• International Journal of Naval Architecture and Ocean Engineering
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• v.3 no.1
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• pp.1-8
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• 2011

In this paper, CFD simulation results for a tanker model are compared with experimental data over a range of wave conditions to verify a capability to predict the sea-keeping performance of practical hull forms. CFD simulations are conducted using WISDAM-X code which is capable of unsteady RANS calculations in arbitrary wave conditions. Comparisons are made of unsteady surface pressures, added resistance and ship motions in regular waves for cases of fully-loaded and ballast conditions of a large tanker model. It is shown that the simulation results agree fairly well with the experimental data, and that WISDAM-X code can predict sea-keeping performance of practical hull forms.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.201-201
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• 2010

The evaporative desalination system with solar energy would be the efficient and attractive method to get fresh water. This study was described the development of Multi Effect Distillation(MED) with solar energy desalination system. The system was designed and manufactured Multi effect distillation on the capacity of $3m^3$/day. The experimental apparatus consists mainly of ejector pump, Hot water pump, flow meter, demister, cooler, evaporator and condenser. Evaporator and condenser were made Shell&Tube Heat Exchanger type with corrugated tube. The experimental variables were chosen $75^{\circ}C$ for hot water inlet temperature, 40, 60 and $80{\ell}$/min for hot water inlet volume flow rate, 6.0 and $8.0{\ell}$/min for evaporator feed seawater flow rate, $18^{\circ}C$ for sea water inlet temperature to cover the average sea water temperature and the salinity of sea water is measured about 33,000 PPM (parts per million). for a year in Korea. This study was analyzed the results of thermal performance of Multi Effect Distillation. The results are as follows, The experimental Multi effect distillation is required about 40 kW heat source for production of $3m^3$/day fresh water. Various operating flow rate was confirm in the experiments to get the optimum design data and the results showed that the optimum total flow was $8.0{\ell}$/min. Comparison of Single Effect Distillation with Multi Effect Distillation showed MED is at least more than double of SED.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.3
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• pp.165-173
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• 2008

Sea experiment for this study was carried out to develop a Trawl Escapement Net(TEN) using net material to improve the survival rate of undersized fishes that escaped from trawls in the Korean southern sea in May and November, 2005. Three kinds of Trawl Escapement Net(TEN) were examined to increase the escapement rate for fishes escaped from the TEN, and total catches in the codend and cover-net were investigated. The main catch species in the experimental fishing trials using a V shape TEN(A type) in May were Korean pomfret(Pampus echinogaster), slimy(Leiognathus nuchalis), gizzard shad(Konosirus punctatus), white croaker(Pennahia argentata) and smelt(Sillago sihama). In the experimental fishing trials using a V shape TEN with a protector for undersized fishes(B type) and a panel shape TEN with a protector(C type) in November, the main catch species were horse mackerel(Trachurus japonicus), sea pike (Sphyraena japonica), large-head hairtail(Trichiurus lepturus), kammal thryssa(Thryssa kammalensis), white croaker(Pennahia argentata), butterfish(Psenopsis anomala) and red gurnard(Lepidotrigla microptera). Most of large-sized fish species like Korean pomfret and Spanish mackerel could not escape through the TEN in the B type and C type. Catches of horse mackerel were highest in the experimental fishing of November and escapement rates for most fish species including horse mackerel were higher in the C type compared with B type.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.3
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• pp.372-381
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• 2010

This study was designed to examine the effects of sea buckthorn (SBT) on the plasma blood glucose and cholesterol level in diabetic rats. Diabetes mellitus was induced in male Sprague-Dawley rats weighing 200~220 g by an injection of streptozotocin (STZ) dissolved in a citrate buffer into the tail vein at a dose of 45 mg/kg of body weight. Sprague-Dawley rats were fed an AIN-93 recommended diet and the experimental groups were fed a modified diet containing 10% and 20% of SBT powder for 4 weeks. The experimental groups were divided into 6 groups which consisted of normal (N)-control group, N-SBT 10% and N-SBT 20% treated groups, STZ-control, STZ-SBT 10% and STZ-SBT 20% treated groups. The rats' body weight, aminotransferase activities and hematocrit (Hct) values were measured along with plasma levels of blood glucose and cholesterol. Body weight losses were observed by diabetic groups While the nondiabetic rats gained weight. There were significant differences between the control group and the diabetic groups in the weight of kidney. Aspartate aminotransferase activity was lower in the non-diabetic group compared to diabetic experimental groups. The blood glucose were significantly decreased in the 10% SBT of diabetic group. The cholesterol level of STZ-SBT 10% and STZ- SBT 20% were significantly lower than for the STZ-control group. These results show that the supplementation of sea buckthorn leave powder may have favorable influence on reducing blood glucose and cholesterol level in STZ-induced diabetic rats.

• Hwankyungkyoyuk
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• v.18 no.1 s.26
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• pp.120-133
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• 2005

This study investigated the changes of consciousness and ambivalent attitudes about the important environmental issues among the teachers who enrolled the environmental education training. Experimental and control groups were composed with 47 and 30 person, respectively. Environmental issues were constructions of sea-wall, nuclear power plant and dam. Cronbach alpha of the self-developed questionnaire was $0.6909{\sim}0.8992$. Score were made with 5 Likert scales for consciousness, and with semantic differential half scale for ambivalent attitudes. Almost teachers(94.0% and 97.1%) have above 10 years teaching career. Strangers in environmental program were 53.2%. After environmental training, teachers' consciousness was significantly changed to negative about the construction of sea-wall for the farm field and industry complex area(p=0.019), and about the construction of dam for disaster like flood(p=0.026), and for adverse effects of citizen by fog(p=0.042). They were also significantly changed to negative about the construction of nuclear power plant for economical energy(p=0.004)', no-emission of greenhouse gases(p=0.033)', 'alternative energy(p=0.000)', 'destruction of ecology(p=0.052)' and 'social fear(p=0.009)'. The consciousness of teachers who have the experience of environmental training, were significantly changed to negative about the construction of nuclear power plant. Scores of teachers' ambivalent attitudes were made lower in experimental than control group about the construction of sea-wall and nuclear power plant. After education training, they were made lower so much as -10.0% in control, but higher much as +4.4% in experimental, and severely higher much as 86.5% in teachers who had experienced the environmental training about construction of sea-wall. Their scores were made lower so much as -3.3% in control, but much as -6.4% in control.

• ALGAE
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• v.34 no.3
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• pp.217-228
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• 2019

The marine brown algal genus Colpomenia has a worldwide distribution, with five species reported in Korea and Japan. However, no studies to date attempted to identify the number of species and geographical distribution of Colpomenia along Chinese coast. To fill the biodiversity knowledge gap, we analyzed 63 mitochondrial cox3 and 62 mitochondrial atp6 sequences of Colpomenia specimens collected from 30 localities along the Chinese coast. Maximum likelihood and Bayesian inference trees suggest the presence of at least three Colpomenia species (i.e., C. peregrina, C. claytoniae, and C. sinuosa) in China. C. peregrina and C. claytoniae are documented for the first time. C. sinuosa was only found in the South China Sea and its distribution didn't overlap with that of C. peregrina which was found in the Yellow-Bohai Sea and the East China Sea. C. claytoniae appears to be confined to three isolated islands in the East and the South China Sea, where it occurs in sympatry with, respectively, C. peregrina and C. sinuosa. Future study can focus on comparing eco-physiological differences of Colpomenia species in response to environmental variables and exploring possible genetic hybridization / introgression at inter-specific contact zones.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.99-108
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• 2023

In this study, changes in biofloc-related and pathogenic bacteria in both low and high concentration biofloc breeding water planted with the halophyte (Triglochin maritimum were investigated). In the low-concentration biofloc breeding water, the ratio of bacteria related to the nitrogen cycle was initially 59.57% and, it decreased to 26.57% at the end of the experiment while other bacteria (excluding nitrogen-cycling bacteria and vibrios) increased from 38.75% to 73.43%. However, the planted experimental group maintained a relatively high ratio of nitrogen cycling bacteria at 58%. In the high-concentration experimental group, bacteria related to the initial nitrogen cycle, non-pathogenic vibrios, and pathogenic vibrios were 11.60, 36.28, and 20.14%, respectively. Finally, nitrogen-cycling bacteria were 36.47% in the control group and 37.55% in the planted group. The total number of vibrios decreased by 46.54% in the planted group and 48.01% in the control group, indicating a significant decrease in both experimental groups. However, the residual rate of pathogenic vibrios was 4.48% in the control group and 0.54% in the planted group. Overall, the planted group showed decreasing harmful bacteria and increasing useful bacteria.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1753-1762
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• 2017

Sea cucumber (Apostichopus japonicus) is a popular seafood source in Asia, including South Korea, and its consumption has recently increased with recognition of its medicinal properties. However, because raw sea cucumber contains various microbes, its ingestion can cause foodborne illness. Therefore, analysis of the microbiota in the whole body of sea cucumber can extend our understanding of foodborne illness caused by microorganisms and help to better manage products. We collected 40 sea cucumbers from four different sites in August and November, which are known as the maximum production areas in Korea. The microbiota was analyzed by an Illumina MiSeq system, and bacterial amounts were quantified by real-time PCR. The diversity and bacterial amounts in sea cucumber were higher in August than in November. Alpha-, Beta-, and Gammaproteobacteria were common dominant classes in all samples. However, the microbiota composition differed according to sampling time and site. Staphylococcus warneri and Propionibacterium acnes were commonly detected potential pathogens in August and November samples, respectively. The effect of experimental Vibrio parahaemolyticus infection on the indigenous microbiota of sea cucumber was analyzed at different temperatures, revealing clear alterations of Psychrobacter and Moraxella; thus, these shifts can be used as indicators for monitoring infection of sea cucumber. Although further studies are needed to clarify and understand the virulence and mechanisms of the identified pathogens of sea cucumber, our study provides a valuable reference for determining the potential of foodborne illness caused by sea cucumber ingestion and to develop monitoring strategies of products using microbiota information.

• Journal of Environmental Science International
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• v.18 no.10
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• pp.1171-1179
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• 2009

The solitary ascidian, Halocynthia aurantium, which is commonly called the sea peach because of its coloration and general shape, is a valuable organism of benthic marine population in the northern region of the East Sea, Korea. It is seldom found at a depth of less than 10 meters and the sea peach is frequently observed in large populations between 20 and 100 meters. It appears to prefer attachment to vertical rocks faces and artificial cement blocks exposed to the currents. Mass mortality and reduction of resources in sea peach, H. aurantium, were occurred in the benthic area of the northern region of the East Sea because of the rapid fluctuation of environmental factors such as temperature and salinity due to mass rainfall in summer and going up north of a strong warm current in winter. Therefore, we examined the effects of temperature and salinity on embryonic development of fertilized eggs, tadpole larva to metamorphosis, and attachment to siphon development. Laboratory-raised larvae were studied using a two-factorial experimental design with four levels of temperature(8, 12, 16 and $20^{\circ}C$) and four levels of salinity(20, 25, 30 and 34 psu). The ascidian larvae of H. aurantium survived environmental conditions between temperature of $8{\sim}20^{\circ}C$ and salinity of 25~34 psu and exhibited positive growth at $8{\sim}16^{\circ}C$ and 30~34 psu. Fertilized eggs have not developed at lower salinity of 20 psu irrespective of temperature range tested and have showed an abnormal development at the salinity of 25 psu between higher temperatures of 20 and $24^{\circ}C$. This result suggests that temperature increase and salinity reduction depending on environmental fluctuation may have significant impacts on population variation of H. aurantium in the northern region of the East Sea.

• Preventive Nutrition and Food Science
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• v.5 no.4
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• pp.219-224
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• 2000

Dieary effects of sea tangle on immune functions were investigated in diabetic mice. Four groups of ICR mice weighing 33.36$\pm$1.01 g were fed either an AIN-76 diet only (control), or with additional sea tangle powder, sea tangle water extract, and alginate at the level of 13.6%, 4%, and 1%, respectively by weight. Cellulose was omitted in sea tangle powder and alginate diets. After 10 days of feeding respective experimental diets, all mice were made diabetic by five consecutive intramuscular injections of streptozotocin (40mg/kg body weight per day) and fed the diets for four more weeks. Plasma IgG concentrations but not those of IgM were significantly higher in mice fed sea tangle powder, extract or alginate than those on the control diet. Plasma TNF$\alpha$ levels were, however, lower in those fed sea tangle power or water extract than control and alginate fed groups. TNF$\alpha$ releases from macro phages isolated from four groups and cultured with 5 $\mu\textrm{g}$/mL LPS for 24 hors showed a similar tendency to the results of plasma concentrations in the respective groups, but IL-1$\beta$ releases were not different among four groups. Lymphocyte proliferation in response to LPS (10$\mu\textrm{g}$/mL) measured using splenocytes cultured for 3 days was highest in the alginate fed group (594$\pm$38%) and those of sea tangle powder (536$\pm$47%) and extract (547$\pm$34%) fed groups tended to be higher than the control (523$\pm$30%). It is concluded that sea tangle contains immunomodulatory components besides alginate that could enhance humoral immunity of itself. The immunomodulatory effects of sea tangle constituents is regarded as beneficial for diabetic subjects.