• Title/Summary/Keyword: 삼각형의 높이

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Numerical Simulation of Liquid Sloshing in Three- Dimensional Tanks (3차원(次元) 탱크내에서의 액체(液體) 슬로싱의 수치(數値) 해석(解析))

  • J.H. Hwang;I.S. Kim;Y.S. Seol;S.C. Lee;Y.K. Chon
    • Journal of the Society of Naval Architects of Korea
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    • v.28 no.1
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    • pp.12-18
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    • 1991
  • Three-dimensional nonlinear sloshing effects due to tank motions are simulated by solving boundary value problem using the panel method based on boundary integral technique. While Shinkai used boundary elements on which source strengths vary linearly between nodes, the source of constant strength is distributed on each triangular panel in the present study. The source strength at each time step is determined by solving the Fredholm integral equation of the second kind obtained from Green's theorem. To avoid cumulative numerical errors as time elapses, Adam-Bashforth-Moulton method is employed. Numerical examples for the case of partially filled spherical tank on board oscillating in harmonic sway mode or pitch mode are solved. The elevation of the free surface is compared with the result by Shinkai and confirmed in good agreement during early time. The input and the output energy are comparatively evaluated to check the overall accuracy of the present numerical scheme. Although some leakage of energy are found as time marches, it is plausible when we take into account nonlinearities of the problem and the number of panels of the model.

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A Stability Analysis of Geosynthetics Reinforced Soil Slopes II - Evaluation of Required Reinforcement Tensile Force - (토목섬유 보강 성토사면의 안정해석 II. - 소요 보강재 인장력 평가 -)

  • Kim Kyeong-Mo;Kim Hong-Taek;Lee Eun-Soo;Kim Young-Yoon;Ahn Kwang-Kuk
    • Journal of the Korean Geotechnical Society
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    • v.21 no.8
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    • pp.107-116
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    • 2005
  • Generally, when the stability of the geosynthetic reinforced soil slopes is analyzed, the required tensile forces of each reinforcement layers are calculated from total reinforcement forces which are necessary to retain the equilibrium state of slip mass in which the slip surfaces are assumed to be a linear or bilinear. It is assumed that the reinforcement forces are increased or constant with depth. However, according to the instrumented field data and laboratory model test results, the maximum tensile strain of reinforcement in a reinforced soil slope is developed in a certain elevation, not a bottom of the slope. In the concept of reinforced soil, postulated failure surfaces are the traces of the position in which the reinforcement tensile forces are maximum in the layer, and the reinforcement tensile forces are related to the stress state on the postulated failure surface. Therefore, in this study, based on the distribution of normal stress on the slip surface, a new method for the evaluation of required tensile forces is suggested and a number of the instrumented field data are analyzed by newly suggested method. As a result, it is shown that the newly suggested method produces relatively accurate reinforcement tension forces.

Effects of Horseshoe Expander (Horseshoe Expander의 확장 효과에 관한 연구)

  • Chung, Kyu-Rhim;Park, Young-Guk;Lee, Young-Jun;Kim, Hong-Suk
    • The korean journal of orthodontics
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    • v.30 no.5 s.82
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    • pp.553-563
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    • 2000
  • Horseshoe Expander is one of Slow Maxillary Expansion(SME) which aims to accommodate the contra- lateral expansion and midpalatal suture expansion or the palate. The appliance consists of skeleton type strew embedded in split Horseshoe appliance. It is the objectives of the presentation to manifest the changes in dental & craniofacial components subsequent to the application of Horseshoe Expander. The subjects for this study consisted of 32 patients (mean age : 12.7). frontal, lateral cephalometric headfilm were taken and study casts were fabricated before and after expansion. 24 items were measured, compared preexpansion with postexpansion. Especially, palatal volume was measured by means of 'Hydro-measurement method'. Tooth axis measurement on the dental casts were made with Universal bevel protractor, and Horseshoe Expander group were compared with RME group. This study of changes to maxillary expansion with Horseshoe Expander revealed the following significant results. 1. Triangular-shaped expansion pattern appeared in frontal cephalometric headfilm. 2. Palatal plane, occlusal plane, mandibular plane and upper incisor to FH increased in lateral cephalometrir headfilm. 3. Palatal volume increased significantly. A slight bite opening, reduction of occlusal contact points showed in dental casts. 4. A 2.2:1 ratio of the amount of intermolar width in maxilla(orthodontic movement) to maxillary width (orthopedic movement) was determined. 5. Horseshoe Expander group has less buccal tipping tendency than RME group, by taking high correlation coefficients in the upper second premolar and first molar. It was suggested that Horseshoe Expander showed less orthodontic changes, less buccal tipping tendency. In addition, it was effective in maxillary expansion.

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A Study for Seepage Control of Levee with a Pervious Toe Drain (제내 비탈끝 배수공을 이용한 제방의 침투조절에 관한 연구)

  • Kong, Young-San;Kang, Tae-Uk;Lee, Sang-Ho
    • Journal of Korea Water Resources Association
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    • v.45 no.6
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    • pp.569-581
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    • 2012
  • The levee is the facility which is constructed along with river for the protection of landside and for passage of water when there is a flood. When the seepage is exposed to the atmosphere on the landside surface of levee, it may eventually lead to levee failure. The seepage water may be removed from the landside surface by a properly designed drainage system. The purpose of the study is to show seepage control effect of a pervious toe drain, and to compare two drainage methods of a pervious toe drain. One is the pervious toe drain suggested by U.S. Army Corps of Engineers (USACE) and the other is that suggested by Japan Institute of Construction Engineering (JICE). The levee model constructed has the following dimension: the base width is 2.6 m; the crest width is 0.4 m; the side slope 1 : 2. The water depth in the riverside is 0.5 m. The shape of the toe drain by USACE is triangular. The shape of the toe drain by JICE is rectangular. They were installed with the base length of 0.4 m. The levee model without the toe drain showed saturation surface on the land side in the experiment but not with the toe drain. The experiment results was applied to a numerical analysis model using SEEP/W to calibrate and verify. The numerical analysis results for 35 cm and 30 cm drain width showed that the drain by JICE is a little bit safer than the drain by USACE. It is also easier to construct the toe drain by JICE. The results in the study would be applied to plan the seepage control for a levee with pervious toe drain.

Achievement of Excavation of Gwiam(Turtle Rock) and Nakseojae Restoration in Bogil-do Yun,Seondo Wonlim (보길도 윤선도원림(명승 제34호) 낙서재지역 원형복원과 귀암(龜巖) 발굴의 성과)

  • Lee, Won-Ho
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.30 no.3
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    • pp.111-120
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    • 2012
  • This study regards a series of achievement on Wonlim(Garden) Cultural Properties Excavation Project, led by field of landscape architecture. It will mainly describe excavation results of Gwiam(龜巖: Turtle rock) and historical value of it in terms of Nakseojae(樂書齋) restoration in Bogil-do Yun,Seondo Wonlim(Scenic Sites, No.34). Gwiam(Turtle rock) was found 14.6m apart from the north of Nakseojae, and it covered with 10~15m topsoil tilted toward Nakseojae, The size of Gwiam, which was Granite, was 360cm length, 270cm width, 95cm high. The Edge of Gwiam's North west part was of triangular shape forming Turtle head. The back of the Turtle head was form of Tortoise-shell because of wide backboard with both side groove. The southeast part of Gwiam projected was Turtle's tail. This Granite was obvious Turtle shape artificially made, and there are less likely to relocate from place to place. This Turtle-shaped Gwiam is important landmark for Nakseojae, which is one of the four spiritual creatures written in Bogildoji(甫吉島識) and Gosanyugo(孤山遺稿) by Yunwi. According to Bogildoji, it is estimated that Gwiam were on the axis with Soeunbyung(小隱屛), Nakseojae and was buried when Yiguan(Gosan's grandson) reconstructed a building. Also, it was place for enjoying the moon. But, Even after three times excavation in Nakseojae, there was no way to identify further information regarding Gwiam, so it was a matter of mystification. As a result of this study, Gwiam is laid bare to light in at least 260 years, so it is good example for boosting importance of landscape architecture field and restoring Nakseojae. Furthermore, firm base-soil was discovered in 135m high Rock Mass below, so natural ground of Nakseojae can be estimated by this basis. To be conclusion, Preservation Process for Gwiam and Estimation Space through interpretation of four spiritual creatures(四靈) in Gosan's Poetry should be continue.

Assessment of the Position of the Mandibular Foramen and Mandibular Lingula in Children and Adolescents using CBCT (소아 청소년에서 하악공 및 하악소설의 위치에 대한 CBCT 분석)

  • Lee, Jihye;Choi, Namki;Kim, Byunggee;Kim, Seonmi
    • Journal of the korean academy of Pediatric Dentistry
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    • v.48 no.1
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    • pp.64-76
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    • 2021
  • The purpose of this study is to evaluate the position of the mandibular foramen and location and morphological characteristics of the mandibular lingula using Cone-Beam Computed Tomography (CBCT). Mandibular CBCT images of children aged 6 - 16 years were collected. A total of 180 patients were divided into 3 groups, 6 - 7, 10 - 11 and 15 - 16 years, with 30 male and female patients per group. Either side of the ramus was analyzed. The shortest distances from the anterior, posterior, superior and inferior border of the ramus to the mandibular lingula were measured. The shortest distance between the mandibular lingula and the mandibular foramen was also measured. The vertical distance from the mandibular lingula and the mandibular foramen to the occlusal plane was measured. The shapes of the mandibular lingula was classified into 4 types according to the criteria. The distances of the mandibular lingula from the anteroposterior and vertical reference points of the ramus increased in all directions with age. The distance between the mandibular lingula and the mandibular foramen also increased with age. The location of the mandibular lingula and the mandibular foramen in relation to the occlusal plane moved upwards with age. The most common shape of the mandibular lingula was triangular, followed by nodular, truncated and assimilated, and there was no difference in the shape according to age. It is recommended that the horizontal insertion point of the anesthesia from the anterior border of the ramus increased to 17 mm, 18 mm, and 19 mm according to the age groups. It is also suggested that the vertical insertion point increased by 2 - 3 mm, 5 - 6 mm and 9 - 10 mm above the occlusal plane according to the age groups.

Dispersion of Standing Stones at Noseongsan(Mt.Noseong) and Aspect of the Stone Decorated Garden(Soo-suk Jeongwon) at Chongsuk-Sa(Chongsuk Buddhist Temple) in Nonsan City (논산 노성산(魯城山)의 입석(立石) 분포와 총석사(叢石寺) 수석(樹石)의 정원적 면모)

  • Rho, Jae Hyun;Huh, Joon;Jang, Il Young
    • Korean Journal of Heritage: History & Science
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    • v.43 no.1
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    • pp.160-189
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    • 2010
  • This study has been designed to grasp the present situation, shapes and meaning of the standing stones and rock pillars in the whole area of Noseong Mountain Fortress in Nonsan City which have never been academically reported yet. Accordingly, the research was carried out to grasp the spatial identity of Noseong Mt. and Noseong Mountain Fortress and the dispersion of standing stones scattered around inside and outside Noseong Mountain Fortress, while the shapes and structural characteristics of stones were investigated and analyzed focusing on Chongsuk Temple, which was considered to have the highest density of standing stones and greatest values for preservation as a cultural property. In consideration of the reference to the 'Top Sa' (tower temple) at the 'Bul Woo Jo' (Article about Buddhism Houses) of 'Shinjoong Dongguk Yeoji Seungram', theoretical existence of the temple according to surveying investigation, and the excavation records of roof tile pieces with the name of 'Gwan Eum Temple', it is presumed that there had been a Buddhist sanctum inside the fortress and it could be connected to the carved letters, 'Chongsuk Temple'. According the observation survey, the 6th place of standing stones among many other places inside the fortress shows that Chongsuk Temple appears to have the strong characteristics of artificially constructed space in consideration of the size of trees and stones, the composite trend of tree and stone composition, and trace of the adjacent well and strand and the construction of stairway leading to the stone gate. Along with the constellation of the Big Dipper carved on a rock at the same space, the stones, on which the letters of 'Shinseonam', 'Chilseongam' and 'Daejangam' were carved, including 'Chongsuksa', and the carved statue of Buddha, which was assumed to be Avalokitesvara Guan Yin, have offered clue which make it possible to infer that the space was a space for Chilseong and Mountain god(Folk Belief) that had originated from the combination of Buddhism, Taoism and folk religion. According to the actual measurement of standing stones at Chonsuk Temple, it was identified that there were big differences in height among 24 stones in total, ranging from 402~29cm and the averaged distance between each stone appeared to be 23.6cm. And the shape of stones appeared to be standing or flat, and various stones such as mountain-like stones and Buddha-like stones were placed in a special arrangement or assorted arrangement, but the direction of the stones had a consistency pointing to the west. And comparing to the trace of construction of ZEN Landscape Garden well known in the country, the three flat stones except for the standing and shaped stones appeared to have the shape of meditation statue, which is the typical formational factors of a ZEN Landscape Garden, on the basis of formational technique of stones. Among them, the flat stone facing the Buddhist saint statue, was formed by way of symbolization of three-mountain stone, which was assumed to be an offering stone for sacrificial food rather than carrying out ZEN Meditation. In consideration of the formation of standing stones at Chong-suk Temple, which was carried out in the composite stoning method based using the scalene triangle with ratio of 3:5:7 in order to seek the in-depth beauty based on the stone statues of three Buddhas where the three factors such as heaven, earth and humans are embodied in the elevated or flat formation, the stones at Chongsuk Temple and the space seemed to the trace of contracted garden construction that was formed with stones for a temple, so that could be used for ZEN meditation.