Bulk volume

Several densities and void fractions are commonly used. For adsorbents, usually the bulk density p, the weight of clean material per unit bulk volume as packed in a column, is reported. The dry particle density Pp is related to the (external) void fraction of packing by... 

Material and Ball Charges The load of a grinding medium can be expressed in terms of the percentage of the volume of the mill that it occupies i.e., a bulk volume of balls half filhng a mill is a 50 percent ball charge. The void space in a static bulk volume of balls is approximately 41 percent. Since the medium expands as the mill is rotated, the ac tual running volume is unknown. 

When Ha 1, all of the reaction occurs in the film and the amount of interfacial area is controlling, necessitating equipment that has a large interfacial area. When Ha 1, no reaction occurs in the film and the bulk volume controls. The Hatta criteria are often applied in the following form. 

We may begin by describing any porous medium as a solid matter containing many holes or pores, which collectively constitute an array of tortuous passages. Refer to Figure 1 for an example. The number of holes or pores is sufficiently great that a volume average is needed to estimate pertinent properties. Pores that occupy a definite fraction of the bulk volume constitute a complex network of voids. The maimer in which holes or pores are embedded, the extent of their interconnection, and their location, size and shape characterize the porous medium. 

Bulk density, soil - Mass of dry soil per unit bulk volume (combined volume of soil solids and pore space). 

Figures 13.8 and 13.9 show the separation of polystyrene standards using a typical mixed-bed column and its calibration plot, respectively. The major advantages of using a large i.d. 10-mm column are low hack pressure and relatively short run times. As seen in Fig. 13.8,10 standards from toluene thru 8.4 X 10 MW can be resolved in a mere 21 min. Because of the large 10-mm i.d. columns, 1.5-ml/min flow rates give a linear velocity equivalent to that of only 0.9 ml/min using a 7.6-mm i.d. column. Also, the gel volume contained in one 10 mm i.d. X 500 mm column is 39.3 ml, whereas a 7.6 mm i.d. X 300 mm column contains only 13.6 ml of gel volume. This bulk volume factor, combined with the large pore volumes of gels, obtains essentially the same resolution as that obtained on three standard 7.6 X 300-mm columns in series, but in about one-half the usual time required using the smaller columns.

Porosity is a measure of the void space within a rock, which is expressed as a fraction (or percentage) of the bulk volume of that rock [31]. 

Apparent Bulk Density—ABD. The density of the catalyst at which it is shipped either in bulk volume or bags. It is density of the catalyst at minimum fluidization velocity. 

Porosity (ej>) determination with NMR is a direct measurement as the response is from the fluid(s) in the pore space of the rock. The initial amplitude (before relaxation) of the NMR response of the fluid(s) saturated rock (corrected for hydrogen index) is compared with the amplitude of the response of bulk water having the same volume as the bulk volume of the rock sample. The 2 MHz NMR... 

If the NMR response is capable of estimating the pore size distribution, then it also has the potential to estimate the fraction of the pore space that is capable of being occupied by the hydrocarbon and the remaining fraction that will only be occupied by water. The Free Fluid Index (FFI) is an estimate of the amount of potential hydrocarbons in the rock when saturated to a given capillary pressure. It is expressed as a fraction of the rock bulk volume. The Bulk Volume Irreducible (BVI) is the fraction of the rock bulk volume that will be occupied by water at the same capillary pressure. The fraction of the rock pore volume that will only be occupied by water is called the irreducible water saturation (Siwr = BVI/cj>). The amount of water that is irreducible is a function of the driving force to displace water, i.e., the capillary pressure. Usually the specified driving force is an air-water capillary pressure of 0.69 MPa (100 psi). 

G. R. Coats, D. Marschall, D. Mardon, J. Galford 1997, A New Characterization of Bulk-Volume Irreducible Using Magnetic Resonance, paper QQ presented at the SPWLA 38 Annual Logging Symposium, Houston, TX, June 15-18, 1997. 

FIGURE 51 Drying clay. The illustration shows a schematic, highly magnified cross section of a mass of wet clay at three different levels of water contents. Initially, all the space around the clay particles is filled with water (a). As the wet mass dries up, water is lost from between the particles, which gradually come nearer to each other (b), and the clay mass shrinks in size. When all the water has evaporated, the particles are in contact with each other and the mass cannot shrink any further (c). From this point onward the bulk volume of the clay mass does not change. 

The most common method for measuring bulk density is to pour the powder into a tared graduated cylinder and measure the bulk volume (Vb) and mass of the material. Other methods, however, have been employed to ensure reproducibility, and a standard procedure has been reported [62,64]. For this testing, a sample of 50 g is passed through a U.S. Standard No. 20 sieve and is poured into a 100-ml graduated cylinder. The cylinder is then dropped from a height of 1 inch onto a hard surface three times at 2-second intervals. The volume of the powder is then read and used to calculate the bulk density. This three-tap method was found to give consistent results between laboratories. 

Bulkiness, or specific bulk volume, is defined as the reciprocal of the bulk density [5,62]. It is often measured for the packaging of powders and, as expected, is affected by particle size. Bulkiness will increase with a decrease in overall particle size. A sample exhibiting a wide particle size distribution, however, will result in a lower bulkiness because the small particles will occupy the void spaces formed by the larger particles. 

Probability (e) of Free Radical Escaping from the Cage into Bulk Volume in the Decomposition of Initiators in Polymer Matrix... 

Figure 25. The free energy of interaction between two DMPC membranes at various degrees of surface tension as indicated. We note that the indicated surface tension is the tension at large membrane-membrane spacing. The salt bulk volume fraction was cps — 0.002. Redrawn from [85] by permission of the American Chemical Society...

Preferred fluid migration pathways are influenced by porosity and permeability, sedimentary sequences, facies architecture, and fractures. Porosity is a measure of pore space per unit volume of rock or sediment and can be divided into two types absolute porosity and effective porosity. Absolute porosity (n) is the total void space per unit volume and is defined as the percentage of the bulk volume that is not solid material. The equation for basic porosity is listed below ... 

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