• Food Science and Industry
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• v.51 no.4
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• pp.278-301
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• 2018

Although more than 80% of living organisms are found in marine ecosystems, only less than 10% of marine resources have been utilized for human food consumptions and other usages. It is well known that marine resources (fish, shellfish and algae) have exceptional nutritional properties; however, their functional characteristic has not been completely discovered. It is believed that metabolites (organic compounds, proteins, peptides, lipids, minerals, etc.) play an important role to show its biological properties. Marine proteins and peptides are considered to be future drugs due to their excellent biological activities with a fewer adverse side effect. Marine peptides show several biological activities, including antimicrobial, antioxidant, anti-inflammatory, anti-cancer, anti-viral, anti-tumor, anti-diabetic, anti-hypertensive, anti-coagulant, immunomodulatory, appetite suppressing and neuroprotective effects. Therefore, the pharmaceutical, nutraceutical, and cosmeceutical companies have been paid attention to the marine peptides to commercialize into products. This current review mainly focused on the above mentioned biological activities of marine peptides and protein hydrolysates as a functional food and pharmaceutical applications. To commercialize these materials in industrial level required large quantity in high-purity level, and it is complicated to produce huge quantity from the marine resources due to insufficient raw materials, unavailability of raw materials through a year, hinder the growth with geographical variations, and availability of compounds in extreme small quantities. The best solution for these issues is to introduce new modern technologies such as artificial intelligence robots, drones, submersibles and automated raw material harvesting vessels in farming industries instead of man power, which will lead to 4th industrial revolution.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.127-134
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• 2024

With the growth of offshore wind power generation market, the corresponding installation vessel market is also growing. It is anticipated that approximately 100 installation vessels will be required in the of shore wind power generation market by 2030. With a price range of 300 to 400 billion Korean won per vessel, this represents a high-value market compared to merchant vessels. Particularly, the demand for large installation vessels with a capacity of 11 MW or more is increasing. The rapid growth of the offshore wind power generation market in the Asia-Pacific region, centered around China, has led to several discussions on orders for operational installation vessels in this region. The seabed geology in the Asia-Pacific region is dominated by clay layers with low bearing capacity. Owing to these characteristics, during vessel operations, significant spudcan and leg penetration depths occur as the installation vessel rises and descends above the water surface. In this study, using penetration variables ranging from 3 to 21 m, the unique vibration period, structural safety of the legs, and conductivity safety index were assessed based on penetration depths. As the penetration depth increases, the natural vibration period and the moment length of the leg become shorter, increasing the margin of structural strength. It is safe against overturning moment at all angles of incidence, and the maximum value occurs at 270 degrees. The conditions reviewed through this study can be used as crucial data to determine the operation of the legs according to the penetration depth when developing operating procedures for WTIV in soft soil. In conclusion, accurately determining the safety of the leg structure according to the penetration depth is directly related to the safety of the WTIV.

• Journal of Fisheries and Marine Sciences Education
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• v.7 no.2
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• pp.182-200
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• 1995

Thirty two vessels of the Korean purse seiner had been operated in the Western Pacific Ocean for mainly skipjack tuna, Katsuwonus pelmis LINNAEUS and yellowfin tuna, Thunnus albacares BONNATERRE from January to December in 1991. Among them, fourteen vessels were chosen for this research. During the year their daily operated vessels totalled 4,153 vessels, their total casting net were 2,982 times, in caught 1,798 times, and their total catch was 106,300 M/T. We investigate the distribution of their catch by species, by body size, and by surfance water temperature, and also investigate the distribution of their catch by month and section of the sea, where the sections are separated by 30' of longitude and latitude from the monthly operated sea. We summarize these as follows : 1. The rate of catch by species is 75r/o skipjack tunas, 22.3% yellowfin tunas, and 2.7% bigeye and other tunas. 2. Of the caught skipjack tunas, those of weight 2.0~10kg are most and 68%, those of 1.5~8kg are 11.6%, and those of 3.0~8kg are 9.9%. Of the caught yellowfin tunas, those of weight 5~50kg and 10~50kg are most and 23.1%, and 28.3% respectively, those of 20~50kg are 15.8%, weight 30~50kg are 12.5%, and weight 2~50kg are 9.7%. 3. On the distribution of catch by surface water temperature, 49% of catch are taken between $29.0^{\circ}C$ and $29.4^{\circ}C$, 37% are taken between $29.5^{\circ}C$ and $29.9^{\circ}C$, and about 6% are taken between $28.5^{\circ}C$ and $28.9^{\circ}C$, but very little, only about 1% are taken below $28.4^{\circ}C$ and above $30.5^{\circ}C$. 4. On the distribution of catch by month and section of sea, skipjack tunas are most caught 10,618M/T in August and 10,412M/T in September in the section of Lat. $3^{\circ}{\sim}6^{\circ}S$ and Long. $174^{\circ}E{\sim}176^{\circ}W$, caught much 8,825M/I' in June and 8,057M/T in January in section of Lat. $1^{\circ}S{\sim}3^{\circ}N$ and Long. $142^{\circ}{\sim}151^{\circ}$E, but caught very little in May, November and December in the costal area of New Guinea. Yellowfin tunas are mostly caught 4,070M/T in June in the section of Lat. $0^{\circ}{\sim}4^{\circ}$N and Long. $142^{\circ}{\sim}151^{\circ}$E, and caught much over 2,000M/T in February~April and October~December in the section of coastal area and near islands, but caught very little in distant water area.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.6
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• pp.920-926
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• 2010

Marine alga, Chlorella vulgaris, was extracted by chloroform-methanol (2:1, v/v) solvents for lipid extraction at $35^{\circ}C$ for five hours (HCM-35) and its process was compared with conventional lipid extraction condition such as chloroform-methanol (2:1, v/v) at $65^{\circ}C$ for one hour (CM-65). This low temperature extraction process showed that 80% of total lipid was extracted and its residues contained relatively unchanged amounts of intact proteins and other minerals as well as amino acid profiles. Interestingly enough, the weight fraction of carbohydrate in the residues slightly increased due to less denaturation at low process temperature. The biological activities of the residues such as cytotoxicity and immune cell growth activation were not much changed after being extracted. The sensory evaluation were found to be very favorable for being used as a food additive and/or food supplement. This result could also help to maintain the economic feasibility of utilizing marine resources in food and other relevant industries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2951-2957
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• 2015

The development of worldwide harmful algal blooms(HAB) is a serious problem for public health and fisheries industries. To evaluate the algicidal impact on the HAB species, algicide thiazolidinedione derivative (TD49) and yellow clay were examined, which is focus on assess the algicidal effects and inhibition to photosynthesis of HAB species. To obtain the detailed information, we analyzed the viability of target species related to activity Chl. a, photosynthetic efficiency($F_v/F_m$), and electron transport rate(ETR). Culture experiment was conducted to evaluate the algicidal effects of three harmful species(raphidophyceae Heterosigma akashiwo, Chattonella marina, and dinophyceae Heterocapsa circularisquama) and one non-harmful species (cryptophyceae Rhodomonas salina). Our experiments revealed that three HAB species were easily destroyed of the cell walls after TD49 dosing. Also, they had significantly reducing values of active Chl. a, $F_v/F_m$, and ETR, due to the damage of photosystem II by inter-cellular disturbance. As a result, the algicidal effect(%) for the three HABs were as follows, in the order of greatest to the least: H. circularisquama> C. marina> H. akashiwo. However, the algicidal effect for yellow clay remained to be <30% (p>0.01), implying that it may not have damaged the photosystem II. On the other hand, non-HAB R. salina was promoted at both TD49 and yellow clay treatments. Our results demonstrated that the TD49 is a good agent for the control of HABs H. akashiwo, C. marina, and H. circularisquama, whereas the yellow clay would not be suitable for the field application based on our experimental results.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.387-393
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• 2021

In this study, finite element analysis was performed to evaluate a method of increasing the fatigue life of the pipe connection structure commonly used in the topside structure of offshore platforms. MSC Patran/Nastran, a commercial analysis program, was used, and the critical structural model was selected from the global analysis. To realize the stress concentration phenomenon according to the load, modeling using 8-node solid elements was implemented. The main loads were considered to be two lateral loads and a tensile load on a diagonal pipe. To check the hotspot stress at the main location, a 0.01 mm dummy shell element was applied. After calculating the main stress at the 0.5-t and 1.5-t locations, the stress generated in the weld was estimated through extrapolation. In some sections, this stress was observed to be below the fatigue life that should be satisfied, and reinforcement was required. For reinforcement, a bracket was added to reduce the stress concentration factor where the fatigue life was insufficient without changing the thickness or diameter of the previously designed pipe. Regarding the tensile load, the stress in the bracket toe increased by 23 %, whereas the stress inside and outside of the pipe, which was a problem, decreased by approximately 8 %. Regarding the flexural load, the stress at the bracket toe increased by 3 %, whereas the stress inside and outside of the pipe, which was also a problem, decreased by approximately 48 %. Owing to the new bracket reinforcement, the stress in the bracket toe increased, but the S-N curve itself was better than that of the pipe joint, so it was not a significant problem. The improvement method of fatigue life is expected to be useful; it can efficiently increase the fatigue life while minimizing changes to the initial design.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.172-178
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• 2021

In the ship repair market, interest in maintenance and repair is steadily increasing due to the reinforcement of prevention of environmental pollution caused by ships and the reinforcement of safety standards for ship structures. By reflecting this effect, the number of requests for repairs by foreign shipping companies increases to repair shipbuilders in the Southwest Sea. However, because most of the repair shipbuilders in the southwestern area are small and medium-sized companies, it is difficult to lead to the integrated synergy effect of the repair shipbuilding companies. Moreover, the infrastructure is not integrated; hence, using the infrastructure jointly is a challenge, which acts as an obstacle to the activation of the repair shipbuilding industry. Floating docks are indispensable to operating the repair shipbuilding business; in addition, most of them are operated through renovation/repair after importing aging caisson docks from overseas. However, their service life is more than 30 years; additionally, there is no structure inspection standard. Therefore, it is vulnerable to the safety field. In this study, the finite element analysis program of ANSYS was used to evaluate the structural safety of the modified caisson dock and obtain additional structural reinforcement schemes to solve the derived problems. For the floating docks, there are classification regulations; however, concerning structural strength, the regulations are insufficient, and the applicability is inferior. These insufficient evaluation areas were supplemented through a detailed structural FE-analysis. The reinforcement plan was decided by reinforcing the pontoon deck and reinforcement of the side tank, considering the characteristics of the repair shipyard condition. The final plan was selected to reinforce the side wing tank through the structural analysis of the decision; in addition, the actual structure was fabricated to reflect the reinforcement plan. Our results can be used as reference data for improving the structural strength of similar facilities; we believe that the optimal solution can be found quickly if this method is used during renovation/repair.