X-ray Tomography Study Research Articles

Fast X-ray tomography and acoustic emission study of damage in metals during continuous tensile tests

Model AA-2124 matrix composites with two different reinforcement sizes were pulled with a strain rate of 10 −5 using a dedicated tensile rig suitable for in situ tomography. Two main novelty aspects characterize the present study. First, tomography provides a new approach towards understanding the significance of AE signals, recorded simultaneously, during image acquisition on the same sample. The number of acoustic emission events is found to be in good agreement with the number of cracks as detected by image analysis and the energy of the signals is proportional to the dimension of the cracks. Secondly, fast tomography was used to perform the first continuous in situ tensile test. The continuous procedure is compared in the paper with the standard step by step procedure.

X-ray tomography study of the cellular structure of extruded starches and its relations with expansion phenomenon and foam mechanical properties

The cellular structure of extruded starch foams, with different amylose content (0–70%) has been determined by X-ray tomography (10 and 40 μm), leading to highly contrasted 3D images. These foam structures were analysed using a 3D granulometric approach. Their cellular features were determined for relative density ( D ∗) values in the interval [0.11, 0.34]. Their mean cell size (MCS) and mean cell wall thickness (MWT) varied in the range [0.2, 5 mm] and [75, 630 μm], respectively, and were strongly correlated. For the same value of D ∗, the finest structures (MCS < 2 mm and MWT < 300 μm) were found the most resistant to rupture. These finest cellular structures were mainly obtained for larger moisture content (24%) during extrusion. The influence of the extrusion variables on the phenomena occurring at die expansion, such as nucleation, bubble growth and coalescence, was discussed. Finally, the influence of amylose content was attributed to elongational viscosity, in relation with the storage modulus in the rubbery domain.

Neutron radiography as visualization and quantification method for conservation measures of wood firmness enhancement

Different oils, waxes, natural and synthetic resins are in use for conservation and stability enhancement of degraded wood samples. X-ray radiography, tomography and thermography studies were carried out at several places as an attempt for the visualization of the conservation procedures. Because of the high sensitivity of neutrons in detecting hydrogen-containing materials, the visualization of their distribution can be obtained by means of neutron radiography at the NEUTRA facility of SINQ with good resolution. One of the most common conservation preservatives for wood consolidation is the acryl resin “Paraloid B-72”. Combined with different solvents in a variety of solvent mixtures, B-72 can be used to address a diversity of absorption, dispersion or evaporation determinants for different wooden objects. Therefore, four different acryl resin solvents of the same acryl resin applied to coniferous wood samples (4×4×2.7 cm) were investigated to determine the uptake and loss processes, followed by measuring sequences of images of the 2-dimensional distribution. This was done by creating image sequences showing the process of uptake and loss processes as two-dimensional distribution over about 20 h. The resin uptake depends strongly on the solvent, as well on the proportion of the resin in the composition. The acryl-ethylacetate composition has the lowest uptake, but the composition of 20% acryl 80% toluol has soaked up almost eight times more. Out of these results, a composition of 20% acryl and 80% toluol seems to be the best of the tried compositions, because the greatest part of resin remains and its allocation seems to be the most homogeneous as well.

Characterization of new semiconductor detectors for x-ray tomography in the ASDEX Upgrade Tokamak and its generalized physics interpretations

The energy response of a new semiconductor detector in the ASDEX Upgrade Tokamak for plasma x-ray tomography studies is characterized using synchrotron radiation from a 2.5 GeV positron storage ring at the National Institute for High Energy Physics in Japan. This international collaborating research clarifies a fairly good agreement between the x-ray energy response data and our recently proposed theoretical predictions for such a semiconductor x-ray-detector response. The x-ray response for several positions on the active area of the detector unit is studied; a good uniformity observed guarantees that the detector can employ any sized and shaped collimator for the x-ray tomography regardless of any correction factor coming from the response nonuniformity on the detector active area. Operational conditions of the detector for the ASDEX Upgrade plasma diagnostics are optimized using its capacitance measurements as a function of an applied bias as well as the numerical evaluations of the detector response; these are also directly verified by the synchrotron-radiation experiments.

X-ray tomography studies of wellbore processes under in situ stress conditions

Wellbore processes such as invasion, mud/shale interaction, and rock failure around the wellbore, are of great importance in hydrocarbon exploitation. Experimental study of these phenomena is often carried out using model wellbores under appropriate stress and flow conditions, with observations of the wellbore wall or post-mortem examination of the interior of the rock.

The industrial X-ray tomography study of high resolution analyzers

The industrial X-ray tomography study of high resolution analyzers

The industrial X-ray tomography study of high resolution analyzers: 39628 Heut, J.; Pauton, M.; Thomas, G.; Casagrande, J.M.; Lagnier, P.; Glasser, F. Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13–17 Sep. 1987. Vol. 3, pp. 2133–2141. Pergamon Press, 3173 pp. (1988)

The industrial X-ray tomography study of high resolution analyzers: 39628 Heut, J.; Pauton, M.; Thomas, G.; Casagrande, J.M.; Lagnier, P.; Glasser, F. Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13–17 Sep. 1987. Vol. 3, pp. 2133–2141. Pergamon Press, 3173 pp. (1988)