Particle density pycnometer volume

Particle density is an important parameter in defining the aerodynamic behaviour of airborne particles. Small quantities of selected batches (ca. Ig of FS3, FS4, FS5 and FS6) were placed in the sample chamber of a helium pycnometer (model 1305 Multivolume Helium Pycnometer, Micromeritics Ltd, Basingstoke, UK), and the particle density determined from the volume of helium displaced, assuming there were no inaccessible voids within the particles. The four measurements (each of which was the mean of 4 to 6 separate determinations (Table 3)) were within the density range of 2.91 to 3.26 X 1Q3 kg m-3 quoted for natrojarosite. These studies confirm the validity of the x-ray diffraction measurements, and also indicated that the particles were substantially free of internal voids. 

True Density or Specific Gravity. The average mass per unit volume of the individual particles is called the tme density or specific gravity. This property is most important when volume or mass of the filled composition is a key performance variable. The tme density of fillers composed of relatively large, nonporous, spherical particles is usually determined by a simple Hquid displacement method. Finely divided, porous, or irregular fillers should be measured using a gas pycnometer to assure that all pores, cracks, and crevices are penetrated. 

The particle shape was determined by visual inspection of the particles. To determine the particle diameter xp, the volume of individual particles was measured in a He-pycnometer and the diameter of the sphere possessing the same volume was calculated. The solid density /0p was measured in the He-pycnometer as well. The Vicker s hardness //y was determined in a microhardness tester while Young s modulus E and yield stress ay were given by the manufacturer. Finally, the J-integral value Jqci which... 

Calculate the porosity and the mean pore radius. The particle porosity may be readily determined by a helium pycnometer and a mercury porosimeter. In the pycnometer, the solid skeletal volume Vs is obtained. The skeletal density ps is found from the sample weight Ws ... 

Density of a substance may be defined as the weight of a substance per unit volume. In principle, the bulk density of agglomerated particles in the slurry can offer an indirect measurement of the abrasive particle hardness. The bulk density of the particle can be calculated by using Equation 7.16, excluding the open pores and voids from the volume calculation, where p stands for the specific gravity of the slurry measured using a pycnometer [77]. 

The bulk density of a powder is obtained by dividing its mass by the bulk volume it occupies. The volume includes the spaces between particles as well as the envelope volumes of the particles themselves. The true density of a material (i.e., the density of the actual solid material) can be obtained with a gas pycnometer. The bulk density of a powder is not a definite number like true density or specific gravity but an indirect measurement of a number of factors, including particle size and size distribution, particle shape, true density, and especially the method of measurement. Although there is no direct linear relationship between the flowability of a powder and its bulk density, the latter is extremely important in determining the capacity of mixers and hoppers and providing an easily obtained valuable characterization of powders. 

The density of packing of the particles is of primary importance in considering the behavior of sediments. There are four ways to determine sample volume in practice—(A) wet total volume from a constant volume sampling ring to extract sample cylinders from soft sediments (V,Ring), (B) wet total volume from the gas pycnometer (V,pyJ, (C) dry volume from the gas pycnometer (V pyJ, and (D) volume of sampling tube (V,). The three volume... 

True Density - True density is the mass per unit volume of a fertilizer material, excluding voids between particles and the pores within the particles. It is of interest in process control and design of process equipment. The true density carr be determined with an air-comparison pycnometer. The pycnometer has two sample chambers of equal size. One chamber is flooded with a measured volume of air. The other chamber is filled with a weired amount of the ground test sample and then flooded with a measured volume of air. The difference in air volumes is equivalent to the sample volume. The sample weight and volume are used to calculate the true density. Figure 18.6 is an illustration of a Beckman air-comparison pycnometer. Typical true density values for some common fertilizer materials are listed in Table 18.4. 

Apparent density also known as particle or mercury density, is defined as the mass of unit volume of the carbon particle, including its pore system. From this value it is possible to obtain the bed porosity. This bed porosity, or void volume is an important value with respect to the flow characteristics of the activated carbon bed. The method uses a pycnometer. If both apparent and real densities are known, the difference of their inverses will provide the total pore volume of the activated carbon. 

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