National Library of Energy BETA

Sample records for resulting cascading effect

  1. Including the Effects of Electronic Excitations and Electron-Phonon Coupling in Cascade Simulations

    SciTech Connect (OSTI)

    Duffy, Dorothy |

    2008-07-01

    Radiation damage has traditionally been modeled using cascade simulations however such simulations generally neglect the effects of electron-ion interactions, which may be significant in high energy cascades. A model has been developed which includes the effects of electronic stopping and electron-phonon coupling in Molecular Dynamics simulations by means of an inhomogeneous Langevin thermostat. The energy lost by the atoms to electronic excitations is gained by the electronic system and the energy evolution of the electronic system is modeled by the heat diffusion equation. Energy is exchanged between the electronic system and the atoms in the Molecular Dynamics simulation by means of a Langevin thermostat, the temperature of which is the local electronic temperature. The model is applied to a 10 keV cascade simulation for Fe. (authors)

  2. Effects of the density of collision cascades: Separating contributions from dynamic annealing and energy spikes

    SciTech Connect (OSTI)

    Titov, A I; Karaseov, P A; Azarov, A Y; Kucheyev, S O

    2008-08-13

    We present a quantitative model for the efficiency of the molecular effect in damage buildup in semiconductors. Our model takes into account only one mechanism of the cascade density dependence: nonlinear energy spikes. In our three-dimensional analysis, the volume of each individual collision cascade is divided into small cubic cells, and the number of cells that have an average density of displacements above some threshold value is calculated. We assume that such cells experience a catastrophic crystalline-to-amorphous phase transition, while defects in the cells with lower displacement densities have perfect annihilation. For the two limiting cases of heavy (500 keV/atom {sup 209}Bi) and light (40 keV/atom {sup 14}N) ion bombardment of Si, theory predictions are in good agreement with experimental data for a threshold displacement density of 4.5 at.%. For intermediate density cascades produced by small 2.1 keV/amu PF{sub n} clusters, we show that dynamic annealing processes entirely dominate cascade density effects for PF{sub 2} ions, while energy spikes begin contributing in the case of PF{sub 4} cluster bombardment.

  3. Intra Nucleon Cascade Program

    Energy Science and Technology Software Center (OSTI)

    1998-08-18

    The package consists of three programs ISABEL, EVA, and PACE-2. ISABEL and PACE-2 are part of the LAHET code. ISABEL is an intra-nucleon cascade program. The output cascades are used as directly as input files to the two evaporation programs EVA and PACE-2. EVA ignores the effect of the angular momentum of the excited nuclei on the deexcitation and also ignores the possibility of gamma emission as long as particle emission is energetically allowed. PACE-2more » takes full account of angular momentum effects including irast levels and gamma emission at all stages of the evaporation chain.« less

  4. A cascaded model of spectral distortions due to spectral response effects and pulse pileup effects in a photon-counting x-ray detector for CT

    SciTech Connect (OSTI)

    Cammin, Jochen E-mail: ktaguchi@jhmi.edu; Taguchi, Katsuyuki E-mail: ktaguchi@jhmi.edu; Xu, Jennifer; Barber, William C.; Iwanczyk, Jan S.; Hartsough, Neal E.

    2014-04-15

    Purpose: Energy discriminating, photon-counting detectors (PCDs) are an emerging technology for computed tomography (CT) with various potential benefits for clinical CT. The photon energies measured by PCDs can be distorted due to the interactions of a photon with the detector and the interaction of multiple coincident photons. These effects result in distorted recorded x-ray spectra which may lead to artifacts in reconstructed CT images and inaccuracies in tissue identification. Model-based compensation techniques have the potential to account for the distortion effects. This approach requires only a small number of parameters and is applicable to a wide range of spectra and count rates, but it needs an accurate model of the spectral distortions occurring in PCDs. The purpose of this study was to develop a model of those spectral distortions and to evaluate the model using a PCD (model DXMCT-1; DxRay, Inc., Northridge, CA) and various x-ray spectra in a wide range of count rates. Methods: The authors hypothesize that the complex phenomena of spectral distortions can be modeled by: (1) separating them into count-rate independent factors that we call the spectral response effects (SRE), and count-rate dependent factors that we call the pulse pileup effects (PPE), (2) developing separate models for SRE and PPE, and (3) cascading the SRE and PPE models into a combined SRE+PPE model that describes PCD distortions at both low and high count rates. The SRE model describes the probability distribution of the recorded spectrum, with a photo peak and a continuum tail, given the incident photon energy. Model parameters were obtained from calibration measurements with three radioisotopes and then interpolated linearly for other energies. The PPE model used was developed in the authors previous work [K. Taguchi et al., Modeling the performance of a photon counting x-ray detector for CT: Energy response and pulse pileup effects, Med. Phys. 38(2), 10891102 (2011)]. The

  5. Ideas for Effective Communication of Statistical Results

    SciTech Connect (OSTI)

    Anderson-Cook, Christine M.

    2015-03-01

    Effective presentation of statistical results to those with less statistical training, including managers and decision-makers requires planning, anticipation and thoughtful delivery. Here are several recommendations for effectively presenting statistical results.

  6. Contingency Analysis of Cascading Line Outage Events

    SciTech Connect (OSTI)

    Thomas L Baldwin; Magdy S Tawfik; Miles McQueen

    2011-03-01

    As the US power systems continue to increase in size and complexity, including the growth of smart grids, larger blackouts due to cascading outages become more likely. Grid congestion is often associated with a cascading collapse leading to a major blackout. Such a collapse is characterized by a self-sustaining sequence of line outages followed by a topology breakup of the network. This paper addresses the implementation and testing of a process for N-k contingency analysis and sequential cascading outage simulation in order to identify potential cascading modes. A modeling approach described in this paper offers a unique capability to identify initiating events that may lead to cascading outages. It predicts the development of cascading events by identifying and visualizing potential cascading tiers. The proposed approach was implemented using a 328-bus simplified SERC power system network. The results of the study indicate that initiating events and possible cascading chains may be identified, ranked and visualized. This approach may be used to improve the reliability of a transmission grid and reduce its vulnerability to cascading outages.

  7. Engineering Light: Quantum Cascade Lasers

    ScienceCinema (OSTI)

    Claire Gmachl

    2010-09-01

    Quantum cascade lasers are ideal for environmental sensing and medical diagnostic applications. Gmachl discusses how these lasers work, and their applications, including their use as chemical trace gas sensors. As examples of these applications, she briefly presents results from her field campaign at the Beijing Olympics, and ongoing campaigns in Texas, Maryland, and Ghana.

  8. Village of Cascade | Open Energy Information

    Open Energy Info (EERE)

    Village of Cascade Sector Wind energy Facility Type Community Wind Facility Status In Service Owner Village of Cascade Energy Purchaser Village of Cascade Location Cascade WI...

  9. Multiperiod quantum-cascade nanoheterostructures: Epitaxy and diagnostics

    SciTech Connect (OSTI)

    Egorov, A. Yu. Brunkov, P. N.; Nikitina, E. V.; Pirogov, E. V.; Sobolev, M. S.; Lazarenko, A. A.; Baidakova, M. V.; Kirilenko, D. A.; Konnikov, S. G.

    2014-12-15

    Advances in the production technology of multiperiod nanoheterostructures of quantum-cascade lasers with 60 cascades by molecular-beam epitaxy (MBE) on an industrial multiple-substrate MBE machine are discussed. The results obtained in studying the nanoheterostructures of quantum-cascade lasers by transmission electron microscopy, high-resolution X-ray diffraction analysis, and photoluminescence mapping are presented.

  10. Cascades Geothermal Region | Open Energy Information

    Open Energy Info (EERE)

    Cascades Geothermal Region (Redirected from Cascades) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Cascades Geothermal Region Details Areas (2) Power Plants (0)...

  11. Cascaded thermoacoustic devices

    DOE Patents [OSTI]

    Swift, Gregory W.; Backhaus, Scott N.; Gardner, David L.

    2003-12-09

    A thermoacoustic device is formed with a resonator system defining at least one region of high specific acoustic impedance in an acoustic wave within the resonator system. A plurality of thermoacoustic units are cascaded together within the region of high specific acoustic impedance, where at least one of the thermoacoustic units is a regenerator unit.

  12. Survey of tools for risk assessment of cascading outages

    SciTech Connect (OSTI)

    Papic, Milorad; Bell, Keith; Chen, Yousu; Dobson, Ian; Fonte, Louis; Haq, Enamul; Hines, Paul; Kirschen, Daniel; Luo, Xiaochuan; Miller, Stephen; Samaan, Nader A.; Vaiman, Marianna; Varghese, Matthew; Zhang, Pei

    2011-10-01

    Abstract-This paper is a result of ongoing activity carried out by Understanding, Prediction, Mitigation and Restoration of Cascading Failures Task Force under IEEE Computer Analytical Methods Subcommittee (CAMS). The task force's previous papers [1, 2] are focused on general aspects of cascading outages such as understanding, prediction, prevention and restoration from cascading failures. This is the second of two new papers, which extend this previous work to summarize the state of the art in cascading failure risk analysis methodologies and modeling tools. The first paper reviews the state of the art in methodologies for performing risk assessment of potential cascading outages [3]. This paper describes the state of the art in cascading failure modeling tools, documenting the view of experts representing utilities, universities and consulting companies. The paper is intended to constitute a valid source of information and references about presently available tools that deal with prediction of cascading failure events. This effort involves reviewing published literature and other documentation from vendors, universities and research institutions. The assessment of cascading outages risk evaluation is in continuous evolution. Investigations to gain even better understanding and identification of cascading events are the subject of several research programs underway aimed at solving the complexity of these events that electrical utilities face today. Assessing the risk of cascading failure events in planning and operation for power transmission systems require adequate mathematical tools/software.

  13. Results of an effective cable inspection program

    SciTech Connect (OSTI)

    Lenko, J.P.; Charlton, C.B.; Vollkommer, H.T. Jr.

    1995-10-01

    To provide better service to customers and to maximize the service life of distribution underground cables, a cable inspection program began in April of 1992. This inspection program covers medium voltage cable and supplements the minimum AEIC testing requirements done by manufacturers. The AEP program has resulted in preventing substandard and non-specified cables from being placed in service. This program requires manufacturers to send a two foot sample of cable from each shipping reel prior to shipment to the Electrical Laboratory for inspection. The samples are then randomly selected for inspection. Results of each inspection are reported to AEP Operating Companies within five days and are logged into a yearly accumulative data base per manufacturer. During 1993, approximately 108,000 feet of cable were returned to manufacturers which represents about 4.54% of the medium voltage cable received on the AEP System. As a result of this inspection program it appears that several cable manufacturers have improved their product or production system resulting in a cleaner cable, meeting Company and industry standards. Results of these inspections are passed on to their customers through lower costs and a more reliable distribution system. The results of this in-house inspection program are evaluated by Distribution Engineering and sent to Purchasing for their use when preparing blanket purchase orders for cable.

  14. Thermoacoustic refrigerators and engines comprising cascading...

    Office of Scientific and Technical Information (OSTI)

    Thermoacoustic refrigerators and engines comprising cascading stirling thermodynamic units Title: Thermoacoustic refrigerators and engines comprising cascading stirling ...

  15. Building America Whole-House Solutions for Existing Homes: Cascade

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

    Apartments - Deep Energy Multifamily Retrofit (Fact Sheet) | Department of Energy Building America Whole-House Solutions for Existing Homes: Cascade Apartments - Deep Energy Multifamily Retrofit (Fact Sheet) Building America Whole-House Solutions for Existing Homes: Cascade Apartments - Deep Energy Multifamily Retrofit (Fact Sheet) This project implemented energy retrofit improvements in the Cascade multifamily community, which resulted in annual energy cost savings of 22%, improved comfort

  16. Multistep cascade annihilations of dark matter and the Galactic Center excess

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

    Elor, Gilly; Rodd, Nicholas L.; Slatyer, Tracy R.

    2015-05-26

    If dark matter is embedded in a non-trivial dark sector, it may annihilate and decay to lighter dark-sector states which subsequently decay to the Standard Model. Such scenarios - with annihilation followed by cascading dark-sector decays - can explain the apparent excess GeV gamma-rays identified in the central Milky Way, while evading bounds from dark matter direct detection experiments. Each 'step' in the cascade will modify the observable signatures of dark matter annihilation and decay, shifting the resulting photons and other final state particles to lower energies and broadening their spectra. We explore, in a model-independent way, the effect ofmore » multi-step dark-sector cascades on the preferred regions of parameter space to explain the GeV excess. We find that the broadening effects of multi-step cascades can admit final states dominated by particles that would usually produce too sharply peaked photon spectra; in general, if the cascades are hierarchical (each particle decays to substantially lighter particles), the preferred mass range for the dark matter is in all cases 20-150 GeV. Decay chains that have nearly-degenerate steps, where the products are close to half the mass of the progenitor, can admit much higher DM masses. We map out the region of mass/cross-section parameter space where cascades (degenerate, hierarchical or a combination) can fit the signal, for a range of final states. In the current paper, we study multi-step cascades in the context of explaining the GeV excess, but many aspects of our results are general and can be extended to other applications.« less

  17. Multistep cascade annihilations of dark matter and the Galactic Center excess

    SciTech Connect (OSTI)

    Elor, Gilly; Rodd, Nicholas L.; Slatyer, Tracy R.

    2015-05-26

    If dark matter is embedded in a non-trivial dark sector, it may annihilate and decay to lighter dark-sector states which subsequently decay to the Standard Model. Such scenarios - with annihilation followed by cascading dark-sector decays - can explain the apparent excess GeV gamma-rays identified in the central Milky Way, while evading bounds from dark matter direct detection experiments. Each 'step' in the cascade will modify the observable signatures of dark matter annihilation and decay, shifting the resulting photons and other final state particles to lower energies and broadening their spectra. We explore, in a model-independent way, the effect of multi-step dark-sector cascades on the preferred regions of parameter space to explain the GeV excess. We find that the broadening effects of multi-step cascades can admit final states dominated by particles that would usually produce too sharply peaked photon spectra; in general, if the cascades are hierarchical (each particle decays to substantially lighter particles), the preferred mass range for the dark matter is in all cases 20-150 GeV. Decay chains that have nearly-degenerate steps, where the products are close to half the mass of the progenitor, can admit much higher DM masses. We map out the region of mass/cross-section parameter space where cascades (degenerate, hierarchical or a combination) can fit the signal, for a range of final states. In the current paper, we study multi-step cascades in the context of explaining the GeV excess, but many aspects of our results are general and can be extended to other applications.

  18. Cascade photo production at CLAS

    SciTech Connect (OSTI)

    Goetz, John; Hicks, Kenneth H.

    2014-09-01

    The famous discovery of the Omega ? in 1964 put the quark model on firm ground and since then a lot of effort has been spent on mapping out the baryonic and mesonic states. Over the following decades, many excited baryons with light quarks (up, down and strange) have been measured, but by most predictions, only a small percentage of those expected have been found. In this talk, I will discuss a newly developing technique using an (unflavored) photon beam to excite protons to doubly-strange "Cascade" (Xi) states. Advantages of such an experiment and associated difficulties will be presented, along with recent results from the CLAS detector at Jefferson Lab in Virginia.

  19. Delay time calculation for dual-wavelength quantum cascade lasers

    SciTech Connect (OSTI)

    Hamadou, A.; Lamari, S.; Thobel, J.-L.

    2013-11-28

    In this paper, we calculate the turn-on delay (t{sub th}) and buildup (Δt) times of a midinfrared quantum cascade laser operating simultaneously on two laser lines having a common upper level. The approach is based on the four-level rate equations model describing the variation of the electron number in the states and the photon number present within the cavity. We obtain simple analytical formulae for the turn-on delay and buildup times that determine the delay times and numerically apply our results to both the single and bimode states of a quantum cascade laser, in addition the effects of current injection on t{sub th} and Δt are explored.

  20. COMPACT CASCADE IMPACTS

    DOE Patents [OSTI]

    Lippmann, M.

    1964-04-01

    A cascade particle impactor capable of collecting particles and distributing them according to size is described. In addition the device is capable of collecting on a pair of slides a series of different samples so that less time is required for the changing of slides. Other features of the device are its compactness and its ruggedness making it useful under field conditions. Essentially the unit consists of a main body with a series of transverse jets discharging on a pair of parallel, spaced glass plates. The plates are capable of being moved incremental in steps to obtain the multiple samples. (AEC)

  1. Geothermal research, Oregon Cascades: Final technical report

    SciTech Connect (OSTI)

    Priest, G.R.; Black, G.L.

    1988-10-27

    Previous USDOE-funded geothermal studies have produced an extensive temperature gradient and heat flow data base for the State of Oregon. One of the important features identified as a result of these studies is a rapid transition from heat flow values on the order of 40 mW/m/sup 2/ in the Willamette Valley and Western Cascades to values of greater than or equal to100 mW/m/sup 2/ in the High Cascades and the eastern portion of the Western Cascades. These data indicate that the Cascade Range in Oregon has potential as a major geothermal province and stimulated much of the later work completed by government agencies and private industry. Additional data generated as a result of this grant and published in DOGAMI Open-File Report 0-86-2 further define the location and magnitude of this transition zone. In addition, abundant data collected from the vicinity of Breitenbush and Austin Hot Springs have permitted the formulation of relatively detailed models of these hydrothermal systems. These models are published in DOGAMI Open-File Report 0-88-5. Task 1.2 of the Deliverables section of Amendment M001 is fulfilled by DOGAMI publication GMS-48, Geologic map of the McKenzie Bridge quadrangle, Lane County, Oregon. This map was printed in October, 1988, and is part of the final submission to USDOE. 8 refs.

  2. Whistler turbulence forward vs. inverse cascade: Three-dimensional particle-in-cell simulations

    SciTech Connect (OSTI)

    Chang, Ouliang; Gary, S. Peter; Wang, Joseph

    2015-02-12

    In this study, we present the results of the first fully three-dimensional particle-in-cell simulations of decaying whistler turbulence in a magnetized, homogeneous, collisionless plasma in which both forward cascades to shorter wavelengths, and inverse cascades to longer wavelengths are allowed to proceed. For the electron beta ?e = 0.10 initial value considered here, the early-time rate of inverse cascade is very much smaller than the rate of forward cascade, so that at late times the fluctuation energy in the regime of the inverse cascade is much weaker than that in the forward cascade regime. Similarly, the wavevector anisotropy in the inverse cascade regime is much weaker than that in the forward cascade regime.

  3. Whistler turbulence forward vs. inverse cascade. Three-dimensional particle-in-cell simulations

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

    Chang, Ouliang; Gary, S. Peter; Wang, Joseph

    2015-02-12

    In this study, we present the results of the first fully three-dimensional particle-in-cell simulations of decaying whistler turbulence in a magnetized, homogeneous, collisionless plasma in which both forward cascades to shorter wavelengths, and inverse cascades to longer wavelengths are allowed to proceed. For the electron beta βe = 0.10 initial value considered here, the early-time rate of inverse cascade is very much smaller than the rate of forward cascade, so that at late times the fluctuation energy in the regime of the inverse cascade is much weaker than that in the forward cascade regime. Similarly, the wavevector anisotropy in themore » inverse cascade regime is much weaker than that in the forward cascade regime.« less

  4. Multi-stage Cascaded Stirling Refrigerator

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

    Energy Multi-stage Cascaded Stirling Refrigerator Multi-stage Cascaded Stirling Refrigerator Los Alamos National Laboratory (LANL) researchers have developed a multi-stage...

  5. Cascade Municipal Utilities | Open Energy Information

    Open Energy Info (EERE)

    cascade-util Facebook: https:www.facebook.compagesCascade-Iowa1485913095031925?refaymthomepagepanel Outage Hotline: 563-852-3614 or 563-852-3114 References: EIA Form...

  6. Cascade redox flow battery systems

    DOE Patents [OSTI]

    Horne, Craig R.; Kinoshita, Kim; Hickey, Darren B.; Sha, Jay E.; Bose, Deepak

    2014-07-22

    A reduction/oxidation ("redox") flow battery system includes a series of electrochemical cells arranged in a cascade, whereby liquid electrolyte reacts in a first electrochemical cell (or group of cells) before being directed into a second cell (or group of cells) where it reacts before being directed to subsequent cells. The cascade includes 2 to n stages, each stage having one or more electrochemical cells. During a charge reaction, electrolyte entering a first stage will have a lower state-of-charge than electrolyte entering the nth stage. In some embodiments, cell components and/or characteristics may be configured based on a state-of-charge of electrolytes expected at each cascade stage. Such engineered cascades provide redox flow battery systems with higher energy efficiency over a broader range of current density than prior art arrangements.

  7. Risk Assessment of Cascading Outages: Methodologies and Challenges

    SciTech Connect (OSTI)

    Vaiman, Marianna; Bell, Keith; Chen, Yousu; Chowdhury, Badrul; Dobson, Ian; Hines, Paul; Papic, Milorad; Miller, Stephen; Zhang, Pei

    2012-05-31

    Abstract- This paper is a result of ongoing activity carried out by Understanding, Prediction, Mitigation and Restoration of Cascading Failures Task Force under IEEE Computer Analytical Methods Subcommittee (CAMS). The task force's previous papers are focused on general aspects of cascading outages such as understanding, prediction, prevention and restoration from cascading failures. This is the first of two new papers, which extend this previous work to summarize the state of the art in cascading failure risk analysis methodologies and modeling tools. This paper is intended to be a reference document to summarize the state of the art in the methodologies for performing risk assessment of cascading outages caused by some initiating event(s). A risk assessment should cover the entire potential chain of cascades starting with the initiating event(s) and ending with some final condition(s). However, this is a difficult task and heuristic approaches and approximations have been suggested. This paper discusses different approaches to this and suggests directions for future development of methodologies. The second paper summarizes the state of the art in modeling tools for risk assessment of cascading outages.

  8. Interband Cascade Photovoltaic Cells

    SciTech Connect (OSTI)

    Yang, Rui Q.; Santos, Michael B.; Johnson, Matthew B.

    2014-09-24

    In this project, we are performing basic and applied research to systematically investigate our newly proposed interband cascade (IC) photovoltaic (PV) cells [1]. These cells follow from the great success of infrared IC lasers [2-3] that pioneered the use of quantum-engineered IC structures. This quantum-engineered approach will enable PV cells to efficiently convert infrared radiation from the sun or other heat source, to electricity. Such cells will have important applications for more efficient use of solar energy, waste-heat recovery, and power beaming in combination with mid-infrared lasers. The objectives of our investigations are to: achieve extensive understanding of the fundamental aspects of the proposed PV structures, develop the necessary knowledge for making such IC PV cells, and demonstrate prototype working PV cells. This research will focus on IC PV structures and their segments for utilizing infrared radiation with wavelengths from 2 to 5 μm, a range well suited for emission by heat sources (1,000-2,000 K) that are widely available from combustion systems. The long-term goal of this project is to push PV technology to longer wavelengths, allowing for relatively low-temperature thermal sources. Our investigations address material quality, electrical and optical properties, and their interplay for the different regions of an IC PV structure. The tasks involve: design, modeling and optimization of IC PV structures, molecular beam epitaxial growth of PV structures and relevant segments, material characterization, prototype device fabrication and testing. At the end of this program, we expect to generate new cutting-edge knowledge in the design and understanding of quantum-engineered semiconductor structures, and demonstrate the concepts for IC PV devices with high conversion efficiencies.

  9. PP-39 Boise Cascade Corporation | Department of Energy

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

    Boise Cascade Corporation PP-39 Boise Cascade Corporation Presidential Permit authorizing Boise Cascade Corporation to construct, operate, and maintain electric transmission ...

  10. PP-96-1 Boise Cascade Corporation | Department of Energy

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

    1 Boise Cascade Corporation PP-96-1 Boise Cascade Corporation Presidental Permit authorizing Boise Cascade Corporation to construct, operate, and maintain electric transmission ...

  11. PP-96 Boise Cascade Corporation | Department of Energy

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

    Boise Cascade Corporation PP-96 Boise Cascade Corporation Presidental Permit authorizing Boise Cascade Corporation to construct, operate, and maintain electric transmission ...

  12. Cascaded target normal sheath acceleration

    SciTech Connect (OSTI)

    Wang, W. P.; Shen, B. F.; Zhang, X. M.; Wang, X. F.; Xu, J. C.; Zhao, X. Y.; Yu, Y. H.; Yi, L. Q.; Shi, Y.; Zhang, L. G.; Xu, T. J.; Xu, Z. Z.

    2013-11-15

    A cascaded target normal sheath acceleration (TNSA) scheme is proposed to simultaneously increase energy and improve energy spread of a laser-produced mono-energetic proton beam. An optimum condition that uses the maximum sheath field to accelerate the center of the proton beam is theoretically found and verified by two-dimensional particle-in-cell simulations. An initial 10 MeV proton beam is accelerated to 21 MeV with energy spread decreased from 5% to 2% under the optimum condition during the process of the cascaded TNSA. The scheme opens a way to scale proton energy lineally with laser energy.

  13. Nanowire terahertz quantum cascade lasers

    SciTech Connect (OSTI)

    Grange, Thomas

    2014-10-06

    Quantum cascade lasers made of nanowire axial heterostructures are proposed. The dissipative quantum dynamics of their carriers is theoretically investigated using non-equilibrium Green functions. Their transport and gain properties are calculated for varying nanowire thickness, from the classical-wire regime to the quantum-wire regime. Our calculation shows that the lateral quantum confinement provided by the nanowires allows an increase of the maximum operation temperature and a strong reduction of the current density threshold compared to conventional terahertz quantum cascade lasers.

  14. Risk Assessment of Cascading Outages: Part I - Overview of Methodologies

    SciTech Connect (OSTI)

    Vaiman, Marianna; Bell, Keith; Chen, Yousu; Chowdhury, Badrul; Dobson, Ian; Hines, Paul; Papic, Milorad; Miller, Stephen; Zhang, Pei

    2011-07-31

    This paper is a result of ongoing activity carried out by Understanding, Prediction, Mitigation and Restoration of Cascading Failures Task Force under IEEE Computer Analytical Methods Subcommittee (CAMS). The task force's previous papers are focused on general aspects of cascading outages such as understanding, prediction, prevention and restoration from cascading failures. This is the first of two new papers, which will extend this previous work to summarize the state of the art in cascading failure risk analysis methodologies and modeling tools. This paper is intended to be a reference document to summarize the state of the art in the methodologies for performing risk assessment of cascading outages caused by some initiating event(s). A risk assessment should cover the entire potential chain of cascades starting with the initiating event(s) and ending with some final condition(s). However, this is a difficult task and heuristic approaches and approximations have been suggested. This paper discusses diffeent approaches to this and suggests directions for future development of methodologies.

  15. Performance of the biose cascade-INEL manufactured solar home

    SciTech Connect (OSTI)

    Lau, A S; Liebelt, K H; Scofield, M P; Shinn, N R

    1980-01-01

    Two manufactured active solar homes using air collectors and rock storage were designed, bult and are being tested. The cooperative, DOE-funded project involves. Boise Cascade Corporation and the Idaho National Engineering Laboratory (INEL). The two primary goals of the project are to develop an active solar heating system that is cost-effective now, and to provide significant market penetration through the involvement of Boise Cascade, a major manufacturer of factory built houses. A brief discussion of the houses and solar systems is included, with more detailed discussion of the desktop-computer based data acquisition system and initial performance results. The 1979 cooling season data indicated a need for modifications to achieve adequate cooling system performance. Data from the heating season showed good agreement with calculations, especially the house heat loss coefficient. However, solar heating fractions were lower than predicted and an examination of the collector operating efficiency showed the collector losses to be approximately three times higher than predicted. Tests are underway to better understand the large collection losses. Comparison of the performance data and f-chart predictions shows significant differences, with predicted solar fractions being lower than actual. The solar domestic hot water preheating system performed reasonably well, with significant thermal losses noticed from the auxiliary hot water heater. Recommendations are made for the design of solar air-heating systems.

  16. Fast terahertz imaging using a quantum cascade amplifier

    SciTech Connect (OSTI)

    Ren, Yuan Wallis, Robert; Jessop, David Stephen; Degl'Innocenti, Riccardo; Klimont, Adam; Beere, Harvey E.; Ritchie, David A.

    2015-07-06

    A terahertz (THz) imaging scheme based on the effect of self-mixing in a 2.9 THz quantum cascade (QC) amplifier has been demonstrated. By coupling an antireflective-coated silicon lens to the facet of a QC laser, with no external optical feedback, the laser mirror losses are enhanced to fully suppress lasing action, creating a THz QC amplifier. The addition of reflection from an external target to the amplifier creates enough optical feedback to initiate lasing action and the resulting emission enhances photon-assisted transport, which in turn reduces the voltage across the device. At the peak gain point, the maximum photon density coupled back leads to a prominent self-mixing effect in the QC amplifier, leading to a high sensitivity, with a signal to noise ratio up to 55 dB, along with a fast data acquisition speed of 20 000 points per second.

  17. Geothermal Literature Review At Cascades Region (Ingebritsen...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Geothermal Literature Review At Cascades Region (Ingebritsen & Mariner, 2010) Exploration Activity Details...

  18. PULSAR PAIR CASCADES IN A DISTORTED MAGNETIC DIPOLE FIELD

    SciTech Connect (OSTI)

    Harding, Alice K.; Muslimov, Alex G.

    2011-01-01

    We investigate the effect of a distorted neutron star dipole magnetic field on pulsar pair cascade multiplicity and pair death lines. Using a simple model for a distorted dipole field that produces an offset polar cap (PC), we derive the accelerating electric field above the PC in space-charge-limited flow. We find that even a modest azimuthally asymmetric distortion can significantly increase the accelerating electric field on one side of the PC and, combined with a smaller field line radius of curvature, leads to larger pair multiplicity. The death line for producing pairs by curvature radiation moves downward in the P- P-dot diagram, allowing high pair multiplicities in a larger percentage of the radio pulsar population. These results could have important implications for the radio pulsar population, high energy pulsed emission, and the pulsar contribution to cosmic ray positrons.

  19. Air exchange effectiveness in office buildings: Measurement techniques and results

    SciTech Connect (OSTI)

    Fisk, W.J.; Faulkner, D.

    1992-07-01

    We define two air exchange effectiveness parameters which indicate the extent of short circuiting, mixing, or displacement air flow in an entire building, the air diffusion effectiveness which indicates the air flow pattern locally, and the normalized local age of air. After describing two tracer gas procedures for measuring these parameters, we discuss assumptions inherent in the data analysis that are often violated in large office buildings. To obtain valuable data, careful selection of buildings for measurements and assessments to determine if operating conditions are reasonably consistent with the assumptions are necessary. Multiple factors, in addition to the air flow pattern in the occupied space, can affect measurement results, consequently, the interpretation of measurements is not straightforward. We summarize the results of measurements in several office buildings and in a research laboratory. Almost all measurements indicate that the extent of both short circuiting and displacement flow is small. A moderate amount of short circuiting is evident from a few measurements in rooms with heated supply air. Ages of air and their reciprocals (local ventilation rates) often vary substantially between rooms, probably because of room-to-room variation in the rate of air supply. For future research, we suggest assessments of measurement accuracy, development of measurement approaches that may be practically applied for a broader range of buildings, and a greater focus on pollutant removal efficiencies.

  20. Crossover from localized to cascade relaxations in metallic glasses

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

    Fan, Yue; Iwashita, Takuya; Egami, Takeshi

    2015-07-21

    Thermally activated deformation is investigated in two metallic glass systems with different cooling histories. By probing the atomic displacements and stress changes on the potential energy landscape, two deformation modes, a localized process and cascade process, have observed. The localized deformation involves fewer than 30 atoms and appears in both systems, and its size is invariant with cooling history. However, the cascade deformation is more frequently observed in the fast quenched system than in the slowly quenched system. As a result, the origin of the cascade process in the fast quenched system is attributed to the higher density of localmore » minima on the underlying potential energy landscape.« less

  1. An Estimator of Propagation of Cascading Failure

    SciTech Connect (OSTI)

    Dobson, Ian; Wierzbicki, Kevin; Carreras, Benjamin A; Lynch, Vickie E; Newman, David E

    2006-01-01

    The authors suggest a statistical estimator to measure the extent to which failures propagate in cascading failures such as large blackouts.

  2. Congestion and cascades in payment systems.

    SciTech Connect (OSTI)

    Glass, Robert John, Jr.; Beyeler, Walter Eugene; Soramaki, Kimmo; Bech, Morten Linnemann

    2006-06-01

    We develop a parsimonious model of the interbank payment system to study congestion and the role of liquidity markets in alleviating congestion. The model incorporates an endogenous instruction arrival process, scale-free topology of payments between banks, fixed total liquidity that limits banks' capacity to process arriving instructions, and a global market that distributes liquidity. We find that at low liquidity, the system becomes congested and payment settlement loses correlation with payment instruction arrival, becoming coupled across the network. The onset of congestion is evidently related to the relative values of three characteristic times: the time for banks' net position to return to zero, the time for banks to exhaust their liquidity endowments, and the liquidity market relaxation time. In the congested regime, settlement takes place in cascades having a characteristic size. A global liquidity market substantially diminishes congestion, requiring only a small fraction of the payment-induced liquidity flow to achieve strong beneficial effects.

  3. Counterintuitive MCNPX Results for Scintillator Surface Roughness Effect

    SciTech Connect (OSTI)

    2012-08-12

    We have reported on our recent MCNPX simulation results of energy deposition for a group of 8 scintillation detectors, coupled with various rough surface patterns. The MCNPX results generally favored the detectors with various rough surface patterns. The observed MCNPX results are not fully explained by this work.

  4. Multilevel cascade voltage source inverter with seperate DC sources...

    Office of Scientific and Technical Information (OSTI)

    Multilevel cascade voltage source inverter with seperate DC sources Citation Details In-Document Search Title: Multilevel cascade voltage source inverter with seperate DC sources ...

  5. Multilevel cascade voltage source inverter with seperate DC sources...

    Office of Scientific and Technical Information (OSTI)

    Multilevel cascade voltage source inverter with seperate DC sources Citation Details In-Document Search Title: Multilevel cascade voltage source inverter with seperate DC sources A ...

  6. Building America Whole-House Solutions for Existing Homes: Cascade...

    Energy Savers [EERE]

    Homes: Cascade Apartments - Deep Energy Multifamily Retrofit (Fact Sheet) Building America Whole-House Solutions for Existing Homes: Cascade Apartments - Deep Energy Multifamily...

  7. Comparison of binary collision approximation and molecular dynamics for displacement cascades in GaAs.

    SciTech Connect (OSTI)

    Foiles, Stephen Martin

    2011-10-01

    The predictions of binary collision approximation (BCA) and molecular dynamics (MD) simulations of displacement cascades in GaAs are compared. There are three issues addressed in this work. The first is the optimal choice of the effective displacement threshold to use in the BCA calculations to obtain the best agreement with MD results. Second, the spatial correlations of point defects are compared. This is related to the level of clustering that occurs for different types of radiation. Finally, the size and structure of amorphous zones seen in the MD simulations is summarized. BCA simulations are not able to predict the formation of amorphous material.

  8. Cray to Install Cascade System at NERSC

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

    Cray to Install Cascade System at NERSC Cray to Install Cascade System at NERSC June 27, 2012 by Richard Gerber Cray will install a next-generation supercomputer code-named "Cascade" and a next-generation Cray Sonexion storage system at NERSC. Read the press release. Subscribe via RSS Subscribe Browse by Date August 2016 June 2016 May 2016 April 2016 January 2016 December 2015 November 2015 October 2015 September 2015 August 2015 July 2015 April 2015 March 2015 January 2015 December

  9. Generalized Modeling of Enrichment Cascades That Include Minor Isotopes

    SciTech Connect (OSTI)

    Weber, Charles F

    2012-01-01

    The monitoring of enrichment operations may require innovative analysis to allow for imperfect or missing data. The presence of minor isotopes may help or hurt - they can complicate a calculation or provide additional data to corroborate a calculation. However, they must be considered in a rigorous analysis, especially in cases involving reuse. This study considers matched-abundanceratio cascades that involve at least three isotopes and allows generalized input that does not require all feed assays or the enrichment factor to be specified. Calculations are based on the equations developed for the MSTAR code but are generalized to allow input of various combinations of assays, flows, and other cascade properties. Traditional cascade models have required specification of the enrichment factor, all feed assays, and the product and waste assays of the primary enriched component. The calculation would then produce the numbers of stages in the enriching and stripping sections and the remaining assays in waste and product streams. In cases where the enrichment factor or feed assays were not known, analysis was difficult or impossible. However, if other quantities are known (e.g., additional assays in waste or product streams), a reliable calculation is still possible with the new code, but such nonstandard input may introduce additional numerical difficulties into the calculation. Thus, the minimum input requirements for a stable solution are discussed, and a sample problem with a non-unique solution is described. Both heuristic and mathematically required guidelines are given to assist the application of cascade modeling to situations involving such non-standard input. As a result, this work provides both a calculational tool and specific guidance for evaluation of enrichment cascades in which traditional input data are either flawed or unknown. It is useful for cases involving minor isotopes, especially if the minor isotope assays are desired (or required) to be

  10. Canby Cascaded Geothermal Project Phase 1 Feasibility

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

    Peer Review Canby Cascaded Geothermal Project Phase 1 Feasibility Principal Investigator , Dale Merrick Presenter Name: Dale Merrick Organization: Modoc Contracting Track Name: Low Temperature Geothermal April, 2013 This presentation does not contain any proprietary confidential, or otherwise restricted information. 2 | US DOE Geothermal Program eere.energy.gov Overview - The Canby Project, a community-based cascaded geothermal development project, intends to generate geothermal power in

  11. Scattering assisted injection based injectorless mid infrared quantum cascade laser

    SciTech Connect (OSTI)

    Singh, Siddharth Kamoua, Ridha

    2014-06-07

    An injectorless five-well mid infrared quantum cascade laser is analyzed which relies on phonon scattering injection in contrast to resonant tunneling injection, which has been previously used for injectorless designs. A Monte Carlo based self-consistent electron and photon transport simulator is used to analyze the performance of the analyzed design and compare it to existing injectorless designs. The simulation results show that the analyzed design could greatly enhance the optical gain and the characteristic temperatures of injectorless quantum cascade lasers (QCLs) which have typically been hindered by low characteristic temperatures and significant temperature related performance degradation. Simulations of the analyzed device predict threshold current densities of 0.85?kA/cm{sup 2} and 1.95?kA/cm{sup 2} at 77?K and 300?K, respectively, which are comparable to the threshold current densities of conventional injector based QCLs.

  12. Molecular dynamics simulation of radiation damage cascades in diamond

    SciTech Connect (OSTI)

    Buchan, J. T.; Robinson, M.; Christie, H. J.; Roach, D. L.; Ross, D. K.; Marks, N. A.

    2015-06-28

    Radiation damage cascades in diamond are studied by molecular dynamics simulations employing the Environment Dependent Interaction Potential for carbon. Primary knock-on atom (PKA) energies up to 2.5 keV are considered and a uniformly distributed set of 25 initial PKA directions provide robust statistics. The simulations reveal the atomistic origins of radiation-resistance in diamond and provide a comprehensive computational analysis of cascade evolution and dynamics. As for the case of graphite, the atomic trajectories are found to have a fractal-like character, thermal spikes are absent and only isolated point defects are generated. Quantitative analysis shows that the instantaneous maximum kinetic energy decays exponentially with time, and that the timescale of the ballistic phase has a power-law dependence on PKA energy. Defect recombination is efficient and independent of PKA energy, with only 50% of displacements resulting in defects, superior to graphite where the same quantity is nearly 75%.

  13. Cascaded Microinverter PV System for Reduced Cost

    SciTech Connect (OSTI)

    Bellus, Daniel R.; Ely, Jeffrey A.

    2013-04-29

    In this project, a team led by Delphi will develop and demonstrate a novel cascaded photovoltaic (PV) inverter architecture using advanced components. This approach will reduce the cost and improve the performance of medium and large-sized PV systems. The overall project objective is to develop, build, and test a modular 11-level cascaded three-phase inverter building block for photovoltaic applications and to develop and analyze the associated commercialization plan. The system will be designed to utilize photovoltaic panels and will supply power to the electric grid at 208 VAC, 60 Hz 3-phase. With the proposed topology, three inverters, each with an embedded controller, will monitor and control each of the cascade sections, reducing costs associated with extra control boards. This report details the final disposition on this project.

  14. Extended and quasi-continuous tuning of quantum cascade lasers using superstructure gratings and integrated heaters

    SciTech Connect (OSTI)

    Bidaux, Yves; Bismuto, Alfredo Tardy, Camille; Terazzi, Romain; Gresch, Tobias; Blaser, Stéphane; Muller, Antoine; Faist, Jerome

    2015-11-30

    In this work, we demonstrate broad electrical tuning of quantum cascade lasers at 9.25 μm, 8.5 μm, and 4.4 μm in continuous wave operation using Vernier-effect distributed Bragg reflectors based on superstructure gratings. Integrated micro-heaters allow to switch from one Vernier channel to the other, while predictable and mode-hop free tuning can be obtained in each channel modulating the laser current with a side mode suppression ratio as high as 30 dB. The resulting device behaves effectively as a switchable multicolour tunable source. Tuning up to 6.5% of the central wavelength is observed. To prove the importance of the developed devices for high resolution molecular spectroscopy, a N{sub 2}O absorption spectrum has been measured.

  15. Field Mapping At Cascades Region (Ingebritsen & Mariner, 2010...

    Open Energy Info (EERE)

    to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Field Mapping At Cascades Region (Ingebritsen & Mariner, 2010) Exploration Activity Details...

  16. Data Acquisition-Manipulation At Cascades Region (Ingebritsen...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Data Acquisition-Manipulation At Cascades Region (Ingebritsen & Mariner, 2010) Exploration...

  17. Geothermal Literature Review At Cascades Region (Vice, 2010)...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Geothermal Literature Review At Cascades Region (Vice, 2010) Exploration Activity Details Location...

  18. Canby Cascaded Geothermal Project Phase 1 Feasibility | Department of

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

    Energy Canby Cascaded Geothermal Project Phase 1 Feasibility Canby Cascaded Geothermal Project Phase 1 Feasibility Canby Cascaded Geothermal Project Phase 1 Feasibility presentation at the April 2013 peer review meeting held in Denver, Colorado. canby_cascaded_peer2013.pdf (561.96 KB) More Documents & Publications Rural Cooperative Geothermal Development Electric & Agriculture Silver Peak Innovative Exploration Project Advanced 3D Geophysical Imaging Technologies for Geothermal

  19. Cascade morphology transition in bcc metals

    SciTech Connect (OSTI)

    Setyawan, Wahyu; Selby, A.; Juslin, Niklas; Stoller, Roger E.; Wirth, Brian D.; Kurtz, Richard J.

    2015-06-10

    Energetic atom collisions in solids induce shockwaves with complex morphologies. In this paper, we establish the existence of a morphological transition in such cascades. The order parameter of the morphology is defined as the exponent, $b$, in the defect production curve as a function of cascade energy ($N_F$$ \\sim$$E_{MD}^b$). Response of different bcc metals can be compared in a consistent energy domain when the energy is normalized by the transition energy, $\\mu$, between the high- and the low-energy regime. Using Cr, Fe, Mo and W data, an empirical formula of $\\mu$ as a function of displacement threshold energy, $E_d$, is presented for bcc metals.

  20. Cascade Apartments: Deep Energy Multifamily Retrofit

    SciTech Connect (OSTI)

    Gordon, A.; Mattheis, L.; Kunkle, R.; Howard, L.; Lubliner, M.

    2014-02-01

    In December of 2009-10, King County Housing Authority (KCHA) implemented energy retrofit improvements in the Cascade multifamily community, located in Kent, Washington (marine climate.)This research effort involved significant coordination from stakeholders KCHA, WA State Department of Commerce, utility Puget Sound Energy, and Cascade tenants. This report focuses on the following three primary BA research questions: 1. What are the modeled energy savings using DOE low income weatherization approved TREAT software? 2. How did the modeled energy savings compare with measured energy savings from aggregate utility billing analysis? 3. What is the Savings to Investment Ratio (SIR) of the retrofit package after considering utility window incentives and KCHA capitol improvement funding.

  1. Cascade Apartments: Deep Energy Multifamily Retrofit

    SciTech Connect (OSTI)

    Gordon, A.; Mattheis, L.; Kunkle, R.; Howard, L.; Lubliner, M.

    2014-02-01

    In December of 2009-10, King County Housing Authority (KCHA) implemented energy retrofit improvements in the Cascade multifamily community, located in Kent, Washington (marine climate.)This research effort involved significant coordination from stakeholders KCHA, WA State Department of Commerce, utility Puget Sound Energy, and Cascade tenants. This report focuses on the following three primary BA research questions : 1. What are the modeled energy savings using DOE low income weatherization approved TREAT software? 2. How did the modeled energy savings compare with measured energy savings from aggregate utility billing analysis? 3. What is the Savings to Investment Ratio (SIR) of the retrofit package after considering utility window incentives and KCHA capitol improvement funding.

  2. Cascade solar cell having conductive interconnects

    DOE Patents [OSTI]

    Borden, Peter G.; Saxena, Ram R.

    1982-10-26

    Direct ohmic contact between the cells in an epitaxially grown cascade solar cell is obtained by means of conductive interconnects formed through grooves etched intermittently in the upper cell. The base of the upper cell is directly connected by the conductive interconnects to the emitter of the bottom cell. The conductive interconnects preferably terminate on a ledge formed in the base of the upper cell.

  3. Simulation of a cascaded longitudinal space charge amplifier for coherent radiation generation

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

    Halavanau, A.; Piot, P.

    2016-03-03

    Longitudinal space charge (LSC) effects are generally considered as harmful in free-electron lasers as they can seed unfavorable energy modulations that can result in density modulations with associated emittance dilution. It was pointed out, however, that such \\micro-bunching instabilities" could be potentially useful to support the generation of broadband coherent radiation. Therefore there has been an increasing interest in devising accelerator beam lines capable of controlling LSC induced density modulations. In the present paper we augment these previous investigations by combining a grid-less space charge algorithm with the popular particle-tracking program elegant. This high-fidelity model of the space charge ismore » used to benchmark conventional LSC models. We then employ the developed model to optimize the performance of a cascaded longitudinal space charge amplifier using beam parameters comparable to the ones achievable at Fermilab Accelerator Science & Technology (FAST) facility currently under commissioning at Fermilab.« less

  4. Simulation of a cascaded longitudinal space charge amplifier for broadband radiation production using a superconducting linac

    SciTech Connect (OSTI)

    Halavanau, A.; Piot, P.

    2015-10-02

    Longitudinal space charge (LSC) effects are generally considered as harmful in free-electron lasers as they can seed unfavorable energy modulations that can result in density modulations with associated emittance dilution. It was pointed out, however, that such \\micro-bunching instabilities" could be potentially useful to support the generation of broadband coherent radiation. Therefore there has been an increasing interest in devising accelerator beam lines capable of controlling LSC induced density modulations. In the present paper we augment these previous investigations by combining a grid-less space charge algorithm with the popular particle-tracking program elegant. This high-fidelity model of the space charge is used to benchmark conventional LSC models. We then employ the developed model to optimize the performance of a cascaded longitudinal space charge amplifier using beam parameters comparable to the ones achievable at Fermilab Accelerator Science & Technology (FAST) facility currently under commissioning at Fermilab

  5. Deterministic and cascadable conditional phase gate for photonic qubits

    SciTech Connect (OSTI)

    Chudzicki, Christopher; Chuang, Isaac; Shapiro, Jeffrey H.

    2014-12-04

    Previous analyses of conditional ?{sub NL}-phase gates for photonic qubits that treat crossphase modulation (XPM) in a causal, multimode, quantum field setting suggest that a large (?? rad) nonlinear phase shift is always accompanied by fidelity-degrading noise [J. H. Shapiro, Phys. Rev. A 73, 062305 (2006); J. Gea-Banacloche, Phys. Rev. A 81, 043823 (2010)]. Using an atomic V-system to model an XPM medium, we present a conditional phase gate that, for sufficiently small nonzero ?{sub NL}, has high fidelity. The gate is made cascadable by using a special measurement, principal mode projection, to exploit the quantum Zeno effect and preclude the accumulation of fidelity-degrading departures from the principal-mode Hilbert space when both control and target photons illuminate the gate. The nonlinearity of the V-system we study is too weak for this particular implementation to be practical. Nevertheless, the idea of cascading through principal mode projection is of potential use to overcome fidelity degrading noise for a wide variety of nonlinear optical primitive gates.

  6. Mobile source emission control cost-effectiveness: Issues, uncertainties, and results

    SciTech Connect (OSTI)

    Wang, M.Q.

    1994-12-01

    Emissions from mobile sources undoubtedly contribute to US urban air pollution problems. Consequently, mobile source control measures, ranging from vehicle emission standards to reducing vehicle travel, have been adopted or proposed to help attain air quality standards. To rank various mobile source control measures, various government agencies and private organizations calculate cost-effectiveness in dollars per ton of emissions reduced. Arguments for or against certain control measures are often made on the basis of the calculated cost-effectiveness. Yet, different studies may yield significantly different cost-effectiveness results, because of the various methodologies used and assumptions regarding the values of costs and emission reductions. Because of the methodological differences, the cost-effectiveness results may not be comparable between studies. Use of incomparable cost-effectiveness results may result in adoption of ineffective control measures. This paper first discusses some important methodological issues involved in cost-effectiveness calculation for mobile sources and proposes appropriate, systematic methods for dealing with these issues. Various studies have been completed recently to evaluate the cost-effectiveness of mobile source emission control measures. These studies resulted in wide variations in the cost-effectiveness for same control measures. Methodological assumptions used in each study are presented and, based on the proposed methods for cost-effectiveness calculation, adjustments are applied to the original estimates in each study to correct inappropriate methodological assumptions and to make the studies comparable. Finally, mobile source control measures are ranked on the basis of the adjusted cost-effectiveness estimates.

  7. Molecular Dynamics Simulations of Displacement Cascades in Single and Polycrystalline Zirconia

    SciTech Connect (OSTI)

    Du Jincheng

    2009-03-10

    Displacement cascades in zirconia have been studied using classical molecular dynamics simulations. Polycrystalline zirconia with nano-meter grains were created using Voronoi polyhedra construction and studied in comparison with single crystalline zirconia. The results show that displacement cascades with similar kinetic energy generated larger number of displaced atoms in polycrystalline than in the single crystal structure. The fraction of atoms with coordination number change was also higher in polycrystalline zirconia that was explained to be due to the diffusion of oxygen and relaxation at grain boundaries.

  8. Estimating Failure Propagation in Models of Cascading Blackouts

    SciTech Connect (OSTI)

    Dobson, Ian [University of Wisconsin, Madison; Carreras, Benjamin A [ORNL; Lynch, Vickie E [ORNL; Nkei, Bertrand [ORNL; Newman, David E [University of Alaska

    2005-09-01

    We compare and test statistical estimates of failure propagation in data from versions of a probabilistic model of loading-dependent cascading failure and a power systems blackout model of cascading transmission line overloads. The comparisons suggest mechanisms affecting failure propagation and are an initial step towards monitoring failure propagation from practical system data. Approximations to the probabilistic model describe the forms of probability distributions of cascade sizes.

  9. Cascade impactor and jet plate for same

    DOE Patents [OSTI]

    Dahlin, Robert S.; Farthing, William E.; Landham Jr., Edward C.

    2004-02-03

    A sampling system and method for sampling particulate matter from a high-temperature, high-pressure gas stream. A cyclone sampler for use at high temperatures and pressures, and having threadless sacrificial connectors is disclosed. Also disclosed is an improved cascade impactor including jet plates with integral spacers, and alignment features provided for aligning the jet plates with their associated collection substrates. An activated bauxite alkali collector is disclosed, and includes an alumina liner. The sampling system can be operated remotely or locally, and can be permanently installed or configured as a portable system.

  10. Duality cascade of softly broken supersymmetric theories (Journal...

    Office of Scientific and Technical Information (OSTI)

    We study the duality cascade of softly broken supersymmetric theories. We investigate the renormalization group (RG) flow of SUSY breaking terms as well as supersymmetric ...

  11. Detection and measurement of electroreflectance on quantum cascade...

    Office of Scientific and Technical Information (OSTI)

    Detection and measurement of electroreflectance on quantum cascade laser device using Fourier transform infrared microscope Citation Details In-Document Search Title: Detection and...

  12. Cascade County, Montana: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Cascade County, Montana: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 47.4688355, -111.5453228 Show Map Loading map... "minzoom":false,"mapp...

  13. Building America Whole-House Solutions for Existing Homes: Cascade...

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

    Building America Whole-House Solutions for Existing Homes: Cascade Apartments - Deep Energy Multifamily Retrofit (Fact Sheet) Building America Whole-House Solutions for Existing...

  14. Survey of Tools for Risk Assessment of Cascading Outages

    SciTech Connect (OSTI)

    Papic, Milorad; Bell, Keith; Chen, Yousu; Dobson, Ian; Fonte, Louis; Haq, Enamul; Hines, Paul; Kirschen, Daniel; Luo, Xiaochuan; Miller, Stephen; Samaan, Nader A.; Vaiman, Marianna; Varghese, Matthew; Zhang, Pei

    2011-10-17

    Cascading failure can cause large blackouts, and a variety of methods are emerging to study this challenging topic. In parts 1 and 2 of this paper, the IEEE task force on cascading failure seeks to consolidate and review the progress of the field towards methods and tools of assessing the risk of cascading failure. Part 2 summarizes and discusses the state of the art in the available cascading failure modeling tools. The discussion integrates industry and research perspectives from a variety of institutions. Strengths, weaknesses, and gaps in current approaches are indicated.

  15. Hydrothermal Heat Discharge In The Cascade Range, Northwestern...

    Open Energy Info (EERE)

    Heat Discharge In The Cascade Range, Northwestern United States Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Hydrothermal Heat Discharge In...

  16. Remote Chemical Sensing Using Quantum Cascade Lasers

    SciTech Connect (OSTI)

    Harper, Warren W.; Strasburg, Jana D.; Aker, Pam M.; Schultz, John F.

    2004-01-20

    Research done by the IR sensors team at PNNL is focused on developing advanced spectroscopic methods for detecting signatures of nuclear, chemical, biological and explosives weapons or weapons production. The sensors we develop fall into two categories: remote sensors that can be operated at distances ranging from 150 m to 10 km, and point sensors that are used for in-situ inspection and detection. FY03 has seen an explosion in FM DIAL progress with the net result being solid confirmation that FM DIAL is a technique capable of remote chemical monitoring in a wide variety of venues. For example, FM DIAL was used to detect a small plume of hydrogen sulfide, a candidate CW agent, released in the desert environment of the Hanford 200 Area site. These experiments were conducted over a range of physical conditions including outside temperatures ranging from 70 F to 105 F and turbulence conditions ranging from quiescent to chaotic. We are now rapidly developing the information needed to design prototype FM DIAL systems that are optimized for specific applications that include scenarios such as fixed position stand-off detection and mobile UAV mounted remote monitoring. Just as an example, in FY04 we will use FM DIAL to detect both in-facility and outdoor release of enriched UF6. The rapid progress in FM DIAL research made in FY03 is attributed to several advances. First, final construction of a custom-designed trailer allowed the instrument to be housed in a mobile temperature-controlled environment. This allowed the experiment to be transported to several locations so that data could be collected under a range of physical conditions. This has led to a better understanding of a variety of experimental noise sources. With this knowledge, we have been able to implement several changes in the way the FM DIAL data is collected and processed, with the net result being a drastic improvement in our confidence of analyte concentration measurement and an improvement i n the

  17. Cascades for hydrogen isotope separation using metal hydrides

    SciTech Connect (OSTI)

    Hill, F.B.; Grzetic, V.

    1982-01-01

    Designs are presented for continuous countercurrent hydrogen isotope separation cascades based on the use of metal hydrides. The cascades are made up of pressure swing adsorption (PSA) or temperature swing adsorption (TSA) stages. The designs were evolved from consideration of previously conducted studies of the separation performance of four types of PSA and TSA processes.

  18. RECONFIGURING POWER SYSTEMS TO MINIMIZE CASCADING FAILURES: MODELS AND ALGORITHMS

    SciTech Connect (OSTI)

    Bienstock, Daniel

    2014-04-11

    the main goal of this project was to develop new scientific tools, based on optimization techniques, with the purpose of controlling and modeling cascading failures of electrical power transmission systems. We have developed a high-quality tool for simulating cascading failures. The problem of how to control a cascade was addressed, with the aim of stopping the cascade with a minimum of load lost. Yet another aspect of cascade is the investigation of which events would trigger a cascade, or more appropriately the computation of the most harmful initiating event given some constraint on the severity of the event. One common feature of the cascade models described (indeed, of several of the cascade models found in the literature) is that we study thermally-induced line tripping. We have produced a study that accounts for exogenous randomness (e.g. wind and ambient temperature) that could affect the thermal behavior of a line, with a focus on controlling the power flow of the line while maintaining safe probability of line overload. This was done by means of a rigorous analysis of a stochastic version of the heat equation. we incorporated a model of randomness in the behavior of wind power output; again modeling an OPF-like problem that uses chance-constraints to maintain low probability of line overloads; this work has been continued so as to account for generator dynamics as well.

  19. PULSAR PAIR CASCADES IN MAGNETIC FIELDS WITH OFFSET POLAR CAPS

    SciTech Connect (OSTI)

    Harding, Alice K.; Muslimov, Alex G.

    2011-12-20

    Neutron star magnetic fields may have polar caps (PCs) that are offset from the dipole axis, through field-line sweepback near the light cylinder or non-symmetric currents within the star. The effects of such offsets on electron-positron pair cascades are investigated, using simple models of dipole magnetic fields with small distortions that shift the PCs by different amounts or directions. Using a Monte Carlo pair cascade simulation, we explore the changes in the pair spectrum, multiplicity, and energy flux across the PC, as well as the trends in pair flux and pair energy flux with spin-down luminosity, L{sub sd}. We also give an estimate of the distribution of heating flux from returning positrons on the PC for different offsets. We find that even modest offsets can produce significant increases in pair multiplicity, especially for pulsars that are near or beyond the pair death lines for centered PCs, primarily because of higher accelerating fields. Pair spectra cover several decades in energy, with the spectral range of millisecond pulsars (MSPs) two orders of magnitude higher than for normal pulsars, and PC offsets allow significant extension of all spectra to lower pair energies. We find that the total PC pair luminosity L{sub pair} is proportional to L{sub sd}, with L{sub pair} {approx} 10{sup -3} L{sub sd} for normal pulsars and L{sub pair} {approx} 10{sup -2} L{sub sd} for MSPs. Remarkably, the total PC heating luminosity for even large offsets increases by less than a factor of two, even though the PC area increases by much larger factors, because most of the heating occurs near the magnetic axis.

  20. LNG cascading damage study. Volume I, fracture testing report.

    SciTech Connect (OSTI)

    Petti, Jason P.; Kalan, Robert J.

    2011-12-01

    As part of the liquefied natural gas (LNG) Cascading Damage Study, a series of structural tests were conducted to investigate the thermal induced fracture of steel plate structures. The thermal stresses were achieved by applying liquid nitrogen (LN{sub 2}) onto sections of each steel plate. In addition to inducing large thermal stresses, the lowering of the steel temperature simultaneously reduced the fracture toughness. Liquid nitrogen was used as a surrogate for LNG due to safety concerns and since the temperature of LN{sub 2} is similar (-190 C) to LNG (-161 C). The use of LN{sub 2} ensured that the tests could achieve cryogenic temperatures in the range an actual vessel would encounter during a LNG spill. There were four phases to this test series. Phase I was the initial exploratory stage, which was used to develop the testing process. In the Phase II series of tests, larger plates were used and tested until fracture. The plate sizes ranged from 4 ft square pieces to 6 ft square sections with thicknesses from 1/4 inches to 3/4 inches. This phase investigated the cooling rates on larger plates and the effect of different notch geometries (stress concentrations used to initiate brittle fracture). Phase II was divided into two sections, Phase II-A and Phase II-B. Phase II-A used standard A36 steel, while Phase II-B used marine grade steels. In Phase III, the test structures were significantly larger, in the range of 12 ft by 12 ft by 3 ft high. These structures were designed with more complex geometries to include features similar to those on LNG vessels. The final test phase, Phase IV, investigated differences in the heat transfer (cooling rates) between LNG and LN{sub 2}. All of the tests conducted in this study are used in subsequent parts of the LNG Cascading Damage Study, specifically the computational analyses.

  1. A high carrier injection terahertz quantum cascade laser based on indirectly pumped scheme

    SciTech Connect (OSTI)

    Razavipour, S. G. Xu, C.; Wasilewski, Z. R.; Ban, D.; Dupont, E.; Laframboise, S. R.; Chan, C. W. I.; Hu, Q.

    2014-01-27

    A Terahertz quantum cascade laser with a rather high injection coupling strength based on an indirectly pumped scheme is designed and experimentally implemented. To effectively suppress leakage current, the chosen quantum cascade module of the device is based on a five-well GaAs/Al{sub 0.25}Ga{sub 0.75}As structure. The device lases up to 151 K with a lasing frequency of 2.67 THz. This study shows that the effect of higher energy states in carrier transport and the long-range tunnel coupling between states that belong to non-neighbouring modules have to be considered in quantum design of structures with a narrow injector barrier. Moreover, the effect of interface roughness scattering between the lasing states on threshold current is crucial.

  2. Vulnerability Assessment for Cascading Failures in Electric Power Systems

    SciTech Connect (OSTI)

    Baldick, R.; Chowdhury, Badrul; Dobson, Ian; Dong, Zhao Yang; Gou, Bei; Hawkins, David L.; Huang, Zhenyu; Joung, Manho; Kim, Janghoon; Kirschen, Daniel; Lee, Stephen; Li, Fangxing; Li, Juan; Li, Zuyi; Liu, Chen-Ching; Luo, Xiaochuan; Mili, Lamine; Miller, Stephen; Nakayama, Marvin; Papic, Milorad; Podmore, Robin; Rossmaier, John; Schneider, Kevin P.; Sun, Hongbin; Sun, Kai; Wang, David; Wu, Zhigang; Yao, Liangzhong; Zhang, Pei; Zhang, Wenjie; Zhang, Xiaoping

    2008-09-10

    Cascading failures present severe threats to power grid security, and thus vulnerability assessment of power grids is of significant importance. Focusing on analytic methods, this paper reviews the state of the art of vulnerability assessment methods in the context of cascading failures in three categories: steady-state modeling based analysis; dynamic modeling analysis; and non-traditional modeling approaches. The impact of emerging technologies including phasor technology, high-performance computing techniques, and visualization techniques on the vulnerability assessment of cascading failures is then addressed, and future research directions are presented.

  3. Additive effects of electronic and nuclear energy loss in irradiation-induced amorphization of zircon

    SciTech Connect (OSTI)

    Zarkadoula, Eva; Toulemonde, Marcel; Weber, William J.

    2015-12-29

    We used a combination of ion cascades and the unified thermal spike model to study the electronic effects from 800 keV Kr and Xe ion irradiation in zircon. We compared the damage production for four cases: (a) due to ion cascades alone, (b) due to ion cascades with the electronic energy loss activated as a friction term, (c) due to the thermal spike from the combined electronic and nuclear energy losses, and (d) due to ion cascades with electronic stopping and the electron-phonon interactions superimposed. As a result, we found that taking the electronic energy loss out as a friction term results in reduced damage, while the electronic electron-phonon interactions have additive impact on the final damage created per ion.

  4. Additive effects of electronic and nuclear energy loss in irradiation-induced amorphization of zircon

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

    Zarkadoula, Eva; Toulemonde, Marcel; Weber, William J.

    2015-12-29

    We used a combination of ion cascades and the unified thermal spike model to study the electronic effects from 800 keV Kr and Xe ion irradiation in zircon. We compared the damage production for four cases: (a) due to ion cascades alone, (b) due to ion cascades with the electronic energy loss activated as a friction term, (c) due to the thermal spike from the combined electronic and nuclear energy losses, and (d) due to ion cascades with electronic stopping and the electron-phonon interactions superimposed. As a result, we found that taking the electronic energy loss out as a frictionmore » term results in reduced damage, while the electronic electron-phonon interactions have additive impact on the final damage created per ion.« less

  5. Separations by supported liquid membrane cascades

    DOE Patents [OSTI]

    Danesi, Pier R.

    1986-01-01

    The invention describes a new separation technique which leads to multi-stage operations by the use of a series (a cascade) of alternated carrier-containing supported-liquid membranes. The membranes contain alternatively a liquid cation exchanger extractant and a liquid anion exchanger extractant (or a neutral extractant) as carrier. The membranes are spaced between alternated aqueous electrolytic solutions of different composition which alternatively provide positively charged extractable species and negatively charged (or zero charged) extractable species, of the chemical species to be separated. The alternated aqueous electrolytic solutions in addition to providing the driving force to the process, simultaneously function as a stripping solution from one type of membrane and as an extraction-promoting solution for the other type of membrane. The aqueous electrolytic solutions and the supported liquid membranes are arranged in such a way to provide a continuous process which leads to the continuous enrichment of the species which show the highest permeability coefficients. By virtue of the very high number of stages which can be arranged, even chemical species having very similar chemical behavior (and consequently very similar permeability coefficients) can be completely separated. The invention also provide a way to concentrate the separated species.

  6. Oregon Cascades Play Fairway Analysis: Faults and Heat Flow maps

    SciTech Connect (OSTI)

    Adam Brandt

    2015-11-15

    This submission includes a fault map of the Oregon Cascades and backarc, a probability map of heat flow, and a fault density probability layer. More extensive metadata can be found within each zip file.

  7. Statistical analysis of cascading failures in power grids

    SciTech Connect (OSTI)

    Chertkov, Michael; Pfitzner, Rene; Turitsyn, Konstantin

    2010-12-01

    We introduce a new microscopic model of cascading failures in transmission power grids. This model accounts for automatic response of the grid to load fluctuations that take place on the scale of minutes, when optimum power flow adjustments and load shedding controls are unavailable. We describe extreme events, caused by load fluctuations, which cause cascading failures of loads, generators and lines. Our model is quasi-static in the causal, discrete time and sequential resolution of individual failures. The model, in its simplest realization based on the Directed Current description of the power flow problem, is tested on three standard IEEE systems consisting of 30, 39 and 118 buses. Our statistical analysis suggests a straightforward classification of cascading and islanding phases in terms of the ratios between average number of removed loads, generators and links. The analysis also demonstrates sensitivity to variations in line capacities. Future research challenges in modeling and control of cascading outages over real-world power networks are discussed.

  8. Cascade-Fairwood, Washington: Energy Resources | Open Energy...

    Open Energy Info (EERE)

    You can help OpenEI by expanding it. Cascade-Fairwood is a census-designated place in King County, Washington.1 References US Census Bureau 2005 Place to 2006 CBSA...

  9. Optimization of the output and efficiency of a high power cascaded arc hydrogen plasma source

    SciTech Connect (OSTI)

    Vijvers, W. A. J.; Gils, C. A. J. van; Goedheer, W. J.; Meiden, H. J. van der; Veremiyenko, V. P.; Westerhout, J.; Lopes Cardozo, N. J.; Rooij, G. J. van; Schram, D. C.

    2008-09-15

    The operation of a cascaded arc hydrogen plasma source was experimentally investigated to provide an empirical basis for the scaling of this source to higher plasma fluxes and efficiencies. The flux and efficiency were determined as a function of the input power, discharge channel diameter, and hydrogen gas flow rate. Measurements of the pressure in the arc channel show that the flow is well described by Poiseuille flow and that the effective heavy particle temperature is approximately 0.8 eV. Interpretation of the measured I-V data in terms of a one-parameter model shows that the plasma production is proportional to the input power, to the square root of the hydrogen flow rate, and is independent of the channel diameter. The observed scaling shows that the dominant power loss mechanism inside the arc channel is one that scales with the effective volume of the plasma in the discharge channel. Measurements on the plasma output with Thomson scattering confirm the linear dependence of the plasma production on the input power. Extrapolation of these results shows that (without a magnetic field) an improvement in the plasma production by a factor of 10 over where it was in van Rooij et al. [Appl. Phys. Lett. 90, 121501 (2007)] should be possible.

  10. Principal facts and a discussion of terrain correction methods for the complete Bouguer gravity anomaly map of the Cascade Mountains, Washington

    SciTech Connect (OSTI)

    Danes, Z.F.; Phillips, W.M.

    1983-02-01

    Since 1974, the Division of Geology and Earth Resources, in conjunction with the US Department of Energy, has supported gravity studies in the Cascade Mountains of Washington State. Results of the Cascade gravity project are summarized graphically as a complete Bouguer gravity anomaly map of the Cascade Mountains, Washington (Danes and Phillips, 1983). This report provides supplementary data and documentation for the complete Bouguer gravity anomaly map. Presented are principal gravity facts, simple Bouguer and Free-air gravity anomalies, computational methods, error analysis and a discussion of terrain corrections.

  11. Saturated absorption in a rotational molecular transition at 2.5 THz using a quantum cascade laser

    SciTech Connect (OSTI)

    Consolino, L. Campa, A.; Ravaro, M.; Mazzotti, D.; Bartalini, S.; De Natale, P.; Vitiello, M. S.

    2015-01-12

    We report on the evidence of saturation effects in a rotational transition of CH{sub 3}OH around 2.5?THz, induced by a free-running continuous-wave quantum cascade laser (QCL). The QCL emission is used for direct-absorption spectroscopy experiments, allowing to study the dependence of the absorption coefficient on gas pressure and laser intensity. A saturation intensity of 25??W/mm{sup 2}, for a gas pressure of 17??bar, is measured. This result represents the initial step towards the implementation of a QCL-based high-resolution sub-Doppler THz spectroscopy, which is expected to improve by orders of magnitude the precision of THz spectrometers.

  12. Cascading metallic gratings for broadband absorption enhancement in ultrathin plasmonic solar cells

    SciTech Connect (OSTI)

    Wen, Long; Sun, Fuhe; Chen, Qin

    2014-04-14

    The incorporation of plasmonic nanostructures in the thin-film solar cells (TFSCs) is a promising route to harvest light into the nanoscale active layer. However, the light trapping scheme based on the plasmonic effects intrinsically presents narrow-band resonant enhancement of light absorption. Here we demonstrate that by cascading metal nanogratings with different sizes atop the TFSCs, broadband absorption enhancement can be realized by simultaneously exciting multiple localized surface plasmon resonances and inducing strong coupling between the plasmonic modes and photonic modes. As a proof of concept, we demonstrate of 66.5% in the photocurrent in an ultrathin amorphous silicon TFSC with two-dimensional cascaded gratings over the reference cell without gratings.

  13. Mode-locked terahertz quantum cascade laser by direct phase synchronization

    SciTech Connect (OSTI)

    Maussang, K.; Maysonnave, J.; Jukam, N.; Freeman, J. R.; Cavali, P.; Dhillon, S. S.; Tignon, J.; Khanna, S. P.; Linfield, E. H.; Davies, A. G.; Beere, H. E.; Ritchie, D. A.

    2013-12-04

    Mode-locking of a terahertz quantum cascade laser is achieved using multimode injection seeding. Contrary to standard methods that rely on gain modulation, here a fixed phase relationship is directly imprinted to the laser modes. In this work, we demonstrate the generation of 9 ps phase mode-locked pulses around 2.75 THz. A direct measurement of the emitted field phase shows that it results from the phase of the initial injection.

  14. Management Challenges in Developing Performance Assessments and Effectively Communicating Their Results - 13612

    SciTech Connect (OSTI)

    Thomas, Steve; Mahoney, Mark

    2013-07-01

    The end of the Cold War has left a legacy of approximately 37 million gallons of radioactive waste in the aging waste tanks at the Department of Energy's Savannah River Site (SRS). A robust program is in place to remove waste from these tanks, treat the waste to separate into a relatively small volume of high level waste and a large volume of low-level waste, and to actively dispose of the low-level waste on-site and close the cleaned waste tanks and associated ancillary structures. To support performance-based, risk-informed decision making, performance assessments have been developed for the low-level waste disposal facility and for the SRS Tank Farms. Although these performance assessments share many similar features, the nature of the hazards and associated containments differ. As a management team, we are challenged to effectively communicate both the similarities and differences of these performance assessments, how they should be used to support sound decision making for treatment, disposal and waste tank cleaning decisions, and in defending their respective assumptions to the regulatory community and the public but, equally important, to our own corporate decision makers and operations personnel. Effective development and defense of these performance assessments, and effective interpretation and communication of the results are key to making cost-effective, pragmatic decisions for the safe disposal of the low-level waste and stabilization and operational closure of the cleaned tanks and associated structures. This paper will focus on the importance and challenges in communicating key attributes, conclusions and operational implications within a company. (authors)

  15. Thermodynamic analysis of cascade microcryocoolers with low pressure ratios

    SciTech Connect (OSTI)

    Radebaugh, Ray

    2014-01-29

    The vapor-compression cycle for refrigeration near ambient temperature achieves high efficiency because the isenthalpic expansion of the condensed liquid is a rather efficient process. However, temperatures are limited to about 200 K with a single-stage system. Temperatures down to 77 K are possible with many stages. In the case of microcryocoolers using microcompressors, pressure ratios are usually limited to about 6 or less. As a result, even more stages are required to reach 77 K. If the microcompressors can be fabricated with low-cost wafer-level techniques, then the use of many stages with separate compressors may become a viable option for achieving temperatures of 77 K with high efficiency. We analyze the ideal thermodynamic efficiency of a cascade Joule-Thomson system for various temperatures down to 77 K and with low pressure ratios. About nine stages are required for 77 K, but fewer stages are also analyzed for operation at higher temperatures. For 77 K, an ideal second-law efficiency of 83 % of Carnot is possible with perfect recuperative heat exchangers and 65 % of Carnot is possible with no recuperative heat exchangers. The results are compared with calculated efficiencies in mixed-refrigerant cryocoolers over the range of 77 K to 200 K. Refrigeration at intermediate temperatures is also available. The use of single-component fluids in each of the stages is expected to eliminate the problem of pulsating flow and temperature oscillations experienced in microcryocoolers using mixed refrigerants.

  16. Calibration and evaluation of a real-time cascade impactor

    SciTech Connect (OSTI)

    Fairchild, C.I.; Wheat, L.D.

    1984-04-01

    A 10-stage cascade impactor made by California Measurement Inc., can determine aerodynamic size distributions of dilute aerosols in a few minutes. Collection of impacted particles on greased, vibrating piezoelectric crystals produces changes in vibrational frequency proportional to the collected mass. Based on frequency changes and sampling time, a data reduction module calculates the mass collected on each stage. Calibration of the assembled impactor was performed with monodisperse polystyrene latex (PSL) and Eosin-Y (E-Y) aerosols for the lower stages (4-10), and PSL and pollen particles (ragweed and mulberry) for the upper stages (1-3). The stage experimental effective cutoff aerodynamic diameters (ECAD) were up to 22 percent different from theoretical ECADs with the exception of Stages 1 and 2 which were respectively 30 and 35 percent different from theoretical ECADs. The overall loss of particles > 3- and < 0.3-..mu..m was severe. Also, considerable scatter of particles was observed on the collection crystals of Stages 1 and 2. Although a majority of particles were in the impaction area, a large fraction was scattered over the outer portions of these crystals.

  17. THE TURBULENT CASCADE AND PROTON HEATING IN THE SOLAR WIND DURING SOLAR MINIMUM

    SciTech Connect (OSTI)

    Coburn, Jesse T.; Smith, Charles W.; Vasquez, Bernard J.; Stawarz, Joshua E.; Forman, Miriam A. E-mail: Charles.Smith@unh.edu E-mail: Joshua.Stawarz@Colorado.edu

    2012-08-01

    The recently protracted solar minimum provided years of interplanetary data that were largely absent in any association with observed large-scale transient behavior on the Sun. With large-scale shear at 1 AU generally isolated to corotating interaction regions, it is reasonable to ask whether the solar wind is significantly turbulent at this time. We perform a series of third-moment analyses using data from the Advanced Composition Explorer. We show that the solar wind at 1 AU is just as turbulent as at any other time in the solar cycle. Specifically, the turbulent cascade of energy scales in the same manner proportional to the product of wind speed and temperature. Energy cascade rates during solar minimum average a factor of 2-4 higher than during solar maximum, but we contend that this is likely the result of having a different admixture of high-latitude sources.

  18. Existing Whole-House Solutions Case Study: Cascade Apartments - Deep Energy Multifamily Retrofit

    SciTech Connect (OSTI)

    2014-02-01

    In December of 2009-10, King County Housing Authority (KCHA) implemented energy retrofit improvements in the Cascade multifamily community, located in Kent, Washington, which resulted in annual energy cost savings of 22%, improved comfort and air quality for residents, and increased durability of the units. This research effort involved significant coordination from stakeholders KCHA, WA State Department of Commerce, utility Puget Sound Energy, and Cascade tenants. This report focuses on the following three primary Building America research questions: 1. What are the modeled energy savings using DOE low income weatherization approved TREAT software? 2. How did the modeled energy savings compare with measured energy savings from aggregate utility billing analysis? 3. What is the Savings to Investment Ratio of the retrofit package after considering utility window incentives and KCHA capital improvement funding.

  19. Buoyancy effects on conjugate heat transfer due to a laminar impinging jet: Preliminary results

    SciTech Connect (OSTI)

    Altieri, G.; De Luca, V.; Ruocco, G.

    1999-07-01

    A numerical analysis for fluid flow and conjugate conduction/convection heat transfer from a laminar, planar gas jet impingement (JI) on a finite thickness, discretely heated substrate is performed, which includes the effect of buoyancy. The competition between transfer of heat by conduction in the plate and by convection in the fluid is examined. A combination of assisting or opposing mixed convection is modeled, and the related flow field as well as local heat transfer rate is studied as a function of the mixed convection parameter, the Richardson number, for a given geometry and a thermal-fluid base-case. Preliminary evaluations of the heat transfer rate are presented as local Nusselt number distributions, for nonbuoyant, assisted and opposed impinging jets, along the impinged substrate. The complex, non-monotonic progresses of these results justify the inclusion of the conduction mechanism in the substrate, in order to correctly quantify the driving parameters for the heat transfer control. The presented calculations are in fair accordance with existing literature which is limited to pure fluid jet impingement. The inclusion of the conduction mechanism confirms the absence of the conjugate effect when an opposing cooling jet configuration is realized.

  20. Complex systems analysis of series of blackouts: cascading failure, critical points, and self-organization

    SciTech Connect (OSTI)

    Dobson, Ian [University of Wisconsin, Madison; Carreras, Benjamin A [ORNL; Lynch, Vickie E [ORNL; Newman, David E [University of Alaska

    2007-01-01

    We give an overview of a complex systems approach to large blackouts of electric power transmission systems caused by cascading failure. Instead of looking at the details of particular blackouts, we study the statistics and dynamics of series of blackouts with approximate global models. Blackout data from several countries suggest that the frequency of large blackouts is governed by a power law. The power law makes the risk of large blackouts consequential and is consistent with the power system being a complex system designed and operated near a critical point. Power system overall loading or stress relative to operating limits is a key factor affecting the risk of cascading failure. Power system blackout models and abstract models of cascading failure show critical points with power law behavior as load is increased. To explain why the power system is operated near these critical points and inspired by concepts from self-organized criticality, we suggest that power system operating margins evolve slowly to near a critical point and confirm this idea using a power system model. The slow evolution of the power system is driven by a steady increase in electric loading, economic pressures to maximize the use of the grid, and the engineering responses to blackouts that upgrade the system. Mitigation of blackout risk should account for dynamical effects in complex self-organized critical systems. For example, some methods of suppressing small blackouts could ultimately increase the risk of large blackouts.

  1. Self-similar inverse cascade of magnetic helicity driven by the chiral anomaly

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

    Hirono, Yuji; Kharzeev, Dmitri E.; Yin, Yi

    2015-12-28

    For systems with charged chiral fermions, the imbalance of chirality in the presence of magnetic field generates an electric current—this is the chiral magnetic effect (CME). We study the dynamical real-time evolution of electromagnetic fields coupled by the anomaly to the chiral charge density and the CME current by solving the Maxwell-Chern-Simons equations. We find that the CME induces the inverse cascade of magnetic helicity toward the large distances, and that at late times this cascade becomes self-similar, with universal exponents. We also find that in terms of gauge field topology the inverse cascade represents the transition from linked electricmore » and magnetic fields (Hopfions) to the knotted configuration of magnetic field (Chandrasekhar-Kendall states). The magnetic reconnections are accompanied by the pulses of the CME current directed along the magnetic field lines. In conclusion, we devise an experimental signature of these phenomena in heavy ion collisions, and speculate about implications for condensed matter systems.« less

  2. MAGNETIC ENERGY CASCADE IN SPHERICAL GEOMETRY. I. THE STELLAR CONVECTIVE DYNAMO CASE

    SciTech Connect (OSTI)

    Strugarek, A.; Brun, A. S.; Mathis, S.

    2013-02-20

    We present a method to characterize the spectral transfers of magnetic energy between scales in simulations of stellar convective dynamos. The full triadic transfer functions are computed thanks to analytical coupling relations of spherical harmonics based on the Clebsch-Gordan coefficients. The method is applied to mean field {alpha}{Omega} dynamo models as benchmark tests. From a physical standpoint, the decomposition of the dynamo field into primary and secondary dynamo families proves very instructive in the {alpha}{Omega} case. The same method is then applied to a fully turbulent dynamo in a solar convection zone, modeled with the three-dimensional MHD Anelastic Spherical Harmonics code. The initial growth of the magnetic energy spectrum is shown to be non-local. It mainly reproduces the kinetic energy spectrum of convection at intermediate scales. During the saturation phase, two kinds of direct magnetic energy cascades are observed in regions encompassing the smallest scales involved in the simulation. The first cascade is obtained through the shearing of the magnetic field by the large-scale differential rotation that effectively cascades magnetic energy. The second is a generalized cascade that involves a range of local magnetic and velocity scales. Non-local transfers appear to be significant, such that the net transfers cannot be reduced to the dynamics of a small set of modes. The saturation of the large-scale axisymmetric dipole and quadrupole is detailed. In particular, the dipole is saturated by a non-local interaction involving the most energetic scale of the magnetic energy spectrum, which points to the importance of the magnetic Prandtl number for large-scale dynamos.

  3. Building America Whole-House Solutions for Existing Homes: Cascade Apartments- Deep Energy Multifamily Retrofit (Fact Sheet)

    Broader source: Energy.gov [DOE]

    In December of 2009-10, King County Housing Authority implemented energy retrofit improvements in the Cascade multifamily community, located in Kent, Washington, which resulted in annual energy cost savings of 22%, improved comfort and air quality for residents, and increased durability of the units.

  4. Fundamental Frequency Switching Control of Seven-Level Hybrid Cascaded H-bridge Multilevel Inverter

    SciTech Connect (OSTI)

    Du, Zhong; Chiasson, John N; Ozpineci, Burak; Tolbert, Leon M

    2009-01-01

    This paper presents a cascaded H-bridge multilevel inverter that can be implemented using only a single dc power source and capacitors. Standard cascaded multilevel inverters require n dc sources for 2n + 1 levels. Without requiring transformers, the scheme proposed here allows the use of a single dc power source (e.g., a battery or a fuel cell stack) with the remaining n-1 dc sources being capacitors, which is referred to as hybrid cascaded H-bridge multilevel inverter (HCMLI) in this paper. It is shown that the inverter can simultaneously maintain the dc voltage level of the capacitors and choose a fundamental frequency switching pattern to produce a nearly sinusoidal output. HCMLI using only a single dc source for each phase is promising for high-power motor drive applications as it significantly decreases the number of required dc power supplies, provides high-quality output power due to its high number of output levels, and results in high conversion efficiency and low thermal stress as it uses a fundamental frequency switching scheme. This paper mainly discusses control of seven-level HCMLI with fundamental frequency switching control and how its modulation index range can be extended using triplen harmonic compensation.

  5. Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

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

    Xiao, Bailu; Hang, Lijun; Mei, Jun; Riley, Cameron; Tolbert, Leon M.; Ozpineci, Burak

    2014-09-04

    This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is alsomore » proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.« less

  6. Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

    SciTech Connect (OSTI)

    Xiao, Bailu; Hang, Lijun; Mei, Jun; Riley, Cameron; Tolbert, Leon M.; Ozpineci, Burak

    2014-09-04

    This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is also proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.

  7. Unlimited Damage Accumulation in Metallic Materials Under Cascade-Damage Conditions

    SciTech Connect (OSTI)

    Barashev, Aleksandr; Golubov, Stanislav I

    2008-09-01

    Most experiments on neutron or heavy-ion cascade-produced irradiation of pure metals and metallic alloys demonstrate unlimited void growth as well as development of the dislocation structure. In contrast, the theory of radiation damage predicts saturation of void swelling at sufficiently high irradiation doses and, accordingly, termination of accumulation of interstitial-type defects. It is shown in the present paper that, under conditions of steady production of one-dimensionally (1-D) mobile clusters of self-interstitial atoms (SIAs) in displacement cascades, any one of the following three conditions can result in indefinite damage accumulation. First, if the fraction of SIAs generated in the clustered form is smaller than some finite value of the order of the dislocation bias factor. Second, if solute, impurity or transmuted atoms form atmospheres around voids and repel the SIA clusters. Third, if spatial correlations between voids and other defects, such as second-phase precipitates and dislocations, exist that provide shadowing of voids from the SIA clusters. The driving force for the development of such correlations is the same as for void lattice formation and is argued to be always present under cascade-damage conditions. It is emphasised that the mean-free path of 1-D migrating SIA clusters is typically at least an order of magnitude longer than the average distance between microstructural defects; hence spatial correlations on the same scale should be taken into consideration. A way of developing a predictive theory is discussed. An interpretation

  8. Cable Effects Study. Tangents, Rabbit Holes, Dead Ends, and Valuable Results

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

    Ardelean, Emil V.; Babuška, Vít; Goodding, James C.; Coombs, Douglas M.; Robertson, Lawrence M.; Lane, Steven A.

    2014-08-04

    Lessons learned during a study on the effects that electrical power and signal wiring harness cables introduce on the dynamic response of precision spacecraft is presented, along with the most significant results. Our study was a three year effort to discover a set of practical approaches for updating well-defined dynamic models of harness-free structures where knowledge of the cable type, position, and tie-down method are known. Although cables are found on every satellite, the focus was on precision, low damping, and very flexible structures. Obstacles encountered, classified as tangents, rabbit holes, and dead ends, offer practical lessons for structural dynamicsmore » research. The paper traces the historical, experiential progression of the project, describing how the obstacles affected the project. Methods were developed to estimate cable properties. Problems were encountered because of the flexible, highly damped nature of cables. A beam was used as a test article to validate experimentally derived cable properties and to refine the assumptions regarding boundary conditions. Furthermore, a spacecraft bus-like panel with cables attached was designed, and finite element models were developed and validated through experiment. Various paths were investigated at each stage before a consistent test and analysis methodology was developed« less

  9. Cable Effects Study. Tangents, Rabbit Holes, Dead Ends, and Valuable Results

    SciTech Connect (OSTI)

    Ardelean, Emil V.; Babuška, Vít; Goodding, James C.; Coombs, Douglas M.; Robertson, Lawrence M.; Lane, Steven A.

    2014-08-04

    Lessons learned during a study on the effects that electrical power and signal wiring harness cables introduce on the dynamic response of precision spacecraft is presented, along with the most significant results. Our study was a three year effort to discover a set of practical approaches for updating well-defined dynamic models of harness-free structures where knowledge of the cable type, position, and tie-down method are known. Although cables are found on every satellite, the focus was on precision, low damping, and very flexible structures. Obstacles encountered, classified as tangents, rabbit holes, and dead ends, offer practical lessons for structural dynamics research. The paper traces the historical, experiential progression of the project, describing how the obstacles affected the project. Methods were developed to estimate cable properties. Problems were encountered because of the flexible, highly damped nature of cables. A beam was used as a test article to validate experimentally derived cable properties and to refine the assumptions regarding boundary conditions. Furthermore, a spacecraft bus-like panel with cables attached was designed, and finite element models were developed and validated through experiment. Various paths were investigated at each stage before a consistent test and analysis methodology was developed

  10. Analysis of gas centrifuge cascade for separation of multicomponent isotopes and optimal feed position

    SciTech Connect (OSTI)

    Chuntong Ying; Hongjiang Wu; Mingsheng Zhou; Yuguang Nie; Guangjun Liu

    1997-10-01

    Analysis of the concentration distribution in a gas centrifuge cascade for separation of multicomponent isotope mixtures is different from that in a cascade for separation of two-component mixtures. This paper presents the governing equations for a multicomponent isotope separation cascade. Numerically predicted separation factors for the gas centrifuge cascade agree well with the experimental data. A theoretical optimal feed position is derived for a short square cascade for a two-component mixture in a close-separation case. The optimal feed position for a gas centrifuge cascade for separation of multicomponent mixture is discussed.

  11. Molecular dynamics modeling of atomic displacement cascades in 3C-SiC: Comparison of interatomic potentials

    SciTech Connect (OSTI)

    Samolyuk, German D.; Osetskiy, Yury N.; Stoller, Roger E.

    2015-06-03

    We used molecular dynamics modeling of atomic displacement cascades to characterize the nature of primary radiation damage in 3C-SiC. We demonstrated that the most commonly used interatomic potentials are inconsistent with ab initio calculations of defect energetics. Both the Tersoff potential used in this work and a modified embedded-atom method potential reveal a barrier to recombination of the carbon interstitial and carbon vacancy which is much higher than the density functional theory (DFT) results. The barrier obtained with a newer potential by Gao and Weber is closer to the DFT result. This difference results in significant differences in the cascade production of point defects. We have completed both 10 keV and 50 keV cascade simulations in 3C-SiC at a range of temperatures. In contrast to the Tersoff potential, the Gao-Weber potential produces almost twice as many C vacancies and interstitials at the time of maximum disorder (~0.2 ps) but only about 25% more stable defects at the end of the simulation. Only about 20% of the carbon defects produced with the Tersoff potential recombine during the in-cascade annealing phase, while about 60% recombine with the Gao-Weber potential.

  12. First principle calculations of effective exchange integrals: Comparison between SR (BS) and MR computational results

    SciTech Connect (OSTI)

    Yamaguchi, Kizashi; Nishihara, Satomichi; Saito, Toru; Yamanaka, Shusuke; Kitagawa, Yasutaka; Kawakami, Takashi; Yamada, Satoru; Isobe, Hiroshi; Okumura, Mitsutaka

    2015-01-22

    First principle calculations of effective exchange integrals (J) in the Heisenberg model for diradical species were performed by both symmetry-adapted (SA) multi-reference (MR) and broken-symmetry (BS) single reference (SR) methods. Mukherjee-type (Mk) state specific (SS) MR coupled-cluster (CC) calculations by the use of natural orbital (NO) references of ROHF, UHF, UDFT and CASSCF solutions were carried out to elucidate J values for di- and poly-radical species. Spin-unrestricted Hartree Fock (UHF) based coupled-cluster (CC) computations were also performed to these species. Comparison between UHF-NO(UNO)-MkMRCC and BS UHF-CC computational results indicated that spin-contamination of UHF-CC solutions still remains at the SD level. In order to eliminate the spin contamination, approximate spin-projection (AP) scheme was applied for UCC, and the AP procedure indeed corrected the error to yield good agreement with MkMRCC in energy. The CC double with spin-unrestricted Brueckner's orbital (UBD) was furthermore employed for these species, showing that spin-contamination involved in UHF solutions is largely suppressed, and therefore AP scheme for UBCCD removed easily the rest of spin-contamination. We also performed spin-unrestricted pure- and hybrid-density functional theory (UDFT) calculations of diradical and polyradical species. Three different computational schemes for total spin angular momentums were examined for the AP correction of the hybrid (H) UDFT. HUDFT calculations followed by AP, HUDFT(AP), yielded the S-T gaps that were qualitatively in good agreement with those of MkMRCCSD, UHF-CC(AP) and UB-CC(AP). Thus a systematic comparison among MkMRCCSD, UCC(AP) UBD(AP) and UDFT(AP) was performed concerning with the first principle calculations of J values in di- and poly-radical species. It was found that BS (AP) methods reproduce MkMRCCSD results, indicating their applicability to large exchange coupled systems.

  13. Cascades/Aleutian Play Fairway Analysis: Data and Map Files

    SciTech Connect (OSTI)

    Lisa Shevenell

    2015-11-15

    Contains Excel data files used to quantifiably rank the geothermal potential of each of the young volcanic centers of the Cascade and Aleutian Arcs using world power production volcanic centers as benchmarks. Also contains shapefiles used in play fairway analysis with power plant, volcano, geochemistry and structural data.

  14. Oregon Cascades Play Fairway Analysis: Raster Datasets and Models

    SciTech Connect (OSTI)

    Adam Brandt

    2015-11-15

    This submission includes maps of the spatial distribution of basaltic, and felsic rocks in the Oregon Cascades. It also includes a final Play Fairway Analysis (PFA) model, with the heat and permeability composite risk segments (CRS) supplied separately. Metadata for each raster dataset can be found within the zip files, in the TIF images

  15. Assessment of Critical Events Corridors through Multivariate Cascading Outages Analysis

    SciTech Connect (OSTI)

    Makarov, Yuri V.; Samaan, Nader A.; Diao, Ruisheng; Kumbale, Murali; Chen, Yousu; Singh, Ruchi; Green, Irina; Morgan, Mark P.

    2011-10-17

    Massive blackouts of electrical power systems in North America over the past decade has focused increasing attention upon ways to identify and simulate network events that may potentially lead to widespread network collapse. This paper summarizes a method to simulate power-system vulnerability to cascading failures to a supplied set of initiating events synonymously termed as Extreme Events. The implemented simulation method is currently confined to simulating steady state power-system response to a set of extreme events. The outlined method of simulation is meant to augment and provide a new insight into bulk power transmission network planning that at present remains mainly confined to maintaining power system security for single and double component outages under a number of projected future network operating conditions. Although one of the aims of this paper is to demonstrate the feasibility of simulating network vulnerability to cascading outages, a more important goal has been to determine vulnerable parts of the network that may potentially be strengthened in practice so as to mitigate system susceptibility to cascading failures. This paper proposes to demonstrate a systematic approach to analyze extreme events and identify vulnerable system elements that may be contributing to cascading outages. The hypothesis of critical events corridors is proposed to represent repeating sequential outages that can occur in the system for multiple initiating events. The new concept helps to identify system reinforcements that planners could engineer in order to 'break' the critical events sequences and therefore lessen the likelihood of cascading outages. This hypothesis has been successfully validated with a California power system model.

  16. Nuclear Reactions X-Sections By Evaporation Model, Gamma-Cascades

    Energy Science and Technology Software Center (OSTI)

    2000-06-27

    Calculation of energy-averaged cross sections for nuclear reactions with emission of particles and gamma rays and fission. The models employed are the evaporation model with inclusion of pre-equilibrium decay and gamma ray cascade model. Angular momentum and parity conservation are accounted for. Major improvement to the 1976 STAPRE program (NEA 0461) relates to level density approach, implemwnted in subroutine ZSTDE. Generalized superfluid model is incorporated, Boltzman-gas modelling of intrinsic state density and semi-empirical modelling ofmore » a few quasiparticle effects in total level density in equilibrium and saddle deformations of actinide nuclei.« less

  17. Controlling the secondary flow in a turbine cascade by three-dimensional airfoil design and endwall contouring

    SciTech Connect (OSTI)

    Duden, A.; Fottner, L.; Raab, I.

    1999-04-01

    A highly loaded turbine cascade has been redesigned with the objective to reduce the secondary flow by applying endwall contouring and three-dimensional airfoil design in the endwall regions. The overall loading and the axial area ratio of the cascade have been kept constant. With the tools of a three-dimensional design environment, a systematic study has been carried out regarding several features of the endwall pressure distribution and their influence on the secondary flow. Two optimized configurations have been investigated in a high-speed cascade wind tunnel. The flow field traverses showed improvements concerning the radial extent of the secondary flow and a decrease in secondary loss of 26%. Unfortunately this reduction was counterbalanced by increased profile losses and higher inlet losses due to increased blockage. The striking feature of the cascade with endwall contouring and three-dimensional airfoil design was a significant reduction of the exit flow angle deviations connected with the secondary flow. The predictions obtained by the three-dimensional Navier-Stokes solver TRACE{_}S showed a remarkable agreement with the experimental results.

  18. Electrical flicker-noise generated by filling and emptying of impurity states in injectors of quantum-cascade lasers

    SciTech Connect (OSTI)

    Yamanishi, Masamichi Hirohata, Tooru; Hayashi, Syohei; Fujita, Kazuue; Tanaka, Kazunori

    2014-11-14

    Free running line-widths (>100?kHz), much broader than intrinsic line-widths ?100?Hz, of existing quantum-cascade lasers are governed by strong flicker frequency-noise originating from electrical flicker noise. Understanding of microscopic origins of the electrical flicker noises in quantum-cascade lasers is crucially important for the reduction of strength of flicker frequency-noise without assistances of any type of feedback schemes. In this article, an ad hoc model that is based on fluctuating charge-dipoles induced by electron trappings and de-trappings at indispensable impurity states in injector super-lattices of a quantum-cascade laser is proposed, developing theoretical framework based on the model. The validity of the present model is evaluated by comparing theoretical voltage-noise power spectral densities based on the model with experimental ones obtained by using mid-infrared quantum-cascade lasers with designed impurity-positioning. The obtained experimental results on flicker noises, in comparison with the theoretical ones, shed light on physical mechanisms, such as the inherent one due to impurity states in their injectors and extrinsic ones due to surface states on the ridge-walls and due to residual deep traps, for electrical flicker-noise generation in existing mid-infrared quantum-cascade lasers. It is shown theoretically that quasi-delta doping of impurities in their injectors leads to strong suppression of electrical flicker noise by minimization of the dipole length at a certain temperature, for instance ?300?K and, in turn, is expected to result in substantial narrowing of the free running line-width down below 10?kHz.

  19. Field-Scale Effective Matrix Diffusion Coefficient for FracturedRock: Results From Literature Survey

    SciTech Connect (OSTI)

    Zhou, Quanlin; Liu, Hui Hai; Molz, Fred J.; Zhang, Yingqi; Bodvarsson, Gudmundur S.

    2005-03-28

    Matrix diffusion is an important mechanism for solutetransport in fractured rock. We recently conducted a literature survey onthe effective matrix diffusion coefficient, Dem, a key parameter fordescribing matrix diffusion processes at the field scale. Forty fieldtracer tests at 15 fractured geologic sites were surveyed and selectedfor study, based on data availability and quality. Field-scale Dem valueswere calculated, either directly using data reported in the literature orby reanalyzing the corresponding field tracer tests. Surveyed dataindicate that the effective-matrix-diffusion-coefficient factor FD(defined as the ratio of Dem to the lab-scale matrix diffusioncoefficient [Dem]of the same tracer) is generally larger than one,indicating that the effective matrix diffusion coefficient in the fieldis comparatively larger than the matrix diffusion coefficient at therock-core scale. This larger value could be attributed to the manymass-transfer processes at different scales in naturally heterogeneous,fractured rock systems. Furthermore, we observed a moderate trend towardsystematic increase in the emDFmDDF value with observation scale,indicating that the effective matrix diffusion coefficient is likely tobe statistically scale dependent. The FD value ranges from 1 to 10,000for observation scales from 5 to 2,000 m. At a given scale, the FD valuevaries by two orders of magnitude, reflecting the influence of differingdegrees of fractured rock heterogeneity at different sites. In addition,the surveyed data indicate that field-scale longitudinal dispersivitygenerally increases with observation scale, which is consistent withprevious studies. The scale-dependent field-scale matrix diffusioncoefficient (and dispersivity) may have significant implications forassessing long-term, large-scale radionuclide and contaminant transportevents in fractured rock, both for nuclear waste disposal and contaminantremediation.

  20. Method of altering the effective bulk density of solid material and the resulting product

    DOE Patents [OSTI]

    Kool, Lawrence B.; Nolen, Robert L.; Solomon, David E.

    1983-01-01

    A method of adjustably tailoring the effective bulk density of a solid material in which a mixture comprising the solid material, a film-forming polymer and a volatile solvent are sprayed into a drying chamber such that the solvent evaporates and the polymer dries into hollow shells having the solid material captured within the shell walls. Shell density may be varied as a function of solid/polymer concentration, droplet size and drying temperature.

  1. IEA Webinar: Cascading of woody biomass definitions, policies, and effects

    Energy Savers [EERE]

    IDENTIFY AND PROTECT YOUR VITAL RECORDS IDENTIFY AND PROTECT YOUR VITAL RECORDS To comply with the statutory and regulatory requirements, the Department of Energy (DOE) issued DOE O 243.2, Vital Records, which sets forth requirements and responsibilities for implementing and maintaining a vital records program IDENTIFY AND PROTECT YOUR VITAL RECORDS (112.57 KB) More Documents & Publications Identify and Protect Your Vital Records DOE O 243.1B, Records Management Program DISPOSITION

  2. FIELD-SCALE EFFECTIVE MATRIX DIFFUSION COEFFICIENT FOR FRACTURED ROCK:RESULTS FROM LITERATURE SURVEY

    SciTech Connect (OSTI)

    Q. Zhou; Hui-Hai Liu; F.J. Molz; Y. Zhang; G.S. Bodvarsson

    2005-04-08

    Matrix diffusion is an important mechanism for solute transport in fractured rock. We recently conducted a literature survey on the effective matrix diffusion coefficient, D{sub m}{sup e}, a key parameter for describing matrix diffusion processes at the field scale. Forty field tracer tests at 15 fractured geologic sites were surveyed and selected for the study, based on data availability and quality. Field-scale D{sub m}{sup e} values were calculated, either directly using data reported in the literature or by reanalyzing the corresponding field tracer tests. Surveyed data indicate that the effective-matrix-diffusion-coefficient factor F{sub D} (defined as the ratio of D{sub m}{sup e} to the lab-scale matrix diffusion coefficient [D{sub m}] of the same tracer) is generally larger than one, indicating that the effective matrix diffusion coefficient in the field is comparatively larger than the matrix diffusion coefficient at the rock-core scale. This larger value can be attributed to the many mass-transfer processes at different scales in naturally heterogeneous, fractured rock systems. Furthermore, we observed a moderate trend toward systematic increase in the F{sub D} value with observation scale, indicating that the effective matrix diffusion coefficient is likely to be statistically scale dependent. The F{sub D} value ranges from 1 to 10,000 for observation scales from 5 to 2,000 m. At a given scale, the F{sub D} value varies by two orders of magnitude, reflecting the influence of differing degrees of fractured rock heterogeneity at different sites. In addition, the surveyed data indicate that field-scale longitudinal dispersivity generally increases with observation scale, which is consistent with previous studies. The scale-dependent field-scale matrix diffusion coefficient (and dispersivity) may have significant implications for assessing long-term, large-scale radionuclide and contaminant transport events in fractured rock, both for nuclear waste disposal

  3. Perform Tests and Document Results and Analysis of Oxide Layer Effects and Comparisons

    SciTech Connect (OSTI)

    Collins, E. D.; DelCul, G. D.; Spencer, B. B.; Hunt, R. D.; Ausmus, C.

    2014-08-30

    During the initial feasibility test using actual used nuclear fuel (UNF) cladding in FY 2012, an incubation period of 30–45 minutes was observed in the initial dry chlorination. The cladding hull used in the test had been previously oxidized in a dry air oxidation pretreatment prior to removal of the fuel. The cause of this incubation period was attributed to the resistance to chlorination of an oxide layer imparted by the dry oxidation pretreatment on the cladding. Subsequently in 2013, researchers at the Korea Atomic Energy Institute (KAERI) reported on their chlorination study [R1] on ~9-gram samples of unirradiated ZirloTM cladding tubes that had been previously oxidized in air at 500oC for various time periods to impart oxide layers of varying thickness. In early 2014, discussions with Indefinite Delivery, Indefinite Quantity (IDIQ) contracted technical consultants from Westinghouse described their previous development (and patents) [R2] on methods of chemical washing to remove some or all of the hydrous oxide layer imparted on UNF cladding during irradiation in light water reactors (LWRs) . Thus, the Oak Ridge National Laboratory (ORNL) study, described herein, was planned to extend the KAERI study on the effects of anhydrous oxide layers, but on larger ~100-gram samples of unirradiated zirconium alloy cladding tubes, and to investigate the effects of various methods of chemical pretreatment prior to chlorination with 100% chlorine on the average reaction rates and Cl2 usage efficiencies.

  4. Imaging of free carriers in semiconductors via optical feedback in terahertz quantum cascade lasers

    SciTech Connect (OSTI)

    Mezzapesa, F. P. Brambilla, M.; Dabbicco, M.; Scamarcio, G.; Columbo, L. L.; Vitiello, M. S.

    2014-01-27

    To monitor the density of photo-generated charge carriers on a semiconductor surface, we demonstrate a detectorless imaging system based on the analysis of the optical feedback in terahertz quantum cascade lasers. Photo-excited free electron carriers are created in high resistivity n-type silicon wafers via low power (?40 mW/cm{sup 2}) continuous wave pump laser in the near infrared spectral range. A spatial light modulator allows to directly reconfigure and control the photo-patterned intensity and the associated free-carrier density distribution. The experimental results are in good agreement with the numerical simulations.

  5. Nuclear criticality safety aspects of gaseous uranium hexafluoride (UF{sub 6}) in the diffusion cascade

    SciTech Connect (OSTI)

    Huffer, J.E.

    1997-04-01

    This paper determines the nuclear safety of gaseous UF{sub 6} in the current Gaseous Diffusion Cascade and auxiliary systems. The actual plant safety system settings for pressure trip points are used to determine the maximum amount of HF moderation in the process gas, as well as the corresponding atomic number densities. These inputs are used in KENO V.a criticality safety models which are sized to the actual plant equipment. The ENO V.a calculation results confirm nuclear safety of gaseous UF{sub 6} in plant operations..

  6. Atomic cascade of K{sup -}p and K{sup -}d atoms and Doppler broadening contribution on x-ray widths

    SciTech Connect (OSTI)

    Kalantari, S. Z.; M. Raeisi, G.

    2010-01-15

    In this article we present a new calculation of the cascade of K{sup -}p and K{sup -}d atoms by the Monte Carlo method. Energy dependence of the collisional cascade processes is taken into account. The x-ray yields due to the radiative transition during the cascade are also calculated. We compare our results with the previous calculations by others and by KEK and DEAR experimental data for K{sup -}p atoms. We have also investigated the kinetic energy distribution of K{sup -}p atoms and the role of Coulomb transition on x-ray yields. Finally, the Doppler broadening contribution on the measured width of x-ray spectra are determined. In order to study the strong interaction in low energies, our results for x-ray yields from K{sup -}p and K{sup -}d atoms can be compared with the forthcoming SIDDHARTA collaboration results.

  7. Cascade Apartments - Deep Energy Multifamily Retrofit , Kent, Washington (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2014-02-01

    In December of 2009-10, King County Housing Authority (KCHA) implemented energy retrofit improvements in the Cascade multifamily community, located in Kent, Washington (marine climate.)This research effort involved significant coordination from stakeholders KCHA, WA State Department of Commerce, utility Puget Sound Energy, and Cascade tenants. This report focuses on the following three primary BA research questions : 1. What are the modeled energy savings using DOE low income weatherization approved TREAT software? 2. How did the modeled energy savings compare with measured energy savings from aggregate utility billing analysis? 3. What is the Savings to Investment Ratio (SIR) of the retrofit package after considering utility window incentives and KCHA capitol improvement funding.

  8. Cascade heat recovery with coproduct gas production

    DOE Patents [OSTI]

    Brown, W.R.; Cassano, A.A.; Dunbobbin, B.R.; Rao, P.; Erickson, D.C.

    1986-10-14

    A process for the integration of a chemical absorption separation of oxygen and nitrogen from air with a combustion process is set forth wherein excess temperature availability from the combustion process is more effectively utilized to desorb oxygen product from the absorbent and then the sensible heat and absorption reaction heat is further utilized to produce a high temperature process stream. The oxygen may be utilized to enrich the combustion process wherein the high temperature heat for desorption is conducted in a heat exchange preferably performed with a pressure differential of less than 10 atmospheres which provides considerable flexibility in the heat exchange. 4 figs.

  9. Cascade heat recovery with coproduct gas production

    DOE Patents [OSTI]

    Brown, William R.; Cassano, Anthony A.; Dunbobbin, Brian R.; Rao, Pradip; Erickson, Donald C.

    1986-01-01

    A process for the integration of a chemical absorption separation of oxygen and nitrogen from air with a combustion process is set forth wherein excess temperature availability from the combustion process is more effectively utilized to desorb oxygen product from the absorbent and then the sensible heat and absorption reaction heat is further utilized to produce a high temperature process stream. The oxygen may be utilized to enrich the combustion process wherein the high temperature heat for desorption is conducted in a heat exchange preferably performed with a pressure differential of less than 10 atmospheres which provides considerable flexibility in the heat exchange.

  10. Crystal Structure of Cascade | Stanford Synchrotron Radiation Lightsource

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

    Crystal Structure of Cascade Friday, January 30, 2015 Immune pathways protect all organisms from infection by genetic invaders such as viruses. It was recently discovered that prokaryotes protect against invasion by bacteriophages via an RNA based adaptive immune system, called the CRISPR system (1, 2). By acting as a barrier to the exchange of genetic information, a major route for the acquisition of antibiotic-resistance and virulence factors, the CRISPR system modulates the evolution of

  11. Variable cascade dynamics and intermittency in the solar wind at 1 AU

    SciTech Connect (OSTI)

    Coburn, Jesse T.; Smith, Charles W.; Vasquez, Bernard J.; Forman, Miriam A.; Stawarz, Julia E. E-mail: Charles.Smith@unh.edu E-mail: Miriam.Forman@sunysb.edu

    2014-05-01

    In recent studies by ourselves and others of third-moment expressions for the rate of energy cascade in the solar wind, it has been shown that relatively large volumes of data are needed to produce convergent averages. These averages are in good agreement with independently obtained estimates for the average heating rate for a solar wind plasma under those conditions. The unanswered question has been whether the convergence issue is the result of intermittent dynamics or simple measurement uncertainties. In other words, is the difficulty in obtaining a single result that characterizes many similarly prepared samples due to in situ dynamics that create physically real variations or simple statistics? There have been publications showing evidence of intermittent dynamics in the solar wind. Here we show that the third-moment expressions and the computed energy cascade for relatively small samples of data comparable to the correlation length are generally well-formed estimates of the local dynamics. This leads us to conclude that intermittency and not simple measurement uncertainties are responsible for the slow convergence to expected heating rates. We partially characterize the scale size of the intermittency to be comparable to or smaller than the correlation length of the turbulence and we attempt to rephrase the discussion of third moments in terms of intermittent dynamics.

  12. IAEA Verification Experiment at the Portsmouth Gaseous Diffusion Plant: Report on the Cascade Header Enrichment Monitor

    SciTech Connect (OSTI)

    P. L. Kerr; D. A. Close; W. S. Johnson; R. M. Kandarian; C. E. Moss; C. D. Romero

    1999-03-01

    The authors describe the Cascade Header Enrichment Monitor (CHEM) for the Portsmouth Gaseous Diffusion Plant at Piketon, Ohio, and present the calibration and measurement results. The US government has offered excess fissile material that is no longer needed for defense purposes for International Atomic Energy Agency (IAEA) inspection. Measurement results provided by the CHEM were used by the IAEA in a verification experiment to provide confidence that the US successfully blended excess highly enriched uranium (HEU) down to low enriched uranium (LEU). The CHEM measured the uranium enrichment in two cascade header pipes, a 20.32-cm HEU pipe and a 7.62-cm product LEU pipe. The CHEM determines the amount of {sup 235}U from the 185.7-keV gamma-ray photopeak and the amount of total uranium by x-ray fluorescence (XRF) of the 98.4-keV x-ray from uranium with a {sup 57}Co XRF source. The ratio yields the enrichment. The CHEM consists of a collimator assembly, an electromechanically cooled germanium detector, and a rack-mounted personal computer running commercial and custom software. The CHEM was installed in December 1997 and was used by the IAEA inspectors for announced and unannounced inspections on the HEU and LEU header pipes through October 1998. The equipment was sealed with tamper-indicating enclosures when the inspectors were not present.

  13. Making Effective User of Compilers at NERSC

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

    Effective Use of Compilers at NERSC Michael Stewart NERSC User Services Group August 15, 2012 Introduction ● Description of the Hopper compiling environment. ● Strengths and weaknesses of each compiler. ● Advice on choosing the most appropriate compiler for your work. ● Comparative results on benchmarks and other codes. ● How to use the compilers effectively. ● Carver compiling environment. ● Plans for the new Cray Cascade system (NERSC 7) compiling environment. ● Your feedback.

  14. Cascaded-systems analyses and the detective quantum efficiency of single-Z x-ray detectors including photoelectric, coherent and incoherent interactions

    SciTech Connect (OSTI)

    Yun, Seungman; Tanguay, Jesse; Cunningham, Ian A.; Kim, Ho Kyung

    2013-04-15

    Purpose: Theoretical models of the detective quantum efficiency (DQE) of x-ray detectors are an important step in new detector development by providing an understanding of performance limitations and benchmarks. Previous cascaded-systems analysis (CSA) models accounted for photoelectric interactions only. This paper describes an extension of the CSA approach to incorporate coherent and incoherent interactions, important for low-Z detectors such as silicon and selenium. Methods: A parallel-cascade approach is used to describe the three types of x-ray interactions. The description of incoherent scatter required developing expressions for signal and noise transfer through an 'energy-labeled reabsorption' process where the parameters describing reabsorption are random functions of the scatter photon energy. The description of coherent scatter requires the use of scatter form factors that may not be accurate for some crystalline detector materials. The model includes the effects of scatter reabsorption and escape, charge collection, secondary quantum sinks, noise aliasing, and additive noise. Model results are validated by Monte Carlo calculations for Si and Se detectors assuming free-atom atomic form factors. Results: The new signal and noise transfer expressions were validated by showing agreement with Monte Carlo results. Coherent and incoherent scatter can degrade the DQE of Si and sometimes Se detectors depending on detector thickness and incident-photon energy. Incoherent scatter can produce a substantial low-frequency drop in the modulation transfer function and DQE. Conclusions: A generally useful CSA model of the DQE is described that is believed valid for any single-Z material up to 10 cycles/mm at both mammographic and radiographic energies within the limitations of Fourier-based linear-systems models and the use of coherent-scatter form factors. The model describes a substantial low-frequency drop in the DQE of Si systems due to incoherent scatter above 20

  15. Molecular dynamics modeling of atomic displacement cascades in 3C-SiC: Comparison of interatomic potentials

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

    Samolyuk, German D.; Osetskiy, Yury N.; Stoller, Roger E.

    2015-06-03

    We used molecular dynamics modeling of atomic displacement cascades to characterize the nature of primary radiation damage in 3C-SiC. We demonstrated that the most commonly used interatomic potentials are inconsistent with ab initio calculations of defect energetics. Both the Tersoff potential used in this work and a modified embedded-atom method potential reveal a barrier to recombination of the carbon interstitial and carbon vacancy which is much higher than the density functional theory (DFT) results. The barrier obtained with a newer potential by Gao and Weber is closer to the DFT result. This difference results in significant differences in the cascademore » production of point defects. We have completed both 10 keV and 50 keV cascade simulations in 3C-SiC at a range of temperatures. In contrast to the Tersoff potential, the Gao-Weber potential produces almost twice as many C vacancies and interstitials at the time of maximum disorder (~0.2 ps) but only about 25% more stable defects at the end of the simulation. Only about 20% of the carbon defects produced with the Tersoff potential recombine during the in-cascade annealing phase, while about 60% recombine with the Gao-Weber potential.« less

  16. Comparative analysis of quantum cascade laser modeling based on density matrices and non-equilibrium Green's functions

    SciTech Connect (OSTI)

    Lindskog, M. Wacker, A.; Wolf, J. M.; Liverini, V.; Faist, J.; Trinite, V.; Maisons, G.; Carras, M.; Aidam, R.; Ostendorf, R.

    2014-09-08

    We study the operation of an 8.5 μm quantum cascade laser based on GaInAs/AlInAs lattice matched to InP using three different simulation models based on density matrix (DM) and non-equilibrium Green's function (NEGF) formulations. The latter advanced scheme serves as a validation for the simpler DM schemes and, at the same time, provides additional insight, such as the temperatures of the sub-band carrier distributions. We find that for the particular quantum cascade laser studied here, the behavior is well described by simple quantum mechanical estimates based on Fermi's golden rule. As a consequence, the DM model, which includes second order currents, agrees well with the NEGF results. Both these simulations are in accordance with previously reported data and a second regrown device.

  17. Numerical Investigation of a Cascaded Longitudinal Space-Charge Amplifier at the Fermilab's Advanced Superconducting Test Accelerator

    SciTech Connect (OSTI)

    Halavanau, A.; Piot, P.

    2015-06-01

    In a cascaded longitudinal space-charge amplifier (LSCA), initial density noise in a relativistic e-beam is amplified via the interplay of longitudinal space charge forces and properly located dispersive sections. This type of amplification process was shown to potentially result in large final density modulations [1] compatible with the production of broadband electromagnetic radiation. The technique was recently demonstrated in the optical domain [2]. In this paper we investigate, via numerical simulations, the performances of a cascaded LSCA beamline at the Fermilab’s Advanced Superconducting Test Accelerator (ASTA). We especially explore the properties of the produced broadband radiation. Our studies have been conducted with a grid-less three-dimensional space-charge algorithm.

  18. Three-Phase Modular Cascaded H-Bridge Multilevel Inverter with Individual MPPT for Grid-Connected Photovoltaic Systems

    SciTech Connect (OSTI)

    Xiao, Bailu; Hang, Lijun; Riley, Cameron; Tolbert, Leon M; Ozpineci, Burak

    2013-01-01

    A three-phase modular cascaded H-bridge multilevel inverter for a grid-connected photovoltaic (PV) system is presented in this paper. To maximize the solar energy extraction of each PV string, an individual maximum power point tracking (MPPT) control scheme is applied, which allows the independent control of each dc-link voltage. PV mismatches may introduce unbalanced power supplied to the three-phase system. To solve this issue, a control scheme with modulation compensation is proposed. The three-phase modular cascaded multilevel inverter prototype has been built. Each H-bridge is connected to a 185 W solar panel. Simulation and experimental results are presented to validate the proposed ideas.

  19. Defect structures induced by high-energy displacement cascades in γ uranium

    SciTech Connect (OSTI)

    Miao, Yinbin; Beeler, Benjamin; Deo, Chaitanya; Baskes, Michael I.; Okuniewski, Maria A.; Stubbins, James F.

    2015-01-01

    Displacement cascade simulations were conducted for the c uranium system based on molecular dynamics. A recently developed modified embedded atom method (MEAM) potential was employed to replicate the atomic interactions while an embedded atom method (EAM) potential was adopted to help characterize the defect structures induced by the displacement cascades. The atomic displacement process was studied by providing primary knock-on atoms (PKAs) with kinetic energies from 1 keV to 50 keV. The influence of the PKA incident direction was examined. The defect structures were analyzed after the systems were fully relaxed. The states of the self-interstitial atoms (SIAs) were categorized into various types of dumbbells, the crowdion, and the octahedral interstitial. The voids were determined to have a polyhedral shape with {110} facets. The size distribution of the voids was also obtained. The results of this study not only expand the knowledge of the microstructural evolution in irradiated c uranium, but also provide valuable references for the radiation-induced defects in uranium alloy fuels.

  20. Electron phonon coupling in Ni-based binary alloys with application to displacement cascade modeling

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

    Samolyuk, German D.; Stocks, George Malcolm; Stoller, Roger E.

    2016-04-01

    Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron–phonon (el–ph) coupling. The el–ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states atmore » the Fermi level, which in turn reduces the el–ph coupling. Thus, the el–ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10–20% in the alloys under consideration.« less

  1. THEORETICAL INVESTIGATION OF MICROSTRUCTURE EVOLUTION AND DEFORMATION OF ZIRCONIUM UNDER CASCADE DAMAGE CONDITIONS

    SciTech Connect (OSTI)

    Barashev, Alexander V; Golubov, Stanislav I; Stoller, Roger E

    2012-06-01

    This work is based on our reaction-diffusion model of radiation growth of Zr-based materials proposed recently in [1]. In [1], the equations for the strain rates in unloaded pure crystal under cascade damage conditions of, e.g., neutron or heavy-ion irradiation were derived as functions of dislocation densities, which include contributions from dislocation loops, and spatial distribution of their Burgers vectors. The model takes into account the intra-cascade clustering of self-interstitial atoms and their one-dimensional diffusion; explains the growth stages, including the break-away growth of pre-annealed samples; and accounts for some striking observations, such as of negative strain in prismatic direction, and co-existence of vacancy- and interstitial-type prismatic loops. In this report, the change of dislocation densities due to accumulation of sessile dislocation loops is taken into account explicitly to investigate the dose dependence of radiation growth. The dose dependence of climb rates of dislocations is calculated, which is important for the climb-induced glide model of radiation creep. The results of fitting the model to available experimental data and some numerical calculations of the strain behavior of Zr for different initial dislocation structures are presented and discussed. The computer code RIMD-ZR.V1 (Radiation Induced Microstructure and Deformation of Zr) developed is described and attached to this report.

  2. Cascade annealing simulations of bcc iron using object kinetic Monte Carlo

    SciTech Connect (OSTI)

    Xu, Haixuan; Osetskiy, Yury N; Stoller, Roger E

    2012-01-01

    Simulations of displacement cascade annealing were carried out using object kinetic Monte Carlo based on an extensive MD database including various primary knock-on atom energies and directions. The sensitivity of the results to a broad range of material and model parameters was examined. The diffusion mechanism of interstitial clusters has been identified to have the most significant impact on the fraction of stable interstitials that escape the cascade region. The maximum level of recombination was observed for the limiting case in which all interstitial clusters exhibit 3D random walk diffusion. The OKMC model was parameterized using two alternative sets of defect migration and binding energies, one from ab initio calculations and the second from an empirical potential. The two sets of data predict essentially the same fraction of surviving defects but different times associated with the defect escape processes. This study provides a comprehensive picture of the first phase of long-term defect evolution in bcc iron and generates information that can be used as input data for mean field rate theory (MFRT) to predict the microstructure evolution of materials under irradiation. In addition, the limitations of the current OKMC model are discussed and a potential way to overcome these limitations is outlined.

  3. Features of primary damage by high energy displacement cascades in concentrated Ni-based alloys

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

    Béland, Laurent Karim; Lu, Chenyang; Osetskiy, Yuri N.; Samolyuk, German D.; Caro, Alfredo; Wang, Lumin; Stoller, Roger E.

    2016-02-25

    Alloying of Ni with Fe or Co reduces primary damage production under ion irradiation. Similar results have been obtained from classical molecular dynamics simulations of 1, 10, 20, and 40 keV collision cascades in Ni, NiFe, and NiCo. In all cases, a mix of imperfect stacking fault tetrahedra, faulted loops with a 1/3 {111} Burgers vector, and glissile interstitial loops with a 1/2 {110} Burgers vector were formed, along with small sessile point defect complexes and clusters. Primary damage reduction occurs by three mechanisms. First, Ni-Co, Ni-Fe, Co-Co, and Fe-Fe short-distance repulsive interactions are stiffer than Ni-Ni interactions, which leadmore » to a decrease in damage formation during the transition from the supersonic ballistic regime to the sonic regime. This largely controls final defect production. Second, alloying decreases thermal conductivity, leading to a longer thermal spike lifetime. The associated annealing reduces final damage production. These two mechanisms are especially important at cascades energies less than 40 keV. Third, at the higher energies, the production of large defect clusters by subcascades is inhibited in the alloys. A number of challenges and limitations pertaining to predictive atomistic modeling of alloys under high-energy particle irradiation are discussed.« less

  4. Type-I interband cascade lasers near 3.2 μm

    SciTech Connect (OSTI)

    Jiang, Yuchao; Li, Lu; Yang, Rui Q.; Gupta, James A.; Aers, Geof C.; Dupont, Emmanuel; Baribeau, Jean-Marc; Wu, Xiaohua; Johnson, Matthew B.

    2015-01-26

    Interband cascade (IC) lasers have been demonstrated based on type-I InGaAsSb/AlAsSb quantum well (QW) active regions. These type-I IC lasers are composed of 6-cascade stages and InAs/AlSb superlattice cladding layers. In contrast to the use of quinary AlGaInAsSb barriers for active region in previous type-I QW lasers, the type-I QW active region in each stage is sandwiched by digitally graded multiple InAs/AlSb QW electron injector and GaSb/AlSb QW hole injector. The fabricated type-I IC lasers were able to operate in continuous wave and pulsed modes at temperatures up to 306 and 365 K, respectively. The threshold current densities of broad-area lasers were around 300 A/cm{sup 2} at 300 K with a lasing wavelength near 3.2 μm. The implications and prospects of these initial results are discussed.

  5. Characterization of collision cascade damage in Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} by HRTEM

    SciTech Connect (OSTI)

    Weber, W.J.; Wang, L.M.

    1994-12-01

    Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} thin crystals become amorphous under ion beam irradiation. The ion dose required for complete amorphization of the thin crystal (critical amorphization dose, D{sub c}) increased with the increasing irradiation temperature and decreased with ion mass at elevated temperatures. Samples irradiated with 1-1.5 MeV Ar{sup +}, Kr{sup +} and Xe{sup +} ions to doses much lower than Dc, in the temperature range from 20 to 498 K were used for a detailed HRTEM study to better understand the amorphization process. The residual collision cascade damage after irradiation appeared as manometer scale amorphous domains. The images of these domains are extremely sensitive to the sample thickness. Small domains of cascade size were only found at the very thin edge of the sample. In thicker regions, amorphous domains appear after higher doses as the result of cascade overlap in projection. At higher temperatures, the observed amorphous domains are smaller indicating thermal recovery at the amorphous/crystalline interface. The amorphous domains are also larger in size after irradiation with ions of higher mass at a fixed ion dose. These results are consistent with the Dc-temperature curves determined by in situ TEM with the HVEM-Tandem Facility at Argonne National Laboratory. The width of the amorphous rim along the edge of the specimen grew with increasing ion dose suggesting that amorphization also proceeds from the sample surface. Images of the collision cascade damage were compared to the cascade sizes calculated with the TRIM code. Some digitally acquired HRTEM images of the cascade damage were processed to reveal more detailed information.

  6. Influence of interface roughness in quantum cascade lasers

    SciTech Connect (OSTI)

    Krivas, K. A.; Winge, D. O.; Franckié, M.; Wacker, A.

    2015-09-21

    We use a numerical model based on non-equilibrium Green's functions to investigate the influence of interface roughness (IFR) scattering in terahertz quantum cascade lasers. We confirm that IFR is an important phenomenon that affects both current and gain. The simulations indicate that IFR causes a leakage current that transfers electrons from the upper to the lower laser state. In certain cases, this current can greatly reduce gain. In addition, individual interfaces and their impact on the renormalized single particle energies are studied and shown to give both blue- and red-shifts of the gain spectrum.

  7. Flat 3-brane with Tension in Cascading Gravity

    SciTech Connect (OSTI)

    Rham, Claudia de; Khoury, Justin; Tolley, Andrew

    2009-10-16

    In the cascading gravity brane-world scenario, our 3-brane lies within a succession of lower-codimension branes, each with their own induced gravity term, embedded into each other in a higher-dimensional space-time. In the (6+1)-dimensional version of this scenario, we show that a 3-brane with tension remains flat, at least for sufficiently small tension that the weak-field approximation is valid. The bulk solution is singular nowhere and remains in the perturbative regime everywhere.

  8. EA-1893: Canby Cascaded Geothermal Development System, Canby, California

    Broader source: Energy.gov [DOE]

    This EA will evaluate the environmental impacts of a proposal by Modoc Contracting Company to use DOE grant funds to fulfill its plan to expand its reliance on geothermal resources by producing more hot water and using it to produce power as well as thermal energy. The goal of the project is to complete a cascaded geothermal system that generates green power for the local community, provides thermal energy to support greenhouse and aquaculture operation, provide sustainable thermal energy for residential units, and eliminate the existing geothermal discharge to a local river. NOTE: This EA has been cancelled.

  9. Selection of potential IAEA inspection strategies involving cascade access at the Portsmouth Gas Centrifuge Enrichment Plant (GCEP)

    SciTech Connect (OSTI)

    Not Available

    1981-04-13

    This report has been prepared as a US contribution to Team 4 of the Hexapartite Safeguards Project. It provides to the Team 4 participants one example of an approach, which has been used in the United States, to developing a range of safeguards strategies involving differing degrees of access to cascade areas of centrifuge enrichment plants. Its purpose is to facilitate the work of other Hexapartite participants in completing Task II of Team 4's terms of reference. The scope of this report is limited to identifying safeguards approaches for the Portsmouth Gas Centrifuge Enrichment Plant (GCEP) which involve differing degrees of access to the cascade area. This report provides a method for selecting cascade access inspection strategies at GCEP which appear promising for more detailed evaluation. It is quite important to note, however, that the effectiveness and practicability of these strategies have not been established at the present. In addition, some strategies have been included on the basis of very preliminary calculations and considerations which have not been validated. Thus, some of these strategies may ultimately be rejected because they prove to be impracticable. Considerations of cost and the possible transfer of information and technology related to the production of enriched uranium will also be pertinent in considering the degrees and frequency of access to the cascade areas of centrifuge enrichment plants. This report describes the process for combining technical measures, implementation approaches and objectives to arrive at the total number of theoretically possible combinations. It then describes how these combinations may be reduced in a series of steps to a number that is more manageable for detailed evaluation. The process is shown schematically.

  10. Inverse Cascade of Non-helical Magnetic Turbulence in a Relativistic...

    Office of Scientific and Technical Information (OSTI)

    Title: Inverse Cascade of Non-helical Magnetic Turbulence in a Relativistic Fluid Authors: Zrake, Jonathan ; KIPAC, Menlo Park Publication Date: 2014-10-23 OSTI Identifier: ...

  11. Pseudorandom functions revisited: The cascade construction and its concrete security

    SciTech Connect (OSTI)

    Bellare, M.; Canetti, R.; Krawczyk, H.

    1996-12-31

    Pseudorandom function families are a powerful cryptographic primitive, yielding, in particular, simple solutions for the main problems in private key cryptography. Their existence based on general assumptions (namely, the existence of one-way functions) has been established. In this work we investigate new ways of designing pseudorandom function families. The goal is to find constructions that are both efficient and secure, and thus eventually to bring the benefits of pseudorandom functions to practice. The basic building blocks in our design are certain limited versions of pseudorandom function families, called finite-length input pseudorandom function families, for which very efficient realizations exist in practical cryptography. Thus rather than starting from one-way functions, we propose constructions of {open_quote}full-fledged{close_quotes} pseudorandom function families from these limited ones. In particular we propose the cascade construction, and provide a concrete security analysis which relates the strength of the cascade to that of the underlying finite pseudorandom function family in a precise and quantitative way.

  12. Geology and geothermal resources of the Santiam Pass area of the Oregon Cascade Range, Deschutes, Jefferson and Linn Counties, Oregon

    SciTech Connect (OSTI)

    Hill, B.E. (ed.)

    1992-10-01

    This open-file report presents the results of the Santiam Pass drilling program. The first phase of this program was to compile all available geological, geophysical and geothermal data for the Santiam Pass area and select a drill site on the basis of these data (see Priest and others, 1987a), A summary of the drilling operations and costs associated with the project are presented in chapter 1 by Hill and Benoit. An Overview of the geology of the Santiam Pass area is presented by Hill and Priest in chapter 2. Geologic mapping and isotopic age determinations in the Santiam Pass-Mount Jefferson area completed since 1987 are summarized in chapter 2. One of the more important conclusions reached in chapter 2 is that a minimum of 2 km vertical displacement has occurred in the High Cascade graben in the Santiam Pass area. The petrology of the Santiam Pass drill core is presented by Hill in chapter 3. Most of the major volcanic units in the core have been analyzed for major, minor, and trace element abundances and have been studied petrographically. Three K-Ar ages are interpreted in conjunction with the magnetostratigraphy of the core to show that the oldest rocks in the core are approximately 1.8 Ma. Geothermal and geophysical data collected from the Santiam Pass well are presented by Blackwell in chapter 4. The Santiam Pass well failed to penetrate beneath the zone of lateral groundwater flow associated with highly permeable Quaternary volcanic rocks. Calculated geothermal gradients range from about 50[degree]C/km at depth 700-900 m, to roughly 110[degree]C/km from 900 m to the bottom of the well at 929 m. Heat-flow values for the bottom part of the hole bracket the regional average for the High Cascades. Blackwell concludes that heat flow along the High Cascades axis is equal to or higher than along the western edge of the High Cascades.

  13. The turbulent cascade and proton heating in the solar wind during solar minimum

    SciTech Connect (OSTI)

    Coburn, Jesse T.; Smith, Charles W.; Vasquez, Bernard J.; Stawarz, Joshua E.; Forman, Miriam A.

    2013-06-13

    Solar wind measurements at 1 AU during the recent solar minimum and previous studies of solar maximum provide an opportunity to study the effects of the changing solar cycle on in situ heating. Our interest is to compare the levels of activity associated with turbulence and proton heating. Large-scale shears in the flow caused by transient activity are a source that drives turbulence that heats the solar wind, but as the solar cycle progresses the dynamics that drive the turbulence and heat the medium are likely to change. The application of third-moment theory to Advanced Composition Explorer (ACE) data gives the turbulent energy cascade rate which is not seen to vary with the solar cycle. Likewise, an empirical heating rate shows no significan changes in proton heating over the cycle.

  14. Major results from safety-related integral effect tests with VISTA-ITL for the SMART design

    SciTech Connect (OSTI)

    Park, H. S.; Min, B. Y.; Shin, Y. C.; Yi, S. J.

    2012-07-01

    A series of integral effect tests (IETs) was performed by the Korea Atomic Energy Research Inst. (KAERI) using the VISTA integral test loop (VISTA-ITL) as a small-scale IET program. Among them this paper presents major results acquired from the safety-related IETs with the VISTA-ITL facility for the SMART design. Three small-break loss-of-coolant accident (SBLOCA) tests of safety injection system (SIS) line break, shutdown cooling system (SCS) line break and pressurizer safety valve (PSV) line break were successfully performed and the transient characteristics of a complete loss of flowrate (CLOF) was simulated properly with the VISTA-ITL facility. (authors)

  15. Influence of wetting effect at the outer surface of the pipe on increase in leak rate - experimental results and discussion

    SciTech Connect (OSTI)

    Isozaki, Toshikuni; Shibata, Katsuyuki

    1997-04-01

    Experimental and computed results applicable to Leak Before Break analysis are presented. The specific area of investigation is the effect of the temperature distribution changes due to wetting of the test pipe near the crack on the increase in the crack opening area and leak rate. Two 12-inch straight pipes subjected to both internal pressure and thermal load, but not to bending load, are modelled. The leak rate was found to be very susceptible to the metal temperature of the piping. In leak rate tests, therefore, it is recommended that temperature distribution be measured precisely for a wide area.

  16. Coherent detection of metal-metal terahertz quantum cascade lasers with improved emission characteristics

    SciTech Connect (OSTI)

    Brewer, Anthony; Beere, Harvey E.; Ritchie, David A. [Semiconductor Physics, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Freeman, Joshua R., E-mail: j.r.freeman@leeds.ac.uk; Cavali, Pierrick; Maysonnave, Jean; Tignon, Jrme; Dhillon, Sukhdeep S. [Laboratoire Pierre Aigrain, Ecole Normale Suprieure, CNRS (UMR 8551), Universit P. et M. Curie, Universit D. Diderot, 75231 Paris Cedex 05 (France)

    2014-02-24

    Coherent detection of emission from quantum cascade lasers with metal-metal waveguides is demonstrated through free-space coupling of a THz pulse to the sub-wavelength waveguide. We implement a simple, monolithic planar horn antenna design on the metal-metal waveguide that reduces the impedance mis-match to the waveguide. The resulting devices show up to 10 times more directed output power than conventional metal-metal waveguides. This enhanced coupling to free-space allows a more efficient injection of broad-band THz pulses into the waveguide. Through this, we are able to seed the laser emission and coherently detect the laser emission by electro-optic sampling.

  17. Multilevel cascade voltage source inverter with separate DC sources

    DOE Patents [OSTI]

    Peng, F.Z.; Lai, J.S.

    1997-06-24

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

  18. Multilevel cascade voltage source inverter with seperate DC sources

    DOE Patents [OSTI]

    Peng, Fang Zheng; Lai, Jih-Sheng

    2001-04-03

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  19. Multilevel cascade voltage source inverter with seperate DC sources

    DOE Patents [OSTI]

    Peng, Fang Zheng; Lai, Jih-Sheng

    1997-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  20. Cascaded'' pilot regulators help reduce LPG loss in hot weather

    SciTech Connect (OSTI)

    Not Available

    1994-08-08

    Fina Oil and Chemical Co. and Fisher Controls International used engineering resourcefulness to overcome heat-induced product loss from LPG storage bullets at Fina's Port Arthur, Tex., refinery. Fina had installed Fisher's Easy Joe 399A-6365, a pilot-operated, back-pressure-type regulator, on its LPG storage facility in 1991 as part of a fuel products modernization project. The regulators helped control the accumulation of noncondensible vapors, which collect in the storage bullets above the LPG. But summer heat extremes and surges in the tanks and lines made it possible for the operating pressure to increase so that the safety relief valve was activated before the pilot regulator was able to stabilize the pressure. The installation of pilot-type regulators, in cascaded, or series, formation, reduced product venting through relief valves.

  1. On the modified active region design of interband cascade lasers

    SciTech Connect (OSTI)

    Motyka, M.; Ryczko, K.; Dyksik, M.; S?k, G.; Misiewicz, J.; Weih, R.; Dallner, M.; Kamp, M.; Hfling, S.

    2015-02-28

    Type II InAs/GaInSb quantum wells (QWs) grown on GaSb or InAs substrates and designed to be integrated in the active region of interband cascade lasers (ICLs) emitting in the mid infrared have been investigated. Optical spectroscopy, combined with band structure calculations, has been used to probe their electronic properties. A design with multiple InAs QWs has been compared with the more common double W-shaped QW and it has been demonstrated that it allows red shifting the emission wavelength and enhancing the transition oscillator strength. This can be beneficial for the improvements of the ICLs performances, especially when considering their long-wavelength operation.

  2. Interband cascade (IC) photovoltaic (PV) architecture for PV devices

    SciTech Connect (OSTI)

    Yang, Rui Q.; Tian, Zhaobing; Mishima, Tetsuya D.; Santos, Michael B.; Johnson, Matthew B.; Klem, John F.

    2015-10-20

    A photovoltaic (PV) device, comprising a PV interband cascade (IC) stage, wherein the IC PV stage comprises an absorption region with a band gap, the absorption region configured to absorb photons, an intraband transport region configured to act as a hole barrier, and an interband tunneling region configured to act as an electron barrier. An IC PV architecture for a photovoltaic device, the IC PV architecture comprising an absorption region, an intraband transport region coupled to the absorption region, and an interband tunneling region coupled to the intraband transport region and to the adjacent absorption region, wherein the absorption region, the intraband transport region, and the interband tunneling region are positioned such that electrons will flow from the absorption region to the intraband transport region to the interband tunneling region.

  3. Multilevel cascade voltage source inverter with seperate DC sources

    DOE Patents [OSTI]

    Peng, Fang Zheng (Knoxville, TN); Lai, Jih-Sheng (Blacksburg, VA)

    2002-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  4. Zeolite membrane cascade for tritium extraction and recovery systems

    SciTech Connect (OSTI)

    Borisevich, O.; Demange, D.; Lefebvre, X.; Kind, M.

    2015-03-15

    Membrane separation by zeolite membranes has been proposed as a pre-concentration stage for the tritium extraction from the purge helium of the breeding blanket combined with a final recovery by the catalytic membrane reactor PERMCAT. This fully continuous operation improves the tritium management in fusion machines, minimizing the tritium inventory. For the first time, the permeation measurements for H{sub 2} - He mixtures through a MFI-alumina hollow fibre membrane has been measured for different compositions (0.1 - 20% H{sub 2}) and temperatures. Such a highly permeable membrane, although it shows a limited selectivity, appears attractive for tritium recovery in the blanket. This will imply its operation in a membrane cascade, for which simulation work is ongoing. Mathematically the process is modeled using mass balance equations that can be transformed into the matrix form and solved iteratively assuming a permeate concentration on the first step of iteration, until the separation requirements are fulfilled.

  5. Contributed Review: Quantum cascade laser based photoacoustic detection of explosives

    SciTech Connect (OSTI)

    Li, J. S. Yu, B.; Fischer, H.; Chen, W.; Yalin, A. P.

    2015-03-15

    Detecting trace explosives and explosive-related compounds has recently become a topic of utmost importance for increasing public security around the world. A wide variety of detection methods and an even wider range of physical chemistry issues are involved in this very challenging area. Optical sensing methods, in particular mid-infrared spectrometry techniques, have a great potential to become a more desirable tools for the detection of explosives. The small size, simplicity, high output power, long-term reliability make external cavity quantum cascade lasers (EC-QCLs) the promising spectroscopic sources for developing analytical instrumentation. This work reviews the current technical progress in EC-QCL-based photoacoustic spectroscopy for explosives detection. The potential for both close-contact and standoff configurations using this technique is completely presented over the course of approximately the last one decade.

  6. Cascaded injection resonator for coherent beam combining of laser arrays

    DOE Patents [OSTI]

    Kireev, Vassili [Sunnyvale, CA; Liu, Yun; Protopopescu, Vladimir [Knoxville, TN; Braiman, Yehuda [Oak Ridge, TN

    2008-10-21

    The invention provides a cascaded injection resonator for coherent beam combining of laser arrays. The resonator comprises a plurality of laser emitters arranged along at least one plane and a beam sampler for reflecting at least a portion of each laser beam that impinges on the beam sampler, the portion of each laser beam from one of the laser emitters being reflected back to another one of the laser emitters to cause a beam to be generated from the other one of the laser emitters to the beam reflector. The beam sampler also transmits a portion of each laser beam to produce a laser output beam such that a plurality of laser output beams of the same frequency are produced. An injection laser beam is directed to a first laser emitter to begin a process of generating and reflecting a laser beam from one laser emitter to another laser emitter in the plurality. A method of practicing the invention is also disclosed.

  7. Integration of quantum cascade lasers and passive waveguides

    SciTech Connect (OSTI)

    Montoya, Juan Wang, Christine; Goyal, Anish; Creedon, Kevin; Connors, Michael; Daulton, Jeffrey; Donnelly, Joseph; Missaggia, Leo; Aleshire, Chris; Sanchez-Rubio, Antonio; Herzog, William

    2015-07-20

    We report on monolithic integration of active quantum cascade laser (QCL) materials with passive waveguides formed by using proton implantation. Proton implantation reduces the electron concentration in the QCL layers by creating deep levels that trap carriers. This strongly reduces the intersubband absorption and the free-carrier absorption in the gain region and surrounding layers, thus significantly reducing optical loss. We have measured loss as low as α = 0.33 cm{sup −1} in λ = 9.6 μm wavelength proton-implanted QCL material. We have also demonstrated lasing in active-passive integrated waveguides. This simple integration technique is anticipated to enable low-cost fabrication in infrared photonic integrated circuits in the mid-infrared (λ ∼ 3–16 μm)

  8. INVERSE CASCADE OF NONHELICAL MAGNETIC TURBULENCE IN A RELATIVISTIC FLUID

    SciTech Connect (OSTI)

    Zrake, Jonathan [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Menlo Park, CA 94025 (United States)

    2014-10-20

    The free decay of nonhelical relativistic magnetohydrodynamic turbulence is studied numerically, and found to exhibit cascading of magnetic energy toward large scales. Evolution of the magnetic energy spectrum P{sub M} (k, t) is self-similar in time and well modeled by a broken power law with subinertial and inertial range indices very close to 7/2 and 2, respectively. The magnetic coherence scale is found to grow in time as t {sup 2/5}, much too slow to account for optical polarization of gamma-ray burst afterglow emission if magnetic energy is to be supplied only at microphysical length scales. No bursty or explosive energy loss is observed in relativistic MHD turbulence having modest magnetization, which constrains magnetic reconnection models for rapid time variability of GRB prompt emission, blazars, and the Crab nebula.

  9. Heat transfer of R-134a in single-tube spray evaporation including lubricant effects and enhanced surface results

    SciTech Connect (OSTI)

    Moeykens, S.A.; Huebsch, W.W.; Pate, M.B.

    1995-08-01

    Single-tube spray evaporation experimental tests were conducted in order to evaluate the average wall heat transfer coefficients for seven different commercially available tubes. Liquid film supply rates were held constant in order to evaluate the effects of the enhancement on shell-side heat transfer under similar conditions. Because the spray evaporation phenomenon is so different from pool boiling, both condensation-type and evaporation-type enhanced surfaces were evaluated. A comparison of the results for all of the tubes showed that the enhanced condensation surfaces performed better than the enhanced boiling surfaces. In addition, the 26-fpi surface tested marginally better than the 40-fpi surface. Small concentrations of a polyol-ester lubricant cause a foaming effect that increases the heat transfer performance. This tendency was seen with both 32-cs and 68-cs polyol-ester oils. The 68-cs lubricant was tested at concentrations of 0.0, 0.5, 1.0, 3.0, and 5.0 with the W-40 fpi and Tu-Cii surfaces. Results with this lubricant show the performance continues to increase through the 3% concentration for most of the heat flux range tested At the upper end of the range tested, the 1.0% mass fraction yielded the best performance. The 32-cs lubricant generated trends similar to those of the 68-cs lubricant. Lubricant concentrations of 1.0%, 2.0%, and 3.0% were evaluated with plain, W-40 fpi, and Tu-Cii surfaces. The 2.0% concentration, not the 1.0 %, generated the best performance at the highest heat flux tested. This difference must be attributed to the difference in the lubricant viscosity.

  10. High field Q slope and the baking effect: Review of recent experimental results and new data on Nb heat treatments

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

    G. Ciovati; Myneni, G.; Stevie, F.; Maheshwari, P.; Griffis, D.

    2010-02-22

    Here, the performance of superconducting radio-frequency (SRF) cavities made of bulk Nb at high fields (peak surface magnetic field greater than about 90 mT) is characterized by exponentially increasing rf losses (high-field Q-slope), in the absence of field emission, which are often mitigated by low temperature (100-140 °C, 12-48 h) baking. In this contribution, recent experimental results and phenomenological models to explain this effect will be briefly reviewed. New experimental results on the high-field Q-slope will be presented for cavities that had been heat treated in a vacuum furnace at high temperature without subsequent chemical etching. These studies are aimedmore » at understanding the role of hydrogen on the high-field Q-slope and at the passivation of the Nb surface during heat treatment. Improvement of the cavity performances, particularly of the cavities’ quality factor, have been obtained following the high temperature heat-treatments, while SIMS surface analysis measurements on Nb samples treated with the cavities revealed significantly lower hydrogen concentration than for samples that followed standard cavity treatments.« less

  11. High field Q slope and the baking effect: Review of recent experimental results and new data on Nb heat treatments

    SciTech Connect (OSTI)

    G. Ciovati, G. Myneni, F. Stevie, P. Maheshwari, D. Griffis

    2010-02-01

    The performance of superconducting radio-frequency (SRF) cavities made of bulk Nb at high fields (peak surface magnetic field greater than about 90 mT) is characterized by exponentially increasing rf losses (high-field Q slope), in the absence of field emission, which are often mitigated by low-temperature (100140C, 1248 h) baking. In this contribution, recent experimental results and phenomenological models to explain this effect will be briefly reviewed. New experimental results on the high-field Q slope will be presented for cavities that had been heat treated in a vacuum furnace at high temperature without subsequent chemical etching. These studies are aimed at understanding the role of hydrogen on the high-field Q slope and at the passivation of the Nb surface during heat treatment. Improvement of the cavity performances, particularly of the cavities quality factor, have been obtained following the high-temperature heat treatments, while secondary ion mass spectroscopy surface analysis measurements on Nb samples treated with the cavities revealed significantly lower hydrogen concentration than for samples that followed standard cavity treatments.

  12. Real-Time Trace Gas Sensing of Fluorocarbons using a Swept-wavelength External Cavity Quantum Cascade Laser

    SciTech Connect (OSTI)

    Phillips, Mark C.; Taubman, Matthew S.; Bernacki, Bruce E.; Cannon, Bret D.; Stahl, Robert D.; Schiffern, John T.; Myers, Tanya L.

    2014-05-04

    We present results demonstrating real-time sensing of four different fluorocarbons at low-ppb concentrations using an external cavity quantum cascade laser (ECQCL) operating in a swept-wavelength configuration. The ECQCL was repeatedly swept over its full tuning range at a 20 Hz rate with a scan rate of 3535 cm-1/s, and a detailed characterization of the ECQCL scan stability and repeatability is presented. The sensor was deployed on a mobile automotive platform to provide spatially resolved detection of fluorocarbons in outdoor experiments. Noise-equivalent detection limits of 800-1000 parts-per-trillion (ppt) are demonstrated for 1 s integration times.

  13. Pump and probe spectroscopy with continuous wave quantum cascade lasers

    SciTech Connect (OSTI)

    Kirkbride, James M. R.; Causier, Sarah K.; Dalton, Andrew R.; Ritchie, Grant A. D.; Weidmann, Damien

    2014-02-07

    This paper details infra-red pump and probe studies on nitric oxide conducted with two continuous wave quantum cascade lasers both operating around 5 μm. The pump laser prepares a velocity selected population in a chosen rotational quantum state of the v = 1 level which is subsequently probed using a second laser tuned to a rotational transition within the v = 2 ← v = 1 hot band. The rapid frequency scan of the probe (with respect to the molecular collision rate) in combination with the velocity selective pumping allows observation of marked rapid passage signatures in the transient absorption profiles from the polarized vibrationally excited sample. These coherent transient signals are influenced by the underlying hyperfine structure of the pump and probe transitions, the sample pressure, and the coherent properties of the lasers. Pulsed pump and probe studies show that the transient absorption signals decay within 1 μs at 50 mTorr total pressure, reflecting both the polarization and population dephasing times of the vibrationally excited sample. The experimental observations are supported by simulation based upon solving the optical Bloch equations for a two level system.

  14. K-311-1/K-310-3 Purge Cascade Process Description, Oak Ridge Environmental Management Accelerated Cleanup Project, Oak Ridge, Tennessee

    SciTech Connect (OSTI)

    Shoemaker J.E.

    2009-05-13

    K-311-1 was constructed along with the rest of the K-25 Building in the 1943-1945 timeframe. K-311-1 was equipped with Size 3 converters and Size 38 Allis Chalmers{trademark} single-stage centrifugal compressors driven by 3600 rpm electric motors, and the unit operated as the 'bottom' unit flow-wise in K-25. The depleted flow from the bottom stage in K-311-1 passed through booster compressors and flowed to the K-601 Building where the depleted or 'tails' material was removed. In 1948, after the K-27 Building was completed, the decision was made to operate K-27 and K-25 in series rather than operate the two buildings as separate entities. To facilitate this operation, concrete bases were poured and two sets of booster compressors were installed in the extreme West end of the K-311-1 cell floor. These compressors were enclosed in heated housings and consisted of Size 38 compressors. One pair was to boost the 'B' flow between K-25 and K-27, and one pair was to boost the 'A' flow between the buildings. Each station operated with one compressor on-stream and the other in standby. (Reference 9) Each station also was equipped with a Size 2 after-cooler located in the discharge stream downstream of the junction of the onstream and standby compressors. Additional gaseous diffusion capacity was added at Oak Ridge as K-29, K-31, and K-33 were constructed and placed in service in the early 1950s. As a result of the additional process equipment added by these buildings, in-leakage of light gases to the cascade including light gases introduced into the cascade as a result of purging operations threatened to exceed the capacity of the existing K-312 Purge Cascade facilities in the K-25 Building. As a result, in 1954 K-311-1 was converted to a side purge cascade to remove light gases from the process gas stream as the stream entered K-25 from K-27. Low molecular weight gas in-leakage in K-33, K-31, K-29, and K-27 was removed by the K-311-1 Side Purge Facility and a relatively pure

  15. Heat Flow From Four New Research Drill Holes In The Western Cascades...

    Open Energy Info (EERE)

    From Four New Research Drill Holes In The Western Cascades, Oregon, Usa Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Heat Flow From Four New...

  16. Hyperspectral microscopy using an external cavity quantum cascade laser and its applications for explosives detection

    SciTech Connect (OSTI)

    Phillips, Mark C.; Suter, Jonathan D.; Bernacki, Bruce E.

    2012-04-01

    A hyperspectral infrared microscope using external cavity quantum cascade laser illumination and a microbolometer focal plane array is used to characterize nanogram-scale particles of the explosives RDX, tetryl, and PETN at fast acquisition rates.

  17. Rapid Swept-Wavelength External Cavity Quantum Cascade Laser for Open Path Sensing

    SciTech Connect (OSTI)

    Brumfield, Brian E.; Phillips, Mark C.

    2015-07-01

    A rapidly tunable external cavity quantum cascade laser system is used for open path sensing. The system permits acquisition of transient absorption spectra over a 125 cm-1 tuning range in less than 0.01 s.

  18. Analysis of Trace Gas Mixtures Using an External Cavity Quantum Cascade Laser Sensor

    SciTech Connect (OSTI)

    Phillips, Mark C.; Taubman, Matthew S.; Brumfield, Brian E.; Kriesel, Jason M.

    2015-07-01

    We measure and analyze mixtures of trace gases at ppb-ppm levels using an external cavity quantum cascade laser sensor with a 1-second response time. Accurate spectral fits are obtained in the presence of overlapping spectra.

  19. Method of independently operating a group of stages within a diffusion cascade

    DOE Patents [OSTI]

    Benedict, Manson; Fruit, Allen J.; Levey, Horace B.

    1976-06-08

    1. A method of operating a group of the diffusion stages of a productive diffusion cascade with countercurrent flow, said group comprising a top and a bottom stage, which comprises isolating said group from said cascade, circulating the diffused gas produced in said top stage to the feed of said bottom stage while at the same time circulating the undiffused gas from said bottom stage to the feed of said top stage whereby major changes in

  20. Role of slope stability in cumulative impact assessment of hydropower development: North Cascades, Washington

    SciTech Connect (OSTI)

    Lee, R.R.; Staub, W.P.

    1993-08-01

    Two environmental assessments considered the potential cumulative environmental impacts resulting from the development of eight proposed hydropower projects in the Nooksack River Basin and 11 proposed projects in the Skagit River Basin, North Cascades, Washington, respectively. While not identified as a target resource, slope stability and the alteration of sediment supply to creeks and river mainstems significantly affect other resources. The slope stability assessment emphasized the potential for cumulative impacts under disturbed conditions (e.g., road construction and timber harvesting) and a landslide-induced pipeline rupture scenario. In the case of small-scale slides, the sluicing action of ruptured pipeline water on the fresh landslide scarp was found to be capable of eroding significantly more material than the original landslide. For large-scale landslides, sluiced material was found to be a small increment of the original landslide. These results predicted that hypothetical accidental pipeline rupture by small-scale landslides may result in potential cumulative impacts for 12 of the 19 projects with pending license applications in both river basins. 5 refs., 2 tabs.

  1. Astrophysical Gyrokinetics: Kinetic and Fluid Turbulent Cascades In Magentized Weakly Collisional Plasmas

    SciTech Connect (OSTI)

    Schekochihin, A. A.; Cowley, S. C.; Dorland, W.; Hammett, G. W.; Howes, G. G.; Quataert, E.; Tatsuno, T.

    2009-04-23

    This paper presents a theoretical framework for understanding plasma turbulence in astrophysical plasmas. It is motivated by observations of electromagnetic and density fluctuations in the solar wind, interstellar medium and galaxy clusters, as well as by models of particle heating in accretion disks. All of these plasmas and many others have turbulentmotions at weakly collisional and collisionless scales. The paper focuses on turbulence in a strong mean magnetic field. The key assumptions are that the turbulent fluctuations are small compared to the mean field, spatially anisotropic with respect to it and that their frequency is low compared to the ion cyclotron frequency. The turbulence is assumed to be forced at some system-specific outer scale. The energy injected at this scale has to be dissipated into heat, which ultimately cannot be accomplished without collisions. A kinetic cascade develops that brings the energy to collisional scales both in space and velocity. The nature of the kinetic cascade in various scale ranges depends on the physics of plasma fluctuations that exist there. There are four special scales that separate physically distinct regimes: the electron and ion gyroscales, the mean free path and the electron diffusion scale. In each of the scale ranges separated by these scales, the fully kinetic problem is systematically reduced to a more physically transparent and computationally tractable system of equations, which are derived in a rigorous way. In the "inertial range" above the ion gyroscale, the kinetic cascade separates into two parts: a cascade of Alfvenic fluctuations and a passive cascade of density and magnetic-fieldstrength fluctuations. The former are governed by the Reduced Magnetohydrodynamic (RMHD) equations at both the collisional and collisionless scales; the latter obey a linear kinetic equation along the (moving) field lines associated with the Alfvenic component (in the collisional limit, these compressive fluctuations

  2. Kondo Resonance in a Mesoscopic Ring Coupled to a Quantum Dot: Exact Results for the Aharonov-Bohm-Casher Effects

    SciTech Connect (OSTI)

    Eckle, H.-P.; Johannesson, H.; Stafford, C. A.

    2001-07-02

    We study the persistent currents induced by both the Aharonov-Bohm and Aharonov-Casher effects in a one-dimensional mesoscopic ring coupled to a sidebranch quantum dot at Kondo resonance. For privileged values of the Aharonov-Bohm-Casher fluxes, the problem can be mapped onto an integrable model, exactly solvable by a Bethe ansatz. In the case of a pure magnetic Aharonov-Bohm flux, we find that the presence of the quantum dot has no effect on the persistent current. In contrast, the Kondo resonance interferes with the spin-dependent Aharonov-Casher effect to induce a current which, in the strong-coupling limit, is independent of the number of electrons in the ring.

  3. Influence of the vacuum-lunar regolith interface on the generation of radio emission by a cascade shower from an ultrahigh-energy particle

    SciTech Connect (OSTI)

    Filonenko, A. D.

    2012-03-15

    We present the results of our calculation of the radio emission field produced by an electron-photon shower from an ultrahigh-energy particle under the surface of the Moon. We consider two cases of cascade propagation: the first in the lunar regolith-vacuum direction at small angles to the interface; and the second in the opposite direction when the particle generates a cascade almost immediately after it has crossed the vacuum-regolith interface. To calculate the relative energy density of the emission emerged at the surface, we have used the method of decomposing spherical waves into plane ones. The intensity of the refracted waves for high frequencies has been found to depend strongly on the shower inclination angle.

  4. Matrix Metalloproteinase Stromelysin-1 Triggers a Cascade of Molecular Alterations that leads to stable epithelial-to-Mesenchymal Conversion and a Premalignant Phenotype in Mammary Epithelial Cells

    SciTech Connect (OSTI)

    Lochter, A.; Galosy, S.; Muschler, J.; Freedman, N.; Werb, Z.; Bissell, M.J.

    1997-08-11

    Matrix metalloproteinases (MMPs) regulate ductal morphogenesis, apoptosis, and neoplastic progression in mammary epithelial cells. To elucidate the direct effects of MMPs on mammary epithelium, we generated functionally normal cells expressing an inducible autoactivating stromelysin-1 (SL-1) transgene. Induction of SL-1 expression resulted in cleavage of E-cadherin, and triggered progressive phenotypic conversion characterized by disappearance of E-cadherin and catenins from cell-cell contacts, downregulation of cytokeratins, upregulation of vimentin, induction of keratinocyte growth factor expression and activation, and upregulation of endogenous MMPs. Cells expressing SL-1 were unable to undergo lactogenic differentiation and became invasive. Once initiated, this phenotypic conversion was essentially stable, and progressed even in the absence of continued SL-1 expression. These observations demonstrate that inappropriate expression of SL-1 initiates a cascade of events that may represent a coordinated program leading to loss of the differentiated epithelial phenotype and gain of some characteristics of tumor cells. Our data provide novel insights into how MMPs function in development and neoplastic conversion.

  5. Long wave infrared cavity-enhanced sensors using quantum cascade lasers

    SciTech Connect (OSTI)

    Taubman, Matthew S.; Scott, David C.; Myers, Tanya L.; Cannon, Bret D.

    2005-12-30

    Quantum cascade lasers (QCLs) are becoming well known as convenient and stable semiconductor laser sources operating in the mid- to long-wave infrared, and are able to be fabricated to operate virtually anywhere in the 3.5 to 25 micron region. This makes them an ideal choice for infrared chemical sensing, a topic of great interest at present, spanning at least three critical areas: national security, environmental monitoring and protection, and the early diagnosis of disease through breath analysis. There are many different laser-based spectroscopic chemical sensor architectures in use today, from simple direct detection through to more complex and highly sensitive systems. Many current sensor needs can be met by combining QCLs and appropriate sensor architectures, those needs ranging from UAV-mounted surveillance systems, through to larger ultra-sensitive systems for airport security. In this paper we provide an overview of various laser-based spectroscopic sensing techniques, pointing out advantages and disadvantages of each. As part of this process, we include our own results and observations for techniques under development at PNNL. We also present the latest performance of our ultra-quiet QCL control electronics now being commercialized, and explore how using optimized supporting electronics enables increased sensor performance and decreased sensor footprint for given applications.

  6. Transport-reaction model for defect and carrier behavior within displacement cascades in gallium arsenide

    SciTech Connect (OSTI)

    Wampler, William R.; Myers, Samuel M.

    2014-02-01

    A model is presented for recombination of charge carriers at displacement damage in gallium arsenide, which includes clustering of the defects in atomic displacement cascades produced by neutron or ion irradiation. The carrier recombination model is based on an atomistic description of capture and emission of carriers by the defects with time evolution resulting from the migration and reaction of the defects. The physics and equations on which the model is based are presented, along with details of the numerical methods used for their solution. The model uses a continuum description of diffusion, field-drift and reaction of carriers and defects within a representative spherically symmetric cluster. The initial radial defect profiles within the cluster were chosen through pair-correlation-function analysis of the spatial distribution of defects obtained from the binary-collision code MARLOWE, using recoil energies for fission neutrons. Charging of the defects can produce high electric fields within the cluster which may influence transport and reaction of carriers and defects, and which may enhance carrier recombination through band-to-trap tunneling. Properties of the defects are discussed and values for their parameters are given, many of which were obtained from density functional theory. The model provides a basis for predicting the transient response of III-V heterojunction bipolar transistors to pulsed neutron irradiation.

  7. Results of Large-Scale Testing on Effects of Anti-Foam Agent on Gas Retention and Release

    SciTech Connect (OSTI)

    Stewart, Charles W.; Guzman-Leong, Consuelo E.; Arm, Stuart T.; Butcher, Mark G.; Golovich, Elizabeth C.; Jagoda, Lynette K.; Park, Walter R.; Slaugh, Ryan W.; Su, Yin-Fong; Wend, Christopher F.; Mahoney, Lenna A.; Alzheimer, James M.; Bailey, Jeffrey A.; Cooley, Scott K.; Hurley, David E.; Johnson, Christian D.; Reid, Larry D.; Smith, Harry D.; Wells, Beric E.; Yokuda, Satoru T.

    2008-01-03

    The U.S. Department of Energy (DOE) Office of River Protections Waste Treatment Plant (WTP) will process and treat radioactive waste that is stored in tanks at the Hanford Site. The waste treatment process in the pretreatment facility will mix both Newtonian and non-Newtonian slurries in large process tanks. Process vessels mixing non-Newtonian slurries will use pulse jet mixers (PJMs), air sparging, and recirculation pumps. An anti-foam agent (AFA) will be added to the process streams to prevent surface foaming, but may also increase gas holdup and retention within the slurry. The work described in this report addresses gas retention and release in simulants with AFA through testing and analytical studies. Gas holdup and release tests were conducted in a 1/4-scale replica of the lag storage vessel operated in the Pacific Northwest National Laboratory (PNNL) Applied Process Engineering Laboratory using a kaolin/bentonite clay and AZ-101 HLW chemical simulant with non-Newtonian rheological properties representative of actual waste slurries. Additional tests were performed in a small-scale mixing vessel in the PNNL Physical Sciences Building using liquids and slurries representing major components of typical WTP waste streams. Analytical studies were directed at discovering how the effect of AFA might depend on gas composition and predicting the effect of AFA on gas retention and release in the full-scale plant, including the effects of mass transfer to the sparge air. The work at PNNL was part of a larger program that included tests conducted at Savannah River National Laboratory (SRNL) that is being reported separately. SRNL conducted gas holdup tests in a small-scale mixing vessel using the AZ-101 high-level waste (HLW) chemical simulant to investigate the effects of different AFAs, their components, and of adding noble metals. Full-scale, single-sparger mass transfer tests were also conducted at SRNL in water and AZ-101 HLW simulant to provide data for PNNL

  8. Geology and geothermal resources of the Santiam Pass area of the Oregon Cascade Range, Deschutes, Jefferson and Linn Counties, Oregon. Final report

    SciTech Connect (OSTI)

    Hill, B.E.

    1992-10-01

    This open-file report presents the results of the Santiam Pass drilling program. The first phase of this program was to compile all available geological, geophysical and geothermal data for the Santiam Pass area and select a drill site on the basis of these data (see Priest and others, 1987a), A summary of the drilling operations and costs associated with the project are presented in chapter 1 by Hill and Benoit. An Overview of the geology of the Santiam Pass area is presented by Hill and Priest in chapter 2. Geologic mapping and isotopic age determinations in the Santiam Pass-Mount Jefferson area completed since 1987 are summarized in chapter 2. One of the more important conclusions reached in chapter 2 is that a minimum of 2 km vertical displacement has occurred in the High Cascade graben in the Santiam Pass area. The petrology of the Santiam Pass drill core is presented by Hill in chapter 3. Most of the major volcanic units in the core have been analyzed for major, minor, and trace element abundances and have been studied petrographically. Three K-Ar ages are interpreted in conjunction with the magnetostratigraphy of the core to show that the oldest rocks in the core are approximately 1.8 Ma. Geothermal and geophysical data collected from the Santiam Pass well are presented by Blackwell in chapter 4. The Santiam Pass well failed to penetrate beneath the zone of lateral groundwater flow associated with highly permeable Quaternary volcanic rocks. Calculated geothermal gradients range from about 50{degree}C/km at depth 700-900 m, to roughly 110{degree}C/km from 900 m to the bottom of the well at 929 m. Heat-flow values for the bottom part of the hole bracket the regional average for the High Cascades. Blackwell concludes that heat flow along the High Cascades axis is equal to or higher than along the western edge of the High Cascades.

  9. Excitonic enhancement of nonradiative energy transfer to bulk silicon with the hybridization of cascaded quantum dots

    SciTech Connect (OSTI)

    Yeltik, Aydan; Guzelturk, Burak; Akhavan, Shahab; Ludwig Hernandez-Martinez, Pedro; Volkan Demir, Hilmi

    2013-12-23

    We report enhanced sensitization of silicon through nonradiative energy transfer (NRET) of the excitons in an energy-gradient structure composed of a cascaded bilayer of green- and red-emitting CdTe quantum dots (QDs) on bulk silicon. Here NRET dynamics were systematically investigated comparatively for the cascaded energy-gradient and mono-dispersed QD structures at room temperature. We show experimentally that NRET from the QD layer into silicon is enhanced by 40% in the case of an energy-gradient cascaded structure as compared to the mono-dispersed structures, which is in agreement with the theoretical analysis based on the excited state population-depopulation dynamics of the QDs.

  10. CASCADED USES OF GEOTHERMAL ENERGY Paul Brophy EGS, Inc. & GRC President

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

    CASCADED USES OF GEOTHERMAL ENERGY Paul Brophy EGS, Inc. & GRC President John W. Lund Emeritus Geo-Heat Center Tonya "Toni" Boyd Emeritus Geo-Heat Center INTRODUCTION * Cascading is not a new concept * Combining heat and/or power provides - Increased net efficiency - Improved economics * Thermodynamics of geothermal plants - Lower than conventional plants - Due to lower working fluid temperatures * (550 o C vs <200 o C - 1,200 vs <390°F) INTRODUCTION 2 * 1 MWe geothermal

  11. First and second order approximations to stage numbers in multicomponent enrichment cascades

    SciTech Connect (OSTI)

    Scopatz, A.

    2013-07-01

    This paper describes closed form, Taylor series approximations to the number product stages in a multicomponent enrichment cascade. Such closed form approximations are required when a symbolic, rather than a numeric, algorithm is used to compute the optimal cascade state. Both first and second order approximations were implemented. The first order solution was found to be grossly incorrect, having the wrong functional form over the entire domain. On the other hand, the second order solution shows excellent agreement with the 'true' solution over the domain of interest. An implementation of the symbolic, second order solver is available in the free and open source PyNE library. (authors)

  12. Simulation of Cascaded Longitudinal-Space-Charge Amplifier at the Fermilab Accelerator Science & Technology (Fast) Facility

    SciTech Connect (OSTI)

    Halavanau, A.; Piot, P.

    2015-12-01

    Cascaded Longitudinal Space Charge Amplifiers (LSCA) have been proposed as a mechanism to generate density modulation over a board spectral range. The scheme has been recently demonstrated in the optical regime and has confirmed the production of broadband optical radiation. In this paper we investigate, via numerical simulations, the performance of a cascaded LSCA beamline at the Fermilab Accelerator Science & Technology (FAST) facility to produce broadband ultraviolet radiation. Our studies are carried out using elegant with included tree-based grid-less space charge algorithm.

  13. ARRA: Reconfiguring Power Systems to Minimize Cascading Failures - Models and Algorithms

    SciTech Connect (OSTI)

    Dobson, Ian; Hiskens, Ian; Linderoth, Jeffrey; Wright, Stephen

    2013-12-16

    Building on models of electrical power systems, and on powerful mathematical techniques including optimization, model predictive control, and simluation, this project investigated important issues related to the stable operation of power grids. A topic of particular focus was cascading failures of the power grid: simulation, quantification, mitigation, and control. We also analyzed the vulnerability of networks to component failures, and the design of networks that are responsive to and robust to such failures. Numerous other related topics were investigated, including energy hubs and cascading stall of induction machines

  14. Investigation of the thermal regime and geologic history of the Cascade volcanic arc: First phase of a program for scientific drilling in the Cascade Range

    SciTech Connect (OSTI)

    Priest, G.R.

    1987-01-01

    A phased, multihole drilling program with associated science is proposed as a means of furthering our understanding of the thermal regime and geologic history of the Cascade Range of Washington, Oregon, and northern California. The information obtained from drilling and ancillary geological and geophysical investigations will contribute to our knowledge in the following general areas: (1) the magnitude of the regional background heat flow of parts of the Quaternary volcanic belt dominated by the most abundant volcanic rock types, basalt and basaltic andesite; (2) the nature of the heat source responsible for the regional heat-flow anomaly; (3) the characteristics of the regional hydrothermal and cold-water circulation; the rates of volcanism for comparison with models for the rate and direction of plate convergence of the Cascades; (5) the history of deformation and volcanism in the volcanic arc that can be related to subduction; (6) the present-day stress regime of the volcanic arc and the relation of these stresses to plate interactions and possible large earthquakes; and the current geometry of the subducted oceanic plate below the Cascade Range and the relationship of the plate to the distribution of heat flow, Quaternary volcanism, and Quaternary deformation. Phase I research will be directed toward a detailed investigation of the Santiam Pass segment. In concert with the Santiam Pass research, a detailed study of the nearby Breitenbush Hot Springs area is also recommended as a component of Phase I. The object of the Breitenbush research is to study one of the hottest known Cascade hydrothermal systems, which coincidentally also has a good geological and geophysical data base. A coordinated program of drilling, sampling, subsurface measurements, and surface surveys will be associated with the drilling of several holes.

  15. Effect of Fuel Wobbe Number on Pollutant Emissions from Advanced Technology Residential Water Heaters: Results of Controlled Experiments

    SciTech Connect (OSTI)

    Rapp, Vi H.; Singer, Brett C.

    2014-03-01

    The research summarized in this report is part of a larger effort to evaluate the potential air quality impacts of using liquefied natural gas in California. A difference of potential importance between many liquefied natural gas blends and the natural gas blends that have been distributed in California in recent years is the higher Wobbe number of liquefied natural gas. Wobbe number is a measure of the energy delivery rate for appliances that use orifice- or pressure-based fuel metering. The effect of Wobbe number on pollutant emissions from residential water heaters was evaluated in controlled experiments. Experiments were conducted on eight storage water heaters, including five with “ultra low-NO{sub X}” burners, and four on-demand (tankless) water heaters, all of which featured ultra low-NO{sub X} burners. Pollutant emissions were quantified as air-free concentrations in the appliance flue and fuel-based emission factors in units of nanogram of pollutant emitter per joule of fuel energy consumed. Emissions were measured for carbon monoxide (CO), nitrogen oxides (NO{sub X}), nitrogen oxide (NO), formaldehyde and acetaldehyde as the water heaters were operated through defined operating cycles using fuels with varying Wobbe number. The reference fuel was Northern California line gas with Wobbe number ranging from 1344 to 1365. Test fuels had Wobbe numbers of 1360, 1390 and 1420. The most prominent finding was an increase in NO{sub X} emissions with increasing Wobbe number: all five of the ultra low-NO{sub X} storage water heaters and two of the four ultra low-NO{sub X} on-demand water heaters had statistically discernible (p<0.10) increases in NO{sub X} with fuel Wobbe number. The largest percentage increases occurred for the ultra low-NO{sub X} water heaters. There was a discernible change in CO emissions with Wobbe number for all four of the on-demand devices tested. The on-demand water heater with the highest CO emissions also had the largest CO increase

  16. Femtosecond measurements of near-infrared pulse induced mid-infrared transmission modulation of quantum cascade lasers

    SciTech Connect (OSTI)

    Cai, Hong; Liu, Sheng; Lalanne, Elaine; Guo, Dingkai; Chen, Xing; Choa, Fow-Sen; Wang, Xiaojun; Johnson, Anthony M.

    2014-05-26

    We temporally resolved the ultrafast mid-infrared transmission modulation of quantum cascade lasers (QCLs) using a near-infrared pump/mid-infrared probe technique at room temperature. Two different femtosecond wavelength pumps were used with photon energy above and below the quantum well (QW) bandgap. The shorter wavelength pump modulates the mid-infrared probe transmission through interband transition assisted mechanisms, resulting in a high transmission modulation depth and several nanoseconds recovery lifetime. In contrast, pumping with a photon energy below the QW bandgap induces a smaller transmission modulation depth but much faster (several picoseconds) recovery lifetime, attributed to intersubband transition assisted mechanisms. The latter ultrafast modulation (>60?GHz) could provide a potential way to realize fast QCL based free space optical communication.

  17. Atomistic Simulations of Displacement Cascades in Fused Silica: It is Compared with Different Concentration of H in the Bulk

    SciTech Connect (OSTI)

    Mota, Fernando; Perlado, Jose Manuel; Caturla, Maria Jose; Ibarra, Angel; Molla, Joaquin

    2008-07-01

    Amorphous Silica is one of candidate materials for both final focusing optics of lasers for NIF and future inertial fusion reactors and diagnostics of the Safety and Control Systems of the ITER machine as well as DEMO magnetic fusion reactors. In operation, these materials will be exposed to high neutron irradiation fluxes and it can result in point defect and vary the optical absorption, that is, degradation of the optical properties. In this paper we present molecular dynamic simulation of displacement cascade due to energetic recoils in amorphous silica without hydrogen atoms and with 1% of hydrogen atoms trying to identify defects formation. We have made a statistics of the different kind of defects at different energy of primary knock-on atoms (PKA). The range of studied PKA energies are from 400 eV to 3.5 keV and it is made to both component of this material Silicon and Oxygen. (authors)

  18. Explosive Results

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

    Explosive National Security Science Latest Issue:April 2016 past issues All Issues » submit Explosive Results Scientists at Los Alamos are solving national security challenges, from the threat of toothpaste-tube bombs on airliners to ensuring the safety of our nuclear stockpile. April 1, 2016 Explosive Results To test whether a travel-toothpaste-tube-sized bomb could bring down an airliner, Los Alamos scientists tried to blow a hole through half-inch-thick aircraft-grade aluminum using an

  19. Phase 1 Feasibility Study, Canby Cascaded Geothermal Project, April 2, 2013

    SciTech Connect (OSTI)

    Merrick, Dale E

    2013-04-02

    A small community in Northern California is attempting to use a local geothermal resource to generate electrical power and cascade residual energy to an existing geothermal district heating system, greenhouse, and future fish farm and subsequent reinjection into the geothermal aquifer, creating a net-zero energy community, not including transportation.

  20. A Ka-band TM{sub 02} mode relativistic backward wave oscillator with cascaded resonators

    SciTech Connect (OSTI)

    Teng, Yan; Cao, Yinbin; Song, Zhimin; Ye, Hu; Shi, Yanchao; Chen, Changhua; Sun, Jun

    2014-12-15

    By combining the Cerenkov-type generator with the cascaded resonators, this paper proposes a Ka-band relativistic backward wave oscillator operating under the guide magnetic field 1.0 T with high power handling capability and high conversion efficiency. It is found that TM{sub 02} can be selected as the operation mode in order to increase the power handling capability and provide sufficient coupling with the electron beam. In slow wave structure (SWS), ripples composed of semicircle on top of the rectangle enhance the wave-beam interaction and decrease the intensity of the electric field on the metallic surface. Taking advantage of the resonator cascades, the output power and the conversion efficiency are promoted greatly. The front cascaded resonators efficiently prevent the power generated in SWS from leaking into the diode region, and quicken the startup of the oscillation due to the premodulation of the beam. However, the post cascade slightly postpones the startup because of the further energy extraction from the electron beam. The numerical simulation shows that generation with power 514 MW and efficiency 41% is obtained under the diode voltage 520 kV and current 2.4 kA. And the microwave with the pure frequency spectrum of 29.35 GHz radiates in the pure TM{sub 01} mode.

  1. On the cascade capture of electrons at donors in GaAs quantum wells

    SciTech Connect (OSTI)

    Aleshkin, V. Ya.

    2015-09-15

    The impact parameter for the cascade capture of electrons at a charged donor in a GaAs quantum well is calculated. A simple approximate analytical expression for the impact parameter is suggested. The temperature dependence of the impact parameter for the case of electron scattering by the piezoelectric potential of acoustic phonons is determined.

  2. Cascaded die mountings with spring-loaded contact-bond options

    DOE Patents [OSTI]

    Hsu, John S.; Adams, Donald J.; Su, Gui-Jia; Marlino, Laura D.; Ayers, Curtis W.; Coomer, Chester

    2005-08-16

    A cascaded die mounting device and method using spring contacts for die attachment, with or without metallic bonds between the contacts and the dies, is disclosed. One embodiment is for the direct refrigerant cooling of an inverter/converter carrying higher power levels than most of the low power circuits previously taught, and does not require using a heat sink.

  3. Method of making cascaded die mountings with springs-loaded contact-bond options

    DOE Patents [OSTI]

    Hsu, John S.; Adams, Donald J.; Su, Gui-Jia; Marlino, Laura D.; Ayers, Curtis W.; Coomer, Chester

    2007-06-19

    A cascaded die mounting device and method using spring contacts for die attachment, with or without metallic bonds between the contacts and the dies, is disclosed. One embodiment is for the direct refrigerant cooling of an inverter/converter carrying higher power levels than most of the low power circuits previously taught, and does not require using a heat sink.

  4. Implications of volcano-tectonic patterns in the Oregon cascades for geothermal exploration

    SciTech Connect (OSTI)

    Priest, G.R.; Woller, N.M.; Black, G.L.; Evans, S.H.; Ruscetta, C.A.

    1982-07-01

    Basin and Range and subduction-related processes may have combined to produce voluminous mafic volcanism and very high heat flow in the central Oregon High Cascades during the last 9 m.y. This high rate of volcanism and heat flow prevails south of the Clackamas River right lateral wrench fault zone. South of this zone the volume of mafic volcanic rocks less than 9 m.y. old increases abruptly and regional heat flow increases by at least 20 mW/m/sup 2/. A similar, but larger, increase in volcanism and heat flow characterizes the transition from the Blue Mountain block to the Basin and Range Province at the Brothers right lateral wrench fault zone. A significant amount of the 0 to 9 m.y.B.P. mafic volcanic rock in the Cascades is basalt, with one or all of the following attributes of contemporaneous basalts of the Brothers Fault Zone-Basin and Range province: (1) anomalously high alkali and iron content relative to normal calc-alkaline rocks; (2) diktytaxitic texture with titaniferous groundmass clinopyroxene. This suggests a common petrogenesis for these basalts, perhaps from partial melting related to Basin and Range spreading. Potential operation of two partial melting mechanisms in the Oregon High Cascades may cause a high rate of magmatic heat transferral from mantle regions relative to transferral in the Basin and Range. This means that the High Cascades probably has the highest geothermal potential of any province in Oregon, especially where intercepted by youthful faults. North-south faults which bound a large area of Pliocene to Pleistocene subsidence along the High Cascade axis are good exploration targets. Silicic volcanism at the Brothers Fault zone intersection makes this the best exploration target in Oregon.

  5. Nonlinear Trivelpiece--Gould waves: Recurrence, harmonic cascade, and sidebands

    SciTech Connect (OSTI)

    Cabral, J.A.C.; Lapao, L.M.; Mendonca, J.T. )

    1993-03-01

    A theoretical and experimental study of Trivelpiece--Gould waves propagating in a magnetized plasma column is presented in this paper. In the experiments, these waves are excited by a radio frequency (rf) source, which also serves to create the plasma. Observation of nonlinear effects includes space and time recurrence effects, a wave spectrum containing a large number (up to 25) harmonics, and low-frequency sidebands. The theoretical model explains the recurrence effects as a consequence of multiple nonlinear interactions between the fundamental wave and its harmonics. A good agreement is found between theory and the experiments.

  6. 4-wave mixing for phase-matching free nonlinear optics in quantum cascade structures : LDRD 08-0346 final report.

    SciTech Connect (OSTI)

    Chow, Weng Wah; Wanke, Michael Clement; Allen, Dan G.; Yang, Zhenshan; Waldmueller, Ines

    2010-10-01

    Optical nonlinearities and quantum coherences have the potential to enable efficient, high-temperature generation of coherent THz radiation. This LDRD proposal involves the exploration of the underlying physics using intersubband transitions in a quantum cascade structure. Success in the device physics aspect will give Sandia the state-of-the-art technology for high-temperature THz quantum cascade lasers. These lasers are useful for imaging and spectroscopy in medicine and national defense. Success may have other far-reaching consequences. Results from the in-depth study of coherences, dephasing and dynamics will eventually impact the fields of quantum computing, optical communication and cryptology, especially if we are successful in demonstrating entangled photons or slow light. An even farther reaching development is if we can show that the QC nanostructure, with its discrete atom-like intersubband resonances, can replace the atom in quantum optics experiments. Having such an 'artificial atom' will greatly improve flexibility and preciseness in experiments, thereby enhancing the discovery of new physics. This is because we will no longer be constrained by what natural can provide. Rather, one will be able to tailor transition energies and optical matrix elements to enhance the physics of interest. This report summarizes a 3-year LDRD program at Sandia National Laboratories exploring optical nonlinearities in intersubband devices. Experimental and theoretical investigations were made to develop a fundamental understanding of light-matter interaction in a semiconductor system and to explore how this understanding can be used to develop mid-IR to THz emitters and nonclassical light sources.

  7. A widely tunable 10-μm quantum cascade laser phase-locked to a state-of-the-art mid-infrared reference for precision molecular spectroscopy

    SciTech Connect (OSTI)

    Sow, P. L. T.; Mejri, S.; Tokunaga, S. K.; Lopez, O.; Argence, B.; Chardonnet, C.; Darquié, B.; Goncharov, A.; Amy-Klein, A.; Daussy, C.

    2014-06-30

    We report the coherent phase-locking of a quantum cascade laser (QCL) at 10-μm to the secondary frequency standard of this spectral region, a CO{sub 2} laser stabilized on a saturated absorption line of OsO{sub 4}. The stability and accuracy of the standard are transferred to the QCL resulting in a line width of the order of 10 Hz, and leading to the narrowest QCL to date. The locked QCL is then used to perform absorption spectroscopy spanning 6 GHz of NH{sub 3} and methyltrioxorhenium, two species of interest for applications in precision measurements.

  8. Spectral modification of the laser emission of a terahertz quantum cascade laser induced by broad-band double pulse injection seeding

    SciTech Connect (OSTI)

    Markmann, Sergej Nong, Hanond Hekmat, Negar; Jukam, Nathan; Pal, Shovon; Scholz, Sven; Kukharchyk, Nadezhda; Ludwig, Arne; Wieck, Andreas D.; Dhillon, Sukhdeep; Tignon, Jérôme; Marcadet, Xavier; Bock, Claudia; Kunze, Ulrich

    2015-09-14

    We demonstrate by injection seeding that the spectral emission of a terahertz (THz) quantum cascade laser (QCL) can be modified with broad-band THz pulses whose bandwidths are greater than the QCL bandwidth. Two broad-band THz pulses delayed in time imprint a modulation on the single THz pulse spectrum. The resulting spectrum is used to injection seed the THz QCL. By varying the time delay between the THz pulses, the amplitude distribution of the QCL longitudinal modes is modified. By applying this approach, the QCL emission is reversibly switched from multi-mode to single mode emission.

  9. Cascades from nu_E above 1020 eV

    SciTech Connect (OSTI)

    Klein, Spencer R.

    2004-12-21

    At very high energies, the Landau-Pomeranchuk-Migdal effect reduces the cross sections for electron bremsstrahlung and photon e{sup +}e{sup -} pair production. The fractional electron energy loss and pair production cross sections drop as the energy increases. In contrast, the cross sections for photonuclear interactions grow with energy. In solids and liquids, at energies above 10{sup 20} eV, photonuclear reactions dominate, and showers that originate as photons or electrons quickly become hadronic showers. These electron-initiated hadronic showers are much shorter (due to the absence of the LPM effect), but wider than purely electromagnetic showers would be. This change in shape alters the spectrum of the electromagnetic and acoustic radiation emitted from the shower. These alterations have important implications for existing and planned searches for radiation from u{sub e} induced showers above 10{sup 20} eV, and some existing limits should be reevaluated.

  10. Assessment of effectiveness of geologic isolation systems. Geologic-simulation model for a hypothetical site in the Columbia Plateau. Volume 2: results

    SciTech Connect (OSTI)

    Foley, M.G.; Petrie, G.M.; Baldwin, A.J.; Craig, R.G.

    1982-06-01

    This report contains the input data and computer results for the Geologic Simulation Model. This model is described in detail in the following report: Petrie, G.M., et. al. 1981. Geologic Simulation Model for a Hypothetical Site in the Columbia Plateau, Pacific Northwest Laboratory, Richland, Washington. The Geologic Simulation Model is a quasi-deterministic process-response model which simulates, for a million years into the future, the development of the geologic and hydrologic systems of the ground-water basin containing the Pasco Basin. Effects of natural processes on the ground-water hydrologic system are modeled principally by rate equations. The combined effects and synergistic interactions of different processes are approximated by linear superposition of their effects during discrete time intervals in a stepwise-integration approach.

  11. Type-I cascaded quadratic soliton compression in lithium niobate: Compressing femtosecond pulses from high-power fiber lasers

    SciTech Connect (OSTI)

    Bache, Morten; Wise, Frank W.

    2010-05-15

    The output pulses of a commercial high-power femtosecond fiber laser or amplifier are typically around 300-500 fs with wavelengths of approximately 1030 nm and tens of microjoules of pulse energy. Here, we present a numerical study of cascaded quadratic soliton compression of such pulses in LiNbO{sub 3} using second-harmonic generation in a type-I phase-matching configuration. We find that because of competing cubic material nonlinearities, compression can only occur in the nonstationary regime, where group-velocity-mismatch-induced Raman-like nonlocal effects prevent compression to less than 100 fs. However, the strong group-velocity dispersion implies that the pulses can achieve moderate compression to durations of less than 130 fs in available crystal lengths. Most of the pulse energy is conserved because the compression is moderate. The effects of diffraction and spatial walk-off are addressed, and in particular the latter could become an issue when compressing such long crystals (around 10 cm long). We finally show that the second harmonic contains a short pulse locked to the pump and a long multi-picosecond red-shifted detrimental component. The latter is caused by the nonlocal effects in the nonstationary regime, but because it is strongly red-shifted to a position that can be predicted, we show that it can be removed using a bandpass filter, leaving a visible component of less than 100 fs at {lambda}=515 nm with excellent pulse quality.

  12. Turbulent Cascade at 1 AU in High Cross-Helicity Flows

    SciTech Connect (OSTI)

    Smith, Charles W.; Stawarz, Joshua E.; Vasquez, Bernard J.; Forman, Miriam A.; MacBride, Benjamin T.

    2009-11-13

    Analysis of the scaling of the mixed third moments of velocity and magnetic fluctuations in the solar wind plasma, and the energy cascade rates derived from the scaling, reveal a strong dependence on the amount of cross-field correlation between the velocity and magnetic field fluctuations. When the correlation is greater than about 75%, the cascade rate of the outward-propagating (majority) component, and of the total energy and the cross-helicity are surprisingly negative. This indicates a back transfer of energy from small to large scales within the inertial range of the dominant outward-propagating component. It is clear that the transfer of energy acts to reinforce the dominance of the outward-propagating (majority) component and may explain, in part, the persistent observations of large cross-field correlations that have been a defining aspect of solar wind physics for almost 40 years.

  13. Optimization of a low noise detection circuit for probing the structure of damage cascades with IBIC

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

    Auden, Elizabeth C.; Doyle, Barney L.; Bielejec, Edward; Vizkelethy, Gyorgy; Wampler, William R.

    2015-06-18

    Optimal detector / pre-amplifier combinations have been identified for the use of light ion IBIC (ion beam induced charge) to probe the physical structure of electrically active defects in damage cascades caused by heavy ion implantation. The ideal detector must have a sufficiently thin dead layer that incident ions will produce the majority of damage cascades in the depletion region of the detector rather than the dead layer. Detector and circuit noise must be low enough to detect the implantation of a single heavy ion as well as the decrease in the light ion IBIC signal caused by Shockley-Read-Hall recombinationmore » when the beam scans regions of the detector damaged by the heavy ion. The IBIC signals from three detectors irradiated with 750 keV He⁺ ions are measured with commercial and bespoke charge sensitive pre-amplifiers to identify the combination with the lowest noise.« less

  14. Validation of the Poisson Stochastic Radiative Transfer Model Against Cloud Cascade Models

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

    Poisson Stochastic Radiative Transfer Model Against Cloud Cascade Models T. B. Zhuravleva Institute of Atmospheric Optics Tomsk, Russia A. Marshak National Aeronautics and Space Administration Goddard Space Flight Center Greenbelt, Maryland Background Starting from a very simple stochastic cloud model by Mullamaa et al. (1972), several different stochastic models have been developed to describe radiative transfer regime in single-layer broken clouds (Kargin 1984; Titov 1990; Malvagi and

  15. Cascade Problems in Some Atomic Lifetime Measurements at a Heavy-Ion Storage Ring

    SciTech Connect (OSTI)

    Trabert, E; Hoffmann, J; Krantz, C; Wolf, A; Ishikawa, Y; Santana, J

    2008-10-09

    Lifetimes of 3s{sup 2}3p{sup k} ground configuration levels of Al-, Si-, P-, and S-like ions of Be, Co, and Ni have been measured at a heavy-ion storage ring. Some of the observed decay curves show strong evidence of cascade repopulation from specific 3d levels that feature lifetimes in the same multi-millisecond range as the levels of the ground configuration.

  16. Constraining the 6.05 MeV 0 + and 6.13 MeV 3 - Cascade Transitions...

    Office of Scientific and Technical Information (OSTI)

    Constraining the 6.05 MeV 0 + and 6.13 MeV 3 - Cascade Transitions in the C 12 ( , ) O 16 Reaction Using the Asymptotic Normalization Coefficients Citation Details ...

  17. Mid-Infrared Quantum-Dot Quantum Cascade Laser: A Theoretical Feasibility Study

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

    Michael, Stephan; Chow, Weng; Schneider, Hans

    2016-05-13

    In the framework of a microscopic model for intersubband gain from electrically pumped quantum-dot structures we investigate electrically pumped quantum-dots as active material for a mid-infrared quantum cascade laser. Our previous calculations have indicated that these structures could operate with reduced threshold current densities while also achieving a modal gain comparable to that of quantum well active materials. We study the influence of two important quantum-dot material parameters, here, namely inhomogeneous broadening and quantum-dot sheet density, on the performance of a proposed quantum cascade laser design. In terms of achieving a positive modal net gain, a high quantum-dot density canmore » compensate for moderately high inhomogeneous broadening, but at a cost of increased threshold current density. By minimizing quantum-dot density with presently achievable inhomogeneous broadening and total losses, significantly lower threshold densities than those reported in quantum-well quantum-cascade lasers are predicted by our theory.« less

  18. Parametric reflection upon cascade interaction of focused optical beams

    SciTech Connect (OSTI)

    Lobanov, V E; Sukhorukov, A P; Sukhorukova, A K

    2008-10-31

    The parametric reflection of a signal beam in the waist of the reference pump beam upon mismatched three-frequency interaction in a quadratically nonlinear medium is discussed. The critical angle of total internal reflection from the induced defocusing channel is found as a function of the beam waist parameters. It is shown that when the reference beam is focused, this angle increases and some distortions are introduced into the reflected wave due to a finite length of the waist. The modification of the cross section of a wave reflected from a convex parametric mirror is analysed. The optimal beam focusing geometry is found at which the distortions of the shape and divergence of the reflected wave are minimal. Under certain conditions, the signal wave also flows around a cylindrical inhomogeneity produced by the axially symmetric pump beam. The results of theoretical analysis and numerical simulation are in good agreement. (nonlinear optical phenomena)

  19. Late Cenozoic volcanism in the Lassen area, southernmost Cascade Range, California

    SciTech Connect (OSTI)

    Clynne, M.A.; Muffler, L.J.P.; Dalrymple, G.B. )

    1993-04-01

    Volcanism in the southernmost Cascade Range can be characterized on two scales. Regional volcanism is predominantly basaltic to andesitic, and hundreds of coalescing volcanoes of small volume (10[sup [minus]3] to 10[sup 1] km[sup 3]) with short lifetimes have built a broad platform. Superimposed on the regional volcanism are a few long-lived ([approximately]10[sup 6] years) much larger (>10 [sup 2] km[sup 3]) volcanic centers. Each of these larger centers consists of a basaltic-andesite to andesite composite cone and flanking silicic domes and flows. The evolution of these volcanic centers conforms to a generalized three-stage model during which a conspicuous edifice is constructed. Stages 1 and 2 comprise a dominantly andesitic composite cone; Stage 3 marks a change to dominantly silicic volcanism and is accompanied by development of a hydrothermal system in the permeable core of the andesitic composite cone. Subsequent fluvial and glacial erosion produces a caldera-like depression with a topographically high resistant rim of Stage 2 lavas surrounding the deeply eroded, hydrothermally altered core of the composite cone. Two types of basalt are recognized in the southernmost Cascades; medium-K calc-alkaline (CAB) and low-K olivine tholeiite (LKOT). CAB exhibits considerable geochemical diversity and is the parent magma for the volcanic-center lavas and the majority of the evolved regional lavas. LKOT is chemically homogeneous, and outcrops sporadically in association with extensional tectonics of the Basin and Range Province, and is related to Pleistocene encroachment of Basin-and-Range tectonics on the subduction-related volcanism of the Cascade Range.

  20. Detection and measurement of electroreflectance on quantum cascade laser device using Fourier transform infrared microscope

    SciTech Connect (OSTI)

    Enobio, Eli Christopher I.; Ohtani, Keita; Ohno, Yuzo; Ohno, Hideo

    2013-12-02

    We demonstrate the use of a Fourier Transform Infrared microscope system to detect and measure electroreflectance (ER) from mid-infrared quantum cascade laser (QCL) device. To characterize intersubband transition (ISBT) energies in a functioning QCL device, a microscope is used to focus the probe on the QCL cleaved mirror. The measured ER spectra exhibit resonance features associated to ISBTs under applied electric field in agreement with the numerical calculations and comparable to observed photocurrent, and emission peaks. The method demonstrates the potential as a characterization tool for QCL devices.

  1. Proton and gamma irradiation of Fabry-Perot quantum cascade lasers for space qualification

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

    Myers, Tanya L.; Cannon, Bret D.; Brauer, Carolyn S.; Hansen, Stewart; Crowther, Blake

    2015-01-20

    Fabry-Perot quantum cascade lasers (QCLs) were characterized following irradiation by high energy (64 MeV) protons and Cobalt-60 gamma rays. Seven QCLs were exposed to radiation dosages that are typical for a space mission in which the total accumulated dosages from both radiation sources varied from 20 krad(Si) to 46.3 krad(Si). The QCLs did not show any measurable changes in threshold current or slope efficiency suggesting the suitability of QCLs for use in space-based missions.

  2. Hyperspectral Microscopy of Explosives Particles Using an External Cavity Quantum Cascade Laser

    SciTech Connect (OSTI)

    Phillips, Mark C.; Bernacki, Bruce E.

    2012-12-26

    Using infrared hyperspectral imaging, we demonstrate microscopy of small particles of the explosives compounds RDX, tetryl, and PETN with near diffraction-limited performance. The custom microscope apparatus includes an external cavity quantum cascade laser illuminator scanned over its tuning range of 9.13-10.53 m in four seconds, coupled with a microbolometer focal plane array to record infrared transmission images. We use the hyperspectral microscopy technique to study the infrared absorption spectra of individual explosives particles, and demonstrate sub-nanogram detection limits.

  3. Integration of a terahertz quantum cascade laser with a hollow waveguide

    SciTech Connect (OSTI)

    Wanke, Michael C.; Nordquist, Christopher D.

    2012-07-03

    The present invention is directed to the integration of a quantum cascade laser with a hollow waveguide on a chip to improve both the beam pattern and manufacturability. By coupling the QCL output into a single-mode rectangular waveguide the radiation mode structure can be known and the propagation, manipulation, and broadcast of the QCL radiation can then be entirely controlled by well-established rectangular waveguide techniques. By controlling the impedance of the interface, enhanced functions, such as creating amplifiers, efficient coupling to external cavities, and increasing power output from metal-metal THz QCLs, are also enabled.

  4. Nano-optical observation of cascade switching in a parallel superconducting nanowire single photon detector

    SciTech Connect (OSTI)

    Heath, Robert M. Tanner, Michael G.; Casaburi, Alessandro; Hadfield, Robert H.; Webster, Mark G.; San Emeterio Alvarez, Lara; Jiang, Weitao; Barber, Zoe H.; Warburton, Richard J.

    2014-02-10

    The device physics of parallel-wire superconducting nanowire single photon detectors is based on a cascade process. Using nano-optical techniques and a parallel wire device with spatially separate pixels, we explicitly demonstrate the single- and multi-photon triggering regimes. We develop a model for describing efficiency of a detector operating in the arm-trigger regime. We investigate the timing response of the detector when illuminating a single pixel and two pixels. We see a change in the active area of the detector between the two regimes and find the two-pixel trigger regime to have a faster timing response than the one-pixel regime.

  5. Evaluating the coherence and time-domain profile of quantum cascade laser frequency combs

    SciTech Connect (OSTI)

    Burghoff, David; Yang, Yang; Hayton, Darren J.; Gao, Jian -Rong; Reno, John L.; Hu, Qing

    2015-01-01

    Recently, much attention has been focused on the generation of optical frequency combs from quantum cascade lasers. We discuss how fast detectors can be used to demonstrate the mutual coherence of such combs, and present an inequality that can be used to quantitatively evaluate their performance. We discuss several technical issues related to shifted wave interference Fourier Transform spectroscopy (SWIFTS), and show how such measurements can be used to elucidate the time-domain properties of such combs, showing that they can possess signatures of both frequency-modulation and amplitude-modulation.

  6. High field Q-slope and the baking effect: a brief review of recent experimental results and new data on Nb heat treatments

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

    Gianluigi Ciovati, Ganapati Myneni, Fred Stevie, Prateek Maheshwari, Dieter Griffis

    2010-02-01

    The performance of superconducting radio-frequency (SRF) cavities made of bulk Nb at high fields (peak surface magnetic field greater than about 90 mT) is characterized by exponentially increasing rf losses (high-field Q-slope), in the absence of field emission, which are often mitigated by low temperature (100-140 °C, 12-48 h) baking. In this contribution, recent experimental results and phenomenological models to explain this effect will be briefly reviewed. New experimental results on the high-field Q-slope will be presented for cavities that had been heat treated in a vacuum furnace at high temperature without subsequent chemical etching. These studies are aimed atmore » understanding the role of hydrogen on the high-field Q-slope and at the passivation of the Nb surface during heat treatment. Improvement of the cavity performances, particularly of the cavities’ quality factor, have been obtained following the high temperature heat-treatments, while SIMS surface analysis measurements on Nb samples treated with the cavities revealed significantly lower hydrogen concentration than for samples that followed standard cavity treatments.« less

  7. High field Q-slope and the baking effect: a brief review of recent experimental results and new data on Nb heat treatments

    SciTech Connect (OSTI)

    Gianluigi Ciovati, Ganapati Myneni, Fred Stevie, Prateek Maheshwari, Dieter Griffis

    2010-02-01

    The performance of superconducting radio-frequency (SRF) cavities made of bulk Nb at high fields (peak surface magnetic field greater than about 90 mT) is characterized by exponentially increasing rf losses (high-field Q-slope), in the absence of field emission, which are often mitigated by low temperature (100-140 C, 12-48 h) baking. In this contribution, recent experimental results and phenomenological models to explain this effect will be briefly reviewed. New experimental results on the high-field Q-slope will be presented for cavities that had been heat treated in a vacuum furnace at high temperature without subsequent chemical etching. These studies are aimed at understanding the role of hydrogen on the high-field Q-slope and at the passivation of the Nb surface during heat treatment. Improvement of the cavity performances, particularly of the cavities quality factor, have been obtained following the high temperature heat-treatments, while SIMS surface analysis measurements on Nb samples treated with the cavities revealed significantly lower hydrogen concentration than for samples that followed standard cavity treatments.

  8. Ion cascade acceleration from the interaction of a relativistic femtosecond laser pulse with a narrow thin target

    SciTech Connect (OSTI)

    He Feng; Xu Han; Tian Youwei; Yu Wei; Lu Peixiang; Li Ruxin

    2006-07-15

    Particle-in-cell simulations are performed to study the acceleration of ions due to the interaction of a relativistic femtosecond laser pulse with a narrow thin target. The numerical results show that ions can be accelerated in a cascade by two electrostatic fields if the width of the target is smaller than the laser beam waist. The first field is formed in front of the target by the central part of the laser beam, which pushes the electron layer inward. The major part of the abaxial laser energy propagates along the edges to the rear side of the target and pulls out some hot electrons from the edges of the target, which form another electrostatic field at the rear side of the target. The ions from the front surface are accelerated stepwise by these two electrostatic fields to high energies at the rear side of the target. The simulations show that the largest ion energy gain for a narrow target is about four times higher than in the case of a wide target.

  9. 21 THz quantum-cascade laser operating up to 144 K based on a scattering-assisted injection design

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

    Khanal, Sudeep; Reno, John L.; Kumar, Sushil

    2015-07-22

    A 2.1 THz quantum cascade laser (QCL) based on a scattering-assisted injection and resonant-phonon depopulation design scheme is demonstrated. The QCL is based on a four-well period implemented in the GaAs/Al0.15Ga0.85As material system. The QCL operates up to a heat-sink temperature of 144 K in pulsed-mode, which is considerably higher than that achieved for previously reported THz QCLs operating around the frequency of 2 THz. At 46 K, the threshold current-density was measured as ~745 A/cm2 with a peak-power output of ~10 mW. Electrically stable operation in a positive differential-resistance regime is achieved by a careful choice of design parameters.more » The results validate the robustness of scattering-assisted injection schemes for development of low-frequency (ν < 2.5 THz) QCLs.« less

  10. 21 THz quantum-cascade laser operating up to 144 K based on a scattering-assisted injection design

    SciTech Connect (OSTI)

    Khanal, Sudeep; Reno, John L.; Kumar, Sushil

    2015-07-22

    A 2.1 THz quantum cascade laser (QCL) based on a scattering-assisted injection and resonant-phonon depopulation design scheme is demonstrated. The QCL is based on a four-well period implemented in the GaAs/Al0.15Ga0.85As material system. The QCL operates up to a heat-sink temperature of 144 K in pulsed-mode, which is considerably higher than that achieved for previously reported THz QCLs operating around the frequency of 2 THz. At 46 K, the threshold current-density was measured as ~745 A/cm2 with a peak-power output of ~10 mW. Electrically stable operation in a positive differential-resistance regime is achieved by a careful choice of design parameters. The results validate the robustness of scattering-assisted injection schemes for development of low-frequency (ν < 2.5 THz) QCLs.

  11. The effect of turbulence on the stability of liquid jets and the resulting droplet size distributions. Third quarterly technical report, July 1, 1993--September 30, 1993

    SciTech Connect (OSTI)

    Mansour, A.; Chigier, N.

    1993-12-01

    Laminar and turbulent columns of liquids issuing from capillary tubes were studied in order to determine the effects of turbulence on the stability of liquid jets and to establish the influence of liquid turbulence on droplet size distributions after breakup. Two capillary tubes were chosen with diameters D{sub 1}=3.0mm and D{sub 2}=1.2mm; jet Reynolds numbers were 1000--30000, and 400--7200. For water injection into stagnant air, stability curve is bounded by a laminar portion, where a jet radius and {delta}{sub o} initial disturbance amplitude, and a fully developed turbulent portion characterized by high initial disturbance amplitude (ln(a/{delta}{sub o,T}) {approximately} 4.85). In the transition region, ln(a/{delta}{sub o}) is not single valued; it decreases with increasing Reynolds number. In absence of aerodynamic effects, turbulent jets are as stable as laminar jets. For this breakup mode turbulence propagates initial disturbances with amplitudes orders of magnitude larger than laminar jets ({delta}{sub o,T}=28{times}10{sup 6} {delta}{sub o,L}). Growth rates of initial disturbances are same for both laminar and turbulent columns with theoretical Weber values. Droplet size distribution is bi-modal; the number ratio of large (> D/2), to small (< D/2) droplets is 3 and independent of Reynolds number. For laminar flow optimum wavelength ({lambda}{sub opt}) corresponding to fastest growing disturbance is equal to 4.45D, exactly the theoretical Weber value. For turbulent flow conditions, the turbulent column segments. Typically, segments with lengths of one to several wavelengths, detach from the liquid jet. The long ligaments contract under the action of surface tension, resulting in droplet sizes larger than predicted by Rayleigh and Weber. For turbulent flow conditions, {lambda}{sub opt} = 9.2D, about 2 times the optimum Weber wavelength.

  12. Short-wavelength interband cascade infrared photodetectors operating above room temperature

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

    Lotfi, Hossein; Li, Lu; Lei, Lin; Jiang, Yuchao; Yang, Rui Q.; Klem, John F.; Johnson, Matthew B.

    2016-01-13

    High temperature operation (250–340 K) of short-wavelength interband cascade infrared photodetectors (ICIPs) with InAs/GaSb/Al0.2In0.8Sb/GaSb superlattice absorbers has been demonstrated with a 50% cutoff wavelength of 2.9 μm at 300 K. Two ICIP structures, one with two and the other with three stages, were designed and grown to explore this multiple-stage architecture. At λ = 2.1 μm, the two- and three-stage ICIPs had Johnson-noise-limited detectivities of 5.1 × 109 and 5.8 ×109 cm Hz1/2/W, respectively, at 300 K. The better device performance of the three-stage ICIP over the two-stage ICIP confirmed the advantage of more stages for this cascade architecture. Furthermore,more » an Arrhenius activation energy of 450 meV is extracted for the bulk resistance-area product, which indicates the dominance of the diffusion current at these high temperatures.« less

  13. Trace-gas sensing using the compliance voltage of an external cavity quantum cascade laser

    SciTech Connect (OSTI)

    Phillips, Mark C.; Taubman, Matthew S.

    2013-06-04

    Quantum cascade lasers (QCLs) are increasingly being used to detect, identify, and measure levels of trace gases in the air. External cavity QCLs (ECQCLs) provide a broadly-tunable infrared source to measure absorption spectra of chemicals and provide high detection sensitivity and identification confidence. Applications include detecting chemical warfare agents and toxic industrial chemicals, monitoring building air quality, measuring greenhouse gases for atmospheric research, monitoring and controlling industrial processes, analyzing chemicals in exhaled breath for medical diagnostics, and many more. Compact, portable trace gas sensors enable in-field operation in a wide range of platforms, including handheld units for use by first responders, fixed installations for monitoring air quality, and lightweight sensors for deployment in unmanned aerial vehicles (UAVs). We present experimental demonstration of a new chemical sensing technique based on intracavity absorption in an external cavity quantum cascade laser (ECQCL). This new technique eliminates the need for an infrared photodetector and gas cell by detecting the intracavity absorption spectrum in the compliance voltage of the laser device itself. To demonstrate and characterize the technique, we measure infrared absorption spectra of chemicals including water vapor and Freon-134a. Sub-ppm detection limits in one second are achieved, with the potential for increased sensitivity after further optimization. The technique enables development of handheld, high-sensitivity, and high-accuracy trace gas sensors for in-field use.

  14. Modelling on dynamics properties of a stationary argon cascaded arc plasma flows

    SciTech Connect (OSTI)

    Wei, G. D.; Qi, X.; Yang, L.

    2014-03-15

    The gas dynamics properties of a stationary arc plasma flows are studied through the numerical simulations. A two dimensional axis-symmetric turbulent magneto-hydrodynamic plasma model is developed with the commercial code ANSYS FLUENT. The reliable ?-? model is used to account for turbulence. In this paper, the plasma is assumed to be a fluid following NavierStokes equations, respecting local thermodynamic equilibrium, and described by only one temperature. Distributions of the pressure, velocity, temperature, density, and electric potential inside of thus cascaded arc are obtained for an arc current density of 10{sup 6}?A/m{sup 2}. The pressure inside the arc varies from 10{sup 5}?Pa to 100?Pa. The temperature at the arc axis can reach as high as 13?600?K. The electric potential drops uniformly along the axis with a magnitude of 160?V. In addition, distributions of the sonic velocity and Mach number are shown to describe supersonic behavior of thus cascaded arc, which have a good agreement with the analytical formula.

  15. CASCADER: An M-chain gas-phase radionuclide transport and fate model. Volume 4 -- Users guide to CASCADR9

    SciTech Connect (OSTI)

    Cawlfield, D.E.; Emer, D.F.; Lindstrom, F.T.; Shott, G.J.

    1993-09-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and/or dispersion. Additionally during the transport of parent and daughter radionuclides in soil, radionuclide decay may occur. This version of CASCADER called CASCADR9 starts with the concepts presented in volumes one and three of this series. For a proper understanding of how the model works, the reader should read volume one first. Also presented in this volume is a set of realistic scenarios for buried sources of radon gas, and the input and output file structure for CASCADER9.

  16. Electronic effects in high-energy radiation damage in tungsten

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

    Zarkadoula, Eva; Duffy, Dorothy M.; Nordlund, Kai; Seaton, M. A.; Todorov, I. T.; Weber, William J.; Trachenko, Kostya

    2015-01-01

    Even though the effects of the electronic excitations during high-energy radiation damage processes are not currently understood, it is shown that their role in the interaction of radiation with matter is important. We perform molecular dynamics simulations of high-energy collision cascades in bcc-tungsten using the coupled two-temperature molecular dynamics (2T-MD) model that incorporates both the effects of electronic stopping and electron–phonon interaction. We compare the combination of these effects on the induced damage with only the effect of electronic stopping, and conclude in several novel insights. In the 2T-MD model, the electron–phonon coupling results in less damage production in themore » molten region and in faster relaxation of the damage at short times. We show these two effects lead to a significantly smaller amount of the final damage at longer times.« less

  17. Review of Test Results

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

    4 Revision 1 Effective June 2008 Review of Test Results Prepared by Electric Transportation Applications Prepared by: _______________________________ Date:__________ Garrett P. Beauregard Approved by: _________________________________________________ Date: _______________ Donald B. Karner Procedure ETA-GAC004 Revision 1 2 ©2006 Electric Transportation Applications All Rights Reserved Table Of Contents 1 Objective

  18. A novel technique for blade-to-blade velocity measurements in a turbine cascade

    SciTech Connect (OSTI)

    Goss, L.P.; Post, M.E.; Trump, D.D.; Sarka, B.; Macarthur, C.D.

    1989-01-01

    A two-color particle-image velocimetry technique has been developed to study two-dimensional velocity flowfields. In the method, a green-colored laser sheet (formed by a doubled Nd-YAG laser) and a red-colored laser sheet (formed by a Nd:YAG-pumped dye laser) are used sequentially to expose the particle positions. Direction and particle displacement can be uniquely determined with the method because the green-particle image occurs before the red-particle image by a known time increment. The method is particularly useful for complex flowfields where the normal 180-deg directional ambiguity of single-color techniques can be troublesome. Velocity data for a turbine-cascade test section have been obtained with the two-color technique. 15 refs.

  19. Elastic strains at interfaces in InAs/AlSb multilayer structures for quantum cascade lasers

    SciTech Connect (OSTI)

    Nicolai, J.; Gatel, Ch.; Warot-Fonrose, B.; Ponchet, A.; Teissier, R.; Baranov, A. N.; Magen, C.

    2014-01-20

    InAs/AlSb multilayers similar to those used in quantum cascade lasers have been grown by molecular beam epitaxy on (001) InAs substrates. Elastic strain is investigated by high resolution transmission electron microscopy. Thin interfacial regions with lattice distortions significantly different from the strain of the AlSb layers themselves are revealed from the geometrical phase analysis. Strain profiles are qualitatively compared to the chemical contrast of high angle annular dark field images obtained by scanning transmission electron microscopy. The strain and chemical profiles are correlated with the growth sequences used to form the interfaces. Tensile strained AlAs-like interfaces tend to form predominantly due to the high thermal stability of AlAs. Strongly asymmetric interfaces, AlAs-rich and (Al, In)Sb, respectively, can also be achieved by using appropriate growth sequences.

  20. Reflection-Absorption Infrared Spectroscopy of Thin Films Using an External Cavity Quantum Cascade Laser

    SciTech Connect (OSTI)

    Phillips, Mark C.; Craig, Ian M.; Blake, Thomas A.

    2013-02-04

    We present experimental demonstrations using a broadly tunable external cavity quantum cascade laser (ECQCL) to perform Reflection-Absorption InfraRed Spectroscopy (RAIRS) of thin layers and residues on surfaces. The ECQCL compliance voltage was used to measure fluctuations in the ECQCL output power and improve the performance of the RAIRS measurements. Absorption spectra from self-assembled monolayers of a fluorinated alkane thiol and a thiol carboxylic acid were measured and compared with FTIR measurements. RAIRS spectra of the explosive compounds PETN, RDX, and tetryl deposited on gold substrates were also measured. Rapid measurement times and low noise were demonstrated, with < 1E-3 absorbance noise for a 10 second measurement time.

  1. Deformed rotational cascades in {sup 152}Dy: Further evidence for shape coexistence at high spin

    SciTech Connect (OSTI)

    Smith, M. B.; Department of Electronic Engineering and Physics, University of Paisley, Paisley PA1 2BE, ; Appelbe, D. E.; Twin, P. J.; Beausang, C. W.; Wright Nuclear Structure Laboratory, Yale University, 272 Whitney Avenue, New Haven, Connecticut 06520 ; Beck, F. A.; Bentley, M. A.; Cullen, D. M.; Curien, D.; Dagnall, P. J.; De France, G.

    2000-03-01

    Two new rotational bands have been observed in the {sup 152}Dy nucleus following experiments performed using the EUROGAM {gamma}-ray spectrometer. Several transitions have been observed that link these new bands into the known single-particle states. Using the Doppler shift attenuation method, the quadrupole moment of the previously-known rotational sequence has been measured. The value of Q{sub band}=3.85{+-}0.06 e b confirms the deformed nature of this cascade. The structures of the three bands are discussed in terms of the occupation of both paired and unpaired orbitals, and are found to be in good agreement with theoretical calculations. The observation of two new bands further extends the concept of shape coexistence in the {sup 152}Dy nucleus. (c) 2000 The American Physical Society.

  2. High detectivity short-wavelength II-VI quantum cascade detector

    SciTech Connect (OSTI)

    Ravikumar, Arvind P. Gmachl, Claire F.; Garcia, Thor A.; Tamargo, Maria C.; Jesus, Joel De

    2014-08-11

    We report on the experimental demonstration of a ZnCdSe/ZnCdMgSe-based short-wavelength photovoltaic Quantum Cascade Detector (QCD). The QCD operates in two spectral bands centered around 2.6??m and 3.6??m. Calibrated blackbody measurements yield a peak responsivity of 0.1?mA/W or 2400?V/W at 80?K, and a corresponding 300?K background radiation limited infrared performance detectivity (BLIP) of ?2.5??10{sup 10?}cm ?Hz/W. Comparison of background illuminated and dark current-voltage measurements demonstrates a BLIP temperature of 200?K. The device differential resistance-area product, decreases from about 10{sup 6} ? cm{sup 2} at 80?K to about 8000 ? cm{sup 2} at 300?K, indicative of the ultra-low Johnson noise in the detectors.

  3. Fuel cell and system for supplying electrolyte thereto utilizing cascade feed

    DOE Patents [OSTI]

    Feigenbaum, Haim

    1984-01-01

    An electrolyte distribution supply system for use with a fuel cell having a wicking medium for drawing electrolyte therein is formed by a set of containers of electrolyte joined to respective fuel cells or groups thereof in a stack of such cells. The electrolyte is separately stored so as to provide for electrical isolation between electrolytes of the individual cells or groups of cells of the stack. Individual storage compartments are coupled by individual tubes, the ends of the respective tubes terminating on the wicking medium in each of the respective fuel cells. The individual compartments are filled with electrolyte by allowing the compartments to overflow such as in a cascading fashion thereby maintaining the requisite depth of electrolyte in each of the storage compartments. The individual compartments can also contain packed carbon fibers to provide a three stage electrolyte distribution system.

  4. On-chip dual-comb based on quantum cascade laser frequency combs

    SciTech Connect (OSTI)

    Villares, G. Wolf, J.; Kazakov, D.; Süess, M. J.; Beck, M.; Faist, J.; Hugi, A.

    2015-12-21

    Dual-comb spectroscopy is emerging as an appealing application of mid-infrared frequency combs for high-resolution molecular spectroscopy, as it leverages on the unique coherence properties of frequency combs. Here, we present an on-chip dual-comb source based on mid-infrared quantum cascade laser frequency combs. Control of the combs repetition and offset frequencies is obtained by integrating micro-heaters next to each laser. We show that a full control of the dual-comb system is possible, by measuring a multi-heterodyne beating corresponding to an optical bandwidth of 32 cm{sup −1} centered at 1330 cm{sup −1} (7.52 μm), demonstrating that this device represents a critical step towards compact dual-comb systems.

  5. Design of cascaded low cost solar cell with CuO substrate

    SciTech Connect (OSTI)

    Samson, Mil'shtein; Anup, Pillai; Shiv, Sharma; Garo, Yessayan

    2013-12-04

    For many years the main focus of R and D in solar cells was the development of high-efficiency solar convertors. However with solar technology beginning to be a part of national grids and stand-alone power supplies for variety of individual customers, the emphasis has changed, namely, the cost per kilowatt- hour (kW-hr) started to be an important figure of merit. Although Si does dominate the market of solar convertors, this material has total cost of kilowatt-hour much higher than what the power grid is providing presently to customers. It is well known that the cost of raw semiconductor material is a major factor in formulation of the final cost of a solar cell. That motivated us to search and design a novel solar cell using cheap materials. The new p-i-n solar cell consists of hetero-structure cascade of materials with step by step decreasing energy gap. Since the lattice constant of these three materials do differ not more than 2%, the more expensive epitaxial fabrication methods can be used as well. It should be emphasized that designed solar cell is not a cascade of three solar cells connected in series. Our market study shows that Si solar panel which costs $250400 / m{sup 2} leads to a cost of $0.120.30 / kW-hr. To the contrary, CuO based solar cells with Cadmium compounds on top, would cost $100 / m{sup 2}. This will allow the novel solar cell to produce electricity at a cost of $0.060.08 / kW-hr.

  6. Use of external cavity quantum cascade laser compliance voltage in real-time trace gas sensing of multiple chemicals

    SciTech Connect (OSTI)

    Phillips, Mark C.; Taubman, Matthew S.; Kriesel, Jason M.

    2015-02-08

    We describe a prototype trace gas sensor designed for real-time detection of multiple chemicals. The sensor uses an external cavity quantum cascade laser (ECQCL) swept over its tuning range of 940-1075 cm-1 (9.30-10.7 µm) at a 10 Hz repetition rate.

  7. Fuel Sulfur Effects on a Medium-Duty Diesel Pick-Up with a NOx Adsorber, Diesel Particle Filter Emissions Control System: 2000-Hour Aging Results

    SciTech Connect (OSTI)

    Thornton, M.; Webb, C. C.; Weber, P. A.; Orban, J.; Slone, E.

    2006-05-01

    Discusses the emission results of a nitrogen oxide adsorber catalyst and a diesel particle filter in a medium-duty, diesel pick-up truck.

  8. Experimental and Numerical Investigation of Forming and Springback Behavior and the Resulting Effects on Industrial Application on a Structural Part in Mass Production

    SciTech Connect (OSTI)

    Prexl, A.; Hoffmann, H. [Institute of Metal Forming and Casting, Technische Universitaet Muenchen D-85747 Garching (Germany); Golle, M. [Institute of Metal Forming and Casting, Technische Universitaet Muenchen D-85747 Garching (Germany); Institute of Punching and Blanking, Pforzheim University, D-75175 Pforzheim (Germany); Kudrass, S.; Wahl, M. [AUDI AG, D-85045 Ingolstadt (Germany)

    2011-01-17

    Springback prediction and compensation is nowadays a widely recommended discipline in finite element modeling. Many researches have shown an improvement of the accuracy in prediction of springback using advanced modeling techniques, e.g. by including the Bauschinger effect. In this work different models were investigated in the commercial simulation program AutoForm for a large series production part, manufactured from the dual phase steel HC340XD. The work shows the differences between numerical drawbead models and geometrically modeled drawbeads. Furthermore, a sensitivity analysis was made for a reduced kinematic hardening model, implemented in the finite element program AutoForm.

  9. Frequency dependence of the maximum operating temperature for quantum-cascade lasers up to 5.4 THz

    SciTech Connect (OSTI)

    Wienold, M.; Röben, B.; Lü, X.; Rozas, G.; Schrottke, L.; Biermann, K.; Grahn, H. T.

    2015-11-16

    We report on the observation of an approximately linear reduction in the maximum operating temperature with an increasing emission frequency for terahertz quantum-cascade lasers between 4.2 and 5.4 THz. These lasers are based on the same design type, but vary in period length and barrier height for the cascade structure. The sample emitting at the highest frequency around 5.4 THz can be operated in pulsed mode up to 56 K. We identify an additional relaxation channel for electrons by longitudinal optical phonon scattering from the upper to the lower laser level and increasing optical losses toward higher frequencies as major processes, leading to the observed temperature behavior.

  10. Characterization of a Swept External Cavity Quantum Cascade Laser For Rapid Broadband Spectroscopy and Sensing

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

    Brumfield, Brian E.; Taubman, Matthew S.; Suter, Jonathan D.; Phillips, Mark C.

    2015-09-17

    The performance of a rapidly swept external cavity quantum cascade laser (ECQCL) system combined with an open-path Herriott cell was evaluated for time-resolved measurements of chemical species with broad and narrow absorption spectra. A spectral window spanning 1278 1390 cm-1 was acquired at a 200 Hz acquisition rate, corresponding to a tuning rate of 2x104 cm-1/s, with a spectral resolution of 0.2 cm-1. The capability of the ECQCL to measure morethe ECQCL system exhibited noise-equivalent absorption coefficients of 5x10-9 cm-1Hz-1/2. For a spectrum acquisition time of 5 ms, noise-equivalent concentrations (NEC) for N2O and F134A were measured to be 70 and 16 ppbv respectively, which improved to sub-ppbv levels with averaging to 100 s. Noise equivalent column densities of 0.64 and 0.25 in 1 sec are estimated for N2O and F134A.less