Oceanography Commons^™

Study On The Improved Radiation Boundary Conditions Based On The Quadratic B-Spline Rankine Panel Method, Ming-Chung Fang, Chun-Hsien Wu

Journal of Marine Science and Technology–Taiwan

This study presents a higher-order Rankine source method that is based on a biquadratic B-spline scheme with an improved radiation boundary condition. This method solves flow problems under all conditions, where , including the undercritical condition ( < 0.25); this condition is present when a ship undergoes slow translational motion. The proposed method is thus more flexible than the many Rankine-source models in the literature that are applicable only to the overcritical condition ( > 0.25). Specifically, the improved radiation boundary condition is derived from upstream Seto radiation boundary conditions and by incorporating the Rayleigh damping distribution over a free surface; the improved condition is explicit and efficient for solving flow problems. In evaluations, the proposed method yields accurate solutions for unsteady flows, which are produced by an oscillating, translationally moving submerged singularity. The method is also compared …

Sensitive Analysis Of The Static Response Of Compliant Vertical Access Risers, Fuheng Li, Haiyan Guo, Xiaomin Li, Honglu Gu

Journal of Marine Science and Technology–Taiwan

Compliant vertical access risers (CVARs) are considered as efficient and robust alternative options to achieve cost efficiency and safety. Design uncertainties emerge owing to the limited understanding of the effects of various parameters related to the structural properties and marine loads. In this paper, a reasonable three-dimensional (3D) numerical model of CVAR with internal flow is presented based on the slender rod theory. Accordingly, the finite element method combined with a Newton-Raphson scheme is employed to discretize and solve the equations. A sensitivity analysis is performed to investigate the influence of the structural and external load parameters on the static …

Influence Of Boundary Conditions And Internal Fluid Types On Dynamic Characteristics Of A Deepwater Riser, Lei Guo, Zong-Ming Zhu, Zhong-Jian Pan, Zhi-Ming Guo

Journal of Marine Science and Technology–Taiwan

Deepwater Steel Catenary Riser (DSCR) is the key structure of oil and gas production system in the ocean. To design an optimized DSCR system, the dynamic characteristics of the DSCR are analyzed by setting some different boundary condi-tions and internal fluid types. The main vibration mode of the DSCR is found orthogonal to both mass and stiffness according to the normalization condition of the main mode, and then the regular mode function and the jth order principal stiffness Kpj are obtained. Under different initial conditions, the transverse responses of DSCR represented by regular coordinates under arbitrary excitation are obtained. Then, …

Variance Of Td-Mosaic Dual-Vortex Interactions Between In-Fa And Cempaka (2021) In The North Pacific, Tsorng-Lin Chia, Guang-Yang Pan, Ji-Chyun Liu

Journal of Marine Science and Technology–Taiwan

A study of the different types of dual-vortex interactions or “Fujiwara effects” between two storms is crucial for considerably improving weather forecasts. This study combined remote sensing images, empirical formulas based on the possibility of storm interaction (Liou–Liu formula), and vector addition techniques to accurately analyze In-Fa and Cempaka typhoons and the surrounding weather patterns during the 2021 typhoon season in the North Pacific. Although the distance separating the typhoons In-Fa and Cempaka was 1,800–2,040 km, the influence of middle air flow and a tropical depression (TD) caused a "vector superposition TD-mosaic double-vortex" interaction between the two typhoons. Therefore, this …

Optimal Deployment Of Flood Emergency Response Materials Under Stochastic Demands, Shangyao Yan, Jenn-Rong Lin, Chia-Fu Ku

Journal of Marine Science and Technology–Taiwan

This study aims to develop a planning model for the deployment of flood emergency response materials under stochastic demands. For ease of modeling, a deterministic demand model is first proposed, from which the stochastic model is further extended. These models are used to determine the allocation of materials the transport truck routes and distribution of the stockpiled materials to emergency sites. The models are formulated as multiple integer network flow problems with special side constraints which are characterized as NP-hard in terms of optimization. To solve the complicated stochastic model efficiently, we also develop a solution algorithm based on a …

A Non-Iteration Solution For Solving The Backward-In-Time Two-Dimensional Burgers’ Equation With A Large Reynolds Number, Yen-Shen Chang, Yung-Wei Chen, Chein-Shan Liu, Jiang-Ren Chang

Journal of Marine Science and Technology–Taiwan

This article proposes a noniteration solution based on the Lie-group shooting method (LGSM) to solve the backward-in-time two-dimensional Burgers’ equation with a large Reynolds number. The backward problem is famous for seriously ill-posed cases because the solution is generally unstable and highly dependent on the input data. Small perturbations in the input data, such as random errors inherent to the measurements in the analysis, can cause large oscillations in the solution. To handle a large Reynolds number under long time spans, it is very difficult to integrate towards the time direction. To avoid time integration and numerical iteration, the noniteration …

Polyketides And Terpenes In Marine Microalgae: Ecological Roles And Mechanisms Of Biosynthesis, Yunxuan Xie, Mohammad Elsheikh

Journal of Marine Science and Technology–Taiwan

Marine microalgae comprise a large number of polyketides and terpenes identified to date with highly diverse molecular scaffolds and the biological activities (Kalaitzis et al., 2010). These compounds play significant roles in marine food web and nutraceutical supplementation in marine animals. Compounds of this class are often synthesized by gene clusters with dedicated domains responsible for carbon chain extension and modification. The unique molecular structure of these compounds encourages people to investigate their biosynthetic mechanisms in-depth. In this review, we summarize relevant articles to unravel the shared mechanisms of these compounds to further understand the variety of domain organizations and …

Unbaited Light-Emitting Diode Traps Performance For Catching Orange Mud Crabs, Muhamad Naimullah, Kuo-Wei Lan, Mhd Ikhwanuddin, Adnan Amin-Safwan, Wei-Yu Lee

Journal of Marine Science and Technology–Taiwan

Mud crabs (Scylla spp.) are a vital fishery resource and targeted for a valuable source of income for coastal communities throughout the Indo-Pacific region. Baited traps are a considerable expense in crustacean fishing. Hence, the present study was performed to investigate the catchability of Scylla olivacea in response to light-emitting diodes (LEDs) in captivity and field conditions. We used a new experimental setup in the captivity condition that revealed most S. olivacea were attracted to green, blue, and white LED lights and no attractive effect by red LED lights similar to the controls. Field studies have shown that the catch …

Catch And Effort Standardization For Taiwanese Swordtip Squid Uroteuthis Edulis Fisheries In The Southern East China Sea, Ke-Yang Chang, Yu-Jie Hsu, Tzu-Yun Ching, Cheng-Hsin Liao, Chih-Shin Chen

Journal of Marine Science and Technology–Taiwan

The swordtip squid Uroteuthis edulis is a neritic squid species that is widely distributed within the coastal waters of subtropical and tropical Indo-western Pacific regions. This squid is a commercially important species throughout its distribution range and plays a critical role in marine ecosystems. Stock assessments of the squid in the East China Sea (ECS) are scarce, although it is crucial information for the sustainability of the squid and relevant fisheries. The squid was harvested by various fisheries in the southern ECS, which could restrict methods for catch-effort standardization. In this study, catch-effort data of Taiwanese swordtip squid fisheries in …

Uniform Torsion Analysis Of Composite Shafts Using Point Collocation Method Based On Pascal Polynomials, Chih-Wen Chang, Jyh-Hong Wu, Ying-Ru Lin, Yu-Feng Lin, Nan-Nong Huang

Journal of Marine Science and Technology–Taiwan

Torsion bars are important elements in the marine structure applications. The usage of the composite torsion bars has increased recently because it takes advantage of the different material property of each constituent. The current research focuses mainly on the uniform warping analysis of composite torsion shafts by using the point collocation method (PCM). The PCM is based on Pascal's triangle polynomial expansion and coupled with subdomain technique that is indispensable for the analysis of composite bars. In addition to satisfying the field equation (Laplace equation for warping function) and traction-free boundary condition for each component, the continuity conditions in both …

Local Reinforcement Design And Safety Factor Evaluation Of Elliptical Hatch Of Pressure Hull, Guang-Min Luo, Jun-Wei Chen

Journal of Marine Science and Technology–Taiwan

A pressure hull is the primary pressure-resistant structure of a submarine. To safeguard the compressive strength of such a hull, local structural reinforcement is required for various hatches on the hull. Hatches are commonly reinforced through increasing the thickness of the hull regions around them; alternatively, hatch nozzle walls are connected with stiffened frames to maintain the continuity of reinforced structures. This study focused on a pressure hull with an elliptical hatch. A PD-5500 cylindrical pressure hull was used to design a cylindrical pressure hull structure, and a model of hatch nozzle reinforcement was designed using the Boiler and Pressure …

Effects Of Dietary Lipid, L-Carnitine And L-Lysine Supplementation On The Growth Performance And Body Composition Of Epinephelus Lanceolatus Larvae, Jen-Hong Chu, Yu-Cong Hong, Angela Chien, Shyn-Shin Sheen

Journal of Marine Science and Technology–Taiwan

The effects of different combinations of dietary lipid, L-carnitine and L-lysine on the growth performance and fatty acid profiles of larval grouper Epinephalus lanceolatus were evaluated. Eight treatment diets were formulated based on a 2x2x2 factorial design, namely 5 and 14% dietary oil mixture (3:1 fish oil/soybean oil), 0 and 0.5% L-carnitine and 0 and 2.83% L-lysine. Each diet was randomly assigned to triplicate groups of ten 0.08g E. lanceolatus larvae for 42 days. The grouper larvae fed with diets containing 14% lipid had significantly higher weight gain percentages than those fed with diets containing 5% lipid. The weight gain …

Detecting The Feeding Habitat Zone Of Albacore Tuna (Thunnus Alalunga) In The Southern Indian Ocean Using Multisatellite Remote Sensing Data, Sandipan Mondal, Yang-Chi Lan, Ming-An Lee, Yi-Chen Wang, Bambang Semedi, Wan-Ya Su

Journal of Marine Science and Technology–Taiwan

Remote sensing is an effective method for identifying potential feeding habitat zones. Spatial and temporal distribution patterns of albacore (ALB) tuna were studied using Taiwan longline fisheries data from 2009 to 2014. A generalized additive model (GAM) was used to compile a fishery database and statistically explore the relationship between distribution and environmental factors. Sea surface temperature (SST), sea surface chlorophyll-a concentration (SSC), sea surface salinity (SSS), sea surface height (SSH), mixed layer depth (MLD), and eddy kinetic energy (EKE) were examined. The results indicated SST as the largest contributor on ALB distribution, followed by SSS and SSC. Catches per …

Japanese Consumer Preference For Raw Fish: Best–Worst Scaling Method, Takahiro Sajiki, Yu-Heng Lu

Journal of Marine Science and Technology–Taiwan

Given the declining consumption of fish and shellfish in Japan, it is essential to better understand consumer needs to design policies that increase consumption. Therefore, we clarify the relative degree of importance Japanese consumers place on various attributes of raw fish during purchase based on a questionnaire survey employing best–worst scaling. We find that consumers prioritize freshness, price, taste, appearance, safety, seasonality, ease of cooking and eating, nutrition, origin, wild fish, and effect on natural environment and ecosystem, in that order. Wild fish has unexpectedly low importance, although Japanese consumers conventionally purchase captured fishery products rather than cultured ones. The …

Diel Vertical Distribution Patterns Of Pelagic Fish Larvae In Yilan Bay, Taiwan, Yi-Chen Wang, Su-Chen Tsai, Wen-Yu Chen

Journal of Marine Science and Technology–Taiwan

To study the diel migration distribution of larval fish in an area adjacent to the Kuroshio Current, samples were collected from six depths by using a Motoda horizontal net at a fixed station in Yilan Bay on July 30 and 31, 2007. A total of 591 larval fish were collected and assigned to at least 34 families and 57 species. The first five dominant species were Benthosama pterotum (40.95%), Diaphus B type (12.18%), Callionymidae spp. (8.46%), Gobiidae spp. (6.60%), and Apogonidae spp. (4.0%). The density of larval fish varied across time. The maximum larval density was 1220.34 individuals/1000 m3 at …

Long-Term Variation Of Sea Surface Temperature In Relation To Sea Level Pressure And Surface Wind Speed In Southern Indian Ocean, Sandipan Mondal, Ming-An Lee, Yi-Chen Wang, Bambang Semedi

Journal of Marine Science and Technology–Taiwan

Sea surface temperature (SST) is an essential parameter associated with fish habitat and changes in oceanic conditions. Long-term SST variation in relation to sea level pressure (SLP) and surface wind speed (SWS) was observed based on the National Oceanic and Atmospheric Administration (NOAA) data of southern Indian Ocean. Mean monthly time series showed that February and November were the warmest and coolest months, respectively. Spatial distribution showed that 0°S–30°S was warm with SST of 20°–30°C, which was higher than that at all other places throughout the year. SLP (> 1010 millibar) and SWS (> 12 m/s) were high at 20°S–40°S …

Economic Conditions For New Entrants In Coastal Fishing In Miyazaki Prefecture, Japan, Takahiro Sajiki, Yu-Heng Lu, Norie Nishiguchi, Sonomi Akamine, Masaharu Nishiguchi

Journal of Marine Science and Technology–Taiwan

A significant decrease in the number of fishery workers is be-coming a problem in Japan. For new entrants to become estab-lished in the region, they must be profitable as fishing busi-nesses. Using the case of Miyazaki prefecture in Japan, this paper identifies the economic conditions required to make longline fishing and bottom gillnet fishing profitable by ap-plying the net present value (NPV) method. When operating on 200 days, which is the guideline for new entrants in longline fishing, if the value of investment is less than 44.1% of the minimum required, the investment will not provide positive returns. However, the …

Raw Garlic (Allium Sativum) Improves Nonspecific Immune Responses And Resistance Against Vibrio Alginolyticus Infection In Grouper (Epinephelus Coioides), Huai-Ting Huang, Po-Tsang Lee, Zhen-Hao Liao, Cheng-Ting Huang, Hsiang-Yin Chen, Zhi-Gu Huang, Fan-Hua Nan, Yu-Sheng Wu

Journal of Marine Science and Technology–Taiwan

Garlic contains various nutrients and healthful ingredients. The content of garlic products is closely related to their processing methods, and each compound has specific biological effects. Allicin, a heat labile compound, is considered the most important factor in garlic. Garlic powder is commonly prepared by subjecting raw garlic to thermal processing before being grounded into powder,and it is of interest to compare the biological activity of garlic powder with raw garlic in fish. This study investigated immune effects of raw garlic and garlic powder on groupers (Epinephelus coioides). Although raw garlic and garlic powder did not promote growth performance of …

Asymptotic Numerical Solutions For Second-Order Quasilinear Singularly Perturbed Problems, Chein-Shan Liu, Chih-Wen Chang

Journal of Marine Science and Technology–Taiwan

For a second-order quasilinear singularly perturbed problem under the Dirichlet boundary conditions, we propose a new asymptotic numerical method, which involves two problems: a reduced problem with a one-side boundary condition and a novel boundary layer correction problem with a two-sided boundary condition. Through the introduction of two new variables, both problems are transformed to a set of three first-order initial value problems with zero initial conditions. The Runge–Kutta method is then applied to integrate the differential equations and to determine two unknown terminal values of the new variables until they converge. The modified asymptotic numerical solution satisfies the Dirichlet …

Simulation Of A Ship And Tension Leg Platform Wind Turbine Collision, Jiamin Guo, Yu Zhao, Weigang Chen, Guangeng Zhou

Journal of Marine Science and Technology–Taiwan

Collisions between ships and tension leg platform wind turbines (TLPWTs) result in the TLPWT damage, including tower damage and tension leg breakage. This paper details a collision between a ship and TLPWT simulated using the LS-DYNA software package. During simulation, the behaviors of the water around the ship and of the TLPWT were processed using the constant added mass and the fluid–structure interaction methods, respectively. The results indicate that the energy conversion during collision is generally consistent with the law of conversion of energy, suggesting that the simulation’s calculations are acceptable. The TLPWT simulation results imply that two distinct collisions …

The Influences Of Promising Feedstock Variability On Advanced Biofuel Production: A Review, Cherng-Yuan Lin

Journal of Marine Science and Technology–Taiwan

The contribution of biofuels is expected to continuously increase in the global fuel market, as they are environmentally-friendly and provide renewable energy. Four generations of biofuels are categorized and are primarily based on their feedstock sources and the production technologies that are used. The influence of promising feedstock types and the availability on the production technologies and the fuel properties of advanced-generation biofuels are not systematically examined in the literature. Hence, this research extensively reviews the potential impact of feedstock sources and their variability on the production and characteristics of biofuels. The approaches of theoretical analysis and inference referred to …

The Aquatic Particle Number Quandry, Alexander B. Bochdansky, Huanqing Huang, Maureen H. Conte

OES Faculty Publications

Optical surveys of aquatic particles and their particle size spectra have become important tools in studies of light propagation in water, classification of water masses, and the dynamics of trophic interactions affecting particle aggregation and flux. Here, we demonstrate that typical settings used in image analysis vastly underestimate particle numbers due to the particle – gel continuum. Applying a wide range of threshold values to change the sensitivity of our detection system, we show that macrogels cannot be separated from more dense particles, and that a true particle number per volume cannot be ascertained; only relative numbers in relation to …

Dioxins Contamination In Sediment And Their Effect On Accumulation In The Portuguese Oyster (Crassostrea Angulata) And White Shrimp (Litopenaeus Vannamei), Yin-Yu Chen, Yu-Sheng Wu, Hsiang-Yin Chen, Zhen-Hao Liau, Fan-Hua Nan

Journal of Marine Science and Technology–Taiwan

This research aims to realize whether the dioxin accumulation in the oyster and white shrimp which were cultured in the dioxin pollutant sediment. This presented evidence indicated that dioxin was detected in all experimental groups with high concentration accumulated in experiment animals. Observation of the concentration, the PCDD/F, 2,3,7,8-T4CDD was with high concentration in the sediment and declined with the time elapsed. Detection of the dioxin accumulated in the animal, the accumulative maximum amounts was in the oyster as 3746.16 (pg-TEQ/g d.w.) and in the shrimp as 705.44 (pg-TEQ/g d.w.). The detected amount of dioxin in the supernatant was quite …

A Meshless Method With Radial Basis Function For Solving Unsaturated Flow In Heterogeneous Porous Media, Cheng-Yu Ku, Chih-Yu Liu, Wei-Po Huang, Jing-En Xiao

Journal of Marine Science and Technology–Taiwan

This paper presents a study for solving unsaturated flow in heterogeneous porous media using the meshless method with the radial basis function (RBF). For modeling the nonlinear hydrological process in unsaturated zone, an exponential model is introduced in the Richards equation such that we may obtain the linearized Richards equation. We adopt the multiquadric function as the RBF in the meshless method for solving the linearized Richards equation. For simulating the unsaturated flow problems in layered heterogeneous soils, the flux and the head must satisfy the continuity condition at the interface. Several examples are carried out for modeling the hydrological …

Catch Rates And Distribution Pattern Of The Silky Shark, Carcharhinus Falciformis, Caught By The Taiwanese Large-Scale Longline Fishery In The Indian Ocean, Chia Yun Li, Xing-Han Wu, Shang Yin Vanson Liu, Sheng-Ping Wang, Wen-Pei Tsai

Journal of Marine Science and Technology–Taiwan

The silky shark, Carcharhinus falciformis, is widely distributed in tropical and temperate waters, and it is a common bycatch species for tuna longline fisheries. This study examined the distribution of and presents relative abundance indices of the silky shark in the Indian Ocean by using logbook and observer data from the Taiwanese large-scale tuna longline fishery between 2005 and 2019. Due to the high zero catch rate, a zero-inflated negative binomial (ZINB) model was used to standardize catch per unit effort. Due to a lack of detailed targeting information, the fishery strategy was identified by using cluster analysis based on …

Accumulation And Bioavailability Of Heavy Metals (Cadmium, Chromium, Nickel, Lead And Zinc) In Water And Sediment Samples In The Musa Creek, Northwest Coasts Of The Persian Gulf, Saghafiankhoo Sedigheh, Battaleb-Looie Sedigheh, Amanipoor Hakimeh, Dravishi Khatooni Javad, Ghanemi Kamal

Journal of Marine Science and Technology–Taiwan

The current study aimed to investigate the total concentrations of heavy metals in water and sediment samples as well as their bioavailability in sediments of Musa Creek. Twenty samples including 10 sediments and 10 water samples were collected from 10 stations. The concentration of heavy metals was measured using inductively coupled plasma–mass spectrometry. The bioavailability of heavy metals was carried out by first step of Tessier sequential extraction method so called single extraction in the manuscript. The results showed that the mean concentrations of cadmium, chromium, nickel, and zinc in water samples was 0.17, 7.44, 43.80, and 8.85 µg/L, respectively. …

Parametric Analyses Of The Dynamic Response And Fatigue Life Of A Compliant Vertical Access Riser With Internal Flow, Fuheng Li, Haiyan Guo, Xiaomin Li, Zhen Liu, Honglu Gu, Peng Cui

Journal of Marine Science and Technology–Taiwan

Subsea interventions on wellheads can be directly performed from a platform using a compliant vertical access riser (CVAR), thereby incurring tremendous economic benefits. The dynamic response and the fatigue damage of a CVAR subjected to regular waves are important for assessing its application feasibility. Therefore, a reasonable numerical model is presented for assessing the damage to a CVAR considering the internal flow using the slender rod theory. The finite element method combined with a Newmark-β scheme is employed to discretize the equations and update the time integration. The Palmgren-Miner rule is applied for fatigue life prediction, focusing on the wave-induced …

Using The Inverse Method To Investigate Flow Models For Mixed Convection Of Annular Finned Tube Heat Exchanger, Han-Taw Chen, Cheng-Hui You, Wei-Lun Hsu, Jiang-Ren Chang

Journal of Marine Science and Technology–Taiwan

The inverse heat conduction method (IHCM) and three-dimensional (3D) computational fluid dynamic (CFD) in combination with are used to select the appropriate flow model and near-wall treatment for the mixed convection of the annular finned tube heat exchanger. Thus, the numerical results obtained by all k-ε models and near-wall treatments are yielded for 4 m/s ≤ Va ≤ 5 m/s. First, IHCM combined with is applied to estimate and Q values. The obtained estimates of and Q are used as reference values for CFD. The results show that the Tk and results obtained by the standard (STD) k-ε model with …

Prediction Of Remaining Useful Life Of Wind Turbine Shaft Bearings Using Machine Learning, Jinsiang Shaw, Bingjie Wu

Journal of Marine Science and Technology–Taiwan

Wind turbines are a major trend in the current green energy market. Wind energy is abundant, and if utilized properly, can result in significant reductions in carbon emissions. Therefore, the development of wind power systems is urgently required. However, wind turbines are mainly built in unmanned areas. Regular inspections require substantial manpower and material resources, and doubts regarding the accuracy of the inspected data may occur. Therefore, it is necessary to establish an automatic diagnostic method for determining the remaining useful life (RUL) of a wind turbine to facilitate predictive maintenance. In this study, a multi-class support vector machine (SVM) …

Supply Chain Management For Superyacht Construction In Taiwan, Chun Pong Wong

Journal of Marine Science and Technology–Taiwan

In the last 20 years, Taiwan’s superyacht construction industry has performed well in the global market; however, numerous yacht builders still practice traditional supply chain management (SCM), which is often inefficient and regularly leads to time and cost overruns. This study aimed to answer two research questions: 1) what SCM challenges does the superyacht construction industry face? and 2) what SCM strategies and practices should be adopted to improve the efficacy and profitability of superyacht construction companies?

Numerous studies have explored supply chains (SCs) and SCM, but few have focused on the superyacht construction industry. Superyacht construction projects are highly …