Exhaust Noise Elimination Using Silencers Fortified With Perforated Tubes, Extended Tubes, Penetrable Resin Inlet And Orifice Plate,
2023
Department of Mechanical and Materials Engineering, Tatung University, ROC
Exhaust Noise Elimination Using Silencers Fortified With Perforated Tubes, Extended Tubes, Penetrable Resin Inlet And Orifice Plate, Min-Chie Chiu, Ho-Chih Cheng
Journal of Marine Science and Technology–Taiwan
Pneumatic equipment in marine diesel engine and associated piping system often emit extremely high level of noises when releasing pressure. Concerning the crew’s hearing health, discovering an efficient noise silencing device becomes essential. A silencer fortified with extended tubes, perforated tubes, orifice plate, and penetrable resin inlet is presented in order to competently dampen the blown-up noises. A simplified objective function by means of FEM, Artificial Neural Networks (ANNs), and a Genetic Algorithm (GA) is established to enable the numerical calculation when using a finite element method. Three silencer designs, silencer A (with element A, a penetrable resin inlet), B …
Deep Learning–Based, Oceantdlx Sea Ice Detection Model For Sar Image,
2023
Shandong University of Science and Technology, Qingdao, China.
Deep Learning–Based, Oceantdlx Sea Ice Detection Model For Sar Image, Liu Lin, Li Wanwu, Li Hang, Sun Yi
Journal of Marine Science and Technology–Taiwan
This study constructs four deep-learning OceanTDLx series models and uses a WinR-AdaGrad gradient descent algorithm to train and optimize the constructed models. Through an analysis of the loss, accuracy, and time consumption of the four models (i.e., OceanTDL2, OceanTDL3, OceanTDL5 and OceanTDL8), we reveal that the models’ performance does not improve when the number of layers is increased and that OceanTDL5 provides the optimal performance. OceanTDL5 is compared with OceanTDA9 (a model that we previously constructed), and the curves for training loss_batch and training accuracy_batch indicate that OceanTDL5 is more suitable than OceanTDA9 for detecting distributed targets, particularly semi-melted sea …
Application Of Unmanned Aerial Vehicle–Based Infrared Images In Determining Characteristics Of Sea Surface Temperature Distribution,
2023
Assistant Professor, Department of Shipping Technology, College of Maritime, National Kaohsiung University of Science and Technology
Application Of Unmanned Aerial Vehicle–Based Infrared Images In Determining Characteristics Of Sea Surface Temperature Distribution, Hsing-Yu Wang, Hui-Ming Fang, Yun-Chih Chiang
Journal of Marine Science and Technology–Taiwan
This study investigated the temperature field of a body of water by using rotary-wing unmanned aerial vehicles (DJI Mavic 2 Enterprise Dual) comprising visible light and infrared cameras to determine sea temperature distribution. With a flight height of 150 m, image overlap of 80%, and image resolution of 4.75 cm/pixel, the proposed method was more effective than the conventional portable conductivity–temperature–depth device in rapidly measuring sea surface temperature and determining sea temperature distribution. The discharged heated water of the Hoping Power Plant traveled 100–330 m from the wastewater outfall and then gradually diffused in the range of 100–490 m before …
Time Series Analysis Of Pseudo-Nitzschia Species Composition, Domoic Acid, And Environmental Conditions In The Gulf Of Maine From 2013-2020,
2023
University of South Florida
Time Series Analysis Of Pseudo-Nitzschia Species Composition, Domoic Acid, And Environmental Conditions In The Gulf Of Maine From 2013-2020, Christina Chadwick
USF Tampa Graduate Theses and Dissertations
Phytoplankton are abundant in both fresh and marine waters and can form harmful algal blooms (HABs) by producing potent toxins that have devastating effects on human, wildlife, and economic health. The HAB-forming diatom genus, Pseudo-nitzschia, occurs globally and approximately half of the 59 currently identified species can produce the neurotoxin, domoic acid (DA). DA accumulates in shellfish and finfish and can cause Amnesic Shellfish Poisoning (ASP) in humans and DA Poisoning (DAP) in several species of wildlife, resulting in severe neurological dysfunction and mortality. Along with these health threats, DA toxicity is a major economic threat for shellfish and fish …
Heat Flux Dynamics And Seasonal Variability In Morro Bay, California,
2023
California Polytechnic State University, San Luis Obispo
Heat Flux Dynamics And Seasonal Variability In Morro Bay, California, Mikaela Romanini
Master's Theses
There is a growing need to better understand the dynamics of small and medium Mediterranean low-inflow estuaries (LIEs), which is addressed here by characterizing a heat budget and associated heat transfer processes. A one-dimensional deterministic model was developed from the advection-diffusion equation and applied to Morro Bay, CA using 15-minute water property (temperature, salinity, pressure) and meteorological (wind speed and direction, air temperature, relative humidity, air pressure, irradiance) data collected over a two-year period (2020 – 2021). Seasonal variability is observed in meteorological components, water temperature, and salinity. There is strong seasonal variability in head-mouth temperature and salinity differences. Temperature …
Timing And Magnitude Of Drought Impacts On Carbon Uptake Across A Grassland Biome,
2023
Chapman University
Timing And Magnitude Of Drought Impacts On Carbon Uptake Across A Grassland Biome, Andrew Felton, Gregory R. Goldsmith
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Although drought is known to negatively impact grassland functioning, the timing and magnitude of these impacts within a growing season remains unresolved. Previous small-scale assessments indicate grasslands may only respond to drought during narrow periods within a year; however, large-scale assessments are now needed to uncover the general patterns and determinants of this timing. We combined remote sensing datasets of gross primary productivity and weather to assess the timing and magnitude of grassland responses to drought at 5 km2 temporal resolution across two expansive ecoregions of the western US Great Plains biome: the C4-dominated shortgrass steppe and …
Models For Predicting Maximum Potential Intensity Of Tropical Cyclones,
2023
South Dakota State University
Models For Predicting Maximum Potential Intensity Of Tropical Cyclones, Iftekhar Chowdhury, Gemechis Djira
SDSU Data Science Symposium
Tropical cyclones (TCs) are considered as extreme weather events, which has a low-pressure center, namely an eye, strong winds, and a spiral arrangement of thunderstorms that produces heavy rain, storm surges, and can cause severe destruction in coastal areas worldwide. Therefore, reliable forecasts of the maximum potential intensity (MPI) of TCs are critical to estimate the damages to properties, lives, and risk assessment. In this study, we explore and propose various regression models, to predict the potential intensity of TCs in the North Atlantic at 12, 24, 36, 48, 60, and 72- hour forecasting lead time. In addition, a popular …
A Methodology For Statistical Mean Wave Climate Regime Characterisation In Oceanic Islands: The Case Of The Southern Coast Of Tenerife,
2023
School of Doctoral and Postgraduate Programs, University of La Laguna, La Laguna, S/C Tenerife, Canary Island, 38200, Spain.
A Methodology For Statistical Mean Wave Climate Regime Characterisation In Oceanic Islands: The Case Of The Southern Coast Of Tenerife, Emilio Megías, Manuel García-Román
Journal of Marine Science and Technology–Taiwan
Oceanic islands of volcanic origin tend to have peculiar characteristics, such as: exposure to many wave directions; grouping in archipelagos; steep coastal slopes; and small coastal shelves. All these features require certain considerations in wave climate studies. These types of studies, when wave spectra are not available and have to be performed with parametric data, can be unreliable without an adequate systematic treatment. In this work we propose a methodology consisting of pre-classification according to the peak period and subsequent separation into different sectors according to the geographical fetch. The island of Tenerife is the case study, and in particular …
Context-Dependent Data-Envelopment-Analysis-Based Efficiency Evaluation Of Coastal Ports In China Based On Social Network Analysis,
2023
School of Business, Nanjing Audit University, Nanjing 211815, Nanjing, P.R. China
Context-Dependent Data-Envelopment-Analysis-Based Efficiency Evaluation Of Coastal Ports In China Based On Social Network Analysis, Yu Yu, Dai-Peng Ma, Guo-Ya Gan
Journal of Marine Science and Technology–Taiwan
An emerging trend in performance evaluation is combining social network analysis methods with data envelopment analysis (DEA) models and using network centrality methods to distinguish DEA results. One study employed an input-oriented variable-returns-to-scale DEA model to address referent decision-making units and the corresponding lambda values to construct a network. This study referenced the literature and improved on the use of DEA weight sets to construct a network. We employed a context-dependent DEA model to delineate multiple effective frontier planes, aggregate the reference set relationships on each frontier plane to construct a network relationship matrix, and assess the influences of the …
Research On Improving The Salary Structure Of Port State Control Officers In Taiwan,
2023
North Taiwan Maritime Affairs Center, Maritime and Port Bureau, Ministry of Transportation and Communications, Keelung 200202, Taiwan
Research On Improving The Salary Structure Of Port State Control Officers In Taiwan, Te-Yi Chang, Wen-Chih Ho, Chung-Ping Liu, Yung-Wei Chen
Journal of Marine Science and Technology–Taiwan
The implementation of port state control (PSC) has been challenging in Taiwan due to the lack of port state control officers (PSCOs), and foreign ships berthing at ports in Taiwan that cannot be effectively inspected. PSCOs of Taiwan are subordinate to the public service system and restrained by the number of personnel by the Executive Yuan. Compared with similar professions, their salaries are significantly different from those of the industry, making recruiting and retaining PSCOs a difficult task. Accordingly, this study improved the salary structure of PSCOs by conducting field interviews with existing PSCOs in Taiwan and applying the Fuzzy-AHP …
Numerical Analysis Of Silencer With A Coiled Tube And Straight Perforated Tube Using Fem,
2023
Department of Mechanicaland Materials Engineering, Tatung University, ROC.
Numerical Analysis Of Silencer With A Coiled Tube And Straight Perforated Tube Using Fem, Min-Chie Chiu, Ho-Chih Cheng
Journal of Marine Science and Technology–Taiwan
Marine diesel engine is essential on a ship, but emits extremely loud noise harmful to human hearing. Therefore, it is mandatory to use silencers to reduce the venting noise of the marine diesel engine. An advanced silencer with a new acoustical element of a curved tube, along with perforated holes, is presented to suppress the noise wave. To predict the silencer's acoustical performance for high-order waves, a finite element model was built using COMSOL. The influence of the silencer's noise reduction ability was investigated by exploring sensitivity using acoustical simulations on COMSOL, regarding the silencer's geometric factors. The results proved …
Abundance And Distribution Of Fish Larvae In The Central Coast Of The Algerian Sea,
2023
National Center for Research and Development of Fisheries and Aquaculture (CNRDPA)
Abundance And Distribution Of Fish Larvae In The Central Coast Of The Algerian Sea, Etsouri Mohamed, Khames Ghollame Ellah Yacine, Seridji Rabea
Journal of Marine Science and Technology–Taiwan
This study was conducted on a seasonal basis in five (5) stations along the central Algerian coast between April 2013 and April 2014 aboard professional fishing boats. Horizontal plankton tows with a WP2-type net were used to collect ichthyoplankton samples. At each station, temperature, salinity, and chlorophyll-a levels were measured. We identified the larvae of 18 species from 11 different families by sorting ichthyoplankton (Clupeidae, Engraulidae, Gobidae, Gonostomatidae, Mugilidae, Myctophidae, Scombridae, Sparidae, Carangidae, Labridae, Blennidae). Redundancy analysis (RDA) was used to determine the relationship between the abundance of harvested larvae and environmental variables. The results show a clear dominance of …
Effects Of Direct Water Injection On The Nitrogen Oxide Emission Characteristics Of Marine Diesel Engines,
2023
Department of Naval Architecture and Marine Engineering, Faculty of Engineering, Alexandria University, Alexandria 21544, Egypt
Effects Of Direct Water Injection On The Nitrogen Oxide Emission Characteristics Of Marine Diesel Engines, Mahmoud Abdelnaser Saadeldin, M. M. Elgoharya, Maged Abdelnaby, Mohamed R. Shouman
Journal of Marine Science and Technology–Taiwan
This study examines the issue of diesel emissions from vehicles and vessels and their impact on environmental degradation with a focus on nitrogen oxide (NOx) emissions and their contribution to air pollution-related deaths worldwide. The novelty of this work is the use of computational fluid dynamics simulations to investigate the effectiveness of water addition for reducing NOx emissions. This study considers two methods of water addition, i.e., injection of water and air into a combustion chamber and mixing of water with fuel before injection. Adding water to air systems at 10% and 20% ratios reduces NOx emissions by 5% and …
Predefined-Time Neural Sliding Mode Control Based Trajectory Tracking Of Autonomous Surface Vehicle,
2023
College of Navigation, Jimei University, Xiamen 361021, Fujian,China
Predefined-Time Neural Sliding Mode Control Based Trajectory Tracking Of Autonomous Surface Vehicle, Han Xue, Shulin Li
Journal of Marine Science and Technology–Taiwan
With the progress and development of modern industry, it is urgent to develop a more general and mature predefined time control theory system for uncertain nonlinear systems and apply it to practical engineering systems. Therefore, a novel predefined-time sliding mode control is designed to improve the slow convergence speed of asymptotically convergent controllers and finite-time convergent controllers affected by the initial state of the system. The proposed control approach is proved to converge from the initial value to the balance position using Jensen's inequality and Liapunov theorem. The proposed control method can deal with the ship motion system having six …
Methanol As An Eco-Environmental Alternative Fuel For Ships: A Case Study,
2023
Department of Naval Architecture and Marine Engineering, Faculty of Engineering, Alexandria University, Egypt
Methanol As An Eco-Environmental Alternative Fuel For Ships: A Case Study, Samar K. Sallam, Mohamed M. Elgohary, Ibrahim S. Seddiek
Journal of Marine Science and Technology–Taiwan
Global emissions of Green House Gases and air pollutants are significantly influenced by shipping. Diesel fuel use for energy production is primarily responsible for these emissions. The substitution of traditional marine diesel oil with methanol as a marine fuel is recommended in this study. Moreover, the methanol-diesel dual-fuel engine's environmental and financial benefits are investigated numerically. A cruise passenger ship named Costa Toscana has been evaluated as a case study. Based on the data, the suggested dual-fuel engine reduces emissions of CO2, NOx, SOx, and PM by 25.7%, 38.46%, 45%, and 45%, respectively, with a cost-effectiveness of 286.5, 6645, 268403.4, …
Collision Risk Prediction For Small Ships In South Korea Via Optimization Of Wireless Communication Period,
2023
Ocean Science and Technology School, Korea Maritime and Ocean University, Busan, South Korea, and Korea Institute of Ocean Science and Technology,, Busan, South Korea
Collision Risk Prediction For Small Ships In South Korea Via Optimization Of Wireless Communication Period, So-Ra Kim, Myoung-Ki Lee, Sangwon Park, Dae-Won Kim, Young-Soo Park
Journal of Marine Science and Technology–Taiwan
Since the emergence of COVID-19, there has been a global surge in demand for marine leisure activities. In Korea, the population using marine leisure has risen approximately 192% to 20,406 people, compared to 6,966 people in the year 2000, indicating a continuous growth over the past two decades.. Maritime transportation has become increasingly intricate worldwide due to the development of increasingly autonomous, larger, and faster ships. To effectively address potential hazards in such complex traffic environments, it is imperative to anticipate future scenarios and respond rapidly. However, small vessels account for the highest proportion of marine accidents, exhibit movements that …
Path Planning Of Uav Navigation Mark Inspection Using A K-Means Clustering Aca,
2023
School of Navigation, Dalian Maritime University, Lingshui Road, Dalian, Liaoning 116031, China
Path Planning Of Uav Navigation Mark Inspection Using A K-Means Clustering Aca, Jiaqi Li, Weifeng Li, Wenting Zhang
Journal of Marine Science and Technology–Taiwan
With increasing speeds and application of artificial intelligence in the shipping industry, unmanned aerial vehicle (UAV) technology has been applied to navigation mark inspections to improve the inspection efficiency and safety. Aimed at the UAV path planning problem of navigation mark inspection, this paper proposes an improved K-means clustering ant colony algorithm (KCACA) to design the shortest route for UAV navigation mark inspections. First, the K-means algorithm and the UAV maximum flight distance were used to cluster the navigation marks, which were then split into several secondary clusters. Each cluster was regarded as an independent traveling salesman problem to be …
Coastal Traffic Safety Index Based On Marine Accident And Traffic Records,
2023
Korea Maritime Transportation Safety Authority, Sejong, Republic of Korea
Coastal Traffic Safety Index Based On Marine Accident And Traffic Records, Joohwan Kim, Sang-Lok Yoo
Journal of Marine Science and Technology–Taiwan
In this study, a comprehensive index for evaluating the degree of coastal traffic safety by simultaneously considering marine accident frequency, severity, and traffic volume was considered. To do so, the concept of Equivalent Property Damage Only (EPDO), which is widely used in the road transportation industry, was benchmarked to assess both frequency and severity of accidents. In addition, the total sailing distance of ships was chosen as a variable to explain traffic volume. Finally, a composite performance indicator called "M-EPDO per nautical mile" was built up, enabling the safety performance score for each type of ships in three criteria: on-board …
Inventory Management In Supply Chains With Consideration Of Transportation And Green Technology Cost Under Progressive Carbon Taxation,
2023
Department of Transportation Science, National Taiwan Ocean University, Taiwan, ROC
Inventory Management In Supply Chains With Consideration Of Transportation And Green Technology Cost Under Progressive Carbon Taxation, Ming-Feng Yang, Min-Der Ko, Hung-Jen Tu, Mengru Tu, Jun-Yuan Kuo, Yen-Ting Chao, Shang-Wei Shih
Journal of Marine Science and Technology–Taiwan
Reducing carbon emissions is an important issue in the global supply chain. Governments have formulated different carbon policies to achieve carbon neutrality or emission reduction, in particular, the carbon tax as a policy provides greater certainty about the potential cost to emitters. The Taiwan government is expected to implement the carbon tax policy in 2024 and does not rule out the inclusion of a progressive mechanism which is more effective than a single carbon tax in curbing high carbon emissions Recent studies have also confirmed that a high level and complete carbon tax could encourage companies to invest in green …
Geohash-Based Arrangement Of Live-Fire Exercise Areas Using Ais,
2023
Future Ocean Information Technology, Jeju, Republic of Korea
Geohash-Based Arrangement Of Live-Fire Exercise Areas Using Ais, Sang-Lok Yoo, Cho-Young Jung
Journal of Marine Science and Technology–Taiwan
Live-fire exercise (LFX) areas at sea threaten the safety of ships, whereas, and indiscriminately abandoned unexploded bombs threaten the lives of fishermen. No statistical or scientific research has been conducted on the appropriate locations for LFX areas. Therefore, this study proposes a method for effectively arranging the LFX areas at sea that considers the safety of passing ships and national security. First, the proposed method classifies ship tracking data collected in the daytime based on the dawn and dusk times of the civil twilight phase. Second, the method uses a Geohash geocoding process to identify whether an LFX area coincides …
