scholarly journals Determination of the gravimetric factor at the Chandler period from Earth orientation data and superconducting gravimetry observations

1999 ◽  
Vol 136 (1) ◽  
pp. 1-7 ◽  
Author(s):  
S. Loyer ◽  
J. Hinderer ◽  
J.-P. Boy
Keyword(s):  
Orientation Data ◽  
Earth Orientation ◽  
Superconducting Gravimetry ◽  
Chandler Period

OrientXplot: a program to analyse and display relative crystal orientations

2015 ◽  
Vol 48 (4) ◽  
pp. 1330-1334 ◽  
Author(s):  
Ross Angel ◽  
Sula Milani ◽  
Matteo Alvaro ◽  
Fabrizio Nestola
Keyword(s):  
Single Crystals ◽  
Diffraction Pattern ◽  
Euler Angles ◽  
Electron Backscattered Diffraction ◽  
Orientation Data ◽  
User Control ◽  
Crystal Orientations ◽  
Orientation Matrix ◽  
Crystallographic Axes

Orientations of single crystals are usually determined by diffraction experiments. Indexing of a diffraction pattern from one crystal leads to the determination of its `orientation matrix', which defines the orientation of its crystallographic axes relative to a set of reference axes associated with the diffractometer. Crystal orientations can also be described in terms of Euler angles, especially from electron backscattered diffraction measurements.OrientXplotis a Windows program that reads all common types of orientation matrices, as well as orientation data such as Euler angles. The program calculates and displays the relative orientations of pairs of crystals, such as twins or inclusion crystals trapped inside host crystals.OrientXplotcan manipulate (under user control) the orientation matrices to allow for ambiguities in indexing that arise from crystal symmetries. Orientation data can be displayed on a stereogram or output in numerical form for plotting in external programs.

Determination of critical slip surface of fractured rock slopes based on fracture orientation data

2013 ◽  
Vol 56 (5) ◽  
pp. 1248-1256 ◽  
Author(s):  
Wen Zhang ◽  
JianPing Chen ◽  
Wu Zhang ◽  
Yan Lü ◽  
YuFei Ma ◽  
...  
Keyword(s):  
Slip Surface ◽  
Fractured Rock ◽  
Rock Slopes ◽  
Critical Slip Surface ◽  
Orientation Data ◽  
Fracture Orientation

Denoising of crystal orientation maps

2019 ◽  
Vol 52 (5) ◽  
pp. 984-996 ◽  
Author(s):  
R. Hielscher ◽  
C. B. Silbermann ◽  
E. Schmidl ◽  
Joern Ihlemann
Keyword(s):  
Variational Methods ◽  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Sliding Window ◽  
Orientation Data ◽  
Kernel Average Misorientation ◽  
Orientation Maps ◽  
Electron Backscatter ◽  
Backscatter Diffraction

This paper compares several well known sliding-window methods for denoising crystal orientation data with variational methods adapted from mathematical image analysis. The variational methods turn out to be much more powerful in terms of preserving low-angle grain boundaries and filling holes of non-indexed orientations. The effect of denoising on the determination of the kernel average misorientation and the geometrically necessary dislocation density is also discussed. Synthetic as well as experimental data are considered for this comparison. The examples demonstrate that variational denoising techniques are capable of significantly improving the accuracy of properties derived from electron backscatter diffraction maps.

Determination of the extragalactic-planetary frame tie from Earth orientation parameters

1997 ◽  
Vol 42 (4) ◽  
pp. 315-318
Author(s):  
Jinsong Ping ◽  
Jinling Li ◽  
Wenjing Jin ◽  
Zhihan Qian
Keyword(s):  
Earth Orientation Parameters ◽  
Earth Orientation ◽  
Orientation Parameters

Determination of Preferred Orientation in Crystals from Surface Diffraction Techniques

1971 ◽  
Vol 29 ◽  
pp. 186-187
Author(s):  
Isaac W. Diggs
Keyword(s):  
Electron Microscope ◽  
Angular Displacement ◽  
Preferred Orientation ◽  
Photographic Film ◽  
Orientation Data ◽  
Pattern Change ◽  
Diffraction Patterns ◽  
Nickel Crystals ◽  
Surface Diffraction

This paper will examine a method of determining preferred orientation in reflection diffraction specimen without the use of a camera constant for the electron microscope. This method was devised in the absence of being able to find any such method in the literature. The method was used to study the orientation of nickel crystals grown on the faces of Al2O3 substrates. The diffraction work was done with 75kv (.0446A) electrons on a model HU-11 Hitachi Electron Microscope. Diffraction patterns were recorded on a photographic film in such a manner that successive frames showed pattern change as a function of angular displacement (tilt rotation).If for any surface diffraction pattern, the orientation data of the crystals involved were desired, the following procedure would yield accurate results. The first action is to reproduce the pattern at a convenient size. This can be done by photographic means or by any other means available. Next, the interplanor spacings should be measured for at least three sets of planes which appear in the pattern.

scholarly journals Earth Orientation - The Current and Future Situation

1995 ◽  
Vol 166 ◽  
pp. 287-291
Author(s):  
Dennis D. McCarthy
Keyword(s):  
State Of The Art ◽  
International Earth Rotation Service ◽  
Earth Orientation Parameters ◽  
Earth Orientation ◽  
Current State ◽  
The Earth ◽  
Future Situation ◽  
Orientation Parameters

Sub-milliarcsecond astrometry often requires an accurate characterization of the orientation of the Earth in a quasi-inertial reference frame. The International Earth Rotation Service (IERS) standards provide the current state of the art in the transformation between celestial and terrestrial reference systems. Improvements in the determination of Earth orientation parameters which describe this transformation continue to be made. Current and future capabilities are given.

scholarly journals Earth Rotation in the Erold Framework

1981 ◽  
Vol 63 ◽  
pp. 41-51
Author(s):  
O. Calame
Keyword(s):  
Earth Rotation ◽  
Homogeneous Process ◽  
Partial Derivatives ◽  
Earth Orientation ◽  
New Generation

The project EROLD (Earth Rotation from Lunar Distances) was conceived in 1974, in the COSPAR framework, with the goal of demonstrating that the lunar distances technique might be an efficient candidate in a new-generation service for the determination of Earth orientation.Two years later, it was decided that the computations of the observational residuals and partial derivatives, as well as the analyses themselves, would be done at C.E.R.G.A. on a regular basis, for all the participating stations. Indeed, it was recognized to be important that all the observations be reduced in an homogeneous process. The target chosen for this program was that of Apollo XV which is the easiest to observe. Unfortunately, the operations could not start quickly due to a lack of observations and each station was encouraged to press the completion of the equipment, but many problems slowed the integration of these stations. Still now, only McDonald Observatory transmits observations regularly, and Orroral is operating, but with scattered results; presently this latter station is in course of modifications for improvement of accuracy.

scholarly journals Determination of the Long Period Nutation Terms from Optical Astrometry and VLBI Data

2000 ◽  
Vol 178 ◽  
pp. 607-612
Author(s):  
P. Yaya ◽  
C. Bizouard ◽  
C. Ron
Keyword(s):  
Linear Trend ◽  
Earth Orientation Parameters ◽  
Earth Orientation ◽  
Long Period ◽  
The Earth ◽  
Vlbi Data ◽  
Orientation Parameters

AbstractA 100-year long optical astrometric series of the Earth Orientation Parameters produced by a Czech team (Vondrák et al., 1998) has been analysed in order to determine components of nutation. Our interest is mostly focused on the long periodic terms: 18.6-year term, 9.3-year term and linear trend, still correlated in VLBI series which cover only the last 20 years. A comparison has been made with the corresponding values determined from the VLBI series.

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