Strand flow

In the flat die process the melting strands flow into the flat die (Fig. 2.7) and spread across the flow direction into the breadth through the coathanger-shaped distribution duct of the die. The distribution duct leads to a slit-shaped canal across the whole width of the die, which the molten... 

The part of the entering solids mass flow that exceeds the critical load is completely attributed to the strands flowing directly into the catch of the cyclone section. The catch feeds the standpipe, where a certain amount of material is stored. It passes in the downward direction, until it is finally refed to the bed. 

Strand flow/two-phase flow. The D materials have been moved over long distanees in dilute-phase eonveying in some mining applieations. 

Figure 3 Phase diagram-type plot of reduced pressure analog versus the volume analog at constant reduced gas flow analog. Note similarities of strand flow to liquid phase, flow above strand flow to vapor phase, and homogeneous flow to gas phase.

Boundary B delineates the condition that prevents the possibility of strand flow over the stationary layer. The model established in this work to predict the boundary of low-velocity slug-flow is based on this understanding and the theory of mass, force and momentum balance. 

STABILITY ANALYSIS FOR STATE DIAGRAM OF STRAND FLOW... 

Note fr is equal to fw for an empty pipe and equal to fp for strand flow over stationary bed. Also, to separate the points having a negative slope on the (pfp)/(ps(l-8st))=constant curves from those having a positive slope, the limiting curve E is defined as the locus of points having a vertical slope on the (pfp)/(ps(l-Est))=constant curves ... 

Since the friction between the particles is higher than the fnction between the particles and the pipe wall, the thickness of the stationary layer must be high enough to prevent the stationary bed from moving, which is driven by the friction of the strand. For conveying with volumetric flow ratios (pfp)/(ps(l-8st))>0.019, which is limited by curve F, the thickness of the stationary layer will be constant as it is first formed at the inlet of the conveying pipeline and the layer will be extended. With strand conveying over the stationary layer, the fiiction force between the strand flow and stationary bed should be equal or less than the fnction force... 

From Eqn. (20), the thickness of the stationary layer is about 23% of the cross-sectional area flow channel for conveying with volumetric flow ratios (pfp)/(ps(l-Sst))>0.019. For any points on the limiting curve E, if there is any reduction in Fr, the points will enter the unstable region. Also, when the stationary bed is first formed, the stationary bed will reach the level where the lowest air velocity can be achieved. If the height of the stationary bed is lower than this level, particles will deposit to increase the level and if the height is higher, the particles on the stationary bed will be removed. Hence, for certain conveying conditions with volumetric flow ratios (pfp)/(ps(l-Est))<0.019, the level of the stationary bed can be different to maintain stable strand flow over the stationary bed. 

More recently, consideration of some of the tomographic work of Yan [6] in which strand flow has been shown to be particularly prevalent immediately downstream of a bend even at superficial air velocities well above the saltation value, and Molerus [7] in which strand flow is treated analytically, led the authors to suspect that an acceleration model based upon interfacial fiiction between a dense strand and a suspended flow, would be a more appropriate approach than the one mentioned above, particularly in that it would be substantially independent of the particle size effects which lead the previously described approach to be inappropriate. The model presented in this paper uses such a basis. 

Fig. 1. Southern blot analysis of DNA showing (a) step 1, an agarose gel containing separated restriction fragments of DNA, denoted by (—), which is immersed in NaOH to denature the double-stranded stmcture of DNA, and then transferred by capillary flow to a nitrocellulose filter. In step 2, the bound DNA is allowed to hybridize to a labeled nucleic acid probe, and the unbound probe is washed off In step 3, the filter is placed into contact with x-ray film resulting in (b) bands of exposure on the film which are detected after development and correspond to regions where the restriction fragment is...

FIGURE 4.30 Calibration curves for double-stranded DNA fragments on TSK-GEL SW and TSK-GEL PW columns. Column TSK-GEL SW or TSK-GEL PW, two 7.5 mm X 60 cm columns in series. Sample 22 fragments from Hoelll-cleaved pBR322 DNA and 6 fragments from EcoRI-cleaved pBR322 DNA. Elution 0.1 M NaCI in 0.1 M phosphate buffer, pH 7.0, plus I mM EDTA Flow rate 1.0 ml/min. Detection UV at 260 nm. 

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