Sieved Materials

The particle influences the time and efficiency of sieving. Issues relate to the sample's mass, particle size distribution, particle density, particle shape, friability, the tendency to aggregate and electrostatic properties. Specific procedures have been developed for particular materials.

Obtaining a representative sample or subsample for seive analysis is a key step; this is a particular issue where nonuniformity is extreme or segregation of the sample may occur. It may sometimes be necessary to settle for reproducible sampling with the goal of making comparisons on a relative basis.

Sample mass influences the efficiency of sieving and the time needed for a sieving operation. At high loadings, blinding of the sieve may be more important as well as increased breakdown of friable samples.

Particle size distribution has several effects on the efficiency of sieving. These effects, if they exist, may depend on the choice of sieves. Particles which are slightly oversize may lodge in the sieve, blocking the aperture from participating in the sieving process. This 'blinding' of the sieve reduces the overall efficiency of sieving or increases the time needed to achieve separation.

Sample friability can also influence separation. Friability is the tendency of particles to break apart. The process of agitation and sieving may change the particle size distribution for friable samples. Longer sieving times or larger amplitude agitation increase these effects. Ultimately, the goal of the sieving operation must be compared to the effect of sieving on the underlying size distribution.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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