Automated Reconstruction of Spherical Kikuchi Maps

An automated approach to fully reconstruct spherical Kikuchi maps from experimentally collected electron backscatter diffraction patterns and overlay each pattern onto its corresponding position on a simulated Kikuchi sphere is presented in this study. This work demonstrates the feasibility of warping any Kikuchi pattern onto its corresponding location of a simulated Kikuchi sphere and reconstructing a spherical Kikuchi map of a known phase based on any set of experimental patterns. This method consists of the following steps after pattern collection: (1) pattern selection based on multiple threshold values; (2) extraction of multiple scan parameters and phase information; (3) generation of a kinematically simulated Kikuchi sphere as the “skeleton” of the spherical Kikuchi map; and (4) overlaying the inverse gnomonic projection of multiple selected patterns after appropriate pattern center calibration and refinement. The proposed method is the first automated approach to reconstructing spherical Kikuchi maps from experimental Kikuchi patterns. It potentially enables more accurate orientation calculation, new pattern center refinement methods, improved dictionary-based pattern matching, and phase identification in the future.

Interpreting the Tri Mandala Concept on the Motif of Gringsing Wayang Kebo Woven Cloth

Gringsing wayang kebo woven cloth is one of specialty cloths owned by Tenganan Pegringsingan Village, Manggis Sub-district, Karangasem Regency, Bali. This research aims to interpreting the Tri Mandala concept on the motif of gringsing wayang kebo woven cloth. The approach of this research is descriptive qualitative. Techniques for collecting data are observation, interview, and documentation, data analysis is using interactive analysis model and the validity of the data will be confirmed with triangulation technique. The result of this research shows that the motif of gringsing wayang kebo follows the of Tri Mandala concept that consists of 3 parts, Main pattern, Center pattern, and edge pattern. The motifs consisted of each pattern are 1). The motif on the main pattern consists of the plus, swastika, building, and scorpion motif; 2). The motif on the center pattern consists of an animal motif, floral, mountain, wayang; and; 3). The motif on the edge pattern consists of plus sign (+) and sun.

Resolving pseudosymmetry in γ-TiAl using cross-correlation electron backscatter diffraction with dynamically simulated reference patterns

Pseudosymmetry is a phenomenon that occurs when grains with different lattice parameters produce nearly identical diffraction patterns such that conventional electron backscatter diffraction (EBSD) techniques are unable to unambiguously differentiate the lattice orientations. This commonly occurs in materials with near-unity tetragonality, such as γ-TiAl. The current study uses cross-correlation EBSD to resolve pseudosymmetry in γ-TiAl. Three dynamically simulated reference patterns are generated for each point in the scan, one for each of the three potential pseudosymmetric orientations, which are subsequently correlated with the original pattern using six different methods in order to identify the correct orientation. The methods are first applied to a scan of dynamically simulated patterns, which is used to evaluate the sensitivity of the method to pattern resolution, pattern noise and pattern center error. It was determined that all six methods were 100% successful up to about 13 µm of pattern center error and pattern resolutions of about 80 × 80 pixels, and hence the methods were applied to an experimental sample of lamellar γ-TiAl. A hybrid combination of two of the methods was shown to successfully select the correct pseudosymmetry for about 96% of the points in the scan, improving upon the 70% accuracy of the Hough-based methods for the current study and 90% accuracy for previous studies resolving pseudosymmetry in lamellar γ-TiAl.

Pattern Center and Distortion Determined from Faint, Diffuse Electron Diffraction Rings from Amorphous Materials

Diffuse rings from amorphous materials sit on a steep background resulting in a monotonically decreasing intensity over scattering vector length, frequently with no clear local maximum that could be used to determine the center of the ring. The novelty of the method reported here is that it successful processes such weak patterns. It is based on separating the angular dependence of the positions of the maxima on the azimuthal angle in the measured two-dimensional pattern for a manually preselected peak. Both pattern center and elliptical distortion are simultaneously refined from this angular dependence. Both steps are based on nonlinear least square fitting, using the Levenberg–Marquardt method. It can be successfully applied to any amorphous patterns provided they were recorded with experimental conditions that facilitate dividing them into sectors with acceptable statistics. Patterns with the center shifted to the camera corner (recording a quadrant of a ring) can also be reliably evaluated, keeping precalibrated values of the elliptical distortion fixed during the fit. Finally, the limited number of counts in any pattern is overcome by cumulating many patterns (from equivalent areas) into a single pattern. Eliminating false effects is facilitated by masking out unwanted parts of any recorded pattern from processing.

Cloud Computing Application Pattern Library

On the basis of cloud computing introduction, the significance of cloud computing on library development is led out. It introduces several kinds of clouds applied in libraries at present—library carried on public cloud, library carried on private cloud and library carried on mixed cloud. It shows several patterns of cloud computing used in library—Internet carrying pattern, center-branch pattern and mixed pattern. Finally, the application pattern frame of library cloud computing is drawn up..

Estimation of the Full Nye Tensor by EBSD-Based Dislocation Microscopy

An extension to a previously published, novel stereological method is reported which infers experimentally inaccessible components of the Nye GND tensor. Limitations imposed by electron-opacity of metals prevent direct measurement of four components of the Nye tensor, but it is possible to use additional experimentally-obtainable information in connection with underlying field equilibrium equations to estimate these additional components. This approach uses derivatives to the infinitesimal elastic distortion tensor to reduce error imposed by pattern center inaccuracy.

Pattern Center Determination in Electron Backscatter Diffraction Microscopy

The pattern center of an electron backscatter diffraction (EBSD) image indicates the relative position of the image with reference to the interaction volume of the sample. As interest grows in high-resolution EBSD techniques, accurate knowledge of this position is essential for precise interpretation of the EBSD features. In a typical EBSD framework, Kikuchi bands are recorded on a phosphor screen. If the flat phosphor were instead shaped as a sphere, with its center at the specimen's electron interaction volume, then the incident backscattered electrons would form Kikuchi bands on that sphere with parallel band edges centered on great circles. In this article, the authors present a method of pattern center (PC) refinement that maps bands from the planar phosphor onto a virtual spherical screen and measures the deviation of bands from a great circle and from possessing parallel edges. Potential sources of noise and error, as well as methods for reducing these, are discussed. Finally, results are presented on the application of the PC algorithm to two types of simulated EBSD patterns and two experimental setups, and the resolution of the method is discussed.