Sample records for boundary layer cap-mbl

  1. Clouds, Aerosol, and Precipitation in the Marine Boundary Layer: Analysis of Results from the ARM Mobile Facility Deployment to the Azores (2009/2010)

    SciTech Connect (OSTI)

    Wood, Robert [University of Washington, Dept of Atmos Sci

    2013-05-31T23:59:59.000Z

    The project focuses upon dataset analysis and synthesis of datasets from the AMF deployment entitled “Clouds, Aerosols, and Precipitation in the Marine Boundary Layer (CAP?MBL)” at Graciosa Island in the Azores. Wood is serving a PI for this AMF deployment.

  2. Clouds, Aerosols and Precipitation in the Marine Boundary Layer (CAP-MBL) AMF Deployment Graciosa Island, Azores, NE Atlantic Ocean May 2009-December 2010

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t zManufacturing:DOE NationalCommitteeof3 the Marine the

  3. METEOROLOGY 130 Boundary Layer Meteorology

    E-Print Network [OSTI]

    Clements, Craig

    4) Turbulence Kinetic Energy · TKE budget and terms · Stability concepts · Richardson number 5) Measuring the Boundary Layer · Balloons · Radars · Sodars · Towers (micrometeorology) · Measuring Turbulence Time Series Analysis 8) Similarity Theory and Turbulence Closure 9) Surface Energy Budgets 10) Special

  4. THE MARTIAN ATMOSPHERIC BOUNDARY LAYER

    E-Print Network [OSTI]

    Spiga, Aymeric

    THE MARTIAN ATMOSPHERIC BOUNDARY LAYER A. Petrosyan,1 B. Galperin,2 S. E. Larsen,3 S. R. Lewis,4 A [Haberle et al., 1993a; Larsen et al., 2002; Hinson et al., 2008]. At night, convection is inhibited

  5. Cyclone separator having boundary layer turbulence control

    DOE Patents [OSTI]

    Krishna, Coimbatore R. (Mt. Sinai, NY); Milau, Julius S. (Port Jefferson, NY)

    1985-01-01T23:59:59.000Z

    A cyclone separator including boundary layer turbulence control that is operable to prevent undue build-up of particulate material at selected critical areas on the separator walls, by selectively varying the fluid pressure at those areas to maintain the momentum of the vortex, thereby preventing particulate material from inducing turbulence in the boundary layer of the vortical fluid flow through the separator.

  6. ENTROPY BOUNDARY LAYERS FRANCK SUEUR

    E-Print Network [OSTI]

    Sueur, Franck

    on the boundary. These conditions are used in a reduction of the system. We construct BKW expansions at all order

  7. Energy transport using natural convection boundary layers

    SciTech Connect (OSTI)

    Anderson, R.

    1986-04-01T23:59:59.000Z

    Natural convection is one of the major modes of energy transport in passive solar buildings. There are two primary mechanisms for natural convection heat transport through an aperture between building zones: (1) bulk density differences created by temperature differences between zones; and (2) thermosyphon pumping created by natural convection boundary layers. The primary objective of the present study is to compare the characteristics of bulk density driven and boundary layer driven flow, and discuss some of the advantages associated with the use of natural convection boundary layers to transport energy in solar building applications.

  8. antarctic boundary layer: Topics by E-print Network

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

    Geosciences Websites Summary: Boundary Layer Meteorology (METR 5103) Spring 2014 Syllabus General information Fundamentals of the atmospheric boundary layer dynamics and...

  9. atmosperic boundary layer: Topics by E-print Network

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

    Geosciences Websites Summary: Boundary Layer Meteorology (METR 5103) Spring 2014 Syllabus General information Fundamentals of the atmospheric boundary layer dynamics and...

  10. Numerical Simulation of the Wave Bottom Boundary Layer

    E-Print Network [OSTI]

    Slinn, Donald

    boundary layer. Oscillatory boundary layers are examined using a high-resolution time-dependent threeNumerical Simulation of the Wave Bottom Boundary Layer Over a Smooth Surface. Part 1: Three for turbulent boundary layers that occur over a smooth bottom. Results indicate that turbulence levels

  11. Planetary Boundary Layer from AERI and MPL

    SciTech Connect (OSTI)

    Sawyer, Virginia

    2014-02-13T23:59:59.000Z

    The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.

  12. Planetary Boundary Layer from AERI and MPL

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Sawyer, Virginia

    The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.

  13. Turbulent Fluxes in Stably Stratified Boundary Layers

    E-Print Network [OSTI]

    L'vov, Victor S; Rudenko, Oleksii; 10.1088/0031-8949/2008/T132/014010

    2008-01-01T23:59:59.000Z

    We present an extended version of an invited talk given on the International Conference "Turbulent Mixing and Beyond". The dynamical and statistical description of stably stratified turbulent boundary layers with the important example of the stable atmospheric boundary layer in mind is addressed. Traditional approaches to this problem, based on the profiles of mean quantities, velocity second-order correlations, and dimensional estimates of the turbulent thermal flux run into a well known difficulty, predicting the suppression of turbulence at a small critical value of the Richardson number, in contradiction with observations. Phenomenological attempts to overcome this problem suffer from various theoretical inconsistencies. Here we present an approach taking into full account all the second-order statistics, which allows us to respect the conservation of total mechanical energy. The analysis culminates in an analytic solution of the profiles of all mean quantities and all second-order correlations removing t...

  14. arctic boundary layer: Topics by E-print Network

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

    of many theoretical studies over the last forty years. (A Davies, Christopher 18 Tropical cyclone boundary layer shocks CERN Preprints Summary: This paper presents numerical...

  15. atmosphere boundary layer: Topics by E-print Network

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

    Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current...

  16. atmospheric boundary layer: Topics by E-print Network

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

    Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current...

  17. atmospheric boundary layers: Topics by E-print Network

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

    Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current...

  18. Overcoming the Boundary Layer Turbulence at Dome C: Ground-Layer Adaptive Optics versus Tower

    E-Print Network [OSTI]

    Ashley, Michael C. B.

    Overcoming the Boundary Layer Turbulence at Dome C: Ground-Layer Adaptive Optics versus Tower T the boundary layer: mounting a telescope on a tower that physically puts it above the turbulent layer such a goal, two solutions can be proposed. The most intuitive one is to place a telescope on a tower

  19. Analytic Model of the Universal Structure of Turbulent Boundary Layers

    E-Print Network [OSTI]

    Victor S. L'vov; Itamar Procaccia; Oleksii Rudenko

    2006-06-21T23:59:59.000Z

    Turbulent boundary layers exhibit a universal structure which nevertheless is rather complex, being composed of a viscous sub-layer, a buffer zone, and a turbulent log-law region. In this letter we present a simple analytic model of turbulent boundary layers which culminates in explicit formulae for the profiles of the mean velocity, the kinetic energy and the Reynolds stress as a function of the distance from the wall. The resulting profiles are in close quantitative agreement with measurements over the entire structure of the boundary layer, without any need of re-fitting in the different zones.

  20. Interaction between surface and atmosphere in a convective boundary layer /

    E-Print Network [OSTI]

    Garai, Anirban

    2013-01-01T23:59:59.000Z

    of cold fluid constitute most of the heat transport andevent cold air descends to the ground, heat transport fromcold air during sweep events. The convective boundary layer has a great influence on moisture transport,

  1. Distributed boundary layer suction utilizing wing tip effects

    E-Print Network [OSTI]

    Edwards, Jay Thomas

    1962-01-01T23:59:59.000Z

    of this system to existing light aircraft would present no mechanical complications, either in the perforation of the wings or in the maintenance of the system. Recommendations for Other A lications 1. An investigation into the possibility of delaying... Means of Effecting Boundary Layer Control by Suction, " Aeronautical En ineerin Review, September, 1953. 17. Cornish, J. , "Practical High Lift Systems Using Distributed Boundary Layer Control, " Research Report $19, Miss. State College, 1958. 18...

  2. Distributed Roughness Receptivity in a Flat Plate Boundary Layer

    E-Print Network [OSTI]

    Kuester, Matthew Scott

    2014-04-18T23:59:59.000Z

    for the three different unit Reynolds num- ber test conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.4 Spanwise uniformity of boundary layer integral quantities at x = 870 mm for low unit Reynolds number test condition... with the distributed roughness configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.5 Differential pressure across the flat plate leading edge. . . . . . . . . . 25 3.6 Roughness patch (k = 1 mm), before windowing . . . . . . . . . . . . 27 3...

  3. Carbon transport in the bottom boundary layer. Final report

    SciTech Connect (OSTI)

    Agrawal, Y.C.

    1998-10-05T23:59:59.000Z

    This report summarizes the activities and findings from a field experiment devised to estimate the rates and mechanisms of transport of carbon across the continental shelves. The specific site chosen for the experiment was the mid-Atlantic Bight, a region off the North Carolina coast. The experiment involved a large contingent of scientists from many institutions. The specific component of the program was the transport of carbon in the bottom boundary layer. The postulate mechanisms of transport of carbon in the bottom boundary layer are: resuspension and advection, downward deposition, and accumulation. The high turbulence levels in the bottom boundary layer require the understanding of the coupling between turbulence and bottom sediments. The specific issues addressed in the work reported here were: (a) What is the sediment response to forcing by currents and waves? (b) What is the turbulence climate in the bottom boundary layer at this site? and (c) What is the rate at which settling leads to carbon sequestering in bottom sediments at offshore sites?

  4. Polymer Effects on Heat Transport in Laminar Boundary Layer Flow

    E-Print Network [OSTI]

    Roberto Benzi; Emily S. C. Ching; Vivien W. S. Chu

    2011-04-27T23:59:59.000Z

    We consider a laminar Blasius boundary-layer flow above a slightly heated horizontal plate and study the effect of polymer additives on the heat transport. We show that the action of the polymers can be understood as a space-dependent effective viscosity that first increases from the zero-shear value then decreases exponentially back to the zero-shear value as one moves away from the boundary. We find that with such an effective viscosity, both the horizontal and vertical velocities near the plate are decreased thus leading to an increase in the friction drag and a decrease in the heat transport in the flow.

  5. Examining A Hypersonic Turbulent Boundary Layer at Low Reynolds Number

    E-Print Network [OSTI]

    Semper, Michael Thomas

    2013-05-15T23:59:59.000Z

    z spanwise direction, m Greek Symbols boundary layer thickness, m displacement thickness, m ratio of speci c heats hotwire recovery ratio dynamic viscosity, Pa s density, kg=m3 hotwire overheat ratio, Twire=Tt momentum thickness, m... direct numerical simulation LDV laser doppler velocimetry LES large eddy simulation MTV molecular tagging velocimetry OHR overheat ratio (see ) PIV particle image velocimetry PLIF planar laser induced uorescence RANS Reynolds averaged Navier...

  6. Coupled wake boundary layer model of wind-farms

    E-Print Network [OSTI]

    Stevens, Richard J A M; Meneveau, Charles

    2014-01-01T23:59:59.000Z

    We present and test a coupled wake boundary layer (CWBL) model that describes the distribution of the power output in a wind-farm. The model couples the traditional, industry-standard wake expansion/superposition approach with a top-down model for the overall wind-farm boundary layer structure. The wake expansion/superposition model captures the effect of turbine positioning, while the top-down portion adds the interaction between the wind-turbine wakes and the atmospheric boundary layer. Each portion of the model requires specification of a parameter that is not known a-priori. For the wake model the wake expansion coefficient is required, while the top-down model requires an effective span-wise turbine spacing within which the model's momentum balance is relevant. The wake expansion coefficient is obtained by matching the predicted mean velocity at the turbine from both approaches, while the effective span-wise turbine spacing depends on turbine positioning and thus can be determined from the wake expansion...

  7. Improving Subtropical Boundary Layer Cloudiness in the 2011 NCEP GFS

    SciTech Connect (OSTI)

    Fletcher, J. K.; Bretherton, Christopher S.; Xiao, Heng; Sun, Ruiyu N.; Han, J.

    2014-09-23T23:59:59.000Z

    The current operational version of National Centers for Environmental Prediction (NCEP) Global Forecasting System (GFS) shows significant low cloud bias. These biases also appear in the Coupled Forecast System (CFS), which is developed from the GFS. These low cloud biases degrade seasonal and longer climate forecasts, particularly of short-wave cloud radiative forcing, and affect predicted sea surface temperature. Reducing this bias in the GFS will aid the development of future CFS versions and contributes to NCEP's goal of unified weather and climate modelling. Changes are made to the shallow convection and planetary boundary layer parameterisations to make them more consistent with current knowledge of these processes and to reduce the low cloud bias. These changes are tested in a single-column version of GFS and in global simulations with GFS coupled to a dynamical ocean model. In the single-column model, we focus on changing parameters that set the following: the strength of shallow cumulus lateral entrainment, the conversion of updraught liquid water to precipitation and grid-scale condensate, shallow cumulus cloud top, and the effect of shallow convection in stratocumulus environments. Results show that these changes improve the single-column simulations when compared to large eddy simulations, in particular through decreasing the precipitation efficiency of boundary layer clouds. These changes, combined with a few other model improvements, also reduce boundary layer cloud and albedo biases in global coupled simulations.

  8. A case study of boundary layer ventilation by convection and coastal processes

    E-Print Network [OSTI]

    Dacre, Helen

    A case study of boundary layer ventilation by convection and coastal processes H. F. Dacre,1 S. L; published 12 September 2007. [1] It is often assumed that ventilation of the atmospheric boundary layer responsible for ventilation of the atmospheric boundary layer during a nonfrontal day that occurred on 9 May

  9. BOUNDARY LAYER (BL) THERMAL EDDIES OVER A PINE FOREST FROM CARES 2010

    E-Print Network [OSTI]

    BOUNDARY LAYER (BL) THERMAL EDDIES OVER A PINE FOREST FROM CARES 2010 Gunnar Senum and Stephen are three thermal eddies, about 250 meters wide, in the boundary layer. These thermal eddies are formed from the solar heating of the surface and help to form the boundary layer. The eddy updrafts are transporting

  10. Numerical Simulations of the Wave Bottom Boundary Layer over Sand Ripples

    E-Print Network [OSTI]

    Slinn, Donald

    locations. Under conditions of oscillatory potential flow external to the boundary layer causedNumerical Simulations of the Wave Bottom Boundary Layer over Sand Ripples by Thomas Pierro A Thesis boundary layer are believed to play a major role in the re-suspension and transport of sediment, as well

  11. Thermographic analysis of turbulent non-isothermal water boundary layer

    E-Print Network [OSTI]

    Znamenskaya, Irina A

    2015-01-01T23:59:59.000Z

    The paper is devoted to the investigation of the turbulent water boundary layer in the jet mixing flows using high-speed infrared (IR) thermography. Two turbulent mixing processes were studied: a submerged water jet impinging on a flat surface and two intersecting jets in a round disc-shaped vessel. An infrared camera (FLIR Systems SC7700) was focused on the window transparent for IR radiation; it provided high-speed recordings of heat fluxes from a thin water layer close to the window. Temperature versus time curves at different points of water boundary layer near the wall surface were acquired using the IR camera with the recording frequency of 100 Hz. The time of recording varied from 3 till 20 min. The power spectra for the temperature fluctuations at different points on the hot-cold water mixing zone were calculated using the Fast Fourier Transform algorithm. The obtained spectral behavior was compared to the Kolmogorov "-5/3 spectrum" (a direct energy cascade) and the dual-cascade scenario predicted for...

  12. Applications of Fourier analysis in homogenization and boundary layer

    E-Print Network [OSTI]

    Aleksanyan, Hayk; Sjölin, Per

    2012-01-01T23:59:59.000Z

    In this paper we prove convergence results for the boundary layer homogenization problem for solutions of partial differential system with rapidly oscillating Dirichlet data. Our method is based on analysis of oscillatory integrals. In the uniformly convex regime and smooth boundaries we prove pointwise as well as $L^p$ convergence results. Namely, we prove $|u_{\\e}(x)-u_0 (x)| \\leq C_{\\kappa} \\e^{(d-1)/2}\\frac{1}{d(x)^{\\kappa}}$, $\\forall x\\in D$, $ \\forall \\ \\kappa>d-1$, and for $1\\leq pboundary of $D$. In particular for $p=2$ our result relates to the recent result of D. G\\'{e}rarad-Varet and N. Masmoudi \\cite{GM}.

  13. Aerodynamic Models for Hurricanes III. Modeling hurricane boundary layer

    E-Print Network [OSTI]

    Leonov, Arkady I

    2008-01-01T23:59:59.000Z

    The third paper of the series (see previous ones in Refs.[1-2]) discusses basic physicalprocesses in the (quasi-) steady hurricane boundary layer (HBL), develops an approximate airflow model, establishes the HBL structure, and presents integral balance relations for dynamic and thermodynamic variables in HBL. Models of evaporation and condensation are developed, where the condensation is treated similarly to the slow combustion theory. A turbulent approximation for the lower sub-layer of HBL is applied to the sea-air interaction to establish the observed increase in angular momentum in the outer region of HBL.A closed set of balance relations has been obtained. Simple analytical solution of the set yields expressions for the basic dynamic variables - maximal tangential and radial velocities in hurricane, maximal vertical speed in eye wall, the affinity speed of hurricane travel, and the maximal temperature increase after condensation. Estimated values of the variables seem to be realistic. An attempt is also ...

  14. Delaying natural transition of a boundary layer using smooth steps

    E-Print Network [OSTI]

    Xu, Hui; Sherwin, Spencer J

    2015-01-01T23:59:59.000Z

    The boundary layer flow over a smooth forward-facing stepped plate is studied with particular emphasis on the delay of the transition to turbulence. The interaction between the Tollmien-Schlichting (T-S) waves and the base flow over a single/two forward facing smooth steps is conducted by linear analysis indicating the amplitude of the T-S waves are attenuated in the boundary layer over a single smooth plate. Furthermore, we show that two smooth forward facing steps give rise to a further reduction of the amplitude of the T-S waves. A direct numerical simulation (DNS) is performed for the two smooth forward steps correlating favourably with the linear analysis and showing that for the investigated parameters, the K-type transition is inhibited whereas the turbulence onset of the H-type transition is postponed albeit not suppressed. Transition is indeed delayed and drag reduced for both these transition scenarios suggesting smooth forward facing steps could be leveraged as a passive flow control strategy to de...

  15. Laminar-turbulent separatrix in a boundary layer flow

    E-Print Network [OSTI]

    Biau, Damien

    2013-01-01T23:59:59.000Z

    The transitional boundary layer flow over a flat plate is investigated. The boundary layer flow is known to develop unstable Tollmien-Schlichting waves above a critical value of the Reynolds number. However, it is also known that this transition can be observed for sub-critical Reynolds numbers. In that case, the basin of attraction of the laminar state coexists with the sustained turbulence. In this article, the trajectory on the separatrix between these two states is simulated. The state on the separatrix is independent from the initial condition and is dynamically connected to both the laminar flow and the turbulence. Such an edge state provides information regarding the basic features of the transitional flow. The solution takes the form of a low speed streak, flanked by two quasi-streamwise sinuous vortices. The shape of the streaks is close to that simulated with the linear optimal perturbation method. This solution is compared to existing results concerning streak breakdown. The simulations are realize...

  16. Friction of a slider on a granular layer: Nonmonotonic thickness dependence and effect of boundary conditions

    E-Print Network [OSTI]

    Kudrolli, Arshad

    Friction of a slider on a granular layer: Nonmonotonic thickness dependence and effect of boundary the effective friction encountered by a mass sliding on a granular layer as a function of bed thickness and boundary roughness conditions. The observed friction has minima for a small number of layers before

  17. Characterization of Oscillatory Boundary Layer over a Closely Packed Bed of

    E-Print Network [OSTI]

    Apte, Sourabh V.

    Characterization of Oscillatory Boundary Layer over a Closely Packed Bed of Sediment Particles Boundary Layer over a Closely Packed Bed of Sediment Particles Chaitanya D. Ghodke*, Joseph Skitka a detailed knowledge of the small amplitude oscillatory flow over the sediment layer near the sea bed. Fully

  18. METEOROLOGICAL Bulletin of the American Meteorological Society

    E-Print Network [OSTI]

    in the Marine Boundary Layer (CAP-MBL)38 deployment at Graciosa Island in the Azores generated a 21 month (April, distributed, and cited, but please be aware that there will be visual differences and possibly some content to Graciosa Island in the northeastern Atlantic Ocean is providing an unprecedented record of the clouds

  19. Heat transport by laminar boundary layer flow with polymers

    E-Print Network [OSTI]

    Roberto Benzi; Emily S. C. Ching.; Vivien W. S. Chu

    2011-04-23T23:59:59.000Z

    Motivated by recent experimental observations, we consider a steady-state Prandtl-Blasius boundary layer flow with polymers above a slightly heated horizontal plate and study how the heat transport might be affected by the polymers. We discuss how a set of equations can be derived for the problem and how these equations can be solved numerically by an iterative scheme. By carrying out such a scheme, we find that the effect of the polymers is equivalent to producing a space-dependent effective viscosity that first increases from the zero-shear value at the plate then decreases rapidly back to the zero-shear value far from the plate. We further show that such an effective viscosity leads to an enhancement in the drag, which in turn leads to a reduction in heat transport.

  20. Primary, secondary instabilities and control of the rotating-disk boundary layer

    E-Print Network [OSTI]

    ;Typical 3D boundary layers rotating disk swept wing Common features: · crossflow component near the wall · inflection point · strong inviscid instability · secondary instabilities ; growth and saturation of crossflow

  1. Comparison of reflection boundary conditions for langevin equation modeling of convective boundary layer dispersion

    SciTech Connect (OSTI)

    Nasstrom, J.S.; Ermak, D.L.

    1997-04-01T23:59:59.000Z

    Lagrangian stochastic modeling based on the Langevin equation has been shown to be useful for simulating vertical dispersion of trace material in the convective boundary layer or CBL. This modeling approach can account for the effects of the long velocity correlation time scales, skewed vertical velocity distributions, and vertically inhomogeneous turbulent properties found in the CBL. It has been recognized that Langevin equation models assuming skewed but homogenous velocity statistics can capture the important aspects of diffusion from sources in the CBL, especially elevated sources. We compare three reflection boundary conditions using two different Langevin-equation-based numerical models for vertical dispersion in skewed, homogeneous turbulence. One model, described by Ermak and Nasstrom (1995) is based on a Langevin equation with a skewed random force and a linear deterministic force. The second model, used by Hurley and Physick (1993) is based on a Langevin equation with a Gaussian random force and a non-linear deterministic force. The reflection boundary conditions are all based on the approach described by Thompson and Montgomery (1994).

  2. Intercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed during

    E-Print Network [OSTI]

    Zuidema, Paquita

    /crystal concentration also suggests the need for improved understanding of ice nucleation and its parameterizationIntercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed is presented. This case study is based on observations of a persistent mixed-phase boundary layer cloud

  3. INTERANNUAL AND SEASONAL VARIATIONS IN MARINE BOUNDARY LAYER CLOUD FRACTION AND LOWER

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    : ___________________________________________________________ #12;i Abstract Marine boundary layer (MBL) clouds have a large effect on the global radiation budget cooling effect in the MBL. Thus, simulating MBL clouds in General Circulation Models (GCM) is crucialINTERANNUAL AND SEASONAL VARIATIONS IN MARINE BOUNDARY LAYER CLOUD FRACTION AND LOWER TROPOSPHERIC

  4. Bottom boundary layer measurements in OMP. Final report

    SciTech Connect (OSTI)

    Gross, T.F. [Skidaway Inst. of Oceanography, Savannah, GA (United States); Williams, A.J. [Woods Hole Oceanographic Inst., MA (United States)

    1998-11-01T23:59:59.000Z

    The main role of the Benthic Acoustic Stress Sensor (BASS) tripods within the Ocean Margins Program experiments was to detect and quantify organic carbon rich particle transport off the shelf. This requires measures of the turbulent boundary layer flow and bed stress, the physical forcing of the particle transport, as well as the concentration and type of particles which are being transported. The BASS tripods were deployed at sites 17 and 26. Data from site 26 were recovered spanning three periods: Feb. 2--April 6, May 13--June 27, June 28--Aug. 18. Site 17 was occupied Feb. 12--april 11. The BASS tripods were arrayed with five BASS sensors measuring detailed velocity parameters within four meters of the seabed. Velocity time series indicate a usually weak tidal flow which produces small bed stress by itself. On the occasions when a strong flow, probably the Gulf Stream, crosses the area, the bed shear stress increases dramatically to as much as 10 dyne cm{sup {minus}2}. This is competent to move unconsolidated sediments in the area. Other instruments from the tripods include: two conductivity/temperature sensor pairs, five WetStar fluorometers, thermistors, transmissometer, optical backscatterence sensors and a pressure sensor.

  5. EXPERIMENTAL STUDY OF COMBUSTION IN A TURBULENT BOUNDARY LAYER

    E-Print Network [OSTI]

    Cheng, R.K.

    2011-01-01T23:59:59.000Z

    evaporation, but the thermophoretic migration of particlesboundary layer due to thermophoretic motion and evaporation

  6. F/sub 2/ boundary layer measurement in a chemical laser slit nozzle flow

    SciTech Connect (OSTI)

    Spenser, D.J.; Durran, D.A.; Bixler, H.A.; Varwig, R.L.

    1983-02-01T23:59:59.000Z

    A sensitive F2 absorption diagnostic suitable for slit nozzle scanning was developed and applied to the measurement of an F2 boundary layer in an HF chemical laser flow. The F2 boundary layer profile was determined to be of exponential decay form with peak at the nozzle wall and of width approx. 1/3 the viscous boundary layer. The F2 concentration profile was displaced inwardly and slightly compressed by the H2 slit injection at the nozzle exit plane. The F2 profile apparently remains fairly intact in passing through the lasing zone.

  7. Design of a model propulsor for a boundary layer ingesting aircraft

    E-Print Network [OSTI]

    Grasch, Adam D. (Adam Davis)

    2013-01-01T23:59:59.000Z

    This thesis presents contributions to the analysis and design of propulsion simulators for 1:11 and 1:4 scale model wind tunnel investigations of an advanced civil transport aircraft with boundary layer ingestion (BLI). ...

  8. Boundary-Layer Receptivity to Three-Dimensional Roughness Arrays on a Swept-Wing

    E-Print Network [OSTI]

    Hunt, Lauren Elizabeth

    2012-02-14T23:59:59.000Z

    is required. This study uses detailed hotwire boundary-layer velocity scans to quantify the relationship between roughness height and initial disturbance amplitude. Naphthalene flow visualization provides insight into how transition changes as a result...

  9. Advances in the visualization and analysis of boundary layer flow in swimming fish

    E-Print Network [OSTI]

    Anderson, Erik J

    2005-01-01T23:59:59.000Z

    In biology, the importance of fluid drag, diffusion, and heat transfer both internally and externally, suggest the boundary layer as an important subject of investigation, however, the complexities of biological systems ...

  10. Stability Analysis for a Saline Boundary Layer Formed by Uniform Up ow Using Finite Elements

    E-Print Network [OSTI]

    Eindhoven, Technische Universiteit

    density in the deeper underground and high salt water density at the boundary layer), gravitation plays and Darcy's law. In this report we #12;rst give an overview of semi-analytical methods to analyse

  11. The hydrodynamic stability of crossflow vortices in the Bdewadt boundary layer

    E-Print Network [OSTI]

    The hydrodynamic stability of crossflow vortices in the Bödewadt boundary layer N. A. Culverhouse the critical Reynolds number. extends the laminar flow region. decreasing the magnitude of the crossflow

  12. Analysis and interpretation of tidal currents in the coastal boundary layer

    E-Print Network [OSTI]

    May, Paul Wesley, 1950-

    1979-01-01T23:59:59.000Z

    Concern with the impact of human activities on the coastal region of the world's oceans has elicited interest in the so-called "coastal boundary layer"-that band of water adjacent to the coast where ocean currents adjust ...

  13. The aerodynamic characteristics of an airfoil utilizing boundary layer and circulation control

    E-Print Network [OSTI]

    Boothe, Edward Milton

    1965-01-01T23:59:59.000Z

    THE AERODYNAMIC CHARACTERISTICS OF AN AIRFOIL UTILIZING BOUNDARY LAYER AND CIRCULATION CONTROL A Thesis By EDWARD MILTON BOOTHE Submitted to the Graduate College of the Texas ARM University in partial fulfillment of the requirements... . Wind Tunnel IV Auxiliary Equipment EXPERIMENTAL PROCEDURES . 13 Preliminary Tests 13 Measurement of Boundary Layer And Circulation Control Parameters 16 Wind Tunnel Tests of Airfoil Model. 19 Reduction of Experimental Results 20 V RESULTS...

  14. Shipboard measurements of the cloud-capped marine boundary layer during FIRE/ASTEX

    SciTech Connect (OSTI)

    NONE

    1997-09-01T23:59:59.000Z

    Results are reported on measurements of the cloud-capped marine boundary layer during FIRE/ASTEX. A method was developed from the ASTEX dataset for measuring profiles of liquid water content, droplet size and concentration from cloud radar/microwave radiometer data in marine boundary layer clouds. Profiles were also determined from the first three moments of the Doppler spectrum measured in drizzle with the ETL cloud radar during ASTEX.

  15. Design of an Instrumentation System for a Boundary Layer Transition Wing Glove Experiment 

    E-Print Network [OSTI]

    Williams, Thomas 1987-

    2012-08-23T23:59:59.000Z

    of Air * Complex Conjugate CF Crossflow CFD Computational Fluid Dynamics ! Skin Friction Coefficient cgr,n Group Velocity Measured by Sensor-n CN ASHRAE Clearness Factor for Solar Radiation ! Pressure Coefficient !" Specific Heat of Air... Test Engineer Acceleration due to Gravity G-III Gulfstream G-III Business Jet !" Crossflow Similarity Variable for the Falkner-Scan-Cooke Boundary Layer !"! Value of Crossflow Similarity Variable for the Falkner-Scan-Cooke Boundary Layer...

  16. EART 265 Lecture Notes: Boundary Layers We're interested here mainly in boundary layers relevant to planets, i.e. those of planetary atmo-

    E-Print Network [OSTI]

    Nimmo, Francis

    and the surface, thus mediating all interactions between the two. If we look back at the Navier-Stokes equations of a solid (or liquid in the case of gas ows) where diusion is non-negligible. It is characterized by strong then promotes mixing. Outside the boundary layer, uid often mixes only very slowly because turbulence

  17. Technical Tools for Boundary Layers and Applications to Heterogeneous Coefficients

    E-Print Network [OSTI]

    Sarkis, Marcus

    , Poland. This work was supported in part by the Polish Sciences Foundation under grant NN201006933. 2 energy in a thin layer and vice versa, how to control the energy of a discrete harmonic function

  18. Combustion-turbulence interaction in the turbulent boundary layer over a hot surface

    SciTech Connect (OSTI)

    Ng, T.T.; Cheng, R.K.; Robben, F.; Talbot, L.

    1982-01-01T23:59:59.000Z

    The turbulence-combustion interaction in a reacting turbulent boundary layer over a heated flat plate was studied. Ethylene/air mixture with equivalence ratio of 0.35 was used. The free stream velocity was 10.5 m/s and the wall temperature was 1250/sup 0/K. Combustion structures visualization was provided by high-speed schlieren photographs. Fluid density statistics were deduced from Rayleigh scattering intensity measurements. A single-component laser Doppler velocimetry system was used to obtain mean and root-mean-square velocity distributions, the Reynolds stress, the streamwise and the cross-stream turbulent kinetic energy diffusion, and the production of turbulent kinetic energy by Reynolds stress. The combustion process was dominated by large-scale turbulent structures of the boundary layer. Combustion causes expansion of the boundary layer. No overall self-similarity is observed in either the velocity or the density profiles. Velocity fluctuations were increased in part of the boundary layer and the Reynolds stress was reduced. The turbulent kinetic energy diffusion pattern was changed significantly and a modification of the boundary layer assumption will be needed when dealing with this problem analytically. 11 figures, 1 table.

  19. ARM - Field Campaign - Boundary Layer CO2 Using CW Lidar

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032)8Li (59AJ76)ARM2,govCampaignsAircraftCloud ODgovCampaignsBoundary

  20. F/sup 2/ boundary layer measurement in a chemical laser slit nozzle flow. Technical report

    SciTech Connect (OSTI)

    Spencer, D.J.; Durran, D.A.; Bixler, H.A.; Varwig, R.L.

    1983-02-15T23:59:59.000Z

    A sensitive F/sup 2/ absorption diagnostic suitable for slit nozzle scanning was developed and applied to the measurement of an F/sup 2/ boundary layer in an HF chemical laser flow. The F/sup 2/ boundary layer profile was determined to be of exponential decay form with peak at the nozzle wall and of width approx. 1/3 the viscous boundary layer. The F/sup 2/ concentration profile was displaced inwardly and slightly compressed by the H2 slit injection at the nozzle exit plane, which penetration profile followed the relation delta = 0.1(sq. root of x). The F/sup 2/ profile apparently remains fairly intact in passing through the lasing zone.

  1. Lidar Investigation of Tropical Nocturnal Boundary Layer Aerosols and Cloud Macrophysics

    SciTech Connect (OSTI)

    Manoj, M. G.; Devara, PC S.; Taraphdar, Sourav

    2013-10-01T23:59:59.000Z

    Observational evidence of two-way association between nocturnal boundary layer aerosols and cloud macrophysical properties under different meteorological conditions is reported in this paper. The study has been conducted during 2008-09 employing a high space-time resolution polarimetric micro-pulse lidar over a tropical urban station in India. Firstly, the study highlights the crucial role of boundary layer aerosols and background meteorology on the formation and structure of low-level stratiform clouds in the backdrop of different atmospheric stability conditions. Turbulent mixing induced by the wind shear at the station, which is associated with a complex terrain, is found to play a pivotal role in the formation and structural evolution of nocturnal boundary layer clouds. Secondly, it is shown that the trapping of energy in the form of outgoing terrestrial radiation by the overlying low-level clouds can enhance the aerosol mixing height associated with the nocturnal boundary layer. To substantiate this, the long-wave heating associated with cloud capping has been quantitatively estimated in an indirect way by employing an Advanced Research Weather Research and Forecasting (WRF-ARW) model version 2.2 developed by National Center for Atmospheric Research (NCAR), Colorado, USA, and supplementary data sets; and differentiated against other heating mechanisms. The present investigation as well establishes the potential of lidar remote-sensing technique in exploring some of the intriguing aspects of the cloud-environment relationship.

  2. Wind Energy-Related Atmospheric Boundary Layer Large-Eddy Simulation Using OpenFOAM: Preprint

    SciTech Connect (OSTI)

    Churchfield, M.J.; Vijayakumar, G.; Brasseur, J.G.; Moriarty, P.J.

    2010-08-01T23:59:59.000Z

    This paper develops and evaluates the performance of a large-eddy simulation (LES) solver in computing the atmospheric boundary layer (ABL) over flat terrain under a variety of stability conditions, ranging from shear driven (neutral stratification) to moderately convective (unstable stratification).

  3. ESTIMATING BEDROCK AND SURFACE LAYER BOUNDARIES AND CONFIDENCE INTERVALS IN ICE SHEET RADAR IMAGERY USING MCMC

    E-Print Network [OSTI]

    Menczer, Filippo

    ESTIMATING BEDROCK AND SURFACE LAYER BOUNDARIES AND CONFIDENCE INTERVALS IN ICE SHEET RADAR IMAGERY and Computing Indiana University Bloomington, Indiana USA ABSTRACT Climate models that predict polar ice sheet behavior require accurate measurements of the bedrock-ice and ice-air bound- aries in ground

  4. Sensitivity of Swept-Wing, Boundary-Layer Transition to Spanwise-Periodic Discrete Roughness Elements

    E-Print Network [OSTI]

    West, David Edward

    2014-12-12T23:59:59.000Z

    Micron-sized, spanwise-periodic, discrete roughness elements (DREs) were applied to and tested on a 30° swept-wing model in order to study their effects on boundary-layer transition in flight where stationary crossflow waves are the dominant...

  5. Wave-driven wind jets in the marine atmospheric boundary layer

    E-Print Network [OSTI]

    Reading, University of

    Wave-driven wind jets in the marine atmospheric boundary layer Kirsty E. Hanley Stephen E. Belcher;Abstract The interaction between ocean surface waves and the overlying wind leads to a transfer of momentum can also be transferred upwards when long wavelength waves, characteristic of re- motely generated

  6. Behavior of Turbulent Structures within a Mach 5 Mechanically Distorted Boundary Layer

    E-Print Network [OSTI]

    Peltier, Scott Jacob

    2013-08-05T23:59:59.000Z

    field of incompressible boundary layer, taken from Adrian et al. (2000). ............................................................................... 138 Figure 6.15 Schematic of an individual hairpin vortex, describing the sweep and ejection... hairpin vortex, identifying the motions contributing to sweeps and ejections ....................................................................................... 235 Figure 7.46 Illustrations of the possible mechanisms contributing to the reduced...

  7. American Institute of Aeronautics and Astronautics Shock/Boundary Layer Interaction Effects of Transverse

    E-Print Network [OSTI]

    Texas at Arlington, University of

    of Transverse Jets in Crossflow over a Body of Revolution Dean A. Dickmann* Lockheed Martin Missiles and Fire 76019 Shock/boundary layer interaction present in transverse jets in supersonic crossflow alteres suggested a transverse jet in crossflow can be represented by a solid body of given length and shape

  8. Flowfield and wall pressure characteristics downstream of a boundary layer suction device.

    E-Print Network [OSTI]

    Tinney, Charles E.

    Flowfield and wall pressure characteristics downstream of a boundary layer suction device. Meagan A-dimensional slit can significantly reduce the fluctuating wall pressure immediately downstream of the suction slit momentum regions of the flow with the wall at the downstream edge of the suction slit. The third region

  9. Local and Bi-Global Stability Analysis of a Plasma Actuated Boundary Layer

    E-Print Network [OSTI]

    Roy, Subrata

    velocities ¯p Mean pressure ~u, ~v, ~w Disturbance flow velocities ~p Disturbance pressure u , v , w Complex disturbance flow velocities p Complex disturbance pressure u Freestream velocity up Induced velocity Complex spatial frequency in x Complex spatial frequency in z Complex temporal frequency 99% Boundary layer

  10. Elements of comparison between Martian and terrestrial mesoscale meteorological phenomena: Katabatic winds and boundary layer convection

    E-Print Network [OSTI]

    Spiga, Aymeric

    Elements of comparison between Martian and terrestrial mesoscale meteorological phenomena Keywords: Mesoscale meteorology Katabatic winds Boundary layer convection Comparative planetology a b s t r a c t Terrestrial and Martian atmospheres are both characterised by a large variety of mesoscale

  11. Evaluating the Performance of Planetary Boundary Layer and Cloud Microphysical Parameterization Schemes in Convection-Permitting Ensemble Forecasts using

    E-Print Network [OSTI]

    Xue, Ming

    uncertainty in how to include various processes (e.g., drop breakup and ice-phase categories 1 Evaluating the Performance of Planetary Boundary Layer and Cloud Microphysical Parameterization In this study, the ability of several cloud microphysical and planetary boundary layer parameterization schemes

  12. Accumulation mode aerosol, pockets of open cells, and particle nucleation in the remote subtropical Pacific marine boundary layer

    E-Print Network [OSTI]

    Russell, Lynn

    Accumulation mode aerosol, pockets of open cells, and particle nucleation in the remote subtropical in the remote subtropical Pacific marine boundary layer, J. Geophys. Res., 111, D02206, doi:10.1029/2004JD005694 the boundary layer via its action on the budgets of heat and water substance. A plausible consequence may

  13. Resuspension of Small Particles from Multilayer Deposits in Turbulent Boundary Layers

    E-Print Network [OSTI]

    F. Zhang; M. Reeks; M. Kissane; R. J. Perkins

    2012-06-09T23:59:59.000Z

    We present a hybrid stochastic model for the resuspension of micron-size particles from multilayer deposits in a fully-developed turbulent boundary layer. The rate of removal of particles from any given layer depends upon the rate of removal of particles from the layer above which acts as a source of uncovering and exposure of particles to the resuspending flow. The primary resuspension rate constant for an individual particle within a layer is based on the Rock'n'Roll (R'n'R) model using non-Gaussian statistics for the aerodynamic forces acting on the particles (Zhang et al., 2012). The coupled layer equations that describe multilayer resuspension of all the particles in each layer are based on the generic lattice model of Friess & Yadigaroglu (2001) which is extended here to include the influence of layer coverage and particle size distribution. We consider the influence of layer thickness on the resuspension along with the spread of adhesion within layers, and the statistics of non-Gaussian versus Gaussian removal forces including their timescale. Unlike its weak influence on long-term resuspension rates for monolayers, this timescale plays a crucial and influential role in multilayer resuspension. Finally we compare model predictions with those of a large-scale and a mesoscale resuspension test, STORM (Castelo et al., 1999) and BISE (Alloul-Marmor, 2002).

  14. Blockage of natural convection boundary layer flow in a multizone enclosure

    SciTech Connect (OSTI)

    Scott, D.; Anderson, R.; Figliola, R.S.

    1986-02-01T23:59:59.000Z

    This paper reports the results of an experimental study that examines the transition between flow regimes, as a function of aperture size, in a two-zone enclosure with heated and cooled end walls. A constant heat flux boundary condition was maintained on one vertical end wall, and an isothermal cold temperature sink was maintained on the opposite vertical end wall. All of the remaining surfaces were highly insulated. The transition between the boundary layer driven regime and the bulk density driven regime was established as a function of the geometry of the aperture in the partition that separated the hot and cold zones. The results demonstrate that transition from the boundary layer driven regime to the bulk density driven regime is caused by blockage of the boundary layer flow, when the area of the flow aperture is reduced below a critical value. A simple flow model has been developed which predicts that the critical aperture area for the onset of flow blockage is directly proportional to the number of active heat transfer surfaces and inversely proportional to the Rayleigh number which characterizes the level of heating and cooling provided to the active heat transfer surfaces.

  15. Quasi-periodic oscillations as global hydrodynamic modes in the boundary layers of viscous accretion disks

    E-Print Network [OSTI]

    M. Hakan Erkut; Dimitrios Psaltis; M. Ali Alpar

    2008-07-28T23:59:59.000Z

    The observational characteristics of quasi-periodic oscillations (QPOs) from accreting neutron stars strongly indicate the oscillatory modes in the innermost regions of accretion disks as a likely source of the QPOs. The inner regions of accretion disks around neutron stars can harbor very high frequency modes related to the radial epicyclic frequency $\\kappa $. The degeneracy of $\\kappa $ with the orbital frequency $\\Omega $ is removed in a non-Keplerian boundary or transition zone near the magnetopause between the disk and the compact object. We show, by analyzing the global hydrodynamic modes of long wavelength in the boundary layers of viscous accretion disks, that the fastest growing mode frequencies are associated with frequency bands around $\\kappa $ and $\\kappa \\pm \\Omega $. The maximum growth rates are achieved near the radius where the orbital frequency $\\Omega $ is maximum. The global hydrodynamic parameters such as the surface density profile and the radial drift velocity determine which modes of free oscillations will grow at a given particular radius in the boundary layer. In accordance with the peak separation between kHz QPOs observed in neutron-star sources, the difference frequency between two consecutive bands of the fastest growing modes is always related to the spin frequency of the neutron star. This is a natural outcome of the boundary condition imposed by the rotating magnetosphere on the boundary region of the inner disk.

  16. Experimental investigation of sound generation by a protuberance in a laminar boundary layer

    SciTech Connect (OSTI)

    Kobayashi, M.; Asai, M.; Inasawa, A. [Department of Aerospace Engineering, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, Tokyo 191-0065 (Japan)

    2014-08-15T23:59:59.000Z

    Sound radiation from a two-dimensional protuberance glued on the wall in a laminar boundary layer was investigated experimentally at low Mach numbers. When the protuberance was as high as the boundary-layer thickness, a feedback-loop mechanism set in between protuberance-generated sound and Tollmien-Schlichting (T-S) waves generated by the leading-edge receptivity to the upstream-propagating sound. Although occurrence of a separation bubble immediately upstream of the protuberance played important roles in the evolution of instability waves into vortices interacting with the protuberance, the frequency of tonal vortex sound was determined by the selective amplification of T-S waves in the linear instability stage upstream of the separation bubble and was not affected by the instability of the separation bubble.

  17. Viscous boundary layers of radiation-dominated, relativistic jets. II. The free-streaming jet model

    E-Print Network [OSTI]

    Coughlin, Eric R

    2015-01-01T23:59:59.000Z

    We analyze the interaction of a radiation-dominated jet and its surroundings using the equations of radiation hydrodynamics in the viscous limit. In a previous paper we considered the two-stream scenario, which treats the jet and its surroundings as distinct media interacting through radiation viscous forces. Here we present an alternative boundary layer model, known as the free-streaming jet model -- where a narrow stream of fluid is injected into a static medium -- and present solutions where the flow is ultrarelativistic and the boundary layer is dominated by radiation. It is shown that these jets entrain material from their surroundings and that their cores have a lower density of scatterers and a harder spectrum of photons, leading to observational consequences for lines of sight that look "down the barrel of the jet." These jetted outflow models may be applicable to the jets produced during long gamma-ray bursts and super-Eddington phases of tidal disruption events.

  18. Viscous boundary layers of radiation-dominated, relativistic jets. I. The two-stream model

    E-Print Network [OSTI]

    Coughlin, Eric R

    2015-01-01T23:59:59.000Z

    Using the relativistic equations of radiation hydrodynamics in the viscous limit, we analyze the boundary layers that develop between radiation-dominated jets and their environments. In this paper we present the solution for the self-similar, 2-D, plane-parallel two-stream problem, wherein the jet and the ambient medium are considered to be separate, interacting fluids, and we compare our results to those of previous authors. (In a companion paper we investigate an alternative scenario, known as the free-streaming jet model.) Consistent with past findings, we show that the boundary layer that develops between the jet and its surroundings creates a region of low-density material. These models may be applicable to sources such as super-Eddington tidal disruption events and long gamma-ray bursts.

  19. Sangamon field experiments: observations of the diurnal evolution of the planetary boundary layer over land

    SciTech Connect (OSTI)

    Hicks, B.B.; Hess, G.D.; Wesely, M.L.; Yamada, T.; Frenzen, P.; Hart, R.L.; Sisterson, D.L.; Hess, P.E.; Kulhanek, F.C.; Lipschutz, R.C.; Zerbe, G.A.

    1981-09-01T23:59:59.000Z

    Two complementary experimental studies of the evolving structure of the lower 2 km of the atmosphere, conducted over farmlands in central Illinois during essentially the same mid-summer weeks of two successive years, are described. The first experiment (21 July - 13 August 1975) investigated the early morning break up of the nocturnal stable layer and the rapid growth of the mixed layer before noon; the second (16 to 30 July 1976) examined the decline of the mixed layer through the late afternoon and evening, and the formation and intensification of the ground-based inversion before midnight. Methods of observation and data reduction are summarized in some detail, and the data obtained in the form of hourly wind and temperature profiles, plus sufficient surface flux information to characterize the lower boundary conditions, are tabulated in a series of appendices. These results constitute complete data sets which may be used to test models of the diurnal evolution of the lower atmosphere.

  20. Long-term Observations of the Convective Boundary Layer Using Insect Radar Returns at the SGP ARM Climate Research Facility

    SciTech Connect (OSTI)

    Chandra, A S; Kollias, P; Giangrande, S E; Klein, S A

    2009-08-20T23:59:59.000Z

    A long-term study of the turbulent structure of the convective boundary layer (CBL) at the U.S. Department of Energy Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP) Climate Research Facility is presented. Doppler velocity measurements from insects occupying the lowest 2 km of the boundary layer during summer months are used to map the vertical velocity component in the CBL. The observations cover four summer periods (2004-08) and are classified into cloudy and clear boundary layer conditions. Profiles of vertical velocity variance, skewness, and mass flux are estimated to study the daytime evolution of the convective boundary layer during these conditions. A conditional sampling method is applied to the original Doppler velocity dataset to extract coherent vertical velocity structures and to examine plume dimension and contribution to the turbulent transport. Overall, the derived turbulent statistics are consistent with previous aircraft and lidar observations. The observations provide unique insight into the daytime evolution of the convective boundary layer and the role of increased cloudiness in the turbulent budget of the subcloud layer. Coherent structures (plumes-thermals) are found to be responsible for more than 80% of the total turbulent transport resolved by the cloud radar system. The extended dataset is suitable for evaluating boundary layer parameterizations and testing large-eddy simulations (LESs) for a variety of surface and cloud conditions.

  1. Variability of ozone in the marine boundary layer of the equatorial Pacific Ocean1 Xiao-Ming Hu1

    E-Print Network [OSTI]

    Thompson, Anne

    marine boundary layer of the Kwajalein Atoll, Republic of the Marshall Islands (latitude 8o 43'3 N al., 2000; Horowitz et al., 2003; Yang et13 al., 2005; von Glasow, 2008). Due to logistical

  2. An empirical model for the mean-velocity profiles of a turbulent boundary layer under the effects of surface curvature 

    E-Print Network [OSTI]

    Huynh, Long Quang

    1994-01-01T23:59:59.000Z

    An empirical model has been developed to predict the mean-velocity profile of a turbulent boundary layer under the influence of surface curvature. The model proposed is able to determine the profiles for both a convex and concave curvature...

  3. An empirical model for the mean-velocity profiles of a turbulent boundary layer under the effects of surface curvature

    E-Print Network [OSTI]

    Huynh, Long Quang

    1994-01-01T23:59:59.000Z

    An empirical model has been developed to predict the mean-velocity profile of a turbulent boundary layer under the influence of surface curvature. The model proposed is able to determine the profiles for both a convex and concave curvature...

  4. Prediction of continental shelf sediment transport using a theoretical model of the wave-current boundary layer

    E-Print Network [OSTI]

    Goud, Margaret R

    1987-01-01T23:59:59.000Z

    This thesis presents an application of the Grant-Madsen-Glenn bottom boundary layer model (Grant and Madsen, 1979; Glenn and Grant, 1987) to predictions of sediment transport on the continental shelf. The analysis is a ...

  5. Conditionally-Sampled Turbulent and Nonturbulent Measurements of Entropy Generation Rate in the Transition Region of Boundary Layers

    SciTech Connect (OSTI)

    D. M. McEligot; J. R. Wolf; K. P. Nolan; E. J. Walsh; R. J. Volino

    2006-05-01T23:59:59.000Z

    Conditionally-sampled boundary layer data for an accelerating transitional boundary layer have been analyzed to calculate the entropy generation rate in the transition region. By weighing the nondimensional dissipation coefficient for the laminar-conditioned-data and turbulent-conditioned-data with the intermittency factor the average entropy generation rate in the transition region can be determined and hence be compared to the time averaged data and correlations for steady laminar and turbulent flows. It is demonstrated that this method provides, for the first time, an accurate and detailed picture of the entropy generation rate during transition. The data used in this paper have been taken from detailed boundary layer measurements available in the literature. This paper provides, using an intermittency weighted approach, a methodology for predicting entropy generation in a transitional boundary layer.

  6. Accretion Disk Boundary Layers Around Neutron Stars: X-ray Production in Low-Mass X-ray Binaries

    E-Print Network [OSTI]

    Robert Popham; Rashid Sunyaev

    2000-04-03T23:59:59.000Z

    We present solutions for the structure of the boundary layer where the accretion disk meets the neutron star, which is expected to be the dominant source of high-energy radiation in low-mass X-ray binaries which contain weakly magnetized accreting neutron stars. We find that the main portion of the boundary layer gas is hot (> ~10^8 K), low in density, radially and vertically extended, and optically thick to scattering but optically thin to absorption. It will produce large X-ray luminosity by Comptonization. Energy is transported inward by viscosity, concentrating the energy dissipation in the dense, optically thick zone close to the stellar surface. We explore the dependence of the boundary layer structure on the mass accretion rate, the rotation rate of the star, the alpha viscosity parameter and the viscosity prescription. Radiation pressure is the dominant source of pressure in the boundary layer; the flux is close to the Eddington limiting flux even for luminosities well below (~0.01 times) L(Edd). At luminosities near L(Edd), the boundary layer expands radially, and has a radial extent larger than one stellar radius. Based on the temperatures and optical depths which characterize the boundary layer, we expect that Comptonization will produce a power-law spectrum at low source luminosities. At high luminosities, a Planckian spectrum will be produced in the dense region where most of the energy is released, and modified by Comptonization as the radiation propagates outward.

  7. An enriched finite element model with q-refinement for radiative boundary layers in glass cooling

    SciTech Connect (OSTI)

    Mohamed, M. Shadi [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)] [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Seaid, Mohammed; Trevelyan, Jon [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom)] [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Laghrouche, Omar [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)] [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)

    2014-02-01T23:59:59.000Z

    Radiative cooling in glass manufacturing is simulated using the partition of unity finite element method. The governing equations consist of a semi-linear transient heat equation for the temperature field and a stationary simplified P{sub 1} approximation for the radiation in non-grey semitransparent media. To integrate the coupled equations in time we consider a linearly implicit scheme in the finite element framework. A class of hyperbolic enrichment functions is proposed to resolve boundary layers near the enclosure walls. Using an industrial electromagnetic spectrum, the proposed method shows an immense reduction in the number of degrees of freedom required to achieve a certain accuracy compared to the conventional h-version finite element method. Furthermore the method shows a stable behaviour in treating the boundary layers which is shown by studying the solution close to the domain boundaries. The time integration choice is essential to implement a q-refinement procedure introduced in the current study. The enrichment is refined with respect to the steepness of the solution gradient near the domain boundary in the first few time steps and is shown to lead to a further significant reduction on top of what is already achieved with the enrichment. The performance of the proposed method is analysed for glass annealing in two enclosures where the simplified P{sub 1} approximation solution with the partition of unity method, the conventional finite element method and the finite difference method are compared to each other and to the full radiative heat transfer as well as the canonical Rosseland model.

  8. Numerical modeling of boundary layer flow under shoaling and breaking waves

    E-Print Network [OSTI]

    Pattipawaej, Olga Catherina

    1998-01-01T23:59:59.000Z

    is governed by the mass conservation equation 0U 0W ? + =0 0x 0" (2. 1) and the boundary layer approximation to the horizontal momentum equation DU 0U?0U 0 I 0U +U ?+ ? iv ? ?&utc& (2. 2) where D 0 0 0 ? = ? + U ? + W ?. Dt 0t 0z 0 (2. 3) In 2. 1 and 2... stresses. Following Kanetkar (1985), the governing equations 2. 11 and 2. 12 can be written to the first order of approximation as (3. 1) = cqql ? + ? cscsql ? ? ? ci? (3. 2) where the value of ci is found to be 0. 054 by setting production equal...

  9. The effect of tangential mass addition on the boundary layer velocity distribution of a flat plate at zero angle of attack

    E-Print Network [OSTI]

    Miller, Edward Peter

    1965-01-01T23:59:59.000Z

    . V . RESULTS AND DISCUSSION 16 18 20 21 24 Boundary Layer Conditions Downstream of Blowing Slot . Boundary Layer Conditions Upstream of Slot Accuracy of Data 24 40 47 VI. CONCLUSIONS AND RECOMMENDATIONS ~ 51 LITERATURE CITED 54 APPENDIX... of u with Distance Downstream of Slot max Velocity Profile of a Boundary Layer in the Presence of a Blowing Jet 32 7 ~ Comparison of Boundaries A, 8, C, in, Present Experiment with that of Carriere and Eichelbrenner's Results 37 Comparison...

  10. icBIE: A Boundary Integral Equation Program for an Ion Channel in Layered Membrane/Electrolyte Media

    E-Print Network [OSTI]

    Cai, Wei

    in this paper. The program uses a layered media Green's function of the P-B equation in order to accurately and Electromagnetics. External routines/libraries: OpenMP (http://openmp.org/wp/) Nature of problem: Electrostatic method: Boundary integral equation method and the layered media Green's function of the Poisson

  11. X-ray and EUV Spectroscopy of the Boundary Layer Emission of Nonmagnetic Cataclysmic Variables

    E-Print Network [OSTI]

    Christopher W. Mauche

    1997-09-11T23:59:59.000Z

    EUVE, ROSAT, and ASCA observations of the boundary layer emission of nonmagnetic cataclysmic variables (CVs) are reviewed. EUVE spectra reveal that the effective temperature of the soft component of high-Mdot nonmagnetic CVs is kT ~ 10-20 eV and that its luminosity is ~ 0.1-0.5 times the accretion disk luminosity. Although the EUV spectra are very complex and belie simple interpretation, the physical conditions of the boundary layer gas are constrained by emission lines of highly ionized Ne, Mg, Si, and Fe. ROSAT and ASCA spectra of the hard component of nonmagnetic CVs are satisfactorily but only phenomenologically described by multi-temperature thermal plasmas, and the constraints imposed on the physical conditions of this gas are limited by the relatively weak and blended lines. It is argued that significant progress in our understanding of the X-ray spectra of nonmagnetic CVs will come with future observations with XMM, AXAF, and Astro-E.

  12. THE SIMULATION OF FINE SCALE NOCTURNAL BOUNDARY LAYER MOTIONS WITH A MESO-SCALE ATMOSPHERIC MODEL

    SciTech Connect (OSTI)

    Werth, D.; Kurzeja, R.; Parker, M.

    2009-04-02T23:59:59.000Z

    A field project over the Atmospheric Radiation Measurement-Clouds and Radiation Testbed (ARM-CART) site during a period of several nights in September, 2007 was conducted to explore the evolution of the low-level jet (LLJ). Data was collected from a tower and a sodar and analyzed for turbulent behavior. To study the full range of nocturnal boundary layer (NBL) behavior, the Regional Atmospheric Modeling System (RAMS) was used to simulate the ARM-CART NBL field experiment and validated against the data collected from the site. This model was run at high resolution, and is ideal for calculating the interactions among the various motions within the boundary layer and their influence on the surface. The model reproduces adequately the synoptic situation and the formation and dissolution cycles of the low-level jet, although it suffers from insufficient cloud production and excessive nocturnal cooling. The authors suggest that observed heat flux data may further improve the realism of the simulations both in the cloud formation and in the jet characteristics. In a higher resolution simulation, the NBL experiences motion on a range of timescales as revealed by a wavelet analysis, and these are affected by the presence of the LLJ. The model can therefore be used to provide information on activity throughout the depth of the NBL.

  13. Immersed Boundary Methods for High-Resolution Simulation of Atmospheric Boundary-Layer Flow Over Complex Terrain

    E-Print Network [OSTI]

    Lundquist, Katherine Ann

    2010-01-01T23:59:59.000Z

    large-eddy simulations within mesoscale simulations for windEddy Simulation of a Mesoscale Convective Internal Boundary185, 1957. Pielke, R. , Mesoscale Meteorological Modeling,

  14. Turbulent flow over a house in a simulated hurricane boundary layer

    E-Print Network [OSTI]

    Taylor, Zachary; Gurka, Roi; Kopp, Gregory

    2009-01-01T23:59:59.000Z

    Every year hurricanes and other extreme wind storms cause billions of dollars in damage worldwide. For residential construction, such failures are usually associated with roofs, which see the largest aerodynamic loading. However, determining aerodynamic loads on different portions of North American houses is complicated by the lack of clear load paths and non-linear load sharing in wood frame roofs. This problem of fluid-structure interaction requires both wind tunnel testing and full-scale structural testing. A series of wind tunnel tests have been performed on a house in a simulated atmospheric boundary layer (ABL), with the resulting wind-induced pressures applied to the full-scale structure. The ABL was simulated for flow over open country terrain where both velocity and turbulence intensity profiles, as well as spectra, were matched with available full scale measurements for this type of terrain. The first set of measurements was 600 simultaneous surface pressure measurements over the entire house. A key...

  15. Photophoretic contribution to the transport of absorbing particles across combustion gas boundary layers

    SciTech Connect (OSTI)

    Castillo, J.L. (U.N.E.D., Madrid (Spain)); Mackowski, D.W.; Rosner, D.E. (Yale Univ., New Haven, CT (USA))

    1989-01-01T23:59:59.000Z

    Since radiation energy fluxes can be comparable to convective (Fourier) fluxes in large fossil-fuel-fired power stations and furnaces, the authors have examined particle drift (phoresis) induced by nonuniform photon-particle heating in a host gas. The authors analysis of the photophoretic velocity includes the important slipflow regime, and the numerical results show that photophoresis is a significant transport mechanism for micron-sized absorbing particles in high radiative transfer combustion environments, with equivalent photophoretic diffusivities (dimensionless photophoretic velocities) being as large as 10% of the better-known thermophoretic diffusivity (Rosner, 1980, 1985). Since previous experimental results (Rosner and Kim, 1984) demonstrated that thermophoresis causes over a 3-decade increase in particle deposition rates by convective diffusion, clearly, for small, absorbing particles, photophoresis will also be an important contributor to observed deposition rates. Accordingly, they present mass transfer coefficients for particle transport across laminar gaseous boundary layers, including both particle thermophoresis and photophoresis.

  16. Electron distributions observed with Langmuir waves in the plasma sheet boundary layer

    SciTech Connect (OSTI)

    Hwang, Junga [Solar and Space Weather Research Group, Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Department of Astronomy and Space Science, University of Science and Technology, Daejeon (Korea, Republic of); Rha, Kicheol [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Seough, Jungjoon [Solar and Space Weather Research Group, Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Yoon, Peter H. [School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States)

    2014-09-15T23:59:59.000Z

    The present paper investigates the Langmuir turbulence driven by counter-streaming electron beams and its plausible association with observed features in the Earth's plasma sheet boundary layer region. A one-dimensional electrostatic particle-in-cell simulation code is employed in order to simulate broadband electrostatic waves with characteristic frequency in the vicinity of the electron plasma frequency ?/?{sub pe}?1.0. The present simulation confirms that the broadband electrostatic waves may indeed be generated by the counter-streaming electron beams. It is also found that the observed feature associated with low energy electrons, namely quasi-symmetric velocity space plateaus, are replicated according to the present simulation. However, the present investigation only partially succeeds in generating the suprathermal tails such that the origin of observed quasi power-law energetic population formation remains outstanding.

  17. Pulsed Plasma with Synchronous Boundary Voltage for Rapid Atomic Layer Etching

    SciTech Connect (OSTI)

    Economou, Demetre J.; Donnelly, Vincent M.

    2014-05-13T23:59:59.000Z

    Atomic Layer ETching (ALET) of a solid with monolayer precision is a critical requirement for advancing nanoscience and nanotechnology. Current plasma etching techniques do not have the level of control or damage-free nature that is needed for patterning delicate sub-20 nm structures. In addition, conventional ALET, based on pulsed gases with long reactant adsorption and purging steps, is very slow. In this work, novel pulsed plasma methods with synchronous substrate and/or “boundary electrode” bias were developed for highly selective, rapid ALET. Pulsed plasma and tailored bias voltage waveforms provided controlled ion energy and narrow energy spread, which are critical for highly selective and damage-free etching. The broad goal of the project was to investigate the plasma science and engineering that will lead to rapid ALET with monolayer precision. A combined experimental-simulation study was employed to achieve this goal.

  18. Coupled Mesoscale-Large-Eddy Modeling of Realistic Stable Boundary Layer Turbulence

    E-Print Network [OSTI]

    Wang, Yao; Manuel, Lance

    2013-01-01T23:59:59.000Z

    Site-specific flow and turbulence information are needed for various practical applications, ranging from aerodynamic/aeroelastic modeling for wind turbine design to optical diffraction calculations. Even though highly desirable, collecting on-site meteorological measurements can be an expensive, time-consuming, and sometimes a challenging task. In this work, we propose a coupled mesoscale-large-eddy modeling framework to synthetically generate site-specific flow and turbulence data. The workhorses behind our framework are a state-of-the-art, open-source atmospheric model called the Weather Research and Forecasting (WRF) model and a tuning-free large-eddy simulation (LES) model. Using this coupled framework, we simulate a nighttime stable boundary layer (SBL) case from the well-known CASES-99 field campaign. One of the unique aspects of this work is the usage of a diverse range of observations for characterization and validation. The coupled models reproduce certain characteristics of observed low-level jets....

  19. 'Maximum' entropy production in self-organized plasma boundary layer: A thermodynamic discussion about turbulent heat transport

    SciTech Connect (OSTI)

    Yoshida, Z. [Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8561 (Japan); Mahajan, S. M. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

    2008-03-15T23:59:59.000Z

    A thermodynamic model of a plasma boundary layer, characterized by enhanced temperature contrasts and ''maximum entropy production,'' is proposed. The system shows bifurcation if the heat flux entering through the inner boundary exceeds a critical value. The state with a larger temperature contrast (larger entropy production) sustains a self-organized flow. An inverse cascade of energy is proposed as the underlying physical mechanism for the realization of such a heat engine.

  20. A study of low-level wind and temperature profiles as a function of stability in the surface boundary layer

    E-Print Network [OSTI]

    Williams, Morgan Glenn

    1970-01-01T23:59:59.000Z

    A STUDY OF LOW-LEVEL WIND AND TEMPERATURE PROFILES AS A FUNCTION OF STABILITY IN THE SURFACE BOUNDARY LAYER A Thesis By Morgan Glenn Williams Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... and content by: . . jy ~( (Chairman of Committee) (lread of Dep. ent) ', ea'ocr) ~!A|I)~ Decemb. r 19 70 ABSTRACT A Study of I. ow-Level Wind and Temperature Profiles as a Function of Stability in the Surface Boundary Layer (December 1970) Morgan...

  1. Wind profile above the surface boundary layer S.-E. Gryning (1), E. Batchvarova (2) and B. Brmmer (3)

    E-Print Network [OSTI]

    Wind profile above the surface boundary layer S.-E. Gryning (1), E. Batchvarova (2) and B. Brümmer in predictions of the wind profile in the lowest hundreds me- ters of the atmosphere, being connected to the general increase in height of structures such as bridges, high houses and wind turbines. The hub height

  2. Evolution and lifetimes of flow topology in a turbulent boundary layer G. E. Elsinga and I. Marusic

    E-Print Network [OSTI]

    Marusic, Ivan

    -similar forms of fluid flow and heat-mass transfer in turbulent boundary layer flow of a nanofluid Phys. Fluids that are coherent in time and space, commonly referred to as eddies or coherent structures.1 They are fundamental remain regarding the dynamics and time scales of these coherent motions. In this study we provide a first

  3. Boundary-Layer Meteorol (2009) 132:129149 DOI 10.1007/s10546-009-9380-8

    E-Print Network [OSTI]

    Porté-Agel, Fernando

    2009-01-01T23:59:59.000Z

    deficit and the turbulence intensity, which are important factors affecting turbine power generation by Vermeer et al. (2003). Detailed understanding of the turbulent properties of turbine wakes under different-Tunnel Investigation of Wind-Turbine Wakes: Boundary-Layer Turbulence Effects Leonardo P. Chamorro · Fernando Porté

  4. DOI 10.1007/s10546-005-9005-9 Boundary-Layer Meteorology (2006) 119: 135157 Springer 2006

    E-Print Network [OSTI]

    and to the thermal internal boundary-layer formation. The strong coastal and orographic influences sensing systems such as lidars use aerosols as tracers, with the optical power measured by a lidar proportional to the aerosol content of the atmosphere. The lidar signal shows strong backscattering within

  5. DOI 10.1007/s10546-005-7772-y Boundary-Layer Meteorology (2006) 118: 477501 Springer 2006

    E-Print Network [OSTI]

    Ribes, Aurélien

    2006-01-01T23:59:59.000Z

    radial velocity measurements on a 6-km radius area in the lowest 3 km of the troposphere. Thus the urban effects appear to be negligible. Keywords: Atmospheric boundary layer, Doppler lidar, Numerical the Marseille area are compared to the Doppler lidar data, for which the spatial res- olution is comparable

  6. Nature of the Mesoscale Boundary Layer Height and Water Vapor Variability Observed 14 June 2002 during the IHOP_2002 Campaign

    E-Print Network [OSTI]

    Guichard, Francoise

    Nature of the Mesoscale Boundary Layer Height and Water Vapor Variability Observed 14 June 2002, Boulder, Colorado (Manuscript received 4 September 2007, in final form 23 June 2008) ABSTRACT Mesoscale at the mesoscale, with the spatial pattern and the magnitude of the variability changing from day to day. On 14

  7. Two-equation model computations of high-speed (ma=2.25, 7.2), turbulent boundary layers

    E-Print Network [OSTI]

    Arasanipalai, Sriram Sharan

    2009-05-15T23:59:59.000Z

    of the Boussinesq coefficient (Cu) and turbulenttransport coefficients (sigmak; sigmaE; sigma; sigma*) on the boundary layer ow is examined. Further,the performance of a new model with realizability-based correction to Cu and corresponding modifications to sigma...

  8. Boundary-Layer Meteorol (2010) 134:157180 DOI 10.1007/s10546-009-9433-z

    E-Print Network [OSTI]

    Gentine, Pierre

    2010-01-01T23:59:59.000Z

    forcing is dependent on the heat storage and diffusion as well as on the coupling of the soil of surface state variables to the frequency of the forcing is analyzed. Keywords Diurnal cycle · Ground heat cycle of temperature and heat-flux profiles in a coupled land- surface and atmospheric boundary layer

  9. Boundary Layer Convergence Induced by Strong Winds across a Midlatitude THOMAS KILPATRICK, NIKLAS SCHNEIDER, AND BO QIU

    E-Print Network [OSTI]

    Qiu, Bo

    Boundary Layer Convergence Induced by Strong Winds across a Midlatitude SST Front* THOMAS in an idealized, dry, two- dimensional configuration, for winds crossing from cold to warm SST and from warm to cold SST. For strong cross-front winds, O(10 m s21 ), changes in the turbulent mixing and MABL depth

  10. Transforming the representation of the boundary layer and low clouds for high-resolution regional climate modeling: Final report

    SciTech Connect (OSTI)

    Huang, Hsin-Yuan; Hall, Alex

    2013-07-24T23:59:59.000Z

    Stratocumulus and shallow cumulus clouds in subtropical oceanic regions (e.g., Southeast Pacific) cover thousands of square kilometers and play a key role in regulating global climate (e.g., Klein and Hartmann, 1993). Numerical modeling is an essential tool to study these clouds in regional and global systems, but the current generation of climate and weather models has difficulties in representing them in a realistic way (e.g., Siebesma et al., 2004; Stevens et al., 2007; Teixeira et al., 2011). While numerical models resolve the large-scale flow, subgrid-scale parameterizations are needed to estimate small-scale properties (e.g. boundary layer turbulence and convection, clouds, radiation), which have significant influence on the resolved scale due to the complex nonlinear nature of the atmosphere. To represent the contribution of these fine-scale processes to the resolved scale, climate models use various parameterizations, which are the main pieces in the model that contribute to the low clouds dynamics and therefore are the major sources of errors or approximations in their representation. In this project, we aim to 1) improve our understanding of the physical processes in thermal circulation and cloud formation, 2) examine the performance and sensitivity of various parameterizations in the regional weather model (Weather Research and Forecasting model; WRF), and 3) develop, implement, and evaluate the advanced boundary layer parameterization in the regional model to better represent stratocumulus, shallow cumulus, and their transition. Thus, this project includes three major corresponding studies. We find that the mean diurnal cycle is sensitive to model domain in ways that reveal the existence of different contributions originating from the Southeast Pacific land-masses. The experiments suggest that diurnal variations in circulations and thermal structures over this region are influenced by convection over the Peruvian sector of the Andes cordillera, while the mostly dry mountain-breeze circulations force an additional component that results in semi-diurnal variations near the coast. A series of numerical tests, however, reveal sensitivity of the simulations to the choice of vertical grid, limiting the possibility of solid quantitative statements on the amplitudes and phases of the diurnal and semidiurnal components across the domain. According to our experiments, the Mellor-Yamada-Nakanishi-Niino (MYNN) boundary layer scheme and the WSM6 microphysics scheme is the combination of schemes that performs best. For that combination, mean cloud cover, liquid water path, and cloud depth are fairly wellsimulated, while mean cloud top height remains too low in comparison to observations. Both microphysics and boundary layer schemes contribute to the spread in liquid water path and cloud depth, although the microphysics contribution is slightly more prominent. Boundary layer schemes are the primary contributors to cloud top height, degree of adiabaticity, and cloud cover. Cloud top height is closely related to surface fluxes and boundary layer structure. Thus, our study infers that an appropriate tuning of cloud top height would likely improve the low-cloud representation in the model. Finally, we show that entrainment governs the degree of adiabaticity, while boundary layer decoupling is a control on cloud cover. In the intercomparison study using WRF single-column model experiments, most parameterizations show a poor agreement of the vertical boundary layer structure when compared with large-eddy simulation models. We also implement a new Total-Energy/Mass- Flux boundary layer scheme into the WRF model and evaluate its ability to simulate both stratocumulus and shallow cumulus clouds. Result comparisons against large-eddy simulation show that this advanced parameterization based on the new Eddy-Diffusivity/Mass-Flux approach provides a better performance than other boundary layer parameterizations.

  11. On the Interaction between Marine Boundary Layer Cellular Cloudiness and Surface Heat Fluxes

    SciTech Connect (OSTI)

    Kazil, J.; Feingold, G.; Wang, Hailong; Yamaguchi, T.

    2014-01-02T23:59:59.000Z

    The interaction between marine boundary layer cellular cloudiness and surface uxes of sensible and latent heat is investigated. The investigation focuses on the non-precipitating closed-cell state and the precipitating open-cell state at low geostrophic wind speed. The Advanced Research WRF model is used to conduct cloud-system-resolving simulations with interactive surface fluxes of sensible heat, latent heat, and of sea salt aerosol, and with a detailed representation of the interaction between aerosol particles and clouds. The mechanisms responsible for the temporal evolution and spatial distribution of the surface heat fluxes in the closed- and open-cell state are investigated and explained. It is found that the horizontal spatial structure of the closed-cell state determines, by entrainment of dry free tropospheric air, the spatial distribution of surface air temperature and water vapor, and, to a lesser degree, of the surface sensible and latent heat flux. The synchronized dynamics of the the open-cell state drives oscillations in surface air temperature, water vapor, and in the surface fluxes of sensible and latent heat, and of sea salt aerosol. Open-cell cloud formation, cloud optical depth and liquid water path, and cloud and rain water path are identified as good predictors of the spatial distribution of surface air temperature and sensible heat flux, but not of surface water vapor and latent heat flux. It is shown that by enhancing the surface sensible heat flux, the open-cell state creates conditions by which it is maintained. While the open-cell state under consideration is not depleted in aerosol, and is insensitive to variations in sea-salt fluxes, it also enhances the sea-salt flux relative to the closed-cell state. In aerosol-depleted conditions, this enhancement may replenish the aerosol needed for cloud formation, and hence contribute to the perpetuation of the open-cell state as well. Spatial homogenization of the surface fluxes is found to have only a small effect on cloud properties in the investigated cases. This indicates that sub-grid scale spatial variability in the surface flux of sensible and latent heat and of sea salt aerosol may not be required in large scale and global models to describe marine boundary layer cellular cloudiness.

  12. ANGULAR MOMENTUM TRANSPORT BY ACOUSTIC MODES GENERATED IN THE BOUNDARY LAYER. II. MAGNETOHYDRODYNAMIC SIMULATIONS

    SciTech Connect (OSTI)

    Belyaev, Mikhail A.; Rafikov, Roman R.; Stone, James M., E-mail: rrr@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Ivy Lane, Princeton, NJ 08540 (United States)

    2013-06-10T23:59:59.000Z

    We perform global unstratified three-dimensional magnetohydrodynamic simulations of an astrophysical boundary layer (BL)-an interface region between an accretion disk and a weakly magnetized accreting object such as a white dwarf-with the goal of understanding the effects of magnetic field on the BL. We use cylindrical coordinates with an isothermal equation of state and investigate a number of initial field geometries including toroidal, vertical, and vertical with zero net flux. Our initial setup consists of a Keplerian disk attached to a non-rotating star. In a previous work, we found that in hydrodynamical simulations, sound waves excited by shear in the BL were able to efficiently transport angular momentum and drive mass accretion onto the star. Here we confirm that in MHD simulations, waves serve as an efficient means of angular momentum transport in the vicinity of the BL, despite the magnetorotational instability (MRI) operating in the disk. In particular, the angular momentum current due to waves is at times larger than the angular momentum current due to MRI. Our results suggest that angular momentum transport in the BL and its vicinity is a global phenomenon occurring through dissipation of waves and shocks. This point of view is quite different from the standard picture of transport by a local anomalous turbulent viscosity. In addition to angular momentum transport, we also study magnetic field amplification within the BL. We find that the field is indeed amplified in the BL, but only by a factor of a few, and remains subthermal.

  13. Stability and Turbulence in the Atmospheric Boundary Layer: A Comparison of Remote Sensing and Tower Observations

    SciTech Connect (OSTI)

    Friedrich, K.; Lundquist, J. K.; Aitken, M.; Kalina, E. A.; Marshall, R. F.

    2012-01-01T23:59:59.000Z

    When monitoring winds and atmospheric stability for wind energy applications, remote sensing instruments present some advantages to in-situ instrumentation such as larger vertical extent, in some cases easy installation and maintenance, measurements of vertical humidity profiles throughout the boundary layer, and no restrictions on prevailing wind directions. In this study, we compare remote sensing devices, Windcube lidar and microwave radiometer, to meteorological in-situ tower measurements to demonstrate the accuracy of these measurements and to assess the utility of the remote sensing instruments in overcoming tower limitations. We compare temperature and wind observations, as well as calculations of Brunt-Vaisala frequency and Richardson numbers for the instrument deployment period in May-June 2011 at the U.S. Department of Energy National Renewable Energy Laboratory's National Wind Technology Center near Boulder, Colorado. The study reveals that a lidar and radiometer measure wind and temperature with the same accuracy as tower instruments, while also providing advantages for monitoring stability and turbulence. We demonstrate that the atmospheric stability is determined more accurately when the liquid-water mixing ratio derived from the vertical humidity profile is considered under moist-adiabatic conditions.

  14. Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign

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

    Zhou, Xiaoli; Kollias, Pavlos; Lewis, Ernie R.

    2015-03-01T23:59:59.000Z

    The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporatedmore »before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)« less

  15. Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign

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

    Zhou, Xiaoli [McGill Univ., Montreal, Quebec (Canada); Dept. of Atmospheric and Oceanic Sciences; Kollias, Pavlos [McGill Univ., Montreal, Quebec (Canada); Dept. of Atmospheric and Oceanic Sciences; Lewis, Ernie R. [Brookhaven National Lab., Upton, NY (United States). Biological, Environmental, and Climate Sciences Dept.

    2015-03-01T23:59:59.000Z

    The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporated before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)

  16. PLASMOID RELEASES IN THE HELIOSPHERIC CURRENT SHEET AND ASSOCIATED CORONAL HOLE BOUNDARY LAYER EVOLUTION

    SciTech Connect (OSTI)

    Foullon, C. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Lavraud, B.; Opitz, A.; Sauvaud, J.-A. [Institut de Recherche en Astrophysique et Planetologie (IRAP), Universite de Toulouse (UPS) and Centre National de la Recherche Scientifique, UMR 5277, Toulouse (France); Luhmann, J. G. [Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720 (United States); Farrugia, C. J.; Simunac, K. D. C.; Galvin, A. B.; Kucharek, H.; Popecki, M. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Retino, A. [Laboratoire de Physique des Plasmas-CNRS, Observatoire de Saint-Maur, 4 avenue de Neptune, Saint-Maur-Des-Fosses, 94107 (France); Wardle, N. C.; Owen, C. J., E-mail: claire.foullon@warwick.ac.uk [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom)

    2011-08-10T23:59:59.000Z

    As the heliospheric current sheet (HCS) is corotating past STEREO-B, near-Earth spacecraft ACE, Wind and Cluster, and STEREO-A over more than three days between 2008 January 10 and 14, we observe various sections of (near-pressure-balanced) flux-rope- and magnetic-island-type plasmoids in the associated heliospheric plasma sheet (HPS). The plasmoids can qualify as slow interplanetary coronal mass ejections and are relatively low proton beta (<0.5) structures, with small length scales (an order of magnitude lower than typical magnetic cloud values) and low magnetic field strengths (2-8 nT). One of them, in particular, detected at STEREO-B, corresponds to the first reported evidence of a detached plasmoid in the HPS. The in situ signatures near Earth are associated with a long-decay X-ray flare and a slow small-scale streamer ejecta, observed remotely with white-light coronagraphs aboard STEREO-B and SOHO and tracked by triangulation. Before the arrival of the HPS, a coronal hole boundary layer (CHBL) is detected in situ. The multi-spacecraft observations indicate a CHBL stream corotating with the HCS but with a decreasing speed distribution suggestive of a localized or transient nature. While we may reasonably assume that an interaction between ejecta and CHBL provides the source of momentum for the slow ejecta's acceleration, the outstanding composition properties of the CHBL near Earth provide here circumstantial evidence that this interaction or possibly an earlier one, taking place during streamer swelling when the ejecta rises slowly, results in additional mixing processes.

  17. Retrieval of Urban Boundary Layer Structures from Doppler Lidar Data. Part I: Accuracy Assessment

    SciTech Connect (OSTI)

    Xia, Quanxin; Lin, Ching Long; Calhoun, Ron; Newsom, Rob K.

    2008-01-01T23:59:59.000Z

    Two coherent Doppler lidars from the US Army Research Laboratory (ARL) and Arizona State University (ASU) were deployed in the Joint Urban 2003 atmospheric dispersion field experiment (JU2003) held in Oklahoma City. The dual lidar data are used to evaluate the accuracy of the four-dimensional variational data assimilation (4DVAR) method and identify the coherent flow structures in the urban boundary layer. The objectives of the study are three-fold. The first objective is to examine the effect of eddy viscosity models on the quality of retrieved velocity data. The second objective is to determine the fidelity of single-lidar 4DVAR and evaluate the difference between single- and dual-lidar retrievals. The third objective is to correlate the retrieved flow structures with the ground building data. It is found that the approach of treating eddy viscosity as part of control variables yields better results than the approach of prescribing viscosity. The ARL single-lidar 4DVAR is able to retrieve radial velocity fields with an accuracy of 98% in the along-beam direction and 80-90% in the cross-beam direction. For the dual-lidar 4DVAR, the accuracy of retrieved radial velocity in the ARL cross-beam direction improves to 90-94%. By using the dual-lidar retrieved data as a reference, the single-lidar 4DVAR is able to recover fluctuating velocity fields with 70-80% accuracy in the along-beam direction and 60-70% accuracy in the cross-beam direction. Large-scale convective roll structures are found in the vicinity of downtown airpark and parks. Vortical structures are identified near the business district. Strong updrafts and downdrafts are also found above a cluster of restaurants.

  18. Collaborative Research: ARM observations for the development and evaluation of models and parameterizations of cloudy boundary layers

    SciTech Connect (OSTI)

    Albrecht, Bruce,

    2013-07-12T23:59:59.000Z

    This is a collaborative project with Dr. Ping Zhu at Florida International University. It was designed to address key issues regarding the treatment of boundary layer cloud processes in climate models with UM’s research focusing on the analyses of ARM cloud radar observations from MMCR and WACR and FIU’s research focusing on numerical simulations of boundary layer clouds. This project capitalized on recent advancements in the ARM Millimeter Cloud Radar (MMCR) processing and the development of the WACR (at the SGP) to provide high temporal and spatial resolution Doppler cloud radar measurements for characterizing in-cloud turbulence, large-eddy circulations, and high resolution cloud structures of direct relevance to high resolution numerical modeling studies. The principal focus of the observational component of this collaborative study during this funding period was on stratocumulus clouds over the SGP site and fair-weather cumuli over the Nauru site. The statistical descriptions of the vertical velocity structures in continental stratocumulus clouds and in the Nauru shallow cumuli that are part of this study represents the most comprehensive observations of the vertical velocities in boundary layer clouds to date and were done in collaboration with Drs. Virendra Ghate and Pavlos Kollias.

  19. Vehicle cabin cooling system for capturing and exhausting heated boundary layer air from inner surfaces of solar heated windows

    DOE Patents [OSTI]

    Farrington, Robert B. (Golden, CO); Anderson, Ren (Broomfield, CO)

    2001-01-01T23:59:59.000Z

    The cabin cooling system includes a cooling duct positioned proximate and above upper edges of one or more windows of a vehicle to exhaust hot air as the air is heated by inner surfaces of the windows and forms thin boundary layers of heated air adjacent the heated windows. The cabin cooling system includes at least one fan to draw the hot air into the cooling duct at a flow rate that captures the hot air in the boundary layer without capturing a significant portion of the cooler cabin interior air and to discharge the hot air at a point outside the vehicle cabin, such as the vehicle trunk. In a preferred embodiment, the cooling duct has a cross-sectional area that gradually increases from a distal point to a proximal point to the fan inlet to develop a substantially uniform pressure drop along the length of the cooling duct. Correspondingly, this cross-sectional configuration develops a uniform suction pressure and uniform flow rate at the upper edge of the window to capture the hot air in the boundary layer adjacent each window.

  20. MOMENTUM AND THERMAL BOUNDARY-LAYER THICKNESS IN A STAGNATION FLOW CHEMICAL VAPOR DEPOSITION REACTOR

    E-Print Network [OSTI]

    Dandy, David

    REACTOR DAVID S. DANDY AND JUNGHEUM YUN Department of Chemical Engineering Colorado State University Fort deposition pedestal reactors. Expressions for the velocity and temperature profiles within the boundary

  1. MEMS Pressure Sensor Array for Aeroacoustic Analysis of the Turbulent Boundary Layer

    E-Print Network [OSTI]

    White, Robert D.

    holes Density of air c Speed of sound µ Viscosity of air 1 Density of diaphragm (Polysilicon) E1 Modulus of elasticity of diaphragm 1 Poisson's ratio of diaphragm t2 Thickness of Parylene-C layer 2 Density of Parylene-C layer E2 Modulus of elasticity of Parylene-C layer Research Assistant, Department

  2. Friction of a slider on a granular layer: Non-monotonic thickness dependence and effect of boundary conditions

    E-Print Network [OSTI]

    Saloome Siavoshi; Ashish V. Orpe; Arshad Kudrolli

    2005-12-22T23:59:59.000Z

    We investigate the effective friction encountered by a mass sliding on a granular layer as a function of bed thickness and boundary roughness conditions. The observed friction has minima for a small number of layers before it increases and saturates to a value which depends on the roughness of the sliding surface. We use an index-matched interstitial liquid to probe the internal motion of the grains with fluorescence imaging in a regime where the liquid has no significant effect on the measured friction. The shear profiles obtained as a function of depth show decrease in slip near the sliding surface as the layer thickness is increased. We propose that the friction depends on the degree of grain confinement relative to the sliding surfaces.

  3. RACORO continental boundary layer cloud investigations. Part I: Case study development and ensemble large-scale forcings

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

    Vogelmann, Andrew M.; Fridlind, Ann M.; Toto, Tami; Endo, Satoshi; Lin, Wuyin; Wang, Jian; Feng, Sha; Zhang, Yunyan; Turner, David D.; Liu, Yangang; et al

    2015-05-01T23:59:59.000Z

    Observation-based modeling case studies of continental boundary layer clouds have been developed to study cloudy boundary layers, aerosol influences upon them, and their representation in cloud- and global-scale models. Three 60-hour case study periods span the temporal evolution of cumulus, stratiform, and drizzling boundary layer cloud systems, representing mixed and transitional states rather than idealized or canonical cases. Based on in-situ measurements from the RACORO field campaign and remote-sensing observations, the cases are designed with a modular configuration to simplify use in large-eddy simulations (LES) and single-column models. Aircraft measurements of aerosol number size distribution are fit to lognormal functionsmore »for concise representation in models. Values of the aerosol hygroscopicity parameter, ?, are derived from observations to be ~0.10, which are lower than the 0.3 typical over continents and suggestive of a large aerosol organic fraction. Ensemble large-scale forcing datasets are derived from the ARM variational analysis, ECMWF forecasts, and a multi-scale data assimilation system. The forcings are assessed through comparison of measured bulk atmospheric and cloud properties to those computed in 'trial' large-eddy simulations, where more efficient run times are enabled through modest reductions in grid resolution and domain size compared to the full-sized LES grid. Simulations capture many of the general features observed, but the state-of-the-art forcings were limited at representing details of cloud onset, and tight gradients and high-resolution transients of importance. Methods for improving the initial conditions and forcings are discussed. The cases developed are available to the general modeling community for studying continental boundary clouds.« less

  4. Seismic and gravitational studies of melting in the mantle's thermal boundary layers

    E-Print Network [OSTI]

    Van Ark, Emily M

    2007-01-01T23:59:59.000Z

    This thesis presents three studies which apply geophysical tools to the task of better understanding mantle melting phenomena at the upper and lower boundaries of the mantle. The first study uses seafloor bathymetry and ...

  5. The Effects of Step Excrescences on Swept-Wing Boundary-Layer Transition

    E-Print Network [OSTI]

    Duncan, Jr., Glen T.

    2014-08-12T23:59:59.000Z

    flutter and handling-quality clearance flight proved the new test article is safe for the flight-testing experiments. Pressure measurements are compared with computational results, infrared thermography is used to globally detect boundary...

  6. Establishment of a research facility for investigating the effects of unsteady inlet flow, pressure gradient and curvature on boundary layer development, wake development and heat transfer

    E-Print Network [OSTI]

    Pardivala, Darayus Noshir

    1991-01-01T23:59:59.000Z

    ESTABLISHMENT OF A RESEARCH FACILITY FOR INVESTIGATING THE EFFECTS OF UNSTEADY INLET FLOW) PRESSURE GRADIENT AND CURVATURE ON BOUNDARY LAYER DEVELOPMENT) %'AKE DEVELOPMENT AND HEAT TRANSFER A Thesis by DARAYUS NOSHIR PARDIVALA Submitted... THE EFFECTS OF UNSTEADY INLET FLOW, PRESSURE GRADIENT AND CURVATURE ON BOUNDARY LAYER DEVELOPMENT, WAKE DEVELOPMENT AND HEAT TRANSFER A Thesis by DARAYUS NOSHIR PARDIVALA Approved as to style and content by: Taher Schobeiri (Chair of Committee) Gerald...

  7. On the use of a nascent delta function in radiative-transfer calculations for multi-layer media subject to Fresnel boundary

    E-Print Network [OSTI]

    Siewert, Charles E.

    subject to Fresnel boundary and interface conditions R.D.M. Garcia a,Ã, C.E. Siewert b a Instituto de: Radiative transfer Nascent delta function Fresnel conditions Discrete-ordinates method a b s t r a c in a plane-parallel, multi-layer medium subject to Fresnel boundary and interface conditions. As a result

  8. MEMS Pressure Sensor Array for Aeroacoustic Analysis of the Turbulent Boundary Layer

    E-Print Network [OSTI]

    White, Robert D.

    vent holes Cc Center­to­center spacing of vent holes Density of air c Speed of sound µ Viscosity of air 1 Density of diaphragm (Polysilicon) E1 Modulus of elasticity of diaphragm 1 Poisson's ratio Density of Parylene-C layer E2 Modulus of elasticity of Parylene-C layer 2 Poisson's ratio of Parylene

  9. On the thermodynamic boundary conditions of a solidifying mushy layer with outflow

    E-Print Network [OSTI]

    Rees Jones, David W.; Worster, M. Grae

    2014-11-27T23:59:59.000Z

    –207. Thermodynamic boundary conditions with outflow 11 Beckermann, C. & Wang, C.Y. 1995 Multiphase/-scale modeling of alloy solidification. In Annual Reviews of Heat Transfer (ed. C. L. Tien), vol. 6, pp. 115–198. Begell House. Conroy, D. & Worster, M. G. 2006 Mush...

  10. Use of shear-stress-sensitive, temperature-insensitive liquid crystals for hypersonic boundary-layer transition detection

    SciTech Connect (OSTI)

    Aeschliman, D.P.; Croll, R.H.; Kuntz, D.W.

    1997-04-01T23:59:59.000Z

    The use of shear-stress-sensitive, temperature-insensitive (SSS/TI) liquid crystals (LCs) has been evaluated as a boundary-layer transition detection technique for hypersonic flows. Experiments were conducted at Mach 8 in the Sandia National Laboratories Hypersonic Wind Tunnel using a flat plate model at near zero-degree angle of attack over the freestream unit Reynolds number range 1.2-5.8x10{sup 6}/ft. Standard 35mm color photography and Super VHS color video were used to record LC color changes due to varying surface shear stress during the transition process for a range of commercial SSS liquid crystals. Visual transition data were compared to an established method using calorimetric surface heat-transfer measurements to evaluate the LC technique. It is concluded that the use of SSS/TI LCs can be an inexpensive, safe, and easy to use boundary-layer transition detection method for hypersonic flows. However, a valid interpretation of the visual records requires careful attention to illumination intensity levels and uniformity, lighting and viewing angles, some prior understanding of the general character of the flow, and the selection of the appropriate liquid crystal for the particular flow conditions.

  11. Wake Turbulence of Two NREL 5-MW Wind Turbines Immersed in a Neutral Atmospheric Boundary-Layer Flow

    E-Print Network [OSTI]

    Bashioum, Jessica L; Schmitz, Sven; Duque, Earl P N

    2013-01-01T23:59:59.000Z

    The fluid dynamics video considers an array of two NREL 5-MW turbines separated by seven rotor diameters in a neutral atmospheric boundary layer (ABL). The neutral atmospheric boundary-layer flow data were obtained from a precursor ABL simulation using a Large-Eddy Simulation (LES) framework within OpenFOAM. The mean wind speed at hub height is 8m/s, and the surface roughness is 0.2m. The actuator line method (ALM) is used to model the wind turbine blades by means of body forces added to the momentum equation. The fluid dynamics video shows the root and tip vortices emanating from the blades from various viewpoints. The vortices become unstable and break down into large-scale turbulent structures. As the wakes of the wind turbines advect further downstream, smaller-scale turbulence is generated. It is apparent that vortices generated by the blades of the downstream wind turbine break down faster due to increased turbulence levels generated by the wake of the upstream wind turbine.

  12. A novel Whole Air Sample Profiler (WASP) for the quantification of volatile organic compounds in the boundary layer

    SciTech Connect (OSTI)

    Mak, J. E.; Su, L.; Guenther, Alex B.; Karl, Thomas G.

    2013-10-16T23:59:59.000Z

    The emission and fate of reactive VOCs is of inherent interest to those studying chemical biosphere-atmosphere interactions. In-canopy VOC observations are obtainable using tower-based samplers, but the lack of suitable sampling systems for the full boundary 5 layer has limited the data characterizing the vertical structure of such gases above the canopy height and still in the boundary layer. This is the important region where many reactive VOCs are oxidized or otherwise removed. Here we describe an airborne sampling system designed to collect a vertical profile of air into a 3/800 OD tube 150m in length. The inlet ram air pressure is used to flow sampled air through the 10 tube, which results in a varying flow rate based on aircraft speed and altitude. Since aircraft velocity decreases during ascent, it is necessary to account for the variable flow rate into the tube. This is accomplished using a reference gas that is pulsed into the air stream so that the precise altitude of the collected air can be reconstructed post-collection. The pulsed injections are also used to determine any significant effect 15 from diffusion/mixing within the sampling tube, either during collection or subsequent extraction for gas analysis. This system has been successfully deployed, and we show some measured vertical profiles of isoprene and its oxidation products methacrolein and methyl vinyl ketone from a mixed canopy near Columbia, Missouri.

  13. Modeling feedbacks between a boreal forest and the planetary boundary layer

    E-Print Network [OSTI]

    observations at the stand scale (e.g., flux towers) and those at larger scales, e.g., airborne or satellite on the atmospheric surface layer by 21% for latent energy, 64% for air temperature, and 44% for water mixing ratio to the biosphere through the surface energy balance. The response of the terrestrial biosphere to climate

  14. The Effects of Step Excrescences on Swept-Wing Boundary-Layer Transition 

    E-Print Network [OSTI]

    Duncan, Jr., Glen T.

    2014-08-12T23:59:59.000Z

    of an unswept model of similar 2-D pressure gradient. The crossflow instability is believed to dominate the transition process up to the critical step height, while the shear-layer instability dominates after the critical step height. The critical step height...

  15. Confinement of the Sun's interior magnetic field: some exact boundary-layer solutions

    E-Print Network [OSTI]

    T. S. Wood; M. E. McIntyre

    2007-09-10T23:59:59.000Z

    High-latitude laminar confinement of the Sun's interior magnetic field is shown to be possible, as originally proposed by Gough and McIntyre (1998) but contrary to a recent claim by Brun and Zahn (A&A 2006). Mean downwelling as weak as 2x10^-6cm/s -- gyroscopically pumped by turbulent stresses in the overlying convection zone and/or tachocline -- can hold the field in advective-diffusive balance within a confinement layer of thickness scale ~ 1.5Mm ~ 0.002 x (solar radius) while transmitting a retrograde torque to the Ferraro-constrained interior. The confinement layer sits at the base of the high-latitude tachocline, near the top of the radiative envelope and just above the `tachopause' marking the top of the helium settling layer. A family of exact, laminar, frictionless, axisymmetric confinement-layer solutions is obtained for uniform downwelling in the limit of strong rotation and stratification. A scale analysis shows that the flow is dynamically stable and the assumption of laminar flow realistic. The solution remains valid for downwelling values of the order of 10^-5cm/s but not much larger. This suggests that the confinement layer may be unable to accept a much larger mass throughput. Such a restriction would imply an upper limit on possible internal field strengths, perhaps of the order of hundreds of gauss, and would have implications also for ventilation and lithium burning. The solutions have interesting chirality properties not mentioned in the paper owing to space restrictions, but described at http://www.atmos-dynamics.damtp.cam.ac.uk/people/mem/papers/SQBO/solarfigure.html

  16. Boundary Layer The U.S. Department of Energy's Atmospheric Radiation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced Materials Find FindRewindParticleBorn on anJeffersonBound Boundary

  17. Squeezout phenomena and boundary layer formation of a model ionic liquid under confinement and charging

    E-Print Network [OSTI]

    R. Capozza; A. Vanossi; A. Benassi; E. Tosatti

    2014-12-22T23:59:59.000Z

    Electrical charging of parallel plates confining a model ionic liquid down to nanoscale distances yields a variety of charge-induced changes in the structural features of the confined film. That includes even-odd switching of the structural layering and charging-induced solidification and melting, with important changes of local ordering between and within layers, and of squeezout behavior. By means of molecular dynamics simulations, we explore this variety of phenomena in the simplest charged Lennard-Jones coarse-grained model including or excluding the effect a neutral tail giving an anisotropic shape to one of the model ions. Using these models and open conditions permitting the flow of ions in and out of the interplate gap, we simulate the liquid squeezout to obtain the distance dependent structure and forces between the plates during their adiabatic appraoch under load. Simulations at fixed applied force illustrate an effective electrical pumping of the ionic liquid, from a thick nearly solid film that withstands the interplate pressure for high plate charge to complete squeezout following melting near zero charge. Effective enthalpy curves obtained by integration of interplate forces versus distance show the local minima that correspond to layering, and predict the switching between one minimum and another under squeezing and charging.

  18. Stress concentration near stiff inclusions: validation of rigid inclusion model and boundary layers by means of photoelasticity

    E-Print Network [OSTI]

    Diego Misseroni; Francesco Dal Corso; Summer Shahzad; Davide Bigoni

    2014-04-03T23:59:59.000Z

    Photoelasticity is employed to investigate the stress state near stiff rectangular and rhombohedral inclusions embedded in a 'soft' elastic plate. Results show that the singular stress field predicted by the linear elastic solution for the rigid inclusion model can be generated in reality, with great accuracy, within a material. In particular, experiments: (i.) agree with the fact that the singularity is lower for obtuse than for acute inclusion angles; (ii.) show that the singularity is stronger in Mode II than in Mode I (differently from a notch); (iii.) validate the model of rigid quadrilateral inclusion; (iv.) for thin inclusions, show the presence of boundary layers deeply influencing the stress field, so that the limit case of rigid line inclusion is obtained in strong dependence on the inclusion's shape. The introduced experimental methodology opens the possibility of enhancing the design of thin reinforcements and of analyzing complex situations involving interaction between inclusions and defects.

  19. Ice at the Interface: Atmosphere-Ice-Ocean Boundary Layer Processes and Their Role in Polar Change---Workshop Report

    SciTech Connect (OSTI)

    Hunke, Elizabeth C. [Los Alamos National Laboratory

    2012-07-23T23:59:59.000Z

    The atmosphere-ocean boundary layer in which sea ice resides includes many complex processes that require a more realistic treatment in GCMs, particularly as models move toward full earth system descriptions. The primary purpose of the workshop was to define and discuss such coupled processes from observational and modeling points of view, including insight from both the Arctic and Antarctic systems. The workshop met each of its overarching goals, including fostering collaboration among experimentalists, theorists and modelers, proposing modeling strategies, and ascertaining data availability and needs. Several scientific themes emerged from the workshop, such as the importance of episodic or extreme events, precipitation, stratification above and below the ice, and the marginal ice zone, whose seasonal Arctic migrations now traverse more territory than in the past.

  20. Influence of surface heating on the boundary layer stability of flows with favorable pressure gradients

    E-Print Network [OSTI]

    Landrum, David Brian

    1986-01-01T23:59:59.000Z

    $ of its chord heated to about 1. 5 times the adiabatic temperature. Compared to the adiabatic case, the nose heating slightly delayed the initial amplification of disturbances and significantly incr eased the transition length. A vertical traverse... . . . . 10 Fig. 3 Neutral stability cur ve f' or a typical boundar y layer velocity profile 13 Fig. 4a Falkner-Skan velocity profiles with wall heating, 8 0. 0 18 Fig. 4b Falkner-Skan temperature profiles, B=O. O 19 Fig. 5a Falkner-Skan velocity prof...

  1. An investigation of the diabatic wind profile in the atmospheric boundary layer

    E-Print Network [OSTI]

    O'Brien, James Joseph

    1964-01-01T23:59:59.000Z

    in the study; in particular, thanks are extended to Mr. B. Jesse Eckalkamp for his assistance, Mrs. Linda Alexander for typing the final copy, and Mrs. Maxine Pulaski for drafting the figures. The National Space and Aeronautics Administration must...; and the potential temperature at the surface, 8 . After M & 0, the scale 0 length is derived from these quantities by letting Ue be used in place of r /o and H/pc be used in the place of H. since 8 varies little 0 P in the layer concerned, it may be regarded as a...

  2. Boundary layer (shear-band) in frustrated viscoplastic flows T. CHEVALIER, S. RODTS, X. CHATEAU, J. BOUJLEL, M. MAILLARD, P. COUSSOT

    E-Print Network [OSTI]

    Boyer, Edmond

    (paints, mortars, concrete, drilling fluids) in food industry and cooking (purees, sauces, dough stress fluids give rise to a boundary layer, which takes the form of a liquid region of uniform stress fluids such as concentrated colloids, emul- sions, foams, are jammed systems which behave as liq

  3. TRANSPORT OF HEAT, WATER VAPOR AND CARBON DOXIDE BY LONG PERIOD EDDIES IN THE STABLE BOUNDARY LAYER

    SciTech Connect (OSTI)

    Kurzeja, R.

    2010-07-26T23:59:59.000Z

    The vertical transport of heat and trace chemicals for a night in April has been studied with a wavelet analysis and conventional one-hour averages. It was found that for the night of April 20, 2009, turbulent kinetic energy, heat and trace chemicals were transported directed downward from the jet core. The most significant periods for this transport were less than 5 minutes and greater than one hour with intermittent transport taking place in the 5 min to 1 hour time frame. The nocturnal boundary layer is characterized by turbulent intermittency, long period oscillations, and a slow approach to equilibrium, (Mahrt, 1999). Although turbulence is usually maintained by surface friction, downward transport from low-level jets can also play an important role in turbulence maintenance and in the transport of scalars, Mahrt (1999), Banta et al. (2006). The eddy covariance flux measurement technique assumes continuous turbulence which is unusual in the stable boundary because significant flux transport occurs via turbulent eddies whose periods are long compared with the averaging time (Goulden et al., 1996). Systematic error in eddy flux measurements is attributed mainly to the neglect of long period eddies. Banta et al. (2006) noted that observations of turbulence below the low level jet suggested that while upward transport of turbulence kinetic energy (TKE) is common, downward transport from the jet can also occur. They found that in the CASES 99 experiments that turbulence scaled well with the strength of the low-level jet, and that surface cooling was more important than surface roughness. Because nocturnal turbulence is intermittent and non-stationary, the appropriate averaging time for calculation of TKE and EC fluxes is not obvious. Wavelet analysis is, thus, a more suitable analysis tool than conventional Fourier analysis.

  4. Horizontal-Velocity and Variance Measurements in the Stable Boundary Layer Using Doppler Lidar: Sensitivity to Averaging Procedures

    SciTech Connect (OSTI)

    Pichugina, Yelena L.; Banta, Robert M.; Kelley, Neil D.; Jonkman, Bonnie J.; Tucker, Sara C.; Newsom, Rob K.; Brewer, W. A.

    2008-08-01T23:59:59.000Z

    Quantitative data on turbulence variables aloft--above the region of the atmosphere conveniently measured from towers--has been an important but difficult measurement need for advancing understanding and modeling of the stable boundary layer (SBL). Vertical profiles of streamwise velocity variances obtained from NOAA’s High Resolution Doppler Lidar (HRDL), which have been shown to be numerically equivalent to turbulence kinetic energy (TKE) for stable conditions, are a measure of the turbulence in the SBL. In the present study, the mean horizontal wind component U and variance ?u2 were computed from HRDL measurements of the line-of-sight (LOS) velocity using a technique described in Banta, et al. (2002). The technique was tested on datasets obtained during the Lamar Low-Level Jet Project (LLLJP) carried out in early September 2003, near the town of Lamar in southeastern Colorado. This paper compares U with mean wind speed obtained from sodar and sonic anemometer measurements. It then describes several series of averaging tests that produced the best correlation between TKE calculated from sonic anemometer data at several tower levels and lidar measurements of horizontal velocity variance ?u2. The results show high correlation (0.71-0.97) of the mean U and average wind speed measured by sodar and in-situ instruments, independent of sampling strategies and averaging procedures. Comparison of estimates of variance, on the other hand, proved sensitive to both the spatial and temporal averaging techniques.

  5. Transitions of cloud-topped marine boundary layers characterized by AIRS, MODIS, and a large eddy simulation model

    SciTech Connect (OSTI)

    Yue, Qing; Kahn, Brian; Xiao, Heng; Schreier, Mathias; Fetzer, E. J.; Teixeira, J.; Suselj, Kay

    2013-08-16T23:59:59.000Z

    Cloud top entrainment instability (CTEI) is a hypothesized positive feedback between entrainment mixing and evaporative cooling near the cloud top. Previous theoretical and numerical modeling studies have shown that the persistence or breakup of marine boundary layer (MBL) clouds may be sensitive to the CTEI parameter. Collocated thermodynamic profile and cloud observations obtained from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments are used to quantify the relationship between the CTEI parameter and the cloud-topped MBL transition from stratocumulus to trade cumulus in the northeastern Pacific Ocean. Results derived from AIRS and MODIS are compared with numerical results from the UCLA large eddy simulation (LES) model for both well-mixed and decoupled MBLs. The satellite and model results both demonstrate a clear correlation between the CTEI parameter and MBL cloud fraction. Despite fundamental differences between LES steady state results and the instantaneous snapshot type of observations from satellites, significant correlations for both the instantaneous pixel-scale observations and the long-term averaged spatial patterns between the CTEI parameter and MBL cloud fraction are found from the satellite observations and are consistent with LES results. This suggests the potential of using AIRS and MODIS to quantify global and temporal characteristics of the cloud-topped MBL transition.

  6. Boundary Layer Lubrication

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

    refinement of scuffing model to include all classes of materials, especially ceramics and thin-film coatings. Redesign and refine the x-ray accessible tribometer for in-situ study...

  7. Intercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed during SHEBA/FIRE-ACE

    SciTech Connect (OSTI)

    Morrison, H.; Zuidema, Paquita; Ackerman, Andrew; Avramov, Alexander; de Boer, Gijs; Fan, Jiwen; Fridlind, Ann; Hashino, Tempei; Harrington, Jerry Y.; Luo, Yali; Ovchinnikov, Mikhail; Shipway, Ben

    2011-06-16T23:59:59.000Z

    An intercomparison of six cloud-resolving and large-eddy simulation models is presented. This case study is based on observations of a persistent mixed-phase boundary layer cloud gathered on 7 May, 1998 from the Surface Heat Budget of Arctic Ocean (SHEBA) and First ISCCP Regional Experiment - Arctic Cloud Experiment (FIRE-ACE). Ice nucleation is constrained in the simulations in a way that holds the ice crystal concentration approximately fixed, with two sets of sensitivity runs in addition to the baseline simulations utilizing different specified ice nucleus (IN) concentrations. All of the baseline and sensitivity simulations group into two distinct quasi-steady states associated with either persistent mixed-phase clouds or all-ice clouds after the first few hours of integration, implying the existence of multiple equilibria. These two states are associated with distinctly different microphysical, thermodynamic, and radiative characteristics. Most but not all of the models produce a persistent mixed-phase cloud qualitatively similar to observations using the baseline IN/crystal concentration, while small increases in the IN/crystal concentration generally lead to rapid glaciation and conversion to the all-ice state. Budget analysis indicates that larger ice deposition rates associated with increased IN/crystal concentrations have a limited direct impact on dissipation of liquid in these simulations. However, the impact of increased ice deposition is greatly enhanced by several interaction pathways that lead to an increased surface precipitation flux, weaker cloud top radiative cooling and cloud dynamics, and reduced vertical mixing, promoting rapid glaciation of the mixed-phase cloud for deposition rates in the cloud layer greater than about 1-2x10-5 g kg-1 s-1. These results indicate the critical importance of precipitation-radiative-dynamical interactions in simulating cloud phase, which have been neglected in previous fixed-dynamical parcel studies of the cloud phase parameter space. Large sensitivity to the IN/crystal concentration also suggests the need for improved understanding of ice nucleation and its parameterization in models.

  8. A one-dimensional sectional model to simulate multicomponent aerosol dynamics in the marine boundary layer 1. Model description

    SciTech Connect (OSTI)

    Fitzgerald, J.W.; Hoppel, W.A. [Remote Sensing Division, Naval Research Laboratory, Washington, District of Columbia (United States)] [Remote Sensing Division, Naval Research Laboratory, Washington, District of Columbia (United States); Gelbard, F. [Modeling and Analysis Department, Sandia National Laboratories, Albuquerque, New Mexico (United States)] [Modeling and Analysis Department, Sandia National Laboratories, Albuquerque, New Mexico (United States)

    1998-07-01T23:59:59.000Z

    A one-dimensional, multicomponent sectional model has been developed to simulate the temporal and vertical variations of the aerosol size distribution and composition in the marine boundary layer (MBL). An important aspect of the model is its ability to handle the transport of aerosols in an atmosphere with humidity gradients with no numerical diffusion caused by the swelling and shrinking of the particles as they move through the humidity gradients. This is achieved by rewriting the aerosol general dynamical equation (GDE) in terms of dry radius thus transferring all variations in radius caused by temporal and spatial humidity variations to the rate coefficients appearing in the equations. The model then solves the new GDE in fixed dry size sections, with the humidity dependence of the processes now included in variable coefficients. This procedure also results in correct gradient transport. A limiting assumption is that the particles equilibrate instantaneously with the ambient water vapor. This assumption limits the maximum particle size which can be treated in the model to ambient (wet) radii less than about 30 {mu}m. All processes currently believed to be important in shaping the MBL size distribution are included in the current version of the model. These include generation of sea-salt aerosol at the ocean surface, nucleation of new particles, coagulation, growth due to condensation of gas-phase reaction products, growth due to sulfate formation during cloud processing, precipitation scavenging, surface deposition, turbulent mixing, gravitational settling, and exchange with the free troposphere. Simple gas-phase chemistry which includes the oxidation of dimethylsulfide and SO{sub 2} to sulfate is incorporated in the current version of the model. {copyright} 1998 American Geophysical Union

  9. Mars Exploration Rover (MER) Panoramic Camera (Pancam) Twilight Image Analysis for Determination of Planetary Boundary Layer and Dust Particle Size Parameters

    E-Print Network [OSTI]

    Grounds, Stephanie Beth

    2012-02-14T23:59:59.000Z

    to take surface-based measurements to offer support for dust and boundary layer measurements made from remote sensors (Lemmon et al., 2004a). Mars has different atmospheric characteristics from those on Earth. For example, the solar constant for Mars... is approximately 44% of the value for Earth (varying by approximately 20%), and the temperature ranges on Mars (- 125?C to +25?C) slightly ____________ This thesis follows the style of the Journal of Geophysical Research. 2 overlap those on Earth (- 80?C...

  10. Nitrogen Oxides in the Nocturnal Boundary Layer: Chemistry of Nitrous Acid (HONO) and the Nitrate Radical (N03)

    SciTech Connect (OSTI)

    Jochen Stutz

    2005-05-24T23:59:59.000Z

    Summary Chemical processes occurring at night in the lowest part of the urban atmosphere, the so called nocturnal boundary layer (NBL), can influence the composition of the atmosphere during the night as well as the following day. They may impact the budgets of some of the most important pollutants, such as ozone and nitrogen oxides, as well as influence size and composition of particular matter. Few studies have thus far concentrated on the nocturnal chemistry of the urban NBL, most likely due to the strong influence of vertical transport and mixing, which requires the measurement of trace gas profiles instead of simple point observations. Motivated by our lack of observations and understanding of nocturnal chemistry, the focus of this project was the study of the vertical distribution of trace gases and the altitude dependence of nocturnal chemistry under polluted conditions through field observations and modeling studies. The analysis of three field experiments (TEXAQS, Houston, 2000; Phoenix Sunrise Ozone Experiment, 2001; NAPOX, Boston, 2002), two of which were performed in this project, showed that ozone concentrations typically increase with height in the lowest 150m, while NO2 typically decreases. NO3, the dominant nocturnal radical species, showed much higher concentrations in the upper part of the NBL, and was often not present at the ground. With the help of a one-dimensional chemical transport model, developed in this project, we found that the interaction of ground emissions of NOx and hydrocarbons, together with their vertical transport, is responsible for the vertical profiles. The dominant chemical reactions influencing ozone, NO2 and NO3 are the reaction of ozone and NO3 with freshly emitted NO. Sensitivity studies with our model showed that the magnitude of the trace gas gradients depend both on the emission rates and the vertical stability of the NBL. Observations and model analysis clearly show that nocturnal chemistry in urban areas is altitude dependent. Measurements at one altitude, for example at the ground, where most air quality monitoring stations are located, are not representative for the rest of the NBL. Our model also revealed that radical chemistry is, in general, altitude dependent at night. We distinguish three regions: an unreactive, NO rich, ground layer; an upper, O3 and NO3 dominated layer, and a reactive mixing layer, where RO2 radicals are mixed from aloft with NO from the ground. In this reactive layer an active radical chemistry and elevated OH radical levels can be found. The downward transport of N2O5 and HO2NO2, followed by their thermal decay, was also identified as a radical source in this layer. Our observations also gave insight into the formation of HONO in the NBL. Based on our field experiments we were able to show that the NO2 to HONO conversion was relative humidity dependent. While this fact was well known, we found that it is most likely the uptake of HONO onto surfaces which is R.H. dependent, rather than the NO2 to HONO conversion. This finding led to the proposal of a new NO2 to HONO conversion mechanism, which is based on solid physical chemical principles. Noteworthy is also the observation of enhanced NO2 to HONO conversion during a dust storm event in Phoenix. The final activity in our project investigated the influence of the urban canopy, i.e. building walls and surfaces, on nocturnal chemistry. For the first time the surface area of a city was determined based on a Geographical Information System database of the city of Santa Monica. The surface to volume areas found in this study showed that, in the 2 lower part of the NBL, buildings provide a much larger surface area than the aerosol. In addition, buildings take up a considerable amount of the volume near the ground. The expansion of our model and sensitivity studies based on the Santa Monica data revealed that the surface area of buildings considerably influences HONO levels in urban areas. The volume reduction leads to a decrease of O3 and an increase of NO2 near the ground due to the stronger impact o

  11. Isolating Effects of Water Table Dynamics, Terrain, and Soil Moisture Heterogeneity on the Atmospheric Boundary Layer Using Coupled Models

    E-Print Network [OSTI]

    Rihani, Jehan

    2010-01-01T23:59:59.000Z

    boundary conditions of wind, potential temperature, andvariables such as winds, potential temperature, rainfall,variables such as wind speed, potential temperature, and

  12. Horizontal Velocity and Variance Measurements in the Stable Boundary Layer Using Doppler Lidar: Sensitivity to Averaging Procedures

    SciTech Connect (OSTI)

    Pichugina, Y. L.; Banta, R. M.; Kelley, N. D.; Jonkman, B. J.; Tucker, S. C.; Newsom, R. K.; Brewer, W. A.

    2008-08-01T23:59:59.000Z

    Quantitative data on turbulence variables aloft--above the region of the atmosphere conveniently measured from towers--have been an important but difficult measurement need for advancing understanding and modeling of the stable boundary layer (SBL). Vertical profiles of streamwise velocity variances obtained from NOAA's high-resolution Doppler lidar (HRDL), which have been shown to be approximately equal to turbulence kinetic energy (TKE) for stable conditions, are a measure of the turbulence in the SBL. In the present study, the mean horizontal wind component U and variance {sigma}2u were computed from HRDL measurements of the line-of-sight (LOS) velocity using a method described by Banta et al., which uses an elevation (vertical slice) scanning technique. The method was tested on datasets obtained during the Lamar Low-Level Jet Project (LLLJP) carried out in early September 2003, near the town of Lamar in southeastern Colorado. This paper compares U with mean wind speed obtained from sodar and sonic anemometer measurements. The results for the mean U and mean wind speed measured by sodar and in situ instruments for all nights of LLLJP show high correlation (0.71-0.97), independent of sampling strategies and averaging procedures, and correlation coefficients consistently >0.9 for four high-wind nights, when the low-level jet speeds exceeded 15 m s{sup -1} at some time during the night. Comparison of estimates of variance, on the other hand, proved sensitive to both the spatial and temporal averaging parameters. Several series of averaging tests are described, to find the best correlation between TKE calculated from sonic anemometer data at several tower levels and lidar measurements of horizontal-velocity variance {sigma}{sup 2}{sub u}. Because of the nonstationarity of the SBL data, the best results were obtained when the velocity data were first averaged over intervals of 1 min, and then further averaged over 3-15 consecutive 1-min intervals, with best results for the 10- and 15-min averaging periods. For these cases, correlation coefficients exceeded 0.9. As a part of the analysis, Eulerian integral time scales ({tau}) were estimated for the four high-wind nights. Time series of {tau} through each night indicated erratic behavior consistent with the nonstationarity. Histograms of {tau} showed a mode at 4-5 s, but frequent occurrences of larger {tau} values, mostly between 10 and 100 s.

  13. The chemistry of OH and HO2 radicals in the boundary layer over the tropical Atlantic Ocean

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    fore passing near to the Canary Islands on its way to Capepassing close to the Canary Islands before approaching CapePolarstern north of the Canary Islands. Significant boundary

  14. Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets

    E-Print Network [OSTI]

    Schlegel, Fabrice

    Using high-resolution 3-D vortex simulations, this study seeks a mechanistic understanding of vorticity dynamics in transverse jets at a finite Reynolds number. A full no-slip boundary condition, rigorously formulated in ...

  15. Measurement of Boundary-Layer Temperature Profiles by a Scanning 5-MM Radiometer During the 1999 Winter NSA/AAO Radiometer Exp

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighand Retrievals from a NewCuneo Matthew1, 20121 H( 7 Be,Boundary-Layer

  16. Effect of unsteady wake passing frequency on boundary layer transition on the concave surface of a curved plate

    E-Print Network [OSTI]

    Read, Robert Kevin

    1997-01-01T23:59:59.000Z

    frequencies. The periodic unsteady flow is generated utilizing an unsteady flow research facility with a rotating cascade of rods positioned upstream of the curved plate. The inlet velocity is measured using a X-wire hot-film probe while the unsteady boundary...

  17. Detailed study of the influence of surface misorientation on the density of Anti-Phase Boundaries in 3C-SiC layers grown on (001) silicon

    SciTech Connect (OSTI)

    Jiao, S. [Universite Francois Rabelais, Tours, Laboratoire de Microelectronique de Puissance, 16 rue Pierre et Marie Curie, BP 7155, 37071 Tours Cedex 2 (France); Centre de Recherche sur l'Hetero-Epitaxie et ses Applications CNRS-UPR10, rue Bernard Gregory, 06560 Valbonne (France); Zielinski, M.; Chassagne, T. [NOVASiC, Savoie Technolac, Arche Bat 4, BP 267, 73375 Le Bourget du Lac Cedex (France); Roy, S. [Saint Gobain recherche, 39 Quai Lucien Lefranc 93300 Aubervilliers cedex (France); Michaud, J. F.; Alquier, D. [Universite Francois Rabelais, Tours, Laboratoire de Microelectronique de Puissance, 16 rue Pierre et Marie Curie, BP 7155, 37071 Tours Cedex 2 (France); Portail, M. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications CNRS-UPR10, rue Bernard Gregory, 06560 Valbonne (France)

    2010-11-01T23:59:59.000Z

    In this work we investigated the influence of the Si substrate misorientation and 3C-SiC film thickness on the density of Anti-Phase Boundaries, in order to better understand the mechanism of antiphase domain annihilation. The two highlights in our work are the utilization of [001] orientated Si on-axis wafer with spherical dimples, which gave us access to a continuum of off-cut angles (0 deg. to {approx}11 deg.) and directions, and the deposition of elongated silicon islands on the surface of 3C-SiC epilayers, which improved the detection of APDs by analysis of Scanning Electron Microscopy images. We found that for a given layer thickness the relative surface occupation of one domain increases with the off-cut angle value, leading to single domain film up to a certain angle. This critical value is reduced as the film is thickened.

  18. Interface boundary conditions for dynamic magnetization and spin wave dynamics in a ferromagnetic layer with the interface Dzyaloshinskii-Moriya interaction

    SciTech Connect (OSTI)

    Kostylev, M. [School of Physics, M013, University of Western Australia, Crawley, Perth 6009, Western Australia (Australia)

    2014-06-21T23:59:59.000Z

    In this work, we derive the interface exchange boundary conditions for the classical linear dynamics of magnetization in ferromagnetic layers with the interface Dzyaloshinskii-Moriya interaction (IDMI). We show that IDMI leads to pinning of dynamic magnetization at the interface. An unusual peculiarity of the IDMI-based pinning is that its scales as the spin-wave wave number. We incorporate these boundary conditions into an existing numerical model for the dynamics of the Damon-Eshbach spin wave in ferromagnetic films. IDMI affects the dispersion and the frequency non-reciprocity of the travelling Damon-Eshbach spin wave. For a broad range of film thicknesses L and wave numbers, the results of the numerical simulations of the spin wave dispersion are in a good agreement with a simple analytical expression, which shows that the contribution of IDMI to the dispersion scales as 1/L, similarly to the effect of other types of interfacial anisotropy. Suggestions to experimentalists how to detect the presence of IDMI in a spin wave experiment are given.

  19. Atmospheric Radiation Measurement (ARM) Data from the Eastern North Atlantic Site (ENA), Graciosa Island, Azores

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Wood, Robert

    From May 2009 through December 2010, the ARM Mobile Facility obtained data from a location near the airport on Graciosa Island to support the Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) field campaign. The campaign was led by principal investigator Robert Wood. Results from this campaign confirmed that the Azores have the ideal mix of conditions to study how clouds, aerosols, and precipitation interact. This new observation site will have significant enhancements to instruments previously deployed to the Azores, including a Ka-/W-band scanning cloud radar, precipitation radar, and Doppler lidar. It has the full support of the Azorean government and collaborators at the University of the Azores. Los Alamos National Laboratory will operate the site for the ARM Facility.

  20. Large Amplitude Spatial and Temporal Gradients in Atmospheric Boundary Layer CO2 Mole Fractions Detected With a Tower-Based Network in the U.S. Upper Midwest

    SciTech Connect (OSTI)

    Miles, Natasha; Richardson, S. J.; Davis, Kenneth J.; Lauvaux, Thomas; Andrews, A.; West, Tristram O.; Bandaru, Varaprasad; Crosson, Eric R.

    2012-02-21T23:59:59.000Z

    This study presents observations of atmospheric CO{sub 2} mole fraction from a nine-tower, regional network deployed during the North American Carbon Program's Mid-Continent Intensive during 2007-2009. Within this network in a largely agricultural area, mean atmospheric CO{sub 2} gradients were strongly correlated with both ground-based inventory data and estimates from satellite remote sensing. The average seasonal drawdown for corn-dominated sites (35 ppm) is significantly larger than has been observed at other continental boundary layer sites. Observed growing-season median CO{sub 2} gradients are strongly dependent on local flux. The gradients between cross-vegetation site-pairs, for example, average 2.0 ppm/100 km, four times larger than the similar-vegetation site-pair average. Daily-timescale gradients are as large as 5.5 ppm/100 km, but dominated by advection rather than local flux. Flooding in 2008 led to a region-wide 23 week delay in growing-season minima. The observations show that regional-scale CO{sub 2} mole fraction networks yield large, coherent signals governed largely by regional sources and sinks of CO{sub 2}.

  1. Boundary Layer Cloud Turbulence Characteristics

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced Materials Find FindRewindParticleBorn on anJeffersonBound

  2. Boundary streaming with Navier boundary condition Jin-Han Xiea)

    E-Print Network [OSTI]

    Vanneste, Jacques

    is the fluid's kinematic shear viscosity and is the wave's angular frequency. In water, and for frequencies applications involving high-frequency acoustic waves over a solid boundary, the Stokes boundary-layer thickness to travelling and standing waves shows that the boundary slip respectively increases and decreases the streaming

  3. 8, 88178846, 2008 Observed boundary-

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 8, 8817­8846, 2008 Observed boundary- layer/mesoscale impacts on Saharan dust J. H. Marsham et and Enviroment, University of Leeds, Leeds, UK 2 Institut f¨ur Meteorologie und Klimaforschung, Universit@env.leeds.ac.uk) 8817 #12;ACPD 8, 8817­8846, 2008 Observed boundary- layer/mesoscale impacts on Saharan dust J. H

  4. Oscillatory flow across an irregular boundary Geno Pawlak

    E-Print Network [OSTI]

    Pawlak, Geno

    ; KEYWORDS: eddies, tidal mixing, rough boundary, oscillatory flow, residual currents, wave boundary layers 1Oscillatory flow across an irregular boundary Geno Pawlak Department of Ocean and Resources. Introduction [2] Oscillatory flow past a rough boundary is a prevalent feature in a number of oceanographic

  5. Boundary layer response to wind gusts

    E-Print Network [OSTI]

    Morland, Bruce Thomas

    1968-01-01T23:59:59.000Z

    . and Mrs. Sruce T'. garland. Ths author took his gachslcr cf Science degree frns Arlington Stats College in lp66. He worked briefly fcr X, lug&secs~ought dircraft in ths airlcads group ior the p g Crusader. While working ca his Meeter ef Science degree...

  6. Convective Instability of a Boundary Layer with

    E-Print Network [OSTI]

    Conrad, Clint

    proportional to the integral over the depth of the lithosphere of the 19 #12;ratio of thermal buoyancy. Such instabilities are driven by the negative thermal buoyancy of the cold lithosphere and retarded largely for driving convective downwelling. For non-Newtonian viscosity with power law exponent n and temperature

  7. Stability of Small Viscosity Noncharacteristic Boundary Layers

    E-Print Network [OSTI]

    Métivier, Guy

    . . . . . . . . . . . . . . . . . . . 17 1.3.2 The mixed Cauchy-problem . . . . . . . . . . . . . . . 17 1.4 BKW expansions

  8. Stability of Small Viscosity Noncharacteristic Boundary Layers

    E-Print Network [OSTI]

    Métivier, Guy

    . . . . . . . . . . . . . . . . . . . 17 1.3.2 The mixed Cauchy­problem . . . . . . . . . . . . . . . 17 1.4 BKW expansions

  9. Thunderstorm influence on boundary layer winds

    E-Print Network [OSTI]

    Schmidt, Jill Marie

    1986-01-01T23:59:59.000Z

    of this research was to develop a conceptual model of selected pre-storm ambient conditions as a function of the strength of a thunderstorm's outflow. The time of maximum rainfall during the thunderstorm in relation to the time of maximum outflow was a... selected for study from well-defined Code 3 cells (thunderstorms). The results indicated that two conceptual models were necessary to describe the pre-storm ambient conditions that led to thunderstorm development and outflow. One model contained...

  10. Boundary Layer Lubrication Mechanisms | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: The FutureCommentsEnergyandapproximatelyBoostingand Capacity Concerns inStudy1

  11. Boundary Layer Lubrication Mechanisms | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: The FutureCommentsEnergyandapproximatelyBoostingand Capacity Concerns

  12. Boundary Layer Lubrication | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: The FutureCommentsEnergyandapproximatelyBoostingand Capacity

  13. Boundary Layer Lubrication | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: The FutureCommentsEnergyandapproximatelyBoostingand Capacity2009 DOE Hydrogen

  14. ARM - Field Campaign - Boundary Layer Cloud IOP

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032)8Li (59AJ76)ARM2,govCampaignsAircraftCloud

  15. ARM - Measurement - Planetary boundary layer height

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDCnarrowband upwelling irradiancenumber concentration

  16. MAE Seminar Series Boundary Closures for

    E-Print Network [OSTI]

    Krovi, Venkat

    ) boundary layer stability and transition. 206 Furnas Hall Thursday, April 8th, 2010 11:00 am ­ 12:00 pmMAE Seminar Series Boundary Closures for ESWENO Schemes Mark H. Carpenter, Ph.D. Computational AeroSciences Branch NASA Langley Research Center Abstract Energy Stable Weighted Essentially Non--Oscillatory (ESWENO

  17. atmospheric layers: Topics by E-print Network

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

    Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current...

  18. atmospheric superficial layer: Topics by E-print Network

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

    Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current...

  19. Finite element analysis of shells with layers

    E-Print Network [OSTI]

    Hiller, Jean-François, 1974-

    2002-01-01T23:59:59.000Z

    It is well established that thin shell structures frequently feature narrow bands of strain concentration and localized displacement irregularities referred to as boundary and internal layers. It is crucial to capture these ...

  20. PROPAGATION OF ALFVN WAVES AT THE PLASMA SHEET BOUNDARY Robert L. Lysak and Yan Song

    E-Print Network [OSTI]

    Lysak, Bob

    PROPAGATION OF ALFVÃ?N WAVES AT THE PLASMA SHEET BOUNDARY LAYER Robert L. Lysak and Yan Song School conversion or by localized plasma flows in the tail. The generation and propagation of these waves is studied nonlinear MHD simulations of wave propagation at the boundary layer. INTRODUCTION Recent observations from

  1. Momentum and heat fluxes in a turbulent air flow over a wet, smooth boundary

    E-Print Network [OSTI]

    Rice, Warren

    1958-01-01T23:59:59.000Z

    Idealized sketch, of boundary layer flow regions................ .............45 Figure 2 Schematic diagram of wind tunnel. . . . 46 Figure 3 Photograph of wind tunnel............ .. 47 Figure 4 Photograph of wind tunnel............ .. 47 Figure 5... mechanism and probe.................. .. 49 Figure 9 Distances of interest in the momentum and thermal boundary layers ............ 50 Figure 10 A typical velocity and temperature profile comparison .................. .. 51 Figure 1 1 Variation...

  2. Running Boundary Condition

    E-Print Network [OSTI]

    Satoshi Ohya; Makoto Sakamoto; Motoi Tachibana

    2013-01-28T23:59:59.000Z

    In this paper we argue that boundary condition may run with energy scale. As an illustrative example, we consider one-dimensional quantum mechanics for a spinless particle that freely propagates in the bulk yet interacts only at the origin. In this setting we find the renormalization group flow of U(2) family of boundary conditions exactly. We show that the well-known scale-independent subfamily of boundary conditions are realized as fixed points. We also discuss the duality between two distinct boundary conditions from the renormalization group point of view. Generalizations to conformal mechanics and quantum graph are also discussed.

  3. Jupiter's Great Red Spot and zonal winds as a self-consistent, one-layer, quasigeostrophic flow

    E-Print Network [OSTI]

    Marcus, Philip S.

    -value calculations in which the weather layer starts at rest produce oscillatory east-west winds. Like the Jovian stratified with respect to thermal convection. The layer's top boundary is the tropo- pause which acts boundary is the top of an underlying convective zone. Because the layer's stratification (Brunt

  4. Boundaries and Topological Algorithms

    E-Print Network [OSTI]

    Fleck, Margaret Morrison

    1988-09-01T23:59:59.000Z

    This thesis develops a model for the topological structure of situations. In this model, the topological structure of space is altered by the presence or absence of boundaries, such as those at the edges of objects. ...

  5. Intrusive gravity currents in two-layer

    E-Print Network [OSTI]

    Flynn, Morris R.

    Intrusive gravity currents in two-layer stratified media Morris R. Flynn & Paul F. Linden Dept.avalanche.org/pictures #12;· `Microbursts' pose a non-trivial threat to airplane safety Introduction Impacts on human health;· Whereas gravity currents travel along a solid boundary, intrusive gravity currents or intrusions propagate

  6. Numerical simulations of the stratified oceanic bottom boundary layer

    E-Print Network [OSTI]

    Taylor, John R.

    2008-01-01T23:59:59.000Z

    approximation that the mean wave energy and the backgroundfound that only 6% of the wave energy was re?ected back fromfound that the internal wave energy spec- trum in the outer

  7. Supersonic turbulent boundary layers with periodic mechanical non-equilibrium 

    E-Print Network [OSTI]

    Ekoto, Isaac Wesley

    2007-04-25T23:59:59.000Z

    questions have been raised. The fundamental questions this dissertation addressed are: (1) What are the effects of wall topology with sharp versus blunt leading edges? and (2) Is it possible that a further reduction of turbulent scales can occur if surface...

  8. EXPERIMENTAL STUDY OF COMBUSTION IN A TURBULENT BOUNDARY LAYER

    E-Print Network [OSTI]

    Cheng, R.K.

    2011-01-01T23:59:59.000Z

    States Section of the Combustion Institute, Stanford, CA,Cheng, R. K. , "Catalyzed Combustion of H2/ Air Mixtures inWorkshop on Catalytic Combustion, Asheville, North Carolina,

  9. A Note on the Intermediate Region in Turbulent Boundary Layers

    E-Print Network [OSTI]

    G. I. Barenblatt; A. J. Chorin; V. M. Prostokishin

    2000-02-16T23:59:59.000Z

    We demonstrate that the processing of the experimental data for the average velocity profiles obtained by J. M. \\"Osterlund (www.mesh.kth.se/$\\sim$jens/zpg/) presented in [1] was incorrect. Properly processed these data lead to the opposite conclusion: they confirm the Reynolds-number-dependent scaling law and disprove the conclusion that the flow in the intermediate (`overlap') region is Reynolds-number-independent.

  10. DIRECT SIMULATION OF SPATIALLY EVOLVING COMPRESSIBLE TURBULENT BOUNDARY LAYERS

    E-Print Network [OSTI]

    Erlebacher, Gordon

    of the cold wall condition used in Ref. 6, and, other differences. The computational method used in this study compressible flows because of the interest in designing high speed vehicles and the associated propulsion on temperature. Under the adiabatic conditions of the experiment, the temperature increases as the wall

  11. Control of the Transitional Boundary Layer Brandt A. Belson

    E-Print Network [OSTI]

    Rowley, Clarence W.

    in the presence of unmodeled disturbances. Next, we focus on a specific type of actuator, the single dielectric barrier discharge (SDBD) plasma actuator. An array of these plasma actuators is oriented to produce stream such that the controllers perform well when applied to the experiment. Lastly, we also simulate the plasma actuators

  12. THERMOPHORESIS OF PARTICLES IN A HEATED BOUNDARY LAYER

    E-Print Network [OSTI]

    Talbot, L.

    2012-01-01T23:59:59.000Z

    I (f) X Fig. 6 Reduced thermophoretic force as a function offrom the plate surface by thermophoretic forces. causing aseveral theories for the thermophoretic force. It was found

  13. absorbing boundary layers: Topics by E-print Network

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

    limits: (a) Pr>1, Pr1 and (b) Pr>>1. These two theoretical predictions are in excellent agreement with the results of our direct numerical simulations for Pr4.38 (water) and...

  14. IMPACT OF BOUNDARY-LAYER CUTTING ON FREE-SURFACE

    E-Print Network [OSTI]

    California at San Diego, University of

    height ~ 1 m · Overall height ~ 5.5 m E Flow conditionerE Flow conditioner F NozzleF Nozzle G Liquid

  15. ORIGINAL PAPER Mechanical filtering by the boundary layer and fluidstructure

    E-Print Network [OSTI]

    McHenry, Matt

    force coefficient for fluid c speed of sound in water C integration constant Em Young's modulus of cupular matrix F stimulus frequency Fb buoyant force Fe elastic force Fm inertial force Fa acceleration

  16. The effect of tangential blowing on boundary-layer profiles

    E-Print Network [OSTI]

    Olson, Milford Eugene

    1967-01-01T23:59:59.000Z

    downstream of the slot. The width of the slot was set at 0. 013, 0. 033, and 0. 0415 inches. The blowing rates were varied to give a jet velocity of approximately 0, 163, 246, and 2 /5 feet per s cond. Results of the data are presented in graphical...; Blowing Rate Symbols B) B2 B 3 Cl C 2 C 3 D V (fps) J 163 246 2 75 163 246 275 163 Bjowing Rale (ft /sec) . 3 0. 0418 0. 0630 0. 0705 0. 1061 0. 1600 0. 1790 0. 1333 D D 3 246 275 0. 2013 0. 2250 A theory which expressed a...

  17. Experimental and theoretical study of turbulent oscillatory boundary layers

    E-Print Network [OSTI]

    Yuan, Jing, Ph. D. Massachusetts Institute of Technology

    2013-01-01T23:59:59.000Z

    Sediment transport is of crucial importance to engineering projects in coastal regions, so it is of primary interest in coastal engineering. The driving forces for sediment transport are mostly determined by the hydrodynamics ...

  18. Supersonic turbulent boundary layers with periodic mechanical non-equilibrium

    E-Print Network [OSTI]

    Ekoto, Isaac Wesley

    2007-04-25T23:59:59.000Z

    questions have been raised. The fundamental questions this dissertation addressed are: (1) What are the effects of wall topology with sharp versus blunt leading edges? and (2) Is it possible that a further reduction of turbulent scales can occur if surface...

  19. Thermal boundary layer development in dispersed flow film boiling

    E-Print Network [OSTI]

    Hull, Lawrence M.

    1982-01-01T23:59:59.000Z

    Dispersed flow film boiling consists of a dispersion of droplets which are carried over a very hot surface by their vapor. This process occurs in cryogenic equipment and wet steam turbines. It is also of interest in the ...

  20. Linear Stability Analysis of a Boundary Layer with Plasma Actuators

    E-Print Network [OSTI]

    Roy, Subrata

    in the ith direction p Pressure ¯ui Mean flow velocity in the ith direction ¯p Mean pressure ~ui Disturbance flow velocity in the ith direction ~p Disturbance pressure ui Complex 1D disturbance flow velocity Complex spatial frequency in x1 Complex spatial frequency in x3 Complex temporal frequency cp Complex

  1. DIFFUSION OF A CHEMICAL SPECIES THROUGH A VISCOUS BOUNDARY LAYER

    E-Print Network [OSTI]

    Keller, J.

    2011-01-01T23:59:59.000Z

    2.3 Evaluation of a Coal Gasification Atmosphere. . -iv-a highly cor- rosive coal gasification mixture. It is shown2.3 Evaluation of a Coal Gasification Atmosphere The purpose

  2. Boundary layer ingesting inlet design for a silent aircraft

    E-Print Network [OSTI]

    Freuler, Patrick N., 1980-

    2005-01-01T23:59:59.000Z

    (cont.) common nacelle, L/D ratios between 2.5 and 3.0, fan face to throat area ratios above 1.06, and offsets lower than 11%. Curvature ahead of the inlet should be avoided as well as bifurcations inside the duct. Inlet ...

  3. Interaction between surface and atmosphere in a convective boundary layer /

    E-Print Network [OSTI]

    Garai, Anirban

    2013-01-01T23:59:59.000Z

    resulting in constant wind, and potential temperature andatmospheric wind speed, direction and potential temperatureatmospheric profiles (wind speed, potential temperature),

  4. Large-Scale Streamwise Turbulent Structures in Hypersonic Boundary Layers

    E-Print Network [OSTI]

    English, Benjamin L.

    2013-04-22T23:59:59.000Z

    13 Before and after example of pre-processed images........................... 27 14 Average velocity and TKE comparison ............................................ 37 15 Reynolds shear stress comparison... 19 Instantaneous velocity field comparison at ? ..................... 42 20 Instantaneous velocity field comparison at ? ..................... 44 21 Instantaneous velocity field comparison at ? ..................... 45...

  5. OFFSHORE BOUNDARY-LAYER MODELLING H. Bergstrm1

    E-Print Network [OSTI]

    currently be incorporated into a wind farm design tool. The offshore thermal stratification climate is also investigated. 1 INTRODUCTION Mapping the offshore wind climate, it is important to take into account both land contribute to a complex wind field, and affect the wind also at large offshore distances. Spatial variations

  6. ARM - Field Campaign - 2013 Lower Atmospheric Boundary Layer Experiment

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032)8Li (59AJ76)ARM2, 2006 [FacilityMission Under52 NEAQS (New7

  7. ARM - Field Campaign - Lower Atmospheric Boundary Layer Experiment

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa

  8. Vertical Velocities in Continental Boundary Layer Stratocumulus Clouds

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsing Maps1 - USAFof EnergyVendorwinsVenue andVertical

  9. ARM - PI Product - Planetary Boundary Layer from AERI and MPL

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDCnarrowbandheatProductsISDAC

  10. A dual mass flux framework for boundary layer convection

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032) -Less isNFebruaryOctober 2,generation high-performanceA dual mass

  11. Spectrum of local boundary operators from boundary form factor bootstrap

    E-Print Network [OSTI]

    M. Szots; G. Takacs

    2007-03-26T23:59:59.000Z

    Using the recently introduced boundary form factor bootstrap equations, we map the complete space of their solutions for the boundary version of the scaling Lee-Yang model and sinh-Gordon theory. We show that the complete space of solutions, graded by the ultraviolet behaviour of the form factors can be brought into correspondence with the spectrum of local boundary operators expected from boundary conformal field theory, which is a major evidence for the correctness of the boundary form factor bootstrap framework.

  12. Transgressing the Boundaries: An Afterword

    E-Print Network [OSTI]

    Sokal, Alan

    the Boundaries: Toward a Transformative Hermeneutics of Quantum Gravity'', which appeared in Social Text #46

  13. Wavelet analysis study of microbubble drag reduction in a boundary channel flow 

    E-Print Network [OSTI]

    Zhen, Ling

    2006-04-12T23:59:59.000Z

    Particle Image Velocimetry (PIV) and pressure measurement techniques were performed to investigate the drag reduction due to microbubble injection in the boundary layer of a fully developed turbulent channel flow. ...

  14. Preprint of the paper "A General Formulation based on the Boundary Element Method for the Analysis

    E-Print Network [OSTI]

    Colominas, Ignasi

    cost) to the analysis of large grounding systems in electrical substations. In this paper we present a new Boundary Element formulation for substation grounding systems embedded in layered soils of the substation site. Obviously, from a technical (and

  15. Friction and Diapycnal Mixing at a Slope: Boundary Control of Potential Vorticity

    E-Print Network [OSTI]

    Benthuysen, Jessica

    Although atmospheric forcing by wind stress or buoyancy flux is known to change the ocean’s potential vorticity (PV) at the surface, less is understood about PV modification in the bottom boundary layer. The adjustment of ...

  16. Interface dynamics for layered structures

    E-Print Network [OSTI]

    Takao Ohta; David Jasnow

    1997-07-17T23:59:59.000Z

    We investigate dynamics of large scale and slow deformations of layered structures. Starting from the respective model equations for a non-conserved system, a conserved system and a binary fluid, we derive the interface equations which are a coupled set of equations for deformations of the boundaries of each domain. A further reduction of the degrees of freedom is possible for a non-conserved system such that internal motion of each domain is adiabatically eliminated. The resulting equation of motion contains only the displacement of the center of gravity of domains, which is equivalent to the phase variable of a periodic structure. Thus our formulation automatically includes the phase dynamics of layered structures. In a conserved system and a binary fluid, however, the internal motion of domains turns out to be a slow variable in the long wavelength limit because of concentration conservation. Therefore a reduced description only involving the phase variable is not generally justified.

  17. Boundary Plasma Turbulence Simulations for Tokamaks

    SciTech Connect (OSTI)

    Xu, X; Umansky, M; Dudson, B; Snyder, P

    2008-05-15T23:59:59.000Z

    The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.

  18. Condition Number Estimates for Combined Potential Boundary Integral

    E-Print Network [OSTI]

    Langdon, Stephen

    Condition Number Estimates for Combined Potential Boundary Integral Operators in Acoustic parameter. Of independent interest we also obtain upper and lower bounds on the norms of two oscillatory integral operators, namely the classical acoustic single- and double-layer potential operators. 1

  19. Condition Number Estimates for Combined Potential Boundary Integral

    E-Print Network [OSTI]

    Langdon, Stephen

    Condition Number Estimates for Combined Potential Boundary Integral Operators in Acoustic parameter. Of independent interest we first obtain upper and lower bounds on the norms of two oscillatory integral operators, namely the classical acoustic single- and double-layer potential operators. 1

  20. Gas-surface interaction and boundary conditions for the Boltzmann equation

    E-Print Network [OSTI]

    Mieussens, Luc

    Gas-surface interaction and boundary conditions for the Boltzmann equation St´ephane Brull, Pierre Equation. The interaction between the wall atoms and the gas molecules within a thin surface layer of the gas in the bulk flow. Boundary conditions are formally derived from this model by using classical

  1. Boundary transfer matrices and boundary quantum KZ equations

    E-Print Network [OSTI]

    Bart Vlaar

    2014-10-31T23:59:59.000Z

    A simple relation between inhomogeneous transfer matrices and boundary quantum KZ equations is exhibited for quantum integrable systems with reflecting boundary conditions, analogous to an observation by Gaudin for periodic systems. Thus the boundary quantum KZ equations receive a new motivation. We also derive the commutativity of Sklyanin's boundary transfer matrices by merely imposing appropriate reflection equations, i.e. without using the conditions of crossing symmetry and unitarity of the R-matrix.

  2. A new twist on Stokes' second problem: Partial penetration of nonlinearity in sheared viscoelastic layers

    E-Print Network [OSTI]

    Forest, M. Gregory

    viscoelastic layer to an oscillating boundary, greater than the gap-loading limit of typical shear rheometers oscillatory shear driving con- ditions on the mucus layer. Very little evidence is available on the details extend our previous studies [3­5] of viscoelas- tic layers under oscillatory driving conditions

  3. A fast multipole boundary element method for 3D multi-domain acoustic scattering problems based on the BurtonMiller formulation

    E-Print Network [OSTI]

    Liu, Yijun

    A fast multipole boundary element method for 3D multi-domain acoustic scattering problems based: Received 9 August 2011 Accepted 30 November 2011 Keywords: Boundary element method Fast multipole method Acoustics Multi-domain Multi-layered Effective moment computations a b s t r a c t A fast multipole boundary

  4. Photovoltaic devices comprising zinc stannate buffer layer and method for making

    DOE Patents [OSTI]

    Wu, Xuanzhi (Golden, CO); Sheldon, Peter (Lakewood, CO); Coutts, Timothy J. (Lakewood, CO)

    2001-01-01T23:59:59.000Z

    A photovoltaic device has a buffer layer zinc stannate Zn.sub.2 SnO.sub.4 disposed between the semiconductor junction structure and the transparent conducting oxide (TCO) layer to prevent formation of localized junctions with the TCO through a thin window semiconductor layer, to prevent shunting through etched grain boundaries of semiconductors, and to relieve stresses and improve adhesion between these layers.

  5. Geometry of Weak Stability Boundaries

    E-Print Network [OSTI]

    Edward Belbruno; Marian Gidea; Francesco Topputo

    2012-04-06T23:59:59.000Z

    The notion of a weak stability boundary has been successfully used to design low energy trajectories from the Earth to the Moon. The structure of this boundary has been investigated in a number of studies, where partial results have been obtained. We propose a generalization of the weak stability boundary. We prove analytically that, in the context of the planar circular restricted three-body problem, under certain conditions on the mass ratio of the primaries and on the energy, the weak stability boundary about the heavier primary coincides with a branch of the global stable manifold of the Lyapunov orbit about one of the Lagrange points.

  6. A simplex model for layered niche networks

    E-Print Network [OSTI]

    P. Fraundorf

    2007-03-06T23:59:59.000Z

    The standing crop of correlations in metazoan communities may be assessed by an inventory of niche structures focused inward and outward from the physical boundaries of skin (self), gene-pool (family), and meme-pool (culture). We consider tracking the progression from three and four correlation layers in many animal communities, to five of six layers for the shared adaptation of most humans, with an attention-slice model that maps the niche-layer focus of individuals onto the 6-variable space of a 5-simplex. The measure puts questions about the effect, on culture and species, of policy and natural events into a common context, and may help explore the impact of electronically-mediated codes on community health.

  7. Cell boundary fault detection system

    DOE Patents [OSTI]

    Archer, Charles Jens (Rochester, MN); Pinnow, Kurt Walter (Rochester, MN); Ratterman, Joseph D. (Rochester, MN); Smith, Brian Edward (Rochester, MN)

    2011-04-19T23:59:59.000Z

    An apparatus and program product determine a nodal fault along the boundary, or face, of a computing cell. Nodes on adjacent cell boundaries communicate with each other, and the communications are analyzed to determine if a node or connection is faulty.

  8. Recursion Relation for Boundary Contribution

    E-Print Network [OSTI]

    Qingjun Jin; Bo Feng

    2015-05-01T23:59:59.000Z

    It is well known that under a BCFW-deformation, there is a boundary contribution when the amplitude scales as O(1) or worse. We show that boundary contributions have a similar recursion relation as scattering amplitude. Just like the BCFW recursion relation, where scattering amplitudes are expressed as the products of two on-shell sub-amplitudes (plus possible boundary contributions), our new recursion relation expresses boundary contributions as products of sub-amplitudes and boundary contributions with less legs, plus yet another possible boundary contribution. In other words, the complete scattering amplitude, including boundary contributions, can be obtained by multiple steps of recursions, unless the boundary contributions are still non-zero when all possible deformations are exploited. We demonstrate this algorithm by several examples. Especially, we show that for standard model like renormalizable theory in 4D, i.e., the theory including only gauge boson, fermions and scalars, the complete amplitude can always be computed by at most four recursive steps using our algorithm.

  9. Photonic layered media

    DOE Patents [OSTI]

    Fleming, James G. (Albuquerque, NM); Lin, Shawn-Yu (Albuquerque, NM)

    2002-01-01T23:59:59.000Z

    A new class of structured dielectric media which exhibit significant photonic bandstructure has been invented. The new structures, called photonic layered media, are easy to fabricate using existing layer-by-layer growth techniques, and offer the ability to significantly extend our practical ability to tailor the properties of such optical materials.

  10. Turbulence structure of the surface layer Boun 2247-03D TURBULENCE STRUCTURE OF THE UNSTABLE ATMOSPHERIC

    E-Print Network [OSTI]

    Moncrieff, John B.

    to the creation of emerging TEAL structures to the power passing down the Richardson cascade in the outer layer-Obukhov similarity, self-organizing systems 1. Introduction In convective boundary layers the structureTurbulence structure of the surface layer Boun 2247-03D TURBULENCE STRUCTURE OF THE UNSTABLE

  11. Formation of a sandy near-bed transport layer from a fine-grained bed under oscillatory flow

    E-Print Network [OSTI]

    Formation of a sandy near-bed transport layer from a fine-grained bed under oscillatory flow to be an important effect for the formation of ripples and the dynamics of the boundary layer above a predominantly), Formation of a sandy near-bed transport layer from a fine-grained bed under oscillatory flow, J. Geophys

  12. Vacuum Structure and Boundary Renormalization Group

    E-Print Network [OSTI]

    M. Asorey; J. M. Munoz-Castaneda

    2007-12-28T23:59:59.000Z

    The vacuum structure is probed by boundary conditions. The behaviour of thermodynamical quantities like free energy, boundary entropy and entanglement entropy under the boundary renormalization group flow are analysed in 2D conformal field theories. The results show that whereas vacuum energy and boundary entropy turn out to be very sensitive to boundary conditions, the vacuum entanglement entropy is independent of boundary properties when the boundary of the entanglement domain does not overlap the boundary of the physical space. In all cases the second law of thermodynamics holds along the boundary renormalization group flow.

  13. ON THE ACOUSTIC SINGLE LAYER POTENTIAL: STABILIZATION AND FOURIER ANALYSIS

    E-Print Network [OSTI]

    Buffa, Annalisa

    ON THE ACOUSTIC SINGLE LAYER POTENTIAL: STABILIZATION AND FOURIER ANALYSIS A. BUFFA AND S. SAUTER in the stability and convergence estimates attains its minumum. Key words. Acoustic scattering, Galerkin boundary discretizations for the Helmholtz problem suffer from the pollution effect, i.e., the constants in the Galerkin

  14. Electric Field in a Double Layer and the Imparted Momentum

    SciTech Connect (OSTI)

    Fruchtman, A. [Holon Academic Institute of Technology, 52 Golomb Street, Holon 58102 (Israel)

    2006-02-17T23:59:59.000Z

    It is shown that the net momentum delivered by the large electric field inside a one-dimensional double layer is zero. This is demonstrated through an analysis of the momentum balance in the double layer at the boundary between the ionosphere and the aurora cavity. For the recently observed double layer in a current-free plasma expanding along a divergent magnetic field, an analysis of the evolution of the radially averaged variables shows that the increase of plasma thrust results from the magnetic-field pressure balancing the plasma pressure in the direction of acceleration, rather than from electrostatic pressure.

  15. Layered plasma polymer composite membranes

    DOE Patents [OSTI]

    Babcock, W.C.

    1994-10-11T23:59:59.000Z

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is [>=]2 and is the number of selective layers. 2 figs.

  16. Boundary Waters Canoe Area (Minnesota)

    Broader source: Energy.gov [DOE]

    The Boundary Waters Canoe Area occupies a large section of northern Minnesota, and is preserved as a primitive wilderness area. Construction and new development is prohibited. A map of the...

  17. NOTES AND CORRESPONDENCE An Analytic Longwave Radiation Formula for Liquid Layer Clouds

    E-Print Network [OSTI]

    NOTES AND CORRESPONDENCE An Analytic Longwave Radiation Formula for Liquid Layer Clouds VINCENT E of boundary layer clouds have used a convenient but idealized longwave radiation formula for clouds in their large-eddy simulations (LESs). Under what conditions is this formula justified? Can it be extended

  18. Cross-Layer Attack and Defense in Cognitive Radio Networks Wenkai Wang and Yan (Lindsay) Sun

    E-Print Network [OSTI]

    Sun, Yan Lindsay

    Cross-Layer Attack and Defense in Cognitive Radio Networks Wenkai Wang and Yan (Lindsay) Sun ECE research on security issues in cognitive radio networks mainly focuses on attack and defense in individual network layers. However, the attackers do not necessarily restrict themselves within the boundaries

  19. The viscosity structure of the D00 layer of the Earth's mantle inferred

    E-Print Network [OSTI]

    The viscosity structure of the D00 layer of the Earth's mantle inferred from the analysis layer Core­mantle boundary Viscosity Maxwell body a b s t r a c t The viscosity structure of the D00-diurnal to 18.6 years tidal deformations combined with model viscosity­depth profiles corresponding to a range

  20. Changing the Structure Boundary Geometry

    SciTech Connect (OSTI)

    Karasev, Viktor; Dzlieva, Elena; Ivanov, Artyom [St.-Petersburg State University, Physics Faculty, Ulianovskaya 1, Peterhof, St. Petersburg, 198504 (Russian Federation)

    2008-09-07T23:59:59.000Z

    Analysis of previously obtained results shows that hexagonal crystal lattice is the dominant type of ordering, in particular, in striated glow discharges. We explore the possibility for changing the dust distribution in horizontal cross sections of relatively highly ordered structures in a glow-discharge. Presuming that boundary geometry can affect dust distribution, we used cylindrical coolers held at 0 deg. C and placed against a striation containing a structure, to change the geometry of its outer boundary. By varying the number of coolers, their positions, and their separations from the tube wall, azimuthally asymmetric thermophoretic forces can be used to form polygonal boundaries and vary the angles between their segments (in a horizontal cross section). The corner in the structure's boundary of 60 deg. stimulates formation of hexagonal cells. The structure between the supported parallel boundaries is also characterized by stable hexagonal ordering. We found that a single linear boundary segment does not give rise to any sizable domain, but generates a lattice extending from the boundary (without edge defects). A square lattice can be formed by setting the angle equal to 90 deg. . However, angles of 45 deg. and 135 deg. turned out easier to form. Square lattice was created by forming a near-135 deg. corner with four coolers. It was noted that no grain ordering is observed in the region adjacent to corners of angles smaller than 30 deg. , which do not promote ordering into cells of any shape. Thus, manipulation of a structure boundary can be used to change dust distribution, create structures free of the ubiquitous edge defects that destroy orientation order, and probably change the crystal lattice type.

  1. Strain tensors in layer systems by precision ion channeling measurements

    SciTech Connect (OSTI)

    Trinkaus, H.; Buca, D.; Hollaender, B.; Minamisawa, R. A.; Mantl, S. [Institute of Bio- and Nanosystems (IBN 1) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Juelich, D-52425 Juelich (Germany); Hartmann, J. M. [CEA-LETI, MINATEC, 17 Rue des Martyrs, F-38054 Grenoble, Cedex 9 (France)

    2010-06-15T23:59:59.000Z

    A powerful method for analyzing general strain states in layer systems is the measurement of changes in the ion channeling directions. We present a systematic derivation and compilation of the required relations between the strain induced angle changes and the components of the strain tensor for general crystalline layer systems of reduced symmetry compared to the basic (cubic) crystal. It is shown that, for the evaluation of channeling measurements, virtually all layers of interest may be described as being 'pseudo-orthorhombic'. The commonly assumed boundary conditions and the effects of surface misorientations on them are discussed. Asymmetric strain relaxation in layers of reduced symmetry is attributed to a restriction in the slip system of the dislocations inducing it. The results are applied to {l_brace}110{r_brace}SiGe/Si layer systems.

  2. Layered Cathode Materials

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

    Layered Cathode Materials presented by Michael Thackeray Chemical Sciences and Engineering Division, Argonne Annual Merit Review DOE Vehicle Technologies Program Washington, D.C....

  3. A bridging technique to analyze the influence of boundary conditions on instability patterns

    SciTech Connect (OSTI)

    Hu Heng, E-mail: huheng@whu.edu.c [School of Civil Engineering, Wuhan University, 8 South Road of East Lake, 430072 Wuhan (China); Damil, Noureddine, E-mail: noureddine.damil@gmail.co [Laboratoire de Calcul Scientifique en Mecanique, Faculte des Sciences Ben M'Sik, Universite Hassan II Mohammedia-Casablanca, Sidi Othman, Casablanca (Morocco); Potier-Ferry, Michel, E-mail: michel.potierferry@univ-metz.f [Laboratoire d'Etude des Microstructures et de Mecanique des Materiaux, LEM3, UMR CNRS 7239, Universite Paul Verlaine-Metz, Ile du Saulcy, 57045 Metz Cedex 01 (France)

    2011-05-10T23:59:59.000Z

    In this paper, we present a new numerical technique that permits to analyse the effect of boundary conditions on the appearance of instability patterns. Envelope equations of Landau-Ginzburg type are classically used to predict pattern formation, but it is not easy to associate boundary conditions for these macroscopic models. Indeed, envelope equations ignore boundary layers that can be important, for instance in cases where the instability starts first near the boundary. In this work, the full model is considered close to the boundary, an envelope equation in the core and they are bridged by the Arlequin method . Simulation results are presented for the problem of buckling of long beams lying on a non-linear elastic foundation.

  4. Layering as Optimization Decomposition 3-1 Layering as OptimizationLayering as Optimization

    E-Print Network [OSTI]

    Fan, Xingzhe

    1 Layering as Optimization Decomposition 3-1 Layering as OptimizationLayering as Optimization DecompositionDecomposition Layering as Optimization Decomposition 3-2 CONTENTSCONTENTS Introduction (Marta;2 Layering as Optimization Decomposition 3-3 Layering as Optimization Decomposition Introduction By Marta

  5. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, Terry W. (Tracy, CA)

    1994-01-01T23:59:59.000Z

    A multiple density layered insulator for use with a laser is disclosed wh provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation.

  6. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, T.W.

    1994-09-06T23:59:59.000Z

    A multiple density layered insulator for use with a laser is disclosed which provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation. 4 figs.

  7. Multiple layer insulation cover

    DOE Patents [OSTI]

    Farrell, James J. (Livingston Manor, NY); Donohoe, Anthony J. (Ovid, NY)

    1981-11-03T23:59:59.000Z

    A multiple layer insulation cover for preventing heat loss in, for example, a greenhouse, is disclosed. The cover is comprised of spaced layers of thin foil covered fabric separated from each other by air spaces. The spacing is accomplished by the inflation of spaced air bladders which are integrally formed in the cover and to which the layers of the cover are secured. The bladders are inflated after the cover has been deployed in its intended use to separate the layers of the foil material. The sizes of the material layers are selected to compensate for sagging across the width of the cover so that the desired spacing is uniformly maintained when the cover has been deployed. The bladders are deflated as the cover is stored thereby expediting the storage process and reducing the amount of storage space required.

  8. Title: Ontario Greenbelt Boundary File Data Creator /

    E-Print Network [OSTI]

    Greenbelt Act 2005. Data contains three shapefiles: Greenbelt Designated Areas, Outer Boundary and River

  9. Computer Modeling of Transport of Oxidizing Species in Grain Boundaries during Zirconium Corrosion

    SciTech Connect (OSTI)

    Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks

    2014-06-01T23:59:59.000Z

    Zirconium (Zr) based alloys are widely used as the cladding materials in light-water reactors. The water-side corrosion of these alloys degrades their structural integrity and poses serious safety concerns. During the Zr corrosion process, a thin Zr oxide (ZrO2) layer forms on the alloy surface and serves as a barrier layer for further corrosion. The majority of the oxide has the monoclinic phase. At the transition region between the oxide and the metal, the oxide contains a thin layer of stabilized tetragonal phase. It is found that the texture of the tetragonal layer determines the protectiveness of the oxide for corrosion. The transport of oxidizing species, such as anion defects, cation defects, and electron through the tetragonal oxide layer could be the rate limiting step of the corrosion. The defect diffusion can be affected by the growing stresses and microstructures such as grain boundaries and dislocations. In this work molecular dynamics simulations are used to investigate the anion and cation diffusion in bulk and at grain boundaries in tetragonal ZrO2. The results show that defect diffusion at grain boundaries is complex and the behavior strongly depends on the grain boundary type. For most of the grain boundaries studied the defect diffusion are much slower than in the bulk, implying that grain boundaries may not be fast defect transport paths during corrosion. The connection between the modeling results and published experimental work will also be discussed. This work is funded by the Laboratory Directed Research and Development (LDRD) program at Idaho National Laboratory.

  10. Measurements of grain boundary properties in nanocrystalline ceramics

    SciTech Connect (OSTI)

    Chiang, Y.M.; Smyth, I.P.; Terwilliger, C.D. (Massachusetts Inst. of Tech., Cambridge, MA (USA). Dept. of Materials Science and Engineering); Petuskey, W.T. (Arizona State Univ., Tempe, AZ (USA). Dept. of Chemistry); Eastman, J.A. (Argonne National Lab., IL (USA))

    1990-11-01T23:59:59.000Z

    The advent of nanocrystalline ceramics prepared by a variety of solution-chemical and vapor deposition methods offers a unique opportunity for the determination grain boundary properties by bulk'' thermodynamic methods. In this paper we discuss results from two types of measurements on model nanocrystalline ceramics. The first is a solution thermodynamic measurement of the activity of nanocrystalline SiC in polycarbosilane-derived silicon carbide fibers (Nicalon). Structural studies have shown that Nicalon consists of well-ordered cubic ({beta} or 3C polytype) SiC grains separated by a very thin grain boundary layer (<1 nm thick) containing the oxygen. The physical properties and chemical reactivity of these fibers are distinctly different from that of bulk silicon carbide. Direct measurement of the alloy composition and analysis of the microstructure has allowed the dissolution reaction to be identified and a lower limit for the SiC activity in the nanocrystalline form to be determined. A second method of measuring grain boundary properties we have investigated for nanocrystalline Si and TiO{sub 2} is high temperature calorimetry. In appropriate samples the grain boundary enthalpy can be measured through the heat evolved during grain growth. Preliminary results on nanocrystalline Si prepared by the recrystallization of amorphous evaporated films and on TiO{sub 2} condensed from the vapor phase are discussed. 29 refs., 3 figs., 1 tab.

  11. Are nanophase grain boundaries anomalous?

    SciTech Connect (OSTI)

    Stern, E.A.; Siegel, R.W.; Newville, M.; Sanders, P.G.; Haskel, D. [Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States)] [Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States); [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); [Materials Science and Engineering Department, Northwestern University, Evanston, Illinois 60208 (United States)

    1995-11-20T23:59:59.000Z

    The grain boundary regions of nanophase Cu metal are investigated using the x-ray absorption fine structure (XAFS) technique. Typical samples made by standard techniques need to be greatly thinned if measured in transmission in order to eliminate experimental artifacts which erroneously lower the apparent coordination number. To avoid this problem the samples were measured by the total electron yield technique. The results indicate a grain boundary structure which, on the average, is similar to that in conventional polycrystalline Cu, contrary to previous XAFS measurements made in transmission which indicated a lower coordination number. {copyright} {ital 1995} {ital The} {ital American} {ital Physical} {ital Society}.

  12. Compliant layer chucking surface

    DOE Patents [OSTI]

    Blaedel, Kenneth L. (Dublin, CA); Spence, Paul A. (Pleasanton, CA); Thompson, Samuel L. (Pleasanton, CA)

    2004-12-28T23:59:59.000Z

    A method and apparatus are described wherein a thin layer of complaint material is deposited on the surface of a chuck to mitigate the deformation that an entrapped particle might cause in the part, such as a mask or a wafer, that is clamped to the chuck. The harder particle will embed into the softer layer as the clamping pressure is applied. The material composing the thin layer could be a metal or a polymer for vacuum or electrostatic chucks. It may be deposited in various patterns to affect an interrupted surface, such as that of a "pin" chuck, thereby reducing the probability of entrapping a particle.

  13. Thermal convection in a spherical shell with melting/freezing at either or both of its boundaries

    E-Print Network [OSTI]

    Deguen, Renaud

    2013-01-01T23:59:59.000Z

    In a number of geophysical or planetological settings (Earth's inner core, a silicate mantle crystallizing from a magma ocean, or an ice shell surrounding a deep water ocean) a convecting crystalline layer is in contact with a layer of its melt. Allowing for melting/freezing at one or both of the boundaries of the solid layer is likely to affect the pattern of convection in the layer. We study here the onset of thermal convection in a viscous spherical shell with dynamically induced melting/freezing at either or both of its boundaries. It is shown that the behavior of each interface depends on the value of a dimensional number P, which is the ratio of a melting/freezing timescale over a viscous relaxation timescale. A small value of P corresponds to permeable boundary conditions, while a large value of P corresponds to impermeable boundary conditions. The linear stability analysis predicts a significant effect of semi-permeable boundaries when the number P characterizing either of the boundary is small enough...

  14. Boundary Behavior of the GinzburgLandau Order Parameter in the Surface Superconductivity Regime

    E-Print Network [OSTI]

    Recanati, Catherine

    Boundary Behavior of the Ginzburg­Landau Order Parameter in the Surface Superconductivity Regime M­Landau theory for a type­II superconductor in an applied magnetic field varying between the second and third of this energy expansion, which allows us to prove the desired uniformity of the surface superconductivity layer

  15. Layered Spinach Salad Ingredients

    E-Print Network [OSTI]

    Liskiewicz, Maciej

    cucumbers 2 tomatoes 1/2 cup low-fat mayonnaise 1/2 cup parmesan cheese, grated 1/4 cup milk 1 1/2 teaspoons size pieces, layer on bottom of a large bowl. 2. Rinse mushrooms off under cool water and use a soft half. Layer on top of vegetables. 6. To make salad dressing, add mayonnaise, cheese, milk, dill weed

  16. Structured luminescence conversion layer

    DOE Patents [OSTI]

    Berben, Dirk; Antoniadis, Homer; Jermann, Frank; Krummacher, Benjamin Claus; Von Malm, Norwin; Zachau, Martin

    2012-12-11T23:59:59.000Z

    An apparatus device such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer deposited on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains regions such as color-changing and non-color-changing regions with particular shapes arranged in a particular pattern.

  17. 2. System boundaries; Balance equations

    E-Print Network [OSTI]

    Zevenhoven, Ron

    Example: an electric hot water heater in a house ­ The electric heater is a closed system ­ The water with the surroundings for example: combustion engines, pumps, distillation columns, living organisms Picture: SEHB06 #12;5/28 Systems and boundaries /3 An isolated system is a special kind of closed system Pictures: KJ05 Q = heat W

  18. Lagrangian Variational Framework for Boundary Value Problems

    E-Print Network [OSTI]

    Alexander Figotin; Guillermo Reyes

    2014-07-29T23:59:59.000Z

    A boundary value problem is commonly associated with constraints imposed on a system at its boundary. We advance here an alternative point of view treating the system as interacting "boundary" and "interior" subsystems. This view is implemented through a Lagrangian framework that allows to account for (i) a variety of forces including dissipative acting at the boundary; (ii) a multitude of features of interactions between the boundary and the interior fields when the boundary fields may differ from the boundary limit of the interior fields; (iii) detailed pictures of the energy distribution and its flow; (iv) linear and nonlinear effects. We provide a number of elucidating examples of the structured boundary and its interactions with the system interior. We also show that the proposed approach covers the well known boundary value problems.

  19. Irradiation Assisted Grain Boundary Segregation in Steels

    SciTech Connect (OSTI)

    Lu, Zheng; Faulkner, Roy G. [IPTME, Loughborough University, Loughborough, Leics (United Kingdom)

    2008-07-01T23:59:59.000Z

    The understanding of radiation-induced grain boundary segregation (RIS) has considerably improved over the past decade. New models have been introduced and much effort has been devoted to obtaining comprehensive information on segregation from the literature. Analytical techniques have also improved so that chemical analysis of layers 1 nm thick is almost routine. This invited paper will review the major methods used currently for RIS prediction: namely, Rate Theory, Inverse Kirkendall, and Solute Drag approaches. A summary is made of the available data on phosphorus RIS in reactor pressure vessel (RPV) steels. This will be discussed in the light of the predictions of the various models in an effort to show which models are the most reliable and easy to use for forecasting P segregation behaviour in steels. A consequence of RIS in RPV steels is a radiation induced shift in the ductile to brittle transition temperature (DBTT). It will be shown how it is possible to relate radiation-induced P segregation levels to DBTT shift. Examples of this exercise will be given for RPV steels and for ferritic steels being considered for first wall fusion applications. Cr RIS in high alloy stainless steels and associated irradiation-assisted stress corrosion cracking (IASCC) will be briefly discussed. (authors)

  20. Boundary Integral Equations and the Method of Boundary Elements

    E-Print Network [OSTI]

    Tsynkov, Semyon V.

    to consider the interior and exterior Dirichlet and Neumann boundary value problems for the Laplace equation: u 2u x2 1 + 2u x2 2 + 2u x2 3 = 0. Let be a bounded domain of the three-dimensional space R3 and exterior Dirichlet problems, respectively, and problems (13.1b) and (13.1d) are the interior and exterior

  1. Beyond the no-slip boundary condition

    E-Print Network [OSTI]

    Brenner, Howard

    This paper offers a simple macroscopic approach to the question of the slip boundary condition to be imposed upon the tangential component of the fluid velocity at a solid boundary. Plausible reasons are advanced for ...

  2. Revised Knudsen-layer reduction of fusion reactivity

    SciTech Connect (OSTI)

    Albright, B. J.; Molvig, Kim; Huang, C.-K.; Simakov, A. N.; Dodd, E. S.; Hoffman, N. M.; Kagan, G. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States); Schmit, P. F. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185-1186 (United States)] [Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185-1186 (United States)

    2013-12-15T23:59:59.000Z

    Recent work by Molvig et al. [Phys. Rev. Lett. 109, 095001 (2012)] examined how fusion reactivity may be reduced from losses of fast ions in finite assemblies of fuel. In this paper, this problem is revisited with the addition of an asymptotic boundary-layer treatment of ion kinetic losses. This boundary solution, reminiscent of the classical Milne problem from linear transport theory, obtains a free-streaming limit of fast ion losses near the boundary, where the diffusion approximation is invalid. Thermonuclear reaction rates have been obtained for the ion distribution functions predicted by this improved model. It is found that while Molvig's “Knudsen distribution function” bounds from above the magnitude of the reactivity reduction, this more accurate treatment leads to less dramatic losses of tail ions and associated reduction of thermonuclear reaction rates for finite fuel volumes.

  3. Immersed Boundary Methods for High-Resolution Simulation of Atmospheric Boundary-Layer Flow Over Complex Terrain

    E-Print Network [OSTI]

    Lundquist, Katherine Ann

    2010-01-01T23:59:59.000Z

    laminar flow over a ribbed channel. v ? U n F = + U · ?U + ?dimensional channel flow with smooth and ribbed surfaces. In

  4. SLE($?,?$)and Boundary Coulomb Gas

    E-Print Network [OSTI]

    S. Moghimi-Araghi; M. A. Rajabpour; S. Rouhani

    2005-08-07T23:59:59.000Z

    We consider the coulomb gas model on the upper half plane with different boundary conditions, namely Drichlet, Neuman and mixed. We related this model to SLE($\\kappa,\\rho$) theories. We derive a set of conditions connecting the total charge of the coulomb gas, the boundary charges, the parameters $\\kappa$ and $\\rho$. Also we study a free fermion theory in presence of a boundary and show with the same methods that it would lead to logarithmic boundary changing operators.

  5. Layered semiconductor neutron detectors

    DOE Patents [OSTI]

    Mao, Samuel S; Perry, Dale L

    2013-12-10T23:59:59.000Z

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  6. Title: Boundary File: GTA (Greater Toronto Area) Data Creator /

    E-Print Network [OSTI]

    Municipal Boundary shapefiles: Municipal Boundary ­ Upper Tier and District, and Municipal Boundary ­ Lower Municipality of Durham, Regional Municipality of York Data Type: Digital Vector Data Format: Shapefile Datum

  7. Impact of boundaries on velocity profiles in bubble rafts

    E-Print Network [OSTI]

    Yuhong Wang; Kapilanjan Krishan; Michael Dennin

    2006-01-31T23:59:59.000Z

    Under conditions of sufficiently slow flow, foams, colloids, granular matter, and various pastes have been observed to exhibit shear localization, i.e. regions of flow coexisting with regions of solid-like behavior. The details of such shear localization can vary depending on the system being studied. A number of the systems of interest are confined so as to be quasi-two dimensional, and an important issue in these systems is the role of the confining boundaries. For foams, three basic systems have been studied with very different boundary conditions: Hele-Shaw cells (bubbles confined between two solid plates); bubble rafts (a single layer of bubbles freely floating on a surface of water); and confined bubble rafts (bubbles confined between the surface of water below and a glass plate on top). Often, it is assumed that the impact of the boundaries is not significant in the ``quasi-static limit'', i.e. when externally imposed rates of strain are sufficiently smaller than internal kinematic relaxation times. In this paper, we directly test this assumption for rates of strain ranging from $10^{-3}$ to $10^{-2} {\\rm s^{-1}}$. This corresponds to the quoted quasi-static limit in a number of previous experiments. It is found that the top plate dramatically alters both the velocity profile and the distribution of nonlinear rearrangements, even at these slow rates of strain.

  8. Layer-by-layer assembly in confined geometries

    E-Print Network [OSTI]

    DeRocher, Jonathan P

    2011-01-01T23:59:59.000Z

    The fundamental nature of layer-by-layer (LbL) assembly in confined geometries was investigated for a number of different chemical systems. The first part of this thesis concerns the modification of microfluidic and ...

  9. Ion transport and structure of layer-by-layer assemblies

    E-Print Network [OSTI]

    Lutkenhaus, Jodie Lee

    2007-01-01T23:59:59.000Z

    Layer-by-layer (LbL) films of various architectures were examined as potential solid state electrolytes for electrochemical systems (e.g. batteries and fuel cells). The relationship between materials properties and ion ...

  10. Thermal Transitions in Layer-By-Layer Assemblies

    E-Print Network [OSTI]

    Sung, Choonghyun

    2014-10-13T23:59:59.000Z

    Thermal transitions in layer-by-layer (LbL) assemblies were investigated under dry and hydrated conditions. In the dry state, the effects of film thickness and the film deposition method on the glass transition temperature (Tg) were studied...

  11. Engineering electroresponsive layer-by-layer thin films

    E-Print Network [OSTI]

    Schmidt, Daniel J., Ph. D. Massachusetts Institute of Technology

    2011-01-01T23:59:59.000Z

    Electroresponsive layer-by-layer (LbL) polymer films and polymer nanocomposite films were investigated as model systems for electrically triggered drug delivery applications and "mechanomutable" surface coating applications. ...

  12. Gradient zone-boundary control in salt-gradient solar ponds

    DOE Patents [OSTI]

    Hull, J.R.

    1982-09-29T23:59:59.000Z

    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizeable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

  13. Shaping Environmental Justice: Applying Science, Technology, and Society Boundary Work

    E-Print Network [OSTI]

    Huang, Chih-Tung

    2012-01-01T23:59:59.000Z

    Applying Science, Technology and Society Boundary Work Chih-the STS (Science, Technology and Society) study as boundary-

  14. Experimental investigation of mixing in a stratified fluid due to diffusion-driven flows in a loosely-packed particle layer

    E-Print Network [OSTI]

    Etheridge, William B. (William Bruce)

    2007-01-01T23:59:59.000Z

    An experimental study was undertaken to investigate if a loosely-packed particle layer can induce mixing due to diffusion-driven Phillips-Wunsch boundary flows in a quiescent stratified fluid. Diffusion-driven flows can ...

  15. A mathematical model of corrosion of a conducting porous layer on a rotating disk electrode

    E-Print Network [OSTI]

    Ryan, William Edward

    1986-01-01T23:59:59.000Z

    . This approach, however, fails to account, for many of the complexities involved in actual corrosion such as pH effects upon passivation and reverse kinetics of oxygen reduction reaction. In a later study, Alkire and Siitari (21) characterized an ideal pitting.... Description of Porous Electrode B. Governing Equations? Solution Diffusion Layer C. Governing Equations? Porous Electrode Layer D. Butler-Volmer Kinetic Rate Equation E. Boundary Conditions F. Solution Technique 12 14 17 IV RESULTS AND DISCUSSION A...

  16. Analysis of leakage current in buried heterostructure lasers with semiinsulating blocking layers

    SciTech Connect (OSTI)

    Asada, S.; Sugou, S.; Kasahara, K.; Kumashiro, S.

    1989-06-01T23:59:59.000Z

    An effective device structure for reducing leakage current in buried heterostructure laser diodes with semiinsulating InP blocking layers has been analyzed with the use of a semiconductor device simulator in which deep trap levels are taken into account. Adding a thin wide-bandgap InGaP layer in the semiinsulating region at the mesa boundaries as a barrier to prevent double injection into the semiinsulating region is predicted to be markedly effective in reducing leakage current.

  17. Spatially Resolved Mapping of Electrical Conductivity around Individual Domain (Grain) Boundaries in Graphene

    SciTech Connect (OSTI)

    Li, An-Ping [ORNL; Clark, Kendal W [ORNL; Zhang, Xiaoguang [ORNL; Vlassiouk, Ivan V [ORNL; He, Guowei [Carnegie Mellon University (CMU); Feenstra, Randall [Carnegie Mellon University (CMU)

    2013-01-01T23:59:59.000Z

    Graphene films can now be produced on the scale of up to meters. However, all large-scale graphene films contain topological defects that can significantly affect the characteristic transport behaviors of graphene. Here, we spatially map the structures and electronic transport near specific domain and grain boundaries in graphene, and evaluate effects of different types of defect on the electronic conductivity in epitaxial graphene grown on SiC and CVD graphene on Cu subsequently transferred to a SiO2 substrate. We use a combined approach with a multi-probe scanning tunneling potentiometry to investigate both structures and transport at individual grain boundaries and domain boundaries that are defined by coalesced grains, surface steps, and changes in layer thickness. It is found that the substrate step on SiC presents a significant potential barrier for electron transport of epitaxial graphene due to the reduced charge transport from the substrate at the step edges, monolayer-bilayer boundaries exhibit a high resistivity that can change depending on directions of the current across the boundary, and the resistivity of grain boundaries changes with the transition width of the disordered region between two adjacent grains in graphene. The detailed understanding of graphene defects will provide the feedback for controlled engineering of defects in large-scale graphene films.

  18. Moment problems and boundaries of number triangles

    E-Print Network [OSTI]

    Gnedin, Alexander

    2008-01-01T23:59:59.000Z

    The boundary problem for graphs like Pascal's but with general multiplicities of edges is related to a `backward' problem of moments of the Hausdorff type.

  19. Performance Boundaries in Nb3Sn Superconductors

    E-Print Network [OSTI]

    Godeke, Arno

    2006-01-01T23:59:59.000Z

    Boundaries in Nb 3 Sn Superconductors – Berkeley, CABoundaries in Nb 3 Sn Superconductors – Berkeley, CABoundaries in Nb 3 Sn Superconductors Arno Godeke Berkeley,

  20. Metal deposition using seed layers

    DOE Patents [OSTI]

    Feng, Hsein-Ping; Chen, Gang; Bo, Yu; Ren, Zhifeng; Chen, Shuo; Poudel, Bed

    2013-11-12T23:59:59.000Z

    Methods of forming a conductive metal layers on substrates are disclosed which employ a seed layer to enhance bonding, especially to smooth, low-roughness or hydrophobic substrates. In one aspect of the invention, the seed layer can be formed by applying nanoparticles onto a surface of the substrate; and the metallization is achieved by electroplating an electrically conducting metal onto the seed layer, whereby the nanoparticles serve as nucleation sites for metal deposition. In another approach, the seed layer can be formed by a self-assembling linker material, such as a sulfur-containing silane material.

  1. Buried oxide layer in silicon

    DOE Patents [OSTI]

    Sadana, Devendra Kumar (Pleasantville, NY); Holland, Orin Wayne (Lenoir, TN)

    2001-01-01T23:59:59.000Z

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  2. The Influence of Grain Boundary Type upon Damage Evolution at Grain Boundary Interfaces

    SciTech Connect (OSTI)

    Perez-Bergquist, Alejandro G [Los Alamos National Laboratory; Brandl, Christian [Los Alamos National Laboratory; Escobedo, Juan P [Los Alamos National Laboratory; Trujillo, Carl P [Los Alamos National Laboratory; Cerreta, Ellen K [Los Alamos National Laboratory; Gray III, George T [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory

    2012-07-09T23:59:59.000Z

    In a prior work, it was found that grain boundary structure strongly influences damage evolution at grain boundaries in copper samples subjected to either shock compression or incipient spall. Here, several grain boundaries with different grain boundary structures, including a {Sigma}3 (10-1) boundary, are interrogated via conventional transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) to investigate the effects of atomic-scale structural differences on grain boundary strength and mobility. Boundaries are studied both before and after shock compression at a peak shock stress of 10 GPa. Results of the TEM and HRTEM work are used in conjunction with MD modeling to propose a model for shock-induced damage evolution at grain boundary interfaces that is dependent upon coincidence.

  3. Analysis of the Younger Dryas Impact Layer

    SciTech Connect (OSTI)

    Firestone, Richard B.; West, Allen; Revay, Zsolt; Hagstrum, Jonathon T,; Belgya, Thomas; Hee, Shane S. Que; Smith, Alan R.

    2010-02-27T23:59:59.000Z

    We have uncovered a thin layer of magnetic grains and microspherules, carbon spherules, and glass-like carbon at nine sites across North America, a site in Belgium, and throughout the rims of 16 Carolina Bays. It is consistent with the ejecta layer from an impact event and has been dated to 12.9 ka BP coinciding with the onset of Younger Dryas (YD) cooling and widespread megafaunal extinctions in North America. At many locations the impact layer is directly below a black mat marking the sudden disappearance of the megafauna and Clovis people. The distribution pattern of the Younger Dryas boundary (YDB) ejecta layer is consistent with an impact near the Great Lakes that deposited terrestrial-like ejecta near the impact site and unusual, titanium-rich projectile-like ejecta further away. High water content associated with the ejecta, up to 28 at. percent hydrogen (H), suggests the impact occurred over the Laurentide Ice Sheet. YDB microspherules and magnetic grains are highly enriched in TiO{sub 2}. Magnetic grains from several sites are enriched in iridium (Ir), up to 117 ppb. The TiO{sub 2}/FeO, K/Th, TiO{sub 2}/Zr, Al{sub 2}O{sub 3}/FeO+MgO, CaO/Al{sub 2}O{sub 3}, REE/ chondrite, FeO/MnO ratios and SiO{sub 2}, Na{sub 2}O, K{sub 2}O, Cr{sub 2}O{sub 3}, Ni, Co, U, Th and other trace element abundances are inconsistent with all terrestrial and extraterrestrial (ET) sources except for KREEP, a lunar igneous rock rich in potassium (K), rare-earth elements (REE), phosphorus (P), and other incompatible elements including U and Th. Normal Fe, Ti, and {sup 238}U/{sup 235}U isotopic abundances were found in the magnetic grains, but {sup 234}U was enriched over equilibrium values by 50 percent in Murray Springs and by 130 percent in Belgium. 40K abundance is enriched by up to 100 percent in YDB sediments and Clovis chert artifacts. Highly vesicular carbon spherules containing nanodiamonds, glass-like carbon, charcoal and soot found in large quantities in the YDB layer are consistent with an impact followed by intense burning. Four holes in the Great Lakes, some deeper than Death Valley, are proposed as possible craters produced by the airburst breakup of a loosely aggregated projectile.

  4. 12th AIAA/CEAS Aeroacoustics Conference, May 8---10, 2006, Cambridge, Massachusetts PML absorbing boundary condition for nonlinear

    E-Print Network [OSTI]

    Hu, Fang Q.

    . R. China Perfectly Matched Layer (PML) absorbing boundary condition for the compressible non­ linear shedding from a viscous flow over a circular cylinder are presented. Satisfactory results demonstrated that the absorbing zone is theoretically reflectionless for multi­dimensional linear waves of any angle and frequency

  5. ASYMPTOTIC MODELLING OF CRYSTALLISATION IN TWO-LAYER SYSTEMS. APPLICATION TO METHANE

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ,b; Skovborg and Rasmussen, 1994 ; Herri et al.,1999). Models generally assume a two-layer configuration which'(z, t) in dissolved gas. Boundary conditions are: c'(0, t) = Cext and c'(, t) = cb(t); Cext is the gas solubility; cb(t) is the bulk concentration. - bulk zone : due to the effect of stirring, concentration

  6. Transverse oscillations in a single-layer dusty plasma under microgravity V. E. Fortov,2

    E-Print Network [OSTI]

    Goree, John

    and A. V. Ivlev3 1 Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242 microgravity conditions. This single layer is confined at a void boundary by a balance of ion drag and electric a source of energy for microparticles. Under microgravity conditions, micropar- ticles are suspended

  7. Interaction of Ekman Layers and Islands MICHAEL A. SPALL AND JOSEPH PEDLOSKY

    E-Print Network [OSTI]

    to that found for the interaction of Ekman layers and an infinite boundary, namely downwelling (upwelling around the island so that the regions of upwelling and downwelling are dynamically connected, for positive wind stress, exhibits an anticyclonic phase rotation with depth (direction of Kelvin wave

  8. SHEAR LAYER INSTABILITY AND MIXING IN MICRO HEAT SPREADERS C. Sert and A. Beskok

    E-Print Network [OSTI]

    Beskok, Ali

    SHEAR LAYER INSTABILITY AND MIXING IN MICRO HEAT SPREADERS C. Sert and A. Beskok Texas A the chip surface temperature by oscillatory flow forced convection and mixing. Numerical simulations are performed for an MHS device with channel to reservoir expansion ratio H/h 25. The boundary conditions

  9. Hybrid asymptotic-finite element method for stiff two-point boundary value problems

    SciTech Connect (OSTI)

    Chin, R.C.Y.; Krasny, R.

    1983-06-01T23:59:59.000Z

    An accurate and efficient numerical method has been developed for a nonlinear stiff second order two-point boundary value problem. The scheme combines asymptotic methods with the usual solution techniques for two-point boundary value problems. A new modification of Newton's method or quasilinearization is used to reduce the nonlinear problem to a sequence of linear problems. The resultant linear problem is solved by patching local solutions at the knots or equivalently by projecting onto an affine subset constructed from asymptotic expansions. In this way, boundary layers are naturally incorporated into the approximation. An adaptive mesh is employed to achieve an error of O(1/N/sup 2/) + O(..sqrt..e). Here, N is the number of intervals and epsilon << 1 is the singular perturbation parameter. Numerical computations are presented.

  10. Boundary Behavior of the Ginzburg-Landau Order Parameter in the Surface Superconductivity Regime

    E-Print Network [OSTI]

    M. Correggi; N. Rougerie

    2015-01-27T23:59:59.000Z

    We study the 2D Ginzburg-Landau theory for a type-II superconductor in an applied magnetic field varying between the second and third critical value. In this regime the order parameter minimizing the GL energy is concentrated along the boundary of the sample and is well approximated to leading order by a simplified 1D profile in the direction perpendicular to the boundary. Motivated by a conjecture of Xing-Bin Pan, we address the question of whether this approximation can hold uniformly in the boundary region. We prove that this is indeed the case as a corollary of a refined, second order energy expansion including contributions due to the curvature of the sample. Local variations of the GL order parameter are controlled by the second order term of this energy expansion, which allows us to prove the desired uniformity of the surface superconductivity layer.

  11. Prediction Error and Event Boundaries 1 Running Head: PREDICTION ERROR AND EVENT BOUNDARIES

    E-Print Network [OSTI]

    Zacks, Jeffrey M.

    Prediction Error and Event Boundaries 1 Running Head: PREDICTION ERROR AND EVENT BOUNDARIES A computational model of event segmentation from perceptual prediction. Jeremy R. Reynolds, Jeffrey M. Zacks, and Todd S. Braver Washington University Manuscript #12;Prediction Error and Event Boundaries 2 People tend

  12. The Daytime Mixed Layer Observed by Radiosonde, Profiler, and LIDAR during MILAGRO

    SciTech Connect (OSTI)

    Shaw, William J.; Pekour, Mikhail S.; Coulter, Richard L.; Martin, Tim J.; Walters, Justin

    2007-10-19T23:59:59.000Z

    During the MILAGRO campaign centered in the Mexico City area, Pacific Northwest National Laboratory (PNNL) and Argonne National Laboratory (ANL) operated several atmospheric profiling systems at Veracruz and at two locations on the Central Mexican Plateau in the region around Mexico City. These systems included radiosondes, wind profilers, a sodar, and an aerosol backscatter lidar. An additional wind profiler was operated by the University of Alabama in Huntsville (UAH) at the Mexican Petroleum Institue (IMP) near the center of Mexico City. Because of the opportunity afforded by collocation of profilers, radiosondes, and a lidar, and because of the importance of boundary layer depth on aerosol properties, we have carried out a comparison of mixed layer depth as determined independently from these three types of measurement systems during the campaign. We have then used results of this comparison and additional measurements to develop a detailed description of the daily structure and evolution of the boundary layer on the Central Mexican Plateau during MILAGRO. Our analysis indicates that the profilers were more consistently successful in establishing the mixing layer depth during the daytime. The boundary layer growth was similar at the three locations, although the mixing layer tended to be slightly deeper in the afternoon in central Mexico City. The sodar showed that convection began about an hour after sunrise. Maximum daily mixed layer depths always reached 2000 m AGL and frequently extended to 4000 m. The rate and variability of mixing layer growth was essentially the same as that observed during the IMADA-AVER campaign in the same season in 1997. This growth did not seem to be related to whether deep convection was reported on a given day. Wind speeds within the boundary layer exhibited a daily low-altitude maximum in the late afternoon with lighter winds aloft, consistent with previous reports of diurnal regional circulations. Norte events, which produced high winds at Veracruz, did not appreciably modulate the winds on the plateau. Finally, despite the typically dry conditions at the surface, radiosonde profiles showed that relative humidity often exceeded 50% in the early morning and in the upper part of the boundary layer.

  13. 2001 TRAFFIC ZONE BOUNDARIES Zone Numbers

    E-Print Network [OSTI]

    Toronto, University of

    2001 TRAFFIC ZONE BOUNDARIES Zone Numbers & Detailed Definitions #12;2001 TRAFFIC ZONE BOUNDARIES of Toronto Joint Program in Transportation January 2003 #12;PREFACE This report presents the 2001 traffic zone numbers by local municipalities in the 2001 TTS survey area. The second part presents detailed

  14. Green's functions for Neumann boundary conditions

    E-Print Network [OSTI]

    Jerrold Franklin

    2012-08-27T23:59:59.000Z

    Green's functions for Neumann boundary conditions have been considered in Math Physics and Electromagnetism textbooks, but special constraints and other properties required for Neumann boundary conditions have generally not been noticed or treated correctly. In this paper, we derive an appropriate Neumann Green's function with these constraints and properties incorporated.

  15. Boundary integral formulation for interfacial cracks in thermodiffusive bimaterials

    E-Print Network [OSTI]

    L. Morini; A. Piccolroaz

    2015-04-29T23:59:59.000Z

    An original boundary integral formulation is proposed for the problem of a semi-infinite crack at the interface between two dissimilar elastic materials in the presence of heat flows and mass diffusion. Symmetric and skew-symmetric weight function matrices are used together with a generalized Betti's reciprocity theorem in order to derive a system of integral equations that relate the applied loading, the temperature and mass concentration fields, the heat and mass fluxes on the fracture surfaces and the resulting crack opening. The obtained integral identities can have many relevant applications, such as for the modelling of crack and damage processes at the interface between different components in electrochemical energy devices characterized by multi-layered structures (solid oxide fuel cells and lithium ions batteries).

  16. Environmental boundaries to energy development

    SciTech Connect (OSTI)

    Trivelpiece, A.W.

    1989-01-01T23:59:59.000Z

    Public concern about the environment, health and safety consequences of energy technology has been growing steadily for more than two decades in the United States. This concern forms an important boundary condition as the United States seeks to develop a new National Energy Strategy. Furthermore, the international aspects of the energy/environment interface such as acid rain global climate change and stratospheric ozone depletion are very prominent in US thinking. In fact, the energy systems of the world are becoming more closely coupled environmentally and otherwise. Now where is this coupling more important than that between the industrialized and developing world; the choices made by each will have profound effects on the other. The development of energy technologies compatible with both economic growth and improving and sustaining environmental quality represents a major R D challenge to the US and USSR. Decision about adoption of new technology and R D priorities can be improved by better measurements of how energy sources and uses are changing throughout the world and better methods to project the potential consequences of these decisions. Such projection require understanding relative risks of alternating existing and evolving technologies. All of these R D areas, technology improvement energy system monitoring and projection and comparative risk assessment are the topics of this seminar. Progress in each may be enhanced by collaboration and cooperation between our two countries. 7 refs., 27 figs., 5 tabs.

  17. Artificial Neural Networks Single Layer Networks Multi Layer Networks Generalization Artificial Neural Networks

    E-Print Network [OSTI]

    Kjellström, Hedvig

    Artificial Neural Networks Single Layer Networks Multi Layer Networks Generalization Artificial Neural Networks Artificial Neural Networks Single Layer Networks Multi Layer Networks Generalization 1 Artificial Neural Networks Properties Applications Classical Examples Biological Background 2 Single Layer

  18. Method of deforming a biaxially textured buffer layer on a textured metallic substrate and articles therefrom

    DOE Patents [OSTI]

    Lee, Dominic F. (Knoxville, TN); Kroeger, Donald M. (Knoxville, TN); Goyal, Amit (Knoxville, TN)

    2000-01-01T23:59:59.000Z

    The present invention provides methods and biaxially textured articles having a deformed epitaxial layer formed therefrom for use with high temperature superconductors, photovoltaic, ferroelectric, or optical devices. A buffer layer is epitaxially deposited onto biaxially-textured substrates and then mechanically deformed. The deformation process minimizes or eliminates grooves, or other irregularities, formed on the buffer layer while maintaining the biaxial texture of the buffer layer. Advantageously, the biaxial texture of the buffer layer is not altered during subsequent heat treatments of the deformed buffer. The present invention provides mechanical densification procedures which can be incorporated into the processing of superconducting films through the powder deposit or precursor approaches without incurring unfavorable high-angle grain boundaries.

  19. Changes in the ocean mixed layer following extraordinary atmospheric forcing. Master's thesis

    SciTech Connect (OSTI)

    Mettlach, T.R.

    1985-12-01T23:59:59.000Z

    A one-dimensional ocean planetary boundary-layer model is used to predict the evolution of the thermal structure of the ocean mixed layer at six locations in the ocean following the hypothetical effects on the atmosphere of a major nuclear war. The inputs to the ocean model are the heat and momentum fluxes computed from a 3D climate model designed to simulate nuclear winter effects in the atmosphere. The experiment gives evidence that the summertime mixed layer can cool 5 C within 30 days and that the effect of increased wind along coastal regions due to sudden ocean-land temperture differences will deepen the mixed layer 20 to 30 meters. The scientific literature on the subject of nuclear winter is reviewed and interpreted to trace the evolution of the nuclear winter hypothesis and to assess the quality of the results of the mixed layer experiment.

  20. Oxygen-reducing catalyst layer

    DOE Patents [OSTI]

    O'Brien, Dennis P. (Maplewood, MN); Schmoeckel, Alison K. (Stillwater, MN); Vernstrom, George D. (Cottage Grove, MN); Atanasoski, Radoslav (Edina, MN); Wood, Thomas E. (Stillwater, MN); Yang, Ruizhi (Halifax, CA); Easton, E. Bradley (Halifax, CA); Dahn, Jeffrey R. (Hubley, CA); O'Neill, David G. (Lake Elmo, MN)

    2011-03-22T23:59:59.000Z

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  1. Boundary definition of a multiverse measure

    E-Print Network [OSTI]

    Raphael Bousso; Ben Freivogel; Stefan Leichenauer; Vladimir Rosenhaus

    2010-09-18T23:59:59.000Z

    We propose to regulate the infinities of eternal inflation by relating a late time cut-off in the bulk to a short distance cut-off on the future boundary. The light-cone time of an event is defined in terms of the volume of its future light-cone on the boundary. We seek an intrinsic definition of boundary volumes that makes no reference to bulk structures. This requires taming the fractal geometry of the future boundary, and lifting the ambiguity of the conformal factor. We propose to work in the conformal frame in which the boundary Ricci scalar is constant. We explore this proposal in the FRW approximation for bubble universes. Remarkably, we find that the future boundary becomes a round three-sphere, with smooth metric on all scales. Our cut-off yields the same relative probabilities as a previous proposal that defined boundary volumes by projection into the bulk along timelike geodesics. Moreover, it is equivalent to an ensemble of causal patches defined without reference to bulk geodesics. It thus yields a holographically motivated and phenomenologically successful measure for eternal inflation.

  2. CATALYZED COMBUSTION IN A FLAT PLATE BOUNDARY LAYER II. NUMERICAL CALCULATIONS

    E-Print Network [OSTI]

    Schefer, R.

    2010-01-01T23:59:59.000Z

    at Simulated Gas Turbine Combustor Operating Conditions",on the use of catalytic combustors for aircraft gas turbineof prototype catalytic combustor configurations. studies are

  3. The effects of sound on the boundary layer of an airfoil at high angles of attack

    E-Print Network [OSTI]

    Hutchinson, Thomas Ira

    1963-01-01T23:59:59.000Z

    were run to determine the lift coefficients for the NACA 4415 airfoil model used. At this time, irreparable internal leaks in the static pressure system of the airfoil were discovered, apparently caused by aging since the airfoil had last been used.... This report also contains an early mention of the use of sound as a means of controlling airflow. This came about while seeking a means of producing artificial disturbances in the airflow of known frequency and amplitude. One of these methods involved...

  4. Wind Energy and the Turbulent Nature of the Atmospheric Boundary Layer

    E-Print Network [OSTI]

    Wächter, Matthias; Hölling, Michael; Morales, Allan; Milan, Patrick; Mücke, Tanja; Peinke, Joachim; Reinke, Nico; Rinn, Philip

    2012-01-01T23:59:59.000Z

    The challenge of developing a sustainable and renewable energy supply within the next decades requires collaborative efforts as well as new concepts in the fields of science and engineering. Here we give an overview on the impact of small-scale properties of atmospheric turbulence on the wind energy conversion process. Special emphasis is given to the noisy and intermittent structure of turbulence and its outcome for wind energy conversion and utilization. Experimental, theoretical, analytical, and numerical concepts and methods are presented. In particular we report on new aspects resulting from the combination of basic research, especially in the field of turbulence and complex stochastic systems, with engineering applications.

  5. CATALYZED COMBUSTION IN A FLAT PLATE BOUNDARY LAYER II. NUMERICAL CALCULATIONS

    E-Print Network [OSTI]

    Schefer, R.

    2010-01-01T23:59:59.000Z

    D.G. , Fourteenth Sympo- sium (International) on Combustion,The Combustion Institute, Pittsburgh, 107 (1973). Wilson,Program for Calculation of Combustion Reaction Equilibrium

  6. CATALYZED COMBUSTION IN A FLAT PLATE BOUNDARY LAYER I. EXPERIMENTAL MEASUREMENTS AND COMPARISON WITH NUMERICAL CALCULATIONS

    E-Print Network [OSTI]

    Robben, R.

    2010-01-01T23:59:59.000Z

    l~ Roberts, "Catathermal Combustion: A New Process for Lm'l-significant gas phase combustion is induced by the presenceInternational) on Combustion (to be published), The

  7. Eos,Vol. 85, No. 23, 8 June 2004 enhanced convergence,boundary layer desta-

    E-Print Network [OSTI]

    Segall, Paul

    -dynamics and aerosol-micro- physics arguments. Human-related activities associated with transportation,energy of the week in NewYork City.This cycle was hypothesized to be related to increased trans- portation activity,the impact of urbanization on net primary productivity (NPP) and its consequences for carbon balance and food

  8. UBL/CLU-ESCOMPTE : THE URBAN BOUNDARY LAYER FIELD EXPERIMENT OVER MARSEILLE AND THE DATA BASE

    E-Print Network [OSTI]

    Boyer, Edmond

    ) thé comparison of thé Town Energy Balance model with thé data obtained over thé city center, (d) thé-comparison of energy flux instrumentations, (b) thé quality évaluation of thé measurements at thé urban stations, (c, among which two on ships, and two in trucks. Thé surface energy budget was measured at 9 sites. Thé

  9. Synoptic and local influences on boundary layer processes, with an application to California wind power

    E-Print Network [OSTI]

    Mansbach, David K

    2010-01-01T23:59:59.000Z

    three California wind farms: San Gorgonio Pass and Tehachapibuoy Ontario San Gorgonio Pass Wind Farm Palm Springs Blytherecords from the San Gorgonio Pass wind farm are not avail-

  10. On the role of monoterpene chemistry in the remote continental boundary layer E. C. Browne1

    E-Print Network [OSTI]

    Meskhidze, Nicholas

    MGLY methyl glyoxal PROPNN propanone nitrate MO2 methyl peroxy radical PYAC pyruvic acid MOBA organic methacrolein nitrate OP2 > C-1 organic peroxides MACRO2 peroxy radicals from MACR ORA1 formic acid MAHP methyl acrylic acid ORA2 acetic and higher acids MCTO alkoxy radicals from methyl catechol oxidation PER1 peroxy

  11. Reactive Halogens in the Marine Boundary Layer (RHaMBLe): the tropical North Atlantic experiments

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    B. , Hebestreit, K. , and Platt, U. : Short-lived alkylR. , Lawrence, M. G. , Platt, U. , ,and Crutzen, P. J. :Peleg, M. , Luria, M. , and Platt, U. : DOAS measurements of

  12. Understanding the role of organic aerosol in the coastal and remote pacic marine boundary layer

    E-Print Network [OSTI]

    Hawkins, Lelia Nahid

    2010-01-01T23:59:59.000Z

    consistent with diesel and oil combustion were also observedwith diesel and residual oil combustion, and has a strongto identify OM from oil combustion, woodsmoke, processed

  13. An efficient approximation for the vibro-acoustic response of a turbulent boundary layer excited panel

    E-Print Network [OSTI]

    Boyer, Edmond

    hal-01004463,version1-11Jun2014 Author manuscript, published in "Journal of Sound and Vibration 264, 4 and the acoustic pressure radiated when a thin elastic plate is immersed in a low Mach number flow of fluid. The mechanical properties of this panel are a Young's modulus E, a Pois- son coefficient and a mass per unit

  14. A BOUNDARY LAYER PROBLEM FOR AN ASYMPTOTIC PRESERVING SCHEME IN THE QUASI-NEUTRAL LIMIT FOR

    E-Print Network [OSTI]

    Vignal, Marie-Hélène

    , see [31]. The second application is related to electric arc phenomena on satellite solar panels, see as the asymptotic pre- serving scheme developed in [9] are unstable for general Roe type solvers when the mesh does, the quasi-neutral model is not valid in non quasi-neutral zones and, we have to use different models

  15. RACORO LONG-TERM, SYSTEMATIC AIRCRAFT OBSERVATIONS OF BOUNDARY LAYER CLOUDS

    E-Print Network [OSTI]

    ). This type of cloud is common globally, and the Earth's radiative energy balance is particularly sensitive the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid to do so, for United States Government purposes. BNL-91362-2010-CP #12;

  16. Design of an Instrumentation System for a Boundary Layer Transition Wing Glove Experiment

    E-Print Network [OSTI]

    Williams, Thomas 1987-

    2012-08-23T23:59:59.000Z

    side of the glove. Infrared (IR) thermography has been selected as the primary transition detection tool. A heat transfer analysis has shown that solar radiation will warm the surface of the glove above the adiabatic wall temperature and therefore...

  17. American Institute of Aeronautics and Astronautics The Influence of Stable Boundary Layer Flows

    E-Print Network [OSTI]

    Manuel, Lance

    generated by shear and destroyed by negative buoyancy. Wind shear (both magnitude and direction) under and forecasting of LLJs is needed for robust wind turbine design and for more reliable power generation prediction on Wind Turbine Fatigue Loads Chungwook Sim1 Dept. of Civil, Architectural, and Environmental Engineering

  18. Reactive Halogens in the Marine Boundary Layer (RHaMBLe): the tropical North Atlantic experiments

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    close to or East of the Canary Islands, before arriving atpassing near to the Canary Islands on its way to Cape Verde.passing close to the Canary islands before approaching Cape

  19. Synoptic and local influences on boundary layer processes, with an application to California wind power

    E-Print Network [OSTI]

    Mansbach, David K.

    2010-01-01T23:59:59.000Z

    maps showing locations of wind power conversion facilities,of US winds and wind power at 80 m derived fromEvaluation of global wind power. Journal of Geo- physical

  20. Study of active control of instability in a boundary layer over a flat plate flow 

    E-Print Network [OSTI]

    Oryu, Hiroshi

    2000-01-01T23:59:59.000Z

    -Sommerfeld equation. The development of a sensor-actuator control system unit using synthetic jet actuators for flow transition control was studied. The implementation of the disturbance generator using a DC motor for the generation of a desired frequency...

  1. Atmospheric Boundary Layer Studies with Unified RANS-LES and Dynamic LES Methods

    E-Print Network [OSTI]

    Heinz, Stefan

    computational cost. Details about the characteristic features of these methods and applications to channel flow and the numerical method applied. The results obtained by unified and dynamic LES models are discussed in section IV of Mechanical Engineering, 1000 E. University Avenue, Laramie WY 82071. PhD student, Department of Mathematics

  2. LES of the adverse-pressure gradient turbulent boundary layer M. Inoue a,

    E-Print Network [OSTI]

    Marusic, Ivan

    at the University of Melbourne wind tunnel where a plate section with zero pressure gradient is followed by section accurate simulations, for example, of separated flow on the wings of airplanes or for flow through turbine such as the amplified wake of the mean velocity profile and the increasing turbulence intensity in the outer region

  3. Large-eddy Simulation of the Nighttime Stable Atmospheric Boundary Layer

    E-Print Network [OSTI]

    Zhou, Bowen

    2012-01-01T23:59:59.000Z

    eddy Simulation of Wind-turbine Wakes: Evaluation of Turbineperformed LES of wind-turbine wakes in neutrally stratified

  4. Study of active control of instability in a boundary layer over a flat plate flow

    E-Print Network [OSTI]

    Oryu, Hiroshi

    2000-01-01T23:59:59.000Z

    ). . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 9 34 Power spectrum and time record at a freestream of 136. 8 mm/s, 2. 5 mm off the bottom wall and 25. 4 mm upstream of the actuator. . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 35 Power specnum and time record at a Ireestream... of 201. 3 mm/s, 2. 5 mm off the bottom wall and 25. 4 mm upstream of the actuator. . . . . . . . . . . . . . . . . . . . . . . . . . . 41 FIGURE Page 36 Power spectrum and time record at a &eestream of 263. 8 mm/s, 2. 5 mm off the bottom wall and 25...

  5. Numerical prediction of the boundary layers in the flow around a cylinder using a fixed

    E-Print Network [OSTI]

    Wapperom, Peter

    .1. (Webster [We2]): A generic real ellipsoid in Cn with n 3 does not admit any umbilical point. Umbilical]. A natural question arising from [We2] is then to ask whether a generic real ellipsoid in C2 shares the same

  6. Synoptic and local influences on boundary layer processes, with an application to California wind power

    E-Print Network [OSTI]

    Mansbach, David K.

    2010-01-01T23:59:59.000Z

    3.4.2 Wind roses . . . . . . . .Figure 5.5: Downscaled wind speed changes and componentin?uences on California’s wind energy resource. Part 1:

  7. investigating the source, transport, and isotope fractionation of water vapor in the atmospheric boundary layer

    E-Print Network [OSTI]

    Minnesota, University of

    investigating the source, transport, and isotope fractionation of water vapor in the atmospheric-portable mixing ratio generator and Rayleigh distillation device, Agricultural and Forest Meteorology, 150, 1607 ratio generator. Incom- ing dry air passes through a molecular sieve and then a stainless steel frit (a

  8. Understanding the role of organic aerosol in the coastal and remote pacic marine boundary layer

    E-Print Network [OSTI]

    Hawkins, Lelia Nahid

    2010-01-01T23:59:59.000Z

    carbon (OC) and for specific components like bacteria and viruses. The production of sea spray from bubble

  9. Synoptic and local influences on boundary layer processes, with an application to California wind power

    E-Print Network [OSTI]

    Mansbach, David K

    2010-01-01T23:59:59.000Z

    power conversion facilities, nearby METARs stations, and other ob- servation and buoypower con- version facilities, nearby METARs stations, and other observation and buoy

  10. Pollution-enhanced reactive chlorine chemistry in the eastern tropical Atlantic boundary layer

    E-Print Network [OSTI]

    2009-01-01T23:59:59.000Z

    doi:10.1029/2008GL036666, 2009 Pollution-enhanced reactiveE. S. Saltzman (2009), Pollution-enhanced reactive chlorine5 L08810 LAWLER ET AL. : POLLUTION-ENHANCED CLX IN THE MBL

  11. Initial-Boundary Layer Associated with the Nonlinear Darcy-Brinkman System

    E-Print Network [OSTI]

    Aluffi, Paolo

    dependent. We also assume the zeroth order compatibility condition v0|z=0,1 = 0. The Darcy-Brinkman equation), the Darcy-Brinkman equation reduces to the classical Darcy equation u = - () 0 [pl]l + lg0 V ez . (1 in system (1.1), we arrive at the following Darcy equation v0 + p0 = F, div v0 = 0, v0 · n|z=0,1 = 0, v0

  12. Motion of a sphere in an oscillatory boundary layer: an optical tweezer based study

    E-Print Network [OSTI]

    Prerna Sharma; Shankar Ghosh; S. Bhattacharya

    2006-08-11T23:59:59.000Z

    The drag forces acting on a single polystyrene sphere in the vicinity of an oscillating glass plate have been measured using an optical tweezer. The phase of the sphere is found to be a sensitive probe of the dynamics of the sphere. The evolution of the phase from an inertially-coupled regime to a purely velocity-coupled regime is explored. Moreover, the frequency dependent response is found to be characteristic of a damped oscillator with an effective inertia which is several orders of magnitude greater than that of the particle.

  13. The effect of periodic-unsteady wakes, curvature, and pressure gradient on boundary-layer transition

    E-Print Network [OSTI]

    Radke, Robert Edward

    1994-01-01T23:59:59.000Z

    generator cross section looking upstream . . Test section with the curved plate located at the mid-height of the channel Page 10 12 Figure 4. Figure 5. 14 Curved plate detail drawing with side and top views Cross-sections A-A (showing the internal... for the next generation of research in this area will be accomplished. 10 4. TEST FACILITY AND MEASUREMENT TECHNIQUE 4. 1 Wind Tunnel The test facility in Figure 1 is described in Schobeiri and Pardivala (1992) in detaiL The air is supplied with a...

  14. Observations of gas phase hydrochloric acid in the polluted marine boundary layer

    E-Print Network [OSTI]

    , California, USA, 2 Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA Ship-based measurements of gas phase hydrochloric acid (HCl), particulate chloride (p the lifetime of methane [Finlayson-Pitts, 1993; Pszenny et al., 2007; Singh and Kasting, 1988; von Glasow

  15. A deterministic model for the sublayer streaks in turbulent boundary layers for application

    E-Print Network [OSTI]

    Davies, Christopher

    control BY PETER W. CARPENTER 1,*, KAREN L. KUDAR 1 , REZA ALI 1 , PRADEEP K. SEN 2 AND CHRISTOPHER DAVIES

  16. Surface heterogeneity impacts on boundary layer dynamics via energy balance partitioning

    E-Print Network [OSTI]

    Brunsell, Nathaniel A.; Mechem, David B.; Anderson, M. C.

    2011-04-11T23:59:59.000Z

    .23 0.0002 1600 309.19 2.04 0.21 0.0012 12800 308.06 3.15 0.23 0.0017 u3 100 307.07 4.97 0.22 0.0030 200 306.31 0.54 0.22 0.0003 1600 307.34 2.17 0.21 0.0019 12800 306.13 3.15 0.22 0.0019 u6 100 305.38 5.65 0.21 0.0043 200 304.87 0.50 0.22 0.0004 1600...

  17. Measurement of three-dimensional coherent fluid structure in high Reynolds number turbulent boundary layers

    E-Print Network [OSTI]

    Clark, Thomas Henry

    2012-07-03T23:59:59.000Z

    of difference between original and filled-in vectors . . 158 6.22 Restoration of field with 20% missing data . . . . . . . . . . . . . 160 6.23 Restoration of field with 50% missing data . . . . . . . . . . . . . 161 6.24 Median error in restoration of a field... Binary mask used to relate pixel indices in matrix Wij to the reduced pixel indices in Wrs. ?js Binary mask used to relate voxel indices in matrix Wij to the reduced voxel indices in Wrs. ei Error in the ith velocity component. u?iu ? j u? Turbulent...

  18. Synoptic and local influences on boundary layer processes, with an application to California wind power

    E-Print Network [OSTI]

    Mansbach, David K.

    2010-01-01T23:59:59.000Z

    of observed summertime mesoscale pressure gradient and ??observed wind speeds and mesoscale SLP di?erences at pointsand modi?cation of mesoscale circulations. Monthly Weather

  19. Hygroscopic growth of submicron and supermicron aerosols in the marine boundary layer

    E-Print Network [OSTI]

    balance and climate directly through absorption and scattering of the incoming solar radiation and indirectly through modification of cloud properties [Intergovernmental Panel on Climate Change, 2007 behaviors of the dynamic and complex atmospheric aerosol consisting of particles with a wide range of sizes

  20. An Examination of Configurations for Using Infrared to Measure Boundary Layer Transition

    E-Print Network [OSTI]

    Freels, Justin Reed

    2012-10-19T23:59:59.000Z

    as an external source and circulating fluid inside of the airfoil. Furthermore, ABS plastic and aluminum airfoils are tested with and without coatings such as black paint and surface wraps. The results show that thermal conduction within the model and surface...

  1. Advances in Differential Equations Volume xx, Number xxx, , Pages xxxx BOUNDARY LAYER FOR A PENALIZATION METHOD

    E-Print Network [OSTI]

    Carbou, Gilles

    experiments. To obtain these results we perform an asymptotic expansion of the solution in the spirit of BKW the BKW method is that one has to obtain very regular solutions on the limit problem. 1.1. Main results

  2. Viscous boundary layers for the NavierStokes equations with the Navier slip conditions

    E-Print Network [OSTI]

    Iftimie, Dragoº

    , such as in aerodynamics (space shuttles covered by tiles), in weather forecast (where trees, buildings, water waves have that the Navier slip­with­friction condition was derived in the kinematic theory of gases by Maxwell. In this case

  3. Viscous boundary layers for the Navier-Stokes equations with the Navier slip conditions

    E-Print Network [OSTI]

    Sueur, Franck

    , such as in aerodynamics (space shuttles covered by tiles), in weather forecast (where trees, buildings, water waves have that the Navier slip-with-friction condition was derived in the kinematic theory of gases by Maxwell. In this case

  4. Solute dispersion in the coastal boundary layer of southern Lake Michigan

    E-Print Network [OSTI]

    of southern Lake Michigan, J. Geophys. Res. Oceans, 118, 1606­1617, doi:10.1002/jgrc.20136. 1. Introduction [2) with turbid waters contributing to increased survival by limiting sunlight penetration, removal of bacteria

  5. Understanding the role of organic aerosol in the coastal and remote pacic marine boundary layer

    E-Print Network [OSTI]

    Hawkins, Lelia Nahid

    2010-01-01T23:59:59.000Z

    2.2.2 FTIR and XRF analyses . . . . . . . . . . . . . .Ray Fluorescence (XRF) . . . . . . . . . . 4.2.3 Quadrupoleof OM (by mass), sum of XRF elements K, Ni, Ca, Fe, Sn, V,

  6. Reactive Halogens in the Marine Boundary Layer (RHaMBLe): the tropical North Atlantic experiments

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    105, 24191–24204, 2000. Allan, B. J. , Plane J. M. C. , andlayer, Geophys. Res. Lett. , Allan, J. D. , Topping, D. O. ,1,2 , G. McFiggans 3 , J. D. Allan 3,4 , A. R. Baker 5 , S.

  7. Primary crossflow vortices, secondary absolute instabilities and their control in the rotating-disk boundary layer

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Primary crossflow vortices, secondary absolute instabilities and their control in the rotating patterns of crossflow vortices are derived by employing asymptotic techniques. This approach accounts three-dimensional velocity profiles, are subject to inviscid crossflow in- stabilities and rapidly

  8. Field boundary layer characteristics as modified by clams in habitats of varying survival rates

    E-Print Network [OSTI]

    Profile u (m s-1) y(m) Q (m3 s-1) Vertical Jet + = Q UU -Vertical jets in crossflow have been shown as those in the jets-in-crossflow literature. Hypothesis and Objective · Hypothesis: Clam presence

  9. High-Speed Boundary-Layer Transition : : Study of Stationary Crossflow Using Spectral Analysis

    E-Print Network [OSTI]

    McGuire, Patrick Joseph

    2014-01-01T23:59:59.000Z

    Secondary Instability of Crossflow Vortices. J. Fluid Mech.R. & S ARIC , W. S. 1999 Crossflow Stability and TransitionSaturation of Stationary Crossflow Vortices in a Swept-Wing

  10. American Institute of Aeronautics and Astronautics Shock/Boundary Layer Interaction Effects on Transverse

    E-Print Network [OSTI]

    Texas at Arlington, University of

    on Transverse Jets in Crossflow Over a Flat Plate Dean A. Dickmann* Lockheed Martin Missiles and Fire Control crossflow by bifurcating the phase portrait of the separation topology through the addition of saddle points

  11. Particle Resuspension in Turbulent Boundary Layers and the Influence of Non-Gaussian Removal Forces

    E-Print Network [OSTI]

    Zhang, F; Kissane, M

    2012-01-01T23:59:59.000Z

    The work presented is concerned with the way very small micron-size particles attached to a surface are resuspended when exposed to a turbulent flow. Of particular concern is the remobilization of radioactive particles as a consequence of potential nuclear accidents. In this particular case the focus is on small particles, resuspension involving the rocking and rolling of a particle about surface asperities arising from the moments of the fluctuating drag forces acting on the particle close to the surface. In this work the model is significantly improved by using values of both the stream-wise fluid velocity and acceleration close to the wall obtained from Direct Numerical Simulation (DNS) of turbulent channelflow. Using an...

  12. Improving tropical and subtropical boundary layer cloudiness in the NCEP GFS

    E-Print Network [OSTI]

    Bretherton, Chris

    , as well as in the Community Earth System Model (CESM, http://www.cesm.ucar.edu/), using the relative

  13. Turbulent boundary layers interacting with groups of obstacles Project Staff Principal investigator: Dr Costantino Manes

    E-Print Network [OSTI]

    Sóbester, András

    (wind or marine) can generate, estimating carbon dioxide exchange between forests and the atmosphere-Dimensional (2-D) flow, where mean turbulent properties are uniform (or almost uniform) along one direction

  14. Understanding the role of organic aerosol in the coastal and remote pacic marine boundary layer

    E-Print Network [OSTI]

    Hawkins, Lelia Nahid

    2010-01-01T23:59:59.000Z

    show: aluminum (solid red bowtie), silicon (solid bluesolid turquoise vertical bowtie), calcium (solid orangeshow: aluminum (solid red bowtie), silicon (solid blue

  15. THE THERMODYNAMIC EFFECTS OF SUBLIMATING, BLOWING SNOW IN THE ATMOSPHERIC BOUNDARY LAYER

    E-Print Network [OSTI]

    Dery, Stephen

    . Apart from the transport of snow, the thermodynamic impact of sublimat- ing blowing snow in air near process is self- limiting despite ongoing transport of snow by wind, yielding significantly lower values their lengthy winters (Stewart et al., 1995). These storms are often associated with sub-freezing temper- atures

  16. Numerical Study of Freestream Waves Receptivity and Nonlinear Breakdown in Hypersonic Boundary Layer

    E-Print Network [OSTI]

    Lei, Jia

    2013-01-01T23:59:59.000Z

    each fixed-frequency disturbance can be represented by eq. (and LST with the disturbance frequency of 744.5 kHz for theDNS and LST at the disturbance frequency of 744.5 kHz for

  17. Buoyancy Effects on the Scaling Characteristics of Atmospheric Boundary Layer Wind Fields in the Mesoscale Range

    E-Print Network [OSTI]

    Kiliyanpilakkil, V P; Ruiz-Columbié, A; Araya, G; Castillo, L; Hirth, B; Burgett, W

    2015-01-01T23:59:59.000Z

    We have analyzed long-term wind speed time-series from five field sites up to a height of 300 m from the ground. Structure function-based scaling analysis has revealed that the scaling exponents in the mesoscale regime systematically depend on height. This anomalous behavior is shown to be caused by the buoyancy effects. In the framework of the extended self-similarity, the relative scaling exponents portray quasi-universal behavior.

  18. Momentum and thermal boundary-layer thickness in a stagnation flow chemical vapor deposition reactor

    E-Print Network [OSTI]

    Dandy, David

    reactor David S. Dandy and Jungheum Yun Department of Chemical Engineering, Colorado State University stagnation flows characteristic of highly convective chemical vapor deposition pedestal reactors. Expressions of diamond via low- pressure chemical vapor deposition, direct current (dc) arcjet reactor systems3­8 have

  19. The development of a low velocity wind tunnel with instrumentation for boundary layer investigations

    E-Print Network [OSTI]

    Massey, John Robert

    1958-01-01T23:59:59.000Z

    . Complete leakage tests were made, and the leaks so detected were sealed with Glyptal. Though closing the leaks greatly improved the results, unacceptable differences remained in velocity measure? 45 ments. For example, the recorder continued to have...

  20. Boundary-Layer Meteorol DOI 10.1007/s10546-010-9529-5

    E-Print Network [OSTI]

    Minnesota, University of

    ). A considerable amount of isotope research has focused on the condensed phase. However, the analysis of water compared using EC-TDL and traditional eddy-covariance and infrared gas analyser techniques over a soybean

  1. Synoptic and local influences on boundary layer processes, with an application to California wind power

    E-Print Network [OSTI]

    Mansbach, David K.

    2010-01-01T23:59:59.000Z

    near three California wind farms are then explored: Sancirculations that drive wind farms, and to consider the e?at three major California wind farms. This is clearly a much

  2. Large-eddy Simulation of the Nighttime Stable Atmospheric Boundary Layer

    E-Print Network [OSTI]

    Zhou, Bowen

    2012-01-01T23:59:59.000Z

    coordinate and (b) wind and potential temperature at the up-coordinate and (b) wind and potential temperature at the up-Mean profiles of wind and potential temperature, turbulent

  3. Synoptic and local influences on boundary layer processes, with an application to California wind power

    E-Print Network [OSTI]

    Mansbach, David K.

    2010-01-01T23:59:59.000Z

    California o?shore wind energy potential. Renewable Energy,2008: Ex- ploring wind energy potential o? the Californiafor estimates of wind power potential. Journal of Applied

  4. Surface and bottom boundary layer dynamics on a shallow submarine bank : southern flank of Georges Bank

    E-Print Network [OSTI]

    Werner, Sandra R. (Sandra Regina)

    1999-01-01T23:59:59.000Z

    The thesis investigates the circulation at a 76-m deep study site on the southern flank of Georges Bank, a shallow submarine bank located between the deeper Gulf of Maine and the continental slope. Emphasis is placed on ...

  5. OBSERVATIONS AND PARAMETERIZATION OF BOUNDARY LAYER STRUCTURES AND CLOUDS AT THE ARM TWP NAURU SITE

    E-Print Network [OSTI]

    .S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United-time winds observed at Nauru are very steady from the East during the entire observing period. An excellent of the island) from satellite estimates and the temperature, moisture, and wind observations from the Nauru site

  6. Non-linear modulation of a boundary layer induced by vortex generators

    E-Print Network [OSTI]

    Wesfreid, José Eduardo

    the efficiency of static mixers.6 Nevertheless, the question of the choice and design of the proper VG

  7. Acidbase chemical reaction model for nucleation rates in the polluted atmospheric boundary layer

    E-Print Network [OSTI]

    June 18, 2012) Climate models show that particles formed by nucleation can affect cloud cover and, therefore, the earth's radiation budget. Measurements worldwide show that nucleation rates in the atmo be a significant source of condensation nuclei (2) and cloud condensation nuclei (CCN) (3). The cloud albedo effect

  8. Sensitivity of TOMS aerosol index to boundary layer height: Implications for detection of mineral aerosol sources

    E-Print Network [OSTI]

    Mahowald, Natalie

    (using a threshold of 0.7, except over North Africa, the Middle East and Central Asia where the threshold

  9. DOE/SC-ARM-14-034 Lower Atmospheric Boundary Layer Experiment

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisitingContract Management Fermi SitePARTOffice ofHale Plan24,7,INL is62 The35414

  10. DOE/SC-ARM/TR-132 Planetary Boundary Layer (PBL) Height Value

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisitingContract Management Fermi SitePARTOffice ofHale Plan24,7,INL42 ARM15 ARM34892

  11. Posters Triggering of Boundary Layer Cumulus Clouds Over a Heterogeneous Surface

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible forPortsmouth/Paducah Project Office PressPostdoctoraldecadal observations71971173137355

  12. Local Correlations and Multi-Fractal Behaviour in Marine Boundary Layer Cloud Dynamics

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5Let usNucleartearing mode flows andPress) |Local

  13. Characterization of Radar Boundary Layer Data Collected During the 2001 Multi-Frequency Radar IOP

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t z C oCNMSStaffCeriumfor theChapter 3Characterization

  14. Simulation of Post-Frontal Boundary Layers Observed During the ARM 2000 Cloud IOP

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our Instagram Secretary Moniz9Morgan McCorkle Communications andin

  15. Regional Scale Surface CO2 Exchange Estimates Using a Boundary Layer Budget

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection RadiationRecord-SettingHead5"Redline"Method over the

  16. Sensitivity of Boundary-layer and Deep Convective Cloud Simulations to

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our Instagram Secretary Moniz is TakingDepartmentSensitivities of SCMs to

  17. Four-Dimensional Data Assimilation Boundary-Layer Observations Over the Southern

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist.Newof Energy Forrestal Garage

  18. Deformation-Twin-Induced Grain Boundary Failure

    SciTech Connect (OSTI)

    Yongfeng Zhang; Paul C. MIllett; Michael Tonks; Bulent Biner

    2012-01-01T23:59:59.000Z

    This work presents a mechanism of deformation-twin-induced grain boundary failure, and demonstrates the mechanism using molecular dynamics simulations. Deformation twinning is observed as the dominant mechanism during tensile deformation of columnar nanocrystalline body-centered cubic Mo. As a twin approaches a grain boundary, local stress concentration develops due to the incompatible plastic deformations in the two neighboring grains. The magnitude of the stress concentration increases as the twin widens, leading to grain boundary cracking by nucleation and coalescence of microcracks/voids.

  19. Atomistic Simulation of Slow Grain Boundary Motion

    SciTech Connect (OSTI)

    Deng Chuang; Schuh, Christopher A. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States)

    2011-01-28T23:59:59.000Z

    Existing atomistic simulation techniques to study grain boundary motion are usually limited to either high velocities or temperatures and are difficult to compare to realistic experimental conditions. Here we introduce an adapted simulation method that can access boundary velocities in the experimental range and extract mobilities in the zero driving force limit at temperatures as low as {approx}0.2T{sub m} (T{sub m} is the melting point). The method reveals three mechanistic regimes of boundary mobility at zero net velocity depending on the system temperature.

  20. New Boundaries for the B-Model

    E-Print Network [OSTI]

    Bergman, Aaron

    2008-01-01T23:59:59.000Z

    Witten couples the open topological B-model to a holomorphic vector bundle by adding to the boundary of the worldsheet a Wilson loop for an integrable connection on the bundle. Using the descent procedure for boundary vertex operators in this context, I generalize this construction to write a worldsheet coupling for a graded vector bundle with an integrable superconnection. I then compute the open string vertex operators between two such boundaries. A theorem of J. Block gives that this is equivalent to coupling the B-model to an arbitrary object in the derived category.

  1. From Neuman to Dirichlet boundary conditions

    SciTech Connect (OSTI)

    Nikolic, B.; Sazdovic, B. [Institute of Physics, 11001 Belgrade, P.O.Box 57 (Serbia and Montenegro)

    2007-04-23T23:59:59.000Z

    The Dirichlet boundary conditions for the end-point of the open string define Dp-brane. It is parameterized by the rest of coordinates, with Neuman boundary conditions. The relations between background fields can produce the local gauge symmetries of the world-sheet action. After gauge fixing, some Neuman boundary conditions turn into the Dirichlet ones, decreasing the number of Dp-brane dimensions. The physical Dp-brane is gauge invariant part of the initial one. The gauge invariant coordinates are expressed as linear combinations of the effective coordinates and momenta. This fact explains the origin of non-commutativity and the existence of commutative Dp-brane coordinates.

  2. Cobalt disilicide buffer layer for YBCO film on silicon

    SciTech Connect (OSTI)

    Belousov, I.; Rudenko, E. [Institute for Physic Metals, Kiev (Ukraine); Linzen, S.; Seidel, P. [Friedrich-Schiller-Universitaet Jena (Germany)] [Friedrich-Shiller-Universitaet Jena (Germany)

    1997-02-01T23:59:59.000Z

    The CoSi{sub 2} films were used as buffer layers of YBCO/CoSi{sub 2}/Si(100), YBCO/ZrO{sub 2}/CoSi{sub 2}/Si(100) and YBCO/CeO{sub 2}/YSZ/CoSi{sub 2}/epi-Si/Al{sub 2}O{sub 3} heterostructures in this work. Transition temperatures of YBCO films were obtained up to 86K for YBCO films deposited by laser ablation on the top of CeO{sub 2}/YSZ/CoSi{sub 2}/Si/Al{sub 2}O{sub 3} structure. Local nucleation on the crystal defects of silicon, the phenomenon of lateral directed growth (DLG) and agglomeration of CoSi{sub 2} phase are responsible for grain boundaries (GB) position in CoSi{sub 2} layer and its roughness. The roughness was decreased using an additional Zr film on the top structure.

  3. Network layer Connectionless datagram forwarding

    E-Print Network [OSTI]

    (passed down by transport layer) into datagrams Destination host delivers segments up to transport layer by the cold war " If there exists a path, routers will put it in the routing table automatically Forwarding in the original order Physical Link Network Transport Application Physical Link Network Transport Application

  4. Effect of Ti and In/sub 2/O/sub 3/ layers on stability of TbFeCo magneto-optical media on a polycarbonate substrate

    SciTech Connect (OSTI)

    Sekiya, M.; Sato, T.; Chiba, K.; Sobajima, S.

    1988-11-01T23:59:59.000Z

    A new multi-layer structure of magneto-optical medium comprising TbFeCo and an improved dielectric layer was presented. The structure was polycarbonate(PC)/In/sub 2/O/sub 3/(700A)/Ti(15A)/TbFeCo(400A)/Ti(500A) whose thickness was calculated to be optimum for C/N characteristics. A dielectric layer of In/sub 2/O/sub 3/ had a strong affinity to a polycarbonate surface even in an environment at 80/sup 0/C and 85%RH. The stability of oxide-metal boundary, that is In/sub 2/O/sub 3/ and TbFeCo was investigated in detail by Auger electron spectroscopy (AES). The AES spectra of terbium near the boundary showed anomalously without a titanium inter-layer, whereas a small amount of titanium atoms at the contact surface stabilized the boundary.

  5. Nonlinear boundary value problem of magnetic insulation

    E-Print Network [OSTI]

    A. V. Sinitsyn

    2000-09-09T23:59:59.000Z

    On the basis of generalization of upper and lower solution method to the singular two point boundary value problems, the existence theorem of solutions for the system, which models a process of magnetic insulation in plasma is proved.

  6. Topological analysis of the grain boundary space

    E-Print Network [OSTI]

    Patala, Srikanth

    2011-01-01T23:59:59.000Z

    Grain boundaries and their networks have a profound influence on the functional and structural properties of every class of polycrystalline materials and play a critical role in structural evolution and phase transformations. ...

  7. Nonuniqeness in a free boundary problem from combustion

    E-Print Network [OSTI]

    2014-10-31T23:59:59.000Z

    A free boundary problem from combustion. One-phase parabolic free boundary problem with fixed gradient condition. Given u ? C (n), u ?. A. Petrosyan.

  8. Techno-Economic Boundary Analysis of Biological Pathways to Hydrogen...

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

    Techno-Economic Boundary Analysis of Biological Pathways to Hydrogen Production (2009) Techno-Economic Boundary Analysis of Biological Pathways to Hydrogen Production (2009)...

  9. Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries...

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

    Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries. Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries. Abstract: Structure and electronic properties of...

  10. Effects of Transition Metals on the Grain Boundary Cohesion in...

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

    Transition Metals on the Grain Boundary Cohesion in Tungsten. Effects of Transition Metals on the Grain Boundary Cohesion in Tungsten. Abstract: We report on the effects of...

  11. Boundary and Exterior of a Multiset Topology

    E-Print Network [OSTI]

    J. Mahanta; D. Das

    2015-01-26T23:59:59.000Z

    The concepts of exterior and boundary in multiset topological space are introduced. We further established few relationships between the concepts of boundary, closure, exterior and interior of an M- set. These concepts have been pigeonholed by other existing notions viz., open sets, closed sets, clopen sets and limit points. The necessary and sufficient condition for a multiset to have an empty exterior is also discussed.

  12. Nanostructured GaN Nucleation Layer for Light-Emitting Diodes

    SciTech Connect (OSTI)

    Narayan, Jagdish [North Carolina State University; Pant, Punam [North Carolina State University; Wei, Wei [North Carolina State University; Narayan, Roger [University of North Carolina, Chapel Hill; Budai, John D [ORNL

    2007-01-01T23:59:59.000Z

    This paper addresses the formation of nanostructured gallium nitride nucleation (NL) or initial layer (IL), which is necessary to obtain a smooth surface morphology and reduce defects in h-GaN layers for light-emitting diodes and lasers. From detailed X-ray and HR-TEM studies, researchers determined that this layer consists of nanostructured grains with average grain size of 25 nm, which are separated by small-angle grain boundaries (with misorientation 1 ), known as subgrain boundaries. Thus NL is considered to be single-crystal layer with mosaicity of about 1 . These nc grains are mostly faulted cubic GaN (c-GaN) and a small fraction of unfaulted c-GaN. This unfaulted Zinc-blende c-GaN, which is considered a nonequilibrium phase, often appears as embedded or occluded within the faulted c-GaN. The NL layer contained in-plane tensile strain, presumably arising from defects due to island coalescence during Volmer-Weber growth. The 10L X-ray scans showed c-GaN fraction to be over 63% and the rest h-GaN. The NL layer grows epitaxially with the (0001) sapphire substrate by domain matching epitaxy, and this epitaxial relationship is remarkably maintained when c-GaN converts into h-GaN during high-temperature growth.

  13. Study of LATERAL ORGAN BOUNDARIES (LOB) Genetic Pathways in Boundary Maintenance of Arabidopsis

    E-Print Network [OSTI]

    Yu, Lifeng

    2012-01-01T23:59:59.000Z

    Boundary formation and maintenance in tissue development.2002). Shoot meristem maintenance is controlled by a GRAS-et al. , 2005). The maintenance of the polarity of GA

  14. Boundary energy of the open XXX chain with a non-diagonal boundary term

    E-Print Network [OSTI]

    Nepomechie, Rafael I

    2013-01-01T23:59:59.000Z

    We analyze the ground state of the open spin-1/2 isotropic quantum spin chain with a non-diagonal boundary term using a recently proposed Bethe ansatz solution. As the coefficient of the non-diagonal boundary term tends to zero, the Bethe roots split evenly into two sets: those that remain finite, and those that become infinite. We argue that the former satisfy conventional Bethe equations, while the latter satisfy a generalization of the Richardson-Gaudin equations. We derive an expression for the leading correction to the boundary energy in terms of the boundary parameters.

  15. Boundary energy of the open XXX chain with a non-diagonal boundary term

    E-Print Network [OSTI]

    Rafael I. Nepomechie; Chunguang Wang

    2014-01-07T23:59:59.000Z

    We analyze the ground state of the open spin-1/2 isotropic quantum spin chain with a non-diagonal boundary term using a recently proposed Bethe ansatz solution. As the coefficient of the non-diagonal boundary term tends to zero, the Bethe roots split evenly into two sets: those that remain finite, and those that become infinite. We argue that the former satisfy conventional Bethe equations, while the latter satisfy a generalization of the Richardson-Gaudin equations. We derive an expression for the leading correction to the boundary energy in terms of the boundary parameters.

  16. D0 layer 0 innermost layer of silicon microstrip tracker

    SciTech Connect (OSTI)

    Hanagaki, K.; /Fermilab

    2006-01-01T23:59:59.000Z

    A new inner layer silicon strip detector has been built and will be installed in the existing silicon microstrip tracker in D0. They report on the motivation, design, and performance of this new detector.

  17. General Comparison of Power Loss in Single-Layer and Multi-Layer Windings

    E-Print Network [OSTI]

    General Comparison of Power Loss in Single-Layer and Multi-Layer Windings M. E. Dale C. R. Sullivan the IEEE. #12;General Comparison of Power Loss in Single-Layer and Multi-Layer Windings Magdalena E. Dale

  18. Artificial Neural Networks Single Layer Networks Multi Layer Networks Generalization Artificial Neural Networks

    E-Print Network [OSTI]

    Kjellström, Hedvig

    Artificial Neural Networks Single Layer Networks Multi Layer Networks Generalization Artificial Neural Networks #12;Artificial Neural Networks Single Layer Networks Multi Layer Networks Generalization 1 Artificial Neural Networks Properties Applications Classical Examples Biological Background 2

  19. Surface and grain boundary scattering in nanometric Cu thin films: A quantitative analysis including twin boundaries

    SciTech Connect (OSTI)

    Barmak, Katayun [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 and Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Darbal, Amith [Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Ganesh, Kameswaran J.; Ferreira, Paulo J. [Materials Science and Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712 (United States); Rickman, Jeffrey M. [Department of Materials Science and Engineering and Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Sun, Tik; Yao, Bo; Warren, Andrew P.; Coffey, Kevin R., E-mail: kb2612@columbia.edu [Department of Materials Science and Engineering, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States)

    2014-11-01T23:59:59.000Z

    The relative contributions of various defects to the measured resistivity in nanocrystalline Cu were investigated, including a quantitative account of twin-boundary scattering. It has been difficult to quantitatively assess the impact twin boundary scattering has on the classical size effect of electrical resistivity, due to limitations in characterizing twin boundaries in nanocrystalline Cu. In this study, crystal orientation maps of nanocrystalline Cu films were obtained via precession-assisted electron diffraction in the transmission electron microscope. These orientation images were used to characterize grain boundaries and to measure the average grain size of a microstructure, with and without considering twin boundaries. The results of these studies indicate that the contribution from grain-boundary scattering is the dominant factor (as compared to surface scattering) leading to enhanced resistivity. The resistivity data can be well-described by the combined Fuchs–Sondheimer surface scattering model and Mayadas–Shatzkes grain-boundary scattering model using Matthiessen's rule with a surface specularity coefficient of p?=?0.48 and a grain-boundary reflection coefficient of R?=?0.26.

  20. Hybrid window layer for photovoltaic cells

    DOE Patents [OSTI]

    Deng, Xunming (Syvania, OH)

    2010-02-23T23:59:59.000Z

    A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

  1. The limited growth of vegetated shear layers

    E-Print Network [OSTI]

    Ghisalberti, M.

    In contrast to free shear layers, which grow continuously downstream, shear layers generated by submerged vegetation grow only to a finite thickness. Because these shear layers are characterized by coherent vortex structures ...

  2. Hybrid window layer for photovoltaic cells

    DOE Patents [OSTI]

    Deng, Xunming (Syvania, OH); Liao, Xianbo (Toledo, OH); Du, Wenhui (Toledo, OH)

    2011-10-04T23:59:59.000Z

    A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

  3. Hybrid window layer for photovoltaic cells

    DOE Patents [OSTI]

    Deng, Xunming (Sylvania, OH); Liao, Xianbo (Toledo, OH); Du, Wenhui (Toledo, OH)

    2011-02-01T23:59:59.000Z

    A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

  4. Dynamics of multiple double layers in high pressure glow discharge in a simple torus

    SciTech Connect (OSTI)

    Kumar Paul, Manash, E-mail: manashkr@gmail.com [Department of Physics, National Institute of Technology Agartala, Tripura–799 046 (India); Sharma, P. K.; Thakur, A.; Kulkarni, S. V.; Bora, D. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat–382 428 (India)

    2014-06-15T23:59:59.000Z

    Parametric characterization of multiple double layers is done during high pressure glow discharge in a toroidal vessel of small aspect ratio. Although glow discharge (without magnetic field) is known to be independent of device geometry, but the toroidal boundary conditions are conducive to plasma growth and eventually the plasma occupy the toroidal volume partially. At higher anode potential, the visibly glowing spots on the body of spatially extended anode transform into multiple intensely luminous spherical plasma blob structures attached to the tip of the positive electrode. Dynamics of multiple double layers are observed in argon glow discharge plasma in presence of toroidal magnetic field. The radial profiles of plasma parameters measured at various toroidal locations show signatures of double layer formation in our system. Parametric dependence of double layer dynamics in presence of toroidal magnetic field is presented here.

  5. Do grain boundaries in nanophase metals slide?

    SciTech Connect (OSTI)

    Bringa, E M; Leveugle, E; Caro, A

    2006-10-27T23:59:59.000Z

    Nanophase metallic materials show a maximum in strength as grain size decreases to the nano scale, indicating a break down of the Hall-Petch relation. Grain boundary sliding, as a possible accommodation mechanisms, is often the picture that explain computer simulations results and real experiments. In a recent paper, Bringa et al. Science 309, 1838 (2005), we report on the observation of an ultra-hard behavior in nanophase Cu under shock loading, explained in terms of a reduction of grain boundary sliding under the influence of the shock pressure. In this work we perform a detailed study of the effects of hydrostatic pressure on nanophase Cu plasticity and find that it can be understood in terms of pressure dependent grain boundary sliding controlled by a Mohr-Coulomb law.

  6. Wireless boundary monitor system and method

    DOE Patents [OSTI]

    Haynes, H.D.; Ayers, C.W.

    1997-12-09T23:59:59.000Z

    A wireless boundary monitor system used to monitor the integrity of a boundary surrounding an area uses at least two housings having at least one transmitting means for emitting ultrasonic pressure waves to a medium. Each of the housings has a plurality of receiving means for sensing the pressure waves in the medium. The transmitting means and the receiving means of each housing are aimable and communicably linked. At least one of the housings is equipped with a local alarm means for emitting a first alarm indication whereby, when the pressure waves propagating from a transmitting means to a receiving means are sufficiently blocked by an object a local alarm means or a remote alarm means or a combination thereof emit respective alarm indications. The system may be reset either manually or automatically. This wireless boundary monitor system has useful applications in both indoor and outdoor environments. 4 figs.

  7. Pathintegral Monte Carlo simulation of the second layer of 4 He adsorbed on graphite Marlon Pierce and Efstratios Manousakis

    E-Print Network [OSTI]

    Manousakis, Efstratios

    boundaries are in agreement with heat capacity and torsional oscillator measurements, and demonstrate years. Extensive heat capacity measurements 4,5 of the first six layers have been performed of increasing density, a superfluid liquid phase, a A73A7 commensurate solid phase that is registered

  8. Conditions for establishing quasistable double layers in the Earth's auroral upward current region

    SciTech Connect (OSTI)

    Main, D. S. [Department of Physics, John Brown University, Siloam Springs, Arkansas 72761 (United States); Newman, D. L. [Center for Integrated Plasma Studies, University of Colorado, Boulder, Colorado 80309 (United States); Ergun, R. E. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303 (United States)

    2010-12-15T23:59:59.000Z

    The strength and stability of simulated double layers at the ionosphere-auroral cavity boundary have been studied as a function of cold ionospheric electron temperature and density. The simulations are performed with an open boundary one-dimensional particle-in- cell (PIC) simulation and are initialized by imposing a density cavity within the simulation domain. The PIC simulation includes H{sup +} and O{sup +} ion beams, a hot H{sup +} background population, cold ionospheric electrons, and a hot electron population. It is shown that a double layer remains quasistable for a variety of initial conditions and plasma parameters. The average potential drop of the double layer is found to increase as the cold electron temperature decreases. However, in terms of cold electron density, the average potential drop of the double layer is found to increase up to some critical cold electron density and decreases above this value. Comparisons with FAST observations are made and agreement is found between simulation results and observations in the shape and width of the double layer. This study helps put a constraint on the plasma conditions in which a DL can be expected to form and remain quasistable.

  9. The Announcement Layer: Beacon Coordination for the Sensornet Stack

    E-Print Network [OSTI]

    Dunkels, Adam

    consumption. #12;MAC / Link layers ... ... Multiple, uncoordinated beacons Collect Trickle Deluge Collect Trickle Deluge Coordinated beacons Announcement layer MAC / Link layers Fig. 1. The announcement layer

  10. 12th AIAA/CEAS Aeroacoustics Conference, May 8--10, 2006, Cambridge, Massachusetts PML absorbing boundary condition for non-linear

    E-Print Network [OSTI]

    Hu, Fang Q.

    Perfectly Matched Layer (PML) absorbing boundary condition for the compressible non- linear Navier a viscous flow over a circular cylinder are presented. Satisfactory results demonstrated that the proposed that the absorbing zone is theoretically reflectionless for multi-dimensional linear waves of any angle and frequency

  11. New Boundaries | Issue 16 | June 2013 Treatmentandsupport

    E-Print Network [OSTI]

    Anderson, Jim

    treatments for cancer, for both adults and children, and how we influence healthcare policy to improve|UniversityofSouthampton 5 #12;NewBoundaries|June2013|UniversityofSouthampton6 Cancer treatments researched challenging issues facing society today, from the global need for sustainable energy to innovative treatments

  12. Neumann Conditions on Fractal Boundaries Yves Achdou

    E-Print Network [OSTI]

    Achdou, Yves

    is part of a wider project aimed at simulating the diffusion of medical sprays in lungs. Since the exchanges between the lungs and the circulatory system take place only in the last generations a nonhomogeneous Neumann or Robin condition on the top boundary . Similarly, the lungs are mechanically coupled

  13. The Importance of Carbon Footprint Estimation Boundaries

    E-Print Network [OSTI]

    Kammen, Daniel M.

    The Importance of Carbon Footprint Estimation Boundaries H . S C O T T M A T T H E W S , C H R I and organizations are pursuing "carbon footprint" projects to estimate their own contributions to global climate change. Protocol definitions from carbon registries help organizations analyze their footprints

  14. TRACKING DYNAMIC BOUNDARIES BY EVOLVING Tingting Jiang

    E-Print Network [OSTI]

    Tingting Jiang

    range of applications. An example in image processing is the analysis of image sequences taken might track the boundary of a forest fire. Other applications include tracking spills of oil or poisonous gas, or clouds and weather patterns. In this dissertation, the author describes a new tracking

  15. Layered architecture for quantum computing

    E-Print Network [OSTI]

    N. Cody Jones; Rodney Van Meter; Austin G. Fowler; Peter L. McMahon; Jungsang Kim; Thaddeus D. Ladd; Yoshihisa Yamamoto

    2012-09-27T23:59:59.000Z

    We develop a layered quantum computer architecture, which is a systematic framework for tackling the individual challenges of developing a quantum computer while constructing a cohesive device design. We discuss many of the prominent techniques for implementing circuit-model quantum computing and introduce several new methods, with an emphasis on employing surface code quantum error correction. In doing so, we propose a new quantum computer architecture based on optical control of quantum dots. The timescales of physical hardware operations and logical, error-corrected quantum gates differ by several orders of magnitude. By dividing functionality into layers, we can design and analyze subsystems independently, demonstrating the value of our layered architectural approach. Using this concrete hardware platform, we provide resource analysis for executing fault-tolerant quantum algorithms for integer factoring and quantum simulation, finding that the quantum dot architecture we study could solve such problems on the timescale of days.

  16. Effects of fiber and interfacial layer architectures on the thermoplastic response of metal-matrix composites

    SciTech Connect (OSTI)

    Pindera, M.J.; Freed, A.D.; Arnold, S.M.

    1992-08-01T23:59:59.000Z

    Examined here is the effect of fiber and interfacial layer morphologies on thermal fields in metal matrix composites (MMCs). A micromechanics model based on an arbitrarily layered concentric cylinder configuration is used to calculate thermal stress fields in MMCs subjected to spatially uniform temperature changes. The fiber is modelled as a layered material with isotropic or orthotropic elastic layers, whereas the surrounding matrix, including interfacial layers, is treated as a strain-hardening, elastoplastic, von Mises solid with temperature-dependent parameters. The solution to the boundary-value problem of an arbitrarily layered concentric cylinder under the prescribed thermal loading is obtained using the local/global stiffness matrix formulation originally developed for stress analysis of multilayered elastic media. Examples are provided that illustrate how the morphology of the SCS6 silicon carbide fiber and the use of multiple compliant layers at the fiber/matrix interface affect the evolution of residual stresses in SiC/Ti composites during fabrication cool-down.

  17. Layered Manufacturing Sara McMains

    E-Print Network [OSTI]

    McMains, Sara

    ­ Sintering (vector) ­ 3D Printing (raster) #12;Stereolithography (SLA) · First commercial layered

  18. Process architectures using MeV implanted blanket buried layers for latch-up improvements on bulk silicon

    SciTech Connect (OSTI)

    Rubin, L.M.; Simonton, R.B.; Wilson, S.D. [Eaton Corporation, Beverly, MA (United States); Morris, W. [Silicon Engineering, Austin, TX (United States)

    1996-12-31T23:59:59.000Z

    Doped buried layers formed by MeV ion implantation are attractive alternatives to expensive epitaxial substrates for controlling latch-up in CMOS devices. Two different process architecture approaches for forming effective buried layers are discussed. P+ Around Boundary (PAB), and a more recent derivative, BILLI are compared to a Buried Layer/Connecting Layer (BUCL) architecture, with regards to latch-up resistance, process flexibility, and future scalability. While both architectures have been shown to increase latch-up trigger current on bulk silicon, the BUCL process provides greater latch-up control and process/device flexibility. Process and device simulations as well as experimental data indicate that a properly chosen set of implants for both n-well, p-well, and buried layer structures can yield latch-up isolation superior to 3mm epi.

  19. Integrable Boundaries, Conformal Boundary Conditions and A-D-E Fusion Rules

    E-Print Network [OSTI]

    Roger E. Behrend; Paul A. Pearce; Jean-Bernard Zuber

    1998-07-20T23:59:59.000Z

    The $sl(2)$ minimal theories are labelled by a Lie algebra pair $(A,G)$ where $G$ is of $A$-$D$-$E$ type. For these theories on a cylinder we conjecture a complete set of conformal boundary conditions labelled by the nodes of the tensor product graph $A\\otimes G$. The cylinder partition functions are given by fusion rules arising from the graph fusion algebra of $A\\otimes G$. We further conjecture that, for each conformal boundary condition, an integrable boundary condition exists as a solution of the boundary Yang-Baxter equation for the associated lattice model. The theory is illustrated using the $(A_4,D_4)$ or 3-state Potts model.

  20. Stick-Slip Control in Nanoscale Boundary Lubrication by Surface Wettability

    E-Print Network [OSTI]

    Wei Chen; Adam S. Foster; Mikko J. Alava; Lasse Laurson

    2015-02-13T23:59:59.000Z

    We study the effect of atomic scale surface-lubricant interactions on nanoscale boundary-lubricated friction, by considering two example surfaces - hydrophilic mica and hydrophobic graphene - confining thin layers of water in molecular dynamics simulations. We observe stick-slip dynamics for thin water films confined by mica sheets, involving periodic breaking-reforming transitions of atomic scale capillary water bridges formed around the potassium ions of mica. However, only smooth sliding without stick-slip events is observed for water confined by graphene, as well as for thicker water layers confined by mica. Thus, our results illustrate how atomic scale details affect the wettability of the confining surfaces, and consequently control the presence or absence of stick-slip dynamics in nanoscale friction.

  1. Buffer layer for thin film structures

    DOE Patents [OSTI]

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2010-06-15T23:59:59.000Z

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  2. Buffer layer for thin film structures

    DOE Patents [OSTI]

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2006-10-31T23:59:59.000Z

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  3. Chemical solution seed layer for rabits tapes

    SciTech Connect (OSTI)

    Goyal, Amit; Paranthaman, Mariappan; Wee, Sung-Hun

    2014-06-10T23:59:59.000Z

    A method for making a superconducting article includes the steps of providing a biaxially textured substrate. A seed layer is then deposited. The seed layer includes a double perovskite of the formula A.sub.2B'B''O.sub.6, where A is rare earth or alkaline earth metal and B' and B'' are different rare earth or transition metal cations. A superconductor layer is grown epitaxially such that the superconductor layer is supported by the seed layer.

  4. The relationship between grain boundary structure, defect mobility, and grain boundary sink efficiency

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

    Uberuaga, Blas Pedro; Vernon, Louis J.; Martinez, Enrique; Voter, Arthur F.

    2015-03-13T23:59:59.000Z

    Nanocrystalline materials have received great attention due to their potential for improved functionality and have been proposed for extreme environments where the interfaces are expected to promote radiation tolerance. However, the precise role of the interfaces in modifying defect behavior is unclear. Using long-time simulations methods, we determine the mobility of defects and defect clusters at grain boundaries in Cu. We find that mobilities vary significantly with boundary structure and cluster size, with larger clusters exhibiting reduced mobility, and that interface sink efficiency depends on the kinetics of defects within the interface via the in-boundary annihilation rate of defects. Thus,more »sink efficiency is a strong function of defect mobility, which depends on boundary structure, a property that evolves with time. Further, defect mobility at boundaries can be slower than in the bulk, which has general implications for the properties of polycrystalline materials. Finally, we correlate defect energetics with the volumes of atomic sites at the boundary.« less

  5. Accelerated boundary integral method for multiphase flow in non-periodic geometries

    E-Print Network [OSTI]

    Amit Kumar; Michael D. Graham

    2012-06-05T23:59:59.000Z

    An accelerated boundary integral method for Stokes flow of a suspension of deformable particles is presented for an arbitrary domain and implemented for the important case of a planar slit geometry. The computational complexity of the algorithm scales as O(N) or $O(N\\log N$), where $N$ is proportional to the product of number of particles and the number of elements employed to discretize the particle. This technique is enabled by the use of an alternative boundary integral formulation in which the velocity field is expressed in terms of a single layer integral alone, even in problems with non-matched viscosities. The density of the single layer integral is obtained from a Fredholm integral equation of the second kind involving the double layer integral. Acceleration in this implementation is provided by the use of General Geometry Ewald-like method (GGEM) for computing the velocity and stress fields driven by a set of point forces in the geometry of interest. For the particular case of the slit geometry, a Fourier-Chebyshev spectral discretization of GGEM is developed. Efficient implementations employing the GGEM methodology are presented for the resulting single and the double layer integrals. The implementation is validated with test problems on the velocity of rigid particles and drops between parallel walls in pressure driven flow, the Taylor deformation parameter of capsules in simple shear flow and the particle trajectory in pair collisions of capsules in shear flow. The computational complexity of the algorithm is verified with results from several large scale multiparticle simulations.

  6. Cylinder kernel expansion of Casimir energy with a Robin boundary

    E-Print Network [OSTI]

    Liu, Zhonghai

    2006-10-30T23:59:59.000Z

    We compute the Casimir energy of a massless scalar field obeying the Robin boundary condition on one plate and the Dirichlet boundary condition on another plate for two parallel plates with a separation of alpha. The Casimir energy densities...

  7. Cylinder kernel expansion of Casimir energy with a Robin boundary 

    E-Print Network [OSTI]

    Liu, Zhonghai

    2006-10-30T23:59:59.000Z

    We compute the Casimir energy of a massless scalar field obeying the Robin boundary condition on one plate and the Dirichlet boundary condition on another plate for two parallel plates with a separation of alpha. The ...

  8. Thermodynamic stability and implications of anisotropic boundary particles

    E-Print Network [OSTI]

    Siem, Ellen J. (Ellen Jane), 1979-

    2005-01-01T23:59:59.000Z

    (cont.) Generally, a boundary is nonplanar in the neighborhood of an attached particle--even when anisotropic interfacial free energies do not produce faceting-and maintains a icKy = 0 while the boundary particles maintain ...

  9. Nuclear Power Plant Containment Pressure Boundary Research

    SciTech Connect (OSTI)

    Cherry, J.L.; Chokshi, N.C.; Costello, J.F.; Ellingwood, B.R.; Naus, D.J.

    1999-09-15T23:59:59.000Z

    Research to address aging of the containment pressure boundary in light-water reactor plants is summarized. This research is aimed at understanding the significant factors relating occurrence of corrosion, efficacy of inspection, and structural capacity reduction of steel containment and liners of concrete containment. This understanding will lead to improvements in risk-informed regulatory decision making. Containment pressure boundary components are described and potential aging factors identified. Quantitative tools for condition assessments of aging structures to maintain an acceptable level of reliability over the service life of the plant are discussed. Finally, the impact of aging (i.e., loss of shell thickness due to corrosion) on steel containment fragility for a pressurized water reactor ice-condenser plant is presented.

  10. Open Boundary Conditions for Dissipative MHD

    SciTech Connect (OSTI)

    Meier, E T

    2011-11-10T23:59:59.000Z

    In modeling magnetic confinement, astrophysics, and plasma propulsion, representing the entire physical domain is often difficult or impossible, and artificial, or 'open' boundaries are appropriate. A novel open boundary condition (BC) for dissipative MHD, called Lacuna-based open BC (LOBC), is presented. LOBC, based on the idea of lacuna-based truncation originally presented by V.S. Ryaben'kii and S.V. Tsynkov, provide truncation with low numerical noise and minimal reflections. For hyperbolic systems, characteristic-based BC (CBC) exist for separating the solution into outgoing and incoming parts. In the hyperbolic-parabolic dissipative MHD system, such separation is not possible, and CBC are numerically unstable. LOBC are applied in dissipative MHD test problems including a translating FRC, and coaxial-electrode plasma acceleration. Solution quality is compared to solutions using CBC and zero-normal derivative BC. LOBC are a promising new open BC option for dissipative MHD.

  11. Mineralogical effects on the detectability of the postperovskite boundary

    E-Print Network [OSTI]

    Rhoads, James

    Mineralogical effects on the detectability of the postperovskite boundary Brent Grocholskia,1 discontinuity to the Pv - pPv boundary in pyrolite (homogenized mantle composition). Furthermore, the mineralogy have a detectable Pv - pPv boundary due to their distinct mineralogy. Therefore, the observation

  12. ANNIVERSARY REVIEW Grain boundary energy anisotropy: a review

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    energy (B) gained when the two surfaces are brought together and new bonds are formed. The grain boundaryANNIVERSARY REVIEW Grain boundary energy anisotropy: a review Gregory S. Rohrer Received: 29 April 2011 Abstract This paper reviews findings on the anisotropy of the grain boundary energies. After

  13. CHARACTERIZATION OF PD IMPURITIES AND TWIN BOUNDARY DEFECTS IN DETECTOR GRADE CDZNTE CRYSTALS

    SciTech Connect (OSTI)

    Duff, M.

    2011-06-22T23:59:59.000Z

    Synthetic CdZnTe or ''CZT'' crystals are highly suitable for {gamma}-spectrometers operating at the room temperature. Secondary phases (SP) in CZT are known to inhibit detector performance, particularly when they are present in large numbers or dimensions. These SP may exist as voids or composites of non-cubic phase metallic Te layers with bodies of polycrystalline and amorphous CZT material and voids. Defects associated with crystal twining may also influence detector performance in CZT. Using transmission electron microscopy, we identify two types of defects that are on the nano scale. The first defect consists of 40 nm diameter metallic Pd/Te bodies on the grain boundaries of Te-rich composites. Although the nano-Pd/Te bodies around these composites may be unique to the growth source of this CZT material, noble metal impurities like these may contribute to SP formation in CZT. The second defect type consists of atom-scale grain boundary dislocations. Specifically, these involve inclined ''finite-sized'' planar defects or interfaces between layers of atoms that are associated with twins. Finite-sized twins may be responsible for the subtle but observable striations that can be seen with optical birefringence imaging and synchrotron X-ray topographic imaging.

  14. Invariance properties of boundary sets of open embeddings of manifolds and their application to the abstract boundary

    E-Print Network [OSTI]

    Christopher J. Fama; Susan M. Scott

    1994-06-21T23:59:59.000Z

    The {\\em abstract boundary\\/} (or {\\em {\\em a\\/}-boundary\\/}) of Scott and Szekeres \\cite{Scott94} constitutes a ``boundary'' to any $n$-dimensional, paracompact, connected, Hausdorff, $C^\\infty$-manifold (without a boundary in the usual sense). In general relativity one deals with a {\\em space-% time\\/} $(\\cM,g)$ (a 4-dimensional manifold $\\cM$ with a Lorentzian metric $g$), together with a chosen preferred class of curves in $\\cM$. In this case the {\\em a\\/}-boundary points may represent ``singularities'' or ``points at infinity''. Since the {\\em a\\/}-boundary itself, however, does not depend on the existence of further structure on the manifold such as a Lorentzian metric or connection, it is possible for it to be used in many contexts. In this paper we develop some purely topological properties of abstract boundary sets and abstract boundary points ({\\em a\\/}-boundary points). We prove, amongst other things, that compactness is invariant under boundary set equivalence, and introduce another invariant concept ({\\em isolation\\/}), which encapsulates the notion that a boundary set is ``separated'' from other boundary points of the same embedding. ....... [The abstract continues in paper proper - truncated to fit here.

  15. Harmonic initial-boundary evolution in general relativity

    SciTech Connect (OSTI)

    Babiuc, Maria C. [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Szilagyi, Bela [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, 14476 Golm (Germany); Winicour, Jeffrey [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, 14476 Golm (Germany)

    2006-03-15T23:59:59.000Z

    Computational techniques which establish the stability of an evolution-boundary algorithm for a model wave equation with shift are incorporated into a well-posed version of the initial-boundary value problem for gravitational theory in harmonic coordinates. The resulting algorithm is implemented as a 3-dimensional numerical code which we demonstrate to provide stable, convergent Cauchy evolution in gauge wave and shifted gauge wave testbeds. Code performance is compared for Dirichlet, Neumann, and Sommerfeld boundary conditions and for boundary conditions which explicitly incorporate constraint preservation. The results are used to assess strategies for obtaining physically realistic boundary data by means of Cauchy-characteristic matching.

  16. Harmonic Initial-Boundary Evolution in General Relativity

    E-Print Network [OSTI]

    Maria C. Babiuc; Bela Szilagyi; Jeffrey Winicour

    2006-03-14T23:59:59.000Z

    Computational techniques which establish the stability of an evolution-boundary algorithm for a model wave equation with shift are incorporated into a well-posed version of the initial-boundary value problem for gravitational theory in harmonic coordinates. The resulting algorithm is implemented as a 3-dimensional numerical code which we demonstrate to provide stable, convergent Cauchy evolution in gauge wave and shifted gauge wave testbeds. Code performance is compared for Dirichlet, Neumann and Sommerfeld boundary conditions and for boundary conditions which explicitly incorporate constraint preservation. The results are used to assess strategies for obtaining physically realistic boundary data by means of Cauchy-characteristic matching.

  17. Reconstruction of an unknown cavity with Robin boundary condition inside a heat conductor

    E-Print Network [OSTI]

    Gen Nakamura; Haibing Wang

    2015-05-22T23:59:59.000Z

    Active thermography is a non-destructive testing technique to detect the internal structure of a heat conductor, which is widely applied in industrial engineering. In this paper, we consider the problem of identifying an unknown cavity with Robin boundary condition inside a heat conductor from boundary measurements. To set up the inverse problem mathematically, we first state the corresponding forward problem and show its well-posedness in an anisotropic Sobolev space by the integral equation method. Then, taking the Neumann-to-Dirichlet map as mathematically idealized measured data for the active thermography, we present a linear sampling method for reconstructing the unknown Robin-type cavity and give its mathematical justification by using the layer potential argument. In addition, we analyze the indicator function used in this method and show its pointwise asymptotic behavior by investigating the reflected solution of the fundamental solution. From our asymptotic analysis, we can establish a pointwise reconstruction scheme for the boundary of the cavity, and can also know the distance to the unknown cavity as we probe it from its inside.

  18. Electronic transport in atomically thin layered materials

    E-Print Network [OSTI]

    Baugher, Britton William Herbert

    2014-01-01T23:59:59.000Z

    Electronic transport in atomically thin layered materials has been a burgeoning field of study since the discovery of isolated single layer graphene in 2004. Graphene, a semi-metal, has a unique gapless Dirac-like band ...

  19. Physical layer model design for wireless networks 

    E-Print Network [OSTI]

    Yu, Yi

    2009-06-02T23:59:59.000Z

    the relationship between wireless protocol design and physical layer models, it is necessary to first comprehend the network architecture, which groups the communication functions into related and manageable layers. The journal model is IEEE Transactions... data to the network format and vice versa. It is intended to provide independence from different represen- tations of application layer data. The session layer deals with sessions and connections between applications. It manages conversations between...

  20. Plasma waves reflection from a boundary with specular accommodative boundary conditions

    E-Print Network [OSTI]

    N. V. Gritsienko; A. V. Latyshev; A. A. Yushkanov

    2010-01-06T23:59:59.000Z

    In the present work the linearized problem of plasma wave reflection from a boundary of a half--space is solved analytically. Specular accommodative conditions of plasma wave reflection from plasma boundary are taken into consideration. Wave reflectance is found as function of the given parameters of the problem, and its dependence on the normal electron momentum accommodation coefficient is shown by the authors. The case of resonance when the frequency of self-consistent electric field oscillations is close to the proper (Langmuir) plasma oscillations frequency, namely, the case of long wave limit is analyzed. Refs. 17. Figs. 6.

  1. Convection induced by radiative cooling of a layer of participating medium

    SciTech Connect (OSTI)

    Prasanna, Swaminathan, E-mail: prasannaswam@gmail.com [Laboratoire EM2C, CNRS UPR 288 92295, Chatenay-Malabry, France and Ecole Centrale Paris, Grande Voie des Vignes 92295, Chatenay-Malabry (France)] [Laboratoire EM2C, CNRS UPR 288 92295, Chatenay-Malabry, France and Ecole Centrale Paris, Grande Voie des Vignes 92295, Chatenay-Malabry (France); Venkateshan, S. P., E-mail: spv@iitm.ac.in [HTTP Laboratory, Department of Mechanical Engineering IIT Madras, Chennai (India)

    2014-05-15T23:59:59.000Z

    Simulations and experiments have been conducted to study the effect of radiative cooling on natural convection in a horizontal layer of a participating medium enclosed between isothermal opaque wall and radiatively transparent wall and exposed to a cold background. The study is of relevance to a nocturnal boundary layer under clear and calm conditions. The focus of the study is to capture the onset of convection caused by radiative cooling. The experiments have been designed to mimic the atmospheric radiative boundary conditions, and hence decoupling convection and radiation boundary conditions. Planck number Pl and optical thickness of the layer ?{sub H} are the two important parameters that govern the interaction between radiation and convection. The radiation-convection coupling is a strong function of length scale. Convection sets up within first few seconds for all the experiments. Strong plume like convection is observed for the experimental conditions used in the present study. Both simulations and experiments confirm that radiative cooling increases substantially with decrease in emissivity of the bottom wall. Radiative cooling is strongly influenced by the nongray nature of the participating medium, especially when strong emission from the medium escapes to space, in the window region of the atmosphere. Accurate representation of radiative properties is critical. Linear stability analysis of onset of convection indicates that radiation stabilizes convection as Pl decreases. The observations are similar to the case of Rayleigh Bénard convection in a radiating gas. However, for both experimental and numerical conditions, the observed Rayleigh numbers are much greater than the critical Rayleigh number. To conclude, the role of radiation is to drive and sustain convection in the unstable layer.

  2. Soil moisture in complex terrain: quantifying effects on atmospheric boundary layer flow and providing improved surface boundary conditions for mesoscale models

    E-Print Network [OSTI]

    Daniels, Megan Hanako

    2010-01-01T23:59:59.000Z

    74 ii Soil Moisture Sensors: Decagon ECH2O Capacitance133 A.10 Soil types corresponding to each75 Soil Moisture and Temperature Probe

  3. Soil moisture in complex terrain: quantifying effects on atmospheric boundary layer flow and providing improved surface boundary conditions for mesoscale models

    E-Print Network [OSTI]

    Daniels, Megan Hanako

    2010-01-01T23:59:59.000Z

    red indicates “water towers” generated by kinematic wavethe kinematic wave equation will begin to collect water onred indicates “water towers” generated by kinematic wave

  4. Soil moisture in complex terrain: quantifying effects on atmospheric boundary layer flow and providing improved surface boundary conditions for mesoscale models

    E-Print Network [OSTI]

    Daniels, Megan Hanako

    2010-01-01T23:59:59.000Z

    groundwater, land-surface, and mesoscale atmospheric model-and modification of mesoscale circulations. , Mon. Wea.J. Davis, The effects of mesoscale surface heterogeneity on

  5. Soil moisture in complex terrain: quantifying effects on atmospheric boundary layer flow and providing improved surface boundary conditions for mesoscale models

    E-Print Network [OSTI]

    Daniels, Megan Hanako

    2010-01-01T23:59:59.000Z

    direction, (b) wind speed, (c) potential temperature, and (Airport of potential temperature, wind speed, winderrors (bias) for potential temperature, wind speed, wind

  6. Microfluidics: The no-slip boundary condition

    E-Print Network [OSTI]

    Eric Lauga; Michael P. Brenner; Howard A. Stone

    2005-09-28T23:59:59.000Z

    The no-slip boundary condition at a solid-liquid interface is at the center of our understanding of fluid mechanics. However, this condition is an assumption that cannot be derived from first principles and could, in theory, be violated. We present a review of recent experimental, numerical and theoretical investigations on the subject. The physical picture that emerges is that of a complex behavior at a liquid/solid interface, involving an interplay of many physico-chemical parameters, including wetting, shear rate, pressure, surface charge, surface roughness, impurities and dissolved gas.

  7. Enhanced molecular dynamics for simulating porous interphase layers in batteries.

    SciTech Connect (OSTI)

    Zimmerman, Jonathan A.; Wong, Bryan Matthew; Jones, Reese E.; Templeton, Jeremy Alan; Lee, Jonathan (Rice University, Houston, TX)

    2009-10-01T23:59:59.000Z

    Understanding charge transport processes at a molecular level using computational techniques is currently hindered by a lack of appropriate models for incorporating anistropic electric fields in molecular dynamics (MD) simulations. An important technological example is ion transport through solid-electrolyte interphase (SEI) layers that form in many common types of batteries. These layers regulate the rate at which electro-chemical reactions occur, affecting power, safety, and reliability. In this work, we develop a model for incorporating electric fields in MD using an atomistic-to-continuum framework. This framework provides the mathematical and algorithmic infrastructure to couple finite element (FE) representations of continuous data with atomic data. In this application, the electric potential is represented on a FE mesh and is calculated from a Poisson equation with source terms determined by the distribution of the atomic charges. Boundary conditions can be imposed naturally using the FE description of the potential, which then propagates to each atom through modified forces. The method is verified using simulations where analytical or theoretical solutions are known. Calculations of salt water solutions in complex domains are performed to understand how ions are attracted to charged surfaces in the presence of electric fields and interfering media.

  8. Layer-by-Layer Characterization of a Model Biofuel Cell Anode by (in Situ) Vibrational Spectroscopy

    E-Print Network [OSTI]

    Brolo, Alexandre G.

    Layer-by-Layer Characterization of a Model Biofuel Cell Anode by (in Situ) Vibrational Spectroscopy during the construction of a model biofuel cell anode. The model anode was a layered structure formedDH to the CB layer confirmed successful enzyme immobilization. 1. Introduction Biofuel cells use microorganisms

  9. Dense, layered membranes for hydrogen separation

    DOE Patents [OSTI]

    Roark, Shane E.; MacKay, Richard; Mundschau, Michael V.

    2006-02-21T23:59:59.000Z

    This invention provides hydrogen-permeable membranes for separation of hydrogen from hydrogen-containing gases. The membranes are multi-layer having a central hydrogen-permeable layer with one or more catalyst layers, barrier layers, and/or protective layers. The invention also relates to membrane reactors employing the hydrogen-permeable membranes of the invention and to methods for separation of hydrogen from a hydrogen-containing gas using the membranes and reactors. The reactors of this invention can be combined with additional reactor systems for direct use of the separated hydrogen.

  10. Supergravity at the boundary of AdS supergravity

    SciTech Connect (OSTI)

    Amsel, Aaron J.; Compere, Geoffrey [Department of Physics, University of California, Santa Barbara, California 93106 (United States)

    2009-04-15T23:59:59.000Z

    We give a general analysis of AdS boundary conditions for spin-3/2 Rarita-Schwinger fields and investigate boundary conditions preserving supersymmetry for a graviton multiplet in AdS{sub 4}. Linear Rarita-Schwinger fields in AdS{sub d} are shown to admit mixed Dirichlet-Neumann boundary conditions when their mass is in the range 0{<=}|m|<1/2l{sub AdS}. We also demonstrate that mixed boundary conditions are allowed for larger masses when the inner product is 'renormalized' accordingly with the action. We then use the results obtained for |m|=1/l{sub AdS} to explore supersymmetric boundary conditions for N=1 AdS{sub 4} supergravity in which the metric and Rarita-Schwinger fields are fluctuating at the boundary. We classify boundary conditions that preserve boundary supersymmetry or superconformal symmetry. Under the AdS/CFT dictionary, Neumann boundary conditions in d=4 supergravity correspond to gauging the superconformal group of the three-dimensional CFT describing M2-branes, while N=1 supersymmetric mixed boundary conditions couple the CFT to N=1 superconformal topologically massive gravity.

  11. Water Vapor Turbulence Profiles in Stationary Continental Convective Mixed Layers

    SciTech Connect (OSTI)

    Turner, D. D.; Wulfmeyer, Volker; Berg, Larry K.; Schween, Jan

    2014-10-08T23:59:59.000Z

    The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program’s Raman lidar at the ARM Southern Great Plains (SGP) site in north-central Oklahoma has collected water vapor mixing ratio (q) profile data more than 90% of the time since October 2004. Three hundred (300) cases were identified where the convective boundary layer was quasi-stationary and well-mixed for a 2-hour period, and q mean, variance, third order moment, and skewness profiles were derived from the 10-s, 75-m resolution data. These cases span the entire calendar year, and demonstrate that the q variance profiles at the mixed layer (ML) top changes seasonally, but is more related to the gradient of q across the interfacial layer. The q variance at the top of the ML shows only weak correlations (r < 0.3) with sensible heat flux, Deardorff convective velocity scale, and turbulence kinetic energy measured at the surface. The median q skewness profile is most negative at 0.85 zi, zero at approximately zi, and positive above zi, where zi is the depth of the convective ML. The spread in the q skewness profiles is smallest between 0.95 zi and zi. The q skewness at altitudes between 0.6 zi and 1.2 zi is correlated with the magnitude of the q variance at zi, with increasingly negative values of skewness observed lower down in the ML as the variance at zi increases, suggesting that in cases with larger variance at zi there is deeper penetration of the warm, dry free tropospheric air into the ML.

  12. Fission Product Transport in TRISO Particle Layers under Operating and Off-Normal Conditions

    SciTech Connect (OSTI)

    Van der Ven, Anton; Was, Gary; Wang, Lumin; Taheri, Mitra

    2014-07-07T23:59:59.000Z

    The objective of this project is to determine the diffusivity and chemical behavior of key fission products (ag, Cs, I. Te, Eu and Sr) through SiC and PyC both thermally, under irradiation, and under stress using FP introduction techniques that avoid the pitfalls of past experiments. The experimental approach is to create thin PyC-SiC couples containing the fission product to be studied embedded in the PyC layer. These samples will then be subjected to high temperature exposures in a vacuum and also to irradiation at high temperature, and last, to irradiation under stress at high temperature. The PyC serves as a host layer, providing a means of placing the fission product close to the SiC without damaging the SiC layer by its introduction or losing the FP during heating. Experimental measurements of grain boundary structure and distribution (EBSD, HRTEM, APT) will be used in the modeling effort to determine the qualitative dependence of FP diffusion coefficients on grain boundary orientation, temperature and stress.

  13. Simulation of MLI concerning the influence of an additional heat load on intermediate layers

    SciTech Connect (OSTI)

    Funke, Thomas; Golle, Steffen; Haberstroh, Christoph [Technische Universitaet Dresden, Bitzer-Stiftungsprofessur fuer Kaelte-, Kryo- und Kompressorentechnik, Dresden, 01062 (Germany)

    2014-01-29T23:59:59.000Z

    Multilayer insulation (MLI) is commonly used in most cryogenic devices such as LHe cryostats or storage vessels. Numerical and experimental studies of such insulation systems are known from literature. The temperature distribution of intermediate layers has been investigated as well. Experiments using temperature sensors, for example thermocouples, to determine the temperature of intermediate layers had been described. Naturally such wiring causes additional heat load on the respective layer and influences the equilibrium temperature. A mathematical model of heat transfer through MLI has been developed to investigate the temperature distribution across the MLI layers. The model comprises a combination of radiation, residual gas conduction and conductive heat flux. An analysis for variable cold and warm boundary temperatures and various residual gases and pressures is carried out. In addition to the model an experimental test rig will be built for the verification of the model. The paper presents the influence of an additional heat load on an intermediate layer on the temperature distribution and on the overall thermal performance of MLI.

  14. An outflow boundary condition and algorithm for incompressible two ...

    E-Print Network [OSTI]

    S. Dong

    2014-03-05T23:59:59.000Z

    Feb 22, 2014 ... [8] S. Dong, G.E. Karniadakis, C. Chryssostomidis, A robust and accurate outflow boundary condition for incompressible flow simulations on ...

  15. an inverse boundary value problem for the stationary transport ...

    E-Print Network [OSTI]

    outer normal to ?X at x ? ?X. Let us denote by f the solution (if exists) to the following boundary value problem for the stationary linear transport (Boltzmann)

  16. absorbing boundary condition: Topics by E-print Network

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

    Summary: Absorbing Boundary Condition, Domain Decomposition and Hydrodynamic Wave Model O. Wilk Introduction. appli. (wave equation) Num. appli. (hydro. wave model)...

  17. antiphase domain boundaries: Topics by E-print Network

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

    Summary: Absorbing Boundary Condition, Domain Decomposition and Hydrodynamic Wave Model O. Wilk Introduction. appli. (wave equation) Num. appli. (hydro. wave model)...

  18. absorbing boundary conditions: Topics by E-print Network

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

    Summary: Absorbing Boundary Condition, Domain Decomposition and Hydrodynamic Wave Model O. Wilk Introduction. appli. (wave equation) Num. appli. (hydro. wave model)...

  19. Existence of solutions to boundary value problems for smectic liquid ...

    E-Print Network [OSTI]

    2009-05-25T23:59:59.000Z

    Existence of solutions to boundary value problems for smectic liquid crys- tals. Abstract. We investigate variational problems for an energy developed by the.

  20. Friction of Steel Sliding Under Boundary Lubrication Regime in...

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

    by reducing parasitic boundary regime friction losses and enable operation with lower viscosity oils while maintaining engine durability. deer08erck.pdf More Documents &...

  1. On deriving nonreflecting boundary conditions in generalized curvilinear coordinates

    E-Print Network [OSTI]

    Adrian Sescu

    2015-01-20T23:59:59.000Z

    In this work, nonreflecting boundary conditions in generalized three-dimensional curvilinear coordinates are derived, relying on the original analysis that was done in Cartesian two-dimensional coordinates by Giles (AIAA Journal, 28.12, 2050-2058, 1990). A thorough Fourier analysis of the linearized Euler equation is performed to determine the eigenvalues and the eigenvectors that are then used to derive the appropriate inflow and outflow boundary conditions. The analysis lacks rigorous proof of the well-posedness in the general case, which is open to investigation (a weak assumption is introduced here to complete the boundary conditions). The boundary conditions derived here are not tested on specific applications.

  2. EA-1973: Kootenai River Restoration at Bonners Ferry, Boundary...

    Energy Savers [EERE]

    Kootenai River Restoration at Bonners Ferry, Boundary County, Idaho Summary Bonneville Power Administration (BPA) is preparing an EA to assess the potential environmental impacts...

  3. Distribution of germanium in Si{sub 1-x}Ge{sub x} (x < 0.1) layers grown on the Si(001) substrate as a function of layer thickness

    SciTech Connect (OSTI)

    Bagaev, V. S.; Krivobok, V. S.; Martovitsky, V. P., E-mail: victormart@yandex.r [Russian Academy of Sciences, P. N. Lebedev Physical Institute (Russian Federation); Novikov, A. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

    2009-12-15T23:59:59.000Z

    The germanium distribution in Si(001)/Si{sub 1-x}Ge{sub x} layers as a function of the layer thickness at a low dopant concentration (x < 6%) has been investigated using high-resolution X-ray diffractometry and low-temperature photoluminescence. It has been shown that the germanium concentration increases with increasing thickness of the SiGe layer with the formation of lateral inhomogeneities at the boundary between this layer and a silicon cap layer for a layer thickness of 30 nm or more. These inhomogeneities have an oriented character and give rise to anisotropic diffuse scattering for the system of (113) and (224) asymmetric reflections from SiGe. The luminescence of these films at low temperatures and low excitation densities is an emission of localized and delocalized excitons, which is characteristic of systems with disorder. The revealed nonuniform germanium distribution in the lateral direction is associated with the accumulation of germanium in the near-surface SiGe layer and with the partial relaxation of elastic strains due to the development of surface roughness and the preferred incorporation of germanium atoms into one side of the surface ripples.

  4. Double layer formation in the expanding region of an inductively coupled electronegative plasma

    E-Print Network [OSTI]

    Plihon, N; Chabert, P

    2015-01-01T23:59:59.000Z

    Double-layers (DLs) were observed in the expanding region of an inductively coupled plasma with $\\text{Ar}/\\text{SF}\\_6$ gas mixtures. No DL was observed in pure argon or $\\text{SF}\\_6$ fractions below few percent. They exist over a wide range of power and pressure although they are only stable for a small window of electronegativity (typically between 8\\% and 13\\% of $\\text{SF}\\_6$ at 1mTorr), becoming unstable at higher electronegativity. They seem to be formed at the boundary between the source tube and the diffusion chamber and act as an internal boundary (the amplitude being roughly 1.5$\\frac{kT\\_e}{e}$)between a high electron density, high electron temperature, low electronegativity plasma upstream (in the source), and a low electron density, low electron temperature, high electronegativity plasma downstream.

  5. Combustion fronts in porous media with two layers Steve Schecter

    E-Print Network [OSTI]

    Schecter, Stephen

    Combustion fronts in porous media with two layers layer 1 layer 2 Steve Schecter North Carolina Subject: Propagation of a combustion front through a porous medium with two parallel layers having different properties. · Each layer admits a traveling combustion wave. · The layers are coupled by heat

  6. Method to fabricate layered material compositions

    DOE Patents [OSTI]

    Fleming, James G. (Albuquerque, NM); Lin, Shawn-Yu (Albuquerque, NM)

    2002-01-01T23:59:59.000Z

    A new class of processes suited to the fabrication of layered material compositions is disclosed. Layered material compositions are typically three-dimensional structures which can be decomposed into a stack of structured layers. The best known examples are the photonic lattices. The present invention combines the characteristic features of photolithography and chemical-mechanical polishing to permit the direct and facile fabrication of, e.g., photonic lattices having photonic bandgaps in the 0.1-20.mu. spectral range.

  7. Method to fabricate layered material compositions

    DOE Patents [OSTI]

    Fleming, James G.; Lin, Shawn-Yu

    2004-11-02T23:59:59.000Z

    A new class of processes suited to the fabrication of layered material compositions is disclosed. Layered material compositions are typically three-dimensional structures which can be decomposed into a stack of structured layers. The best known examples are the photonic lattices. The present invention combines the characteristic features of photolithography and chemical-mechanical polishing to permit the direct and facile fabrication of, e.g., photonic lattices having photonic bandgaps in the 0.1-20.mu. spectral range.

  8. Manganese containing layer for magnetic recording media

    DOE Patents [OSTI]

    Lambeth, David N. (Pittsburgh, PA); Lee, Li-Lien (Santa Clara, CA); Laughlin, David E. (Pittsburgh, PA)

    1999-01-01T23:59:59.000Z

    The present invention provides for a magnetic recording media incorporating Mn-containing layers between a substrate and a magnetic layer to provide media having increased coercivity and lower noise. The Mn-containing layer can be incorporated in a rotating, translating or stationary recording media to operate in conjunction with magnetic transducing heads for recording and reading of magnetic data, as well as other applications. The magnetic recording medium of the invention preferably includes a Co or Co alloy film magnetic layer, and Mn-containing layer, preferably comprised of VMn, TiMn, MnZn, CrMnMo, CrMnW, CrMnV, and CrMnTi, and most preferably a CrMn alloy, disposed between the substrate and the magnetic layer to promote an epitaxial crystalline structure in the magnetic layer. The medium can further include seed layers, preferably polycrystalline MgO for longitudinal media, underlayers, and intermediate layers. Underlayers and intermediate layers are comprised of materials having either an A2 structure or a B2-ordered crystalline structure disposed between the seed layer and the magnetic layer. Materials having an A2 structure are preferably Cr or Cr alloys, such as CrV, CrMo, CrW and CrTi. Materials having a B2-ordered structure having a lattice constant that is substantially comparable to that of Cr, such as those preferably selected from the group consisting of NiAl, AILCo, FeAl, FeTi, CoFe, CoTi, CoHf, CoZr, NiTi, CuBe, CuZn, A-LMn, AlRe, AgMg, and Al.sub.2 FeMn.sub.2, and is most preferably FeAl or NiAl.

  9. Sandia National Laboratories: atomic layer deposition

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

    layer deposition Combining 'Tinkertoy' Materials with Solar Cells for Increased Photovoltaic Efficiency On December 4, 2014, in Energy, Materials Science, News, News & Events,...

  10. Enhanced Densification of SDC Barrier Layers

    SciTech Connect (OSTI)

    Hardy, John S.; Templeton, Jared W.; Lu, Zigui; Stevenson, Jeffry W.

    2011-09-12T23:59:59.000Z

    This technical report explores the Enhanced Densification of SCD Barrier Layers A samaria-doped ceria (SDC) barrier layer separates the lanthanum strontium cobalt ferrite (LSCF) cathode from the yttria-stabilized zirconia (YSZ) electrolyte in a solid oxide fuel cell (SOFC) to prevent the formation of electrically resistive interfacial SrZrO{sub 3} layers that arise from the reaction of Sr from the LSCF with Zr from the YSZ. However, the sintering temperature of this SDC layer must be limited to {approx}1200 C to avoid extensive interdiffusion between SDC and YSZ to form a resistive CeO{sub 2}-ZrO{sub 2} solid solution. Therefore, the conventional SDC layer is often porous and therefore not as impervious to Sr-diffusion as would be desired. In the pursuit of improved SOFC performance, efforts have been directed toward increasing the density of the SDC barrier layer without increasing the sintering temperature. The density of the SDC barrier layer can be greatly increased through small amounts of Cu-doping of the SDC powder together with increased solids loading and use of an appropriate binder system in the screen print ink. However, the resulting performance of cells with these barrier layers did not exhibit the expected increase in accordance with that achieved with the prototypical PLD SDC layer. It was determined by XRD that increased sinterability of the SDC also results in increased interdiffusivity between the SDC and YSZ, resulting in formation of a highly resistive solid solution.

  11. Electronic Transport in Few-layer Graphene

    E-Print Network [OSTI]

    Zhao, Zeng

    2013-01-01T23:59:59.000Z

    in Charge Neutral Bilayer Graphene Introduction In thisstudy on heterogeneous graphene devices in a differentto probe few layer graphene to determine their dependence on

  12. Organic photovoltaic cells utilizing ultrathin sensitizing layer

    DOE Patents [OSTI]

    Forrest, Stephen R. (Ann Arbor, MI); Yang, Fan (Piscataway, NJ); Rand, Barry P. (Somers, NY)

    2011-09-06T23:59:59.000Z

    A photosensitive device includes a plurality of organic photoconductive materials disposed in a stack between a first electrode and a second electrode, including a first continuous layer of donor host material, a second continuous layer of acceptor host material, and at least one other organic photoconductive material disposed as a plurality of discontinuous islands between the first continuous layer and the second continuous layer. Each of these other photoconductive materials has an absorption spectra different from the donor host material and the acceptor host material. Preferably, each of the discontinuous islands consists essentially of a crystallite of the respective organic photoconductive material, and more preferably, the crystallites are nanocrystals.

  13. Nanomanufacturing : nano-structured materials made layer-by-layer.

    SciTech Connect (OSTI)

    Cox, James V.; Cheng, Shengfeng; Grest, Gary Stephen; Tjiptowidjojo, Kristianto (University of New Mexico); Reedy, Earl David, Jr.; Fan, Hongyou; Schunk, Peter Randall; Chandross, Michael Evan; Roberts, Scott A.

    2011-10-01T23:59:59.000Z

    Large-scale, high-throughput production of nano-structured materials (i.e. nanomanufacturing) is a strategic area in manufacturing, with markets projected to exceed $1T by 2015. Nanomanufacturing is still in its infancy; process/product developments are costly and only touch on potential opportunities enabled by growing nanoscience discoveries. The greatest promise for high-volume manufacturing lies in age-old coating and imprinting operations. For materials with tailored nm-scale structure, imprinting/embossing must be achieved at high speeds (roll-to-roll) and/or over large areas (batch operation) with feature sizes less than 100 nm. Dispersion coatings with nanoparticles can also tailor structure through self- or directed-assembly. Layering films structured with these processes have tremendous potential for efficient manufacturing of microelectronics, photovoltaics and other topical nano-structured devices. This project is designed to perform the requisite R and D to bring Sandia's technology base in computational mechanics to bear on this scale-up problem. Project focus is enforced by addressing a promising imprinting process currently being commercialized.

  14. Boundary approximate controllability of some linear parabolic April 5, 2013

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Boundary approximate controllability of some linear parabolic systems April 5, 2013 Guillaume Olive controllability of two classes of linear parabolic systems, namely a system of n heat equations coupled through are the only ones concerning the boundary controllability of linear parabolic systems of heat-type. For more

  15. Einstein manifolds with convex boundaries JeanMarc Schlenker \\Lambda

    E-Print Network [OSTI]

    Schlenker, Jean-Marc

    Einstein manifolds with convex boundaries Jean­Marc Schlenker \\Lambda February 2, 1999 Abstract Let (M; @M) be a compact m+1­manifold with boundary with an Einstein metric g 0 , with ric g0 = \\Gammamg metric on @M . Then any metric close enough to h 0 is induced on @M by an Einstein metric g with ric g

  16. Einstein manifolds with convex boundaries Jean-Marc Schlenker*

    E-Print Network [OSTI]

    Schlenker, Jean-Marc

    Einstein manifolds with convex boundaries Jean Let (M, @M) be a compact m+1-manifold with boundary with an Einstein me* *tric g0, with ricg0 be the induced metric on @M. Then any metric close e* *nough to h0 is induced on @M by an Einstein metric g

  17. Riemann surfaces with boundaries and the theory of vertex operator

    E-Print Network [OSTI]

    Huang, Yi-Zhi

    of quantum field theory. When a definition of quantum field theory is given mathematically, a wellRiemann surfaces with boundaries and the theory of vertex operator algebras Yi-Zhi Huang Abstract The connection between Riemann surfaces with boundaries and the theory of vertex operator algebras is discussed

  18. Boundary filters for vector particles passing parity breaking domains

    SciTech Connect (OSTI)

    Kolevatov, S. S.; Andrianov, A. A. [Saint Petersburg State University, 1 ul. Ulyanovskaya, St. Petersburg, 198504 (Russian Federation)

    2014-07-23T23:59:59.000Z

    The electrodynamics supplemented with a Lorenz and CPT invariance violating Chern-Simons (CS) action (Carrol-Field-Jackiw electrodynamics) is studied when the parity-odd medium is bounded by a hyperplane separating it from the vacuum. The solutions in both half-spaces are carefully discussed and for space-like boundary stitched on the boundary with help of the Bogolubov transformations. The presence of two different Fock vacua is shown. The passage of photons and massive vector mesons through a boundary between the CS medium and the vacuum of conventional Maxwell electrodynamics is investigated. Effects of reflection from a boundary (up to the total one) are revealed when vector particles escape to vacuum and income from vacuum passing the boundary.

  19. SHORT-TERM EVOLUTION OF CORONAL HOLE BOUNDARIES

    SciTech Connect (OSTI)

    Krista, Larisza D.; Gallagher, Peter T.; Bloomfield, D. Shaun [Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2 (Ireland)

    2011-04-20T23:59:59.000Z

    The interaction of open and closed field lines at coronal hole (CH) boundaries is widely accepted to be due to interchange magnetic reconnection. To date, it is unclear how the boundaries vary on short timescales and at what velocity this occurs. Here, we describe an automated boundary tracking method used to determine CH boundary displacements on short timescales. The boundary displacements were found to be isotropic and to have typical expansion/contraction speeds of {<=}2 km s{sup -1}, which indicate magnetic reconnection rates of {<=}3 x 10{sup -3}. The observed displacements were used in conjunction with the interchange reconnection model to derive typical diffusion coefficients of {<=}3 x 10{sup 13} cm{sup 2} s{sup -1}. These results are consistent with an interchange reconnection process in the low corona driven by the random granular motions of open and closed fields in the photosphere.

  20. Layer-by-Layer Assembly of a pH-Responsive and Electrochromic Thin Film

    E-Print Network [OSTI]

    Schmidt, Daniel J.

    This article summarizes an experiment on thin-film fabrication with layer-by-layer assembly that is appropriate for undergraduate laboratory courses. The purpose of this experiment is to teach students about self-assembly ...

  1. An ultra-thin buffer layer for Ge epitaxial layers on Si

    SciTech Connect (OSTI)

    Kawano, M.; Yamada, S.; Tanikawa, K.; Miyao, M.; Hamaya, K. [Department of Electronics, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan)] [Department of Electronics, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Sawano, K. [Advanced Research Laboratories, Tokyo City University, 8-15-1 Todoroki, Tokyo 158-0082 (Japan)] [Advanced Research Laboratories, Tokyo City University, 8-15-1 Todoroki, Tokyo 158-0082 (Japan)

    2013-03-25T23:59:59.000Z

    Using an Fe{sub 3}Si insertion layer, we study epitaxial growth of Ge layers on a Si substrate by a low-temperature molecular beam epitaxy technique. When we insert only a 10-nm-thick Fe{sub 3}Si layer in between Si and Ge, epitaxial Ge layers can be obtained on Si. The detailed structural characterizations reveal that a large lattice mismatch of {approx}4% is completely relaxed in the Fe{sub 3}Si layer. This means that the Fe{sub 3}Si layers can become ultra-thin buffer layers for Ge on Si. This method will give a way to realize a universal buffer layer for Ge, GaAs, and related devices on a Si platform.

  2. Surface engineering using layer-by-layer assembly of pH-sensitive polymers and nanoparticles

    E-Print Network [OSTI]

    Lee, Daeyeon

    2007-01-01T23:59:59.000Z

    Surface engineering of a variety of materials including colloidal particles and porous membranes has been achieved by using layer-by-layer assembly of pH-sensitive polymers and nanoparticles. In the first part of this ...

  3. Amperometric Glucose Biosensor by Means of Electrostatic Layer-by-layer Adsorption onto Electrospun Polyaniline Fibers

    E-Print Network [OSTI]

    Shin, Young J.

    2010-07-14T23:59:59.000Z

    were formed and collected by electrospinning. Glucose oxidase was immobilized onto these fibers using an electrostatic layer-by-layer adsorption technique. In this method, poly(diallyldimethylammonium chloride) was used as the counter ion source...

  4. automated spin-assisted layer-by-layer: Topics by E-print Network

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

    Thomas 2005-01-01 16 Layer-by-Layer Assembly of a pH-Responsive and Electrochromic Thin Film MIT - DSpace Summary: This article summarizes an experiment on thin-film fabrication...

  5. Engineering the electrochromism and ion conduction of layer-by-layer assembled films

    E-Print Network [OSTI]

    DeLongchamp, Dean M. (Dean Michael), 1975-

    2003-01-01T23:59:59.000Z

    This work applies the processing technique of layer-by-layer (LBL) assembly to the creation and development of new electrochemically active materials. Elements of the thin-film electrochromic cell were chosen as a particular ...

  6. Antimicrobial Activity of Cationic Antiseptics in Layer-by-Layer Thin Film Assemblies

    E-Print Network [OSTI]

    Dvoracek, Charlene M.

    2010-07-14T23:59:59.000Z

    Layer-by-layer (LbL) assembly has proven to be a powerful technique for assembling thin films with a variety of properties including electrochromic, molecular sensing, oxygen barrier, and antimicrobial. LbL involves the deposition of alternating...

  7. Impact significance determination-Pushing the boundaries

    SciTech Connect (OSTI)

    Lawrence, David P. [P.O. Station A, Box 3475, Langley, B.C., V3A 4R8 (Canada)], E-mail: lawenv@telus.net

    2007-11-15T23:59:59.000Z

    Impact significance determination practice tends to be highly variable. Too often insufficient consideration is given to good practice insights. Also, impact significance determinations are frequently narrowly defined addressing, for example, only individual, negative impacts, focusing on bio-physical impacts, and not seeking to integrate either the Precautionary Principle or sustainability. This article seeks to extend the boundaries of impact significance determination practice by providing an overview of good general impact significance practices, together with stakeholder roles and potential methods for addressing significance determination challenges. Relevant thresholds, criteria, contextual considerations and support methods are also highlighted. The analysis is then extended to address how impact significance determination practices change for positive as compared with negative impacts, for cumulative as compared with individual impacts, for socio-economic as compared with bio-physical impacts, when the Precautionary Principle is integrated into the process, and when sustainability contributions drive the EIA process and related impact significance determinations. These refinements can assist EIA practitioners in ensuring that the scope and nature of impact significance determinations reflect the broadened scope of emerging EIA requirements and practices. Suggestions are included for further refining and testing of the proposed changes to impact significance determination practice.

  8. Calculations of composition boundaries of saturated phases

    SciTech Connect (OSTI)

    Brewer, L.; Hahn, S.

    1983-09-27T23:59:59.000Z

    A program for the HP-41CV calculator is presented for calculating the equilibrium composition boundaries of pairs of saturating solids, liquids, or a combination of a solid and liquid. The activity coefficients must be represented in the form ln ..gamma../sub 1/ = (b/sub h//T - b/sub s/)x/sub 2//sup 2/ + (c/sub h//T - c/sub x/)x/sub 2//sup 3/ where h refers to an enthalpy contribution and s refers to an excess entropy contribution. For solid-liquid equilibria, enthalpies and entropies of fusion are required. For all equilibria, provision is made for use of hypothetical standard states such as the Henry's Law standard states. For example, in treating solid solutions of molybdenum in face-centered cubic metals such as Ni, Rh, or Pt, it is sometimes convenient to use a hypothetical fcc standard state of Mo which represents the limiting Henry's Law behavior of Mo in the fcc metal and has much different properties than a real fcc molybdenum solid.

  9. The Relationship Between Grain Boundary Energy, Grain Boundary Complexion Transitions, and Grain Size in Ca-doped Yttria

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    The Relationship Between Grain Boundary Energy, Grain Boundary Complexion Transitions, and Grain complexions. One idea is that complexion transitions occur to lower the average energy of the interface energy. Experiments on doped aluminas have shown that a complexion transition can change the relative

  10. Steady water waves with multiple critical layers

    E-Print Network [OSTI]

    Mats Ehrnström; Joachim Escher; Erik Wahlén

    2011-04-01T23:59:59.000Z

    We construct small-amplitude periodic water waves with multiple critical layers. In addition to waves with arbitrarily many critical layers and a single crest in each period, two-dimensional sets of waves with several crests and troughs in each period are found. The setting is that of steady two-dimensional finite-depth gravity water waves with vorticity.

  11. Channel cracks in atomic-layer and molecular-layer deposited multilayer thin film coatings

    SciTech Connect (OSTI)

    Long, Rong, E-mail: rlongmech@gmail.com [Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 2G8 (Canada); Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309 (United States); Dunn, Martin L. [Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309 (United States); Singapore University of Technology and Design, Singapore 138682 (Singapore)

    2014-06-21T23:59:59.000Z

    Metal oxide thin film coatings produced by atomic layer deposition have been shown to be an effective permeation barrier. The primary failure mode of such coatings under tensile loads is the propagation of channel cracks that penetrate vertically into the coating films. Recently, multi-layer structures that combine the metal oxide material with relatively soft polymeric layers produced by molecular layer deposition have been proposed to create composite thin films with desired properties, including potentially enhanced resistance to fracture. In this paper, we study the effects of layer geometry and material properties on the critical strain for channel crack propagation in the multi-layer composite films. Using finite element simulations and a thin-film fracture mechanics formalism, we show that if the fracture energy of the polymeric layer is lower than that of the metal oxide layer, the channel crack tends to penetrate through the entire composite film, and dividing the metal oxide and polymeric materials into thinner layers leads to a smaller critical strain. However, if the fracture energy of the polymeric material is high so that cracks only run through the metal oxide layers, more layers can result in a larger critical strain. For intermediate fracture energy of the polymer material, we developed a design map that identifies the optimal structure for given fracture energies and thicknesses of the metal oxide and polymeric layers. These results can facilitate the design of mechanically robust permeation barriers, an important component for the development of flexible electronics.

  12. Experimental development of the predictive relations for the eddy exchange coefficients for momentum and heat in the atmospheric boundary layer

    E-Print Network [OSTI]

    Jensen, Paul Alfred

    1972-01-01T23:59:59.000Z

    . 3 &ii. t' i' 1i~:. . ;at of: t'ai. , : -. . '. ; r. ;. ;. r, ': i r:;. - ~ leer-. . - . :. . . , , . ;: o i r ". pc i' FC:"1;', );, 1')7p EXPERIYENT'L Dj. 'VELOPkjENT OF THE PRFDICTZFF. RETATIONS 1'OR T13E Fl)DY E1CH'NGF CO1'FFZCZENTS I'OR 3j...ONENTDF! 1'ND kicAT 13, Tl!E ATk!OSPkjERIC EcjUNDj!PY Ll TER A Thesi. s by PAUL ALFRED JENSEN APProved as to sty]e encl content by; (Cbairman of Cocami tree. ) ll!ead o= Departs nnl. , 'I' (t; /jc jJ. '~' (Member) l'jec em. bor ID; p c& rra Ai...

  13. Dynamics and energetics of the cloudy boundary layer in simulations of off-ice flow in the marginal ice zone

    E-Print Network [OSTI]

    Harrington, Jerry Y.

    kinetic energy even in the present case where very strong surface heat fluxes occur. Ice-phase. Inclusion of the ice phase significantly affected the radiative budget as compared to purely liquid clouds, illustrating the importance of ice-phase­radiative couplings for accurate simulations of arctic clouds

  14. DOI 10.1007/s10546-006-9050-z Boundary-Layer Meteorology (2006) 120: 315351 Springer 2006

    E-Print Network [OSTI]

    Ribes, Aurélien

    2006-01-01T23:59:59.000Z

    parametrization for the urban surface energy balance. A three-day period was modelled and evaluated against data THERMODYNAMIC ISLAND IN A COASTAL CITY ANALYSED FROM AN OPTIMIZED SURFACE NETWORK GR ´EGOIRE PIGEON,1, AUDE on the study of the urban atmosphere over the coastal city of Marseille. A methodology developed to optimize

  15. THE URBAN BOUNDARY-LAYER FIELD CAMPAIGN IN MARSEILLE (UBL/CLU-ESCOMPTE): SET-UP AND FIRST RESULTS

    E-Print Network [OSTI]

    Ribes, Aurélien

    was installed as part of UBL/CLU. Analysis objectives focus on (i) validation of several energy balance: Energy balance, Mapping land cover, Radiative fluxes, Thermal remote sensing, Turbulent fluxes, Urban breezes, and the related transport and diffusion of pollutants over different districts of the city

  16. A Large-Eddy Simulation Study of the Influence of Subsidence on the Stably Stratified Atmospheric Boundary Layer

    E-Print Network [OSTI]

    Mirocha, Jeffrey D.; Kosovi?, Branko

    2010-01-01T23:59:59.000Z

    to the surface of the snow/ice pack is often prevented byheat ?ux from the snow/ice pack interior, which constrainsover the Arctic Ocean snow/ice pack during clear-sky, winter

  17. The chemistry of OH and HO2 radicals in the boundary layer over the tropical Atlantic Ocean

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    B. , Hebestreit, K. , and Platt, U. : Short-lived alkylR. , Lawrence, M. G. , Platt, U. , and Crutzen, P. J. :Hebestreit, K. , Stutz, J. , and Platt, U. : Iodine oxide in

  18. The chemistry of OH and HO2 radicals in the boundary layer over the tropical Atlantic Ocean

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    CO and NO), respectively. Pwr is the laser power enterings). Using the above values and Pwr = 9 mW, LODs of 1.1×10 6

  19. Impact of the boundary layer on pointing and tracking in airborne free-space laser communication links

    E-Print Network [OSTI]

    Conrad, Ross Aaron

    2008-01-01T23:59:59.000Z

    Free-space laser communication is a developing technology with enormous potential to revolutionize the way people communicate across the globe. Of specific interest are air-to-space lasercom links. Such a link experiences ...

  20. The application of boundary layer removal to a 90 degree bend used as a flow turing device

    E-Print Network [OSTI]

    Smith, Edward Harrison

    1959-01-01T23:59:59.000Z

    Attached to Nozzle; High Velocity 30 Efficiency vs Percent Flow Removed; Bend. Attached to Nozzle; Low Velocity 31 Efficiency vs Percent Flow Removed; Bend Attached to 1. 5 Foot Duct; High Velocity 32 Efficiency vs Percent Flow Removed; Bend Attached... to 1. 5 Foot Duct; Low Velocity 33 Static Pressure vs Angle of Bend 37 38 40 41 A C K N 0 W L E D G E M E N T S The author wishes to express his appreciation to Profes- sor Alfred E. Cronk for his advice and patience; and to his wife, Annabelle...