• 제목/요약/키워드: fire control system

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설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제27권7호
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

원자력발전소 정지저출력 운전 기간의 물리적방호를 위한 핵심구역파악 (Vital Area Identification for the Physical Protection of Nuclear Power Plants during Low Power and Shutdown Operation)

  • 곽명웅;정우식;이정호;백민
    • 한국안전학회지
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    • 제35권1호
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    • pp.107-115
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    • 2020
  • This paper introduces the first vital area identification (VAI) process for the physical protection of nuclear power plants (NPPs) during low power and shutdown (LPSD) operation. This LPSD VAI is based on the 3rd generation VAI method which very efficiently utilizes probabilistic safety assessment (PSA) event trees (ETs). This LPSD VAI process was implemented to the virtual NPP during LPSD operation in this study. Korea Atomic Energy Research Institute (KAERI) had developed the 2nd generation full power VAI method that utilizes whole internal and external (fire and flooding) PSA results of NPPs during full power operation. In order to minimize the huge burden of the 2nd generation full power VAI method, the 3rd generation full power VAI method was developed, which utilizes ETs and minimal PSA fault trees instead of using the whole PSA fault tree. In the 3rd generation full power VAI method, (1) PSA ETs are analyzed, (2) minimal mitigation systems for avoiding core damage are selected from ETs by calculating system-level target sets and prevention sets, (3) relatively small sabotage fault tree that has the systems in the shortest system-level prevention set is composed, (4) room-level target sets and prevention sets are calculated from this small sabotage fault tree, and (5) the rooms in the shortest prevention set are defined as vital areas that should be protected. Currently, the 3rd generation full power VAI method is being employed for the VAI of Korean NPPs. This study is the first development and application of the 3rd generation VAI method to the LPSD VAI of NPP. For the LPSD VAI, (1) many LPSD ETs are classified into a few representative LPSD ETs based on the functional similarity of accident scenarios, (2) a few representative LPSD ETs are simplified with some VAI rules, and then (3) the 3rd generation VAI is performed as mentioned in the previous paragraph. It is well known that the shortest room-level prevention sets that are calculated by the 2nd and 3rd generation VAI methods are identical.

극상근 건병증의 한의학적 치료에 대한 연구 동향: 체계적 문헌 고찰과 메타 분석 (The Effect of Oriental Medicine Treatments for Supraspinatus Tendinopathy: Systematic Review and Meta-Analysis)

  • 강동협;이도훈;유상준;양석규;손자연;정설;김혜주;권민진;권오빈;장선우;조현우
    • 한방재활의학과학회지
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    • 제33권4호
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    • pp.45-59
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    • 2023
  • Objectives The aim of this study was to analyze the trends of researches on oriental medicine treatments for supraspinatus tendinopathy. Methods We used five databases for searching researches; Korean studies Information Service System, Oriental Medicine Advanced Searching Integrated System, Research Information Sharing Service, PubMed, and China National Knowledge Infrastructure. Only randomized controlled trials suitable for the subject were selected. The methodological quality of included randomized controlled trials (RCTs) was assessed by the Cochrane risk of bias tool. Results Twenty randomized controlled trials were analyzed. There were 9 types of treatment interventions; acupuncture, acupotomy, pharmacopuncture, electroacupuncture, fire needling, warming needle, catgut-embedding therapy, herbal medicine, cupping. The most frequently used treatment intervention was acupuncture and acupotomy. There were 9 outcome measurements including visual analog scale (VAS), Constant-Murley Score (CMS), and range of motion. The most used measurement was VAS. As a result of meta-analysis, acupuncture was more effective than control group in VAS. Additionally, acupotomy was clinically significant compared to control groups in VAS and CMS. Conclusions In this review, we analyzed researches on effectiveness of oriental medicine for supraspinatus tendinopathy. A provisional conclusion can be produced that acupuncture and acupotomy showed beneficial effect to supraspinatus tendinopathy. Although there were some RCT studies, many of them had a high risk of bias, so it is hard to conclude that our study can include overall clinical status. Further well-designed trials are needed.

Coilgun 성능향상을 위한 솔레노이드 코일 설계 (Parameter Study on the Design of Solenoid to Enhance the Velocity of Coilgun)

  • 장재환;김진호;이수정
    • 한국자기학회지
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    • 제25권3호
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    • pp.87-91
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    • 2015
  • 본 논문에서는 코일건 발사 시스템의 성능 향상을 위한 솔레노이드 설계에 대해 연구하였다. 즉, 코일건 솔레노이드의 코일 직경에 따른 피투사체의 발사속도에 대한 분석을 수행하였다. 코일건은 자기력을 이용하여 피투사체를 발사시키는 시스템이다. 솔레노이드에 순간적으로 큰 전류를 흘려주면 코일 주위에 순간적인 자기장이 만들어지고, 발사체는 플레밍의 오른손 법칙에 따라 코일의 중심 방향으로 자기력을 받아 발사된다. 피투사체의 발사 속도는 솔레노이드 코일이 생성하는 자기력과 비례한다. 하지만, 솔레노이드 코일은 규격에 따른 최대허용 전류가 존재한다. 따라서, 한계 전류 내에서 피투사체에 작용하는 자기력이 최대가 되는 솔레노이드 코일의 설계가 필요하다. 본 논문에서는 솔레노이드 코일의 설계를 위해 AWG(American Wire Gauge)6부터 AWG18까지의 코일의 직경에 따른 최적의 권수를 찾아서 발사가능여부와 그에 따른 발사속도를 비교 분석한다.

지상형 탄약고의 내부온도 감소 방안 연구 (A Study on the Deduction of Internal Temperature of the Ground Magazine)

  • 박형주;최명진;양재경
    • 산업경영시스템학회지
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    • 제36권3호
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    • pp.142-149
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    • 2013
  • Among ammunitions which are stored in a war field, the lifespan of propelling gunpowder is affected by storage environment such as storage temperature, humidity, and exposure to sunlight. These are because Nitrocellulose (NC) which is the main component of propelling gunpowder can be naturally disassembled to unstable substances similar with other nitric acid ester. We can't prevent it fundamentally from being disassembled, but to restrain induction of automatic disassembly by decomposition product, a decomposition product ($NO_2$, $NO_3$, and $HNO_3$) and tranquillizer DPA (Diphenylamine), having high reactivity, are added into a propellant. For this, it will decrease the velocity of tranquillizer which can also affect the velocity of producing the decomposition product of NC, storage temperature or humidity of propelling gunpowder is higher, drop of tranquillizer content is much faster. Therefore, to extend storage lifespan of propelling gunpowder, it is really important to control storage temperature or humidity inside the magazine. Hereupon, according to the manufacture of small scale model magazine and the result of performing experiments and measuring variation of inside temperature (storage temperature), using roof types that have a steel slate structure of magazine among ground magazines, this research shows the differences in details.

연구 실험실 사고의 근본원인분석 Map 개발에 관한 연구 (A Study on Development of Root Cause Analysis Map In Laboratory)

  • 엄석화;이수경
    • 한국가스학회지
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    • 제14권4호
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    • pp.6-11
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    • 2010
  • 연구실험실 사고 방지를 위하여 2005년 연구실 안전환경조성에 관한 법률이 법제화되어 국내 대학 또는 국공립출연연구소나 기업부설 연구소 실험실에서는 안전관리시스템을 구축하고, 안전점검과 정밀안전진단을 실시하고 있음에도 불구하고 폭발, 화재 등 각종 대형 사고가 지속적으로 발생하여 연구 활동 종사자의 인명 피해와 재산 손실이 상당한 수준에 이르고 있다. 또한 연구실험실에서 발생하는 사고는 유사한 내용으로 반복적으로 발생되고 있으므로 이러한 사고의 원인분석과 재발 방지를 위한 안전관리 대책이 시급하다. 따라서 본 논문에서는 국내 해외 대학 또는 국공립출연 연구소나 기업 부설 연구소 실험실에서 발생한 사건 사고에 대해 Root Cause Analysis 기법을 이용하여 사고원인 조사 결과를 보여주고, 이에 따른 실험실 사고원인 조사 분류 Map과 개선사항을 제시하여 연구실험실의 안전관리를 향상시키고자 한다.

터널굴착에서 다단식 발파기에 의한 전단면 발파의 적용성 연구 (Application of Full-Face Round by Sequential Blasting Machine in Tunnel Excavation)

  • 조영동;이상은;임한욱
    • 터널과지하공간
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    • 제4권2호
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    • pp.132-143
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    • 1994
  • Many methods and techniques to reduce ground vibrations are well known. Some of them are to adopt electric millisecond detonators with a sequential blasting machine or an initiating system with an adequate number of delay intervals. The types of electric detonators manufactured in korea include instantaneous, decisecond and millisecond delays but numbers of delay intervals are only limited from No.1 to No.20 respectively. It is not sufficient to control accurately millisecond time with these detonators in tunnel excavation. Sequential fire time refers to adding an external time delay to a detonators norminal firing time to obtain sequential initiation and it is determined by sequential timer setting. To reduce the vibration level, sequential blasting machine(S.B.M) with decisecond detonators was adopted. A total of 134 blasts was recorede at various sites. Blast-to-structure distances ranged from 20.3 to 42.0 meter, where charge weight varied from 0.24 to 0.75 kg per delay. The results can be summarized as follow: 1. The effects of sequential blasting machine on the vibration level are discussed. The vibration level by S.B.M are decreased approximately 14.38~18.05% compare to level of conventional blasting and cycle time per round can be saved. 2. The empirical equations of particle velocity were obtained in S.B.M and conventional blasting. V=K(D/W1/3)-n, where the values for n and k are estimated to be 1.665 to 1.710 and 93.59 to 137 respectively. 3. The growth of cracks due to vibrations are found but the level fall to within allowable value.

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삼음삼양(三陰三陽)의 종화규율(從化規律)에 관한 연구(硏究) (A Research on the rule of following of three ${\breve{U}}m$ and three Yan)

  • 김호현
    • 동의생리학회지
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    • 제14권2호통권20호
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    • pp.99-116
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    • 1999
  • This study was undertaken to define the expression rule of six vital substances for human life(六氣) in Meridians and the rule of following of three ${\breve{U}}m$ and three Yan. In order to investigate the expression rule of six vital substances for human life(六氣), incident(標)-fundamental(本) and Ki of middle energizer(中氣) of three ${\breve{U}}m$ and three Yang(三陰三陽) were reviewed. 1, The rule of following is formed centering around fundamental Ki(本氣) between incident(標) and fundamental(本). And in case the ${\breve{U}}m$ and Yang (陰陽) disposition of incident(標) and fundamental(本) is different, whether the ${\breve{U}}m$ and Yang(陰陽) disposition of incident(標) and fundamental(本) is same as those of Ki of middle energizer(中氣), is the key point in following fundamental and activating of the vital energy(氣化). 2. As twelve channels(十二經脈) have not only fundamental Ki(本氣) but also Ki of middle energizer(中氣) at the same time, in expression of six vital substances for human life(六氣), if the fundamental Ki(本氣) is stronger, fundamental Ki(本氣) can be expressed or if the fundamental Ki(本氣) is weaker, Ki of middle energizer(中氣) can be expressed. 3. Twelve channels which is connected with each other through the relation of the interior and the exterior can be regarded as a system, in which Wind(風) and Fire(火), Dryness(燥) and Dampness(濕), Cold(寒) and Heat(熱) maintain balance through mutual control. 4. We can see that in the disease caused by the unbalance of six vital substances for human life(六氣), expression of six pathogenic factor and controlment of six vital substances for human life(六氣) are made up after the following one in the rule of following(從化規律).

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직렬아크신호지 검출방법 (Detection Method of Series Arc Signal)

  • 길경석;지홍근;박대원;김일권;류길수;송재용
    • 한국철도학회논문집
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    • 제11권5호
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    • pp.477-481
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    • 2008
  • 본 논문은 저압계통에서 전기화재의 징후인 직렬아크의 검출방법에 대해 기술하였다. 제안한 검출회로는 전원주파수 성분을 80dB 이상 감소시킬 수 있는 저역차단주파수가 3kHz인 고역통과필터와 아크신호만을 검출하기 위한 중심주파수가 4kHz인 대역통과필터로 구성된다. UL1699에 규정된 아크발생장치를 이용하여 비선형부하인 위상제어 백열전구와 고주파발생부하인 인버터 추동 유도전동기에서 직렬아크신호를 모의하여 성능을 평가하였다. 실험 결과로부터 세안한 방식은 비선형부하와 고주파발생하에 대해서도 직렬아크신호를 정확히 구분함으로써 현재 최대 문제인 검출오류를 해결하였음이 확인되었다.

Dynamic quantitative risk assessment of accidents induced by leakage on offshore platforms using DEMATEL-BN

  • Meng, Xiangkun;Chen, Guoming;Zhu, Gaogeng;Zhu, Yuan
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제11권1호
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    • pp.22-32
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    • 2019
  • On offshore platforms, oil and gas leaks are apt to be the initial events of major accidents that may result in significant loss of life and property damage. To prevent accidents induced by leakage, it is vital to perform a case-specific and accurate risk assessment. This paper presents an integrated method of Ddynamic Qquantitative Rrisk Aassessment (DQRA)-using the Decision Making Trial and Evaluation Laboratory (DEMATEL)-Bayesian Network (BN)-for evaluation of the system vulnerabilities and prediction of the occurrence probabilities of accidents induced by leakage. In the method, three-level indicators are established to identify factors, events, and subsystems that may lead to leakage, fire, and explosion. The critical indicators that directly influence the evolution of risk are identified using DEMATEL. Then, a sequential model is developed to describe the escalation of initial events using an Event Tree (ET), which is converted into a BN to calculate the posterior probabilities of indicators. Using the newly introduced accident precursor data, the failure probabilities of safety barriers and basic factors, and the occurrence probabilities of different consequences can be updated using the BN. The proposed method overcomes the limitations of traditional methods that cannot effectively utilize the operational data of platforms. This work shows trends of accident risks over time and provides useful information for risk control of floating marine platforms.