• Macromolecular Research
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• v.16 no.4
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• pp.345-352
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• 2008

Poly(lactic-co-glycolic acid) (PLGA) tubes (5 mm in diameter) were fabricated using an electro spinning method and used as a scaffold for artificial blood vessels through the hybridization of smooth muscle cells (SMCs) and endothelial cells (ECs) differentiated from canine bone marrow under previously reported conditions. The potential clinical applications of these artificial blood vessels were investigated using a canine model. From the results, the tubular-type PLGA scaffolds for artificial blood vessels showed good mechanical strength, and the dual-layered blood vessels showed acceptable hybridization behavior with ECs and SMCs. The artificial blood vessels were implanted and substituted for an artery in an adult dog over a 3-week period. The hybridized blood vessels showed neointimal formation with good patency. However, the control vessel (unhybridized vessel) was occluded during the early stages of implantation. These results suggest a shortcut for the development of small diameter, tubular-type, nanofiber blood vessels using a biodegradable material (PLGA).

• Journal of the Society of Naval Architects of Korea
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• v.60 no.5
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• pp.388-396
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• 2023

As the government encourages the replacement of small FRP ships with eco-friendly aluminum ships due to environmental pollution problems, interest and demand for small aluminum ships are increasing. It is known that the vibration and noise of aluminum ships are somewhat vulnerable than that of FRP ships. However, in the process of designing and manufacturing small aluminum fishing boats, vibration and noise are not reviewed. In this study, vibration analysis is performed on three existing aluminum fishing boats, and the vibration characteristics of small aluminum boats are identified. Through this study, we intend to contribute to improving the vibration quality of small aluminum ships.

• Journal of Fisheries and Marine Sciences Education
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• v.5 no.2
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• pp.98-109
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• 1993

By the Article 28 of the Korean Fishing Vessels Act and the Article 47-1 of the Enforcement Ordinance of the Act, fishing vessels over 5 gross tone must be insured the fishing vessels mutual insurance or marine insurance. Therefore the distant-water fishing vessels and vessels registered with Classification Society can be insured to the marine insurance, and non-registered vessels and the small fishing vessels can be insured to the fishing vessels mutual insurance of Fisheries Co-operatives. Moreover, the shipowners of fishing vessels over 5 gross tons to be insured a liability insurance for their crew, and it is to compensate effectively the crewman's accidents prescribed in the Seaman's Act. The shipowner's Liability Insurance to be insured the seaman's Compensation Insurance or the seaman's mutual insurance of the Fisheries Co-operatives and the Protection and Indemnity but they still involve lots of problems to cover the crewman's accidents reasonably. The author's views on the improvement way of the fisheries mutual insurance system are as follows. 1. The size of fishing vessels over 5 gross tons prescribed by the Article 28 of the Fishing Vessels Act must be revised into over 1 gross tons. And the regulations concerning penalties against nonfulfilment of the regulation must be strengthened in order to have legal effectiveness. 2. The level of the government subsidy for the fisheries mutual insurance must be raised up from the large point of view for protection of fishermen. It is concluded that the Government have to take charge of the remutual insurance in order to develop the fisheries mutual insurance system. 3. The mutual insurance system of fish catch have to be executed in order to guarantee the stable income for fishermen on the base of the amount of money by fish catch in the previous year.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.1
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• pp.40-45
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• 2019

Unlike the welded pipes in the primary system of light water nuclear power plants being periodically inspected with in-Service inspection program, relatively small pipes with the outer diameter less than 2 inch have not been regularly inspected to date. However, after several failure reports on the occurrence of critical crack-like defects in small pipes, inspection for the small pipes has been more demanded because it could cause the provisional outage of nuclear power plants. Nevertheless, there's no particular method to examine the small pipes having access limitations for inspection due to various reasons; inaccessible area, excessive radiation exposure, hazardous surrounding, and etc. This study is to develop a reliable inspection technique using torsional and flexural modes of guided wave to detect defects that could occur in inaccessible area. The attribute of guided wave that can travel a long distance enables to inspect even isolated range of the pipe from accessible location. This paper presents a case study of the evaluation test on 3/4" small-bore pipes with guide wave method. The test result demonstrates the crack signal behavior and assures possibility to detect the crack signal in a flexural mode, which is clearly distinguishable from the symmetric structure signal in a torsional mode.

• Korea-Australia Rheology Journal
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• v.20 no.4
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• pp.189-196
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• 2008

The pulsatile flow of blood through a stenosed artery under the influence of external periodic body acceleration is studied. The effect of non-Newtonian nature of blood in small blood vessels has been taken into account by modeling blood as a Casson fluid. The non-linear coupled equations governing the flow are solved using perturbation analysis assuming that the Womersley frequency parameter is small which is valid for physiological situations in small blood vessels. The effect of pulsatility, stenosis, body acceleration, yield stress of the fluid and pressure gradient on the yield plane locations, velocity distribution, flow rate, shear stress and frictional resistance are investigated. It is noticed that the effect of yield stress and stenosis is to reduce flow rate and increase flow resistance. The impact of body acceleration is to enhance the flow rate and reduces resistance to flow.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.14 no.2
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• pp.88-95
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• 2018

In this study, to enhance the seismic performance of nuclear power plants (NPP), a small laminated rubber bearing (LRB) is chosen as a seismic design option of the vulnerable equipment. Prior to the application of equipment base isolation, it is necessary to review the feasibility that the technique contributes enough to the seismic performance of NPP by analysis. At first, some preliminary design of small LRBs for equipment is carried out. Design parameters such as horizontal and vertical stiffnesses, design natural frequencies are checked by calculation and analysis for the four design options considering various upper weights. Performance test of small LRB is to be carried out to verify static performance using the results.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.19 no.2
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• pp.117-129
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• 2023

Hydrogen embrittlement of a pipe is an important factor in hydrogen transport. To characterize hydrogen embrittlement, tensile and fracture toughness tests should be conducted. However, in the case of hydrogen-embrittled materials, it is difficult to perform tests in hydrogen environment, particularly at low temperatures. It would be useful to develop a methodology to predict the fracture toughness of hydrogen-embrittled materials at low temperatures using more efficient tests. In this study, the fracture toughness of API X52 steels in hydrogen at low temperatures is predicted from numerical simulation using coupled finite element (FE) damage analyses with FE diffusion analysis, calibrated by analyzing small punch test data.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.4
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• pp.337-344
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• 2004

A real-time surveillance system of the inshore fishing ground was constructed to identify and detect discrete targets, such as illegal fishing vessels. This paper describes measurements made with a combination of sensors, such as radar, CCTV camera, and GPS receivers, for monitoring the fishing activity of small vessels within the fishing limit zones of the inshore waters. The CCTV camera system was used to confirm detection and to classify the type of target. The location of legal vessels distributed in coastal waters was acquired from each GPS system of ships connected to commercial satellite communication network. The surveillance system was networked via LAN to one host PC with the use of electronic navigational charts (ENC) and a radar link. Radar Target Extractor (RTX) for radar signal processing can be remotely accessed and controlled on existing PC via the internet, from anywhere, at any time. Results are presented that demonstrate the effectiveness of the newly constructed fisheries monitoring system for conducting continuous surveillance of illegal fishing vessels in the inshore fishing ground. The identification of illegal fishing vessels was achieved by comparing radar positions of illegal fishing vessels exceeding the warning limits in the surveillance area with GPS position reports transmitted from legal fishing vessels, and the illegal fishing vessels were marked with red symbols on the ENC screen of a PC. The methods to track the activities of all vessels intruding or leaving the fishing limit zones also were discussed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.119-123
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• 2016

In the coastal area, many kind of vessels are operating and exposed to the various marine accidents. In particular, small-size vessels, which are not equipped with the safety equipment, are in the defenceless state to the marine accidents such as the accident according to vessel's own state caused by the diverse reasons and the collision with the neighborhood vessels and objectives. So it is necessary to resolve these situations through the inexpensive equipment. This paper implements the function that can detect vessel's own motion using Smart Phone. if the motion is over the threshold value assigned, this function decides that the current situation is dangerous for this vessel. So this function informs Smart Phone's ower in the vessel and the control center of this situation. This function can be applied to small-size vessels, such as fishing boating, passenger ship, and leasure boat, which have few the safety equipments, and then improve vessel's safety navigation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.5
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• pp.558-563
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• 2014

In order to reduce the risk of deaths from hypothermia at sea, this paper suggests the performance criteria of life rafts for small fishing vessels less than 20 m in length. In our country, the life rafts are not used and have no performance criteria. This research compared the performance criteria of the domestic, foreign, international standards, and the performance comparison between foreign life rafts and the user-friendly valise prototype(2 & 4 persons) which is developed by this study. As a result, it is considered to be appropriate that ISO 9650-1 can be applied to the life rafts for offshore fishing vessels while a milder criteria can be applied to the life rafts for coastal fishing vessels.