Particle recovery curve

FIGURE 7-27 Typical particle recovery curve for the underflow from a hydrocyclone. 

Figure 52 also shows that the actual recovery curve does not decrease below a certain level. This indicates that a certain amount of material is always recovered to the underflow and bypasses classification. If a comparison is made between the minimum recovery level of solids to the liquid that is recovered, they are found to be equal. Therefore it is assumed that a percent of all size fractions reports directly to the underflow as bypassed solids in equal proportion to the liquid split. Then each size fraction of the actual recovery curve is adjusted by an amount equal to the liquid recovery to produce the "corrected recovery" curve shown in Figure 52. As the Djoc point changes from one application to another, the recovery curves shift, along the horizontal axis. In order to determine a single graph which represents the corrected recovery curve, the particle size of each size fraction is divided by the Dj value and a "reduced recovery" curve can be plotted, as shown in Figure 53. Studies reported by Arterburn have shown that this curve remains constant over a wide range of cyclone diameters and operating conditions when applied to a slurry...

Particle recovery for the experiment in figure 3A and 3B can be estimated from the integrated area under the curve for the SdFFF analysis of the tissue sample and the reference sample [19]. Particle recovery in the enzyme digestion processing was 30% for the 250 nm particles and 22% for the 70 nm particles. These recoveries are representative of one set of experimental data. 

The 1000 A column did not show any resolution between 312 nm and 57 nm particle sizes. Shown in Fig.2 are the calibration curves for the 2000 A and 3000 A columns and for their combination. The 57 nm particle standard appears to have been erroneously characterized by the supplier. This was subsequently confirmed by electron microscopy. The 2000 X column exhibited a sharp upturn in its calibration curve close to the exclusion limit. It is to be noted that while data points corresponding to 312 and 275 nm diameter particles appear on individual column calibration curves, they are not indicated for the calibration curve of the combination. This is because these larger diameter particles were completely retained in the packed colimms, generating no detector response. The percentage recovery for these particles from individual columns was considerably less than 100 resulting in their complete retention when the columns were combined in series. 

Comparative evaluation of anti-human thyroid stimulating hormone (hTSH) antibody, bound to the fifth-generation ammonia core (N5) or the fifth-generation ethylenediamine core (E5) dendrimer (1), did not show any differences in either the effective protein concentrations or the shape of the dose-dependent response curves (calibration curves) as determined from the recovery of standard controls. All the other experiments described here were thus carried out with the fifth-generation (i.e. dia. = 70 A) particles of ethylenediamine core (E5) de-ndrimers. The later particles were selected for their ability to be produced reproducibly on a large scale. 

Definitions. The performance of a hydrocyclone is generally characterised by means of a grade efficiency or Tromp-curve which is the fractional mass recovery expressed as a function of particle size. 

Figure 2. (Top) Detail of the MULVFS pump unit and filter-holder assembly. The filter holder consists of three stages. The upper two plates are baffles necessary to prevent particles from being redistributed on the filters during recovery. The next plate supports the 53-gm mesh Nitex prefilter, and the bottom plate supports the pair of 1-pm micro quartz-fiber filters and seals to the pump intake. (Bottom) Pressure vs. flow rate curves for the MULVFS and LVFS pump units. Horizontal bars indicate operating ranges of the two systems during filtration.

On the basis of the polymerization alone, it is difficult to specify definite dryer selection rules since typically polymer properties differ over a wide range. The choice of dryer is also limited by the physical properties of the polymers, e.g., polymer-handling characteristics, individual or closely related drying curves, properties of the emitted volatiles, limitations on temperature, and particle size and distribution requirements. Other factors include equipment space limitations, production rates, pollution control requirements, solvent recovery, thermal sensitivity, and product quality specifications. 

Calibration curves are obtained by measuring the residence time of known-size standards (such as the monodisperse polystyrene latexes manufactured by Dow) at a given eluent ionic strength. Typically, 6-10 particle sizes in the submicron range are needed to produce an accurate curve. In addition, comparison of chromatogram peak areas for samples run through the column and bypass lines allow determination of the upper size limit for 100% recovery... 

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