88 results
Search Results
Now showing 1 - 10 of 88
Item Open Access รายงานการสำรวจอุทยานทางทะเลแห่งชาติตะรุเตา ครั้งที่ 2(2520) นาท ตัณฑวิรุฬห์; ธนากร อ้วนอ่อน; มหาวิทยาลัยมหิดล. โครงการการศึกษาและวิจัยสิ่งแวดล้อม. คณะนักศึกษารุ่นปีการศึกษา 2518-19Publication Open Access Interactive Governance for the Sustainability of Marine and Coastal Resources in Thailand(2022) Suvaluck Satumantpan; Ratana ChuenpagdeeCoastal zones are biodiverse, with complex and dynamic interconnectivity between terrestrial and marine areas, and with multiple interactions between ecological and social systems. Despite on-going efforts to conserve and protect these ecosystemsPublication Open Access Assessing governability of environmental protected areas in Phetchaburi and Prachuap Kirikhan, Thailand(2015) Suvaluck Satumanatpan; Ratana Chuenpagdee; Mahidol University. Faculty of Environment and Resource Studiesinteractions. Based on these findings, we suggest that the EPA should be situated in a broader context of land and marine spatial planning and that it needs to be attuned to existing policies in a way that collaboration between agencies and policyItem Restricted Technical Guidelines on Recommendation of Guidelines to Enhance the Safety of Decommissioning Process within the Southeast Asia Regions(2024) Noor Amila Wan Abdullah Zawawi; Sarah Suherman; Nurul Anis Kamarudin; Farah Ellyza Hashim; Jin Wang; Arun Kr. Dev; Omar Yaakob; Wonsiri Punurai; Le Thi Huyen; Sari Amelia; Muhammed Amirul Asyraf Hasnanas reefing, means keeping the entire structure or certain parts of it in its current location on the seabed. This approach can serve as a habitat for marine life, and this option is typically more cost-effective than complete removal. However, a thoroughPublication Open Access Tourism threats to Coral Reef Resilience at Koh Sak, Pattaya Bay(2015-01) Phillips, Wayne N.; Mahidol University. Mahidol University International CollegeCoral reefs provide many ecosystem goods and services and rising atmospheric greenhouse gas concentrations are resulting in higher than normal sea surface temperatures (SSTs), increasing the frequency and extent of mass coral bleaching and mortality. The loss of corals after bleaching events is often followed by changes in the reef community and the proliferation of macroalgae, especially in reefs experiencing tourism and fishing. This change, however, is less likely in reefs experiencing fewer negative impacts. Using a mixed methods approach to data collection we used boat-traffic surveys, coral reef substrate surveys and self-complete questionnaires and interviews of scuba divers, island visitors and their tour guides to assess potential tourism impacts to the coral reef at Koh Sak, Pattaya. The number of tourists, the intensity of boat traffic and poor management of activities at the island impair the structural and ecological integrity of the reef thereby affecting its ecological and spatial resilience and capacity to survive global climate change. To improve reef resilience, there needs to be a shift from exploitative business practices to a conservation-based industry that creates the infrastructure to ensure visitors participate in activities that help conserve the reef rather than weaken it.Item Open Access Adaptive meta-heuristic to predict dent depth damage in the fixed offshore structures(2018) W. Punurai; M.S. Azad; N. Pholdee; C. Sinsabvarodom; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering; Khon Kaen University. Faculty of Engineering. Department of Mechanical Engineering; Norwegian University of Science and Technology. Department of Marine TechnologyThe jacket structures are often employed in the range of shallow-moderate water depth. The bracing systems and jacket legs typically use the circular section in order to compromise the hydrodynamic resistance and high torsional rigidity However, under lateral impact, these tabular bracing members are susceptible to local denting due to ship collisions or through impact of falling objects and that can weaken overall performance of the entire platform. It is a great significance for forecasting dent depth of these members accurately. This paper investigates the use of adaptive meta-heuristics algorithm to provide an automatic detection of denting damage in an offshore structure. A model is developed combining with the percentage of the dent depth of damaged member diameter and is used to assess the performance of the method. It is demonstrated that the small changes in stiffness of individual damaged bracing members are detectable from measurements of global structural motion.Item Open Access Response of Monopile Offshore Wind Turbine Structure Subjected to Seismic Loads and Degradation(2018) Yeter, Baran; Garbatov, Yordan; Guedes Soares, Carlos; Wonsiri Punurai; M.S. Azad; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering; Universidade de Lisboa. Instituto Superior Técnico. Centre for Marine Technology and Ocean Engineering (CENTEC)The objective of this work is to analyse a monopile offshore wind turbine structure subjected to the coupled loads originating from wind, soil interactions and possible seismic activities. The monopile support structure is designed to be installed at 25 m water depth to support a 5MW wind turbine. The structural assessment is performed based on the finite element method accounting for the nonlinearities associated with the geometry and material. The nonlinear structural response of the monopile structure during the seismic activity is assessed accounting for the time-variant degradation of the load-carrying capacity due to corrosion. The nonlinear response of the degrading structures at different years of the service life is presented.Publication Open Access Effects of Redundancy in Bracing Systems on the Fragility Curve Development of Steel Jacket Offshore Platform(2019) M.S. Azad; Wonsiri Punurai; Chana Sinsabvarodom; Pornpong Asavadorndeja; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering; Norwegian University of Science and Technology. Department of Marine Technology; Synterra Co., LtdSteel jacket offshore platforms are typically employed for use in shallow to moderate water depths. During platform operations, there have been some historical accidents completely damaging the diagonal members of the bracing systems due to explosions, fire accidents and dropped objects. Different locations of damaged bracings demonstrate different levels of risk for safety and integrity of the structures. This research illustrates the effects of redundancy in the bracing systems for steel jacket offshore platforms. Assessments have been carried out using the nonlinear pushover analysis method and formations of nonlinear hinges of different members were noted. Redundancy in different positions has been considered to investigate the consequences. Reserve strength ratio (RSR) and damage strength ratio (DSR) of the global structure were also evaluated to understand the importance of different local members. From the collapse data of local failures, fragility curves for the global structures were estimated. The results demonstrated that the position of damage can be a great concern which affects the overall performance of the structures.Publication Open Access Modelling Assessment of Sandy Beaches Erosion in Thailand(2019) Hiripong Thepsiriamnuay; Nathsuda Pumijumnong; Mahidol University. Faculty of Environment and Resource StudiesThis paper focuses on the spatial and temporal aspects of rising sea levels and sandy beach erosion in Thailand. The major scientific challenge tackled in this paper was to distinguish the relevance and contribution of sea level rise (including storms) to beach erosion. The Simulator of Climate Change Risks and Adaptation Initiatives (SimCLIM) and its’ impact model (CoastCLIM) with two representative concentration pathway (RCP) scenarios (RCP2.6 and RCP8.5) was utilized to forecast changes in sea level and shoreline between the years 1940-2100. Input parameters underlying the modified Brunn Rule were applied (e.g., coastal and storm characteristics). Moreover, sand loss and forced people migration were estimated using fundamental equations. The sea level is predicted to rise by 147.90 cm and the coastline will be eroded around 517.09 m by 2100, compared to levels in 1995. This level of erosion could lead to a decrease of the coastal sandy area by about 2.69 km2and a population of 873 people, over the same period. In scientific terms, this paper quantifies the contribution and relevance of sea-level rise (SLR) to sandy beach erosion compared to other factors, including ad-hoc short-term impacts from stochastic storminess. The results also showed that 8.02 and 23.26 percent of erosion was attributed to storms and sea-level rise, respectively. Nevertheless, limited multi-century data of residual movement in Thailand could create uncertainties in distinguishing relative contributions. These results could be beneficial to national-scale data and the adaptation planning processes in Thailand.Publication Open Access A novel hybridized metaheuristic technique inenhancing the diagnosis of cross-sectional dentdamaged offshore platform members(2019) Wonsiri Punurai; M.S. Azad; Nantiwat Pholdee; Sujin Bureerat; Chana Sinsabvarodom; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering; Khon Kaen University. Faculty of Engineering. Sustainable and Infrastructure Research and Development Center; Norwegian University of Science and Technology. Faculty of Engineering. Department of Marine TechnologyOffshore jacket platforms are widely used for oil and gas extraction as well as transportation in shallow to moderate water depth. Tubular cross-sectional elements are used to construct offshore platforms. Tubular cross-sections impart higher resistance against hydrodynamic forces and have high torsional rigidity. During operation, the members can be partially or fully damaged due to lateral impacts. The lateral impacts can be due to ship collisions or through the impact of falling objects. The impact forces can weaken some members that influence the overall performance of the platform. This demonstrates an urgent need to develop a framework that can accurately forecast dent depth as well as dent angle of the affected members. This study investigates the use of an adaptive metaheuristics algorithm to provide automatic detection of denting damage in an offshore structure. The damage information includes dent depth and the dent angle. A model is developed in combination with the percentage of the dent depth of the damaged member and is used to assess the performance of the method. It demonstrates that small changes in stiffness of individual damaged bracing members are detectable from measurements of global structural motion