The advent of extreme-scale computing systems, e.g., Petaflop supercomputers, High Performance Computing (HPC) cyber-infrastructure, Enterprise databases, and experimental facilities such as large-scale particle colliders, are pushing the envelope on dataset sizes.  Supercomputing centers routinely generate and consume ever increasing amounts of data while executing high-throughput computing jobs. These are often result-datasets or checkpoint snapshots from long-running simulations, but can also be input data from experimental facilities such as the Large Hadron Collider (LHC) or the Spallation Neutron Source (SNS). These growing datasets are often processed by a geographically dispersed user base across multiple different HPC installations.  Moreover, end-user workflows are also increasingly distributed in nature with massive input, output, and even intermediate data often being transported to and from several HPC resources or end-users for further processing or visualization. The growing data demands of applications coupled with the distributed nature of HPC workflows, have the potential to place significant strain on both the storage and network resources at HPC centers. Despite this potential impact, rather than stringently managing HPC center resources, a common practice is to leave application-associated data management to the end-user, as the user is intimately aware of the application's workflow and data needs. This means end-users must frequently interact with the local storage in HPC centers, the scratch space, which is used for job input, output, and intermediate data. Scratch is built using a parallel file system that supports very high aggregate I/O throughput, e.g., Lustre, PVFS, and GPFS. To ensure efficient I/O and faster job turnaround, use of scratch by applications is encouraged.  Consequently, job input and output data are required to be moved in and out of the scratch space by end-users before and after the job runs, respectively. In practice, end-users arbitrarily stage and offload data as and when they deem fit, without any consideration to the center's performance, often leaving data on the scratch long after it is needed. HPC centers resort to "purge" mechanisms that sweep the scratch space to remove files found to be no longer in use, based on not having been accessed in a preselected time threshold called the purge window that commonly ranges from a few days to a week. This ad-hoc data management ignores the interactions between different users' data storage and transmission demands, and their impact on center serviceability leading to suboptimal use of precious center resources. To address the issues of exponentially increasing data sizes and ad-hoc data management, we present a fresh perspective to scratch storage management by fundamentally rethinking the manner in which scratch space is employed. Our approach is twofold. First, we re-design the scratch system as a "cache" and build "retention", "population", and "eviction"  policies that are tightly integrated from the start, rather than being add-on tools. Second, we aim to provide and integrate the necessary end-user data delivery services, i.e. timely offloading (eviction) and just-in-time staging (population), so that the center's scratch space usage can be optimized through coordinated data movement. Together, these two combined approaches create our Integrated End-User Data Service, wherein data transfer and placement on the scratch space are scheduled with job execution. This strategy allows us to couple job scheduling with cache management, thereby bridging the gap between system software tools and scratch storage management. It enables the retention of only the relevant data for the duration it is needed. Redesigning the scratch as a cache captures the current HPC usage pattern more accurately, and better equips the scratch storage system to serve the growing datasets of workloads. This is a fundamental paradigm shift in the way scratch space has been managed in HPC centers, and outweighs providing simple purge tools to serve a caching workload. / Ph. D.

Much of software engineering research and practice is concerned with improving software quality. While enormous prior efforts have focused on improving the quality of programs, this dissertation instead provides the means to educate the next generation of programmers who care deeply about software quality. If they embrace the culture of quality, these programmers would be positioned to drastically improve the quality of the software ecosystem. This dissertation describes novel methodologies, techniques, and tools for introducing novice programmers to software quality and its systematic improvement. This research builds on the success of Scratch, a popular novice-oriented block-based programming language, to support the learning of code quality and its improvement. This dissertation improves the understanding of quality problems of novice programmers, creates analysis and quality improvement technologies, and develops instructional approaches for teaching quality improvement. The contributions of this dissertation are as follows. (1) We identify twelve code smells endemic to Scratch, show their prevalence in a large representative codebase, and demonstrate how they hinder project reuse and communal learning. (2) We introduce four new refactorings for Scratch, develop an infrastructure to support them in the Scratch programming environment, and evaluate their effectiveness for the target audience. (3) We study the impact of introducing code quality concepts alongside the fundamentals of programming with and without automated refactoring support. Our findings confirm that it is not only feasible but also advantageous to promote the culture of quality from the ground up. The contributions of this dissertation can benefit both novice programmers and introductory computing educators. / Doctor of Philosophy / Software remains one of the most defect-prone artifacts across all engineering disciplines. Much of software engineering research and practice is concerned with improving software quality. While enormous prior efforts have focused on improving the quality of programs, this dissertation instead provides the means to educate the next generation of programmers who care deeply about software quality. If they embrace the culture of quality, these programmers would be positioned to drastically improve the quality of the software ecosystem, akin to professionals in traditional engineering disciplines. This dissertation describes novel methodologies, techniques, and tools for introducing novice programmers to software quality and its systematic improvement. This research builds on the success of Scratch, a popular visual programming language for teaching introductory students, to support the learning of code quality and its improvement. This dissertation improves the understanding of quality problems of novice programmers, creates analysis and quality improvement technologies, and develops instructional approaches for teaching quality improvement. This dissertation contributes (1) a large-scale study of recurring quality problems in Scratch projects and how these problems hinder communal learning, (2) four new refactorings, quality improving behavior-preserving program transformations, as well as their implementation and evaluation, (3) a study of the impact of introducing code quality concepts alongside the fundamentals of programming with and without automated refactoring support. Our findings confirm that it is not only feasible but also advantageous to promote the culture of quality from the ground up. The contributions of this dissertation can benefit both novice programmers and introductory computing educators.

L’évolution de la microélectronique suit plusieurs axes notamment la miniaturisation des éléments actifs (réduction de taille des transistors), et l’augmentation de la densité d’interconnexion qui se traduisent par la loi de Gordon Moore qui prédit que la densité d'intégration sur silicium doublerait tous les deux ans. Ces évolutions ont pour conséquence la réduction des prix et du poids des composants. L’hybridation ou flip chip est une technologie qui s’inscrit dans cette évolution, elle consiste en l’assemblage de matériaux hétérogènes. Dans cette étude il s‘agit d’un circuit de lecture Silicium et d’un circuit de détection InP ou GaAs assemblés par l’intermédiaire d’une matrice de billes d’indium. La connexion flip chip est basée sur l’utilisation d’une jonction par plots métalliques de faibles dimensions qui permet de diminuer les pertes électriques (faible inductance et faible bruit), une meilleure dissipation thermique, une bonne tenue mécanique. Enfin elle favorise la miniaturisation avec l’augmentation de la compacité et de la densité d’interconnexion.Les travaux de thèse se concentrent sur deux axes principaux. Le premier concerne l’hybridation par brasure avec la technologie des billes d’indium par refusion, et le second concerne l’hybridation par pression à température ambiante (nano-scratch) par l’intermédiaire des nanostructures (Nano-fils d’or, Nano-fils ZnO). Ces travaux ont permis la réalisation d’un détecteur InGaAs avec extension visible de format TV 640*512 pixels au pas de 15 µm. Ces travaux ont également permis la validation mécanique de l’assemblage d’un composant de format double TV 1280*1024 pixels au pas de 10 µm par cette même méthode de reflow. Pour l’axe hybridation à froid, nos travaux ont permis la validation d’une méthode de croissance de nano-fils ZnO par une voix hydrothermique à basse température (<90°C). / Evolution of microelectronics follows several major roads, in particular the size decrease of active elements (reduction of size of transistors), better electrical performances, high I/O density and smaller size. This revolution has been predicted by Gordon Moore who suggested that integrated circuits would double in complexity every 24 months. As a consequence, this evolution induces both the reduction of prices and the weight of components.The term flip chip describes the method of electrically connecting the die to the package substrate. Flip chip microelectronic assembly is the direct electrical connection of face-down (or flipped) integrated circuit (IC) chips onto substrates, circuit boards, or carriers, using conductive bumps on the chip bond pads. Flip chip offers the highest speed electrical performance, reduces the delaying inductance and capacitance of the connection, Smallest Size Greatest I/O Flexibility, Most Rugged, high I/O density and Lowest Cost.This thesis work study concentrates on two main directions. The first one concerns hybridization by means of the technology of Indium bumps associated to a reflow process and the second one is about pressure induced hybridization at low temperature using nanostructures (Nano-scratch). In this work, we have developed a complete process to assemble a focal plane array format of 640 x 512 pixels with a pitch of 15 µm. These studies also allowed the mechanical validation of hybridization of a focal plane arrays 1280*1024 pixels with a pitch of 10 µm. Concerning alternative technologies to flip chip reflow, we introduced and demonstrate the relevance of a method of growth of ZnO nanorods using low temperature wet chemical growth and further hybridization at ambient temperature.

Acompanha: O software de programação Scratch na formação inicial do professor de matemática por meio da criação de objetos de aprendizagem / Este trabalho foi motivado pela crença de que a formação inicial de professores é um fator relevante na mudança de práticas pedagógicas e na transformação da cultura educacional. Com isso, dada as potencialidades do software de programação Scratch para fins educacionais, este estudo propôs, em uma turma de Licenciatura em Matemática, na disciplina de Mídias Tecnológicas no Ensino de Matemática de uma universidade pública do Estado do Paraná, o desenvolvimento de objetos de aprendizagem no formato de jogos digitais para o ensino de Geometria. Para analisar as contribuições dos objetos criados no estudo de conceitos geométricos, foram definidos critérios presentes na definição do Grupo de Pesquisa em Tecnologias na Educação Matemática (GPTEM) de objetos de aprendizagem. Inicialmente, buscando unir formação inicial de professores, ensino de Matemática e tecnologia, a pesquisa se fundamentou em autores da área da educação que defendem o uso de tecnologias educacionais, formação de professores e documentos oficiais de ensino. A dissertação discorreu sobre o ensino de Matemática no Brasil e a formação inicial de professores, pautada nos saberes docentes, à luz das tecnologias educacionais digitais. Igualmente foram apresentadas as características e potencialidades do Scratch como recurso educacional. Em seguida, foram analisados os objetos criados pelas duplas que atuaram como sujeitos da pesquisa, apresentando suas contribuições e limitações ao ensino de tópicos de geometria propostos, assim como as contribuições que a experiência de desenvolver um artefato próprio trouxe à sua formação inicial. Feitas as análises, verificou-se que apenas um objeto de aprendizagem trata o erro com uma abordagem diferenciada, que é um critério essencial para que o objeto seja construcionista. Contudo, também foi apontado que a maioria deles possuem pelo menos três dos critérios selecionados, de modo que os mesmos contribuem com o ensino de Geometria. Por fim, constatou-se que o software de programação Scratch, na formação inicial de professores de Matemática, contribui com o ensino de Geometria por meio do desenvolvimento de Objetos de Aprendizagem promovendo reflexões e aprendizagens relevantes à formação. / This work was motivated by the belief that the initial formation of teachers is a relevant factor in the change of pedagogical practices and in the transformation of the educational culture. With this, given the potential of the Scratch programming software for educational purposes, this study proposed, in a class of Mathematics Degree, in the discipline of Technological Media in Mathematics Teaching of a public university of the State of Paraná, the development of objects of learning in the form of digital games for the teaching of Geometry. In order to analyze the contributions of objects created in the study of geometric concepts, criteria were defined in the definition of the Group of Research in Technologies in Mathematics Education (GPTEM) of learning objects. Initially, seeking to unite initial teacher training, mathematics teaching and technology, the research was based on authors in the area of education who advocate the use of educational technologies, teacher training and official teaching documents. The dissertation discussed the teaching of Mathematics in Brazil and the initial teacher training, based on the teaching knowledge, in the light of digital educational technologies. The characteristics and potentialities of Scratch as an educational resource were also presented. Next, the objects created by the pairs that acted as subjects of the research were analyzed, presenting their contributions and limitations to the teaching of proposed geometry topics, as well as the contributions that the experience of developing an own artifact brought to their initial formation. After the analysis, it was verified that only one learning object treats the error with a differentiated approach, which is an essential criterion for the object to be constructional. However, it was also pointed out that most of them have at least three of the criteria selected, so that they contribute to the teaching of Geometry. Finally, it was found that Scratch programming software, in the initial formation of Mathematics teachers, contributes with the teaching of Geometry through the development of Learning Objects promoting reflections and learning relevant to the formation.

The microelectronics industry requires continuous advances due to ever-evolving technology and the corresponding need for higher density substrates with smaller features. Specifically, new dielectric materials with enhanced electrical properties are needed. At the same time, adhesion must be maintained in order to preserve package reliability and mechanical performance. As a result, this research investigates the use of thin glass sheets as an alternative substrate material as it offers a number of advantages including coefficient of thermal expansion similar to silicon, good dielectric properties and optical transparency to assist in the alignment of buried features. As part of this project it was necessary to deposit metallic coatings onto the glass sheets to create electrical tracks, pads and microvias. In order to meet these requirements, the metallisation of both smooth as received glass surfaces and surfaces roughened by laser machining using electroless copper and nickel deposition were investigated. This study resulted in a number of important conclusions about the roles of chemical bonding and mechanical anchoring in both the adhesion and catalyst adsorption, that are key factors in the electroless metallisation process.....

A inclusão de crianças com deficiência em escolas regulares, ocorrida seguindo a Lei 13.146 de 06 de julho de 2015, que institui a Lei Brasileira de Inclusão da Pessoa com Deficiência, exige que as atividades escolares sejam acessíveis a todas as crianças. Entre as atividades escolares, as atividades de programação têm se espalhado nas escolas devido aos benefícios gerados nas habilidades dos alunos, como criatividade e pensamento lógico. Atualmente, essas atividades utilizam principalmente ambientes de programação em blocos, como o Scratch, que focam em aspectos visuais para interação, contando com cores, formatos e utilização do mouse. Nesse contexto, e de grande importância o estudo de interfaces de programação para que crianças com deficiência visual possam ser incluídas e participem em conjunto com as outras crianças. Este projeto busca investigar este tema, bem como propor e avaliar um sistema para atividades de introdução à programação para crianças cegas e videntes. Foi proposto um sistema formado por peças tangíveis, em que os blocos digitais foram substituídos por peças físicas com formas para reconhecimento tátil e respostas auditivas. Foi adotado um modelo cíclico para o desenvolvimento do protótipo que garantiu duas etapas de testes com usuários. Na primeira etapa foram 4 participantes videntes, sendo que três participaram vendados, e a partir das observações foram gerados novos requisitos e modificações no protótipo. Na segunda etapa participaram 2 crianças cegas e os resultados destes testes geraram requisitos específicos para a utilização do sistema por crianças cegas. Este trabalho traz como contribuição final um conjunto de recomendações para o desenvolvimento de sistemas que permitam a crianças cegas e videntes brincarem juntas em atividades de programação. / The inclusion of children with disabilities in regular schools, following Law 13,146 of July 6, 2015, which establishes the Brazilian Law on the Inclusion of Persons with Disabilities, requires that school activities be accessible to all children. Among school activities, programming activities have spread in schools because of the benefits generated in students\' skills such as creativity and logical thinking. Currently, these activities mainly use blocks programming environments, such as Scratch, that focus on visual aspects for interaction, counting on colors, shapes and mouse usage. In this context, it is of great importance to study programming interfaces so that children with visual impairment can be included and participate together with other children. This project seeks to investigate this theme as well as to propose and evaluate a system for introductory programming activities for blind and sighted children. It was proposed a system formed by tangible pieces in which the digital blocks were replaced by physical pieces with forms for tactile recognition and auditory responses. It was adopted a cyclical model for the development of the prototype that guaranteed two stages of testing with users. In the first stage, four sighted participants, three were blindfolded among them, and and from the first observations were generated new requirements and modifications in the prototype. The second stage involved 2 blind children and the results of these tests generated specific requirements for the use of the system by blind children. This work brings as final contribution a set of recommendations for the development of systems that allow blind and sighted children to play together in programming activities.

The purpose of this bachelor thesis was to present a solution for how a graphical programming language with a functional mindset can be constructed with the help of inspiration from functional programming. An artefact was created by using design science as a research methodology and has in several iterations gone through development and testing to reassure the outcome works as intended. The graphical programming language which has been developed is a language that allows the programmer to code in depth, functions are written as blocks inside blocks and the language is made compact. A code structure in a JSON-format was developed at the same time as G#, allowing it to be presented in a texted data format. The purpose of the JSON-format was to enable execution of G# and the transformation to a text-based programming language. Implications can be made from this study by learning about how a graphical programming language can be built from scratch and what difficulties needs to be tackled to get a result that works as intended. G# was developed to only support a few selected and commonly used functions in programming due to time limitations. The final version of G# in this study can do calculations, handle lists and perform less complex algorithms. Under the development of G#’s graphical functions, the free tool Draw.io was used. Unknowingly from the start, Draw’s limitations made it not perform as expected. Therefore, it is recommended to investigate which available tools are most suited for the construction of the graphical functions before development begins. / Syftet med examensarbetet var att med hjälp av inspiration från funktionell programmering, presentera en lösning på hur ett nytt grafiskt programmeringsspråk med ett funktionellt djup och tänk kan konstrueras. Med hjälp av designbaserad forskning har en artefakt tagits fram som genomgått iterationer av utveckling och testning för att uppnå ett resultat som fungerar som tänkt. Det grafiska språket som tagits fram kallas för G# och är ett språk som tillåter programmeraren att programmera på djupet, funktioner skrivs som block inuti block och språket blir kompakt. Tillhörande G# så konstruerades en struktur i ett JSON-format för hur funktioner i G# kan representeras i ett textat dataformat. Syftet med JSON-formatet var att möjliggöra exekvering av G# och transformering till ett textbaserat programmeringsspråk. Av denna studie kan det dras lärdomar kring hur ett programmeringsspråk kan byggas upp från grunden och vilka svårigheter som måste tacklas för att få ett resultat som fungerar. På grund av begränsning av tid så utvecklades endast vanligt förekommande funktioner inom programmering till G#, språkets slutversion kan göra beräkningar, sköta hantering av listor och utföra enklare algoritmer. Vid utvecklingen av G# användes verktyget Draw.io för att konstruera funktioner. Verktyget var begränsat i funktionalitet och presterade inte enligt förväntan. Därför borde en undersökning som svarar på vilket typ av verktyg som är mest lämpligt för utvecklingen av de grafiska funktionerna göras innan utvecklingen börjar.

O presente estudo propõe-se responder à questão de investigação: Quais são as evidências de pensamentos matemáticos e como os alunos as expressam em atividades de programação envolvendo o conceito de ângulo? A pesquisa compreende um estudo de caso realizado com 16 alunos do 6º ano do ensino fundamental de uma escola da rede pública municipal de São Leopoldo. Os alunos participaram de 11 encontros semanais, dentro da sua carga horária de aula, em que solucionaram situações variadas propostas pela pesquisadora e produziram um jogo. Todas as atividades foram desenvolvidas no Scratch, visando à compreensão do conceito de ângulo e de conceitos básicos de programação. Durante a realização das atividades, os alunos eram observados e entrevistados. As entrevistas foram inspiradas no método clínico, criado por Piaget, que busca auxiliar na compreensão do curso do pensamento dos sujeitos Além disso, foram utilizados como material de análise vídeos das interações com os alunos, arquivos produzidos no Scratch e registros dos alunos em uma página na internet. A análise de dados está apoiada na Teoria dos Campos Conceituais proposta por Gérard Vergnaud e na busca por aproximações e distanciamentos na psicogênese das condutas cognitivas da criança em interação com o mundo do computador, observadas por Léa Fagundes. Os resultados apontam para evoluções na compreensão do conceito de ângulo, permitindo identificar fases e subfases nas quais os alunos apresentam seus esquemas em relação ao conceito de ângulo e apropriação da linguagem de programação do software. / The present study proposes to answer the research question: What are the evidences of mathematical thinking and how do the students express them in programming activities involving the angle concept? The research comprises a case study carried out with 16 students from 6th grade of elementary school in a public school in São Leopoldo. The students took part of 11 weekly meetings, within their class schedule, in which they solved varied situations proposed by the researcher and produced a game. All activities were developed in Scratch, aiming at understanding the concept of angle and basic programming concepts. During the activities, the students were observed and interviewed The interviews were inspired in clinical method, created by Piaget, which seeks to assist them in understanding the course of the subjects' reasoning. In addition, videos of interactions with students, files produced in Scratch and student records on a web page were used as analysis material. Data analysis is supported by the Theory of Conceptual Fields proposed by Gérard Vergnaud and the search for similarities and differences in the psychogenesis of the cognitive behavior of the child in interaction with the computing world, observed by Léa Fagundes. The results point to evolutions in the understanding of the concept of angle, allowing us to identify phases and subphases in which the students present their schemas in concerning the concept of angle and appropriation of the software programming language.

In this thesis, the behavior of pearlitic steel was characterized under controlled wear conditions in the laboratory and service conditions in two ore mining stages, comminution and transportation. The thesis consists in three experimental chapters, divided according to the tribosystems analyzed. On all the chapters Electro Microscopy techniques for the microstructural analysis were employed. Scanning Electron Microscopy (SEM), Focused Ion Beam (FIB-SEM), Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM) were used. The first experimental chapter shows the analysis of the pearlite under abrasive wear with loose abrasive particles in multi-events conditions. The sample was taken from Semi-Autogenous Grinding mills (SAG) and experimental simulation was carried out in laboratory using the Dry Sand Rubber Wheel Abrasion Test (DSRW). The results show a polycrystalline layer formation in both cases, characterized by ultra-fine grains of ferrite in the layer closer to the surface. It was also concluded that the DSRW can simulate the wear produced on field (superficial and microstructural features) in conditions of higher normal load than recommended by the ASTM Standard G65. The second experimental chapter explores the characterization of the microstructure after the indenter pass in scratch test using two conditions of normal load applied and five sequences of scratch. The microstructural analysis shows the formation of two subsuperficial layers identified by the level of the microstructural alterations. In the subsuperficial layer (close to the surface), the formation of new ultra-fine grains of ferrite was observed. A second layer was observed deeper in the sample and denominated as layer of the microstructure transition, characterized by the combination of deformed (reduction of the interlamellar spacing) and pearlite colonies not affected plastically by the mechanical loading. On this layer, the crystallographic texture in RD // in samples tested at 4 N (normal load) and one-pass scratch was determined. Later, on this chapter, the microstructure in a ground rail (industrial procedure characterized as a multi-event scratch test) was analyzed. Two grinding conditions were used for the analysis with variation of the grinding linear speed and load on the grinding stones (discs). The combination of low grinding speed and high load promotes a higher deformed layer formation beneath the patch zone and low randomized orientation of the pearlite colonies. Finally, in the third experimental chapter, the pearlitic characterization was concluded with the study of samples of railway wheel and rail under wear in service and Rolling Contact Fatigue (RCF) in laboratory. The laboratorial simulation was carried out using the twin-disc rolling contact tribometer with a variation of number of cycles. The characterization of railway wheel shows that the WEL is characterized by levels of breaking and aligned cementite and zones with dissolution of the carbon atom in the ferrite to form the supersaturated carbon ferrite. The polycrystalline ferrite formation (ultra-fine grains) in the sub-superficial layer and it was identified a preferential orientation of RD // in the layer of microstructural transition. The results of the laboratory test show surface crack nucleation and propagation at low angle in the more severe deformed layer. The microstructure of the layer consists in polycrystalline ferrite and the cementite dissolution. / Nesta tese foi caracterizado o comportamento do aço perlítico em condições controladas de desgaste em laboratório e em serviço em dois estágios do processo de mineração de minério, cominução e transporte ferroviário. A tese consiste em três capítulos experimentais divididos segundo o tribosistema analisado. Em todos os capítulos do trabalho foi utilizada a técnica de microscopia eletrônica para análise microestrutural. Foi utilizado Microscopia eletrônica de varredura (MEV), Focused Ion Beam (FIB-SEM), Electron Backscatter Diffraction (EBSD) e Microscopia eletrônica de transmissão (MET). O primeiro capítulo experimental mostra a análise da perlita in condições de desgaste abrasivo com partículas soltas em eventos múltiplos. As amostras foram tiradas de um moinho semi-autógeno (SAG) e realizada uma simulação experimental do desgaste em condições controladas usando o tribômetro de roda de borracha (RWAT). Os resultados mostraram a formação de camada branca em ambas as condições de análise, consistindo em uma camada poli cristalina caracterizada pela formação de grãos ultrafinos na camada mais próxima da superfície de desgaste. Também foi concluído que a roda de borracha pode simular o desgaste produzido nos moinhos SAG tanto nas características superficiais quanto microestruturais em condições de maior severidade as comumente utilizadas na norma ASTM G65 (procedimento B). O Segundo capítulo experimental explora a caracterização da microestrutura depois da passagem do endentador no ensaio de riscamento (scratch test) utilizando duas condições de carga normal aplicada e 5 sequências de riscamento. A análise microestrutural mostrou a formação de duas camadas subsuperficiais identificadas pelo nível de alteração microestrutural. Na camada mais próxima da superfície de desgaste foi observada a formação de grãos ultrafinos de ferrita. A segunda camada identificada mais profundamente na amostra, denominada como camada de transição, é caracterizada pela combinação de colônias deformadas (redução do espaçamento interlamelar) e camadas não afetadas pelos esforços produzidos no contato. Nesta camada foi determinada a texturização em direção RD // nas amostras testadas a 4 N (carga normal aplicada) e uma passada. Posteriormente à análise de riscamento foi caracterizada a microestrutura de uma amostra tirada de um trilho esmerilhado (processo industrial que pode ser considerado como aplicação do ensaio de riscamento). Foram consideradas duas condições de esmerilhamento com variação de velocidade de esmerilhamento (deslocamento linear do veículo esmerilhador) e potência dos motores dos rebolos usada no procedimento. A combinação de baixa velocidade de esmerilhamento e alta potência nos motores controladores dos rebolos promoveu uma grande deformação nas camadas subsuperficiais na região de contato e uma baixa aleatoriedade das orientações cristalográficas das colônias de perlita. Finalmente, no capítulo três, a caracterização da microestrutura perlitica foi finalizada com o estudo de amostras de roda e trilho em condições de desgaste em campo e de Rolling Contact Fatigue (RCF) em ensaios de laboratório. A simulação experimental foi realizada utilizando o tribômetro twin-disc rolling (configuração disco-disco) com variação do número de ciclos. A caracterização da roda ferroviária mostrou a formação da camada branca caracterizada por níveis de cementita fraturada e alinhada em direção do movimento de rolamento/deslizamento com áreas de dissolução do átomo de carbono na ferrita formando uma ferrita supersaturada. Foi identificado a formação de policristais de ferrita (grãos ultrafinos) na camada mais superficial e uma orientação preferencial RD // na camada de transição. Os resultados dos ensaios de laboratório mostraram a nucleação de trincas superficiais se propagando a baixo ângulo na camada branca. A transformação microestrutural dessa camada após ensaios de laboratório consiste em policristais de ferrita e dissolução da cementita.

A inclusão de crianças com deficiência em escolas regulares, ocorrida seguindo a Lei 13.146 de 06 de julho de 2015, que institui a Lei Brasileira de Inclusão da Pessoa com Deficiência, exige que as atividades escolares sejam acessíveis a todas as crianças. Entre as atividades escolares, as atividades de programação têm se espalhado nas escolas devido aos benefícios gerados nas habilidades dos alunos, como criatividade e pensamento lógico. Atualmente, essas atividades utilizam principalmente ambientes de programação em blocos, como o Scratch, que focam em aspectos visuais para interação, contando com cores, formatos e utilização do mouse. Nesse contexto, e de grande importância o estudo de interfaces de programação para que crianças com deficiência visual possam ser incluídas e participem em conjunto com as outras crianças. Este projeto busca investigar este tema, bem como propor e avaliar um sistema para atividades de introdução à programação para crianças cegas e videntes. Foi proposto um sistema formado por peças tangíveis, em que os blocos digitais foram substituídos por peças físicas com formas para reconhecimento tátil e respostas auditivas. Foi adotado um modelo cíclico para o desenvolvimento do protótipo que garantiu duas etapas de testes com usuários. Na primeira etapa foram 4 participantes videntes, sendo que três participaram vendados, e a partir das observações foram gerados novos requisitos e modificações no protótipo. Na segunda etapa participaram 2 crianças cegas e os resultados destes testes geraram requisitos específicos para a utilização do sistema por crianças cegas. Este trabalho traz como contribuição final um conjunto de recomendações para o desenvolvimento de sistemas que permitam a crianças cegas e videntes brincarem juntas em atividades de programação. / The inclusion of children with disabilities in regular schools, following Law 13,146 of July 6, 2015, which establishes the Brazilian Law on the Inclusion of Persons with Disabilities, requires that school activities be accessible to all children. Among school activities, programming activities have spread in schools because of the benefits generated in students\' skills such as creativity and logical thinking. Currently, these activities mainly use blocks programming environments, such as Scratch, that focus on visual aspects for interaction, counting on colors, shapes and mouse usage. In this context, it is of great importance to study programming interfaces so that children with visual impairment can be included and participate together with other children. This project seeks to investigate this theme as well as to propose and evaluate a system for introductory programming activities for blind and sighted children. It was proposed a system formed by tangible pieces in which the digital blocks were replaced by physical pieces with forms for tactile recognition and auditory responses. It was adopted a cyclical model for the development of the prototype that guaranteed two stages of testing with users. In the first stage, four sighted participants, three were blindfolded among them, and and from the first observations were generated new requirements and modifications in the prototype. The second stage involved 2 blind children and the results of these tests generated specific requirements for the use of the system by blind children. This work brings as final contribution a set of recommendations for the development of systems that allow blind and sighted children to play together in programming activities.