• Title/Summary/Keyword: Sea State

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Laboratory Study on the Settling Properties of Silty Mud (실트질 점토의 심강(沈降) 특성(特性)에 관한 연구)

  • Kim, Cha Kyum;Lee, Jong Sup
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.11 no.3
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    • pp.85-93
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    • 1991
  • To investigate the effect of the initial sediment concentration ($C_o$) and bed shear stress (${\tau}_b$) on the settling properties of silty mud, deposition experiments were conducted in a recirculating flume using silty mud sediment taken from the Youngkwang coast which is located in the eastern Yellow Sea. The relative concentration, $C/C_o$ (C=depth averaged concentration), and the relative equilibrium concentration, $C_{eq}/C_o$ ($C_{eq}$=depth averaged concentration in the equilibrium state), have been found to depend much more strongly on the bed shear stress than initial concentration, and to increase with increasing bed shear stress. The minimum value. ${\tau}_{bmin}$, and maximum value. ${\tau}_{bmax}$, of critical bed shear stress for deposition of the Youngkwang sediment were deduced to be $0.017N/m^2$ and $1.25N/m^2$, respectively, and these values depend strongly on the properties of sediment (grain size and mineralogy). Formulas for the relative concentration and apparent median settling velocity in the range of ${\tau}_b{\geq}{\tau}_{bmin}$ were deduced. The apparent median settling velocity was found to depend much more strongly on the bed shear stress than the initial concentration and to decrease exponentially with increasing bed shear stress.

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Characteristics of Tropical Cyclones over the Western North Pacific in 2008 (2008년 태풍 특징)

  • Cha, Eun-Jeong;Hwang, Ho-Seong;Yang, Kyung-Jo;Won, Seong-Hee;Ko, Seong-Won;Kim, Dong-Ho;Kwon, H. Joe
    • Atmosphere
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    • v.19 no.2
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    • pp.183-198
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    • 2009
  • The purpose of this study is to summarize the tropical cyclone (TC) activity of 2008 over the western North Pacific including the verification of the official track and intensity forecast errors of these TCs. The TC activity - frequency, Normalized Typhoon Activity (NTA), and life span - was lower than 58-year (1951-2008) average. 22 tropical cyclones of tropical storm (TS) intensity or higher formed in the western North Pacific and the South China Sea in 2008. The total number is less than 58-year average frequency of 26.4. Out of 22 tropical cyclones, 11 TCs reached typhoon (TY) intensity, while the rest 11 TCs only reached severe tropical storm (STS) and tropical storm (TS) intensity - six STS and five TS storms. One typhoon KALMAEGI (0807) among them affected the Korea peninsula. However, no significant impact - casualty or property damage - was reported. On average of 22 TCs in 2008, the Korea Meteorological Administration (KMA) official track forecast error for 48 hours was 229 km. There was a big challenge for individual cyclones such as 0806 FENGSHEN and 0817 HIGOS presenting significant forecast error, with both intricate tracks and irregular moving speed. The tropical cyclone season in 2008 began in April with the formation of NEOGURI (0801). In May, four TCs formed in the western North Pacific in response to enhanced convective activity. On the other hand, the TC activity was very weak from June to August. It is found that the unusual anti-cyclonic circulation in the lower level and weak convection near the Philippines are dominant during summertime. The convection and atmospheric circulation in the western North Pacific contributed unfavorable condition for TC activity in the 2008 summertime. The 2008 TC activity has continued the below normal state since mid 1990s which is apparent the decadal variability in TC activity.

Naval Warfare and the Development of the Weapon System in History (역사속 해전과 무기체계 발달양상)

  • Kim, Jeong-hyun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.05a
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    • pp.144-150
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    • 2013
  • From ancient times to the present day, naval warfare in history is deeply connected with the rise and fall of countries. This study examines which countries won wars by tracing naval warfare that they had carried out. Seven Cases are traced for the analysis including the battle of Salamis and the Poeni War in the ancient period, the battle of Calais in the medieval and modern periods, the Russo-Japanese War in the modern period, and the Falklands War in the present age. The results show three fundamental characteristics. First, countries that won naval warfare were armed with the state-of-the-art weapon systems and conducted joint operations effectively. Second, countries that fought in the usual ways were defeated by challengers. Third, countries such as Athens, Rome, Britain and the United States ascended to the hegemony by winning major naval warfare and then commanding or controlling the sea at their own free will. Countries defeated in these naval warfare, however, descended to the weak powers. In general, countries that won warfare have a tendency to make light of defeated countries, not to introduce new weapon systems from abroad, and to stick to their traditional ways of fighting. These lessons indicate that the ROK military needs to continue the development of new weapon systems at peacetime. In addition, they show that it needs to focus more on the articulation of military doctrines and training systems so that warriors on the battlefield can fight better.

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Effects of Eisenia Bicyclis Extracts and Pill on Blood Glucose and Lipid Profile in Streptozotocin-Induced Diabetic Mice (당뇨 생쥐에서 대황 추출물 및 정제환의 혈당과 지질 상태 개선 효과)

  • Cho, Sung-Hee;Park, So-Young;Choi, Sang-Won
    • Journal of Nutrition and Health
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    • v.41 no.6
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    • pp.493-501
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    • 2008
  • The objectives of this study were to investigate the antihyperglycemic and hypolipidmic effects of sea oak(Eisenia bicyclis, EB) in the diabetic state and to examine the appropriateness of formulated EB pill for the effects. The various test materials obtained from EB were included in the experimental diets with 15% fat/0.5% cholesterol and fed to streptozotocin-induced diabetic mice weighing $35.0{\pm}0.7$ g for three weeks but not in the control diet having the same composition. The test materials were EB dry powder, water and ethanol extracts, viscozyme-treated EB water extract(EB enzyme-TR) and formulated pill containing dry powders of the EB, two kinds of seaweed, black soybean, sesame, onion and garlic. BG was measured during feeding period and serum insulin, lipids and thiobarbituric acid reactive substances(TBARS) and intestinal disaccharidase activities were measured at the end of the three weeks of the feeding. BG increase was lower in the EB enzyme-TR group after 10 days of the experimental diet but lower in EB pill group after 15 days compared with the control group. Serum insulin levels were higher in the EB enzyme-TR and EB pill groups. Intestinal maltase but not sucrase activity was higher in EB enzyme-TR fed group than the control group. Serum levels of total cholesterol and triglyceride were reduced by the EB enzyme-TR and EB pill compared with the control diet. HDL-/total cholesterol was increased by all EB test materials. Serum TBARS levels were lower in the EB ethanol extract and EB pill groups than in the control group and tended to be lower in the other EB groups. It is concluded that the EB enzyme-TR is the best among the EB preparations to be utilized as a functional component for improving blood glucose and lipid profile in diabetic subjects in the future. However, the pill containing low level of the EB powder is also regarded as effective and readily usable when formulated with the several other ingredients of the proper composition.(Supported by the RIC Program of MOCIE, Korea).

Behavioral reaction of hairtail (Trichinus lepturus) to different colors of LED light (LED 색광에 대한 갈치의 행동반응)

  • KIM, Mun-Kwan;AN, Young-Il;PARK, Su-Hyeon;OH, Tae-Cheol;KANG, Hyeong-Cheol;PARK, Yong-Seok
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.52 no.3
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    • pp.183-190
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    • 2016
  • This study carried out an experiment to find out the reaction of hairtail, Trichinus lepturus to the colors of LED light as a basic study on the development of the trolling gear and a method to enable the day-night operation. We used hairtails caught around Seongsan-po, Jeju Island by set nets and hairtail angling. The seven hairtails of the average length 68.9 cm (SD 9.2 cm) and the average weight 135.9 g (SD 47.9 g) were adapted themselves in the experimental water tank, 15 m Self-Governing 1.7 m in height and 1.5 m in depth, and then they were studied. We conducted experiment at the Ocean and Fisheries Research Institute in Jeju Special Self-Governing Province, from November to December 2015, and the sea surface temperature was between 16.5 and $19.5^{\circ}C$. The four colors of LED light, blue, white, green and red, were set up to transmit downward from the marginal area of tank. The 1 meter depth light intensity of LED colors is as follows: $0.09w/m^2/s$ (blue), $0.18w/m^2/s$ (white), $0.04w/m^2/s$ (green) and $0.007w/m^2/s$(red) To know the optimum LED color light, we selected one with better reaction rate after comparison of two colors simultaneously and the selected color was again compared to the other color in a tournament style two times a day (day and night) and ten times totally. The reaction rates were shown as the frequencies of hairtail appearance for 5 minutes in the lighting zone after turning on the LED lights. The reaction rate of the blue was at 97% unlike the red 3% (p < 0.001). The blue was at 75% unlike the green at 25% (p < 0.001). The blue was at 67% unlike the white at 33% (p < 0.001). Therefore, the color of light source showing the highest reaction rate was the blue.

Development and physical properties on the monofilament for gill nets and traps using biodegradable aliphatic polybutylene succinate resin (생분해성 지방족 폴리부틸렌 석시네이트 수지를 이용한 자망과 통발용 단일섬유의 방사기술 개발 및 물리적 특성)

  • Park, Seong-Wook;Bae, Jae-Hyun;Lim, Ji-Hyun;Cha, Bong-Jin;Park, Chang-Doo;Yang, Yong-Su;Ahn, Heui-Chun
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.43 no.4
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    • pp.281-290
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    • 2007
  • This study was aimed not only to develop the gill net and trap made of biodegradable monofilaments in order to prevent a ghost fishing and to protect marine ecosystem, but also to analyze their spinning process and physical properties. Results showed that the spinning speed of biodegradable polybutylene succinate(PBS) monofilament was estimated to be approximately 100m/min when spinning temperature and cooling water temperature were adjusted at $180^{\circ}C$ and $3^{\circ}C$, respectively. The breaking loads of PBS monofilaments were estimated to be $35.3kg/mm^2$ at ${\phi}0.2mm$, $46.5kg/mm^2$ at ${\phi}0.3mm$, and $49.7kg/mm^2$ at ${\phi}0.4mm$ in the dry condition, respectively. However, its breaking loads in the wet condition were reduced by 2.4-5.5%, compared to those in the dry condition. The knotted strength of PBS monofilament at ${\phi}0.2mm$ was estimated to be 98.6% of PE in the dry condition. The breaking load of PBS monofilament at ${\phi}0.3mm$ was evaluated to be 81.8% of PA, and its softness showed 3 times less than that of PA in the wet condition. The breaking load of PBS monofilament at ${\phi}0.4mm$ was 95.3% of PA, and its softness showed 1.6 times less than that of PA in the wet state. However, the load elastic elongations of two kinds of monofilaments were estimated to be 1% higher than that of PA.

Current Status of Registered Korean Patents Related to the Health Functional Food for Skin Care (피부미용 관련 건강기능식품 국내 특허 등록현황)

  • Chung, Kap-Taeck;Lee, Sang-Hyun
    • The Korean Journal of Food And Nutrition
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    • v.25 no.2
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    • pp.308-316
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    • 2012
  • Proper skin care promotes good metabolism and the biological activity of skin, helps maintain the skin in a healthy and beautiful state when combined with nutritional nourishment. Health functional foods are being used for the purpose of enhancing efficient skin care. Health functional foods related to skin care maintain the epidermis, dermal fibroblast layer and subcutaneous tissue that form the skin. Efficient functional foods alleviate the signs of endogenous aging that come with getting older and exogenous aging caused by sunlight. Even though the field of skin care related to health functional foods has received less attention and been the subject of less research compared to functional cosmetics which are developing widely, this area of skin care that maintains and improves the layer of dermal fibroblast through the intake of food, is expected to progress with the commercialization of products in many fields when the related technical research development is galvanized and the related patents are applied for. Research into health functional foods related to skin care in Korea started rather late in comparison to other advanced countries where patents for relevant techniques have been applied for since 1990's together with research conducted on how they might be used for practical purposes. This study used the key words 'skin care, health functional food' to search for Korean patents that have been applied for at the Korean Intellectual Property Office from 1983 to 2011 using the KIPRIS database, in order to help researchers in the related fields by organizing the patented formulas for health functional foods for skin care which have gained attention recently. According to the number of registrations in each industry field, the total number of patents was 1,120 we screened the major patents among them, the field with the largest number was food foodstuff non-alcoholic beverage and preparation or treatment(A23L) with 135, then natural plant medicine & medical supplies and cosmetics(A61K) with 112, microorganisms or enzymes(C12N) with 63, heterocyclic compounds(C07D) with 44, horticulture or cultivation of sea weeds, forestry(A01G) 16 times, listed from the highest to the lowest number of applications. It has been revealed that food, foodstuff, non-alcoholic beverage and preparation or treatment(A23L) was the industry field where the most patents for health functional foods related to skin care were registered.

Crack and Time Effect on Chloride Diffusion Coefficient in Nuclear Power Plant Concrete with 1 Year Curing Period (1년 양생된 고강도 원전 콘크리트의 염화물 확산에 대한 균열 및 시간효과)

  • Chun, Ju-Hyun;Ryu, Hwa-Sung;Yoon, Yong-Sik;Kwon, Seung-Jun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.6
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    • pp.83-90
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    • 2017
  • Concrete structure for nuclear power plant is mass concrete structure with large wall depth and easily permits cracking in early age due to hydration heat and drying shrinkage. It always needs cooling water so that usually located near to sea shore. The crack on concrete surface permits rapid chloride intrusion and also causes more rapid corrosion in the steel. In the study, the effect of age and crack width on chloride diffusion is evaluated for the concrete for nuclear power plant with 6000 psi strength. For the work, various crack widths with 0.0~1.4 mm are induced and accelerated diffusion test is performed for concrete with 56 days, 180days, and 365 days. With increasing crack width over 1.0mm, diffusion coefficient is enlarged to 2.7~3.1 times and significant reduction of diffusion is evaluated due to age effect. Furthermore, apparent diffusion coefficient and surface chloride content are evaluated for the concrete with various crack width exposed to atmospheric zone with salt spraying at the age of 180 days. The results are also analyzed with those from accelerated diffusion test.

Alternative Policy and Actual State on Compensation for Fisheries Damage by Oil Pollution (유류 오염에 의한 어업피해 보상 실태와 대응 방안)

  • Jang, Duck-Jong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.11 no.1 s.22
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    • pp.61-70
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    • 2005
  • The most likely influenced by the oil pollution at the sea is the fisheries industry, because if the destruction if the marine ecological system The rate if compensation for damage from IOPC Fund due to the incident if oil pollution is more or less $20\%$, which is remarkably lower than those cf our adjacent nations or European nations. The reason such a low rate cf compensation is that it is not easy to take evidences if changed caused by oil pollution requested by IOPC Fund due to the environments if our fisheries. Therefore unless the environments if our fisheries is changed completely, it is very difficult to get actual compensation for damages under the existing system, considering the results if the oil pollution damage compensation claim cases up to now. In this study tried to identify the actual benefits of 03FC convention that raises the upper limit if the compensation while keeping the criterion for compensation And proposed to supplement the compensation system of damage caused by oil pollution with analyzing the actual status if compensation from. IOPC Fund for the our oil pollution incidents and the judgment if Supreme Court on the case if oil. pollution acident in Keumdong No.5.

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A Study on the Development of Mobile Robot for Inspection of Hull Surface (선체 외부 검사용 모바일 로봇 개발에 관한 연구)

  • Kim, Jin-Man;Kim, Heon-Hui;Nam, Taek-Kun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.21 no.6
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    • pp.744-750
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    • 2015
  • In this paper, development of mobile robot for the inspection of hull surface was mentioned. In the sea, it is difficult to proceed with the visual inspection of hull side and thus mobile robot for checking the status could be run with strap-on its surface. To do this, permanent magnet module to generate magnetic force between hull surface and mobile robot, and structure to minimize variance of the force under curvature circumstance were considered on the design. Based on the design, mobile robot with four NdFeB, four driving wheels and image aquisition module was applied. Load experiment to check the adhesive force, slip test during stop state and driving test to measure driving speed were executed. From the experiments 13 Kgf adhesive force was obtained and slip was not happened until 8 Kgf load on the inclined plate. Driving speed of mobile robot was measured at 0.82 m/s corresponding to 6.5 ampere. We confirmed the effectiveness of developed mobile robot by experiments to check its characteristics.