• Title/Summary/Keyword: Fire control system

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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 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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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.

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

  • Kwak, Myung Woong;Jung, Woo Sik;Lee, Jeong-ho;Baek, Min
    • Journal of the Korean Society of Safety
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    • v.35 no.1
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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.

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

  • Dong-Hyeob Kang;Do-Hoon Lee;Sang-Joon Yoo;Seok-Gyu Yang;Ja-Yean Son;Seol Jung;Hea-Ju Kim;Minjin Kwon;Oh-Bin Kwon;Seon-Woo Jang;Hyun-Woo Cho
    • Journal of Korean Medicine Rehabilitation
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    • v.33 no.4
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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.

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

  • Jang, Jae-hwan;Kim, Jin-ho;Lee, Su-jeong
    • Journal of the Korean Magnetics Society
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    • v.25 no.3
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    • pp.87-91
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    • 2015
  • This paper reports the design of solenoid in a coilgun for high velocity of projectile in a coilgun system, according to diameter of coil. Coilgun using a magnetic force means a mechanism that can control the magnetic material. When momentarily supply a large current to the solenoid instantaneous magnetic field is created around the coil, the projectile is fired by receiving a magnetic force towards the center of the coil, based on the right-hand rule of Fleming. The velocity of projectile is proportional to the magnetic force generated by the electromagnetic coil. The current affects the life of the coil and the current limit exists. Therefore, the coilgun design, which does not exceed the current limit and the magnetic forces are at the maximum, is required. In this paper, whether it is possible fire looking for the optimal number of turns according to the diameter of the coil from AWG #6 to AWG #18 for the design of the solenoid coil, and comparative analysis firing rate associated with it.

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

  • Park, Hyungju;Choi, Myoungjin;Yang, Jaekyung
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.36 no.3
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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.

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

  • Eom, Seok-Hwa;Lee, Su-Kyung
    • Journal of the Korean Institute of Gas
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    • v.14 no.4
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    • pp.6-11
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    • 2010
  • The continuous fatal accidents like explosion or fire cause huge losses of both life and property in laboratories even though safety management system has been built and periodical checkups and safety diagnosis have been implementing in universities and enterprise-affiliated research institutes since Act on the Establishment of Safe Laboratory Environment was enacted in 2005 to prevent accidents in research laboratories. Cause analysis and safety management measures to prevent recurrence of accidents are urgently needed because accidents in research laboratories occur repeatedly with similar contents. This study will show results of analysis on incidents and accidents occurred in laboratories in universities and enterprise-affiliated research institutes using Root Cause Analysis Method and propose classified map of cause investigation and improvements so as to improve safety management in research laboratories.

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

  • 조영동;이상은;임한욱
    • Tunnel and Underground Space
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    • v.4 no.2
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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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A Research on the rule of following of three ${\breve{U}}m$ and three Yan (삼음삼양(三陰三陽)의 종화규율(從化規律)에 관한 연구(硏究))

  • Kim, Ho-Hyun
    • Journal of Oriental Physiology
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    • v.14 no.2 s.20
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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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Detection Method of Series Arc Signal (직렬아크신호지 검출방법)

  • Kil, Gyung-Suk;Ji, Hong-Keun;Park, Dae-Won;Kim, Il-Kwon;Rhyu, Keel-Soo;Song, Jae-Yong
    • Journal of the Korean Society for Railway
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    • v.11 no.5
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    • pp.477-481
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    • 2008
  • This paper dealt with a detection method of series arc existence which is a symptom of electric fires in low-voltage system. The proposed detection circuit consists of a high-pass filter with a low cut-off frequency of 3kHz to attenuate power frequency voltage by 80 dB and an active band-pass filter with a center frequency of 4kHz to detect only the series arc signals. The performance of the circuit was evaluated in a phase-controlled incandescent lamp as a non-linear load and an inverted-fed induction motor as a high frequency load by using the arc generator specified in UL1699. From the experimental results, it was confirmed that the proposed method solved the detection error, which is being the most problem, by discriminating the series arc signal even in non-linear and high frequency loads.

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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    • v.11 no.1
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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.