• Title/Summary/Keyword: venting

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Gasdynamics of rapid and explosive decompressions of pressurized aircraft including active venting

  • Pagani, Alfonso;Carrer, Erasmo
    • Advances in aircraft and spacecraft science
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    • 제3권1호
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    • pp.77-93
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    • 2016
  • In this paper, a zero-dimensional mathematical formulation for rapid and explosive decompression analyses of pressurized aircraft is developed. Air flows between two compartments and between the damaged compartment and external ambient are modeled by assuming an adiabatic, reversible transformation. Both supercritical and subcritical decompressions are considered, and the attention focuses on intercompartment venting systems. In particular, passive and active vents are addressed, and mathematical models of both swinging and translational blowout panels are provided. A numerical procedure based on an explicit Euler integration scheme is also discussed for multi-compartment aircraft analysis. Various numerical solutions are presented, which highlight the importance of considering the opening dynamics of blowout panels. The comparisons with the results from the literature demonstrate the validity of the proposed methodology, which can be also applied, with no lack of accuracy, to the decompression analysis of spacecraft.

Control of accidental discharge of radioactive materials by filtered containment venting system: A review

  • Bal, Manisha;Jose, Remya Chinnamma;Meikap, B.C.
    • Nuclear Engineering and Technology
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    • 제51권4호
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    • pp.931-942
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    • 2019
  • Radioactive materials are released from the molten core into the containment at the time of a severe accident in a nuclear power plant (NPP). Filtered containment venting system is a popular and effective safety measure installed to obstruct the uncontrolled escape of radioactive materials due to the over pressurization of the containment. Different designs of filtered containment venting system (FCVS) are available today, each being the result of extensive research and development varying in one way or the other. This paper gives an elaborate description of the different types of FCVS currently being used, the current usage status in over 17 countries and the legislations regarding it. The recent researches being carried out in this field has also been discussed in detail. This present paper focuses on the critical review of existing FCVS, reports the challenges faced by it and highlights the potential developments to overcome the difficulties.

초고진공용 건조질소 통풍장치 (Dry Nitrogen Venting System for Ultra-high Vacuum)

  • 이성수;유선일;정진욱;정석민
    • 한국진공학회지
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    • 제1권3호
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    • pp.332-335
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    • 1992
  • 초고진공 시스템에 있어서 시스템을 대기압으로 바람을 넣은 후 정상상태로의 신 속한 원상회복을 위하여 건조질소 통풍(venting) 장치를 고안 제작하였다. 이 장치는 액체 질소 저장통, 증발기 및 여과기로 구성되어 있다. 이 장치에 의한 통풍효과와 다른 방법에 의한 통풍효과를 가스 방출률 측정을 통하여 정성적으로 비교 분석하였을 때, 본 장치가 가 장 낮은 가스 방출률과 가장 빠른 진공회복을 보여주었다.

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사회인구학적 변인, 가족의 정서적 환경, 어머니의 훈육방식 및 학령기 아동의 정서조절능력 (Socio-demographic Variables, Family Emotional Environment, Maternal Discipline Style, & School Children's Emotional Regulation)

  • 김혜경;김영희
    • 가정과삶의질연구
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    • 제27권3호
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    • pp.145-158
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    • 2009
  • The purpose of this study was to investigate the effects of socio-demographic variables, family emotional environment and maternal discipline style on school children's emotional regulation. Subjects of this study consisted 953 elementary school students drawn from 4 elementary schools in Cheong-ju city and Cheongwon-gun. Data were analyzed by the methods frequency, percentage, Cronbach's ${\alpha}$, factor analysis, Pearson's correlation, and hierarchical regression using SPSSWIN 12.0 program. The results of this study were as follows: First, girls used greater problem-focused coping than boys did. Children in sixth grade used more problem-focused coping regulation compared to those in fourth grade. When children perceived higher level of family communication, emotional support, participation of family rituals, family worries, and parental conflict, they were more likely to use problem-focused coping. Additionally, both maternal supportive discipline and behavioral controlling discipline styles increased children's problem-focused coping. Second, girls presented greater emotional venting than boys did. Children in sixth grade expressed higher level of emotional venting compared to those in fourth grade. While family communication, family worries, and parental conflict increased children's emotional venting, family emotional support and participation of family rituals decreased it. Only mothers' psychological controlling discipline positively predicted children's emotional venting. Third, girls presented higher level of children's aggressive expression than boys did. The lower level of family support increased children's aggressive expression. Higher level of family worries and parental conflict increased it as well. Also, children's aggressive expression was positively predicted by mothers' psychological controlling discipline. Fourth, girls presented greater avoidance than boys did. Children in sixth grade expressed higher level of emotional avoidance compared to those in fourth grade. In family emotional environment, while family support lowered children's emotional avoidance, family worries and parental conflict increased it. Moreover, mothers' psychological and behavioral controlling discipline styles positively explained children's emotional avoidance. In conclusion, family emotional environment was the strongest factor to predict school children's emotional regulation among other variables.

정신질환자들의 역기능적 태도, 스트레스 대처 방식 및 우울증상 간의 관계 (Relationship among Dysfunctional Attitudes, Stress Coping Strategies and Depressive Symptoms in Psychiatric Patients)

  • 박찬무;서경란;이민규
    • 정신신체의학
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    • 제5권1호
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    • pp.31-42
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    • 1997
  • This study was aimed to investigate dysfunctional attitudes, stress coping strategies and depressive symptoms in psychiatric patients. The subjects of this study consisted of 210 patients(138 schizophrenic patients, 29 depression patients, 43 alcohol dependence patients) according to DSM-IV criteria. Futhermore, the instruments were K-BDI(Beck Depression Inventory-Korean version), DAS(Dysfunctional Attitude Scale) and multidimensional coping strategy scale. The results were the following. 1) There were statistically significant correlations between depressive symptoms and dysfunctional attitudes in psychiatric patients. 2) In terms of coping strategies, there were positive correlations between depressive symptoms and focus on and venting emotions, accommodation, active forgetting, self-criticism, positive comparison, fatalism, passive withdrawal. Whereas, there was significant negative correlation between depressive symptom and active coping. 3) In terms of coping strategies, there were significant correlations between dysfunctional attitudes and focus on and venting emotions, active forgetting, self-criticism, positive comparison, fatalism, passive withdrawal. 4) Depression groups reported significantly higher BDI scores than schizophrenia groups. 5) In depression groups, DAS scores were significantly higher than those in schizophrenia groups. 6) In terms of coping strategies according to diagnosis, there were significant differences in venting emotions, active forgetting and self-criticism. As for venting emotions, alcoholic groups were scored significantly higher than schizophrenic groups. As for active forgetting, depression groups were scored significantly higher than schizophrenic groups. In self-criticism, depression groups and alcohol dependence groups reported significantly higher scores than schizophrenic groups.

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유아의 부정적 정서에 대한 부모의 반응유형, 유아의 대처반응 및 또래수용간의 관계 연구 (Relationships between Parent's Reactions to Preschoolers' Negative Emotions, Coping Styles and Peer Acceptance)

  • 강희연;강문희
    • 아동학회지
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    • 제20권3호
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    • pp.171-182
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    • 1999
  • This study examined the relations between parents' reactions to their preschool child's negative emotions, coping styles, and peer acceptance. Subjects were 250 5-year-old preschoolers and their parents. Instruments were the Coping with children's Negative Emotions Scale, and coding strategies checklist and peer rating scales for children. Data were analyzed with the SPSS PC + program. Parent's emotion-focused reactions, encouragement of expression and problem-focused reactions were positively associated with both peer acceptance and child coping styles whereas parent's distress, and punitive and minimizing reactions were associated with lower Peer acceptance and child coping styles of venting, denial, aggressive action, and avoidance. In child coping styles, problem solving was positively associated with peer acceptance while aggressive action anti venting were associated with a lower level of peer acceptance. Problem solving tended to be positively associated with peer acceptance, whereas aggressive action and venting tended to be associated with lower level of peer acceptance. (4) There was a statistically significant relations among parent's reactions to preschoolers' negative emotions, preschoolers' coping styles, and peer acceptance. There were the positive relations among parent's supportive reactions preschoolers' coping styles of problem solving and seeking support, and peer acceptance.

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HYLGS 모델을 활용한 수도권 매립지에서의 침출수-가스의 동시유동 해석에 관한 연구

  • 이광희;박용찬;성원모
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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    • pp.225-231
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    • 1998
  • Open dump causes groundwater and soil contamination by leachate, air pollution by LFG (Landfill Gas). In this paper, in order to improve landfill researches which have been done about reduction of high leachate level and LFG collection in the Kimpo landfill separately, the effect of simultaneous flowing of leachate and LFG has been Studied. The HYLGS (Hanyang Leachate Gas Simulator) used in this study is a 3D, 2-phase, transient FDM model which can be applied to venting trenches in a landfill. From present numerical analysis it can be concluded that all the pressures of the Kimpo landfill grid system are almost the same and their maximum value in the center grid block of the system is approximately 26 m $H_2O$ (2.52 atm), that because the pressures of venting trench layer situated in the middle of the landfill have the lowest values and equal with air pressure, the venting trenches play an important role in landfill stabilization, that the flow of gas will be more difficult as time goes by owing to the increase of LGR(Leachate and gas ratio).

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THERMAL HYDRAULIC ISSUES OF CONTAINMENT FILTERED VENTING SYSTEM FOR A LONG OPERATING TIME

  • Na, Young Su;Ha, Kwang Soon;Park, Rae-Joon;Park, Jong-Hwa;Cho, Song-Won
    • Nuclear Engineering and Technology
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    • 제46권6호
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    • pp.797-802
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    • 2014
  • This study investigated the thermal hydraulic issues in the Containment Filtered Venting System (CFVS) for a long operating time using the MELCOR computer code. The modeling of the CFVS, including the models for pool scrubbing and the filter, was added to the input file for the OPR-1000, and a Station Blackout (SBO) was chosen as an accident scenario. Although depressurization in the containment building as a primary objective of the CFVS was successful, the decontamination feature by scrubbing and filtering in the CFVS for a long operating time could fail by the continuous evaporation of the scrubbing solution. After the operation of the CFVS, the atmosphere temperature in the CFVS became slightly above the water saturation temperature owing to the release of an amount of steam with high temperature from the containment building to the scrubbing solution. Reduced pipe diameters at the inlet and outlet of the CFVS vessel mitigated the evaporation of scrubbing water by controlling the amount of high-temperature steam and the water saturation temperature.

고층건물 화재시 배연계획에 관한 연구 (A Study on the Smoke Venting Plan in the High-Rise Building Fires)

  • 김우영
    • 한국화재소방학회논문지
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    • 제3권1호
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    • pp.11-18
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    • 1989
  • The suffering damage of persons and properties from fires has become large sized in modem society that buildings are rapidly higher, denser and more complex. Especially, in the building fires, it is recently the most important issue that the treatment of smoke which is the hardest hindrance in escape. Therefore, as effective exhaust matter of smoke or poisonous gas is connected directly, synthetic, fundamental fire prevention countermeasure must be achieved after mutual connections between architecture and mechanical system and requlations ars sufficiently examinated. From this studies, 1 show the structure computation data which can be applied to smoke venting plan and architectural design for safety after find necessity and point at issue of prevention plan of fires by examinating statistical data about cause and damage situation.

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