• 제목/요약/키워드: Mixed study

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현장 적용성을 고려한 섬유혼입 초고강도 콘크리트의 내화성능 평가 (An Evaluation of Fire Resistance Performance for Fiber-Mixed Ultra High Strength Concrete on Field application)

  • 최경철;김규용;이태규;민충식;구경모;신경수
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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    • pp.33-36
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    • 2011
  • Recently, It has increased to use ultra high strength concrete. It is effective to mix organic fibers for preventing spalling. But if fiber mixed, flowability of concrete is decreases. The aim of this study is to evaluation of fire resistance performance for fiber-mixed ultra high strength concrete on field application. As a result, flowability of nylon fiber mixed concrete is better than polyethylene fiber mixed. In non-fiber and polyethylene fiber mixed concrete, spalling occurred. And strain converged at 0.004. Also, residual strength could not evaluate. Nylon fiber mixed concrete is effective to prevent spalling. And it remians 50% residual strength compare with compressive strength at room temperature.

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ON THE GENERALIZED SET-VALUED MIXED VARIATIONAL INEQUALITIES

  • Zhao, Yali;Liu, Zeqing;Kang, Shin-Min
    • 대한수학회논문집
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    • 제18권3호
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    • pp.459-468
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    • 2003
  • In this paper, we introduce and study a new class of the generalized set-valued mixed variational inequalities. Using the resolvent operator technique, we construct a new iterative algorithm for solving this class of the generalized set-valued mixed variational inequalities. We prove the existence of solutions for the generalized set-valued mixed variational inequalities and the convergence of the iterative sequences generated by the algorithm.

레미콘 슬러지의 인공골재로서의 재활용 연구 (Recycling of Ready Mixed Concrete Sludge as artificial aggregate)

  • 문경주;이양수;백명종;소양섭
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
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    • pp.167-172
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    • 1998
  • The purpose of this study is recycling of ready mixed concrete sludge as artificial aggregate by product technique of artificial aggregate in the normal temerature. For the qulity test of artificial aggregate using ready mixed concrete sludge, it is tested in the various aspect. Therefor, Quality of artificil aggregate is suitable as coarse aggregate except absoption, abrasion. For the application of aggregate in cement concrete, Coarse aggregate are replaced with artificial aggregate using ready mixed concrete sludge 100% of volume. The results of test shown that the artificial aggregate using ready mixed concrete sludge could be used replacement of coarse aggregate in cement concrete.

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AN EFFICIENT IMPLEMENTATION OF BDM MIXED METHODS FOR SECOND ORDER ELLIPTIC PROBLEMS

  • Kim, J.H.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제7권2호
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    • pp.95-111
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    • 2003
  • BDM mixed methods are obtained for a good approximation of velocity for flow equations. In this paper, we study an implementation issue of solving the algebraic system arising from the BDM mixed finite elements. First we discuss post-processing based on the use of Lagrange multipliers to enforce interelement continuity. Furthermore, we establish an equivalence between given mixed methods and projection finite element methods developed by Chen. Finally, we present the implementation of the first order BDM on rectangular grids and show it is as simple as solving the pressure equation.

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ZrO2의 혼합방법 차이가 ZTA의 기계적 물성에 미치는 영향 (Effect of Difference in Mixing Methods of Zirconia on Mechanical Properties of ZTA)

  • 손정호
    • 한국재료학회지
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    • 제23권11호
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    • pp.625-630
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    • 2013
  • In this study, intermediate-mixed powders were prepared by loading zirconia powders initially in a ball-mill jar and loading alumina powders afterward; the initial-mixed powders were produced by loading zirconia and alumina powders together in the ball-mill jar. The effect of such differences in mixing method on the mechanical properties was investigated. In intermediate-mixed powders, the volume fraction of large particles slightly increased and, simultaneously, zirconia particles formed agglomerates that, due to early ball-mill loading of the zirconia powders only, were more dispersed than were the initial-mixed powders. For the intermediate-mixed powders, zirconia agglomerates were destroyed more quickly than were initial-mixed powders, so the number of dispersed zirconia particles rose and the inhibitory effect of densification due to the addition of a second phase was more obvious. In the microstructure of intermediate-mixed powders, zirconia grains were homogeneously dispersed and grain growth by coalescence was found to occur with increasing sintering temperature. For the initial-mixed powders, large zirconia grains formed by localized early-densification on the inside contacts of some zirconia agglomerates were observed in the early stages of sintering. The intermediate-mixed powders had slightly lower hardness values as a whole but higher fracture toughness compared to that of the initial-mixed powders.

대체연료로서 가솔린-메타놀 혼합연료에 의한 가솔린 기관성능과 배출오염물에 관한 연구 (A study on engine performances and exhaust emissions using gasoline-methanol as an alternative fuel)

  • 김희철;용기중
    • 오토저널
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    • 제3권2호
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    • pp.18-26
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    • 1981
  • The purpose of this paper is to study the possibility of practical use of gasoline-methanol mixed fuel as an alternative fuel of gasoline engines in the light of engine performances and harmful exhaust emissions as well as mixings and separations of the mixed fuels. When the methanol of 99.8% purity is mixed with super or regular gasoline available on the market today, the experimental results obtained without modifying carburetor in this study are as follows; 1.The separation ratio depends upon the gasoline-methanol mixing ratio only, regardless of fuel temperature and fuel additives for preventing separation of phase. 2.The critical absorption ratio is affected by the gasoline-methanol mixing ratio, its temperature and the quantity of fuel additives. 3.Concerning the distillation temperature, the initial point of all sorts of fuels is almost same,but 10% point and 35-60% point of mixed fuels are lower than those of gasoline only. 4.In case of throttle valve opening set, engine output using the mixed fuels is decreased compared to gasoline, but thermal efficiency is increased as a consequence of decreasing specific energy consumption. 5.In case of fixed load test, thermal efficiency is increased at low engine speed even under low part-load as well as under comparatively high part-load including full load. 6.CO and NOx emissions are reduced remarkably with the mixed fuels.

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섬유 보강 혼합토의 워커빌리티 특성 (Workability Characteristics of Fiber Mixed Soil)

  • 송규복;이상호
    • 한국농공학회논문집
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    • 제58권1호
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    • pp.53-59
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    • 2016
  • This study was conducted by the slump test and the consistency test of the fiber mixed soil which is soil reinforced with fiber as a reinforced material to investigate and estimate the difficulty degree of work and the proper water content. So I would like to present the fundamental data that establishes the work standard of the fiber mixed soil. In conclusion, in this study the slump value of the fiber mixed soil increases over-all according to the increase of the water content although it has a little difference of the increase range and it is smaller than one of the soil. It is estimated that the aggregating and throwing work of the fiber mixed soil would be fine when it has the about 25 % water content and the wall and floor plastering work is the about 30 % ~ 35 % and the flowing and pouring work is the about 40 % water content as well as the mold compacting work is the about 20 %. There is no decreasing of the workability when the soil is reinforced by the fiber because the workability characteristics of the fiber mixed soil is similar to the one of the soil. Therefore, It is estimated that using the fiber as a reinforced material of soil would be appropriate for the construction.

일본 공동체복합지원시설의 복합화 유형과 공간에 관한 연구 (A Study on the Complex type & Space Character of Japanese Community Mixed-support Facility)

  • 김수미;김문덕;서수미
    • 한국주거학회논문집
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    • 제20권2호
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    • pp.11-18
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    • 2009
  • After 2004, as the community mixed-support facility in Japan was admitted as a private business of public facilities based on the Special Law for Urban Regeneration, the community mixed-support facilities in Japan are developed into various types with the view of the urban regeneration and urban renewal, more different point of view, and a tendency of establishment of the community facility has been considerably changed for the past twenty years. The reasons of the change are the social demand for the reformation of facility and the modification of subsidy constitution according to the establishment of equal facility. Some examples of that are the construction of lifelong education community and the change into a equivalent society between male and female and the adjusting to the aging and the welfare society and the social situation of more consumption recently, and in order to emerge from former building system, new facilities related to the contents are being expanded. The complex of the community mixed-support facility has an advantage in that it supplies the services for the complex of the community mixed-support facility, constitutes the communal character and the sense of solidarity among residents and can lead the development of region through the exchange of regional information. Through the Japanese community mixed-support facility which has many cases of it, this study would recognize the suggestion, the feature of it and examine the complex types.

사면(斜面) 녹화용(綠化用) 외래초종(外來草種)의 혼파조합(混播組合)에 관(關)한 연구(硏究) (A Study on the Mixed-Seeding Rates of Exotic Grasses for Slope Revegetation Measures)

  • 전기성;우보명
    • 한국환경복원기술학회지
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    • 제1권1호
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    • pp.102-109
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    • 1998
  • This study was conducted to find out the growth characteristic of mixed-seeding in the grasses for slope revegetation measures. Seeding treatment with six combination types of five grasses used for this experiment such as orchardgrass(Dactylis glomerata 'Potomac'), perennial ryegrass(Lolium perenne 'Manhattan'), tall fescue(Festuca arundinacea 'Jaguar'), kentucky bluegrass(Poa pratensis 'Majestic') and weeping lovegrass(Eragrostis curvula). The growth of orchardgrass, perennial ryegrass and tall fescue were good on mixed-seeding condition in case of number of individuals, heights and coverages at this experiment. These plants will useful for revegetation measures mixed-seeding, but weeping love grass and kentucky bluegrass did not show a desirable growth in mixed-seeding condition, and these plant prefered mixed seeding to single seeding. Regeneration percents of orchardgrass, perennial ryegrass and tall fescue were higher than that of weeping love grass and kentucky bluegrass, and coverage kept on good condition through one year after seeding, therefore, these plants will effective for initial stage revegetation measures.

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죽엽과 연잎 분말을 첨가한 밀 복합분의 물성에 관한 연구 (Study on the Rheological Characteristics of the Mixed Wheat Flour Containing Bamboo and Lotus Leaf Powder)

  • 황성연;오금자;강근옥
    • 한국식생활문화학회지
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    • 제29권4호
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    • pp.355-363
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    • 2014
  • The purpose of this study was to investigate the rheological characteristics of medium wheat flour mixed with bamboo leaf and lotus leaf powders. Rheological properties of the mixed flours were tested based on falling number, color, RVA, farinogram, and rheofermentometer analyses. Falling numbers increased with addition of bamboo leaf and lotus leaf powders. The L values of all mixed flours were less than that of control. The 1% mixed flour sample containing bamboo leaf and lotus leaf powders was not significantly different from 3% mixed flour. The a values of the mixed flour decreased as bamboo and lotus powders increased, whereas b values increased. Addition of bamboo leaf and lotus leaf powders to flour reduced peak viscosity, holding strength, and final viscosity. The set back values of mixed wheat flour containing bamboo leaf powder were lower than those of mixed wheat flour containing lotus leaf powder, suggesting that bamboo leaf powder suppressed retrogradation of flour compared to lotus leaf powder. In the farinogram, the water absorption and consistency of the flours containing bamboo and lotus leaf powders increased, whereas development time and stability decreased. The fermentation time of dough with lotus leaf powder was less than that of dough with bamboo leaf powder.