• Korean Journal of Materials Research
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• v.28 no.7
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• pp.398-404
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• 2018

Fatigue crack growth retardation of 304 L stainless steel is studied using a neutron diffraction method. Three orthogonal strain components(crack growth, crack opening, and through-thickness direction) are measured in the vicinity of the crack tip along the crack propagation direction. The residual strain profiles (1) at the mid-thickness and (2) at the 1.5 mm away from the mid-thickness of the compact tension(CT) specimen are compared. Residual lattice strains at the 1.5 mm location are slightly higher than at the mid-thickness. The CT specimen is deformed in situ under applied loads, thereby providing evolution of the internal stress fields around the crack tip. A tensile overload results in an increased magnitude of the compressive residual stress field. In the crack growth retardation, it is found that the stresses are dispersed in the crack-wake region, where the highest compressive residual stresses are measured. Our neutron diffraction mapping results reveal that the dominant mechanism is by interrupting the transfer of stress concentration at the crack tip.

• Fire Science and Engineering
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• v.16 no.4
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• pp.7-14
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• 2002

The diffusion characteristics of the smoke by effect of an ascending air movement in a local part of the room where heat generated was studied. How the smoke move in the limited parts of the room at which heat generated was studied through 3 cases altering locations of inlet and outlet of ventilated air and heat generated by CFD(Computational Fluids Dynamics) method. It was found that 1. Similar distribution of air velocity, air temperature and smoke concentration appeared in the case of upper left inlet and lower right outlet and the case of lower inlet and upper right outlet. 2. Distribution of temperature and smoke concentration was 0∼0.3, 0.06∼0.14 in the case of lower left inlet and upper right outlet. 3. the location of heat generation did not influence on the temperature distribution, but influence on the distribution of smoke concentration.

• Wind and Structures
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• v.30 no.3
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• pp.219-229
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• 2020

Net pressures on roofs and walls of buildings are dependent on the internal and external pressure fluctuations. The variation of internal and external pressures are influenced by the size and location of the openings. The correlation of external and internal pressure influences the net pressures acting on cladding on different parts of the roof and walls. The peak internal and peak external pressures do not occur simultaneously, therefore, a reduction can be applied to the peak internal and external pressures to obtain a peak net pressure for cladding design. A 1:200 scale wind tunnel model study was conducted to determine the correlations of external and internal pressures and effective reduction to net pressures (i.e., net pressure factors, F_C) for roof and wall cladding. The results show that external and internal pressures on the windward roof and wall edges are well correlated. The largest ${\mathcal{C}}_{{\check{p},net}$, highest correlation coefficient and the highest F_C are obtained for different wind directions within 90° ≤ θ ≤ 135°, where the large openings are on the windward wall. The study also gives net pressure factors F_C for areas on the roof and wall cladding for nominally sealed buildings and the buildings with a large windward wall opening. These factors indicate that a 5% to 10% reduction to the action combination factor, K_C specified in AS/NZS 1170.2(2011) is possible for some critical design scenarios.

• Journal of the Korean housing association
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• v.16 no.4
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• pp.73-80
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• 2005

A high-rise residential building experienced stack effect problems during the winter such as difficulties in opening residential entrance doors and whistling noise from elevator doors generated by airflow. Field measurements were carried out on the building and the problems were verified by the analysis of the measurement results from three points of view: the total stack pressure difference, pressure distribution on each floor, and the location of the neutral pressure level. Based on the analysis of the three key parameters, possible solutions were proposed, such as zoning vertical shafts, lessening the airflow from the entrance doors on basement floors and lobby floor by installing vestibules, improving the airtightness of exterior walls, and installing separation doors where the problems occur. Simulations of proposed solutions were conducted and the effects of reducing the pressure difference were evaluated. Stack effect problems in a high-rise residential building were verified through field measurements and could be mitigated by the solutions which were drawn from the analysis of the field measurements and the simulation results.

• Korean Institute of Interior Design Journal
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• v.13 no.5
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• pp.215-222
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• 2004

Buildings' outward appearances, sidewalks, and street lights have long been regarded as important factors identifying the street landscape of a city. On the other hand, the interior spaces of a building have been known to have less correlation with street landscape. This paper, which did not use standardized urban street landscape application methods, attempts, based on an experiment involving Pimatgol, to prove that small changes in interior design influence the street landscapes of cities and even provide new vigorousness. Pimatgol is a type of village that still possesses a traditional Korean lyrical atmosphere. This paper also attempts to, with the use of a physical model and a digital simulation of small changes interior design, such as changes in materials, size of the opening, location of furniture, or a change of lights, uncover positive changes in street landscape. Computer simulation is one of the extraordinarily useful techniques to predict lighting performance, changing interior space and present visual image. As a result, this study can be a valuable guideline for the future streetscape reform project to lead the demanding effects of the interior space.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.866-871
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• 2006

Recently according to the fashion of well-being, the case study of under floor heating system type for residential space is increasing. Specially double slab floor system can make several roles as reducing the acoustic noises and also supplying fresh air through the gap. So in present study floor heating performance was examined with various location of the space in the case of floor supply air and ceiling supply air. In both cases return air went out through ceiling opening. As one of the result is that when using the heat pipe type floor heating system the temperature difference between supply and return water was $15.2^{\circ}C$, but in case of commercial type floor heating system the temperature difference was $5.3^{\circ}C$ when the supply water temperature was $50^{\circ}C$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.6
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• pp.890-897
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• 2003

This paper compares engineering estimation schemes of C＊ and creep COD for circumferential and axial through-wall cracked pipes at elevated temperatures with detailed 3-D elastic-creep finite element results. Engineering estimation schemes included the GE/EPRI method, the reference stress method where reference stress is defined based on the plastic limit load and the enhanced reference stress method where the reference stress is defined based on the optimized reference load. Systematic investigations are made not only on the effect of creep-deformation behaviour on C＊ and creep COD, but also on effects of the crack location, the pipe geometry, the crack length and the loading mode. Comparison of the FE results with engineering estimations provides that for idealized power law creep, estimated C＊ and COD rate results from the GE/EPRI method agree best with FE results. For general creep-deformation laws where either primary or tertiary creep is important and thus the GE/EPRI method is hard to apply, on the other hand, the enhanced reference stress method provides more accurate and robust estimations for C* and COD rate than the reference stress method.

• Journal of the Korea Safety Management & Science
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• v.23 no.1
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• pp.31-38
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• 2021

port is the intersection of highway, railway, waterway and other transportation modes, and is the key to realizing integrated transportation. There are many excellent ports around the Tumen River Region. With the obvious location advantages, Tumen River Region is an important part of Tumen River regional cooperation and development, and is the key to realizing the "borrow port to sea", which is raised in "China Tumen River regional cooperation and development planning outline -- regard Changjitu area as the development and opening leading area" (referred to as "planning outline"). This paper focus on the main ports in the Tumen River region, taking them as the research object. Furthermore, the paper makes the strategic plan for the port cluster in the Tumen River region as well as puts a collaboration scheme is proposed by analyzing the research reviews of the Tumen River region and the present situations of the main ports.

• Journal of architectural history
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• v.28 no.4
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• pp.17-26
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• 2019

After opening Suwon railway station in 1905, a new road was constructed between Suwon station and Paldalmun(the South gate). It was the starting point to change urban structures of Suwon and shape the new city scape. In 1914, administrative districts of Suwon were reorganized. Suwon-myeon (township, a subdivision of Suwon-gun) was promoted to Suwon-eup(town) in 1931. Suwon-eup expanded its territory and changed the address system from 'li(里)' system to Japanese address system, 'Jeong(町)' in 1936. From 1920s, road system was changed and transformed Suwon's urban structures. A straight road was built from Jongro intersection to Janganmun(the north gate) in 1928. Another straight road was constructed between Suwon station to Padamun in the early 1930s. Public office buildings used the Hwa Seong HaengGung(華城行宮) and some of building moved to new location with new buildings. Main buildings of most schools in Suwon were reconstructed since 1930s. Commercial buildings and stores were sprung up and had their own characteristics by region. Around Suwon station, there are more hotels and restaurants than other areas. Rearranging administrative areas, developing road system and new buildings transformed Suwon's spatial structures. Constructing new roads formed a straight road passing through Suwon. After reorganizing administrative areas, this road turned to be the central axis of Suwon. Buildings in new style on the axis made the modern cityscape in Suwon.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.10
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• pp.1427-1435
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• 2001

Air movement in wokplaces, whether resulting from a forced ventilation system or naturally occurring airflow, has a significant impact on occupational health. In a huge shipbuilding factory building, typical harmful factors such as fume or vaporized gas from welding and cutting of steel plates, and dusts from grinding give unpleasant feeling. From field data survey, the yearly dominant, wind directions for the shipbuilding factory building tested were northwest, northeast and southeast Among the three wind directions, the ventilation improvement was the worst for the northeastern wind. This study was focused on location of the opening vents in order to utilize the natural ventilation effectively. Instantaneous velocity fields inside the 1/1000 scale-down factory building model were measured using a 2-frame PIV system. The factory building model was embedded in an atmospheric boundary layer simulated in a wind tunnel. The modified vents improve the internal Ventilation flow with increasing the flow speed more than two times, compared with that of present vents.