• Title/Summary/Keyword: heat-damage

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A Study on the Wave Formation and Hair Damage Levels Relating to the Uses of Treatments for Heat Permanent Waves

  • Kim, Kwan-Ok;Kim, Sung-Nam
    • Journal of Fashion Business
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    • v.12 no.6
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    • pp.1-10
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    • 2008
  • Public interest in healthy hairs gets growing as damaged hairs are seen more frequently with the generalization of heat permanent waves. For this study, experiments have been conducted to understand the influences on the changes in physical and morphological features of wave forms and damaged hairs, by collecting virgin hairs from the women in their mid-20's, who had not experienced chemical applications, and by dividing the applications of heat perm hair treatments, PPT(for pre-treatment) and LPP(for post-treatment), into the pre-treatment, the post-treatment, the pre & post-treatment, and the non-treatment. For the wave formations, curl waves were investigated by the bare eyes using the pictures taken by a digital camera. For the comparison of physical features, the experiments of tensile strength and elongation were done and their mean values were found. For the observations of morphological features, the pictures were taken by SEM for comparison. As for the findings, regarding the curl wave shapes of hairs, the most even and elastic S curl was formed in the case of non-treatment. In the physical features, both of the tensile strength and elongation showed a decreasing tendency in line with the hair damage levels, and the case of the pre & post-treatment indicated the tendency most similar to the control group. In the morphological features of the cuticle, observed with an SEM, the pre-treatment showed the higher possibility of reducing the cuticle damages than the post-treatment did. LPP was found to play the role of protective membrane for the post-treatment, and the pre & post-treatment turned out to reduce most effectively the cuticle damages.

The Experience and Psychological Characteristics of Thermal Diseases from the Heatwave of Construction Workers (건설 노동자의 폭염으로 인한 온열질환 증상의 경험과 심리적 특성)

  • Lee, Jae Young;Lee, Sungsu
    • Journal of the Society of Disaster Information
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    • v.16 no.4
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    • pp.747-757
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    • 2020
  • Purpose: This study noted that even similar environmental conditions caused by the heat wave were differentiated depending on the internal characteristics of the individual, so there was a difference in the extent of the damage. Thus, the relationship between individual psychological characteristics and experiences of the symptoms of thermal diseases was analyzed. Method: The influence of construction workers was analyzed through questioning of individual characteristics and psychological measures of self-esteem, self-esteem, and personality that may be related to heat wave damage, depending on whether they have experienced symptoms of thermal diseases. Results: Logistic regression shows that responsibility affects positive (+) experience of symptoms of heat disease and self-esteem in groups negatively (-) experience of symptoms of heat illness. Conclusion: This study presented basic data as the first study to analyze obsessive compulsive, self-respect and personality of construction workers who are vulnerable to heat waves to identify the psychological characteristics of victims of heat waves.

Characteristics of Heat Waves From a Disaster Perspective

  • Kim, Do-Woo;Kwon, Chaeyoung;Kim, Jineun;Lee, Jong-Seol
    • Journal of Preventive Medicine and Public Health
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    • v.53 no.1
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    • pp.26-28
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    • 2020
  • In September 2018, heat waves were declared to be a type of natural disaster by the Framework Act on the Management of Disasters and Safety. The present study examined the characteristics of heat waves from the perspectives of meteorological phenomena and health damage. The government's efforts to minimize the damages incurred by heat waves are summarized chronologically. Furthermore, various issues pertaining to heat waves that are being raised in our society despite the government's efforts are summarized by analyzing big data derived from reported news and academic articles.

Study on the development of extreme heat health watch warning system threshold for personal injury prevention (폭염시기 인명 피해 예방을 위한 폭염특보기준 설정에 관한 연구)

  • Park, Jong-Kil;Jung, Woo-Sik;Kim, Eun-Byul;Song, Jeong-Hui
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.385-388
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    • 2008
  • Recently, occurrence frequency of natural disaster decrease but scale of damage increase remarkably by the Climate change due to global warming. Especially, extreme heat become more critical wether problem in the Korean Peninsula. But, we don't have exact threshold about extreme heat. Therefore, to assess the influences by the extreme heat on personal injury, we analyzed statistics on the causes of the daily mortality. And we developed a threshold for extreme heat health watch warning system.

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On modeling of fire resistance tests on concrete and reinforced-concrete structures

  • Ibrahimbegovic, Adnan;Boulkertous, Amor;Davenne, Luc;Muhasilovic, Medzid;Pokrklic, Ahmed
    • Computers and Concrete
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    • v.7 no.4
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    • pp.285-301
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    • 2010
  • In this work we first review the statistical data on large fires in urban areas, presenting a detailed list of causes of fires, the type of damage to concrete and reinforced concrete structures. We also present the modern experimental approach for studying the fire-resistance of different structural components, along with the role of numerical modeling to provide more detailed information on quantifying the temperature and heat flux fields. In the last part of this work we provide the refined models for assessment of fire-induced damage in structures built of concrete and/or reinforced-concrete. We show that the refined models of this kind are needed to provide a more thorough explanation of damage and to complete the damage assessment and post-fire evaluations.

PX-An Innovative Safety Concept for an Unmanned Reactor

  • Yi, Sung-Jae;Song, Chul-Hwa;Park, Hyun-Sik
    • Nuclear Engineering and Technology
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    • v.48 no.1
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    • pp.268-273
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    • 2016
  • An innovative safety concept for a light water reactor has been developed at the Korea Atomic Energy Research Institute. It is a unique concept that adopts both a fast heat transfer mechanism for a small containment and a changing mechanism of the cooling geometry to take advantage of the potential, thermal, and dynamic energies of the cold water in the containment. It can bring about rapid cooling of the containment and long-term cooling of the decay heat. By virtue of this innovative concept, nuclear fuel damage events can be prevented. The ultimate heat transfer mechanism contributes to minimization of the heat exchanger size and containment volume. A small containment can ensure the underground construction, which can use river or seawater as an ultimate heat sink. The changing mechanism of the cooling geometry simplifies several safety systems and unifies diverse functions. Simplicity of the present safety system does not require any operator actions during events or accidents. Therefore, the unique safety concept of PX can realize both economic competitiveness and inherent safety.

BACKUP AND ULTIMATE HEAT SINKS IN CANDU REACTORS FOR PROLONGED SBO ACCIDENTS

  • Nitheanandan, T.;Brown, M.J.
    • Nuclear Engineering and Technology
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    • v.45 no.5
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    • pp.589-596
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    • 2013
  • In a pressurized heavy water reactor, following loss of the primary coolant, severe core damage would begin with the depletion of the liquid moderator, exposing the top row of internally-voided fuel channels to steam cooling conditions on the inside and outside. The uncovered fuel channels would heat up, deform and disassemble into core debris. Large inventories of water passively reduce the rate of progression of the accident, prolonging the time for complete loss of engineered heat sinks. The efficacy of available backup and ultimate heat sinks, available in a CANDU 6 reactor, in mitigating the consequences of a prolonged station blackout scenario was analysed using the MAAP4-CANDU code. The analysis indicated that the steam generator secondary side water inventory is the most effective heat sink during the accident. Additional heat sinks such as the primary coolant, moderator, calandria vault water and end shield water are also able to remove decay heat; however, a gradually increasing mismatch between heat generation and heat removal occurs over the course of the postulated event. This mismatch is equivalent to an additional water inventory estimated to be 350,000 kg at the time of calandria vessel failure. In the Enhanced CANDU 6 reactor ~2,040,000 kg of water in the reserve water tank is available for prolonged emergencies requiring heat sinks.

Korean Red Ginseng alleviates neuroinflammation and promotes cell survival in the intermittent heat stress-induced rat brain by suppressing oxidative stress via estrogen receptor beta and brain-derived neurotrophic factor upregulation

  • Iqbal, Hamid;Kim, Si-Kwan;Cha, Kyu-Min;Jeong, Min-Sik;Ghosh, Prachetash;Rhee, Dong-kwon
    • Journal of Ginseng Research
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    • v.44 no.4
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    • pp.593-602
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    • 2020
  • Background: Heat stress orchestrates neurodegenerative disorders and results in the formation of reactive oxygen species that leads to cell death. Although the immunomodulatory effects of ginseng are well studied, the mechanism by which ginseng alleviates heat stress in the brain remains elusive. Methods: Rats were exposed to intermittent heat stress for 6 months, and brain samples were examined to elucidate survival and antiinflammatory effect after Korean Red Ginseng (KRG) treatment. Results: Intermittent long-term heat stress (ILTHS) upregulated the expression of cyclooxygenase 2 and inducible nitric oxide synthase, increasing infiltration of inflammatory cells (hematoxylin and eosin staining) and the level of proinflammatory cytokines [tumor necrosis factor α, interferon gamma (IFN-γ), interleukin (IL)-1β, IL-6], leading to cell death (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay) and elevated markers of oxidative stress damage (myeloperoxidase and malondialdehyde), resulting in the downregulation of antiapoptotic markers (Bcl-2 and Bcl-xL) and expression of estrogen receptor beta and brain-derived neurotrophic factor, key factors in regulating neuronal cell survival. In contrast, KRG mitigated ILTHS-induced release of proinflammatory mediators, upregulated the mRNA level of the antiinflammatory cytokine IL-10, and increased myeloperoxidase and malondialdehyde levels. In addition, KRG significantly decreased the expression of the proapoptotic marker (Bax), did not affect caspase-3 expression, but increased the expression of antiapoptotic markers (Bcl-2 and Bcl-xL). Furthermore, KRG significantly activated the expression of both estrogen receptor beta and brain-derived neurotrophic factor. Conclusion: ILTHS induced oxidative stress responses and inflammatory molecules, which can lead to impaired neurogenesis and ultimately neuronal death, whereas, KRG, being the antioxidant, inhibited neuronal damage and increased cell viability.

Simulation Analysis of Bio-Methane Decomposition Using Solar Thermal Energy (태양열 이용 바이오메탄 분해 해석연구)

  • Kim, Haneol;Lee, Sangnam;Lee, Sang Jik;Kim, Jongkyu
    • New & Renewable Energy
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    • v.17 no.1
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    • pp.40-49
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    • 2021
  • In this study, the optical properties, heat transfer capabilities and chemical reaction performance of a methane thermal decomposition reactor using solar heat as a heat source were numerically analyzed on the basis of the cavity shape. The optical properties were analyzed using TracePro, a Monte Carlo ray tracing-based program, and the heat transfer analysis was performed using Fluent, a CFD program. An indirect heating tubular reactor was rotated at a constant speed to prevent damage by the heat source in the solar furnace. The inside of the reactor was filled with a porous catalyst for methane decomposition, and the outside was insulated to reduce heat loss. The performance of the reactor, based on cavity shape, was calculated when solar heat was concentrated on the reactor surface and methane was supplied into the reactor in an environment with a solar irradiance of 700 W/㎡, a wind speed of 1 m/s, and an outdoor temperature of 25℃. Thus, it was confirmed that the heat loss of the full-cavity model decreased to 13% and the methane conversion rate increased by 33.5% when compared to the semi-cavity model.