Risk Coupling Characteristics of Maritime Accidents in Chinese Inland and Coastal Waters Based on N-K Model

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.

Plant Traits of Phalaris Arundinacea and Phragmites Australis – Examining Effects of Water Level, Salinity, and Soil Types in a Mesocosm Experiment

Knowledge about the distribution of species along rivers and estuaries is the basis for decisions in nature conservation, but also for nature-based coastal and shore protection. Along rivers and estuaries, abiotic conditions affect plant traits, especially close to the marsh edge, and thus determine the distribution of plant species. Phragmites australis and Phalaris arundinacea occur along the German Elbe in the inland river and in the estuary, but the distribution of both species is locally and regionally inhomogeneous. We therefore simulated abiotic conditions of respective Elbe sections in a mesocosm experiment and investigated the influence of soil type, salinity, water level, and plant provenance on plant traits of P. australis and P. arundinacea. We compared growth-related and mechanical plant traits of both species. Productivity of P. arundinacea was less affected by sandy soil than that of P. australis. P. australis was insensitive to salinity and water level fluctuations, while traits of P. arundinacea responded to these factors. Furthermore, mechanical properties within a species were mainly dependent on plant growth. P. arundinacea was more flexible than P. australis, which can be attributed to morphological differences and differences in plant tissue. Plant provenance did not affect the response of plant traits to abiotic conditions. Our study provides clues for understanding the distribution patterns of P. australis and P. arundinacea.

Comparison of Inland Ship Emission Results from a Real-World Test and an AIS-Based Model

Inland shipping is pivotal to the comprehensive transport system of China. However, ship emission has become a major air polluter in inland river regions, and relevant emission inventories are urgently needed. Currently, the Automatic identification System based (AIS-based)emission model is widely used in calculating the ocean-going ship emission inventory. However, due to the lack of AIS data in the river area, the inland ship emission inventory mainly uses the fuel consumption method. With the continuous improvement of AIS data quality in the river area, the AIS-based emission model can be adopted in the development of inland ship emission inventory. However, there are few studies on the evaluation of the accuracy of the inland ship emissions using the AIS-based emission model. This study makes a comparison between test data and model-calculated data to evaluate the accuracy of the AIS-based emission models. Inland ship activities are divided into being at berth, maneuvering (port departure and port arrival), and on cruise modes in an AIS-based emission model. The model-calculated CO2, HC, and NOx emission rates can cover those onboard emission test data, but the values from the model are much lower. The total average ratios of test data to model-calculated data for CO2, CO, HC, and NOx are 2.66, 19.12, 2.46, and 3.16 when engine loads are below 60%. In upstream cruise mode, average emission rates of CO2, CO, HC, and NOx from the real-world test are 1.91–6.48, 8.78–27.83, 3.05–8.96, and 4.06–5.96 times higher than those from the AIS-based model, respectively. However, those are only 1.08–1.51, 6.74–9.67, 2.03–3.75, and 1.65–2.75 times higher than those from the AIS-based model in downstream cruise mode.

Diagnosis of Key Ecological Problems and Layout of Ecological Restoration Projects- A Case Study of the Aksu River Basin, China

The sustainable development of ecological environments is the basis of the sustainable development of inland river basins in arid areas with fragile ecological environments. The aim of our study is to diagnose the ecological problems of the Aksu River basin (ARB) and explore the ecological security pattern (ESP) and the layout and implementation path of ecological protection projects for mountains, rivers, forests, farmland, lakes, grasslands and deserts (MRFFLGD) in arid areas under different security levels. The Aksu River, the largest source of the Tarim River, was selected as the case study. The equivalent factor evaluation method (EFEM) was used to estimate the ecological service value (ESV), and the InVEST model was employed to quantify the ecological function indicators. By constructing the richness index, the ESV of the study area was measured spatially, and the ecological problems in the ARB were identified and diagnosed. Using cold/hot spot detection analysis and the minimum cumulative resistance (MCR) model, the ESPs at three security levels were constructed. The layout of ecological protection measures and the implementation path for MRFFLGD were studied. The results showed that the ESV of ARB showed an upwards trend from 1990 to 2018, and the three services of water conservation, waste treatment and soil formation and retention grew fastest. The value of ecosystem services in the study area in 2018 ranged from 5,390 yuan to 131,080 yuan/hm2. The high-value areas were mainly located in the oasis and the northern mountainous area, and the low-value areas were mainly located in the desert area. The ecological source areas of high, medium and low safety levels were 1806.3 km2, 3416.8 km2 and 4804.32 km2, respectively. Based on the spatial distribution of ESV in the ARB and the preliminary diagnosis of the basic ecological problems in the study area, three kinds of ecological protection engineering models, namely, conservation, natural restoration and assisted regeneration, were proposed for the four types of ecological protection zones. To provide a decision-making basis for ecological environmental management and regional sustainable development in the ARB, the optimization patterns of points (6 key ecological protection projects), lines (ecological corridors) and polygons (ecological source areas) were constructed. The results of this study can also serve as a reference for ecological environmental protection in other arid inland river basins.

Design and Analysis of Ship Exhaust Boiler Flue Cleaning System Based on Computer

In recent years, the country for ship emissions of exhaust gas control is relatively loose, but also relatively lack of specific and effective supervision and scientific exhaust emissions and treatment technology, so China’s air pollution is increasingly serious. With the implementation of regulations on the emission of air pollutants from land-based sources such as motor vehicles and power stations, researchers have found that exhaust pollution from ships accounts for an increasing proportion of the overall air pollution, especially in port cities and coastal areas, causing great damage. In order to effectively reduce ship exhaust pollution in China, the Ministry of Transport through the establishment of ship emission control area program, stage by stage and regional limits on the sulfur content of fuel used by ships sailing in China’s ports and coastal inland river waters. Through the implementation of the regulations of the ship discharge control area, all kinds of pollutants discharged by ships have been significantly reduced, and the environment of the port area has been improved to a certain extent. At the same time, it is also necessary to use the computer and other high-tech constantly develop new ship exhaust cleaning mode to deal with the increasingly serious environmental pollution problem.