• Title/Summary/Keyword: Engineering M&S

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Star Building Materials Study on Wood Structure and Combustion Characteristics (건축재료별 목재구조와 연소특성에 관한연구)

  • Kim, Jong-Buk;Park, Young-Ju;Lee, Si-Young
    • Fire Science and Engineering
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    • v.30 no.5
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    • pp.60-66
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    • 2016
  • This study investigated the structure and combustion characteristics of four species, Timber Douglas-fir being used construction materials (finishes), Lauan, Cryptomeria japonica, Pinus densiflora trees in the area. In lookong into the ignition characteristics was a time range of ignition (TTI) appeared in the 21 s~32 s, especially Pinus densiflora TTI is ignited in a relatively rapid 601 s to 21 s than the other materials were destroyed in the 631 s. The maximum heat release rate and average heat release rate is Pinus densiflora > Lauan > Cryptomeria japonica > Douglas-fir showed a net. Barrel emissions are Lauan > Douglas-fir > Pinus densiflora > Cryptomeria japonica was in order. The total emissions was postponed Pinus densiflora $424.80m^2/m^2$, Lauan $185.93m^2/m^2$. Douglas-fir carbon emissions of 1460, showing 0.185 kg/kg CO maximum value from s $CO_2$ values show the maximum value to 15,986 kg/kg in 750 s stopped in the 3,090 s. Next, the study suggested methods to utilize as the basic data for evaluating the safety of the fire as a building material.

Synthesis and Thermoelectric Properties of Skutterudite CoSb3 (Skutterudite CoSb3의 합성 및 열전특성)

  • Kim I. H.;You S. W.;Park J. B.;Lee J. I.;Ur S. C.;Jang K. W.;Choi G. S.;Kim J. S.;Kim H. J.
    • Korean Journal of Materials Research
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    • v.15 no.10
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    • pp.667-670
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    • 2005
  • Binary skutterudite $CoSb_3$ compounds were prepared by the arc melting and hot pressing processes and their thermoelectric properties were investigated in the range from 300 to 600 K. Annealing effect was correlated to phase transformation and homogenization. Thermoelectric properties of the arc-melted and hot-pressed $CoSb_3$ were discussed and compared. Undoped intrinsic $CoSb_3$ prepared by the arc melting showed p-type conduction, while it showed metallic behavior with increasing measuring temperature. However, hot pressed specimens showed n-type conduction, possibly due to Sb evaporation. Thermoelectric properties were remarkably improved by annealing In vacuum and they were closely related to phase transformation.

Characteristics of conductive rubber belt on the abdomen to monitor respiration (호흡 감지를 위한 복부 부착형 전도성 고무소자의 계측특성)

  • Kim, Kyung-Ah;Kim, Sung-Sik;Cho, Dong-Wook;Lee, Seung-Jik;Lee, Tae-Soo;Cha, Eun-Jong
    • Journal of Sensor Science and Technology
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    • v.16 no.1
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    • pp.24-32
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    • 2007
  • Conductive rubber material was molded in a belt shape to measure respiration. Its resistivity was approximately $0.03{\;}{\Omega}m$ and the resistance-displacement relationship showed a negative exponent. The temperature coefficient was approximately $0.006{\;}k{\Omega}/^{\circ}C$ negligible when practically applied on the abdomen. The conductive rubber belt was applied on a normal male's abdomen with the dimensional change measured during resting breathing. The abdominal signal was differentiated ($F_{m}$) and compared with the accurate standard air flow rate signal ($F_{s}$) obtained by pneumotachometry. $F_{m}$ and $F_{s}$ differed in waveform, but the start and end timings of each breaths were clearly synchronized, demonstrating that the respiratory frequency could be accurately estimated before further processing of $F_{m}$. $F_{m}-F_{s}$ loop showed a nonlinear hysteresis within each breath period, thus 6 piecewise linear approximation was performed, leading to a mean relative error of 14 %. This error level was relatively large for clinical application, though customized calibration seemed feasible for monitoring general variation of ventilation. The present technique would be of convenient and practical application as a new wearable respiratory transducer.