• 한국건설순환자원학회논문집
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• 제2권4호
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• pp.345-353
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• 2014

This study was evaluated influence of fluidity properties according to basalt fiber and high volume fly ash in the mortar level, as part of a basic study for development of fiber reinforced concrete using basalt fiber and high volume fly ash. In the first step, it was evaluated that fluidity properties of mortar according to replacement ratio 6 level of fly ash(10, 20, 30, 40, 50 and 60mass%) and fluidity properties of mortar according to content 5 levels of SP(1.3, 1.5, 1.7, 1.9 and 2.1%) and content 5 levels of VA(0.2, 0.4, 0.6, 0.8 and 1.0%) for dispersion of the basalt fiber, in the second step, it was evaluated that fluidity properties of mortar using High-volume fly ash (50mass%) on 3 levels of basalt fiber length (6, 20 and 30mm). Results of assessment, if after a fiber mixed, it showed that viscosity agent is more effective to improve the fluidity and fiber dispersion than superplasticizer, high volume fly ash (50%) applying the mixing, due to three properties of fly ash, showed that the improved fiber dispersibility and flow improvement.

• 콘크리트학회지
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• 제10권6호
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• pp.313-323
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• 1998

고성능 AE감수제를 사용한 콘크리트의 유동성 유지성능은 고성능 AE감수제의 주성분 및 사용량, 사용방법과 광물질 혼화재의 종류 및 혼합률 등에 따라서 영향을 받는다. 본 연구에서는 주성분이 다른 3종류의 고성능 AE감수제의 사용량과 사용방법을 변화시키고 분말도가 다른 3종류의 고로슬래그 미분말을 활용하여 시멘트풀, 모르터 및 콘크리트의 유동성 유지성능과 강도특성을 비교고찰하여 효율적인 유동성 유지방안을 제시하고자 하였다. 연구결과 고성능AE감수제를 사용한 콘크리트의 유동성 유지성능은 경과시간에 따른 시멘트 입자의 응집성과 밀접한 상관성이 있으며 나프탈린계 고성능 AE감수제의 사용과 고로슬래그 미분말의 분말도가 작고 혼합률이 클수록 모르터 및 콘크리트의유동성 유지성능이 현저히 향상되었다. 한편 고성능AE감수제의 종류에 관계없이 30분후 첨가방법이 유동성 유지성능 및 강도향상에 있어서 일석이조의 좋은 성과가 있었다.

• Journal of Microbiology and Biotechnology
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• 제25권2호
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• pp.162-173
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• 2015

The cellular fatty acid composition is important for metabolic plasticity in Rhodobacter sphaeroides. We explored the effects of changing the cellular ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs) in R. sphaeroides by overexpressing several key fatty acid biosynthetic enzymes through the use of expression plasmid pRK415. Bacteria containing the plasmid pRKfabI₁ with the fabI₁ gene that encodes enoyl-acyl carrier protein (ACP) reductase showed a reduction in the cellular UFA to SFA ratio from 4 (80% UFA) to 2 (65% UFA) and had decreased membrane fluidity and reduced cell growth. Additionally, the ratio of UFA to SFA of the chromatophore vesicles from pRKfabI₁-containing cells was similarly lowered, and the cell had decreased levels of light-harvesting complexes, but no change in intracytoplasmic membrane (ICM) content or photosynthetic (PS) gene expression. Both inhibition of enoyl-ACP reductase with diazaborine and addition of exogenous UFA restored membrane fluidity, cell growth, and the UFA to SFA ratio to wild-type levels in this strain. R. sphaeroides containing the pRKfabB plasmid with the fabB gene that encodes the enzyme β-ketoacyl-ACP synthase I exhibited an increased UFA to SFA ratio from 4 (80% UFA) to 9 (90% UFA), but showed no change in membrane fluidity or growth rate relative to control cells. Thus, membrane fluidity in R. sphaeroides remains fairly unchanged when membrane UFA levels are between 80% and 90%, whereas membrane fluidity, cell growth, and cellular composition are affected when UFA levels are below 80%.

• 한국지열·수열에너지학회논문집
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• 제8권2호
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• pp.1-8
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• 2012

The G-class cement is usually used for geothermal well grouting to protect a steel casing which is equipped in a geothermal well to transfer geothermal water from deep subsurface to ground surface. In geothermal grouting process, obtaining appropriate fluidity is extremely important in order to fill cement grout flawlessly. In this paper, a series of the V-funnel and Slump Flow test was performed on both of the Portland cement and the G-class cement in order to compare fluidity and filling ability of those kind of cements. In the result of V-funnel test, the fluidity of G-class cement was evaluated much better than the Portland cement at the water/cement ratio of 0.8. In the case of Slump Flow test, the fluidity of G- class cement was estimated slightly better than the Portland cement at both the water/cement ratio of 0.55 and 0.8. Even though the initial fluidity and filling ability of G-class cement were relatively higher than the Portland cement, the results could be considerably changed with time. The results show that the fluidity and filling ability for geothermal well cementation can be properly controlled with water content and additives for adverse geothermal well environment.

• 한국건축시공학회지
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• 제22권5호
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• pp.441-450
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• 2022

본 연구에서는 순환자원으로 구성된 비소성 시멘트의 유동성 확보를 위해 감수제의 종류 및 첨가율에 따른 비소성 시멘트 모르타르의 유동성과 강도 특성을 분석하였다. 감수제 첨가에 따른 비소성 시멘트의 유동성은 감수제 첨가비율이 높고 플라이애시 치환 비율이 높을수록 유동성은 향상되는 것으로 나타났다. 특히 폴리카르본산계 감수제 첨가 시 소성 시멘트 모르타르보다 유동성 확보에 유리하며, 비소성 시멘트 모르타르의 적정 유동성 확보와 동시에 강도 확보가 가능한 것으로 판단된다. 또한 감수제 첨가에 따른 비소성 시멘트 모르타르는 고칼슘 애시의 치환 비율이 높고 염기도가 높을수록 반응성이 촉진되는 경향이 있는데 급격한 반응 촉진은 오히려 강도저하를 유발할 수 있으므로 목표한 유동성을 만족하는 범위 내에서 적정 배합조건을 도출하였다.

• 한국주조공학회지
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• 제24권1호
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• pp.34-39
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• 2004

The effects of casting condition and hot melt glue during Lost Foam Casting were investigated on the fluidity of Al alloy melt. The fluidity increased linearly with increasing pouring temperature in thick castings but non-linearly in thin casting due to the difference in main heat flow direction. The metal flow velocity was in range of $0.5{\sim}2.7$ cm/s in no evacuation condition and the minimum value of it was measured after the melt flow through the hot melt barrier. The mold evacuation improved the metal flow velocity by around $0.5{\sim}1$ cm/s. And the reaction zone layer thickness was about 1 cm in no-evacuation conditions but about 0.6 cm in mold evacuation condition of 710 torr due to the easier removal of pyrolsis product of EPS. And hot melt barrier thickness of 0.6 mm increased the reaction zone layer thickness up to about 2.5 cm. The fluidity decreased remarkably with an enlarged thickness of hot melt due to a lot of pyrolysis products.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.63-68
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• 1998

The fluidity of high flowing concrete can be affected by numerous parameters which characterize either the cement of the admixture. The reactivity of a cement as determined by its chemical composition(especially its $C_3$A content), its fineness and its content in sulfates and alkalies obviously plays a key role in rheology of high flowing concrete in fresh state. Specific properties of high range water reducing AE agent used to enhance the workability of high flowing concrete also exert important influence. The purpose of this experimental study is to investigate and analyze the effect of cement and high range water reducing AE agent in fluidity, setting, compressive strength of high flowing concrete. As a result, we found that fluidity of high flowing concrete is affected greatly by kind of cement and high range water reducing AE agent, also, there is harmonic character between high belite cement and polycarbonic acid high range water reducing AE agent.

• Journal of Photoscience
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• 제8권3_4호
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• pp.87-92
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• 2001

Intramolecular excimer formation of 1,3-di(1-pyrenyl)propane (Py-3-Py) and fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) were used to investigate the effects of parathyroid hormone (PTH) on the bulk bilayer fluidity of the plasma membrane vesicles isolated from cultured osteoblasts (OB-PMV). In a dose-dependent manner, rat PTH-(1-34) [rPTH-(1-34)] increased the excimer to monomer fluorescence intensity ratio (I'/I) of Py-3-Py and decreased the anisotropy (r) of DPH in OB-PMV. This indicates that PTH increased both the lateral and rotational diffusion of the probes in OB-PMY. Selective quenching of DPH fluorescence by trinitrophenyl groups was utilized to examine the transbilayer fluidity asymmetry of OB-PMV. The anisotropy, limiting anisotropy, and order parameter of DPH in the inner monolayer were 0.024, 0.032, and 0.062 greater than calculated for the outer monolayer of OB-PMY. Selective quenching of DPH fluorescence by trinitrophenyl groups was also utilized to examine the transbilayer effects of PTH on the fluidity of OB-PMV. rPTH-(1-34) had a greater fluidizing effect on the outer monolayer as compared to the inner monolayer of OB-PMV. Thus, it has been proven that PTH exhibits a selective rather than nonselective fluidizing effect within transbilayer domains of OB-PMV.

• 한국안전학회지
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• 제29권2호
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• pp.18-23
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• 2014

Foam extinguishing agent is widely used for extinguishing combustible liquid fires. Compared to other foam type extinguishing agents, protein foam has relatively low cost and low toxicity and produces stable foam blanket which is excellent in heat resistance and sealability, despite it has weak fluidity. Therefore the study investigated foaming characteristics followed by various factors affecting the fluidity of the protein foam extinguishing agent. The extinguishing characteristics differentiated by the changes in fluidity were also experimented. Foaming performance was compared by measuring the expansion ratio and the 25% drainage time. Moreover, the 25% drainage time and the extinguishing time was compared. The results showed that the 25% drainage time and the expansion ratio were increased as the pressure of nozzle and the concentration of hydrolyzed protein liquid enlarged. However the foaming and extinguishing performance were not improved when the condition exceeded certain level of pressure and concentration. The fastest fire extinguishing condition was the nozzle pressure 4bar with the 85wt.% of concentration of hydrolyzed protein liquid.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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• pp.43-46
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• 2007

This study dealt with the influence of the replacement ratio of rapidly-chilled steel slag on fluidity and compressive strength of unsaturated polyester polymer concretes. The rapidly-chilled steel slag used in this study, a by-product which is produced by refining pig iron during the manufacture of steel, was controled by a air-jet method which rapidly cools substance melted at a high temperature. Experimental results show that fluidity and compressive strength of unsaturated polyester polymer concretes increase with increasing replacement ratio of rapidly-chilled steel slag. Use of rapidly-chilled steel slag was found to be effective for improving fluidity and compressive strength of rapidly-chilled steel slag.