A cementitious waste form known as Cast Stone is the baseline waste form for solidification of aqueous secondary wastes, including Hanford Tank Waste Treatment and Immobilization Plant (WTP) secondary liquid effluents to be treated and solidified at the Hanford Site Effluent Treatment Facility. Cast Stone is also being evaluated as a possible supplemental immobilization technology to provide the necessary low activity waste (LAW) treatment capacity to complete the Hanford tank waste cleanup mission in a timely and cost effective manner. Two radionuclides of particular concern in these waste streams are technetium-99 (99Tc) and iodine-129 (129I). These radioactive tank waste components are predicted to contribute the most risk to groundwater – the most probable pathway for future environmental impacts associated with the cleanup of the Hanford site. A recent environmental assessment of Cast Stone performance, which assumes a diffusion controlled release of contaminants from the waste form, calculates groundwater in excess of the allowable maximum permissible concentrations for both contaminants. There is, therefore, a need and an opportunity to improve the retention of both 99Tc and 129I in Cast Stone. One method to improve the performance of Cast Stone is through the addition of “getters” that selectively sequester Tc and I, therefore reducing their diffusion out of Cast Stone. In this paper, we present results of Tc and I removal from solution with various getters. Batch sorption experiments were conducted with deionized water (DIW) and a highly caustic LAW simulant with a 7.8 M average Na concentration. In general, the data show that the selected getters are effective in DIW but their performance is compromised when experiments are performed with the 7.8 M Na Ave LAW simulant. The diminished performance in the LAW simulant may be due to competition with Cr present in the 7.8 M Na Ave LAW simulant and to a pH effect that may create a negatively charged surface that can repel negatively charged species.

We present a methodology to enhance the electrical capacitance of activated carbon (AC) electrodes based on the introduction of electrically charged defects through argon plasma processing. Extensive characterization using electrochemical techniques incorporating cyclic voltammetry, constant current charge/discharge, and electrical impedance spectroscopy indicated a close to seven-fold increase in capacitance with respect to untreated AC electrodes, not subject to plasma processing.

We report on the results of culturing SH-SY5Y neuron-like cells on PEDOT:PSS wrinkled surfaces fabricated by thermally-induced shrinking of commercial polystyrene sheets. Such smart biointerfaces combine the functional properties of conducting polymers with the topographic patterning at the micro- and sub-microscale, as a result of surface wrinkling. By imposing mechanical constraints during shrinking, anisotropic topographic features are formed, with a spatial periodicity in the range 0.7 - 1.2 μm, tunable by varying the thickness of the PEDOT:PSS thin film. The effectiveness of wrinkled surfaces in enhancing and orientating the outgrowth of neurites is demonstrated by a 42% increase in length and by the 85% of neurites aligned along wrinkles direction (angle 0 < θ < 15°), after 5 days of differentiation. Furthermore, the conductive properties of the PEDOT:PSS film are retained after the surface wrinkling, opening the way for the exploitation of these smart biointerfaces for the electrical stimulation of cells.

The effect of Si addition on microstructure and mechanical properties of dual two-phase intermetallic alloys was investigated. Si was added to the base alloy composition Ni75Al9V13Nb3 + 50 wt. ppm B by three substitution ways in which Si was substituted either for Ni, for Al and for V, respectively. The alloys added with 1 at.% Si showed a dual two-phase microstructure composed of Ni3Al (L12) and Ni3V (D022) phases, while the alloys added with over 2 at.% Si exhibited the same dual two-phase microstructure but contained third phases. The third phases were G phase (Ni16Si7Nb6) and A2 phase (the bcc solid solution consisting of Nb and V). Yield and tensile strength of the 1 at.% Si-added alloys were high in the alloy in which Si was substituted for Al but low in the alloys in which Si was substituted for Ni or for V, in comparison with those of the base alloy. Tensile elongation was lower than that of the base alloy irrespective of substitution ways. The density of the Si added alloys was close to or slightly lower than that of the base alloy. Oxidation resistance of the Si added alloy was increased. Si addition to the dual two-phase intermetallic alloys is beneficial for reducing the density and enhancing the oxidation resistance without a harmful reduction of strength properties.

A special class of polymer called dendrons which are repeatedly branched polymers linked together by a network of cascade branched monomers. A composite of these dendritic polymers with linear polymers may have unique physical and chemical properties. Using contact resonance mode of atomic force microscopy we are able to detect the viscoelastic properties of the dendritic formation of the polyethylene oxide (PEO) mixed with Polyvinylpyrrolidone (PVP). PEO is known to form nanometric crystallites due to the diffusion limited aggregation process. However, the dendritic formation in the mixture has not been reported before. The amplitude and phase of the contact resonance shows a clear dendritic growth of PEO in the composite material. The extent of the polymer crystallization can be several nanometers thick within the composite material. Additionally, the intrinsic properties of such polymers to form denrimers can be explored for fabricating polymer composites having numerous potential applications in chemical sensing, drug-delivery, energy applications and many more.

B2 aluminides have a role of Al reservoir for Al2O3 surface and it is expected to increase oxidation resistance of (Nb,Mo)-bccss substrate. For the accumulation of the basic information to design the alloy composed of B2 coating on bccss matrix, bccss - B2 two-phase field was investigated in the Nb-Mo-Ni-Pd-Al system at 1273 K. It is found that Pd-rich B2-(Ni,Pd)Al phase is in equilibrium with Nb-rich bccss phase, while without Pd, the composition range of bccss coexisting with B2-NiAl phase is limited to be low Nb.

The Australian Centre for Advanced Photovoltaics (ACAP) co-ordinates the activities of the six Australian research institutions and a group of industrial partners in the Australia-US Institute for Advanced Photovoltaics (AUSIAPV) to develop the next generations of photovoltaic device technology and to provide a pipeline of opportunities for performance increase and cost reduction. AUSIAPV links ACAP with US-based partners. These national and international research collaborations provide a pathway for highly visible, structured photovoltaic research collaboration between Australian and US researchers, institutes and agencies with significant joint programs based on the clear synergies between the participating organizations. The research program is organized in five collaborative Program Packages (PPs). PP1 deals with silicon wafer-based cells, focusing on three main areas: cells from solar grade silicon, rear contact and silicon-based tandem cells. PP2 involves research into a range of organic solar cells, organic/inorganic hybrid cells, "earth abundant" thin-film materials and "third generation" approaches. PP3 is concerned with optics and characterization. PP4 will deliver a substantiated methodology for assessing manufacturing costs of the different technologies and PP5 involves education, training and outreach. The main research topics, results and plans for the future are presented.

Reactive nanocomposite powders with compositions 2Al∙3CuO, 2.35Al∙Bi2O3, 2Al∙Fe2O3, and 2Al∙MoO3 were prepared by arrested reactive milling, placed in monolayers on a conductive substrate and ignited by an electro-static discharge (ESD) or spark in air, argon, and vacuum. The ESD was produced by discharging a 2000 pF capacitor charged to a voltage varied from 5 to 20 kV. Emission from ignited particles was monitored using a photomultiplier equipped with an interference filter. Experimental variables included particle sizes, milling time used to prepare composite particles, surrounding environment, and starting ESD voltage. All materials ignited in all environments, producing individual burning particles that were ejected from the substrate. The spark duration varied from 1 to 5 µs; the duration of the produced emission pulse was in the range of 80 – 250 µs for all materials studied. The longest emission duration was observed for the nanocomposite thermite using MoO3 as an oxidizer. The reaction rates of the ESD-initiated powders were defined primarily by the scale of mixing of and reactive interface area between the fuel and oxidizer in composite materials rather than by the external particle surface or particle dimensions. In vacuum, particles were heated by ESD while remaining on the substrate until they began generating gas combustion products. In air and argon, particles initially pre-heated by ESD were lifted and accelerated to ca. 100 m/s by the generated shock wave; the airborne particles continued self-heating due to heterogeneous redox reactions.

The growth of CdTe2O5 single crystals using a modified Bridgman technique in a RF furnace was attempted. A platinum/gold crucible was used to melt the powder mixture in a customized insulated chamber to provide an adequate vertical thermal gradient. Growths resulted in mica-shaped single crystals that were extracted and investigated. Some optical and electrical properties were studied. Czochralski (CZ) method was also tried but returned very small crystals at best, whereas evaporation of CdO and/or TeO2 presented another challenge.

We report a highly sensitive pressure sensor fabricated by photo-thermally reduced Graphene oxide (GO) with silver nano wires (AgNWs). Pressure sensors are fabricated in form of the inter-digitated capacitors (IDC) composed of two finger electrodes with pattern width of 500 µm. The fabricated IDCs are compared to the previously reported MEMS-based pressure sensors' sensitivity. The fabricated sensor is easily attachable on any surface for monitoring applied forces or pressure and maintains excellent electrical conductivity under high mechanical stress and thus holds promise for durable bio-medical sensors.

In this work, the formation of d-wave superconducting magnetic vortex is studied within the Bogoliubov-de Gennes formalism and the generalized Hubbard model, which leads to 2N 2 coupled self-consistent equations for a supercell of N×N atoms. These equations determine the spatial variation of the superconducting gap as a function of the electron concentration and electron-electron interactions. The results show that the superconducting states induced by the correlated hopping (Δt 3) are more sensitive to the presence of magnetic field than those induced by attractive nearest-neighbor interaction (V). Furthermore, we calculate the electronic specific heat as a function of the temperature for a given applied magnetic field, whose behavior has a qualitative agreement with experimental data.

I will present a model for a complementary relationship between an undergraduate research program and the undergraduate teaching laboratory in materials science. One clear example is using the teaching laboratory to prepare students to do more independent undergraduate research by emphasizing appropriate skills and knowledge, but there are several others. Undergraduate researchers can work with faculty to develop novel experiments and apparatus that can be used in the teaching laboratory. Undergraduates can gain working knowledge of common research techniques and equipment within their program. The ideas should be applicable to any institution placing a priority on undergraduate research and undergraduate education.

Metamaterial structures composed of ordered arrays of metallic nanoparticles (NPs) and nanocavities are able to support strong plasmon and Fano resonances in the optical frequencies, where the appeared Fano dips can be utilized in bio/chemical sensing and spectroscopic purposes with a significant sensitivity. Herein, we utilize two concentric compositional Aluminum (Al) nanoshells (Al/Al2O3) to design nanomatryushka (NM) structures in periodic arrays, where each one of Al NPs is covered by a certain thickness of the oxide layer. Depositing studied Al NM arrays on metasurfaces, we determined the optical response of the metamaterial. It is shown that the proposed structure is able to support multiple strong Fano resonances in the visible spectrum. Evaluating the plasmon response of the metamaterial configuration for the presence of various semiconductor metasurfaces (Silicon and GaP), the quality of Fano dips is analyzed for different regimes. In this method, we measured the accuracy and sensitivity of the metamaterial structure by plotting the linear figure of merit (FoM) and quantifying this parameter.

Formation of patterned metal and semiconductor (e.g. silicon) nanowires is achieved using anodic aluminum oxide (AAO) templates with porous structures of different heights resulting from an initial step difference made by etching the aluminum (Al) thin film with a photoresist developer prior to the anodization process. This approach allows for the growth of vertically aligned nanowire arrays on a metal substrate, instead of an oriented semiconductor substrate, using an electroplating or a chemical vapor deposition (CVD) process. The vertically aligned metal and semiconductor nanowires defined on a metal substrate could be applied to the realization of vertical 3D transistors, field emission devices, or nano-micro sensors for biological applications.

The importance of ZnxMg1-xO is increasing day by day because of its wider bandgap than ZnO. This ternary semiconductor finds its application in the fields of optoelectronics, spintronics, superlattices due to its unique blueshifted UV-luminescent property. n- to p-type conduction which is the motive of the project can be achieved with increasing Mg content in ZnMgO. The optical characteristics of the nitrogen doped ZnxMg1-xO (x=0.85) grown on 2 inch Si <100>wafer by RF sputtering are studied and analyzed thoroughly using low temperature (15K) photoluminescence measurements. Nitrogen implantation was carried out by Plasma immersion Ion Implantation technique on the sample. Rapid Thermal Process was employed to remove defects resulting from implantation. The samples were annealed at 700°C, 800°C, 900°C, and 1000o C for 10 seconds in an oxygen ambient. Photoluminescence (PL) measurements were performed at low temperature (15K) which exhibited acceptor-bound-exciton peak (A°X) and donor-bound-acceptor pair (DAP) at 3.336 eV and 3.236 eV respectively. At 3.364 eV, S peak was found for the sample annealed at 800°C after implantation. This peak was attributed to the existence of ZnO-like composition. Localized and de-localized exciton peaks were found around 3.42 and 3.45 eV respectively. This result is very important because though dominant acceptor peak was not found but proper optimization of the parameters can lead to p-type ZnMgO which is the main motive of this project.

New low aluminium high niobium TiAl alloys exhibit a nano scale modulated microstructure consisting of lamellae with a tweed substructure. These tweed like appearing lamellae are a modulated arrangement of at least two phases. One constituent of the crystallographic modulation in the lamellae is an orthorhombic phase, which is closely related to both the hexagonal α2-Ti3Al phase and the cubic B2 ordered βo-TiAl phase.

In this study the nature and formation of this orthorhombic phase has been investigated by high-energy X-ray diffraction.

Measurements have shown that the newly formed orthorhombic phase is structurally comparable to the O phase (Ti2AlNb). It forms in the temperature range of 550 °C to 670 °C from the α2 phase by small atomic displacements and chemical reordering. The in situ experiments yielded information about the thermal stability of the orthorhombic phase. After dissolving at temperatures above 700 °C the phase can be re-precipitated by annealing within the temperature range of formation.

Li/S batteries have received too much attention due to their considerable theoretical energy density suitable for high energy applications. Here, we study the consequences of the SEI layer on internal resistance of the single battery cell due to polysulfide (PS) shuttling. The growth in resistance is related to the capacity fading of the cell. Using a model of series resistors, the total internal ionic resistance over cycling performance is expressed and compared for various nanostructured cathodes at different rates. It has been shown that SEI layer is the most significant factor in increasing of ionic resistance at the beginning of the battery aging, while electrode degradation and other phenomena are dominating resistance rise over higher cycles. We also demonstrate that cathodes with smaller equivalent porosity represent an excellent performance in preventing internal resistance enhancement.