• Title/Summary/Keyword: material heterogeneity

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Characteristics of Warm Acupuncture Reported in Experimental Studies: A Descriptive Narrative Review

  • Choi, Ji Won;Choi, Seo Young;Lee, Ji Sun;Yang, Gi Young
    • Journal of Acupuncture Research
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    • v.36 no.3
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    • pp.131-139
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    • 2019
  • Background: This study aimed to investigate the correlation between heat transmission and intervention factors for warm acupuncture (such as features of acupuncture material and moxa, the treatment method, and clinical symptoms). Methods: Korean, English, Chinese and Japanese databases were analysed. Experimental studies that explored the association between thermal stimulation delivery and warm acupuncture intervention factors were included. The peak temperature, time to reach the peak temperature, and time of the effective stimulus, were set as the major parameters and analysed. Results: A total of 12 studies were included. Two studies were associated with the acupuncture needle material, 4 studies associated with the moxa mass, 1 study associated with the moxa density, 2 studies associated with the location of ignition, and 1 study associated with treatment environment were reviewed. The reporting quality of the 12 studies was low. Conclusion: This study provided limited information because of the heterogeneity of materials and parameters depending on each experiment. Further studies should clarify the correlation between heat transmission and intervention factors for warm acupuncture.

On the Interdisplinary Linkage Framework between Engineering Discipline and Social Science Discipline (과학기술-사회과학 연계모형의 모색)

  • 박용태
    • Proceedings of the Technology Innovation Conference
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    • 1997.12a
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    • pp.70-88
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    • 1997
  • Recently, the interdisciplinary linkage between engineering and social science has received an increasing attention as an emerging education discipline. Due to intrinsic complexity of innovation process and heterogeneity of disciplinary nature, however there exists little, if not no, effort to draw a common framework in terms of educational scope and contents of the new subject. This paper presents a number of criteria and guidelines for building up new educational framework by integrating engineering subject and social science subject. Specifically, three neo-disciplines, technology policy, technology management, and economics of technology are considered since it is postulated that the forementioned disciplines have established academic identity and fundamental structure By nature, this paper is an exploratory and seminal one. It is not the purpose of this paper to provide a concrete table of contents of educational material. Instead, it merely brings up a discussion topic for the wide audience of academic arena, leaving the gradual consensus and convergence as future task.

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Three-dimensional numerical simulation and cracking analysis of fiber-reinforced cement-based composites

  • Huang, Jun;Huang, Peiyan
    • Computers and Concrete
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    • v.8 no.3
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    • pp.327-341
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    • 2011
  • Three-dimensional graphic objects created by MATLAB are exported to the AUTOCAD program through the MATLAB handle functions. The imported SAT format files are used to produce the finite element mesh for MSC.PATRAN. Based on the Monte-Carlo random sample principle, the material heterogeneity of cement composites with randomly distributed fibers is described by the WEIBULL distribution function. In this paper, a concept called "soft region" including micro-defects, micro-voids, etc. is put forward for the simulation of crack propagation in fiber-reinforced cement composites. The performance of the numerical model is demonstrated by several examples involving crack initiation and growth in the composites under three-dimensional stress conditions: tensile loading; compressive loading and crack growth along a bimaterial interface.

Analytical study on Reinforced Concrete Deep Beams with Opening (철근콘크리트 유공 깊은 보에 대한 해석적 연구)

  • 이석주;이종권;이병해
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.587-592
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    • 2000
  • As the residential spaces become high-rised and high-density, Multi-story buildings were constructed with transfer girders, Deep beams, wall foundations, floor diaphragms an shear walls which may have column offsets. Especially, In the analysis and design of Multi-story buildings, the lateral loads must be taken into account. But, there have been no appropriate theory and national design code for predicting ultimate shear strength of reinforced concrete Deep beams with web opening. Only empirical and semi-empirical formulas for predicting their ultimate load bearing capacities due to the complexities of the structural non-linearity and material heterogeneity. So this study analyze tow-dimensional finite element model that represents exactly the behavior of real structures with SBETA which are general nonlinear finite element analysis program, and compare the results with that from the real reinforced Concrete Deep beams with web opening tests. From the comparison, and parametric study, The Study presents the elementary data of the earthquake resistance for the reinforced concrete Deep beams with web opening.

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Assessing the Impact of Locally Produced Aerosol on the Rainwater Composition at the Gosan Background Site in East Asia

  • Han, Yeongcheol;Huh, Youngsook
    • Asian Journal of Atmospheric Environment
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    • v.8 no.2
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    • pp.69-80
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    • 2014
  • It is often assumed that atmospheric observations at remote sites represent long-range transport of airborne material, and local influences are overlooked. We evaluated the impact of local input on the rainwater composition at Gosan Station, a strategic site for monitoring the continental outflow from Asia. We analyzed a 14-year record of rainwater chemical composition archived by the Korea Meteorological Administration and detected local terrestrial contribution for nitrate, sulfate and ammonium. We also measured the chemical composition of rainwater sampled simultaneously at multiple locations within the premises of the Gosan Station, from which local influence with meter-scale spatial heterogeneity could be discerned. We estimate that the local input accounted for at least ~10% of the wet deposition of nitrogen and ~12% of the wet deposition of sulfur during the 14 years. This highlights the significance of the local influence, which should be carefully assessed when interpreting atmospheric observations at this site.

Hierarchical multiscale modeling for predicting the physicochemical characteristics of construction materials: A review

  • Jin-Ho Bae;Taegeon Kil;Giljae Cho;Jeong Gook Jang;Beomjoo Yang
    • Computers and Concrete
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    • v.33 no.3
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    • pp.325-340
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    • 2024
  • The growing demands for sustainable and high-performance construction materials necessitate a deep understanding of their physicochemical properties by that of these heterogeneities. This paper presents a comprehensive review of the state-of-the-art hierarchical multiscale modeling approach aimed at predicting the intricate physicochemical characteristics of construction materials. Emphasizing the heterogeneity inherent in these materials, the review briefly introduces single-scale analyses, including the ab initio method, molecular dynamics, and micromechanics, through a scale-bridging technique. Herein, the limitations of these models are also overviewed by that of effectively scale-bridging methods of length or time scales. The hierarchical multiscale model demonstrates these physicochemical properties considering chemical reactions, material defects from nano to macro scale, microscopic properties, and their influence on macroscopic events. Thereby, hierarchical multiscale modeling can facilitate the efficient design and development of next-generation construction.

A Study on Space of Conversion Communication Method through Materials in Commercial Space - Focusing on Domestic and International Commercial Spaces in 2008~2012 - (상업공간에서 재료를 통한 공간의 컨버전 소통 방법 연구 - 2008~2012년 국내·외 상업공간을 중심으로 -)

  • Ji, Ju-Yeon;Seo, Ji-Eun
    • Korean Institute of Interior Design Journal
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    • v.22 no.2
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    • pp.194-202
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    • 2013
  • Commercial spaces are very sensitive in terms of trend and uniqueness, and many elements expressing space coexist together with brilliant ideas aiming to attract consumer attention and even induce sudden desire of purchase. Coexistence in space is expressed in various ways and out of those ways, representation by material is especially apparent. The application of material does not individually influence the expression of space, but the characteristics of multiple materials applied contribute to the distinction of space through mutual communication. This study intends to analyze how conversion is centered to express the distinction of space through materials communicated in space. The detailed study results are as follows. First, the conversion expression method of material resulted as 'Substitution', 'Contrast', 'Assimilation', 'Creation'. These four was divided and analyzed into 'Time', 'Space', 'Genre'. As a result of this analysis, such significances were shown as 'Contrast' in 'Time', 'Substitution' in 'Space', and 'Assimilation' in 'Genre'. Second, the conflict due to heterogeneity by conversion of 'Contrast' in 'Time' through past and current materials appeared to induce interest amongst consumers. Third, within 'Space', 'Substitution' of natural/artificial materials was noticeably applied. This is evaluated as a constructive way of expressing natural forms into artificial forms further intending to provoke attention and stimulate emotion. Fourth, in conversion through 'Assimilation' in 'Genre', rather than using materials only from other areas, synchronizing it by combining architectural materials is an effective method. Such results are thought to be a distinctive design method that draws attention of customers by communicating disparate materials in commercial space. Thus, the study results are expected to be utilized as an elementary resource in designing commercial space with character and high satisfaction.

Separation of Non-covalently Functionalized Graphene Nanoplatelets via Salting-out Process (염석법을 이용한 비공유 기능기화된 그래핀 나노플레이트렛의 분리 공정 연구)

  • Kim, Joonhui;Yoo, Sung Chan;Cha, Jaemin;Ryu, Hojin;Hong, Soon Hyung
    • Composites Research
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    • v.32 no.3
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    • pp.134-140
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    • 2019
  • Graphene nanoplatelets (GNP), one of the graphene derivatives is famous as the most proper candidate for industrial applications. However, current performance of GNPs as reinforcing filler in composites is limited by their agglomeration and physicochemical heterogeneity. Herein, an approach to produce non-covalently functionalized GNPs (F-GNPs) is reported which possesses potential to be extended as the industrial level of mass production. The one-step functionalization process uses melamine, a low-cost chemical, to prevent agglomeration and dispersion in polar solvents. Furthermore, a purification strategy called salting-out process based on differences in the dispersibility of the individual F-GNP flakes is reported to separate F-GNPs. The functionalization and separation process developed in this paper provides a strategy to use GNPs at the industrial level in composite applications.

Three-Dimensional Numerical Simulation of Impacts of Layered Heterogeneity and Groundwater Pumping Schemes on Seawater Intrusion (해수 침투에 대한 층상 불균질성 및 지하수 양수 방식의 영향 삼차원 수치 모의)

  • Park, Hwa-Seok;Kihm, Jung-Hwi;Yum, Byoung-Woo;Kim, Jun-Mo
    • Journal of Soil and Groundwater Environment
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    • v.13 no.4
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    • pp.8-21
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    • 2008
  • A series of three-dimensional numerical simulations using a hydrodynamic dispersion numerical model is performed to analyze quantitatively impacts of layered heterogeneity of geologic media and groundwater pumping schemes on groundwater flow and salt transport in coastal aquifer systems. A two-layer heterogeneous coastal aquifer system composed of a lower sand layer (aquifer) and an upper clay layer (aquitard) and a corresponding single-layer homogeneous coastal aquifer system composed of an equivalent lumped material are simulated to evaluate impacts of layered heterogeneity on seawater intrusion. In addition, a continuous groundwater pumping scheme and two different periodical groundwater pumping schemes, which withdraw the same amount of groundwater during the total simulation time, are applied to the above two coastal aquifer systems to evaluate impacts of groundwater pumping schemes on seawater intrusion. The results of the numerical simulations show that the periodical groundwater pumping schemes have more significant adverse influences on groundwater flow and salt transport not only in the lower sand layer but also in the upper clay layer, and groundwater salinization becomes more intensified spatially and temporally as the pumping intensity is higher under the periodical groundwater pumping schemes. These imply that the continuous groundwater pumping scheme may be more suitable to minimize groundwater salinization due to seawater intrusion. The results of the numerical simulations also show that groundwater salinization in the upper clay layer occurs significantly different from that in the lower sand layer under the periodical groundwater pumping schemes. Such differences in groundwater salinization between the two adjacent layers may result from layered heterogeneity of the layered coastal aquifer system.

Deep proximal margin rebuilding with direct esthetic restorations: a systematic review of marginal adaptation and bond strength

  • Hoda S. Ismail;Ashraf I. Ali;Rabab El. Mehesen;Jelena Juloski;Franklin Garcia-Godoy;Salah H. Mahmoud
    • Restorative Dentistry and Endodontics
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    • v.47 no.2
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    • pp.15.1-15.18
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    • 2022
  • This review aimed to characterize the effect of direct restorative material types and adhesive protocols on marginal adaptation and the bond strength of the interface between the material and the proximal dentin/cementum. An electronic search of 3 databases (the National Library of Medicine [MEDLINE/PubMed], Scopus, and ScienceDirect) was conducted. Studies were included if they evaluated marginal adaptation or bond strength tests for proximal restorations under the cementoenamel junction. Only 16 studies met the inclusion criteria and were included in this review. These studies presented a high degree of heterogeneity in terms of the materials used and the methodologies and evaluation criteria of each test; therefore, only a descriptive analysis could be conducted. The included studies were individually evaluated for the risk of bias following predetermined criteria. To summarize the results of the included studies, the type of restorative material affected the test results, whereas the use of different adhesive protocols had an insignificant effect on the results. It could be concluded that various categories of resin-based composites could be a suitable choice for clinicians to elevate proximal dentin/cementum margins, rather than the open sandwich technique with resin-modified glass ionomers. Despite challenges in bonding to proximal dentin/cementum margins, different adhesive protocols provided comparable outcomes.