This project supports participation of students and early career researchers in a short course "Microstructural Analysis and EBSD Applications in Earth Sciences" to be held at San Francisco State University. The short course will provide a brief introduction to a unique mathematical approach to analyze integral X-ray, neutron or synchrotron diffraction pole intensity data as well as individual orientation data from electron backscatter diffraction (EBSD), Ice Fabric Analyzer or optical universal stage, and hands-on exercises with Windows/Mac/Linux systems applying the free and open MATLAB toolbox MTEX for texture analysis. In particular, estimation of an orientation distribution function and its properties as harmonic coefficients, volume portions, texture index, entropy, calculation of anisotropic properties, for example,. from the different kinds of data and grain reconstruction from EBSD data will be included. An MTEX workshop has never been offered in the U.S. Workshop participants will leave the workshop with some preliminary results from practical sessions under expert instruction and will be able to immediately start using MTEX.
Quantitative microstructural analysis is an increasingly important aspect of many fields in the earth sciences including structural geology, experimental rock deformation, and seismology, for example. The wider availability of EBSD, in particular, presents researchers with much larger and more complex data to analyze. Training the next generation in the software tools necessary for such analysis is critical.
This award supported a 3-day training workshop "Texture Analysis with MTEX" at San Francisco State University for earth and materials scientists. The goal of the training workshop was to introduce graduate students and junior faculty from across the U.S. to the open-source MATLAB toolbox "MTEX" for texture analysis. MTEX is a free Matlab toolbox for analyzing and modeling crystallographic textures by means of electron backscatter diffraction (EBSD) or pole figure data. MTEX uses a unique mathematical approach to analyze integral X-ray, neutron or synchrotron diffraction pole intensity data as well as individual orientation data from EBSD analysis, Ice Fabric Analyser, or optical universal stages. Participants gained several hours of hands-on exercises with Windows/Mac/Linux systems applying the MATLAB toolbox MTEX for texture analysis. All attendees brought their own laptop computers and texture data to use in the training exercises. The exercises provided an introduction to MTEX functions and ample opportunities for guided and supervised learning by doing practical applications. In particular, training included estimation of an orientation distribution function (ODF) and its properties as harmonic coefficients, volume portions, texture index, entropy, calculation of anisotropic properties, etc. from the different kinds of data and grain reconstruction from EBSD data. The organization of the 3-day training workshop took advantage of the Fall Meeting of the American Geophysical Union in San Francisco, CA, and took place immediately prior to this event. All participants paid a small registration fee to cover expenses that were not allowable by the NSF. NSF funding covered transportation, lodging, and per diem expenses for all graduate students, junior faculty members, and researchers from underrepresented groups so that they were able to attend this workshop. As a result of the training workshop, US researchers were exposed to a new research community, thus the workshop enabled new interactions between junior and senior researchers that would have otherwise not been possible. Since this training workshop took place, a new version of the MTEX toolbox was released - MTEX 4.0.beta1 - which is one of the biggest rewrites in MTEX history. MTEX 4.0 adds new features such as explicit grain boundary handling; support for all 32 Laue groups, including differentiation between 11m, 1m1, m11, -3m1, -31m, etc.; improved visualization, e.g., individual colorbars for pole figure plot; and many small improvements. Beside these visible changes MTEX 4.0 has seen major internal changes. MTEX 4.0 switched to the new class system of MATLAB to keep compatibility with future releases of MATLAB. The switch to the new class system has also many advantages in the usability of MTEX. The major outcomes from this 3-day texture analysis workshop include: 1. Thirty-six mostly graduate students and junior faculty from twenty-five universities attended the workshop. 2. Twenty-seven participants received financial support from NSF to attend the workshop. 3. The two invited speakers, David Mainprice and Helmut Schaeben, presented highly informative talks on using the MTEX toolbox in MATLAB, and explaining the mathematics used in the development of MTEX algorithms. 4. Participants worked one-on-one with the workshop leaders, to process their individual research data using MTEX. 5. All training and supporting materials are available online – the training documents are available at David Mainprice’s web site (https://sites.google.com/site/davidmainprice/home/teaching-documents), and a new MTEX Toolbox website (http://mtex-toolbox.github.io/) contains all downloads, documentation, related publications, and installation information.
