• Title/Summary/Keyword: heat-damage

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Prevention of Early Frost Damage of the Concrete under Severely Low Temperature according to Heat Curingmethods (극저온 조건에서 보온양생 방법 변화에 따른 콘크리트의 초기동해 방지)

  • Han, min-Cheol
    • Journal of the Korea Institute of Building Construction
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    • v.16 no.1
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    • pp.67-76
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    • 2016
  • Concrete exposed to severely low temperature below $-20^{\circ}C$ should be provided with proper heat supplying curing to protect the concrete from early frost damage at the time of pouring.meanwhile, so far, effective heat curingmethods of the concrete under severely low temperature are not well established in Korea. For this reason, the objective of this paper is to provide effective heat curingmethod of concrete exposed to severely low temperature to protect early frost damage by varying the combination of heat curingmaterial combinations. Temperature history,maturity development and core strength results are investigated. Fourmock-up specimens simulating slab, wall and column were prepared and heat insulation, heat supplying and both were applied. Test results indicate that the combination of quadruple layer bubble sheet(4BS) and embedding of heating cable has desirable performance for a slab, and heat supplying curing inside heat enclosure and heat generationmat also shows desirable performance for a wall, and for a column, use of EPS heat insulation has proper performance against early frost damage, which reaches $45^{\circ}D{\cdot}D$ and helps the concretemaintain above $0^{\circ}C$ within 3 days. Themethodsmentioned above are believed to be optimum protection from early frost damage of the concrete under $-20^{\circ}C$.

Analysis of regional type according to spatial correspondence between heat wave vulnerable areas and health damage occurrence (폭염 취약지역과 건강 피해 발생의 공간적 일치성에 따른 지역 유형 분석)

  • Hee-Soo HWANG;Ji Yoon CHOI;Jung Eun KANG
    • Journal of the Korean Association of Geographic Information Studies
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    • v.26 no.1
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    • pp.89-113
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    • 2023
  • This study aimed to identify heat wave vulnerable areas and discuss spatial typology and policy directions through spatial coincidence analysis of heat wave damage. By utilizing the climate change vulnerability assessment of the Intergovernmental Panel on Climate Change (IPCC) and Spatial Statistics Comparison Analysis, this study examined cities, counties, and districts in South Korea for five years (2015-2019), including 2018, when the heat wave was most extreme. It was determined that the number of heat wave days (exposure) was the most impactful among various factors for heat wave vulnerability. Sensitivity and adaptive capacity to heat waves were found to vary according to regional characteristics. The relationship between heat wave vulnerability and damage was categorized into four types through spatial coherence. Hot to Hot and Cold to Cold types have a positive relationship between vulnerability and damage, while Hot to Cold and Cold to Hot types have a negative relationship. The findings suggest that since different types of regions have distinct characteristics and conditions, policies and research for improvement should be directed to address each region separately. This study may be used as basic data for establishing heat-related policies in the future, as it categorizes regions by considering both heat vulnerability and damage and examines the direction of response by type.

A Study on the Correlation between the Cold-damage Six-meridian disease of Qibo (岐伯六經病證) and the Sasang Constitutional Symptomatology (四象體質病證) (기백육경병증(岐伯六經病證)과 사상체질병증(四象體質病證)간의 상관관계 연구)

  • Lee, Jun-Hee
    • Journal of Sasang Constitutional Medicine
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    • v.33 no.1
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    • pp.1-21
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    • 2021
  • Objective The purpose of this study was to examine the correlation between the Cold-damage Six-meridian disease of Qibo (岐伯六經病證) and Sasang Constitutional Symptomatology (四象體質病證), presented in Discourse on the Origin of Eastern Medicine (醫源論) of Longevity and Life Preservation in Eastern Medicine (Donguisusebowon, 東醫壽世保元). Method The process of development from Cold-damage Six-meridian disease of Qibo (岐伯六經病證) to Six Meridians Physical Symptoms and Medicines (六經形證用藥) in the chapter Cold(寒門) of the Treasure Mirror of Eastern Medicine (Donguibogam, 東醫寶鑑) was investigated. And the correlation between Six Meridians Physical Symptoms and Medicines (六經形證用藥) and Sasang Constitutional Symptomatology (四象體質病證) was considered. Results and Conclusions 1. The Cold-damage Six-meridian disease of Qibo (岐伯六經病證) in the chapter Heat Treatise (熱論篇) of Basic Questions (素問) had evolved into Six Meridians Physical Symptoms and Medicines (六經形證用藥) in the chapter Cold(寒門) of the Treasure Mirror of Eastern Medicine (Donguibogam, 東醫寶鑑) through Book for Life Saving (Huorenshu, 活人書), a work of Zhu Gong (朱肱), Six Books on Cold Damage disease (Shanghanliushu, 傷寒六書), a work of Tao Hua (陶華) and Introduction to Medicine (YixueRumen, 醫學入門), a work of Li Chan (李梴). 2. The correlation between the Cold-damage Six-meridian disease of Qibo (岐伯六經病證) and Sasang Constitutional Symptomatology (四象體質病證) can be analyzed and understood through Six Meridians Physical Symptoms and Medicines (六經形證用藥) in the chapter Cold(寒門) of the Treasure Mirror of Eastern Medicine (Donguibogam, 東醫寶鑑). 3. Greater Yang meridian disease of Qibo (岐伯) is related to Soyangin early stage of Lesser-Yang Wind-Injury symptomatology and Soyangin early stage of Chest-Heat symptomatology, Yang Brightness meridian disease and Greater Yin meridian disease to Taeeumin Liver-Heat symptomatology, Lesser Yin meridian disease to Soyangin Chest-Heat symptomatology, Lesser Yang meridian disease to Soyangin early stage of Lesser-Yang Wind-Injury symptomatology and Reverting Yin meridian disease to Soeumin Reverting Yin symptomatology of Greater Yang disease.

Text Mining and Network Analysis of News Articles for Deriving Socio-Economic Damage Types of Heat Wave Events in Korea: 2012~2016 Cases (뉴스 기사 텍스트 마이닝과 네트워크 분석을 통한 폭염의 사회·경제적 영향 유형 도출: 2012~2016년 사례)

  • Jung, Jae In;Lee, Kyoungjun;Kim, Seungbum
    • Atmosphere
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    • v.30 no.3
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    • pp.237-248
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    • 2020
  • In order to effectively prepare for damage caused by weather events, it is important to proactively identify the possible impacts of weather phenomena on the domestic society and economy. Text mining and Network analysis are used in this paper to build a database of damage types and levels caused by heat wave. We collect news articles about heat wave from the SBS news website and determine the primary and secondary effects of that through network analysis. In addition to that, based on the frequency with which each impact keyword is mentioned, we estimate how much influence each factor has. As a result, the types of impacts caused by heat wave are efficiently derived. Among these types of impacts, we find that people in South Korea are mainly interested in algae and heat-related illness. Since this technique of analysis can be applied not only to news articles but also to social media contents, such as Twitter and Facebook, it is expected to be used as a useful tool for building weather impact databases.

The Study of Experiment on Preventing Frost Damage at Early Age of Mortar in Low Temperature using Reduction Slag. (환원슬래그를 사용한 모르타르의 저온에서의 초기동해 방지에 관한 연구)

  • Kim, Hyeong-Cheol;Choi, Hyun-Kuk;Min, Tae-Beom
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.05a
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    • pp.203-204
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    • 2016
  • In this research, it used cement power and reduction slag, which generates high hydration heat in hydration reation without heat cure below -5℃ degree. Purpose of final research is preventing freezing and thawing by making the compressive strength 5MPa in 3days below zero temperature due to own heat of concrete. and it is the result of physical characteristic and thermal property evaluation of reduction slag. Because reduction sag generates high hydration heat, compressive strength development is excellent. By generating highly Hydration heat by C12A7 and C3A in reduction slag, compressive strength is developed in low temperature. In case of displacing only reduction slag without SO3, it is indicated that quick-setting occurs by shortage of SO3. For preventing quick-setting, gypsum is used essentially. According to this research result, in case of using reduction slag and gypsum as a ternary system, Compressive strength developed 5MPa in 3days below zero temperature. It is identified to prevent early frost damage of concrete below zero temperature.

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A Study on the Brake Frictional Heat between Wheel Tread and Brake Shoe of E.M.U.'s (도시철도 차량의 차륜답면과 제륜자간 제동 마찰열에 관한 연구)

  • Kim, Seong-Keol;Yoon, Cheon-Joo;Goo, Byeong-Choon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.6
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    • pp.95-103
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    • 2006
  • Wheel treads of E.M.U. are usually under a heavy thermal load by brake frictional heat between wheel and brake shoe and damaged by repeated thermal and mechanical loads. To examine the cause of wheel tread damage of E.M.U.'s in service running, a systematic approach has been used. This study is composed of three parts. Frictional heat analysis was conducted in the first part by finite element method. Two kinds of brake shoes in service were considered. In the second part, experimental study was carried out on a brake dynamometer. Temperatures were measured for the two brake shoes. And experimental study in service running E.M.U.'s was performed. Wheel and brake shoe temperatures were measured by using thermocouples and temperature indicating strips. Finally metallurgical characteristics were examined by a SEM/EDS and the cause of the wheel damage was analyzed. It seems that aggregated ferrous component is a main cause of the wheel tread damage.

Protective Role of Light in Heat-Induced Inhibition of Photosynthesis in Isolated Chloroplasts

  • Jun, Sung-Soo;Kim, Chang-Hoon;Hong, Young-Nam
    • Journal of Photoscience
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    • v.5 no.4
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    • pp.157-162
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    • 1998
  • The effect of heat treatment in the light on the subsequent CO2 fixation was studied with isolated spinach chloroplasts to define the role of light during heat stress. The degree of inhibition in CO2 fixation after heat treatment at 35$^{\circ}C$ under full light intensity (600W/$m^2$) was same as that in the dark. However, heat treatment of isolated chloroplasts in the light manifested thylakoidal damage, which did not occur in the dark. Under weak light (10~30 W/$m^2$ ) where no thylakoidal damage occurred, the inhibition was substantially alleviated , showing protective effect of light . The inhibition caused by heat treatment in the dark or light is prevented by the addition of a few combined compounds to the medium prior to treatment. Fructose-1-6- bisphosphate(with aldolase)and ribose-5-phosphate, known to be effective combined with oxaloacetate in preventing inhibition after heat treatment in the dark were equally effective in the light even without oxaloacetate. Addition of sugar phosphate reduced the Mehler reaction, which may occur in fast rae under high light. However, the addition of bicarbnate and catalase that would remove Mehler reaction did not provide any protection, indicating that protective role of sugar phosphate is elsewhere. Furghermore, in whole plants rapid recovery from heat stress was observed in the light. The apparently lesser or equal inhibition in spite of additional thylakoidal damage under heat stres in the light and less requirement for the protection against heat treatment suggest that the inhibitory effect of heat stress is alleviated by light treatment.

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Korean Red Ginseng (Panax ginseng Meyer) with enriched Rg3 ameliorates chronic intermittent heat stress-induced testicular damage in rats via multifunctional approach

  • Kopalli, Spandana Rajendra;Cha, Kyu-Min;Hwang, Seock-Yeon;Jeong, Min-Sik;Kim, Si-Kwan
    • Journal of Ginseng Research
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    • v.43 no.1
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    • pp.135-142
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    • 2019
  • Background: Panax ginseng Meyer, known as Korean Red Ginseng (KRG), is one of the important age-old traditional herbs used in boosting libido and improving male fertility. In this study, the effects of Rg3-enriched KRG extract (KGC04P) on heat stress-induced testicular damage in experimental rats was evaluated. Methods: Male rats (Sprague-Dawley) were divided into four groups (n = 10): normal control (NC), heat-stressed control (HC), heat-stressed plus KGC04P-100 mg/kg (HK100), and heat-stressed plus KGC04P-200 mg/kg (HK200) groups. Starting 1 week prior to heat stress, animals were administered orally with KGC04P (100 and 200 mg/kg) mixed with a regular pellet diet and continued for 25 weeks. Heat stress was induced to HC, HK100, and HK200 groups by intermittently exposing the animals to high temperatures ($32{\pm}1^{\circ}C$, 2 h/day). After 6 months, animals were euthanized under general anesthesia with carbon dioxide and evaluated for various parameters in serum and testicular tissue by using Western blotting, biochemical kits, and reverse transcription-polymerase chain reaction. Results: Significant (p < 0.05) alterations in several parameters, such as body/organ weight, sperm kinematics, and lipid metabolism marker levels, in the serum and testis of rats were observed. Further, the expression of testicular antioxidant enzymes, inflammatory cytokines, sex hormonal receptors, and spermatogenesis-related genes were also affected significantly (p < 0.05) in the heat-stressed group. However, KGC04P prevented the heat stress-induced changes in rats significantly (p < 0.05) at both concentrations. Conclusion: KGC04P attenuated heat stress-induced testicular damage by a multifunctional approach and can be developed as an excellent therapeutic agent for hyperthermia-mediated male infertility.

A Study of Effects of Heated Rods on Formation of Perm Waves and Hair Bleach (모발의 퍼머넌트 웨이브 형성 및 탈색에 미치는 열 함유 로드의 영향)

  • Jeon, Hyun Jin;Chung, Chan Yi;Lim, Sun Nye
    • Textile Coloration and Finishing
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    • v.26 no.1
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    • pp.63-70
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    • 2014
  • This study has attempted to figure out the effects of the surface heat of perm rods on hair. For this, after forming perm waves, hair damage and its causes have been investigated with a different hair bleach method. If hair was bleached immediately without shampooing after a perm using the heat of rods, great perm waves were formed. However, severe damage was found on the hair because of the heated rods. In addition, when hair was shampooed and dried after the perm, hair bleach was more effective. It has been confirmed that hair was damaged because of high temperature of the surface of the rods. In fact, the heated rods had a direct effect on hair damage. According to these results, it has been confirmed that heat-based perms can accelerate hair damage. Therefore, it is necessary to perform a study on the minimization of the heating of permanent tools.

A Study on Damge Effect from Boiling Liquid Expanding Vapor Explosion(BLEVE) of LPG Charging Facility (LPG 충전소의 BLEVE 현상에 따른 피해효과 분석)

  • Roh Sam-Kew;Kim Tae-Hwan;Ham Eun-Gu
    • Journal of the Korean Institute of Gas
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    • v.3 no.3 s.8
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    • pp.45-50
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    • 1999
  • The LPG refueling station's explosion at Bucheon city was a major accident which with rare frequency of occurrence and large damage effect. Therefore, to prevent similar accident in the future from LPG charging stations which located in urban area. It needs to identify the damage effects of such facilities by comparing theoretically quantities risk and actual damage. The BLEVE effects from the accident showed similar damage effect in case of heat flux, however, the overpressure level reflected at the reduced distance by $15\%$. The structure damage to the near by area showed comparatively large heat radiation damage to the concrete structure strength and shape changes through heat flux while the overpressure effect was small.

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