Particle size distribution — sieving method

The distribution of aggregate sizes is determined by sieving or sieve analysis. The aim of sieve analysis is to determine the aggregate gradation curve. 

2 Grading of filler aggregates, if filler content is 10% Particle shape of coarse aggregates CEN EN 933-10 (2009) Yes  

S Percentage of crushed and broken surfaces in coarse aggregate particles CEN EN 933-5 (2004) Yes Yes 

6 Flow coefficient of aggregates (angularity of fine aggregates) Cleanliness and quality of fines, if fines content 3% CEN EN 933-6 (2004) Yes  

Sand equivalent Physical properties Resistance to fragmentation/crushing CEN EN 933-8 (2012) Yes 

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CEN EN 933-1.2012. Tests for geometrical properties of aggregates - Part 1 Determination of particle size distribution - Sieving method. Brussels CEN. 

The carbon raw material in the form of coke, coal or natural or synthetic graphite is ground and sieved (following calcination at 700-1300°C to control volatiles, if necessary) to give a desired particle size distribution. The distribution depends upon the size of the artifact to be formed and the method of forming. 

The particle-size distribution of two test powders, spherical glass beads and crushed quartz was determined with different types of app (Ref 32), and indicate that the micro-mesh sieve data is in good agreement with those of other methods (Table 6) ... 

The most commonly used methods for detn of the particle size distribution of fine AP are the Micromerograph and Turbidometric Methods. For coarser AP samples standard sieves are used (see below under Specifications)... 

Different methods are available for the determination of the particle-size distribution of powdered solids [30]. These are optical microscopy (usually combined with image analysis), sieve analysis, laser light scattering of suspended particles, and electrical zone sensing. 

The narrower the particle size distribution, the higher in theory is the potential theoretical plate number. A rough sieving is achieved by a water flow, air flow, or a vibration method. A common sieving method is Hamiltonian water flow (Figure 3.4). The particle distribution can be controlled within + 1 jum by this method. A slurry of stationary phase material is allowed to float in the cylinder, and a solvent flows from the bottom to the top. The smaller and lighter particles float to the top of the cylinder and the larger and heavier particles sink to the bottom. The required particles are collected at the top of the cylinder. The selection of suspension solvent and control of the temperature are important. 

Particle size is one of the principal determinants of powder behavior such as packing and consolidation, flow ability, compaction, etc., and it is therefore one of the most common and important areas of powder characterization. Typically, one refers to particle size or diameter as the largest dimension of its individual particles. Because a given powder consists of particles of many sizes, it is preferable to measure and describe the entire distribution. While many methods of size determination exist, no one method is perfect (5) two very common methods are sieve analysis and laser diffraction. Sieving is a very simple and inexpensive method, but it provides data at relatively few points within a distribution and is often very operator dependent. Laser diffraction is a very rapid technique and provides a detailed description of the distribution. However, its instrumentation is relatively expensive, the analytical results are subject to the unique and proprietary algorithms of the equipment manufacturer, and they often assume particle sphericity. The particle size distribution shown in Figure 1 was obtained by laser diffraction, where the curves represent frequency and cumulative distributions. 

Particle Size Distribution. The particle size distribution is determined by conventional sieving or other methods such as laser granulometry (see Section 1.2.1 Particle Size). 

Standard methods were used for the determination of moisture, essential oil (hydrodistillation) and oleoresin (hexane Soxhlet extraction) content of the raw and residual plant materials. The moisture content and yields obtained by different extraction methods are given in Table 1. Volatile oil contents of the fractionated extracts were also determined by steam distillation. The analysis of particle size distribution was performed by passing the ground plant material through sieves of various mesh size and weighing the fraction taken from each tray. 

Microspheres intended for nasal administration need to be well characterized in terms of particle size distribution, since intranasal deposition of powder delivery systems is mostly determined by their aerodynamic properties and particle sizes. Commonly used methods for particle size determinations described in the literature are sieving methods [108], light microscopy [58], photon correlation spectroscopy [66], and laser diffractometry [25,41,53,93], The morphology of the microparticles (shape and surface) has been evaluated by optical, scanning, and transmission electron microscopy [66, 95],... 

Many methods are available for determining particle size in pharmaceutical practice, including microscopy, sieving, sedimentation, and determination of particle volume [19]. Sieve analysis with U.S. standard sieves is widely used to determine the particle size distribution based on powder weight. Sieves are classified according to the number of openings (Table 14) and are generally made of wire cloth woven from brass, bronze, or other suitable wire. 

Before polyacrylamides are sold, the amount of residual acrylamide is determined. In one method, the monomer is extracted from the polymer and the acrylamide content is determined by7 hplc (153). A second method is based on analysis by7 cationic exchange chromatography (154). For dry7 products the particle size distribution can be quickly determined by7 use of a shaker and a series of test sieves. Batches with small particles can present a dust hazard. The percentage of insoluble material is determined in both dry and emulsion products. 

The fineness of the pigment is characterized by the maximum particle size (mentioned in the catalogues as sieve residue according to standardized DIN or ASTM testing methods) and the average particle size D50 measured preferably by laser beam diffraction methods. These methods are not yet standardized and the readings depend very much on the equipment and the testing conditions. Furthermore the particle size distribution can be characterized by the "span , i.e. the width of the distribution curve. 

ASTM C285-88 (Re-approved 1994) Standard test method for sieve analysis of wet milled and dry milled porcelain enamel, for determination of the fineness of frit in wet-or dry-milled porcelain enamels and other ceramic coatings on metals by use of the number 200 or No 325 mesh, 212 ASTM C925-79 (Re-approved 1995) Standard test method for precision electroformed wet sieve analysis of non-plastic ceramic powders, for particle size distribution determination ofpulverized alumina and quartz for particle sizes from 45 pm to 5 pm by wet sieving, 212, 230... 

Sieves sieving and other sizing methods. In Draft of Standard Determination of Particle Size Distribution, Laser Diffraction Methods International Organization for Standardization (ISO) Berlin, Germany. 

The measurement of particle size is a key issue in the formulation of many pharmaceutical products. Particle size distribution is known to directly influence physical properties of powders, such as dissolution rate, powder flow, bulk density, and compressibility. Conventional methods of particle size measurement include sieve analysis and laser diffractometry. ... 

Practically all the methods for determination of the particle-size distribution in the sub-sieve range utilize a fluid-dynamic system based on Stokes law (177) ... 

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