Particle size determination scanning electron microscop

Nitrogen adsorption isotherms were measured with a sorbtometer Micromeretics Asap 2010 after water desorption at 130°C. The distribution of pore radius was obtained from the adsorption isotherms by the density functional theory. Electron microscopy study was carried out with a scanning electron microscope (SEM) HitachiS800, to image the texture of the fibers and with a transmission electron microscope (TEM) JEOL 2010 to detect and measure metal particle size. The distribution of particles inside the carbon fibers was determined from TEM views taken through ultramicrotome sections across the carbon fiber. 

Particle size distribution was measured by a Particle Size Analyser (Malvern 2600C). For bulk chemical compositions samples were digested in diluted HNO3 solution using a CEM microwave digestion system. Dissolved samples were analysed by ICP-AES technique (Labtest PSX7521). Phase conditions were determined by X-ray diffraction analysis (XRD, Philips PW 1710). Scanning electron microscopic... 

Catalyst Characterization. Particle size distributions of oven dried products were determined with a Microtrac Particle Size Analyzer. PH, PM, and PS are the diameters corresponding to the 90th, 50th, and 10th percentiles, respectively, on the distribution curve. Particle microstructures were obtained with an ISI-SX-40 scanning electron microscope. 

Analysis of single particles by X-ray fluorescence using either a scanning electron microscope (SEM) or an electron microprobe can identify differences in the matrix composition between individual particles. The total concentration of the element can be determined as a function of particle size. Other physical fractionation and preconcentration methods include density and magnetic separations. 

The specific surface area of the activated catalyst was found to increase with alumina content up to about 20 m /g at around 2% AI2O3 and then to remain constant (10), demonstrating the role of this additive as structural promoter that (together with other nonreducible phases such as hercynite and calcium ferrite) prevents sintering of the metallic iron particles into low surface area material. These values are compatible with the mean particle sizes of around 30 nm, as determined by mercury porosimetry and seen directly in the scanning electron microscope (Fig. 2) (11). This agreement further shows that the texture of the catalyst permits the N2 molecules of the BET analysis to reach essentially the whole internal surface. 

A recent paper by Borgwardt and Harvey [79] on the kinetics of this reaction is interesting, not only as a report of an extensive experimental investigation, but also because the conclusions presented are in conformity with the ideas developed in this book. Borgwardt and Harvey characterized eleven diverse types of carbonate rock by a polarizing microscope and scanning electron microscope. The rocks were then calcined, crushed, screened, and subjected to further examination under these microscopes and by mercury penetration porosimeter and by a BET apparatus. An increase in porosity was observed after calcination moreover, there was considerable variation in the mean pore diameter and in the pore volume from rock to rock. The rates of reaction of each of three particle sizes of each calcine with a gas containing 3000 ppm of SO2 at 980°C were then measured and microprobe scans of the reacted calcines were made to determine the location of the absorbed sulfur within the particle. 

Microscopic examination permits measurement of the projected area of the particle and also enables an assessment to be made of its two-dimensional shape. In general, the third dimension cannot be determined except when using special stereomicroscopes. The apparent size of particle is compared with that of circles engraved on a graticule in the eyepiece as shown in Figure 1.3. Automatic methods of scanning have been developed. By using the electron microscope 7, the lower limit of size can be reduced to about 0.001 pan. 

Optical microscopy and scanning electron microscopy (SEM) were used to evaluate the drug incorporation and surface shape of the microspheres prepared under the various conditions. Particle size was determined using a Tiyoda microscope. Samples of microspheres (180-200) were dispersed on a slide and their diameter was then sized using suitable objectives. 

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