Sample particle size

The catalyst samples were screened to give a 200- by 325-mesh particle size sample. This was done to remove fines and coarse particles and hence assure good fluidization characteristics with minimal entrainment of fines. As a result, the majority of the particles in the sample has a particle size between 44 and 53 microns. Dry ice was used to eliminate plugging of the screen due to static electricity. 

The sampling operation involves collection of an aerosol sample that is representative of the particle size distribution and concentration of the sampled atmosphere. The efficiency of particle transport and collection operations are dependent on the particle size, sampling velocity, the geometry of the sampling apparatus and the properties of the collection medium. In the present work, a 37 mm diameter membrane filter (0.3 ym pore size) is the primary collection medium under evaluation. The filter is housed in a standard filter cassette and effects of filter-holder inlet geometry are also being investigated. 

Effect of Particle Size on the Rate of Desorption of Hydrogen from St. Nicholas Anthracite at Constant Temperature. If the rate of evolution of H2 is controlled by the rate of desorption of H2 from the surface of anthracite and not by the rate of transport of the H2 from the pore system, the rate of evolution should be independent of particle size. However, this was not found to be the case. For St. Nicholas anthracite, the initial rate of H2 release was determined on a 12 X 16 mesh fraction over the temperature range 700°-750°C. and compared with the previous results for initial rate of release on a 150 X 200 mesh fraction. Results are summarized in Table II. The results show clearly that the rate of H2 evolution at all temperatures studied was more rapid from the larger particle sized sample. The activation energy for H2 evolution at 9 — 1 from the 12 X 16 mesh fraction is calculated as 89 kcal./ mole, compared with 96 kcal./mole for the 150 X 200 mesh fraction over the same temperature interval. 

Residual moisture moisture remaining in the sample after air drying assayed by determining the mass lost from drying the sample at 104 to 110°C (219 to 230°F) at specified conditions of residence time, atmosphere, particle size, sample mass, and equipment configuration (ASTM D-3173 ASTM D-3302). 

Type Thickness Particle Size Sample Size... 

For the Si02-H20 system the possibility of impurity contents being the determining factor has been eliminated (21). It was also shown (II, 22) that the Avariation with specific area can be generated from an initially coarse quartz powder by extensive grinding and subsequent fractionation into a series of particle size samples. The various AH0 s obtained from AH/s (see Equation 1) for Si02 samples outgassed at 160° C. and 10 6 mm. of Hg are listed in Table I. 

Bell, R. Dennis, A. Hendriksen, B. North, N. Sherwood, J. Position paper on particle sizing sample preparation, method validation and data presentation. Pharm. Technol. Eur. 1999, 11 (11), 36 2. 

To explain the hydrophilic role, the protocol of the dry adsortied emulsion preparation was modified as follows. Instead of preparing the primary emulsion, the hydrophilic silica (Tixosil 3S) and the aqueou.s phase (Table I) were mixed in a beaker at room temperature. The whole aqueous solution was absorbed by the hydrophilic silica and this wet powder was added to the oil phase at 60 0. After this lirst step, the hydrophobic silica was mixed to the creamy liquid, following the normal procedure. Table 3 (bottom) presents the kinetic parameters obtained with the dry adsorbed emulsion prepared with the alternative procedure (form I ). Figure 4 (curve 1 ) presents the release of sodium salicylate vs. lime for the medium particle size sample (800-1250 pm) at pH 1.2 compared with the results obtained with other dry adsorbed emulsions. The drug release was faster and the amounts of drug released very rapidly, and Lu were higher. 

In Kubelka-Munk equation it is assumed that s is indep>endent of wavelength and the sample is weakly absorbing. The former condition is achieved by proper sample preparation and the latter by dilution of strong absorbing samples with non-absorbing substrate powder (such as KBr or KCl). Therefore, to obtain reproducible results, particle size, sample packing and dilution should be carefully controlled, especially for quantitative analysis. 

Figure 3.4 TG curve fur dehydration of whewcllite with different particle sizes (sample mass 6 mg). Heating rate, 2 C min . The arrow in the figure shows 0.2 mg. I, Powder 11, Single crystal...

The pilot ICDACs were obtained by blending the activated carbon samples produced during two of the pilot production tests and ground to two particle size ranges (5 and 8pm). The finer particle size sample, AC-F, had a slightly greater ash content (24.7 wt.%) than did the coarser AC-C sample (18.8 wt.%). The surface areas of the pilot carbons (671 and 688 m /g) were comparable to the activated carbon produced from C2 coal in the bench FBR (FBR-39 series). 

Eventual variations in particle size, sample presentation, and process conditions must be represented within the test sample population... 

Modest reproducibility (particle size, sample packing) and quantitation... 

The large particle size sample is the starting crude pigment with the median diameter near 750 nm. The smaller particle size sample is the finished pigment with the median particle diameter near 130 nm. 

Konkol LM, Cross RE, Harding IH et al (2003a) Contaminants and levels of occurrence in washed and shredded poly(ethylene terephthalate) from curbside collection II validation of extraction procedures, particle size sampling and crystallinity. Food Addit Contam 20(10) 972-984... 

Casein and whey were obtained from Sigma (St Louis, MO) and were used as is. Cheese flavored crackers, chocolate cookies, and freeze-dried coffee were commercially obtained products. Samples were ground if necessary and sieved to obtain a particle size range between 50 and 70 mesh (CE Tylor Inc., Mentor, OH). Sample particle size was important since the surface area, amount, and rate of flavor release change with particle size. Samples were protected from moisture changes and stored in an airtight container until used. Samples were used as is and not dried initial moisture and sample RH measurements were made. 

With good samples, the transmission camera is capable of 0.3 % using an internal standard. Selected-area diffraction gives about 0.5 %, and reflection diffraction about 1 %. Electron diffraction patterns are sensitive to surface defects, particle size, sample position and orientation, and refraction effects, so that most materials are unsuited to precision measurements. Normally, electron diffraction is a poor second to X-ray diffraction as far as accuracy is concerned. 

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