Made available in DSpace on 2017-07-10T14:17:17Z (GMT). No. of bitstreams: 1 aniele_ tomadon.pdf: 1946569 bytes, checksum: 9b3b2e8ea732badbc11f5df6fa34a988 (MD5) Previous issue date: 2016-02-01 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Paracoccidioidomycosis (PCM), caused by the dimorphic fungus Paracoccidioides brasiliensis, is one of the most prevalent systemic mycosis in Latin America. Infection can occur accidentally through direct inoculation or mainly through inhalation of propagules of P. brasiliensis, which are installed initially in the lungs and can spread to organs and tissues of the host. In the acute form of the disease the major clinical manifestation is the febrile lymphoproliferative syndrome, occurring osteoarticular involvement; the same for the chronic form, in which 60% of cases, bone and joint changes usually treated for extended periods with conventional antifungal agents. Drug therapy is the most widely used to treatment the disease, however, high costs, poor adherence to treatment and adverse side effects, take the need to search for alternative therapies such as photodynamic (PDT), which has low cost and toxicity, local action and does not induce resistance to microorganisms. In vitro studies have shown positive results of PDT against various fungi, but there are no in vivo reports on its action in the control of P. brasiliensis. In this sense, the present study aimed to evaluate the PDT response in an experimental model of arthritis by P. brasiliensis. For this purpose, male Wistar rats (n = 42) were divided into groups submitted to inoculation with P. brasiliensis and PBS (control) in the right knee joint. After the development of arthritis, the mice were treated from the eighth to the eleventh day to the therapy: Groups L40 and L120 laser treated at dosages of 40 and 120 J/cm2, AM group treated with the photosensitizer methylene blue and PDT40 and PDT120 groups treated with PDT at doses of 40 and 120 J/cm2. The laser and AM therapies were used individually as a control for PDT. The groups were evaluated: edema, by measuring the lateral-lateral diameter of the joint; the intensity of arthritis, for histopathology and titration of anti-gp43 antibody by ELISA. The results showed that the edema formation was lower in the groups treated with PDT 40 and 120 J/cm2 (p = 0.8359 and p = 0.7167, respectively). The analysis of the intensity of arthritis as assessed by histopathology showed that the group treated with PDT 120 J/cm2 had the lowest morphological changes in the joint. Titration of anti-gp43 antibodies, showed the highest production of specific antibodies in the yeast group, but the differences were not significant when comparing the groups. Thus, the morphological evidence of normal tissue recovery aspects, the joint subjected to PDT 120 J/cm2, revealed the potential use of this therapy in reducing arthritis caused by P. brasiliensis / A Paracoccidioidomicose (PCM), causada pelo fungo dimórfico Paracoccidioides brasiliensis, é uma das micoses sistêmicas de maior prevalência na América Latina. A infecção pode ocorrer acidentalmente por inoculação direta ou, principalmente, através da inalação de propágulos de P. brasiliensis, que se instalam inicialmente nos pulmões e podem se disseminar para órgãos e tecidos do hospedeiro. Na forma aguda da doença a principal manifestação clínica é a síndrome linfoproliferativa febril, podendo ocorrer acometimento osteoarticular; o mesmo para a forma crônica, onde em 60% dos casos há alterações ósseas e articulares, geralmente tratadas por longos períodos com antifúngicos convencionais. A terapia medicamentosa é a mais utilizada para o controle da doença, entretanto, custos elevados, baixa adesão ao tratamento e efeitos colaterais adversos, levam a necessidade de se pesquisar terapias alternativas, como a fotodinâmica (TFD), que apresenta baixo custo e toxicidade, ação local e não induz resistência aos microorganismos. Estudos in vitro têm demonstrado resultados positivos da TFD contra diversos fungos, mas não existem relatos in vivo sobre sua ação no controle de P. brasiliensis. Nesse sentido, o presente estudo objetivou avaliar a resposta da TFD em modelo experimental de artrite por P. brasiliensis. Para tanto, ratos Wistar machos (n=42), foram distribuídos em grupos submetidos à inoculação de P. brasiliensis e PBS (controle) na articulação do joelho direito. Após o desenvolvimento da artrite, os grupos foram tratados, do oitavo ao décimo primeiro dia com as terapias: grupos L40 e L120 tratados com laser nas dosagens de 40 e 120 J/cm2, grupo AM tradado com o fotossensibilizador azul de metileno e grupos TFD40 e TFD120 tratados com TFD nas dosagens de 40 e 120 J/cm2. Os tratamentos com laser e AM foram utilizados de forma individual como controle para a TFD. Nos grupos foram avaliados: o edema, através da medida do diâmetro látero-lateral da articulação; a intensidade da artrite, por exame histopatológico e a titulação do anticorpo anti-gp43, por ELISA. Os resultados mostraram que, a formação do edema foi menor nos grupos tratados com TFD 40 e 120 J/cm2 (p=0,8359 e p=0,7167, respectivamente). A análise da intensidade da artrite, revelou que o grupo tratado com TFD 120 J/cm2 apresentou as menores alterações morfológicas na articulação. A titulação de anticorpos anti-Gp43, demonstrou a maior produção de anticorpos específicos no grupo levedura, porém as diferenças não foram significativas na comparação entre os demais grupos. Assim, as evidências morfológicas de recuperação de aspectos teciduais normais, na articulação submetida a TFD 120 J/cm2, revelaram o potencial uso desta terapia na redução da artrite causada por P. brasiliensis.

This work develops and examines design strategies for reducing the stiffness of 3D-printed compliant mechanisms. The three aspects of a flexure that determine its stiffness are well known: material, boundary conditions, and geometry. In a highly constrained design space however, flexure stiffness may remain unacceptably high even while arriving at the limits of design constraints. In this work, changes to geometry and boundary conditions are examined that lead to drastically reduced stiffness behavior without changing flexure thickness, width, or length. Changes to geometry can result in very complex mechanisms. However, 3D printing enables almost arbitrarily complex geometries. This dissertation presents three design strategies for stiffness reduction: static balancing, lattice flexures, and compound joints. Static balancing refers to changes in the boundary conditions that result in a near-zero net change in potential energy storage over the useful deflection of a flexure. In this work, I present a method for static balancing that utilizes non-dimensional parameters to quickly synthesize a joint design with stiffness reduced by nearly 90%. This method is not only simple and straightforward, it is applicable to a wide range of flexure topologies. The only requirements on the joint to be balanced are that it must be approximated as a pin joint and torsion spring, and it must have a well-understood stiffness when subjected to a compressive load. Lattice flexures result from modifications to geometry that reduce cross-sectional area without changing width or thickness. However, the reduction in stiffness is greater than the reduction in cross sectional area. This can occur because the bending load is now carried by beams partially in torsion. Two lattice geometries are proposed and analyzed in detail using analytic and numeric techniques. It is shown that the off-axis stiffness behavior of lattice flexures can be better than that of conventional blade flexures while bending stiffness is reduced >60%. Compound joints are those that consist of arrays of flexures arranged co-axially. This arrangement provides increased range of motion, generally decreased stiffness, and improved stability. Additionally, a method is herein presented to reduce the parasitic center shift of a compound joint to nearly zero at a specified deflection. The penultimate chapter demonstrates how all three strategies can be used together, and includes new results to facilitate their combination.

Le collage structural se présente comme une alternative intéressante aux méthodes classiques d'assemblages par ajout d’éléments mécaniques pour alléger les structures aéronautiques. Cependant, l'utilisation de cette méthode soulève de nombreuses questions en termes de conception, caractérisation ou modélisation. Ce travail, à fort caractère expérimental, visent deux grands objectifs : (i) sélectionner les moyens d'instrumentation les plus adaptés pour la caractérisation du comportement jusqu'à rupture des assemblages collés et (ii) prédire le comportement des assemblages collés à partir d'une caractérisation et d'une modélisation complète sous chargements quasi-statiques bi-axiaux, en utilisant un type d’essai simple et industrialisable. Dans un premier temps, pour atteindre ces objectifs, un nouvel essai appelé Scarf modifié a été proposé, afin de caractériser le comportement mécanique du joint de colle, en minimisant les effets de bord par la présence de becs. La deuxième partie de la thèse porte sur le développement d'une stratégie de caractérisation simplifiée du comportement de joint de colle, sous certaines hypothèses (états de contraintes/déformations, continuité du champ de contraintes). Cette stratégie a permis d'obtenir le comportement intrinsèque de l’adhésif sous la forme de courbes contraintes/déformations. La dernière partie abordée dans ces travaux, s'intéresse quant à elle à l'identification et la sélection des moyens de métrologie les plus appropriés, pour accompagner la caractérisation expérimentale. / Today, structural bonding presents an interesting alternative to conventional methods of assembly, in order to reduce the weight within aeronautical structures. However, the use of this method raises many questions in terms of design, characterization or modeling. This work presents a robust experimental work, aiming two main objectives: (i) select the most suitable instrumentation for the characterization of the behavior of bonded joints up to failure and (ii) predict the behavior of bonded joints from complete characterization and modeling under quasi-static bi-axial loading, using a simple test, directly integrated to industry. In a first stage, to achieve this goal, modified Scarf test has been proposed to characterize the mechanical behavior of adhesive joints. This type of specimen allows applying multiaxial loadings without having high-stress concentrations near the edges. The second part of the thesis deals with the development of a strategy for simplifying the characterization of a bonded joint using some hypotheses (stress/strain states). This strategy allows obtaining the intrinsic behavior of the adhesive in the form of the stress/strain curves. The last part of this work deals with the identification and selection of the most appropriate instrumentation systems in the experimental characterization.

In this thesis I have studied how hypermobile joints affect my violin playing and tried to to find solutions how to cope with hypermobility.  The purpose is to find tools how to change my left-hand technique so that I can play Bach´s Fugue from Solo sonata in g minor in my master concert without pain in my 4th finger and without tension in my left-hand. The goal is to find a way to play with hypermobile joints so that my technique will serve the music in the best possible way.  The biggest questions are: what hypermobility is, how can I cope with it, how to play more relaxed and how to develop a better support for my left-hand little finger, 4th finger.  The thesis will first focus more on the theoretical side of hypermobility in order to get better understanding of what hypermobilty is and how it might affect a violinist. Then I will get more into the aspects of violin playing and my process. After this process I noticed that working with hypermobile joints is a lifelong process. In order to have a good left-hand technique while having hypermobile joints it is crucial to have good muscle control and awareness. The most important thing is to find the right tools that work for yourself while trying to cope with hypermobility.

Embedded active and passive devices has been increasingly used by in order to integrate more functions inside the same or smaller size device and to meet the need for better electrical performance of the component assemblies. Solder joints have been used in the electronic industry as both structural and electrical interconnections between electronic packages and printed circuit boards (PCB). When solder joints are under thermal cyclic loading, mismatch in coefficients of thermal expansion (CTE) between the printed circuit boards and the solder balls creates thermal strains and stresses on the joints, which may finally result in cracking. Consequently, the mechanical interconnection is lost, leading to electrical failures which in turn causes malfunction of the circuit or whole system. When a die is embedded into a substrate, Young's modulus of the die is larger than one of the core of the substrate and the CTEs of the die is smaller than those of the substrate. As a result, mismatch in coefficients of thermal expansions (CTE) between the substrate with the embedded device and the solder balls may increase. In the present study, finite element method (FEM) is employed to find out the stress and strain distribution of ball grid array(BGA) solders under thermal cycling. The ANAND model for viscoplasticity is employed for this purpose.

Solder joints serve as both mechanical and electrical connections between elements in a package. They are subjected to shear strains generated as a result of the different behaviors of the elements in the package (tension and compression) due to the differences in coefficients of thermal expansion during service conditions. Some of the causes of solder joint failures are due to the following: Vibration: small rapid displacements of parts of the assembly. This is not necessarily an issue with electronic components but larger parts like automobiles. Humidity: the package being exposed to water or ionic species can undergo corrosion if an electrical bias exists resulting in electrical opens or electrical shorts if the corrosion products are electrically conductive. Thermal Aging: this occurs during the lifetime of the solder interconnects, the package can be exposed to high ambient temperature or high dissipated heat during use. The micro-structure of the solder joint becomes more coarse and brittle. Mechanical Shock: the package undergoes shock during a short term exposure to high loads. Thermo-mechanical fatigue: this type of failure arises as a result of the solder joints going through cyclic strains, due to different coefficients of thermal expansion of individual components in the package during service. The most prevalent long-term reliability issues that can cause interconnect failure are thermal aging and thermo-mechanical fatigue. This study aims to evaluate the reliability of solder joints using finite element method, considering solder joint failure due to thermo-mechanical fatigue. Three variations of the BGA (Ball Grid Array) package are evaluated using the finite element analysis. The SAC305 series lead (pb) free alloy of 96.5% tin, 3% silver, and 0.5% copper is employed for this study.

The use and implementation of adhesive joints for space structures is necessary for incorporating fiber-reinforced composite materials. Correct modeling and design of cylindrical adhesive joints can increase the dimensional stability of space structures. The few analytical models for cylindrical adhesive joints do not fully describe the displacement or stress field of the joint. A two-dimensional axisymmetric finite element model for the design and analysis of adhesive joints was developed. The model was developed solely for the analysis of cylindrical adhesive joints, but the energy techniques used to develop the model can be applied to other types of joints as well. A numerical program was written to solve the system of equations [K]{d}={R} for the unknown displacements {d}. The displacements found from the program are used to design cylindrical adhesive joints based on dimensional stability. Stresses were calculated from the displacements for comparison with analytical models. The cylindrical joints were assumed to remain within the linear elastic region and no failure criteria was taken into account. The design process for cylindrical joints was developed based on dimensional stability. The nodal displacements found from the finite element model were used in the optimization of geometric parameters of cylindrical joints. The stacking sequence of the composite, the bond length, and the bond thickness were found to have the greatest impact on dimensional stability. Other factors that were found to further reduce the maximum displacements are the implementation of 0° and 90° laminas, the isotropic cylinder thickness, tapering of the isotropic cylinder, and the inside radius of the cylindrical joint. This axisymmetric finite element model is beneficial in that a cylindrical joint can be designed before any testing is performed. The results and cases in this thesis are generalized in order to show how the design process works. The model can be used in conjunction with design requirements for a specific joint to reduce the maximum displacements below any specified operating requirements. The joint is dimensionally stable if the overall displacements meet specific design requirements.

Earthen dams are often built into bedrock abutments and on bedrock foundations. Bedrock joints naturally occur in bedrock materials. These bedrock joints create voids for ground water to pass through. Historically earthen dams were sometimes built in direct contact with the bedrock joints, causing a contact point between the soil of the dam and the flowing water. It has been engineering practice to place grout into exposed bedrock joints for some time now. However, soil is not always cleaned out of bedrock joints before they are grouted, which leaves a weakness for water to push through. The purpose of this study is to understand the point at which water flowing through bedrock joints will erode soil from the earthen dam embankment. The information of how much soil is eroded away in an amount of time is also crucial to the scope of this study. The goals of this study were accomplished by building a physical model or apparatus of an earthen dam embankment on top of a simulated bedrock joint. Different soil types were tested in the apparatus to start a database of information about erosion rates of the soil along the bedrock joint and embankment interface. These results will be used to start a database for organizations that assign probabilities of dam failures. The purpose of the study is not to indicate when dams will fail, but to help with assigning probabilities of the likelihood of a serious problem being caused from this type of mechanism presented in this study.

Abstract not available

Abstract not available