• Title/Summary/Keyword: fire loads

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Recommended Practice on the Precautinary System and Installation to prevent electrical fire from reoccurring in underground tunnel (지하구조물내 전기재해 방지를 위한 설치지침 및 예방시스템 구축)

  • Kim, Se-Dong;Kim, Young-Jin;Kang, Jae-Mo
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2005.05a
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    • pp.337-341
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    • 2005
  • Most utiltity systems are subject to frequent changes, often due to increased loads and demand to up-grade quality of service provided. Urban renewal, expressway construction and suburban growth have also caused significant changes in urban utility distribution systems. Recently, it is required that a guideline for planning of a complete system, the reasonable design and construction methods for the efficient installation common utility tunnels must be estabilished. It prompts drastic measures to guard cities and their inhabitants against the horror of massive fires in the future. Preparedness holds the key to safety.

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An Experimental Study on the Strength Development of Rubber Mortar (Rubber Mortar의 강도성상에 관한 실험적 연구)

  • 손종규;김재욱;임유묵;정환욱;문장수;정상진
    • Proceedings of the Korea Concrete Institute Conference
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    • 1996.04a
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    • pp.30-35
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    • 1996
  • Accumulations of worn-out automobile tires creat fire and health hazards. As a possible solution to the problem of scrap-tire disposal, an experimental study was conducted to examine the potential of using tire chips as aggregate in rubber mortar. This paper examines strength and toughness properties of rubber mortar in which different amounts of rubber-tire particles of several sizes were used as aggregate. The rubber mortar mixtures exhibited lower compressive, bending, tensile than did normal mortar. However, these mixtures did not demonstrate brittle failure, but rather a ductile, plastic failure, and had the ability to absorb a large amount of plastic energy under compressive loads.

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A Study on the Development of High Strength Railroad Block Using Wasted Tire Chips (Rubber Concrete를 사용한 고강도 철도침목의 실용화 연구)

  • 손종규;임유묵;정환욱;문장수;정상진;최문식
    • Proceedings of the Korea Concrete Institute Conference
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    • 1996.10a
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    • pp.44-50
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    • 1996
  • Accumulation of worn-out automobile tires creat fire and health hazards. As a possible solution to the problem of scrap-tire disposal, an experimental study was conducted to examine the potential of using tire chips as aggregate in Railroad block. This paper examines strength and toughness properties of Railroad block in which different amounts of rubber-tire particles of several sizes were used as aggregate. The Railroad block mixtures exhibited lower compressive, bending than did normal block. However, these mixtures did not demonstrate brittle failure, but rather a ductile, plastic failure, and had the ability to absorb a large amount of plastic energy under compressive loads.

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Development of the Cabinet Panel of Real-Time Availability Checks for Electrical Disaster Decreasing at Traditional Markets (재래시장 전기재해 감소를 위한 실시간 확인이 가능한 분전반 개발)

  • Kim, Gi-Hyun;Lee, Sang-Ick;Shin, Seong-Su;Bae, Seok-Myung
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.3
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    • pp.335-339
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    • 2010
  • In this paper, in order to reduce the electrical disaster damage which is caused by with electrical equipment of traditional markets, we developed the cabinet panel and the electrical safety monitoring system which is able to monitor the electrical equipments condition(over current, leakage current, arc, WH, electrical fire factor etc.) at traditional markets. We constructed Test-bed for testing reliability of electrical safety monitoring system and cabinet panel. And we tested the cabinet for over current, leakage current and arc under the traditional markets actual condition. This paper will be used with the data for an demonstration project after compensating the defects which are occurred to operation of traditional markets actual loads.

A study on the precautinary measures to prevent electrical fire from reoccurring in underground tunnel (공동구내 전기화재 미연 방지를 위한 예방시스템 구축 사례 고찰)

  • Kim, Se-Dong
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.05a
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    • pp.429-433
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    • 2004
  • Most utiltity systems are subject to frequent changes, often due to increased loads and demand to up-grade quality of service provided. Urban renewal, expressway construction and suburban growth have also caused significant changes in urban utility distribution systems. Recently, it is required that a guideline for planning of a complete system, the reasonable design and construction methods for the efficient installation common utility tunnels must be estabilished. It prompts drastic measures to guard cities and their inhabitants against the horror of massive fires in the future. Preparedness holds the key to safety.

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A Finite Element Analysis on Cylinder Liner Deformation of a Diesel Engine (디젤기관 실린더 라이너 변형에 대한 유한요소 해석)

  • Sangho Ahn
    • Journal of Auto-vehicle Safety Association
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    • v.6 no.1
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    • pp.33-40
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    • 2014
  • In this study the cylinder liner deformation which is one of the most influencing factors in a diesel engine oil consumption was performed by the finite element analysis on the basic designed structure consisting of the cylinder block, head and liners under the conditions of assembly, thermal and gas loads. Compared with a large number of other cylinder blocks showing remarkable harmonic orders of the liner distortion, results are excellent. Namely. the higher harmonic order amplitudes of the radial liner deformation amount to 1 ~ 2㎛ maximally. The main reason lies in the relatively large wall thickness of the liner which amounts to 8.2% of the bore diameter. Besides, a very stiff and symmetrical cylinder block design in combination with a bolt force introduction approximately 1.5mm below the block top deck have a further share on these results. Therefore excellent low oil consumption can be expected.

Comparison of Cognitive Loads between Koreans and Foreigners in the Reading Process

  • Im, Jung Nam;Min, Seung Nam;Cho, Sung Moon
    • Journal of the Ergonomics Society of Korea
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    • v.35 no.4
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    • pp.293-305
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    • 2016
  • Objective: This study aims to measure cognitive load levels by analyzing the EEG of Koreans and foreigners, when they read a Korean text with care selected by level from the grammar and vocabulary aspects, and compare the cognitive load levels through quantitative values. The study results can be utilized as basic data for more scientific approach, when Korean texts or books are developed, and an evaluation method is built, when the foreigners encounter them for learning or an assignment. Background: Based on 2014, the number of the foreign students studying in Korea was 84,801, and they increase annually. Most of them are from Asian region, and they come to Korea to enter a university or a graduate school in Korea. Because those foreign students aim to learn within Universities in Korea, they receive Korean education from their preparation for study in Korea. To enter a university in Korea, they must acquire grade 4 or higher level in the Test of Proficiency in Korean (TOPIK), or they need to complete a certain educational program at each university's affiliated language institution. In such a program, the learners of the Korean language receive Korean education based on texts, except speaking domain, and the comprehension of texts can determine their academic achievements in studying after they enter their desired schools (Jeon, 2004). However, many foreigners, who finish a language course for the short-term, and need to start university study, cannot properly catch up with university classes requiring expertise with the vocabulary and grammar levels learned during the language course. Therefore, reading education, centered on a strategy to understand university textbooks regarded as top level reading texts to the foreigners, is necessary (Kim and Shin, 2015). This study carried out an experiment from a perspective that quantitative data on the readers of the main player of reading education and teaching materials need to be secured to back up the need for reading education for university study learners, and scientifically approach educational design. Namely, this study grasped the difficulty level of reading through the measurement of cognitive loads indicated in the reading activity of each text by dividing the difficulty of a teaching material (book) into eight levels, and the main player of reading into Koreans and foreigners. Method: To identify cognitive loads indicated upon reading Korean texts with care by Koreans and foreigners, this study recruited 16 participants (eight Koreans and eight foreigners). The foreigners were limited to the language course students studying the intermediate level Korean course at university-affiliated language institutions within Seoul Metropolitan Area. To identify cognitive load, as they read a text by level selected from the Korean books (difficulty: eight levels) published by King Sejong Institute (Sejonghakdang.org), the EEG sensor was attached to the frontal love (Fz) and occipital lobe (Oz). After the experiment, this study carried out a questionnaire survey to measure subjective evaluation, and identified the comprehension and difficulty on grammar and words. To find out the effects on schema that may affect text comprehension, this study controlled the Korean texts, and measured EEG and subjective satisfaction. Results: To identify brain's cognitive load, beta band was extracted. As a result, interactions (Fz: p =0.48; Oz: p =0.00) were revealed according to Koreans and foreigners, and difficulty of the text. The cognitive loads of Koreans, the readers whose mother tongue is Korean, were lower in reading Korean texts than those of the foreigners, and the foreigners' cognitive loads became higher gradually according to the difficulty of the texts. From the text four, which is intermediate level in difficulty, remarkable differences started to appear in comparison of the Koreans and foreigners in the beginner's level text. In the subjective evaluation, interactions were revealed according to the Koreans and foreigners and text difficulty (p =0.00), and satisfaction was lower, as the difficulty of the text became higher. Conclusion: When there was background knowledge in reading, namely schema was formed, the comprehension and satisfaction of the texts were higher, although higher levels of vocabulary and grammar were included in the texts than those of the readers. In the case of a text in which the difficulty of grammar was felt high in the subjective evaluation, foreigners' cognitive loads were also high, which shows the result of the loads' going up higher in proportion to the increase of difficulty. This means that the grammar factor functions as a stress factor to the foreigners' reading comprehension. Application: This study quantitatively evaluated the cognitive loads of Koreans and foreigners through EEG, based on readers and the text difficulty, when they read Korean texts. The results of this study can be used for making Korean teaching materials or Korean education content and topic selection for foreigners. If research scope is expanded to reading process using an eye-tracker, the reading education program and evaluation method for foreigners can be developed on the basis of quantitative values.

A Study on Effect of Recirculated Exhaust Gas upon Performance and Exhaust Emissions in a Power Plant Boiler with FGR System (FGR 시스템 동력 플랜트 보일러의 성능 및 배기 배출물에 미치는 재순환 배기의 영향에 관한 연구)

  • Bae, Myung-whan;Jung, Kwong-ho;Park, Sung-bum
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.4
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    • pp.263-273
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    • 2016
  • The effect of recirculated exhaust gas on performance and exhaust emissions with FGR rate are investigated by using a natural circulation, pressurized draft and water tube boiler with FGR system operating at several boiler loads and over fire air damper openings. The purpose of this study is to apply the FGR system to a power plant boiler for reducing $NO_x$ emissions. To activate the combustion, the OFA with 0 to 20% is supplied into the flame. When the suction damper of two stage combustion system installed in the upper side of wind box is opened by handling the lever between $0^{\circ}$ and $90^{\circ}$, also, the combustion air supplied to burner is changed. It is found that the fuel consumption rate per evaporation rate did not show an obvious tendency to increase or decrease with rising the FGR rate, and $NO_x$ emissions at the same OFA damper opening are decreased, as FGR rates are elevated and boiler loads are dropped. While a trace amount of soot is emitted without regard to the operation conditions of boiler load, OFA damper opening and FGR rate, because soot emissions are eliminated by the electrostatic precipitator with a collecting efficiency of 86.7%.

Heat Transfer Analysis and Experiments of Reinforced Concrete Slabs Using Galerkin Finite Element Method (Galerkin 유한요소법을 이용한 철근콘크리트 슬래브의 열전달해석 및 실험)

  • Han, Byung-Chan;Kim, Yun-Yong;Kwon, Young-Jin;Cho, Chang-Geun
    • Journal of the Korea Concrete Institute
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    • v.24 no.5
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    • pp.567-575
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    • 2012
  • A research was conducted to develop a 2-D nonlinear Galerkin finite element analysis of reinforced concrete structures subjected to high temperature with experiments. Algorithms for calculating the closed-form element stiffness for a triangular element with a fully populated material conductance are developed. The validity of the numerical model used in the program is established by comparing the prediction from the computer program with results from full-scale fire resistance tests. Details of fire resistance experiments carried out on reinforced concrete slabs, together with results, are presented. The results obtained from experimental test indicated in that the proposed numerical model and the implemented codes are accurate and reliable. The changes in thermal parameters are discussed from the point of view of changes of structure and chemical composition due to the high temperature exposure. The proposed numerical model takes into account time-varying thermal loads, convection and radiation affected heat fluctuation, and temperature-dependent material properties. Although, this study considered standard fire scenario for reinforced concrete slabs, other time versus temperature relationship can be easily incorporated.

Characteristics of Saturation and Circulating Current Based on Winding and Iron Core Structure of Grid-connected Transformer in Energy Storage System (ESS 연계용 변압기의 결선방식 및 철심구조에 따른 순환전류와 포화특성에 관한 연구)

  • Tae, Dong-Hyun;Lee, Hu-Dong;Kim, Ji-Myung;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.4
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    • pp.39-48
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    • 2020
  • Since the fire accident of ESS (energy storage system) occurred at Gochang KEPCO Power Testing Center in August 2017, 29 fire cases with significant property losses have occurred in Korea. Although the cause of fire accidents have not been identified precisely, it should be considered battery and PCS (power conditioning system) as well as unbalance issues in the distribution system. In particular, circulating currents in a neutral line of a grid-connected transformer, which can affect a magnetized current, may have a negative effect on the ESS with unintentional core saturation and surge voltages at the secondary side of the transformer. Therefore, this paper proposes the modeling of the distribution system, which was composed of a substation, grid-connected transformer, and customer loads using PSCAD/EMTDC S/W, to analyze the phenomena of circulating current and surge voltages of the transformer with unbalanced currents in the distribution system. This paper presents a countermeasure for a circulating current with the installation of NGR (neutral grounding resistor) in grid-connected transformer. From the simulation results, it is clear that exceeding the circulating current and surge voltage at the secondary side of the transformer can be one of the causes of fire accidents.