• 제목/요약/키워드: fire growth

검색결과 351건 처리시간 0.028초

건축 내장재의 Flashover시간 및 열방출량 예측에 관한 연구 (A Study on the Prediction of Flashover Time and Heat Release Rate(HRR) for Building Interior Materials)

  • 하동명
    • 한국화재소방학회논문지
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    • 제18권3호
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    • pp.30-38
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    • 2004
  • 화재성장기 동안의 중요한 특징은 국부연소에서 전실연소로 전이되는 플래시오버 현상이다. 본 연구의 목적은 건축내장재의 플래시오버 시간 및 발화시간 그리고 열방출량을 예측에 있다. Response Surface Methodology(RSM) 방법과 문헌자료를 사용하여 플래시오버 시간 및 발화시간 그리고 열방출량을 예측하는 식을 제시하였다. 예측식에 의해 계산된 플래시오버 시간과 문헌값의 A.A.P.E.는 38.74초, A.A.D.는 51.42초 그리고 상관계수는 0.975이다. 발화시간의 예측값과 문헌값의 A.A.P.E.는 10.96초, A.A.D.는 1.97초 그리고 상관계수는 0.962이다. 또한 시간에 의한 플래시오버 열방출량의 예측값과 문헌값의 A.A.P.E.는 29.92, A.A.D.는 514 그리고 상관계수는 0.830이다. 제시한 예측식에 의한 계산값은 문헌값과 일치하였다. 따라서 본 연구에서 제시된 식이 다른 건축내장재 연구에도 이용되기를 기대한다.

평면형 구리 - 탄소 전극의 형태별 재기전압 특성 및 파형 패턴에 관한 연구 (Study on Restriking Transient Voltage Characteristics and Waveform Patterns of Planar Copper-Carbon Electrodes using Forms)

  • 임종민;최충석
    • 한국화재소방학회논문지
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    • 제34권4호
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    • pp.1-6
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    • 2020
  • 본 논문은 직렬 아크 방전이 진행될 때의 전압 및 전류 파형을 실시간 측정하였다. 아크 방전의 방사 패턴을 분석한 결과 간헐적인 방전, 아크의 성장, 발열부의 생성, 플룸의 발생, 적열부 형성 순서로 진행되는 것을 알 수 있었다. 직렬 아크 방진이 진행될 때 전류 및 전압 파형은 정현파와 같은 주기성을 나타냈다. 그리고 + 파형에서 - 파형으로 바뀔 때와 - 파형에서 + 파형으로 바뀔 때 파형의 재기전압이 발생하는 것이 확인되었다. 방전이 진행될 때 1 s 동안에 발생하는 열량은 약 0.317 mJ이고, 600 s 동안에 약 190 mJ의 열이 발생하는 것으로 해석되었다. 그리고 단락 지속시간은 약 1.66 ms인 것으로 해석되었으며, 동일한 주기에서 전압 파형은 49.9 V까지 전위가 상승하는 것을 알 수 있었다. 또한, 방전이 진행될 때 전류의 실효치는 약 1.72 A이고, 최대치는 약 2.53 A로 분석되었다. 그리고 전압의 실효치는 약 42.8 V로 계산되었고, 최대치는 약 208 V로 측정되었다.

낙엽송(落葉松)(Larix leptolepis Gorden)의 심부재(心腐材) (On the Pith-damaged Wood of Larix leptolepis Gorden)

  • 민두식;이세표;최태호
    • 한국산림과학회지
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    • 제79권4호
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    • pp.419-423
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    • 1990
  • 낙엽송의 심부후재(心腐朽材) 형성 원인과 성장상태(成長狀態) 및 그의 조성분(組成分) 차이를 구명하기 위한 실험이다. 1. 낙엽송이 정상적인 생장을 한 10년생 까지는 그의 성장율이 32.4% 이었으나 심부피해가 있는 11-13년 사이는 19.4%로 13% 점감하고 있다. 그리고 심부후재 형성은 산화(山火)에 의한 수피(樹皮)의 화상부분(火傷部分)부터 이루어지고 있다. 낙엽송 임지(林地)의 산화피해로 생기는 심부후재로 인한 재적(材積) 손실(損失)은 약 20% 이상이 되고 있다. 2. 조성분에 있어 탄분(炭分) 함유량은 심재가 0.05%, 심부후재부가 0.08%로 변재 0.29%에 비하여 적은데 이러한 원인은 유출성분(抽出成分) 함량 차이에서 오는 것으로 볼 수 있다. Holocellulose 함유량은 54.3%에서 59.3%로 심재, 심부후재부 그리고 변재 사이에 차이가 인정되지 않는다. Pentosan 함유량은 심재 6.3% 및 심부후재부가 6.6%로 변재보다 많았다. Lignin 함유량은 심재 34.4% 보다 심부후재부에서 감소되고 있는데 이러한 현상은 목재의 제강도(諸强度)가 열화(劣化)된다고 본다.

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The Great Western Woodlands TERN SuperSite: ecosystem monitoring infrastructure and key science learnings

  • Suzanne M Prober;Georg Wiehl;Carl R Gosper;Leslie Schultz;Helen Langley;Craig Macfarlane
    • Journal of Ecology and Environment
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    • 제47권4호
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    • pp.272-281
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    • 2023
  • Ecosystem observatories are burgeoning globally in an endeavour to detect national and global scale trends in the state of biodiversity and ecosystems in an era of rapid environmental change. In this paper we highlight the additional importance of regional scale outcomes of such infrastructure, through an introduction to the Great Western Woodlands TERN (Terrestrial Ecosystem Research Network) SuperSite, and key findings from three gradient plot networks that are part of this infrastructure. The SuperSite was established in 2012 in the 160,000 km2 Great Western Woodlands region, in a collaboration involving 12 organisations. This region is globally significant for its largely intact, diverse landscapes, including the world's largest Mediterranean-climate woodlands and highly diverse sandplain shrublands. The dominant woodland eucalypts are fire-sensitive, requiring hundreds of years to regrow after fire. Old-growth woodlands are highly valued by Indigenous and non-Indigenous communities, and managing impacts of climate change and the increasing extent of intense fires are key regional management challenges. Like other TERN SuperSites, the Great Western Woodlands TERN SuperSite includes a core eddy-covariance flux tower measuring exchanges of carbon, water and energy between the vegetation and atmosphere, along with additional environmental and biodiversity monitoring around the tower. The broader SuperSite incorporates three gradient plot networks. Two of these represent aridity gradients, in sandplains and woodlands, informing regional climate adaptation and biodiversity management by characterising biodiversity turnover along spatial climate gradients and acting as sentinels for ecosystem change over time. For example, the sandplains transect has demonstrated extremely high spatial turnover rates in plant species, that challenge traditional approaches to biodiversity conservation. The third gradient plot network represents a 400-year fire-age gradient in Eucalyptus salubris woodlands. It has enabled characterisation of post-fire recovery of vegetation, birds and invertebrates over multi-century timeframes, and provided tools that are directly informing management to reduce stand-replacing fires in eucalypt woodlands. By building regional partnerships and applying globally or nationally consistent methodologies to regional scale questions, ecological observatories have the power not only to detect national and global scale trends in biodiversity and ecosystems, but to directly inform environmental decisions that are critical at regional scales.

Comparison of Growth Performance of Antibiotic-free Yorkshire Crossbreds Sired by Berkshire, Large Black, and Tamworth Breeds Raised in Hoop Structures

  • Whitley, N.;Morrow, W.E.M.;See, M.T.;Oh, S.H.
    • Asian-Australasian Journal of Animal Sciences
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    • 제25권10호
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    • pp.1351-1356
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    • 2012
  • The objective of this study was to compare body weight, ADG, and feed:gain ratio of antibiotic-free pigs from Yorkshire dams and sired by Yorkshire (YY), Berkshire (BY), Large Black (LBY) or Tamworth (TY) boars. All the crossbred pigs in each of three trials were raised as one group from weaning to finishing in the same deep-bedded hoop, providing a comfortable environment for the animals which allowed rooting and other natural behaviors. Birth, weaning and litter weights were measured and recorded. From approximately 50 kg to market weight (125 kg), feed intake and body weights were recorded manually (body weight) or using a FIRE (Feed Intake Recording Equipment, Osborne Industries Inc. Osborne, Kansas) system with eight individual feeding stations. Feed intake data for 106 finishing pigs between 140 and 210 d of age and the resulting weights and feed conversion ratios were analyzed by breed type. Least square means for body weights (birth, weaning and to 240 d) were estimated with Proc Mixed in SAS 9.2 for fixed effects such as crossbreed and days of age within the sire breed. The differences within fixed effects were compared using least significant differences with DIFF option. Individual birth weights and weaning weights were influenced by sire breed (p<0.05). For birth weight, BY pigs were the lightest, TY and YY pigs were the heaviest but similar to each other and LBY pigs were intermediate. For weaning weights, BY and LBY pigs were heavier than TY and YY pigs. However, litter birth and weaning weights were not influenced by sire breed, and average daily gain was also not significantly different among breed types. Tamworth sired pigs had lower overall body weight gain, and feed conversion was lower in TY and YY groups than BY and LBY groups (p<0.05), however, number of observations was somewhat limited for feed conversion and for Tamworth pigs. Overall, no convincing differences among breed types were noted for this study, but growth performance in the outdoor environment was satisfactory.

지리산(智異山) 제석봉(帝釋峰) 산화적지(山火跡地)의 식생회복(植生回復) 및 관리방안(管理方案) (Vegetation Rehabilitation and Management Strategy of the fired Woodland in Chesuk-bong of Mt. Chiri)

  • 정재민;문현식;마호섭
    • 한국환경복원기술학회지
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    • 제2권1호
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    • pp.58-65
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    • 1999
  • The purpose of this study was to evaluate the effect of rehabilitation measures on the fired woodland of Chesuk-bong in Mt. Chiri through the vegetation structure and comparison of growth pattern between natural seedlings and transplanted Abies koreana seedlings. It was also discussed the rate of standing and fallen trees of dead conifers in the management strategy for vegetation regeneration and protection of sub-alpine area. In this fired woodland, shrub layers consisting of Weigela subsessilis, Sambucus williamsii var. coreana, Rhododendron schlippenbachii, R. mucronulatum, Tripterygium regelii, and etc. were gradually expanded, and tree species such as Betula ermani, Sorbus commixta, Acer pseudosieboldianum, and Malus baccata var. mandshurica were also regenerated. The growth of height and crown width of Abies koreana seedlings transplanted for vegetation regeneration were a little lower than those of natural seedlings. The seedlings of A. koreana transplanted in this fired woodland grew about 50.6% normally, but the others had multi-branched or growth stopped by death of terminal shoot. Because the number of dead conifers by fire tend to be gradually increased as time passed, it can occurs to the soil erosion and landslide by weakness of the cohesion and resistance of soil. Therefore, it is consider that rehabilitation measures projects of the fired woodland in subalpine area may be more prevention a natural disaster like soil erosion, flood and landslide.

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최근 우리나라 e-Learning 시장의 주요 동향 및 향후 전망 (Some Problems of e-Learning Market in Korea)

  • 윤영한
    • 통상정보연구
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    • 제9권2호
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    • pp.103-120
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    • 2007
  • The knowledge based economy requires more and more people to learn new knowledge and skills in a timely and effective manner. These needs and new technology such as computer and Internet are fueling a transition in e-learning. According to specialist's opinion, imagination experience studying is generalized, and learning environment that language barrier by studying, multi-language studying Machine that experience past things that disappear through simulation, and travel area, and experience future changed state disappears is forecasting to come. This is previewing finally that it may become future education that education and IT, element of entertainment is combined. Already, became story that argument for party satellite of e-Learning existence passes one season already. e-Learning is utilized already in all educations that we touch by effectiveness by corporation's competitive power improvement and implement of lifelong education in educational institutions through present e-Learning. It is obvious that when see from our viewpoint which is defining e-Learning by one industry and rear by application to education as well as one new growth power about these, e-Learning industry becomes very important means that can solve dilemma of growth real form. Only, special quality of digital industry that e-Learning is being same with other digital industry and repeat putting out a fire rapidly, and is repeating sudden change that these evolution is not gradual growth of accumulation and improvement of technology that is appearing consider need to. In the meantime, we need to observe about evolution of Information Technology. Because there is some scholars who e-Learning's concept foresees to evolve by u-Learning.(although, a person who see that these concept is not more in marketing terminology by some scholars' opinion is). This u-Learning's concept means e-Learning that take advantage of ubiquitous technology as Ubiquitous-Learning's curtailment speech. Ubiquitous, user means Information-Communication surrounding that can connect to network freely regardless of place without feeling network or computer. There is controversy about introduction time regarding these direction, but e-Learning is judged to evolve by u-Learning necessarily. Because keep in step and age that study all contents that learner wants under environment of 3A (any time, any whrer, any device) by individual order thoroughly is foreseen to come in ubiquitous learning environment that approach more festinately.

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다구찌 방법을 이용한 석재표면처리장치의 최적표면가공조건 선정에 관한 연구 (The Optimal Parameter Design of the stone surface equipment Using the Taguchi Method)

  • 김득주;서장훈;박명규
    • 대한안전경영과학회지
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    • 제6권2호
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    • pp.251-262
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    • 2004
  • There is boner process of stone manufacturing to become quality down of stone to consolidated micro crack appearance of stone surface and biotite by fire that is to be route process in stone surface by flame of LPG. And then, it is develop that stone surface process equipment by automation for the work method of boner process can be substitute work method by shotball blasting. To developement of equipment, There is to be down noise and dust. Acording to remove calamity growth hazardous substance in the work environment, there is to solve workplace avoidance factor. We have taken Taguchi's parameter design approch, specifically orthogonal array, and determined the optimal levels of stone surface through analysis of the experimental results using SIN ratio.

지하구조물내 전기재해 방지를 위한 설치지침 및 예방시스템 구축 (Recommended Practice on the Precautinary System and Installation to prevent electrical fire from reoccurring in underground tunnel)

  • 김세동;김영진;강재모
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 2005년도 춘계학술대회논문집
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    • pp.337-341
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    • 2005
  • Most utiltity systems are subject to frequent changes, often due to increased loads and demand to up-grade quality of service provided. Urban renewal, expressway construction and suburban growth have also caused significant changes in urban utility distribution systems. Recently, it is required that a guideline for planning of a complete system, the reasonable design and construction methods for the efficient installation common utility tunnels must be estabilished. It prompts drastic measures to guard cities and their inhabitants against the horror of massive fires in the future. Preparedness holds the key to safety.

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서비스 산업의 품질향상을 위한 6시그마 방법 적용 (On the Application of 6 Sigma Method for Quality Improvement of Service Industry)

  • 이강인;이순산
    • 산업경영시스템학회지
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    • 제31권3호
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    • pp.35-42
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    • 2008
  • In the national economy, rate of service industry is going up to compare with manufacture industry. In spite of getting lots of results to be introduced 6 sigma methodology in Korea, many service companies is suffering with trial and errors. Also 6 sigma isn't settled perfect yet. The reason for that, 6 sigma have been applied to various service without considering. Therefore, this research shows to you right practice plans for service industrial classification to check structural features and difference. So this research seeks methods for revitalization of 6 sigma methodology in service industry after checking existed research, case study for companies to be applied by 6 sigma. As the result, service industry is forecasted to contribute greatly in economic growth and employment enlargement through enlargement of service role in manufacturing industry production as well as by itself.