Depressed electron collector for the Gatling Gun Test Stand (open access)

Depressed electron collector for the Gatling Gun Test Stand

N/A
Date: October 24, 2013
Creator: A., Pikin; Ben-Zvi, Ilan; Chang, X. Y.; Gassner, D.; Litvinenko, V.; Rahman, O. et al.
Object Type: Report
System: The UNT Digital Library
LEEM investigations of clean surfaces driven by energetic ion beams (open access)

LEEM investigations of clean surfaces driven by energetic ion beams

The original purpose of this award was to use low‐energy electron microscopy (LEEM) to explore the dynamics of surfaces of clean single crystal surfaces when driven by a beam of energetic ions. The goal was to understand the nanoscience of hyperthermal growth, surface erosion by sublimation and irradiation, operation of surface sinks in irradiated materials, diffusion on driven surfaces, and the creation of structural patterns. This project was based on a novel LEEM system constructed by C. P. Flynn, which provided real‐time imaging of surface dynamics by scattering low energy electrons. With the passing of Prof. Flynn in late 2011, this project was completed under a slightly different scope by constructing a low‐energy, inelastic electron scattering (�EELS�) instrument. Consistent with Flynn�s original objectives for his LEEM system, this device probes the dynamics of crystal surfaces. However the measurements are not carried out in real time, but instead are done in the frequency domain, through the energy lost from the probe electrons. The purpose of this device is to study the collective bosonic excitations in a variety of materials, including high temperature superconductors, topological insulators, carbon allotropes including (but not limited to) graphene, etc. The ultimate goal here is to identify …
Date: April 24, 2013
Creator: Abbamonte, Peter M.
Object Type: Report
System: The UNT Digital Library
A METHODOLOGY FOR DETERMINING THE DOSE RATE FOR BOUNDING MASS LIMITS IN A 9977 PACKAGING (open access)

A METHODOLOGY FOR DETERMINING THE DOSE RATE FOR BOUNDING MASS LIMITS IN A 9977 PACKAGING

The Small Gram Quantity (SGQ) concept is based on the understanding that the hazards associated with the shipment of a radioactive material are directly proportional to its mass. This study describes a methodology that estimates the acceptable masses for several neutron and gamma emitting isotopes that can be shipped in a 9977 Package compliant with the Title 10 of the Code of Federal Regulations, Part 71 (10CFR71) external radiation level limits. 10CFR71.33 states that a shipping application identifies the radioactive and fissile materials at their maximum quantity and provides an evaluation demonstrating compliance with the external radiation standards. Since rather small amounts of some isotopes emit sufficiently strong radiation to produce a large external dose rate, quantifying of the dose rate for a proposed content is a challenging issue for the SGQ approach. It is essential to quantify external radiation levels from several common gamma and neutron sources that can be safely placed in a specific packaging, to ensure compliance with federal regulations. A methodology was established for determining the dose rate for bounding mass limits for a set of isotopes in the Model 9977 Shipping Package. Calculations were performed to estimate external radiation levels using the MCNP radiation transport …
Date: May 24, 2012
Creator: Abramczyk, G.; Bellamy, S.; Nathan, S. & Loftin, B.
Object Type: Article
System: The UNT Digital Library
INDEPENDENT VERIFICATION SURVEY REPORT FOR THE OPERABLE UNIT-1 LANDFILL TRENCHES, MIAMISBURG CLOSURE PROJECT (open access)

INDEPENDENT VERIFICATION SURVEY REPORT FOR THE OPERABLE UNIT-1 LANDFILL TRENCHES, MIAMISBURG CLOSURE PROJECT

INDEPENDENT VERIFICATION SURVEY REPORT FOR THE OPERABLE UNIT-1 LANDFILL TRENCHES, MIAMISBURG CLOSURE PROJECT, MIAMISBURG, OHIO DCN: 0468-SR-02-0
Date: May 24, 2010
Creator: Adams, W. C.
Object Type: Report
System: The UNT Digital Library
LETTER REPORT. INDEPENDENT CONFIRMATORY SURVEY RESULTS OF SOILS ASSOCIATED WITH THE ARGYLE STREET SEWER LINE AT THE UNITED NUCLEAR CORPORATION NAVAL PRODUCTS SITE, NEW HAVEN, CONNECTICUT (open access)

LETTER REPORT. INDEPENDENT CONFIRMATORY SURVEY RESULTS OF SOILS ASSOCIATED WITH THE ARGYLE STREET SEWER LINE AT THE UNITED NUCLEAR CORPORATION NAVAL PRODUCTS SITE, NEW HAVEN, CONNECTICUT

Oak Ridge Institute for Science and Education (ORISE) personnel visited the United Nuclear Corporation (UNC) Naval Products site on three separate occasions during the months of October and November 2011. The purpose of these visits was to conduct confirmatory surveys of soils associated with the Argyle Street sewer line that was being removed. Soil samples were collected from six different, judgmentally determined locations in the Argyle Street sewer trench. In addition to the six soil samples collected by ORISE, four replicate soil samples were collected by Cabrera Services, Inc. (CSI) for analysis by the ORISE laboratory. Replicate samples S0010 and S0011 were final status survey (FSS) bias samples; S0012 was an FSS systematic sample; and S0015 was a waste characterization sample. Six soil samples were also collected for background determination. Uranium-235 and uranium-238 concentrations were determined via gamma spectroscopy; the spectra were also reviewed for other identifiable photopeaks. Radionuclide concentrations for these soil samples are provided. In addition to the replicate samples and the samples collected by ORISE, CSI submitted three soil samples for inter-laboratory comparison analyses. One sample was from the background reference area, one was from waste characterization efforts (material inside the sewer line), and one was a …
Date: January 24, 2012
Creator: Adams, Wade C.
Object Type: Report
System: The UNT Digital Library
Report of the First Confidence Building Exercise For Biomedical Sample Analysis (open access)

Report of the First Confidence Building Exercise For Biomedical Sample Analysis

We participated in the first exercise to build confidence in the analysis of biomedical samples for trace levels of CW agents and/or their degradation, reaction or metabolites.
Date: February 24, 2010
Creator: Alcaraz, A. & Gregg, H.
Object Type: Report
System: The UNT Digital Library
ION EXCHANGE PERFORMANCE OF TITANOSILICATES, GERMANATES AND CARBON NANOTUBES (open access)

ION EXCHANGE PERFORMANCE OF TITANOSILICATES, GERMANATES AND CARBON NANOTUBES

This report presents a summary of testing the affinity of titanosilicates (TSP), germanium-substituted titanosilicates (Ge-TSP) and multiwall carbon nanotubes (MWCNT) for lanthanide ions in dilute nitric acid solution. The K-TSP ion exchanger exhibited the highest affinity for lanthanides in dilute nitric acid solutions. The Ge-TSP ion exchanger shows promise as a material with high affinity, but additional tests are needed to confirm the preliminary results. The MWCNT exhibited much lower affinities than the K-TSP in dilute nitric acid solutions. However, the MWCNT are much more chemically stable to concentrated nitric acid solutions and, therefore, may candidates for ion exchange in more concentrated nitric acid solutions. This technical report serves as the deliverable documenting completion of the FY13 research milestone, M4FT-13SR0303061 – measure actinide and lanthanide distribution values in nitric acid solutions with sodium and potassium titanosilicate materials.
Date: April 24, 2013
Creator: Alsobrook, A. & Hobbs, D.
Object Type: Report
System: The UNT Digital Library
Ion Separation Effects in Mixed-Species Ablator and Fuels for Inertial Confinement Fusion Implosions (open access)

Ion Separation Effects in Mixed-Species Ablator and Fuels for Inertial Confinement Fusion Implosions

None
Date: June 24, 2013
Creator: Amendt, P.; Bellei, C.; Ross, J. S.; Salmonson, J. & Wilks, S.
Object Type: Article
System: The UNT Digital Library
A Seemingly Simple Task: Filling a Solenoid Volume in Vacuum with Dense Plasma (open access)

A Seemingly Simple Task: Filling a Solenoid Volume in Vacuum with Dense Plasma

Space-charge neutralization of a pulsed, high-current ion beam is required to compress and focus the beam on a target for warm dense matter physics or heavy ion fusion experiments. We described attempts to produce dense plasma in and near the final focusing solenoid through which the ion beam travels, thereby providing an opportunity for the beam to acquire the necessary charge-compensating electrons. Among the options are plasma injection from four pulsed vacuum arc sources located outside the solenoid, and using a high current (> 4 kA) pulsed vacuum arc plasma from a ring cathode near the edge of the solenoid. The plasma distribution is characterized by photographic means and by an array of movable Langmuir probes. The plasma is produced at several cathode spots distributed azimuthally on the ring cathode. Beam neutralization and compression are accomplished, though issues of density, uniformity, and pulse-to-pulse reproducibly remain to be solved.
Date: June 24, 2010
Creator: Anders, Andre; Kauffeldt, Marina; Roy, Prabir & Oks, Efim
Object Type: Article
System: The UNT Digital Library
TORUS: Theory of Reactions for Unstable iSotopes Annual Continuation and Progress Report Year-2: March 1, 2011 - February 29, 2012 (open access)

TORUS: Theory of Reactions for Unstable iSotopes Annual Continuation and Progress Report Year-2: March 1, 2011 - February 29, 2012

The TORUS collaboration derives its name from the research it focuses on, namely the Theory of Reactions for Unstable iSotopes. It is a Topical Collaboration in Nuclear Theory, and funded by the Nuclear Theory Division of the Office of Nuclear Physics in the Office of Science of the Department of Energy. The funding supports one postdoctoral researcher for the years 1 through 3. The collaboration brings together as Principal Investigators a large fraction of the nuclear reaction theorists currently active within the USA. The mission of the TORUS Topical Collaboration is to develop new methods that will advance nuclear reaction theory for unstable isotopes by using three-body techniques to improve direct-reaction calculations, and, by using a new partial-fusion theory, to integrate descriptions of direct and compound-nucleus reactions. This multi-institution collaborative effort is directly relevant to three areas of interest: the properties of nuclei far from stability; microscopic studies of nuclear input parameters for astrophysics, and microscopic nuclear reaction theory.
Date: February 24, 2012
Creator: Arbanas, Goran; Elster, Charlotte; Escher, Jutta; Mukhamedzanov, Akram; Nunes, Filomena & Thompson, Ian J.
Object Type: Report
System: The UNT Digital Library
TORUS: Theory of Reactions for Unstable iSotopes - Year 1 Continuation and Progress Report (open access)

TORUS: Theory of Reactions for Unstable iSotopes - Year 1 Continuation and Progress Report

The TORUS collaboration derives its name from the research it focuses on, namely the Theory of Reactions for Unstable iSotopes. It is a Topical Collaboration in Nuclear Theory, and funded by the Nuclear Theory Division of the Office of Nuclear Physics in the Office of Science of the Department of Energy. The funding started on June 1, 2010, it will have been running for nine months by the date of submission of this Annual Continuation and Progress Report on March 1, 2011. The extent of funding was reduced from the original application, and now supports one postdoctoral researcher for the years 1 through 3. The collaboration brings together as Principal Investigators a large fraction of the nuclear reaction theorists currently active within the USA. The mission of the TORUS Topical Collaboration is to develop new methods that will advance nuclear reaction theory for unstable isotopes by using three-body techniques to improve direct-reaction calculations, and, by using a new partial-fusion theory, to integrate descriptions of direct and compound-nucleus reactions. This multi-institution collaborative effort is directly relevant to three areas of interest: the properties of nuclei far from stability; microscopic studies of nuclear input parameters for astrophysics, and microscopic nuclear reaction theory.
Date: February 24, 2011
Creator: Arbanas, Goran; Elster, Charlotte; Escher, Jutta; Mukhamedzhanov, Akram; Nunes, Filomena & Thompson, Ian J.
Object Type: Report
System: The UNT Digital Library
MODIS Airborne simulator (MAS) Final Report for CLASIC (open access)

MODIS Airborne simulator (MAS) Final Report for CLASIC

The MAS was flown aboard the NASA ER-2 for the CLASIC field experiment, and for all data collected, provided calibrated and geolocated (Level-1B) radiance data for it’s 50 spectral bands (ranging in wavelength for 0.47 to 14.3 µm). From the Level-1B data, as directed in the Statement of Work, higher order (Level-2) data products were derived. The Level-2 products include: a) cloud optical thickness, b) cloud effective radius, c) cloud top height (temperature), d) cloud fraction, e) cloud phase products. Preliminary Level-1B and Level-2 products were provided during the field experiment (typically within one or two days of data collection). Final version data products were made available in December 2008 following considerable calibration analysis. Data collection, data processing (to Level-2), and discussion of the calibration work are summarized below.
Date: November 24, 2010
Creator: Arnold, Thomas & Platnick, Steven
Object Type: Report
System: The UNT Digital Library
Opportunities for Drell-Yan Physics at RHIC (open access)

Opportunities for Drell-Yan Physics at RHIC

Drell-Yan (DY) physics gives the unique opportunity to study the parton structure of nucleons in an experimentally and theoretically clean way. With the availability of polarized proton-proton collisions and asymmetric d+Au collisions at the Relativistic Heavy Ion Collider (RHIC), we have the basic (and unique in the world) tools to address several fundamental questions in QCD, including the expected gluon saturation at low partonic momenta and the universality of transverse momentum dependent parton distribution functions. A Drell-Yan program at RHIC is tied closely to the core physics questions of a possible future electron-ion collider, eRHIC. The more than 80 participants of this workshop focused on recent progress in these areas by both theory and experiment, trying to address imminent questions for the near and mid-term future.
Date: May 24, 2011
Creator: Aschenauer, E.; Bland, L.; Crawford, H.; Goto, Y.; Eyser, O.; Kang, Z. et al.
Object Type: Report
System: The UNT Digital Library
Cellular response to low dose radiation: Role of phosphatidylinositol-3 kinase like kinases (open access)

Cellular response to low dose radiation: Role of phosphatidylinositol-3 kinase like kinases

It is increasingly realized that human exposure either to an acute low dose or multiple chronic low doses of low LET radiation has the potential to cause different types of cancer. Therefore, the central theme of research for DOE and NASA is focused on understanding the molecular mechanisms and pathways responsible for the cellular response to low dose radiation which would not only improve the accuracy of estimating health risks but also help in the development of predictive assays for low dose radiation risks associated with tissue degeneration and cancer. The working hypothesis for this proposal is that the cellular mechanisms in terms of DNA damage signaling, repair and cell cycle checkpoint regulation are different for low and high doses of low LET radiation and that the mode of action of phosphatidylinositol-3 kinase like kinases (PIKK: ATM, ATR and DNA-PK) determines the dose dependent cellular responses. The hypothesis will be tested at two levels: (I) Evaluation of the role of ATM, ATR and DNA-PK in cellular response to low and high doses of low LET radiation in simple in vitro human cell systems and (II) Determination of radiation responses in complex cell microenvironments such as human EpiDerm tissue constructs. Cellular …
Date: March 24, 2011
Creator: Balajee, A. S.; Meador, J. A. & Su, Y.
Object Type: Report
System: The UNT Digital Library
An Evaluation of a Structured Overlapping Grid Implementation of FCT for High-Speed Flows (open access)

An Evaluation of a Structured Overlapping Grid Implementation of FCT for High-Speed Flows

None
Date: August 24, 2011
Creator: Banks, J. W. & Shadid, J. N.
Object Type: Book
System: The UNT Digital Library
Photoacoustically Measured Speeds of Sound of Liquid HBO2: On Unlocking the Fuel Potential of Boron (open access)

Photoacoustically Measured Speeds of Sound of Liquid HBO2: On Unlocking the Fuel Potential of Boron

Elucidation of geodynamic, geochemical, and shock induced processes is often limited by challenges to accurately determine molecular fluid equations of state (EOS). High pressure liquid state reactions of carbon species underlie physiochemical mechanisms such as differentiation of planetary interiors, deep carbon sequestration, propellant deflagration, and shock chemistry. Here we introduce a versatile photoacoustic technique developed to measure accurate and precise speeds of sound (SoS) of high pressure molecular fluids and fluid mixtures. SoS of an intermediate boron oxide, HBO{sub 2} are measured up to 0.5 GPa along the 277 C isotherm. A polarized Exponential-6 interatomic potential form, parameterized using our SoS data, enables EOS determinations and corresponding semi-empirical evaluations of > 2000 C thermodynamic states including energy release from bororganic formulations. Our thermochemical model propitiously predicts boronated hydrocarbon shock Hugoniot results.
Date: March 24, 2010
Creator: Bastea, S.; Crowhurst, J.; Armstrong, M. & Teslich, Nick, Jr.
Object Type: Article
System: The UNT Digital Library
Ground Source Integrated Heat Pump (GS-IHP) Development (open access)

Ground Source Integrated Heat Pump (GS-IHP) Development

Between October 2008 and May 2013 ORNL and ClimateMaster, Inc. (CM) engaged in a Cooperative Research and Development Agreement (CRADA) to develop a groundsource integrated heat pump (GS-IHP) system for the US residential market. A initial prototype was designed and fabricated, lab-tested, and modeled in TRNSYS (SOLAR Energy Laboratory, et al, 2010) to predict annual performance relative to 1) a baseline suite of equipment meeting minimum efficiency standards in effect in 2006 (combination of air-source heat pump (ASHP) and resistance water heater) and 2) a state-of-the-art (SOA) two-capacity ground-source heat pump with desuperheater water heater (WH) option (GSHPwDS). Predicted total annual energy savings, while providing space conditioning and water heating for a 2600 ft{sup 2} (242 m{sup 2}) house at 5 U.S. locations, ranged from 52 to 59%, averaging 55%, relative to the minimum efficiency suite. Predicted energy use for water heating was reduced 68 to 78% relative to resistance WH. Predicted total annual savings for the GSHPwDS relative to the same baseline averaged 22.6% with water heating energy use reduced by 10 to 30% from desuperheater contributions. The 1st generation (or alpha) prototype design for the GS-IHP was finalized in 2010 and field test samples were fabricated for testing …
Date: May 24, 2013
Creator: Baxter, V. D.; Rice, K.; Murphy, R.; Munk, J.; Ally, Moonis; Shen, Bo et al.
Object Type: Report
System: The UNT Digital Library
Survey of Laser Markets Relevant to Inertial Fusion Energy Drivers, information for National Research Council (open access)

Survey of Laser Markets Relevant to Inertial Fusion Energy Drivers, information for National Research Council

Development of a new technology for commercial application can be significantly accelerated by leveraging related technologies used in other markets. Synergies across multiple application domains attract research and development (R and D) talent - widening the innovation pipeline - and increases the market demand in common components and subsystems to provide performance improvements and cost reductions. For these reasons, driver development plans for inertial fusion energy (IFE) should consider the non-fusion technology base that can be lveraged for application to IFE. At this time, two laser driver technologies are being proposed for IFE: solid-state lasers (SSLs) and KrF gas (excimer) lasers. This document provides a brief survey of organizations actively engaged in these technologies. This is intended to facilitate comparison of the opportunities for leveraging the larger technical community for IFE laser driver development. They have included tables that summarize the commercial organizations selling solid-state and KrF lasers, and a brief summary of organizations actively engaged in R and D on these technologies.
Date: February 24, 2011
Creator: Bayramian, A. J.; Deri, R. J. & Erlandson, A. C.
Object Type: Report
System: The UNT Digital Library
Steering the Self-Assembly of Octadecylamine Monolayers on Mica by Controlled Mechanical Energy Transfer from the AFM Tip (open access)

Steering the Self-Assembly of Octadecylamine Monolayers on Mica by Controlled Mechanical Energy Transfer from the AFM Tip

We have studied the effect of mechanical energy transfer from the tip of an Atomic Force Microscope on the dynamics of self-assembly of monolayer films of octadecylamine on mica. The formation of the self-assembled film proceeds in two successive stages, the first being a fast adsorption from solution that follows a Langmuir isotherm. The second is a slower process of island growth by aggregation of the molecules dispersed on the surface. We found that the dynamics of aggregation can be altered substantially by the addition of mechanical energy into the system through controlled tip-surface interactions. This leads to either the creation of pinholes in existing islands as a consequence of vacancy concentration, and to the assembly of residual molecules into more compact islands.
Date: June 24, 2010
Creator: Benitez, J.J.; Heredia-Guerrero, J.A. & Salmeron, M.
Object Type: Article
System: The UNT Digital Library
Final Report (open access)

Final Report

This project combines outcrop-scale heterogeneity characterization, laboratory experiments, and numerical simulations. The study is designed to test whether established dispersion theory accurately predicts the behavior of solute transport through heterogeneous media and to investigate the relationship between heterogeneity and the parameters that populate these models. The dispersion theory tested by this work is based upon the fractional advection-dispersion equation (fADE) model. Unlike most dispersion studies that develop a solute transport model by fitting the solute transport breakthrough curve, this project will explore the nature of the heterogeneous media to better understand the connection between the model parameters and the aquifer heterogeneity. Our work at the Colorado School of Mines was focused on the following questions: 1) What are the effects of multi-scale geologic variability on transport of conservative and reactive solutes? 2) Can those transport effects be accounted for by classical methods, and if not, can the nonlocal fractional-order equations provide better predictions? 3) Can the fractional-order equations be parameterized through a link to some simple observable geologic features? 4) Are the classical equations of transport and reaction sufficient? 5) What is the effect of anomalous transport on chemical reaction in groundwater systems? The work is predicated on the observation …
Date: September 24, 2012
Creator: Benson, David A.
Object Type: Report
System: The UNT Digital Library
Using a Relativistic Electron Beam to Generate Warm Dense Matter for Equation of State Studies (open access)

Using a Relativistic Electron Beam to Generate Warm Dense Matter for Equation of State Studies

Experimental equation-of-state (EOS) data are difficult to obtain for warm dense matter (WDM)–ionized materials at near-solid densities and temperatures ranging from a few to tens of electron volts–due to the difficulty in preparing suitable plasmas without significant density gradients and transient phenomena. We propose that the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility can be used to create a temporally stationary and spatially uniform WDM. DARHT has an 18 MeV electron beam with 2 kA of current and a programmable pulse length of 20 ns to 200 ns. This poster describes how Monte Carlo n-Particle (MCNP) radiation transport and LASNEX hydrodynamics codes were used to demonstrate that the DARHT beam is favorable for avoiding the problems that have hindered past attempts to constrain WDM properties. In our concept, a 60 ns pulse of electrons is focused onto a small, cylindrical (1 mm diameter × 1 mm long) foam target, which is inside a stiff high-heat capacity tube that both confines the WDM and allows pressure measurements. In our model, the foam is made of 30% density Au and the tamper is a B4C tube. An MCNP model of the DARHT beam investigated electron collisions and the amount of energy deposited …
Date: June 24, 2011
Creator: Berninger, M.
Object Type: Article
System: The UNT Digital Library
Design of a 10**36 CM-2 S-1 Super-B Factory (open access)

Design of a 10**36 CM-2 S-1 Super-B Factory

Parameters have been studied for a high luminosity e{sup +}e{sup -} collider operating at the Upsilon 4S that would deliver a luminosity of 1 to 4 x 10{sup 36}/cm{sup 2}/s. This collider, called a Super-B Factory, would use a combination of linear collider and storage ring techniques. In this scheme an electron beam and a positron beam are stored in low-emittance damping rings similar to those designed for a Linear Collider (LC) or the next generation light source. A LC style interaction region is included in the ring to produce sub-millimeter vertical beta functions at the collision point. A large crossing angle (+/- 24 mrad) is used at the collision point to allow beam separation. A crab-waist scheme is used to reduce the hourglass effect and restore peak luminosity. Beam currents of 1.8 A at 4 x 7 GeV in 1251 bunches can produce a luminosity of 10{sup 36}/cm{sup 2}/s with upgrade possibilities. Such a collider would produce an integrated luminosity of about 10,000 fb{sup -1} (10 ab{sup -1}) in a running year (10{sup 7} sec) at the {gamma}(4S) resonance. Further possibilities include having longitudinally polarized e- at the IR and operating at the J/Psi and Psi beam energies.
Date: October 24, 2011
Creator: Biagini, M.E.; Boni, R.; Boscolo, M.; Demma, T.; Drago, A.; Guiducci, S. et al.
Object Type: Article
System: The UNT Digital Library
Assessment of Non-traditional Isotopic Ratios by Mass Spectrometry for Analysis of Nuclear Activities. Annual Report 2011 (open access)

Assessment of Non-traditional Isotopic Ratios by Mass Spectrometry for Analysis of Nuclear Activities. Annual Report 2011

None
Date: August 24, 2011
Creator: Biegalski, S. R. & Buchholz, B. A.
Object Type: Report
System: The UNT Digital Library
ALD Functionalized Nanoporous Gold: Thermal Stability, Mechanical Properties, and Catalytic Activity (open access)

ALD Functionalized Nanoporous Gold: Thermal Stability, Mechanical Properties, and Catalytic Activity

Nanoporous metals have many technologically promising applications but their tendency to coarsen limits their long-term stability and excludes high temperature applications. Here, we demonstrate that atomic layer deposition (ALD) can be used to stabilize and functionalize nanoporous metals. Specifically, we studied the effect of nanometer-thick alumina and titania ALD films on thermal stability, mechanical properties, and catalytic activity of nanoporous gold (np-Au). Our results demonstrate that even only one-nm-thick oxide films can stabilize the nanoscale morphology of np-Au up to 1000 C, while simultaneously making the material stronger and stiffer. The catalytic activity of np-Au can be drastically increased by TiO{sub 2} ALD coatings. Our results open the door to high temperature sensor, actuator, and catalysis applications and functionalized electrodes for energy storage and harvesting applications.
Date: March 24, 2011
Creator: Biener, M M; Biener, J; Wichmann, A; Wittstock, A; Baumann, T F; Baeumer, M et al.
Object Type: Article
System: The UNT Digital Library