Impact of sensor tilt on bio-inspired polarized skylight orientation determination

2021 ◽  
Vol 29 (5) ◽  
pp. 1024-1042
Author(s):  
Hua-ju LIANG ◽  
◽  
Hong-yang BAI ◽  
Tong ZHOU ◽  
Kai SHEN ◽  
...  
Keyword(s):  
Orientation Determination

Automatic analysis of Kikuchi diffraction patterns

1994 ◽  
Vol 52 ◽  
pp. 900-901
Author(s):  
H. Weiland ◽  
D. P. Field
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Spatial Resolution ◽  
Relevant Information ◽  
Crystalline Materials ◽  
Large Size ◽  
Transmission Electron ◽  
New Type ◽  
Diffraction Patterns ◽  
Orientation Determination

Recent advances in the automatic indexing of backscatter Kikuchi diffraction patterns on the scanning electron microscope (SEM) has resulted in the development of a new type of microscopy. The ability to obtain statistically relevant information on the spatial distribution of crystallite orientations is giving rise to new insight into polycrystalline microstructures and their relation to materials properties. A limitation of the technique in the SEM is that the spatial resolution of the measurement is restricted by the relatively large size of the electron beam in relation to various microstructural features. Typically the spatial resolution in the SEM is limited to about half a micron or greater. Heavily worked structures exhibit microstructural features much finer than this and require resolution on the order of nanometers for accurate characterization. Transmission electron microscope (TEM) techniques offer sufficient resolution to investigate heavily worked crystalline materials.Crystal lattice orientation determination from Kikuchi diffraction patterns in the TEM (Figure 1) requires knowledge of the relative positions of at least three non-parallel Kikuchi line pairs in relation to the crystallite and the electron beam.

Optimization of the FIB Preparation on Polycrystalline Al Materials through the Orientation Determination by EBSD

2019 ◽  
Vol 56 (1) ◽  
pp. 22-33
Author(s):  
U. Mühle ◽  
M. Löffler ◽  
T. Schubert ◽  
T. E. M. Staab ◽  
R. Krause-Rehberg ◽  
...  
Keyword(s):  
Orientation Determination

A statistical method for build orientation determination in additive manufacturing

2019 ◽  
Vol 25 (1) ◽  
pp. 187-207 ◽  
Author(s):  
Yicha Zhang ◽  
Ramy Harik ◽  
Georges Fadel ◽  
Alain Bernard
Keyword(s):  
Additive Manufacturing ◽  
Statistical Method ◽  
Supervised Machine Learning ◽  
Surface Model ◽  
Generic Level ◽  
Content Type ◽  
Build Orientation ◽  
Cad Models ◽  
Feature Based ◽  
Orientation Determination

Purpose For part models with complex shape features or freeform shapes, the existing build orientation determination methods may have issues, such as difficulty in defining features and costly computation. To deal with these issues, this paper aims to introduce a new statistical method to develop fast automatic decision support tools for additive manufacturing build orientation determination. Design/methodology/approach The proposed method applies a non-supervised machine learning method, K-Means Clustering with Davies–Bouldin Criterion cluster measuring, to rapidly decompose a surface model into facet clusters and efficiently generate a set of meaningful alternative build orientations. To evaluate alternative build orientations at a generic level, a statistical approach is defined. Findings A group of illustrative examples and comparative case studies are presented in the paper for method validation. The proposed method can help production engineers solve decision problems related to identifying an optimal build orientation for complex and freeform CAD models, especially models from the medical and aerospace application domains with much efficiency. Originality/value The proposed method avoids the limitations of traditional feature-based methods and pure computation-based methods. It provides engineers a new efficient decision-making tool to rapidly determine the optimal build orientation for complex and freeform CAD models.

Twin and topotactic growth of β-eucryptite dendrites and their lattice coincidence analysed by the reticular theory

2013 ◽  
Vol 46 (1) ◽  
pp. 216-223
Author(s):  
Shan-Rong Zhao ◽  
Hai-Jun Xu ◽  
Rong Liu ◽  
Qin-Yan Wang ◽  
Xian-Yu Liu
Keyword(s):  
Solid Solution ◽  
Crystallographic Orientation ◽  
Electron Backscatter Diffraction ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Backscatter Diffraction ◽  
Orientation Determination

Snowflake-shaped dendrites of β-eucryptite–β-quartz solid solution were artificially crystallized in a matt glaze, and the crystallographic orientation of the dendrites was analysed by the electron backscatter diffraction (EBSD) technique. The six branches of a snowflake-shaped dendrite in the plane (0001) are along 〈110〉. From the orientation determination, a twin relationship and a topotactic relationship between dendrites were found. The twin axes are [011], [0{\overline 1}1] and [210], and the twin planes perpendicular to the twin axes are ({\overline 1}2{\overline 1}2) and (1{\overline 2}12). From the reticular theory of twinning, it was calculated that the twin indexn= 2 and the obliquity ω = 3.2877°. The studied dendrite is a twin by reticular pseudomerohedry with low twin index and obliquity. In the topotactic growth, no twin elements have been found, but the three main crystallographic directions 〈001〉, 〈210〉 and 〈110〉 of the two dendritic crystals overlap each other. The degree of lattice coincidence between the two crystals in this topotactic growth is also discussed.

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