• Title, Summary, Keyword: mixing time

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An Effect on the Properties of Antiwashout Underwater Concrete by mixing time and mixing quantity (배합시간과 배합량이 수중불분리성 콘크리트의 특성에 미치는 영향)

  • 박세인;김동명;김종수;김명식
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.345-350
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    • 2000
  • The objective of this study makes investigation into the effect on the properties of underwater antiwashout concrete. which is followed by mixing time and mixing quantity. There is an tendency that (the compressive strength of underwater antiwashout concrete made and cured in fresh water or sea water) is increase when dry mixing time, mixing quantity, total mixing time is increase as unit weight grows. The difference of compressive strength (in case of no dry mixing time and 60 second) is averagely 46.8kgf/㎠ in the fresh water and 35.6kgf/㎠ in sea water. it's considered that dry mixing is dispersed by underwater antiwashout admixture.

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Effects of Mixing Speed and Time on the Dynamic Viscoelasticity of Dough and the Baking Properties of Gluten-Free Rice Bread (교반 조건에 따른 Gluten-Free 쌀빵 반죽의 동적점탄성과 제빵 특성)

  • Kim, Sang Sook;Chung, Hae Young
    • The Korean Journal of Food And Nutrition
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    • v.28 no.6
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    • pp.1011-1018
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    • 2015
  • The effects of mixing speed (3, 6 and 10 speed) and time (2, 5 and 10 min) on the dynamic viscoelasticity of dough and the baking properties of gluten-free rice bread were investigated. The specific gravity of the dough was not affected by the mixing speed and time before and after fermentation. The elasticity (G') and viscosity (G") of the dough increased and the tan ${\delta}$ (G"/G') decreased with higher mixing speeds and longer mixing times. The specific volume of the gluten-free rice bread was affected by the mixing time in response surface methodology (RSM). The hardness of the gluten-free rice bread showed a decreasing trend as the specific volume for the gluten-free rice bread increased. The appearance of the gluten-free rice bread was symmetrical at high mixing speeds and long mixing times. Overall results indicated that the quality of gluten-free rice bread could be improved by controlling the mixing speeds and mixing times for the dough.

A Mixing Time Measurement by a Conductivity Method in a Continuous Flow Stirred Tank (電氣傳導度 測定에 依한 連續流 攪拌槽의 混合時間 測定)

  • Kang, Woong-Ki
    • Journal of the Korean Chemical Society
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    • v.6 no.2
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    • pp.130-132
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    • 1962
  • A new method of evaluating the mixing time in the continuous flow stirred tank is herein proposed. Experimental results to test the concept are also presented.The mixing time is defined as the time interval between the injection of a slug of an electrolyte solution into the tank and the moment at which an essentially straight line begins on a plot of the conductivity of effluent versus time.The proposed method of measuring the mixing time is valid even for the low mixing time (5 seconds) and the results obtained agree well with previous work, where the mixing time measurements were carried out by the injection of a dye into the feed stream.

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The Effect of Viscosity of Natural Rubber on Incorporation Rate of Carbon Black in The Mixing (배합중 카본블랙 혼입속도에 천연고무 점도가 미치는 영향)

  • Kang, Yong-Gu;Han, Shin;Lee, Kye-Jung;Ryu, Dong-Wan;Park, Chan-Young
    • Journal of the Korean Society of Industry Convergence
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    • v.2 no.1
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    • pp.97-103
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    • 1999
  • The power curve during rubber mixing presents useful information for the understanding of rubber mixing process, because the power curve is determined the mixing state of rubber at the point. The time to the second peak on the power curve is known as carbon black incorporation time, BIT. This study gets the quantity relationship of BIT and viscosity of natural rubber, so by determining the mixing time of the compound on the ground of viscosity of the raw rubber. The mixing with natural rubber and carbon black is examined for various grade natural rubbers, encompassing a wide range of Mooney viscosity. Alter smoothing the mixing power curve using a polynomial, the carbon black incorporation time, BIT, was determined time to second power peak on the curve, The BIT's versus specific values on Mooney viscometer test curve show a linear relation, Especially, the peak of initial maximum torque on Mooney viscometer curve, PMT, is most relevant property relating to the BIT. PMT is useful index for determined optimum mixing time, To apply this results at the mixing, we effectively control the natural rubber mixing but can also know the grading of natural rubber upon processability.

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Characteristics of Micro Floc in a Rapid Mixing Step at Different Coagulant Dose (급속혼화공정에서 응집제 주입률에 따른 미세입자의 성장특성)

  • Jun, Hang-Bae;Park, Sang-Min;Park, Noh-Back;Jung, Kyung-Su
    • Journal of Korean Society of Water and Wastewater
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    • v.21 no.2
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    • pp.243-252
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    • 2007
  • Effects of alum dosage on the particle growth were investigated by monitoring particle counts in a rapid mixing process. Kaolin was used for turbid water sample and several other chemicals were added to adjust pH and ionic strength. The range of velocity gradient and mixing time applied for rapid mixing were $200{\sim}300sec^{-1}$ and 30~180 sec, respectively. Particle distribution in the synthetic water sample was close to the natural water where their turbidity was same. The number of particles in the range of $10.0{\sim}12.0{\mu}m$ increased rapidly with rapid mixing time at alum dose of 20mg/L, however, the number of $8.0{\sim}9.0{\mu}m$ particles increased at alum dose of 50mg/L. The number of $14.0{\sim}25.0{\mu}m$ particles at alum dose of 20mg/L was 10 times higher than them at alum dose of 50mg/L. Dominant particle growth was monitored at the lower alum dose than the optimum dose from a jar test at an extended rapid mixing time(about 120 sec). The number of $8.0{\sim}14.0{\mu}m$ particles was lower both at a higher alum doses and higher G values. At G value of $200sec^{-1}$ and at alum dose of 10-20mg/L, residual turbidity was lower as the mixing time increased. But at alum dose above 40mg/L and at same G value, lower residual turbidity occurred in a short rapid mixing time. Low residual turbidity at G value of $300sec^{-1}$ occurred both at lower alum doses and at shorter mixing time comparing to the results at G value of $200sec^{-1}$.

The study on the mixing character of synthetic molding sand by power change (혼사전력 변화에 의한 합성사의 혼련특성에 관한 연구)

  • Kim, Young-Sik;Jeong, Jeong-Yeon;Lee, Jong-Nam
    • Journal of Korea Foundry Society
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    • v.4 no.1
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    • pp.12-20
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    • 1984
  • In order to investigate the effect of size of sand grains, bentonite content and moisture on mixing power, standard mixing power, permeability, green compressive strength and green mold hardness were measured with mixing time, and also coated layer of mixed sand with time was observed by optical microscope and scanning electron microscope. From this experiment, the results were summarized as follows. 1. Mixing power increased as size of sand grains decreased. 2. Mixing power increased gradually as bentonite content increased and in particular, increased rapidly in 7-10% bentonite. 3. Mixing power increased as moisture content decreased. 4. The mixing time required to get the optimum mixing power decreased as moisture content and grain size increased, but increased as bentonite content increased.

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Thermally-Induced Atomic Mixing at the Interface of Cu and Polyimide

  • Koh, Seok-Keun;Choi, Won-Kook;Song, Seok-Kyun;Kook D. Pae;Jung, Hyung-Jin
    • Journal of the Korean Vacuum Society
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    • v.3 no.3
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    • pp.316-321
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    • 1994
  • Rate of mixing of Cu particles to polyimide substrate at interfaces under different thermal treatments was analyzed by Rutherford Backscattering spectroscopy using 2.0 MeV He+ ions. T he mixing rate was a function of annealing temperature and time and was constant at afioxed temperature. The amount of mixing increased linearly with time and the mixing rate increased with temperature. The activation energy for interface mixing between Cu and polyimide was 2.6 kcal/mol. The X-ray studies showed the Cu(111) plane peak changed with annealing time at fixed temperature. The mixing of Cu to polyimide was explained with segmental motion of PI chain and with interaction between functional group of the chain and metal electron donor. The comparisons were made bewteen the mixing induced by ion irradiation and by thermal treatment. The various factors affecting the interface mixing are discussed.

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Effects of hydrodynamics and coagulant doses on particle aggregation during a rapid mixing

  • Park, Sang-Min;Heo, Tae-Young;Park, Jun-Gyu;Jun, Hang-Bae
    • Environmental Engineering Research
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    • v.21 no.4
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    • pp.365-372
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    • 2016
  • The effects of hydrodynamics and alum dose on particle growth were investigated by monitoring particle counts in a rapid mixing process. Experiments were performed to measure the particle growth and breakup under various conditions. The rapid mixing scheme consisted of the following operating parameters: Velocity gradient (G) ($200-300s^{-1}$), alum dose (10-50 mg/L) and mixing time (30-180 s). The Poisson regression model was applied to assess the effects of the doses and velocity gradient with mixing time. The mechanism for the growth and breakup of particles was elucidated. An increase in alum dose was found to accelerate the particle count reduction. The particle count at a G value of $200s^{-1}$ decreased more rapidly than those at $300s^{-1}$. The growth and breakup of larger particles were more clearly observed at higher alum doses. Variations of particles due to aggregation and breakup of micro-flocs in rapid mixing step were interactively affected by G, mixing time and alum dose. Micro-flocculation played an important role in a rapid mixing process.

A Study on the Homogeneity of Powder Mixture (분말약품 혼합의 균일성에 관한 연구)

  • 김길수;이민화
    • YAKHAK HOEJI
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    • v.21 no.2
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    • pp.95-100
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    • 1977
  • The effects of the particle size on the homogeneity of mixing and segregation of caffeine-lactose (1:99) mixture were studied. Using the two kinds of caffein, milled and unmilled caffein, V-type blender, the degree of mixing according to the particle size was predicted and the experiment on the change of mixedness by mixing time was carried out by the method derived from mixing index theory by Poole et al. and Hersey. the results could be summarized as follows; (1) The homogeneity of mixing was greatly affected by the particle size and the particle size should be reduced to the adepuate level to attain the desirable mixedness. (2) The homogeneity was not proportional to the mixing time and optimum mixing time for caffein-lactose was about 10 minutes. (3) Segregation tendency was increased by the particle size increase and greatly affected by the flow time in the segregation cell.

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Numerical analysis of internal flow and mixing performance in polymer extruder I: single screw element

  • Kim, Nak-Soo;Kim, Hong-Bum;Lee, Jae-Wook
    • Korea-Australia Rheology Journal
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    • v.18 no.3
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    • pp.143-151
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    • 2006
  • We analyzed the non-Newtonian and non-isothermal flow in a single screw extruder system and investigated the mixing performance with respect to the screw speed and the screw pitch. The viscosity of polymer melt was described with Carreau-Yasuda model. The mixing performance was computed numerically by tracking the motions of particles in the screw element system. The extent of mixing was characterized in terms of the deformation rate, the residence time distribution, and the strain. The results revealed that the high screw speed reduces the residence time but increases the deformation rate while the small screw pitch increases the residence time. It is concluded that the high screw speed increases the dispersive mixing performance and the small screw pitch increases the distributive mixing performance.