• Title/Summary/Keyword: conducting property

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An Experimental Study on Fire Spreading External Wall of Buildings Using Dry Construction Method (건식공법을 이용한 건축물의 외벽 화재 확산의 실험적 연구)

  • Park, Jung-Woo;Cho, Nam-Wook
    • Fire Science and Engineering
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    • v.32 no.4
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    • pp.75-85
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    • 2018
  • The Grenpell tower fire in England in June of 2016 is a representative example of damage caused by a vertical fire spreading through external insulation. Organic insulation materials, which are widely used in external insulation, have the disadvantage that they have good insulation performance but are vulnerable to fire. Aluminum composite panels are used as exterior wall finishing materials, and plastics used in aluminum are regarded as the cause of vertical fire spread. Due to the steel frame used to secure the aluminum composite panel to the outer wall, a cavity is formed between the outer wall and outer wall finish. When a fire occurs on the outer wall, the flammable outer wall as well as the flame generated from the heat-insulating material spreads vertically through the cavity, resulting in damage to people and property. In Korea, material unit performance tests are carried out by the Ministry of Land, Infrastructure and Transport notice 2015 - 744. However, in the UK, the BS 8414 test is used to measure the vertical fire spreading time on the outer wall in real scale fire tests. In this study, the risk of external wall fire was evaluated in an actual fire by conducting a real scale wall fire test (BS 8414), which was carried out in Europe, using aluminum composite panels of semi-noncombustible materials suitable for current domestic standards. The purpose of this study was to confirm the limitations of material unit evaluation of finishing materials and to confirm the necessity of introducing a system to prevent the spread of outer wall fire through an actual scale fire test.

The Effect of Psychological Factors of Speeding Behavior Using a Driving Simulator (Focused on Speeding Intention) (차량시뮬레이터를 이용한 과속운전의 심리적 요인 연구 (과속의도를 중심으로))

  • Ryu, Jun-Beom;Sin, Yong-Gyun;Park, Je-Jin
    • Journal of Korean Society of Transportation
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    • v.29 no.1
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    • pp.39-46
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    • 2011
  • Speeding is a major cause of traffic accidents that affects the safety of pedestrians and harms drivers and their families, property and mental health. However, most researches on speeding behavior have been conducted by survey method, so the relationship between cause and effect is not clear. The reliability of the research cannot be carefully examined because most researches involve retrospective methods. It is clear that conducting experimental research is important for overcoming these limitations, but it is impossible to perform tests with real cars in real traffic situations due to the inability to control situational factors (e.g., other vehicles, traffic signal) which affect participants' behavior. A car simulator experiment was designed and the theory of planned behavior was applied to the experiment. Each participant was grouped and assigned to either high speeding intention group or low speeding intention group according to their levels of speeding intention and analyzed the difference of driving behavior indexes between two groups. The results revealed statistically significant differences between two groups on driving speed, speeding frequency, and accelerator pressure deviation. Finally, the limitations and the implications of this study were discussed.

Studies on Chemical Properties and Thermal Analysis of (Sr,M)FeO3-y System (M=Ca) ((Sr,M)FeO3-y계(M=Ca)의 화학적 성질과 열분석에 대한 연구)

  • Lee, Eun-Seok
    • Applied Chemistry for Engineering
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    • v.8 no.6
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    • pp.954-959
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    • 1997
  • The solid solutions of the $Sr_{1-X}M_XFeO_{3-y}$ (x=0.1, 0.2, 0.3, 0.4, 0.5, M=Ca) system having perovskite structures were prepared in air by heat treatment at 1473 K for 18hr. X-ray diffraction assigns cubic system for all the samples and shows that the lattice volume of each system decreases with increasing x value until x=0.3, but increases abruptly from x=0.4. The mole fractions of $Fe^{4+}$ ion($\tau$ value), the amounts of oxygen vacancy (y value) and finally nonstoichiometric chemical formulas for each composition were determined from Mohr salt analysis. TG/DTA thermal analysis (temperature range: 300~1173K) exhibits that 3-y values of the samples having x=0.1 and 0.2, decrease with temperature and increase almost reversibly with decreasing temperature. The samples of $x{\geq}0.3$, however, didn't show the reversible weight change and the 3-y values of them were nearly 2.5 in cooling process. Conductivities of each sample were varied within the semiconductivity range at relatively low temperature. And the conductivity at constant temperature decreases steadily with x value. The conduction mechanism of this ferrite system may be proposed as a hopping model of conducting electrons between the mixed valence states. At high temperature semiconductivity of each sample changed into metallic property.

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On the Study of Developement for Urban Meteorological Service Technology (도시기상서비스 기술 개발에 관한 연구)

  • Choi, Young-Jean;Kim, Chang-Mo;Ryu, Chan-Su
    • Journal of Integrative Natural Science
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    • v.4 no.2
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    • pp.149-157
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    • 2011
  • Urbanization of the world's population has given rise to more than 450 cities around the world with populations in excess of 1 million (megacity) and more than 25 so-called metacities with populations over 10 million (Brinkhoff, 2010). The United States today has a total resident population of more than 308,500,000 people, with 81 percent residing in cities and suburbs as of mid - 2005 (UN, 2008). Urban meteorology is the study of the physics, dynamics, and chemistry of the interactions of Earth's atmosphere and the urban built environment, and the provision of meteorological services to the populations and institutions of metropolitan areas. While the details of such services are dependent on the location and the synoptic climatology of each city, there are common themes, such as enhancing quality of life and responding to emergencies. Experience elsewhere (e.g., Shanghai, Helsinki, Tokyo, Seoul, etc.) shows urban meteorological support is a key part of an integrated or multi-hazard warning system that considers the full range of environmental challenges and provides a unified response from municipal leaders. Urban meteorology has come to require much more than observing and forecasting the weather of our cities and metropolitan areas. Forecast improvement as a function of more and better observations of various kinds and as a function of model resolution, larger ensembles, predicted probability distributions; Responses of emergency managers, government officials, and users to improved and probabilistic forecasts; Benefits of improved forecasts in reduction of loss of life, property damage, and other adverse effects. A national initiative to enhance urban meteorological services is a high-priority need for a wide variety of stakeholders, including the general, commerce and industry, and all levels of government. Some of the activities of such an initiative include: conducting basic research and development; prototyping and other activities to enable very--short and short range predictions; supporting and improving productivity and efficiency in commercial and industrial sectors; and urban planning for long term sustainability. In addition urban test-beds are an effective means for developing, testing, and fostering the necessary basic and applied meteorological and socioeconomic research, and transitioning research findings to operations. An extended, multi-year period of continuous effort, punctuated with intensive observing and forecasting periods, is envisioned.

Proposal of Construction System to prevent Dongbari Collapse by applying IT Convergence Technology (IT 융합기술을 적용한 동바리 붕괴사고 방지를 위한 건설공사 시스템 제안)

  • Jeon, Kyong-Deck;Shin, Seung-Jung
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.5
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    • pp.113-120
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    • 2020
  • Safety accidents, called industrial accidents in construction work, are causing a lot of casualties, property damage and social controversy in the event of an accident, causing the construction to lose public confidence. The risk of safety accidents at construction sites may continue to increase as the construction of high-rise, large-scale, and multi-purpose complex buildings has increased in recent years. In particular, the most frequently constructed apartment construction among reinforced concrete buildings is designed and constructed with a wall-like structure with no beams for each floor, while the lower floors are made of lamen with columns and beams. As a result, the transfer beam or transfer slab to withstand the upper load is installed on the upper part of the Ramen structure, so the system Dongbari, which is installed as a temporary material during concrete laying construction, may collapse at any time during plowing and curing. The purpose of this study is to apply IT convergence technology to prevent the collapse of the system Dongbari during concrete installation, and to apply many of the variables that may occur during construction on a case-by-case basis to check the stability of the system Dongbari and to propose a model of the anti-conducting prediction system.

A Study on Practical Method of Utility Curve for Deciding Priority Order of the Improvements in Traffic Safety Audit (교통안전진단 개선방안들의 우선순위 산정 연구)

  • Choi, Ji Hye;Kang, Soon Yang;Hong, Ji Yeon;Lim, Joon Beom
    • Journal of the Korean Society of Safety
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    • v.31 no.3
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    • pp.143-155
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    • 2016
  • Recently, a massive loss of life and property is occurring in Korea due to traffic accidents, with the rapid increase in cars. For improvement of traffic safety, the Korea Transportation Safety Authority intensively analyzes accident data in local governments with low traffic safety index, performs a field investigation to extract problems and offers local governments improvements for problems, by conducting the 'Special Survey of Actual Conditions of Traffic Safety' each year, starting 2008. But local governments cannot strongly push forward the improvement projects due to the limited budget and the uncertainty of the improvement plan effects. Therefore, this study suggested a model which applied the Utility concept to the AHP theory, in order to efficiently decide a priority of the improvement plans in accident black spots in consideration of the limited budget of local governments. The number of accidents in each spot for improvement and accident severity, traffic volume, pedestrian volume, the improvement project cost and the accident reduction effect were chosen as evaluation factors for deciding a priority, and data about the improvement plan costs and the accident reduction effects, traffic accidents and traffic volume in the spots to undergo the special research on the real condition of traffic accident in the past were collected from the existing studies. Then, regression analysis was carried out and the Utility Curve of each evaluation factor was computed. Based on the AHP analysis findings, this study devised a priority decision method which calculated the weight and the utility function of each evaluation factor and compared the total utility values. The AHP analysis findings showed that among the evaluation factors, accident severity had the biggest importance and it was followed by the improvement plan cost, the number of accidents, the improvement effect, traffic volume and pedestrian volume. The calculated utility function shows a rise in utility, as the variables of the 5 evaluation factors; the number of accidents, accident severity, the improvement plan effect, traffic volume and pedestrian volume increase and a fall in utility, as the variables of the improvement plan cost increase, since the improvement plan cost is included in the budget spent by a local government.

A Study on the Status and the Perception of Near Miss Reporting Activities in Domestic Manufacturing Industry (국내 제조업의 아차사고 발굴활동 현황 및 인식에 관한 연구)

  • Lee, Seok Ki;Park, Jungchul
    • Journal of the Korea Convergence Society
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    • v.12 no.12
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    • pp.287-294
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    • 2021
  • A near miss is an unplanned event that did not result in injury/illness, or property damage, but had potentials to do so. The importance of the near miss has been emphasized by many researchers and organizations. However, only a few studies have quantitatively approached the near miss from the viewpoint of safety culture. The purpose of this study is to investigate the current status of near miss reporting activities in manufacturing workplaces in Korea. It also aims to understand how the activities related with the safety culture and the occurrence of industrial accidents. To this end, a survey was conducted on manufacturing workplaces and the results were analyzed. As a result, there was a marked difference in the perception on near miss according to whether or not the near miss reporting activity was conducted. However, it was found that only 56% of the workplaces were carrying out the reporting activities. It was found that the number of near misses reported varied depending on the reward. Although no correlation could be found between whether or not the near miss reporting activities were carried out and the history of industrial accidents occurred, it was found that safety culture level was hier at the workplaces conducting the activities.

Recent Progress in Conductive Polymer-based Membranes (전도성 고분자 분리막의 최근 연구동향)

  • Park, Shinyoung;Patel, Rajkumar
    • Membrane Journal
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    • v.31 no.2
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    • pp.101-119
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    • 2021
  • The demand for clean water is virtually present in all modern human societies even as our society has developed increasingly more advanced and sophisticated technologies to improve human life. However, as global climate change begins to show more dramatic effects in many regions in the world, the demand for a cheap, effective way to treat wastewater or to remove harmful bacteria, microbes, viruses, and other solvents detrimental to human health has continued to remain present and remains as important as ever. Well-established synthetic membranes composed of polyaniline (PANI), polyvinylidene fluoride (PVDF), and others have been extensively studied to gather information regarding the characteristics and performance of the membrane, but recent studies have shown that making these synthetic membranes conductive to electrical current by doping the membrane with another material or incorporating conductive materials onto the surface of the membrane, such as allotropes of carbon, have shown to increase the performance of these membranes by allowing the adjustability of pore size, improving antifouling and making the antibacterial property better. In this review, modern electrically conductive membranes are compared to conventional membranes and their performance improvements under electric fields are discussed, as well as their potential in water filtration and wastewater treatment applications.

Uncertainty Analysis of BAG by GNSS Correction (해저지형 표면자료의 GNSS 보정방법에 따른 불확실도 연구)

  • OH, Che-Young;KIM, HO-Yong;LEE, Yun-Sik;CHOI, Chul-Uong
    • Journal of the Korean Association of Geographic Information Studies
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    • v.22 no.3
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    • pp.1-9
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    • 2019
  • In the recent marine sector, the development and standardization regarding S-100, which is the universal hydrographical data model standard for development of marine space information, was progressed, and for the effectiveness of marine chart production work and the multi-purpose use of water level data in S-100, S-102(Bathymetric Surface grid) standard development and various studies of BAG formats combined with water level and uncertainty, property information is being progressed. Since the water level information that is important in the operation of the ship is provided based on S-102, the calibration method of the location information when producing S-102 is an important factor in deciding the water level. In this study, the hydrographical surveying was conducted by piloting the standardized method for the production of S-102 in Korea, and have compared the accuracy of water level information according to the GNSS post treatment calibration method. As a result of comparing the water level in 2 places in the rocky terrain of the study area, the northern water level of Namu-do was shown as DL 0.79~0.83m, the eastern water level of Daeho-do was DL 12.63~12.91m, and the horizontal position errors of the intermittent sunshine water level were confirmed to be within 1m. As a result, the intermittent sunshine water level according to the location calibration method when producing the BAG was confirmed that it was in the available range for a ship's safe voyage. However, the accuracy verification for the location of the ship when conducting hydrographical surveying was judged that there is a need for a various additional study about regional characteristics and environment factor.

The Ming Castle Conservation Policy and the Creation of Historical and Cultural Environments (중국 '난징(南京) 명성곽(明城郭)'의 보존정책과 역사문화환경 조성)

  • Ryu, Ho Cheol
    • Korean Journal of Heritage: History & Science
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    • v.46 no.1
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    • pp.346-361
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    • 2013
  • Since the Ming Castle located in Nanjing was designated by the Government of China as a cultural property in 1988, the Nanjing city government has been conserving the castle according to its plan and thus restoring the historical and cultural values of Nanjing. The project is still in progress, and in this regard, a series of logistics have formulated and a lot of discussions have taken place. Likewise, Korea has been carrying out multidirectional policies to conserve and utilize castles lying throughout the country, appreciating the historical and cultural resources of castles lying throughout the country, and at the same time gets down to designation as the World Heritage. This study focused on how Nanjing, not only a castle city but also a historical city, had established a principle and legal foundation regarding the protection of the Ming Castle, especially on how the problems, which might continually arise in a process where a scheme reached a working stage, had been solved. The problem-solving process is expected to have great implications for Korea in a similar situation. Hereat, this study analyzed the project plans formulated seasonally and gathered data on practical operation by conducting interviews with hands-on workers. The results showed that Nanjing had carried out policies to utilize the castles as tourism resources by harmonizing cityscape and ecological environment, but that it well conserved castles without damaging cultural assets. The stereoscopic protection system for the Ming Castle, based on the consideration of historical and cultural environments, may provide practical and useful data for Korea's administration mapping out for a castle conservation policy and designation as the UNESCO World Heritage.