• Title/Summary/Keyword: Fire patterns

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Development of Thermal Precursor DB for Partial Disconnection and Poor Contact on Electrical Wire (배선에서의 반단선 및 접촉불량에 대한 열적 전조 DB구축)

  • Kim, Doo-Hyun;Kim, Sung-Chul;Lee, Jong-Ho;Kang, Dong-Kyu
    • Journal of the Korean Society of Safety
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    • v.24 no.2
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    • pp.30-36
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    • 2009
  • This paper aims at the precursor analysis and DB development of electrical fires based on thermal and current signals for partial disconnection and poor contact on electric wires through experiments and simulations. Also, DB system required for developing the precursor DB with these data was studied and designed. Firstly, in case of partial disconnection, characteristics were derived and analyzed by experiment and electrical-thermal finite element method(Flux 3D) on the model wires which consist of VCTF and IV electric wires. Based on the characteristics, About 351 partial disconnection precursor patterns were generated by the thermal analysis for electric wire according to deterioration time under normal state and 200% overload state of rated current. Secondly, in order to develop poor contact precursor patterns, temperature value and the current signal were considered. In simulating the poor contact situation on connector area of MCCB, connection torque was changed. Through the experimental analysis, about 251 poor contact precursor patterns were generated. Finally, Using thermal precursor patterns obtained by partial disconnection and poor contact, electrical fire thermal precursor DB was developed.

Spatio-Temporal Analysis of Forest Fire Occurrences during the Dry Season between 1990s and 2000s in South Korea (1990년대와 2000년대 건조계절의 산불발생 시공간 변화 분석)

  • Won, Myoung-Soo;Yoon, Suk-Hee;Koo, Kyo-Sang;Kim, Kyong-Ha
    • Journal of the Korean Association of Geographic Information Studies
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    • v.14 no.3
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    • pp.150-162
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    • 2011
  • For the period between 1991 and 2009, the annual average of 448 forest fires occurred in Korea. Above all, approximately 94% of the total fires frequently occurred during the spring and fall seasons. Therefore, we need to minimize the damage of forest fire and manage them systematically. In this study, we analyzed the spatio-temporal distribution patterns for the frequency of forest fire occurrences by each city and gun during dry season between 1990s and 2000s using GIS. Then we compared to analyze the frequency of forest fire occurrence by ten-day intervals in 2000s with that in 1990s. As a result of analysis, early April showed the highest frequency of forest fire occurrence in both 1990s and 2000s. Compared to the 1990s and 2000s, the regional change of forest fire showed the most frequent fire events around Chungcheong province. Especially extra 27 fires increased in Daejeon city, and the second most frequent fire had more than 10 fires in Jeolla province and Incheon. However, the number of fire frequency decreased by 12 fires at the end of April in Hongcheon-gun(the province of Gangwon). This is the largest drop over the study period. We consider that this paper will utilize usefully to establish regional counterplan for forest fire prevention by understanding regional forest fire patterns from seasonal change.

A Study on the Three Yin Diseases(三陰病) in the 『Shanghanlun(傷寒論)』 -Focusing on Prognosis Analysis- (『상한론(傷寒論)』 삼음병(三陰病)에 대한 연구(硏究) - 예후 분석을 중심으로 -)

  • Park, Sang-Kyun;BANG, Jung-Kyun
    • Journal of Korean Medical classics
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    • v.34 no.1
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    • pp.47-65
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    • 2021
  • Objectives : An accurate judgment of prognosis when treating diseases is crucial. While the 『Shanghanlun(傷寒論)』 deals with the prognosis of the Three Yin Diseases with great importance, full-scale studies have been lacking. This paper aims to study the Three Yin Diseases with a focus on prognosis analysis. Methods : Among the Three Yin Disease verses, those that could provide clues to prognosis were selected and analysed. Conclusions & Results : When Yang pulse patterns such as long(長脈)·floating(浮脈)·rapid(數脈) pulses and Yang symptoms such as fever, vexing heat, mild perspiration, thirst, warmth in hands and feet are present in Yin disease, it could be taken as signs of Yang Qi restoration. In these situations, Yin Cold pattern such as diarrhea and reversal cold disappear and the prognosis is positive. However, despite Yang pulse patterns and symptoms, there are cases where diarrhea happens as a result of cold dampness being eliminated due to Yang Qi restoration. Also, when Yang Qi starts communicating smoothly after its restoration in the Three Yin Diseases, perspiration can happen. When diarrhea and reversal cold, which are patterns of Yin Cold get worse, with pulse patterns such as unfelt(脈不至)·replete(實脈)·fulminating(脈暴出) pulses, false heat symptoms such as fever and hot flashes happen, accompanied with Yang Qi depleted symptoms such as inability to lie down due to agitation, continuous perspiration, sore throat, dyspnea, and exaggerated breathing happen. When fast pulse, fever, and perspiration are present due to depression and stagnation of ministerial fire, symptoms such as bloody stool with pus, purulent abscess, sore throat, and inability to lie down due to agitation show, which signal negative prognosis. In bad cases of Reverting Yin Disease, there is continuous diarrhea and bloody stool with pus, which can be due to either Kidney Yang deficiency or depression and stagnation of ministerial fire. It could also be caused by excessive heat.

A Simulation Model for the Study on the Forest Fire Pattern (산불확산패턴 연구를 위한 시뮬레이션 모델)

  • Song, Hark-Soo;Jeon, Wonju;Lee, Sang-Hee
    • Journal of the Korea Society for Simulation
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    • v.22 no.2
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    • pp.101-107
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    • 2013
  • Because forest fires are predicted to increase in severity and frequency under global climate change with important environmental implications, an understanding of fire dynamics is critical for mitigation of these negative effects. For the reason, researchers with different background, such as ecologists, physicists, and mathematical biologists, have developed the simulation models to mimic the forest fire spread patterns. In this study, we suggested a novel model considering the wind effect. Our theoretical forest was comprised of two different tree species with varying probabilities of transferring fire that were randomly distributed in space at densities ranging from 0.0 (low) to 1.0 (high). We then studied the distributional patterns of burnt trees using a two-dimensional stochastic cellular automata model with minimized local rules. We investigated the time, T, that the number of burnt trees reaches 25% of the whole trees for different values of the initial tree density, fire transition probability, and the degree of wind strength. Simulation results showed that the values of T decreased with the increase of tree density, and the wind effect decreased in the case of too high or low tree density. We believe that our model can be a useful tool to explore forest fire spreading patterns.

A Study on the Performance and the Improving Methods of the Building Fire Compartment under the Domestic Fire Safety Regulations (국내 방화규정에 따른 건축물 방화구획 성능 및 개선방안에 관한 연구)

  • Chun, Woo-Young;Lee, Kwang-Won;Lee, Ji-Hee;Kim, Wha-Jung
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2008.04a
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    • pp.19-24
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    • 2008
  • Recently, the buildings have gradually become higher, more massive and more complex with high growth of economy and varieties of the patterns of people's living. Therefore we study a performance and Improving Methods of the fire compartment as a measure to minimize the damage of the people and property from the fire. Currently, under the economic crisis situation, we do not consider about prevention of disaster safety enough; safety investment evasion, safety carelessness, and management relaxation etc. Also in the aspect of regulation system, industrial technology and plan engineering, Korean techniques of preventing fire disasters are far behind of other advanced nations. At this point, we are in need of improving about it. When considering like this situation, we need more studies on the practical improvement in order to assure fire prevention for buildings. The fire compartment prevent from magnifying the fire to the wide area by compartment into specific area. From this, it is possible to minimize fire damage and property and secure emergency exit for life safety. This fire compartment has primary function to extinguish fire easily, and the openings and penetrations are important passage which makes the smoke and fire go away from the fire area to the contiguous space. This study suggests improving methods of domestic fire compartment efficiency standard through comparative analysis of overseas advanced provision and domestic provision about base element of the building fire prevention.

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Study on Flow and Smoke Behaviors on in Longitudinal Tunnel (장대 터널에서의 배연방식에 따른 기류 및 연기거동 연구)

  • Kim, Won-Tae;Choi, Man-Yong;Park, Jeong-Hak;Chae, Kyung-Hee
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.1521-1527
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    • 2009
  • This study is aimed to analyze the floe patterns and thermal characteristics by computer simulation under the variations of fire strength for the logitudinal tunnel, from which flow and heat distributions are predicted in the longitudinal tunnel. Through the results of numerical computations, followings are found; one is that the volume flow rate is discontinuously increasing as closer to fire location, and the other is that a critical design to get the faster flow rate is required because of existence of backlayer flow for the high fire strength in view of safety for the people in fire of the tunnel.

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Fire Simulation Study and Tunnel Ventilation of Requirement in the Longitudinal Tunnel. (In Yimgo-4th Tunnel) (종류식 터널내 소요 환기량에 의한 터널환기 및 화재 시뮬레이션 연구 ( 임고 4 터널 ))

  • Chae, Kyung-Hee
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1378-1385
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    • 2008
  • This study is aimed to analyze the flow patterns and thermal characteristics by computer simulation under the variations of fire strength for Daegu-Pahang Yimgo-4th tunnel, from which flow and heat distributions are predicted in the longitudinal tunnel. Though the results of numerical computations, followings are found; one is that the volume flow rate is discontinuously increasing as closer to fire location, and the other is that a critical design to get faster flow rate is required because of existence of backlayer flow for the high fire strength in view of safety for the people in fire of the tunnel.

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A Study on the Principles of Prescriptions of the King Fire and the Premier Fire of Saam Acupuncture (사암침법(舍岩鍼法) 화열문(火熱門)의 군화방(君火方)과 상화방(相火方)에 대한 연구)

  • Sagong, Hee chan;Lim, Lark cheol;Kang, Jung Soo
    • Journal of Haehwa Medicine
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    • v.13 no.1
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    • pp.27-38
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    • 2004
  • Saam acupuncture has an evident principles of prescription based on acupuncture tonification and purgation of Nan-gyeong but many prescriptions of Saam acupuncture are not typical patterns. Therefore it is difficult to understand principles of those prescriptions. Understanding the principles of any prescription means understanding the physiology and pathology of that prescription and it have an important role in selecting the best prescription and taking the most effective treatment. This paper studies principles of prescriptions of the king fire and the premier fire. The theoretical authorities of analysis are Nan-gyeong, works of Joo dan-gye and Li dong-won and Uihakimmun. The damage of fire to mentality is very intensive and severe. The prescriptions of the king fire and premier fire have a good effect on diseases by fire. The fire of human body are two types, the king fire and the premier fire but the water of human body is only one and then inferior to fire. The fire superior to the water is unstable and the fire influences rapidly and intensively on four elements, wood, earth, metal, water. So the control of the water is the key to treat the disease by fire. Considering the attack and the treatment of disease, heart and liver are attacked with a disease by fire in its early stage and kidney and lung are the key to treatment. Consequently the pathology of the disease by fire is corresponding to the theory- Yang Sufficient, Yin Deficient- of Joo dan-gye. It seems that the theory of Joo dan-gye influenced on the medical theory of Saam Acupuncture. On that account I believe that the study of medical theories of the Geum and Won Dynasty that various medical theories appeared is very available.

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Post-fire Repair of Concrete Structural Members: A Review on Fire Conditions and Recovered Performance

  • Qiu, Jin;Jiang, Liming;Usmani, Asif
    • International Journal of High-Rise Buildings
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    • v.10 no.4
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    • pp.323-334
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    • 2021
  • Concrete structures may rarely collapse in fire incidents but fire induced damage to structural members is inevitable as a result of material degradation and thermal expansion. This requires certain repairing measures to be applied to restore the performance of post-fire members. A brief review on investigation of post-fire damage of concrete material and concrete structural members is presented in this paper, followed by a review of post-fire repair research regarding various types of repairing techniques (FRP, steel plate, and concrete section enlargement) and different type of structural members including columns, beams, and slabs. Particularly, the fire scenarios adopted in these studies leading to damage are categorized as three levels according to the duration of gas-phase temperature above 600℃ (t600). The repair effectiveness in terms of recovered performance of concrete structural members compared to the initial undamaged performance has been summarized and compared regarding the repairing techniques and fire intensity levels. The complied results have shown that recovering the ultimate strength is achievable but the stiffness recovery is difficult. Moreover, the current fire loading scenarios adopted in the post-fire repair research are mostly idealized as constant heating rates or standard fire curves, which may have produced unrealistic fire damage patterns and the associated repairing techniques may be not practical. For future studies, the realistic fire impact and the system-level structural damage investigation are necessary.

Thermal Characteristics of Foams and Discharge of Fire-Protection Foam Spray Nozzle (폼 분무 노즐 방사 분포 및 폼의 열적 특성 연구)

  • Kim, Hong-Sik;Kim, Youn-Jea
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.1 s.232
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    • pp.151-158
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    • 2005
  • A characteristic of discharge for a foam spray nozzle with various parameters was investigated. The discharge patterns from a fire foam spray nozzle are important to evenly spray over a maximum possible floor area. Two parameters of a foam spray nozzle were chosen, and compared with those from the standard one. Also, in order to evaluate the performance of discharged foam agents used to protect structures from heat and fire damages, the thermal characteristics of fire-protection foams were experimentally investigated. A simple repeatable test for fire-protection foams subjected to fire radiation was developed. This test involves foam generation equipment, a fire source for heat generation, and data acquisition techniques. Results show that the bubble size of foam is increased by large inside diameter of orifice or closed air hole, but phenomenon of discharge angle and expansion ratio is opposite. For the case of the open air hole, liquid film of a circular cone discharges with formation, growth, split and fine grain. In case of the closed air hole, a pillar of foam solution discharges with that. Though the temperature gradient in the foam increases with increased foam expansion ratio. it is not change with increased intensity of heat flux.