Density, powder apparent

When electrical conductivity is used to investigate the compressibility of boride powders at a pressure of 0.19-1.7 X 10 N m , the variation of the specific electrical conductivity x with the relative density 0 (apparent density of the blank/density of the bulk material) is ... 

Porosity of packed powder Apparent agglomerate or granule density g/cnr Ib/ft ... 

Properties Powder. Apparent bulk density, (fully settled, light) 0.6-0.8 g/cc dense, 1.2-1.4 g/cc high neutron absorption. 

Compressibility. This is the ratio of green density to apparent density. The ratio increases with increasing pressure until a limit is reached. Compressibility of a powder is an important criterion for press and die design. 

Dihydrate, hygroscopic granules, flakes or powder. Apparent (bulk) density 0.835. Freely sol in water, alcohol. Commercial grades contain 73-80% CaCl2. Keep well closed. 

White, free-flowing powder. Sansitive to air and moisture. Dec by water. Sol in methanol, ethanol. Also exists in solvated form, CH,ONa.2CH3OH, white powder. Apparent density of solvent -free material about 4.6 lb/gal. 

The apparent density or volumetric mass is defined as the mass per unit volume of powder [1]. It is well known that copper powders characterized with high values of specific surface exhibit low apparent density. Powder particles from the same fraction of different powders occupy approximately the same volume, but the stmcture of the metallic copper can be considerably different with apparent densities, as weU as the different specific surfaces [42,43]. Obviously, the more disperse the powder particles are, the smaller is the apparent density of the copper powder, and the larger is the specific surface. 

Bulkladung (Transport) bulk container Schilttgutbehalter bulk density (BD)/ apparent density/ gross density (powder density) Rohdichte, Schiittdichte bulk diffusion Massendiffusion, Gesamtduffusion bulk factor Filllfaktor,... 

Adsorbent Material Density, do, g/cm3 Powder apparent density, dp, g/ sm Medium size, mcm Porosity m, 1-dp/ do... 

Bulk Density. Bulk density, or the apparent density, refers to the total amount of space or volume occupied by a given mass of dry powder. It includes the volume taken up by the filler particles themselves and the void volume between the particles. A functional property of fillers in one sense, bulk density is also a key factor in the economics of shipping and storing fillers. 

Apparent Density. This term refers to the weight of a unit volume of loose powder, usually expressed in g/cm (l )- The apparent density of a powder depends on the friction conditions between the powder particles, which are a function of the relative surface area of the particles and the surface conditions. It depends, furthermore, on the packing arrangement of the particles, which depends on the particle size, but mainly on particle size distribution and the shape of the particles. 

The characteristics of a powder that determine its apparent density are rather complex, but some general statements with respect to powder variables and their effect on the density of the loose powder can be made. (/) The smaller the particles, the greater the specific surface area of the powder. This increases the friction between the particles and lowers the apparent density but enhances the rate of sintering. (2) Powders having very irregular-shaped particles are usually characterized by a lower apparent density than more regular or spherical ones. This is shown in Table 4 for three different types of copper powders having identical particle size distribution but different particle shape. These data illustrate the decisive influence of particle shape on apparent density. (J) In any mixture of coarse and fine powder particles, an optimum mixture results in maximum apparent density. This optimum mixture is reached when the fine particles fill the voids between the coarse particles. 

Tap Density. Tapping a mass of loose powder, or more specifically, the appHcation of vibration to the powder mass, separates the powder particles intermittently, and thus overcomes friction. This short-time lowering of friction results in an improved powder packing between particles and in a higher apparent density of the powder mass. Tap density is always higher than apparent density. The amount of increase from apparent to tap density depends mainly on particle size and shape (see Table 4). 

Inasmuch as friction conditions determine the flow characteristics of a powder, coarser powder particles of spherical shape flow fastest and powder particles of identical diameter but irregular shape flow more slowly. Finer particles may start to flow, but stop after a short time. Tapping is needed in order to start the flow again. Very fine powders (fine powder particles to coarser ones may increase the apparent density, but usually decreases the flow quality. Metal powders having a thin oxide film may flow well. When the oxide film is removed and the friction between the particles therefore increases, these powders may flow poorly. 

Determination of Apparent Density ofFree-FlowingMetal Powders Using the Hall Apparatus MPIF Standard No. 04, and Determination of Apparent Density of Non-Free Flowing Metal Powders Using the Camej Apparatus, No. 4, Metal Powder Industries Federation, Princeton, N.J., 1992. 

Potassium Methylate. Potassium methoxide [865-33-8] KOCH, mol wt 70.13, is a fine, free-flowing, yellowish-white, caustic, hygroscopic powder purity 96.5—99% powder density after loose shaking, 0.75 g/mL apparent density (packing weight), 1.00 g/mL medium grain size, 0.05 —0.8 mm easily soluble in alcohols (33% in methanol at 20°C), insoluble in hydrocarbons. 

In addition to surface area, pore size distribution, and surface chemistry, other important properties of commercial activated carbon products include pore volume, particle size distribution, apparent or bulk density, particle density, abrasion resistance, hardness, and ash content. The range of these and other properties is illustrated in Table 1 together with specific values for selected commercial grades of powdered, granular, and shaped activated carbon products used in Hquid- or gas-phase appHcations (19). 

Foam Insulation Since foams are not homogeneous materials, their apparent thermal conductivity is dependent upon the bulk density of tne insulation, the gas used to foam the insulation, and the mean temperature of the insulation. Heat conduction through a foam is determined by convection and radiation within the cells and by conduction in the solid structure. Evacuation of a foam is effective in reducing its thermal conductivity, indicating a partially open cellular structure, but the resulting values are stiU considerably higher than either multilayer or evacuated powder insulations. 

Typical polarization curves for alkaline fuel cells are shown in Fig, 27-63, It is apparent that the all aline fuel cell can operate at about 0,9 and 5()() rnA/cnr current density. This corresponds to an energy conversion efficiency of about 60 percent IIII, The space shuttle orbiter powder module consists of three separate units, each measuring 0,35 by 0,38 by I rn (14 by 15 by 40 in), weighing 119 kg (262 lb), and generating 15 kW of powder. The powder density is about 100 W/L and the specific powder, 100 W/kg,... 

The bulk factor (i.e. ratio of the density of the moulding to the apparent powder density) of powder is usually about 2-3 but the high-shock grades may have bulk factors of 10-14 when loo.se, and still as high as 4-6 when packed in the mould. Powder grades are quite easy to pellet, but this is difficult with the fabric-filled grades. 

Density, apparent The weight in air of a unit volume of material including voids usually inherent in the material. Also used is the term bulk density that is commonly used for materials such as molding powders. 

Apparent Density (Type A powder only) The apparent density of Type A powder shall not be less than 0.80g/cc when detd using a Scott Volumeter... 

The resulting product has a low apparent density. Other synthesis techniques have been reported (192), mainly the reaction of a stoichiometric mixture of P3N5 and P4O10, heated at 780°C for 48 h, which directly results in a crystalline powder (193). Crystallization of X-ray amorphous PON produced using the other preparation methods is obtained after heating the powder in an evacuated quartz ampoule at 700-800°C for several days. 

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