The project main purpose is to design a prototypeof a leaky-wave antenna (LWA) which will serve as a basisto future manufacturing of a more advanced product withpotential use for an imaging radar system. The antenna consistsof Goubau line corrugations with rectangular radiation patches.Both configurations with longitudinal symmetric and glidesymmetric corrugations have been analyzed, paying specialattention to their dispersion diagrams. A parametric study ofthe dimensions of the structure has been conducted as well.Radiation patches have been added with different offsetingsbetween each other, in order to study the effect of the separationbetween patches to the radiation pattern. The frequencybeam scanning characteristic of the antenna is also shown.This antenna operates at a center frequency of 9.4 GHz, withan efficiency of 80 %. It scans over an approximate angle widthfrom -50 to 50◦ in a frequency range from 8.5 to 10.2 GHz.It has been modeled using CST Microwave Studio and Matlab. / Det huvudsakliga målet för projektet är att designa en prototyp av en läckvågsantenn (LWA) som ska verka som en grund för framtida tillverkning av mer avancerade produkter, med potentiell användning för radarsystem för bildtagning. Antennen består av en Goubau linje veckning med rektangulära strålningsflikar. Båda konfigurationerna med longitudinell symmetri och glid symmetri har analyserats. Förutom detta har en parameterstudie av dimensionerna av strukturen utförts. Strålningsflikar har blivit tillagda med olika förskjutningar mellan varandra, för att studera effekten av separationen mellan flikarna och strålningsmönstret. Egenskaperna hos antennens frekvensberoende skanning visas också. Denna antenn fungerar vid en centerfrekvens på 9.4 GHz, med en effektivitet på 80%. Den skannar över en ungefärlig vinkel från -50 till 50◦ över ett frekvensspann från 8.5 till 10.2 GHz. Detta har modellerats med CST Microwave Studio och Matlab. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

In recent years, a new field of study has arisen around theapplication of the so-called higher symmetries to structures that werealready thought to be completely studied and with no room forimprovement in terms of benefits.There are two types of higher symmetries, named glide and twistsymmetries. The objective of this Master thesis is the study of theeffects coming from the application of the glide symmetry on aprinted filter in microstrip technology and its comparison with afilter with conventional reflective symmetry.The filter was adapted to the glide characteristics and we provide itsbehavior from different points of view with the purpose of reachinga better understanding of the consequences of applying the glidesymmetry on this type of printed filters.Three prototypes were manufactured and measured to validate thesimulated results. / Under senare år har ett nytt forskningsfält uppkommit genom applikationen av högre symmetrier till strukturer som redan studerats extensivt. Det finns två typer av högre symmetrier och dessa kallas glid- och vridsymmetrier. Målet med detta masterexamensarbete är att studera effekten som kommer från applikationen av glidsymmetri på ett filter, implementerat i mikrostripsteknik. Jämförelse med filtret med enbart reflektionssymmetri görs också. Glidsymmetri har introducerats i filtret och vi undersöker filtrets beteende från en rad olika synvinklar för att uppnå en bättre förståelse för konsekvenserna av glidsymmetri för den här typen av tryckta (”printed”) filter. Flera prototyper har tillverkats och mätts för att validera de simulerade resultaten.

There are more connected wireless devices than everbefore and with the rise of new smart systems such as self-drivingcars and smart cities new antenna solutions for transmittingsignals are needed. One important part of these systems is thefilters which filter out all the unwanted signals. In this report,we present a solution for manufacturing such a filter with apassband from 26-29 GHz and a stopband from 29-60 GHz usinga fully metallic glide-symmetric structure. Ideas of combiningmultiple unit cell designs to achieve wider stopbands and higherattenuation are explored using dispersion engineering wherethe advantages and the disadvantages of using this method arepresented. Furthermore, ways of combining the filter to standardconnections using a coaxial cable to waveguide transition areproposed and designed. The usage of multiple unit cell designsis proven to be a solution for achieving wider stopbands withminimum coupling between modes. / Det finns fler trådlösa enheter uppkoppladeän n°agonsin tidigare och med ökningen av nya smarta systemsom självkörande bilar och smarta städer finns ett behov av nyaantennlösningar för överföring av information. En viktig del avdessa system är filtren som filtrerar bort alla oönskade signaler.I denna rapport presenterar vi en lösning för att konstrueraett sådant filter med ett passband från 26-29 GHz och ettstoppband från 29-60 GHz med en helt metallisk glidsymmetriskstruktur. Id´eer att kombinera flera enhetscellsdesigner för attuppnå bredare stoppband och högre attenuering undersöks medhjälp av dispersionsteknik, där fördelarna och nackdelarna medatt använda denna metod presenteras. Dessutom föreslås ochutformas sätt att kombinera filtret till standardanslutningar meden koaxialkabel till vågledarövergång. Användningen av fleraenhetscell designer visar sig vara en lösning för att skapa bredastoppband med minimal koppling mellan ”modes”. / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm

Submitted by PPG Odontologia (odontologia-pg@pucrs.br) on 2018-12-12T18:58:35Z No. of bitstreams: 1 RAFAEL_CHIES_HARTMANN_TESE.pdf: 1515467 bytes, checksum: 0787dc0b8180f2af60c74c918444dab7 (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-12-14T13:33:17Z (GMT) No. of bitstreams: 1 RAFAEL_CHIES_HARTMANN_TESE.pdf: 1515467 bytes, checksum: 0787dc0b8180f2af60c74c918444dab7 (MD5) / Made available in DSpace on 2018-12-14T16:01:26Z (GMT). No. of bitstreams: 1 RAFAEL_CHIES_HARTMANN_TESE.pdf: 1515467 bytes, checksum: 0787dc0b8180f2af60c74c918444dab7 (MD5) Previous issue date: 2018-11-12 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The great majority of the roots present curvatures and the knowledge of these curves allows the clinician a better choice for endodontic therapy. Therefore, it is necessary to use methods that can measure these curvatures with good accuracy levels. The preparation of a glide path prior to root canal instrumentation is widely suggested because can avoid possible operative errors, such as loss of centralization and apical transportation, especially in curved root canals. There is no consensus concerning the methods that can be used to measure radicular curvatures, nor regarding the efficacy of glide path. The present investigation has the objective of performing two systematic reviews in order to answer the following questions: 1- What are the methods, described in the literature, used to measure the angles and other characteristics of the curvatures of the root canals? 2- The glide path is able to reduce the apical transportation and the loss of centralization of the endodontic preparation? Also, how does the glide path - manual or engine-driven - result in minor operative errors? Methods: Using the appropriate terms for each review, electronic searches were performed on six databases: PubMed, PubMed Central (PMC), Embase, Scopus, EBSCO Dentistry & Oral Sciences Source (DOSS) and Virtual Health Library (VHL). We used studies published in English or in any language with Latin alphabet. There was no time limit for publications. In addition, in the second review, the included studies, the risk of biases was analyzed. Results: In review 1, about the methods of measurement of curvatures, 6,336 studies were obtained and of these, 31 articles that described innovative methods. Eleven studies described the methods used to measure only the angle of the radicular curvatures, for which they used 2D images. 13 studies also used 2D images, however, in addition to the angles, evaluated other features of the root canal curvatures (position, length, direction, height and shape). In addition, seven studies evaluated curvatures using 3D methods. In review 2, regarding glide path, 2,146 articles were obtained, and 18 studies fulfilled the inclusion criteria, composing the final analysis. 9 studies evaluated the glide path per se and 11 evaluated the impact of glide path on final engine-driven endodontic preparation. Conclusion: Revision 1 suggested that most methods for root canal curvature measurement have potential clinical applications; however, there is a lack of consensus on the ideal technique. In addition to the angle, other features, such as radius and position of curvature, need to be measured and should be considered when evaluating root canal curvature in both clinical and research purposes. Revision 2 revealed that engine-driven confection of glide path, when compared to manual, presents similar or better results of apical transportation and maintenance of root canal centralization. It was also observed that the preparation of glide path, prior to endodontic preparation, is associated with similar results or with a reduction of the apical transportation and the maintenance of the preparation centralization. It was also observed that deviations occur in all situations. / A grande maioria dos condutos apresenta curvaturas e o conhecimento destas curvaturas permite ao cl?nico uma melhor escolha da terap?utica endod?ntica. Para tanto, faz-se necess?rio o emprego de m?todos que possam medir essas curvaturas com bons n?veis de acur?cia. A confec??o de um glide path pr?vio ? instrumenta??o dos canais radiculares ? amplamente sugerida, pois pode evitar poss?veis erros operat?rios, tais como a perda de centraliza??o do preparo e o transporte apical, especialmente em canais radiculares curvos. Como n?o h? consenso quanto aos m?todos que podem ser utilizados na medi??o das curvaturas radiculares, tampouco referente a efic?cia do glide path, a presente investiga??o tem o objetivo de realizar duas revis?es sistem?ticas, a fim de responder ?s seguintes quest?es: 1- Quais s?o os m?todos, descritos na literatura, empregados na mensura??o dos ?ngulos e demais caracter?sticas das curvaturas dos canais radiculares? 2- O glide path ? capaz de reduzir o transporte apical e a perda de centraliza??o do preparo endod?ntico? Al?m disso, qual a forma de confec??o do glide path ? manual ou motorizada ? resulta em menores erros operat?rios? M?todos: Utilizando os termos apropriados para cada revis?o, foram realizadas buscas eletr?nicas em seis bases de dados: PubMed, PubMed Central (PMC), Embase, Scopus, EBSCO Dentistry & Oral Sciences Source (DOSS) e Virtual Health Library (VHL). Foram utilizados estudos publicados em ingl?s ou em qualquer idioma com alfabeto latino n?o houve qualquer limite temporal para as publica??es. Al?m disso, na segunda revis?o, os estudos inclu?dos tiveram o risco de vieses analisado. Resultados: Na revis?o 1, acerca dos m?todos de mensura??o das curvaturas, foram obtidos 6.346 estudos e destes, restaram 31 artigos que descreviam m?todos inovadores. Onze estudos foram descritos a fim de mensurar apenas o ?ngulo das curvaturas radiculares, para isso utilizaram 9 imagens em 2D. 13 estudos utilizaram tamb?m imagens em 2D, entretanto, al?m dos ?ngulos avaliaram outras caracter?sticas das curvaturas dos canais radiculares (posi??o, comprimento, dire??o, altura e forma). Al?m disso, sete estudos avaliaram as curvaturas atrav?s de m?todos em 3D. J? na revis?o 2, a respeito do glide path, obteve-se 2.146 artigos, sendo que 18 estudos preencheram os crit?rios de inclus?o, compondo a an?lise final. 9 pesquisas avaliaram a confec??o do glide path per se e 11 avaliaram a repercuss?o do glide path no preparo endod?ntico motorizado final. Conclus?o: a revis?o 1 sugeriu que a maioria dos m?todos de mensura??o de curvaturas dos canais radiculares tem potenciais aplica??es cl?nicas, no entanto, h? uma falta de consenso sobre a t?cnica ideal. Al?m do ?ngulo, outros fatores, como raio e posi??o da curvatura, precisam ser mensurados e devem ser levados em considera??o ao se avaliar a curvatura do canal radicular tanto em tratamentos cl?nicos como em ambientes de pesquisa. J? a revis?o 2 revelou que a confec??o motorizada, quando comparada com a confec??o manual, do glide path apresenta resultados similares ou melhores de transporte apical e manuten??o da centraliza??o do canal radicular. Observou-se, tamb?m, que a confec??o do glide path, previamente ao preparo endod?ntico, est? associada com resultados similares ou com a redu??o do transporte apical e a manuten??o da centraliza??o do preparo. Tamb?m foi observado que ocorrem desvios em todas as situa??es.

The text-guided diffusion model GLIDE (Guided Language to Image Diffusion for Generation and Editing) is the state of the art in text-to-image generative artificial intelligence (AI). GLIDE has rich representations, but medical applications of this model have not been systematically explored. If GLIDE had useful medical knowledge, it could be used for medical image analysis tasks, a domain in which AI systems are still highly engineered towards a single use-case. Here we show that the publicly available GLIDE model has reasonably strong representations of key topics in cancer research and oncology, in particular the general style of histopathology images and multiple facets of diseases, pathological processes and laboratory assays. However, GLIDE seems to lack useful representations of the style and content of radiology data. Our findings demonstrate that domain-agnostic generative AI models can learn relevant medical concepts without explicit training. Thus, GLIDE and similar models might be useful for medical image processing tasks in the future - particularly with additional domain-specific fine-tuning.

Materials intended for disposal of spent nuclear fuel require a particular combination of physical and chemical properties. The driving forces and mechanisms underlying the material’s behavior must be scientifically understood in order to enable modeling at the relevant time- and length-scales. The processes that determine the mechanical behavior of copper canisters and iron inserts, as well as the evolution of their mechanical properties, are strongly dependent on the properties of various defects in the bulk copper and iron alloys. The first part of the present thesis deals with precipitation in the cast iron insert. A nodular cast iron insert will be used as the inner container of the spent nuclear fuel. Precipitation is investigated by computing effective interaction energies for point defect pairs (solute–solute and vacancy–solute) in bcc iron using first-principles calculations. The main considered impurities in the iron matrix include 3sp (Si, P, S) and 3d (Cr, Mn, Ni, Cu) solute elements. By computing interaction energies possibility of formation of different second phase particles such as late blooming phases (LBPs) in the cast iron insert is evaluated. The second part is devoted to the fundamentals of dislocations and their role in plastic deformation of metals. Deformation of single-crystal copper under high strain rates is simulated by employing dislocation dynamics (DD) method to examine the effect of strain rate on mechanical properties as well as dislocation microstructure development. Creep deformation of copper canister at low temperatures is studied. The copper canister will be used in the long-term storage of spent nuclear fuel as the outer shell of the waste package to provide corrosion protection. A glide rate is derived based on the assumption that at low temperatures it is controlled by the climb rate of jogs on the dislocations. Using DD simulation creep deformation of copper at low temperatures is modeled by taking glide but not climb into account. Moreover, effective stresses acting on dislocations are computed using the data extracted from DD simulations. / <p>QC 20170428</p>

Endodontic retreatments are time-consuming and difficult to perform. Removing the root canal filling material of the original treatment with maximum efficiency and safety is a complex task that requires a good technique, patience and perseverance. This filling material is often contaminated and prevents access to areas of the canal harboring bacteria and remnants of necrotic tissue, especially in the isthmus region and in dentinal tubules. The aim of this study was to use micro-computed tomography to evaluate two protocols for the removal of root canal filling material from curved root canals of the mesial roots of mandibular molars using a reciprocating instrument followed by two different rotary instruments manufactured with different nickel-titanium alloys. The reduction in the volume of the filling material inside the root canals was evaluated. Assessments were also made of the influence of the glide path extension on root canal obturation, the extrusion of filling material after the use of the reciprocating instrument, the volume of filling material after retreatment and its presence in isthmus areas. In addition, the use of a solvent and the agitation of a 2% sodium hypochlorite solution using either passive ultrasonic irrigation (PUI) or a plastic instrument in reciprocating motion were evaluated. A total of 40 mesial roots of mandibular molars with a mean curvature of 25 degrees were selected. The teeth were radiographed digitally in the buccolingual and mesiodistal directions, with a digital Xray system (Schick CDR; Schick Technologies, Long Island, NY), using an exposure time of 0.16 s. This was done in order to select the teeth and then compose two groups with similar characteristics to ensure their anatomic homogeneity. Group homogeneity in terms of anatomy, root canal length, curvature angle, and Vertucci classification type II and IV were confirmed and showed that the study groups were well balanced. Two groups were defined according to the retreatment protocol adopted, namely RHPui (Reciproc + Hyflex + PUI) and RMEasy (Reciproc + Mtwo + EasyClean). The teeth were instrumented with the Reciproc R25 instrument and filled using the single-cone technique and AHPlus cement. Prior to the use of this instrument, canal patency was achieved by creating a glide path with PathFile instruments, throughout the entire extension of the canal in Group RHPui, and up to 1 mm short of the total canal length in Group RMEasy. In both groups, the original filling material was removed with the Reciproc R25 instrument. Xylene was used as a solvent in Group RHPui up to the middle third, but not in the apical area, in the later steps of instrumentation with Reciproc R25. In Group RHPui, the Hyflex 40.04 instrument, made with a CM nickeltitanium alloy, was used. After that, xylene solvent was applied for one minute in the pulp chamber, followed by passive ultrasonic irrigation (PUI) with 2% sodium hypochlorite using an irrisonic instrument, applied up to 2 mm short of the working length. In Group RMEasy, the Mtwo 40.04 instrument, made with a conventional nickeltitanium alloy, was used. Xylene solvent was also used in the pulp chamber for one minute, followed by application of a 2% sodium hypochlorite solution agitated mechanically with an EasyClean plastic instrument in reciprocating motion up to the full working length. The two groups were re-obturated using the warm vertical condensation technique, with a gutta-percha cone corresponding to the final instrument, and with AHPus cement. Micro-CT scans were performed after each procedure to evaluate the volume of the remaining material, the extrusion after the use of the reciprocating instruments, the final volume of the obturation at the end of the retreatment and the filling material volume in the isthmus area, both after the original obturation and after re-obturation. The results showed that the initial filling was significantly closer to the apical foramen in Group RHPui than in Group RMEasy, after the initial treatment. After performing the retreatment protocols, the complete removal of filling material from inside the root canals was not achieved in either study group, with no statistically significant difference (P > 0.05) between groups regarding this variable. In the intra-group evaluation, a statistically significant difference (P < 0.05) was found between the procedural steps regarding the reduction in filling material volume, both in the total canal length and at its different levels, except for the middle third after HyFlex, the cervical third after Mtwo, and the middle third after EasyClean. The volume of the final filling material was significantly higher (P < 0.05) than the volume of the original filling material in both study groups. The volume of filling material in the isthmus region was significantly higher after re-obturation in both groups (P < 0.05), and this increase was greater in the RMEasy Group. There was no statistically significant difference (P > 0.05) between groups regarding the total amount of time expended in the removal of filling material (P > 0.05), namely 209.40 s for the RHPui Group and 227.40 s for the RMEasy Group. There was also no statistically significant difference (P > 0.05) between groups regarding the volume of extruded filling material, namely 0.0258 mm3 (0 0.954) in the RHPui Group and 0.0037 mm3 (0 0.565) in the RMEasy Group. The Shapiro-Wilks, Mann-Whitney, Wilcoxon, Friedman and Dunn tests were used in the data analysis. / Os retratamentos endodônticos demandam tempo e são difíceis de serem executados. Remover o material de obturação do tratamento original com a máxima eficiência e segurança é uma tarefa complexa que necessita de técnica, paciência e perseverança. Esse material de obturação muitas vezes está contaminado, e impede o acesso às áreas do canal onde permaneceram restos de tecido necrótico e microrganismos, especialmente na região do istmo e nos túbulos dentinários. O objetivo deste trabalho foi avaliar, por meio da microtomografia computadorizada, dois protocolos de desobturação de canais radiculares curvos de raízes mesiais de molares inferiores utilizando um instrumento reciprocante seguido de dois diferentes instrumentos rotatórios fabricados com diferentes ligas metálicas de níquel-titânio. Além da redução dos volumes de material obturador no interior dos canais, foram avaliados a influência do comprimento da patência do canal radicular (glide path) na obturação, extrusão de material obturador após o uso do instrumento reciprocante Reciproc R25, o volume do material de obturação após o retratamento e a presença deste em áreas de istmo. Também foi avaliado o uso de um solvente seguido da agitação do hipoclorito de sódio a 2% com ultrassom (PUI) e com um instrumento plástico acionado em movimento reciprocante. Foram selecionadas 40 raízes mesiais de molares inferiores com curvatura média de 25 graus que foram divididos em dois grupos de forma homogênea quanto ao comprimento, à curvatura e à anatomia (classes II e IV de acordo com a classificação de Vertucci) dos canais radiculares. Os dentes foram instrumentados com o instrumento Reciproc R25 e obturados com a técnica do cone único e com cimento AHPlus. Previamente ao uso do instrumento Reciproc R25, obteve-se a patência inicial do canal, ou seja, criou-se um glide path, com os instrumentos PathFile em toda a extensão do canal no Grupo RHPui e 1 mm aquém do comprimento total do canal no Grupo RMEasy. Os dois grupos foram definidos de acordo com o protocolo de retratamento adotado, a saber, RHPui (Reciproc + Hyflex + PUI) e RMEasy (Reciproc + Mtwo + EasyClean). Nos dois grupos, a remoção do material obturador original foi realizada com o instrumento Reciproc R25, sendo que no grupo RHPui foi utilizado o solvente xilol até a proximidade do terço médio, não sendo utilizado solvente no terço apical. No Grupo RHPui, utilizouse, então, o instrumento Hyflex 40.04 feito com liga de niquel-titânio CM (control memory ou de memória controlada) e, por último, utilizou-se o solvente xilol por um minuto na câmara pulpar, seguido de irrigação ultrassônica passiva (PUI) com solução de hipoclorito de sódio a 2% utilizando o instrumento Irrisonic, até o limite de 2 mm aquém do comprimento de trabalho. No Grupo RMEasy, foi utilizado o instrumento Mtwo 40.04 fabricado com liga de níquel-titânio convencional e, a seguir, também se utilizou o solvente xilol por um minuto na câmara pulpar seguido de uma agitação mecânica do hipoclorito de sódio a 2% com o instrumento plástico EasyClean em movimento reciprocante até o limite do comprimento total de trabalho. Os dois grupos foram re-obturados com a técnica de condensação vertical aquecida com cone de guta-percha correspondente ao instrumento final e com cimento AHPus. Foram realizadas microtomografias após cada procedimento para avaliar o volume de material remanescente, a extrusão após o uso dos instrumentos reciprocantes, o volume final da obturação ao final do retratamento e o volume na área de istmo, tanto após a obturação original quanto após a re-obturação. Os resultados obtidos mostraram que, no tratamento inicial, a patência do canal (ou glidepath) realizado com instrumentos Pathfile previamente ao uso dos instrumentos Reciproc R25 possibilitou que a obturação dos canais atingisse um limite significativamente (P < 0,05) mais próximo ao forame apical no grupo RHPui, onde o glidepath foi realizado em toda a extensão do canal. Em relação aos diferentes protocolos de retratamento, não houve remoção completa do material obturador do interior dos canais nos dois grupos estudados em todos os níveis avaliados, sem diferença estatisticamente significativa (P > 0,05) entre os grupos com relação a essa variável. Na avaliação intragrupo, houve uma diferença estatisticamente significativa (P < 0,05) entre os passos do procedimento em relação à redução do volume de material obturador, tanto na extensão total do canal, quanto nos seus diferentes níveis, com exceção do terço médio após o Hyflex, no terço cervical após o Mtwo e no terço médio após o EasyClean. O volume do material obturador final foi significativamente maior (P < 0,05) do que o volume do material obturador original, nos dois grupos estudados. O volume de material obturador na região do istmo foi significativamente maior (P < 0,05) após a re-obturação nos dois grupos, sendo significativamente maior (P < 0,05) no grupo RMEasy do que no grupo RHPui. Não houve diferença estatística (P > 0,05) entre os grupos com relação ao tempo total despendido na remoção do material obturador (P > 0,05), sendo 209,40 s para o Grupo RHPui e 227,40 s para o Grupo RMEasy. Não houve diferença estatística (P > 0,05) entre os grupos com relação ao volume da extrusão de material obturador, sendo 0,0258 mm3 (0 0,954) no Grupo RHPui e 0,0037 mm3 (0 0,565) no Grupo RMEasy. Os testes de Shapiro-Wilks, Mann- Whitney, Wilcoxon, Friedman e Dunn foram utilizados na análise dos dados.

Endodontic retreatments are time-consuming and difficult to perform. Removing the root canal filling material of the original treatment with maximum efficiency and safety is a complex task that requires a good technique, patience and perseverance. This filling material is often contaminated and prevents access to areas of the canal harboring bacteria and remnants of necrotic tissue, especially in the isthmus region and in dentinal tubules. The aim of this study was to use micro-computed tomography to evaluate two protocols for the removal of root canal filling material from curved root canals of the mesial roots of mandibular molars using a reciprocating instrument followed by two different rotary instruments manufactured with different nickel-titanium alloys. The reduction in the volume of the filling material inside the root canals was evaluated. Assessments were also made of the influence of the glide path extension on root canal obturation, the extrusion of filling material after the use of the reciprocating instrument, the volume of filling material after retreatment and its presence in isthmus areas. In addition, the use of a solvent and the agitation of a 2% sodium hypochlorite solution using either passive ultrasonic irrigation (PUI) or a plastic instrument in reciprocating motion were evaluated. A total of 40 mesial roots of mandibular molars with a mean curvature of 25 degrees were selected. The teeth were radiographed digitally in the buccolingual and mesiodistal directions, with a digital Xray system (Schick CDR; Schick Technologies, Long Island, NY), using an exposure time of 0.16 s. This was done in order to select the teeth and then compose two groups with similar characteristics to ensure their anatomic homogeneity. Group homogeneity in terms of anatomy, root canal length, curvature angle, and Vertucci classification type II and IV were confirmed and showed that the study groups were well balanced. Two groups were defined according to the retreatment protocol adopted, namely RHPui (Reciproc + Hyflex + PUI) and RMEasy (Reciproc + Mtwo + EasyClean). The teeth were instrumented with the Reciproc R25 instrument and filled using the single-cone technique and AHPlus cement. Prior to the use of this instrument, canal patency was achieved by creating a glide path with PathFile instruments, throughout the entire extension of the canal in Group RHPui, and up to 1 mm short of the total canal length in Group RMEasy. In both groups, the original filling material was removed with the Reciproc R25 instrument. Xylene was used as a solvent in Group RHPui up to the middle third, but not in the apical area, in the later steps of instrumentation with Reciproc R25. In Group RHPui, the Hyflex 40.04 instrument, made with a CM nickeltitanium alloy, was used. After that, xylene solvent was applied for one minute in the pulp chamber, followed by passive ultrasonic irrigation (PUI) with 2% sodium hypochlorite using an irrisonic instrument, applied up to 2 mm short of the working length. In Group RMEasy, the Mtwo 40.04 instrument, made with a conventional nickeltitanium alloy, was used. Xylene solvent was also used in the pulp chamber for one minute, followed by application of a 2% sodium hypochlorite solution agitated mechanically with an EasyClean plastic instrument in reciprocating motion up to the full working length. The two groups were re-obturated using the warm vertical condensation technique, with a gutta-percha cone corresponding to the final instrument, and with AHPus cement. Micro-CT scans were performed after each procedure to evaluate the volume of the remaining material, the extrusion after the use of the reciprocating instruments, the final volume of the obturation at the end of the retreatment and the filling material volume in the isthmus area, both after the original obturation and after re-obturation. The results showed that the initial filling was significantly closer to the apical foramen in Group RHPui than in Group RMEasy, after the initial treatment. After performing the retreatment protocols, the complete removal of filling material from inside the root canals was not achieved in either study group, with no statistically significant difference (P > 0.05) between groups regarding this variable. In the intra-group evaluation, a statistically significant difference (P < 0.05) was found between the procedural steps regarding the reduction in filling material volume, both in the total canal length and at its different levels, except for the middle third after HyFlex, the cervical third after Mtwo, and the middle third after EasyClean. The volume of the final filling material was significantly higher (P < 0.05) than the volume of the original filling material in both study groups. The volume of filling material in the isthmus region was significantly higher after re-obturation in both groups (P < 0.05), and this increase was greater in the RMEasy Group. There was no statistically significant difference (P > 0.05) between groups regarding the total amount of time expended in the removal of filling material (P > 0.05), namely 209.40 s for the RHPui Group and 227.40 s for the RMEasy Group. There was also no statistically significant difference (P > 0.05) between groups regarding the volume of extruded filling material, namely 0.0258 mm3 (0 0.954) in the RHPui Group and 0.0037 mm3 (0 0.565) in the RMEasy Group. The Shapiro-Wilks, Mann-Whitney, Wilcoxon, Friedman and Dunn tests were used in the data analysis. / Os retratamentos endodônticos demandam tempo e são difíceis de serem executados. Remover o material de obturação do tratamento original com a máxima eficiência e segurança é uma tarefa complexa que necessita de técnica, paciência e perseverança. Esse material de obturação muitas vezes está contaminado, e impede o acesso às áreas do canal onde permaneceram restos de tecido necrótico e microrganismos, especialmente na região do istmo e nos túbulos dentinários. O objetivo deste trabalho foi avaliar, por meio da microtomografia computadorizada, dois protocolos de desobturação de canais radiculares curvos de raízes mesiais de molares inferiores utilizando um instrumento reciprocante seguido de dois diferentes instrumentos rotatórios fabricados com diferentes ligas metálicas de níquel-titânio. Além da redução dos volumes de material obturador no interior dos canais, foram avaliados a influência do comprimento da patência do canal radicular (glide path) na obturação, extrusão de material obturador após o uso do instrumento reciprocante Reciproc R25, o volume do material de obturação após o retratamento e a presença deste em áreas de istmo. Também foi avaliado o uso de um solvente seguido da agitação do hipoclorito de sódio a 2% com ultrassom (PUI) e com um instrumento plástico acionado em movimento reciprocante. Foram selecionadas 40 raízes mesiais de molares inferiores com curvatura média de 25 graus que foram divididos em dois grupos de forma homogênea quanto ao comprimento, à curvatura e à anatomia (classes II e IV de acordo com a classificação de Vertucci) dos canais radiculares. Os dentes foram instrumentados com o instrumento Reciproc R25 e obturados com a técnica do cone único e com cimento AHPlus. Previamente ao uso do instrumento Reciproc R25, obteve-se a patência inicial do canal, ou seja, criou-se um glide path, com os instrumentos PathFile em toda a extensão do canal no Grupo RHPui e 1 mm aquém do comprimento total do canal no Grupo RMEasy. Os dois grupos foram definidos de acordo com o protocolo de retratamento adotado, a saber, RHPui (Reciproc + Hyflex + PUI) e RMEasy (Reciproc + Mtwo + EasyClean). Nos dois grupos, a remoção do material obturador original foi realizada com o instrumento Reciproc R25, sendo que no grupo RHPui foi utilizado o solvente xilol até a proximidade do terço médio, não sendo utilizado solvente no terço apical. No Grupo RHPui, utilizouse, então, o instrumento Hyflex 40.04 feito com liga de niquel-titânio CM (control memory ou de memória controlada) e, por último, utilizou-se o solvente xilol por um minuto na câmara pulpar, seguido de irrigação ultrassônica passiva (PUI) com solução de hipoclorito de sódio a 2% utilizando o instrumento Irrisonic, até o limite de 2 mm aquém do comprimento de trabalho. No Grupo RMEasy, foi utilizado o instrumento Mtwo 40.04 fabricado com liga de níquel-titânio convencional e, a seguir, também se utilizou o solvente xilol por um minuto na câmara pulpar seguido de uma agitação mecânica do hipoclorito de sódio a 2% com o instrumento plástico EasyClean em movimento reciprocante até o limite do comprimento total de trabalho. Os dois grupos foram re-obturados com a técnica de condensação vertical aquecida com cone de guta-percha correspondente ao instrumento final e com cimento AHPus. Foram realizadas microtomografias após cada procedimento para avaliar o volume de material remanescente, a extrusão após o uso dos instrumentos reciprocantes, o volume final da obturação ao final do retratamento e o volume na área de istmo, tanto após a obturação original quanto após a re-obturação. Os resultados obtidos mostraram que, no tratamento inicial, a patência do canal (ou glidepath) realizado com instrumentos Pathfile previamente ao uso dos instrumentos Reciproc R25 possibilitou que a obturação dos canais atingisse um limite significativamente (P < 0,05) mais próximo ao forame apical no grupo RHPui, onde o glidepath foi realizado em toda a extensão do canal. Em relação aos diferentes protocolos de retratamento, não houve remoção completa do material obturador do interior dos canais nos dois grupos estudados em todos os níveis avaliados, sem diferença estatisticamente significativa (P > 0,05) entre os grupos com relação a essa variável. Na avaliação intragrupo, houve uma diferença estatisticamente significativa (P < 0,05) entre os passos do procedimento em relação à redução do volume de material obturador, tanto na extensão total do canal, quanto nos seus diferentes níveis, com exceção do terço médio após o Hyflex, no terço cervical após o Mtwo e no terço médio após o EasyClean. O volume do material obturador final foi significativamente maior (P < 0,05) do que o volume do material obturador original, nos dois grupos estudados. O volume de material obturador na região do istmo foi significativamente maior (P < 0,05) após a re-obturação nos dois grupos, sendo significativamente maior (P < 0,05) no grupo RMEasy do que no grupo RHPui. Não houve diferença estatística (P > 0,05) entre os grupos com relação ao tempo total despendido na remoção do material obturador (P > 0,05), sendo 209,40 s para o Grupo RHPui e 227,40 s para o Grupo RMEasy. Não houve diferença estatística (P > 0,05) entre os grupos com relação ao volume da extrusão de material obturador, sendo 0,0258 mm3 (0 0,954) no Grupo RHPui e 0,0037 mm3 (0 0,565) no Grupo RMEasy. Os testes de Shapiro-Wilks, Mann- Whitney, Wilcoxon, Friedman e Dunn foram utilizados na análise dos dados.

Au sein des Réacteurs à Eau Pressurisée, le flux de neutrons entraîne une modification des propriétés mécaniques des gaines à combustible en alliage de zirconium. Bien que leur comportement macroscopique soit bien connu, les mécanismes microscopiques de la déformation des alliages de zirconium restent à caractériser. Afin de simuler l'irradiation aux neutrons, des irradiations aux particules chargées (ions et électrons) ont été réalisées à 400 et 450°C sur un alliage de zirconium: le Zircaloy-4 RXA. L'analyse expérimentale de la microstructure obtenue après irradiation, effectuée au Microscope Electronique en Transmission (MET), a montré la présence de défauts cristallins: les boucles de dislocation de vecteur de Burgers <a>. Leur évolution au cours de l'irradiation (taille et densité), ainsi que leurs caractéristiques (nature et plan d'habitat) ont été déterminées et discutées sur la base de la diffusion des défauts ponctuels. Les résultats obtenus suggèrent une diffusion des auto-interstitiels très faiblement anisotrope. Des expériences de traction in-situ ont été réalisées au MET, après irradiation aux ions, afin d'activer le glissement des dislocations et d'observer leurs interactions avec ces boucles <a>. Certains cas d'interactions observés expérimentalement ont été modélisés par Dynamique des Dislocations pour une meilleure compréhension des mécanismes. L'effet simultané de la contrainte et de l'irradiation sur les mécanismes de déformation a ensuite été étudié. Des irradiations in-situ aux électrons et aux ions ont été effectuées, sans et avec application d'une contrainte. Des mécanismes de déformation impliquant la montée des dislocations ont ainsi été mis en évidence. Grâce à l'ensemble de cette étude, des modèles basés sur les mécanismes identifiés pourront être, à terme, proposés afin de prédire le comportement des alliages de zirconium en réacteur. / In Pressurized Water Reactors, the neutron flux leads to a change in the mechanical properties of the fuel cladding tubes made of zirconium alloys. Although their macroscopic behavior is well known, the microscopic deformation mechanisms of zirconium alloys still need to be characterized. In order to simulate the neutron irradiation, charged particles irradiations (ion and electron) were carried out at 400°C and 450°C on a zirconium alloy: RXA Zircaloy-4. The experimental analysis of the irradiated microstructure, performed by using a Transmission Electron Microscope (TEM), have shown some crystalline defects: dislocation loops with a <a> Burgers vector. Their evolution (size and density) and their characteristics (nature and habit plane) have been determined and discussed based on the point defects diffusion. The results suggest a weak anisotropy in the self-interstitial diffusion. In-situ tensile tests were performed using a TEM, after ion irradiation, in order to activate the dislocation glide and to observe their interaction with the <a> loops. Some of the experimental cases of interaction have been simulate using Dislocation Dynamics for a better understanding of the mechanisms. The simultaneous effect of the stress and of the irradiation on the deformation mechanisms have been then studied. In-situ electron and ion irradiations were conducted, with and without an applied stress. Deformation mechanisms involving dislocation climb have thus been demonstrated. Through this study, models based on the identified mechanisms may be suggested, in order to predict the behavior of zirconium alloys in the reactor.

In this thesis, we analyze the electromagnetic wave propagation in waveguidestructuresexhibiting periodical geometry, including glide symmetry. The analysisis performed using a mode matching technique which correlates the different modecoefficients from separate but, connected regions in the structure. This technique isused to obtain the dispersion diagrams for two one-dimensional periodic structures:a glide-symmetric corrugated metasurface and a coaxial line loaded with periodicholes. The mode matching formulation is presented in Cartesian and cylindricalcoordinate system for the former and the later, respectively. The mode matchingresults are compared to simulated results obtained from the Eigenmode Solver inCST Microwave Studio and are found to agree very well. / I detta examensarbete, analyseras elektromagnetisk v°agutbredning i periodiskav°agledarstrukturer som uppvisar glid symmetri. Analysen genomf¨ordes genom enmod matchnings-teknik som korrelerar de olika mod-koefficienterna fr°an separeraderegioner i strukturen med varandra. Denna teknik anv¨ands f¨or att ta framdispersionsrelationen f¨or tv°a endimensionella periodiska strukturer: en glid symmetriskkorrugerad meta-yta och en koaxial ledare belagd med periodiskt urgr¨opdah°aligheter. Mod matchnings-formuleringen presenteras i Kartesiska och cylindriskakoordinatsystem respektive f¨or de ovan n¨amnda fallen. Mod matchnings-resultatenj¨amf¨ors med data-simulerade resultat erh°allna fr°an CST Microwave Studio och de¨overenst¨ammer v¨al med varandra.