• 제목/요약/키워드: Thermal response test

검색결과 235건 처리시간 0.027초

가변환경하의 불안정 시스템에 대한 자율적응 제어기 설계 (Design of Self-Adapted Controller for Unstable System in Variable Environment)

  • 김성희
    • 정보학연구
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    • 제5권4호
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    • pp.57-64
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    • 2002
  • 부품들에 대한 열반응 검증 시스템은 모델링이 없으므로 일반적으로 PID 알고리즘에 의해 제어된다. 그러나 이 알고리즘에 의한 제어는 적절한 제어에 있어서 많은 한계성을 지닌다. 이러한 문제를 해결하기 위해 시스템에 대한 자율 탐색기능을 갖는 퍼지 알고리즘에 기반 된 제어기를 설계한다. 퍼지 입력소속함수가 설정된 안정영역에 기반 되어 적응되고, 규칙기반이 시스템 반응에 기초되어 변환된다. 추론과 비퍼지화를 통해 계산된 출력값이 시스템 동작에 알맞은 값으로 변환된다. 이러한 조절을 통해 시스템이 불안정 영역으로 이동하는 것을 최소화시킨다.

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고체추진기관 둔감시험 평가 기법에 관한 연구 (A Study on Insensitive Munition Test and Evaluation for Solid Rocket Motor)

  • 이도형;김창기;이환규;유지창
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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    • pp.129-132
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    • 2010
  • 둔감추진기관 개발은 돌발적인 기폭 가능성과 이에 따른 막대한 피해를 최소화함으로써 사고로부터 인명과 장비의 생존성보장을 규정짓는데 중요한 목적이 있다. 열이나 기계적 충격으로 인한 격렬한 반응과 이어지는 반응의 확률을 최소로 줄이고 적재탄, 양산중이나 수송 저장중인 추진기관의 동조폭발로 주위환경에 치명적인 영향을 끼치는 격렬한 연쇄반응을 줄여야 한다. 이에 따라 반응형태도 과압, 파편비산, 열유속과 같은 결과에 평가의 기초를 두고 있다.

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Structural performance of unprotected concrete-filled steel hollow sections in fire: A review and meta-analysis of available test data

  • Rush, David;Bisby, Luke;Jowsey, Allan;Melandinos, Athan;Lane, Barbara
    • Steel and Composite Structures
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    • 제12권4호
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    • pp.325-350
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    • 2012
  • Concrete filled steel hollow structural sections (CFSs) are an efficient, sustainable, and attractive option for both ambient temperature and fire resistance design of columns in multi-storey buildings and are becoming increasingly common in modern construction practice around the world. Whilst the design of these sections at ambient temperatures is reasonably well understood, and models to predict the strength and failure modes of these elements at ambient temperatures correlate well with observations from tests, this appears not to be true in the case of fire resistant design. This paper reviews available data from furnace tests on CFS columns and assesses the statistical confidence in available fire resistance design models/approaches used in North America and Europe. This is done using a meta-analysis comparing the available experimental data from large-scale standard fire tests performed around the world against fire resistance predictions from design codes. It is shown that available design approaches carry a very large uncertainty of prediction, suggesting that they fail to properly account for fundamental aspects of the underlying thermal response and/or structural mechanics during fire. Current North American fire resistance design approaches for CFS columns are shown to be considerably less conservative, on average, than those used in Europe.

WDM용 광섬유 증폭기를 위한 전광섬유형 이득등화 필터 제작 (Design and Fabrication of Gain Equalization Filer in Optical WDM Systems Using Fiber Lattice Tapered Methods)

  • 장진현;전병구;김진식
    • 정보통신설비학회논문지
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    • 제8권2호
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    • pp.90-95
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    • 2009
  • All-optical fiber-type gain flattening filer (GFF) for an EDFA (Erbium doped fiber amplifier) were fabricated by using a FBT (fiber biconical tapered) process and the performance of the GFF was tested and athermal package was proposed. Historically, the chief contributor to gain unevenness has been the EDFA. Due to the inherent gain response of the EDFA's operation, there is always a modest imbalance in the gain applied as a function of wavelength. FBT methods have been used to make fiber type couplers and WDM filter since 1980. Attractivity of this methods was simple, cost effective and thermal stability. Simulation program tool is made to design target GFF profile for this paper. Fiber coupler manufacturing machine is modified for the GFF process. The final GFF is obtained by cascading 4 unit filter that has 6 taper stage. Test result shows 1 dB of wavelength flatness in the C band. Polarization dependent loss is under 0.15dB. The center wavelength variation is below ${\pm}$0.35nm at the temperature range of $20^{\circ}C$ to $70^{\circ}C$.

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마그네트론 스퍼터링법으로 제조된 ZnO/Cu/Al2O3 투명 면상 발열체 연구 (ZnO/Cu/Al2O3 transparent heaters fabricated by magnetron sputtering)

  • 민창흠;최두호
    • 한국표면공학회지
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    • 제55권5호
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    • pp.284-291
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    • 2022
  • Herein, we studied ultrathin Cu-layer-based transparent heaters embedded between a ZnO underlayer and an Al2O3 overlayer. The anti-reflecting functions for the ZnO and Al2O3 layers by independently varying the layer thicknesses, with the Cu layer thickness fixed at 8.5 nm. The smallest visible light transmittance of 11.1% was achieved when the overlayer and underlayer thicknesses were 90 and 30 nm, respectively. We conducted electrically driven Joule heating test for the Cu layers having thicknesses of 8.5 nm (Rs: 14.7 Ohm/sq.) and 19 nm (Rs: 3.4 Ohm/sq.). External voltages were increased with an interval of 2 V until irreversible failures occurred at temperatures of ~390 ℃ and 550 ℃, respectively. At each voltage increase before heater failures, the heater exhibited superior thermal response with the heater temperatures reaching over 90% of the final temperatures. The heaters also showed excellent reproducibility when turning on and off the heater repeatedly.

BEPU analysis of a CANDU LBLOCA RD-14M experiment using RELAP/SCDAPSIM

  • A.K. Trivedi;D.R. Novog
    • Nuclear Engineering and Technology
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    • 제55권4호
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    • pp.1448-1459
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    • 2023
  • A key element of the safety analysis is Loss of Coolant Analysis (LOCA) which must be performed using system thermal-hydraulic codes. These codes are extensively validated against separate effect and integral experiments. RELAP/SCDAPSIM is one such code that may be used to predict LBLOCA response in a CANDU reactor. The RD-14M experiment selected for the Best Estimate Plus Uncertainty study is a 44 mm (22.7%) inlet header break test with no Emergency Coolant Injection. This work has two objectives first is to simulate pipe break with RELAP and compare these results to those available from experiment and from comparable TRACE calculations. The second objective is to quantify uncertainty in the fuel element sheath (FES) temperature arising from model coefficient as well as input parameter uncertainties using Integrated Uncertainty Analysis package. RELAP calculated results are found to be in good agreement with those of TRACE and with those of experiments. The base case maximum FES temperature is 335.5 ℃ while that of 95% confidence 95th percentile is 407.41 ℃ for the first order Wilk's formula. The experimental measurements fall within the predicted band and the trends and sensitivities are similar to those reported for the TRACE code.

실물화재실험을 통한 공동주택의 화재안전성 연구 (The Real Scale Fire Test for Fire Safety in Apartment Housing)

  • 유용호;권오상;김흥열
    • 한국화재소방학회논문지
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    • 제23권5호
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    • pp.57-65
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    • 2009
  • 본 연구에서는 화재 시 많은 인명피해가 예상되는 공동 주택을 대상으로 단위공간별 화재 성상을 예측하기 위한 실물화재실험을 실시하였다. 실험 모델 주택을 구성하고 있는 내부 가연물을 선정한 후 각 단위 품목에 대한 화재특성 실험을 실시하였으며, 주방, 거실, 침실, 공부방 등 4종류의 단위 공간으로 구분하여 각각 실물화재실험을 실시하였다. 실험결과 침실의 경우 점화 후 약 5분이 경과되었을 때 플래쉬오버 상태에 이르게 되어 매우 급격한 성장을 보였으며, 최대 열방출율 약 7,433.3kW, 최대 CO 578.6ppm, 최대 $CO_2$ 1.25%, 내부 최대온도 $1,350^{\circ}C$로 측정되었다. 특히, 화재 발생 초기에 가연 공간에서 화재의 진화가 이루어지지 않으면 약 3분 내에 인체에 급격한 피해를 줄 수 있는 한계온도 이상으로 화재가 성장하기 때문에 신속한 초기 대응이 필요함을 확인하였으며, 장롱, 침구류 등 비교적 화재가 급속히 전이 될 수 있는 가연물량이 다수 배치되어 있는 침실에서 용도별 가연 공간 중 가장 위험도가 높은 것으로 측정되었다. 단위 가연물에서 발생되는 유독가스가 임계수준 이상으로 발생되어 이로 인해 인체에 심각한 피해를 줄 수 있을 것으로 판단된다. 이러한 실물화재실험에서 얻어낸 결과는 향후 화재확대 예측 시뮬레이션 결과와 비교함으로써 각 용도별 공간에서의 화재 확산 예측에 적용될 수 있을 것이다.

겨울철 잠옷이용실태와 구매시 평가기준 (Using and Evaluative Criteria for Purchasing of Sleepwear in Winter)

  • 권수애;최종명;김은영
    • 한국생활과학회지
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    • 제10권1호
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    • pp.101-111
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    • 2001
  • The purpose of this study was to investigate using and evaluative criteria for purchasing of sleepwear in winter. Subjects were 523 males and females aged from twenties to fifties, living in Chongju and Taejon. For data analysis, frequency, descriptive analysis, t-test, and F-test were used. The results are as follows. First, the ownership of sleepwear was sweat suits with zippered top, pajamas, T-shirts/pants, underwear, and nightgown in order. The mean of using sweat suits was used the highest, and subjects used more home wear than sleepwear in winter. Second, the using or sleepwear had a significant difference in cold-sensitiveness and body types. Cold-sensitive group used sweat suit and T-shirts/pants more than cold-insensitive group. Also, groups who are thin wore sweat suit the most while groups who are corpulent, used underwear the most when they slept. Third, subjects, who are married women and use bed, used nightgown, but pajamas were used by groups who are older, married, and professional. Sweat suits and T-shirts/pants were used the most by single aged twenties. Forth, consumers considered the wearing comfort when they purchased sleepwear for winter, and they evaluated washing/management, fabric, design/style, economic, service, brand, and others' response in order, for judging the quality of sleepwear. Also, the evaluative criteria had a significant difference in demographic variables such as sex, occupation, and marital state. These results implied that sleepwear would be needed for winter in terms of behavioral temperature regulation. Especially, cold-sensitive and thin group would wear knitted and two-piece sleepwear for thermal comfort when they sleep in winter. Also, Using and evaluative criteria of sleepwear would be different in demographic characteristics. For winter, sleepwear should be develop based on physiologic as well as demographic variables.

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Development and Ergonomic Evaluation of Spring and Autumn Working Clothes for Livestock Farming Workers

  • Kim, Insoo;Lee, Kyung-Suk;Seo, Min-Tea;Chae, Hye-Seon;Kim, Kyung-Su;Choi, Dong-Phil;Kim, Hyo-Cher
    • 대한인간공학회지
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    • 제35권5호
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    • pp.343-359
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    • 2016
  • Objective:In this study, we designed working clothes for livestock farmers to wear in spring and autumn to improve their work efficiency, conducted a physiological test on their performance, and evaluated their comfort. Background: In recent years, livestock farming in Korea has expanded, yet farmers' safety and sanitation levels remain low in hazardous environments that include organic dust, toxic gas, and heat stress, as well as the risk of accidents. Furthermore, most livestock farmers wear ordinary or dust-resistant clothes that are unsuitable for rearing livestock and compromise their safety and health. Thus, it is important to design specialized working clothes for livestock farmers that are comfortable and that minimize their health and safety risks. Method: To this end, we examined the literature on livestock (poultry, swine, and cattle) farmers' safety and sanitation issues, designed appropriate working clothes, and tested them in terms of sensory feel, physiological response, and subjective comfort. Results: The respondents expressed satisfaction with the new working clothes. The results of a physiological test showed a decline in temperature and humidity inside the clothes, a lower pulse rate, and a lower oxygen intake compared to the measurements taken when famers wore their previous working clothes. This indicates a fall in heat stress and fatigue, which was mostly consistent with the results of the assessment of subjective comfort. Conclusion: The results of the analysis show an improvement in the comfort of the new working clothes compared to the dust-resistant clothes that are widely worn. Based on this study, the new working clothes need to be further tested and evaluated to improve the design. Application: This study is expected to contribute to designing better working clothes for livestock farmers.

Economical Sweating Function in Africans: Quantitative Sudomotor Axon Reflex Test

  • Lee, Jeong-Beom;Bae, Jun-Sang;Choi, Jeong-Hwan;Ham, Joo-Hyun;Min, Young-Ki;Yang, Hun-Mo;Kazuhiro, Shimizu;Matsumoto, Takaaki
    • The Korean Journal of Physiology and Pharmacology
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    • 제8권1호
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    • pp.21-25
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    • 2004
  • People in tropics have the ability to tolerate heat by residential permanence in the tropics. Previously, we have shown that African and Thai subjects who lived for whole their lives in only their respective countries sweat less under hot conditions than South Koreans who also lived whole their lives in Korea. The difference in sweating responses was attributed to the dissimilar central and peripheral sweating mechanisms operating in people from both groups. In the present study, acetylcholine (ACh), the primary transmitter for the sudomotor functions, was iontophoretically administered to South Koreans and Africans to determine the characteristic sudorific responses of their acclimatized biologic make-up to their respective environments. Using quantitative sudomotor axon reflex test (QSART), direct (DIR) and axon reflex (AXR) responses were evaluated. The findings revealed that the sweat onset-time among South Koreans was 0.91 min earlier than among Africans (P<0.01). The axon reflex sweat volume of nicotine receptor activity AXR(1) and sweat volume of muscarinic receptor activity DIR(2) among South Koreans were 79% and 53% greater (P<0.01), respectively. These results indicate that the reduced thermal sweating among Africans is at least in part attributed to the diminished sensitivity of sweat glands to ACh.