Marine Biology Commons^™

An Mrf Model-Based Study On The Effect Of Fishes Upon The Characteristics Of Flow Field Of An Aquaculture Tank, Xian-Ying Shi, Zheng-Zheng Huang, Meng Li, Yinxin Zhou, Xiao-Zhong Ren, Hang-Fei Liu, Shu-Peng Du

Journal of Marine Science and Technology–Taiwan

The study aims to investigate the effect of fish movement on the flow field in the aquaculture tank of a recirculating water aquaculture system. Herein, based on the Navier-Stokes equations and the RNG k-ε turbulence model, the flow field in the aquaculture tank with fish movement was numerically simulated using the multiple reference frame (MRF) model and compared with the numerical simulation results of the fishless aquaculture tank. The results revealed that the overall mean flow velocity in the tank decreased significantly when the fish swam counter-currently with a fixed trajectory, and the overall mean flow velocity increased slightly when …

Occurrence Of Predation Of Juvenile Chum Salmon (Oncorhynchus Keta) By Chub Mackerel (Scomber Japonicus) And Spotted Mackerel (Scomber Australasicus) In Miyako Bay, Iwate Prefecture, Japan, Kei Sasaki, Miwa Yatsuya, Daisuke Shimizu, Daisuke Ojima, Shinji Komatsu

Journal of Marine Science and Technology–Taiwan

In recent years, chub mackerel (Scomber japonicus) and spotted mackerel (Scomber australasicus) have started migrating to the coastal areas off Iwate Prefecture earlier than they did previously, resulting in a geographic overlap between hatchery-bred juvenile chum salmon (Oncorhynchus keta) released at sea and the occurrence of predatory mackerel. To clarify whether the mackerels prey on the juvenile chum salmon, we captured adult mackerels by angling during the period when these species overlap in Miyako Bay, Iwate Prefecture. After capture, the stomach contents of the mackerel were examined using a combination of visual examinations and DNA metabarcoding analysis. As a result, …

Multi-Chamber Silencer Composed Of Screw-Perforated Tubes And Straight-Perforated Tubes, Tian-Syung Lan, Min-Chie Chiu

Journal of Marine Science and Technology–Taiwan

The use of silencers to reduce noise is mandatory due to severe hearing damage caused by high venting noise in the engine room of ocean-going vessels. While straight and perforated tubes have been used as acoustical elements in traditional silencer design, studies have shown that the acoustical design still requires improvement. To enhance acoustical efficiency, the use of multi-chamber mufflers is proposed composed of screw and perforated tubes. Additionally, a mathematical finite element model built for acoustical simulation using the COMSOL program expedites the analysis of silencers with complicated acoustical elements. A sensitivity analysis of transmission loss concerning the geometric …

Rapid Species Identification Of Meretrix Lusoria And Three Other Meretrix Clams Using Pcr And Rflp Analysis Of The Mitochondrial Coii Gene., Chia-Hsuan Sung, Liang-Jong Wang, Chang-Wen Huang

Journal of Marine Science and Technology–Taiwan

Meretrix clams are among the most economically important species of bivalves in Eastern Asia and Taiwan. In the past, the identification of these hard clams depended on the shell morphology; however, species identification based on shell markings and shapes confuses the taxonomy of the Meretrix genus. The DNA molecular information is useful and can easily identify them accurately and quickly, especially the sequence of mitochondrial DNA. In this study, a PCR method to analyze the mitochondrial cytochrome c oxidase II (COII) gene was developed to rapidly identify of M. lusoria, M. lamarckii, M. lyrata and M. petechialis. Four different species …

Bearing Capacity Factor Characteristics Of Footings On Double-Layered Cohesive Soils, Chao-Ming Chi, Zheng-Shan Lin, Yu-Shu Kuo

Journal of Marine Science and Technology–Taiwan

In this study, the bearing capacity of a surface foundation resting on a double-layered cohesive soil profile was investigated by applying a rotational mechanism and finite-difference numerical simulations. The bearing capacity factor behaviors of a surface footing on double-layered cohesive soils can be classified and illustrated using a characteristic chart. Depending on the soil strata strength ratio and normalized layer thickness, the soil-foundation system can be in the squeezing, factor-increasing, factor-decreasing, or constant factor zones. The results indicated that the trend of the curves in the characteristic chart computed from the asymmetric failure mechanism was in accordance with that of …

Research On Ice Resistance Of Ships Sailing In Floating Ice Floe, Zhixin Xiong, Xinyuan Wu, Yang Li

Journal of Marine Science and Technology–Taiwan

To study the ice resistance of ships in areas with floating ice, the Xuelong 2 icebreaker was simulated. A floating-ice model was established using the discrete-element method, and an ice particle array was generated using MATLAB. The effects of ice coverage and speed on ice drag were studied From the numerical simulation results, it can be seen that there is a certain trend in ice resistance under different ice coverage ranges, which changes with the change of speed.By comparing with the empirical formula and the numerical value of the ship model test, this numerical simulation results are relatively accurate.It also …

The Pre-Processing Of Wt Blade Images By Ss And Bilateral Filter With Machine Learning Frameworks, Joy Iong-Zong Chen, Chien-Yeh Lee, Wien-Chieh Lo

Journal of Marine Science and Technology–Taiwan

This paper discusses the motivation behind turbine migration and addresses the challenges of using NN (neural network) computing systems. Moreover, it focuses on high-dimensional data from WT (wind turbine) blades. The three key aspects addressed in this study are turbine migration, overfitting, and strict feature selection. To evaluate the performance of the machine learning system, the study considers the characteristics of WT blades, specifically the similarity in blade color and the differences in shape. The authors apply pre-processing techniques, in particular a bilateral filter, in conjunction with the SS (selective synthesizer) of blade fouling patterns. The SS method adopts the …

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 Rise Of Terrorism In Africa And What It Means For U.S. Policymakers, Bridget Mary Hughes

Master's Theses

This thesis utilizes three case studies to measure the rise of terrorism in Africa. This qualitative data leads the reader to one ultimate question: what does the rise in terrorism in Africa mean for the United States (U.S.) and U.S. policymakers, National Security academia, students in National Security, if anything at all? The answer is: if civilian and military compounds are being targeted by these violent extremists, as these three case studies demonstrate, it is my recommendation that U.S. policymakers cease sending troops to the African theater and, instead, allocate funding to the citizens and nonprofits of the countries whom …

Key To The Species Of Tortanidae Tortanus Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Tharybidae Neoscolecithrix Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Temoridae Temora Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Subeucalanidae Subeucalanus Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Spinocalanidae Spinocalanus Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Spinocalanidae Monacilla Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Scolecitrichidae Scottocalanus Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Scolecitrichidae Scolecitrichopsis Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Scolecitrichidae Scolecithrix Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Scolecitrichidae Scolecithricella Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Scolecitrichidae Scaphocalanus Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Scolecitrichidae Racovitzanus Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Scolecitrichidae Pseudoamallothrix Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Scolecitrichidae Macandrewella Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Key To The Species Of Scolecitrichidae Lophothrix Occurring In The China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.