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Wavelets — a new method for analysis of microstructure of composite materials
Published in Yasushi Miyano, Albert H. Cardon, Ken L. Reifsnider, Hiroshi Fukuda, Shinji Ogihara, Durability Analysis of Composite Systems 2001, 2020
The ability to make precise X-ray attenuation measurements on very small volume elements is known as X-ray microtomography to delineate the method as a form of X-ray microscopy that uses tomo-graphic reconstruction techniques to build three-dimensional images of microstructures. X-ray mi-crotomography is a relatively new technique that has not been applied to any significant extent in materials science [1-5]. Most X-ray microscopy development has so far been made using large synchrotron facilities. The use of X-ray tubes with a very small focus together with very sensitive recording devices enable the design of a bench-top X-ray microscope with a spatial resolution less than 8 sm. A common problem in morphological analysis of non-homogeneous materials is that three-dimensional information of microstructure is required, but its images are two-dimensional. Monitoring materials’ microstructure using X-ray microtomography allows us to begin to bridge this gap since a three-dimensional image of the specimen can be reconstructed from non-destructive, serial sections and can be processed to show and measure three-dimensional features.
Data Acquisition, Processing and Interpretation
Published in Peter E. J. Flewitt, Robert K. Wild, Physical Methods for Materials Characterisation, 2017
Peter E. J. Flewitt, Robert K. Wild
True 3-D images can be produced using incident sources such as X-rays, and then tomographic techniques are adopted to reconstruct the images. These approaches are based upon fundamental theory developed by Radon (1917). Although originally applied in the medical field, this technique has increasingly found wide applications for interrogating materials more generally. This has led to various considerations including microtomography (Sasov 1987, Cazaux 1993, Sasov and Van Dyke 1998). X-ray microtomography is an analytical technique which relies upon a mathematical algorithm to reconstruct a 3-D structure from 2-D X-ray images. Typically, the 3-D data are digitally rendered as 3-D visualisations using commercially available software (see Chapter 6). These software packages enable the data set for each specimen to be held in memory and visualised using a volume technique that can incorporate a lighting model and interactive real-time clipping. From these data, a wide range of image processing options are usually available (Lee 2013), for example volume estimates of void space within a material. The overall method of tomographic data processing can be applied to a range of signals acquired from synchrotron X-rays, electron transmission optical systems and, indeed, the pulsed field atom probe (Weyland and Midgley 2004, Aoyama et al. 2008, Loos et al. 2009, Danoix and Vurpillot 2012). As an example, Figure 7.21 shows an X-ray shadow image of a block of composite material, fibre-reinforced plastic foam. The reconstructed cross section (Figure 7.21b) reveals the periodic fibre structure, and Figure 7.21c provides more detail of the foam and fibre structure.
Microwave- and ultrasound-assisted convective drying of raspberries: Drying kinetics and microstructural changes
Published in Drying Technology, 2019
Justyna Szadzińska, Joanna Łechtańska, Reihaneh Pashminehazar, Abdolreza Kharaghani, Evangelos Tsotsas
One way of assessing the three-dimensional internal microstructure of dried food products is to use the X-ray microtomography technique. In the last 15 years, X-ray microtomography, originally developed for studies in the medical field, has found more and more applications in material science[28] and food engineering.[29,30] Contrary to other imaging techniques such as scanning electron microscopy, X-ray microcomputed tomography allows to study the microstructural changes of soft biological materials in nearly every condition (e.g., fresh, dried, or within preservatives). For example, X-ray computed tomography has been used to nondestructively follow the shrinkage and cracking of various porous materials during drying, such as coal,[31] banana,[32] chokeberries,[33] and sludge.[34]