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Sample records for nt ti ia

  1. REPORT NT-15-1

    National Nuclear Security Administration (NNSA)

    REPORT NT-15-1 MAY 2015 ENVIRONMENTAL MONITORING AND DISPOSAL OF RADIOACTIVE WASTES FROM U.S. NAVAL NUCLEAR-POWERED SHIPS AND THEIR SUPPORT FACILITIES NAVAL NUCLEAR PROPULSION ...

  2. IA Experts Listing 2014 | Department of Energy

    Energy Savers [EERE]

    IA Experts Listing 2014 IA Experts Listing 2014 PDF icon IA Experts Listing January 2014 More Documents & Publications Office of International Affairs Organization Chart PI...

  3. Rolling Hills (IA) | Open Energy Information

    Open Energy Info (EERE)

    Rolling Hills (IA) Jump to: navigation, search Name Rolling Hills (IA) Facility Rolling Hills (IA) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service...

  4. Steamboat IA Geothermal Facility | Open Energy Information

    Open Energy Info (EERE)

    IA Geothermal Facility Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Steamboat IA Geothermal Facility General Information Name Steamboat IA Geothermal Facility...

  5. Puff/Plume for Windows 95-NT

    Energy Science and Technology Software Center (OSTI)

    1998-05-20

    PFPL-NT is a GUI event-driven scientific application integrating 14 background processes to access the consequences of accidental releases of hazardous materials from production facilities and transportation vehicles. A simple straight-line Gaussian assumption has been employed with observations from meteorological towers to calculate and visually display plume directions, plume width, and dose/concentration estimates in the immediate vicinity of a radiological or chemical release.

  6. Microsoft Word - BoNT-Stevens.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Defining How Botulinum Toxin Binds to the Synaptotagmin Receptor and Creating Improved Therapeutics to Block Toxicity Botulinum neurotoxin (BoNT), the most potent toxin known, induces a potentially fatal paralytic condition known as "botulism". Botulism can occur when toxin-producing bacteria infect wounds (wound botulism) or the intestinal tract (infant/intestinal botulism), or fol- lowing the ingestion of contaminated food in which toxin has been produced (food-borne botulism). In

  7. Strength and Fatigue of NT551 Silicon Nitride and NT551 Diesel Exhaust Valves

    SciTech Connect (OSTI)

    Andrews, M.J.; Wereszczak, A.A.; Kirkland, T.P.; Breder, K.

    2000-02-01

    The content of this report is excerpted from Mark Andrew's Ph.D. Thesis (Andrews, 1999), which was funded by a DOEYOTT High Temperature Materials Laboratory Graduate Fellowship. It involves the characterization of NT551 and valves fabricated with it. Greater detail of the described issues may be found in that reference or through communications with Andrew Wereszczak.

  8. DE-FC26-06NT42877 - DE-FC26-02NT41628 - DE-FC26-00NT40920 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Gulf of Mexico Gas Hydrates Sea-floor Observatory Project Last Reviewed 12/18/2013 DE-FE26-06NT42877, DE-FC26-02NT41628, and DE-FC26-00NT40920 Goal The goal of this project is to conduct activities leading to the development, implementation, and operation of a remote, multi-sensor seafloor observatory focused on behavior of the marine hydrocarbon system within the gas hydrate stability zone of the deepwater Gulf of Mexico and analysis of data resultant from that observatory over time. Attaining

  9. Strength and fatigue of NT551 silicon nitride and NT551 diesel exhaust valves

    SciTech Connect (OSTI)

    Andrews, M.J.; Werezczak, A.A.; Kirkland, T.P.; Breder, K.

    2000-02-01

    The content of this report is excerpted from Mark Andrew's Ph.D. Thesis (Andrews, 1999), which was funded by a DOE/OTT High Temperature Materials Laboratory Graduate Fellowship. It involves the characterization of NT551 and valves fabricated with it. The motivations behind using silicon nitride (Si{sub 3}N{sub 4}) as an exhaust valve for a diesel engine are presented in this section. There are several economic factors that have encouraged the design and implementation of ceramic components for internal combustion (IC) engines. The reasons for selecting the diesel engine valve for this are also presented.

  10. DE-NT0005669 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    9 Heat flow and gas hydrates on the continental margin of India DE-NT0005669 Last Reviewed ... The goals of this project are to construct maps of apparent and residual heat flow through ...

  11. Category:Mason, IA | Open Energy Information

    Open Energy Info (EERE)

    Mason, IA Jump to: navigation, search Go Back to PV Economics By Location Media in category "Mason, IA" The following 16 files are in this category, out of 16 total....

  12. Defining photometric peculiar type Ia supernovae

    SciTech Connect (OSTI)

    González-Gaitán, S.; Pignata, G.; Förster, F.; Gutiérrez, C. P.; Bufano, F.; Galbany, L.; Hamuy, M.; De Jaeger, T.; Hsiao, E. Y.; Phillips, M. M.; Folatelli, G.; Anderson, J. P.

    2014-11-10

    We present a new photometric identification technique for SN 1991bg-like type Ia supernovae (SNe Ia), i.e., objects with light curve characteristics such as later primary maxima and the absence of a secondary peak in redder filters. This method is capable of selecting this sub-group from the normal type Ia population. Furthermore, we find that recently identified peculiar sub-types such as SNe Iax and super-Chandrasekhar SNe Ia have photometric characteristics similar to 91bg-like SNe Ia, namely, the absence of secondary maxima and shoulders at longer wavelengths, and can also be classified with our technique. The similarity of these different SN Ia sub-groups perhaps suggests common physical conditions. This typing methodology permits the photometric identification of peculiar SNe Ia in large upcoming wide-field surveys either to study them further or to obtain a pure sample of normal SNe Ia for cosmological studies.

  13. HYDRAULICS AND MIXING EVALUATIONS FOR NT-21/41 TANKS

    SciTech Connect (OSTI)

    Lee, S.; Barnes, O.

    2014-11-17

    The hydraulic results demonstrate that pump head pressure of 20 psi recirculates about 5.6 liters/min flowrate through the existing 0.131-inch orifice when a valve connected to NT-41 is closed. In case of the valve open to NT-41, the solution flowrates to HB-Line tanks, NT-21 and NT-41, are found to be about 0.5 lpm and 5.2 lpm, respectively. The modeling calculations for the mixing operations of miscible fluids contained in the HB-Line tank NT-21 were performed by taking a three-dimensional Computational Fluid Dynamics (CFD) approach. The CFD modeling results were benchmarked against the literature results and the previous SRNL test results to validate the model. Final performance calculations were performed for the nominal case by using the validated model to quantify the mixing time for the HB-Line tank. The results demonstrate that when a pump recirculates a solution volume of 5.7 liters every minute out of the 72-liter tank contents containing two acid solutions of 2.7 M and 0 M concentrations (i.e., water), a minimum mixing time of 1.5 hours is adequate for the tank contents to get the tank contents adequately mixed. In addition, the sensitivity results for the tank contents of 8 M existing solution and 1.5 M incoming species show that the mixing time takes about 2 hours to get the solutions mixed.

  14. Pseudocapacitive Lithium-Ion Storage in Oriented Anatase TiO2 Nanotube Arrays

    SciTech Connect (OSTI)

    Zhu, K.; Wang, Q.; Kim, J. H.; Pesaran, A. A.; Frank, A. J.

    2012-06-07

    We report on the synthesis and electrochemical properties of oriented anatase TiO{sub 2} nanotube (NT) arrays as electrodes for Li-ion batteries. The TiO{sub 2} NT electrodes displayed both pseudocapacitive Li{sup +} storage associated with the NT surface and the Li{sup +} storage within the bulk material. The relative contribution of the pseudocapacitive and bulk storages depends strongly on the scan rate. While the charges are stored primarily in the bulk at low scan rates (<< 1 mV/s), the surface storage dominates the total storage capacity at higher scan rates (>1 mV/s). The storage capacity of the NT electrodes as a function of charge/discharge rates showed no dependence on the NT film thickness, suggesting that the Li{sup +} insertion/extraction processes occur homogeneously across the entire length of NT arrays. These results indicated that the electron conduction along the NT walls and the ion conduction within the electrolyte do not cause significant hindering of the charge/discharge kinetics for NT electrode architectures. As a result of the surface pseudocapacitive storage, the reversible Li{sup +} storage capacities for TiO{sub 2} NT electrodes were higher than the theoretical storage capacity for bulk anatase TiO{sub 2} materials.

  15. DE-NT0005638 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    DE-NT0005638 Remote Sensing and Sea-Truth Measurements of Methane Flux to the Atmosphere DE-NT0005638 Last Reviewed 2/23/2012 Project Goal The goal of this project is to improve estimates of methane flux from submarine seeps and associated gas hydrate deposits on continental margins by compiling a remote sensing inventory of active gas and oil vents, and completing sea-truth measurement of flux from representative vents in the Gulf of Mexico. Proposed study sites GC184 (540m), GC852 (1400m),

  16. DE-NT0005666 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    DE-NT0005666 Characterization of Methane Degradation and Methane-Degrading Microbes in Alaska Coastal Waters DE-NT0005666 Last Reviewed 5/15/2012 Project Goal The goal of this project is gain a better understanding of methane degradation and methane-degrading microbes in order to improve predictive models of methane fluxes in the Arctic. Performer University of Delaware, College of Marine and Earth Studies, Lewes, DE 19968 Map of proposed study area. The area boxed in red is the main region to

  17. DE-NT0006558 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    DE-NT0006558 Integrating Natural Gas Hydrates in the Global Carbon Cycle DE-NT0006558 Last Reviewed 5/29/2012 Project Goal The goal of this project is to develop a two-dimensional, basin-scale model for the deep sediment biosphere with methane dynamics to provide a better picture of the distribution of hydrates on the sea floor and their vulnerability to warming of the deep ocean, thus integrating methane hydrates into the global carbon cycle. Performers University of Chicago - Chicago, IL 60637

  18. IA Blog Archive | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Blog Archive IA Blog Archive RSS May 31, 2016 IA Blog Archive Global Energy Leaders Gather in California to Drive Clean Energy Development and Deployment Goal of meetings will be to expand international collaboration in clean energy research, development, demonstration and deployment to combat climate change. May 18, 2016 IA Blog Archive 10 Ways the Clean Energy Ministerial Is Speeding Up the World's Clean Energy Revolution The world needs a lot more clean energy, and fast. Here are 10 ways the

  19. DE-NT-0004654 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The Instrumented Pipeline Initiative DE-NT-0004654 Goal The goal of the Instrumented Pipeline Initiative (IPI) is to address sensor system needs for low-cost monitoring and inspection as identified in the Department of Energy (DOE) National Gas Infrastructure Research & Development (R&D) Delivery Reliability Program Roadmap. This project intends to develop a new sensing and continuous monitoring system with alternative use as an inspection method. Performers Concurrent Technologies

  20. DE-NT0005667 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    DOE/NETL Methane Hydrate Projects Assessing the Efficacy of the Aerobic Methanotropic Biofilter in Methane Hydrate Environments Last Reviewed 1/8/2013 DE-NT0005667 Goal The goal of this project is to assess the efficacy of aerobic methanotrophy in preventing the escape of methane from marine, hydrate-bearing reservoirs to the atmosphere and ultimately to better define the role of aerobic methanotrophy in the global carbon cycle. Methane seeps with the resulting methane plume, Geophysical

  1. DE-NT0005683 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    North Slope Decision Support for Water Resource Planning and Management Last Reviewed 6/26/2013 DE-NT0005683 Goal The goal of this project is to develop a general scientific, engineering, and technological support system for water resources planning and management related to oil and gas development on the North Slope of Alaska. Such a system will aid in developing solutions to economic, environmental, and cultural concerns. Performers University of Alaska Fairbanks Systems, Fairbanks, AK

  2. DOE - Office of Legacy Management -- Titus Metals - IA 04

    Office of Legacy Management (LM)

    Titus Metals - IA 04 FUSRAP Considered Sites Site: TITUS METALS ( IA.04 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Waterloo , Iowa IA.04-1 Evaluation Year: 1987 IA.04-2 Site Operations: Extruded uranium billets to produce fuel plates for the Argonaut reactor in June, 1956. IA.04-1 IA.04-2 Site Disposition: Eliminated - Potential for contamination considered remote based on the limited scope of activities at the site and results of

  3. New approaches for modeling type Ia supernovae (Conference) ...

    Office of Scientific and Technical Information (OSTI)

    Type Ia supernovae (SNe Ia) are the largest thermonuclearexplosions in the Universe. Their light output can be seen across greatstances and has led to the discovery that the ...

  4. ASTRONOMY AND ASTROPHYSICS Dark Energy, Type Ia supernovae, radiative

    Office of Scientific and Technical Information (OSTI)

    of Oklahoma Univ. of Oklahoma 79 ASTRONOMY AND ASTROPHYSICS Dark Energy, Type Ia supernovae, radiative transfer, Dark Energy, Type Ia supernovae, radiative transfer, The...

  5. Constraining Cosmic Evolution of Type Ia Supernovae (Journal...

    Office of Scientific and Technical Information (OSTI)

    Constraining Cosmic Evolution of Type Ia Supernovae Citation Details In-Document Search Title: Constraining Cosmic Evolution of Type Ia Supernovae We present the first large-scale...

  6. Giant persistent photoconductivity in BaTiO{sub 3}/TiO{sub 2} heterostructures

    SciTech Connect (OSTI)

    Plodinec, Milivoj; anti?, Ana; Gajovi?, Andreja; Zavanik, Janez; ?eh, Miran

    2014-10-13

    The persistent photoconductivity (PPC) effect in nanotube arrays of barium titanate and TiO{sub 2} (BTO/TiO{sub 2}NT) was studied at room temperature under daylight illumination. The BTO/TiO{sub 2}NT heterostructures exhibited a giant PPC effect that was six orders of magnitude higher than the dark conductivity, followed by a slow relaxation for 3 h. The PPC in this material was explained by the existence of defects at the surfaces and the interfaces of the investigated heterostructures. The sample was prepared using a two-step synthesis: the anodization of a Ti-foil and a subsequent hydrothermal synthesis. The structural and electrical characteristics were studied by micro-Raman spectroscopy, field-emission-gun scanning electron microscopy, and impedance spectroscopy.

  7. Type Ia Supernovae Project at NERSC

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of star called a white dwarf. The majority of SN Ia explosions occur far away from our galaxy; yet, due to their enormous intrinsic brightness, outshining billions of stars, we can...

  8. IA Blog Archive | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    "always be five years away." For four key clean energy technologies, that clean energy future has already arrived. August 21, 2013 IA Blog Archive ActOnClimate: Secretary...

  9. Spore Coat Architecture of Clostridium novyi-NT spores

    SciTech Connect (OSTI)

    Plomp, M; McCafferey, J; Cheong, I; Huang, X; Bettegowda, C; Kinzler, K; Zhou, S; Vogelstein, B; Malkin, A

    2007-05-07

    Spores of the anaerobic bacterium Clostridium novyi-NT are able to germinate in and destroy hypoxic regions of tumors in experimental animals. Future progress in this area will benefit from a better understanding of the germination and outgrowth processes that are essential for the tumorilytic properties of these spores. Towards this end, we have used both transmission electron microscopy and atomic force microscopy to determine the structure of dormant as well as germinating spores. We found that the spores are surrounded by an amorphous layer intertwined with honeycomb parasporal layers. Moreover, the spore coat layers had apparently self-assembled and this assembly was likely to be governed by crystal growth principles. During germination and outgrowth, the honeycomb layers as well as the underlying spore coat and undercoat layers sequentially dissolved until the vegetative cell was released. In addition to their implications for understanding the biology of C. novyi-NT, these studies document the presence of proteinaceous growth spirals in a biological organism.

  10. Improved Distances to Type Ia Supernovae withMulticolor Light...

    Office of Scientific and Technical Information (OSTI)

    We present an updated version of the Multicolor Light Curve Shape method to measure distances to type Ia supernovae (SN Ia), incorporating new procedures for K-correction and ...

  11. Ideal bandpasses for type Ia supernova cosmology

    SciTech Connect (OSTI)

    Davis, Tamara M.; Schmidt, Brian P.; Kim, Alex G.

    2005-10-24

    To use type Ia supernovae as standard candles for cosmologywe need accurate broadband magnitudes. In practice the observed magnitudemay differ from the ideal magnitude-redshift relationship either throughintrinsic inhomogeneities in the type Ia supernova population or throughobservational error. Here we investigate how we can choose filterbandpasses to reduce the error caused by both these effects. We find thatbandpasses with large integral fluxes and sloping wings are best able tominimise several sources of observational error, and are also leastsensitive to intrinsic differences in type Ia supernovae. The mostimportant feature of a complete filter set for type Ia supernovacosmology is that each bandpass be a redshifted copy of the first. Wedesign practical sets of redshifted bandpasses that are matched totypical high resistivity CCD and HgCdTe infra-red detector sensitivities.These are designed to minimise systematic error in well observedsupernovae, final designs for specific missions should also considersignal-to-noise requirements and observing strategy. In addition wecalculate how accurately filters need to be calibrated in order toachieve the required photometric accuracy of future supernova cosmologyexperiments such as the SuperNova-Acceleration-Probe (SNAP), which is onepossible realisation of the Joint Dark-Energy mission (JDEM). We considerthe effect of possible periodic miscalibrations that may arise from theconstruction of an interference filter.

  12. A threat-based definition of IA- and IA-enabled products.

    SciTech Connect (OSTI)

    Shakamuri, Mayuri; Schaefer, Mark A.; Campbell, Philip LaRoche

    2010-07-01

    This paper proposes a definition of 'IA and IA-enabled products' based on threat, as opposed to 'security services' (i.e., 'confidentiality, authentication, integrity, access control or non-repudiation of data'), as provided by Department of Defense (DoD) Instruction 8500.2, 'Information Assurance (IA) Implementation.' The DoDI 8500.2 definition is too broad, making it difficult to distinguish products that need higher protection from those that do not. As a consequence the products that need higher protection do not receive it, increasing risk. The threat-based definition proposed in this paper solves those problems by focusing attention on threats, thereby moving beyond compliance to risk management. (DoDI 8500.2 provides the definitions and controls that form the basis for IA across the DoD.) Familiarity with 8500.2 is assumed.

  13. A threat-based definition of IA and IA-enabled products.

    SciTech Connect (OSTI)

    Shakamuri, Mayuri; Schaefer, Mark A.; Campbell, Philip LaRoche

    2010-09-01

    This paper proposes a definition of 'IA and IA-enabled products' based on threat, as opposed to 'security services' (i.e., 'confidentiality, authentication, integrity, access control or non-repudiation of data'), as provided by Department of Defense (DoD) Instruction 8500.2, 'Information Assurance (IA) Implementation.' The DoDI 8500.2 definition is too broad, making it difficult to distinguish products that need higher protection from those that do not. As a consequence the products that need higher protection do not receive it, increasing risk. The threat-based definition proposed in this paper solves those problems by focusing attention on threats, thereby moving beyond compliance to risk management. (DoDI 8500.2 provides the definitions and controls that form the basis for IA across the DoD.) Familiarity with 8500.2 is assumed.

  14. Best management practices and work plan for installation of and monitoring at temporary weirs and flumes at NT-3, NT-4, and NT-5 Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect (OSTI)

    1998-02-01

    This Best Management Practices (BMP) and Work Plan has been developed in order to maintain compliance with applicable regulatory requirements by documenting the practices that are required during the installation and maintenance of temporary weirs and flumes at the NT-3, NT-4, and NT-5 tributaries, subsequent collection of water discharge data, and removal of the weirs and flumes. The practices included in this BMP comply with the Clean Water Act and the intent of Sect. 70-8-104(b) of the Tennessee Code Annotated: Tennessee Wildlife Resources Commission Proclamation 94-16 to prevent the destruction of the habitat of state-listed wildlife species that are designated as {open_quotes}in need of management.{close_quotes}

  15. The Fifteenth International Conference on the Science and Application of Nanotubes (NT14)

    SciTech Connect (OSTI)

    cronin, stephen

    2015-01-06

    The Fifteenth International Conference on the Science and Application of Nanotubes (NT14) was held at the University of Southern California in Los Angeles, California on June 2-6, 2014. NT14 upheld the NT tradition of presenting the latest results in the science and applications of nanotubes and related materials in plenary sessions. Emphasis was given to convivial poster sessions and student participation. Over 225 participants attended the conference, including students, post-docs, faculty, and members from industry. A total of 45 talks were presented, as well as 157 posters.

  16. IA News Archive | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    News Archive IA News Archive RSS July 22, 2016 Energy Department Selects Argonne National Laboratory to Lead U.S. Consortium for New CERC Medium- and Heavy-Duty Truck Technical Track The New Consortium of University, Private Sector and National Laboratory Partners will Advance Collaboration between the U.S. and China on Truck Efficiency Technologies June 10, 2016 Energy Department Invests More than $10 Million in Efficient Lighting Research and Development New projects designed to save consumers

  17. DE-AI26-06NT42938 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    938 Gas Hydrates Research Database and Web Dissemination Channel DE-AI26-06NT42938 Last ... The U.S. Hydrate Database stores information on a relational Oracle based system with Web-...

  18. Type Ia Supernova Hubble Residuals and Host-Galaxy Properties...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Journal Article: Type Ia Supernova Hubble Residuals and ... as distinguished from previous works that use magnitude corrections as a ...

  19. CEPHEID CALIBRATIONS OF MODERN TYPE Ia SUPERNOVAE: IMPLICATIONS...

    Office of Scientific and Technical Information (OSTI)

    CEPHEID CALIBRATIONS OF MODERN TYPE Ia SUPERNOVAE: IMPLICATIONS FOR THE HUBBLE CONSTANT ... Country of Publication: United States Language: English Subject: 79 ASTROPHYSICS, ...

  20. Constraining Cosmic Evolution of Type Ia Supernovae

    SciTech Connect (OSTI)

    Foley, Ryan J.; Filippenko, Alexei V.; Aguilera, C.; Becker, A.C.; Blondin, S.; Challis, P.; Clocchiatti, A.; Covarrubias, R.; Davis, T.M.; Garnavich, P.M.; Jha, S.; Kirshner, R.P.; Krisciunas, K.; Leibundgut, B.; Li, W.; Matheson, T.; Miceli, A.; Miknaitis, G.; Pignata, G.; Rest, A.; Riess, A.G.; /UC, Berkeley, Astron. Dept. /Cerro-Tololo InterAmerican Obs. /Washington U., Seattle, Astron. Dept. /Harvard-Smithsonian Ctr. Astrophys. /Chile U., Catolica /Bohr Inst. /Notre Dame U. /KIPAC, Menlo Park /Texas A-M /European Southern Observ. /NOAO, Tucson /Fermilab /Chile U., Santiago /Harvard U., Phys. Dept. /Baltimore, Space Telescope Sci. /Johns Hopkins U. /Res. Sch. Astron. Astrophys., Weston Creek /Stockholm U. /Hawaii U. /Illinois U., Urbana, Astron. Dept.

    2008-02-13

    We present the first large-scale effort of creating composite spectra of high-redshift type Ia supernovae (SNe Ia) and comparing them to low-redshift counterparts. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe through a multiple-decade effort at Lick and Keck Observatories, and we have used 45 ultraviolet spectra obtained by HST/IUE. The low-redshift spectra act as a control sample when comparing to the ESSENCE spectra. In all instances, the ESSENCE and Lick composite spectra appear very similar. The addition of galaxy light to the Lick composite spectra allows a nearly perfect match of the overall spectral-energy distribution with the ESSENCE composite spectra, indicating that the high-redshift SNe are more contaminated with host-galaxy light than their low-redshift counterparts. This is caused by observing objects at all redshifts with similar slit widths, which corresponds to different projected distances. After correcting for the galaxy-light contamination, subtle differences in the spectra remain. We have estimated the systematic errors when using current spectral templates for K-corrections to be {approx}0.02 mag. The variance in the composite spectra give an estimate of the intrinsic variance in low-redshift maximum-light SN spectra of {approx}3% in the optical and growing toward the ultraviolet. The difference between the maximum-light low and high-redshift spectra constrain SN evolution between our samples to be < 10% in the rest-frame optical.

  1. Composite WO3/TiO2 nanostructures for high electrochromic activity

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Reyes-Gil, Karla R.; Stephens, Zachary D.; Stavila, Vitalie; Robinson, David B.

    2015-01-06

    A composite material consisting of TiO2 nanotubes (NT) with WO3 electrodeposited on its surface has been fabricated, detached from its Ti substrate, and attached to a fluorine-doped tin oxide (FTO) film on glass for application to electrochromic (EC) reactions. Several adhesion layers were tested, finding that a paste of TiO2 made from commercially available TiO2 nanoparticles creates an interface for the TiO2 NT film to attach to the FTO glass, which is conductive and does not cause solution-phase ions in an electrolyte to bind irreversibly with the material. The effect of NT length and WO3 concentration on the EC performancemore » were studied. As a result, the composite WO3/TiO2 nanostructures showed higher ion storage capacity, better stability, enhanced EC contrast, and longer memory time compared with the pure WO3 and TiO2 materials« less

  2. Search for surviving companions in type Ia supernova remnants

    SciTech Connect (OSTI)

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E. E-mail: pmricker@illinois.edu E-mail: taam@asiaa.sinica.edu.tw

    2014-09-01

    The nature of the progenitor systems of type Ia supernovae (SNe Ia) is still unclear. One way to distinguish between the single-degenerate scenario and double-degenerate scenario for their progenitors is to search for the surviving companions (SCs). Using a technique that couples the results from multi-dimensional hydrodynamics simulations with calculations of the structure and evolution of main-sequence- (MS-) and helium-rich SCs, the color and magnitude of MS- and helium-rich SCs are predicted as functions of time. The SC candidates in Galactic type Ia supernova remnants (Ia SNR) and nearby extragalactic Ia SNRs are discussed. We find that the maximum detectable distance of MS SCs (helium-rich SCs) is 0.6-4 Mpc (0.4-16 Mpc), if the apparent magnitude limit is 27 in the absence of extinction, suggesting that the Large and Small Magellanic Clouds and the Andromeda Galaxy are excellent environments in which to search for SCs. However, only five Ia SNRs have been searched for SCs, showing little support for the standard channels in the singe-degenerate scenario. To better understand the progenitors of SNe Ia, we encourage the search for SCs in other nearby Ia SNRs.

  3. THE ULTRAVIOLET BRIGHTEST TYPE Ia SUPERNOVA 2011de

    SciTech Connect (OSTI)

    Brown, Peter J., E-mail: pbrown@physics.tamu.edu [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843 (United States)

    2014-11-20

    We present and discuss the ultraviolet (UV)/optical photometric light curves and absolute magnitudes of the TypeIa supernova (SN Ia) 2011de from the Swift Ultraviolet/Optical Telescope. We find it to be the UV brightest SN Ia yet observedmore than a factor of 10 brighter than normal SNe Ia in the mid-ultraviolet. We find that the UV/optical brightness and broad light curve evolution can be modeled with additional flux from the shock of the ejecta hitting a relatively large red giant companion separated by 6 10{sup 13} cm. However, the post-maximum behavior of other UV-bright SNe Ia can also be modeled in a similar manner, including objects with UV spectroscopy or pre-maximum photometry which is inconsistent with this model. This suggests that similar UV luminosities can be intrinsic or caused by other forms of shock interaction. The high velocities reported for SN 2011de make it distinct from the UV-bright ''super-Chandrasekhar'' SNe Ia and the NUV-blue group of normal SNe Ia. SN 2011de is an extreme example of the UV variations in SNe Ia.

  4. DIVERSITY OF TYPE Ia SUPERNOVAE IMPRINTED IN CHEMICAL ABUNDANCES

    SciTech Connect (OSTI)

    Tsujimoto, Takuji [National Astronomical Observatory of Japan, Mitaka-shi, Tokyo 181-8588 (Japan); Shigeyama, Toshikazu, E-mail: taku.tsujimoto@nao.ac.jp [Research Center for the Early Universe, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-12-01

    A time delay of Type Ia supernova (SN Ia) explosions hinders the imprint of their nucleosynthesis on stellar abundances. However, some occasional cases give birth to stars that avoid enrichment of their chemical compositions by massive stars and thereby exhibit an SN-Ia-like elemental feature including a very low [Mg/Fe] ( Almost-Equal-To - 1). We highlight the elemental feature of Fe-group elements for two low-Mg/Fe objects detected in nearby galaxies, and propose the presence of a class of SNe Ia that yield the low abundance ratios of [Cr, Mn, Ni/Fe]. Our novel models of chemical evolution reveal that our proposed class of SNe Ia (slow SNe Ia) is associated with ones exploding on a long timescale after their stellar birth and give a significant impact on the chemical enrichment in the Large Magellanic Cloud (LMC). In the Galaxy, on the other hand, this effect is unseen due to the overwhelming enrichment by the major class of SNe Ia that explode promptly (prompt SNe Ia) and eject a large amount of Fe-group elements. This nicely explains the different [Cr, Mn, Ni/Fe] features between the two galaxies as well as the puzzling feature seen in the LMC stars exhibiting very low Ca but normal Mg abundances. Furthermore, the corresponding channel of slow SN Ia is exemplified by performing detailed nucleosynthesis calculations in the scheme of SNe Ia resulting from a 0.8 + 0.6 M{sub Sun} white dwarf merger.

  5. DOE - Office of Legacy Management -- Bendix Aviation Corp Pioneer Div - IA

    Office of Legacy Management (LM)

    05 Corp Pioneer Div - IA 05 FUSRAP Considered Sites Site: BENDIX AVIATION CORP., PIONEER DIV. (IA.05 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: Pioneer Division, Bendix Aviation Corporation Bendix Aviation Corporation Bendix Pioneer Division IA.05-1 IA.05-2 IA.05-3 Location: Davenport , Iowa IA.05-1 Evaluation Year: 1990 IA.05-2 IA.05-4 Site Operations: Conducted studies to investigate the feasibility of using sonic cleaning equipment to

  6. LAX XXlCfl jX?iK, Idd+?KYLViG?IA

    Office of Legacy Management (LM)

    f , : I~&l, samtier cipwati8Aa CffUm - . Jiux.lCJ d,# 1754 - - _- - .- t :; . Jesse e. ahizmn*~*ter -2.' -------- - _ &tV' hi@A l f izau Bkteriala ;' . . 1 -7 I _' i' . Fpr&G& r&Q Q,&& fu &fI& L;&& -l&d 2;,i' iI,;/Qi' rIGN CQ&GgJy p;E& p;~p>gyf LAX XXlCfl jX?iK, Idd+?KYLViG?IA i-icfer~~o is &o ta yaw rwarandu3;: l P iimwmbec L?, 1953, reque&in~ a d&q.&ti of khority tA A&sister prog= for th+zz developmrrrl,

  7. Composite WO3/TiO2 nanostructures for high electrochromic activity

    SciTech Connect (OSTI)

    Reyes-Gil, Karla R.; Stephens, Zachary D.; Stavila, Vitalie; Robinson, David B.

    2015-01-06

    A composite material consisting of TiO2 nanotubes (NT) with WO3 electrodeposited on its surface has been fabricated, detached from its Ti substrate, and attached to a fluorine-doped tin oxide (FTO) film on glass for application to electrochromic (EC) reactions. Several adhesion layers were tested, finding that a paste of TiO2 made from commercially available TiO2 nanoparticles creates an interface for the TiO2 NT film to attach to the FTO glass, which is conductive and does not cause solution-phase ions in an electrolyte to bind irreversibly with the material. The effect of NT length and WO3 concentration on the EC performance were studied. As a result, the composite WO3/TiO2 nanostructures showed higher ion storage capacity, better stability, enhanced EC contrast, and longer memory time compared with the pure WO3 and TiO2 materials

  8. DOE - Office of Legacy Management -- Iowa Army Ammunition Plant - IA 02

    Office of Legacy Management (LM)

    Army Ammunition Plant - IA 02 FUSRAP Considered Sites Iowa Army Ammunition Plant, IA Alternate Name(s): Burlington Ordnance Plant Iowa Ordnance Plant Silas Mason Company IA.02-3 Location: Located in Township 70 North, Range 3 West, Section 32, 5th Principal Meridian, Des Moines County, Burlington, Iowa IA.02-1 IA.02-5 Historical Operations: Assembled nuclear weapons, primarily high explosive components and conducted explosives testing using the high explosive components and depleted uranium. AEC

  9. DE-AI26-06NT42878 - Alaminos Canyon Task | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Alaminos Canyon Task Geochemical Evaluation of Deep Sediment Hydrate Deposits in Alaminos Canyon, Block 818, Texas-Louisiana Shelf DE-AI26-06NT42878 - Alaminos Canyon Task Project Goal This project was intended to test the usefulness of shallow geochemistry and heat flow data acquisition as an aid in the delineation of deeper, concentrated gas hydrate accumulations. NRL scientists conducted geochemical and heat flow surveys of selected sites in Alaminos Canyon Block 818, to support 1) DOE/

  10. DE-AI26-06NT42878 - New Zealand Task | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    New Zealand Task Gas Hydrate Research in Deep Sea Sediments - New Zealand Task DE-AI26-06NT42878 Project Goal The objective of this research is to determine the extent and dynamics of gas hydrate deposits and their relation to areas of focused fluid flux at and beneath the seafloor. Specific objectives include: a). Refine geophysical, geochemical and microbiological technologies for prospecting hydrate distribution and content; b). Contribute to establishing high-priority geographical regions of

  11. DE-AI26-06NT42878 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Gas Hydrate Research in Deep Sea Sediments - Chatham Rise, New Zealand Task Last Reviewed 5/13/2014 DE-AI26-06NT42878 Goal The goal of the Interagency Agreement between the National Energy Technology Laboratory and the Naval Research Laboratory is to conduct research to enhance understanding of the extent and dynamics of gas hydrate deposits and their relation to areas of focused fluid flux at and beneath the seafloor. Performer Marine Biogeochemistry Section, Naval Research Laboratory,

  12. DE-AM26-05NT42653 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Conceptual Engineering/Socioeconomic Impact Study-Alaska Spur Pipeline DE-AM26-05NT42653 Goal The goal of this project is to provide current information pertaining to the potential construction of a primarily buried spur pipeline that would bring gas from a proposed Alaska North Slope (ANS) gas line to South Central and Interior Alaska. The study is intended to provide comparative information for each of two currently proposed spur pipeline routes. Performers ASRC Constructors, Inc. Michael

  13. DE-FC26-00NT40916 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fundamentals of Natural Gas and Species Flows from Hydrate Dissociation - Applications to Safety Problems DE-FC26-00NT40916 Last Reviewed 02/05/2010 Project Goal Develop models to help determine the potential for sea floor and wellbore instability during drilling. Background There currently are no models that can address all of the characteristics of natural gas hydrates in sediments. The proposed effort was to develop a method to utilize the unique characteristics of hydrates for future

  14. DE-FC26-00NT40921 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Three-Dimensional Structure and Physical Properties of Methane Hydrate Deposit at Blake Ridge Bathymetric location map of the Blake Ridge study area Bathymetric location map of the Blake Ridge study area DE-FC26-00NT40921 Last Reviewed 02/05/2010 Goal Determine the linkage between hydrate concentration and seismic characteristics in subsea sediments. Performer University of Wyoming, Dept. of Geology and Geophysics - project management and research products Location Laramie, Wyoming 82071

  15. DE-FC26-01NT41158 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Development of an Environmentally Benign Microbial Inhibitor to Control Internal Pipeline Corrosion DE-FC26-01NT41158 Goal: The goal of this project is to help maintain the integrity of the United States natural gas infrastructure. Modified natural gas pipeline test cell Background: Corrosion is a leading cause for pipe failure, and is a main component of the operating and maintenance costs of gas industry pipelines. Quantifying the cost of corrosion generally in the gas industry, and more

  16. DE-FC26-01NT41162 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Improvement to Compressor Engine Reliability through Retrofit Micro-Pilot Ignition System DE-FC26-01NT41162 Goal: The goal of this project is to develop a highly reliable micro-pilot ignition system that can be retrofitted to older, 2-stroke, natural gas compressor engines now used throughout the nation's pipeline network, to enhance operational integrity, increase fuel efficiency and reduce emissions from these machines. Background: In total, the U.S. pipeline industry has approximately 8,000

  17. DE-FC26-01NT41163 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Increased Flexibility of Turbo-Compressors in Natural Gas Transmission through Direct Surge Control DE-FC26-01NT41163 Goal: The goal of this project is to help to improve and optimize the nation's natural gas transmission infrastructure through development of a new method to avoid surge of pipeline compressors. This method will safely expand the range of compressor operations, while minimizing wasteful recycle flow at the low end of the operating envelope, bringing about reductions in wasted

  18. DE-FC26-02NT41324 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Acoustic Detecting and Locating Gas Pipeline Infringement DE-FC26-02NT41324 Goal: The objective of this project is to develop a centralized and automated acoustic monitoring system to detect leaks in, and infringements on, high-pressure natural gas pipelines. This system will detect the unique sound waves and vibrations that are generated when a pipeline break releases gas due to landslides, excavations, demolitions, or other sudden disturbances. The system will be designed to monitor background

  19. DE-FC26-02NT41328 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Support of Gulf of Mexico Hydrate Research Consortium: Activities to Support Establishment of Sea Floor Monitoring Station DE-FC26-02NT41328 Project Goal Determine the potential impacts of gas hydrate instability in terms of the release of methane into seafloor sediments, the ocean and the atmosphere. Performers University of California, San Diego (Scripps Institution of Oceanography) - manage geochemical, hydrological and sedimentological investigations Texas A&M University - manage field

  20. DE-FC26-02NT41646 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Technologies to Enhance Operation of the Existing Natural Gas Compression Infrastructure DE-FC26-02NT41646 The goal is to improve operation of integral engine/compressors by reducing fuel consumption, increasing capacity, and enhancing mechanical integrity, leading to increased reliability of the nation's natural gas transmission infrastructure. Collage of 4 photos from Duke Energy Station showing Clark HBA Units HBA Units at Duke Energy Station Background: This three-year project employed

  1. DE-FC26-03NT41858 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Use of Pressure-Activated Sealant Technology to Cure Pipeline Leaks DE-FC26-03NT41858 Goal: The goal is to help maintain the nation's natural gas transmission infrastructure through development of a new, efficient, cost-effective method for internally sealing natural gas pipeline leaks through the application of differential pressure-activated sealants. Background: Seal-Tite LLC provides engineered sealing solutions utilizing a proprietary pressure activated sealant technology. This technology

  2. DE-FC26-03NT41859 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Advanced Compressor Engine Controls to Enhance Operation Reliability and Integrity DE-FC26-03NT41859 Goal: The goal of this project is to develop, evaluate, and demonstrate advanced, closed-loop NOx emissions controls for two-stroke integral gas compressor engines to enhance the operation, reliability, and integrity of the natural gas transmission system through development of advanced compressor technologies. Background: The gas transmission industry operates over 4,000 integral engine

  3. DE-FC26-03NT41881 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Innovative Sensors for Pipeline Crawlers to Assess Pipeline Defects and Conditions DE-FC26-03NT41881 Goal: The goal of this project is to develop electromagnetic sensors (based on eddy current technology) that can be integrated with a robotic platform (crawler) to conduct internal natural gas pipeline inspections. Combinations of sensor types will be used to assess a wide range of pipeline conditions, including corrosion (pitting, localized, and extended), mechanical damage, cracking, and seam

  4. DE-FC26-04NT42266 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Delivery Reliability for Natural Gas - Inspection Technologies DE-FC26-04NT42266 Goal: The objective of this project is to develop, construct, integrate, and test/demonstrate an accurate and dependable in-line pipeline inspection tool for natural gas transmission and distribution pipelines (four to eight inches in diameter). The inspection tool will consist of an advanced sensor, based on eddy current technology, capable of detecting pipeline defects and a semi-autonomous robotic platform (for

  5. DE-FC26-04NT42267 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Remote Detection of Internal Pipeline Corrosion Using Fluidized Sensors DE-FC26-04NT42267 Goal: The goal of the project is to develop technology that will enable remote interrogation of the internal corrosion of pipelines. Non-line-of-sight pipeline wireless data transmission test setup Background: Proposed sensor concept According to the Department of Transportation Office of Pipeline Safety (OPS), internal corrosion caused about 15 percent of all gas transmission pipeline reportable incidents

  6. DE-FC26-04NT42268 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    High-Altitude, Aerial Natural Gas Leak Detection System DE-FC26-04NT42268 Goal The goal of this project is to develop a Remote Methane Leak Detector (RMLD) system for standoff sensing, from high altitudes, of natural gas distribution and transmission pipeline leaks. Performers Physical Sciences, Inc. (PSI) - Andover, MA Heath Consultants, Inc. - Houston, TX Results Project researchers have: Completed and submitted the project Research Management Plan. Completed and submitted the Technology

  7. DE-FC26-04NT42269 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Advanced Reciprocating Compression Technologies (ARCT) DE-FC26-04NT42269 Goal: The goal of the Advanced Reciprocating Compression Technology (ARCT) program is to create the next generation of reciprocating compressor technology to enhance the flexibility, efficiency, reliability, and integrity of pipeline operations. The suite of technologies developed by this program will substantially improve the current infrastructure by offering increased capabilities to enhance pipeline throughput capacity

  8. DE-FC26-06NT42959 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Electrical Resistivity Investigation of Gas Hydrate Distribution in Mississippi Canyon Block 118, Gulf of Mexico Last Reviewed 6/14/2013 DE-FC26-06NT42959 Goal The goal of this project is to evaluate the direct-current electrical resistivity (DCR) method for remotely detecting and characterizing the concentration of gas hydrates in the deep marine environment. This will be accomplished by adapting existing DCR instrumentation for use on the sea floor in the deep marine environment and testing

  9. DE-FC26-06NT42962-P1 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    P1 Phase 1 - Characterization and Qualification of the Methane Hydrate Resource Potential Associated with the Barrow Gas Fields DE-FC26-06NT42962 Project Goal The goal of this project is to characterize and quantify the postulated gas hydrate resource associated with the Barrow Gas Fields - three producing fields located in a permafrost region near Barrow, the North Slope's biggest population center and economic hub. Map of the North Slope Borough showing the location of its eight major

  10. DE-FC26-06NT42963 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3 Methane Recovery from Hydrate-bearing Sediments DE-FC26-06NT42963 Last Reviewed 11/30/2011 Project Goal The goal of this project is to develop observational and experimental data that can provide a better understanding of the basic mechanisms at work in a methane hydrate reservoir that is under production. To this end, a thorough physical understanding of underlying phenomena associated with methane hydrate production will be acquired through unique, multi-scale experiments and associated

  11. {alpha}-particle optical potentials for nuclear astrophysics (NA) and nuclear technology (NT)

    SciTech Connect (OSTI)

    Avrigeanu, V.; Avrigeanu, M.

    2012-11-20

    The high precision of recent measurements for low-energy {alpha}-particle elastic-scattering as well as induced-reaction data makes possible the understanding of actual limits and possible improvement of the global optical model potentials parameters. Involvement of recent optical potentials for reliable description of both the elastic scattering and emission of {alpha}-particles, of equal interest for nuclear astrophysics (NA) and nuclear technology (NT) for fusion devices, is discussed in the present work.

  12. Transparent TiO2 nanotube array photoelectrodes prepared via two-step anodization

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kim, Jin Young; Zhu, Kai; Neale, Nathan R.; Frank, Arthur J.

    2014-04-04

    Two-step anodization of transparent TiO2 nanotube arrays has been demonstrated with aid of a Nb-doped TiO2 buffer layer deposited between the Ti layer and TCO substrate. Enhanced physical adhesion and electrochemical stability provided by the buffer layer has been found to be important for successful implementation of the two-step anodization process. As a result, with the proposed approach, the morphology and thickness of NT arrays could be controlled very precisely, which in turn, influenced their optical and photoelectrochemical properties.

  13. DE-AI26-06NT42878 - Bottom Source Task | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Bottom Source Task Gas Hydrate Research in Deep Sea Sediments DE-AI26-06NT42878 - Bottom Source Task Last Reviewed 11/7/2011 Project Goal The objective of this project is to develop and test a bottom-mounted seismic source for mapping gas hydrates in marine environments. The Naval Research Laboratory (NRL) will modify their existing Helmholtz resonator seismic source, which generates both compressional and shear waves, and develop a system for mounting it onto the seafloor. The resulting

  14. DE-FC26-01NT41329 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    In Situ Sampling and Characterization of Naturally Occurring Methane Hydrate Using the D/V JOIDES Resolution Last Reviewed 02/05/2010 DE-FC26-01NT41329 photo of a man showing the pressure core sampler on the deck of JOIDES Resolution Pressure core sampler on deck courtesy Texas A&M University Project Goal The goal of the project was to characterize hydrate accumulation at Hydrate Ridge (offshore Oregon) and improve the ability to use geophysical and subsurface logging to identify hydrates. A

  15. DE-FC26-01NT41330 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The National Methane Hydrates R&D Program Gulf of Mexico Gas Hydrates Joint Industry Project (JIP) Characterizing Natural Gas Hydrates in the Deep Water Gulf of Mexico - Applications for Safe Exploration and Production Last Reviewed 9/19/2014 DE-FC26-01NT41330 Goal: The goal of this project is to develop technology and collect data to assist in the characterization of naturally occurring gas hydrates in the deep water Gulf of Mexico (GoM). The intent of the project is to better understand

  16. DE-FC26-01NT41332 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Alaska North Slope Gas Hydrate Reservoir Characterization Last Reviewed 12/10/2014 DE-FC26-01NT41332 Goal The goal of this project is to characterize the large in-place methane hydrate resource on the Alaska North Slope (ANS) and to conduct field and lab studies to determine the potential for methane, produced from hydrate, to become a viable part of the overall energy supply. Performers BP Exploration Alaska, Inc. - providing access to data and selected field areas as well as project

  17. DE-FC26-02NT41316 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sealing Large Diameter Cast Iron Pipe Joints under Live Conditions DE-FC26-02NT41316 Goal: The project will develop a new technology for the in-line repair of natural gas pipelines. The objective of this project is to design, test, and commercialize a robotic system capable of sealing multiple cast iron bell and spigot joints from a single pipe entry point. The system will affect repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and attaching a

  18. DE-FC26-02NT41318 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Differential Soil Impedance Obstacle Detection DE-FC26-02NT41318 Goal: The goal of this project is to design, fabricate, and test a prototype sensor system for detecting obstacles in front of, or nearby the head of a horizontal directional drilling (HDD) rig. The sensor will be designed to be sensitive to metallic, plastic, or ceramic obstacles embedded in the soil. Background: The use of guided directional drilling for the installation of gas services and mains by the natural gas industry is

  19. DE-FC26-02NT41604 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Pipelines as Networked Communication Links DE-FC26-02NT41604 Goal: The goal of this project is to investigate the use of a natural gas pipeline as a means of transmitting signals by either of two methods: as a waveguide for microwaves or commercial wireless modems, or by directly introducing a signal into the pipe (treating the pipe as a leaky feeder or a multi-ground neutral). Using the pipeline as a carrier for communication signals would facilitate the use of pipeline maintenance and leak

  20. DE-FC26-02NT41632 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection DE-FC26-02NT41632 Goal: The goal is to help maintain and enhance the integrity of the nation's natural gas infrastructure. Background: The most common type of leak detection equipment used by the natural gas industry is the Flame Ionization Detector (FID). The FID is a simple, easy to use, portable instrument with a 5 to 10 ppm level of sensitivity. A major limitation of FIDs for natural gas leak

  1. DE-FC26-02NT41643 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    IEMDC - Totally Enclosed In-Line Electric Motor Driven Compressor DE-FC26-02NT41643 Goal: The goal of this project is to develop a gas compressor that can be installed directly in a pipeline, utilizing a variable speed induction motor with magnetic bearings. The project will advance the direct-coupled, seal-less, in-line electric motor driven compressor (IEMDC) to the stage where detailed manufacturing drawings can commence. Background: A recognized need exists within the gas transmission

  2. DE-FC26-03NT41877 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Testing of an Advanced Airborne Natural Gas Leak Detection System DE-FC26-03NT41877 Goal: The goal is to improve the method by which the nation's natural gas pipelines are monitored for leaks. This project will flight test a high-sensitivity, broad-coverage, airborne, natural gas leak detection system developed by ITT Industries (formerly Eastman Kodak Company). The ITT airborne system can be used to quickly and efficiently locate and detect and locate concentrations of natural gas associated

  3. DE-FC26-03NT41879 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Development of a Remote External Repair Tool for Damaged or Defective PE Pipe DE-FC26-03NT41879 Goal: The goal of this project is to develop a remote repair tool that utilizes unique chemical and mechanical processes to apply a permanent external repair patch to damaged or defective buried polyethylene (PE) natural gas pipe. This work will demonstrate the functionality and test the performance of a fully engineered prototype repair tool in laboratory and field tests. Test Tool Conceptual Design

  4. DE-FC26-05NT42664 - ESD05-036 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    4 - ESD05-036 Geomechanical Performance of Hydrate-Bearing Sediments in Offshore Environments DE-FC26-05NT42664 / ESD05-036 Last Reviewed 12/09/2008 Project Goal The goal of this project is to develop the necessary knowledge base and quantitative predictive capability for modeling the geomechanical performance of hydrate-bearing sediments (HBS) in oceanic environments, in particular to determine the envelope of hydrate stability under conditions typical of those related to the construction and

  5. DE-FC26-05NT42665 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    5 Gas Hydrate Instability in the Southeastern Bering Sea DE-FC26-05NT42665 Project Goal The objective of this study was to test the hypothesis that gas hydrate dissociation in marine sediments was associated with and may actually have driven millennial scale climate change during Marine Isotope Stage (MIS) 3 and during other time periods in the late Quaternary. An investigation of the nature of deposition and alteration of the methane hydrate in cores from the Umnak Plateau in the southeastern

  6. DE-FC26-06NT43067 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3067 Mechanisms Leading to Co-existence of Gas and Hydrate in Ocean Sediments DE-FC26-06NT43067 Last Reviewed 5/15/2012 Project Goal The goal of this project is to quantitatively describe and understand the manner in which methane is transported within the Hydrate Stability Zone (HSZ) and consequently, the growth behavior of methane hydrates at both the grain scale and bed scale. Schematic conceptual diagram showing fault pathways for thermal gas to supply hydrate accumulations and free gas

  7. DFPARThIl!NT OF ENERGY EERE PROJECT MANAGEMENT CENTER NEPA DETERlIfiNATION

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    s DFPARThIl!NT OF ENERGY EERE PROJECT MANAGEMENT CENTER NEPA DETERlIfiNATION Page 1 of3 RECIPIENT :State of Hawaii DBEOT STATE : HI PROJECf TITLE: Loan Loss Reserve Funding Opportunity Announc~ment Number DE-FOA-0000052 Procurement Inslrument Number DE-EEOOOO216 NEPA Control Number em Number GF0-0000216-001 GO Based on my review ofthe informalion concerning the proposed aClion, as NEPA Compliance Officer (authorized under DOE Order 451.1A), I have made the following determination: ex, EA, EIS

  8. A STUDY OF CARBON FEATURES IN TYPE Ia SUPERNOVA SPECTRA (Journal...

    Office of Scientific and Technical Information (OSTI)

    A STUDY OF CARBON FEATURES IN TYPE Ia SUPERNOVA SPECTRA Citation Details In-Document Search Title: A STUDY OF CARBON FEATURES IN TYPE Ia SUPERNOVA SPECTRA One of the major ...

  9. Composite WO3/TiO2 nanostructures for high electrochromic activity.

    SciTech Connect (OSTI)

    Reyes, Karla Rosa; Stephens, Zachary Dan.; Robinson, David B.

    2013-05-01

    A composite material consisting of TiO2 nanotubes (NTs) with WO3 electrodeposited homogeneously on its surface has been fabricated, detached from its substrate, and attached to a fluorine-doped tin oxide film on glass for application to electrochromic (EC) reactions. A paste of TiO2 made from commercially available TiO2 nanoparticles creates an interface for the TiO2 NT film to attach to the FTO glass, which is conductive and does not cause solution-phase ions in an electrolyte to bind irreversibly with the material. The effect of NT length on the current density and the EC contrast of the material were studied. The EC redox reaction seen in this material is diffusion- limited, having relatively fast reaction rates at the electrode surface. The composite WO3/TiO2 nanostructures showed higher ion storage capacity, better stability, enhanced EC contrast and longer memory time compared with the pure WO3 and TiO2.

  10. An Analysis of Department of Defense Instruction 8500.2 'Information Assurance (IA) Implementation.'

    SciTech Connect (OSTI)

    Campbell, Philip LaRoche

    2012-01-01

    The Department of Defense (DoD) provides its standard for information assurance in its Instruction 8500.2, dated February 6, 2003. This Instruction lists 157 'IA Controls' for nine 'baseline IA levels.' Aside from distinguishing IA Controls that call for elevated levels of 'robustness' and grouping the IA Controls into eight 'subject areas' 8500.2 does not examine the nature of this set of controls, determining, for example, which controls do not vary in robustness, how this set of controls compares with other such sets, or even which controls are required for all nine baseline IA levels. This report analyzes (1) the IA Controls, (2) the subject areas, and (3) the Baseline IA levels. For example, this report notes that there are only 109 core IA Controls (which this report refers to as 'ICGs'), that 43 of these core IA Controls apply without variation to all nine baseline IA levels and that an additional 31 apply with variations. This report maps the IA Controls of 8500.2 to the controls in NIST 800-53 and ITGI's CoBIT. The result of this analysis and mapping, as shown in this report, serves as a companion to 8500.2. (An electronic spreadsheet accompanies this report.)

  11. Type Ia Supernova Spectral Line Ratios as LuminosityIndicators

    SciTech Connect (OSTI)

    Bongard, Sebastien; Baron, E.; Smadja, G.; Branch, David; Hauschildt, Peter H.

    2005-12-07

    Type Ia supernovae have played a crucial role in thediscovery of the dark energy, via the measurement of their light curvesand the determination of the peak brightness via fitting templates to theobserved lightcurve shape. Two spectroscopic indicators are also known tobe well correlated with peak luminosity. Since the spectroscopicluminosity indicators are obtained directly from observed spectra, theywill have different systematic errors than do measurements usingphotometry. Additionally, these spectroscopic indicators may be usefulfor studies of effects of evolution or age of the SNe~;Ia progenitorpopulation. We present several new variants of such spectroscopicindicators which are easy to automate and which minimize the effects ofnoise. We show that these spectroscopic indicators can be measured byproposed JDEM missions such as snap and JEDI.

  12. Next-Generation Petascale Simulations of Type Ia Supernovae | Argonne

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Leadership Computing Facility deflagration to detonation transition model Deflagration to detonation transition model. Min lOng, Dan van Rossum, Sean Couch, George Jordan, Brad Gallagher, Don Lamb, University of Chicago; Michael E. Papka, Argonne National Laboratory/University of Chicago Next-Generation Petascale Simulations of Type Ia Supernovae PI Name: Don Lamb PI Email: lamb@oddjob.uchicago.edu Institution: The University of Chicago Allocation Program: INCITE Allocation Hours at ALCF:

  13. Microsoft PowerPoint - IEEE IAS PES 102313.pptx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    DOE's ARRA Smart Grid Program Steve Bossart, Senior Energy Analyst IEEE IAS/PES Pittsburgh Section October 23, 2013 # Topics * OE ARRA Smart Grid Program * OE ARRA Smart Grid Progress * Results and Case Studies * Life After ARRA Smart Grid # DOE OE ARRA Smart Grid Program # American Recovery and Reinvestment Act ($4.5B) * Smart Grid Investment Grants (99 projects) - $3.4 billion Federal; $4.7 billion private sector - > 800 PMUs covering almost 100% of transmission - ~ 8000 distribution

  14. Power-law cosmology, SN Ia, and BAO

    SciTech Connect (OSTI)

    Dolgov, Aleksander; Halenka, Vitali; Tkachev, Igor E-mail: vithal@umich.edu

    2014-10-01

    We revise observational constraints on the class of models of modified gravity which at low redshifts lead to a power-law cosmology. To this end we use available public data on Supernova Ia and on baryon acoustic oscillations. We show that the expansion regime a(t)?t{sup ?} with ? close to 3/2 in a spatially flat universe is a good fit to these data.

  15. Signatures of a companion star in type Ia supernovae

    SciTech Connect (OSTI)

    Maeda, Keiichi; Kutsuna, Masamichi; Shigeyama, Toshikazu

    2014-10-10

    Although type Ia supernovae (SNe Ia) have been used as precise cosmological distance indicators, their progenitor systems remain unresolved. One of the key questions is whether there is a nondegenerate companion star at the time of a thermonuclear explosion of a white dwarf. In this paper, we investigate whether an interaction between the SN ejecta and the companion star may result in observable footprints around the maximum brightness and thereafter, by performing multidimensional radiation transfer simulations based on hydrodynamic simulations of the interaction. We find that such systems result in variations in various observational characteristics due to different viewing directions, and the predicted behaviors (redder and fainter for the companion direction) are the opposite of what were suggested by the previous study. The variations are generally modest and within observed scatters. However, the model predicts trends between some observables different from those observationally derived, so a large sample of SNe Ia with small calibration errors may be used to constrain the existence of such a companion star. The variations in different colors in optical band passes can be mimicked by external extinctions, so such an effect could be a source of scatter in the peak luminosity and derived distance. After the peak, hydrogen-rich materials expelled from the companion will manifest themselves in hydrogen lines, but Hα is extremely difficult to identify. Alternatively, we find that P{sub β} in postmaximum near-infrared spectra can potentially provide a powerful diagnostic.

  16. Type Ia Supernova Hubble Residuals and Host-Galaxy Properties (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Journal Article: Type Ia Supernova Hubble Residuals and Host-Galaxy Properties Citation Details In-Document Search Title: Type Ia Supernova Hubble Residuals and Host-Galaxy Properties Kim et al. (2013) [K13] introduced a new methodology for determining peak- brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized

  17. THE HYBRID CONe WD + He STAR SCENARIO FOR THE PROGENITORS OF TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Wang, B.; Meng, X.; Liu, D.-D.; Han, Z.; Liu, Z.-W.

    2014-10-20

    Hybrid CONe white dwarfs (WDs) have been suggested to be possible progenitors of type Ia supernovae (SNe Ia). In this Letter, we systematically studied the hybrid CONe WD + He star scenario for the progenitors of SNe Ia, in which a hybrid CONe WD increases its mass to the Chandrasekhar mass limit by accreting He-rich material from a non-degenerate He star. We obtained the SN Ia birthrates and delay times for this scenario using to a series of detailed binary population synthesis simulations. The SN Ia birthrates for this scenario are ∼0.033-0.539 × 10{sup –3} yr{sup –1}, which roughly accounts for 1%-18% of all SNe Ia. The estimated delay times are ∼28 Myr-178 Myr, which makes these the youngest SNe Ia predicted by any progenitor model so far. We suggest that SNe Ia from this scenario may provide an alternative explanation for type Iax SNe. We also presented some properties of the donors at the point when the WDs reach the Chandrasekhar mass. These properties may be a good starting point for investigating the surviving companions of SNe Ia and for constraining the progenitor scenario studied in this work.

  18. Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light

    Office of Scientific and Technical Information (OSTI)

    Curves (Journal Article) | SciTech Connect Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves Citation Details In-Document Search Title: Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves We combine the CfA3 supernovae Type Ia (SN Ia) sample with samples from the literature to calculate improved constraints on the dark energy equation of state parameter, w. The CfA3 sample is added to the Union set of Kowalski et al. to form the

  19. The Carnegie Supernova Project: Intrinsic colors of type Ia supernovae

    SciTech Connect (OSTI)

    Burns, Christopher R.; Persson, S. E.; Freedman, Wendy L.; Madore, Barry F. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Stritzinger, Maximilian; Contreras, Carlos [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Phillips, M. M.; Hsiao, E. Y.; Boldt, Luis; Campillay, Abdo; Castelln, Sergio; Morrell, Nidia; Salgado, Francisco [Carnegie Institution of Washington, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Folatelli, Gaston [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, the University of Tokyo, 277-8583 Kashiwa (Japan); Suntzeff, Nicholas B. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, Department of Physics and Astronomy, College Station, TX 77843 (United States)

    2014-07-01

    We present an updated analysis of the intrinsic colors of Type Ia supernova (SNe Ia) using the latest data release of the Carnegie Supernova Project. We introduce a new light-curve parameter very similar to stretch that is better suited for fast-declining events, and find that these peculiar types can be seen as extensions to the population of 'normal' SNe Ia. With a larger number of objects, an updated fit to the Lira relation is presented along with evidence for a dependence on the late-time slope of the B V light-curves with stretch and color. Using the full wavelength range from u to H band, we place constraints on the reddening law for the sample as a whole and also for individual events/hosts based solely on the observed colors. The photometric data continue to favor low values of R{sub V} , though with large variations from event to event, indicating an intrinsic distribution. We confirm the findings of other groups that there appears to be a correlation between the derived reddening law, R{sub V} , and the color excess, E(B V), such that larger E(B V) tends to favor lower R{sub V} . The intrinsic u-band colors show a relatively large scatter that cannot be explained by variations in R{sub V} or by the Goobar power-law for circumstellar dust, but rather is correlated with spectroscopic features of the supernova and is therefore likely due to metallicity effects.

  20. Grouping normal type Ia supernovae by UV to optical color differences

    SciTech Connect (OSTI)

    Milne, Peter A.; Brown, Peter J.; Roming, Peter W. A.; Bufano, Filomena; Gehrels, Neil

    2013-12-10

    Observations of many Type Ia supernovae (SNe Ia) for multiple epochs per object with the Swift Ultraviolet Optical Telescope instrument have revealed that there exists order to the differences in the UV-optical colors of optically normal supernovae (SNe). We examine UV-optical color curves for 23 SNe Ia, dividing the SNe into four groups, and find that roughly one-third of 'NUV-blue' SNe Ia have bluer UV-optical colors than the larger 'NUV-red' group. Two minor groups are recognized, 'MUV-blue' and 'irregular' SNe Ia. While we conclude that the latter group is a subset of the NUV-red group, containing the SNe with the broadest optical peaks, we conclude that the 'MUV-blue' group is a distinct group. Separating into the groups and accounting for the time evolution of the UV-optical colors lowers the scatter in two NUV-optical colors (e.g., u v and uvw1 v) to the level of the scatter in b v. This finding is promising for extending the cosmological utilization of SNe Ia into the NUV. We generate spectrophotometry of 33 SNe Ia and determine the correct grouping for each. We argue that there is a fundamental spectral difference in the 2900-3500 wavelength range, a region suggested to be dominated by absorption from iron-peak elements. The NUV-blue SNe Ia feature less absorption than the NUV-red SNe Ia. We show that all NUV-blue SNe Ia in this sample also show evidence of unburned carbon in optical spectra, whereas only one NUV-red SN Ia features that absorption line. Every NUV-blue event also exhibits a low gradient of the Si II ?6355 absorption feature. Many NUV-red events also exhibit a low gradient, perhaps suggestive that NUV-blue events are a subset of the larger low-velocity gradient group.

  1. THE BIRTH RATE OF SNe Ia FROM HYBRID CONe WHITE DWARFS

    SciTech Connect (OSTI)

    Meng, Xiangcun [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Podsiadlowski, Philipp, E-mail: xiangcunmeng@ynao.ac.cn [Department of Astronomy, Oxford University, Oxford OX1 3RH (United Kingdom)

    2014-07-10

    Considering the uncertainties of the C-burning rate (CBR) and the treatment of convective boundaries, Chen et al. found that there is a regime where it is possible to form hybrid CONe white dwarfs (WDs), i.e., ONe WDs with carbon-rich cores. As these hybrid WDs can be as massive as 1.30 M {sub ?}, not much mass needs to be accreted for these objects to reach the Chandrasekhar limit and to explode as Type Ia supernovae (SNe Ia). We have investigated their contribution to the overall SN Ia birth rate and found that such SNe Ia tend to be relatively young with typical time delays between 0.1 and 1 Gyr, where some may be as young as 30 Myr. SNe Ia from hybrid CONe WDs may contribute several percent to all SNe Ia, depending on the common-envelope ejection efficiency and the CBR. We suggest that these SNe Ia may produce part of the 2002cx-like SN Ia class.

  2. Type Ia supernova rate studies from the SDSS-II Supernova Study

    SciTech Connect (OSTI)

    Dilday, Benjamin

    2008-08-01

    The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered ~ 500 spectroscopically confirmed SNe Ia with densely sampled (once every ~ 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents ~ 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SN Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.

  3. On silicon group elements ejected by supernovae type IA

    SciTech Connect (OSTI)

    De, Soma; Timmes, F. X. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Brown, Edward F. [Joint Institute for Nuclear Astrophysics, University of Notre Dame, IN 46556 (United States); Calder, Alan C. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY (United States); Townsley, Dean M. [Department of Physics and Astronomy, The University of Alabama, Tuscaloosa, AL (United States); Athanassiadou, Themis [Swiss National Supercomputing Centre, Via Trevano 131, 6900 Lugano (Switzerland); Chamulak, David A. [Physics Division, Argonne National Laboratory, Argonne, IL (United States); Hawley, Wendy [Laboratoire d'Astrophysique de Marseille, Marseille cedex 13 F-13388 (France); Jack, Dennis, E-mail: somad@asu.edu [Departamento de Astronoma, Universidad de Guanajuato, Apartado Postal 144, 36000 Guanajuato (Mexico)

    2014-06-01

    There is evidence that the peak brightness of a Type Ia supernova is affected by the electron fraction Y {sub e} at the time of the explosion. The electron fraction is set by the aboriginal composition of the white dwarf and the reactions that occur during the pre-explosive convective burning. To date, determining the makeup of the white dwarf progenitor has relied on indirect proxies, such as the average metallicity of the host stellar population. In this paper, we present analytical calculations supporting the idea that the electron fraction of the progenitor systematically influences the nucleosynthesis of silicon group ejecta in Type Ia supernovae. In particular, we suggest the abundances generated in quasi-nuclear statistical equilibrium are preserved during the subsequent freeze-out. This allows potential recovery of Y {sub e} at explosion from the abundances recovered from an observed spectra. We show that measurement of {sup 28}Si, {sup 32}S, {sup 40}Ca, and {sup 54}Fe abundances can be used to construct Y {sub e} in the silicon-rich regions of the supernovae. If these four abundances are determined exactly, they are sufficient to recover Y {sub e} to 6%. This is because these isotopes dominate the composition of silicon-rich material and iron-rich material in quasi-nuclear statistical equilibrium. Analytical analysis shows the {sup 28}Si abundance is insensitive to Y {sub e}, the {sup 32}S abundance has a nearly linear trend with Y {sub e}, and the {sup 40}Ca abundance has a nearly quadratic trend with Y {sub e}. We verify these trends with post-processing of one-dimensional models and show that these trends are reflected in the model's synthetic spectra.

  4. CfA3: 185 TYPE Ia SUPERNOVA LIGHT CURVES FROM THE CfA

    SciTech Connect (OSTI)

    Hicken, Malcolm; Challis, Peter; Kirshner, Robert P.; Bakos, Gaspar; Berlind, Perry; Brown, Warren R.; Caldwell, Nelson; Calkins, Mike; Cho, Richard; Contreras, Maria; Jha, Saurabh; Matheson, Tom; Modjaz, Maryam; Rest, Armin; Michael Wood-Vasey, W.; Barton, Elizabeth J.; Bragg, Ann; Briceno, Cesar; Ciupik, Larry; Dendy, Kristi-Concannon E-mail: kirshner@cfa.harvard.edu

    2009-07-20

    We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains the largest number of homogeneously observed and reduced nearby SNe Ia (z {approx}< 0.08) published to date. It more than doubles the nearby sample, bringing SN Ia cosmology to the point where systematic uncertainties dominate. Our natural system photometry has a precision of {approx}<0.02 mag in BVRIr'i' and {approx}<0.04 mag in U for points brighter than 17.5 mag. We also estimate a systematic uncertainty of 0.03 mag in our SN Ia standard system BVRIr'i' photometry and 0.07 mag for U. Comparisons of our standard system photometry with published SN Ia light curves and comparison stars, where available for the same SN, reveal agreement at the level of a few hundredths mag in most cases. We find that 1991bg-like SNe Ia are sufficiently distinct from other SNe Ia in their color and light-curve-shape/luminosity relation that they should be treated separately in light-curve/distance fitter training samples. The CfA3 sample will contribute to the development of better light-curve/distance fitters, particularly in the few dozen cases where near-infrared photometry has been obtained and, together, can help disentangle host-galaxy reddening from intrinsic supernova color, reducing the systematic uncertainty in SN Ia distances due to dust.

  5. NT~pU.S. Deparfmehnt of Energy P.O0 Bok, 450, MSIN H6-60

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    NT~pU.S. Deparfmehnt of Energy P.O0 Bok, 450, MSIN H6-60 SAT~s ~Richland, Washington 99352 APR 0 12010 1 0-ESQ-093 Mr. Charles G. Spencer, President and Project Manager Washington River Protection Solutions LLC 2440 Stevens Center Place Richland, Washington 99354 Dear Mr. Spencer: CONTRACT NO. DE-AC27-08RVI14800 - DE MINIMIS CHANGES TO THE HANFORD AN ALYTICAL SERVICES QUALITY ASSURANCE REQUIREMENTS DOCUMENT (HASQARD) Compliance with the HASQARD, DOE/RL-96-68, is required by your Contract

  6. Type Ia supernovae yielding distances with 3-4% precision (Journal...

    Office of Scientific and Technical Information (OSTI)

    A paper copy of this document is also available for sale to the public from the National Technical Information Service, Springfield, VA at www.ntis.gov. The luminosities of Type Ia ...

  7. File:USDA-CE-Production-GIFmaps-IA.pdf | Open Energy Information

    Open Energy Info (EERE)

    IA.pdf Jump to: navigation, search File File history File usage Iowa Ethanol Plant Locations Size of this preview: 776 600 pixels. Full resolution (1,650 1,275 pixels,...

  8. Low Mach Number Modeling of Type Ia Supernovae

    SciTech Connect (OSTI)

    Almgren, Ann S.; Bell, John B.; Rendleman, Charles A.; Zingale,Michael

    2005-08-05

    We introduce a low Mach number equation set for the large-scale numerical simulation of carbon-oxygen white dwarfs experiencing a thermonuclear deflagration. Since most of the interesting physics in a Type Ia supernova transpires at Mach numbers from 0.01 to 0.1, such an approach enables both a considerable increase in accuracy and savings in computer time compared with frequently used compressible codes. Our equation set is derived from the fully compressible equations using low Mach number asymptotics, but without any restriction on the size of perturbations in density or temperature. Comparisons with simulations that use the fully compressible equations validate the low Mach number model in regimes where both are applicable. Comparisons to simulations based on the more traditional an elastic approximation also demonstrate the agreement of these models in the regime for which the anelastic approximation is valid. For low Mach number flows with potentially finite amplitude variations in density and temperature, the low Mach number model overcomes the limitations of each of the more traditional models and can serve as the basis for an accurate and efficient simulation tool.

  9. Cosmological parameter uncertainties from SALT-II type Ia supernova light curve models

    SciTech Connect (OSTI)

    Mosher, J.; Sako, M. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Guy, J.; Astier, P.; Betoule, M.; El-Hage, P.; Pain, R.; Regnault, N. [LPNHE, CNRS/IN2P3, Universit Pierre et Marie Curie Paris 6, Universi Denis Diderot Paris 7, 4 place Jussieu, F-75252 Paris Cedex 05 (France); Kessler, R.; Frieman, J. A. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Marriner, J. [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Biswas, R.; Kuhlmann, S. [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States); Schneider, D. P., E-mail: kessler@kicp.chicago.edu [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2014-09-20

    We use simulated type Ia supernova (SN Ia) samples, including both photometry and spectra, to perform the first direct validation of cosmology analysis using the SALT-II light curve model. This validation includes residuals from the light curve training process, systematic biases in SN Ia distance measurements, and a bias on the dark energy equation of state parameter w. Using the SN-analysis package SNANA, we simulate and analyze realistic samples corresponding to the data samples used in the SNLS3 analysis: ?120 low-redshift (z < 0.1) SNe Ia, ?255 Sloan Digital Sky Survey SNe Ia (z < 0.4), and ?290 SNLS SNe Ia (z ? 1). To probe systematic uncertainties in detail, we vary the input spectral model, the model of intrinsic scatter, and the smoothing (i.e., regularization) parameters used during the SALT-II model training. Using realistic intrinsic scatter models results in a slight bias in the ultraviolet portion of the trained SALT-II model, and w biases (w {sub input} w {sub recovered}) ranging from 0.005 0.012 to 0.024 0.010. These biases are indistinguishable from each other within the uncertainty; the average bias on w is 0.014 0.007.

  10. Removing Structural Disorder from Oriented TiO2 Nanotube Arrays: Reducing the Dimensionality of Transport and Recombination in Dye-Sensitized Solar Cells

    SciTech Connect (OSTI)

    Zhu, K.; Vinzant, T. B.; Neale, N. R.; Frank, A. J.

    2007-01-01

    We report on the influence of morphological disorder, arising from bundling of nanotubes (NTs) and microcracks in films of oriented TiO{sub 2} NT arrays, on charge transport and recombination in dye-sensitized solar cells (DSSCs). Capillary stress created during evaporation of liquids from the mesopores of dense TiO{sub 2} NT arrays was of sufficient magnitude to induce bundling and microcrack formation. The average lateral deflection of the NTs in the bundles increased with the surface tension of the liquids and with the film thicknesses. The supercritical CO{sub 2} drying technique was used to produce bundle-free and crack-free NT films. Charge transport and recombination properties of sensitized films were studied by frequency-resolved modulated photocurrent/photovoltage spectroscopies. Transport became significantly faster with decreased clustering of the NTs, indicating that bundling creates additional pathways via intertube contacts. Removing such contacts alters the transport mechanism from a combination of one and three dimensions to the expected one dimension and shortens the electron-transport pathway. Reducing intertube contacts also resulted in a lower density of surface recombination centers by minimizing distortion-induced surface defects in bundled NTs. A causal connection between transport and recombination is observed. The dye coverage was greater in the more aligned NT arrays, suggesting that reducing intertube contacts increases the internal surface area of the films accessible to dye molecules. The solar conversion efficiency and photocurrent density were highest for DSSCs incorporating films with more aligned NT arrays owing to an enhanced light-harvesting efficiency. Removing structural disorder from other materials and devices consisting of nominally one-dimensional architectures (e.g., nanowire arrays) should produce similar effects.

  11. Type Ia supernovae from merging white dwarfs. II. Post-merger detonations

    SciTech Connect (OSTI)

    Raskin, Cody; Kasen, Daniel; Moll, Rainer; Woosley, Stan; Schwab, Josiah

    2014-06-10

    Merging carbon-oxygen (CO) white dwarfs are a promising progenitor system for Type Ia supernovae (SNe Ia), but the underlying physics and timing of the detonation are still debated. If an explosion occurs after the secondary star is fully disrupted, the exploding primary will expand into a dense CO medium that may still have a disk-like structure. This interaction will decelerate and distort the ejecta. Here we carry out multidimensional simulations of 'tamped' SN Ia models, using both particle and grid-based codes to study the merger and explosion dynamics and a radiative transfer code to calculate synthetic spectra and light curves. We find that post-merger explosions exhibit an hourglass-shaped asymmetry, leading to strong variations in the light curves with viewing angle. The two most important factors affecting the outcome are the scale height of the disk, which depends sensitively on the binary mass ratio, and the total {sup 56}Ni yield, which is governed by the central density of the remnant core. The synthetic broadband light curves rise and decline very slowly, and the spectra generally look peculiar, with weak features from intermediate mass elements but relatively strong carbon absorption. We also consider the effects of the viscous evolution of the remnant and show that a longer time delay between merger and explosion probably leads to larger {sup 56}Ni yields and more symmetrical remnants. We discuss the relevance of this class of aspherical 'tamped' SN Ia for explaining the class of 'super-Chandrasekhar' SN Ia.

  12. A=16Al (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (Not observed) See (1986AN07

  13. A=16Mg (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (Not observed) See (1986AN07

  14. A=16Na (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (Not observed) See (1986AN07

  15. A=16Si (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (Not observed) See (1986AN07

  16. A=19Be (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (Not observed) See (1983ANZQ

  17. A=19He (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (Not observed) See (1983ANZQ

  18. A=19Li (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (Not observed) See (1983ANZQ

  19. Ultraviolet observations of Super-Chandrasekhar mass type Ia supernova candidates with swift UVOT

    SciTech Connect (OSTI)

    Brown, Peter J.; Smitka, Michael T.; Krisciunas, Kevin; Wang, Lifan; Kuin, Paul; De Pasquale, Massimiliano; Scalzo, Richard; Holland, Stephen; Milne, Peter

    2014-05-20

    Among Type Ia supernovae (SNe Ia), a class of overluminous objects exist whose ejecta mass is inferred to be larger than the canonical Chandrasekhar mass. We present and discuss the UV/optical photometric light curves, colors, absolute magnitudes, and spectra of three candidate Super-Chandrasekhar mass SNe—2009dc, 2011aa, and 2012dn—observed with the Swift Ultraviolet/Optical Telescope. The light curves are at the broad end for SNe Ia, with the light curves of SN 2011aa being among the broadest ever observed. We find all three to have very blue colors which may provide a means of excluding these overluminous SNe from cosmological analysis, though there is some overlap with the bluest of 'normal' SNe Ia. All three are overluminous in their UV absolute magnitudes compared to normal and broad SNe Ia, but SNe 2011aa and 2012dn are not optically overluminous compared to normal SNe Ia. The integrated luminosity curves of SNe 2011aa and 2012dn in the UVOT range (1600-6000 Å) are only half as bright as SN 2009dc, implying a smaller {sup 56}Ni yield. While it is not enough to strongly affect the bolometric flux, the early time mid-UV flux makes a significant contribution at early times. The strong spectral features in the mid-UV spectra of SNe 2009dc and 2012dn suggest a higher temperature and lower opacity to be the cause of the UV excess rather than a hot, smooth blackbody from shock interaction. Further work is needed to determine the ejecta and {sup 56}Ni masses of SNe 2011aa and 2012dn and to fully explain their high UV luminosities.

  20. Strong near-infrared carbon in the Type Ia supernova iPTF13ebh

    SciTech Connect (OSTI)

    Hsiao, E. Y.; Burns, C. R.; Contreras, C.; Höflich, P.; Sand, D.; Marion, G. H.; Phillips, M. M.; Stritzinger, M.; González-Gaitán, S.; Mason, R. E.; Folatelli, G.; Parent, E.; Gall, C.; Amanullah, R.; Anupama, G. C.; Arcavi, I.; Banerjee, D. P. K.; Beletsky, Y.; Blanc, G. A.; Bloom, J. S.; Brown, P. J.; Campillay, A.; Cao, Y.; De Cia, A.; Diamond, T.; Freedman, W. L.; Gonzalez, C.; Goobar, A.; Holmbo, S.; Howell, D. A.; Johansson, J.; Kasliwal, M. M.; Kirshner, R. P.; Krisciunas, K.; Kulkarni, S. R.; Maguire, K.; Milne, P. A.; Morrell, N.; Nugent, P. E.; Ofek, E. O.; Osip, D.; Palunas, P.; Perley, D. A.; Persson, S. E.; Piro, A. L.; Rabus, M.; Roth, M.; Schiefelbein, J. M.; Srivastav, S.; Sullivan, M.; Suntzeff, N. B.; Surace, J.; Woźniak, P. R.; Yaron, O.

    2015-05-22

    We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated time of explosion. The first NIR spectrum was taken merely 2.3 days after explosion and may be the earliest NIR spectrum yet obtained of a SN Ia. The most striking features in the spectrum are several NIR C I lines, and the C Iλ1.0693 μm line is the strongest ever observed in a SN Ia. Interestingly, no strong optical C II counterparts were found, even though the optical spectroscopic time series began early and is densely cadenced. Except at the very early epochs, within a few days from the time of explosion, we show that the strong NIR C I compared to the weaker optical C II appears to be general in SNe Ia. iPTF13ebh is a fast decliner with Δm15(B) = 1.79 ± 0.01, and its absolute magnitude obeys the linear part of the width-luminosity relation. It is therefore categorized as a “transitional” event, on the fast-declining end of normal SNe Ia as opposed to subluminous/91bg-like objects. iPTF13ebh shows NIR spectroscopic properties that are distinct from both the normal and subluminous/91bg-like classes, bridging the observed characteristics of the two classes. These NIR observations suggest that composition and density of the inner core are similar to that of 91bg-like events, and that it has a deep-reaching carbon burning layer that is not observed in more slowly declining SNe Ia. Furthermore, there is also a substantial difference between the explosion times inferred from the early-time light curve and the velocity evolution of the Si II λ0.6355 μm line, implying a long dark phase of ~4 days.

  1. Strong near-infrared carbon in the Type Ia supernova iPTF13ebh

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hsiao, E. Y.; Burns, C. R.; Contreras, C.; Höflich, P.; Sand, D.; Marion, G. H.; Phillips, M. M.; Stritzinger, M.; González-Gaitán, S.; Mason, R. E.; et al

    2015-05-22

    We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated time of explosion. The first NIR spectrum was taken merely 2.3 days after explosion and may be the earliest NIR spectrum yet obtained of a SN Ia. The most striking features in the spectrum are several NIR C I lines, and the C Iλ1.0693 μm line is the strongest ever observed in a SN Ia. Interestingly, no strong optical C II counterparts were found, even though themore » optical spectroscopic time series began early and is densely cadenced. Except at the very early epochs, within a few days from the time of explosion, we show that the strong NIR C I compared to the weaker optical C II appears to be general in SNe Ia. iPTF13ebh is a fast decliner with Δm15(B) = 1.79 ± 0.01, and its absolute magnitude obeys the linear part of the width-luminosity relation. It is therefore categorized as a “transitional” event, on the fast-declining end of normal SNe Ia as opposed to subluminous/91bg-like objects. iPTF13ebh shows NIR spectroscopic properties that are distinct from both the normal and subluminous/91bg-like classes, bridging the observed characteristics of the two classes. These NIR observations suggest that composition and density of the inner core are similar to that of 91bg-like events, and that it has a deep-reaching carbon burning layer that is not observed in more slowly declining SNe Ia. Furthermore, there is also a substantial difference between the explosion times inferred from the early-time light curve and the velocity evolution of the Si II λ0.6355 μm line, implying a long dark phase of ~4 days.« less

  2. Strong near-infrared carbon in the Type Ia supernova iPTF13ebh

    SciTech Connect (OSTI)

    Hsiao, E. Y.; Burns, C. R.; Contreras, C.; Hflich, P.; Sand, D.; Marion, G. H.; Phillips, M. M.; Stritzinger, M.; Gonzlez-Gaitn, S.; Mason, R. E.; Folatelli, G.; Parent, E.; Gall, C.; Amanullah, R.; Anupama, G. C.; Arcavi, I.; Banerjee, D. P. K.; Beletsky, Y.; Blanc, G. A.; Bloom, J. S.; Brown, P. J.; Campillay, A.; Cao, Y.; De Cia, A.; Diamond, T.; Freedman, W. L.; Gonzalez, C.; Goobar, A.; Holmbo, S.; Howell, D. A.; Johansson, J.; Kasliwal, M. M.; Kirshner, R. P.; Krisciunas, K.; Kulkarni, S. R.; Maguire, K.; Milne, P. A.; Morrell, N.; Nugent, P. E.; Ofek, E. O.; Osip, D.; Palunas, P.; Perley, D. A.; Persson, S. E.; Piro, A. L.; Rabus, M.; Roth, M.; Schiefelbein, J. M.; Srivastav, S.; Sullivan, M.; Suntzeff, N. B.; Surace, J.; Wo?niak, P. R.; Yaron, O.

    2015-05-22

    We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated time of explosion. The first NIR spectrum was taken merely 2.3 days after explosion and may be the earliest NIR spectrum yet obtained of a SN Ia. The most striking features in the spectrum are several NIR C I lines, and the C I?1.0693 ?m line is the strongest ever observed in a SN Ia. Interestingly, no strong optical C II counterparts were found, even though the optical spectroscopic time series began early and is densely cadenced. Except at the very early epochs, within a few days from the time of explosion, we show that the strong NIR C I compared to the weaker optical C II appears to be general in SNe Ia. iPTF13ebh is a fast decliner with ?m15(B) = 1.79 0.01, and its absolute magnitude obeys the linear part of the width-luminosity relation. It is therefore categorized as a transitional event, on the fast-declining end of normal SNe Ia as opposed to subluminous/91bg-like objects. iPTF13ebh shows NIR spectroscopic properties that are distinct from both the normal and subluminous/91bg-like classes, bridging the observed characteristics of the two classes. These NIR observations suggest that composition and density of the inner core are similar to that of 91bg-like events, and that it has a deep-reaching carbon burning layer that is not observed in more slowly declining SNe Ia. Furthermore, there is also a substantial difference between the explosion times inferred from the early-time light curve and the velocity evolution of the Si II ?0.6355 ?m line, implying a long dark phase of ~4 days.

  3. TYPE Ia SUPERNOVA COLORS AND EJECTA VELOCITIES: HIERARCHICAL BAYESIAN REGRESSION WITH NON-GAUSSIAN DISTRIBUTIONS

    SciTech Connect (OSTI)

    Mandel, Kaisey S.; Kirshner, Robert P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Foley, Ryan J., E-mail: kmandel@cfa.harvard.edu [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States)

    2014-12-20

    We investigate the statistical dependence of the peak intrinsic colors of Type Ia supernovae (SNe Ia) on their expansion velocities at maximum light, measured from the Si II ?6355 spectral feature. We construct a new hierarchical Bayesian regression model, accounting for the random effects of intrinsic scatter, measurement error, and reddening by host galaxy dust, and implement a Gibbs sampler and deviance information criteria to estimate the correlation. The method is applied to the apparent colors from BVRI light curves and Si II velocity data for 79 nearby SNe Ia. The apparent color distributions of high-velocity (HV) and normal velocity (NV) supernovae exhibit significant discrepancies for B V and B R, but not other colors. Hence, they are likely due to intrinsic color differences originating in the B band, rather than dust reddening. The mean intrinsic B V and B R color differences between HV and NV groups are 0.06 0.02 and 0.09 0.02 mag, respectively. A linear model finds significant slopes of 0.021 0.006 and 0.030 0.009 mag (10{sup 3} km s{sup 1}){sup 1} for intrinsic B V and B R colors versus velocity, respectively. Because the ejecta velocity distribution is skewed toward high velocities, these effects imply non-Gaussian intrinsic color distributions with skewness up to +0.3. Accounting for the intrinsic-color-velocity correlation results in corrections to A{sub V} extinction estimates as large as 0.12 mag for HV SNe Ia and +0.06 mag for NV events. Velocity measurements from SN Ia spectra have the potential to diminish systematic errors from the confounding of intrinsic colors and dust reddening affecting supernova distances.

  4. Type Ia supernova rate measurements to redshift 2.5 from CANDELS: Searching for prompt explosions in the early universe

    SciTech Connect (OSTI)

    Rodney, Steven A.; Riess, Adam G.; Graur, Or; Jones, David O. [Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218 (United States); Strolger, Louis-Gregory; Dahlen, Tomas; Casertano, Stefano; Ferguson, Henry C.; Koekemoer, Anton M. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Dickinson, Mark E. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Garnavich, Peter [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Hayden, Brian [E.O. Lawrence Berkeley National Lab, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Jha, Saurabh W.; McCully, Curtis; Patel, Brandon [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Kirshner, Robert P. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Mobasher, Bahram [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Weiner, Benjamin J. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Cenko, S. Bradley [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Clubb, Kelsey I. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); and others

    2014-07-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of ?0.25 deg{sup 2} with ?900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z ? 2.5. We classify ?24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z = 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only ?3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (<500 Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction is f{sub P} = 0.53{sub stat0.10}{sup 0.09}{sub sys0.26}{sup 0.10}, consistent with a delay time distribution that follows a simple t {sup 1} power law for all times t > 40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20% of all SN Ia explosionsthough further analysis and larger samples will be needed to examine that suggestion.

  5. SNe Ia tests of quintessence tracker cosmology in an anisotropic background

    SciTech Connect (OSTI)

    Miranda, W.; Carneiro, S.; Pigozzo, C. E-mail: saulo.carneiro@pq.cnpq.br

    2014-07-01

    We investigate the observational effects of a quintessence model in an anisotropic spacetime. The anisotropic metric is a non-rotating particular case of a generalized Gödel's metric and is classified as Bianchi III. This metric is an exact solution of the Einstein-Klein-Gordon field equations with an anisotropic scalar field ψ, which is responsible for the anisotropy of the spacetime geometry. We test the model against observations of type Ia supernovae, analyzing the SDSS dataset calibrated with the MLCS2k2 fitter, and the results are compared to standard quintessence models with Ratra-Peebles potentials. We obtain a good agreement with observations, with best values for the matter and curvature density parameters Ω{sub M} = 0.29 and Ω{sub k}= 0.01 respectively. We conclude that present SNe Ia observations cannot, alone, distinguish a possible anisotropic axis in the cosmos.

  6. THE EARLIEST NEAR-INFRARED TIME-SERIES SPECTROSCOPY OF A TYPE Ia SUPERNOVA

    SciTech Connect (OSTI)

    Hsiao, E. Y.; Phillips, M. M.; Morrell, N.; Contreras, C.; Roth, M.; Marion, G. H.; Kirshner, R. P.; Burns, C. R.; Freedman, W. L.; Persson, S. E.; Winge, C.; Gerardy, C. L.; Hoeflich, P.; Im, M.; Jeon, Y.; Pignata, G.; Stanishev, V.; and others

    2013-04-01

    We present ten medium-resolution, high signal-to-noise ratio near-infrared (NIR) spectra of SN 2011fe from SpeX on the NASA Infrared Telescope Facility (IRTF) and Gemini Near-Infrared Spectrograph (GNIRS) on Gemini North, obtained as part of the Carnegie Supernova Project. This data set constitutes the earliest time-series NIR spectroscopy of a Type Ia supernova (SN Ia), with the first spectrum obtained at 2.58 days past the explosion and covering -14.6 to +17.3 days relative to B-band maximum. C I {lambda}1.0693 {mu}m is detected in SN 2011fe with increasing strength up to maximum light. The delay in the onset of the NIR C I line demonstrates its potential to be an effective tracer of unprocessed material. For the first time in a SN Ia, the early rapid decline of the Mg II {lambda}1.0927 {mu}m velocity was observed, and the subsequent velocity is remarkably constant. The Mg II velocity during this constant phase locates the inner edge of carbon burning and probes the conditions under which the transition from deflagration to detonation occurs. We show that the Mg II velocity does not correlate with the optical light-curve decline rate {Delta}m{sub 15}(B). The prominent break at {approx}1.5 {mu}m is the main source of concern for NIR k-correction calculations. We demonstrate here that the feature has a uniform time evolution among SNe Ia, with the flux ratio across the break strongly correlated with {Delta}m{sub 15}(B). The predictability of the strength and the onset of this feature suggests that the associated k-correction uncertainties can be minimized with improved spectral templates.

  7. Comparing the host galaxies of type Ia, type II, and type Ibc supernovae

    SciTech Connect (OSTI)

    Shao, X.; Liang, Y. C.; Chen, X. Y.; Zhong, G. H.; Deng, L. C.; Zhang, B.; Shi, W. B.; Zhou, L.; Dennefeld, M.; Hammer, F.; Flores, H. E-mail: ycliang@bao.ac.cn

    2014-08-10

    We compare the host galaxies of 902 supernovae (SNe), including SNe Ia, SNe II, and SNe Ibc, which are selected by cross-matching the Asiago Supernova Catalog with the Sloan Digital Sky Survey (SDSS) Data Release 7. We selected an additional 213 galaxies by requiring the light fraction of spectral observations to be >15%, which could represent well the global properties of the galaxies. Among these 213 galaxies, 135 appear on the Baldwin-Phillips-Terlevich diagram, which allows us to compare the hosts in terms of whether they are star-forming (SF) galaxies, active galactic nuclei (AGNs; including composites, LINERs, and Seyfert 2s) or absorption-line galaxies (Absorps; i.e., their related emission lines are weak or non-existent). The diagrams related to the parameters D{sub n}(4000), H?{sub A}, stellar masses, star formation rates (SFRs), and specific SFRs for the SNe hosts show that almost all SNe II and most of the SNe Ibc occur in SF galaxies, which have a wide range of stellar masses and low D{sub n}(4000). The SNe Ia hosts as SF galaxies following similar trends. A significant fraction of SNe Ia occurs in AGNs and absorption-line galaxies, which are massive and have high D{sub n}(4000). The stellar population analysis from spectral synthesis fitting shows that the hosts of SNe II have a younger stellar population than hosts of SNe Ia. These results are compared with those of the 689 comparison galaxies where the SDSS fiber captures less than 15% of the total light. These comparison galaxies appear biased toward higher 12+log(O/H) (?0.1 dex) at a given stellar mass. Therefore, we believe the aperture effect should be kept in mind when the properties of the hosts for different types of SNe are discussed.

  8. Optical and ultraviolet observations of the narrow-lined type Ia SN 2012fr in NGC 1365

    SciTech Connect (OSTI)

    Zhang, Ju-Jia; Bai, Jin-Ming; Wang, Bo; Liu, Zheng-Wei [Yunnan Observatories (YNAO), Chinese Academy of Sciences, Kunming 650011 (China); Wang, Xiao-Feng; Zhao, Xu-Lin; Chen, Jun-Cheng [Physics Department and Tsinghua Center for Astrophysics (THCA), Tsinghua University, Beijing 100084 (China); Zhang, Tian-Meng, E-mail: jujia@ynao.ac.cn, E-mail: baijinming@ynao.ac.cn, E-mail: wang_xf@mail.tsinghua.edu.cn [National Astronomical Observatories of China (NAOC), Chinese Academy of Sciences, Beijing 100012 (China)

    2014-07-01

    Extensive optical and ultraviolet (UV) observations of the type Ia supernova (SN Ia) 2012fr are presented in this paper. It has a relatively high luminosity, with an absolute B-band peak magnitude of about 19.5 mag and a smaller post-maximum decline rate than normal SNe Ia (e.g., ?m {sub 15}(B) =0.85 0.05 mag). Based on the UV and optical light curves, we derived that a {sup 56}Ni mass of about 0.88 M {sub ?} was synthesized in the explosion. The earlier spectra are characterized by noticeable high-velocity features of Si II ?6355 and Ca II with velocities in the range of ?22, 000-25, 000 km s{sup 1}. At around the maximum light, these spectral features are dominated by the photospheric components which are noticeably narrower than normal SNe Ia. The post-maximum velocity of the photosphere remains almost constant at ?12,000 km s{sup 1} for about one month, reminiscent of the behavior of some luminous SNe Ia like SN 1991T. We propose that SN 2012fr may represent a subset of the SN 1991T-like SNe Ia viewed in a direction with a clumpy or shell-like structure of ejecta, in terms of a significant level of polarization reported in Maund et al. in 2013.

  9. A=10F (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (Not illustrated) Not observed: see (1979AJ01). See also (1988AJ01

  10. A=10Ne (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (Not illustrated) Not observed: see (1979AJ01). See also (1988AJ01

  11. A=10O (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (Not illustrated) Not observed: see (1979AJ01). See also (1988AJ01

  12. A=17Al (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Al (1993TI07) (Not observed) See (1983ANZQ, 1988WA18, 1992AV03).

  13. A=17He (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (Not illustrated) Not observed: see (1986AJ04, 1988POZS

  14. A=17Li (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (Not illustrated) Not observed: see (1986AJ04, 1988POZS

  15. A=17Mg (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mg (1993TI07) (Not observed) See (1983ANZQ, 1988WA18, 1992AV03).

  16. A=17P (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (Not observed) See (1983ANZQ, 1988WA18, 1992AV03

  17. A=17Si (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Si (1993TI07) (Not observed) See (1983ANZQ, 1988WA18, 1992AV03).

  18. A=18He (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (Not illustrated) Not observed: See (1982AV1A, 1983ANZQ

  19. A=20Al, etc. (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    98TI06) (Not observed) See (1972AJ02, 1983ANZQ, 1986AN07

  20. A=20Be (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    98TI06) (Not observed) See (1977CE05, 1983ANZQ, 1986AN07, 1987SIZX

  1. A=20n (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    98TI06) (Not observed) See (1977CE05, 1983ANZQ, 1986AN07, 1987SIZX

  2. Hard X-ray emission and {sup 44}Ti line features of the Tycho supernova remnant

    SciTech Connect (OSTI)

    Wang, Wei [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Li, Zhuo, E-mail: wangwei@bao.ac.cn, E-mail: zhuo.li@pku.edu.cn [Department of Astronomy and Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2014-07-10

    A deep hard X-ray survey of the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has detected for the first time non-thermal emission up to 90 keV in the Tycho supernova (SN) remnant. Its 3-100 keV spectrum is fitted with a thermal bremsstrahlung of kT ? 0.81 0.45 keV plus a power-law model of ? ? 3.01 0.16. Based on diffusive shock acceleration theory, this non-thermal emission, together with radio measurements, implies that the Tycho remnant may not accelerate protons up to >PeV but to hundreds TeV. Only heavier nuclei may be accelerated to the cosmic ray spectral 'knee'. In addition, using INTEGRAL, we search for soft gamma-ray lines at 67.9 and 78.4 keV that come from the decay of radioactive {sup 44}Ti in the Tycho remnant. A bump feature in the 60-90 keV energy band, potentially associated with the {sup 44}Ti line emission, is found with a marginal significance level of ?2.6?. The corresponding 3? upper limit on the {sup 44}Ti line flux amounts to 1.5 10{sup 5} photon cm{sup 2} s{sup 1}. Implications on the progenitor of the Tycho SN, considered to be a Type Ia SN prototype, are discussed.

  3. A SUPER-EDDINGTON WIND SCENARIO FOR THE PROGENITORS OF TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Ma, Xin; Chen, Xuefei; Chen, Hai-liang; Han, Zhanwen; Denissenkov, Pavel A. E-mail: cxf@ynao.ac.cn

    2013-12-01

    The accretion of hydrogen-rich material on to carbon-oxygen white dwarfs (CO WDs) is crucial for understanding Type Ia supernova (SN Ia) from the single-degenerate model, but this process has not been well understood due to the numerical difficulties in treating H and He flashes during the accretion. For CO WD masses from 0.5 to 1.378 M {sub ?} and accretion rates in the range from 10{sup 8} to 10{sup 5} M {sub ?} yr{sup 1}, we simulated the accretion of solar-composition material on to CO WDs using the state-of-the-art stellar evolution code of MESA. For comparison with steady-state models, we first ignored the contribution from nuclear burning to the luminosity when determining the Eddington accretion rate, and found that the properties of H burning in our accreting CO WD models are similar to those from the steady-state models, except that the critical accretion rates at which the WDs turn into red giants or H-shell flashes occur on their surfaces are slightly higher than those from the steady-state models. However, the super-Eddington wind is triggered at much lower accretion rates than previously thought, when the contribution of nuclear burning to the total luminosity is included. This super-Eddington wind naturally prevents the CO WDs with high accretion rates from becoming red giants, thus presenting an alternative to the optically thick wind proposed by Hachisu etal. Furthermore, the super-Eddington wind works in low-metallicity environments, which may explain SNe Ia observed at high redshifts.

  4. SPECTROPOLARIMETRY OF THE TYPE Ia SN 2007sr TWO MONTHS AFTER MAXIMUM LIGHT

    SciTech Connect (OSTI)

    Zelaya, P.; Quinn, J. R.; Clocchiatti, A.; Baade, D.; Patat, F.; Hoeflich, P.; Maund, J.; Wang, L.; Wheeler, J. C.

    2013-02-01

    We present late-time spectropolarimetric observations of SN 2007sr, obtained with the Very Large Telescope at the ESO Paranal Observatory when the object was 63 days after maximum light. The late-time spectrum displays strong line polarization in the Ca II absorption features. SN 2007sr adds to the case of some normal Type Ia supernovae that show high line polarization or repolarization at late times, a fact that might be connected with the presence of high-velocity features at early times.

  5. Spectroscopic Determination of the Low Redshift Type Ia Supernova Rate from the Sloan Digital Sky Survey

    SciTech Connect (OSTI)

    Krughoff, K. S.; Connolly, Andrew J.; Frieman, Joshua; SubbaRao, Mark; Kilper, Gary; Schneider, Donald P.

    2011-04-10

    Supernova rates are directly coupled to high mass stellar birth and evolution. As such, they are one of the few direct measures of the history of cosmic stellar evolution. In this paper we describe an probabilistic technique for identifying supernovae within spectroscopic samples of galaxies. We present a study of 52 type Ia supernovae ranging in age from -14 days to +40 days extracted from a parent sample of \\simeq 50,000 spectra from the SDSS DR5. We find a Supernova Rate (SNR) of 0.472^{+0.048}_{-0.039}(Systematic)^{+0.081}_{-0.071}(Statistical)SNu at a redshift of = 0.1. This value is higher than other values at low redshift at the 1{\\sigma}, but is consistent at the 3{\\sigma} level. The 52 supernova candidates used in this study comprise the third largest sample of supernovae used in a type Ia rate determination to date. In this paper we demonstrate the potential for the described approach for detecting supernovae in future spectroscopic surveys.

  6. TYCHO SN 1572: A NAKED Ia SUPERNOVA REMNANT WITHOUT AN ASSOCIATED AMBIENT MOLECULAR CLOUD

    SciTech Connect (OSTI)

    Tian, W. W.; Leahy, D. A.

    2011-03-10

    The historical supernova remnant (SNR) Tycho SN 1572 originates from the explosion of a normal Type Ia supernova that is believed to have originated from a carbon-oxygen white dwarf in a binary system. We analyze the 21 cm continuum, H I, and {sup 12}CO-line data from the Canadian Galactic Plane Survey in the direction of SN 1572 and the surrounding region. We construct H I absorption spectra to SN 1572 and three nearby compact sources. We conclude that SN 1572 has no molecular cloud interaction, which argues against previous claims that a molecular cloud is interacting with the SNR. This new result does not support a recent claim that dust, newly detected by AKARI, originates from such an SNR-cloud interaction. We suggest that the SNR has a kinematic distance of 2.5-3.0 kpc based on a nonlinear rotational curve model. Very high energy {gamma}-ray emission from the remnant has been detected by the VERITAS telescope, so our result shows that its origin should not be an SNR-cloud interaction. Both radio and X-ray observations support that SN 1572 is an isolated Type Ia SNR.

  7. Spectroscopic Observations and Analysis of the Unusual Type Ia SN1999ac

    SciTech Connect (OSTI)

    Garavini, G.; Aldering, G.; Amadon, A.; Amanullah, R.; Astier,P.; Balland, C.; Blanc, G.; Conley, A.; Dahlen, T.; Deustua, S.E.; Ellis,R.; Fabbro, S.; Fadeyev, V.; Fan, X.; Folatelli, G.; Frye, B.; Gates,E.L.; Gibbons, R.; Goldhaber, G.; Goldman, B.; Goobar, A.; Groom, D.E.; Haissinski, J.; Hardin, D.; Hook, I.; Howell, D.A.; Kent, S.; Kim, A.G.; Knop, R.A.; Kowalski, M.; Kuznetsova, N.; Lee, B.C.; Lidman, C.; Mendez,J.; Miller, G.J.; Moniez, M.; Mouchet, M.; Mourao, A.; Newberg, H.; Nobili, S.; Nugent, P.E.; Pain, R.; Perdereau, O.; Perlmutter, S.; Quimby, R.; Regnault, N.; Rich, J.; Richards, G.T.; Ruiz-Lapuente, P.; Schaefer, B.E.; Schahmaneche, K.; Smith, E.; Spadafora, A.L.; Stanishev,V.; Thomas, R.C.; Walton, N.A.; Wang, L.; Wood-Vasey, W.M.

    2005-07-12

    The authors present optical spectra of the peculiar Type Ia supernova (SN Ia) 1999ac. The data extend from -15 to +42 days with respect to B-band maximum and reveal an event that is unusual in several respects. prior to B-band maximum, the spectra resemble those of SN 1999aa, a slowly declining event, but possess stronger Si II and Ca II signatures (more characteristic of a spectroscopically normal SN). Spectra after B-band maximum appear more normal. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from Si II are among the slowest ever observed, though SN 1999ac is not particularly dim. The analysis of the parameters v{sub 10}(Si II), R(Si II), v, and {Delta}m{sub 15} further underlines the unique characteristics of SN 1999ac. They find convincing evidence of C II {lambda}6580 in the day -15 spectrum with ejection velocity v > 16,000 km s{sup -1}, but this signature disappears by day -9. This rapid evolution at early times highlights the importance of extremely early-time spectroscopy.

  8. Consistent use of type Ia supernovae highly magnified by galaxy clusters to constrain the cosmological parameters

    SciTech Connect (OSTI)

    Zitrin, Adi [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Redlich, Matthias [Universitt Heidelberg, Zentrum fr Astronomie, Institut fr Theoretische Astrophysik, Philosophenweg 12, D-69120 Heidelberg (Germany); Broadhurst, Tom, E-mail: adizitrin@gmail.com [Department of Theoretical Physics, University of Basque Country UPV/EHU, Bilbao (Spain)

    2014-07-01

    We discuss how Type Ia supernovae (SNe) strongly magnified by foreground galaxy clusters should be self-consistently treated when used in samples fitted for the cosmological parameters. While the cluster lens magnification of a SN can be well constrained from sets of multiple images of various background galaxies with measured redshifts, its value is typically dependent on the fiducial set of cosmological parameters used to construct the mass model. In such cases, one should not naively demagnify the observed SN luminosity by the model magnification into the expected Hubble diagram, which would create a bias, but instead take into account the cosmological parameters a priori chosen to construct the mass model. We quantify the effect and find that a systematic error of typically a few percent, up to a few dozen percent per magnified SN may be propagated onto a cosmological parameter fit unless the cosmology assumed for the mass model is taken into account (the bias can be even larger if the SN is lying very near the critical curves). We also simulate how such a bias propagates onto the cosmological parameter fit using the Union2.1 sample supplemented with strongly magnified SNe. The resulting bias on the deduced cosmological parameters is generally at the few percent level, if only few biased SNe are included, and increases with the number of lensed SNe and their redshift. Samples containing magnified Type Ia SNe, e.g., from ongoing cluster surveys, should readily account for this possible bias.

  9. Toward Exascale Computing of Type Ia and Ib,c Supernovae: V&V of Current

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Models | Argonne Leadership Computing Facility Toward Exascale Computing of Type Ia and Ib,c Supernovae: V&V of Current Models PI Name: Don Lamb PI Email: lamb@oddjob.uchicago.edu Institution: University Of Chicago Allocation Program: INCITE Allocation Hours at ALCF: 40,000,000 Year: 2012 Research Domain: Physics This project continues a program of verification and validation of Type Ia supernova models. More 3-D simulations of the explosion phase will be performed, along with 2-D

  10. A=20He (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    He (1998TI06) (Not observed) See (1977CE05, 1983ANZQ, 1986AN07, 1987SIZX).

  11. A=20Li (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Li (1998TI06) (Not observed) See (1977CE05, 1983ANZQ, 1986AN07, 1987SIZX).

  12. A=5n (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (Not illustrated) See also the A = 5 introductory discussion titled A = 5 resonance parameters.

  13. Near-infrared line identification in type Ia supernovae during the transitional phase

    SciTech Connect (OSTI)

    Friesen, Brian; Baron, E.; Wisniewski, John P.; Miller, Timothy R.; Parrent, Jerod T.; Thomas, R. C.; Marion, G. H.

    2014-09-10

    We present near-infrared synthetic spectra of a delayed-detonation hydrodynamical model and compare them to observed spectra of four normal Type Ia supernovae ranging from day +56.5 to day +85. This is the epoch during which supernovae are believed to be undergoing the transition from the photospheric phase, where spectra are characterized by line scattering above an optically thick photosphere, to the nebular phase, where spectra consist of optically thin emission from forbidden lines. We find that most spectral features in the near-infrared can be accounted for by permitted lines of Fe II and Co II. In addition, we find that [Ni II] fits the emission feature near 1.98 μm, suggesting that a substantial mass of {sup 58}Ni exists near the center of the ejecta in these objects, arising from nuclear burning at high density.

  14. EARLY OBSERVATIONS AND ANALYSIS OF THE TYPE Ia SN 2014J IN M82

    SciTech Connect (OSTI)

    Marion, G. H.; Vinkó, J.; Sand, D. J.; Hsiao, E. Y.; Banerjee, D. P. K.; Joshi, V.; Venkataraman, V.; Ashok, N. M.; Valenti, S.; Howell, D. A.; Stritzinger, M. D.; Amanullah, R.; Johansson, J.; Binzel, R. P.; Bochanski, J. J.; Bryngelson, G. L.; Burns, C. R.; Drozdov, D.; Fieber-Beyer, S. K.; Graham, M. L.; and others

    2015-01-01

    We present optical and near infrared (NIR) observations of the nearby Type Ia SN 2014J. Seventeen optical and 23 NIR spectra were obtained from 10 days before (–10d) to 10 days after (+10d) the time of maximum B-band brightness. The relative strengths of absorption features and their patterns of development can be compared at one day intervals throughout most of this period. Carbon is not detected in the optical spectra, but we identify C I λ1.0693 in the NIR spectra. Mg II lines with high oscillator strengths have higher initial velocities than other Mg II lines. We show that the velocity differences can be explained by differences in optical depths due to oscillator strengths. The spectra of SN 2014J show that it is a normal SN Ia, but many parameters are near the boundaries between normal and high-velocity subclasses. The velocities for O I, Mg II, Si II, S II, Ca II, and Fe II suggest that SN 2014J has a layered structure with little or no mixing. That result is consistent with the delayed detonation explosion models. We also report photometric observations, obtained from –10d to +29d, in the UBVRIJH and K{sub s} bands. The template fitting package SNooPy is used to interpret the light curves and to derive photometric parameters. Using R{sub V} = 1.46, which is consistent with previous studies, SNooPy finds that A{sub V} = 1.80 for E(B – V){sub host} = 1.23 ± 0.06 mag. The maximum B-band brightness of –19.19 ± 0.10 mag was reached on February 1.74 UT ± 0.13 days and the supernova has a decline parameter, Δm {sub 15}, of 1.12 ± 0.02 mag.

  15. Measurements of the Rate of Type Ia Supernovae at Redshift z < ~0.3 from the SDSS-II Supernova Survey

    SciTech Connect (OSTI)

    Dilday, Benjamin; Smith, Mathew; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Castander, Francisco; Cinabro, David; Filippenko, Alexei V.; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter M.; /Notre Dame U. /Stockholm U., OKC /Stockholm U.

    2010-01-01

    We present a measurement of the volumetric Type Ia supernova (SN Ia) rate based on data from the Sloan Digital Sky Survey II (SDSS-II) Supernova Survey. The adopted sample of supernovae (SNe) includes 516 SNe Ia at redshift z {approx}< 0.3, of which 270 (52%) are spectroscopically identified as SNe Ia. The remaining 246 SNe Ia were identified through their light curves; 113 of these objects have spectroscopic redshifts from spectra of their host galaxy, and 133 have photometric redshifts estimated from the SN light curves. Based on consideration of 87 spectroscopically confirmed non-Ia SNe discovered by the SDSS-II SN Survey, we estimate that 2.04{sub -0.95}{sup +1.61}% of the photometric SNe Ia may be misidentified. The sample of SNe Ia used in this measurement represents an order of magnitude increase in the statistics for SN Ia rate measurements in the redshift range covered by the SDSS-II Supernova Survey. If we assume a SN Ia rate that is constant at low redshift (z < 0.15), then the SN observations can be used to infer a value of the SN rate of r{sub V} = (2.69{sub -0.30-0.01}{sup +0.34+0.21}) x 10{sup -5} SNe yr{sup -1} Mpc{sup -3} (H{sub 0}/(70 km s{sup -1} Mpc{sup -1})){sup 3} at a mean redshift of {approx} 0.12, based on 79 SNe Ia of which 72 are spectroscopically confirmed. However, the large sample of SNe Ia included in this study allows us to place constraints on the redshift dependence of the SN Ia rate based on the SDSS-II Supernova Survey data alone. Fitting a power-law model of the SN rate evolution, r{sub V} (z) = A{sub p} x ((1+z)/(1+z{sub 0})){sup {nu}}, over the redshift range 0.0 < z < 0.3 with z{sub 0} = 0.21, results in A{sub p} = (3.43{sub -0.15}{sup +0.15}) x 10{sup -5} SNe yr{sup -1} Mpc{sup -3} (H{sub 0}/(70 km s{sup -1} Mpc{sup -1})){sup 3} and {nu} = 2.04{sub -0.89}{sup +0.90}.

  16. EVOLUTION OF POST-IMPACT REMNANT HELIUM STARS IN TYPE Ia SUPERNOVA REMNANTS WITHIN THE SINGLE-DEGENERATE SCENARIO

    SciTech Connect (OSTI)

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E. E-mail: pmricker@illinois.edu

    2013-08-10

    The progenitor systems of Type Ia supernovae (SNe Ia) are still under debate. Based on recent hydrodynamics simulations, non-degenerate companions in the single-degenerate scenario (SDS) should survive the supernova (SN) impact. One way to distinguish between the SDS and the double-degenerate scenario is to search for the post-impact remnant stars (PIRSs) in SN Ia remnants. Using a technique that combines multi-dimensional hydrodynamics simulations with one-dimensional stellar evolution simulations, we have examined the post-impact evolution of helium-rich binary companions in the SDS. It is found that these helium-rich PIRSs (He PIRSs) dramatically expand and evolve to a luminous phase (L {approx} 10{sup 4} L{sub Sun }) about 10 yr after an SN explosion. Subsequently, they contract and evolve to become hot blue-subdwarf-like (sdO-like) stars by releasing gravitational energy, persisting as sdO-like stars for several million years before evolving to the helium red-giant phase. We therefore predict that a luminous OB-like star should be detectable within {approx}30 yr after the SN explosion. Thereafter, it will shrink and become an sdO-like star in the central regions of SN Ia remnants within star-forming regions for SN Ia progenitors evolved via the helium-star channel in the SDS. These He PIRSs are predicted to be rapidly rotating (v{sub rot} {approx}> 50 km s{sup -1}) and to have high spatial velocities (v{sub linear} {approx}> 500 km s{sup -1}). Furthermore, if SN remnants have diffused away and are not recognizable at a later stage, He PIRSs could be an additional source of single sdO stars and/or hypervelocity stars.

  17. Infrared spectroscopy of CaTiO3, SrTiO3, BaTiO3, Ba0.5Sr0.5TiO3...

    Office of Scientific and Technical Information (OSTI)

    Infrared spectroscopy of CaTiO3, SrTiO3, BaTiO3, Ba0.5Sr0.5TiO3 thin films, and (BaTiO3)5(SrTiO3)5 superlattice grown on SrRuO3SrTiO3(001) substrates Citation Details In-Document ...

  18. Magnetic Hardening of CeFe11Ti and the Effect of TiC Addition...

    Office of Scientific and Technical Information (OSTI)

    Magnetic Hardening of CeFe11Ti and the Effect of TiC Addition Citation ... Publication Date: 2015-04-01 OSTI Identifier: 1221660 Report Number(s): IS-J 8423 Journal ID: ISSN ...

  19. A Measurement of the Rate of Type Ia Supernovae in Galaxy Clusters from the SDSS-II Supernova Survey

    SciTech Connect (OSTI)

    Dilday, Benjamin; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Castander, Francisco; Cinabro, David; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter; Goobar, Ariel; Hopp, Ulrich; /Munich, Tech. U. /Munich U. Observ. /Tokyo U.

    2010-03-01

    We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z {le} 0.17 and 27 SN events in 492 maxBCG clusters at 0.1 {le} z {le} 0.3. We find values for the cluster SN Ia rate of (0.37{sub -0.12-0.01}{sup +0.17+0.01}) SNur h{sup 2} and (0.55{sub -0.11-0.01}{sup +0.13+0.02}) SNur h{sup 2} (SNux = 10{sup -12}L{sub x{circle_dot}}{sup -1} yr{sup -1}) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be (0.31{sub -0.12-0.01}{sup +0.18+0.01}) SNur h{sup 2} and (0.49{sub -0.11-0.01}{sup +0.15+0.02}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be (2.04{sub -1.11-0.04}{sup +1.99+0.07}) SNur h{sup 2} and (0.36{sub -0.30-0.01}{sup +0.84+0.01}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The ratio of the SN Ia rate in cluster early-type galaxies to that of the SN Ia rate in field early-type galaxies is 1.94{sub -0.91-0.015}{sup +1.31+0.043} and 3.02{sub -1.03-0.048}{sup +1.31+0.062}, for C4 and maxBCG clusters, respectively. The SN rate in galaxy clusters as a function of redshift, which probes the late time SN Ia delay distribution, shows only weak dependence on redshift. Combining our current measurements with previous measurements, we fit the cluster SN Ia rate data to a linear function of redshift, and find r{sub L} = [(0.49{sub -0.14}{sup +0.15}) + (0.91{sub -0.81}{sup +0.85}) x z] SNuB h{sup 2}. A comparison of the radial distribution of SNe in cluster to field early-type galaxies shows possible evidence for an enhancement of the SN rate in the cores of cluster early-type galaxies. With an observation of at most 3 hostless, intra-cluster SNe Ia, we estimate the fraction of cluster SNe that are

  20. PRODUCTION OF THE p-PROCESS NUCLEI IN THE CARBON-DEFLAGRATION MODEL FOR TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Kusakabe, Motohiko; Iwamoto, Nobuyuki; Nomoto, Ken'ichi E-mail: iwamoto.nobuyuki@jaea.go.jp

    2011-01-01

    We calculate the nucleosynthesis of proton-rich isotopes in the carbon-deflagration model for Type Ia supernovae (SNe Ia). The seed abundances are obtained by calculating the s-process nucleosynthesis that is expected to occur in the repeating helium shell flashes on the carbon-oxygen (CO) white dwarf (WD) during mass accretion from a binary companion. When the deflagration wave passes through the outer layer of the CO WD, p-nuclei are produced by photodisintegration reactions on s-nuclei in a region where the peak temperature ranges from 1.9 to 3.6 x 10{sup 9} K. We confirm the sensitivity of the p-process on the initial distribution of s-nuclei. We show that the initial C/O ratio in the WD does not affect much the yield of p-nuclei. On the other hand, the abundance of {sup 22}Ne left after s-processing has a large influence on the p-process via the {sup 22}Ne({alpha},n) reaction. We find that about 50% of p-nuclides are co-produced when normalized to their solar abundances in all adopted cases of seed distribution. Mo and Ru, which are largely underproduced in Type II supernovae (SNe II), are produced more than in SNe II although they are underproduced with respect to the yield levels of other p-nuclides. The ratios between p-nuclei and iron in the ejecta are larger than the solar ratios by a factor of 1.2. We also compare the yields of oxygen, iron, and p-nuclides in SNe Ia and SNe II and suggest that SNe Ia could make a larger contribution than SNe II to the solar system content of p-nuclei.

  1. The crossing statistic: dealing with unknown errors in the dispersion of Type Ia supernovae

    SciTech Connect (OSTI)

    Shafieloo, Arman; Clifton, Timothy; Ferreira, Pedro E-mail: tclifton@astro.ox.ac.uk

    2011-08-01

    We propose a new statistic that has been designed to be used in situations where the intrinsic dispersion of a data set is not well known: The Crossing Statistic. This statistic is in general less sensitive than χ{sup 2} to the intrinsic dispersion of the data, and hence allows us to make progress in distinguishing between different models using goodness of fit to the data even when the errors involved are poorly understood. The proposed statistic makes use of the shape and trends of a model's predictions in a quantifiable manner. It is applicable to a variety of circumstances, although we consider it to be especially well suited to the task of distinguishing between different cosmological models using type Ia supernovae. We show that this statistic can easily distinguish between different models in cases where the χ{sup 2} statistic fails. We also show that the last mode of the Crossing Statistic is identical to χ{sup 2}, so that it can be considered as a generalization of χ{sup 2}.

  2. FIRST EVIDENCE OF GLOBULAR CLUSTER FORMATION FROM THE EJECTA OF PROMPT TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Tsujimoto, Takuji [National Astronomical Observatory of Japan, Mitaka-shi, Tokyo 181-8588 (Japan); Bekki, Kenji, E-mail: taku.tsujimoto@nao.ac.jp [ICRAR, M468, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia)

    2012-06-01

    Recent spectroscopic observations of globular clusters (GCs) in the Large Magellanic Cloud (LMC) have discovered that one of the intermediate-age GCs, NGC 1718, with [Fe/H] = -0.7 has an extremely low [Mg/Fe] ratio of {approx}-0.9. We propose that NGC 1718 was formed from the ejecta of Type Ia supernovae mixed with very metal-poor ([Fe/H] <-1.3) gas about {approx}2 Gyr ago. The proposed scenario is shown to be consistent with the observed abundances of Fe-group elements such as Cr, Mn, and Ni. In addition, compelling evidence for asymptotic giant branch stars playing a role in chemical enrichment during this GC formation is found. We suggest that the origin of the metal-poor gas is closely associated with efficient gas transfer from the outer gas disk of the Small Magellanic Cloud to the LMC disk. We anticipate that the outer part of the LMC disk contains field stars exhibiting significantly low [Mg/Fe] ratios, formed through the same process as NGC 1718.

  3. REPORT NT-15-2

    National Nuclear Security Administration (NNSA)

    2 MAY 2015 OCCUPATIONAL RADIATION EXPOSURE FROM U.S. NAVAL NUCLEAR PLANTS AND THEIR SUPPORT FACILITIES NAVAL NUCLEAR PROPULSION PROGRAM DEPARTMENT OF THE NAVY WASHINGTON, D.C. ...

  4. UNITED STATES GOVERNIMI~NT

    Office of Legacy Management (LM)

    National Lead The property near Jacksonville, Florida, owned by the Compeny is operated by Humphreys Gold Corporation. I Moneeite, amounting to about 400 short tons per year is ...

  5. REPORT NT-14-2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    breathing for 40 hours per week throughout the year to reach an annual exposure to the lungs of one-tenth the Federal limit. Personnel are also trained to use respiratory...

  6. REPORT NT-14-3

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    hearing loss. This case is discussed further on page 54. As discussed above for the lungs, the basic Federal limit for radiation exposure to organs of the body from internal...

  7. WAR DEPARTaMMeNT

    Office of Legacy Management (LM)

    It is estixstad or:ly nsa apasifioatim billets will be extmdad ., during Pm-oh sad April. Yisld of haala from new billets is eatizatsd at S and ou old billets at-83. C'n this ...

  8. REPORT NT-14-1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of gamma radioactivity per milliliter, reactor coolant is not discharged to surrounding waters. Figure 1 shows a simplified block diagram of the 4 liquid processing system, which...

  9. REPORT NT-15-4

    National Nuclear Security Administration (NNSA)

    ... Trained personnel are available around the clock to respond to emergency situations and provide first-aid. * Extension of OSHOM Program to Subcontractor Employees: Subcontractors ...

  10. REPORT NT-15-3

    National Nuclear Security Administration (NNSA)

    ... the world's first full-scale nuclear power plant solely for the production of electricity. ... was the first reactor to prove that fuel breeding was possible in a water-cooled plant. ...

  11. Constraints on the progenitor system of the type Ia supernova 2014J from pre-explosion Hubble space telescope imaging

    SciTech Connect (OSTI)

    Kelly, Patrick L.; Fox, Ori D.; Filippenko, Alexei V.; Shen, Ken J.; Zheng, WeiKang; Graham, Melissa L.; Tucker, Brad E.; Cenko, S. Bradley; Schaefer, Gail

    2014-07-20

    We constrain the properties of the progenitor system of the highly reddened Type Ia supernova (SN Ia) 2014J in Messier 82 (M82; d ? 3.5 Mpc). We determine the supernova (SN) location using Keck-II K-band adaptive optics images, and we find no evidence for flux from a progenitor system in pre-explosion near-ultraviolet through near-infrared Hubble Space Telescope (HST) images. Our upper limits exclude systems having a bright red giant companion, including symbiotic novae with luminosities comparable to that of RS Ophiuchi. While the flux constraints are also inconsistent with predictions for comparatively cool He-donor systems (T ? 35,000 K), we cannot preclude a system similar to V445 Puppis. The progenitor constraints are robust across a wide range of R{sub V} and A{sub V} values, but significantly greater values than those inferred from the SN light curve and spectrum would yield proportionally brighter luminosity limits. The comparatively faint flux expected from a binary progenitor system consisting of white dwarf stars would not have been detected in the pre-explosion HST imaging. Infrared HST exposures yield more stringent constraints on the luminosities of very cool (T < 3000 K) companion stars than was possible in the case of SN Ia 2011fe.

  12. Metabolomic profiling of the nectars of Aquilegia pubescens and <i>A. Canadensis

    SciTech Connect (OSTI)

    Noutsos, Christos; Perera, Ann M.; Nikolau, Basil J.; Seaver, Samuel M. D.; Ware, Doreen H.; Motta, Andrea

    2015-05-01

    To date, variation in nectar chemistry of flowering plants has not been studied in detail. Such variation exerts considerable influence on pollinator–plant interactions, as well as on flower traits that play important roles in the selection of a plant for visitation by specific pollinators. Over the past 60 years the Aquilegia genus has been used as a key model for speciation studies. In this study, we defined the metabolomic profiles of flower samples of two Aquilegia species, <i>A. Canadensis and <i>A. pubescens. We identified a total of 75 metabolites that were classified into six main categories: organic acids, fatty acids, amino acids, esters, sugars, and unknowns. The mean abundances of 25 of these metabolites were significantly different between the two species, providing insights into interspecies variation in floral chemistry. Using the PlantSEED biochemistry database, we found that the majority of these metabolites are involved in biosynthetic pathways. Finally, we explored the annotated genome of <i>A. coerulea, using the PlantSEED pipeline and reconstructed the metabolic network of Aquilegia. This network, which contains the metabolic pathways involved in generating the observed chemical variation, is now publicly available from the DOE Systems Biology Knowledge Base (KBase; http://kbase.us).

  13. Spectroscopic Properties of Star-Forming Host Galaxies and Type Ia Supernova Hubble Residuals in a Nearly Unbiased Sample

    SciTech Connect (OSTI)

    D'Andrea, Chris B.; et al.

    2011-12-20

    We examine the correlation between supernova host galaxy properties and their residuals on the Hubble diagram. We use supernovae discovered during the Sloan Digital Sky Survey II - Supernova Survey, and focus on objects at a redshift of z < 0.15, where the selection effects of the survey are known to yield a complete Type Ia supernova sample. To minimize the bias in our analysis with respect to measured host-galaxy properties, spectra were obtained for nearly all hosts, spanning a range in magnitude of -23 < M_r < -17. In contrast to previous works that use photometric estimates of host mass as a proxy for global metallicity, we analyze host-galaxy spectra to obtain gas-phase metallicities and star-formation rates from host galaxies with active star formation. From a final sample of ~ 40 emission-line galaxies, we find that light-curve corrected Type Ia supernovae are ~ 0.1 magnitudes brighter in high-metallicity hosts than in low-metallicity hosts. We also find a significant (> 3{\\sigma}) correlation between the Hubble residuals of Type Ia supernovae and the specific star-formation rate of the host galaxy. We comment on the importance of supernova/host-galaxy correlations as a source of systematic bias in future deep supernova surveys.

  14. A POSSIBLE EVOLUTIONARY SCENARIO OF HIGHLY MAGNETIZED SUPER-CHANDRASEKHAR WHITE DWARFS: PROGENITORS OF PECULIAR TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Das, Upasana; Mukhopadhyay, Banibrata; Rao, A. R. E-mail: bm@physics.iisc.ernet.in

    2013-04-10

    Several recently discovered peculiar Type Ia supernovae seem to demand an altogether new formation theory that might help explain the puzzling dissimilarities between them and the standard Type Ia supernovae. The most striking aspect of the observational analysis is the necessity of invoking super-Chandrasekhar white dwarfs having masses {approx}2.1-2.8 M{sub Sun }, M{sub Sun} being the mass of Sun, as their most probable progenitors. Strongly magnetized white dwarfs having super-Chandrasekhar masses have already been established as potential candidates for the progenitors of peculiar Type Ia supernovae. Owing to the Landau quantization of the underlying electron degenerate gas, theoretical results yielded the observationally inferred mass range. Here, we sketch a possible evolutionary scenario by which super-Chandrasekhar white dwarfs could be formed by accretion on to a commonly observed magnetized white dwarf, invoking the phenomenon of flux freezing. This opens multiple possible evolution scenarios ending in supernova explosions of super-Chandrasekhar white dwarfs having masses within the range stated above. We point out that our proposal has observational support, such as the recent discovery of a large number of magnetized white dwarfs by the Sloan Digital Sky Survey.

  15. A=16Li (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Li (1993TI07) (Not illustrated) This nucleus has not been observed. Shell model studies (1988POZS) are used to predict J and the magnetic dipole moment....

  16. A=16He (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (Not illustrated) This nucleus has not been observed. See (1982AV1A, 1983ANZQ, 1986AJ04

  17. A=19Mg (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mg (1995TI07) (Not observed) See (1987AJ02) and (1987GU1K, 1987PO01, 1993HI08

  18. Radiogenic p-isotopes from type Ia supernova, nuclear physics uncertainties, and galactic chemical evolution compared with values in primitive meteorites

    SciTech Connect (OSTI)

    Travaglio, C.; Gallino, R.; Rauscher, T.; Dauphas, N.; Rpke, F. K.; Hillebrandt, W. E-mail: claudia.travaglio@b2fh.org

    2014-11-10

    The nucleosynthesis of proton-rich isotopes is calculated for multi-dimensional Chandrasekhar-mass models of Type Ia supernovae (SNe Ia) with different metallicities. The predicted abundances of the short-lived radioactive isotopes {sup 92}Nb, {sup 97,} {sup 98}Tc, and {sup 146}Sm are given in this framework. The abundance seeds are obtained by calculating s-process nucleosynthesis in the material accreted onto a carbon-oxygen white dwarf from a binary companion. A fine grid of s-seeds at different metallicities and {sup 13}C-pocket efficiencies is considered. A galactic chemical evolution model is used to predict the contribution of SN Ia to the solar system p-nuclei composition measured in meteorites. Nuclear physics uncertainties are critical to determine the role of SNe Ia in the production of {sup 92}Nb and {sup 146}Sm. We find that, if standard Chandrasekhar-mass SNe Ia are at least 50% of all SN Ia, they are strong candidates for reproducing the radiogenic p-process signature observed in meteorites.

  19. THE DETONATION MECHANISM OF THE PULSATIONALLY ASSISTED GRAVITATIONALLY CONFINED DETONATION MODEL OF Type Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Jordan, G. C. IV; Graziani, C.; Weide, K.; Norris, J.; Hudson, R.; Lamb, D. Q.; Fisher, R. T.; Townsley, D. M.; Meakin, C.; Reid, L. B.

    2012-11-01

    We describe the detonation mechanism composing the 'pulsationally assisted' gravitationally confined detonation (GCD) model of Type Ia supernovae. This model is analogous to the previous GCD model reported in Jordan et al.; however, the chosen initial conditions produce a substantively different detonation mechanism, resulting from a larger energy release during the deflagration phase. The resulting final kinetic energy and {sup 56}Ni yields conform better to observational values than is the case for the 'classical' GCD models. In the present class of models, the ignition of a deflagration phase leads to a rising, burning plume of ash. The ash breaks out of the surface of the white dwarf, flows laterally around the star, and converges on the collision region at the antipodal point from where it broke out. The amount of energy released during the deflagration phase is enough to cause the star to rapidly expand, so that when the ash reaches the antipodal point, the surface density is too low to initiate a detonation. Instead, as the ash flows into the collision region (while mixing with surface fuel), the star reaches its maximally expanded state and then contracts. The stellar contraction acts to increase the density of the star, including the density in the collision region. This both raises the temperature and density of the fuel-ash mixture in the collision region and ultimately leads to thermodynamic conditions that are necessary for the Zel'dovich gradient mechanism to produce a detonation. We demonstrate feasibility of this scenario with three three-dimensional (3D), full star simulations of this model using the FLASH code. We characterized the simulations by the energy released during the deflagration phase, which ranged from 38% to 78% of the white dwarf's binding energy. We show that the necessary conditions for detonation are achieved in all three of the models.

  20. Persistent C II absorption in the normal type Ia supernova 2002fk

    SciTech Connect (OSTI)

    Cartier, Rgis; Zelaya, Paula [Millennium Institute of Astrophysics, Casilla 36-D, Santiago (Chile); Hamuy, Mario; Maza, Jos; Gonzlez, Luis; Huerta, Leonor [Departamento de Astronoma, Universidad de Chile, Casilla 36-D, Santiago (Chile); Pignata, Giuliano [Departamento Ciencias Fisicas, Universidad Andres Bello, Av. Repblica 252, Santiago (Chile); Frster, Francisco [Center for Mathematical Modelling, Universidad de Chile, Avenida Blanco Encalada 2120, Piso 7, Santiago (Chile); Folatelli, Gaston [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Phillips, Mark M.; Morrell, Nidia; Contreras, Carlos; Roth, Miguel; Gonzlez, Sergio [Carnegie Institution of Washington, Las Campanas Observatory, Colina el Pino s/n, Casilla 601 (Chile); Krisciunas, Kevin; Suntzeff, Nicholas B. [Department of Physics and Astronomy, Texas A and M University, 4242 TAMU, College Station, TX 77843 (United States); Clocchiatti, Alejandro [Departamento de Astronoma y Astrofsica, Pontificia Universidad Catlica de Chile, Casilla 306, Santiago (Chile); Coppi, Paolo [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States); Koviak, Kathleen, E-mail: rcartier@das.uchile.cl [Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 911901 (United States)

    2014-07-01

    We present well-sampled UBVRIJHK photometry of SN 2002fk starting 12 days before maximum light through 122 days after peak brightness, along with a series of 15 optical spectra from 4 to +95 days since maximum. Our observations show the presence of C II lines in the early-time spectra of SN 2002fk, expanding at 11,000 km s{sup 1} and persisting until 8 days past maximum light with a velocity of ?9000 km s{sup 1}. SN 2002fk is characterized by a small velocity gradient of v-dot {sub Si} {sub II}=26 km s{sup 1} day{sup 1}, possibly caused by an off-center explosion with the ignition region oriented toward the observer. The connection between the viewing angle of an off-center explosion and the presence of C II in the early-time spectrum suggests that the observation of C II could be also due to a viewing angle effect. Adopting the Cepheid distance to NGC 1309 we provide the first H {sub 0} value based on near-infrared (near-IR) measurements of a Type Ia supernova (SN) between 63.0 0.8 (3.4 systematic) and 66.7 1.0 (3.5 systematic) km s{sup 1} Mpc{sup 1}, depending on the absolute magnitude/decline rate relationship adopted. It appears that the near-IR yields somewhat lower (6%-9%) H {sub 0} values than the optical. It is essential to further examine this issue by (1) expanding the sample of high-quality near-IR light curves of SNe in the Hubble flow, and (2) increasing the number of nearby SNe with near-IR SN light curves and precise Cepheid distances, which affords the promise to deliver a more precise determination of H {sub 0}.

  1. MID-IR SPECTRA OF TYPE Ia SN 2014J IN M82 SPANNING THE FIRST 4 MONTHS

    SciTech Connect (OSTI)

    Telesco, Charles M.; Li, Dan; Barnes, Peter J.; Mariñas, Naibí; Zhang, Han; Höflich, Peter; Álvarez, Carlos; Fernández, Sergio; Rebolo, Rafael; Hough, James H.; Levenson, N. A.; Pantin, Eric; Roche, Patrick E-mail: phoeflich77@gmail.com

    2015-01-10

    We present a time series of 8-13 μm spectra and photometry for SN 2014J obtained 57, 81, 108, and 137 days after the explosion using CanariCam on the Gran Telescopio Canarias. This is the first mid-IR time series ever obtained for a Type Ia supernova (SN Ia). These observations can be understood within the framework of the delayed detonation model and the production of ∼0.6 M {sub ☉} of {sup 56}Ni, consistent with the observed brightness, the brightness decline relation, and the γ-ray fluxes. The [Co III] line at 11.888 μm is particularly useful for evaluating the time evolution of the photosphere and measuring the amount of {sup 56}Ni and thus the mass of the ejecta. Late-time line profiles of SN 2014J are rather symmetric and not shifted in the rest frame. We see argon emission, which provides a unique probe of mixing in the transition layer between incomplete burning and nuclear statistical equilibrium. We may see [Fe III] and [Ni IV] emission, both of which are observed to be substantially stronger than indicated by our models. If the latter identification is correct, then we are likely observing stable Ni, which might imply central mixing. In addition, electron capture, also required for stable Ni, requires densities larger than ∼1 × 10{sup 9} g cm{sup –3}, which are expected to be present only in white dwarfs close to the Chandrasekhar limit. This study demonstrates that mid-IR studies of SNe Ia are feasible from the ground and provide unique information, but it also indicates the need for better atomic data.

  2. Systematic uncertainties associated with the cosmological analysis of the first Pan-STARRS1 type Ia supernova sample

    SciTech Connect (OSTI)

    Scolnic, D.; Riess, A.; Brout, D.; Rodney, S. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Huber, M. E.; Tonry, J. L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Foley, R. J.; Chornock, R.; Berger, E.; Soderberg, A. M.; Stubbs, C. W.; Kirshner, R. P.; Challis, P.; Czekala, I.; Drout, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Narayan, G. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Smartt, S. J.; Botticella, M. T. [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Schlafly, E. [Max Planck Institute for Astronomy, Konigstuhl 17, D-69117 Heidelberg (Germany); and others

    2014-11-01

    We probe the systematic uncertainties from the 113 Type Ia supernovae (SN Ia) in the Pan-STARRS1 (PS1) sample along with 197 SN Ia from a combination of low-redshift surveys. The companion paper by Rest et al. describes the photometric measurements and cosmological inferences from the PS1 sample. The largest systematic uncertainty stems from the photometric calibration of the PS1 and low-z samples. We increase the sample of observed Calspec standards from 7 to 10 used to define the PS1 calibration system. The PS1 and SDSS-II calibration systems are compared and discrepancies up to ?0.02 mag are recovered. We find uncertainties in the proper way to treat intrinsic colors and reddening produce differences in the recovered value of w up to 3%. We estimate masses of host galaxies of PS1 supernovae and detect an insignificant difference in distance residuals of the full sample of 0.037 0.031 mag for host galaxies with high and low masses. Assuming flatness and including systematic uncertainties in our analysis of only SNe measurements, we find w =?1.120{sub ?0.206}{sup +0.360}(Stat){sub ?0.291}{sup +0.269}(Sys). With additional constraints from Baryon acoustic oscillation, cosmic microwave background (CMB) (Planck) and H {sub 0} measurements, we find w=?1.166{sub ?0.069}{sup +0.072} and ?{sub m}=0.280{sub ?0.012}{sup +0.013} (statistical and systematic errors added in quadrature). The significance of the inconsistency with w = 1 depends on whether we use Planck or Wilkinson Microwave Anisotropy Probe measurements of the CMB: w{sub BAO+H0+SN+WMAP}=?1.124{sub ?0.065}{sup +0.083}.

  3. Nearby Supernova Factory Observations of SN 2005gj: Another TypeIa Supernova in a Massive Circumstellar Envelope

    SciTech Connect (OSTI)

    Aldering, G.; Antilogus, P.; Bailey, S.; Baltay, C.; Bauer, A.; Blanc, N.; Bongard, S.; Copin, Y.; Gangler, E.; Gilles, S.; Kessler, R.; Kocevski, D.; Lee, B.C.; Loken, S.; Nugent, P.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigaudier, G.; Scalzo, R.; Smadja, G.; Thomas, R.C.; Wang, L.; Weaver, B.A.; Rabinowitz, D.; Bauer, A.

    2006-06-01

    We report the independent discovery and follow-up observations of supernova 2005gj by the Nearby Supernova Factory. This is the second confirmed case of a ''hybrid'' Type Ia/IIn supernova, which like the prototype SN 2002ic, we interpret as the explosion of a white dwarf interacting with a circumstellar medium. Our early-phase photometry of SN 2005gj shows that the strength of the interaction between the supernova ejecta and circumstellar material is much stronger than for SN 2002ic. Our .rst spectrum shows a hot continuum with broad and narrow H{alpha} emission. Later spectra, spanning over 4 months from outburst, show clear Type Ia features combined with broad and narrow H{gamma}, H{beta},H{alpha} and He I {lambda}{lambda}5876,7065 in emission. At higher resolution, P Cygni profiles are apparent. Surprisingly, we also observe an inverted P Cygni profile for [O III] {lambda}5007. We find that the lightcurve and measured velocity of the unshocked circumstellar material imply mass loss as recently as 8 years ago. This is in contrast to SN 2002ic, for which an inner cavity in the circumstellar material was inferred. Within the context of the thin-shell approximation, the early lightcurve is well-described by a flat radial density profile for the circumstellar material. However, our decomposition of the spectra into Type Ia and shock emission components allows for little obscuration of the supernova, suggesting an aspherical or clumpy distribution for the circumstellar material. We suggest that the emission line velocity profiles arise from electron scattering rather than the kinematics of the shock. This is supported by the inferred high densities, and the lack of evidence for evolution in the line widths. Ground- and space-based photometry, and Keck spectroscopy, of the host galaxy are used to ascertain that the host galaxy has low metallicity (Z/Z{sub {circle_dot}} < 0.3; 95% confidence) and that this galaxy is undergoing a significant star formation event that

  4. DISPLAYING THE HETEROGENEITY OF THE SN 2002cx-LIKE SUBCLASS OF TYPE Ia SUPERNOVAE WITH OBSERVATIONS OF THE Pan-STARRS-1 DISCOVERED SN 2009ku

    SciTech Connect (OSTI)

    Narayan, G.; Foley, R. J.; Berger, E.; Chornock, R.; Rest, A.; Soderberg, A. M.; Kirshner, R. P.; Botticella, M. T.; Smartt, S.; Valenti, S.; Huber, M. E.; Scolnic, D.; Grav, T.; Burgett, W. S.; Chambers, K. C.; Flewelling, H. A.; Gates, G.; Kaiser, N.; Magnier, E. A.; Morgan, J. S. E-mail: rfoley@cfa.harvard.edu

    2011-04-10

    SN 2009ku, discovered by Pan-STARRS-1, is a Type Ia supernova (SN Ia), and a member of the distinct SN 2002cx-like class of SNe Ia. Its light curves are similar to the prototypical SN 2002cx, but are slightly broader and have a later rise to maximum in g. SN 2009ku is brighter ({approx}0.6 mag) than other SN 2002cx-like objects, peaking at M{sub V} = -18.4 mag, which is still significantly fainter than typical SNe Ia. SN 2009ku, which had an ejecta velocity of {approx}2000 km s{sup -1} at 18 days after maximum brightness, is spectroscopically most similar to SN 2008ha, which also had extremely low-velocity ejecta. However, SN 2008ha had an exceedingly low luminosity, peaking at M{sub V} = -14.2 mag, {approx}4 mag fainter than SN 2009ku. The contrast of high luminosity and low ejecta velocity for SN 2009ku is contrary to an emerging trend seen for the SN 2002cx class. SN 2009ku is a counterexample of a previously held belief that the class was more homogeneous than typical SNe Ia, indicating that the class has a diverse progenitor population and/or complicated explosion physics. As the first example of a member of this class of objects from the new generation of transient surveys, SN 2009ku is an indication of the potential for these surveys to find rare and interesting objects.

  5. The permeation behavior of deuterium through 1Cr18Ni9Ti stainless steel with TiN+TiC-TiN multiple films

    SciTech Connect (OSTI)

    Xiong, Y.; Song, J.; Luo, D.; Lei, Q.; Chen, C.

    2015-03-15

    The prevention of tritium losses via permeation through structure components is an important issue in fusion technology. The production of thin layers on materials with low diffusivity and/or low surface recombination constants (so-called permeation barriers) seems to be the most practical method to reduce or hinder the permeation of tritium through materials. TiN+TiC+TiN multiple films are deposited on the surface of 1Cr18Ni9Ti stainless steel by ion-beam assisted deposition technology. The characteristics of films are tested by XPS ASEM and XRD, which shows that the film are compact and uniform with a thickness of about 15 μm, and have a good adherence with the substrate below 773 K. The diffraction peaks in the XRD patterns for TiC and TiN are broadened, implying that the multiple films are deposited on the surface of 1Cr18Ni9Ti stainless steel. Meanwhile, the C-H bonded CH{sub 4}-appears in the infrared spectra of multiple films, suggesting that the CH{sub 4}- is in a static state, so hydrogen atom cannot migrate from the site bonded with carbon to a neighboring site. The measured deuterium permeability in 1Cr18Ni9Ti stainless steel coated with multiple films is 2-3 orders of magnitude lower than that of pure 1Cr18Ni9Ti stainless steel substrate from 473 K to 773 K. However, this barrier is partly destroyed above 773 K.

  6. Ti Leggett | Argonne Leadership Computing Facility

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ti Leggett Deputy Project Directcor & Deputy Director of Operations Argonne National Laboratory 9700 S. Cass Avenue Building 240 - Room 3132 Argonne, IL 60439 630-252-1937 tleggett

  7. A=10C (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 10C) GENERAL: References to articles on general properties of 10C published since the previous review (1988AJ01) are grouped into...

  8. A=10N (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (Not illustrated) GENERAL: References to articles on general properties of 10N published since the previous review (1988AJ01) are grouped into categories and listed,...

  9. A=10Li (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 10Li) GENERAL: References to articles on general properties of 10Li published since the previous review (1988AJ01) are grouped into...

  10. A=10He (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 10He) GENERAL: References to articles on general properties of 10He published since the previous review (1988AJ01) are grouped into...

  11. A=18Li (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Li (1995TI07) (Not illustrated) 18Li has not been observed. Shell model calculations described in (1988POZS) predict the ground-state magentic dipole moment and charge and matter radii.

  12. A=18Mg, etc. (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (Not observed) See (1986AN07) and (1983ANZQ). See also the results of calculations of β+/electron capture half lives for neutron deficient nuclei in (1993HI08

  13. A=6B (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (Not illustrated) Not observed: see ( 1984AJ01, 1989GR06 [6Li(π+, π-) at Eπ+ = 180, 240 MeV], 1993PO11 [properties of exotic light nuclei]) (1998SU18

  14. A=6C (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (Not illustrated) Not observed: see (1979AJ01, 1984AJ01, 1989GR06 [6Li(π+, π-) at Eπ+ = 180, 240 MeV], 1993PO11 [properties of exotic light nuclei]) (1998SU18

  15. A=20B (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    98TI06) (Not observed) The mass excess of 20B is predicted to be 69.08 MeV (1974TH01). 20B is then unstable with respect to breakup into 19B + n by 0.9 MeV: see 19B in (1995TI07) and (1978AJ03, 1983ANZQ) and see the work on effective interactions for the (0p1s0d) nuclear shell-model space (1992WA22

  16. Instability of Hydrogenated TiO2

    SciTech Connect (OSTI)

    Nandasiri, Manjula I.; Shutthanandan, V.; Manandhar, Sandeep; Schwarz, Ashleigh M.; Oxenford, Lucas S.; Kennedy, John V.; Thevuthasan, Suntharampillai; Henderson, Michael A.

    2015-11-06

    Hydrogenated TiO2 (H-TiO2) is toted as a viable visible light photocatalyst. We report a systematic study on the thermal stability of H-implanted TiO2 using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Protons (40 keV) implanted at a ~2 atom % level within a ~120 nm wide profile of rutile TiO2(110) were situated ~300 nm below the surface. NRA revealed that this H-profile broadened preferentially toward the surface after annealing at 373 K, dissipated out of the crystal into vacuum at 473 K, and was absent within the beam sampling depth (~800 nm) at 523 K. Photoemission showed that the surface was reduced in concert with these changes. Similar anneals had no effect on pristine TiO2(110). The facile bulk diffusivity of H in rutile, as well as its activity toward interfacial reduction, significantly limits the utilization of H-TiO2 as a photocatalyst. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. The research was performed using the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

  17. A Chandrasekhar mass progenitor for the Type Ia supernova remnant 3C 397 from the enhanced abundances of nickel and manganese

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yamaguchi, Hiroya; Badenes, Carles; Foster, Adam R.; Bravo, Eduardo; Williams, Brian J.; Maeda, Keiichi; Nobukawa, Masayoshi; Eriksen, Kristoffer A.; Brickhouse, Nancy S.; Petre, Robert; et al

    2015-03-12

    Despite decades of intense efforts, many fundamental aspects of Type Ia supernovae (SNe Ia) remain elusive. One of the major open questions is whether the mass of an exploding white dwarf (WD) is close to the Chandrasekhar limit. Here, we report the detection of strong K-shell emission from stable Fe-peak elements in the Suzaku X-ray spectrum of the Type Ia supernova remnant (SNR) 3C 397. The high Ni/Fe and Mn/Fe mass ratios (0.11–0.24 and 0.018–0.033, respectively) in the hot plasma component that dominates the K-shell emission lines indicate a degree of neutronization in the supernova ejecta that can only bemore » achieved by electron capture in the dense cores of exploding WDs with a near-Chandrasekhar mass. This suggests a single-degenerate origin for 3C 397, since Chandrasekhar mass progenitors are expected naturally if the WD accretes mass slowly from a companion. Altogether with other results supporting the double-degenerate scenario, our work adds to the mounting evidence that both progenitor channels make a significant contribution to the SN Ia rate in star-forming galaxies.« less

  18. A Chandrasekhar mass progenitor for the Type Ia supernova remnant 3C 397 from the enhanced abundances of nickel and manganese

    SciTech Connect (OSTI)

    Yamaguchi, Hiroya; Badenes, Carles; Foster, Adam R.; Bravo, Eduardo; Williams, Brian J.; Maeda, Keiichi; Nobukawa, Masayoshi; Eriksen, Kristoffer A.; Brickhouse, Nancy S.; Petre, Robert; Koyama, Katsuji

    2015-03-12

    Despite decades of intense efforts, many fundamental aspects of Type Ia supernovae (SNe Ia) remain elusive. One of the major open questions is whether the mass of an exploding white dwarf (WD) is close to the Chandrasekhar limit. Here, we report the detection of strong K-shell emission from stable Fe-peak elements in the Suzaku X-ray spectrum of the Type Ia supernova remnant (SNR) 3C 397. The high Ni/Fe and Mn/Fe mass ratios (0.11–0.24 and 0.018–0.033, respectively) in the hot plasma component that dominates the K-shell emission lines indicate a degree of neutronization in the supernova ejecta that can only be achieved by electron capture in the dense cores of exploding WDs with a near-Chandrasekhar mass. This suggests a single-degenerate origin for 3C 397, since Chandrasekhar mass progenitors are expected naturally if the WD accretes mass slowly from a companion. Altogether with other results supporting the double-degenerate scenario, our work adds to the mounting evidence that both progenitor channels make a significant contribution to the SN Ia rate in star-forming galaxies.

  19. Morphology, deformation, and defect structures of TiCr{sub 2} in Ti-Cr alloys

    SciTech Connect (OSTI)

    Chen, K.C.; Allen, S.M.; Livingston, J.D.

    1992-12-31

    The morphologies and defect structures of TiCr{sub 2} in several Ti-Cr alloys have been examined by optical metallography, x-ray diffraction, and transmission electron microscopy (TEM), in order to explore the room-temperature deformability of the Laves phase TiCr{sub 2}. The morphology of the Laves phase was found to be dependent upon alloy composition and annealing temperature. Samples deformed by compression have also been studied using TEM. Comparisons of microstructures before and after deformation suggest an increase in twin, stacking fault, and dislocation density within the Laves phase, indicating some but not extensive room-temperature deformability.

  20. Solution-Derived Bi(ZnTi)O3 - BaTiO3 Thin Films with Bulk-like...

    Office of Scientific and Technical Information (OSTI)

    Title: Solution-Derived Bi(ZnTi)O3 - BaTiO3 Thin Films with Bulk-like Permittivity. Abstract not provided. Authors: Meyer, Kelsey Elizabeth ; Kotula, Paul Gabriel ; Brennecka, ...

  1. Carrier-Controlled Ferromagnetism in SrTiO3

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Moetakef, Pouya; Williams, James R.; Ouellette, Daniel G.; Kajdos, Adam P.; Goldhaber-Gordon, David; Allen, S. James; Stemmer, Susanne

    2012-06-27

    Magnetotransport and superconducting properties are investigated for uniformly La-doped SrTiO3 films and GdTiO3/SrTiO3 heterostructures, respectively. GdTiO3/SrTiO3 interfaces exhibit a high-density 2D electron gas on the SrTiO3 side of the interface, while, for the SrTiO3 films, carriers are provided by the dopant atoms. Both types of samples exhibit ferromagnetism at low temperatures, as evidenced by a hysteresis in the magnetoresistance. For the uniformly doped SrTiO3 films, the Curie temperature is found to increase with doping and to coexist with superconductivity for carrier concentrations on the high-density side of the superconducting dome. The Curie temperature of the GdTiO3/SrTiO3 heterostructures scales with themore » thickness of the SrTiO3 quantum well. The results are used to construct a stability diagram for the ferromagnetic and superconducting phases of SrTiO3.« less

  2. A=18C (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of the 48Ca(18O, 18C)48Ti reaction. 18C is then bound by 4.188 MeV with respect to breakup into 17C + n. See also (1982FI10, 1987AJ02, 1992WA22). 1. 18C(-)18N Qm 11.807 The...

  3. A=18Na (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (Not observed) 18Na has not been observed; its atomic mass excess has been estimated to be 25.32 MeV (1993AU05); it is then unbound with respect to proton emission by 1.6 MeV: see (1978AJ03). See also (1986AN07) and (1983ANZQ

  4. A=5Be (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (See the Isobar Diagram for 5Be) See also the A = 5 introductory discussion titled A = 5 resonance parameters. The absence of any group structure in the neutron spectrum in the reaction 3He(3He, n)5Be at E(3He) = 18.0 to 26.0 MeV indicates that 5Beg.s

  5. Cosmological constraints from measurements of type Ia supernovae discovered during the first 1.5 yr of the Pan-STARRS1 survey

    SciTech Connect (OSTI)

    Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Scolnic, D.; Riess, A.; Rodney, S.; Brout, D. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Foley, R. J.; Chornock, R.; Berger, E.; Soderberg, A. M.; Stubbs, C. W.; Kirshner, R. P.; Challis, P.; Czekala, I.; Drout, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Huber, M. E.; Tonry, J. L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Narayan, G. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Smartt, S. J. [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT71NN (United Kingdom); Schlafly, E. [Max Planck Institute for Astronomy, Knigstuhl 17, D-69117 Heidelberg (Germany); Botticella, M. T. [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); and others

    2014-11-01

    We present griz {sub P1} light curves of 146 spectroscopically confirmed Type Ia supernovae (SNe Ia; 0.03 < z < 0.65) discovered during the first 1.5 yr of the Pan-STARRS1 Medium Deep Survey. The Pan-STARRS1 natural photometric system is determined by a combination of on-site measurements of the instrument response function and observations of spectrophotometric standard stars. We find that the systematic uncertainties in the photometric system are currently 1.2% without accounting for the uncertainty in the Hubble Space Telescope Calspec definition of the AB system. A Hubble diagram is constructed with a subset of 113 out of 146 SNe Ia that pass our light curve quality cuts. The cosmological fit to 310 SNe Ia (113 PS1 SNe Ia + 222 light curves from 197 low-z SNe Ia), using only supernovae (SNe) and assuming a constant dark energy equation of state and flatness, yields w=?1.120{sub ?0.206}{sup +0.360}(Stat){sub ?0.291}{sup +0.269}(Sys). When combined with BAO+CMB(Planck)+H {sub 0}, the analysis yields ?{sub M}=0.280{sub ?0.012}{sup +0.013} and w=?1.166{sub ?0.069}{sup +0.072} including all identified systematics. The value of w is inconsistent with the cosmological constant value of 1 at the 2.3? level. Tension endures after removing either the baryon acoustic oscillation (BAO) or the H {sub 0} constraint, though it is strongest when including the H {sub 0} constraint. If we include WMAP9 cosmic microwave background (CMB) constraints instead of those from Planck, we find w=?1.124{sub ?0.065}{sup +0.083}, which diminishes the discord to <2?. We cannot conclude whether the tension with flat ?CDM is a feature of dark energy, new physics, or a combination of chance and systematic errors. The full Pan-STARRS1 SN sample with ?three times as many SNe should provide more conclusive results.

  6. The corrosivity and passivity of sputtered Mg-Ti alloys

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Song, Guang -Ling; Unocic, Kinga A.; Meyer, III, Harry M.; Cakmak, Ercan; Brady, Michael P.; Gannon, Paul E.; Himmer, Phil; Andrews, Quinn

    2015-11-30

    Our study explored the possibility of forming a “stainless” Mg–Ti alloy. The electrochemical behavior of magnetron-sputtered Mg–Ti alloys was measured in a NaCl solution, and the surface films on the alloys were examined by XPS, SEM and TEM. Increased corrosion resistance was observed with increased Ti content in the sputtered Mg–Ti alloys, but passive-like behavior was not reached until the Ti level (atomic %) was higher than the Mg level. Moreover, the surface film that formed on sputtered Mg–Ti based alloys in NaCl solution was thick, discontinuous and non-protective, whereas a thin, continuous and protective Mg and Ti oxide filmmore » was formed on a sputtered Ti–Mg based alloy.« less

  7. The corrosivity and passivity of sputtered Mg-Ti alloys

    SciTech Connect (OSTI)

    Song, Guang -Ling; Unocic, Kinga A.; Meyer, III, Harry M.; Cakmak, Ercan; Brady, Michael P.; Gannon, Paul E.; Himmer, Phil; Andrews, Quinn

    2015-11-30

    Our study explored the possibility of forming a “stainless” Mg–Ti alloy. The electrochemical behavior of magnetron-sputtered Mg–Ti alloys was measured in a NaCl solution, and the surface films on the alloys were examined by XPS, SEM and TEM. Increased corrosion resistance was observed with increased Ti content in the sputtered Mg–Ti alloys, but passive-like behavior was not reached until the Ti level (atomic %) was higher than the Mg level. Moreover, the surface film that formed on sputtered Mg–Ti based alloys in NaCl solution was thick, discontinuous and non-protective, whereas a thin, continuous and protective Mg and Ti oxide film was formed on a sputtered Ti–Mg based alloy.

  8. Effect of neutron irradiation on defect evolution in Ti3SiC2 and Ti2AlC

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tallman, Darin J.; He, Lingfeng; Garcia-Diaz, Brenda L.; Hoffman, Elizabeth N.; Kohse, Gordon; Sindelar, Robert L.; Barsoum, Michel W.

    2015-10-23

    Here, we report on the characterization of defects formed in polycrystalline Ti3SiC2 and Ti2AlC samples exposed to neutron irradiation – up to 0.1 displacements per atom (dpa) at 350 ± 40 °C or 695 ± 25 °C, and up to 0.4 dpa at 350 ± 40 °C. Black spots are observed in both Ti3SiC2 and Ti2AlC after irradiation to both 0.1 and 0.4 dpa at 350 °C. After irradiation to 0.1 dpa at 695 °C, small basal dislocation loops, with a Burgers vector of b = 1/2 [0001] are observed in both materials. At 9 ± 3 and 10 ±more » 5 nm, the loop diameters in the Ti3SiC2 and Ti2AlC samples, respectively, were comparable. At 1 × 1023 loops/m3, the dislocation loop density in Ti2AlC was ≈1.5 orders of magnitude greater than in Ti3SiC2, at 3 x 1021 loops/m3. After irradiation at 350 °C, extensive microcracking was observed in Ti2AlC, but not in Ti3SiC2. The room temperature electrical resistivities increased as a function of neutron dose for all samples tested, and appear to saturate in the case of Ti3SiC2. The MAX phases are unequivocally more neutron radiation tolerant than the impurity phases TiC and Al2O3. Based on these results, Ti3SiC2 appears to be a more promising MAX phase candidate for high temperature nuclear applications than Ti2AlC.« less

  9. No X-rays from the very nearby type Ia SN 2014J: Constraints on its environment

    SciTech Connect (OSTI)

    Margutti, R.; Parrent, J.; Kamble, A.; Soderberg, A. M.; Milisavljevic, D.; Drout, M. R.; Kirshner, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Foley, R. J. [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801 (United States)

    2014-07-20

    Deep X-ray observations of the post-explosion environment around the very nearby Type Ia SN 2014J (d{sub L} = 3.5 Mpc) reveal no X-ray emission down to a luminosity L{sub x} < 7 10{sup 36} erg s{sup 1} (0.3-10 keV) at ?t ? 20 days after the explosion. We interpret this limit in the context of inverse Compton emission from upscattered optical photons by the supernova shock and constrain the pre-explosion mass-loss rate of the stellar progenitor system to be M-dot <10{sup ?9} M{sub ?} yr{sup ?1} (for wind velocity v{sub w} = 100 km s{sup 1}). Alternatively, the SN shock might be expanding into a uniform medium with density n{sub CSM} < 3 cm{sup 3}. These results rule out single-degenerate (SD) systems with steady mass loss until the terminal explosion and constrain the fraction of transferred material lost at the outer Lagrangian point to be ?1%. The allowed progenitors are (1) white dwarf-white dwarf progenitors, (2) SD systems with unstable hydrogen burning experiencing recurrent nova eruptions with recurrence time t < 300 yr, and (3) stars where the mass loss ceases before the explosion.

  10. ASYMMETRY IN THE OBSERVED METAL-RICH EJECTA OF THE GALACTIC TYPE IA SUPERNOVA REMNANT G299.22.9

    SciTech Connect (OSTI)

    Post, Seth; Park, Sangwook [Department of Physics, University of Texas at Arlington, Arlington, Box 19059, TX 76019 (United States); Badenes, Carles [Department of Physics and Astronomy and Pittsburgh Particle Physics, Astrophysics, and Cosmology Center (PITT-PACC), University of Pittsburgh, 3941 OHara Street, Pittsburgh, PA 15260 (United States); Burrows, David N. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Hughes, John P. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019 (United States); Lee, Jae-Joon [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Mori, Koji [Department of Applied Physics, University of Miyazaki, 1-1 Gakuen Kibana-dai Nishi, Miyazaki 889-2192 (Japan); Slane, Patrick O., E-mail: seth.post@mavs.uta.edu, E-mail: badenes@pitt.edu, E-mail: burrows@astro.psu.edu, E-mail: jph@physics.rutgers.edu, E-mail: mori@astro.miyazaki-u.ac.jp, E-mail: slane@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2014-09-01

    We have performed a deep Chandra observation of the Galactic TypeIa supernova remnant G299.22.9. Here we report the initial results from our imaging and spectral analysis. The observed abundance ratios of the central ejecta are in good agreement with those predicted by delayed-detonation TypeIa supernovae models. We reveal inhomogeneous spatial and spectral structures of metal-rich ejecta in G299.22.9. The Fe/Si abundance ratio in the northern part of the central ejecta region is higher than that in the southern part. A significant continuous elongation of ejecta material extends out to the western outermost boundary of the remnant. In this western elongation, both the Si and Fe are enriched with a similar abundance ratio to that in the southern part of the central ejecta region. These structured distributions of metal-rich ejecta material suggest that this TypeIa supernova might have undergone a significantly asymmetric explosion and/or has been expanding into a structured medium.

  11. Structural and Morphological Difference Between Ti/TiN/TiCN Coatings Grown in Multilayer and Graded Form

    SciTech Connect (OSTI)

    Restrepo, E.; Baena, A.; Agudelo, C.; Castillo, H.; Devia, A.; Marino, A.

    2006-12-04

    Thin films can be grown in super-lattice, multilayers and graded form, having each one advantages and disadvantages. The difference between multilayer and graded coatings is the interface. In multilayers the interface is abrupt and in graded coatings it is diffuse. The interface influences many chemical and physical properties of the materials, and its choice depends on the application. Graded coatings have the advantage of having gradual properties such as thermal expansion coefficient and lattice parameter, avoiding adherence problems due to good match between their component materials. In this work the comparison between some properties of coatings grown as multilayer and graded is performed. The materials are produced using the sputtering DC technique because of its facility to control the deposition parameters and generate a slow growth. The target is a disc of titanium and the samples are made of stainless steel 304. The working gases are argon, nitrogen and methane, which are mixed according to the material to be produced, i.e. Ti layer is grown with argon, the TiN film is produced with a mixture of argon and nitrogen, and the TiCN material is obtained mixing argon, nitrogen and methane. These materials are characterized with AFM in order to determine grain size and with XPS studying the chemical composition and performing depth profiles.

  12. A=3n (1987TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1987TI07) (Not illustrated) GENERAL: The weight of experimental evidence reviewed in the previous compilation of Fiarman and Hanna (1975FI08) is strongly against the existence of a bound state of the three-neutron system, and only controversial evidence of 3n resonances was cited. Several experiments carried out more recently have strengthened the evidence against the bound trineutron and have failed to discover resonance structure that cannot be otherwise explained. The most suggestive work is

  13. A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

    SciTech Connect (OSTI)

    F. Hua; K. Mon; P. Pasupathi; G. Gordon

    2004-05-11

    Titanium alloy degradation modes are reviewed in relation to their performance in repository environments. General corrosion, localized corrosion, stress corrosion cracking, hydrogen induced cracking, microbially influenced corrosion, and radiation-assisted corrosion of Ti alloys are considered. With respect to the Ti Grade 7 drip shields selected for emplacement in the repository at Yucca Mountain, general corrosion, hydrogen induced cracking, and radiation-assisted corrosion will not lead to failure within the 10,000 year regulatory period; stress corrosion cracking (in the absence of disruptive events) is of no consequence to barrier performance; and localized corrosion and microbially influenced corrosion are not expected to occur. To facilitate the discussion, Ti Grades 2, 5, 7, 9, 11, 12, 16, 17, 18, and 24 are included in this review.

  14. Nature of Transactions (TI) Code | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    | (NNSA) Nature of Transactions (TI) Code U.S. Department of Energy / U.S. Nuclear Regulatory Commission Nuclear Materials Management & Safeguards System Nature of Transactions (TI) Code* Nature of Transactions (TI) Code* Code: Description: A Initiates lease and financial responsibility of DOE-owned material B Transfer of lease and financial responsiblity of DOE-owned material C Transfer of DOE-owned material with no change in lease or financial responsibility D Return to DOE for credit

  15. Thermoelastic Analysis of a Vibrating TiB/Ti Cantilever Beam Using Differential Thermography

    SciTech Connect (OSTI)

    Byrd, Larry; Wyen, Travis; Byrd, Alex

    2008-02-15

    Differential thermography has been used to detect the fluctuating temperatures due the thermoelastic effect for a number of years. This paper examines functionally graded TiB/Ti cantilever beams excited on an electromechanical shaker in fully reversed bending. Finite difference analysis of specimens was used to look at the effect of heat conduction, convection and the fundamental frequency on the surface temperature distribution and compared to experimental data. The thermoelastic effect was also used to detect cracking and the stress field at the tip of the fixture during fatigue.

  16. Ab initio Study of He Stability in hcp-Ti

    SciTech Connect (OSTI)

    Dai, Yunya; Yang, Li; Peng, SM; Long, XG; Gao, Fei; Zu, Xiaotao T.

    2010-12-20

    The stability of He in hcp-Ti was studied using ab initio method based on density functional theory. The results indicate that a single He atom prefers to occupy the tetrahedral site rather than the octahedral site. The interaction of He defects with Ti atoms has been used to explain the relative stabilities of He point defects in hcp-Ti. The relative stability of He defects in hcp-Ti is useful for He clustering and bubble nucleation in metal tritides, which provides the basis for development of improved atomistic models.

  17. Cathodic cage plasma deposition of TiN and TiO{sub 2} thin films on silicon substrates

    SciTech Connect (OSTI)

    Sousa, Romulo R. M. de; Sato, Patricia S.; Nascente, Pedro A. P.; Viana, Bartolomeu C.; Alves, Clodomiro; Nishimoto, Akio

    2015-07-15

    Cathodic cage plasma deposition (CCPD) was used for growing titanium nitride (TiN) and titanium dioxide (TiO{sub 2}) thin films on silicon substrates. The main advantages of the CCPD technique are the uniformity, tridimensionality, and high rate of the film deposition that occurs at higher pressures, lower temperatures, and lower treatment times than those used in conventional nitriding treatments. In this work, the influence of the temperature and gas atmosphere upon the characteristics of the deposited films was investigated. The TiN and TiO{sub 2} thin films were characterized by x-ray diffraction, scanning electron microscopy, and Raman spectroscopy to analyze their chemical, structural, and morphological characteristics, and the combination of these results indicates that the low-cost CCPD technique can be used to produce even and highly crystalline TiN and TiO{sub 2} films.

  18. Ferroelectric Self-assembled PbTiO3 Perovskite Nanostructures...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Perovskite Nanostructures onto (100)SrTiO3 Substrates from a Novel Microemulsion-aided Sol-Gel Preparation Figure 1. PbTiO3 nanostructures onto (100) SrTiO3 substrates....

  19. Optimizing optical absorption of TiO{sub 2} by alloying with...

    Office of Scientific and Technical Information (OSTI)

    Title: Optimizing optical absorption of TiOsub 2 by alloying with TiSsub 2 TiOsub 2 is an attractive material for photocatalytic water splitting, but its band gap is too ...

  20. Structure-Curie temperature relationships in BaTiO 3 -based ferroelect...

    Office of Scientific and Technical Information (OSTI)

    ferroelectric perovskites: Anomalous behavior of ( Ba , Cd ) TiO 3 from DFT, ... ferroelectric perovskites: Anomalous behavior of ( Ba , Cd ) TiO 3 from DFT, ...

  1. Effects of hydrochloric acid treatment of TiO{sub 2}nanoparticles...

    Office of Scientific and Technical Information (OSTI)

    Effects of hydrochloric acid treatment of TiOsub 2 nanoparticlesnanofibers bilayer film ... Title: Effects of hydrochloric acid treatment of TiOsub 2 nanoparticlesnanofibers ...

  2. Equation of State Model Quality Study for Ti and Ti64.

    SciTech Connect (OSTI)

    Wills, Ann Elisabet; Sanchez, Jason James

    2015-02-01

    Titanium and the titanium alloy Ti64 (6% aluminum, 4% vanadium and the balance ti- tanium) are materials used in many technologically important applications. To be able to computationally investigate and design these applications, accurate Equations of State (EOS) are needed and in many cases also additional constitutive relations. This report describes what data is available for constructing EOS for these two materials, and also describes some references giving data for stress-strain constitutive models. We also give some suggestions for projects to achieve improved EOS and constitutive models. In an appendix, we present a study of the 'cloud formation' issue observed in the ALEGRA code. This issue was one of the motivating factors for this literature search of available data for constructing improved EOS for Ti and Ti64. However, the study shows that the cloud formation issue is only marginally connected to the quality of the EOS, and, in fact, is a physical behavior of the system in question. We give some suggestions for settings in, and improvements of, the ALEGRA code to address this computational di culty.

  3. A=10B (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 10B) GENERAL: References to articles on general properties of 10B published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 10B located on our website at: (www.tunl.duke.edu/nucldata/General_Tables/10b.shtml). See also Table Prev. Table 10.18 preview 10.18 [Table of Energy Levels] (in PDF or PS). μ = +1.80064475 ± 0.00000057 μN: see (1989RA17); Q = +84.72

  4. A=19B (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (Not illustrated) 19B has been observed in the bombardment of Be by 12 MeV/A 56Fe ions (1984MU27) and in the fragmentation of 44 MeV/A 40Ar (1988GU1A) and 55 MeV/A 48Ca (1991MU19). See also (1989DE52). The mass excess adopted by (1993AU05) is 59.360 ± 0.400 MeV. Shell model predictions for low-lying levels are discussed in (1992WA22). See also (1989PO1K, 1990LO11

  5. A=20C (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    98TI06) (Not illustrated) 20C has been observed in heavy ion projectile fragmentation reactions (1987GI05, 1990MU06, 1991MU19) and in proton-induced target-fragmentation reactions (1987VI13, 1988MU08, 1993WOZZ). The atomic mass excess is 37.560 ± 0.200 MeV (1995AU04). It is then stable with respect to 19C + n and 18C + 2n by 3.3 and 3.5 MeV, respectively. β-delayed neutron emission has been observed (1987GI05, 1990MU06, 1991MU19). The half life and neutron emission probability have been

  6. A=20N (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    98TI06) (Not illustrated) 20N is particle stable. Its atomic mass excess is 21.770 ± 0.050 MeV (1995AU04). It has been observed in heavy-ion transfer (1989OR03) and projectile fragmentation reactions (1987GI05, 1988DUZT, 1988MU08, 1990MU06, 1991OR01) and in target fragmentation reactions (1988WO09, 1991RE02, 1993WOZZ). See also the review (1988VI1D). Mass measurements were reported in (1987GI05, 1988WO09, 1989OR03, 1991OR01, 1993WOZZ). Nuclear matter rms radii have been derived from

  7. A=3He (1987TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1987TI07) GENERAL: Ground State: Jπ = 1/2+, μ = -2.127624 ± 0.0000011 nm, M - A = 14.93132 ± 0.00003 MeV. General properties of the ground state of the A = 3 system are under 3H above. The wave function is predominantly S-state (~ 90%) with S'-state (1 - 2%) and D-state (~ 9%) admixtures (1975FI08, 1980PA12, 1984CI05, 1984CI09). For 3He the measured magnetic moment is μ = -2.127624 ± 0.0000011 nm (1978LEZA, 1978NE12). Calculations which include both impulse and pion exchange contributions

  8. A=3Li (1987TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1987TI07) GENERAL: The previous compilation (1975FI08) listed a small number of references reporting on the four reactions discussed below. Only one of the experiments cited contained any evidence for a 3p resonance, and the discussion suggested that the observed enhancement in 3He(p, n) was more likely a final state interaction. In the work reported since (1975FI08) and listed below, only (1974POZN) contains any mention of the tri-proton, and no evidence for its existence was observed. 1. 2H(p,

  9. A=4HE (1992TI02)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    He (1992TI02) (See Energy Level Diagrams for 4He) GENERAL: Ground state:Due to non-central forces, the wave function for the Jπ = 0+ ground state of 4He can be a positive-parity mixture of three 1S0, six 3P0, and five 5D0 orthogonal states (1967BE74). Of course, the symmetric S-wave component is the dominant part of the wavefunction, with significant D-wave and almost negligible P-wave contributions. Since the D-state admixture can be inferred from measurements such as the tensor analyzing

  10. A=4Li (1992TI02)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Li (1992TI02) (See Energy Level Diagrams for 4Li) GENERAL: The stability of 8B against particle decay (1988AJ01), in particular against decay into 4He + 4Li, sets an upper limit of 1.7 MeV on the separation energy of 4Li into p + 3He (1952SH44). The instability of 4H against particle decay (see 4H, GENERAL section) makes the particle stability of 4Li very unlikely, since the Coulomb energy of 4Li is approximately 1.7 MeV larger than that of 4H (1963WE10), and the nuclear energies should be

  11. A=5H (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (Not illustrated) See also the A = 5 introductory discussion titled A = 5 resonance parameters. The previous review (1988AJ01) noted that the 9Be(11B, 15O) reaction at E(11B) = 52 - 76 MeV showed no evidence for the formation of 5H (1986BE35, 1987BO40). For the earlier work see (1984AJ01). See also (1987KO47, 1988SEZJ). In several experiments on π- absorption at rest there is some evidence for the formation of a very broad (8 ± 3 MeV) resonance in the 5H system with Er = 7.4 ± 0.7

  12. A=5He (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (See Energy Level Diagrams for 5He) GENERAL: References to articles on general properties of 5He published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 5He located on our website at (www.tunl.duke.edu/NuclData/General_Tables/5he.shtml). See also Table Prev. Table 5.1 preview 5.1 [Table of Energy Levels] (in PDF or PS). See also the A = 5 introductory discussion titled A = 5 resonance

  13. A=5Li (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (See Energy Level Diagrams for 5Li) GENERAL: References to articles on general properties of 5Li published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 5Li located on our website at (www.tunl.duke.edu/NuclData/General_Tables/5li.shtml). See also Table Prev. Table 5.3 preview 5.3 [Table of Energy Levels] (in PDF or PS). See also the A = 5 introductory discussion titled A = 5 resonance

  14. A=6Be (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (See Energy Level Diagrams for 6Be) GENERAL: References to articles on general properties of 6Be published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 6Be located on our website at (www.tunl.duke.edu/NuclData/General_Tables/6be.shtml). See also Table Prev. Table 6.14 preview 6.14 [Table of Energy Levels] (in PDF or PS). 1. (a) 3He(3He, γ)6Be Qm = 11.4884 (b) 3He(3He, p)5Li Qm = 11.17

  15. A=6He (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (See Energy Level Diagrams for 6He) GENERAL: References to articles on general properties of 6He published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 6He located on our website at (www.tunl.duke.edu/NuclData/General_Tables/6he.shtml). See also Table Prev. Table 6.1 preview 6.1 [Table of Energy Levels] (in PDF or PS). Ground State Properties: The interaction radius of 6He, obtained

  16. A=6Li (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (See Energy Level Diagrams for 6Li) GENERAL: References to articles on general properties of 6He published since the previous review (1988AJ01) are grouped into categories and isted, along with brief descriptions of each item, in the General Tables for 6Li located on our website at (www.tunl.duke.edu/NuclData/General_Tables/6li.shtml). See also Table Prev. Table 6.4 preview 6.4 [Table of Energy Levels] (in PDF or PS). Ground State Properties: μ = +0.8220473(6) nm, +0.8220567(3) nm:

  17. A=6n (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (Not illustrated) 6n has not been observed. See (1979AJ01, 1988AJ01) and references cited there. More recently (1990AL40) reports a search for 6n in a 14C(7Li, 6n) activation experiment at E(7Li) = 82 MeV. No evidence for 6n was obtained. The method of angular potential functions was used by (1989GO18) in a calculation of the properties of multi-neutron systems which indicated that these systems have no bound states. The ground state energy of a six-neutron drop has been computed with

  18. A=7Be (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (See Energy Level Diagrams for 7Be) GENERAL: References to articles on general properties of 7Be published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 7Be located on our website at (www.tunl.duke.edu/NuclData/General_Tables/7be.shtml). See also Table Prev. Table 7.7 preview 7.7 [Table of Energy Levels] (in PDF or PS). The interaction nuclear radius of 7Be is 2.22 ± 0.02 fm

  19. A=7He (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (See Energy Level Diagrams for 7He) GENERAL: References to articles on general properties of 7He published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 7He located on our website at (www.tunl.duke.edu/NuclData/General_Tables/7he.shtml). See also Table Prev. Table 7.1 preview 7.1 [Table of Energy Levels] (in PDF or PS). Mass of 7He: The atomic mass excess of 7He is 26.11 ± 0.03 MeV:

  20. A=8B (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 8B) GENERAL: References to articles on general properties of 8B published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 8B located on our website at (www.tunl.duke.edu/nucldata/General_Tables/8b.shtml). See also Table Prev. Table 8.15 preview 8.15 [Table of Energy Levels] (in PDF or PS). μ = 1.0355 ± 0.0003 μN: see (1996FIZY). Q = 68.3 ± 2.1 mb

  1. A=8He (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 8He) GENERAL: References to articles on general properties of 8He published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 8He located on our website at (www.tunl.duke.edu/nucldata/General_Tables/8he.shtml). See also Table Prev. Table 8.1 preview 8.1 [Table of Energy Levels] (in PDF or PS). Mass of 8He: The atomic mass excess of 8He adopted by us and by

  2. A=9B (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 9B) GENERAL: References to articles on general properties of 9B published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 9B located on our website at (www.tunl.duke.edu/nucldata/General_Tables/9b.shtml). See also Table Prev. Table 9.13 preview 9.13 [Table of Energy Levels] (in PDF or PS). The low-lying levels of 9B have mainly [441] spatial symmetry and

  3. A=9Be (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 9Be) GENERAL: References to articles on general properties of 9Be published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 9Be located on our website at (www.tunl.duke.edu/nucldata/General_Tables/9be.shtml). See also Table Prev. Table 9.2 preview 9.2 [Table of Energy Levels] (in PDF or PS). μ = -1.1778 ± 0.0009 μN: see (1978LEZA); Q = 52.88 ± 0.38 mb:

  4. A=9C (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 9C) GENERAL: References to articles on general properties of 9C published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 9C located on our website at (www.tunl.duke.edu/nucldata/General_Tables/9c.shtml). See also Table Prev. Table 9.16 preview 9.16 [Table of Energy Levels] (in PDF or PS). Ground state properties: μ = -1.3914 ± 0.0005 μN (1996MA38). See

  5. A=9He (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See the Isobar Diagram for 9He) GENERAL: References to articles on general properties of 9He published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 9He located on our website at (www.tunl.duke.edu/nucldata/General_Tables/9he.shtml). Mass of 9He: Although the value adopted in the 2003 Atomic Mass Evaluation (2003AU02) for the 9He ground state is 40.939 ± 0.029 MeV based on the results

  6. A=9Li (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 9Li) GENERAL: References to articles on general properties of 9Li published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 9Li located on our website at (www.tunl.duke.edu/nucldata/General_Tables/9li.shtml). See also Table Prev. Table 9.1 preview 9.1 [Table of Energy Levels] (in PDF or PS). Ground state properties: μ = 3.4391 ± 0.0006 μN (1983CO11). See

  7. A=9N (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (Not illustrated) Not observed: see (1988AJ01). Mass excesses of 46.56 and 46.40 MeV have been estimated from two different mass formulae (2000PO32). 9N would then be proton unbound by ~ 4 MeV. However, mass formulae neither take into account the fact that the last occupied orbit(s) may change near the drip lines nor the fact that an extended low-l orbit leads to a lowered Coulomb energy. The suggested s-wave ground-state of 9He and a Coulomb energy estimated from the 11N ground state

  8. Expectations for the hard x-ray continuum and gamma-ray line fluxes from the typE IA supernova SN 2014J in M82

    SciTech Connect (OSTI)

    The, Lih-Sin [Department of Physics and Astronomy, Clemson University, SC 29634 (United States); Burrows, Adam, E-mail: tlihsin@clemson.edu, E-mail: burrows@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2014-05-10

    The hard X-ray continuum and gamma-ray lines from a Type Ia supernova dominate its integrated photon emissions and can provide unique diagnostics of the mass of the ejecta, the {sup 56}Ni yield and spatial distribution, its kinetic energy and expansion speed, and the mechanism of explosion. Such signatures and their time behavior 'X-ray' the bulk debris field in direct fashion, and do not depend on the ofttimes problematic and elaborate UV, optical, and near-infrared spectroscopy and radiative transfer that have informed the study of these events for decades. However, to date no hard photons have ever been detected from a Type Ia supernova in explosion. With the advent of the supernova SN 2014J in M82, at a distance of ?3.5 Mpc, this situation may soon change. Both NuSTAR and INTEGRAL have the potential to detect SN 2014J, and, if spectra and light curves can be measured, would usefully constrain the various explosion models published during the last ?30 yr. In support of these observational campaigns, we provide predictions for the hard X-ray continuum and gamma-line emissions for 15 Type Ia explosion models gleaned from the literature. The model set, containing as it does deflagration, delayed detonation, merger detonation, pulsational delayed detonation, and sub-Chandrasekhar helium detonation models, collectively spans a wide range of properties, and hence signatures. We provide a brief discussion of various diagnostics (with examples), but importantly make the spectral and line results available electronically to aid in the interpretation of the anticipated data.

  9. THE EFFECT OF THE PRE-DETONATION STELLAR INTERNAL VELOCITY PROFILE ON THE NUCLEOSYNTHETIC YIELDS IN TYPE Ia SUPERNOVA

    SciTech Connect (OSTI)

    Kim, Yeunjin; Jordan, G. C. IV; Graziani, Carlo; Lamb, D. Q.; Truran, J. W.; Meyer, B. S.

    2013-07-01

    A common model of the explosion mechanism of Type Ia supernovae is based on a delayed detonation of a white dwarf. A variety of models differ primarily in the method by which the deflagration leads to a detonation. A common feature of the models, however, is that all of them involve the propagation of the detonation through a white dwarf that is either expanding or contracting, where the stellar internal velocity profile depends on both time and space. In this work, we investigate the effects of the pre-detonation stellar internal velocity profile and the post-detonation velocity of expansion on the production of {alpha}-particle nuclei, including {sup 56}Ni, which are the primary nuclei produced by the detonation wave. We perform one-dimensional hydrodynamic simulations of the explosion phase of the white dwarf for center and off-center detonations with five different stellar velocity profiles at the onset of the detonation. In order to follow the complex flows and to calculate the nucleosynthetic yields, approximately 10,000 tracer particles were added to every simulation. We observe two distinct post-detonation expansion phases: rarefaction and bulk expansion. Almost all the burning to {sup 56}Ni occurs only in the rarefaction phase, and its expansion timescale is influenced by pre-existing flow structure in the star, in particular by the pre-detonation stellar velocity profile. We find that the mass fractions of the {alpha}-particle nuclei, including {sup 56}Ni, are tight functions of the empirical physical parameter {rho}{sub up}/v{sub down}, where {rho}{sub up} is the mass density immediately upstream of the detonation wave front and v{sub down} is the velocity of the flow immediately downstream of the detonation wave front. We also find that v{sub down} depends on the pre-detonation flow velocity. We conclude that the properties of the pre-existing flow, in particular the internal stellar velocity profile, influence the final isotopic composition of burned

  10. NT U.S. Department of Energy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... NSN 7540-D1-152-8070 STANDARD FORM 30 (REV. 10-83) Previous adition unusable Prescribed by GSA FAR (48 CFR) 53.243 ... TOTAL 67,635,770.56 4,851,382.42 TECC (ESTIMATED COST ...

  11. Microsoft Word - BoNT-Brunger.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Figure 1 Structure of the HcB-Syt-II complex. a, σ A -weighted F O - F C electron density map (contoured at 1.5 σ) around Syt-II, overlaid with the final refined model (Syt-II: red and green; HcB: grey). Please note that this map is model-bias free since it is calculated from the phases of the atomic model prior to the inclusion of the Syt-II peptide (using a lower resolution diffraction data set to 2.6 Å). b, Structure of the complex between HcB (salmon and gold) and Syt-II (red). Molecular

  12. Meteorological Towers Display for Windows NT

    Energy Science and Technology Software Center (OSTI)

    1999-05-20

    The Towers Display Program provides a convenient means of graphically depicting current wind speed and direction from a network of meteorological monitoring stations. The program was designed primarily for emergency response applications and, therefore, plots observed wind directions as a transport direction, i.e., the direction toward which the wind would transport a release of an atmospheric contaminant. Tabular summaries of wind speed and direction as well as temperature, relative humidity, and atmospheric turbulence measured atmore » each monitoring station can be displayed. The current implementation of the product at SRS displays data from eight Weather INformation and Display (WIND) System meteorological towers at SRS, meteorological stations established jointly by SRS/WSRC and the Augusta/Richmond County Emergency Management Agency in Augusta, GA, and National Weather Service stations in Augusta, GA. Wind speed and direction are plotted in a Beaufort scale format at the location of the station on a geographic map of the area. A GUI provides for easy specification of a desired date and time for the data to be displayed.« less

  13. Microsoft Word - NT0005682R21

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    10.8 374 1080 D3 0.1 5.9 0.3667 0.0209 6.3 8440 7.34 -212 11.1 312 900 D4 <0.03 3.9 0.2189 0.0186 6.2 8420 7.18 212 11.3 280 1020 nd- not determined Cd bdl (0.000025 mgL), Se...

  14. Gorchakova-IA

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Atl anta, Georgia, March 19-23, 2001 1 Estimate of Horizontal Cloud Inhomogeneity Effect on Solar Radiative Fluxes for Conditions of Winter Zvenigorod Experiment I. A. Gorchakova, G. S. Golitsyn, and I. I. Mokhov Oboukhov Institute of Atmospheric Physics Russian Academy of Sciences Moscow, Russia T. B. Zhuravleva Institute of Atmospheric Optics Tomsk, Russia Introduction Study of physical phenomena determining large-scale dynamical and energetic processes in the atmosphere requires quite full

  15. Type Ia Supernovae

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    that the universe is undergoing an accelerated expansion - a result which fits the General Relativity if a yet unknown form of "dark" energy is assumed to dominate the...

  16. IA Blog Archive

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2014 21:03:00 +0000 921386 at http:energy.gov Ministers Meet in Addis Ababa for U.S.-Africa Energy Ministerial http:energy.goviaarticlesministers-meet-addis-ababa-us-africa-...

  17. IA News Archive

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Dilma Rousseff of Brazil and he announced the creation of a Strategic Energy Dialogue (SED) to support the two countries' common goals of developing safe, secure and affordable...

  18. Fabrication of TiO{sub 2} Thick Film for Photocatalyst from Commercial TiO{sub 2} Powder

    SciTech Connect (OSTI)

    Asteti, S. Fuji; Syarif, D. Gustaman

    2008-03-17

    Photocatalytic activity of TiO{sub 2} thick film ceramics made of commercial TiO{sub 2} powder has been studied. The TiO{sub 2} powder was nano sized one that was derived from dried TiO{sub 2} suspension. The TiO{sub 2} suspension was made by pouring some blended commercial TiO{sub 2} powder into some amount of water. The paste of TiO{sub 2} was made by mixing the nano sized TiO{sub 2} powder with organic vehicle and glass frit. The paste was spread on a glass substrate. The paste was dried at 100 deg. C and heated at different temperatures (400 deg. C and 500 deg. C) for 60 minutes to produce thick film ceramics. The photocatalytic activity of these films was evaluated by measuring the concentration of a solution of methylene blue where the thick films were inside after being illuminated by UV light at various periods of times. The initial concentration of the methylene blue solution was 5 ppm. Structural analyses were carried out by X-ray diffraction (XRD). The XRD analyses showed that the produced thick film ceramic had mainly crystal structure of anatase. According to the photocatalytical data, it was known that the produced thick film ceramics were photocatalyst which were capable of decomposing an organic compound such as the methylene blue.

  19. Electrostatic carrier doping of GdTiO{sub 3}/SrTiO{sub 3} interfaces

    SciTech Connect (OSTI)

    Moetakef, Pouya; Cain, Tyler A.; Zhang, Jack Y.; Janotti, Anderson; Van de Walle, Chris G.; Stemmer, Susanne; Ouellette, Daniel G.; Allen, S. James; Klenov, Dmitri O.; Rajan, Siddharth

    2011-12-05

    Heterostructures and superlattices consisting of a prototype Mott insulator, GdTiO{sub 3}, and the band insulator SrTiO{sub 3} are grown by molecular beam epitaxy and show intrinsic electronic reconstruction, approximately 1/2 electron per surface unit cell at each GdTiO{sub 3}/SrTiO{sub 3} interface. The sheet carrier densities in all structures containing more than one unit cell of SrTiO{sub 3} are independent of layer thicknesses and growth sequences, indicating that the mobile carriers are in a high concentration, two-dimensional electron gas bound to the interface. These carrier densities closely meet the electrostatic requirements for compensating the fixed charge at these polar interfaces. Based on the experimental results, insights into interfacial band alignments, charge distribution, and the influence of different electrostatic boundary conditions are obtained.

  20. Phase equilibria, formation, crystal and electronic structure of ternary compounds in Ti-Ni-Sn and Ti-Ni-Sb ternary systems

    SciTech Connect (OSTI)

    Romaka, V.V.; Rogl, P.; Romaka, L.; Stadnyk, Yu.; Melnychenko, N.; Grytsiv, A.; Falmbigl, M.; Skryabina, N.

    2013-01-15

    The phase equilibria of the Ti-Ni-Sn and Ti-Ni-Sb ternary systems have been studied in the whole concentration range by means of X-ray and EPM analyses at 1073 K and 873 K, respectively. Four ternary intermetallic compounds TiNiSn (MgAgAs-type), TiNi{sub 2-x}Sn (MnCu{sub 2}Al-type), Ti{sub 2}Ni{sub 2}Sn (U{sub 2}Pt{sub 2}Sn-type), and Ti{sub 5}NiSn{sub 3} (Hf{sub 5}CuSn{sub 3}-type) are formed in Ti-Ni-Sn system at 1073 K. The TiNi{sub 2}Sn stannide is characterized by homogeneity in the range of 50-47 at% of Ni. The Ti-Ni-Sb ternary system at 873 K is characterized by formation of three ternary intermetallic compounds, Ti{sub 0.8}NiSb (MgAgAs-type), Ti{sub 5}Ni{sub 0.45}Sb{sub 2.55} (W{sub 5}Si{sub 3}-type), and Ti{sub 5}NiSb{sub 3} (Hf{sub 5}CuSn{sub 3}-type). The solubility of Ni in Ti{sub 0.8}NiSb decreases number of vacancies in Ti site up to Ti{sub 0.91}Ni{sub 1.1}Sb composition. - Graphical abstract: Isothermal section of the Ti-Ni-Sn phase diagram and DOS distribution in hypothetical TiNi{sub 1+x}Sn solid solution. Highlights: Black-Right-Pointing-Pointer Ti-Ni-Sn phase diagram was constructed at 1073 K. Black-Right-Pointing-Pointer Four ternary compounds are formed: TiNiSn, TiNi{sub 2-x}Sn, Ti{sub 2}Ni{sub 2}Sn, and Ti{sub 5}NiSn{sub 3}. Black-Right-Pointing-Pointer Three ternary compounds exist in Ti-Ni-Sb system at 873 K. Black-Right-Pointing-Pointer The TiNi{sub 2}Sb compound is absent.

  1. Development of Ti/Ti{sub 3}Sn functionally gradient material produced by eutectic bonding method

    SciTech Connect (OSTI)

    Kirihara, S.; Takeda, M.; Tsujimoto, T. [Ibaraki Univ., Hitachi (Japan). Faculty of Engineering] [Ibaraki Univ., Hitachi (Japan). Faculty of Engineering

    1996-07-15

    Although many materials which have a single function have been developed, future needs are anticipated to include materials which have various functions. A functionally gradient material (FGM) which has characteristics of two different materials is a promising candidate for multi-functional material. The present methods for production of FGM, however, are very complicated and costly. In this study the authors answer the serious problem of high production cost by fabricating the FGM by a eutectic bonding method. This fabrication method includes structural control of FGM by changing the cooling process. They describe Ti/Ti{sub 3}Sn FGM obtained by the eutectic bonding method, and tell how the structure of its composition gradient part is changed by controlling the cooling process.

  2. Application of Ti-alloys as compressor discs and blades

    SciTech Connect (OSTI)

    Helm, D.

    1999-07-01

    Ti-alloys are widely used as materials for compressor discs, blades, vanes and housings in modern aero-engines due to their excellent strength-to-weight ratio. Their high corrosion resistance and good weldability are additional factors for their application as main compressor components. A variety of different Ti-alloys have been developed in recent years and introduced into jet engines in order to fulfill the large spectrum of required mechanical properties. The main topic of the present paper is to describe the correlation between essential microstructural features of a number of Ti-alloys for compressor disc and blade applications and such mechanical properties as strength, creep and fatigue resistance, fracture toughness, and crack propagation behavior. It will be shown that for different engine requirements the choice of the suitable alloy, as well as tailoring of microstructural features with the aim to achieve an optimized balance of relevant mechanical properties, is necessary. The influence of thermomechanical treatment on morphology and dimensions of phases, and the resulting correlation to mechanical properties, will be discussed in detail for selected Ti-alloys, i.e., Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo and IMI 834 (Ti-5.8Al-4Sn-3.5Zr-0.5Mo-0.7Nb-0.35Si-0.06C). Additionally, effects of surface conditions caused by surface treatment (shot peening) or by service exposure (surface oxidation) will be presented.

  3. Nondestructive evaluation of Ni-Ti shape memory alloy

    SciTech Connect (OSTI)

    Meir, S.; Gordon, S.; Karsh, M.; Ayers, R.; Olson, D. L.; Wiezman, A.

    2011-06-23

    The nondestructive evaluation of nickel titanium (Ni-Ti) alloys for applications such as heat treatment for biomaterials applications (dental) and welding was investigated. Ni-Ti alloys and its ternary alloys are valued for mechanical properties in addition to the shape memory effect. Two analytical approaches were perused in this work. Assessment of the microstructure of the alloy that determines the martensitic start temperature (Ms) of Ni-Ti alloy as a function of heat treatment, and secondly, an attempt to evaluate a Friction Stir Welding, which involves thermo-mechanical processing of the alloy.

  4. A=16B (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (Not illustrated) This nucleus has not been observed in the 4.8 GeV proton bombardment of a uranium target. It is particle unstable. Its mass excess is predicted to be 37.97 MeV; it would then be unstable with respect to decay into 15B + n by 0.93 MeV. See (1985WA02, 1986AJ04). The ground state is predicted to have Jπ = 0- and the first three excited states are predicted to lie at 0.95, 1.10, and 1.55 MeV [Jπ = 2-, 3-, 4-] in a (0 + 1)ℏω space shell model calculation. See (1983ANZQ,

  5. A=16C (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (See Energy Level Diagrams for 16C) GENERAL: See Table Prev. Table 16.1 preview 16.1 [General Table] (in PDF or PS) and Table Prev. Table 16.2 preview 16.2 [Table of Energy Levels] (in PDF or PS) here. 1. 16C(β-)16N Qm = 8.012 The half life of 16C is 0.747 ± 0.008 sec. It decays to 16N*(0.12, 3.35, 4.32) [Jπ = 0-, 1+, 1+]: see Table Prev. Table 16.3 preview 16.3 (in PDF or PS) and (1993CH06). See also (1986AJ04) and see (1986KI05, 1988WA1E, 1992WA1L) for theoretical discussions of

  6. A=16Ne (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (See the Isobar Diagram for 16Ne) GENERAL: See Table Prev. Table 16.29 preview 16.29 [General Table] (in PDF or PS) and Table Prev. Table 16.32 preview 16.32 [Table of Energy Levels] (in PDF or PS). Mass of 16Ne: The Q-values of the 20Ne(α, 8He) and 16O(π+, π-) reactions lead to atomic mass excesses of 23.93 ± 0.08 MeV (1978KE06), 23.978 ± 0.024 MeV (1983WO01) and 24.048 ± 0.045 MeV (1980BU15) [recalculated using the (1985WA02) masses for 8He, 16O and 20Ne]. The weighted mean is

  7. A=17C (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (See the Isobar Diagram for 17C) The atomic mass excess given by (1988WA18) for 17C is 21035 ± 17 keV. See also (1986AN07). 17C is then stable with respect to 16C + n by 0.73 MeV. Eβ- (max) to 17Ng.s. = 13.16 MeV. See also (1986BI1A). The half-life of 17C has been measured to be 202 ± 17 msec (1986CU01), 220 ± 80 msec (1986DU07), 180 ± 31 msec (1988SA04), and 174 ± 31 msec (1991RE02). Relative intensities of β-delayed gammas were measured by (1986DU07, 1986HU1A, 1986JEZY) [see

  8. A=17Ne (1993TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    93TI07) (See the Isobar Diagram for 17Ne) GENERAL: See Table Prev. Table 17.26 preview 17.26 [Table of Energy Levels] (in PDF or PS). 1. (a) 17Ne(β+)17F* → 16O + p Qm = 13.928 (b) 17Ne(β+)17F → 13N + α Qm = 8.711 (c) 17Ne(β+)17F Qm = 14.529 The half-life of 17Ne has been reported as 109.0 ± 1.0 msec (1971HA05) and 109.3 ± 0.6 msec (1988BO39): the weighted mean is 109.2 ± 0.6 and we adopt it. The decay is primarily to the proton unstable states of 17F at 4.65, 5.49, 6.04 and 8.08 MeV

  9. A=18B (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (Not illustrated) 18B has not been observed in the bombardment of Ta by 44 MeV/A Ar ions (1985DE60, 1985LA03, 1986PO13) or in the bombardment of Be by 12 MeV/A 56Fe ions (1984MU27). 18B has been predicted to have a mass excess of 52.3 MeV (1993AU05). It would then be unstable with respect to 17B + n by 0.5 MeV: see (1978AJ03, 1985WA02). 18B is calculated to have Jπ = 4- and to have excited states at 0.62, 0.86 and 1.59 MeV with Jπ = 1-, 2- and 2- (1985PO10).The shell model calculations

  10. A=18F (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (See Energy Level Diagrams for 18F) GENERAL: See Table Prev. Table 18.23 preview 18.23 [General Table] (in PDF or PS) and Table Prev. Table 18.24 preview 18.24 [Table of Energy Levels] (in PDF or PS). μ1.12 = +2.86 ± 0.03 nm [see (1983AJ01)] Q1.12 = 0.13 ± 0.03 b [see (1983AJ01)]. 1. 18F(β+)18O Qm = 1.655 The positron decay is entirely to the ground state of 18O [Jπ = 0+, T = 1]; the half-life is 109.77 ± 0.05 min [see Table Prev. Table 18.11 preview 18.11 (in PDF or PS) in

  11. A=18N (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (See Energy Level Diagrams for 18N) GENERAL: See Table Prev. Table 18.3 preview 18.3 [General Table ] (in PDF or PS) and Table Prev. Table 18.4 preview 18.4 [Table of Energy Levels] (in PDF or PS). Mass of 18N: The atomic mass excess derived from the Q-value of the 18O(7Li, 7Be)18N reaction and adopted by (1993AU05) is 13.117 ± 0.020 MeV (1983PU01). 18N is then stable with respect to breakup into 17N + n by 2.825 MeV. See (1983AJ01) for the earlier work. 1. 18N(β-)18O Qm = -13.899 The

  12. A=18Ne (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (See Energy Level Diagrams for 18Ne) GENERAL: See Table Prev. Table 18.35 preview 18.35 [General Table] (in PDF or PS) and Table Prev. Table 18.36 preview 18.36 [Table of Energy Levels] (in PDF or PS). For B(E2) of 18Ne*(1.89) and other parameters see (1987RA01) and Table Prev. Table 2 preview 2 in the Introduction. 1. 18Ne(β+)18F Qm = 4.446 The half-life of 18Ne is 1672 ± 8 ms: see (1978AJ03) and (1983AD03). The decay is primarily to 18F*(0, 1.04, 1.70 MeV). In addition there is an

  13. A=19C (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (See the Isobar Diagram for 19C) 19C has been observed in the 0.8 GeV proton bombardment of thorium (1986VI09, 1988WO09) and in the fragmentation of 66 MeV/A argon ions (1987GI05) and in 44 MeV/A 22Ne on 181Ta, and in 112 MeV/A 20Ne on 12C (1994RAZW, 1995OZ02). The mass excess adopted by (1993AU05) is 32.23 ± 0.11 MeV. See also (1986VI09, 1987GI05, 1988WO09, 1991OR01). 19C is then stable with respect to decay into 18C + n by 0.16 MeV and into 17C + 2n by 4.35 MeV. The half-life was

  14. A=19N (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (See the Isobar Diagram for 19N) 19N has been produced in a number of different multinucleon transfer reactions (1983AJ01, 1987AJ02), and these results lead to an adopted value (1993AU05) of 15.860 ± 0.016 MeV for the mass excess. 19N is then stable with respect to decay into 18N + n by 5.33 MeV. The half-life has been measured to be 0.32 ± 0.10 s (1986DU07), 0.21+0.2-0.1 s (1988MU08), 0.235 ± 0.032 s (1988SA04), 0.300 ± 0.080 s (1988DUZT), 0.329 ± 0.019 s (1991RE02). The neutron

  15. A=19Na (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (See the Isobar Diagram for 19Na) This nucleus was observed in the 24Mg(p, 6He)19Na reaction at Ep = 54.7 MeV (1969CE01). A study via the 24Mg(3He, 8Li)19Na reaction at E(3He) = 76.3 MeV leads to an atomic mass excess of 12.929 ± 0.012 MeV for 19Na; it is then unstable with respect to breakup into 18Ne + p by 321 ± 13 keV. An excited state at Ex = 120 ± 10 keV is also reported (1975BE38, 1993AU05). See also (1987AJ02) and (1987PO01, 1987SA24, 1988CO15, 1990PO04, 1992AV03

  16. A=19Ne (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (See Energy Level Diagrams for 19Ne) GENERAL: See Table Prev. Table 19.26 preview 19.26 [General Table] (in PDF or PS) and Table Prev. Table 19.27 preview 19.27 [Table of Energy Levels] (in PDF or PS) here. μg.s. = -1.88542 (8) nm (1982MA39) μ0.239 = -0.740 (8) nm (1978LEZA) 1. 19Ne(β+)19F Qm = 3.238 We adopt the half-life of 19Ne suggested by (1983AD03): 17.34 ± 0.09 s. See also (1978AJ03). The decay is principally to 19Fg.s.: see Table Prev. Table 19.29 preview 19.29 (in PDF or

  17. A=19O (1995TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    95TI07) (See Energy Level Diagrams for 19O) GENERAL: See Table Prev. Table 19.1 preview 19.1 [General Table] (in PDF or PS) and Table Prev. Table 19.2 preview 19.2 [Table of Energy Levels] (in PDF or PS) here. 1. 19O(β-)19F Qm = 4.819 The weighted mean of several half-lives is 26.96 ± 0.07 s: see (1972AJ02, 1987AJ02). The decay is complex: see reaction 34 of 19F and Table Prev. Table 19.23 preview 19.23 (in PDF or PS) and Table Prev. Table 19.24 preview 19.24 (in PDF or PS). 2. 9Be(18O,

  18. A=20F (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    98TI06) (See Energy Level Diagrams for 20F) GENERAL: See Table Prev. Table 20.4 preview 20.4 [General Table] (in PDF or PS) and Table Prev. Table 20.5 preview 20.5 [Table of Energy Levels] (in PDF or PS) here. μ = +2.0935 (9) nm (1989RA17) Q = -0.042 (3) b (1989RA17) 1. 20F(β-)20Ne Qm = 7.025 The half-life of 20F is (11.163 ± 0.008) s (1992WA04), (11.11 ± 0.04) s (1995IT1C). For earlier measurements see (1987AJ02). 20F decays principally to 20Ne*(1.63): see 20Ne, reaction 37. 2. (a) 6Li(15N,

  19. A=20Mg (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    98TI06) (See the Isobar Diagram for 20Mg) 20Mg has been populated in the 24Mg(α, 8He) reaction at Eα = 127 and 156 MeV, in the 20Ne(3He, 3n) reaction at E(3He) = 70 MeV, and more recently in projectile fragmentation reactions. Reviews of proton rich nuclei and methods of production are presented in (1989AYZU, 1993SO13). See also (1990PO04). The super-allowed decay of 20Mg to the first T = 2 (Jπ = 0+) state of 20Na [Ex = 6.534 ± 0.013 MeV (1995PI03)] has been reported in early work (1979MO02,

  20. A=20Na (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    98TI06) (See Energy Level Diagrams for 20Na) GENERAL: See Table Prev. Table 20.32 preview 20.32 [General Table] (in PDF or PS) and Table Prev. Table 20.33 preview 20.33 [Table of Energy Levels] (in PDF or PS) here. μ = 0.3694 ± 0.0002 nm (1975SC20, 1989RA17) 1. 20Na(β+)20Ne Qm = 13.887 20Na decays by positron emission to 20Ne*(1.63) and to a number of other excited states of 20Ne: see Table Prev. Table 20.31 preview 20.31 (in PDF or PS) and reaction 59 in 20Ne. The half-life of 20Na is 447.9

  1. A=20O (1998TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    98TI06) (See Energy Level Diagrams for 20O) GENERAL: See Table Prev. Table 20.1 preview 20.1 [General Table] (in PDF or PS) and Table Prev. Table 20.2 preview 20.2 [Table of Energy Levels] (in PDF or PS) here. 1. 20O(β-)20F Qm = 3.814 20O decays with a half-life of 13.51 ± 0.05 s to the 1+ states 20F*(1.06, 3.49) with branching ratios (99.973 ± 0.003) and (0.027 ± 0.003)%, log f0t = 3.740 ± 0.006 and 3.65 ± 0.06, respectively (1987AL06). Upper limits for the branching to other states of

  2. A=3H (1987TI07)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1987TI07) (Not illustrated) GENERAL: Ground State: Jπ = 1/2+, μ = 2.978960 ± 0.000001 nm, M - A = 14.94991 ± 0.00003 MeV. The wave function for the triton bound state is calculated to be mostly S-state (~ 90%) with S'-state (~ 1%) and D-state (~ 9%) admixtures depending on the potentials used (1979SA15, 1986IS06). See also (1980HA10, 1980LO091983FR19, 1984CI05, 1984CI09, 1984MU23). The measured magnetic moment for 3H is μ = 2.978960 ± 0.000001 nm (1978LEZA). Calculations which include both

  3. A=4n (1992TI02)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    4n (1992TI02) GENERAL: The stability of 8He (1968BA48, 1968ME03, 1973FI04, 1988AJ01) sets an upper limit to the total binding energy of 4n, because the decay 8He → 4He + 4n does not occur (1964GO1B, 1964GO25). The most precisely determined mass excess of 8He (1988WA18) yields B(4n) ≤ 3.1 MeV. Noting that in all known nuclei the proton binding energy increases when two neutrons are added, (1964VL1A) show that B(4n) < -Q, where Q is the decay energy for 5H → 3H + 2n. Since Q > 0

  4. A=7B (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (See the Isobar Diagram for 7B) The mass excess of 7B adopted by (1997AU04) is 27.870 ± 0.070 MeV. It was obtained by averaging the values of 27.94 ± 0.10 MeV from the 10B(3He, 6He)7B reaction (1967MC14, 1988AJ01) and the value 27.800 ± 0.10 MeV obtained in the 7Li(π+, π-)7B reaction (1981SE1B). The width of the ground state is Γ = 1.4 ± 0.2 MeV: see (1967MC14, 1988AJ01). 7B is unbound with respect to 6Be + p, 5Li + 2p and 4He + 3p by 2.21, 1.61 and 3.38 MeV, respectively. The

  5. A=7H (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (Not illustrated) 7H has not been observed. Attempts have been made to detect it in the spontaneous fission of 252Cf (1982AL33) and in the 7Li(π-, π+) reaction [see (1984AJ01)]. A study of 9Be(π-, 2p) (1987GO25) found no evidence for 7H. See also the review of (1989OG1B) and the 7Li(π-, π+) investigation reported in (1989GR06). The ground state is calculated to have Jπ = 1/2+ and to be unstable with respect to 1n, 2n, 3n and 4n emission. Excited states are predicted at 4.84, 5.00

  6. A=8Be (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See Energy Level Diagrams for 8Be) GENERAL: References to articles on general properties of 8Be published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 8Be located on our website at (www.tunl.duke.edu/nucldata/General_Tables/8be.shtml). See also Table Prev. Table 8.9 preview 8.9 [Table of Energy Levels] (in PDF or PS). 1. 8Be → 4He4He Qm = 0.0918 Γcm for 8Beg.s. = 5.57 ± 0.25 eV:

  7. A=8C (2004TI06)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2004TI06) (See the Isobar Diagram for 8C) Mass of 8C: The atomic mass excess of 8C is 35094 ± 23 keV (2003AU03); Γcm = 230 ± 50 keV [Jπ = 0+; T = 2]: see (1979AJ01). 8C is stable with respect to 7B + p (Q = -0.07 MeV) and unstable with respect to 6Be + 2p (Q = 2.14), 5Li + 3p (Q = 1.55) and 4He + 4p (Q = 3.51). At E(3He) = 76 MeV the differential cross section for formation of 8Cg.s. in the 14N(3He, 9Li) reaction is ~ 5 nb/sr at θlab = 10°. The 12C(α, 8He)8C reaction has been studied at

  8. Modeling and experimental studies of oxide covered metal surfaces: TiO{sub 2}/Ti a model system. Progress report

    SciTech Connect (OSTI)

    Smyrl, W.H.

    1991-12-31

    Prior work in our laboratories at the Corrosion Research Center has shown that thin, anodic TiO{sub 2} films formed by the Slow Growth Mode (SGM) on polycrystalline titanium and microcrystalline with a texture that varies from one metal grain to another. Furthermore, the underlying metal grains are mapped by the photoelectrochemical response of the oxide. The same characteristics have also been demonstrated in our laboratory for ZnO grown on Zn. The TiO{sub 2}/Ti system has been chosen for study both because of its importance in energy systems, and because it can serve as a model system for other metal-metal oxide couples. The investigations of anodic TiO{sub 2} films on Ti have shown that the properties of thin films are consistent with the rutile form of the oxide. Both experimental data and theoretical calculations show the close resemblance to results on single crystal TiO{sub 2}. Furthermore, the modeling studies reveal that the optical transitions near the bandedge arise from the bulk band structure. The photoelectrochemical properties of anodic TiO{sub 2} films have now been shown to obey the simple Gaertner-Butler model for the semiconductor-electrolyte interface, with a few modifications. The most important deviation has now been shown to be a result of multiple internal reflections in the oxide film.

  9. Modeling and experimental studies of oxide covered metal surfaces: TiO sub 2 /Ti a model system

    SciTech Connect (OSTI)

    Smyrl, W.H.

    1991-01-01

    Prior work in our laboratories at the Corrosion Research Center has shown that thin, anodic TiO{sub 2} films formed by the Slow Growth Mode (SGM) on polycrystalline titanium and microcrystalline with a texture that varies from one metal grain to another. Furthermore, the underlying metal grains are mapped by the photoelectrochemical response of the oxide. The same characteristics have also been demonstrated in our laboratory for ZnO grown on Zn. The TiO{sub 2}/Ti system has been chosen for study both because of its importance in energy systems, and because it can serve as a model system for other metal-metal oxide couples. The investigations of anodic TiO{sub 2} films on Ti have shown that the properties of thin films are consistent with the rutile form of the oxide. Both experimental data and theoretical calculations show the close resemblance to results on single crystal TiO{sub 2}. Furthermore, the modeling studies reveal that the optical transitions near the bandedge arise from the bulk band structure. The photoelectrochemical properties of anodic TiO{sub 2} films have now been shown to obey the simple Gaertner-Butler model for the semiconductor-electrolyte interface, with a few modifications. The most important deviation has now been shown to be a result of multiple internal reflections in the oxide film.

  10. Photoinduced electron transfer in perylene-TiO2 nanoassemblies

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ABSTRACT: The photosensitization effect of three perylene dye derivatives on titanium dioxide nanoparticles (TiO2 NPs) has been investigated. The dyes used, 1,7-dibromoperylene-3,4...

  11. TI--CR--AL--O thin film resistors

    DOE Patents [OSTI]

    Jankowski, Alan F.; Schmid, Anthony P.

    2000-01-01

    Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  12. Martensite transformation of epitaxial Ni-Ti films

    SciTech Connect (OSTI)

    Buschbeck, J.; Kozhanov, A.; Kawasaki, J. K.; James, R. D.; Palmstroem, C. J.

    2011-05-09

    The structure and phase transformations of thin Ni-Ti shape memory alloy films grown by molecular beam epitaxy are investigated for compositions from 43 to 56 at. % Ti. Despite the substrate constraint, temperature dependent x-ray diffraction and resistivity measurements reveal reversible, martensitic phase transformations. The results suggest that these occur by an in-plane shear which does not disturb the lattice coherence at interfaces.

  13. A comparative study of precipitation effects in Ti only and Ti-V Ultra Low Carbon (ULC) strip steels

    SciTech Connect (OSTI)

    Ooi, S.W.; Fourlaris, G. . E-mail: g.fourlaris@swansea.ac.uk

    2006-04-15

    Two ULC steel grades were investigated, one based on combined vanadium and titanium additions and the other based on titanium only additions. It has been established that TiC formation during interphase precipitation retards grain growth of the {l_brace}111{r_brace} texture grains during continuous annealing and hence positively affects the r value of the Ti only steel. The formation of newly formed TiC precipitates on dislocations during continuous annealing has been found to result in an increase of the yield strength in both steel grades, as the annealing temperature is increased. It is also confirmed that VC particles formed during the coiling process dissolve during the continuous annealing cycles. Suitable continuous annealing cycles can be adopted to produce high formable steels with a bake hardening potential using the beneficial effects of combined Ti-V additions.

  14. Native SrTiO3 (001) surface layer from resonant Ti L2,3 reflectance spectroscopy

    SciTech Connect (OSTI)

    Valvidares, Manuel; Huijben, Mark; Yu, Pu; Ramesh, Ramamoorthy; Kortright, Jeffrey

    2010-11-03

    We quantitatively model resonant Ti L2,3 reflectivity Rs,p(q, hn) from several SrTiO3 (001) single crystals having different initial surface preparations and stored in ambient conditions before and between measurements. All samples exhibit unexpected 300 K Rs(hn) - Rp(hn) anisotropy corresponding to weak linear dichroism and tetragonal distortion of the TiO6 octahedra indicating a surface layer with properties different from cubic SrTiO3. Oscillations in Rs(q) confirm a ubiquitous surface layer 2-3 nm thick that evolves over a range of time scales. Resonant optical constant spectra derived from Rs,p(hn) assuming a uniform sample are refined using a single surface layer to fit measured Rs(q). Differences in surface layer and bulk optical properties indicate that the surface is significantly depleted in Sr and enriched in Ti and O. While consistent with the tendency of SrTiO3 surfaces toward non-stoichiometry, this layer does not conform simply to existing models for the near surface region and apparently forms via room temperature surface reactions with the ambient. This new quantitative spectral modeling approach is generally applicable and has potential to study near-surface properties of a variety of systems with unique chemical and electronic sensitivities.

  15. A=6H (2002TI10)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2002TI10) (See the Isobar Diagram for 6H) 6H was reported in the 7Li(7Li, 8B)6H reaction at E(7Li) = 82 MeV (1984AL08, 1985AL1G) [σ(θ) ~ 60 nb/sr at θ = 10°] and in the 9Be(11B, 14O)6H reaction at E(11B) = 88 MeV (1986BE35) [σ(θ) ~ 16 nb/sr at θ ~ 8°]. 6H is unstable with respect to breakup into 3H + 3n by 2.7 ± 0.4 MeV, Γ = 1.8 ± 0.5 MeV (1984AL08), 2.6 ± 0.5 MeV, Γ = 1.3 ± 0.5 MeV (1986BE35). The value adopted in the previous review (1988AJ01) is 2.7 ± 0.3 MeV, Γ = 1.6 ± 0.4

  16. Magneto-transport in LaTi{sub 1−x}Mn{sub x}O{sub 3}/SrTiO{sub 3} oxide heterostructures

    SciTech Connect (OSTI)

    Kumar, Pramod Dogra, Anjana Budhani, R. C.

    2014-04-24

    We report the growth of ultrathin film of Mn doped LaTiO{sub 3} on TiO{sub 2} terminated SrTiO{sub 3} (001) substrate by pulsed laser deposition (PLD) and their electrical transport characteristics including magnetoresistance (MR). Though the replacement of Mn in LaTiO{sub 3} at the Ti site in dilute limit does not affect the metallic behaviour of films but variation in resistance is observed. Normalised resistance behaviour is explained on the basis of variation in charge carriers and increased interaction between Mn atoms in the system under investigation.

  17. Morphology and structural development of reduced anatase-TiO{sub 2} by pure Ti powder upon annealing and nitridation: Synthesis of TiO{sub x} and TiO{sub x}N{sub y} powders

    SciTech Connect (OSTI)

    Bolokang, A.S.; Motaung, D.E.

    2015-02-15

    It is well known that nitriding of titanium is suitable for surface coating of biomaterials and in other applications such as anti-reflective coating, while oxygen-rich titanium oxynitride has been applied in thin film resistors and photocatalysis. Thus in this work anatase was reduced with pure titanium powder during annealing in argon. This was done to avoid any metallic contamination and unwanted residual metal doping. As a result, interesting and different types of particle morphology were synthesized when the pre-milled elemental anatase and titanium powders were mixed. The formation of metastable face centred cubic and monoclinic titanium monoxide was detected by the X-ray diffraction technique. The phases were confirmed by energy dispersive X-ray spectroscopy analysis. Raman analysis revealed weak intensity peaks for samples annealed in argon as compared to those annealed under nitrogen. - Graphical abstract: Display Omitted - Highlights: • Reaction of TiO{sub 2} and Ti induced metastable FCC and monoclinic TiO{sub x}. • Compositions of mixed powder were prepared from the unmilled and pre-milled powders. • Nitridation of TiO{sub x} yielded TiO{sub x}N{sub y} phase. • Mixed morphology was observed on all three powder samples.

  18. Incorporation of chromium into TiO{sub 2} nanopowders

    SciTech Connect (OSTI)

    Kollbek, Kamila; Sikora, Marcin; Kapusta, Czesław; Szlachetko, Jakub; Radecka, Marta; Lyson-Sypien, Barbara; Zakrzewska, Katarzyna

    2015-04-15

    Highlights: • Nanopowders of TiO{sub 2}:Cr with different amount of Cr dopant were obtained by flame spray synthesis, FSS. • Increase in the optical absorption and a shift of the absorption edge were observed upon Cr doping. • HERFD-XANES measurements indicated that the average valence state of titanium ions was preserved. • Increasing magnetic susceptibility of a paramagnetic character was observed upon Cr doping. - Abstract: The paper reports on the results of a study of optical, electronic and magnetic properties of TiO{sub 2} nanopowders doped with Cr ions. Diffused reflectance spectra reveal an increase in the optical absorption and a shift of the absorption edge towards lower energies upon Cr doping. Direct information on the Ti electronic state and the symmetry of its nearest environment is obtained from XANES Ti K-edge spectra. Magnetic behaviour is probed by means of the temperature dependence of DC magnetic susceptibility. Increasing magnetic susceptibility of a paramagnetic character is observed upon increasing chromium doping. The Curie constant of TiO{sub 2}:10 at.% Cr sample (0.12 emu K/mol Oe) is lower than that expected for Cr{sup 3+} (0.1875 emu K/mol Oe) possibly due to the appearance of Cr{sup 4+} or the presence of the orbital contribution to the magnetic moment.

  19. Interface-Induced Polarization in SrTiO3-LaCrO3 Superlattices...

    Office of Scientific and Technical Information (OSTI)

    Through x-ray absorption near edge spectroscopy and aberration-corrected scanning transmission electron microscopy we show that the Ti cations are displaced off-center in the TiO6 ...

  20. FIRST-PRINCIPLES PHASE STABILITY IN THE TI-V ALLOY SYSTEM (Journal...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: FIRST-PRINCIPLES PHASE STABILITY IN THE TI-V ALLOY SYSTEM Citation Details In-Document Search Title: FIRST-PRINCIPLES PHASE STABILITY IN THE TI-V ALLOY SYSTEM ...

  1. Local Metal and Deuterium Ordering in the Deuterated ZrTiNi C14...

    Office of Scientific and Technical Information (OSTI)

    Local Metal and Deuterium Ordering in the Deuterated ZrTiNi C14 Laves Phase Citation Details In-Document Search Title: Local Metal and Deuterium Ordering in the Deuterated ZrTiNi ...

  2. Deformation behavior of Nb nanowires in TiNiCu shape memory alloy...

    Office of Scientific and Technical Information (OSTI)

    in TiNiCu shape memory alloy matrix This content will become publicly available on August 18, 2016 Title: Deformation behavior of Nb nanowires in TiNiCu shape memory alloy matrix ...

  3. Electric control of magnetism at the Fe/BaTiO3 interface (Journal...

    Office of Scientific and Technical Information (OSTI)

    Electric control of magnetism at the FeBaTiO3 interface Citation Details In-Document Search Title: Electric control of magnetism at the FeBaTiO3 interface Interfacial ...

  4. High-Ti-concentration aerogels for bright x-ray sources (Technical...

    Office of Scientific and Technical Information (OSTI)

    Ti-concentration aerogels for bright x-ray sources Citation Details In-Document Search Title: High-Ti-concentration aerogels for bright x-ray sources Authors: Perez, F ; Patterson,...

  5. High-Ti-concentration aerogels for bright x-ray sources (Technical...

    Office of Scientific and Technical Information (OSTI)

    Ti-concentration aerogels for bright x-ray sources Citation Details In-Document Search Title: High-Ti-concentration aerogels for bright x-ray sources You are accessing a...

  6. Low temperature fabrication of perovskite solar cells with TiO...

    Office of Scientific and Technical Information (OSTI)

    the perovskite were fabricated from TiOsub 2 nanoparticles with different grain sizes. ... performance of solar cells was improved by combination of two TiOsub 2 nanoparticles. ...

  7. Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system...

    Office of Scientific and Technical Information (OSTI)

    Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Title: Ti3CrCu4: A possible ... Country of Publication: United States Language: English Word Cloud More Like This Free ...

  8. Conversion of 1,3-Propylene Glycol on Rutile TiO2(110) (Journal...

    Office of Scientific and Technical Information (OSTI)

    Conversion of 1,3-Propylene Glycol on Rutile TiO2(110) Citation Details In-Document Search Title: Conversion of 1,3-Propylene Glycol on Rutile TiO2(110) The adsorption of...

  9. Electrolyte Gate-Controlled Kondo Effect in SrTiO3 (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    Electrolyte Gate-Controlled Kondo Effect in SrTiO3 Prev Next Title: Electrolyte Gate-Controlled Kondo Effect in SrTiO3 Authors: Lee, Menyoung ; Williams, J. R. ; Zhang, Sipei ...

  10. Electric control of magnetism at the Fe/BaTiO3 interface (Journal...

    Office of Scientific and Technical Information (OSTI)

    Electric control of magnetism at the FeBaTiO3 interface Citation Details In-Document Search Title: Electric control of magnetism at the FeBaTiO3 interface You are accessing a ...

  11. Water adsorption induced in-plane domain switching on BaTiO{sub 3} surface

    SciTech Connect (OSTI)

    Li, X.; Bai, Y.; Su, Y. J.; Wang, B. C.

    2015-09-07

    In this study, the influences of the adsorption of water molecules on the changes in the atomic and electric structures of BaTiO{sub 3} surface were investigated using ab initio calculation. Water molecules are molecularly and dissociatively adsorbed on the BaTiO{sub 3} surface, which makes electrons transfer from water molecules to the BaTiO{sub 3} surface. The redistribution of electrons in the BaTiO{sub 3} surface layers weakens the Ba-O interactions and strengthens the Ti-O interactions, so that the Ti atom shifts in TiO{sub 2} plane, i.e., an in-plane domain switching. The adsorption of water molecules on BaTiO{sub 3} surfaces also results in a reduction in the surface rumpling.

  12. Visible Light Absorption of N-Doped TiO2 Rutile Using (LR/RT...

    Office of Scientific and Technical Information (OSTI)

    N-Doped TiO2 Rutile Using (LRRT)-TDDFT and Active Space EOMCCSD Calculations Citation Details In-Document Search Title: Visible Light Absorption of N-Doped TiO2 Rutile Using ...

  13. Coating power RF components with TiN

    SciTech Connect (OSTI)

    Kuchnir, M.; Hahn, E.

    1995-03-01

    A facility for coating RF power components with thin films of Ti and/or TiN has been in operation for some time at Fermilab supporting the Accelerator Division RF development work and the TESLA program. It has been experimentally verified that such coatings improve the performance of these components as far as withstanding higher electric fields. This is attributed to a reduction in the secondary electron emission coefficient of the surfaces when coated with a thin film containing titanium. The purpose of this Technical Memorandum is to describe the facility and the procedure used.

  14. Resonance photoelectron spectroscopy of TiX{sub 2} (X = S, Se, Te) titanium dichalcogenides

    SciTech Connect (OSTI)

    Shkvarin, A. S. Yarmoshenko, Yu. M.; Skorikov, N. A.; Yablonskikh, M. V.; Merentsov, A. I.; Shkvarina, E. G.; Titov, A. N.

    2012-11-15

    The photoelectron valence band spectra of TiS{sub 2}, TiSe{sub 2}, and TiTe{sub 2} dichalcogenides are investigated in the Ti 2p-3d resonance regime. Resonance bands in the vicinity of the Fermi energy are found for TiS{sub 2} and TiTe{sub 2}. The nature of these bands is analyzed based on model calculations of the density of electronic states in TiS{sub 2}, TiSe{sub 2}, and TiTe{sub 2} compounds intercalated by titanium atoms. Analysis of experimental data and their comparison with model calculations showed that these bands have different origins. It is found that the resonance enhancement of an additional band observed in TiS{sub 2} is explained by self-intercalation by titanium during the synthesis of this compound. The resonance enhancement in TiTe{sub 2} is caused by occupation of the 3d band in Ti.

  15. High strength, light weight Ti-Y composites and method of making same

    DOE Patents [OSTI]

    Verhoeven, John D.; Ellis, Timothy W.; Russell, Alan M.; Jones, Lawrence L.

    1993-04-06

    A high strength, light weight "in-situ" Ti-Y composite is produced by deformation processing a cast body having Ti and Y phase components distributed therein. The composite comprises elongated, ribbon-shaped Ti and Y phase components aligned along an axis of the deformed body.

  16. High strength, light weight Ti-Y composites and method of making same

    DOE Patents [OSTI]

    Verhoeven, J.D.; Ellis, T.W.; Russell, A.M.; Jones, L.L.

    1993-04-06

    A high strength, light weight in-situ'' Ti-Y composite is produced by deformation processing a cast body having Ti and Y phase components distributed therein. The composite comprises elongated, ribbon-shaped Ti and Y phase components aligned along an axis of the deformed body.

  17. Hysteretic electrical transport in BaTiO{sub 3}/Ba{sub 1?x}Sr{sub x}TiO{sub 3}/Ge heterostructures

    SciTech Connect (OSTI)

    Ngai, J. H.; Kumah, D. P.; Walker, F. J.; Ahn, C. H.

    2014-02-10

    We present electrical transport measurements of heterostructures comprised of BaTiO{sub 3} and Ba{sub 1?x}Sr{sub x}TiO{sub 3} epitaxially grown on Ge. Sr alloying imparts compressive strain to the BaTiO{sub 3}, which enables the thermal expansion mismatch between BaTiO{sub 3} and Ge to be overcome to achieve c-axis oriented growth. The conduction bands of BaTiO{sub 3} and Ba{sub 1?x}Sr{sub x}TiO{sub 3} are nearly aligned with the conduction band of Ge, which facilitates electron transport. Electrical transport measurements through the dielectric stack exhibit rectifying behavior and hysteresis, where the latter is consistent with ferroelectric switching.

  18. Induced Ti magnetization at La0.7Sr0.3MnO3 and BaTiO3 interfaces

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liu, Yaohua; Tornos, J.; te Velthuis, S. G. E.; Freeland, J. W.; Zhou, H.; Steadman, P.; Bencok, P.; Leon, C.; Santamaria, J.

    2016-04-01

    In artificial multiferroics hybrids consisting of ferromagnetic La0.7Sr0.3MnO3 (LSMO) and ferroelectric BaTiO3 epitaxial layers, net Ti moments are found from polarized resonant soft x-ray reflectivity and absorption. Moreover, the Ti dichroic reflectivity follows the Mn signal during the magnetization reversal, indicating exchange coupling between the Ti and Mn ions. But, the Ti dichroic reflectivity shows stronger temperature dependence than the Mn dichroic signal. Besides a reduced ferromagnetic exchange coupling in the interfacial LSMO layer, this may also be attributed to a weak Ti-Mn exchange coupling that is insufficient to overcome the thermal energy at elevated temperatures.

  19. Dye sensitized solar cell applications of CdTiO{sub 3}–TiO{sub 2} composite thin films deposited from single molecular complex

    SciTech Connect (OSTI)

    Ehsan, Muhammad Ali; Khaledi, Hamid; Pandikumar, Alagarsamy; Huang, Nay Ming; Arifin, Zainudin; Mazhar, Muhammad

    2015-10-15

    A heterobimetallic complex [Cd{sub 2}Ti{sub 4}(μ-O){sub 6}(TFA){sub 8}(THF){sub 6}]·1.5THF (1) (TFA=trifluoroacetato, THF=tetrahydrofuran) comprising of Cd:Ti (1:2) ratio was synthesized by a chemical reaction of cadmium (II) acetate with titanium (IV) isopropoxide and triflouroacetic acid in THF. The stoichiometry of (1) was recognized by single crystal X-ray diffraction, spectroscopic and elemental analyses. Thermal studies revealed that (1) neatly decomposes at 450 °C to furnish 1:1 ratio of cadmium titanate:titania composite oxides material. The thin films of CdTiO{sub 3}–TiO{sub 2} composite oxides were deposited at 550 °C on fluorine doped tin oxide coated conducting glass substrate in air ambient. The micro-structure, crystallinity, phase identification and chemical composition of microspherical architectured CdTiO{sub 3}–TiO{sub 2} composite thin film have been determined by scanning electron microscopy, X-ray diffraction, Raman spectroscopy and energy dispersive X-ray analysis. The scope of composite thin film having band gap of 3.1 eV was explored as photoanode for dye-sensitized solar cell application. - Graphical abstarct: Microspherical designed CdTiO{sub 3}–TiO{sub 2} composite oxides photoanode film has been fabricated from single source precursor [Cd{sub 2}Ti{sub 4}(μ-O){sub 6}(TFA){sub 8}(THF){sub 6}]·1.5THF via aerosol assisted chemical vapor deposition technique for dye sensitized solar cell application. - Highlights: • Synthesis and characterization of a heterobimetallic Cd–Ti complex. • Fabrication of CdTiO{sub 3}–TiO{sub 2} thin film photoelectrode. • Application as dye sensitized photoanode for solar application.

  20. OPTICAL AND NEAR-INFRARED POLARIMETRY OF HIGHLY REDDENED Type Ia SUPERNOVA 2014J: PECULIAR PROPERTIES OF DUST IN M82

    SciTech Connect (OSTI)

    Kawabata, K. S.; Akitaya, H.; Itoh, R.; Moritani, Y. [Hiroshima Astrophysical Science Center, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Yamanaka, M. [Department of Physics, Faculty of Science and Engineering, Konan University, Okamoto, Kobe, Hyogo 658-8501 (Japan); Maeda, K.; Nogami, D. [Department of Astronomy, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Ui, T.; Kawabata, M.; Mori, K.; Takaki, K.; Ueno, I.; Chiyonobu, S.; Harao, T.; Matsui, R.; Miyamoto, H.; Nagae, O. [Department of Physical Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526 (Japan); Nomoto, K.; Suzuki, N. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Tanaka, M., E-mail: kawabtkj@hiroshima-u.ac.jp [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); and others

    2014-11-01

    We present optical and near-infrared multi-band linear polarimetry of the highly reddened Type Ia supernova (SN) 2014J that appeared in M82. SN 2014J exhibits large polarization at shorter wavelengths, e.g., 4.8% in the B band, which decreases rapidly at longer wavelengths, while the position angle of the polarization remains at approximately 40 over the observed wavelength range. These polarimetric properties suggest that the observed polarization is likely predominantly caused by the interstellar dust within M82. Further analysis shows that the polarization peaks at a wavelengths much shorter than those obtained for the Galactic dust. The wavelength dependence of the polarization can be better described by an inverse power law rather than by the Serkowski law for Galactic interstellar polarization. These points suggest that the nature of the dust in M82 may be different from that in our Galaxy, with polarizing dust grains having a mean radius of <0.1 ?m.

  1. Epitaxial single-crystal thin films of MnxTi1-xO2-δ grown on...

    Office of Scientific and Technical Information (OSTI)

    Epitaxial single-crystal thin films of MnxTi1-xO2- grown on (rutile)TiO2 substrates with ... Title: Epitaxial single-crystal thin films of MnxTi1-xO2- grown on (rutile)TiO2 ...

  2. Adhesion evaluation of TiN and (Ti, Al)N coatings on titanium 6Al-4V

    SciTech Connect (OSTI)

    James, R.D.; Gruss, K.A.; Horie, Y.; Davis, R.F.; Paisley, D.L.; Parthasarthi, S.; Tittmann, B.R.

    1996-12-31

    The metallic components of gas turbine engines are continually subjected to hostile atmospheres. Nitride coatings improve the performance of the metallic compressor blades in these engines. To assess the adhesion of nitride coatings on metals, titanium 6% aluminum 4% vanadium substrates were coated with titanium nitride (TiN) using both cathodic arc and electron beam evaporation. Titanium aluminum nitride ((Ti, Al)N) was also deposited using cathodic arc evaporation. The interfaces of the coated samples were loaded in tension using a high speed shock wave which caused spallation either at the interface, in the coating or in the metal. Scanning acoustic microscopy analysis of the spalled samples detected delaminations at the interface in the samples deposited by cathodic arc evaporation. DYNA2D modeling of plate impact spallation experiments revealed the tensile adhesion strength for TiN deposited by both techniques was {approx} 2.0 GPa. The tensile adhesion strength for (Ti, Al)N was less than 1.5 GPa.

  3. Laser hydrothermal reductive ablation of titanium monoxide: Hydrated TiO particles with modified Ti/O surface

    SciTech Connect (OSTI)

    Blazevska-Gilev, Jadranka; Jandova, Vera; Kupcik, Jaroslav; Bastl, Zdenek; Subrt, Jan; Bezdicka, Petr; Pola, Josef

    2013-01-15

    IR laser- and UV laser-induced ablation of titanium monoxide (TM) in hydrogen (50 Torr) is compared to the same process induced in vacuum and shown to result in deposition of hydrated surface modified nanostructured titanium suboxide films. Complementary analyses of the films deposited in vacuum and in hydrogen by Fourier transform infrared, Raman and X-ray photoelectron spectroscopy, X-ray diffraction and electron microscopy allowed to determine different features of both films and propose a mechanism of surface modification of ejected particles, which involves hydrothermal reduction of TM and subsequent reactions of evolved water. The films exert good adhesion to metal and quartz surfaces and are hydrophobic in spite of having their surface coated with adsorbed water. - Graphical abstract: Laser ablation of titanium monoxide (TiO) in hydrogen involves a sequence of H{sub 2} and H{sub 2}O eliminations and additions and yields hydrated amorphous nanostructured titanium suboxide which is richer in oxygen than TiO. Highlights: Black-Right-Pointing-Pointer IR and UV laser ablated particles of titanium monoxide (TiO) undergo amorphization. Black-Right-Pointing-Pointer Films deposited in vacuum have TiO stoichiometry and are oxidized in atmosphere. Black-Right-Pointing-Pointer Films deposited in hydrogen are hydrated and have more O in topmost layers. Black-Right-Pointing-Pointer Films modification in hydrogen is explained by reactions in hydrogen plasma.

  4. Dual Phase Li4 Ti5O12TiO2 Nanowire Arrays As Integrated Anodes For High-rate Lithium-ion Batteries

    SciTech Connect (OSTI)

    Liao, Jin; Chabot, Victor; Gu, Meng; Wang, Chong M.; Xiao, Xingcheng; Chen, Zhongwei

    2014-08-19

    Lithium titanate (Li4Ti5O12) is well known as a zero strain material inherently, which provides excellent long cycle stability as a negative electrode for lithium ion batteries. However, the low specific capacity (175 mA h g?1) limits it to power batteries although the low electrical conductivity is another intrinsic issue need to be solved. In this work, we developed a facile hydrothermal and ion-exchange route to synthesize the self-supported dual-phase Li4Ti5O12TiO2 nanowire arrays to further improve its capacity as well as rate capability. The ratio of Li4Ti5O12 to TiO2 in the dual phase Li4Ti5O12TiO2 nanowire is around 2:1. The introduction of TiO2 into Li4Ti5O12 increases the specific capacity. More importantly, by interface design, it creates a dual-phase nanostructure with high grain boundary density that facilitates both electron and Li ion transport. Compared with phase-pure nanowire Li4Ti5O12 and TiO2 nanaowire arrays, the dual-phase nanowire electrode yielded superior rate capability (135.5 at 5 C, 129.4 at 10 C, 120.2 at 20 C and 115.5 mA h g?1 at 30 C). In-situ transmission electron microscope clearly shows the near zero deformation of the dual phase structure, which explains its excellent cycle stability.

  5. Structural and chemical characterization of BaTiO{sub 3} nanorods

    SciTech Connect (OSTI)

    Zagar, K.; Recnik, A.; Sturm, S.; Gajovic, A.; Ceh, M.

    2011-03-15

    Research highlights: {yields} Polycrystalline BaTiO{sub 3} nanorods were synthesized with EPD into AAO templates. {yields} Nanorods are composed of crystalline, nanosized grains with pseudo-cubic structure. {yields} Integrowth of hexagonal BaTiO{sub 3} polymorph within pseudo-cubic structure was observed. -- Abstract: An electron-microscopy investigation was performed on BaTiO{sub 3} nanorods that were processed by sol-gel electrophoretic deposition (EPD) into anodic aluminium oxide (AAO) membranes. The BaTiO{sub 3} nanorods grown within the template membranes had diameters ranging from 150 to 200 nm, with an average length of 10-50 {mu}m. By using various electron-microscopy techniques we showed that the processed BaTiO{sub 3} nanorods were homogeneous in their chemical composition. The BaTiO{sub 3} nanorods were always polycrystalline and were composed of well-crystallized, defect-free, pseudo-cubic BaTiO{sub 3} grains, ranging from 10 to 30 nm. No intergranular phases were observed between the BaTiO{sub 3} grains. A low-temperature hexagonal polymorph that is coherently intergrown with the BaTiO{sub 3} perovskite matrix was also observed as a minor phase. When annealing the AAO templates containing the BaTiO{sub 3} sol in an oxygen atmosphere the presence of the hexagonal polymorph was diminished.

  6. Synthesis of visible light-activated TiO{sub 2} photocatalyst via surface organic modification

    SciTech Connect (OSTI)

    Jiang Dong Xu Yao Hou Bo; Wu Dong; Sun Yuhan

    2007-05-15

    A visible light-activated TiO{sub 2} photocatalyst was successfully synthesized by the surface organic modification to sol-gel-hydrothermal synthesized TiO{sub 2}. The surface hydroxyls of TiO{sub 2} nanoparticles reacted with the active -NCO groups of tolylene diisocyanate (TDI) to form a surface complex that was confirmed by the FT-IR and XPS spectra. Due to the existence of surface complex, the absorption edge of as-prepared TDI-modified TiO{sub 2} nanomaterial extended well into visible region. Compared with unmodified TiO{sub 2} and Degussa P25, the TDI-modified TiO{sub 2} photocatalysts showed higher activity for the photocatalytic degradation of methylene blue under visible light irradiation. - Graphical abstract: A visible light-activated TiO{sub 2} photocatalyst was successfully synthesized by the surface organic modification to TiO{sub 2}. The surface hydroxyls of TiO{sub 2} nanoparticles reacted with the active -NCO groups of tolylene diisocyanate (TDI) to form a surface complex. The TDI-modified TiO{sub 2} photocatalysts showed higher activity for the photocatalytic degradation of methylene blue under visible light irradiation.

  7. The Effect of Ramp Rate on the C49 to C54 Titanium Disilicide Phase Transformation from Ti and Ti(Ta)

    SciTech Connect (OSTI)

    BAILEY, GLENN A.; HU, YAO ZHI; SMITH, PAUL M.; TAY, SING PIN

    1999-09-22

    The C49 to C54 TiSi{sub 2} transformation temperature is shown to be reduced by increasing the ramp rate during rapid thermal processing and this effect is more pronounced for thinner initial Ti and Ti(Ta) films. Experiments were performed on blanket wafers and on wafers that had patterned polycrystalline Si lines with Si{sub 3}N{sub 4} sidewall spacers. Changing the ramp rate caused no change in the transformation temperature for 60 nm blanket Ti films. For blanket Ti films of 25 or 40 nm, however, increasing the ramp rate from 7 to 180 C/s decreased the transformation temperature by 15 C. Studies of patterned lines indicate that sheet resistance of narrow lines is reduced by increased ramp rates for both Ti and Ti(Ta) films, especially as the linewidths decrease below 0.4 {micro}m. This improvement is particularly pronounced for the thinnest Ti(Ta) films, which exhibited almost no linewidth effect after being annealed with a ramp rate of 75 C/s.

  8. Ti{sub 5}O{sub 5} superstructures of cubic titanium monoxide

    SciTech Connect (OSTI)

    Gusev, A. I.

    2013-08-15

    A cubic model is proposed for the Ti{sub 5}O{sub 5} (Ti{sub 5} Black-Small-Square O{sub 5}{open_square} {identical_to} Ti{sub 90} Black-Small-Square {sub 18}O{sub 90}{open_square}{sub 18}) superstructure of nonstoichiometric titanium monoxide Ti{sub x}O{sub z} with double imperfection. The unit cell of the cubic Ti{sub 5}O{sub 5} superstructure has the threefold lattice parameter of the unit cell of the basis disordered B1 structure of Ti{sub x}O{sub z} monoxide and belongs to space group Pm 3-bar m . The channel of the disorder-order transition, i.e., Ti{sub x}O{sub z} (space group Fm 3-bar m)-Ti{sub 5}O{sub 5} (space group Pm 3-bar m), includes 75 superstructure vectors of seven stars (k{sub 10}), (k{sub 7}), (k{sub 6(1)}), (k{sub 6(2)}), (k{sub 4(1)}), (k{sub 4(2)}), and (k{sub 1}). The distribution functions of Ti and O atoms over the sites of the cubic Ti{sub 5}O{sub 5} superstructure are calculated. A comparison of the X-ray and electron diffraction data obtained for ordered TiO{sub 1.087} monoxide with the theoretical simulation results supports the existence of the cubic Ti{sub 5}O{sub 5} superstructure. The cubic (space group Pm 3-bar m) Ti{sub 5}O{sub 5} superstructure is shown to be a high-temperature structure relative to the well-known monoclinic (space group C2/m) superstructure of the same type.

  9. TYPE Ia SUPERNOVA REMNANT SHELL AT z = 3.5 SEEN IN THE THREE SIGHTLINES TOWARD THE GRAVITATIONALLY LENSED QSO B1422+231

    SciTech Connect (OSTI)

    Hamano, Satoshi; Kobayashi, Naoto [Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Kondo, Sohei [Koyama Astronomical Observatory, Kyoto-Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555 (Japan); Tsujimoto, Takuji [National Astronomical Observatory of Japan and Department of Astronomical Science, Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Okoshi, Katsuya [Faculty of Industrial Science and Technology, Tokyo University of Science, 102-1 Tomino, Oshamanbe, Hokkaido 049-3514 (Japan); Shigeyama, Toshikazu, E-mail: hamano@ioa.s.u-tokyo.ac.jp [Research Center for the Early Universe, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan)

    2012-08-01

    Using the Subaru 8.2 m Telescope with the IRCS Echelle spectrograph, we obtained high-resolution (R = 10,000) near-infrared (1.01-1.38 {mu}m) spectra of images A and B of the gravitationally lensed QSO B1422+231 (z = 3.628) consisting of four known lensed images. We detected Mg II absorption lines at z = 3.54, which show a large variance of column densities ({approx}0.3 dex) and velocities ({approx}10 km s{sup -1}) between sightlines A and B with a projected separation of only 8.4h{sup -1}{sub 70} pc at that redshift. This is the smallest spatial structure of the high-z gas clouds ever detected after Rauch et al. found a 20 pc scale structure for the same z = 3.54 absorption system using optical spectra of images A and C. The observed systematic variances imply that the system is an expanding shell as originally suggested by Rauch et al. By combining the data for three sightlines, we managed to constrain the radius and expansion velocity of the shell ({approx}50-100 pc, 130 km s{sup -1}), concluding that the shell is truly a supernova remnant (SNR) rather than other types of shell objects, such as a giant H II region. We also detected strong Fe II absorption lines for this system, but with much broader Doppler width than that of {alpha}-element lines. We suggest that this Fe II absorption line originates in a localized Fe II-rich gas cloud that is not completely mixed with plowed ambient interstellar gas clouds showing other {alpha}-element low-ion absorption lines. Along with the Fe richness, we conclude that the SNR is produced by an SN Ia explosion.

  10. Effect of neutron irradiation on defect evolution in Ti3SiC2 and Ti2AlC

    SciTech Connect (OSTI)

    Tallman, Darin J.; He, Lingfeng; Garcia-Diaz, Brenda L.; Hoffman, Elizabeth N.; Kohse, Gordon; Sindelar, Robert L.; Barsoum, Michel W.

    2015-10-23

    Here, we report on the characterization of defects formed in polycrystalline Ti3SiC2 and Ti2AlC samples exposed to neutron irradiation – up to 0.1 displacements per atom (dpa) at 350 ± 40 °C or 695 ± 25 °C, and up to 0.4 dpa at 350 ± 40 °C. Black spots are observed in both Ti3SiC2 and Ti2AlC after irradiation to both 0.1 and 0.4 dpa at 350 °C. After irradiation to 0.1 dpa at 695 °C, small basal dislocation loops, with a Burgers vector of b = 1/2 [0001] are observed in both materials. At 9 ± 3 and 10 ± 5 nm, the loop diameters in the Ti3SiC2 and Ti2AlC samples, respectively, were comparable. At 1 × 1023 loops/m3, the dislocation loop density in Ti2AlC was ≈1.5 orders of magnitude greater than in Ti3SiC2, at 3 x 1021 loops/m3. After irradiation at 350 °C, extensive microcracking was observed in Ti2AlC, but not in Ti3SiC2. The room temperature electrical resistivities increased as a function of neutron dose for all samples tested, and appear to saturate in the case of Ti3SiC2. The MAX phases are unequivocally more neutron radiation tolerant than the impurity phases TiC and Al2O3. Based on these results, Ti3SiC2 appears to be a more promising MAX phase candidate for high temperature nuclear applications than Ti2AlC.

  11. Characterization of irradiation damage distribution near TiO{sub 2}/SrTiO{sub 3} interfaces using coherent acoustic phonon interferometry

    SciTech Connect (OSTI)

    Yarotski, Dmitry; Yan Li; Jia Quanxi; Taylor, Antoinette J.; Fu Engang; Wang Yongqiang; Uberuaga, Blas P.

    2012-06-18

    We apply ultrafast coherent acoustic phonon interferometry to characterize the distribution of the radiation damage near the TiO{sub 2}/SrTiO{sub 3} interfaces. We show that the optical and mechanical properties of anatase TiO{sub 2} remain unaffected by the radiation dosages in the 0.1 Division-Sign 5 dpa (displacements per atom) range, while the degraded optical response indicates a significant defect accumulation in the interfacial region of SrTiO{sub 3} at 0.1 dpa and subsequent amorphization at 3 dpa. Comparison between the theoretical simulations and the experimental results reveals an almost threefold reduction of the sound velocity in the irradiated SrTiO{sub 3} layer with peak damage levels of 3 and 5 dpa.

  12. Reactions of hydrogen with V-Cr-Ti alloys

    SciTech Connect (OSTI)

    DiStefano, J.R.; DeVan, J.H.; Chitwood, L.D.; Roehrig, D.H.

    1998-09-01

    In the absence of increases in oxygen concentration, additions of up to 400 ppm hydrogen to V-4 Cr-4 Ti did not result in significant embrittlement as determined by room temperature tensile tests. However, when hydrogen approached 700 ppm after exposure at 325 C, rapid embrittlement occurred. In this latter case, hydride formation is the presumed embrittlement cause. When oxygen was added during or prior to hydrogen exposure, synergistic effects led to significant embrittlement by 100 ppm hydrogen.

  13. LaTiO₃/KTaO₃ interfaces: A new two-dimensional electron gas system

    SciTech Connect (OSTI)

    Zou, K.; Ismail-Beigi, Sohrab; Kisslinger, Kim; Shen, Xuan; Su, Dong; Walker, F. J.; Ahn, C. H.

    2015-03-01

    We report a new 2D electron gas (2DEG) system at the interface between a Mott insulator, LaTiO₃, and a band insulator, KTaO₃. For LaTiO₃/KTaO₃ interfaces, we observe metallic conduction from 2 K to 300 K. One serious technological limitation of SrTiO₃-based conducting oxide interfaces for electronics applications is the relatively low carrier mobility (0.5-10 cm²/V s) of SrTiO₃ at room temperature. By using KTaO₃, we achieve mobilities in LaTiO₃/KTaO₃ interfaces as high as 21 cm²/V s at room temperature, over a factor of 3 higher than observed in doped bulk SrTiO₃. By density functional theory, we attribute the higher mobility in KTaO₃ 2DEGs to the smaller effective mass for electrons in KTaO₃.

  14. LaTiO₃/KTaO₃ interfaces: A new two-dimensional electron gas system

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zou, K.; Ismail-Beigi, Sohrab; Kisslinger, Kim; Shen, Xuan; Su, Dong; Walker, F. J.; Ahn, C. H.

    2015-03-01

    We report a new 2D electron gas (2DEG) system at the interface between a Mott insulator, LaTiO₃, and a band insulator, KTaO₃. For LaTiO₃/KTaO₃ interfaces, we observe metallic conduction from 2 K to 300 K. One serious technological limitation of SrTiO₃-based conducting oxide interfaces for electronics applications is the relatively low carrier mobility (0.5-10 cm²/V s) of SrTiO₃ at room temperature. By using KTaO₃, we achieve mobilities in LaTiO₃/KTaO₃ interfaces as high as 21 cm²/V s at room temperature, over a factor of 3 higher than observed in doped bulk SrTiO₃. By density functional theory, we attribute the higher mobilitymore » in KTaO₃ 2DEGs to the smaller effective mass for electrons in KTaO₃.« less

  15. Laser cladding of Ti-6Al-4V with various carbide powders

    SciTech Connect (OSTI)

    Folkes, J.A.; Shibata, K. )

    1994-06-01

    Laser cladding Ti-6Al-4V can be achieved with various weight percentages of different carbide powders. The microstructure and morphology of the clad layer is determined by the cladding powder composition, for a given set of laser parameters, such that 10 and 20 wt% Cr[sub 3]C[sub 2] results in a [beta] + TiC clad microstructure; 10 and 20 wt% WC results in an [alpha] + TiC clad microstructure (plus some original WC); and Mo[sub 2]C gives an [alpha] + [beta] + TiC or [beta] + TiC structure, depending on the weight percentage of Mo[sub 2]C. The morphology of the TiC in all cases is dendritic or feathery, depending on the carbide content. The microstructure observed in all cases agreed well with that theoretically predicted from the energetics of carbide formation and [beta]-stabilizing properties of each element.

  16. Heterojunction band offsets and dipole formation at BaTiO{sub 3}/SrTiO{sub 3} interfaces

    SciTech Connect (OSTI)

    Balaz, Snjezana; Zeng, Zhaoquan; Brillson, Leonard J.; Department of Physics, The Ohio State University, 191 West Woodruff, Columbus, Ohio 43210

    2013-11-14

    We used a complement of photoemission and cathodoluminescence techniques to measure formation of the BaTiO{sub 3} (BTO) on SrTiO{sub 3} (STO) heterojunction band offset grown monolayer by monolayer by molecular beam epitaxy. X-ray photoemission spectroscopy (XPS) provided core level and valence band edge energies to monitor the valence band offset in-situ as the first few crystalline BTO monolayers formed on the STO substrate. Ultraviolet photoemission spectroscopy (UPS) measured Fermi level positions within the band gap, work functions, and ionization potentials of the growing BTO film. Depth-resolved cathodoluminescence spectroscopy measured energies and densities of interface states at the buried heterojunction. Kraut-based XPS heterojunction band offsets provided evidence for STO/BTO heterojunction linearity, i.e., commutativity and transitivity. In contrast, UPS and XPS revealed a large dipole associated either with local charge transfer or strain-induced polarization within the BTO epilayer.

  17. Anisotropic swelling and microcracking of neutron irradiated Ti3AlC2-Ti5Al2C3 materials

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ang, Caen K.; Silva, Chinthaka M.; Shih, Chunghao Phillip; Koyanagi, Takaaki; Katoh, Yutai; Zinkle, Steven J.

    2015-12-17

    Mn + 1AXn (MAX) phase materials based on Ti–Al–C have been irradiated at 400 °C (673 K) with fission neutrons to a fluence of 2 × 1025 n/m2 (E > 0.1 MeV), corresponding to ~ 2 displacements per atom (dpa). We report preliminary results of microcracking in the Al-containing MAX phase, which contained the phases Ti3AlC2 and Ti5Al2C3. Equibiaxial ring-on-ring tests of irradiated coupons showed that samples retained 10% of pre-irradiated strength. Volumetric swelling of up to 4% was observed. Phase analysis and microscopy suggest that anisotropic lattice parameter swelling caused microcracking. Lastly, variants of titanium aluminum carbide may bemore » unsuitable materials for irradiation at light water reactor-relevant temperatures.« less

  18. Effect Of The Plasma Deposition Parameters On The Properties Of Ti/TiN Multilayers For Hard Coatings Applications

    SciTech Connect (OSTI)

    Saoula, N.; Henda, K.; Kesri, R.

    2008-09-23

    In this study, we present the effect of the plasma deposition parameters on the mechanical properties of Ti/TiN multilayers. The elaboration of our films has been carried out by RF-Magnetron Sputtering (13.56 MHz) under nitrogen and argon reactive plasma at low pressure. The film depositions have been done on steel substrates. The first step of our study was the optimization of the depositions conditions in order to obtain good quality films. The amount of nitrogen in the sputtering gases being fixed at 10%. The total pressure was set between 2mTorr to 10mTorr. The deposited multilayers were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM) and micro-indentation.

  19. Spin and orbital Ti magnetism at LaMnO3/SrTiO3 interfaces

    SciTech Connect (OSTI)

    Garcial-Barriocanal, J; Cezar, J. C.; Bruno, F. Y.; Thakur, P.; Brookes, N. B.; Utfeld, C.; Riviera-Calzada, A.; Giblin, S. R.; Taylor, J. W.; Duffy, J. A.; Dugdale, S. B.; Nakamura, T.; Kodama, K.; Leon, C.; Okamoto, Satoshi; Santamaria, J.

    2010-01-01

    In systems with strong electron-lattice coupling, such as manganites, orbital degeneracy is lifted, what causes a null expectation value of the orbital moment. Magnetic structure is thus determined by spin-spin superexchange. In titanates, however, with much smaller Jahn-Teller distortions, orbital degeneracy might allow non-zero values of the orbital magnetic moment. Accordingly, novel forms of ferromagnetic superexchange interaction unique to t2g electrons systems have been theoretically predicted, although their experimental observation has remained elusive. Here we report a new kind of Ti3+ ferromagnetism at LaMnO3/SrTiO3 epitaxial interfaces. It results from charge transfer to the empty conduction band of the titanate and has spin and orbital contributions evidencing the role played by orbital degeneracy. The possibility of tuning magnetic alignment (ferromagnetic or antiferromagnetic) of Ti and Mn moments by structural parameters is demonstrated. This result will provide important clues for the understanding of the effects of orbital degeneracy in superexchange coupling.

  20. Self-assembled Ni/TiO{sub 2} nanocomposite anodes synthesized...

    Office of Scientific and Technical Information (OSTI)

    Ni(core)TiOsub 2(shell) nanocomposite anodes were fabricated on three-dimensional, self-assembled nanotemplates of Tobacco mosaic virus using atomic layer deposition, exhibiting ...

  1. Large oriented arrays and continuous films of TiO2 based nanotubes.

    SciTech Connect (OSTI)

    Xu, Huifang; Liu, Jun; Voigt, James A.; Tian, Zhengrong Ryan; McKenzie, Bonnie Beth

    2003-08-01

    We report for the first time a one-step, templateless method to directly prepare large arrays of oriented TiO{sub 2}-based nanotubes and continuous films. These titania nanostructures can also be easily prepared as conformal coatings on a substrate. The nanostructured films were formed on a Ti substrate seeded with TiO{sub 2} nanoparticles. SEM and TEM results suggested that a folding mechanism of sheetlike structures was involved in the formation of the nanotubes. The oriented arrays of TiO{sub 2} nanotubes, continuous films, and coatings are expected to have potentials for applications in catalysis, filtration, sensing, photovoltaic cells, and high surface area electrodes.

  2. Impact of symmetry on the ferroelectric properties of CaTiO3...

    Office of Scientific and Technical Information (OSTI)

    properties of CaTiO3 thin films Citation Details ... Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA Department of Materials Science ...

  3. Mechanisms of Oriented Attachment of TiO2 Nanocrystals in Vacuum...

    Office of Scientific and Technical Information (OSTI)

    Mechanisms of Oriented Attachment of TiO2 Nanocrystals in Vacuum and Humid Environments: Reactive Molecular Dynamics Citation Details In-Document Search Title: Mechanisms of ...

  4. Synthesis of Highly Ordered TiO2 Nanotubes Using Ionic Liquids for Photovoltaics Applications

    SciTech Connect (OSTI)

    2009-04-01

    This factsheet describes a study that deals with a new, green approach of synthesizing highly ordered TiO2 nanotubes using ionic liquids for photovoltaics (PV) applications.

  5. A nano lamella NbTi–NiTi composite with high strength

    SciTech Connect (OSTI)

    Jiang, Jiang; Jiang, Daqiang; Hao, Shijie; Yu, Cun; Zhang, Junsong; Ren, Yang; Lu, Deping; Xie, Shifang; Cui, Lishan

    2015-05-01

    A hypereutectic Nb60Ti24Ni16 (at%) alloy was prepared by vacuum induction melting, and a nano lamellae NbTi-NiTi composite was obtained by hot-forging and wire-drawing of the ingot Microscopic analysis showed that NbTi and NiTi nano lamellae distributed alternatively in the composite, and aligned along the wire axial direction, with a high volume fraction (similar to 70%) of NbTi nano lamellae. In situ synchrotron X-ray diffraction analysis revealed that stress induced martensitic transformation occurred upon loading, which would effectively weaken the stress concentration at the interface and avoid the introduction of defects into the nano reinforced phase. Then the embedded NbTi nano lamellae exhibited a high elastic strain up to 2.72%, 1.5 times as high as that of the Nb nanowires embedded in a conventional plastic matrix, and the corresponding stress carried by NbTi was evaluated as 2.53 GPa. The high volume fraction of NbTi nano lamellae improved the translation of high strength from the nano reinforced phase into bulk properties of the composite, with a platform stress of similar to 1.7 GPa and a fracture strength of similar to 1.9 GPa. (C) 2015 Elsevier B.V. All rights reserved.

  6. QUANTIFYING COMPOSITIONAL HOMOGENEITY IN Pb(ZrTi)O3 USING ATOM...

    Office of Scientific and Technical Information (OSTI)

    Title: QUANTIFYING COMPOSITIONAL HOMOGENEITY IN Pb(ZrTi)O3 USING ATOM PROBE TOMOGRAPHY. Abstract not provided. Authors: Ihlefeld, Jon F. ; Kotula, Paul Gabriel ; Brennecka, ...

  7. Investigation of carbon-coated lithiated Li{sub 4+x}Ti{sub 5...

    Office of Scientific and Technical Information (OSTI)

    and capacity retention. * TiOsub 2 nanoparticles and carbon coating are necessary for ... LITHIUM OXIDES; LITHIUM TITANATES; NANOPARTICLES; NANOSTRUCTURES; STABILITY; SYNTHESIS; ...

  8. Epitaxial Cr on n-SrTiO3(001)An ideal Ohmic contact

    SciTech Connect (OSTI)

    Capan, Cigdem; Sun, Guangyuan; Bowden, Mark E.; Chambers, Scott A.

    2012-01-30

    Epitaxial Cr metallizations grown on n-SrTiO3(001) by molecular beam epitaxy are shown to result in an ordered interface with Cr bound to O in the terminal TiO2 layer, no reduction of the SrTiO3, and a near-perfect Ohmic contact. Cr/n-SrTiO3(001) thus constitutes an ideal interface between a pure metal and wide gap oxide in which interface redox chemistry does not occur, and the Fermi level remains unpinned.

  9. Epitaxial Cr on n-SrTiO{sub 3}(001) - An ideal Ohmic contact

    SciTech Connect (OSTI)

    Capan, C.; Sun, G. Y.; Bowden, M. E.; Chambers, S. A.

    2012-01-30

    Epitaxial Cr metallizations grown on n-SrTiO{sub 3}(001) by molecular beam epitaxy are shown to result in an ordered interface with Cr bound to O in the terminal TiO{sub 2} layer, no reduction of the SrTiO{sub 3}, and a near-perfect Ohmic contact. Cr/n-SrTiO{sub 3}(001) thus constitutes an ideal interface between a pure metal and wide gap oxide in which interface redox chemistry does not occur, and the Fermi level remains unpinned.

  10. Features of a priori heavy doping of the n-TiNiSn intermetallic semiconductor

    SciTech Connect (OSTI)

    Romaka, V. A.; Rogl, P.; Romaka, V. V.; Hlil, E. K.; Stadnyk, Yu. V.; Budgerak, S. M.

    2011-07-15

    The crystal structure, the distribution of electron density, and the energy, kinetic, and magnetic properties of the n-TiNiSn intermetallic semiconductor are investigated. It is shown that a priori doping of n-TiNiSn with donors originates from partial, up to 0.5 at %, redistribution of Ti and Ni atoms in crystallographic sites of Ti atoms. The correlation is established between the donor concentration, amplitude of modulation of the continuous energy bands, and degree of filling of low-scale fluctuation potential wells with charge carriers. The results obtained are discussed within the Shklovskii-Efros model of a heavily doped and compensated semiconductor.

  11. Differences in chemical doping matter: Superconductivity in Ti1-xTaxSe2 but not in Ti1-xNbxSe2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Luo, Huixia; Zhu, Yimei; Xie, Weiwei; Tao, Jing; Pletikosic, Ivo; Valla, Tonica; Sahasrabudhe, Girija S.; Osterhoudt, Gavin; Sutton, Eric; Burch, Kenneth S.; et al

    2016-02-21

    We report that 1T-TiSe2, an archetypical layered transition metal dichalcogenide, becomes superconducting when Ta is substituted for Ti but not when Nb is substituted for Ti. This is unexpected because Nb and Ta should be chemically equivalent electron donors. Superconductivity emerges near x = 0.02 for Ti1–xTaxSe2, while, for Ti1–xNbxSe2, no superconducting transitions are observed above 0.4 K. The equivalent chemical nature of the dopants is confirmed by X-ray photoelectron spectroscopy. ARPES and Raman scattering studies show similarities and differences between the two systems, but the fundamental reasons why the Nb and Ta dopants yield such different behavior are unknown.more » We present a comparison of the electronic phase diagrams of many electron-doped 1T-TiSe2 systems, showing that they behave quite differently, which may have broad implications in the search for new superconductors. Here, we propose that superconducting Ti0.8Ta0.2Se2 will be suitable for devices and other studies based on exfoliated crystal flakes.« less

  12. The role of double TiO2 layers at the interface of FeSe/SrTiO3 superconductors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zou, Ke; Bozovic, Ian; Mandal, Subhasish; Albright, Stephen; Peng, Rui; Kumah, Divine; Simon, Georg; Dagdeviren, Omur; He, Xi; Schwarz, Udo; et al

    2016-05-16

    Here, we determine the surface reconstruction of SrTiO3 used to achieve superconducting FeSe films in experiments, which is different from the 1×1 TiO2-terminated SrTiO3 assumed by most previous theoretical studies. In particular, we identify the existence of a double TiO2 layer at the FeSe/SrTiO3 interface that plays two important roles. First, it facilitates the epitaxial growth of FeSe. Second, ab initio calculations reveal a strong tendency for electrons to transfer from an oxygen deficient SrTiO3 surface to FeSe when the double TiO2 layer is present. The double layer helps to remove the hole pocket in the FeSe at the Γmore » point of the Brillouin zone and leads to a band structure characteristic of superconducting samples. The characterization of the interface structure presented here is a key step towards the resolution of many open questions about this superconductor.« less

  13. In situ investigation of the early stage of TiO{sub 2} epitaxy on (001) SrTiO{sub 3}

    SciTech Connect (OSTI)

    Radovic, M.; Salluzzo, M.; Vaglio, R.; Granozio, F. Miletto; Ristic, Z.; Di Capua, R.; Lampis, N.

    2011-07-21

    We report on a systematic study of the growth of epitaxial TiO{sub 2} films deposited by pulsed laser deposition on Ti-terminated SrTiO{sub 3} (001) single crystals. By using in situ reflection high energy electron diffraction, low energy electron diffraction, x-ray photoemission spectroscopy, and scanning probe microscopy, we show that the stabilization of the anatase (001) phase is preceded by the growth of a few nanometers thick pseudomorphic Sr{sub x}TiO{sub 2+y} (x, y < 1) intermediate layer. The data demonstrate that the formation of this intermediate phase is related to the activation of a long range Sr migration from the SrTiO{sub 3} substrate into the film. Our results enrich the phase diagram of the Sr-Ti-O system under epitaxial strain opening a route for the study of the electronic and dielectric properties of the reported Sr-deficient SrTiO{sub 3} phase.

  14. A novel 3D structure composed of strings of hierarchical TiO{sub 2} spheres formed on TiO{sub 2} nanobelts with high photocatalytic properties

    SciTech Connect (OSTI)

    Jiang, Yongjian; Li, Meicheng; Song, Dandan; Li, Xiaodan; Yu, Yue

    2014-03-15

    A novel hierarchical titanium dioxide (TiO{sub 2}) composite nanostructure with strings of anatase TiO{sub 2} hierarchical micro-spheres and rutile nanobelts framework (TiO{sub 2} HSN) is successfully synthesized via a one-step hydrothermal method. Particularly, the strings of hierarchical spheres are assembled by very thin TiO{sub 2} nanosheets, which are composed of highly crystallized anatase nanocrystals. Meanwhile, the HSN has a large surface area of 191 m{sup 2}/g, which is about 3 times larger than Degussa P25. More importantly, the photocatalytic activity of HSN and P25 were evaluated by the photocatalytic oxidation decomposition of methyl orange (MO) under UV light illumination, and the TiO{sub 2} HSN shows enhanced photocatalytic activity compared with Degussa P25, as result of its continuous hierarchical structures, special conductive channel and large specific surface area. With these features, the hierarchical TiO{sub 2} may have more potential applications in the fields of dye-sensitized solar cells and lithium ion batteries. -- Graphical abstract: Novel TiO{sub 2} with anatase micro-spheres and rutile nanobelts is synthesized. Enhanced photocatalysis is attributed to hierarchical structures (3D spheres), conductive channel (1D nanobelts) and large specific surface area (2D nanosheet). Highlights: • The novel TiO{sub 2} nanostructure (HSN) is fabricated for the first time. • HSN is composed of strings of anatase hierarchical spheres and rutile nanobelt. • HSN presents a larger S{sub BET} of 191 m{sup 2}/g, 3 times larger than the Degussa P25 (59 m{sup 2}/g). • HSN owns three kinds of dimensional TiO{sub 2} (1D, 2D and 3D) simultaneously. • HSN exhibits better photocatalytic performance compared with Degussa P25.

  15. Solar photocatalytic activities of porous Nb-doped TiO{sub 2} microspheres by coupling with tungsten oxide

    SciTech Connect (OSTI)

    Kou, Yanqiang; Yang, Jikai; Li, Bing; Fu, Shencheng

    2015-03-15

    Highlights: Nb-TiO{sub 2}/WO{sub 3} was prepared by USP method combined impregnation method. Nb-doping extend the spectral absorption of TiO{sub 2} into visible spectrum. Nb-TiO{sub 2}/WO{sub 3} has a similar optical band gap as Nb-TiO{sub 2}. PL spectra indicate WO{sub 3} can accept the photoexcited electrons from Nb-TiO{sub 2}. Nb-TiO{sub 2}/WO{sub 3} shows higher activity than TiO{sub 2} and Nb-TiO{sub 2} under solar light. - Abstract: Nb doped TiO{sub 2} microspheres modified with WO{sub 3} (Nb-TiO{sub 2}/WO{sub 3}) was prepared by ultrasonic spray pyrolysis method combined with impregnation method. The microspheres were characterized with SEM, TEM, XRD, BET, photoluminescence and UVvis absorption spectra. The Nb-doping was observed to extend the spectral absorption of TiO{sub 2} into visible spectrum, and the absorption onset was red-shifted for about 88 nm compared to pristine TiO{sub 2} microspheres. Nb-TiO{sub 2}/WO{sub 3} microspheres do not display a red-shifted absorption edge compared with Nb doped TiO{sub 2} microspheres. Under solar irradiation, Nb-TiO{sub 2}/WO{sub 3} microspheres showed higher photocatalytic activity for methylene blue degradation compared with that of pure TiO{sub 2} microspheres and Nb doped TiO{sub 2} microspheres, which could be ascribed to the extended light absorption range and the suppression of electron-hole pair recombination.

  16. Pb{sub 5}Fe{sub 3}TiO{sub 11}Cl: A rare example of Ti(IV) in a square pyramidal oxygen coordination

    SciTech Connect (OSTI)

    Batuk, Maria; Batuk, Dmitry; Abakumov, Artem M.; Hadermann, Joke

    2014-07-01

    A new oxychloride Pb{sub 5}Fe{sub 3}TiO{sub 11}Cl has been synthesized using the solid state method. Its crystal and magnetic structure was investigated in the 1.5550 K temperature range using electron diffraction, high angle annular dark field scanning transmission electron microscopy, atomic resolution energy dispersive X-ray spectroscopy, neutron and X-ray powder diffraction. At room temperature Pb{sub 5}Fe{sub 3}TiO{sub 11}Cl crystallizes in the P4/mmm space group with the unit cell parameters a=3.91803(3) and c=19.3345(2) . Pb{sub 5}Fe{sub 3}TiO{sub 11}Cl is a new n=4 member of the oxychloride perovskite-based homologous series A{sub n+1}B{sub n}O{sub 3n?1}Cl. The structure is built of truncated Pb{sub 3}Fe{sub 3}TiO{sub 11} quadruple perovskite blocks separated by CsCl-type Pb{sub 2}Cl slabs. The perovskite blocks consist of two layers of (Fe,Ti)O{sub 6} octahedra sandwiched between two layers of (Fe,Ti)O{sub 5} square pyramids. The Ti{sup 4+} cations are preferentially located in the octahedral layers, however, the presence of a noticeable amount of Ti{sup 4+} in a five-fold coordination environment has been undoubtedly proven using neutron powder diffraction and atomic resolution compositional mapping. Pb{sub 5}Fe{sub 3}TiO{sub 11}Cl is antiferromagnetically ordered below 450(10) K. The ordered Fe magnetic moments at 1.5 K are 4.06(4) ?{sub B} and 3.86(5) ?{sub B} on the octahedral and square-pyramidal sites, respectively. - Highlights: Pb{sub 5}Fe{sub 3}TiO{sub 11}Cl has been synthesized using the solid state method. The structure has been refined using neutron powder diffraction data at 1.5550 K. It is a new n=4 member of the perovskite-related homologous series A{sub n+1}B{sub n}O{sub 3n?1}Cl. Ti{sup 4+} cations have both octahedral and square-pyramidal coordination environment. Pb{sub 5}Fe{sub 3}TiO{sub 11}Cl is antiferromagnetically ordered below T{sub N}?450 K.

  17. Structural and spectroscopic properties of high temperature prepared ZrO₂–TiO₂ mixed oxides

    SciTech Connect (OSTI)

    Gionco, Chiara; Battiato, Alfio; Vittone, Ettore; Paganini, Maria Cristina; Giamello, Elio

    2013-05-01

    ZrO₂-TiO₂ mixed oxides of various composition, with the molar fraction of TiO₂ ranging from 0.1% to 15%, have been prepared via sol-gel synthesis and then calcined at 1273 K to check both their thermal stability and physicochemical properties. These solids are usually employed in photocatalytic processes and as active phase supports in heterogeneous catalysis. As indicated by X-ray diffraction and Raman spectroscopy, solid solutions based on Ti ions diluted in the ZrO₂ matrix are formed in the whole range of Ti molar fraction examined. Materials with low Ti loading (0.1%–1%) are basically constituted by the monoclinic phase of ZrO₂ while the tetragonal phase becomes prevalent at 15% of TiO₂ molar fraction. The presence of Ti ions modify the electronic structure of the solid as revealed by investigation of the optical properties. The typical band gap transition of ZrO₂ undergoes, in fact, a red shift roughly proportional to the Ti loading which reach the remarkable value of 1.6 eV for the sample with 10% of molar Ti concentration. Comparing chemical analysis of the solids with XPS data it has been put into evidence that the titanium ions distribution into the solid is not uniform and the concentration of Ti⁴⁺ tend to be higher in subsurface layers than in the crystal bulk. The introduction of titanium ions in the structure increases the reducibility of the solid. Annealing under vacuum at various temperatures causes oxygen depletion with consequent reduction of the solid which shows up mainly in terms of formation of Ti³⁺ reduced centres which are characterized by a typical EPR signal. Ti³⁺ defects forms, as also forecast by theoretical modelling of the solid, as their energy is lower than that of other possible reduced defective centers. The reduced solids are able to transfer electrons to adsorbed oxygen molecules in mild condition resulting in the formation of surface superoxide anions (O₂⁻) which are stabilized on surface Zr

  18. Effect of different processes and Ti/Zn molar ratios on the structure, morphology, and enhanced photoelectrochemical and photocatalytic performance of Ti3+ self-doped titanium–zinc hybrid oxides

    SciTech Connect (OSTI)

    Fu, Rongrong; Wang, Qingyao; Gao, shanmin; Wang, Zeyan; Huang, Baibiao; Dai, Ying; Lu, Jun

    2015-07-01

    Ti3+ self-doped titanium–zinc hybrid oxides with different phase compositions and morphologies were successfully synthesized using Zn powder as the reductant and Zn source by a chemical-reduction precipitation method with subsequent thermal treatment. The fabricated Ti3+ self-doped TiO2(A)/TiO2(R), TiO2(A)/TiO2(R)/ZnTiO3, and TiO2(A)/ZnO heterojunctions were characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and UV–Vis diffuse reflectance spectroscopy. The effects of various Ti/Zn molar ratios and preparation processes on the structural, morphological, optical, photocurrent and photocatalytic properties of the resultant samples were investigated systematically. Results reveal that Ti3+ self-doping enhances the photoabsorption capability of titanium–zinc hybrid oxides in the visible-light region. Moreover, different processes and Ti/Zn molar ratios play great influences on the structure, morphology, optical, photocurrent and photocatalytic properties of the final products. Ti3+ self-doped titanium–zinc hybrid oxides exhibit excellent photocurrent and photocatalytic activity than pure TiO2 and ZnTiO3 under visible-light irradiation (λ ≥ 400 nm). The most active Ti3+ self-doped titanium–zinc hybrid oxides photoanode presents significantly improved water splitting performance. The synergistic effect between the Ti3+ self-doped and heterojunctions is responsible for the enhanced performance of these materials.

  19. Visible light photocatalytic degradation of 4-chlorophenol using vanadium and nitrogen co-doped TiO{sub 2}

    SciTech Connect (OSTI)

    Jaiswal, R.; Kothari, D. C.; Patel, N.; Miotello, A.

    2013-02-05

    Vanadium and Nitrogen were codoped in TiO{sub 2} photocatalyst by Sol-gel method to utilize visible light more efficiently for photocatalytic reactions. A noticeable shift of absorption edge to visible light region was obtained for the singly-doped namely V-TiO{sub 2}, N-TiO{sub 2} and codoped V-N-TiO{sub 2} samples in comparison with undoped TiO{sub 2}, with smallest band gap obtained with codoped-TiO{sub 2}. The photocatalytic activities for all TiO{sub 2} photocatalysts were tested by 4-chlorophenol (organic pollutant) degradation under visible light irradiation. It was found that codoped TiO{sub 2} exhibits the best photocatalytic activity, which could be attributed to the synergistic effect produced by V and N dopants.

  20. Epitaxial single-crystal thin films of MnxTi1-xO2-δ grown on...

    Office of Scientific and Technical Information (OSTI)

    on (rutile)TiO2 substrates with pulsed laser deposition: Experiment and theory Citation ... on (rutile)TiO2 substrates with pulsed laser deposition: Experiment and theory ...

  1. DE-FC26-06NT42877 - DE-FC26-02NT41628 - DE-FC26-00NT40920 | netl...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... near-sea-floor geology from large volumes of 4-component ocean-bottom cable seismic data. Acoustic "wipe-out" zones, evident on chirp sonar records from MC 118 are not indicative ...

  2. High temperature tensile properties of V-4Cr-4Ti

    SciTech Connect (OSTI)

    Zinkle, S.J.; Rowcliffe, A.F.; Stevens, C.O.

    1998-09-01

    Tensile tests have been performed on V-4Cr-4Ti at 750 and 800 C in order to extend the data base beyond the current limit of 700 C. From comparison with previous measurements, the yield strength is nearly constant and tensile elongations decrease slightly with increasing temperature between 300 and 800 C. The ultimate strength exhibits an apparent maximum near 600 C (attributable to dynamic strain aging) but adequate strength is maintained up to 800 C. The reduction in area measured on tensile specimens remained high ({approximately}80%) for test temperatures up to 800 C, in contrast to previous reported results.

  3. Injection mode-locking Ti-sapphire laser system

    DOE Patents [OSTI]

    Hovater, James Curtis; Poelker, Bernard Matthew

    2002-01-01

    According to the present invention there is provided an injection modelocking Ti-sapphire laser system that produces a unidirectional laser oscillation through the application of a ring cavity laser that incorporates no intracavity devices to achieve unidirectional oscillation. An argon-ion or doubled Nd:YVO.sub.4 laser preferably serves as the pump laser and a gain-switched diode laser serves as the seed laser. A method for operating such a laser system to produce a unidirectional oscillating is also described.

  4. HNF-SD-WM-TI-740, Rev. OA

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    84045. HNF-SD-WM-TI-740, Rev. OA Standard Inventories of Chemicals and Radionuclides in Hanford Site Ta nk Wastes M. J. Kupfer, A. L. Boldt, B. A. Higley, K. M. Hodgson, L. W. Shelton, B. C. Simpson, and R. A. Watrous (LMHC); M. 0. LeClair (SAIC); G. 1. Borsheim (BA); R. T. Winward (MA); R. M. Orme (NHC); N. 6. Colton (PNNL); S. 1. Lambert and D. E. Place (SESC); and W. W. SchulZ (W 2 S) Lockheed Martin Hanford Corporation, Richland, WA 99352 U.S. Department of Energy Contract DE-AC06-96RL13200

  5. HNF-SD-WM-TI-740, Rev. OC

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    84047 HNF-SD-WM-TI-740, Rev. OC Standard Inventories of Chemicals and Radionuclides in Hanford Site Tank Wastes M. J. Kupfer, A. L. Boldt, K. N. Hodgson, L. W. Shelton, B. C. Simpson, and R. A. Watrous (LMHC); M. D. LeClair (SAIC); G. 1. Borsheim (BA); R. T. Winward (MA); B. A. Higley and R. M. Orme (NHC); N. G. Colton (PNNL); S. L. Lambert and D. E. Place (Cogema); and W. W. Schulz (112S) Lockheed Martin Hanford Corporation, Richland, WA 99352 U.S. Department of Energy Contract

  6. Stable atomic structure of NiTi austenite

    SciTech Connect (OSTI)

    Zarkevich, Nikolai A; Johnson, Duane D

    2014-08-01

    Nitinol (NiTi), the most widely used shape-memory alloy, exhibits an austenite phase that has yet to be identified. The usually assumed austenitic structure is cubic B2, which has imaginary phonon modes, hence it is unstable. We suggest a stable austenitic structure that on average has B2 symmetry (observed by x-ray and neutron diffraction), but it exhibits finite atomic displacements from the ideal B2 sites. The proposed structure has a phonon spectrum that agrees with that from neutron scattering, has diffraction spectra in agreement with x-ray diffraction, and has an energy relative to the ground state that agrees with calorimetry data.

  7. Ferroelectric-like response from the surface of SrTiO₃ crystals at high temperatures

    SciTech Connect (OSTI)

    Jyotsna, Shubhra; Arora, Ashima; Sekhon, Jagmeet S.; Sheet, Goutam

    2014-09-14

    Since SrTiO₃ has a high dielectric constant, it is used as a substrate for a large number of complex physical systems for electrical characterization. Since SrTiO₃ crystals are known to be non-ferroelectric/non-piezoelectric at room temperature and above, SrTiO₃ has been believed to be a good choice as a substrate/base material for PFM (Piezoresponse Force Microscopy) on novel systems at room temperature. In this paper, from PFM-like measurement using an atomic force microscope on bare crystals of (110) SrTiO₃ we show that ferroelectric and piezoelectric-like response may originate from bare SrTiO₃ at remarkably high temperatures up to 420 K. Electrical domain writing and erasing are also possible using a scanning probe tip on the surface of SrTiO₃ crystals. This observation indicates that the role of the electrical response of SrTiO₃ needs to be revisited in the systems where signature of ferroelectricity/piezoelectricity has been previously observed with SrTiO₃ as a substrate/base material.

  8. Preparation and properties of ce-doped TiO{sub 2} photocatalyst

    SciTech Connect (OSTI)

    Yan, Ningning; Zhu, Zhongqi; Zhang, Jin; Zhao, Zongyan; Liu, Qingju

    2012-08-15

    Highlights: ? The cerium ion doped TiO{sub 2} (Ce-TiO{sub 2}) powders were prepared and characterized. ? The spectrum absorption region of Ce-TiO{sub 2} is red-shifted to visible light. ? The recombination of photo-generated electron-hole pairs of Ce-TiO{sub 2} is inhibited. ? The photocatalytic activity was effected by Ce ion content and greatly improved. -- Abstract: TiO{sub 2} nanoparticles doped with different content of Ce ion were prepared by solgel method. The samples were characterized by XRD, XPS, TEM, UVVis, and PL, the photocatalytic activity was evaluated by photocatalytic degradation of methylene blue (MB) under the irradiation of fluorescent lamp. The results indicate that Ce ion is incorporated into the lattice of TiO{sub 2}, which can restrain the increase of grain size, broaden the absorption region to visible light, and inhibit the recombination of the photo-generated electron and hole pairs. Moreover, the photocatalytic activity of Ce-TiO{sub 2} in MB degradation is evidently enhanced. The MB degradation rate of the sample with Ce:Ti = 0.33% (molar ratio) in 8 h is 90.03%, which is much higher than that of P25 (68.19%).

  9. An Experimental and Theoretical Multi-Mbar Study of Ti-6Al-4V

    SciTech Connect (OSTI)

    Tegner, B E; Macleod, S G; CYNN, H; Proctor, J; Evans, W J; McMahon, M I; Ackland, G J

    2011-04-13

    We report results from an experimental and theoretical study of the room temperature (RT) compression of the ternary alloy Ti-6Al-4V. In this work, we have extended knowledge of the equation of state (EOS) from 40 GPa to 221 GPa, and observed a different sequence of phase transitions to that reported previously for pure Ti.

  10. Stoichiometric growth of SrTiO3 films by sequential pulsed laser deposition from SrO and TiO2 targets

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Herklotz, A; Dorr, Kathrin; Biegalski, Michael D

    2015-01-01

    We report the growth of stoichiometric SrTiO3 films by sequential pulsed laser deposition from SrO and TiO2 targets. In-situ reflection high-energy electron diffraction is used to control the growth and achieve films with excellent structural quality. The growth shows similarities to the case of molecular beam epitaxy of SrTiO3 from Sr and Ti sources. In order to further demonstrate the capability of the approach, we grow artificial Srn+1TinO3n+1 Ruddlesden-Popper phases with n = 2 and 3. Our result has potential to be extendable to other perovskite-type oxides, enabling one to grow epitaxial films with improved structural quality and electronic functionality.

  11. Enhanced hardness in epitaxial TiAlScN alloy thin films and rocksalt TiN/(Al,Sc)N superlattices

    SciTech Connect (OSTI)

    Saha, Bivas; Lawrence, Samantha K.; Bahr, David F.; Schroeder, Jeremy L.; Birch, Jens; Sands, Timothy D.

    2014-10-13

    High hardness TiAlN alloys for wear-resistant coatings exhibit limited lifetimes at elevated temperatures due to a cubic-AlN to hexagonal-AlN phase transformation that leads to decreasing hardness. We enhance the hardness (up to 46 GPa) and maximum operating temperature (up to 1050 °C) of TiAlN-based coatings by alloying with scandium nitride to form both an epitaxial TiAlScN alloy film and epitaxial rocksalt TiN/(Al,Sc)N superlattices on MgO substrates. The superlattice hardness increases with decreasing period thickness, which is understood by the Orowan bowing mechanism of the confined layer slip model. These results make them worthy of additional research for industrial coating applications.

  12. Structural properties of Ge on SrTiO{sub 3} (001) surface and Ge/SrTiO{sub 3} interface

    SciTech Connect (OSTI)

    Pu, Long; Wang, Jianli Tang, Gang; Zhang, Junting

    2015-03-14

    Germanium−perovskite oxide heterostructures have a strong potential for next-generation low-voltage and low-leakage metal-oxide semiconductor field-effect transistors. We investigated the atomic structure and electronic properties of Ge on perfect and defective (001) SrTiO{sub 3} by first-principle calculations. The specific adsorption sites at the initial growth stage and the atomic structure of Ge on the SrTiO{sub 3} (001) substrate have been systematically investigated. The surface grand potential was calculated and compared as a function of the relative chemical potential. The complete surface phase diagram was presented. The energetically favorable interfaces were pointed out among the atomic arrangements of the Ge/SrTiO{sub 3} (001) interfaces. The atomic structure and electronic properties of the intrinsic point defects were calculated and analyzed for the Ge/SrTiO{sub 3} (001) interfaces.

  13. TiO{sub 2} nanorods branched on fast-synthesized large clearance TiO{sub 2} nanotube arrays for dye-sensitized solar cells

    SciTech Connect (OSTI)

    Hu Anzheng; Li Haina; Jia Zhiyong; Xia Zhengcai

    2011-11-15

    A large clearance TiO{sub 2} nanotube arrays (LTAs) has been synthesized by a not more than 12 h anodization duration and based on this a branched TiO{sub 2} nanotube arrays (BLTs) has been achieved through TiO{sub 2} nanorods branch-like grown on the LTAs. Some key factors and probable mechanisms of the fabrication processes on two novel nanoarchitectures are discussed. Exhilaratingly, it is found that the obtained LTAs has demonstrated large pore diameter and void spaces (pore diameter {approx}350 nm; void spaces {approx}160 nm; and tube length {approx}3.5 {mu}m), and the synthesized hierarchical BLTs, compared with conventional TiO{sub 2} nanotube arrays, has shown a much stronger dye absorption performance and an approximately double of the solar cell efficiency (in our case from 1.62% to 3.18% under simulated AM 1.5 conditions). - Graphical Abstract: The schematic diagram of synthesis process for LTAs and BLTs is on the above and the corresponding FESEM images of obtained photoanodes samples are shown below. Highlights: > Large clearance TiO{sub 2} nanotube arrays (LTAs) was synthesized by a fast anodization process of 12 h. > Anodization time of 12 h is just 10% of about 120 h reported in the previous references. > Branch-like TiO{sub 2} nanotube arrays (BLTs) was achieved by growing TiO{sub 2} nanorods on the LTAs. > Obtained BLTs and LTAs show impressive morphology and noticeable improvement of surface area. > BLTs shows about more than 1 times higher solar cell efficiency than that of TiO{sub 2} nanotube arrays.

  14. TiN/VN composites with core/shell structure for supercapacitors

    SciTech Connect (OSTI)

    Dong, Shanmu; Chen, Xiao; Gu, Lin; Zhou, Xinhong; Wang, Haibo; Liu, Zhihong; Han, Pengxian; Yao, Jianhua; Wang, Li; Cui, Guanglei; Chen, Liquan; Institute of Physics, Chinese Academy of Sciences, Beijing 100080

    2011-06-15

    Research highlights: {yields} Vanadium and titanium nitride nanocomposite with core-shell structure was prepared. {yields} TiN/VN composites with different V:Ti molar ratios were obtained. {yields} TiN/VN composites can provide promising electronic conductivity and favorable capacity storage. -- Abstract: TiN/VN core-shell composites are prepared by a two-step strategy involving coating of commercial TiN nanoparticles with V{sub 2}O{sub 5}.nH{sub 2}O sols followed by ammonia reduction. The highest specific capacitance of 170 F g{sup -1} is obtained when scanned at 2 mV s{sup -1} and a promising rate capacity performance is maintained at higher voltage sweep rates. These results indicate that these composites with good electronic conductivity can deliver a favorable capacity performance.

  15. Nanocrystalline BaTiO3 powder via ambient conditions sol process (Prop.2001-071)

    SciTech Connect (OSTI)

    Payzant, E Andrew; Wang, X.; Hu, Michael Z.; Blom, Douglas Allen

    2005-01-01

    Nanocrystalline BaTiO{sub 3} particles have been prepared by ambient condition sol (ACS) process starting from soluble precursors of barium and titanium yielding a mixed oxide/hydroxide gel. The gel was peptized and crystallized in water under a refluxing condition. Higher initial pH and Ba/Ti ratio led to smaller crystallite sizes of BaTiO{sub 3} powders. Organic mineralizer, tetramethylammonium hydroxide (TMAH), can adsorb on the BaTiO{sub 3} nuclei and inhibited further growth of the particles. Adding a polymer during BaTiO{sub 3} synthesis led to a smaller particle size and increased redispersibility of the particles in water.

  16. Structural Study And Optical Properties Of TiO{sub 2} Thin Films Elaborated By Thermal Oxidation Of RF Magnetron Sputtered Ti Films

    SciTech Connect (OSTI)

    Guitoume, D.; Achour, S.; Guittoum, A.; Abaidia, S. E. H.

    2008-09-23

    We report on the effect of thickness on the structural and optical properties of TiO{sub 2} thin films obtained by direct exposure of Ti metal film to thermal oxidation. Ti thin films with thicknesses ranging from 87 nm to 484 nm were deposited onto glass substrate by RF magnetron sputtering. Thereafter, the as-deposited Ti films were annealed in air at temperature equal to 520 deg. C. The structural evolution and optical properties of obtained TiO{sub 2} films were studied by means of Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM) and UV-Visible spectroscopy. The films thicknesses were extracted from RBS spectra. From X-ray diffraction spectra, we can see that all the films present three TiO{sub 2} phases (anatase, rutile and Brookite). The anatase and rutile phases exhibit a strong preferred orientation along (004) and (210) planes respectively. The grain sizes, D (nm), did not change much with increasing thickness. The average value of (nm) was equal to 29 nm for anatase and 26 nm for rutile. The micrographs taken from SEM experiments indicate that the films present a dense micro structure with very small grains. Transmittance spectra show that all the films present a good transparency in the visible region. The dependence of transmittance, optical band gap and refractive index on the thickness of the films was also studied.

  17. Active wear and failure mechanisms of TiN-coated high speed steel and TiN-coated cemented carbide tools when machining powder metallurgically made stainless steels

    SciTech Connect (OSTI)

    Jiang, L.; Haenninen, H.; Paro, J.; Kauppinen, V.

    1996-09-01

    In this study, active wear and failure mechanisms of both TiN-coated high speed steel and TiN-coated cemented carbide tools when machining stainless steels made by powder metallurgy in low and high cutting speed ranges, respectively, have been investigated. Abrasive wear mechanisms, fatigue-induced failure, and adhesive and diffusion wear mechanisms mainly affected the tool life of TiN-coated high speed steel tools at cutting speeds below 35 m/min, between 35 and 45 m/min, and over 45 m/min, respectively. Additionally, fatigue-induced failure was active at cutting speeds over 45 m/min in the low cutting speed range when machining powder metallurgically made duplex stainless steel 2205 and austenitic stainless steel 316L. In the high cutting speed range, from 100 to 250 m/min, fatigue-induced failure together with diffusion wear mechanism, affected the tool life of TiN-coated cemented carbide tools when machining both 316L and 2205 stainless steels. It was noticed that the tool life of TiN-coated high speed steel tools used in the low cutting speed range when machining 2205 steel was longer than that when machining 316L steel, whereas the tool life of TiN-coated cemented carbide tools used in the high cutting speed range when machining 316L steel was longer than that when machining 2205 steel.

  18. Revealing the atomic and electronic structure of a SrTiO{sub 3}/LaNiO{sub 3}/SrTiO{sub 3} heterostructure interface

    SciTech Connect (OSTI)

    Zhang, Zaoli; Soltan, S.; Schmid, H.; Habermeier, H.-U.; Keimer, B.; Kaiser, U.

    2014-03-14

    The atomic structures of SrTiO{sub 3} (STO)/LaNiO{sub 3} (LNO)/STO heterostructure interfaces were investigated by spherical aberration-corrected (C{sub S}) (scanning) transmission electron microscopy. Atomic displacement and lattice distortion measurements and electron energy loss spectroscopy (EELS) were used to quantitatively analyze the distortion of the interfacial octahedra and the bond length at the interfaces. Combined with high-resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy analyses, two distinct interfacial atomic terminating layers are unambiguously determined. Ensuing quantitative HRTEM measurements revealed that the Ni-O bond length in the interfacial octahedral is elongated at the bottom interface (NiO{sub 2}-SrO). Atomic displacement shows structural relaxation effects when crossing the interfaces and lattice distortions across the interface is more pronounced in LNO than in STO. The Ti/O atomic ratio, La and Ti relative atomic ratio as derived by EELS quantification indicate non-stoichiometric composition at the interfaces. Distinct fine structures of Ti-L{sub 2,3} edge and O-K edge at the bottom and top interfaces are observed. By comparison, we are able to estimate Ti valency at both interfaces. Combining the structural distortions and Ti valency, the polar discontinuity and charge transfer at the interfaces are discussed.

  19. Preparation and lithium intercalation behavior of TiO{sub 2} in aqueous solutions

    SciTech Connect (OSTI)

    Li, Yunjiao, E-mail: yunjiaoli6601@hotmail.com; Li, Lin; Chen, Lingpeng; Wang, Xuanyu; Xu, Cang

    2014-04-01

    Highlights: The poor crystalline anatase phase or amorphous TiO{sub 2} was prepared by TiCl{sub 4} hydrolysis under different pH conditions. Phase transition behavior and lithium intercalation ability of the obtained TiO{sub 2} were found to be related to TiO{sub 2} property. The results indicate that TiO{sub 2} products obtained from TiCl{sub 4} hydrolysis at lower pH are favorable for lithium intercalation. - Abstract: The low crystalline or amorphous TiO{sub 2} was prepared by TiCl{sub 4} hydrolysis in aqueous solutions under different pH conditions at 45 C. The products obtained at lower pH (1.233.10) appear to be nano-sized particles with poor crystalline anatase structure and an uniform particle size distribution, while the product prepared at pH 4.10 presents in a poor crystalline anatase structure and the regular morphology starts to disappear, and the products obtained at higher pH (>6.00) are amorphous and irregular morphology. The hydrolysis products obtained at pH 2.60 and 8.80 were heat-treated at 300, 400, 600, 700 and 800 C for 3 h, respectively, to figure out the phase transition. The differences in phase transition process were observed, which verified the properties difference. The lithium intercalation abilities of the obtained TiO{sub 2} were studied. The results indicated that the TiO{sub 2} obtained at lower pH are more favorable for lithium intercalation and are better precursors.

  20. Fabrication and characterization of photovoltaic devices based on perovskite compounds with TiO{sub 2} nanoparticles

    SciTech Connect (OSTI)

    Kanayama, Masato Oku, Takeo Suzuki, Atsushi; Yamada, Masahiro; Sakamoto, Hiroki; Fukunishi, Sakiko; Kohno, Kazufumi

    2015-02-27

    Perovskite-type photovoltaic devices were fabricated by a spin-coating method using a mixture solution. The compact and meso-porous TiO{sub 2} of the solar cells were fabricated from TiO{sub 2} nanoparticles and sol, and the photovoltaic properties and microstructures were characterized. The conversion efficiencies were improved by the combination of TiO{sub 2} nanoparticles and sol. Current density was also improved by increasing numbers of spin-coatings of meso-porous TiO{sub 2}. Thick meso-porous TiO2 layers would assist the construction of perovskite layers and block of the leak current.

  1. Brazing ZrO{sub 2} ceramic to Ti6Al4V alloy using NiCrSiB amorphous filler foil: Interfacial microstructure and joint properties

    SciTech Connect (OSTI)

    Cao, J., E-mail: cao_jian@hit.edu.cn [Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Song, X.G., E-mail: song_xiaoguohit@yahoo.com.cn [Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Li, C., E-mail: li_chun1989@yahoo.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Zhao, L.Y., E-mail: Zhao_ly@163.com [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Feng, J.C., E-mail: feng_jicai@163.com [Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China)

    2013-07-15

    Reliable brazing of ZrO{sub 2} ceramic and Ti6Al4V alloy was achieved using NiCrSiB amorphous filler foil. The interfacial microstructure of ZrO{sub 2}/Ti6Al4V joints was characterized by scanning electron microscope, energy dispersive spectrometer and micro-focused X-ray diffractometer. The effects of brazing temperature on the interfacial microstructure and joining properties of brazed joints were investigated in detail. Active Ti of Ti6Al4V alloy dissolved into molten filler metal and reacted with ZrO{sub 2} ceramic to form a continuous TiO reaction layer, which played an important role in brazing. Various reaction phases including Ti{sub 2}Ni, Ti{sub 5}Si{sub 3} and ?-Ti were formed in brazed joints. With an increasing of brazing temperature, the TiO layer thickened gradually while the Ti{sub 2}Ni amount reduced. Shear test indicated that brazed joints tend to fracture at the interface between ZrO{sub 2} ceramic and brazing seam or Ti{sub 2}Ni intermetallic layer. The maximum average shear strength reached 284.6 MPa when brazed at 1025 C for 10 min. - Graphical Abstract: Interfacial microstructure of ZrO{sub 2}/TC4 joint brazed using NiCrSiB amorphous filler foil was: ZrO{sub 2}/TiO/Ti{sub 2}Ni + ?-Ti + Ti{sub 5}Si{sub 3}/?-Ti/Widmansttten structure/TC4. - Highlights: Brazing of ZrO{sub 2} ceramic and Ti-6Al-4V alloy was achieved. Interfacial microstructure was TiO/Ti{sub 2}Ni + ? + Ti{sub 5}Si{sub 3}/?/Widmansttten structure. The formation of TiO produced the darkening effect of ZrO{sub 2} ceramic. The highest joining strength of 284.6MPa was obtained.

  2. Graphene oxide modified TiO2 nanotube arrays?enhanced visible light photoelectrochemical properties

    SciTech Connect (OSTI)

    Song, Peng; Zhang, Xiao-Yan; Sun, Mingxun; Cui, Xiao-Li; Lin, Yuehe

    2012-03-01

    Novel nanocomposite films based on graphene oxide (GO) and TiO{sub 2} nanotube arrays were synthesized by assembling GO on the surface of self-organized TiO{sub 2} nanotube arrays through a simple assembling method. The composite films were characterized with field emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and UV-vis diffuse reflectance spectroscopy. Photoelectrochemical properties of the composite nanotube arrays were investigated under visible light illumination. Remarkably enhanced visible light photoelectrochemical response was observed for the GO decorated TiO{sub 2} nanotube composite electrode compared with pristine TiO{sub 2} nanotube arrays. Sensitizing effect of GO on the photoelectrochemical response of TiO{sub 2} nanotube arrays was demonstrated and about 15 times enhanced maximum photoconversion efficiency was obtained with the presence of GO. Enhanced photocatalytic activity of TiO{sub 2} nanotube arrays towards degradation of methyl blue was also demonstrated after modification of GO. The results presented here demonstrate GO to be efficient for the improvement of utilization of visible light for TiO{sub 2} nanotube arrays.

  3. Location Of Hole And Electron Traps On Nanocrystalline Anatase TiO2

    SciTech Connect (OSTI)

    Mercado, Candy C.; Knorr, Fritz J.; McHale, Jeanne L.; Usmani, Shirin M.; Ichimura, Andrew S.; Saraf, Laxmikant V.

    2012-05-17

    The defect photoluminescence from TiO2 nanoparticles in the anatase phase is reported for nanosheets which expose predominantly (001) surfaces, and compared to that from conventional anatase nanoparticles which expose mostly (101) surfaces. Also reported is the weak defect photoluminescence of TiO2 nanotubes, which we find using electron back-scattered diffraction to consist of walls which expose (110) and (100) facets. The nanotubes exhibit photoluminescence that is blue-shifted and much weaker than that from conventional TiO2 nanoparticles. Despite the preponderance of (001) surfaces in the nanosheet samples, they exhibit photoluminescence similar to that of conventional nanoparticles. We assign the broad visible photoluminescence of anatase nanoparticles to two overlapping distributions: hole trap emission associated with oxygen vacancies on (101) exposed surfaces, which peaks in the green, and a broader emission extending into the red which results from electron traps on under-coordinated titanium atoms, which are prevalent on (001) facets. The results of this study suggest how morphology of TiO2 nanoparticles could be optimized to control the distribution and activity of surface traps. Our results also shed light on the mechanism by which the TiCl4 surface treatment heals traps on anatase and mixed-phase TiO2 films, and reveals distinct differences in the trap-state distributions of TiO2 nanoparticles and nanotubes. The molecular basis for electron and hole traps and their spatial separation on different facets is discussed.

  4. Direct Evidence of Lithium-Induced Atomic Ordering in Amorphous TiO2 Nanotubes

    SciTech Connect (OSTI)

    Gao, Qi; Gu, Meng; Nie, Anmin; Mashayek, Farzad; Wang, Chong M.; Odegard, Gregory M.; Shahbazian-Yassar, Reza

    2014-01-27

    In this paper, we report the first direct chemical and imaging evidence of lithium-induced atomic ordering in amorphous TiO2 nanomaterials and propose new reaction mechanisms that contradict the many works in the published literature on the lithiation behavior of these materials. The lithiation process was conducted in situ inside an atomic resolution transmission electron microscope. Our results indicate that the lithiation started with the valence reduction of Ti4+ to Ti3+ leading to a LixTiO2 intercalation compound. The continued intercalation of Li ions in TiO2 nanotubes triggered an amorphous to crystalline phase transformation. The crystals were formed as nano-islands and identified to be Li2Ti2O4 with cubic structure (a = 8.375 ). The tendency for the formation of these crystals was verified with density functional theory (DFT) simulations. The size of the crystalline islands provides a characteristic length scale (?5 nm) at which the atomic bonding configuration has been changed within a short time period. This phase transformation is associated with local inhomogeneities in Li distribution. On the basis of these observations, a new reaction mechanism is proposed to explain the first cycle lithiation behavior in amorphous TiO2 nanotubes.

  5. Nanoscale compositional analysis of NiTi shape memory alloy films deposited by DC magnetron sputtering

    SciTech Connect (OSTI)

    Sharma, S. K.; Mohan, S.; Bysakh, S.; Kumar, A.; Kamat, S. V.

    2013-11-15

    The formation of surface oxide layer as well as compositional changes along the thickness for NiTi shape memory alloy thin films deposited by direct current magnetron sputtering at substrate temperature of 300 °C in the as-deposited condition as well as in the postannealed (at 600 °C) condition have been thoroughly studied by using secondary ion mass spectroscopy, x-ray photoelectron spectroscopy, and scanning transmission electron microscopy-energy dispersive x-ray spectroscopy techniques. Formation of titanium oxide (predominantly titanium dioxide) layer was observed in both as-deposited and postannealed NiTi films, although the oxide layer was much thinner (8 nm) in as-deposited condition. The depletion of Ti and enrichment of Ni below the oxide layer in postannealed films also resulted in the formation of a graded microstructure consisting of titanium oxide, Ni{sub 3}Ti, and B2 NiTi. A uniform composition of B2 NiTi was obtained in the postannealed film only below a depth of 200–250 nm from the surface. Postannealed film also exhibited formation of a ternary silicide (Ni{sub x}Ti{sub y}Si) at the film–substrate interface, whereas no silicide was seen in the as-deposited film. The formation of silicide also caused a depletion of Ni in the film in a region ∼250–300 nm just above the film substrate interface.

  6. Photo-oxidative degradation of TiO{sub 2}/polypropylene films

    SciTech Connect (OSTI)

    Garca-Montelongo, X.L.; Martnez-de la Cruz, A.; Vzquez-Rodrguez, S.; Torres-Martnez, Leticia M.

    2014-03-01

    Graphical abstract: - Highlights: Photo-oxidative degradation of polypropylene is accelerated by TiO{sub 2} incorporation. Weight loss, FTIR, SEM and GPC shown high degree of degradation of polypropylene. A mechanism of the photo-degradation of polypropylene by TiO{sub 2} is proposed. - Abstract: Photo-oxidative degradation of polypropylene films with TiO{sub 2} nanoparticles incorporated was studied in a chamber of weathering with Xenon lamps as irradiation source. TiO{sub 2} powder with crystalline structure of anatase was synthesized by thermal treatments at 400 and 500 C starting from a precursor material obtained by solgel method. Composites of TiO{sub 2}/polypropylene were prepared with 0.1, 0.5 and 1.0 wt% of TiO{sub 2}. The mixture of components was performed using a twin screw extruder, the resulting material was pelletized by mechanical fragmenting and then hot-pressed in order to form polypropylene films with TiO{sub 2} dispersed homogeneously. Photo-oxidative degradation process was followed by visual inspection, weight loss of films, scanning electron microscopy (SEM), infrared spectroscopy with Fourier transformed (FTIR), and gel permeation chromatography (GPC)

  7. Effect of the top electrode materials on the resistive switching characteristics of TiO{sub 2} thin film

    SciTech Connect (OSTI)

    Oh, Sang Chul; Jung, Ho Yong; Lee, Heon

    2011-06-15

    Various metals, such as Pt, stainless steel (SUS), Al, Ni, and Ti, were used as a top electrode (TE) to evaluate the dependency of the resistive switching characteristics on the TE of the metal/TiO{sub 2}/Pt structure. The variation of the chemical composition of TiO{sub 2} in the metal/TiO{sub 2}/Pt structure before and after switching was examined to identify the factors affecting the resistive switching characteristics of the samples with various TE materials. In the case of TE/TiO{sub 2}/Pt structures showing unstable resistive switching behavior, e.g., those with the Al, Ni, and Ti TEs, secondary ion mass spectrometry revealed an increase in the oxygen concentration at the interface area between the TE metal and TiO{sub 2}. This suggests that the oxidation reaction at the interface between the TE metal and TiO{sub 2} might cause the TE/TiO{sub 2}/Pt structure to exhibit unstable resistive switching characteristics. According to these results, the oxidation reaction at the interface between the metal TE and TiO{sub 2} thin film is a primary factor affecting the resistive switching characteristics of TiO{sub 2}-based Resistive Random Access Memory devices.

  8. Tailoring the crystal structure of TiO{sub 2} thin films from the anatase to rutile phase

    SciTech Connect (OSTI)

    Kotake, Haruka; Jia, Junjun; Nakamura, Shin-ichi; Shigesato, Yuzo; Okajima, Toshihiro

    2015-07-15

    TiO{sub 2} films with various Sn concentrations were deposited on quartz substrates using rf reactive magnetron sputtering. The crystal structure was investigated by using x-ray diffraction, Raman spectroscopy, and transmission electron microscopy, and the chemical states of Ti and Sn were analyzed by x-ray absorption near edge structure (XANES) spectroscopy. Without Sn doping, TiO{sub 2} films change the crystal structure from rutile to anatase as the total gas pressure increases in the sputtering deposition. On the other hand, Sn doping induces the transformation of TiO{sub 2} crystalline structure from anatase to rutile phase, where the XANES spectra implied that Sn substitutes into Ti site of rutile TiO{sub 2}. Atomic force microscope analyses revealed that the Sn-doped TiO{sub 2} films exhibited a flat surface with the roughness of approximately 2 nm.

  9. Efficient photocatalytic degradation of gaseous formaldehyde by the TiO{sub 2}/tourmaline composites

    SciTech Connect (OSTI)

    Zhang, Gaoke Qin, Xi

    2013-10-15

    Graphical abstract: - Highlights: The TiO{sub 2}/tourmaline composites were prepared by a solgel method. The composites exhibited excellent photocatalytic activity and good stability. The physicochemical property of tourmaline may be favor for the degradation of HCHO. The mixed-phase of anatase and rutile TiO{sub 2} may be favor for the degradation of HCHO. - Abstract: The TiO{sub 2} supported tourmaline composites were prepared by a solgel method and used as a photocatalyst for the degradation of formaldehyde (HCHO). The composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), N{sub 2} adsorptiondesorption, Fourier transform infrared (FT-IR) spectroscopy and UVvis diffuse reflectance spectroscopy (UVvis DRS). The results indicate that the mixed-phase of anatase and rutile exists in the TiO{sub 2}/tourmaline composites. The specific surface area of the TiO{sub 2}/tourmaline composites is much higher than that of the pure TiO{sub 2}. The TiO{sub 2}/tourmaline composites exhibited excellent photocatalytic activity for the degradation of HCHO, which was 6 times higher than that of the pure TiO{sub 2}. Moreover, the excellent photocatalytic activity of the composites was fully maintained after five photocatalytic cycles, which may be attributed to the physicochemical property of tourmaline and the mixed-phase of anatase and rutile in the TiO{sub 2}/tourmaline composites.

  10. Electrochromism in sol-gel deposited TiO(sub 2) films

    SciTech Connect (OSTI)

    Bell, J.M.; Barczynska, J.; Evans, L.A.; MacDonald, K.A.; Wang, J.; Green, D.C.; Smith, G.B.

    1994-12-31

    Electrochromism in sol-gel deposited TiO{sub 2} films and films containing TiO{sub 2} and WO{sub 3} has been observed. The films are deposited by dip-coating from a precursor containing titanium isopropoxide in ethanol or titanium propoxide in ethanol, and after deposition the films are heat treated to between 250 C and 300 C. The films do not show any signs of crystallinity. However substantial coloration is observed using Li{sup +} ions in a non-aqueous electrolyte, both in pure TiO{sub 2} films and in mixed metal oxide films (WO{sub 3}:TiO{sub 2}), although the voltage required to produce coloration is different in the two cases. Results will be presented detailing the optical switching and charge transport properties of the films during cyclic voltammetry. These results will be used to compare the performance of the TiO{sub 2} films with other electrochromics. The TiO{sub 2} and mixed metal films all color cathodically, and the colored state is a neutral greyish color for TiO{sub 2}, while the bleached state is transparent and colorless. Results on coloration efficiency and the stability under repeated electrochemical cycling will also be presented. The neutral color of the TiO{sub 2} films and mixed-metal films means that electrochromic windows based on TiO{sub 2} may have significant advantages over WO{sub 3}-based windows. A detailed analysis of the optical properties of the colored state of the films will be presented. The dynamics of coloration for these films is also under investigation, and preliminary results will be presented.

  11. Characterization of oxygen and titanium diffusion at the anatase TiO2(001) surface

    SciTech Connect (OSTI)

    Herman, Gregory S.; Zehr, Robert T.; Henderson, Michael A.

    2013-06-01

    The diffusion of intrinsic defects in a single crystal anatase TiO2(001) film was explored by isotopic labeling and static secondary ion mass spectrometry. Using both 46Ti and 18O as isotopic labels, we show that the anatase surface responds to redox imbalances by diffusion of both Ti and O into the bulk under vacuum reduction and (at least) Ti from the bulk to the surface during oxidation. The diffusion of Ti between the bulk and surface in anatase TiO2(001) closely resembles what was observed in the literature for the rutile TiO2(110) surface, however the latter is not known to have oxygen diffusion between the bulk and surface under typical ultrahigh vacuum conditions. We speculate that the open lattice of the anatase bulk structure may facilitate independent diffusion of both point defects (Ti interstitials and O vacancies) or concerted diffusion of "TiO" subunits. The authors gratefully acknowledge S.A. Chambers of Pacific Northwest National Laboratory (PNNL) for providing the anatase samples. This research was supported by the U.S. Department of Energy (DOE) Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, the Office of Naval Research Contract Number 200CAR262, and the Oregon Nanoscience and Microtechnologies Institute. PNNL is operated for the U.S. DOE by Battelle under Contract Number DE05-AC76RL0 1830. The research was performed in the William R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facility funded by the U.S. DOE Office of Biological and Environmental Research.

  12. Atomic structure of nanometer-sized amorphous TiO2

    SciTech Connect (OSTI)

    Zhang, H.; Chen, B.; Banfield, J.F.; Waychunas, G.A.

    2008-10-15

    Amorphous titania (TiO{sub 2}) is an important precursor for synthesis of single-phase nanocrystalline anatase. We synthesized x-ray amorphous titania by hydrolysis of titanium ethoxide at the ice point. Transmission electron microscopy examination and nitrogen gas adsorption indicated the particle size of the synthesized titania is {approx} 2 nm. Synchrotron wide-angle x-ray scattering (WAXS) was used to probe the atomic correlations in this amorphous sample. Atomic pair-distribution function (PDF) derived from Fourier transform of the WAXS data was used for reverse Monte Carlo (RMC) simulations of the atomic structure of the amorphous TiO{sub 2} nanoparticles. Molecular dynamics simulations were used to generate input structures for the RMC. X-ray absorption spectroscopy (XAS) simulations were used to screen candidate structures obtained from the RMC by comparing with experimental XAS data. The structure model that best describes both the WAXS and XAS data shows that an amorphous TiO{sub 2} particle consists of a highly distorted shell and a small strained anatase-like crystalline core. The average coordination number of Ti is 5.3 and most Ti-O bonds are populated around 1.940 {angstrom}. Relative to bulk TiO{sub 2}, the reduction of the coordination number is primarily due to the truncation of the Ti-O octahedra at the amorphous nanoparticle surface and the shortening of the Ti-O bond length to the bond contraction in the distorted shell. The preexistence of the anatase-like core may be critical to the formation of single-phase nanocrystalline anatase in crystallization of amorphous TiO{sub 2} upon heating.

  13. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-Na₀̣₅Bi₀̣₅TiO₃ piezoelectric materials

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

    2015-02-26

    We synthesized grain-oriented lead-free piezoelectric materials in (K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-xNa₀̣₅Bi₀̣₅TiO₃ (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d₃₃ ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectricmore » materials.« less

  14. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K???Bi???TiO?-BaTiO?-Na???Bi???TiO? piezoelectric materials

    SciTech Connect (OSTI)

    Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

    2015-02-26

    We synthesized grain-oriented lead-free piezoelectric materials in (K???Bi???TiO?-BaTiO?-xNa???Bi???TiO? (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d?? ~ 190pC/N) and high temperature stability (~160C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180 domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials.

  15. Design of highly ordered Ag-SrTiO{sub 3} nanotube arrays for photocatalytic degradation of methyl orange

    SciTech Connect (OSTI)

    Sun Yue; Liu Jiawen; Li Zhonghua

    2011-08-15

    Ag-SrTiO{sub 3} nanotube arrays were successfully prepared for the degradation of methyl orange (MO) under ultraviolet irradiation. In order to form highly ordered SrTiO{sub 3} nanotube arrays, the preparation of TiO{sub 2} nanotube arrays by anodic oxidation of titanium foil in different electrolytes was investigated. The selected organic solvents in electrolytes include glycerol, dimethyl sulfoxide and glycol. The results indicate that the morphology of TiO{sub 2} nanotube arrays prepared in glycol containing ammonium fluoride electrolyte is more regular. Then SrTiO{sub 3} nanotube arrays were synthesized by a hydrothermal method using TiO{sub 2} nanotube arrays as the precursor. In order to further improve the photocatalytic activity of SrTiO{sub 3} nanotube arrays, Ag nanoparticles were loaded on SrTiO{sub 3} nanotube arrays by two sets of experiments. The loaded Ag results in an enhancement of photocatalytic activity of SrTiO{sub 3} nanotube arrays. Moreover, the effect of pH on the photocatalytic degradation of MO was also studied. - Graphical abstract: Ag-SrTiO{sub 3} nanotube arrays were successfully prepared. The photocatalytic activity was evaluated by degradation of methyl orange under ultraviolet irradiation. Highlights: > TiO{sub 2} nanotube arrays prepared in glycol+NH{sub 4}F electrolyte are more regular. > Highly ordered Ag-SrTiO{sub 3} nanotube arrays were successfully synthesized. > Ag loading could enhance the photocatalytic activity of SrTiO{sub 3} nanotube arrays. > Ag-SrTiO{sub 3} nanotube arrays show excellent catalytic activity at a low pH value.

  16. On the origins of hardness of Cu–TiN nanolayered composites

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Pathak, S.; Li, N.; Maeder, X.; Hoagland, R. G.; Baldwin, J. K.; Michler, J.; Misra, A.; Wang, J.; Mara, N. A.

    2015-07-18

    We investigated the mechanical response of physical vapor deposited Cu–TiN nanolayered composites of varying layer thicknesses from 5 nm to 200 nm. Both the Cu and TiN layers were found to consist of single phase nanometer sized grains. The grain sizes in the Cu and TiN layers, measured using transmission electron microscopy and X-ray diffraction, were found to be comparable to or smaller than their respective layer thicknesses. Indentation hardness testing revealed that the hardness of such nanolayered composites exhibits a weak dependence on the layer thickness but is more correlated to their grain size.

  17. Doping of TiO 2 Polymorphs for Altered Optical and Photocatalytic Properties

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Nie, Xiliang; Zhuo, Shuping; Maeng, Gloria; Sohlberg, Karl

    2009-01-01

    Tmore » his paper reviews recent investigations of the influence of dopants on the optical properties of TiO 2 polymorphs.he common undoped polymorphs of TiO 2 are discussed and compared.he results of recent doping efforts are tabulated, and discussed in the context of doping by elements of the same chemical group. Dopant effects on the band gap and photocatalytic activity are interpreted with reference to a simple qualitative picture of the TiO 2 electronic structure, which is supported with first-principles calculations.« less

  18. Structural characterization and electronic structure of laser treated TiN thin film

    SciTech Connect (OSTI)

    Soni, Sheetal; Nair, K. G. M.; Phase, D. M.; Gupta, Ratnesh

    2012-06-05

    TiN thin films prepared by laser treatment using Kr-F excimer laser in the controlled atmosphere. The depth distribution and composition of nitrogen and contaminated oxygen have been determined by non-Rutherford proton backscattering using 1.7 MeV Tendetron accelerator. The electronic structure of TiN thin film have been characterized by resonant photoelectron spectroscopy using indus-I synchrotron radiation. Specifically, complex resonance profile that shows the enhancement at 45 eV which is consistent with the resonant photoemission of Ti 3d states involved in the Titanium nitride and oxide.

  19. Photo-induced wettability of TiO{sub 2} film with Au buffer layer

    SciTech Connect (OSTI)

    Purkayastha, Debarun Dhar; Sangani, L. D. Varma; Krishna, M. Ghanashyam; Madhurima, V.

    2014-04-24

    The effect of thickness of Au buffer layer (15-25 nm) between TiO{sub 2} film and substrate on the wettability of TiO{sub 2} films is reported. TiO{sub 2} films grown on Au buffer layer have a higher contact angle of 96-;100 as compared to 47.6o for the film grown without buffer layer. The transition from hydrophobicity to hydrophilicity under UV irradiation occurs within 10 min. for the buffer layered films whereas it is almost 30 min. for the film grown without buffer layer. The enhanced photo induced hydrophilicity is shown to be surface energy driven.

  20. Transmutation-induced embrittlement of V-Ti-Ni and V-Ni alloys in HFIR

    SciTech Connect (OSTI)

    Ohnuki, S.; Takahashi, H.; Garner, F.A.; Pawel, J.E.

    1996-04-01

    Vanadium, V-1Ni, V-10Ti and V-10Ti-1Ni (at %) were irradiated in HFIR to doses ranging from 18 to 30 dpa and temperatures between 300 and 600C. Since the irradiation was conducted in a highly thermalized neutron spectrum without shielding against thermal neutrons, significant levels of chromium (15-22%) were formed by transmutation. The addition of such large chromium levels strongly elevated the ductile to brittle transition temperature. At higher irradiation temperatures radiation-induced segregation of transmutant Cr and solute Ti at specimen surfaces leads to strong increases in the density of the alloy.

  1. Doping ofTiO2Polymorphs for Altered Optical and Photocatalytic Properties

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Nie, Xiliang; Zhuo, Shuping; Maeng, Gloria; Sohlberg, Karl

    2009-01-01

    This paper reviews recent investigations of the influence of dopants on the optical properties ofTiO2polymorphs. The common undoped polymorphs ofTiO2are discussed and compared. The results of recent doping efforts are tabulated, and discussed in the context of doping by elements of the same chemical group. Dopant effects on the band gap and photocatalytic activity are interpreted with reference to a simple qualitative picture of theTiO2electronic structure, which is supported with first-principles calculations.

  2. Electron microscopy of Mg/TiO{sub 2} photocatalyst morphology for deep desulfurization of diesel

    SciTech Connect (OSTI)

    Yin, Yee Cia; Kait, Chong Fai Fatimah, Hayyiratul Wilfred, Cecilia

    2015-07-22

    A series of Mg/TiO{sub 2} photocatalysts were prepared and characterized using Field Emission Scanning Electron Microscopy (FESEM) and High-Resolution Transmission Electron Microscopy (HRTEM). The average particle sizes of the photocatalysts were ranging from 25.7 to 35.8 nm. Incorporation of Mg on TiO{sub 2} did not lead to any surface lattice distortion to TiO{sub 2}. HRTEM data indicated the presence of MgO and Mg(OH){sub 2} mixture at low Mg loading while at higher Mg loading, the presence of lamellar Mg-oxyhydroxide intermediates and Mg(OH){sub 2}.

  3. Structural evolution in Ti-Cu-Ni metallic glasses during heating

    SciTech Connect (OSTI)

    Gargarella, P.; Pauly, S.; Stoica, M.; Khn, U.; Vaughan, G.; Afonso, C. R. M.; Eckert, J.

    2015-01-01

    The structural evolution of Ti{sub 50}Cu{sub 43}Ni{sub 7} and Ti{sub 55}Cu{sub 35}Ni{sub 10} metallic glasses during heating was investigated by in-situ synchrotron X-ray diffraction. The width of the most intense diffraction maximum of the glassy phase decreases slightly during relaxation below the glass transition temperature. Significant structural changes only occur above the glass transition manifesting in a change in the respective peak positions. At even higher temperatures, nanocrystals of the shape memory B2-Ti(Cu,Ni) phase precipitate, and their small size hampers the occurrence of a martensitic transformation.

  4. Effects of aging on the characteristics of TiNiPd shape memory alloy thin films

    SciTech Connect (OSTI)

    Zhang Congchun

    2008-07-15

    TiNiPd thin films have been deposited on glass substrate using R.F. magnetron sputtering. Effects of annealing and aging on the microstructure, phase transformation behaviors and shape memory effects of these thin films have been studied by X-ray diffractometry, differential scanning calorimeter, tensile tests and internal friction characteristics. The TiNiPd thin films annealed at 750 deg. C exhibit uniform martensite/austenite transformations and shape memory effect. Aging at 450 deg. C for 1 h improved the uniformity of transformations and shape memory effect. Long time aging decreased transformation temperatures and increased the brittleness of TiNiPd thin films.

  5. Catalytic Effect of Ti for Hydrogen Cycling in NaAlH4 | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Catalytic Effect of Ti for Hydrogen Cycling in NaAlH4 Catalytic Effect of Ti for Hydrogen Cycling in NaAlH4 A presentation about how hydrogen can be reversibly absorbed and desorbed from NaAlH4 under moderate conditions by the addition of catalysts. catalytic_effect_of_ti.pdf (877.97 KB) More Documents & Publications Final Report for the DOE Metal Hydride Center of Excellence Effects of Point Defects and Impurities on Kinetics in NaAlH4 Prediction of New Hydrogen Storage Compounds

  6. Model NbTi Helical Solenoid Fabrication and Test Results

    SciTech Connect (OSTI)

    Andreev, N.; Barzi, E.; Chlachidze, G.; Evbota, D.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Makarov, A.; Novitski, I.; Orris, D.F.; Tartaglia, M.A.; /Fermilab

    2011-09-01

    A program to develop model magnets for a helical cooling channel is under way at Fermilab. In the first steps of a planned sequence of magnets, two four-coil helical solenoid models with 300 mm aperture have been fabricated and tested. These two models, HSM01 and HSM02, used insulated NbTi Rutherford cable wound onto stainless steel rings with spliceless transitions between coils. Strip heaters were included for quench protection of each coil, and the coils were epoxy-impregnated after winding inside the support structures. Based on the results of the first model the second model was made using a cable with optimized cross-section, improved winding and epoxy-impregnation procedures, enhanced ground insulation, and included heat exchange tubing for a test of conduction cooling. We report on the results and lessons learned from fabrication and tests of these two models.

  7. Chemical vapor infiltration of TiB{sub 2} composites

    SciTech Connect (OSTI)

    Besmann, T.M.

    1995-05-01

    This program is designed to develop a Hall-Heroult aluminum smelting cathode with substantially improved properties. The carbon cathodes in current use require significant anode-to-cathode spacing in order to prevent shorting, causing significant electrical inefficiencies. This is due to the non-wettability of carbon by aluminum which causes instability in the cathodic aluminum pad. It is suggested that a fiber reinforced-TiB{sub 2} matrix composite would have the requisite wettability, strength, strain-to-failure, cost, and lifetime to solve this problem. The approach selected to fabricate such a cathode material is chemical vapor infiltration (CVI). This program is designed to evaluate potential fiber reinforcements, fabricate test specimens, and test the materials in a static bath and lab-scale Hall cell.

  8. Average and local structure of the Pb-free ferroelectric perovskites (Sr,Sn)TiO3 and (Ba,Ca,Sn)TiO3

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Laurita, Geneva; Page, Katharine; Suzuki, Shoichiro; Seshadri, Ram

    2015-12-16

    The characteristic structural off -centering of Pb2+ in oxides, associated with its 6s2 lone pair, allows it to play a dominant role in polar materials, and makes it a somewhat ubiquitous component of ferroelectrics. In this work, we examine the compounds Sr0.9Sn0.1TiO3 and Ba0.79Ca0.16Sn0.05TiO3 using neutron total scattering techniques with data acquired at di erent temperatures. In these compounds, previously reported as ferroelectrics, Sn2+ appears to display some of the characteristics of Pb2+. We compare the local and long-range structures of the Sn2+-substituted compositions to the unsubstituted parent compounds SrTiO3 and BaTiO3. Lastly, we find that even at these smallmore » substitution levels, the Sn2+ lone pairs drive the local ordering behavior, with the local structure of both compounds more similar to the structure of PbTiO3 rather than the parent compounds.« less

  9. DE-PS26-08NT00537

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    TBD Notice Type: Sources Sought Synopsis: The U.S. Department of Energy (DOE), National Energy TechnologyLaboratory (NETL), is conducting a Market Survey to identify capable 8(a) certified business entities with Model Integration (CMMI) for Development (CMMI-DEV) level 2 or higher interested in providing on-site Information Technology (IT) Support for NETL. For the purpose of this source sought market research, NETL will not consider a Joint Venture (JV) entity (or other teaming arrangements)

  10. DE-NT0006556 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The depth of the reservoir decreases and the viscosity increases toward the west. Currently, the operators are planning to test cold heavy oil production with sand (CHOPS) in Ugnu, ...

  11. DE-NT0005682 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Unconventional oil resources in the United States include two trillion barrels in oil shales, 16 billion barrels in oil sands, and 73 billion barrels remaining heavy oil-in-place. ...

  12. fc26-06nt42391 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the power plant would be transported via pipeline for beneficial use in existing enhanced ... The project addresses advances in coal gasification systems and technologies that permit ...

  13. Cooperative Agreement DE-FC26-06NT42804

    Office of Scientific and Technical Information (OSTI)

    ... Capturing CO 2 from these high concentration streams is easier and cheaper than capturing from low concentration streams like post combustion flue gas from a coal power plant. ...

  14. DE-NT0005665 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... the University of Alaska and the U.S. Geological Survey, as well as other U.S. and ... Water samples were collected from locations without grounded ice for methane oxidation ...

  15. DE-NT0005668 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... us that this is an attribute of the data due to geology. The EW line that crosses through the SE crater is overlain on chirp acoustic line 119 from Sleeper et al. (2006) in ...

  16. DE-NT0006553 | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... 288,378 Field Test Planning (Phase 2) - DOE Contribution: 0, Cost Share Contribution: 2,150,656 Well Drilling and Completion (Phase 3A) - DOE Contribution: 8,220,765, Cost ...

  17. Cooperative Agreement DE-FC26-06NT42804

    Office of Scientific and Technical Information (OSTI)

    ... Business in China-U.S. and China: Partners in Development of Green Coal by Fred Palmer, Vice President Peabody Energy ENN Alternative Energy Program-New Pathway to a Low ...

  18. Growth control of oxygen stoichiometry in homoepitaxial SrTiO3...

    Office of Scientific and Technical Information (OSTI)

    Growth control of oxygen stoichiometry in homoepitaxial SrTiO3 films by pulsed laser epitaxy in high vacuum Prev Next Title: Growth control of oxygen stoichiometry in ...

  19. Amphoteric doping of praseodymium Pr3+ in SrTiO3 grain boundaries

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yang, H.; Lee, H. S.; Kotula, P. G.; Sato, Y.; Ikuhara, Y.; Browning, N. D.

    2015-03-26

    Charge Compensation in rare-earth Praseodymium (Pr3+) doped SrTiO3 plays an important role in determining the overall photoluminescence properties of the system. Here, the Pr3+ doping behavior in SrTiO3 grain boundaries (GBs) is analyzed using aberration corrected scanning transmission electron microscopy (STEM). The presence of Pr3+ induces structure variations and changes the statistical prevalence of GB structures. In contrast to the assumption that Pr3+ substitutes for A site as expected in the bulk, Pr3+ is found to substitute both Sr and Ti sites inside GBs with the highest concentration in the Ti sites. As a result, this amphoteric doping behavior inmore »the boundary plane is further confirmed by first principles theoretical calculations.« less

  20. An experimental study of the (Ti-6Al-4V)-xH phase diagram using...

    Office of Scientific and Technical Information (OSTI)

    An experimental study of the (Ti-6Al-4V)-xH phase diagram using in situ synchrotron XRD and TGADSC techniques This content will become publicly available on February 10, 2017 ...

  1. Molecular Hydrogen Formation from Proximal Glycol Pairs on TiO2(110)

    SciTech Connect (OSTI)

    Chen, Long; Li, Zhenjun; Smith, R. Scott; Kay, Bruce D.; Dohnalek, Zdenek

    2014-04-16

    Understanding hydrogen formation on TiO2 surfaces is of great importance as it could provide fundamental insight into water splitting for hydrogen production using solar energy. In this work, hydrogen formation from glycols having different numbers of methyl end-groups have been studied using temperature pro-grammed desorption on reduced, hydroxylated, and oxidized TiO2(110) surfaces. The results from OD-labeled glycols demon-strate that gas-phase molecular hydrogen originates exclusively from glycol hydroxyl groups. The yield is controlled by a combi-nation of glycol coverage, steric hindrance, TiO2(110) order and the amount of subsurface charge. Combined, these results show that proximal pairs of hydroxyl aligned glycol molecules and subsurface charge are required to maximize the yield of this redox reaction. These findings highlight the importance of geometric and electronic effects in hydrogen formation from adsorbates on TiO2(110).

  2. Studies on the effect of acid treated TiO{sub 2} on the electrical...

    Office of Scientific and Technical Information (OSTI)

    Studies on the effect of acid treated TiOsub 2 on the electrical and tensile properties of hexanoyl chitosan-polystyrene-LiCFsub 3SOsub 3 composite polymer electrolytes ...

  3. Amphoteric doping of praseodymium Pr3+ in SrTiO3 grain boundaries

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yang, H.; Lee, H. S.; Kotula, P. G.; Sato, Y.; Ikuhara, Y.; Browning, N. D.

    2015-03-26

    Charge Compensation in rare-earth Praseodymium (Pr3+) doped SrTiO3 plays an important role in determining the overall photoluminescence properties of the system. Here, the Pr3+ doping behavior in SrTiO3 grain boundaries (GBs) is analyzed using aberration corrected scanning transmission electron microscopy (STEM). The presence of Pr3+ induces structure variations and changes the statistical prevalence of GB structures. In contrast to the assumption that Pr3+ substitutes for A site as expected in the bulk, Pr3+ is found to substitute both Sr and Ti sites inside GBs with the highest concentration in the Ti sites. As a result, this amphoteric doping behavior inmore » the boundary plane is further confirmed by first principles theoretical calculations.« less

  4. Process for producing Ti-Cr-Al-O thin film resistors

    DOE Patents [OSTI]

    Jankowski, Alan F.; Schmid, Anthony P.

    2001-01-01

    Thin films of Ti-Cr-Al-O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti-Cr-Al-O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti-Cr-Al-O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti-Cr-Al-O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  5. Flat panel display using Ti-Cr-Al-O thin film

    DOE Patents [OSTI]

    Jankowski, Alan F.; Schmid, Anthony P.

    2002-01-01

    Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  6. Mechanical properties of bulk and nanoscale TiO[subscript 2] phases

    SciTech Connect (OSTI)

    Swamy, V.; Holbig, E.; Dubrovinksy, L.S.; Prakapenka, V.; Muddle, B.C.

    2008-09-11

    The mechanical properties of bulk and nanoscale TiO{sub 2} phases are examined with a view to assess the available bulk modulus and hardness data, and to understand the size-dependent behaviors. The bulk modulus values of thermodynamically stable bulk TiO{sub 2} phases show a general correlation with Ti-O coordination number. As with the cotunnite-structured (OII) phase, it is likely that the seven-coordinated OI and eight-coordinated fluorite forms of TiO{sub 2} are ultrahard substances. Of the nanoscale phases investigated thus far, nanocrystalline anatase displays the strongest size dependence of bulk modulus values, with possible stiffening behavior effected by incipient grain boundary amorphization under pressure. Nanocrystalline rutile and baddeleyite phases do not show appreciable size dependence in their compression behaviors.

  7. Preparation of atomically flat rutile TiO2(001) surfaces for...

    Office of Scientific and Technical Information (OSTI)

    surfaces for oxide film growth This content will become publicly available on January 1, 2017 Prev Next Title: Preparation of atomically flat rutile TiO2(001) surfaces ...

  8. Recyclability study on Inconel 718 and Ti-6Al-4V powders for...

    Office of Scientific and Technical Information (OSTI)

    Ti-6Al-4V, on the other hand, finds its reuse time governed by the oxygen pick up that occurs during and in between build cycles. The detailed results have been presented. Authors: ...

  9. Infrared optical absorption in low-spin Fe 2+ -doped SrTiO 3...

    Office of Scientific and Technical Information (OSTI)

    This content will become publicly available on January 6, 2017 Title: Infrared optical absorption in low-spin Fe 2+ -doped SrTiO 3 Authors: Comes, Ryan B. ; Kaspar, Tiffany C. ; ...

  10. Irradiation creep of the US Heat 832665 of V-4Cr-4Ti (Journal...

    Office of Scientific and Technical Information (OSTI)

    The paper presents irradiation creep data for V-4Cr-4Ti irradiated to 3.7 dpa at 425 and 600 C in the HFIR-17J experiment. Creep deformation was characterized by measuring ...

  11. Adhesion strength of sputtered TiAlN-coated WC insert tool

    SciTech Connect (OSTI)

    Budi, Esmar; Razali, M. Mohd.; Nizam, A. R. Md.

    2013-09-09

    The adhesion strength of TiAlN coating that deposited by using DC magnetron sputtering on WC insert tool are studied. TiAlN coating are deposited on Tungsten Carbide (WC) insert tool by varying negatively substrate bias from 79 to 221 volt and nitrogen flow rate from 30 to 72 sccm. The adhesion strength are obtained by using Rockwell indentation test method with a Brale diamond at applied load of 60,100 and 150 kgf. The lateral diameter of indentation is plotted on three different applied loads and the adhesion strength of TiAlN coating was obtained from the curved slopes at 100 and 150 kgf. The lower curve slop indicated better adhesion strength. The results shows that the adhesion strength of sputterred TiAlN coating tend to increase as the negatively substrate bias and nitrogen flow rate are increased.

  12. A New Method of Low Cost Production of Ti Alloys to Reduce Energy...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    by sintering of TiH 2 in (a) hydrogen, (b) vacuum (SEM ) Refine grain sizes by controlling H 2 content and phase transformation in as-sintered state High density - >99% ...

  13. Infrared Optical Absorption in Low-spin Fe2+-doped SrTiO3 (Journal...

    Office of Scientific and Technical Information (OSTI)

    Title: Infrared Optical Absorption in Low-spin Fe2+-doped SrTiO3 Band gap engineering in ... The novel electronic states observed here offer a new avenue for band gap engineering in ...

  14. FIRST-PRINCIPLES PHASE STABILITY IN THE TI-V ALLOY SYSTEM (Journal...

    Office of Scientific and Technical Information (OSTI)

    IN THE TI-V ALLOY SYSTEM Citation Details In-Document ... OSTI Identifier: 1108866 Report Number(s): LLNL-JRNL-635374 DOE Contract Number: W-7405-ENG-48 Resource Type: Journal ...

  15. Splitting of magnetic dipole modes in anisotropic TiO 2 micro-spheres: Splitting of magnetic dipole modes in anisotropic TiO 2 micro-spheres

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khromova, Irina; Kužel, Petr; Brener, Igal; Reno, John L.; Chung Seu, U-Chan; Elissalde, Catherine; Maglione, Mario; Mounaix, Patrick; Mitrofanov, Oleg

    2016-06-27

    Monocrystalline titanium dioxide (TiO2) micro-spheres support two orthogonal magnetic dipole modes at terahertz (THz) frequencies due to strong dielectric anisotropy. For the first time, we experimentally detected the splitting of the first Mie mode in spheres of radii inline imagem through near-field time-domain THz spectroscopy. By fitting the Fano lineshape model to the experimentally obtained spectra of the electric field detected by the sub-wavelength aperture probe, we found that the magnetic dipole resonances in TiO2 spheres have narrow linewidths of only tens of gigahertz. Lastly, anisotropic TiO2 micro-resonators can be used to enhance the interplay of magnetic and electric dipolemore » resonances in the emerging THz all-dielectric metamaterial technology.« less

  16. Theoretical Assessment on the Phase Transformation Kinetic Pathways of Multi-component Ti Alloys: Application to Ti-6Al-4V

    SciTech Connect (OSTI)

    Ji, Yanzhou; Heo, Tae Wook; Zhang, Fan; Chen, Long-Qing

    2015-12-21

    Here we present our theoretical assessment of the kinetic pathways during phase transformations of multi-component Ti alloys. Employing the graphical thermodynamic approach and an integrated free energy function based on the realistic thermodynamic database and assuming that a displacive structural transformation occurs much faster than long-range diffusional processes, we analyze the phase stabilities of Ti-6Al-4V (Ti-6wt.%Al-4wt.%V). Our systematic analyses predict a variety of possible kinetic pathways for β to (α + β) transformations leading to different types of microstructures under various heat treatment conditions. In addition, the possibility of unconventional kinetic pathways is discussed. Lastly, we also briefly discuss the application of our approach to general multicomponent/multiphase alloy systems.

  17. Hydrogenated TiO{sub 2} film for enhancing photovoltaic properties of solar cells and self-sensitized effect

    SciTech Connect (OSTI)

    He, Hongcai; Yang, Kui; Wang, Ning Luo, Feifei; Chen, Haijun

    2013-12-07

    Hydrogenated TiO{sub 2} film was obtained by annealing TiO{sub 2} film at 350 °C for 2 h with hydrogen, and TiO{sub 2} films were prepared by screen printing on fluorine-doped tin oxide glass. Structural characterization by X-ray diffraction and electron microscopy did not show obvious difference between hydrogenated TiO{sub 2} film and pristine TiO{sub 2} film. Through optical and electrochemical characterization, the hydrogenated TiO{sub 2} film showed enhanced absorption and narrowed band gap, as well as reduced TiO{sub 2} surface impedance and dark current. As a result, an obviously enhanced photovoltaic effect was observed in the solar cell with hydrogenated TiO{sub 2} as photoanode without adding any dye due to the self-sensitized effect of hydrogenated TiO{sub 2} film, which excited electrons injecting internal conduction band of TiO{sub 2} to generate more photocurrent.

  18. Waterless TiO{sub 2} atomic layer deposition using titanium tetrachloride and titanium tetraisopropoxide

    SciTech Connect (OSTI)

    Anderson, Virginia R.; Cavanagh, Andrew S.; Abdulagatov, Aziz I.; Gibbs, Zachary M.; George, Steven M.

    2014-01-15

    The surface chemistry for TiO{sub 2} atomic layer deposition (ALD) typically utilizes water or other oxidants that can oxidize underlying substrates such as magnetic disks or semiconductors. To avoid this oxidation, waterless or oxidant-free surface chemistry can be used that involves titanium halides and titanium alkoxides. In this study, waterless TiO{sub 2} ALD was accomplished using titanium tetrachloride (TiCl{sub 4}) and titanium tetraisopropoxide (TTIP). In situ transmission Fourier transform infrared (FTIR) studies were employed to study the surface species and the reactions during waterless TiO{sub 2} ALD. At low temperatures between 125 and 225  °C, the FTIR absorbance spectra revealed that the isopropoxide species remained on the surface after TTIP exposures. The TiCl{sub 4} exposures then removed the isopropoxide species and deposited additional titanium species. At high temperatures between 250 and 300  °C, the isopropoxide species were converted to hydroxyl species by β-hydride elimination. The observation of propene gaseous reaction product by quadrupole mass spectrometry (QMS) confirmed the β-hydride elimination reaction pathway. The TiCl{sub 4} exposures then easily reacted with the hydroxyl species. QMS studies also observed the 2-chloropropane and HCl gaseous reaction products and monitored the self-limiting nature of the TTIP reaction. Additional studies examined the waterless TiO{sub 2} ALD growth at low and high temperature. Quartz crystal microbalance measurements observed growth rates of ∼3 ng/cm{sup 2} at a low temperature of 150  °C. Much higher growth rates of ∼15 ng/cm{sup 2} were measured at a higher temperature of 250  °C under similar reaction conditions. X-ray reflectivity analysis measured a growth rate of 0.55 ± 0.05 Å/cycle at 250  °C. X-ray photoelectron depth-profile studies showed that the TiO{sub 2} films contained low Cl concentrations <1 at. %. This waterless TiO{sub 2} ALD process

  19. TiN coated aluminum electrodes for DC high voltage electron guns

    SciTech Connect (OSTI)

    Mamun, Md Abdullah A.; Elmustafa, Abdelmageed A.; Taus, Rhys; Forman, Eric; Poelker, Matthew

    2015-05-15

    Preparing electrodes made of metals like stainless steel, for use inside DC high voltage electron guns, is a labor-intensive and time-consuming process. In this paper, the authors report the exceptional high voltage performance of aluminum electrodes coated with hard titanium nitride (TiN). The aluminum electrodes were comparatively easy to manufacture and required only hours of mechanical polishing using silicon carbide paper, prior to coating with TiN by a commercial vendor. The high voltage performance of three TiN-coated aluminum electrodes, before and after gas conditioning with helium, was compared to that of bare aluminum electrodes, and electrodes manufactured from titanium alloy (Ti-6Al-4V). Following gas conditioning, each TiN-coated aluminum electrode reached −225 kV bias voltage while generating less than 100 pA of field emission (<10 pA) using a 40 mm cathode/anode gap, corresponding to field strength of 13.7 MV/m. Smaller gaps were studied to evaluate electrode performance at higher field strength with the best performing TiN-coated aluminum electrode reaching ∼22.5 MV/m with field emission less than 100 pA. These results were comparable to those obtained from our best-performing electrodes manufactured from stainless steel, titanium alloy and niobium, as reported in references cited below. The TiN coating provided a very smooth surface and with mechanical properties of the coating (hardness and modulus) superior to those of stainless steel, titanium-alloy, and niobium electrodes. These features likely contributed to the improved high voltage performance of the TiN-coated aluminum electrodes.

  20. Observation of Ti{sup 4+} ions in a high power impulse magnetron sputtering plasma

    SciTech Connect (OSTI)

    Andersson, Joakim; Anders, Andre; Ehiasarian, Arutiun P.

    2008-08-18

    Multiply charged titanium ions including Ti{sup 4+} were observed in high power impulse magnetron sputtering discharges. Mass/charge spectrometry was used to identify metal ion species. Quadruply charged titanium ions were identified by isotope-induced broadening at mass/charge 12. Due to their high potential energy, Ti{sup 4+} ions give a high yield of secondary electrons, which in turn are likely to be responsible for the generation of multiply charged states.

  1. TiN coated aluminum electrodes for DC high voltage electron guns

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mamun, Md Abdullah A.; Elmustafa, Abdelmageed A.; Taus, Rhys; Forman, Eric; Poelker, Matthew

    2015-05-01

    Preparing electrodes made of metals like stainless steel, for use inside DC high voltage electron guns, is a labor-intensive and time-consuming process. In this paper, the authors report the exceptional high voltage performance of aluminum electrodes coated with hard titanium nitride (TiN). The aluminum electrodes were comparatively easy to manufacture and required only hours of mechanical polishing using silicon carbide paper, prior to coating with TiN by a commercial vendor. The high voltage performance of three TiN-coated aluminum electrodes, before and after gas conditioning with helium, was compared to that of bare aluminum electrodes, and electrodes manufactured from titanium alloymore » (Ti-6AI-4V). Following gas conditioning, each TiN-coated aluminum electrode reached -225 kV bias voltage while generating less than 100 pA of field emission (<10 pA) using a 40 mm cathode/anode gap, corresponding to field strength of 13.7 MV/m. Smaller gaps were studied to evaluate electrode performance at higher field strength with the best performing TiN-coated aluminum electrode reaching ~22.5 MV/m with field emission less than 100 pA. These results were comparable to those obtained from our best-performing electrodes manufactured from stainless steel, titanium alloy and niobium, as reported in references cited below. The TiN coating provided a very smooth surface and with mechanical properties of the coating (hardness and modulus) superior to those of stainless steel, titanium-alloy, and niobium electrodes. These features likely contributed to the improved high voltage performance of the TiN-coated aluminum electrodes.« less

  2. Enhancing solar photocatalytic detoxification by adsorption of porphyrins onto TiO sub 2

    SciTech Connect (OSTI)

    Majumder, S.A.; Ondrias, M.R. . Dept. of Chemistry); Prairie, M.R.; Shelnutt, J.A. )

    1991-01-01

    Titanium dioxide (TiO{sub 2}) is a known photocatalyst for solar detoxification of water containing organic contaminants including PCB's and dioxins. Unfortunately, the UV light used by the photocatalyst only comprises about 4% of the strong spectrum. Metalloporphyrins strongly absorb in the visible and near infrared region. Using visible light, we have investigated Ni(II) uroporphyrin (NiUroP), Sn(IV)Cl{sub 2} uroporphyrin (SnUroP) and Sn(IV)Cl{sub 2} tetrakis(p-carboxyphenyl) porphyrin (SnTCPP) as possible enhancers of destruction of a model organic compound, salicylic acid (SA), by means of photosensitization of colloidal TiO{sub 2} particles. All three porphyrins are found to adsorb reversibly onto the colloidal TiO{sub 2} upon variation of pH. Adsorption of porphyrins results in the increased colloidal stability of fine TiO{sub 2} particles in the pH range 5--8. While NiUroP on TiO{sub 2} does not show any enhancement of photodestruction, the adsorption of SnUroP increases the destruction rate compared to that of the bare TiO{sub 2} surface. The effect of ambient oxygen on the observed photolability of the Sn porphyrins and enhancement of photodestruction of SA was also investigated. SnTCPP does not photodecompose upon illumination either in the presence or absence of TiO{sub 2}, but neither does it bind to the photocatalyst at pH 6. At pH 4.5 it adsorbs onto TiO{sub 2} but it also photodecompose at this pH. We are attempting to stabilize the adsorbed porphyrins by adding suitable peripheral substituents onto the porphyrin macrocycle. 27 refs., 6 figs.

  3. Preparation and properties of sliver and nitrogen co-doped TiO{sub 2} photocatalyst

    SciTech Connect (OSTI)

    Zhang, Ying; Zhang, Jin; Zhu, Zhongqi; Yan, Ningning; Liu, Qingju

    2013-11-15

    Graphical abstract: - Highlights: The silver and nitrogen co-doped TiO{sub 2} photocatalysts were prepared and characterized. The light absorption threshold wavelength of AgNTiO{sub 2} is red-shifted to visible light. The recombination of the photo-generated electrons and holes of AgNTiO{sub 2} is inhibited. The photocatalytic activity of AgNTiO{sub 2} is remarkable improved. - Abstract: TiO{sub 2} photocatalysts co-doped with different content of Ag and N were prepared by solgel method combined with microwave chemical method. The samples were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), ultravioletvisible diffuse reflectance spectrum (UVvis) and photo-luminescence emission spectrum (PL). The photocatalytic activity was investigated by photocatalytic degradation of methylene blue (MB) under irradiation of fluorescent lamp. The results indicate that Ag and N co-doping can restrain the increase of grain size, broaden the absorption spectrum to visible light region, and inhibit the recombination of the photo-generated electronhole pairs. Moreover, the photocatalytic activity of AgNTiO{sub 2} in MB degradation is remarkable improved. The degradation rate of the sample with Ag:TiO{sub 2} = 0.05 at%, N:TiO{sub 2} = 18.50 wt% in 5 h is 93.44%, which is much higher than that of Degussa P25 (39.40%)

  4. Direct Epoxidation of Propylene over Stabilized Cu+ Surface Sites on Ti Modified Cu2O

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yang, X.; Kattel, S.; Xiong, K.; Mudiyanselage, K.; Rykov, S.; Senanayake, S. D.; Rodriguez, J. A.; Liu, P.; Stacchiola, D. J.; Chen, J. G.

    2015-07-17

    Direct propylene epoxidation by O2 is a challenging reaction because of the strong tendency for complete combustion. Results from the current study demonstrate the feasibility to tune the epoxidation selectivity by generating highly dispersed and stabilized Cu+ active sites in a TiCuOx mixed oxide. The TiCuOx surface anchors the key surface intermediate, oxametallacycle, leading to higher selectivity for epoxidation of propylene.

  5. TiN coated aluminum electrodes for DC high voltage electron guns

    SciTech Connect (OSTI)

    Mamun, Md Abdullah A.; Elmustafa, Abdelmageed A.; Taus, Rhys; Forman, Eric; Poelker, Matthew

    2015-05-01

    Preparing electrodes made of metals like stainless steel, for use inside DC high voltage electron guns, is a labor-intensive and time-consuming process. In this paper, the authors report the exceptional high voltage performance of aluminum electrodes coated with hard titanium nitride (TiN). The aluminum electrodes were comparatively easy to manufacture and required only hours of mechanical polishing using silicon carbide paper, prior to coating with TiN by a commercial vendor. The high voltage performance of three TiN-coated aluminum electrodes, before and after gas conditioning with helium, was compared to that of bare aluminum electrodes, and electrodes manufactured from titanium alloy (Ti-6AI-4V). Following gas conditioning, each TiN-coated aluminum electrode reached -225 kV bias voltage while generating less than 100 pA of field emission (<10 pA) using a 40 mm cathode/anode gap, corresponding to field strength of 13.7 MV/m. Smaller gaps were studied to evaluate electrode performance at higher field strength with the best performing TiN-coated aluminum electrode reaching ~22.5 MV/m with field emission less than 100 pA. These results were comparable to those obtained from our best-performing electrodes manufactured from stainless steel, titanium alloy and niobium, as reported in references cited below. The TiN coating provided a very smooth surface and with mechanical properties of the coating (hardness and modulus) superior to those of stainless steel, titanium-alloy, and niobium electrodes. These features likely contributed to the improved high voltage performance of the TiN-coated aluminum electrodes.

  6. Structural, morphological and interfacial characterization of Al-Mg/TiC composites

    SciTech Connect (OSTI)

    Contreras, A. . E-mail: acontrer@imp.mx; Angeles-Chavez, C.; Flores, O.; Perez, R.

    2007-08-15

    Morphological and structural characterization of Al-Mg/TiC composites obtained by infiltration process and wetting by the sessile drop technique were studied. Focusing at the interface, wetting of TiC substrates by molten Al-Mg-alloys at 900 deg. C was investigated. Electron probe microanalysis (EPMA) indicated that aluminum carbide (Al{sub 4}C{sub 3}) is formed at the interface and traces of TiAl{sub 3} in the wetting assemblies were detected. Scanning Electron Microscopy (SEM) observations show that TiC particles do not appear to be uniformly attacked to produce a continuous layer of Al{sub 4}C{sub 3} at the interface. Molten Al-Mg-alloys were infiltrated into TiC preforms with flowing argon at a temperature of 900 deg. C. In the composites no reaction phase was observed by SEM. Quantification of the Al phase in the composite was carried out by X-ray diffraction (XRD) and Rietveld analysis. Chemical mapping analyzed by SEM shows that the Al-Mg alloy surrounds TiC particles. In the composites with 20 wt.% of Mg the Al-Mg-{beta} phase was detected through XRD.

  7. Enhancement of solar photocatalytic detoxification by adsorption of porphyrins onto TiO sub 2

    SciTech Connect (OSTI)

    Majumder, S.A.; Ondrias, M.R. . Dept. of Chemistry); Prairie, M.R. ); Shelnutt, J.A. . Dept. of Chemistry Sandia National Labs., Albuquerque, NM )

    1991-01-01

    Titanium dioxide (TiO{sub 2}) is a photocatalyst for solar detoxification of water containing organic contaminants such as solvents, PCB's, dioxins, pesticides, and dyes. Unfortunately, the ultraviolet (UV) energy used by TiO{sub 2} ({lambda}<400 nm) only comprises about 4% of the solar spectrum. One way of enhancing the efficiency of solar detoxification technologies is to utilize a larger portion of the solar spectrum to initiate the Tio{sub 2}- catalyzed detoxification chemistry. Metalloporphyrins strongly absorb visible and near infrared radiation. By utilization of a process called photosensitization, adsorption of these dyes onto TiO{sub 2} can enable a much broader portion of the solar spectrum to be used. Photosensitization relies upon the ability of the dye molecule to absorb more of the solar energy than bare TiO{sub 2} and to interact electronically with the TiO{sub 2} surface in such a way as to initiate TiO{sub 2}-based redox photochemistry using the dye-absorbed energy. 16 refs., 7 figs.

  8. Structural Environment of Nitrogen in N-doped Rutile TiO2(110)

    SciTech Connect (OSTI)

    Henderson, Michael A.; Shutthanandan, V.; Ohsawa, Takeo; Chambers, Scott A.

    2010-12-31

    We employ x-ray photoelectron spectroscopy (XPS), reflection high-energy electron diffraction (RHEED) and nuclear reaction analysis (NRA) to characterize the concentration-dependent structural properties of nitrogen doping into rutile TiO2. High quality N-doped TiO2 were prepared on rutile single crystal TiO2(110) substrates using plasma-assisted molecular beam epitaxy with an electron cyclotron resonance (ECR) plasma and Ti effusive sources. Films with N dopant concentrations at or below 2 at.% exhibited predominately substitutional doping based on NRA data, whereas films with concentrations above this limit resulted in little or no substitutional N and surfaces rich in Ti3+. The binding energy of the N 1s feature in XPS did not readily distinguish between these two extremes in N-doping, rendering features within 0.4 eV of each other and similar peak profiles. Although widely used to characterize the state of N in anion-doped TiO2 materials, we find that XPS is unsuitable for this task.

  9. Production of Ni-Cr-Ti-natural fibres composite and investigation of mechanical properties

    SciTech Connect (OSTI)

    Pesmen, G.; Erol, A.

    2015-03-30

    Intermetallic materials such as Ni{sub 2}Ti, Cr{sub 2}Ti are among advanced technology materials that have outstanding mechanical and physical properties for high temperature applications. Especially creep resistance, low density and high hardness properties stand out in such intermetallics. The microstructure, mechanical properties of (%50Ni-%48Cr-%2Ti)-%10Naturel Fibres and (%64Ni-%32Cr-%4Ti)-%10Naturel Fibres powders were investigated using specimens produced by tube furnace sintering at 1000-1200-1400C temperature. A composite consisting of ternary additions, a metallic phase, Ti,Cr and Ni have been prepared under Ar shroud and then tube furnace sintered. XRD, SEM (Scanning Electron Microscope), were investigated to characterize the properties of the specimens. Experimental results carried out for composition (%64Ni-%32Cr-%4Ti)-%10Naturel at 1400C suggest that the best properties as 112.09HV and 5,422g/cm{sup 3} density were obtained at 1400C.

  10. WO3/TiO2 nanotube photoanodes for solar water splitting with simultaneous wastewater treatment.

    SciTech Connect (OSTI)

    Reyes, Karla Rosa; Robinson, David B.

    2013-05-01

    Nanostructured WO3/TiO2 nanotubes with properties that enhance solar photoconversion reactions were developed, characterized and tested. The TiO2 nanotubes were prepared by anodization of Ti foil, and WO3 was electrodeposited on top of the nanotubes. SEM images show that these materials have the same ordered structure as TiO2 nanotubes, with an external nanostructured WO3 layer. Diffuse reflectance spectra showed an increase in the visible absorption relative to bare TiO2 nanotubes, and in the UV absorption relative to bare WO3 films. Incident simulated solar photon-to-current efficiency increased from 30% (for bare WO3) to 50% (for WO3/TiO2 composites). With the addition of diverse organic pollutants, the photocurrent densities exhibited more than a 5-fold increase. Chemical oxygen demand measurements showed the simultaneous photodegradation of organic pollutants. The results of this work indicate that the unique structure and composition of these composite materials enhance the charge carrier transport and optical properties compared with the parent materials.

  11. A Comparative Study of the Water Gas Shift Reaction Over Platinum Catalysts Supported on CeO2, TiO2 and Ce-Modified TiO2

    SciTech Connect (OSTI)

    Gonzalez, I.; Navarro, R; Wen, W; Marinkovic, N; Rodriguez, J; Rosa, F; Fierro, J

    2010-01-01

    WGS reaction has been investigated on catalysts based on platinum supported over CeO{sub 2}, TiO{sub 2} and Ce-modified TiO{sub 2}. XPS and XANES analyses performed on calcined catalysts revealed a close contact between Pt precursors and cerium species on CeO{sub 2} and Ce-modified TiO{sub 2} supports. TPR results corroborate the intimate contact between Pt and cerium entities in the Pt/Ce-TiO{sub 2} catalyst that facilitates the reducibility of the support at low temperatures while the Ce-O-Ti surface interactions established in the Ce-modified TiO{sub 2} support decreases the reduction of TiO{sub 2} at high temperature. The changes in the support reducibility leads to significant differences in the WGS activity of the studied catalysts. Pt supported on Ce-modified TiO{sub 2} support exhibits better activity than those corresponding to individual CeO{sub 2} and TiO{sub 2}-supported catalysts. Additionally, the Ce-TiO{sub 2}-supported catalyst displays better stability at reaction temperatures higher than 573 K that observed on pure TiO{sub 2}-supported counterpart. Activity measurements, when coupled with the physicochemical characterization of catalysts suggest that the modifications in the surface reducibility of the support play an essential role in the enhancement of activity and stability observed when Pt is supported on the Ce-modified TiO{sub 2} substrate.

  12. Supersaturated Al(Ti) solid solutions with partial L1{sub 2} ordering prepared by mechanical alloying

    SciTech Connect (OSTI)

    Fan, G.J.; Quan, M.X.; Hu, Z.Q.

    1995-08-01

    The authors report phase formation during mechanical alloying of Al rich Ti-Al powder blends. Their experimental results further support the idea that the synthesis of Al rich supersaturated solid solutions in the Al-Ti system occurs in the following two steps. First, the ordered L1{sub 2}-Al{sub 3}Ti intermetallic compound is formed at Al/Ti interfaces. Second, the ordered L1{sup 2}-Al{sub 3}Ti compound was partially disordered by mechanical deformation. Meanwhile, Ti or Al atoms dissolve into the partially disordered phase and a supersaturated solid solution is finally obtained. However, the disordering is not complete and the resulting alloys may exhibit partial L1{sub 2} ordering.

  13. Improving the osteointegration of Ti6Al4V by zeolite MFI coating

    SciTech Connect (OSTI)

    Li, Yong; Jiao, Yilai; Li, Xiaokang; Guo, Zheng

    2015-05-01

    Osteointegration is crucial for success in orthopedic implantation. In recent decades, there have been numerous studies aiming to modify titanium alloys, which are the most widely used materials in orthopedics. Zeolites are solid aluminosilicates whose application in the biomedical field has recently been explored. To this end, MFI zeolites have been developed as titanium alloy coatings and tested in vitro. Nevertheless, the effect of the MFI coating of biomaterials in vivo has not yet been addressed. The aim of the present work is to evaluate the effects of MFI-coated Ti6Al4V implants in vitro and in vivo. After surface modification, the surface was investigated using field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). No difference was observed regarding the proliferation of MC3T3-E1 cells on the Ti6Al4V (Ti) and MFI-coated Ti6Al4V (M−Ti) (p > 0.05). However, the attachment of MC3T3-E1 cells was found to be better in the M−Ti group. Additionally, ALP staining and activity assays and quantitative real-time RT-PCR indicated that MC3T3-E1 cells grown on the M−Ti displayed high levels of osteogenic differentiation markers. Moreover, Van-Gieson staining of histological sections demonstrated that the MFI coating on Ti6Al4V scaffolds significantly enhanced osteointegration and promoted bone regeneration after implantation in rabbit femoral condylar defects at 4 and 12 weeks. Therefore, this study provides a method for modifying Ti6Al4V to achieve improved osteointegration and osteogenesis. - Highlights: • Osteointegration is a crucial factor for orthopedic implants. • We coated MFI zeolite on Ti6Al4V substrates and investigated the effects in vitro and in vivo. • The MFI coating displayed good biocompatibility and promoted osteogenic differentiation in vitro. • The MFI coating promoted osteointegration and osteogenesis peri-implant in vivo.

  14. Synthesis and characterization of F-N-W-codoped TiO{sub 2} photocatalyst with enhanced visible light response

    SciTech Connect (OSTI)

    Shi, Xiaoliang; School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 ; Qin, Haibo; Yang, Xingyong; Zhang, Qiaoxin; School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ? Anatase F-N-W-codoped TiO{sub 2} was prepared by a solgel-hydrothermal method. ? Under visible illumination, carbon removal rate of RB reached 94% using F-7NW-TiO{sub 2}. ? F, N and W dopants narrowed band gap and lowed charge pairs recombination rate. ? There were W{sub x}Ti{sub 1?x}O{sub 2}, O-Ti-N and valence variation of W ions existing. -- Abstract: Anatase F-N-W-codoped TiO{sub 2} photocatalyst was successfully prepared by a method combining solgel with hydrothermal treatment. Effects of F, N and W ion dosage concentration on the crystallinity, morphology, grain size and chemical status of the photocatalyst were investigated. The results showed that the F-7NW-TiO{sub 2} photocatalyst composed of uniform ellipsoidal particles around 20 nm in length and 10 nm in width, and the photocatalyst displayed enhanced visible-light absorption and photocatalytic activities. Using the photocatalyst and under visible irradiation for 1.5 h, the decoloration percent of RB and carbon removal rate were about 98% and 94% respectively, which were much higher than that of commercial P25, TiO{sub 2}, N-W-TiO{sub 2} and F-TiO{sub 2}. The high visible-light photocatalytic activity of F-7NW-TiO{sub 2} might result from narrowing the band gap and lowing charge pairs recombination rate for the W{sub x}Ti{sub 1?x}O{sub 2}, O-Ti-N and valence variation of W ions existing.

  15. Metallic glass alloys of Zr, Ti, Cu and Ni

    DOE Patents [OSTI]

    Lin, Xianghong; Peker, Atakan; Johnson, William L.

    1997-01-01

    At least quaternary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10.sup.3 K/s. Such alloys comprise titanium from 19 to 41 atomic percent, an early transition metal (ETM) from 4 to 21 atomic percent and copper plus a late transition metal (LTM) from 49 to 64 atomic percent. The ETM comprises zirconium and/or hafnium. The LTM comprises cobalt and/or nickel. The composition is further constrained such that the product of the copper plus LTM times the atomic proportion of LTM relative to the copper is from 2 to 14. The atomic percentage of ETM is less than 10 when the atomic percentage of titanium is as high as 41, and may be as large as 21 when the atomic percentage of titanium is as low as 24. Furthermore, when the total of copper and LTM are low, the amount of LTM present must be further limited. Another group of glass forming alloys has the formula (ETM.sub.1-x Ti.sub.x).sub.a Cu.sub.b (Ni.sub.1-y Co.sub.y).sub.c wherein x is from 0.1 to 0.3, y.cndot.c is from 0 to 18, a is from 47 to 67, b is from 8 to 42, and c is from 4 to 37. This definition of the alloys has additional constraints on the range of copper content, b.

  16. Fatigue crack growth behavior of Ti-1100 at elevated temperature

    SciTech Connect (OSTI)

    Maxwell, D.C.; Nicholas, T.

    1995-12-31

    Effects of temperature, frequency, and cycles with superimposed hold times are evaluated in Ti-1100 in order to study the complex creep-fatigue-environment interactions in this material. Crack growth rate tests conducted at cyclic loading frequency of 1.0 Hz show that raising the temperature from 593 to 650 C has only a slightly detrimental effect on crack growth rate, although these temperatures produce growth rates significantly higher than at room temperature. From constant {Delta}K tests, the effects of temperature at constant frequency show a minimum crack growth rate at 250 C. From the minimum crack growth rate at 250 C, the crack growth rate increases linearly with temperature. Increases in frequency at constant temperatures of 593 and 650 C produce a continuous decrease in growth rate in going from 0.001 to 1.0 Hz, although the behavior is primarily cycle dependent in this region. Tests at 1.0 Hz with superimposed hold times from 1 to 1,000 s are used to evaluate creep-fatigue-environment interactions. Hold times at maximum load are found to initially decrease and then increase the cyclic crack growth rate with increasing duration. This is attributed to crack-tip blunting during short hold times and environmental degradation at long hold times. Hold times at minimum load show no change in growth rates, indicating that there is no net environmental degradation to the bulk material beyond that experienced during the baseline 1 Hz cycling.

  17. Advancements in Ti Alloy Powder Production by Close-Coupled Gas Atomization

    SciTech Connect (OSTI)

    Heidloff, Andy; Rieken, Joel; Anderson, Iver; Byrd, David

    2011-04-01

    As the technology for titanium metal injection molding (Ti-MIM) becomes more readily available, efficient Ti alloy fine powder production methods are required. An update on a novel close-coupled gas atomization system has been given. Unique features of the melting apparatus are shown to have measurable effects on the efficiency and ability to fully melt within the induction skull melting system (ISM). The means to initiate the melt flow were also found to be dependent on melt apparatus. Starting oxygen contents of atomization feedstock are suggested based on oxygen pick up during the atomization and MIM processes and compared to a new ASTM specification. Forming of titanium by metal injection molding (Ti-MIM) has been extensively studied with regards to binders, particle shape, and size distribution and suitable de-binding methods have been discovered. As a result, the visibility of Ti-MIM has steadily increased as reviews of technology, acceptability, and availability have been released. In addition, new ASTM specification ASTM F2885-11 for Ti-MIM for biomedical implants was released in early 2011. As the general acceptance of Ti-MIM as a viable fabrication route increases, demand for economical production of high quality Ti alloy powder for the preparation of Ti-MIM feedstock correspondingly increases. The production of spherical powders from the liquid state has required extensive pre-processing into different shapes thereby increasing costs. This has prompted examination of Ti-MIM with non-spherical particle shape. These particles are produced by the hydride/de-hydride process and are equi-axed but fragmented and angular which is less than ideal. Current prices for MIM quality titanium powder range from $40-$220/kg. While it is ideal for the MIM process to utilize spherical powders within the size range of 0.5-20 {mu}m, titanium's high affinity for oxygen to date has prohibited the use of this powder size range. In order to meet oxygen requirements the top size

  18. Adsorption, Desorption, and Dissociation of Benzene on TiO2(110) and Pd/TiO2(110)

    SciTech Connect (OSTI)

    Zhou, Jing; Dag, Sefa; Senanayake, Sanjaya D; Hathorn, Bryan C; Kalinin, Sergei V; Meunier, Vincent; Mullins, David R; Overbury, Steven {Steve} H; Baddorf, Arthur P

    2006-01-01

    Adsorption and reaction of benzene molecules on clean TiO{sub 2}(110) and on TiO{sub 2}(110) with deposited Pd nanoparticles are investigated using a combination of scanning tunneling microscopy (STM), temperature-programmed desorption, and first-principles calculations. Above {approx}50 K, the one-dimensional motion of benzene between bridging oxygen rows is shown to be too fast for STM imaging. At 40 K benzene molecules form chains on top of titanium rows, with calculations indicating every other benzene is rotated 30{sup o}. Both experimental and theoretical studies find no dissociative reactivity of benzene on the clean TiO{sub 2}(110) surface, due to little hybridization between TiO{sub 2} and benzene electronic states. After deposition of Pd nanoparticles, molecular benzene is observed with STM both on the substrate and adjacent to metallic particles. Upon heating to 800 K, benzene fully breaks down into its atomic constituents in a multistep decomposition process.

  19. Direct observation of oxygen-vacancy-enhanced polarization in a SrTiO3-buffered ferroelectric BaTiO3 film on GaAs

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Qiao, Q.; Zhang, Y.; Contreras-Guerrero, Rocio; Droopad, Ravi; Pantelides, S. T.; Pennycook, Stephen J.; Ogut, Serdar; Klie, Robert F.

    2015-11-16

    The integration of functional oxide thin-films on compound semiconductors can lead to a class of reconfigurable spin-based optoelectronic devices if defect-free, fully reversible active layers are stabilized. However, previous first-principles calculations predicted that SrTiO3 thin filmsgrown on Si exhibit pinned ferroelectric behavior that is not switchable, due to the presence of interfacial vacancies. Meanwhile, piezoresponse force microscopy measurements have demonstrated ferroelectricity in BaTiO3 grown on semiconductor substrates. The presence of interfacial oxygen vacancies in such complex-oxide/semiconductor systems remains unexplored, and their effect on ferroelectricity is controversial. We also use a combination of aberration-corrected scanning transmission electron microscopy and first-principles densitymore » functional theory modeling to examine the role of interfacial oxygen vacancies on the ferroelectricpolarization of a BaTiO3 thin filmgrown on GaAs. Moreover, we demonstrate that interfacial oxygen vacancies enhance the polar discontinuity (and thus the single domain, out-of-plane polarization pinning in BaTiO3), and propose that the presence of surface charge screening allows the formation of switchable domains.« less

  20. Reactivity Screening of Anatase TiO2 Nanotube Arrays and Anatase Thin Films: A Surface Chemistry Point of View

    SciTech Connect (OSTI)

    Funk, S.; Hokkanen, B.; Nurkic, T.; Goering, J.; Kadossov, E.; Burghaus, Uwe; Ghicov, A.; Schmuki, P.; Yu, Zhongqing; Thevuthasan, Suntharampillai; Saraf, Laxmikant V.

    2008-09-19

    As a reactivity screening we collected thermal desorption spectroscopy (TDS) data of iso-butane, O2, CO2, and CO adsorbed on ordered TiO2 nanotube (TiNTs) arrays. As a reference system iso-butane adsorption on an anatase TiO2 thin film has been considered as well. The as-grown TiNTs are vertically aligned and amorphous. Polycrystalline (poly.) anatase or poly. anatase/rutile mixed nanotubes are formed by annealing confirmed by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The anatase thin film was grown on SrTiO3(001) and characterized by XRD and atomic force microscopy (AFM). Surprisingly, oxygen distinctly interacts with the TiNTs whereas this process is not observed on fully oxidized single crystal rutile TiO2(110). Desorption temperatures of 110-150 K and 100-120 K were observed for CO2 and CO, respectively, on the TiNTs. Variations in the binding energies of the alkanes on TiNTs and anatase thin films also were present, i.e., a structure-activity relationship (SAR) is evident.

  1. Synthesis and characterization of CdS doped TiO{sub 2} nanocrystalline powder: A spectroscopic study

    SciTech Connect (OSTI)

    Thakur, Priya; Chadha, Ridhima; Biswas, Nandita; Sarkar, Sisir K.; Mukherjee, Tulsi; Joshi, Satyawati S.; Kapoor, Sudhir

    2012-07-15

    Graphical abstract: Raman spectra of TiO{sub 2} sample doped with 50% CdS and annealed at 600 C. Highlights: ? Transformation from anatase to rutile is prohibited in doped TiO{sub 2}. ? FTIR study indicates that TiO{sub 2} lattice has been modified in the presence of CdS. ? Raman spectroscopy is found to be more sensitive as compared to XRD. -- Abstract: This report aimed to study the effect of CdS doping in TiO{sub 2} on the phase transformation of TiO{sub 2} from anatase to rutile using X-ray diffraction (XRD) and Raman spectroscopy. CdS-doped TiO{sub 2} nanocomposites have been prepared and characterized using Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). We have observed that contrary to bare TiO{sub 2}, phase transformation of TiO{sub 2} from anatase to rutile is hindered when doped with CdS at high temperature. Raman spectroscopy is found to be more sensitive for detection of the surface of TiO{sub 2} as compared to XRD.

  2. The electronic and optical properties of Eu/Si-codoped anatase TiO{sub 2} photocatalyst

    SciTech Connect (OSTI)

    Lin Yanming; Jiang Zhenyi; Zhang Xiaodong; Hu Xiaoyun; Fan Jun

    2012-03-05

    The electronic and optical properties of Eu/Si-codoped anatase TiO{sub 2} are investigated using the density functional theory. The calculated results show that the synergistic effects of Eu/Si codoping can effectively extend the optical absorption edge, which can lead to higher visible-light photocatalytic activities than pure anatase TiO{sub 2}. To verify the reliability of our calculated results, nanocrystalline Eu/Si-codoped TiO{sub 2} is prepared by a sol-gel-solvothermal method, and the experimental results also indicate that the codoping sample exhibits better absorption performance and higher photocatalytic activities than pure TiO{sub 2}.

  3. The visible light degradation activity and the photocatalytic mechanism of tetra(4-carboxyphenyl) porphyrin sensitized TiO{sub 2}

    SciTech Connect (OSTI)

    Wang, Huigang; Zhou, Dongmei; Wu, Zhangzhu; Wan, Junmin; Zheng, Xuming; Yu, Lihong; Phillips, David Lee

    2014-09-15

    Highlights: Tetra(4-carboxyphenyl) porphyrin were chemically sensitized on TiO{sub 2}. S2S0 fluorescence intensity is enhanced and lifetime prolonged noticeably by TiO{sub 2}. The TCPP-TiO{sub 2} exhibits better photoactivity under visible light than that of TiO{sub 2}. The electronic relaxation dynamics is presented, catalytic mechanism is discussed. Adsorption and photo degradation of MB were systematically investigated. - Abstract: Tetra(4-carboxyphenyl) porphyrin(TCPP) were chemically sensitized on TiO{sub 2} to act as visible light antenna and to modify the photoresponse properties of TiO{sub 2} particles, their properties of photo-generated holes and electrons were studied by transient absorption spectroscopes. The time-correlated single-photon counting (TCSPC) technique revealed that the S2S0 fluorescence intensity of TCPP is enhanced noticeably by TiO{sub 2}, and the lifetime prolonged. Adsorption and photo degradation of methylene blue (MB) over TCPP-TiO{sub 2} were systematically investigated. Moreover the overall picture of electronic relaxation dynamics for TCPP-TiO{sub 2} is presented, and the detailed short-time dynamics for visible-light induced catalytic mechanism was discussed. The development of the porphyrin-based photocatalyst provides an alternative approach in harnessing solar visible light and show promising prospect for the treatment of dye pollutants from wastewaters in future industrial application.

  4. A study of photocatalytic grapheneTiO{sub 2} synthesis via peroxo titanic acid refluxed sol

    SciTech Connect (OSTI)

    Low, Wasu; Boonamnuayvitaya, Virote

    2013-08-01

    Graphical abstract: - Highlights: TiO{sub 2} synthesized via PTA as a precursor demonstrates exclusively anatase phase. The TEM image of GRTiO{sub 2} (PTA) demonstrates that TiO{sub 2} nanoparticles are successfully loaded onto graphene sheet. The specific surface area seems to increase with increasing weight ratio of graphene oxide. It was observed that GRTiO{sub 2} showed higher adsorption compared to bare TiO{sub 2} (PTA). The GRTiO{sub 2} (PTA, 1:50) catalyst showed higher photocatalytic activity than any other catalyst. - Abstract: In the present work, grapheneTiO{sub 2} (GRTiO{sub 2}) photocatalyst with various weight ratios of graphene was synthesized using peroxo titanic acid solution (PTA) as a precursor for TiO{sub 2}. Graphene oxide prepared by Hummer's method was converted to graphene under ultraviolet (UV) irradiation in ethanolwater solvent for 48 h. The as-prepared GRTiO{sub 2} composites were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UVvis spectrophotometry, and transmission electron microscopy (TEM). The automated potentiostat was applied to measure the photocurrent generations of prepared catalysts. The photocatalytic activities of GRTiO{sub 2} (PTA) catalysts were determined by measuring the percentage methylene blue (MB) degradation. The results showed that TiO{sub 2} nanoparticles were successfully loaded onto graphene sheet and the surface area of catalysts increased with increasing weight ratio of graphene. In addition, GRTiO{sub 2} (PTA, 1:50) exhibited the highest photocatalytic activity among the catalysts under UV and visible light irradiation. The adsorption edge of GRTiO{sub 2} was shifted to a longer wavelength of 400 nm in comparison with that of pure TiO{sub 2} (PTA). The increase in the photocatalytic performance of GRTiO{sub 2} (PTA) catalyst may be attributed to the increase in surface area, the extension of light absorption in the visible light region, and

  5. A New Method of Low Cost Production of Ti Alloys to Reduce Energy Cpnsumption of Mechanical Systems

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Zak Fang, PI, University of Utah, U.S. DOE Advanced Manufacturing Office Peer Review Meeting Washington, D.C. May 6-7, 2014 This presentation does not contain any proprietary, confidential, or otherwise restricted information. Project Objective  Develop a novel low cost method for manufacturing Ti  Demonstrate the mechanical properties of Ti using the new method to be equivalent to that of wrought Ti at a fraction of its cost.  Demonstrate advantages of using Ti (by this technology) in

  6. The study of crack resistance of TiAlN coatings under mechanical loading and thermal cycle testing

    SciTech Connect (OSTI)

    Akulinkin, Alexandr Shugurov, Artur Sergeev, Viktor; Panin, Alexey; Cheng, C.-H.

    2015-10-27

    The effect of preliminary ion bombardment of 321 stainless steel substrate on crack resistance of TiAlN coatings at uniaxial tension and thermal cycling is studied. The ion-beam treatment of the substrate is shown to substantially improve the adhesion strength of the coatings that prevents their delamination and spalling under uniaxial tension. The resistance to crack propagation and spalling by the thermal shock is higher in the TiAlN coating deposited onto the substrate subjected to Ti ion bombardment as compared to that in the TiAlN coating deposited onto the initial substrate.

  7. Structure of epitaxial (Fe,N) codoped rutile TiO2 thin films by x-ray absorption

    SciTech Connect (OSTI)

    Kaspar, Tiffany C.; Ney, A.; Mangham, Andrew N.; Heald, Steve M.; Joly, Yves; Ney, V.; Wilhelm, F.; Rogalev, A.; Yakou, Flora; Chambers, Scott A.

    2012-07-23

    Homoepitaxial thin films of Fe:TiO2 and (Fe,N):TiO2 were deposited on rutile(110) by molecular beam epitaxy. X-ray absorption near edge spectroscopy (XANES) spectra were collected at the Ti L-edge, Fe L-edge, O K-edge, N K-edge, and Ti K-edge. No evidence of structural disorder associated with a high concentration of oxygen vacancies is observed. Substitution of Fe for Ti could not be confirmed, although secondary phase Fe2O3 and metallic Fe can be ruled out. The similarity of the N K-edge spectra to O, and the presence of a strong x-ray linear dichroism (XLD) signal for the N K-edge, indicates that N is substitutional for O in the rutile lattice, and is not present as a secondary phase such as TiN. Simulations of the XANES spectra qualitatively confirm substitution, although N appears to be present in more than one local environment. Neither Fe:TiO2 nor (Fe,N):TiO2 exhibit intrinsic room temperature ferromagnetism, despite the presence of mixed valence Fe(II)/Fe(III) in the reduced (Fe,N):TiO2 film.

  8. Micro- and nano-scale hollow TiO{sub 2} fibers by coaxial electrospinning: Preparation and gas sensing

    SciTech Connect (OSTI)

    Zhang Jin; Choi, Sun-Woo; Kim, Sang Sub

    2011-11-15

    We report the preparation of micro- and nano-scale hollow TiO{sub 2} fibers using a coaxial electrospinning technique and their gas sensing properties in terms of CO. The diameter of hollow TiO{sub 2} fibers can be controlled from 200 nm to several micrometers by changing the viscosity of electrospinning solutions. Lower viscosities produce slim hollow nanofibers. In contrast, fat hollow microfibers are obtained in the case of higher viscosities. A simple mathematical expression is presented to predict the change in diameter of hollow TiO{sub 2} fibers as a function of viscosity. The successful control over the diameter of hollow TiO{sub 2} fibers is expected to bring extensive applications. To test a potential use of hollow TiO{sub 2} fibers in chemical gas sensors, their sensing properties to CO are investigated at room temperature. - Graphical abstract: Microstructures of as-prepared and calcined hollow TiO{sub 2} fibers prepared by the electrospinning technique with a coaxial needle. Dynamic response at various CO concentrations for the sensor fabricated with the hollow TiO{sub 2} fibers. Highlights: > Hollow TiO{sub 2} fibers were synthesized using a coaxial electrospinning technique. > Their diameter can be controlled by changing the viscosity of electrospinning solutions. > Lower viscosities produce slim hollow nanofibers. > In contrast, fat hollow microfibers are obtained in the case of higher viscosities. > Successful control over the diameter of hollow TiO{sub 2} fibers will bring extensive applications.

  9. Synthesis and characterization of zinc doped nano TiO{sub 2} for efficient photocatalytic degradation of Eriochrome Black T

    SciTech Connect (OSTI)

    Singla, Pooja; Singh, Kulvir; Pandey, O. P.; Sharma, Manoj

    2013-06-03

    Sol-gel method was used to synthesize undoped and zinc doped TiO{sub 2} with varied dopant concentrations using titanium tetraisopropoxide and zinc acetate as precursors. The synthesized catalyst samples were characterized by various techniques such as X-ray powder diffraction (XRD), UV-vis diffuse reflectance (DRS). The photocatalytic activity was determined by means of degradation of azo dye Eriochrome Black T. The results revealed that Zn doped TiO{sub 2} nanoparticles exhibited better results as compared to undoped TiO{sub 2} nanoparticles. Zn doped TiO{sub 2} (0.7mol %) nanoparticles exhibited the highest photocatalytic activity.

  10. Thermal conductivity of nitride films of Ti, Cr, and W deposited by reactive magnetron sputtering

    SciTech Connect (OSTI)

    Jagannadham, Kasichainula

    2015-05-15

    Nitride films of Ti, Cr, and W were deposited using reactive magnetron sputtering from metal targets in argon and nitrogen plasma. TiN films with (200) orientation were achieved on silicon (100) at the substrate temperature of 500 and 600?C. The films were polycrystalline at lower temperature. An amorphous interface layer was observed between the TiN film and Si wafer deposited at 600?C. TiN film deposited at 600?C showed the nitrogen to Ti ratio to be near unity, but films deposited at lower temperature were nitrogen deficient. CrN film with (200) orientation and good stoichiometry was achieved at 600?C on Si(111) wafer but the film deposited at 500?C showed cubic CrN and hexagonal Cr{sub 2}N phases with smaller grain size and amorphous back ground in the x-ray diffraction pattern. An amorphous interface layer was not observed in the cubic CrN film on Si(111) deposited at 600?C. Nitride film of tungsten deposited at 600?C on Si(100) wafer was nitrogen deficient, contained both cubic W{sub 2}N and hexagonal WN phases with smaller grain size. Nitride films of tungsten deposited at 500?C were nonstoichiometric and contained cubic W{sub 2}N and unreacted W phases. There was no amorphous phase formed along the interface for the tungsten nitride film deposited at 600?C on the Si wafer. Thermal conductivity and interface thermal conductance of all the nitride films of Ti, Cr, and W were determined by transient thermoreflectance technique. The thermal conductivity of the films as function of deposition temperature, microstructure, nitrogen stoichiometry and amorphous interaction layer at the interface was determined. Tungsten nitride film containing both cubic and hexagonal phases was found to exhibit much higher thermal conductivity and interface thermal conductance. The amorphous interface layer was found to reduce effective thermal conductivity of TiN and CrN films.

  11. Efficient H{sub 2} production over Au/graphene/TiO{sub 2} induced by surface plasmon resonance of Au and band-gap excitation of TiO{sub 2}

    SciTech Connect (OSTI)

    Liu, Yang; Yu, Hongtao; Wang, Hua; Chen, Shuo; Quan, Xie

    2014-11-15

    Highlights: Both surface plasmon resonance and band-gap excitation were used for H{sub 2} production. Au/Gr/TiO{sub 2} composite photocatalyst was synthesized. Au/Gr/TiO{sub 2} exhibited enhancement of light absorption and charge separation. H{sub 2} production rate of Au/Gr/TiO{sub 2} was about 2 times as high as that of Au/TiO{sub 2}. - Abstract: H{sub 2} production over Au/Gr/TiO{sub 2} composite photocatalyst induced by surface plasmon resonance of Au and band-gap excitation of TiO{sub 2} using graphene (Gr) as an electron acceptor has been investigated. Electron paramagnetic resonance study indicated that, in this composite, Gr collected electrons not only from Au with surface plasmon resonance but also from TiO{sub 2} with band-gap excitation. Surface photovoltage and UVvis absorption measurements revealed that compared with Au/TiO{sub 2}, Au/Gr/TiO{sub 2} displayed more effective photogenerated charge separation and higher optical absorption. Benefiting from these advantages, the H{sub 2} production rate of Au/Gr/TiO{sub 2} composite with Gr content of 1.0 wt% and Au content of 2.0 wt% was about 2 times as high as that of Au/TiO{sub 2}. This work represents an important step toward the efficient application of both surface plasmon resonance and band-gap excitation on the way to converting solar light into chemical energy.

  12. Microstructure and tribological performance of nanocomposite Ti-Si-C-N coatings deposited using hexamethyldisilazane precursor

    SciTech Connect (OSTI)

    Wei Ronghua; Rincon, Christopher; Langa, Edward; Yang Qi

    2010-09-15

    Thick nanocomposite Ti-Si-C-N coatings (20-30 {mu}m) were deposited on Ti-6Al-4V substrate by magnetron sputtering of Ti in a gas mixture of Ar, N{sub 2}, and hexamethyldisilazane (HMDSN) under various deposition conditions. Microstructure and composition of the coatings were studied using scanning electron microscopy, x-ray diffraction, and energy dispersive x-ray spectroscopy, while the mechanical and tribological properties of these coatings were studied using Rc indentation, and micro- and nanoindentations, solid particle erosion testing, and ball-on-disk wear testing. It has been observed that the Si concentration of these coatings is varied from 0% (TiN) to 15% (Ti-Si-C-N), while the structure of these coatings is similar to the nanocomposite Ti-Si-N coatings and consists of nanocrystalline B1 structured Ti(C,N) in an amorphous matrix of SiC{sub x}N{sub y} with the grain size of 5->100 nm, depending on the coating preparation process. These coatings exhibit excellent adhesion when subjected to Rc indentation tests. The microhardness of these coatings varies from 1200 to 3400 HV25, while the nanohardness varies from 10 to 26 GPa. Both the microhardness and nanohardness are slightly lower than those of similar coatings prepared using trimethylsilane. However, the erosion test using a microsand erosion tester at both 30 deg. and 90 deg. incident angles shows that these coatings have very high erosion resistance and up to a few hundred times of improvement has been observed. These coatings also exhibit very high resistance to sliding wear with a low coefficient of friction of about 0.2 in dry sliding. There are a few advantages of using the HMDSN precursor to prepare the Ti-Si-C-N coatings over conventional magnetron sputtered deposition of Ti-Si-N coatings including composition uniformity, precursor handling safety, and high deposition rate. The coatings can be applied to protect gas turbine compressor blades from solid particle erosion and steam turbine blades

  13. Deformation and fracture behavior of composite structured Ti-Nb-Al-Co(-Ni) alloys

    SciTech Connect (OSTI)

    Okulov, I. V. Marr, T.; Schultz, L.; Eckert, J.; Khn, U.; Freudenberger, J.; Oertel, C.-G.; Skrotzki, W.

    2014-02-17

    Tensile ductility of the Ti-based composites, which consist of a ?-Ti phase surrounded by ultrafine structured intermetallics, is tunable through the control of intermetallics. The two Ti-based alloys studied exhibit similar compressive yield strength (about 1000?MPa) and strain (about 35%40%) but show a distinct difference in their tensile plasticity. The alloy Ti{sub 71.8}Nb{sub 14.1}Ni{sub 7.4}Al{sub 6.7} fractures at the yield stress while the alloy Ti{sub 71.8}Nb{sub 14.1}Co{sub 7.4}Al{sub 6.7} exhibits about 4.5% of tensile plastic deformation. To clarify the effect of microstructure on the deformation behavior of these alloys, tensile tests were carried out in the scanning electron microscope. It is shown that the distribution as well as the type of intermetallics affects the tensile ductility of the alloys.

  14. Coreshell TiO? microsphere with enhanced photocatalytic activity and improved lithium storage

    SciTech Connect (OSTI)

    Guo, Hong; Tian, Dongxue; Liu, Lixiang; Wang, Yapeng; Guo, Yuan; Yang, Xiangjun

    2013-05-01

    Inorganic hollow coreshell spheres have attracted considerable interest due to their singular properties and wide range of potential applications. Herein a novel facile generic strategy of combining template assisted and solvothermal alcoholysis is employed to prepare corevoidshell anatase TiO? nanoparticle aggregates with an excellent photocatalytic activity, and enhanced lithium storage in large quantities. Amorphous carbon can be loaded on the TiO? nanoparticles uniformly under a suitably formulated ethanol/water system in the solvothermal alcoholysis process, and the subsequent calcination results of the formation of coreshellshell anatase TiO? nanoparticle aggregates. The intrinsic corevoidshell nature as well as high porosity of the unique nanostructures contributes greatly to the superior photocatalytic activity and improved performance as anode materials for lithium ion batteries. - Graphical abstract: A novel strategy of combining template assisted and solvothermal alcoholysis is employed to prepare unique corevoidshell anatase TiO? nanoparticle aggregates with the superior photocatalytic activity and improved lithium storage. Highlights: TiO? mesospheres are synthesized by solvothermal alcoholysis. It is corevoidshell structure and the thickness of shell is estimated to 80 nm. It exhibits a remarkable photocatalytic activity and improved lithium storage.

  15. Synthesis and Characterization of Photocatalytic TiO 2 -ZnFe 2 O 4 Nanoparticles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Srinivasan, Sesha S.; Wade, Jeremy; Stefanakos, Elias K.

    2006-01-01

    A new coprecipimore » tation/hydrolysis synthesis route is used to create a TiO 2 -ZnFe 2 O 4 nanocomposite that is directed towards extending the photoresponse of TiO 2 from UV to visible wavelengths ( > 400   nm ). The effect of TiO 2 's accelerated anatase-rutile phase transformation due to the presence of the coupled ZnFe 2 O 4 narrow-bandgap semiconductor is evaluated. The transformation's dependence on pH, calcinations temperature, particle size, and ZnFe 2 O 4 concentration has been analyzed using XRD, SEM, and UV-visible spectrometry. The requirements for retaining the highly photoactive anatase phase present in a ZnFe 2 O 4 nanocomposite are outlined. The visible-light-activated photocatalytic activity of the TiO 2 -ZnFe 2 O 4 nanocomposites has been compared to an Aldrich TiO 2 reference catalyst, using a solar-simulated photoreactor for the degradation of phenol.« less

  16. Synthesis and Characterization of PhotocatalyticTiO2-ZnFe2O4Nanoparticles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Srinivasan, Sesha S.; Wade, Jeremy; Stefanakos, Elias K.

    2006-01-01

    A new coprecipitation/hydrolysis synthesis route is used to create aTiO2-ZnFe2O4nanocomposite that is directed towards extending the photoresponse ofTiO2from UV to visible wavelengths (>400?nm). The effect ofTiO2's accelerated anatase-rutile phase transformation due to the presence of the coupledZnFe2O4narrow-bandgap semiconductor is evaluated. The transformation's dependence on pH, calcinations temperature, particle size, andZnFe2O4concentration has been analyzed using XRD, SEM, and UV-visible spectrometry. The requirements for retaining the highly photoactive anatase phase present in aZnFe2O4nanocomposite are outlined. The visible-light-activated photocatalytic activity of theTiO2-ZnFe2O4nanocomposites has been compared to an AldrichTiO2reference catalyst, using a solar-simulated photoreactor formorethe degradation of phenol.less

  17. Significant increase of Curie temperature in nano-scale BaTiO{sub 3}

    SciTech Connect (OSTI)

    Li, Yueliang; Liao, Zhenyu; Fang, Fang; Zhu, Jing; Wang, Xiaohui; Li, Longtu

    2014-11-03

    The low Curie temperature (T{sub c}?=?130?C) of bulk BaTiO{sub 3} greatly limits its applications. In this work, the phase structures of BaTiO{sub 3} nanoparticles with sizes ranging from 2.5?nm to 10?nm were studied at various temperatures by using aberration-corrected transmission electron microscopy (TEM) equipped with an in-situ heating holder. The results implied that each BaTiO{sub 3} nanoparticle was composed of different phases, and the ferroelectric ones were observed in the shells due to the complicated surface structure. The ferroelectric phases in BaTiO{sub 3} nanoparticles remained at 600?C, suggesting a significant increase of T{sub c}. Based on the in-situ TEM results and the data reported by others, temperature-size phase diagrams for BaTiO{sub 3} particles and ceramics were proposed, showing that the phase transition became diffused and the T{sub c} obviously increased with decreasing size. The present work sheds light on the design and fabrication of advanced devices for high temperature applications.

  18. First-principles study on negative thermal expansion of PbTiO{sub 3}

    SciTech Connect (OSTI)

    Wang, Fangfang; Chen, Jun; Xing, Xianran; Xie, Ying; Fu, Honggang

    2013-11-25

    It is well known that perovskite-type PbTiO{sub 3} behaves negative thermal expansion in a wide temperature range from room temperature to Curie temperature (763?K). The present study reports the first-principles study of the anisotropic thermal expansion of PbTiO{sub 3}, in the framework of the density-functional theory and the density-functional perturbation theory. The curve of temperature dependence of the unit cell volume is presented from 20 to 520?K through the calculation of the minimum of total free energy at each temperature point. The negative thermal expansion of PbTiO{sub 3} is calculated without empirical parameters. Furthermore, the distinctive thermodynamic act of PbTiO{sub 3} from expanding to contracting at tetragonal phase is reproduced. The ab-initio calculations reveal that this unique appearance depends on the phonon vibration. The dynamical contributions of various atoms are also calculated to account for the disparate role of Pb-O and Ti-O bond.

  19. Femtosecond laser-induced periodic surface structure on the Ti-based nanolayered thin films

    SciTech Connect (OSTI)

    Petrovi?, Suzana M.; Gakovi?, B.; Peruko, D.; Stratakis, E.; Department of Materials Science and Technology, University of Crete, 710 03 Heraklion, Crete ; Bogdanovi?-Radovi?, I.; ?ekada, M.; Fotakis, C.; Department of Physics, University of Crete, 714 09 Heraklion, Crete ; Jelenkovi?, B.

    2013-12-21

    Laser-induced periodic surface structures (LIPSSs) and chemical composition changes of Ti-based nanolayered thin films (Al/Ti, Ni/Ti) after femtosecond (fs) laser pulses action were studied. Irradiation is performed using linearly polarized Ti:Sapphire fs laser pulses of 40 fs pulse duration and 800 nm wavelength. The low spatial frequency LIPSS (LSFL), oriented perpendicular to the laser polarization with periods slightly lower than the irradiation wavelength, was typically formed at elevated laser fluences. On the contrary, high spatial frequency LIPSS (HSFL) with uniform period of 155 nm, parallel to the laser light polarization, appeared at low laser fluences, as well as in the wings of the Gaussian laser beam distribution for higher used fluence. LSFL formation was associated with the material ablation process and accompanied by the intense formation of nanoparticles, especially in the Ni/Ti system. The composition changes at the surface of both multilayer systems in the LSFL area indicated the intermixing between layers and the substrate. Concentration and distribution of all constitutive elements in the irradiated area with formed HSFLs were almost unchanged.

  20. A new phase in rapidly solidified Ti[sub 3]Al-based alloys

    SciTech Connect (OSTI)

    Xu Rui; Xu Daming; Li Qingchun . Dept. of Materials Science and Engineering); Li Dong; Cui Yuyou; Hu Zhuangqi . State Key Lab. for RSA)

    1995-01-15

    Rapid solidification processing has been developed to improve the properties of alloys through refining microstructures, disordering and forming metastable phases. The as-melt spun Ti[sub 3]Al-based alloy with Nb additions above 5-at%, which consist of [alpha][sub 2] and [beta][sub 0] phases in a normal condition, exhibited as single [beta][sub 0] structure. Jackson et al have carried out a comparative study of I/M and RS Ti[sub 3]Al-1 Zr(at%) alloy. Their study revealed that considerable refinement of grains and anti-phase domains was achieved in the rapidly solidified material prepared by the pendant drop melt extraction process (PDME). It is suggested that rapid solidification processing can reduce the ordering of the Ti[sub 3]Al-based alloy. In the past years, it was found that the Ti[sub 3]Al-based alloy with alloying additions (mainly Nb) has been studied extensively, and some new phases such as T and O have been observed in the alloys, but less attention has been given to alloys with low Nb additions. The RS Ti[sub 3]Al-base alloys with Nb below 5-at% have been investigated systematically and a new metastable phase, ordering martensite [alpha][double prime][sub 0] (orthogonal), has been observed in these alloys.

  1. Investigation of the phase equilibrium of alloys of the ternary system Ti-Al-Nb

    SciTech Connect (OSTI)

    Nartova, T.T.; Sopochkin, G.G.

    1987-09-09

    This investigation of the constitution diagram of the ternary system titanium-aluminum-niobium is limited to the specific system Ti-Ti3A1-Nb in order to establish the regions of the alpha and beta solid solutions of titanium, the solid solutions based on aluminide Ti3A1, and the phases conjugated with them. The constitution diagram of the systems Ti-A1 and Ti-Nb obtained from the data were used as the basis for constructing the constitution diagram of the ternary system. The methods of microstructural, thermal and X ray phase analysis were used in the study. The X ray pictures were taken in copper emission from powders that had been preliminarily annealed in a vacuum at 600 for 30 min. Iodic titanium, aluminum brand AV-000 and fillet niobium were used as the source materials. The alloys were remelted five times in an electric-arc furnace with a nonconsumable tungsten electrode in an argon atmosphere, and then by crucibleless melting in the suspended state. The constancy of the chemical composition of the alloys was monitored by their weight after smelting in an electric arc furnace.

  2. Crystallization study of amorphous sputtered NiTi bi-layer thin film

    SciTech Connect (OSTI)

    Mohri, Maryam; Nili-Ahmadabadi, Mahmoud; Chakravadhanula, Venkata Sai Kiran

    2015-05-15

    The crystallization of Ni-rich/NiTiCu bi-layer thin film deposited by magnetron sputtering from two separate alloy targets was investigated. To achieve the shape memory effect, the NiTi thin films deposited at room temperature with amorphous structure were annealed at 773 K for 15, 30, and 60 min for crystallization. Characterization of the films was carried out by differential scanning calorimetry to indicate the crystallization temperature, grazing incidence X-ray diffraction to identify the phase structures, atomic force microscopy to evaluate surface morphology, scanning transmission electron microscopy to study the cross section of the thin films. The results show that the structure of the annealed thin films strongly depends on the temperature and time of the annealing. Crystalline grains nucleated first at the surface and then grew inward to form columnar grains. Furthermore, the crystallization behavior was markedly affected by composition variations. - Highlights: • A developed bi-layer Ni45TiCu5/Ni50.8Ti was deposited on Si substrate and crystallized. • During crystallization, The Ni{sub 45}TiCu{sub 5} layer is thermally less stable than the Ni-rich layer. • The activation energy is 302 and 464 kJ/mol for Cu-rich and Ni-rich layer in bi-layer, respectively.

  3. Influence of rare earth doping on thermoelectric properties of SrTiO{sub 3} ceramics

    SciTech Connect (OSTI)

    Liu, J. Wang, C. L.; Li, Y.; Su, W. B.; Zhu, Y. H.; Li, J. C.; Mei, L. M.

    2013-12-14

    Thermoelectric properties of SrTiO{sub 3} ceramics, doped with different rare earth elements, were investigated in this work. It's found that the ionic radius of doping elements plays an important role on thermoelectric properties: SrTiO{sub 3} ceramics doped with large rare earth ions (such as La, Nd, and Sm) exhibit large power factors, and those doped with small ions (such as Gd, Dy, Er, and Y) exhibit low thermal conductivities. Therefore, a simple approach for enhancing the thermoelectric performance of SrTiO{sub 3} ceramics is proposed: mainly doped with large ions to obtain a large power factor and, simultaneously, slightly co-doped with small ions to obtain a low thermal conductivity. Based on this rule, Sr{sub 0.8}La{sub 0.18}Yb{sub 0.02}TiO{sub 3} ceramics were prepared, whose ZT value at 1 023 K reaches 0.31, increasing by a factor of 19% compared with the single-doped counterpart Sr{sub 0.8}La{sub 0.2}TiO{sub 3} (ZT = 0.26)

  4. Localized states induced by an oxygen vacancy in rutile TiO{sub 2}

    SciTech Connect (OSTI)

    Lin, Chungwei; Shin, Donghan; Demkov, Alexander A.

    2015-06-14

    Using density functional theory and model Hamiltonian analysis, we investigate the localized states induced by an oxygen vacancy in rutile TiO{sub 2}. We identify two classes of localized states—the hybrid and the polaron. The hybrid state is caused by the orbital overlap between three Ti atoms next to a vacancy and is mainly derived from the Ti e{sub g} orbitals. The polaron state is caused by the local lattice distortion and is mainly composed of one particular t{sub 2g} orbital from a single Ti atom. The first principles calculation shows that the polaron state is energetically favored, and the tight-binding analysis reveals the underlying connection between the bulk band structure and the orbital character of the polaron. The magnetic coupling between two nearby polaron states is found to be ferromagnetic. Using this picture, we analyze the results of recent theoretical calculations and experiments and discuss the connection to vacancies in SrTiO{sub 3}.

  5. Molecular and Dissociative Adsorption of Water on (TiO 2 ) n Clusters, n = 1–4

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chen, Mingyang; Straatsma, Tjerk P.; Dixon, David A.

    2015-10-20

    In the low energy structures of the (TiO2)n(H2O)m (n ≤ 4, m ≤ 2n) and (TiO2)8(H2O)m (m = 3, 7, 8) clusters were predicted using a global geometry optimization approach, with a number of new lowest energy isomers being found. Water can molecularly or dissociatively adsorb on pure and hydrated TiO2 clusters. Dissociative adsorption is the dominant reaction for the first two H2O adsorption reactions for n = 1, 2, and 4, for the first three H2O adsorption reactions for n = 3, and for the first four H2O adsorption reactions for n = 8. As more H2O’s are addedmore » to the hydrated (TiO2)n cluster, dissociative adsorption becomes less exothermic as all the Ti centers become 4-coordinate. Furthermore two types of bonds can be formed between the molecularly adsorbed water and TiO2 clusters: a Lewis acid–base Ti–O(H2) bond or an O···H hydrogen bond. The coupled cluster CCSD(T) results show that at 0 K the H2O adsorption energy at a 4-coordinate Ti center is ~15 kcal/mol for the Lewis acid–base molecular adsorption and ~7 kcal/mol for the H-bond molecular adsorption, in comparison to that of 8–10 kcal/mol for the dissociative adsorption. The cluster size and geometry independent dehydration reaction energy, ED, for the general reaction 2(-TiOH) → -TiOTi– + H2O at 4-coordinate Ti centers was estimated from the aggregation reaction of nTi(OH)4 to form the monocyclic ring cluster (TiO3H2)n + nH2O. ED is estimated to be -8 kcal/mol, showing that intramolecular and intermolecular dehydration reactions are intrinsically thermodynamically allowed for the hydrated (TiO2)n clusters with all of the Ti centers 4-coordinate, which can be hindered by cluster geometry changes caused by such processes. Finally by bending force constants for the TiOTi and OTiO bonds are determined to be 7.4 and 56.0 kcal/(mol·rad2). Infrared vibrational spectra were calculated using density functional theory, and the new bands appearing upon water adsorption were assigned.« less

  6. Hydrothermal crystallization of Na{sub 2}Ti{sub 6}O{sub 13}, Na{sub 2}Ti{sub 3}O{sub 7}, and Na{sub 16}Ti{sub 10}O{sub 28} in the NaOH-TiO{sub 2}-H{sub 2}O system at a temperature of 500 deg. C and a pressure of 0.1 GPa: The structural mechanism of self-assembly of titanates from suprapolyhedral clusters

    SciTech Connect (OSTI)

    Hyushin, G. D.

    2006-07-15

    An increase in the NaOH concentration in the NaOH-TiO{sub 2} (rutile)-H{sub 2}O system at a temperature of 500 deg. C and a pressure of 0.1 GPa leads to the crystallization R-TiO{sub 2} + Na{sub 2}Ti{sub 6}O{sub 13} {sup {yields}} Na{sub 2}Ti{sub 3}O{sub 7} {sup {yields}} Na{sub 16}Ti{sub 10}O{sub 28}. Crystals of the Na{sub 2}Ti{sub 6}O{sub 13} titanate (space group C2/m) have the three-dimensional framework structure Ti{sub 6}O{sub 13}. The structure of the Na{sub 2}Ti{sub 3}O{sub 7} titanate (space group P2{sub 1}/m) contains the two-dimensional layers Ti{sub 3}O{sub 7}. The structure of the Na{sub 16}Ti{sub 10}O{sub 28} titanate (space group P-1) is composed of the isolated ten-polyhedron cluster precursors Ti{sub 10}O{sub 28}. In all the structures, the titanium atoms have an octahedral coordination (MTiO{sub 6}). The matrix self-assembly of the Na{sub 2}Ti{sub 6}O{sub 13} and Na{sub 2}Ti{sub 3}O{sub 7} (Na{sub 4}Ti{sub 6}O{sub 14}) crystal structures from Na{sub 4}M{sub 12} invariant precursors is modeled. These precursors are clusters consisting of twelve M polyhedra linked through the edges. It is demonstrated that the structurally rigid precursors Na{sub 4}M{sub 12} control all processes of the subsequent evolution of the crystal-forming titanate clusters. The specific features of the self-assembly of the Na{sub 2}Ti{sub 3}O{sub 7} structure that result from the additional incorporation of twice the number of sodium atoms into the composition of the high-level clusters are considered.

  7. Study of new states in visible light active W, N co-doped TiO{sub 2} photo catalyst

    SciTech Connect (OSTI)

    Sajjad, Ahmed Khan Leghari; Shamaila, Sajjad; Zhang, Jinlong

    2012-11-15

    Highlights: ? Visible light efficient W, N co-doped TiO{sub 2} photo catalysts are prepared by solgel. ? Oxygen vacancies are detected in the form of new linkages as N-Ti-O, N-W-O, Ti-O-N and W-O-N. ? W, N co-doped titania has new energy states which narrows the band gap effectively. ? Oxygen vacancies are proved to be the cause for high photo catalytic activity. ? W and N co-doping plays the major role to make the composite thermally stable. -- Abstract: The visible light efficient W, N co-doped TiO{sub 2} photo catalysts are prepared by solgel method. New linkages of N, W and O are formed as N-Ti-O, N-W-O, Ti-O-N and W-O-N. Electron paramagnetic resonance illustrates the presence of oxygen vacancies in W, N co-doped TiO{sub 2} acting as trapping agencies for electrons to produce active species. X-ray photoelectron spectroscopy confirms the presence of new energy states. New linkages and oxygen vacancies are proved to be the main cause for the improved photo catalytic performances. W, N co-doped TiO{sub 2} has new energy states which narrow the band gap effectively. W, N co-doped TiO{sub 2} is thermally stable and retains its anatase phase up to 900 C. 4.5% W, N co-doped TiO{sub 2} showed superior activity for the degradation of Rhodamine B and 2,4-dichlorophenol as compared to pure titania, Degussa P-25, traditional N-doped TiO{sub 2} and pure WO{sub 3}.

  8. Dielectric and photocatalytic properties of sulfur doped TiO{sub 2} nanoparticles prepared by ball milling

    SciTech Connect (OSTI)

    Jalalah, Mohammed; Faisal, M.; Bouzid, Houcine; Ismail, Adel A.; Al-Sayari, Saleh A.

    2013-09-01

    Graphical abstract: - Highlights: Designing of visible light responsive photocatalyst utilizing ball milling. Sulphur used as dopant in commercial TiO{sub 2} P25 at different atomic percentage. S doping resulted in an intense increase in absorption in the visible light region. Newly design photocatalyst exhibited excellent photocatalytic performance. 0.11 at.% S-doped TiO{sub 2} shows 3-times higher activity than that of TiO{sub 2} P25. - Abstract: Sulfur (S) doped commercial TiO{sub 2} P-25 has been achieved by changing the amount of thiourea using ball milling technique. The results of XRD clearly reveal biphasial anatase and rutile mixtures for all prepared samples and doping of S does not change the morphology of the TiO{sub 2}. The optical absorption edge of S-doped TiO{sub 2} was red shifted with indirect bandgap energy of 2.8 eV. The dielectric studies confirm that the dielectric constant of TiO{sub 2} increases after doping, however it becomes more conductive. Newly designed S-doped TiO{sub 2} photocatalysts exhibited excellent photocatalytic performance for the degradation of methylene blue (MB) under visible light. The overall photocatalytic activity of 0.11 at.% S-doped TiO{sub 2} was significantly 3-times higher than that of commercial TiO{sub 2} P-25 and complete degradation of MB has taken place after 90 min of irradiation under visible light while only 35% dye degraded when the reaction has been carried out in the presence of undoped TiO{sub 2}.

  9. Metallic glass alloys of Zr, Ti, Cu and Ni

    DOE Patents [OSTI]

    Lin, X.; Peker, A.; Johnson, W.L.

    1997-04-08

    At least quaternary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10{sup 3} K/s. Such alloys comprise titanium from 19 to 41 atomic percent, an early transition metal (ETM) from 4 to 21 atomic percent and copper plus a late transition metal (LTM) from 49 to 64 atomic percent. The ETM comprises zirconium and/or hafnium. The LTM comprises cobalt and/or nickel. The composition is further constrained such that the product of the copper plus LTM times the atomic proportion of LTM relative to the copper is from 2 to 14. The atomic percentage of ETM is less than 10 when the atomic percentage of titanium is as high as 41, and may be as large as 21 when the atomic percentage of titanium is as low as 24. Furthermore, when the total of copper and LTM are low, the amount of LTM present must be further limited. Another group of glass forming alloys has the formula (ETM{sub 1{minus}x}Ti{sub x}){sub a} Cu{sub b} (Ni{sub 1{minus}y}Co{sub y}){sub c} wherein x is from 0.1 to 0.3, y{center_dot}c is from 0 to 18, a is from 47 to 67, b is from 8 to 42, and c is from 4 to 37. This definition of the alloys has additional constraints on the range of copper content, b. 2 figs.

  10. Enhanced photocatalytic activity of TiO{sub 2} nanobarbed fibers treated with atmospheric pressure plasma using O{sub 2} gas

    SciTech Connect (OSTI)

    Lee, Hyun-Uk; Ahn, Kyun; Jeong, Se-Young; Cho, Chae-Ryong; Kim, Jong-Pil; Bae, Jong-Seong; Kim, Hyun-Gyu; Kwon, Se-Hun; Lee, Hyung Woo

    2010-11-29

    TiO{sub 2} nanobarbed fibers (NBFs) were prepared by growing rutile TiO{sub 2} nanorods on anatase TiO{sub 2} nanofibers via electrospinning and hydrothermal reaction processes. There was a large increase in the photocatalytic activity of O{sub 2}-plasma-treated (OP)-TiO{sub 2} NBFs relative to that of the TiO{sub 2} NBFs; this is due to the hydroxylation of the surface of the TiO{sub 2} NBFs by OP treatment. The repeatability of the photocatalytic activity of the OP-TiO{sub 2} NBFs was found to be high and the decolorization rate after ten cycles was 88.3% of the initial value. These results indicate that OP-TiO{sub 2} NBFs have great potential for use as a photocatalyst.

  11. Evolution of structure in Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} single...

    Office of Scientific and Technical Information (OSTI)

    Evolution of structure in Nasub 0.5Bisub 0.5TiOsub 3 single crystals with BaTiOsub 3 Citation Details In-Document Search Title: Evolution of structure in Nasub 0.5Bisub ...

  12. Ab initio study of structural stability and electronic properties of Ti{sub 1-x}Mg{sub x}Cr{sub 2} and TiMg{sub x}Cr{sub 2-x} laves phase

    SciTech Connect (OSTI)

    Sari, A. Merad, G.

    2015-03-30

    The structural stability and electronic properties of TiMgCr{sub 2} laves phase have been calculated and compared. It is found that Mg prefer to substitutes titanium than chromium. The values of entalpies of formation show that Ti{sub 1-x}Mg{sub x}Cr{sub 2} may exist for only one concentration x=0.125 and the more favorable alloy is Ti{sub 0.875}Mg{sub 0.125}Cr{sub 2}. For TiCr{sub 2}, the optimized structural parameters were in good agreement with experimental values, while for TiMgCr{sub 2}, there is not experimental data. The electronic densities of states (DOS) are given and the nature of bonds are also discussed.

  13. Thermoelectricity of Nanocomposites Containing TiO2CoO Coaxial Nanocables

    SciTech Connect (OSTI)

    Su, L.; Zhang, L.; Gana, Y.X.

    2011-04-01

    TiO{sub 2}-CoO coaxial nanocables were deposited into anodic aluminum oxide (AAO) nanoporous templates to form nanocomposite materials. Electron microscopic analysis was conducted to reveal their structures. Seebeck coefficients of the composites were measured. The highest absolute value of Seebeck coefficient is 393 {micro}V K{sup -1} for the TiO{sub 2} nanotube-filled AAO. The TiO{sub 2}-CoO coaxial nanocable-filled AAO has a lower absolute value of 300 {micro}V K{sup -1}. Both composites showed n-type behavior. The effect of Ag nanoparticles addition on the thermoelectric behavior was also examined.

  14. Molecular beam epitaxy of SrTiO{sub 3} with a growth window

    SciTech Connect (OSTI)

    Jalan, Bharat; Moetakef, Pouya; Stemmer, Susanne

    2009-07-20

    Many complex oxides with only nonvolatile constituents do not have a wide growth window in conventional molecular beam epitaxy (MBE) approaches, which makes it difficult to obtain stoichiometric films. Here it is shown that a growth window in which the stoichiometry is self-regulating can be achieved for SrTiO{sub 3} films by using a hybrid MBE approach that uses a volatile metal-organic source for Ti, titanium tetra isopropoxide (TTIP). The growth window widens and shifts to higher TTIP/Sr flux ratios with increasing temperature, showing that it is related to the desorption of the volatile TTIP. We demonstrate stoichiometric, highly perfect, insulating SrTiO{sub 3} films. The approach can be adapted for the growth of other complex oxides that previously were believed to have no wide MBE growth window.

  15. In situ nanoindentation study of plastic Co-deformation in Al-TiN nanocomposites

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, N.; Wang, H.; Misra, A.; Wang, J.

    2014-10-16

    We performed in situ indentation in a transmission electron microscope on Al-TiN multilayers with individual layer thicknesses of 50 nm, 5 nm and 2.7 nm to explore the effect of length scales on the plastic co-deformability of a metal and a ceramic. At 50 nm, plasticity was confined to the Al layers with easy initiation of cracks in the TiN layers. At 5 nm and below, cracking in TiN was suppressed and post mortem measurements indicated a reduction in layer thickness in both layers. Our results demonstrate the profound size effect in enhancing plastic co-deformability in nanoscale metal-ceramic multilayers.

  16. Microstructural evaluation of NiTi-based films deposited by magnetron sputtering

    SciTech Connect (OSTI)

    Crăciunescu, Corneliu M. Mitelea, Ion Budău, Victor; Ercuţa, Aurel

    2014-11-24

    Shape memory alloy films belonging to the NiTi-based systems were deposited on heated and unheated substrates, by magnetron sputtering in a custom made system, and their structure and composition was analyzed using electron microscopy. Several substrates were used for the depositions: glass, Cu-Zn-Al, Cu-Al-Ni and Ti-NiCu shape memory alloy ribbons and kapton. The composition of the Ti-Ni-Cu films showed limited differences, compared to the one of the target and the microstructure for the DC magnetron sputtering revealed crystallized structure with features determined on peel off samples from a Si wafer. Both inter and transcrystalline fractures were observed and related to the interfacial stress developed on cooling from deposition temperature.

  17. Dielectric response of metal/SrTiO{sub 3}/two-dimensional electron liquid heterostructures

    SciTech Connect (OSTI)

    Mikheev, Evgeny; Raghavan, Santosh; Stemmer, Susanne

    2015-08-17

    Maximizing the effective dielectric constant of the gate dielectric stack is important for electrostatically controlling high carrier densities inherent to strongly correlated materials. SrTiO{sub 3} is uniquely suited for this purpose, given its extremely high dielectric constant, which can reach 10{sup 4}. Here, we present a systematic study of the thickness dependence of the dielectric response and leakage of SrTiO{sub 3} that is incorporated into a vertical structure on a high-carrier-density two-dimensional electron liquid (2DEL). A simple model can be used to interpret the data. The results show a need for improved interface control in the design of metal/SrTiO{sub 3}/2DEL devices.

  18. Microstructure evolution in solution treated Ti15Mo alloy processed by high pressure torsion

    SciTech Connect (OSTI)

    Jane?ek, Milo; ?ek, Jakub; Strsk, Josef; Vclavov, Kristna; Hruka, Petr; Polyakova, Veronika; Gatina, Svetlana; Semenova, Irina

    2014-12-15

    Microstructure evolution and mechanical properties of ultra-fine grained Ti15Mo alloy processed by high pressure torsion were investigated. High pressure torsion straining resulted in strong grain refinement as-observed by transmission electron microscopy. Microhardness and light microscopy showed two distinct regions (i) a central region with radial material flow and low microhardness (340 HV) and (ii) a peripheral region with rotational material flow and high microhardness (430 HV). Positron annihilation spectroscopy showed that the only detectable defects in the material are dislocations, whose density increases with the radial distance and the number of high pressure torsion revolutions. The local chemical environment around defects does not differ significantly from the average composition. - Highlights: Beta-Ti alloy Ti15Mo was processed by high pressure torsion (HPT). Lateral inhomogeneity of the microstructure and microhardness was found. Dislocations are the only lattice defects detectable by positron annihilation. Molybdenum is not preferentially segregated along dislocation cores.

  19. Industrial Application of Thin Films (TiAl)N Deposited on Thermo-Wells

    SciTech Connect (OSTI)

    Velez, G.; Jaramillo, S.; Arango, Y. C.; Devia, D.; Quintero, J.; Devia, A.

    2006-12-04

    The thermo-well is formed by two layers, one layer is a ceramic and the other layer is anviloy (comprised tungsten). They are used to coat the thermocouple in the control temperature system during the Aluminum-Silicon alloy melting process. After two weeks of continuous work at 750 deg. C of temperature (the alloy temperature), a high wear in this material is observed, affecting the ceramic. (TiAl)N thin films are deposited directly on the anviloy substrates by the PAPVD (Plasma Assisted Physics Vapor Deposition) in arc pulsed technique, using a TiAl target in a mono-vaporizer system, composed by a reactor and a power controlled system. Two opposite electrodes are placed into the reactor and discharge is produced by a controlled power system. The XRD (X-ray diffraction) patterns show the presence of the (TiAl)N thin film peaks. The morphological characteristics are studied by the scanning probe microscopy (SPM)

  20. Diffusion anisotropy of poor metal solute atoms in hcp-Ti

    SciTech Connect (OSTI)

    Scotti, Lucia Mottura, Alessandro

    2015-05-28

    Atom migration mechanisms influence a wide range of phenomena: solidification kinetics, phase equilibria, oxidation kinetics, precipitation of phases, and high-temperature deformation. In particular, solute diffusion mechanisms in α-Ti alloys can help explain their excellent high-temperature behaviour. The purpose of this work is to study self- and solute diffusion in hexagonal close-packed (hcp)-Ti, and its anisotropy, from first-principles using the 8-frequency model. The calculated diffusion coefficients show that diffusion energy barriers depend more on bonding characteristics of the solute rather than the size misfit with the host, while the extreme diffusion anisotropy of some solute elements in hcp-Ti is a result of the bond angle distortion.