• Title/Summary/Keyword: High temperature history

Search Result 190, Processing Time 0.027 seconds

Analysis of patients transported in ambulances by season and daily temperatures (계절 및 기온에 따른 119 구급대 환자 이송 건수 및 병력의 차이)

  • Lee, Kyoung-Youl;Lee, Jeong-Hyeok
    • The Korean Journal of Emergency Medical Services
    • /
    • v.23 no.3
    • /
    • pp.123-134
    • /
    • 2019
  • Purpose: This study aimed to analyze the number of patients with and without medical history transported to the emergency department due to changes in daily temperature and season. Methods: Data on emergency activity sheet and daily weather were collected from March 2016 to February 2017 in the city of Gyeonggi-do. In total, 13,531 patients were transferred to the emergency department in 119 ambulance. Data were analyzed using the Statistical Package for the Social Sciences (version 21). Results: The daily average number of patients transferred was the highest in August and September, i.e., the summer season. The higher the daily highest and lowest temperatures, higher the daily average number of patients transferred. In contrast, patients with medical history of hypertension, diabetes, heart disease, cerebrovascular disease, and pulmonary disease had a higher incidence of transfers in the winter season and on days with lower temperature. Conclusion: The results indicate that as people become more active during the summer when temperatures are high, the chances of daily emergencies increases, whereas patients with medical history are more likely to experience emergencies when the temperatures were lower. Hence, 119 ambulances will have to be prepared in advance to deal with this trend.

A study on the transient cooling process of a vertical-high temperature tube in an annular flow channel (환상유로에 있어서 수직고온관의 과도적 냉각과정에 관한 연구)

  • 정대인;김경근
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.10 no.2
    • /
    • pp.156-164
    • /
    • 1986
  • In the case of boiling on high temperature wall, vapor film covers fully or parcially the surface. This phenomenon, film boiling or transition boiling, is very important in the surface heat treatment of metal, design of cryogenic heat exchanger and emergency cooling of nuclear reactor. Mainly supposed hydraulic-thermal accidents in nuclear reactor are LCCA (Loss of Coolant Accident) and PCM (Power-Cooling Mismatch). Recently, world-wide studies on reflooding of high temperature rod bundles after the occurrence of the above accidents focus attention on wall temperature history and required time in transient cooling process, wall superheat at rewet point, heat flux-wall superheat relationship beyond the transition boiling region, and two-phase flow state near the surface. It is considered that the further systematical study in this field will be in need in spite of the previous results in ref. (2), (3), (4). The paper is the study about the fast transient cooling process following the wall temperature excursion under the CHF (Critical Heat Flux) condition in a forced convective subcooled boiling system. The test section is a vertically arranged concentric annulus of 800 mm long and 10 mm hydraulic diameter. The inner tube, SUS 304 of 400 mm long, 8 mm I.D, and 7 mm O.D., is heated uniformly by the low voltage AC power. The wall temperature measurements were performed at the axial distance from the inlet of the heating tube, z=390 mm. 6 chromel- alumel thermocouples of 76 .mu.m were press fitted to the inner surface of the heating tube periphery. To investigate the heat transfer characteristics during the fast transient cooling process, the outer surface (fluid side) temperature and the surface heat flux are computed from the measured inner surface temperature history by means of a numerical method for inverse problems of transient heat conduction. Present cooling (boiling) curve is sufficiently compared with the previous results.

  • PDF

A Study of the Arcing History in a Thermal Puffer Plasma Chamber with a Coupled Simulation (연성해석을 통한 열파퍼 플라즈마 챔버의 아크현상 이력에 관한 연구)

  • Lee, Jong-Chul;Heo, Joong-Sik;Kim, Youn-Jea
    • Proceedings of the KSME Conference
    • /
    • 2007.05b
    • /
    • pp.2506-2511
    • /
    • 2007
  • The coupled simulation is performed to find out the interaction of arc plasmas with surrounding materials in a thermal puffer plasma chamber. In order to be more realistic, PTFE nozzle ablation and Cu electrode evaporation, which are caused by high temperature of arc plasmas, are considered together. Pressure rise and temperature inside the chamber generated during the whole arcing history are investigated with the applied currents. It is very important to define how thermal flow and mass transfer are processing between the arc plasma and surrounding materials for further understanding complex physics inside the chamber. It is concluded that the result might be very useful to understand the mechanism happened inside and to design thermal puffer plasma chambers, but further experimental studies are required to verify the results for the more practical applications.

  • PDF

A study on the Physiological Character of living Space in Traditional Koaean House - Focsed on the rural house in Chonbuk province - (전통주거(傳統住居) 공간의 생리적(生理的) 특성(特性)에 관한 연구 - 전북지방 농촌주택(農村住宅)을 중심으로 -)

  • Kim, Yong-Jip
    • Journal of architectural history
    • /
    • v.8 no.2 s.19
    • /
    • pp.59-72
    • /
    • 1999
  • The purpose of this study is to find the spatial factors, strucure of living and activity in traditional Korean house through the Phiysiological view, Spatial factors of the house are concerned to the interior environment and sanitary condition, The elements of respiratory, nerve, temperature sence. vision, hearing, smelling have good condition and touch, pressure sence, pain, metabolism are poor in the house, Ventilation, Lighting, pleasant condition of interior environment are concerned to the elements that mentioned above and have most important meaning in the relation rate of space as 1st factor. And 2nd factor is for metabolism, housework and rest, 3rd factor ie for temperature sence, privacy and reproduction. The relation rate of factors concering interior environment are high in the upper class house. Anbang has important meaning in the relation of living structure and relation sequence of space is anbang, Konnonbang, kitchen, toilet, water place, auxiliary buildings. The relation rate of activity is high in interior space in winter and exterior space in summer.

  • PDF

Development of High-Temperature Heat Flux Gauge for Steel Quenching (강재 급속냉각용 고온 열유속게이지 개발)

  • Lee, Jungho
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.23 no.6
    • /
    • pp.323-330
    • /
    • 2010
  • The present study was motivated by increasing demands on quantitative measurements of the heat flux through the water cooling and quenching process of hot steel. The local heat flux measurements are employed by a novel experimental technique that has a function of high-temperature heat flux gauge in which test block assemblies are directly used to measure the heat flux variation during water cooling and quenching of hot steel. The heat flux can be directly achieved by Fourier's law and is also compared with numerical estimation which is solved by inverse heat conduction problem (IHCP). The high-temperature heat flux gauge developed in this study can be applicable to measure cooling rate and history during the actual cooling applications of steelmaking process. In addition, the measurement uncertainty of heat flux is calculated by a quantitative uncertainty analysis which is based on the ANSI/ASME PTC 19.1-2005 standard.

Transient cooling experiments with a cooper block in a subcooled flow boiling system (과냉비등류에 있어서 동블록을 이용한 과도적 냉각실험)

  • 정대인;김경근;김명환
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.11 no.1
    • /
    • pp.72-79
    • /
    • 1987
  • When the wall temperature is very high, a stable vapor film covers the heat transfer surface. The vapor film creates a strong thermal resistance when heat is transferred to the liquid though it. This phenomenon, called "film boiling" is very important in the heat treatment of metals, the design of cryogenic heat exchangers, and the emergency cooling of nuclear reactors. In the practical engineering problems of the transient cooling process of a high temperature wall, the wall temperature history, the variation of the heat transfer coefficients, and the wall superheat at the rewetting points, are the main areas of concern. These three areas are influenced in a complex fashion such factors as the initial wall temperature, the physical properties of both the wall and the coolant, the fluid temperature, and the flow state. Therefore many kinds of specialized experiments are necessary in the creation of precise thermal design. The object of this study is to investigate the heat transfer characteristics in the transient cooling process of a high temperature wall. The slow transient cooling experiment was carried out with a copper block of high thermal capacity. The block was 240 mm high and 79 mm O.D.. The coolant flowed throuogh the center of a 10 mm diameter channel in the copper block. In the copper block, three sheathed thermocouples were placed in a line perpendicular to the flow. These thermocouples were used to take measurements of the temperature histories of the copper block.

  • PDF

Study on Hydration Properties of High Strength Mass Concrete to apply Precast Concrete (PC 적용을 위한 고강도 매스콘크리트의 수화특성에 관한 연구)

  • Park, Heung-Lee;Kim, Sung-Jin;Lee, Hoi-Keun;Lee, Seung-Hoon;Park, Byung-Keun;Jung, Sang-Jin
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.04a
    • /
    • pp.661-664
    • /
    • 2008
  • As architectures have recently become high-risers and megastructured, stable high strength products have been ensured. Accordingly, use of precast concrete accouplement has been increased in order to facilitate air compression and rationalize construction. Since not only external heating but also internal temperature rise caused by the accumulation of cement hydration heat in manufacturing process, precast concrete members with large cross-section used for high-rise mega-structure's columns and beams may exhibit different temperature history compared to the precast concrete members for wall and sub-floor with relatively small cross-sections. Therefore, this study aims to elucidate the characteristics of temperature history of mass concrete members cast with high-strength concrete for precast concrete application. In this study, large cross-sectional precast concrete mock-up, unit cement quantity, and temperature histories in manufacturing precast concrete member under different curing condition were inclusively investigated.

  • PDF

An Experimental Study on the Effect of the Early Age Curing Condition on Mass Concrete (초기재령하의 양생조건이 매스콘크리트 온도관리에 미치는 영향 연구)

  • Kim, Kwang-Don;Kim, Chun-Ho;Lee, Choong-Yong;Hwang, Min-Kyu
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2006.11a
    • /
    • pp.685-688
    • /
    • 2006
  • As the concrete structure being large-sized and/or high-strengthened, the control of the hydration and curing temperature is made much account. This study, analysing the concrete temperature history from cylindric specimen and mock-up structures, investigates the effect of the early age curing condition and the optimum method of curing temperature control on mass concrete.

  • PDF

Effect of Hydration Heat Evolution on Autogenous Shrinkage of High Strength Concrete (초기수화발열이 고강도콘크리트의 자기수축특성에 미치는 영향)

  • 정해문;도변박지;하야도륭
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2003.05a
    • /
    • pp.95-100
    • /
    • 2003
  • The shrinkage of high strength/high performance concrete is very important property for the good working of a structure since it very often generates early age cracking due to thermal and autogenous shrinkage. Autogenous shrinkage occurs as a result of internal moisture depletion due to hydration and temperature-induced effects. The level of autogenous shrinkage occurring due to hydration also depends on temperature history at very early age. It is necessary that effect of temperature on autogenous shrinkage is investigated since the stress generated due to autogenous shrinkage is quantified. In this study, Effect of hydration heat evolution on autogenous shrinkage of high strength concretes with W/C=25-40% was investigated.

  • PDF

Properties of Temperature History of Lightweight Mortar for Fire Protection Covering Material in High Strength Concrete (고강도 콘크리트 내화피복용 경량 모르터의 온도이력 성상)

  • Lim, Seo-Hyung
    • Fire Science and Engineering
    • /
    • v.26 no.6
    • /
    • pp.45-50
    • /
    • 2012
  • The spalling causes the sever reduction of the cross sectional area with the exposure of the reinforcing steel, which originates a problem in the structural behaviour. By coating surface of high strength concrete with fireproof mortar, the high strength concrete is protected from the spalling in fire and the method to constrain the temperature increase of steel bar within the concrete. The purpose of this study is to investigate the temperature history properties of lightweight mortar using perlite and polypropylene fiber for fire protection covering material. For this purpose, selected test variables were the contents and length of polypropylene fiber. As a result of this study, it has been found that addition of polypropylene fiber to mortar modifies its pore structure and this causes the internal temperature to rise. And it has been found that a new lightweight mortar can be used in the fire protection covering material.