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Sample records for water tunnel overseeing

  1. Carderock 3-ft Variable Pressure Cavitation Water Tunnel | Open...

    Open Energy Info (EERE)

    3-ft Variable Pressure Cavitation Water Tunnel Jump to: navigation, search Basic Specifications Facility Name Carderock 3-ft Variable Pressure Cavitation Water Tunnel Overseeing...

  2. Appendix E: Chapter 5 - Overseeing a Project

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

    E April 2016 APPENDIX E: Chapter 5 - Overseeing a Project Appendix E-1: Technical Assistance Tasks for Field Representatives (Medium- Cost Option) Appendix E-2: Sample Request for Proposal (RFP) and Contract to Solicit Field Representatives (Project Facilitators) Appendix E-3: Project Screening Appendix E-4: Sample Feasibility Study Appendix E-5: Project Tracking Log Appendix E-6: Technical Assistance Checklist Guidelines for a State ESPC Program E-1 | page 1 April 2016 APPENDIX E-1: Technical

  3. guidelines_develop_staff_oversee_state_energy_savings_perf_contract...

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

    More Documents & Publications Developing, Staffing, and Overseeing a State Energy Savings Performance Contracting Program ESPC Pricing and Financing for State and...

  4. Quantum Tunneling of Water in Beryl. A New State of the Water...

    Office of Scientific and Technical Information (OSTI)

    Quantum Tunneling of Water in Beryl. A New State of the Water Molecule Citation Details In-Document Search This content will become publicly available on April 22, 2017 Title: ...

  5. Quantum Tunneling of Water in Beryl. A New State of the Water Molecule

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

    Kolesnikov, Alexander I.; Reiter, George F.; Choudhury, Narayani; Prisk, Timothy R.; Mamontov, Eugene; Podlesnyak, Andrey; Ehlers, George; Seel, Andrew G.; Wesolowski, David J.; Anovitz, Lawrence M.

    2016-04-22

    When using neutron scattering and ab initio simulations, we document the discovery of a new “quantum tunneling state” of the water molecule confined in 5 Å channels in the mineral beryl, characterized by extended proton and electron delocalization. We observed a number of peaks in the inelastic neutron scattering spectra that were uniquely assigned to water quantum tunneling. Additionally, the water proton momentum distribution was measured with deep inelastic neutron scattering, which directly revealed coherent delocalization of the protons in the ground state.

  6. Energy Savings Performance Contracting: Guidelines for Developing, Staffing, and Overseeing a State Program

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

    Energy Savings Performance Contracting: Guidelines for Developing, Staffing, and Overseeing a State Program April 2016 ESPC Guidelines for Developing Staffing, and Overseeing a State ESPC Program April 2016 Disclaimer: This document is a guide to best practices when establishing an ESPC program. This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any

  7. Dose calculations for the concrete water tunnels at 190-C Area, Hanford Site

    SciTech Connect (OSTI)

    Kamboj, S.; Yu, C.

    1997-01-01

    The RESRAD-BUILD code was used to calculate the radiological dose from the contaminated concrete water tunnels at the 190-C Area at the Hanford Site. Two exposure scenarios, recreationist and maintenance worker, were considered. A residential scenario was not considered because the material was assumed to be left intact (i.e., the concrete would not be rubbleized because the location would not be suitable for construction of a house). The recreationist was assumed to use the tunnel for 8 hours per day for 1 week as an overnight shelter. The maintenance worker was assumed to spend 20 hours per year working in the tunnel. Six exposure pathways were considered in calculating the dose. Three external exposure pathways involved penetrating radiation emitted directly from the contaminated tunnel floor, emitted from radioactive particulates deposited on the tunnel floor, and resulting from submersion in airborne radioactive particulates. Three internal exposure pathways involved inhalation of airborne radioactive particulates; inadvertent direct ingestion of removable, contaminated material on the tunnel floor; and inadvertent indirect ingestion of airborne particulates deposited on the tunnel floor. The gradual removal of surface contamination over time and the ingrowth of decay products were considered in calculating the dose at different times. The maximum doses were estimated to be 1.5 mrem/yr for the recreationist and 0.34 mrem/yr for the maintenance worker.

  8. Energy Savings Performance Contracting: Guidelines for Developing, Staffing, and Overseeing a State Program

    Broader source: Energy.gov [DOE]

    The Energy Savings Performance Contracting Guidelines for Developing, Staffing, and Overseeing a State Program (Program Guidelines) provide information, best practices, and resources on how to develop an Energy Savings Performance Contracting (ESPC) program. The goal is to increase acceptance and use of ESPC by state and local governments to achieve large-scale and comprehensive energy-saving projects.

  9. Scanning Tunneling Microscopy and Theoretical Study of Water Adsorption on Fe3O4: Implications for Catalysis

    SciTech Connect (OSTI)

    Rim, Kwang T.; Eom, Daejin; Chan, Siu-Wai; Flytzani-Stephanopoulos, Maria; Flynn, George; Wen, Xiaodong; Batista, Enrique R.

    2012-10-23

    The reduced surface of a natural Hematite single crystal a-Fe2O3(0001) sample has multiple surface domains with di!erent terminations, Fe2O3(0001), FeO(111), and Fe3O4(111). The adsorption of water on this surface was investigated via Scanning Tunneling Microscopy (STM) and first-principle theoretical simulations. Water species are observed only on the Fe-terminated Fe3O4(111) surface at temperatures up to 235 K. Between 235 and 245 K we observed a change in the surface species from intact water molecules and hydroxyl groups bound to the surface to only hydroxyl groups atop the surface terminating FeIII cations. This indicates a low energy barrier for water dissociation on the surface of Fe3O4 that is supported by our theoretical computations. Our first principles simulations con"rm the identity of the surface species proposed from the STM images, finding that the most stable state of a water molecule is the dissociated one (OH + H), with OH atop surface terminating FeIII sites and H atop under-coordinated oxygen sites. Attempts to simulate reaction of the surface OH with coadsorbed CO fail because the only binding sites for CO are the surface FeIII atoms, which are blocked by the much more strongly bound OH. In order to promote this reaction we simulated a surface decorated with gold atoms. The Au adatoms are found to cap the under-coordinated oxygen sites and dosed CO is found to bind to the Au adatom. This newly created binding site for CO not only allows for coexistence of CO and OH on the surface of Fe3O4 but also provides colocation between the two species. These two factors are likely promoters of catalytic activity on Au/Fe3O4(111) surfaces.

  10. Channel tunnel

    ScienceCinema (OSTI)

    None

    2011-04-25

    Jacques Lemley, américain et "chief executif" parle du projet de l'Eurotunnel - tunnel sous la manche

  11. Tunnel | Open Energy Information

    Open Energy Info (EERE)

    Tunnel Jump to: navigation, search Retrieved from "http:en.openei.orgwindex.php?titleTunnel&oldid596391" Feedback Contact needs updating Image needs updating Reference...

  12. In Situ Observation of Water Dissociation with Lattice Incorporation at FeO Particle Edges Using Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy

    SciTech Connect (OSTI)

    Deng, Xingyi; Lee, Junseok; Wang, Congjun; Matranga, Christopher; Aksoy, Funda; Liu, Zhi

    2011-03-15

    The dissociation of H2O and formation of adsorbed hydroxyl groups, on FeO particles grown on Au(111) were identified with in situ,: X:ray photoelectron spectroscopy (XPS) at water pressures ranging from 3 x 10-8 to 0.1 Torr. The facile dissociation of H2O takes place at FeO particle edges, and it was successfully observed in situ With atomically resolved scanning tunneling microscopy (STM). The in situ STM studies show that adsorbed hydroxyl groups were formed exclusively along the edges of the FeO particles with the 0 atom becoming directly incorporated into the oxide crystalline lattice The STM results are consistent with coordinatively unsaturated ferrous (CUF) sites along the FeO particle edge causing the observed reactivity with H2O. Our results also directly illustrate how structural defects and under.-coordinated sites participate in chemical reactions.

  13. Tunnel closure calculations

    SciTech Connect (OSTI)

    Moran, B.; Attia, A.

    1995-07-01

    When a deeply penetrating munition explodes above the roof of a tunnel, the amount of rubble that falls inside the tunnel is primarily a function of three parameters: first the cube-root scaled distance from the center of the explosive to the roof of the tunnel. Second the material properties of the rock around the tunnel, and in particular the shear strength of that rock, its RQD (Rock Quality Designator), and the extent and orientation of joints. And third the ratio of the tunnel diameter to the standoff distance (distance between the center of explosive and the tunnel roof). The authors have used CALE, a well-established 2-D hydrodynamic computer code, to calculate the amount of rubble that falls inside a tunnel as a function of standoff distance for two different tunnel diameters. In particular they calculated three of the tunnel collapse experiments conducted in an iron ore mine near Kirkeness, Norway in the summer of 1994. The failure model that they used in their calculations combines an equivalent plastic strain criterion with a maximum tensile strength criterion and can be calibrated for different rocks using cratering data as well as laboratory experiments. These calculations are intended to test and improve the understanding of both the Norway Experiments and the ACE (Array of conventional Explosive) phenomenology.

  14. Scanning tunneling microscope nanoetching method

    DOE Patents [OSTI]

    Li, Yun-Zhong; Reifenberger, Ronald G.; Andres, Ronald P.

    1990-01-01

    A method is described for forming uniform nanometer sized depressions on the surface of a conducting substrate. A tunneling tip is used to apply tunneling current density sufficient to vaporize a localized area of the substrate surface. The resulting depressions or craters in the substrate surface can be formed in information encoding patterns readable with a scanning tunneling microscope.

  15. Property:Overseeing Organization | Open Energy Information

    Open Energy Info (EERE)

    Laboratory, Inc + Alden Wave Basin + Alden Research Laboratory, Inc + B Breakwater Research Facility + United States Army Corp of Engineers (ERDC) + Bucknell Hydraulic Flume...

  16. Appendix E: Chapter 5 - Overseeing a Project

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

    ... Guidelines for a State ESPC Program E-2 | page 21 April 2016 EXHIBIT B PROJECT TRACKING Updated: CUSTOMER NAME PROJECT ID: CONTACT INFO: REFERRED BY: SERVICES PROVIDED DATE ...

  17. Penn Large Water Tunnel | Open Energy Information

    Open Energy Info (EERE)

    designs with verification and Validation studies. Integrated DisplayGraphics Microsoft Windows based systems Other Data Capabilites State-of-the-art non-invasive flow...

  18. Penn Small Water Tunnel | Open Energy Information

    Open Energy Info (EERE)

    designs with verification and Validation studies. Integrated DisplayGraphics Microsoft Windows based systems Other Data Capabilites State-of-the-art non-invasive flow...

  19. Wind Tunnel Specifications | Department of Energy

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

    Wind Tunnel Specifications Wind Tunnel Specifications This document shows the basic wind tunnel configuration. Please use these specifications when designing test turbines for the Collegiate Wind Competition. Wind Tunnel Specifications (191.74 KB) More Documents & Publications Collegiate Wind Competition 2014 Rules and Regulations Collegiate Wind Competition 2016 Rules and Regulations Building the Basic PVC Wind Turbine

  20. Flatback airfoil wind tunnel experiment.

    SciTech Connect (OSTI)

    Mayda, Edward A.; van Dam, C.P.; Chao, David D.; Berg, Dale E.

    2008-04-01

    A computational fluid dynamics study of thick wind turbine section shapes in the test section of the UC Davis wind tunnel at a chord Reynolds number of one million is presented. The goals of this study are to validate standard wind tunnel wall corrections for high solid blockage conditions and to reaffirm the favorable effect of a blunt trailing edge or flatback on the performance characteristics of a representative thick airfoil shape prior to building the wind tunnel models and conducting the experiment. The numerical simulations prove the standard wind tunnel corrections to be largely valid for the proposed test of 40% maximum thickness to chord ratio airfoils at a solid blockage ratio of 10%. Comparison of the computed lift characteristics of a sharp trailing edge baseline airfoil and derived flatback airfoils reaffirms the earlier observed trend of reduced sensitivity to surface contamination with increasing trailing edge thickness.

  1. Collegiate Wind Competition Wind Tunnel Specifications

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

    Tunnel Specifications The basic wind tunnel configuration is shown below. The dimensions of the test chamber are 4 ft x 4 ft x 8 ft (48 in x 48 in x 96 in). There are inlet and outlet components of the wind tunnel that extend beyond the test chamber as shown. The tunnel has a "draw down" configuration. That is, the air is "sucked through" the test section-entering at the left, exiting at the right-with the draw down being induced by the fan on the right side of the tunnel. A

  2. Single-contact tunneling thermometry

    DOE Patents [OSTI]

    Maksymovych, Petro

    2016-02-23

    A single-contact tunneling thermometry circuit includes a tunnel junction formed between two objects. Junction temperature gradient information is determined based on a mathematical relationship between a target alternating voltage applied across the junction and the junction temperature gradient. Total voltage measured across the junction indicates the magnitude of the target alternating voltage. A thermal gradient is induced across the junction. A reference thermovoltage is measured when zero alternating voltage is applied across the junction. An increasing alternating voltage is applied while measuring a thermovoltage component and a DC rectification voltage component created by the applied alternating voltage. The target alternating voltage is reached when the thermovoltage is nullified or doubled by the DC rectification voltage depending on the sign of the reference thermovoltage. Thermoelectric current and current measurements may be utilized in place of the thermovoltage and voltage measurements. The system may be automated with a feedback loop.

  3. Observing remnants by fermions' tunneling

    SciTech Connect (OSTI)

    Chen, D.Y.; Wu, H.W.; Yang, H. E-mail: iverwu@uestc.edu.cn

    2014-03-01

    The standard Hawking formula predicts the complete evaporation of black holes. In this paper, we introduce effects of quantum gravity into fermions' tunneling from Reissner-Nordstrom and Kerr black holes. The quantum gravity effects slow down the increase of Hawking temperatures. This property naturally leads to a residue mass in black hole evaporation. The corrected temperatures are affected by the quantum numbers of emitted fermions. Meanwhile, the temperature of the Kerr black hole is a function of ? due to the rotation.

  4. Troll Phase I pipelines: Tie-ins to the subsea tunnel

    SciTech Connect (OSTI)

    Hove, F.; Kuhlmann, H.

    1995-12-31

    Subsea approaches to the Norwegian coast are characterized by very rugged topography. Landfall of offshore pipelines therefore often require dedicated subsea tunnel and pipeline tie in concepts. To land the 36 inch and 40 inch offshore pipelines associated with the Troll Phase 1 development, a 4 km long landfall tunnel was constructed terminating at a water depth of 165 m with vertical shaft connections to the seabed. This paper describes the design of the Troll Phase 1 tie-ins of offshore to tunnel pipeline sections. These comprise two main elements, i.e. 180 Te tie-in spools -- which are installed between the offshore pipelines and the piercing shafts -- and prefabricated 450 Te riser bundles -- which are installed into the vertical tunnel piercing shafts.

  5. Polycrystalline silicon passivated tunneling contacts for high...

    Office of Scientific and Technical Information (OSTI)

    efficiency silicon solar cells Citation Details In-Document Search Title: Polycrystalline silicon passivated tunneling contacts for high efficiency silicon solar cells Authors: ...

  6. Assessment of Scaled Rotors for Wind Tunnel Experiments.

    SciTech Connect (OSTI)

    Maniaci, David Charles; Kelley, Christopher Lee; Chiu, Phillip

    2015-07-01

    Rotor design and analysis work has been performed to support the conceptualization of a wind tunnel test focused on studying wake dynamics. This wind tunnel test would serve as part of a larger model validation campaign that is part of the Department of Energy Wind and Water Power Program’s Atmosphere to electrons (A2e) initiative. The first phase of this effort was directed towards designing a functionally scaled rotor based on the same design process and target full-scale turbine used for new rotors for the DOE/SNL SWiFT site. The second phase focused on assessing the capabilities of an already available rotor, the G1, designed and built by researchers at the Technical University of München.

  7. Enhancement of tunnel magnetoresistance in magnetic tunnel junction by a superlattice barrier

    SciTech Connect (OSTI)

    Chen, C. H.; Hsueh, W. J.

    2014-01-27

    Tunnel magnetoresistance of magnetic tunnel junction improved by a superlattice barrier composed of alternate layers of a nonmagnetic metal and an insulator is proposed. The forbidden band of the superlattice is used to predict the low transmission range in the superlattice barrier. By forbidding electron transport in the anti-parallel configuration, the tunnel magnetoresistance is enhanced in the superlattice junction. The results show that the tunnel magnetoresistance ratio for a superlattice magnetic tunnel junction is greater than that for traditional single or double barrier junctions.

  8. New Flexible Channels for Room Temperature Tunneling Field Effect...

    Office of Scientific and Technical Information (OSTI)

    New Flexible Channels for Room Temperature Tunneling Field Effect Transistors Citation Details In-Document Search Title: New Flexible Channels for Room Temperature Tunneling Field ...

  9. Wind tunnel performance data for the Darrieus wind turbine with...

    Office of Scientific and Technical Information (OSTI)

    Wind tunnel performance data for the Darrieus wind turbine with NACA 0012 blades Citation Details In-Document Search Title: Wind tunnel performance data for the Darrieus wind ...

  10. Enhancing metal-insulator-insulator-metal tunnel diodes via defect enhanced direct tunneling

    SciTech Connect (OSTI)

    Alimardani, Nasir; Conley, John F.

    2014-08-25

    Metal-insulator-insulator-metal tunnel diodes with dissimilar work function electrodes and nanolaminate Al{sub 2}O{sub 3}-Ta{sub 2}O{sub 5} bilayer tunnel barriers deposited by atomic layer deposition are investigated. This combination of high and low electron affinity insulators, each with different dominant conduction mechanisms (tunneling and Frenkel-Poole emission), results in improved low voltage asymmetry and non-linearity of current versus voltage behavior. These improvements are due to defect enhanced direct tunneling in which electrons transport across the Ta{sub 2}O{sub 5} via defect based conduction before tunneling directly through the Al{sub 2}O{sub 3}, effectively narrowing the tunnel barrier. Conduction through the device is dominated by tunneling, and operation is relatively insensitive to temperature.

  11. Influence of quasiparticle multi-tunneling on the energy flow through the superconducting tunnel junction

    SciTech Connect (OSTI)

    Samedov, V. V.; Tulinov, B. M.

    2011-07-01

    Superconducting tunnel junction (STJ) detector consists of two layers of superconducting material separated by thin insulating barrier. An incident particle produces in superconductor excess nonequilibrium quasiparticles. Each quasiparticle in superconductor should be considered as quantum superposition of electron-like and hole-like excitations. This duality nature of quasiparticle leads to the effect of multi-tunneling. Quasiparticle starts to tunnel back and forth through the insulating barrier. After tunneling from biased electrode quasiparticle loses its energy via phonon emission. Eventually, the energy that equals to the difference in quasiparticle energy between two electrodes is deposited in the signal electrode. Because of the process of multi-tunneling, one quasiparticle can deposit energy more than once. In this work, the theory of branching cascade processes was applied to the process of energy deposition caused by the quasiparticle multi-tunneling. The formulae for the mean value and variance of the energy transferred by one quasiparticle into heat were derived. (authors)

  12. Methods for the fabrication of thermally stable magnetic tunnel junctions

    DOE Patents [OSTI]

    Chang, Y. Austin; Yang, Jianhua J.; Ladwig, Peter F.

    2009-08-25

    Magnetic tunnel junctions and method for making the magnetic tunnel junctions are provided. The magnetic tunnel junctions are characterized by a tunnel barrier oxide layer sandwiched between two ferromagnetic layers. The methods used to fabricate the magnetic tunnel junctions are capable of completely and selectively oxidizing a tunnel junction precursor material using an oxidizing gas containing a mixture of gases to provide a tunnel junction oxide without oxidizing the adjacent ferromagnetic materials. In some embodiments the gas mixture is a mixture of CO and CO.sub.2 or a mixture of H.sub.2 and H.sub.2O.

  13. Collegiate Wind Competition Wind Tunnel Specifications | Department of

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

    Energy Wind Tunnel Specifications Collegiate Wind Competition Wind Tunnel Specifications Collegiate Wind Competition Wind Tunnel Specifications Teams competing in the U.S. Department of Energy Collegiate Wind Competition must design a prototype wind turbine that fits inside the wind tunnel created to test the performance of each team's project. The tunnel has a "draw down" configuration, introduced by the fan, that sucks air through the box. There are two debris filters, one at

  14. Rock mechanics design in mining and tunneling

    SciTech Connect (OSTI)

    Bieniawski, Z.T.

    1984-01-01

    This book introduces the design process as applied to rock mechanics aspects of underground mining and tunneling. Topics covered include a historical perspective, the design process in engineering, empirical methods of design, observational methods of design, and guided design.

  15. Collegiate Wind Competition Wind Tunnel Specifications | Department...

    Office of Environmental Management (EM)

    Competition must design a prototype wind turbine that fits inside the wind tunnel created ... The wire mesh screen prevents turbine pieces from getting sucked into the fan unit. Basic ...

  16. Modeling direct interband tunneling. I. Bulk semiconductors

    SciTech Connect (OSTI)

    Pan, Andrew; Chui, Chi On

    2014-08-07

    Interband tunneling is frequently studied using the semiclassical Kane model, despite uncertainty about its validity. Revisiting the physical basis of this formula, we find that it neglects coupling to other bands and underestimates transverse tunneling. As a result, significant errors can arise at low and high fields for small and large gap materials, respectively. We derive a simple multiband tunneling model to correct these defects analytically without arbitrary parameters. Through extensive comparison with band structure and quantum transport calculations for bulk InGaAs, InAs, and InSb, we probe the accuracy of the Kane and multiband formulas and establish the superiority of the latter. We also show that the nonlocal average electric field should be used when applying either of these models to nonuniform potentials. Our findings are important for efficient analysis and simulation of bulk semiconductor devices involving tunneling.

  17. Carderock Subsonic Wind Tunnel | Open Energy Information

    Open Energy Info (EERE)

    Subsonic Wind Tunnel is a continuous flow, closed-circuit facility with a closed jet test section. Test models may be supported by strut mounts using the external balance or by...

  18. Semiconductor tunnel junction with enhancement layer

    DOE Patents [OSTI]

    Klem, John F.; Zolper, John C.

    1997-01-01

    The incorporation of a pseudomorphic GaAsSb layer in a runnel diode structure affords a new degree of freedom in designing runnel junctions for p-n junction device interconnects. Previously only doping levels could be varied to control the tunneling properties. This invention uses the valence band alignment band of the GaAsSb with respect to the surrounding materials to greatly relax the doping requirements for tunneling.

  19. Semiconductor tunnel junction with enhancement layer

    DOE Patents [OSTI]

    Klem, J.F.; Zolper, J.C.

    1997-10-21

    The incorporation of a pseudomorphic GaAsSb layer in a runnel diode structure affords a new degree of freedom in designing runnel junctions for p-n junction device interconnects. Previously only doping levels could be varied to control the tunneling properties. This invention uses the valence band alignment band of the GaAsSb with respect to the surrounding materials to greatly relax the doping requirements for tunneling. 5 figs.

  20. Property:Main Overseeing Organization | Open Energy Information

    Open Energy Info (EERE)

    ProjectsAlaska 7 + Hydro Green Energy + MHK ProjectsAlgiers Cutoff Project + MARMC Enterprises LLC + MHK ProjectsAlgiers Light Project + Free Flow Power Corporation + MHK...

  1. May 28, 2010: Chu helps oversee BP's "top kill" efforts

    Broader source: Energy.gov [DOE]

    May 28, 2010Secretary Chu concludes several days in Houston monitoring the “top kill” attempt to stop the oil well leak in the Gulf of Mexico, analyzing the data as it comes in and helping to...

  2. Josephson tunnel junction with polycrystalline silicon, germanium or silicon-germanium alloy tunneling barrier

    SciTech Connect (OSTI)

    Kroger, H.

    1980-09-02

    A Josephson tunnel junction device having niobium nitride superconductive electrodes includes a polycrystalline semiconductor tunnelling barrier therebetween comprised of silicon, germanium or an alloy thereof preferably deposited on the lower superconductive electrodes by chemical vapor deposition. The barrier height of the junction is precisely controlled by precision doping of the semiconductor material.

  3. Le LHC, un tunnel cosmique

    SciTech Connect (OSTI)

    2009-09-17

    Et si la lumière au bout du tunnel du LHC était cosmique ? En d’autres termes, qu’est-ce que le LHC peut nous apporter dans la connaissance de l’Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l’univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l’Univers ? La matière noire est-elle détectable au LHC ? L’énergie noire ? Pourquoi l’antimatière accumulée au CERN est-elle si rare dans l’Univers ? Et si le CERN a bâti sa réputation sur l’exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l’évolution cosmique ? Depuis une trentaine d’années, notre compréhension de l’univers dans ses plus grandes dimensions et l’appréhension de son comportement aux plus petites distances sont intimement liées : en quoi le LHC va-t-il tester expérimentalement cette vision unifiée ? Tout public, entrée libre / Réservations au +41 (0)22 767 76 76

  4. Le LHC, un tunnel cosmique

    ScienceCinema (OSTI)

    None

    2011-10-06

    Et si la lumière au bout du tunnel du LHC était cosmique ? En d?autres termes, qu?est-ce que le LHC peut nous apporter dans la connaissance de l?Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l?univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l?Univers ? La matière noire est-elle détectable au LHC ? L?énergie noire ? Pourquoi l?antimatière accumulée au CERN est-elle si rare dans l?Univers ? Et si le CERN a bâti sa réputation sur l?exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l?évolution cosmique ? Depuis une trentaine d?années, notre compréhension de l?univers dans ses plus grandes dimensions et l?appréhension de son comportement aux plus petites distances sont intimement liées : en quoi le LHC va-t-il tester expérimentalement cette vision unifiée ? Tout public, entrée libre / Réservations au +41 (0)22 767 76 76

  5. cern_lhc_tunnel.jpg | OSTI, US Dept of Energy Office of Scientific and

    Office of Scientific and Technical Information (OSTI)

    Technical Information cern_lhc_tunnel

  6. Electronic thermometry in tunable tunnel junction

    DOE Patents [OSTI]

    Maksymovych, Petro

    2016-03-15

    A tunable tunnel junction thermometry circuit includes a variable width tunnel junction between a test object and a probe. The junction width is varied and a change in thermovoltage across the junction with respect to the change in distance across the junction is determined. Also, a change in biased current with respect to a change in distance across the junction is determined. A temperature gradient across the junction is determined based on a mathematical relationship between the temperature gradient, the change in thermovoltage with respect to distance and the change in biased current with respect to distance. Thermovoltage may be measured by nullifying a thermoelectric tunneling current with an applied voltage supply level. A piezoelectric actuator may modulate the probe, and thus the junction width, to vary thermovoltage and biased current across the junction. Lock-in amplifiers measure the derivatives of the thermovoltage and biased current modulated by varying junction width.

  7. Method of fabricating a solar cell with a tunnel dielectric layer

    SciTech Connect (OSTI)

    Dennis, Tim; Harrington, Scott; Manning, Jane; Smith, David D.; Waldhauer, Ann

    2015-08-18

    Method of fabricating solar cells with tunnel dielectric layers are described. Solar cells with tunnel dielectric layers are also described.

  8. Method of fabricating a solar cell with a tunnel dielectric layer

    DOE Patents [OSTI]

    Dennis, Tim; Harrington, Scott; Manning, Jane; Smith, David D; Waldhauer, Ann

    2014-04-29

    Methods of fabricating solar cells with tunnel dielectric layers are described. Solar cells with tunnel dielectric layers are also described.

  9. Method of fabricating a solar cell with a tunnel dielectric layer

    DOE Patents [OSTI]

    Dennis, Tim; Harrington, Scott; Manning, Jane; Smith, David; Waldhauer, Ann

    2012-12-18

    Methods of fabricating solar cells with tunnel dielectric layers are described. Solar cells with tunnel dielectric layers are also described.

  10. A new technique to measure tunneling barrier height in solid...

    Office of Scientific and Technical Information (OSTI)

    A new technique to measure tunneling barrier height in solid media Citation Details In-Document Search Title: A new technique to measure tunneling barrier height in solid media ...

  11. HFiTT - Higgs Factory in Tevatron Tunnel (Technical Report) ...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: HFiTT - Higgs Factory in Tevatron Tunnel Citation Details In-Document Search Title: HFiTT - Higgs Factory in Tevatron Tunnel Authors: Chou, Weiren ; Mourou, ...

  12. Coherent revival of tunneling (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Coherent revival of tunneling Citation Details In-Document Search Title: Coherent revival of tunneling Authors: Hsu, Liang-Yan ; Rabitz, Herschel Publication Date: 2015-07-08 OSTI ...

  13. PP-99 St. Clair Tunnel Company | Department of Energy

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

    9 St. Clair Tunnel Company PP-99 St. Clair Tunnel Company Presidential Permit authorizong St. Clair Tunnel Company to construct, operate,a nd maintain eelctric transmission facilities at the U.S. - Canada Border PP-99 St. Clair Tunnel Company (1.08 MB) More Documents & Publications PP-48-3 El Paso Eelctric Company PP-90-1 Imperial Irrigation District PP-76 The Vermont Electric Transmission Company

  14. Fabrication of magnetic tunnel junctions with epitaxial and textured ferromagnetic layers

    DOE Patents [OSTI]

    Chang, Y. Austin; Yang, Jianhua Joshua

    2008-11-11

    This invention relates to magnetic tunnel junctions and methods for making the magnetic tunnel junctions. The magnetic tunnel junctions include a tunnel barrier oxide layer sandwiched between two ferromagnetic layers both of which are epitaxial or textured with respect to the underlying substrate upon which the magnetic tunnel junctions are grown. The magnetic tunnel junctions provide improved magnetic properties, sharper interfaces and few defects.

  15. 360° Inside a Wind Tunnel | Department of Energy

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

    360° Inside a Wind Tunnel 360° Inside a Wind Tunnel Addthis Experience what it's like inside a wind tunnel with with this video! (make sure to use your mouse or move your mobile phone around to get the full effect). Learn more about the U.S. Department of Energy Collegiate Wind Competition

  16. Resonant tunnelling in a quantum oxide superlattice

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

    Choi, Woo Seok; Lee, Sang A.; You, Jeong Ho; Lee, Suyoun; Lee, Ho Nyung

    2015-06-24

    Resonant tunneling is a quantum mechanical process that has long been attracting both scientific and technological attention owing to its intriguing underlying physics and unique applications for high-speed electronics. The materials system exhibiting resonant tunneling, however, has been largely limited to the conventional semiconductors, partially due to their excellent crystalline quality. Here we show that a deliberately designed transition metal oxide superlattice exhibits a resonant tunneling behaviour with a clear negative differential resistance. The tunneling occurred through an atomically thin, lanthanum δ- doped SrTiO3 layer, and the negative differential resistance was realized on top of the bi-polar resistance switching typicallymore » observed for perovskite oxide junctions. This combined process resulted in an extremely large resistance ratio (~105) between the high and low resistance states. Lastly, the unprecedentedly large control found in atomically thin δ-doped oxide superlattices can open a door to novel oxide-based high-frequency logic devices.« less

  17. Resonant tunnelling in a quantum oxide superlattice

    SciTech Connect (OSTI)

    Choi, Woo Seok; Lee, Sang A.; You, Jeong Ho; Lee, Suyoun; Lee, Ho Nyung

    2015-06-24

    Resonant tunneling is a quantum mechanical process that has long been attracting both scientific and technological attention owing to its intriguing underlying physics and unique applications for high-speed electronics. The materials system exhibiting resonant tunneling, however, has been largely limited to the conventional semiconductors, partially due to their excellent crystalline quality. Here we show that a deliberately designed transition metal oxide superlattice exhibits a resonant tunneling behaviour with a clear negative differential resistance. The tunneling occurred through an atomically thin, lanthanum δ- doped SrTiO3 layer, and the negative differential resistance was realized on top of the bi-polar resistance switching typically observed for perovskite oxide junctions. This combined process resulted in an extremely large resistance ratio (~105) between the high and low resistance states. Lastly, the unprecedentedly large control found in atomically thin δ-doped oxide superlattices can open a door to novel oxide-based high-frequency logic devices.

  18. B-Target Room Tunnel Redesigned

    SciTech Connect (OSTI)

    Esfandiari, Reza; /San Jose State U. /SLAC

    2010-08-25

    Several groups at SLAC National Accelerator Laboratory are currently working on a RF Modulator prototype for a future linear collider known as the International Linear Collider (ILC). The ILC runs using about a 1000 Klystrons which create high power carrier waves for the particle acceleration. Klystrons receive their electrical input power from modulators. In order to move beyond the prototype phase, the laboratory might expand its ground base further down a tunnel located at the End Station B (ESB) in order to house four new Klystron Modulator Test Stations. This area is known as the B-Target Room Tunnel, and the task was to redesign the tunnel layout for the upcoming changes. The project first began by collecting substantial amount of information about the prototyped project, the tunnel and the researchers feedback of what they would like to see in the upcoming design. Subsequent to numerous planning and presentations, one particular design was. Calculations for this design were then performed for the most complex aspects of the project. Based on the results of the calculations, specific sample beams, welds, bolts and materials were chosen for the possible future construction.

  19. DOE - NNSA/NFO -- News & Views Tunnel Test

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

    Tunnel Tests Span 35 years of Nevada Test Site History Photo - Rainer a 1.7 kiloton tunnel test On August 10, 1957, a zero-yield safety experiment named "Saturn" was detonated in C-Tunnel. Since then tests have been conducted in 16 different tunnels in Rainier Mesa on the Nevada Test Site. Today, there is only one active tunnel used by the Defense Nuclear Agency (DNA). The DNA evaluates the effects of nuclear weapons explosions, thermal radiation, blast, shock, x-rays and gamma rays,

  20. Carderock 2-ft Variable Pressure Cavitation Water Tunnel | Open...

    Open Energy Info (EERE)

    is a vertical plane, closed recirculating, variable-speed, variable-pressure, open jet test section, closed jet test section, and semi-rectangular test section. Towing...

  1. Superpoissonian shot noise in organic magnetic tunnel junctions

    SciTech Connect (OSTI)

    Cascales, Juan Pedro; Martinez, Isidoro; Aliev, Farkhad G.; Hong, Jhen-Yong; Lin, Minn-Tsong; Szczepański, Tomasz; Dugaev, Vitalii K.; Barnaś, Józef

    2014-12-08

    Organic molecules have recently revolutionized ways to create new spintronic devices. Despite intense studies, the statistics of tunneling electrons through organic barriers remains unclear. Here, we investigate conductance and shot noise in magnetic tunnel junctions with 3,4,9,10-perylene-teracarboxylic dianhydride (PTCDA) barriers a few nm thick. For junctions in the electron tunneling regime, with magnetoresistance ratios between 10% and 40%, we observe superpoissonian shot noise. The Fano factor exceeds in 1.5–2 times the maximum values reported for magnetic tunnel junctions with inorganic barriers, indicating spin dependent bunching in tunneling. We explain our main findings in terms of a model which includes tunneling through a two level (or multilevel) system, originated from interfacial bonds of the PTCDA molecules. Our results suggest that interfaces play an important role in the control of shot noise when electrons tunnel through organic barriers.

  2. Scanning tunneling microscope assembly, reactor, and system

    DOE Patents [OSTI]

    Tao, Feng; Salmeron, Miquel; Somorjai, Gabor A

    2014-11-18

    An embodiment of a scanning tunneling microscope (STM) reactor includes a pressure vessel, an STM assembly, and three spring coupling objects. The pressure vessel includes a sealable port, an interior, and an exterior. An embodiment of an STM system includes a vacuum chamber, an STM reactor, and three springs. The three springs couple the STM reactor to the vacuum chamber and are operable to suspend the scanning tunneling microscope reactor within the interior of the vacuum chamber during operation of the STM reactor. An embodiment of an STM assembly includes a coarse displacement arrangement, a piezoelectric fine displacement scanning tube coupled to the coarse displacement arrangement, and a receiver. The piezoelectric fine displacement scanning tube is coupled to the coarse displacement arrangement. The receiver is coupled to the piezoelectric scanning tube and is operable to receive a tip holder, and the tip holder is operable to receive a tip.

  3. Highly Charged Ion (HCI) Modified Tunnel Junctions

    SciTech Connect (OSTI)

    Pomeroy, J. M.; Grube, H. [Atomic Physics Division, National Institute of Standards and Technology (NIST) 100 Bureau Dr., MS 8423, Gaithersburg, MD 20899-8423 (United States)

    2009-03-10

    The neutralization energy carried by highly charged ions (HCIs) provides an alternative method for localizing energy on a target's surface, producing features and modifying surfaces with fluences and kinetic energy damage that are negligible compared to singly ionized atoms. Since each HCI can deposit an enormous amount of energy into a small volume of the surface (e.g., Xe{sup 44+} delivers 51 keV of neutralization energy per HCI), each individual HCI's interaction with the target can produce a nanoscale feature. Many studies of HCI-surface features have characterized some basic principles of this unique ion-surface interaction, but the activity reported here has been focused on studying ensembles of HCI features in ultra-thin insulating films by fabricating multi-layer tunnel junction devices. The ultra-thin insulating barriers allow current to flow by tunneling, providing a very sensitive means of detecting changes in the barrier due to highly charged ion irradiation and, conversely, HCI modification provides a method of finely tuning the transparency of the tunnel junctions that spans several orders of magnitude for devices produced from a single process recipe. Systematic variation of junction bias, temperature, magnetic field and other parameters provides determination of the transport mechanism, defect densities, and magnetic properties of these nano-features and this novel approach to device fabrication.

  4. Enhancement of Spin-transfer torque switching via resonant tunneling

    SciTech Connect (OSTI)

    Chatterji, Niladri; Tulapurkar, Ashwin A.; Muralidharan, Bhaskaran

    2014-12-08

    We propose the use of resonant tunneling as a route to enhance the spin-transfer torque switching characteristics of magnetic tunnel junctions. The proposed device structure is a resonant tunneling magnetic tunnel junction based on a MgO-semiconductor heterostructure sandwiched between a fixed magnet and a free magnet. Using the non-equilibrium Green's function formalism coupled self consistently with the Landau-Lifshitz-Gilbert-Slonczewski equation, we demonstrate enhanced tunnel magneto-resistance characteristics as well as lower switching voltages in comparison with traditional trilayer devices. Two device designs based on MgO based heterostructures are presented, where the physics of resonant tunneling leads to an enhanced spin transfer torque thereby reducing the critical switching voltage by up to 44%. It is envisioned that the proof-of-concept presented here may lead to practical device designs via rigorous materials and interface studies.

  5. Self-contained instrument for measuring subterranean tunnel wall deflection

    DOE Patents [OSTI]

    Rasmussen, Donald Edgar; Hof, Jr., Peter John

    1978-01-01

    The deflection of a subterranean tunnel is measured with a rod-like, self-contained instrument that is adapted to be inserted into a radially extending bore of the tunnel adjacent an end of the tunnel where the tunnel is being dug. One end of the instrument is anchored at the end of the bore remote from the tunnel wall, while the other end of the intrument is anchored adjacent the end of the wall in proximity to the tunnel wall. The two ends of the instrument are linearly displaceable relative to each other; the displacement is measured by a transducer means mounted on the instrument. Included in the instrument is a data storage means including a paper tape recorder periodically responsive to a parallel binary signal indicative of the measured displacement.

  6. Ferroelectric tunneling element and memory applications which utilize the tunneling element

    DOE Patents [OSTI]

    Kalinin, Sergei V. [Knoxville, TN; Christen, Hans M. [Knoxville, TN; Baddorf, Arthur P. [Knoxville, TN; Meunier, Vincent [Knoxville, TN; Lee, Ho Nyung [Oak Ridge, TN

    2010-07-20

    A tunneling element includes a thin film layer of ferroelectric material and a pair of dissimilar electrically-conductive layers disposed on opposite sides of the ferroelectric layer. Because of the dissimilarity in composition or construction between the electrically-conductive layers, the electron transport behavior of the electrically-conductive layers is polarization dependent when the tunneling element is below the Curie temperature of the layer of ferroelectric material. The element can be used as a basis of compact 1R type non-volatile random access memory (RAM). The advantages include extremely simple architecture, ultimate scalability and fast access times generic for all ferroelectric memories.

  7. New Flexible Channels for Room Temperature Tunneling Field Effect...

    Office of Scientific and Technical Information (OSTI)

    Consistent semiconductor-like transport behaviors under various bending conditions are detected by scanning tunneling spectroscopy in a transmission electron microscopy system ...

  8. Mitigation of wind tunnel wall interactions in subsonic cavity flows

    SciTech Connect (OSTI)

    Wagner, Justin L.; Casper, Katya Marie; Beresh, Steven J.; Henfling, John F.; Spillers, Russell Wayne; Pruett, Brian Owen Matthew

    2015-03-06

    In this study, the flow over an open aircraft bay is often represented in a wind tunnel with a cavity. In flight, this flow is unconfined, though in experiments, the cavity is surrounded by wind tunnel walls. If untreated, wind tunnel wall effects can lead to significant distortions of cavity acoustics in subsonic flows. To understand and mitigate these cavitytunnel interactions, a parametric approach was taken for flow over an L/D = 7 cavity at Mach numbers 0.60.8. With solid tunnel walls, a dominant cavity tone was observed, likely due to an interaction with a tunnel duct mode. Furthermore, an acoustic liner opposite the cavity decreased the amplitude of the dominant mode and its harmonics, a result observed by previous researchers. Acoustic dampeners were also placed in the tunnel sidewalls, which further decreased the dominant mode amplitudes and peak amplitudes associated with nonlinear interactions between cavity modes. This then indicates that cavity resonance can be altered by tunnel sidewalls and that spanwise coupling should be addressed when conducting subsonic cavity experiments. Though mechanisms for dominant modes and nonlinear interactions likely exist in unconfined cavity flows, these effects can be amplified by the wind tunnel walls.

  9. Stationary bubbles and their tunneling channels toward trivial...

    Office of Scientific and Technical Information (OSTI)

    We investigate the dynamics and tunneling channels of true vacuum bubbles for various tensions. In particular, in line with the idea of superposition of geometries, we build a ...

  10. Mitigation of wind tunnel wall interactions in subsonic cavity flows

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

    Wagner, Justin L.; Casper, Katya Marie; Beresh, Steven J.; Henfling, John F.; Spillers, Russell Wayne; Pruett, Brian Owen Matthew

    2015-03-06

    In this study, the flow over an open aircraft bay is often represented in a wind tunnel with a cavity. In flight, this flow is unconfined, though in experiments, the cavity is surrounded by wind tunnel walls. If untreated, wind tunnel wall effects can lead to significant distortions of cavity acoustics in subsonic flows. To understand and mitigate these cavity–tunnel interactions, a parametric approach was taken for flow over an L/D = 7 cavity at Mach numbers 0.6–0.8. With solid tunnel walls, a dominant cavity tone was observed, likely due to an interaction with a tunnel duct mode. Furthermore, anmore » acoustic liner opposite the cavity decreased the amplitude of the dominant mode and its harmonics, a result observed by previous researchers. Acoustic dampeners were also placed in the tunnel sidewalls, which further decreased the dominant mode amplitudes and peak amplitudes associated with nonlinear interactions between cavity modes. This then indicates that cavity resonance can be altered by tunnel sidewalls and that spanwise coupling should be addressed when conducting subsonic cavity experiments. Though mechanisms for dominant modes and nonlinear interactions likely exist in unconfined cavity flows, these effects can be amplified by the wind tunnel walls.« less

  11. Mitigation of wind tunnel wall interactions in subsonic cavity flows

    SciTech Connect (OSTI)

    Wagner, Justin L.; Casper, Katya Marie; Beresh, Steven J.; Henfling, John F.; Spillers, Russell Wayne; Pruett, Brian Owen Matthew

    2015-03-06

    In this study, the flow over an open aircraft bay is often represented in a wind tunnel with a cavity. In flight, this flow is unconfined, though in experiments, the cavity is surrounded by wind tunnel walls. If untreated, wind tunnel wall effects can lead to significant distortions of cavity acoustics in subsonic flows. To understand and mitigate these cavity–tunnel interactions, a parametric approach was taken for flow over an L/D = 7 cavity at Mach numbers 0.6–0.8. With solid tunnel walls, a dominant cavity tone was observed, likely due to an interaction with a tunnel duct mode. Furthermore, an acoustic liner opposite the cavity decreased the amplitude of the dominant mode and its harmonics, a result observed by previous researchers. Acoustic dampeners were also placed in the tunnel sidewalls, which further decreased the dominant mode amplitudes and peak amplitudes associated with nonlinear interactions between cavity modes. This then indicates that cavity resonance can be altered by tunnel sidewalls and that spanwise coupling should be addressed when conducting subsonic cavity experiments. Though mechanisms for dominant modes and nonlinear interactions likely exist in unconfined cavity flows, these effects can be amplified by the wind tunnel walls.

  12. Boundary conformal field theory and tunneling of edge quasiparticles...

    Office of Scientific and Technical Information (OSTI)

    CONTACTS; ELECTRON CORRELATION; HALL EFFECT; ISING MODEL; QUANTUM FIELD THEORY; TOPOLOGY; TUNNEL EFFECT Word Cloud More Like This Full Text Journal Articles DOI: 10.1016...

  13. Competition between cotunneling, Kondo effect, and direct tunneling in discontinuous high-anisotropy magnetic tunnel junctions

    SciTech Connect (OSTI)

    Ciudad D.; Arena D.; We, Z.-C.; Hindmarch, A.T.; Negusse, E.; Han, X.-F.Han; Marrows, C.H.

    2012-06-07

    The transition between Kondo and Coulomb blockade effects in discontinuous double magnetic tunnel junctions is explored as a function of the size of the CoPt magnetic clusters embedded between AlO{sub x} tunnel barriers. A gradual competition between cotunneling enhancement of the tunneling magnetoresistance (TMR) and the TMR suppression due to the Kondo effect has been found in these junctions, with both effects having been found to coexist even in the same sample. It is possible to tune between these two states with temperature (at a temperature far below the cluster blocking temperature). In addition, when further decreasing the size of the CoPt clusters, another gradual transition between the Kondo effect and direct tunneling between the electrodes takes place. This second transition shows that the spin-flip processes found in junctions with impurities in the barrier are in fact due to the Kondo effect. A simple theoretical model able to account for these experimental results is proposed.

  14. Optical isolation via unidirectional resonant photon tunneling

    SciTech Connect (OSTI)

    Moccia, Massimo; Castaldi, Giuseppe; Galdi, Vincenzo; Al, Andrea; Engheta, Nader

    2014-01-28

    We show that tri-layer structures combining epsilon-negative and magneto-optical material layers can exhibit unidirectional resonant photon tunneling phenomena that can discriminate between circularly polarized (CP) waves of given handedness impinging from opposite directions, or between CP waves with different handedness impinging from the same direction. This physical principle, which can also be interpreted in terms of a Fabry-Perot-type resonance, may be utilized to design compact optical isolators for CP waves. Within this framework, we derive simple analytical conditions and design formulae, and quantitatively assess the isolation performance, also taking into account the unavoidable imperfections and nonidealities.

  15. Direct tunneling through high-κ amorphous HfO{sub 2}: Effects...

    Office of Scientific and Technical Information (OSTI)

    Citation Details In-Document Search Title: Direct tunneling ... We report first principles modeling of quantum tunneling ... OSTI Identifier: 22308723 Resource Type: Journal Article ...

  16. Sensor integration study for a shallow tunnel detection system.

    SciTech Connect (OSTI)

    Yee, Mark L.; Abbott, Robert E.; Bonal, Nedra; Elbring, Gregory Jay; Senglaub, Michael E.

    2010-02-01

    During the past several years, there has been a growing recognition of the threats posed by the use of shallow tunnels against both international border security and the integrity of critical facilities. This has led to the development and testing of a variety of geophysical and surveillance techniques for the detection of these clandestine tunnels. The challenges of detection of these tunnels arising from the complexity of the near surface environment, the subtlety of the tunnel signatures themselves, and the frequent siting of these tunnels in urban environments with a high level of cultural noise, have time and again shown that any single technique is not robust enough to solve the tunnel detection problem in all cases. The question then arises as to how to best combine the multiple techniques currently available to create an integrated system that results in the best chance of detecting these tunnels in a variety of clutter environments and geologies. This study utilizes Taguchi analysis with simulated sensor detection performance to address this question. The analysis results show that ambient noise has the most effect on detection performance over the effects of tunnel characteristics and geological factors.

  17. Observation of Soliton Tunneling Phenomena and Soliton Ejection

    SciTech Connect (OSTI)

    Barak, Assaf; Peleg, Or; Segev, Mordechai; Stucchio, Chris; Soffer, Avy

    2008-04-18

    We study, theoretically and experimentally, the nonlinear dynamics of a wave packet launched inside a trap potential. Increasing the power of the wave packet transforms its dynamics from linear tunneling through a potential barrier, to soliton tunneling, and eventually, above a well-defined threshold, to the ejection of a soliton from the potential trap.

  18. Emptying and filling a tunnel bronze

    SciTech Connect (OSTI)

    Marley, Peter M.; Abtew, Tesfaye A.; Farley, Katie E.; Horrocks, Gregory A.; Dennis, Robert V.; Zhang, Peihong; Banerjee, Sarbajit

    2015-01-13

    The classical orthorhombic layered phase of V2O5 has long been regarded as the thermodynamic sink for binary vanadium oxides and has found great practical utility as a result of its open framework and easily accessible redox states. Herein, we exploit a cation-exchange mechanism to synthesize a new stable tunnel-structured polymorph of V2O5 (ζ-V2O5) and demonstrate the subsequent ability of this framework to accommodate Li and Mg ions. The facile extraction and insertion of cations and stabilization of the novel tunnel framework is facilitated by the nanometer-sized dimensions of the materials, which leads to accommodation of strain without amorphization. The topotactic approach demonstrated here indicates not just novel intercalation chemistry accessible at nanoscale dimensions but also suggests a facile synthetic route to ternary vanadium oxide bronzes (MxV2O5) exhibiting intriguing physical properties that range from electronic phase transitions to charge ordering and superconductivity.

  19. Pyrotechnic ignition studies using a gun tunnel

    SciTech Connect (OSTI)

    Evans, N.A.

    1989-01-01

    A gun tunnel is being used to investigate the ignition characteristics of center-hole iron/potassium perchlorate thermal battery discs. Details are given of the construction, operation, and data reduction method for the gun tunnel. To simulate an igniter, this system can readily produce a pulse of hot argon at maximum pressures and temperatures up to P/sub max/ = 8 MPa and T/sub max/ = 4000K, respectively, with flow times of the order of 3 msec. For a single battery disc, a segment of the ignition boundary was found to lie in the region of T/sub max/ = 1200 to 1300K and 0.7 MPa < P/sub max/ < 2.0 MPa. The results also showed two types of ignition: prompt ignition, requiring an average delivered enthalpy /ovr /Delta/H//sub ig/ = 6 cal during an average flow time /ovr /Delta/t//sub ig/ = 0.7 msec, and delayed ignition, with /ovr /Delta/H//sub ig/ = 16 cal and /ovr /Delta/t//sub ig/ = 2.4 msec. In addition, near an ignition boundary, high speed motion photography showed the ignition delay increased to 6 msec with significant spatial non-uniformity. 1 ref., 6 figs.

  20. Emptying and filling a tunnel bronze

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

    Marley, Peter M.; Abtew, Tesfaye A.; Farley, Katie E.; Horrocks, Gregory A.; Dennis, Robert V.; Zhang, Peihong; Banerjee, Sarbajit

    2015-01-13

    The classical orthorhombic layered phase of V2O5 has long been regarded as the thermodynamic sink for binary vanadium oxides and has found great practical utility as a result of its open framework and easily accessible redox states. Herein, we exploit a cation-exchange mechanism to synthesize a new stable tunnel-structured polymorph of V2O5 (ζ-V2O5) and demonstrate the subsequent ability of this framework to accommodate Li and Mg ions. The facile extraction and insertion of cations and stabilization of the novel tunnel framework is facilitated by the nanometer-sized dimensions of the materials, which leads to accommodation of strain without amorphization. The topotacticmore » approach demonstrated here indicates not just novel intercalation chemistry accessible at nanoscale dimensions but also suggests a facile synthetic route to ternary vanadium oxide bronzes (MxV2O5) exhibiting intriguing physical properties that range from electronic phase transitions to charge ordering and superconductivity.« less

  1. Natural convection in tunnels at Yucca Mountain and impact on drift seepage

    SciTech Connect (OSTI)

    Halecky, N.; Birkholzer, J.T.; Peterson, P.

    2010-04-15

    The decay heat from radioactive waste that is to be disposed in the once proposed geologic repository at Yucca Mountain (YM) will significantly influence the moisture conditions in the fractured rock near emplacement tunnels (drifts). Additionally, large-scale convective cells will form in the open-air drifts and will serve as an important mechanism for the transport of vaporized pore water from the fractured rock in the drift center to the drift end. Such convective processes would also impact drift seepage, as evaporation could reduce the build up of liquid water at the tunnel wall. Characterizing and understanding these liquid water and vapor transport processes is critical for evaluating the performance of the repository, in terms of water-induced canister corrosion and subsequent radionuclide containment. To study such processes, we previously developed and applied an enhanced version of TOUGH2 that solves for natural convection in the drift. We then used the results from this previous study as a time-dependent boundary condition in a high-resolution seepage model, allowing for a computationally efficient means for simulating these processes. The results from the seepage model show that cases with strong natural convection effects are expected to improve the performance of the repository, since smaller relative humidity values, with reduced local seepage, form a more desirable waste package environment.

  2. Soil erosion rates caused by wind and saltating sand stresses in a wind tunnel

    SciTech Connect (OSTI)

    Ligotke, M.W.

    1993-02-01

    Wind erosion tests were performed in a wind tunnel in support of the development of long-term protective barriers to cap stabilized waste sites at the Hanford Site. Controlled wind and saltating sand erosive stresses were applied to physical models of barrier surface layers to simulate worst-case eolian erosive stresses. The goal of these tests was to provide information useful to the design and evaluation of the surface layer composition of an arid-region waste site barrier concept that incorporates a deep fine-soil reservoir. A surface layer composition is needed that will form an armor resistant to eolian erosion during periods of extreme dry climatic conditions, especially when such conditions result in the elimination or reduction of vegetation by water deprivation or wildfire. Because of the life span required of Hanford waste barriers, it is important that additional work follow these wind tunnel studies. A modeling effort is planned to aid the interpretation of test results with respect to the suitability of pea gravel to protect the finite-soil reservoir during long periods of climatic stress. It is additionally recommended that wind tunnel tests be continued and field data be obtained at prototype or actual barrier sites. Results wig contribute to barrier design efforts and provide confidence in the design of long-term waste site caps for and regions.

  3. Soil erosion rates from mixed soil and gravel surfaces in a wind tunnel

    SciTech Connect (OSTI)

    Ligotke, M.W.; Klopfer, D.C.

    1990-08-01

    Protective barriers have been identified as integral components of plans to isolate defense waste on the Hanford Site. The use of natural materials to construct protective barriers over waste site is being considered. Design requirements for protective barriers include preventing exposure of buried waste, and restricting penetration or percolation of surface waters through the waste zone. Studies were initiated to evaluate the effects of wind erosion on candidate protective barrier surfaces. A wind tunnel was used to provide controlled erosive stresses and to investigate the erosive effects of wind forces on proposed surface layers for protective barriers. Mixed soil and gravel surfaces were prepared and tested for resistance to wind erosion at the Pacific Northwest Laboratory Aerosol Wind Tunnel Research Facility. These tests were performed to investigate surface deflation caused by suspension of soil from various surface layer configurations and to provide a comparison of the relative resistance of the different surfaces to wind erosion. Planning, testing, and analyzing phases of this wind erosion project were coordinated with other tasks supporting the development of protective barriers. These tasks include climate-change predictions, field studies and modeling efforts. This report provides results of measurements of deflation caused by wind forces over level surfaces. Section 2.0 reviews surface layer characteristics and previous relevant studies on wind erosion, describes effects of erosion, and discusses wind tunnel modeling. Materials and methods of the wind tunnel tests are discussed in Section 3.0. Results and discussion are presented in Section 4.0, and conclusions and recommendations Section 5.0. 53 refs., 29 figs., 7 tabs.

  4. Resonant tunneling of fluctuation Cooper pairs

    SciTech Connect (OSTI)

    Galda, Alexey; Mel'nikov, A. S.; Vinokur, V. M.

    2015-02-09

    Superconducting fluctuations have proved to be an irreplaceable source of information about microscopic and macroscopic material parameters that could be inferred from the experiment. According to common wisdom, the effect of thermodynamic fluctuations in the vicinity of the superconducting transition temperature, Tc, is to round off all of the sharp corners and discontinuities, which otherwise would have been expected to occur at Tc. Here we report the current spikes due to radiation-induced resonant tunneling of fluctuation Cooper pairs between two superconductors which grow even sharper and more pronounced upon approach to Tc. This striking effect offers an unprecedented tool for direct measurements of fluctuation Cooper pair lifetime, which is key to our understanding of the fluctuation regime, most notably to nature of the pseudogap state in high-temperature superconductors. Our finding marks a radical departure from the conventional view of superconducting fluctuations as a blurring and rounding phenomenon.

  5. Resonant tunneling of fluctuation Cooper pairs

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

    Galda, Alexey; Mel'nikov, A. S.; Vinokur, V. M.

    2015-02-09

    Superconducting fluctuations have proved to be an irreplaceable source of information about microscopic and macroscopic material parameters that could be inferred from the experiment. According to common wisdom, the effect of thermodynamic fluctuations in the vicinity of the superconducting transition temperature, Tc, is to round off all of the sharp corners and discontinuities, which otherwise would have been expected to occur at Tc. Here we report the current spikes due to radiation-induced resonant tunneling of fluctuation Cooper pairs between two superconductors which grow even sharper and more pronounced upon approach to Tc. This striking effect offers an unprecedented tool formore » direct measurements of fluctuation Cooper pair lifetime, which is key to our understanding of the fluctuation regime, most notably to nature of the pseudogap state in high-temperature superconductors. Our finding marks a radical departure from the conventional view of superconducting fluctuations as a blurring and rounding phenomenon.« less

  6. 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.

  7. Modeling direct interband tunneling. II. Lower-dimensional structures

    SciTech Connect (OSTI)

    Pan, Andrew; Chui, Chi On

    2014-08-07

    We investigate the applicability of the two-band Hamiltonian and the widely used Kane analytical formula to interband tunneling along unconfined directions in nanostructures. Through comparisons with kp and tight-binding calculations and quantum transport simulations, we find that the primary correction is the change in effective band gap. For both constant fields and realistic tunnel field-effect transistors, dimensionally consistent band gap scaling of the Kane formula allows analytical and numerical device simulations to approximate non-equilibrium Green's function current characteristics without arbitrary fitting. This allows efficient first-order calibration of semiclassical models for interband tunneling in nanodevices.

  8. Millikelvin cooling by heavy-fermion-based tunnel junctions

    SciTech Connect (OSTI)

    Prest, Martin; Min, Gao; Whall, Terry

    2015-12-28

    This paper addresses a high-performance electron-tunneling cooler based on a novel heavy-fermion/insulator/superconductor junction for millikelvin cooling applications. We show that the cooling performance of an electronic tunneling refrigerator could be significantly improved using a heavy-fermion metal to replace the normal metal in a conventional normal metal/insulator/superconductor junction. The calculation, based on typical parameters, indicates that, for a bath temperature of 300 mK, the minimum cooling temperature of an electron tunneling refrigerator is reduced from around 170 mK to below 50 mK if a heavy-fermion metal is employed in place of the normal metal. The improved cooling is attributed to an enhancement in electron tunneling due to the existence of a resonant density of states at the Fermi level.

  9. Resonant spin tunneling in randomly oriented nanospheres of Mn?? acetate

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

    Lendinez, S.; Billinge, S. J. L.; Zarzuela, R.; Tejada, J.; Terban, M. W.; Espin, J.; Imaz, I.; Maspoch, D.; Chudnovsky, E. M.

    2015-01-06

    We report measurements and theoretical analysis of resonant spin tunneling in randomly oriented nanospheres of a molecular magnet. Amorphous nanospheres of Mn?? acetate have been fabricated and characterized by chemical, infrared, TEM, X-ray, and magnetic methods. Magnetic measurements have revealed sharp tunneling peaks in the field derivative of the magnetization that occur at the typical resonant field values for the Mn?? acetate crystal in the field parallel to the easy axis.Theoretical analysis is provided that explains these observations. We argue that resonant spin tunneling in a molecular magnet can be established in a powder sample, without the need for amoresingle crystal and without aligning the easy magnetization axes of the molecules. This is confirmed by re-analyzing the old data on a powdered sample of non-oriented micron-size crystals of Mn?? acetate. Our findings can greatly simplify the selection of candidates for quantum spin tunneling among newly synthesized molecular magnets.less

  10. Computational design and analysis of flatback airfoil wind tunnel experiment.

    SciTech Connect (OSTI)

    Mayda, Edward A.; van Dam, C.P.; Chao, David D.; Berg, Dale E.

    2008-03-01

    A computational fluid dynamics study of thick wind turbine section shapes in the test section of the UC Davis wind tunnel at a chord Reynolds number of one million is presented. The goals of this study are to validate standard wind tunnel wall corrections for high solid blockage conditions and to reaffirm the favorable effect of a blunt trailing edge or flatback on the performance characteristics of a representative thick airfoil shape prior to building the wind tunnel models and conducting the experiment. The numerical simulations prove the standard wind tunnel corrections to be largely valid for the proposed test of 40% maximum thickness to chord ratio airfoils at a solid blockage ratio of 10%. Comparison of the computed lift characteristics of a sharp trailing edge baseline airfoil and derived flatback airfoils reaffirms the earlier observed trend of reduced sensitivity to surface contamination with increasing trailing edge thickness.

  11. Leading Edge Erosion Phase II Wind Tunnel Test Begins

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

    ... Wind tunnel testing is commencing for the second phase of the leading edge erosion project, which is a collaboration between Texas A&M, UC Davis, and Sandia. During the 2012 fiscal ...

  12. Vacuum gaps with small tunnel currents at large electric field...

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

    small tunnel currents at large electric field and its potential applications for energy storage, charge storage and power supplies. Friday, May 27, 2011 - 4:00pm SSRL Conference...

  13. Quantum tunneling resonant electron transfer process in Lorentzian plasmas

    SciTech Connect (OSTI)

    Hong, Woo-Pyo; Jung, Young-Dae

    2014-08-15

    The quantum tunneling resonant electron transfer process between a positive ion and a neutral atom collision is investigated in nonthermal generalized Lorentzian plasmas. The result shows that the nonthermal effect enhances the resonant electron transfer cross section in Lorentzian plasmas. It is found that the nonthermal effect on the classical resonant electron transfer cross section is more significant than that on the quantum tunneling resonant charge transfer cross section. It is shown that the nonthermal effect on the resonant electron transfer cross section decreases with an increase of the Debye length. In addition, the nonthermal effect on the quantum tunneling resonant electron transfer cross section decreases with increasing collision energy. The variation of nonthermal and plasma shielding effects on the quantum tunneling resonant electron transfer process is also discussed.

  14. From: Tunnell, Andrew To: Congestion Study Comments Subject:

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

    RE: Southern Companies" Comments to Draft National Electric Transmission Congestion Study Date: Monday, October 20, 2014 3:28:05 PM Attachments: DOE Congestion Comments.pdf I'm resending the comments described below as I did not receive any confirmation email. Please contact me at the number provided below if there is anything else that needs to be done in this regard. Thanks Andrew Tunnell From: Tunnell, Andrew Sent: Monday, October 20, 2014 2:17 PM To:

  15. Warning: Single Lane Tunnel Ahead | The Ames Laboratory

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

    Warning: Single Lane Tunnel Ahead A new theory shows that reactivity at catalytic sites inside narrow pores is controlled by how molecules move at the pore openings. Like cars approaching a single lane tunnel from which other cars are emerging, the movement of molecules depends on their distance into the pore; near the ends of the pores, exchange is rapid compared to further into the pores. Dynamics at the openings of these pores controls the penetration of reactants and thus overall conversion

  16. Electromagnetic squeezer for compressing squeezable electron tunneling junctions. Technical report

    SciTech Connect (OSTI)

    Moreland, J.; Hansma, P.K.

    1984-01-01

    The resistance of squeezable electron tunnel junctions (SET junctions) can be adjusted with an electromagnetic squeezer. For junctions immersed in liquid helium, the resistance is stable to approximately 0.1%. This stability is sufficient for measurements of superconducting energy gaps and for superconducting phonon spectroscopy out to 50 mV applied bias. Increased stability, especially at higher biases, will be necessary for inelastic electron tunneling spectroscopy.

  17. Electromagnetic squeezer for compressing squeezable electron tunnelling junctions

    SciTech Connect (OSTI)

    Moreland, J.; Hansma, P.K.

    1984-03-01

    The resistance of squeezable electron tunnel junctions (SET junctions) can be adjusted with an electromagnetic squeezer. For junctions immersed in liquid helium, the resistance is stable to approximately 0.1%. This stability is sufficient for measurements of superconducting energy gaps and for superconducting phonon spectroscopy out to 50-mV applied bias. Increased stability, especially at higher biases, will be necessary for inelastic electron tunnelling spectroscopy.

  18. Polycrystalline silicon passivated tunneling contacts for high efficiency

    Office of Scientific and Technical Information (OSTI)

    silicon solar cells (Journal Article) | SciTech Connect Journal Article: Polycrystalline silicon passivated tunneling contacts for high efficiency silicon solar cells Citation Details In-Document Search Title: Polycrystalline silicon passivated tunneling contacts for high efficiency silicon solar cells Authors: Nemeth, Bill ; Young, David L. ; Page, Matthew R. ; LaSalvia, Vincenzo ; Johnston, Steve ; Reedy, Robert ; Stradins, Paul Publication Date: 2016-03-01 OSTI Identifier: 1247961 Report

  19. Superconductive tunnel junction device and method of manufacture

    SciTech Connect (OSTI)

    Kroger, H.

    1983-12-20

    A Josephson tunnel junction device having niobium nitride superconductive electrodes includes a polycrystalline semiconductor tunneling barrier therebetween comprised of silicon, germanium, or an alloy thereof preferably deposited on the lower superconductive electrodes by vapor deposition. The barrier thickness of the junction is controlled by precision doping of the semiconductor material. The active junction is defined after the interfaces between the barrier material and the two superconductor lines are formed, retaining those active interfaces in fully unpolluted character.

  20. Tunneling magnetoresistance phenomenon utilizing graphene magnet electrode

    SciTech Connect (OSTI)

    Hashimoto, T.; Kamikawa, S.; Haruyama, J.; Soriano, D.; Pedersen, J. G.; Roche, S.

    2014-11-03

    Using magnetic rare-metals for spintronic devices is facing serious problems for the environmental contamination and the limited material-resource. In contrast, by fabricating ferromagnetic graphene nanopore arrays (FGNPAs) consisting of honeycomb-like array of hexagonal nanopores with hydrogen-terminated zigzag-type atomic structure edges, we reported observation of polarized electron spins spontaneously driven from the pore edge states, resulting in rare-metal-free flat-energy-band ferromagnetism. Here, we demonstrate observation of tunneling magnetoresistance (TMR) behaviors on the junction of cobalt/SiO{sub 2}/FGNPA electrode, serving as a prototype structure for future rare-metal free TMR devices using magnetic graphene electrodes. Gradual change in TMR ratios is observed across zero-magnetic field, arising from specified alignment between pore-edge- and cobalt-spins. The TMR ratios can be controlled by applying back-gate voltage and by modulating interpore distance. Annealing the SiO{sub 2}/FGNPA junction also drastically enhances TMR ratios up to ∼100%.

  1. Characterization of Superhydrophobic Surfaces for Anti-icing in a Low-Temperature Wind Tunnel

    SciTech Connect (OSTI)

    Swarctz, Christopher; Alijallis, Elias; Hunter, Scott Robert; Simpson, John T; Choi, Chang-Hwan

    2010-01-01

    In this study, a closed loop low-temperature wind tunnel was custom-built and uniquely used to investigate the anti-icing mechanism of superhydrophobic surfaces in regulated flow velocities, temperatures, humidity, and water moisture particle sizes. Silica nanoparticle-based hydrophobic coatings were tested as superhydrophobic surface models. During tests, images of ice formation were captured by a camera and used for analysis of ice morphology. Prior to and after wind tunnel testing, apparent contact angles of water sessile droplets on samples were measured by a contact angle meter to check degradation of surface superhydrophobicity. A simple peel test was also performed to estimate adhesion of ice on the surfaces. When compared to an untreated sample, superhydrophobic surfaces inhibited initial ice formation. After a period of time, random droplet strikes attached to the superhydrophobic surfaces and started to coalesce with previously deposited ice droplets. These sites appear as mounds of accreted ice across the surface. The appearance of the ice formations on the superhydrophobic samples is white rather than transparent, and is due to trapped air. These ice formations resemble soft rime ice rather than the transparent glaze ice seen on the untreated sample. Compared to untreated surfaces, the icing film formed on superhydrophobic surfaces was easy to peel off by shear flows.

  2. New Flexible Channels for Room Temperature Tunneling Field Effect Transistors

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

    Hao, Boyi; Asthana, Anjana; Hazaveh, Paniz Khanmohammadi; Bergstrom, Paul L.; Banyai, Douglas; Savaikar, Madhusudan A.; Jaszczak, John A.; Yap, Yoke Khin

    2016-02-05

    Tunneling field effect transistors (TFETs) have been proposed to overcome the fundamental issues of Si based transistors, such as short channel effect, finite leakage current, and high contact resistance. Unfortunately, most if not all TFETs are operational only at cryogenic temperatures. Here we report that iron (Fe) quantum dots functionalized boron nitride nanotubes (QDs-BNNTs) can be used as the flexible tunneling channels of TFETs at room temperatures. The electrical insulating BNNTs are used as the one-dimensional (1D) substrates to confine the uniform formation of Fe QDs on their surface as the flexible tunneling channel. Consistent semiconductor-like transport behaviors under variousmore » bending conditions are detected by scanning tunneling spectroscopy in a transmission electron microscopy system (insitu STM-TEM). Ultimately, as suggested by computer simulation, the uniform distribution of Fe QDs enable an averaging effect on the possible electron tunneling pathways, which is responsible for the consistent transport properties that are not sensitive to bending.« less

  3. H-CANYON AIR EXHAUST TUNNEL INSPECTION VEHICLE DEVELOPMENT

    SciTech Connect (OSTI)

    Minichan, R.; Fogle, R.; Marzolf, A.

    2011-05-24

    The H-Canyon at Savannah River Site is a large concrete structure designed for chemical separation processes of radioactive material. The facility requires a large ventilation system to maintain negative pressure in process areas for radioactive contamination control and personnel protection. The ventilation exhaust is directed through a concrete tunnel under the facility which is approximately five feet wide and 8 feet tall that leads to a sand filter and stack. Acidic vapors in the exhaust have had a degrading effect on the surface of the concrete tunnels. Some areas have been inspected; however, the condition of other areas is unknown. Experience from historical inspections with remote controlled vehicles will be discussed along with the current challenge of inspecting levels below available access points. The area of interest in the exhaust tunnel must be accessed through a 14 X 14 inch concrete plug in the floor of the hot gang valve corridor. The purpose for the inspection is to determine the condition of the inside of the air tunnel and establish if there are any structural concerns. Various landmarks, pipe hangers and exposed rebar are used as reference points for the structural engineers when evaluating the current integrity of the air tunnel.

  4. Ferromagnetic tunnel contacts to graphene: Contact resistance and spin signal

    SciTech Connect (OSTI)

    Cubukcu, M.; Laczkowski, P.; Vergnaud, C.; Marty, A.; Attan, J.-P.; Notin, L.; Vila, L. Jamet, M.; Martin, M.-B.; Seneor, P.; Anane, A.; Deranlot, C.; Fert, A.; Auffret, S.; Ducruet, C.

    2015-02-28

    We report spin transport in CVD graphene-based lateral spin valves using different magnetic contacts. We compared the spin signal amplitude measured on devices where the cobalt layer is directly in contact with the graphene to the one obtained using tunnel contacts. Although a sizeable spin signal (up to ?2 ?) is obtained with direct contacts, the signal is strongly enhanced (?400 ?) by inserting a tunnel barrier. In addition, we studied the resistance-area product (R.A) of a variety of contacts on CVD graphene. In particular, we compared the R.A products of alumina and magnesium oxide tunnel barriers grown by sputtering deposition of aluminum or magnesium and subsequent natural oxidation under pure oxygen atmosphere or by plasma. When using an alumina tunnel barrier on CVD graphene, the R.A product is high and exhibits a large dispersion. This dispersion can be highly reduced by using a magnesium oxide tunnel barrier, as for the R.A value. This study gives insight in the material quest for reproducible and efficient spin injection in CVD graphene.

  5. Tunnel junction enhanced nanowire ultraviolet light emitting diodes

    SciTech Connect (OSTI)

    Sarwar, A. T. M. Golam; May, Brelon J.; Deitz, Julia I.; Grassman, Tyler J.; McComb, David W.; Myers, Roberto C.

    2015-09-07

    Polarization engineered interband tunnel junctions (TJs) are integrated in nanowire ultraviolet (UV) light emitting diodes (LEDs). A ∼6 V reduction in turn-on voltage is achieved by the integration of tunnel junction at the base of polarization doped nanowire UV LEDs. Moreover, efficient hole injection into the nanowire LEDs leads to suppressed efficiency droop in TJ integrated nanowire LEDs. The combination of both reduced bias voltage and increased hole injection increases the wall plug efficiency in these devices. More than 100 μW of UV emission at ∼310 nm is measured with external quantum efficiency in the range of 4–6 m%. The realization of tunnel junction within the nanowire LEDs opens a pathway towards the monolithic integration of cascaded multi-junction nanowire LEDs on silicon.

  6. Stability and tunneling dynamics of a dark-bright soliton pair...

    Office of Scientific and Technical Information (OSTI)

    Stability and tunneling dynamics of a dark-bright soliton pair in a harmonic trap Title: Stability and tunneling dynamics of a dark-bright soliton pair in a harmonic trap In this ...

  7. Rainier Mesa Sub-CAU Model for N-Tunnel (Conference) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    Conference: Rainier Mesa Sub-CAU Model for N-Tunnel Citation Details In-Document Search Title: Rainier Mesa Sub-CAU Model for N-Tunnel You are accessing a document from the...

  8. Josephson tunnel junctions with chemically vapor deposited polycrystalline germanium barriers

    SciTech Connect (OSTI)

    Kroger, H.; Jillie, D.W.; Smith, L.N.; Phaneuf, L.E.; Potter, C.N.; Shaw, D.M.; Cukauskas, E.J.; Nisenoff, M.

    1984-03-01

    High quality Josephson tunnel junctions have been fabricated whose tunneling barrier is polycrystalline germanium chemically vapor deposited on a NbN base electrode and covered by a Nb counterelectrode. These junctions have excellent characteristics for device applications: values of V/sub m/ (the product of the critical current and the subgap resistance measured at 2 mV and 4.2 K) ranging between 35--48 mV, ideal threshold curves, a steep current rise at the gap voltage, and Josephson current densities from 100 to 1100 A/cm/sup 2/.

  9. Nuclear reactor containment structure with continuous ring tunnel at grade

    DOE Patents [OSTI]

    Seidensticker, Ralph W.; Knawa, Robert L.; Cerutti, Bernard C.; Snyder, Charles R.; Husen, William C.; Coyer, Robert G.

    1977-01-01

    A nuclear reactor containment structure which includes a reinforced concrete shell, a hemispherical top dome, a steel liner, and a reinforced-concrete base slab supporting the concrete shell is constructed with a substantial proportion thereof below grade in an excavation made in solid rock with the concrete poured in contact with the rock and also includes a continuous, hollow, reinforced-concrete ring tunnel surrounding the concrete shell with its top at grade level, with one wall integral with the reinforced concrete shell, and with at least the base of the ring tunnel poured in contact with the rock.

  10. Engineering ferroelectric tunnel junctions through potential profile shaping

    SciTech Connect (OSTI)

    Boyn, S.; Garcia, V. Fusil, S.; Carrtro, C.; Garcia, K.; Collin, S.; Deranlot, C.; Bibes, M.; Barthlmy, A.

    2015-06-01

    We explore the influence of the top electrode materials (W, Co, Ni, Ir) on the electronic band profile in ferroelectric tunnel junctions based on super-tetragonal BiFeO{sub 3}. Large variations of the transport properties are observed at room temperature. In particular, the analysis of current vs. voltage curves by a direct tunneling model indicates that the metal/ferroelectric interfacial barrier height increases with the top-electrode work function. While larger metal work functions result in larger OFF/ON ratios, they also produce a large internal electric field which results in large and potentially destructive switching voltages.

  11. Environmental permit tracking and compliance: Central Artery/Tunnel Project, Boston, MA

    SciTech Connect (OSTI)

    Forbush, L. )

    1993-01-01

    The Central Artery/Tunnel (CA/T) Project in Boston, Massachusetts involves the replacement of the existing I-93 interstate highway (Central Artery) and the extension of I-90 (Massachusetts Turnpike) to Logan International Airport. To date, approximately 95 environmental and related permits have been obtained for the CA/T Project. At least 200 permits from federal, state and local regulatory agencies will be acquired for the entire Project. The proposed action includes construction activities and permanent structures related to the crossing of three bodies of water: Charles River, Fort Point Channel, and Boston Inner Harbor. The Project also includes work in Massachusetts filled tidelands, relocation or construction of outfalls, disposition of construction dewatering and tunnel drainage fluids, and capping of an abandoned landfill. The number of permits, interrelationships between permits and interfaces with design and construction schedules have necessitated the development and implementation of a permit tracking system. The system tracks permit applications from preparation through public and agency review to permit issuance. The issues are discussed in detail: Phased development of the tracking system; Utilization of Project standard scheduling system software, Primavera Project Planner; How the information generated by the tracking system is used at the Project; Report format and production; Construction phase services and the multidiscipline, integrated Project schedule.

  12. Tunnel junction multiple wavelength light-emitting diodes

    DOE Patents [OSTI]

    Olson, Jerry M.; Kurtz, Sarah R.

    1992-01-01

    A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect.

  13. Tunneling control using classical non-linear oscillator

    SciTech Connect (OSTI)

    Kar, Susmita; Bhattacharyya, S. P.

    2014-04-24

    A quantum particle is placed in symmetric double well potential which is coupled to a classical non-linear oscillator via a coupling function. With different spatial symmetry of the coupling and under various controlling fashions, the tunneling of the quantum particle can be enhanced or suppressed, or totally destroyed.

  14. The first tunnel section of the Superconducting Super Collider project

    SciTech Connect (OSTI)

    Lundin, T.K.; Laughton, C.; Nelson, P.P.

    1990-11-01

    The Superconducting Super Collider (SSC) project will be constructed for the United States Department of Energy at a competitively-selected site in Ellis County, Texas, about 30 mile (50 km) south of the central business district of Dallas. The injector system and main collider ring will be housed in 70 mile (110 km) of tunnel, and the project will include additional shafts and underground enclosures with clear spans up to 30 ft (10 m) at depths of more than 250 ft (75 m). The first tunnel segment to be designed and constructed will include approximately 5.9 mile (9.4 km) of 12 ft (3.7 m) finished internal diameter tunnel, four shafts up to 55 ft (16.8 m) diameter, and various connecting tunnels and adits. Construction will be in weak rock lithologies, including mudstones, marls, and chalks with compressive strengths typically between 300 and 2500 psi (2.0 and 17.2 MPa). Design is underway, with an expected bid date before the end of 1990, and with start of construction following in the spring of 1991. 7 refs., 8 figs., 1 tab.

  15. Tunnel junction multiple wavelength light-emitting diodes

    DOE Patents [OSTI]

    Olson, J.M.; Kurtz, S.R.

    1992-11-24

    A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect. 5 figs.

  16. Type B Accident Investigation Board Report on the August 5, 1998, Load Haul Dump Accident at U16b Tunnel, Nevada Test Site

    Broader source: Energy.gov [DOE]

    Thisis theType B Accident Investigation Board report of an industrial accident at the Nevada Test site (NTS), U16b tunnel in which a Bechtel Nevada (BN) employee suffered a compressed skull fracture as a result of being struck onthe head by a valve and fitting assembly on the end of a hose whichhad been broken from a water pipe by a moving piece of construction equipment.

  17. A Model for the Behavior of Magnetic Tunnel Junctions

    SciTech Connect (OSTI)

    Bryan John Baker

    2003-08-05

    A magnetic tunnel junction is a device that changes its electrical resistance with a change in an applied magnetic field. A typical junction consists of two magnetic electrodes separated by a nonmagnetic insulating layer. The magnetizations of the two electrodes can have two possible extreme configurations, parallel and antiparallel. The antiparallel configuration is observed to have the higher measured resistance and the parallel configuration has the lower resistance. To switch between these two configurations a magnetic field is applied to the device which is primarily used to change the orientation of the magnetization of one electrode usually called the free layer, although with sufficient high magnetic field the orientation of the magnetizations of both of the electrodes can be changed. The most commonly used models for describing and explaining the electronic behavior of tunnel junctions are the Simmons model and the Brinkman model. However, both of these models were designed for simple, spin independent tunneling. The Simmons model does not address the issue of applied magnetic fields nor does it address the form of the electronic band structure in the metallic electrodes, including the important factor of spin polarization. The Brinkman model is similar, the main difference between the two models being the shape of the tunneling barrier potential between the two electrodes. Therefore, the research conducted in this thesis has developed a new theoretical model that addresses these important issues starting from basic principles. The main features of the new model include: the development of equations for true spin dependent tunneling through the insulating barrier, the differences in the orientations of the electrode magnetizations on either side of the barrier, and the effects of the density of states function on the behavior of the junction. The present work has explored densities of states that are more realistic than the simplified free electron density

  18. Low-Frequency Electromagnetic Backscatter from Buried Tunnels

    SciTech Connect (OSTI)

    Casey, K; Pao, H

    2006-06-21

    This progress report is submitted under a contract between the Special Project Office of DARPA and Lawrence Livermore National Laboratory. The Project Manager at DARPA is Dr. Michael Zatman. Our purpose under this contract is to investigate interactions between electromagnetic waves and a class of buried targets located in multilayered media with rough interfaces. In this report, we investigate three preliminary problems. In each case our specific goal is to understand various aspects of the electromagnetic wave interaction mechanisms with targets in layered media. The first problem, discussed in Section 2, is that of low-frequency electromagnetic backscattering from a tunnel that is cut into a lossy dielectric half-space. In this problem, the interface between the upper (free space) region and the lower (ground) region is smooth. The tunnel is assumed to be a cylindrical free-space region of infinite extent in its axial direction and with a diameter that is small in comparison to the free-space wavelength. Because its diameter is small, the tunnel can be modeled as a buried ''wire'' described by an equivalent impedance per unit length. In Section 3 we extend the analysis to include a statistically rough interface between the air and ground regions. The interface is modeled as a random-phase screen. Such a screen reduces the coherent power in a plane wave that is transmitted through it, scattering some of the total power into an incoherent field. Our analysis of this second problem quantifies the reduction in the coherent power backscattered from the buried tunnel that is caused by the roughness of the air-ground interface. The problem of low-frequency electromagnetic backscattering from two buried tunnels, parallel to each other but at different locations in the ground, is considered in Section 4. In this analysis, we wish to determine the conditions under which the presence of more than one tunnel can be detected via backscattering. Section 5 concludes the report

  19. Tunnel and Subsurface Void Detection and Range to Target Measurement

    SciTech Connect (OSTI)

    Phillip B. West

    2009-06-01

    Engineers and technicians at the Idaho National Laboratory invented, designed, built and tested a device capable of detecting and measuring the distance to, an underground void, or tunnel. Preliminary tests demonstrated positive detection of, and range to, a void thru as much as 30 meters of top-soil earth. Device uses acoustic driving point impedance principles pioneered by the Laboratory for well-bore physical properties logging. Data receipts recorded by the device indicates constructive-destructive interference patterns characteristic of acoustic wave reflection from a downward step-change in impedance mismatch. Prototype tests demonstrated that interference patterns in receipt waves could depict the patterns indicative of specific distances. A tool with this capability can quickly (in seconds) indicate the presence and depth/distance of a void or tunnel. Using such a device, border security and military personnel can identify threats of intrusion or weapons caches in most all soil conditions including moist and rocky.

  20. Mission Support - Hanford Site

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

    Infrastructure & Support The Infrastructure & Support Division oversees water, sewer, electrical power, roads, fleet, motor carrier, crane and rigging, maintenance services, ...

  1. Scanning Tunneling Microscope Data Acquistion and Control System

    Energy Science and Technology Software Center (OSTI)

    1995-02-01

    SHOESCAN is a PC based code that acquires and displays data for Scanning Tunneling Microscopes (STM). SHOESCAN interfaces with the STM through external electronic feedback and raster control circuits that are controlled by I/O boards on the PC bus. Data is displayed on a separate color monitor that is interfaced to the PC through an additional frame-grabber board. SHOESCAN can acquire a wide range of surface topographic information as well as surface electronic structure information.

  2. Stationary bubbles and their tunneling channels toward trivial geometry

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

    Chen, Pisin; Domènech, Guillem; Sasaki, Misao; Yeom, Dong-han

    2016-04-07

    In the path integral approach, one has to sum over all histories that start from the same initial condition in order to obtain the final condition as a superposition of histories. Applying this into black hole dynamics, we consider stable and unstable stationary bubbles as a reasonable and regular initial condition. We find examples where the bubble can either form a black hole or tunnel toward a trivial geometry, i.e., with no singularity nor event horizon. We investigate the dynamics and tunneling channels of true vacuum bubbles for various tensions. In particular, in line with the idea of superposition ofmore » geometries, we build a classically stable stationary thin-shell solution in a Minkowski background where its fate is probabilistically given by non-perturbative effects. Since there exists a tunneling channel toward a trivial geometry in the entire path integral, the entire information is encoded in the wave function. This demonstrates that the unitarity is preserved and there is no loss of information when viewed from the entire wave function of the universe, whereas a semi-classical observer, who can see only a definitive geometry, would find an effective loss of information. Ultimately, this may provide a resolution to the information loss dilemma.« less

  3. A 233 km tunnel for lepton and hadron colliders

    SciTech Connect (OSTI)

    Summers, D. J.; Cremaldi, L. M.; Datta, A.; Duraisamy, M.; Luo, T.; Lyons, G. T.

    2012-12-21

    A decade ago, a cost analysis was conducted to bore a 233 km circumference Very Large Hadron Collider (VLHC) tunnel passing through Fermilab. Here we outline implementations of e{sup +}e{sup -}, pp-bar , and {mu}{sup +}{mu}{sup -} collider rings in this tunnel using recent technological innovations. The 240 and 500 GeV e{sup +}e{sup -} colliders employ Crab Waist Crossings, ultra low emittance damped bunches, short vertical IP focal lengths, superconducting RF, and low coercivity, grain oriented silicon steel/concrete dipoles. Some details are also provided for a high luminosity 240 GeV e{sup +}e{sup -} collider and 1.75 TeV muon accelerator in a Fermilab site filler tunnel. The 40 TeV pp-bar collider uses the high intensity Fermilab p-bar source, exploits high cross sections for pp-bar production of high mass states, and uses 2 Tesla ultra low carbon steel/YBCO superconducting magnets run with liquid neon. The 35 TeV muon ring ramps the 2 Tesla superconducting magnets at 9 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 1.75 to 17.5 TeV in 63 orbits with 71% survival, and mitigates neutrino radiation with phase shifting, roller coaster motion in a FODO lattice.

  4. Analysis of different tunneling mechanisms of In{sub x}Ga{sub 1?x}As/AlGaAs tunnel junction light-emitting transistors

    SciTech Connect (OSTI)

    Wu, Cheng-Han; Wu, Chao-Hsin

    2014-10-27

    The electrical and optical characteristics of tunnel junction light-emitting transistors (TJLETs) with different indium mole fractions (x?=?5% and 2.5%) of the In{sub x}Ga{sub 1?x}As base-collector tunnel junctions have been investigated. Two electron tunneling mechanisms (photon-assisted or direct tunneling) provide additional currents to electrical output and resupply holes back to the base region, resulting in the upward slope of I-V curves and enhanced optical output under forward-active operation. The larger direct tunneling probability and stronger Franz-Keldysh absorption for 5% TJLET lead to higher collector current slope and less optical intensity enhancement when base-collector junction is under reverse-biased.

  5. Developing, Staffing, and Overseeing a State Energy Savings Performance Contracting Program

    Broader source: Energy.gov [DOE]

    U.S. Department of Energy (DOE) Technical Assistance Program (TAP) webinar held on March 26, 2013, dealing with energy savings performance contracting.

  6. Facility Closure Report for T-Tunnel (U12t), Area 12, Nevada Test Site, Nevada

    SciTech Connect (OSTI)

    NSTec Environmental Restoration

    2008-08-01

    This Facility Closure Report (FCR) has been prepared to document the actions taken to permanently close the remaining accessible areas of U12t-Tunnel (T-Tunnel) in Area 12 of the Nevada Test Site (NTS). The closure of T-Tunnel was a prerequisite to transfer facility ownership from the Defense Threat Reduction Agency (DTRA) to the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO). Closure of the facility was accomplished with the cooperation and concurrence of both NNSA/NSO and the Nevada Division of Environmental Protection (NDEP). The purpose of this FCR is to document that the closure of T-Tunnel complied with the closure requirements specified in the Facility Closure Plan for N- and T-Tunnels Area 12, Nevada Test Site (Appendix D) and that the facility is ready for transfer to NNSA/NSO. The Facility Closure Plan (FCP) is provided in Appendix D. T-Tunnel is located approximately 42 miles north of Mercury in Area 12 of the NTS (Figure 1). Between 1970 and 1987, T-Tunnel was used for six Nuclear Weapons Effects Tests (NWETs). The tunnel was excavated horizontally into the volcanic tuffs of Rainier Mesa. The T-Tunnel complex consists of a main access drift with two NWET containment structures, a Gas Seal Plug (GSP), and a Gas Seal Door (GSD) (Figure 2). The T-Tunnel complex was mothballed in 1993 to preserve the tunnel for resumption of testing, should it happen in the future, to stop the discharge of tunnel effluent, and to prevent unauthorized access. This was accomplished by sealing the main drift GSD.

  7. Baker-Barry Tunnel Lighting: Evaluation of a Potential GATEWAY Demonstrations Project

    SciTech Connect (OSTI)

    Tuenge, Jason R.

    2011-06-01

    The U.S. Department of Energy (DOE) is evaluating the Baker-Barry Tunnel as a potential GATEWAY Demonstrations project for deployment of solid-state lighting (SSL) technology. The National Park Service (NPS) views this project as a possible proving ground and template for implementation of light-emitting diode (LED) luminaires in other NPS tunnels, thereby expanding the estimated 40% energy savings from 132 MWh/yr for this tunnel to a much larger figure national

  8. DOE/NV/26383-109 A Historical Evaluation of the U12t Tunnel,

    National Nuclear Security Administration (NNSA)

    A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada Prepared ... Defense Threat Reduction Agency Nevada Test Site Office, Mercury, Nevada Colleen M. ...

  9. Valley filter from magneto-tunneling between single and bi-layer graphene

    SciTech Connect (OSTI)

    Pratley, L.; Zülicke, U.

    2014-02-24

    We consider tunneling transport between two parallel graphene sheets; where one is a single-layer sample and the other one a bi-layer. In the presence of an in-plane magnetic field, the interplay between combined energy and momentum conservation in a tunneling event and the distinctive chiral nature of charge carriers in the two systems turns out to favor tunneling of electrons from one of the two valleys in the graphene Brillouin zone. Adjusting the field strength enables manipulation of the valley polarization of the current, which reaches its maximum value of 100% concomitantly with a maximum of the tunneling conductance.

  10. Spin-symmetry conversion in methyl rotors induced by tunnel resonance at low temperature

    SciTech Connect (OSTI)

    Zhang, B.; Sun, C.; Horsewill, A. J.; Alsanoosi, A. M.; Aibout, A.

    2014-02-28

    Field-cycling NMR in the solid state at low temperature (4.2 K) has been employed to measure the tunneling spectra of methyl (CH{sub 3}) rotors in phenylacetone and toluene. The phenomenon of tunnel resonance reveals anomalies in {sup 1}H magnetization from which the following tunnel frequencies have been determined: phenylacetone, ν{sub t} = 6.58 ± 0.08 MHz; toluene, ν{sub t(1)} = 6.45 ± 0.06 GHz and ν{sub t(2)} = 7.07 ± 0.06 GHz. The tunnel frequencies in the two samples differ by three orders of magnitude, meaning different experimental approaches are required. In phenylacetone the magnetization anomalies are observed when the tunnel frequency matches one or two times the {sup 1}H Larmor frequency. In toluene, doping with free radicals enables magnetization anomalies to be observed when the tunnel frequency is equal to the electron spin Larmor frequency. Cross-polarization processes between the tunneling and Zeeman systems are proposed and form the basis of a thermodynamic model to simulate the tunnel resonance spectra. These invoke space-spin interactions to drive the changes in nuclear spin-symmetry. The tunnel resonance lineshapes are explained, showing good quantitative agreement between experiment and simulations.

  11. Collegiate Wind Competition Turbines go Blade-to-Blade in Wind Tunnel Tests

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

    at WINDPOWER | Department of Energy Turbines go Blade-to-Blade in Wind Tunnel Tests at WINDPOWER Collegiate Wind Competition Turbines go Blade-to-Blade in Wind Tunnel Tests at WINDPOWER March 28, 2014 - 5:11pm Addthis This wind tunnel constructed by NREL engineers will test the small wind turbines designed by 10 university teams competing in DOE's Collegiate Wind Competition. This wind tunnel constructed by NREL engineers will test the small wind turbines designed by 10 university teams

  12. Hydroelectric power: Technology and planning. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect (OSTI)

    Not Available

    1993-08-01

    The bibliography contains citations concerning hydroelectric power technology and planning. Reservoir, dam, water tunnel, and hydraulic gate design, construction, and operation are discussed. Water supply, flood control, irrigation programs, and environmental effects of hydroelectric power plants are presented. Mathematical modeling and simulation analysis are also discussed. (Contains 250 citations and includes a subject term index and title list.)

  13. Hydroelectric power: Technology and planning. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect (OSTI)

    Not Available

    1994-05-01

    The bibliography contains citations concerning hydroelectric power technology and planning. Reservoir, dam, water tunnel, and hydraulic gate design, construction, and operation are discussed. Water supply, flood control, irrigation programs, and environmental effects of hydroelectric power plants are presented. Mathematical modeling and simulation analysis are also discussed. (Contains 250 citations and includes a subject term index and title list.)

  14. Structure factors for tunneling ionization rates of diatomic molecules

    SciTech Connect (OSTI)

    Saito, Ryoichi; Tolstikhin, Oleg I.; Madsen, Lars Bojer; Morishita, Toru

    2015-05-15

    Within the leading-order, single-active-electron, and frozen-nuclei approximation of the weak-field asymptotic theory, the rate of tunneling ionization of a molecule in an external static uniform electric field is determined by the structure factor for the highest occupied molecular orbital. We present the results of systematic calculations of structure factors for 40 homonuclear and heteronuclear diatomic molecules by the Hartree–Fock method using a numerical grid-based approach implemented in the program X2DHF.

  15. Ramp-edge structured tunneling devices using ferromagnet electrodes

    DOE Patents [OSTI]

    Kwon, Chuhee; Jia, Quanxi

    2002-09-03

    The fabrication of ferromagnet-insulator-ferromagnet magnetic tunneling junction devices using a ramp-edge geometry based on, e.g., (La.sub.0.7 Sr.sub.0.3) MnO.sub.3, ferromagnetic electrodes and a SrTiO.sub.3 insulator is disclosed. The maximum junction magnetoresistance (JMR) as large as 23% was observed below 300 Oe at low temperatures (T<100 K). These ramp-edge junctions exhibited JMR of 6% at 200 K with a field less than 100 Oe.

  16. Observation of diamond turned OFHC copper using Scanning Tunneling Microscopy

    SciTech Connect (OSTI)

    Grigg, D.A.; Russell, P.E.; Dow, T.A.

    1988-12-01

    Diamond turned OFHC copper samples have been observed within the past few months using the Scanning Tunneling Microscope. Initial results have shown evidence of artifacts which may be used to better understand the diamond turning process. The STM`s high resolution capability and three dimensional data representation allows observation and study of surface features unobtainable with conventional profilometry systems. Also, the STM offers a better quantitative means by which to analyze surface structures than the SEM. This paper discusses findings on several diamond turned OFHC copper samples having different cutting conditions. Each sample has been cross referenced using STM and SEM.

  17. Selective niobium anodization process for fabricating Josephson tunnel junctions

    SciTech Connect (OSTI)

    Kroger, H.; Smith, L.N.; Jillie, D.W.

    1981-08-01

    A novel process for fabricating refractory sperconducting tunnel junctions is described, which is useful with both deposited and native oxide barriers. The distinguishing feature of the method is that the entire superconductor-barrier-superconductor sandwich is formed before the patterning of any layer. Isolated Josephson junctions are then formed by anodizing through the upper electrode, while the devices themselves are protected by a photoresist mask. Using this process, Nb-Si:H-Nb junctions have been fabricated, whose product of critical current and subgap resistance exceeds 10 mV and whose critical current density varies by about 50% over a 2-in. diameter wafer.

  18. Nonlinearity-induced destruction of resonant tunneling in the Wannier-Stark problem

    SciTech Connect (OSTI)

    Wimberger, S.; Mannella, R.; Morsch, O.; Arimondo, E.; Kolovsky, A. R.; Buchleitner, A.

    2005-12-15

    We present detailed numerical results on the dynamics of a Bose-Einstein condensate in a tilted periodic optical lattice over many Bloch periods. We show that an increasing atom-atom interaction systematically affects coherent tunneling, and eventually destroys the resonant tunneling peaks.

  19. Water Quality

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

    Water Quality Water Quality We protect water quality through stormwater control measures and an extensive network of monitoring wells and stations encompassing groundwater, surface...

  20. Water Quality

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

    Water Quality Water Quality We protect water quality through stormwater control measures and an extensive network of monitoring wells and stations encompassing groundwater, surface ...

  1. Facility Closure Report for Tunnel U16a, Area 16, Nevada Test Site, Nevada

    SciTech Connect (OSTI)

    NSTec Environmental Restoration

    2009-07-01

    U16a is not listed in the Federal Facility Agreement and Consent Order. The closure of U16a was sponsored by the Defense Threat Reduction Agency (DTRA) and performed with the cooperation of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the Nevada Division of Environmental Protection. This report documents closure of this site as identified in the DTRA Fiscal Year 2008 Statement of Work, Task 6.3. Closure activities included: Removing and disposing of a shack and its contents Disposing of debris from within the shack and in the vicinity of the tunnel entrance Verifying that the tunnel is empty Welding screened covers over tunnel vent holes to limit access and allow ventilation Constructing a full-tunnel cross-section fibercrete bulkhead to prevent access to the tunnel Field activities were conducted from July to August 2008.

  2. Combined Experiment Phase 1. [Horizontal axis wind turbines: wind tunnel testing versus field testing

    SciTech Connect (OSTI)

    Butterfield, C.P.; Musial, W.P.; Simms, D.A.

    1992-10-01

    How does wind tunnel airfoil data differ from the airfoil performance on an operating horizontal axis wind turbine (HAWT) The National Renewable Energy laboratory has been conducting a comprehensive test program focused on answering this question and understanding the basic fluid mechanics of rotating HAWT stall aerodynamics. The basic approach was to instrument a wind rotor, using an airfoil that was well documented by wind tunnel tests, and measure operating pressure distributions on the rotating blade. Based an the integrated values of the pressure data, airfoil performance coefficients were obtained, and comparisons were made between the rotating data and the wind tunnel data. Care was taken to the aerodynamic and geometric differences between the rotating and the wind tunnel models. This is the first of two reports describing the Combined Experiment Program and its results. This Phase I report covers background information such as test setup and instrumentation. It also includes wind tunnel test results and roughness testing.

  3. Tunneling magnetoresistance in Fe{sub 3}Si/MgO/Fe{sub 3}Si(001) magnetic tunnel junctions

    SciTech Connect (OSTI)

    Tao, L. L.; Liang, S. H.; Liu, D. P.; Wei, H. X.; Han, X. F.; Wang, Jian

    2014-04-28

    We present a theoretical study of the tunneling magnetoresistance (TMR) and spin-polarized transport in Fe{sub 3}Si/MgO/Fe{sub 3}Si(001) magnetic tunnel junction (MTJ). It is found that the spin-polarized conductance and bias-dependent TMR ratios are rather sensitive to the structure of Fe{sub 3}Si electrode. From the symmetry analysis of the band structures, we found that there is no spin-polarized Δ{sub 1} symmetry bands crossing the Fermi level for the cubic Fe{sub 3}Si. In contrast, the tetragonal Fe{sub 3}Si driven by in-plane strain reveals half-metal nature in terms of Δ{sub 1} state. The giant TMR ratios are predicted for both MTJs with cubic and tetragonal Fe{sub 3}Si electrodes under zero bias. However, the giant TMR ratio resulting from interface resonant transmission for the former decreases rapidly with the bias. For the latter, the giant TMR ratio can maintain up to larger bias due to coherent transmission through the majority-spin Δ{sub 1} channel.

  4. Insensitivity of tunneling anisotropic magnetoresistance to non-magnetic electrodes

    SciTech Connect (OSTI)

    Wang, Y. Y.; Song, C. Wang, G. Y.; Zeng, F.; Pan, F.

    2013-11-11

    Ferromagnetic electrodes play a crucial role in magnetoresistance effect and spin injection, whereas the essential features of non-magnetic metal electrodes in spintronics are commonly ignored except for their electrical conductivity. Here, we verify that the room-temperature tunneling anisotropic magnetoresistance (TAMR) behavior in antiferromagnet-based [Pt/Co]/IrMn/AlO{sub x}/metal (metal = Pt, Au, Cu, Al) junctions is insensitive to the top metal electrodes. Similar out-of-plane signals are detected for different electrodes, in contrast to the varied shapes of in-plane TAMR curves which are most likely attributed to the differences in the multidomain structure of the magnetic electrode. This would add a different dimension to spintronics.

  5. Theory of multiphoton and tunnel ionization in a bichromatic field

    SciTech Connect (OSTI)

    Bagulov, D. S.; Kotelnikov, I. A.

    2013-01-15

    The imaginary-time method [6, 7] is used to calculate the multiphoton and tunnel ionization probabilities for atoms in a laser radiation field part of which is converted into the second harmonic. We assume that the first harmonic has a linear or elliptical polarization and the second harmonic is polarized linearly, with its polarization vector making an arbitrary angle with that of the first harmonic. The mean momentum of the photoelectrons knocked out from atoms is shown to depend on the phase shift between the first and second harmonics and their mutual polarization and to be identically equal to zero for a monochromatic field. An important difference between the case of elliptical polarization and the case of linear polarization of both harmonics is the absence of conditions under which the conditions for dominance of one of the two generation mechanisms considered here can be identified during the generation of terahertz radiation from the region of optical breakdown in a gas.

  6. High energy storage capacitor by embedding tunneling nano-structures

    DOE Patents [OSTI]

    Holme, Timothy P; Prinz, Friedrich B; Van Stockum, Philip B

    2014-11-04

    In an All-Electron Battery (AEB), inclusions embedded in an active region between two electrodes of a capacitor provide enhanced energy storage. Electrons can tunnel to/from and/or between the inclusions, thereby increasing the charge storage density relative to a conventional capacitor. One or more barrier layers is present in an AEB to block DC current flow through the device. The AEB effect can be enhanced by using multi-layer active regions having inclusion layers with the inclusions separated by spacer layers that don't have the inclusions. The use of cylindrical geometry or wrap around electrodes and/or barrier layers in a planar geometry can enhance the basic AEB effect. Other physical effects that can be employed in connection with the AEB effect are excited state energy storage, and formation of a Bose-Einstein condensate (BEC).

  7. Ferroelectric modulation on resonant tunneling through perovskite double-barriers

    SciTech Connect (OSTI)

    Du, Ruifang; Qiu, Xiangbiao; Li, Aidong; Wu, Di

    2014-04-07

    The negative differential resistance (NDR) due to resonance tunneling is achieved at room temperature in perovskite double-barrier heterostructures composed of a 10 unit-cell-thick SrTiO{sub 3} quantum well sandwiched in two 10 unit-cell-thick LaAlO{sub 3} barriers. The NDR occurs at 1.2?V and does not change with voltage cycling. When the paraelectric SrTiO{sub 3} quantum well is replaced by a ferroelectric BaTiO{sub 3}, the onset of the NDR can be modulated by polarization switching in the ultrathin BaTiO{sub 3}. A polarization pointing to the collector lowers the NDR voltage but a polarization pointing to the emitter increases it. The shift of the NDR voltage is ascribed to reversal of the extra electric field in the quantum well due to the polarization switching.

  8. Single-charge detection by an atomic precision tunnel junction

    SciTech Connect (OSTI)

    House, M. G. Peretz, E.; Keizer, J. G.; Hile, S. J.; Simmons, M. Y.

    2014-03-17

    We demonstrate sensitive detection of single charges using a planar tunnel junction 8.5?nm wide and 17.2?nm long defined by an atomically precise phosphorus doping profile in silicon. The conductance of the junction responds to a nearby gate potential and also to changes in the charge state of a quantum dot patterned 52?nm away. The response of this detector is monotonic across the entire working voltage range of the device, which will make it particularly useful for studying systems of multiple quantum dots. The charge sensitivity is maximized when the junction is most conductive, suggesting that more sensitive detection can be achieved by shortening the length of the junction to increase its conductance.

  9. Cavity-enhanced resonant tunneling photodetector at telecommunication wavelengths

    SciTech Connect (OSTI)

    Pfenning, Andreas Hartmann, Fabian; Langer, Fabian; Hfling, Sven; Kamp, Martin; Worschech, Lukas

    2014-03-10

    An AlGaAs/GaAs double barrier resonant tunneling diode (RTD) with a nearby lattice-matched GaInNAs absorption layer was integrated into an optical cavity consisting of five and seven GaAs/AlAs layers to demonstrate cavity enhanced photodetection at the telecommunication wavelength 1.3??m. The samples were grown by molecular beam epitaxy and RTD-mesas with ring-shaped contacts were fabricated. Electrical and optical properties were investigated at room temperature. The detector shows maximum photocurrent for the optical resonance at a wavelength of 1.29??m. At resonance a high sensitivity of 3.110{sup 4} A/W and a response up to several pA per photon at room temperature were found.

  10. AlGaAs/InGaAlP tunnel junctions for multijunction solar cells

    SciTech Connect (OSTI)

    SHARPS,P.R.; LI,N.Y.; HILLS,J.S.; HOU,H.; CHANG,PING-CHIH; BACA,ALBERT G.

    2000-05-16

    Optimization of GaInP{sub 2}/GaAs dual and GaInP{sub 2}/GaAs/Ge triple junction cells, and development of future generation monolithic multi-junction cells will involve the development of suitable high bandgap tunnel junctions. There are three criteria that a tunnel junction must meet. First, the resistance of the junction must be kept low enough so that the series resistance of the overall device is not increased. For AMO, 1 sun operation, the tunnel junction resistance should be below 5 x 10{sup {minus}2} {Omega}-cm. Secondly, the peak current density for the tunnel junction must also be larger than the J{sub sc} of the cell so that the tunnel junction I-V curve does not have a deleterious effect on the I-V curve of the multi-junction device. Finally, the tunnel junction must be optically transparent, i.e., there must be a minimum of optical absorption of photons that will be collected by the underlying subcells. The paper reports the investigation of four high bandgap tunnel junctions grown by metal-organic chemical vapor deposition.

  11. Radioactive air emissions notice of construction for deactivation of the PUREX storage tunnel number 2

    SciTech Connect (OSTI)

    JOHNSON, R.E.

    1999-10-11

    The Plutonium-Uranium Extraction (PUREX) Plant Storage Tunnel Number 2 (hereafter referred to as the PUREX Tunnel) was built in 1964. Since that time, the PUREX Tunnel has been used for storage of radioactive and mixed waste. In 1991, the PUREX Plant ceased operations and was transitioned to deactivation. The PUREX Tunnel continued to receive PUREX Plant waste material for storage during transition activities. Before 1995, a decision was made to store radioactive and mixed waste in the PUREX Tunnel generated from other onsite sources, on a case-by-case basis. This notice of construction (NOC) describes the activities associated with the reactivation of the PUREX Tunnel ventilation system and the transfer of up to 3.5 million curies (MCi) of radioactive waste to the PUREX Tunnel from any location on the Hanford Site. The unabated total effective dose equivalent (TEDE) estimated for the hypothetical offsite maximally exposed individual (MEI) is 5.6 E-2 millirem (mrem). The abated TEDE conservatively is estimated to account for 1.9 E-5 mrem to the MEI. The following text provides information requirements of Appendix A of Washington Administrative Code (WAC) 246-247 (requirements 1 through 18).

  12. Physical properties and analytical models of band-to-band tunneling in low-bandgap semiconductors

    SciTech Connect (OSTI)

    Shih, Chun-Hsing Dang Chien, Nguyen

    2014-01-28

    Low-bandgap semiconductors, such as InAs and InSb, are widely considered to be ideal for use in tunnel field-effect transistors to ensure sufficient on-current boosting at low voltages. This work elucidates the physical and mathematical considerations of applying conventional band-to-band tunneling models in low-bandgap semiconductors, and presents a new analytical alternative for practical use. The high-bandgap tunneling generates most at maximum field region with shortest tunnel path, whereas the low-bandgap generations occur dispersedly because of narrow tunnel barrier. The local electrical field associated with tunneling-electron numbers dominates in low-bandgap materials. This work proposes decoupled electric-field terms in the pre-exponential factor and exponential function of generation-rate expressions. Without fitting, the analytical results and approximated forms exhibit great agreements with the sophisticated forms both in high- and low-bandgap semiconductors. Neither nonlocal nor local field is appropriate to be used in numerical simulations for predicting the tunneling generations in a variety of low- and high-bandgap semiconductors.

  13. The importance of Fe surface states for spintronic devices based on magnetic tunnel junctions

    SciTech Connect (OSTI)

    Chantis, Athanasios N

    2008-01-01

    In this article we give a review of our recent theoretical studies of the influence of Fe(001) surface (interface) states on spin-polarized electron transport across magnetic tunnel junctions with Fe electrodes. We show that minority-spin surface (interface) states are responsible for at least two effects which are important for spin electronics. First, they can produce a sizable tunneling anisotropic magnetoresistance in magnetic tunnel junctions with a single Fe electrode. The effect is driven by a Rashba shift of the resonant surface band when the magnetization changes direction. This can introduce a new class of spintronic devices, namely, tunneling magnetoresistance junctions with a single ferromagnetic electrode. Second, in Fe/GaAs(001) magnetic tunnel junctions minority-spin interface states produce a strong dependence of the tunneling current spin polarization on applied electrical bias. A dramatic sign reversal within a voltage range of just a few tenths of an eV is predicted. This explains the observed sign reversal of spin polarization in recent experiments of electrical spin injection in Fe/GaAs(001) and related reversal of tunneling magnetoresistance through vertical Fe/GaAs/Fe trilayers.

  14. Characterization of aluminum oxide tunnel barriers by combining transport measurements and transmission electron microscopy imaging

    SciTech Connect (OSTI)

    Aref, T.; Averin, A.; Nguyend, H. Q.; Pekola, J. P.; Dijken, S. van; Yao, L. D.; Ferring, A.; Koberidze, M.; Nieminen, R. M.

    2014-08-21

    We present two approaches for studying the uniformity of a tunnel barrier. The first approach is based on measuring single-electron and two-electron tunneling in a hybrid single-electron transistor. Our measurements indicate that the effective area of a conduction channel is about one order of magnitude larger than predicted by theoretical calculations. With the second method, transmission electron microscopy, we demonstrate that variations in the barrier thickness are a plausible explanation for the larger effective area and an enhancement of higher order tunneling processes.

  15. Electron tunnelling through single azurin molecules can be on/off switched by voltage pulses

    SciTech Connect (OSTI)

    Baldacchini, Chiara; Kumar, Vivek; Bizzarri, Anna Rita; Cannistraro, Salvatore

    2015-05-04

    Redox metalloproteins are emerging as promising candidates for future bio-optoelectronic and nano-biomemory devices, and the control of their electron transfer properties through external signals is still a crucial task. Here, we show that a reversible on/off switching of the electron current tunnelling through a single protein can be achieved in azurin protein molecules adsorbed on gold surfaces, by applying appropriate voltage pulses through a scanning tunnelling microscope tip. The observed changes in the hybrid system tunnelling properties are discussed in terms of long-sustained charging of the protein milieu.

  16. ScanningTunneling Luminescence of Grain Boundaries in Cu(In,Ga)Se2

    SciTech Connect (OSTI)

    Romero, M. J.; Jiang, C.-S.; Al-Jassim, M. M.; Noufi, R.

    2005-01-01

    At the Laboratory, photon emission in semiconductors has been mapped in the nanoscale using scanning tunneling microscopy (STM). In this Solar Program Review Meeting, we report on the latest results obtained in Cu(In,Ga)Se2 (CIGS) thin films by this adapted STM. Scanning tunneling luminescence (STL) spectroscopy suggests that photons are emitted near the surface of CIGS. STL is excited either by (1) diffusion of tunneling electrons and subsequent recombination with available holes in CIGS or (2) impact ionization by hot electrons. Which process becomes predominant depends on the voltage applied to the STM tip. Photon mapping shows electronically active, extended defects near the surface of CIGS thin films.

  17. Water Security

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

    SunShot Grand Challenge: Regional Test Centers Water Security HomeTag:Water Security Electricity use by water service sector and county. Shown are electricity use by (a) ...

  18. Water Power

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

    Stationary PowerEnergy Conversion EfficiencyWater Power Water Power Tara Camacho-Lopez 2016-06-01T22:32:54+00:00 Enabling a successful water power industry. Hydropower ...

  19. Demonstration of forward inter-band tunneling in GaN by polarization engineering

    SciTech Connect (OSTI)

    Krishnamoorthy, Sriram; Park, Pil Sung; Rajan, Siddharth

    2011-12-05

    We report on the design, fabrication, and characterization of GaN interband tunnel junction showing forward tunneling characteristics. We have achieved very high forward tunneling currents (153 mA/cm{sup 2} at 10 mV, and 17.7 A/cm{sup 2} peak current) in polarization-engineered GaN/InGaN/GaN heterojunction diodes grown by plasma assisted molecular beam epitaxy. We also report the observation of repeatable negative differential resistance in interband III-Nitride tunnel junctions, with peak-valley current ratio of 4 at room temperature. The forward current density achieved in this work meets the typical current drive requirements of a multi-junction solar cell.

  20. Probing the thiol-gold planar interface by spin polarized tunneling

    SciTech Connect (OSTI)

    Zhang, Xiaohang; McGill, Stephen A.; Xiong, Peng; Wang, Xiaolei; Zhao, Jianhua

    2014-04-14

    Reports of induced magnetism at thiol-gold interface have generated considerable recent interest. In these studies, the sample magnetization was generally measured by superconducting quantum interference device magnetometry which has limitation in determining surface and interface magnetism. In this work, we have fabricated planar tunnel junctions incorporating a thiol-gold interface. An observed room temperature humidity effect together with low temperature inelastic electron tunneling spectroscopy confirmed the existence of a thiol-gold interface in the organic-inorganic hybrid heterostructure. Spin polarized tunneling measurements were performed to probe the spin polarization at the thiol-gold interface; however, the obtained spin polarized tunneling spectra indicate no measurable spin polarization at the thiol-gold interface.

  1. Band structure effects on resonant tunneling in III-V quantum...

    Office of Scientific and Technical Information (OSTI)

    in III-V quantum wells versus two-dimensional vertical heterostructures Citation Details In-Document Search Title: Band structure effects on resonant tunneling in III-V quantum ...

  2. Fire modeling for Building 221-T - T Plant Canyon Deck and Railroad Tunnel

    SciTech Connect (OSTI)

    Oar, D.L.

    1994-09-29

    This report was prepared by Hughes Associates, Inc. to document the results of fire models for building 221-T Canyon Deck and Railroad Tunnel. Backup data is contained in document No. WHC-SD-CP-ANAL-010, Rev. 0.

  3. Wind Tunnel Tests of Parabolic Trough Solar Collectors: March 2001--August 2003

    SciTech Connect (OSTI)

    Hosoya, N.; Peterka, J. A.; Gee, R. C.; Kearney, D.

    2008-05-01

    Conducted extensive wind-tunnel tests on parabolic trough solar collectors to determine practical wind loads applicable to structural design for stress and deformation, and local component design for concentrator reflectors.

  4. Suppression criteria of parasitic mode oscillations in a gyrotron beam tunnel

    SciTech Connect (OSTI)

    Kumar, Nitin; Singh, Udaybir; Sinha, A. K.; Singh, T. P.

    2011-02-15

    This paper presents the design criteria of the parasitic mode oscillations suppression for a periodic, ceramic, and copper loaded gyrotron beam tunnel. In such a type of beam tunnel, the suppression of parasitic mode oscillations is an important design problem. A method of beam-wave coupling coefficient and its mathematical formulation are presented. The developed design criteria are used in the beam tunnel design of a 42 GHz gyrotron to be developed for the Indian TOKAMAK system. The role of the thickness and the radius of the beam tunnel copper rings to obtain the developed design criteria are also discussed. The commercially available electromagnetic code CST and the electron trajectory code EGUN are used for the simulations.

  5. Resonant tunneling device with two-dimensional quantum well emitter and base layers

    DOE Patents [OSTI]

    Simmons, J.A.; Sherwin, M.E.; Drummond, T.J.; Weckwerth, M.V.

    1998-10-20

    A double electron layer tunneling device is presented. Electrons tunnel from a two dimensional emitter layer to a two dimensional tunneling layer and continue traveling to a collector at a lower voltage. The emitter layer is interrupted by an isolation etch, a depletion gate, or an ion implant to prevent electrons from traveling from the source along the emitter to the drain. The collector is similarly interrupted by a backgate, an isolation etch, or an ion implant. When the device is used as a transistor, a control gate is added to control the allowed energy states of the emitter layer. The tunnel gate may be recessed to change the operating range of the device and allow for integrated complementary devices. Methods of forming the device are also set forth, utilizing epoxy-bond and stop etch (EBASE), pre-growth implantation of the backgate or post-growth implantation. 43 figs.

  6. Resonant tunneling device with two-dimensional quantum well emitter and base layers

    DOE Patents [OSTI]

    Simmons, Jerry A.; Sherwin, Marc E.; Drummond, Timothy J.; Weckwerth, Mark V.

    1998-01-01

    A double electron layer tunneling device is presented. Electrons tunnel from a two dimensional emitter layer to a two dimensional tunneling layer and continue traveling to a collector at a lower voltage. The emitter layer is interrupted by an isolation etch, a depletion gate, or an ion implant to prevent electrons from traveling from the source along the emitter to the drain. The collector is similarly interrupted by a backgate, an isolation etch, or an ion implant. When the device is used as a transistor, a control gate is added to control the allowed energy states of the emitter layer. The tunnel gate may be recessed to change the operating range of the device and allow for integrated complementary devices. Methods of forming the device are also set forth, utilizing epoxy-bond and stop etch (EBASE), pre-growth implantation of the backgate or post-growth implantation.

  7. water scarcity

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

    Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 ... Geochemistry Geoscience SubTER Carbon Sequestration Program Leadership EnergyWater Nexus ...

  8. water savings

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

    Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 ... Geochemistry Geoscience SubTER Carbon Sequestration Program Leadership EnergyWater Nexus ...

  9. water infrastructure

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    Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 ... Geochemistry Geoscience SubTER Carbon Sequestration Program Leadership EnergyWater Nexus ...

  10. Water Demand

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    Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 ... Geochemistry Geoscience SubTER Carbon Sequestration Program Leadership EnergyWater Nexus ...

  11. drinking water

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

    drinking water - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us ... Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 ...

  12. Water Power

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

    Water Power Sandia's 117-scale WEC device with being tested in the maneuvering and ... EC, News, Renewable Energy, Water Power Sandia National Laboratories Uses Its Wave Energy ...

  13. Water Efficiency

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

    5-6, 2014 Cape Canaveral, Florida WATER EFFICIENCY Federal Utility Partnership ...ate.mcmordie@pnnl.gov * Francis Wheeler - Water Savers, LLC * fwheeler@watersaversllc.com ...

  14. Water Power

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

    Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 ... Geochemistry Geoscience SubTER Carbon Sequestration Program Leadership EnergyWater Nexus ...

  15. Water Security

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    Water Security - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us ... Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 ...

  16. Vacuum gaps with small tunnel currents at large electric field and its

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

    potential applications for energy storage, charge storage and power supplies. | Stanford Synchrotron Radiation Lightsource Vacuum gaps with small tunnel currents at large electric field and its potential applications for energy storage, charge storage and power supplies. Friday, May 27, 2011 - 4:00pm SSRL Conference Room 137-226 Alfred Hubler, Department of Physics, University of Illinois, Urbana-Champaign We study tunnel currents and electric break down in vacuum gaps experimentally and

  17. The fluid dynamics of a miniature dilution tunnel for internal-combustion engine aerosol measurement

    SciTech Connect (OSTI)

    Kommer, Eric M.; Puzinauskas, Paulius V.; Buckley, Steven G.

    2007-11-15

    This paper investigates the fluid dynamics of a particular mini-dilution tunnel using LDV, flow visualization, a tracer sample technique and CFD. The mini-dilution tunnel studied had a 3.175 mm inside diameter tube discharging on the centerline of the tunnel where the diameter increases in a single step to 7.62 cm. The large diameter portion of the tunnel was 75 cm long. Most of the testing was performed at a flow rate of 15 l/min. The experimental investigation indicates that the flow field in the particular dilution tunnel tested has a persistent jet throughout its length, and this confined jet creates eddy recirculation zones which may cause the temperature and dilution histories of particles trapped in these eddies to be significantly different than particles which remain in the jet until extracted by the sample probe. Similarly, the location of the sample probe could also affect measured size distribution profiles, particularly if it were moved in or out of the path of the persistent jet. In addition to the simple tunnel geometry with a single abrupt expansion, a conical diffuser and a perforated plate were separately tested to investigate their effects on the tunnel fluid dynamics. The particular diffuser tested appeared to cause the jet to stall and therefore led to an even more unpredictable path for the fluid within. Limited testing with the perforated plate indicated that it increased the jet deceleration and laminarization, and therefore could lead to a more predictable flow path for aerosol sampled from the tunnel. (author)

  18. Electromagnetic model for near-field microwave microscope with atomic resolution: Determination of tunnel junction impedance

    SciTech Connect (OSTI)

    Reznik, Alexander N.

    2014-08-25

    An electrodynamic model is proposed for the tunneling microwave microscope with subnanometer space resolution as developed by Lee et al. [Appl. Phys. Lett. 97, 183111 (2010)]. Tip-sample impedance Z{sub a} was introduced and studied in the tunneling and non-tunneling regimes. At tunneling breakdown, the microwave current between probe and sample flows along two parallel channels characterized by impedances Z{sub p} and Z{sub t} that add up to form overall impedance Z{sub a}. Quantity Z{sub p} is the capacitive impedance determined by the near field of the probe and Z{sub t} is the impedance of the tunnel junction. By taking into account the distance dependences of effective tip radius r{sub 0}(z) and tunnel resistance R{sub t}(z)?=?Re[Z{sub t}(z)], we were able to explain the experimentally observed dependences of resonance frequency f{sub r}(z) and quality factor Q{sub L}(z) of the microscope. The obtained microwave resistance R{sub t}(z) and direct current tunnel resistance R{sub t}{sup dc}(z) exhibit qualitatively similar behavior, although being largely different in both magnitude and the characteristic scale of height dependence. Interpretation of the microwave images of the atomic structure of test samples proved possible by taking into account the inductive component of tunnel impedance ImZ{sub t}?=??L{sub t}. Relation ?L{sub t}/R{sub t}???0.235 was obtained.

  19. Can p-channel tunnel field-effect transistors perform as good as n-channel?

    SciTech Connect (OSTI)

    Verhulst, A. S. Pourghaderi, M. A.; Collaert, N.; Thean, A. V.-Y.; Verreck, D.; Van de Put, M.; Groeseneken, G.; Sore, B.

    2014-07-28

    We show that bulk semiconductor materials do not allow perfectly complementary p- and n-channel tunnel field-effect transistors (TFETs), due to the presence of a heavy-hole band. When tunneling in p-TFETs is oriented towards the gate-dielectric, field-induced quantum confinement results in a highest-energy subband which is heavy-hole like. In direct-bandgap IIIV materials, the most promising TFET materials, phonon-assisted tunneling to this subband degrades the subthreshold swing and leads to at least 10 smaller on-current than the desired ballistic on-current. This is demonstrated with quantum-mechanical predictions for p-TFETs with tunneling orthogonal to the gate, made out of InP, In{sub 0.53}Ga{sub 0.47}As, InAs, and a modified version of In{sub 0.53}Ga{sub 0.47}As with an artificially increased conduction-band density-of-states. We further show that even if the phonon-assisted current would be negligible, the build-up of a heavy-hole-based inversion layer prevents efficient ballistic tunneling, especially at low supply voltages. For p-TFET, a strongly confined n-i-p or n-p-i-p configuration is therefore recommended, as well as a tensily strained line-tunneling configuration.

  20. Atomistic Insights Into the Oriented Attachment of Tunnel-Based Oxide Nanostructures

    SciTech Connect (OSTI)

    Yuan, Yifei; Wood, Stephen M; He, Kun; Yao, Wentao; Tompsett, David; Lu, Jun; Nie, Anmin; Islam, M. Saiful; Shahbazian-Yassar, Reza

    2016-01-01

    Controlled synthesis of nanomaterials is one of the grand challenges facing materials scientists. In particular, how tunnel-based nanomaterials aggregate during synthesis while maintaining their well-aligned tunneled structure is not fully understood. Here, we describe the atomistic mechanism of oriented attachment (OA) during solution synthesis of tunneled α-MnO2 nanowires based on a combination of in situ liquid cell transmission electron microscopy (TEM), aberration-corrected scanning TEM with subangstrom spatial resolution, and first-principles calculations. It is found that primary tunnels (1 × 1 and 2 × 2) attach along their common {110} lateral surfaces to form interfaces corresponding to 2 × 3 tunnels that facilitate their short-range ordering. The OA growth of α-MnO2 nanowires is driven by the stability gained from elimination of {110} surfaces and saturation of Mn atoms at {110}-edges. During this process, extra [MnOx] radicals in solution link the two adjacent {110} surfaces and bond with the unsaturated Mn atoms from both surface edges to produce stable nanowire interfaces. Our results provide insights into the controlled synthesis and design of nanomaterials in which tunneled structures can be tailored for use in catalysis, ion exchange, and energy storage applications.

  1. MHK Technologies/Tunneled Wave Energy Converter TWEC | Open Energy...

    Open Energy Info (EERE)

    Water Column Technology Readiness Level Click here TRL 1-3: Discovery Concept Definition Early Stage Development & Design & Engineering Technology Description The...

  2. Selective p-i-n photodetector with resonant tunneling

    SciTech Connect (OSTI)

    Mil'shtein, S.; Wilson, S.; Pillai, A.

    2014-05-15

    There are different fundamental approaches to designing selective photodetectors, where the selectivity of optical spectra is produced by a filtering aperture. However, manufacturing of multilayered filters is cumbersome for epitaxial technology. In the current study, we offer a novel approach in design of selective photodetectors. A p-i-n photodetector with superlattices in top n-layer becomes transparent for photons where h?<>E{sub ng}+E{sub n1}, the light will be absorbed, simultaneously producing high energy (hot) electrons. The designed thickness of the structure does prevent thermal relaxation of high energy electrons by thus enhancing the selectivity of the photodetector. However the most important selectivity element is the resonant tunneling which does happen only for electrons occupying E{sub n1} energy levels as they transfer to levels E{sub i1}aligned under reverse biasing.

  3. Subgap biasing of superconducting tunnel junctions without a magnetic field

    SciTech Connect (OSTI)

    Segall, K.; Moyer, J.; Mazo, Juan J.

    2008-08-15

    Superconducting tunnel junctions (STJs) have been successfully used as single-photon detectors but require the use of a magnetic field to operate. A recent paper has proposed the idea to use a circuit of three junctions in place of a single junction in order to achieve the necessary biasing without applying a magnetic field. The nonlinear interaction between the different junctions in the circuit causes the existence of a stable subgap state for one of the junctions, which acts as the detector junction. In this paper, we present the first measurements demonstrating the existence of such a biasing state feasible for STJ detectors. Single junction measurements with an applied magnetic field help determine the functional form of the subgap current versus voltage; then the operating point of a three-junction circuit is measured and fit to theory. The excellent match between theory and experiment demonstrates the existence of the subgap biasing state. The outlook for possible use in detector applications is discussed.

  4. Potential long-term chemical effects of diesel fuel emissions on a mining environment: A preliminary assessment based on data from a deep subsurface tunnel at Rainer Mesa, Nevada test site

    SciTech Connect (OSTI)

    Meike, A.; Bourcier, W.L.; Alai, M.

    1995-09-01

    The general purpose of the Yucca Mountain Site Characterization Project (YMSCP) Introduced Materials Task is to understand and predict potential long-term modifications of natural water chemistry related to the construction and operation of a radioactive waste repository that may significantly affect performance of the waste packages. The present study focuses on diesel exhaust. Although chemical information on diesel exhaust exists in the literature, it is either not explicit or incomplete, and none of it establishes mechanisms that might be used to predict long-term behavior. In addition, the data regarding microbially mediated chemical reactions are not well correlated with the abiotic chemical data. To obtain some of the required long-term information, we chose a historical analog: the U12n tunnel at Rainier Mesa, Nevada Test Site. This choice was based on the tunnel`s extended (30-year) history of diesel usage, its geological similarity to Yucca Mountain, and its availability. The sample site within the tunnel was chosen based on visual inspection and on information gathered from miners who were present during tunnel operations. The thick layer of dark deposit at that site was assumed to consist primarily of rock powder and diesel exhaust. Surface samples and core samples were collected with an intent to analyze the deposit and to measure potential migration of chemical components into the rock. X-ray diffraction (XRD), x-ray fluorescence (XRF), scanning electron microscopy (SEM) with energy dispersive spectra (EDS) analysis, secondary-ion mass spectrometry (SIMS), and Fourier transform infrared (FTIR) analysis were used to measure both spatial distribution and concentration for the wide variety of chemical components that were expected based on our literature survey.

  5. Preliminary studies of tunnel interface response modeling using test data from underground storage facilities.

    SciTech Connect (OSTI)

    Sobolik, Steven Ronald; Bartel, Lewis Clark

    2010-11-01

    In attempting to detect and map out underground facilities, whether they be large-scale hardened deeply-buried targets (HDBT's) or small-scale tunnels for clandestine border or perimeter crossing, seismic imaging using reflections from the tunnel interface has been seen as one of the better ways to both detect and delineate tunnels from the surface. The large seismic impedance contrast at the tunnel/rock boundary should provide a strong, distinguishable seismic response, but in practice, such strong indicators are often lacking. One explanation for the lack of a good seismic reflection at such a strong contrast boundary is that the damage caused by the tunneling itself creates a zone of altered seismic properties that significantly changes the nature of this boundary. This report examines existing geomechanical data that define the extent of an excavation damage zone around underground tunnels, and the potential impact on rock properties such as P-wave and S-wave velocities. The data presented from this report are associated with sites used for the development of underground repositories for the disposal of radioactive waste; these sites have been excavated in volcanic tuff (Yucca Mountain) and granite (HRL in Sweden, URL in Canada). Using the data from Yucca Mountain, a numerical simulation effort was undertaken to evaluate the effects of the damage zone on seismic responses. Calculations were performed using the parallelized version of the time-domain finitedifference seismic wave propagation code developed in the Geophysics Department at Sandia National Laboratories. From these numerical simulations, the damage zone does not have a significant effect upon the tunnel response, either for a purely elastic case or an anelastic case. However, what was discovered is that the largest responses are not true reflections, but rather reradiated Stoneley waves generated as the air/earth interface of the tunnel. Because of this, data processed in the usual way may not

  6. The use of computer simulation to investigate tip shape and point contact effects during scanning tunneling microscopy of supported nanostructures

    SciTech Connect (OSTI)

    Mark, Geza I.; Biro, Laszlo P.; Gyulai, Jozsef; Thiry, Paul A.; Lambin, Philippe

    1999-09-30

    A recently developed computer code [1] is used to investigate effects which may arise during the STM investigation of supported nanostructures, like carbon nanotubes. The effects of tip geometry and point contact imaging are studied. The calculations show that while the magnitude of the tunnel current is determined by the tip-nanotube tunnel gap, the asymmetry of the tip {+-} current is influenced by the nanotube-support tunnel gap. The results obtained from simulation are compared with experimental data.

  7. Assessment of tunnel ground conditions for a two-year stand-by period, January 1994. UTAP report

    SciTech Connect (OSTI)

    1994-01-28

    This report summarizes observations, assessment of ground conditions, and recommendations pertaining to the Collider main ring tunnel at the Superconducting Super Collider (SSC).

  8. Chemical beam epitaxy growth of AlGaAs/GaAs tunnel junctions using trimethyl aluminium for multijunction solar cells

    SciTech Connect (OSTI)

    Paquette, B.; DeVita, M.; Turala, A.; Kolhatkar, G.; Boucherif, A.; Jaouad, A.; Aimez, V.; Ars, R.; Wilkins, M.; Wheeldon, J. F.; Walker, A. W.; Hinzer, K.; Fafard, S.

    2013-09-27

    AlGaAs/GaAs tunnel junctions for use in high concentration multijunction solar cells were designed and grown by chemical beam epitaxy (CBE) using trimethyl aluminium (TMA) as the p-dopant source for the AlGaAs active layer. Controlled hole concentration up to 4?10{sup 20} cm{sup ?3} was achieved through variation in growth parameters. Fabricated tunnel junctions have a peak tunneling current up to 6140 A/cm{sup 2}. These are suitable for high concentration use and outperform GaAs/GaAs tunnel junctions.

  9. Increased efficiency in multijunction solar cells through the incorporation of semimetallic ErAs nanoparticles into the tunnel junction

    SciTech Connect (OSTI)

    Zide, J.M.O.; Kleiman-Shwarsctein, A.; Strandwitz, N.C.; Zimmerman, J.D.; Steenblock-Smith, T.; Gossard, A.C.; Forman, A.; Ivanovskaya, A.; Stucky, G.D.

    2006-04-17

    We report the molecular beam epitaxy growth of Al{sub 0.3}Ga{sub 0.7}As/GaAs multijunction solar cells with epitaxial, semimetallic ErAs nanoparticles at the interface of the tunnel junction. The states provided by these nanoparticles reduce the bias required to pass current through the tunnel junction by three orders of magnitude, and therefore drastically reduce the voltage losses in the tunnel junction. We have measured open-circuit voltages which are 97% of the sum of the constituent cells, which result in nearly double the efficiency of our multijunction cell with a conventional tunnel junction.

  10. Reusing Water

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

    Reusing Water Reusing Water Millions of gallons of industrial wastewater is recycled at LANL by virtue of a long-term strategy to treat wastewater rather than discharging it into...

  11. Reusing Water

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

    Reusing Water Reusing Water Millions of gallons of industrial wastewater is recycled at LANL by virtue of a long-term strategy to treat wastewater rather than discharging it into ...

  12. Water Summit

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

    host Water Summit March 21, 2016 Los Alamos watershed research among featured projects LOS ALAMOS, N.M., March 21, 2016-On Tuesday, March 22, 2016-World Water Day-the ...

  13. A Historical Evaluation of the U16a Tunnel, Nevada National Security Site, Nye County, Nevada Volume 2

    SciTech Connect (OSTI)

    Jones, Roberrt C; Drollinger, Harold

    2013-06-01

    This report presents a historical evaluation of the U16a Tunnel on the Nevada National Security Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency. The U16a Tunnel was used for underground nuclear weapons effects tests in Shoshone Mountain in Area 16 of the Nevada National Security Site. Six nuclear tests were conducted in the U16a Tunnel from 1962 to 1971. These tests are Marshmallow, Gum Drop, Double Play, Ming Vase, Diamond Dust, and Diamond Mine. The U.S. Department of Defense Threat Reduction Agency, with participation from Lawrence Livermore National Laboratory and Las Alamos National Laboratory, sponsored the tests. Fifteen high explosives tests were also conducted at the tunnel. Two were calibration tests during nuclear testing and the remaining were U.S. Department of Defense, Defense Threat Reduction Agency tunnel defeat tests. The U16a Tunnel complex is on the top and slopes of Shoshone Mountain, encompassing an area of approximately 16.7 hectares (41.1 acres). Major modifications to the landscape are a result of three principal activities, road construction and maintenance, mining activities related to development of the tunnel complex, and site preparation for activities related to testing. Forty-seven cultural features were recorded at the portal and on the slopes of Shoshone Mountain. At the portal area, features relate to the mining, construction, testing, and general every day operational support activities within the tunnel. These include concrete foundations for buildings, equipment pads, and rail lines. Features on the slopes above the tunnel relate to tunnel ventilation, borehole drilling, and data recording. Feature types include soil-covered bunkers, concrete foundations, instrument cable holes, drill holes, and ventilation shafts. The U16

  14. A Historical Evaluation of the U16a Tunnel, Nevada National Security Site, Nye County, Nevada Volume 1

    SciTech Connect (OSTI)

    Jones, robert C; Drollinger, Harold; Bullard, Thomas F; Ashbaugh, Laurence J; Griffin, Wayne R

    2013-06-01

    This report presents a historical evaluation of the U16a Tunnel on the Nevada National Security Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency. The U16a Tunnel was used for underground nuclear weapons effects tests in Shoshone Mountain in Area 16 of the Nevada National Security Site. Six nuclear tests were conducted in the U16a Tunnel from 1962 to 1971. These tests are Marshmallow, Gum Drop, Double Play, Ming Vase, Diamond Dust, and Diamond Mine. The U.S. Department of Defense Threat Reduction Agency, with participation from Lawrence Livermore National Laboratory and Las Alamos National Laboratory, sponsored the tests. Fifteen high explosives tests were also conducted at the tunnel. Two were calibration tests during nuclear testing and the remaining were U.S. Department of Defense, Defense Threat Reduction Agency tunnel defeat tests. The U16a Tunnel complex is on the top and slopes of Shoshone Mountain, encompassing an area of approximately 16.7 hectares (41.1 acres). Major modifications to the landscape are a result of three principal activities, road construction and maintenance, mining activities related to development of the tunnel complex, and site preparation for activities related to testing. Forty-seven cultural features were recorded at the portal and on the slopes of Shoshone Mountain. At the portal area, features relate to the mining, construction, testing, and general every day operational support activities within the tunnel. These include concrete foundations for buildings, equipment pads, and rail lines. Features on the slopes above the tunnel relate to tunnel ventilation, borehole drilling, and data recording. Feature types include soil-covered bunkers, concrete foundations, instrument cable holes, drill holes, and ventilation shafts. The U16

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

    DOE Patents [OSTI]

    Forrest, Stephen R.

    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.

  16. Large-scale fabrication of BN tunnel barriers for graphene spintronics

    SciTech Connect (OSTI)

    Fu, Wangyang; Makk, Péter; Maurand, Romain; Bräuninger, Matthias; Schönenberger, Christian

    2014-08-21

    We have fabricated graphene spin-valve devices utilizing scalable materials made from chemical vapor deposition (CVD). Both the spin-transporting graphene and the tunnel barrier material are CVD-grown. The tunnel barrier is realized by Hexagonal boron nitride, used either as a monolayer or bilayer and placed over the graphene. Spin transport experiments were performed using ferromagnetic contacts deposited onto the barrier. We find that spin injection is still greatly suppressed in devices with a monolayer tunneling barrier due to resistance mismatch. This is, however, not the case for devices with bilayer barriers. For those devices, a spin relaxation time of ∼260 ps intrinsic to the CVD graphene material is deduced. This time scale is comparable to those reported for exfoliated graphene, suggesting that this CVD approach is promising for spintronic applications which require scalable materials.

  17. Tunneling spectroscopy of Al/AlO{sub x}/Pb subjected to hydrostatic pressure

    SciTech Connect (OSTI)

    Zhu, Jun; Hou, Xing-Yuan; Guan, Tong; Zhang, Qin-Tong; Li, Yong-Qing; Han, Xiu-Feng; Li, Chun-Hong; Ren, Cong; Yang, Zheng-Xin; Zhang, Jin; Shan, Lei; Chen, Gen-Fu

    2015-05-18

    We develop an experimental tool to investigate high-pressure electronic density of state by combining electron tunneling spectroscopy measurements with high-pressure technique. It is demonstrated that tunneling spectroscopy measurement on Al/AlO{sub x}/Pb junction is systematically subjected to hydrostatic pressure up to 2.2 GPa. Under such high pressure, the normal state junction resistance is sensitive to the applied pressure, reflecting the variation of band structure of the barrier material upon pressures. In superconducting state, the pressure dependence of the energy gap Δ{sub 0}, the gap ratio 2Δ{sub 0}/k{sub B}T{sub c}, and the phonon spectral energy is extracted and compared with those obtained in the limited pressure range. Our experimental results show the accessibility and validity of high pressure tunneling spectroscopy, offering wealthy information about high pressure superconductivity.

  18. Controlling spin-dependent tunneling by bandgap tuning in epitaxial rocksalt MgZnO films

    SciTech Connect (OSTI)

    Li, D. L.; Ma, Q. L.; Wang, S. G.; Ward, R. C. C.; Hesjedal, T.; Zhang, X. -G.; Kohn, A.; Amsellem, E.; Yang, G.; Liu, J. L.; Jiang, J.; Wei, H. X.; Han, X. F.

    2014-12-02

    Widespread application of magnetic tunnel junctions (MTJs) for information storage has so far been limited by the complicated interplay between tunnel magnetoresistance (TMR) ratio and the product of resistance and junction area (RA). An intricate connection exists between TMR ratio, RA value and the bandgap and crystal structure of the barrier, a connection that must be unravelled to optimise device performance and enable further applications to be developed. In this paper, we demonstrate a novel method to tailor the bandgap of an ultrathin, epitaxial Zn-doped MgO tunnel barrier with rocksalt structure. This structure is attractive due to its good Δ1 spin filtering effect, and we show that MTJs based on tunable MgZnO barriers allow effective balancing of TMR ratio and RA value. Finally, in this way spin-dependent transport properties can be controlled, a key challenge for the development of spintronic devices.

  19. Controlling spin-dependent tunneling by bandgap tuning in epitaxial rocksalt MgZnO films

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

    Li, D. L.; Ma, Q. L.; Wang, S. G.; Ward, R. C. C.; Hesjedal, T.; Zhang, X. -G.; Kohn, A.; Amsellem, E.; Yang, G.; Liu, J. L.; et al

    2014-12-02

    Widespread application of magnetic tunnel junctions (MTJs) for information storage has so far been limited by the complicated interplay between tunnel magnetoresistance (TMR) ratio and the product of resistance and junction area (RA). An intricate connection exists between TMR ratio, RA value and the bandgap and crystal structure of the barrier, a connection that must be unravelled to optimise device performance and enable further applications to be developed. In this paper, we demonstrate a novel method to tailor the bandgap of an ultrathin, epitaxial Zn-doped MgO tunnel barrier with rocksalt structure. This structure is attractive due to its good Δ1more » spin filtering effect, and we show that MTJs based on tunable MgZnO barriers allow effective balancing of TMR ratio and RA value. Finally, in this way spin-dependent transport properties can be controlled, a key challenge for the development of spintronic devices.« less

  20. New Hypersonic Shock Tunnel at the Laboratory of Aerothermodynamics and Hypersonics Prof. Henry T. Nagamatsu

    SciTech Connect (OSTI)

    Toro, P. G. P.; Minucci, M. A. S.; Chanes, J. B. Jr; Oliveira, A. C.; Gomes, F. A. A.; Myrabo, L. N.; Nagamatsu, Henry T.

    2008-04-28

    The new 0.60-m. nozzle exit diameter hypersonic shock tunnel was designed to study advanced air-breathing propulsion system such as supersonic combustion and/or laser technologies. In addition, it may be used for hypersonic flow studies and investigations of the electromagnetic (laser) energy addition for flow control. This new hypersonic shock tunnel was designed and installed at the Laboratory for of Aerothermodynamics and Hypersonics Prof. Henry T. Nagamatsu, IEAv-CTA, Brazil. The design of the tunnel enables relatively long test times, 2-10 milliseconds, suitable for the experiments performed at the laboratory. Free stream Mach numbers ranging from 6 to 25 can be produced and stagnation pressures and temperatures up to 360 atm. and up to 9,000 K, respectively, can be generated. Shadowgraph and schlieren optical techniques will be used for flow visualization.

  1. Giant amplification of tunnel magnetoresistance in a molecular junction: Molecular spin-valve transistor

    SciTech Connect (OSTI)

    Dhungana, Kamal B.; Pati, Ranjit

    2014-04-21

    Amplification of tunnel magnetoresistance by gate field in a molecular junction is the most important requirement for the development of a molecular spin valve transistor. Herein, we predict a giant amplification of tunnel magnetoresistance in a single molecular spin valve junction, which consists of Ru-bis-terpyridine molecule as a spacer between two ferromagnetic nickel contacts. Based on the first-principles quantum transport approach, we show that a modest change in the gate field that is experimentally accessible can lead to a substantial amplification (320%) of tunnel magnetoresistance. The origin of such large amplification is attributed to the spin dependent modification of orbitals at the molecule-lead interface and the resultant Stark effect induced shift in channel position with respect to the Fermi energy.

  2. Two-band lasing in epitaxially stacked tunnel-junction semiconductor lasers

    SciTech Connect (OSTI)

    Vinokurov, D. A.; Ladugin, M. A.; Lyutetskii, A. V.; Marmalyuk, A. A.; Petrunov, A. N.; Pikhtin, N. A.; Slipchenko, S. O. Sokolova, Z. N.; Stankevich, A. L.; Fetisova, N. V.; Shashkin, I. S.; Averkiev, N. S.; Tarasov, I. S.

    2010-06-15

    Epitaxially stacked tunnel-junction laser hetero structures were grown by hydride metalorganic vapor-phase epitaxy in the system of AlGaAs/GaAs/In GaAs alloys. Based on such structures, mesa stripe lasers with an aperture of 150 s- 7 m were fabricated. The possibility of controlling the lasing wavelength by varying the active region thickness in each tunnel-junction laser structure was demonstrated. Independent two-band lasing at wavelengths of 914 and 925 nm (the difference frequency is 2.3 THz) was achieved at a maximum optical radiation power of 20 W in each band of the epitaxially stacked tunnel-junction semiconductor laser.

  3. Multiferroic tunnel junctions and ferroelectric control of magnetic state at interface (invited)

    SciTech Connect (OSTI)

    Yin, Y. W.; Raju, M.; Li, Qi; Hu, W. J.; Burton, J. D.; Gruverman, A.; Tsymbal, E. Y.; Kim, Y.-M.; Borisevich, A. Y.; Pennycook, S. J.; Yang, S. M.; Noh, T. W.; Li, X. G.; Zhang, Z. D.

    2015-05-07

    As semiconductor devices reach ever smaller dimensions, the challenge of power dissipation and quantum effect place a serious limit on the future device scaling. Recently, a multiferroic tunnel junction (MFTJ) with a ferroelectric barrier sandwiched between two ferromagnetic electrodes has drawn enormous interest due to its potential applications not only in multi-level data storage but also in electric field controlled spintronics and nanoferronics. Here, we present our investigations on four-level resistance states, giant tunneling electroresistance (TER) due to interfacial magnetoelectric coupling, and ferroelectric control of spin polarized tunneling in MFTJs. Coexistence of large tunneling magnetoresistance and TER has been observed in manganite/(Ba, Sr)TiO{sub 3}/manganite MFTJs at low temperatures and room temperature four-resistance state devices were also obtained. To enhance the TER for potential logic operation with a magnetic memory, La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/BaTiO{sub 3}/La{sub 0.5}Ca{sub 0.5}MnO{sub 3} /La{sub 0.7}Sr{sub 0.3}MnO{sub 3} MFTJs were designed by utilizing a bilayer tunneling barrier in which BaTiO{sub 3} is ferroelectric and La{sub 0.5}Ca{sub 0.5}MnO{sub 3} is close to ferromagnetic metal to antiferromagnetic insulator phase transition. The phase transition occurs when the ferroelectric polarization is reversed, resulting in an increase of TER by two orders of magnitude. Tunneling magnetoresistance can also be controlled by the ferroelectric polarization reversal, indicating strong magnetoelectric coupling at the interface.

  4. Tunneling splitting in double-proton transfer: Direct diagonalization results for porphycene

    SciTech Connect (OSTI)

    Smedarchina, Zorka; Siebrand, Willem; Fernández-Ramos, Antonio

    2014-11-07

    Zero-point and excited level splittings due to double-proton tunneling are calculated for porphycene and the results are compared with experiment. The calculation makes use of a multidimensional imaginary-mode Hamiltonian, diagonalized directly by an effective reduction of its dimensionality. Porphycene has a complex potential energy surface with nine stationary configurations that allow a variety of tunneling paths, many of which include classically accessible regions. A symmetry-based approach is used to show that the zero-point level, although located above the cis minimum, corresponds to concerted tunneling along a direct trans − trans path; a corresponding cis − cis path is predicted at higher energy. This supports the conclusion of a previous paper [Z. Smedarchina, W. Siebrand, and A. Fernández-Ramos, J. Chem. Phys. 127, 174513 (2007)] based on the instanton approach to a model Hamiltonian of correlated double-proton transfer. A multidimensional tunneling Hamiltonian is then generated, based on a double-minimum potential along the coordinate of concerted proton motion, which is newly evaluated at the RI-CC2/cc-pVTZ level of theory. To make it suitable for diagonalization, its dimensionality is reduced by treating fast weakly coupled modes in the adiabatic approximation. This results in a coordinate-dependent mass of tunneling, which is included in a unique Hermitian form into the kinetic energy operator. The reduced Hamiltonian contains three symmetric and one antisymmetric mode coupled to the tunneling mode and is diagonalized by a modified Jacobi-Davidson algorithm implemented in the Jadamilu software for sparse matrices. The results are in satisfactory agreement with the observed splitting of the zero-point level and several vibrational fundamentals after a partial reassignment, imposed by recently derived selection rules. They also agree well with instanton calculations based on the same Hamiltonian.

  5. Thin films of metal oxides on metal single crystals: Structure and growth by scanning tunneling microscopy

    SciTech Connect (OSTI)

    Galloway, H.C.

    1995-12-01

    Detailed studies of the growth and structure of thin films of metal oxides grown on metal single crystal surfaces using Scanning Tunneling Microscopy (STM) are presented. The oxide overlayer systems studied are iron oxide and titanium oxide on the Pt(III) surface. The complexity of the metal oxides and large lattice mismatches often lead to surface structures with large unit cells. These are particularly suited to a local real space technique such as scanning tunneling microscopy. In particular, the symmetry that is directly observed with the STM elucidates the relationship of the oxide overlayers to the substrate as well as distinguishing, the structures of different oxides.

  6. B61-12 Life Extension Program Undergoes First Full-Scale Wind Tunnel Test |

    National Nuclear Security Administration (NNSA)

    National Nuclear Security Administration | (NNSA) B61-12 Life Extension Program Undergoes First Full-Scale Wind Tunnel Test April 14, 2014 WASHINGTON, D.C. - The National Nuclear Security Administration (NNSA) announced today that its Sandia National Laboratories successfully completed the first full-scale wind tunnel test of the B61-12 as part of the NNSA's ongoing effort to refurbish the B61 nuclear bomb. The purpose of this test was to characterize counter torque, the interaction between

  7. A Monolithic Interconnected module with a tunnel Junction for Enhanced Electrical and Optical Performance

    SciTech Connect (OSTI)

    Murray, Christopher Sean; Wilt, David Morgan

    1999-06-30

    An improved thermophotovoltaic (TPV) n/p/n device is provided. Monolithic Interconnected Modules (MIMs), semiconductor devices converting infrared radiation to electricity, have been developed with improved electrical and optical performance. The structure is an n-type emitter on a p-type base with an n-type lateral conduction layer. The incorporation of a tunnel junction and the reduction in the amount of p-type material used results in negligible parasitic absorption, decreased series resistance, increased voltage and increased active area. The novel use of a tunnel junction results in the potential for a TPV device with efficiency greater than 24%.

  8. Negative differential resistance in GaN tunneling hot electron transistors

    SciTech Connect (OSTI)

    Yang, Zhichao; Nath, Digbijoy; Rajan, Siddharth

    2014-11-17

    Room temperature negative differential resistance is demonstrated in a unipolar GaN-based tunneling hot electron transistor. Such a device employs tunnel-injected electrons to vary the electron energy and change the fraction of reflected electrons, and shows repeatable negative differential resistance with a peak to valley current ratio of 7.2. The device was stable when biased in the negative resistance regime and tunable by changing collector bias. Good repeatability and double-sweep characteristics at room temperature show the potential of such device for high frequency oscillators based on quasi-ballistic transport.

  9. Thin-film metal coated insulation barrier in a Josephson tunnel junction. [Patent application

    DOE Patents [OSTI]

    Hawkins, G.A.; Clarke, J.

    1975-10-31

    A highly stable, durable, and reproducible Josephson tunnel junction consists of a thin-film electrode of a hard superconductor, a thin oxide insulation layer over the electrode constituting a Josephson tunnel junction barrier, a thin-film layer of stabilizing metal over the barrier, and a second thin-film hard superconductive electrode over the stabilizing film. The thin stabilizing metal film is made only thick enough to limit penetration of the electrode material through the insulation layer so as to prevent a superconductive short.

  10. Note: Long-range scanning tunneling microscope for the study of nanostructures on insulating substrates

    SciTech Connect (OSTI)

    Molina-Mendoza, Aday J.; Rodrigo, Jos G.; Rubio-Bollinger, Gabino; Island, Joshua; Burzuri, Enrique; Zant, Herre S. J. van der; Agrat, Nicols; Condensed Matter Physics Center and Instituto Universitario de Ciencia de Materiales Nicols Cabrera, Universidad Autnoma de Madrid, Campus de Cantoblanco, E-28049 Madrid; Instituto Madrileo de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid

    2014-02-15

    The scanning tunneling microscope (STM) is a powerful tool for studying the electronic properties at the atomic level, however, it is of relatively small scanning range and the fact that it can only operate on conducting samples prevents its application to study heterogeneous samples consisting of conducting and insulating regions. Here we present a long-range scanning tunneling microscope capable of detecting conducting micro and nanostructures on insulating substrates using a technique based on the capacitance between the tip and the sample and performing STM studies.

  11. Using tevatron magnets for HE-LHC or new ring in LHC tunnel

    SciTech Connect (OSTI)

    Piekarz, Henryk; /Fermilab

    2011-08-01

    Two injector accelerator options for HE-LHC of p{sup +} - p{sup +} collisions at 33 TeV cms energy are briefly outlined. One option is based on the Super-SPS (S-SPS) accelerator in the SPS tunnel, and the other one is based on the LER (Low-Energy-Ring) accelerator in the LHC tunnel. Expectations of performance of the main arc accelerator magnets considered for the construction of the S-SPS and of the LER accelerators are used to tentatively devise some selected properties of these accelerators as potential injectors to HE-LHC.

  12. Monolithic interconnected module with a tunnel junction for enhanced electrical and optical performance

    DOE Patents [OSTI]

    Murray, Christopher S.; Wilt, David M.

    2000-01-01

    An improved thermophotovoltaic (TPV) n/p/n device is provided. Monolithic Interconnected Modules (MIMS), semiconductor devices converting infrared radiation to electricity, have been developed with improved electrical and optical performance. The structure is an n-type emitter on a p-type base with an n-type lateral conduction layer. The incorporation of a tunnel junction and the reduction in the amount of p-type material used results in negligible parasitic absorption, decreased series resistance, increased voltage and increased active area. The novel use of a tunnel junction results in the potential for a TPV device with efficiency greater than 24%.

  13. Tunneling characteristics in chemical vapor deposited graphenehexagonal boron nitridegraphene junctions

    SciTech Connect (OSTI)

    Roy, T.; Hesabi, Z. R.; Joiner, C. A.; Vogel, E. M. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332 (United States); Liu, L.; Gu, G. [Department of Electrical Engineering and Computer Science, University of Tennessee, 1520 Middle Drive, Knoxville, Tennessee 37996 (United States); Barrera, S. de la; Feenstra, R. M. [Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States); Chakrabarti, B. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332 (United States); Department of Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Rd., Richardson, Texas 75080 (United States)

    2014-03-24

    Large area chemical vapor deposited graphene and hexagonal boron nitride was used to fabricate graphenehexagonal boron nitridegraphene symmetric field effect transistors. Gate control of the tunneling characteristics is observed similar to previously reported results for exfoliated graphenehexagonal boron nitridegraphene devices. Density-of-states features are observed in the tunneling characteristics of the devices, although without large resonant peaks that would arise from lateral momentum conservation. The lack of distinct resonant behavior is attributed to disorder in the devices, and a possible source of the disorder is discussed.

  14. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode

    SciTech Connect (OSTI)

    Pettinari, G., E-mail: giorgio.pettinari@cnr.it [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); National Research Council (CNR), Institute for Photonics and Nanotechnologies (IFN-CNR), Via Cineto Romano 42, 00156 Roma (Italy); Balakrishnan, N.; Makarovsky, O.; Campion, R. P.; Patan, A. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)] [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Polimeni, A.; Capizzi, M. [CNISM-Dipartimento di Fisica, Sapienza Universit di Roma, P.le A. Moro 2, 00185 Roma (Italy)] [CNISM-Dipartimento di Fisica, Sapienza Universit di Roma, P.le A. Moro 2, 00185 Roma (Italy)

    2013-12-09

    We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30??m for a bias increment of 0.2?V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity.

  15. Effects of boron composition on tunneling magnetoresistance ratio and microstructure of CoFeB/MgO/CoFeB pseudo-spin-valve magnetic tunnel junctions

    SciTech Connect (OSTI)

    Kodzuka, M.; Ohkubo, T.; Hono, K.; Ikeda, S.; Ohno, H.; Gan, H. D.

    2012-02-15

    The effect of B concentration on the tunneling magnetoresistance (TMR) of (Co{sub 25}Fe{sub 75}){sub 100-x}B{sub x}/MgO/(Co{sub 25}Fe{sub 75}){sub 100-x}B{sub x} (x = 22 and 33) pseudo-spin-valve (P-SV) magnetic tunnel junctions (MTJs) was investigated. The TMR ratios for optimally annealed MTJs with x = 22 and 33 were 340% and 170%, respectively, at room temperature. High resolution transmission electron microscopy (HRTEM) observation showed a weaker (001) texture in the MgO barrier in the MTJ with x = 33. The bottom electrode was not fully crystallized even with a considerable amount of B in the (Co{sub 25}Fe{sub 75}){sub 67}B{sub 33}, while good epitaxy was observed between (001) textured MgO and (Co{sub 25}Fe{sub 75}){sub 78}B{sub 22} electrodes.

  16. Water pollution

    SciTech Connect (OSTI)

    Not Available

    1990-06-01

    Ballast water, which is sea water that is carried in oil tankers to provide stability, can become contaminated with oil. Alyeska Pipeline Service Company runs a water treatment plant at its pipeline terminal at Prot Valdez, Alaska, to treat ballast water before it is discharged into the sea. GAO reviewed EPA's recently reissued National Pollution Discharge Elimination System permit for the Port Valdez facility. In this report, GAO compares the effluent limits and other requirements under the reissued permit with those of the old permit, determines the reasons for changes in the reissued permit, and examines Alyeska's initial efforts to comply with the reissued permit's effluent limits and reporting requirements.

  17. The tunneling solutions of the time-dependent Schroedinger equation for a square-potential barrier

    SciTech Connect (OSTI)

    Elci, A.; Hjalmarson, H. P.

    2009-10-15

    The exact tunneling solutions of the time-dependent Schroedinger equation with a square-potential barrier are derived using the continuous symmetry group G{sub S} for the partial differential equation. The infinitesimal generators and the elements for G{sub S} are represented and derived in the jet space. There exist six classes of wave functions. The representative (canonical) wave functions for the classes are labeled by the eigenvalue sets, whose elements arise partially from the reducibility of a Lie subgroup G{sub LS} of G{sub S} and partially from the separation of variables. Each eigenvalue set provides two or more time scales for the wave function. The ratio of two time scales can act as the duration of an intrinsic clock for the particle motion. The exact solutions of the time-dependent Schroedinger equation presented here can produce tunneling currents that are orders of magnitude larger than those produced by the energy eigenfunctions. The exact solutions show that tunneling current can be quantized under appropriate boundary conditions and tunneling probability can be affected by a transverse acceleration.

  18. Response of a Spent Fuel Transportation Cask to a Tunnel Fire Event

    SciTech Connect (OSTI)

    Bajwa, C. S.

    2003-02-25

    The staff of the Spent Fuel Project Office at the U.S. Nuclear Regulatory Commission undertook the investigation and thermal analysis of the Baltimore tunnel fire event. This event occurred in the Howard Street tunnel, in Baltimore, Maryland, on July 18, 2001. The staff was tasked with assessing the consequences of this event on the transportation of spent nuclear fuel. This paper describes the staff's coordination with the following government and laboratory organizations: the National Transportation Safety Board (NTSB), to determine the details of the train derailment and fire; the National Institute of Standards and Technology (NIST), to quantify the thermal conditions within the tunnel; the Center for Nuclear Waste Regulatory Analysis (CNWRA), to validate the NIST evaluations, and the Pacific Northwest National Laboratory (PNNL), to assist in the thermal analysis. The results of the staff's review and analysis efforts are also discussed. The staff has concluded that had the spent fuel transportation cask analyzed, a design approved under 10 CFR Part 71, been subjected to the Howard Street tunnel fire, no release of radioactive materials would have resulted from this postulated event, and the health and safety of the public would have been maintained.

  19. Simultaneous topographic and elemental chemical and magnetic contrast in scanning tunneling microscopy

    DOE Patents [OSTI]

    Rose, Volker; Preissner, Curt A; Hla, Saw-Wai; Wang, Kangkang; Rosenmann, Daniel

    2014-09-30

    A method and system for performing simultaneous topographic and elemental chemical and magnetic contrast analysis in a scanning, tunneling microscope. The method and system also includes nanofabricated coaxial multilayer tips with a nanoscale conducting apex and a programmable in-situ nanomanipulator to fabricate these tips and also to rotate tips controllably.

  20. Fermionic Tunneling Effect and Hawking Radiation in a Non Commutative FRW Universe

    SciTech Connect (OSTI)

    Bouhalouf, H.; Aissaoui, H.; Mebarki, N.

    2010-10-31

    The formalism of a non commutative gauge gravity is applied to an FRW universe and the corresponding modified metric, veirbein and spin connection components are obtained. Moreover, using the Hamilton-Jacobi method and as a pure space-time deformation effect, the NCG Hawking radiation via a fermionic tunneling transition through the dynamical NCG horizon is also studied.

  1. Superconductive tunnel junction device with enhanced characteristics and method of manufacture

    SciTech Connect (OSTI)

    Kroger, H.; Jillie, D. W.

    1985-08-20

    A superconductive tunnel junction device comprises first and second superconductive electrodes with a barrier disposed therebetween where the first superconductive electrode and the barrier are formed without interruption in the same vacuum system pump down and with the first superconductive electrode subjected to sputter etching in an argon plasma before the deposition of the barrier for improving the characteristics of the device.

  2. Resonant spin tunneling in randomly oriented nanospheres of Mn12 acetate

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

    Lendínez, S.; Zarzuela, R.; Tejada, J.; Terban, M. W.; Billinge, S. J. L.; Espin, J.; Imaz, I.; Maspoch, D.; Chudnovsky, E. M.

    2015-01-06

    We report measurements and theoretical analysis of resonant spin tunneling in randomly oriented nanospheres of a molecular magnet. Amorphous nanospheres of Mn₁₂ acetate have been fabricated and characterized by chemical, infrared, TEM, X-ray, and magnetic methods. Magnetic measurements have revealed sharp tunneling peaks in the field derivative of the magnetization that occur at the typical resonant field values for the Mn₁₂ acetate crystal in the field parallel to the easy axis.Theoretical analysis is provided that explains these observations. We argue that resonant spin tunneling in a molecular magnet can be established in a powder sample, without the need for amore » single crystal and without aligning the easy magnetization axes of the molecules. This is confirmed by re-analyzing the old data on a powdered sample of non-oriented micron-size crystals of Mn₁₂ acetate. In conclusion, our findings can greatly simplify the selection of candidates for quantum spin tunneling among newly synthesized molecular magnets.« less

  3. WATER TREATMENT

    DOE Patents [OSTI]

    Pitman, R.W.; Conley, W.R. Jr.

    1962-12-01

    An automated system for adding clarifying chemicals to water in a water treatment plant is described. To a sample of the floc suspension polyacrylamide or similar filter aid chemicals are added, and the sample is then put through a fast filter. The resulting filtrate has the requisite properties for monitoring in an optical turbidimeter to control the automated system. (AEC)

  4. Water Wars

    Energy Science and Technology Software Center (OSTI)

    2012-09-11

    Sandia National Laboratories and Intel Corporation are cooperating on a project aimed at developing serious games to assist in resource planners in conducting open and participatory projects. Water Wars serves as a prototype game focused on water issues. Water Wars is a multi-player, online role-playing "serious game" combining large-scale simulation (e.g. SimCity), with strategy and interpersonal interaction (e.g. Diplomacy). The game is about water use set in present-day New Mexico. Players enact various stakeholder rolesmore » and compete for water while simultaneously cooperating to prevent environmental collapse. The gamespace utilizes immersive 3D graphics to bring the problem alive. The game integrates Intel's OpenSim visualization engine with Sandia developed agent-based and system dynamics models.« less

  5. A Measurement System for Systematic Hydrological Characterization of Unsaturated Fractured Welded Tuff in a Mined Underground Tunnel

    SciTech Connect (OSTI)

    R. J. Cook; R. Salve; B.M. Freifeld; Y.W. Tsang

    2001-11-21

    A field investigation of unsaturated flow through a lithophysal unit of fractured welded tuff containing lithophysal cavities has been initiated. To characterize flow in this spatially heterogeneous medium, a systematic approach has been developed to perform tests in boreholes drilled at regular intervals in an underground tunnel (drift). In this paper, we describe the test equipment system that has been built for this purpose. Since the field-scale measurements, of liquid flow in the unsaturated, fractured rocks, require continuous testing for periods of days to weeks, the control of test equipment has been fully automated, allowing operation with no human presence at the field site. Preliminary results from the first set of tests are described. These tests give insight into the role of the matrix (perhaps also lithophysal cavities) as potential storage during the initial transient flow prior to the breakthrough of water at the drift crown, as well as the role of connected fractures that provide the subsequent quasi-steady flow. These tests also reveal the impact of evaporation on seepage into the drift.

  6. Interface characterization of epitaxial Fe/MgO/Fe magnetic tunnel junctions

    SciTech Connect (OSTI)

    Wang, Shouguo; Ward, R. C. C.; Zhang, Xiaoguang; Kohn, A.; Ma, Q. L.; Zhang, J.; Liu, H. F.; Han, Prof. X. F.

    2012-01-01

    Following predictions by first-principles theory of huge tunnel magnetoresistance (TMR) effect in epitaxial Fe/MgO/Fe magnetic tunnel junctions (MTJs), measured magnetoresistance (MR) ratio about 200% at room temperature (RT) have been reported in MgO-based epitaxial MTJs. Recently, MR ratio of about 600% has been reported at RT in MgO-based amorphous MTJs with core structure of CoFeB/MgO/CoFeB grown by magnetron sputtering with amorphous CoFeB layers. The sputtered CoFeB/MgO/CoFeB MTJs shows a great potential application in spintronic devices. Although epitaxial structure will probably not be used in devices, it remains an excellent model system to compare theoretical calculations with experimental results and to enhance our understanding of the spin dependent tunneling. Both theoretical calculations and experimental results clearly indicate that the interfacial structure plays a crucial role on coherent tunneling across single crystalMgO barrier, especially in epitaxial MgO-based MTJs grown by molecular beam epitaxy (MBE). Surface X-ray diffraction, Auger electron spectroscopy, X-ray absorption spectra, and X-ray magnetic circular dichroism have been used for interface characterization. However, no consistent viewpoint has been reached, and this is still an open issue. In this article, recent studies on the interface characterization in MgO-based epitaxial MTJs will be introduced, with a focus on research by X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and spin dependent tunneling spectroscopy.

  7. Estimation of deformation and stiffness of fractures close to tunnels using data from single-hole hydraulic testing and grouting

    SciTech Connect (OSTI)

    Fransson, A.; Tsang, C.-F.; Rutqvist, J.; Gustafson, G.

    2010-05-01

    Sealing of tunnels in fractured rocks is commonly performed by pre- or post-excavation grouting. The grouting boreholes are frequently drilled close to the tunnel wall, an area where rock stresses can be low and fractures can more easily open up during grout pressurization. In this paper we suggest that data from hydraulic testing and grouting can be used to identify grout-induced fracture opening, to estimate fracture stiffness of such fractures, and to evaluate its impact on the grout performance. A conceptual model and a method are presented for estimating fracture stiffness. The method is demonstrated using grouting data from four pre-excavation grouting boreholes at a shallow tunnel (50 m) in Nygard, Sweden, and two post-excavation grouting boreholes at a deep tunnel (450 m) in Aespoe HRL, Sweden. The estimated stiffness of intersecting fractures for the boreholes at the shallow Nygard tunnel are low (2-5 GPa/m) and in agreement with literature data from field experiments at other fractured rock sites. Higher stiffness was obtained for the deeper tunnel boreholes at Aespoe which is reasonable considering that generally higher rock stresses are expected at greater depths. Our method of identifying and evaluating the properties and impact of deforming fractures might be most applicable when grouting takes place in boreholes adjacent to the tunnel wall, where local stresses might be low and where deforming (opening) fractures may take most of the grout.

  8. Integrating atomic layer deposition and ultra-high vacuum physical vapor deposition for in situ fabrication of tunnel junctions

    SciTech Connect (OSTI)

    Elliot, Alan J. E-mail: jwu@ku.edu; Malek, Gary A.; Lu, Rongtao; Han, Siyuan; Wu, Judy Z. E-mail: jwu@ku.edu; Yu, Haifeng; Zhao, Shiping

    2014-07-15

    Atomic Layer Deposition (ALD) is a promising technique for growing ultrathin, pristine dielectrics on metal substrates, which is essential to many electronic devices. Tunnel junctions are an excellent example which require a leak-free, ultrathin dielectric tunnel barrier of typical thickness around 1 nm between two metal electrodes. A challenge in the development of ultrathin dielectric tunnel barriers using ALD is controlling the nucleation of dielectrics on metals with minimal formation of native oxides at the metal surface for high-quality interfaces between the tunnel barrier and metal electrodes. This poses a critical need for integrating ALD with ultra-high vacuum (UHV) physical vapor deposition. In order to address these challenges, a viscous-flow ALD chamber was designed and interfaced to an UHV magnetron sputtering chamber via a load lock. A sample transportation system was implemented for in situ sample transfer between the ALD, load lock, and sputtering chambers. Using this integrated ALD-UHV sputtering system, superconductor-insulator-superconductor (SIS) Nb-Al/Al{sub 2}O{sub 2}/Nb Josephson tunnel junctions were fabricated with tunnel barriers of thickness varied from sub-nm to ?1 nm. The suitability of using an Al wetting layer for initiation of the ALD Al{sub 2}O{sub 3} tunnel barrier was investigated with ellipsometry, atomic force microscopy, and electrical transport measurements. With optimized processing conditions, leak-free SIS tunnel junctions were obtained, demonstrating the viability of this integrated ALD-UHV sputtering system for the fabrication of tunnel junctions and devices comprised of metal-dielectric-metal multilayers.

  9. MHK Projects/Fort Ross North | Open Energy Information

    Open Energy Info (EERE)

    Capacity (MW) 5 Main Overseeing Organization Sonoma Co Water Agency CA Project Licensing Environmental Monitoring and Mitigation Efforts See Tethys << Return to the MHK database...

  10. MHK Projects/Del Mar Landing | Open Energy Information

    Open Energy Info (EERE)

    Capacity (MW) 5 Main Overseeing Organization Sonoma Co Water Agency CA Project Licensing Environmental Monitoring and Mitigation Efforts See Tethys << Return to the MHK database...

  11. Design procedures for coal mine tunnels. Open file report 1 Oct 79-31 Dec 82 (final)

    SciTech Connect (OSTI)

    Bieniawski, Z.T.

    1983-03-31

    Although coal mine tunnels such as the main haulageways or roadways are the lifelines of coal mines, little attention has been paid to them in the United States in terms of preconstruction planning and design. This report summarizes the results of a 3-year research project aimed at improving the design procedures for coal mine tunnels. A new design approach was developed for this purpose and roof-support design charts were prepared for mine tunnels and their intersections. Analytical studies, 'base friction' model experiments, and in situ rock stress measurements were performed during this research.

  12. 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.

  13. Water Power

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

    ...016-03-01T17:12:00+00:00 March 1st, 2016|News, News & Events, Water Power, Workshops|0 Comments Read More Wave energy distribution example Permalink Gallery Sandia releases 2nd ...

  14. A Historical Evaluation of the U12n Tunnel, Nevada national Security Site, Nye County, Nevada Part 2 of 2

    SciTech Connect (OSTI)

    Drollinger, Harold; Jones, Robert C; Bullard, Thomas F; Ashbaugh, Laurence J; Griffin, Wayne R

    2011-06-01

    This report presents a historical evaluation of the U12n Tunnel on the Nevada National Security Site (NNSS) in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12n Tunnel was one of a series of tunnels used for underground nuclear weapons effects tests in Rainier and Aqueduct Mesas. A total of 22 nuclear tests were conducted in the U12n Tunnel from 1967 to 1992. These tests include Midi Mist, Hudson Seal, Diana Mist, Misty North, Husky Ace, Ming Blade, Hybla Fair, Mighty Epic, Diablo Hawk, Miners Iron, Huron Landing, Diamond Ace, Mini Jade, Tomme/Midnight Zephyr, Misty Rain, Mill Yard, Diamond Beech, Middle Note, Misty Echo, Mineral Quarry, Randsburg, and Hunters Trophy. DTRA sponsored all tests except Tomme and Randsburg which were sponsored by the Lawrence Livermore National Laboratory. Midnight Zephyr, sponsored by DTRA, was an add on experiment to the Tomme test. Eleven high explosive tests were also conducted in the tunnel and included a Stemming Plan Test, the Pre-Mill Yard test, the two seismic Non-Proliferation Experiment tests, and seven Dipole Hail tests. The U12n Tunnel complex is composed of the portal and mesa areas, encompassing a total area of approximately 600 acres (240 hectares). Major modifications to the landscape have resulted from four principal activities. These are road construction and maintenance, mining activities related to development of the tunnel complex, site preparation for activities related to testing, and construction of retention ponds. A total of 202 cultural features were recorded for the portal and mesa areas. At the portal area, features relate to the mining, construction, testing, and general everyday operational support activities within the tunnel. These include concrete foundations for buildings, ventilation

  15. A Historical Evaluation of the U12n Tunnel, Nevada National Security Site, Nye County, Nevada Part 1

    SciTech Connect (OSTI)

    Drollinger, Harold; Jones, Robert C; Bullard, Thomas F; Ashbaugh, Laurence J; Griffin, Wayne R

    2011-06-01

    This report presents a historical evaluation of the U12n Tunnel on the Nevada National Security Site (NNSS) in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12n Tunnel was one of a series of tunnels used for underground nuclear weapons effects tests in Rainier and Aqueduct Mesas. A total of 22 nuclear tests were conducted in the U12n Tunnel from 1967 to 1992. These tests include Midi Mist, Hudson Seal, Diana Mist, Misty North, Husky Ace, Ming Blade, Hybla Fair, Mighty Epic, Diablo Hawk, Miners Iron, Huron Landing, Diamond Ace, Mini Jade, Tomme/Midnight Zephyr, Misty Rain, Mill Yard, Diamond Beech, Middle Note, Misty Echo, Mineral Quarry, Randsburg, and Hunters Trophy. DTRA sponsored all tests except Tomme and Randsburg which were sponsored by the Lawrence Livermore National Laboratory. Midnight Zephyr, sponsored by DTRA, was an add on experiment to the Tomme test. Eleven high explosive tests were also conducted in the tunnel and included a Stemming Plan Test, the Pre-Mill Yard test, the two seismic Non-Proliferation Experiment tests, and seven Dipole Hail tests. The U12n Tunnel complex is composed of the portal and mesa areas, encompassing a total area of approximately 600 acres (240 hectares). Major modifications to the landscape have resulted from four principal activities. These are road construction and maintenance, mining activities related to development of the tunnel complex, site preparation for activities related to testing, and construction of retention ponds. A total of 202 cultural features were recorded for the portal and mesa areas. At the portal area, features relate to the mining, construction, testing, and general everyday operational support activities within the tunnel. These include concrete foundations for buildings, ventilation

  16. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 6 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  17. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 3 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  18. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 5 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  19. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 4 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  20. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 2 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  1. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 1 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  2. Macroscopic quantum tunneling in small Josephson junctions in a magnetic field.

    SciTech Connect (OSTI)

    Ovchinnikov, Yu. N.; Barone, A.; Varlamov, A. A.; Materials Science Division; Max-Planck Inst. for Physics of Complex Systems; Landau Inst. Theoretical Physics; Univ. di Napoli Federico II; Coherentia-INFM, CNR

    2007-01-01

    We study the phenomenon of macroscopic quantum tunneling (MQT) in small Josephson junctions (JJ) with an externally applied magnetic field. The latter results in the appearance of the Fraunhofer type modulation of the current density along the barrier. The problem of MQT for a pointlike JJ is reduced to the motion of the quantum particle in the washboard potential. In the case of a finite size JJ under consideration, this problem corresponds to a MQT in a potential which itself, besides the phase, depends on space variables. The general expression for the crossover temperature To between thermally activated and macroscopic quantum tunneling regimes and the escaping time {tau}{sub esc} have been calculated.

  3. DEVELOPMENT AND APPLICATION OF A FAST-RUNNING TOOL TO CHARACTERIZE SHOCK DAMAGE WITHIN TUNNEL STRUCTURES

    SciTech Connect (OSTI)

    Glascoe, L; Morris, J; Glenn, L; Krnjajic, M

    2009-03-31

    Successful but time-intensive use of high-fidelity computational capabilities for shock loading events and resultant effects on and within enclosed structures, e.g., tunnels, has led to an interest in developing more expedient methods of analysis. While several tools are currently available for the general study of the failure of structures under dynamic shock loads at a distance, presented are a pair of statistics- and physics-based tools that can be used to differentiate different types of damage (e.g., breach versus yield) as well as quantify the amount of damage within tunnels for loads close-in and with standoff. Use of such faster running tools allows for scoping and planning of more detailed model and test analysis and provides a way to address parametric sensitivity over a large multivariate space.

  4. 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.

  5. Bohm-Aharonov and Kondo effects on tunneling currents in a mesoscopic ring

    SciTech Connect (OSTI)

    Davidovich, M.A.; Anda, E.V.; Chiappe, G.

    1997-03-01

    We present an analysis of the Kondo effect on the Bohm-Aharonov oscillations of the tunneling currents in a mesoscopic ring with a quantum dot inserted in one of its arms. The system is described by an Anderson-impurity tight-binding Hamiltonian where the electron-electron interaction is restricted to the dot. The currents are obtained using nonequilibrium Green functions calculated through a cumulant diagrammatic expansion in the chain approximation. It is shown that at low temperature, even with the system out of resonance, the Kondo peak provides a channel for the electron to tunnel through the dot, giving rise to the Bohm-Aharonov oscillations of the current. At high temperature these oscillations are important only if the dot level is aligned to the Fermi level, when the resonance condition is satisfied. {copyright} {ital 1997} {ital The American Physical Society}

  6. Detecting the tunneling rates for strongly interacting fermions on optical lattices

    SciTech Connect (OSTI)

    Anfossi, Alberto

    2010-04-15

    Strongly interacting fermionic atoms on optical lattices are studied through a Hubbard-like model Hamiltonian, in which tunneling rates of atoms and molecules between neighboring sites are assumed to be different. In the limit of large on-site repulsion U, the model is shown to reproduce the t-J Hamiltonian, in which the J coefficient of the Heisenberg term depends on the particle-assisted tunneling rate g: explicitly, J=4g{sup 2}/U. At half-filling, g drives a crossover from a Brinkman-Rice paramagnetic insulator of fully localized atoms (g=0) to the antiferromagnetic Mott insulator of the standard Hubbard case (g=t). This is observed already in the number of doubly occupied sites under the intermediate coupling regime, thus providing a criterion for extracting from measurements the effective value of g.

  7. Tunneling electron induced molecular electroluminescence from individual porphyrin J-aggregates

    SciTech Connect (OSTI)

    Meng, Qiushi; Zhang, Chao; Zhang, Yang E-mail: zcdong@ustc.edu.cn; Zhang, Yao; Liao, Yuan; Dong, Zhenchao E-mail: zcdong@ustc.edu.cn

    2015-07-27

    We investigate molecular electroluminescence from individual tubular porphyrin J-aggregates on Au(111) by tunneling electron excitations in an ultrahigh-vacuum scanning tunneling microscope (STM). High-resolution STM images suggest a spiral tubular structure for the porphyrin J-aggregate with highly ordered “brickwork”-like arrangements. Such aggregated nanotube is found to behave like a self-decoupled molecular architecture and shows red-shifted electroluminescence characteristics of J-aggregates originated from the delocalized excitons. The positions of the emission peaks are found to shift slightly depending on the excitation sites, which, together with the changes in the observed spectral profiles with vibronic progressions, suggest a limited exciton coherence number within several molecules. The J-aggregate electroluminescence is also found unipolar, occurring only at negative sample voltages, which is presumably related to the junction asymmetry in the context of molecular excitations via the carrier injection mechanism.

  8. Vector spin modeling for magnetic tunnel junctions with voltage dependent effects

    SciTech Connect (OSTI)

    Manipatruni, Sasikanth Nikonov, Dmitri E.; Young, Ian A.

    2014-05-07

    Integration and co-design of CMOS and spin transfer devices requires accurate vector spin conduction modeling of magnetic tunnel junction (MTJ) devices. A physically realistic model of the MTJ should comprehend the spin torque dynamics of nanomagnet interacting with an injected vector spin current and the voltage dependent spin torque. Vector spin modeling allows for calculation of 3 component spin currents and potentials along with the charge currents/potentials in non-collinear magnetic systems. Here, we show 4-component vector spin conduction modeling of magnetic tunnel junction devices coupled with spin transfer torque in the nanomagnet. Nanomagnet dynamics, voltage dependent spin transport, and thermal noise are comprehended in a self-consistent fashion. We show comparison of the model with experimental magnetoresistance (MR) of MTJs and voltage degradation of MR with voltage. Proposed model enables MTJ circuit design that comprehends voltage dependent spin torque effects, switching error rates, spin degradation, and back hopping effects.

  9. Improved tunneling magnetoresistance at low temperature in manganite junctions grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Werner, R.; Kleiner, R.; Koelle, D.; Petrov, A. Yu.; Davidson, B. A.; Mino, L. Alvarez

    2011-04-18

    We report resistance versus magnetic field measurements for a La{sub 0.65}Sr{sub 0.35}MnO{sub 3}/SrTiO{sub 3}/La{sub 0.65}Sr{sub 0.35}MnO{sub 3} tunnel junction grown by molecular-beam epitaxy, that show a large field window of extremely high tunneling magnetoresistance (TMR) at low temperature. Scanning the in-plane applied field orientation through 360 deg., the TMR shows fourfold symmetry, i.e., biaxial anisotropy, aligned with the crystalline axis but not the junction geometrical long axis. The TMR reaches {approx}1900% at 4 K, corresponding to an interfacial spin polarization of >95% assuming identical interfaces. These results show that uniaxial anisotropy is not necessary for large TMR, and lay the groundwork for future improvements in TMR in manganite junctions.

  10. Perpendicular magnetic tunnel junctions with double barrier and single or synthetic antiferromagnetic storage layer

    SciTech Connect (OSTI)

    Cuchet, La; Rodmacq, Bernard; Auffret, Stphane; Sousa, Ricardo C.; Prejbeanu, Ioan L.; Dieny, Bernard

    2015-06-21

    The magnetic properties of double tunnel junctions with perpendicular anisotropy were investigated. Two synthetic antiferromagnetic references are used, while the middle storage magnetic layer can be either a single ferromagnetic or a synthetic antiferromagnetic FeCoB-based layer, with a critical thickness as large as 3.0?nm. Among the different achievable magnetic configurations in zero field, those with either antiparallel references, and single ferromagnetic storage layer, or parallel references, and synthetic antiferromagnetic storage layer, are of particular interest since they allow increasing the efficiency of spin transfer torque writing and the thermal stability of the stored information as compared to single tunnel junctions. The latter configuration can be preferred when stray fields would favour a parallel orientation of the reference layers. In this case, the synthetic antiferromagnetic storage layer is also less sensitive to residual stray fields.