The amorphous to crystalline phase change is of great interest for the production and operation of phase change memory and germanium electronic devices. Phase change memory relies on the ability to differentiate between differences in optical or electrical properties between the amorphous and crystalline phases of a single material. Amorphous...
The thermal degradation of structural materials is considered to be a key factor for evaluating the lifetime of current nuclear power plants. Ni-based and Fe-based alloys, such as 690, 625, 304, and 316, are widely used in nuclear industry as structural components due to the extraordinary corrosion resistance and mechanical...
This thesis outlines the development of new elastomeric materials and manufacturing processes for soft robotics. Specifically, this work describes the development of custom material formulations for use in additive manufacturing, additive manufacturing processing techniques for silicone elastomers, and multi-component additive manufacturing techniques. Material synthesis and processing is a gap in...
Heating, ventilation, and air conditioning systems represent nearly half of building energy usage in the United States. Recent building regulations requiring increased air turnover within buildings will result in even greater air conditioning usage. To alleviate these concerns, membrane-based heat-and-moisture exchangers known as energy recovery ventilators have been developed to...
Fe25Co25Ni25Cr25-XMoX High Entropy Alloys were fabricated in mini arc-melter and then cast into 4mm diameter cylinders by injection casting technique and 1cm diameter cylinders by water quenching technique. Heat transfer modeling during solidification of FeCoNiCr HEA was simulated. Combining X-Ray Diffraction, Optical Microscopy, Scanning Electron Microscope, Energy Dispersive X-ray analysis,...
Sodium-ion batteries (SIBs) require the use of a highly reversible anode. To form this anode carbon nanofibers and nanocrystals are derived from cellulose nanofibers, cellulose nanocrystals, and bacterial nanocellulose. The primary structure of the cellulose nanofibers is maintained when carbonized allowing for high surface area in the structure. The carbon...
The advent of supercritical CO2 as a new heat-exchange medium has seen strong interest from the power industry and the energy research field recently. It is advan- tageous in comparison with other heat-exchange cycles, as it can be operated safely at much higher temperatures and pressures, thus increasing the thermal...
This work explores the electric field induced strain mechanisms in environmentally benign Bi0.5Na0.5TiO3 (BNT) based piezoelectric thin films. Although BNT-based materials show promise as replacements for toxic Pb-based piezoelectrics, the displacement mechanisms are not consistent between thin films and bulk materials, and the differences have yet to be well understood....
Wood composites are an important renewable structural material which can be a net carbon sink when used in combination with sustainable forest management practices and high rates of log utilization. Adhesive bondlines are an essential part of composites, and for wood composites, they determine the moisture durability and mechanical performance...
Phase change memory materials are a set of chalcogenide or pnictogenide materials systems currently being researched for use in optical and resistive based memory systems due to their large change in optoelectronic properties between the amorphous and the crystalline states. For these materials systems to be considered as a suitable...
New low enriched uranium (LEU) fuels are being developed for replacement of high enriched uranium (HEU) fuels in high power research reactors. U-Mo LEU plate fuels have been identified as a candidate for replacement of current HEU fuels. However, U-Mo fuels tend to exhibit accelerated swelling typically at fission densities...
The corrosion resistances of several alloys were investigated to optimize performance and cost in seawater and supercritical CO2 environments. Many alloys are prone to corrosion in seawater and/or supercritical CO2 containing impurity environments. Exposure and electrochemical experiments were conducted in both environments to evaluate alloys’ corrosion resistance. In seawater corrosion...
Time-dependent crack growth mechanisms in Alloy 617 at 800°C in air were studied using compact tension samples machined in the L-T direction, cracked at temperature using an induction furnace and servo-hydraulic load frame. The application of different loading waveforms, including triangular, hold time, and sustained loading, were studied with relation...
The ternary system (Bi₀.₅Na₀.₅)TiO₃-(Bi₀.₅K₀.₅)TiO₃-Bi(Mg₀.₅Ti₀.₅)O₃ (BNT-BKT-BMgT) was explored along the [75-(x 2) ]Bi₀.₅Na₀.₅TiO₃ - [25-(x 2)]Bi₀.₅K₀.₅TiO₃ - [x]Bi(Mg₀.₅Ti₀.₅)O₃ composition line. Thin films were fabricated using chelated mixing route solutions spin cast onto platinized silicon substrates. Processing parameters such as: excess cation molar%, solution molality, and crystallization temperatures, for composition where x=0,...
In Intense Pulsed Light (IPL) sintering, pulsed large-area visible light from a xenon lamp is absorbed by nanoparticle films or patterns and converted to heat, resulting in rapid sintering of the nanoparticles. This work experimentally characterizes IPL sintering of silver nanoparticle films. A newly observed turning point in the evolution...
Atomically-thin graphene sheets have unprecedented characteristics for biosensing applications. These characteristics include mechanical flexibility and strength, optical transparency, electrical sensitivity and biocompatibility. The primary theme of this dissertation is the characterization and application of graphene field-effect transistors (FETs) in biologically-relevant physiological environments.Understanding the interface that forms between an electrolyte and...
Oxo-hydroxo Group 5 metal clusters are an untapped resource to study and advance aqueous solution processing of metal oxide thin films. The tetramethylammonium (TMA) hexatantalate salt (TMA6[H2Ta6O19]) yields dense Ta2O5 films (~95% of the bulk ß-Ta2O5 density) with atomically smooth surfaces (<4 Å root mean square surface roughness). This same...
CIGS and CdTe based commercial thin-film solar cells (TFSCs) require an absorber thickness greater than 2 µm and 4 µm, respectively, to adequately absorb the solar spectrum. To efficiently extract photoexcited electrons, these TFSCs require relatively defect-free absorbers with high-minority carrier mobility (> 100 cm2V−1s−1) and long lifetime (> 10...
Cross-laminated timber (CLT) is a massive engineered wood product made of orthogonally bonded layers of solid-sawn lumber, and is intended for roof, floor, or wall applications. Although it was developed in Europe in the early 90s, CLT is relatively new to North America.
CLT products must be certified for structural...
The metal-organic–framework MOF-5 is used as an adsorbent in advanced systems for vehicular hydrogen storage that are currently under development. Presently, these systems are limited by poor thermal conductivity of the adsorption bed, and thus our research addresses how the interfaces between grains of MOF-5 can be engineered to improve...