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The objective of this study was to develop a replica method for producing zirconia-reinforced bioactive glass (ZRBG) porous structures for bone repair. Four different types of porous structures were produced: zirconia (G1), 58S BG-coated zirconia (G2), zirconia-reinforced BG (G3) and 58S BG-coated zirconia-reinforced BG (G4). A complete characterization of the specimens was performed via SEM-EDS, Archimedes method, 3D X-ray micro-tomography, micro-indentation, compressive strength tests and SBF immersion tests. G3 and G4 specimens presented a BG matrix (~ 33% glassy phase) with dispersed zirconia particles. The porosity of the specimens ranged from 86% up to 93%. BG58S-zirconia groups G3 and G4) exhibited lower YM (38.76 ± 11.20 GPa and 43.49 ± 2.16 GPa) than that of G1 monolithic zirconia specimens (94.39 ± 12.62 GPa), which were more compatible to that of the bone. No significant difference in compressive strength between BG58S-zirconia (G3: 0.41 ± 0.20 MPa; G4: 0.45 ± 0.11 MPa) and zirconia (G1: 0.32 ± 0.11 MPa) was detected observed (p > 0.05). In vitro SBF tests showed a potential bioactivity for ZRBG porous structures.

Grinding wheel content characterization is still mainly based on empirical tests, lacking the necessary scientific approach. To further develop the current existing methodology, this study introduces a method to characterize the grinding wheel structure and content, using microscale X-ray tomography allied with image processing techniques. An X-ray tomography characterization was performed on four different conventional grinding wheels, each containing a specific mixture of electro-fused and sol-gel aluminum oxide abrasives as grits. The grinding wheels were evaluated in terms of volumetric phase fraction, representative elementary volume, phase, and pore size distribution. The results showcased that even though the grinding wheels presented the same manufacturing label (in terms of mechanical properties), the volumetric phase fraction between the grinding wheels was significantly different. This study aggregates the empirical knowledge used to characterize grinding wheels, opening possibilities for academic and industrial research.

Rhodolith beds built by free-living coralline algae are important ecosystems for marine biodiversity and carbonate production. Yet, our mechanistic understanding regarding rhodolith physiology and its drivers is still limited. Using three rhodolith species with different branching morphologies, we investigated the role of morphology in species' physiology and the implications for their susceptibility to ocean acidification (OA). For this, we determined the effects of thallus topography on diffusive boundary layer (DBL) thickness, the associated microscale oxygen and pH dynamics and their relationship with species' metabolic and light and dark calcification rates, as well as species' responses to short-term OA exposure. Our results show that rhodolith branching creates low-flow microenvironments that exhibit increasing DBL thickness with increasing branch length. This, together with species' metabolic rates, determined the light-dependent pH dynamics at the algal surface, which in turn dictated species' calcification rates. While these differences did not translate in species-specific responses to short-term OA exposure, the differences in the magnitude of diurnal pH fluctuations (~ 0.1-1.2 pH units) between species suggest potential differences in phenotypic plasticity to OA that may result in different susceptibilities to long-term OA exposure, supporting the general view that species' ecomechanical characteristics must be considered for predicting OA responses. UID/Multi/04326/2019, 426215/2016-8, 1521610, HO 5439/2-1 info:eu-repo/semantics/publishedVersion

Made available in DSpace on 2021-06-25T15:01:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Universidade Federal de Santa Catarina Micropaleontology is crucial branch of Earth Sciences, with a pivotal role in the success of the oil and gas industry over the decades. This sector of paleontology is based on the taxonomical description of microfossils, which encompass fossils with size variation from 0.001 mm to 1 m. Normally these microorganisms have a high rate on preservation, thus they are widely accepted as reliable evidence to infer about paleodepositional settings and paleoclimate change. Furthermore, microfossils are critical to understanding the evolution through time, being many of them recognized as index fossil and providing useful biozones to correlation. Since 1950, microfossils have been taxonomically described mainly by stereomicroscopes. However, as the technology progress, traditional ways to study these organisms are challenged and improved by nondestructive three-dimensional imaging techniques, as X-ray tomographic microscopy (SRXTM), three-dimensional X-ray microscopy (3DXRM), the X-ray computed microtomography (microCT) and X-ray computed nanotomography (nanoCT). Recently, one of the most compelling research areas in micropaleontology is the desire to automatize and enhance the details of systematic classification. Thereby, an increasing number of researches have applied the high-resolution X-ray analysis aiming to improve the morphological, taxonomic and taphonomic examination. Most of them have detailed the enhancement provided by the technique when compared with the standard microscopes, and raised questions about the traditional characters used on the microfossil systematic taxonomy. Nevertheless, even with the surpassing detail on microfossil characterization, the application of microCT has been hampered by the costs and sometimes by the needs of specific computer skill. Thus, this research has evaluated the use of microCT as the technique to classify a random bulk of microfossil (comprising foraminifers, ostracods, radiolarians, gastropods and echinoderms) with no further software treatment. No standard microscope analysis was performed. Despite chemical composition of microfossils, most of the specimens morphology, especially internal structures, have been easily acquired and analyzed. 96% of the microfossils of the dataset were identified at least on genus level. Irrespective of the deepness of detail, when considering the overall taxonomic identification, the microCT seems to be effective as the standard microscope. Nonetheless, when problematic specimens are evaluated, the microCT seems to be a more reliable and practical tool than other methods as Scanning Electron Microscopy. Thus, the technique can be used solo or as a complementary method to the stereomicroscope. Additionally, the high-resolution has the potential to lead to the expected automatized & nbsp;micropaleontology, since they can provide numerous images in several planes. This may create a strong database necessary to machine learning and computer identification. Univ Fed Santa Catarina, Dept Mech Engn, Lab Meios Porosos & Propriedades Termofis LMPT, BR-88040535 Florianopolis, SC, Brazil Univ Fed Pernambuco, Dept Geol, Lab Micropaleontol Aplicada LMA, BR-50740540 Recife, PE, Brazil Univ Vale Rio dos Sinos, Inst Tecnol Micropaleontol, Itt Fossil, Sao Leopoldo, RS, Brazil Univ Vale Rio dos Sinos, Geol Grad Program, BR-93022750 Sao Leopoldo, RS, Brazil Univ Estadual Paulista, Fac Ciencias Bauru, Dept Ciencias Biol, Ave Engenheiro Luiz Edmundo Carrijo Coube, BR-17033360 Bauru, SP, Brazil Univ Fed Santa Catarina, Dept Geol, Lab Geoquim LABGEOQ, Rua Engn Agron Andrei Cristian Ferreira S-N, BR-88040535 Florianopolis, SC, Brazil Univ Estadual Paulista, Fac Ciencias Bauru, Dept Ciencias Biol, Ave Engenheiro Luiz Edmundo Carrijo Coube, BR-17033360 Bauru, SP, Brazil

The applicability of computational analysis to paleontological images ranges from the study of the animals, plants and evolution of microorganisms to the simulation of the habitat of living beings of a given epoch. It also can be applied in several niches, such as oil exploration, where there are several factors to be analyzed in order to minimize the expenses related to the oil extraction process. One factor is the characterization of the environment to be explored. This analysis can occur in several ways: use of probes, extraction of samples for petrophysical components evaluation, the correlation with logs of other drilling wells and so on. In the samples extraction part the Computed Tomography (CT) is of importance because it preserves the sample and makes it available for several analyzes. Based on 3D images generated by CT, several analyzes and simulations can be performed and processes, currently performed manually and exhaustively, can be automated. In this work we propose and validate a method for fully automated microfossil identification and extraction. A pipeline is proposed that begins in the scanning process and ends in an identification process. For the identification a Deep Learning approach was developed, which resulted in a high rate of correct microfossil identification (98% of Intersection Over Union). The validation was performed both through an automated quantitative analysis based upon ground truths generated by specialists in the micropaleontology field and visual inspection by these specialists. We also present the first fully annotated MicroCT-acquired publicly available microfossils dataset.

Computational analysis applicability to paleontological images ranges from the study of the evolution of animals, plants and microorganisms to the habitat simulation of living beings from a specific epoch. It can also be applied in several niches, e.g. oil exploration, where several factors can be analyzed in order to minimize costs related to oil extraction. One specific factor is the characterization of the environment to be explored. This analysis can occur in several ways: use of probes, samples extraction, correlation with logs of other drilling wells and so on. During the samples extraction phase, the Computed Tomography (CT) is of extreme importance, since it preserves the sample and makes it available for several analyses. Based on 3D images generated by CT, analyses and simulations can be performed, and processes currently performed manually and exhaustively, can be automated. In this work, we propose and validate a method for fully automated microfossil identification and segmentation. A pipeline is proposed that begins with scanning and ends with the microfossil segmentation process. For the microfossil segmentation, a Deep Learning approach was developed, which resulted in a high rate of correct microfossil segmentation (98% IOU). The validation was performed both through an automated quantitative analysis and visual inspection. The study was performed on a limited dataset, but the results provide evidence that our approach has potential to be generalized to other carbonatic rock substrates. To the extent of the authors' knowledge, this paper presents the first fully annotated MicroCT acquired microfossils dataset made publicly available.

This study reveals the pore-scale details of oil mobilisation and recovery from a carbonate rock upon injection of aqueous nanoparticle (NP) suspensions. X-ray computed micro-tomography (μCT), which is a non-destructive imaging technique, was used to acquire a dataset which includes: (i) 3D images of the sample collected at the end of fluid injection steps, and (ii) 2D radiogram series collected during fluid injections. The latter allows monitoring fluid flow dynamics at time resolutions down to a few seconds using a laboratory-based μCT scanner. By making this dataset publicly available we enable (i) new image reconstruction algorithms to be tested on large images, (ii) further development of image segmentation algorithms based on machine learning, and (iii) new models for multi-phase fluid displacements in porous media to be evaluated using images of a dynamic process in a naturally occurring and complex material. This dataset is comprehensive in that it offers a series of images that were captured before/during/and after the immiscible fluid injections.

This work provides new insights into the dynamics of silica nanoparticle-based removal of organic fluids (here oil) from naturally occurring porous media. We have used 4D (time-resolved 3D) imaging at pore-scale using X-ray computed micro-tomography (μCT) technique. The captured 3D tomographic time-series data reveal the dynamics of immiscible oil displacement from a carbonate rock upon injection of nanoparticle (NP) suspensions (0.06 and 0.12 wt% SiO2 in deionised water). Our analysis shows significant pore-scale remobilisation of initially trapped oil upon injection of the NP suspensions, specifically, at higher concentration. Our data shows that oil clusters become significantly smaller with larger fluid/fluid interface as a result of the higher concentration NP injection. This paper demonstrates that use of 2D radiograms collected during fluid injections allows monitoring flow dynamics at time resolutions down to a few seconds using conventional laboratory-based μCT scanners. Here, as an underlying mechanism for oil remobilisation, we present the first 4D evidence of in-situ formation of an oil in water emulsion induced by nanoparticles.

Neste trabalho desenvolve-se um metodo semianalitico para calcular a permeabilidade absoluta de rochas a partir de imagens microtomograficas. Enfatiza-se as questoes fenomenologicas do modelo, bem como suas hipoteses, e nesse sentido aponta-se alguns equivocos encontrados na literatura. A metodologia e aplicada a tres amostras de rochas areniticas. O metodo foi capaz de predizer a ordem de grandeza para as duas amostras que possuem valores experimentais disponiveis. Para a amostra que nao apresenta valor experimental de permeabilidade, o resultado concorda com a ordem de grandeza prevista por outros metodos. In this paper we develop a semi-analytical procedure to determine the absolute permeability of rocks from microtomographical images. We underscore all phenomenological assumptions and hypothesis, we also point out some misleadings in current literature. The methodology is applied to three samples of sandstone rocks. The method was able to predict the order of magnitude for the two samples that have available experimental values. For the sample that does not show experimental permeability value, the result agrees with the order of magnitude predicted by other methods.

This work had the objective to determine the Hydraulic Conductivity K(theta) function for different depth levels z, of columns of undisturbed soil, using the gamma ray transmission technique applied to the Sisson method. The results indicated a growing behavior for K(theta) and a homogeneous soil density, both in relation to the increase of the depth. The methodology of gamma ray transmission showed satisfactory results on the determination of the hydraulic conductivity in columns of undisturbed soil, besides being very reliable and a nondestructive method.O estudo da condutividade hidráulica para solos não saturados é essencial quando aplicado às situações relacionadas à irrigação, drenagem e transporte de nutrientes no solo, é uma importante propriedade para desenvolvimentos de culturas agrícolas. Este trabalho tem o objetivo de determinar a função Condutividade Hidráulica K(teta), em diferentes níveis z de profundidade, em colunas de solo indeformado, utilizando a transmissão de raios gama aplicada ao método de Sisson. Os resultados indicam um comportamento crescente para K(teta) e uma densidade de solo homogênea, ambos em relação ao aumento da profundidade. A metodologia de transmissão de raios gama mostrou resultados bastante satisfatórios na determinação da condutividade hidráulica em colunas de solo indeformado, além de ser muito confiável e não destrutivo.

No presente trabalho, tratamos de um problema vindo das ciências aplicadas, a potencialização da extração petrolífera, com o objetivo de destacar seu caráter interdisciplinar. Acompanhamos as principais etapas da determinação de parâmetros petrofísicos de rochas via simulação de fenômenos físicos. Intentamos a exposição dos conceitos pertinentes e nos referimos à literatura para detalhes técnicos específicos. A importância dos ensaios experimentais no desenvolvimento de algoritmos simulatórios, assim como a relevância da colaboração de profissionais de diferentes áreas para uma pesquisa científica abrangente são abordados em uma breve discussão no final do texto. A intenção é mostrar a amplitude das aplicações da física, discutindo as aproximações e limitações da descrição do problema em questão. In this paper, we study the problem of oil extraction from a perspective of the applied sciences with the aim to highlight the interdisciplinarity of this subject. We follow the main stages of the determination of petrophysical rock parameters via simulation of physical phenomena. We restrict the presentation of relevant concepts and refer to the literature for specific technical details. The importance of experimental trials in developing simulations, as well as the importance of the collaboration of professionals from different areas for a comprehensive scientific research are addressed in a brief discussion at the end of the text. The intention is to show the breadth of applications of physics, discussing the approximations and limitations of the description of the discussed problem.

Anderson Camargo Moreira1*, Otavio Portezan Filho2, Fabio Henrique de Moraes Cavalcante3 and Carlos Roberto Appoloni2 1Programa de Pos Graduacao em Ciencias e Engenharia de Materiais/EMC, Universidade Federal de Santa Catarina – UFSC, 2Depto. de Fisica, Universidade Estadual de Londrina – UEL, 3Centro de Fisica Nuclear, Instituto Superior de Engenharia/DEEA/ISEL, Universidade de Lisboa, 1,2Brasil 3Portugal

Neste trabalho é apresentada a aplicabilidade das técnicas de Microtomografia de Raios X eTransmissão de Raios Gama na caracterização microestrutural de variados tipos demateriais. Foram determinadas proprieades como porosidade total média, distribuição de tamanho de poros e coeficiente de auto correlação que permite a reconstrução de modelos 3D, realizados para dois tipos de amostras. Foram analisadas sete pastilhas cerâmicas de Alumina (Al2O3), sete pastilhas de Carbeto de Boro (B4C), três amostras de rocha arenito basáltico e uma amostra de Titânio poroso. Na técnica de Transmissão de Raios Gama foram empregados um detector de NaI(Tl) com cristal de 2" x 2", fonte de 241Am com 59,53keV e 100mCi, mesa micrométrica automatizada de movimentação de amostra e eletrônica nuclear padrão de espectrometria gama. Foram também adotados dois sistemas microtomográficos, o sistema Fein Focus constituído por um tubo de raios X que opera com tensão máxima de 160kV e corrente de 0,3 a 1,1mA, câmera CCD e sistema de movimentação de amostra, e o sistema Skyscan modelo 1072 que trabalha com um tubo de raios X de tensão e corrente máximas de 100kV e 100µA e câmera CCD. As pastilhas cerâmicas, analisadas pela técnica de Transmissão de Raios Gama, apresentaram a maioria dos dados de porosidades com intervalos de confiança menores e dentro dos intervalos de confiança fornecidos pelo fabricante. A amostra de Titânio poroso foi analisada pelas duas técnicas, suas imagens microtomográficas foram obtidas com o sistema Fein Focus com resolução espacial de 17µm. Esta apresentou, para ambas técnicas, alta porosidade que lhe permite ser aplicável para sua finalidade. As amostras de rocha foram analisadas com o sistema Skyscan, que alcançou resoluções de imagens de 19µm, 11µm e 3,8µm para cada amostra. As resoluções de 11µm e 3,8µm foram as que geraram melhores seções 2D de suas respectivas amostras e, conseqüentemente, dados de porosidades mais confiáveis. A resolução de 3,8µm foi a que melhor quantificou os dados de distribuição de tamanho de poro, mostrando informação ocultada pela resolução de 11µm, mostrando que poros com raios de 15 a 45µm são predominantes constituindo 57% da fase porosa da amostra, e apenas 1% dela é constituída por poros com raio de até 3,8µm. Tais resultados mostram que resolução de imagem melhor que 3,8µm apenas se faz necessária para casos mais específicos. This work presents the application of the X-Ray Microtomography and Gamma Ray Transmission techniques for the microstructure characterization of different kinds of materials. Total porosity, pore size distribution and the two point correlation functions were measured. The two point correlation function, which allows the reconstruction of 3D models, was carried out for two samples. Seven ceramic tablets of Alumina (Al2O3), seven tablets of Boron Carbide (B4C), three samples of sedimentary rocks and one sample of Titanium foam were analyzed. The experimental set up for the Gamma Ray Transmission technique consisted of: a 2" x 2" crystal NaI(Tl) detector, an 241Am radioactive source (59,53keV, 100mCi), an automatic micrometric table for the sample XZ movement and standard gamma spectrometry electronics. Two microtomography systems were used: a Fein Focus system, constituted by an X-ray tube, operated at 160kV and 0.3 to 1.1mA, a CCD camera and the movement sample system, and a Skyscan system, model 1072, with a X-ray tube operated at 100kV and 100µA, and a CCD camera. The ceramic tablets, analyzed by the gamma ray transmission technique presented results for most of the porosities data with smaller confidence intervals and inside the intervals supplied by the tablets manufacturer. The Titanium porous sample was analyzed by the two techniques, its microtomography images achieved a resolution of 17µm, obtained employing the Fein Focus system. For both techniques, this sample showed high porosity, which allows its application for this purpose. The sandstones samples were analyzed by the Skyscan system, achieving resolutions of 19µm, 11µm and 3.8µm for each sample, respectively. The resolutions of 11µm and 3.8µm were the ones that generated better 2D sections for the respective samples and, consequently, more reliable porosities. The 3.8µm resolution was the one that best quantified the pore size distribution data, showing information not shown by the 11µm resolution, showing that pores with 15 to 45µm radius are predominant, constituting 57% of the porous phase of this sample, and 1% are just constituted by pores with radius up to 3.8µm. These results show that resolution better than 3.8µm could be necessary only for specific cases.

In this contribution the issue of the stochastic reconstruction of particulatemedia from 2D photomicrographic images is addressed with particular reference to pore space connectivity. The reconstruction of porous bodies in 2D or 3D space was achieved by using simulated annealing techniques. Two methods were proposed to reconstruct a well connected pore space. The first, named PSA (Pixel-based Simulated Annealing), a pixel-movement based, three constraints were found to be necessary for the successful reconstruction of well connected pore space: the two-pointcorrelation function, the d3-4 distance transform distribution and the linealpath function for the pore phase. The second, named OSA (Object-based Simulated Annealing), only constrains the two-point correlation function. Following several researches which tried to reconstruct porous media using pixel-movement based simulated techniques, we propose a new parameter to add a microstructure descriptor, but we also propose a new technique, based in moving the microstructure grains (spheres) instead of the pixels. Both methods were applied to reconstruct reservoir rocks microstructures, and the 2D and 3D results were compared with microstructures reconstructed by truncated Gaussian methods. The PSA resulted in microstructures characterized by poor pore space connectivity, and by artificial patterns, while the OSA reconstructed microstructures with good pore space connectivity. These results indicate that the OSA method can reconstruct better microstructures than the present methods.