• Title/Summary/Keyword: Fire frequency

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Arc Fault Circuit Interrupter Design for Electrical Fire Protection (전기화재 방지를 위한 아크고장전류 차단기 설계)

  • Ban, Gi-Jong;Kim, Lark-Kyo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.55 no.5
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    • pp.220-225
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    • 2006
  • Arc Fault Current is an electric discharge which is occurred in two opposite electrode. In this paper, AFCI(arc fault circuit interrupter) is designed for the interruption of arc fault current which is occurred in the local electric network. This arc is one of the main causes of electric fire. Arc fault in electrical network has the characteristics of low current, high impedance and high frequency. Conventional arc fault circuit interrupter does not have the arc current interrupt function. Hence, Arc current controller is designed for the interruption of arc fault current which has the modified arc characteristics.

An Improvement on the Self Diagnostic Characteristics of the Triple Quard Channel Infrared Flame Detector (삼파장 4채널 적외선식 불꽃감지기의 자가진단 성능 개선)

  • Song, Hyun Seon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.30 no.1
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    • pp.49-54
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    • 2016
  • There is needed the quard channel triple wave lengths pyroelectric infrared flame detector to recognize the unique characteristics of fire sources in various type. This system detects the triple wave lengths of infrared flame emitting maximum radient energy and scattering frequency of flame. The quard channel infrared flame detector detects the duplicate wave lengths of maximum radient energy to enhance the accuracy of detecting fire. Especially this paper focuss on development of the self diagnosis function system including contamination, temperature and input voltage. Therefore, the prevention and early suppression of fire is available.

Algorithm for Detection of Fire Smoke in a Video Based on Wavelet Energy Slope Fitting

  • Zhang, Yi;Wang, Haifeng;Fan, Xin
    • Journal of Information Processing Systems
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    • v.16 no.3
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    • pp.557-571
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    • 2020
  • The existing methods for detection of fire smoke in a video easily lead to misjudgment of cloud, fog and moving distractors, such as a moving person, a moving vehicle and other non-smoke moving objects. Therefore, an algorithm for detection of fire smoke in a video based on wavelet energy slope fitting is proposed in this paper. The change in wavelet energy of the moving target foreground is used as the basis, and a time window of 40 continuous frames is set to fit the wavelet energy slope of the suspected area in every 20 frames, thus establishing a wavelet-energy-based smoke judgment criterion. The experimental data show that the algorithm described in this paper not only can detect smoke more quickly and more accurately, but also can effectively avoid the distraction of cloud, fog and moving object and prevent false alarm.

The Study of Correlation between Pattern Identification of Stroke Patients and Meteorological Elements (중풍 환자 변증과 기후 요소와의 상관성에 관한 연구)

  • Ma, Mi-Jin;Han, Chang-Ho
    • The Journal of Internal Korean Medicine
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    • v.30 no.1
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    • pp.200-211
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    • 2009
  • There are many reports about correlations between meteorological elements and stroke. In Oriental medicine, it is recognized that the weather affects the human body and diseases, but there are few studies about the correlation between meteorological elements and pattern identification of stroke. 105 stroke patients classified into fire-heat pattern or dampress-phlegm pattern were registered during the study period. We took the measurement of each meteorological element (atmospheric pressure, temperature, humidity, wind speed) according to pattern identification and analyzed pattern identification into two groups according to mean of each meteorological element during the study period. Mean temperature was higher with the heat-fire pattern than with the dampness-phlegm pattern. Heat-fire pattern also had higher frequency when temperature was higher than mean temperature. There was no correlation between atmospheric pressure, relative humidity, or wind speed and pattern identification.

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Fire Safety Assessment Based on FSA and Risk Reduction of Machinery System Considering Functional Safety (기능적 안전을 고려한 FSA기반 기관 구역 화재 안전성 평가 및 개선)

  • Suh, Sung-Won;Yang, Young-Soon;Chung, So-Yeon;Ryu, Won-Sun
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.3
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    • pp.239-246
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    • 2012
  • It is the well-known fact that most part of goods transported are moved on the unfavorable ocean and even a small amount of accident on sea is extremely dangerous for human lives, financial losses, and social responsibility. Among the several causes of accidents, those by fire have occurred frequently and their damage has been highly serious. The aim of this paper is to assess the risk of fires due to oil leakage in the machinery space. To define the possible fire scenario, our team has performed the search of casualty database and reviewed the previous and various studies in the field. As a result, it is noted that the quantitative risk of the fire scenario have been evaluated on the ground of the FSA risk model. The expected frequency of a fire amounts to incidents during the life of a ship, and the expected financial damage amounts to 5,654 USD per a ship. By adopting Safety Instrumented System (SIS) introduced in IEC 61508 and IEC 61511, SIS model is designed to prevent oil leakage fire as a risk reduction method. It is concluded that System Integrity Level (SIL) 1 seems to be appropriate level of SIS.

Review of Studies on Fire Needle (화침에 대한 국내외 연구 경향 고찰)

  • Moon, Su-Jeong;Kong, Jae-Cheol;Jo, Dong-Chan;Kim, Esther;Song, Young-Sun;Lee, Jung-Han
    • Journal of Korean Medicine Rehabilitation
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    • v.21 no.4
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    • pp.67-76
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    • 2011
  • Objectives: The aim of this review was to investigate studies on fire needle and to propose for the better method of studies in the future. Methods: Studies related to fire needle were searched with electric database for this study, and 10 domestic and overseas databases were included. Results: 19 clinical studies were analyzed in terms of condition, time of heating, number and frequency of treatment, number of heating, safety procedure or device aid reports of adverse events. Also 3 review studies were summarized. The number of studies was increasing and the kind of diseases to treat with fire noodle were various. Especially musculoskeletal diseases like ligament lesion and lumbago were noticeable. Heating-after-insertion method was recently proposed but the use of term was confusing. The report of adverse events or safety procedure was rare. Also there was an effort to develop more convenient and safer device. Conclusions: High quality clinical trial en fire needle is needed especially to compare 2 methods, heating-after-insertion and heating-before-insertion. And studies need to report safety procedures and adverse events to evaluate the safety of fire needle therapy.

Regional Characteristics Model to Explain Fire Damage Elements : Hypotheses and Verification (지역 유형별 화재 피해 특성변수 모델: 가설과 검증)

  • Kang, Byungki;Chang, Eunmi;Choi, Kapyong
    • Journal of the Korean association of regional geographers
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    • v.21 no.2
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    • pp.379-393
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    • 2015
  • The fire damage has been increased as the frequency of fire incidence decreases with increasing in death and economic loss. Local governments are dependent on the activities of fire-fighters with crude preparedness and prevention for fire incidence. Most of researches on fire safety have focused on descriptive statistics which show general trends in fire incidence and condition. Here we tried to make a mutual causal model for fire damage, to make three big hypotheses with laying three small hypotheses under each big hypothesis. Five years statistics from public domains in the form of hardcopy or softcopy were collected and fifteen independent variables were selected to explain the number of death, the number of fire incidence and the amount of economic loss from fire incidence. The significances of statistics are different among the regional characteristics. The hypotheses were partially rejected and the meanings of rejected factors will refresh the tentative prejudice. It is necessary to revise the principle that the number of population and size of area are regarded as the most important criteria to allocate resources for fire control and to have the criteria flexible with results of our research such as the number of the weak to fire disaster.

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Effects of Flow Excitation on the Nitrogen Oxide Emission of a Non-Premixed Flame (유동장 자극이 화염의 질소산화물 배출에 미치는 영향)

  • 이기만
    • Fire Science and Engineering
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    • v.18 no.2
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    • pp.34-40
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    • 2004
  • The effects of external flow excitation with various frequencies and amplitudes on the flame behavior and pollution emission characteristics from a laminar jet flame are experimentally investigated. Measurements of $NO_x$ emission indices ($EINO_x$), performed in vertical lifted flame like turbulent with various exciting amplitude at a constant resonance frequency, have been conducted. It was also conducted to investigate the effects of excited frequency at a constant exciting amplitude on $NO_x$ emissions with a various frequency ranged 0 Hz to 2 KHz. From the vertical lifted turbulent flame of the excited jet with resonance frequency by strong excitation was shown that the dependence of $NO_x$ emission could be categorized into three groups Group I of long flame length with high disturbances yielding high $NO_x$ emission, Group II of intermediate flame length and relative narrow flame volume with low disturbance yielding low $NO_x$ emission and Group III of long flame length and large flame volume with high time & space disturbances behaviour yielding high $NO_x$ emission.

A Study on the Magneto-Thermal Analysis of Induction Heating Jar according to Input Frequency Variation (입력주파수 변화에 따른 유도가열조리기의 자계-열계 해석에 관한 연구)

  • Oh, Hong-Seok
    • Journal of the Korean Society of Industry Convergence
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    • v.5 no.3
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    • pp.233-238
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    • 2002
  • 본 논문에서는 유도가열조리기의 효과적인 설계를 위하여 입력주파수 변화에 따른 유도가열조리기의 자계와 열계 해석 방법을 제시하였다. 유도가열조리기의 내부자계는 3차원 축대칭 유한요소법을 사용하여 해석하였으며, 열원은 유도가열조리기의 내부에서 유도된 와전류에 의하여 발생되고, 열은 열원과 열방정식을 사용하여 계산되어진다. 또한, 유도가열조리기의 온도특성을 스테인레스와 알루미늄 각각에 대하여 주파수와 투자율에 따라 제시하였다.

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Simulation of the Brownian Coagulation of Smoke Agglomerates in the Entire Size Regime using a Nodal Method (결절법을 이용한 전영역에서의 연기입자 응집체에 대한 브라운응집현상 해석)

  • Goo, Jae-Hark
    • Journal of Korean Society for Atmospheric Environment
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    • v.27 no.6
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    • pp.681-691
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    • 2011
  • The size distributions of smoke particles from fire are prerequisite for the studies on fire detection and adverse health effects. Above the flame of the fire, coagulation dominates and the smoke particles grow from 1 to 50 nm up to 100 to 3,000 nm, sizes ranging from the free-molecular regime to the continuum regime. The characteristics of the agglomeration of the smoke particles are well known, independently for each of the free-molecular and continuum regimes. However, there are not many systematic studies in the entire regime by the complexity of the mechanisms. The purpose of this work is to find the characteristics of the development of the size distribution of smoke particles by agglomeration in the entire size range covering the free-molecular regime, via transition regime, to the near-continuum and continuum regime for each variation of parameters such as fractal dimension, primary particle size and dimensionless coagulation time. In this work, the dynamic equation for the discrete-size spectrum of the particles was solved using a nodal method based on the modification of a sectional method. In the calculation, the collision frequency function for the entire regime, which is derived by using the concept of collision volume and general enhancement function, was applied. The self-preserving size distribution for the entire regime is compared with the ones for the free-molecular or continuum regimes for each variation of the parameters.