• Title/Summary/Keyword: internal temperature

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Thermal-pressure loading effect on containment structure

  • Kwak, Hyo-Gyoung;Kwon, Yangsu
    • Structural Engineering and Mechanics
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    • v.50 no.5
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    • pp.617-633
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    • 2014
  • Because the elevated temperature degrades the mechanical properties of materials used in containments, the global behavior of containments subjected to the internal pressure under high temperature is remarkably different from that subjected to the internal pressure only. This paper concentrates on the nonlinear finite element analyses of the nuclear power plant containment structures, and the importance for the consideration of the elevated temperature effect has been emphasized because severe accident usually accompanies internal high pressure together with a high temperature increase. In addition to the consideration of nonlinear effects in the containment structure such as the tension stiffening and bond-slip effects, the change in material properties under elevated temperature is also taken into account. This paper, accordingly, focuses on the three-dimensional nonlinear analyses with thermal effects. Upon the comparison of experiment data with numerical results for the SNL 1/4 PCCV tested by internal pressure only, three-dimensional analyses for the same structure have been performed by considering internal pressure and temperature loadings designed for two kinds of severe accidents of Saturated Station Condition (SSC) and Station Black-out Scenario (SBO). Through the difference in the structural behavior of containment structures according to the addition of temperature loading, the importance of elevated temperature effect on the ultimate resisting capacity of PCCV has been emphasized.

Study on the Mechanical Properties and Microstructure of Nickel Sulfamate Electroform (니켈쌀파메이트 전주층의 물성과 미세구조)

  • 김인곤
    • Journal of Surface Science and Engineering
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    • v.37 no.1
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    • pp.40-48
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    • 2004
  • Hardness and internal stress are very important in nickel electroforming. Nickel sulfamate bath has been widely used in electroforming because of its low internal stress and moderate hardness. Nickel sulfamate bath without chloride was chosen to investigated the effect of plating variable such as temperature, PH, current density and sodium naphthalene trisulfonate as addition agent on the hardness and internal stress. It was found that hardness increased with increasing temperature and decreasing current density and ranged from 150∼310 DPH. The hardness was highest at $55^{\circ}C$ and 10∼40 mA/$\textrm{cm}^2$. The internal stress increased with increasing current density and decreasing temperature. It was minimum at PH 3.0∼3.8. Low internal stress within $\pm$1,500 psi was obtained at both $50^{\circ}C$ and $55^{\circ}C$ in 10-20 mA/$\textrm{cm}^2$. The addition of sodium naphthalene trisulfonate was found to be effective in refine columnar grains thus resulted in decreasing internal stress, increasing hardness and improving brightness.

Variations of the Inside Temperature of Greenhouse According to Shading Methods (차광 방법에 따른 온실내부의 온도 변화(농업시설))

  • 이현우;이석건;김길동;이종원
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2000.10a
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    • pp.321-326
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    • 2000
  • This study was performed to analyze the variation of inside temperature of greenhouse according to shading methods. We used two shading method of external and internal method. The shading effect of external screen was superior to internal screen. Soil temperature of greenhouse without screen was higher than outside soil temperature, but the value of greenhouse with internal and external screen was lower than outside.

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Effect of Cooking on the Food Safety of Cutlet - Changes of Internal Temperature, Color, and Indicator Organisms - (가열 처리에 따른 커틀릿의 식품안전성 확보 조건 - 내부 중심온도, 색도 및 위생지표미생물을 중심으로 -)

  • Kim, Jong-Gyu;Kim, Joong-Soon
    • Journal of Environmental Health Sciences
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    • v.41 no.2
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    • pp.82-89
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    • 2015
  • Objectives: This study was performed to investigate the effect of cooking time on the internal temperature and color of cutlets and the reduction of indicator organisms in cutlets by cooking. Methods: Three kinds of commercially packed frozen cutlets (pork, chicken and fish cutlets), were purchased from local markets. The cutlets were cooked in a frying pan at $180^{\circ}C$ for four minutes. Internal temperature was measured with a food thermometer. Color was measured using a Hunter spectrocolorimeter. Aerobic colony counts, coliforms, and Escherichia coli were determined according to the Food Code of Korea. Results: The internal cooked temperature of every cutlet reached over $74^{\circ}C$, the temperature considered safe, after three minutes, while external temperature reached this level in two minutes (p < 0.001). The instrumental color value as lightness (L) in the cooked cutlets significantly changed (p < 0.001) after one minute. The level of aerobic colony counts of fresh cutlets was under the specification and was reduced to one tenth its level in the cooked cutlets. Coliforms and E. coli were not detected in all samples. The internal temperature of the cutlets was significantly affected by cooking time and weight (p < 0.001). The interaction effect of time and weight was also significant (p < 0.001), and time was the more influential factor. Conclusion: The results of this study indicate that the sampled cutlets should be cooked for a minimum of three minutes or more in order to ensure food safety. The results also indicate that if consumers cease cooking based on external temperature or color, there will be a risk of inadequate cooking.

The correlation between average temperature & precipitation and Pattern Identification of the patients with stroke (중풍환자의 변증(辨證)과 기온 및 강수여부와의 상관성에 관한 연구)

  • Ma, Mi-Jin;Kim, Bo-Ram;Kim, Mi-Kyung;Choi, Dong-Jun;Han, Chang-Ho;Jung, Seung-Hyun;Shin, Gil-Jo;Lee, Won-Chul
    • The Journal of the Society of Stroke on Korean Medicine
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    • v.9 no.1
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    • pp.8-13
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    • 2008
  • Objectives : This study was to investigated the correlation between average temperature & precipitation and pattern identification of the patients with stroke. Methods : 115 stroke patients within 30days of onset were registered during the study period. Pattern identification of stroke was classified into Fire and heat, Turbid phlegm and others. We took the mean of average temperature according to pattern identification and analyzed pattern identification into two groups according to climatological normal of average temperature in Seoul. We also analyzed pattern identification into two groups according to existence of precipitation. Results : Heat and fire, and other type of pattern identification had high frequency when average temperature was higher than 12.2℃. And there was no correlation between precipitation and pattern identification of stroke.

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Performance Analysis of R404A Refrigeration System with Internal Heat Exchanger Using R744 as a Secondary Refrigerant (R744를 2차 냉매로 사용하는 내부열교환기 부착 R404A 냉동시스템의 성능 분석)

  • Oh, Hoo-Kyu;Son, Chang-Hyo;Yi, Wen-Bin;Jeon, Min-Ju
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.25 no.10
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    • pp.548-554
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    • 2013
  • A thermodynamic analysis of the R404A refrigeration system with an internal heat exchanger using R744 as a secondary refrigerant is presented in this paper to optimize the design for operating parameters of the system. The main results are summarized as follows: The COP increases with increasing subcooling and superheating degree of R404A, internal heat exchanger and compression efficiency of the R404A cycle and evaporating temperature of the R744 cycle and decreasing temperature difference of the cascade heat exchanger and condensing temperature of the R404A cycle. The mass flow ratio decreases with increasing evaporating temperature of the R744 cycle and internal heat exchanger efficiency of the R404A cycle and decreasing subcooling and superheating degree of the R744 cycle, temperature difference of the cascade heat exchanger and condensing temperature of the R404A cycle.

Analytical Estimation of Internal Temperature of RC Beam under Fire (화재시 철근 콘크리트 보 내부 온도의 해석적 추정)

  • Lee Eun-ju;Shin Mi-kyung;Kang Ji-yeon;Shin Yeong-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.548-551
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    • 2004
  • The main purpose of this study is to estimate the internal temperature of RC beam under fire. For this purpose, the finite difference method was used. In the previous studies, the structural behavior of fire damaged RC beams was investigated through experiments. The result was concluded that The high temperature affects the properties of concrete such as the elastic modulus, the compressive strength. The internal temperature Estimation of the concrete is helpful for understanding the structural behavior of fire damaged RC beams. Especially, high strength concrete has more spalling than normal strength one. So, this study is performed analysis of internal temperature of RC beam considering spalling.

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Mechanical Behavior and Characteristics of Internal Temperature and Relative Humidity of Concrete at Early Age (초기재령 콘크리트의 역학적 특성 및 온·습도 거동 특성 분석)

  • Park, Cheol Woo;Lee, Bong Hak;Hong, Seung Ki
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.6
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    • pp.184-194
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    • 2011
  • This study is to analyze the internal temperature and relative humidity of concrete at early age, as well as the mechanical behavior. Three different levels of cement unit content were cosidered as an experimental variable. In order to measure internal temperature and relative humidity immediately after concrete placement, this study developed a unique measuring device, which provided reliable results. Different cement content did not significantly affected the strengths including compressive, tensile and flexural strength and after 7 days of curing, strengths did not increase noticeably. Internal temperature reached the maximum about 11 hours later the placement and decreased after removal of forms. The internal temperature varied depending on the location and the exposure condition. In addition, the internal relative humidity was more affected by the exposure condition rather than the cement content.

Diagnostic Tool for Cold Sensation of Hands: A Preliminary Study (수부냉증 진단방법에 관한 기초연구)

  • Ko, Seung-woo;Park, Jong-ju;Kong, Kyung-hwan;Go, Ho-yeon
    • The Journal of Internal Korean Medicine
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    • v.36 no.3
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    • pp.228-235
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    • 2015
  • Objectives: The aim of this study was to find an effective medical device to detect cold sensation of hands. Methods: Patients with cold sensation of hands (N=42) were recruited in July 2013. We surveyed patients’ general characteristics, severity of cold sensation, body temperature in Nogung (PC8) and Hyeopbaek (LU4) measured with a digital thermometer, digital infrared thermal imaging, and pulse wave velocity. Results: The relation between severity of cold sensation and temperature in Nogung (PC8) and Hyeopbaek (LU4) was statistically significant. The results showed a higher correlation of severity of cold sensation with Nogung (PC9) than with Hyeopback (LU4) temperature. No other indices were statistical significant. Conclusions: Measuring the Nogung (PC9) temperature is most reasonable for assessing the severity of cold sensation of hands. To generalize this result, however, a large-scale study is warranted.

The Back Side Temperature Variation According to Color of Sandwich Panel and Internal Core Material (샌드위치 패널의 외부 색상과 내부 심재에 따른 이면 온도 변화)

  • Park, Jun-Seo;Kim, Bong-Joo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.25-26
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    • 2023
  • The internal core material and external color of a sandwich panel have a significant impact on the performance of the sandwich panel. For use on roofs and walls, the internal core material and external color must be considered. Therefore, the surface and back side temperatures were measured for each exterior color and inner core material type. For the internal core materials, urethane foam and Expanded Poly Styrene(EPS), which are core materials mainly used in sandwich panels, were selected. As colors, black and ivory were selected according to brightness, and a total of five colors were selected: red, blue, and green, which are the three primary colors of light. As a result, there were differences in surface and temperature depending on the external color and type of internal core material. Regardless of the color, the temperature was measured lower for panels with urethane foam than for panels with an internal core of EPS. This is believed to have been influenced by the difference in thermal conductivity of urethane foam being 0.023W/(m·K) and that of EPS being 0.032W/(m·K). In addition, panels with a black exterior color were found to have higher surface and back temperatures than panels of other colors, and ivory-colored panels had lower back temperatures regardless of the core material. This is proportional to the brightness and light-absorbing characteristics.

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