• Title/Summary/Keyword: safety properties

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A Study on Electric Properties of Epoxy Resin on Filler Shape (충전제 형상이 미치는 에폭시 수지의 전기적 특성에 관한 연구)

  • 이성일
    • Journal of the Korea Safety Management & Science
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    • v.3 no.3
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    • pp.231-241
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    • 2001
  • The epoxy resin materials used in outdoor high voltage equipments are required to have the high electric performance because of the miniaturization. The frequence dependence of the permittivity and the loss tangent have important information. In this paper we describe the frequency dependence of the permittivity and the loss tangent for epoxy resin filled with silica and the influence of filler shapes on the dielectric properties. The increment of tan $\delta$ in the low frequency region is caused by the increment of both the electrical conductivity and the polarization due to the shape of filler and the water absorbed in and near the interface between fillers and resins. The result of charge current and discharge measure, electric conduction is increased according to voltage.

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The Cross-Sectional Dispersion of Housing and Business Cycle (경기변동과 주택형태별 수익률에 관한 소고(小考))

  • Kim, Jong-Kwon
    • Proceedings of the Safety Management and Science Conference
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    • 2009.04a
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    • pp.305-308
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    • 2009
  • According to the returns of Housing and business cycle over the period 1992 to 2007, it is a measure of the total volatility faced by investors in Housing properties. First, it isn't a distinct difference from business cycle contrary to U.S. Second, the rise of purchase price in total apartments moves up the consumer price index. According to the cross-sectional dispersion of returns and growth in net operating income (NOI) of apartments, industrial, retail and office properties using panel data for U.S. metropolitan areas over the period 1986 to 2002, it is a measure of the total volatility faced by investors in commercial real estate. To the extent that most of that volatility is difficult to diversify, cross-sectional dispersion may be an appropriate measure of risk.

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A Study on Degradation Behavior of 1Cr-1Mo-0.25V Steel (1Cr-1Mo-0.25V 강의 열화거동에 관한 연구)

  • 석창성;구재민;김동중;안하늘;박은수
    • Journal of the Korean Society of Safety
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    • v.15 no.4
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    • pp.8-14
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    • 2000
  • The remaining life estimation for the aged components in power plants as well as chemical plants are very important because mechanical properties of the components are degraded with time of service exposure in the high temperature. Since it is difficult to take specimens from the operating components to evaluate mechanical properties of components, accelerated aging technique are needed to estimate and analyse the material degradation. In the this study, test materials with 4 different degradation levels were prepared by isothermal aging heat treatment at $630^{\circ}C$. And tensile test, $k_{IC}$ test, hardness test and Scanning Electron Microscope analysis were performed in order to evaluate the degradation of 1Cr-1Mo-0.25V steels.

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Electrical Properties of Silicone Rubber for High-Voltage (고전압용 실리콘 고무의 전기적 특성)

  • 김왕곤;홍진웅
    • Journal of the Korean Society of Safety
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    • v.15 no.4
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    • pp.41-46
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    • 2000
  • Silicone rubbers are elastomeric materials and organic copolymers, of which backbone is siloxane with high bonding strength. Silicone rubbers have been used as an power insulator because they are well weather proof, ozone proof and have excellent electric characteristics, thermal stability, cold resistance and low surface energy. Especially, it is known that they have very excellent characteristics at 200[$^{\circ}C$]. For this study, we made silicone rubbers as specimens and measured volume resistivity due to applied voltage and a variation of temperature 25[$^{\circ}C$] to 180[$^{\circ}C$]. Also we measured dielectric loss tangent due to applied voltage at temperature range 25[$^{\circ}C$] to 180[$^{\circ}C$] and frequency range 20[Hz] to 1${\times}10^6$[Hz].

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Application of Light Collecting Probe with High Spatial Resolution to Spark-Ignited Spherical Spray Flames (불꽃점화 구형분무화염에서 고공간 분해능을 가진 집광프로브의 응용)

  • Yang Young-Joon
    • Journal of the Korean Society of Safety
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    • v.19 no.3 s.67
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    • pp.20-25
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    • 2004
  • In order to obtain the flame Propagation speed in freely falling droplet suspension Produced by an ultrasonic atomizer, a light collecting probe named Multi-color Integrated Cassegrain Receiving Optics (MICRO) is applied to spark-ignited spherical spray flames. Two MICRO probes are used to monitor time-series signals of OH chemilumine-scence from two different locations in the flame. The flame propagation speed is calculated by detecting the arrival time difference of the propagating flame front. In addition, time-series images of OH chemiluminescence are simultaneously obtained by a high-speed digital CCD camera to ensure the validity of the MICRO system. Furthermore, relationship between the spray properties measured by phase Doppler anemometer (PDA) and the flame propagation speed are discussed with k different experimental conditions by changing the fuel injection rate. It was confirmed that the MICRO probe system was very useful and convenient to obtain the flame propagation speed and that the flame propagation speed was different depending on the spray properties.

Effect of Ozone Treatment on the Changes of Fatty Acids, Organic acids, and Sensory Properties in Ginseng Powder (오존처리가 인삼분말의 지방산과 유기산 함량 및 향미특성에 미치는 영향)

  • 곽이성;최강주;김나미
    • Journal of Food Hygiene and Safety
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    • v.11 no.1
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    • pp.51-55
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    • 1996
  • As a preliminary experiment to investigate the effect of ozone sterelization on the ginseng powder, the changes of fatty acid composition and organic acid content and sensory properties in ginseng powder treated with ozone was investigated. Ginseng powder was treated with 0.5 ppm ozone for 24 hours and 48 hours, respectively. With increase in ozone treatment time, the content of crude lipid and increase. Contents of unsaturated fatty acid-linolenic acid, linoleic acid, and oleic acid, etc.-decreased with ozone treatment time, whereas saturated fatty acid or same number-stearic acid-increased odor, bitter taste, roasted taste and sweet taste were thiner with ozone treatment times, but pungent taste was thicker with those treatment. These changes of ordors and tastes of ginseng powder with ozone treatment were predicted by oxydation of lipids, flavor components and saponins.

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A Modeling Approach to Integrate Business Processes and Data Requirements (업무 프로세스와 데이터 요구사항의 통합 모델링)

  • Jang, Mu-Gyeong
    • Proceedings of the Safety Management and Science Conference
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    • 2011.04a
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    • pp.329-338
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    • 2011
  • Business processes are often of long duration, and include internal worker's decision making, which makes business processes to be exposed to many exceptional situations. These properties of business processes makes it difficult to design processes to support uncertainties from internal or external environments. The behavioral properties of business processes mainly depends on the data aspects of business processes. To formalize the data aspect of process modeling, this paper proposes a graph-based model, called Data Dependency Graph (DDG), constructed from dependency relationships specified between business data. The paper also defines a mechanism of describing a set of mapping rules that generates a process model semantically equivalent to a DDG, which is accomplished by allocating data dependencies to component activities.

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The Study on the Mechanical Properties of PP-Wood Materials according to Modifier Using Taguchi Method (다구찌 방법을 이용한 PP-Wood 소재에서 개질제의 첨가에 의한 기계적 특성 평가 연구)

  • Min, Young-Cho;Kang, Yun-Jin;Kang, Kyong-Sik
    • Proceedings of the Safety Management and Science Conference
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    • 2010.04a
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    • pp.293-301
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    • 2010
  • Wood-PP composite materials were prepared by Taguchi robust design method with L9 orthogonal array to optimize experimental conditions. Tensile strength of the composite materials was considered as the main properties. Amount of wood powder and modifier of resin were chosen as significant parameters. As the result of Taguchi analysis in this study, the amount of wood powder was the most influencing parameter on the increase of tensile strength. The optimal conditions were determined and these results were good agreement with data analyzed by Taguchi robust design method.

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Review and Application Strategies for Finance and Investment Metrics Using Breakdown Properties of Return On Equity(ROE) (ROE 분해구조의 특성을 이용한 재무투자지표의 고찰 및 적용방안)

  • Choi, Sungwoon
    • Proceedings of the Safety Management and Science Conference
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    • 2013.04a
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    • pp.687-692
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    • 2013
  • In this paper, we provide application strategies of representative finance and investment metrics using breakdown properties of Return On Equity(ROE). The research discusses the relationship of ROE for finance and investment metrics such as Return On Asset(ROA), Return On Invested Capital(ROIC), Price Book Ratio(PBR), and Price Earning Ratio(PER). Furthermore, we provide three different perspectives of its purpose and utility of Residual Income(RI) Models, Market Value(MV) Models and Enterprise Value(EV) Models.

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A Study on the Chemical Compositions of Powdered Sludge of Basalt on Jeju Island (건축용 내화 단열재 개발을 위한 제주도 현무암 석분 슬러지 화학조성에 대한 연구)

  • Kim, Min-Gyun;Kam, Sang-Kyu;Jeon, Yong-Han;Kim, Nam-Jin
    • Journal of the Korea Safety Management & Science
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    • v.21 no.4
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    • pp.45-49
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    • 2019
  • The basalt fiber is expected to become a trend for industrial fibers as they have better properties of heat-resistant, non-combustion, absorbent, soundproof, moistureproof, lightweight, corrosion resistant, and high strength properties. Also, the fiber is found to be non-toxic and harmless to the human body. Therefore, in this study, we analyzed the chemical and mineral compositions of powdered sludge of basalt produced at seven sites on Jeju Island for the development of fire resistance insulating material for a building. The results showed that the basalt stone sludge is made from only sodium calcium aluminum silicate and ferridioside components unlike the basalt rock.