Coulter Counter size analysis

The feed dust in these tests was supplied by the Cataphote Division of Ferro Corporation as Class IV-A uncoated Unispheres of soda-lime glass in a nominal 13-44 pm diameter. A Coulter counter size distribution analysis indicated that the size ranged only between 20 and 51 pm, with 14% greater than 40 pm and 3% smaller than 25 pm. These particle sizes are in the same range as those of the tests with particles prepared from pilot plant deposits. The burner... 

Various techniques and equipment are available for the measurement of particle size, shape, and volume. These include for microscopy, sieve analysis, sedimentation methods, photon correlation spectroscopy, and the Coulter counter or other electrical sensing devices. The specific surface area of original drug powders can also be assessed using gas adsorption or gas permeability techniques. It should be noted that most particle size measurements are not truly direct. Because the type of equipment used yields different equivalent spherical diameter, which are based on totally different principles, the particle size obtained from one method may or may not be compared with those obtained from other methods. 

While more commonly used to count or otherwise characterize cells for medical applications, Coulter Counters and flow cytometry technique can also be applied to the analysis of pollen grains in allelopathic studies. They are quite useful in determining the size and number of pollen grains. The technique is often used for assessing the production and size of pollen from the originating individual rather than how much was transferred to heterospecific stigma, as would be needed in a basic assessment of potential allelopathic interactions. 

Computer programs accounted for the presence of oil drops below- the detection limit of the Coulter Counter. The data processing procedure, which assumed that the oil-drop size distribution was lognormal, yielded accurate estimates of the true mean and standard deviation describing the emulsion drop size distribution. The data-analysis procedure did not affect the actual measured drop populations which were used in the kinetic studies. The computer programs are described in detail by Bycscda.8... 

Particle size Laser diffraction Coulter counter Photon correlation spectroscopy Microscopy Ro-Tap sieve analysis... 

Image analysis provide information based on the number of cells examined the question of the volume is therefore often raised, as some other sizing systems (Coulter counter, laser diffraction granulometers) provide volume-based results. It is important to note that, because an image is essentially a plane, volume estimation will require some assumption on the 3D-shape. Bacteria are often considered as cylinders with hemispherical ends at each side. Based on these simple geometrical assumptions their volume can be computed [94,95] ... 

The second method for obtaining the rate constant of flocculation is by direct particle counting as a function of time. For this purpose, optical microscopy or image analysis may be used, provided that the particle size is within the resolution hmit of the microscope. Alternatively, the particle number may be determined using electronic devices such as the Coulter counter or flow ultramicroscopy. 

Washington (1992) has discussed the concepts and techniques of particle size analysis and its role in pharmaceutical sciences and other industries. There are many different methods available for particle size analysis. The techniques most readily available include sieving, optical microscopy in conjunction with image analysis, electron microscopy, the Coulter Counter and laser diffractometers. Size characterization is simple for spherical particles, but not for irregular particles where the assigned size will depend on the method of characterization used. Table 6.2 lists particle size measurement methods commonly used and the corresponding approximate useful size range (Mullin 1993). 

C. Washington and T. Sizer, Stability of TPN mixtures compounded from Lipofundin S and Aminoplex amino-acid solutions Comparison of laser diffraction and Coulter counter droplet size analysis, Int. J. Pharm. 83, 227-231 (1992). 

In addition to SEM, size analysis of the ghost cells was performed with a Coulter counter, and as shown in Figure 2, the size distribution is similar to that of the washed red cell preparation. 

Figure 3. Pints of mean particle size versus standard deviation of two prepared mixtures of standards analyzed by selected automated electronic particle size analysers (from Syvitski et al 1991a). The expected value is shown with a black box. S SediGraph C. Coulter Counter M Malvern laser panicle. sizer G Galai CIS-1, L Lumosed photosedimentometer lA Image analysis (Syvitski et al.. 1991a).

McCave, I. N. J. Jarvis, 1973. Use of the model T Coulter Counter in size analysis of fine to coarse sand. Sedimentology 20 305-315. 

Emulsion stability can be assessed by a great num ber of techniques which are generally based on the analysis of the droplet size distribution. Most of these techniques are easily applicable to diluted oil-in-water (0/W) emulsions (e.g. light scattering. Coulter counter, and microscopy), but they are unfortunately not adaptable to opaque W/0 emulsions. Even optical microscopy, which is considered as a universal technique in the field of emulsions, is very... 

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