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Friability testing is a laboratory technique used by the pharmaceutical industry to test the durability of tablets during transit. This testing involves repeatedly dropping a sample of tablets over a fixed time, using a rotating wheel with a baffle.
It is similar to friability testing, [1] but they are not the same thing. Tablet hardness testers first appeared in the 1930s. [3] In the 1950s, the Strong-Cobb tester was introduced. It was patented by Robert Albrecht on July 21, 1953. [4] and used an air pump. The tablet breaking force was based on arbitrary units referred to as Strong-Cobbs. [3]
The basic tests measure the following parameters: wet tensile strength, cone jolt, mouldability, friability, moisture content, permeability, green compression strength, compactibility, loss on ignition, volatiles content, grain size & distribution, dust (dead clay) content, and active clay content, impact strength .
Friability and abrasion testing is performed in rotating testing drums, designed according to the pharmacopeia. The measured parameter is weight loss before and after testing and tumbling the tablets at a particular time and speed. In the friability test drum tablets are being carried up by a "shovel" and dropped.
Variations in the electrical conductivity and magnetic permeability of the test object, and the presence of defects causes a change in eddy current and a corresponding change in phase and amplitude that can be detected by measuring the impedance changes in the coil, which is a telltale sign of the presence of defects. [5]
The test reports loss of mass to abrasion and impact, expressed as a percentage of initial sample mass. [7] Maximum acceptable loss for the base course of the road is 45%; the more demanding surface course must be 35% or less. [1] The test was developed by the city engineers of Los Angeles in the 1920s. [8]
The Rockwell hardness test is a hardness test based on indentation hardness of a material. The Rockwell test measures the depth of penetration of an indenter under a large load (major load) compared to the penetration made by a preload (minor load). [1] There are different scales, denoted by a single letter, that use different loads or indenters.
The Vickers test can be used for all metals and has one of the widest scales among hardness tests. The unit of hardness given by the test is known as the Vickers Pyramid Number (HV) or Diamond Pyramid Hardness (DPH). The hardness number can be converted into units of pascals, but should not be confused with pressure, which uses the same units ...