Surface diameter

SSD = selective surface diameter determined by ASTM D1366. 

Rubber media appear as porous, flexible rubber sheets and microporous hard rubber sheets. Commercial rubber media have 1100-6400 holes/in. with pore diameters of 0.012-0.004 in. They are manufactured out of soft rubber, hard rubber, flexible hard rubber and soft neoprene. The medium is prepared on a master form, consisting of a heavy fabric belt, surfaced on one side with a layer of rubber filled with small round pits uniformly spaced. These pits are 0.020 in. deep, and the number per unit area and their surface diameter determine the porosity of the sheet. A thin layer of latex is fed to the moving belt by a spreader bar so that... 

The minimum case is when rhe diameter of vena contracta of the plume is about 80% of the upper surface diameter and is located approximately one-third of a diameter above the source. I he spreading angle of rhe plume is set ro 25". For low-temperature sources, Skistad - recommends the maximum case, whereas rhe minimum case best fits the measure ments for larger, high-temperature sources. 

The size of a spherical particle is readily expressed in terms of its diameter. With asymmetrical particles, an equivalent spherical diameter is used to relate the size of the particle to the diameter of a perfect sphere having the same surface area (surface diameter, ds), the same volume (volume diameter, dv), or the same observed area in its most stable plane (projected diameter, dp) [46], The size may also be expressed using the Stokes diameter, dst, which describes an equivalent sphere undergoing sedimentation at the same rate as the sample particle. Obviously, the type of diameter reflects the method and equipment employed in determining the particle size. Since any collection of particles is usually polydisperse (as opposed to a monodisperse sample in which particles are fairly uniform in size), it is necessary to know not only the mean size of the particles, but also the particle size distribution. 

Curve Investigator(s) Circum location Heating surface Diameter... 

As we just suggested, particle size and shape are important physical properties influencing powder flow and compaction. Particle size is a simple concept and yet a difficult one to quantitate. Feret s diameter, Martin s diameter, projected area diameter, specific surface diameter, Stokes diameter, and volume diameter are but several of the measurements that have been used to quantify particle size using a variety of methods. 

Bathymetry shows that the shape of Pit Lake resembles of a funnel with the an upper surface diameter of 110 m and the diameter of the neck of 50 m. The depth from the surface of the lake to the funnel neck is approximately 20 m (the approximate position of the former crown pillar) and the total depth of the lake is 130 m. Lake outflow is controlled by a culvert at elevation 236.4 m above sea level. Field investigation indicates that the lake is fed by surface runoff and seepage of groundwater through the overburden and fractured walls of the pit (Fig. 1). 

The mean surface diameter is defined as the size of particle d s which is such that if all the particles are of this size, the total surface will be the same as in the mixture. 

Coppeta et al. [10] made slurry film measurements during using laser-induced fluorescence. By addition of a fluorescent dye to the polishing slurry film thickness was experimentally from the fluorescence intensity of the lubrication film as measured through a transparent substrate. Film thickness measurements were in good agreement with those of Levert et al. [7,8]. This technique can also be used to study slurry transport across the wafer surface, diameter variation in lubrication film thickness, and slurry mixing effects [11]. 

The electron beam used as a probe in AES can be focused to analyze a very small area on the sample surface (diameter l-50p) 62 172). On the other hand, the spatial resolution that can presently be achieved with XPS is relatively poor since it is very difficult to focus the X-ray beam. Therefore, since AES and XPS techniques exhibit complementary strengths, they are often employed together to achieve an accurate determination of the locus of failure in adhesion systems. 

Granular beds may consist of mixtures of particles of several sizes. In flow problems, the mean surface diameter is the appropriate mean, given in terms of the weight fraction distribution, x by... 

Figure 1.2. Schematic illustration of multidimensions of a particle and its equivalent volume diameter, surface diameter, and sieve diameter.

Surface Diameter, Volume Diameter, and Sauter s Diameter The surface diameter, ds, volume diameter, d, and Sauter s diameter, d, are defined such that each of them reflects a three-dimensional geometric characteristic of an individual particle. A surface diameter is given as the diameter of a sphere having the same surface area as the particle, which is expressed by... 

The concept of the surface diameter may be mostly used in the field of adsorption and reaction engineering, where the equivalent surface exposure area is important. The determination of the surface area depends on the method of measurements for example, permeametry can give a much lower area than does gas adsorption. The latter often includes the contribution of pore surface area, which is accessible to the gas molecules. The determination of particle surface area by gas adsorption is given in 1.2.2.4. The fundamentals of gas adsorption are further covered in 1.4.1. 

It is noted that in the evaluation of the particle surface diameter and Sauter s diameter, as discussed in 1.2.1.3, only the external surface area of the particle is considered. 

A comparison of the procedure outlined for determining particle-size indicates that the diameters so obtained correspond with the de diameters of sedimentation procedures. Fairs attributes this correspondence to areal matching inherent in his technique. However, agreement with surface diameters determined by turbidimeter was not wholly satisfactory. 

Examination of the metal surface after removal of the corrosion product showed the extent of the pitting corrosion taking place. At higher magnification, the pits appeared quite deep ( 150 pm) with an external surface diameter of 50 pm (Figure 7.103). 

About 65 mL (860 g) of mercury was used, giving a pool with a surface diameter of ca. 6 cm. 

Most recently, Sano et al.121 derived a relation for the liquid-solid mass-transfer coefficient (or Sherwood number) based on Kolmogoroff s theory for isotropic turbulence. The Reynolds number based on this theory is defined in terms of , the rate of energy dissipation per unit mass of liquid, dp, the specific surface diameter, and vL, the kinematic viscosity of liquid. Thus, the modified Reynolds number Re was defined as Re = Edp/vl. The Sherwood number was correlated as... 

At a low Re3uiolds number, the drag diameter equals the surface diameter of convex particles. For this case, the Stokes diameter, defined as the free-fall diameter in the laminar flow region, is related to sphericity as follows ... 

Hawksley [17] showed that this was equivalent to stating that the drag diameter closely approximates the surface diameter. 

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