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Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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1

Mesoscale convective complex vs. non-mesoscale convective complex thunderstorms: a comparison of selected meteorological variables  

E-Print Network [OSTI]

MESOSCALE CONVECTIVE CCMPLLX VS. NON-MESOSCALE CONVECTIVE COMPLEX THUNDERSTORMS: A COMPARISON OF SELECTED METEOROLOGICAL VARIABLES A Thesis MICHAkL EUGENE JJOOFARD Submitted to the Graduate College of Texas AJkM University in partial... by MICHAEL EUGENE HOOFARD Approved as to style and content by: a ter . enry (Chairman of Committee) %~5 44 c5 c usan gur c (Member) ona . oc ing (Member) ames . cogg (Head of Department) August 1986 ABSTRACT Nesoscale Convective Complex vs. Non...

Hoofard, Michael Eugene

1986-01-01T23:59:59.000Z

2

Natural convection airflow measurement and theory  

SciTech Connect (OSTI)

Natural convection is a major mechanism for heat distribution in many passive solar buildings, especially those with sunspaces. To better understand this mechanism, observations of air velocities and temperatures have been made in 13 different houses that encompass a wide variety of one- and two-story geometries. This paper extends previous reports. Results from one house are described in detail, and some generalizations are drawn from the large additional mass of data taken. A simple mathematical model is presented that describes the general nature of airflow and energy flow through an aperture.

Balcomb, J.D.; Jones, G.F.; Yamaguchi, Kenjiro

1984-01-01T23:59:59.000Z

3

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationCleanCommunity2Workshops01ControllingControls on SolubleConvection in

4

Heat transport measurements in turbulent rotating Rayleigh-Benard convection  

SciTech Connect (OSTI)

We present experimental heat transport measurements of turbulent Rayleigh-Benard convection with rotation about a vertical axis. The fluid, water with Prandtl number ({sigma}) about 6, was confined in a cell which had a square cross section of 7.3 cm x 7.3 cm and a height of 9.4 cm. Heat transport was measured for Rayleigh numbers 2 x 10{sup 5} < Ra < 5 x 10{sup 8} and Taylor numbers 0 < Ta < 5 x 10{sup 9}. We show the variation of normalized heat transport, the Nusselt number, at fixed dimensional rotation rate {Omega}{sub D}, at fixed Ra varying Ta, at fixed Ta varying Ra, and at fixed Rossby number Ro. The scaling of heat transport in the range 10{sup 7} to about 10{sup 9} is roughly 0.29 with a Ro dependent coefficient or equivalently is also well fit by a combination of power laws of the form a Ra{sup 1/5} + b Ra{sup 1/3} . The range of Ra is not sufficient to differentiate single power law or combined power law scaling. The overall impact of rotation on heat transport in turbulent convection is assessed.

Ecke, Robert E [Los Alamos National Laboratory; Liu, Yuanming [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

5

AERIAL MEASUREMENTS OF CONVECTION CELL ELEMENTS IN HEATED LAKES  

SciTech Connect (OSTI)

Power plant-heated lakes are characterized by a temperature gradient in the thermal plume originating at the discharge of the power plant and terminating at the water intake. The maximum water temperature discharged by the power plant into the lake depends on the power generated at the facility and environmental regulations on the temperature of the lake. Besides the observed thermal plume, cloud-like thermal cells (convection cell elements) are also observed on the water surface. The size, shape and temperature of the convection cell elements depends on several parameters such as the lake water temperature, wind speed, surfactants and the depth of the thermocline. The Savannah River National Laboratory (SRNL) and Clemson University are collaborating to determine the applicability of laboratory empirical correlations between surface heat flux and thermal convection intensity. Laboratory experiments at Clemson University have demonstrated a simple relationship between the surface heat flux and the standard deviation of temperature fluctuations. Similar results were observed in the aerial thermal imagery SRNL collected at different locations along the thermal plume and at different elevations. SRNL will present evidence that the results at Clemson University are applicable to cooling lakes.

Villa-Aleman, E; Saleem Salaymeh, S; Timothy Brown, T; Alfred Garrett, A; Malcolm Pendergast, M; Linda Nichols, L

2007-12-19T23:59:59.000Z

6

Measuring spatial variability in soil characteristics  

DOE Patents [OSTI]

The present invention provides systems and methods for measuring a load force associated with pulling a farm implement through soil that is used to generate a spatially variable map that represents the spatial variability of the physical characteristics of the soil. An instrumented hitch pin configured to measure a load force is provided that measures the load force generated by a farm implement when the farm implement is connected with a tractor and pulled through or across soil. Each time a load force is measured, a global positioning system identifies the location of the measurement. This data is stored and analyzed to generate a spatially variable map of the soil. This map is representative of the physical characteristics of the soil, which are inferred from the magnitude of the load force.

Hoskinson, Reed L. (Rigby, ID); Svoboda, John M. (Idaho Falls, ID); Sawyer, J. Wayne (Hampton, VA); Hess, John R. (Ashton, ID); Hess, J. Richard (Idaho Falls, ID)

2002-01-01T23:59:59.000Z

7

Atmospheric structure and variability in areas of convective storms determined from 3-h rawinsonde data  

E-Print Network [OSTI]

changes in TTI determined from charts in Fig. 58. . 101 60 61 62 Cumulative frequency distributions of changes in TTI in AVE II . . ~ . . . . . ~ Surface analysis at 2100 GMT, 11 May 1974 Satellite and radar composite at 2200 GMT, 11 May 1974 102... change in the probability of convective activity by a factor of 8 or more in 3 h. Between 30% and 60% of the total changes in parameters associated with convective activity over a 12-h period is shown to take place during a 3-h period. These large...

Wilson, Gregory Sims

2012-06-07T23:59:59.000Z

8

Application of a ratiometric laser induced fluorescence (LIF) thermometry for micro-scale temperature measurement for natural convection flows  

E-Print Network [OSTI]

A ratiometric laser induced fluorescence (LIF) thermometry applied to micro-scale temperature measurement for natural convection flows. To eliminate incident light non-uniformity and imperfection of recording device, two fluorescence dyes are used...

Lee, Heon Ju

2004-11-15T23:59:59.000Z

9

Ten Years of Measurements of Tropical Upper-Tropospheric Water Vapor by MOZAIC. Part I: Climatology, Variability, Transport, and Relation to  

E-Print Network [OSTI]

the International Satellite Cloud Climatology Project (ISCCP). 1. Introduction Water vapor is the key atmosphericTen Years of Measurements of Tropical Upper-Tropospheric Water Vapor by MOZAIC. Part I: Climatology, Variability, Transport, and Relation to Deep Convection ZHENGZHAO LUO, DIETER KLEY,* AND RICHARD H. JOHNSON

Lombardi, John R.

10

A Satellite Study of Tropical Moist Convection and Environmental Variability: A Moisture and Thermal Budget Analysis  

E-Print Network [OSTI]

radiometer and scatterometer aboard different platforms. Satellite measurements of atmospheric parameters of moisture and dry static energy and their vertical flux at cloud base from satellite observations alone convergence for highly organized systems; 2) FT diabatic heating is largely offset on an instantaneous basis

Masunaga, Hirohiko

11

Numerical investigation of CO{sub 2} emission and thermal stability of a convective and radiative stockpile of reactive material in a cylindrical pipe of variable thermal conductivity  

SciTech Connect (OSTI)

In this paper the CO{sub 2} emission and thermal stability in a long cylindrical pipe of combustible reactive material with variable thermal conductivity are investigated. It is assumed that the cylindrical pipe loses heat by both convection and radiation at the surface. The nonlinear differential equations governing the problem are tackled numerically using Runge-Kutta-Fehlberg method coupled with shooting technique method. The effects of various thermophysical parameters on the temperature and carbon dioxide fields, together with critical conditions for thermal ignition are illustrated and discussed quantitatively.

Lebelo, Ramoshweu Solomon, E-mail: sollyl@vut.ac.za [Department of Mathematics, Vaal University of Technology, Private Bag X021, Vanderbijlpark, 1911 (South Africa)

2014-10-24T23:59:59.000Z

12

Variable energy positron measurements at nitrogen ion bombarded steel surfaces  

SciTech Connect (OSTI)

Nitrogen ion bombardment of steel samples has been studied by utilizing the Delft variable energy positron beam facility. The energy of the beam was varied between 250 eV and 25 keV and a line-shape parameter S describing the annihilation radiation has been measured. By use of the VEPFIT fitting program, up to five different layers, each having different densities, could be identified and characterized. The results show that carbon layers deposited during nitrogen implantation can be observed. A relation between the measured depth profiles of nitrogen, carbon and oxygen by Elastic Recoil Detection Analysis (ERDA) and the results of positron annihilation is given and discussed. The wear and friction properties of the steel surfaces before and after nitrogen implantation are presented.

Brauer, G.; Kolitsch, A. [Research Centre Rossendorf, Inc., Dresden (Germany); Schut, H.; Veen, A. van [TU Delft (Netherlands). Interfaculty Reactor Inst.

1996-12-31T23:59:59.000Z

13

Comparison of atmospheric hydrology over convective continental regions using water vapor isotope measurements from space  

E-Print Network [OSTI]

. Correlation analysis shows that mixing with boundary layer air, enhanced isotopic fractionation during precipitation, and subsiding air parcels contribute to intraseasonal isotopic variability. These local controls distillation in a Lagrangrian framework underestimates the observed isotopic depletion during the monsoons

14

Reactor Engineering: Experimental Investigation of Alpha Convection  

SciTech Connect (OSTI)

Natural convection, Rayleigh-Bernard convection, Transient convection and Conduction convection transition.

Usman, Shoaib

2012-10-12T23:59:59.000Z

15

What measures climate? A variety of variables including their variability and extreme values determine climate for  

E-Print Network [OSTI]

climate zones? The sun is the ultimate power source for the climate "machine". The uneven distribution conditions. Typical variables to consider are temperature (maximum, miniumum), precipitation (includes rain, sleet, snow, hail, etc), sunlight/cloudiness, wind, humidity, ice cover, sea temperature, etc... Many

Allan, Richard P.

16

Variability in Measured Space Temperatures in 60 Homes  

SciTech Connect (OSTI)

This report discusses the observed variability in indoor space temperature in a set of 60 homes located in Florida, New York, Oregon, and Washington. Temperature data were collected at 15-minute intervals for an entire year, including living room, master bedroom, and outdoor air temperature (Arena, et. al). The data were examined to establish the average living room temperature for the set of homes for the heating and cooling seasons, the variability of living room temperature depending on climate, and the variability of indoor space temperature within the homes. The accuracy of software-based energy analysis depends on the accuracy of input values. Thermostat set point is one of the most influential inputs for building energy simulation. Several industry standards exist that recommend differing default thermostat settings for heating and cooling seasons. These standards were compared to the values calculated for this analysis. The data examined for this report show that there is a definite difference between the climates and that the data do not agree well with any particular standard.

Roberts, D.; Lay, K.

2013-03-01T23:59:59.000Z

17

ARM - Measurement - 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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Related InformationAciddroplet size ARM

18

Convection towers  

DOE Patents [OSTI]

Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water. 6 figs.

Prueitt, M.L.

1996-01-16T23:59:59.000Z

19

Convection towers  

DOE Patents [OSTI]

Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode.

Prueitt, Melvin L. (Los Alamos, NM)

1994-01-01T23:59:59.000Z

20

Convection towers  

DOE Patents [OSTI]

Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

Prueitt, Melvin L. (Los Alamos, NM)

1996-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Convection towers  

DOE Patents [OSTI]

Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

Prueitt, Melvin L. (Los Alamos, NM)

1995-01-01T23:59:59.000Z

22

Convection towers  

DOE Patents [OSTI]

Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode. 5 figures.

Prueitt, M.L.

1994-02-08T23:59:59.000Z

23

EPR-Steering measure for two-mode continuous variable states  

E-Print Network [OSTI]

Steering is a manifestation of quantum correlations that embodies the Einstein-Podolsky-Rosen (EPR) paradox. While there have been recent attempts to quantify steering, continuous variable systems remained elusive. We introduce a steering measure for two-mode continuous variable systems that is valid for arbitrary states. The measure is based on the violation of an optimized variance test for the EPR paradox, and admits a computable and experimentally friendly lower bound only depending on the second moments of the state, which reduces to a recently proposed quantifier of steerability by Gaussian measurements. We further show that Gaussian states are extremal with respect to our measure, minimizing it among all continuous variable states with fixed second moments. As a byproduct of our analysis, we generalize and relate well-known EPR-steering criteria. Finally an operational interpretation is provided, as the proposed measure is shown to quantify the optimal guaranteed key rate in semi-device independent qua...

Kogias, Ioannis

2014-01-01T23:59:59.000Z

24

EPR-Steering measure for two-mode continuous variable states  

E-Print Network [OSTI]

Steering is a manifestation of quantum correlations that embodies the Einstein-Podolsky-Rosen (EPR) paradox. While there have been recent attempts to quantify steering, continuous variable systems remained elusive. We introduce a steering measure for two-mode continuous variable systems that is valid for arbitrary states. The measure is based on the violation of an optimized variance test for the EPR paradox, and admits a computable and experimentally friendly lower bound only depending on the second moments of the state, which reduces to a recently proposed quantifier of steerability by Gaussian measurements. We further show that Gaussian states are extremal with respect to our measure, minimizing it among all continuous variable states with fixed second moments. As a byproduct of our analysis, we generalize and relate well-known EPR-steering criteria. Finally an operational interpretation is provided, as the proposed measure is shown to quantify the optimal guaranteed key rate in semi-device independent quantum key distribution.

Ioannis Kogias; Gerardo Adesso

2014-11-03T23:59:59.000Z

25

Atmospheric Radiation Measurement (ARM) Data from Black Forest Germany for the Convective and Orographically Induced Precipitation Study (COPS)  

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

The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. ARM maintains four major, permanent sites for data collection and deploys the ARM Mobile Facility (AMF) to other sites as determined. In 2007 the AMF operated in the Black Forest region of Germany as part of the Convective and Orographically Induced Precipitation Study (COPS). Scientists studied rainfall resulting from atmospheric uplift (convection) in mountainous terrain, otherwise known as orographic precipitation. This was part of a six -year duration of the German Quantitative Precipitation Forecasting (QPF) Program. COPS was endorsed as a Research and Development Project by the World Weather Research Program. This program was established by the World Meteorological Organization to develop improved and cost-effective forecasting techniques, with an emphasis on high-impact weather. A large collection of data plots based on data streams from specific instruments used at Black Forest are available via a link from ARM's Black Forest site information page. Users will be requested to create a password, but the plots and the data files in the ARM Archive are free for viewing and downloading.

26

Correlation of seismotectonic variables and GPS strain measurements in western Turkey  

E-Print Network [OSTI]

Correlation of seismotectonic variables and GPS strain measurements in western Turkey Ali Osman O Mediterranean and western Turkey area. This analysis was conducted in three tectonic subdivisions corresponding measurements in western Turkey, J. Geophys. Res., 109, B11306, doi:10.1029/2004JB003101. 1. Introduction [2

Wilson, Thomas H.

27

Convective heater  

DOE Patents [OSTI]

A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

Thorogood, Robert M. (Macungie, PA)

1986-01-01T23:59:59.000Z

28

Convective heater  

DOE Patents [OSTI]

A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation. 14 figs.

Thorogood, R.M.

1983-12-27T23:59:59.000Z

29

Midlatitude Continental Convective Clouds Experiment (MC3E)  

SciTech Connect (OSTI)

Convective processes play a critical role in the Earth’s energy balance through the redistribution of heat and moisture in the atmosphere and subsequent impacts on the hydrologic cycle. Global observation and accurate representation of these processes in numerical models is vital to improving our current understanding and future simulations of Earth’s climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales that are associated with convective and stratiform precipitation processes; therefore, they must turn to parameterization schemes to represent these processes. In turn, the physical basis for these parameterization schemes needs to be evaluated for general application under a variety of atmospheric conditions. Analogously, space-based remote sensing algorithms designed to retrieve related cloud and precipitation information for use in hydrological, climate, and numerical weather prediction applications often rely on physical “parameterizations” that reliably translate indirectly related instrument measurements to the physical quantity of interest (e.g., precipitation rate). Importantly, both spaceborne retrieval algorithms and model convective parameterization schemes traditionally rely on field campaign data sets as a basis for evaluating and improving the physics of their respective approaches. The Midlatitude Continental Convective Clouds Experiment (MC3E) will take place in central Oklahoma during the April–May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and the National Aeronautics and Space Administration’s (NASA) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The field campaign leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that have never before been available. Several different components of convective cloud and precipitation processes tangible to both the convective parameterization and precipitation retrieval algorithm problem are targeted, such as preconvective environment and convective initiation, updraft/downdraft dynamics, condensate transport and detrainment, precipitation and cloud microphysics, spatial and temporal variability of precipitation, influence on the environment and radiation, and a detailed description of the large-scale forcing.

Jensen, MP; Petersen, WA; Del Genio, AD; Giangrande, SE; Heymsfield, A; Heymsfield, G; Hou, AY; Kollias, P; Orr, B; Rutledge, SA; Schwaller, MR; Zipser, E

2010-04-01T23:59:59.000Z

30

ECG-Derived Respiration: Comparison and New Measures for Respiratory Variability  

E-Print Network [OSTI]

ECG-Derived Respiration: Comparison and New Measures for Respiratory Variability Devy Widjaja1 During ECG recording, several methods can be applied to derive a respiratory signal from the ECG (EDR signal). In this paper 4 EDR methods, including ECG filtering, R and RS amplitude based techniques

31

A Climatological measurement methods This appendix describes the methods of climatological variable measurement at the  

E-Print Network [OSTI]

and a comparison of sensors employed. The measurement methods section describes the sensors used-wave A sensor used to measure the energy flux density of short-wave radiation is referred to as a pyranometer can be ±3 to 5% because of the relatively constant proportions of solar radiation at different

32

SURFACE TENSION DRIVEN CONVECTION  

E-Print Network [OSTI]

SURFACE TENSION DRIVEN CONVECTION DIJKSTRA, SENGUL, WANG INTRODUCTION LINEAR THEORY MAIN THEOREMS CONCLUDING REMARKS DYNAMIC TRANSITIONS OF SURFACE TENSION DRIVEN CONVECTION H.Dijkstra T. Sengul S. Wang #12;SURFACE TENSION DRIVEN CONVECTION DIJKSTRA, SENGUL, WANG INTRODUCTION LINEAR THEORY MAIN THEOREMS

Wang, Shouhong

33

Measurement of normal thrust and evaluation of upper-convected Maxwell models for molten plastics in large amplitude oscillatory shear  

E-Print Network [OSTI]

with Relaxation Spectrum Re- ported by Khan and Larson (1987) . IV. 5 Normal Thrust Measurements IV. 6 Mewts-Denn Model Compared With Normal Thrust Measure- ments 37 42 44 46 49 V CONCLUSION REFERENCES APPENDIX FIGURES . . APPENDIX Pa, ge B FIRST... tensor, this is also referred to as the Maxwell model. I. 5 1 Maxwell Model Dealy and Wissbrun (1990) give the Boltzmann superposition principle in the material objective (ie. frame indifferent) integral form in terms of a memory function...

Oakley, Jason Glen

1992-01-01T23:59:59.000Z

34

Differences between measured and linearly interpolated synoptic variables over a 12-h period during AVE IV  

E-Print Network [OSTI]

, Z4 April 1975. (after Fucik and Turner, 1975). 590 440 1D 1Dy ~ m 9 soo 530 560 18~ 530 I 22 ? g --' I / '3 22 0 590 20 338 530 16 850 mb 4 4 090 8 m 2D ? ? ? 6 ( ', -k 5 150 8 I '30 ~ 8O '4 210 210 700 BIb Fig. 6. (Cont3nued...DIFFERENCES BETWEEN MEASURED AND LINEARLY INTERPOLATED SYNOPTIC VARIABLES OVER A 12-h PERIOD DURING AVE IV A Thesis by LEONARD RAYMOND DUPUIS Submitted to the Graduate College of Texas A&M University in partial ful. fillment...

Dupuis, Leonard Raymond

1979-01-01T23:59:59.000Z

35

Abstract--Heart rate variability (HRV) is frequently used to measure autonomic nervous system (ANS) activity. However,  

E-Print Network [OSTI]

1 of 4 Abstract--Heart rate variability (HRV) is frequently used to measure autonomic nervous frequency (HF) ratio with little change in mean heart rate. Results suggest that nicotine affects both components may yield erroneous results. Keywords--Autonomic regulation, heart rate variability, Lomb

36

Convective heat flow probe  

DOE Patents [OSTI]

A convective heat flow probe device is provided which measures heat flow and fluid flow magnitude in the formation surrounding a borehole. The probe comprises an elongate housing adapted to be lowered down into the borehole; a plurality of heaters extending along the probe for heating the formation surrounding the borehole; a plurality of temperature sensors arranged around the periphery of the probe for measuring the temperature of the surrounding formation after heating thereof by the heater elements. The temperature sensors and heater elements are mounted in a plurality of separate heater pads which are supported by the housing and which are adapted to be radially expanded into firm engagement with the walls of the borehole. The heat supplied by the heater elements and the temperatures measured by the temperature sensors are monitored and used in providing the desired measurements. The outer peripheral surfaces of the heater pads are configured as segments of a cylinder and form a full cylinder when taken together. A plurality of temperature sensors are located on each pad so as to extend along the length and across the width thereof, with a heating element being located in each pad beneath the temperature sensors. An expansion mechanism driven by a clamping motor provides expansion and retraction of the heater pads and expandable packet-type seals are provided along the probe above and below the heater pads.

Dunn, J.C.; Hardee, H.C.; Striker, R.P.

1984-01-09T23:59:59.000Z

37

ARM Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product  

SciTech Connect (OSTI)

ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties, using the following relationships;

Jensen, Michael

2014-04-10T23:59:59.000Z

38

ARM Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product  

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

ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties, using the following relationships;

Jensen, Michael

39

MEASURING X-RAY VARIABILITY IN FAINT/SPARSELY SAMPLED ACTIVE GALACTIC NUCLEI  

SciTech Connect (OSTI)

We study the statistical properties of the normalized excess variance of variability process characterized by a ''red-noise'' power spectral density (PSD), as in the case of active galactic nuclei (AGNs). We perform Monte Carlo simulations of light curves, assuming both a continuous and a sparse sampling pattern and various signal-to-noise ratios (S/Ns). We show that the normalized excess variance is a biased estimate of the variance even in the case of continuously sampled light curves. The bias depends on the PSD slope and on the sampling pattern, but not on the S/N. We provide a simple formula to account for the bias, which yields unbiased estimates with an accuracy better than 15%. We show that the normalized excess variance estimates based on single light curves (especially for sparse sampling and S/N < 3) are highly uncertain (even if corrected for bias) and we propose instead the use of an ''ensemble estimate'', based on multiple light curves of the same object, or on the use of light curves of many objects. These estimates have symmetric distributions, known errors, and can also be corrected for biases. We use our results to estimate the ability to measure the intrinsic source variability in current data, and show that they could also be useful in the planning of the observing strategy of future surveys such as those provided by X-ray missions studying distant and/or faint AGN populations and, more in general, in the estimation of the variability amplitude of sources that will result from future surveys such as Pan-STARRS and LSST.

Allevato, V. [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, FI-00014 Helsinki (Finland); Paolillo, M. [Department of Physical Sciences, University Federico II, via Cinthia 6, I-80126 Naples (Italy); Papadakis, I. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, 71003 Heraklion (Greece); Pinto, C. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584-CA Utrecht (Netherlands)

2013-07-01T23:59:59.000Z

40

Origins of convective activity over Panama  

E-Print Network [OSTI]

Satellite-derived outgoing longwave radiation (OLR) data. were used to examine convective variability over the Panama region. Time series analysis of the area- averaged daily OLR data, for 1984 and 1985 revealed a, persistent 12-d oscillation... in convective activity during each season. Composite analyses of OLR data, for the area 120'W-40'W and 35'S-35'N for the 1984 dry (1 January ? 9 May) and wet (10 Msy? 4 December) seasons showed this oscillation extends beyond Panama and the Central America...

Strager, Christopher Stephen

1989-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

A new measure of acceleration of heart rate: dependence on age and comparison with time domain conventional heart rate variability measures  

E-Print Network [OSTI]

A new measure of acceleration of heart rate: dependence on age and comparison with time domain conventional heart rate variability measures Giuseppe Germanò, M.D., Gianfranco Piccirillo, M.D., *Camillo We introduce a new index, Acceleration Ratio (AR), in order to investigate the dependence of Heart

Cammarota, Camillo

42

5, 1102911054, 2005 Convective gravity  

E-Print Network [OSTI]

ACPD 5, 11029­11054, 2005 Convective gravity waves at mid-latitudes Y. G. Choi et al. Title Page Discussions Wind-profiler observations of gravity waves produced by convection at mid-latitudes Y. G. Choi1­11054, 2005 Convective gravity waves at mid-latitudes Y. G. Choi et al. Title Page Abstract Introduction

Paris-Sud XI, Université de

43

Convective Cloud Lifecycles Lunchtime seminar  

E-Print Network [OSTI]

Convective Cloud Lifecycles Lunchtime seminar 19th May 2009 Bob Plant Department of Meteorology, University of Reading, UK #12;Introduction Obtain life cycle statistics for clouds in CRM simulations Why Conclusions Convective Cloud Lifecycles ­ p.1/3 #12;Why bother? Convective Cloud Lifecycles ­ p.2/3 #12;Some

Plant, Robert

44

Measure Guideline: Replacing Single-Speed Pool Pumps with Variable Speed Pumps for Energy Savings  

SciTech Connect (OSTI)

The report evaluates potential energy savings by replacing traditional single-speed pool pumps with variable speed pool pumps, and provide a basic cost comparison between continued uses of traditional pumps verses new pumps. A simple step-by-step process for inspecting the pool area and installing a new pool pump follows.

Hunt, A.; Easley, S.

2012-05-01T23:59:59.000Z

45

On-shell constrained $M_2$ variables with applications to mass measurements and topology disambiguation  

E-Print Network [OSTI]

We consider a class of on-shell constrained mass variables that are 3+1 dimensional generalizations of the Cambridge $M_{T2}$ variable and that automatically incorporate various assumptions about the underlying event topology. The presence of additional on-shell constraints causes their kinematic distributions to exhibit sharper endpoints than the usual $M_{T2}$ distribution. We study the mathematical properties of these new variables, e.g., the uniqueness of the solution selected by the minimization over the invisible particle 4-momenta. We then use this solution to reconstruct the masses of various particles along the decay chain. We propose several tests for validating the assumed event topology in missing energy events from new physics. The tests are able to determine: 1) whether the decays in the event are two-body or three-body, 2) if the decay is two-body, whether the intermediate resonances in the two decay chains are the same, and 3) the exact sequence in which the visible particles are emitted from each decay chain.

Won Sang Cho; James S. Gainer; Doojin Kim; Konstantin T. Matchev; Filip Moortgat; Luc Pape; Myeonghun Park

2015-03-25T23:59:59.000Z

46

Temporal variability of the trade wind inversion: Measured with a boundary layer vertical profiler. Master's thesis  

SciTech Connect (OSTI)

This study uses Hawaiian Rainband Project (HaRP) data, from the summer of 1991, to show a boundary layer wind profiler can be used to measure the trade wind inversion. An algorithm has been developed for the profiler that objectively measures the depth of the moist oceanic boundary layer. The Hilo inversion, measured by radiosonde, is highly correlated with the moist oceanic boundary layer measured by the profiler at Paradise Park. The inversion height on windward Hawaii is typically 2253 + or - 514 m. The inversion height varies not only on a daily basis, but on less than an hourly basis. It has a diurnal, as well as a three to four day cycle. There appears to be no consistent relationship between inversion height and precipitation. Currently, this profiler is capable of making high frequency (12 minute) measurements of the inversion base variation, as well as other features.

Grindinger, C.M.

1992-05-01T23:59:59.000Z

47

Dimension Reduction with Gene Expression Data Using Targeted Variable Importance Measurement  

E-Print Network [OSTI]

and we refer to it as the TMLE-VIM procedure. 1. Obtain theResults: We propose a TMLE-VIM dimension reduction procedureimportance measurement (VIM) in the frame work of targeted

Wang, Hui; van der Laan, Mark J

2011-01-01T23:59:59.000Z

48

Measuring Spatial Variability of Vapor Flux to Characterize Vadose-zone VOC Sources: Flow-cell Experiments  

SciTech Connect (OSTI)

A method termed vapor-phase tomography has recently been proposed to characterize the distribution of volatile organic contaminant mass in vadose-zone source areas, and to measure associated three-dimensional distributions of local contaminant mass discharge. The method is based on measuring the spatial variability of vapor flux, and thus inherent to its effectiveness is the premise that the magnitudes and temporal variability of vapor concentrations measured at different monitoring points within the interrogated area will be a function of the geospatial positions of the points relative to the source location. A series of flow-cell experiments was conducted to evaluate this premise. A well-defined source zone was created by injection and extraction of a non-reactive gas (SF6). Spatial and temporal concentration distributions obtained from the tests were compared to simulations produced with a mathematical model describing advective and diffusive transport. Tests were conducted to characterize both areal and vertical components of the application. Decreases in concentration over time were observed for monitoring points located on the opposite side of the source zone from the local–extraction point, whereas increases were observed for monitoring points located between the local–extraction point and the source zone. The results illustrate that comparison of temporal concentration profiles obtained at various monitoring points gives a general indication of the source location with respect to the extraction and monitoring points.

Mainhagu, Jon; Morrison, C.; Truex, Michael J.; Oostrom, Martinus; Brusseau, Mark

2014-10-20T23:59:59.000Z

49

Synergistic Effect of coal blends on thermoplasticity evaluated using a temperature-variable dynamic viscoelastic measurement  

SciTech Connect (OSTI)

To maximize the conversion of low-quality coal into good coke, we investigated the thermoplasticity of various binary blends of caking coals with slightly or noncaking coals using a dynamic viscoelastic technique with a temperature-variable rheometer. Coal blend samples were prepared by mixing two coals (1:1 by weight), which were heated from room temperature to 600 C at a rate of 3-80{sup o}C/min. At the slow rate of 3{sup o}C/min, the blends had a tan {delta} that was generally lower than the calculated value, showing that a negative interaction caused a loss of thermoplasticity. In contrast, at the rapid heating rate of 80{sup o}C/min, the tan {delta} of some blends was higher than the calculated value, indicating a positive interaction that enhanced the thermoplasticity. With rapid heating, the thermoplasticity of each coal itself increased, and their thermoplastic temperature ranges widened with rapid heating. Therefore, rapid heating was effective at converting these coal blends into good cokes. Moreover, even with slow heating, when a combination of coals (Gregory:Enshu, 1:1) showing some thermoplasticity in nearly the same temperature range was blended, a desirable synergistic effect of the blend was obtained. This suggests that blending coal with an overlapping thermoplastic temperature range is important for the synergistic effect, regardless of the heating rate. 15 refs., 9 figs., 2 tabs.

Toshimasa Takanohashi; Takahiro Shishido; Ikuo Saito; Kensuke Masaki; Atsushi Dobashi; Kiyoshi Fukada [National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan)

2006-12-15T23:59:59.000Z

50

Kinematic measures and stroke rate variability in elite female 200-m swimmers in the four swimming techniques: Athens 2004 Olympic semi-finalists and French National  

E-Print Network [OSTI]

1 Kinematic measures and stroke rate variability in elite female 200-m swimmers in the four of this work was to study stroke rate variability in elite female swimmers (200-m events, all four techniques semi-finalists (group N, n=64). Since swimming speed (V) is the product of stroke rate (SR) and stroke

Paris-Sud XI, Université de

51

Dose measurements behind reduced shielding at the Texas A&M University variable energy cyclotron  

E-Print Network [OSTI]

the reduced shielding by measuring neutron and gamma ray dose rates. A listing of currently available beams that are included in the study is given in Table 1. The purpose of this study is to provide information that can be used to limit radiation... conducted into accelerator shielding. It is known that a shield which is adequate to attenuate the high energy neutron component of the incident radiation will be more than enough to contain the charged particle and gamma ray com- ponents (NCRP77...

Kay, Douglas Carey

1982-01-01T23:59:59.000Z

52

Measuring Spatial Variability of Vapor Flux to Characterize Vadose-zone VOC  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces andMapping the Nanoscale LandscapeImportsBG4,Measurements

53

Simultaneous measurements of several state variables in shocked carbon by imaging x-ray scattering  

SciTech Connect (OSTI)

We apply the novel experimental technique of imaging x-ray Thomson scattering to measure the spatial profiles of the temperature, ionization state, relative material density, and the shock speed in a high-energy density system. A blast wave driven in a low-density foam is probed with 90? scattering of 7.8?keV helium-like nickel x-rays, which are spectrally dispersed and resolved in one spatial dimension by a doubly curved crystal. The inferred properties of the shock are shown to be self-consistent with 1D analytical estimates. These high-resolution measurements enable a direct comparison of the observed temperature with the results from hydrodynamic simulations. We find good agreement with the simulations for the temperature at the shock front but discrepancies in the modeling of the spatial temperature profile and shock speed. These results indicate the challenges in modeling the shock dynamics of structured materials like foams, commonly used in many high-energy density and laboratory astrophysics experiments.

Gamboa, E. J., E-mail: eliseo@umich.edu; Drake, R. P.; Keiter, P. A.; Trantham, M. R. [University of Michigan, Ann Arbor, Michigan 48109 (United States)] [University of Michigan, Ann Arbor, Michigan 48109 (United States); Falk, K.; Montgomery, D. S.; Benage, J. F. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2014-04-15T23:59:59.000Z

54

Different convection models in ATLAS  

E-Print Network [OSTI]

Convection is an important phenomenon in the atmospheres of A-type and cooler stars. A description of convection in ATLAS models is presented, together with details of how it is specified in model calculations. The effects of changing the treatment of convection on model structures and how this affects observable quantities are discussed. The role of microturbulence is examined, and its link to velocity fields within the atmosphere. Far from being free parameters, mixing-length and microturbulence should be constrained in model calculations.

Barry Smalley

2005-09-19T23:59:59.000Z

55

Heat distribution by natural convection  

SciTech Connect (OSTI)

Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

Balcomb, J.D.; Yamaguchi, K.

1983-01-01T23:59:59.000Z

56

Heat distribution by natural convection  

SciTech Connect (OSTI)

Natural convection can provide adequate heat distribution in many situtations that arise in buildings. This is appropriate, for example, in passive solar buildings where some rooms tend to be more strongly solar heated than others or to reduce the number of heating units required in a building. Natural airflow and heat transport through doorways and other internal building apertures is predictable and can be accounted for in the design. The nature of natural convection is described, and a design chart is presented appropriate to a simple, single-doorway situation. Natural convective loops that can occur in buildings are described and a few design guidelines are presented.

Balcomb, J.D.

1985-01-01T23:59:59.000Z

57

Natural convection heat transfer within horizontal spent nuclear fuel assemblies  

SciTech Connect (OSTI)

Natural convection heat transfer is experimentally investigated in an enclosed horizontal rod bundle, which characterizes a spent nuclear fuel assembly during dry storage and/or transport conditions. The basic test section consists of a square array of sixty-four stainless steel tubular heaters enclosed within a water-cooled rectangular copper heat exchanger. The heaters are supplied with a uniform power generation per unit length while the surrounding enclosure is maintained at a uniform temperature. The test section resides within a vacuum/pressure chamber in order to subject the assembly to a range of pressure statepoints and various backfill gases. The objective of this experimental study is to obtain convection correlations which can be used in order to easily incorporate convective effects into analytical models of horizontal spent fuel systems, and also to investigate the physical nature of natural convection in enclosed horizontal rod bundles in general. The resulting data consist of: (1) measured temperatures within the assembly as a function of power, pressure, and backfill gas; (2) the relative radiative contribution for the range of observed temperatures; (3) correlations of convective Nusselt number and Rayleigh number for the rod bundle as a whole; and (4) correlations of convective Nusselt number as a function of Rayleigh number for individual rods within the array.

Canaan, R.E.

1995-12-01T23:59:59.000Z

58

Seasonal and ENSO variability in global ocean phytoplankton chlorophyll derived from 4 years of SeaWiFS measurements  

E-Print Network [OSTI]

of a possible 184 modes, which explain 67% of the total temporal variability associated with the global meanSeasonal and ENSO variability in global ocean phytoplankton chlorophyll derived from 4 years of Sea and other sources of phytoplankton variability on global scales, which is an important component

Yoder, James S.

59

Heat distribution by natural convection  

SciTech Connect (OSTI)

Natural convection can provide adequate heat distribution in many situations that arise in buildings. This is appropriate, for example, in passive solar buildings where some rooms tend to be more strongly solar heated than others. Natural convection can also be used to reduce the number of auxiliary heating units required in a building. Natural airflow and heat transport through doorways and other internal building apertures are predictable and can be accounted for in the design. The nature of natural convection is described, and a design chart is presented appropriate to a simple, single-doorway situation. Experimental results are summarized based on the monitoring of 15 passive solar buildings which employ a wide variety of geometrical configurations including natural convective loops.

Balcomb, J.D.

1985-01-01T23:59:59.000Z

60

Passive microwave observations of mesoscale convective systems over the tropical Pacific Ocean  

E-Print Network [OSTI]

This paper presents high resolution passive microwave measurements obtained in the western Pacific warm pool region. These measurements represent the first comprehensive observations of convection over the tropical oceans, and were obtained from...

McGaughey, Gary Rae

1994-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

A solution of the measurement problem in quantum mechanics by using a variable hidden in Newtonian mechanics  

E-Print Network [OSTI]

The problem of a correct description of the physical phenomena of the Heisenberg uncertainty relation is solved by using a variable hidden in Newtonian mehcanics.

Jae-Hyung Myung

2012-03-29T23:59:59.000Z

62

Atmospheric Radiation Measurement Convective and Orographically Induced  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAbout theOFFICEAmesApplication2ArgonneAssemblyDemandPlasma4

63

ARM - Midlatitude Continental Convective Clouds  

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

Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

Jensen, Mike; Bartholomew, Mary Jane; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

64

Data assimilation for stratified convection  

E-Print Network [OSTI]

We show how the 3DVAR data assimilation methodology can be used in the astrophysical context of a two-dimensional convection flow. We study the way this variational approach finds best estimates of the current state of the flow from a weighted average of model states and observations. We use numerical simulations to generate synthetic observations of a vertical two-dimensional slice of the outer part of the solar convection zone for varying noise levels and implement 3DVAR when the covariance matrices are scalar. Our simulation results demonstrate the capability of 3DVAR to produce error estimates of system states between up to tree orders of magnitude below the original noise level present in the observations. This work exemplifies the importance of applying data assimilation techniques in simulations of the stratified convection.

Svedin, Andreas; Brandenburg, Axel

2013-01-01T23:59:59.000Z

65

Measurement of charged-particle event shape variables in inclusive ?(s)=7??TeV proton-proton interactions with the ATLAS detector  

E-Print Network [OSTI]

The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse ...

Taylor, Frank E.

66

GAMS program used to estimate capacity with the hyperbolic graph efficiency measure, with variable returns to scale and undesirable outputs.  

E-Print Network [OSTI]

. "Estimating Capacity and Efficiency in Fisheries with Undesirable Outputs." VIMS Marine resource Report N(obs) weights gamma(obs,var) ; POSITIVE Variable weight, gamma; EQUATIONS CONSTR1(GOUTPUT, OBS) DEA constraint

67

variability temperature  

E-Print Network [OSTI]

balance benguela biases buoyancy cod comparisons convection cooling energy error estimation fluctuations related relative remote resolution results sampling ships studies validation weather world approach pacificocean phase plankton predictability present principal shelf shift simulated southwest statistics

68

NATURAL CONVECTION IN ROOM GEOMETRIES  

SciTech Connect (OSTI)

Computer programs have been developed to numerically simulate natural convection in room geometries in two and three dimensions. The programs have been validated using published data from the literature, results from a full-scale experiment performed at Massachusetts Institute of Technology, and results from a small-scale experiment reported here. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single thermal zone in a direct-gain passive solar building. The results indicate that the building heating loads calculated by standard building energy analysis methods may be in error by as much as 50% as a result of their use of common assumptions regarding the convection processes which occur in an enclosure. It is also found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface.

Gadgil, A.; Bauman, Fred; Kammerud, R.; Ruberg, K.

1980-06-01T23:59:59.000Z

69

A comparison of light and velocity variations in Semiregular variables  

E-Print Network [OSTI]

NIR velocity variations are compared with simultaneous visual light curves for a sample of late-type semiregular variables (SRV). Precise radial velocity measurements are also presented for the SRV V450 Aql. Our aim is to investigate the nature of the irregular light changes found in these variables. Light and velocity variations are correlated in all stars of our sample. Based on these results we discuss several possibilities to explain the observed behavior. We find that pulsation is responsible for large amplitude variations. In a recent paper Lebzelter (1999) invoked large convective cells to understand observed velocity variations. This possibility is discussed with respect to the observed correlation between light and velocity changes. In the light of these results we investigate the origin of the semiregular variations.

T. Lebzelter; L. L. Kiss; K. H. Hinkle

2000-09-21T23:59:59.000Z

70

Convective cell development and propagation in a mesoscale convective complex  

E-Print Network [OSTI]

~ , National Fisheries University of Pusan Chairman of Advisory Committee: Dr ~ Kennth CD Brundidge A case study was made of the mesoscale convective complex (MCC) which occurred over southern Oklahoma and northern Texas on 27 May 1981. This storm moved... in an east-southeasterly direction and during much of its lifetime was observable by radars at Oklahoma City, OK and Stephenville, TX. It was found that the direction of cell (VIP level 3 or more reflectivity) propagation was somewhat erratic...

Ahn, Yoo-Shin

2012-06-07T23:59:59.000Z

71

Advection, Moistening, and Shallow-to-deep Convection Transitions During the Initiation and Propagation of Madden-Julian Oscillation  

SciTech Connect (OSTI)

Using observations from the 2011 AMIE/DYNAMO field campaign over the Indian Ocean and a high-resolution regional model simulation, the processes that lead to the rapid shallow-to-deep convection transitions associated with the initiation and eastward propagation of the Madden-Julian Oscillation (MJO) are examined. By tracking the evolution of the depth of several thousand individual model simulated precipitation features, the role of and the processes that control the observed midtropospheric moisture buildup ahead of the detection of deep convection are quantified at large and convection scales. The frequency of shallow-to-deep convection transitions is found to be sensitive to this midlevel moisture and large-scale uplift. This uplift along with the decline of large-scale drying by equator-ward advection causes the moisture buildup leading to the initiation of the MJO. Convection scale moisture variability and uplift, and large-scale zonal advection play secondary roles.

Hagos, Samson M.; Feng, Zhe; Landu, Kiranmayi; Long, Charles N.

2014-09-11T23:59:59.000Z

72

Measurement of charged-particle event shape variables in inclusive ?(s)=7??TeV proton-proton interactions with the ATLAS detector  

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

The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor, and transverse sphericity, each defined using the final-state charged particles’ momentum components perpendicular to the beam direction. Events with at least six charged particles are selected by a minimum-bias trigger. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged-particle transverse momentum, charged-particle multiplicity, and summed transverse momentum is presented. Predictions from several Monte Carlo models show significant deviations from data.

Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdelalim, A. A.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Agustoni, M.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Allbrooke, B. M. M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amram, N.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Arfaoui, S.; Arguin, J-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Atkinson, M.; Aubert, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Avramidou, R.; Axen, D.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, V.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beale, S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, A. K.; Becker, S.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Begel, M.; Behar Harpaz, S.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertella, C.; Bertin, A.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bittner, B.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Booth, C. N.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borri, M.; Borroni, S.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Bremer, J.; Brendlinger, K.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Broggi, F.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Buat, Q.; Bucci, F.; Buchanan, J.; Buchholz, P.; Buckingham, R. M.

2013-08-01T23:59:59.000Z

73

Elastic Convection in Vibrated Viscoplastic Fluids  

E-Print Network [OSTI]

We observe a new type of behavior in a shear thinning yield stress fluid: freestanding convection rolls driven by vertical oscillation. The convection occurs without the constraint of container boundaries yet the diameter of the rolls is spontaneously selected for a wide range of parameters. The transition to the convecting state occurs without hysteresis when the amplitude of the plate acceleration exceeds a critical value. We find that a non-dimensional stress, the stress due to the inertia of the fluid normalized by the yield stress, governs the onset of the convective motion.

Hayato Shiba; Jori Ruppert-Felsot; Yoshiki Takahashi; Yoshihiro Murayama; Qi Ouyang; Masaki Sano

2006-08-07T23:59:59.000Z

74

Energy transport using natural convection boundary layers  

SciTech Connect (OSTI)

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.

Anderson, R.

1986-04-01T23:59:59.000Z

75

Slide 1Falk Herwig7 Aug 2006 Convective and non-convective mixing  

E-Print Network [OSTI]

Slide 1Falk Herwig7 Aug 2006 Convective and non-convective mixing in AGB stars Falk Herwig and Bernd Freytag Los Alamos National Laboratory Theoretical Astrophysics Group #12;Slide 2Falk Herwig7 Aug envelope models for sun-like stars #12;Slide 3Falk Herwig7 Aug 2006 3D hydro simulations of AGB convective

Herwig, Falk

76

Midlatitude Continental Convective Clouds Experiment (MC3E)  

SciTech Connect (OSTI)

The Midlatitude Continental Convective Clouds Experiment (MC3E) will take place in central Oklahoma during the April–May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and the National Aeronautics and Space Administration’s (NASA) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The field campaign leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that have never before been available.

Jensen, MP; Petersen, WA; Del Genio, AD; Giangrande, SE; Heymsfield, A; Heymsfield, G; Hou, AY; Kollias, P; Orr, B; Rutledge, SA; Schwaller, MR; Zipser, E

2010-04-10T23:59:59.000Z

77

The development and application of a questionnaire designed to measure pre-existing, process, and outcome variables in the productivity measurement and enhancement  

E-Print Network [OSTI]

measurement: 1. Takes guesswork out of observation about productivity 2. Assists in the efficient conduct of operations. 3. Facilitates communication between members of the organization. 4. Aids in evaluating progress toward improving productivity. 5...

Decuir, Arlette Desha

1997-01-01T23:59:59.000Z

78

Moving-Boundary Heat Exchanger Models with Variable Outlet Phase, ASME Journal of Dynamic Systems, Measurement, and Control  

E-Print Network [OSTI]

, MEASUREMENT, AND CON- ROL. Manuscript received June 8, 2006; final manuscript received May 22, 2008; ublished online September 24, 2008. Assoc. Editor: Huei Peng. ournal of Dynamic Systems, Measurement, and Control NOVEMBER 2008, Vol. 130 / 061003-1Brian D.... Eldredge University of Illinois at Urbana-Champaign, 158 MEB, MC-244, 1206 West Green Street, Urbana, IL 61801 e-mail: brian.eldredge@gmail.com Bryan P. Rasmussen Texas A&M University, 3123 TAMU, College Station, TX 77843-3123 e-mail: brasmussen...

Eldredge, B.D; Rasmussen, B.P.; Alleyne, A.

79

Realistic Solar Convection Simulations Robert F. Stein  

E-Print Network [OSTI]

Realistic Solar Convection Simulations Robert F. Stein Michigan State University, East Lansing, MIAFG, Juliane Maries Vej 30, Dk­2100 Copenhagen �, Denmark Abstract. We report on realistic simulations of solar and intensity spectra, the p­mode excitation rate, and the depth of the convection zone. We describe how solar

Stein, Robert

80

High Variability of the Metal Content of Tree Growth Rings as Measured by Synchrotron Micro X-ray Fluorescence Spectrometry  

SciTech Connect (OSTI)

Synchrotron radiation analysis was used to investigate the metal content of tree rings collected from paper birch, Betula papyrifera Marsh, on transects downwind from two metal smelters (nickel and copper). Individual trees reflected changes in ring metal content with time, which may be presumed to represent changes in local metal bioavailability. However, between-tree variations were large and no statistically significant differences in metal content as a function of time were found within or between sites. Although concentrations of both total and exchangeable copper and nickel in the soil increased with proximity to the respective smelter, this pattern was reflected only in the nickel content of rings near the nickel smelter; copper content did not vary with distance from either smelter. The sites did differ with respect to lead, manganese and zinc content of the rings, which may be related to pH. In conclusion, the variability between trees at each site suggests that dendroanalysis is a poor method for evaluating metal exposure at a large (site) scale. Tree ring metal content may be used to evaluate the metal uptake by individual trees but metal mobility in the stem makes it difficult to establish a reliable chronology.

Martin,R.; Naftel, S.; Macfie, S.; Jones, K.; Feng, H.; Trembley, C.

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Collective phase description of oscillatory convection  

SciTech Connect (OSTI)

We formulate a theory for the collective phase description of oscillatory convection in Hele-Shaw cells. It enables us to describe the dynamics of the oscillatory convection by a single degree of freedom which we call the collective phase. The theory can be considered as a phase reduction method for limit-cycle solutions in infinite-dimensional dynamical systems, namely, stable time-periodic solutions to partial differential equations, representing the oscillatory convection. We derive the phase sensitivity function, which quantifies the phase response of the oscillatory convection to weak perturbations applied at each spatial point, and analyze the phase synchronization between two weakly coupled Hele-Shaw cells exhibiting oscillatory convection on the basis of the derived phase equations.

Kawamura, Yoji, E-mail: ykawamura@jamstec.go.jp [Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001 (Japan)] [Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001 (Japan); Nakao, Hiroya [Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology, Tokyo 152-8552 (Japan)] [Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology, Tokyo 152-8552 (Japan)

2013-12-15T23:59:59.000Z

82

Stellar models with mixing length and T(tau) relations calibrated on 3D convection simulations  

E-Print Network [OSTI]

(abridged) The calculation of the thermal stratification in the superadiabatic layers of stellar models with convective envelopes is a long standing problem of stellar astrophysics, and has a major impact on predicted observational properties like radius and effective temperature. The Mixing Length Theory, almost universally used to model the superadiabatic convective layers, contains effectively one free parameter to be calibrated --alpha(ml)-- whose value controls the resulting effective temperature. Here we present the first self-consistent stellar evolution models calculated by employing the atmospheric temperature stratification, Rosseland opacities, and calibrated variable alpha(ml) (dependent on effective temperature and surface gravity) from a large suite of three-dimensional radiation hydrodynamics simulations of stellar convective envelopes and atmospheres for solar stellar composition (Trampedach et al. 2013). From our calculations (with the same composition of the radiation hydrodynamics simulatio...

Salaris, Maurizio

2015-01-01T23:59:59.000Z

83

Convective heat transfer inside passive solar buildings  

SciTech Connect (OSTI)

Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

1983-01-01T23:59:59.000Z

84

Convective heat transfer inside passive solar buildings  

SciTech Connect (OSTI)

Natural convection between spaces in a building which play a major role in energy transfer are discussed. Two situations are investigated: Convection through a single doorway into a remote room, and a convective loop in a two story house with a south sunspace where a north stairway serves as the return path. A doorway sizing equation is given for the single door case. Data from airflow monitoring in one two-story house and summary data for five others are presented. The nature of the airflow and design guidelines are presented.

Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

1983-11-01T23:59:59.000Z

85

Structure and evolution of a convective band MCS  

E-Print Network [OSTI]

circulation of the Mesoscale Convective Complex apparently aided in the formation of new lines of convection behind the primary convective line of the system. This process was repeated twice in the storm life cycle and led to multiple bands of convection...

Valdes-Manzanilla, Arturo

1995-01-01T23:59:59.000Z

86

Convective Cooling and Passive Stack Improvements in Motors (Presentation)  

SciTech Connect (OSTI)

This presentation discusses current research at NREL in convective cooling and passive stack improvements in motors.

Bennion, K.

2014-06-01T23:59:59.000Z

87

Estimation of Convection Loss from Paraboloidal Dish Cavity Receivers  

E-Print Network [OSTI]

presents new results from an investigation of natural and combined convection heat transfer from open in which force convection dominates can be clarified. 1. INTRODUCTION Convective heat transfer and numerical investigation of natural convection heat transfer has also been published in Taumoefolau et al

88

A FULL SCALE ROOM FOR THE EXPERIMENTAL STUDY OF INTERIOR BUILDING CONVECTIVE HEAT TRANSFER  

E-Print Network [OSTI]

air flow measurement. A water source heat pump provided chilled water to a fan-coil unit which in turn on volumetric air flow measurement and an overall room heat balance. Analysis was directed at results fromA FULL SCALE ROOM FOR THE EXPERIMENTAL STUDY OF INTERIOR BUILDING CONVECTIVE HEAT TRANSFER: DESIGN

89

Modeling convection in the Greenland Sea  

E-Print Network [OSTI]

A detailed examination of the development of a deep convection event observed in the Greenland Sea in 1988-89 is carried out through a combination of modeling, scale estimates, and data analysis. We develop a prognostic ...

Bhushan, Vikas

1998-01-01T23:59:59.000Z

90

Circulation and convection in the Irminger Sea  

E-Print Network [OSTI]

Aspects of the circulation and convection in the Irminger Sea are investigated using a variety of in-situ, satellite, and atmospheric reanalysis products. Westerly Greenland tip jet events are intense, small-scale wind ...

Våge, Kjetil

2010-01-01T23:59:59.000Z

91

Seismic Sounding of Convection in the Sun  

E-Print Network [OSTI]

Our Sun, primarily composed of ionized hydrogen and helium, has a surface temperature of 5777~K and a radius $R_\\odot \\approx 696,000$ km. In the outer $R_\\odot/3$, energy transport is accomplished primarily by convection. Using typical convective velocities $u\\sim100\\,\\rm{m\\,s^{-1}}$ and kinematic viscosities of order $10^{-4}$ m$^{2}$s$^{-1}$, we obtain a Reynolds number $Re \\sim 10^{14}$. Convection is thus turbulent, causing a vast range of scales to be excited. The Prandtl number, $Pr$, of the convecting fluid is very low, of order $10^{-7}$\\,--\\,$10^{-4}$, so that the Rayleigh number ($\\sim Re^2 Pr$) is on the order of $10^{21}\\,-\\,10^{24}$. Solar convection thus lies in extraordinary regime of dynamical parameters, highly untypical of fluid flows on Earth. Convective processes in the Sun drive global fluid circulations and magnetic fields, which in turn affect its visible outer layers ("solar activity") and, more broadly, the heliosphere ("space weather"). The precise determination of the depth of sola...

Hanasoge, Shravan; Sreenivasan, Katepalli R

2015-01-01T23:59:59.000Z

92

ARM - Midlatitude Continental Convective Clouds - Ultra High Sensitivity Aerosol Spectrometer(tomlinson-uhsas)  

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

Ultra High Sensitivity Aerosol Spectrometer (UHSASA) A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment. These files contain brightness temperatures observed at Purcell during MC3E. The measurements were made with a 5 channel (22.235, 23.035, 23.835, 26.235, 30.000GHz) microwave radiometer at one minute intervals. The results have been separated into daily files and the day of observations is indicated in the file name. All observations were zenith pointing. Included in the files are the time variables base_time and time_offset. These follow the ARM time conventions. Base_time is the number seconds since January 1, 1970 at 00:00:00 for the first data point of the file and time_offset is the offset in seconds from base_time.

Tomlinson, Jason; Jensen, Mike

93

ARM - Midlatitude Continental Convective Clouds Microwave Radiometer Profiler (jensen-mwr)  

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

A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment. These files contain brightness temperatures observed at Purcell during MC3E. The measurements were made with a 5 channel (22.235, 23.035, 23.835, 26.235, 30.000GHz) microwave radiometer at one minute intervals. The results have been separated into daily files and the day of observations is indicated in the file name. All observations were zenith pointing. Included in the files are the time variables base_time and time_offset. These follow the ARM time conventions. Base_time is the number seconds since January 1, 1970 at 00:00:00 for the first data point of the file and time_offset is the offset in seconds from base_time.

Jensen, Mike

94

ARM - Midlatitude Continental Convective Clouds Microwave Radiometer Profiler (jensen-mwr)  

SciTech Connect (OSTI)

A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment. These files contain brightness temperatures observed at Purcell during MC3E. The measurements were made with a 5 channel (22.235, 23.035, 23.835, 26.235, 30.000GHz) microwave radiometer at one minute intervals. The results have been separated into daily files and the day of observations is indicated in the file name. All observations were zenith pointing. Included in the files are the time variables base_time and time_offset. These follow the ARM time conventions. Base_time is the number seconds since January 1, 1970 at 00:00:00 for the first data point of the file and time_offset is the offset in seconds from base_time.

Jensen, Mike

2012-02-01T23:59:59.000Z

95

ARM - Midlatitude Continental Convective Clouds - Ultra High Sensitivity Aerosol Spectrometer(tomlinson-uhsas)  

SciTech Connect (OSTI)

Ultra High Sensitivity Aerosol Spectrometer (UHSASA) A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment. These files contain brightness temperatures observed at Purcell during MC3E. The measurements were made with a 5 channel (22.235, 23.035, 23.835, 26.235, 30.000GHz) microwave radiometer at one minute intervals. The results have been separated into daily files and the day of observations is indicated in the file name. All observations were zenith pointing. Included in the files are the time variables base_time and time_offset. These follow the ARM time conventions. Base_time is the number seconds since January 1, 1970 at 00:00:00 for the first data point of the file and time_offset is the offset in seconds from base_time.

Tomlinson, Jason; Jensen, Mike

2012-02-28T23:59:59.000Z

96

ARM - Midlatitude Continental Convective Clouds (jensen-sonde)  

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

A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment.

Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

97

ARM - Midlatitude Continental Convective Clouds (jensen-sonde)  

SciTech Connect (OSTI)

A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment.

Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

2012-01-19T23:59:59.000Z

98

Characterization of Fuego for laminar and turbulent natural convection heat transfer.  

SciTech Connect (OSTI)

A computational fluid dynamics (CFD) analysis is conducted for internal natural convection heat transfer using the low Mach number code Fuego. The flow conditions under investigation are primarily laminar, transitional, or low-intensity level turbulent flows. In the case of turbulent boundary layers at low-level turbulence or transitional Reynolds numbers, the use of standard wall functions no longer applies, in general, for wall-bounded flows. One must integrate all the way to the wall in order to account for gradients in the dependent variables in the viscous sublayer. Fuego provides two turbulence models in which resolution of the near-wall region is appropriate. These models are the v2-f turbulence model and a Launder-Sharma, low-Reynolds number turbulence model. Two standard geometries are considered: the annulus formed between horizontal concentric cylinders and a square enclosure. Each geometry emphasizes wall shear flow and complexities associated with turbulent or near turbulent boundary layers in contact with a motionless core fluid. Overall, the Fuego simulations for both laminar and turbulent flows compared well to measured data, for both geometries under investigation, and to a widely accepted commercial CFD code (FLUENT).

Francis, Nicholas Donald, Jr. (,; .)

2005-08-01T23:59:59.000Z

99

Final Report on Evaluating the Representation and Impact of Convective Processes in the NCAR Community Climate System Model  

SciTech Connect (OSTI)

Convection and clouds affect atmospheric temperature, moisture and wind fields through the heat of condensation and evaporation and through redistributions of heat, moisture and momentum. Individual clouds have a spatial scale of less than 10 km, much smaller than the grid size of several hundred kilometers used in climate models. Therefore the effects of clouds must be approximated in terms of variables that the model can resolve. Deriving such formulations for convection and clouds has been a major challenge for the climate modeling community due to the lack of observations of cloud and microphysical properties. The objective of our DOE CCPP project is to evaluate and improve the representation of convection schemes developed by PIs in the NCAR (National Center for Atmospheric Research) Community Climate System Model (CCSM) and study its impact on global climate simulations. • The project resulted in nine peer-reviewed publications and numerous scientific presentations that directly address the CCPP’s scientific objective of improving climate models. • We developed a package of improved convection parameterization that includes improved closure, trigger condition for convection, and comprehensive treatment of convective momentum transport. • We implemented the new convection parameterization package into several versions of the NCAR models (both coupled and uncoupled). This has led to 1) Improved simulation of seasonal migration of ITCZ; 2) Improved shortwave cloud radiative forcing response to El Niño in CAM3; 3) Improved MJO simulation in both uncoupled and coupled model; and 4) Improved simulation of ENSO in coupled model. • Using the dynamic core of CCM3, we isolated the dynamic effects of convective momentum transport. • We implemented mosaic treatment of subgrid-scale cloud-radiation interaction in CCM3.

X. Wu, G. J. Zhang

2008-04-23T23:59:59.000Z

100

Asteroseismic Diagnostics of Stellar Convective Cores  

E-Print Network [OSTI]

We present a detailed study of the small frequency separations as diagnostics of the mass of the convective core and evolutionary stage of solar-type stars. We demonstrate how the small separations can be combined to provide sensitive tests for the presence of convective overshoot at the edge of the core. These studies are focused on low degree oscillation modes, the only modes expected to be detected in distant stars. Using simulated data with realistic errors, we find that the mass of the convective core can be estimated to within 5% if the total stellar mass is known. Systematic errors arising due to uncertainty in the mass could be up to 20%. The evolutionary stage of the star, determined in terms of the central hydrogen abundance using our proposed technique, however, is much less sensitive to the mass estimate.

Anwesh Mazumdar; Sarbani Basu; Braxton L. Collier; Pierre Demarque

2006-08-16T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Convection and dynamo action in B stars  

E-Print Network [OSTI]

Main-sequence massive stars possess convective cores that likely harbor strong dynamo action. To assess the role of core convection in building magnetic fields within these stars, we employ the 3-D anelastic spherical harmonic (ASH) code to model turbulent dynamics within a 10 solar mass main-sequence (MS) B-type star rotating at 4 times the solar rate. We find that strong (900 kG) magnetic fields arise within the turbulence of the core and penetrate into the stably stratified radiative zone. These fields exhibit complex, time-dependent behavior including reversals in magnetic polarity and shifts between which hemisphere dominates the total magnetic energy.

Augustson, Kyle C; Toomre, Juri

2010-01-01T23:59:59.000Z

102

Convection in Arc Weld Pools Electromagnetic and surface tension forces are shown to  

E-Print Network [OSTI]

Convection in Arc Weld Pools Electromagnetic and surface tension forces are shown to dominate flow tension forces. It is shown that the electromag- netic and surface tension forces domi- nate the flow by experimental measurements of segrega- tion in the weld pool. It is also shown that the surface tension driven

Eagar, Thomas W.

103

Observed radar reflectivity in convectively coupled Kelvin and mixed Rossby-gravity waves  

E-Print Network [OSTI]

be measurable from surface gauges (>0.5 mm/hr). Addition- ally, the area of radar echo at each height of a normalized probability density function (PDF) of radar echo intensity at that level. Our analysis uses radarObserved radar reflectivity in convectively coupled Kelvin and mixed Rossby-gravity waves A. Swann

Yuter, Sandra

104

Nonlinear Thermal Transport and Brine Convection in First Year Sea Ice  

E-Print Network [OSTI]

Nonlinear Thermal Transport and Brine Convection in First Year Sea Ice M.J. McGuinness \\Lambda , H a programme recently set up to directly measure the thermal conductivity of young sea ice. An array of thermistors frozen into first­year Antarctic sea ice provides temperature against depth data, which is fitted

105

Simulation of Convection and Macrosegregation in a Large Steel Ingot  

E-Print Network [OSTI]

Simulation of Convection and Macrosegregation in a Large Steel Ingot J.P. GU and C. BECKERMANN Melt convection and macrosegregation in casting of a large steel ingot are numerically simulated. The simulation is based on a previously developed model for multicomponent steel solidification with melt convection

Beckermann, Christoph

106

Realistic Solar Surface Convection Simulations Robert F. Stein  

E-Print Network [OSTI]

Realistic Solar Surface Convection Simulations Robert F. Stein Michigan State University, East free simulations with re­ alistic physics of convection near the solar surface. We summarize solar convection is non­local. It is driven from a thin surface thermal boundary layer where radiative

Stein, Robert

107

The effect of convection on pulsational stability  

E-Print Network [OSTI]

A review on the current state of mode physics in classical pulsators is presented. Two, currently in use, time-dependent convection models are compared and their applications on mode stability are discussed with particular emphasis on the location of the Delta Scuti instability strip.

G. Houdek

2008-10-29T23:59:59.000Z

108

Laminar boundary layers in convective heat transport  

E-Print Network [OSTI]

We study Rayleigh-Benard convection in the high-Rayleigh-number and high-Prandtl-number regime, i.e., we consider a fluid in a container that is exposed to strong heating of the bottom and cooling of the top plate in the absence of inertia effects. While the dynamics in the bulk are characterized by a chaotic convective heat flow, the boundary layers at the horizontal container plates are essentially conducting and thus the fluid is motionless. Consequently, the average temperature exhibits a linear profile in the boundary layers. In this article, we rigorously investigate the average temperature and oscillations in the boundary layer via local bounds on the temperature field. Moreover, we deduce that the temperature profile is indeed essentially linear close to the horizontal container plates. Our results are uniform in the system parameters (e.g. the Rayleigh number) up to logarithmic correction terms. An important tool in our analysis is a new Hardy-type estimate for the convecting velocity field, which can be used to control the fluid motion in the layer. The bounds on the temperature field are derived with the help of local maximal regularity estimates for convection-diffusion equations.

Christian Seis

2012-12-12T23:59:59.000Z

109

Convective Instability of a Boundary Layer with  

E-Print Network [OSTI]

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

Conrad, Clint

110

Solar Dynamics, Rotation, Convection and Overshoot  

E-Print Network [OSTI]

We discuss recent observational, theoretical and modeling progress made in understanding the Sun's internal dynamics, including its rotation, meridional flow, convection and overshoot. Over the past few decades, substantial theoretical and observational effort has gone into appreciating these aspects of solar dynamics. A review of these observations, related helioseismic methodology and inference and computational results in relation to these problems is undertaken here.

Hanasoge, S; Roth, M; Schou, J; Schuessler, M; Thompson, M J

2015-01-01T23:59:59.000Z

111

Convective and absolute instabilities in eccentric Taylor  

E-Print Network [OSTI]

Convective and absolute instabilities in eccentric Taylor Laboratoire de mécanique des fluides et d and absolute instabilities in Taylor-Couette-Poiseuille flow Benoît PIER Laboratoire de mécanique des fluides flow type often disrupt oil-well drilling By implementing a detailed instability analysis, the dynamics

Shyamasundar, R.K.

112

Solar MagnetoConvection David J. Bercik  

E-Print Network [OSTI]

Solar Magneto­Convection David J. Bercik Dept. of Physics and Astronomy, Michigan State University, Michigan State University, East Lansing, MI 48824, U.S.A. š Ake Nordlund Theoretical Astrophysics Center, �ster Voldgade 3, 1350 Copenhagen K, Denmark Robert F. Stein Dept. of Physics and Astronomy, Michigan

Stein, Robert

113

CONVECTION THEORY AND SUB-PHOTOSPHERIC STRATIFICATION  

SciTech Connect (OSTI)

As a preliminary step toward a complete theoretical integration of three-dimensional compressible hydrodynamic simulations into stellar evolution, convection at the surface and sub-surface layers of the Sun is re-examined, from a restricted point of view, in the language of mixing-length theory (MLT). Requiring that MLT use a hydrodynamically realistic dissipation length gives a new constraint on solar models. While the stellar structure which results is similar to that obtained by Yale Rotational Evolution Code (Guenther et al.; Bahcall and Pinsonneault) and Garching models (Schlattl et al.), the theoretical picture differs. A new quantitative connection is made between macro-turbulence, micro-turbulence, and the convective velocity scale at the photosphere, which has finite values. The 'geometric parameter' in MLT is found to correspond more reasonably with the thickness of the superadiabatic region (SAR), as it must for consistency in MLT, and its integrated effect may correspond to that of the strong downward plumes which drive convection (Stein and Nordlund), and thus has a physical interpretation even in MLT. If we crudely require the thickness of the SAR to be consistent with the 'geometric factor' used in MLT, there is no longer a free parameter, at least in principle. Use of three-dimensional simulations of both adiabatic convection and stellar atmospheres will allow the determination of the dissipation length and the geometric parameter (i.e., the entropy jump) more realistically, and with no astronomical calibration. A physically realistic treatment of convection in stellar evolution will require substantial additional modifications beyond MLT, including nonlocal effects of kinetic energy flux, entrainment (the most dramatic difference from MLT found by Meakin and Arnett), rotation, and magnetic fields.

Arnett, David; Meakin, Casey; Young, Patrick A., E-mail: darnett@as.arizona.ed, E-mail: casey.meakin@gmail.co, E-mail: patrick.young.1@asu.ed [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

2010-02-20T23:59:59.000Z

114

Measurements of Sea Surface Height Variability in the Eastern South Atlantic from Pressure Sensor-Equipped Inverted Echo Sounders: Baroclinic and Barotropic  

E-Print Network [OSTI]

Variability in sea surface height (SSH) can be decomposed into two contributions: one from changes in mass in the water column (barotropic) and the other from purely steric changes (baroclinic). Both contributions can be ...

Baker-Yeboah, Sheekela

115

Healthy transportation - healthy communities: developing objective measures of built-environment using GIS and testing significance of pedestrian variables on walking to transit  

E-Print Network [OSTI]

-Transportation-Air Quality (LUTRAQ) study for Portland, Oregon (1000 Friends of Oregon, 1997) looked at the impact of specific built- environment variables on travel. The built-environment variables such as ease of street crossings, sidewalk continuity, local street... twenty-one pedestrian indices (Allan, 2001; Bandara et al., 1994; Bradshaw, 1993; Dixon 1996; USDOT; Landis et al., 2001; City of Ft. Collins, 2002; Khisty, 1994; Moudon, 2001; Moudon et al., 2002; City of Portland, 1998; Wellar; Gallin, 2001; Portland...

Maghelal, Praveen Kumar

2009-05-15T23:59:59.000Z

116

Evaluating the Representation and Impact of Convective Processes in the NCAR’s Community Climate System Model  

SciTech Connect (OSTI)

Convection and clouds affect atmospheric temperature, moisture and wind fields through the heat of condensation and evaporation and through redistributions of heat, moisture and momentum. Individual clouds have a spatial scale of less than 10 km, much smaller than the grid size of several hundred kilometers used in climate models. Therefore the effects of clouds must be approximated in terms of variables that the model can resolve. Deriving such formulations for convection and clouds has been a major challenge for the climate modeling community due to the lack of observations of cloud and microphysical properties. The objective of our DOE CCPP project is to evaluate and improve the representation of convection schemes developed by PIs in the NCAR (National Center for Atmospheric Research) Community Climate System Model (CCSM) and study its impact on global climate simulations.

Xiaoqing Wu

2008-07-31T23:59:59.000Z

117

EFFECTS OF ASYMMETRIC FLOWS IN SOLAR CONVECTION ON OSCILLATION MODES  

SciTech Connect (OSTI)

Many helioseismic measurements suffer from substantial systematic errors. A particularly frustrating one is that time-distance measurements suffer from a large center to limb effect which looks very similar to the finite light travel time, except that the magnitude depends on the observable used and can have the opposite sign. This has frustrated attempts to determine the deep meridional flow in the solar convection zone, with Zhao et al. applying an ad hoc correction with little physical basis to correct the data. In this Letter, we propose that part of this effect can be explained by the highly asymmetrical nature of the solar granulation which results in what appears to the oscillation modes as a net radial flow, thereby imparting a phase shift on the modes as a function of observing height and thus heliocentric angle.

Baldner, Charles S.; Schou, Jesper, E-mail: baldner@stanford.edu [W.W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States)

2012-11-20T23:59:59.000Z

118

Development and evaluation of a convection scheme for use in climate models  

SciTech Connect (OSTI)

Cumulus convection is a key process in controlling the water vapor content of the atmosphere, which is in turn the largest feedback mechanism for climate change in global climate models. Yet scant attention has been paid to designing convective representations that attempt to handle water vapor with fidelity, and even less to evaluating their performance. Here the authors attempt to address this deficiency by designing a representation of cumulus convection with close attention paid to convective water fluxes and by subjecting the scheme to rigorous tests using sounding array data. The authors maintain that such tests, in which a single-column model is forced by large-scale processes measured by or inferred from the sounding data, must be carried out over a period at least as long as the radiative-subsidence timescale--about 30 days--governing the water vapor adjustment time. The authors also argue that the observed forcing must be preconditioned to guarantee integral enthalpy conservation, else errors in the single-column prediction may be falsely attributed to convective schemes. Optimization of the new scheme`s parameters is performed using one month of data from the intensive flux array operating during the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment, with the aid of the adjoint of the linear tangent of the single-column model. Residual root-mean-square errors, after optimization, are about 15% in relative humidity and .8 K in temperature. It is difficult to reject the hypothesis that the residual errors are due to noise in the forcing. Evaluation of the convective scheme is performed using Global Atmospheric Research Program Atlantic Tropical Experiment data. The performance of the scheme is compared to that of a few other schemes used in current climate models. It is also shown that a vertical resolution better than 50 mb in pressure is necessary for accurate prediction of atmospheric water vapor.

Emanuel, K.A. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Program for Atmospheres, Oceans, and Climate] [Massachusetts Inst. of Tech., Cambridge, MA (United States). Program for Atmospheres, Oceans, and Climate; Zivkovic-Rothman, M. [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States)] [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States)

1999-06-01T23:59:59.000Z

119

Thermocapillary convection induced by laser surface heating  

SciTech Connect (OSTI)

Thermocapillary convection was excited by a laser source in experiments on molten paraffin. The parameters of the resultant flow were determined. The nature of the flow was demonstrated to correspond to shear-driven boundary-layer flow at high Reynolds numbers. Correlation dependences of the flow velocity of the melt and its temperature in the surface region were derived theoretically and were shown to agree with the experimental results. When the size of the laser spot was much less than the characteristic convection scales, three regions of flow of the melt could be distinguished: a viscous surface boundary layer, a stagnation zone under the laser spot, and a large-scale region of flow with a homogeneous temperature distribution. (interaction of laser radiation with matter. laser plasma)

Gladush, G G; Drobyazko, S V; Likhanskii, V V; Loboiko, A I; Senatorov, Yu M [State Research Center of Russian Federation 'Troitsk Institute for Innovation and Fusion Research', Troitsk, Moscow Region (Russian Federation)

1998-05-31T23:59:59.000Z

120

Laser induced natural convection and thermophoresis  

SciTech Connect (OSTI)

The influence of axial laser volumetric heating and forced convection on the motion of aerosol particles in a vertical tube has been studied. The asymptotic case of constant wall temperature provides simple temperature and velocity profiles that determine the convection and thermophoretic motion of small aerosol particles. For the case in which the flow (in the absence of laser heating) is downward, the laser heating induces upward buoyant motion near the tube center. When the laser heating is taken to be constant (a small absorption limit), a velocity profile may be found that will minimize the distance over which particles are deposited on the wall. Such an observation may have some bearing on the manufacture of preforms from which optical fibers are drawn.

Wang, C.Y.; Cipolla, J.; Morse, T.F.

1983-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Cataclysmic Variables  

E-Print Network [OSTI]

Cataclysmic variables are binary stars in which a relatively normal star is transferring mass to its compact companion. This interaction gives rise to a rich range of behaviour, of which the most noticeable are the outbursts that give the class its name. Novae belong to the class, as do the less well known dwarf novae and magnetic systems. Novae draw their energy from nuclear reactions, while dwarf novae rely on gravity to power their smaller eruptions. All the different classes of cataclysmic variable can be accommodated within a single framework and this article will describe the framework, review the properties of the main types of system and discuss models of the outbursts and of the long-term evolution.

Robert Connon Smith

2007-01-23T23:59:59.000Z

122

Magneto-convection in a sunspot umbra  

E-Print Network [OSTI]

Results from a realistic simulation of 3D radiative magneto-convection in a strong background magnetic field corresponding to the conditions in sunspot umbrae are shown. The convective energy transport is dominated by narrow upflow plumes with adjacent downflows, which become almost field-free near the surface layers. The strong external magnetic field forces the plumes to assume a cusp-like shape in their top parts, where the upflowing plasma loses its buoyancy. The resulting bright features in intensity images correspond well (in terms of brightness, size, and lifetime) to the observed umbral dots in the central parts of sunspot umbrae. Most of the simulated umbral dots have a horizontally elongated form with a central dark lane. Above the cusp, most plumes show narrow upflow jets, which are driven by the pressure of the piled-up plasma below. The large velocities and low field strengths in the plumes are effectively screened from spectroscopic observation because the surfaces of equal optical depth are locally elevated, so that spectral lines are largely formed above the cusp. Our simulations demonstrate that nearly field-free upflow plumes and umbral dots are a natural result of convection in a strong, initially monolithic magnetic field.

M. Schuessler; A. Voegler

2006-03-03T23:59:59.000Z

123

Convective Dynamo Simulation with a Grand Minimum  

E-Print Network [OSTI]

The global-scale dynamo action achieved in a simulation of a Sun-like star rotating at thrice the solar rate is assessed. The 3-D MHD Anelastic Spherical Harmonic (ASH) code, augmented with a viscosity minimization scheme, is employed to capture convection and dynamo processes in this G-type star. The simulation is carried out in a spherical shell that encompasses 3.8 density scale heights of the solar convection zone. It is found that dynamo action with a high degree of time variation occurs, with many periodic polarity reversals occurring roughly every 6.2 years. The magnetic energy also rises and falls with a regular period. The magnetic energy cycles arise from a Lorentz-force feedback on the differential rotation, whereas the processes leading to polarity reversals are more complex, appearing to arise from the interaction of convection with the mean toroidal fields. Moreover, an equatorial migration of toroidal field is found, which is linked to the changing differential rotation, and potentially to a no...

Augustson, Kyle; Miesch, Mark; Toomre, Juri

2015-01-01T23:59:59.000Z

124

1234 VOLUME 42J O U R N A L O F A P P L I E D M E T E O R O L O G Y Radiative and Microphysical Characteristics of Deep Convective Systems in the  

E-Print Network [OSTI]

precipitation radar and Geostationary Meteorological Satellite infrared radiometer measurements are used%. In cases in which the convective available potential energy (CAPE) is large, deep convective clouds roles in producing the high albedos of tropical anvil clouds. A comparison of the radiative heating

125

Meridional Circulation in Solar and Stellar Convection Zones  

E-Print Network [OSTI]

We present a series of 3-D nonlinear simulations of solar-like convection, carried out using the Anelastic Spherical Harmonic (ASH) code, that are designed to isolate those processes that drive and shape meridional circulations within stellar convection zones. These simulations have been constructed so as to span the transition between solar-like differential rotation (fast equator/slow poles) and ``anti-solar' differential rotation (slow equator/fast poles). Solar-like states of differential rotation, arising when convection is rotationally constrained, are characterized by a very different convective Reynolds stress than anti-solar regimes, wherein convection only weakly senses the Coriolis force. We find that the angular momentum transport by convective Reynolds stress plays a central role in establishing the meridional flow profiles in these simulations. We find that the transition from single-celled to multi-celled meridional circulation profiles in strong and weak regimes of rotational constraint is lin...

Featherstone, Nicholas A

2015-01-01T23:59:59.000Z

126

What Goes Up Must Come Down: The Lifecycle of Convective Clouds (492nd Brookhaven Lecture)  

SciTech Connect (OSTI)

Some clouds look like cotton balls and others like anvils. Some bring rain, some snow and sleet, and others, just shade. But, whether big and billowy or dark and stormy, clouds affect far more than the weather each day. Armed with measurements of clouds’ updrafts and downdrafts—which resemble airflow in a convection oven—and many other atmospheric interactions, scientists from Brookhaven Lab and other institutions around the world are developing models that are crucial for understanding Earth’s climate and forecasting future climate change. During his lecture, Dr. Jensen provides an overview of the importance of clouds in the Earth’s climate system before explaining how convective clouds form, grow, and dissipate. His discussion includes findings from the Midlatitude Continental Convective Clouds Experiment (MC3E), a major collaborative experiment between U.S. Department of Energy (DOE) and NASA scientists to document precipitation, clouds, winds, and moisture in 3-D for a holistic view of convective clouds and their environment.

Jensen, Michael [BNL Environmental Sciences

2014-02-19T23:59:59.000Z

127

Chapter 18: Variable Frequency Drive Evaluation Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures: September 2011 Â… December 2014  

Energy Savers [EERE]

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 Data Center Home Page on Delicious RankCombustion |Energyon ArmedWaste andAccessCO2 Injection Begins8: Variable Frequency Drive Evaluation

128

Meridional circulation dynamics from 3D MHD global simulations of solar convection  

E-Print Network [OSTI]

The form of the solar meridional circulation is a very important ingredient for mean field flux transport dynamo models. Yet a shroud of mystery still surrounds this large-scale flow, given that its measurement using current helioseismic techniques is challenging. In this work we use results from 3D global simulations of solar convection to infer the dynamical behavior of the established meridional circulation. We make a direct comparison between the meridional circulation that arises in these simulations and the latest observations. Based on our results we argue that there should be an equatorward flow at the base of the convection zone at mid latitudes, below the current maximum depth helioseismic measures can probe (0.75 R). We also provide physical arguments to justify this behaviour. The simulations indicate that the meridional circulation undergoes substantial changes in morphology as the magnetic cycle unfolds. We close by discussing the importance of these dynamical changes for current methods of obse...

Passos, Dario; Miesch, Mark

2015-01-01T23:59:59.000Z

129

ARM - Evaluation Product - Convective Vertical Velocity  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcal Documentation(AVIRIS) ProductsAirborne Visible/Infrared Imaging SpectrometerAlgorithmProductsConvective

130

Air convection noise of pencil-beam interferometer for long trace profiler  

E-Print Network [OSTI]

Air Convection Noise of Pencil-beam Interferometer for Longwe investigate the effect of air convection on laser-beamshown that the NPD spectra due to air convection have a very

Yashchuk, Valeriy V.; Irick, Steve C.; MacDowell, Alastair A.; McKinney, Wayne R.; Takacs, Peter Z.

2006-01-01T23:59:59.000Z

131

The QBO's influence on lightning production and deep convection in the tropics  

E-Print Network [OSTI]

) flash densities and ten years (1998-2007) of TRMM Precipitation Radar (PR) deep convective and stratiform rainfall and convective echo top heights are analyzed. The QBO can be linked to deep convection through two hypothesized mechanisms: 1) modulation...

Hernandez, Celina Anne

2009-05-15T23:59:59.000Z

132

Application of the 85 GHz ice scattering signature to a global study of mesoscale convective systems  

E-Print Network [OSTI]

It has long been observed that tropical convection tends to cluster, organizing into multicellular mesoscale convective systems (MCS), In convective towers, updrafts on the order of 10 m s-I favor the formation of large, precipitation-sized ice...

Devlin, Karen Irene

1995-01-01T23:59:59.000Z

133

Investigation of combined free and forced convection in a 2 x 6 rod bundle during controlled flow transients  

SciTech Connect (OSTI)

An experimental study was performed to obtain local fluid velocity and temperature measurements in the mixed (combined free and forced) convection regime for specific flow coastdown transients. A brief investigation of steady-state flows for the purely free-convection regime was also completed. The study was performed using an electrically heated 2 x 6 rod bundle contained in a flow housing. In addition a transient data base was obtained for evaluating the COBRA-WC thermal-hydraulic computer program (a modified version of the COBRA-IV code).

Bates, J.M.; Khan, E.U.

1980-10-01T23:59:59.000Z

134

Gravity Waves in Shear and Implications for Organized Convection  

E-Print Network [OSTI]

Gravity Waves in Shear and Implications for Organized Convection Samuel N. Stechmann Department, Los Angeles, CA 90095­1555. E-mail: stechmann@math.ucla.edu #12;ABSTRACT It is known that gravity, the gravity waves can create a more favorable environment on one side of preexisting convection than the other

Stechmann, Samuel N.

135

EXPERIMENTAL INVESTIGATION OF BOILING HEAT CONVECTION IN A FRACTURE  

E-Print Network [OSTI]

EXPERIMENTAL INVESTIGATION OF BOILING HEAT CONVECTION IN A FRACTURE A REPORT SUBMITTED between heat conduction and heat convection with boiling flow in a rock fracture. An experimental coefficient. This coefficient is the proportionality factor between the heat flux to a fracture surface

Stanford University

136

UNCORRECTED Grid geometry effects on convection in ocean climate models  

E-Print Network [OSTI]

UNCORRECTED PROOF Grid geometry effects on convection in ocean climate models: a conceptual study is the 12 improvement of convection parameterization schemes, but the question of grid geometry also plays to an at- 14 mosphere model. Such ocean climate models have mostly structured, coarsely resolved grids. 15

Kuhlbrodt, Till

137

FLUCTUATIONS NEAR THE CONVECTIVE INSTABILITY IN A CHOLESTERIC LIQUID CRYSTAL  

E-Print Network [OSTI]

. For sufficiently strong heating, it is pos- sible for the buoyancy force to overcome the vis- cous shear forces convective pour une certaine valeur critique. A cause du couplage de modes induit par la force extérieure, la, drives the system into convective instability. It is found that, because of the mode coupling induced

Boyer, Edmond

138

Drainage induced convection rolls in foams (revised version)  

E-Print Network [OSTI]

, where soap solution is added to the foam at constant flow rate, the irregular motion in the beer glass results for convection in quasi two-dimensional foams (monolayers of bubbles between two glass platesDrainage induced convection rolls in foams (revised version) S. Hutzler, S.J. Cox*, E. Janiaud

Cox, Simon

139

Journal of Crystal Growth 193 (1998) 219--229 Visualization of convection in a simulated gradient freeze cell  

E-Print Network [OSTI]

horizontal cross sections of the cell. Flow velocities were measured via particle displacement tracking. The acceler- ation needed to obtain uniform doping was differ- ent for two different centrifuge arm lengths in order to visualize convection. Particle dis- placement tracking velocimetry (PDTV) was used

Regel, Liya L.

140

On the practice of dichotomization of quantitative variables  

E-Print Network [OSTI]

The authors examine the practice of dichotomization of quantitative measures, wherein relationships among variables are examined after 1 or more variables have been converted to dichotomous variables by splitting the sample ...

MacCallum, R. C.; Zhang, S.; Preacher, K. J.; Rucker, D. D.

2002-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Frictional heating and convective cooling of polycrystalline diamond drag tools during rock cutting  

SciTech Connect (OSTI)

A numerical-analytical model is developed to predict temperatures in stud-mounted polycrystalline diamond compact (PDC) drag tools during rock cutting. Experimental measurements of the convective heat transfer coefficient for PDC cutters are used in the model to predict temperatures under typical drilling conditions with fluid flow. The analysis compares favorably with measurements of frictional temperatures in controlled cutting tests on Tennessee marble. It is shown that mean cutter wearflat temperatures can be maintained below the critical value of 750{sup 0}C only under conditions of low friction at the cutter/rock interface. This is true, regardless of the level of convective cooling. In fact, a cooling limit is established above which increases in convective cooling do not further reduce cutter temperatures. The ability of liquid drilling fluids to reduce interface friction is thus shown to be far more important in preventing excessive temperatures than their ability to provide cutter cooling. Due to the relatively high interface friction developed under typical air drilling conditions, it is doubtful that temperatures can be kept subcritical at high rotary speeds in some formations when air is employed as the drilling fluid, regardless of the level of cooling achieved.

Ortega, A.; Glowka, D.A.

1982-01-01T23:59:59.000Z

142

Natural convection heat transfer for a staggered array of heated, horizontal cylinders within a rectangular enclosure  

SciTech Connect (OSTI)

This thesis presents the results of an experimental investigation of natural convection heat transfer in a staggered array of heated cylinders, oriented horizontally within a rectangular enclosure. The main purpose of this research was to extend the knowledge of heat transfer within enclosed bundles of spent nuclear fuel rods sealed within a shipping or storage container. This research extends Canaan`s investigation of an aligned array of heated cylinders that thermally simulated a boiling water reactor (BWR) spent fuel assembly sealed within a shipping or storage cask. The results are presented in terms of piecewise Nusselt-Rayleigh number correlations of the form Nu = C(Ra){sup n}, where C and n are constants. Correlations are presented both for individual rods within the array and for the array as a whole. The correlations are based only on the convective component of the heat transfer. The radiative component was calculated with a finite-element code that used measured surface temperatures, rod array geometry, and measured surface emissivities as inputs. The correlation results are compared to Canaan`s aligned array results and to other studies of natural convection in horizontal tube arrays.

Triplett, C.E.

1996-12-01T23:59:59.000Z

143

Late Holocene Radiocarbon Variability in Northwest Atlantic Slope Waters  

SciTech Connect (OSTI)

Deep-sea gorgonian corals secrete a 2-part skeleton of calcite, derived from dissolved inorganic carbon at depth, and gorgonin, derived from recently fixed and exported particulate organic matter. Radiocarbon contents of the calcite and gorgonin provide direct measures of seawater radiocarbon at depth and in the overlying surface waters, respectively. Using specimens collected from Northwest Atlantic slope waters, we generated radiocarbon records for surface and upper intermediate water layers spanning the pre- and post bomb-{sup 14}C eras. In Labrador Slope Water (LSW), convective mixing homogenizes the pre-bomb {Delta}{sup 14}C signature (-67 {+-} 4{per_thousand}) to at least 1000 m depth. Surface water bomb-{sup 14}C signals were lagged and damped (peaking at {approx} +45{per_thousand} in the early 1980s) relative to other regions of the northwest Atlantic, and intermediate water signals were damped further. Off southwest Nova Scotia, the vertical gradient in {Delta}{sup 14}C is much stronger. In surface water, pre-bomb {Delta}{sup 14}C averaged -75 {+-} 5{per_thousand}. At 250-475 m depth, prebomb {Delta}{sup 14}C oscillated quasi-decadally between -80 and -100{per_thousand}, likely reflecting interannual variability in the presence of Labrador Slope Water vs. Warm Slope Water (WSW). Finally, subfossil corals reveal no systematic changes in vertical {Delta}{sup 14}C gradients over the last 1200 years.

Sherwood, O; Edinger, E; Guilderson, T P; Ghaleb, B; Risk, M J; Scott, D B

2008-08-15T23:59:59.000Z

144

The development of convective instability in relation to convective activity and synoptic systems in AVE IV  

E-Print Network [OSTI]

700 mb 500 mb 300 mb 100 mb 1. 8 2 54 3. 1' 6. 2 3. 8 5 64 7 5 15. 0 RMS Direction Error RNS ~Seed Error -1 -1 0. 5ms l. oms -1 -1 0. 8 m s 2. 0 m s -1 -1 10ms 3. 8ms -1 -1 2. 0 m s 5. 7 m s The rawinsonde data were supplemented by hourly... of Co ttee) 4' (Member) N. I (Member) (Head of Department) August 1979 ABSTRACT Tha Development of Convective Instability in Relation to ConVectiVe Activity and Synoptic Systems in AVE 1V, (August 1979$ James Gregory Davis, B. S. , Texas A&M...

Davis, James Gregory

1979-01-01T23:59:59.000Z

145

Divergent subcritical convection in magnetized plasma from asymmetric sourcing  

SciTech Connect (OSTI)

Asymmetric particle and heat sourcing in a plasma confined in a closed magnetic field line configuration results in convection cells, as is well known. This phenomenon occurs even if the sourcing on average produces density and temperature profiles that are subcritical, i.e., magnetohydrodynamically stable to interchange modes. Such subcritical convection is expected to be small compared to the convection from supercritical driving for which the system is interchange unstable. The ratio of subcritical to supercritical convection is expected to scale as the inverse Reynolds numbers (for large Reynolds numbers). It is shown that this ratio is, in fact, considerably larger. As marginal stability is approached, the subcritical convection grows from very small to almost the unstable convection size, i.e., of order unity. This effect may be similar to why a driven, damped harmonic oscillator increases in amplitude as resonance is approached. A numerical simulation is done to demonstrate this effect. It is also shown that transport from the large convection can be substantial.

Adler, D.T.; Hassam, A.B. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)

2005-06-15T23:59:59.000Z

146

The Mid-Latitude Continental Convective Clouds Experiment (MC3E)  

SciTech Connect (OSTI)

The Midlatitude Continental Convective Cloud Experiment (MC3E) will take place in central Oklahoma during the April-May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy Atmospheric Radition Measurement Program and the National Aeronautics and Space Administration's (NASA) Global Precipitation Measurement (GPM) mission Ground Validation program. The Intensive Observation Period leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall observations over land that have never before been available. Several different components of convective processes tangible to the convective parameterization problem are targeted such as, pre-convective environment and convective initiation, updraft / downdraft dynamics, condensate transport and detrainment, precipitation and cloud microphysics, influence on the environment and radiation and a detailed description of the large-scale forcing. MC3E will use a new multi-scale observing strategy with the participation of a network of distributed sensors (both passive and active). The approach is to document in 3-D not only the full spectrum of precipitation rates, but also clouds, winds and moisture in an attempt to provide a holistic view of convective clouds and their feedback with the environment. A goal is to measure cloud and precipitation transitions and environmental quantities that are important for satellite retrieval algorithms, convective parameterization in large-scale models and cloud-resolving model simulations. This will be accomplished through the deployment of several different elements that complement the existing (and soon to become available) ARM facilities: a network of radiosonde stations, NASA scanning multi-frequency/parameter radar systems at three different frequencies (Ka/Ku/S), high-altitude remote sensing and in situ aircraft, wind profilers and a network of surface disdrometers. In addition to these special MC3E instruments, there will be important new instrumentation deployed by DOE at the ARM site including: 3 networked scanning X-band radar systems, a C-band scanning radar, a dual wavelength (Ka/W) scanning cloud radar, a Doppler lidar and upgraded vertically pointing millimeter cloud radar (MMCR) and micropulse lidar (MPL).To fully describe the properties of precipitating cloud systems, both in situ and remote sensing airborne observations are necessary. The NASA GPM-funded University of North Dakota (UND) Citation will provide in situ observations of precipitation-sized particles, ice freezing nuclei and aerosol concentrations. As a complement to the UND Citation's in situ observations, the NASA ER-2 will provide a high altitude satellite simulator platform that carrying a Ka/Ku band radar and passive microwave radiometers (10-183 GHZ).

Petersen,W.; Jensen,M.; Genio, A. D.; Giangrande, S.; Heymsfield, A.; Heymsfield, G.; Hou, A.; Kollias, P.; Orr, B.; Rutledge, S.; Schwaller, M.; Zipser, E.

2010-03-15T23:59:59.000Z

147

Final Technical Report for "Radiative Heating Associated with Tropical Convective Cloud Systems: Its Importance at Meso and Global Scales"  

SciTech Connect (OSTI)

Heating associated with tropical cloud systems drive the global circulation. The overall research objectives of this project were to i) further quantify and understand the importance of heating in tropical convective cloud systems with innovative observational techniques, and ii) use global models to determine the large-scale circulation response to variability in tropical heating profiles, including anvil and cirrus cloud radiative forcing. The innovative observational techniques used a diversity of radar systems to create a climatology of vertical velocities associated with the full tropical convective cloud spectrum along with a dissection of the of the total heating profile of tropical cloud systems into separate components (i.e., the latent, radiative, and eddy sensible heating). These properties were used to validate storm-scale and global climate models (GCMs) and were further used to force two different types of GCMs (one with and one without interactive physics). While radiative heating was shown to account for about 20% of the total heating and did not have a strong direct response on the global circulation, the indirect response was important via its impact on convection, esp. in how radiative heating impacts the tilt of heating associated with the Madden-Julian Oscillation (MJO), a phenomenon that accounts for most tropical intraseasonal variability. This work shows strong promise in determining the sensitivity of climate models and climate processes to heating variations associated with cloud systems.

Schumacher, Courtney

2012-12-13T23:59:59.000Z

148

Numerical and Experimental Modeling of Natural Convection for a Cryogenic Prototype of a Titan  

E-Print Network [OSTI]

in Sutherland's law D = diameter g = gravitation acceleration h = convection coefficient k = thermal

Colonius, Tim

149

Convective heat transfer characteristics of China RP-3 aviation kerosene at supercritical pressure  

E-Print Network [OSTI]

Convective heat transfer characteristics of China RP-3 aviation kerosene at supercritical pressure Keywords: Supercritical pressure Aviation kerosene Convective heat transfer Numerical study a b s t r a c convective in kerosene pipe flow is complicated. Here the convective heat transfer characteristics of China

Guo, Zhixiong "James"

150

PHYSICS OF FLUIDS 25, 044105 (2013) Onset of buoyancy-driven convection in Cartesian  

E-Print Network [OSTI]

the onset of buoyancy-driven convection relevant to subsurface carbon dioxide sequestration in confined

Firoozabadi, Abbas

151

Multiscale eddy simulation for moist atmospheric convection: Preliminary investigation  

SciTech Connect (OSTI)

A multiscale computational framework is designed for simulating atmospheric convection and clouds. In this multiscale framework, large eddy simulation (LES) is used to model the coarse scales of 100 m and larger, and a stochastic, one-dimensional turbulence (ODT) model is used to represent the fine scales of 100 m and smaller. Coupled and evolving together, these two components provide a multiscale eddy simulation (MES). Through its fine-scale turbulence and moist thermodynamics, MES allows coarse grid cells to be partially cloudy and to encompass cloudy–clear air mixing on scales down to 1 m; in contrast, in typical LES such fine-scale processes are not represented or are parameterized using bulk deterministic closures. To illustrate MES and investigate its multiscale dynamics, a shallow cumulus cloud field is simulated. The fine-scale variability is seen to take a plausible form, with partially cloudy grid cells prominent near cloud edges and cloud top. From earlier theoretical work, this mixing of cloudy and clear air is believed to have an important impact on buoyancy. However, contrary to expectations based on earlier theoretical studies, the mean statistics of the bulk cloud field are essentially the same in MES and LES; possible reasons for this are discussed, including possible limitations in the present formulation of MES. One difference between LES and MES is seen in the coarse-scale turbulent kinetic energy, which appears to grow slowly in time due to incoherent stochastic fluctuations in the buoyancy. This and other considerations suggest the need for some type of spatial and/or temporal filtering to attenuate undersampling of the stochastic fine-scale processes.

Stechmann, Samuel N., E-mail: stechmann@wisc.edu [Department of Mathematics, University of Wisconsin-Madison (United States); Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison (United States)

2014-08-15T23:59:59.000Z

152

Vertical profiles of radar reflectivity of convective cells in tropical and mid-latitude mesoscale convective systems  

E-Print Network [OSTI]

of the radar beam for the NCAR CP-3 and CP-4 Doppler radars and the NOAA/TOGA Doppler radar as a function of beamwidth 3 Maximum ref lectivity at selected heights and the range to the closest radar, at 4. 4 km, for the convective cells from the 10-11 June... Maximum ref lectivity at selected heights and the range to the NOAA/TOGA Doppler radar, at 3. 9 km, for the convective cells from the 2 December 1988 monsoon case 21 21 51 56 63 70 76 Table 8 As in Table 7, except for the convective cells from...

Lutz, Kurt Reed

1992-01-01T23:59:59.000Z

153

Compressional wave character in gassy, near-surface sediments in southern Louisiana determined from variable frequency cross-well, borehole logging, and surface seismic measurements  

SciTech Connect (OSTI)

Velocity and attenuation data were used to test theoretical equations describing the frequency dependence of compressional wave velocity and attenuation through gas-rich sediments in coastal Louisiana. The cross-well data were augmented with velocities derived from a nearby seismic refraction station using a low-frequency source. Energy at 1 and 3 kHz was successfully transmitted over distances from 3.69 to 30 m; the 5 and 7-kHz data were obtained only at distances up to 20 m. Velocity tomograms were constructed for one borehole pair and covered a depth interval of 10--50 m. Results from the tomographic modeling indicate that gas-induced low velocities are present to depths of greater than 40 m. Analysis of the velocity dispersion suggests that gas-bubble resonance must be greater than 7 kHz, which is above the range of frequencies used in the experiment. Washout of the boreholes at depths above 15 m resulted in a degassed zone containing velocities higher than those indicated in both nearby refraction and reflection surveys. Velocity and attenuation information were obtained for a low-velocity zone centered at a depth of approximately 18 m. Measured attenuations of 1.57, 2.95, and 3.24 dB/m for the 3-, 5-, and 7-kHz signals, respectively, were modeled along with the velocity data using a silt-clay sediment type. Density and porosity data for the model were obtained from the geophysical logs; the bulk and shear moduli were estimated from published relationships. Modeling results indicate that gas bubbles measuring 1 mm in diameter occupy at least 25% to 35% of the pore space.

Thompson, M.D.; McGinnis, L.D.; Wilkey, P.L. [Argonne National Lab., IL (United States); Fasnacht, T. [Gas Research Inst., Chicago, IL (United States)

1995-06-01T23:59:59.000Z

154

Microwave-based laboratory experiments for internally-heated mantle convection  

SciTech Connect (OSTI)

The thermal evolution of terrestrial planets is mainly controlled by the amount of radioactive heat sources in their mantle, and by the geometry and efficiency of solid state thermo-chemical convection within. So far, these systems have been studied using numerical methods only and cross validation by laboratory analogous experiments has not been conducted yet. To fill this gap we perform the first laboratory experiments of mantle convection driven by microwave-generated internal heating. We use a 30×30×5 cm{sup 3} experimental tank filled with 0.5 % Natrosol in water mixture (viscosity 0.6 Pa.s at 20°C). The fluid is heated from within by a microwave device that delivers a uniform volumetric heating from 10 to 70 kW/m{sup 3}; the upper boundary of the fluid is kept at constant temperature, whereas the lower boundary is adiabatic. The velocity field is determined with particle image velocimetry and the temperature field is measured using thermochromic liquid crystals which enable us to charaterize the geometry of the convective regime as well as its bulk thermal evolution. Numerical simulations, conducted using Stag-3D in 3D cartesian geometry, reproduce the experimental setup (i.e., boundary conditions, box aspect ratio, temperature dependence of physical parameters, internal heating rate). The successful comparison between the experimental and numerical results validates our approach of modelling internal heating using microwaves.

Limare, A.; Di Giuseppe, E.; Vilella, K.; Farnetani, C. G.; Kaminski, E.; Jaupart, C. [Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris-Diderot, CNRS, 1 rue Jussieu, F-75005 Paris (France)] [Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris-Diderot, CNRS, 1 rue Jussieu, F-75005 Paris (France); Surducan, E.; Surducan, V.; Neamtu, C. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)] [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)

2013-11-13T23:59:59.000Z

155

Seismic diagnostics of mixing beyond the convective core in intermediate mass main-sequence stars  

E-Print Network [OSTI]

We study prospects for seismic sounding the layer of a partial mixing above the convective core in main-sequence stars with masses in the 1.2 -- 1.9 solar mass range. There is an initial tendency to an increase of convective core mass in such stars and this leads to ambiguities in modeling. Solar-like oscillations are expected to be excited in such objects. Frequencies of such oscillations provide diagnostics, which are sensitive to the structure of the innermost part of the star and they are known as the small separations. We construct evolutionary models of stars in this mass range assuming various scenarios for element mixing, which includes formation of element abundance jumps, as well as semiconvective and overshooting layers. We find that the three point small separations employing frequencies of radial and dipole modes provide the best probe of the element distribution above the convective core. With expected accuracy of frequency measurement from the space experiments, a discrimination between various scenarios should be possible.

B. L. Popielski; W. A. Dziembowski

2005-05-25T23:59:59.000Z

156

Natural convection heat transfer from a plate in a semicircular enclosure  

SciTech Connect (OSTI)

The present paper is about characterizing the two-dimensional convective transfer across the air-filled region between a flat plate and a semicircular cylindrical enclosure. In the subject geometry, a long thin plate at uniform temperature is contained coaxially and symmetrically in a long semicircular trough closed at the top and having a uniform but different temperature. Heat flows across the air-filled region between the two by both natural convection and gaseous conduction. The problem of characterizing the free convective component of this heat transfer - that is, the component caused by bulk fluid motion - is treated experimentally by using a heat balance technique, with the measurements being repeated at different pressures, in order to cover a wide Rayleigh number range, from Ra {approximately} 10 to Ra {approximately} 10{sup 8}. Nusselt number versus Rayleigh number plots are presented for each of several combinations of plate-to-trough spacing and tilt angle, and the plots are correlated by equations. The problem of characterizing the conductive component is treated by numerically solving the steady diffusion equation in the air-filled region, and the results are correlated as a function of the spacing and the plate thickness.

Moore, G.A.; Hollands, K.G.T. (Univ. of Waterloo, Ontario (Canada))

1992-02-01T23:59:59.000Z

157

atmospheric convective boundary: Topics by E-print Network  

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

convective conditions is found to be primarily due to variations in mixed layer wind speed. Low-level winds thus play the major role in regulating the ability of thermals to...

158

Effects of aerosols on deep convective cumulus clouds  

E-Print Network [OSTI]

This work investigates the effects of anthropogenic aerosols on deep convective clouds and the associated radiative forcing in the Houston area. The Goddard Cumulus Ensemble model (GCE) coupled with a spectral-bin microphysics is employed...

Fan, Jiwen

2009-05-15T23:59:59.000Z

159

Experimental Investigation of Natural Convection in Trombe Wall Systems  

E-Print Network [OSTI]

In this paper, experiments with a passive solar building with Trombe wall in the north cold climate are carried out and discussed, and the natural convection heat transfer process has been investigated. The relativity of the factors affecting indoor...

Chen, B.; Zhao, J.; Chen, C.; Zhuang, Z.

2006-01-01T23:59:59.000Z

160

Rotation of the solar convection zone from helioseismology  

E-Print Network [OSTI]

Helioseismology has provided very detailed inferences about rotation of the solar interior. Within the convection zone the rotation rate roughly shares the latitudinal variation seen in the surface differential rotation. The transition to the nearly uniformly rotating radiative interior takes place in a narrow tachocline, which is likely important to the operation of the solar magnetic cycle.The convection-zone rotation displays zonal flows, regions of slightly more rapid and slow rotation, extending over much of the depth of the convection zone and converging towards the equator as the solar cycle progresses. In addition, there is some evidence for a quasi-periodic variation in rotation, with a period of around 1.3 yr, at the equator near the bottom of the convection zone.

J. Christensen-Dalsgaard

2006-10-31T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Survey and evaluation of techniques to augment convective heat transfer  

E-Print Network [OSTI]

This report presents a survey and evaluation of the numerous techniques which have been shown to augment convective heat transfer. These techniques are: surface promoters, including roughness and treatment; displaced ...

Bergles A. E.

1965-01-01T23:59:59.000Z

162

NATURAL CONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSIS AND RESULTS  

E-Print Network [OSTI]

effect of the adjacent conditioned zones was properly accounted for by the BLASTeffects of this observation on the accuracy of results from the programs, the convection code was used iteratively with BLAST

Gadgil, Ashok; Bauman, Fred; Kammerud, Ronald

2008-01-01T23:59:59.000Z

163

VARIATION OF STELLAR ENVELOPE CONVECTION AND OVERSHOOT WITH METALLICITY  

SciTech Connect (OSTI)

We examine how metallicity affects convection and overshoot in the superadiabatic layer of main sequence stars. We present results from a grid of three-dimensional radiation hydrodynamic simulations with four metallicities (Z = 0.040, 0.020, 0.010, 0.001), and spanning a range in effective temperature (4950 < T{sub eff} < 6230). We show that changing the metallicity alters properties of the convective gas dynamics, and the structure of the superadiabatic layer and atmosphere. Our grid of simulations shows that the amount of superadiabaticity, which tracks the transition from efficient to inefficient convection, is sensitive to changes in metallicity. We find that increasing the metallicity forces the location of the transition region to lower densities and pressures, and results in larger mean and turbulent velocities throughout the superadiabatic region. We also quantify the degree of convective overshoot in the atmosphere, and show that it increases with metallicity as well.

Tanner, Joel D.; Basu, Sarbani; Demarque, Pierre [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)] [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)

2013-04-10T23:59:59.000Z

164

Land-atmosphere interaction and radiative-convective equilibrium  

E-Print Network [OSTI]

I present work on several topics related to land-atmosphere interaction and radiative-convective equilibrium: the first two research chapters invoke ideas related to land-atmosphere interaction to better understand ...

Cronin, Timothy (Timothy Wallace)

2014-01-01T23:59:59.000Z

165

Interaction between surface and atmosphere in a convective boundary layer /  

E-Print Network [OSTI]

heat, and thermal conductivity of the ground and grid sizegrid was stretched uniformly to 0.1 m resolution. The heatheat flux) are friction velocity and convective velocity respectively. The grid

Garai, Anirban

2013-01-01T23:59:59.000Z

166

NATURAL CONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSIS AND RESULTS  

SciTech Connect (OSTI)

Computer programs have been developed to numerically simulate natural convection in two- and three-dimensional room geometries. The programs have been validated using published data from the literature, results from a full-scale experiment performed at the Massachusetts Institute of Technology, and results from a small-scale experiment performed at LBL. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single zone in a direct-gain passive solar building. It is found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface. This study implies that the building heating loads calculated by standard building energy analysis methods may have substantial errors as a result of their use of common assumptions regarding the convection processes which occur in an enclosure.

Gadgil, A.; Bauman, F.; Kammerud, R.

1981-04-01T23:59:59.000Z

167

Possible solar cycle variations in the convection zone  

E-Print Network [OSTI]

Using data from the Global Oscillations Network Group (GONG) that covers the period from 1995 to 1998 we study the change in frequencies of solar oscillations with solar activity. From these frequencies we attempt to determine any possible variation in solar structure with solar activity. We do not find any evidence of a change in the convection zone depth or extent of overshoot below the convection zone during the solar cycle.

Sarbani Basu; H. M. Antia

2000-01-26T23:59:59.000Z

168

Natural convection airflow and heat transport in buildings: experimental results  

SciTech Connect (OSTI)

Observations of natural convection airflow in passive solar buildings are described. Particular results are given for two buildings supplementing other data already published. A number of generalizations based on the monitoring of the 15 buildings are presented. It is concluded that energy can be reasonably well distributed throughout a building by natural convection provided suitable openings are present and that the direction of heat transport is either horizontally across or upward.

Balcomb, J.D.; Jones, G.F.

1985-01-01T23:59:59.000Z

169

Thermal effects of Kohout convection in the Bahamas and Florida  

SciTech Connect (OSTI)

Kohout convection is a low-temperature groundwater thermal convection process in carbonate platform margins. It was first conceived of and postulated to occur in the subsurface of Florida by Francis Kohout in the 1960's. The flow is driven by buoyancy arising from subsurface differences in salinity and in temperature. Cold, dense seawater surrounding a platform at depth migrates inward, displacing warmer pore waters at the same elevation. This inflowing density current is in turn warmed within the platform and is buoyed upward to discharge on the platform shelf or margin resulting in a giant convective half-cell. In isolated platforms, such as the Bahamas, temperature differences alone drive Kohout convection. In Florida, the regional meteoric flow of the Floridan Aquifer mixes by dispersion with the convecting seawater resulting in an enhanced flow rate. Approximate analytical and numerical solutions of the governing differential equations allow the interactions of the flow and temperature fields to be determined. Permeability characteristics and platform margin geometry are the principal controls of the thermal structure and groundwater flow pattern in isolated platforms. In Florida, regional flow strength is also a control. High horizontal permeabilities (100 md to 1 darcy and higher) and tall, steep margins (1 km height, 30/sup 0/ slope) allow Kohout convection to penetrate 30 to 50 km inland causing substantial cooling. It may thus be a control of thermal evolution of the Florida-Bahamas Basin as well as parts of other sedimentary basins.

Simms, M.A.

1985-01-01T23:59:59.000Z

170

The convective structures associated with cloud-to-ground lightning in TOGA COARE Mesoscale Convective Systems  

E-Print Network [OSTI]

suggested that the threshold of about 40 dBZ at the -10 C level for rapid cloud electrification found in New Mexico by Dye et al. (1989) could be valid for tropical convection as well. Orville and Henderson (1986), and Goodman and Christian (1993), have... along with small ice and supercooled liquid water for cloud electrification and lightning to occur. Since most oceanic VPRR drop off rapidly above the freezing level compared to continental VPRR, this would provide evidence that the updraft velocities...

Restivo, Michael Edward

1995-01-01T23:59:59.000Z

171

Dynamic Transitions of Surface Tension Driven Convection  

E-Print Network [OSTI]

We study the well-posedness and dynamic transitions of the surface tension driven convection in a three-dimensional (3D) rectangular box with non-deformable upper surface and with free-slip boundary conditions. It is shown that as the Marangoni number crosses the critical threshold, the system always undergoes a dynamic transition. In particular, two different scenarios are studied. In the first scenario, a single mode losing its stability at the critical parameter gives rise to either a Type-I (continuous) or a Type-II (jump) transition. The type of transitions is dictated by the sign of a computable non-dimensional parameter, and the numerical computation of this parameter suggests that a Type-I transition is favorable. The second scenario deals with the case where the geometry of the domain allows two critical modes which possibly characterize a hexagonal pattern. In this case we show that the transition can only be either a Type-II or a Type-III (mixed) transition depending on another computable non-dimensional parameter. We only encountered Type-III transition in our numerical calculations. The second part of the paper deals with the well-posedness and existence of global attractors for the problem.

Henk Dijkstra; Taylan Sengul; Shouhong Wang

2011-05-05T23:59:59.000Z

172

EVIDENCE FOR CONVECTION IN SUNSPOT PENUMBRAE  

SciTech Connect (OSTI)

We present an analysis of twisting motions in penumbral filaments in sunspots located at heliocentric angles from 30{sup 0} to 48{sup 0} using three time series of blue continuum images obtained by the Broadband Filter Imager (BFI) on board Hinode. The relations of the twisting motions to the filament brightness and the position within the filament and within the penumbra, respectively, are investigated. Only certain portions of the filaments show twisting motions. In a statistical sense, the part of the twisting portion of a filament located closest to the umbra is brightest and possesses the fastest twisting motion, with a mean twisting velocity of 2.1 km s{sup -1}. The middle and outer sections of the twisting portion of the filament (lying increasingly further from the umbra), which are less bright, have mean velocities of 1.7 km s{sup -1} and 1.35 km s{sup -1}, respectively. The observed reduction of brightness and twisting velocity toward the outer section of the filaments may be due to reducing upflow along the filament's long axis. No significant variation of twisting velocity as a function of viewing angles was found. The obtained correlation of brightness and velocity suggests that overturning convection causes the twisting motions observed in penumbral filament and may be the source of the energy needed to maintain the brightness of the filaments.

Bharti, L.; Solanki, S. K.; Hirzberger, J., E-mail: bharti@mps.mpg.d [Max-Planck-Institute fuer sonnensystemforschung, Max-Planck-Str. 2, 37191 Katlenburg-Lindau (Germany)

2010-10-20T23:59:59.000Z

173

Convective variability associated with a mesoscale vortex in a midlatitude squall line system  

E-Print Network [OSTI]

. . . . . . . . . . CASE DESCRIPTION. . STORM MORPHOLOGY Low Levels (surface to 1. 9 km) Mid-to-Low Levels (2. 4 to 3. 9 km). . . . . . . . Mid-to-Upper Levels (4. 4 to 8. 9 km). . . . . . Upper Levels (9. 4 km and above). . . . . . . . . . Vertical Cross... Streamline/isotachanalysisofstorm-relativewinds at1150UTCon 28 May 1985. 1152 UTC dual Doppler analysis of kinematic and reflectivity field at 1. 4 km Mean Sea Level (MSL). . 47 , . 49 20b 1152 UTC dual Doppler analysis of the storm-relative horizontal...

Hristova-Veleva, Svetla M.

1994-01-01T23:59:59.000Z

174

A Large Eddy Simulation of Turbulent Compressible Convection: Differential Rotation in the Solar Convection Zone  

E-Print Network [OSTI]

We present results of two simulations of the convection zone, obtained by solving the full hydrodynamic equations in a section of a spherical shell. The first simulation has cylindrical rotation contours (parallel to the rotation axis) and a strong meridional circulation, which traverses the entire depth. The second simulation has isorotation contours about mid-way between cylinders and cones, and a weak meridional circulation, concentrated in the uppermost part of the shell. We show that the solar differential rotation is directly related to a latitudinal entropy gradient, which pervades into the deep layers of the convection zone. We also offer an explanation of the angular velocity shear found at low latitudes near the top. A non-zero correlation between radial and zonal velocity fluctuations produces a significant Reynolds stress in that region. This constitutes a net transport of angular momentum inwards, which causes a slight modification of the overall structure of the differential rotation near the top. In essence, the {\\it thermodynamics controls the dynamics through the Taylor-Proudman momentum balance}. The Reynolds stresses only become significant in the surface layers, where they generate a weak meridional circulation and an angular velocity `bump'.

Francis J. Robinson; Kwing L. Chan

2000-11-21T23:59:59.000Z

175

Efficient small-scale dynamo in solar convection zone  

E-Print Network [OSTI]

We investigate small-scale dynamo action in the solar convection zone through a series of high resolution MHD simulations in a local Cartesian domain with 1$R_\\odot$ (solar radius) of horizontal extent and a radial extent from 0.715 to 0.96$R_\\odot$. The dependence of the solution on resolution and diffusivity is studied. For a grid spacing of less than 350 km, the root mean square magnetic field strength near the base of the convection zone reaches 95% of the equipartition field strength (i.e. magnetic and kinetic energy are comparable). For these solutions the Lorentz force feedback on the convection velocity is found to be significant. The velocity near the base of the convection zone is reduced to 50% of the hydrodynamic one. In spite of a significant decrease of the convection velocity, the reduction in the enthalpy flux is relatively small, since the magnetic field also suppresses the horizontal mixing of the entropy between up- and downflow regions. This effect increases the amplitude of the entropy pe...

Hotta, H; Yokoyama, T

2015-01-01T23:59:59.000Z

176

Compact range for variable-zone measurements  

DOE Patents [OSTI]

A compact range for testing antennas or radar targets includes a source for directing energy along a feedline toward a parabolic reflector. The reflected wave is a spherical wave with a radius dependent on the distance of the source from the focal point of the reflector.

Burnside, Walter D. (Columbus, OH); Rudduck, Roger C. (Columbus, OH); Yu, Jiunn S. (Albuquerque, NM)

1988-01-01T23:59:59.000Z

177

Revisiting the theoretical DBV (V777 Her) instability strip: the MLT theory of convection  

E-Print Network [OSTI]

We reexamine the theoretical instability domain of pulsating DB white dwarfs (DBV or V777 Her variables). We performed an extensive $g$-mode nonadiabatic pulsation analysis of DB evolutionary models considering a wide range of stellar masses, for which the complete evolutionary stages of their progenitors from the ZAMS, through the thermally pulsing AGB and born-again phases, the domain of the PG1159 stars, the hot phase of DO white dwarfs, and then the DB white dwarf stage have been considered. We explicitly account for the evolution of the chemical abundance distribution due to time-dependent chemical diffusion processes. We examine the impact of the different prescriptions of the MLT theory of convection and the effects of small amounts of H in the almost He-pure atmospheres of DB stars on the precise location of the theoretical blue edge of the DBV instability strip.

A. H. Córsico; L. G. Althaus; M. M. Miller Bertolami; E. Garc\\'\\ia-Berro

2008-10-16T23:59:59.000Z

178

The determination of the natural convection heat transfer coefficients for a heated cylinder in air at sub-atmospheric pressures  

E-Print Network [OSTI]

wire. Electrical power leads were attached to all of the heaters and were led through the interior of the entire assembly. Thermal insulation of the heated portion of the test assembly from the support was provided by using a 1-in. long Micarta tube... VI Presentation of Data 37 References 41 LIST OF FIGURES Figure Page Schematic Diagram of the Test Facility The Test Facility The Natural Convection Vacuum Chamber The Test Cylinder Assembly and the Air Temperature Measuring Probe Schematic...

Sullivan, Lawrence Brozak

2012-06-07T23:59:59.000Z

179

ARM - Midlatitude Continental Convective Clouds (comstock-hvps)  

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

Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

180

The influence of convective heat transfer on flow stability in rotating disk chemical vapor deposition reactors  

SciTech Connect (OSTI)

Flow and heat transfer of NH{sub 3} and He were studied in a rotating disk system with applications to chemical vapor deposition reactors. Flow field and disk heat flux were obtained over a range of operating conditions. Comparisons of disk convective heat transfer were made to infinite rotating disk results to appraise uniformity of transport to the disk. Important operating variables include disk spin rate, disk and enclosure temperatures, flow rate, composition, pressure, and gas mixture temperature at the reactor inlet. These variables were studied over ranges of the spin Reynolds number, Re{omega}; disk mixed convection parameter, MCP{sub w}; and wall mixed convection parameter, MCP{sub w}. Results obtained for NH{sub 3} show that increasing Re{omega} from 314.5 to 3145 increases the uniformity of rotating disk heat flux and results in thinner thermal boundary layers at the disk surface. At Re{omega}=314.5, increasing MCP{sub d} to 15 leads to significant departure from the infinite disk result with nonuniform disk heat fluxes and recirculating flow patterns; flow becomes increasingly complex at larger values of MCP{sub d}. At Re{omega} of 3145, results are closer to the infinite disk for MCP{sub d} up to 15. For large negative (hot walls) and positive (cold walls) values of MCP{sub w}, flow recirculates and there is significant deviation from the infinite disk result; nonuniformities occur at both values of Re{omega}. The influence of MCP{sub w} on flow stability is increased at larger MCP{sub d} and lower Re{omega}. To determine the influence of viscosity and thermal conductivity variation with temperature, calculations were made with He and NH{sub 3}; He transport property variation is low relative to NH{sub 3}. Results show that the flow of NH{sub 3} is less stable than that of He as MCP{sub d} is increased for MCP{sub w}=0 and Re{omega}=314.5. 16 refs., 15 figs., 1 tab.

Winters, W.S.; Evans, G.H. [Sandia National Labs., Livermore, CA (United States); Grief, R. [Univ. of California, Berkeley, CA (United States). Mechanical Engineering Dept.

1997-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Conjugate High Latitude Measurements along the 40 Magnetic Meridian  

E-Print Network [OSTI]

Conjugate High Latitude Measurements along the 40º Magnetic Meridian: Autonomous Adaptive Low the 2014 season marked as red squares. #12;Autonomous Adaptive Low-Power Instrument #12;Conjugate observations of Travelling Convection Vorticies produced by solar wind pressure

Michigan, University of

182

Hydration of the lower stratosphere by ice crystal geysers over land convective systems  

E-Print Network [OSTI]

The possible impact of deep convective overshooting over land has been explored by six simultaneous soundings of water vapour, particles and ozone in the lower stratosphere next to Mesoscale Convective Systems (MCSs) during ...

Khaykin, S.

183

Forced-convection surface-boiling heat transfer and burnout in tubes of small diameters  

E-Print Network [OSTI]

A basic heat-transfer apparatus was designed and constructed for the study of forced-convection boiling in small channels. The various regions of forced-convection surface boiling were studied experimentally and analytically. ...

Bergles A. E.

1962-01-01T23:59:59.000Z

184

Severe convection and lightning in subtropical South America By Kristen L. Rasmussen1  

E-Print Network [OSTI]

1 Severe convection and lightning in subtropical South America of the seasonal, diurnal, and extreme storm-related lightning in South America. · Preference for hail radar and radiometer data show that subtropical South America has the world's deepest convective

Houze Jr., Robert A.

185

Correlated spectral variability in brown dwarfs  

E-Print Network [OSTI]

Models of brown dwarf atmospheres suggest they exhibit complex physical behaviour. Observations have shown that they are indeed dynamic, displaying small photometric variations over timescales of hours. Here I report results of infrared (0.95-1.64 micron) spectrophotometric monitoring of four field L and T dwarfs spanning timescales of 0.1-5.5 hrs, the goal being to learn more about the physical nature of this variability. Spectra are analysed differentially with respect to a simultaneously observed reference source in order to remove Earth-atmospheric variations. The variability amplitude detected is typically 2-10%, depending on the source and wavelength. I analyse the data for correlated variations between spectral indices. This approach is more robust than single band or chisq analyses, because it does not assume an amplitude for the (often uncertain) noise level (although the significance test still assumes a shape for the noise power spectrum). Three of the four targets show significant evidence for correlated variability. Some of this can be associated with specific features including Fe, FeH, VO and KI, and there is good evidence for intrinsic variability in water and possibly also methan. Yet some of this variability covers a broader spectral range which would be consistent with dust opacity variations. The underlying common cause is plausibly localized temperature or composition fluctuations caused by convection. Looking at the high signal-to-noise ratio stacked spectra we see many previously identified spectral features of L and T dwarfs, such as KI, NaI, FeH, water and methane. In particular we may have detected methane absorption at 1.3-1.4 micron in the L5 dwarf SDSS 0539-0059.

C. A. L. Bailer-Jones

2007-11-28T23:59:59.000Z

186

Submitted to Geophysical and Astrophysical Fluid Dynamics Shear and Mixing in Oscillatory Doubly Di usive Convection  

E-Print Network [OSTI]

convection are found in the Earth's oceans, most notably, below the polar ice caps. There melting ice

Paparella, Francesco

187

Classical confinement and outward convection of impurity ions in the MST RFP  

SciTech Connect (OSTI)

Impurity ion dynamics measured with simultaneously high spatial and temporal resolution reveal classical ion transport in the reversed-field pinch. The boron, carbon, oxygen, and aluminum impurity ion density profiles are obtained in the Madison Symmetric Torus [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)] using a fast, active charge-exchange-recombination-spectroscopy diagnostic. Measurements are made during improved-confinement plasmas obtained using inductive control of tearing instability to mitigate stochastic transport. At the onset of the transition to improved confinement, the impurity ion density profile becomes hollow, with a slow decay in the core region concurrent with an increase in the outer region, implying an outward convection of impurities. Impurity transport from Coulomb collisions in the reversed-field pinch is classical for all collisionality regimes, and analysis shows that the observed hollow profile and outward convection can be explained by the classical temperature screening mechanism. The profile agrees well with classical expectations. Experiments performed with impurity pellet injection provide further evidence for classical impurity ion confinement.

Kumar, S. T. A.; Den Hartog, D. J.; Mirnov, V. V.; Eilerman, S.; Nornberg, M.; Reusch, J. A.; Sarff, J. S. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Caspary, K. J.; Chapman, B. E.; Parke, E. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Magee, R. M. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Brower, D. L.; Ding, W. X.; Lin, L. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Craig, D. [Physics Department, Wheaton College, Wheaton, Illinois 60187 (United States); Fiksel, G. [Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Laboratory for Laser Energetics, University of Rochester, Rochester, New York (United States)

2012-05-15T23:59:59.000Z

188

Measured Severe Convective Wind Climatology and Associated Convective Modes of Thunderstorms in the Contiguous United States, 200309  

E-Print Network [OSTI]

of Wisconsin--Madison, Madison, Wisconsin COREY M. MEAD, ANDREW R. DEAN, AND RICHARD L. THOMPSON NOAA

189

weber, evans, moser, and newell Air Traffic Management Decision Support During Convective Weather  

E-Print Network [OSTI]

· weber, evans, moser, and newell Air Traffic Management Decision Support During Convective WeatherTraffic Management Decision Support During Convective Weather Mark E. Weber, James E. Evans, William R. Moser algorithm. #12;· weber, evans, moser, and newell Air Traffic Management Decision Support During Convective

Reuter, Martin

190

The ionospheric signature of transient dayside reconnection and the associated pulsed convection return ow  

E-Print Network [OSTI]

of convection. Key words. Ionosphere (plasma convection) á Magne- tospheric physics (magnetopause, cusp, 1996, and references therein) and the excitation of dayside convection is the focus of the present of magnetosheath plasma into the magneto- sphere, and the ionospheric plasma ¯ow at the footprint of the cusp

Boyer, Edmond

191

Evolution du contenu physique 1. Nouveau bloc couche limite convection nuages (nouvelle physique)  

E-Print Network [OSTI]

Evolution du contenu physique 1. Nouveau bloc couche limite ­ convection ­ nuages (nouvelle physique) ON DISPOSE D'UN NOUVEAU CADRE DE TRAVAIL. ?? - Convection /relief (Jean-Yves Grandpeix, Jingmei Yu, Alain Lahelec) ++ - glace dans la convection (Arnaud Jam, Jean-Yves Grandpeix) ?? - Modèle micro-physique

Madeleine, Jean-Baptiste

192

Observed Synoptic-Scale Variability during the Developing Phase of an ISO over the Indian Ocean during MISMO  

E-Print Network [OSTI]

Observed Synoptic-Scale Variability during the Developing Phase of an ISO over the Indian Ocean A case study of an intraseasonal oscillation (ISO) is investigated in the period leading up to its for a convectively active phase of the ISO. The prominent shallow heating during this period may explain the rather

Johnson, Richard H.

193

Benchmarking Variable Cost Performance in an Industrial Power Plant  

E-Print Network [OSTI]

One of the most perplexing problems for industrial power plants committed to improving competitiveness is measuring variable cost performance over time. Because variable costs like fuel and electricity represent the overwhelming majority of power...

Kane, J. F.; Bailey, W. F.

194

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

SciTech Connect (OSTI)

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.

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

2009-08-20T23:59:59.000Z

195

A numerical study of convection with an ambient wind field  

E-Print Network [OSTI]

. The citations on the following pages follow the style of the Journal of the Atmos heric Sciences. Orville (1968) constructed a convective model based on the same equations as those used by Assi. He concerned himself with the development of cumulus clouds over...

Cottrell, Kit Garfield

1970-01-01T23:59:59.000Z

196

EFFECTS OF SURFACE DEPRESSION AND CONVECTION IN GTA WELDING  

E-Print Network [OSTI]

EFFECTS OF SURFACE DEPRESSION AND CONVECTION IN GTA WELDING M.L. Lin, T.W. Eagar Materials of the weld pool which are changed by these fact ors . It is shown that, at current s in excess of 300 amperes in a different heat distribution on the weld pool surface . ALTHOUGH THE GAS tungsten arc (GTA) welding process

Eagar, Thomas W.

197

Modeling thermal convection in supradetachment basins: example from western Norway  

E-Print Network [OSTI]

Modeling thermal convection in supradetachment basins: example from western Norway A. SOUCHE*, M. DABROWSKI AND T. B. ANDERSEN Physics of Geological Processes (PGP), University of Oslo, Oslo, Norway basins of western Norway are examples of supradetachment basins that formed in the hanging wall

Andersen, Torgeir Bjørge

198

Total lightning observations of severe convection over North Texas  

E-Print Network [OSTI]

Density GSD Gridded Source Density LDAR Lightning Detection and Ranging MCS Mesoscale Convective System MSI Mesocyclone Strength Index MxFED Maximum Flash Extent Density MxFIDT Maximum Flash Initiation Density Total MxGSD Maximum Gridded Source.......................................................................................... 1 1.2 Background ....................................................................................... 4 1.3 Thesis Objectives and Hypothesis...................................................... 19 2. DATA AND METHODOLOGY...

McKinney, Christopher Michael

2009-05-15T23:59:59.000Z

199

Convection venting lensed reflector-type compact fluorescent lamp system  

DOE Patents [OSTI]

Disclosed herein is a fluorescent lamp housing assembly capable of providing convection cooling to the lamp and the ballast. The lens of the present invention includes two distinct portions, a central portion and an apertured portion. The housing assembly further includes apertures so that air mass is able to freely move up through the assembly and out ventilation apertures. 12 figs.

Pelton, B.A.; Siminovitch, M.

1997-07-29T23:59:59.000Z

200

Sparse grid collocation schemes for stochastic natural convection problems  

E-Print Network [OSTI]

stochastic methods and Monte-Carlo based sam- pling methods are two approaches that have been used to analyzeSparse grid collocation schemes for stochastic natural convection problems Baskar on the Smolyak algorithm offers a viable alternate method for solving high-dimensional stochastic partial

Zabaras, Nicholas J.

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Does convective aggregation need to be represented in cumulus parameterizations?  

E-Print Network [OSTI]

Does convective aggregation need to be represented in cumulus parameterizations? Isabelle Tobin,1 in phenomena such as ``hot spots'' or the Madden-Julian Oscillation. These findings support the need climate models lack any such representation. The ability of a cloud system- resolving model to reproduce

202

Drift Natural Convection and Seepage at the Yucca Mountain Repository  

E-Print Network [OSTI]

that the heat and mass transfer of the open in-drift can beheat transfer processes[26, 33], in both the fractured rock and the openheat transfer coefficient, hc eff , as described in Appendix A.2.1. For our case, modeling convection in open

Halecky, Nicholaus Eugene

2010-01-01T23:59:59.000Z

203

NATURAL CONVECTION OF SUBCOOLED LIQUID NITROGEN IN A VERTICAL CAVITY  

E-Print Network [OSTI]

temperature superconductor) power devices, such as HTS transformers, fault current limiters, and terminals power transformer cooled by natural convection of subcooled liquid nitrogen. A liquid nitrogen bath of subcooled liquid nitrogen system for an HTS transformer, operating at around 65 K. This system consists

Chang, Ho-Myung

204

Feedback on vertical velocity. Rotation, convection, self-sustaining process.  

E-Print Network [OSTI]

Feedback on vertical velocity. Rotation, convection, self-sustaining process. Fabian Waleffe the mechanisms involved in the nonlinear feedback from u to v, yielding a self-sustaining process for shear flows feedback from the streak instability into the rolls sufficient to lead to a self-sustaining process

Lebovitz, Norman

205

Numerical analysis of binary fluid convection in extended systems  

E-Print Network [OSTI]

arising in the primary subcritical bifurcation. The dynamics triggered by Eckhaus instability is discussed mixtures. For such mixtures, the onset of convection is via a subcritical Hopf bifurcation that gives rise of S. In the case of the experiment reported in [2] a S = -0.257 water-ethanol mixture is used. A final

Batiste, Oriol

206

Predicting flow reversals in chaotic natural convection using data assimilation  

E-Print Network [OSTI]

. The thermosyphon, a type of natural convection loop or non-mechanical heat pump, can be likened to a toy model of climate. Thermosyphons are used in solar water heaters (Belessiotis and Mathiou- lakis, 2002), cooling) and other industrial applications. In these heat pumps, buoyant forces move fluid through a closed loop

Danforth, Chris

207

OSCILLATORY FLOW FORCED CONVECTION IN MICRO HEAT SPREADERS  

E-Print Network [OSTI]

transfer devices, micro heat pipes, based on capillary pumping of a multiphase ¯uid in microchannels, have-phase forced convection heat transfer and ¯ow characteristics of water in microchannels, both in the laminar) concept for ef cient transport of large, concentrated heat loads is introduced. The MHS is a single

Beskok, Ali

208

Development of Ensemble Neural Network Convection Parameterizations for Climate Models  

SciTech Connect (OSTI)

The novel neural network (NN) approach has been formulated and used for development of a NN ensemble stochastic convection parametrization for climate models. This fast parametrization is built based on data from Cloud Resolving Model (CRM) simulations initialized with and forced by TOGA-COARE data. The SAM (System for Atmospheric Modeling), developed by D. Randall, M. Khairoutdinov, and their collaborators, has been used for CRM simulations. The observational data are also used for validation of model simulations. The SAM-simulated data have been averaged and projected onto the GCM space of atmospheric states to implicitly define a stochastic convection parametrization. This parametrization is emulated using an ensemble of NNs. An ensemble of NNs with different NN parameters has been trained and tested. The inherent uncertainty of the stochastic convection parametrization derived in such a way is estimated. Due to these inherent uncertainties, NN ensemble is used to constitute a stochastic NN convection parametrization. The developed NN convection parametrization have been validated in a diagnostic CAM (CAM-NN) run vs. the control CAM run. Actually, CAM inputs have been used, at every time step of the control/original CAM integration, for parallel calculations of the NN convection parametrization (CAM-NN) to produce its outputs as a diagnostic byproduct. Total precipitation (P) and cloudiness (CLD) time series, diurnal cycles, and P and CLD distributions for the large Tropical Pacific Ocean for the parallel CAM-NN and CAM runs show similarity and consistency with the NCEP reanalysis. The P and CLD distributions for the tropical area for the parallel runs have been analyzed first for the TOGA-COARE boreal winter season (November 1992 through February 1993) and then for the winter seasons of the follow-up parallel decadal simulations. The obtained results are encouraging and practically meaningful. They show the validity of the NN approach. This constitutes an important practical conclusion of the study: the obtained results on NN ensembles as a stochastic physics parametrization show a realistic possibility of development of NN convection parametrization for climate (and NWP) models based on learning cloud physics from CRM/SAM simulated data.

Fox-Rabinovitz, M. S.; Krasnopolsky, V. M.

2012-05-02T23:59:59.000Z

209

Transport of Magnetic Fields in Convective, Accreting Supernova Cores  

E-Print Network [OSTI]

We consider the amplification and transport of a magnetic field in the collapsed core of a massive star, including both the region between the neutrinosphere and the shock, and the central, opaque core. An analytical argument explains why rapid convective overturns persist within a newly formed neutron star for roughly 10 seconds ($> 10^3$ overturns), consistent with recent numerical models. A dynamical balance between turbulent and magnetic stresses within this convective layer corresponds to flux densities in excess of $10^{15}$G. Material accreting onto the core is heated by neutrinos and also becomes strongly convective. We compare the expected magnetic stresses in this convective `gain layer' with those deep inside the neutron core. Buoyant motions of magnetized fluid are greatly aided by the intense neutrino flux. We calculate the transport rate through a medium containing free neutrons protons, and electrons, in the limiting cases of degenerate or non-degenerate nucleons. Fields stronger than $\\sim 10^{13}$ G are able to rise through the outer degenerate layers of the neutron core during the last stages of Kelvin-Helmholtz cooling (up to 10 seconds post-collapse), even though these layers have become stable to convection. We also find the equilibrium shape of a thin magnetic flux rope in the dense hydrostatic atmosphere of the neutron star, along with the critical separation of the footpoints above which the rope undergoes unlimited expansion against gravity. The implications of these results for pulsar magnetism are summarized, and applied to the case of late fallback over the first 1,000-10,000 s of the life of a neutron star

Christopher Thompson; Norman Murray

2001-05-24T23:59:59.000Z

210

A Comparison of Precipitation Forecast Skill between Small Convection-Allowing and Large Convection-Parameterizing Ensembles  

E-Print Network [OSTI]

A Comparison of Precipitation Forecast Skill between Small Convection- Allowing and Large Submitted to Weather and Forecasting in October 2008, Accepted in January 2009 * Corresponding author precipitation forecasts from a 5-member, 4-km grid-spacing (ENS4) and a 15-member, 20-km grid-spacing (ENS20

Droegemeier, Kelvin K.

211

Evaluation of a Modified Scheme for Shallow Convection: Implementation of CuP and Case Studies  

SciTech Connect (OSTI)

A new treatment for shallow clouds has been introduced into the Weather Research and Forecasting (WRF) model. The new scheme, called the cumulus potential (CuP) scheme, replaces the ad-hoc trigger function used in the Kain-Fritsch cumulus parameterization with a trigger function related to the distribution of temperature and humidity in the convective boundary layer via probability density functions (PDFs). An additional modification to the default version of WRF is the computation of a cumulus cloud fraction based on the time scales relevant for shallow cumuli. Results from three case studies over the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) site in north central Oklahoma are presented. These days were selected because of the presence of shallow cumuli over the ARM site. The modified version of WRF does a much better job predicting the cloud fraction and the downwelling shortwave irradiance thancontrol simulations utilizing the default Kain-Fritsch scheme. The modified scheme includes a number of additional free parameters, including the number and size of bins used to define the PDF, the minimum frequency of a bin within the PDF before that bin is considered for shallow clouds to form, and the critical cumulative frequency of bins required to trigger deep convection. A series of tests were undertaken to evaluate the sensitivity of the simulations to these parameters. Overall, the scheme was found to be relatively insensitive to each of the parameters.

Berg, Larry K.; Gustafson, William I.; Kassianov, Evgueni I.; Deng, Liping

2013-01-01T23:59:59.000Z

212

Diamagnetic pumping near the base of a stellar convection zone  

E-Print Network [OSTI]

The property of inhomogeneous turbulence in conducting fluids to expel large-scale magnetic fields in the direction of decreasing turbulence intensity is shown as important for the magnetic field dynamics near the base of a stellar convection zone. The downward diamagnetic pumping confines a fossil internal magnetic field in the radiative core so that the field geometry is appropriate for formation of the solar tachocline. For the stars of solar age, the diamagnetic confinement is efficient only if the ratio of turbulent magnetic diffusivity of the convection zone to the (microscopic or turbulent) diffusivity of the radiative interiour is larger than 10^5. Confinement in younger stars require still larger diffusivity ratio. The observation of persistent magnetic structures on young solar-type stars can thus provide evidences for the nonexistence of tachoclines in stellar interiors and on the level of turbulence in radiative cores.

L. L. Kitchatinov; G. Rüdiger

2008-02-18T23:59:59.000Z

213

Dissipation Efficiency in Turbulent Convective Zones in Low Mass Stars  

E-Print Network [OSTI]

We extend the analysis of Penev et al. (2007) to calculate effective viscosities for the surface convective zones of three main sequence stars of 0.775Msun, 0.85Msun and the present day Sun. In addition we also pay careful attention to all normalization factors and assumptions in order to derive actual numerical prescriptions for the effective viscosity as a function of the period and direction of the external shear. Our results are applicable for periods that are too long to correspond to eddies that fall within the inertial subrange of Kolmogorov scaling, but no larger than the convective turnover time, when the assumptions of the calculation break down. We find linear scaling of effective viscosity with period and magnitudes at least three times larger than the Zahn (1966, 1989) prescription.

Kaloyan Penev; Dimitar Sasselov; Frank Robinson; Pierre Demarque

2009-09-26T23:59:59.000Z

214

The Critical Rayleigh Number in Horizontal Convection for $\\Pran=1$  

E-Print Network [OSTI]

We report the numerical simulations of the horizontal convection within a rectangle cavity tank at high Rayleigh numbers. The physical solution of horizontal convection depends the space resolution of the meshes. The mesh number $N$ is proportion to $Ra^{1/3}$. The unstable numerical solutions are obtained as $Npower law also implies that the space resolution is dominated by the viscosity and heat diffusion. It implies that the special resolution is dominated by viscosity and thermal diffusivity but the length of the tank. Moreover, there is a Hopf bifurcation from steady solutions to unsteady solutions and the critical Rayleigh number $Ra_c$ is obtained as $5.53\\times 10^8

Sun, L; Sun, De-Jun; Sun, Liang

2007-01-01T23:59:59.000Z

215

COMPARING THE EFFECT OF RADIATIVE TRANSFER SCHEMES ON CONVECTION SIMULATIONS  

SciTech Connect (OSTI)

We examine the effect of different radiative transfer schemes on the properties of three-dimensional (3D) simulations of near-surface stellar convection in the superadiabatic layer, where energy transport transitions from fully convective to fully radiative. We employ two radiative transfer schemes that fundamentally differ in the way they cover the 3D domain. The first solver approximates domain coverage with moments, while the second solver samples the 3D domain with ray integrations. By comparing simulations that differ only in their respective radiative transfer methods, we are able to isolate the effect that radiative efficiency has on the structure of the superadiabatic layer. We find the simulations to be in good general agreement, but they show distinct differences in the thermal structure in the superadiabatic layer and atmosphere.

Tanner, Joel D.; Basu, Sarbani; Demarque, Pierre [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)

2012-11-10T23:59:59.000Z

216

Influence of geometry on natural convection in buildings  

SciTech Connect (OSTI)

Strong free convection airflows occur within passive solar buildings resulting from elevated temperatures of surfaces irradiated by solar energy compared with the cooler surfaces not receiving radiation. The geometry of a building has a large influence on the directions and magnitudes of natural airflows, and thus heat transfer between zones. This investigation has utilized a variety of reduced-scale building configurations to study the effects of geometry on natural convection heat transfer. Similarity between the reduced-scale model and a full-scale passive solar building is achieved by having similar geometries and by replacing air with Freon-12 gas as the model's working fluid. Filling the model with Freon-12 gas results in similarity in Prandtl numbers and Rayleigh numbers based on temperature differences in the range from 10/sup 9/ to 10/sup 11/. Results from four geometries are described with an emphasis placed on the effects of heat loss on zone temperature stratification shifts.

White, M.D.; Winn, C.B.; Jones, G.F.; Balcomb, J.D.

1985-01-01T23:59:59.000Z

217

Evolution of moisture convergence in a mesoscale convective complex  

E-Print Network [OSTI]

Committee: Dr. Keuneth C. Brundidge Two separate Mesoscale Convective Complexes (MCCs) were investigated to determine if a characteristic surface moisture convergence (MC) signature existed on the mesoscale during their lifecycle. The first storm (Case 1... convergence, a bandpass filtering technique was utilized. It was found that MC could identify the general area of initial thunderstorm activity 2 h prior to its development for both cases. During the initial development stage of Case 1, advection...

Bercherer, John Phillip

1990-01-01T23:59:59.000Z

218

THE DOMINANCE OF NEUTRINO-DRIVEN CONVECTION IN CORE-COLLAPSE SUPERNOVAE  

SciTech Connect (OSTI)

Multi-dimensional instabilities have become an important ingredient in core-collapse supernova (CCSN) theory. Therefore, it is necessary to understand the driving mechanism of the dominant instability. We compare our parameterized three-dimensional CCSN simulations with other buoyancy-driven simulations and propose scaling relations for neutrino-driven convection. Through these comparisons, we infer that buoyancy-driven convection dominates post-shock turbulence in our simulations. In support of this inference, we present four major results. First, the convective fluxes and kinetic energies in the neutrino-heated region are consistent with expectations of buoyancy-driven convection. Second, the convective flux is positive where buoyancy actively drives convection, and the radial and tangential components of the kinetic energy are in rough equipartition (i.e., K{sub r} {approx} K{sub {theta}} + K{sub {phi}}). Both results are natural consequences of buoyancy-driven convection, and are commonly observed in simulations of convection. Third, buoyant driving is balanced by turbulent dissipation. Fourth, the convective luminosity and turbulent dissipation scale with the driving neutrino power. In all, these four results suggest that in neutrino-driven explosions, the multi-dimensional motions are consistent with neutrino-driven convection.

Murphy, Jeremiah W.; Dolence, Joshua C.; Burrows, Adam, E-mail: jmurphy@astro.princeton.edu, E-mail: jdolence@astro.princeton.edu, E-mail: burrows@astro.princeton.edu [Princeton University, Princeton, NJ (United States)

2013-07-01T23:59:59.000Z

219

Variable frequency microwave heating apparatus  

DOE Patents [OSTI]

A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity (34) for testing or other selected applications. The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a high-power microwave oscillator (14). A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20). A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34). A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN); Johnson, Arvid C. (Lake in the Hills, IL); Thigpen, Larry T. (Angier, NC)

1999-01-01T23:59:59.000Z

220

Ring diagram analysis of velocity fields within the solar convection zone  

E-Print Network [OSTI]

Ring diagram analysis of solar oscillation power spectra obtained from MDI data is performed to study the velocity fields within the solar convection zone. The three dimensional power spectra are fitted to a model with a Lorentzian profile in frequency and includes the advection of the wave front by horizontal flows to obtain the two horizontal components of flows as a function of the horizontal wave number and radial order of the oscillation modes. This information is then inverted using the OLA and RLS techniques to infer the variation in flow velocity with depth. The resulting velocity fields yield the mean rotation velocity at different latitudes which agrees reasonably with helioseismic estimates. The zonal flow inferred in the outermost layers also appears to be in agreement with other measurements. A meridional flow from equator polewards is found to have an amplitude of about 25 m/s near the surface and the amplitude appears to increase with depth.

Sarbani Basu; H. M. Antia; S. C. Tripathy

1998-06-23T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

SOUND-SPEED INVERSION OF THE SUN USING A NONLOCAL STATISTICAL CONVECTION THEORY  

SciTech Connect (OSTI)

Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of the solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the local mixing-length theory adopted in the standard solar model. Using a self-consistent nonlocal convection theory, we construct an envelope model of the Sun for sound-speed inversion. Our solar model has a very smooth transition from the convective envelope to the radiative interior, and the convective energy flux changes sign crossing the boundaries of the convection zone. It shows evident improvement over the standard solar model, with a significant reduction in the discrepancy in sound speed between the Sun and local convection models.

Zhang Chunguang; Deng Licai [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Xiong Darun [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Christensen-Dalsgaard, Jorgen, E-mail: cgzhang@nao.cas.cn [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark)

2012-11-01T23:59:59.000Z

222

Understanding Biomass Feedstock Variability  

SciTech Connect (OSTI)

If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per ton supply cost of biomass, these systems may very well develop with ultimate unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that due to inherent species variabilities, production conditions, and differing harvest, collection, and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture, and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.

Kevin L. Kenney; William A. Smith; Garold L. Gresham; Tyler L. Westover

2013-01-01T23:59:59.000Z

223

Understanding Biomass Feedstock Variability  

SciTech Connect (OSTI)

If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per-ton supply cost of biomass, these systems may very well develop with ultimate unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that, due to inherent species variabilities, production conditions and differing harvest, collection and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.

Kevin L. Kenney; Garold L. Gresham; William A. Smith; Tyler L. Westover

2013-01-01T23:59:59.000Z

224

Velocity and temperature distribution of air in the boundary layer of a vertical plate for free-convective heat transfer  

E-Print Network [OSTI]

against the nozzle and clamped to. a stand in such a way that its vertical position could be, set. as desired. Hot-Wire Anemometer A Plow Corporation Model HWB2 hot wire anemometer was used in connection with a single, filament, probe to measure...VELOCITY AND TEMPERATURE DISTRIBUTION OF AIR IN THE BOUNDARY LAYER OF A VERTICAL PLATE FOR FREE-CONVECTIVE HEAT TRANSFER A Thesis By JEAN MAXIME JOSE JULLIENNE Submitted to . the . Graduate School of the Agricultural. and Mechanical. College...

Jullienne, Jean Maxime Jose

2012-06-07T23:59:59.000Z

225

Damping of Type I X-ray Burst Oscillations by Convection  

E-Print Network [OSTI]

I construct a simple model of the convective burning layer during a type I X-ray burst to investigate the effects convection has on the stability of the layer to nonradial oscillations. A linear perturbation analysis demonstrates that the region is stable to nonradial oscillations when energy transport is convection-dominated, but it is unstable when energy transport is radiation-dominated. Thus, efficient convection always dampens oscillations. These results may explain the nondetection of oscillations during the peak of some X-ray bursts.

Randall L. Cooper

2008-03-26T23:59:59.000Z

226

E-Print Network 3.0 - axially focusing convection Sample Search...  

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

wall. The results show that the laminar forced convective heat transfer inside the tube never Source: Zhang, Yuwen - Department of Mechanical and Aerospace Engineering,...

227

A numerical study of mesoscale convection in a rotating tropical atmosphere  

E-Print Network [OSTI]

similar to the profile of a tropical disturbance. The meso-p forcing of convection consisted of' seven temperature perturbations con- fined below 2. 4 km at intervals of 8 km out to 60 km. The meso-9 forcing of convection comprised of a cosine thermal... perturbation field out to 75 km. Two different classes of simulations were performed. The first part explored how background vorticity affects convection generated by meso-7 and meso-9 forcing. The second part investigated how meso-9 forcing of convection...

Fitzpatrick, Patrick James

1992-01-01T23:59:59.000Z

228

SRS reactor control rod cooling without normal forced convection cooling  

SciTech Connect (OSTI)

This paper describes an analytical study of the coolability of the control rods in the Savannah River site (SRS) K production reactor under conditions of loss of normal forced convection cooling. The study was performed as part of the overall safety analysis of the reactor supporting its restart. The analysis addresses the buoyancy-driven boiling flow over the control rods that occurs when forced cooling is lost. The objective of the study was to demonstrate that the control rods will remain cooled (i.e., no melting) at powers representative of those anticipated for restart of the reactor.

Smith, D.C. (SAIC, Albuquerque, NM (United States)); Easterling, T.C. (Westinghouse Savannah River Co., Aiken, SC (United States))

1993-01-01T23:59:59.000Z

229

Gradients of meteorological parameters in convective and nonconvective areas  

E-Print Network [OSTI]

. SYNOPTIC CONDITIONS 4. STRATIFICATION OF DATA 5. COMPUTATIONAL PROCEDURES 21 25 a. Gridding of rawinsonde data 25 b. Gradients 26 5'' lp t* 27 RESULTS 29 a. Gradients 29 1) Convective areas 29 2) Nonconvective areas 31 3) Combined areas 33 vi... air turbulence. By using airplane data from over the western United States, Scoggins (1975) has shown that CAT at 300 mb occurred 71% of the time when the magnitude of the vector horizontal wind shear -5 -1 exceeded 4. 5 x 10 sec . The horizontal...

McCown, Milton Samuel

1976-01-01T23:59:59.000Z

230

Generation of large-scale winds in horizontally anisotropic convection  

E-Print Network [OSTI]

We simulate three-dimensional, horizontally periodic Rayleigh-B\\'enard convection between free-slip horizontal plates, rotating about a horizontal axis. When both the temperature difference between the plates and the rotation rate are sufficiently large, a strong horizontal wind is generated that is perpendicular to both the rotation vector and the gravity vector. The wind is turbulent, large-scale, and vertically sheared. Horizontal anisotropy, engendered here by rotation, appears necessary for such wind generation. Most of the kinetic energy of the flow resides in the wind, and the vertical turbulent heat flux is much lower on average than when there is no wind.

von Hardenberg, J; Provenzale, A; Spiegel, E A

2015-01-01T23:59:59.000Z

231

Overshooting Convection from High-resolution NEXRAD Observations  

E-Print Network [OSTI]

employs the difference between 6-7 µm water vapor absorption and ?11 µm infrared window channel brightness temper- ature for overshooting convection detection (e.g., Fritz and Laszlo, 1993; Ackerman, 2 1996; Schmetz et al., 1997; Setvak et al., 2007... and in Radiative Forcing, pp. 129–234, Cambridge University Press, Cambridge, UK. Fritz, S., and I. Laszlo (1993), Detection of water vapor in the stratosphere over very high clouds in the tropics, J. Geophys. Res., 98 (D12), 22,959–22,967. 32 Fromm, M. D., and R...

Solomon, David

2014-01-09T23:59:59.000Z

232

Natural convection in high heat flux tanks at the Hanford Waste Site / [by] Mark van der Helm and Mujid S. Kazimi  

E-Print Network [OSTI]

A study was carried out on the potential for natural convection and the effect of natural convection in a High Heat Flux Tank, Tank 241-C-106, at the Hanford Reservation. To determine the existence of natural convection, ...

Van der Helm, Mark Johan, 1972-

1996-01-01T23:59:59.000Z

233

Convection induced by radiative cooling of a layer of participating medium  

SciTech Connect (OSTI)

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.

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

234

Diurnal Cycle of Convection at the ARM SGP Site: Role of Large-Scale Forcing, Surface Fluxes, and Convective Inhibition  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed Newcatalyst phasesDataTranslocationDiurnal Cycle of Convection at the ARM SGP Site:

235

Variable Frequency Pump Drives  

E-Print Network [OSTI]

-frequency electric motor drive. What is happenin9 with variable frequency driven pun,ps is a classical illustration that evolution in technical products takes place not only because of changes in the processes served by these products, or because of innovations...-pole 3550 rpm squirrel caqe induction motor became available in the early 1930s that high pressure pumps operating at that speed could be buil t. And now, in the 1980s, the development of the solid-state, variable frequency electric motor drive...

Karassik, I. J.; Petraccaro, L. L.; McGuire, J. T.

236

Conceptual Design of Forced Convection Molten Salt Heat Transfer Testing Loop  

SciTech Connect (OSTI)

This report develops a proposal to design and construct a forced convection test loop. A detailed test plan will then be conducted to obtain data on heat transfer, thermodynamic, and corrosion characteristics of the molten salts and fluid-solid interaction. In particular, this report outlines an experimental research and development test plan. The most important initial requirement for heat transfer test of molten salt systems is the establishment of reference coolant materials to use in the experiments. An earlier report produced within the same project highlighted how thermophysical properties of the materials that directly impact the heat transfer behavior are strongly correlated to the composition and impurities concentration of the melt. It is therefore essential to establish laboratory techniques that can measure the melt composition, and to develop purification methods that would allow the production of large quantities of coolant with the desired purity. A companion report describes the options available to reach such objectives. In particular, that report outlines an experimental research and development test plan that would include following steps: •Molten Salts: The candidate molten salts for investigation will be selected. •Materials of Construction: Materials of construction for the test loop, heat exchangers, and fluid-solid corrosion tests in the test loop will also be selected. •Scaling Analysis: Scaling analysis to design the test loop will be performed. •Test Plan: A comprehensive test plan to include all the tests that are being planned in the short and long term time frame will be developed. •Design the Test Loop: The forced convection test loop will be designed including extensive mechanical design, instrument selection, data acquisition system, safety requirements, and related precautionary measures. •Fabricate the Test Loop. •Perform the Tests. •Uncertainty Analysis: As a part of the data collection, uncertainty analysis will be performed to develop probability of confidence in what is measured in the test loop. Overall, the testing loop will allow development of needed heat transfer related thermophysical parameters for all the salts, validate existing correlations, validate measuring instruments under harsh environment, and have extensive corrosion testing of materials of construction.

Manohar S. Sohal; Piyush Sabharwall; Pattrick Calderoni; Alan K. Wertsching; S. Brandon Grover

2010-09-01T23:59:59.000Z

237

Kinetics of the clay roofing tile convection drying  

SciTech Connect (OSTI)

Kinetics of the convection drying process of flat tile has been investigated experimentally in an industrial tunnel dryer. Several velocities of wet tile movement through the dryer were tested to obtain maximum allowable drying rate curve. As there are various models to describe the kinetics of convection drying, finding a model that would fairly well approximate the kinetics of the whole drying process was part of the research. Especially the polynomial and exponential models were tested. It was found that exponential model of the type: B(t) = (a[minus]B[sub e])[center dot]EXP([minus]bt[sup 2])+B[sub e], ([minus]dB(t)/dt) = 2bt(B(t)[minus]B[sub e]) significantly correlates the kinetics of the whole tile drying process. Applying the maximum allowable drying rate curve obtained for flat tile in the first period of drying, a grapho-analytic model for the optimal conducting of the process has been developed.

Thomas, S. (Univ. of Osijek (Croatia). Faculty of Food Technology); Skansi, D. (Univ. of Zagreb (Croatia). Faculty of Chemical Engineering and Technology); Sokele, M. (Croatian Post and Telecommunications, Zagreb (Croatia). Telecommunications Center)

1993-01-01T23:59:59.000Z

238

A Multiscale Dynamo Model Driven by Quasi-geostrophic Convection  

E-Print Network [OSTI]

A convection-driven multiscale dynamo model is developed for the plane layer geometry in the limit of low Rossby number. The small-scale fluctuating dynamics are described by a magnetically-modified quasi-geostrophic equation set, and the large-scale mean dynamics are governed by a diagnostic thermal wind balance. The model utilizes three timescales that respectively characterize the convective timescale, the large-scale magnetic diffusion timescale, and the large-scale thermal diffusion timescale. Distinct equations are derived for the cases of order one and low magnetic Prandtl number. It is shown that the low magnetic Prandtl number model is characterized by a magnetic to kinetic energy ratio that is asymptotically large, with ohmic dissipation dominating viscous dissipation on the large-scales. For the order one magnetic Prandtl number model the magnetic and kinetic energies are equipartitioned and both ohmic and viscous dissipation are weak on the large-scales; large-scale ohmic dissipation occurs in thi...

Calkins, Michael A; Tobias, Steven M; Aurnou, Jonathan M

2015-01-01T23:59:59.000Z

239

Particle filter based on thermophoretic deposition from natural convection flow  

SciTech Connect (OSTI)

We present an analysis of particle migration in a natural convection flow between parallel plates and within the annulus of concentric tubes. The flow channel is vertically oriented with one surface maintained at a higher temperature than the other. Particle migration is dominated by advection in the vertical direction and thermophoresis in the horizontal direction. From scale analysis it is demonstrated that particles are completely removed from air flowing through the channel if its length exceeds L[sub c] = (b[sup 4]g/24K[nu][sup 2]), where b is the width of the channel, g is the acceleration of gravity, K is a thermophoretic coefficient of order 0.5, and [nu] is the kinematic viscosity of air. Precise predictions of particle removal efficiency as a function of system parameters are obtained by numerical solution of the governing equations. Based on the model results, it appears feasible to develop a practical filter for removing smoke particles from a smoldering cigarette in an ashtray by using natural convection in combination with thermophoresis. 22 refs., 8 figs., 1 tab.

Sasse, A.G.B.M.; Nazaroff, W.W. (Univ. of California, Berkeley, CA (United States)); Gadgil, A.J. (Lawrence Berkeley Lab., CA (United States))

1994-04-01T23:59:59.000Z

240

Simulated Convective Invigoration Processes at Trade Wind Cumulus Cold Pool ZHUJUN LI AND PAQUITA ZUIDEMA  

E-Print Network [OSTI]

convection and cold pools using a nested­Weather Research and Fore- casting Model simulation of 19 January ratio drops in simulated cold pools fall within the envelope of observed cases, and the wind enhancement pools invigorating convection at their downwind boundary and suppressing thermals in- side the stable

Zuidema, Paquita

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation  

SciTech Connect (OSTI)

By applying a cloud tracking algorithm to tropical convective systems simulated by a regional high resolution model, the study documents environmental conditions before and after convective systems are initiated over ocean and land by following them during their lifetime. The comparative roles of various environmental fields in affecting the lifetime of convection are also quantified. The statistics of lifetime, maximum area, propagation speed and direction of the simulated deep convection agrees well with geostationary satellite observations. Over ocean, convective systems enhance surface fluxes through the associated wind gusts as well as cooling and drying of the boundary layer. A significant relationship is found between the mean surface fluxes during their lifetime and the longevity of the systems which in turn is related to the initial intensity of the moist updraft and to a lesser extent upper level shear. Over land, on the other hand, convective activity suppresses surface fluxes through cloud cover and the lifetime of convection is related to the upper level shear during their lifetime and strength of the heat fluxes several hours before the initiation of convection. For systems of equal lifetime, those over land are significantly more intense than those over ocean especially during early stages of their lifetime.

Hagos, Samson M.; Feng, Zhe; McFarlane, Sally A.; Leung, Lai-Yung R.

2013-08-01T23:59:59.000Z

242

Improving Convection Parameterization Using ARM Observations and NCAR Community Atmosphere Model  

SciTech Connect (OSTI)

Highlight of Accomplishments: We made significant contribution to the ASR program in this funding cycle by better representing convective processes in GCMs based on knowledge gained from analysis of ARM/ASR observations. In addition, our work led to a much improved understanding of the interaction among aerosol, convection, clouds and climate in GCMs.

Zhang, Guang J [Scripps Institution of Oceanography

2013-07-29T23:59:59.000Z

243

Convective heat transfer as a function of wavelength: Implications for the cooling of the Earth  

E-Print Network [OSTI]

Convective heat transfer as a function of wavelength: Implications for the cooling of the Earth C, in particular, on its variation with the wavelength of convection. The heat transfer strongly depends in Earth's mantle can significantly reduce the efficiency of heat transfer. The likely variations

244

HEAT TRANSFERS IN A DOUBLE SKIN ROOF VENTILATED BY NATURAL CONVECTION IN SUMMER TIME  

E-Print Network [OSTI]

1 HEAT TRANSFERS IN A DOUBLE SKIN ROOF VENTILATED BY NATURAL CONVECTION IN SUMMER TIME P. H or in tropical and arid countries. In this work, radiation, convection and conduction heat transfers-dimensional numerical simulation of the heat transfers through the double skin reveals the most important parameters

Boyer, Edmond

245

Modelling the convective flow in solar thermal receivers K.C. Yeh; G. Hughes & K. Lovegrove  

E-Print Network [OSTI]

value energy conversions such as heat engine cycles or chemical process to be carried outModelling the convective flow in solar thermal receivers K.C. Yeh; G. Hughes & K. Lovegrove, Canberra AUSTRALIA E-mail: u3370739@anu.edu.au The natural convective flow inside a concentrating solar

246

Observations of prolific transient luminous event production above a mesoscale convective system in Argentina during  

E-Print Network [OSTI]

in Argentina during the Sprite2006 Campaign in Brazil F. T. São Sabbas,1 M. J. Taylor,2 P.D. Pautet,2 M. Bailey convective system (MCS) over Argentina, as part of the third sprite campaign in Brazil. GOES infrared (IR a mesoscale convective system in Argentina during the Sprite2006 Campaign in Brazil, J. Geophys. Res., 115, A

Thomas, Jeremy N.

247

Numerical study of natural convection in a vertical porous annulus with discrete heating  

E-Print Network [OSTI]

­10]. Among the finite enclosures, free convective heat transfer in a differentially heated vertical porous in a vertical annular enclosure for a wide range of radius and aspect ratios, and also used an approximateNumerical study of natural convection in a vertical porous annulus with discrete heating M. Sankar

Lopez, John M.

248

Numerical Investigation of Natural Convection Loss in Cavity-Type Solar Receivers  

E-Print Network [OSTI]

Work There have been several previous investigations of natural convection heat loss from open the convective heat loss, i.e., (i) the ability to transfer mass and energy across the aperture and (ii to investigate three cases of geometrically different receivers. The calculated heat loss results shows

249

Dielectrophoretic Rayleigh-Benard convection under microgravity conditions H. N. Yoshikawa,  

E-Print Network [OSTI]

conditions. A thermo-electric coupling resulting from the thermal variation of the electric permittivity of the fluid produces the dielectrophoretic (DEP) body force, which can be regarded as thermal buoyancy due of the GL equation are comparable with those for the RB convection. The heat transfer in the DEP convection

Paris-Sud XI, Université de

250

The impact of methane thermodynamics on seasonal convection and circulation in a model Titan atmosphere  

E-Print Network [OSTI]

The impact of methane thermodynamics on seasonal convection and circulation in a model Titan mechanisms controlling the distribution of methane convection and large-scale circulation in a simplified, axisymmetric model atmosphere of Titan forced by gray radiation and moist (methane) con- vection. The large

Caballero, Rodrigo

251

Pattern formation in binary mixture convection in cylindrical three-dimensional cells  

E-Print Network [OSTI]

present numerical results of pattern selection near the onset of convection for a water-ethanol mixture of the cell is = 11. The onset of convection occurs via a subcritical Hopf bifurcation. Slightly above ratio mixtures, S subcritical and gives rise

Batiste, Oriol

252

THE MAGNETIC CONNECTION BETWEEN THE CONVECTION ZONE AND CORONA IN THE QUIET SUN  

E-Print Network [OSTI]

THE MAGNETIC CONNECTION BETWEEN THE CONVECTION ZONE AND CORONA IN THE QUIET SUN W. P. Abbett Space connection between the convectively unstable layers below the visible surface of the Sun and the overlying application of this numerical model, we present a series of simulations of the quiet Sun in a domain

Abbett, Bill

253

Impact of Convective Organization on the Response of Tropical Precipitation Extremes to Warming  

E-Print Network [OSTI]

Impact of Convective Organization on the Response of Tropical Precipitation Extremes to Warming extremes to warming in organized convection is ex- amined using a cloud-resolving model. Vertical shear, the fractional increase of precipitation extremes is similar to that of surface water vapor, which

Paris-Sud XI, Université de

254

3D Simulation of Convection and Spectral Line Formation in A-type Stars  

E-Print Network [OSTI]

We present first realistic numerical simulations of 3D radiative convection in the surface layers of main sequence A-type stars with Teff = 8000 K and 8500 K, log g = 4.4 and 4.0, recently performed with the CO5BOLD radiation hydrodynamics code. The resulting models are used to investigate the structure of the H+HeI and the HeII convection zones in comparison with the predictions of local and non-local convection theories, and to determine the amount of "overshoot" into the stable layers below the HeII convection zone. The simulations also predict how the topology of the photospheric granulation pattern changes from solar to A-type star convection. The influence of the photospheric temperature fluctuations and velocity fields on the shape of spectral lines is demonstrated by computing synthetic line profiles and line bisectors for some representative examples, allowing us to confront the 3D model results with observations.

M. Steffen; B. Freytag; H. -G. Ludwig

2005-09-15T23:59:59.000Z

255

3. Hydrogeomorphic Variability and River Restoration  

E-Print Network [OSTI]

. It is difficult to design effective stream and channel restoration measures, or evaluate project performance expansion of efforts in and expenditures for stream restoration. Increasingly, resto- ration efforts focus39 3. Hydrogeomorphic Variability and River Restoration D. R. MONTGOMERY1 AND S. M. BOLTON2

Montgomery, David R.

256

NUMERICAL DETERMINATION AND TREATMENT OF CONVECTIVE HEAT TRANSFER COEFFICIENT IN THE COUPLED BUILDING ENERGY AND CFD SIMULATION  

E-Print Network [OSTI]

for the correct prediction of the convective heat. A finer grid resolution in CFD does not always lead to a more conservation equations of flow on these grid cells. As shown in Figure 1(a), CFD calculates convective heat1 NUMERICAL DETERMINATION AND TREATMENT OF CONVECTIVE HEAT TRANSFER COEFFICIENT IN THE COUPLED

Chen, Qingyan "Yan"

257

Magnetospheric Convection The large-scale flow of rarefied plasma in the Earth's magnetosphere "is quite analogous to  

E-Print Network [OSTI]

quite analogous to thermal convection" (Gold, 1959); therefore, the term "convection" is commonly used of geomagnetic field lines in the crossed E and B fields. By analogy with the thermal convection in a non in the magnetosheath: a region between the bow shock and the magnetopause. A similar flow pattern is formed

Michigan, University of

258

Orogenic Convection in Subtropical South America as Seen by the TRMM Satellite KRISTEN L. RASMUSSEN AND ROBERT A. HOUZE JR.  

E-Print Network [OSTI]

Orogenic Convection in Subtropical South America as Seen by the TRMM Satellite KRISTEN L. RASMUSSEN storms in southeastern South America are divided into three categories: storms with deep convective cores, the intense storms with wide convective cores over southeastern South America are unlike their Himalayan

Houze Jr., Robert A.

259

EXPERIMENTAL INVESTIGATION OF NATURAL CONVECTION HEAT TRANSFER OF IONIC LIQUID IN A RECTANGULAR ENCLOSURE HEATED FROM BELOW  

SciTech Connect (OSTI)

This paper presents an experimental study of natural convection heat transfer for an Ionic Liquid. The experiments were performed for 1-butyl-2, 3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, ([C{sub 4}mmim][NTf{sub 2}]) at a Raleigh number range of 1.26 x 10{sup 7} to 8.3 x 10{sup 7}. In addition to determining the convective heat transfer coefficients, this study also included experimental determination of thermophysical properties of [C{sub 4}mmim][NTf{sub 2}] such as, density, viscosity, heat capacity, and thermal conductivity. The results show that the density of [C{sub 4}mmim][NTf{sub 2}] varies from 1.437-1.396 g/cm{sup 3} within the temperature range of 10-50 C, the thermal conductivity varies from 0.105-0.116 W/m.K between a temperature of 10 to 60 C, the heat capacity varies from 1.015 J/g.K - 1.760 J/g.K within temperature range of 25-340 C and the viscosity varies from 18cp-243cp within temperature range 10-75 C. The results for density, thermal conductivity, heat capacity, and viscosity were in close agreement with the values in the literature. Measured dimensionless Nusselt number was observed to be higher for the ionic liquid than that of DI water. This is expected as Nusselt number is the ratio of heat transfer by convection to conduction and the ionic liquid has lower thermal conductivity (approximately 18%) than DI water.

Fox, E.; Visser, A.; Bridges, N.

2011-07-18T23:59:59.000Z

260

Variable frequency microwave furnace system  

DOE Patents [OSTI]

A variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34) for testing or other selected applications. The variable frequency microwave furnace system (10) includes a microwave signal generator (12) or microwave voltage-controlled oscillator (14) for generating a low-power microwave signal for input to the microwave furnace. A first amplifier (18) may be provided to amplify the magnitude of the signal output from the microwave signal generator (12) or the microwave voltage-controlled oscillator (14). A second amplifier (20) is provided for processing the signal output by the first amplifier (18). The second amplifier (20) outputs the microwave signal input to the furnace cavity (34). In the preferred embodiment, the second amplifier (20) is a traveling-wave tube (TWT). A power supply (22) is provided for operation of the second amplifier (20). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN)

1994-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Variable frequency microwave furnace system  

DOE Patents [OSTI]

A variable frequency microwave furnace system designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity for testing or other selected applications. The variable frequency microwave furnace system includes a microwave signal generator or microwave voltage-controlled oscillator for generating a low-power microwave signal for input to the microwave furnace. A first amplifier may be provided to amplify the magnitude of the signal output from the microwave signal generator or the microwave voltage-controlled oscillator. A second amplifier is provided for processing the signal output by the first amplifier. The second amplifier outputs the microwave signal input to the furnace cavity. In the preferred embodiment, the second amplifier is a traveling-wave tube (TWT). A power supply is provided for operation of the second amplifier. A directional coupler is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter is provided for measuring the power delivered to the microwave furnace. A second power meter detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load. 5 figs.

Bible, D.W.; Lauf, R.J.

1994-06-14T23:59:59.000Z

262

Variable Crop Share Leases.  

E-Print Network [OSTI]

)OC lAL45.7 173 1. 1224 Texas Agricultural Extension Service The Texas A&M University System Daniel C. Pfannstiel,Director colleg e Station, Texas / f , ' '~ :';,; ,,: ''': ~ " k , -~. _Variable _Crop Share _Leases ... Marvin... Sartin and Ray Sammons* Renting or leasing farmland is part of many modern farming operations and increases average farm size in U. S. agriculture. Economies of size are vitally import ant to farm operations as they strive to cope with the continuous...

Sartin, Marvin; Sammons, Ray

1980-01-01T23:59:59.000Z

263

Variable depth core sampler  

DOE Patents [OSTI]

A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.

Bourgeois, P.M.; Reger, R.J.

1996-02-20T23:59:59.000Z

264

Stability of sunspots to convective motions. I. Adiabatic instability  

SciTech Connect (OSTI)

For determining the adiabatic stability of a uniform vertical field in an arbitrary stratification it is sufficient to consider the limit of infinitesimal horizontal wavelength. It is shown how the behavior of the instability can be estimated qualitatively from the dependence of the equipartition field strength on depth. Modes are calculated numerically for analytic stratification models and for a detailed sunspot stratification, including the effects of partial ionization. It is concluded that for the observed field strengths of umbrae the stratification is indeed unstable, with a growth time of about 18 minutes. The unstable eigenfunctions have a maximum at about 2300 km below the surface of the umbra and are about 3900 km deep. Deeper layers may also be unstable depending on unknown details of the stratification. A connection between fluting instability and convective instability is noted. 37 refs.

Moreno-Insertis, F.; Spruit, H.C. (Instituto de Astrofisica de Canarias, La Laguna (Spain); Max-Planck-Institut fuer Physik und Astrophysik, Garching (Germany, F.R.))

1989-07-01T23:59:59.000Z

265

Wind reversals in turbulent Rayleigh-Benard convection  

E-Print Network [OSTI]

The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-B\\'enard convection is theoretically analysed. The force and thermal balance on a single plume detached from the thermal boundary layer yields a set of coupled nonlinear equations, whose dynamics is related to the Lorenz equations. For Prandtl and Rayleigh numbers in the range $10^{-2} \\leq \\Pr \\leq 10^{3}$ and $10^{7} \\leq \\Ra \\leq 10^{12}$, the model has the following features: (i) chaotic reversals may be exhibited at Ra $\\geq 10^{7}$; (ii) the Reynolds number based on the root mean square velocity scales as $\\Re_{rms} \\sim \\Ra^{[0.41 ... 0.47]}$ (depending on Pr), and as $\\Re_{rms} \\sim \\Pr^{-[0.66 ... 0.76]}$ (depending on Ra); and (iii) the mean reversal frequency follows an effective scaling law $\\omega / (\

Francisco Fontenele Araujo; S. Grossmann; D. Lohse

2005-08-29T23:59:59.000Z

266

Operating temperatures for a convectively cooled recessed incandescent light fixture  

SciTech Connect (OSTI)

Test results are given for the operation of a recessed incandescent light fixture intended for residential use. The fixture is labeled for use in direct contact with attic thermal insulation. Temperature control of the powered fixture is provided by convective heat transfer from the ceiling side of the fixture. The fixture was operated at power levels up to two times the rated power of 75 watts and under thermal insulations up to R-40. In all operating configurations tested the fixture surface in contact with attic insulation was found to be less than 175/sup 0/C. The observed surface temperatures are judged to be safe for operation in contact with loose-fill or batt-type insulations. It was observed that the power leads inside one fixture configuration are exposed to temperatures as high as 168/sup 0/C. The electrical insulation could, therefore, have a limited life. The properties of the internal fixture wiring were not, however, studied in detail.

Yarbrough, D.W.; Toor, I.

1980-12-01T23:59:59.000Z

267

Apparatus for production of synthesis gas using convective reforming  

SciTech Connect (OSTI)

This patent describes a system for the steam reforming of hydrocarbons into a hydrogen-rich gas. It comprises a convective reformer device having indirect heat exchange means for partially reforming a feed mixture of hydrocarbons and steam; a steam reforming furnace having a radiant section, reforming tubes in the radiant section, and means for producing radiant heat for the further reforming of the partially reformed effluent; an auto-thermal reformer for fully reforming the effluent; conduit means for passing the partially reformed effluent; conduit means for passing the effluent; and conduit means for passing the fully reformed effluent to supply the heat of reaction for the partial reformation of the hydrocarbon-steam feed mixture.

Karafian, M.; Tsang, I.C.

1991-04-09T23:59:59.000Z

268

The structure and dynamics of patterns of Benard convection cells  

SciTech Connect (OSTI)

Benard-Marangoni convection, in containers with large aspect ratio, exhibits space-filling cellular structures, highly deformable, but crystallized. They contain dislocations and grain boundaries generated and moved by elementary topological transformations, and are subjected to a weak shear stress due to the earth's rotation. The cellular structure and its fluctuations are analyzed from a crystallographic viewpoint, by using two complementary approaches. One is a global analysis of cellular structures in cylindrical symmetry. Their structural stability and defect pattern are obtained as topological mode-locking of a continuous structural parameter. The other, a local, molecular dynamics of the cells, gives a realistic parametrization of the forces and the transformations by generalizing the Voronoi cell construction in one extra dimension. 23 refs., 8 figs.

Rivier, N. (Argonne National Lab., IL (USA) Imperial Coll. of Science and Technology, London (UK). Blackett Lab. Lausanne Univ. (Switzerland). Inst. de Physique Experimentale)

1990-08-01T23:59:59.000Z

269

TURBULENT CONVECTION IN STELLAR INTERIORS. III. MEAN-FIELD ANALYSIS AND STRATIFICATION EFFECTS  

SciTech Connect (OSTI)

We present three-dimensional implicit large eddy simulations of the turbulent convection in the envelope of a 5 M{sub Sun} red giant star and in the oxygen-burning shell of a 23 M{sub Sun} supernova progenitor. The numerical models are analyzed in the framework of one-dimensional Reynolds-Averaged Navier-Stokes equations. The effects of pressure fluctuations are more important in the red giant model, owing to larger stratification of the convective zone. We show how this impacts different terms in the mean-field equations. We clarify the driving sources of kinetic energy, and show that the rate of turbulent dissipation is comparable to the convective luminosity. Although our flows have low Mach numbers and are nearly adiabatic, our analysis is general and can be applied to photospheric convection as well. The robustness of our analysis of turbulent convection is supported by the insensitivity of the mean-field balances to linear mesh resolution. We find robust results for the turbulent convection zone and the stable layers in the oxygen-burning shell model, and robust results everywhere in the red giant model, but the mean fields are not well converged in the narrow boundary regions (which contain steep gradients) in the oxygen-burning shell model. This last result illustrates the importance of unresolved physics at the convective boundary, which governs the mixing there.

Viallet, Maxime [Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL (United Kingdom); Meakin, Casey; Mocak, Miroslav [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Arnett, David [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

2013-05-20T23:59:59.000Z

270

A new variable in flow analysis  

E-Print Network [OSTI]

We have used a simple spectrum distribution which was derived from a hydrodynamical equation\\cite{Csorgo} to fit the data of the STAR group. It is found that it can fit the $v_2$ of STAR group very well. We have found that $v_2$ is sensitive to both the effective temperature of particles and the expanding velocity. We have suggested a new variable ${\\bf z}$ to be used in the flow analysis. This new variable will measure the correlation of particles momentum components. We have also shown that one of the $x$ or $y$ direction in the reaction plane is the direction which has the largest variance.

Q. H. Zhang; L. Huo; W. N. Zhang

2006-06-20T23:59:59.000Z

271

Interactions between Cumulus Convection and Its Environment as Revealed by the MC3E Sounding Array  

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

This study attempts to understand interactions between midlatitude convective systems and their environments through a heat and moisture budget analysis using the sounding data collected from the Midlatitude Continental Convective Clouds Experiment (MC3E) in central Oklahoma. Distinct large-scale structures and diabatic heating and drying profiles are presented for cases of weaker and elevated thunderstorms as well as intense squall line and supercell thunderstorm events during the campaign. The elevated cell events were nocturnal convective systems occurring in an environment having low convective available potential energy (CAPE) and a very dry boundary layer. In contrast, deeper convective events happened during the morning into early afternoon within an environment associated with large CAPE and a near-saturated boundary layer. As the systems reached maturity, the diagnosed diabatic heating in the latter deep convective cases was much stronger and of greater vertical extent than the former. Both groups showed considerable diabatic cooling in the lower troposphere, associated with the evaporation of precipitation and low-level clouds. The horizontal advection of moisture also played a dominant role in moistening the lower troposphere, particularly for the deeper convective events, wherein the near surface southeasterly flow allows persistent low-level moisture return from the Gulf of Mexico to support convection. The moisture convergence often was present before these systems develop, suggesting a strong correlation between the large-scale moisture convergence and convection. Sensitivity tests indicated that the uncertainty in the surface precipitation and the size of analysis domain mainly affected the magnitude of these analyzed fields rather than their vertical structures.

Xie, Shaocheng [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Jensen, Michael P. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Zhang, Yunyan [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Giangrande, Scott E. [Brookhaven National Laboratory (BNL), Upton, NY (United States); McCoy, Renata [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Zhang, Minghua [Stony Brook Univ., Stony Brook, NY (United States)

2014-10-27T23:59:59.000Z

272

Mesoscale environmental models accompanying convection in the Texas HIPLEX region / by Mark Edward Humbert  

E-Print Network [OSTI]

with convection is upward motion at all levels with a maximum value just prior to max1mum convect1ve intensity. Days without convection showed a cont1nual vertical turbulent m1xing of moisture from a shallow boundary layer to the 700 mb level. Lack... of 4 g kg 1 are observed. The moisture content increases at the 22 Post Big Spring Midland Robert Lee 4 500 mb cn 0 O m 8 L. cn 6 x 4 2 700 mb . . ~ ''. ~' . ~ / r 12 10 850 mb 15 18 21 00 03 Time (GNT hours) Fig. 9. Time profiles...

Humbert, Mark Edward

1980-01-01T23:59:59.000Z

273

Convective Precipitation Variability as a Tool for General Circulation Model Analysis CHARLOTTE A. DEMOTT, DAVID A. RANDALL, AND MARAT KHAIROUTDINOV  

E-Print Network [OSTI]

. DEMOTT, DAVID A. RANDALL, AND MARAT KHAIROUTDINOV Department of Atmospheric Science, Colorado State

Randall, David A.

274

IMPACTS OF SOIL MOISTURE VARIABILITY ON CONVECTIVE PRECIPITATION IN THE CENTRAL PLAINS THROUGH LAND-ATMOSPHERE FEEDBACKS  

E-Print Network [OSTI]

A suite of regional climate model runs was conducted to examine the impacts of mean soil moisture and model resolution on precipitation events in the U.S. Central Plains, and to investigate the relative impacts of energy balance partitioning and net...

Jones, Aubrey R.

2008-08-20T23:59:59.000Z

275

On convergence of an iterative technique for solution of the implicit relationship between variables in the equations for moist convection  

E-Print Network [OSTI]

N)+M+ Sa (37) (3) a a (O) e a (O) and D) (3S~ R~ R~ ) Ds + (Ss 38~ R~ ) D) + (Ry M + Sr N)+N+ Sa (38) Ifn=3 Dq ? (Sg -6S R +Rq) Dq ? (4S~R~ - 4Sa R') D) + ~(Sj R~)M (2SyR~)N] + (SyM RyN) + M + Sa (39) and 12 D~ = (4SI3RI - I R ) Dk + (Sl ? 6SIRj... CONTINUE )rR I TE ( 6 r 9) I rRR ~ R ( rFC( I ) 9 FORFAT (Tier 'DR( ' r IZr ) r T3lrEl ~ 6 r(R ( TE (6 ~ I I ) I r IF, ( I, IC ( ( ) ll FOR& AT(Tle, rn I(' l2, ') ', T31, El4. 6, T6l, f14. 6, T9[, E14. 6) 200 CONTINUE 119o CONT(NUE RETURN ENO FUNCT...

Perry, Richard Allan

2012-06-07T23:59:59.000Z

276

Air-sea interaction at contrasting sites in the Eastern Tropical Pacific : mesoscale variability and atmospheric convection at 10°N  

E-Print Network [OSTI]

The role of ocean dynamics in driving air-sea interaction is examined at two contrasting sites on 125°W in the eastern tropical Pacific Ocean using data from the Pan American Climate Study (PACS) field program. Analysis ...

Farrar, J. Thomas (John Thomas), 1976-

2007-01-01T23:59:59.000Z

277

Thermophoretic transport of particles that act as volumetric heat sources in natural convection flow  

SciTech Connect (OSTI)

The natural convection boundary layer with suspended heat generating aerosol particles adjacent to a cooled, isothermal, vertical wall was investigated for the following circumstances: laminar and turbulent flow, large temperature differences between the wall and the fluid, stable thermal stratification far from the wall, and fluid participation in thermal radiation heat transfer. The deposition of aerosol particles by thermophoresis was investigated. A scaling analysis showed the negligible effect inside the boundary layer of the particulate heat source strengths of practical interest. Only the temperature of the fluid far from the wall is affected appreciably by the heat sources. The scaled boundary layer differential equations are transformed to a nonsimilarity form for numerical solution using two different methods. An expression for the ratio of mass transfer to heat transfer coefficients was developed to simplify the computation of thermophoretic particle deposition at the wall for the case of constant temperature conditions far from the wall. Variable thermophysical property effect for the three gases of steam, air, and hydrogen were investigated. A dimensionless ratio of transfer coefficients for large temperature differences and turbulent flow was computed as a product of the laminar constant property results and a ratio of the known thermophysical properties at the wall and far from the wall. An approximation of the laminar constant property results for all three gases is developed in terms of the known wall and fluid temperatures, Prandtl number, and a thermophoretic constant. This allows particle deposition to be computed from a known heat transfer coefficient without explicitly solving the particle conservation equation. 120 refs., 29 figs., 21 tabs.

Conklin, J.C.; Krane, R.J. (Oak Ridge National Lab., TN (USA); Tennessee Univ., Knoxville, TN (USA). Dept. of Mechanical and Aerospace Engineering)

1989-01-01T23:59:59.000Z

278

PHP: Constructs and Variables Introduction  

E-Print Network [OSTI]

PHP: Constructs and Variables Introduction This document describes: 1. the syntax and types of variables, 2. PHP control structures (i.e., conditionals and loops), 3. mixed-mode processing, 4. how to use one script from within another, 5. how to define and use functions, 6. global variables in PHP, 7

Vander Zanden, Brad

279

Physica D 143 (2000) 169186 Surface tension-driven convection patterns in two liquid layers  

E-Print Network [OSTI]

Physica D 143 (2000) 169­186 Surface tension-driven convection patterns in two liquid layers Anne a liquid layer with a free surface is heated from below, both surface tension gradients and buoyancy may

Texas at Austin. University of

280

A visualization comparison of convective flow boiling heat transfer augmentation devices  

E-Print Network [OSTI]

The qualitative effects of inset-table heat transfer phics. augmentation devices on vertical in-tube convective flow boiling flow regimes, transition mechanisms, and heat transfer are presented in this study. Three twisted tapes with twist ratios...

Lundy, Brian Franklin

1998-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Simulated diurnal rainfall physics in a multi-scale global climate model with embedded explicit convection  

E-Print Network [OSTI]

radiation-convection feedbacks are usually invoked to explain the open oceanocean] diurnal [rainfall] cycle can be qualita- tively accounted for by direct radiation-ocean is often maximized in the early morning hours, colloquially called the “Dynamic-Radiation-

Pritchard, Michael Stephen

2011-01-01T23:59:59.000Z

282

Numerical analysis of binary solid-liquid phase change with buoyancy and surface tension driven convection  

SciTech Connect (OSTI)

The effects of thermo/diffusocapillary convection on the solidification of aqueous NH{sub 4}Cl in a rectangular cavity have been simulated numerically using a newly developed continuum model. Diffusocapillary convection is negligible relative to thermocapillary convection, and for a 20 {times} 20 mm cavity in a one-gravity environment, thermocapillary effects are most pronounced during the early stages of solidification, when flow conditions are characterized by three major cells. One cell, driven by solutal buoyancy forces, extends from the mush region to the melt and separates top and bottom melt region cells driven primarily by surface tension and buoyancy forces, respectively. With increasing time, however, the top cell strengthens and eventually envelops the entire melt. In terms of the strength of the flow, the liquidus front morphology, and the amount of solid formed, final conditions differ only slightly from those predicted for pure thermal/solutal convection.

Incropera, F.P.; Engel, A.H.H. (Purdue Univ., Lafayette, IN (USA). Heat Transfer Lab.); Bennon, W.D. (Alcoa Technical Center, Alcoa Center, PA (US))

1989-01-01T23:59:59.000Z

283

Rheology and Convective Heat Transfer of Colloidal Gas Aphrons in Horizontal Minichannels  

E-Print Network [OSTI]

Single-phase convective heat transfer in microchannels: aand Newell, M. E. , 1967. Heat transfer in fully developed3 /s at 130 W. Water CGA Heat Transfer Coefficient, h (W/m 2

Tseng, H.; Pilon, L.; Warrier, G.

2006-01-01T23:59:59.000Z

284

Convective Heat Transfer Enhancement in Nanofluids: Real Anomaly or Analysis Artifact?  

E-Print Network [OSTI]

The nanofluid literature contains many claims of anomalous convective heat transfer enhancement in both turbulent and laminar flow. To put such claims to the test, we have performed a critical detailed analysis of the ...

Prabhat, Naveen

285

Radar, satellite, and lightning characteristics of select mesoscale convective systems in Texas  

E-Print Network [OSTI]

, the observation of high negative flash counts coincident with convective cores having small reflectivity lapse rates in the mixed phase region is consistent with the presence of large ice particles aloft. Positive CG flashes were mostly located in low reflectivity...

Toracinta, Ernest Richard

1995-01-01T23:59:59.000Z

286

Thermal perturbations caused by large impacts and consequences for mantle convection  

E-Print Network [OSTI]

We examine the effects of thermal perturbations on a convecting layer of incompressible fluid with uniform viscosity in the limit of infinite Prandtl number, for two upper boundary conditions (free- and no-slip) and heat ...

Watters, W. A.

287

Dusty gust fronts and their contributions to long-lived convection in West Africa/  

E-Print Network [OSTI]

To model and predict the behavior of West African storms and mesoscale convective systems (MCSs), we must understand the life cycle of gust fronts, which invariably accompany thunderstorms and often initiate them. In this ...

McGraw-Herdeg, Michael (Michael P.)

2010-01-01T23:59:59.000Z

288

Study of formation and convective transport of aerosols using optical diagnostic technique  

E-Print Network [OSTI]

. Part II investigates the characteristics of convective transport behavior of solid particles in virtual impactor (VI). The objective of part I is to establish correlations which offer predictions on atomized particle size of HTFs which are widely...

Kim, Tae-Kyun

2004-09-30T23:59:59.000Z

289

Convective cloud and rainfall processes over the Maritime Continent : simulation and analysis of the diurnal cycle  

E-Print Network [OSTI]

The Maritime Continent experiences strong moist convection, which produces significant rainfall and drives large fluxes of heat and moisture to the upper troposphere. Despite the importance of these processes to global ...

Gianotti, Rebecca L. (Rebecca Louise)

2013-01-01T23:59:59.000Z

290

Turbulent convection in the anelastic rotating sphere : a model for the circulation on the giant planets  

E-Print Network [OSTI]

This thesis studies the dynamics of a rotating compressible gas sphere, driven by internal convection, as a model for the dynamics on the giant planets. We develop a new general circulation model for the Jovian atmosphere, ...

Kaspi, Yohai

2008-01-01T23:59:59.000Z

291

The excitation of solar-like oscillations in a delta Scuti star by efficient envelope convection  

E-Print Network [OSTI]

Delta Scuti (delta Sct) stars are opacity-driven pulsators with masses of 1.5-2.5M$_{\\odot}$, their pulsations resulting from the varying ionization of helium. In less massive stars such as the Sun, convection transports mass and energy through the outer 30 per cent of the star and excites a rich spectrum of resonant acoustic modes. Based on the solar example, with no firm theoretical basis, models predict that the convective envelope in delta Sct stars extends only about 1 per cent of the radius, but with sufficient energy to excite solar-like oscillations. This was not observed before the Kepler mission, so the presence of a convective envelope in the models has been questioned. Here we report the detection of solar-like oscillations in the delta Sct star HD 187547, implying that surface convection operates efficiently in stars about twice as massive as the Sun, as the ad hoc models predicted.

Antoci, V; Campante, T L; Thygesen, A O; Moya, A; Kallinger, T; Stello, D; Grigahcène, A; Kjeldsen, H; Bedding, T R; Lüftinger, T; Christensen-Dalsgaard, J; Catanzaro, G; Frasca, A; De Cat, P; Uytterhoeven, K; Bruntt, H; Houdek, G; Kurtz, D W; Lenz, P; Kaiser, A; Van Cleve, J; Allen, C; Clarke, B D

2011-01-01T23:59:59.000Z

292

Observational Analysis of the Predictability of Mesoscale Convective Systems ISRAEL L. JIRAK AND WILLIAM R. COTTON  

E-Print Network [OSTI]

AND WILLIAM R. COTTON Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado merge into a large, long-lived organized convective system (Cotton and Anthes 1989). Thus, forecasting

293

Urban Aerosol Impacts on Downwind Convective Storms SUSAN C. VAN DEN HEEVER AND WILLIAM R. COTTON  

E-Print Network [OSTI]

Urban Aerosol Impacts on Downwind Convective Storms SUSAN C. VAN DEN HEEVER AND WILLIAM R. COTTON. 2004; Givati and Rosenfeld 2004; Molders and Olson 2004; Jirak and Cotton 2006); 2) increased surface

Collett Jr., Jeffrey L.

294

STUDY OF MHD MIXED CONVECTION IN THE DCLL BLANKET SMOLENTSEV Sergey1  

E-Print Network [OSTI]

, and ABDOU Mohamed3 1 University of California, Los Angeles, USA, sergey@fusion.ucla.edu 2 Laboratoire SIMAP, abdou@fusion.ucla.edu Abstract: Magnetohydrodynamic mixed convection associated with a non

Abdou, Mohamed

295

On the Diurnal Cycle of Deep Convection, High-Level Cloud, and Upper Troposphere Water Vapor in the Multiscale Modeling Framework  

SciTech Connect (OSTI)

The Multiscale Modeling Framework (MMF), also called ‘‘superparameterization’’, embeds a cloud-resolving model (CRM) at each grid column of a general circulation model to replace traditional parameterizations of moist convection and large-scale condensation. This study evaluates the diurnal cycle of deep convection, high-level clouds, and upper troposphere water vapor by applying an infrared (IR) brightness temperature (Tb) and a precipitation radar (PR) simulator to the CRM column data. Simulator results are then compared with IR radiances from geostationary satellites and PR reflectivities from the Tropical Rainfall Measuring Mission (TRMM). While the actual surface precipitation rate in the MMF has a reasonable diurnal phase and amplitude when compared with TRMM observations, the IR simulator results indicate an inconsistency in the diurnal anomalies of high-level clouds between the model and the geostationary satellite data. Primarily because of its excessive high-level clouds, the MMF overestimates the simulated precipitation index (PI) and fails to reproduce the observed diurnal cycle phase relationships among PI, high-level clouds, and upper troposphere relative humidity. The PR simulator results show that over the tropical oceans, the occurrence fraction of reflectivity in excess of 20 dBZ is almost 1 order of magnitude larger than the TRMM data especially at altitudes above 6 km. Both results suggest that the MMF oceanic convection is overactive and possible reasons for this bias are discussed. However, the joint distribution of simulated IR Tb and PR reflectivity indicates that the most intense deep convection is found more often over tropical land than ocean, in agreement with previous observational studies.

Zhang, Yunyan; Klein, Stephen A.; Liu, Chuntao; Tian, Baijun; Marchand, Roger T.; Haynes, J. M.; McCoy, Renata; Zhang, Yuying; Ackerman, Thomas P.

2008-08-22T23:59:59.000Z

296

A study of the relationship between certain moisture parameters and severe convective storms in central Oklahoma  

E-Print Network [OSTI]

A STUDY OF THE RELATIONSHIP BETWEEN CERTAIN MOISTURE PARAMETERS AND SEVERE CONVECTIVE STORMS IN CENTRAL OKLAHOMA A Thesis by CARVEN ALLEN SCOTT Submitted to the Graduate College of Texas ASM University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE May 1977 Major Subject: Meteorology A STUDY OF THE RELATIONSHIP BETWEEN CERTAIN MOISTURE PARAMETERS AND SEVERE CONVECTIVE STORMS IN CENTRAL OKLAHOMA A Thesis by CARVEN ALLEN SCOTT Approved as to style...

Scott, Carven Allen

2012-06-07T23:59:59.000Z

297

Remote Measurement of Heat Flux from Power Plant Cooling Lakes  

SciTech Connect (OSTI)

Laboratory experiments have demonstrated a correlation between the rate of heat loss q? from an experimental fluid to the air above and the standard deviation ? of the thermal variability in images of the fluid surface. These experimental results imply that q? can be derived directly from thermal imagery by computing ?. This paper analyses thermal imagery collected over two power plant cooling lakes to determine if the same relationship exists. Turbulent boundary layer theory predicts a linear relationship between q? and ? when both forced (wind driven) and free (buoyancy driven) convection are present. Datasets derived from ground- and helicopter-based imagery collections had correlation coefficients between ? and q? of 0.45 and 0.76, respectively. Values of q? computed from a function of ? and friction velocity u* derived from turbulent boundary layer theory had higher correlations with measured values of q? (0.84 and 0.89). This research may be applicable to the problem of calculating losses of heat from the ocean to the atmosphere during high-latitude cold-air outbreaks because it does not require the information typically needed to compute sensible, evaporative, and thermal radiation energy losses to the atmosphere.

Garrett, A.; Kurzeja, R.; Villa-Aleman, E.; Bollinger, J.

2013-01-01T23:59:59.000Z

298

Effects of Radiative Diffusion on Thin Flux Tubes in Turbulent Solar-like Convection  

E-Print Network [OSTI]

We study the combined effects of convection and radiative diffusion on the evolution of thin magnetic flux tubes in the solar interior. Radiative diffusion is the primary supplier of heat to convective motions in the lower convection zone, and it results in a heat input per unit volume of magnetic flux tubes that has been ignored by many previous thin flux tube studies. We use a thin flux tube model subject to convection taken from a rotating spherical shell of turbulent, solar-like convection as described by Weber, Fan, and Miesch (2011, Astrophys. J., 741, 11; 2013, Solar Phys., 287, 239), now taking into account the influence of radiative heating on flux tubes of large-scale active regions. Our simulations show that flux tubes of less than or equal to 60 kG subject to solar-like convective flows do not anchor in the overshoot region, but rather drift upward due to the increased buoyancy of the flux tube earlier in its evolution as a result of the inclusion of radiative diffusion. Flux tubes of magnetic fie...

Weber, Maria A

2015-01-01T23:59:59.000Z

299

Respective roles of shallow convection and stratiform rainfall on the simulation of Madden-Julian Oscillation.  

SciTech Connect (OSTI)

Respective Roles of Shallow Convection and Stratiform Rainfall on the Simulation of Madden Julian Oscillation Joshua Xiouhua Fu IPRC, SOEST, University of Hawaii The IPRC/UH Hybrid-coupled GCM (HcGCM), which combined ECHAM-4 AGCM with UH intermediate ocean model, produces robust Tropical Intra-Seasonal Oscillations including the boreal-winter MJO and boreal-summer Monsoon Intra-Seasonal Oscillation. In this study, two sets of sensitivity experiments (i.e., short-term retrospective forecast of one MJO event observed during TOGA COARE and long-term free integrations) have been carried out to understand the respective roles of shallow-convection and stratiform rainfall on the simulations and predictions of the MJO. Major findings are summarized as following: Shallow-convection ahead of MJO deep convection moistens the lower-troposphere and preconditions the movement of the MJO. Present study shows that this process is very important to the eastward propagating speed of the MJO. A significant fraction of stratiform rainfall (~30%; stratiform part vs. total rainfall) is needed for ECHAM-4 to have a robust MJO. The above findings suggest that in addition to deep convection, shallow convection and stratiform rainfall needs to be well represented in conventional GCMs to ensure a robust model MJO.

Fu, Joshua Xiouhua [IPRC/SOEST/UH; Wang, Bin [IPRC& DM/SOEST/UH; Yeh, Hsi-Chyi

2010-03-15T23:59:59.000Z

300

Convective flow measurements in a heated cavity using pulsed laser velocimetry with digital image processing  

E-Print Network [OSTI]

. This is essentially the trapezoidal sheet shown in figure 4. The thickness of the beam remains on the order of 1-1. 5 13 x-v plane z-y plane First Lens Focal Point Second Lens Third Lens Fig. 4. Laser light passing through a trio of piano-convex cylindrical...2 U3 v1 v2 3 u4 u5 u7 u8 u6 u9 v4 v 5 v7 v8 Figure 24. Pixel positions in relation to vector components. Expressing equation (15) spatially, where uij and vij are gray level values ranging from 0 to 255 at position i and j of each region...

Chavez, Hector Luis

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Eddy-resolving Lidar Measurements and Numerical Simulations of the Convective Internal Boundary Layer  

E-Print Network [OSTI]

in speed. The vertical gradient of wind-speed decreases offshore because of strong vertical mixing caused correlation functions and winds derived from horizontal (PPI) and vertical (RHI) scans of the VIL during Lake.4 0.5 0.6 0.7 DOWNSTREAM WIND SPEEDS FROM RHI SCANS ON 13 JANUARY 1998 SPATIALLY RESOLVED 5-m WINDS

Eloranta, Edwin W.

302

Radial convection of finite ion temperature, high amplitude plasma blobs  

SciTech Connect (OSTI)

We present results from simulations of seeded blob convection in the scrape-off-layer of magnetically confined fusion plasmas. We consistently incorporate high fluctuation amplitude levels and finite Larmor radius (FLR) effects using a fully nonlinear global gyrofluid model. This is in line with conditions found in tokamak scrape-off-layers (SOL) regions. Varying the ion temperature, the initial blob width, and the initial amplitude, we found an FLR dominated regime where the blob behavior is significantly different from what is predicted by cold-ion models. The transition to this regime is very well described by the ratio of the ion gyroradius to the characteristic gradient scale length of the blob. We compare the global gyrofluid model with a partly linearized local model. For low ion temperatures, we find that simulations of the global model show more coherent blobs with an increased cross-field transport compared to blobs simulated with the local model. The maximal blob amplitude is significantly higher in the global simulations than in the local ones. When the ion temperature is comparable to the electron temperature, global blob simulations show a reduced blob coherence and a decreased cross-field transport in comparison with local blob simulations.

Wiesenberger, M., E-mail: Matthias.Wiesenberger@uibk.ac.at; Kendl, A. [Institute for Ion Physics and Applied Physics, Association EURATOM-ÖAW, University of Innsbruck, A-6020 Innsbruck (Austria); Madsen, J. [Association EURATOM-DTU, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark)

2014-09-15T23:59:59.000Z

303

Convective Heating of the LIFE Engine Target During Injection  

SciTech Connect (OSTI)

Target survival in the hostile, high temperature xenon environment of the proposed Laser Inertial Fusion Energy (LIFE) engine is critical. This work focuses on the flow properties and convective heat load imposed upon the surface of the indirect drive target while traveling through the xenon gas. While this rarefied flow is traditionally characterized as being within the continuum regime, it is approaching transition where conventional CFD codes reach their bounds of operation. Thus ANSYS, specifically the Navier-Stokes module CFX, will be used in parallel with direct simulation Monte Carlo code DS2V and analytically and empirically derived expressions for heat transfer to the hohlraum for validation. Comparison of the viscous and thermal boundary layers of ANSYS and DS2V were shown to be nearly identical, with the surface heat flux varying less than 8% on average. From the results herein, external baffles have been shown to reduce this heat transfer to the sensitive laser entrance hole (LEH) windows and optimize target survival independent of other reactor parameters.

Holdener, D S; Tillack, M S; Wang, X R

2011-10-24T23:59:59.000Z

304

Constructing a Merged Cloud-Precipitation Radar Dataset for Tropical Convective Clouds during the DYNAMO/AMIE Experiment at Addu Atoll  

SciTech Connect (OSTI)

To improve understanding of the convective processes key to the Madden-Julian-Oscillation (MJO) initiation, the Dynamics of the MJO (DYNAMO) and Atmospheric Radiation Measurement MJO Investigation Experiment (AMIE) collected four months of observations from three radars, the S-band Polarization Radar (S-Pol), the C-band Shared Mobile Atmospheric Research & Teaching Radar (SMART-R), and Ka-band Zenith Radar (KAZR) on Addu Atoll in the tropical Indian Ocean. This study compares the measurements from the S-Pol and SMART-R to those from the more sensitive KAZR in order to characterize the hydrometeor detection capabilities of the two scanning precipitation radars. Frequency comparisons for precipitating convective clouds and non-precipitating high clouds agree much better than non-precipitating low clouds for both scanning radars due to issues in ground clutter. On average, SMART-R underestimates convective and high cloud tops by 0.3 to 1.1 km, while S-Pol underestimates cloud tops by less than 0.4 km for these cloud types. S-Pol shows excellent dynamic range in detecting various types of clouds and therefore its data are well suited for characterizing the evolution of the 3D cloud structures, complementing the profiling KAZR measurements. For detecting non-precipitating low clouds and thin cirrus clouds, KAZR remains the most reliable instrument. However, KAZR is attenuated in heavy precipitation and underestimates cloud top height due to rainfall attenuation 4.3% of the time during DYNAMO/AMIE. An empirical method to correct the KAZR cloud top heights is described, and a merged radar dataset is produced to provide improved cloud boundary estimates, microphysics and radiative heating retrievals.

Feng, Zhe; McFarlane, Sally A.; Schumacher, Courtney; Ellis, Scott; Comstock, Jennifer M.; Bharadwaj, Nitin

2014-05-16T23:59:59.000Z

305

Selection automatique de variables pertinentes  

E-Print Network [OSTI]

S´election automatique de variables pertinentes Vers la d´ecouverte de nouvelles modalit´es sensori-motrices corr´elations entre ses variables sensori-motrices afin d'apprendre `a r´esoudre sa t^ache d

Boyer, Edmond

306

Complex hydraulic and substrate variables limit freshwater mussel species richness and abundance  

E-Print Network [OSTI]

Complex hydraulic and substrate variables limit freshwater mussel species richness and abundance. We examined how substrate and complex hydraulic variables limit the distribution of freshwater mussels. We sampled mussels and measured substrate and hydraulic variables (at low and high flows) at 6

Vaughn, Caryn

307

Polluting of Winter Convective Clouds upon Transition from Ocean Inland Over Central California: Contrasting Case Studies  

SciTech Connect (OSTI)

In-situ aircraft measurements of aerosol chemical and cloud microphysical properties were conducted during the CalWater campaign in February and March 2011 over the Sierra Nevada Mountains and the coastal waters of central California. The main objective was to elucidate the impacts of aerosol properties on clouds and precipitation forming processes. In order to accomplish this, we compared contrasting cases of clouds that ingested aerosols from different sources. The results showed that clouds containing pristine oceanic air had low cloud drop concentrations and started to develop rain 500 m above their base. This occurred both over the ocean and over the Sierra Nevada, mainly in the early morning when the radiatively cooled stable continental boundary layer was decoupled from the cloud base. Supercooled rain dominated the precipitation that formed in growing convective clouds in the pristine air, up to the -21°C isotherm level. A contrasting situation was documented in the afternoon over the foothills of the Sierra Nevada, when the clouds ingested high pollution aerosol concentrations produced in the Central Valley. This led to slow growth of the cloud drop effective radius with height and suppressed and even prevented the initiation of warm rain while contributing to the development of ice hydrometeors in the form of graupel. Our results show that cloud condensation and ice nuclei were the limiting factors that controlled warm rain and ice processes, respectively, while the unpolluted clouds in the same air mass produced precipitation quite efficiently. These findings provide the motivation for deeper investigations into the nature of the aerosols seeding clouds.

Rosenfeld, Daniel; Chemke, Rei; Prather, Kimberly; Suski, Kaitlyn; Comstock, Jennifer M.; Schmid, Beat; Tomlinson, Jason M.; Jonsson, Haf

2014-01-01T23:59:59.000Z

308

Anomalous Scaling and Refined Similarity of an Active Scalar in a Model of Homogeneous Turbulent Convection  

E-Print Network [OSTI]

Anomalous scaling in the statistics of an active scalar in homogeneous turbulent convection is studied using a dynamical shell model. We extend refined similarity ideas for homogeneous and isotropic turbulence to homogeneous turbulent convection and attribute the origin of the anomalous scaling to variations of the entropy transfer rate. We verify the consequences and thus the validity of our hypothesis by showing that the conditional statistics of the active scalar and the velocity at fixed values of entropy transfer rate are not anomalous but have simple scaling with exponents given by dimensional considerations, and that the intermittency corrections are given by the scaling exponents of the moments of the entropy transfer rate.

Emily S. C. Ching; W. C. Cheng

2007-11-07T23:59:59.000Z

309

Scale/Analytical Analyses of Freezing and Convective Melting with Internal Heat Generation  

SciTech Connect (OSTI)

Using a scale/analytical analysis approach, we model phase change (melting) for pure materials which generate constant internal heat generation for small Stefan numbers (approximately one). The analysis considers conduction in the solid phase and natural convection, driven by internal heat generation, in the liquid regime. The model is applied for a constant surface temperature boundary condition where the melting temperature is greater than the surface temperature in a cylindrical geometry. The analysis also consider constant heat flux (in a cylindrical geometry).We show the time scales in which conduction and convection heat transfer dominate.

Ali S. Siahpush; John Crepeau; Piyush Sabharwall

2013-07-01T23:59:59.000Z

310

Convective-Resolving Regional Climate Simulations for the Amazon Basin: Comparison with TRMM Rainfall Data  

E-Print Network [OSTI]

), Clark and Peltier (1977), and Clark (1979). It is worth mentioning that the technology at the time limited their domain size to a few tens of kilometers and their runtimes to a few hours at the spatial and temporal resolutions required to simulate a... single convective cell. In the decade after the introduction of the three-dimensional CM, CM experiments began to focus on mesoscale convective systems such as squall lines. Weisman et al. (1988) and Rotunno et al. (1988) used an evolved version...

Kinney, Nichole 1987-

2012-08-21T23:59:59.000Z

311

Scaling laws for convection and jet speeds in the giant planets Adam P. Showman a,b,,1  

E-Print Network [OSTI]

Scaling laws for convection and jet speeds in the giant planets Adam P. Showman a,b,,1 , Yohai in these models, but no previous theories have been advanced to explain these trends. Here, we show using simple arguments that if convective release of potential energy pumps the jets and viscosity damps them, the mean

312

A new predictive dynamic model describing the effect of1 the ambient temperature and the convective heat transfer2  

E-Print Network [OSTI]

and the convective heat transfer2 coefficient on bacterial growth3 4 H. Ben Yaghlenea,b* , I. Leguerinela , M. Hamdib Ratkowsky "square root" model and a simplified two-parameter20 heat transfer model regarding an infinite air temperature, the convective heat transfer22 coefficient and the growth parameters of the micro

Paris-Sud XI, Université de

313

Modeling the coupling between free and forced convection in a vertical permeable slot: implications for the heat  

E-Print Network [OSTI]

1 Modeling the coupling between free and forced convection in a vertical permeable slot numerical study of the coupling between forced and free convective flows has been performed by considering: implications for the heat production of an Enhanced Geothermal System Arnaud Batailléa , Pierre Genthona

Paris-Sud XI, Université de

314

Chaotic flow in a 2D natural convection loop with heat flux boundaries William F. Louisos a,b,  

E-Print Network [OSTI]

the nonlinear dynamics of unstable convection in a 2D thermal convection loop (i.e., thermosyphon) with heat behavior and residence time in a cir- culatory direction are explored and described for the various thermal-storms depicted as a classic `bow echo' on radar [3]; land and sea breezes as a result of differential heating

Danforth, Chris

315

Quantum information with modular variables  

E-Print Network [OSTI]

We introduce a novel strategy, based on the use of modular variables, to encode and deterministically process quantum information using states described by continuous variables. Our formalism leads to a general recipe to adapt existing quantum information protocols, originally formulated for finite dimensional quantum systems, to infinite dimensional systems described by continuous variables. This is achieved by using non unitary and non-gaussian operators, obtained from the superposition of gaussian gates, together with adaptative manipulations in qubit systems defined in infinite dimensional Hilbert spaces. We describe in details the realization of single and two qubit gates and briefly discuss their implementation in a quantum optical set-up.

A. Ketterer; S. P. Walborn; A. Keller; T. Coudreau; P. Milman

2014-06-24T23:59:59.000Z

316

Pulsational instability domain of Delta Scuti variables  

E-Print Network [OSTI]

An updated theoretical instability domain of the Delta Scuti star models in the Hertzsprung-Russell diagram, in the log g - log Teff diagram and in diagrams for dereddened uvby-beta photometric indices is presented. The sensitivity of both the position of the evolutionary tracks and the Blue Edge of the instability domain to changes in the chemical composition parameters (X, Z) and to changes in the convection theory parameters (mixing-length in the stellar envelope, the extent of the overshooting from the convective core) is discussed.

A. A. Pamyatnykh

2000-05-12T23:59:59.000Z

317

Update this !!! What measures climate? A variety of variables including their variability and  

E-Print Network [OSTI]

with higher humidity and precipitation. #12;4 #12;5 For two identical beams of sunlight (solar energy of the Earth's axis causes the solar beam at B to become more concentrated, thereby providing more energy than regions of Australia. #12;999 The constant supply of radiative energy from the sun would continue to heat

Allan, Richard P.

318

Measuring Cost Variability in Provision of Transit Service  

E-Print Network [OSTI]

Comprehensive Transit Performance Indicators. UCTC WorkingModal Transit Performance Indicators. Ph.D. dissertation.

Taylor, Brian D.; Garrett, Mark; Iseki, Hiroyuki

2010-01-01T23:59:59.000Z

319

Measuring Spatial Variability of Vapor Flux to Characterize Vadose...  

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

different monitoring points within the interrogated area will be a function of the geospatial positions of the points relative to the source location. A series of flow-cell...

320

Variable metric conjugate gradient methods  

SciTech Connect (OSTI)

1.1 Motivation. In this paper we present a framework that includes many well known iterative methods for the solution of nonsymmetric linear systems of equations, Ax = b. Section 2 begins with a brief review of the conjugate gradient method. Next, we describe a broader class of methods, known as projection methods, to which the conjugate gradient (CG) method and most conjugate gradient-like methods belong. The concept of a method having either a fixed or a variable metric is introduced. Methods that have a metric are referred to as either fixed or variable metric methods. Some relationships between projection methods and fixed (variable) metric methods are discussed. The main emphasis of the remainder of this paper is on variable metric methods. In Section 3 we show how the biconjugate gradient (BCG), and the quasi-minimal residual (QMR) methods fit into this framework as variable metric methods. By modifying the underlying Lanczos biorthogonalization process used in the implementation of BCG and QMR, we obtain other variable metric methods. These, we refer to as generalizations of BCG and QMR.

Barth, T.; Manteuffel, T.

1994-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Interaction between surface and atmosphere in a convective boundary layer /  

E-Print Network [OSTI]

II.4) to measure vertical profiles of wind speed, direction,a larger vertical gradient of horizontal wind-speed in theintense vertical mixing, resulting in constant wind speed,

Garai, Anirban

2013-01-01T23:59:59.000Z

322

FREE CONVECTIVE LAMINAR FLOW WITHIN THE TROMBE WALL CHANNEL  

E-Print Network [OSTI]

NM 87545, pp. 201-222. J.D. Balcomb, J.C. Hedstrom, R.D.wall have been measured by Balcomb, et al [2J. The problem

Akbari, H.

2011-01-01T23:59:59.000Z

323

Marangoni convection induced by a nonlinear temperature-dependent surface tension  

E-Print Network [OSTI]

23 Marangoni convection induced by a nonlinear temperature-dependent surface tension A. Cloot and G'instabilité de Marangoni dans une mince lame horizontale de fluide lorsque la tension de surface est une fonction ofthe surface- tension with respect to the temperature is studied. This behaviour is typical of some

Paris-Sud XI, Université de

324

Time-independent square patterns in surface-tension-driven Benard convection  

E-Print Network [OSTI]

Time-independent square patterns in surface-tension-driven Be´nard convection Michael F. Schatza The transition between hexagonal and square patterns is investigated in laboratory experiments on surface-tension, the transition from hexagons to other patterns was unexplored for the surface-tension-driven regime of Be

Texas at Austin. University of

325

Under consideration for publication in J. Fluid Mech. 1 Stressed horizontal convection  

E-Print Network [OSTI]

in the Gullmarfjord on the west coast of Sweden. When the wind swept over the fjord, the water at the surface flowed to the suggestion of Munk & Wunsch (1998) that mechanical energy sources -- such as the wind stress observed by Sandstr¨om (1908) -- are necessary to sustain the ocean circulation. Recent work on horizontal convection

Young, William R.

326

Eects of convection instability due to incompatibility between ocean dynamics and surface forcings  

E-Print Network [OSTI]

- bility between a surface temperature climatology and a given ocean model, into which the climatology by thermal and wind forcing only. Initially, the temperature climatology is forcefully assimilated climatology. In areas characterized by sharp oceanic fronts and high convective activity, the OGCM, due

Paris-Sud XI, Université de

327

Three Dimensional Simulation of Rayleigh-Bénard Convection for Rapid Microscale Polymerase Chain Reaction  

E-Print Network [OSTI]

Rayleigh-Bénard convection has been extensively studied in literature owing to its ubiquitous nature. However, most of the studies have been confined to geometries where the aspect ratio of the cylinder was less than 1. Here we study the motion...

Muddu, Radha Malini Gowri

2012-02-14T23:59:59.000Z

328

Deep convection in the Irminger Sea forced by the Greenland tip jet  

E-Print Network [OSTI]

Deep convection in the Irminger Sea forced by the Greenland tip jet Robert S. Pickart*, Michael A atmospheric jet known as the Greenland tip jet, which forms periodically in the lee of Cape Farewell, Greenland, and is associated with elevated heat flux and strong wind stress curl. Using a history of tip

Pickart, Robert S.

329

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

SciTech Connect (OSTI)

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

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

2010-04-15T23:59:59.000Z

330

Using CASA IP1 to Diagnose Kinematic and Microphysical Interactions in a Convective Storm  

E-Print Network [OSTI]

bulk hydrometeor identification and dual-Doppler wind retrievals. Comparisons are made with the nearby-band radars are used to observe a convective storm. A fuzzy logic hydrometeor identification algorithm the type of echoes in the network based on storm identification al- gorithms, then allocates radars

Rutledge, Steven

331

Can a Convective Cloud Feedback Help to Eliminate Winter Sea Ice at High CO2 Concentrations?  

E-Print Network [OSTI]

have remote effects on global climate as well. Accurate forecasting of winter sea ice has significantCan a Convective Cloud Feedback Help to Eliminate Winter Sea Ice at High CO2 Concentrations? DORIAN) ABSTRACT Winter sea ice dramatically cools the Arctic climate during the coldest months of the year and may

Tziperman, Eli

332

Influence of Sea Surface Temperature on Humidity and Temperature in the Outflow of Tropical Deep Convection  

E-Print Network [OSTI]

-Service Aircraft (MOZAIC) project are analyzed in the vicinity of deep convective outflow to study the variationsInfluence of Sea Surface Temperature on Humidity and Temperature in the Outflow of Tropical Deep upper-tropospheric temperature and humidity by the Mea- surement of Ozone and Water Vapor by Airbus In

Johnson, Richard H.

333

Small-scale magnetic buoyancy and magnetic pumping effects in a turbulent convection  

E-Print Network [OSTI]

We determine the nonlinear drift velocities of the mean magnetic field and nonlinear turbulent magnetic diffusion in a turbulent convection. We show that the nonlinear drift velocities are caused by the three kinds of the inhomogeneities, i.e., inhomogeneous turbulence; the nonuniform fluid density and the nonuniform turbulent heat flux. The inhomogeneous turbulence results in the well-known turbulent diamagnetic and paramagnetic velocities. The nonlinear drift velocities of the mean magnetic field cause the small-scale magnetic buoyancy and magnetic pumping effects in the turbulent convection. These phenomena are different from the large-scale magnetic buoyancy and magnetic pumping effects which are due to the effect of the mean magnetic field on the large-scale density stratified fluid flow. The small-scale magnetic buoyancy and magnetic pumping can be stronger than these large-scale effects when the mean magnetic field is smaller than the equipartition field. We discuss the small-scale magnetic buoyancy and magnetic pumping effects in the context of the solar and stellar turbulent convection. We demonstrate also that the nonlinear turbulent magnetic diffusion in the turbulent convection is anisotropic even for a weak mean magnetic field. In particular, it is enhanced in the radial direction. The magnetic fluctuations due to the small-scale dynamo increase the turbulent magnetic diffusion of the toroidal component of the mean magnetic field, while they do not affect the turbulent magnetic diffusion of the poloidal field.

I. Rogachevskii; N. Kleeorin

2006-05-18T23:59:59.000Z

334

Dynamo Action in the Solar Convection Zone and Tachocline: Pumping and Organization of Toroidal Fields  

E-Print Network [OSTI]

We present the first results from three-dimensional spherical shell simulations of magnetic dynamo action realized by turbulent convection penetrating downward into a tachocline of rotational shear. This permits us to assess several dynamical elements believed to be crucial to the operation of the solar global dynamo, variously involving differential rotation resulting from convection, magnetic pumping, and amplification of fields by stretching within the tachocline. The simulations reveal that strong axisymmetric toroidal magnetic fields (about 3000 G in strength) are realized within the lower stable layer, unlike in the convection zone where fluctuating fields are predominant. The toroidal fields in the stable layer possess a striking persistent antisymmetric parity, with fields in the northern hemisphere largely of opposite polarity to those in the southern hemisphere. The associated mean poloidal magnetic fields there have a clear dipolar geometry, but we have not yet observed any distinctive reversals or latitudinal propagation. The presence of these deep magnetic fields appears to stabilize the sense of mean fields produced by vigorous dynamo action in the bulk of the convection zone.

Matthew Browning; Mark S. Miesch; Allan Sacha Brun; Juri Toomre

2006-09-06T23:59:59.000Z

335

3D convection simulations of the outer layers of the Sun using realistic physics  

E-Print Network [OSTI]

This paper describes a series of 3D simulations of shallow inefficient convection in the outer layers of the Sun. The computational domain is a closed box containing the convection-radiation transition layer, located at the top of the solar convection zone. The most salient features of the simulations are that: i)The position of the lower boundary can have a major effect on the characteristics of solar surface convection (thermal structure, kinetic energy and turbulent pressure). ii)The width of the box has only a minor effect on the thermal structure, but a more significant effect on the dynamics (rms velocities). iii)Between the surface and a depth of 1 Mm, even though the density and pressure increase by an order of magnitude, the vertical correlation length of vertical velocity is always close to 600 km. iv) In this region the vertical velocity cannot be scaled by the pressure or the density scale height. This casts doubt on the applicability of the mixing length theory, not only in the superadiabatic layer, but also in the adjacent underlying layers. v) The final statistically steady state is not strictly dependent on the initial atmospheric stratification.

F. J. Robinson; P. Demarque; L. H. Li; S. Sofia; Y. -C. Kim; K. L. Chan; D. B. Guenther

2002-12-12T23:59:59.000Z

336

10.12 CONVECTION INITIATION AND MISOCYCLONE DEVELOMENT: IS THERE A LINK ?  

E-Print Network [OSTI]

Kingsmill·, and Carl Young £ · University of Colorado, CIRES, Boulder, Colorado Desert Research Institute to horizontal shear instabilities can produce wave pattern that produce small scale ( 4 km) vertical vortic- ity with the initiation of deep convection along the Florida Peninsula using a net- work of anemometers. Since

337

Compact fluorescent lamp using horizontal and vertical insulating septums and convective venting geometry  

DOE Patents [OSTI]

A novel design is described for a compact fluorescent lamp, including a lamp geometry which will increase light output and efficacy of the lamp in a base down operating position by providing horizontal and vertical insulating septums positioned in the ballast compartment of the lamp to provide a cooler coldspot. Selective convective venting provides additional cooling of the ballast compartment. 9 figs.

Siminovitch, M.

1998-02-10T23:59:59.000Z

338

Vertical structure of tropical oceanic convective clouds and its relation to precipitation  

E-Print Network [OSTI]

data are collocated with precipitation rates from the Advanced Microwave Scanning Radiometer (AMSR high tops that are nearly two km deeper than moderately raining or non- raining high clouds. Rain rate.1029/2007GL032811. 1. Introduction [2] Tropical convection plays an important role in the energy and moisture

Hartmann, Dennis

339

Parameterized Mesoscale Forcing Mechanisms for Initiating Numerically Simulated Isolated Multicellular Convection  

E-Print Network [OSTI]

Multicellular Convection ADRIAN M. LOFTUS* School of Meteorology, University of Oklahoma, Norman, Oklahoma DANIEL B. WEBER Center for Analysis and Prediction of Storms, University of Oklahoma, Norman, Oklahoma CHARLES A. DOSWELL III Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma

Doswell III, Charles A.

340

TACKLEY ET AL.:THERMO-CHEMICAL PHILOSOPHY Numerical and laboratory studies of mantle convection: Philosophy,  

E-Print Network [OSTI]

TACKLEY ET AL.:THERMO-CHEMICAL PHILOSOPHY 1 Numerical and laboratory studies of mantle convection: Philosophy, accomplishments and thermo-chemical structure and evolution Paul J. Tackley Department of Earth how the solid parts of Earth and other terrestrial planets work. Here, the general philosophy

Tackley, Paul J.

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Numerical computation of 3D heat transfer in complex parallel convective exchangers using generalized Graetz modes  

E-Print Network [OSTI]

Numerical computation of 3D heat transfer in complex parallel convective exchangers using insights into the most con- tributing structure to exchanges and transfers. Several examples of heat, whilst many other can be found in a recent review [12]. As quoted in [12] conjugate heat transfer

Paris-Sud XI, Université de

342

The Ratio of Helium- to Hydrogen-Atmosphere White Dwarfs: Direct Evidence for Convective Mixing  

E-Print Network [OSTI]

We determine the ratio of helium- to hydrogen-atmosphere white dwarf stars as a function of effective temperature from a model atmosphere analysis of the infrared photometric data from the Two Micron All Sky Survey combined with available visual magnitudes. Our study surpasses any previous analysis of this kind both in terms of the accuracy of the Teff determinations as well as the size of the sample. We observe that the ratio of helium- to hydrogen-atmosphere white dwarfs increases gradually from a constant value of ~0.25 between Teff = 15,000 K and 10,000 K to a value twice as large in the range 10,000 > Teff > 8000 K, suggesting that convective mixing, which occurs when the bottom of the hydrogen convection zone reaches the underlying convective helium envelope, is responsible for this gradual transition. The comparison of our results with an approximate model used to describe the outcome of this convective mixing process implies hydrogen mass layers in the range log M_H/M_tot = -10 to -8 for about 15% of the DA stars that survived the DA to DB transition near Teff ~ 30,000 K, the remainder having presumably more massive layers above log M_H/M_tot ~ -6.

P. -E. Tremblay; P. Bergeron

2007-10-04T23:59:59.000Z

343

Dynamic RadiativeConvective Equilibria Using GCM Column Physics ISAAC M. HELD  

E-Print Network [OSTI]

Dynamic Radiative­Convective Equilibria Using GCM Column Physics ISAAC M. HELD NOAA and Oceanic Sciences, Department of Geosciences, Princeton University, Princeton, New Jersey BRUCE WYMAN NOAA author address: Dr. Isaac M. Held, NOAA/Geo- physical Fluid Dynamics Laboratory, Princeton University

344

EulerianEulerian two-phase numerical simulation of nanofluid laminar forced convection in a microchannel  

E-Print Network [OSTI]

by a cooling system to guarantee their appropriate performance. One possible way to cool these devises canEulerian­Eulerian two-phase numerical simulation of nanofluid laminar forced convection August 2010 Accepted 5 August 2010 Keywords: Nanofluid Microchannel Two-phase Laminar Heat transfer a b

Harting, Jens

345

PHYSICS OF FLUIDS 25, 094105 (2013) Onset of convection with fluid compressibility  

E-Print Network [OSTI]

2013; published online 25 September 2013) The density increase from carbon dioxide (CO2) dissolution. The convection is important for both CO2 sequestration in deep saline aquifers and CO2 improved oil recovery from to interface movement may be much more pronounced in hydro- carbons than in water. This could have important

Firoozabadi, Abbas

346

The effect of shear on heat budgets in a simulated Mesoscale Convective System  

E-Print Network [OSTI]

in the lowest 2.5 km varying from 10-25 m s?¹. A fourth simulation was conducted using the weak wind shear profile and incorporating ice microphysics. An analysis domain was produced every two hours for the northern and southern portions of the convective line...

Shaw, Justin David

2000-01-01T23:59:59.000Z

347

Magneto-convective models of red dwarfs: constraints imposed by the lithium abundance  

E-Print Network [OSTI]

Magnetic fields impede the onset of convection, thereby altering the thermal structure of a convective envelope in a low mass star: this has an effect on the amount of lithium depletion in a magnetized star. In order to quantify this effect, we have applied a magneto-convective model to two low mass stars for which lithium abundances and precise structural parameters are known: YY Gem and CU Cnc. For both stars, we have obtained models which satisfy empirical constraints on the following parameters: R, L, surface magnetic field strength, and Li abundance. In the case of YY Gem, we have obtained a model which satisfies the empirical constraints with an internal magnetic field of several megagauss: such a field strength is within the range of a dynamo where the field energy is in equipartition with rotational energy deep inside the convection zone. However, in the case of CU Cnc, the Li requires an internal magnetic field which is probably too strong for a dynamo origin: we suggest possible alternatives which m...

MacDonald, J

2015-01-01T23:59:59.000Z

348

The performance of PEM fuel cells fed with oxygen through the free-convection mode  

E-Print Network [OSTI]

The performance of PEM fuel cells fed with oxygen through the free-convection mode Pei-Wen Li; accepted 27 September 2002 Abstract The feasibility and restrictions of feeding oxygen to a PEM fuel cell in the fuel cell. Experimental tests were conducted for one PEM fuel cell stack and two single PEM fuel cell

349

Modeling the observed proton aurora and ionospheric convection responses to changes in the IMF clock angle  

E-Print Network [OSTI]

Modeling the observed proton aurora and ionospheric convection responses to changes in the IMF clock angle: 1. Persistence of cusp proton aurora K. Throp, M. Lockwood,1 B. S. Lanchester, and S. K employ a numerical model of cusp ion precipitation and proton aurora emission to fit variations

Lockwood, Mike

350

Reverse convection and cusp proton aurora: Cluster, polar and image observation  

E-Print Network [OSTI]

Reverse convection and cusp proton aurora: Cluster, polar and image observation Q.-G. Zong a,b,*, TT) at Earth. Cusp proton aurora was caused by the leading phase of the CME. Cusp proton aurora generally of the cusp proton aurora shifted about 30° from dawnside to duskside when IMF By changed from À10 to 5 n

California at Berkeley, University of

351

EQUILIBRIUM VS. ACTIVATION CONTROL OF LARGE-SCALE VARIATIONS OF TROPICAL DEEP CONVECTION  

E-Print Network [OSTI]

convective cloud systems. This essay highlights the distinction between processes which supply moisture separations of the LSVDC problem are reviewed. Scale separation, though rigorous, is artificial, since net cloudiness, are exam- ined as examples. Lower boundary flux enhancements and deep lifting exert both

Mapes, Brian

352

Movement of oxygen from the atmosphere to the mitochondria occurs via several convective and diffusive steps  

E-Print Network [OSTI]

4111 Movement of oxygen from the atmosphere to the mitochondria occurs via several convective and diffusive steps (Weibel et al., 1981). In mammals, maximal rate of oxygen consumption (VOmax) is not limited by any one step of the oxygen cascade; rather limitations to VOmax are distributed across all steps

Bennett, Albert F.

353

Convectively Coupled Waves Propagating along an Equatorial ITCZ JULIANA DIAS AND OLIVIER PAULUIS  

E-Print Network [OSTI]

Convectively Coupled Waves Propagating along an Equatorial ITCZ JULIANA DIAS AND OLIVIER PAULUIS waves propagate at the moist gravity wave speed (about 15 m s21 ), whereas for a narrow ITCZ, the propagation speed is comparable to the dry gravity wave (about 50 m s21 ). It is also shown that a Kelvin wave

Pauluis, Olivier M.

354

High-latitude ionospheric convection models derived from Defense Meteorological Satellite Program ion drift  

E-Print Network [OSTI]

Vladimir O. Papitashvili Space Physics Research Laboratory, University of Michigan, Ann Arbor, Michigan to the average solar wind (i.e., the ``quasi-viscous'' interaction) and to changes in the IMF By, Bz 0, and Bz, plasma convection, current systems 1. Introduction [2] Earth's magnetosphere is immersed in the solar

Michigan, University of

355

Evaluation of mesoscale convective systems in South America using multiple satellite products and an objectbased approach  

E-Print Network [OSTI]

and an objectbased approach E. M. C. Demaria,1 D. A. Rodriguez,2 E. E. Ebert,3 P. Salio,4 F. Su,5 and J. B. Valdes1 to precipitation was mitigating the effect of the errors. Citation: Demaria, E. M. C., D. A. Rodriguez, E. E. Ebert, P. Salio, F. Su, and J. B. Valdes (2011), Evaluation of mesoscale convective systems in South

Ebert, Beth

356

A phenomenological model of thermal-hydraulics of convective boiling during the quenching of hot rod bundles  

SciTech Connect (OSTI)

After completion of the thermal-hydraulic model developed in a companion paper, the authors performed developmental assessment calculation of the model using steady-state and transient post-critical heat flux (CHF) data. This paper discusses the results of those calculations. The overall interfacial drag model predicted reasonable drag coefficients for both the nucleate boiling and the inverted annular flow (IAF) regimes. The predicted pressure drops agreed reasonably well with the measured data of two transient experiments, CCTF Run 14 and a Lehigh reflood test. The thermal-hydraulic model for post-CHF convective heat transfer predicted the rewetting velocities reasonably well for both experiments. The predicted average slope of the wall temperature traces for these tests showed reasonable agreement with the measured data, indicating that the transient-calculated precursory cooling rates agreed with measured data. The hot-patch model, in conjunction with the other thermal-hydraulic models, was capable of modeling the Winfrith post-CHF hot-patch experiments. The hot-patch model kept the wall temperatures at the specified levels in the hot-patch regions and did not allow any quench-front propagation from either the bottom or the top of the test section. The interfacial heat-transfer model tended to slightly underpredict the vapor temperatures. The maximum difference between calculated and measured vapor temperatures was 20%, with a 10% difference for the remainder of the runs considered. The wall-to-fluid heat transfer was predicted reasonably well, and the predicted wall temperatures were in reasonable agreement with measured data with a maximum relative error of less than 13%.

Unal, C.; Nelson, R.

1991-01-01T23:59:59.000Z

357

Constitutive correlations for wire-wrapped subchannel analysis under forced and mixed convection conditions. Part 1. [LMFBR  

SciTech Connect (OSTI)

A simple subchannel analysis method based on the ENERGY series of codes, ENERGY-IV, has been established for predicting the temperature field in a single isolated wire-wrapped Liquid Metal Fast Breeder Reactor (LMFBR) subassembly under steady state forced and mixed convection conditions. The ENERGY-IV is a totally empirical code employed for fast running purposes and requires well calibrated lead length averaged input parameters to achieve satisfactory predictions. These input parameters were identified to be the inlet flow split parameters, the subchannel friction factors, the interchannel mixing parameters, the conduction shape factor, and the transverse velocity at the edge gap. Experiments were performed in a 37-pin wire-wrapped rod bundle with a geometry between that of a typical LMFBR fuel subassembly and blanket subassembly for filling the gap in the available data base for the input parameters. The isokinetic extraction method for measuring subchannel velocity, the pitot-static probe for measuring pressure drop, and the salt tracer injection method for estimating the interchannel mixing, were used in these experiments.

Cheng, S.K.; Todreas, N.E.

1984-08-01T23:59:59.000Z

358

GRANULATION IN RED GIANTS: OBSERVATIONS BY THE KEPLER MISSION AND THREE-DIMENSIONAL CONVECTION SIMULATIONS  

SciTech Connect (OSTI)

The granulation pattern that we observe on the surface of the Sun is due to hot plasma rising to the photosphere where it cools down and descends back into the interior at the edges of granules. This is the visible manifestation of convection taking place in the outer part of the solar convection zone. Because red giants have deeper convection zones than the Sun, we cannot a priori assume that their granulation is a scaled version of solar granulation. Until now, neither observations nor one-dimensional analytical convection models could put constraints on granulation in red giants. With asteroseismology, this study can now be performed. We analyze {approx}1000 red giants that have been observed by Kepler during 13 months. We fit the power spectra with Harvey-like profiles to retrieve the characteristics of the granulation (timescale {tau}{sub gran} and power P{sub gran}). We search for a correlation between these parameters and the global acoustic-mode parameter (the position of maximum power, {nu}{sub max}) as well as with stellar parameters (mass, radius, surface gravity (log g), and effective temperature (T{sub eff})). We show that {tau}{sub eff}{proportional_to}{nu}{sup -0.89}{sub max} and P{sub gran}{proportional_to}{nu}{sup -1.90}{sub max}, which is consistent with the theoretical predictions. We find that the granulation timescales of stars that belong to the red clump have similar values while the timescales of stars in the red giant branch are spread in a wider range. Finally, we show that realistic three-dimensional simulations of the surface convection in stars, spanning the (T{sub eff}, log g) range of our sample of red giants, match the Kepler observations well in terms of trends.

Mathur, S. [High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO 80307 (United States); Hekker, S. [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, P.O. Box 94249, 1090 GE Amsterdam (Netherlands); Trampedach, R. [JILA, University of Colorado and National Institute of Standards and Technology, 440 UCB, Boulder, CO 80309 (United States); Ballot, J. [Institut de Recherche en Astrophysique et Planetologie, CNRS, 14 avenue E. Belin, 31400 Toulouse (France); Kallinger, T. [Institute for Astronomy (IfA), University of Vienna, Tuerkenschanzstrasse 17, 1180 Vienna (Austria); Buzasi, D. [Eureka Scientific, 2452 Delmer Street Suite 100, Oakland, CA 94602-3017 (United States); Garcia, R. A. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot-IRFU/SAp, 91191 Gif-sur-Yvette Cedex (France); Huber, D.; Bedding, T. R.; Stello, D. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Jimenez, A.; Regulo, C. [Dpto de Astrofisica, Universidad de La Laguna, 38206, Tenerife (Spain); Mosser, B. [LESIA, UMR8109, Universite Pierre et Marie Curie, Universite Denis Diderot, Obs. de Paris, 92195 Meudon Cedex (France); Elsworth, Y.; Chaplin, W. J.; Hale, S. J. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); De Ridder, J. [Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001 Leuven (Belgium); Kinemuchi, K. [Bay Area Environmental Research Inst./NASA Ames Research Center, Moffett Field, CA 94035 (United States); Kjeldsen, H. [Danish AsteroSeismology Centre, Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C (Denmark); Mullally, F. [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States)

2011-11-10T23:59:59.000Z

359

IS ACTIVE REGION CORE VARIABILITY AGE DEPENDENT?  

SciTech Connect (OSTI)

The presence of both steady and transient loops in active region cores has been reported from soft X-ray and extreme-ultraviolet observations of the solar corona. The relationship between the different loop populations, however, remains an open question. We present an investigation of the short-term variability of loops in the core of two active regions in the context of their long-term evolution. We take advantage of the nearly full Sun observations of STEREO and Solar Dynamics Observatory spacecraft to track these active regions as they rotate around the Sun multiple times. We then diagnose the variability of the active region cores at several instances of their lifetime using EIS/Hinode spectral capabilities. We inspect a broad range of temperatures, including for the first time spatially and temporally resolved images of Ca XIV and Ca XV lines. We find that the active region cores become fainter and steadier with time. The significant emission measure at high temperatures that is not correlated with a comparable increase at low temperatures suggests that high-frequency heating is viable. The presence, however, during the early stages, of an enhanced emission measure in the ''hot'' (3.0-4.5 MK) and ''cool'' (0.6-0.9 MK) components suggests that low-frequency heating also plays a significant role. Our results explain why there have been recent studies supporting both heating scenarios.

Ugarte-Urra, Ignacio [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2012-12-10T23:59:59.000Z

360

The impact of uncertainty and risk measures  

E-Print Network [OSTI]

3.3 A Measure Based on GARCH Process . . . . . 3.4 Measuresand flexibly. Then, I introduce GARCH-based measure, SRISK,directly in the two-variable GARCH-in- Mean VAR using US and

Jo, Soojin; Jo, Soojin

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Logarithmic Bounds for Infinite Prandtl Number Rotating Convection  

E-Print Network [OSTI]

is how much of the total heat transfer is due to convec- tion. The natural measure of this quantity on the forcing parameter [1] - [6], although it has been observed that rotation plays a nontrivial role as well, Chandrasekhar [8]). This is a 1 #12; system of equations coupling

Constantin, Peter

362

Evaluation of convection-permitting model simulations of cloud populations associated with the Madden-Julian Oscillation using data collected during the AMIE/DYNAMO field campaign  

SciTech Connect (OSTI)

Regional cloud permitting model simulations of cloud populations observed during the 2011 ARM Madden Julian Oscillation Investigation Experiment/ Dynamics of Madden-Julian Experiment (AMIE/DYNAMO) field campaign are evaluated against radar and ship-based measurements. Sensitivity of model simulated surface rain rate statistics to parameters and parameterization of hydrometeor sizes in five commonly used WRF microphysics schemes are examined. It is shown that at 2 km grid spacing, the model generally overestimates rain rate from large and deep convective cores. Sensitivity runs involving variation of parameters that affect rain drop or ice particle size distribution (more aggressive break-up process etc) generally reduce the bias in rain-rate and boundary layer temperature statistics as the smaller particles become more vulnerable to evaporation. Furthermore significant improvement in the convective rain-rate statistics is observed when the horizontal grid-spacing is reduced to 1 km and 0.5 km, while it is worsened when run at 4 km grid spacing as increased turbulence enhances evaporation. The results suggest modulation of evaporation processes, through parameterization of turbulent mixing and break-up of hydrometeors may provide a potential avenue for correcting cloud statistics and associated boundary layer temperature biases in regional and global cloud permitting model simulations.

Hagos, Samson M.; Feng, Zhe; Burleyson, Casey D.; Lim, Kyo-Sun; Long, Charles N.; Wu, Di; Thompson, Gregory

2014-11-12T23:59:59.000Z

363

Operating Reserves and Variable Generation  

SciTech Connect (OSTI)

This report tries to first generalize the requirements of the power system as it relates to the needs of operating reserves. It also includes a survey of operating reserves and how they are managed internationally in system operations today and then how new studies and research are proposing they may be managed in the future with higher penetrations of variable generation.

Ela, E.; Milligan, M.; Kirby, B.

2011-08-01T23:59:59.000Z

364

HEART RATE VARIABILITY AS DETERMINISM WITH JUMP STOCHASTIC PARAMETERS  

E-Print Network [OSTI]

HEART RATE VARIABILITY AS DETERMINISM WITH JUMP STOCHASTIC PARAMETERS JIONGXUAN ZHENG, JOE SKUFCA, AND ERIK BOLLT§ Abstract. We use measured heart rate information (RR intervals) to develop a one with persistence which causes the heart rate and rhythm system to wander about a bifurcation point. We propose

Bollt, Erik

365

Rfrences bibliographiques [1] R. E. Kelly, The onset and development of Rayleigh-Bnard convection in shear flows: a  

E-Print Network [OSTI]

1 Références bibliographiques [1] R. E. Kelly, The onset and development of Rayleigh Publication, London, 1977, pp. 65-79. [2] R. E. Kelly, The onset and development of thermal convection

Paris-Sud XI, Université de

366

Mixed convection and high-pressure low-flow steam cooling data from a 64-rod bundle  

SciTech Connect (OSTI)

Heat transfer data were obtained from low flow steam cooling experiments in a partially uncovered 64-rod bundle. These tests indicated that free convection effects were superimposed on the laminar and turbulent forced convection heat transfer. This paper describes the influence of buoyancy on laminar and turbulent forced convection heat transfer coefficients. Mechanisms due to buoyancy which alter the local heat transfer are summarized. Criteria indicating the importance of buoyancy on laminar and turbulent upflow in a vertical pipe were developed and compared to other criteria found in the literature. These criteria were used to determine the steam cooling data with significant buoyancy influence. Data with buoyancy influence were compared to mixed convection correlations and to a numerical study for rod bundles.

Sozer, A.

1984-01-01T23:59:59.000Z

367

Cloud-to-ground lightning characteristics of warm season Mesoscale Convection Systems in the Central United States: 1992-1993  

E-Print Network [OSTI]

This study provides a detailed analysis of cloud-to-aphics. ground (CG) lightning flashes within individual Mesoscale Convective Systems (MCSs) that occurred in the Central United States during May-August of 1992 and 1993. Analysis of the CG...

Hoeth, Brian Richard

2012-06-07T23:59:59.000Z

368

The evolution of total lightning and radar reflectivity characteristics of two mesoscale convective systems over Houston, Texas  

E-Print Network [OSTI]

originated in the convective or transition regions. Both in-situ charging mechanisms created by the development of the mesoscale updraft and charge advection by the front-to-rear flow likely contribute to the increased electrification and lightning...

Hodapp, Charles Lee

2009-05-15T23:59:59.000Z

369

Quarterly Journal of the Royal Meteorological Society Q. J. R. Meteorol. Soc. (2013) Phenomenology of Sahelian convection observed in Niamey  

E-Print Network [OSTI]

Quarterly Journal of the Royal Meteorological Society Q. J. R. Meteorol. Soc. (2013) Phenomenology SM. 2013. Phenomenology of Sahelian convection observed in Niamey during the early monsoon. Q. J. R

Guichard, Francoise

370

Segregation of Particulate Solids: Segregation via Convection S. Luding(*/**), J. Duran(*), E. Cl'ement(*), J. Rajchenbach(*)  

E-Print Network [OSTI]

they examine granular convection with nuclear magnetic resonance imaging methods. Eventually, detailed are discussed: Segregation in a powder bed, at the surface of a powder bed and in a fluidized powder bed

Luding, Stefan

371

Momentum transport processes in the stratiform regions of mesoscale convective systems over the western Pacific warm pool  

E-Print Network [OSTI]

Momentum transport by the stratiform components of mesoscale convective systems (MCSs) during the Tropical Ocean–Global Atmosphere Coupled Ocean–Atmosphere Response Experiment in December 1992 is investigated using a ...

Mechem, David B.; Chen, Shuyi S.; Houze, Robert A. Jr.

2006-04-01T23:59:59.000Z

372

Influence of a coronal envelope as a free boundary to global convective dynamo simulations  

E-Print Network [OSTI]

We explore the effects of an outer stably stratified coronal envelope on rotating turbulent convection, differential rotation, and large-scale dynamo action in spherical wedge models of the Sun. We solve the compressible magnetohydrodynamic equations in a two-layer model with unstable stratification below the surface, representing the convection zone, and a stably stratified outer layer, the coronal envelope. The interface emulates essentially a free surface. We compare with models that have no coronal envelope. The presence of a coronal envelope is found to modify the Reynolds stress and the $\\Lambda$-effect resulting in a weaker and non-cylindrical differential rotation. This is related to the reduced latitudinal temperature variations, which are caused by and dependent on the Coriolis force. Some simulations develop a rudimentary near-surface shear layer, which we can relate to a sign change of the meridional Reynolds stress term in the thermal wind balance equation. Furthermore, the presence of a free sur...

Warnecke, Jörn; Käpylä, Maarit J; Brandenburg, Axel

2015-01-01T23:59:59.000Z

373

A Compressible High-Order Unstructured Spectral Difference Code for Stratified Convection in Rotating Spherical Shells  

E-Print Network [OSTI]

We present a novel and powerful Compressible High-ORder Unstructured Spectral-difference (CHORUS) code for simulating thermal convection and related fluid dynamics in the interiors of stars and planets. The computational geometries are treated as rotating spherical shells filled with stratified gas. The hydrodynamic equations are discretized by a robust and efficient high-order Spectral Difference Method (SDM) on unstructured meshes. The computational stencil of the spectral difference method is compact and advantageous for parallel processing. CHORUS demonstrates excellent parallel performance for all test cases reported in this paper, scaling up to 12,000 cores on the Yellowstone High-Performance Computing cluster at NCAR. The code is verified by defining two benchmark cases for global convection in Jupiter and the Sun. CHORUS results are compared with results from the ASH code and good agreement is found. The CHORUS code creates new opportunities for simulating such varied phenomena as multi-scale solar co...

Wang, Junfeng; Miesch, Mark S

2015-01-01T23:59:59.000Z

374

A Theory of Non-Local Mixing Length Convection. III. Comparing Theory and Numerical Experiment  

E-Print Network [OSTI]

We solve the nonlocal convection equations. The solutions for four model problems are compared with results of GSPH simulations. In each case we test two closure schemes: 1) where third moments are defined by the diffusion approximation; and 2) where the full third moment equations are used and fourth moments are defined by a modified form of the quasi-normal approximation. In overshooting models, the convective flux becomes negative shortly after the stability boundary. The negative amplitude remains small, and the temperature gradient in the overshooting zone has nearly the radiative value. Turbulent velocities decay by a factor of $e$ after $0.5$--$1.5\\ell$, depending on the model, where $\\ell$ is the mixing length. Turbulent viscosity is more important than negative buoyancy in decelerating overshooting fluid blobs. These predictions are consistent with helioseismology.

Scott Grossman

1995-09-08T23:59:59.000Z

375

ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scm_forcing)  

SciTech Connect (OSTI)

The constrained variational objective analysis approach described in Zhang and Lin [1997] and Zhang et al. [2001]was used to derive the large-scale single-column/cloud resolving model forcing and evaluation data set from the observational data collected during Midlatitude Continental Convective Clouds Experiment (MC3E), which was conducted during April to June 2011 near the ARM Southern Great Plains (SGP) site. The analysis data cover the period from 00Z 22 April - 21Z 6 June 2011. The forcing data represent an average over the 3 different analysis domains centered at central facility with a diameter of 300 km (standard SGP forcing domain size), 150 km and 75 km, as shown in Figure 1. This is to support modeling studies on various-scale convective systems.

Xie, Shaocheng; McCoy, Renata; Zhang, Yunyan

2012-10-25T23:59:59.000Z

376

Numerical investigation of the convection of heat-emitting liquid reactor materials taking stratification into account  

SciTech Connect (OSTI)

Convective heat transfer to a reactor vessel following core destruction is analyzed. Fuel fragment and structural materials are assumed to melt either mix uniformly or stratify. The Navier-Stokes equations were solved numerically with a rectangular coarse difference grid, neglecting the negligibly small contribution of the laminar boundary layer. Calculations for different levels of volume heat release showed that integral heat fluxes at the lateral and top surfaces of the melt are virtually independent of the convective flow scenario. However, the maximum heat flux on the lateral surface is approximately 1.5 times higher for the homogeneous case than for the stratified case. The higher heat flux could result in larger mechanical loads on the reactor vessel, requiring more cooling of the reactor vessel outer surface. 12 refs., 4 figs.

Likhanskii, V.V.; Loboiko, A.I.; Khoruzhii, O.V.

1994-11-01T23:59:59.000Z

377

Millennial-scale stable oscillations between sea ice and convective deep water formation  

E-Print Network [OSTI]

During the last ice age there were several quasi-periodic abrupt warming events. The climatic effects of the so-called Dansgaard-Oeschger (DO) events were felt globally, although the North Atlantic experienced the largest and most abrupt temperature anomalies. Similar but weaker oscillations also took place during the interglacial period. This paper proposes an auto-oscillatory mechanism between sea ice and convective deep water formation in the north Atlantic as the source of the persistent cycles. A simple dynamical model is constructed by coupling and slightly modifying two existing models of ocean circulation and sea ice. The model exhibits mixed mode oscillations, consisting of decadal scale small amplitude oscillations, and a large amplitude relaxation fluctuation. The decadal oscillations occur due to the insulating effect of sea ice and leads to periodic ventilation of heat from the polar ocean. Gradually an instability builds up in the polar column and results in an abrupt initiation of convection an...

Saha, Raj

2015-01-01T23:59:59.000Z

378

The First Second of a Type-II Supernova: Convection, Accretion, and Shock Propagation  

E-Print Network [OSTI]

One- and two-dimensional hydrodynamical simulations of neutrino-driven supernova explosions are discussed. The simulations cover the phase between the stagnation of the prompt shock and about one second after core bounce. Systematic variation of the neutrino fluxes from the neutrino sphere shows that the explosion energy, explosion time scale, initial mass of the protoneutron star, and explosive nucleosynthesis of iron-group elements depend sensitively on the strength of the neutrino heating during the first few 100 ms after shock formation. Convective overturn in the neutrino-heated region behind the shock is a crucial help for the explosion only in a narrow window of neutrino luminosities. Here powerful explosions can be obtained only in the multi-dimensional case. For higher core-neutrino fluxes also spherically symmetrical models yield energetic explosions, while for lower luminosities even with convection no strong explosions occur.

H. -Thomas Janka; Ewald Mueller

1995-03-03T23:59:59.000Z

379

Natural convection phenomena in a nuclear power plant during a postulated TMLB' accident  

SciTech Connect (OSTI)

After the TMI (Three Mile Island) accident, there has been significant interest in analyzing and understanding the phenomena that may occur in a PWR (Pressurized Water Reactor) accident which may lead to partial or total core meltdown and degradation. Natural convection is one of the important phenomena. In the present paper the results of two numerical simulations of (1) four-loop PWR and (2) three-loop PWR are presented. The simulations were performed with the COMMIX(2) computer code. Our analysis shows that in severe accident scenarios, natural convection phenomena does occur and that it helps to delay core degradation by transferring decay heat from the reactor core to other internal structures of the reactor system. The amount of heat transfer and delay in core degradation depends on the geometry and internal structures of the system and on the events of an accident.

Domanus, H.M.; Schmitt, R.C.; Sha, W.T.; Shah, V.L.; Han, J.T.

1987-01-01T23:59:59.000Z

380

ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scm_forcing)  

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

The constrained variational objective analysis approach described in Zhang and Lin [1997] and Zhang et al. [2001]was used to derive the large-scale single-column/cloud resolving model forcing and evaluation data set from the observational data collected during Midlatitude Continental Convective Clouds Experiment (MC3E), which was conducted during April to June 2011 near the ARM Southern Great Plains (SGP) site. The analysis data cover the period from 00Z 22 April - 21Z 6 June 2011. The forcing data represent an average over the 3 different analysis domains centered at central facility with a diameter of 300 km (standard SGP forcing domain size), 150 km and 75 km, as shown in Figure 1. This is to support modeling studies on various-scale convective systems.

Xie, Shaocheng; McCoy, Renata; Zhang, Yunyan

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Dependence of maximum realizable convective energy on horizontal scale in a one-dimensional entraining jet model  

E-Print Network [OSTI]

DEPENDENCE OF MAXIMUM REALIZABLE CONVECTIVE ENERGY ON HORIZONTAL SCALE IN A ONE ? DIMENSIONAL ENTRAINING JET MODEL A Thesis by DAVID BILLINGS WOLFF Submitted to the Graduate College of Twas A&M University in partial fulfillment... on Horizontal Scale in a One ? Dimensional Entraining Jet Model. (May 1988) David Billings Wolff, B. S. , Texas AkM University Chairman of Advisory Committe: Phanindramohan Das A one dimensional numerical model of convective clouds was implemented in which...

Wolff, David Billings

1988-01-01T23:59:59.000Z

382

Description and preliminary validation of a model for natural convection heat and air transport in passive solar buildings  

SciTech Connect (OSTI)

We have proposed a transient, quasi-two-dimensional, numerical model for interzone heat flow and airflow in passive solar buildings. The paths for heat flow and airflow are through connecting apertures such as doorways, hallways, and stairways. The model includes the major features that influence interzone convection as determined from the results of our flow visualization tests and temperature and airflow measurements taken in more than a dozen passive solar buildings. The model includes laminar and turbulent quasi-steady boundary-layer equations at vertical heated or cooled walls which are coupled to a one-dimensional core model for each zone. The cores in each zone exchange air and energy through the aperture which is modelled by a Bernoulli equation. Preliminary results from the model are in general agreement with data obtained in full-scale buildings and laboratory experiments. The model predicts room-core temperature stratification of about 2/sup 0/C/m (1.1/sup 0/ F/ft) and maximum aperture velocities of 0.08 m/s (15 ft/min.) for a room-to-room temperature difference of 1/sup 0/F.

Jones, G.F.; Balcomb, J.D.

1985-01-01T23:59:59.000Z

383

Method and Appartus for Calibrating a Linear Variable Differential Transformer  

SciTech Connect (OSTI)

A calibration apparatus for calibrating a linear variable differential transformer (LVDT) having an armature positioned in au LVDT armature orifice, and the armature able to move along an axis of movement. The calibration apparatus includes a heating mechanism with an internal chamber, a temperature measuring mechanism for measuring the temperature of the LVDT, a fixture mechanism with an internal chamber for at least partially accepting the LVDT and for securing the LVDT within the heating mechanism internal chamber, a moving mechanism for moving the armature, a position measurement mechanism for measuring the position of the armature, and an output voltage measurement mechanism. A method for calibrating an LVDT, including the steps of powering the LVDT; heating the LVDT to a desired temperature; measuring the position of the armature with respect to the armature orifice; and measuring the output voltage of the LVDT.

Pokrywka, Robert J.

2005-01-18T23:59:59.000Z

384

Method and apparatus for calibrating a linear variable differential transformer  

DOE Patents [OSTI]

A calibration apparatus for calibrating a linear variable differential transformer (LVDT) having an armature positioned in au LVDT armature orifice, and the armature able to move along an axis of movement. The calibration apparatus includes a heating mechanism with an internal chamber, a temperature measuring mechanism for measuring the temperature of the LVDT, a fixture mechanism with an internal chamber for at least partially accepting the LVDT and for securing the LVDT within the heating mechanism internal chamber, a moving mechanism for moving the armature, a position measurement mechanism for measuring the position of the armature, and an output voltage measurement mechanism. A method for calibrating an LVDT, including the steps of: powering the LVDT; heating the LVDT to a desired temperature; measuring the position of the armature with respect to the armature orifice; and measuring the output voltage of the LVDT.

Pokrywka, Robert J. (North Huntingdon, PA)

2005-01-18T23:59:59.000Z

385

Pre-convective environmental conditions indicative of non-tornadic severe thunderstorm winds over Southeast Florida  

E-Print Network [OSTI]

thunderstorm wind events over Southeast Florida during the period of study. Upper-air data were obtained for several stations on and around the Florida peninsula. These stations include: Key West, Florida (EYW), West Palm Beach, Florida (PBI), Tampa Bay...PRE-CONVECTIVE ENVIRONMENTAL CONDITIONS INDICATIVE OF NON-TORNADIC SEVERE THUNDERSTORM WINDS OVER SOUTHEAST FLORIDA A Thesis by JEFFREY MICHAEL WILHELM Submitted to the Graduate College of Texas ARM University in partial fulfillment...

Wilhelm, Jeffrey Michael

1987-01-01T23:59:59.000Z

386

Mixed Convection in the VHTR in the Event of a LOFA  

SciTech Connect (OSTI)

The US Department of Energy, Office of Nuclear Energy (DOE-NE) is supporting the development of a very high temperature reactor (VHTR) concept as the primary focus of it next generation nuclear power plant (NGNP) program. The VHTR is cooled by forcing helium downwards through the core into the lower plenum and out the hot duct. In the event that the coolant circulators are lost, the driving pressure drop across the core will reduce to zero and there will be the opportunity for natural circulation to occur. During the time that the circulators are powering down, the heat transfer in the core from the graphite blocks to the helium coolant will transform from turbulent forced convection to mixed convection, where buoyancy effects become important, to free or natural convection, where buoyancy is dominant. Analysis of the nature of the forced, mixed and free convection is best done using computational fluid dynamic (CFD) software that can provide fine details of the flow and heat transfer. However, CFD analysis involves approximations in the results because of the finite nature of the spatial and temporal discretizations required, the inexact nature of the turbulence models that are used and the finite precision of the computers employed. Therefore, it is necessary to validate the CFD computations. Validation is accomplished by comparing results from specific CFD computations to experimental data that have been taken specifically for the purpose of validation and that are related to the physical phenomena in question. The present report examines the flow and heat transfer parameters (dimensionless numbers) that characterize the flow and reports ranges for their values based on specific CFD studies performed for the VHTR.

Richard W. Johnson

2012-05-01T23:59:59.000Z

387

Aircraft Observations of Sub-cloud Aerosol and Convective Cloud Physical Properties  

E-Print Network [OSTI]

of Department, Kenneth Bowman December 2009 Major Subject: Atmospheric Sciences iii iii ABSTRACT Aircraft Observations of Sub-Cloud Aerosol and Convective Cloud Physical Properties. (December 2009) Duncan Axisa, B.Ed., University of Malta; B... but for vertical velocity (ms-1). Negative values are updraft and positive values are downdraft ........................................... 30 18 Cloud droplet size distribution (dN/dlogD, cm-3) for 1Hz cloud penetration data...

Axisa, Duncan

2011-02-22T23:59:59.000Z

388

Solar dynamo models with alpha-effect and turbulent pumping from local 3D convection calculations  

E-Print Network [OSTI]

(abridged) Results from kinematic solar dynamo models employing alpha-effect and turbulent pumping from local convection calculations are presented. We estimate the magnitude of these effects to be around 2-3 m/s. The rotation profile of the Sun as obtained from helioseismology is applied. We obtain an estimate of the ratio of the two induction effects, C_alpha/C_Omega \\approx 10^-3, which we keep fixed in all models. We also include a one-cell meridional circulation pattern having a magnitude of 10-20 m/s near the surface and 1-2 m/s at the bottom of the convection zone. The model essentially represents a distributed turbulent dynamo, as the alpha-effect is nonzero throughout the convection zone, although it concentrates near the bottom of the convection zone obtaining a maximum around 30 degrees of latitude. Turbulent pumping of the mean fields is predominantly down- and equatorward. We find that, when all these effects are included in the model, it is possible to correctly reproduce many features of the solar activity cycle, namely the correct equatorward migration at low latitudes and the polar branch at high latitudes, and the observed negative sign of B_r B_phi. Although the activity clearly shifts towards the equator in comparison to previous models due to the combined action of the alpha-effect peaking at midlatitudes, meridional circulation and latitudinal pumping, most of the activity still occurs at too high latitudes (between 5-60 degrees). Other problems include the relatively narrow parameter space within which the preferred solution is dipolar (A0), and the somewhat too short cycle lengths of the solar-type solutions. The role of the surface shear layer is found to be important only in the case where the alpha-effect has an appreciable magnitude near the surface.

P. J. Käpylä; M. J. Korpi; I. Tuominen

2006-06-05T23:59:59.000Z

389

Impacts of Microphysical Scheme on Convective and Stratiform Characteristics in Two High Precipitation Squall Line Events  

SciTech Connect (OSTI)

This study investigates the impact of snow, graupel, and hail processes on the simulated squall lines over the Southern Great Plains in the United States. Weather Research and Forecasting (WRF) model is used to simulate two squall line events in May 2007, and the results are validated against radar and surface observations in Oklahoma. Several microphysics schemes are tested in this study, including WRF 5-Class Microphysics Scheme (WSM5), WRF 6-Class Microphysics Scheme (WSM6), Goddard Three Ice scheme (Goddard 3-ice) with graupel, Goddard Two Ice scheme (Goddard 2-ice), and Goddard 3-ice hail scheme. The simulated surface precipitation is sensitive to the microphysics scheme, and especially to whether graupel or hail category is included. All of the three ice (3-ice) schemes overestimated the total precipitation, within which WSM6 has the highest overestimation. Two ice (2-ice) schemes, missing a graupel/hail category, produced less total precipitation than 3-ice schemes. By applying a radar-based convective/stratiform partitioning algorithm, we find that by including the graupel/hail processes, there is an increase in areal coverage, precipitation intensity, updraft and downdraft intensity in convective region and a reduction of areal coverage and its precipitation intensity in stratiform region. For vertical structures, all the bulk schemes, especially 2-ice schemes, have the highest reflectivity located at upper levels (~8 km), which is unrealistic compared to observations. In addition, this study shows the radar-based convective/stratiform partitioning algorithm can reasonably identify WRF simulated precipitation, wind and microphysics fields in both convective and stratiform regions.

Wu, Di; Dong, Xiquan; Xi, Baike; Feng, Zhe; Kennedy, Aaron; Mullendore, Gretchen; Gilmore, Matthew; Tao, Wei-Kuo

2013-10-04T23:59:59.000Z

390

Electrodeposition of high Mo content Ni-Mo alloys under forced convection  

SciTech Connect (OSTI)

Bright, compact, adherent, metallic Ni-Mo alloys, containing over 48 wt % Mo have been electrodeposited from an aqueous solution. The Mo content, which is the highest achieved so far in induced codeposition of Ni-Mo, was determined by X-ray fluorescence spectroscopy. The absence of oxygen was verified by Auger electron spectroscopy. Electrodeposition experiments were performed on rotating cylinder electrodes and demonstrate that the Mo content of the alloy is strongly influenced by convective transport.

Podlaha, E.J.; Matlosz, M.; Landolt, D. (Ecole Polytechnique Federale de Lausanne, Lausanee (Switzerland). Dept. des materiaux)

1993-10-01T23:59:59.000Z

391

Antisymmetric polar modes of thermal convection in rotating fluid spherical shells at high Taylor numbers  

E-Print Network [OSTI]

of the liquid sodium ( = 0.01). For the first time, it is shown that at very high Taylor numbers the first numbers: 47.15.-x, 47.20.-k Electronic address: sanchez@fa.upc.edu Electronic address: marta@fa.upc by the properties of convection. The large-scale zonal winds observed in the surface of Jupiter at mid- and low

Sánchez, Juan

392

Non-Darcian forced convection in porous media with anisotropic dispersion  

SciTech Connect (OSTI)

Convective heat transfer in a particle packed tube is modeled in this paper. Axial and radial dispersion are both included in the governing equations. Results are compared with experimental data, and with previously developed models that did not include axial dispersion. It is shown that heat transfer in the thermally developing region is affected by axial dispersion when Peclet number is smaller than 10. Graphic results are provided to show the importance of axial dispersion for various Peclet numbers. 17 refs., 5 figs.

Adnani, P.; Catton, I.; Abdou, M.A. [Univ. of California, Los Angeles, CA (United States)

1995-05-01T23:59:59.000Z

393

Massive Variability Surveys from Venezuela  

E-Print Network [OSTI]

At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community.

Cesar Briceno

2003-04-03T23:59:59.000Z

394

Equatorial symmetry of Boussinesq convective solutions in a rotating spherical shell allowing rotation of the inner and outer spheres  

SciTech Connect (OSTI)

We investigate properties of convective solutions of the Boussinesq thermal convection in a moderately rotating spherical shell allowing the respective rotation of the inner and outer spheres due to the viscous torque of the fluid. The ratio of the inner and outer radii of the spheres, the Prandtl number, and the Taylor number are fixed to 0.4, 1, and 500{sup 2}, respectively. The Rayleigh number is varied from 2.6 × 10{sup 4} to 3.4 × 10{sup 4}. In this parameter range, the behaviours of obtained asymptotic convective solutions are almost similar to those in the system whose inner and outer spheres are restricted to rotate with the same constant angular velocity, although the difference is found in the transition process to chaotic solutions. The convective solution changes from an equatorially symmetric quasi-periodic one to an equatorially symmetric chaotic one, and further to an equatorially asymmetric chaotic one, as the Rayleigh number is increased. This is in contrast to the transition in the system whose inner and outer spheres are assumed to rotate with the same constant angular velocity, where the convective solution changes from an equatorially symmetric quasi-periodic one, to an equatorially asymmetric quasi-periodic one, and to equatorially asymmetric chaotic one. The inner sphere rotates in the retrograde direction on average in the parameter range; however, it sometimes undergoes the prograde rotation when the convective solution becomes chaotic.

Kimura, Keiji; Takehiro, Shin-ichi; Yamada, Michio [Research Institute for Mathematical Sciences, Kyoto University, Kyoto 606-8502 (Japan)

2014-08-15T23:59:59.000Z

395

Review of Probability Random Variable  

E-Print Network [OSTI]

at close 4) Height of wheel going over a rocky road #12;3 Random Variable Non-examples 1) `Heads' or `Tails' on coin 2) Red or Black ball from urn But we can make these into RV's Basic Idea ­ don't know · Temperature · Wheel height #12;5 Given Continuous RV X... What is the probability that X = x0 ? Oddity : P

Fowler, Mark

396

Chaotic mean wind in turbulent thermal convection and long-term correlations in solar activity  

E-Print Network [OSTI]

It is shown that correlation function of the mean wind velocity in a turbulent thermal convection (Rayleigh number $Ra \\sim 10^{11}$) exhibits exponential decay with a very long correlation time, while corresponding largest Lyapunov exponent is certainly positive. These results together with the reconstructed phase portrait indicate presence of a chaotic component in the examined mean wind. Telegraph approximation is also used to study relative contribution of the chaotic and stochastic components to the mean wind fluctuations and an equilibrium between these components has been studied. Since solar activity is based on the thermal convection processes, it is reasoned that the observed solar activity long-term correlations can be an imprint of the mean wind chaotic properties. In particular, correlation function of the daily sunspots number exhibits exponential decay with a very long correlation time and corresponding largest Lyapunov exponent is certainly positive, also relative contribution of the chaotic and stochastic components follows the same pattern as for the convection mean wind.

A. Bershadskii

2009-12-25T23:59:59.000Z

397

Microphysical Effects Determine Macrophysical Response for Aerosol Impacts on Deep Convective Clouds  

SciTech Connect (OSTI)

Deep convective clouds (DCCs) play a crucial role in the general circulation and energy and hydrological cycle of our climate system. Anthropogenic and natural aerosol particles can influence DCCs through changes in cloud properties, precipitation regimes, and radiation balance. Modeling studies have reported both invigoration and suppression of DCCs by aerosols, but none has fully quantified aerosol impacts on convection life cycle and radiative forcing. By conducting multiple month-long cloud-resolving simulations with spectral-bin cloud microphysics that capture the observed macro- and micro-physical properties of summer convective clouds in the tropics and mid-latitudes, this study provides the first comprehensive look at how aerosols affect cloud cover, cloud top height (CTH), and radiative forcing. Observations validate these simulation results. We find that microphysical aerosol effects contribute predominantly to increased cloud cover and CTH by inducing larger amount of smaller but longer lasting ice particles in the stratiform/anvils of DCCs with dynamical aerosol effects contributing at most ~ 1/4 of the total increase of cloud cover. The overall effect is a radiative warming in the atmosphere (3 to 5 W m-2) with strong surface cooling (-5 to -8 W m-2). Herein we clearly identified mechanisms more important than and additional to the invigoration effects hypothesized previously that explain the consistent signatures of increased cloud tops area and height by aerosols in DCCs revealed by observations.

Fan, Jiwen; Leung, Lai-Yung R.; Rosenfeld, Daniel; Chen, Qian; Li, Zhanqing; Zhang, Jinqiang; Yan, Hongru

2013-11-26T23:59:59.000Z

398

Improvements of the Variable Thermal Resistance  

E-Print Network [OSTI]

A flat mounting unit with electronically variable thermal resistance [1] has been presented in the last year [2]. The design was based on a Peltier cell and the appropriate control electronics and software. The device is devoted especially to the thermal characterization of packages, e.g. in dual cold plate arrangements. Although this design meets the requirements of the static measurement we are intended to improve its parameters as the settling time and dynamic thermal impedance and the range of realized thermal resistance. The new design applies the heat flux sensor developed by our team as well [3], making easier the control of the device. This development allows even the realization of negative thermal resistances.

Székely, V; Kollar, E

2008-01-01T23:59:59.000Z

399

Improvements of the Variable Thermal Resistance  

E-Print Network [OSTI]

A flat mounting unit with electronically variable thermal resistance [1] has been presented in the last year [2]. The design was based on a Peltier cell and the appropriate control electronics and software. The device is devoted especially to the thermal characterization of packages, e.g. in dual cold plate arrangements. Although this design meets the requirements of the static measurement we are intended to improve its parameters as the settling time and dynamic thermal impedance and the range of realized thermal resistance. The new design applies the heat flux sensor developed by our team as well [3], making easier the control of the device. This development allows even the realization of negative thermal resistances.

V. Szekely; S. Torok; E. Kollar

2008-01-07T23:59:59.000Z

400

Effective Theories of Coupled Classical and Quantum Variables  

E-Print Network [OSTI]

We address the issue of coupling variables which are essentially classical to variables that are quantum. Two approaches are discussed. In the first (based on collaborative work with L.Di\\'osi), continuous quantum measurement theory is used to construct a phenomenological description of the interaction of a quasiclassical variable $X$ with a quantum variable $x$, where the quasiclassical nature of $X$ is assumed to have come about as a result of decoherence. The state of the quantum subsystem evolves according to the stochastic non-linear Schr\\"odinger equation of a continuously measured system, and the classical system couples to a stochastic c-number $\\x (t)$ representing the imprecisely measured value of $x$. The theory gives intuitively sensible results even when the quantum system starts out in a superposition of well-separated localized states. The second approach involves a derivation of an effective theory from the underlying quantum theory of the combined quasiclassical--quantum system, and uses the decoherent histories approach to quantum theory.

J. J. Halliwell

1998-08-26T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Method and system to estimate variables in an integrated gasification combined cycle (IGCC) plant  

DOE Patents [OSTI]

System and method to estimate variables in an integrated gasification combined cycle (IGCC) plant are provided. The system includes a sensor suite to measure respective plant input and output variables. An extended Kalman filter (EKF) receives sensed plant input variables and includes a dynamic model to generate a plurality of plant state estimates and a covariance matrix for the state estimates. A preemptive-constraining processor is configured to preemptively constrain the state estimates and covariance matrix to be free of constraint violations. A measurement-correction processor may be configured to correct constrained state estimates and a constrained covariance matrix based on processing of sensed plant output variables. The measurement-correction processor is coupled to update the dynamic model with corrected state estimates and a corrected covariance matrix. The updated dynamic model may be configured to estimate values for at least one plant variable not originally sensed by the sensor suite.

Kumar, Aditya; Shi, Ruijie; Dokucu, Mustafa

2013-09-17T23:59:59.000Z

402

Variable flexure-based fluid filter  

DOE Patents [OSTI]

An apparatus and method for filtering particles from a fluid comprises a fluid inlet, a fluid outlet, a variable size passage between the fluid inlet and the fluid outlet, and means for adjusting the size of the variable size passage for filtering the particles from the fluid. An inlet fluid flow stream is introduced to a fixture with a variable size passage. The size of the variable size passage is set so that the fluid passes through the variable size passage but the particles do not pass through the variable size passage.

Brown, Steve B.; Colston Jr., Billy W.; Marshall, Graham; Wolcott, Duane

2007-03-13T23:59:59.000Z

403

Variability in the Southerly Flow into the Eastern Pacific ITCZ* SIMON P. DE SZOEKE  

E-Print Network [OSTI]

and latent heat release in deep convective towers form the vigor- ous upward branch of the Hadley circulation, which transmits surface solar heating throughout the tropo- sphere. The distribution of deep convection

Bretherton, Chris

404

Experimental and CFD Analysis of Advanced Convective Cooling Systems  

SciTech Connect (OSTI)

The objective of this project is to study the fundamental physical phenomena in the reactor cavity cooling system (RCCS) of very high-temperature reactors (VHTRs). One of the primary design objectives is to assure that RCCS acts as an ultimate heat sink capable of maintaining thermal integrity of the fuel, vessel, and equipment within the reactor cavity for the entire spectrum of postulated accident scenarios. Since construction of full-scale experimental test facilities to study these phenomena is impractical, it is logical to expect that computational fluid dynamics (CFD) simulations will play a key role in the RCCS design process. An important question then arises: To what extent are conventional CFD codes able to accurately capture the most important flow phenomena, and how can they be modified to improve their quantitative predictions? Researchers are working to tackle this problem in two ways. First, in the experimental phase, the research team plans to design and construct an innovative platform that will provide a standard test setting for validating CFD codes proposed for the RCCS design. This capability will significantly advance the state of knowledge in both liquid-cooled and gas-cooled (e.g., sodium fast reactor) reactor technology. This work will also extend flow measurements to micro-scale levels not obtainable in large-scale test facilities, thereby revealing previously undetectable phenomena that will complement the existing infrastructure. Second, in the computational phase of this work, numerical simulation of the flow and temperature profiles will be performed using advanced turbulence models to simulate the complex conditions of flows in critical zones of the cavity. These models will be validated and verified so that they can be implemented into commercially available CFD codes. Ultimately, the results of these validation studies can then be used to enable a more accurate design and safety evaluation of systems in actual nuclear power applications (both during normal operation and accident scenarios).

Yassin A. Hassan; Victor M. Ugaz

2012-06-27T23:59:59.000Z

405

Principal Components Instrumental Variable Estimation  

E-Print Network [OSTI]

of the main results are displayed in two appendices. 2 Econometric Framework Consider the simultaneous equations model y = X? + u and X = Z?+ V , (1) 1 An advantage of such general structure is that the ‘large-sample’ condition used in previous studies Kn/ p n... ? 0, where Kn is the number of instruments and n is the sample size, is not required in our asymptotic approximations. 4 where y is the n × 1 vector containing n observations of the dependent variable; X is the n × G matrix with observations...

Winkelried, Diego; Smith, Richard J.

2011-01-31T23:59:59.000Z

406

Variable Average Absolute Percent Differences  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism inS-4500II FieldVacancy-InducedCloudPoissonVampire Power1 -Variable

407

Variable Mass Theories of Gravity  

E-Print Network [OSTI]

Several attempts to construct theories of gravity with variable mass are considered. The theoretical impacts of allowing the rest mass to vary with respect to time or an appropriate curve parameter are examined in the framework of Newtonian and Einsteinian gravity theories. In further steps, scalar-tensor theories are examined with respect to their relation to the variation of the mass and in an ultimate step, an additional coordinate is introduced and its possible relation to the mass is examined, yielding a five dimensional space-time-matter theory.

M. Leclerc

2002-12-03T23:59:59.000Z

408

Interannual variability in tropospheric nitrous oxide  

E-Print Network [OSTI]

Observations of tropospheric N2O mixing ratio show significant variability on interannual timescales (0.2?ppb, 1 standard deviation). We found that interannual variability in N2O is weakly correlated with that in CFC-12 ...

Thompson, R. L.

409

Utility Variable Generation Integration Group Fall Technical...  

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

Technical Workshop Utility Variable Generation Integration Group Fall Technical Workshop October 15, 2014 9:00AM CDT to October 17, 2014 3:00PM CDT The Utility Variable Generation...

410

Mon. Not. R. Astron. Soc. 000, 000000 (0000) Printed 31 July 2012 (MN LATEX style file v2.2) Data assimilation for stratified convection  

E-Print Network [OSTI]

assimilation for stratified convection Andreas Svedin1 , Milena C. Cu´ellar2 and Axel Brandenburg3,4 1Astronomy

Brandenburg, Axel

411

Strategies for Mitigating the Reduction in Economic Value of Variable Generation with Increasing Penetration Levels  

SciTech Connect (OSTI)

In this report, we evaluate individual options that have the potential to stem the decline in the marginal value of variable generation (VG) with increasing penetration levels. We focus only on the effectiveness of mitigation measures for wind and PV.

Mills, Andrew; Wiser, Ryan

2014-03-03T23:59:59.000Z

412

The Use of Variable Speed Drives to Retrofit Hydraulic Injection Molding Machines  

E-Print Network [OSTI]

Research Institute, Palo Alto, California. 8.) Remley, Carl H. (1993) "Measured performance of variable speed drives on injection molding hydraulic pumps." Energy Management Consulting and Equipment, Inc., North Attleboro, Massachusetts'. 9.) Rosato...

Ambs, L.; Frerker, M. M.

413

Utilizing CLASIC observations and multiscale models to study the impact of improved Land surface representation on modeling cloud- convection  

SciTech Connect (OSTI)

The CLASIC experiment was conducted over the US southern great plains (SGP) in June 2007 with an objective to lead an enhanced understanding of the cumulus convection particularly as it relates to land surface conditions. This project was design to help assist with understanding the overall improvement of land atmosphere convection initiation representation of which is important for global and regional models. The study helped address one of the critical documented deficiency in the models central to the ARM objectives for cumulus convection initiation and particularly under summer time conditions. This project was guided by the scientific question building on the CLASIC theme questions: What is the effect of improved land surface representation on the ability of coupled models to simulate cumulus and convection initiation? The focus was on the US Southern Great Plains region. Since the CLASIC period was anomalously wet the strategy has been to use other periods and domains to develop the comparative assessment for the CLASIC data period, and to understand the mechanisms of the anomalous wet conditions on the tropical systems and convection over land. The data periods include the IHOP 2002 field experiment that was over roughly same domain as the CLASIC in the SGP, and some of the DOE funded Ameriflux datasets.

Niyogi, Devdutta S. [Purdue

2013-06-07T23:59:59.000Z

414

Variable ratio regenerative braking device  

DOE Patents [OSTI]

Disclosed is a regenerative braking device (10) for an automotive vehicle. The device includes an energy storage assembly (12) having a plurality of rubber rollers (26, 28) mounted for rotation between an input shaft (36) and an output shaft (42), clutches (38, 46) and brakes (40, 48) associated with each shaft, and a continuously variable transmission (22) connectable to a vehicle drivetrain and to the input and output shafts by the respective clutches. The rubber rollers are torsionally stressed to accumulate energy from the vehicle when the input shaft is clutched to the transmission while the brake on the output shaft is applied, and are torsionally relaxed to deliver energy to the vehicle when the output shaft is clutched to the transmission while the brake on the input shaft is applied. The transmission ratio is varied to control the rate of energy accumulation and delivery for a given rotational speed of the vehicle drivetrain.

Hoppie, Lyle O. (Birmingham, MI)

1981-12-15T23:59:59.000Z

415

Variable delivery, fixed displacement pump  

DOE Patents [OSTI]

A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

Sommars, Mark F. (Sparland, IL)

2001-01-01T23:59:59.000Z

416

Continuously variable focal length lens  

DOE Patents [OSTI]

A material preferably in crystal form having a low atomic number such as beryllium (Z=4) provides for the focusing of x-rays in a continuously variable manner. The material is provided with plural spaced curvilinear, optically matched slots and/or recesses through which an x-ray beam is directed. The focal length of the material may be decreased or increased by increasing or decreasing, respectively, the number of slots (or recesses) through which the x-ray beam is directed, while fine tuning of the focal length is accomplished by rotation of the material so as to change the path length of the x-ray beam through the aligned cylindrical slows. X-ray analysis of a fixed point in a solid material may be performed by scanning the energy of the x-ray beam while rotating the material to maintain the beam's focal point at a fixed point in the specimen undergoing analysis.

Adams, Bernhard W; Chollet, Matthieu C

2013-12-17T23:59:59.000Z

417

Variable residence time vortex combustor  

DOE Patents [OSTI]

A variable residence time vortex combustor including a primary combustion chamber for containing a combustion vortex, and a plurality of louvres peripherally disposed about the primary combustion chamber and longitudinally distributed along its primary axis. The louvres are inclined to impel air about the primary combustion chamber to cool its interior surfaces and to impel air inwardly to assist in driving the combustion vortex in a first rotational direction and to feed combustion in the primary combustion chamber. The vortex combustor also includes a second combustion chamber having a secondary zone and a narrowed waist region in the primary combustion chamber interconnecting the output of the primary combustion chamber with the secondary zone for passing only lower density particles and trapping higher density particles in the combustion vortex in the primary combustion chamber for substantial combustion.

Melconian, Jerry O. (76 Beaver Rd., Reading, MA 01867)

1987-01-01T23:59:59.000Z

418

Sources, sinks and holes in a one-dimensional traveling wave convection experiment  

E-Print Network [OSTI]

We study dynamical behavior of local structures, such as sources and holes, in traveling wave patterns in a very long (2 m) heated wire convection experiment. The {\\em sources} undergo a transition from stable coherent behavior to erratic behavior when the driving parameter $\\epsilon$ is {\\em decreased}. This transition, as well as the scaling of the average source width in the erratic regime, are both qualitatively and quantitatively in accord with earlier theoretical predictions. We also present new results for the {\\em holes} sent out by the erratic sources.

Luc Pastur; Mark-Tiele Westra; Daniel Snouck; Willem van de Water; Martin van Hecke; Cornelis Storm; Wim van Saarloos

2003-01-29T23:59:59.000Z

419

Convection in X-ray Bursts Michael Zingale Stony Brook University  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationCleanCommunity2Workshops01ControllingControls on SolubleConvection in

420

Liquid Salts as Media for Process Heat Transfer from VHTR's: Forced Convective Channel Flow Thermal Hydraulics, Materials, and Coating  

SciTech Connect (OSTI)

The goal of this NERI project was to perform research on high temperature fluoride and chloride molten salts towards the long-term goal of using these salts for transferring process heat from high temperature nuclear reactor to operation of hydrogen production and chemical plants. Specifically, the research focuses on corrosion of materials in molten salts, which continues to be one of the most significant challenges in molten salts systems. Based on the earlier work performed at ORNL on salt properties for heat transfer applications, a eutectic fluoride salt FLiNaK (46.5% LiF-11.5%NaF-42.0%KF, mol.%) and a eutectic chloride salt (32%MgCl2-68%KCl, mole %) were selected for this study. Several high temperature candidate Fe-Ni-Cr and Ni-Cr alloys: Hastelloy-N, Hastelloy-X, Haynes-230, Inconel-617, and Incoloy-800H, were exposed to molten FLiNaK with the goal of understanding corrosion mechanisms and ranking these alloys for their suitability for molten fluoride salt heat exchanger and thermal storage applications. The tests were performed at 850��������C for 500 h in sealed graphite crucibles under an argon cover gas. Corrosion was noted to occur predominantly from dealloying of Cr from the alloys, an effect that was particularly pronounced at the grain boundaries Alloy weight-loss due to molten fluoride salt exposure correlated with the initial Cr-content of the alloys, and was consistent with the Cr-content measured in the salts after corrosion tests. The alloys���¢�������� weight-loss was also found to correlate to the concentration of carbon present for the nominally 20% Cr containing alloys, due to the formation of chromium carbide phases at the grain boundaries. Experiments involving molten salt exposures of Incoloy-800H in Incoloy-800H crucibles under an argon cover gas showed a significantly lower corrosion for this alloy than when tested in a graphite crucible. Graphite significantly accelerated alloy corrosion due to the reduction of Cr from solution by graphite and formation on Cr-carbide on the graphite surface. Ni-electroplating dramatically reduced corrosion of alloys, although some diffusion of Fe and Cr were observed occur through the Ni plating. A pyrolytic carbon and SiC (PyC/SiC) CVD coating was also investigated and found to be effective in mitigating corrosion. The KCl-MgCl2 molten salt was less corrosive than FLiNaK fluoride salts for corrosion tests performed at 850oC. Cr dissolution in the molten chloride salt was still observed and consequently Ni-201 and Hastelloy N exhibited the least depth of attack. Grain-boundary engineering (GBE) of Incoloy 800H improved the corrosion resistance (as measured by weight loss and maximum depth of attack) by nearly 50% as compared to the as-received Incoloy 800H sample. Because Cr dissolution is an important mechanism of corrosion, molten salt electrochemistry experiments were initiated. These experiments were performed using anodic stripping voltammetry (ASV). Using this technique, the reduction potential of Cr was determined against a Pt quasi-reference electrode as well as against a Ni(II)-Ni reference electrode in molten FLiNaK at 650 oC. The integrated current increased linearly with Cr-content in the salt, providing for a direct assessment of the Cr concentration in a given salt of unknown Cr concentration. To study heat transfer mechanisms in these molten salts over the forced and mixed convection regimes, a forced convective loop was constructed to measure heat transfer coefficients, friction factors and corrosion rates in different diameter tubes in a vertical up flow configuration in the laminar flow regime. Equipment and instrumentation for the forced convective loop was designed, constructed, and tested. These include a high temperature centrifugal pump, mass flow meter, and differential pressure sensing capabilities to an uncertainty of < 2 Pa. The heat transfer coefficient for the KCl-MgCl2 salt was measured in t

Kumar Sridharan; Mark Anderson; Todd Allen; Michael Corradini

2012-01-30T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Evidence for Two Distinct Morphological Classes of Gamma-Ray Bursts from their Short Timescale Variability  

E-Print Network [OSTI]

We have analyzed the 241 bursts for which peak counts $\\C$ exist in the publicly available Burst and Transient Source Experiment (BATSE) catalog. Introducing peak counts in 1024 ms as a measure of burst brightness $\\B$ and the ratio of peak counts in 64 and 1024 ms as a measure of short timescale variability $\\V$, we find a statistically significant correlation between the brightness and the short timescale variability of \\g-ray bursts. The bursts which are smoother on short timescales are both faint and bright, while the bursts which are variable on short timescales are faint only, suggesting the existence of two distinct morphological classes of bursts.

D. Q. Lamb; C. Graziani; I. A. Smith

1993-06-15T23:59:59.000Z

422

Atomic filtering for hybrid continuous-variable/discrete-variable quantum optics  

E-Print Network [OSTI]

We demonstrate atomic filtering of frequency-degenerate photon pairs from a sub-threshold optical parametric oscillator (OPO). The filter, a modified Faraday anomalous dispersion optical filter (FADOF), achieves 70% peak transmission simultaneous with 57 dB out-of-band rejection and a 445 MHz transmission bandwidth. When applied to the OPO output, only the degenerate mode, containing one-mode squeezed vacuum, falls in the filter pass-band; all other modes are strongly suppressed. The high transmission preserves non-classical continuous-variable features, e.g. squeezing or non-gaussianity, while the high spectral purity allows reliable discrete-variable detection and heralding. Correlation and atomic absorption measurements indicate a spectral purity of 96% for the individual photons, and 98% for the photon pairs. These capabilities will enable generation of atom-resonant hybrid states, e.g. "Schr\\"odinger kittens" obtained by photon subtraction from squeezed vacuum, making these exotic states available for quantum networking and atomic quantum metrology applications.

Joanna A. Zieli?ska; Federica A. Beduini; Vito Giovanni Lucivero; Morgan W. Mitchell

2014-09-04T23:59:59.000Z

423

Convective heat transfer on leeward building walls in an urban environment: Measurements in an outdoor scale model  

E-Print Network [OSTI]

surface, Proc. 5 th Int. Heat Transfer Conf. 3 (1974) 129-a vertical plate, J. Heat Transfer 109(1) [13] K. Patel,Experimental study of heat transfer in turbulent flows over

Nottrott, A.; Onomura, S.; Inagaki, A.; Kanda, M.; Kleissl, J.

2011-01-01T23:59:59.000Z

424

Convective heat transfer on leeward building walls in an urban environment: Measurements in an outdoor scale model  

E-Print Network [OSTI]

layer wind speed (height 2H) and the vertical velocity nearthe horizontal wind speed at 2H and the average verticalvertical error bars indicate the magnitude of the UC wind speed

Nottrott, A.; Onomura, S.; Inagaki, A.; Kanda, M.; Kleissl, J.

2011-01-01T23:59:59.000Z

425

Convection Triggering  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationCleanCommunity2Workshops01ControllingControls on Soluble PuQuantifying

426

HCCI in a Variable Compression Ratio Engine: Effects of Engine...  

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

Fuels Practical Full Time HCCI Operation Will Require Specific HCCI Fuel Low Octane gasoline Experimental Variables Experimental Variables Engine Variables Intake Manifold...

427

CALIBRATING CONVECTIVE PROPERTIES OF SOLAR-LIKE STARS IN THE KEPLER FIELD OF VIEW  

SciTech Connect (OSTI)

Stellar models generally use simple parameterizations to treat convection. The most widely used parameterization is the so-called mixing-length theory where the convective eddy sizes are described using a single number, {alpha}, the mixing-length parameter. This is a free parameter, and the general practice is to calibrate {alpha} using the known properties of the Sun and apply that to all stars. Using data from NASA's Kepler mission we show that using the solar-calibrated {alpha} is not always appropriate, and that in many cases it would lead to estimates of initial helium abundances that are lower than the primordial helium abundance. Kepler data allow us to calibrate {alpha} for many other stars and we show that for the sample of stars we have studied, the mixing-length parameter is generally lower than the solar value. We studied the correlation between {alpha} and stellar properties, and we find that {alpha} increases with metallicity. We therefore conclude that results obtained by fitting stellar models or by using population-synthesis models constructed with solar values of {alpha} are likely to have large systematic errors. Our results also confirm theoretical expectations that the mixing-length parameter should vary with stellar properties.

Bonaca, Ana; Tanner, Joel D.; Basu, Sarbani [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Chaplin, William J.; Metcalfe, Travis S.; Christensen-Dalsgaard, Jorgen; Garcia, Rafael A.; Mathur, Savita [Kavli Institute for Theoretical Physics, Kohn Hall, University of California, Santa Barbara, CA 93106 (United States); Monteiro, Mario J. P. F. G.; Campante, Tiago L. [Centro de Astrofisica and Faculdade de Ciencias, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Ballot, Jerome [CNRS, Institut de Recherche en Astrophysique et Planetologie, 14 avenue Edouard Belin, F-31400 Toulouse (France); Bedding, Timothy R.; Corsaro, Enrico [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Bonanno, Alfio [INAF-Osservatorio Astrofisico di Catania, Via S.Sofia 78, I-95123 Catania (Italy); Broomhall, Anne-Marie; Elsworth, Yvonne [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Bruntt, Hans; Karoff, Christoffer; Kjeldsen, Hans [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Hekker, Saskia, E-mail: ana.bonaca@yale.edu, E-mail: sarbani.basu@yale.edu, E-mail: joel.tanner@yale.edu [Astronomical Institute Anton Pannekoek, University of Amsterdam, Science Park 904, 1098-XH Amsterdam (Netherlands); and others

2012-08-10T23:59:59.000Z

428

Natural convection in horizontal porous layers with localized heating from below  

SciTech Connect (OSTI)

Convective flow of fluid through saturated porous media heated from below is of considerable interest, and has been extensively studied. Most of these studies are concerned with either infinite horizontal porous layers or rectangular (or cylindrical) porous cavities with adiabatic vertical walls. A related problem of practical importance occurs when only a portion of the bottom surface is heated and the rest of it is either adiabatic or isothermally cooled. This situation is encountered in several geothermal areas which consists of troughs of volcanic debris contained by walls of nonfragmented ignimbrite. Thus, the model region considered is a locally heated long trough of isotropic porous medium confined by impermeable and insulating surroundings. Also, the recent motivation to study this problem has come from the efforts to identify a geologic repository for nuclear waste disposal. The purpose of the present work is to consider the effects of aspect ratio and Rayleigh number on free convection heat transfer from an isothermal heat source centrally located on the bottom surface of a horizontal porous cavity.

Prasad, V. (Columbia Univ., New York, NY (United States)); Kulacki, F.A. (Univ. of Delaware, Newark (United States))

1987-08-01T23:59:59.000Z

429

The effect of nuclear reaction rates and convective mixing on the evolution of a 6M{sub ?} star  

SciTech Connect (OSTI)

We present the evolution of a 6M{sub ?} star, of solar-like initial metallicity, and investigate the effects of key nuclear reaction rates, as well as the treatment of the convective mixing on its evolution along the Cepheid instability strip. In particular, we study the effect of recent estimates of the {sup 14}N(p,?){sup 15}O reaction on the formation and extension of the blue loop during core helium burning. We also investigate the effects induced on this blue loop by the adoption of non-standard convective mixing prescriptions, as well as the implications of modifying the Mixing Length Theory.

Halabi, Ghina M., E-mail: gfm01@aub.edu.lb [American University of Beirut, Department of Physics, P.O. Box 11-0236, Riad El-Solh, Beirut (Lebanon)

2014-05-09T23:59:59.000Z

430

Evolution of cloud-to-ground lightning characteristics within the convective region of a midlatitude squall line  

E-Print Network [OSTI]

region, descending through an area of mesoscale descent, and reaching the rear of the convective line near the surface. Though not explicitly shown in Fig. 7, a transition zone of weak echo between the convective and stratiform regions has also been...-levels define the grid points of the template. The scheme focuses on inclusion of the developing mid-level cells in the forward part of the squall line and exclusion of the transition zone at lower levels in the rearward portion of the line. The templates...

Billingsley, David Brian

2012-06-07T23:59:59.000Z

431

Seasonal Variability in Anthropogenic Halocarbon  

E-Print Network [OSTI]

ozone depleting potential and as hazards to human health, they are also of concern due to their positive banned by the Montreal Protocol with a minimal number of exceptions for critical purposes in a few-12). For example, studies measuring halocarbons in off-gas from municipal solid waste (MSW) landfills report

Cohen, Ronald C.

432

Simulation of radiometric and attenuation measurements along Earth-satellite links in the 10-to 50-GHz band  

E-Print Network [OSTI]

to modeling a convective rain cell of cylindrical shape, characterized by spherical raindrops having-based radiometric measurements together with the frequency scaling factors for cumuliform clouds in the 10- to 50. As a compromise, semiempirical methods have also been proposed by using both experimental data and theoretical

Marzano, Frank Silvio

433

HERSCHEL OBSERVATIONS OF CATACLYSMIC VARIABLES  

SciTech Connect (OSTI)

We have used the PACS instrument on the Herschel Space Observatory to observe eight cataclysmic variables at 70 and 160 {mu}m. Of these eight objects, only AM Her was detected. We have combined the Herschel results with ground-based, Spitzer, and WISE observations to construct spectral energy distributions for all of the targets. For the two dwarf novae in the sample, SS Cyg and U Gem, we find that their infrared luminosities are completely dominated by their secondary stars. For the two highly magnetic 'polars' in our survey, AM Her and EF Eri, we find that their mid-infrared excesses, previously attributed to circumbinary dust emission, can be fully explained by cyclotron emission. The WISE light curves for both sources show large, orbitally modulated variations that are identically phased to their near-IR light curves. We propose that significant emission from the lowest cyclotron harmonics (n {<=} 3) is present in EF Eri and AM Her. Previously, such emission would have been presumed to be optically thick, and not provide significant orbitally modulated flux. This suggests that the accretion onto polars is more complicated than assumed in the simple models developed for these two sources. We develop a model for the near-/mid-IR light curves for WZ Sge with an L2 donor star that shows that the ellipsoidal variations from its secondary star are detected. We conclude that none of the targets surveyed have dusty circumbinary disks.

Harrison, Thomas E.; Hamilton, Ryan T. [Department of Astronomy, New Mexico State University, Box 30001, MSC 4500, Las Cruces, NM 88003-8001 (United States); Tappert, Claus [Departamento de Fisica y Astronomia, Universidad de Valparaiso, Avda. Gran Bretana 1111, Valparaiso (Chile); Hoffman, Douglas I. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Campbell, Ryan K., E-mail: tharriso@nmsu.edu, E-mail: rthamilt@nmsu.edu, E-mail: claus.tappert@uv.cl, E-mail: dhoffman@ipac.caltech.edu, E-mail: Ryan.Campbell@humobldt.edu [Department of Physics and Astronomy, Humboldt State University, 1 Harpst St., Arcata, CA 95521 (United States)

2013-01-01T23:59:59.000Z

434

Eccentric crank variable compression ratio mechanism  

DOE Patents [OSTI]

A variable compression ratio mechanism for an internal combustion engine that has an engine block and a crankshaft is disclosed. The variable compression ratio mechanism has a plurality of eccentric disks configured to support the crankshaft. Each of the plurality of eccentric disks has at least one cylindrical portion annularly surrounded by the engine block. The variable compression ratio mechanism also has at least one actuator configured to rotate the plurality of eccentric disks.

Lawrence, Keith Edward (Kobe, JP); Moser, William Elliott (Peoria, IL); Roozenboom, Stephan Donald (Washington, IL); Knox, Kevin Jay (Peoria, IL)

2008-05-13T23:59:59.000Z

435

Variable-Period Undulators For Synchrotron Radiation  

DOE Patents [OSTI]

A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high-energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

Shenoy, Gopal (Naperville, IL); Lewellen, John (Plainfield, IL); Shu, Deming (Darien, IL); Vinokurov, Nikolai (Novosibirsk, RU)

2005-02-22T23:59:59.000Z

436

Variable-Period Undulators for Synchrotron Radiation  

SciTech Connect (OSTI)

A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

Shenoy, Gopal; Lewellen, John; Shu, Deming; Vinokurov, Nikolai

2005-02-22T23:59:59.000Z

437

Multivector Functions of a Real Variable  

E-Print Network [OSTI]

This paper is an introduction to the theory of multivector functions of a real variable. The notions of limit, continuity and derivative for these objects are given. The theory of multivector functions of a real variable, even being similar to the usual theory of vector functions of a real variable, has some subtle issues which make its presentation worhtwhile.We refer in particular to the derivative rules involving exterior and Clifford products, and also to the rule for derivation of a composition of an ordinary scalar function with a multivector function of a real variable.

A. M. Moya; V. V. Fernández; W. A. Rodrigues Jr

2002-12-17T23:59:59.000Z

438

Hybrid Bayesian Networks with Linear Deterministic Variables  

E-Print Network [OSTI]

Conference (UAI-05), 2005, AUAI Press, Arlington, VA. 136 Y X Z Figure 2: A Bayesian Network Representation of the Mixed Distribution for X. this example, Y is a discrete variable with state space ? Y = {1,2,3}, Z is a real-valued variable, and X is a... conditionally deterministic variable whose condi- tional distribution is described as follows: X |{y,z} = y if y =1,2 and X |{y,z} = z if y =3. Potentials of the type described above are used in this paper to represent distributions of variables in hy- brid...

Cobb, Barry R.; Shenoy, Prakash P.

2005-07-01T23:59:59.000Z

439

Simulating solar power plant variability : a review of current methods.  

SciTech Connect (OSTI)

It is important to be able to accurately simulate the variability of solar PV power plants for grid integration studies. We aim to inform integration studies of the ease of implementation and application-specific accuracy of current PV power plant output simulation methods. This report reviews methods for producing simulated high-resolution (sub-hour or even sub-minute) PV power plant output profiles for variability studies and describes their implementation. Two steps are involved in the simulations: estimation of average irradiance over the footprint of a PV plant and conversion of average irradiance to plant power output. Six models are described for simulating plant-average irradiance based on inputs of ground-measured irradiance, satellite-derived irradiance, or proxy plant measurements. The steps for converting plant-average irradiance to plant power output are detailed to understand the contributions to plant variability. A forthcoming report will quantify the accuracy of each method using application-specific validation metrics.

Lave, Matthew; Ellis, Abraham [Sandia National Laboratories, Albuquerque, NM; Stein, Joshua S. [Sandia National Laboratories, Albuquerque, NM

2013-06-01T23:59:59.000Z

440

Perturbation Growth at the Convective Scale G. Leoncini, R. S. Plant, S. L. Gray and P. A. Clark  

E-Print Network [OSTI]

Perturbation Growth at the Convective Scale G. Leoncini, R. S. Plant, S. L. Gray and P. A. Clark. Improvements in computational power mean that operational weather prediction models can now be run (during the entire simulation) of the perturbations. Diagnostics included root mean square precipitation

Plant, Robert

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Low-level convergence and its role in convective intensity and frequency over the Houston lightning and rainfall anomaly  

E-Print Network [OSTI]

of the urban heat island (UHI) and the sea-breeze, as a source of low-level convergence leading to enhanced convection over Houston, was examined. Hourly average dual-Doppler wind and convergence maps were created on 1 X 1 km grids for an eleven-week period...

McNear, Veronica Ann

2007-09-17T23:59:59.000Z

442

Convective Snowbands Downstream of the Rocky Mountains in an Environment with Conditional, Dry Symmetric, and Inertial Instabilities  

E-Print Network [OSTI]

Convective Snowbands Downstream of the Rocky Mountains in an Environment with Conditional, Dry quickly equatorward. The bands occurred downstream of complex terrain on the anticyclonic-shear side banners downstream of mountains, and in association with frontogenetical ascent along two baroclinic zones

Schumacher, Russ

443

Convective instability of a boundary layer with temperature-and strain-rate-dependent viscosity in terms of `available buoyancy'  

E-Print Network [OSTI]

be approximately proportional to the integral over the depth of the lithosphere of the 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

Conrad, Clint

444

Magnetic Inhibition of Convection and the Fundamental Properties of Low-Mass Stars. I. Stars with a Radiative Core  

E-Print Network [OSTI]

Magnetic fields are hypothesized to inflate the radii of low-mass stars---defined as less massive than 0.8 solar masses---in detached eclipsing binaries (DEBs). We investigate this hypothesis using the recently introduced magnetic Dartmouth stellar evolution code. In particular, we focus on stars thought to have a radiative core and convective outer envelope by studying in detail three individual DEBs: UV Psc, YY Gem, and CU Cnc. The results suggest that the stabilization of thermal convection by a magnetic field is a plausible explanation for the observed model-radius discrepancies. However, surface magnetic field strengths required by the models are significantly stronger than those estimated from the observed coronal X-ray emission. Agreement between model predicted surface magnetic field strengths and those inferred from X-ray observations can be found by assuming that the magnetic field sources its energy from convection. This approach makes the transport of heat by convection less efficient and is akin ...

Feiden, Gregory A

2013-01-01T23:59:59.000Z

445

October 1986 R. H. Johnson 721 Lower-Tropospheric Warming and Drying in Tropical Mesoscale Convective Systems  

E-Print Network [OSTI]

October 1986 R. H. Johnson 721 Lower-Tropospheric Warming and Drying in Tropical Mesoscale Convective Systems: Implications for the Problem of Cumulus Parameterization By Richard H. Johnson Department beneath the stratiform com- ponents of these systems (Houze, 1977; Zipser, 1977; Johnson and Kriete, 1982

Johnson, Richard H.

446

Turbine vanes experience high convective surface heat transfer as a consequence of the turbulent flow exiting the combustor. Before im-  

E-Print Network [OSTI]

1 Abstract Turbine vanes experience high convective surface heat transfer as a consequence region of the passage reacts as it passes between two adjacent turbine vanes. In this study, a scaled-up turbine vane geometry was used in a low-speed wind tunnel simulation. The test section included a cen

Thole, Karen A.

447

Clean Energy? Can Do! ANZSES 2006 1 of 9 A New Correlation for Predicting the Free Convection Loss from  

E-Print Network [OSTI]

be determined relatively easily by standardised methods given in a heat transfer literature. On the other hand-mail: sawat.paitoonsurikarn@anu.edu.au Abstract The study of free convection loss from an open-cavity receiver An open-cavity type receiver is widely used in solar paraboloidal dish applications, eg

448

ccsd-00003870,version1-11Jan2005 Importance of convection in the compaction mechanisms of anisotropic granular media  

E-Print Network [OSTI]

of the vortices and relate them to granular convection. Our results demonstrate the importance of compression of a glass cylinder of diameter D 10 cm filled with 600 g of grains (corre- sponding to a height of roughly) by vertical taps. Each tap is created by one entire period of sine wave at a fixed frequency f = 30 Hz

Paris-Sud XI, Université de

449

Solar Dynamics Observatory/ Extreme Ultraviolet Variability Experiment  

E-Print Network [OSTI]

Solar Dynamics Observatory/ EVE Extreme Ultraviolet Variability Experiment Frequently Asked and model solar extreme ultraviolet irradiance variations due to solar flares, solar rotation, and solar and structure of the Sun. What is solar variability? Solar radiation varies on all time scales ranging from

Mojzsis, Stephen J.

450

Variable Speed Pumping for Level Control  

E-Print Network [OSTI]

The purpose of this paper is to describe an application of variable speed pumping to level control of an industrial process. Topics include a comparison of the process using control valves with a variable speed system, an energy savings and cost...

Vasel, M.

1982-01-01T23:59:59.000Z

451

Practical evaluation of action-angle variables  

SciTech Connect (OSTI)

A practical method is described for establishing action-angle variables for a Hamiltonian system. That is, a given nearly integrable Hamiltonian is divided into an exactly integrable system plus a perturbation in action-angle form. The transformation of variables, which is carried out using a few short trajectory integrations, permits a rapid determination of trajectory properties throughout a phase space volume.

Boozer, A.H.

1984-02-01T23:59:59.000Z

452

Quantum Computing and Hidden Variables Scott Aaronson #  

E-Print Network [OSTI]

Quantum Computing and Hidden Variables Scott Aaronson # Institute for Advanced Study, Princeton of a hidden variable, then we could e#ciently solve problems that are believed to be intractable even powerful than the quantum computing model. PACS numbers: 03.65.Ta, 03.65.Ud, 03.67.Lx, 02.70.­c I

Aaronson, Scott

453

Deutsch-Jozsa algorithm for continuous variables  

E-Print Network [OSTI]

We present an idealized quantum continuous variable analog of the Deutsch-Jozsa algorithm which can be implemented on a perfect continuous variable quantum computer. Using the Fourier transformation and XOR gate appropriate for continuous spectra we show that under ideal operation to infinite precision that there is an infinite reduction in number of query calls in this scheme.

Arun K. Pati; Samuel L. Braunstein

2002-07-18T23:59:59.000Z

454

The Galex Ultraviolet Variability (GUVV) Catalog  

E-Print Network [OSTI]

We present Version 1.0 of the NASA Galaxy Evolution Explorer (GALEX) ultraviolet variability catalog (GUVV) that contains information on 84 time-variable and transient sources gained with simultaneous near and far ultraviolet photometric observations. These time-variable sources were serendipitously revealed in the various 1.2 degree star fields currently being surveyed by the GALEX satellite in two ultraviolet bands (NUV 1750-2750A, FUV 1350-1750A) with limiting AB magnitudes of 23-25. The largest-amplitude variable objects presently detected by GALEX are M-dwarf flare stars, which can brighten by 5-10 mag in both the NUV and FUV bands during short duration (< 500s) outbursts. Other types of large-amplitude ultraviolet variable objects include ab-type RR Lyrae stars, which can vary periodically by 2-5mag in the GALEX FUV band. This first GUVV catalog lists galactic positions and possible source identifications in order to provide the astronomical community with a list of time-variable objects that can now be repeatedly observed at other wavelengths. We expect the total number of time-variable source detections to increase as the GALEX mission progresses, such that later version numbers of the GUVV catalog will contain substantially more variable sources.

Barry Y. Welsh; Jonathan M. Wheatley; Kenneth Heafield; Mark Seibert; Stanley E. Browne; Samir Salim; R. Michael Rich; Tom A. Barlow; Luciana Bianchi; Yong-Ik Byun; Jose Donas; Karl Forster; Peter G. Friedman; Timothy M. Heckman; Patrick N. Jelinsky; Young-Wook Lee; Barry F. Madore; Roger F. Malina; D. Christopher Martin; Bruno Milliard; Patrick Morrissey; Susan G. Neff; David Schiminovich; Oswald H. W. Siegmund; Todd Small; Alex S. Szalay; Ted K. Wyder

2005-04-21T23:59:59.000Z

455

THE MULTI-USE STEINEL VARIABLE TEMPERATURE  

E-Print Network [OSTI]

THE MULTI-USE STEINEL VARIABLE TEMPERATURE ELECTRONICALLY CONTROLLED HEAT GUNTEMPERATURE RANGE 212 at the outlet nozzle will bum flesh. Do not tum on Heat Gun with hand in front of nozzle. DO NOT USE NEAR equipment Specifications Temperature Variable from 212" F to 1100° F Watts 1500W Weight 1.5 lbs. Supply

Kleinfeld, David

456

THE MULTI-USE STEINEL VARIABLE TEMPERATURE  

E-Print Network [OSTI]

THE MULTI-USE STEINEL VARIABLE TEMPERATURE ELECTRONICALLY CONTROLLED HEAT GUNTEMPERATURE RANGE 212 at the outlet nozzle will bum flesh. Do not tum on Heat Gun with hand in front of nozzle. DO NOT USE NEAR equipment Specifications Temperature Variable from 212° F to 1100° F Watts 1500W Weight 1.5 lbs. Supply

Kleinfeld, David

457

SLUDGE BATCH 7B GLASS VARIABILITY STUDY  

SciTech Connect (OSTI)

The Defense Waste Processing Facility (DWPF) is preparing to initiate processing Sludge Batch 7b (SB7b). In support of the upcoming processing, the Savannah River National Laboratory (SRNL) provided a recommendation to utilize Frits 418 with a 6% Na{sub 2}O addition (26 wt% Na{sub 2}O in sludge) and 702 with a 4% Na{sub 2}O addition (24 wt% Na{sub 2}O in sludge) to process SB7b. This recommendation was based on assessments of the compositional projections for SB7b available at the time from the Savannah River Remediation (SRR). To support qualification of SB7b, SRNL executed a variability study to assess the applicability of the current durability models for SB7b. The durability models were assessed over the expected composition range of SB7b, including potential caustic additions, combined with Frits 702 and 418 over a 32-40% waste loading (WL) range. Thirty four glasses were selected based on Frits 418 and 702 coupled with the sludge projections with an additional 4-6% Na{sub 2}O to reflect the potential caustic addition. Six of these glasses, based on average nominal sludge compositions including the appropriate caustic addition, were developed for both Frit 418 and Frit 702 at 32, 36 and 40% WL to provide coverage in the center of the anticipated SB7b glass region. All glasses were fabricated and characterized using chemical composition analysis, X-ray diffraction (XRD) and the Product Consistency Test (PCT). To comply with the DWPF Glass Product Control Program, a total of thirty four glasses were fabricated to assess the applicability of the current DWPF PCCS durability models. Based on the measured PCT response, all of the glasses were acceptable with respect to the Environmental Assessment (EA) benchmark glass regardless of thermal history. The NL[B] values of the SB7b variability study glasses were less than 1.99 g/L as compared to 16.695 g/L for EA. A small number of the D-optimally selected 'outer layer' extreme vertices (EV) glasses were not predictable using the current Product Composition Control System (PCCS) models for durability, but were acceptable compared to the EA glass when tested. These glasses fell outside of the lower 95% confidence band, which demonstrates conservatism in the model. A few of the glasses fell outside of the upper 95% confidence band; however, these particular glasses have normalized release values that were much lower than the values of EA and should be of no practical concern. Per the requirements of the DWPF Glass Product Control Program, the PCCS durability models have been shown to be applicable to the SB7b sludge system with a range of Na{sub 2}O concentrations blended with Frits 418 or 702. PCT results from the glasses fabricated as part of the variability study were shown to be predictable by the current DWPF PCCS models and/or acceptable with respect to the EA benchmark glass regardless of thermal history or compositional view.

Johnson, F.; Edwards, T.

2011-10-25T23:59:59.000Z

458

Continuous variable quantum teleportation with non-Gaussian resources  

E-Print Network [OSTI]

We investigate continuous variable quantum teleportation using non-Gaussian states of the radiation field as entangled resources. We compare the performance of different classes of degaussified resources, including two-mode photon-added and two-mode photon-subtracted squeezed states. We then introduce a class of two-mode squeezed Bell-like states with one-parameter dependence for optimization. These states interpolate between and include as subcases different classes of degaussified resources. We show that optimized squeezed Bell-like resources yield a remarkable improvement in the fidelity of teleportation both for coherent and nonclassical input states. The investigation reveals that the optimal non-Gaussian resources for continuous variable teleportation are those that most closely realize the simultaneous maximization of the content of entanglement, the degree of affinity with the two-mode squeezed vacuum and the, suitably measured, amount of non-Gaussianity.

F. Dell'Anno; S. De Siena; L. Albano Farias; F. Illuminati

2007-06-25T23:59:59.000Z

459

A variable-field permanent-magnet dipole for accelerators  

SciTech Connect (OSTI)

A new concept for a variable-field permanent-magnet dipole has been developed and fabricated at Los Alamos. The application requires an extremely uniform dipole field in the magnet aperture and precision variability over a large operating range. An iron-core permanent- magnet design using a shunt that was specially shaped to vary the field in a precise and reproducible fashion with shunt position. The key to this design is in the shape of the shunt. The field as a function of shunt position is very linear from 90% of the maximum field to 20% of the minimum field. The shaped shunt also results in a small maximum magnetic force attracting the shunt to the yoke allowing a simple mechanical design. Calculated and measured results agree well for the magnet.

Kraus, R.H. Jr.; Barlow, D.B.; Meyer, R.

1992-01-01T23:59:59.000Z

460

A variable-field permanent-magnet dipole for accelerators  

SciTech Connect (OSTI)

A new concept for a variable-field permanent-magnet dipole has been developed and fabricated at Los Alamos. The application requires an extremely uniform dipole field in the magnet aperture and precision variability over a large operating range. An iron-core permanent- magnet design using a shunt that was specially shaped to vary the field in a precise and reproducible fashion with shunt position. The key to this design is in the shape of the shunt. The field as a function of shunt position is very linear from 90% of the maximum field to 20% of the minimum field. The shaped shunt also results in a small maximum magnetic force attracting the shunt to the yoke allowing a simple mechanical design. Calculated and measured results agree well for the magnet.

Kraus, R.H. Jr.; Barlow, D.B.; Meyer, R.

1992-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Diagnostic for two-mode variable valve activation device  

DOE Patents [OSTI]

A method is provided for diagnosing a multi-mode valve train device which selectively provides high lift and low lift to a combustion valve of an internal combustion engine having a camshaft phaser actuated by an electric motor. The method includes applying a variable electric current to the electric motor to achieve a desired camshaft phaser operational mode and commanding the multi-mode valve train device to a desired valve train device operational mode selected from a high lift mode and a low lift mode. The method also includes monitoring the variable electric current and calculating a first characteristic of the parameter. The method also includes comparing the calculated first characteristic against a predetermined value of the first characteristic measured when the multi-mode valve train device is known to be in the desired valve train device operational mode.

Fedewa, Andrew M

2014-01-07T23:59:59.000Z

462

Numerical simulation of combined natural and forced convection during thermal-hydraulic transients. [LMFBR  

SciTech Connect (OSTI)

The single-phase COMMIX (COMponent MIXing) computer code performs fully three-dimensional, transient, thermal-hydraulic analyses of liquid-sodium LMFBR components. It solves the conservation equations of mass, momentum, and energy as a boundary-value problem in space and as an initial-value problem in time. The concepts of volume porosity, surface permeability and distributed resistance, and heat source have been employed in quasi-continuum (rod-bundle) applications. Results from three transient simulations involving forced and natural convection are presented: (1) a sodium-filled horizontal pipe initially of uniform temperature undergoing an inlet velocity rundown transient, as well as an inlet temperature transient; (2) a 19-pin LMFBR rod bundle undergoing a velocity transient; and, (3) a simulation of a water test of a 1/10-scale outlet plenum undergoing both velocity and temperature transients.

Domanus, H.M.; Sha, W.T.

1981-01-01T23:59:59.000Z

463

A study of stability indexes and vertical motion in relation to convective clouds over Texas  

E-Print Network [OSTI]

Totals Index 21 22 23 24 25 26 2'P 28 29 30 31 32 33 34 35 No, of cases 5 4 4 10 15 9 13 9 9 10 6 8 4 6 No. of cases with associated convective activity 1 3 0 3 5 4 5 1 0 3 0 0 1 1 0 IA & a s g& d a 8 I 5 e- rr gd a4 Fig, 12. Analysis... in the 3000-ft layer next to the ground. The wet-bulb potential temperature at 900 mb is used to compute the Jefferson Index (Jefferson, 1963) and the mean wet-bulb temperature in the lower 150 mb is used to compute the Fawbush-Miller Index (Miller, 1967b...

Booth, David Michael

1970-01-01T23:59:59.000Z

464

Quasiperiodicity, mode-locking, and universal scaling in Rayleigh-Benard convection  

SciTech Connect (OSTI)

This major review paper describes research on a model nonlinear dynamical system of small-aspect-ratio Rayleigh-Benard convection in {sup 3}He {minus} {sup 4}He mixtures. The nonlinear effects of mode locking and quasiperiodic behavior are described. Analysis techniques for characterizing the state of the dynamical system include Fourier transforms, Poincare sections, phase differences, transients, multifractal f({proportional to}) spectra and scaling function dynamics. Theoretical results such as the fractal staircase of mode-locked intervals and the Arnold tongues are reproduced in experimental data. New techniques for analyzing scaling dynamics are developed and discussed. This is a tutorial article that introduces the major important concepts in nonlinear dynamics and focuses on experimental problems and techniques. 77 refs.

Ecke, R.E.

1990-01-01T23:59:59.000Z

465

Solar Cycle Related Changes at the Base of the Convection Zone  

E-Print Network [OSTI]

The frequencies of solar oscillations are known to change with solar activity. We use Principal Component Analysis to examine these changes with high precision. In addition to the well-documented changes in solar normal mode oscillations with activity as a function of frequency, which originate in the surface layers of the Sun, we find a small but statistically significant change in frequencies with an origin at and below the base of the convection zone. We find that at r=(0.712^{+0.0097}_{-0.0029})R_sun, the change in sound speed is \\delta c^2 / c^2 = (7.23 +/- 2.08) x 10^{-5} between high and low activity. This change is very tightly correlated with solar activity. In addition, we use the splitting coefficients to examine the latitudinal structure of these changes. We find changes in sound speed correlated with surface activity for r >~ 0.9R_sun.

Charles S. Baldner; Sarbani Basu

2008-07-02T23:59:59.000Z

466

Atmospheric Radiation Measurement (ARM) Data from Los Angeles, California, to Honolulu, Hawaii for the Marine ARM GPCI Investigation of Clouds (MAGIC) Field Campaign (an AMF2 Deployment)  

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

From October 2012 through September 2013, the second ARM Mobile Facility (AMF2) was deployed on the container ship Spirit, operated by Horizon Lines, for the Marine ARM GPCI* Investigation of Clouds (MAGIC) field campaign. During approximately 20 round trips between Los Angeles, California, and Honolulu, Hawaii, AMF2 obtained continuous on-board measurements of cloud and precipitation, aerosols, and atmospheric radiation; surface meteorological and oceanographic variables; and atmospheric profiles from weather balloons launched every six hours. During two two-week intensive observational periods in January and July 2013, additional instruments were deployed and balloon soundings were be increased to every three hours. These additional data provided a more detailed characterization of the state of the atmosphere and its daily cycle during two distinctly different seasons. The primary objective of MAGIC was to improve the representation of the stratocumulus-to-cumulus transition in climate models. AMF2 data documented the small-scale physical processes associated with turbulence, convection, and radiation in a variety of marine cloud types.

467

Evaluation of the Multi-scale Modeling Framework Using Data from the Atmospheric Radiation Measurement Program  

SciTech Connect (OSTI)

One of the goals of the Atmospheric Radiation Measurement (ARM) program is to provide long-term observations for evaluating and improving cloud and radiation treatment in global climate models. Unfortunately, the traditional parametric approach of diagnosing cloud and radiation properties for gridcells that are tens to hundreds kilometers across from large-scale model fields is not well suited for comparison with time series of ground based observations at selected locations. A recently emerging approach called a multi-scale modeling framework (MMF) has shown promise to bridge the scale gap. The MMF consists of a two-dimensional or small three-dimensional cloud resolving model (CRM) embedded into each grid column of the Community Atmospheric Model (CAM), thereby computing cloud properties at a scale that is more consistent with observations. We present a comparison of data from two ARM sites, one at the Southern Great Plains (SGP) in Oklahoma and one at Nauru Island in the Tropical Western Pacific (TWP) region, with output from both the CAM and MMF. Two sets of one year long simulations are considered: one using climatological sea surface temperatures (SST) and another using 1999 SST. Each set includes a run with the MMF as well as the CAM run with traditional or standard cloud and radiation treatment. Time series of cloud fraction, precipitation intensity, and downwelling solar radiation flux at the surface are statistically analyzed. For the TWP site, nearly all parameters of frequency distributions of these variables from the MMF run are shown to be more consistent with observation than those from the CAM run. This change is attributed to the improved representation of convective clouds in the MMF compared to the conventional climate model. For the SGP, the MMF shows little to no improvement in predicting the same quantities. Possible causes of this lack of improvement are discussed.

Ovtchinnikov, Mikhail; Ackerman, Thomas P.; Marchand, Roger T.; Khairoutdinov, Marat

2006-05-01T23:59:59.000Z

468

A comparison of two variables in relaxation  

E-Print Network [OSTI]

A COMPARISON OF TWO VARIABLES IN RELAXATION A Thesis by PAUL EDWIN TURNER Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE May 1974 Major Subject...: Psychology A COMPARiSON OF TWO VARIABLES IN RELAXATION A Thesis by PAUL EDWIN TURNER Approved as to style and content by: (Chairman of Committ Head of Dep tment Member ?2 J L, ~Xi~ Member M-. ~~2 y May 1974 ABSTRACT A Comparison of Two Variable...

Turner, Paul Edwin

1974-01-01T23:59:59.000Z

469

Intra-canopy variability of fruit growth rate in peach trees grafted on rootstocks with different vigour-control capacity  

E-Print Network [OSTI]

Intra-canopy variability of fruit growth rate in peach trees grafted on rootstocks with different research was to study intra-canopy variability in fruit growth under conditions of low fruit-to- fruit vertically into five layers.The diameter of 12 fruit per canopy layer was measured early in the growing

DeJong, Theodore

470

Constructive Contrasts Between Modeled and Measured Climate  

E-Print Network [OSTI]

Constructive Contrasts Between Modeled and Measured Climate Responses Over a Regional Scale of simulated net primary production (NPP) to climate variables and the response observed in field measurements of NPP. Residual contrasts com- pared deviations of NPP from the empirical surface to identify groupings

Hargrove, William W.

471

Variable volume architecture : expanding the boundary  

E-Print Network [OSTI]

Research into the creation of a Variable Volume Architecture is explored through a series of proposals and projects. An argument is established to develop the means and methods of achieving an architecture of transformation. ...

Saheba, Asheshh (Asheshh Mohit), 1972-

2001-01-01T23:59:59.000Z

472

Inserting Group Variables into Fluid Mechanics  

E-Print Network [OSTI]

A fluid, like a quark-gluon plasma, may possess degrees of freedom indexed by a group variable, which retains its identity even in the fluid/continuum description. Conventional Eulerian fluid mechanics is extended to encompass this possibility.

R. Jackiw

2004-10-28T23:59:59.000Z

473

Energy Savings of Variable Speed Motors  

E-Print Network [OSTI]

This paper investigates the energy savings available by utilizing variable speed motors on pump and fan applications. Conventional control of flow or pressure in process plants is normally accomplished by throttling the various streams with control...

Fishel, F. D.

1979-01-01T23:59:59.000Z

474

Variable-Rate State Gasoline Taxes  

E-Print Network [OSTI]

J Bradshaw, "SLate ’F~es’ Gasoline Tax So ~t Wdl Rise," TheVarlable-Rate State Gasoline Taxers Jeffrey Ang-Olson MartinVariable-Rate State Gasoline Taxes Jeffrey Ang-Olson

Ang-Olson, Jeffrey; Wachs, Martin; Taylor, Brian D.

2000-01-01T23:59:59.000Z

475

UselessVariable Elimination Olin Shivers  

E-Print Network [OSTI]

flow analysis on the CPS inter­ mediate form. (I use a CPS representation essentially identical­passing style (CPS) intermediate representations, continuation variables are frequently passed around loops

Shivers, Olin

476

Hybrid permanent magnet and variable reluctance generator  

SciTech Connect (OSTI)

This patent describes a hybrid electrical generator. It comprises: a permanent magnet generator having a permanent magnet rotor mounted on a shaft, the permanent magnet generator providing an output voltage over an operating range which falls in response to an increasing electrical load; a variable reluctance generator having a rotor mounted on the shaft with excitation of a stator of the variable reluctance generator being provided from the permanent magnet generator, the variable reluctance generator providing an output voltage which varies in response to an increasing electrical load over an operating range; and a voltage regulator, responsive to combined output voltages of the generators, for controlling the output voltage provided by the variable reluctance generator.

Vaidya, J.; Belanger, D.J.

1990-09-25T23:59:59.000Z

477

The Energy-Dependence of GRB Minimum Variability Timescales  

E-Print Network [OSTI]

We constrain the minimum variability timescales for 938 GRBs observed by the Fermi/GBM instrument prior to July 11, 2012. The tightest constraints on progenitor radii derived from these timescales are obtained from light curves in the hardest energy channel. In the softer bands -- or from measurements of the same GRBs in the hard X-rays from Swift -- we show that variability timescales tend to be a factor 2--3 longer. Applying a survival analysis to account for detections and upper limits, we find median minimum timescale in the rest frame for long-duration and short-duration GRBs of 45 ms and 10 ms, respectively. Fewer than 10% of GRBs show evidence for variability on timescales below 2 ms. These shortest timescales require Lorentz factors $\\gtrsim 400$ and imply typical emission radii $R \\approx 1 {\\times} 10^{14}$ cm for long-duration GRBs and $R \\approx 3 {\\times} 10^{13}$ cm for short-duration GRBs. We discuss implications for the GRB fireball model and investigate whether GRB minimum timescales evolve w...

Golkhou, V Zach; Littlejohns, Owen M

2015-01-01T23:59:59.000Z

478

Variability in the North Atlantic Deep Western Boundary Current : upstream causes and downstream effects as observed at Line W  

E-Print Network [OSTI]

The variability in the DWBC, its connection to the forcing in the northern North Atlantic and interaction with the Gulf Stream were explored from a combination of remote sensing and in-situ measurements in the western North ...

Peña-Molino, Beatriz

2010-01-01T23:59:59.000Z

479

Developing Human Performance Measures  

SciTech Connect (OSTI)

Through the reactor oversight process (ROP), the U.S. Nuclear Regulatory Commission (NRC) monitors the performance of utilities licensed to operate nuclear power plants. The process is designed to assure public health and safety by providing reasonable assurance that licensees are meeting the cornerstones of safety and designated crosscutting elements. The reactor inspection program, together with performance indicators (PIs), and enforcement activities form the basis for the NRC’s risk-informed, performance based regulatory framework. While human performance is a key component in the safe operation of nuclear power plants and is a designated cross-cutting element of the ROP, there is currently no direct inspection or performance indicator for assessing human performance. Rather, when human performance is identified as a substantive cross cutting element in any 1 of 3 categories (resources, organizational or personnel), it is then evaluated for common themes to determine if follow-up actions are warranted. However, variability in human performance occurs from day to day, across activities that vary in complexity, and workgroups, contributing to the uncertainty in the outcomes of performance. While some variability in human performance may be random, much of the variability may be attributed to factors that are not currently assessed. There is a need to identify and assess aspects of human performance that relate to plant safety and to develop measures that can be used to successfully assure licensee performance and indicate when additional investigation may be required. This paper presents research that establishes a technical basis for developing human performance measures. In particular, we discuss: 1) how historical data already gives some indication of connection between human performance and overall plant performance, 2) how industry led efforts to measure and model human performance and organizational factors could serve as a data source and basis for a framework, 3) how our use of modeling and simulation techniques could be used to develop and validate measures of human performance, and 4) what the possible outcomes are from this research as the modeling and simulation efforts generate results.

Jeffrey Joe; Bruce Hallbert; Larry Blackwood; Donald Dudehoeffer; Kent Hansen

2006-05-01T23:59:59.000Z

480

Cold domes over the warm pool: a study of the properties of cold domes produced by mesoscale convective systems during TOGA COARE  

E-Print Network [OSTI]

Mesoscale convective systems (MCSs) are known to cool the subcloud layer by the introduction of penetrative downdrafts to the surface, resulting in the formation of cold domes (also known as cold pools). Five MCSs sampled during the Tropical Ocean...

Caesar, Kathy-Ann Lois

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measurement variable convection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Experimental study of alumina-water and zirconia-water nanofluids convective heat transfer and viscous pressure loss in Laminar regime  

E-Print Network [OSTI]

The objective of this study is to evaluate experimentally the convective heat transfer and viscous pressure loss characteristics of alumina-water and zirconia-water nanofluids. Nanofluids are colloidal dispersions of ...

Rea, Ulzie L

2008-01-01T23:59:59.000Z

482

Correlation between present-day model simulation of Arctic cloud radiative forcing and sea ice consistent with positive winter convective cloud feedback  

E-Print Network [OSTI]

A positive feedback on winter sea-ice loss, based on warming due to radiative forcing caused by the onset of convective clouds in response to sea-ice loss, has recently been proposed. This feedback has thus far been ...

Emanuel, Kerry Andrew

483

Quarterly Journal of the Royal Meteorological Society Q. J. R. Meteorol. Soc. 140: 500516, January 2014 B Phenomenology of Sahelian convection observed in Niamey  

E-Print Network [OSTI]

2014 B Phenomenology of Sahelian convection observed in Niamey during the early monsoon C. Dionea Citation: Dione C, Lothon M, Badiane D, Campistron B, Couvreux F, Guichard F, Sall SM. 2014. Phenomenology

Guichard, Francoise

484

Impact of a modified convective scheme on the Madden-Julian Oscillation and El Nin~oSouthern Oscillation in a coupled climate  

E-Print Network [OSTI]

. Richard Peltier,2 and Guang Jun Zhang3 Received 9 May 2007; revised 6 July 2007; accepted 3 August 2007. Vettoretti, W. R. Peltier, and G. J. Zhang (2007), Impact of a modified convective scheme on the Madden

Peltier, W. Richard

485

MODELING HEAT TRANSFER IN SPENT FUEL TRANSFER CASK NEUTRON SHIELDS – A CHALLENGING PROBLEM IN NATURAL CONVECTION  

SciTech Connect (OSTI)

In the United States, commercial spent nuclear fuel is typically moved from spent fuel pools to outdoor dry storage pads within a transfer cask system that provides radiation shielding to protect personnel and the surrounding environment. The transfer casks are cylindrical steel enclosures with integral gamma and neutron radiation shields. Since the transfer cask system must be passively cooled, decay heat removal from spent nuclear fuel canister is limited by the rate of heat transfer through the cask components, and natural convection from the transfer cask surface. The primary mode of heat transfer within the transfer cask system is conduction, but some cask designs incorporate a liquid neutron shield tank surrounding the transfer cask structural shell. In these systems, accurate prediction of natural convection within the neutron shield tank is an important part of assessing the overall thermal performance of the transfer cask system. The large-scale geometry of the neutron shield tank, which is typically an annulus approximately 2 meters in diameter but only 10-15 cm in thickness, and the relatively small scale velocities (typically less than 5 cm/s) represent a wide range of spatial and temporal scales that contribute to making this a challenging problem for computational fluid dynamics (CFD) modeling. Relevant experimental data at these scales are not available in the literature, but some recent modeling studies offer insights into numerical issues and solutions; however, the geometries in these studies, and for the experimental data in the literature at smaller scales, all have large annular gaps that are not prototypic of the transfer cask neutron shield. This paper proposes that there may be reliable CFD approaches to the transfer cask problem, specifically coupled steady-state solvers or unsteady simulations; however, both of these solutions take significant computational effort. Segregated (uncoupled) steady state solvers that were tested did not accurately capture the flow field and heat transfer distribution in this application. Mesh resolution, turbulence modeling, and the tradeoff between steady state and transient solutions are addressed. Because of the critical nature of this application, the need for new experiments at representative scales is clearly demonstrated.

Fort, James A.; Cuta, Judith M.; Bajwa, C.; Baglietto, E.

2010-07-18T23:59:59.000Z

486

Guide to transverse projections and mass-constraining variables  

SciTech Connect (OSTI)

This paper seeks to demonstrate that many of the existing mass-measurement variables proposed for hadron colliders (m{sub T}, m{sub eff}, m{sub T2}, missing p-vector{sub T}, h{sub T}, {radical}(s-circumflex){sub min}, etc.) are far more closely related to each other than is widely appreciated, and indeed can all be viewed as a common mass-bound specialized for a variety of purposes. A consequence of this is that one may understand better the strengths and weaknesses of each variable, and the circumstances in which each can be used to best effect. In order to achieve this, we find it necessary first to revisit the seemingly empty and infertile wilderness populated by the subscript 'T' (as in 'pe{sub T}') in order to remind ourselves what this process of transversification actually means. We note that, far from being simple, transversification can mean quite different things to different people. Those readers who manage to battle through the barrage of transverse notation distinguishing 'T' from 'v' or or from 'o', and 'early projection' from 'late projection', will find their efforts rewarded towards the end of the paper with (i) a better understanding of how collider mass variables fit together, (ii) an appreciation of how these variables could be generalized to search for things more complicated than supersymmetry, (iii) will depart with an aversion to thoughtless or naieve use of the so-called 'transverse methods' of any of the popular computer Lorentz-vector libraries, and (iv) will take care in their subsequent papers to be explicit about which of the 61 identified variants of the 'transverse mass' they are employing.

Barr, A. J. [Department of Physics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Khoo, T. J.; Lester, C. G. [Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE (United Kingdom); Konar, P. [Theoretical Physics Group, Physical Research Laboratory, Ahmedabad, Gujarat - 380 009 (India); Kong, K. [Department of Physics and Astronomy, University of Kansas, Lawrence, KA 66045 (United States); Matchev, K. T.; Park, M. [Department of Physics, University of Florida, Gainesville, Florida 32611 (United States)

2011-11-01T23:59:59.000Z

487

Phenotypic and genetic relationships between certain body measurements and milk production of first lactation Holsteins  

E-Print Network [OSTI]

2 The relative improvement expected to be gained by selection based 3olely on body measurement variables APPENDIX TABLES 3 Analysis cf variance to measure importance of in- breeding 4 Analysis of variance to measure importance of variation due... production and six body measurements 9 The within-year, within-sire correlations between nine variables measured on dam and daughter Page 21 LI 43 44 45 46 47 4 8 49 Phenotypic and Genetic Relationships Between Certain Body Measurements and Milk...

Johnson, Joseph Calbert

2013-10-04T23:59:59.000Z

488

Evaluation of the simulated interannual and subseasonal variability  

E-Print Network [OSTI]

the conventional parameterizations of convection, clouds and boundary layer with a cloud-resolving model embedded-2004 sea surface temperature (SST) and sea ice distributions as prescribed boundary conditions. Particular to the spectra derived from observations, and show a robust MJO, Kelvin waves and Rossby waves with phase speeds

Randall, David A.

489

Spatial variability of summer precipitation related to the  

E-Print Network [OSTI]

to the observed diurnal patterns of precipitation over the central U.S. #12;Shading ­ meridional wind speed (Shading denotes meridional wind speed) P winds #12; Air temperature (shading; K) and zonal temperature #12;Convective P frequency Vertical wind in the model Moisture convergence at 850 hPa Vertical

Yang, Zong-Liang

490

Convective currents in nucleate pool boiling and their effects on the heat flux from varying diameter flat plate heating elements  

E-Print Network [OSTI]

investigation was conducred to amine the effects of convection currents in nucleate oool boil ing and to determine the changes in critical heat flux caused by varying the diameter of horizontal flat olate heating surfaces. Freon 113 (Trichlorotrifluoroethane... by high energy costs and thc need to economize in industrial heat transfer applications . I'nucleate boiling is a very efficient neans of heat transfer because of the large sur ace areas involved in vaporization of the bulk fluid. as bubbles form...

Morford, Peter Stephen

1980-01-01T23:59:59.000Z

491

An analysis of modified convective available potential energy and Richardson number in mid-latitude squall line environments  

E-Print Network [OSTI]

modified convective available potential energy (MCAPE) and Richardson number (MRI) were computed for each upper air sounding in a synoptic ? scale data network. The resulting fields were contoured and compared to the development, growth and decay of mid... ? latitude squall lines in several cases studies. The results indicate that, though the squall lines remained in the vicinity of MCAPE maxima and MRI minima there was no quantitative association. The squall lines also appeared to avoid these regions...

Stricherz, James Nicholas

1989-01-01T23:59:59.000Z

492

Cloud speed impact on solar variability scaling â?? Application to the wavelet variability model  

E-Print Network [OSTI]

Kleissl, J. , 2013. Deriving cloud velocity from an array ofCloud Speed Impact on Solar Variability Scaling -this work, we determine from cloud speeds. Cloud simulator

Lave, Matthew; Kleissl, Jan

2013-01-01T23:59:59.000Z

493

Longwave thermal infrared spectral variability in individual rocks  

SciTech Connect (OSTI)

A hyperspectral imaging spectrometer measuring in the longwave thermal infrared (7.6-11.6 {micro}m) with a spatial resolution less than 4 mm was used in the field to observe the variability of emissivity spectra within individual rocks. The rocks were obtained commercially, were on the order of 20 cm in size and were selected to have distinct spectral features: they include alabaster (gypsum), soapstone (steatite with talc), obsidian (volcanic glass), norite (plagioclase and orthopyroxene), and 'jasper' (silica with iron oxides). The advantages of using an imaging spectrometer to spectrally characterize these rocks are apparent. Large spectral variations were observed within individual rocks that may be attributed to roughness, surface geometry, and compositional variation. Non-imaging spectrometers would normally miss these variations as would small samples used in laboratory measurements, spatially averaged spectra can miss the optimum spectra for identification materials and spatially localized components of the rock can be obscured.

Balick, Lee K [Los Alamos National Laboratory; Gillespie, Alan [UN. WASHINGTON; French, Andrew [USDA-ARS; Danilina, Iryna [UN. WASHINGTON

2008-01-01T23:59:59.000Z

494

STELLAR AGES AND CONVECTIVE CORES IN FIELD MAIN-SEQUENCE STARS: FIRST ASTEROSEISMIC APPLICATION TO TWO KEPLER TARGETS  

SciTech Connect (OSTI)

Using asteroseismic data and stellar evolution models we obtain the first detection of a convective core in a Kepler field main-sequence star, putting a stringent constraint on the total size of the mixed zone and showing that extra mixing beyond the formal convective boundary exists. In a slightly less massive target the presence of a convective core cannot be conclusively discarded, and thus its remaining main-sequence lifetime is uncertain. Our results reveal that best-fit models found solely by matching individual frequencies of oscillations corrected for surface effects do not always properly reproduce frequency combinations. Moreover, slightly different criteria to define what the best-fit model is can lead to solutions with similar global properties but very different interior structures. We argue that the use of frequency ratios is a more reliable way to obtain accurate stellar parameters, and show that our analysis in field main-sequence stars can yield an overall precision of 1.5%, 4%, and 10% in radius, mass, and age, respectively. We compare our results with those obtained from global oscillation properties, and discuss the possible sources of uncertainties in asteroseismic stellar modeling where further studies are still needed.

Silva Aguirre, V.; Christensen-Dalsgaard, J.; Chaplin, W. J. [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Basu, S.; Deheuvels, S. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Brandao, I. M.; Cunha, M. S.; Sousa, S. G. [Centro de Astrofisica and Faculdade de Ciencias, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Dogan, G. [High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO 80307 (United States); Metcalfe, T. S. [Space Science Institute, Boulder, CO 80301 (United States); Serenelli, A. M.; Garcia, R. A. [Kavli Institute for Theoretical Physics, Santa Barbara, CA 93106 (United States); Ballot, J. [Institut de Recherche en Astrophysique et Planetologie, CNRS, 14 avenue Edouard Belin, F-31400 Toulouse (France); Weiss, A. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85748 Garching bei Muenchen (Germany); Appourchaux, T. [Institut d'Astrophysique Spatiale, Universite Paris Sud-CNRS (UMR8617) Batiment 121, F-91405 Orsay Cedex (France); Casagrande, L. [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, The Australian National University, ACT 2611 (Australia); Cassisi, S. [INAF-Astronomical Observatory of Teramo, Via M. Maggini sn, I-64100 Teramo (Italy); Creevey, O. L. [Laboratoire Lagrange, Universite de Nice Sophia-Antipolis, CNRS, I-06300 Nice, France. (France); Lebreton, Y. [Observatoire de Paris, GEPI, CNRS UMR 8111, F-92195 Meudon (France); Noels, A. [Institute of Astrophysics and Geophysics, University of Liege, B-4000 Liege (Belgium); and others

2013-06-01T23:59:59.000Z

495

Using cloud resolving model simulations of deep convection to inform cloud parameterizations in large-scale models  

SciTech Connect (OSTI)

Cloud parameterizations in large-scale models struggle to address the significant non-linear effects of radiation and precipitation that arise from horizontal inhomogeneity in cloud properties at scales smaller than the grid box size of the large-scale models. Statistical cloud schemes provide an attractive framework to self-consistently predict the horizontal inhomogeneity in radiation and microphysics because the probability distribution function (PDF) of total water contained in the scheme can be used to calculate these non-linear effects. Statistical cloud schemes were originally developed for boundary layer studies so extending them to a global model with many different environments is not straightforward. For example, deep convection creates abundant cloudiness and yet little is known about how deep convection alters the PDF of total water or how to parameterize these impacts. These issues are explored with data from a 29 day simulation by a cloud resolving model (CRM) of the July 1997 ARM Intensive Observing Period at the Southern Great Plains site. The simulation is used to answer two questions: (a) how well can the beta distribution represent the PDFs of total water relative to saturation resolved by the CRM? (b) how can the effects of convection on the PDF be parameterized? In addition to answering these questions, additional sections more fully describe the proposed statistical cloud scheme and the CRM simulation and analysis methods.

Klein, Stephen A.; Pincus, Robert; Xu, Kuan-man

2003-06-23T23:59:59.000Z

496

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

E-Print Network [OSTI]

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...

Deguen, Renaud

2013-01-01T23:59:59.000Z

497

Electron cyclotron emission spectrometry on the Tokamak a Configuration Variable  

SciTech Connect (OSTI)

Electron cyclotron emission (ECE) measurements are an important component of the diagnostic suite on the Tokamak a Configuration Variable (TCV) [F. Hoffman et al., Plasma Phys. Controlled Fusion 36, B277 (1994)]. A recently installed, 24-channel dual-conversion heterodyne radiometer covering the radio frequency range 65-100 GHz and viewing from the low-field side (LFS) of the tokamak greatly enhances the system and, in combination with an existing radiometer viewing from the high-field side (HFS), allows simultaneous measurements of emission from the HFS and LFS. In addition, the new radiometer has multiple lines of sight that can receive the emission perpendicular to the toroidal magnetic field as well as with a finite k{sub parallel} (wave vector parallel to magnetic field). Such flexibility allows the LFS radiometer to make standard measurements of thermal emission and nonstandard measurements of nonthermal, anisotropic emission. The toroidal line of sight allows access to overdense plasma via mode converted emission. The enhanced ECE diagnostic is described and examples of measurements made in various configurations are presented.

Klimanov, I.; Porte, L.; Alberti, S.; Blanchard, P.; Fasoli, A.; Goodman, T.P. [Centre de Recherches en Physique des Plasmas (CRPP), Association EURATOM-Confederation Suisse, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015, Lausanne (Switzerland)

2005-09-15T23:59:59.000Z

498

Interannual variability of Caribbean rainfall, ENSO and the Atlantic Ocean  

E-Print Network [OSTI]

Interannual variability of Caribbean rainfall, ENSO and the Atlantic Ocean Alessandra Giannini variability of Caribbean-Central Americanrainfall are examined. The atmosphericcirculation over this region- ature (SST) variability associated with Caribbean rainfall, as selected by canonical correlation

Columbia University

499

Software Enabled Virtually Variable Displacement Pumps -Theoretical and Experimental Studies  

E-Print Network [OSTI]

Software Enabled Virtually Variable Displacement Pumps - Theoretical and Experimental Studies the functional equivalent of a variable displacement pump. This approach combines a fixed displacement pump valve control, without many of the shortcomings of commercially available variable displacement pumps

Li, Perry Y.

500

The use of 'race' as a variable in biomedical research  

E-Print Network [OSTI]

be used as a variable in biomedical research but mainly toRace’ as a Variable in Biomedical Research A dissertationRace’ as a Variable in Biomedical Research…………. Manifest,

Efstathiou, Sophia

2009-01-01T23:59:59.000Z