Articles by Matthew Whitaker in JoVE
Stress Distribution During Cold Compression of Rocks and Mineral Aggregates Using Synchrotron-based X-Ray Diffraction Cecilia S.N. Cheung1,2, Donald J. Weidner1, Li Li1, Philip G. Meredith3, Haiyan Chen1, Matthew Whitaker1, Xianyin Chen4 1Mineral Physics Institute, Department of Geoscience, Stony Brook University, 2Geological Engineering, Department of Civil and Environmental Engineering, University of Wisconsin-Madison, 3Rock and Ice Physics Laboratory, Department of Earth Sciences, University College London, 4Department of Chemistry, Stony Brook University We report detailed procedures for compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus coupled with synchrotron X-radiation. Such experiments allow quantification of the stress distribution within samples, that ultimately sheds light on compaction processes in geomaterials.
Other articles by Matthew Whitaker on PubMed
Deformation T-Cup: a New Multi-anvil Apparatus for Controlled Strain-rate Deformation Experiments at Pressures Above 18 GPa The Review of Scientific Instruments. | Pubmed ID: 25173308 A new multi-anvil deformation apparatus, based on the widely used 6-8 split-cylinder, geometry, has been developed which is capable of deformation experiments at pressures in excess of 18 GPa at room temperature. In 6-8 (Kawai-type) devices eight cubic anvils are used to compress the sample assembly. In our new apparatus two of the eight cubes which sit along the split-cylinder axis have been replaced by hexagonal cross section anvils. Combining these anvils hexagonal-anvils with secondary differential actuators incorporated into the load frame, for the first time, enables the 6-8 multi-anvil apparatus to be used for controlled strain-rate deformation experiments to high strains. Testing of the design, both with and without synchrotron-X-rays, has demonstrated the Deformation T-Cup (DT-Cup) is capable of deforming 1-2 mm long samples to over 55% strain at high temperatures and pressures. To date the apparatus has been calibrated to, and deformed at, 18.8 GPa and deformation experiments performed in conjunction with synchrotron X-rays at confining pressures up to 10 GPa at 800 °C .
DIASCoPE: Directly Integrated Acoustic System Combined with Pressure Experiments-A New Method for Fast Acoustic Velocity Measurements at High Pressure The Review of Scientific Instruments. | Pubmed ID: 28372428 A new experimental system to measure elastic wave velocities in samples in situ under extreme conditions of pressure and temperature in a multi-anvil apparatus has been installed at Beamline 6-BM-B of the Advanced Photon Source at Argonne National Laboratory. This system allows for measurement of acoustic velocities via ultrasonic interferometry, and makes use of the synchrotron beam to measure sample densities via X-ray diffraction and sample lengths using X-radiographic imaging. This system is fully integrated into the automated software controls of the beamline and is capable of collecting robust data on elastic wave travel times in less than 1 s, which is an improvement of more than one to two orders of magnitude over existing systems. Moreover, this fast data collection time has been shown to have no effect on the obtained travel time results. This allows for more careful study of time-dependent phenomena with tighter snapshots in time of processes that would otherwise be lost or averaged out in other acoustic measurement systems.