• KIEAE Journal
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• v.8 no.1
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• pp.37-44
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• 2008

Though they have advantages in terms of aesthetic in modern architecture, however, rectangular-shaped towers causes being short of natural light due to deep interior space. There are compromised attempts to take advantages of each building shape selectively. As a result, we now witness the advent of Y-shaped, T-shaped, V-shaped and ㅈ-shaped buildings on the market. The mutative type of apartment houses usually faces southwest or southeast, which has lot of daylighting availability but anyhow, the proportion of the apartment houses which have a full south aspect. The need to verify the potential of daylighting in new building-block shapes exists. At the same time, the expansion of balcony area was legalized and thus, a visual buffer area does not exist any more. All-glass window wall on apartment houses without a balcony produces pretty harmful area with direct sunbeam. Recently, the refurbished version of conventional windows has been developed for the purposed of minimizing energy loss occurred around windows. This research initialized a series of research to deal with almost all on window wall for apartment houses. First of all, huge amount of already-designed examples of apartment houses have been analyzed in terms of floor plan, elevation, orientation and glazing materials.

• Structural Engineering and Mechanics
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• v.87 no.5
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• pp.487-498
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• 2023

Unreinforced masonry (URM) buildings are extensively adopted in many of the growing nations, particularly in India. Window or door openings are required for architectural or functional reasons, which pose a threat to the building's safety. The past earthquakes have shown that the seismic capability of these structures was very weak. Strengthening these unreinforced masonry walls using welded wire mesh (WWM) is one of the most commonly and economical methods. The present experimental study investigates the impact of openings on the shear behaviour of URM walls and the effectiveness of WWM in enhancing the shear performance of masonry wall. In the experimental program 16 specimens were cast, 8 unstrengthen and 8 strengthened specimens, under 8 unstrengthen and strengthened specimens, every 2 specimens had 0%, 5%, 10%, and 15% openings and all these walls were tested under diagonal compression. The results show that the shear carrying capacity reduces as the opening percentage increases. However, strengthening the URM specimens using WWM significantly improves the peak load, shear strength, ductility, stiffness, and energy dissipation. Furthermore, the strengthening of the URM walls using WWM compensated the loss of wall capacity caused by the presence of the openings.

• Advances in concrete construction
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• v.15 no.6
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• pp.377-389
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• 2023

In this study, an improved modular arch system with the lower arch space composed of a precast arch block and an outrigger was proposed as an underground culvert, and its applicability and structural behaviors were confirmed. This modular arch culvert structure with vertical walls was designed using precast blocks and by adjusting the placement spacing of concrete blocks to the upper part form an arch shape and the lower part form a vertical wall shape, based on previously researched modular arch systems. Owing to the vertical wall of the proposed modular arch system, it is possible to secure a load-carrying capacity and an arch space that can sufficiently resist the earth pressure generated from the backfill soil and loading on the arch system. To verify the structural characteristics, and applicability of the proposed modular precast arch culvert structure, a full-scale modular culvert specimen was fabricated, and a loading test was conducted. By examining its construction process and loading test results, the applicability and constructability of the proposed structure were analyzed along with its structural characteristics. In addition, its the structural predictability and safety for the applicability were evaluated by comparing the construction process and loading test results with the FE analysis results.

• Journal of Preventive Medicine and Public Health
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• v.31 no.2 s.61
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• pp.183-198
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• 1998

In order to determine the prevalence rate and find out the sexual difference of abnormal electrocardiographic findings manifested by computerized EKG, which is equipped with auto-analyzing function, a total of 2,083 electrocardiograms that were taken from population over 20 years-old from October 1996 to February 1997 were studied according to their age, gender and blood pressure. 1. Using the electrocardiography with auto-analyzing function, 33 kinds of abnormal findings were manifested. The prevalence rate of abnormal findings was 52.8% in male and 43.7% in female. Among them, the most common finding was sinus brady-cardia found in 17.6% of male and 15.4% of female. Left ventricular hypertrophy by voltage criteria, minimal voltage of left ventricular hypertrophy, left axis deviation and atrial fibrillation were more common in male than in female statistically. Both of nospecific T wave and ST segment abnormality were more common in female than in male statistically. 2. Thirty-three kinds of abnormal findings were manifested. They revealed one abnormal finding alone or combined with some other ones making 128 kinds of abnormal finding. The most common abnormal finiding that manifested alone was right axis deviation (100%), then myocardial ischemia (95.7%) the next. The most common abnormal finding that complexed with other abnormal findings were left anterior fascicular block(percentage of single manifestation, 26.2%) and nonspecific T wave abnormality(percentage of single manifestation; 32.9%). Also, combination of sinus bradycardia and minimal voltage of left ventricular hypertrophy, and combination of sinus bradycardia and left ventricular hypertrophy were included in 25th sequences of abnormal findings. 3. The prevalence rate of abnormal electrocardiographic findings were higher in older group, hypertensive group, and the group of higher systolic or diastolic pressure in both sexes. 4. Abnormal findings that commonly manifested with sinus bradycardia were voltage criteria or minimal voltage of left ventricular hypertrophy(38.6%): sinus arrhythmia(10.5%): nonspecific T wave or ST segment abnormality(18.4%) and first degree AV block(7.2%) in descending order. 5. The most common site which manifested myocardial ischemia was posterior and inferior wall with equal percentage of 23.4%. And then anterior wall(19.1%), and antero-lateral wall and septum with equal percentage of 10.6% was noted in descending order.

• Journal of the Korean GEO-environmental Society
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• v.13 no.3
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• pp.29-37
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• 2012

This study is to find out the characteristics of the behavior of Geosyntehtic Reinforced Retaining Earth Wall(GRREW) through the laboratory experiment with the reduced-scale model, and to verify the effect of reinforcement by materials of GRREW. The loading tests after combining nonwoven geosynthetic, re-bar mesh nets and drainage blocks respectively among the components of the GRREW were performed in three cases of their slopes. In the cases of the behavior analysis including all of the components of the GRREW, the maximum horizontal displacement was generated 8.4mm at the location of 0.57H in the slope of 1:0.3; 3.8mm at the location of 0.57H in the slope of 1:0.6; 3.6mm at the location of 0.86H in the slope of 1:1.0. On average, the horizontal displacements of the GRREW were reduced by 83.8% against those of the original slopes. Lastly, seepage analysis and slope stability analysis were performed by modelling section of field, to confirm the effect of installation of drainage block in GRREW. We can confirm to compare increasing the slope safe factor and decreasing ground water in accordance with drainage blocks.

• Steel and Composite Structures
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• v.15 no.1
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• pp.103-130
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• 2013

Fire performance and fire safety of high-rise buildings have become major concerns after the disasters of World Trade Center in the U.S. in 2001 and Windsor tower in Spain in 2005. Performance based design (PBD) approaches have been considered as a better method for fire resistance design of structures because it is capable of incorporating test results of most recent fire resistance technologies. However, there is a difficulty to evaluate fireproof performance of large structures, which have multiple structural members such as columns, slabs, and walls. The difficulty is mainly due to the limitation in the testing equipment, such as size of furnace that can be used to carry out fire tests with existing criteria like ISO 834, BS 476, and KS F 2257. In the present research, a large scale calorie meter (10 MW) was used to conduct three full scale fire tests on medical modular blocks. Average fire load of 13.99 $kg/m^2$ was used in the first test. In the second test, the weighting coefficient of 3.5 (the fire load of 50 $kg/m^2$) was used to simulate the worst fire scenario. The flashover of the medical modular block occurred at 62 minutes in the first test and 12 minutes in the second test. The heat resistance capacity of the external wall, the temperatures and deformations of the structural members satisfied the requirements of fire resistance performance of 90 minutes burning period. The total heat loads and the heat values for each test are calculated by theoretical equations. The duration of burning was predicted. The predicted results were compared with the test results, and they agree quite well.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.1
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• pp.47-53
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• 1997

Appropriation of partial substitution of concentrate mixture by urea-molasses-mineral block (UMMB) lick supplements for 20 lactating crossbred cows in 2nd and 3nd lactation was studied. Animals fed on wheat straw ad lib. and Berseem (Trifolium alaxandrium) fodder @ 1.5 kg/d on dry matter basis. Animals of control group were given concentrate supplement, while in treatment groups 10% of the concentrate requirement was substituted with 3 different types of UMMB lick type A ($T_1$), type B ($T_2$) and type C ($T_3$). CP content of the ration was 15%. Total dry matter intake (DMI) was about 1.0 kg/kg of fat corrected milk (FCM) yield and was not significantly different between control and treatment groups. Digestibility of neither proximate principles nor cell wall constituents were deviated on UMMB licks partial supplementation. FCM yield was increased by 140, 410 and 460 g/d, in $T_1$, $T_2$ and $T_3$, respectively, in comparison to control group but differences were statistically invalid. Though fat per cent was reduced, fat yields were remain constant among treatments. Milk composition was unaltered except significant difference (p < 0.01) in non-protein nitrogen (NPN) content. Gross-N and digestible-N conversion was significantly higher (p < 0.01) with $T_1$, $T_2$ and $T_3$ than control group. Energy utilization efficiency for milk production was only 36%. Result demonstrated that UMMB licks could be partial supplemented up to 10% of the concentrate requirement of crossbred cows yielding on an average 14kg/d without any adverse effect on feed intake, nutrient utilization and mild production. Comparatively, UMMB lick type B and C was proved better than type A and also economically viable.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.590-593
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• 2009

To identify the detailed 3D flow characteristics of a model scramjet engine, a unified 3D numerical analysis was performed. The numerical domain of concern includes the entire flow path of the model scramjet engine extending from the intake to the nozzle exhaust. Turbulent models($k-{\omega}$ SST and low Reynolds number k-e with Sarkar model) were applied with comparison of experiment result. Intake side wall's effect on flow characteristics was analyzed in view points of flow quality at inlet duct and near the flame holder as well. The code is paralleled with multi-block feature using MPI(Massage Passing Interface) library to speed up the 3D calculation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.205-214
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• 2010

Masonry structures have been used throughout the world for the construction of residential buildings. However, from a structural point of view, the masonry material is characterized by a very low tensile strength. Moreover, the bearing and shear capacity of masonry walls have been found to be vulnerable to earthquakes. In this study, to improve the seismic performance of masonry walls, hexagonal blocks were developed and six masonry walls made with hexagonal block were tested to failure under reversed cyclic lateral loading. This paper focuses on an experimental investigation of different types of wall with hexagonal blocks, i.e. walls with different hexagonal blocks and with different reinforcing bar arrangements, subjected to applied cyclic loads. The cracking, damage patterns and hysteretic feature were evaluated. Results from the hexagonal masonry wall were shown more damage reduction and less brittle failure in comparison to the existing rectangular masonry walls.

• Journal of Radiation Protection and Research
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• v.42 no.3
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• pp.141-145
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• 2017

Background: The concrete walls inside the vaults of cyclotron facilities are activated by neutrons emitted by the targets during radioisotope production. Reducing the amount of radioactive waste created in such facilities is very important in case they are decommissioned. Thus, we proposed a strategy of reducing the neutron activation of the concrete walls in cyclotrons during operation. Materials and Methods: A polyethylene plate and B-doped Al sheet (30 wt% of B and 2.5 mm in thickness) were placed in front of the wall in the cyclotron room of a radioisotope production facility for pharmaceutical use. The target was Xe gas, and a Cu block was utilized for proton dumping. The irradiation time, proton energy, and beam current were 8 hours, 30 MeV, and $125{\mu}A$, respectively. To determine a suitable thickness for the polyethylene plate set in front of the B-doped Al sheet, the neutron-reducing effects achieved by inserting such sheets at several depths within polyethylene plate stacks were evaluated. The neutron fluence was monitored using an activation detector and 20-g on de Au foil samples with and without 0.5-mm-thick Cd foil. Each Au foil sample was pasted onto the center of a polyethylene plate and B-doped Al sheet, and the absolute activity of one Au foil sample was measured as a standard using a Ge detector. The resulting relative activities were obtained by calculating the ratio of the photostimulated luminescence of each foil sample to that of the standard Au foil. Results and Discussion: When the combination of a 4-cm-thick polyethylene plate and B-doped Al sheet was employed, the thermal neutron rate was reduced by 78%. Conclusion: The combination of a 4-cm-thick polyethylene plate and B-doped Al sheet effectively reduced the neutron activation of the investigated concrete wall.