No description available.

No description available.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 102-105). Also available via the Internet.

Thesis (MTech (Technology : Mechanical Engineering))--Cape Peninsula University of Technology, 2006 / Recent years have witnessed a tremendous growth and significant advances in "smart" composites and "smart" composite structures. These smart composites integrate active elements such as sensors and actuators into a host structure to create improved or new functionalities through a clever choice of the active elements and/or a proper design of the structure. Such composites are able to sense a change in the environment and make a useful response by using an external feedback control system. Depending on their applications. smart composites usually make use of either the joint properties of the structure or the properties of the individual elements within the composites. The accumulation in the understanding of materials science and the rapid developments in computational capabilities have provided an even wider framework for the implementation of multi-functionality in composites and make "smart" composites "intelligent". This thesis is a contribution towards the global endeavour to innovate using smart structures to enhance our everyday lives. One of the phenomena of shape memory alloys. the shape memory effect was put to use in the development of an active surface. Here the pre-stressed shape memory alloy (in its de-twinned martensitic state) is surrounded or embedded in a non-SMA matrix material. This active surface can be used in a variety of applications that requires active shape control to change the shape of a flexible structure member such as a submarine stem, aerospace control surfaces and aircraft wings. An experimental protocol was developed to treat or stabilize shape memory alloys that are used as actuators within composite structures. Shape memory alloys exhibit complex behaviour during their quasi-plastic material response. The complex behaviour includes variability in yield values and the transformation region/range.

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2005 / The working characteristics of a shape memory alloy element providing either sensor or actuator capability is specified by the beginning and/or completion temperatures of the actuation (Le. austenitic start and finish temperatures and martensitic start and finish temperatures), the working actuator stroke (i.e. load induced twinned=:>de-twinned martensitic phase transformation also known as quasi-plastic deformation), and the working actuator force (provided by the temperature induced de-twinned martensite

No description available.

Thesis (M. Sc.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Jan. 8, 2010). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science, Department of Mechanical Engineering, University of Alberta." Includes bibliographical references.

Laser-based techniques have become essential tools for probing biological molecules in systems that demand high spatial and temporal control. This dissertation presents the development of micro-analytical techniques based on multiphoton excitation (MPE) to promote highly localized, three-dimensional (3D) photochemistry of biologically relevant molecules on submicron dimensions. Strategies based on capillary electrophoresis (CE) have been developed for the rapid separation and spectroscopic analysis of short-lived photochemical reaction products. High-speed separation and analysis are achieved through a combination of very high electric fields and a laser-based optical system that uses MPE for both the generation and detection of hydroxyindole photoproducts on the time scale of microseconds. MPE was also used for the development of photolithographic techniques for the creation of microstructured protein-based materials with highly defined three-dimensional (3D) topographies. Specifically, a multiphoton lithographic (MPL) technique was developed that used a low-cost microchip laser for the rapid prototyping of 3D microarchitectures when combined with dynamic optical masking. Furthermore, MPL was used to create novel “smart” biomaterials that reproducibly respond with tunable actuation to changes in the local chemical and thermal environment. The utility of these materials for creating biocompatible cellular microenvironments was demonstrated and presents a novel approach for studying small populations of microorganisms. Finally, through the development of a multifocal approach that used multiple laser beams to promote the photocrosslinking of biological molecules, the speed and versatility of MPL was extended to allow both the parallel fabrication of 3D microstructures and the rapid creation of large-scale biomaterials with highly defined spatial features. / text

Ionic polymer metal composite (IPMC) is used in various bio-inspired systems, such as fish and tadpole-like robots swimming in water. The deflection of this smart material results from several internal and external factors, such as water distribution and surface conductivity. IPMC strips with a variety of water concentration on the surfaces and surface conductivity show various deflection patterns. Even without any external excitation, the strips can bend due to non-uniform water distribution. On the other hand, in order to understand the effects of surface conductivity in an aquatic environment, an IPMC strip with two wires connected to two distinct spots was used to demonstrate the power loss due to the surface resistance. Three types of input signals, sawtooth, sinusoidal, and square waves, were used to compare the difference between the input and output signals measured at the two spots. Thick (1-mm) IPMC strips were fabricated and employed in this research to sustain and drive the robot with sufficient forces. Furthermore, in order to predict and control the deflection, researchers developed the appropriate mathematical models. The special working principle, related to internal mobile cations with water molecules, however, makes the system complicated to be modeled and simulated. An IPMC strip can be modeled as a cantilever beam with loading distribution on the surface. Nevertheless, the loading distribution is non-uniform due to the non-perfect surface metallic plating, and four different kinds of imaginary loading distribution are employed in this model. On the other hand, a reverse-predicted method is used to find out the transfer function of the IPMC system according to the measured deflection and the corresponding input voltage. Several system-identification structures, such as autoregressive moving average with exogenous (ARX/ARMAX), output-error (OE), Box-Jenkins (BJ), and prediction-error minimization (PEM) models, are used to model the system with their specific mathematic principles. Finally, a novel linear time-variant (LTV) concept and method is introduced and applied to simulate an IPMC system. This kind of model is different from the previous linear time-invariant (LTI) models because the IPMC internal environment may be unsteady, such as free cations with water molecules. This phenomenon causes the variation of each internal part. In addition, the relationship between the thickness of IPMC strips and the deflection can be obtained by this concept. Finally, based on the experimental results above, an aquatic walking robot (102 mm × 80 mm × 43 mm, 39 g) with six 2-degree-of-freedom (2-DOF) legs has been designed and implemented. It walked in water at the speed of 0.5 mm/s. The average power consumption is 8 W per leg. Each leg has a thigh and a shank to generate 2-DOF motions. Each set of three legs walked together as a tripod to maintain the stability in operation.

Thesis (Ph. D.)--School of Aerospace, Mechanical and Mechatronic Engineering, Graduate School of Engineering, University of Sydney, 2005. / Bibliography: leaves R1-R20.