maintenance threshold will be repaired. At the same time, a maintenance opportunity occurs for the rest of the components, and an optimized plan can be determined by arranging the maintenance combination and time. The calculated results indicate that the proposed condition-based maintenance policy is beneficial to reduce the maintenance expenditure of offshore wind turbines

Fire Risk Assessment of a Ship’s Power System under the Conditions of an Engine Room Fire

This paper presents a risk assessment method for a ship’s power system under the conditions of an engine room fire based on the expert comprehensive evaluation (ECE) method combined with the fuzzy fault tree analysis (FFTA) method. The composition of the main engine system in the engine room and the failure logic of each subsystem were analyzed, and the fuzzy fault tree of a ship engine room fire was constructed. The probability of system failure and the importance of basic events were calculated. The fire safety risk assessment model was established using the safety risk matrix. The risk assessment of a ship engine room fire was implemented. The results demonstrated that the fire frequency of the ship engine room was 5.232 × 10−6 h−1. The fire risk of the main engine fuel system was the highest. Fuel leakages from diesel supply tanks and heavy fuel oil tanks are the main cause of accidents. The proposed method eliminated the influence of incomplete statistics in the risk assessment process and improved the accuracy and credibility of the reassessment results

Risk Identification of FPSO Oil and Gas Processing System Based on an Improved FMEA Approach

It is increasingly necessary to perform risk analysis in marine structures, to ensure system safety, as they are large and complex. In view of the shortcomings of failure mode and effect analysis (FMEA), a modified fuzzy TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) approach is proposed that is based on fuzzy evidence reasoning (FER), and considers the risk factor rating and relative weight. The presented method is used to prioritize the risk of equipment failure modes for the floating production storage and offloading system (FPSO) oil and gas processing system. The subjective weights and objective weights of occurrence (O), severity (S), and detectability (D) have been considered comprehensively. The subjective experience of the experts and the objective information reflected by the O, S, and D ratings are all included in the weights, making the ranking results closer to reality. The results can be scientific references for decision-makers in risk identification

Risk Identification of FPSO Oil and Gas Processing System Based on an Improved FMEA Approach

It is increasingly necessary to perform risk analysis in marine structures, to ensure system safety, as they are large and complex. In view of the shortcomings of failure mode and effect analysis (FMEA), a modified fuzzy TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) approach is proposed that is based on fuzzy evidence reasoning (FER), and considers the risk factor rating and relative weight. The presented method is used to prioritize the risk of equipment failure modes for the floating production storage and offloading system (FPSO) oil and gas processing system. The subjective weights and objective weights of occurrence (O), severity (S), and detectability (D) have been considered comprehensively. The subjective experience of the experts and the objective information reflected by the O, S, and D ratings are all included in the weights, making the ranking results closer to reality. The results can be scientific references for decision-makers in risk identification