Bulk density volume

Ushakumari et al. (2007) developed a process for the preparation of expanded ragi. After parboiling and decortication, the grains were conditioned to 40% moisture, flattened in a roller flaker, and then toasted in salt maintained at 220-225 °C for 6 s. Shape factor (ratio of measurements on two peripendicular axes), the expansion ratio (ratio of the volume of expanded millet to that of the decorticated millet of equal weight), apparent bulk density (volume of known weight of expanded millet), and sensory characteristics were the criteria used. The optimum conditions to prepare a product with the highest expansion ratio was then determined. 

The as-prepared aerogels were characterized by measurement of the bulk density, volume shrinkage, and porosity. Table 4.2 sununarizes those physical properties for MTMS-and MTES-deri ed aerogels. 

Porosity and pore-size distributions were determined by gas adsorption and immersion calorimetry, with the measurement of helium and bulk densities. Volumes of micropores were calculated using the Dubinin-Radushkevich (DR) equation (Section 4.2.3) to interpret the adsorption isotherms of N2 (77 K), CO2 (273 K) and n-C4H o (273 K). Volumes of mesopores were evaluated by subtracting the total volume of micropores from the amount of nitrogen adsorbed at p/p° = 0.95. The two density values for each carbon were used to calculate the volume of the carbon skeleton and the total volume of pores (including the inter-particle space in monolithic disks). Immersion calorimetry of the carbon into liquids with different molecular dimensions (dichloromethane 0.33 run benzene 0.37 nm and 2,2-dimethylbutane 0.56 nm) permits the calculation of the surface area accessible to such liquids and subsequent micropore size distributions. The adsorption of methane has been carried out at 298 K in a VTI high-pressure volumetric adsorption system. Additional techniques such as mercury porosimetry and scanning electron microscopy (SEM) have also been used for the characterization of the carbons. 

The formation density log is the main tool for measuring porosity. It measures the bulk density of a small volume of formation in front of the logging tool, which is a mixture of minerals and fluids. Providing the rock matrix and fluid densities are known the relative proportion of rock and fluid (and hence porosity) can be determined. 

Polyurethane is pulverized to iacrease its bulk density, mixed with 30—80% of a thermoplastic mol ding material, gelled, and then granulated to give coated urethane foam particles 0.1 to 0.15 mm in size (48). The particle bulk density is three times that of the polyurethane, while the volume is 15% less. This material may be injection molded or extmsion molded into products (49). Other technologies for recycling polyurethanes have also been reported. 

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. 

When determining bulk density, a distinction should be made between loose bulk density and tap density, eg, ASTM B527-81. The latter is a measure of the influence of settling on filler volume at constant mass. 

Solid Density. SoHds can be characterized by three densities bulk, skeletal, and particle. Bulk density is a measure of the weight of an assemblage of particles divided by the volume the particles occupy. This measurement includes the voids between the particles and the voids within porous particles. The skeletal, or tme soHd density, is the density of the soHd material if it had zero porosity. Fluid-bed calculations generally use the particle... 

Specific gravity is the most critical of the characteristics in Table 3. It is governed by ash content of the material, is the primary deterrninant of bulk density, along with particle size and shape, and is related to specific heat and other thermal properties. Specific gravity governs the porosity or fractional void volume of the waste material, ie. 

In addition, because of the extreme variation in the bulk density of products, use of the standard 19-L (5-gal), 38-L (10-gal), 61-L (16-gal), 114-L (30-gal), and 208-L (55-gal) metal dmms often results in excessive outage. Fiber dmms, in contrast, are available in a wide range of sizes, and can be sized to meet product volumes, thus allowing for Httle outage as weU as saving storage and shipping space. 

Other Fiber Evaluation Methods. The extent of fiber separation (fiber openness) is an important evaluation criteria that is commonly measured by several techniques, namely ak permeabiUty, adsorbed gas volume, bulk density, and residence (compression and recovery). The adsorption and retention of kerosene is also used as a measure of fiber openness and fiber adsorption capacity (34). 

Rapid heating of either borax decahydrate or pentahydrate causes the crystal to dissolve before significant dehydration, and at about 140°C, puffing occurs from rapid vaporisation of water to form particles having as high as 90% void volume and very low bulk density (78). 

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). 

Stmcture is usually measured by a void volume test such as the absorption of dibutyl phthalate (DBPA) (15), or by bulk density measurements of the carbon black under compression. In order to eliminate the effects of pelletizing conditions the DBPA test has been modified to use a sample that has been precompressed at a pressure of 165 MPa (24,000 psi) and then broken up four successive times (24M4) (16). This procedure causes some aggregate breakdown and is claimed to more closely approximate the actual breakdown that occurs duting mbber mixing. 

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... 

Diatomaceous Silica Filter aids of diatomaceous silica have a dry bulk density of 128 to 320 kg/m (8 to 20 Ib/fU), contain paiiicies mostly smaller than 50 [Lm, and produce a cake with porosity in the range of 0.9 (volume of voids/total filter-cake volume). The high porosity (compared with a porosity of 0.38 for randomly packed uniform spheres and 0.2 to 0.3 for a typical filter cake) is indicative of its filter-aid ability Different methods of processing the crude diatomite result in a series of filter aids having a wide range of permeability. 

Bulk density is easily measured from the volume occupied by the bulk solid and is a strong func tion of sample preparation. True density is measured by standard techniques using liquid or gas picnometry Apparent (agglomerate) density is difficult to measure directly. Hink-ley et al. [Int. ]. Min. Proc., 41, 53-69 (1994)] describe a method for measuring the apparent density of wet granules by kerosene displacement. Agglomerate density may also be inferred from direcl measurement of true density and porosity using Eq. (20-42). 

The starting point in bag-size determination is the weight or volume of product to be packaged and its bulk density (aerated and settled). 

From isotherm measurements, usually earried out on small quantities of adsorbent, the methane uptake per unit mass of adsorbent is obtained. Sinee storage in a fixed volnme is dependent on the uptake per unit volume of adsorbent and not on the uptake per unit mass of adsorbent, it is neeessary to eonvert the mass uptake to a volume uptake. In this way an estimate of the possible storage capacity of an adsorbent can be made. To do this, the mass uptake has to be multiplied by the density of the adsorbent. Ihis density, for a powdered or granular material, should be the packing (bulk) density of the adsorbent, or the piece density if the adsorbent is in the form of a monolith. Thus a carbon adsorbent which adsorbs 150 mg methane per gram at 3.5 MPa and has a packed density of 0.50 g/ml, would store 75 g methane per liter plus any methane which is in the gas phase in the void or macropore volume. This can be multiplied by 1.5 to convert to the more popular unit, V/V. 

All commercial carbons have been made for uses other than natural gas storage. They are for the most part granular materials and pack into vessels with a substantial inter-particle void volume which results in low bulk densities. Some... 

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