• Title/Summary/Keyword: 점성비

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Study on Mock-up Properties of Concrete using Blast Furnace Slag and Recycled Aggregate (고로슬래그와 재생골재를 사용한 콘크리트의 실물대 특성에 관한 연구)

  • Park, Hyun;Han, Da-Hee;Park, Moo-Young;Kim, Woo-Jae;Lee, Young-Do;Jung, Sang-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.789-792
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    • 2008
  • Blast furnace slag doesn't have self-hydraulicity and it needs stimulants such as alkali to hydrate. Therefore using recycled aggregates erupted calcium hydroxides and blast furnace slag acquiring alkali stimulate could make a complementarily use of a recycling architectural material possible. In this study, we have discussed about characters of blast furnace slag and recycled aggregate firstly, and make recycled aggregate mortar and concrete using blast furnace slag for the experiment. The experiment is about mortar and concrete using recycled aggregate as a substitutional material of blast furnace slag. In this experiment, I replace blast furnace slag and aggregate with recycled aggregate. Conclusions through the test results analysis are as follows. And then, we added field experiment using concrete with composited materials.

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Studies on the Viscometric Behavior of Mayonnaise (마요네즈의 점성(粘性)에 관(關)한 연구(硏究))

  • Lee, Yung-Yup
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.15 no.2
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    • pp.119-127
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    • 1986
  • The rheological properties of mayonnaise were studied with cylindrindrical viscometer. It was observed that mayonnaise showed pseudoplastic behavior, yield stress and time dependent characteristics. In the initial period of shear time, the decay of viscosity of mayonnaise was followed by a second-order kinetic equation. The influence of temperature on viscosity could be described by Arrhenius equation. The apparent viscosity of mayonnaise markedly increased with an rise in the concentration of egg yolk; and the emulsion was most stable at the concentration of 12%. At the concentration of $65{\sim}75%$ oil, the apparent viscosity was increased; the maximum value was reached at 75% oil, and above 75% oil, the remarkable decreased was observed. The size of oil drops was decreased with an increase in oil concentration of 75% oil. The apparent viscosity of mayonnaise was increased with an rise in water contents, while being decreased with one in the concentration of vinegar.

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The Influence of Plasma Surface Modification on Frictional Property of Natural Rubber Vulcanizates

  • Nah, C.;Kim, D.H.;Mathew, G.;Jeon, D.J.;Jurkowski, B.;Jurkowska, B.
    • Elastomers and Composites
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    • v.39 no.1
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    • pp.12-22
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    • 2004
  • The plasma surface modification of natural rubber vulcanizate was carried out using chlorodifluoromethane in a radio-frequency (13.56 MHz) electrodeless bell type plasma reactor. The modification was qualitatively assessed by Fourier transform infrared spectroscopy. The frictional force of the plasma-treated surface was found to decrease with the time of plasma treatment. An increase in the surface polarity, as evidenced by the decrease in contact angle of a sessile drop of water and ethylene glycol on the natural rubber vulcanizate surface, was noted with the plasma modification. In the case of similar plasma treatment of glass surface, only a reduction in the polarity was observed. The use of geometric and harmonic mean methods was found to be useful to evaluate the London dispersive and specific components of surface free energy. Irrespective of the method used for evaluation, an increasing trend in the surface free energy was noted with increasing plasma treatment time. However, the harmonic mean method yielded comparatively higher values of surface free energy than the geometric mean method. The plasma surface modification was found to vary the frictional coefficient by influencing the interfacial, hysteresis and viscous components of friction in opposing dual manners.

Sensory Characteristics of Dressing made with gugija(Lycium chinense) (구기자를 첨가한 드레싱의 관능적 특성)

  • Yang, Jung-Su;Kim, Hyun-Ah;Song, Chung-Rak
    • Culinary science and hospitality research
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    • v.21 no.5
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    • pp.59-71
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    • 2015
  • Considering sensory characteristics Herbal mayonnaise, Herbal yoghurt and Herbal italia dressing with extracts of gugija(Lycium chinense) as additives, this study attempts to develop dressing that meets preference of people of Korea through sensory characteristics. The test results of moisture, pH, color, viscosity and sensory testing dressings with 10%, 15% and 20% extracts of gugija(Lycium chinense) as follow; Moisture contents increase in proportion to addition of the extracts of gugija(Lycium chinense). Sugar contents decrease in proportion to addition of the extracts of gugija(Lycium chinense). Also pH values of dressings increase with addition of gugija(Lycium chinense) extracts. Lower Hunter L values are observed from the dressings with the extracts of gugija(Lycium chinense) than control groups. Higher Hunter a values are observed from the dressing with gugija(Lycium chinense) extracts, whereas lower Hunter b values are observed from the dressings with gugija(Lycium chinense) extracts. The lower viscosity values are observed with addition of the extracts of gugija(Lycium chinense)s than control groups. For mayonnaise dressing, ML3 with 20% gugija(Lycium chinense) extract(MC1) mark highest overall preference. For yoghurt dressing, YL3 with 20% gugija(Lycium chinense) extract show highest overall preference. For Italian dressing, IL3 with 20% gugija(Lycium chinense) extract impart highest Overall preference. According to the results of this study, the dressings with the extracts of gugija(Lycium chinense) are preferred in color, flavor, taste and overall preference to control groups. This study might provide significant data for developing dressings with herbal medicine match with dishes to meet the needs for health of our contemporaries.

A Numerical Study of Tumble Effect on Spray/wall Impingement in the D. I. Engines (직접분사식 엔진내의 분무/벽 충돌 현상에서 텀블 효과에 관한 연구)

  • Chae, Soo;Yang, Hyup;Ryou, Su-Yeal;Ryou, Hong-Sun
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.5
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    • pp.45-57
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    • 2002
  • In this paper, the results gained by applying many impingement models to the cylinder and flat plate were analyzed in comparison with the experimental data to study a spray/wall interaction phenomena. To begin with, the behavior of spray injected normal to the wall was analysed using three different impingement models ; Naber and Reitz model(NR model), Watkins and Wang model(WW model) and Park and Watkins model(PW model) in the present calculation. The results obtained from these models were compared with experimental data of Katsura et. al. The results indicated that PW model was in better agreement with experimental data than the NR and WW model. Also f3r spray injected at 30DEG , the result of three models were compared with experimental data of Fujimoto et. al. The results showed that m model overpredicted the penetration in the radial direction because this model was based on the inviscid jet analogy. WW model did not predicted the radius and height of the wall spray effectively. It might be thought that this discrepancy was due to the lack of consideration of spray film velocity occurred at impingement site. The result of PW model agrees with the experimental data as time goes on. In particular, a height of the spray droplets was predicted more closely to the experimental data than the other two models. The results of PW model in which the spray droplets were distributed densely around the edge of droplet distribution shaped in a circle had an agreement with the experimental data of Fujimoto et. al. Therefore, it was concluded that PW model performed better than M and WW model for prediction of spray behavior. The numerical calculation using PW model performed to the cylinder similar to the real shape of DI engine. The results showed that vortex strength near the wall in the cylinder was stronger than that in the case of flat plate. Contrary to the flat plat, an existence of the side wall in the cylinder caused the tangential velocity component to be reduced and the normal velocity component to be increased. The flow tends to rotate to the inside of cylinder going upward to the right side wall of cylinder gradually as time passes. Also, the results showed that as the spray angle increases, the gas velocity distribution and the tumble flow seemed to be formed widely.

Time-dependent Evolution of Accretion Disk Mass in a Black Hole Microquasar Candidate A0620-00 (블랙홀 마이크로퀘이사 후보 A0620-00의 강착원반 질량의 시간적 진화)

  • Kim, Soon-Wook
    • Journal of the Korean earth science society
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    • v.29 no.7
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    • pp.579-585
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    • 2008
  • The time-dependent evolution of disk mass for outburst limit cycle in a black hole microquasar is calculated based on the non-linear hydrodynamic model of thermally unstable accretion disk. The physical parameters such as black hole mass, disk size and mass transfer rate are adopted to reproduce the historical 1975 outburst observed in a prototype black hole X-ray nova A0620-00. The time-dependent effect of irradiation from the central hot region to the disk is considered in two ways: direct irradiation and indirect irradiation reflected from hot accretion flow above the disk. The accretion disk thermal instability model can account for the bolometric luminosity appropriate to typical characteristics of system luminosity observed in X-ray transients during the whole cycle of the outburst evolution. The maximum mass of the accretion disk, ${\sim}4.03{\times}10^{24}g$, is achieved at the ignition of an outburst, and the minimum value, ${\sim}8.54{\times}10^{23}g$, is reached during the cooling decay to quiescence. The disk mass varies ${\sim}5$ times during outburst limit cycle.

A Fluidity Experiment of Pre-Mix Cement for Dispersibility Improvement of Mineral Admixture (광물질 혼화재의 분산성 향상을 위한 프리믹스 시멘트의 유동성 실험)

  • Han, Cheon-Goo;Lee, Hai-Ill;Noh, Sang-Kyun;Kim, Ki-Hoon
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.4 no.2
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    • pp.90-96
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    • 2009
  • The high rising building construction makes increasing the requirement of high strength concrete. Especially, the workability analysis is related with dispersion of admixture such as SF for improving strength and FA, BS for reducing construction cost and improving durability of Ultra High Strength Concrete which has over 100 MPa of compressive strength is very important. Precisely, decreases dispersion because of lumping situation of each admixture and it causes the workability of admixture is decreased. Therefore, the workability of cement paste is tested for analyze effects of pre-mixed cement for solving those problems with it to this research. The summary of the results are like below. First of all, OBS is increasing workability more than OFS. This result causes that the glassy surface of BS in the OBS is increasing workability and the absorption of admixture of FA in the OFS is decreasing workability. In the case of mixing methods, pre-mixing method is increasing workability more than normal one. This result shows that the normal mixing method is bad dispersion of binders. The other side, the pre-mixing method is good. Furthermore, depending on the mixing time, according to the increasing mixing time such as 30, 60, and 120 seconds, the dispersion of binders and workability turns better.

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Physicochemical Properties and Antioxidant Activity of Extruded Rice Flour with Various Cacao (Theobroma cacao L.) Bean Content (카카오 빈 함량에 따른 쌀 압출성형물의 이화학적 특성 및 항산화 활성)

  • Park, Ju-Yeon;Kim, Young-Ho;Ryu, Gi-Hyung
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.11
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    • pp.1327-1335
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    • 2017
  • This study was carried out to determine the effect of cacao bean addition on the physicochemical properties of extruded rice flour. Rice-based cacao beans (0, 20, 40, 60%) were extruded at a die temperature of $130^{\circ}C$, screw speed of 200 rpm, and moisture content of 25%. As the content of cacao beans increased from 20% to 60%, expansion index decreased, while piece density and specific length increased. The water soluble index and water absorption index of the extrudate increased through extrusion cooking. Lightness decreased as cacao bean content increased while redness increased. As the content of cacao beans increased, paste viscosity decreased. Cold peak viscosity was observed in all extrudates of raw roasted cacao beans. ${\alpha},{\alpha}$-Diphenyl-${\beta}$-picrylhydrazyl (DPPH) radical-scavenging activity increased upon extrusion and cacao bean addition. As content of cacao beans increased, non-roasted cacao beans had higher total phenolic contents than roasted cacao beans. This study showed that addition of cacao beans to extruded rice snack improved antioxidant activity.

Experimental Study on Engineering Characteristic of the Waste Landfill Soil Admixed Linear (폐기물매립지 토사계 혼합 차수재의 공학적 특성에 대한 실험적 연구)

  • Chang, Yongchai;Kim, Jinchun;Jeong, Ogki
    • Journal of the Korean GEO-environmental Society
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    • v.8 no.1
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    • pp.13-20
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    • 2007
  • Leachates resulting from the waste landfill of waste can possibly cause the second pollution, such as the underground water and environmental pollution. Accordingly, Liner layer has been installed in the reclaimed land of waste to block and purify permeation water to and prevent this second pollution. The material used as Liner layer should have water resistance and be less than permeability coefficient of $1{\times}10^{-7}$ cm/sec. As it is very difficult to get this kind of natural clay with low permeability around the field, the suitable way to get the low permeable material is to use blend with good watertighness by mixing it with natural soil which is spread in the site. While this mixed soil, which can resist water, is commonly used in the site, namely, bentonite and MCG cementious mateiral mixed soil, which is widely used as Liner layer in the reclaimed land of waste, is recognized in Liner and durability. The study was performed to find the effect of additive of the bottom liner in the waste landfill. The aim of this paper is to explain of the field application examples as well as the data of experimental research with the engineering properties of Liner layer of the reclaimed land.

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Thermal Flow Characteristics of a Hybrid Plant Factory with Multi-layer Cultivation Shelves (다층 재배선반을 갖는 하이브리드 식물공장의 열유동 특성)

  • Yoon, Ji-Hwan;Ryu, Bong-Jo;Kim, Youngshik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7990-8000
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    • 2015
  • Plant factories are plant cultivation systems which produce farm products uniformly under the controlled environmental condition regardless of seasons and places. Thermal flow in the plant factory is an important parameter in cultivating plants. In this research, we study thermal flow characteristics for a hybrid plant factory with multi-layer cultivation shelves using computer simulation techniques. In order to obtain numerical solutions for thermal flow characteristics, a finite volume method was applied. We consider a low-Reynolds-number ${\kappa}-{\epsilon}$ turbulence model, incompressible viscous flows, and pressure boundary conditions for numerical simulation. Commercial software Solid Works Flow Simulation is then used to investigate characteristics of thermal flows in the plant factory applying several different inflow air velocities and arrangements of cultivation shelves. From numerical analysis results, we found that temperatures in cultivation shelves were uniformly distributed for Case 3 when the inflow air velocity was 1.6 m/s by using a blower in the plant factory. However in Case 1 lower temperature distributions were observed in test beds, TB2 and TB3, which indicated that additional temperature control efforts would be required. Average shelf temperature increased by $3^{\circ}C$ using artificial light source (DYLED47) with 50% blue and 50% red LED ratios. Korea Academia-Industrial cooperation Society.