• Journal of Mechanical Science and Technology
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• 제17권6호
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• pp.879-887
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• 2003

The flow in a parallel walled test channel, when obstructed with a geometry at the entrance, can be forward, reverse and stagnant depending on the position of the obstruction. This interesting flow phenomenon has potential benefit in the control of energy and various flows in the process industry In this experiment, the flat plate obstruction geometry was used as an obstruction at the entry of the test channel. The parameters that influence the flow inside and around the test channel were the gap (g) between the test channel and the obstruction geometry, the length (L) of the test channel and the Reynolds number (Re). The effect of the gap to channel width ratio (g/w) on the magnitude of the velocity ratio (V$\_$i/ / V$\_$o/ : velocity inside/ velocity outside the test channel) was investigated for a range of Reynolds numbers. The maximum reverse flow observed was nearly 20% to 60% of the outside velocity for Reynolds number ranging from 1000 to 9000 at g/w ratio of 1.5. The maximum forward velocity inside the test channel was found 80% of the outside velocity at higher g/w ratio of 8. The effect of the test channel length on the velocity ratio was investigated for different g/w ratios and a fixed Reynolds number of 4000. The influence of the Reynolds number on the velocity ratio is also discussed and presented for different gap to width ratio (g/w). The flow visualisation photographs showing fluid motion inside and around the test channel are also presented and discussed.

• 한국항해항만학회지
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• 제28권7호
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• pp.641-645
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• 2004

In this study, we focus on the submerged plate built into the Very Large Floating Structure with the partial openings of 5m long, which enables the reverse flow of incident wave to generate the wave breaking. The purpose of this study is to investigate the characteristics of wave exciting forces acting on the submerged plate. Firstly, we have carried out the extensive experiments to understand the characteristics of the wave exciting forces. Then we have performed the numerical simulations by applying the Marker and Cell method and compared with the experimental results. We discuss the validity of MAC method and the effects of the submerged plate on the motion of VLFS.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1994년도 추계학술대회
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• pp.75-78
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• 1994

Clinically, proximal bone resorption in the femur is frequently seen postoperatively on the follow up X-rays after total hip replacement(THR). We developed the finite element model of cementless THR. The model is two dimensional side plate model, whereby the three dimensional structural integrity of the bone can be accounted for by a separate two dimensional mesh, a side plate. The subject of this article is the development and application of this two dimensional side plate FEM to study the reverse effect of the various degree of bone resorption of femur after THR. The results of this study indicates that two dimensional side plate model is good and simple alternative to complex three dimensional model and the severity of the proximal bone resorption has the effect of more increasing stress on the cortex at the level of femoral stem tip.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 춘계학술대회 논문집
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• pp.203-207
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• 2004

In this study, we focus on the submerged plate built into the Very Large Floating Structure with the partial openings of 5m long, which enables the reverse flow of incident wave to generate the wave breaking. The purpose of this study is to investigate the characteristics of wave exciting forces acting on the submerged plate. Firstly, we have carried out the extensive experiments to understand the characteristics of the wave exciting forces. Then we have performed the numerical simulations by applying the Marker and Cell method and compare with the experimental results. We discuss the validity of MAC method and the effects of the submerged plate on the motion of VLFS.

• 대한의용생체공학회:의공학회지
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• 제16권1호
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• pp.25-32
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• 1995

Clinically, proximal bone resorption in the femur is frequently seen postoperatively on the follow up XI-rays after total hip replacement (THR). We developed the finite element model of cementless THR. The model is two dimensional side plate model, whereby the three dimensional structural integrity of the bone can be accounted for by a separate two dimensional mesh, a side plate. The subject of this article is the development and application of this two dimensional side plate FEM to study the reverse effect of the various degree of bone resorption of femur after THR. The results of this study indicates that 1) two dimensional side plate model is good and simple alternative to complex three dimensional model and 2) the severity of the proximal bone resorption has the effect of more increasing stress on the cortex at the level of femoral stem tip.

• 한국강구조학회 논문집
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• 제24권6호
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• pp.659-670
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• 2012

본 연구에서는 개단면 리브 보강판에 대하여 여러 가지 제원 변화에 따른 국부 처짐과 국부 모멘트를 정형화하고자 하였다. 평강 리브와 역T형 리브를 갖는 여러 가지 보강판을 분석한 결과, 하부 플랜지가 국부 거동에 미치는 영향이 매우 작아 국부 거동은 리브 간격, 복부 두께와 높이, 판 두께에 대한 비율 함수로 표현할 수 있음을 알 수 있었다. 또한, 평강 리브와 역T형 리브를 갖는 보강판의 비율 함수가 유사한 결과를 나타내어 하나의 비율 함수로 통합 가능하였으며, 이를 적용한 결과 타당한 결과를 나타내었다. 다른 형태의 보강판에 비율 함수를 적용한 결과, 오차율 증가가 크지 않아 본 연구의 적용성을 확인할 수 있었다. 따라서 본 연구에서 제안한 국부 거동에 대한 비율 함수식을 이용하면, 개단면 리브를 갖는 보강판의 국부 처짐과 국부 모멘트에 대하여 제원과 상관없이 간편하게 타당한 결과를 얻을 수 있을 것으로 판단된다.

• 한국해양공학회지
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• 제31권6호
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• pp.425-430
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• 2017

In order to reduce the cost of corrections and time needed for the block assembly process, the reverse setting method is applied for a back-heated block to neutralize deck deformation. The proper reverse setting shape for a back-heated block to correct deformation improved the deck flatness, but an excessive amount of reverse setting could inversely affect the flatness of the block. A prediction method was developed for the proper reverse setting shape using a back-heated block, considering the complex geometry of blocks, thickness of the deck plate, and thermal loading conditions such as welding and back-heating. The prediction method was developed by combining the re-meshing technique and inherent strain-based deformation analysis using the finite element method. Because the flatness deviation was decreased until the lower critical point and thereafter it tended to increase again, the optimum value for which the flatness was the best case was selected by repeatedly calculating the predefined reverse setting values. Based on this analysis and the study of the back-heating deformation of large assembly blocks, including the reverse setting shape, the mechanism for selecting the optimum reverse setting value was identified. The developed method was applied to the actual blocks of a ship, and it was confirmed that the flatness of the block was improved. It is concluded that the developed prediction method can be used to predict the optimum reverse setting shape value of a ship's block, which will reduce the cost of corrections in the construction stage.

• 대한기계학회논문집B
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• 제21권9호
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• pp.1105-1114
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• 1997

The heat transfer characteristics of free surface water jet impinging normally against a flat uniform heat flux surface were investigated. This deals with the effect of three nozzle configurations (Cone type, Reverse cone type, Vertical circular type) on the local and the average heat transfer. Heat transfer measurements were made for water jet issuing from a nozzle of which exit diameter 8 mm. The experimental conditions investigated are Reynolds number range of 27000 ~ 70000( $V_{O}$=3 ~ 8 m/s), nozzle-to-target plate distances H/D=2 ~ 10, and radial distance from the stagnation point r/D ~ = 0 ~ 7.42. For all jet velocities of H/D=2, the local Nusselt number decreased monotonically with increasing radial distance. However, for H/D from 4 to 10, and for the jet velocity $V_{O}$.geq.7 m/s for Cone type nozzle and $V_{O}$.geq.6 m/s for the other type nozzles, the Nusselt number distributions exhibited secondary peaks at r/D=3 ~ 3.5. For Reverse cone type nozzle and Vertical circular nozzle, the maximum stagnation point heat transfer and the maximum average heat transfer occurs at H/D=8. But for the Cone type nozzle, the maximum stagnation and average heat transfer occurs at H/D=10, 4, respectively. From the optimum nozzle-to-target plate distance, the stagnation and the average heat transfer reveal the following ranking: Reverse cone type nozzle, Vertical circular type nozzle, Cone type nozzle.ozzle.

• 한국식품위생안전성학회지
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• 제19권4호
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• pp.193-197
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• 2004

산삼배양추출물의 세균에서의 돌연변이 유발성 검색을 위하여 Salmonella typhimurium의 히스티딘 요구성 균주 LA100, TA1535, TA98 및 TA1537의 4개의 균주와 대장균 Escherichia coli의 트립토판 요구성 균주인 WP2 uvrA를 이용해 복귀돌연변이 시험을 실시하였다 시험물질은 멸균생리식염수에 용해하여 처리하였다. 대사활성계 적용 및 미적용시 모든 균주에 대해 0, 62, 185, 556, 1,667 및 5,000{\mu}g/plate의 범위를 설정하고 각각 음성 및 양성대 조군으로 시험군을 구성해 본 시험을 실시하였다. 시험 결과 모든 균주에서 최고농도에 이르기까지 집락수의 일관성 있는 증가는 나타나지 않았다. 이상의 결과를 종합할 때, 시험물질 산삼배양추출물은 본 시험조건 하에 사용한 시험균주들의 복귀돌연변이를 유발하지 않는 것으로 사료된다.

• 대한한의학회지
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• 제29권3호
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• pp.1-10
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• 2008

Objectives: This study was to assess the toxicity of Sipjeondaebo-tang by bacterial reverse mutation test. Methods: In this study, to evaluate the bacterial reverse mutation of Sipjeondaebo-tang water-extract, the in vitro Ames test using Salmonella typhimurium (TA98, TA100, TA1,535, TA1,537) and Escherichia coli(WP2uvrA) were performed with Sipjeondaebo-tang water extract at the concentrations 0, 312, 625, 1250, 2500 and 5000 ${\mu}g/plate$. Results: Sipjeondaebo-tang water extract was negative in Ames test with both Salmonella typhimurium or Escherichia coli with and without rat liver microsomal enzyme (S9- fraction and S+ fraction). Conclusions: According to these results, we concluded that a Sipjeondaebo-tang water extract did not cause bacterial reverse mutation.