Crack-healing of structural ceramics is a most valuable technique to overcome their weak point such as surface cracks. Crack-healing ability appeared by admixing SiC to ceramics, because this function is to use the oxidation of SiC. Endowment of crack-healing ability as well as improvement in fracture toughness was expected to be achieved by compositing SiC whiskers. For this purpose, alumina / 30 vol% SiC whiskers and alumina/ 20vol% SiC whiskers/ 10 vol% SiC particles multi-composites were developed. Crack-healing ability and fracture toughness of these composites were investigated. Alumina/ 20 vol% SiC whiskers/ 10 vol% SiC particles multi-composite and alumina/ 30vol% SiC whiskers composite were found to have 1.43 times and 1.65 times higher fracture toughness than monolithic alumina, respectively. From the results of the strength recovery by crack-healing, alumina/ 20 vol% SiC whiskers/ 10 vol% SiC particles multi-composite and alumina / 30vol% SiC whiskers composite were found to be able to heal the pre-crack below 0.250 μm and 0.200 μm in surface length, respectively. In spite of the same SiC content, SiC particles and SiC whiskers multi-compositing enlarged the limit crack size to be able to crack-heal. On the other hand, increasing SiC whiskers content enhanced strength recovery of the specimen with the large crack above limit crack-size.

Conventional Ge2Sb2Te5 (GST) was modified by adding up a small amount of SiOx, using co-sputtering technique from multiple targets. The SiOx content was gradually increased by increasing the power applied to SiOx target, up to 8 volume percent. The sheet resistance of SiOx-containing GST exponentially increased, when the room-temperature-deposited samples were annealed at 300 °C. Transmission electron microscopy images revealed that no SiOx particulates were formed, which was confirmed by Gattan image filtering. It was indicated by x-ray diffraction patterns that the grain size of SiOx-containing GST is smaller than normal GST with lattice locally distorted at its crystalline state, suggesting that molecular SiOx is homogeneously distributed throughout the GST matrix. We observed that the crystallization temperature of SiOx-containing GST is gradually elevated by increasing the SiOx content, while the melting point decreased. These observations led to the reset current reduction, which is a critical requirement for the high density PRAM.

Novel cross-linkable, highly fluorinated poly(arylene ether ketone/sulfone)s have been prepared by copolycondensation reactions of a perfluorinated aromatic ketone or sulfone with 4,4'-(hexafluoroisopropylidene)diphenol (6F-BPA)/4,4'-isopropylidene bis(2,6-dibromophenol) (4Br-BPA) and a tetrafluorostyrol-containing bisphenol, at low temperature in the presence of calcium hydride and cesium fluoride. Property investigations have shown that these polymers can be easily processed into thin films, have good thermal stability, and exhibit low optical loss at 1550 nm (0.4 – 0.5 dB/cm). The refractive index can be tailored over a range of 1.50 to 1.57, allowing the polymers to be used as both core and cladding materials in optical waveguiding applications.

We study the magnetostrictive behavior of two types of films: one is released from the substrate but constrained from its lateral boundary and the other is attached to the substrate. The former is investigated using the recently developed micromagnetic model which is suitable for films subjected to realistic magneto-mechanical boundary conditions. The latter is modeled within a framework extended from our recent theoretical paper studying rough alloy films with composition modulation. We give an explicit form of the stress-induced magnetic field taking into account the elastic interaction of the film with the substrate. Such results are very different from those considered for attached thick films in literature.

Ink jet technology is applied to the industry application of CPU cooling in this study. The PZT actuated micro-cooling device which generating the micro-scale liquid droplet is used in the CPU cooling of desktop and laptop PCs. It consists the advantages of long lifetime of operation, simple and easily manufactured of the structure with PZT actuator. Since the high latent heat transfer rate, 2260 J/g, of water droplet for the liquid-vapor phase change cooling system, it removes heat from the CPU surface effectively for over 100 W. In order to design an efficient cooling device, it is important to study the PZT material property varies after the laser cutting process and the dimensional effects of PZT actuator on the nozzle plate vibration mode. The frequency and amplitude of the voltage used to energize the PZT transducer are also important parameters that should be properly controlled in order to achieve the optimal liquid breakup conditions. It also reveals the low noise and power consumption in the CPU cooling system with some appropriate operational conditions.

We present the synthesis and optical and electrical characterization of amorphous nanocomposite layers made of metallic nanoclusters embedded in an alumina (Al2O3) matrix (nc-M:Al2O3 with M= Ag, Cu and Co). The nanocomposites, obtained by a pulsed laser deposition (PLD)- derived method, exhibit specific optical plasma resonance absorption in the visible and UV region. The position of the absorption peaks depends on the cluster type and gives information about its dimension and nature (metal or oxide). The results fit well with the size and shape distribution recorded by transmission electron microscopy (TEM). Electrical properties and conduction mechanisms of nc-Co:Al2O3 layers were investigated for different doping levels and in temperature range of 303-473 K. It was concluded that space charge limited currents theory (SCLC) can be assumed as major conduction mechanism, at least for intermediate doping levels (∼9 vol.%).

This work characterizes magnetostrictive single crystal Fe84Ga16 (Galfenol) as static and dynamic sensor in bending mode. Galfenol patch bonded to a cantilevered aluminum beam was characterized for static and dynamic loading of the beam. A figure of merit has been defined and sensor parameters have been obtained for different stress conditions and Galfenol patch thickness. Issues related to application in static and dynamic sensing have been discussed.

An energy-based constitutive model that can simulate the performance of magnetostrictive actuators and sensors along any of the crystallographic orientations was developed. This model was validated by comparing its predictions with experimental actuator characteristics (λ-H and B-H curves) along the <100> and <110> directions as well as sensor characteristics (B-σ curves) along the <100> direction of single crystal FeGa samples with ∼18-19 at. % Ga. These experimental characteristics were obtained using 6.35 mm (1/4 inch) diameter and 25.4 mm (1 inch) long, oriented single crystal rods grown using the Bridgman method by the DOE Ames Lab.

Ageing is a general problem also applicable in engineering. Many of our engineering struc-tures are seemingly built ageless. Others were built with higher safety factors to cope with the lack of engineering knowledge at the time, where enhanced knowledge nowadays allows these structures to be used longer than initially anticipated. Consequently new design principles may allow future structures to be further built lighter weight. Much of this enhancement can result from the implementation of smart systems technologies into design. This paper will give a few examples based on integrated sensing as well as actuation principles into structures.

Resistive type sensors using 10 mol% Hf-doped ceria and 10 mol% Zr-doped ceria, which had a single cubic phase obtained by solid state reaction, were fabricated and their sensing properties were investigated. The resistance and resistivity of the 10 mol% Hf-doped ceria or 10 mol% Zr-doped ceria were smaller than those of non-doped ceria. In the case of the same temperature of solid state reaction, the resistance and resistivity of the 10 mol% Hf-doped ceria were much smaller than those of the 10 mol% Zr-doped ceria. Furthermore, in the case of the same dopant, the resistance and resistivity of the sensor prepared from the solid state reaction at 1773 K were much smaller than those at 1673 K. The sensor using the 10 mol% Hf-doped ceria could be used as an oxygen gas sensor in wide oxygen partial pressure range and could be applicable to a λ sensor and a universal A/F sensor.

This paper reports the development and characterization of PZT nanofibers with average diameters ranged from 50 to 150 nm for various sensing and actuation applications. PZT nano fibers have been developed by sol-gel electrospinning process. Both randomly distributed and uniaxially aligned PZT fibers were obtained from the sol-gel solution with viscosity modified by polyvinyl pyrrolidone (PVP). The diameters of the nano fibers can be further reduced or controlled for different applications. The morphology and structure of the nanofibers were examined with SEM, TEM and XRD. We used two-step process to anneal the electrospun fibers and XRD confirmed that pure perovskite phase was formed after the as-spun fibers being annealed at about 650°C. TEM results showed that the grain size of the fibers was about 10 nm. Microelectromechanical (MEMS) based micro-fabrication technologies were used to assist the development of the nano-fibers in designing the test samples, depositing and patterning the electrodes, and also testing the performance of the nano fibers. Different approaches have been explored to fabricate the uniaxially aligned nano fibers. SEM results showed that partial aligned PZT nano-fibers were obtained on the pre-patterned substrats. Interdigitated Electrodes were evaporated on the partial aligned fibers by using shadow mask. Hysteresis curve of the nano piezoelectric fibers was also obtained, however further tests are still needed to get accurate measurement. The obtained PZT nanofibers have promising application potentials in designing and enabling micro and nano devices.