• Title/Summary/Keyword: Materials property

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Study on the Thermal Property and Aging Prediction for Pressable Plastic Bonded Explosives through ARC(Heat-wait-search method) & Isothermal Conditions (ARC(Heat-wait-search method)와 Isothermal 조건을 이용한 압축형 복합화약의 열적 특성 및 노화 예측 연구)

  • Lee, Sojung;Kim, Seunghee;Kwon, Kuktae;Jeon, Yeongjin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.4
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    • pp.55-60
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    • 2018
  • The thermal property is one of the most important characteristics in the field of energetic materials. Because energy materials release decomposition heat, differential scanning calorimetry (DSC) is frequently used for thermal analysis. However, thermodynamic events, such as melting can interfere with DSC kinetic analysis. In this study, we use isothermal mode for DSC measurement to avoid thermodynamic issues. We also merge accelerating rate calorimetry(ARC) data with DSC data to obtain a robust prediction results for small scale samples and for large scale samples as well. For the thermal property prediction, advanced kinetics and technology solutions(AKTS) programs are used.

An Experimental Study on the Concrete Pore Structure Property (콘크리트의 공극 특성에 관한 실험적 연구)

  • Lee, Mun-Hwan;Jung, Mi-Kyung;Oh, Se-Chul;Seo, Chee-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.4
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    • pp.179-189
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    • 1999
  • This study attempts to propose an evaluation considering the property of concrete pore which affects the deterioration of neutralization and the rebar resistance of concrete. Understanding pore property of concrete in using extent, for practical using of concrete manufacturing condition. basic quality property and durability estimation etc, the results of the experiment are as follows. 1) The result of analysis pore property of every specimen with the method of area ratio, in limitation of $10^{-6}{\sim}10^{-5}m$, the pore distribution ratio was maximum. It was high value as W/C was increased and the unit cement content was decreased. 2) In case of using admixture. the volume of pores was some increased as variation of mixing content. In high W/C range, it was very increased compared with plain concrete. 3) Concerned with compressive strength and volume of pores in hardened concrete, it is possible compressive strength estimation using the property of concrete pores. 4) Direct measurement of concrete pore property is difficult. the valuation of the dynamic modulus of elasticity using ultrasonic wave velocity was available. 5) Quantitatively evaluation of concrete structure durability by past result of pore distribution estimation, and it can be estimative scale of property study on the concrete materials.

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A Study on the Distribution Methods of Tensile Property for Women′s Knit Block (여성용 Knit Block의 신장률 배분 방식에 관한 연구)

  • 허은영;조진숙
    • Journal of the Korean Home Economics Association
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    • v.42 no.8
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    • pp.203-218
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    • 2004
  • Recently, knitted materials are used more often than ever before in fashion. Therefore it is necessary to study their application into garment patterns. The purpose of this study was to develop a system by which the tensile property of knitted fabrics can be applied. In this study, 5 different distribution methods of tensile property were tested on 2 sample fabrics which have a lower and higher tensile property than moderate-stretch. The subjects were five women within an age range from 18 to 24 who showed average body figures. The major findings derived from this investigation were as follows; The 4th method was regarded as the most valid. The 4th method was fixed proportional alteration based on the reduction amount of bust girth, i.e. front (back) width and shoulder width reduced by 60% of the bust girth reduction and neck point reduced by 28% of the bust girth reduction. When the reduction was based on the proportion of the actual measurements, the alteration was too severe, so that the armhole curve was changed into a very uncomfortable curve.