Placoderms appeared in the Silurian period and rapidly evolved and dominated the waters during the Devonian period. Among the earliest of the placoderms are yunnanolepids, a primitive form of antiarch from the Early Devonian of China and Vietnam. Very little work has so far been devoted to this family, and previous descriptions are based on conventional preparation methods. We can now take a closer look at a yunnanolepid specimen with the help of three dimensional modelling based on a synchrotron X-ray microtomographic scan series. The well preserved anterior ventrolateral plate exhibits an opening for the pectoral fin, clearly visible structures, and outer ornamentation. A first 3D image of the mysterious hollow called Chang’s apparatus has been constructed. Chang’s apparatus has only ever been seen in Yunnanolepididae, but never described in detail, and its function remains unknown. The trunk plate has captured settling sediment and in the inwash can be found tooth plates and scales of other gnathostomes. Among these are two well preserved anterior ventrolateral plates of young antiarchs. No ornamentation can be seen on the juveniles and their postbranchial lamina had not yet developed. / Placodermer (pansarhajar) är en grupp tidiga käkförsedda fiskar som dök upp under tidig silur. De spred sig snabbt under silur och dominerade världens vatten under devon, för att helt dö ut i slutet av devon. En av de allra tidigaste grupperna av placodermer är en grupp som kallas yunnanolepider, de var en primitiv form av antiarcher (armpansarhajar) från tidig devon i Kina och Vietnam. Man vet väldigt lite om denna grupp, och alla tidigare beskrivningar har baserats på konventionella prepareringsmetoder där man mekaniskt avlägsnat sediment som omgav fossilet. Här har ett fossil beskrivits med hjälp av röntgenbaserad mikrotomografi som sedan modellerats digitalt. Modellen visar en välbevarad bröstplåt, del av skuldergördelen, från yunnanolepiden. Denna visar en öppning med fäste för bröstfenan, interna strukturer och yttre ornamentering. Man kan här få en första syn på en intern hålighet som kallas Chang’s apparatus som aldrig tidigare har beskrivits i detalj. I sedimentet som samlats i bröstplåten kan man även se delar av andra organismer, såsom en tandplatta och fjäll. Bland dessa bitar finns två välbevarade bröstplåtar från juvenila antiarcher.

Graphite epoxy composites are being used in aerospace industry and spacecraft applications for their light weight and high strength. As a matter of fact these materials also have some disadvantages like damage which is hazardous when used in cryogenic application. Composite materials IM7/977-2, IM7/5555 and IM7/5276-1 are of interest for the aerospace industry and this research concentrates on study of microcracking, delamination and other defects in the [0/90]s composite laminates of the above materials. These materials were uni-axially tested to pre-determined stress levels and the damages in the material were recorded in the form of microcrack density at different stress levels. In this research work the use of X-Ray Microtomography has proven to be an excellent tool to characterize the crack connectivity and damage information three dimensionally. Dye penetrant technique was also used in this work to enhance the visibility of the cracks.

Diante da escassez de estudos que correlacionem a remoção do disco ou da cartilagem articular do côndilo, sobretudo, na análise de parâmetros morfométricos, o presente estudo objetivou analisar, por meio de microtomografia, alterações da estrutura e qualidade óssea em ratos (Rattus norvegicus, albinos, Wistar). Os espécimes foram divididos em três grupos experimentais e a cirurgia ocorreu, em todos os grupos, do lado direito. No grupo experimental (RDC), deu-se a remoção do disco articular e remoção da cartilagem articular do lado direito; no grupo experimental (RD), somente remoção do disco articular do lado direito; no grupo experimental (SHAM), apenas acesso cirúrgico e posterior sutura sem danos ao disco articular ou cartilagem. Os côndilos foram analisados por microtomografia e executou-se comparação entre os lados de cada grupo e entre os grupos do lado direito e esquerdo. Os parâmetros morfométricos apontaram para um declínio da estrutura e qualidade óssea, sucessivamente, em ordem crescente, no lado operado dos grupos SHAM, RD e RDC. / Considering that only few studies on the correlation between temporomandibular joint (TMJ) disk removal and conditions of the cartilage of the condyle, especially in the analysis of morphometric parameters, this study aimed to analyze changes in the bone structure and quality in rats (Rattus norvegicus, albino Wistar) with micro-computed tomography. The specimens were divided into three groups that underwent surgery in the right TMJ. In the first experimental group, surgical procedures included both disk and joint cartilage removal (DCR). In the second experimental group, only the disk was removed during surgeries (DR), whereas in the control group (SHAM) only surgical access and subsequent suture without damaging the disc or joint cartilage was performed. The condyles were analyzed by micro-computed tomography and inter-group and intra-group side (left and right) comparisons were carried out. The morphometric parameters indicated a decline in bone structure and quality successively in the groups in ascending order of TMJ surgical damage (control group, SHAM, and the two experimental groups, DR and DCR).

Understanding the controls on fluid migration in reservoir rocks is becoming evermore important within the petroleum industry as significant hydrocarbon discoveries become less frequent and more emphasis is placed on enhanced oil recovery methods. To fully understand the factors controlling fluid migration in the subsurface, pore scale information is necessary. In this study, synchrotron-based X-ray computed microtomography (CMT) is being utilized to extract physically realistic images of carbonate rock cores for the evaluation of porosity and mineralogy in the Mississippian Midale beds of the Weyburn Oilfield in southeastern Saskatchewan. Non-destructive in-situ imaging by CMT is unique as it provides a detailed and novel approach for the description of pore space geometry, while preserving connectivity and spatial variation of pore-body and pore-throat sizes. Here, three-dimensional micron to sub-micron (0.3ìm-100ìm) resolution of CMT is coupled with, and compared against, conventional laboratory-based methods (liquid and gas permeametry, mercury injection porosimetry, electrical resistivity, backscattered electron (BSE) from electron probe micro-analysis (EPMA) and transmitted light microscopy). Petrophysical and mineralogical information obtained from both CMT and conventional methods will have direct implications for understanding the petrophysical mechanisms that control fluid movement in the subsurface of the Weyburn Oilfield.<p>At Weyburn, CO2 gas is being injected into producing horizons to enhance oil recovery and permanently sequester CO2 gas. Fundamental questions exist regarding: (1) The significance of pore geometry and connectivity to the movement of CO2 and other fluids in the subsurface, (2) the nature of the interactions between CO¬2 and pore lining minerals and their impact on petrophysical properties, and (3) the distribution and mineralogy of finely disseminated silicate and carbonate minerals adjacent to pore spaces as interaction among these phases and CO2 may result in permanent sequestration of CO2. <p>The two producing horizons within the Weyburn Reservoir, the Midale Marly and Midale Vuggy units, have variable porosities and permeabilities. Porosity in the Marly unit ranges from 16% to 38% while permeability ranges from 1mD to greater than 150 mD across the field. For the Vuggy unit, porosity ranges from 8% to 21% with permeability ranging from 0.3mD to 500mD. Using CMT, pore space is critically examined to highlight the controlling factors on permeability. Digital processing of CMT data indicates that pore space in the Marly unit is dominated by intercrystalline pores having diameters of approximately 4 ìm. From here, it is noted that the pore-throat radii are approximately ½ the radii of the pore-bodies, having profound implications to current oil recovery methods. Tortuosity values from CMT are also observed to have similar values in three orthogonal directions indicating an isotropic pore space distribution within the Marly unit. Alternatively, the Vuggy unit is found to possess greater pore-body and pore-throat sizes that are heterogeneous in distribution. Based on this, permeability in the Vuggy unit is strongly dependant on pore-length scales that vary drastically between localities.

Understanding the controls on fluid migration in reservoir rocks is becoming evermore important within the petroleum industry as significant hydrocarbon discoveries become less frequent and more emphasis is placed on enhanced oil recovery methods. To fully understand the factors controlling fluid migration in the subsurface, pore scale information is necessary. In this study, synchrotron-based X-ray computed microtomography (CMT) is being utilized to extract physically realistic images of carbonate rock cores for the evaluation of porosity and mineralogy in the Mississippian Midale beds of the Weyburn Oilfield in southeastern Saskatchewan. Non-destructive in-situ imaging by CMT is unique as it provides a detailed and novel approach for the description of pore space geometry, while preserving connectivity and spatial variation of pore-body and pore-throat sizes. Here, three-dimensional micron to sub-micron (0.3ìm-100ìm) resolution of CMT is coupled with, and compared against, conventional laboratory-based methods (liquid and gas permeametry, mercury injection porosimetry, electrical resistivity, backscattered electron (BSE) from electron probe micro-analysis (EPMA) and transmitted light microscopy). Petrophysical and mineralogical information obtained from both CMT and conventional methods will have direct implications for understanding the petrophysical mechanisms that control fluid movement in the subsurface of the Weyburn Oilfield.<p>At Weyburn, CO2 gas is being injected into producing horizons to enhance oil recovery and permanently sequester CO2 gas. Fundamental questions exist regarding: (1) The significance of pore geometry and connectivity to the movement of CO2 and other fluids in the subsurface, (2) the nature of the interactions between CO¬2 and pore lining minerals and their impact on petrophysical properties, and (3) the distribution and mineralogy of finely disseminated silicate and carbonate minerals adjacent to pore spaces as interaction among these phases and CO2 may result in permanent sequestration of CO2. <p>The two producing horizons within the Weyburn Reservoir, the Midale Marly and Midale Vuggy units, have variable porosities and permeabilities. Porosity in the Marly unit ranges from 16% to 38% while permeability ranges from 1mD to greater than 150 mD across the field. For the Vuggy unit, porosity ranges from 8% to 21% with permeability ranging from 0.3mD to 500mD. Using CMT, pore space is critically examined to highlight the controlling factors on permeability. Digital processing of CMT data indicates that pore space in the Marly unit is dominated by intercrystalline pores having diameters of approximately 4 ìm. From here, it is noted that the pore-throat radii are approximately ½ the radii of the pore-bodies, having profound implications to current oil recovery methods. Tortuosity values from CMT are also observed to have similar values in three orthogonal directions indicating an isotropic pore space distribution within the Marly unit. Alternatively, the Vuggy unit is found to possess greater pore-body and pore-throat sizes that are heterogeneous in distribution. Based on this, permeability in the Vuggy unit is strongly dependant on pore-length scales that vary drastically between localities.

Bread owes its appeal to its aerated structure which directly relies on the bubbles entrained into the dough during mixing. If the bubble size distribution (BSD) in the dough can be determined at the end of mixing, then the resulting loaf quality could be predicted before bread is fully manufactured. However, non-invasively monitoring the structure of a fragile opaque soft solid such as dough is challenging. This thesis addressed the challenge by determining dough’s BSD and its evolution using ultrasound and X-ray microtomography. Using a resonant scattering model and the frequency dependence of the ultrasonic parameters measured in the dough, the change in the BSD in dough (made without yeast) with time as a result of disproportionation was determined. At 30 min after mixing, the median radius (R0) of the lognormal BSD was 6.5 microns. Converting the BSD to the radius dependence of bubble volume fraction (BVF(R)), R0V (the median radius of BVF(R)) was 66.4 microns and increased 18 % in the succeeding 90 min. In order to validate the bubble sizes determined ultrasonically, X-rays from a synchrotron source were utilized to examine dough’s microstructure. Large numbers of very small bubbles were discovered and it was apparent that lognormality did not describe the BSDs. Nevertheless, lognormal characterization of the BVF(R) was appropriate. At 30 min after mixing R0V of the BVF(R) was 32.5 microns and it increased by 20 % in the succeeding 90 min, supporting the ultrasonic quantification of bubble volume changes due to disproportionation. Changes in the mode, median and mean of the BVF(R) with time after mixing had the same trend for ultrasound and for X-ray microtomography. The time evolution of the mode of the BVF(R) obtained by ultrasound and X-ray microtomography matched very well; both increasing linearly as a function of time. Ultrasonic assessments of bubble sizes and their changes with time are very encouraging, but the ultrasonic model should use distribution functions that precisely define the empirical data, perhaps not making ‘pre-assumptions’ of lognormality for the BSD data. / February 2015

Submitted by MARIA FERNANDA LIMA Villaça-Carvalho (mfervillaca@hotmail.com) on 2016-03-29T02:07:44Z No. of bitstreams: 1 TESE MARIA FERNANDA merged.pdf: 3220002 bytes, checksum: cc48d2a3494318d6c9c1f4af8c06c37f (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-03-29T17:32:30Z (GMT) No. of bitstreams: 1 villacacarvalho_mfl_dr_sjc.pdf: 3220002 bytes, checksum: cc48d2a3494318d6c9c1f4af8c06c37f (MD5) / Made available in DSpace on 2016-03-29T17:32:30Z (GMT). No. of bitstreams: 1 villacacarvalho_mfl_dr_sjc.pdf: 3220002 bytes, checksum: cc48d2a3494318d6c9c1f4af8c06c37f (MD5) Previous issue date: 2016-01-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A Implantodontia é uma das áreas da Odontologia que mais tem evoluído nas últimas décadas. Diversos estudos são desenvolvidos na intenção de otimizar o processo de osseointegração utilizando a nanotopografia na superfície dos implantes. Atualmente o processo de anodização da superfície vem se destacando entre estas técnicas. Desta forma, o objetivo nesta pesquisa foi obter nano rugosidades e fase de anatase em implantes odontológicos de Titânio, buscando a otimização da osseointegração. Sessenta implantes foram caracterizados quanto à morfologia, por meio de microscopia de força atômica (AFM) e Microscopia Eletrônica de Varredura (MEV); quanto à composição química, por análise por detector de espectrometria por espalhamento de energia (EDS) e Espectroscopia Raman; e por fim, quanto ao potencial de corrosão, pela análise de impedância eletroquímica (EIE). A osteogênese, in vivo, foi comparada por Radiografia periapical (RP), Microtomografia Computadorizada (μTC) e teste de remoção por torque reverso; e, a análise in vitro, foi realizada por teste de citotoxicidade por MTT [(brometo de 3-4,5-dimetiltiazol-2-il)-2,5-difeniltetrazoliol]. Os implantes foram divididos em: G1 (controle); Grupo 2 (jateado); Grupo 3 (anodizado-experimental). Cada coelho recebeu um implante de cada grupo nas tíbias direita e esquerda, e cinco coelhos, foram eutanasiados 2 e 6 semanas após a cirurgia. Os implantes da tíbia direita foram submetidos à RP e à μTC; e os da tíbia esquerda, ao teste de torque reverso e análise de citotoxicidade por MTT. AFM e MEV comprovaram a presença de nano rugosidades na superfície em G3; análises de EDS e Espectroscopia Raman, demonstraram aumento da camada do filme de TiO2 e a obtenção de anatase em G3. Na RP, nenhum implante apresentou halo radiolúcido. Na μTC, G3 foi sempre superior aos demais grupos nos parâmetros observados: BV, BV/TV, Tb.Th. No teste de torque reverso, houve necessidade de maior força de remoção dos implantes anodizados. No teste por MTT, os implantes experimentais foram atóxicos células. Conclui-se que a anodização utilizada neste estudo afetou positivamente a composição química e estrutural do filme de TiO2, melhorando suas características biológicas na osseointegração. / The Implantology is one of the areas of dentistry that has most evolved in recent decades. Many studies have been developed with the intention of optimizing the osseointegration process using nanotopography on the surface of the implants. Currently the surface of the anodizing process has stood out among these techniques. Thus, the aim of this research was to obtain nano roughness and anatase phase in dental Titanium implants, seeking for the optimization of the osseointegration. Sixty implants were characterized for morphology by atomic force microscopy (AFM) and Scanning Electron Microscopy (SEM); in chemical composition, by mass spectrometry detector energy scattering (EDS) and Raman spectroscopy; and finally, as the potential for corrosion, the electrochemical impedance analysis (EIS). Osteogenesis in vivo was compared by Periapical Radiography (PR), Computed Microtomography (μTC), removal reverse torque test; and in vitro analysis, it was performed by MTT cytotoxicity assay [(bromide 3-4,5-dimethylthiazol-2-yl) -2,5-difeniltetrazoliol]. The implants were divided into G1 (control); Group 2 (sandblasted); Group 3 (anodized-experimental). Each rabbit received an implant of each group in the right and left tibias and five rabbits were euthanized 2 and 6 weeks after surgery. The implants of the right tibia underwent PR and μTC; and the left tibia, the reverse torque test and MTT cytotoxicity assay. AFM and SEM confirmed the presence of nano roughness on the surface in G3; EDS analysis and Raman spectroscopy showed increased TiO2 film layer and obtainment of anatase G3. In PR, no implant presented radiolucent halo. In μTC, G3 has always been higher than the other groups in the observed parameters: BV, BV / TV, Tb.Th. In the reverse torque test, It was required greater removal force of anodized implants. In the MTT test, the experimental implants were nontoxic to cells. It was conclude that the anodizing process used in this study positively affected the chemical and structural composition of TiO2 film, improving their biological characteristics at osseointegration.

abstract: For decades, microelectronics manufacturing has been concerned with failures related to electromigration phenomena in conductors experiencing high current densities. The influence of interconnect microstructure on device failures related to electromigration in BGA and flip chip solder interconnects has become a significant interest with reduced individual solder interconnect volumes. A survey indicates that x-ray computed micro-tomography (µXCT) is an emerging, novel means for characterizing the microstructures' role in governing electromigration failures. This work details the design and construction of a lab-scale µXCT system to characterize electromigration in the Sn-0.7Cu lead-free solder system by leveraging in situ imaging. In order to enhance the attenuation contrast observed in multi-phase material systems, a modeling approach has been developed to predict settings for the controllable imaging parameters which yield relatively high detection rates over the range of x-ray energies for which maximum attenuation contrast is expected in the polychromatic x-ray imaging system. In order to develop this predictive tool, a model has been constructed for the Bremsstrahlung spectrum of an x-ray tube, and calculations for the detector's efficiency over the relevant range of x-ray energies have been made, and the product of emitted and detected spectra has been used to calculate the effective x-ray imaging spectrum. An approach has also been established for filtering `zinger' noise in x-ray radiographs, which has proven problematic at high x-ray energies used for solder imaging. The performance of this filter has been compared with a known existing method and the results indicate a significant increase in the accuracy of zinger filtered radiographs. The obtained results indicate the conception of a powerful means for the study of failure causing processes in solder systems used as interconnects in microelectronic packaging devices. These results include the volumetric quantification of parameters which are indicative of both electromigration tolerance of solders and the dominant mechanisms for atomic migration in response to current stressing. This work is aimed to further the community's understanding of failure-causing electromigration processes in industrially relevant material systems for microelectronic interconnect applications and to advance the capability of available characterization techniques for their interrogation. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2015

Orientador: Mário Tanomaru Filho / Banca: Idomeo Bonetti Filho / Banca: Yara Teresinha Corrêa Silva Sousa / Resumo: Materiais endodônticos devem apresentar propriedades físico-químicas segundo ISO e ADA. Novas metodologias empregando Microtomografia Computadorizada (Micro-CT) podem ser utilizadas. Este estudo foi dividido em quatro capítulos: Capítulo 1: avaliou MTA Angelus (MTA), Biodentine (BIO) e óxido de zinco e eugenol (OZE) utilizando testes convencionais e com Micro-CT. Solubilidade e alteração dimensional basearam-se em Carvalho-Junior et al. (2007). Capacidade de preenchimento e alteração volumétrica foram avaliadas por Micro-CT. Foram realizados os testes ANOVA e Tukey com 5% de significância. BIO e MTA apresentaram maior estabilidade dimensional. OZE e BIO mostraram maior capacidade de preenchimento. Aos 7 dias a solubilidade foi maior para BIO e a alteração volumétrica foi semelhante para os materiais. Aos 30 dias, a solubilidade foi semelhante para os materiais, porém a alteração volumétrica foi maior para BIO que MTA. BIO apresenta capacidade de preenchimento, porém maior alteração volumétrica. Micro-CT pode complementar testes convencionais. Capítulo 2: Nova técnica para avaliação do escoamento foi proposta com Micro-CT. MTA, OZE e BIO foram avaliados segundo ISO 6876/2002 e pela técnica proposta. Placa de vidro com cavidade central e 4 canaletas foi confeccionada. Cada material foi colocado sobre a cavidade central e nova placa de vidro posicionada. O conjunto foi escaneado por meio de Micro-CT. O escoamento foi calculado pela mensuração linear (mm) em cada canaleta. O pre... (Resumo completo, clicar acesso eletrônico abaixo) / Abtract: Endodontic materials have to present physicochemical properties according to ISO and ADA. New methodologies using microcomputed tomography (Micro-CT) can be used. This study was divided into four chapters: Chapter 1: evaluated MTA Angelus (MTA), Biodentine (BIO) and zinc oxide and eugenol (ZOE) using conventional and Micro-CT tests. Solubility and dimensional stability based on Carvalho-Junior et al. (2007). Filling ability and volumetric change were evaluated by Micro-CT. ANOVA and Tukey test with 5% significance were performed. BIO and MTA had greater dimensional stability. ZOE and BIO showed greater filling ability. At 7 days solubility was greater for BIO and volumetric change was similar for materials. At 30 days, the solubility was similar to the materials, but the volumetric change was greater for BIO than MTA. BIO presents filling ability, but higher volumetric change. Micro-CT can complement conventional tests. Chapter 2: New technique to assess the flow was proposed using Micro-CT. MTA, ZOE and BIO were evaluated according to ISO 6876/2002 and the proposal method. A glass device with a central cavity and four grooves was made. Each material was placed over the central cavity and a new glass device was positioned. The set was scanned by Micro-CT. The flow was calculated by linear measurement (mm) on each groove. The central volumetric filling (CVF) in mm³ was calculated in the central cavity and the lateral volumetric filling (LVF) was measured by the average filling in the side grooves up to 2 mm. The results were submitted to ANOVA and Tukey, with 5% level. ZOE was the material with higher flow by ISO methodology. Using Micro-CT, MTA and ZOE showed higher linear flow. CVF was similar to materials. However, LVF was higher to Biodentine than ZOE. It is concluded that MTA and ZOE have better linear... (Complete abstract electronic access below) / Mestre

Diante da escassez de estudos que correlacionem a remoção do disco ou da cartilagem articular do côndilo, sobretudo, na análise de parâmetros morfométricos, o presente estudo objetivou analisar, por meio de microtomografia, alterações da estrutura e qualidade óssea em ratos (Rattus norvegicus, albinos, Wistar). Os espécimes foram divididos em três grupos experimentais e a cirurgia ocorreu, em todos os grupos, do lado direito. No grupo experimental (RDC), deu-se a remoção do disco articular e remoção da cartilagem articular do lado direito; no grupo experimental (RD), somente remoção do disco articular do lado direito; no grupo experimental (SHAM), apenas acesso cirúrgico e posterior sutura sem danos ao disco articular ou cartilagem. Os côndilos foram analisados por microtomografia e executou-se comparação entre os lados de cada grupo e entre os grupos do lado direito e esquerdo. Os parâmetros morfométricos apontaram para um declínio da estrutura e qualidade óssea, sucessivamente, em ordem crescente, no lado operado dos grupos SHAM, RD e RDC. / Considering that only few studies on the correlation between temporomandibular joint (TMJ) disk removal and conditions of the cartilage of the condyle, especially in the analysis of morphometric parameters, this study aimed to analyze changes in the bone structure and quality in rats (Rattus norvegicus, albino Wistar) with micro-computed tomography. The specimens were divided into three groups that underwent surgery in the right TMJ. In the first experimental group, surgical procedures included both disk and joint cartilage removal (DCR). In the second experimental group, only the disk was removed during surgeries (DR), whereas in the control group (SHAM) only surgical access and subsequent suture without damaging the disc or joint cartilage was performed. The condyles were analyzed by micro-computed tomography and inter-group and intra-group side (left and right) comparisons were carried out. The morphometric parameters indicated a decline in bone structure and quality successively in the groups in ascending order of TMJ surgical damage (control group, SHAM, and the two experimental groups, DR and DCR).