• Title/Summary/Keyword: Temperature history

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Field Application of Surface Insulation Curing Method to Cold Weather Concreting (한중콘크리트의 현장 표면단열 양생공법 시공사례 연구)

  • Kim Jong-Back;Lim Choon-Goun;Han Min-Cheol;Kim Seoung-Soo;Han Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.11a
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    • pp.25-28
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    • 2005
  • This study investigates the field application of surface insulation curing method, which combined double layer bubble sheet(DBS) and thick-curing-material(TCM) for cold weather concreting. According to the test, deck slab, curing only upper section with DBS and TCM, does not make big different temperature history with that, curing both upper and bottom section during daily average temperature 6.5t. It is concluded that combination of DBS and TCM in only upper section can be safely cured in early period of time during cold water concreting. The field test was carried out with this favourable data. The upper deck slab was insulated by combination of DBS and TCM, and the construction was surrounded by tent. in order to protect from outside wind. The test result shows that the lowest temperature of deck slab indicated 6$ ^{circ}C $. It demonstrated that this curing method can resist early frost and save construction cost in the side of management and saving labor cost, compared with previous method. In addition, the column specimen, combined both form and bubble board, exhibited favorable temperature history, due to internal hydration heat insulation effect.

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The Effect of Heat Curing Methods on the Temperature History of the Fly Ash Concrete Subjected to Extremely Low Temperature (복합보온양생 방법이 극저온 조건하 플라이애시 치환 콘크리트의 온도이력에 미치는 영향)

  • Han, Min-Cheol;Son, Ho-Jung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.3
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    • pp.85-90
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    • 2012
  • In this study, temperature profile of the fly ash concrete were studied in accordance with the change of heating curing method combination for the slab concrete in order to develop efficient protection method of the concrete subjected to $-20^{\circ}C$. The slab concretes with the size of $1200mm{\times}600mm{\times}200mm$ were fabricated with W/B of 50% and exposed to $-20^{\circ}C$ for 7 days. Five different combinations of heat curing methods were applied to the slab concrete specimen; two combinations of heat supplying by electrical heater and surface heat insulation material such as polyethylene film and quadrupled layer bubble sheet based on heat enclosure installment; three combinations of heating coil embedment and surface heat insulation materials such as polyethylene film, sawdust and quadrupled layer bubble sheet based on heat enclosure installment. Test results showed that by applying both heating coil and bubble sheet and heat enclosure, the concrete exposed to $-20^{\circ}C$ can be effectively protected from early-age frost damage.

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A Development of High Temperature Part History Management Program for Gas Turbine (발전용 가스터빈 고온부품 이력 관리 프로그램 개발)

  • Seok, Haejo;Lee, Youngho;Kang, Myoungcheol;Ki, Jayoung;Kong, Changduk
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.224-226
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    • 2017
  • This paper introduces the structure and the function of software developed to manage high temperature components of gas turbine for combined cycle power generation. In the case of high-temperature parts, the frequency of repair, regeneration and replacement is high. Therefore, the economic efficiency can be greatly improved through efficient management. In addition, the program provides a window type interface, which makes it easier for the user to use and can be extended to the whole system parts by expanding the program.

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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
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    • v.10 no.2
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    • pp.156-164
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    • 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.

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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
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    • 2006.11a
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    • pp.685-688
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    • 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.

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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
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    • v.8 no.2 s.19
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    • pp.59-72
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    • 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.

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Estimation of Thermal History in XLPE Insulated Cable during Heat Cycle Test (Heat Cycle Test에서 XLPE 절연체에 인가되는 열이력의 추정)

  • Kim, Young-Ho;Lee, Sang-Jin;Lee, Gun-Joo
    • Proceedings of the KIEE Conference
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    • 1998.07d
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    • pp.1425-1427
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    • 1998
  • The thermal history of XLPE insulated cable during heating cycle voltage test specified by IEC 840 was examined by DSC(differential scanning calorimetry) method, of which the principal is on the basis of the phenomenon that the crystals in polyethylene are rearranged as it is annealed near/below the melting temperature. From the result, it can be estimated that XLPE insulation near the conductor was exposed at the temperature of about $100^{\circ}C$ with the electrical stress through the test.

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Development of Convenient Software for Online Shelf-life Decisions for Korean Prepared Side Dishes Based on Microbial Spoilage

  • Seo, Il;An, Duck-Soon;Lee, Dong-Sun
    • Food Science and Biotechnology
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    • v.18 no.5
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    • pp.1243-1252
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    • 2009
  • User-friendly software was developed to determine the shelf-life of perishable Korean seasoned side dishes in real time based on growth models of spoilage and pathogenic microorganisms. In the program algorithm, the primary spoilage and fastest-growing pathogenic organisms are selected according to the product characteristics, and their growth is simulated based on the previously monitored or recorded temperature history. To predict the growth of spoilage organisms with confidence limits, kinetic models for aerobic bacteria or molds/yeasts from published works are used. Growth models of pathogenic bacteria were obtained from the literature or derived with regression of their growth rate data estimated from established software packages. These models are also used to check whether the risk of pathogenic bacterial growth exceeds that of food spoilage organisms. Many example simulations showed that the shelf-lives of the examined foods are predominantly limited by the growth of spoilage organism rather than by pathogenic bacterial growth.

Sexual Reproduction of Anthoplexaura dimorpha(Gorgonacea: Octocorallia) from Munseom, Jejudo Islands, Korea

  • Seo, Su-Yeon;Hwang, Sung-Jin;Song, Jun-Im
    • Animal cells and systems
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    • v.12 no.4
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    • pp.231-240
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    • 2008
  • The gorgonian coral Anthoplexaura dimorpha Kukenthal, 1908(Gorgonacea: Octocorallia) is abundant in Jejudo Islands, Korea. To investigate the sexual reproduction of this species, we surveyed the morphology and cycle of gametogenesis. 5-6cm long fragments from 3-7 randomly chosen colonies were collected monthly at a depth of 12-24m in the water surrounding Munseom from August 2003 to August 2005. This species was gonochoric with sex ratio of 1.86:1(female to male), and had one annual reproductive cycle affected by elevation of seawater temperature. Oogenesis was longer than spermatogenesis as 12 months in female and 6 months in male. The planulae were not observed from the field survey and histological sections, which suggested broadcast spawning for the reproductive mode in this species. The possible spawning events may occur after the seawater temperature attain to the annual peak in September.

Field Construction Applying the Insulating Method of Moderate-Cold Weather Concreting Using Double Bubble Sheets (2중 버블시트를 이용한 한랭기 콘크리트의 단열양생공법 현장적용)

  • Kim, Jong;Kim, Jong-Back;Jeon, Chung-Keun;Shin, Dong-An;Oh, Seon-Gyo;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2006.11a
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    • pp.29-32
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    • 2006
  • Experimental test results of field construction, Cheongju University Educational Liberal Art Building, applying the insulating curing method on slab concrete showed that the quality of concrete in fresh and hardened state satisfied all target values. Temperature history of slab concrete in A and B area secured more than $7.8{\sim}9.2^{\circ}C$ higher than outside atmosphere. After completing certain curing period of time on the surface of the structure, crack occurrence was not found. It is concluded that the preventing vaporization of moisture by the insulating curing method reduces plastic and drying shrinkage as welt as improves durability.

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