National Library of Energy BETA

Sample records for transportation dot research

  1. DOT Awards University Transportation Centers $63 Million | Department of

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

    Energy DOT Awards University Transportation Centers $63 Million DOT Awards University Transportation Centers $63 Million October 23, 2013 - 12:00am Addthis The U.S. Department of Transportation’s (DOT) on September 26 announced approximately $63 million in grants to 33 University Transportation Centers to advance research and education programs that address critical transportation challenges. The selected universities will research a wide range of transportation-related issues

  2. Transportation Research

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

    transportation-research TRACC RESEARCH Computational Fluid Dynamics Computational Structural Mechanics Transportation Systems Modeling Transportation Research Current Research Overview The U.S. Department of Transportation (USDOT) has established its only high-performance computing and engineering analysis research facility at Argonne National Laboratory to provide applications support in key areas of applied research and development for the USDOT community. The Transportation Research and

  3. Nontoxic quantum dot research improves solar cells

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

    Nontoxic quantum dot research improves solar cells Nontoxic quantum dot research improves solar cells Solar cells made with low-cost, nontoxic copper-based quantum dots can achieve unprecedented longevity and efficiency, according to a study by LANL and Sharp Corporation. December 10, 2013 Hunter McDaniel, Los Alamos National Laboratory postdoctoral researcher, works in the laboratory developing next-generation quantum dots that could revolutionize photovoltaic technology. Hunter McDaniel, Los

  4. Sandia Energy - Research Challenge 2: Quantum Dots and Phosphors

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

    2: Quantum Dots and Phosphors Home Energy Research EFRCs Solid-State Lighting Science EFRC Our SSLS EFRC's Scientific Research Challenges and Publications Research Challenge 2:...

  5. Nontoxic quantum dot research improves solar cells

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

    reported for any quantum dot solar cell," said Hunter McDaniel. Record power-conversion efficiency at Los Alamos from quantum-dot sensitized photovoltaics LOS ALAMOS, N.M., Dec....

  6. Los Alamos researchers unravel the mystery of quantum dot blinking

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

    Researchers unravel the mystery of quantum dot blinking Los Alamos researchers unravel the mystery of quantum dot blinking Most exciting is that the Los Alamos researchers have shown that blinking can be controlled and even completely suppressed electrochemically. November 9, 2011 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy

  7. NREL: Transportation Research - Webmaster

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

    Webmaster Please enter your name and email address in the boxes provided, then type your message below. When you are finished, click "Send Message." NOTE: If you enter your e-mail address incorrectly, we will be unable to reply. Your name: Your email address: Your message: Send Message Printable Version Transportation Research Home Capabilities Projects

  8. Research Challenge 2: Quantum Dots and Phosphors

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

    2: Quantum Dots and Phosphors - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs

  9. NREL: Transportation Research - Sustainable Transportation Basics

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

    an introduction to sustainable transportation. NREL research supports development of electric, hybrid, hydrogen fuel cell, biofuel, natural gas, and propane vehicle technologies. ...

  10. The impact of disorder on charge transport in three dimensional quantum dot

    Office of Scientific and Technical Information (OSTI)

    resonant tunneling structures (Journal Article) | SciTech Connect The impact of disorder on charge transport in three dimensional quantum dot resonant tunneling structures Citation Details In-Document Search Title: The impact of disorder on charge transport in three dimensional quantum dot resonant tunneling structures Efficient iso-entropic energy filtering of electronic waves can be realized through nanostructures with three dimensional confinement, such as quantum dot resonant tunneling

  11. NREL: Transportation Research - News

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

    work on fuel cell electric vehicle technologies. Transportation and Hydrogen Newsletter Stay up to date on NREL's RD&D of transportation and hydrogen technologies with this...

  12. NREL: Transportation Research - Transportation and Hydrogen Newsletter

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

    Transportation and Hydrogen Newsletter The Transportation and Hydrogen Newsletter is a monthly electronic newsletter that provides information on NREL's research, development, and deployment of transportation and hydrogen technologies. Photo of a stack of newspapers January 2016 Issue Sustainable Mobility Read the latest issue of the newsletter. Subscribe: To receive new issues by email, subscribe to the newsletter. Archives: For past issues, read the newsletter archives. Printable Version

  13. the-transportation-research-board

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

    January 22-26, 2012 The Transportation Research Board (TRB) 91st Annual Meeting will be held in Washington, D.C. at the Washington Marriott Wardman Park, Omni Shoreham, and Washington Hilton hotels. The information-packed program will attract more than 11,000 transportation professionals from around the world to Washington, D.C., January 22-26, 2012. The Transportation Research and Analysis Computing Center (TRACC) team will showcase current projects at the upcoming Transportation Research Board

  14. NREL: Transportation Research - Capabilities

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

    Capabilities A Vision for Sustainable Transportation Line graph illustrating three pathways (biofuel, hydrogen, and electric vehicle) to reduce energy use and greenhouse gas ...

  15. NREL: Transportation Research - Energy Storage

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

    Energy Storage Transportation Research Cutaway image of an automobile showing the location of energy storage components (battery and inverter), as well as electric motor, power ...

  16. NREL: Transportation Research Home Page

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

    Transportation Research Silver Toyota Prius being driven in front of NREL entrance sign. NREL helps industry partners develop the next generation of energy efficient, high performance vehicles and fuels. Thermal image of two men standing in front of tractor trailer cab. NREL conducts research on the full range of vehicle types, from light-duty passenger cars to heavy-duty freight trucks. Female researcher holding coin cell battery. NREL's transportation research spans from the materials to the

  17. NREL: Transportation Research - Projects

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

    Projects 3-D illustration of tractor trailor cab, garbage truck, and car. NREL research helps optimize the energy efficiency of a wide range of vehicle technologies and...

  18. Transport Research Laboratory | Open Energy Information

    Open Energy Info (EERE)

    Research Laboratory Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Transport Research Laboratory AgencyCompany Organization: Transport Research Laboratory Focus Area:...

  19. Exciton dissociation and interdot transport in CdSe quantum-dot molecules

    SciTech Connect (OSTI)

    Franceschetti, Alberto; Zunger, Alex

    2001-04-15

    One of the most important parameters that determine the transport properties of a quantum dot array is the exciton dissociation energy, i.e., the energy {Delta}E required to dissociate an exciton into an electron and a hole localized in different dots. We show that a pseudopotential calculation for a dot molecule, coupled with a basic configuration interaction calculation of the exciton energy levels, provides directly the exciton dissociation energy, including the effects of wave function overlap, screened Coulomb attraction between the electron and the hole in different dots, and polarization effects. We find that {Delta}E decreases as the interdot distance decreases and as the dielectric constant of the medium increases.

  20. Cornell dots research collaboration leads to $10M cancer center...

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

    at MSKCC in New York City - will focus on melanoma (skin) and malignant brain cancers. ... Assessment of particles in brain tumors for cancer therapy. C dots successfully have ...

  1. Cornell dots research collaboration leads to $10M cancer center > EMC2 News

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

    > The Energy Materials Center at Cornell dots research collaboration leads to $10M cancer center September 24th, 2015 › Provided/Wiesner Lab A rendering of the molecular structure of a Cornell dot, which is smaller than 10 nanometers. Provided/Wiesner Lab A transmission electron microscope image of Cornell dots. C dots, which are injected into patients, are designed to either adhere to and light up cancer cells or quickly leave the body. Cornell University, in partnership with Memorial

  2. New Transportation Technology | GE Global Research

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

    transportation solutions. Home > Innovation > Transportation A World-Class Traction Motor for Hybrid and Electric Vehicles Engineers at GE Global Research are advancing motor...

  3. The impact of disorder on charge transport in three dimensional quantum dot resonant tunneling structures

    SciTech Connect (OSTI)

    Puthen-Veettil, B. Patterson, R.; Knig, D.; Conibeer, G.; Green, M. A.

    2014-10-28

    Efficient iso-entropic energy filtering of electronic waves can be realized through nanostructures with three dimensional confinement, such as quantum dot resonant tunneling structures. Large-area deployment of such structures is useful for energy selective contacts but such configuration is susceptible to structural disorders. In this work, the transport properties of quantum-dot-based wide-area resonant tunneling structures, subject to realistic disorder mechanisms, are studied. Positional variations of the quantum dots are shown to reduce the resonant transmission peaks while size variations in the device are shown to reduce as well as broaden the peaks. Increased quantum dot size distribution also results in a peak shift to lower energy which is attributed to large dots dominating transmission. A decrease in barrier thickness reduces the relative peak height while the overall transmission increases dramatically due to lower series resistance. While any shift away from ideality can be intuitively expected to reduce the resonance peak, quantification allows better understanding of the tolerances required for fabricating structures based on resonant tunneling phenomena/.

  4. NREL: Transportation Research - Transportation Deployment Support

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

    Transportation Deployment Support Photo of a car parked in front of a monument. A plug-in electric vehicle charges near the Thomas Jefferson Memorial in Washington, D.C. Photo from...

  5. NREL: Transportation Research - Transportation and Hydrogen Newsletter...

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

    Energy Storage This is the November 2015 issue of the Transportation and Hydrogen Newsletter. November 6, 2015 Photo of a light blue car with a pump nozzle in front of a fuel ...

  6. NREL: Transportation Research - Transportation and Hydrogen Newsletter:

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

    Hydrogen and Fuel Cell Technology Hydrogen and Fuel Cell Technology This is the May 2015 issue of the Transportation and Hydrogen Newsletter. May 28, 2015 Photo of a car refueling at a hydrogen dispensing station. DOE's H2FIRST project focuses on accelerating the acceptance of hydrogen infrastructure. Photo by John De La Rosa, NREL 33660 New H2FIRST Reports Detail Hydrogen Station Designs, Contaminant Detection Two new reports have been published by NREL and Sandia National Laboratories

  7. NREL: Transportation Research - Transportation and Hydrogen Newsletter:

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

    Sustainable Mobility Sustainable Mobility This is the January 2016 issue of the Transportation and Hydrogen Newsletter. January 26, 2016 Photo of a red electric vehicle in front of ESIF A recent mobility workshop showcased an array of plug-in electric, hybrid electric, and hydrogen fuel cell vehicles. Image by Ellen Jaskol/NREL 35097 Summit Explores the Future of Dynamic Mobility Systems NREL brought together local and national thought leaders to discuss the convergence of connectivity,

  8. Charge transport and memristive properties of graphene quantum dots embedded in poly(3-hexylthiophene) matrix

    SciTech Connect (OSTI)

    Cosmin Obreja, Alexandru; Cristea, Dana; Radoi, Antonio; Gavrila, Raluca; Comanescu, Florin; Kusko, Cristian; Mihalache, Iuliana

    2014-08-25

    We show that graphene quantum dots (GQD) embedded in a semiconducting poly(3-hexylthiophene) polymeric matrix act as charge trapping nanomaterials. In plane current-voltage (I-V) measurements of thin films realized from this nanocomposite deposited on gold interdigitated electrodes revealed that the GQD enhanced dramatically the hole transport. I-V characteristics exhibited a strong nonlinear behavior and a pinched hysteresis loop, a signature of a memristive response. The transport properties of this nanocomposite were explained in terms of a trap controlled space charge limited current mechanism.

  9. Elastic tunneling charge transport mechanisms in silicon quantum dots /SiO{sub 2} thin films and superlattices

    SciTech Connect (OSTI)

    Illera, S. Prades, J. D.; Cirera, A.

    2015-05-07

    The role of different charge transport mechanisms in Si/SiO{sub 2} structures has been studied. A theoretical model based on the Transfer Hamiltonian Formalism has been developed to explain experimental current trends in terms of three different elastic tunneling processes: (1) trap assisted tunneling; (2) transport through an intermediate quantum dot; and (3) direct tunneling between leads. In general, at low fields carrier transport is dominated by the quantum dots whereas, for moderate and high fields, transport through deep traps inherent to the SiO{sub 2} is the most relevant process. Besides, current trends in Si/SiO{sub 2} superlattice structure have been properly reproduced.

  10. Center for Transportation Research | Argonne National Laboratory

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

    Center for Transportation Research Argonne's Center for Transportation Research (CTR) provides innovative solutions to challenges involving fuel efficiency, emissions, durability, safety, design and operating efficiency, petroleum dependence, interoperability, compatibility and codes/standards compliance and harmonization. The CTR is home to a well-balanced transportation research program staffed by world-class researchers and engineers, who are well known in the technical community and within

  11. Low-temperature transport in ac-driven quantum dots in the Kondo regime

    SciTech Connect (OSTI)

    Lopez, Rosa; Aguado, Ramon; Platero, Gloria; Tejedor, Carlos

    2001-08-15

    We present a fully nonequilibrium calculation of the low-temperature transport properties of a quantum dot in the Kondo regime when an ac potential is applied to the gate. We solve a time-dependent Anderson model with finite on-site Coulomb interaction. The interaction self-energy is calculated up to second order in perturbation theory in the on-site interaction, in the context of the Keldysh nonequilibrium technique, and the effect of the ac voltage is taken into account exactly for all ranges of ac frequencies and ac intensities. The obtained linear conductance and time-averaged density of states of the quantum dot evolve in a nontrivial way as a function of the ac frequency and ac intensity of the harmonic modulation.

  12. Transportation Research Board 94th Annual Meeting

    Broader source: Energy.gov [DOE]

    The Transportation Research Board 94th Annual Meeting will be held January 11–15, 2015, in Washington, D.C. at the Walter E. Washington Convention Center. The event covers the entire transportation...

  13. NREL: Transportation Research - E-Roadway Animation

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

    extend the operational range of electric vehicles. Plus, e-roadway power can come from renewable sources. Text version. Printable Version Transportation Research Home...

  14. A commentary on the 1995 DOT/NRC amendments to the U.S. nuclear transportation regulations

    SciTech Connect (OSTI)

    Grella, A.

    1996-07-01

    This article discusses the major revisions (1995 DOT/NRC ammendments) to the US Nuclear Transportation regulations and their probable impacts on transportation. Areas covered include the following: the LSA and SCO definitions and packaging; radiation protection programs; mandatory use of SI units; changes an additions to the table of A1/A2 radionuclide values; and additional type B package hypothetical accident parameters.

  15. NREL: Transportation Research - Subscribe to the Transportation and

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

    Hydrogen Newsletter Subscribe to the Transportation and Hydrogen Newsletter To subscribe to or unsubscribe from the Transportation and Hydrogen Newsletter, complete one of the forms below. Subscribe To subscribe to the newsletter, submit your email address. Email: Submit Unsubscribe To unsubscribe from the newsletter, submit your email address. Email: Submit Printable Version Transportation Research Home Capabilities Projects Success Stories Facilities Working with Us Publications Data &

  16. NREL: Transportation Research - Fuel Chemistry Research

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

    Chemistry Research Photo of a hand holding a beaker containing a clear yellow liquid. NREL evaluates a broad range of renewable gasoline and diesel fuels-ranging from currently available ethanol and biodiesel to future products such as dimethyl furan and hydrotreated biomass pyrolysis oils. Photo by Dennis Schroeder, NREL NREL's fuel chemistry research explores how biofuels, advanced petroleum-based fuels, fuel blends, and natural gas perform in vehicles as well as in fuel pumps, storage tanks,

  17. NREL: Transportation Research - A Vision for Sustainable Transportation

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

    A Vision for Sustainable Transportation NREL research, development, and deployment accelerates the process of bringing sustainable transportation technologies to market. Line graph illustrating three pathways to reduce transportation energy use and greenhouse gas (GHG) emissions, with "energy consumption of vehicles" along the y-axis (ranging from 0 to 2.0 kWh/km) and "carbon intensity of energy source" along the x-axis (ranging from 450 to 0 g CO2/kWh). A solid bottom line

  18. Kondo-type transport through a quantum dot under magnetic fields

    SciTech Connect (OSTI)

    Dong, Bing; Lei, X. L.

    2001-06-15

    In this paper, we investigate the Kondo correlation effects on linear and nonlinear transport in a quantum dot connected to reservoirs under finite magnetic fields, using the slave-boson mean field approach suggested by Kotliar and Ruckenstein [Phys. Rev. Lett. >57, 1362 (1986)]. A brief comparison between the present formulation and other slave-boson formulation is presented to justify this approach. The numerical results show that the linear conductance near electron-hole symmetry is suppressed by the application of the magnetic fields, but an anomalous enhancement is predicted in the nonsymmetry regime. The effect of external magnetic fields on the nonlinear differential conductances is discussed for the Kondo system. A significant reduction of the peak splitting is observed due to the strong Kondo correlation, which agrees well with experimental data.

  19. Transportation Secure Data Center: Real-World Data for Value Pricing and Tolling Research (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-01-01

    The National Renewable Energy Laboratory (NREL) and the U.S. Department of Transportation (DOT) have launched the free, web-based Transportation Secure Data Center (TSDC). The TSDC (www.nrel.gov/tsdc) preserves respondent anonymity while making vital transportation data available to a broad group of users through secure, online access. The TSDC database provides free-of-charge web-based access to valuable transportation data that can be used for: Location and time-of-day variable tolling research, Mileage-based fee analysis, Travel demand modeling and transit planning, Congestion mitigation research, and Validating transportation data from other sources. The TSDC's two levels of access make composite data available with simple online registration, and allow researchers to use detailed spatial data after completing a straight forward application process.

  20. 1995 revisions to the DOT/NRC transport regulations and their impact on nuclear power plants

    SciTech Connect (OSTI)

    Grella, A.W.

    1996-10-01

    On September 28, 1995, the U.S. Department of Transportation (DOT) and the U.S. Nuclear Regulatory Commission (NRC) published major amendments to the nuclear transportation regulations of the US. The amendments culminated an approximate 8-year effort of the two agencies to conform US regulations (to the extent practicable) to the international transport standards of the International Atomic Energy Agency (IAEA) Safety Series N. 6, {open_quotes}Regulations For The Safe Transport of Radioactive Material{close_quotes}, 1985 Edition (Revised 1990). This paper identifies the major revisions to the regulations which have taken place and discusses not only their probable future impacts but also identifies certain issues and early impacts which have been emerging since publication of the final rules late in 1995. The discussion is summarized with respect to these impacts and issues on transportation of radioactive material by the nuclear power industry. Many of the revisions which are more minor in nature are also identified. The generic effective date for mandatory compliance with the revised regulations was April 1, 1996, however two of the major revisions of interest to the utilities have later effective dates for mandatory compliance. The use of the so-called {open_quotes}NRC-Certified Type A LSA Packages{close_quotes} are authorized until April 1, 1999 and mandatory compliance with the new radiation protection program requirements of 49 CFR 172 Subpart I is not until October 1, 1997. This paper is based to a large extent on the EPRI report bearing the same title as this paper, which is currently in draft.

  1. NREL: Transportation Research - Working with Us

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

    Working with Us Partnerships Drive Transportation Solutions Photo of two men standing in front of a large solar panel and an electric vehicle. NREL offers industry, academia, and other government agencies opportunities to work with us and leverage our research expertise. There are several ways for your organization to get involved with us: Partner with NREL through a Cooperative Research and Development Agreement or a Work-for-Others Agreement. License NREL-developed technologies. The Energy

  2. Sandia Energy - 'Giant' Nanocrystal Quantum Dots

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

    'Giant' Nanocrystal Quantum Dots Home Energy Research EFRCs Solid-State Lighting Science EFRC 'Giant' Nanocrystal Quantum Dots 'Giant' Nanocrystal Quantum DotsTara...

  3. Cost-effectiveness analysis of TxDOT LPG fleet conversion. Volume 1. Interim research report

    SciTech Connect (OSTI)

    Euritt, M.A.; Taylor, D.B.; Mahmassani, H.

    1992-10-01

    Increased emphasis on energy efficiency and air quality has resulted in a number of state and federal initiatives examining the use of alternative fuels for motor vehicles. Texas' program for alternate fuels includes liquefied petroleum gas (LPG). Based on an analysis of 30-year life-cycle costs, development of a propane vehicle program for the Texas Department of Transportation (TxDOT) would cost about $24.3 million (in 1991 dollars). These costs include savings from lower-priced LPG and differentials between propane and gasoline/diesel in infrastructure costs for a fueling station, vehicle costs, and operating costs. The 30-year life-cycle costs translate into an average annual vehicle cost increase of $308, or about 2.5 cents more per vehicle mile of travel. Sensitivity analyses are performed on the discount rate, price of propane, maintenance savings, vehicle utilization, diesel vehicles, extended vehicle life, original equipment manufacturer (OEM) vehicles, and operating and infrastructure costs. The best results are obtained when not converting diesel vehicles, converting only large fleets, and extending the period the vehicle is kept in service. Combining these factors yields results that are most cost-effective for TxDOT. This is volume one of two volumes.

  4. Cost-effectiveness analysis of TxDOT LPG fleet conversion. Volume 2. Interim research report

    SciTech Connect (OSTI)

    Euritt, M.A.; Taylor, D.B.; Mahmassani, H.

    1992-11-01

    Increased emphasis on energy efficiency and air quality has resulted in a number of state and federal initiatives examining the use of alternative fuels for motor vehicles. Texas' program for alternate fuels includes liquefied petroleum gas (LPG), commonly called propane. Based on an analysis of 30-year life-cycle costs, development of a propane vehicle program for the Texas Department of Transportation (TxDOT) would cost about $24.3 million (in 1991 dollars). These costs include savings from lower-priced propane and differentials between propane and gasoline/diesel in infrastructure costs, vehicle costs, and operating costs. The 30-year life-cycle costs translate into an average annual vehicle cost increase of $308, or about 2.5 cents more per vehicle mile of travel. Based on the cost-effectiveness analysis and assumptions, there are currently no TxDOT locations that can be converted to propane without additional financial outlays. This is volume two of two volumes.

  5. The role of transport processes of nonequilibrium charge carriers in radiative properties of arrays of InAs/GaAs quantum dots

    SciTech Connect (OSTI)

    Shkolnik, A. S. Savelyev, A. V.; Karachinsky, L. Ya.; Gordeev, N. Yu.; Seisyan, R. P.; Zegrya, G. G.; Pellegrini, S.; Buller, G. S.; Evtikhiev, V. P.

    2008-03-15

    The results of time-resolved photoluminescence studies of heterostructures containing monolayer arrays of InAs/GaAs quantum dots are presented. A two-component time dependence of intensity of photoluminescence from the ground state of quantum dots, with characteristic times of the slow component up to hundreds of nanoseconds and those of rapid one several nanoseconds, is studied. It is shown that the slow component is determined by the transport of nonequilibrium charge carriers between the quantum dots. At low temperatures, the time of the slow component is determined by tunneling, and at high temperatures by thermal escape of nonequilibrium charge carriers. The ratio of the contributions of tunneling and thermal escape is determined by the degree of isolation of quantum dots. A theoretical model is constructed that describes the effect of the dynamics of carrier transport on the emergence and decay of the slow component of photoluminescence.

  6. Promising future of quantum dots explored in conference

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

    Promising future of quantum dots explored Promising future of quantum dots explored in conference Researchers are gathering to reflect on two decades of quantum dot research at a...

  7. UC Berkeley-Transportation Sustainability Research Center | Open...

    Open Energy Info (EERE)

    Sustainability Research Center Jump to: navigation, search Name: UC Berkeley-Transportation Sustainability Research Center Address: 2614 Dwight Way Place: Berkeley, California Zip:...

  8. NREL: Transportation Research - Archives for the Transportation and

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

    Hydrogen Newsletter Archives for the Transportation and Hydrogen Newsletter To read past issues of the Transportation and Hydrogen Newsletter, select from the list below. January 2016 - Sustainable Mobility November 2015 - Energy Storage August 2015 - Deployment May 2015 - Hydrogen & Fuel Cell Technology March 2015 - Fuels and Combustion January 2015 - The Future of Sustainable Transportation December 2014 - Marketplace Impact October 2014 - Reliability, Durability, and Safety July 2014

  9. NREL Researchers Demonstrate External Quantum Efficiency Surpassing 100% in a Quantum Dot Solar Cell (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-12-01

    A new device that produces and collects multiple electrons per photon could yield inexpensive, high-efficiency photovoltaics. A new device developed through research at the National Renewable Energy Laboratory (NREL) reduces conventional losses in photovoltaic (PV) solar cells, potentially increasing the power conversion efficiency-but not the cost-of the solar cells. Solar cells convert optical energy from the sun into usable electricity; however, almost 50% of the incident energy is lost as heat with present-day technologies. High-efficiency, multi-junction cells reduce this heat loss, but their cost is significantly higher. NREL's new device uses excess energy in solar photons to create extra charges rather than heat. This was achieved using 5-nanometer-diameter quantum dots of lead selenide (PbSe) tightly packed into a film. The researchers chemically treated the film, and then fabricated a device that yielded an external quantum efficiency (number of electrons produced per incident photon) exceeding 100%, a value beyond that of all current solar cells for any incident photon. Quantum dots are known to efficiently generate multiple excitons (a bound electron-hole pair) per absorbed high-energy photon, and this device definitively demonstrates the collection of multiple electrons per photon in a PV cell. The internal quantum efficiency corrects for photons that are not absorbed in the photoactive layer and shows that the PbSe film generates 30% to 40% more electrons in the high-energy spectral region than is possible with a conventional solar cell. While the unoptimized overall power conversion efficiency is still low (less than 5%), the results have important implications for PV because such high quantum efficiency can lead to more electrical current produced than possible using present technologies. Furthermore, this fabrication is also amenable to inexpensive, high-throughput roll-to-roll manufacturing.

  10. NREL: Transportation Research - Vehicle Thermal Management

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

    transported across the United States each year. Idling these vehicles to heat and cool cabsleeper spaces improves driver comfort and safety, but consumes large quantities of...

  11. NREL: Transportation Research - News Release Archives

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

    2 December 28, 2012 Clean Cities YouTube Channel Offers Videos on Alternative Fuels and Advanced Vehicles The NREL-developed Clean Cities YouTube channel offers informative videos that can help vehicle fleet managers and transportation decision makers reduce petroleum use by gleaning insight from a variety of alternative transportation topics. December 21, 2012 NREL Names New Executive The U.S. Department of Energy's National Renewable Energy Laboratory today named Barbara Goodman as Associate

  12. Fuel Cells for Transportation - Research and Development: Program...

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

    Research and Development: Program Abstracts Fuel Cells for Transportation - Research and ... The potential markets are huge, but so are the R&D risks. Given the potential for PEM fuel ...

  13. Transport properties and Kondo correlations in nanostructures: Time-dependent DMRG method applied to quantum dots coupled to Wilson chains

    SciTech Connect (OSTI)

    Dias Da Silva, Luis G; Heidrich-Meisner, Fabian; Feiguin, Adrian E; Busser, C. A.; Martins, G. B.; Anda, E. V.; Dagotto, Elbio R

    2008-01-01

    We apply the adaptive time-dependent density-matrix renormalization-group method tDMRG to the study of transport properties of quantum-dot systems connected to metallic leads. Finite-size effects make the usual tDMRG description of the Kondo regime a numerically demanding task. We show that such effects can be attenuated by describing the leads by Wilson chains, in which the hopping matrix elements decay exponentially away from the impurity tn n/2. For a given system size and in the linear-response regime, results for 1 show several improvements over the undamped =1 case: perfect conductance is obtained deeper in the strongly interacting regime and current plateaus remain well defined for longer time scales. Similar improvements were obtained in the finite-bias regime up to bias voltages of the order of the Kondo temperature. These results show that with the proposed modification, the tDMRG characterization of Kondo correlations in the transport properties can be substantially improved, while it turns out to be sufficient to work with much smaller system sizes. We discuss the numerical cost of this approach with respect to the necessary system sizes and the entanglement growth during the time evolution.

  14. NREL: Transportation Research - News Release Archives

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

    5 December 16, 2015 Helping Electric-Drive Vehicle Power Electronics Keep Their Cool Conventional thermal interface materials can pose a significant bottleneck to heat removal from power electronics packages. High-performance thermal interface materials are a critical enabler to compact, high-performance, low-cost power electronics components for transportation and other applications. November 17, 2015 NREL Efforts Push Hydrogen Vehicles Further Along New fast-filling fuel station dedicated as

  15. NREL: Transportation Research - Truck Stop Electrification Testing

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

    Truck Stop Electrification Testing Photo of series of truck stop electrification pedestals near highway with heavy-duty truck parked in the background. NREL is monitoring the use of truck stop electrification sites across the nation. Photo courtesy of Shorepower Technologies NREL's fleet test and evaluation team is evaluating and documenting the use of 50 truck stop electrification (TSE) sites along the busiest transportation corridors in the United States. Truck drivers typically idle their

  16. Center for Transportation Research | Argonne National Laboratory

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

    Advanced Vehicle Technologies Friction, Wear, and Lubrication Technologies Fuel Spray Analysis Multi-Dimensional Modeling Vehicle-Grid Interoperability CTR research occurs in...

  17. NREL: Transportation Research - Electric Motor Thermal Management

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

    Electric Motor Thermal Management A photo of a piece of laboratory testing equipment. NREL research in electric motors is helping to improve the performance and reliability of electric-drive vehicles. Photo by Kevin Bennion, NREL NREL's electric motor thermal management research generates experimental data and simulation processes for the modeling, analysis, design, and construction of new electric motors. Electric motor thermal management involves a multifaceted interaction of motor operating

  18. NREL: Transportation Research - News Release Archives

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

    4 November 20, 2014 Innovative Way to Test Batteries Fills a Market Niche Isothermal Battery Calorimeters (IBCs), developed by NREL researchers, are capable of performing the precise thermal measurements needed to make safer, longer-lasting, and more cost-effective batteries for in a variety of applications. November 12, 2014 Webinar November 18: An Overview of the Hydrogen Fueling Infrastructure Research and Station Technology (H2FIRST) Project Led by the National Renewable Energy Laboratory

  19. Research in transportation: the shape of the future

    SciTech Connect (OSTI)

    Chenea, P.F.

    1981-01-01

    The individual mobility now enjoyed due to advancements in the transportation sector is being threatened by higher fuel costs and declining petroleum resources. Transportation research approaches must address these problems. Automotive engineers must redesign existing vehicles to make them smaller, lighter, and so more fuel efficient. Alternatives to the gasoline engine, such as gas turbine and stratified charge engines, must be commercialized.

  20. Vehicle Technologies Office: Data and Analysis for Transportation Research

    Broader source: Energy.gov [DOE]

    The U.S. Department of Energy (DOE) — in conjunction with the national laboratories — conducts a wide range of statistical research on energy use, economics, and trends in transportation.

  1. NREL: Transportation Research - Power Electronics Packaging Reliability

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

    Packaging Reliability A photo of a piece of power electronics testing equipment. NREL power electronics packaging reliability research investigates the performance and reliability of emerging interconnection, interface, and packaging materials. Findings help improve reliability and durability of emerging technologies. Photo by Dennis Schroeder, NREL Power electronics packaging around a semiconductor switching device determines the electrical, thermal, and mechanical properties of a power

  2. Fuel Cells for Transportation - Research and Development: Program Abstracts

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

    | Department of Energy Research and Development: Program Abstracts Fuel Cells for Transportation - Research and Development: Program Abstracts Remarkable progress has been achieved in the development of proton-exchange-membrane(PEM) fuel cell technology since the U.S. Department of Energy (DOE) initiated a significant developmental program in the early 1990s. This progress has stimulated enormous interest worldwide in developing fuel cell products for transportation as well as for stationary

  3. NREL: Transportation Research - Alternative Fuels Characterization

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

    Alternative Fuels Characterization Find out about other biomass research projects at NREL. NREL alternative fuels projects help overcome technical barriers and expand markets for renewable, biodegradable vehicle fuels. These liquid fuels include higher-level ethanol blends, butanol, biodiesel, renewable diesel, other biomass-derived fuels, and natural gas. By studying the fuel chemistry as well as combustion and emissions impacts of alternative fuels, NREL helps improve engine efficiency, reduce

  4. NREL: Transportation Research - News Release Archives

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

    0 December 28, 2010 NREL Helps Corporate Fleets Go Green Researchers work with companies to evaluate the latest technology commercially available in the medium and heavy-duty truck markets. December 14, 2010 Hydrogen Bus Lets Lab Visitors Glimpse Future The hydrogen bus uses the same basic technology as a conventional gasoline-powered engine but runs on renewable hydrogen. October 18, 2010 NREL's Hydrogen-Powered Bus Serves as Showcase for Advanced Vehicle Technologies NREL uses its

  5. NREL: Transportation Research - News Release Archives

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

    3 December 23, 2013 NREL and Thought Leaders Gather at Electric Vehicle Battery Management Summit NREL researchers will gather with U.S. Department of Energy program directors and technology managers, and other thought leaders to exchange strategies for maximizing the performance, safety, and lifespan of electric-drive vehicle batteries. November 7, 2013 NREL Developed Mobile App for Alternative Fueling Station Locations Released iPhone users now have access to a free application that locates

  6. NREL: Transportation Research - Power Electronics Thermal Management

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

    Power Electronics Thermal Management A photo of water boiling in liquid cooling lab equipment. Power electronics thermal management research aims to help lower the cost and improve the performance of electric-drive vehicles. Photo by Dennis Schroeder, NREL NREL investigates and develops thermal management strategies for power electronics systems that use wide-bandgap technology, which enables the development of devices that are smaller than those based on other materials, demonstrating

  7. NREL: Transportation Research - Thermal Performance Benchmarking

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

    Thermal Performance Benchmarking A photo of the internal components of an automotive inverter. NREL thermal performance benchmarking of state-of-the-art power electronics and electric motors helps guide future R&D efforts as well as industry product-development efforts. Photo by Scot Waye, NREL NREL's thermal performance benchmarking research focuses on state-of-the-art technologies used in electric-drive vehicle (EDV) systems. Benchmarks are shared with industry so that systems can be

  8. NREL: Transportation Research - Vehicle Thermal Management Facilities

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

    Vehicle Thermal Management Facilities Image of a building with two semi truck cabs in front of it. The VTIF is used for thermal testing of every class of on-road vehicle. Photo by Dennis Schroeder, NREL The National Renewable Energy Laboratory (NREL) uses research and testing facilities to develop advanced thermal management technologies for vehicles. Vehicle Testing and Integration Facility The Vehicle Testing and Integration Facility features a test pad to conduct vehicle thermal soak testing

  9. Sandia Energy - Expansion of DOE-DOT Tight Oil Research Work

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

    of tight crude oils as they relate to potential combustion events in the rail transport environment. Key objectives of this investigation are to characterize and define tight...

  10. NREL: Transportation Research - Driverless Cars and Fuel Efficiency

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

    Spotlighted in Scientific American Driverless Cars and Fuel Efficiency Spotlighted in Scientific American January 25, 2016 The potential to slow pollution through deployment of automated vehicles is gaining more and more traction in the news. In a recent Scientific American article, reporter Camille von Kaenel asked NREL's Jeff Gonder for a transportation researcher's thoughts on both the sustainability benefits and uncertainties that will accompany an increase in driverless cars. "The

  11. NREL: Transportation Research - E-Roadway Animation (Text Version)

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

    Transportation Research Printable Version E-Roadway Animation (Text Version) This text version of the e-roadway animation describes how electrified roadways can reduce petroleum consumption and vehicle operating costs while extending the range of electric vehicles. Part One: E-Roadway Introduction and Benefits Reducing emissions and oil consumption are crucial worldwide goals. Many technologies can contribute to achieving these goals-efficient homes, biofuels, hybrid electric vehicles, hydrogen

  12. Promising future of quantum dots explored in conference

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

    Promising future of quantum dots explored Promising future of quantum dots explored in conference Researchers are gathering to reflect on two decades of quantum dot research at a special topical conference, "20 Years of Quantum Dots at Los Alamos" April 13, 2015 Quantum dot LSC devices under ultraviolet illumination. Quantum dot LSC devices under ultraviolet illumination. Contact Los Alamos National Laboratory Nancy Ambrosiano Communications Office (505) 667-0471 Email "This

  13. DOT specification packages evaluation

    SciTech Connect (OSTI)

    Ratledge, J.E.; Rawl, R.R. )

    1991-01-01

    During the late 1960s and early 1970s, the Department of Transportation (DOT) specification package system was implemented to serve as a useful and equivalent alternative to the Nuclear Regulatory Commission (NRC) and the Bureau of Explosives approval systems for Type B and fissile radioactive material package designs. When a package design was used by a large number of organizations, the package design was added to the DOT regulations as a specification package authorized for use by any shipper. In the mid-1970s, the NRC revised its package design certification system to the one in use today. This paper reports that, while the NRC and DOT transportation regulations have evolved over the years, the DOT specification package designs have remained largely unchanged. Questions have been raised as to whether these designs meet the current and proposed regulations. In order to enable the NRC and DOT to develop a regulatory analysis that will support appropriate action regarding the specification packages, a study is being performed to compile all available design, testing, and analysis information on these packages.

  14. Transportable Heavy Duty Emissions Testing Laboratory and Research Program

    SciTech Connect (OSTI)

    David Lyons

    2008-03-31

    The objective of this program was to quantify the emissions from heavy-duty vehicles operating on alternative fuels or advanced fuel blends, often with novel engine technology or aftertreatment. In the first year of the program West Virginia University (WVU) researchers determined that a transportable chassis dynamometer emissions measurement approach was required so that fleets of trucks and buses did not need to be ferried across the nation to a fixed facility. A Transportable Heavy-Duty Vehicle Emissions Testing Laboratory (Translab) was designed, constructed and verified. This laboratory consisted of a chassis dynamometer semi-trailer and an analytic trailer housing a full scale exhaust dilution tunnel and sampling system which mimicked closely the system described in the Code of Federal Regulations for engine certification. The Translab was first used to quantify emissions from natural gas and methanol fueled transit buses, and a second Translab unit was constructed to satisfy research demand. Subsequent emissions measurement was performed on trucks and buses using ethanol, Fischer-Tropsch fuel, and biodiesel. A medium-duty chassis dynamometer was also designed and constructed to facilitate research on delivery vehicles in the 10,000 to 20,000lb range. The Translab participated in major programs to evaluate low-sulfur diesel in conjunction with passively regenerating exhaust particulate filtration technology, and substantial reductions in particulate matter were recorded. The researchers also participated in programs to evaluate emissions from advanced natural gas engines with closed loop feedback control. These natural gas engines showed substantially reduced levels of oxides of nitrogen. For all of the trucks and buses characterized, the levels of carbon monoxide, oxides of nitrogen, hydrocarbons, carbon dioxide and particulate matter were quantified, and in many cases non-regulated species such as aldehydes were also sampled. Particle size was also quantified during selected studies. A laboratory was established at WVU to provide for studies which supported and augmented the Translab research, and to provide for development of superior emissions measurement systems. This laboratory research focused on engine control and fuel sulfur issues. In recent years, as engine and aftertreatment technologies advanced, emissions levels were reduced such that they were at or below the Translab detectable limits, and in the same time frame the US Environmental Protection Agency required improved measurement methodologies for engine emissions certification. To remain current and relevant, the researchers designed a new Translab analytic system, housed in a container which can be transported on a semi-trailer. The new system's dilution tunnel flow was designed to use a subsonic venturi with closed loop control of blower speed, and the secondary dilution and particulate matter filter capture were designed to follow new EPA engine certification procedures. A further contribution of the program has been the development of techniques for creating heavy-duty vehicle test schedules, and the creation of schedules to mimic a variety of truck and bus vocations.

  15. Chemistry and Transport - Combustion Energy Frontier Research Center

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

    Chemistry and Transport Chemistry and Transport The overall goal of the flame chemistry working group is to obtain fundamental combustion and emission properties of low and high pressure flames, to validate kinetic and transport models, and to develop accurate and computationally efficient models capable of predicting turbulent combustion of future transportation fuels. Experimental data of laminar and turbulent flame speeds, flame structures, extinction/ignition limits, and soot/NOx emissions

  16. Pipeline Safety Research, Development and Technology

    Energy Savers [EERE]

    Transportation Pipeline and Hazardous Materials Safety Administration Pipeline Safety Research, Development and Technology Natural Gas Infrastructure R&D and Methane Emissions Mitigation Workshop Nov 2014 U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration Thank You! * We appreciate the opportunity to share! * Much to share about DOT natural gas infrastructure R&D * Many facets to the fugitive methane issue * DOT/DOE - We would like to restart the

  17. X-ray imaging crystal spectroscopy for use in plasma transport research

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect X-ray imaging crystal spectroscopy for use in plasma transport research Citation Details In-Document Search Title: X-ray imaging crystal spectroscopy for use in plasma transport research This research describes advancements in the spectral analysis and error propagation techniques associated with x-ray imaging crystal spectroscopy (XICS) that have enabled this diagnostic to be used to accurately constrain particle, momentum, and heat transport studies in a

  18. Texas Department of Transportation | Open Energy Information

    Open Energy Info (EERE)

    Texas Department of Transportation Jump to: navigation, search Logo: Texas Department of Transportation Name: Texas Department of Transportation Abbreviation: TxDOT Place: Austin,...

  19. NREL: Transportation Research - Power Electronics and Electric Machines

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

    Facilities and Electric Machines Facilities NREL's power electronics and electric machines thermal management test facilities feature a wide range of equipment and enable world-class experimental and modeling capabilities. NREL researchers excel at testing and measurement in the areas of heat transfer, reliability characterization, and thermal and thermomechanical modeling. The following list describes NREL's innovative testing capabilities and equipment. A photo of four researchers in

  20. NREL: Transportation Research - Power Electronics and Electric Machines

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

    Publications and Electric Machines Publications NREL and its partners have produced many papers and presentations related to power electronics and electric machines. For more information about the following publications, contact Sreekant Narumanchi. A photo of a group of researchers sitting around a table with printed publications and laptops. Reports from power electronics and electric machines research are available to the public. Photo by Pat Corkery, NREL Software Spray System Evaluation

  1. NREL: Transportation Research - Renewable Fuels and Lubricants Laboratory

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

    Renewable Fuels and Lubricants Laboratory Photo of a heavy-duty truck being driven on a chassis dynamometer. The heavy-duty chassis dynamometer at the ReFUEL Laboratory simulates on-road driving in a controlled laboratory setting. Photo by Dennis Schroeder, NREL NREL's Renewable Fuels and Lubricants (ReFUEL) Laboratory is a state-of-the-art research and testing facility for advanced fuels and vehicles. Research and development focuses on overcoming barriers to the increased use of renewable

  2. Basic Research Needs for Clean and Efficient Combustion of 21st Century Transportation Fuels

    SciTech Connect (OSTI)

    McIlroy, A.; McRae, G.; Sick, V.; Siebers, D. L.; Westbrook, C. K.; Smith, P. J.; Taatjes, C.; Trouve, A.; Wagner, A. F.; Rohlfing, E.; Manley, D.; Tully, F.; Hilderbrandt, R.; Green, W.; Marceau, D.; O'Neal, J.; Lyday, M.; Cebulski, F.; Garcia, T. R.; Strong, D.

    2006-11-01

    To identify basic research needs and opportunities underlying utilization of evolving transportation fuels, with a focus on new or emerging science challenges that have the potential for significant long-term impact on fuel efficiency and emissions.

  3. NREL: Transportation Research - NREL Serves as the Energy Department's

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

    Showcase for Cutting-Edge Fuel Cell Cars Serves as the Energy Department's Showcase for Cutting-Edge Fuel Cell Cars Research Studies Fueling System, Driver Behavior, and Vehicle Performance January 25, 2016 The Energy Department's National Renewable Energy Laboratory (NREL) recently received a 2015 Tucson Fuel Cell vehicle on loan from Hyundai through a one-year Cooperative Research and Development Agreement and a B-Class F-CELL on loan from Mercedes-Benz to support a one-year Technical

  4. Addressing transportation energy and environmental impacts: technical and policy research directions

    SciTech Connect (OSTI)

    Weissenberger, S.; Pasternak, A.; Smith, J.R.; Wallman, H.

    1995-08-01

    The Lawrence Livermore National Laboratory (LLNL) is establishing a local chapter of the University of California Energy Institute (UCEI). In order to most effectively contribute to the Institute, LLNL sponsored a workshop on energy and environmental issues in transportation. This workshop took place in Livermore on August 10 and brought together researchers from throughout the UC systems in order to establish a joint LLNL-UC research program in transportation, with a focus on energy and environmental impacts.

  5. Lessons learned from bacterial transport research at the South Oyster Site

    SciTech Connect (OSTI)

    Scheibe, T.; Hubbard, S.S.; Onstott, T.C.; DeFlaun, M.F.

    2011-04-01

    This paper provides a review of bacterial transport experiments conducted by a multi-investigator, multi-institution, multi-disciplinary team of researchers under the auspices of the U. S. Department of Energy (DOE). The experiments were conducted during the time period 1999-2001 at a field site near the town of Oyster, Virginia known as the South Oyster Site, and included four major experimental campaigns aimed at understanding and quantifying bacterial transport in the subsurface environment. Several key elements of the research are discussed here: (1) quantification of bacterial transport in physically, chemically and biologically heterogeneous aquifers, (2) evaluation of the efficacy of conventional colloid filtration theory, (3) scale effects in bacterial transport, (4) development of new methods for microbial enumeration and screening for low adhesion strains, (5) application of novel hydrogeophysical techniques for aquifer characterization, and (6) experiences regarding management of a large field research effort. Lessons learned are summarized in each of these areas. The body of literature resulting from South Oyster Site research has been widely cited and continues to influence research into the controls exerted by aquifer heterogeneity on reactive transport (including microbial transport). It also served as a model (and provided valuable experience) for subsequent and ongoing highly-instrumented field research efforts conducted by DOE-sponsored investigators.

  6. NREL: Transportation Research - Electric Vehicle Technologies and Targets

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

    Electric Vehicle Technologies and Targets The U.S. Department of Energy and the cross-agency EV Everywhere Grand Challenge initiative have set goals for plug-in electric vehicles (PEVs) to match the price and driving range of conventional gas-powered vehicles by 2022. NREL teams are working closely with industry partners on battery, power electronics, and climate control innovations designed to reach these targets. Learn more about NREL's research related to EV Everywhere goals, including the

  7. NREL: Transportation Research - Heavy-Duty Vehicle Thermal Management

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

    Heavy-Duty Vehicle Thermal Management Infrared image of a semi cab and two people. NREL testing and modeling assess the energy saving impact of advanced climate control materials and equipment on heavy-duty vehicles. Photo by Dennis Schroeder, NREL Illustration of a truck with labeled energy-saving elements. NREL researchers assess the energy saving potential of films, paints, advanced insulation, micro-environmental design, and idle reduction technologies. Illustration by Ray David, NREL

  8. NREL: Transportation Research - Light-Duty Vehicle Thermal Management

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

    Light-Duty Vehicle Thermal Management Image of a semi-transparent car with parts of the engine highlighted in green. NREL evaluates technologies and methods such as advanced window glazing, cooling heat-pipe systems, parked car ventilation, and direct energy recovery. Illustration by Josh Bauer, NREL National Renewable Energy Laboratory (NREL) researchers are focused on improving the thermal efficiency of light-duty vehicles (LDVs) while maintaining the thermal comfort that drivers expect.

  9. NREL: Transportation Research - Vehicle Thermal Management Models and Tools

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

    Models and Tools image of three models of semi truck cabs. Truck cab models drawn from CAD geometry using CoolCalc (left and center), and a model with overlay of computational fluid dynamics flow (right) indicate areas of heat absorption and loss. Illustrations by Jason Lustbader, Matt Jeffers, and Larry Chaney, NREL The National Renewable Energy Laboratory's (NREL's) vehicle thermal management modeling tools allow researchers to assess the trade-offs and calculate the potential benefits of

  10. Summary of the FY 2005 Batteries for Advanced Transportation Technologies (BATT) Research Program Annual Review

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

    the FY 2005 Batteries for Advanced Transportation Technologies (BATT) Research Program Annual Review May 31-June 2, 2005 Berkeley, CA August 2005 U.S. Department of Energy Office of FreedomCAR and Vehicle Technologies August 8, 2005 Dear Colleague: This document presents a summary of the evaluation and comments provided by the review panel for the FY 2005 Department of Energy (DOE) Batteries for Advanced Transportation Technologies (BATT) program annual review. The review was held at the

  11. AUTHORIZING THE DOT SPECIFICATION 6M PACKAGING FOR CONTINUED USE AT THE SAVANNAH RIVER SITE

    SciTech Connect (OSTI)

    Watkins, R.; Loftin, B.; Hoang, D.

    2010-03-04

    The U.S. Department of Transportation (DOT) Specification 6M packaging was in extensive use for more than 40 years for in-commerce shipments of Type B quantities of fissile and radioactive material (RAM) across the USA, among the Department of Energy (DOE) laboratories, and between facilities in the DOE production complex. In January 2004, the DOT Research and Special Programs Administration (RSPA) Agency issued a final rule in the Federal Register to ammend requirements in the Hazardous Materials Regulations (HMR) pertaining to the transportation of radioactive materials. The final rule became effective on October 1, 2004. One of those changes discontinued the use of the DOT specification 6M, along with other DOT specification packagings, on October 1, 2008. A main driver for the change was due to the fact that 6M specification packagings were not supported by a Safety Analysis Report for Packagings (SARP) that was compliant with Title 10 of the Code of Federal Regulations (CFR) Part 71 (10 CFR 71). The regulatory rules for the discontinued use have been edited in Title 49 of the CFR Parts 100-185, 2004 edition and thereafter. Prior to October 1, 2008, the use of the 6M within the boundaries of the Savannah River Site (SRS), called an onsite transfer, was governed by an onsite transportation document that referenced 49 CFR Parts 100-185. SRS had to develop an Onsite Safety Assessment (OSA) which was independent of 49 CFR in order to justify the continued use of the DOT Specification 6M for the transfer of radioactive material (RAM) at the SRS after October 1, 2008. This paper will discuss the methodology for and difficulties associated with authorizing the DOT Specification 6M Packaging for continued use at the Savannah River Site.

  12. Chevron and NREL to Collaborate on Research to Produce Transportation Fuels

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

    using Algae - News Releases | NREL Chevron and NREL to Collaborate on Research to Produce Transportation Fuels using Algae Joint effort to identify and develop algae strains for feedstock in next-generation biofuels October 31, 2007 Chevron Corporation (NYSE: CVX) and the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) announced today that they have entered into a collaborative research and development agreement to study and advance technology to produce liquid

  13. Research and Development Program for transportation packagings at Sandia National Laboratories

    SciTech Connect (OSTI)

    Hohnstreiter, G.F.; Sorenson, K.B.

    1995-02-01

    This document contains information about the research and development programs dealing with waste transport at Sandia National Laboratories. This paper discusses topics such as: Why new packaging is needed; analytical methodologies and design codes;evaluation of packaging components; materials characterization; creative packaging concepts; packaging engineering and analysis; testing; and certification support.

  14. RKKY interaction in a chirally coupled double quantum dot system

    SciTech Connect (OSTI)

    Heine, A. W.; Tutuc, D.; Haug, R. J.; Zwicknagl, G.; Schuh, D.; Wegscheider, W.

    2013-12-04

    The competition between the Kondo effect and the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction is investigated in a double quantum dots system, coupled via a central open conducting region. A perpendicular magnetic field induces the formation of Landau Levels which in turn give rise to the so-called Kondo chessboard pattern in the transport through the quantum dots. The two quantum dots become therefore chirally coupled via the edge channels formed in the open conducting area. In regions where both quantum dots exhibit Kondo transport the presence of the RKKY exchange interaction is probed by an analysis of the temperature dependence. The thus obtained Kondo temperature of one dot shows an abrupt increase at the onset of Kondo transport in the other, independent of the magnetic field polarity, i.e. edge state chirality in the central region.

  15. Test and evaluation document for DOT Specification 7A type A packaging. Volume 1

    SciTech Connect (OSTI)

    Kelly, D L

    1997-08-04

    The US Department of Energy (DOE) has been conducting, through several of its operating contractors, an evaluation and testing program to qualify Type A radioactive material packagings per US Department of Transportation (DOT) Specification 7A (DOT-7A) of the Code of Federal Regulations (CFR), Title 49, Part 178 (49 CFR 178). This document summarizes the evaluation and testing performed for all of the packagings successfully qualified in this program. This document supersedes DOE Evaluation Document for DOT-7A Type A Packaging (Edling 1987), originally issued in 1987 by Monsanto Research Corporation Mound Laboratory (MLM), Miamisburg, Ohio, for the Department of Energy, Security Evaluation Program (I)P-4. Mound Laboratory issued four revisions to the document between November 1988 and December 1989. In September 1989, the program was transferred to Westinghouse Hanford Company (Westinghouse Hanford) in Richland, Washington. One additional revision was issued in March 1990 by Westinghouse Hanford. This revision reflects the earlier material and incorporates a number of changes. Evaluation and testing activities on 1208 three DOT-7A Program Dockets resulted in the qualification of three new packaging configurations, which are incorporated herein and summarized. This document presents approximately 300 different packagings that have been determined to meet the requirements for a DOT-7A, type A packaging per 49 CFR 178.350.

  16. Nanoscale engineering boosts performance of quantum dot light emitting

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

    diodes Quantum dot light emitting diodes Nanoscale engineering boosts performance of quantum dot light emitting diodes Quantum dots are nano-sized semiconductor particles whose emission color can be tuned by simply changing their dimensions. October 25, 2013 Postdoctoral researcher Young-Shin Park characterizing emission spectra of LEDs in the Los Alamos National Laboratory optical laboratory. Postdoctoral researcher Young-Shin Park characterizing emission spectra of LEDs in the Los Alamos

  17. Scalable quantum computer architecture with coupled donor-quantum dot qubits

    DOE Patents [OSTI]

    Schenkel, Thomas; Lo, Cheuk Chi; Weis, Christoph; Lyon, Stephen; Tyryshkin, Alexei; Bokor, Jeffrey

    2014-08-26

    A quantum bit computing architecture includes a plurality of single spin memory donor atoms embedded in a semiconductor layer, a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, wherein a first voltage applied across at least one pair of the aligned quantum dot and donor atom controls a donor-quantum dot coupling. A method of performing quantum computing in a scalable architecture quantum computing apparatus includes arranging a pattern of single spin memory donor atoms in a semiconductor layer, forming a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, applying a first voltage across at least one aligned pair of a quantum dot and donor atom to control a donor-quantum dot coupling, and applying a second voltage between one or more quantum dots to control a Heisenberg exchange J coupling between quantum dots and to cause transport of a single spin polarized electron between quantum dots.

  18. Letter to Science from Michael Wang, Center for Transportation Research, Argonne National Laboratory

    Alternative Fuels and Advanced Vehicles Data Center [Office of Energy Efficiency and Renewable Energy (EERE)]

    Letter to Science (Original version submitted to Science on Feb. 14 th , 2008; revised on March 14 th , 2008) Michael Wang Center for Transportation Research Argonne National Laboratory Zia Haq Office of Biomass Program Office of Energy Efficiency and Renewable Energy U.S. Department of Energy The article by Searchinger et al. in Sciencexpress ("Use of U.S. Croplands for Biofuels Increases Greenhouse Gases through Emissions from Land Use Change," February 7, 2008) provides a timely

  19. transportation

    National Nuclear Security Administration (NNSA)

    security missions undertaken by the U.S. government.

    Pantex Plant's Calvin Nelson honored as Analyst of the Year for Transportation Security http:nnsa.energy.gov...

  20. Testing of a Transport Cask for Research Reactor Spent Fuel - 13003

    SciTech Connect (OSTI)

    Mourao, Rogerio P.; Leite da Silva, Luiz; Miranda, Carlos A.; Mattar Neto, Miguel; Quintana, Jose F.A.; Saliba, Roberto O.; Novara, Oscar E.

    2013-07-01

    Since the beginning of the last decade three Latin American countries that operate research reactors - Argentina, Brazil and Chile - have been joining efforts to improve the regional capability in the management of spent fuel elements from the TRIGA and MTR reactors operated in the region. A main drive in this initiative, sponsored by the International Atomic Energy Agency, is the fact that no definite solution regarding the back end of the research reactor fuel cycle has been taken by any of the participating country. However, any long-term solution - either disposition in a repository or storage away from reactor - will involve at some stage the transportation of the spent fuel through public roads. Therefore, a licensed cask that provides adequate shielding, assurance of subcriticality, and conformance to internationally accepted safety, security and safeguards regimes is considered a strategic part of any future solution to be adopted at a regional level. As a step in this direction, a packaging for the transport of irradiated fuel for MTR and TRIGA research reactors was designed by the tri-national team and a half-scale model equipped with the MTR version of the internal basket was constructed in Argentina and Brazil and tested in Brazil. Three test campaigns have been carried out so far, covering both normal conditions of transportation and hypothetical accident conditions. After failing the tests in the first two test series, the specimen successfully underwent the last test sequence. A second specimen, incorporating the structural improvements in view of the previous tests results, will be tested in the near future. Numerical simulations of the free drop and thermal tests are being carried out in parallel, in order to validate the computational modeling that is going to be used as a support for the package certification. (authors)

  1. Quantum Dots: Theory

    SciTech Connect (OSTI)

    Vukmirovic, Nenad; Wang, Lin-Wang

    2009-11-10

    This review covers the description of the methodologies typically used for the calculation of the electronic structure of self-assembled and colloidal quantum dots. These are illustrated by the results of their application to a selected set of physical effects in quantum dots.

  2. NRC Technical Research Program to Evaluate Extended Storage and Transportation of Spent Nuclear Fuel - 12547

    SciTech Connect (OSTI)

    Einziger, R.E.; Compton, K.; Gordon, M.; Ahn, T.; Gonzales, H.; Pan, Y.

    2012-07-01

    Any new direction proposed for the back-end of spent nuclear fuel (SNF) cycle will require storage of SNF beyond the current licensing periods. The Nuclear Regulatory Commission (NRC) has established a technical research program to determine if any changes in the 10 CFR part 71, and 72 requirements, and associated guidance might be necessary to regulate the safety of anticipated extended storage, and subsequent transport of SNF. This three part program of: 1) analysis of knowledge gaps in the potential degradation of materials, 2) short-term research and modeling, and 3) long-term demonstration of systems, will allow the NRC to make informed regulatory changes, and determine when and if additional monitoring and inspection of the systems is necessary. The NRC has started a research program to obtain data necessary to determine if the current regulatory guidance is sufficient if interim dry storage has to be extended beyond the currently approved licensing periods. The three-phased approach consists of: - the identification and prioritization of potential degradation of the components related to the safe operation of a dry cask storage system, - short-term research to determine if the initial analysis was correct, and - a long-term prototypic demonstration project to confirm the models and results obtained in the short-term research. The gap analysis has identified issues with the SCC of the stainless steel canisters, and SNF behavior. Issues impacting the SNF and canister internal performance such as high and low temperature distributions, and drying have also been identified. Research to evaluate these issues is underway. Evaluations have been conducted to determine the relative values that various types of long-term demonstration projects might provide. These projects or follow-on work is expected to continue over the next five years. (authors)

  3. WIPP Documents - Transportation

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

    Transportation

  4. Operational guidance for using DOT-6M/2R packaging

    SciTech Connect (OSTI)

    Kelly, D.L.; Hummer, J.H.

    1994-03-01

    The purpose of this paper is to describe a new US Department of Energy (DOE), Transportation Management Division task to create a US Department of Transportation (DOT) Specification 6M/2R packaging configuration user`s guide. The need for a user`s guide was identified because the DOT-6M/2R packaging configuration is widely used by DOE site contractors, and DOE receives many questions about the approved packaging configurations. Currently, two DOE organizations have the authority to approve new DOT-6M/2R configurations. For Defense Programs, the Transportation and Packaging Safety Division (EH-332) administers the program. For Environmental Restoration and Waste Management, the Transportation Management Division (EM-261) administers the program.

  5. Surface Transportation Research and Development Act of 1997. House of Representatives, One Hundred Fifth Congress, Second Session

    SciTech Connect (OSTI)

    1998-12-31

    Mr. Sensenbrenner, from the Committee on Science, submitted this report together with additional views. The Committee on Science, to whom was referred the bill (H.R. 860) to authorize appropriations to the Department of Transportation for surface transportation research and development, and for other purposes, having considered the same, report favorably thereon with an amendment and recommend that the bill as amended do pass.

  6. US Department of Transportation (DOT) Spec 7A Type A evaluation document: Spec 17C 55-gal steel drum with RWMC/SWEPP drum venting system carbon filter assembly

    SciTech Connect (OSTI)

    Edling, D.A.

    1986-09-15

    As part of MRC-Mound's responsibility to coordinate DOE Spec 7A Type A Packaging testing, evaluation, and utilization, this document evaluates per 49CFR 173.415(a) the SWEPP packaging system: DOT Spec 17C steel drums - 30, 55 and 83-gal; High Density Polyethylene (HDPE) liners; and SWEPP DVS Filter Assemblies (two configurations) as a US DOT Spec 7A Type A packaging. A variety of Type A performance testing was done on: DOT Spec 17C 55-gal steel drums; DOT Spec 17C 55-gal steel drums with HDPE liners; and DOT Spec 17C 55-gal steel drums with ''Nucfil'' filters as part of MRC-Mound's Type A Packaging Evaluation Program funded by DOE/HQ, DP-4, Security Evaluations. The subject SWEPP packaging incorporates modifications to the ''Nucfil'' filter and installation assembly previously tested in conjunction with the Spec 17C 55-gal drums. Thus, additional testing was required on the new filter installation in order to evaluate the entire packaging system. This document presents the test data to demonstrate the SWEPP packaging system's performance against the DOT 7A Type A requirements.

  7. Sandia Energy - Sandia Develops a Synthesis of Quantum Dots that...

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

    Develops a Synthesis of Quantum Dots that Increases the Quantum Yield to 95.5% Home Energy Solid-State Lighting Office of Science News Energy Efficiency News & Events Research &...

  8. DOT-7A packaging test procedure

    SciTech Connect (OSTI)

    Kelly, D.L.

    1995-01-23

    This test procedure documents the steps involved with performance testing of Department of Transportation Specification 7A (DOT-7A) Type A packages. It includes description of the performance tests, the personnel involved, appropriate safety considerations, and the procedures to be followed while performing the tests. Westinghouse Hanford Company (WHC) is conducting the evaluation and testing discussed herein for the Department of Energy-Headquarters, Division of Quality Verification and Transportation Safety (EH-321). Please note that this report is not in WHC format. This report is being submitted through the Engineering Documentation System so that it may be used for reference and information purposes.

  9. NREL: Transportation Research - NREL Describes to U.S. Senate Role National

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

    Labs Play in Sustainable Transportation Innovation Describes to U.S. Senate Role National Labs Play in Sustainable Transportation Innovation January 26, 2016 On Thursday, January 21, 2016, NREL's Transportation and Hydrogen Systems Center Director Chris Gearhart provided a testimony on new technologies in the automobile industry before the U.S. Senate Energy and Natural Resources Committee. Members of the committee are currently evaluating a bipartisan bill that will include several

  10. New Los Alamos approach may be key to quantum dot solar cells with real

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

    gains in efficiency Quantum dot solar cells with real gains in efficiency New Los Alamos approach may be key to quantum dot solar cells with real gains in efficiency Researchers have demonstrated an almost four-fold boost of the carrier multiplication yield with nanoengineered quantum dots. June 18, 2014 Core/shell PbSe/CdSe quantum dots (a) and a carrier multiplication (CM) pathway (b) in these nano structures. (a) Transmission electron microscopy image of thick-shell PbSe/CdSe quantum dots

  11. DOE - NNSA/NFO -- EM Radioactive Waste Transportation

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

    Transportation NNSA/NFO Language Options U.S. DOE/NNSA - Nevada Field Office Click to subscribe to NNSS News Radioactive Waste Transportation Transportation photo Government and commercial entities safely transport shipments of radioactive material across the United States in accordance with U.S. Department of Transportation (DOT) requirements. The U.S. Department of Energy (DOE) strictly adheres to all DOT requirements and DOE Orders and Manuals pertaining to the transportation of hazardous and

  12. Geometric spin manipulation in semiconductor quantum dots

    SciTech Connect (OSTI)

    Prabhakar, Sanjay Melnik, Roderick; Inomata, Akira

    2014-04-07

    We propose a method to flip the spin completely by an adiabatic transport of quantum dots. We show that it is possible to flip the spin by inducing a geometric phase on the spin state of a quantum dot. We estimate the geometric spin flip time (approximately 2 ps) which turned out to be much shorter than the experimentally reported decoherence time (approximately 100 ns) that would provide an alternative means of fliping the spin before reaching decoherence. It is important that both the Rashba coupling and the Dresselhaus coupling are present for inducing a phase necessary for spin flip. If one of them is absent, the induced phase is trivial and irrelevant for spin-flip.

  13. Dallas area-wide intelligent transportation system plan. Draft research report, August 1992-August 1996

    SciTech Connect (OSTI)

    Carvell, J.D.; Seymour, E.J.; Walters, C.H.; Starr, T.R.; Balke, K.

    1996-07-01

    This report documents the development of a comprehensive plan for implementation of Intelligent Transportation Systems (ITS) in the Dallas Urban Area. The contract defined objectives: Develop a Broadly Based Steering Committee; Assess Existing Transportation Management Systems and Potential ITS Technology; Identify Institutional Issues and Legal Barriers; Develop an Implementable, Area-Wide Multi-Jurisdictional ITS Plan; and Develop Cost, Benefits, and an Implementation Plan.

  14. Workplace Charging Challenge Partner: U.S. Department of Transportation

    Broader source: Energy.gov [DOE]

    The U.S. Department of Transportation (DOT) is committed to promoting sustainable commuting and work-related travel practices for Federal employees, including initiatives that foster workplace...

  15. The impact of disorder on charge transport in three dimensional...

    Office of Scientific and Technical Information (OSTI)

    Title: The impact of disorder on charge transport in three dimensional quantum dot resonant tunneling structures Efficient iso-entropic energy filtering of electronic waves can be ...

  16. Quantum Dot Materials Can Reduce Heat, Boost Electrical Output - News

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

    Releases | NREL Quantum Dot Materials Can Reduce Heat, Boost Electrical Output May 23, 2005 Golden, Colo. - Researchers at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have shown that nanotechnology may greatly increase the amount of electricity produced by solar cells. In a paper published in a May issue of the American Chemical Society's Nano Letters journal, an NREL team found that tiny "nanocrystals," also known as "quantum dots,"

  17. The effect of Coulomb interactions on thermoelectric properties of quantum dots

    SciTech Connect (OSTI)

    Zimbovskaya, Natalya A.

    2014-03-14

    Thermoelectric effects in a quantum dot coupled to the source and drain charge reservoirs are explored using a nonequilibrium Green's functions formalism beyond the Hartree-Fock approximation. Thermal transport is analyzed within a linear response regime. A transition from Coulomb blockade regime to Kondo regime in thermoelectric transport through a single-level quantum dot is traced using unified approximations for the relevant Green's functions.

  18. 'Giant' Nanocrystal Quantum Dots

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

    'Giant' Nanocrystal Quantum Dots - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs

  19. NREL: Transportation Research - Transportation News

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

    Further Along New fast-filling fuel station dedicated as part of National Hydrogen and Fuel Cell Day. October 30, 2015 NREL Innovation Improves Safety of Electric Vehicle...

  20. NREL Certifies First All-Quantum-Dot Photovoltaic Cell; Demonstrates Stability, Performance (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-02-01

    Researchers at the National Renewable Energy Laboratory (NREL) have certified the first all-quantum-dot photovoltaic cell, which was based on lead sulfide and demonstrated reasonable quantum dot solar cell performance for an initial efficiency measurement along with good stability. The certified open-circuit voltage of the quantum dot cell is greater than that possible from bulk lead sulfide because of quantum confinement.

  1. NREL: Transportation Research - NREL Leads Effort to Get Traffic Moving in

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

    the Right Direction NREL Leads Effort to Get Traffic Moving in the Right Direction Connected Traveler project will guide travelers in energy-efficient manner August 17, 2015 The Energy Department's National Renewable Energy Laboratory (NREL) will serve as the lead organization in developing a tool travelers and transportation officials can use in helping guide people through a city in the most energy-efficient way possible. "Using real-time traffic and GPS data, along with simulations

  2. Transportation Secure Data Center: Real-World Data for Transportation Planning and Land Use Analysis (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-01-01

    The National Renewable Energy Laboratory (NREL) and the U.S. Department of Transportation (DOT) have launched the free, web-based Transportation Secure Data Center (TSDC). The TSDC (www.nrel.gov/tsdc) preserves respondent anonymity while making vital transportation data available to a broad group of users through secure, online access. The TSDC database provides free-of-charge web-based access to valuable transportation data that can be used for: Transit planning, Travel demand modeling, Homeland Security evacuation planning, Alternative fuel station planning, and Validating transportation data from other sources. The TSDC's two levels of access make composite data available with simple online registration, and allow researchers to use detailed spatial data after completing a straight forward application process.

  3. Out-of-Equilibrium Kondo Effect in Double Quantum Dots

    SciTech Connect (OSTI)

    Aguado, Ramon; Langreth, David C.

    2000-08-28

    The out-of-equilibrium transport properties of a double quantum dot system in the Kondo regime are studied theoretically by means of a two-impurity Anderson Hamiltonian with interimpurity hopping. The Hamiltonian is solved by means of a nonequilibrium generalization of the slave-boson mean-field theory. It is demonstrated that measurements of the differential conductance dI/dV , for appropriate values of voltages and tunneling couplings, can give a direct observation of the coherent superposition between the many-body Kondo states of each dot. For large voltages and arbitrarily large interdot tunneling, there is a critical voltage above which the physical behavior of the system again resembles that of two decoupled quantum dots. (c) 2000 The American Physical Society.

  4. DOT-7A Type A packaging design guide

    SciTech Connect (OSTI)

    Kelly, D.L.

    1995-01-23

    The purpose of this Design Guide is to provide instruction for designing a U.S. Department of Transportation Specification 7A (DOT-7A) Type A packaging. Another purpose for this Design Guide is to support the evaluation and testing activities that are performed on new designs by a U.S. Department of Energy (DOE) test facility. This evaluation and testing program is called the DOT-7A Program. When an applicant has determined that a DOT-7A packaging is needed and not commercially available, a design may be created according to this document. The design should include a packaging drawing, specifications, analysis report, operating instructions, and a Packaging Qualification Checklist; all of which should be forwarded to a DOE/HQ approved test facility for evaluation and testing. This report is being submitted through the Engineering Documentation System so that it may be used for reference and information purposes.

  5. A prototype silicon double quantum dot with dispersive microwave readout

    SciTech Connect (OSTI)

    Schmidt, A. R. Henry, E.; Namaan, O.; Siddiqi, I.; Lo, C. C.; Wang, Y.-T.; Bokor, J.; Yablonovitch, E.; Li, H.; Greenman, L.; Whaley, K. B.; Schenkel, T.

    2014-07-28

    We present a unique design and fabrication process for a lateral, gate-confined double quantum dot in an accumulation mode metal-oxide-semiconductor (MOS) structure coupled to an integrated microwave resonator. All electrostatic gates for the double quantum dot are contained in a single metal layer, and use of the MOS structure allows for control of the location of the two-dimensional electron gas via the location of the accumulation gates. Numerical simulations of the electrostatic confinement potential are performed along with an estimate of the coupling of the double quantum dot to the microwave resonator. Prototype devices are fabricated and characterized by transport measurements of electron confinement and reflectometry measurements of the microwave resonator.

  6. Reaction-based Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center

    SciTech Connect (OSTI)

    Tsyh Yeh, Gour

    2007-12-21

    This research sought to examine biogeochemical processes likely to take place in the less conductive materials above and below the gravel during the in situ ethanol biostimulation experiment conducted at Area 2 during 2005-2006. The in situ experiment in turn examined the hypothesis that injection of electron donor into this layer would induce formation of a redox barrier in the less conductive materials, resulting in decreased mass transfer of uranium out these materials and attendant declines in groundwater U(VI) concentration. Our project focuses on the development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. This report summarizes research activities conducted at The University of Central Florida (2004-2007), the development of biogeochemical and reactive transport models and the conduction of numerical simulations at laboratory, column, and field scales.

  7. Shiny quantum dots brighten future of solar cells

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

    Shiny quantum dots brighten future of solar cells Shiny quantum dots brighten future of solar ... dots can be applied in solar energy by helping more efficiently harvest sunlight. ...

  8. Nanoscale engineering boosts performance of quantum dot light...

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

    Quantum dot light emitting diodes Nanoscale engineering boosts performance of quantum dot light emitting diodes Quantum dots are nano-sized semiconductor particles whose emission...

  9. Regulatory compliance guide for DOT-7A type A packaging design

    SciTech Connect (OSTI)

    Kelly, D.L.

    1996-06-04

    The purpose of this guide is to provide instruction for assuring that the regulatory design requirements for a DOT-7A Type A packaging are met. This guide also supports the testing and evaluation activities that are performed on new packaging designs by a DOE-approved test facility through the DOE`s DOT-7A Test Program. This Guide was updated to incorporate regulatory changes implemented by HM-169A (49 CFR, `Transportation`).

  10. Enforcement Guidance Supplement 98-02: DOE Enforcement Activities where Off-site Transportation Issues are also Present.

    Broader source: Energy.gov [DOE]

    Recently several questions have arisen regarding the scope of Price-Anderson enforcement when transportation issues are directly or indirectly involved in an incident. These questions can be separated into two areas, (1) transportation issues that involve on-site transportation typically not regulated by the Department of Transportation (DOT), and (2) transportation issues that involve off-site transportation. This guidance addresses off-site transportation that is regulated by DOT and other state and federal agencies.

  11. Computational models for the berry phase in semiconductor quantum dots

    SciTech Connect (OSTI)

    Prabhakar, S. Melnik, R. V. N.; Sebetci, A.

    2014-10-06

    By developing a new model and its finite element implementation, we analyze the Berry phase low-dimensional semiconductor nanostructures, focusing on quantum dots (QDs). In particular, we solve the Schrdinger equation and investigate the evolution of the spin dynamics during the adiabatic transport of the QDs in the 2D plane along circular trajectory. Based on this study, we reveal that the Berry phase is highly sensitive to the Rashba and Dresselhaus spin-orbit lengths.

  12. Transportation Systems Modeling

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

    TRACC RESEARCH Computational Fluid Dynamics Computational Structural Mechanics Transportation Systems Modeling TRANSPORTATION SYSTEMS MODELING Overview of TSM Transportation systems modeling research at TRACC uses the TRANSIMS (Transportation Analysis SIMulation System) traffic micro simulation code developed by the U.S. Department of Transportation (USDOT). The TRANSIMS code represents the latest generation of traffic simulation codes developed jointly under multiyear programs by USDOT, the

  13. NREL: Transportation Research - Facilities

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

    ... energy systems, utility grids, renewable energy sources, and plug-in electric vehicles. ... electric vehicle communication with the smart grid and to create opportunities for ...

  14. NREL: Transportation Research - Publications

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

    publications related to our vehicles and fuels projects: Clean Cities Electric Vehicle Grid Integration Energy Storage Fleet Test and Evaluation Fuels Performance Power...

  15. Photocurrent extraction efficiency in colloidal quantum dot photovoltaics

    SciTech Connect (OSTI)

    Kemp, K. W.; Wong, C. T. O.; Hoogland, S. H.; Sargent, E. H.

    2013-11-18

    The efficiency of photocurrent extraction was studied directly inside operating Colloidal Quantum Dot (CQD) photovoltaic devices. A model was derived from first principles for a thin film p-n junction with a linearly spatially dependent electric field. Using this model, we were able to clarify the origins of recent improvement in CQD solar cell performance. From current-voltage diode characteristics under 1 sun conditions, we extracted transport lengths ranging from 39 nm to 86 nm for these materials. Characterization of the intensity dependence of photocurrent extraction revealed that the dominant loss mechanism limiting the transport length is trap-mediated recombination.

  16. What the Blank Makes Quantum Dots Blink?

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

    What the Blank Makes Quantum Dots Blink? What the Blank Makes Quantum Dots Blink? Calculations confirm that surface flaws are behind fluorescence intermittency in silicon nanocrystals June 15, 2015 Contact: Margie Wylie, mwylie@lbl.gov, +1 510 486 7421 Quantum dots are semiconductors just a few nanometers in diameter that can glow Quantum dots (shown here dissolved in liquid under ultraviolet light) offer tantalizing prospects for new technologies if scientists can stop them blinking. (Photo by

  17. Transportation Secure Data Center: Real-World Data for Environmental and Air Quality Analysis (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-01-01

    The National Renewable Energy Laboratory (NREL) and the U.S. Department of Transportation (DOT) have launched the free, web-based Transportation Secure Data Center (TSDC). The TSDC (www.nrel.gov/tsdc) preserves respondent anonymity while making vital transportation data available to a broad group of users through secure, online access. The TSDC database provides free-of-charge web-based access to valuable transportation data that can be used for: Emissions and air pollution modeling, Vehicle energy and power analysis, Climate change impact studies, Alternative fuel station planning, and Validating transportation data from other sources. The TSDC's two levels of access make composite data available with simple online registration, and allow researchers to use detailed spatial data after completing a straight forward application process.

  18. Hazardous Materials Transportation Authorization Act of 1993. Introduced in the Senate of the United States. Report of the Senate Committee on Commerce, Science, and Transportation, One Hundred Third Congress, First Session

    SciTech Connect (OSTI)

    1993-12-31

    The report addresses a bill (S. 1640) to amend the Hazardous Materials Transportation Act (HMTA). The bill authorizes appropriations. This legislation would authorized funding of the HMTA by the Department of Transportation (DOT) as program manager. The DOT is required to take a number of significant steps to improve hazmat transportation safety. The legislative text of the Bill is summarized with amendments.

  19. Induced spin-accumulation and spin-polarization in a quantum-dot ring by using magnetic quantum dots and Rashba spin-orbit effect

    SciTech Connect (OSTI)

    Eslami, L., E-mail: Leslami@iust.ac.ir; Faizabadi, E. [School of Physics, Iran University of Science and Technology, Tehran 16846 (Iran, Islamic Republic of)

    2014-05-28

    The effect of magnetic contacts on spin-dependent electron transport and spin-accumulation in a quantum ring, which is threaded by a magnetic flux, is studied. The quantum ring is made up of four quantum dots, where two of them possess magnetic structure and other ones are subjected to the Rashba spin-orbit coupling. The magnetic quantum dots, referred to as magnetic quantum contacts, are connected to two external leads. Two different configurations of magnetic moments of the quantum contacts are considered; the parallel and the anti-parallel ones. When the magnetic moments are parallel, the degeneracy between the transmission coefficients of spin-up and spin-down electrons is lifted and the system can be adjusted to operate as a spin-filter. In addition, the accumulation of spin-up and spin-down electrons in non-magnetic quantum dots are different in the case of parallel magnetic moments. When the intra-dot Coulomb interaction is taken into account, we find that the electron interactions participate in separation between the accumulations of electrons with different spin directions in non-magnetic quantum dots. Furthermore, the spin-accumulation in non-magnetic quantum dots can be tuned in the both parallel and anti-parallel magnetic moments by adjusting the Rashba spin-orbit strength and the magnetic flux. Thus, the quantum ring with magnetic quantum contacts could be utilized to create tunable local magnetic moments which can be used in designing optimized nanodevices.

  20. Research and development of proton-exchange membrane (PEM) fuel cell system for transportation applications. Phase I final report

    SciTech Connect (OSTI)

    1996-01-01

    Objective during Phase I was to develop a methanol-fueled 10-kW fuel cell power source and evaluate its feasibility for transportation applications. This report documents research on component (fuel cell stack, fuel processor, power source ancillaries and system sensors) development and the 10-kW power source system integration and test. The conceptual design study for a PEM fuel cell powered vehicle was documented in an earlier report (DOE/CH/10435-01) and is summarized herein. Major achievements in the program include development of advanced membrane and thin-film low Pt-loaded electrode assemblies that in reference cell testing with reformate-air reactants yielded performance exceeding the program target (0.7 V at 1000 amps/ft{sup 2}); identification of oxidation catalysts and operating conditions that routinely result in very low CO levels ({le} 10 ppm) in the fuel processor reformate, thus avoiding degradation of the fuel cell stack performance; and successful integrated operation of a 10-kW fuel cell stack on reformate from the fuel processor.

  1. Photo-induced conductance fluctuations in mesoscopic Ge/Si systems with quantum dots

    SciTech Connect (OSTI)

    Stepina, N. P.; Dvurechenskii, A. V.; Nikiforov, A. I.; Moers, J.; Gruetzmacher, D.

    2014-08-20

    We study the evolution of electron transport in strongly localized mesoscopic system with quantum dots under small photon flux. Exploring devices with narrow transport channels lead to the observation of giant fluctuations of the photoconductance, which is attributed to the strong dependence of hopping current on the filling of dots by holes. In our experiments, single-photon mode operation is indicated by the linear dependence of the frequency of photo-induced fluctuations on the light intensity and the step-like response of conductance on the pulse excitation. The effect of the light wavelength, measurement temperature, size of the conductive channel on the device efficiency are considered.

  2. Safety analysis report for packaging: the ORNL DOT specification 6M - special form package

    SciTech Connect (OSTI)

    Schaich, R.W.

    1982-07-01

    The ORNL DOT Specification 6M - Special Form Package was fabricated at the Oak Ridge Nation al Laboratory (ORNL) for the transport of Type B solid non-fissile radioactive materials in special form. The package was evaluated on the basis of tests performed by the Dow Chemical Company, Rocky Flats Division, on the DOT-6M container and special form tests performed on a variety of stainless steel capsules at ORNL by Operations Division personnel. The results of these evaluations demonstrate that the package is in compliance with the applicable regulations for the transport of Type B quantities in special form of non-fissile radioactive materials.

  3. Modeling of the quantum dot filling and the dark current of quantum dot infrared photodetectors

    SciTech Connect (OSTI)

    Ameen, Tarek A.; El-Batawy, Yasser M.; Abouelsaood, A. A.

    2014-02-14

    A generalized drift-diffusion model for the calculation of both the quantum dot filling profile and the dark current of quantum dot infrared photodetectors is proposed. The confined electrons inside the quantum dots produce a space-charge potential barrier between the two contacts, which controls the quantum dot filling and limits the dark current in the device. The results of the model reasonably agree with a published experimental work. It is found that increasing either the doping level or the temperature results in an exponential increase of the dark current. The quantum dot filling turns out to be nonuniform, with a dot near the contacts containing more electrons than one in the middle of the device where the dot occupation approximately equals the number of doping atoms per dot, which means that quantum dots away from contacts will be nearly unoccupied if the active region is undoped.

  4. Caged Quantum Dots

    ScienceCinema (OSTI)

    Cohen, Bruce

    2013-05-29

    Berkeley Lab scientists have developed a nanosized crystal that lights up on command, a feat that could allow researchers to more easily observe individual proteins inside cells. http://newscenter.lbl.gov/feature-stories/2008/11/18/cagedquantumdots/

  5. Tunnel magnetoresistance and linear conductance of double quantum dots strongly coupled to ferromagnetic leads

    SciTech Connect (OSTI)

    Weymann, Ireneusz

    2015-05-07

    We analyze the spin-dependent linear-response transport properties of double quantum dots strongly coupled to external ferromagnetic leads. By using the numerical renormalization group method, we determine the dependence of the linear conductance and tunnel magnetoresistance on the degree of spin polarization of the leads and the position of the double dot levels. We focus on the transport regime where the system exhibits the SU(4) Kondo effect. It is shown that the presence of ferromagnets generally leads the suppression of the linear conductance due to the presence of an exchange field. Moreover, the exchange field gives rise to a transition from the SU(4) to the orbital SU(2) Kondo effect. We also analyze the dependence of the tunnel magnetoresistance on the double dot levels' positions and show that it exhibits a very nontrivial behavior.

  6. DOE TMD transportation training module 14 transportation of explosives

    SciTech Connect (OSTI)

    Griffith, R.L. Jr.

    1994-07-01

    The Department of Energy Transportation Management Division has developed training module 14, entitled {open_quotes}Transportation of Explosives{close_quotes} to compliment the basic {open_quotes}core ten{close_quotes} training modules of the Hazardous Materials Modular Training Program. The purpose of this training module is to increase awareness of the Department of Transportation (DOT) requirements concerning the packaging and transportation of explosives. Topics covered in module 14 include the classification of explosives, approval and registration of explosives, packaging requirements, hazard communication requirements, separation and segregation compatibility requirements, loading and unloading operations, as well as safety measures required in the event of a vehicle accident involving explosives.

  7. Final Progress Report for Project Entitled: Quantum Dot Tracers for Use in Engineered Geothermal Systems

    SciTech Connect (OSTI)

    Rose, Peter; Bartl, Michael; Reimus, Paul; Williams, Mark; Mella, Mike

    2015-09-12

    The objective of this project was to develop and demonstrate a new class of tracers that offer great promise for use in characterizing fracture networks in EGS reservoirs. From laboratory synthesis and testing through numerical modeling and field demonstrations, we have demonstrated the amazing versatility and applicability of quantum dot tracers. This report summarizes the results of four years of research into the design, synthesis, and characterization of semiconductor nanocrystals (quantum dots) for use as geothermal tracers.

  8. SUNY/Buffalo Developing High-Efficiency Colloidal Quantum Dot Phosphors |

    Energy Savers [EERE]

    Department of Energy Research & Development » R&D Highlights » SUNY/Buffalo Developing High-Efficiency Colloidal Quantum Dot Phosphors SUNY/Buffalo Developing High-Efficiency Colloidal Quantum Dot Phosphors Photo of a synthesis flask containing newly formed nanocrystal emitters. The emitters show bright yellow luminescence. The State University of New York at Buffalo is working to reduce the cost and increase the performance of LEDs for general illumination by developing

  9. Research

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

    Research Research Isotopes produced at Los Alamos National Laboratory are saving lives, advancing cutting-edge research and keeping the U.S. safe. Research thorium test foil A thorium test foil target for proof-of-concept actinium-225 production In addition to our routine isotope products, the LANL Isotope Program is focused on developing the next suite of isotopes and services to meet the Nation's emerging needs. The LANL Isotope Program's R&D strategy is focused on four main areas (see

  10. Transportation Secure Data Center: Real-World Data for Planning, Modeling and Analysis (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-01-01

    The National Renewable Energy Laboratory (NREL) and the U.S. Department of Transportation (DOT) have launched the free, web-based Transportation Secure Data Center (TSDC). The TSDC (www.nrel.gov/tsdc) preserves respondent anonymity while making vital transportation data available to a broad group of users through secure, online access. The TSDC database gives, metropolitan planning organizations, universities, national laboratories, air quality management districts, disaster planning agencies and auto manufacturers free-of-charge web-based access to valuable transportation data. The TSDC's two levels of access make composite data available with simple online registration, and allow researchers to use detailed spatial data after completing a straight forward application process.

  11. Quantum Dot Light Emitting Diode

    SciTech Connect (OSTI)

    Keith Kahen

    2008-07-31

    The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m2, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.

  12. Quantum Dot Light Emitting Diode

    SciTech Connect (OSTI)

    Kahen, Keith

    2008-07-31

    The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m{sup 2}, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.

  13. The dosimetric consequences of the new DOT LSA definition

    SciTech Connect (OSTI)

    Mis, F.J.

    1996-10-01

    As a result of the new regulations for the transportation of radioactive materials, the DOT and the NRC have implemented a rule designed to limit the activity in an LSA container. This is a new regulation designed to insure that the spirit of the law as well as the letter of the law are followed for LSA shipments. Specifically, it limits the dose rate at any location on an unshielded LSA container to less than 1 rem/hr at 3 meters. Other possible alternatives had been discussed prior to the implementation of this regulation including multiples of A{sub 2} values, as implemented by the French.

  14. Generation of even harmonics in coupled quantum dots (Journal...

    Office of Scientific and Technical Information (OSTI)

    Generation of even harmonics in coupled quantum dots Citation Details In-Document Search Title: Generation of even harmonics in coupled quantum dots Using the spatial-temporal...

  15. Next-Generation "Giant" Quantum Dots: Performance-Engineered...

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

    "Giant" Quantum Dots: Performance-Engineered for Lighting Next-Generation "Giant" Quantum Dots: Performance-Engineered for Lighting Lead Performer: Los Alamos National Laboratory - ...

  16. The Fluid Interface Reactions Structures and Transport (FIRST) EFRC (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    ScienceCinema (OSTI)

    Wesolowski, David J. (Director, FIRST - Fluid Interface Reactions, Structures, and Transport Center); FIRST Staff

    2011-11-02

    'The Fluid Interface Reactions Structures and Transport (FIRST) EFRC' was submitted by FIRST to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. FIRST, an EFRC directed by David J. Wesolowski at the Oak Ridge National Laboratory is a partnership of scientists from nine institutions: Oak Ridge National Laboratory (lead), Argonne National Laboratory, Drexel University, Georgia State University, Northwestern University, Pennsylvania State University, Suffolk University, Vanderbilt University, and University of Virginia. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges. The mission of Fluid Interface Reactions, Structures and Transport Center is 'to develop quantitative and predictive models of the unique nanoscale environment at fluid-solid interfaces that will enable transformational advances in electrical energy storage and heterogeneous catalysis for solar fuels.' Research topics are: catalysis (biomass, CO{sub 2}, water), electrocatalysis, photocatalysis, photoelectrocatalysis, solar fuels, solar electrodes, electrical energy storage, batteries, capacitors, battery electrodes, electrolytes, extreme environment, CO{sub 2} (convert), greenhouse gas, microelectromechanical systems (MEMS), interfacial characterization, matter by design, novel materials synthesis, and charge transport.

  17. Test and evaluation document for DOT Specification 7A Type A Packaging. Revision 3

    SciTech Connect (OSTI)

    1996-01-30

    The US Department of Energy (DOE) has been conducting, through several of its operating contractors, an evaluation and testing program to qualify Type A radioactive material packagings per US Department of Transportation (DOT) Specification 7A (DOT-7A) of the Code of Federal Regulations (CFR), Title 49, Part 178 (49 CFR 178). The program is currently administered by the DOE, Office of Facility Safety Analysis, DOE/EH-32, at DOE-Headquarters (DOE-HQ) in Germantown, Maryland. This document summarizes the evaluation and testing performed for all of the packagings successfully qualified in this program.

  18. Research Highlight

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

    Initial Aerosol Concentration Is Key Contributor to Low-Level Cloud Reflectivity Submitter: Penner, J. E., University of Michigan Area of Research: Aerosol Properties Working Group(s): Aerosol Journal Reference: Penner, J., Dong, X., Chen. Y., Observational evidence of a change in radiative forcing due to the indirect aerosol effect, Nature, Vol. 427, 15 January 2004. Cloud optical depth, as determined from the parcel model, is indicated by the dots. Red lines show best fit data of cloud liquid

  19. Single-dot optical emission from ultralow density well-isolated InP quantum dots

    SciTech Connect (OSTI)

    Ugur, A.; Hatami, F.; Masselink, W. T.; Vamivakas, A. N.; Lombez, L.; Atatuere, M.

    2008-10-06

    We demonstrate a straightforward way to obtain single well-isolated quantum dots emitting in the visible part of the spectrum and characterize the optical emission from single quantum dots using this method. Self-assembled InP quantum dots are grown using gas-source molecular-beam epitaxy over a wide range of InP deposition rates, using an ultralow growth rate of about 0.01 atomic monolayers/s, a quantum-dot density of 1 dot/{mu}m{sup 2} is realized. The resulting isolated InP quantum dots embedded in an InGaP matrix are individually characterized without the need for lithographical patterning and masks on the substrate. Such low-density quantum dots show excitonic emission at around 670 nm with a linewidth limited by instrument resolution. This system is applicable as a single-photon source for applications such as quantum cryptography.

  20. Thick-shell nanocrystal quantum dots

    DOE Patents [OSTI]

    Hollingsworth, Jennifer A. (Los Alamos, NM); Chen, Yongfen (Eugene, OR); Klimov, Victor I. (Los Alamos, NM); Htoon, Han (Los Alamos, NM); Vela, Javier (Los Alamos, NM)

    2011-05-03

    Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.

  1. Theory Of Alkyl Terminated Silicon Quantum Dots

    SciTech Connect (OSTI)

    Reboredo, F; Galli, G

    2004-08-19

    We have carried out a series of ab-initio calculations to investigate changes in the optical properties of Si quantum dots as a function of surface passivation. In particular, we have compared hydrogen passivated dots with those having alkyl groups at the surface. We find that, while on clusters with reconstructed surfaces a complete alkyl passivation is possible, steric repulsion prevents full passivation of Si dots with unreconstructed surfaces. In addition, our calculations show that steric repulsion may have a dominant effect in determining the surface structure, and eventually the stability of alkyl passivated clusters, with results dependent on the length of the carbon chain. Alkyl passivation weakly affects optical gaps of silicon quantum dots, while it substantially decreases ionization potentials and electron affinities and affect their excited state properties. On the basis of our results we propose that alkyl terminated quantum dots may be size selected taking advantage of the change in ionization potential as a function of the cluster size.

  2. Supertruck - Improving Transportation Efficiency through Integrated...

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

    Improving Transportation Efficiency through Integrated Vehicle, Engine and Powertrain Research Supertruck - Improving Transportation Efficiency through Integrated Vehicle, Engine ...

  3. Research Highlight

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

    10.10022014JD023022. Figure 1. Two distinguished CBHs are defined by both ceilometer (black dots) and MPL (pink dots) measurements. Previous studies reveal the unique structure...

  4. NREL: Transportation Research - Transportation and Hydrogen Newsletter...

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

    partners, including original equipment manufacturers, suppliers, fleets, national labs, Clean Cities coalitions, the Energy Department, the Federal Highway Administration, the...

  5. NREL: Transportation Research - Transportation Secure Data Center

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

    of miles of travel, along with vehicle characteristics and survey participant demographics. NREL screens the initial data for quality control, translates each data set into a...

  6. Women @ Energy: Dot Harris | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    LaDoris (Dot) Harris is the Director of the Office of Economic Impact and Diversity. LaDoris (Dot) Harris is the Director of the Office of Economic Impact and Diversity. LaDoris (Dot) Harris is the Director of the Office of Economic Impact and Diversity. She was nominated by President Obama and confirmed by the U.S. Senate on March 29, 2012. She has served at some of the world's largest firms including General Electric, ABB Service, and Westinghouse Electric Company. Ms. Harris leads the

  7. Investigation of size dependent structural and optical properties of thin films of CdSe quantum dots

    SciTech Connect (OSTI)

    Sharma, Madhulika; Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay, Powai, Mumbai 400076 ; Sharma, A.B.; Mishra, N.; Pandey, R.K.

    2011-03-15

    Research highlights: {yields} CdSe q-dots have been synthesized using simple chemical synthesis route. {yields} Thin film of CdSe quantum dots exhibited self-organized growth. {yields} Size dependent blue shift observed in the absorption edge of CdSe nanocrystallites. {yields} PL emission band corresponds to band edge luminescence and defect luminescence. {yields} Organized growth led to enhancement in luminescence yield of smaller size Q-dots. -- Abstract: Cadmium selenide (CdSe) quantum dots were grown on indium tin oxide substrate using wet chemical technique for possible application as light emitting devices. The structural, morphological and luminescence properties of the as deposited thin films of CdSe Q-dot have been investigated, using X-ray diffraction, transmission electron microscopy, atomic force microscopy and optical and luminescence spectroscopy. The quantum dots have been shown to deposit in an organized array on ITO/glass substrate. The as grown Q-dots exhibited size dependent blue shift in the absorption edge. The effect of quantum confinement also manifested as a blue shift of photoluminescence emission. It is shown that the nanocrystalline CdSe exhibits intense photoluminescence as compared to the large grained polycrystalline CdSe films.

  8. First principle thousand atom quantum dot calculations

    SciTech Connect (OSTI)

    Wang, Lin-Wang; Li, Jingbo

    2004-03-30

    A charge patching method and an idealized surface passivation are used to calculate the single electronic states of IV-IV, III-V, II-VI semiconductor quantum dots up to a thousand atoms. This approach scales linearly and has a 1000 fold speed-up compared to direct first principle methods with a cost of eigen energy error of about 20 meV. The calculated quantum dot band gaps are parametrized for future references.

  9. integrated-transportation-models

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

    Training Archive Integrated Transportation Models Workshop at ITM 2012 April 29, 2012 Hyatt Regency Tampa Hosted by: The Transportation Research and Analysis Computing Center at Argonne National Laboratory This email address is being protected from spambots. You need JavaScript enabled to view it. The aim of the workshop was to provide an opportunity for researchers and practitioners to discuss recent research results that can support a wider application of integrated transportation models,

  10. Weather and the Transport of Hazardous Materials

    Office of Environmental Management (EM)

    FHWA R d W h M P FHWA R d W h M P FHWA Road Weather Management Program FHWA Road Weather Management Program " "Weather and the transport of Hazardous Materials" Ray Murphy Office of Technical Services Ray Murphy, Office of Technical Services U.S. DOT - Federal Highway Administration Breako t Session Using Technolog to Dispatch U.S. DOE National Transportation Stakeholder Forum Breakout Session: Using Technology to Dispatch and Monitor Shipments During Adverse Conditions

  11. Approaches to Future Generation Photovoltaics and Solar Fuels: Quantum Dots, Arrays, and Quantum Dot Solar Cells

    SciTech Connect (OSTI)

    Semonin, O.; Luther, J.; Beard, M.; Johnson, J.; Gao, J.; Nozik, A.

    2012-01-01

    One potential, long-term approach to more efficient and lower cost future generation solar cells for solar electricity and solar fuels is to utilize the unique properties of quantum dots (QDs) to control the relaxation pathways of excited states to enhance multiple exciton generation (MEG). We have studied MEG in close-packed PbSe QD arrays where the QDs are electronically coupled in the films and thus exhibit good transport while still maintaining quantization and MEG. We have developed simple, all-inorganic solution-processable QD solar cells that produce large short-circuit photocurrents and power conversion efficiencies above 5% via nanocrystalline p-n junctions. These solar cells show QYs for photocurrent that exceed 100% in the photon energy regions where MEG is possible; the photocurrent MEG QYs as a function of photon energy match those determined via time-resolved spectroscopy Recent analyses of the major effect of MEG combined with solar concentration on the conversion efficiency of solar cells will also be discussed.

  12. Reaction-Based Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center

    SciTech Connect (OSTI)

    Yeh, Gour-Tsyh

    2006-06-01

    This research project (started Fall 2004) was funded by a grant to The Pennsylvania State University, University of Central Florida, and The University of Alabama in the Integrative Studies Element of the NABIR Program (DE-FG04-ER63914/63915/63196). Dr. Eric Roden, formerly at The University of Alabama, is now at the University of Wisconsin - Madison. Our project focuses on the development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. This work builds on our previous studies of microbial Fe(III) and U(VI) reduction, and is directly aligned with the Scheibe et al. NABIR FRC Field Project at Area 2.

  13. Current Research

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

    Current Research The U.S. Department of Transportation (USDOT) has established its only high-performance computing and engineering analysis research facility at Argonne National Laboratory to provide applications support in key areas of applied research and development for the USDOT community. The Transportation Research and Analysis Computing Center (TRACC) features a state-of-the-art massively parallel computer system, advanced scientific visualization capability, high-speed network

  14. Reaction-Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center

    SciTech Connect (OSTI)

    Burgos, W.D.

    2009-09-02

    This report summarizes research conducted in conjunction with a project entitled “Reaction-Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center”, which was funded through the Integrative Studies Element of the former NABIR Program (now the Environmental Remediation Sciences Program) within the Office of Biological and Environmental Research. Dr. William Burgos (The Pennsylvania State University) was the overall PI/PD for the project, which included Brian Dempsey (Penn State), Gour-Tsyh (George) Yeh (Central Florida University), and Eric Roden (formerly at The University of Alabama, now at the University of Wisconsin) as separately-funded co-PIs. The project focused on development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. The work builds on our previous studies of microbial Fe(III) and U(VI) reduction, and was directly aligned with the Scheibe et al. ORNL FRC Field Project at Area 2.

  15. Current status, research needs, and opportunities in applications of surface processing to transportation and utilities technologies. Proceedings of a December 1991 workshop

    SciTech Connect (OSTI)

    Czanderna, A.W.; Landgrebe, A.R.

    1992-09-01

    Goal of surface processing is to develop innovative methods of surface modification and characterization for optimum performance and environmental protection for cost-effective operational lifetimes of systems, materials, and components used in transportation and utilities. These proceedings document the principal discussions and conclusions reached at the workshop; they document chapters about the current status of surface characterization with focus on composition, structure, bonding, and atomic-scale topography of surfaces. Also documented are chapters on the current status of surface modification techniques: electrochemical, plasma-aided, reactive and nonreactive physical vapor deposition, sol-gel coatings, high-energy ion implantation, ion-assisted deposition, organized molecular assemblies, solar energy. Brief chapters in the appendices document basic research in surface science by NSF, Air Force, and DOE. Participants at the workshop were invited to serve on 10 working groups. Separate abstracts were prepared for the data base where appropriate.

  16. Carrier multiplication detected through transient photocurrent in device-grade films of lead selenide quantum dots

    SciTech Connect (OSTI)

    Gao, Jianbo; Fidler, Andrew F.; Klimov, Victor I.

    2015-09-08

    In carrier multiplication, the absorption of a single photon results in two or more electronhole pairs. Quantum dots are promising materials for implementing carrier multiplication principles in real-life technologies. So far, however, most of research in this area has focused on optical studies of solution samples with yet to be proven relevance to practical devices. We report ultra-fast electro-optical studies of device-grade films of electronically coupled quantum dots that allow us to observe multiplication directly in the photocurrent. Our studies help rationalize previous results from both optical spectroscopy and steady-state photocurrent measurements and also provide new insights into effects of electric field and ligand treatments on multiexciton yields. Importantly, we demonstrate that using appropriate chemical treatments of the films, extra charges produced by carrier multiplication can be extracted from the quantum dots before they are lost to Auger recombination and hence can contribute to photocurrent of practical devices.

  17. Structure in solution of the RNAter dot DNA hybrid (rA) sub 8 ter dot (dT)

    Office of Scientific and Technical Information (OSTI)

    sub 8 determined by NMR and Raman spectroscopy (Journal Article) | SciTech Connect Structure in solution of the RNAter dot DNA hybrid (rA) sub 8 ter dot (dT) sub 8 determined by NMR and Raman spectroscopy Citation Details In-Document Search Title: Structure in solution of the RNAter dot DNA hybrid (rA) sub 8 ter dot (dT) sub 8 determined by NMR and Raman spectroscopy The solution structure of the hybrid RNA{center dot}DNA octamer (rA){sub 8}{center dot}(dT){sub 8} has been determined by

  18. Surface treatment of nanocrystal quantum dots after film deposition

    DOE Patents [OSTI]

    Sykora, Milan; Koposov, Alexey; Fuke, Nobuhiro

    2015-02-03

    Provided are methods of surface treatment of nanocrystal quantum dots after film deposition so as to exchange the native ligands of the quantum dots for exchange ligands that result in improvement in charge extraction from the nanocrystals.

  19. ARM - Research Highlights

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

    CenterResearch Highlights Media Contact Hanna Goss hanna-dot-goss-at-pnnl-dot-gov @armnewsteam Field Notes Blog Topics Field Notes107 AGU 3 AMIE 10 ARM Aerial Facility 2 ARM Mobile Facility 1 6 ARM Mobile Facility 2 47 ARM Mobile Facility 3 1 BAECC 1 BBOP 4 ENA 1 GOAMAZON 7 MAGIC 15 MC3E 17 PECAN 3 SGP 7 STORMVEX 29 TCAP 3 Search News Search Blog News Center All Categories What's this? Social Media Guidance News Center All Categories Features and Releases Facility News Field Notes Blog Events

  20. Coupling of Time-Dependent Neutron Transport Theory with the Thermal Hydraulics Code ATHLET and Application to the Research Reactor FRM-II

    SciTech Connect (OSTI)

    Pautz, Andreas; Birkhofer, Adolf

    2003-11-15

    We introduce a new coupled neutronics/thermal hydraulics code system for analyzing transients of nuclear power plants and research reactors, based on a neutron transport theory approach. For the neutron kinetics, we have developed the code DORT-TD, a time-dependent extension of the well-known discrete ordinates code DORT. DORT-TD uses a fully implicit time integration scheme and is coupled via a general interface to the thermal hydraulics system code ATHLET, a generally applicable code for the analyses of LWR accident scenarios. Feedback is accounted for by interpolating multigroup cross sections from precalculated libraries, which are generated in advance for user-specified, discrete sets of thermal hydraulic parameters, e.g., fuel and coolant temperature. The coupled code system is applied to the high-flux research reactor FRM-II (Germany). Several design basis accidents are considered, namely the unintended control rod withdrawal, the loss of offsite power, and the loss of the secondary heat sink as well as a hypothetical transient with large reactivity insertion.

  1. Fuel Cell Demonstration Project - 200 kW - Phosphoric Acid Fuel Cell Power Plant Located at the National Transportation Research Center: FINAL REPORT

    SciTech Connect (OSTI)

    Berry, JB

    2005-05-06

    Oak Ridge National Laboratory (ORNL) researches and develops distributed generation technology for the Department of Energy, Energy Efficiency and Renewable Energy Distributed Energy Program. This report describes installation and operation of one such distributed generation system, a United Technology Corporation fuel cell located at the National Transportation Research Center in Knoxville, Tennessee. Data collected from June 2003 to June of 2004, provides valuable insight regarding fuel cell-grid compatibility and the cost-benefit of the fuel cell operation. The NTRC fuel cell included a high-heat recovery option so that use of thermal energy improves project economics and improves system efficiency to 59% year round. During the year the fuel cell supplied a total of 834MWh to the NTRC and provided 300MBtu of hot water. Installation of the NTRC fuel cell was funded by the Distributed Energy Program with partial funding from the Department of Defense's Climate Change Fuel Cell Buy Down Program, administered by the National Energy Technology Laboratory. On-going operational expenses are funded by ORNL's utility budget and are paid from operational cost savings. Technical information and the benefit-cost of the fuel cell are both evaluated in this report and sister reports.

  2. Synthesis of Non-blinking Semiconductor Quantum Dots Emitting...

    Office of Scientific and Technical Information (OSTI)

    37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ALIGNMENT; CADMIUM; EMISSION SPECTRA; FLUORESCENCE; QUANTUM DOTS; RECOMBINATION;...

  3. RKKY interaction in a chirally coupled double quantum dot system...

    Office of Scientific and Technical Information (OSTI)

    Subject: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHIRALITY; EXCHANGE INTERACTIONS; KONDO EFFECT; MAGNETIC FIELDS; QUANTUM DOTS; TEMPERATURE DEPENDENCE ...

  4. US Department of Transportation specification packages evaluation

    SciTech Connect (OSTI)

    Ratledge, J.E.; Rawl, R.R.

    1992-01-01

    Specification packages are broad families of package designs and approved by the Department of Transportation (DOT) for transport of certain classes of radioactive materials, with each specification containing a number of designs of various sizes. Many of the individual package designs are not supported by reasonably current safety analyses. The Nuclear Regulatory Commission (NRC) asked Oak Ridge National Laboratory (ORNL) staff to collect all related information, perform analyses, and identify alternative actions that will enable NRC and DOT to make informed decisions on whether to retain, withdraw, or modify the existing regulatory permission for the use of specification packages to transport radioactive and fissile materials. This paper presents the background, issues, and progress made in this activity.

  5. US Department of Transportation specification packages evaluation

    SciTech Connect (OSTI)

    Ratledge, J.E.; Rawl, R.R.

    1992-03-01

    Specification packages are broad families of package designs and approved by the Department of Transportation (DOT) for transport of certain classes of radioactive materials, with each specification containing a number of designs of various sizes. Many of the individual package designs are not supported by reasonably current safety analyses. The Nuclear Regulatory Commission (NRC) asked Oak Ridge National Laboratory (ORNL) staff to collect all related information, perform analyses, and identify alternative actions that will enable NRC and DOT to make informed decisions on whether to retain, withdraw, or modify the existing regulatory permission for the use of specification packages to transport radioactive and fissile materials. This paper presents the background, issues, and progress made in this activity.

  6. Exciton binding energy in semiconductor quantum dots

    SciTech Connect (OSTI)

    Pokutnii, S. I.

    2010-04-15

    In the adiabatic approximation in the context of the modified effective mass approach, in which the reduced exciton effective mass {mu} = {mu}(a) is a function of the radius a of the semiconductor quantum dot, an expression for the exciton binding energy E{sub ex}(a) in the quantum dot is derived. It is found that, in the CdSe and CdS quantum dots with the radii a comparable to the Bohr exciton radii a{sub ex}, the exciton binding energy E{sub ex}(a) is substantially (respectively, 7.4 and 4.5 times) higher than the exciton binding energy in the CdSe and CdS single crystals.

  7. Quantum Dot-Based Cell Motility Assay

    SciTech Connect (OSTI)

    Gu, Weiwei; Pellegrino, Teresa; Parak Wolfgang J; Boudreau,Rosanne; Le Gros, Mark A.; Gerion, Daniele; Alivisatos, A. Paul; Larabell, Carolyn A.

    2005-06-06

    Because of their favorable physical and photochemical properties, colloidal CdSe/ZnS-semiconductor nanocrystals (commonly known as quantum dots) have enormous potential for use in biological imaging. In this report, we present an assay that uses quantum dots as markers to quantify cell motility. Cells that are seeded onto a homogeneous layer of quantum dots engulf and absorb the nanocrystals and, as a consequence, leave behind a fluorescence-free trail. By subsequently determining the ratio of cell area to fluorescence-free track area, we show that it is possible to differentiate between invasive and noninvasive cancer cells. Because this assay uses simple fluorescence detection, requires no significant data processing, and can be used in live-cell studies, it has the potential to be a powerful new tool for discriminating between invasive and noninvasive cancer cell lines or for studying cell signaling events involved in migration.

  8. The Oak Ridge Field Research Center : Advancing Scientific Understanding of the Transportation, Fate, and Remediation of Subsurface Contamination Sources and Plumes

    SciTech Connect (OSTI)

    David Watson

    2005-04-18

    Historical research, development, and testing of nuclear materials across this country resulted in subsurface contamination that has been identified at over 7,000 discrete sites across the U.S. Department of Energy (DOE) complex. With the end of the Cold War threat, DOE has shifted its emphasis to remediation, decommissioning, and decontamination of the immense volumes of contaminated groundwater, sediments, and structures at its sites. DOE currently is responsible for remediating 1.7 trillion gallons of contaminated groundwater, an amount equal to approximately four times the daily U.S. water consumption, and 40 million cubic meters of contaminated soil, enough to fill approximately 17 professional sports stadiums.* DOE also sponsors research intended to improve or develop remediation technologies, especially for difficult, currently intractable contaminants or conditions. The Oak Ridge FRC is representative of some difficult sites, contaminants, and conditions. Buried wastes in contact with a shallow water table have created huge reservoirs of contamination. Rainfall patterns affect the water table level seasonally and over time. Further, the hydrogeology of the area, with its fractures and karst geology, affects the movement of contaminant plumes. Plumes have migrated long distances and to surface discharge points through ill-defined preferred flowpaths created by the fractures and karst conditions. From the standpoint of technical effectiveness, remediation options are limited, especially for contaminated groundwater. Moreover, current remediation practices for the source areas, such as capping, can affect coupled processes that, in turn, may affect the movement of subsurface contaminants in unknown ways. Research conducted at the FRC or with FRC samples therefore promotes understanding of the processes that influence the transport and fate of subsurface contaminants, the effectiveness and long-term consequences of extant remediation options, and the development of improved remediation strategies.

  9. Bilayer graphene quantum dot defined by topgates

    SciTech Connect (OSTI)

    Mller, Andr; Kaestner, Bernd; Hohls, Frank; Weimann, Thomas; Pierz, Klaus; Schumacher, Hans W., E-mail: hans.w.schumacher@ptb.de [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)

    2014-06-21

    We investigate the application of nanoscale topgates on exfoliated bilayer graphene to define quantum dot devices. At temperatures below 500 mK, the conductance underneath the grounded gates is suppressed, which we attribute to nearest neighbour hopping and strain-induced piezoelectric fields. The gate-layout can thus be used to define resistive regions by tuning into the corresponding temperature range. We use this method to define a quantum dot structure in bilayer graphene showing Coulomb blockade oscillations consistent with the gate layout.

  10. TEST & EVALUATION REPORT FOR THE HEDGEHOG-II PACKAGING SYSTEMS DOT-7A TYPE A CONTAINER

    SciTech Connect (OSTI)

    KELLY, D.L.

    2003-12-29

    This report documents the US. Department of Transportation Specification 7A (DOT-7A) Type A compliance test and evaluation results for the Hedgehog-II packaging systems. The approved Hedgehog-II packaging configurations provide primary and secondary containment. The approved packaging configurations described within this report are designed to ship Type A quantities of radioactive materials, normal form. Contents may be in solid or liquid form. Liquids transported in the approved 1 L glass bottle assembly shall have a specific gravity of less than or equal to 1.6. Liquids transported in all other approved configurations shall have a specific gravity of less than or equal to 2.0. The solid contents, including packaging, are limited in weight to the gross weight of the as-tested liquids and bottles. The approved Hedgehog-II packaging configurations described in this report may be transported by air, and have been evaluated as meeting the applicable International Air Transport Association/International Civil Aviation Organization (IATA/ICAO) Dangerous Goods Regulations in addition to the DOT requirements.

  11. Department of Transportation Pipeline and Hazardous Materials Safety Administration Activities

    Office of Environmental Management (EM)

    DOT/PHMSA A ti iti Activities Michael Conroy U S Department of Transportation - 1 - U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration Office of Hazardous Materials Safety Radioactive Materials U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration Overview * Harmonization with International Regulations * Update on Revisions to International Regulations * Recent Letters of Interpretation * Update on Rulemakings * PHMSA

  12. Energy Department Welcomes Department of Transportation as New Workplace

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

    Charging Challenge Partner | Department of Energy Welcomes Department of Transportation as New Workplace Charging Challenge Partner Energy Department Welcomes Department of Transportation as New Workplace Charging Challenge Partner November 17, 2015 - 11:28am Addthis Today, the Energy Department is welcoming the Department of Transportation (DOT) as a partner in its Workplace Charging Challenge, which aims to make workplace charging for plug-in electric vehicles available to employees across

  13. NREL: Transportation Research - Success Stories

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

    ... Fuel, Engine, and Infrastructure Co-Optimization NREL's in-depth exploration of the ... Red engine. Demo Projects Introduce New Class of Natural Gas Vehicles Graph illustrating ...

  14. NREL: Transportation Research - Fuels Performance

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

    Fuels Performance Photo of a man working with laboratory equipment. NREL fuel performance chemists evaluate a broad range of performance criteria, including storage stability....

  15. Location deterministic biosensing from quantum-dot-nanowire assemblies

    SciTech Connect (OSTI)

    Liu, Chao [Materials Science and Engineering Program, Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712 (United States); Kim, Kwanoh [Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Fan, D. L., E-mail: dfan@austin.utexas.edu [Materials Science and Engineering Program, Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712 (United States); Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-08-25

    Semiconductor quantum dots (QDs) with high fluorescent brightness, stability, and tunable sizes, have received considerable interest for imaging, sensing, and delivery of biomolecules. In this research, we demonstrate location deterministic biochemical detection from arrays of QD-nanowire hybrid assemblies. QDs with diameters less than 10?nm are manipulated and precisely positioned on the tips of the assembled Gold (Au) nanowires. The manipulation mechanisms are quantitatively understood as the synergetic effects of dielectrophoretic (DEP) and alternating current electroosmosis (ACEO) due to AC electric fields. The QD-nanowire hybrid sensors operate uniquely by concentrating bioanalytes to QDs on the tips of nanowires before detection, offering much enhanced efficiency and sensitivity, in addition to the position-predictable rationality. This research could result in advances in QD-based biomedical detection and inspires an innovative approach for fabricating various QD-based nanodevices.

  16. Kondo and mixed-valence regimes in multilevel quantum dots

    SciTech Connect (OSTI)

    Chudnovskiy, A. L.; Ulloa, S. E.

    2001-04-15

    We investigate the dependence of the ground state of a multilevel quantum dot on the coupling to an external fermionic system and on the interactions in the dot. As the coupling to the external system increases, the rearrangement of the effective energy levels in the dot signals the transition from the Kondo regime to a mixed-valence (MV) regime. The MV regime in a two-level dot is characterized by an intrinsic mixing of the levels in the dot, resulting in nonperturbative subtunneling and supertunneling phenomena that strongly influence the Kondo effect.

  17. Synthesis of CdSe quantum dots for quantum dot sensitized solar cell

    SciTech Connect (OSTI)

    Singh, Neetu Kapoor, Avinashi; Kumar, Vinod; Mehra, R. M.

    2014-04-24

    CdSe Quantum Dots (QDs) of size 0.85 nm were synthesized using chemical route. ZnO based Quantum Dot Sensitized Solar Cell (QDSSC) was fabricated using CdSe QDs as sensitizer. The Pre-synthesized QDs were found to be successfully adsorbed on front ZnO electrode and had potential to replace organic dyes in Dye Sensitized Solar Cells (DSSCs). The efficiency of QDSSC was obtained to be 2.06 % at AM 1.5.

  18. Geological Sequestration Training and Research Program in Capture and Transport: Development of the Most Economical Separation Method for CO2 Capture

    SciTech Connect (OSTI)

    Vahdat, Nader

    2013-09-30

    The project provided hands-on training and networking opportunities to undergraduate students in the area of carbon dioxide (CO2) capture and transport, through fundamental research study focused on advanced separation methods that can be applied to the capture of CO2 resulting from the combustion of fossil-fuels for power generation . The project teams approach to achieve its objectives was to leverage existing Carbon Capture and Storage (CCS) course materials and teaching methods to create and implement an annual CCS short course for the Tuskegee University community; conduct a survey of CO2 separation and capture methods; utilize data to verify and develop computer models for CO2 capture and build CCS networks and hands-on training experiences. The objectives accomplished as a result of this project were: (1) A comprehensive survey of CO2 capture methods was conducted and mathematical models were developed to compare the potential economics of the different methods based on the total cost per year per unit of CO2 avoidance; and (2) Training was provided to introduce the latest CO2 capture technologies and deployment issues to the university community.

  19. Transportation Safety Excellence in Operations Through Improved Transportation Safety Document

    SciTech Connect (OSTI)

    Dr. Michael A. Lehto; MAL

    2007-05-01

    A recent accomplishment of the Idaho National Laboratory (INL) Materials and Fuels Complex (MFC) Nuclear Safety analysis group was to obtain DOE-ID approval for the inter-facility transfer of greater-than-Hazard-Category-3 quantity radioactive/fissionable waste in Department of Transportation (DOT) Type A drums at MFC. This accomplishment supported excellence in operations through safety analysis by better integrating nuclear safety requirements with waste requirements in the Transportation Safety Document (TSD); reducing container and transport costs; and making facility operations more efficient. The MFC TSD governs and controls the inter-facility transfer of greater-than-Hazard-Category-3 radioactive and/or fissionable materials in non-DOT approved containers. Previously, the TSD did not include the capability to transfer payloads of greater-than-Hazard-Category-3 radioactive and/or fissionable materials using DOT Type A drums. Previous practice was to package the waste materials to less-than-Hazard-Category-3 quantities when loading DOT Type A drums for transfer out of facilities to reduce facility waste accumulations. This practice allowed operations to proceed, but resulted in drums being loaded to less than the Waste Isolation Pilot Plant (WIPP) waste acceptance criteria (WAC) waste limits, which was not cost effective or operations friendly. An improved and revised safety analysis was used to gain DOE-ID approval for adding this container configuration to the MFC TSD safety basis. In the process of obtaining approval of the revised safety basis, safety analysis practices were used effectively to directly support excellence in operations. Several factors contributed to the success of MFCs effort to obtain approval for the use of DOT Type A drums, including two practices that could help in future safety basis changes at other facilities. 1) The process of incorporating the DOT Type A drums into the TSD at MFC helped to better integrate nuclear safety requirements with waste requirements. MFCs efforts illustrate that utilizing the requirements of other disciplines, beyond nuclear safety, can provide an efficient process. Analyzing current processes to find better ways of meeting the requirements of multiple disciplines within a safety basis can lead to a more cost-effective, streamlined process. 2) Incorporating the DOT Type A drums into the MFC TSD was efficient because safety analysts utilized a transportation plan that provided analysis that could also be used for the change to the TSD addendum. In addition, because the plan they used had already been approved and was in use by the Idaho Cleanup Project (ICP) at the INL, justification for the change to the TSD was more compelling. MFC safety analysts proved that streamlining a process can be made more feasible by drawing from analysis that has already been completed.

  20. Tunable Quantum Dot Solids: Impact of Interparticle Interactions on Bulk Properties

    SciTech Connect (OSTI)

    Sinclair, Michael B.; Fan, Hongyou; Brener, Igal; Liu, Sheng; Luk, Ting S.; Li, Binsong

    2015-09-01

    QD-solids comprising self-assembled semiconductor nanocrystals such as CdSe are currently under investigation for use in a wide array of applications including light emitting diodes, solar cells, field effect transistors, photodetectors, and biosensors. The goal of this LDRD project was develop a fundamental understanding of the relationship between nanoparticle interactions and the different regimes of charge and energy transport in semiconductor quantum dot (QD) solids. Interparticle spacing was tuned through the application of hydrostatic pressure in a diamond anvil cell, and the impact on interparticle interactions was probed using x-ray scattering and a variety of static and transient optical spectroscopies. During the course of this LDRD, we discovered a new, previously unknown, route to synthesize semiconductor quantum wires using high pressure sintering of self-assembled quantum dot crystals. We believe that this new, pressure driven synthesis approach holds great potential as a new tool for nanomaterials synthesis and engineering.

  1. Copenhagen Accord NAMA Submissions Implications for the Transport...

    Open Energy Info (EERE)

    Organization: GTZ, Institute for Transportation and Development Policy (ITDP), Transport Research Laboratory(TRL), International Association for Public Transport (UITP), Veolia...

  2. Research Highlight

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

    Area of Research: Cloud Processes Working Group(s): Cloud Life Cycle Journal Reference: Wong M, M Ovchinnikov, and M Wang. 2015. "Evaluation of subgrid-scale hydrometeor transport...

  3. NREL: Biomass Research - Facilities

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

    Facilities At NREL's state-of-the-art biomass research facilities, researchers design and optimize processes to convert renewable biomass feedstocks into transportation fuels and...

  4. Proposed mechanism to represent the suppression of dark current density by four orders with low energy light ion (H{sup ?}) implantation in quaternary alloy-capped InAs/GaAs quantum dot infrared photodetectors

    SciTech Connect (OSTI)

    Mandal, A.; Ghadi, H.; Mathur, K.L.; Basu, A.; Subrahmanyam, N.B.V.; Singh, P.; Chakrabarti, S.

    2013-08-01

    Graphical abstract: - Abstract: Here we propose a carrier transport mechanism for low energy H{sup ?} ions implanted InAs/GaAs quantum dot infrared photodetectors supportive of the experimental results obtained. Dark current density suppression of up to four orders was observed in the implanted quantum dot infrared photodetectors, which further demonstrates that they are effectively operational. We concentrated on determining how defect-related material and structural changes attributed to implantation helped in dark current density reduction for InAs/GaAs quantum dot infrared photodetectors. This is the first study to report the electrical carrier transport mechanism of H{sup ?} ion-implanted InAs/GaAs quantum dot infrared photodetectors.

  5. Theoretical performance of solar cell based on mini-bands quantum dots

    SciTech Connect (OSTI)

    Aly, Abou El-Maaty M. E-mail: ashraf.nasr@gmail.com; Nasr, A. E-mail: ashraf.nasr@gmail.com

    2014-03-21

    The tremendous amount of research in solar energy is directed toward intermediate band solar cell for its advantages compared with the conventional solar cell. The latter has lower efficiency because the photons have lower energy than the bandgap energy and cannot excite mobile carriers from the valence band to the conduction band. On the other hand, if mini intermediate band is introduced between the valence and conduction bands, then the smaller energy photons can be used to promote charge carriers transfer to the conduction band and thereby the total current increases while maintaining a large open circuit voltage. In this article, the influence of the new band on the power conversion efficiency for structure of quantum dots intermediate band solar cell is theoretically investigated and studied. The time-independent Schrdinger equation is used to determine the optimum width and location of the intermediate band. Accordingly, achievement of a maximum efficiency by changing the width of quantum dots and barrier distances is studied. Theoretical determination of the power conversion efficiency under the two different ranges of QD width is presented. From the obtained results, the maximum power conversion efficiency is about 70.42%. It is carried out for simple cubic quantum dot crystal under fully concentrated light. It is strongly dependent on the width of quantum dots and barrier distances.

  6. Radiation Transport

    SciTech Connect (OSTI)

    Urbatsch, Todd James

    2015-06-15

    We present an overview of radiation transport, covering terminology, blackbody raditation, opacities, Boltzmann transport theory, approximations to the transport equation. Next we introduce several transport methods. We present a section on Caseology, observing transport boundary layers. We briefly broach topics of software development, including verification and validation, and we close with a section on high energy-density experiments that highlight and support radiation transport.

  7. The operation mechanism of poly(9,9-dioctylfluorenyl-2,7-diyl) dots in high efficiency polymer solar cells

    SciTech Connect (OSTI)

    Liu, Chunyu; He, Yeyuan; Zhang, Xinyuan; Li, Zhiqi; Li, Jinfeng; Zhang, Zhihui; Guo, Wenbin Ruan, Shengping; Shen, Liang

    2015-05-11

    The highly efficient polymer solar cells were realized by doping poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) dots into active layer. The dependence of doping amount on devices performance was investigated and a high efficiency of 7.15% was obtained at an optimal concentration, accounting for a 22.4% enhancement. The incorporation of PFO dots (Pdots) is conducted to the improvement of J{sub sc} and fill factor mainly due to the enhancement of light absorption and charge transport property. Pdots blended in active layer provides an interface for charge transfer and enables the formation of percolation pathways for electron transport. The introduction of Pdots was proven an effective way to improve optical and electrical properties of solar cells.

  8. Controlling quantum dot energies using submonolayer bandstructure engineering

    SciTech Connect (OSTI)

    Yu, L.; Law, S.; Wasserman, D.; Jung, D.; Lee, M. L.; Shen, J.; Cha, J. J.

    2014-08-25

    We demonstrate control of energy states in epitaxially-grown quantum dot structures formed by stacked submonolayer InAs depositions via engineering of the internal bandstructure of the dots. Transmission electron microscopy of the stacked sub-monolayer regions shows compositional inhomogeneity, indicative of the presence of quantum dots. The quantum dot ground state is manipulated not only by the number of deposited InAs layers, but also by control of the thickness and material composition of the spacing layers between submonolayer InAs depositions. In this manner, we demonstrate the ability to shift the quantum dot ground state energy at 77?K from 1.38?eV to 1.88?eV. The results presented offer a potential avenue towards enhanced control of dot energies for a variety of optoelectronic applications.

  9. Safety-analysis report for packaging - corrugated steel container (SAND Box) for DOT specification 7A packaging

    SciTech Connect (OSTI)

    Brugger, R.P.

    1983-05-16

    Department of Transportation (DOT) Specification 7A, Type A corrugated steel containers for shipment and storage of Transuranic (TRU) solid waste have been developed. The containers are made entirely of 14 gauge (0.0747-in.) low carbon steel. All seams including the closure are welded to produce a leak-tight container. Four sizes of the SAND Box container have successfully met all Specification 7A, Type A requirements.

  10. Safety analysis report for packaging-corrugated steel container (SAND Box) for DOT Specification 7A packaging

    SciTech Connect (OSTI)

    Brugger, R.P.

    1983-01-24

    Department of Transportation (DOT) Specification 7A, Type A corrugated steel containers for shipment and storage of Transuranic (TRU) solid waste have been developed. The containers are made entirely of 14 gauge (0.0747-in.) low carbon steel. All seams including the closure are welded to produce a leaktight container. Four sizes of the SAND Box container have successfully met all Specification 7A, Type A requirements.

  11. Interdot Coulomb correlation effects and spin-orbit coupling in two carbon nanotube quantum dots

    SciTech Connect (OSTI)

    Wang, Zhen-Hua; Kuang, Xiao-Yu Zhong, Ming-Min; Shao, Peng; Li, Hui

    2014-01-28

    Transport properties of the two-level Kondo effect involving spin, orbital, and pseudospin degrees of freedom are examined in a parallel carbon nanotube double quantum dot with a sufficient interdot Coulomb interaction and small interdot tunneling. The interdot Coulomb correlation effects are taken into account, and it plays an important role in forming bonding and antibonding states. Attached to ferromagnetic leads, the Kondo effect is observed at the interdot Coulomb blockade region with degeneracy of spin, orbital, and pseudospin degrees of freedom. A crossover from a two-level Kondo state involving the fivefold degeneracy of the double quantum dots to an SU(4) spin-orbit Kondo state and to an SU(2) spin-Kondo effect is demonstrated. At finite magnetic field, the splitting of the spin, orbital, and pseudospin Kondo resonance can be restored. For finite intradot Coulomb interaction U, there is a competition between the single-dot Kondo effect and the antiferromagnetic exchange coupling J{sub AFM}, resulting in the suppression of the Kondo resonance. Moreover, both the J{sub AFM} and the Zeeman interactions compete, leading to need a much higher value of the magnetic field to compensate for the Kondo splitting.

  12. Mastermind Session: Connecting the Dots Between the Real Estate...

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

    the Dots Between the Real Estate Market and Residential Energy Efficiency Featuring Host Rich Dooley, Arlington County, VA, Call Slides and Discussion Summary, August 14, 2014. ...

  13. Tuning Into the Right Wavelength: Quantum Dot Rainbow Increases...

    Office of Science (SC) Website

    Sequentially deposited green, orange, and red-emitting quantum dots serve as sensitizers ... converted more light than expected into energy compared with solar cells containing only ...

  14. Kondo time scales for quantum dots: Response to pulsed bias potentials

    SciTech Connect (OSTI)

    Plihal, Martin; Langreth, David C.; Nordlander, Peter

    2000-05-15

    The response of a quantum dot in the Kondo regime to rectangular pulsed bias potentials of various strengths and durations is studied theoretically. It is found that the rise time is faster than the fall time, and also faster than time scales normally associated with the Kondo problem. For larger values of the pulsed bias, one can induce dramatic oscillations in the induced current with a frequency approximating the splitting between the Kondo peaks that would be present in steady state. The effect persists in the total charge transported per pulse, which should facilitate the experimental observation of the phenomenon. (c) 2000 The American Physical Society.

  15. Status report on the Small Secure Transportable Autonomous Reactor (SSTAR) /Lead-cooled Fast Reactor (LFR) and supporting research and development.

    SciTech Connect (OSTI)

    Sienicki, J. J.; Moisseytsev, A.; Yang, W. S.; Wade, D. C.; Nikiforova, A.; Hanania, P.; Ryu, H. J.; Kulesza, K. P.; Kim, S. J.; Halsey, W. G.; Smith, C. F.; Brown, N. W.; Greenspan, E.; de Caro, M.; Li, N.; Hosemann, P.; Zhang, J.; Yu, H.; Nuclear Engineering Division; LLNL; LANL; Massachusetts Inst. of Tech.; Ecole des Mines de Paris; Oregon State Univ.; Univ.of California at Berkley

    2008-06-23

    This report provides an update on development of a pre-conceptual design for the Small Secure Transportable Autonomous Reactor (SSTAR) Lead-Cooled Fast Reactor (LFR) plant concept and supporting research and development activities. SSTAR is a small, 20 MWe (45 MWt), natural circulation, fast reactor plant for international deployment concept incorporating proliferation resistance for deployment in non-fuel cycle states and developing nations, fissile self-sufficiency for efficient utilization of uranium resources, autonomous load following making it suitable for small or immature grid applications, and a high degree of passive safety further supporting deployment in developing nations. In FY 2006, improvements have been made at ANL to the pre-conceptual design of both the reactor system and the energy converter which incorporates a supercritical carbon dioxide Brayton cycle providing higher plant efficiency (44 %) and improved economic competitiveness. The supercritical CO2 Brayton cycle technology is also applicable to Sodium-Cooled Fast Reactors providing the same benefits. One key accomplishment has been the development of a control strategy for automatic control of the supercritical CO2 Brayton cycle in principle enabling autonomous load following over the full power range between nominal and essentially zero power. Under autonomous load following operation, the reactor core power adjusts itself to equal the heat removal from the reactor system to the power converter through the large reactivity feedback of the fast spectrum core without the need for motion of control rods, while the automatic control of the power converter matches the heat removal from the reactor to the grid load. The report includes early calculations for an international benchmarking problem for a LBE-cooled, nitride-fueled fast reactor core organized by the IAEA as part of a Coordinated Research Project on Small Reactors without Onsite Refueling; the calculations use the same neutronics computer codes and methodologies applied to SSTAR. Another section of the report details the SSTAR safety design approach which is based upon defense-in-depth providing multiple levels of protection against the release of radioactive materials and how the inherent safety features of the lead coolant, nitride fuel, fast neutron spectrum core, pool vessel configuration, natural circulation, and containment meet or exceed the requirements for each level of protection. The report also includes recent results of a systematic analysis by LANL of data on corrosion of candidate cladding and structural material alloys of interest to SSTAR by LBE and Pb coolants; the data were taken from a new database on corrosion by liquid metal coolants created at LANL. The analysis methodology that considers penetration of an oxidation front into the alloy and dissolution of the trailing edge of the oxide into the coolant enables the long-term corrosion rate to be extracted from shorter-term corrosion data thereby enabling an evaluation of alloy performance over long core lifetimes (e.g., 30 years) that has heretofore not been possible. A number of candidate alloy specimens with special treatments or coatings which might enhance corrosion resistance at the temperatures at which SSTAR would operate were analyzed following testing in the DELTA loop at LANL including steels that were treated by laser peening at LLNL; laser peening is an approach that alters the oxide-metal bonds which could potentially improve corrosion resistance. LLNL is also carrying out Multi-Scale Modeling of the Fe-Cr system with the goal of assisting in the development of cladding and structural materials having greater resistance to irradiation.

  16. First AEO2014 Transportation Working Group Meeting Summary

    Gasoline and Diesel Fuel Update (EIA)

    1, 2013 MEMORANDUM FOR: JOHN CONTI ASSISTANT ADMINISTRATOR FOR ENERGY ANALYSIS PAUL HOLTBERG TEAM LEADER ANALYSIS INTEGRATION TEAM JIM TURNURE DIRECTOR OFFICE OF ENERGY CONSUMPTION AND EFFICIENCY ANALYSIS FROM: TRANSPORTATION CONSUMPTION & EFFICIENCY ANALYSIS TEAM SUBJECT: First AEO2014 Transportation Working Group Meeting Summary (presented on 07-23-2013) Attendees: Shirley Neff (EIA/AO) Jim Turnure (EIA/OECEA) Jade Jenkins (EIA/OECEA) Ken Katz (DOT/NHTSA) Pete Whitman (DOE/PI) Tien Nguyen

  17. Applicability of the {bold k}{center_dot}{bold p} method to the electronic structure of quantum dots

    SciTech Connect (OSTI)

    Fu, H.; Wang, L.; Zunger, A.

    1998-04-01

    The {bold k}{center_dot}{bold p} method has become the {open_quotes}standard model{close_quotes} for describing the electronic structure of nanometer-size quantum dots. In this paper we perform parallel {bold k}{center_dot}{bold p} (6{times}6 and 8{times}8) and direct-diagonalization pseudopotential studies on spherical quantum dots of an ionic material{emdash}CdSe, and a covalent material{emdash}InP. By using an equivalent input in both approaches, i.e., starting from a given atomic pseudopotential and deriving from it the Luttinger parameters in {bold k}{center_dot}{bold p} calculation, we investigate the effect of the different underlying wave-function representations used in {bold k}{center_dot}{bold p} and in the more exact pseudopotential direct diagonalization. We find that (i) the 6{times}6{bold k}{center_dot}{bold p} envelope function has a distinct (odd or even) parity, while atomistic wave function is parity-mixed. The 6{times}6{bold k}{center_dot}{bold p} approach produces an incorrect order of the highest valence states for both InP and CdSe dots: the p-like level is above the s-like level. (ii) It fails to reveal that the second conduction state in small InP dots is folded from the L point in the Brillouin zone. Instead, all states in {bold k}{center_dot}{bold p} are described as {Gamma}-like. (iii) The {bold k}{center_dot}{bold p} overestimates the confinement energies of both valence states and conduction states. A wave-function projection analysis shows that the principal reasons for these {bold k}{center_dot}{bold p} errors in dots are (a) use of restricted basis set, and (b) incorrect {ital bulk} dispersion relation. Error (a) can be reduced only by increasing the number of basis functions. Error (b) can be reduced by altering the {bold k}{center_dot}{bold p} implementation so as to bend upwards the second lowest bulk band, and to couple the conduction band into the s-like dot valence state. Our direct diagonalization approach provides an accurate and practical replacement to the standard model in that it is rather general, and can be performed simply on a standard workstation. {copyright} {ital 1998} {ital The American Physical Society}

  18. GE Global Research Careers | GE Global Research

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

    Finding solutions in energy, health and home, transportation and finance. Building, ... path at GE Global Research guides scientists' and engineers' individual development. ...

  19. ISSUES ASSOCIATED WITH SAFE PACKAGING AND TRANSPORT OF NANOPARTICLES

    SciTech Connect (OSTI)

    Gupta, N.; Smith, A.

    2011-02-14

    Nanoparticles have long been recognized a hazardous substances by personnel working in the field. They are not, however, listed as a separate, distinct category of dangerous goods at present. As dangerous goods or hazardous substances, they require packaging and transportation practices which parallel the established practices for hazardous materials transport. Pending establishment of a distinct category for such materials by the Department of Transportation, existing consensus or industrial protocols must be followed. Action by DOT to establish appropriate packaging and transport requirements is recommended.

  20. Going the Distance? NRC's Response to the National Academy of Science's Transportation Study

    SciTech Connect (OSTI)

    Easton, E.P.; Bajwa, C.S.

    2008-07-01

    In February 2006, the National Academy of Sciences (NAS) published the results of a 3 1/2-year study, titled Going the Distance, that examined the safety of transporting spent nuclear fuel (SNF) and high level waste (HLW) in the United States. NAS initiated this study to address what it perceived to be a national need for an independent, objective, and authoritative analysis of SNF and HLW transport in the United States. The study was co-sponsored by the U.S. Nuclear Regulatory Commission (NRC), the U.S. Department of Energy (DOE), the U.S. Department of Transportation (DOT), the Electric Power Research Institute and the National Cooperative Highway Research Program. This paper addresses some of the recommendations made in the NAS study related to the performance of SNF transportation casks in long duration fires, the use of full-scale package testing, and the need for an independent review of transportation security prior to the commencement of large scale shipping campaigns to an interim storage site or geologic repository. In conclusion: The NRC believes that the current regulations in 10 CFR Part 71 for the design of SNF and HLW transportation packages provide a very high level of protection to the public for very severe accidents and credible threat scenarios. As recommended by the NAS study, additional studies of accidents involving severe fires have been completed. These studies have confirmed that spent fuel casks would be expected to withstand very severe fires without the release of any fission products from the spent fuel. Additionally, changes in rail operating procedures such as the use of dedicated trains and prohibition on the co-location of SNF and flammable liquids in rail tunnels can further reduce the already low probability of severe rail accident fires involving SNF and HLW. (authors)

  1. Research Highlight

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

    Arctic Haze: Effect of Anthropogenic and Biomass Burning Aerosols Transported from Europe to the Arctic Download a printable PDF Submitter: Fast, J. ., Pacific Northwest National Laboratory Area of Research: Aerosol Properties Working Group(s): Cloud-Aerosol-Precipitation Interactions Journal Reference: Marelle L, J Raut, JL Thomas, KS Law, B Quennehen, G Ancellet, J Pelon, A Schwarzenboeck, and JD Fast. 2015. "Transport of anthropogenic and biomass burning aerosols from Europe to the

  2. Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous

    Office of Scientific and Technical Information (OSTI)

    optical imaging, photothermal effect and thermometry (Journal Article) | SciTech Connect Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous optical imaging, photothermal effect and thermometry Citation Details In-Document Search Title: Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous optical imaging, photothermal effect and thermometry Hybrid semiconductor-metal nanoscale constructs are of both fundamental and practical interest.

  3. Beam Transport

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

    Beam Transport Beam Transport A simplified drawing of the beam transport system from the linac to Target-1 (Lujan Center), Target-2 (Blue Room) and Target-4 is shown below. In usual operation beam is transported from the linac through the pulsed Ring Injection Kicker (RIKI) magnet. When RIKI is switched on, the beam is injected into the storage ring with the time structure shown here. The beam is accumulated in the PSR and then transported to Target-1. beam_transport1 Simplified drawing of the

  4. Kondo effect in coupled quantum dots under magnetic fields

    SciTech Connect (OSTI)

    Aono, Tomosuke; Eto, Mikio

    2001-08-15

    The Kondo effect in coupled quantum dots is investigated theoretically under magnetic fields. We show that the magnetoconductance (MC) illustrates the peak structures of Kondo resonant spectra. When the dot-dot tunneling coupling V{sub C} is smaller than the dot-lead coupling {Delta} (level broadening), Kondo resonant levels appear at the Fermi level (E{sub F}). The Zeeman splitting of the levels weakens the Kondo effect, which results in a negative MC. When V{sub C} is larger than {Delta}, the Kondo resonances form bonding and antibonding levels, located below and above E{sub F}, respectively. We observe a positive MC since the Zeeman splitting increases the overlap between the levels at E{sub F}. In the presence of antiferromagnetic spin coupling between the dots, the sign of the MC can change as a function of the gate voltage.

  5. Approaches to Future Generation Photovoltaics and Solar Fuels: Multiple Exciton Generation in Quantum Dots, Quantum Dot Arrays, Molecular Singlet Fission, and Quantum Dot Solar Cells

    SciTech Connect (OSTI)

    Nozik, A. J.; Beard, M. C.; Johnson, J. C.; Hanna, M. C.; Luther, J. M.; Midgett, A.; Semonin, O.; Michel, J.

    2012-01-01

    One potential, long-term approach to more efficient future generation solar cells is to utilize the unique properties of quantum dots (QDs) and unique molecular chromophores to control the relaxation pathways of excited states to produce enhanced conversion efficiency through efficient multiple electron-hole pair generation from single photons . We have observed efficient multiple exciton generation (MEG) in PbSe, PbS, PbTe, and Si QDs and efficient singlet fission (SF) in molecules that satisfy specific requirements for their excited state energy level structure to achieve carrier multiplication. We have studied MEG in close-packed QD arrays where the QDs are electronically coupled in the films and thus exhibit good transport while still maintaining quantization and MEG. We have developed simple, all-inorganic QD solar cells that produce large short-circuit photocurrents and power conversion efficiencies in the 3-5% range via both nanocrystalline Schottky junctions and nanocrystalline p-n junctions. These solar cells also show QYs for photocurrent that exceed 100% in the photon energy regions where MEG is possible; the photocurrent MEG QYs as a function of photon energy match those determined via time-resolved spectroscopy. We have also observed very efficient SF in thin films of molecular crystals of 1,3 diphenylisobenzofuran with quantum yields of 200% at the optimum SF threshold of 2Eg (HOMO-LUMO for S{sub 0}-S{sub 1}), reflecting the creation of two excited triplet states from the first excited singlet state. Various possible configurations for novel solar cells based on MEG in QDs and SF in molecules that could produce high conversion efficiencies will be presented, along with progress in developing such new types of solar cells. Recent analyses of the effect of MEG or SF combined with solar concentration on the conversion efficiency of solar cells will be discussed.

  6. Competing interactions in semiconductor quantum dots

    SciTech Connect (OSTI)

    van den Berg, R.; Brandino, G. P.; El Araby, O.; Konik, R. M.; Gritsev, V.; Caux, J. -S.

    2014-10-01

    We introduce an integrability-based method enabling the study of semiconductor quantum dot models incorporating both the full hyperfine interaction as well as a mean-field treatment of dipole-dipole interactions in the nuclear spin bath. By performing free induction decay and spin echo simulations we characterize the combined effect of both types of interactions on the decoherence of the electron spin, for external fields ranging from low to high values. We show that for spin echo simulations the hyperfine interaction is the dominant source of decoherence at short times for low fields, and competes with the dipole-dipole interactions at longer times. On the contrary, at high fields the main source of decay is due to the dipole-dipole interactions. In the latter regime an asymmetry in the echo is observed. Furthermore, the non-decaying fraction previously observed for zero field free induction decay simulations in quantum dots with only hyperfine interactions, is destroyed for longer times by the mean-field treatment of the dipolar interactions.

  7. Competing interactions in semiconductor quantum dots

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

    van den Berg, R.; Brandino, G. P.; El Araby, O.; Konik, R. M.; Gritsev, V.; Caux, J. -S.

    2014-10-14

    In this study, we introduce an integrability-based method enabling the study of semiconductor quantum dot models incorporating both the full hyperfine interaction as well as a mean-field treatment of dipole-dipole interactions in the nuclear spin bath. By performing free induction decay and spin echo simulations we characterize the combined effect of both types of interactions on the decoherence of the electron spin, for external fields ranging from low to high values. We show that for spin echo simulations the hyperfine interaction is the dominant source of decoherence at short times for low fields, and competes with the dipole-dipole interactions atmore » longer times. On the contrary, at high fields the main source of decay is due to the dipole-dipole interactions. In the latter regime an asymmetry in the echo is observed. Furthermore, the non-decaying fraction previously observed for zero field free induction decay simulations in quantum dots with only hyperfine interactions, is destroyed for longer times by the mean-field treatment of the dipolar interactions.« less

  8. WIPP Transportation

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

    Transuranic Waste Transportation Container Documents Documents related to transuranic waste containers and packages. CBFO Tribal Program Information about WIPP shipments across tribal lands. Transportation Centralized Procurement Program - The Centralized Procurement Program provides a common method to procure standard items used in the packaging and handling of transuranic wasted destined for WIPP. Transuranic Waste Transportation Routes - A map showing transuranic waste generator sites and

  9. Transportation Fuel Supply | NISAC

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

    SheetsTransportation Fuel Supply content top Transportation Fuel Supply

  10. Safety analysis report for packaging a DOT 7A specification container for tritiated liquid wastes

    SciTech Connect (OSTI)

    Alford, E.

    1980-08-01

    This Safety Analysis Report for Packaging (SARP) was prepared in accordance with ERDA (DOE) Appendix 5201 for DOE/ALO review and approval of packaging of tritiated liquid wastes to be shipped from Sandia National Laboratories, Livermore, (SNLL) California. This report presents information pertinent to the construction of tritiated liquid waste shipping containers. It contains design and development considerations, explains tests and evaluations required to prove the container can withstand normal transportation conditions, and demonstrates that the Sandia container-and-radioactive-material shipment package is in compliance with DOE and Department of Transportation (DOT) safety requirements. An internal review of this SARP has been performed in compliance with the ERDA (DOE) Manual, 5201 Appendix V.

  11. Carrier multiplication detected through transient photocurrent in device-grade films of lead selenide quantum dots

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

    Gao, Jianbo; Fidler, Andrew F.; Klimov, Victor I.

    2015-09-08

    In carrier multiplication, the absorption of a single photon results in two or more electron–hole pairs. Quantum dots are promising materials for implementing carrier multiplication principles in real-life technologies. So far, however, most of research in this area has focused on optical studies of solution samples with yet to be proven relevance to practical devices. We report ultra-fast electro-optical studies of device-grade films of electronically coupled quantum dots that allow us to observe multiplication directly in the photocurrent. Our studies help rationalize previous results from both optical spectroscopy and steady-state photocurrent measurements and also provide new insights into effects ofmore » electric field and ligand treatments on multiexciton yields. Importantly, we demonstrate that using appropriate chemical treatments of the films, extra charges produced by carrier multiplication can be extracted from the quantum dots before they are lost to Auger recombination and hence can contribute to photocurrent of practical devices.« less

  12. NREL: Biomass Research - Capabilities

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

    is then separated, purified, and recovered for use as a transportation fuel. NREL biomass researchers and scientists have strong capabilities in many facets of biomass...

  13. Generation of even harmonics in coupled quantum dots

    SciTech Connect (OSTI)

    Guo Shifang; Duan Suqing; Yang Ning; Chu Weidong; Zhang Wei

    2011-07-15

    Using the spatial-temporal symmetry principle we developed recently, we propose an effective scheme for even-harmonics generation in coupled quantum dots. The relative intensity of odd and even harmonic components in the emission spectrum can be controlled by tuning the dipole couplings among the dots, which can be realized in experiments by careful design of the nanostructures. In particular, pure 2nth harmonics and (2n+1)th harmonics (where n is an integer) can be generated simultaneously with polarizations in two mutual perpendicular directions in our systems. An experimental design of the coupled dots system is presented.

  14. Zeno-logic applications of semiconductor quantum dots

    SciTech Connect (OSTI)

    Schneebeli, L.; Peyghambarian, N.; Feldtmann, T.; Kira, M.; Koch, S. W.

    2010-05-15

    Microscopic calculations show that CdSe-based semiconductor quantum dots with confined exciton and biexciton states are suitable candidates for Zeno-logic applications. The frequencies of the control and signal fields are chosen to guarantee very high transmission of the individual beams. If both fields are present simultaneously, they are strongly absorbed due to efficient ground-state-to-biexciton transitions. The optical Bloch equations for a three-level quantum-dot model with self-consistent light-matter coupling are solved numerically. The influence of dephasing and/or inhomogeneous dot distributions is analyzed and the conditions for satisfactory device operation are identified.

  15. Quantum Dot Tracers for Use in Engineered Geothermal | Department of Energy

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

    Quantum Dot Tracers for Use in Engineered Geothermal Quantum Dot Tracers for Use in Engineered Geothermal Quantum Dot Tracers for Use in Engineered Geothermal presentation at the April 2013 peer review meeting held in Denver, Colorado. PDF icon quantum_dot_tracers_peer2013.pdf More Documents & Publications Tracer Methods for Characterizing Fracture Stimulation in Engineered Geothermal Systems (EGS) Quantum Dot Tracers for Use in Engineered Geothermal Systems Use of Tracers to Characterize

  16. Electron states in semiconductor quantum dots

    SciTech Connect (OSTI)

    Dhayal, Suman S.; Ramaniah, Lavanya M.; Ruda, Harry E.; Nair, Selvakumar V.

    2014-11-28

    In this work, the electronic structures of quantum dots (QDs) of nine direct band gap semiconductor materials belonging to the group II-VI and III-V families are investigated, within the empirical tight-binding framework, in the effective bond orbital model. This methodology is shown to accurately describe these systems, yielding, at the same time, qualitative insights into their electronic properties. Various features of the bulk band structure such as band-gaps, band curvature, and band widths around symmetry points affect the quantum confinement of electrons and holes. These effects are identified and quantified. A comparison with experimental data yields good agreement with the calculations. These theoretical results would help quantify the optical response of QDs of these materials and provide useful input for applications.

  17. Greening Transportation

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

    Transportation Goal 2: Greening Transportation LANL supports and encourages employees to reduce their personal greenhouse gas emissions by offering various commuting and work schedule options. Our goal is to reduce emissions related to employee travel and commuting to and from work by 13 percent. Energy Conservation» Efficient Water Use & Management» High Performance Sustainable Buildings» Greening Transportation» Green Purchasing & Green Technology» Pollution Prevention» Science

  18. Transportation Energy

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

    - Transportation Energyadmin2015-05-14T22:34:50+00:00 Transportation Energy The national-level objective for the future is to create a carbon-neutral fleet that is powered by low-carbon US sources. Sandia delivers advanced technologies and design tools to the broad transportation sector in the following areas: Predictive Simulation of Engines Fuel sprays and their transition from the liquid to gas phase and computationally tractable models that capture the physics of combustion. Convergence of

  19. Sustainable Transportation

    SciTech Connect (OSTI)

    2012-09-01

    This document highlights DOE's Office of Energy Efficiency and Renewable Energy's advancements in transportation technologies, alternative fuels, and fuel cell technologies.

  20. Quantum Dot Tracers for Use in Engineered Geothermal Systems

    Broader source: Energy.gov [DOE]

    DOE Geothermal Peer Review 2010 - Presentation. Project objective: To develop and demonstrate a new class of tracers„semiconductor nanoparticles(quantum dots)„that offer great promise for use in characterizing fracture networks in EGS reservoirs.

  1. Quantum dot conjugates in a sub-micrometer fluidic channel

    DOE Patents [OSTI]

    Stavis, Samuel M. (Ithaca, NY); Edel, Joshua B. (Brookline, MA); Samiee, Kevan T. (Ithaca, NY); Craighead, Harold G. (Ithaca, NY)

    2008-07-29

    A nanofluidic channel fabricated in fused silica with an approximately 500 nm square cross section was used to isolate, detect and identify individual quantum dot conjugates. The channel enables the rapid detection of every fluorescent entity in solution. A laser of selected wavelength was used to excite multiple species of quantum dots and organic molecules, and the emission spectra were resolved without significant signal rejection. Quantum dots were then conjugated with organic molecules and detected to demonstrate efficient multicolor detection. PCH was used to analyze coincident detection and to characterize the degree of binding. The use of a small fluidic channel to detect quantum dots as fluorescent labels was shown to be an efficient technique for multiplexed single molecule studies. Detection of single molecule binding events has a variety of applications including high throughput immunoassays.

  2. Quantum dot conjugates in a sub-micrometer fluidic channel

    DOE Patents [OSTI]

    Stavis, Samuel M.; Edel, Joshua B.; Samiee, Kevan T.; Craighead, Harold G.

    2010-04-13

    A nanofluidic channel fabricated in fused silica with an approximately 500 nm square cross section was used to isolate, detect and identify individual quantum dot conjugates. The channel enables the rapid detection of every fluorescent entity in solution. A laser of selected wavelength was used to excite multiple species of quantum dots and organic molecules, and the emission spectra were resolved without significant signal rejection. Quantum dots were then conjugated with organic molecules and detected to demonstrate efficient multicolor detection. PCH was used to analyze coincident detection and to characterize the degree of binding. The use of a small fluidic channel to detect quantum dots as fluorescent labels was shown to be an efficient technique for multiplexed single molecule studies. Detection of single molecule binding events has a variety of applications including high throughput immunoassays.

  3. Synthesis of Non-blinking Semiconductor Quantum Dots Emitting...

    Office of Scientific and Technical Information (OSTI)

    Our previous work demonstrates that Quasi-Type II CdSeCdS core-shell quantum dots with ... synthesized to reduce cadmium exposure for applications in the biological environment. ...

  4. Comparison of quantum confinement effects between quantum wires and dots

    SciTech Connect (OSTI)

    Li, Jingbo; Wang, Lin-Wang

    2004-03-30

    Dimensionality is an important factor to govern the electronic structures of semiconductor nanocrystals. The quantum confinement energies in one-dimensional quantum wires and zero-dimensional quantum dots are quite different. Using large-scale first-principles calculations, we systematically study the electronic structures of semiconductor (including group IV, III-V, and II-VI) surface-passivated quantum wires and dots. The band-gap energies of quantum wires and dots have the same scaling with diameter for a given material. The ratio of band-gap-increases between quantum wires and dots is material-dependent, and slightly deviates from 0.586 predicted by effective-mass approximation. Highly linear polarization of photoluminescence in quantum wires is found. The degree of polarization decreases with the increasing temperature and size.

  5. Plasmonic giant quantum dots: Hybrid nanostructures for truly...

    Office of Scientific and Technical Information (OSTI)

    We show here that photostable 'giant' quantum dots when placed at the center of an ultrathin gold shell retain their key optical property of bright and blinking-free ...

  6. TxDOT Access Management Manual | Open Energy Information

    Open Energy Info (EERE)

    Access Management Manual Jump to: navigation, search OpenEI Reference LibraryAdd to library Legal Document- OtherOther: TxDOT Access Management ManualLegal Abstract Manual prepared...

  7. Deformation potentials of CdSe quantum dots

    SciTech Connect (OSTI)

    Li, Jingbo; Wang, Lin-Wang

    2004-06-02

    The size dependent deformation potentials of CdSe quantum dots are studied by first principle and semi-empirical pseudopotentials calculations. They find that the amplitude of the quantum dot deformation potential is only slightly larger than the bulk value, and this increase is mostly caused by the off {Lambda} point deformation potentials in the bulk, which are larger in amplitude than the {Lambda} point deformation potential.

  8. Los Alamos Quantum Dots for Solar, Display Technology

    SciTech Connect (OSTI)

    Klimov, Victor

    2015-04-13

    Quantum dots are ultra-small bits of semiconductor matter that can be synthesized with nearly atomic precision via modern methods of colloidal chemistry. Their emission color can be tuned by simply varying their dimensions. Color tunability is combined with high emission efficiencies approaching 100 percent. These properties have recently become the basis of a new technology – quantum dot displays – employed, for example, in the newest generation of e-readers and video monitors.

  9. Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous

    Office of Scientific and Technical Information (OSTI)

    optical imaging, photothermal effect and thermometry (Journal Article) | SciTech Connect Journal Article: Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous optical imaging, photothermal effect and thermometry Citation Details In-Document Search Title: Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous optical imaging, photothermal effect and thermometry × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This

  10. Controlling thermal conductance through quantum dot roughening at

    Office of Scientific and Technical Information (OSTI)

    interfaces. (Journal Article) | SciTech Connect Journal Article: Controlling thermal conductance through quantum dot roughening at interfaces. Citation Details In-Document Search Title: Controlling thermal conductance through quantum dot roughening at interfaces. Abstract not provided. Authors: Hopkins, Patrick Edward ; Duda, John C. ; Petz, Christopher W. ; Floro, Jerrold A. Publication Date: 2011-01-01 OSTI Identifier: 1110382 Report Number(s): SAND2011-0398J 473795 DOE Contract Number:

  11. NREL and Partners Demonstrate Quantum Dots that Assemble Themselves - News

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

    Releases | NREL and Partners Demonstrate Quantum Dots that Assemble Themselves Surprising breakthrough could bolster quantum photonics, solar cell efficiency February 8, 2013 Scientists from the U.S. Department of Energy's National Renewable Energy Laboratory and other labs have demonstrated a process whereby quantum dots can self-assemble at optimal locations in nanowires, a breakthrough that could improve solar cells, quantum computing, and lighting devices. A paper on the new technology,

  12. Metal Halide Surface Treatment of Quantum Dots - Energy Innovation Portal

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

    Advanced Materials Advanced Materials Find More Like This Return to Search Metal Halide Surface Treatment of Quantum Dots National Renewable Energy Laboratory Contact NREL About This Technology Technology Marketing Summary Quantum dot (QD) solids are a solution-processed, composite thin film semiconductor system that is being developed for optoelectronics (display technology, solid state lighting, next generation photovoltaics, photodetector application, etc.). For photovoltaics, in addition to

  13. Improving PbS Quantum Dot Solar Cell Power Conversion Efficiency to an NREL-Certified 4.4% (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-01-01

    Transition metal oxide improves overall efficiency and maintains performance with inexpensive metals. A research team at the National Renewable Energy Laboratory (NREL) has demonstrated that inserting a transition metal oxide (TMO) between the lead sulfide (PbS) quantum dot (QD) layer and the metal electrode eliminates the Schottky barrier that impedes efficient hole extraction and thereby improves the overall conversion efficiency. This allows for inexpensive metals such as Al to be employed without loss of performance. n-type TMOs consisting of molybdenum oxide (MoO{sub x}) and vanadium oxide (V{sub 2}O{sub x}) were used as an efficient hole extraction layer (HEL) in heterojunction ZnO/PbS QD solar cells. A 4.4% NREL-certified device was reported based on the MoO{sub x} HEL with Al as the back contact material, representing a more than 65% efficiency improvement compared with the case of Au contacting the PbS QD layer directly. The team finds the acting mechanism of the HEL to be a dipole formed at the MoO{sub x} and PbS interface, which enhances band bending to allow efficient hole extraction from the valence band of the PbS layer by MoO{sub x}. The carrier transport to the metal anode is likely enhanced through shallow gap states in the MoO{sub x} layer.

  14. New Pathway Developed to Silicon Quantum Dot Devices (Fact Sheet), Highlights in Science, NREL (National Renewable Energy Laboratory)

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

    Researchers create a way to prepare doped nanocrystal solutions for solar thin films that are nontoxic and less expensive than heavy metal-based thin films. Scientists at the National Renewable Energy Laboratory (NREL) and the University of Minnesota have developed a method for preparing doped colloids (solutions) of silicon nanocrystals (NCs) as potential nontoxic infrared-absorbing and -emitting alternatives to metal chalcogenide quantum dots. Significant progress in the methods for preparing

  15. computational-hydraulics-for-transportation

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

    Transportation Workshop Sept. 23-24, 2009 Argonne TRACC Dr. Steven Lottes This email address is being protected from spambots. You need JavaScript enabled to view it. Announcement pdficon small The Transportation Research and Analysis Computing Center at Argonne National Laboratory will hold a workshop on the use of computational hydraulics for transportation applications. The goals of the workshop are: Bring together people who are using or would benefit from the use of high performance cluster

  16. transportation-system-modeling-webinar

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

    Webinar Announcement Webinar for the Intelligent Transportation Society of the Midwest (ITS Midwest) May 16, 2011 1:00 PM(CST) Hubert Ley Director, TRACC Argonne National Laboratory Argonne, Illinois High Performance Computing in Transportation Research - High Fidelity Transportation Models and More The Role of High-Performance Computing Because ITS relies on a very diverse collection of technologies, including communication and control technologies, advanced computing, information management

  17. Sustainable Transportation | Department of Energy

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

    Sustainable Transportation Sustainable Transportation Bioenergy Bioenergy Read more Hydrogen and Fuel Cells Hydrogen and Fuel Cells Read more Vehicles Vehicles Read more The Office of Energy Efficiency and Renewable Energy (EERE) leads U.S. researchers and other partners in making transportation cleaner and more efficient through solutions that put electric drive vehicles on the road and replace oil with clean domestic fuels. Through our Vehicle, Bioenergy, and Fuel Cell Technologies Offices,

  18. Effect of carrier dynamics and temperature on two-state lasing in semiconductor quantum dot lasers

    SciTech Connect (OSTI)

    Korenev, V. V. Savelyev, A. V.; Zhukov, A. E.; Omelchenko, A. V.; Maximov, M. V.

    2013-10-15

    It is analytically shown that the both the charge carrier dynamics in quantum dots and their capture into the quantum dots from the matrix material have a significant effect on two-state lasing phenomenon in quantum dot lasers. In particular, the consideration of desynchronization in electron and hole capture into quantum dots allows one to describe the quenching of ground-state lasing observed at high injection currents both qualitatevely and quantitatively. At the same time, an analysis of the charge carrier dynamics in a single quantum dot allowed us to describe the temperature dependences of the emission power via the ground- and excited-state optical transitions of quantum dots.

  19. Full counting statistics as a probe of quantum coherence in a side-coupled double quantum dot system

    SciTech Connect (OSTI)

    Xue, Hai-Bin

    2013-12-15

    We study theoretically the full counting statistics of electron transport through side-coupled double quantum dot (QD) based on an efficient particle-number-resolved master equation. It is demonstrated that the high-order cumulants of transport current are more sensitive to the quantum coherence than the average current, which can be used to probe the quantum coherence of the considered double QD system. Especially, quantum coherence plays a crucial role in determining whether the super-Poissonian noise occurs in the weak inter-dot hopping coupling regime depending on the corresponding QD-lead coupling, and the corresponding values of super-Poissonian noise can be relatively enhanced when considering the spins of conduction electrons. Moreover, this super-Poissonian noise bias range depends on the singly-occupied eigenstates of the system, which thus suggests a tunable super-Poissonian noise device. The occurrence-mechanism of super-Poissonian noise can be understood in terms of the interplay of quantum coherence and effective competition between fast-and-slow transport channels. -- Highlights: The FCS can be used to probe the quantum coherence of side-coupled double QD system. Probing quantum coherence using FCS may permit experimental tests in the near future. The current noise characteristics depend on the quantum coherence of this QD system. The super-Poissonian noise can be enhanced when considering conduction electron spin. The side-coupled double QD system suggests a tunable super-Poissonian noise device.

  20. Single InAs quantum dot coupled to different 'environments' in one wafer for quantum photonics

    SciTech Connect (OSTI)

    Yu, Ying; Shang, Xiang-Jun; Li, Mi-Feng; Zha, Guo-Wei; Xu, Jian-Xing; Wang, Li-Juan; Wang, Guo-Wei; Ni, Hai-Qiao; Dou, Xiuming; Sun, Baoquan; Niu, Zhi-Chuan

    2013-05-20

    Self assembled small InAs quantum dots (SQDs) were formed in various densities and environments using gradient InAs deposition on a non-rotating GaAs substrate. Two SQD environments (SQD I and SQD II) were characterized. SQD I featured SQDs surrounded by large QDs, and SQD II featured individual SQDs in the wetting layer (WL). Micro-photoluminescence of single QDs embedded in a cavity under various excitation powers and electric fields gave insight into carrier transport processes. Potential fluctuations of the WL in SQD II, induced by charge redistribution, show promise for charge-tunable QD devices; SQD I shows higher luminescence intensity as a single-photon source.

  1. Thick-shell nanocrystal quantum dots (Patent) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Patent: Thick-shell nanocrystal quantum dots Citation Details In-Document Search Title: Thick-shell nanocrystal quantum dots You are accessing a document from the Department of...

  2. R&D Magazine: Windows into Solar Power Sources with Quantum Dots

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

    R&D Magazine: Windows into Solar Power Sources with Quantum Dots August 30, 2015 R&D Magazine: Windows into Solar Power Sources with Quantum Dots A luminescent solar concentrator...

  3. Density-Dependent Carrier Dynamics in a Quantum Dots-in-a-Well...

    Office of Scientific and Technical Information (OSTI)

    Dynamics in a Quantum Dots-in-a-Well Heterostructure. Citation Details In-Document Search Title: Density-Dependent Carrier Dynamics in a Quantum Dots-in-a-Well Heterostructure. ...

  4. Research Highlight

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

    Pollution Hitches Ride to Arctic Download a printable PDF Submitter: Zelenyuk-Imre, A., Pacific Northwest National Laboratory Area of Research: Aerosol Properties Working Group(s): Aerosol Life Cycle Journal Reference: Zelenyuk A, D Imre, J Beranek, E Abramson, J Wilson, and M Shrivastava. 2012. "Synergy between secondary organic aerosols and long-range transport of polycyclic aromatic hydrocarbons." Environmental Science & Technology, 46(22), doi:10.1021/es302743z. When airborne

  5. Surface Induced Magnetism in Quantum Dots

    SciTech Connect (OSTI)

    Meulenberg, R W; Lee, J I

    2009-08-20

    The study of nanometer sized semiconductor crystallites, also known as quantum dots (QDs), has seen rapid advancements in recent years in scientific disciplines ranging from chemistry, physics, biology, materials science, and engineering. QD materials of CdSe, ZnSe, InP, as well as many others, can be prepared in the size range of 1-10 nm producing uniform, nearly monodisperse materials that are typically coated with organic molecules [1-3]. The strength of charge carrier confinement, which dictates the size-dependent properties, in these QDs depends on the nature of the material and can be correlated to the Bohr radius for the system of interest. For instance, the Bohr radius for CdSe is {approx} 5 nm, while in the more covalent structure of InP, the Bohr radius approaches {approx} 10 nm. The study of CdSe QDs has been particularly extensive during the last decade because they exhibit unique and tunable optical properties and are readily synthesized with high-crystallinity and narrow size dispersions. Although the core electronic properties of CdSe are explained in terms of the quantum confinement model, experimental efforts to elucidate the surface structure of these materials have been limited. Typically, colloidal CdSe QDs are coated with an organic surfactant, which typically consists of an organo-phosphine, -thiol, or -amine, that has the function of energetically relaxing defect states via coordination to partially coordinated surface atoms. The organic surfactant also acts to enhance carrier confinement and prevent agglomeration of the particles. Chemically, it has been shown that the bonding of the surfactant to the CdSe QD occurs through Cd atoms resulting cleavage of the Se atoms and formation of a Cd-rich (i.e. non-stoichiometric) particle [5].

  6. Research and development of Proton-Exchange-Membrane (PEM) fuel cell system for transportation applications. Fuel cell infrastructure and commercialization study

    SciTech Connect (OSTI)

    1996-11-01

    This paper has been prepared in partial fulfillment of a subcontract from the Allison Division of General Motors under the terms of Allison`s contract with the U.S. Department of Energy (DE-AC02-90CH10435). The objective of this task (The Fuel Cell Infrastructure and Commercialization Study) is to describe and prepare preliminary evaluations of the processes which will be required to develop fuel cell engines for commercial and private vehicles. This report summarizes the work undertaken on this study. It addresses the availability of the infrastructure (services, energy supplies) and the benefits of creating public/private alliances to accelerate their commercialization. The Allison prime contract includes other tasks related to the research and development of advanced solid polymer fuel cell engines and preparation of a demonstration automotive vehicle. The commercialization process starts when there is sufficient understanding of a fuel cell engine`s technology and markets to initiate preparation of a business plan. The business plan will identify each major step in the design of fuel cell (or electrochemical) engines, evaluation of the markets, acquisition of manufacturing facilities, and the technical and financial resources which will be required. The process will end when one or more companies have successfully developed and produced fuel cell engines at a profit. This study addressed the status of the information which will be required to prepare business plans, develop the economic and market acceptance data, and to identify the mobility, energy and environment benefits of electrochemical or fuel cell engines. It provides the reader with information on the status of fuel cell or electrochemical engine development and their relative advantages over competitive propulsion systems. Recommendations and descriptions of additional technical and business evaluations that are to be developed in more detail in Phase II, are included.

  7. Energy levels of double triangular graphene quantum dots

    SciTech Connect (OSTI)

    Liang, F. X.; Jiang, Z. T. Zhang, H. Y.; Li, S.; Lv, Z. T.

    2014-09-28

    We investigate theoretically the energy levels of the coupled double triangular graphene quantum dots (GQDs) based on the tight-binding Hamiltonian model. The double GQDs including the ZZ-type, ZA-type, and AA-type GQDs with the two GQDs having the zigzag or armchair boundaries can be coupled together via different interdot connections, such as the direct coupling, the chains of benzene rings, and those of carbon atoms. It is shown that the energy spectrum of the coupled double GQDs is the amalgamation of those spectra of the corresponding two isolated GQDs with the modification triggered by the interdot connections. The interdot connection is inclined to lift up the degeneracies of the energy levels in different degree, and as the connection changes from the direct coupling to the long chains, the removal of energy degeneracies is suppressed in ZZ-type and AA-type double GQDs, which indicates that the two coupled GQDs are inclined to become decoupled. Then we consider the influences on the spectra of the coupled double GQDs induced by the electric fields applied on the GQDs or the connection, which manifests as the global spectrum redistribution or the local energy level shift. Finally, we study the symmetrical and asymmetrical energy spectra of the double GQDs caused by the substrates supporting the two GQDs, clearly demonstrating how the substrates affect the double GQDs' spectrum. This research elucidates the energy spectra of the coupled double GQDs, as well as the mechanics of manipulating them by the electric field and the substrates, which would be a significant reference for designing GQD-based devices.

  8. Quasi-periodic quantum dot arrays produced by electrochemical synthesis

    SciTech Connect (OSTI)

    Bandyopadhyay, S.; Miller, A.E.; Yue, D.F.; Banerjee, G.; Ricker, R.E.; Jones, S.; Eastman, J.A.; Baugher, E.; Chandrasekhar, M.

    1994-06-01

    We discuss a ``gentle`` electrochemical technique for fabricating quasi-periodic quantum dot arrays. The technique exploits a self-organizing phenomenon to produce quasi-periodic arrangement of dots and provides excellent control over dot size and interdot spacing. Unlike conventional nanolithography, it does not cause radiation damage to the structures during exposure to pattern delineating beams (e-beam, ion-beam or x-ray). Moreover, it does not require harsh processing steps like reactive ion etching, offers a minimum feature size of {approximately}40 {angstrom}, allows the fabrication of structures on nonplanar surfaces (e.g. spherical or cylindrical substrates), is amenable to mass production (millions of wafers can be processed simultaneously) and is potentially orders of magnitude cheaper than conventional nanofabrication. In this paper, we describe our initial results and show the promise of this technique for low-cost and high-yield nanosynthesis.

  9. Transportation Energy Futures Analysis Snapshot

    Broader source: Energy.gov [DOE]

    Transportation currently accounts for 71% of total U.S. petroleum use and 33% of the nation's total carbon emissions. The TEF project explores how combining multiple strategies could reduce GHG emissions and petroleum use by 80%. Researchers examined four key areas – lightduty vehicles, non-light-duty vehicles, fuels, and transportation demand – in the context of the marketplace, consumer behavior, industry capabilities, technology and the energy and transportation infrastructure. The TEF reports support DOE long-term planning. The reports provide analysis to inform decisions about transportation energy research investments, as well as the role of advanced transportation energy technologies and systems in the development of new physical, strategic, and policy alternatives.

  10. International Conference on Surface Transportation System Resilience...

    Broader source: Energy.gov (indexed) [DOE]

    practices and state of the art research results on how to adapt surface transportation networks to the potential impacts of climate change and extreme weather events. Learn More......

  11. Internal Labeling Technique Tracks Nanoparticle Transport - Energy...

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

    Technology Marketing SummaryTo track the transport of nanoscale particles and core-shell particles in biological and environmental systems, ORNL researchers developed a way to...

  12. Transportation technology R&D?Steve Ciatti

    ScienceCinema (OSTI)

    Steve Ciatti

    2013-06-05

    Argonne researcher Steve Ciatti talks about the emerging technologies in transportation, as well as the current technology being developed at the lab and placed on the market.

  13. FEMP and Department of Transportation Partnership Wins GreenGov Award |

    Office of Environmental Management (EM)

    Department of Energy and Department of Transportation Partnership Wins GreenGov Award FEMP and Department of Transportation Partnership Wins GreenGov Award November 6, 2014 - 4:46pm Addthis The FEMP half of the award-winning GreenGov Presidential Green Dream Team. Pictured left to right: Brad Gustafson, Mark Reichhardt, David Boomsma, Sarah Jensen, and FEMP Director Tim Unruh. DOT team members (not pictured) include Nancy Henry, Hetal Jain, Brent Kurapatskie, Steve Renzi, and Eugene Tumblin.

  14. Task 3: PNNL Visit by JAEA Researchers to Participate in TODAM Code Applications to Fukushima Rivers and to Evaluate the Feasibility of Adaptation of FLESCOT Code to Simulate Radionuclide Transport in the Pacific Ocean Coastal Water Around Fukushima

    SciTech Connect (OSTI)

    Onishi, Yasuo

    2013-03-29

    Four JAEA researchers visited PNNL for two weeks in February, 2013 to learn the PNNL-developed, unsteady, one-dimensional, river model, TODAM and the PNNL-developed, time-dependent, three dimensional, coastal water model, FLESCOT. These codes predict sediment and contaminant concentrations by accounting sediment-radionuclide interactions, e.g., adsorption/desorption and transport-deposition-resuspension of sediment-sorbed radionuclides. The objective of the river and coastal water modeling is to simulate • 134Cs and 137Cs migration in Fukushima rivers and the coastal water, and • their accumulation in the river and ocean bed along the Fukushima coast. Forecasting the future cesium behavior in the river and coastal water under various scenarios would enable JAEA to assess the effectiveness of various on-land remediation activities and if required, possible river and coastal water clean-up operations to reduce the contamination of the river and coastal water, agricultural products, fish and other aquatic biota. PNNL presented the following during the JAEA visit to PNNL: • TODAM and FLESCOT’s theories and mathematical formulations • TODAM and FLESCOT model structures • Past TODAM and FLESCOT applications • Demonstrating these two codes' capabilities by applying them to simple hypothetical river and coastal water cases. • Initial application of TODAM to the Ukedo River in Fukushima and JAEA researchers' participation in its modeling. PNNL also presented the relevant topics relevant to Fukushima environmental assessment and remediation, including • PNNL molecular modeling and EMSL computer facilities • Cesium adsorption/desorption characteristics • Experiences of connecting molecular science research results to macro model applications to the environment • EMSL tour • Hanford Site road tour. PNNL and JAEA also developed future course of actions for joint research projects on the Fukushima environmental and remediation assessments.

  15. Self-organized formation of quantum dots of a material on a substrate

    DOE Patents [OSTI]

    Zhang, Zhenyu (232 Long Bow Rd., Knoxville, TN 37922); Wendelken, John F. (925 Suwanee Rd., Knoxville, TN 37923); Chang, Ming-Che (F4-2, No. 178 Sec 5 Minsheng East Rd., Taipei, TW); Pai, Woei Wu (1F, No. 17, Alley 11, Lane 202, Ming Chyuan Rd., Pan Chou City, Taipei County, TW)

    2001-01-01

    Systems and methods are described for fabricating arrays of quantum dots. A method for making a quantum dot device, includes: forming clusters of atoms on a substrate; and charging the clusters of atoms such that the clusters of atoms repel one another. The systems and methods provide advantages because the quantum dots can be ordered with regard to spacing and/or size.

  16. Analysis of the efficiency of intermediate band solar cells based on quantum dot supercrystals

    SciTech Connect (OSTI)

    Heshmati, S; Golmohammadi, S; Abedi, K; Taleb, H

    2014-03-28

    We have studied the influence of the quantum-dot (QD) width and the quantum-dot conduction band (QD-CB) offset on the efficiency of quantum-dot intermediate band solar cells (QD-IBSCs). Simulation results demonstrate that with increasing QD-CB offset and decreasing QD width, the maximum efficiency is achieved. (laser applications and other topics in quantum electronics)

  17. Quantum-dot based nanothermometry in optical plasmonic recording media

    SciTech Connect (OSTI)

    Maestro, Laura Martinez; Zhang, Qiming; Li, Xiangping; Gu, Min; Jaque, Daniel

    2014-11-03

    We report on the direct experimental determination of the temperature increment caused by laser irradiation in a optical recording media constituted by a polymeric film in which gold nanorods have been incorporated. The incorporation of CdSe quantum dots in the recording media allowed for single beam thermal reading of the on-focus temperature from a simple analysis of the two-photon excited fluorescence of quantum dots. Experimental results have been compared with numerical simulations revealing an excellent agreement and opening a promising avenue for further understanding and optimization of optical writing processes and media.

  18. Optical control of the emission direction of a quantum dot

    SciTech Connect (OSTI)

    Luxmoore, I. J.; Wasley, N. A.; Fox, A. M.; Skolnick, M. S.; Ramsay, A. J.; Thijssen, A. C. T.; Oulton, R.; Hugues, M.; CNRS-CRHEA, rue Bernard Grgory, 06560 Valbonne

    2013-12-09

    Using the helicity of a non-resonant excitation laser, control over the emission direction of an InAs/GaAs quantum dot is demonstrated. The quantum dot is located off-center in a crossed-waveguide structure, such that photons of opposite circular polarization are emitted into opposite waveguide directions. By preferentially exciting spin-polarized excitons, the direction of emission can therefore be controlled. The directional control is quantified by using the ratio of the intensity of the light coupled into the two waveguides, which reaches a maximum of 35%.

  19. Overview and Progress of the Exploratory Technology Research...

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

    Exploratory Technology Research Activity: Batteries for Advanced Transportation Technologies (BATT) Overview and Progress of the Exploratory Technology Research Activity: Batteries...

  20. Increased InAs quantum dot size and density using bismuth as a surfactant

    SciTech Connect (OSTI)

    Dasika, Vaishno D.; Krivoy, E. M.; Nair, H. P.; Maddox, S. J.; Park, K. W.; Yu, E. T.; Bank, S. R.; Jung, D.; Lee, M. L.

    2014-12-22

    We have investigated the growth of self-assembled InAs quantum dots using bismuth as a surfactant to control the dot size and density. We find that the bismuth surfactant increases the quantum dot density, size, and uniformity, enabling the extension of the emission wavelength with increasing InAs deposition without a concomitant reduction in dot density. We show that these effects are due to bismuth acting as a reactive surfactant to kinetically suppress the surface adatom mobility. This mechanism for controlling quantum dot density and size has the potential to extend the operating wavelength and enhance the performance of various optoelectronic devices.

  1. Structure of droplet-epitaxy-grown InAs/GaAs quantum dots

    SciTech Connect (OSTI)

    Cohen, Eyal; Yochelis, Shira; Westreich, Ohad; Shusterman, Sergey; Kumah, Divine P.; Clarke, Roy; Yacoby, Yizhak; Paltiel, Yossi

    2011-09-06

    We have used a direct x-ray phasing method, coherent Bragg rod analysis, to obtain sub-angstrom resolution electron density maps of the InAs/GaAs dot system. The dots were grown by the droplet heteroepitaxy (DHE) technique and their structural and compositional properties are compared with those of dots grown by the strain-driven Stranski-Krastanov method. Our results show that the Ga diffusion into the DHE-grown dots is somewhat larger; however, other characteristics such as the composition of the dots uppermost layers, the interlayer spacing, and the bowing of the atomic layers are similar.

  2. LANL, LLNL researchers among Early Career Research Program award...

    National Nuclear Security Administration (NNSA)

    Program awards for 2013. LLNL physicist Yuan Ping's project, selected by the Office of Fusion Research, aims to provide high quality data on critical energy transport properties of...

  3. Magnetic field induced quantum dot brightening in liquid crystal synergized magnetic and semiconducting nanoparticle composite assemblies

    SciTech Connect (OSTI)

    Amaral, Jose Jussi; Wan, Jacky; Rodarte, Andrea L.; Ferri, Christopher; Quint, Makiko T.; Pandolfi, Ronald J.; Scheibner, Michael; Hirst, Linda S.; Ghosh, Sayantani

    2014-10-22

    The design and development of multifunctional composite materials from artificial nano-constituents is one of the most compelling current research areas. This drive to improve over nature and produce meta-materials has met with some success, but results have proven limited with regards to both the demonstration of synergistic functionalities and in the ability to manipulate the material properties post-fabrication and in situ. Here, magnetic nanoparticles (MNPs) and semiconducting quantum dots (QDs) are co-assembled in a nematic liquid crystalline (LC) matrix, forming composite structures in which the emission intensity of the quantum dots is systematically and reversibly controlled with a small applied magnetic field (<100 mT). This magnetic field-driven brightening, ranging between a two- to three-fold peak intensity increase, is a truly cooperative effect: the LC phase transition creates the co-assemblies, the clustering of the MNPs produces LC re-orientation at atypical low external field, and this re-arrangement produces compaction of the clusters, resulting in the detection of increased QD emission. These results demonstrate a synergistic, reversible, and an all-optical process to detect magnetic fields and additionally, as the clusters are self-assembled in a fluid medium, they offer the possibility for these sensors to be used in broad ranging fluid-based applications.

  4. Revolutionary Method for Increasing the Efficiency of White Light Quantum Dot LEDs

    SciTech Connect (OSTI)

    Duty, Chad E [ORNL; Bennett, Charlee J C [ORNL; Sabau, Adrian S [ORNL; Jellison Jr, Gerald Earle [ORNL; Boudreaux, Philip R [ORNL; Walker, Steven C [ORNL; Ott, Ronald D [ORNL

    2011-01-01

    Covering a light-emitting diode (LED) with quantum dots (QDs) can produce a broad spectrum of white light. However, current techniques for applying QDs to LEDs suffer from a high density of defects and a non-uniform distribution of QDs, which respec-tively diminish the efficiency and quality of emitted light. Oak Ridge National Laboratory (ORNL) has the unique capability to thermally anneal QD structures at extremely high power densities for very short durations. This process, called pulse thermal proc-essing (PTP), reduces the number of point defects while main-taining the size and shape of the original QD nanostructure. Therefore, the efficiency of the QD wavelength conversion layer is improved without altering the emission spectrum defined by the size distribution of the quantum dot nanoparticles. The cur-rent research uses a thermal model to predict annealing tempera-tures during PTP and demonstrates up to a 300% increase in pho-toluminescence for QDs on passive substrates

  5. Nanocrystal quantum dots: building blocks for tunable optical amplifiers and lasers

    SciTech Connect (OSTI)

    Mikhailovsky, A. A.; Malko, A. V.; Klimov, V. I.; Leatherdale, C. A.; Eisler, H-J.; Bawendi, M.; Hollingsworth, J. A.

    2001-01-01

    We study optical processes relevant to optical amplification and lasing in CdSe nanocrystal quantum dots (NQD). NQDs are freestanding nanoparticles prepared using solution-based organometallic reactions originally developed for the Cd chalcogenides, CdS, CdSe and CdTe [J. Am. Chem. Soc. 115, 8706 (1993)]. We investigate NQDs with diameters ranging from 2 to 8 nm. Due to strong quantum confinement, they exhibit size-dependent spectral tunability over an energy range as wide as several hundred meV. We observe a strong effect of the matrix/solvent on optical gain properties of CdSe NQDs. In most of the commonly used solvents (such as hexane and toluene), gain is suppressed due to strong photoinduced absorption associated with carriers trapped at solvent-related interface states. In contrast, matrix-free close packed NQD films (NQD solids) exhibit large optical gain with a magnitude that is sufficiently high for the optical gain to successfully compete with multiparticle Auger recombination [Science 287, 10117 (2000)]. These films exhibit narrowband stimulated emission at both cryogenic and room temperature, and the emission color is tunable with dot size [Science 290, 314 (2000)]. Moreover, the NQD films can be incorporated into microcavities of different geometries (micro-spheres, wires, tubes) that produce lasing in whispering gallery modes. The facile preparation, chemical flexibility and wide-range spectral tunability due to strong quantum confinement are the key advantages that should motivate research into NQD applications in optical amplifiers and lasers.

  6. Magnetic field induced quantum dot brightening in liquid crystal synergized magnetic and semiconducting nanoparticle composite assemblies

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

    Amaral, Jose Jussi; Wan, Jacky; Rodarte, Andrea L.; Ferri, Christopher; Quint, Makiko T.; Pandolfi, Ronald J.; Scheibner, Michael; Hirst, Linda S.; Ghosh, Sayantani

    2014-10-22

    The design and development of multifunctional composite materials from artificial nano-constituents is one of the most compelling current research areas. This drive to improve over nature and produce ‘meta-materials’ has met with some success, but results have proven limited with regards to both the demonstration of synergistic functionalities and in the ability to manipulate the material properties post-fabrication and in situ. Here, magnetic nanoparticles (MNPs) and semiconducting quantum dots (QDs) are co-assembled in a nematic liquid crystalline (LC) matrix, forming composite structures in which the emission intensity of the quantum dots is systematically and reversibly controlled with a small appliedmore » magnetic field (<100 mT). This magnetic field-driven brightening, ranging between a two- to three-fold peak intensity increase, is a truly cooperative effect: the LC phase transition creates the co-assemblies, the clustering of the MNPs produces LC re-orientation at atypical low external field, and this re-arrangement produces compaction of the clusters, resulting in the detection of increased QD emission. These results demonstrate a synergistic, reversible, and an all-optical process to detect magnetic fields and additionally, as the clusters are self-assembled in a fluid medium, they offer the possibility for these sensors to be used in broad ranging fluid-based applications.« less

  7. An evaluation of Department of Transportation specification packages

    SciTech Connect (OSTI)

    Ratledge, J.E.; Rawl, R.R.

    1992-01-01

    Specification packages are broad families of package designs developed and authorized by the US Department of Transportation (DOT) and the Nuclear Regulatory Commission (NRC) for transport of certain Type B and fissile radioactive materials, with each specification containing a number of designs of various sizes. The specification package designs have remained essentially unchanged in a changing regulatory environment. Changes to package designs or authorized contents under the DOT system can be accomplished by rule making action, but there has been little updating of the designs over the years. Many of the individual package designs are no longer supported by reasonably current safety analyses. Since the publication of these specifications, there have been changes in regulatory requirements and improvements in methods of testing and analysis. Additionally, contemplated revisions to the DOT and NRC regulations to bring design requirements into accord with IAEA Safety Series No. 6, 1985 Edition would eliminate fissile classes and require resistance to a crush test for small Type B packages meeting certain criteria. The NRC has requested that the Oak Ridge National Laboratory (ORNL) staff review the safety documentation of the specification packages to determine the possible need for further testing and analysis, modifications to the designs, and, perhaps, elimination of any designs for which there is insufficient demonstration of compliance with current and proposed requirements. This paper will present a summary of the technical data and information concerning the use of the packages that has been received to date.

  8. An evaluation of Department of Transportation specification packages

    SciTech Connect (OSTI)

    Ratledge, J.E.; Rawl, R.R.

    1992-11-01

    Specification packages are broad families of package designs developed and authorized by the US Department of Transportation (DOT) and the Nuclear Regulatory Commission (NRC) for transport of certain Type B and fissile radioactive materials, with each specification containing a number of designs of various sizes. The specification package designs have remained essentially unchanged in a changing regulatory environment. Changes to package designs or authorized contents under the DOT system can be accomplished by rule making action, but there has been little updating of the designs over the years. Many of the individual package designs are no longer supported by reasonably current safety analyses. Since the publication of these specifications, there have been changes in regulatory requirements and improvements in methods of testing and analysis. Additionally, contemplated revisions to the DOT and NRC regulations to bring design requirements into accord with IAEA Safety Series No. 6, 1985 Edition would eliminate fissile classes and require resistance to a crush test for small Type B packages meeting certain criteria. The NRC has requested that the Oak Ridge National Laboratory (ORNL) staff review the safety documentation of the specification packages to determine the possible need for further testing and analysis, modifications to the designs, and, perhaps, elimination of any designs for which there is insufficient demonstration of compliance with current and proposed requirements. This paper will present a summary of the technical data and information concerning the use of the packages that has been received to date.

  9. Intermediate-band photosensitive device with quantum dots having tunneling barrier embedded in organic matrix

    DOE Patents [OSTI]

    Forrest, Stephen R. (Ann Arbor, MI)

    2008-08-19

    A plurality of quantum dots each have a shell. The quantum dots are embedded in an organic matrix. At least the quantum dots and the organic matrix are photoconductive semiconductors. The shell of each quantum dot is arranged as a tunneling barrier to require a charge carrier (an electron or a hole) at a base of the tunneling barrier in the organic matrix to perform quantum mechanical tunneling to reach the respective quantum dot. A first quantum state in each quantum dot is between a lowest unoccupied molecular orbital (LUMO) and a highest occupied molecular orbital (HOMO) of the organic matrix. Wave functions of the first quantum state of the plurality of quantum dots may overlap to form an intermediate band.

  10. Sustainable Transportation Success Stories | Department of Energy

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

    Sustainable Transportation Success Stories Sustainable Transportation Success Stories Sustainable Transportation Success Stories The Office of Energy Efficiency and Renewable Energy's (EERE) successes in converting tax dollars into sustainable transportation solutions are important steps in the drive toward cleaner vehicles for all purposes. Learn how EERE's investments in bioenergy, hydrogen and fuel cell research, and vehicle technologies are putting electric drive vehicles on the road and

  11. NREL: Transportation Research - Fleet Test and Evaluation

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

    Fleet Test and Evaluation Photo of medium-duty truck with the words plug-in all electric vehicle on its side. NREL evaluates the real-world performance of advanced medium- and heavy-duty fleet vehicles-such as this all-electric truck-compared to conventional vehicles. Photo courtesy of Smith Electric Vehicles Photo of heavy-duty truck in a laboratory setting with tubes and chains connecting the vehicle to scientific equipment. As part of its vehicle performance evaluations, NREL uses the

  12. NREL: Transportation Research - Systems Analysis and Integration

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

    wireless power transfer for on-road electric vehicles, as depicted in the e-roadway animation. NREL's systems analysis and integration work supports a wide range of...

  13. NREL: Transportation Research - Electric Vehicle Grid Integration

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

    of building energy systems, utility grids, renewable energy sources, and ... to enable PEV communication with the smart grid and to create opportunities for ...

  14. NREL: Transportation Research - Sustainable Mobility Initiative

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

    a focus on bi-directional charging, wireless electric vehicle (EV) charging, vehicle-to-grid power flow and controls, and second use of EV batteries for utility energy storage....

  15. NREL: Transportation Research - Power Electronics and Electric...

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

    subsystem at the appropriate time. Examples of power electronics components include inverters, converters, and chargers. Power electronics also determine the exact nature and...

  16. NREL: Transportation Research - Fuel Combustion Laboratory

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

    Combustion Laboratory NREL's Fuel Combustion Laboratory focuses on characterizing fuels at the molecular level. This information can then be used to understand and predict a fuel's effect on engine performance and emissions. By understanding the effects of fuel chemistry on ignition, as well as the potential emissions impacts, we can develop fuels that enable more efficient engine designs, using both today's technology and future advanced combustion concepts. This lab supports the Renewable

  17. NREL: Transportation Research - News Release Archives

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

    1 December 13, 2011 NREL Adds Electric Vehicle to its Advanced Vehicle Fleet NREL will use the new electric vehicle for studies related to charge management and performance, bi-directional charging, and electric vehicle grid integration. December 12, 2011 Energy Department Awards More Than $7 Million for Innovative Hydrogen Storage Technologies in Fuel Cell Electric Vehicles These projects will help lower the costs and increase the performance of hydrogen storage systems by developing innovative

  18. NREL: Transportation Research - Systems Analysis and Integration

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

    Publications Systems Analysis and Integration Publications NREL publishes technical reports, fact sheets, and other documents about its systems analysis and integration activities. For a complete collection of publications, search NREL's Publications Database or find publications via the following author and keyword selections: Authors: Robb Barnitt Brennan Borlaug Aaron Brooker Evan Burton Yuche Chen Josh Eichman Jeff Gonder Jacob Holden Tony Markel Marc Melaina Michael Penev Laurie Ramroth

  19. NREL: Transportation Research - Truck Platooning Testing

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

    Truck Platooning Testing Photo of two tractor trailer trucks driving in close proximity. NREL conducted track testing of platooned tractors with 53-ft trailers at the 8.5-mile Uvalde track in San Antonio, Texas. Photo courtesy of Peloton NREL's fleet test and evaluation team assesses the fuel savings potential of semiautomated truck platooning of line-haul sleeper cabs with modern aerodynamics. Platooning reduces aerodynamic drag by grouping vehicles together and safely decreasing the distance

  20. NREL: Transportation Research - Vehicle Thermal Management Publications

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

    Publications Explore NREL's recent publications about light- and heavy-duty vehicle thermal management. For the complete collection of NREL's vehicle thermal management publications, search the NREL Publications Database. All Light-Duty Electric-Drive Light-Duty Conventional Heavy-Duty 2015 Combined Fluid Loop Thermal Management for Electric Drive Vehicle Range Improvement. Leighton, D. (2015). SAE Int. J. Passeng. Cars - Mech. Syst. 8(2):711-720. (Presented at the SAE 2015 World Congress and

  1. NREL: Transportation Research - Compare Vehicle Technologies

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

    of vehicles on today's roads, while developing the electric, fuel cell, and biofuel technologies needed to transition to a virtually net-zero emissions, non-polluting fleet. ...

  2. NREL: Transportation Research - Data, Models, and Tools

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

    consumer demand for different vehicle types based on income distribution and other demographic attributes in a given region. ADOPT's market predictions have been extensively...

  3. TRANSFORUM News from Argonne's Transportation Research Program

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

    adoption of these vehicles, particularly in more difficult markets, and a rapidly growing charging infrastructure is taking hold. But like the Chinese concept of yin and yang, with...

  4. NREL: Transportation Research - Future Automotive Systems Technology...

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

    (drag, acceleration, ascent, and rolling resistance) Powertrain components (engine, motor, battery, and auxiliary loads) Regenerative braking Energy management strategies...

  5. New Transportation Technology | GE Global Research

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

    decade, the U.S. government has enacted a number of rules designed to reduce smog and air pollution in cities and... Read More A Recipe for Powering Next-Generation Electric...

  6. Development of an analysis capability for the National Transportation System

    SciTech Connect (OSTI)

    Anson, D.; Nelson, R.

    1997-10-24

    The purpose of this report is to examine the Department of Transportation`s (DOT) National Transportation System (NTS) initiative, to document what has been learned, and to outline a National Transportation Network Analysis Capability (NTNAC) based on a ``TRANSIMS-like`` approach. This study was conducted over a two month period at the end of FY1997. The scope of the effort was carefully defined to accommodate the short time horizon and to provide focus to a very large analytical problem. The objectives were to: (1) define the NTS and the NTS problem; (2) identify problem characteristics; (3) describe an analytical solution based on the TRANSIMS approach; (4) identify data requirements and availability; (5) develop criteria for a scenario to be used in a prototype demonstration; and (6) select a scenario for the prototype demonstration.

  7. Polymer matrix composites research: A survey of federally sponsored programs

    SciTech Connect (OSTI)

    Not Available

    1990-06-01

    This report identifies research conducted by agencies of the federal government other than the Department of Energy (DOE) in the area of advanced polymer matrix composites (PMCs). DOE commissioned the report to avoid duplicating other agencies' efforts in planning its own research program for PMCs. PMC materials consist of high-strength, short or continuous fibers fused together by an organic matrix. Compared to traditional structural metals, PMCs provide greater strength and stiffness, reduced weight and increased heat resistance. The key contributors to PMC research identified by the survey are the Department of Defense (DOD), the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and the Department of Transportation (DOT). The survey identified a total of 778 projects. More than half of the total projects identified emphasize materials research with a goal toward developing materials with improved performance. Although an almost equal number of identified materials projects focus on thermosets and thermoplastics receive more attention because of their increased impact resistance and their easy formability and re-formability. Slightly more than one third of projects identified target structures research. Only 15 percent of the projects identified focus on manufacturing techniques, despite the need for efficient, economical methods manufacturing products constructed of PMCs--techniques required for PMCs to gain widespread acceptance. Three issues to be addressed concerning PMCs research are economy of use, improvements in processing, and education and training. Five target technologies have been identified that could benefit greatly from increased use of PMCs: aircraft fuselages, automobile frames, high-speed machinery, electronic packaging, and construction.

  8. Research Techniques

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

    Research Techniques Research Techniques Print Coming Soon

  9. InGaAs/GaAs (110) quantum dot formation via step meandering

    SciTech Connect (OSTI)

    Diez-Merino, Laura; Tejedor, Paloma

    2011-07-01

    InGaAs (110) semiconductor quantum dots (QDs) offer very promising prospects as a material base for a new generation of high-speed spintronic devices, such as single electron transistors for quantum computing. However, the spontaneous formation of InGaAs QDs is prevented by two-dimensional (2D) layer-by-layer growth on singular GaAs (110) substrates. In this work we have studied, by using atomic force microscopy and photoluminescence spectroscopy (PL), the growth of InGaAs/GaAs QDs on GaAs (110) stepped substrates by molecular beam epitaxy (MBE), and the modification of the adatom incorporation kinetics to surface steps in the presence of chemisorbed atomic hydrogen. The as-grown QDs exhibit lateral dimensions below 100 nm and emission peaks in the 1.35-1.37 eV range. It has been found that a step meandering instability derived from the preferential attachment of In adatoms to [110]-step edges relative to [11n]-type steps plays a key role in the destabilization of 2D growth that leads to 3D mound formation on both conventional and H-terminated vicinal substrates. In the latter case, the driving force for 3D growth via step meandering is enhanced by H-induced upward mass transport in addition to the lower energy cost associated with island formation on H-terminated substrates, which results in a high density array of InGaAs/GaAs dots selectively nucleated on the terrace apices with reduced lateral dimensions and improved PL efficiency relative to those of conventional MBE-grown samples.

  10. Quantitative Imaging and In Situ Concentration Measurements of Quantum Dot Nanomaterials in Variably Saturated Porous Media

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

    Uyuşur, Burcu; Snee, Preston T.; Li, Chunyan; Darnault, Christophe J. G.

    2016-01-01

    Knowledge of the fate and transport of nanoparticles in the subsurface environment is limited, as techniques to monitor and visualize the transport and distribution of nanoparticles in porous media and measure their in situ concentrations are lacking. To address these issues, we have developed a light transmission and fluorescence method to visualize and measure in situ concentrations of quantum dot (QD) nanoparticles in variably saturated environments. Calibration cells filled with sand as porous medium and various known water saturation levels and QD concentrations were prepared. By measuring the intensity of the light transmitted through porous media exposed to fluorescent lightmore » and by measuring the hue of the light emitted by the QDs under UV light exposure, we obtained simultaneously in situ measurements of water saturation and QD nanoparticle concentrations with high spatial and temporal resolutions. Water saturation was directly proportional to the light intensity. A linear relationship was observed between hue-intensity ratio values and QD concentrations for constant water saturation levels. The advantages and limitations of the light transmission and fluorescence method as well as its implications for visualizing and measuring in situ concentrations of QDs nanoparticles in the subsurface environment are discussed.« less

  11. transportation-systems-modeling-training

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

    Training Table of Contents Date Location Integrated Transportation Models Workshop at ITM 2012 April 29, 2012 Hyatt Regency Tampa, FL TRANSIMS Training Course April 14-15, 2011 James E. Clyburn University Transportation Center Orangeburg, SC TRANSIMS RTSTEP Guest Lecturer March 29, 2011 Argonne TRACC Argonne, IL TRANSIMS Training Course January 19-21 2011 Argonne TRACC Argonne, IL TRANSIMS Training Course September 7-8, 2010 Turner Fairbank Highway Research Center Washington D.C. Network

  12. Research Highlight

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

    Clouds Re-gathered by Wind Shear Download a printable PDF Submitter: Yang, Q., Pacific Northwest National Laboratory Area of Research: Cloud-Aerosol-Precipitation Interactions Working Group(s): Cloud-Aerosol-Precipitation Interactions Journal Reference: Yang Q, RC Easter, P Campuzano-Jost, JL Jimenez, JD Fast, SJ Ghan, H Wang, LK Berg, MC Barth, Y Liu, MB Shrivastava, B Singh, H Morrison, J Fan, CL Ziegler, M Bela, E Apel, GS Diskin, T Mikoviny, and A Wisthaler. 2015. "Aerosol transport and

  13. Research Highlight

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

    Storm Clouds Take Rain on Rollercoaster Ride Download a printable PDF Submitter: Ovchinnikov, M., Pacific Northwest National Laboratory Area of Research: Cloud Processes Working Group(s): Cloud Life Cycle Journal Reference: Wong M, M Ovchinnikov, and M Wang. 2015. "Evaluation of subgrid-scale hydrometeor transport schemes using a high-resolution cloud-resolving model." Journal of the Atmospheric Sciences, 72(9), doi:10.1175/JAS-D-15-0060.1. Strong updrafts within the cloud propel their

  14. Research - Combustion Energy Frontier Research Center

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

    Research Research To facilitate better and more rapid coordination among the CEFRC members, Center research activities are organized into three Disciplinary Working Groups (DWGs) Chemistry: Theory (Coordinated by William H. Green) Chemistry: Experiment and Mechanisms (Coordinated by Hai Wang) Chemistry and Transport (Coordinated by Yiguang Ju) Additionally, the CEFRC has enlarged its scope of investigation by extending our prior focus on butanol to three unifying, thrust targets that define the

  15. Advanced method for increasing the efficiency of white light quantum dot LEDs

    SciTech Connect (OSTI)

    Duty, Chad E [ORNL; Bennett, Charlee J C [ORNL; Sabau, Adrian S [ORNL; Jellison Jr, Gerald Earle [ORNL; Boudreaux, Philip R [ORNL; Walker, Steven C [ORNL; Ott, Ronald D [ORNL

    2011-01-01

    Covering a light-emitting diode (LED) with quantum dots (QDs) can produce a broad spectrum of white light. However, current techniques for applying QDs to LEDs suffer from a high density of defects and a non-uniform distribution of QDs, which, respectively, diminish the efficiency and quality of emitted light. Oak Ridge National Laboratory (ORNL) has the unique capability to thermally anneal QD structures at extremely high power densities for very short durations. This process, called pulse thermal processing (PTP), reduces the number of point defects while maintaining the size and shape of the original QD nanostructure. Therefore, the efficiency of the QD wavelength conversion layer is improved without altering the emission spectrum defined by the size distribution of theQD nanoparticles. The current research uses a thermal model to predict annealing temperatures during PTP and demonstrates up to a 300% increase in photoluminescence for QDs on passive substrates.

  16. Simulation of quantum dots size and spacing effect for intermediate band solar cell application based on InAs quantum dots arrangement in GaAs

    SciTech Connect (OSTI)

    Hendra, P. I. B. Rahayu, F. Darma, Y.

    2014-03-24

    Intermediate band solar cell (IBSC) has become a promising technology in increasing solar cell efficiency. In this work we compare absorption coefficient profile between InAs quantum dots with GaAs bulk. We calculate the efficiency of GaAs bulk and GaAs doped with 2, 5, and 10 nm InAs quantum dot. Effective distances in quantum dot arrangement based on electron tunneling consideration were also calculated. We presented a simple calculation method with low computing power demand. Results showed that arrangement of quantum dot InAs in GaAs can increase solar cell efficiency from 23.9 % initially up to 60.4%. The effective distance between two quantum dots was found 2 nm in order to give adequate distance to prevent electron tunneling and wave functions overlap.

  17. ADVANCED CUTTINGS TRANSPORT STUDY

    SciTech Connect (OSTI)

    Stefan Miska; Troy Reed; Ergun Kuru

    2004-09-30

    The Advanced Cuttings Transport Study (ACTS) was a 5-year JIP project undertaken at the University of Tulsa (TU). The project was sponsored by the U.S. Department of Energy (DOE) and JIP member companies. The objectives of the project were: (1) to develop and construct a new research facility that would allow three-phase (gas, liquid and cuttings) flow experiments under ambient and EPET (elevated pressure and temperature) conditions, and at different angle of inclinations and drill pipe rotation speeds; (2) to conduct experiments and develop a data base for the industry and academia; and (3) to develop mechanistic models for optimization of drilling hydraulics and cuttings transport. This project consisted of research studies, flow loop construction and instrumentation development. Following a one-year period for basic flow loop construction, a proposal was submitted by TU to the DOE for a five-year project that was organized in such a manner as to provide a logical progression of research experiments as well as additions to the basic flow loop. The flow loop additions and improvements included: (1) elevated temperature capability; (2) two-phase (gas and liquid, foam etc.) capability; (3) cuttings injection and removal system; (4) drill pipe rotation system; and (5) drilling section elevation system. In parallel with the flow loop construction, hydraulics and cuttings transport studies were preformed using drilling foams and aerated muds. In addition, hydraulics and rheology of synthetic drilling fluids were investigated. The studies were performed under ambient and EPET conditions. The effects of temperature and pressure on the hydraulics and cuttings transport were investigated. Mechanistic models were developed to predict frictional pressure loss and cuttings transport in horizontal and near-horizontal configurations. Model predictions were compared with the measured data. Predominantly, model predictions show satisfactory agreements with the measured data. As a part of this project, instrumentation was developed to monitor cuttings beds and characterize foams in the flow loop. An ultrasonic-based monitoring system was developed to measure cuttings bed thickness in the flow loop. Data acquisition software controls the system and processes the data. Two foam generating devices were designed and developed to produce foams with specified quality and texture. The devices are equipped with a bubble recognition system and an in-line viscometer to measure bubble size distribution and foam rheology, respectively. The 5-year project is completed. Future research activities will be under the umbrella of Tulsa University Drilling Research Projects. Currently the flow loop is being used for testing cuttings transport capacity of aqueous and polymer-based foams under elevated pressure and temperature conditions. Subsequently, the effect of viscous sweeps on cuttings transport under elevated pressure and temperature conditions will be investigated using the flow loop. Other projects will follow now that the ''steady state'' phase of the project has been achieved.

  18. Fossil and synthetic fuels: miscellaneous. Part 1. Hearings before the Subcommittee on Fossil and Synthetic Fuels of the Committee on Energy and Commerce, House of Representatives, Ninety-Seventh Congress, First Session on Extension of IEA antitrust defense authorities, February 26, 1981, H. R. 2166, Department of Transportation authorization request, April 8, 1981, Gasohol usage in federal vehicles, July 30, 1981

    SciTech Connect (OSTI)

    Not Available

    1981-01-01

    Part I of the hearing record covers testimony relating to the extension of antitrust defense availability to the International Energy Agency (IEA); an authorization request by the Department of Transportation (DOT) to comply with pipeline safety regulations; and the administration's reluctance to promote gasohol use in federal vehicles. The first day's hearing included discussion of H.R. 2166, which extended the IEA authority by amending the Energy Policy and Conservation Act, and the testimony of four witnesses representing federal agencies involved in international affairs. On the second day, three DOT witnesses described pipeline-safety programs, enforcement, and procedures, with emphasis on the transport of liquefied natural gas. On the third day, nine witnesses representing gasohol-producing states, the US Army Equipment Research and Development Command, federal fleet services, and DOE examined the appropriateness and compliance record of Executive Order 12261 mandating gasohol for federally owned or leased vehicles. At issue was the need to convert Midwest grains to fuel at a time when oil is plentiful, the performance of alcohol fuels, and the administration's preference for working through the marketplace. Additional material submitted for the record follows each day's testimony. (DCK)

  19. Facile synthesis and photoluminescence mechanism of graphene quantum dots

    SciTech Connect (OSTI)

    Yang, Ping; Zhou, Ligang; Zhang, Shenli; Pan, Wei Shen, Wenzhong; Wan, Neng

    2014-12-28

    We report a facile hydrothermal synthesis of intrinsic fluorescent graphene quantum dots (GQDs) with two-dimensional morphology. This synthesis uses glucose, concentrate sulfuric acid, and deionized water as reagents. Concentrated sulfuric acid is found to play a key role in controlling the transformation of as-prepared hydrothermal products from amorphous carbon nanodots to well-crystallized GQDs. These GQDs show typical absorption characteristic for graphene, and have nearly excitation-independent ultraviolet and blue intrinsic emissions. Temperature-dependent PL measurements have demonstrated strong electron-electron scattering and electron-phonon interactions, suggesting a similar temperature behavior of GQDs to inorganic semiconductor quantum dots. According to optical studies, the ultraviolet emission is found to originate from the recombination of electron-hole pairs localized in the C=C bonds, while the blue emission is from the electron transition of sp{sup 2} domains.

  20. Resonant scattering of surface plasmon polaritons by dressed quantum dots

    SciTech Connect (OSTI)

    Huang, Danhong; Cardimona, Dave; Easter, Michelle; Gumbs, Godfrey; Maradudin, A. A.; Lin, Shawn-Yu; Zhang, Xiang

    2014-06-23

    The resonant scattering of surface plasmon-polariton waves (SPP) by embedded semiconductor quantum dots above the dielectric/metal interface is explored in the strong-coupling regime. In contrast to non-resonant scattering by a localized dielectric surface defect, a strong resonant peak in the spectrum of the scattered field is predicted that is accompanied by two side valleys. The peak height depends nonlinearly on the amplitude of SPP waves, reflecting the feedback dynamics from a photon-dressed electron-hole plasma inside the quantum dots. This unique behavior in the scattered field peak strength is correlated with the occurrence of a resonant dip in the absorption spectrum of SPP waves due to the interband photon-dressing effect. Our result on the scattering of SPP waves may be experimentally observable and applied to spatially selective illumination and imaging of individual molecules.

  1. Optical, electronic, and structural properties of uncoupled and close-packed arrays of InP quantum dots

    SciTech Connect (OSTI)

    Micic, O.I.; Jones, K.M.; Cahill, A.; Nozik, A.J.

    1998-12-03

    Solid films consisting of close-packed arrays of InP quantum dots have been prepared by slowly evaporating colloidal solutions of InP quantum dots. The diameters of the quantum dots were controlled to be between about 30 to 60 {angstrom}; size-selective precipitation yielded a size distribution of about 10% about the mean diameter. The arrays show regions of hexagonal order, as well as disordered regions. Oxide layers can form irreversibly on the quantum dot surface and limit the effectiveness of the size-selective precipitation. Photoluminescence spectra obtained from close-packed films of InP quantum dots formed from quantum dots with a single mean diameter and from a mixture of two quantum dot sizes show that energy transfer occurs from the photoexcited smaller quantum dots to the larger quantum dots. The efficiency of this energy transfer process is high.

  2. QCAD simulation and optimization of semiconductor double quantum dots

    SciTech Connect (OSTI)

    Nielsen, Erik; Gao, Xujiao; Kalashnikova, Irina; Muller, Richard Partain; Salinger, Andrew Gerhard; Young, Ralph Watson

    2013-12-01

    We present the Quantum Computer Aided Design (QCAD) simulator that targets modeling quantum devices, particularly silicon double quantum dots (DQDs) developed for quantum qubits. The simulator has three di erentiating features: (i) its core contains nonlinear Poisson, e ective mass Schrodinger, and Con guration Interaction solvers that have massively parallel capability for high simulation throughput, and can be run individually or combined self-consistently for 1D/2D/3D quantum devices; (ii) the core solvers show superior convergence even at near-zero-Kelvin temperatures, which is critical for modeling quantum computing devices; (iii) it couples with an optimization engine Dakota that enables optimization of gate voltages in DQDs for multiple desired targets. The Poisson solver includes Maxwell- Boltzmann and Fermi-Dirac statistics, supports Dirichlet, Neumann, interface charge, and Robin boundary conditions, and includes the e ect of dopant incomplete ionization. The solver has shown robust nonlinear convergence even in the milli-Kelvin temperature range, and has been extensively used to quickly obtain the semiclassical electrostatic potential in DQD devices. The self-consistent Schrodinger-Poisson solver has achieved robust and monotonic convergence behavior for 1D/2D/3D quantum devices at very low temperatures by using a predictor-correct iteration scheme. The QCAD simulator enables the calculation of dot-to-gate capacitances, and comparison with experiment and between solvers. It is observed that computed capacitances are in the right ballpark when compared to experiment, and quantum con nement increases capacitance when the number of electrons is xed in a quantum dot. In addition, the coupling of QCAD with Dakota allows to rapidly identify which device layouts are more likely leading to few-electron quantum dots. Very efficient QCAD simulations on a large number of fabricated and proposed Si DQDs have made it possible to provide fast feedback for design comparison and optimization.

  3. TRB-Transit Cooperative Research Program (TCRP): Case Studies...

    Open Energy Info (EERE)

    Transportation Research Board Focus Area: Transportation Resource Type: Publications, Lessons learnedbest practices, Case studiesexamples Website: www.trb.orgMainPublic...

  4. Density functional calculation of the structural and electronic properties of germanium quantum dots

    SciTech Connect (OSTI)

    Anas, M. M.; Gopir, G.

    2015-04-24

    We apply first principles density functional computational methods to study the structures, densities of states (DOS), and higher occupied molecular orbital (HOMO) lowest unoccupied molecular orbital (LUMO) gaps of selected free-standing Ge semiconductor quantum dots up to 1.8nm. Our calculations are performed using numerical atomic orbital approach where linear combination of atomic orbital was applied. The surfaces of the quantum dots was passivized by hydrogen atoms. We find that surface passivation does affect the electronic properties associated with the changes of surface state, electron localization, and the energy gaps of germanium nanocrystals as well as the confinement of electrons inside the quantum dots (QDs). Our study shows that the energy gaps of germanium quantum dots decreases with the increasing dot diameter. The size-dependent variations of the computed HOMO-LUMO gaps in our quantum dots model were found to be consistent with the effects of quantum confinement reported in others theoretical and experimental calculation.

  5. Excited-state spectroscopy of InP quantum dots

    SciTech Connect (OSTI)

    Bertram, D.; Micic, O.I.; Nozik, A.J.

    1998-02-01

    We have measured low-temperature size-selective photoluminescence excitation spectra of high-quality InP quantum dots prepared by collodial chemistry. A set of samples with mean emission energies in the range from 1.9 to 2.2 eV was investigated. All samples have a size distribution of about 10{percent}, resulting in an inhomogeneously broadened photoluminescence lineshape. Due to the finite size distribution, spectra were collected at different detection wavelengths to reveal the energies of the excited excitonic states. The size dependence of the quantization energies of InP nanoparticles was determined by measuring photoluminescence excitation at different detection energies within one sample. Up to eight excited-state transitions in a set of seven samples were observed, as the estimated quantum dot size was scanned from 1.8 to 4.0 nm. A comparison of the observed peaks with a six-band {bold k}{center_dot}{bold p} calculation is given. In contrast to the successful interpretation in the case of CdSe, no agreement between the calculated and the observed excited-state energies is achieved. {copyright} {ital 1998} {ital The American Physical Society}

  6. Size Dependence of Two-Photon Absorption in Semiconductor Quantum Dots

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Size Dependence of Two-Photon Absorption in Semiconductor Quantum Dots Citation Details In-Document Search Title: Size Dependence of Two-Photon Absorption in Semiconductor Quantum Dots Quantum confinement plays an important role in the optical properties of semiconductor quantum dots (QDs). In this work, we combine experiment and modeling to systematically investigate the size dependence of the degenerate two-photon absorption (TPA) of below-band-gap

  7. Formation of long-range ordered quantum dots arrays in amorphous matrix by ion beam irradiation

    SciTech Connect (OSTI)

    Buljan, M.; Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Dubcek, P.; Drazic, G.; Salamon, K.; Bernstorff, S.; Holy, V.

    2009-08-10

    We demonstrate the production of a well ordered three-dimensional array of Ge quantum dots in amorphous silica matrix. The ordering is achieved by ion beam irradiation and annealing of a multilayer film. Structural analysis shows that quantum dots nucleate along the direction of the ion beam used for irradiation, while the mutual distance of the quantum dots is determined by the diffusion properties of the multilayer material rather than the distances between traces of ions that are used for irradiation.

  8. Feasibility study for a transportation operations system cask maintenance facility

    SciTech Connect (OSTI)

    Rennich, M.J.; Medley, L.G.; Attaway, C.R.

    1991-01-01

    The US Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM) is responsible for the development of a waste management program for the disposition of spent nuclear fuel (SNF) and high-level waste (HLW). The program will include a transportation system for moving the nuclear waste from the sources to a geologic repository for permanent disposal. Specially designed casks will be used to safely transport the waste. The cask systems must be operated within limits imposed by DOE, the Nuclear Regulatory Commission (NRC), and the Department of Transportation (DOT). A dedicated facility for inspecting, testing, and maintaining the cask systems was recommended by the General Accounting Office (in 1979) as the best means of assuring their operational effectiveness and safety, as well as regulatory compliance. In November of 1987, OCRWM requested a feasibility study be made of a Cask Maintenance Facility (CMF) that would perform the required functions. 46 refs., 16 figs., 13 tabs.

  9. Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion

    Office of Scientific and Technical Information (OSTI)

    Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting Kundu, Janardan Los Alamos National Laboratory; Ghosh, Yagnaseni Los Alamos...

  10. Quantum-dot cluster-state computing with encoded qubits (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Quantum-dot cluster-state computing with encoded qubits Citation Details In-Document Search Title: Quantum-dot cluster-state computing with encoded qubits A class of architectures is advanced for cluster-state quantum computation using quantum dots. These architectures include using single and multiple dots as logical qubits. Special attention is given to supercoherent qubits introduced by Bacon et al. [Phys. Rev. Lett. 87, 247902 (2001)] for which we discuss the effects of

  11. Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion...

    Office of Scientific and Technical Information (OSTI)

    State Lighting Citation Details In-Document Search Title: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting You ...

  12. UltraDots Inc formely UltraPhotonics | Open Energy Information

    Open Energy Info (EERE)

    ) Place: Fremont, California Zip: CA 94539 Product: Nanotechnology company developing "quantum dot" technology for a range of energy, communications and medical applications....

  13. Charging dynamics of a floating gate transistor with site-controlled quantum dots

    SciTech Connect (OSTI)

    Maier, P. Hartmann, F.; Emmerling, M.; Schneider, C.; Hfling, S.; Kamp, M.; Worschech, L.

    2014-08-04

    A quantum dot memory based on a GaAs/AlGaAs quantum wire with site-controlled InAs quantum dots was realized by means of molecular beam epitaxy and etching techniques. By sampling of different gate voltage sweeps for the determination of charging and discharging thresholds, it was found that discharging takes place at short time scales of ?s, whereas several seconds of waiting times within a distinct negative gate voltage range were needed to charge the quantum dots. Such quantum dot structures have thus the potential to implement logic functions comprising charge and time dependent ingredients such as counting of signals or learning rules.

  14. Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion...

    Office of Scientific and Technical Information (OSTI)

    for LED based Solid State Lighting Citation Details In-Document Search Title: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based ...

  15. Thick-shell nanocrystal quantum dots (Patent) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Patent: Thick-shell nanocrystal quantum dots Citation Details In-Document Search Title: Thick-shell nanocrystal quantum dots Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes. Authors: Hollingsworth,

  16. Excited-State Relaxation in PbSe Quantum Dots

    SciTech Connect (OSTI)

    An, J. M.; Califano, M.; Franceschetti, A.; Zunger, A.

    2008-01-01

    In solids the phonon-assisted, nonradiative decay from high-energy electronic excited states to low-energy electronic excited states is picosecond fast. It was hoped that electron and hole relaxation could be slowed down in quantum dots, due to the unavailability of phonons energy matched to the large energy-level spacings ('phonon-bottleneck'). However, excited-state relaxation was observed to be rather fast ({le}1 ps) in InP, CdSe, and ZnO dots, and explained by an efficient Auger mechanism, whereby the excess energy of electrons is nonradiatively transferred to holes, which can then rapidly decay by phonon emission, by virtue of the densely spaced valence-band levels. The recent emergence of PbSe as a novel quantum-dot material has rekindled the hope for a slow down of excited-state relaxation because hole relaxation was deemed to be ineffective on account of the widely spaced hole levels. The assumption of sparse hole energy levels in PbSe was based on an effective-mass argument based on the light effective mass of the hole. Surprisingly, fast intraband relaxation times of 1-7 ps were observed in PbSe quantum dots and have been considered contradictory with the Auger cooling mechanism because of the assumed sparsity of the hole energy levels. Our pseudopotential calculations, however, do not support the scenario of sparse hole levels in PbSe: Because of the existence of three valence-band maxima in the bulk PbSe band structure, hole energy levels are densely spaced, in contradiction with simple effective-mass models. The remaining question is whether the Auger decay channel is sufficiently fast to account for the fast intraband relaxation. Using the atomistic pseudopotential wave functions of Pb{sub 2046}Se{sub 2117} and Pb{sub 260}Se{sub 249} quantum dots, we explicitly calculated the electron-hole Coulomb integrals and the P {yields} S electron Auger relaxation rate. We find that the Auger mechanism can explain the experimentally observed P {yields} S intraband decay time scale without the need to invoke any exotic relaxation mechanisms.

  17. Helms Research Group - Home

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

    Helms Group Home Research Members Publications Collaborations Connect Physical Organic Materials Chemistry Our research is devoted to understanding transport phenomena in mesostructured systems assembled from organic, organometallic, polymeric and nanocrystalline components. Enhanced capabilities relevant to energy, health, water, and food quality are enabled by our unique approaches to the modular design of their architectures and interfaces.

  18. Research Highlight

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

    North America, and South Asia) using the Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model (CTM) simulations were analyzed. ...

  19. International Conference on Surface Transportation System Resilience to Climate Change and Extreme Weather Events

    Broader source: Energy.gov [DOE]

    The conference will provide transportation professionals with information on emerging best practices and state of the art research results on how to adapt surface transportation networks to the...

  20. Transportation Beamline at the Advanced Photon Source | Argonne National

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

    Laboratory Transportation Beamline at the Advanced Photon Source Argonne's dedicated transportation research beamline at Argonne's Advanced Photon Source (APS) allows researchers to use the powerful X-ray beams created by the APS to penetrate materials and reveal details that cannot otherwise be seen. Transportation researchers use this tool to peer inside liquid sprays from fuel injectors for diesel engines. With a greater understanding of fuel spray composition, researchers have the

  1. Development of Onsite Transportation Safety Documents for Nevada Test Site

    SciTech Connect (OSTI)

    Frank Hand, Willard Thomas, Frank Sciacca, Manny Negrete, Susan Kelley

    2008-05-08

    Department of Energy (DOE) Orders require each DOE site to develop onsite transportation safety documents (OTSDs). The Nevada Test Site approach divided all onsite transfers into two groups with each group covered by a standalone OTSD identified as Non-Nuclear and Nuclear. The Non-Nuclear transfers involve all radioactive hazardous material in less than Hazard Category (HC)-3 quantities and all chemically hazardous materials. The Nuclear transfers involve all radioactive material equal to or greater than HC-3 quantities and radioactive material mated with high explosives regardless of quantity. Both OTSDs comply with DOE O 460.1B requirements. The Nuclear OTSD also complies with DOE O 461.1A requirements and includes a DOE-STD-3009 approach to hazard analysis (HA) and accident analysis as needed. All Nuclear OTSD proposed transfers were determined to be non-equivalent and a methodology was developed to determine if equivalent safety to a fully compliant Department of Transportation (DOT) transfer was achieved. For each HA scenario, three hypothetical transfers were evaluated: a DOT-compliant, uncontrolled, and controlled transfer. Equivalent safety is demonstrated when the risk level for each controlled transfer is equal to or less than the corresponding DOT-compliant transfer risk level. In this comparison the typical DOE-STD-3009 risk matrix was modified to reflect transportation requirements. Design basis conditions (DBCs) were developed for each non-equivalent transfer. Initial DBCs were based solely upon the amount of material present. Route-, transfer-, and site-specific conditions were evaluated and the initial DBCs revised as needed. Final DBCs were evaluated for each transfers packaging and its contents.

  2. Electrofuels: Versatile Transportation Energy Solutions

    SciTech Connect (OSTI)

    2010-07-01

    Electrofuels Project: ARPA-Es Electrofuels Project is using microorganisms to create liquid transportation fuels in a new and different way that could be up to 10 times more energy efficient than current biofuel production methods. ARPA-E is the only U.S. government agency currently funding research on Electrofuels.

  3. Grazing-incidence small-angle X-ray scattering: application to the study of quantum dot lattices

    SciTech Connect (OSTI)

    Buljan, Maja Radi?, Nikola; Bernstorff, Sigrid; Drai?, Goran; Bogdanovi?-Radovi?, Iva; Hol, Vclav

    2012-01-01

    The modelling of grazing-incidence small-angle X-ray scattering (GISAXS) from three-dimensional quantum dot lattices is described. The ordering of quantum dots in three-dimensional quantum dot lattices is investigated by grazing-incidence small-angle X-ray scattering (GISAXS). Theoretical models describing GISAXS intensity distributions for three general classes of lattices of quantum dots are proposed. The classes differ in the type of disorder of the positions of the quantum dots. The models enable full structure determination, including lattice type, lattice parameters, the type and degree of disorder in the quantum dot positions and the distributions of the quantum dot sizes. Applications of the developed models are demonstrated using experimentally measured data from several types of quantum dot lattices formed by a self-assembly process.

  4. The Complex Systems Landscape of Future Urban Transportation | Argonne

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

    National Laboratory The Complex Systems Landscape of Future Urban Transportation In an effort "to examine the nexus of energy and mobility for future transportation systems," the U.S. Department of Energy (DOE) has launched the Systems and Modeling for Accelerated Research in Transportation (SMART) Mobility consortium. By studying mobility as a system researchers can predict future trends, an invaluable asset to policymakers as they prepare for the future of transportation. This

  5. Layered insulator hexagonal boron nitride for surface passivation in quantum dot solar cell

    SciTech Connect (OSTI)

    Shanmugam, Mariyappan; Jain, Nikhil; Jacobs-Gedrim, Robin; Yu, Bin; Xu, Yang

    2013-12-09

    Single crystalline, two dimensional (2D) layered insulator hexagonal boron nitride (h-BN), is demonstrated as an emerging material candidate for surface passivation on mesoporous TiO{sub 2}. Cadmium selenide (CdSe) quantum dot based bulk heterojunction (BHJ) solar cell employed h-BN passivated TiO{sub 2} as an electron acceptor exhibits photoconversion efficiency ?46% more than BHJ employed unpassivated TiO{sub 2}. Dominant interfacial recombination pathways such as electron capture by TiO{sub 2} surface states and recombination with hole at valence band of CdSe are efficiently controlled by h-BN enabled surface passivation, leading to improved photovoltaic performance. Highly crystalline, confirmed by transmission electron microscopy, dangling bond-free 2D layered h-BN with self-terminated atomic planes, achieved by chemical exfoliation, enables efficient passivation on TiO{sub 2}, allowing electronic transport at TiO{sub 2}/h-BN/CdSe interface with much lower recombination rate compared to an unpassivated TiO{sub 2}/CdSe interface.

  6. Packaging and Transportation for Offsite Shipment of Materials of National Security Interest

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2010-12-20

    The purpose of this Order is to make clear that the packaging and transportation of all offsite shipments of materials of national security interest for DOE must be conducted in accordance with DOT and Nuclear Regulatory Commission (NRC) regulations that would be applicable to comparable commercial shipments, except where an alternative course of action is identified in this Order. Supersedes DOE O 461.1A.

  7. Statistical theory of Coulomb blockade oscillations: Quantum chaos in quantum dots

    SciTech Connect (OSTI)

    Jalabert, R.A.; Stone, A.D.; Alhassid, Y. (Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, Connecticut 06511 (United States))

    1992-06-08

    We develop a statistical theory of the amplitude of Coulomb blockade oscillations in semiconductor quantum dots based on the hypothesis that chaotic dynamics in the dot potential leads to behavior described by random-matrix theory. Breaking time-reversal symmetry is predicted to cause an experimentally observable change in the distribution of amplitudes. The theory is tested numerically and good agreement is found.

  8. Prediction of a strain-induced conduction-band minimum in embedded quantum dots

    SciTech Connect (OSTI)

    Williamson, A.J.; Zunger, A.; Canning, A.

    1998-02-01

    Free-standing InP quantum dots have previously been theoretically and experimentally shown to have a direct band gap across a large range of experimentally accessible sizes. We demonstrated that when these dots are embedded coherently within a GaP barrier material, the effects of quantum confinement in conjunction with coherent strain suggest there will be a critical diameter of dot ({approx}60 {Angstrom}), above which the dot is direct, type I, and below which it is indirect, type II. However, the strain in the system acts to produce another conduction state with an even lower energy, in which electrons are localized in small pockets at the interface between the InP dot and the GaP barrier. Since this conduction state is GaP X{sub 1c} derived and the highest occupied valence state is InP, {Gamma} derived, the fundamental transition is predicted to be indirect in both real and reciprocal space ({open_quotes}type II{close_quotes}) for all dot sizes. This effect is peculiar to the strained dot, and is absent in the freestanding dot. {copyright} {ital 1998} {ital The American Physical Society}

  9. Probing the size and environment induced phase transformation in CdSe quantum dots

    SciTech Connect (OSTI)

    Karakoti, Ajay S.; Sanghavi, Shail P.; Nachimuthu, Ponnusamy; Yang, Ping; Thevuthasan, Suntharampillai

    2011-11-17

    The structural and electronic properties of CdSe quantum dots in toluene and drop-casted on Si wafer were investigated by in-situ micro X-ray diffraction, X-ray photoelectron spectroscopy and UV-Vis absorption and emission spectroscopy. The in-situ micro diffraction data show that the CdSe quantum dots capped with TOPO or hexadecylamine (HDA) in toluene exhibit predominantly wurtzite crystal structure, which undergoes a phase transformation to zinc blende crystal structure following drop casting on Si and this phase transition increases with decreasing the size of the CdSe quantum dots. Decreasing the size of quantum dots also increases the Se vacancies that facilitate the phase transformation. The X-ray photoelectron spectra show a systematic increase in the core level binding energies of Cd 3d and Se 3d, the band gap and the Cd/Se ratio as the size of the quantum dots decreases from 6.6nm to 2.1nm. This is attributed to the quantum confinement of CdSe crystallites by the capping ligands in toluene which increases with decreasing the size of the quantum dots. However, drop-casting quantum dots on Si alter the density and arrangement of capping ligands and solvent molecules on the quantum dots which causes significant phase transformation.

  10. Activation of molecular catalysts using semiconductor quantum dots

    DOE Patents [OSTI]

    Meyer, Thomas J. (Chapel Hill, NC); Sykora, Milan (Los Alamos, NM); Klimov, Victor I. (Los Alamos, NM)

    2011-10-04

    Photocatalytic materials based on coupling of semiconductor nanocrystalline quantum dots (NQD) and molecular catalysts. These materials have capability to drive or catalyze non-spontaneous chemical reactions in the presence of visible radiation, ultraviolet radiation, or both. The NQD functions in these materials as a light absorber and charge generator. Following light absorption, the NQD activates a molecular catalyst adsorbed on the surface of the NQD via transfer of one or more charges (either electrons or electron-holes) from the NQD to the molecular catalyst. The activated molecular catalyst can then drive a chemical reaction. A photoelectrolytic device that includes such photocatalytic materials is also described.

  11. Electronic structure of nanocrystal quantum-dot quantumwells

    SciTech Connect (OSTI)

    Schrier, Joshua; Wang, Lin-Wang

    2006-06-26

    The electronic states of CdS/CdSe/CdS colloidal nanocrystalquantum-dot quantum wells are studied by large-scale pseudopotentiallocal density approximation (LDA) calculations. Using this approach, wedetermine the effects of CdS core size, CdSe well thickness, and CdSshell thickness on the band-edge wave functions, band-gap, andelectron-hole Coulomb interactions. We find the conduction-band wavefunction to be less confined to the CdSe well layer than predicted by kcdot p effective-mass theory, which accounts for the previous underestimation of the electron g factor.

  12. Photoluminescence-enhanced biocompatible quantum dots by phospholipid functionalization

    SciTech Connect (OSTI)

    Shi Yunfeng; He Peng Zhu Xinyuan

    2008-10-02

    A simple two-step strategy using phospholipid (PPL) to functionalize core/shell CdSe/ZnS quantum dots (QDs) has been described. The experimental data show that the use of S-H terminated PPL results not only in the high colloidal stability of core/shell CdSe/ZnS QDs in the aqueous phase, but also in the significant enhancement of photoluminescence. The degree of the enhancement is a function of the PPL-CdSe/ZnS QDs sample concentration. These results might be promising for future biological platform in new devices ranging from photovoltaic cells to biosensors and other devices.

  13. Ratiometric Sensing of Toxins using Quantum Dots | Argonne National

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

    Laboratory Ratiometric Sensing of Toxins using Quantum Dots December 4, 2015 Tweet EmailPrint Botulinum neurotoxin (BoNT) presents a significant hazard under numerous realistic scenarios. BoNT is the most toxic substance known. Current tests for BoNT are slow (2 days), lab-based, and complex. A new scheme offers quick, specific quantification by non-specialized personnel such as first responders in the field. The standard detection scheme for this fast-acting toxin is a lab-based mouse

  14. Computational modeling of electrophotonics nanomaterials: Tunneling in double quantum dots

    SciTech Connect (OSTI)

    Vlahovic, Branislav Filikhin, Igor

    2014-10-06

    Single electron localization and tunneling in double quantum dots (DQD) and rings (DQR) and in particular the localized-delocalized states and their spectral distributions are considered in dependence on the geometry of the DQDs (DQRs). The effect of violation of symmetry of DQDs geometry on the tunneling is studied in details. The cases of regular and chaotic geometries are considered. It will be shown that a small violation of symmetry drastically affects localization of electron and that anti-crossing of the levels is the mechanism of tunneling between the localized and delocalized states in DQRs.

  15. Transportation Emergency Preparedness Program

    Office of Environmental Management (EM)

    Stakeholders Forum 1 Planning for a Shipment Campaign Identifying Responders Needs National Transportation Stakeholders Forum Tom Clawson US Department of Energy Transportation...

  16. Water-soluble luminescent quantum dots and biomolecular conjugates thereof and related compositions and method of use

    DOE Patents [OSTI]

    Nie, Shuming (Bloomington, IN); Chan, Warren C. W. (Bloomington, IN); Emory, Steven R. (Los Alamos, NM)

    2002-01-01

    The present invention provides a water-soluble luminescent quantum dot, a biomolecular conjugate thereof and a composition comprising such a quantum dot or conjugate. Additionally, the present invention provides a method of obtaining a luminescent quantum dot, a method of making a biomolecular conjugate thereof, and methods of using a biomolecular conjugate for ultrasensitive nonisotopic detection in vitro and in vivo.

  17. Water-soluble luminescent quantum dots and biomolecular conjugates thereof and related compositions and methods of use

    DOE Patents [OSTI]

    Nie, Shuming; Chan, Warren C. W.; Emory, Stephen

    2007-03-20

    The present invention provides a water-soluble luminescent quantum dot, a biomolecular conjugate thereof and a composition comprising such a quantum dot or conjugate. Additionally, the present invention provides a method of obtaining a luminescent quantum dot, a method of making a biomolecular conjugate thereof, and methods of using a biomolecular conjugate for ultrasensitive nonisotopic detection in vitro and in vivo.

  18. Intermediate-band photosensitive device with quantum dots embedded in energy fence barrier

    DOE Patents [OSTI]

    Forrest, Stephen R. (Ann Arbor, MI); Wei, Guodan (Ann Arbor, MI)

    2010-07-06

    A plurality of layers of a first semiconductor material and a plurality of dots-in-a-fence barriers disposed in a stack between a first electrode and a second electrode. Each dots-in-a-fence barrier consists essentially of a plurality of quantum dots of a second semiconductor material embedded between and in direct contact with two layers of a third semiconductor material. Wave functions of the quantum dots overlap as at least one intermediate band. The layers of the third semiconductor material are arranged as tunneling barriers to require a first electron and/or a first hole in a layer of the first material to perform quantum mechanical tunneling to reach the second material within a respective quantum dot, and to require a second electron and/or a second hole in a layer of the first semiconductor material to perform quantum mechanical tunneling to reach another layer of the first semiconductor material.

  19. Charge-transfer dynamics in multilayered PbS and PbSe quantum dot architectures

    SciTech Connect (OSTI)

    Xu, F.; Ma, X.; Haughn, C. R.; Doty, M. F.; Cloutier, S. G.

    2014-02-03

    We demonstrate control of the charge transfer process in PbS and PbSe quantum dot assemblies. We first demonstrate efficient charge transfer from donor quantum dots to acceptor quantum dots in a multi-layer PbSe cascade structure. Then, we assemble type-I and type-II heterostructures using both PbS and PbSe quantum dots via careful control of the band alignment. In type-I structures, photo-generated carriers are transferred and localized in the smaller bandgap (acceptor) quantum dots, resulting in a significant luminescence enhancement. In contrast, a significant luminescence quenching and shorter emission lifetime confirms an efficient separation of photo-generated carriers in the type-II architecture.

  20. Analysis Insights, August 2015: Sustainable Transportation; NREL (National Renewable Energy Laboratory)

    SciTech Connect (OSTI)

    2015-08-01

    NREL Analysis Insights mines our body of analysis work to synthesize topical insights and key findings. In this issue, we examine transportation systems, alternative fuels, and implications of increasing electrification of transit. Moving people and goods from point A to B has never been easier, but our current transportation systems also take a toll on our environment. Transportation currently accounts for 71% of total U.S. petroleum use and 33% of the nation’s total carbon emissions. With new technology, can we make our transportation system cleaner and more cost effective? NREL is applying its analytical expertise and imagination to do just that. Solutions start with systems thinking. Connecting the dots between physical components - vehicles, fueling stations, and highways - and institutional components - traffic laws, regulations, and vehicle standards - helps illuminate solutions that address the needs of the transportation system's many stakeholders.

  1. Colloidal quantum dot solar cells on curved and flexible substrates

    SciTech Connect (OSTI)

    Kramer, Illan J.; Moreno-Bautista, Gabriel; Minor, James C.; Kopilovic, Damir; Sargent, Edward H.

    2014-10-20

    Colloidal quantum dots (CQDs) are semiconductor nanocrystals synthesized with, processed in, and deposited from the solution phase, potentially enabling low-cost, facile manufacture of solar cells. Unfortunately, CQD solar cell reports, until now, have only explored batch-processing methodssuch as spin-coatingthat offer limited capacity for scaling. Spray-coating could offer a means of producing uniform colloidal quantum dot films that yield high-quality devices. Here, we explore the versatility of the spray-coating method by producing CQD solar cells in a variety of previously unexplored substrate arrangements. The potential transferability of the spray-coating method to a roll-to-roll manufacturing process was tested by spray-coating the CQD active layer onto six substrates mounted on a rapidly rotating drum, yielding devices with an average power conversion efficiency of 6.7%. We further tested the manufacturability of the process by endeavoring to spray onto flexible substrates, only to find that spraying while the substrate was flexed was crucial to achieving champion performance of 7.2% without compromise to open-circuit voltage. Having deposited onto a substrate with one axis of curvature, we then built our CQD solar cells onto a spherical lens substrate having two axes of curvature resulting in a 5% efficient device. These results show that CQDs deposited using our spraying method can be integrated to large-area manufacturing processes and can be used to make solar cells on unconventional shapes.

  2. Transportation Organization and Functions

    Broader source: Energy.gov [DOE]

    Office of Packaging and Transportation list of organizations and functions, with a list of acronyms.

  3. Hydrogen Energy Storage for Grid and Transportation Services...

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

    ... Lipman, UC Berkeley, Transportation Sustainability Research Center Key Panel Questions: ... Sheraton Grand Lobby Cash bar, with food compliments of the Breakthrough ...

  4. National Alliance for Advanced Transportation Battery Cell Manufacture...

    Open Energy Info (EERE)

    Manufacture Product: US-based consortium formed to research, develop, and mass produce lithium ion batteries. References: National Alliance for Advanced Transportation Battery Cell...

  5. Influence of Topological Spin Fluctuations on Charge Transport

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

    Influence of Topological Spin Fluctuations on Charge Transport Print Layered transition metal oxides are the focus of intense research efforts because they might clarify the...

  6. Transportation technology R&D-Steve Ciatti | Argonne National...

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

    technology R&D-Steve Ciatti Share Description Argonne researcher Steve Ciatti talks about emerging technologies in transportation, as well as the current technology being developed...

  7. Sandia Energy - CRF Researchers Received "Best Paper" Award for...

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

    Conference Home Energy Transportation Energy CRF Facilities Partnership News Energy Efficiency News & Events Sensors & Optical Diagnostics CRF Researchers Received "Best...

  8. Innovation Impact: Breakthrough Research Results (Brochure)

    SciTech Connect (OSTI)

    Not Available

    2013-07-01

    The Innovation Impact brochure captures key breakthrough results across NREL's primary areas of renewable energy and energy efficiency research: solar, wind, bioenergy, transportation, buildings, analysis, and manufacturing technologies.

  9. Effect of swift heavy ion irradiation on bare and coated ZnS quantum dots

    SciTech Connect (OSTI)

    Chowdhury, S. Hussain, A.M.P.; Ahmed, G.A.; Singh, F.; Avasthi, D.K.; Choudhury, A.

    2008-12-01

    The present study compares structural and optical modifications of bare and silica (SiO{sub 2}) coated ZnS quantum dots under swift heavy ion (SHI) irradiation. Bare and silica coated ZnS quantum dots were prepared following an inexpensive chemical route using polyvinyl alcohol (PVA) as the dielectric host matrix. X-ray diffraction (XRD) and transmission electron microscopy (TEM) study of the samples show the formation of almost spherical ZnS quantum dots. The UV-Vis absorption spectra reveal blue shift relative to bulk material in absorption energy while photoluminescence (PL) spectra suggests that surface state and near band edge emissions are dominating in case of bare and coated samples, respectively. Swift heavy ion irradiation of the samples was carried out with 160 MeV Ni{sup 12+} ion beam with fluences 10{sup 12} to 10{sup 13} ions/cm{sup 2}. Size enhancement of bare quantum dots after irradiation has been indicated in XRD and TEM analysis of the samples which has also been supported by optical absorption spectra. However similar investigations on irradiated coated quantum dots revealed little change in quantum dot size and emission. The present study thus shows that the coated ZnS quantum dots are stable upon SHI irradiation compared to the bare one.

  10. Tuning the properties of Ge-quantum dots superlattices in amorphous silica matrix through deposition conditions

    SciTech Connect (OSTI)

    Pinto, S. R. C.; Ramos, M. M. D.; Gomes, M. J. M.; Buljan, M.; Chahboun, A.; Roldan, M. A.; Molina, S. I.; Bernstorff, S.; Varela, M.; Pennycook, S. J.; Barradas, N. P.; Alves, E.

    2012-04-01

    In this work, we investigate the structural properties of Ge quantum dot lattices in amorphous silica matrix, prepared by low-temperature magnetron sputtering deposition of (Ge+SiO{sub 2})/SiO{sub 2} multilayers. The dependence of quantum dot shape, size, separation, and arrangement type on the Ge-rich (Ge + SiO{sub 2}) layer thickness is studied. We show that the quantum dots are elongated along the growth direction, perpendicular to the multilayer surface. The size of the quantum dots and their separation along the growth direction can be tuned by changing the Ge-rich layer thickness. The average value of the quantum dots size along the lateral (in-plane) direction along with their lateral separation is not affected by the thickness of the Ge-rich layer. However, the thickness of the Ge-rich layer significantly affects the quantum dot ordering. In addition, we investigate the dependence of the multilayer average atomic composition and also the quantum dot crystalline quality on the deposition parameters.

  11. Interagency cooperation in the development of a cost-effective transportation and disposal solution for vitrified radium bearing material

    SciTech Connect (OSTI)

    Smith, M.L.; Nixon, D.A.; Stone, T.J.; Tope, W.G.; Vogel, R.A.; Allen, R.B.; Schofield, W.D.

    1996-02-01

    Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3 waste, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, shielding requirements, packaging, and transportation alternatives was completed to identify the safest, most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-resonably-achievable principles, and material handling costs were factored into the recommended approach. Through cooperative work between the U.S. Department of Energy (DOE) and the U.S. Department of Transportation (DOT), the vitrified K-65 and Silo 3 radioactive material will be classified consistent with the regulations promulgated by DOT in the September 28, 1995 Federal Register. These new regulations adopt International Atomic Energy Agency language to promote a consistent approach for the transportation and management of radioactive material between the international community and the DOT. Use of the new regulations allows classification of the vitrified radioactive material from the Fernald silos under the designation of low specific activity-II and allows the development of a container that is optimized to maximize payload while minimizing internal void space, external surface radiation levels, and external volume. This approach minimizes the required number of containers and shipments, and the related transportation and disposal costs.

  12. Enhanced performance of branched TiO{sub 2} nanorod based Mn-doped CdS and Mn-doped CdSe quantum dot-sensitized solar cell

    SciTech Connect (OSTI)

    Kim, Soo-Kyoung; Gopi, Chandu V. V. M.; Lee, Jae-Cheol; Kim, Hee-Je

    2015-04-28

    TiO{sub 2} branched nanostructures could be efficient as photoanodes for quantum dot-sensitized solar cells (QDSCs) due to their large surface area for QD deposition. In this study, Mn-doped CdS/Mn-doped CdSe deposited branched TiO{sub 2} nanorods were fabricated to enhance the photovoltaic performance of QDSCs. Mn doping in CdS and CdSe retards the recombination losses of electrons, while branched TiO{sub 2} nanorods facilitate effective electron transport and compensate for the low surface area of the nanorod structure. As a result, the charge-transfer resistance (R{sub CT}), electron lifetime (?{sub e}), and the amount of QD deposition were significantly improved with branched TiO{sub 2} nanorod based Mn-doped CdS/Mn-doped CdSe quantum dot-sensitized solar cell.

  13. DOT Beyond Traffic Smart City Challenge | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    4, 2016 3:00PM EST U.S. Department of Transportation The U.S. Department of Transportation is accepting applications for the Smart City Challenge to one mid-sized city that can demonstrate how advanced data and intelligent transportation system technologies and applications can be used to reduce congestion, protect the environment, respond to climate change, and support economic vitality. Eligible applicants include state, local, and tribal governments.

  14. Paul Blom: Research Director, Max Planck Institute for Polymer...

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

    PM Paul Blom Research Director, Max Planck Institute for Polymer Research Transport and Recombination in Polymer:fullerene bulk Heterojunction Solar Cells January 22, 2014 |...

  15. Passive solar buildings research

    SciTech Connect (OSTI)

    Balcomb, J.D.

    1992-12-31

    This chapter covers research advances in passive solar buildings research during the time span from 1982 through 1991. These advances fall within the following categories: (1) short-term energy monitoring, (2) heat transport by natural convection within buildings, and (3) design guidelines and design tools. In short-term energy monitoring, a simulation model of the building is calibrated, based on data taken in a 3-day test. The method accurately predicts performance over an extended period. Heat transport through doorways is characterized for complex situations that arise in passive solar buildings. Simple concepts and models adequately describe the energy transport in many situations of interest. In a new approach, design guidelines are automatically generated for any specific locality. Worksheets or an accompanying computer program allow the designer to quickly and accurately evaluate performance and investigate design alternatives. 29 refs., 19 figs., 2 tabs.

  16. Radiation transport. Progress report, October 1, 1982-March 31, 1983

    SciTech Connect (OSTI)

    O'Dell, R.D.

    1984-05-01

    Research and development progress in radiation transport by the Los Alamos National Laboratory's Group X-6 for the first half of FY 83 is reported. Included are tasks in the areas of Fission Reactor Neutronics, Deterministic Transport Methods, and Monte Carlo Radiation Transport.

  17. Far off-resonant coupling between photonic crystal microcavity and single quantum dot with resonant excitation

    SciTech Connect (OSTI)

    Banihashemi, Mehdi; Ahmadi, Vahid, E-mail: v-ahmadi@modares.ac.ir [Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, P.O. Box 14115-194 (Iran, Islamic Republic of)] [Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, P.O. Box 14115-194 (Iran, Islamic Republic of); Nakamura, Tatsuya; Kojima, Takanori; Kojima, Kazunobu; Noda, Susumu [Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)] [Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2013-12-16

    In this paper, we experimentally demonstrate that with sub-nanowatt coherent s-shell excitation of a single InAs quantum dot, off-resonant coupling of 4.1?nm is possible between L3 photonic crystal microcavity and the quantum dot at 50?K. This resonant excitation reduces strongly the effect of surrounding charges to quantum dot, multiexciton complexes and pure dephasing. It seems that this far off-resonant coupling is the result of increased number of acoustical phonons due to high operating temperature of 50?K. The 4.1?nm detuning is the largest amount for this kind of coupling.

  18. Direct Observation of Energy-Gap Scaling Law in CdSe Quantum Dots with Positrons

    SciTech Connect (OSTI)

    Denison, Arthur Blanchard; Weber, M. H.; Lynn, K. G.; Barbiellini, B.; Sterne, P. A.

    2002-07-01

    CdSe quantum dot samples with sizes in the range of 1.8~6 nm in diameter were examined by positron annihilation spectroscopy. The results were compared to data obtained for single-crystal bulk CdSe. Evidence is provided that the positrons annihilate within the nanospheres. The annihilation line shape shows a smearing at the boundary of the Jones zone proportional to the widening of the band gap due to a reduction in the size of the quantum dots. The data confirm that the change in the band gap is inversely proportional to the square of the quantum dot diameter.

  19. The use of bulk states to accelerate the band edge statecalculation of a semiconductor quantum dot

    SciTech Connect (OSTI)

    Vomel, Christof; Tomov, Stanimire Z.; Wang, Lin-Wang; Marques,Osni A.; Dongarra, Jack J.

    2006-05-10

    We present a new technique to accelerate the convergence of the folded spectrum method in empirical pseudopotential band edge state calculations for colloidal quantum dots. We use bulk band states of the materials constituent of the quantum dot to construct initial vectors and a preconditioner. We apply these to accelerate the convergence of the folded spectrum method for the interior states at the top of the valence and the bottom of the conduction band. For large CdSe quantum dots, the number of iteration steps until convergence decreases by about a factor of 4 compared to previous calculations.

  20. R&D Magazine: Windows into Solar Power Sources with Quantum Dots

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

    R&D Magazine: Windows into Solar Power Sources with Quantum Dots August 30, 2015 R&D Magazine: Windows into Solar Power Sources with Quantum Dots A luminescent solar concentrator is an emerging sunlight harvesting technology that has the potential to disrupt the way we think about energy: It could turn any window into a daytime power source. "In these devices, a fraction of light transmitted through the window is absorbed by nano-sized particles (semiconductor quantum dots)

  1. Enhanced single photon emission from positioned InP/GaInP quantum dots

    Office of Scientific and Technical Information (OSTI)

    coupled to a confined Tamm-plasmon mode (Journal Article) | SciTech Connect Enhanced single photon emission from positioned InP/GaInP quantum dots coupled to a confined Tamm-plasmon mode Citation Details In-Document Search Title: Enhanced single photon emission from positioned InP/GaInP quantum dots coupled to a confined Tamm-plasmon mode We report on the enhancement of the spontaneous emission in the visible red spectral range from site-controlled InP/GaInP quantum dots by resonant coupling

  2. Red light-emitting diodes based on InP/GaP quantum dots

    SciTech Connect (OSTI)

    Hatami, F.; Lordi, V.; Harris, J.S.; Kostial, H.; Masselink, W.T.

    2005-05-01

    The growth, fabrication, and device characterization of InP quantum-dot light-emitting diodes based on GaP are described and discussed. The diode structures are grown on gallium phosphide substrates using gas-source molecular-beam epitaxy and the active region of the diode consists of self-assembled InP quantum dots embedded in a GaP matrix. Red electroluminescence originating from direct band-gap emission from the InP quantum dots is observed at low temperatures.With increasing temperature, however, the emission line shifts to the longer wavelength. The emission light is measured to above room temperature.

  3. R&D Magazine: Windows into Solar Power Sources with Quantum Dots

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

    R&D Magazine: Windows into Solar Power Sources with Quantum Dots R&D Magazine: Windows into Solar Power Sources with Quantum Dots A luminescent solar concentrator is an emerging sunlight harvesting technology that has the potential to disrupt the way we think about energy: It could turn any window into a daytime power source. August 30, 2015 R&D Magazine: Windows into Solar Power Sources with Quantum Dots A luminescent solar concentrator is an emerging sunlight harvesting technology

  4. Synthesis of Non-blinking Semiconductor Quantum Dots Emitting in the

    Office of Scientific and Technical Information (OSTI)

    Near-Infrared (Conference) | SciTech Connect Synthesis of Non-blinking Semiconductor Quantum Dots Emitting in the Near-Infrared Citation Details In-Document Search Title: Synthesis of Non-blinking Semiconductor Quantum Dots Emitting in the Near-Infrared Our previous work demonstrates that Quasi-Type II CdSe/CdS core-shell quantum dots with thick shells (3-5 nm) exhibit unique photophysical characteristics, including improved chemical robustness over typical thin-shelled core/shell systems

  5. On-chip generation and guiding of quantum light from a site-controlled quantum dot

    SciTech Connect (OSTI)

    Jamil, Ayesha; Farrer, Ian; Griffiths, Jonathan P.; Jones, Geb A. C.; Ritchie, David A.; Skiba-Szymanska, Joanna; Kalliakos, Sokratis; Ward, Martin B.; Ellis, David J. P.; Shields, Andrew J.; Schwagmann, Andre; Brody, Yarden; Cambridge Research Laboratory, Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ

    2014-03-10

    We demonstrate the emission and routing of single photons along a semiconductor chip originating from carrier recombination in an actively positioned InAs quantum dot. Devicescale arrays of quantum dots are formed by a twostep regrowth process. We precisely locate the propagating region of a unidirectional photonic crystal waveguide with respect to the quantum dot nucleation site. Under pulsed optical excitation, the multiphoton emission probability from the waveguide's exit is 12%??5% before any background correction. Our results are a major step towards the deterministic integration of a quantum emitter with the waveguiding components of photonic quantum circuits.

  6. Director Dot Harris Inspires Girls at DigiGirlz Day Event | Department of

    Office of Environmental Management (EM)

    Energy Director Dot Harris Inspires Girls at DigiGirlz Day Event Director Dot Harris Inspires Girls at DigiGirlz Day Event March 3, 2015 - 4:38pm Addthis Director Harris engages with DigiGirlz (Middle Tennessee High School students) Director Harris engages with DigiGirlz (Middle Tennessee High School students) During the 3rd Annual DigiGirlz Day event held in Nashville, TN on Saturday, February, 28, 2015, Dot Harris, Director of DOE's Office of Economic Impact and Diversity, delivered an

  7. Secure Transportation Management

    SciTech Connect (OSTI)

    Gibbs, P. W.

    2014-10-15

    Secure Transport Management Course (STMC) course provides managers with information related to procedures and equipment used to successfully transport special nuclear material. This workshop outlines these procedures and reinforces the information presented with the aid of numerous practical examples. The course focuses on understanding the regulatory framework for secure transportation of special nuclear materials, identifying the insider and outsider threat(s) to secure transportation, organization of a secure transportation unit, management and supervision of secure transportation units, equipment and facilities required, training and qualification needed.

  8. Interaction of graphene quantum dots with bulk semiconductor surfaces

    SciTech Connect (OSTI)

    Mohapatra, P. K.; Singh, B. P.; Kushavah, Dushyant; Mohapatra, J.

    2015-05-15

    Highly luminescent graphene quantum dots (GQDs) are synthesized through thermolysis of glucose. The average lateral size of the synthesized GQDs is found to be ?5 nm. The occurrence of D and G band at 1345 and 1580 cm{sup ?1} in Raman spectrum confirms the presence of graphene layers. GQDs are mostly consisting of 3 to 4 graphene layers as confirmed from the AFM measurements. Photoluminescence (PL) measurement shows a distinct broadening of the spectrum when GQDs are on the semiconducting bulk surface compared to GQDs in water. The time resolved PL measurement shows a significant shortening in PL lifetime due to the substrate interaction on GQDs compared to the GQDs in solution phase.

  9. Quantum Dot Solar Cells with Multiple Exciton Generation

    SciTech Connect (OSTI)

    Hanna, M. C.; Beard, M. C.; Johnson, J. C.; Murphy, J.; Ellingson, R. J.; Nozik, A. J.

    2005-11-01

    We have measured the quantum yield of the multiple exciton generation (MEG) process in quantum dots (QDs) of the lead-salt semiconductor family (PbSe, PbTe, and PbS) using fs pump-probe transient absorption measurements. Very high quantum yields (up to 300%) for charge carrier generation from MEG have been measured in all of the Pb-VI QDs. We have calculated the potential maximum performance of various MEG QD solar cells in the detailed balance limit. We examined a two-cell tandem PV device with singlet fission (SF), QD, and normal dye (N) absorbers in the nine possible series-connected combinations to compare the tandem combinations and identify the combinations with the highest theoretical efficiency. We also calculated the maximum efficiency of an idealized single-gap MEG QD solar cell with M multiplications and its performance under solar concentration.

  10. 49 CFR Parts 171-177: Hazardous Materials Regulations (DOT)

    Broader source: Energy.gov [DOE]

    The U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration regulates the transport of hazardous materials through Title 49 of the Code of Federal Regulations (49 CFR), Subchapter C, "Hazardous Materials Regulations." Parts 171-177 provide general information on hazardous materials and regulation for their packaging and their shipment by rail, air, vessel, and public highway.

  11. Transportation Management Workshop: Proceedings

    SciTech Connect (OSTI)

    Not Available

    1993-10-01

    This report is a compilation of discussions presented at the Transportation Management Workshop held in Gaithersburg, Maryland. Topics include waste packaging, personnel training, robotics, transportation routing, certification, containers, and waste classification.

  12. Packaging and Transportation Safety

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1995-09-27

    Establishes safety requirements for the proper packaging and transportation of offsite shipments and onsite transfers of hazardous materials andor modal transport. Cancels DOE 1540.2 and DOE 5480.3

  13. Packaging and Transportation Safety

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1995-09-27

    Establishes safety requirements for the proper packaging and transportation of Department of Energy (DOE) offsite shipments and onsite transfers of hazardous materials and for modal transport. Canceled by DOE 460.1A

  14. Packaging and Transportation Safety

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1996-10-02

    Establishes safety requirements for the proper packaging and transportation of Department of Energy (DOE) offsite shipments and onsite transfers of hazardous materials and for modal transport. Cancels DOE O 460.1.

  15. Transportation Energy Futures Study

    Broader source: Energy.gov [DOE]

    Transportation accounts for 71% of total U.S. petroleum consumption and 33% of total greenhouse gas emissions. The Transportation Energy Futures (TEF) study examines underexplored oil-savings and...

  16. Packaging and Transportation Safety

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2010-05-14

    The order establishes safety requirements for the proper packaging and transportation of DOE, including NNSA, offsite shipments and onsite transfers of radioactive and other hazardous materials and for modal transportation. Supersedes DOE O 460.1B.

  17. Research | NEES - EFRC | University of Maryland Energy Frontier Research

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

    Center Research NEES Mission NEES EFRC Research Overview NEES EFRC Research Overview To reveal scientific insights and design principles that enable a next-generation electrical energy storage technology based on dense mesoscale architectures of multifunctional nanostructures. The Challenge As demand for electrical energy storage (EES) reaches a critical point with increasing applications in transportation, grid storage and usage of renewable sources, energy research community seeks to

  18. TxDOT - Right of Way Forms webpage | Open Energy Information

    Open Energy Info (EERE)

    Right of Way Forms webpage Jump to: navigation, search OpenEI Reference LibraryAdd to library Web Site: TxDOT - Right of Way Forms webpage Abstract This webpage provides the...

  19. Mechanism of lateral ordering of InP dots grown on InGaP layers

    SciTech Connect (OSTI)

    Bortoleto, J.R.R.; Gutierrez, H.R.; Cotta, M.A.; Bettini, J.

    2005-07-04

    The mechanisms leading to the spontaneous formation of a two-dimensional array of InP/InGaP dots grown by chemical-beam epitaxy are discussed. Samples where the InGaP buffer layer was grown at different conditions were characterized by transmission electron microscopy. Our results indicate that a periodic strain field related to lateral two-dimensional compositional modulation in the InGaP buffer layer determines the dot nucleation positions during InP growth. Although the periodic strain field in the InGaP is large enough to align the InP dots, both their shape and optical properties are effectively unaltered. This result shows that compositional modulation can be used as a tool for in situ dot positioning.

  20. Quantum Dots Promise to Significantly Boost Solar Cell Efficiencies (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-08-01

    In the search for a third generation of solar-cell technologies, a leading candidate is the use of 'quantum dots' -- tiny spheres of semiconductor material measuring only about 2-10 billionths of a meter in diameter. Quantum dots have the potential to dramatically increase the efficiency of converting sunlight into energy -- perhaps even doubling it in some devices -- because of their ability to generate more than one bound electron-hole pair, or exciton, per incoming photon. NREL has produced quantum dots using colloidal suspensions; then, using molecular self-assembly, they have been fabricated into the first-ever quantum-dot solar cells. While these devices operate with only 4.4% efficiency, they demonstrate the capability for low-cost manufacturing.

  1. Theoretical study of intraband optical transitions in conduction band of dot-in-a-well system

    SciTech Connect (OSTI)

    Chaganti, Venkata R.; Apalkov, Vadym

    2014-02-15

    We study numerically absorption optical spectra of n-doped InAs/In{sub 015}Ga{sub 085}As/GaAs quantum dot-in-a-well systems. The absorption spectra are mainly determined by the size of a quantum dot and have weak dependence on the thickness of quantum well and position of the dot in a well. The dot-in-a-well system is sensitive to both in-plane and out-of-plane polarizations of the incident light with much stronger absorption intensities for the in-plane-polarized light. The absorption spectrum of in-plane-polarized light has also a multi-peak structure with two or three peaks of comparable intensities, while the absorption spectrum of out-of-plane polarized light has a single well-pronounced peak.

  2. Mastermind Session: Connecting the Dots Between the Real Estate Market and Residential Energy Efficiency

    Broader source: Energy.gov [DOE]

    Better Buildings Residential Network Program Sustainability Series Mastermind Call: Connecting the Dots Between the Real Estate Market and Residential Energy Efficiency Featuring Host Rich Dooley, Arlington County, VA, Call Slides and Discussion Summary, August 14, 2014.

  3. Water Transport Within the STack: Water Transport Exploratory...

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

    Within the STack: Water Transport Exploratory Studies Water Transport Within the STack: Water Transport Exploratory Studies Part of a 100 million fuel cell award announced by DOE ...

  4. Transportation Storage Interface

    Office of Environmental Management (EM)

    of Future Extended Storage and Transportation Transportation-Storage Interface James Rubenstone Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission National Transportation Stakeholders Forum May 2012 ♦ Knoxville, Tennessee Overview * Changing policy environment * Regulatory framework-current and future * Extended storage and transportation-technical information needs * Next Steps 2 Current Policy Environment * U.S. national policy for disposition of spent

  5. Probing Interfacial Electronic States in CdSe Quantum Dots using Second Harmonic Generation Spectroscopy

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

    Doughty, Benjamin L; Ma, Yingzhong; Shaw, Robert W

    2015-01-01

    Understanding and rationally controlling the properties of nanomaterial surfaces is a rapidly expanding field of research due to the dramatic role they play on the optical and electronic properties vital to light harvesting, emitting and detection technologies. This information is essential to the continued development of synthetic approaches designed to tailor interfaces for optimal nanomaterial based device performance. In this work, closely spaced electronic excited states in model CdSe quantum dots (QDs) are resolved using second harmonic generation (SHG) spectroscopy, and the corresponding contributions from surface species to these states are assessed. Two distinct spectral features are observed in themore » SHG spectra, which are not readily identified in linear absorption and photoluminescence excitation spectra. These features include a weak band at 395 6 nm, which coincides with transitions to the 2S1/2 1Se state, and a much more pronounced band at 423 4 nm arising from electronic transitions to the 1P3/2 1Pe state. Chemical modification of the QD surfaces through oxidation resulted in disappearance of the SHG band corresponding to the 1P3/2 1Pe state, indicating prominent surface contributions. Signatures of deep trap states localized on the surfaces of the QDs are also observed. We further find that the SHG signal intensities depend strongly on the electronic states being probed and their relative surface contributions, thereby offering additional insight into the surface specificity of SHG signals from QDs.« less

  6. InP quantum dots: Electronic structure, surface effects, and the redshifted emission

    SciTech Connect (OSTI)

    Fu, H.; Zunger, A.

    1997-07-01

    We present pseudopotential plane-wave electronic-structure calculations on InP quantum dots in an effort to understand quantum confinement and surface effects and to identify the origin of the long-lived and redshifted luminescence. We find that (i) unlike the case in small GaAs dots, the lowest unoccupied state of InP dots is the {Gamma}{sub 1c}-derived direct state rather than the X{sub 1c}-derived indirect state and (ii) unlike the prediction of {bold k}{center_dot}{bold p} models, the highest occupied state in InP dots has a 1sd-type envelope function rather than a (dipole-forbidden) 1pf envelope function. Thus explanations (i) and (ii) to the long-lived redshifted emission in terms of an orbitally forbidden character can be excluded. Furthermore, (iii) fully passivated InP dots have no surface states in the gap. However, (iv) removal of the anion-site passivation leads to a P dangling bond (DB) state just above the valence band, which will act as a trap for photogenerated holes. Similarly, (v) removal of the cation-site passivation leads to an In dangling-bond state below the conduction band. While the energy of the In DB state depends only weakly on quantum size, its radiative lifetime increases with quantum size. The calculated {approximately}300-meV redshift and the {approximately}18 times longer radiative lifetime relative to the dot-interior transition for the 26-{Angstrom} dot with an In DB are in good agreement with the observations of full-luminescence experiments for unetched InP dots. Yet, (vi) this type of redshift due to surface defect is inconsistent with that measured in {ital selective} excitation for HF-etched InP dots. (vii) The latter type of ({open_quotes}resonant{close_quotes}) redshift is compatible with the calculated {ital screened} singlet-triplet splitting in InP dots, suggesting that the slow emitting state seen in selective excitation could be a triplet state. {copyright} {ital 1997} {ital The American Physical Society}

  7. Quantum DotBridgeFullerene Heterodimers with Controlled Photoinduced Electron Transfer

    SciTech Connect (OSTI)

    Cotlet, M.; Xu, Z.

    2011-06-27

    A series of donor-bridge-acceptor systems in the form of core/shell CdSe/ZnS quantum dot-bridge-fullerene heterodimers (see picture) with varying bridge length and varying quantum dot size were self-assembled by a surface-based stepwise method to demonstrate control of the rate and of the magnitude of fluctuations of photoinduced electron transfer at the single-molecule level.

  8. Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion

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

    Phosphor for LED based Solid State Lighting (Technical Report) | SciTech Connect Technical Report: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting Citation Details In-Document Search Title: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting Authors: Kundu, Janardan [1] ; Ghosh, Yagnaseni [1] ; Dennis, Allison M. [1] ; Htoon, Han [1] ; Hollingsworth, Jennifer A

  9. Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion

    Office of Scientific and Technical Information (OSTI)

    Phosphor for LED based Solid State Lighting (Technical Report) | SciTech Connect Technical Report: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting Citation Details In-Document Search Title: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting Authors: Kundu, Janardan [1] ; Ghosh, Yagnaseni [1] ; Dennis, Allison M. [1] ; Htoon, Han [1] ; Hollingsworth, Jennifer A

  10. Overview of DOE - DOT December 2009 CNG and Hydrogen Fuels Workshop |

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

    Department of Energy - DOT December 2009 CNG and Hydrogen Fuels Workshop Overview of DOE - DOT December 2009 CNG and Hydrogen Fuels Workshop These slides were presented at the Onboard Storage Tank Workshop on April 29, 2010. PDF icon overview_doedot_ostw.pdf More Documents & Publications Workshop Notes from ""Compressed Natural Gas and Hydrogen Fuels: Lessons Learned for the Safe Deployment of Vehicles"" Workshop, December 10-11, 2009 Safety and Regulatory Structure

  11. "Giant" nanocrystal quantum dots for light-emission applications

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect "Giant" nanocrystal quantum dots for light-emission applications Citation Details In-Document Search Title: "Giant" nanocrystal quantum dots for light-emission applications Authors: Hollingsworth, Jennifer A. [1] + Show Author Affiliations Los Alamos National Laboratory Publication Date: 2013-02-15 OSTI Identifier: 1063241 Report Number(s): LA-UR-13-21028 DOE Contract Number: AC52-06NA25396 Resource Type: Conference Resource Relation:

  12. Helena Chum - Research Fellow | NREL

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

    Helena Chum - Research Fellow Photo of Helena Chum Research Fellows Dr. Helena Chum is a Research Fellow in the National Bioenergy Center at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) and a member of the NREL Research Fellows Council that reports to the Science and Technology Deputy Director. Her expertise is in renewable fuels, transportation systems, and international renewable energy activities including agriculture, forestry, bioenergy, bioproducts, biofuels,

  13. Research | JCESR

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

    charge transfer and transport, and developmentutilization of novel computational and measurement techniques for all relevant time and length scales. The National Mission Learn...

  14. Research Highlight

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

    Under the Convention on Long-range Transboundary Air Pollution (LRTAP), the task force on Hemispheric Transport of Air Pollution (HTAP) was established to develop a fuller ...

  15. Advanced Hydrogen Transport Membrane for Coal Gasification

    Office of Scientific and Technical Information (OSTI)

    Hydrogen Transport Membrane for Coal Gasification DE-FE0004908 Praxair, Inc. Advanced Hydrogen Transport Membrane for Coal Gasification Final Report October 2010 - September 2015 Joseph Schwartz and David Makuch Praxair, Inc. J. Douglas Way, Jason Porter, Neil Patki, and Madison Kelley Colorado School of Mines Josh Stanislowski and Scott Tolbert University of North Dakota - Energy and Environmental Research Center December 23, 2015 PREPARED FOR THE UNITED STATES DEPARTMENT OF ENERGY Under

  16. Regional Transportation Simulation Tool for Emergency Planning

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

    rtstep-diag TRACC RESEARCH Computational Fluid Dynamics Computational Structural Mechanics Transportation Systems Modeling Regional Transportation Simulation Tool for Emergency Evacuation Planning (Click to play movie) Large-scale evacuations from major cities during no-notice events - such as chemical or radiological attacks, hazardous material spills, or earthquakes - have an obvious impact on large regions rather than on just the directly affected area. The scope of impact includes the

  17. Research Highlight

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

    Submitter: Area of Research: Journal Reference: N/A

  18. Characterization of the nanoDot OSLD dosimeter in CT

    SciTech Connect (OSTI)

    Scarboro, Sarah B.; Cody, Dianna; Followill, David; Court, Laurence; Stingo, Francesco C.; Kry, Stephen F.; Alvarez, Paola; Zhang, Di; McNitt-Gray, Michael

    2015-04-15

    Purpose: The extensive use of computed tomography (CT) in diagnostic procedures is accompanied by a growing need for more accurate and patient-specific dosimetry techniques. Optically stimulated luminescent dosimeters (OSLDs) offer a potential solution for patient-specific CT point-based surface dosimetry by measuring air kerma. The purpose of this work was to characterize the OSLD nanoDot for CT dosimetry, quantifying necessary correction factors, and evaluating the uncertainty of these factors. Methods: A characterization of the Landauer OSL nanoDot (Landauer, Inc., Greenwood, IL) was conducted using both measurements and theoretical approaches in a CT environment. The effects of signal depletion, signal fading, dose linearity, and angular dependence were characterized through direct measurement for CT energies (80140 kV) and delivered doses ranging from ?5 to >1000 mGy. Energy dependence as a function of scan parameters was evaluated using two independent approaches: direct measurement and a theoretical approach based on Burlin cavity theory and Monte Carlo simulated spectra. This beam-quality dependence was evaluated for a range of CT scanning parameters. Results: Correction factors for the dosimeter response in terms of signal fading, dose linearity, and angular dependence were found to be small for most measurement conditions (<3%). The relative uncertainty was determined for each factor and reported at the two-sigma level. Differences in irradiation geometry (rotational versus static) resulted in a difference in dosimeter signal of 3% on average. Beam quality varied with scan parameters and necessitated the largest correction factor, ranging from 0.80 to 1.15 relative to a calibration performed in air using a 120 kV beam. Good agreement was found between the theoretical and measurement approaches. Conclusions: Correction factors for the measurement of air kerma were generally small for CT dosimetry, although angular effects, and particularly effects due to changes in beam quality, could be more substantial. In particular, it would likely be necessary to account for variations in CT scan parameters and measurement location when performing CT dosimetry using OSLD.

  19. Cavity-enhanced single photon emission from site-controlled In(Ga)As quantum dots fabricated using nanoimprint lithography

    SciTech Connect (OSTI)

    Tommila, J.; Hakkarainen, T. V.; Schramm, A. Guina, M.; Belykh, V. V.; Sibeldin, N. N.; Heinonen, E.

    2014-05-26

    We report on the emission dynamics of single In(Ga)As quantum dots formed in etched GaAs pits and integrated into micropillar cavities. The site-controlled quantum dots were fabricated by molecular beam epitaxy on nanoimprint lithography patterned GaAs(001) surfaces. Triggered single photon emission confirmed by photon autocorrelation measurements is demonstrated. Time-resolved photoluminescence experiments clearly show an effect of the cavity on the spontaneous emission rate of the quantum dot.

  20. Ground state energy of an exciton in a spherical quantum dot in the presence of an external magnetic field

    SciTech Connect (OSTI)

    Jahan K, Luhluh Boda, Aalu; Chatterjee, Ashok

    2015-05-15

    The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the presence of an external magnetic field. A variational method is employed to obtain the ground state energy of the exciton as a function of the quantum dot size, the confinement strength and the magnetic field. It is also shown that the variation of the size of the exciton with the radius of the quantum dot.

  1. Electrically driven single photon emission from a CdSe/ZnSSe single quantum dot at 200?K

    SciTech Connect (OSTI)

    Quitsch, Wolf; Kmmell, Tilmar; Bacher, Gerd; Gust, Arne; Kruse, Carsten; Hommel, Detlef

    2014-09-01

    High temperature operation of an electrically driven single photon emitter based on a single epitaxial quantum dot is reported. CdSe/ZnSSe/MgS quantum dots are embedded into a p-i-n diode architecture providing almost background free excitonic and biexcitonic electroluminescence from individual quantum dots through apertures in the top contacts. Clear antibunching with g{sup 2}(??=?0)?=?0.28??0.20 can be tracked up to T?=?200?K, representing the highest temperature for electrically triggered single photon emission from a single quantum dot device.

  2. Alternative Transportation Technologies: Hydrogen, Biofuels,...

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

    Transportation Technologies: Hydrogen, Biofuels, Advanced Efficiency, and Plug-in Hybrid Electric Vehicles Alternative Transportation Technologies: Hydrogen, Biofuels, Advanced ...

  3. Quantum-Dots Based Electrochemical Immunoassay of Interleukin-1?

    SciTech Connect (OSTI)

    Wu, Hong; Liu, Guodong; Wang, Jun; Lin, Yuehe

    2007-07-01

    We describe a quantum-dot (QD, CdSe@ZnS)-based electrochemical immunoassay to detect a protein biomarker, interleukin-1? (IL-1?). QD conjugated with anti-IL-1? antibody was used as a label in an immunorecognition event. After a complete sandwich immunoreaction among the primary IL-1? antibody (immobilized on the avidin-modified magnetic beads), IL-1?, and the QD-labeled secondary antibody, QD labels were attached to the magnetic-bead surface through the antibody-antigen immunocomplex. Electrochemical stripping analysis of the captured QDs was used to quantify the concentration of IL-1? after an acid-dissolution step. The streptavidin-modified magnetic beads and the magnetic separation platform were used to integrate a facile antibody immobilization (through a biotin/streptavidin interaction) with immunoreactions and the isolation of immunocomplexes from reaction solutions in the assay. The voltammetric response is highly linear over the range of 0.5 to 50 ng mL-1 IL 1?, and the limit of detection is estimated to be 0.3 ng mL-1 (18 pM). This QD-based electrochemical immunoassay shows great promise for rapid, simple, and cost-effective analysis of protein biomarkers.

  4. Quantum Dot Solar Cells: High Efficiency through Multiple Exciton Generation

    SciTech Connect (OSTI)

    Hanna, M. C.; Ellingson, R. J.; Beard, M.; Yu, P.; Micic, O. I.; Nozik, A. J.; c.

    2005-01-01

    Impact ionization is a process in which absorbed photons in semiconductors that are at least twice the bandgap can produce multiple electron-hole pairs. For single-bandgap photovoltaic devices, this effect produces greatly enhanced theoretical thermodynamic conversion efficiencies that range from 45-85%, depending upon solar concentration, the cell temperature, and the number of electron-hole pairs produced per photon. For quantum dots (QDs), electron-hole pairs exist as excitons. We have observed astoundingly efficient multiple exciton generation (MEG) in QDs of PbSe (bulk Eg = 0.28 eV), ranging in diameter from 3.9 to 5.7nm (Eg = 0.73, 0.82, and 0.91 eV, respectively). The effective masses of electron and holes are about equal in PbSe, and the onset for efficient MEG occurs at about three times the QD HOMO-LUMO transition (its ''bandgap''). The quantum yield rises quickly after the onset and reaches 300% at 4 x Eg (3.64 eV) for the smallest QD; this means that every QD in the sample produces three electron-hole pairs/photon.

  5. PROPERTIES OF UMBRAL DOTS FROM STRAY LIGHT CORRECTED HINODE FILTERGRAMS

    SciTech Connect (OSTI)

    Louis, Rohan E.; Mathew, Shibu K.; Bayanna, A. Raja; Rubio, Luis R. Bellot; Ichimoto, Kiyoshi; Ravindra, B.

    2012-06-20

    High-resolution blue continuum filtergrams from Hinode are employed to study the umbral fine structure of a regular unipolar sunspot. The removal of scattered light from the images increases the rms contrast by a factor of 1.45 on average. Improvement in image contrast renders identification of short filamentary structures resembling penumbrae that are well separated from the umbra-penumbra boundary and comprise bright filaments/grains flanking dark filaments. Such fine structures were recently detected from ground-based telescopes and have now been observed with Hinode. A multi-level tracking algorithm was used to identify umbral dots (UDs) in both the uncorrected and corrected images and to track them in time. The distribution of the values describing the photometric and geometric properties of UDs is more easily affected by the presence of stray light while it is less severe in the case of kinematic properties. Statistically, UDs exhibit a peak intensity, effective diameter, lifetime, horizontal speed, and a trajectory length of 0.29I{sub QS}, 272 km, 8.4 minutes, 0.45 km s{sup -1}, and 221 km, respectively. The 2 hr 20 minute time sequence depicts several locations where UDs tend to appear and disappear repeatedly with various time intervals. The correction for scattered light in the Hinode filtergrams facilitates photometry of umbral fine structure, which can be related to results obtained from larger telescopes and numerical simulations.

  6. High color rendering index white light emitting diodes fabricated from a combination of carbon dots and zinc copper indium sulfide quantum dots

    SciTech Connect (OSTI)

    Sun, Chun; Liu, Wenyan; Zhang, Xiaoyu; Zhang, Yu E-mail: wyu6000@gmail.com; Wang, Yu; Kalytchuk, Sergii; Kershaw, Stephen V.; Rogach, Andrey L.; Zhang, Tieqiang; Zhao, Jun; Yu, William W. E-mail: wyu6000@gmail.com

    2014-06-30

    In a line with most recent trends in developing non-toxic fluorescent nanomaterials, we combined blue emissive carbon dots with green and red emissive zinc copper indium sulfide (ZCIS) core/shell quantum dots (QDs) to achieve white light-emitting diodes (WLEDs) with a high color rendering index of 93. This indicates that ZCIS QDs, with their broad emission bands, can be employed to effectively make up the emission of carbon dots in the yellow and red regions to produce WLEDs in the wide region of color temperature by tuning the volume ratio of these constituting luminophores. Their electroluminescence characteristics including color rendering index, Commission Internationale de l'Eclairage (CIE) color coordinates, and color temperatures were evaluated as a function of forward current. The CIE-1931 chromaticity coordinates of the as-prepared WLEDs, exhibiting good stability, were slightly shifted from (0.321, 0.312) at 10?mA to (0.351, 0.322) at 30?mA, which was mainly caused by the different thermal quenching coefficients of carbon dots and ZCIS QDs.

  7. Future of Transportation

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

    Transportation In the coming decades, transportation in the U.S. is expected to change radically in response to environmental constraints, fluctuating oil availability and economic factors. Future Decision-Makers The transportation systems that emerge in the 21 st century will be defined largely by the choices, skills and imaginations of today's youth. Future Workforce As scientists and engineers, they will develop new vehicle and fuel technologies. As citizens, they will make decisions

  8. Intelligent Transportation Systems

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

    Intelligent Transportation Systems This email address is being protected from spambots. You need JavaScript enabled to view it. - TRACC Director Background The development and deployment of Intelligent Transportation Systems (ITS) in the United States is an effort of national importance. Through the use of advanced computing, control, and communication technologies, ITS promises to greatly improve the efficiency and safety of the existing surface transportation system and reduce the

  9. National Transportation Stakeholders Forum

    Office of Environmental Management (EM)

    N ti l T t ti National Transportation Stakeholders Forum Chicago, IL, May 26, 2010 Ahmad Al-Daouk Date and page number - 1 Director, National Security Department National Nuclear Security Administration Service Center - Albuquerque, NM National Transportation Stakeholders Forum OSRP * NNSA Contractors transporting in commerce, are required law to comply with applicable regulations required law to comply with applicable regulations (e.g. federal, local, tribal) * Great majority of NNSA shipments

  10. Radioactive Material Transportation Practices

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2002-09-23

    Establishes standard transportation practices for Departmental programs to use in planning and executing offsite shipments of radioactive materials including radioactive waste. Does not cancel other directives.

  11. Sustainable Transportation (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-09-01

    This document highlights DOE's Office of Energy Efficiency and Renewable Energy's advancements in transportation technologies, alternative fuels, and fuel cell technologies.

  12. UZ Colloid Transport Model

    SciTech Connect (OSTI)

    M. McGraw

    2000-04-13

    The UZ Colloid Transport model development plan states that the objective of this Analysis/Model Report (AMR) is to document the development of a model for simulating unsaturated colloid transport. This objective includes the following: (1) use of a process level model to evaluate the potential mechanisms for colloid transport at Yucca Mountain; (2) Provide ranges of parameters for significant colloid transport processes to Performance Assessment (PA) for the unsaturated zone (UZ); (3) Provide a basis for development of an abstracted model for use in PA calculations.

  13. Transportation Energy Futures Snapshot

    Broader source: Energy.gov [DOE]

    This snapshot is a summary of the EERE reports that provide a detailed analysis of opportunities and challenges along the path to a more sustainable transportation energy future.

  14. Transportation Energy Futures Snapshot

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

    modes, manage the demand for transportation, and shift the fuel mix to more sustainable sources necessary to reach these significant outcomes. Coordinating a...

  15. Natural Gas Transportation Resiliency

    Broader source: Energy.gov (indexed) [DOE]

    Transportation Resiliency Anders Johnson Director Pipeline System Design April 29, 2014 Confidential and Illustrative for discussion purposes only. The views expressed in this...

  16. WASTE PACKAGE TRANSPORTER DESIGN

    SciTech Connect (OSTI)

    D.C. Weddle; R. Novotny; J. Cron

    1998-09-23

    The purpose of this Design Analysis is to develop preliminary design of the waste package transporter used for waste package (WP) transport and related functions in the subsurface repository. This analysis refines the conceptual design that was started in Phase I of the Viability Assessment. This analysis supports the development of a reliable emplacement concept and a retrieval concept for license application design. The scope of this analysis includes the following activities: (1) Assess features of the transporter design and evaluate alternative design solutions for mechanical components. (2) Develop mechanical equipment details for the transporter. (3) Prepare a preliminary structural evaluation for the transporter. (4) Identify and recommend the equipment design for waste package transport and related functions. (5) Investigate transport equipment interface tolerances. This analysis supports the development of the waste package transporter for the transport, emplacement, and retrieval of packaged radioactive waste forms in the subsurface repository. Once the waste containers are closed and accepted, the packaged radioactive waste forms are termed waste packages (WP). This terminology was finalized as this analysis neared completion; therefore, the term disposal container is used in several references (i.e., the System Description Document (SDD)) (Ref. 5.6). In this analysis and the applicable reference documents, the term ''disposal container'' is synonymous with ''waste package''.

  17. Photonics Research and Development

    SciTech Connect (OSTI)

    Pookpanratana, Sujitra; Shlayan, Neveen; Venkat, Rama; Das, Bisjwajit; Boehm, Bob; Heske, Clemens; Fraser, Donald; Moustakas, Theodore

    2010-01-15

    During the period August 2005 through October 2009, the UNLV Research Foundation (UNLVRF), a non-profit affiliate of the University of Nevada, Las Vegas (UNLV), in collaboration with UNLV??s Colleges of Science and Engineering; Boston University (BU); Oak Ridge National Laboratory (ORNL); and Sunlight Direct, LLC, has managed and conducted a diverse and comprehensive research and development program focused on light-emitting diode (LED) technologies that provide significantly improved characteristics for lighting and display applications. This final technical report provides detailed information on the nature of the tasks, the results of the research, and the deliverables. It is estimated that about five percent of the energy used in the nation is for lighting homes, buildings and streets, accounting for some 25 percent of the average home??s electric bill. However, the figure is significantly higher for the commercial sector. About 60 percent of the electricity for businesses is for lighting. Thus replacement of current lighting with solid-state lighting technology has the potential to significantly reduce this nation??s energy consumption ?? by some estimates, possibly as high as 20%. The primary objective of this multi-year R&D project has been to develop and advance lighting technologies to improve national energy conversion efficiencies; reduce heat load; and significantly lower the cost of conventional lighting technologies. The UNLVRF and its partners have specifically focused these talents on (1) improving LED technologies; (2) optimizing hybrid solar lighting, a technology which potentially offers the benefits of blending natural with artificial lighting systems, thus improving energy efficiency; and (3) building a comprehensive academic infrastructure within UNLV which concentrates on photonics R&D. Task researchers have reported impressive progress in (1) the development of quantum dot laser emitting diodes (QDLEDs) which will ultimately improve energy efficiency and lower costs for display and lighting applications (UNLV College of Engineering); (2) advancing green LED technology based on the Indium-Gallium-Nitride system (BU), thus improving conversion efficiencies; (3) employing unique state-of-the-art X-ray, electron and optical spectroscopies with microscopic techniques to learn more about the electronic structure of materials and contacts in LED devices (UNLV College of Science); (4) establishing a UNLV Display Lighting Laboratory staffed with a specialized team of academic researchers, students and industrial partners focused on identifying and implementing engineering solutions for lighting display-related problems; and (5) conducting research, development and demonstration for HSL essential to the resolution of technological barriers to commercialization.

  18. About GE Global Research Center | GE Global Research

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

    About GE Global Research GE has come a long way since the first bulb gave light. Find out what we're doing now, meet our leaders or contact us with questions. Home > About GE Global Research What We Do Making aircraft engines more efficient. Powering the world with flexible gas turbines. Crunching big data. Pioneering the Industrial Internet. Creating greener ground transportation. Refining medical imaging for the future. GE Global Research has served as the cornerstone of GE innovation for

  19. Semiconductor Quantum Dots and Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells

    SciTech Connect (OSTI)

    Nozik, Arthur J.; Beard, Matthew C.; Luther, Joseph M.; Law, Matt; Ellingson, Randy J.; Johnson, Justin C.

    2010-10-14

    Here, we will first briefly summarize the general principles of QD synthesis using our previous work on InP as an example. Then we will focus on QDs of the IV-VI Pb chalcogenides (PbSe, PbS, and PbTe) and Si QDs because these were among the first QDs that were reported to produce multiple excitons upon absorbing single photons of appropriate energy (a process we call multiple exciton generation (MEG)). We note that in addition to Si and the Pb-VI QDs, two other semiconductor systems (III-V InP QDs(56) and II-VI core-shell CdTe/CdSe QDs(57)) were very recently reported to also produce MEG. Then we will discuss photogenerated carrier dynamics in QDs, including the issues and controversies related to the cooling of hot carriers and the magnitude and significance of MEG in QDs. Finally, we will discuss applications of QDs and QD arrays in novel quantum dot PV cells, where multiple exciton generation from single photons could yield significantly higher PV conversion efficiencies.

  20. Multi-stacked InAs/GaAs quantum dots grown with different growth modes for quantum dot solar cells

    SciTech Connect (OSTI)

    Kim, Yeongho; Ban, Keun-Yong Honsberg, Christiana B.

    2015-06-01

    We have studied the material properties and device performance of InAs/GaAs quantum dot solar cells (QDSCs) made using three different QD growth modes: Stranski-Krastanov (S-K), quasi-monolayer (QML), and sub-monolayer (SML) growth modes. All QDSCs show an extended external quantum efficiency (EQE) at near infrared wavelengths of 9501070?nm from the QD absorption. Compared to the S-K and SML QDSCs, the QML QDSC with a higher strain exhibits a poor EQE response in the wavelength region of 300880?nm due to increased non-radiative recombination. The conversion efficiency of the S-K and SML QDSCs exceeds that of the reference cell (13.4%) without QDs due to an enhanced photocurrent (>16% increase) produced by the silicon doped QD stacks. However, as expected from the EQE of the QML QDSC, the increase of strain-induced crystalline defects greatly degrades the photocurrent and open-circuit voltage, leading to the lowest conversion efficiency (8.9%)

  1. Research Highlight

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

    that extreme stand-off distance, there is no access to spatial information, i.e., no estimation of the horizontal transport from laser beam to point of escape from cloud boundary....

  2. Photoluminescence properties of cadmium-selenide quantum dots embedded in a liquid-crystal polymer matrix

    SciTech Connect (OSTI)

    Tselikov, G. I. Timoshenko, V. Yu.; Plenge, J.; Ruehl, E.; Shatalova, A. M.; Shandryuk, G. A.; Merekalov, A. S.; Tal'roze, R. V.

    2013-05-15

    The photoluminescence properties of cadmium-selenide (CdSe) quantum dots with an average size of {approx}3 nm, embedded in a liquid-crystal polymer matrix are studied. It was found that an increase in the quantum-dot concentration results in modification of the intrinsic (exciton) photoluminescence spectrum in the range 500-600 nm and a nonmonotonic change in its intensity. Time-resolved measurements show the biexponential decay of the photoluminescence intensity with various ratios of fast and slow components depending on the quantum-dot concentration. In this case, the characteristic lifetimes of exciton photoluminescence are 5-10 and 35-50 ns for the fast and slow components, respectively, which is much shorter than the times for colloidal CdSe quantum dots of the same size. The observed features of the photoluminescence spectra and kinetics are explained by the effects of light reabsorption, energy transfer from quantum dots to the liquid-crystal polymer matrix, and the effect of the electronic states at the CdSe/(liquid crystal) interface.

  3. Inhibition of plasmonically enhanced interdot energy transfer in quantum dot solids via photo-oxidation

    SciTech Connect (OSTI)

    Sadeghi, S. M.; Nejat, A.; West, R. G.

    2012-11-15

    We studied the impact of photophysical and photochemical processes on the interdot Forster energy transfer in monodisperse CdSe/ZnS quantum dot solids. For this, we investigated emission spectra of CdSe/ZnS quantum dot solids in the vicinity of gold metallic nanoparticles coated with chromium oxide. The metallic nanoparticles were used to enhance the rate of the energy transfer between the quantum dots, while the chromium oxide coating led to significant increase of their photo-oxidation rates. Our results showed that irradiation of such solids with a laser beam can lead to unique spectral changes, including narrowing and blue shift. We investigate these effects in terms of inhibition of the plasmonically enhanced interdot energy transfer between quantum dots via the chromium-oxide accelerated photo-oxidation process. We demonstrate this considering energy-dependent rate of the interdot energy transfer process, plasmonic effects, and the way photo-oxidation enhances non-radiative decay rates of quantum dots with different sizes.

  4. Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes

    SciTech Connect (OSTI)

    Verma, Jai; Kandaswamy, Prem Kumar; Protasenko, Vladimir; Verma, Amit; Grace Xing, Huili; Jena, Debdeep

    2013-01-28

    We demonstrate a GaN quantum dot ultraviolet light-emitting diode that uses tunnel injection of carriers through AlN barriers into the active region. The quantum dot heterostructure is grown by molecular beam epitaxy on AlN templates. The large lattice mismatch between GaN and AlN favors the formation of GaN quantum dots in the Stranski-Krastanov growth mode. Carrier injection by tunneling can mitigate losses incurred in hot-carrier injection in light emitting heterostructures. To achieve tunnel injection, relatively low composition AlGaN is used for n- and p-type layers to simultaneously take advantage of effective band alignment and efficient doping. The small height of the quantum dots results in short-wavelength emission and are simultaneously an effective tool to fight the reduction of oscillator strength from quantum-confined Stark effect due to polarization fields. The strong quantum confinement results in room-temperature electroluminescence peaks at 261 and 340 nm, well above the 365 nm bandgap of bulk GaN. The demonstration opens the doorway to exploit many varied features of quantum dot physics to realize high-efficiency short-wavelength light sources.

  5. Harmonization - Two Years' of Transportation Regulation Lessons Learned

    SciTech Connect (OSTI)

    Colborn, K.

    2007-07-01

    The U.S. Department of Transportation issued modifications to the Hazardous Materials Regulations in October, 2004 as part of an ongoing effort to 'harmonize' U.S. regulations with those of the International Atomic Energy Agency. The harmonization effort had several predictable effects on low level radioactive materials shipment that were anticipated even prior to their implementation. However, after two years' experience with the new regulations, transporters have identified several effects on transportation which were not entirely apparent when the regulations were first implemented. This paper presents several case studies in the transportation of low level radioactive materials since the harmonization rules took effect. In each case, an analysis of the challenge posed by the regulatory revision is provided. In some cases, more than one strategy for compliance was considered, and the advantages and disadvantages of each are discussed. In several cases, regulatory interpretations were sought and obtained, and these are presented to clarify the legitimacy of the compliance approach. The presentation of interpretations will be accompanied by reports of clarifying discussions with the U.S. DOT about the interpretation and scope of the regulatory change. Specific transportation issues raised by the revised hazardous materials regulations are reviewed, including: The new definition of radioactive material in accordance with isotope-specific concentration and total activity limits. The new hazardous materials regulations (HMR) created a new definition for radioactive material. A case study is presented for soils contaminated with low levels of Th-230. These soils had been being shipped for years as exempt material under the old 2,000 pCi/g concentration limit. Under the new HMR, these same soils were radioactive material. Further, in rail-car quantities their activity exceeded an A2 value, so shipment of the material in gondolas appeared to require an IP-2 package. Interpretations, discussions, and an exemption were obtained to secure the continued shipment of this material. A provision to allow 'natural' radioactive materials to be exempt from the requirements of the HMR at up to 10x the listed isotopic concentrations. The revised HMR exempts certain natural materials and ores from regulation as radioactive material at concentrations up to 10x that allowed if the materials are not natural. The term 'natural' is not well defined, and initial attempts to qualify for this exemption were thwarted by concerns over what degree of material processing, if any, materials could experience and still be considered 'natural'. The presentation includes an example from a project involving post-processed tungsten ore, and includes interpretations from the US DOT as well as clarifying language from current and drafted IAEA regulation and guidance. New packaging descriptions allowing the use of cargo containers as IP-2 and IP-3 packages in some applications. The revised HMR provides an alternate certification procedure under which standard cargo containers can be used as IP-2 and IP-3 containers. There has been some confusion about how this high level of certification can apply to standard cargo containers when other sections of the regulations make this certification available only to considerably more stout containers after rigorous testing. The discussion includes interpretive guidance from the US DOT, and from the UK Department of Transport clarifying the same provision in IAEA regulations. A new definition of contamination with apparently broad impact on the shipment of empty containers and conveyances. The revised HMR presented a definition of contamination not referenced by any other part of the HMR. The preamble to the revised HMR provides confusing guidance on the application of the definition to shipment of empty containers, and subsequent interpretive guidance letters appear to conflict with the preamble as well as with each other. The definition also has the effect of regulating materials for transport as radioactive even when US

  6. Research Gallery

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

    Research Gallery Research Gallery Exhibits in this gallery capture Laboratory's leading-edge research in many areas of science and technology to help solve national problems related to energy, the environment, infrastructure, and health. August 18, 2014 Museum floor plan showing the Research Gallery Basic research conducted here enhances our national defense and global security missions. Science serving society The Laboratory conducts leading-edge research in many areas of science and technology

  7. Research Highlights

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

    Highlights Form Submit a New Research Highlight Sort Highlights Submitter Title Research Area Working Group Submission Date DOE Progress Reports Notable Research Findings for 2001-2006 Office of Science Abstracts Database Research Highlights Summaries Research Highlights Members of ARM's science team are major contributors to radiation and cloud research. ARM investigators publish about 150 refereed journal articles per year, and ARM data are used in many studies published by other scientific

  8. HYDROGEN COMMERCIALIZATION: TRANSPORTATION FUEL FOR THE 21ST CENTURY

    SciTech Connect (OSTI)

    APOLONIO DEL TORO

    2008-05-27

    Since 1999, SunLine Transit Agency has worked with the U.S. Department of Energy (DOE), U.S. Department of Defense (DOD), and the U.S. Department of Transportation (DOT) to develop and test hydrogen infrastructure, fuel cell buses, a heavy-duty fuel cell truck, a fuel cell neighborhood electric vehicle, fuel cell golf carts and internal combustion engine buses operating on a mixture of hydrogen and compressed natural gas (CNG). SunLine has cultivated a rich history of testing and demonstrating equipment for leading industry manufacturers in a pre-commercial environment. Visitors to SunLine's "Clean Fuels Mall" from around the world have included government delegations and agencies, international journalists and media, industry leaders and experts and environmental and educational groups.

  9. Research Highlight

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

    to Terrestrial Radiation Download a printable PDF Submitter: Mitchell, D. L., Desert Research Institute Area of Research: General Circulation and Single Column Models...

  10. Research Projects

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

    Current Research Projects Joint Los Alamos National LaboratoryUCSD Research Projects Collaborations between Los Alamos National Laboratory and the University of California at San...

  11. Research Highlight

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

    Chinese Researchers Report Reliable Method for Monitoring Soil Moisture Submitter: Bhattacharya, A., Pacific Northwest National Laboratory Area of Research: Surface Properties...

  12. Research Highlight

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

    Testing and Comparing the Modified Anomalous Diffraction Approximation Submitter: Mitchell, D. L., Desert Research Institute Area of Research: Cloud DistributionsCharacterizations...

  13. Research Highlight

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

    ARM Program Research Improves Longwave Radiative Transfer Models Submitter: Turner, D. D., National Oceanic and Atmospheric Administration Area of Research: General Circulation and...

  14. Research Highlight

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

    Fog and Rain in the Amazon For original submission and image(s), see ARM Research Highlights http:www.arm.govsciencehighlights Research Highlight The diurnal and seasonal...

  15. Research Highlight

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

    Research Masters the Misunderstood Mixed-Phase Cloud Download a printable PDF Submitter: Ovchinnikov, M., Pacific Northwest National Laboratory Area of Research:...

  16. Transport Version 3

    Energy Science and Technology Software Center (OSTI)

    2008-05-16

    The Transport version 3 (T3) system uses the Network News Transfer Protocol (NNTP) to move data from sources to a Data Reporisoty (DR). Interested recipients subscribe to newsgroups to retrieve data. Data in transport is protected by AES-256 and RSA cryptographic services provided by the external OpenSSL cryptographic libraries.

  17. Packaging and Transportation Safety

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2003-04-04

    To establish safety requirements for the proper packaging and transportation of Department of Energy (DOE)/National Nuclear Security Administration (NNSA) offsite shipments and onsite transfers of hazardous materials and for modal transport. Cancels DOE O 460.1A. Canceled by DOE O 460.1C.

  18. Consent Versus Consensus - Stakehold Involvement in the Identification of Necessary and Sufficient Transportation

    SciTech Connect (OSTI)

    Fawcett, Ricky Lee; Kramer, George Leroy Jr.

    2003-03-01

    Transportation (DOT) and the Nuclear Regulatory Commission (NRC) to provide for the protection of the public and the environment; historically these regulations have proven quite sufficient. Even so, when the Department of Energy (DOE) makes radioactive materials shipments, that are deemed to be a major federal activity, regulations under the National Environmental Policy Act require that public input on safety issues be sought. This requirement leads to interactions with State, Tribal and local stakeholders that often result in the imposition of extra-regulatory requirements requirements beyond those prescribed by DOT and NRC regulations. Unfortunately, these additional requirements virtually always increase costs and delay schedules, and usually do so without significantly increasing, and possibly even decreasing overall transportation safety. We believe that this problem arises because of efforts to achieve stakeholder consensus rather than stakeholder consent, where consensus connotes universal agreement with all aspects of the program, while consent, as used here, is simple agreement with the overall course of action. Gaining consensus entails extensive negotiations because all aspects and requirements of the project must be agreed to by each stakeholder. Gaining consent, on the other hand, requires only that stakeholders be satisfied that the project, as planned, provides adequately for their safety needs. This article addresses the issue of consent versus consensus and proposes a systematic, decision science process for reaching consent. Key steps in this proposed process are early identification and involvement of stakeholders, compilation of their concerns, perceptions, needs, causes, and translation of that information into an appropriate set of derived requirements. These derived requirements, along with already-established DOT and NRC regulatory requirements, form the necessary and sufficient conditions for safe transportation and for obtaining stakeholder consent.

  19. Radioactive Material Transportation Considerations with Respect to DOE 3013 Storage Containers

    SciTech Connect (OSTI)

    HENSEL, SJ

    2004-04-15

    This paper evaluates sealed hardware that meets the requirements of DOE-STD-3013, ''Criteria for Preparing and packaging Plutonium Metals and Oxides for Long-Term Storage'' with respect to radioactive material (Type B quantity) transportation requirements. The Standard provides criteria for packaging of the plutonium materials for storage periods of at least 50 years. The standard requires the hardware to maintain integrity under both normal storage conditions and under anticipated handling conditions. To accomplish this, the standard requires that the plutonium be loaded in a minimum of two nested stainless steel sealed containers that are both tested for leak-tightness per ANSI N14.5. As such the 3013 hardware is robust. While the 3013 STD may provide appropriate storage criteria, it is not intended to provide criteria for transporting the material under the requirements of the Department of Transportation (DOT). In this evaluation, it is assumed that the activity of plutonium exceeds A1 and/or A2 curies as defined in DOT 49 CFR 173.431 and therefore must be shipped as a Type B package meeting the Nuclear Regulatory Commission (NRC) requirements of 10 CFR 71. The evaluation considers Type B shipment of plutonium in the 3013 hardware within a certified package for such contents.

  20. Microscopic model for intersubband gain from electrically pumped quantum-dot structures

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

    Michael, Stephan; Chow, Weng Wah; Schneider, Han Christian

    2014-10-03

    We study theoretically the performance of electrically pumped self-organized quantum dots as a gain material in the mid-infrared range at room temperature. We analyze an AlGaAs/InGaAs based structure composed of dots-in-a-well sandwiched between two quantum wells. We numerically analyze a comprehensive model by combining a many-particle approach for electronic dynamics with a realistic modeling of the electronic states in the whole structure. We investigate the gain both for quasi-equilibrium conditions and current injection. We find, comparing different structures, that steady-state gain can only be realized by an efficient extraction process, which prevents an accumulation of electrons in continuum states, thatmore » make the available scattering pathways through the quantum-dot active region too fast to sustain inversion.« less

  1. Extraction of inhomogeneous broadening and nonradiative losses in InAs quantum-dot lasers

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

    Chow, Weng W.; Liu, Alan Y.; Gossard, Arthur C.; Bowers, John E.

    2015-10-28

    We present a method to quantify inhomogeneous broadening and nonradiative losses in quantum dot lasers by comparing the gain and spontaneous emission results of a microscopic laser theory with measurements made on 1.3 μm InAs quantum-dot lasers. Calculated spontaneous-emission spectra are first matched to those measured experimentally to determine the inhomogeneous broadening in the experimental samples. This is possible because treatment of carrier scattering at the level of quantum kinetic equations provides the homogeneously broadened spectra without use of free parameters, such as the dephasing rate. Thus we then extract the nonradiative recombination current associated with the quantum-dot active regionmore » from a comparison of measured and calculated gain versus current relations.« less

  2. Enhanced spontaneous emission of CdSe quantum dots in monolithic II-VI pillar microcavities

    SciTech Connect (OSTI)

    Lohmeyer, H.; Kruse, C.; Sebald, K.; Gutowski, J.; Hommel, D.

    2006-08-28

    The emission properties of CdSe/ZnSe quantum dots in ZnSe-based pillar microcavities are studied. All-epitaxial cavities made of ZnSSe and MgS/ZnCdSe superlattices with a single quantum-dot sheet embedded have been grown by molecular beam epitaxy. Pillar structures with diameters down to 500 nm have been realized by focused-ion-beam etching. A pronounced enhancement of the spontaneous emission rate of quantum dots coupling to the fundamental mode of the cavities is found as evidence for the Purcell effect. The enhancement by a factor of up to 3.8 depends systematically on the pillar diameter and thus on the Purcell factor of the individual pillars.

  3. Luminescence of CdSe/ZnS quantum dots infiltrated into an opal matrix

    SciTech Connect (OSTI)

    Gruzintsev, A. N. Emelchenko, G. A.; Masalov, V. M.; Yakimov, E. E.; Barthou, C.; Maitre, A.

    2009-02-15

    The effect of the photonic band gap in the photonic crystal, the synthesized SiO{sub 2} opal with embedded CdSe/ZnS quantum dots, on its luminescence in the visible spectral region is studied. It is shown that the position of the photonic band gap in the luminescence and reflectance spectra for the infiltrated opal depends on the diameter of the constituent nanospheres and on the angle of recording the signal. The optimal conditions for embedding the CdSe/ZnS quantum dots from the solution into the opal matrix are determined. It is found that, for the opal-CdSe/ZnS nanocomposites, the emission intensity decreases and the luminescence decay time increases in the spatial directions, in which the spectral positions of the photonic band gap and the luminescence peak of the quantum dots coincide.

  4. Design of quantum dot lattices in amorphous matrices by ion beam irradiation

    SciTech Connect (OSTI)

    Buljan, M.; Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Jaksic, M.; Salamon, K.; Drazic, G.; Bernstorff, S.; Holy, V.

    2011-10-15

    We report on the highly controllable self-assembly of semiconductor quantum dots and metallic nanoparticles in a solid amorphous matrix, induced by ion beam irradiation of an amorphous multilayer. We demonstrate experimentally and theoretically a possibility to tune the basic structural properties of the quantum dots in a wide range. Furthermore, the sizes, distances, and arrangement type of the quantum dots follow simple equations dependent on the irradiation and the multilayer properties. We present a Monte Carlo model for the simulation and prediction of the structural properties of the materials formed by this method. The presented results enable engineering and simple production of functional materials or simple devices interesting for applications in nanotechnology.

  5. Probing the dependence of electron transfer on size and coverage in carbon nanotube-quantum dot heterostructures

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

    Wang, Lei; Wong, Stanislaus S.; Han, Jinkyu; Zhu, Yuqi; Jaye, Cherno; Liu, Haiqing; Li, Zhuo -Qun; Taylor, Gordon T.; Fischer, Daniel A.; Appenzeller, Joerg; et al

    2015-11-16

    As a model system for understanding charge transfer in novel architectural designs for solar cells, double-walled carbon nanotube (DWNT)–CdSe quantum dot (QD) (QDs with average diameters of 2.3, 3.0, and 4.1 nm) heterostructures have been fabricated. The individual nanoscale building blocks were successfully attached and combined using a hole-trapping thiol linker molecule, i.e., 4-mercaptophenol (MTH), through a facile, noncovalent π–π stacking attachment strategy. Transmission electron microscopy confirmed the attachment of QDs onto the external surfaces of the DWNTs. We herein demonstrate a meaningful and unique combination of near-edge X-ray absorption fine structure (NEXAFS) and Raman spectroscopies bolstered by complementary electricalmore » transport measurements in order to elucidate the synergistic interactions between CdSe QDs and DWNTs, which are facilitated by the bridging MTH molecules that can scavenge photoinduced holes and potentially mediate electron redistribution between the conduction bands in CdSe QDs and the C 2p-derived states of the DWNTs. Specifically, we correlated evidence of charge transfer as manifested by (i) changes in the NEXAFS intensities of π* resonance in the C K-edge and Cd M3-edge spectra, (ii) a perceptible outer tube G-band downshift in frequency in Raman spectra, as well as (iii) alterations in the threshold characteristics present in transport data as a function of CdSe QD deposition onto the DWNT surface. Furthermore, the separate effects of (i) varying QD sizes and (ii) QD coverage densities on the electron transfer were independently studied.« less

  6. Probing the dependence of electron transfer on size and coverage in carbon nanotube-quantum dot heterostructures

    SciTech Connect (OSTI)

    Wang, Lei; Wong, Stanislaus S.; Han, Jinkyu; Zhu, Yuqi; Jaye, Cherno; Liu, Haiqing; Li, Zhuo -Qun; Taylor, Gordon T.; Fischer, Daniel A.; Appenzeller, Joerg; Zhu, Ruiping

    2015-11-16

    As a model system for understanding charge transfer in novel architectural designs for solar cells, double-walled carbon nanotube (DWNT)CdSe quantum dot (QD) (QDs with average diameters of 2.3, 3.0, and 4.1 nm) heterostructures have been fabricated. The individual nanoscale building blocks were successfully attached and combined using a hole-trapping thiol linker molecule, i.e., 4-mercaptophenol (MTH), through a facile, noncovalent ?? stacking attachment strategy. Transmission electron microscopy confirmed the attachment of QDs onto the external surfaces of the DWNTs. We herein demonstrate a meaningful and unique combination of near-edge X-ray absorption fine structure (NEXAFS) and Raman spectroscopies bolstered by complementary electrical transport measurements in order to elucidate the synergistic interactions between CdSe QDs and DWNTs, which are facilitated by the bridging MTH molecules that can scavenge photoinduced holes and potentially mediate electron redistribution between the conduction bands in CdSe QDs and the C 2p-derived states of the DWNTs. Specifically, we correlated evidence of charge transfer as manifested by (i) changes in the NEXAFS intensities of ?* resonance in the C K-edge and Cd M3-edge spectra, (ii) a perceptible outer tube G-band downshift in frequency in Raman spectra, as well as (iii) alterations in the threshold characteristics present in transport data as a function of CdSe QD deposition onto the DWNT surface. Furthermore, the separate effects of (i) varying QD sizes and (ii) QD coverage densities on the electron transfer were independently studied.

  7. Science-based design of stable quantum dots for energy-efficient lighting

    SciTech Connect (OSTI)

    Martin, James E.; Rohwer, Lauren E. S.; van Swol, Frank B.; Zhou, Xiaowang; Lu, Ping

    2015-09-01

    II-VI quantum dots, such as CdSe and CdTe, are attractive as downconversion materials for solid-state lighting, because of their narrow linewidth, tunable emission. However, for these materials to have acceptable quantum yields (QYs) requires that they be coated with a II-VI shell material whose valence band offset serves to confine the hole to the core. Confinement prevents the hole from accessing surface traps that lead to nonradiative decay of the exciton. Examples of such hole-confined core/shell QDs include CdTe/CdSe and CdSe/CdS. Unfortunately, the shell can also cause problems due to lattice mismatch, which ranges from 4-6% for systems of interest. This lattice mismatch can create significant interface energies at the heterojunction and places the core under radial compression and the shell under tangential tension. At elevated temperatures (~240°C) interfacial diffusion can relax these stresses, as can surface reconstruction, which can expose the core, creating hole traps. But such high temperatures favor the hexagonal Wurtzite structure, which has lower QY than the cubic zinc blende structure, which can be synthesized at lower temperatures, ~140°C. In the absence of alloying the core/shell structure can become metastable, or even unstable, if the shell is too thick. This can cause result in an irregular shell or even island growth. But if the shell is too thin thermallyactivated transport of the hole to surface traps can occur. In our LDRD we have developed a fundamental atomistic modeling capability, based on Stillinger-Weber and Bond-Order potentials we developed for the entire II-VI class. These pseudo-potentials have enabled us to conduct large-scale atomistic simulations that have led to the computation of phase diagrams of II-VI QDs. These phase diagrams demonstrate that at elevated temperatures the zinc blende phase of CdTe with CdSe grown on it epitaxially becomes thermodynamically unstable due to alloying. This is accompanied by a loss of hole confinement and a severe drop in the QY and emission lifetime, which is confirmed experimentally for the zinc blende core/shell QDs prepared at low temperatures. These QDs have QYs as high as 95%, which makes them very attractive for lighting. Finally, to address strain relaxation in these materials we developed a model for misfit dislocation formation that we have validated through atomistic simulations.

  8. Research Highlight

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

    Improved Daytime Precipitable Water Vapor from Vaisala Radiosonde Humidity Sensors Download a printable PDF Submitter: Cady-Pereira, K. E., Atmospheric and Environmental Research, Inc. Mlawer, E. J., Atmospheric & Environmental Research, Inc. Turner, D. D., National Oceanic and Atmospheric Administration Shephard, M. W., Atmospheric and Environmental Research, Inc. Clough, S. A., Atmospheric and Environmental Research, Inc. Area of Research: Atmospheric Thermodynamics and Vertical Structures

  9. Sustainable Transportation Program 2011 Annual Report

    SciTech Connect (OSTI)

    Vaughan, Kathi H

    2012-06-01

    Highlights of selected research and development efforts at Oak Ridge National Laboratory funded by the Vehicle Technologies Program, Biomass Program, and Hydrogen and Fuel Cells Program of the Department of Energy, Office of Energy Efficiency and Renewable Energy; and the Department of Transportation.

  10. Observation of the Kondo effect in a spin-3/2 hole quantum dot

    SciTech Connect (OSTI)

    Klochan, O.; Micolich, A. P.; Hamilton, A. R.; Trunov, K.; Reuter, D.; Wieck, A. D.

    2013-12-04

    We report the observation of the Kondo effect in a spin-3/2 hole quantum dot formed near pinch-off in a GaAs quantum wire. We clearly observe two distinctive hallmarks of quantum dot Kondo physics. First, the zero-bias peak in the differential conductance splits an in-plane magnetic field and the splitting is independent of gate voltage. Second, the splitting rate is twice as large as that for the lowest one-dimensional subband. We show that the Zeeman splitting of the zero-bias peak is highly anisotropic and attribute this to the strong spin-orbit interaction for holes in GaAs.

  11. Density-Dependent Carrier Dynamics in a Quantum Dots-in-a-Well

    Office of Scientific and Technical Information (OSTI)

    Heterostructure. (Journal Article) | SciTech Connect Density-Dependent Carrier Dynamics in a Quantum Dots-in-a-Well Heterostructure. Citation Details In-Document Search Title: Density-Dependent Carrier Dynamics in a Quantum Dots-in-a-Well Heterostructure. Abstract not provided. Authors: Chow, Weng W. ; Prasankumar, Rohit P. ; Urayama, Junji ; Attaluri, R. S. ; Shenoi, R. V. ; Krishna, S. ; Taylor, A. J. Publication Date: 2010-11-01 OSTI Identifier: 1121942 Report Number(s): SAND2010-7836J

  12. Temperature dependent photoluminescence and micromapping of multiple stacks InAs quantum dots

    SciTech Connect (OSTI)

    Xu, Ming Jaffr, Alexandre Alvarez, Jos Kleider, Jean-Paul Boutchich, Mohamed; Jittrong, Apichat; Chokamnuai, Thitipong; Panyakeow, Somsak; Kanjanachuchai, Songphol

    2015-02-27

    We utilized temperature dependent photoluminescence (PL) techniques to investigate 1, 3 and 5 stack InGaAs quantum dots (QDs) grown on cross-hatch patterns. PL mapping can well reproduce the QDs distribution as AFM and position dependency of QD growth. It is possible to observe crystallographic dependent PL. The temperature dependent spectra exhibit the QDs energy distribution which reflects the size and shape. The inter-dot carrier coupling effect is observed and translated as a red shift of 120mV on the [110] direction peak is observed at 30K on 1 stack with regards to 3 stacks samples, which is assigned to lateral coupling.

  13. Temperature dependency of the emission properties from positioned In(Ga)As/GaAs quantum dots

    SciTech Connect (OSTI)

    Braun, T.; Schneider, C.; Maier, S.; Forchel, A.; Hfling, S.; Kamp, M.; Igusa, R.; Iwamoto, S.; Arakawa, Y.

    2014-09-15

    In this letter we study the influence of temperature and excitation power on the emission linewidth from site-controlled InGaAs/GaAs quantum dots grown on nanoholes defined by electron beam lithography and wet chemical etching. We identify thermal electron activation as well as direct exciton loss as the dominant intensity quenching channels. Additionally, we carefully analyze the effects of optical and acoustic phonons as well as close-by defects on the emission linewidth by means of temperature and power dependent micro-photoluminescence on single quantum dots with large pitches.

  14. g-factor anisotropy in nanowire-based InAs quantum dots

    SciTech Connect (OSTI)

    D'Hollosy, Samuel; Fábián, Gábor; Baumgartner, Andreas; Schönenberger, Christian; Nygård, Jesper

    2013-12-04

    The determination and control of the electron g-factor in semiconductor quantum dots (QDs) are fundamental prerequisites in modern concepts of spintronics and spin-based quantum computation. We study the dependence of the g-factor on the orientation of an external magnetic field in quantum dots (QDs) formed between two metallic contacts on stacking fault free InAs nanowires. We extract the g-factor from the splitting of Kondo resonances and find that it varies continuously in the range between |g*| = 5 and 15.

  15. Next-Generation "Giant" Quantum Dots: Performance-Engineered for

    Energy Savers [EERE]

    Lighting | Department of Energy "Giant" Quantum Dots: Performance-Engineered for Lighting Next-Generation "Giant" Quantum Dots: Performance-Engineered for Lighting Lead Performer: Los Alamos National Laboratory - Los Alamos, NM Partners: Cree, Inc. - Durham, NC DOE Total Funding: $1,000,366 Cost Share: $250,006 Project Term: 7/1/15 - 6/30/17 Funding Opportunity: SSL R&D Funding Opportunity Announcement (FOA) (DE-FOA-0001171) Project Objective This project seeks to

  16. Fermilab | Visit Fermilab | Transportation

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

    Transportation Transportation to and from Chicago O'Hare Airport or Midway Airport is available by limousine, taxi or car rental. Transportation to and from the Geneva local commuter Metra train station on the Union Pacific West line is available by taxi or Pace Call-n-Ride. Car rental All of the usual rental companies (such as Hertz, Avis, Budget and National) are located at the airports. For the best price, we recommend Ace Rent-a-Car at O'Hare Airport, telephone 1-800-243-3443 or

  17. National Transportation Stakeholders Forum

    Office of Environmental Management (EM)

    Transportation Stakeholders Forum May 14-16, 2013 Tuesday, May 14 7:00 am - 5:00 pm Registration Niagara Foyer 7:00 am - 7:45 am Breakfast and Networking Grand A 8:00 am - 10:00 am National Updates for Transportation Stakeholder Groups and Guests - Panel Grand BC Moderator: John Giarrusso Jr., MA Emergency Management Agency / Northeast High-Level Radioactive Waste Transportation Task Force Co-Chair US Department of Energy, Office of Environmental Management - Steve O'Connor, Director, Office of

  18. Transportation and Vehicle Energy Modeling | Argonne National Laboratory

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

    Transportation and Vehicle Energy Modeling Transportation and Vehicle Energy Modeling For the past 15 years, Argonne has been at the forefront of research in energy-efficient transportation. In recent years, the vehicle technologies have become increasingly complex with the introduction of new powertrain configurations (such as electrified vehicles), new component technologies (such as advanced transmissions and engines) and control strategies (such eco-routing). In addition, with increased

  19. Effects on the Physical Environment (Hydrodynamics, Sediment Transport, and

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

    Water Quality) | Department of Energy Sediment Transport, and Water Quality) Effects on the Physical Environment (Hydrodynamics, Sediment Transport, and Water Quality) Effects on the Physical Environment (Hydrodynamics, Sediment Transport, and Water Quality) File 56_tools_methods_to_measure_predict_envrionmental_impacts_snl_roberts.pptx More Documents & Publications FY 09 Lab Call: Research & Assessment for MHK Development 2014 Water Power Program Peer Review Compiled Presentations:

  20. Chapter 8: Advancing Clean Transportation and Vehicle Systems and Technologies

    Office of Environmental Management (EM)

    8: Advancing Clean Transportation and Vehicle Systems and Technologies September 2015 Quadrennial Technology Review 8 Advancing Clean Transportation and Vehicle Systems and Technologies Issues and RDD&D Opportunities  Transportation accounts for 10% of U.S. gross domestic product and provides essential services throughout the economy and for quality of life. It also represents 70% of all U.S. petroleum use and 27% of U.S. greenhouse gas (GHG) emissions.  Research opportunities to

  1. EBS Radionuclide Transport Abstraction

    SciTech Connect (OSTI)

    J.D. Schreiber

    2005-08-25

    The purpose of this report is to develop and analyze the engineered barrier system (EBS) radionuclide transport abstraction model, consistent with Level I and Level II model validation, as identified in ''Technical Work Plan for: Near-Field Environment and Transport: Engineered Barrier System: Radionuclide Transport Abstraction Model Report Integration'' (BSC 2005 [DIRS 173617]). The EBS radionuclide transport abstraction (or EBS RT Abstraction) is the conceptual model used in the total system performance assessment for the license application (TSPA-LA) to determine the rate of radionuclide releases from the EBS to the unsaturated zone (UZ). The EBS RT Abstraction conceptual model consists of two main components: a flow model and a transport model. Both models are developed mathematically from first principles in order to show explicitly what assumptions, simplifications, and approximations are incorporated into the models used in the TSPA-LA. The flow model defines the pathways for water flow in the EBS and specifies how the flow rate is computed in each pathway. Input to this model includes the seepage flux into a drift. The seepage flux is potentially split by the drip shield, with some (or all) of the flux being diverted by the drip shield and some passing through breaches in the drip shield that might result from corrosion or seismic damage. The flux through drip shield breaches is potentially split by the waste package, with some (or all) of the flux being diverted by the waste package and some passing through waste package breaches that might result from corrosion or seismic damage. Neither the drip shield nor the waste package survives an igneous intrusion, so the flux splitting submodel is not used in the igneous scenario class. The flow model is validated in an independent model validation technical review. The drip shield and waste package flux splitting algorithms are developed and validated using experimental data. The transport model considers advective transport and diffusive transport from a breached waste package. Advective transport occurs when radionuclides that are dissolved or sorbed onto colloids (or both) are carried from the waste package by the portion of the seepage flux that passes through waste package breaches. Diffusive transport occurs as a result of a gradient in radionuclide concentration and may take place while advective transport is also occurring, as well as when no advective transport is occurring. Diffusive transport is addressed in detail because it is the sole means of transport when there is no flow through a waste package, which may dominate during the regulatory compliance period in the nominal and seismic scenarios. The advective transport rate, when it occurs, is generally greater than the diffusive transport rate. Colloid-facilitated advective and diffusive transport is also modeled and is presented in detail in Appendix B of this report.

  2. The Geography of Transport Systems-Maritime Transportation |...

    Open Energy Info (EERE)

    report Website: people.hofstra.edugeotransengch3enconc3ench3c4en.html Cost: Free Language: English References: Maritime Transportation1 "Maritime transportation, similar to...

  3. Transportation Data Programs:Transportation Energy Data Book...

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

    Energy Data Book,Vehicle Technologies Market Report, and VT Fact of the Week Transportation Data Programs:Transportation Energy Data Book,Vehicle Technologies ...

  4. Transportation Baseline Report

    SciTech Connect (OSTI)

    Fawcett, Ricky Lee; Kramer, George Leroy Jr.

    1999-12-01

    The National Transportation Program 1999 Transportation Baseline Report presents data that form a baseline to enable analysis and planning for future Department of Energy (DOE) Environmental Management (EM) waste and materials transportation. In addition, this Report provides a summary overview of DOEs projected quantities of waste and materials for transportation. Data presented in this report were gathered as a part of the IPABS Spring 1999 update of the EM Corporate Database and are current as of July 30, 1999. These data were input and compiled using the Analysis and Visualization System (AVS) which is used to update all stream-level components of the EM Corporate Database, as well as TSD System and programmatic risk (disposition barrier) information. Project (PBS) and site-level IPABS data are being collected through the Interim Data Management System (IDMS). The data are presented in appendices to this report.

  5. Accident resistant transport container

    DOE Patents [OSTI]

    Andersen, John A. (Albuquerque, NM); Cole, James K. (Albuquerque, NM)

    1980-01-01

    The invention relates to a container for the safe air transport of plutonium having several intermediate wood layers and a load spreader intermediate an inner container and an outer shell for mitigation of shock during a hypothetical accident.

  6. Transportation | Open Energy Information

    Open Energy Info (EERE)

    Data From AEO2011 report . Market Trends From 2009 to 2035, transportation sector energy consumption grows at an average annual rate of 0.6 percent (from 27.2 quadrillion Btu...

  7. PBA Transportation Websites

    Broader source: Energy.gov [DOE]

    PBA Transportation Websites presented to the DOE Systems Analysis Workshop held in Washington, D.C. July 28-29, 2004 to discuss and define role of systems analysis in DOE Hydrogen Program.

  8. New Research Projects > Research > The Energy Materials Center at Cornell

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

    New Research Projects In This Section Seed Project - Coates Research Initiative - Abruña Research Initiative - Schlom New Research Projects Transport Dynamics and Carbonation Tolerance in Solution Processable Ionomers: Enabling a Viable Alkaline Anion Exchange Membrane Fuel Cell Molecularly Designed Architectures for High Energy Density Li/S Batteries Oxide Superlattice Approach to Water Splitting

  9. Transportation Data Archiving

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

    Transportation Data Archiving This email address is being protected from spambots. You need JavaScript enabled to view it. - TRACC Director Background Urban and regional transportation planning and operations applications, (e.g. traffic modeling) require a large volume of accurate traffic-related data for a wide range of conditions. Significant real-time data on traffic volumes, highway construction, accidents, weather, airline flights, commuter and rail schedules, etc., are recorded each day by

  10. Fluid transport container

    DOE Patents [OSTI]

    DeRoos, Bradley G. (41 James St., Sequim, WA 98382); Downing, Jr., John P. (260 Kala Heights Dr., Port Townsand, WA 98368); Neal, Michael P. (921 Amberly Pl., Columbus, OH 43220)

    1995-01-01

    An improved fluid container for the transport, collection, and dispensing of a sample fluid that maintains the fluid integrity relative to the conditions of the location at which it is taken. More specifically, the invention is a fluid sample transport container that utilizes a fitment for both penetrating and sealing a storage container under controlled conditions. Additionally, the invention allows for the periodic withdrawal of portions of the sample fluid without contamination or intermixing from the environment surrounding the sample container.

  11. Transportation Politics and Policy

    Gasoline and Diesel Fuel Update (EIA)

    Reducing Greenhouse Gas Emissions from U.S. Transportation Steven Plotkin, Argonne National Laboratory (co-author is David Greene of Oak Ridge) 2011 EIA Energy Conference May 26-27, 2011 Washington, DC Overview  Presentation based on recent report from the Pew Center on Global Climate Change  Task: Assess the potential to substantially reduce transportation's GHG emissions by 2035 & 2050.  Base Case: Annual Energy Outlook 2010 Reference Case, extended to 2050  Three scenarios

  12. Transportation fuels from wood

    SciTech Connect (OSTI)

    Baker, E.G.; Elliott, D.C.; Stevens, D.J.

    1980-01-01

    The various methods of producing transportation fuels from wood are evaluated in this paper. These methods include direct liquefaction schemes such as hydrolysis/fermentation, pyrolysis, and thermochemical liquefaction. Indirect liquefaction techniques involve gasification followed by liquid fuels synthesis such as methanol synthesis or the Fischer-Tropsch synthesis. The cost of transportation fuels produced by the various methods are compared. In addition, three ongoing programs at Pacific Northwest Laboratory dealing with liquid fuels from wood are described.

  13. National Transportation Stakeholders Forum

    Office of Environmental Management (EM)

    Save the Date! National Transportation Stakeholders Forum 2015 Annual Meeting May 12-14, 2015 Embassy Suites Albuquerque, New Mexico The U.S. Department of Energy (DOE) is pleased to announce the 2015 Annual Meeting of the National Transportation Stakeholders' Forum (NTSF). The Annual Meeting will take place from May 12-14 at the Embassy Suites in Albuquerque, New Mexico. DOE will be hosting this year's meeting in partnership with the Western Governors' Association, Western Interstate Energy

  14. Transportation and Program Management Services

    Office of Environmental Management (EM)

    Atlanta, Georgia Transportation and Program Management Services Secured Transportation Services, LLC Founded: December, 2003 ff Staff: 7 Experience: Over 145 years combined experience in Nuclear Transportation, Security, HP & Operations Services Transportation The largest Transportation Coordinators of Spent Nuclear Fuel in North America On-Site, Hands-On Assistance (Before & During both Loading & Transport) P d A i t (W iti d/ R i ) Procedure Assistance (Writing and/or Review)

  15. Research Highlight

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

    SPartICus Submitter: Mishra, S., DOE - SunShot Initiative, AAAS S&T Policy Fellow Mitchell, D. L., Desert Research Institute Area of Research: General Circulation and Single...

  16. CASL - Radiation Transport Methods Update

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

    Radiation Transport Methods Update The Radiation Transport Methods (RTM) focus area is responsible for the development of methods, algorithms, and implementations of radiation...

  17. Badger Transport | Open Energy Information

    Open Energy Info (EERE)

    Transport Jump to: navigation, search Name: Badger Transport Place: Clintonville, Wisconsin Zip: 54929 Product: Heavy haul and specialty trucking company active in the US Midwest....

  18. Transportation Resources | Advanced Photon Source

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

    Transportation Resources The following means of transportation are available for getting to Argonne. Airports Argonne is located within 25 miles of two major Chicago airports:...

  19. Washington: Integrated Transportation Programs & Coordinated...

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

    Integrated Transportation Programs & Coordinated Regional Planning Washington: Integrated Transportation Programs & Coordinated Regional Planning November 6, 2013 - 5:42pm Addthis ...

  20. TiO2 Nanotubes with a ZnO Thin Energy Barrier for Improved Current Efficiency of CdSe Quantum-Dot-Sensitized Solar Cells

    SciTech Connect (OSTI)

    Lee, W.; Kang, S. H.; Kim, J. Y.; Kolekar, G. B.; Sung, Y. E.; Han, S. H.

    2009-01-01

    This paper reports the formation of a thin ZnO energy barrier between a CdSe quantum dot (Q dots) sensitizer and TiO{sub 2} nanotubes (TONTs) for improved current efficiency of Q dot-sensitized solar cells. The formation of a ZnO barrier between TONTs and the Q dot sensitizer increased the short-circuit current under illumination and also reduced the dark current in a dark environment. The power conversion efficiency of Q dot-sensitized TONT solar cells increased by 25.9% in the presence of the ZnO thin layer due to improved charge-collecting efficiency and reduced recombination.