• 한국분무공학회지
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• 제16권2호
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• pp.82-89
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• 2011

When pipe components made of carbon steel in nuclear, fossil, and industry plants are exposed to flowing fluid, wall thinning caused by FAC(flow accelerated corrosion) can be generated and eventually ruptured at the position of pressure boundary. The aim of this study is to identify the locations at which local wall thinning occurs and to determine the turbulence coefficient related to local wall thinning. Experiment and numerical analyses for the tee sections of down scaled piping components were performed and the results were compared. In particular, flow visualization experiment which was used alkali metallic salt was performed to find actual location of local wall thinning inside tee components. In order to determine the relationship between turbulence coefficients and local wall thinning, numerical analyses were performed for tee components in the main feedwater systems. The turbulence coefficients based on the numerical analyses were compared with the local wall thinning based on the measured data. From the comparison of the results, the vertical flow velocity component(Vr) flowing to the wall after separating in the wall due to the geometrical configuration and colliding with the wall directly at an angle of some degree was analogous to the configuration of local wall thinning.

• 건축역사연구
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• 제17권5호
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• pp.7-22
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• 2008

The purpose of this study is to examine the function of wall posts in pit-houses in the Bronze Age, in the Kyung-nam Province. Wall posts were found as post-holes, created after wooden posts had decayed. In this research, the role of wall posts is newly defined from the perspective of a construction engineering. While existing studies in archaeology regard wall posts as sub-posts that support the roof of a pit-house, this study views wall posts as piles installed to support the soil wall, not as sub-posts. Based on the existing reports on excavation in prehistoric settlement sites by archaeologists, the study examines the remnants of the wall posts and remains after a fire. The main findings of this study are threefold. First, the wall posts were installed not as posts but as piles, cut sharply and hammered along the building lines of a pit-house. Second, wall piles were used to support the walls during earthwork, such as excavating and banking for low ground, mostly because a large amount of soil is often lost during the process. Third, wall piles were used as post piles of retaining walls that enabled the installation of transverse wall panels, which were used to prevent the soil loss.

• KIEAE Journal
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• 제7권2호
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• pp.3-8
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• 2007

Recently, the structural system of public residential buildings has been changed from the reinforced concrete (RC) wall system to the (PC) wall and moment resisting systems. Thus, it is important to develop the suitable wall system in accordance with the trend of the modern structural system. This paper presents the basic study on the suitable boundary wall in high-rise buildings. The research also demonstrates the evaluation results on sound characteristics in the aspect of sound insulation. The evaluation of sound insulation capability for the commercialized wall structure was conducted based on literature survey while the measurement of sound insulation capability for the light-weght EPP concrete was performed in according to KS F2808 in laboratory. The main objective of this research is to propose the most suitable dry wall system as a sound insulation structure through the comparison and analysis of frequency characteristics and weight-acoustic attenuation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.727-732
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• 2000

Four 1/2-scale wall specimens with flange are tested. The purpose of this study is to investigate experimentally structural behavior of flanged walls in wall slab system apartment buildings considering effective width of flange wall. Main variables are the length of web wall and concrete strength. Cyclic lateral loads are applied at the top of the walls. A constant axial load of approximately $0.1f_{ck}\cdotA_g$ is maintained during the testing. Test result shows that the capacity of the wall was governed by aspect ratios rather than concrete strengths and that initial stiffness and strength of specimens is increased with increasing the stiffness of web wall.

• 대한기계학회논문집
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• 제18권6호
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• pp.1582-1589
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• 1994

The characteristics Prandt1-Meyer expansion of supersonic flow with condensation through a wavy wall in a channel are investigated by experiment and numerical direct marching method of characteristics. In the present study, for the case of moist air flow in the type of indraft supersonic wind tunnel, the dependency of location of formation and reflection of the oblique shock wave generated by the wavy wall and the distribution of flow properties, on the specific humidity and temperature at the entrance of wavy wall and the attack angle of the wavy wall to the main stream is clarified by schlieren photograph, distribution of static pressure and Mach number, and plots of numerical results. Also, we confirm that the wavy wall plays an important key role in the formation of oblique shock wave, and that the effect of condensation on the flow field appears apparently.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.215-216
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• 2019

The following conclusions were reached through the research on the development of the required performance extraction tools for the application and utilization of various construction methods of lightweght dry wall. 1) Performance required for walls of apartment buildings can be divided into safety, habitation, durability and productivity. Among these, horizontal load resistance, shock resistance, anti-seismic performance, insulation, and acoustic characteristics are the main performance that correspond to dry walls. In addition, safety related to toxic gases and contaminants are required according to recent eco-friendly requirements. 2) To select a wall according to the required performance of an inner wall applied to an apartment, a map tool in the form of 2D matrices was constructed to enable the required performance to be applied, indicating that the wall location and wall material and its differentiating according to the old method.

• Journal of Yeungnam Medical Science
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• 제34권2호
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• pp.279-284
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• 2017

Pulmonary artery sarcoma (PAS) is a rare and fatal disease that often mimics chronic thromboembolic pulmonary hypertension (CTEPH); therefore, diagnosis of PAS is often delayed. Herein, a healthy 74-year-old man was presented with a 4-month history of dyspnea. Chest computed tomography showed wall thickening and stenosis in the main pulmonary artery as well as in both proximal pulmonary arteries. In order to differentiate between unusual CTEPH, vasculitis, and PAS, we performed right heart catheterization and pulmonary angiography. The mean pulmonary arterial pressure was 21 mmHg, and there was severe pulmonary artery stenosis. Thrombi on the pulmonary arterial wall lesions were observed in intravascular ultrasound and optical coherence tomography. Furthermore, the patient had a history of deep vein thrombosis. Therefore, we diagnosed unusual CTEPH. After 6 months of rivaroxaban anticoagulation therapy, a chest X-ray revealed a left lower lobe lung mass, and a positron emission tomography later showed hypermetabolic lesions in the main pulmonary artery wall, in both pulmonary arteries walls, in the lung parenchyma, and in the bones. A biopsy of the right proximal humerus lesion revealed undifferentiated intimal sarcoma. Pulmonary sarcoma is rare, but should be considered when differentially diagnosing main pulmonary artery wall thickening and stenosis. A positron emission tomography may aid in this diagnosis.

• Journal of Ship and Ocean Technology
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• 제4권1호
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• pp.28-36
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• 2000

Numerical simulation based on the superposition of ring waves generated by the linear periodic source distributions for the plunger type wave maker was accomplished. The characteristics of directional spreading function were investigated. Mirror images are also introduced to consider reflections of side-wall together with the reflection coefficient to account for the imperfect reflection from the real side wall in the long experimental towing tank. Unexpected spurious waves, resulting from the combined effect of finite breadth of segmented wave maker, wavelength and main wave maker, wavelength and main wave propagating direction, were observed in the line source method and also in the analysis of the directivity. The influence of spurious waves to the directional spreading function was also investigated.

• 한국전산유체공학회지
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• 제16권1호
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• pp.83-89
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• 2011

Laminar flow over a cube near a plane wall is numerically investigated in order to understand the effects of the cube-wall gap on the flow characteristics as well as the drag and lift coefficients. The main focus is placed on the three-dimensional vortical structures and its relation to the lift force applied on the cube. Numerical simulations are performed for the Reynolds numbers between 100 and 300, covering several different flow regimes. Without a wall nearby, the flow at Re=100 is planar symmetric with no vortical structure in the wake. However, when the wall is located close to the cube, a pair of streamwise vortices is induced behind the cube. At Re=250, the wall strengthens the existing streamwise vortices and elongates them in the streamwise direction. As a result, the lift coefficients at Re=100 and 250 increase as the cube-wall gap decreases. On the other hand, without a wall, vortex shedding takes place at Re=300 in the form of a hairpin vortex whose strength changes in time. The head of hairpin vortex or loop vortex, which is closely related to the lift force, seems to disappear due to the nearby wall. Therefore, unlike at Re=100 and 250, the lift coefficient tends to decrease more or less as the cube approaches the wall.

• 대한토목학회논문집
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• 제32권5B호
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• pp.301-312
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• 2012

본 연구에서는 규칙파를 대상으로 한 경사입사파 내습시 유공벽 전면에서의 파고분포를 파악하기 위해 평면수조를 이용한 수리실험을 수행하였다. 본 연구는 파랑의 전파특성에 있어 무공벽과 유공벽의 차이점과 유사점에 대해 검토하였으며, 특히 유공벽의 유수실 폭과 유수실내 격벽의 효과에 대해 검토하였다. 제체 전면의 상대파고는 유공벽인 경우와 무공벽인 경우에 매우 큰 차이가 있음을 보였으며, 유수실내 격벽은 연파의 발달을 억제시키는 것으로 나타났다.