Thesis (MS)--Montana State University--Bozeman, 2010. / Typescript. Chairperson, Graduate Committee: David A. Miller. Includes bibliographical references (leaves 69-73).

Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2006. / Arkin, Ronald, Committee Member ; DeWeerth, Steve, Committee Member ; Vito, Raymond, Committee Member ; Ebert-Uphoff, Imme, Committee Member ; Book, Wayne, Committee Chair. Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 71-79). Also available on the World Wide Web.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 175-180).

Thesis (Ph. D.)--University of Nevada, Reno, 2006. / "December, 2006." Includes bibliographical references (leaves 167-180). Online version available on the World Wide Web.

Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 26, 2007) Includes bibliographical references.

Le Poly(vinylidene-fluoride) (PVDF) est un polymère piézoelectrique pouvant être utilisé comme capteur, actuateur ou pour de la récupération d'énergie. Son copolymère dérivé le poly(vinylidene-fluoride–trifluoroethylene) (P(VDF-TrFE)) possède des propriétés similaires tout en étant plus simple à préparer que le PVDF. Il est compatible avec une technologie tout imprimée pour fabriquer des dispositifs transparents sur des substrats flexibles. Le premier objectif de cette thèse est d'analyser l’intérêt des couches minces de P(VDF-TrFE) imprimées pour l'actuation et de comparer avec la dernière génération de polymères dérivés: le Poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)). Après une étude des différentes compositions l'objectif est d'améliorer la compréhension des mécanismes de déformations pour ouvrir la voie à de nouvelles améliorations. Les travaux menés sont présentés ici en trois parties distinctes. La première est consacrée à l’étude des propriétés mécaniques et électriques des polymères. L'influence du taux de CTFE est analysée et les polymères séparés en 3 catégories distinctes en fonction de leur nature ferroélectrique. Les performances pour l'actuation de chacune de ces catégories sont étudiées. Deux figures de merites sont retenues : le déplacement (et la force) que peuvent générer l'actuateur et le coefficient de couplage pour comparer le coût en énergie du dispositif. Le choix d'un terpolymère adapté dépend de l'application envisagée et peut permettre une augmentation significative de la réponse mécanique comparé à un copolymère. En revanche le coût énergétique est toujours beaucoup plus important, au minimum le double, quelle que soit l'application .Cette première étude a aussi mis en évidence l'hystérésis et les non-linéarités dans la relation champ électrique-déformation des polymères. La deuxième partie reprend les relations constitutives de la piézoélectricité pour analyser plus avant les divergences entre la théorie et l'expérience. Ces divergences servent de points de départ à des hypothèses et modèles de déformation dans le copolymères et dans les terpolymères. De nombreuses observations indirectes montrent l'existence d'une transition de phase sous l'effet du champ électrique; en se basant sur les données de déformation et de polarisation, l'analyse présentée ici identifie une plage limitée de champ pour cette transition et quantifie son poids dans la déformation totale du matériau.La troisème partie est consacrée à la mise en évidence expérimentale des hypothèses de la partie précédente. La principale étude est l'observation in-situ de la transition de phase sous l'effet du champ par diffraction aux rayons X. Cette mise en évidence expérimentale confirme une partie des explications avancées et une étude en température permet d'aller plus loin en jouant sur la dépendance des phases à la température.Ces travaux apportent une analyse de la viabilité des différents polymères pour l'actuation. L'étude de la relation champ électrique-déformation apporte des outils pour la modélisation et une meilleure compréhension des mécanismes à l’œuvre dans ces matériaux. Les observations in-situ de la microstructure permettent de valider physiquement les modèles présentés. Ils apportent une meilleure compréhension de la physique même si de nombreuses zones d'ombre subsistent, notamment au niveau de la phase amorphe. / Poly (vinylidene-fluoride) (PVDF) is a piezoelectric polymer that can be used as a sensor, actuator or for energy harvesting. Its copolymer derivative poly (vinylidene-fluoride-trifluoroethylene) (P (VDF-TrFE)) has similar properties whilst being easier to process than PVDF. It is compatible with fully printed technologies to make transparent devices on flexible substrates. The first objective of this thesis is to analyze the interest of print thin films of P (VDF-TrFE) for the actuation and to compare with the last generation of derived polymers: Poly (vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) ( P (VDF-TrFE-CTFE)) terpolymers. After a study on the different compositions the objective is to improve the understanding of the deformation mechanisms to pave the way for new improvements. The work is presented here in three separate parts. The first is devoted to the study of the mechanical and electrical properties of polymers. The influence of the CTFE content is analyzed and the polymers separated into 3 distinct categories based on their ferroelectric nature. The performances for the actuation of each of these categories are studied. Two figures of merits are retained: the displacement (and the force) that can be generated by the actuator and the coupling coefficient to compare the energy cost of the device. The choice of a suitable terpolymer depends on the intended application and may allow a significant increase in the mechanical response compared to a copolymer. On the other hand the energy cost with a terpolymer is always much more important, at least twice that of a copolymer.This first study revealed hysteresis and nonlinearities in the electric field-strain relationship of polymers. The second part takes up the constituent relations of piezoelectricity to analyze further the divergences between the theory and the experiment. These divergences serve as starting points to understand and model the deformation in co- and ter-polymers. Many indirect observations show the existence of a phase transition under the effect of the electric field; based on deformation and polarization data, the analysis presented here identifies a limited field range for this transition and quantifies its weight in the total deformation of the material.The third part is devoted to the experimental demonstration of the hypotheses made in the modelling section. The main study is the XRD in-situ observation of the phase transition under the effect of an electrical field. This experimental evidence confirms some of the proposed explanation and a temperature study allows us to go further, making use of the dependence of phases stability to the temperature.This work provides an analysis of the viability of the various polymers for the actuation. The study of the electric field-strain relationship provides tools for modeling and a better understanding of the mechanisms at work in these materials. In-situ observations of the microstructure make it possible to physically validate the models presented. They bring a better understanding of physics even if many uncertainties remain, especially in the amorphous phase.

Thesis (DTech (Mechanical Engineering))--Peninsula Technikon, 2004. / Engineers and Technologists have always been identified as those individuals that put into practice the theories developed by scientists and physicists to enhance the lives of human beings. In the same spirit as those that came before, this thesis describes the development of a computational engineering tool that will aid Engineers and Technologists to design smart or intelligent structures comprising of NiTi shape memory alloy rods for actuation purposes. The design of smart actuators consisting of NiTi shape memory alloy structural members will be beneficial to industries where light weight, compactness, reliability and failure tolerance is of utmost importance. This is mainly due to the unique material responses exhibited by this smart material. The shape memory effect, one of these material responses consists out of two stages: a low temperature load induced phase transformation causing a macroscopic deformation (either extension, contraction, etc.) also known as quasi-plasticity; and a high temperature phase transformation that erases the low temperature macroscopic deformation and reverts the material to some predefined geometry. When designing actuators consisting of this smart material, the quasi-plastic material response produces the actuation stroke while the high temperature phase transformation produces the actuation force. The successful engineering design of smart structures and devices particularly suited for applications where they operate in a capacity, as actuators harnessing the shape memory effect are dependent on a few important factors. These include the engineers familiarity with the type of smart material used, the availability of sound experimental data pertaining to the complex material responses exhibited by the smart material, the engineers level of proficiency with existing constitutive models available to simulates these material responses, and the engineers knowledge of simulation tools consisting of a suitable control algorithm fo~ the modeling of not only the device or structure itself but also the actuator involved in the design.

University of Macau / Faculty of Science and Technology / Department of Electromechanical Engineering

Conventional healthcare and the practice of medicine largely relies on the ineffective concept of one size fits all. Personalized medicine is an emerging therapeutic approach that aims to develop an advanced therapeutic technique that provides tailor-made therapy based on every individuals’ needs by delivering the right drug at the right time with the right amount of dosage. The advancement in technologies such as flexible electronics, microfluidics, biosensors, and advanced artificial intelligence can enable the realization of a truly effective personalized therapy. However, currently, there is a lack for a personalized minimally-invasive wearable closed-loop drug delivery system that is continuous, automated, conformal to the skin and cost-effective. Thus, this thesis focuses on the design, fabrication, optimization, and application of an automated personalized microfluidics drug delivery platform augmented with flexible biosensors, heaters, and expandable polymeric actuator. The platform provides precise drug delivery with spatiotemporal control over the administered dose as a response to real-time physiological changes of the individual. The system is flexible enough to be conformal to the skin and drug is transdermally administered through biocompatible microneedles. The platform includes a flexible multi-reservoir microfluidics layer, flexible and conformal heating elements, skin sensors and processing units which are powered by a lightweight battery integrated into the platform. The developed platform was fabricated using rapid, cost-effective techniques that are independent of advanced microfabrication facilities to expand its applications to low-resource setting and environments.