Density compacted bulk

Bulk Density-Compacted (lbs/ft3) 45 Bulk Density-Uncompacted (lbs/ft3) 42 Hardness (Mohs) 7 Hegman 7.0-7.5 Median Diameter (Microns) 3.4 Oil Absorption (D-1483) 33 Typical Chemical Analysis, % ... 

The foUowing variables can affect a material s bulk density. (/) Moisture higher moisture content often makes a material mote compressible. (2) Particle size and shape often, the finer the bulk soHd, the mote compressible it is. The shape of the particles can affect how they fit together and thein tendency to break while being compacted. (3) Temperature some materials become mote compressible as thein temperature increases. This could be due, for example, to softening of the particles. (4) Particle elasticity elastic materials tend to deform significantly when they ate compressed. 

Coal piles are carefully constmcted to exclude air or to allow adequate ventilation. The latter requites larger sizes, graded as 4 cm+ without fines, for a voiding heating by ventilation. For exclusion of air, mixed sizes provide fines to fill the gaps between larger pieces. Pockets of large sizes must not be allowed because these provide access for air. The coal should be compacted to maximize the bulk density of the coal pile. 

Pai+icle size enlargement equipment can be classified into several groups, with advantages, disadvantages, and applications summarized in Table 20-36. Comparisons of bed-agitation intensity, compaction pressures, and product bulk density for selected agglomeration processes are highlighted above in Fig. 20-71. 

Crushing, selective particle size packing or hydraulic compaction can be used to reduce interparticle void space and increase the bulk density within the storage tank to approach the particle density of the carbon. Even with these extreme methods of packing, the fraction of the vessel which is micropore is never greater than 0.50 for any commercial carbon, considerably short of the 0.70 which is necessary for 170 V/V storage. 

In a recent study for the US Department of Energy [61], AGLARG have shown that suitable adsorbents for ANG can be produced from peach pit or coconut shell using KOH as the activating agent. These carbons, like all KOH produced carbons, were low in bulk density. Densities of greater than 0.6 g/ml were possible with compaction in small vessels (<50 ml) and deliveries of greater than 150 V/V methane could be obtained from 3.4 MPa at 298 K. 

Apparent Bulk Density (ABD) is the density of catalyst as measured, loosely compacted in a specified container. 

Typical results of the dry pelletizing process when a charge of carbon black and its plus 52-mesh seeds is tumbled in a drum (12) are shown in Figs. 31 and 32. Initially, the seeds grow in size rapidly by snowballing. The dip in the bulk density of the seeds (Fig. 32) suggests that the deposited layers are quite porous in the beginning but get compacted in due course to... 

Many of these products are appropriate for either machine or hand washing. Most of them are marketed as compact detergents and have an average bulk density of 0.4—0.5 kg/L. 

Bulk density can give information about a material s porosity. Ceramics and powder metals that are made by compaction and sintering have varying degrees of porosity. In structural parts, porosity is undesirable. However, in powdered metal wear parts, porosity is desired for retention of lubrication. 

In soils, the bulk density is an indication of the degree of compaction and also the capacity for holding water, air, and nutrients. Highly compacted soils with low porosity (voids) are desirable for roadbeds and dams, but are not suitable for plant growth. The actual density, or particle density, of soils is determined by the displacement of water of a given mass of soil. 

In this chapter the physical properties of resins related to processing will be described. The chapter and Appendix A4 include physical properties for many resins. These properties include bulk density and compaction, lateral stress ratio, stress at a sliding interface, melting flux, heat capacity, thermal conductivity, and melt density. Some of these properties are easy to measure by many laboratories while others such as the melting flux and stress at a sliding interface can be measured in only a few places using highly specialized equipment. 

To illustrate the compaction process that occurs in an extruder, a Maddock solidification [1] experiment (described in detail in Section 10.3.1) was performed using a 63.5 mm diameter machine [2]. The extruder was operated at a screw speed of 60 rpm with a poly(vinylidene chloride) copolymer (PVDC) powder. After the extruder reached a steady-state operation, screw rotation was stopped and full cooling was applied to the extruder. After several hours of cooling, the screw and PVDC resin were removed from the extruder and the density of the bed was measured using Archimedes s principle. The compaction phenomenon in the extruder is shown by the density measurements of the solid bed in Fig. 4.1. As shown in this figure, the density of the solid bed increased from the feedstock bulk density of 0.73 g/cm to nearly the solid density of 1.7 g/cmT... 

As shown in Fig. 4.1, resin feedstocks have a considerable level of interparticle space that is occupied by air. This level of space and thus the bulk density of the feedstock depend on the temperature, pressure, pellet (or powder) shape, resin type, and the level and shape of the recycle material. For a specific resin feedstock, the bulk density Increases with both temperature and the applied pressure. Understanding the compaction behavior of a resin feedstock is essential for both screw design and numerical simulation of the solids-conveying and melting processes. Screw channels must be able to accommodate the change in the bulk density to mitigate the entrainment of air and the decomposition of resin at the root of the screw. Typically, screw channels are set by using an acceptable compression ratio and compression rate for the resin. These parameters will be discussed in Section 6.1. 

Amorphous HIPS resin pellets compact very little in the temperature range of 25 °C to about 75 °C, a temperature that is about 25 °C below Tg, as shown in Fig. 4.5. The HIPS resin compacts to a much higher degree for temperatures of 25 °C below Tg up to Tg. Like the LDPE resin, the bulk density at 25 °C and zero pressure was measured using the cell shown in Fig. 4.2 at 0.62 g/cmL At temperatures 25 °C below the Tg (100 °C), the bulk modulus of the resin is relatively high, and thus the pellets do not deform easily under pressure. At higher temperatures, how... 

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