scholarly journals Dark-field X-ray microscopy for multiscale structural characterization

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
H. Simons ◽  
A. King ◽  
W. Ludwig ◽  
C. Detlefs ◽  
W. Pantleon ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Structural Evolution ◽  
Physical And Mechanical Properties ◽  
Dark Field ◽  
Crystalline Materials ◽  
X Ray ◽  
Microscopy Technique ◽  
Three Dimensional Mapping ◽  
Macro Scale ◽  
Annealing Study

Abstract Many physical and mechanical properties of crystalline materials depend strongly on their internal structure, which is typically organized into grains and domains on several length scales. Here we present dark-field X-ray microscopy; a non-destructive microscopy technique for the three-dimensional mapping of orientations and stresses on lengths scales from 100 nm to 1 mm within embedded sampling volumes. The technique, which allows ‘zooming’ in and out in both direct and angular space, is demonstrated by an annealing study of plastically deformed aluminium. Facilitating the direct study of the interactions between crystalline elements is a key step towards the formulation and validation of multiscale models that account for the entire heterogeneity of a material. Furthermore, dark-field X-ray microscopy is well suited to applied topics, where the structural evolution of internal nanoscale elements (for example, positioned at interfaces) is crucial to the performance and lifetime of macro-scale devices and components thereof.

scholarly journals Retrieval of 3D information in X-ray dark-field imaging with a large field of view

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jana Andrejewski ◽  
Fabio De Marco ◽  
Konstantin Willer ◽  
Wolfgang Noichl ◽  
Theresa Urban ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dark Field ◽  
Large Field ◽  
X Ray ◽  
Dark Field Imaging ◽  
Beam Geometry ◽  
Different Dimensions ◽  
3D Information ◽  
Human Thorax ◽  
Field Imaging

AbstractX-ray dark-field imaging is a widely researched imaging technique, with many studies on samples of very different dimensions and at very different resolutions. However, retrieval of three-dimensional (3D) information for human thorax sized objects has not yet been demonstrated. We present a method, similar to classic tomography and tomosynthesis, to obtain 3D information in X-ray dark-field imaging. Here, the sample is moved through the divergent beam of a Talbot–Lau interferometer. Projections of features at different distances from the source seemingly move with different velocities over the detector, due to the cone beam geometry. The reconstruction of different focal planes exploits this effect. We imaged a chest phantom and were able to locate different features in the sample (e.g. the ribs, and two sample vials filled with water and air and placed in the phantom) to corresponding focal planes. Furthermore, we found that image quality and detectability of features is sufficient for image reconstruction with a dose of 68 μSv at an effective pixel size of $$0.357 \times {0.357}\,\mathrm{mm}^{2}$$ 0.357 × 0.357 mm 2 . Therefore, we successfully demonstrated that the presented method is able to retrieve 3D information in X-ray dark-field imaging.

scholarly journals The methods used for the diagnosis and evaluation of scoliosis

2016 ◽  
Vol 9 (17) ◽  
pp. 36-41 ◽  
Author(s):  
Ana-Maria Vutan ◽  
Erwin-Christian Lovasz ◽  
Mihaela Amarandei ◽  
Valentin Ciupe
Keyword(s):  
Three Dimensional ◽  
Growth Period ◽  
Small Scale ◽  
X Rays ◽  
Hematopoietic Tissue ◽  
X Ray ◽  
Advantages And Disadvantages ◽  
Non Invasive ◽  
Three Dimensional Mapping ◽  
Clinical Control

Abstract In recent years there multiple studies have been carried out on early diagnosis of scoliosis on school and preschool children. The diagnosis and evaluation of scoliosis is done by carrying out X-rays. A protocol is implemented for tracking the evolution of a scoliosis which involves both clinical control and imaging (X-ray) every 6 months, until the end of the growth period of the child. Because investigations such as X-ray and CT, can have harmful effects on the child's growing body (recent studies have shown that X-ray affects the skin, eyes, hematopoietic tissue, gonads and may cause cancer), new methods for diagnosing and tracking the evolution in time were researched. The present paper tries to present the current methods used in the diagnosis and assessment of scoliosis evolution in time, pointing out the main advantages and disadvantages of each method. There are a few methods developed in recent years in Germany by Zebris Medical Gmbh (using mapping with ultrasonic digital equipment), in Canada by InSpeck (using three-dimensional mapping through digital image acquisition) but used on a small scale. The newly developed methods have the advantage of being non-invasive, painless, non-irradiating and they can be used regardless of health status or gender. Although medical technology has developed very rapidly in recent years, radiology remains the most common method of investigation used for scoliosis. Certainly, in the near future the methods presented in this paper could be used more widely, for the benefits arising from their use.

scholarly journals Three-dimensional electron diffraction for porous crystalline materials: structural determination and beyond

2021 ◽  
Author(s):  
Zhehao Huang ◽  
Tom Willhammar ◽  
Xiaodong Zou
Keyword(s):  
Electron Diffraction ◽  
Three Dimensional ◽  
Structural Determination ◽  
New Materials ◽  
Dimensional Electron ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Structural Details

Three-dimensional electron diffraction is a powerful tool for accurate structure determination of zeolite, MOF, and COF crystals that are too small for X-ray diffraction. By revealing the structural details, the properties of the materials can be understood, and new materials and applications can be designed.

scholarly journals X-ray diffraction microscopy based on refractive optics

2017 ◽  
Vol 50 (5) ◽  
pp. 1441-1456 ◽  
Author(s):  
H. F. Poulsen ◽  
A. C. Jakobsen ◽  
H. Simons ◽  
S. R. Ahl ◽  
P. K. Cook ◽  
...  
Keyword(s):  
Axial Strain ◽  
Three Dimensional ◽  
Numerical Aperture ◽  
Dark Field ◽  
Reciprocal Space ◽  
Objective Lens ◽  
Optical Parameters ◽  
X Ray ◽  
Integrated Intensity ◽  
Dimensional Reconstruction

A formalism is presented for dark-field X-ray microscopy using refractive optics. The new technique can produce three-dimensional maps of lattice orientation and axial strain within millimetre-sized sampling volumes and is particularly suited toin situstudies of materials at hard X-ray energies. An objective lens in the diffracted beam magnifies the image and acts as a very efficient filter in reciprocal space, enabling the imaging of individual domains of interest with a resolution of 100 nm. Analytical expressions for optical parameters such as numerical aperture, vignetting, and the resolution in both direct and reciprocal spaces are provided. It is shown that the resolution function in reciprocal space can be highly anisotropic and varies as a function of position in the field of view. Inserting a square aperture in front of the objective lens facilitates disjunct and space-filling sampling, which is key for three-dimensional reconstruction and analysis procedures based on the conservation of integrated intensity. A procedure for strain scanning is presented. Finally the formalism is validated experimentally at an X-ray energy of 17 keV.

Three-dimensional mapping of nickel oxidation states using full field x-ray absorption near edge structure nanotomography

2011 ◽  
Vol 98 (17) ◽  
pp. 173109 ◽  
Author(s):  
George J. Nelson ◽  
William M. Harris ◽  
John R. Izzo ◽  
Kyle N. Grew ◽  
Wilson K. S. Chiu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Oxidation States ◽  
Edge Structure ◽  
Full Field ◽  
X Ray ◽  
Nickel Oxidation ◽  
Three Dimensional Mapping ◽  
X Ray Absorption ◽  
Dimensional Mapping

scholarly journals Multi-scale three-dimensional characterization with dark-field X-ray microscopy

2017 ◽  
Vol 73 (a2) ◽  
pp. C852-C852
Author(s):  
Hugh William Simons ◽  
Anders Clemen Jakobsen ◽  
Sonja Rosenlund Ahl ◽  
Phil Cook ◽  
Carsten Detlefs ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dark Field ◽  
X Ray ◽  
Multi Scale

Study of Micro Ultrasonic Machining of CFRP/Ti Stacks

2017 ◽  
Author(s):  
Abhishek Sonate ◽  
Dheeraj Vepuri ◽  
Sagil James
Keyword(s):  
Three Dimensional ◽  
Weight Ratio ◽  
Tool Material ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Groove Depth ◽  
Machining Process ◽  
Shear Stresses ◽  
Ultrasonic Machining ◽  
Macro Scale

Carbon fiber reinforced plastic (CFRP) composite is one of the most sought after material owing to its superior physical and mechanical properties such as high-durability and high strength-to-weight ratio. CFRP composites are often used by stacking up with titanium (Ti) to form multi-layered material stacks for applications involving extreme mechanical loads. However, machining of CFRP/Ti multi-stacks is quite complex and challenging task since both materials are difficult-to-machine materials and show completely different machinability properties. The challenge is further escalated when there is a need to machine CFRP/Ti stacks at micron level. Several problems arise during the machining process due to the non-homogeneous structure, anisotropic and abrasive properties of composite. Traditional methods of micromachining the CFRP/Ti stacks results in several issues including high cutting force and torque and high tool wear, composite delamination, large groove depth in composite, and poor surface quality. Ultrasonic machining (USM) process has been successfully used to machine titanium, CFRP and CFRP/Ti stack at macro scale. Micro Ultrasonic machining is a downsized version of macro ultrasonic machining process that is developed to machine hard and brittle materials. This research explores the possibility of using Micro USM process to conduct micromachining of CFRP/Ti multi stacks. The effect of various process parameters including abrasive grit size, tool material and type on the material removal process is studied. The study found that micro ultrasonic machining process is capable of successfully micromachining CFRP/Ti stacks with zero CFRP delamination, minimal variation in CFRP and Ti hole sizes and longer tool life. Further, a three-dimensional finite element simulation study is performed on micro ultrasonic machining of CFRP/Ti stacks. The simulation results revealed that the workpiece is not subject to any significant normal stresses during the machining process, while variations in shear stresses is seen on the inside surfaces of the machined cavities.

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