Particle size, measurement manual

Particle size measurements are usually made from micrographs. The method is extremely tedious if it is done manually. Automatic image analysis of micrographs or an electronic display can reduce the amount of work considerably. Normally a large number of particles (a few hundred) need to be measured. As would be apparent, microscopy produces a particle size distribution based on the numbCT of particles within an appropriate size range. 

The available data from emulsion polymerization systems have been obtained almost exclusively through manual, off-line analysis of monomer conversion, emulsifier concentration, particle size, molecular weight, etc. For batch systems this results in a large expenditure of time in order to sample with sufficient frequency to accurately observe the system kinetics. In continuous systems a large number of samples are required to observe interesting system dynamics such as multiple steady states or limit cycles. In addition, feedback control of any process variable other than temperature or pressure is impossible without specialized on-line sensors. This note describes the initial stages of development of two such sensors, (one for the monitoring of reactor conversion and the other for the continuous measurement of surface tension), and their implementation as part of a computer data acquisition system for the emulsion polymerization of methyl methacrylate. 

To account for scale-up effects, especially using dissimilar equipment, formulators have employed a variety of approaches. Typically, trial and error adjustments, empirical correlations between known machines, and several geometric rules of thumb have been devised. Usually, trial and error approaches will alter the amount of granulation liquid used, the post-liquid addition mixing time kneading, or the liquid addition rate to arrive at an acceptable formulation upon scale-up. Although particle size distribution and bulk/tap density measurements may be used to establish equivalence in these methods, often visual judgments are made by experienced operators on the floor with a feel for proper appearance and manual consistency. 

Although particulate methods are potentially more informative than bulk methods because of the extra information obtained on particle size, their application in coal mineralogy has been relatively limited The main reason for this has been the lack of automation, as such microscopic measurements are time-consuming and tedious if sufficient data have to be generated manually Recently, however, the application of microcomputers and image-analysis systems to microscopy has progressed to the extent that most of the operation, data collection, and analysis can now be done automatically A number of reports of such automated microscope techniques used in coal research have appeared recently in the literature (3-8) ... 

Use any instrumental technique for measurement of particle size distribution, to determine the particle size distribution of the medium-sized dolomite. Follow up the procedure described in the manual of the instrument. 

The distribution of size of the particles may also be analyzed with the use of vibratory sieves, with the sieve patterns determined according to the size range of the sample, which will go through progressively smaller meshes (Albertini et al, 2009). Ribeiro et al. (2012) suspended the samples in glycerol and manually measured the diameter of 500 particles in each sample. Two measurements were carried out (horizontal and vertical), and the mean was considered. 

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