Particle size, bulk density

The crospovidone monograph of Ph.Eur. 5 requires a functional classification into Type A (= non-micronized product) and Type B (= micronized product) by means of a particle size measurement in identification test D. 

The best method of the determination of the particle size distribution of the different crospovidone types is the light diffraction measurement (e.g. Malvern Master Sizer, see Fig. 63 and 64). The particle size distribution of normal crospovidone also can be measured by sieving or air jet screening. In this dry sieving method more than 50 % of the particles are coarser than 50 pm without any swelling. Therefore even with this dry method it corresponds clearly to the definition of Type A of the Ph.Eur. monograph. 

The particle size distribution of micronized crospovidone can be measured as suspension in water or cyclohexane by a Malvern Master Sizer and there is no significant influence of the solvent. If almost all particles are finer than 50 pm it is classified as Type B of Ph.Eur. 

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Belt with nucleonic sensor <25 (or <0.3 m3/s) 0.5 to 1 Preferred when material is difficult to handle, e.g. corrosive, hot, dusty, or abrasive. Accuracy greatly improved when particle size, bulk density, and moisture content are constant, when belt load is 70-100 per cent of maximum. 

THROUGHPUT . PARTICLE SIZE BULK DENSITY SOLIDS ARE SOLIDS ... 

Powder characteristics (mean particle size, bulk density, etc.)... 

Name Description Particle Size Bulk Density, G/ml... 

The conversion of liquid dairy streams into powders is an important processing operation in the dairy industry. The removal of water from a dairy stream during concentration and drying can influence the functional properties of the resultant powders. This depends on factors such as the composition of the stream to be dried, the type of driers used, and the conditions of drying. Both the physical characteristics of the powders (e.g., particle size, bulk density, occluded air) and their functional properties can be affected by drying (Tong, 2001). 

Segregation. The problem of segregation occurs when a bulk soHd composed of different particle sizes or densities separates. The result can be quite serious if uniform density or mixed material is required for a process. 

Particle size for which 60% of the matrix is smaller than that size Bulk density... 

Also, it seems that most of these properties are interdependent. For example, deaeration and permeability (Mainwaring and Reed, 1987) and perhaps the bulk density ratio (Jones and Mills, 1989) seem to provide an adequate mechanism to detect changes in material performance due to different particle size distribution, density and/or shape. However, possibly the greatest disadvantage or limitation of these empirical techniques is the need to standardize the experimental apparatus and techniques. For exam-... 

When evaluating a material for the purpose of establishing dense-phase and long-distance suitability, it is important to undertake all the necessary tests (e.g., particle sizing, particle and bulk densities, fluidization and deaeration). Also, if possible, it is useful to compare such results with those obtained on previously conveyed similar materials (e.g., fly ash). However, it should be noted that such an evaluation only is a qualitative one and it is not possible to predict say, minimum air flows or pipeline pressure drop based on such data (i.e., pilot-scale tests normally are required to confirm minimum velocities, friction factors, etc., especially over long distances and for large-diameter pipes). 

Particle size distribution Density (bulk and tapped)... 

Grade Hydraxy-prapaxy cantent (%) Angle of repase (°) Average particle size (pm) Density (bulk) (g/cm ) Density (tapped) (g/cm )... 

CDioss is indirect proportional to the relaxation time t (eqs. 6.7 and 6.9). With one exception of the R/C=1500 sample with a density 880 kg/m C0, xw increases and the relaxation time decreases with density. The material parameters for water and RF fulfill the requirements for the approximation according to eq. 6.9. If one takes the decreasing primary particle size with density (tables 1 and 2) as a guideline for the layer thickness of the bulk RF-material (di in eq. 6.9), it is obvious that the layer thickness of water (d2 in eq. 6.9) has to decrease further to allow for a decrease in x. This reduced thickness of the water layers compensates the decrease in primary particle size and causes the shifts in C0 . 

Particle size, particle structure, bulk density 2.2.4.1... 

Research and development work started in 1972 led to the conclusion that while many of the above disadvantages could be reduced or eliminated by drying and cleaning the RDF, ECO-FUEI I still had a large size particle, low bulk density (4-7 lb/cu ft), and was not suited to storage, retrieval and transportation. 

These generally follow the same rule as used in the example above, however, one major difference is that one needs to know the fluidizing velocity of the wet cake or back mixed material to dry. The factors involved in determining the fluidizing velocity are particle size, particle density, particle shape, bulk density, and medium for fluidization. Since there are too many factors to place into a reliable equation, the most expedient method of... 

Definition of the API in terms of its critical quality attributes. Among the attributes that should be considered are chemical purity qualitative and quantitative impurity profiles physical characteristics such as particle size, bulk and tap density polymorphic forms moisture and solvent content homogeneity and microbial quality (if the product is susceptible to microbial contamination). 

Steps that cause changes in surface area, particle size, bulk and tap density or homogeneity. 

List the dry product properties, such as powder size distribution, particle shape, bulk density, specific heat, glass transition temperature, hygroscopicity, powder flammability. 

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