• 동의생리병리학회지
• /
• 제27권1호
• /
• pp.1-10
• /
• 2013

We can understand "Shanghanlun(傷寒論)" and "Wenbingtiaobian(溫病條辨)" which are major books on externally contracted diseases well by making a comparative study of their similarities and differences. After studying etiological causes and characteristics of disease, disease pattern, syndrome differentiation, transmutation rules, following conclusions are derived. While cold is an etiological cause of Cold damage and harms Yang qi, heat is an etiological cause of Warm disease and harms Yin qi. Cold damage and Warm disease have something in common in the respect of damage to fluid and humor and Yang qi. Exuberant heat symptom of Yang brightness disease and lesser yin heat transformation pattern have similar damage to fluid and humor as Warm disease does. Warm disease can reach qi collapse syndrome through damage to Yang qi following fluid and humor damage. In the respect of water qi, as Cold damage makes water-dampness retain easily due to cold congealing, dampness-draining diuretic medicinal and warm yang medicinal are used together. As warm disease damages fluid and humor, yin-tonifying medicinal is used and dampness-draining diuretic medicinal can be used in the case of Warm disease with dampness. In the respect of disease pattern, cold syndromes arise mostly by Cold damage except heat syndrome of grater yang disease, chest bind syndrome, stuffiness syndrome, reverting yin disease and yang brightness disease. Warm disease is classified as pure heat syndrome and heat syndrome with bowel excess, damage to yin, qi collapse or damage to blood.

• 한국지열·수열에너지학회논문집
• /
• 제18권1호
• /
• pp.1-11
• /
• 2022

As abnormal climates occur due to the increase in greenhouse gases at home and abroad, various problems such as human casualties, crop damage, energy depletion, and economic loss due to heat diseases, which are one of the extreme climate phenomena, are following one after another. In response, the government has established the 'Climate Crisis Response Special Committee' since 2018, when it recorded the greatest damage in history due to heat waves, and has been carrying out budget formation and reform of laws and systems every year to respond to heat waves. However, in relation to the heat wave damage reduction facility that is being expanded with a large budget, there is no prior research related to the degree of heat loss due to the use of the facility, the difference in effects between specific groups, and the economic effect that comes back compared to the invested budget. Therefore, from a midto long-term perspective, it is expected that it will be difficult to establish a clear direction for policy making. Therefore, in this study, representative facilities were selected according to the principle of heat reduction among the currently expanded heat damage reduction facilities, and a questionnaire survey was conducted for users of each reduction facility (waterfall, awning, pond, and elastic pavement). Accordingly, the change in the sense of heat according to the use of the heat damage reduction facility was checked, and the change in the sense of heat according to the group characteristics (gender, age, metabolic rate) was analyzed to examine the characteristics of the relationship between the facility and the users.

• Multiscale and Multiphysics Mechanics
• /
• 제1권2호
• /
• pp.171-188
• /
• 2016

Gradient enhanced theories of crystal plasticity enjoy great research interest. The focus of this work is on thermodynamically consistent modeling of grain size dependent hardening effects. In this contribution, we develop a model framework for damage coupled to gradient enhanced crystal thermoplasticity. The damage initiation is directly linked to the accumulated plastic slip. The theoretical setting is that of finite strains. Numerical results on single-crystalline metal showing the development of damage conclude the paper.

• Nuclear Engineering and Technology
• /
• 제44권5호
• /
• pp.523-534
• /
• 2012

The objective of this study was to experimentally investigate the effect of heat curing methods on the temperature history and strength development of slab concrete exposed to $-10^{\circ}C$. The goal was to determine proper heat curing methods for the protection of nuclear power plant structures against early-age frost damage under adverse (cold) conditions. Two types of methods were studied: heat insulation alone and in combination with a heating cable. For heat curing with heat insulation alone, either sawdust or a double layer bubble sheet (2-BS) was applied. For curing with a combination of heat insulation and a heating cable, an embedded heating cable was used with either a sawdust cover, a 2-BS cover, or a quadruple layer bubble sheet (4-BS) cover. Seven different slab specimens with dimensions of $1200{\times}600{\times}200$ mm and a design strength of 27 MPa were fabricated and cured at $-10^{\circ}C$ for 7 d. The application of sawdust and 2-BS allowed the concrete temperature to fall below $0^{\circ}C$ within 40 h after exposure to $-10^{\circ}C$, and then, the temperature dropped to $-10^{\circ}C$ and remained there for 7 d owing to insufficient thermal resistance. However, the combination of a heating cable plus sawdust or 2-BS maintained the concrete temperature around $5^{\circ}C$ for 7 d. Moreover, the combination of the heating cable and 4-BS maintained the concrete temperature around $10^{\circ}C$ for 7 d. This was due to the continuous heat supply from the heating cable and the prevention of heat loss by the 4-BS. For maturity development, which is an index of early-age frost damage, the application of heat insulation materials alone did not allow the concrete to meet the minimum maturity required to protect against early-age frost damage after 7 d, owing to poor thermal resistance. However, the combination of the heating cable and the heat insulating materials allowed the concrete to attain the minimum maturity level after just 3 d. In the case of strength development, the heat insulation materials alone were insufficient to achieve the minimum 7-d strength required to prevent early-age frost damage. However, the combination of a heating cable and heat insulating materials met both the minimum 7-d strength and the 28-d design strength owing to the heat supply and thermal resistance. Therefore, it is believed that by combining a heating cable and 4-BS, concrete exposed to $-10^{\circ}C$ can be effectively protected from early-age frost damage and can attain the required 28-d compressive strength.

• 한국안전학회지
• /
• 제28권3호
• /
• pp.80-87
• /
• 2013

Heat transfer analysis and thermal stress analysis for the concrete bridge was performed in order to investigate the damage of the concrete bridge by the fire of the vehicle. Changes in material properties, such as thermal conductivity, specific heat, density, elasticity, caused by temperature rise were considered. Heat transfer analysis and thermal stress analysis were performed according to the various location of the fire by ABAQUS. From the comparison of the numerical results, the degree of structural damage for the concrete bridge was investigated and considerations for the design of a concrete bridge against fire were identified.

• 한국지반환경공학회 논문집
• /
• 제22권11호
• /
• pp.15-21
• /
• 2021

도심지 지하에 매설된 열수송관 등 지하매설관이 점차 노후화함에 따라 파손에 의한 인적, 경제적 피해가 증가하고 있다. 외부로 노출되지 않아 파손 등 문제점을 즉시 확인하기 어려운 열수송관의 특징을 고려할 때, 시설물 유지관리를 통해 주기적으로 수집하는 이력정보를 기반으로 시설물의 상태를 간접적으로 확인하는 방법이 현실적이다. 본 논문에서는 열수송관 이력정보를 검토하여 파손확률과 연관성을 가지는 평가인자를 도출하고, 이를 통해 파손확률을 추정하는 방법론을 제시하고자 한다. 파손확률 추정을 위한 영향인자는 유럽의 사례, 국내 열수송관 관리기준 등을 분석해 도출하였으며, 데이터의 확보 가능성도 함께 고려하여 선정하였다. 열수송관 설치기준이 변경된 1999년을 기준으로 매설시기에 따라 2가지 파손확률 추정 함수를 달리 제시하고 관경, 용도, 관리주체 등 평가인자별 정보에 따른 가중치를 부여하여 파손확률을 보정하여 파손확률추정의 신뢰성을 확보하였다.

• Interaction and multiscale mechanics
• /
• 제4권3호
• /
• pp.207-217
• /
• 2011

International efforts have focused recently on the development of tungsten surfaces that can intercept energetic ionized and neutral atoms, and heat fluxes in the divertor region of magnetic fusion confinement devices. The combination of transient heating and local swelling due to implanted helium and hydrogen atoms has been experimentally shown to lead to severe surface and sub-surface damage. We present here a computational model to determine the relationship between the thermo-mechanical loading conditions, and the onset of damage and failure of tungsten surfaces. The model is based on thermo-elasticity, coupled with a grain boundary damage mode that includes contact cohesive elements for grain boundary sliding and fracture. This mechanics model is also coupled with a transient heat conduction model for temperature distributions following rapid thermal pulses. Results of the computational model are compared to experiments on tungsten bombarded with energetic helium and deuterium particle fluxes.

• Nuclear Engineering and Technology
• /
• 제54권1호
• /
• pp.84-96
• /
• 2022

In the worst case, a temporary ignition source (also known as transient combustibles) between two electrical panels can damage both panels. Mitigation strategies for electrical panel fires were previously developed using fire modeling and risk analysis. However, since they do not comply with deterministic fire protection requirements, it is necessary to analyze the boundary values at which combustibles may damage targets depending on various factors. In the present study, a sensitivity analysis of input variables related to the damage threshold of two electrical panels was performed for dimensionless geometry using a Fire Dynamics Simulator (FDS). A new methodology using a damage evaluation map was developed to assess the damage of the electrical panel. The input variables were the distance between the electrical panels, the vertical height of the fuel, the size of the fire, the wind speed and the wind direction. The heat flux was determined to increase as the vertical distance between the fuel and the panel decreased, and the largest heat flux was predicted when the vertical separation distance divided by one half flame length was 0.3-0.5. As the distance between the panels increases, the heat flux decreases according to the power law, and damage can be avoided when the distance between the fuel and the panel is twice the length of the panel. When the wind direction is east and south, to avoid damage to the electrical panel the distance must be increased by 1.5 times compared to no wind. The present scale model can be applied to any configuration where combustibles are located between two electrical panels, and can provide useful guidance for the design of redundant electrical panels.

• 대한안전경영과학회지
• /
• 제17권4호
• /
• pp.113-121
• /
• 2015

This study aims to examine the risk of electrical fire in places where electric heat wires are used. In general, the use of electric heating wires is becoming more common and prevalent in a bid to prevent increasing damage caused by freezing and bursting in residential water pipes, factory pipes and irrigation pipes in vinyl greenhouse and a variety of heat wire products are available in market with legal safety requirements imposed on them. However, the widespread use of anti-freezing burst heat wire products has caused increasing incidents of fire, which often fail to be incorporated into statistics due to quick onsite extinguishing and insignificant damage although damage is gradually on the rise. Against this backdrop, this study aims to look into the possibility of ignition caused by electric heat wires and the mechanism of how it turns into catching fire through overheat and short circuit tests for anti-freezing burst electrical heat wires (hereinafter called the 'heat wire') and expects to serve as the basis for further observations and analyses on the cause of fire and the process of ignition in a scientific manner.

• 동력기계공학회지
• /
• 제20권5호
• /
• pp.5-13
• /
• 2016

This study is on wear damage of the material for a molding machine that be used at finally cutting of metal beam made in roll forming process of vehicle bump beam process line. SKD11 steel was used with the material for cutting mold jig. In the cutting mold jig, Ti diffusion heat treatment after vacuum heat treatment was carried out for upgrade of surface hardness and anti-wear. Also, the heat treatments by various methods were performed to compare the wear damage degree against above the existing heat treatment. Wear loss and friction coefficient were obtained from wear test. And, micro Vickers hardness values were compared with damaged parts or not of cutting mold jig. Micro Vickers hardness value appeared higher at the undamaged part by Ti diffusion heat treatment. The micro Vickers hardness well followed a two-parameter Weibull probability distribution.