• Title/Summary/Keyword: Cross-sectional factor

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Design of the Cross Sectional Shape of Intermediate Die for Shaped Drawing of Spline (스플라인 이형인발을 위한 중간 다이 단면형상 설계)

  • Lee, J.E.;Lee, T.K.;Lee, S.K.;Kim, B.M.
    • Transactions of Materials Processing
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    • v.17 no.8
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    • pp.627-632
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    • 2008
  • The cross sectional shape of intermediate die is one of important parameters to improve dimensional accuracy of final product in shaped drawing process. Until now, it has been designed by the experience or trial and error of the expert. In this study, the cross sectional shape of intermediate die for spline shape is determined by the electric fields analysis and scale factor method. The result of the electric fields analysis and scale factor method have been compared with that of the expert method. The effects of cross sectional shape on the dimensional accuracy were investigated by using FE-simulation. And then the multi-stage shaped drawing experiments were performed to verify the results of FE-simulation. As a result, the cross sectional shape from the electric fields analysis and scale factor method had the good dimensional accuracy. These two methods can be used for the method to obtain the cross sectional shape of intermediate die in shaped drawing process.

Study of Multi-Step Current Lead (다단 전류도입선 해석)

  • Moon, J.S.;Seol, S.Y.
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.379-384
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    • 2000
  • High-Tc superconducting current leads with multi-step and continually varied cross-sectional area are studied to reduce heat leak into cryostat and material use. Assuming conduction-cooled lead the cross-sectional area is reduced along the heat flow direction according to the increase of critical current density which increases with decreasing temperature. In this study, we also analyze the multi-step cross-sectional area High-Tc current leads. The multi-st데 current leads changes the cross-sectional area to have constant safety-factor at changed section. The heat leak into cryostat, total voume, safety-factor and the temperature profiles are compared to those of the constant safety-factor current leads. The developed methods are applied to the Bi-2223 superconductor sheathed with Ag-Au alloy.

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Cross-cultural Validation of Instruments Measuring Health Beliefs about Colorectal Cancer Screening among Korean Americans

  • Lee, Shin-Young;Lee, Eunice E.
    • Journal of Korean Academy of Nursing
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    • v.45 no.1
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    • pp.129-138
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    • 2015
  • Purpose: The purpose of this study was to report the instrument modification and validation processes to make existing health belief model scales culturally appropriate for Korean Americans (KAs) regarding colorectal cancer (CRC) screening utilization. Methods: Instrument translation, individual interviews using cognitive interviewing, and expert reviews were conducted during the instrument modification phase, and a pilot test and a cross-sectional survey were conducted during the instrument validation phase. Data analyses of the cross-sectional survey included internal consistency and construct validity using exploratory and confirmatory factor analysis. Results: The main issues identified during the instrument modification phase were (a) cultural and linguistic translation issues and (b) newly developed items reflecting Korean cultural barriers. Cross-sectional survey analyses during the instrument validation phase revealed that all scales demonstrate good internal consistency reliability (Cronbach's alpha=.72~.88). Exploratory factor analysis showed that susceptibility and severity loaded on the same factor, which may indicate a threat variable. Items with low factor loadings in the confirmatory factor analysis may relate to (a) lack of knowledge about fecal occult blood testing and (b) multiple dimensions of the subscales. Conclusion: Methodological, sequential processes of instrument modification and validation, including translation, individual interviews, expert reviews, pilot testing and a cross-sectional survey, were provided in this study. The findings indicate that existing instruments need to be examined for CRC screening research involving KAs.

Effect of Braid Structure on Yarn Cross-Sectional Shape

  • Lyons, Jason;Pastore, Christopher M.
    • Fibers and Polymers
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    • v.5 no.3
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    • pp.182-186
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    • 2004
  • The effect of braid construction parameters on yarn cross-sectional shape is presented in this paper. The location of the yam within the braid unit cell is quantified by a compaction factor. A range of braided fabrics were produced and optically measured for actual yarn cross-sectional shape. A comparison of the theoretical and experimental values shows good correlation. Design curves can be produced with the developed model to allow selection of appropriate braid process parameter to create yarns with desired cross-sectional geometries.

Analysis of HTS Current Lead with Variable Area (단면적 변화를 가지는 고온초전도체 전류도입선 해석)

  • 문성수;설승윤
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2000.02a
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    • pp.22-25
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    • 2000
  • To improve the performance of high temperature superconducting current leads, variable cross-sectional area is considered. The cross-sectional area is varied as a function of current density to fix the safety factor along lead length. New integration method is devised to find optimum cross-sectional area distribution. New design of current lead has low heat leak into cryostat and less material than constant cross-sectional area leads. Conduction cooled lead is considered. The developed method is applied to Bi2223 current leads sheathed Ag-Au alloy.

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Three Dimensional Last Data Generation System Design Utilizing SFFD and LFFD (LFFD 및 SFFD를 이용한 3차원 라스트 데이터 생성시스템 개발)

  • Kim, Si-Kyung;Park, In-Duck
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.2
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    • pp.113-118
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    • 2006
  • A new last design approach based on the Limb line FFD (LFFD) and Scale factor FFD (SFFD) is presented in this paper. The proposed last design method utilizes the dynamic trimmed parametric patches for the measured foot 3D data and last 3D data. Furthermore, the proposed last data generation system utilizes cross sectional data extracted obtained from the measured 3D foot data. First, the last design rule of the LFFD is constructed on the FFD lattice based on foot last shape analysis. Secondly, SFFD is constructed on the LFFD new lattice based on scale factor deformation. The scale factor is constructed on the boundary edges of polygonized patch and the cross section last data boundary edge of the polygon object. Suppose the two boundary curves have been preprocessed so that they run in the same direction and they forms the SF(Scale Factor). In addition, the control points of FFD lattice are derived with cross. sectional data interpolation methods from a finite set of 3D foot data.

Analysis of Factors Affecting Regional Total Fertility Rate: Using a Model Considering Cross-sectional Dependence (지역 합계출산율에 영향을 미치는 요인 분석: 횡단면 의존성을 고려한 모형을 이용하여)

  • So-Youn Kim;Su-Yeol Ryu
    • Asia-Pacific Journal of Business
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    • v.15 no.1
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    • pp.335-352
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    • 2024
  • Purpose - Low fertility rate is a serious problem, and this study analyzes factors affecting total fertility rate using panel data from 16 metropolitan cities and provinces in Korea from 2000 to 2022. Design/methodology/approach - Estimating the SAR model considering the weak cross-sectional dependence that exists in variables related to the regional total fertility rate, and using the DKSE estimation method considering the strong cross-sectional dependence. Findings - Estimation results considering weak and strong cross-sectional dependence were similar, confirming the robustness of the results. Female labor force participation rate has a positive effect on total fertility rate, and employment rate has no effect. However, the interaction term is a negative (-) sign. Crude marriage rate has a positive effect on total fertility rate, and apartment price has a slightly positive effect. Environmental factor has no effect, and policy factor has a negative effect. Research implications or Originality - In order for an increase in the female labor force participation rate to lead to an increase in the total fertility rate, qualitative improvements in female employment must be made. Financial investment policies for childbirth must increase their effectiveness. The problem of low fertility rate requires not only population policy but also social, economic, cultural, environmental, and policy conditions to be considered.

Effect of Divergence Ratio on Heat Transfer and Friction Factor in the Diverging Channel (확대 채널에서 확대율이 열전달과 마찰계수에 미치는 효과)

  • Oh, Se-Kyung;Lee, Myung-Sung;Jeong, Seong-Soo;Ahn, Soo-Whan
    • Journal of Power System Engineering
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    • v.17 no.1
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    • pp.64-70
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    • 2013
  • The heat transfer and friction factor characteristics of turbulent flows in three stationary channels have been investigated experimentally to check out the effect of divergence ratio. These are a constant cross-sectional channel and two diverging channels with ratio of divergence(Dho/Dhi) of 1.16 and 1.49. The measurement was conducted within the range of Reynolds numbers from 15,000 to 89,000 and the dimension of uniform cross-sectional test section is $100mm{\times}100mm$ at the cross section and 1,000 mm in length. The measurements of heat transfer coefficients and friction factors in the uniform channels were conducted as a reference. Because of the streamwise flow deceleration, the heat transfer and friction factor characteristics in the diverging channel were quite different from those of the constant cross-sectional channel. The effective friction factors and convective heat transfer coefficients increased with increasing the ratio of divergence of the channel.

Stability Analysis ofn HTS Current Lead with Constant Safety Factor (안전율이 일정한 초전도 전류도입선의 안정성해석)

  • Seol, Seoung-Yun
    • Progress in Superconductivity and Cryogenics
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    • v.2 no.2
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    • pp.15-19
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    • 2000
  • The stability of variable cross-sectional area HTS current lead is considered. The cross-sectional area is varied to have a constant safety factor which is defined as the ratio of operating current and critical current of superconductor. As the constant area HTS lead, the variable cross-sectional area HTS lead also has three steady states above the bifurcation point and only one steady state below the bifurcation point. The temperature profiles and current sharing ratios for each steady state are calculated. The heat dissipation into cryogenic system for super-conducting, intermediate, and upper states are compared. For Bi-2333 sheathed with silver-gold alloy 2m length of current lead, and the maximum temperature of upper state seems to be burn-out free below 5m length.

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Study of the Standard Testing Specifications for a Non-loading Performance Evaluation of Coating Material-sprayed Circular Steel Structures (뿜칠 피복 원형 철골구조의 비재하 내화성능 평가용 시험체 제안을 위한 연구)

  • Ok, Chi-Yeol;Kim, Jae-Jun
    • Fire Science and Engineering
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    • v.30 no.3
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    • pp.7-15
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    • 2016
  • The cross-sectional shape factor is used worldwide to evaluate the scientific performance of fire-resistant structures. In South Korea, however, a system for applying a cross-sectional shape factor has not been arranged and circular or rectangular steel pipes are commonly used for large-scale steel frame buildings. On the other hand, coating material-spray steel beams and pillars that have received the certification of a fire-resistant structure from recognized organizations are mostly limited to a H-beam. A H-beam is granted a wide range of certifications without size limitations from a non-loading performance test with test standards based on the relevant provisions. Other types of steel pipe are to be certified for fireresistance according to shape. In this study, a cross-sectional shape factor was used to propose standard testing specifications for the application of coating material-sprayed circular and rectangular steel pipes, eventually to set the scope of certification for reasonable fire-resistant structures.