• Journal of Ocean Engineering and Technology
• /
• v.23 no.3
• /
• pp.14-19
• /
• 2009

The present study developed a model to estimate the light weight of an ultra-large container ship. The weight estimation model utilized container ship data obtained from shipyards and the subdivided this weight data into appropriate weight groups. Parameters potentially affecting the group weight were selected and expanded based on experience for weight estimation, and a correlation analysis was performed by the SPSS program to determine the key parameters characterizing the group weight. A weight estimation model applying the multi-regression analysis was proposed to assess the weight of an ultra-large container ship at the preliminary design stage, and the results obtained by the suggested method showed good agreement with the shipyard data.

• Journal of the Society of Naval Architects of Korea
• /
• v.48 no.2
• /
• pp.99-106
• /
• 2011

The appearance of CSR changes the concept of the hull form design as well as structural design, since the application of CSR inevitably brings the lightweight increase of a ship. Keeping the original design constraints such as principal particulars, deadweight, and speed performance, designers have to increase the volume of the hull form. As a result, the entrance angle at bow end should become larger, which results in blunter waterline shape. For a slow and full ship having high $C_B$ more than 0.85, a new concept of bow shape has been required to alleviate the increase of wave-making resistance, since it is very difficult to improve waterline and frameline shape for such a full ship. In this paper a new bow shape of Capesize Bulk Carrier was developed to improve its wave-making characteristics without incompliance with the design constraints. For loading manual calculation, NAPA software was used. FLUENT6.3.26 and WAVIS1.4 were used to evaluate resistance performance of the subject hull forms. The newly designed hull form was tested at SSPA model basin for the final confirmation of resistance and propulsion performance of the ship. It was found that the new bow shape of a Capesize Bulk Carrier improved the resistance characteristics greatly compared to a conventional bulbous bow. The other benefits of new bow shape on the manufacturability were also investigated.

• Journal of Korea Ship Safrty Technology Authority
• /
• s.33
• /
• pp.32-52
• /
• 2012

선박의 경사시험에 사용되는 수동식 계측기기는 측정 자체가 사람의 관능에 의존하기 때문에 현장계측자 개인의 경험에 따라 측정 데이타의 신뢰도에 편차가 발생할 개연성이 높다. 그러나 경험치에 의존하지 않고 경사시험의 신뢰성을 담보할 측정방법의 개선이나 개발은 현재까지 없었다. 경사시험 시 정밀한 계측센서를 이용하여 경사각을 계측한다면, 선박의 복원성판정에 정확성을 기할 수 있을 것이다. 따라서 본 연구에서는 전자식 자이로 센서가 내장된 스마트폰(태블릿 PC)을 이용하여 선박의 경사각을 계측하고, 아울러 그에 따른 선박의 경하 상태의 배수량 및 중량중심을 자동으로 계산할 수 있는 앱을 개발하여 선박 복원성판정의 유효성을 검증하였다.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.18 no.2
• /
• pp.94-100
• /
• 1985

M/S Pusan 403(GT 243, 1000ps) was originally built as a research vessel on skipjack pole and line fishing in 1972. She had begun to serve as a fishing training ship of National Fisheries University of Pusan from 1974, since the interior structure has been remodelled and some weight articles have been removed, her stability is in doubt. The authors carried out an inclining experiment by using two pendulums at fore and aft with two weights on both sides. Each value obtained was compared with the IMO safety code for fishing vessels and safety regulation for fishing vessels of Korea. 1. The GZ value, being 0.207 m under light ship condition and 0.325 m under departure condition with full load, can be assumed as no impediment on her stability, 2. Under the light ship condition, GM decreased by 0.046 m and KG increased by 0.141 m, compared with the values determined at the time of official sea trial. Therefore, no impediment on the stability exists. 3. The GM decreased by 0.163 m and the KG increased by 0.173 m, compared with the values determined at the time of official sea trial. In no consideration of the free surface effects of liquid in the oil and fresh water tanks, no impediment on the stability exists. But, in consideration of the free surface effect, it may be regarded that some impediment exists.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.6
• /
• pp.593-599
• /
• 2016

Incheon Bridge is 13.38 km long with an 800 m span, connecting Incheon International Airport and Songdo International City, Per hour 73.8 vessels navigate this space. The purpose of this study was to suggest a safe passing speed based on the displacement of a vessel based on the safety criteria of Incheon Bridge's anti-collision fence, which was designed during its initial construction. As AASHTO LRFD suggested, vessel collision energy, vessel collision velocity, and the hydrodynamic mass coefficient were considered to derive a safe vessel traffic speed. Incheon Bridge's anti-collision fence was designed so that 100,000 DWT vessels can navigate at a speed of 10 knot. This research suggests a safe speed for vessel traffic through a comparative analysis of an experimental ship's (300,000 DWT) speed and cargo conditions, regulation speed has been calculated according to the collision energy under each set of conditions. Additionally, safe traffic vessel's safe speed was analyzed with reference to tidal levels. Results from the experimental ship showed that a vessel of maximum 150,000 DWT is able to pass Incheon Bridge at a maximum of 7 knots with an above average water level, and is able to pass the bridge with a maximum of 8 knots under ballast conditions.

• The Korean Journal of Malacology
• /
• v.24 no.3
• /
• pp.175-188
• /
• 2008

This study was performed to describe the influence of water temperature and salinity on the filtration rate of the hard clam, Meretrix petechialis. The filtration rates of hard clams showed significant differences depending on both water temperature and age group (two-way ANOVA, p < 0.001). The filtration rate of all the hard clams, aged from 1 to 4 years, was generally reduced in low temperature range ( $5-15^{\circ}C$). As the water temperature increased, the filtration rate increased exponentially. The filtration rate was relatively high in $20-30^{\circ}C$ water temperature range, but rapidly decreased again at around $35^{\circ}C$. Variations in the data for filtration rates of hard clams, relative to age and changing water temperature, were used to determine the temperature coefficient $Q_{10}$ in each water temperature range. In $5-15^{\circ}C$ temperature range, every age group showed the highest $Q_{10}$ figure. It was found that on the whole, the higher the water temperature was, the lower the number of $Q_{10}$ was. Regardless of age, the number of $Q_{10}$ was higher in the lower water temperature range. In $25-35^{\circ}C$ temperature range, the number of $Q_{10}$ was less than 1.00 in all age groups, implying that this is the range in which the filtration rate decreased. Variations in the filtration rate also showed very clear differences (two-way ANOVA, p < 0.001) according to changing salinity and age. All the age groups, from 1 to 4 year olds, showed low filtration rates at both low salinity (10-15 psu) and high salinity (40 psu). The highest filtration rate was recorded at 30 psu, and relatively high filtration rates were found around 30 psu. However, the Student-Newman-Keuls post hoc multiple comparison test found that the hard clams in the 1-year group showed high filtration rates in a relatively narrower salinity range compared to those in the 2, 3, and 4 year groups. In other words, hard clams in the 2, 3, and 4 year groups showed high filtration rates at higher levels of salinity.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.11
• /
• pp.1358-1365
• /
• 2017

This study evaluated the quality characteristics of muffins prepared with different amounts (0%, 10%, 20%, 30%, 50%) of fucoidan red yeast (Monascus purpureus) rice powder (FRYR). The weight and pH of muffins increased as the amount of FRYR increased. The height and baking loss rate of muffins significantly decreased when amounts of FRYR increased (P<0.05), whereas moisture content was not significantly different between all samples. L value and b value of muffins significantly decreased when amounts of FRYR increased (P<0.05). However, a value of muffins significantly increased when amounts of FRYR increased (P<0.05). Hardness, chewiness, and brittleness increased with increasing FRYR concentration. Cohesiveness was higher with 30% FRYR, whereas springiness was not significantly different between the samples. In the sensory evaluation, the appearance and crumb color of muffins was higher in groups containing 0% FRYR, whereas flavor, taste, texture, and overall acceptability scores were highest for muffins with 50% FRYR added. The total polyphenol content and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity of muffins significantly increased with increasing addition of FRYR (P<0.05). Therefore, addition of FRYR could satisfy the sensory function and functional requirements of muffins. Furthermore, this study proposes the development of various products using fucoidan red yeast rice.

• Economic and Environmental Geology
• /
• v.55 no.5
• /
• pp.429-438
• /
• 2022

This study evaluated the effect of the degree of weathering on the particle size distribution and the amount of fine particles generated in the aggregate production process during the crushing of igneous rock. Rock samples were collected from three areas with differences in strength from the Schmith hammer measurement at the aggregate quarry in Geochang, Gyeongsangbuk-do. After crushing with a jaw crusher under the same conditions in laboratory, particle size analysis, mineral analysis, chemical analysis, and weathering index were calculated. The Schmidt hammer measurements were 56, 28, and <10, and the CIA and CIW values of weathering index were also different, so the rock samples were classified into hard rock, soft rock, and weathered rock according to the weathering degree. It shows a smaller particle size distribution toward weathered rocks under the microscope, and the proportion of altered clay minerals such as sericite increased. The composition of feldspar and quartz was high for hard rock, and the ratio of muscovite and kaolinite was low. As a result of the crushing of the jaw crusher, hard rock produced a lot of coarse crushed material (13.2mm), while soft rock and weathered rock produced fine crushed material (4.75mm). The former showed the characteristics of the beta distribution curve, and the latter showed the bimodal distribution curve. The production of fine rock particles (based on 0.71mm of sieve, wt. %) increased to 13%<21%<22% in hard rock, soft rock, and weathered rock, and the greater the degree of weathering, the more fine rock particles were generated. The fine particles are recovered by the operation of the sand unit in the wet aggregate production process. Therefore, in order to minimize the amount of sludge generated in the aggregate production process, it was judged that a study on the optimal operation of cyclones could be necessary.