• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.166-166
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• 2017

금속 재료 중 철강은 기계적 특성이 우수하고 대량생산이 가능하여 선박, 건축, 자동차 등 다양한 분야에 기초재료로써 널리 사용되고 있다. 그러나 스테인리스강 등과 같은 일부 특수한 용도의 강을 제외하고는 부식환경에 취약한 특성을 가지기 때문에 내식성을 향상을 위한 표면처리에 관한 연구가 활발히 진행되고 있다. 가장 일반적으로 습식법(wet process)을 통해 표면상에 아연(Zn)을 도금해 사용하며, 아연이 자체적으로 포함한 희생양극(sacrificial anode) 및 차폐(barrier) 효과가 철강의 부식을 방지하게 된다. 하지만 산업의 고도화에 따라 더욱 가혹해진 노출환경으로 인해 고내식 강재에 대한 수요가 점차 증가하고 있으며, 아연코팅 층의 두께를 증가하여 내식성을 확보하는 방안은 미래 환경 및 자원적인 측면에서 근본적인 해결책으로 제시하기 어려움이 있다. 한편, 건식 프로세스(wet process)로 대별되는 PVD(physical vacuum deposition)에 의해 내식성을 향상시키고자 하는 연구들이 다양하게 진행되고 있다. 이것은 표면에 고순도 양질의 금속 막을 형성시킴으로써 외부환경과의 반응을 효과적으로 제어가 가능하며, 형성된 막은 그 물질의 고유 특성뿐만 아니라 제작 조건에 따른 표면의 기하학적 혹은 결정학적 구조에 의해 크게 영향을 받게 된다. 본 연구에서는 실용금속 중 이온화 경향이 가장 크고 산소와 반응하여 투과성이 작은 산화 피막 형성이 유리한 마그네슘(Mg)을 활용해 표면의 전기화학적 특성을 향상시켰다. 또한 금속 증착 중 진공도조절을 위해 도입되는 불활성 가스로 아르곤(Ar) 및 질소($N_2$)를 사용하여 표면에 형성한 막의 모폴로지 및 결정배향성이 내식성에 미치는 상관관계를 해석하고자 하였다. 실험방법으로 PVD법 중 비교적 간편하고 기초적인 지침을 제시하기 적합할 것으로 고려된 진공증착(vacuum evaporation)법을 이용해 아르곤 및 질소 분위기에서 진공도를 조절하며 용융아연도금상 Mg막을 형성하였다. 제작조건별 막의 기초 특성을 분석하기위해 SEM, EDS, XRD를 이용하였고, 결정배향성(crystal orientation) 분석을 위해 면간격(d-value)과 상대강도(relative intensity)를 확인하였다. 또한 내식성 평가로 염수분무(salt sprat test) 및 양극분극(anode polarization)을 각각 실시하였다. 실험결과에 따르면, Ar 및 $N_2$ 모두에서 가스압이 증가할수록 코팅층의 증착량은 적어지고 입상정(granular structure)의 모폴로지 형성 및 면간격과 상대강도가 증가하는 것이 확인되었다. 또한 쳄버 내 동일 진공도에서, $N_2$ 도입 시 Mg막은 더욱 치밀하고 미세한 입상정의 모폴로지로 형성되며 면간격과 상대강도는 더욱 증가한 것으로 나타났다. 내식성 평가에서 저진공 $N_2$ 조건에서 형성시킨 막이 가장 우수한 내식성이 나타났는데, 이는 상대적으로 불안정하고 반응하기 유리한 입계면적을 많이 포함한 입상정 모폴로지 및 표면에너지가 높은면의 면점유율 증가로 인해 외부환경과의 신속한 반응은 물론 안정적인 피막형성이 용이하였기 때문일 것으로 사료된다. 이상으로 Ar 및 $N_2$ 가스압 조건에 따른 고내식 Mg 막의 유효성을 확인하였고 향후 내식성을 향상시키는 방법으로 응용 가능할 것으로 생각된다.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.267-276
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• 2016

Objectives: This study, aims to examine the distribution characteristics of asbestos-containing building materials; risk assessment and area of distribution of asbestos-containing building materials depending on year of construction; building materials; types of building materials; and usage in public buildings in order to create fundamental data for safe management of public buildings. Methods: The asbestos investigation was conducted by an asbestos research institution from March to May 2014, targeting 41 public buildings which were subject to asbestos investigation in South Chungcheong-do Province. With respect to 381 presumed asbestos-containing materials, an investigation was conducted into whether they contained asbestos, asbestos type, content, year of construction, and use in the building were examined, and a risk assessment was performed. Results: Asbestos-containing building materials were used in 35 buildings(85.4%). Among them, 31(88.6%) were public buildings. Asbestos was detected in 73% of 381 suspected asbestos-containing materials, which were mostly ceiling materials (85.2%). The older the buildings, the more they showed a tendency to have a significantly higher risk assessment score. The ratio of average area with asbestos-containing building materials to total floor area was 57.6%, 44.1%, and 17.8% for buildings built in the 1980s, 1990s, and 2000s, respectively. This showed a tendency to be significantly higher with the age of the building. Conclusions: From the results above, it can be concluded that with the age of the buildings, the risk assessment score and the ratio of average area with asbestos-containing building materials to total floor area became significantly higher. Given the concern about the exposure to asbestos of residents and civil petitioners, safety management of older public buildings and measures for dismantling and removal of asbestos-containing building materials should therefore be urgently established.

• Fire Science and Engineering
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• v.28 no.6
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• pp.52-57
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• 2014

The present study suggests the fundamental method for the prediction time of the fire origin by analyzing the combustion phenomenon of inflammable material in the building structure. The heat release rate (HRR) with time variant is evaluated for the interphone as a inflammable material, which is opted from the fire incidents in the stairwell. the fire dynamics simulator (FDS ver. 6.1) is applied in order to analyze the difference of the smoke inflow time to the downstair from the fire event area with various fire pattern. The results show that the maximum inflow time difference for the case of the interphone made from ABS materials is about 4.93 times with the input conditions of heat flux values and the environment in the FDS for the fixed stairwell which composed of total volume $291.3m^3$, floorage $23.3m^2$ and the height of each floor 2.5 m. This research can be practical information for the application method of simulation scheme with experimental data to the fire Identification.

• Fire Science and Engineering
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• v.27 no.3
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• pp.38-46
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• 2013

Permanent water supply and water sprinkling systems are essential to protect major forests and facilities from forest fire. Back in 2005, Naksan Temple, a valuable cultural asset of Korea, was burned down in a forest fire that took place in Yangyang. This started a series of movements including installing water supply facilities and managing forests near important cultural assets. As for the existing facilities, however, they were installed without any standard guidelines for management and installation according to each constructor's specifications, which were based on the National Fire Safety Code 109. Unfortunately, this is not effective in protecting facilities from forest fires such as they have a small protection area, limited simultaneous sprinkling, and a difficult the movement of fire hose. Against this background, the study examines the condition of water supply facilities currently in use, identifies their deficiencies, and suggests how to improve the criteria for water supply service to effectively prevent forest fire. Specifically, three systems were proposed: Water Sprinkler Tower System for preventing spread of crown fires, and Forest Fire Hydrant System and Portable Water Spray System to be effective for suppressing surface fires. In addition, the standards on the performance and components of water pumps are also suggested.

• Fire Science and Engineering
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• v.25 no.4
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• pp.103-109
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• 2011

In this study, we calculated the smoke movement at the fire area of the refuge floor which has the refuge safety area in case of fire in the high rise building by using a computational fluid dynamics (CFD) code of FLUENT (ver. 13.0). The buoyancy plume was applied using the temperature and flow velocity which represent 10 MW heat release rate in order to describe the fire, and the smoke movement was predicted using a species conservation equation. The pressurization system of smoke control was adopted with smoke control damper in refuge safety area, at the result, it is confirmed that the damper capacity was enough to smoke control in which the flow rate of supply was applied 25 $m^3/s$ in the case of the door at fire area opened only, and 50 $m^3/s$ in the doors at the fire area and lobby both opened case. They were satisfied in NFSC 501-A. Even though the door of fire area closed, there were smoke leakages at the gap between the door and wall. In addition, the refugee could be isolated in the fire area when the door of fire area closed during smoke control in the case of using the high damper flow rate of supply, 50 $m^3/s$. Therefore the proper damper flow rate of supply are needed in order to prevent the damage of refugee and this study proposes the suitable condition of damper capacity according to refuge scenario.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.609-619
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• 2004

An investigation was conducted on the activities around Europe in order to solve the problem of the thermal bridging of steel studs, which had caused a significant disadvantage. This study included the following: diminishing the contact area between the studs and the sheathing, lengthening the heat transfer route, replacing the steel web with a less conductive material, and placing foam insulation in locations where the thermal shorts are most critical. Although energy efficiency is usually the focus of such foreign cases because their stud application is mostly limited to low-rise residential buildings, both structural and thermal performance are taken into consideration in this study because these target middle-story buildings. A hybrid stud composed of steel and polymer was also developed. This hybrid stud, which is 150 SL in size, is made of a galvanized steel sheet (SGC58) and a glass fiber reinforced polymer (GFRP) withepoxy bonding. A total of 32 specimens were manufactured. Its parameters comprise two types of connection detail,s: the thickness of steel (1.0mm and 1.2mm) and of the GFRP (4mm-4ply and 6mm-6ply), and the ratio of the length to the depth (L/D = 3, 6, 9, 12). Steel stud specimens with the same conditions were compared to the hybrid stud. The test revealed that in the case of the steel specimen with a thickness of 1.0mm, the maximum load of hybrid studs increased an average of 1.62 times comparedto that of the steel stud. In the case of the steel specimen with a thickness of 1.2mm, on the other hand, the average increase was 1.46times. All specimens showed full composite action until the collapse.

• Parasites, Hosts and Diseases
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• v.35 no.1
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• pp.9-17
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• 1997

During the period of 1933-1994, house dusts were collected from 65 homes at 10 different localities by operating electric vacuum cleaners. House dust mites were isolated from 10 g dust by applying the modified wet sieving method. Total 7,257 mites were collected and 23 species were identified. Among them, Demctophqgoines loyinaf (DF) was predominant (65. Soy) of the total) , followed by D. pteronvssinus (DP) (20.6%) and Tyrophagus nutrescentios (TP) (6.5%) . Rhizoglvphur robini, Sancqsscnin phvIlophogiann, Cheyletus trcussarti and Scheloribates latipes were the first findings from Korea. DF was predominant in Seoul (66.8%), Kwangju (63.6%), inland of Pusan (79.6%1, Inchon (96.5%), Taejon (83.9%), Chouju (87.15) and Chongiu (95.2%), whereas DP was predominant in Yongkwang-ub (72.5%) and Yongdo (island) of Pusan (64.9%), and TP in Chunchon (38.2%) The localities where DP and TP were predominant showed higher relative humidity in air (> 73% RH) . Among 62 study homes, DF, DP and TP were found in 24.6% of the homes, co-habitat of two species in 48.1% and one species in 27.3%. DF was predominant in 63.5% of the homes studied, DP in 29.6% and TP in 6.9%. In 10 g of the house dust, less than 99 mites were found in 49 homes (70.0%), 100-499 mites in 11 homes (15.7%), 500-999 mites in 3 homes (4.3%) and more than 1,000 mites in 2 homes (2.9%). No mite was found in 5 homes (7.1%). In order to evaluate environmental factors affecting the population density of house dust mites, house type, age of house construction, size of the house, number of the family and frequency of the cleaning were compared with the number of mites, and none of the above factors were statistically correlated with the mite density.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.1
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• pp.89-99
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• 2014

The current Development Impact Fee (DIF) Zoning Law allows Korean localities to designate the DIF Zone for the areas where there have been up-zoning in land-uses due to any minute additions and/or amendments in the existing clauses or provisions in the National Territory Planning Law as well as all other laws related to urban and regional planning. In reality, however, it is almost impossible to trace the sporadic and infinitesimal changes that might occur in every corner of the statutory clauses of a great number of planning related laws. This study, in an effort to overcome such practical difficulties, tries to chase the time-series zoning alterations in especially the consecutive land-use information layers of the Korea Land Information System (KLIS) as comparable analogues of the outcomes of the amendments in various planning laws. A study locality is chosen among the entire localities in the Capital Region based on the selection criteria dictated by the DIF Zoning Law such as the population- and building permit increase rate. It has been verified that the methodology suggested herein is practically applicable and successfully capable of extracting a number of DIF zones with considerable areal sizes, which could not have otherwise been possible. The consequences of this study, in this context, are expected to contribute to prevent the uncontrolled developments as the DIF Zoning Law itself was originally intended to achieve.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.4
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• pp.109-120
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• 2016

This study aims to assess vulnerability in urban thermal environments of Seoul by using indicators frequently used in previous studies as well as effective indicators for spatial planning like urban and environmental planning. For this purpose, fifteen indicators that influence urban thermal environments such as heat waves, urban heat island effects, and urban micro-climates were identified based on literature reviews. Indicators for presenting urban structure and spatial properties were included; for example, building volume as 'exposure to climate', buildings completed before 1980 as 'sensitivity', and green space areas as 'adaptive capacity'. Among them, twelve indicators were applied to assess vulnerability in urban thermal environments of Seoul by using a GIS spatial analysis combined with fuzzy logic. The results show that the Gangnam area is identified as more vulnerable to a heat environment as compared to the Gangbuk area. In the Gangnam area, Seocho-gu, Gangnam-gu, Dongjak-gu, Yeongdeungpo-gu, Gangseo-gu were relatively high in vulnerability, while Dongdaemun-gu, Gangbuk-gu, Gwangjin-gu, Jungrang-gu were relatively high in the Gangbuk area. Gwanak-gu, Dobong-gu, Eunpyeong-gu, and Nowon-gu, which include forested areas, have low vulnerability in the sectors of 'exposure to climate' and 'sensitivity' due to the impact of Gwanaksan and Bukhansan. However, some areas with high vulnerability like Seocho-gu and Gangnam-gu may have lower vulnerability if the indicator 'status of air conditioning' from the sector of 'adaptive capacity' is used. This study could support the establishment of a practicable thermal environment policy and spatial planning to reduce heat-related risks in the field of urban and environmental planning.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.208-216
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• 2019

Rural houses are losing their original shape as they mimic the spatial composition of urban houses. Therefore, the purpose of this study was to extract the design elements needed for rural housing by applying Christopher Alexander's "A PATTERN LANGUAGE" to Standard Rural-House Design (SRHD). The scope and method of research was to compare and analyze the standard designs (SD) produced and distributed by the 'Korea Rural Community Corporation' from 2009 to 2014. The research result is summarized as follows. 1) The housing layout in the SD ignored the site conditions of various rural areas. 2) Most of the houses were not actively planned, considering that they contain various activities of rural life. 3) There was no room for children and the kitchen was planned to integrate the interior into a flexible space in the form of L.D.K. 4) There was no space plan that could be used as both a leasable annex and office space for the farming community. 5) Many small area plans were made because of the SD plan for couples only in 2014. Although the rural environment and living patterns were ignored in the SD, the diverse pattern language provided by the pattern language was developed as a SD element for rural houses, which is the most suitable housing plan for the farmers' livelihood pattern.