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UMBC undergraduate has highly cited paper

November 29, 2018 2:46 PM
UMBC Physics BS graduate, Jonathan McHenry (class of 2009) and Associate Professor Laszlo Takacs’s paper, “Temperature of the milling balls in shaker and planetary mills”, Journal of Materials Science 41, 5246-5249 (2006) ( has recently received renewed interest in the scientific community with 27 citation in the last two years and over 86 overall.

Ball mills are used to prepare fine powders and to induce alloying and chemical reactions via mechanical deformation. Thermal processes are also at play, thus knowing the temperature inside the mill is important, but it had rarely been studied. Thus when Jonathan McHenry measured the temperature increase of the milling balls in two laboratory mills as a summer project some 15 years ago, unique and very valuable information could be obtained. He used a simple calorimeter from the introductory laboratory but made careful corrections for systematic errors. It turned out that if different mills were run at similar milling intensities, the balls warmed up more, when oblique collisions and friction were involved, like in planetary mills, where temperatures over 200 °C were typical, while close-to-normal impacts, dominant in shaker mills, resulted in much less temperature increase.