Student Number : 9608998A - MSc dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / The history of flux compression is relatively short. One of the founders, a Russian physicist, Sakharov developed the idea of compressing a magnetic field to generate high magnetic fields and from this he also developed a generator to produce current impulses. Most of this initial work was performed in military research laboratories. The first open source literature became available in the 1960s and from there it has become an international research arena. There are two types of flux compression generators, field generators and current generators. These are discussed along with the basic theory of flux compression generators and related physics. The efficiency of generators is often quite low. However in many generators high explosives are used and because of their high energy density, the current or field strength produced is substantially greater then the initial source. This of course limits the locations possible for experimental work and subsequently limits the industrial applications of flux compression generators . This research presents a theoretical design for a non-explosive flux compression generator. The generator is designed to produce a current impulse for tests in laboratory and remote locations. The generator has the advantage of being non-destructive, therefore reducing costs, and allowing for repeatable experiments. The design also reduces the possibilities or many of the loss mechanisms.

Systemic lupus erythematosus (SLE) is a chronic multiorgan autoimmune disorder characterized by abundant immune complex (IC) deposition, with nephritis being a major cause of morbidity and mortality. Yet, IC deposition alone is not sufficient for disease development suggesting that additional factors dictate the propensity for developing target organ injury. Genome-wide association studies have identified polymorphisms in the leukocyte integrin Mac-1 (CD11b/CD18, ITGAM) that associate with lupus nephritis. Although Mac-1 promotes inflammation by triggering leukocyte recruitment and cytotoxic functions, there is emerging evidence that it may also serve protective roles under certain conditions. We demonstrate that Mac-1 deficiency in the context of the uniquely human FcgRIIA a receptor that binds IgG-IC, promotes susceptibility to lupus nephritis in two independent animal models. Analysis of renal tissue and intravital microscopy revealed that Mac-1 modulates neutrophil recruitment by FcgRIIA. The SLE-associated variant of Mac-1 rs1143679 (R77H), results in reduced Mac-1 functions, but the underlying mechanism remains undefined. CD18 integrin mediated adhesion is a multistep process that begins with affinity changes for ligand via transmission of allosteric signals. Moreover, mechanical forces (e.g. shear flow) paradoxically increase the lifetime of integrin-ligand bonds, referred to as "catch-bonds". Here, we show that expression of Mac-1 R77H on neutrophils, and blocking antibodies to the extracellular b-propeller domain in which it resides, markedly impairs Mac-1 adhesion to ligand under shear flow. R77H expressing cells exhibit a shift in equilibrium towards a bent conformation, a lower affinity and on- and off- rate for ligand and an inability to form catch-bonds. Additional mutants and activating antibodies reveal that R77H prevents allosteric signal transmission to the aI-domain required for productive ligand binding.

Submitted by MARIA LIANEIDE SOUTO ARAUJO (lianeide.araujo@yahoo.com.br) on 2017-07-07T20:58:01Z No. of bitstreams: 1 tesecomfichacatalográfica.pdf: 13753526 bytes, checksum: 5453fe7b9a5de95dfb08fef7ef8a55f7 (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-07-13T18:28:17Z (GMT) No. of bitstreams: 1 araujo_mls_dr_rcla.pdf: 13753526 bytes, checksum: 5453fe7b9a5de95dfb08fef7ef8a55f7 (MD5) / Made available in DSpace on 2017-07-13T18:28:17Z (GMT). No. of bitstreams: 1 araujo_mls_dr_rcla.pdf: 13753526 bytes, checksum: 5453fe7b9a5de95dfb08fef7ef8a55f7 (MD5) Previous issue date: 2017-03-10 / A Fundação Casa Grande-Memorial do Homem Cariri (FCG-MHK), “Casa do Patrimônio” da Chapada do Araripe é o atrativo turístico mais visitado na sede de Nova Olinda, município do Cariri, região sul do Ceará. No Mapa do Programa de Regionalização do Turismo - Roteiros do Brasil de 2006, Nova Olinda ocupa uma posição de destaque, como um dos “65 Destinos Indutores do Desenvolvimento Turístico Regional”. O objetivo da pesquisa foi investigar o trabalho da FCG-MHK entre 2006 e 2016, em relação ao patrimônio cultural e ao turismo do lugar, contextualizado no espaço regional do Cariri. Optamos pela abordagem teórico-metodológica da nova geografia cultural. Articulamos a pesquisa bibliográfica com a documental e a observação participante. Os dados primários foram cole tados por meio de conversas informais, entrevistas semiestruturadas e registros fotográficos. A interpretação e análise do material nos permitiu inferir os seguintes aspectos: 1) a salvaguarda do patrimônio cultural do Cariri é a matriz estruturante do trabalho da FCG-MHK desde a sua instalação, em 1992; 2) o turismo é tratado de modo comunitário como alternativa de geração de renda para as famílias das pessoas vinculadas à FGC-MHK; 3) para o grupo social dos residentes-anfitriões da FCG-MHK, o turismo pressupõe a interação e a troca de saberes e fazeres entre turistas e residentes; 4) parte majoritária dos turistas atraídos para Nova Olinda, por meio da FCG-MHK, busca aprendizagem, formação, enriquecimento e trocas culturais; convivência com os residentes, características identificadoras do turismo cultural; 5) O trabalho da FCG-MHK resultou em benefícios diretos para melhoria da estrutura urbana da sede de Nova Olinda; Constatamos, no entanto, que malgrado todos os desafios, a FCG-MHK consegue executar um trabalho de elevado valor sociocultural há 24 anos, aliando a salvaguarda do patrimônio cultural com geração de renda para uma parcela significativa da população na sede do município, constituindo-se um núcleo de resistência ao modelo hegemônico de distribuição dos resultados econômicos do turismo. / The Casa Grande Foundation - People from Kariri Memorial (FCG-MHK), “Casa do Patrimônio” (Home of the Heritage) from Araripe Plateau is the most visited touristic attraction in Nova Olinda, a city in Cariri, located in the South of the State of Ceará. In the Regional Tourism Program Map – Brazil Destinations from 2006, Nova Olinda featured as one of the “65 Destinies inducers of Regional Touristic Development”. The objective of this survey was to investigate the work of the FCG-MHK between 2006 and 2016, in relation to the cultural heritage and local tourism, contextualized in the region of Cariri. We chose the theoretical-methodological approach from the new cultural geography. We articulated the bibliographical research with documents and participating observation. The primary data was collected by means of informal conversations, semi-structured interviews and photographs. The interpretation and analysis of the material led us to infer the following aspects: 1) The safekeeping of the cultural heritage from Cariri has been the main objective of the FCG-MHK since its creation in 1992; 2) The tourism is dealt in a community way as an alternative of income for the families in the FGC-MHK; 3) For the residents-hosts form the FCG-MHK, the tourism considers the interaction and knowledge and know-how exchange between themselves, visitors and tourists; 4) The majority of the tourists attracted to Nova Olinda through FCG-MHK, look for learning, formation, and cultural and enrichment exchanges; interaction with the residents, identifying characteristics of the cultural tourism; 5) The work form the FCG-MHK resulted in direct benefits to improve the urban structure of Nova Olinda; We found the even with all the challenges, the FCG-MHK has been able to make a high level job regarding the social cultural value in the past 24 years, joining protection and safekeeping the cultural heritage of Cariri with an informal education and income generation for a great deal of the population in the city, constituting as a resistance cell to the hegemonic model of distribution of touristic economic results.

<p>Aeronautical products additively manufactured by Selective Laser Melting (SLM), are known to have fatigue properties which are negatively impacted by porosity defects, microstructural features and residual stresses. Little research is available studying these phenomena with respect to the short fatigue crack growth (FCG) inconsistency problem, the large focus being on the long FCG. This thesis seeks to add useful knowledge to the understanding of the mechanisms for short crack growth variability in SLM manufactured Ti-6Al-4V, with the two variables for the process conditions and build directions investigated. An in-situ FCG investigation using x-ray synchrotron computed micro-tomography (μXSCT) was used to visually observe and quantify the short crack path evolution. Crack growth, deflections and porosity interactions were noted and discussed in relation to microstructure, build layer thickness and build layer orientation. A novel use of in-situ energy dispersive x-ray diffraction (EDD) was able to show the lattice strains evolving as a propagating crack moved through a small region of interest. The results presented show the ability to reliably obtain all six elastic strain tensor components, and interpret useful knowledge from a small region of interest. </p> <p> </p> <p>There are conflicting views in literature with respect to the damage tolerance behavior of as built SLM manufactured Ti-6Al-4V. In the 2018 review by Agius et al., the more prominent studies were considered with Leuders et al. showing the highest long FCG rates for cracks parallel to the build layer and Cain et al. showing cracks propagating through successive build layers as highest [1]–[3]. Cain et al. and Vilaro et al. report significant anisotropy in long FCG for different build orientations whereas Edwards and Ramulu present similar FCG behavior for three different build directions [2]–[5]. Kruth et al. concluded that for optimized build parameters without any (detectable) pores, the building direction does not play a significant role in the fracture toughness results [6]. All of the mentioned literature reported martensitic microstructures and the presence of prior grain structures for as built SLM Ti-6Al-4V.</p> <p> </p> <p>No studies to the authors knowledge have considered the short FCG of SLM manufactured Ti‑6Al‑4V and its implications to the conflicting damage tolerance behaviors reported in literature [1]. In this work small cross-sectional area (1.5 x 1.5 ) samples in two different build conditions of as built SLM Ti-6Al‑4V are studied. The short FCG rate of three different build directions was considered with cracks parallel to the build layers shown to be the most damaging. The microstructure and build layer are shown to be the likely dominant factors in the short FCG rate of as built Ti-6Al-4V. In terms of porosity, little impact to the propagating short crack was seen although there is local elastoplastic behavior around these defects which could cause toughening in the non-optimized build parameter samples tested. The fracture surfaces were examined using a Scanning Electron Microscope (SEM) with the results showing significant differences in the behavior of the two build conditions. From the microindentation hardness testing undertaken, the smooth fracture surface of the optimized sample correlated with a higher Vickers Hardness (VH) result and therefore higher strength. The non-optimized samples had a ‘rough’ fracture surface, a lower VH result and therefore strength. Furthering the knowledge of short FCG in SLM manufactured Ti-6Al-4V will have positive implications to accurately life and therefore certify additive manufactured aeronautical products.</p>

No description available.

No description available.

Main extrinsic and intrinsic modifiers factors of crack growth rate in AA7050-T7451 were assessed in order to provide tools for aeronautical structures designers. These tools cover most necessary information to project aircraft\'s structures using the studied alloy, under damage tolerance philosophy. The experimental methodology consisted of use CT specimens, on TL and LT rolling direction to test its behavior under different conditions of stress ratio, force waveform, and the environment. The stress ratio values were 0.1 and 0.5, the force waveform used were sine and trapezoidal or Dwell under normal air laboratory conditions and salt fog 3.5%NaCl weight in order to simulate the marine environment. In Dwell tests, results were checked with the electrical potential drop technique (DCPD) in addition to the crack opening displacement (COD) method. Using the Walker coefficients, calculated on the present research, could be projected accurately the crack propagation behavior on Paris region and do fatigue life predictions using da/dN and S-N diagrams for different stress ratio values. The corrosion environment increases both crack growth rate and &Delta;Kth due to oxides formation on the crack path that generates a crack closure effect. Dwell carrying makes decrease the crack growth rate by decreasing the slope of the Paris line on log (da/dN) versus log (&Delta;K) curve, instead of shifting down the line as occurs on titanium alloys. Rolling direction change from LT to TL increase the FCG rate in both threshold and Paris region, where the rate change use to be small. / Os principais fatores modificadores extrínsecos e intrínsecos da taxa de propagação de trincas na liga AA7050-T7451 foram avaliados para fornecer subsídios para projetistas de estruturas aeronáuticas, com base na filosofía de tolerância ao dano. A metodologia experimental consistiu em ensaiar corpos de prova do tipo compact tension (CT) da liga nas direções de laminação TL e LT, para verificar seu comportamento sob diferentes razões de tensões, forma de onda e condição ambiente. Os valores de razão de tensão estudados foram 0,1 e 0,5, as formas de onda foram senoidal e trapezoidal ou de Dwell, em condições normais de laboratório, ao ar, e névoa salina 3,5% NaCl, em massa, para simular um ambiente marinho. No caso dos ensaios Dwell, os resultados foram conferidos pelo método de queda de potencial eléctrico (QPE), além do método de flexibilidade elástica. Usando os coeficientes de Walker calculados a partir dos resultados obtidos, pôde-se projetar com precisão o comportamento da propagação de trinca na região de Paris e prever a vida em fadiga usando os diagramas da/dN e S-N para diferentes valores da razão de tensões. O ambiente corrosivo aumenta tanto a taxa de propagação de trinca, quanto o valor de &Delta;Kth por causa da formação de óxidos na trajetória da trinca, que geram um efeito de fechamento sobre a mesma. Quanto à forma de onda, verificou-se que o carregamento Dwell diminui a taxa de propagação de trinca, diminuindo a inclinação das curvas log (da/dN) versus log (&Delta;K) na região de Paris, ao invés de deslocá-la paralelamente como ocorre com ligas de titânio. A mudança da direção de laminação de LT para TL aumenta a taxa de propagação de trinca por fadiga (PTF) tanto na região de threshold, quanto na região de Paris, onde a mudança de taxa é pequena.

Main extrinsic and intrinsic modifiers factors of crack growth rate in AA7050-T7451 were assessed in order to provide tools for aeronautical structures designers. These tools cover most necessary information to project aircraft\'s structures using the studied alloy, under damage tolerance philosophy. The experimental methodology consisted of use CT specimens, on TL and LT rolling direction to test its behavior under different conditions of stress ratio, force waveform, and the environment. The stress ratio values were 0.1 and 0.5, the force waveform used were sine and trapezoidal or Dwell under normal air laboratory conditions and salt fog 3.5%NaCl weight in order to simulate the marine environment. In Dwell tests, results were checked with the electrical potential drop technique (DCPD) in addition to the crack opening displacement (COD) method. Using the Walker coefficients, calculated on the present research, could be projected accurately the crack propagation behavior on Paris region and do fatigue life predictions using da/dN and S-N diagrams for different stress ratio values. The corrosion environment increases both crack growth rate and &Delta;Kth due to oxides formation on the crack path that generates a crack closure effect. Dwell carrying makes decrease the crack growth rate by decreasing the slope of the Paris line on log (da/dN) versus log (&Delta;K) curve, instead of shifting down the line as occurs on titanium alloys. Rolling direction change from LT to TL increase the FCG rate in both threshold and Paris region, where the rate change use to be small. / Os principais fatores modificadores extrínsecos e intrínsecos da taxa de propagação de trincas na liga AA7050-T7451 foram avaliados para fornecer subsídios para projetistas de estruturas aeronáuticas, com base na filosofía de tolerância ao dano. A metodologia experimental consistiu em ensaiar corpos de prova do tipo compact tension (CT) da liga nas direções de laminação TL e LT, para verificar seu comportamento sob diferentes razões de tensões, forma de onda e condição ambiente. Os valores de razão de tensão estudados foram 0,1 e 0,5, as formas de onda foram senoidal e trapezoidal ou de Dwell, em condições normais de laboratório, ao ar, e névoa salina 3,5% NaCl, em massa, para simular um ambiente marinho. No caso dos ensaios Dwell, os resultados foram conferidos pelo método de queda de potencial eléctrico (QPE), além do método de flexibilidade elástica. Usando os coeficientes de Walker calculados a partir dos resultados obtidos, pôde-se projetar com precisão o comportamento da propagação de trinca na região de Paris e prever a vida em fadiga usando os diagramas da/dN e S-N para diferentes valores da razão de tensões. O ambiente corrosivo aumenta tanto a taxa de propagação de trinca, quanto o valor de &Delta;Kth por causa da formação de óxidos na trajetória da trinca, que geram um efeito de fechamento sobre a mesma. Quanto à forma de onda, verificou-se que o carregamento Dwell diminui a taxa de propagação de trinca, diminuindo a inclinação das curvas log (da/dN) versus log (&Delta;K) na região de Paris, ao invés de deslocá-la paralelamente como ocorre com ligas de titânio. A mudança da direção de laminação de LT para TL aumenta a taxa de propagação de trinca por fadiga (PTF) tanto na região de threshold, quanto na região de Paris, onde a mudança de taxa é pequena.