NiTiHf alloys have emerged as potential materials for applications requiring high transformation temperatures (> 100 °C) with high strength and work output. Although they have high transformation temperatures, their low damping capacity, brittleness and poor superelastic responses (of Ti-rich NiTiHf) impedes their wider usage in many industrial applications. In this study, the quaternary alloying element of Pd has been added to NiTiHf alloys to improve and tailor their shape memory behavior,. NiTiHfPd alloys were systematically examined regarding the composition and heat treatments effects. Effects of substituting Hf with Ti on the shape memory behavior of NiTHfPd alloys were investigated. There compositions were selected as Ni40.3Ti34Hf20Pd5 Ni40.3Ti39.7Hf15Pd5 and Ni40.3Ti44.7Hf10Pd5 (at.%). Their transformation temperatures, microstructure and shape memory properties were revealed and compared with conventional shape memory alloys. It was revealed that their transformation temperatures increases but transformation strain decreases with the increment of Hf content. Additionally, superelastic responses of Ni45.3Ti29.7Hf20Pd5 andNi45.3Ti39.7Hf10Pd5 alloys were investigated. Transformation temperatures of polycrystalline Ni45.3Ti29.7Hf20Pd5are highly dependent on aging temperatures and they can be altered widely from room temperature to 250 oC. Finally, the damping capacity of the Ni45.3Ti39.7Hf10Pd5 polycrystal and [111]-oriented Ni45.3Ti29.7Hf20Pd5 single crystal were investigated. The damping capacities were found to be 16-25 J.cm-3, and 10-23 J.cm-3 for the Ni45.3Ti39.7Hf10Pd5 and [111]-oriented Ni45.3Ti29.7Hf20Pd5 alloys, respectively.

We present a fabrication process to create bifunctional microparticles displaying two different proteins have been spatially segregated onto hemispheres. Silica and polystyrene microparticles with 2.0 m, 4.08 m, and 4.74 m diameters are processed with metal deposition to form two chemically distinct and segregated hemispheres. The surface of each hemisphere is then separately derivatized with proteins using different chemical conjugation strategies. These bifunctional Janus particles possess biologically relevant, native conformation proteins attached to a biologically-unreactive and safe substrate. They also display high densities of two types of spatially segregated proteins which may enable a range of capabilities that monofunctional particles cannot, such as improved targeting of drug carriers and bioimaging agents.

Dynamic materials which can sense changes in their surroundings and subsequently respond or adapt by autonomously altering their functionality, surface chemistry, transparency, color, wetting behavior, adhesiveness, shape, etc. are primed to be integral components of future "smart" technologies. However, such systems can be quite complex and often require intricate coordination between both chemical and mechanical inputs/outputs as well as the combination of multiple materials working cooperatively to achieve the proper functionality. It is critical to not only understand the fundamental behaviors of existing dynamic chemo-mechanical systems, but also to apply that knowledge and explore new avenues for design of novel materials platforms which could provide a basis for future adaptive technologies. Part 1 explores the use of environmentally-sensitive hydrogels, either alone or within arrays of high-aspect-ratio nano/microstructures, as chemo-mechanical actuators. Chapters 1 through 7 describe a bio-inspired approach to the design of hybrid actuating surfaces in which the volume-changing hydrogel acts as the “muscle” that reversibly actuates the microstructured "bone". In particular, the different actuation mechanisms arising from variations in how the hydrogel is integrated into the structure array, how chemical signals can be used to manipulate actuation parameters, and finally how such a system may be used for applications ranging from adaptive optics to manipulation of chemical reactions are described. Chapter 8 discusses the use of responsive hydrogel scaffolds as a means to mechanically compress cells and direct differentiation. Part II explores dynamic microsystems involving the integration of catalytic sites within intricately structured 3D microenvironments. Specifically, we explore a generalizable and straightforward route to fabricate microscale patterns of nanocrystalline platinum and palladium using multiphoton lithography. The catalytic, electrical, and electrochemical properties are characterized, and we demonstrate high resolution integration of catalysts within 3D-defined microenvironments to generate directed particle and fluid transport. / Chemistry and Chemical Biology

Scientists are constantly seeking new and convenient non-destructive damage assessment techniques. In fact, a global market has developed for structural health monitoring products. Many of the currently available techniques are expensive and difficult to implement. An inexpensive alternative is technology based on strain memory alloys. These materials encompass a vast array of alloys, from austenitic stainless steels through to the extremely high strength TRIP steels. All, however, have in common the transformation from paramagnetic austenite to ferromagnetic martensite upon application of strain. The degree of ferromagnetism can be directly correlated to the peak strain undergone by the material. Strain memory alloys are not as expensive to manufacture as some smart materials, and in addition are capable of bearing significant load, and it is therefore possible to manufacture entire components from these alloys, thereby producing what is known as a smart component, i.e. one that is capable of doing the job of an ordinary component while at the same time assessing its own peak damage levels. A possible application of this technology is that of wing bolts for the Hercules e130 aircraft. The material usually used to manufacture the aircraft wing bolts is HSLA steel (AISI 4340). A strain memory alloy was therefore developed to match the mechanical properties of 4340 steel, while also having the requisite properties to perform the self damage-assessment. Ultra high strength TRIP steels were identified as possible candidates, and four alloys selected for investigation. These alloys were melted and then thermo-mechanically processed using a rolling operation. All alloys were tensile tested and magnetic susceptibility monitored. The final material selected possesses an ultimate tensile strength (UTS) of between 1270 and 1500 MPa with 10 to 12% elongation. The stress / strain induced transformation begins to occur before the yield point, which is important because bolts must be replaced before they fail. Compression tests were also performed, and yielded similar results to those of the tensile tests, with martensitic transformation again beginning before plastic yield. The strain induced phase transformation was confirmed not only by magnetic susceptibility measurements, but also by metallographic inspection before and after testing. A subscale Smart bolt was designed, manufactured and tested for magnetic sensitivity using a smart washer. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2005.

No description available.

Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Mechanical and Aerospace Engineering." Includes bibliographical references (p. 201-206).

Thesis (M.A. Sc.)--University of Toronto, 2006. / Source: Masters Abstracts International, Volume: 44-06, page: 2869. Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 123-127). Also available via the Internet.

Thesis (Ph.D.) - University of St Andrews, September 2007. / Restricted until 14th September 2009.

Thesis (Ph. D.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2007. / Andreas S. Bommarius, Committee Member ; L. Andrew Lyon, Committee Member ; J. Carson Meredith, Committee Member ; William J. Koros, Committee Member ; Victor Breedveld, Committee Chair.