Granulometric analyses

Table 2 Granulometric analyses of the emulsions made of the different P-cyclodextrin-grafted silicones...

The same type of observations could be made from granulometric analyses carried out with the help of small angle laser light scattering. This technique allows the observation of both the sub-miaonic PMFIS-CD particles and the much larger griseofulvin... 

Fig. 7 Granulometric analyses of griseofulvin loaded particles of PMHS-CD(40) drawn from small angle light scattering measurements performed at different loading stoichiometries (griseofulvin P-cyclodextrin). O 0 1 (blank particles) B 2 1 5 1 pure griseofulvin...

The relative representation of particular fractions in the fine soil is used for classifying soils and earths based on results of their granulometric analyses. Particular species of soils or earths are classified according to the percentage abundance of one or more grain-size categories. 

The granulometric analyses have been performed by using a Sympatec diffractometer that operates in a range between 0.90 and 175 pm. This technique is based on the incidence of a monochromatic laser beam through a non-reactive liquid carrying a suspension of the sample to be analyzed. To provoke the total dispersion of the samples in the non-reactive liquid, isopropylic alcohol was used to remove the electronic and Van der Waals forces between the particles. 

The experiments were performed in a lab-scale plant with sample sizes of about 200 - 400 g powder and in a small pilot plant with sample sizes of 1 - 3 kg powder. Depending on the nozzles (orifices 0,4 / 0,5 /1,0 mm, spraying angles 30° and 90°), the kind of PEG (MW 1500/4000/8000/35000) and on pressure (100-250 bar) and temperature (45 - 70 °C) the spraying times reached from about 45 s to 180 s. The obtained particles were characterised by Scanning Electron Microscopy, Differential Scanning Calorimetry and by granulometric analysis. The results can be summarised as follows ... 

Separation analysis at the outlet of the detector must respect three major conditions. The first is the cell integrity (i.e., the diagnosis of the particle). This can be operated on line, by means of classical photometric devices operated in the light-scattering mode (opacimetry) at 254 nm. Off-line methods, after fraction collection, are possible and recommended, by microscopy and granulometric analysis (Coulter counting). The second objective is to analyze cell viability. Off-line methods after fraction collection are equally possible. The blue trypan exclusion test, motility measurements, or specific enzymatic activities (esterase) can be performed on an aliquot of the collected fraction. 

Granulometric analysis of fractions 1, 2, 3 (Fig. 6) clearly shows that particles are mainly supracolloids, between 1 to 100 xm, with a mode value close to 30 xm. The fraction 4 (at the bottom of the Imhoff cone) presents the widest range size with particle larger than 100 im, and a multi-modal distribution. After 1 h of settling, the separation of settleable matter is achieved, as fractions 1 to 3 do not contain particles of size above 100 xm, even if, in the first fraction, some millimetric floating particles are present. One can note that no colloidal population is detected by laser granulometry. 

The solid phase of soil contains particles of different sizes, and it has different textures. The granulometric analysis of the soil presents data about the relative (percentage) abundance of particles of a certain size and it serves as a basis for soil categorization. 

Lux et al. [7] argued that the results of the granulometric analysis rather reflect the distance between fibers than the pore size distribution of a certain shaped pore. The determined pore size distributions can be significantly influenced by the choice of the shape of the structuring element. For example, if spherical structuring element is used the number of adjacent voxels increases and affects the frequency of pores detected by this structuring element. 

The data evaluation time (calculation time) is one of the most crucial and limiting factors for this kind of analysis using MATLAB. For very small sub-volumes the granulometric analysis can be achieved within a few minutes sub-volumes of approximately 2 x 2 x 9.6 mm, as used in the work here and corresponding to 4.5 X 10 voxels, however, require several hours of calculation time using a standard consumer computer. 

Mastersizer 2000 granulometric analysis of ash, char and bed particles col-a filter candle placed in the freeboard of a laboratory-scale fluidized bed gasifier... 

DETERMINING THE TYPE OF SOIL. Every soil cousists of mineral particles of varying sizes. The ratio of the particle sizes present in a soil largely determines the properties of the soil. The granulometric composition (texture) of a soil can he precisely determined hy laboratory tests (sieve and sedimentation analysis). Large particles are determined hy sieving and finer ones by sedimentation. The soil type is apparent from the ratio of the individual granulometric fractions. 

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