• Title/Summary/Keyword: post-fire

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Wildfire-induced Change Detection Using Post-fire VHR Satellite Images and GIS Data (산불 발생 후 VHR 위성영상과 GIS 데이터를 이용한 산불 피해 지역 변화 탐지)

  • Chung, Minkyung;Kim, Yongil
    • Korean Journal of Remote Sensing
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    • v.37 no.5_3
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    • pp.1389-1403
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    • 2021
  • Disaster management using VHR (very high resolution) satellite images supports rapid damage assessment and also offers detailed information of the damages. However, the acquisition of pre-event VHR satellite images is usually limited due to the long revisit time of VHR satellites. The absence of the pre-event data can reduce the accuracy of damage assessment since it is difficult to distinguish the changed region from the unchanged region with only post-event data. To address this limitation, in this study, we conducted the wildfire-induced change detection on national wildfire cases using post-fire VHR satellite images and GIS (Geographic Information System) data. For GIS data, a national land cover map was selected to simulate the pre-fire NIR (near-infrared) images using the spatial information of the pre-fire land cover. Then, the simulated pre-fire NIR images were used to analyze bi-temporal NDVI (Normalized Difference Vegetation Index) correlation for unsupervised change detection. The whole process of change detection was performed on a superpixel basis considering the advantages of superpixels being able to reduce the complexity of the image processing while preserving the details of the VHR images. The proposed method was validated on the 2019 Gangwon wildfire cases and showed a high overall accuracy over 98% and a high F1-score over 0.97 for both study sites.

A Study on the Flame Retardant Performance of MDF Wood According to Flame Retardant Treatment Method (방염처리 방법에 따른 MDF 목재의 방염성능에 관한 연구)

  • Cha, Jung-Min;Hyun, Seong-Ho;Kim, In-Beom;Yoon, Myung-O
    • Fire Science and Engineering
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    • v.25 no.6
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    • pp.146-155
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    • 2011
  • In the study, test was carried out to compare the flame retardant performance for the specimen of MDF wood to which field flame retardant treatment (post processing flame retardant) is applied, which is coated with flame retardant film of 5 companies, locally distributed, and MDF wood (nontreated, flame retardant film non-coated) to which aqueous or oil-based fire-retardant paint is applied. As a result of combustion test of MDF wood which was coated with flame retardant film of 5 companies, 2 products showed suitable values in 4 criteria, but other 3 products showed 10~40 % disqualification rate. In regard of characteristics of fire-retardant paint, oil-based fire-retardant paint is better than aqueous fire-retardant paint in flame retardant performance criteria, but MDF wood to which oilbase fire-retardant paint was applied was shown to have higher toxicity index grade than MDF wood to which aqueous fire-retardant paint was applied relatively.

Post-Fire Damage and Structural Performance Assessment of a Steel-Concrete Composite Bridge Superstructure Using Fluid-Structure Interaction Fire Analysis (FSI 화재해석을 이용한 강합성 교량 상부구조의 화재 후 손상 및 구조성능 평가)

  • Yun, Sung-Hwan;Gil, Heungbae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.41 no.6
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    • pp.627-635
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    • 2021
  • The fire damage and structural performance of a steel-concrete composite superstructure under a highway bridge exposed to fire loading was evaluated. To enhance the accuracy and efficiency of the numerical analysis, a proposed fluid-structure interaction fire analysis method was implemented in Ansys Fluent and Ansys Mechanical. The temperature distribution and performance evaluation of the steel-concrete composite superstructure according to the vertical distance from the fire source to the bottom flange were evaluated using the proposed analysis method. From the analysis, the temperature of the concrete slab and the bottom flange of the steel-concrete composite superstructure exceeded the critical temperature. Also, when the vertical distance from the fire source was 13 m or greater, the fire damage of the steel-concrete composite superstructure was found to within a safe limit.

Modular Building for Urban Disaster Housing: Case Study of Urban Post-Disaster Housing Prototype in New York

  • Ford, George;Ahn, Yong Han;Choi, Don Mook
    • Fire Science and Engineering
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    • v.28 no.6
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    • pp.82-89
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    • 2014
  • Disasters that destroy homes and infrastructure and cause significant financial damage are becoming more common as population centers grow. In addition, several natural disasters have resulted in a major loss of life and created countless refugees due to damage to housing. After major catastrophic disasters, it is very important that the government agencies respond to post-disaster housing issues and provide resources such as temporary housing before the full rehabilitation and reconstruction of destroyed and damaged housing. To provide affordable temporary housing for residents who may lose their homes as the result of a catastrophic disaster including storms, government agencies must develop a post-disaster housing prototype. In general, government agencies should explore several different forms of factory-built single-story, single family housing, such as modular homes, panelized homes, and precut homes. In urban cities including New York and Seoul, it is very important to provide housing which supports the demand for higher-density living spaces than single-family homes or trailers typically available due to the high population density and the desire to resettle as many residents as possible in their former neighborhoods. This study identified the urban post-disaster housing prototypes that may provide higher density housing with high quality living spaces, high air quality, and energy efficiency as well as rapid deployment. A case study of "Urban Post-Disaster Housing Prototype Program in New York" was conducted through a detailed interview process with a designer, engineer, contractor, the Office of Emergency Management (OEM) in New York, the U.S. Army Corps of Engineers (USACE), and temporary occupants. An appropriate disaster housing program that can provide living spaces for victims of disasters that keeps residents in their community and allows them to live and work in their neighborhoods was developed.

Effects of a Forest Therapy Program on Reducing PTSD and Depression and Improving Mood States in Fire Officers

  • Park, Choong-hee;Chun, Juhyeon;Hahm, Yumi;Kang, Deok Ho;Park, Bum-Jin
    • Journal of People, Plants, and Environment
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    • v.24 no.6
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    • pp.693-705
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    • 2021
  • Background and objective: This study was conducted to investigate the effects of forest therapy programs on reducing post-traumatic stress disorder (PTSD), depression and improving mood states in fire officers. Methods: To determine PTSD, depression, and mood states before and after the forest therapy program, the survey results of 185 fire officers were analyzed. Frequency analysis was conducted to identify the demographic characteristics of the participants, and Wilcoxon signed-rank test to analyze the differences among group. Results: As a result of a comparative analysis of PTSD before and after the program, there was a significant decrease in PTSD from 10.65 ± 12.00 to 5.64 ± 8.29 after the program. Depression also showed a statistically significant difference from 3.21 ± 4.00 to 2.21 ± 3.47 after the program. As a result of comparatively analyzing mood states before and after the program, there was an increase in positive factors and a decrease in negative factors. Total mood disturbance (TMD) also showed a statistically significant decrease from 5.78 ± 17.37 to -7.38 ± 10.35 after the program. Conclusion: This study has significance in verifying that forest therapy programs can bring psychological changes to fire officers, and these results can be used as a basis for stress management and relief of fire officers.

Operation Room Fire: Caution for Using Electrocautery after Rinsing Operation Field at the End of the Surgery with Alcohol-Based Cleansing Solutions (수술방 화재: 수술 종료 시 알코올 함유 피부 소독액을 이용한 수술부위 세척 이후 전기소작기 사용 주의)

  • Song, Jong Keun;Shin, Hyojeong;Lee, Jun Yong
    • Journal of the Korean Burn Society
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    • v.22 no.2
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    • pp.34-37
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    • 2019
  • Fires in operating rooms rarely occur. However, this type of disaster can complicate almost any surgical procedure. Fuel, heat and oxygen are related with fire outbreak. When ignition sources such as alcohol-based surgical preparation solutions are present, the risk of an operating room fire increases, and burns are more severe in such conditions. Many manufacturers recommend waiting at least three minutes after application to allow complete drying for reduce fire risk. There are a few studies regarding flame burns in the operation room, although most of these studies are related to preoperative skin preparation. However, alcohol containing solutions can be used occasionally for cleansing of the operation field after the surgery, therefore, the surgical team should pay attention to surgical fires, even if they have completed the operation successfully. We present our case of a post-operative flame burn and introduce some precautions that will reduce the risk of alcohol burns.

Survival and Goodness in a Post - apocalyptic Future: Cormac McCarthy's The Road (포스트 - 묵시록 미래의 생존과 선의 실행: 코맥 매카시의 『로드』)

  • Sung, Junghye
    • English & American cultural studies
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    • v.16 no.2
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    • pp.71-88
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    • 2016
  • Cormac McCarthy's The Road depicts a post-apocalyptic future in which the time and reason of catastrophe are not specified, but it can be seen to project the contemporary social and ethical concerns in the dismal setting. In this respect, the journey the man and boy depart for to the South is on one hand a journey to seek a warmer place to support their lives in the literal sense and, on the other hand, a journey to seek 'what a human being is' in the devastated world in a metaphorical sense since they face extremely harsh and tremendously poignant conditions in which their creed as human beings is tested. This paper aims to explore the hazards of the current society that the text criticizes and the morality and ethical values to be preserved and pursued. The second chapter examines how the text describes the contemporary crisis through the dark and coldness of the land and its sterility. The land produces almost nothing as the entire surface was scorched and is now covered with thick ashes. It shows perfectly a destroyed and irrecoverably frozen land. Throughout this desolate and ruined land, the atrocity and violence of the survivors goes beyond the limit. Ravaging strangers and plundering villages are widely spread. These conditions mirror the apparent selfishness and immorality of the recent society. The third chapter analyzes the man's inconsistent or dualistic narrative on the good. He knows what the good is but doesn't allow the boy to demonstrate the good behavior on others. His conflict is rooted in his hope to protect his son from being attacked by others. Therefore it can be interpreted that the meaning and orders of living in this post-apocalyptic period are uncertain and indecisive. The fourth chapter examines the belief the man and the boy clings to. Unlike the man's contradictory decisions, he shows definite firmness to be 'the good' by not eating people and carrying 'the fire.' Until he dies, the man endeavors to protect his son and have him acquire the moral conviction and strength to carry the fire in the world. In conclusion, the text reads the current society critically and highlights the importance of the humanity that must not be discarded throughout the generations.

Development predictive equations for tensile properties of S235JR structural steels after fire

  • Ozer Zeybek;Veysel Polat;Yasin Onuralp Ozkilic
    • Steel and Composite Structures
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    • v.53 no.2
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    • pp.243-252
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    • 2024
  • Conventional carbon mild steel is a type of steel known for its low carbon content and generally used in the construction industry. Its easily formable and weldable properties make this steel a widely preferred material for buildings, bridges and various construction projects. Other advantages of these steels are their low cost and good mechanical properties. However, high temperatures have an impact on the microstructure and mechanical characteristics of these materials. When high temperatures are present during a fire, steels show significant microstructural changes. Elevated temperatures often decrease the mechanical characteristics of steels. For this purpose, evaluating the post-fire behavior of conventional structural mild steel is an important issue in terms of safety. A combined experimental and parametric study was conducted to estimate fire damage to steel buildings, which is an important issue in the construction field. Tensile test coupons were cut from conventional structural S235JR mild steel sheets with thicknesses ranging from 6 mm to 12 mm. These samples were exposed to temperatures as high as 1200 ℃. After heat treatment, the specimens were allowed to naturally cool to ambient temperature using air cooling before being tested. A tensile test was performed on these coupons to evaluate their mechanical properties after fire, such as their elastic modulus, yield strength, and ultimate tensile strength. The mechanical behavior of conventional S235JR structural steel changed significantly when the heating temperature reached 600℃. The thickness of the steel had a negligible effect on yield strength loss, with the highest measured loss being 50% for 8 mm thickness at 1200℃. For thinner sections (6 mm), yield strength decreased by up to 40%, while thicker samples (12 mm) showed similar reductions. Ultimate tensile strength also showed minimal changes up to 600℃, but beyond this point, a notable decline occurred, with approximately 30% strength loss at 1200℃. The modulus of elasticity remained almost constant up to 800℃, but at 1200℃, the loss reached around 20% for thicker sections (10 mm and 12 mm) and up to 35% for thinner sections (6 mm and 8 mm). Overall, high temperatures led to significant deterioration in both yield and ultimate strength, with a general loss of load-bearing capacity above 600℃. A new equation was formulated from experimental results to predict changes in the mechanical properties of S235JR steels. This equation offers a precise evaluation of buildings made from conventional structural S235JR mild steel after fire exposure. Furthermore, the empirical equation is applicable to low-strength steels with yield strengths ranging from 235 MPa to 420 MPa.

Forest Fire Damage Analysis Using Satellite Images (위성영상을 이용한 산불재해 분석)

  • Kang, Joon-Mook;Zhang, Chuan;Park, Joon-Kyu;Kim, Min-Gyu
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.28 no.1
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    • pp.21-28
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    • 2010
  • Forest fire is one of the main factor disturbing the environment of forest, and it influences greatly the structure and function on forest. The process of vegetation recovery could be decided according to the extent of the damage. It is required a lot of man powers and budgets to understand born severity and process of vegetation rehabilitation at the damaged area after large-fire. However, the analysis of born severity in the forest area using satellite imagery can acquire rapidly information and more objective results remotely in the large-fire area. In this study, the space sensors have been used to map area burned, assess characteristics of active fires. For classifying fire damaged area and analyzing severity of Cheongyang-Yesan fire in 2002, in this paper we use pre- and post-fire imagery from the Landsat TM and ETM+ to compute the evaluate large-scale patterns of burn severity, use the digital stock map to calculate the damaged condition about the forest fires damaged regions and use the NDVI to monitoring the situation of the revegetation.

Numerical Simulation on Disproportionate Collapse of the Tall Glulam Building under Fire Conditions

  • Zhao, Xuan;Zhang, Binsheng;Kilpatrick, Tony;Sanderson, Iain
    • International Journal of High-Rise Buildings
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    • v.10 no.4
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    • pp.311-321
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    • 2021
  • Perception of the public to structural fires is very important because there are only a number of tall timber buildings constructed in the world. People are hesitating to accept tall timber buildings, so it is essential to ensure the first generation of tall timber buildings to a very high standard, especially fire safety. Right now, there are no specific design standards or regulations for fire design of tall timber buildings in Europe. Even though heavy timber members have better fire resistance than steel components, many conditions still need to be verified before considering the use of timber materials, e.g. fire spread, post-fire collapse, etc. This research numerically explores the structural behaviours of a tall Glulam building when one of its internal Glulam (Glued laminated timber) columns fails after sustaining a full 120-min standard fire and is removed from the established finite element building model created in SAP2000. The numerical results demonstrate that the failure and removal of the selected internal Glulam column may lead to the local failure of the adjacent CLT (Cross laminated timber) floor slabs, but will not lead to large disproportionate damage and collapse of the whole building. Here, the building is assumed to be located in Glasgow, Scotland, UK.