• 제목/요약/키워드: Fireball

검색결과 25건 처리시간 0.019초

The optical afterglow of GRB 180205A

  • Paek, Gregory SungHak;Im, Myungshin;Choi, Changsu
    • 천문학회보
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    • 제43권1호
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    • pp.59.1-59.1
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    • 2018
  • On 2018 February 5 a gamma ray burst with trigger time 04:25:29.3 UT was detected by Swift BAT and this event was named GRB 180205A. We observed the optical afterglow of GRB 180205A starting from about 1 hour after the burst until February 22 in the optical bands with the 1m telescope of Deokheung Optical Astronomy Observatory (DOAO), the 1m telescope at Mt. Lemmon Optical Astronomy Observatory(LOAO) and the 0.8m and 0.25m telescopes at McDonald Observatory. According to the fireball model, which is a well-accepted and conventional model for the afterglow of the GRB, the mechanism of the afterglow is that the expanding external blast wave of the GRB successively collides with the ambient medium and loses its energy, and as a result emits radiation at wavelengths longer than gamma rays. Here we present optical photometry and light curve of the afterglow in the R band and analyze it to characterize GRB 180205A.

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3D Terrain Model Application for Explosion Assessment

  • Kim, Hyung-Seok;Chang, Eun-Mi;Kim, In-Won
    • 한국지역지리학회:학술대회
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    • 한국지역지리학회 2009년도 하계학술대회 발표집
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    • pp.108-115
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    • 2009
  • An increase in oil and gas plants caused by development of process industry have brought into the increase in use of flammable and toxic materials in the complex process under high temperature and pressure. There is always possibility of fire and explosion of dangerous chemicals, which exist as raw materials, intermediates, and finished goods whether used or stored in the industrial plants. Since there is the need of efforts on disaster damage reduction or mitigation process, we have been conducting a research to relate explosion model on the background of real 3D terrain model. By predicting the extent of damage caused by recent disasters, we will be able to improve efficiency of recovery and, sure, to take preventive measure and emergency counterplan in response to unprepared disaster. For disaster damage prediction, it is general to conduct quantitative risk assessment, using engineering model for environmentaldescription of the target area. There are different engineering models, according to type of disaster, to be used for industry disaster such as UVCE (Unconfined Vapor Cloud Explosion), BLEVE (Boiling Liquid Evaporation Vapor Explosion), Fireball and so on, among them.we estimate explosion damage through UVCE model which is used in the event of explosion of high frequency and severe damage. When flammable gas in a tank is released to the air, firing it brings about explosion, then we can assess the effect of explosion. As 3D terrain information data is utilized to predict and estimate the extent of damage for each human and material. 3D terrain data with synthetic environment (SEDRIS) gives us more accurate damage prediction for industrial disaster and this research will show appropriate prediction results.

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LPG충전소에서 증기운폭발에 의한 화염의 피해에 관한 연구 (A Study on the Damage of Flame caused by the Vapor Cloud Explosion in LPG Filling Station)

  • 임사환;허용정
    • 한국안전학회지
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    • 제25권3호
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    • pp.53-60
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    • 2010
  • 액화석유가스 자동차는 대도시의 대기환경 개선을 위해 적용되고 있으며 대기 오염물질을 저감시키는데 효과적인 것으로 입증되고 있다. 이와 더불어 환경 친화적인 에너지원으로서 가스의 수요가 날로 급증하고 있으며, LPG 충전소도 해마다 증가추세이다. 따라서 본 논문에서는 충전소에서 증기운폭발에 의한 화염의 영향으로 인간에게 미치는 영향을 알아보고자 한다. 이를 위하여 API에서 규정한 피해예측을 통하여 평가를 실시하였다. 폭발장소에서의 화염에 의해 미치는 영향 거리를 산출하여 거리별 복사열의 크기를 알게 되면 그 지점에서의 피해는 간단하게 예측할 수 있다. 또한 폭발장소 주변에 위치한 인간에게 미치는 영향을 PROBIT 모델에 적용하여 사고피해예측을 평가하였다. 프로빗 분석에 의하면 화염에서 30m 이격된 곳은 1도 화상에 의한 손상확률이 100%, 2도 화상에 의한 손상확률은 99.2%, 화재로 인한 사망확률은 93.4%로 나타났다.

APPLICATION OF 3D TERRAIN MODEL FOR INDUSTRY DISASTER ASSESSMENT

  • Kim, Hyung-Seok;Cho, Hyoung-Ki;Chang, Eun-Mi;Kim, In-Hyun;Kim, In-Won
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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    • pp.3-5
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    • 2008
  • An increase in oil and gas plants caused by development of process industry have brought into the increase in use of flammable and toxic materials in the complex process under high temperature and pressure. There is always possibility of fire and explosion of dangerous chemicals, which exist as raw materials, intermediates, and finished goods whether used or stored in the industrial plants. Since there is the need of efforts on disaster damage reduction or mitigation process, we have been conducting a research to relate explosion model on the background of real 3D terrain model. By predicting the extent of damage caused by recent disasters, we will be able to improve efficiency of recovery and, sure, to take preventive measure and emergency counterplan in response to unprepared disaster. For disaster damage prediction, it is general to conduct quantitative risk assessment, using engineering model for environmental description of the target area. There are different engineering models, according to type of disaster, to be used for industry disaster such as UVCE (Unconfined Vapour Cloud Explosion), BLEVE (Boiling Liquid Evaporation Vapour Explosion), Fireball and so on, among them, we estimate explosion damage through UVCE model which is used in the event of explosion of high frequency and severe damage. When flammable gas in a tank is released to the air, firing it brings about explosion, then we can assess the effect of explosion. As 3D terrain information data is utilized to predict and estimate the extent of damage for each human and material. 3D terrain data with synthetic environment (SEDRIS) gives us more accurate damage prediction for industrial disaster and this research will show appropriate prediction results.

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Intensive Monitoring Survey of Nearby Galaxies (IMSNG) : Constraints on the Progenitor System of a Type Ia Supernova SN 2019ein from Its Early Light Curve

  • 임구;임명신;김도형;백승학;최창수;김소피아;황성용
    • 천문학회보
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    • 제45권1호
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    • pp.36.1-36.1
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    • 2020
  • The progenitor of Type Ia supernovae (SNe Ia) is mainly believed to be a carbon/oxygen white dwarf (WD) with non-degenerate (single degenerate) or another WD companion (double degenerate). However, there is little observational evidence of their progenitor system. Recent studies suggest that shock-breakout cooling emission after the explosion can constrain the size of the progenitor system. To do so, we obtained a optical/Near-IR light curve of SN 2019ein, a normal but slightly sub-luminous type Ia supernova, from the very early phase using our high-cadence observation of Intensive Monitoring Survey of Nearby Galaxies (IMSNG). Assuming the expanding fireball model, the simple power-law fitting of the early part of the light curve gives power indices of 1.91 (B) and 2.09 (R) implying radioactive decay of 56Ni is the dominant energy source. By comparison with the expected light curve of the cooling emission, the early observation provides us an upper limit of the companion size of R∗≤1R⊙. This result suggests that we can exclude a large companion such as red giants, which is consistent with the previous study.

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