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Os desenvolvimentos de novos motores têm resultado no aumento constante dos carregamentos mecânicos e térmicos dos componentes. Além de estarem expostos a condições desfavoráveis ao desgaste, os novos componentes do motor devem garantir desempenho similar, ou muitas vezes superior, aos dos componentes atuais. Para os anéis de pistão, o desempenho é dado pela sua capacidade de vedação e raspagem, que podem ser mensurados em motor pelos resultados de consumo de óleo lubrificante (COL) e fluxo de gases para o cárter (blow-by). Sendo assim, a proposta desse trabalho foi a de avaliar-se a influência do tratamento superficial a laser para endurecimento da pista de desgaste do anel de pistão de segundo canalete, em termos do desempenho de vedação e raspagem. Foram comparados dois protótipos, utilizando como padrão um anel de pistão de produção corrente, comercialmente fornecido a clientes. O efeito do tratamento térmico a laser nos anéis foi avaliado em relação a distorções dimensionais. Após isto, foram realizados testes tribológicos de bancada com o objetivo de conhecer o comportamento do anel depois do tratamento laser. De maneira geral o tratamento superficial por laser na superfície de anéis de pistão mostraram resultados significativos no aspecto aumento de dureza, com alguns deméritos no aspecto dimensional que pode interferir na boa funcionalidade do sistema tribológico anel lubrificante cilindro. / The new engine developments are providing engine mechanical and thermal loads increase on the components. Besides the unfavorable wear conditions, the components should provide similar or improved performance compared with current baselines. For piston rings, the performance is given by the ring capacity of sealing and scrapping. These performances can be measured in a engine by the results of lube oil consumption (LOC) and Blow-by. So, the proposal of this work is to evaluate the influence of laser hardening on the second ring wear and verify the sealing and scrapping performance. It was compared two prototypes, being as parameter the current piston ring supplied to customer. Firstly, it was compared the dimensional of the laser hardening effect. After that, it were tested these prototypes in bench tests in order to know the ring performance after laser hardening. In general terms, the superficial treatment by laser on the piston rings surface have showed significant results in the hardness aspects, with some demerits in the dimensional aspect that can interfere in the good functionality of the tribological system, piston rings lubricant cylinder liner.

Ditiocarbamatos (DTC) tem uma vasta gama de aplicação. Na indústria são usados como ativos para vulcanização da borracha; lubrificantes e anticorrosivos para trabalhos em alta pressão. Na medicina são estudados como potenciais inibidores do fator nuclear kappa β (NF-KB) e da protease do HIV-1; além da aplicação como indutores da apoptose em vários tipos de células carcinogênicas e como agentes antimicrobianos e antifúngicos. Derivados cíclicos de ditiocarbamatos são capazes de formar extensos arranjos no estado sólido mantidos por ligações de hidrogênio, interações do tipo π - π, interações metal - π e interações de van der Waals. No presente trabalho, determinou-se a natureza dessas interações em ditiocarbamatos derivados da própria amina substituinte e de metais alcalinos. Foram calculados mapas de potencial eletrostático molecular e momentos dipolo, a fim de entender quais fatores regem o empacotamento cristalino. Os átomos de enxofre nessas moléculas apresentam ligações mono ou bidentadas e ligações hidrogênio intramoleculares, que formam arranjos poliméricos. Essas interações são fracas, com distâncias da ordem da soma de seus raios de van der Waals, semelhante ao grafite. / Dithiocarbamates (DTC) are applied in several areas such as agricultural products, pesticides and repellents; industry, as additives for vulcanization of rubber; organic synthesis as precursors; chelating agents; lubricants and antiwear at high pressure. In medical fields, they have also been applied as a potential nuclear factor kappa B (NF - κB) inhinitor; transcription factor heat shock factor 1 (HSF1); HIV-1 protease inhibitor; co-adjuvant agent in the treatment of opportunistic infections in AIDS patients; inducer of apoptosis activity in several types of cancer cells, e.g. renal cell carcinoma, breast cancer; besides being great antimicrobicial and antifungal agents. Cyclic dithiocarbamate derivates are capable of forming extended hydrogen bonded arrays in the solid state. They are kept in the solid state by hydrogen bonds, π - π interactions stacking, π - metal interactions and van der Waals interactions. This work presents eight ditihiocarbamates derivates, their syntheses and recrystallization. The analysis of the dithiocarbamates salts was performed by X-ray diffraction which has gave the influence of the ligand in the crystalline arrangement, and molecular electrostatic potential maps, by DFT calculations. The sulphur atoms in these molecules have mono or bidentate bonds and intramolecular hydrogen bonds, forming polymeric arrangements. These interactions are weak, with distances of the order of the sum of their van der Waals radii, similar to graphite.

Há pouca literatura acerca dos valores de referência das medidas de dispersão na pesquisa avícola bem como a relação entre tais medidas e o número de aves por repetição e número de repetições e ainda os efeitos de fatores intrínsecos à pesquisa sobre a variabilidade experimental. Com isso, objetiva-se estabelecer faixas de classificação das medidas de dispersão, bem como a relação entre medidas e o número de aves por repetição, número de repetições por tratamento, número de aves abatidas para avaliação de carcaças, número de ovos coletados para análises de qualidade e os efeitos de fatores intrínsecos à pesquisa sobre a variabilidade experimental. Os dados foram obtidos nos trabalhos publicados nos periódicos com classificação Qualis/CAPES nos estratos A1, A2, B1, B2 e B3, na área de zootecnia. Para a determinação das faixas de classificação das medidas de dispersão. Os dados foram correlacionados através da correlação de Spearman, dados qualitativos foram comparados pelo teste de Kruskal-Wallis. As faixas de classificação de coeficientes de variação podem ser utilizadas como balizador da qualidade e confiabilidade dos dados de experimentos com poedeiras comerciais e frangos de corte. A fase de vida ou estágio produtivo de poedeiras e frangos de corte devem ser levados em consideração na comparação de resultados experimentais. O erro padrão da média varia bastante nos parâmetros produtivos de poedeiras e frangos de corte e parece não ser uma medida de dispersão indicada para se comparar a precisão de diferentes experimentos, as suas faixas de classificação servem como referencial da frequência com que se encontra resultados. Coeficientes de variação e erros padrão da média de parâmetros produtivos de frangos de corte e de poedeiras comerciais são menores quanto maior o número de repetições e de aves por repetição. As aves amostradas para o abate nas avaliações de carcaça de frangos de corte devem apresentar o peso médio da parcela. O número de aves amostradas não influencia a variabilidade experimental. Os dias de amostragem para análises de qualidade de ovos não influenciam a variação aleatória. O número ideal de ovos amostrados está entre quatro e cinco ovos por repetição. Em frangos de corte a variabilidade aleatória para variáveis de produção são maiores para aves da linhagem Ross do que para aves da linhagem Cobb. Lotes mistos de frangos de corte apresentam maior variação de ganho de peso do que lotes de machos na fase de criação de um a 21 dias de idade. O rendimento de carcaça e a porcentagem de gordura abdominal apresentam menor variabilidade aleatória em lotes mistos do que em lotes de frangos machos. Para frangos de corte não há efeitos aleatórios que possam aumentar a variabilidade experimental em função da área disponível por ave. Para poedeiras quanto maior o período experimental menor tende a ser a variação aleatória. Poedeiras brancas apresentam menor variação aleatória dos parâmetros produtivos do que poedeiras vermelhas. O coeficiente de variação de parâmetros produtivos de poedeiras comerciais aumenta com o aumento da área disponível por ave. / There is little literature on the reference values of spread measures in poultry research and the relationship between such measures and the number of birds per replicate and number of replicates and even the effects of intrinsic factors to research on experimental variability. The aim of this research is to establish ranges for the classification of spread measures, and the relationship between measurements and the number of birds per replicate, number of replicates per treatment, number of birds slaughtered for carcass evaluation, number of eggs collected for quality analysis and impact of research intrinsic factors on experimental variability. The data were obtained in papers published in journals with Qualis/CAPES classification in strata A1, A2, B1, B2 and B3, in the area of animal science. To determine the classification of the spread measures. The data were correlated by Spearman correlation, qualitative data were compared using the Kruskal-Wallis test. The classification ranges of coefficients of variation can be used as an indicator of the quality and reliability of data from experiments with laying hens and broilers. The age or production stage of laying hens and broilers should be considered in the comparison of experimental results. The standard error of means varies greatly in production parameters of laying hens and broilers and seems not to be a measure of dispersion indicated to compare the accuracy of different experiments, their classification ranges serve as a frequency reference which it is results. Coefficients of variation and standard error of means of production parameters of broilers and laying hens are smaller the greater the number of repetitions and birds per replicate. The birds sampled for slaughter in assessing carcass of broilers must present the average weight of the replicate. The number of birds sampled does not influence the experimental variability. The days of sampling for quality analysis of eggs did not influence the random variation. The ideal number of eggs sampled is between four and five eggs per replicate. In broilers random variability for production variables are higher for Ross than for Cobb broilers. Straight run broilers exhibit greater variation in weight gain than lots of males in the creation phase of 1 to 21 days old. The carcass yield and abdominal fat have less random variability in straight run broilers than in lots of male chickens. No random effects that can increase experimental variability depending on the available area per bird on broilers. The higher is experimental period the greater is the random variations. White hens have less random variation in production parameters than brown hens. The coefficient of variation of productive parameters of laying hens increases with increasing the available area per bird.

Abstract This thesis will present an investigation into the variability of the maximum height of the ionospheric F2 layer, hmF2, with hour, season and latitude over the South African region. The dependence of hmF2 on solar and magnetic activity is also investigated. Data from three South African stations, namely Madimbo (22.4 S, 26.5 E), Grahamstown (33.3 S, 26.5 E) and Louisvale (28.5 S, 21.2 E) were used in this study. Initial results indicate that hmF2 shows a larger variability around midnight than during daytime for all the seasons. Monthly median values for hmF2 were used in all cases to illustrate the variability, and the International Reference Ionosphere (IRI) model has been used to investigate hmF2 predictability over South Africa. This research represents the initial steps towards a predictive model for the hmF2 parameter, with the long term aim of developing a new global hmF2 predictive model for the IRI. It is believed that this work will contribute signi cantly towards this aim through the understanding of the hmF2 parameter over a region that has not previously been investigated.

The degreework is based on an ancient technique called Reverse appliqué which is popular among the Kuna Indians with their Mola blouse and in Hmong textile art. There are various ways of using the technique. The basic method which I have been focusing my work on is where two or more layers are put together, the motif is then stitched through the layers either by hand or machine stitched, one or more layers is then cut open around the edges of the motif in order to reveal the next coming layer. I believe this technique has not been explored enough in terms of materials with various properties, layers,and textures resulting in the same generic surface expression. This work looks for various ways to use these elements in order to find new surface expressions. The result is a collection which suggests new ways of approaching the technique with a variety of mixed surface expressions such as by exploring various stitch tension into the technique, or by using the material itself as the keystone into the technique when creating the material and not only as one of the layers. More importantly the multiple material explorations that was conducted throughout this study indicates the amount of possibilities this technique has to offer for further exploration. It is also a suggestion to use materials that might not be considered as the right proper materials for streetwear, sportswear looks which in the end surprised me will the collection surprise you?

Under suitable conditions anodic metal oxidation leads to growth of complex porous structures. The initiation and growth of these structures is an interesting and challenging task for electrochemical modelling. One must identify chemical reactions in a multi-phase framework, derive a proper partial differential equations and solve them in time dependent domains. In this work, electrochemical model for the oxide growth in nano scales is presented. Physically motivated equations are formulated with precise mathematical meaning and existence of solutions is studied. Electrostatic potential fulfilling high-field conduction law and interfacial jump conditions is sought for. Numerical discretization is performed with the use of finite element method and free boundaries are tracked with characteristic level-set functions. Basic mechanism governing the growth of porous structures is given and numerical experiments are explained on it's basis. This thesis presents novel contributions to the electrochemical and mathematical picture of nanopores growth.

This dissertation consists of two articles. The first article describes an architecture for intelligent tutoring that focuses on modularity. This new architecture is based on Gibbons' layers theory for instructional design (2014). Splitting up the architecture for an intelligent tutor into layers allows different pieces to age at different rates which, in turn, allows the intelligent tutor to be adapted to new research and design theories. This architecture supports building intelligent tutoring services, nimble programs that can be assembled together to replicate the functions of intelligent tutoring without the expertise needed to create the services. Alternative architectures support building intelligent tutoring systems, monolithic programs that are less amenable to change and require immense expertise. The second article provides a proof of concept for the first services created under the layers theory. These two services create the building blocks of a domain and comprise one part of the content layer as described in the first article. The first service focuses on the task of key concept extraction whereas the second service focuses on prerequisite relationship extraction. These two tasks can provide the structure of the domain, particularly when it comes to domains that are more declarative in nature rather than procedural.

Housing is one of the most fundamental subjects of architecture, not just for the basic purpose of shelter, but for the place where vitality can be transcended to the people living in them. 'Housing' rather than 'house' marks the intersection between architecture and urban design and the simultaneous existence of the individual and collective. Housing is also a form of material culture. As such, it cannot be understood without studying the cultural and economic conditions of its production. - Rem Koolhaas, 'Conversations with students' With the gradual change in family structure, housing accommodations would be smaller as the family size reduces, however, common open space and active recreation of all types would be enlarged. This would be a greater opportunity to integrate urban with suburban environments - the town's cultural and employment opportunities would be within easy access to the countryside and to nature. "Architecture is an art filled with contradictions. The more we learned about these contradictions in architecture, the more they translate these contradictions into an antitheses; between discipline and freedom, between technology and environment, between modernity and tradition. But....discipline sets limits to freedom, yet it is also its container, the thing that gives it form. These two elements coexist and interact." - Herman Hertzberger, 'Lessons for students in Architecture' The meaning of space can be clarified as dualities; between public and private, light and shadow, positive and negative, horizontal and vertical, man-made and nature, and denotative and connotative. Space is transformed into characteristic place through these changes, layers and sequences of movement. It would undoubtedly guide urban growth toward a more humane living environment which can recover community space set against stereotypical architecture. / Master of Architecture