O concreto auto-adensável (CAA), que representa um dos mais significativos avanços na tecnologia de concreto, foi desenvolvido no Japão em 1988 com o intuito de se obter estruturas de concreto duráveis. É um concreto que dispensa o processo convencional de vibração ou adensamento por ter a capacidade de fluir e preencher os espaços da fôrma apenas através de seu peso próprio. Desde então, várias pesquisas têm sido realizadas e esse tipo de concreto já vem sendo aplicado na prática há algum tempo em alguns países, principalmente por grandes empresas de construção no Japão e na Suécia. Pesquisas para se estabelecerem métodos racionais de dosagem para CAA bem como métodos de ensaios no estado fresco têm sido desenvolvidas, visando fazer do CAA um concreto de aplicação comum. Contudo, ainda não se conhece bem este material e o que se nota é que a maioria dos CAA apresentados em trabalhos científicos é obtida com altos teores de argamassa, além da grande dispersão desses teores. Neste trabalho foi estudada a influência do teor de argamassa sobre as características de concretos auto-adensáveis, tanto no estado fresco como no estado endurecido, produzidos a partir de diferentes teores de argamassa (55, 60, 65, 70 e 75%). Para a produção dos mesmos foi aplicado um novo método de dosagem para CAA desenvolvido por Tutikian (2004), o qual se mostrou satisfatório no que diz respeito às propriedades de fluxo dos CAA. Em termos de resistências mecânicas os CAA´s obtidos apresentaram comportamentos bem similares uns aos outros para relações a/c aproximadas e mesmo teor de fíler calcário (que substitui parte do teor de agregado miúdo total) . Porém, o consumo de aditivo superplastificante tende a aumentar, para uma mesma fluidez, com o aumento do teor de argamassa, o que se caracteriza pelo aumento da superfície específica da mistura para altos teores de argamassa. Quando comparado com um concreto convencional com mesmo teor de argamassa o CAA apresentou qualidades similares ou ligeiramente superiores, com exceção de seu custo que é superior ao de um concreto convencional. Deste modo, o presente trabalho pretende contribuir para um melhor conhecimento e entendimento do CAA para que o mesmo possa ser aplicado com segurança em edificações e obras corrente de engenharia civil. / Self-compacting concrete (SCC), first developed in Japan in 1988 to achieve durable concrete structures, and adopted in Europe and the rest of the world more recently, represents one of the most significant advances in concrete technology. SCC is a type of concrete that can flow and compact in a mould or formwork under its own weight without the need for vibration. Since then, several research activities have been carried out and this type of concrete has been used in practical structures in Japan and Sweden, mainly by large construction companies. Investigations for establishing rational mix design methods for SCC and self-compactability testing methods have been developed from the point of view of making this new concrete a standard concrete. However, SCC is not well known so far and it can be observed worldwide that most of the SCC has been proportioned with high mortar/paste contents. This work aims to assess the influence of the mortar content in the composition of SCC on its properties, both in fresh and hardened states, produced with five different mortar contents (55, 60, 65, 70, and 75%). The newly-developed mix design method (TUTIKIAN, 2004) was applied to produce all SCC, and it seemed to be a very good method in terms of the SCC flow properties. Concerning the mechanical properties (compressive/tensile strength) all SCC produced in this study have presented similar results related to others with approximate water-to-cement ratio and the same limestone filler content (used to replace part of the total fine aggregate content). It was verified that the superplasticizer dosage increases as the mortar content increases for the same values of flow properties, which can be explained by the greater specific surface of the mixtures as the mortar content increases. Compared to a normal vibrated concrete with the same mortar content in its composition, SCC presented equal or slightly better qualities, excepting the issue of costs which is more expensive than those of the normal vibrated concrete. This dissertation aims to contribute for a better knowledge and understanding of SCC so it can be safely applied in buildings and in civil engineering projects.

Os efeitos produzidos pela interação da radiação ionizante com os circuitos integrados podem ser classificados em efeitos de eventos únicos (Single Event Effects - SEE), comumente relacionados a problemas transientes, e efeitos de dose total ionizante (Total Ionization Dose - TID), os quais se originam em decorrência do longo tempo de exposição à radiação ionizante. Com relação à proteção desses circuitos, técnicas, como redundâncias temporais e espaciais, podem ser aplicadas a fim de reduzir a ocorrência de eventos transientes. Por outro lado, efeitos de TID e mesmo alguns SEE específicos, como os que causam degradações permanentes do circuito, podem ser atenuados drasticamente através de técnicas propostas em nível de layout. Nesse contexto, este trabalho analisa os conceitos básicos envolvidos na interação da radiação com o transistor MOS, desvios de suas características elétricas e técnicas de atenuação dos efeitos acumulativos aplicadas em níveis de arquitetura de sistemas, de processo de fabricação e de dispositivo. Contudo, este trabalho realiza uma abordagem mais detalhada de técnicas de tolerância em nível de layout. A tolerância em nível de layout do transistor é o resultado da combinação entre tecnologia escolhida agregada ao uso de anéis de guarda (guard rings) e aplicação de técnicas em nível de dispositivo como, por exemplo, a de geometria fechada (enclosed-gate). Este trabalho explora diferentes topologias de geometria fechada analisando diferentes modelagens e estimativas de razão de aspecto (W⁄L). Além disso, todas as análises e propostas apresentadas ao longo deste trabalho levam em conta o ambiente de projeto comercial, de forma que os dispositivos e técnicas propostas possam ser aplicadas e fabricadas utilizando ferramentas de projeto comerciais, respeitando restrições quando a dimensões e espaçamentos entre estruturas de acordo com requisitos comerciais de litografia. Os resultados obtidos corroboram o fato de que ao custo de área é possível que se obtenha um dispositivo mais tolerante à radiação e, neste caso, técnicas de mais alto nível ainda podem ser aplicadas de forma a atingir uma maior eficiência de proteção. / Studies related to ionizing radiation effects into MOS transistors are usually classified into two main groups, Single Event Effects (SEE) and Total Ionization Dose (TID). The former is related to transient effects and the later to the permanent effects which occurs during the whole lifetime of integrated circuits and devices. Architecture level for SEE mitigation techniques usually involves redundancy and majority voters, on the other hand, TID mitigation techniques act avoiding or reducing the weak and critical regions in the layout perspective. In this context this work proposes the analysis of primary physical mechanisms of radiation effects in semiconductor components and MOS transistors by exploring the electrical properties and related degradations. The mitigation (or hardening) techniques are explored not only at the architectural level but also by processes improvements. Nonetheless, this work is primarily focused to achieve a radiation hardened circuit by applying specific changes in the layout perspective making the design named as Radiation Hardened by Design (RHBD). Trading the area and circuit density it is possible to harden the most basic building block of electrical circuits (MOS transistors) and, in this case, by applying higher levels of mitigation techniques it is even possible to harden the entire circuit. Hardening by device is a combination of technology node, use of guard rings and techniques such as Enclosed Layout Transistor (ELT). Thus, this work realizes a comparative study of different proposed models to estimate the effective W/L aspect ratio in ELTs. Moreover, the analysis and approaches presented throughout this work take into account the commercial context, i.e., respecting the commercial Process Design Kits rules.

The theme of this diploma thesis is application of modern methods of cutting on selected parts in a concrete company. The base for technical - economical classification were both the real and the normative times. The conclusion of the thesis includes evaluation and the consequent results.

Diploma thesis deals with machining of hardened steels. In the introductory section it is described the physical process of cutting and basic used technologies of machining. The next chapter provides an overview of cutting materials. Other chapters deal with the workpiece material and heat treatment. Furthermore, there is made a comparison of the cutting conditions while machining of hardened steels by tools from selected manufacturers. As the conclusion there is the economic evaluation.

The thesis deals with machining of rotating parts made from hardened steel. The introductory chapter describes the problems of turning and grinding. The next chapter deals with heat treatment and machined materials. The next lists the used cutting materials. Criteria for evaluating the quality of the surface. A selection of cutting materials for the machining of hardened steels from selected manufacturers. The final chapter is a comparison of the described technologies.

Growing regions and tighter zoning in urban areas are pushing the hydrological bal-ances to establish new equilibriums which are causing a stress on the groundwater. Urbanization can affect the groundwater in several ways in which both raising and lowering of groundwater tables are a possibility. Both ways, sudden changes may bring on socioeconomic costs for the unprepared. Hydrogeological modelling creates the possibilities to visualise processes that cannot be seen with the naked eye. By combin-ing knowledge about the studied area from tests and measurements a conceptual model and additionally a numerical model can be created. To study the magnitude groundwater sensitivity to changes in land-cover a hydrogeological model was created using COMSOL multiphysics within the frame of a case study concerning a horse racetrack located in Täby, north of Stockholm. The model was calibrated against known data and was the applied on a future scenario where both the land-use and climate were changed. The outcome of the model showed that hydrogeological mod-elling is sensitive to the amount and quality of the in-data. Several insecurities in the results can be traced back to a lack of base material and by changing one parameter the result of other calibrated parameters would also change. Equifinality could thus be established to be a major issue when performing groundwater modelling. Further studies of relevant data requirements for different model objectives are required.

Five day old dark-grown seedlings of Secale cereale variety "coup;ar" p:rown at 20 C were subjected to hardening at 2 C "!.n daily increments from 0 to 7 days, to temperature stress at -5 C for 0, 1, and 3 days, and to recovery at 20 C for 0, I, and J days. Unhardened plants were killed by temperature stress but as the time of hardening increased fewer plants were killed. After 5 days of hardening all plants survived subsequent freezing stress. Mitochondria were isolated from the plants after they received various combinations of the three temperature treatments. There were 8 hardening levels, 3 stress levels, and 3 recovery levels giving a total of 8x3x30 72 treatments. Mitochondria from unstressed plants exhibited steady ADPIO ratios, RC ratios, and rate of state 3 respiration over the whole range of hardening and recovery times. Mitochondria from stressed plants were totally inactive with 0 or one day of hardening but as the time of hardening increased so did ADP: O ratio, R~ ratio, and ratp of state J respiratIon. After 5 days of hardenjng mitochondrla from hardened then stressed plants reached a maxImum level of activity. Evidently there was some change 1n the mttochondria during the hardening phase.

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第18413号 / 情博第528号 / 新制||情||93(附属図書館) / 31271 / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 小野寺 秀俊, 教授 守倉 正博, 教授 佐藤 高史 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

Student Number : 9800022T - PhD thesis - School of Mechanical, Industrial and Aeronautical Engineering - Faculty of Engineering and the Built Environment / For many applications, it may be useful to be able to estimate creep properties of a material from simpler testing procedures such as tensile tests than the conventional creep testing procedures. Most alloys used for creep service conditions are in a hardened condition and thus tertiary creep, controlled by micro structural degradation, is dominant. The object of the study was to investigate a reasonably simple method for estimating the creep behavior of a low alloy 1% Cr, 0.25 % Mo steel from tensile yield data. The study involved performing of series of investigations, including age hardening, tensile and creep tests. Microstructural degradation was monitored from specimens held in a furnace for different times and temperatures, which were then tested in tension at room temperatures. Tensile tests were carried out at different temperatures and strain rates and the data used to determine material parameters for use in kinetic equations describing deformation. For comparison, creep curves were obtained from both creep tests and tensile tests results. Tests on furnace aged specimens were used to quantify softening due to material degradation and formulate a structure evolution and kinetic expressions used to determine creep curves. The modified equation by Dorn was used to determine the material parameters and to predict flow characteristics. Two sets of mechanisms were observed. At low temperature and high stress (above 550MPa) dislocation by glide mechanism was investigated. At higher temperatures and low stress (below 550MPa), some form of power law creep was observed. Glide mechanism was investigated and material parameters σ ) , n and activation volume v, were calculated. The calculated value of σ ) was assumed for both plastic deformation and the softening kinetics. A reasonably good estimate of the creep behavior of the low alloy steel used in this investigation in which tertiary creep dominates can be calculated from tensile yield stress values. Furthermore, the creep rate and recovery have similar stress dependences, with the stress and temperature dependence similar to that predicted by recovery theory. The value of activation energy observed for creep for this alloy is in line with the processes which could be related to self diffusion. In order to justify the significance of this study, four existing empirical models are discussed, highlighting their merits and demerits with respect to the models used in this study. These are θ-Projection, Damage Mechanics, Estrin-Mecking and the Internal Stress Methods. Generally, in this class of alloys, recovery process occurs under an effective stress (i.e. an applied stress less the internal stress). Thus the possibility of using tensile data obtained in this study in the internals stress model was explored. The model could replicate the one used in this study if the change in internal stress value o σ is assumed to be negligible. This could be assumed to be true for tensile data at high stresses and low temperature especially during secondary creep rate when the internal stress approximates to the applied stress and at short test durations.

In recent years, the automotive industry has turned to press hardened steels (PHS) to improve passenger safety while enabling vehicle weight reduction. To form the complex shapes required for this purpose, they are often direct hot press formed. It is possible to provide corrosion resistance to these parts by galvanizing the PHS sheets prior to direct hot press forming (DHPF). However, the austenitization of the galvanized steel causes the Zn-based coating to transform into two intermetallic phases. These are iron-rich α-Fe(Zn) and zinc-rich Г-Fe3Zn10. The Г-Fe3Zn10 is liquid during traditional DHPF, and the applied stress can result in liquid metal embrittlement (LME). Recently, two new grades of PHS have been developed, which allow for DHPF at 600-700°C, below the Fe-Zn peritectic temperature at 782°C, thus avoiding LME. These prototype PHS grades are designated 2%Mn (0.2C-2Mn-0.25Si-0.005B (wt%)) and 2.5%Mn (0.2C-2.5Mn-0.25Si-0.005B (wt%)). The objective of this work is to determine the effect of DHPF on the ability of a Zn-based coating to provide robust cathodic protection to the two prototype PHS. Galvanized panels of both the 2%Mn and 2.5%Mn steel were DHPF with a U-shape die at 700°C. The surface and cross-section of the coating were examined to determine the effects of DHPF on the coating surface. Die friction during DHPF resulted in die wiping on the wall of the part, leading to removal of surface Г-Fe3Zn10. In cross-section, coating cracks were present at the wall and corner of the U-shape part due to the deformation during DHPF. Potentiodynamic polarization scans were used to determine the corrosion potential of the coating, and this was used to calculate the driving force for cathodic protection using the difference in corrosion potential between the coating phases and the substrate. It was found that only Γ-Fe3Zn10 provided robust cathodic protection to both steel substrates, and the driving force for cathodic protection was lower for the coated DHPF 2.5%Mn steel. Galvanostatic scans were used to evaluate dissolution kinetics of coating phases. Robust cathodic protection was provided by the galvanized coating for austenitization times of 30 - 120 s for the 2%Mn substrate and 30 - 60 s for the 2.5%Mn substrate. The duration that robust cathodic protection was provided was shortest at the wall of the U-shape part. This result was attributed to die wiping caused by DHPF, where the surface is smoothed by die friction. When there is less Г-Fe3Zn10 in the coating, such as at longer austenization times, surface Г-Fe3Zn10 was removed and an increased amount of α-Fe(Zn) is exposed, which does not provide robust cathodic protection. In addition, coating cracks form along α-Fe(Zn) grain boundaries after austenitization for 180 s on all examined regions of the U-shape part, allowing a greater surface area of the coating exposed to electrolyte, further increasing dissolution of the coating. / Thesis / Master of Applied Science (MASc)