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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
581

Développement et modélisation d'éléments de prothèse pour la main / Development and modelisation of elements of prosthesis for the hand

Girod, Loïc 14 October 2010 (has links)
Comme toute articulation fonctionnelle, l’articulation interphalangienne proximale(IPP) est la cible de lésions ou de pathologies pouvant compromettre les fonctions globales de la main. Les principaux objectifs d’une arthroplastie digitale sont de restituer la fonction et la stabilité de l’articulation et de réduire ou supprimer la douleur de manière durable. Le présent travail de thèse porte sur le développement et la modélisation de deux concepts prothétiques pour l’articulation IPP : une prothèse semi-contrainte en alliage de nickel-titane et une prothèse de resurfaçage. Outre le travail de dimensionnement, des essais de fatigue et d’usure sont conduits sur les deux implants. Des études complémentaires à chaque concept sont présentées. Celles-ci portent en premier lieu sur la mise en forme et les traitements thermiques de la prothèse semi-contrainte accompagnées d’une étude de relargage de nickel et une investigation sur les mécanismes mis en jeu. Enfin, une modélisation par éléments finis de l’interaction entre une prothèse articulaire et son environnement osseux est présentée de manière à évaluer la stabilité primaire des implants / As any functional joint, the proximal interphalangeal joint (PIP) is the target of hurts or of pathologies which can compromise the global functions of the hand. The main objectives of a digital arthroplasty are to restore the function and the stability of the joint and to reduce or suppress the pain in a long-lasting way. The present work of thesis concerns the development and the modeling of two concepts of PIP prostheses: a semiconstrained prosthesis made of nickel-titanium alloy and a resurfacing prosthesis. Besides the work of sizing, fatigue and wear tests are done on both implants. Additional studies are presented for each concept. First, we focus on the shaping and the heat treatments of the semi-constrained prosthesis accompanied with a study nickel ion release and an investigation on the involved mechanisms. Eventually, a finite element modeling of the interaction between the prosthesis and the surrounding bone is presented to estimate the primary stability of implants
582

Greffage de polymères biomimétiques sur implants articulaires en polyéthylène : contrôle du comportement tribologique / Grafting biomimetic polymers on polyethylene articular implants : control of the tribological behaviour

Wang, Na 15 April 2013 (has links)
Les maladies ostéoarticulaires représentent environ 10% de l'ensemble des pathologies identifiées en France chaque année. Pour l'instant aucun traitement permettant la réparation du tissu cartilagineux n'est vraiment disponible hormis la pose d'un implant articulaire. Mais, malgré de nombreux efforts pour développer de nouveaux matériaux pour les implants articulaires leur durée de vie in vivo s'avère souvent très décevante par rapport aux extrapolations faites à partir de simulations ex-vivo. Les discordances entre les durées de vie in vivo et ex vivo sont principalement imputées aux conditions d'essais ex vivo insuffisamment réalistes vis-à-vis des propriétés physico-chimiques des lubrifiants biologiques. Dans ce contexte, ce travail vise à agir sur la réactivité physicochimique des surfaces frottantes des implants articulaires en UHMWPE afin de maîtriser l'accrochage des molécules lubrifiantes de type phospholipidique (MPC) et ainsi d'augmenter leurs performances tribologiques. Les résultats montre que l'activation physicochimique des surfaces de UHMWPE par des couches de MPC peuvent diminuer l'usure des surfaces polymères d'implant mais cela nécessite un contrôle de la qualité de la couche MPC greffée (densité surfacique, épaisseur, accrochage chimique, adsorption physico-chimique) afin de garantir une bonne tenue mécanique et tribologique. D'autre part les résultats montrent que la présence de lubrifiant biologique (substitut du fluide synovial à base de liposomes) peut réduire l'usure des surfaces de UHWPE même si la couche de MPC est peu dense et peu épaisse / The osteoarticular diseases account for approximately 10% of all identified pathologies in France each year. Currently there is really no effective treatment available for repairing of the cartilage tissue except for the installation of articular implants. However, in spite of many efforts to develop new materials for articular implants, their lives in-vivo is often disappointing compared with the extrapolations from ex-vivo simulations. The discordances between the lives in-vivo and ex-vivo are mainly contributed to the experimental conditions of ex-vivo insufficiently realistic related to the physic-chemical properties of biological lubricants. In this context, this work aims to investigate physicochemical reactivity of friction surface of UHMWPE articular implants to control the attachment to the lubricating molecules of phospholipid types (MPC) and increase their tribological performance. The results showed that the physicochemical activation of UHMWPE surface with layers of MPC can reduce the surface wear of polymer implant but it requires some quality controls of the grafted MPC layer (surface density, thickness, chemical bonding, physical and chemical adsorption) to ensure good mechanical and tribological performance. In addition, the result also showed that the presence of organic lubricant (substitute synovial fluid containing liposomes) can reduce the surface wear of UHMPE even if the layer is sparse and thin
583

Propriedades mecanicas de resinas acrilicas para base de protese antes e apos metodos de reparos / Mechanical properties of denture base acrylic resins before and after repair methods

Faot, Fernanda 11 October 2006 (has links)
Orientadores: Renata Cunha Matheus Rodrigues Garcia, Altair Antoninha Del Bel Cury / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-07T23:27:29Z (GMT). No. of bitstreams: 1 Faot_Fernanda_D.pdf: 1972781 bytes, checksum: b3ce58297c07d4abe90d5b2bf79729e7 (MD5) Previous issue date: 2006 / Resumo: Fraturas por impacto e flexão ainda são os principais problemas relatados tanto pelos portadores de próteses removíveis como pelos cirurgiões dentistas. Na tentativa de solucionar esse problema, alterações na composição química das resinas acrílicas como a inclusão de co-polímeros, adição de agente de ligação cruzada e a incorporação de partículas de borracha na forma de butadieno estireno têm sido propostas. Entretanto, poucos estudos avaliaram a incorporação destes aditivos modificadores de impacto no processo de fratura, deformação e microestrutura de resinas acrílicas. Além disso, devido à fragilidade dos materiais poliméricos a presença de trincas e fraturas em base de próteses removíveis ainda é alta e reparos são procedimentos comuns tanto por métodos diretos ou indiretos. Entretanto, as propriedades mecânicas de resinas acrílicas reparadas ainda não estão claramente descritas. Assim, os objetivos do presente trabalho foram: I) avaliar a resistência ao impacto e a flexão, bem como tensão de ruptura, módulo Young e deslocamento de escoamento de resinas acrílicas contendo modificadores de impacto e analisar sua microestrutura; II) determinar a resistência ao impacto e flexão de resinas acrílicas para base de prótese previamente fraturadas e reparadas com resinas fotopolimerizável, autopolimerizável e termopolimerizável. Como resultado, observou-se que a resina contendo borracha considerada de alto impacto, demonstrou alta capacidade de dissipação de energia, absorção de tensão e baixo percentual de deformação; entretanto exibiu processo de fratura frágil. Com relação às resinas utilizadas para reparo, concluiu-se que reparos realizados com a mesma resina usada para confecção dos corpos-de-prova, apresentaram melhores resultados quanto à resistência mecânica / Abstract: Fractures by impact and flexural action are the main problems described by denture users and dentists. Attempting to solve this problem, modifications on the chemical composition of the acrylic resins as co-polymer inclusion, cross linking agents addition and rubber particles incorporation in the form of butadiene styrene have been described as effective and worthwhile means to improve the impact strength and fracture propagation. However, literature lacks information regarding the incorporation of these modifying impact additives in the fracture process, plastic deformation and microstructure of acrylic resins. Furthermore, due to the brittleness of the polymeric materials, the presence of cracks and fractures in the removable prosthesis denture bases still remains high. Thus, frequent repairs are somewhat common procedures in the clinical practice, being by direct or indirect methods. Therefore, the effect of the repairs materials on the mechanical properties of acrylic resins is not clearly described yet. Front of these considerations, the purposes of the present study were: I) evaluate the impact and flexural strength, as well as, stress at yield, Young modulus and displacement at yield of acrylic resins containing impact modifiers and analyze their microstructure; II) determine the impact and flexural strength of denture base acrylic resins previously fractured and repaired with visible-light, auto and heat-polymerized acrylic resins. As results, it could be observed that the acrylic resin containing rubber particles, considered as the high impact, showed high capacity of energy dissipation and stress absorption before the fracture, lower percentage of deformation, however it exhibited brittle fracture process. Regarding to acrylic resins used as repair materials, it was concluded that repairs performed with the same resin used to fabricate the specimens showed the best results for mechanical resistance / Doutorado / Protese Dental / Doutor em Clínica Odontológica
584

Necessidade protética da população quilombola de Santo Antônio do Guaporé - Rondônia - Brasil

Maria Eliza de Aguiar e Silva 18 July 2008 (has links)
As populações remanescentes de quilombos tiveram seu direito à propriedade das terras que ocupam garantido pelo Art. 68 dos Atos das Disposições Transitórias da Constituição Federal de 1988. Entretanto, essas populações ainda enfrentam dificuldades de acesso a serviços essenciais como os de saúde. A proposta deste trabalho é apresentar dados referentes ao acesso a serviços odontológicos e estimar a necessidade de prótese da população quilombola de Santo Antônio do Guaporé, Rondônia, Brasil. Para isso, foi realizado um estudo transversal seguindo a metodologia proposta pelo Projeto SB Brasil 2003 para identificar as condições de acesso e a necessidade de prótese dessa população. Foram examinadas 29 pessoas acima de 12 anos de idade. Das 62,1% dessas pessoas que consultaram o dentista pelo menos uma vez; 37,9% consultaram havia mais de três anos; 41,4% foram atendidos no serviço público; para 58,6% dos examinados, o motivo da consulta foi a dor e 44,8% avaliaram o atendimento como bom. Em relação à necessidade de prótese, 48,3% necessitam de prótese superior e 72,4% inferior; 17,2% necessitam de combinação de próteses superior, e 13,8% inferior. Os dados apontam a dificuldade das condições de acesso ao serviço odontológico, e a precariedade das condições bucais, marcadas pela necessidade de tratamento reabilitador. / The leftover populations of hiding-places had a right to the property of the lands that they occupy guaranteed by Art. 68 of the Acts of the Transitory Arrangements of the Federal Constitution of 1988. Meantime, these populations still face difficulties of access to essential services like those of health. The proposal of this work is to present data referring to the access to odontologic services and appreciates the necessity of prosthesis of the population fugitive Negro slave of Saint Antônio of the Guaporé, Rondônia, Brazil. For that, a cross study was carried out when Brazil 2003 is following the methodology proposed by the Project SB to identify the conditions of access and the necessity of prosthesis of this population. 29 persons were examined above 12 years of age. Of 62,1 % of these persons who consulted the dentist at least once; 37,9 % consulted that there were more than three years; 41,4 % was attended in the Civil Service; for 58,6 % of the examined ones, the cause of the consultation went to pain and 44,8 % they valued the service like good. And relation to the necessity of prosthesis, 48,3 % needs superior prosthesis inferior and 72,4 %; 17,2 % needs combination of próteses inferior superior, and 13,8 %. The data point to the difficulty of the conditions of access to the odontologic service, and the precariedade of the buccal conditions, marked by the necessity of treatment reabilitador.
585

Aktivní protéza ruky / Active prostetic hand

Brenner, Maximilian January 2019 (has links)
BACKGROUND: Based on mainly vascular diseases and traumatic injuries, around 40,000 upper limb amputations are performed annually worldwide. The affected persons are strongly impaired in their physical abilities by such an intervention. Through myoelectric prostheses, affected persons are able to recover some of their abilities. METHODS: In order to control such prostheses, a system is to be developed by which electromyographic (EMG) measurements on the upper extremities can be carried out. The data obtained in this way should then be processed to recognize different gestures. These EMG measurements are to be performed by means of a suitable microcontroller and afterwards processed and classified by adequate software. Finally, a model or prototype of a hand is to be created, which is controlled by means of the acquired data. RESULTS: The signals from the upper extremities were picked up by four MyoWare sensors and transmitted to a computer via an Arduino Uno microcontroller. The Signals were processed in quantized time windows using Matlab. By means of a neural network, the gestures were recognized and displayed both graphically and by a prosthesis. The achieved recognition rate was up to 87% across all gestures. CONCLUSION: With an increasing number of gestures to be detected, the functionality of a neural network exceeds that of any fuzzy logic concerning classification accuracy. The recognition rates fluctuated between the individual gestures. This indicates that further fine tuning is needed to better train the classification software. However, it demonstrated that relatively cheap hardware can be used to create a control system for upper extremity prostheses.
586

Řízení aktivní protézy horní končetiny / Active upper limb prosthesis

Brázdil, Štěpán January 2020 (has links)
This thesis focuses on the field of prosthetics, especially the issue of active prosthesis control. The goal is to perform a comprehensive analysis, design and construction of a prosthetic system that, based on the analysis of sensory data (such as an EMG signal from multiple channels), can correctly classify a gesture and a subsequent moving of the limb model. The first parts of the thesis are an important description of the critical components and important parameters of the active prosthesis system, including comparison and selection of available open source solutions. Next is a proposal of interconnection and description of individual hardware and software components. It also includes documentation of the real constructed system, which consists of the InMoov robotic hand, the Raspberry Pi controller and accessories. The results are critically evaluated in the last part of this work.
587

Myoelektrická protéza ruky / Myoelectric prosthetic device of human arm

Lutz, Jan January 2012 (has links)
This project treats of using electromyograph as a control standard for prosthetic replacement of human arm. The work is mainly focused on surface signals. Reader is briefed by creation and transmission of the signal. The work takes account of the transmission of the signal for surface electrodes and the differences between the ideal and the real connection. Another point of the thesis is the design of basic system model for simulation of the robotic arm movement, which depends on the measured signal. In the practical part there is the realization of the artificial limb movement. It starts with the roboric arm construction and continues with the communication between computer and the robotic arm. First part of practical testing ends with creating of an user interface, which is capable of control all robotic arm movements. The interface is combined with a computer model in Matlab robotic toolbox. The model is able to move in sync with the real robot. The final part is devoted to practical measurement with Biopac instruments. The obtained signal is modified to be used as controller for the robotic arm. Author's aim is to adjust this movement to be most similar to real movement.
588

Řízení myoelektrické protézy / Controlling of myoelectric prothesis

Tomanová, Markéta January 2014 (has links)
The Master´s thesis summarizes the knowledge about controlling of myoelectric prostheses. The Introduction part of this work provides an overview of the anatomy of muscles and their contraction. In case of restricted function of hand, it is necessary to compensate this deficiency by using prosthetic limbs. Among one of the most technically difficult is robotic prosthesis. In this semestral work is myoelectric prosthesis replaced by a robotic arm. Arm is controlled by the electromyographic signals. The signals are recorded by Biopac acquision unit, then processed in LabVIEW and robotic system is controlled by the Arduino platform.
589

Experimentální biomechanická protéza ruky / Experimental biomechanical hand prosthesis

Lux, Martin January 2012 (has links)
This masters thesis deals with experimental biomechanical hand prosthesis designing and its realization in shape of prototype. Hand prosthesis sizing corresponds with adult man hand. Prosthesis functionality is selected with respect to search analysis results, to provide sufficient options to grip different objects. Hand design, including technical documentation, is completely made in Autodesk Inventor 2012. Main parts of prototype are made with using rapid - prototyping technologies. Used materials for parts made by this way are ABS plastics and plaster powder. Firgelli linear actuators (product line L) are used as drive for electrical controlled fingers. Prototype control is realized by PCI card and program, which has been written in LabView.
590

Konstrukce transtibiální protézy s využitím aditivní technologie výroby. / Design of Transtibial Posthesis With Use of Additive Manufacturing Technology.

Kopecký, Martin January 2013 (has links)
The thesis deals with the design of a transtibial prosthesis by additive manufacturing technology. Based on walking biomechanics and the current situation of knowledge a prosthetic foot has been designed for a patient with low level of physical activity. Furthermore, the thesis describes the design of an individual socket for the patient. The socket has been designed by reverse engineer procedure based on the three-dimensional geometry of patient´s stump obtained by 3D scanning. Testing samples of the foot and the socket have been made for the check of functionality of both the devices and then subjected to mechanical tests in accordance to the methodology regulation ISO 10328. Finally, the thesis depicts the FDM technology used for the production of functional samples of the designed devices; assembly of modular transtibial prosthesis and its testing by the patient.

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