• Title/Summary/Keyword: diffusions

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A Study on Field Applications of Polymer-Modified Warm Asphalt Concrete Mixture using Admixture (첨가제를 이용한 중온형 폴리머 개질 아스팔트 콘크리트 혼합물의 실용화 연구)

  • Kim, Nak-seok;Lee, Jin-goo;Park, Seok-soon
    • Journal of the Society of Disaster Information
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    • v.6 no.1
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    • pp.28-43
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    • 2010
  • This paper presents the field applications of polymer-modified warm asphalt mixture which can reduce the temperature during the production and field constructions. The amount of fuel consumptions and $CO_2$ diffusions can be reduced by much using the polymer-modified warm asphalt mixture instead of the conventional polymer-modified asphalt mixture. According to the research results, the polymer-modified warm asphalt mixture can be utilized without additional temperature increasement and performance sacrifice during the plant production and public service, respectively. As a result, it is considered that the application of the polymer-modified warm asphalt mixture has the potential of convenience in constructions management and reducing the environmental damages.

Grain Boundary Characteristics and Stress-induced Damage Morphologies in Sputtered and Electroplated Copper Films (스퍼터링 및 전기 도금으로 제조된 구리 박막에서의 표면 결함에 미치는 결정립계의 영향)

  • Park, Hyun;Hwang, Soo-Jung;Joo, Young-Chang
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2003.05a
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    • pp.4-4
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    • 2003
  • Various Cu films were fabricated using sputtering and electroplating with and without additive, and their surface damages after annealing were investigated. After annealing at 43SoC, the difference between damage morphologies of the films was observed. In some films stress-induced grooves along the grain boundaries were observed, while in the others voids at the grain boundary triple junctions were observed. It was also observed that the stress-induced groove was formed along the high energy grain boundaries. It was found out that the difference of the morphologies of surface damages in Cu films depends on not process type but grain boundary characteristics. To explain the morphological difference of surface damages, a simple parameter considering the contributions of grain structures and grain boundary characteristics to surface and grain boundary diffusions is suggested. The effective grain boundary area, which is a function of grain size, film thickness and the fraction of high energy grain boundaries, played a key role in the morphological difference.

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Self-Diffusion of THO within Tactic Poly(2-hydroxyethyl methacrylate) Membranes

  • Kim, Hye-Kyeong;Jhon, Mu-Shik
    • Bulletin of the Korean Chemical Society
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    • v.4 no.3
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    • pp.128-132
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    • 1983
  • The self-diffusion experiment of water was performed across two series of tactic poly(2-hydroxyethyl methacrylate), P(HEMA) membranes prepared by crosslinking with various amount of hexamethylene diisocyanate (HMDIC). The tagging material was tritium hydroxide (THO) and the efflux of THO was counted on a Liquid Scintillation Counter. The transport data of THO show that the permeability decreases as the amount of HMDIC increased from 2.5 to 10 mole % and the self-diffusions coefficient shows a parallel trend with it. The diffusivity data was discussed in terms of the change of water structural orderliness within membranes. Using the relation between viscosities and diffusivities derived from Eyring's absolute rate theory, the corresponding viscosities of water within two series of tactic P(HEMA) membranes were obtained. From this, it is seen that the viscosity of water within tactic P(HEMA) membranes may have the same values with those of supercooling water whose temperature ranges from -28 to -$36^{\circ}C.$.

The Study of Segmentation of Internet Fashion Information Users and Diffusion Outcomes: Application of a Use-Diffusion Model (사용확산에 따른 인터넷 패션정보 사용자 시장세분 및 확산성과 연구)

  • Song, Ki Eun;Hwang, Sun Jin;Kim, Yunsik
    • Journal of the Korean Society of Clothing and Textiles
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    • v.37 no.6
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    • pp.725-736
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    • 2013
  • This study segments information users according to depth and variety of use diffusion in order to differentiate between the influence of fashion information spread and diffusions from each segmented group. Data were collected from a fashion community to perform a social network analysis that used UCINET 6.0. Members completed the survey materials and the network materials were utilized in the analysis to test the hypothesis. The segmented groups of information users determined the study results according to use diffusion and the variables that affect them. The variables affecting information diffusion outcomes indicate different significant influence factors on each segmented market. Information variety and complexity represents elevated information reproductions and verbal acceptances from information diffusion outcomes.

Thermodynamic Properties and Self Diffusions from Rheological Parameters of Eyring-Halsey Model (Eyring-Halsey 모델의 유동파라메타로부터 열역학 성질과 자체 확산)

  • Kim, Nam Jeong
    • Journal of the Korean Chemical Society
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    • v.58 no.3
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    • pp.251-257
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    • 2014
  • The stress relaxation of poly(methyl acrylate)-poly(acrylonitrile) copolymer samples were carried out in air and distilled water at various temperatures using the tensile tester with the solvent chamber. The rheological parameters were obtained by applying the experimental stress relaxation curves to the theoretical equation of the Eyring-Halsey non-Newtonian model. The self diffusion, hole volume, viscosities, and thermodynamic parameters of copolymer samples were calculated from rheological parameters and crystallite size in order to study of flow segments in amorphous region. It was observed that the rheological parameters of these copolymer samples are directly related to the self diffusion, hole volume, viscosities, and thermodynamic parameters of flow segments.

An Experimental Study on the Break-up Characteristics of Twin-Fluid Nozze According to tile Variations of Feeding Mass-ratio (공급 질량비 변화에 따른 2유체 노즐의 액주분열특성에 관한 실험적 연구)

  • Kang, S.J.;Oh, J.H.;Rho, B.J.
    • Journal of ILASS-Korea
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    • v.1 no.1
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    • pp.63-75
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    • 1996
  • The purpose of this study is to investigate the break-up characteristics by taking advantage of a two-phase coaxial nozzle. Air and water are utilized as working fluids and the mass ratio air/water has been controlled to characterize the atomization, diffusion and development of mixing process. By way of a photographic technique, conventional developing structures and diffusion angles have been analyzed systematically with variations of mass ratios. The turbulent flow components of the atomized particles were measured by a two channel LDV system and the data were treated by an on-lined measurement equipment. According to the photographic results the spreading angles decreased because the axial inertia moment was relatively higher than the lateral one with respect to the increase of mass ratio. It is found the jet flow diffuses linearly in a certain limit region while the atomizing characteristics, in terms of the distributions of particle diameters did not show particular differences. It may be expected that these fundamental results can be used as reference data in studying the atomization, breakup and diffusions.

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Motivations and Characteristics of Hashtag Users

  • Kim, Gwon-Il;Jung, Ga Yeon;Song, Ye Ji;Park, Jee-Sun
    • Journal of Fashion Business
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    • v.19 no.6
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    • pp.112-126
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    • 2015
  • In social environments, hashtags have been widely adopted and have become a new form of language for users. The current study attempts to enhance our understanding of users and their motivations to use hashtags when posting fashion-related information. Specifically, this study examines whether user characteristics (fashion leadership, conspicuousness) influence their motivations to use hashtags (curation, self-presentation, information diffusion), which then leads to behavioral intentions to continue to use hashtags and recommend the same to others. An online survey was administered to test our research questions. A total of 136 consumers in their 20s, 30s, and 40s living in Korea were used for data analysis. Structural equation modeling was conducted, which revealed that fashion leadership and conspicuousness had a positive impact on users' motivations of curation, self-presentation, and information diffusion. Motivations of self-presentation and information diffusions were found to affect users' behavioral intentions while curation had no significant impact. Practical implications are presented.

EBCO - Efficient Boundary Detection and Tracking Continuous Objects in WSNs

  • Chauhdary, Sajjad Hussain;Lee, Jeongjoon;Shah, Sayed Chhattan;Park, Myong-Soon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.11
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    • pp.2901-2919
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    • 2012
  • Recent research in MEMS (Micro-Electro-Mechanical Systems) and wireless communication has enabled tracking of continuous objects, including fires, nuclear explosions and bio-chemical material diffusions. This paper proposes an energy-efficient scheme that detects and tracks different dynamic shapes of a continuous object (i.e., the inner and outer boundaries of a continuous object). EBCO (Efficient Boundary detection and tracking of Continuous Objects in WSNs) exploits the sensing capabilities of sensor nodes by automatically adjusting the sensing range to be either a boundary sensor node or not, instead of communicating to its neighboring sensor nodes because radio communication consumes more energy than adjusting the sensing range. The proposed scheme not only increases the tracking accuracy by choosing the bordering boundary sensor nodes on the phenomenon edge, but it also minimizes the power consumption by having little communication among sensor nodes. The simulation result shows that our proposed scheme minimizes the energy consumption and achieves more precise tracking results than existing approaches.

Effect of Milling Time on the Microstructure and Phase Transformation Behaviors of Ni-B Powder During Mechanical Alloying Process (Ni-B 분말의 기계적 합금화 과정에서 밀링시간에 따른 미세조직과 상변화 거동)

  • Kim, Jung-Geun;Lee, Wook-Jin;Park, Sung-Kyun;Park, Ik-Min;Park, Yong-Ho
    • Journal of Powder Materials
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    • v.18 no.6
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    • pp.496-501
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    • 2011
  • In this study, the effect of milling time on the microstructure and phase transformation behaviors of Ni-12 wt.%B powders was investigated using vibratory ball milling process. X-ray diffraction patterns showed that the phase transformation of mixed Ni-B elemental powder occurred after 50 hours of milling, with a formation of nickel boride phases. Through the study of microstructures in mechanical alloying process, it was considered that ball milling strongly accelerates solid-state diffusions of the Ni and B atoms during mechanical alloying process. The results of X-ray photoelectron spectroscopy showed that most of B atoms in the powder were linked to Ni with a formation of nickel boride phases after 200 hours of milling. It was finally concluded that mechanical alloying using ball milling process is feasible to synthesize fine and uniform nickel boride powders.

The Factors Affecting Breadth and Depth of Diffusion for Knowledge Management Systems (지식관리시스템의 수직적 확산과 수평적 확산에 관한 실증적 연구)

  • Suh, Chang-Kyo;Seol, Jin-Young
    • Knowledge Management Research
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    • v.9 no.3
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    • pp.77-105
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    • 2008
  • This study primarily aims at identifying what factors significantly affect the diffusion of knowledge management systems(KMS) and finding out how these identified factors can be effectively managed, especially for Korean companies. The research model is derived based on previous researches on innovation diffusion, information systems implementation, and KMS. The model is used to examine the role of determinants in influencing the extent to which KMS is diffused within organizations. Independent variables of this research are composed of technical characteristics, organizational characteristics and environmental characteristics. 'Breadth of diffusion' and 'depth of diffusion' concept are used to measure the extent of KMS diffusion which is the dependent variable of this model. The 101 companies of total 1,000 samples responded to the survey. To analyze tile results of this empirical study, we performed the multiple regression analysis. As a result, it was shown that the relative advantage, complexity, information system maturity, size, top management support, champion, competitive pressure have influences on both the breadth and the depth diffusions. On the other hand, the organizational culture, valuation and compensation, and uncertainty of environmental factors were not verified to be significant. This empirical study will provide Korean companies with insights into effective ways to diffuse the KMS and succeed in business competition.

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