• Title, Summary, Keyword: Hull from development

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Development of hull form of small and medium size coastal ships (연안항로용 중소형 섭박의 선형 개발)

  • 조용진;고창두;김성환
    • Journal of Ocean Engineering and Technology
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    • v.11 no.2
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    • pp.131-137
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    • 1997
  • The technology of small and medium sized shipbuilding companies is lower relatively to major shipbuilding companies, and should be up-graded from the viewpoint of national economic development. In spite that hul form design is one of the most important elements with respect to shipbuilding technology, small and medium sized shipbuilding companies are incapable of developing hull form. Inorder to support technically such companies hull form development was carried out for G/T 999ton class tanker and D/W 4990ton class tanker which are the typical vessels operating in coastal area. The operating efficiency for the developed hull forms are impeoved by 30% for G/T 999ton class tanker and 24% for D/W 4990 tonclass tanker respectively. The results of hull form development including ship model test and performance analysis are presented in this paper.

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Antioxidative Constituents and Activities of Acorn hull and Chestnut Hull (도토리와 밤 외피의 항산화 성분 및 활성)

  • 차배천;이혜원;임태진
    • YAKHAK HOEJI
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    • v.47 no.4
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    • pp.212-217
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    • 2003
  • We have carried out the antioxidative activity of nuts species for the development of antioxidant from natural products. From our previous report, EtOAc and n-BuOH extracts of acorn hull and chestnut hull were found to have a strong antioxidative activity in various antioxidant experiment. In the continuous study, we isolated several compounds from EtOAc and n-BuOH extracts of acorn hull and chestnut hull by fractionation using column chromatography. The structures of isolated compounds were identified as catechin, naringenin and ellagic acid on the basis of their spectroscopic properties and by comparison of their physical and spectra data with published value. Antioxidative activities of catechin, naringenin and ellagic acid were measured by DPPH, ferric-thiocyanate and Rancimat method.

Antioxidant Compounds and Antioxidant Activities of the Methanolic Extracts from Milling Fractions of Sorghum (Sorghum bicolor L. Moench) (수수 도정부위별 메탄올 추출물의 항산화성분 및 항산화활성)

  • Woo, Koan-Sik;Seo, Myung-Chul;Kang, Jong-Rae;Ko, Jee-Yeon;Song, Seuk-Bo;Lee, Jae-Saeng;Oh, Byeong-Geun;Park, Gi-Do;Lee, Yong-Hwan;Nam, Min-Hee;Jeong, Heon-Sang
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.39 no.11
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    • pp.1695-1699
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    • 2010
  • The purpose of this study was to evaluate the antioxidant compounds and their activities of the methanolic extracts from milling fractions of sorghum. To determine the antioxidant compounds in the methanolic extract from the milling fractions, the content of polyphenol, flavonoids, tannin, anthocyanins and proanthocyanidin were measured by spectrophotometric methods. These were evaluated for antioxidative activities by ABTS and DPPH radical scavenging assays. The extraction yield of hull, bran and grain of sorghum were 9.95, 19.05 and 2.94%, respectively. The methanolic extracts from sorghum bran showed generally higher antioxidant activities than the extracts from hull and grain of sorghum. In addition, antioxidant compounds distributed much higher contents in sorghum bran extract than in the extracts from hull and grain of sorghum. A significant correlation was also noted between free radical scavenging activity and polyphenolic compounds. The results of this study show that notable antioxidant activity in sorghum bran is considered to have significant health benefits.

A Study on the Resistance Reduction of G/T 190ton Class Main Vessel in Korean Large Purse Seiner Fishing System (G/T 190톤급 한국 대형선망 본선의 저항저감에 대한 연구)

  • Park, Ae-Seon;Lee, Young-Gill;Kim, Doo-Dong;Yu, Jin-Won;Ha, Yoon-Jin;Jin, Song-Han
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.5
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    • pp.367-375
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    • 2012
  • In this study, hull form of main vessel of Korean large purse seiner fishing industry is developed for the improvement of resistance performance as well as for the satisfaction to the Standard of Fishing Convention, ILO. Through the modification of reference hull form parameters and local characteristics, the hull form development is carried out. The optimum hull form parameters are searched by Sequential Quadratic Programing(SQP) method with the power estimation method of Holtrop & Mannen. To minimize the wave resistance, bulbous bow parameters are determined by the bulbous bow design method of Alvarino. The plasmatic curve is redesigned from that of the reference hull by using Lackenby method. The resistance performances of the reference and designed hull forms are estimated by using numerical simulation method. Also, the judgment of seakeeping ability and the estimation of intact stability for the designed hull form is carried out. As a result, the optimum hull form is proposed. To verify the improvement of resistance performance, model tests are carried out in towing tank. The results show that the resistance of the designed hull form is about 14% smaller than that of the reference hull from at design speed. A new hull form proposed in this study can contribute to the development of the main vessel hull form of Korean large purse seiner fishing system.

Study of Hull Form Development of 5-Ton-Class Catamaran-Type Coastal Fishing Boat for Welfare Accommodation of Fishing Crew (어선원 복지공간 확보를 위한 5톤급 쌍동형 연안어선 선형개발에 관한 연구)

  • Jeong, Uh-Cheul;Kim, Hyun-Soo;Kwon, Soo-Yeon;Choi, Ji-Hoon
    • Journal of Ocean Engineering and Technology
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    • v.29 no.6
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    • pp.405-410
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    • 2015
  • This paper reports the hull form development and resistance performance of a 5-ton-class catamaran-type coastal fishing boat. The weight estimation and preliminary design were basically extracted from existing coastal fishing vessels. In addition, the resistance performance was investigated using a model test in a high-speed circulating water channel and was analyzed in comparison to an existing catamaran fishing vessel. As a result, the modified hull achieved an approximately 30% reduction in resistance compared to the previous hull. The stability or boarding sensitivity of the modified hull form was more stable or comfortable than the original hull form based on a trim and sinkage comparison between the two boats.

A Study on the Development of Activated Carbon from Rice-Hull (왕겨를 이용한 활성탄 개발에 관한 연구 (I))

  • 이희자;조양석;조광명
    • Journal of Environmental Science International
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    • v.9 no.1
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    • pp.81-88
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    • 2000
  • Every year, 1.1 million tons of rice-hull are produced in South Korea by the by-product in pounding rice. But they has mainly been utilized as a fuel, agricultural compost and moisture proofs. So, it's very valuable to use waste rice-hull for activated carbon manufacture. SiO2 content was the highest among inorganics in rice-hull. Therefore, the SiO2 extraction experiments were carried out under the various conditions of pH 9 to 14, reaction time from 2 to 24 hrs and various temperature of 20 to 100℃. The results showed that increase in pH and temperature enhanced SiO2 extraction from the carbonized rice-hull. The surface area of the carbonized rice-hull indicating activated carbon adsorption capacity was very small as 178∼191 m2/g at first. However, it was increased to 610∼675 m2/g when extracted in alkali solution at 100℃. When the mixing rate of carbonized rice-hull and NaOH was 1:1.5, iodine No. and surface area of activated rice-hull during 10 min at 700℃ were 1,650 mg/g and 1837 m2/g, respectively. Subsequently, an activated carbon with specific surface area of 1,300∼1,900m2/g was manufactured in a short contact time of 10∼30 min with a mixing rate of 1:1.5 in carbonized rice-hull and NaOH, and iodine No. and specific surface area increased as the amount of SiO2 removal increased.

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A study on the development of resistance and pitching improving device for high speed fishing vessel (고속어선의 저항 및 핏칭 개선장치 개발에 관한 연구)

  • 이귀주;오훈택
    • Journal of Ocean Engineering and Technology
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    • v.11 no.3
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    • pp.89-94
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    • 1997
  • In the design of high speed fishing vessel, its hull form has to be decided from a view point of resistance and propulsion performance without negelction of seakeeping characteristics. In spite of many efforts, the performance improvement by hull form itself has its limitations, specially for high speed craft. In this paper, the development of performance of resistance and seakeeping improving appendage for high speed planing hull on behalft of the hull form of fishing vessel has been introduced. The developed appendage verified its effectiveness in the full scale test.

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A Study on the Hull Form Design of High-Speed Trimaran (고속 삼동선형 설계에 관한 연구)

  • 이영길;최동섭;김규석
    • Journal of the Society of Naval Architects of Korea
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    • v.41 no.3
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    • pp.60-71
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    • 2004
  • Nowadays, We have had a growing interest in high-speed vessels' because it is very important to save time and cost in marine transportation. The development of hull form for high-speed vessels is high priority to secure the competitive power for the transportation of cargos. Therefore, the demand of the high-speed vessels is gradually increased, but the conventional hull forms are limited by rapidly increasing resistance upon the increase of ship speed in high-speed region. Therefore, new concepts for the hull form of high-speed vessels have been requested. One of the derived hull forms for that demand is the hull form of trimaran type. Trimaran has a very slender main hull as compared with conventional single hull so that is reduced in wave resistance. The slender main hull has the undesirable characteristics of stability, but two side hulls make up for the week points in the stability. That is, trimaran is able to have desirable performances for the resistance and stability. In this paper, for the design of 200TEU class container vessel with trimaran type, which will be cruised in Yellow-Sea region, firstly a preliminary hull is designed, and the model test is carried out with the variation of side hull position. From the experience of the preliminary hull form design, an improved hull form for the 200TEU container are designed, and the model tests are carried out. Also, a numerical computation technique is adopted for the simulation of flow phenomena around the designed hull forms. The final hull form is compared with existing ships for the resistance performance from the computation with computer and ship model tests.

A Study on Improvement in the Resistance Performance of Planing hulls by Hull Shape Optimization (고속활주선의 선형 최적화를 통한 저항성능 개선에 관한 연구)

  • Kim, Sunbum
    • Journal of the Korea Society for Simulation
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    • v.27 no.2
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    • pp.83-90
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    • 2018
  • This paper describes the method of hull shape optimization to improve the resistance performance of planing hulls when a reference hull shape and its principal dimensions are given. First, the planing hull of precedent research is adopted as the reference hull and an optimization problem is formulated by defining hull shape parameters. The search space of this research is discretized for computing cost and DPSO(Discrete binary version of Particle Swarm Optimization) method is used to solve the optimization problem. As the result of optimization, the decrease of resistance is confirmed from the comparison between the reference hull's and the modified hull's planing performance from computational results.

A Study on the Bow Wave Characteristics for the Resistance-Minimized Hull Form of Small Fishing Boat (저항최소화 소형 어선선형의 선수파 특성에 관한 연구)

  • Yu, Jin-Won;Lee, Young-Gill
    • Journal of the Society of Naval Architects of Korea
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    • v.45 no.2
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    • pp.124-131
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    • 2008
  • This paper presents the analysis of resistance performance and bow waves for the resistance-minimized hull form of small fishing boat by using numerical simulations and model tests. The resistance-minimized hull form is developed from an original hull form which is selected from existing small fisher boats in our country. In order to estimate the resistance performance for the original and the developed hull form, several numerical simulations and model tests are carried out. Marker and Cell(MAC) method and Marker-Density method are adopted to simulate the free-surface bow waves around advancing hull surface. The results of numerical simulations are compared with the model tests in towing tank. The results show that the resistance performance of the resistance-minimized hull form is improved than that of the original hull form. The results of this study will be a good guide to the hull form development of small fishing boats in future.