• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.36-43
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• 2024

Fishing net waste (FNW) constitutes over half of all marine plastic waste and is a major contributor to the degradation of marine ecosystems. While current treatment options for FNW include incineration, landfilling, and mechanical recycling, these methods often result in low-value products and pollutant emissions. Importantly, FNWs, comprised of plastic polymers, can be converted into valuable resources like syngas and pyrolysis oil through pyrolysis. Thus, this study presents a process for generating high-purity hydrogen (H₂) by catalytically pyrolyzing FNW in a CO₂ environment. The proposed process comprises of three stages: First, the pretreated FNW undergoes Ni/SiO₂ catalytic pyrolysis under CO₂ conditions to produce syngas and pyrolysis oil. Second, the produced pyrolysis oil is incinerated and repurposed as an energy source for the pyrolysis reaction. Lastly, the syngas is transformed into high-purity H₂ via the Water-Gas-Shift (WGS) reaction and Pressure Swing Adsorption (PSA). This study compares the results of the proposed process with those of traditional pyrolysis conducted under N₂ conditions. Simulation results show that pyrolyzing 500 kg/h of FNW produced 2.933 kmol/h of high-purity H₂ under N₂ conditions and 3.605 kmol/h of high-purity H₂ under CO₂ conditions. Furthermore, pyrolysis under CO₂ conditions improved CO production, increasing H₂ output. Additionally, the CO₂ emissions were reduced by 89.8% compared to N₂ conditions due to the capture and utilization of CO₂ released during the process. Therefore, the proposed process under CO₂ conditions can efficiently recycle FNW and generate eco-friendly hydrogen product.

• Journal of the Korean earth science society
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• v.41 no.5
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• pp.504-519
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• 2020

Oceanic fronts, which are areas where sea water with different properties meet in the ocean, play an important role in controlling weather and climate change through air-sea interactions and marine dynamics such as heat and momentum exchange and processes by which properties of sea water are mixed. Such oceanic fronts have long been described in secondary school textbooks with the term 'Jokyung water zone (JWC hereafter) or oceanic front', meaning areas where the different currents met, and were related to fishing grounds in the East Sea. However, higher education materials and marine scientists have not used this term for the past few decades; therefore, the appropriateness of the term needs to be analyzed to remove any misconceptions presented. This study analyzed 11 secondary school textbooks (5 middle school textbooks and 6 high school textbooks) based on the revised 2015 curriculum. A survey of 30 secondary school science teachers was also conducted to analyze their awareness of the problems. An analysis of the textbook contents related to the JWC and fishing grounds found several errors and misconceptions that did not correspond with scientific facts. Although the textbooks mainly uses the concept of the JWC to represent the meeting of cold and warm currents, it would be reasonable to replace it with the more comprehensive term 'oceanic front', which would indicate an area where different properties of sea water-such as its temperature, salinity, density, and velocity-interact. In the textbooks, seasonal changes in the fishing grounds are linked to seasonal changes in the North Korean Cold Current (NKCC), which moves southwards in winter and northwards in summer; this is the complete opposite of previous scientific knowledge, which describes it strengthening in summer. Fishing grounds are not limited to narrow coastal zones; they are widespread throughout the East Sea. The results of the survey of teachers demonstrated that this misconception has persisted for decades. This study emphasized the importance of using scientific knowledge to correct misconceptions related to the JWC, fishing grounds, and the NKCC and addressed the importance of transferring procedures to the curriculum. It is expected that the conclusions of this study will have an important role on textbook revision and teacher education in the future.

• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.1-13
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• 2012

We diagnosed on status and problems of environmental assessment regarding development of offshore wind power, and also on reasonable core assessment items. Most of the coastal wind power are located on the western coastline of Korea and Jeju Island. In the selections of the site for the offshore wind farms, a previous investigations should be conducted with regard to distances from the land, stabilities from external forces (tide, wave, etc.) and topographical changes, and characteristics of the surroundings (distributions of protected area, fishing ground, artificial seagrasses, and shipping traffic). It is needed to assess dispersion of suspended solids, changes of the sea bottom, and impacts on fisheries resources and fishing activities under construction of offshore wind power. Furthermore, the responses of marine organisms to noise and vibration, impacts by electromagnetic fields, impacts on sea birds, hindrances to sea lane routes, and damaged scenery and marine protection areas are thoroughly assessed during operation processes. The consultation criteria in case of development of offshore wind farm is adjusted by focusing marine environmental impact assessment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.3
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• pp.301-310
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• 2013

To suggest a standard concerning with the arrangement of bridge equipment, the authors conducted the video observations with 3CCD (charge coupled device) cameras installed on the ceil of the bridge for monitoring the working activities of two bridge teams (the skipper/mate1 and the skipper/mate2) in a Korean coastal large trawler(gross tonnage: 139) for five days from July 30th. 2010 and analyzed of the data. Work elements coded by the work activities were input on the sheet of work analysis by the time unit of 1 sec according to the time occurred. A single work element among the work activities for every 5 minutes was denoted as the number of occurrence. The frequency of equipment usage was limited only in the usage of the equipment. In the case of the navigation and the towing net two ranks were integrated and analyzed. On the other hand, in the case of the casting net and the hauling net, two processes were integrated to as one and then analyzed separately as two ranks. As the results, 15 elements of work was carried out between two bridge teams for the observation; lookout, radar, GPS plotter, fish finder, net monitor, fishing deck, RPM indicator, rudder angle indicator, compass card, for maneuver; steering, ship speed control, trawl winch operation and external communications, paper works and others. It was found that the work load of the skipper per 5 minutes accordance with the navigation, the casting net, the towing net and the hauling net are 20.5 times, 11.9 times, 38.0 times and 9.5 times respectively, the mates are 65.2 times, 66.5 times, 85.7 times and 59.1 times respectively. The radar was shown the highest frequency of the equipment usage and the next was the fish finder, the GPS plotter and the external communications in the case of the navigation. In the case of the towing net the frequency of usage was high the ranking as the radar, the net monitor, the fish finder, the GPS plotter, the steering system and the external communications. In the case of the integrated process both of the casting and hauling net the trawl winch was shown the highest frequency to the skipper and the next was the GPS plotter and the radar, and the steering system was shown the highest frequency to the mate and the next was the radar, the ship speed control system, the GPS plotter, the net monitor and the fish finder.

• Ocean and Polar Research
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• v.23 no.4
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• pp.411-417
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• 2001

Due to international law the Antarctic is currently the best protected large ecosystem on earth, providing the opportunity for scientific research into processes of both regional and global importance. However, it is impossible to carry out research activities without minor disturbances to the environment. The Weddell Sea with its shelf inhabiting fauna can be considered to be representative for the entire Antarctic shelf with exceptions. It has generally escaped major anthropogenic impact but it is the only area in the high latitude Antarctic where long-term research fishing has been carried out. There are two main results combining aspects of nature conservation and benthos research. Firstly, the use of dredges has clearly decreased over the last two decades, whilst the use of non-invasive underwater photography and video has significantly increased. Secondly, during the same period icebergs destroyed an area of the seafloor and its fauna more than 2000-times greater than the area affected by research trawls. The increased use of imaging methods, Remotely Operated Vehicles (ROV) and other modem instruments, as well as statistically based and coordinated sampling strategies can contribute to both a better understanding of ecosystem function and to an ongoing reduction in anthropogenic impact.

• Journal of the Korean Society of Industry Convergence
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• v.16 no.2
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• pp.41-46
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• 2013

On the purpose of helping the inhabitants living in farming, fishing villages, and islands for more safe and hygienic water from simple waterworks, experimental investigations were performed concerning the development of a water purifier with silver nanomaterial packed, having a function of the auto-disinfection. The results show as follows through such filteration and auto-disinfection processes. It is possible to get hygienic and safe water, for example, more than 95% of general bacteria, total coliforms, and fecal coliforms were removed. It is also possible to get good-quality water, for 49.4% of spent potassium permanganate and 85% and 63% of turbidity and conductivity were removed respectively. It is a very effective equipment, for 100% cost reduction of used chemicals was achieved by no-chemical disinfection process and THM was not generated.

• The Journal of Fisheries Business Administration
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• v.25 no.2
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• pp.1-46
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• 1994

The Purpose of this research is to analyze and discuss the development of yellowtail aquaculture industry in Japan and its management structure. The research includes the following : (a) It confirms the industrial conditions of yellowtail aqaculture which has a national technical and mass production system that has been developed at great speed. (b) It analyzes yellowtail aqaculture development from a family - oriented management to a large scale production. (c) It examines how the fisheries cooperatives harmonized their role with the object of individual aqaculture management and aqaculture fishing ground management. The reasons for this study focusing on the yellowtail aqaculture industry of Japan are : (a) The yellowtail aqaculture is regared as a typical field in aqaculture because it reflects the general aqaculture history, quantity of fisheries aqaculture product, the number of fishermen involved in this industry, technology , and the live and fish market formation in Japan. (b) The aqaculture has the most powerful entrepreneurial in financial and management style. The aqaculture industry also has a most individual management style which includes planned production and shipping strategy. This research has attempted to study the industrial processes of fisheries aqaculture industry and its management development, and focused on the yellowtail aqaculture industry of Japan. This work also includes data about the aqaculture management of fisheries cooperatives and case by case analysis of aqaculture production. The following results were obtained from this study : First, even though ocean, weather conditions, and widespread propagation of places suitable for aqaculture in Japan were crucial factors in aqaculture development, it must be pointed out that fisheries policy in Japan changed from "catching" in the 1960s to "cultivating". Second, the widespread course of fisheries cultivating technology in Japan has had two characteristics. One is that early aqaculture technology spread to the southern part of Japan and the other is that the metal nets were widely used in the northern part in the 1970s. Japan's yellowtail aqaculture industry's overproduction was due to metal nets. However, the use of mwtal nets also contributed to the improvement of aqaculture and the strategic aspects of aqaculture management. In addition, it should be stressed that Kagoshima prefecture as the pioneer of metal nets contributed to fisheries aqaculture development in japan. Third, as aqaculture technology developed, entrepreneurial qualities of aqaculture management also developed this field into a large scale business. Even though it is not clear, large scale management of yellowtail aqaculture shows evidence of superiority over small andmedium - size management of yellowtail aqaculture. Fourth, yellowtail aqaculture management in Japan hascontributed to the production system and aqaculture strategy to meet consumers' needs and market demands from weather - oriented trational fisheries industry, which overcame their overproduction structure. Fifth, Japanese fisheries cooperative played very important roles in the prevention of fishing grounds production from destruction and in promoting suitable aqaculture facilities so that aqaculture could grow continually.ld grow continually.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.155-166
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• 1999

The construction of the coastal structures and reclamation work causes the circulation reduced in the semi-closed inner water area and the unbalanced sediment budget of beach results in an alteration of beach topography. Among the various fluid motions in the nearshore zone water particle motion due to wave and wave-induced currents are the most responsible for sediment movement. Therefore it is needed to predict the effect of the environmental change because of development and so the prediction of wave transformation dose. The purpose of this study is to introduce the relation between waves wave-induced currents and sediment movement. In this study we will show numerical method using energy conservation equation involving reflection diffraction and reflection and the surfzone energy dissipation term due to wave breaking is included in the basic equation. For the wave-induced current the momentum equation was combined with radiation stresses lateral mixing and friction Various information is required in the prediction of wave-induced current depending on the prediction tool. We can predict changes in wave-induced current from the distribution of wave especially near the wave breaking zone. To evaluate these quantities we have to know the local condition of waves mean sea level and so on. The results from the wave field and wave-induced current field deformation models are used as input data of the sediment transport and bottom change model. Numerical model were established by a finite difference method then were applied to the development plan of the eastern Pusan coastal zone Yeonhwa-ri and Daebyun fishing port. We represented the result with 2-D graphics and made comparison between before and after development.

• The Journal of Fisheries Business Administration
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• v.51 no.2
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• pp.71-87
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• 2020

Oysters are the most abundantly harvested type of shellfish in Korea. As export of this marine product increases, oysters have greatly contributed to an increase in fishing income. As the oyster aquaculture industry has rapidly grown since the late 1990s, issues of oyster-shell processing that occur in production processes have re-emerged as important topics in the oyster industry. The amount of oyster shells harvested in 2019 is estimated to be approximately 300,000 tons. With reductions in demand for pyrolytic fertilizer and feed, which are currently the greatest sources of demand, unprocessed shell quantities have doubled compared to 2018, causing them to be an issue once more. Such oyster-shell processing also incurs great costs, and a total of forty-six billion three hundred fifty million Korean won (46,350,000,000 KRW) has been provided from 2009 to 2020 for the use of oyster shells as a resource. According to current Korean laws, oyster shells are considered to be industrial waste if more than 300 kilograms are sent out in a day. Collection and processing must be conducted by a waste-consignment company. Consequently, there are many limitations to the use of oyster shells in Korea as a resource. However, in Japan, only oyster-shell waste is regulated by waste-processing As a result, local governments may apply exceptions when utilized as organic matter. Consequently, in Japan, oyster shells are being used as resources in more diverse fields than in Korea. This study observes the conditions and problems of oyster-shell processing in Korea and attempts to find new domestic oyster-shell resource solutions in light of Japan's recycling practices.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.387-394
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• 2016

Today, hot rolled mill plant are currently operating 24 hours a day. The main processes of hot-rolled steel mill are Reheating Furnace, Roughing Mill, Fishing Mill and the Down Coiler. In the process checking over the thickness and width of rolled material, temperature control is an important factor. It is quite often the cause of the work breakdown and find a bad elements for product. After the shipping out the product, when a claim occurs requires an investigation. In each process of the conventional thickness gauge, width, and thermometer. Operation by an independent data acquisition and this monitoring is problematic and straining of the operator. The monitoring process the data of each function and incorporate monitoring results can also check future work. The installation of this system will improve our efficiency and productivity. In the rolling process by developing more efficient operating quality monitoring system, this will be made possible.