OCT-based three-dimensional strain mapping for elastography and relaxography

Author(s):  
Alexander A. Sovetsky ◽  
Alexander L. Matveyev ◽  
Ekaterina V. Gubarkova ◽  
Lev A. Matveev ◽  
Nadezhda P. Pavlova ◽  
...  
2022 ◽  
Vol 55 (1) ◽  
Author(s):  
Adam Lindkvist ◽  
Yubin Zhang

Laboratory diffraction contrast tomography (LabDCT) is a recently developed technique to map crystallographic orientations of polycrystalline samples in three dimensions non-destructively using a laboratory X-ray source. In this work, a new theoretical procedure, named LabXRS, expanding LabDCT to include mapping of the deviatoric strain tensors on the grain scale, is proposed and validated using simulated data. For the validation, the geometries investigated include a typical near-field LabDCT setup utilizing Laue focusing with equal source-to-sample and sample-to-detector distances of 14 mm, a magnified setup where the sample-to-detector distance is increased to 200 mm, a far-field Laue focusing setup where the source-to-sample distance is also increased to 200 mm, and a near-field setup with a source-to-sample distance of 200 mm. The strain resolution is found to be in the range of 1–5 × 10−4, depending on the geometry of the experiment. The effects of other experimental parameters, including pixel binning, number of projections and imaging noise, as well as microstructural parameters, including grain position, grain size and grain orientation, on the strain resolution are examined. The dependencies of these parameters, as well as the implications for practical experiments, are discussed.


1999 ◽  
Vol 39 (3) ◽  
pp. 217-226 ◽  
Author(s):  
B. K. Bay ◽  
T. S. Smith ◽  
D. P. Fyhrie ◽  
M. Saad

2018 ◽  
Vol 70 ◽  
pp. 260-269 ◽  
Author(s):  
Eng Kuan Moo ◽  
Scott C. Sibole ◽  
Sang Kuy Han ◽  
Walter Herzog

2019 ◽  
Vol 16 (160) ◽  
pp. 20190570 ◽  
Author(s):  
Arvin H. Soepriatna ◽  
A. Kevin Yeh ◽  
Abigail D. Clifford ◽  
Semih E. Bezci ◽  
Grace D. O'Connell ◽  
...  

Heart failure continues to be a common and deadly sequela of myocardial infarction (MI). Despite strong evidence suggesting the importance of myocardial mechanics in cardiac remodelling, many MI studies still rely on two-dimensional analyses to estimate global left ventricular (LV) function. Here, we integrated four-dimensional ultrasound with three-dimensional strain mapping to longitudinally characterize LV mechanics within and around infarcts in order to study the post-MI remodelling process. To induce infarcts with varying severities, we separated 15 mice into three equal-sized groups: (i) sham, (ii) 30 min ischaemia–reperfusion, and (iii) permanent ligation of the left coronary artery. Four-dimensional ultrasound from a high-frequency small animal system was used to monitor changes in LV geometry, function and strain over 28 days. We reconstructed three-dimensional myocardial strain maps and showed that strain profiles at the infarct border followed a sigmoidal behaviour. We also identified that mice with mild remodelling had significantly higher strains in the infarcted myocardium than those with severe injury. Finally, we developed a new approach to non-invasively estimate infarct size from strain maps, which correlated well with histological results. Taken together, the presented work provides a thorough approach to quantify regional strain, an important component when assessing post-MI remodelling.


2010 ◽  
Vol 652 ◽  
pp. 74-79 ◽  
Author(s):  
René V. Martins ◽  
Carsten Ohms ◽  
Koenraad Decroos

An 18 mm thick three-pass slot weld specimen in austenitic stainless steel, manufactured for the purpose of benchmarking Finite Element weld residual stress simulation codes, is currently undergoing extensive non-destructive characterization within a research network. First results from the non-destructive full three dimensional spatially resolved macro-strain mapping in this specimen are presented here. Focussed high-energy synchrotron radiation together with the spiral slit technique was used to obtain depth-resolved information about the variation of lattice parameters. The results show a strong concentration of tensile strain, transverse to the weld at mid-depth of the weld. The maximum longitudinal strains were observed beneath the weld. Furthermore significant weld start- and stop-effects were observed.


1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.


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