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Articles de revues sur le sujet "X-Ray Micro-CT (Micro-Tomography)"
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Ishii, Keizo. « Micron X-ray computed tomography based on micro-particle-induced X-ray emission ». International Journal of PIXE 25, no 03n04 (janvier 2015) : 187–215. http://dx.doi.org/10.1142/s0129083515500175.
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Particle-induced X-ray emission (PIXE) is a phenomenon of atomic inner shell ionization and characteristic X-ray emission due to ion-atomic collisions. The intensity of continuous X-rays in the PIXE energy spectrum is much lower than that of characteristic X-rays. Therefore, PIXE can be used as a semi-monochromatic X-ray source. Furthermore, PIXE produced by a heavily charged particle beam with a diameter of several micrometers (micro-PIXE) can be used as a monochromatic X-ray point source for Xray computed tomography (CT) to investigate internal structures of objects <1 mm. We developed micron X-ray CT based on micro-PIXE with a spatial resolution of about 4 μm. Because the photoelectric effect cross-section is proportional to the fifth power of the atomic number, the distributions of small amounts of heavy elements can be investigated using this CT technique, and the element can be identified using its absorption edge. We applied this CT to observe the internal structure of hair, a head of an ant, and Drosophila. We were able to identify the medulla configuration and cortex of the hair, and the mandibular glands, pharynx, and brain in the ant head. We confirmed a high Mn concentration in the mandibular glands. We used a contrast agent to visualize the internal organs of Drosophila. Furthermore, we applied this CT to research clay particles contaminated by the Fukushima Dai-ichi nuclear accident and confirmed that cesium atoms were distributed on the surfaces of clay particles.
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Batranin, Andrey, Denis Ivashkov et Sergei Stuchebrov. « Performance Evaluation of Micro-CT Scanners as Visualization Systems ». Advanced Materials Research 1084 (janvier 2015) : 694–97. http://dx.doi.org/10.4028/www.scientific.net/amr.1084.694.
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High-resolution X-ray tomography, also known as micro-computed tomography (micro-CT) or microtomography, is a versatile evaluation technique, which extends application in various fields including material science. Micro-CT is a suitable method for quantitative and dimensional materials characterization. Needless to say, the accuracy of the method and applied equipments – micro-CT scanners – should be assessed to obtain reliable, solid results. In this paper, the performance of a micro-CT scanner as a visualization system is discussed. Quantitative parameters of image quality and visualization systems as well as methods to obtain their numerical values are briefly described. The results of experiments carried out on in-house made micro-CT scanner TOLMI-150-10 developed in Tomsk Polytechnic University are presented.
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Obenaus, André, et Anna Smith. « Radiation dose in rodent tissues during micro-CT imaging ». Journal of X-Ray Science and Technology : Clinical Applications of Diagnosis and Therapeutics 12, no 4 (janvier 2004) : 241–49. http://dx.doi.org/10.3233/xst-2004-00116.
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The use of non-invasive imaging modalities, including micro X-ray computed tomography (micro-CT), is starting to be used extensively to investigate normal and pathological states in a variety of animal models. This increased use of in vivo imaging requires a better understanding of the radiation dose delivered during routine imaging. Our laboratory is equipped with a micro X-ray computer tomography unit (MicroCAT II®, ImTek Inc., Knoxville, TN) with a 60 kVp X-ray source and a reconstruction volume resolution as low as 15 microns that is used for proton radiation therapy treatment planning. In order to determine the X-ray radiation dose delivered to skin and internal organs by our micro-CT we implanted new, calibrated Harshaw TLD-100 Lithium Fluoride thermo-luminescent detectors (TLDs), into five C57BL/6 male mice and ten Sprague-Dawley male rats. Implants were made into the brain, heart, right lung, liver, stomach, cecum, bladder, dorsal thoracal skin and ventral abdominal skin in each animal. Animals were each scanned once using 50 kVp at 800 μA with 360 projections per scan with each projection lasting 400 msec. Using the TLD readings, the radiation dose from each body location was measured with the dorsal thoracal skin receiving the highest average dose (4.5 cGy, mouse; 2.8 cGy, rat) and other internal organs receiving significantly lower average doses. Therefore, knowing the radiation doses delivered during routine imaging, care can be taken to avoid significant and potentially lethal doses of radiation.
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Jones, Julian R., Georgina E. Milroy, Ruth Cameron, William Bonfield et Larry L. Hench. « Using X-Ray Micro-CT Imaging to Monitor Dissolution of Macroporous Bioactive Glass Scaffolds ». Key Engineering Materials 284-286 (avril 2005) : 493–96. http://dx.doi.org/10.4028/www.scientific.net/kem.284-286.493.
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Bioactive glass scaffolds with interconnected macroporous networks have been developed by foaming sol-gel derived bioactive glass of the 70S30C (70 mol% SiO2, 30 mol% CaO) composition. The effect of sintering temperature on the dissolution of the scaffolds in simulated body fluid (SBF) was investigated in 3D using x-ray micro-computer tomography (micro CT) and inductive coupled plasma (ICP) analysis. Micro-CT is non-destructive and allows observation of specific parts of the scaffold at various stages of degradation. However, data analysis is complex at present. Percentage porosity data obtained by micro-CT was compared to physical data and pore size distributions obtained from mercury intrusion porosimetry were compared to the interconnected pore diameters observed from the micro CT images.
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Dimonie, Doina, Ionut-Cristian Radu, George Vlasceanu, Catalin Zaharia, Nicoleta Dragomir, Ovidiu Dima et Sorina Iftimie. « Estimating the 3D Printing Defects by Micro-Computed Tomography ». Proceedings 57, no 1 (18 novembre 2020) : 97. http://dx.doi.org/10.3390/proceedings2020057097.
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Litzlbauer, Horst Detlef, Christoph Neuhaeuser, Alexander Moell, Susanne Greschus, Andreas Breithecker, Folker Ernst Franke, Wolfgang Kummer et Wigbert Stephan Rau. « Three-dimensional imaging and morphometric analysis of alveolar tissue from microfocal X-ray-computed tomography ». American Journal of Physiology-Lung Cellular and Molecular Physiology 291, no 3 (septembre 2006) : L535—L545. http://dx.doi.org/10.1152/ajplung.00088.2005.
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We evaluated microfocal X-ray-computed tomography (micro-CT) as a method to visualize lung architecture two and three dimensionally and to obtain morphometric data. Inflated porcine lungs were fixed by formaldehyde ventilation. Tissue samples (8-mm diameter, 10-mm height) were stained with osmium tetroxide, and 400 projection images (1,024 × 1,024 pixel) were obtained. Continuous isometric micro-CT scans (voxel size 9 μm) were acquired to reconstruct two- and three-dimensional images. Tissue samples were sectioned (8-μm thickness) for histological analysis. Alveolar surface density and mean linear intercept were assessed by stereology-based morphometry in micro-CT scans and corresponding histological sections. Furthermore, stereology-based morphometry was compared with morphometric semi-automated micro-CT analysis within the same micro-CT scan. Agreement of methods was assessed by regression and Bland-Altman analysis. Comparing histology with micro-CT, alveolar surface densities (35.4 ± 2.4 vs. 33.4 ± 1.9/mm, P < 0.05) showed a correlation ( r = 0.72; P = 0.018) with an agreement of 2 ± 1.6/mm; the mean linear intercept (135.7 ± 14.5 vs. 135.8 ± 15 μm) correlated well ( r = 0.97; P < 0.0001) with an agreement of −0.1 ± 3.4 μm. Semi-automated micro-CT analysis resulted in smaller alveolar surface densities (33.4 ± 1.9 vs. 30.5 ± 1/mm; P < 0.01) with a correlation ( r = 0.70; P = 0.023) and agreement of 2.9 ± 1.4/mm. Non-destructive micro-CT scanning offers the advantage to visualize the spatial tissue architecture of small lung samples two and three dimensionally.
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Zou, Shuo, Serena Best et William Bonfield. « Segementation of X-Ray Microtomography Data of Porous Scaffold ». Key Engineering Materials 330-332 (février 2007) : 911–14. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.911.
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Computerized X-ray micro tomography (micro CT) is a powerful technique for studying the structure and properties of porous scaffold. A variety of sample parameters can be studied using a single micro CT scan [1]. In general a segmented data set is a required for most quantitative analysis. However, segmentation of CT data can be difficult due to the artifacts in micro CT images such as blurred interfaces due to the machine contrast transfer function and the partial volume effect. Therefore the segmentation can be biased and prone to errors. Many methods have been developed to improve segmentation, however the interface problem has not been solved perfectly [2]. Porous scaffolds suffer from these effects because of their high surface to volume ratio and hence large interface. In this paper we discuss the interface problem in detail and demonstrate the effect of voxel size on the histograms of CT images of porous scaffold as well as a thresholding method based on 2 dimensional histogram is also presented. The potential of this method in more complicated scenarios such as 3-phase system is currently being investigated [3].
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Barburski, Marcin, Ilya Straumit et Stepan V. Lomov. « Internal Structure of the Sheared Textile Composite Reinforcement : Analysis Using X-Ray Tomography ». Key Engineering Materials 651-653 (juillet 2015) : 325–30. http://dx.doi.org/10.4028/www.scientific.net/kem.651-653.325.
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X-ray micro computed tomography (Micro-CT) is a non-destructive technique that can provide information on the internal structure of materials. The purpose of micro-CT is to assess the presence of defects as well as characterizing internal structures and potential damage present in the produced part. Simple shear is an interesting deformation mechanism for woven fabric draping. The internal structure change of the carbon fibre twill fabric after shear deformation is chosen as a subject of this paper. Parameters of the mesoscopic internal structure of the woven fabric like cross section, shape, area, and middle line coordinates can be obtained from micro-CT images through image processing procedures. Details of the image data processing for sheared fabric cross sections are discussed. This paper illustrates the possibilities of micro-focus computer tomography in materials research, namely for defining geometrical properties of textile. Image processing is also used for the recognition of fibre direction in the yarns. Described methodology can be applied for determining structure of a fabric, and the results can be used for further micromechanical modelling. Identification of the fibres orientation is important for estimation of the mechanical properties of composites and can be achieved with image processing techniques.
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Heyn, René, Abraham Rozendaal, Anton Du Plessis et Carene Mouton. « Characterization of Coloured Gemstones by X-ray Micro Computed Tomography ». Minerals 11, no 2 (8 février 2021) : 178. http://dx.doi.org/10.3390/min11020178.
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The monetary value of gemstones is based on five variables: rarity, cut, weight, color and clarity. The latter refers to internal impurities and defects. Fashion may also dictate demand and price. To enhance some of these features and value, gemstones are treated. Disclosure or nondisclosure thereof has been controversial and affected consumer confidence. Most of these treatments are difficult to detect with the naked eye and accurately quantify with traditional optical and analytical methods. X-ray micro computed tomography (micro-CT or μCT) is proposed as a relatively low cost, physically non-destructive and complementary method to detect and quantify clarity enhancement and also to provide a unique 3D fingerprint of each gemstone. A collection of 14 cut colored gemstones was selected. Micro-CT scans allowed fracture detection, their distribution and calculation of filler volume as well as 3D mapping of inclusions, surface and internal imperfections and artificially induced modifications. As a result the method allows the construction of a digital twin. X-ray exposure could however induce unwanted color changes. This effect was minimized or eliminated by optimizing dosage and exposure time.
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Rashidi, Armin, Tina Olfatbakhsh, Bryn Crawford et Abbas S. Milani. « A Review of Current Challenges and Case Study toward Optimizing Micro-Computed X-Ray Tomography of Carbon Fabric Composites ». Materials 13, no 16 (14 août 2020) : 3606. http://dx.doi.org/10.3390/ma13163606.
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X-ray computed tomography provides qualitative and quantitative structural and compositional information for a broad range of materials. Yet, its contribution to the field of advanced composites such as carbon fiber reinforced polymers is still limited by factors such as low imaging contrast, due to scarce X-ray attenuation features. This article, through a review of the state of the art, followed by an example case study on Micro-computed tomography (CT) analysis of low X-ray absorptive dry and prepreg carbon woven fabric composites, aims to highlight and address some challenges as well as best practices on performing scans that can capture key features of the material. In the case study, utilizing an Xradia Micro-CT-400, important aspects such as obtaining sufficient contrast, an examination of thin samples, sample size/resolution issues, and image-based modeling are discussed. The outcome of an optimized workflow in Micro-CT of composite fabrics can assist in further research efforts such as the generation of surface or volume meshes for the numerical modeling of underlying deformation mechanisms during their manufacturing processes.
Thèses sur le sujet "X-Ray Micro-CT (Micro-Tomography)"
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Sen, Sharma Kriti. « Compressed Sensing based Micro-CT Methods and Applications ». Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/52866.
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High-resolution micro computed tomography (micro-CT) offers 3D image resolution of 1 um for non-destructive evaluation of various samples. However, the micro-CT performance is limited by several factors. Primarily, scan time is extremely long, and sample dimension is restricted by the x-ray beam and the detector size. The latter is the cause for the well-known interior problem. Recent advancement in image reconstruction, spurred by the advent of compressed sensing (CS) theory in 2006 and interior tomography theory since 2007, offers great reduction in the number of views and an increment in the volume of samples, while maintaining reconstruction accuracy. Yet, for a number of reasons, traditional filtered back-projection based reconstruction methods remain the de facto standard on all manufactured scanners.
This work demonstrates that CS based global and interior reconstruction methods can enhance the imaging capability of micro-CT scanners. First, CS based few-view reconstruction methods have been developed for use with data from a real micro-CT scanner. By achieving high quality few-view reconstruction, the new approach is able to reduce micro-CT scan time to up to 1/8th of the time required by the conventional protocol. Next, two new reconstruction techniques have been developed that allow accurate interior reconstruction using just a limited number of global scout views as additional information. The techniques represent a significant progress relative to the previous methods that assume a fully sampled global scan. Of the two methods, the second method uses CS techniques and does not place any restrictions on scanning geometry. Finally, analytic and iterative reconstruction methods have been developed for enlargement of the field of view for the interior scan with a small detector. The idea is that truncated projections are acquired in an offset detector geometry, and the reconstruction procedure is performed through the use of a weighting function / weighted iteration updates, and projection completion. The CS based reconstruction yields the highest image quality in the numerical simulation. Yet, some limitations of the CS based techniques are observed in case of real data with various imperfect properties. In all the studies, physical micro-CT phantoms have been designed and utilized for performance analysis. Also, important guidelines are suggested for future improvements.Ph. D.
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PARISATTO, MATTEO. « APPLICATIONS OF X-RAY TOMOGRAPHIC TECHNIQUES TO THE STUDY OF CEMENT-BASED MATERIALS ». Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3421653.
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The knowledge of the microstructural properties of cement-based materials plays a fundamental role in predicting their macroscopic behaviour in terms of performance and durability. However, due to the intrinsic microstructural and chemical complexity of such materials, a multi-disciplinary approach is often required. Most classical experimental techniques such as XRD, XRF or mercury porosimetry (MIP) only provide overall information about selected properties (phase and chemical composition, porosity, etc.) but give no indications about their real spatial distribution within the investigated sample. Over the past decades, modern experimental methods for microstructural analysis such as SEM imaging have lead to great advances in our understanding of the complex mechanisms occurring during cement hydration. However, the lack of access to three-dimensional (3D) information represents the main limitation of SEM and other 2D imaging techniques. Furthermore, as sample preparation is often quite invasive, the microstructure of cement may result completely altered. For such reasons, the development of non-destructive techniques for the 3D microstructural investigation of materials has become necessary. Nowadays X-ray computed micro-tomography (X-μCT) provides a totally non-invasive tool to investigate in a three-dimensional way the inner structure of materials, with a spatial resolution reaching the sub-μm level when the most advanced systems are employed. X-μCT allows to reconstruct 3D maps of the variations of the X-ray linear attenuation coefficient (μ) within a sample without perturbing its structure.
The aim of this research project is to assess the potential of X-μCT for the microstructural study of several features of interest in cementitious materials. The evolution of the microstructure during setting and hardening, the effects of water-cement ratio (w/c), the role of superplasticizers and the pore space properties are among the major topics that have been investigated. The results obtained from X-μCT at the microscopic scale can then be correlated with the corresponding macroscopic properties observed in real applications.
In order to compare the capabilities of the two most common types of X-μCT setups, experiments were carried out using both conventional laboratory instruments and synchrotron-based systems. A synchrotron study of cement evolution during the early hydration stages was successfully performed, focusing the attention on the effect of superplasticizers (chapter 4). The high spatial resolution achievable allowed to follow the evolution of porosity and anhydrous cement fraction as a function of hydration time. In chapter 5, conventional laboratory X-μCT was applied to the study of cement paste samples prepared at different w/c ratios in order to get insights on the microstructural features that determine the variations of strengths in macroscopic samples with varying water contents (chapter 5).
In addition, the capabilities of a novel experimental technique (diffraction tomography, XRD-CT) were tested for the first time on cementitious samples (chapter 6). By combining the principles of X-ray micro-diffraction with those of tomographic reconstruction, XRD-CT allows to map the distribution of selected crystalline or amorphous phases within a sample in a totally non invasive manner. In this way, one of the main limitations of X-μCT, related to the poor sensitivity to small absorption variations between different phases can be overcome. Despite the fact that data analysis is not straightforward and requires further developments, the preliminary results presented in this thesis show that crystalline and amorphous phases growing during cement hydration such as ettringite and C-S-H can be successfully mapped without perturbing the system.
In the last part of the thesis (chapter 7), a practical application example of X-μCT is reported. The tomographic technique was employed to characterize the pore space properties and the microstructure of cementitious granular materials produced from the solidification and stabilization process (S/S) of soils contaminated by heavy metals. The results of X-μCT analyses were then combined with those obtained using other established experimental methods (e.g. MIP, physico-mechanical and leaching tests) in order to evaluate the performances and environmental compatibility of an innovative method of contaminated grounds remediation.La conoscenza delle proprietà microstrutturali dei materiali cementizi gioca un ruolo fondamentale nel predire il loro comportamento macroscopico in termini di prestazioni e durabilità. Tuttavia, a causa dell’intrinseca complessità microstrutturale e chimica di tali materiali, un approccio multi disciplinare è spesso richiesto. La maggior parte delle tecniche sperimentali classiche come XRD, XRF o la porosimetria a mercurio (MIP) forniscono solamente informazioni complessive riguardo determinate proprietà (composizione mineralogica e chimica, porosità, etc.) ma non danno alcuna indicazione sulla loro reale distribuzione spaziale all’interno del campione studiato. Nel corso degli ultimi decenni, i moderni metodi sperimentali per l’analisi microstrutturale come la microscopia elettronica a scansione (SEM) hanno portato ad importanti avanzamenti delle nostre conoscenze sui complessi meccanismi che avvengono nel corso dell’idratazione del cemento. Tuttavia, l’impossibilità di accedere ad informazioni tridimensionali (3D) rappresenta la principale limitazione della tecnica SEM e degli altri metodi di imaging 2D. Inoltre, poiché la preparazione del campione è spesso piuttosto invasiva, la microstruttura del cemento può risultare completamente alterata. Per tali ragioni, si è reso necessario lo sviluppo di tecniche non distruttive per lo studio microstrutturale in 3D dei materiali. Oggigiorno, la micro-tomografia computerizzata a raggi X (X-μCT) fornisce uno strumento totalmente non invasivo per studiare in modo tridimensionale la struttura interna dei materiali, con una risoluzione spaziale che può raggiungere il livello sub-micrometrico quando vengono utilizzati i sistemi più avanzati. La X-μCT consente di ricostruire mappe in 3D delle variazioni del coefficiente di attenuazione lineare dei raggi X (μ) all’interno di un campione senza perturbarne la struttura. Lo scopo di questo progetto di ricerca è quello di verificare le potenzialità della X-μCT per lo studio microstrutturale di diversi aspetti di interesse nei materiali cementizi. Tra le principali tematiche che sono state affrontate vi sono l’evoluzione della microstruttura durante la presa e l’indurimento, gli effetti del rapporto acqua-cemento, il ruolo degli additivi superfluidificanti e le proprietà dello spazio poroso. I risultati ottenuti dalla X-μCT alla scala microscopica possono essere correlati con le corrispondenti proprietà microscopiche osservate nelle applicazioni reali. Al fine di confrontare le potenzialità delle due principali tipologie di strumenti per X-μCT, sono stati effettuati esperimenti utilizzando sia sistemi convenzionali da laboratorio sia sistemi da sincrotrone. Uno studio al sincrotrone sull’evoluzione del cemento nel corso degli stadi iniziali dell’idratazione è stato portato a termine con successo, ponendo l’attenzione sull’effetto dei superfluidificanti (cap. 4). L’elevata risoluzione spaziale ottenibile ha consentito di seguire l’evoluzione della porosità e della frazione di cemento anidro in funzione del tempo di idratazione. Nel capitolo 5, la X-μCT convenzionale da laboratorio è stata applicata allo studio di campioni di paste di cemento preparati a diverso rapporto acqua-cemento al fine di ottenere indicazioni sui parametri microstrutturali che determinano le variazioni delle resistenze meccaniche in campioni macroscopici al variare del contenuto d’acqua. Inoltre, le potenzialità di una tecnica sperimentale recentemente sviluppata (diffraction tomography, XRD-CT) sono state testate per la prima volta su campioni cementizi (cap. 6). La tecnica della XRD-CT, combinando i principi della micro-diffrazione a raggi X con quelli della ricostruzione tomografica, consente di mappare la distribuzione di determinate fasi cristalline o amorfe all’interno di un campione in una maniera del tutto non invasiva. In questo modo, una delle principali limitazioni della X-μCT legata alla scarsa sensibilità nei confronti di ridotte variazioni di assorbimento tra diverse fasi può essere superata. Nonostante l’analisi dei dati non sia semplice e richieda ulteriori sviluppi, i risultati preliminari presentati in questa tesi mostrano che alcune fasi, sia cristalline sia amorfe, che si sviluppano nel corso dell’idratazione del cemento (come ad esempio l’ettringite o il C-S-H), possono essere mappate con successo senza perturbare il sistema. Nell’ultima parte del lavoro è riportato un esempio pratico di applicazione della X-μCT. La tecnica tomografica è stata utilizzata per caratterizzare la porosità e la microstruttura di materiali cementizi granulari prodotti dal processo di solidificazione e stabilizzazione (S/S) di suoli contaminati da metalli pesanti. I risultati delle analisi di X-μCT sono stati poi combinati con quelli ottenuti usando altri metodi sperimentali classici (ad esempio MIP, test fisico-meccanici e di cessione) al fine di valutare le prestazioni e la compatibilità ambientale di un metodo innovativo di bonifica dei terreni inquinati.
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Baumann, Michael. « Performance of a Micro-CT System : Characterisation of Hamamatsu X-ray source L10951-04 and flat panel C7942CA-22 ». Thesis, KTH, Skolan för teknik och hälsa (STH), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-155454.
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This master thesis evaluated the performance of a micro-CT system consisting of Hamamatsu microfocus X-ray source L10951-04 and CMOS flat panel C7942CA-22. The X-ray source and flat panel have been characterised in terms of dark current, image noise and beam profile. Additionally, the micro-CT system’s spatial resolution, detector lag and detector X-ray response have been measured. Guidance for full image correction and methods for characterisation and performance test of the X-ray source and detector is presented. A spatial resolution of 7 lp/mm at 10 % MTF was measured. A detector lag of 0.3 % was observed after ten minutes of radiation exposure. The performance of the micro-CT system was found to be sufficient for high resolution X-ray imaging. However, the detector lag effect is strong enough to reduce image quality during subsequent image acquisition and must either be avoided or corrected for.
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Weber, Loriane. « Iterative tomographic X-Ray phase reconstruction ». Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI085/document.
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L’imagerie par contraste de phase suscite un intérêt croissant dans le domaine biomédical, puisqu’il offre un contraste amélioré par rapport à l’imagerie d’atténuation conventionnelle. En effet, le décalage en phase induit par les tissus mous, dans la gamme d’énergie utilisée en imagerie, est environ mille fois plus important que leur atténuation. Le contraste de phase peut être obtenu, entre autres, en laissant un faisceau de rayons X cohérent se propager librement après avoir traversé un échantillon. Dans ce cas, les signaux obtenus peuvent être modélisés par la diffraction de Fresnel. Le défi de l’imagerie de phase quantitative est de retrouver l’atténuation et l’information de phase de l’objet observé, à partir des motifs diffractés enregistrés à une ou plusieurs distances. Ces deux quantités d’atténuation et de phase, sont entremêlées de manière non-linéaire dans le signal acquis. Dans ces travaux, nous considérons les développements et les applications de la micro- et nanotomographie de phase. D’abord, nous nous sommes intéressés à la reconstruction quantitative de biomatériaux à partir d’une acquisition multi-distance. L’estimation de la phase a été effectuée via une approche mixte, basée sur la linéarisation du modèle de contraste. Elle a été suivie d’une étape de reconstruction tomographique. Nous avons automatisé le processus de reconstruction de phase, permettant ainsi l’analyse d’un grand nombre d’échantillons. Cette méthode a été utilisée pour étudier l’influence de différentes cellules osseuses sur la croissance de l’os. Ensuite, des échantillons d’os humains ont été observés en nanotomographie de phase. Nous avons montré le potentiel d’une telle technique sur l’observation et l’analyse du réseau lacuno-canaliculaire de l’os. Nous avons appliqué des outils existants pour caractériser de manière plus approfondie la minéralisation et les l’orientation des fibres de collagènes de certains échantillons. L’estimation de phase, est, néanmoins, un problème inverse mal posé. Il n’existe pas de méthode de reconstruction générale. Les méthodes existantes sont soit sensibles au bruit basse fréquence, soit exigent des conditions strictes sur l’objet observé. Ainsi, nous considérons le problème inverse joint, qui combine l’estimation de phase et la reconstruction tomographique en une seule étape. Nous avons proposé des algorithmes itératifs innovants qui couplent ces deux étapes dans une seule boucle régularisée. Nous avons considéré un modèle de contraste linéarisé, couplé à un algorithme algébrique de reconstruction tomographique. Ces algorithmes sont testés sur des données simuléesPhase contrast imaging has been of growing interest in the biomedical field, since it provides an enhanced contrast compared to attenuation-based imaging. Actually, the phase shift of the incoming X-ray beam induced by an object can be up to three orders of magnitude higher than its attenuation, particularly for soft tissues in the imaging energy range. Phase contrast can be, among others existing techniques, achieved by letting a coherent X-ray beam freely propagate after the sample. In this case, the obtained and recorded signals can be modeled as Fresnel diffraction patterns. The challenge of quantitative phase imaging is to retrieve, from these diffraction patterns, both the attenuation and the phase information of the imaged object, quantities that are non-linearly entangled in the recorded signal. In this work we consider developments and applications of X-ray phase micro and nano-CT. First, we investigated the reconstruction of seeded bone scaffolds using sed multiple distance phase acquisitions. Phase retrieval is here performed using the mixed approach, based on a linearization of the contrast model, and followed by filtered-back projection. We implemented an automatic version of the phase reconstruction process, to allow for the reconstruction of large sets of samples. The method was applied to bone scaffold data in order to study the influence of different bone cells cultures on bone formation. Then, human bone samples were imaged using phase nano-CT, and the potential of phase nano-imaging to analyze the morphology of the lacuno-canalicular network is shown. We applied existing tools to further characterize the mineralization and the collagen orientation of these samples. Phase retrieval, however, is an ill-posed inverse problem. A general reconstruction method does not exist. Existing methods are either sensitive to low frequency noise, or put stringent requirements on the imaged object. Therefore, we considered the joint inverse problem of combining both phase retrieval and tomographic reconstruction. We proposed an innovative algorithm for this problem, which combines phase retrieval and tomographic reconstruction into a single iterative regularized loop, where a linear phase contrast model is coupled with an algebraic tomographic reconstruction algorithm. This algorithm is applied to numerical simulated data
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Sencu, Razvan. « Multiscale stochastic fracture mechanics of composites informed by in-situ X-ray CT tests ». Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/multiscale-stochastic-fracture-mechanics-of-composites-informed-by-insitu-xray-ct-tests(85a0be40-9e7a-4df3-a366-69ac6ce02e35).html.
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This thesis presents the development of a new multiscale stochastic fracture mechanics modelling framework informed by in-situ X-ray Computed Tomography (X-ray CT) tests, which can be used to enhance the quality of new designs and prognosis practices for fibre reinforced composites. To reduce the empiricism and conservatism of existing methods, this PhD research systematically has tackled several challenging tasks including: (i) extension of the cohesive interface crack model to multi-phase composites in both 2D and 3D, (ii) development of a new in-house loading rig to support in-situ X-ray CT tests, (iii) reconstruction of low phase-contrast X-ray CT datasets of carbon fibre composites, (iv) integration of X-ray CT image-based models into detailed crack propagation FE modelling and (v) validation of a partially informed multiscale stochastic modelling method by direct comparison with in-situ X-ray CT tensile test results.
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Ghous, Abid Petroleum Engineering Faculty of Engineering UNSW. « 3D imaging and modeling of carbonate core at multiple scales ». Awarded By:University of New South Wales. Petroleum Engineering, 2010. http://handle.unsw.edu.au/1959.4/44606.
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The understanding of multiphase flow properties is essential for the exploitation of hydrocarbon reserves in a reservoir; these properties in turn are dependent on the geometric properties and connectivity of the pore space. The determination of the pore size distribution in carbonate reservoirs remains challenging; carbonates exhibit complex pore structures comprising length scales from nanometers to several centimeters. A major challenge to the accurate evaluation of these reservoirs is accounting for pore scale heterogeneity on multiple scales. This is the topic of this thesis. Conventionally, this micron scale information is achieved either by building stochastic models using 2D images or by combining log and laboratory data to classify pore types and their behaviour. None of these capture the true 3D connectivity vital for flow characterisation. We present here an approach to build realistic 3D network models across a range of scales to improve property estimation through employment of X-ray micro-Computed Tomography (μCT) and Focussed Ion Beam Tomography (FIBT). The submicron, or microporous, regions are delineated through a differential imaging technique undertaken on x-ray CT providing a qualitative description of microporosity. Various 3-Phase segmentation methods are then applied for quantitative characterisation of those regions utilising the attenuation coefficient values from the 3D tomographic images. X-ray micro-CT is resolution limited and can not resolve the detailed geometrical features of the submicron pores. FIB tomography is used to image the 3D pore structure of submicron pores down to a scale of tens of nanometers. We describe the experimental development and subsequent image processing including issues and difficulties resolved at various stages. The developed methodology is implemented on cores from producing wackstone and grainstone reservoirs. Pore network models are generated to characterise the 3D interconnectivity of pores. We perform the simulations of petrophysical properties (permeability and formation resistivity) directly on the submicron scale image data. Simulated drainage capillary pressure curves are matched with the experimental data. We also present some preliminary results for the integration of multiscale pore information to build dual-scale network models. The integration of multiscale data allows one to select appropriate effective medium theories to incorporate sub-micron structure into property calculations at macro scale giving a more realistic estimation of properties.
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Papajová, Gabriela. « Obrazové detektory rentgenového záření pro aplikace v microCT systémech ». Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-316801.
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Diplomová práce se zabývá detektory rentgenového záření pro mikro-CT systémy. Teoretická část zahrnuje standartní typy rentgenových detektorů a požadavky na kvalitu obrazu pro výslednou 3D rekonstrukci. V závěru jsou popsány fyzikální parametry reálných detektorů a metody jejich měření a vyhodnocení.
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Kizhakke, Puliyakote Abhilash Srikumar. « Comprehensive assessment and characterization of pulmonary acinar morphometry using multi-resolution micro x-ray computed tomography ». Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/3120.
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The characterization of the normal pulmonary acinus is a necessary first step in understanding the nature of respiratory physiology and in assessing the etiology of pulmonary pathology. Murine models play a vital role in the advancement of current understanding of the dynamics of gas exchange, particle deposition and the manifestations of diseases such as COPD, Cystic Fibrosis and Asthma. With the advent of interior tomography techniques, high-resolution micro computed tomography (μCT) systems provide the ability to nondestructively assess the pulmonary acinus at micron and sub-micron resolutions. With the application of Systematic Uniform Random Sampling (SURS) principles applied to in-situ fixed, intact, ex-vivo lungs, we seek to characterize the structure of pulmonary acini in mice and study the variations across dimensions of age, location within the lung and strain phenotypes.
Lungs from mice of three common research strains were perfusion fixed in-situ, and imaged using a multi-resolution μCT system (Micro XCT 400, Zeiss Inc.). Using lower resolution whole lung images, SURS methods were used for identification of region-specific acini for high-resolution imaging. Acinar morphometric metrics included diameters, lengths and branching angles for each alveolar duct and total path lengths from entrance of the acinus to the terminal alveolar sacs. In addition, other metrics such as acinar volume, alveolar surface area and surface area/volume ratios were assessed.
A generation-based analysis demonstrated significant differences in acinar morphometry across young and old age groups and across the three strains. The method was successfully adapted to large animals and the data from one porcine specimen has been presented. The registration framework provides a direct technique to assess acinar deformations and provides critical physiological information about the state of alveolar ducts and individual alveoli at different phases of respiration.
The techniques presented here allow us to perform direct assessment of the three-dimensional structure of the pulmonary acinus in previously unavailable detail and present a unique technique for comprehensive quantitative analysis. The acinar morphometric parameters will help develop improved mathematical and near-anatomical models that can accurately represent the geometric structure of acini, leading to improved assessment of flow dynamics in the normal lung.
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Huang, Yan. « Structural Mapping of Paper Towels : Comparison of Twin Laser Profilometry and Synchrotron X-ray Micro-computed Tomography ». Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1281751951.
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Sidlipura, Ravi Kumar Sujith Kumar. « Multi-modal and multiscale image analysis work flows for characterizing through-thickness impregnation of fiber reinforced composites manufactured by simplified CRTM process ». Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Lille Douai, 2024. http://www.theses.fr/2024MTLD0010.
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Cette thèse présente une étude expérimentale pour améliorer le moulage par compression et transfert de résine thermoplastique (CRTM), axée sur l'efficacité industrielle, la durabilité et la recyclabilité, conformément aux objectifs de développement durable pour l’industrie, l’innovation et l’action climatique. En abordant la complexité de l'écoulement de la résine à plusieurs échelles dans le CRTM, cette recherche étudie l'écoulement transversal (à travers l’épaisseur) et la porosité induite par le processus à l'échelle méso des faisceaux de fibres de verre afin d'améliorer l'uniformité de l'imprégnation et le contrôle du compactage, en faisant le lien entre les cadres théoriques et les applications évolutives. L’étude est conduite sur une préforme, constituées de 6 couches de fibres de verre UD ([0/90]3) et d’une matrice thermoplastique en polypropylene (PP) mise en forme par un procédé CRTM . Un procédé « CRTM simplifié » permettant de contrôler la direction du front de matière est développé sur une presse industrielle, pilotée en déplacement. Trois configurations de procédé sont analysées : Configuration 1 (Référence) : configuration de type « film stacking » comme base de comparaison de la distribution de la résine et de la structure des fibres. Configuration 2 (CRTM simplifié) : Compression contrôlée par déplacement, les films de polymères formant initialement une couche unique en surface de la préforme. Configuration 3 (CRTM simplifié avec scellement des bords) : Compression améliorée avec un dispositif d’étanchéité limitant les fuites de résine en périphérie de la préforme et assurant un écoulement transversal. Un protocole d’analyse d'imagerie 2D est proposé, incluant l’analyse en lumière polarisée, la microscopie à fluorescence et la microscopie électronique à balayage pour caractériser qualitativement et quantitativement les taux de porosités au niveau des mèches et des plis de tissus. Un processus original de polissage en deux étapes permet de préserver l'intégrité de la surface. L'étude est complétée par une évaluation fine des mécanismes d'imprégnation à l'aide de la technique d'inspection hélicoïdale en microtomographie à rayon-X (micro-CT). Les résultats démontrent que les paramètres de compaction influencent directement le niveau d'imprégnation, atteignant une limite d'imprégnation. Cette thèse établit une démarche d’analyse du procédé CRTM pour des composites thermoplastiques haute performance, en vue d’une maitrise et d’une optimisation du procédé. Elle offre des perspectives sur des protocoles d’analyse précis basés sur l’étude à différentes échelles, améliorant la compréhension de l'interaction entre l'imprégnation et la perméabilité. Ces résultats répondent aux exigences de précision dans des secteurs tels que l'automobile et l'aérospatiale, où les composites CRTM sont essentiels pour les applications structurellesThis thesis presents an experimental study to advance thermoplastic Compression Resin Transfer Molding (CRTM), focusing on industrial efficiency, sustainability, and recyclability goals aligned with the Sustainable Development Goals for Industry, Innovation, and Climate Action. By addressing multi-scale resin flow complexity in CRTM, this research investigates transverse flow and process-induced porosity at the meso scale of glass fiber bundles to improve impregnation uniformity and compaction control, bridging theoretical frameworks with scalable applications. The study focuses on a thermoplastic polypropylene matrix reinforced with six layers of bidirectional UD woven glass fibers ([0/90]3) consolidated on a CRTM setup. The “Simplified CRTM” method is developed on an industrial press, using displacement-controlled compaction ratios. This method omits active resin injection, relying on a uniformly distributed viscous polymer pool beneath the unsaturated preform to drive resin flow uniformly with a unidirectional flow path. Controlled displacement and pressure optimize resin paths, manage fiber volume fraction, and reduce porosity. Three multi-step compaction configurations are evaluated: Configuration 1 (Reference): Uses force compaction as a baseline for comparing resin distribution and fiber structure. Configuration 2 (simplified CRTM): Displacement-controlled compaction enhances resin infiltration but faces challenges like edge race-tracking and fiber volume fraction (Vf) variability, affecting impregnation. Configuration 3 (simplified CRTM with Edge Sealing): Introduces high-temperature sealant tape at mold edges, limiting resin escape, maintaining transverse flow, and reducing porosity and race-tracking. Configuration 3 edge-sealing technique establishes a reproducible process for high quality CRTM composites. An advanced 2D multi-modal imaging protocol, tailored for partially impregnated samples produced via simplified CRTM with unfilled spaces and fragile microstructures, includes polarized light microscopy, fluorescence microscopy, and scanning electron microscopy for qualitative and quantitative characterization. An original two-step polishing process preserves surface integrity, and image post-processing workflows quantify impregnation quality and void distribution. The study is completed with a fine evaluation of the impregnation mechanisms using X-ray micro computed tomography technique (micro-CT) relying on helicoidal inspection method. Results demonstrate that compaction parameters directly impact impregnation level, reaching an impregnation limit. This thesis establishes a scalable, data-driven CRTM framework bridging laboratory experimentation with industrial requirements for high-performance thermoplastic composites. It offers insights into streamlined protocols and microstructure-based analysis, enhancing understanding of the interplay between impregnation and permeability in CRTM. These findings align with precision demands in sectors like automotive and aerospace, where CRTM composites are crucial for structural applications
Chapitres de livres sur le sujet "X-Ray Micro-CT (Micro-Tomography)"
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Molteni, Roberto. « X-Ray Imaging : Fundamentals of X-Ray ». Dans Micro-computed Tomography (micro-CT) in Medicine and Engineering, 7–25. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-16641-0_2.
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Erdem, Savaş, et Serap Hanbay. « X-Ray Computed Tomography Technique in Civil Engineering ». Dans Micro-computed Tomography (micro-CT) in Medicine and Engineering, 277–88. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-16641-0_17.
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Çubukçu, H. Evren. « Application of X-Ray Microtomography in Pyroclastic Rocks ». Dans Micro-computed Tomography (micro-CT) in Medicine and Engineering, 289–302. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-16641-0_18.
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Salmon, Phil. « Application of Bone Morphometry and Densitometry by X-Ray Micro-CT to Bone Disease Models and Phenotypes ». Dans Micro-computed Tomography (micro-CT) in Medicine and Engineering, 49–75. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-16641-0_5.
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Yang, Xiaoliang, Xuequan Wang, Zhe Pan, Jie Liu et Jiandong Luo. « Preliminary Application of CT Technology in Non-destructive Testing of Nuclear Fuel Elements ». Dans Springer Proceedings in Physics, 98–106. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1023-6_10.
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AbstractWith the emergence of various novel fuel elements, traditional X-ray test technologies refer to national standards that have gradually been unable to meet the non-destructive testing (NDT) requirements for these novel fuel elements. As a new NDT technology, industrial computed tomography (CT) has great potential for NDT of nuclear fuel elements. In this paper, through a personalized transformation of self-developed X-ray equipment, we carried out CT scanning imaging experiments up to more than 400 kV on pellet-shell gap in rod-shaped fuel elements, a high-density annular component, and a tungsten-based workpiece. Not only that, after three-dimensional reconstruction and image analysis, it was found that sub-millimeter internal void defects could be detected. Furthermore, size measurements were carried out through image analysis which achieved a relative error of 5%. A conservative conclusion can be drawn from this research: industrial CT, including but not limited to micro-CT, high-energy X-ray CT, etc., has an optimistic future in testing internal defects and measuring internal dimensions of novel fuel elements.
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Fukuda, D., Y. Nara, D. Mori et K. Kaneko. « Sealing Behavior of Fracture in Cementitious Material with Micro-Focus X-Ray CT ». Dans Advances in Computed Tomography for Geomaterials, 148–55. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118557723.ch18.
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Nazhat Yahya et Airey David. « Applications of high speed photography and X-ray computerised tomography (Micro CT) in dynamic compaction tests ». Dans Deformation Characteristics of Geomaterials. IOS Press, 2011. https://doi.org/10.3233/978-1-60750-822-9-421.
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Dynamic compaction is an efficient ground improvement technique for loose granular soils. The improvement is achieved by controlled high energy tamping. Its effects vary with soil properties, energy input and the pattern of treatment. However, the depth and extent of soil improvement are both difficult to predict and to quantify. To provide data on the mechanics of dynamic compaction high speed digital photography coupled with X-ray computerised tomography (Micro CT) and digital image correlation analysis has been used in model compaction tests conducted on dry sand under plane strain conditions. The high speed digital photography suggests that compaction (shock) bands are responsible for the densification beneath the impact, and a series of photographs are included to show the evolution of these bands. To verify that these bands were not an artefact of the photography X-ray computerised tomography (Micro CT) was utilised to quantitatively measure the void ratio in the vicinity of a compaction band. This attempted verification was not conclusive because of some limitations of the Micro CT procedure which are discussed.
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Frost, Jovyn K. T., et Roswitha Schröder. « Atomic Force Microscopy (AFM) and X-Ray Micro-Computed Tomography (Micro-CT) : Applications in Cell Wall Imaging of Softening Fruit ». Dans Encyclopedia of Food Chemistry, 8–14. Elsevier, 2019. http://dx.doi.org/10.1016/b978-0-08-100596-5.21680-6.
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Kikkawa N., Pender M.J., Orense R.P. et Matsushita E. « Behaviour of pumice sand during hydrostatic and K ». Dans Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering. IOS Press, 2009. https://doi.org/10.3233/978-1-60750-031-5-812.
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In order to understand the characteristics of pumice sand, we scanned pumice particles using micro X-ray computed tomography (X-ray CT), which showed that pumice particles have not only surface voids but also internal voids. Therefore, pumice sand is lighter than quartz sands and also is crushable. In addition, from our previous research, the relative density of pumice sand can not be estimated from conventional CPT testing. Because of this unique behaviour, there is a need for more experimental study of this material to fully understand its geotechnical properties. First, we performed hydrostatic compression tests on loose pumice sand and monitored the volume change with elapsed time during loading and unloading. After these tests, the particle-size distribution (PSD) was measured. Second, in order to distinguish the differences in stress relaxation between loose and dense sand which might occur during CPT testing, Kocompression tests were performed at various displacement rates, from 0.5mm/min to 25mm/sec. The final compression was about 33% of the original length of the specimens. After compression, the maximum displacement was held constant for a specified period of time and the relaxation of the axial stress was monitored during this time. From these results, the stress relaxation of loose sand was slightly larger than that of dense sand, presumably because loose sand has more spaces for rearrangement of particles during the stress relaxation process.
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Ramaraj, Kottaimalai, Pallikonda Rajasekaran Murugan, Gautam Amiya, Vishnuvarthanan Govindaraj, Muneeswaran Vasudevan, Thirumurugan, Yu-Dong Zhang, Sheik Abdullah et Arunprasath Thiyagarajan. « Blockchain Associated Machine Learning Approach for Earlier Prognosis and Preclusion of Osteoporosis in Elderly ». Dans Advances in Computing Communications and Informatics, 1–24. BENTHAM SCIENCE PUBLISHERS, 2024. http://dx.doi.org/10.2174/9789815165432124070003.
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Osteoporosis (OP), or porous bone, is a severe illness wherein an individual's bones weaken, increasing the likelihood of fractures. OP is caused by micro-architectural degradation of bone tissues, which raises the probability of bone fragility and can result in bone fractures even when no force is placed on it. Estimating bone mineral density (BMD) is a prevalent method for detecting OP. For women who have reached menopause, prompt and precise forecasts and preventative measures of OP are essential. BMD can be measured using imaging methods like Computed Tomography (CT) and Dual Energy X-ray Absorptiometry (DEXA/DXA). Blockchain (BC) is a revolutionary technique utilized in the health sector to store and share patient information between clinics, testing centres, dispensaries, and practitioners. The application of Blockchain could detect drastic and even serious errors. As an outcome, it may improve the confidentiality and accessibility of medical information interchange in the medical field. This system helps health organizations raise awareness and enhance the evaluation of health records. By integrating blockchain technology with machine learning algorithms, various bone ailments, including osteoporosis and osteoarthritis, can be identified earlier, which delivers a report regarding the prediction of fracture risk. The developed system can assist physicians and radiologists in making more rapid and better diagnoses of the affected ones. In this work, we developed a completely automated mechanism for suspicious osteoporosis patients that uses machine learning techniques to improve prognosis and precision via different processes. Here, we developed a computerized system that effectively integrates principal component analysis (PCA) with the weighted k-nearest neighbours algorithm (wkNN) to identify, predict, and classify the BMD scores as usual, osteopenia, and osteoporosis. The ranked results are validated with the DEXA scan results and by the clinicians to demonstrate the efficacy of the machine learning techniques. The laboratories use BC to safely and anonymously share the findings with the patients and doctors.
Actes de conférences sur le sujet "X-Ray Micro-CT (Micro-Tomography)"
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Allan, Harry, Oriol Roche i Morgó, Carlos Navarrete-Leon, Yunpeng Jia et Marco Endrizzi. « Sub-second dynamic x-ray micro-CT and fast phase-sensitive multi-contrast micro-CT with a laboratory source ». Dans Developments in X-Ray Tomography XV, sous la direction de Bert Müller et Ge Wang, 22. SPIE, 2024. http://dx.doi.org/10.1117/12.3028059.
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Hildebrand, Torben, Gerard B. Lemonche, Håvard J. Haugen, Goran Petrovski et Liebert P. Nogueira. « Contrast-enhanced micro-CT for visualization of cell distribution in hydrated human cornea ». Dans Developments in X-Ray Tomography XV, sous la direction de Bert Müller et Ge Wang, 72. SPIE, 2024. http://dx.doi.org/10.1117/12.3026984.
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Roche i Morgo, Oriol, Yunpeng Jia, Harry Allan, Adam Doherty, Carlos Navarrete-León, Alberto Astolfo, Licai Jiang, Joseph D. Ferrara et Marco Endrizzi. « A new user facility with flexible multi-scale, multi-contrast micro-CT capabilities ». Dans Developments in X-Ray Tomography XV, sous la direction de Bert Müller et Ge Wang, 7. SPIE, 2024. http://dx.doi.org/10.1117/12.3028029.
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Hildebrand, Torben, Qianli Ma, Catherine Anne Heyward, Håvard J. Haugen et Liebert P. Nogueira. « Advanced soft tissue visualization in conjunction with bone structures using contrast-enhanced micro-CT ». Dans Developments in X-Ray Tomography XV, sous la direction de Bert Müller et Ge Wang, 17. SPIE, 2024. http://dx.doi.org/10.1117/12.3027063.
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Zhang, Yibing, Yile Fang, Vigjna Abbaraju, Jeffrey N. Anker, Wenxiang Cong, Ge Wang et Changqing Li. « Oxygenation imaging of deep targets at high resolution with an x-ray luminescence micro-CT system ». Dans Developments in X-Ray Tomography XV, sous la direction de Bert Müller et Ge Wang, 43. SPIE, 2024. http://dx.doi.org/10.1117/12.3027929.
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Saites, F., G. Wang, R. Guo, K. Mannhardt et A. Kantzas. « Coalbed Characterization Studies With X-Ray Computerized Tomography (CT) and Micro CT Techniques ». Dans Canadian International Petroleum Conference. Petroleum Society of Canada, 2006. http://dx.doi.org/10.2118/2006-027.
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Sayama, Toshihiko, Hiroyuki Tsuritani, Kentaro Uesugi, Akira Tsuchiyama, Tsukasa Nakano, Hideyuki Yasuda, Takeshi Takayanagi et Takao Mori. « Nondestructive Evaluation of Thermal Phase Growth in Solder Ball Micro-Joints by Synchrotron Radiation X-Ray Micro-Tomography ». Dans ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems collocated with the ASME 2005 Heat Transfer Summer Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/ipack2005-73083.
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In high-density packaging technology, one of the most important problems is reliability of the micro-joints connecting LSI (Large Scale Integrated Circuit) chips to PCBs (Printed Circuit Boards) electrically and mechanically. Development of nondestructive testing methods with high spatial resolution is expected to enhance the reliability. Our research group has developed an X-ray micro-tomography system called SP-μCT at the beamline BL47XU in SPring-8, the largest synchrotron radiation facility in Japan. In this work, SP-μCT was applied to three-dimensional evaluation of microstructure evolution; that is, phase growth due to thermal cyclic loading in solder ball micro-joints. Simulating solder micro-joints used in a flip chip, specimens were fabricated by joining a Sn-Pb eutectic solder ball 100 μm in diameter to a steel pin in the usual reflow soldering process. The phase growth process was determined by observation of the CT images obtained consecutively at the fixed point of the target joining. In the reconstructed CT images, the distribution of the constituent phases in Sn-Pb eutectic solder was identified based on the estimation value of the X-ray linear attenuation coefficient. The following results were obtained. First, each phase involves not dispersing particles but a three-dimensionally monolithic structure just like a sponge. Second, the phase growth proceeds in such a way that the average phase size to the 4th power increases proportionally to the number of cycles. Finally, in the vicinity of the joining interface, more rapid phase growth occurs in comparison to the other regions because local thermal strain due to the mismatch of thermal expansion leads to remarkable phase growth. Consequently, the microstructure images obtained by SP-μCT bring us useful information to evaluate the reliability of micro-joints.
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Orlov, Maksim Sergeevich, Pavel Valeriyevich Roschin, Ivan Aleksandrovich Struchkov et Vladimir Tarasovich Litvin. « The Application of X-ray Micro Computed Tomography (Micro-CT) of Core Sample for Estimation of Physicochemical Treatment Efficiency ». Dans SPE Russian Petroleum Technology Conference. Society of Petroleum Engineers, 2015. http://dx.doi.org/10.2118/176600-ms.
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Karim, Azharul, M. M. Rahman, M. M. Billah et M. I. H. Khan. « Microstructural characterization of apple tissue during drying using X-Ray microtomography ». Dans 21st International Drying Symposium. Valencia : Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/ids2018.2018.8351.
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This study aims to investigate the complex microstructural changes in plant-based food materials during drying by using X-ray micro-computed tomography (X-ray µCT) along with the image analysis. The apple samples were dried at 60 °C and tested using X-ray µCT at different stages of drying. The porosity, cell and pore size distribution were determined from the micro-CT data set. It was observed that significant changes in porosity, cell and pore size distribution take place at different drying times and moisture contents. X-ray µCT can serve as a very promising tool to elucidate the evolution of the food microstructure during the drying process. Keywords: Food drying, characteristics, X-ray microtomography, nondestructive evaluation
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Tsuritani, Hiroyuki, Toshihiko Sayama, Yoshiyuki Okamoto, Takeshi Takayanagi, Kentaro Uesugi et Takso Mori. « Application of Synchrotron Radiation X-Ray Micro-Tomography to Nondestructive Evaluation of Thermal Fatigue Damage in Flip Chip Interconnects ». Dans ASME 2007 InterPACK Conference collocated with the ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ipack2007-33170.
Texte intégralRésumé :
A synchrotron radiation X-ray micro-tomography system called SP-μCT with a spatial resolution of about 1μm has been developed in SPring-8, the largest synchrotron radiation facility in Japan. In this work, SP-μCT was applied to the nondestructive evaluation of microstructure evolution; that is phase growth, and micro-crack propagation appearing as thermal fatigue damage in solder micro-bumps of flip chip interconnects. The observed specimens have a flip chip structure joined by Sn-37wt%Pb eutectic solder bumps 100μm in diameter. A thermal cycle test was carried out, and the specimens were picked up at any number of cycles. The solder bumps were observed by using SP-μCT at the beamlines BL47XU and BL20XU in SPring-8. An X-ray energy of 29.0 keV was selected to obtain absorption images with a high contrast between the Sn-rich and the Pb-rich phases. Additionally, a refraction-contrast imaging technique was applied to visualize fatigue cracks in the solder bumps. The obtained CT (Computed Tomography) images clearly show the process of phase growth and crack propagation due to the thermal cyclic loading of the same solder bump; such information has not been obtained at all by industrially-used X-ray CT systems. In the initial state, the Pb-rich phase was dispersed with characteristic shape, which appears in reflow soldering process. Remarkable phase growth was also observed clearly as the thermal cycle test proceeded. When the loading reached 300 cycles, fatigue cracks appeared in the corners of the interfaces between the solder bump and the Cu pad. The CT images enabled us to evaluate the lifetime of the bumps to the initiation of fatigue cracks by estimating the increase in a phase growth parameter, which corresponds to the accumulation of fatigue damage in the solder joints. The results showed that the estimated lifetime strongly agreed with the average value, which was determined by SEM (Scanning Electron Microscope) destructive observations. As the thermal cycle proceeded, the cracks propagated gradually to the inner region of the solder bump. From the CT images, the average propagation rate was calculated, and the mean of the total fatigue lifetime was estimated to be less than 1800 cycles. These results show the possibility that nondestructive testing by a synchrotron radiation X-ray micro CT system is useful for evaluating the thermal fatigue lifetime in micro-joints.
Rapports d'organisations sur le sujet "X-Ray Micro-CT (Micro-Tomography)"
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Young, Steven. Imaging APO-BMI with Micro X-ray Computed Tomography (CT). Office of Scientific and Technical Information (OSTI), mars 2021. http://dx.doi.org/10.2172/1772371.
Texte intégral
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Aarle, Wim van, et Wolfgang Ludwig. X-Ray Diffraction Contrast Tomography in micro-CT Lab Source Systems. Fort Belvoir, VA : Defense Technical Information Center, mai 2014. http://dx.doi.org/10.21236/ada604806.
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