Evaluation of the geoecological and fire situation in case of the oil spillage on the water surface

The work provides an assessment of the geoecological situation during an oil spill on the water surface. The modeling of the process of oil burning on the water surface is carried out, and also a model for estimating the oil burning time during depressurization of the underwater passage of the main oil pipeline is proposed. The assessment of individual and social risk in case of ignition of an oil spill as a result of depressurization of the underwater crossing of the main oil pipeline is given. The fire risk assessment was carried out under the condition of a guillotine rupture of the underwater pipeline, since, despite the lowest frequency of this type of depressurization, the levels of exposure to damaging factors, due to the largest volume of oil spills, will be maximum and will make the main contribution to the magnitude of the fire risk. When forecasting an emergency, a model of the spread of an oil slick along the water surface of a watercourse was developed, which takes into account the wind speed and the speed of the river flow.

Evaluation of the geoecological and fire situation in case of the oil spillage on the water surface

The work provides an assessment of the geoecological situation during an oil spill on the water surface. The modeling of the process of oil burning on the water surface is carried out, and also a model for estimating the oil burning time during depressurization of the underwater passage of the main oil pipeline is proposed. The assessment of individual and social risk in case of ignition of an oil spill as a result of depressurization of the underwater crossing of the main oil pipeline is given. The fire risk assessment was carried out under the condition of a guillotine rupture of the underwater pipeline, since, despite the lowest frequency of this type of depressurization, the levels of exposure to damaging factors, due to the largest volume of oil spills, will be maximum and will make the main contribution to the magnitude of the fire risk. When forecasting an emergency, a model of the spread of an oil slick along the water surface of a watercourse was developed, which takes into account the wind speed and the speed of the river flow.

A Recent Progress in Performance and Property Improvement in Underwater Welding

Underwater welding is the process of connecting materials underwater in the presence of water. It is used to maintain and improve the structure in marine and offshore applications. It's utilized for underwater pipeline maintenance, submerged offshore oil drilling, and ship repairs. It can also be found in nuclear power plants and deep-sea mining. Underwater welding is divided into two categories dry welding and wet welding. Dry welding entails enclosing the weld zone in a hyperbaric tank filled with a gas mixture and welding at the prevailing pressure. Wet welding is a type of welding that uses waterproof electrodes and is done directly on the component to be welded. The major benefit of this welding is its simplicity and cost effectiveness, but we can't obtain high weld quality as easily as we can with dry welding. Dry welding, on the other hand, may provide high weld quality, but it is a time-consuming procedure that needs the welder to secure the region with the hyperbaric vessel, and it is also a costly method. Underwater welding has a number of issues, including bubble arc generation, cold cracking, microstructural deformation, and more. We attempted to bring together the most recent developments in the field of underwater welding. We've outlined several techniques that were used to improve welding characteristics as well as important issues that must be addressed. This review article may be used to figure out what measures need to be taken to enhance the underwater weld joint quality. Keywords: Underwater welding, underwater wet welding, underwater dry welding, hyperbaric vessel, underwater welding development

Zero-Shot Pipeline Detection for Sub-Bottom Profiler Data Based on Imaging Principles

With the increasing number of underwater pipeline investigation activities, the research on automatic pipeline detection is of great significance. At this stage, object detection algorithms based on Deep Learning (DL) are widely used due to their abilities to deal with various complex scenarios. However, DL algorithms require massive representative samples, which are difficult to obtain for pipeline detection with sub-bottom profiler (SBP) data. In this paper, a zero-shot pipeline detection method is proposed. First, an efficient sample synthesis method based on SBP imaging principles is proposed to generate samples. Then, the generated samples are used to train the YOLOv5s network and a pipeline detection strategy is developed to meet the real-time requirements. Finally, the trained model is tested with the measured data. In the experiment, the trained model achieved a [email protected] of 0.962, and the mean deviation of the predicted pipeline position is 0.23 pixels with a standard deviation of 1.94 pixels in the horizontal direction and 0.34 pixels with a standard deviation of 2.69 pixels in the vertical direction. In addition, the object detection speed also met the real-time requirements. The above results show that the proposed method has the potential to completely replace the manual interpretation and has very high application value.

Assessment of the quality of control of the ship “crosshair” under wind load conditions

There are few ports in the Far North. Therefore, it is not difficult to assume that most of the cargo operations in the future will be implemented in the open part of the sea space of the Arctic regions. In this regard, the safe maneuvering of a tanker at the offshore oil terminal when carrying out cargo operations with hydrocarbon raw materials is one of the most important and urgent tasks. When performing this type of operation, the main threat to environmental safety is a rupture of the cargo line hose and damage to the underwater pipeline due to the tanker piling up on the oil terminal. Therefore, the improvement of the methods of controlling the movement of the tanker during its positioning at the oil terminal in the process of carrying out the operation of loading oil is significant. Improving tanker control technologies can contribute to improving the quality of control, reducing the likelihood of emergencies, and, as a result, increasing the safety of cargo operations when transshipping oil products in the open sea.

Physical model experiment on the influence of water depth on the underwater pipeline surface impacted by landslide surge

A physical model experiment of flume block landslide was used to study the influence of landslide surge impact on underwater pipeline surface under different water depths. The influence of surge impact pressure on pipelines with different water depths and the impact pressure of surge at different angles of underwater pipelines wall were analyzed. And the relationship between the maximum impact pressure of underwater pipelines and the depth of water was obtained. The results indicated that with the decrease of the water depths, the maximum impact pressure at the wall of the underwater pipeline increases approximately linearly, and the slider is easier to form higher first wave height. The maximum impact pressure of the upper surface of the pipeline wall is greater than that of the lower surface of the pipeline wall under the same working conditions. It is also found that the smaller the depth of water, the larger the maximum pressure and average pressure at the measuring point would be and the greater the pressure fluctuation becomes when slider volume and landslide water inlet angle and speed remain the same.

Hydrochemical state of the Uglovoy Bight (Amur Bay) in different seasons

Hydrological and chemical surveys were conducted in the Uglovoy Bight in October, 2019, February, May and June, 2020 (in total 120 stations) and chemical analyses of water from 13 small rivers running into the bight were done on October 21-22, 2020. Extremely high concentration of nutrients was detected in the Peschanka, Saperka and Gryaznukha Rivers that was obviously caused by waste waters discharge. These rivers were the main source of the bight eutrophication. Within the bight, the highest anomalies of chemical parameters, as low oxygen content, low pH, high concentrations of nutrients (N, P, Si), high turbidity, and high CO2 partial pressure were observed close to these rivers mouths, in particular under the ice in winter, when wind mixing was absent. The hypoxia disappeared in the warm period of year because of wind mixing. High concentrations of total nitrogen (10.0-40.0 μmol/L), total phosphorus (1.5-2.0 gmol/L), dissolved organic carbon (3-5 mgC/L), and chlorophyll a (0.5-2.0 μg/L) in all seasons were the results of active production-destruction processes, obviously with prevalence of organic matter destruction, since the water in the bight was undersaturated with oxygen and supersaturated with carbon dioxide — the bight accumulates and mineralizes organic matter from terrestrial and riverine discharge. Underwater photographs did not detect Zostera meadows at the bottom, which were observed in the northwestern Uglovoy bight in the past. Comparison of historical data on episodic studies in the bight with results of the surveys indicates degradation of its ecosystem, with such signs as disappearance of seagrass, hypoxia in winter, and CO2 flux into the atmosphere. Reduce in water exchange between the bight and the Amur Bay caused by construction of the underwater pipeline in 1982 and the bridge in 2012 is suggested as a reason of the degradation.