• Title/Summary/Keyword: Korea temperature

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Development of a structural integrity evaluation program for elevated temperature service according to ASME code

  • Kim, Nak Hyun;Kim, Jong Bum;Kim, Sung Kyun
    • Nuclear Engineering and Technology
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    • v.53 no.7
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    • pp.2407-2417
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    • 2021
  • A structural integrity evaluation program (STEP) was developed for the high temperature reactor design evaluation according to the ASME Boiler and Pressure Vessel Code (ASME B&PV), Section III, Rules for Construction of Nuclear Facility Components, Division 5, High Temperature Reactors, Subsection HB. The program computerized HBB-3200 (the design by analysis procedures for primary stress intensities in high temperature services) and Appendix T (HBB-T) (the evaluation procedures for strain, creep and fatigue in high temperature services). For evaluation, the material properties and isochronous curves presented in Section II, Part D and HBB-T were computerized for the candidate materials for high temperature reactors. The program computerized the evaluation procedures and the constants for the weldment. The program can generate stress/temperature time histories of various loads and superimpose them for creep damage evaluation. The program increases the efficiency of high temperature reactor design and eliminates human errors due to hand calculations. Comparisons that verified the evaluation results that used the STEP and the direct calculations that used the Excel confirmed that the STEP can perform complex evaluations in an efficient and reliable way. In particular, fatigue and creep damage assessment results are provided to validate the operating conditions with multiple types of cycles.

Construction of Super-Resolution Convolutional Neural Network Model for Super-Resolution of Temperature Data (기온 데이터 초해상화를 위한 Super-Resolution Convolutional Neural Network 모델 구축)

  • Kim, Yong-Hoon;Im, Hyo-Hyuk;Ha, Ji-Hun;Park, Kun-Woo;Kim, Yong-Hyuk
    • Journal of the Korea Convergence Society
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    • v.11 no.8
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    • pp.7-13
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    • 2020
  • Meteorology and climate are closely related to human life. By using high-resolution weather data, services that are useful for real-life are available, and the need to produce high-resolution weather data is increasing. We propose a method for super-resolution temperature data using SRCNN. To evaluate the super-resolution temperature data, the temperature for a non-observation point is obtained by using the inverse distance weighting method, and the super-resolution temperature data using interpolation is compared with the super-resolution temperature data using SRCNN. We construct an SRCNN model suitable for super-resolution of temperature data and perform super-resolution of temperature data. As a result, the prediction performance of the super-resolution temperature data using SRCNN was about 10.8% higher than that using interpolation.

Comparative study on the contents of marker compounds and anti-inflammatory effects of Gamisoyo-san decoction according to storage temperature and periods (가미소요산 전탕팩의 보관 온도 및 기간에 따른 지표 성분 함량 및 항염증 효능 비교 연구)

  • Jin, Seong Eun;Seo, Chang-Seob;Lee, Nari;Shin, Hyeun-Kyoo;Ha, Hyekyung
    • The Journal of Korean Medicine
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    • v.39 no.1
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    • pp.22-34
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    • 2018
  • Objectives: The purpose of this study is to investigate changes of the marker compounds and anti-inflammatory effect of Gamisoyo-san decoction (GMSYS) depending on storage temperature and periods. Methods: GMSYS was stored at room temperature or refrigeration for 12 months. According to storage temperature and periods, pH and sugar content of GMSYS were measured. To determine the marker compounds of GMSYS, high-performance liquid chromatography analysis was performed. To estimate the anti-inflammatory effect of GMSYS, LPS-induced pro-inflammatory mediators and cytokines were measured in RAW 264.7 cells. Results: There was no change in pH and sugar content depending on storage temperature and periods of GMSYS. The contents of gallic acid and mangiferin in both of room temperature and refrigerated decoctions reduced with increasing storage periods. Chlorogenic acid was time-dependently decreased in case of stored at room temperature. GMSYS significantly inhibited the LPS-induced production of nitric oxide, prostaglandin $E_2$ ($PGE_2$) and IL-6 in RAW 264.7 cells. These effects equally maintained up to 3 months at both of room temperature and refrigeration. Since 4 months, the inhibitory effect of GMSYS on LPS-induced $PGE_2$ production was time-dependently reduced, and the decrease in $PGE_2$ inhibitory effect of decoction stored at refrigeration was lower than that of stored at room temperature. Conclusions: Our results indicate that the anti-inflammatory effect of GMSYS are maintained up to 12 months, but it shows optimal efficacy up to 3 months. It is recommended to store in a refrigeration for short periods since some components decrease as storage periods becomes longer.

A Study on the High Temperature Tensile Characteristics of Lap Weld of 15Cr Ferritic Stainless Steels (15Cr 페라이트계 스테인리스강의 겹침용접부 고온인장 특성에 관한 연구)

  • Lee, Young-Gi;Lee, Gyeong-Cheol;Kim, Jae-Seong;Han, Do-Seok;Oh, Seung-Taek;Lee, Bo-Young
    • Journal of Welding and Joining
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    • v.26 no.5
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    • pp.60-65
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    • 2008
  • Ferritic stainless steels of the 400 series have been available for automotive exhaust system, heat exchanger, radiater etc. in various industrial because heat resistance, corrosion resistance and strength are excellent. Especially, automotive exhaust system is required good heat resistance because typical temperature of exhaust system exposed during operation of engine is reach up to $800^{\circ}C$. However, research for effect of high temperature in ferritic stainless steels is not enough. In this study, high temperature tensile properties of lap weld of ferritic stainless steels(STS 429) were investigated. In accordance with heat input, lap welds had been produced and were evaluated at high temperature($800^{\circ}C$) to compare high temperature tensile properties. In addition, room temperature tensile tests were carried out for non-aging and aging specimens. As a result of R.T tensile test, non-aging specimens were fractured in base metal except for low heat input specimen and aging specimens were fractured in weld metal. Also high temperature tensile test were carried out by aging specimen. After high temperature tensile test, fracture of aged specimen was occurred in base metal except for low heat input specimen. Fracture surface of low heat input specimen in weld metal was confirmed as brittle fracture with observation using scanning electron microscope(SEM). Significant decrease in ultimate tensile strength (between 82 and 85%) was observed for aged ferritic stainless steels(STS 429) when tested at high temperature.

Effect of Thermal Aging Temperature on Weight Loss and Glass Transition Temperature of Epoxy Adhesives (열화 온도가 에폭시 접착제의 질량변화 및 유리전이온도에 미치는 영향)

  • Park, Soo-Jin;Kim, Jong-Hak;Joo, Hyeok-Jong;Kim, Joon-Hyung;Jin, Fan-Long
    • Elastomers and Composites
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    • v.41 no.1
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    • pp.19-26
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    • 2006
  • In this study, the effect of thermal aging temperature on the weight loss, glass transition temperature, and morphology of epoxy adhesives cured with amine (D-230), amide (G-5022), and anhydride (HN-2200) was investigated. As a result, the weight loss of three specimens was increased with increasing the thermal aging temperature. The result was attributed to the thermal aging which was occurred at the surface of adhesive specimens at high aging temperature, resulting in increasing the weight loss of the specimens. According to the DSC result, the glass transition temperature of DGEBA/D-230 and DGEBA/G-5022 samples war increased as the aging temperature increased, whereas the glass transition temperature of DGEBA/HN-2200 samples was constant above aging temperature of $150^{\circ}C$ and aging tine of 7 days. The SEM result indicated that the surface of DGEBA/G-5022 specimen showed more rough topography than that of DGEBA/D-230 or DGEBA/HN-2200 specimen after thermal aging. This could be correlated with the result of weight loss.

Effect of Phenyl Vinyl Methyl Silicone (PVMQ) on Low Temperature Sealing Performance of Fluorosilicone Composites

  • Lee, Jin Hyok;Bae, Jong Woo;Choi, Myoung Chan;Yun, Yu-Mi;Jo, Nam-Ju
    • Elastomers and Composites
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    • v.56 no.4
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    • pp.209-216
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    • 2021
  • In this study, we observed the mechanical properties, thermal stability, and low temperature sealing performance of fluorosilicone elastic composites. When the blend ratio of Phenyl vinyl methyl silicone (PVMQ) was increased, the tensile strength, modulus at 100%, and compression set were decreased. The thermal stability of fluorosilicone elastic composites showed a similar tendency. These were caused by poorer green strength of PVMQ than Fluorosilicone rubber (FVMQ). The change in the tensile strength and elongation at -40℃ showed a decreasing tendency with increasing PVMQ blend ratio. By increasing the PVMQ blend ratio, low-temperature performance was improved. The Dynamic mechanical analysis (DMA) results showed that Tg was decreased and low-temperature performance was improved with increasing PVMQ blend ratio. However tanδ was decreased becaused of the poor green strength and elasticity of PVMQ. From a hysteresis loss at -40℃, the hysteresis loss value was increased and fluorosilicone elastic composites showed the decreasing tendency of elasticity with increasing PVMQ blend ratio. From the TR test, TR10 was decreased with increasing PVMQ blend ratio. FS-4 (45% PVMQ blended composites) showed a TR10 of -68.0℃ that was 5℃ lower than that of FS-1 (100% FVMQ). The gas leakage temperature was decreased with increasing PVMQ blend ratio. The gas leakage temperature of FS-4 was -69.2℃ that was 5℃ lower than that of FS-1. Caused by the polymer chain started to transfer from a glassy state to a rubbery state and had a mobility of chain under Tg, the gas leakage temperature showed a lower value than Tg. The sealing performance at low temperature was dominated by Tg that directly affected the mobility of the polymer chain.

Application of Back-propagation Algorithm for the forecasting of Temperature and Humidity (온도 및 습도의 단기 예측에 있어서 역전파 알고리즘의 적용)

  • Jeong, Hyo-Joon;Hwang, Won-Tae;Suh, Kyung-Suk;Kim, Eun-Han;Han, Moon-Hee
    • Journal of Environmental Impact Assessment
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    • v.12 no.4
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    • pp.271-279
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    • 2003
  • Temperature and humidity forecasting have been performed using artificial neural networks model(ANN). We composed ANN with multi-layer perceptron which is 2 input layers, 2 hidden layers and 1 output layer. Back propagation algorithm was used to train the ANN. 6 nodes and 12 nodes in the middle layers were appropriate to the temperature model for training. And 9 nodes and 6 nodes were also appropriate to the humidity model respectively. 90% of the all data was used learning set, and the extra 10% was used to model verification. In the case of temperature, average temperature before 15 minute and humidity at present constituted input layer, and temperature at present constituted out-layer and humidity model was vice versa. The sensitivity analysis revealed that previous value data contributed to forecasting target value than the other variable. Temperature was pseudo-linearly related to the previous 15 minute average value. We confirmed that ANN with multi-layer perceptron could support pollutant dispersion model by computing meterological data at real time.

Improvement of Low Temperature Fuel Characteristics by Pour Point Depressant (유동점 강하제에 의한 바이오디젤 저온특성 향상)

  • Lim, Young-Kwan;Lee, Joung-Min;Jeong, Choong-Sub;Kim, Jong-Ryeol;Yim, Eui-Soon
    • Tribology and Lubricants
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    • v.27 no.2
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    • pp.109-114
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    • 2011
  • The low temperature characteristics of automotive diesel have been legally regulated due to the fact that solid particle in diesel at low temperature can cause severe problems in the vehicle. The biodiesel is well known for eco-friendly fuel, which is one of the most popular alternative petrodiesel, but it is easy to solidified at low temperature than petrodiesel at low temperature. For that reason, in this study, we investigated the low temperature fuel characteristics of diesel-biodiesel blends which were prepared to mix 6 different kinds of biodiesel to winter diesel fuel, respectively. Also, we confirmed to improve low temperature fuel characteristics by pour point depressant.