Porosity measurements

F.A. Reed, T. Batzinger, R.W. Reed, and S. Jonsson. Porosity measurement of composites using attenuation methods. Review of Progress in Quantitative Nondestructive Evaluation, 12, 1993. 

For the neutron porosity measurement, fast neutrons are emitted from a 7.5-curie (Ci) americium-beryllium (Am-Be) source. The quantities of hydrogen in the formation, in the form of water or oil-filled porosity as well as crystallization water in the rock if any, primarily control the rate at which the neutrons slow down to epithermal and thermal energies. Neutrons are detected in near- and far-spacing detectors, located laterally above the source. Ratio processing is used for borehole compensation. 

The caliper is used to correct the density and neutron porosity measurements for borehole effects and also can be used as a borehole stability indicator. Figure 4-289 shows an example of comparison between the MWD ultrasonic caliper and the four-arm wireline caliper run five days later. 

Due to the small dimensions of the micrograin [<1 X Iff-2 cm according to the porosity measurements (55)], diffusional restrictions at this level may occur only at rather high (tens of kilograms per gram of catalyst per hour) polymerization rates. 

Figure 3. Porosity measurements on a microscopic scale for a small (2 cm X 2 cm X 30 urn) thin section of sandstone impregnated with fluorophor-doped polymer. Average porosity - 16.3% range of porosities - 1.8-42%.

In the course of the investigation detailed porosity measurements helped to improve the description of the influence of the wall on the porosity. 

N2-BET analysis and porosity measurements were done on a Micrometries ASAP 2000 apparatus at liquid nitrogen temperature. Temperature-programmed desorption of ammonia (NH3-TPD) and temperature-programmed reduction by H2 (H2-TPR) were performed with a Micromeritics AutoChem 2910 apparatus. 

At temperatures below Zone II, equilibrium burning (as illustrated in Fig. 10) obviously is not obtained. It is found, however, that after some bumoff (usually less than 5 %) the reaction rate is essentially constant over a wide burnoff range. A typical reactivity plot is shown in Fig. 12. If it is assumed that the porosity measured at the close of the run is derived from uniform burning over time Af, then... 

Certain of the physical data (Table III) appear to be less than satisfactory. In general, agreement between the two types of porosity measurements is not good and the values for DC3-3600, UE15-7 and UE15-7a appear excessively large. The densities of the quartz monzonite appear unusually low, i.e., values in the range 2.6 to 2.7 were expected... 

Fic,. 21. Hydroxyl population on silica, y alumina, and aluminum phosphate having similar porosity. (Measured by reaction with methylmagnesium iodide.)... 

Coal density is a useful parameter not only for deducing the spatial structure of coal molecules, but the relationship between the density and porosity suggests that emphasis must be given to density and its determination. Porosity measurement, in turn, provides useful information on the technical behavior of coal toward its end use. Particle density is required for calculating the porosity of individual coal particles. 

The method of product porosity measurement depended on the size of product particles. The porosity of granules for the size fraction dg < 4 mm was determined on the basis of bulk density measurement. The porosity of granules from a given size fraction was calculated from the formula... 

Porosity Measurements via Determination of the Gibbs-Thomson Relation... 

Similarly, we polymerized the same mixture used for the preparation of capillary columns in glass vials and used the product for mercury intrusion porosimetry. Since we found that a strong correlation exists between the "dry" porous properties of the monoliths and their chromatographic performance, even dry porosity measurements may be used to tailor column performance. 

Sample Sample identity Theoretical NaCl particle distribution (pm) Pore size distribution (pm) Theoretical Porosity (%) Measured Porosity (%)... 

Computer Controlled Vacuum Microbalance Techniques Of Surface Area And Porosity Measurements. K. A. Thompson and E. L. Fuller, Langmuir 3 (5) (1987)699-703... 

Anderson, N.R. Banker, G.S. Peck, G.E. Quantitative evaluation of pharmaceutical effervescent systems II stability monitoring by reactivity and porosity measurements. J. Pharm. Sci. 1982, 71, 7-13. 

In the literature, the reported use of zeta potential measurement for non-aqueous suspensions is relatively infrequent because non-aqueous suspensions only represent a small percentage of all medicated suspensions. Su and others evaluated the flocculation-deflocculation behavior of cefazolin sodium in non-aqueous media and the effect of surfactants as measured by zeta potential along with sedimentation and porosity measurements. A significant difference in zeta potential was observed when the particles were dispersed in peanut oil and ethyl oleate. The addition of lecithin reduced the zeta potential of cefazolin sodium, resulting in a deflocculated state accompanied by a decrease in sedimentation volume. The effect of surfactant... 

In the case of the porosity measurements, in addition to the same cellulose samples, samples of oak and white pine were also examined. These samples of wood were ordinary commercial lumber samples (the same pine having been previously used in fire experiments at the Center for Fire Research of the National Institute for Standards and Technology). The pine had an initial dry density of 0.377 g/cc, and the oak 0.734 g/cc. Both of these wood samples were pyrolyzed for two hours at 1273 K, in helium, in order to prepare the chars for testing. The char yields were in the neighborhood of 28% by mass of the starting oak and 26% by mass of the starting pine. 

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