• Title/Summary/Keyword: diffusion law

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Development and Application of a NCS-based Reference Operation Model for Contract Departments of the Korean Work-and-Study Parallel Colleges (한국형 일학습병행제 대학 계약학과의 NCS기반 표준운영모델 개발 및 적용)

  • Kang, Kiho;Kim, Uijung;Om, Kiyong
    • Journal of Practical Engineering Education
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    • v.11 no.1
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    • pp.61-73
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    • 2019
  • Recently the Korean life-long occupational skill development system is undergoing rapid change and innovation on the basis of NCS (National Competency Standards). In order for the NCS-based occupational training system to be successfully established, it is required to be accepted and applied in the higher education. Universities, however, hesitate to adopt NCS-based contracted education programs of the work-and-study cooperative system due to low relevance of university education to industrial needs and absence of the reference operation model for the NCS-based contracted education programs considering Korean small companies' particular needs. This study aims to develop and apply a reference operation model for NCS-based contracted education programs of the university-linked work-and-study parallel system, focusing on the Department of Mechanical Design Engineering of College of Work and Study in Parallel, Koreatech. In addition, several operational guidelines are suggested within the framework of current law and regulations for successful diffusion of the NCS-based reference operation model. The results of this study are expected to contribute to nation-wide proliferation of NCS-based contracted education programs in the higher education and motivating companies and universities to participate in the work-and-study parallel initiatives.

Effect of Grain Size and Drying Temperature on Drying Characteristics of Soybean (Glycine max) Using Hot Air Drying (열풍건조 시의 건조 온도와 입경에 따른 콩(Glycine max)의 건조 특성)

  • Park, Hyeon Woo;Han, Won Young;Yoon, Won Byong
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.44 no.11
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    • pp.1700-1707
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    • 2015
  • The effects of drying temperature on drying characteristics of soybeans with different grain sizes [6.0 (S), 7.5 (M), and 9.0 mm (L) (${\pm}0.2$)] with 25.0% (${\pm}0.8$) initial moisture content were studied. Drying temperatures varied at 25, 35, and $45^{\circ}C$, with a constant air velocity (13.2 m/s). Thin-layer drying models were applied to describe the drying process of soybeans. The Midilli-Kucuk model showed the best fit ($R^2$ >0.99). Based on the model parameters, drying time to achieve the target moisture content (10%) was successfully estimated. Drying time was strongly dependent on the size of soybeans and the drying temperature. The effective moisture diffusivity ($D_{eff}$) was estimated by the diffusion model based on Fick's second law. $D_{eff}$ values increased as grain size and drying temperature increased due to the combined effect of high temperatures and high drying rates, which promote compact tissue. Deff values of S, M, and L estimated were in the range of $0.83{\times}10^{-10}$ to $1.51{\times}10^{-10}m^2/s$, $1.17{\times}10^{-10}$ to $2.17{\times}10^{-10}m^2/s$, and $1.53{\times}10^{-10}$ to $2.95{\times}10^{-10}m^2/s$, respectively, whereas activation energy ($E_a$) based on drying temperature showed no significant differences in the size of soybeans.