• Land and Housing Review
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• v.2 no.4
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• pp.463-469
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• 2011

LH has installed sashes to the balcony to save energy and increase residential space. Then, it is very difficult to protect a condensation of vapor on the walls in the winter time, because the space is closed and the wall surface temperature becomes very low in a balcony. We have tried to get the optimal thermal design methods to reduce the condensation on the walls. The one of the chosen method is to make holes on the walls, and then the condensation shall be reduce because the dew point temperature will be lower due to the effect of dehumidify. In this case, it is just necessary to find as like that how many holes should be perforated through the wall, what's their size, and where is their positions. In this study, a computational fluid dynamics was applied to analyze the temperature, the pressure and the velocity distribution for an incompressible flow in the balcony spaces. And field tests were also carried out to get the data to compare to the simulation results. Finally the design criteria of the ventilation holes in the balconies was suggested by analysis of the computer simulation models.

• Steel and Composite Structures
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• v.25 no.4
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• pp.505-521
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• 2017

The steel plate shear wall with beam-only connected infill plate (SSW-BO) is an innovative lateral load resisting system consisting of infill plates connected to surrounding beams and separated from the main columns. In this research, the effects of perforation diameter as well as slenderness ratios of infill plates on the hysteresis behavior of SSW-BO systems were studied experimentally. Experimental testing is performed on eight one-sixth scaled one-story SSW-BO specimens with two plate thicknesses and four different circular opening ratios at the center of the panels under fully reversed cyclic quasi-static loading in compliance with the SAC test protocol. Strength, stiffness, ductility and energy absorption were evaluated based on the hysteresis loops. It is found that the systems exhibited stable hysteretic behavior during testing until significant damage in the connection of infill plates to surrounding beams at large drifts. It is also seen that pinching occurred in the hysteresis loops, since the hinge type connections were used as boundaries at four corners of surrounding frames. The strength and initial stiffness degradation of the perforated specimens containing opening ratio of 0.36 compared to the solid one is in the range of 20% to 30% and 40% to 50%, respectively.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.5
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• pp.335-341
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• 2014

Physical experiments were carried out to measure the wave force on the vertical walls of perforated breakwater considering several phases of a wave acting on the breakwater. The maximum horizontal wave force acting on each vertical wall was compared between single and double chamber caisson breakwater. The experimental data in this study showed that the total horizontal wave force for double chamber caisson was 9.6% smaller on average than that for single chamber caisson when the total chamber width was the same for both caissons. Such reduction of the wave force is due to the dissipation of wave energy at the porous middle wall, which is located between the porous front wall and non-porous rear wall.

• Advances in pediatric surgery
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• v.7 no.1
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• pp.59-63
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• 2001

The authors, over the last 6 months, have treated 2 patients with perforated typhlitis complicating acute lymphocytic leukemia (ALL) with good outcome. The first patient was a 13-year-old male who developed intermittent high fever, abdominal pain, abdominal distention and diarrhea during the course of maintenance chemotherapy. The peripheral leukocyte ranged from 230-470/$mm^3$. Serial ultra sonograms and CT scans demonstrated irregular thickening of the cecal and ascending colonic walls and subsequent ragged perforation of the posterior wall of the cecum. He survived after treatment by right hemicolectomy and aggressive supportive measures. The patient case was a 3 year-old female who developed intermittent high fever, right lower abdominal pain, a mass, and watery diarrhea during the course of maintenance chemotherapy. Serial ultra sonograms and CT scans demonstrated irregular thickening of the cecal wall (6-15mm in thickness) and subsequent small perforation of the posterior wall of the cecum with thick-walled localized abscess. She has recovered completely after aggressive medical management. We learned two lessons from our experience treating these patients:1) early diagnosis provided by a high index of suspicion and the use of ultra sonogram or CT scan is essential. And 2) although perforation is one of the surgical indications for the treatment of typhlitis, it is possible to manage the perforation nonoperatively in selected cases with localized abscess.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.6
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• pp.443-451
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• 2015

Design formula for estimating the wave loading on the perforated caisson having two wave chambers is yet available. In this study, the analysis results are presented with the experimental data for the wave force acting on such a breakwater model. Based on the experimental results, it was able to clarify the variation of wave action according to five different wave phases that are associated with peak wave loading at the three vertical walls. Then the force adjustment factor for double-chamber caisson was estimated, similarly as Takahashi and Shimosako (1994), which needs to be further validated with subsequent experiments and practical application in the field.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.6
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• pp.343-351
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• 2014

The reflection and transmission coefficients of waves due to perforated wall are mainly determined by both the porosity and wall thickness of the perforated wall and the period and nonlinearity of incident waves. Among them the wall thickness is very important because it affects the head loss coefficient and the inertia length of the wall. However, by employing the head loss coefficient derived for sharp crested orifice, the previous researches have neglected, or incorrectly considered the effect of wall thickness on the head loss coefficient. Even though it is considered, the effect of the inertia length is neglected in some empirical formulae. Thus, the effect of wall thickness on the reflection and transmission coefficients of waves is not properly considered. In this study comprehensive experiments are conducted for the perforated walls with various thicknesses, and the results are compared with those predicted by the empirical formulae. As a result it is found that the existing formulae can not properly consider the effect of wall thickness, and it is confirmed that a new formula which can correctly consider the effect of wall thickness on the head loss coefficient is necessary.

• Steel and Composite Structures
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• v.33 no.4
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• pp.569-581
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• 2019

Corrugated steel plate shear wall (CSPSW) as an innovative lateral load resisting system provides various advantages in comparison with the flat steel plate shear wall, including remarkable in-plane and out-of-plane stiffnesses and stability, greater elastic shear buckling stress, increasing the amount of cumulative dissipated energy and maintaining efficiency even in large story drifts. Employment of low yield point (LYP) steel web plate in steel shear walls can dramatically improve their structural performance and prevent early stage instability of the panels. This paper presents a comprehensive structural performance assessment of corrugated low yield point steel plate shear walls having circular openings located in different positions. Accordingly, following experimental verification of CSPSW finite element models, several trapezoidally horizontal CSPSW (H-CSPSW) models having LYP steel web plates as well as circular openings (for ducts) perforated in various locations have been developed to explore their hysteresis behavior, cumulative dissipated energy, lateral stiffness, and ultimate strength under cyclic loading. Obtained results reveal that the rehabilitation of damaged steel shear walls using corrugated LYP steel web plate can enhance their structural performance. Furthermore, choosing a suitable location for the circular opening regarding the design purpose paves the way for the achievement of the shear wall's optimal performance.

• Journal of Animal Science and Technology
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• v.44 no.1
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• pp.123-134
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• 2002

An experiment was conducted to establish the most suitable ventilation system for the enclosed nursery pig house in Korea, comparing four different ventilation systems ; i) air enters through perforated ceiling and exhausts through chimney (NA), ii) air enters through perforated ceiling and exhausts through side walls (NB), iii) air enters through perforated ducts and exhausts through side walls (NC) and iv) air enters through perforated ducts and exhausts through chimney(ND). The experiment was carried out during winter and summer separately. The experimental pigs were weaned at fourteen days old in winter (December-February) and at twenty one days old in summer (June-August). The main results of the experiment are as follows : A preliminary experiment showed that in the NC system during summer, air can reach all the pig rooms in the house and the air flow rates of the upper, middle (1.2 m height of the room) and low (at the height of pig stature) parts of the room were measured at 7.0-8.08, over 0.5 and over 0.2 m/s, respectively, which flow rates were much higher(p$<$0.05) than those in other system. At the minimum ventilation efficiency during winter, air flow rates of upper, middle and low parts of the room equipped with the NC system were detected at over 1, less than 0.5 and around 0.07 m/s, respectively. It is concluded that the separated ventilation system air-entering through ducts is the most suitable for the ventilation system of the enclosed nursery pig house and the exhausting system through side walls is more efficient for ventilation than the system through roof. Furthermore, to sustain proper temperature and reduce energy waste as well as heat consumption, a future research should be carried out to develop the environmental control system in relation to developing a heat regulator.

• Korean Journal of Veterinary Service
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• v.22 no.4
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• pp.393-398
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• 1999

This case occurred following accidental consumptions of toxic levels of feedstuffs in the Korean indigenous cattle which were pregnant for 3-6 months. Grossly, poorly defined bluish coloration in the ventral sac of the rumen, reticulum and omasum was visible on the surface of the stomach. The severely affected ruminal walls were perforated and blood-tinged exudate was observed and death followed due to acute diffuse peritonitis. There were copious amount of porridgelike rumen contents, which has a distinct fermentative odor. The epithelia were easily wiped off and hyperemic in patch. Histopathologically, chemical rumenitis with neutrophilic infiltration and opportunistic fungal infection was evident in the mucosa and submucosa. Multifocal necrotic foci with fungal hyphae on the liver and severe congestion on the renal medulla were noted. There was no evidence of heavy metal and aflatoxin Bl in the suspected feedstuffs. This case was diagnosed as acute carbohydate engorgement in cattle.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.29-32
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• 2008

The renewal of existing buildings rather than new construction has increased due to it's cost effective characteristics. Remodeling is also an environmentally-friendly approach that reduces the amount of waste in construction site. Remodeling can sometimes include partial destruction of the structural members of a building. In addition it is important that the buildings under going remodeling retrofitted to make themselves stable and meet up with the future demands for better structural performance. The objective of this paper is to present the test results and structural behavior of RC walls that are perforated and to introduce effective retrofitting methods by evaluating efficacy of passive retrofit and active retrofit. Passive retrofit and Active retrofit using carbon fiber sheets, steel plates and wire that are widely used for strengthening the main members of existing buildings. The test results showed that the failed specimens had shear fractures and that two different types of retrofit method had different effects on the strengths of each specimen.