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415 results on '"di Michiel M"'

4. A comprehensive study of apatite grains in Ryugu rock fragments

Author

Tkalcec, B. J., primary, Tack, P., additional, De Pauw, E., additional, Bazi, B., additional, Vekemans, B., additional, Lindner, M., additional, Vincze, L., additional, Di Michiel, M., additional, Garrevoet, J., additional, Falkenberg, G., additional, Nakamura, T., additional, Morita, T., additional, Amano, K., additional, Nakashima, D., additional, Langenhorst, F., additional, Pollok, K., additional, Yurimoto, H., additional, Noguchi, T., additional, Okazaki, R., additional, Yabuta, H., additional, Naraoka, H., additional, Sakamoto, K., additional, Tachibana, S., additional, Yada, T., additional, Nishimura, M., additional, Nakato, A., additional, Miyazaki, A., additional, Yogata, K., additional, Abe, M., additional, Okada, T., additional, Usui, T., additional, Yoshikawa, M., additional, Saiki, T., additional, Tanaka, S., additional, Terui, F., additional, Nakazawa, S., additional, Watanabe, S., additional, Tsuda, Y., additional, and Brenker, F. E., additional

Published
2024
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5. Evidence for length-dependent wire expansion, filament dedensification and consequent degradation of critical current density in Ag-alloy sheathed Bi-2212 wires

Author

Malagoli, A, Lee, P J, Ghosh, A K, Scheuerlein, C, Di Michiel, M, Jiang, J, Trociewitz, U P, Hellstrom, E E, and Larbalestier, D C

Subjects
Condensed Matter - Superconductivity
Abstract

It is well known that longer Bi-2212 conductors have significantly lower critical current density (Jc) than shorter ones, and recently it has become clear that a major cause of this reduction is internal gas pressure generated during heat treatment, which expands the wire diameter and dedensifies the Bi-2212 filaments. Here we report on the length-dependent expansion of 5 to 240 cm lengths of state-of-the-art, commercial Ag alloy-sheathed Bi-2212 wire after full and some partial heat treatments. Detailed image analysis along the wire length shows that the wire diameter increases with distance from the ends, longer samples often showing evident damage and leaks provoked by the internal gas pressure. Comparison of heat treatments carried out just below the melting point and with the usual melt process makes it clear that melting is crucial to developing high internal pressure. The decay of Jc away from the ends is directly correlated to the local wire diameter increase, which decreases the local Bi-2212 filament mass density and lowers Jc, often by well over 50%. It is clear that control of the internal gas pressure is crucial to attaining the full Jc of these very promising round wires and that the very variable properties of Bi-2212 wires are due to the fact that this internal gas pressure has so far not been well controlled.

Published
2013
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6. Tetracarbonates in silicate melts may be at the origin of a deep carbon reservoir in the deep Earth

Author

Cerantola, V, Sahle, C, Petitgirard, S, Wu, M, Checchia, S, Weis, C, Di Michiel, M, Vaughan, G, Collings, I, Arató, R, Wilke, M, Jones, A, Hanfland, M, Tse, J, Cerantola V., Sahle C. J., Petitgirard S., Wu M., Checchia S., Weis C., Di Michiel M., Vaughan G. B. M., Collings I. E., Arató R., Wilke M., Jones A. P., Hanfland M., Tse J. S., Cerantola, V, Sahle, C, Petitgirard, S, Wu, M, Checchia, S, Weis, C, Di Michiel, M, Vaughan, G, Collings, I, Arató, R, Wilke, M, Jones, A, Hanfland, M, Tse, J, Cerantola V., Sahle C. J., Petitgirard S., Wu M., Checchia S., Weis C., Di Michiel M., Vaughan G. B. M., Collings I. E., Arató R., Wilke M., Jones A. P., Hanfland M., and Tse J. S.

Abstract

Much of Earth’s carbon may have been stripped away from the silicate mantle by dense metallic-iron during core formation. However, at deep magma ocean conditions carbon becomes less siderophile and thus large amounts of it may be stranded instead in the deep mantle. Here, we describe the structure and compaction mechanisms of carbonate glass to deep mantle pressures. Our results, based on non-resonant inelastic X-ray scattering, X-ray diffraction and ab initio calculations, demonstrate a pressure-induced change in hybridization of carbon from sp2 to sp3 starting at 40 GPa, due to the conversion of [3]CO32- groups into [4]CO44- units, which is completed at ~112 GPa. The pressure-induced change of carbon coordination number from three to four increases possibilities for carbon-oxygen interactions with lower mantle silicate melts. sp3 hybridized carbon provides a mechanism for changing the presumed siderophile nature of deep carbon, becoming a possible source for carbon-rich emissions registered at the surface in intra-plate and near-ridge hot spots.

Published
2023

19. Phase Contrast Imaging in the Field of Mammography

Author

Di Michiel, M., Olivo, A., Tromba, G., Arfelli, F., Bonvicini, V., Bravin, A., Cantatore, G., Castelli, E., Palma, L. Dalla, Longo, R., Pani, S., Pontoni, D., Poropat, P., Prest, M., Rashevsky, A., Vacchi, A., Vallazza, E., Ando, Masami, editor, and Uyama, Chikao, editor

Published
1998
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31. Deep denoising for multi-dimensional synchrotron X-ray tomography without high-quality reference data

Author

Hendriksen, A.A. (Allard), Bührer, M. (Minna), Leone, L. (Laura), Merlini, M. (Marco), Viganò, N.R. (Nicola), Pelt, D.M. (Daniël), Marone, F. (Federica), di Michiel, M. (Marco), Batenburg, K.J. (Joost), Hendriksen, A.A. (Allard), Bührer, M. (Minna), Leone, L. (Laura), Merlini, M. (Marco), Viganò, N.R. (Nicola), Pelt, D.M. (Daniël), Marone, F. (Federica), di Michiel, M. (Marco), and Batenburg, K.J. (Joost)

Abstract

Synchrotron X-ray tomography enables the examination of the internal structure of materials at submicron spatial resolution and subsecond temporal resolution. Unavoidable experimental constraints can impose dose and time limits on the measurements, introducing noise in the reconstructed images. Convolutional neural networks (CNNs) have emerged as a powerful tool to remove noise from reconstructed images. However, their training typically requires collecting a dataset of paired noisy and high-quality measurements, which is a major obstacle to their use in practice. To circumvent this problem, methods for CNN-based denoising have recently been proposed that require no separate training data beyond the already available noisy reconstructions. Among these, the Noise2Inverse method is specifically designed for tomography and related inverse problems. To date, applications of Noise2Inverse have only taken into account 2D spatial information. In this paper, we expand the application of Noise2Inverse in space, time, and spectrum-like domains. This development enhances applications to static and dynamic micro-tomography as well as X-ray diffraction tomography. Results on real-world datasets establish that Noise2Inverse is capable of accurate denoising and enables a substantial reduction in acquisition time while maintaining image quality.

Published
2021
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37. The digital mammography program at the SR light source in Trieste

Author

Arfelli, F., Barbiellini, G., Bonvicini, V., Bravin, A., Cantatore, G., Castelli, E., Dalla Palma, L., Di Michiel, M., Longo, R., Olivo, A., Pani, S., Pontoni, D., Poropat, P., Prest, M., Rashevsky, A., Tromba, G., and Vacchi, A.

Subjects
Mammography -- Equipment and supplies, Medical imaging equipment -- Innovations, Diagnostic imaging -- Digital techniques, Business, Electronics, Electronics and electrical industries
Abstract

A synchrotron radiation beamline devoted to medical imaging has been built by the SYRMEP collaboration at Elettra in Trieste, Italy, and is now in operation. The SYRMEP imaging system is based on the combination of a monochromatic, laminar X-ray beam, with a laminar, high-efficiency pixel silicon detector. To image soft tissue, including small, low-contrast details, as in mammography, beam energies should be chosen in the range from 15 keV to 30 keV and the detector should be capable of single-photon counting. The SYRMEP beamline originates from a bending magnet light port and consists basically of a Be window, a slit system and a Si(1,1,1) crystal monochromator. The experimental area is equipped with a radiation flux monitor, a sample movement stage, and a positioning system holding the silicon detector. Images are obtained by keeping the detector stationary with respect to the beam and by scanning the sample through the beam itself. The current detector is a linear array of 200x300 [[[micro]meter].sup.2] pixels, each coupled to its electronic counting chain on a custom VLSI read-out chip. We present a summary of beam studies, and digital images of standard RMI 160 and RMI 180 Ackermann Mammographic phantoms. Results show the high contrast resolution and the large dynamic range which constitute the defining characteristics of the SYRMEP imaging system.

Published
1997

38. An 'edge-on' silicon strip detector for X-ray imaging

Author

Arfelli, F., Barbiellini, G., Bonvicini, V., Bravin, A., Cantatore, G., Castelli, E., Di Michiel, M., Longo, R., Olivo, A., Pani, S., Pontoni, D., Poropat, P., Prest, M., Rashevsky, A., Tromba, G., and Vacchi, A.

Subjects
Silicon diodes -- Usage, X-rays -- Equipment and supplies, Diagnostic imaging -- Equipment and supplies, Business, Electronics, Electronics and electrical industries
Abstract

A silicon strip detector for the SYRMEP (SYncrotron Radiation for MEdical Physics) experiment has been designed and realised. The main features of this detector are AC-coupling through integrated coupling capacitors, DC biasing by means of a gated punch-through structure, bulk contact on the junction side through a forward-biased [p.sup.+] implant and integrated fan-in on active silicon. Results of laboratory tests of the detector parameters, allowing a thorough evaluation of the technological solutions employed, are presented. The functionality of the detectors and the charge collection linearity have been tested with different [Gamma] sources, using hybrid, low-noise front-end electronics.

Published
1997

39. Digital mammography at the Trieste Synchroton Light Source

Author

Arfelli, F., Barbiellini, G., Bonvicini, V., Bravin, A., Cantatore, G., Castelli, E., Dalla Palma, L., Di Michiel, M., Longo, R., Olivo, A., Pani, S., Pontoni, D., Poropat, P., Prest, M., Rosei, R., Sessa, M., Tromba, G., and Vacchi, A.

Subjects
Mammography -- Innovations, Image processing -- Digital techniques, Synchrotron radiation -- Usage, Silicon diodes -- Usage, Business, Electronics, Electronics and electrical industries
Abstract

The SYRMEP collaboration is developing a digital mammography project using a synchrotron radiation monochromatic X-ray beam and a silicon pixel detector. The combination of a monochromatic laminar beam with a high efficiency laminar detector, capable of single-photon counting, allows one to minimize the radiation dose delivered to the sample, while maximizing contrast resolution and dynamic range. The SYRMEP detector is a silicon microstrip device used in an innovative configuration in which radiation impinges on the side rather than on the surface of the chip and is therefore totally absorbed within the detector active volume. The high contrast resolution and spatial resolution (

Published
1996

42. Tracking internal temperature and structural dynamics during nail penetration of lithium-ion cells

Author

Finegan, D.P., Tjaden, B., Heenan, T.M.M., Jervis, R., Di Michiel, M., Rack, A., Hinds, G., Brett, D.J.L., and Shearing, P.R.

Subjects
PHASE CONTRAST, BATTERIES CHARGING, TIME-RESOLVED IMAGING, MICROTOMOGRAPHY, REAL TIME STUDIES
Abstract

Mechanical abuse of lithium-ion batteries is widely used during testing to induce thermal runaway, characterize associated risks, and expose cell and module vulnerabilities. However, the repeatability of puncture or ‘nail penetration’ tests is a key issue as there is often a high degree of variability in the resulting thermal runaway process. In this work, the failure mechanisms of 18650 cells punctured at different locations and orientations are characterized with respect to their internal structural degradation, and both their internal and surface temperature, all of which are monitored in real time. The initiation and propagation of thermal runaway is visualized via high-speed synchrotron X-ray radiography at 2000 frames per second, and the surface and internal temperatures are recorded via infrared imaging and a thermocouple embedded in the tip of the penetrating nail, respectively. The influence of the nail, as well as how and where it penetrates the cell, on the initiation and propagation of thermal runaway is described and the suitability of this test method for representing in-field failures is discussed.

Published
2017

44. Operando and Postreaction Diffraction Imaging of the La-Sr/CaO Catalyst in the Oxidative Coupling of Methane Reaction

Author

Matras, D., Jacques, S.D.M., Poulston, S., Grosjean, N., Estruch Bosch, C., Rollins, B., Wright, J., Di Michiel, M., Vamvakeros, A., Cernik, R.J., Beale, A.M., STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Johnson Matthey Technology Centre, and European Synchrotron Radiation Facility (ESRF)

Subjects
ResearchInstitutes_Networks_Beacons/dalton_nuclear_institute, FRELON CAMERA, CORDIERITE MONOLITHS, OXIDE, [CHIM]Chemical Sciences, Dalton Nuclear Institute
Abstract

A La-Sr/CaO catalyst was studied operando during the oxidative coupling of methane (OCM) reaction using the X-ray diffraction computed tomography technique. Full-pattern Rietveld analysis was performed in order to track the evolving solid-state chemistry during the temperature ramp, OCM reaction, as well as after cooling to room temperature. We observed a uniform distribution of the catalyst main components: La2O3, CaO-SrO mixed oxide, and the high-temperature rhombohedral polymorph of SrCO3. These were stable initially in the reaction; however, doubling the gas hourly space velocity resulted in the decomposition of SrCO3 to SrO, which subsequently led to the formation of a second CaO-SrO mixed oxide. These two mixed CaO-SrO oxides differed in terms of the extent of Sr incorporation into their unit cell. By applying Vegard's law during the Rietveld refinement, it was possible to create maps showing the spatial variation of Sr occupancy in the mixed CaO-SrO oxides. The formation of the Sr-doped CaO species is expected to have an important role in this system through the enhancement of the lattice oxygen diffusion as well as increased catalyst basicity.

Published
2019
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48. Interlaced X-ray diffraction computed tomography

Author

Vamvakeros, A., Jacques, S.D.M., Di Michiel, M., Senecal, P., Middelkoop, V., Cernik, R.J., and Beale, A.M.

Abstract

An X-ray diffraction computed tomography data-collection strategy that allows, post experiment, a choice between temporal and spatial resolution is reported. This strategy enables time-resolved studies on comparatively short timescales, or alternatively allows for improved spatial resolution if the system under study, or components within it, appear to be unchanging. The application of the method for studying an Mn-Na-W/SiO2 fixed-bed reactor in situ is demonstrated. Additionally, the opportunities to improve the data-collection strategy further, enabling post-collection tuning between statistical, temporal and spatial resolutions, are discussed. In principle, the interlaced scanning approach can also be applied to other pencil-beam tomographic techniques, like X-ray fluorescence computed tomography, X-ray absorption fine structure computed tomography, pair distribution function computed tomography and tomographic scanning transmission X-ray microscopy.

Published
2016

50. Ultrastable metallic glasses formed on cold substrates

Author

Luo, P., primary, Cao, C. R., additional, Zhu, F., additional, Lv, Y. M., additional, Liu, Y. H., additional, Wen, P., additional, Bai, H. Y., additional, Vaughan, G., additional, di Michiel, M., additional, Ruta, B., additional, and Wang, W. H., additional

Published
2018
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