Yukiyasu Noguchi, M. Humblet, Y. Furushima, Shohei Ito, T. Maki
Abstract Surveys and monitoring are essential to study the biology and ecology of coral reefs in order to understand the reasons behind reef demise and recovery. However, mesophotic coral ecosystems (MCEs) remain largely unknown compared to their shallow counterparts because it is difficult to observe the seafloor below 30 m depths. Here, we propose a seafloor observation method using a low-cost autonomous underwater vehicle (AUV). This method was developed to allow many people to easily perform underwater observations of MCEs, and is also applicable to general seafloor surveys, such as underwater artificial structures, hydrothermal vent fields, etc. The method possesses three important attributes to achieve effective surveys. First, it can be applied in highly rugged terrains and enables the AUV to track omnidirectional surfaces at high speed (Max. ~1 m/s). Second, it can produce a reliable three-dimensional (3D) image of the seafloor based on a depth sensor. Third, it can be used to estimate the flow velocity field. The proposed method was tested by using the AUV HATTORI-2, which is a lightweight, one-man portable AUV equipped with commercial off-the-shelf sensors. Our study area is the Sekisei Lagoon in the South Ryukyus, which represents the largest coral reef complex in Japan. The method enabled us not only to obtain a wide and high-definition 3D image of mesophotic coral reefs that captures detailed characteristics of marine habitats but also to acquire environmental data, such as flow velocity field and seawater temperature, spatially and temporally aligned with the 3D image.
为了了解珊瑚礁消亡和恢复的原因，调查和监测是研究珊瑚礁生物学和生态学的必要条件。然而，与浅层珊瑚生态系统相比，中孔珊瑚生态系统(MCEs)在很大程度上仍然未知，因为很难观察到30米以下的海底。在此，我们提出了一种使用低成本自主水下航行器(AUV)的海底观测方法。该方法的发展是为了方便许多人进行mce的水下观测，也适用于一般的海底调查，如水下人工结构，热液喷口场等。该方法具有三个重要属性，以实现有效的调查。首先，它可以应用于高度崎岖的地形，使AUV能够以高速(最大时速)跟踪全向表面。~ 1 m / s)。其次，它可以基于深度传感器生成可靠的海底三维(3D)图像。第三，它可以用来估计流速场。提出的方法通过AUV HATTORI-2进行了测试，这是一种轻型的单人便携式AUV，配备了商用现成的传感器。我们的研究区域是南琉球的Sekisei泻湖，它代表了日本最大的珊瑚礁群。该方法不仅可以获得捕获海洋栖息地详细特征的宽分辨率介孔珊瑚礁三维图像，还可以获得与三维图像在空间和时间上一致的流速场和海水温度等环境数据。
{"title":"Wide-Area Three-Dimensional Imaging of Mesophotic Coral Reefs Using a Low-Cost AUV","authors":"Yukiyasu Noguchi, M. Humblet, Y. Furushima, Shohei Ito, T. Maki","doi":"10.4031/mtsj.56.4.4","DOIUrl":"https://doi.org/10.4031/mtsj.56.4.4","url":null,"abstract":"Abstract Surveys and monitoring are essential to study the biology and ecology of coral reefs in order to understand the reasons behind reef demise and recovery. However, mesophotic coral ecosystems (MCEs) remain largely unknown compared to their shallow counterparts because\u0000 it is difficult to observe the seafloor below 30 m depths. Here, we propose a seafloor observation method using a low-cost autonomous underwater vehicle (AUV). This method was developed to allow many people to easily perform underwater observations of MCEs, and is also applicable to general\u0000 seafloor surveys, such as underwater artificial structures, hydrothermal vent fields, etc. The method possesses three important attributes to achieve effective surveys. First, it can be applied in highly rugged terrains and enables the AUV to track omnidirectional surfaces at high speed (Max.\u0000 ~1 m/s). Second, it can produce a reliable three-dimensional (3D) image of the seafloor based on a depth sensor. Third, it can be used to estimate the flow velocity field. The proposed method was tested by using the AUV HATTORI-2, which is a lightweight, one-man portable AUV equipped\u0000 with commercial off-the-shelf sensors. Our study area is the Sekisei Lagoon in the South Ryukyus, which represents the largest coral reef complex in Japan. The method enabled us not only to obtain a wide and high-definition 3D image of mesophotic coral reefs that captures detailed characteristics\u0000 of marine habitats but also to acquire environmental data, such as flow velocity field and seawater temperature, spatially and temporally aligned with the 3D image.","PeriodicalId":49878,"journal":{"name":"Marine Technology Society Journal","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41947156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Many ports around the world are threatened by sea ice. Access by merchant ships to these ports is ensured by ice-breaking services. For the sensitivity of calculations of the amount of cargo on vessels carrying out loading and discharging in waters covered with ice, the calculations need to be modified. This study aims to investigate the effects of sea ice in different thicknesses on the calculations of the cargo amounts, especially the effects on the tonnage per centimeter (TPC) values of the vessels. There is a limited number of studies on ice resistance of zero-speed vessels. An experimental study was performed to gauge the impact of ice on vessel draughts on a scale ship model. The scaled TPC weights were applied under two separate loading conditions on the scale model ship. Such processes were repeated for various ice thicknesses. The results indicated that an increase in TPC values was in a linear relationship with ice thickness and was found under both loading conditions. In analyses based on the scale model according to the draft marks, the ice friction created an overloaded case. In the stability booklets, it is assumed that adding the amount of increase in TPC value as a correction would resolve disputes over the amount of loaded cargo and can circumvent overloading cases.
{"title":"An Empirical Study on the Effects of Sea Ice on Ship Tonnage per Centimeter and Cargo Operations","authors":"İdris Turna, G. Kara, D. B. Danişman","doi":"10.4031/mtsj.56.4.1","DOIUrl":"https://doi.org/10.4031/mtsj.56.4.1","url":null,"abstract":"Abstract Many ports around the world are threatened by sea ice. Access by merchant ships to these ports is ensured by ice-breaking services. For the sensitivity of calculations of the amount of cargo on vessels carrying out loading and discharging in waters covered with ice,\u0000 the calculations need to be modified. This study aims to investigate the effects of sea ice in different thicknesses on the calculations of the cargo amounts, especially the effects on the tonnage per centimeter (TPC) values of the vessels. There is a limited number of studies on ice resistance\u0000 of zero-speed vessels. An experimental study was performed to gauge the impact of ice on vessel draughts on a scale ship model. The scaled TPC weights were applied under two separate loading conditions on the scale model ship. Such processes were repeated for various ice thicknesses. The results\u0000 indicated that an increase in TPC values was in a linear relationship with ice thickness and was found under both loading conditions. In analyses based on the scale model according to the draft marks, the ice friction created an overloaded case. In the stability booklets, it is assumed that\u0000 adding the amount of increase in TPC value as a correction would resolve disputes over the amount of loaded cargo and can circumvent overloading cases.","PeriodicalId":49878,"journal":{"name":"Marine Technology Society Journal","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45627395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Marine Autonomous Surface Ships (MASS) are gaining increasing attention due to the potential benefits of improving safety and efficiency. The paper presents the trends in the development of autonomous ships and reliability modeling carried out to assess the maturity of Guidance, Navigation, Control, Power and Propulsion (GNCPP) subsystems that are critical for safe and reliable operation of MASS. Based on the simulations with field-failure data as inputs, it is identified that a typical vessel GNCPP system can have a mean time to fail period of 1.2 years. The emergency shore support systems shall require a proof test interval of 22 days to comply with IEC61508 HSE Safety Integrity Level 3 of on-demand availability. The results could help in efficient maintenance planning and integrity management of the autonomous ship systems. The efforts required to realize situation-aware autonomous navigation technologies complying with stringent operational regulatory frameworks are also discussed.
{"title":"Assessment of the Technological Maturity of Marine Autonomous Surface Ships","authors":"N. Vedachalam","doi":"10.4031/mtsj.56.4.16","DOIUrl":"https://doi.org/10.4031/mtsj.56.4.16","url":null,"abstract":"Abstract Marine Autonomous Surface Ships (MASS) are gaining increasing attention due to the potential benefits of improving safety and efficiency. The paper presents the trends in the development of autonomous ships and reliability modeling carried out to assess the maturity\u0000 of Guidance, Navigation, Control, Power and Propulsion (GNCPP) subsystems that are critical for safe and reliable operation of MASS. Based on the simulations with field-failure data as inputs, it is identified that a typical vessel GNCPP system can have a mean time to fail period of 1.2 years.\u0000 The emergency shore support systems shall require a proof test interval of 22 days to comply with IEC61508 HSE Safety Integrity Level 3 of on-demand availability. The results could help in efficient maintenance planning and integrity management of the autonomous ship systems. The efforts required\u0000 to realize situation-aware autonomous navigation technologies complying with stringent operational regulatory frameworks are also discussed.","PeriodicalId":49878,"journal":{"name":"Marine Technology Society Journal","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43931232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Ge, C. Cao, Jia-wang Chen, Hao Wang, Peihao Zhang, Jiamin He, Yuan Lin
Abstract Submarine hydrate mounds are important indicators of submarine methane seepages, hydrocarbon reservoirs, and seabed instability. In order to fully understand the formation of hydrate mounds, here, we review the study of hydrate mounds, in which the morphology, the formation mechanism, as well as the research techniques are introduced. The formation mechanism of hydrate mounds can be classified into: (1) The sediment volume expands due to the formation and accumulation of shallow hydrates; (2) unconsolidated shallow sediment layers respond mechanically to increasing pore pressure caused by shallow gas accumulation; (3) materials extrude from submarine layers driven by the over-pressure caused by shallow gas accumulation; and (4) the interaction of multiple factors. Most hydrate mounds occur in submarine gas hydrate occurrence areas. Active hydrate mounds are circular or ellipse well-rounded shaped, with gas seepages and abundant organisms, whereas inactive hydrate mounds are rough or uneven irregular shaped, with low flux of fluid in the migration channel. Due to the limitation of long-term in-situ observation technology, the existing observation method makes it possible to provide basic morphology features, stratigraphic structures, and fluid migration channels of the hydrate mound. Future research should be focused on the long-term in-situ monitoring technology, the formation mechanism of the hydrate mounds, and the role of gas hydrates in the seafloor evolution. In addition, the features of hydrate mounds (e.g., gas chimneys and fluid migration conduits) and the relationship between hydrate mounds and pockmarks could be further studied to clarify the influence of methane release from hydrate mounds on biogeochemical processes and the atmospheric carbon contents.
{"title":"Monitoring and Research on Submarine Hydrate Mound: Review and Future Perspective","authors":"Y. Ge, C. Cao, Jia-wang Chen, Hao Wang, Peihao Zhang, Jiamin He, Yuan Lin","doi":"10.4031/mtsj.56.4.14","DOIUrl":"https://doi.org/10.4031/mtsj.56.4.14","url":null,"abstract":"Abstract Submarine hydrate mounds are important indicators of submarine methane seepages, hydrocarbon reservoirs, and seabed instability. In order to fully understand the formation of hydrate mounds, here, we review the study of hydrate mounds, in which the morphology, the\u0000 formation mechanism, as well as the research techniques are introduced. The formation mechanism of hydrate mounds can be classified into: (1) The sediment volume expands due to the formation and accumulation of shallow hydrates; (2) unconsolidated shallow sediment layers respond mechanically\u0000 to increasing pore pressure caused by shallow gas accumulation; (3) materials extrude from submarine layers driven by the over-pressure caused by shallow gas accumulation; and (4) the interaction of multiple factors. Most hydrate mounds occur in submarine gas hydrate occurrence areas. Active\u0000 hydrate mounds are circular or ellipse well-rounded shaped, with gas seepages and abundant organisms, whereas inactive hydrate mounds are rough or uneven irregular shaped, with low flux of fluid in the migration channel. Due to the limitation of long-term in-situ observation technology, the\u0000 existing observation method makes it possible to provide basic morphology features, stratigraphic structures, and fluid migration channels of the hydrate mound. Future research should be focused on the long-term in-situ monitoring technology, the formation mechanism of the hydrate mounds,\u0000 and the role of gas hydrates in the seafloor evolution. In addition, the features of hydrate mounds (e.g., gas chimneys and fluid migration conduits) and the relationship between hydrate mounds and pockmarks could be further studied to clarify the influence of methane release from hydrate\u0000 mounds on biogeochemical processes and the atmospheric carbon contents.","PeriodicalId":49878,"journal":{"name":"Marine Technology Society Journal","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70232322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Globally, there has been a substantial growth in interest in autonomous surface ships. This new domain presents numerous concerns for enhanced reader comprehension. The most crucial topic to consider is the safety of autonomous ships and the risks they present. To enable the use of autonomous ships, they must be as safe for the environment and for people as manned surface ships. However, as it has not yet been widely implemented, acquiring real-time data restricts the scope of the study. The objective of this paper is to conduct a comprehensive quantitative risk analysis for maritime autonomous surface ships (MASS). Therefore, it focuses on the operations to be performed by MASS and the factors that may pose a risk. In this context, Hazard and Operability Analysis (HAZOP) and Cognitive Reliability and Error Analysis Method (CREAM) approaches will be used in risk analysis assessment. While the HAZOP method will be used to determine the deviations, causes, possible consequences, and measurements that autonomous surface ships will be exposed to, the extended CREAM will be used to determine the likelihood of occurrence and risk levels of the MASS operation. The outcomes of the paper are anticipated to enhance the safety operational safety level of autonomous ships as well as mitigate risks.
{"title":"A Quantitative HAZOP Risk Analysis Under Extended CREAM Approach for Maritime Autonomous Surface Ship (MASS) Operation","authors":"Yasin Burak Kurt, E. Akyuz, O. Arslan","doi":"10.4031/mtsj.56.4.11","DOIUrl":"https://doi.org/10.4031/mtsj.56.4.11","url":null,"abstract":"Abstract Globally, there has been a substantial growth in interest in autonomous surface ships. This new domain presents numerous concerns for enhanced reader comprehension. The most crucial topic to consider is the safety of autonomous ships and the risks they present. To\u0000 enable the use of autonomous ships, they must be as safe for the environment and for people as manned surface ships. However, as it has not yet been widely implemented, acquiring real-time data restricts the scope of the study. The objective of this paper is to conduct a comprehensive quantitative\u0000 risk analysis for maritime autonomous surface ships (MASS). Therefore, it focuses on the operations to be performed by MASS and the factors that may pose a risk. In this context, Hazard and Operability Analysis (HAZOP) and Cognitive Reliability and Error Analysis Method (CREAM) approaches\u0000 will be used in risk analysis assessment. While the HAZOP method will be used to determine the deviations, causes, possible consequences, and measurements that autonomous surface ships will be exposed to, the extended CREAM will be used to determine the likelihood of occurrence and risk levels\u0000 of the MASS operation. The outcomes of the paper are anticipated to enhance the safety operational safety level of autonomous ships as well as mitigate risks.","PeriodicalId":49878,"journal":{"name":"Marine Technology Society Journal","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46792397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract A climate-resilient and eco-friendly maritime transport is the key to sustainable development. In response to the Paris Climate Accord, the International Maritime Organization has adopted strategies to reduce greenhouse gas emissions from ships by ~50% by 2050, compared to levels reported in 2008. The article reviews the ongoing efforts toward achieving clean, safe, and efficient marine transport. The transformation pathway requires sustained innovation, investment, and policy support in economic production and reliable supply for ammonia and hydrogen fuels, battery-based hybrid power systems for support vessels, artificial intelligence-enabled autonomous ships, energy-efficient and low-noise ship design, and improved operational planning.
{"title":"Climate-Resilient and Eco-Friendly Shipping: Mapping the Trends","authors":"Manickavasagam Palaniappan, N. Vedachalam","doi":"10.4031/mtsj.56.4.12","DOIUrl":"https://doi.org/10.4031/mtsj.56.4.12","url":null,"abstract":"Abstract A climate-resilient and eco-friendly maritime transport is the key to sustainable development. In response to the Paris Climate Accord, the International Maritime Organization has adopted strategies to reduce greenhouse gas emissions from ships by ~50% by 2050, compared\u0000 to levels reported in 2008. The article reviews the ongoing efforts toward achieving clean, safe, and efficient marine transport. The transformation pathway requires sustained innovation, investment, and policy support in economic production and reliable supply for ammonia and hydrogen fuels,\u0000 battery-based hybrid power systems for support vessels, artificial intelligence-enabled autonomous ships, energy-efficient and low-noise ship design, and improved operational planning.","PeriodicalId":49878,"journal":{"name":"Marine Technology Society Journal","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41698859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Humankind is at a crossroads of sorts with respect to the abundantly available deep-sea mineral resources that can serve as a potential alternative to the requirement of certain materials critical for industrial as well as domestic consumption. While on one hand, these minerals are essential to transition to green energy alternatives, on the other hand, there remains the question of the likely environmental, social, and cultural implications. This commentary poses questions that need to be answered in order to see whether deep-sea mining is a feasible option.
{"title":"Undertaking Deep-Sea Mining: A Quest for the Right Answers","authors":"Rahul Sharma","doi":"10.4031/mtsj.56.4.13","DOIUrl":"https://doi.org/10.4031/mtsj.56.4.13","url":null,"abstract":"Abstract Humankind is at a crossroads of sorts with respect to the abundantly available deep-sea mineral resources that can serve as a potential alternative to the requirement of certain materials critical for industrial as well as domestic consumption. While on one hand,\u0000 these minerals are essential to transition to green energy alternatives, on the other hand, there remains the question of the likely environmental, social, and cultural implications. This commentary poses questions that need to be answered in order to see whether deep-sea mining is a feasible\u0000 option.","PeriodicalId":49878,"journal":{"name":"Marine Technology Society Journal","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42493338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Due to the rising demands for applications in extreme environments and technological breakthroughs, today's marine equipment system is increasingly intricate and powerful. As a result, the issue of reliability is gaining prominence. One of the most efficient approaches in reliability analysis is Fault Tree Analysis (FTA). The FTA method and the Monte Carlo simulation were used to access the system reliability of a full-ocean-depth unmanned submersible (FODUS). The life distribution function of the system is determined, and the FODUS system's Mean Time Between Failures and the importance index of each basic component are calculated. The results will serve as a reference for future research on the reliability of deep-sea submersibles.
{"title":"Fault Tree Analysis of a Full-Ocean-Depth Unmanned Submersible","authors":"Ruilong Luo, Y. Guo, Fang Wang, Youjie Li, Shuai Li, Jinfei Zhang, Zhe Jiang","doi":"10.4031/mtsj.56.4.3","DOIUrl":"https://doi.org/10.4031/mtsj.56.4.3","url":null,"abstract":"Abstract Due to the rising demands for applications in extreme environments and technological breakthroughs, today's marine equipment system is increasingly intricate and powerful. As a result, the issue of reliability is gaining prominence. One of the most efficient approaches\u0000 in reliability analysis is Fault Tree Analysis (FTA). The FTA method and the Monte Carlo simulation were used to access the system reliability of a full-ocean-depth unmanned submersible (FODUS). The life distribution function of the system is determined, and the FODUS system's Mean Time Between\u0000 Failures and the importance index of each basic component are calculated. The results will serve as a reference for future research on the reliability of deep-sea submersibles.","PeriodicalId":49878,"journal":{"name":"Marine Technology Society Journal","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49322211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Cao, Y. Ge, Jia-wang Chen, Hao Wang, Han Ge, P. Zhou, F. Gao, Yan Sheng, Lieyu Tian, Yifan Huang
Abstract As an important green energy source for the future, deep-sea natural gas hydrate has attracted worldwide attention in recent years, and several trial exploitations have been carried out. Hydrates are prone to decomposition leading to terrain subsidence; hence, there is an urgent need to monitor terrain change during the exploration. In this study, a monitoring device based on six-axis Micro-Electro-Mechanical System array is developed to monitor the terrain subsidence during production of gas hydrate. The liability of the device has been tested both by lab experiments and a sea trial in the “Shenhu” area of the South China Sea with water-depth of 1,203 m. The device performed in-situ monitoring for 193 consecutive days; the deformation of the seafloor terrain has been successfully measured, and the seafloor topography has been obtained and reconstructed, showing that the overall average uplift of the seafloor terrain is 0.82 cm, with a maximum uplift of 5.98 cm and a maximum subsidence of 3.21 cm. The result shows that the geological conditions in the “Shenhu” area are stable, which provide a reference for the development of hydrates.
{"title":"Research on Terrain Monitoring Device of Natural Gas Hydrate Trial Production Area in the Sea","authors":"C. Cao, Y. Ge, Jia-wang Chen, Hao Wang, Han Ge, P. Zhou, F. Gao, Yan Sheng, Lieyu Tian, Yifan Huang","doi":"10.4031/mtsj.56.4.5","DOIUrl":"https://doi.org/10.4031/mtsj.56.4.5","url":null,"abstract":"Abstract As an important green energy source for the future, deep-sea natural gas hydrate has attracted worldwide attention in recent years, and several trial exploitations have been carried out. Hydrates are prone to decomposition leading to terrain subsidence; hence, there\u0000 is an urgent need to monitor terrain change during the exploration. In this study, a monitoring device based on six-axis Micro-Electro-Mechanical System array is developed to monitor the terrain subsidence during production of gas hydrate. The liability of the device has been tested both by\u0000 lab experiments and a sea trial in the “Shenhu” area of the South China Sea with water-depth of 1,203 m. The device performed in-situ monitoring for 193 consecutive days; the deformation of the seafloor terrain has been successfully measured, and the seafloor topography has been\u0000 obtained and reconstructed, showing that the overall average uplift of the seafloor terrain is 0.82 cm, with a maximum uplift of 5.98 cm and a maximum subsidence of 3.21 cm. The result shows that the geological conditions in the “Shenhu” area are stable, which provide a reference\u0000 for the development of hydrates.","PeriodicalId":49878,"journal":{"name":"Marine Technology Society Journal","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46700872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The Mir-1 and Mir-2 submersibles (6,000 m) were built in 1987. In over 30 years of use, the submersibles were deployed in many deep ocean operations for scientific research; for filming with Hollywood, IMAX, BBC, etc.; as well as for dives to solve special tasks in great depths. In this article, the author discusses two unique operations with Mirs: live broadcast from the Titanic (3,800 m) and the attempt to raise the safety capsule of the nuclear submarine Komsomolets in the Norwegian sea (1,700 m).
{"title":"Two Unique Deep Ocean Operations With the Mir Submersibles","authors":"A. Sagalevich","doi":"10.4031/mtsj.56.4.2","DOIUrl":"https://doi.org/10.4031/mtsj.56.4.2","url":null,"abstract":"Abstract The Mir-1 and Mir-2 submersibles (6,000 m) were built in 1987. In over 30 years of use, the submersibles were deployed in many deep ocean operations for scientific research; for filming with Hollywood, IMAX, BBC, etc.; as well as for dives to solve\u0000 special tasks in great depths. In this article, the author discusses two unique operations with Mirs: live broadcast from the Titanic (3,800 m) and the attempt to raise the safety capsule of the nuclear submarine Komsomolets in the Norwegian sea (1,700 m).","PeriodicalId":49878,"journal":{"name":"Marine Technology Society Journal","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41819670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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