Ocean Engineering Commons^™

Artificial Intelligence In Prediction Of The Remaining Useful Life Of Wind Turbine Shaft Bearings, Jinsiang Shaw, B.J. Wu

Journal of Marine Science and Technology–Taiwan

Long-term periodic rotation and unstable load changes in wind turbines can cause unexpected damage to high-speed shaft bearings (HSSBs). In this study, after preprocessing of the HSSB vibration signal, four different models for predicting bearing degradation in terms of remaining useful life (RUL) in days were investigated: support vector regression (SVR), convolutional neural networks (CNN), long short-term memory (LSTM), and CNN-LSTM. The experimental results revealed that the CNN achieved the best mean absolute error (MAE), at 0.44 days, based on frequency response plot using the fast Fourier transform (FFT), while that of the CNN-LSTM model predicted using the amplitude profile …

Impact Of Multiple Water Temperature Structures On The Behavioral Pattern Of Chum Salmon (Oncorhynchus Keta) On The Coast Of The Shiretoko Peninsula, Xinyi Li, Hiroshi Yamaguchi, Hokuto Shirakawa, Kenji Minami, Nobuhiko Sato, Yanhui Zhu, Yasuyuki Miyakoshi, Kazushi Miyashita

Journal of Marine Science and Technology–Taiwan

During the migration of chum salmon (Oncorhynchus keta) towards the Shiretoko Peninsula in Hokkaido, Japan, the convergence of coastal currents results in the formation of intricate water temperature structures. However, the impact of this phenomenon on the behavioral tendencies of chum salmon remains largely unexplored. In 2012 and 2013, we conducted a study to document the vertical water temperature profiles and uninterrupted swimming patterns of homing chum salmon in the coastal waters surrounding the Shiretoko Peninsula. The results indicated that chum salmon exhibited a preference for avoiding thermoclines characterized by rapidly decreasing water temperatures. They were predominantly observed swimming either …

Research On The Collision Risk Of Ships Off Keelung Based On Ais Data, Shih-Tzung Chen, Ming-Feng Yang, Sheng-Long Kao, Mengru Tu, Jun-Yuan Kuo, Yen-Ting Chao, Huang-Kai Hsu

Journal of Marine Science and Technology–Taiwan

In previous literature, several computational methods have been proposed to analyze collision risks for vessels navigating at sea, most of which rely on the calculation of DCPA and TCPA between two vessels. However, this study adopts an enhanced version of the Vessel Conflict Ranking Operator (VCRO) to assess vessel collision risks. This approach not only considers the relative distance and relative velocity between two vessels but also takes their relative aspect into account. This methodology was applied to real-world vessels’ dynamic data collected through AIS. From a near-collision perspective, it identifies high-risk areas near Keelung water where commercial vessels and …

Cooling Performance Analysis For Mobile Vehicles By Thermal Resistance Network, Chia-An Yang, Jung-Chang Wang, Pi-Hsia Yen

Journal of Marine Science and Technology–Taiwan

This paper used CFD software to simulate the cooling situation of the engine space of a mobile vehicle. We used thermal resistance network diagram to calculate the heat flux at each position of the power system, and discussed the CFD simulation results. The error between the simulation results and the experiment was 10.07%. The thermal resistance network diagram proposed in this paper can reduce the time for numerical simulation by evaluate the heat flux at each position of the power system.

Microbial Community And Genome Structure In Coastal Seawater From A Commercial Port And Nearby Offshore Island In Northern Taiwan, Chi-Yu Shih, Ching-Hsiang Chin, Shiow-Yi Chen, Chun-Ru Hsu, Lee-Kuo Kan, Wen-Shyong Tzou

Journal of Marine Science and Technology–Taiwan

The pollution stemming from the use of petroleum by boats, the presence of deceased marine life, hazardous chemicals, and wastewater is a major issue in human-made commercial ports. This pollution poses a considerable challenge to the diverse organisms inhabiting the seawater. To comprehend the impact of this pollution on the microbiome, we conducted a study in which we collected surface water samples from a commercial port called Keelung Port, as well as a nearby offshore island known as Keelung Islet. These locations are situated in northern Taiwan, along the Northwestern Pacific Ocean. Through the use of whole-metagenome shotgun sequencing, we …

Elevation-Distributed Multistage Reverse Osmosis Desalination With Seawater Pumped Storage, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

A seawater reverse osmosis (RO) plant layout based on multistage RO with stages located at different elevations above sea level is described. The plant uses the weight of a seawater column from pumped storage as head pressure for RO (gravity-driven multistage RO) or to supplement high-pressure pumps used in RO (gravity-assisted multistage RO). The use of gravitational force reduces the specific energy for RO compared to using high-pressure pumps. By locating the RO stages at different elevations based on demand sites, the total specific energy consumption for RO and permeate transport to different elevations above sea level is reduced from …

Interrogating The State Of Application Of Technology Within The Malawi Maritime Force As Maritime Expression : A Task-Technology Fit Approach, Gift William Kamwendo

World Maritime University Dissertations

No abstract provided.

Damage Stability Study Of A 500 Dw Ro-Ro Ferry Vessel, Zulfaidah Ariany, Budhi Santoso, Sarwoko Sarwoko, Nauval Abdurrahman Prasetyo

Makara Journal of Technology

The development of the crossing transportation industry is currently increasing in the island areas. The use of Ro-Ro type ferry boats is extremely efficient in moving people, goods, and vehicles. The current research focuses on the damage stability of the 500 DWT Ro-Ro ferry, which aims to meet the needs of the Ro-Ro ferry in the archipelago area. The previously existing initial design of a barge hull with a main size Lpp = 40.15 m, B = 12 m, H = 3.2 m, and T = 2.15 m was used to analyze the damage stability condition further. First, the drawings …

Wind-Powered Continuous Reverse Osmosis Water Desalination, Aliah Adriana Binti Khairul Hisham

Discovery Undergraduate Interdisciplinary Research Internship

Water scarcity is a grave issue that is faced by lots of people worldwide. This phenomenon is further exacerbated by climate change, overpopulation, and water-intense industrial activities. To combat this issue, reverse osmosis (RO) water desalination system is broadly introduced in order to produce freshwater while maintaining the desired thermodynamic efficiency and economic feasibility. RO water desalination is a process of separating freshwater from salt water using a semi-permeable membrane. In status quo, there are various forms of energy present in RO system (e.g: hydraulic, mechanical, electrical energy, etc.) to power the hydraulic components. The conversion from one form of …

Structural Risk-Based Underwater Inspection (Rbui) As A Cost Reduction Of Field’S End Of Production Life, Ivan Fitrian Putra, Johny Wahyuadi Soedarsono, Mirza Mahendra, Yuki Haidir, Faisal Dwiyana Purnawarman, Iwan Sukirna, Widi Hernowo

Journal of Materials Exploration and Findings

Mubadala Petroleum operates offshore platforms in a southern Makassar Straits that needs to be periodically inspected. The cost for the inspection is massive due to the high cost of mobilization and demobilization of vessels including crew and equipment. In response of a new approach to reduce cost, a Risk-Based Underwater Inspection (RBUI) methodology is developed. This RBUI purpose is to reduce the inspection interval of the offshore platform, from every 2 years to a longer period^[1]. There are existing RBUI methodologies, which are already developed and implemented in other companies^[5]. Purpose of this paper is to …

Risk Management Of Carbon Steel Piping In Sweet Environment Multiphase Fluid Production, Triadhi Panthun Tiggor, Rini Riastuti

Journal of Materials Exploration and Findings

As well reserved depleted and limited, it is necessary to lower the capital expenditure so that lifting SZ reservoir be more profitable. This article first contextualizes the effort done to increase the hydrocarbon lifting in a mature field. Despite the importance to sustain the production, and massive studies done to quantify the associate risk, no structured methodology proposed to manage the risk in respect to optimize the production expenditure by selection of carbon steel as alternative for corrosion resistance material piping. Hence, this article proposed a framework to support the decision-making process to operate in safely manner. Real case study …

The Comparison Of Pipe Thickness Selection Method Using Full Flange Rating And Non-Full Flange Rating Of Cryogenic Services In An Lng Plant Construction, Ari Agustar, Isdaryanto Iskandar, Wahyuaji Narottama Putra

Journal of Materials Exploration and Findings

Significant growth of gas demand as a source of power generation for domestic use and industries, mainly in the developed countries, has forced the effort to secure the gas supplies located thousands of miles away across the sea as an economical way of gas transportation instead of transporting by pipeline. LNG technology was created as the solution. Natural gas is refrigerated below its boiling point (-160^oC to -162^oC), known as cryogenic temperature or cryogenic service. Material of Construction (MOC) selection report showed that 304/304L and 316/316L Stainless Steel pipe could withstand and be suitable for this …

Performance Analysis: Using The Northern Sea Route As An Alternative To Traditional Routes, Liangkun Xu, Qing Yu

Journal of Marine Science and Technology–Taiwan

The grounding accident of M/V EVER GIVEN in the Suez Canal causes a catastrophic loss on shipping companies. Alternatively, previous studies have presented encouraging findings of the remarkable benefits of time and cost saving in the Northern sea route (NSR) due to extend the ice-free time and shorten the distance. Ships using the NSR could shorten as much as 40% of the sailing distance from China (Shanghai) to Europe (Rotterdam) compared with the traditional route via the Suez Canal. This paper investigates the economic potential of using the NSR as a cost-effective route in comparison with Suez Canal Route (SCR) …

Numerical And Approximate Analytic Solutions Of Second- Order Nonlinear Boundary Value Problems, Chein-Shan Liu, Jian-Hung Shen, Yung-Wei Chen

Journal of Marine Science and Technology–Taiwan

The shooting method consists of guessing unknown initial values, transforming a second-order nonlinear boundary value problem (BVP) to an initial value problem and integrating it to obtain the values at the right end to match the specified boundary condition, which acts as a target equation. In the shooting method, the key issue is accurately solving the target equation to obtain highly precise initial values. Due to the implicit and nonlinear property, we develop a generalized derivative-free Newton method (GDFNM) to solve the target equation, which offers very accurate initial values. Numerical examples are examined to show that the shooting method …

Optimization Of Circular Silencers Internally Hybridized With Multiple Reverse Chambers Using The Ga Method, Min-Chie Chiu, Ying-Chun Chang, Tian-Syung Lan, Ho-Sheng Chen

Journal of Marine Science and Technology–Taiwan

A noise abatement method using an eigen function in conjunction with an optimizer (Genetic Algorithm) under a space-constrain situation is proposed in this study concerning a high order wave propagation effect. An eigen function is used to describe an acoustical field and shorten the acoustical model in a four-pole transfer matrix form. The system’s four-pole matrix estimates the Transmission Loss (TL) for the silencers by multiplying individual four-pole matrices.

Additionally, a case study of an air compressor’s broadband noise elimination is introduced. Three types of circular reverse silencers (silencers A-C) internally hybridized with multiple straight chambers are adopted to efficiently …

Numerical Investigation Of The Uncertainty Of Typhoon Wave Parameters Retrieval Using Hf Radar, Toan Duy Dao, Hwa Chien

Journal of Marine Science and Technology–Taiwan

The aim of this study was to identify the sources of uncertainties of typhoon wave field monitoring using HF radar and to quantitatively assess the bias of the wave parameters, such as significant wave height and mean period, retrieved under various conditions. The strategy was to apply a purely numerical simulation of the Doppler-range spectra and then compare the estimation results to the target. For the quantitative investigation, a numerical test-bed was established. The test-bed was used to simulate the Doppler spectra based on Barrick’s (1972) theory by using the input of the directional wave spectra. The typhoon wave spectra …

A Fused Data Based Real-Time Collision Warning System For Ferries In The Yangtze River, Xiaojia Liu, Ke Zhang, Han Xue, Yingtang Li

Journal of Marine Science and Technology–Taiwan

The risks for ferries in the Yangtze River are relatively high, as they frequently cross the main traffic flows, leading to more intersections with other upwards and downwards ships. Although some studies have developed many models to assess collision risks in the Yangtze River, collision warning studies on ferries are scant. Meanwhile, most of the current collision studies evaluate risk based on AIS data, which are incapable of providing real-time ship information as they are discrete-time series data. In this work, fused data combining radar and AIS data are applied in a real-time ship collision warning model to assess the …

Experimental Study Of The Effect Of A Solid Wing Conveyor On Marine Debris Collection, Erik Sugianto, Jeng-Horng Chen

Journal of Marine Science and Technology–Taiwan

Marine debris is a global problem that has not been resolved. This has encouraged the emergence of marine debris cleaning technologies, one of which is a conveyor ship. However, how effective conveyors are in collecting waste has not been studied. In this paper, experimental research on conveyors as marine debris collectors is investigated. The capability of catamarans with or without solid wing conveyors to collect marine debris is explored. Three kinds of marine debris collection models are used: no-wing conveyor, a 12.5-cm-long wing conveyor, and an 18.75-cm-long wing conveyor. Artificial marine debris (AMD) is spread on the water surface in …

Solving Nonlinear Boundary Value Problems With Nonlinear Integral Boundary Conditions By Local And Nonlocal Boundary Shape Functions Methods, Chein-Shan Liu, Yung-Wei Chen, Jian-Hung Shen

Journal of Marine Science and Technology–Taiwan

The paper considers the second-order nonlinear boundary value problem (NBVP), which is equipped with nonlinear integral boundary conditions (BCs). Two novel iterative algorithms are developed to overcome the difficulty of NBVP with double nonlinearities involved. In the first iterative algorithm, two nonlocal shape functions incorporating the linear integral terms are derived, and a nonlocal boundary shape function (NBSF) is formulated to assist the solution. Let the solution be the NBSF so that the NBVP can be exactly transformed into an initial value problem. The new variable is a free function in the NBSF, and its initial values are given. For …

The Effect Of Zonation, Biofouling, And Corrosion Products On Cathodic Protection Design For Offshore Monopiles, Caglar Erdogan

Theses and Dissertations

Cathodic protection (CP) is required to prevent corrosion of the submerged steel for offshore wind monopile foundations in the marine environment. The design of these systems depends on the environmental conditions, including temperature, salinity, pH, dissolved oxygen, depth, micro- and macro-organisms, and water flow rates. The standards utilized to design cathodic protection systems consider only some of these conditions. This research identified the gaps in knowledge for the design of corrosion prevention systems for offshore wind monopile foundations and investigated the changes in cathodic current densities due to macro-galvanic cells, fouling communities and corrosion products established on uncoated vertical steel …