Density Gradient Techniques.

Oster, Gérald; Yamamoto, Masahide

doi:10.1021/cr60223a003

Cited by 151 publications

(65 citation statements)

References 33 publications

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“…This combination reduces major limitations of optical velocity measurements across the interface such as a distortion of the laser sheet and of the scattered light to the camera [28]. However, brilliant techniques have been developed to match the refractive index of two solutions with different densities [29,30]. To avoid double diffusivity phenomena and guarantee the largest possible density ratio between the two fluids, for the case 1 the best combination results in a lighter solution of ethanol and water and a heavier saline solution of Epsom salts and water.…”

Section: Experiments and Techniquesmentioning

confidence: 99%

Steady state model and experiment for an oscillating grid turbulent two-layer stratified flow

2017

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Turbulence generated by an oscillating grid in a two-layer stably stratified system is a classical flow utilised to study various aspects of turbulence in presence of stratification without mean shear.This flow evolves in a quasi-steady state, in which the layer thickness and density difference evolves in a quasi-steady manner due to the large separation of timescales between the turbulence and the setup. We present an extension of the classical setup that enables full steady state conditions and in which the entrainment velocity can be prescribed separately from the Richardson number.We develop a theoretical box-model and show that the model is in good agreement with the experiments. The model allows to predict the transient response of the system for a variety of initial conditions and the imposed steady state. The new setup is necessary to obtain the steady position of the density interface, for example when using advanced optical techniques to measure the small-scale features of turbulence near the interface.

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Section: Experiments and Techniquesmentioning

confidence: 99%

Steady state model and experiment for an oscillating grid turbulent two-layer stratified flow

2017

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“…A density gradient column can be used to that end (Brown et al 1996;Coombs 1981;Oster and Yamamoto 1963;Taylor 1955, 1956), but less expensive techniques are also available. For our experiments, the matching method involved (i) mixing different fluids with a density range close to the PMMA datasheet values and (ii) observing the time needed for the particles to rise or sink.…”

Section: Density Matching Proceduresmentioning

confidence: 99%

Refractive-index and density matching in concentrated particle suspensions: a review

et al. 2010

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Optical measurement techniques such as particle image velocimetry (PIV) and laser Doppler velocimetry (LDV) are now routinely used in experimental fluid mechanics to investigate pure fluids or dilute suspensions. For highly concentrated particle suspensions, material turbidity has long been a substantial impediment to these techniques, which explains why they have been scarcely used so far. A renewed interest has emerged with the development of specific methods combining the use of iso-index suspensions and imaging techniques. This review paper gives a broad overview of recent advances in visualization techniques suited to concentrated particle suspensions. In particular, we show how classic methods such as PIV, LDV, particle tracking velocimetry, and laser induced fluorescence can be adapted to deal with concentrated particle suspensions.

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“…glass tubes. The density gradient was checked by the use of glass balls of lmown density (Oster and Yamamoto 1963). Three different liquid systems were tried, viz.…”

Section: (0) Separation Of Ownponents Of Woolmentioning

confidence: 99%

The Chemical Composition of Wool

Bradbury¹,

Chapman²

1964

Aust. Jnl. Of Bio. Sci.

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SummaryA study is made of the disruption of wool by ultrasonic disintegration and the separation and identification by microscopy of the major components of the fibre. The ultrasonic disintegration process is investigated empirically in order to establish the conditions under which maximum rates of disruption occur. Of a large number of liquids examined it is found, in confirmation of earlier work, that the rate of disintegration of wool is very slow in water but usually increases in amount as the swelling of the fibre increases. The several exceptions to this rule show that there are other factors of secondary importance in determining the rate of disruption. The amount of disruption is sufficient for preparative purposes and increases in amount in the series dimethyl sulphoxide, formic acid, and dichloroacetic acid.Cortical cells, cuticle, and disrupted cortical cells can be separated on the basis of their different sizes by a combination of screening and sedimentation methods. The histological purity of the fractions is established by light and electron microscopy. It is also shown that the random nature of the ultrasonic disruption process results in the production of components of a continuous range of sizes from cortical cells down to needle· like components of size approaching that of microfibrils.

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Density Gradient Techniques.

Cited by 151 publications

References 33 publications

Steady state model and experiment for an oscillating grid turbulent two-layer stratified flow

Steady state model and experiment for an oscillating grid turbulent two-layer stratified flow

Refractive-index and density matching in concentrated particle suspensions: a review

The Chemical Composition of Wool

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