(264d) A New Microtriaxial Tester for the Characterization of Fine Particulate Systems

As a continued effort in the exploration of new avenues in the concepts and designs of powder flow testers, a new microtriaxial tester was designed. As we focus on smaller particle sizes, or as confining loads decrease, the influence of the interparticle cohesive forces increases. Thus, the potential for significant volume change upon shearing also increases. These changes can be captured very reliably using an enhanced triaxial tester and volume change device. Many times only a limited quantity of powder is available for testing and sometimes it takes months to manufacture these exotic powders in a laboratory environment for research and development purposes. A good example is pharmaceutical powders that could cost thousands of dollars a gram. Thus, there is a critical need for a device that may be able to test tiny specimens of powders that would be about the size of a pea and would weigh only a few milligrams. Currently, there are no powder flow testers that can deal with such small quantities; therefore a microtriaxial tester would be an extremely valuable tool in powder mechanics. Pharmaceutical companies are very much interested in micro powder flow testers that are currently not available. They can not measure bulk mechanical properties of powders that are only available in small quantities. It is important for these industries to be able to control compaction, porosity, and quality of their products manufactured from granular materials prior to production. The possibility of measuring bulk properties of powders that are only available on a laboratory scale will speed up the design and development of transportation and handling equipment necessary for going from the development stage to the actual production stage.