• 제목/요약/키워드: Core Elements

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Development of super convergent Euler finite elements for the analysis of sandwich beams with soft core

  • Sudhakar, V;Gopalkrishnan, S;Vijayaraju, K
    • Structural Engineering and Mechanics
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    • v.65 no.6
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    • pp.657-678
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    • 2018
  • Sandwich structures are well known for their use in aircraft, naval and automobile industries due to their high strength resistance with light weight and high energy absorption capability. Sandwich beams with soft core are very common and simple structures that are employed in day to day general use appliances. Modeling and analysis of sandwich structures is not straight forward due to the interactions between core and face sheets. In this paper, formulation of Super Convergent finite elements for analysis of the sandwich beams with soft core based on Euler Bernoulli beam theory are presented. Two elements, Eul4d with 4 degrees of freedom assuming rigid core in transverse direction and Eul10d with 10 degrees of freedom assuming the flexible core were developed are presented. The formulation considers the top, bottom face sheets and core as separate entities and are coupled by beam kinematics. The performance of these elements are validated by results available in the published literature. Number of studies are performed using the formulated elements in static, free vibration and wave propagation analysis involving various boundary and loading conditions. The paper highlights the advantages of the elements developed over the traditional elements for modeling of sandwich beams and, in particular wave propagation analysis.

A comparative study of core data elements of bibliographic record in digital library (디지털 도서관을 위한 서지레코드 핵심데이터요소 비교분석)

  • 김상미;남태우
    • Journal of the Korean Society for information Management
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    • v.15 no.2
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    • pp.137-162
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    • 1998
  • The purpose of this paper is to present core elements of bibliographic records to effective cataloging a variety of information materials such as monographs, non-book materials, serials, and internet resources. At first, AACR2R bibliographic data elements, the minimal level cataloging, and core records proposed by Progrma for Cooperative Cataloging(PCC) in Library of congress are discussed. After that elements of Core Records, dublin Core, KORMARC, and AACR2R are compared. Upon the results, this study suggests mandatory common core elements and optional core elements for cost-effective cataloging to all kinds of documents including internet resources.

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Numerical comparison between lattice and honeycomb core by using detailed FEM modelling

  • Giuseppe, Pavano
    • Advances in aircraft and spacecraft science
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    • v.9 no.5
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    • pp.377-400
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    • 2022
  • The aim of this work is a numerical comparison (FEM) between lattice pyramidal-core panel and honeycomb core panel for different core thicknesses. By evaluating the mid-span deflection, the shear rigidity and the shear modulus for both core types and different core thicknesses, it is possible to define which core type has got the best mechanical behaviour for each thickness and the evolution of that behaviour as far as the thickness increases. Since a specific base geometry has been used for the lattice pyramidal core, the comparison gives us the opportunity to investigate the unit cell strut angle giving the higher mechanical properties. The presented work considers a detailed FEM modelling of a standard 3-point bending test (ASTM C393/C393M Standard Practice). Detailed FEM modelling addresses to detailed discretization of cores by means of beam elements for lattice core and shell elements for honeycomb core. Facings, instead, have been modelled by using shell elements for both sandwich panels. On lattice core structure, elements of core and facings are directly connected, to better simulate the additive manufacturing process. Otherwise, an MPC-based constraint between facings and core has been used for honeycomb core structure. Both sandwich panels are entirely built of Aluminium alloy. Prior to compare the two models, the FEM sandwich panel model with lattice pyramidal core needs to be validated with 3-point bending test experimental results, in order to ensure a good reliability of the FEM approach and of the comparison. Furthermore, the analytical validation has been performed according to Allen's theory. The FEM analysis is linear static with an increasing midspan load ranging from 50N up to 500N.

Study on Core Debris Recriticality During Hypothetical Severe Accidents in Three Element Core Design of The Advanced Neutron Source Reactor

  • Shin, Sung-Tack
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.05b
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    • pp.467-472
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    • 1996
  • This study discusses special aspects of severe accident related recriticality modeling and analysis in the Advanced Neutron Source (ANS) reactor.$^{1, 2)}$ The analytical comparison of three elements core to former two elements case is conducted including evaluation of suitable nuclear cross-section sets to account for the effects of system configulation, fuel and moderator mixture temperature, material dispersion and the other thermal-hydraulics. Three elements core ANS reactor is the alternative core design which was proposed as a modified core design, with three fuel elements instead of two, that would allow operation with only 50% enriched uranium (former uranium fuel is the baseline design value of 93%) A comprehensive test matrix of calculations to evaluate the threat of a criticality event in the ANS is described. Strong dependencies still on geometry, material constituents, and thermal-hydraulic conditions are verified. Therefore, the concepts of mitigative design features are qualified.d.

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Localization of Metadata Elements in the Art Museum Community

  • Nam, Young-Joon;Lee, Seung-Min
    • Journal of the Korean Society for Library and Information Science
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    • v.46 no.2
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    • pp.175-197
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    • 2012
  • The art museums in South Korea are mostly small-scaled institutions with small amount of art works. Thus, internationally accepted metadata standards such as CDWA and VRA Core may not be efficient to manage their collections. Because of these distinct local characteristics, there is a need to create a set of metadata elements that can be used for the art museum community in the country. This research aims to propose a set of metadata elements customized to fit into the context of small-scaled art museums in South Korea. The construction of the element set was not from scratch but on the basis of existing standards such as CDWA, VRA Core, and Dublin Core. By identifying core elements that are indispensable in describing art works and collecting opinions of experts in art museums, the proposed set of metadata elements is expected to support the operation and management of art works and satisfy the localized needs of the art museum community.

Internal Structure of Information Packages in Digital Preservation

  • Lee, Seungmin
    • Journal of Information Science Theory and Practice
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    • v.2 no.4
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    • pp.6-19
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    • 2014
  • The description of preserved resources is one of the requirements in digital preservation. The description is generally created in the format of metadata records, and those records are combined to generate information packages to support the process of digital preservation. However, current strategies or models of digital preservation may not generate information packages in efficient ways. To overcome these problems, this research proposed an internal structure of information packages in digital preservation. In order to construct the internal structure, this research analyzed existing metadata standards and cataloging rules such as Dublin Core, MARC, and FRBR to extract the core elements of resource description. The extracted elements were categorized according to their semantics and functions, which resulted in three categories of core elements. These categories and core elements were manifested by using RDF syntax in order to be substantially applied to combine metadata records in digital preservation. Although the internal structure is not intended to create metadata records, it is expected to provide an alternative approach to enable combining existing metadata records in the context of digital preservation in a more flexible way.

Possibility of S, O, Si and K in the Earth's Core Composition and its Problems

  • Lee, Han-Yeang
    • Journal of the Korean earth science society
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    • v.25 no.1
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    • pp.48-51
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    • 2004
  • The light element candidates such as S, O, Si, and K are discussed for the reasonable compositions in the earth's core since the available data show density difference from pure iron core. These candidates are favored by the some evidences such as depletion in the crust and mantle, and lower eutectic temperature of Fe-FeS melt for sulfur. FeO phase for oxygen, lighter mass than sulfur and solubility in metallic phases for silicon, and partitioning in Fe-FeS melt for potassium. However, other problems such as short experimental data, initial compositions of these elements, and oxidation state during the formation of the earth should be solved simultaneously to confirm these light elements.

Delayed fast neutron as an indicator of burn-up for nuclear fuel elements

  • Akyurek, T.;Shoaib, S.B.;Usman, S.
    • Nuclear Engineering and Technology
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    • v.53 no.10
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    • pp.3127-3132
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    • 2021
  • Feasibility study of burn-up analysis and monitoring using delayed fast neutrons was investigated at Missouri University of Science and Technology Reactor (MSTR). Burnt and fresh fuel elements were used to collect delayed fast neutron data for different power levels. Total reactivity varied depending on the burn-up rate of fuel elements for each core configuration. The regulating rod worth was 2.07E-04 𝚫k/k/in and 1.95E-04 𝚫k/k/in for T121 and T122 core configurations at 11 inch, respectively. Delayed fast neutron spectrum of F1 (burnt) and F16 (fresh) fuel elements were analyzed further, and a strong correlation was observed between delayed fast neutron emission and burn-up. According to the analyzed peaks in burnt and fresh fuels, reactor power dependency was observed and it was determined that delayed neutron provided more reliable results at reactor powers of 50 kW and above.

A Study on Elements and Procedure of Instruction Consulting for Successful Flipped Learning (성공적인 Flipped Learning을 위한 수업컨설팅 요소 및 절차 연구)

  • Choi, Jeong-bin;Kang, Seung-Chan
    • Journal of Engineering Education Research
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    • v.19 no.2
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    • pp.76-82
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    • 2016
  • The purpose of this study is to identify core elements required of instruction consulting and to develop a systematic consulting procedure for successful Flipped Learning. The main contents of this study to achieve its purpose are as follows. First, core elements required of consulting are deduced by analyzing cases of instruction implemented with Flipped Learning. Second, consulting procedure is constructed based on core consulting elements of Flipped Learning. Based on the study results, the 3P process is suggested as the elements and procedure of instruction consulting for Flipped Learning. The 3P process has the following characteristics. The first stage Preparation involves guiding students to have an objective viewpoint about the lesson beginning with building a relationship with the instructor. Also, a lesson plan and source materials for lesson are selected and developed. The second stage Performance involves implementing lesson coaching oriented towards cooperative problem-solving to find better direction. The last stage Post-review involves introspection necessary for continuous quality improvement of lessons. The validity of the instruction consulting elements for Flipped Learning applied to deduce the aforementioned results has been verified after specialist review and field application.

Promoting Strategies by Development Stage of Region Based Agricultural Cluster Using a Multi-disciplinary Approach (다학문적 접근을 통한 지역농업 클러스터의 단계별 추진전략)

  • Choi, Sang-Ho;Choi, Hung-Kyu;Lee, Min-Soo;Choe, Young-Chan
    • Journal of Korean Society of Rural Planning
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    • v.11 no.4 s.29
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    • pp.33-45
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    • 2005
  • This study investigates the core elements of the formation and development of cluster using a multi-disciplinary approach and suggests a promoting strategy by development stage of cluster. As a sub-category of regional innovation system, the cluster has been considered as one of the most noticeable methodological argument to make the regional innovation system come true. In the meantime, this study examines the core elements of cluster shown in the theories and examples through six academic fields such as economics, geography, regional development, business administration, sociology and pedagogy and their educational back-ground. By means of establishing the incubation stage in the development of cluster, core elements are composed in the stages of birth, incubation and evolution in subsequent manner. A promoting strategy will be suggested through the implication of core elements in the reestablished stages.