Research on Anti-Corrosion and Coating Technology of Outer Pipes of Submarine Pipelines Shallow Sea by Physical Testing

In this paper, by discussing the characteristics of the beach and shallow sea marine environment, combining with engineering design and application, studying the anti-corrosion coating and coating technology of the outer pipe of the pipeline, and analyzing the design of the concrete counterweight layer of the submarine pipeline. According to the submarine pipeline of the environment, structural characteristics, construction methods, etc, the reasons for the damage of the external protective coating under certain conditions are explained, so as to select the external protective coating more reasonably, and provide data for the anti-corrosion and coating selection of the marine pipeline.

Mussel biology: from the byssus to ecology and physiology, including microplastic ingestion and deep-sea adaptations

Mussels are a group of bivalves that includes the dominant species of shallow-sea, freshwater, and deep-sea chemosynthetic ecosystems. Mussels cling to various solid underwater surfaces using a proteinaceous thread, called the byssus, which is central to their ecology, physiology, and evolution. Mussels cluster using their byssi to form “mussel beds,” thereby increasing their biomass per unit of habitat area, and also creating habitats for other organisms. Clustered mussels actively filter feed to obtain nutrients, but also ingest pollutants and suspended particles; thus, mussels are good subjects for pollution analyses, especially for microplastic pollution. The byssus also facilitates invasiveness, allowing mussels to hitchhike on ships, and to utilize other man-made structures, including quay walls and power plant inlets, which are less attractive to native species. Physiologically, mussels have adapted to environmental stressors associated with a sessile lifestyle. Osmotic adaptation is especially important for life in intertidal zones, and taurine is a major component of that adaptation. Taurine accumulation systems have also been modified to adapt to sulfide-rich environments near deep-sea hydrothermal vents. The byssus may have also enabled access to vent environments, allowing mussels to attach to “evolutionary stepping stones” and also to vent chimneys.

Study of the relationship between dispersion distortions of impulsive signals and acoustic properties of the shallow sea bottom

Для установления связи между дисперсионными искажениями сигналов и акустическими характеристиками дна мелкого моря применяется метод свертки сигнала с импульсной характеристикой волновода. Методом нормальных волн вычисляется акустическое поле в широкой полосе частот. Затем осуществляется обратное преобразование Фурье акустического поля и восстанавливается импульсная характеристика волновода. Реплика сигнала далее вычисляется как свертка импульсной характеристики и сигнала. Преимущества такого подхода следующие. Свертка циклична – нет ограничений на длительность сигнала. Может быть использована не только вычисленная, но и экспериментально определенная импульсная характеристика. По усмотрению исследователя поля отдельных мод можно исключать, добавлять шум в частотной либо временной области, имитировать движение источника, воздействие ветрового волнения. Ограничение – условия однородности волновода вдоль трассы. Рассматривается ряд примеров, в которых изучается возможность определения акустических свойств дна, изучаются дисперсионные искажения сигналов, возникающие в волноводе со слоем скачка скорости звука на профиле скорости звука. Изучается изменение дисперсионных искажений в зависимости от частоты сигнала, глубины приемника, расстояния между излучателем и приемником. To establish a connection between the dispersion distortions of signals and the acoustic properties of the shallow sea bottom, the method of convolution of the signal with the impulse response of the waveguide is used. The method of normal modes calculates the acoustic field in a wide frequency band. Then the inverse Fourier transform of the acoustic field is performed and the impulse response of the waveguide is restored. The signal replica is then calculated as a convolution of the impulse response and the signal. The advantages of this approach are as follows. Convolution is cyclical – there are no restrictions on the duration of the signal. Not only calculated, but also experimentally determined impulse response can be used. At the discretion of the researcher, the fields of individual modes can be excluded, add noise in the frequency or time domain, simulate the movement of the source, the impact of wind waves. Restriction - conditions for uniformity of the waveguide along the distance. A number of examples are considered, in which the possibility of determining the acoustic properties of the bottom is studied, as well as dispersion distortions of signals that occur in a waveguide with a sound velocity jump layer on the sound velocity profile. The variation of dispersion distortions is studied depending on the signal frequency, receiver depth, and distance between the emitter and receiver.

DISTRIBUTION OF SUBSURFACE QUATERNARY SEDIMENT IN SOUTH BINTAN ISLAND WATERS AS A POTENTIAL HEAVY MINERAL PLACER OR RARE EARTH ELEMENT DEPOSIT BASED ON SEISMIC INTERPRETATION

Bintan Island is one of the areas traversed by the Southeast Asian granitoid belt which is known to have the potential for heavy mineral placer deposits. Due to the dwindling presence of heavy mineral placer deposits in land areas, it is necessary to look for the potential presence of heavy mineral placer deposits in water areas. Searching for placer heavy mineral deposits accomodation in these waters requires subsurface mapping.The method used in this subsurface mapping is a single channel seismic method with a total of 179 lines in the direction of northeast – southwest and west – east. The results of this seismic recording are then interpreted the boundaries of the seismic facies unit and distributed using the kriging method. Furthermore, the thickness calculates by using the assumption velocity 1600 m/s.Based on the facies unit boundaries that have been interpreted, the quaternary sediments that formed in the study area are divided into 2 types of units, namely: Unit 2 which is estimated to be fluvial – transitional sediment, and Unit 1 which is estimated to be transitional sediment – shallow sea. There is also a difference in thickness patterns in these two units, where unit 2 shows a pattern of sediment thickening that resembles a paleochannel trending northeast – southwest, while unit 1 is relatively uniform.From the results of this study, it can be said that the area that has potential for heavy mineral placer deposits is in the west - center of the southern waters of Bintan Island. Where the potential for heavy mineral placer deposits should be in the paleochannel deposits that are part of Unit 2.