Grid-integrated wind-solar and hydrogen storage coupling power generation systems face problems such as high costs of investment, construction, operation, and maintenance. After the conformity of renewable energy, the system’s dependability decreases, and the comprehensive power fluctuation influences the power grid greatly. To solve the above problems, this paper proposes a two-tier model. With the system economy, reliability, and wind-solar comprehensive power fluctuation suppression as optimization objectives, the capacity distribution of the hydrogen storage devices can be optimized. Based on a practical microgrid example, the inner and outer layers adopt Sparrow Search Algorithm (SSA) and Multi-objective Optimization Particle Swarm Optimization Algorithm (MOPSO), respectively, to solve the established model. The optimization results are compared according to three scenarios. The results demonstrate that this model can enhance the operational reliability of the system while considering the overall economy of the system and effectively suppressing the fluctuation of solar and wind power.

The shipping volume in inland waterways has been rapidly increasing in recent years. However, it is still challenging to trace oil spills caused by maritime accidents. In this study, the oil spill dispersion trajectory in inland rivers was obtained by simulating the trajectory of oil particles under different waterway conditions based on a simulated flow field. Firstly, the flow field was simulated using a volume of fluid (VOF) model and the solution of an open-channel equation. Then, an oil particle diffusion and drift model was established using Python to simulate the diffusion of the oil. Finally, eight oil spill simulation scenarios were conducted with different channel shapes and cross-sections. The results showed that oil spills spread more extensively in a curved channel with a trapezoidal cross-section compared to other channel shapes and cross-sections. The findings of this research could be used to guide inland river environmental protection and oil spill trajectory tracking.

The increasingly busy maritime traffic system has resulted in frequent maritime accidents. To prevent maritime accidents, we investigated and studied typical cases of maritime accidents along the coast of China in recent years. Based on the complex network theory, a network model of China's coastal maritime traffic accidents is constructed from the four risk factors of human-ship-environmental-management. On this basis, the overall structural characteristics of the maritime accident network are analyzed according to the characteristic parameters of the complex network. In addition, based on the node betweenness and PageRank value, the network robustness analysis is carried out, the key factors in the maritime accidents are excavated and risk prevention and control measures are proposed. The research shows that the average path length of the marine traffic accident network is short, the clustering coefficient is high, and the risk spreads quickly in the network and passes through fewer nodes, which can lead to the occurrence of accidents. Through the management and control of key risk factors, the evolution of risks can be effectively blocked and the large and above maritime accidents can be reduced.

The demands of passing through dams are on the raise with increasing in the number of LNG fueled-vessels recently. Ship elevators that is a convenient means to pass through high-dam navigable waters play an important role, however, when the LNG fueled-vessels pass through the ship elevator, there are high risks of combustion caused by LNG fuel leak, and even leading to explosion due to the semi-closed structure of ship elevators, which hazard people's lives, and structures. In this study, the largest ship elevator worldwide located at the Three Gorges is chosen as the research object. A quantitative method of assessing the combustion and explosion hazards to the people and structure from LNG fuel leak accidents inside ship elevator is proposed, and the numerical simulations of three typical LNG leak accidents are carried out based on the heat transmission mechanism of LNG liquid-phase leaks on water surfaces constructed in our paper, finally, corresponding hazard mitigation measures are proposed according to analysis results and their validity is proved. Our work discloses the hazard level of fuel leak accidents when an LNG fueled-vessel passes the ship elevator, and provides theoretical references to risk decision-making and risk management of LNG fueled-vessels passing ship elevators.

As a clean and efficient new maritime fuel, the strict emission standards worldwide recently have been stimulating the use of Liquefied nature gas (LNG), leading a great increase in the number of LNG-fuelled ship. Due to the hazard characteristics of freezing and flammability after release inside a ship lock, it may cause fire and explosion consequence which may threaten the safety of people and lock structure, the research on quantitative risk assessment (QRA) of fuel leakage during lockage is urgently needed in the safety management of LNG-powered ship and ship lock. This paper proposes an integrated QRA model for analysing the fuel leakage risk during lockage of LNG-fuelled ship, and the QRA process based on the world's largest lock Three Gorges lock is performed including the risk identification, probability calculation and consequence modelling. The results show that the individual risks (IRs) of LNG-fuelled ship during lockage is within the negligible area, and the main threat of LNG leakage is heat radiation rather than overpressure. The research results of the study can provide theoretical support in policy-making process of LNG-fuelled ship and ship lock.

Ship path planning is crucial for the shipping industry, especially for the development of autonomous ships. Many algorithms have been developed over the last few decades to solve the ship path planning problem. However, it is still challenging for ship path planning in an inland waterway. In this paper, an improved RRT algorithm for ship path planning in complex inland waterways is proposed. The improved algorithm has a path shearing and smoothing module, and the function of keeping a safe distance between a moving ship and obstacles. In addition, the algorithm has been tested in two inland waterway scenarios, and the results have confirmed its feasibility and reliability. The path planning algorithm proposed in this research seeks to reduce the risks faced by ship navigation in inland water. It has theoretical and practical significance in improving navigation safety in complex inland waters.

Navigation tunnels are an essential part of inland shipping networks and play a vital role in enhancing the efficiency of navigation. Ships require a significant amount of time to pass through a navigation tunnel owing to safety speed limitations. If a ship fire accident happens in a confined space inside a navigation tunnel, people on board the ship cannot evacuate quickly on account of the high freeboard of the ship. The accumulated fire smoke poses a significant risk to human lives and can even be fatal. Currently, research on navigation tunnels are rather few, none of them has discussed the safety evacuation under ship fire scenarios. In this study, the Gou Pitan navigation tunnel is used as an example, the safety assessment of evacuation is realized by the simulation and calculation of safety egress time, then, a general method to quantitatively assess the safety of evacuation during ship fire accidents in navigation tunnels is proposed based on the analysis results. This study fills the gaps in the relevant research, and the assessment results can be used to develop the ventilation strategies during emergency evacuations, furthermore, provide a theoretical reference for the safe operation of navigation tunnels.

The causes of maritime accidents are complex, mostly due to the coupling of four types of factors: human-ship-environmental-management. To effectively analyze the causes of maritime accidents in China, and reveal the risk coupling characteristics of accidents, this paper establishes the N-K model of maritime accident, and calculates and analyzes the four types of coupling of risk factors affecting safety in maritime traffic. This paper collects 922 maritime accidents that occurred in China from 2000 to 2020, and analyzes the location, type, and level of accidents and uses the trigger principle to describe the process of accidents. For marine and inland river accidents, this paper calculates the four types of coupling values of risk factors (single-factor coupling, two-factor coupling, three-factor coupling, four-factor coupling) for comparison and analysis. In addition, this paper calculates the coupling values of six typical maritime accidents of collision, sinking, contact, fire/explosion, stranding, grounding. According to the coupling values and the frequency of sub-factors, this paper analyzes the coupling characteristics of maritime accidents. The results show that in maritime accidents, as the number of risk factors participating in the coupling increases, the coupling value increases, and the multi-factor coupling is more likely to cause accidents. The overall situation of risk coupling causes of maritime accidents is basically consistent with inland river accidents, but they have their own characteristics in the specific degree of risk coupling and the dominant risk elements. In different types of maritime accidents, the risk coupling has different characteristics, and the dominant risk factors are also different.

In this study, a battery thermal management (BTM) system immersed in a silicone sealant (SS) is designed for an 18650-type lithium-ion power battery. When compared with a general water-cooled BTM system, the novel BTM system with a simple structure can provide effective heat dissipation and long-term corrosion protection. The thermal performance of the three battery modules prepared using SS packaging are analyzed in detail, including an air-cooled battery module, a pure SS battery module, and an SS/BN module composited with 10 wt% BN (SS/BN). The charge and discharge measurements are carried out under various conditions such as the natural air cooling, forced ventilation cooling, and immersion cooling methods. The experimental results indicate that the immersion SS/BN system can significantly reduce the maximum temperature of the battery module and balance the temperature in the module at different discharge rates. The maximum temperature of the three immersion SS modules is less than 35 degrees C during the 3C discharge process. Moreover, the temperature difference of the immersion SS/BN module can be maintained within 0.5 degrees C. This research can provide insights into the design and optimization of BTM systems, especially under water or moisture conditions.

With the rapid development of the inland shipping in recent years, the risk of wharf pollution from ship is increasing. Thus, it is necessary to make a scientific assessment on ship pollution risk. This paper proposes a risk assessment according to the ship pollution at regional port by using a typical petrochemical wharf in Wuhan section of Yangtze River main line as an example, carries out a comprehensive evaluation from the aspects of risk identification, risk probability and risk level calculation, and pollution consequence prediction. The results of the wharf risk assessment are important for the development of the ship pollution risk counterplans.

Determination of the appropriate following distance between ships is essential for their safe passage through navigation tunnels. In this study, it uses the following theory of traffic flow to establish a model that enables the calculation of the following distance between ships in a navigation tunnel. Based on the proposed model, the study also introduces an approach to calculate and control the following distance at different risk levels in order to control the passage intervals within a navigation tunnel. In addition, the study tests the model using data for the second line navigation tunnel of the Silin Junction in the Wujiang River, China and compare the results with existing distance control parameters for ships in the Goupitan first line navigation tunnel in the Wujiang River. The proposed model can effectively reduce the risk of ship navigation in tunnels by providing reference information for safe ship navigation, thus allowing operational and management staff to ensure adherence to safety procedures within the navigation tunnel.

新工科的建设与发展内容之一就是需要对课程教学评价进行改革.本文以电路基础课程为例构建面向教学全过程的整体动态发展性评估方法.基于电路基础课程各部分衔接性和时序性强的特点,首先建立面向新工科的电路基础课程的综合评估指标体系,然后有效集成课前、课中、课后各类教学活动实现多维、动态、全面、智能的教学综合评价,从而对学生的能力全面发展有较确切的定量分析和判断,探索出提高新工科时代的教学质量的新途径.

Oil lightering is the process of transferring crude oil or oil products between vessels of different sizes, usually between a barge and a bulker or oil tanker. This economic and convenient operating method develops quickly in coastal areas recently, which greatly relieves the contradictory situation between the overlarge tendency of oil tanker with the limited natural conditions of some ports. Whereas, it`s also deemed to be a high pollution risk process, once oil spill occurs, nearby environment of the port tremendously suffering consequently. This paper selects the Qinzhou port, which has the largest oil lightering quantities per year as a study area, calculating the spill probability during the lightering process. Through conducting numerical simulations under different lightering situations, the oil trajectory is obtained, and the pollution area and affecting degree are visually and quantitatively analyzed. So, some precautionary measures are forwarded to minimize the spill probability and lower the impact on the environment during oil lightering process.

In the present study, formal safety assessment (FSA) is introduced to investigate lockage safety of LNG-fueled ships. Risk sources during lockage of LNG-fueled ships in four typical scenarios, namely, navigation between two dams, lockage, anchorage, and fueling, are identified, and studied in combination with fundamental leakage probabilities of various components of LNG storage tanks, and simulation results of accident consequences. Some suggestions for lockage safety management of LNG-fueled ships are then proposed. The present research results have certain practical significance for promoting applications of LNG-fueled ships along Chuanjiang River and in Three Gorges Reservoir Region.

This paper presents a method based on the oceanic current model and the oil spill model to evaluate the pollution risk of sensitive resources when oil spills occur. Moreover, this study proposes a novel impact index based on the risk theory to improve the risk assessment accuracy. The impact probability and the first impact time of the oil spill are calculated through a stochastic numerical simulation. The risk assessment content is enriched by establishing an impact model that considers the impact of sensitive index and spillage. Finally, the risk score of sensitive resources in an oil spill accident is visualized for formulating a scientific and effective protection priority order in a contamination response strategy. This study focuses on integrating every possible impact factor that plays a role in risk assessment and helps to provide a better theoretical support for protecting sensitive resources.

With the fast development of shipping industry,pollution threat from ships as mobile sources of pollution have been increased urgently.The major pollution is ship sewage,which is more frequent.In order to manage inland watership pollutantsdischarge,an on-line monitoring system for inland water ship sewage discharge has been designed,which based on the AIS and ENC device,sense and software platform.As to test the performance of this system,it was been fitted on a real ship and the prototype test was carried out.The research shows that this system can monitor ship sewage discharge information,recordrelevant datum,alarm the corresponding situation,and send the information to administrative authorities to help them realize effective regulation.

Ship navigation simulation is a hot topic in recent years, of which the simulation of Three-Dimension environment field is a key problem. Different from traditional method, this paper focuses its emphasis on how to get a real marine environment. Depending on the single air, sea, wave numerical model, this paper develops a Union Environment Dynamical Forecast System (UEDFS) based on large-scale distributed scientific computing, by which the marine environment can be detail simulated. Through the experiment of a real case, the performance of UEDPS is proved that it can provide a high precise and harmonious environment field. At the same time, the simulated datum of wind, current and wave can be introduced into calculating the ship motion in this marine environment. Virtual reality technology is used to create the three dimension sea scene by VC and OpenGL and it has taken a good result.

《电工学》是一门非电专业的专业基础课程,双语教学的提出与实施是改变传统教育体系,确立新的科学教育目标的重要举措。而将多媒体技术应用于《电工学》双语教学实践,在教学中取得了良好的效果。