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| Fundamental structure-property
research The group conducts research into the structures and thermal behavior of natural zeolites and clays using X-ray powder diffraction and thermal analysis. Zeolite structures are analyzed, often under a variety of temperatures and humidities, using Rietveld refinement and structure solution methods. More detailed structural studies often involve the combination of X-ray and neutron methods with infrared and/or Raman spectroscopic data. The thermal analytical research includes measurement of water adsorption isotherms and calorimetric measurement of heats of adsorption. These adsorption and calorimetric data are often combined with the X-ray structural data to provide a complete picture of zeolite or clay hydration and dehydration. For more information, contact:
Quantitative mineralogical analysis EES-1 researchers use advanced X-ray powder diffraction methods to determine the mineralogical makeup of geologic materials, particularly fine-grained volcanic rocks and their alteration products. They have developed state-of-the-art techniques to correct for important systematic errors and routinely produce high-precision mineralogical analyses. EES-1 also has a well developed capability in the mineralogic analysis of microscopic samples, and samples less than 0.1 mg in weight are routinely analyzed. In addition, methods have been developed for the detection of trace amounts of minerals in mixtures. For example, we routinely determine the presence or absence of erionite in zeolitic samples at a detection limit of ~300 ppm. In conjunction with the structural studies of clays and zeolites, the group has pioneered the development of the Rietveld quantitative analysis method. With this method, an entire observed powder diffraction pattern is fit using a diffraction pattern calculated using the crystal structures of the minerals in the sample. This method has the capability to provide analyses of mineral mixtures with accuracies approaching those obtained with traditional chemical methods. For more information, contact:
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