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1

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

2

Midlatitude Continental Convective Clouds Experiment Science Objective  

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 SurfacesResource Program PreliminaryA3, 1999of Science (SC)RegionalsMidlatitude

3

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

4

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

5

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

6

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

7

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

8

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

9

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

10

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

11

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

12

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

13

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

14

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

15

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Surface Meteorology (williams-surfmet)  

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

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Williams, Christopher; Jensen, Mike

16

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Vertical Air Motion (williams-vertair)  

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

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Williams, Christopher; Jensen, Mike

17

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Parcivel Disdrometer (williams-disdro)  

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

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Williams, Christopher; Jensen, Mike

18

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, 449 MHz Profiler(williams-449_prof)  

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

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Williams, Christopher; Jensen, Mike

19

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, 449 MHz Profiler(williams-449_prof)  

SciTech Connect (OSTI)

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Williams, Christopher; Jensen, Mike

2012-11-06T23:59:59.000Z

20

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Parcivel Disdrometer (williams-disdro)  

SciTech Connect (OSTI)

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Williams, Christopher; Jensen, Mike

2012-11-06T23:59:59.000Z

Note: This page contains sample records for the topic "midlatitude continental convective" 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

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Vertical Air Motion (williams-vertair)  

SciTech Connect (OSTI)

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Williams, Christopher; Jensen, Mike

2012-11-06T23:59:59.000Z

22

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Surface Meteorology (williams-surfmet)  

SciTech Connect (OSTI)

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Williams, Christopher; Jensen, Mike

2012-11-06T23:59:59.000Z

23

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, S-band Radar (williams-s_band)  

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

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Williams, Christopher

24

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, S-band Radar (williams-s_band)  

SciTech Connect (OSTI)

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Williams, Christopher

2012-11-06T23:59:59.000Z

25

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E)  

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 : XDCResearchWarmingMethane Background Information Outreach Home Room Related

26

ARM - Field Campaign - Midlatitude Continental Convective Clouds Experiment  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD) by Microtops Atmospheric Optical Depth (AOD) by Microtops ARM Data(MC3E) Experiment (MC3E)

27

ARM - Field Campaign - Midlatitude Continental Convective Clouds Experiment  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD) by Microtops Atmospheric Optical Depth (AOD) by Microtops ARM Data(MC3E) Experiment

28

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

29

DOE/SC-ARM-14-012 The Mid-latitude Continental Convective Clouds  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to UserProduct: CrudeOffice ofINL is a U.S. Department of42 The

30

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

31

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

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

40

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

42

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

43

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

44

An Idealized Cloud-Resolving Framework for the Study of Midlatitude Diurnal Convection over Land  

E-Print Network [OSTI]

LINDA SCHLEMMER Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland CATHY Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland CHRISTOPHER S. BRETHERTON for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland (Manuscript received 11 August 2010, in final

Bretherton, Chris

45

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

46

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

47

Interactions between the tropical ISO and midlatitude low-frequency flow  

E-Print Network [OSTI]

Interactions between the tropical ISO and midlatitude low-frequency flow Lin-Lin Pan Æ Tim Li Abstract In this study, we investigate the interaction between the tropical Intraseasonal Oscillation (ISO study the role of the syn- optic eddy feedback in the midlatitude response to the tropical ISO forcing

Li, Tim

48

A Climatology of Midlatitude Continental Clouds from the ARM SGP Central Facility. Part II: Cloud Fraction and Surface Radiative Forcing  

E-Print Network [OSTI]

at the Department of Energy Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Central Facility and for single-layered low (0­3 km), middle (3­6 km), and high clouds ( 6 km) using ARM SCF ground-based paired-looking standard precision spectral pyranometers and precision infrared radiometer measurements with uncertainties

Dong, Xiquan

49

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

50

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

51

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

52

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

53

Friction in Mid-latitude Bob Plant, Stephen Belcher, Bob Beare, Andy Brown  

E-Print Network [OSTI]

Friction in Mid-latitude Cyclones Ian Boutle Bob Plant, Stephen Belcher, Bob Beare, Andy Brown #12;Motivation · Many studies have shown the significance of friction in formation and dissipation of cyclones Dt = + � . F . Diabatic Term: · Surface heat fluxes · Latent heat fluxes Frictional Term

Plant, Robert

54

LOCATION AND MAGNETOSPHERIC MAPPING OF SATURN'S MID-LATITUDE INFRARED AURORAL OVAL  

SciTech Connect (OSTI)

Previous observations of Saturn's infrared aurorae have shown that a mid-latitude aurora exists significantly equatorward of the main auroral oval. Here, we present new results using data from four separate observing runs in 1998, 2003, 2008, and 2010. When combined, these provide a view of the mid-latitude aurora under a considerable range of viewing conditions, allowing the first calculation of the latitudinal position of this aurora to be made. This has shown that the mid-latitude aurora is located at the magnetic footprint of the region within the magnetosphere where the initial breakdown in corotation occurs, between 3 R {sub S} and the orbit of Enceladus ({approx}3.95 R {sub S}). We also confirm that this aurora is a continuous stable feature over a period of more than a decade and that an oval morphology is likely. When combined, these results indicate that the mid-latitude auroral oval is formed by currents driven by the breakdown process within the magnetosphere, in turn caused by mass loading from the torus of Enceladus, analogous with the volcanic moon Io's dominant role in the formation of Jupiter's main auroral oval.

Stallard, Tom; Melin, Henrik; Cowley, Stanley W. H. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Miller, Steve [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Lystrup, Makenzie B., E-mail: tss@ion.le.ac.u [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, CO 80303-7814 (United States)

2010-10-10T23:59:59.000Z

55

The WRF nested within the CESM: Simulations of a midlatitude cyclone over the Southern Great Plains  

E-Print Network [OSTI]

and Forecasting (WRF) model is nested within the global Community Earth System Model (CESM). Since both models System Model (CESM). This system is validated for the simulation of a midlatitude cyclongesis event over system in which the Weather Research and Forecasting model (WRF) is nested within the Community Earth

Ohta, Shigemi

56

Influence of Midlatitude Winds on the Stratification of the Equatorial Thermocline* MASAMI NONAKA  

E-Print Network [OSTI]

, Ekman pumping, and entrainment in the subpolar ocean are examined. The effects of a "sponge layer" adjacent to the northern boundary of the basin are also assessed. Solutions are forced by idealized zonal winds with strong or weak midlatitude westerlies, and they are found in rectangular basins that extend

Xie, Shang-Ping

57

Drilling Report- First CSDP (Continental Scientific Drilling...  

Open Energy Info (EERE)

the hydrogeochemistry of a subsurface geothermal outflow zone of the caldera near the source of convective upflow, (2) to obtain structural and stratigraphic information from...

58

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

59

Continentality: its estimation and physical significance  

E-Print Network [OSTI]

the North American continent as a whole. In addition, the Rocky Mountain and Great Lakes-Appalachia regions were chosen for mesoscale analysis in order to determine what effect elevation and large water bod1es have on lag. Isopleth analyses... . . . . . . . . . . . . . . . . . . 57 LIST OF FIGURES Figure 1 Continentality of North America according to Conrad 2 Stations used for continental scale analysis. 3 Rocky Mountain stations 4 Great Lakes-Appalachia stations Page 15 16 17 5 (Jun + Jul) - (Dec + Jan) radiation...

Yee Fong, Juan Manuel

1985-01-01T23:59:59.000Z

60

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

62

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

63

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

64

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

65

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

66

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

67

Impact of rising greenhouse gases on mid-latitude storm tracks and associated hydroclimate variability and change  

SciTech Connect (OSTI)

Project Summary This project aimed to advance physical understanding of how and why the mid-latitude jet streams and storm tracks shift in intensity and latitude in response to changes in radiative forcing with an especial focus on rising greenhouse gases. The motivation, and much of the work, stemmed from the importance that these mean and transient atmospheric circulation systems have for hydroclimate. In particular drying and expansion of the subtropical dry zones has been related to a poleward shift of the mid-latitude jets and storm tracks. The work involved integrated assessment of observation and model projections as well as targeted model simulations.

Seager, Richard

2014-12-08T23:59:59.000Z

68

A method for interpreting continental and analytic epistemology  

E-Print Network [OSTI]

of this thesis is to investigate the feasibility and profitability of communication between analytic and continental philosophy in epistemology. Wittgenstein's concept of language games will be used to frame the issue', continental and analytic philosophers play...

McCoy, Sarah Ruth

1999-01-01T23:59:59.000Z

69

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

70

What is this MCMS? MCMS stands for the MAP Climatology of Mid-latitude Storminess dataset (see  

E-Print Network [OSTI]

arguments. Cyclone tracking is treated as a separate process and product (not shown here for brevity) depression around a mid-latitude baroclinic cyclone (or just cyclone). MCMS rests on two operations: 1) finding and tracking cyclones and 2) objectively delineating the area under each cyclones influence

71

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

72

Continental Biofuels Corporation | Open Energy Information  

Open Energy Info (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 Office of InspectorConcentrating Solar Power Basics (The following text is derivedCoReturn toContinental Biofuels

73

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

74

CSDP: Seismology of continental thermal regime  

SciTech Connect (OSTI)

This is a progress report for the past one year of research (year 2 of 5-year project) under the project titled CSDP: Seismology of Continental Thermal Regime'', in which we proposed to develop seismological interpretation theory and methods applicable to complex structures encountered in continental geothermal areas and apply them to several candidate sites for the Continental Scientific Drilling Project. During the past year, two Ph.D. thesis works were completed under the present project. One is a USC thesis on seismic wave propagation in anisotropic media with application to defining fractures in the earth. The other is a MIT thesis on seismic Q and velocity structure for the magma-hydrothermal system of the Valles Caldera, New Mexico. The P.I. co-organized the first International Workshop on Volcanic Seismology at Capri, Italy in October 1988, and presented the keynote paper on the state-of-art of volcanic seismology''. We presented another paper at the workshop on Assorted Seismic Signals from Kilauea Volcano, Hawaii. Another international meeting, namely, the Chapman Conference on seismic anisotropy in the earth's crust at Berkeley, California in May 1988, was co-organized by the co-P.I. (P.C.L), and we presented our work on seismic waves in heterogeneous and anisotropic media. Adding the publications and presentations made in the past year to the list for the preceding year, the following table lists 21 papers published, submitted or presented in the past two years of the present project. 65 refs., 334 figs., 1 tab.

Aki, K.

1989-04-01T23:59:59.000Z

75

Continental breakup and the dawn of humankind  

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 DocumentationP-Series to User GroupInformationE-Gov Contacts for E-GovContactsContinental

76

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

77

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

78

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

79

Midlatitude Cirrus Clouds and Multiple Tropopauses from a 2002-2006 Climatology over the SIRTA Observatory  

E-Print Network [OSTI]

This study present a comparison of lidar observations of midlatitude cirrus clouds over the SIRTA observatory between 2002 and 2006 with multiple tropopauses (MT) retrieved from radiosounding temperature profiles. The temporal variability of MT properties (frequency, thickness) are discussed. Results show a marked annual cycle, with MT frequency reaching its lowest point in May (~18% occurrence of MT) and slowly rising to more than 40% in DJF. The average thickness of the MT also follows an annual cycle, going from less than 1 km in spring to 1.5 km in late autumn. Comparison with lidar observations show that cirrus clouds show a preference for being located close below the 1st tropopause. When the cloud top is above the 1st tropopause (7% of observations), in 20% of cases the cloud base is above it as well, resulting in a cirrus cloud "sandwiched" between the two tropopauses. Compared to the general distribution of cirrus, cross-tropopause cirrus show a higher frequency of large optical depths, while inter-t...

Noel, Vincent

2007-01-01T23:59:59.000Z

80

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

E-Print Network 3.0 - atlantic bight continental Sample Search...  

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

Ecol. Prog. Ser. Summary: STRUCTURES Generally, 2 main water masses are found in the German Bight: Continental Coastal Water... . NSW:North Sea Water; CCW: Continental Coastal...

83

Effect of electron-density gradients on propagation of radio waves in the mid-latitude trough. Master's thesis  

SciTech Connect (OSTI)

Partial contents of this thesis include: (1) Radio-wave propagation and the mid-latitude trough; (2) Ionospheric measurements; (3) Modification of time-dependent ionospheric model output with latitudinal electron-density profiles from digisonde trough depictions; (4) Ray-tracing simulations to examine ground range; and (5) Effects of three-dimensional gradients in electron density on radio-wave propagation in the trough region. Data is tabulated for geophysical conditions, solar activity level, geomagnetic activity level, conditions for vertical ray refraction to surface, and ray-tracing fixed-input conditions.

Citrone, P.J.

1991-01-01T23:59:59.000Z

84

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

85

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

86

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

87

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

88

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

89

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

90

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

91

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

92

Buoyancy of the continental upper mantle Robyn K. Kelly  

E-Print Network [OSTI]

Buoyancy of the continental upper mantle Robyn K. Kelly Department of Geology and Geophysics, MIT). Received 21 June 2002; Revised 11 October 2002; Accepted 15 October 2002; Published 18 February 2003. Kelly

93

Geotechnical characterization of sediments from Hydrate Ridge, Cascadia Continental Margin  

E-Print Network [OSTI]

Eight whole core sediment samples were obtained from ODP Site 1244, Hydrate Ridge, Cascadia Continental Margin with the goal of understanding the stress history, consolidation behavior and strength characteristics of the ...

Tan, Brian B. (Brian Bautista), 1979-

2004-01-01T23:59:59.000Z

94

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

95

Date: 30 Octobre 2014........ PAGE 1 OF 2 CONFIDENTIEL CONTINENTAL Automotive S.A.  

E-Print Network [OSTI]

Date: 30 Octobre 2014........ PAGE 1 OF 2 CONFIDENTIEL CONTINENTAL Automotive S.A. Proposition de 2015 Rémunération : 800 par mois (montant brut mensuel) Lieu: Continental Automotive France, 1 avenue.daurenjou@continental-corporation.com #12;Date: 30 Octobre 2014........ PAGE 2 OF 2 CONFIDENTIEL CONTINENTAL Automotive S.A. Internship

Dobigeon, Nicolas

96

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

97

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

98

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

99

On the connection between continental-scale land surface processes and the tropical climate in a coupled ocean-atmosphere-land system  

E-Print Network [OSTI]

the remote response to the convective heating in Africa, weand remote regions. The convective heating anomalies

Ma, H-Y; Mechoso, CR; Xue, Y; Xiao, H; Neelin, JD; Ji, X

2013-01-01T23:59:59.000Z

100

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

102

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

103

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

104

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

105

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

106

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.

107

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

108

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

109

Large-Eddy Observation of Post-Cold-Frontal Continental Stratocumulus  

E-Print Network [OSTI]

More studies on the dynamics of marine stratus and stratocumulus clouds have been performed than comparable studies on continental stratocumulus. Therefore, to increase the number of observations of continental stratocumulus ...

Mechem, David B.; Kogan, Yefim L.; Schultz, David M.

2010-10-01T23:59:59.000Z

110

PROGRAM OVERVIEW Australia is the size of continental  

E-Print Network [OSTI]

PROGRAM OVERVIEW Australia is the size of continental USA with about 1/15 of the population. It is the fourth most urban country and yet most Americans know Australia as "outback" and rural country. In a wet year, Australia is dry. Australia exports natural resources. It is "bordered" by the fourth most

Liskiewicz, Maciej

111

Intercomparison and validation of continental water level products derived  

E-Print Network [OSTI]

Abstract. Satellite radar altimeter measurements of lake and reservoir water levels complement in situIntercomparison and validation of continental water level products derived from satellite radar water level products derived from satellite radar altimetry Martina Ricko,a Charon M. Birkett,b James A

Paris-Sud XI, Université de

112

Continental Breakfast $10 Selection of Assorted Bottled Fruit Juices  

E-Print Network [OSTI]

#12;Continental Breakfast $10 Selection of Assorted Bottled Fruit Juices Seasonal Sliced Fresh Fruit Assortment of Freshly Baked Pastries Fresh Brewed Starbucks Coffee, Decaffeinated & Assorted Tazo Teas The American Breakfast Buffet $16 (Minimum of 15 guests) Selection of Assorted Bottled Fruit

Massachusetts at Lowell, University of

113

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

114

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

115

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

116

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

117

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

118

InterContinental Hotels Group | Open Energy Information  

Open Energy Info (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 CenterFranconia, Virginia: Energy Resources Jump to:46 - 429 Throttled (bot load) ErrorEnergyInnovationInterContinental Hotels Group Jump

119

On the connection between continental-scale land surface processes and the tropical climate in a coupled ocean-atmosphere-land system  

SciTech Connect (OSTI)

The impact of global tropical climate to perturbations in land surface processes (LSP) are evaluated using perturbations given by different LSP representations of continental-scale in a global climate model that includes atmosphere-ocean interactions. One representation is a simple land scheme, which specifies climatological albedos and soil moisture availability. The other representation is the more comprehensive Simplified Simple Biosphere Model, which allows for interactive soil moisture and vegetation biophysical processes. The results demonstrate that LSP processes such as interactive soil moisture and vegetation biophysical processes have strong impacts on the seasonal mean states and seasonal cycles of global precipitation, clouds, and surface air temperature. The impact is especially significant over the tropical Pacific. To explore the mechanisms for such impact, different LSP representations are confined to selected continental-scale regions where strong interactions of climate-vegetation biophysical processes are present. We find that the largest impact is mainly from LSP perturbations over the tropical African continent. The impact is through anomalous convective heating in tropical Africa due to changes in the surface heat fluxes, which in turn affect basinwide teleconnections in the Pacific through equatorial wave dynamics. The modifications in the equatorial Pacific climate are further enhanced by strong air-sea coupling between surface wind stress and upwelling, as well as effect of ocean memory. Our results further suggest that correct representations of land surface processes, land use change and the associated changes in the deep convection over tropical Africa are crucial to reducing the uncertainty when performing future climate projections under different climate change scenarios.

Ma, Hsi-Yen; Mechoso, C. R.; Xue, Yongkang; Xiao, Heng; Neelin, David; Ji, Xuan

2013-11-15T23:59:59.000Z

120

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

122

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

123

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

124

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

125

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.

126

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

127

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

128

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

129

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

130

The staircase structure of the Southern Brazilian Continental Shelf  

E-Print Network [OSTI]

We show some evidences that the Southeastern Brazilian Continental Shelf (SBCS) has a devil's staircase structure, with a sequence of scarps and terraces with widths that obey fractal formation rules. Since the formation of these features are linked with the sea level variations, we say that the sea level changes in an organized pulsating way. Although the proposed approach was applied in a particular region of the Earth, it is suitable to be applied in an integrated way to other Shelves around the world, since the analyzes favor the revelation of the global sea level variations.

M. S. Baptista; L. A. Conti

2008-10-24T23:59:59.000Z

131

Continental Divide El Coop Inc | Open Energy Information  

Open Energy Info (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 Office of InspectorConcentrating Solar Power Basics (The following text is derivedCoReturn toContinental BiofuelsDivide

132

E-Print Network 3.0 - adjacent continental margin Sample Search...  

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

adjacent to the margin. The lack of these features is also characteristic of modern transform margins... -early Paleozoic southern Lau- rentian continental ... Source: Huerta,...

133

E-Print Network 3.0 - atlantic outer continental Sample Search...  

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

<< < 1 2 3 4 5 > >> 1 Nepheloid layer distribution in the Benguela upwelling area offshore Namibia. Summary: of nepheloid layers across the outer shelf and upper continental...

134

E-Print Network 3.0 - adjacent continental shelf Sample Search...  

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

Sciences and Ecology 4 Shelf sedimentation on a tectonically active margin: A modern sediment budget for Poverty continental shelf, New Zealand Summary: of the sediment carried by...

135

E-Print Network 3.0 - atlantic continental shelf Sample Search...  

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

; Geosciences 48 The role of marsh-dominated heterotrophic continental margins in transport of CO2 between the atmosphere, the land-sea interface and Summary: : General:...

136

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

137

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

138

Extreme lithium isotopic fractionation during continental weathering revealed in saprolites from South Carolina  

E-Print Network [OSTI]

Extreme lithium isotopic fractionation during continental weathering revealed in saprolites from in revised form 6 July 2004 Abstract The lithium concentration and isotopic composition of two saprolites the behavior of lithium isotopes during continental weathering. Both saprolites show a general trend

Rudnick, Roberta L.

139

Assessing the wind field over the continental shelf as a resource for electric power  

E-Print Network [OSTI]

for the comparison period) that the near-coast phase advantage is obviated. We also find more consistent wind powerAssessing the wind field over the continental shelf as a resource for electric power by Richard W. Garvine1,2 and Willett Kempton1,3,4 ABSTRACT To assess the wind power resources of a large continental

Firestone, Jeremy

140

The Continental Margin is a Key Source of Iron to the HNLC North Pacific Ocean  

E-Print Network [OSTI]

The Continental Margin is a Key Source of Iron to the HNLC North Pacific Ocean Phoebe J. Lam1 concentrations in the upper 500m of the Western Subarctic Pacific, an iron-limited High Nutrient Low Chlorophyll a key source of bioavailable Fe to the HNLC North Pacific. Keywords: iron, continental margin, HNLC 1

Note: This page contains sample records for the topic "midlatitude continental convective" 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

Continental insulation, mantle cooling, and the surface area of oceans and continents  

E-Print Network [OSTI]

Continental insulation, mantle cooling, and the surface area of oceans and continents A. Lenardica May 2005 Abstract It is generally assumed that continents, acting as thermal insulation above. The theory predicts that parameter regimes exist for which increased continental insulation has no effect

Manga, Michael

142

Mid-Pliocene sea level and continental ice volume based on coupled benthic Mg/Ca  

E-Print Network [OSTI]

by rising sea level caused by the melting of alpine glaciers and small ice caps and portionsMid-Pliocene sea level and continental ice volume based on coupled benthic Mg/Ca palaeotemperatures composition of seawater, and estimate continental ice volume and sea-level variability during the Mid

143

Modeling suggests that oblique extension facilitates rifting and continental break-up  

E-Print Network [OSTI]

Modeling suggests that oblique extension facilitates rifting and continental break-up Sascha Brune; accepted 5 June 2012; published 2 August 2012. [1] In many cases the initial stage of continental break-up was and is associated with oblique rifting. That includes break-up in the Southern and Equatorial Atlantic, separation

Kaus, Boris

144

South Atlantic margins of Africa. page 1 South Atlantic continental margins of Africa  

E-Print Network [OSTI]

South Atlantic margins of Africa. page 1 South Atlantic continental margins of Africa: a comparison The South Atlantic continental passive margins of Africa comprise the major depocentres on the African plate of the tectonic vs climate interplay on the evolution of equatorial west Africa and SW Africa margins Michel

Paris-Sud XI, Université de

145

Surficial sediments of the continental rise and slope, Niger Delta, West Africa: properties and geology  

E-Print Network [OSTI]

useful, however sparse data on the region. Using a suite of piston cores from the lower continental slope and continental rise, this study set out to describe, illustrate, and analyze the surficial sediments of that region. With the aid of previous...

Kobilka, David William

2012-06-07T23:59:59.000Z

146

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

147

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"

148

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

149

Global Evaluation of the ISBA-TRIP Continental Hydrological System. Part I: Comparison to GRACE Terrestrial Water Storage Estimates  

E-Print Network [OSTI]

In earth system models, the partitioning of precipitation among the variations of continental water storage climate system sim- ulated by earth system models (ESMs). The continental freshwater reservoirs represent

Ribes, Aurélien

150

Potential alternative energy technologies on the Outer Continental Shelf.  

SciTech Connect (OSTI)

This technical memorandum (TM) describes the technology requirements for three alternative energy technologies for which pilot and/or commercial projects on the U.S. Outer Continental Shelf (OCS) are likely to be proposed within the next five to seven years. For each of the alternative technologies--wind, wave, and ocean current--the TM first presents an overview. After each technology-specific overview, it describes the technology requirements for four development phases: site monitoring and testing, construction, operation, and decommissioning. For each phase, the report covers the following topics (where data are available): facility description, electricity generated, ocean area (surface and bottom) occupied, resource requirements, emissions and noise sources, hazardous materials stored or used, transportation requirements, and accident potential. Where appropriate, the TM distinguishes between pilot-scale (or demonstration-scale) facilities and commercial-scale facilities.

Elcock, D.; Environmental Assessment

2007-04-20T23:59:59.000Z

151

Organic geochemistry of continental margin and deep ocean sediments  

SciTech Connect (OSTI)

The objective of this research continues to be the understanding of the complex processes of fossil fuel formation and migration. DOE funded research to date has focused on case histories'' of down-hole well profiles of light hydrocarbons, pyrograms, pyrolysis-GC and -GCMS parameters, and biomarker data from wells in the Louisiana and Texas Gulf Coasts the Alaskan North Slope. In the case of the Alaskan North Slope, geological data and one-dimensional maturation modeling have been integrated in order to better constrain possible source rocks, timing, and migration routes for oil and gas generation and expulsion processes.This period, biomarker analyses and organic petrographic analyses were completed for the Ikpikpuk well. In the case of the Gulf Coast, we have obtained a one-dimensional maturation model of the Cost B-1 well in E. Cameron field of the Louisiana Gulf Coast. The completed E. Cameron data set adds to the enigma of the Gulf Coast oils found on the continental shelf of Louisiana. If significant quantities of the oil are coming from relatively organic lean Tertiary rocks, then non-conventional'' expulsion and migration mechanisms, such as gas dissolved in oil must be invoked to explain the Gulf Coast oils reservoired on the Louisiana continental shelf. We are designing and starting to assemble a hydrous pyrolysis apparatus to follow, the laboratory, rates of generation and expulsion of sediment gases. Initiation of some new research to examine {delta}{sup 13}C of individual compounds from pyrolysis is also described. We are beginning to examine both the laboratory and field data from the Gulf Coast in the context of a Global Basin Research Network (GBRN). The purpose is to better understand subsurface fluid flow processes over geologic time in sedimentary basins and their relation to resource accumulation (i.e., petroleum and metal ores). 58 refs.

Whelan, J.K.; Hunt, J.M.; Eglinton, T.; Dickinson, P.; Johnson, C.; Buxton, L.; Tarafa, M.E.

1990-08-01T23:59:59.000Z

152

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...

153

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

154

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

155

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

156

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

157

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

158

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

159

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

160

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

162

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

163

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

164

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

165

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

166

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

167

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

168

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

169

Deep observation and sampling of the earth's continental crust (DOSECC). Final report  

SciTech Connect (OSTI)

The need to validate and refine concepts regarding the structure, properties, and dynamic processes of the earth's continental crust through the use of the drill was the subject of the workshop sponsored by DOSECC, Inc. and held April 29 through May 1, 1985 in Houston, Texas and attended by more than 145 scientists. Scientific objectives and targets for a program of research drilling as part of basic studies of the continental lithosphere were discussed, with over 30 scientific proposals presented. Individual drilling proposals were grouped under several themes; basement structures and deep continental basins, active fault zones, thermal regimes and fossil mineralized hydrothermal/magma systems.

Not Available

1985-05-01T23:59:59.000Z

170

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

171

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

172

Seismic investigation of the transition from continental to oceanic subduction along the western Hellenic Subduction Zone  

E-Print Network [OSTI]

The western Hellenic subduction zone (WHSZ) exhibits well-documented along-strike variations in lithosphere density (i.e., oceanic versus continental), subduction rates, and overriding plate extension. Differences in slab ...

Pearce, Frederick Douglas

173

Rates of tectonic and magmatic processes in the North Cascades continental magmatic arc  

E-Print Network [OSTI]

Continental magmatic arcs are among the most dynamic. geologic systems, and documentation of the magmatic, thermal, and tectonic evolution of arcs is essential for understanding the processes of magma generation, ascent ...

Matzel, Jennifer E. Piontek, 1973-

2004-01-01T23:59:59.000Z

174

The regional geothermal heat flow regime of the north-central Gulf of Mexico continental slope.  

E-Print Network [OSTI]

??Eighty-eight oil and gas wells located in the Texas-Louisiana continental slope were analyzed to obtain heat flow and geothermal gradient values. Present-day geothermal heat flow… (more)

Jones, Michael S

2003-01-01T23:59:59.000Z

175

Interpretation of side-scan sonar images from hydrocarbon seep areas of the Louisiana continental slope  

E-Print Network [OSTI]

Side-scan sonar images from the Louisiana continental slope were examined to study hydrocarbon seepage and related surficial geologic seafloor features. Three study areas are located in the Green Canyon area and the Garden Bank area. Hydrocarbon...

Hou, Rusheng

2001-01-01T23:59:59.000Z

176

Electrical conductivity of continental lithospheric mantle from integrated geophysical and petrological modeling  

E-Print Network [OSTI]

Electrical conductivity of continental lithospheric mantle from integrated geophysical; published 11 October 2011. [1] The electrical conductivity of mantle minerals is highly sensitive, and compositional variations. The bulk electrical conductivity model has been integrated into the software package

Jones, Alan G.

177

Clay mineralogy and its effect on physical properties in the Gulf of Mexico northwestern continental slope  

E-Print Network [OSTI]

The clay mineral composition of sediments deposited in the last six oxygen isotope stages in the Gulf of Mexico continental slope was characterized. Smectite and illite were found to be the two major clay minerals of the clay fraction while...

Berti, Debora

2005-02-17T23:59:59.000Z

178

The effect of LNG on the relationship between UK and Continental Europena natural gas markets  

E-Print Network [OSTI]

the structural relationship between UK and Continental European markets. (ii) The effect of UK import capacity extensions since 2005, through both pipeline and LNG regasification capacity, on this long-term relationship will be analyzed. The results suggest...

Koenig, Philipp

2012-12-10T23:59:59.000Z

179

Remote sensing of submerged objects and geomorphology in continental shelf waters with acoustic waveguide scattering  

E-Print Network [OSTI]

The long range imaging of submerged objects, seafloor and sub-seafloor geomorphology in continental shelf waters using an active sonar system is explored experimentally and theoretically. A unified model for 3-D object ...

Ratilal, Purnima, 1971-

2002-01-01T23:59:59.000Z

180

Surface sediment analysis of five carbonate banks on the Texas continental shelf  

E-Print Network [OSTI]

SURFACE SEDIMENT ANALYSIS OF FIVE CARBONATE BANKS ON THE TEXAS CONTINENTAL SHELF A Thesis by Susanne E. Cunningham Submitted to the Graduate College of Texas AcM University In partial fulfillment of the requirement for the degree of MASTER... Member Member December 1977 ABSTRACT SURFACE SEDIMENT ANALYSIS OF FIVE CARBONATE BANKS ON THE TEXAS CONTINENTAL SHELF (December 1977) Susanne E. Cunningham, B, S. , Indiana University Chairman of Advisory Committee: Dr. William Bryant The five...

Cunningham, Susanne E

1977-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "midlatitude continental convective" 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

Origin and distribution of sand types, northeastern U.S. Atlantic continental shelf  

E-Print Network [OSTI]

. 28 Map of the northeastern U. S. Atlantic continental margin showing locations of samples used in this study. 31 Plot of relative entropy values for harmonics 2 through 24 for samples from the northeastern U. S. Atlantic continental shelf. 36... Shape frequency distributions for harmonics 2, 19, 21, and 23 of the three grain shape types. . . . . . . . . . . . . . . . 37 SEM photographs of Type 1 fine quartz sands (coastal plain-derived). SEM photographs of Type 2 fine quartz sands (glacial...

Leschak, Pamela

1985-01-01T23:59:59.000Z

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

Structure of continental rifts: Role of older features and magmatism  

SciTech Connect (OSTI)

Recent geological and geophysical studies in several continental rifts have begun to shed light on the details of the processes which govern the structural evolution of these important exploration targets. In Kenya and Tanzania, the classic East African rift has been the object of several investigations which reveal that its location follows the boundary (suture ) between the Tanzanian craton (Archean) and Mozambiquan belt (Proterozoic), The Baikal rift also follows a similar boundary, and the Mid-continent rift of North America appears to do the same. Rifts themselves often act as zones of weakness which are reactivated by younger tectonic regimes. The classic North American example of this effect is the Eocambrian Southern Oklahoma aulacogen which was deformed to create the Anadarko basin and Wichita uplift in the late Paleozoic. The Central basin platform has a similar history although the original rift formed at [approximately]1,100Ma. Integration of geophysical data with petrologic and geochemical data from several rift zones has also provided a new picture of the nature and extent of magmatic modification of the crust. An interesting contradiction is that Phanerozoic rifts, except the Afar region, show little evidence for major magmatic modification of the crust whereas, at least in North America, many Precambrian rifts are associated with very large mafic bodies in the crust. The Kenya rift displays evidence for modification of the lower crust in a two-phase magmatic history, but upper crustal magmatic features are limited to local intrusions associated with volcanoes. In this rift, complex basement structure plays a much more important role than previously realized, and the geophysical signatures of basement structure and magmatism are easy to confuse. If this is also the case in other rifts, additional rift basins remain to be discovered.

Keller, G.R. (Univ. of Texas, El Paso, TX (United States))

1996-01-01T23:59:59.000Z

186

Structure of continental rifts: Role of older features and magmatism  

SciTech Connect (OSTI)

Recent geological and geophysical studies in several continental rifts have begun to shed light on the details of the processes which govern the structural evolution of these important exploration targets. In Kenya and Tanzania, the classic East African rift has been the object of several investigations which reveal that its location follows the boundary (suture ?) between the Tanzanian craton (Archean) and Mozambiquan belt (Proterozoic), The Baikal rift also follows a similar boundary, and the Mid-continent rift of North America appears to do the same. Rifts themselves often act as zones of weakness which are reactivated by younger tectonic regimes. The classic North American example of this effect is the Eocambrian Southern Oklahoma aulacogen which was deformed to create the Anadarko basin and Wichita uplift in the late Paleozoic. The Central basin platform has a similar history although the original rift formed at {approximately}1,100Ma. Integration of geophysical data with petrologic and geochemical data from several rift zones has also provided a new picture of the nature and extent of magmatic modification of the crust. An interesting contradiction is that Phanerozoic rifts, except the Afar region, show little evidence for major magmatic modification of the crust whereas, at least in North America, many Precambrian rifts are associated with very large mafic bodies in the crust. The Kenya rift displays evidence for modification of the lower crust in a two-phase magmatic history, but upper crustal magmatic features are limited to local intrusions associated with volcanoes. In this rift, complex basement structure plays a much more important role than previously realized, and the geophysical signatures of basement structure and magmatism are easy to confuse. If this is also the case in other rifts, additional rift basins remain to be discovered.

Keller, G.R. [Univ. of Texas, El Paso, TX (United States)

1996-12-31T23:59:59.000Z

187

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

188

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

189

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

190

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

191

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

192

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.

193

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

194

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

195

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

196

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.

197

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

198

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

199

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

200

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

202

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

203

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

204

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

205

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

206

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.

207

The continental margin is a key source of iron to the HNLC North Pacific Ocean  

SciTech Connect (OSTI)

Here we show that labile particulate iron and manganese concentrations in the upper 500m of the Western Subarctic Pacific, an iron-limited High Nutrient Low Chlorophyll (HNLC) region, have prominent subsurface maxima between 100-200 m, reaching 3 nM and 600 pM, respectively. The subsurface concentration maxima in particulate Fe are characterized by a more reduced oxidation state, suggesting a source from primary volcagenic minerals such as from the Kuril/Kamchatka margin. The systematics of these profiles suggest a consistently strong lateral advection of labile Mn and Fe from redox-mobilized labile sources at the continental shelf supplemented by a more variable source of Fe from the upper continental slope. This subsurface supply of iron from the continental margin is shallow enough to be accessible to the surface through winter upwelling and vertical mixing, and is likely a key source of bioavailable Fe to the HNLC North Pacific.

Lam, P.J.; Bishop, J.K.B

2008-01-15T23:59:59.000Z

208

Littoral processes and sediments of the inner continental shelf of the southern bay of Campeche  

E-Print Network [OSTI]

LITTORAL PROCESSES AND SEDIMEN' S OF THE INNER CONTINENTAL SHELF OF THE SOUTHERN BAY OF CAMPECHE A Thesis By Amado Yanez Submitted to the Graduate College of the Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1968 Major Subject: Geological Oceanograpny LITTOBAL PPOCESS ~ S AMD SEDIMENTS OF THE INNER CONTINENTAL SHELF OF THE SOUTHERN BAY OF CK41PL'CHE A Thesis Amado Yanez Approved as to style and content by (Chairman o f Committee...

Yanez, Amado

1968-01-01T23:59:59.000Z

209

On the transfer of atmospheric energy from the Gulf of Mexico to the continental United States  

E-Print Network [OSTI]

ON THE TRANSFER OF ATMOSPHERIC ENERGY FROM THE GULP OF MEXICO TO THE CONTINENTAL UNITED STATES A Thesis RICHARD WILLIAM KNIGHT Submitted to the Graduate College of Texas AkM University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE Deoember 1972 Ma)or Sub)ect: Meteorology ON THE TRANSFER OF ATMOSPHERIC ENERGY FROM THE GULF OF MEXICO TO THE CONTINENTAL UNITED STATES A Thesis RICHARD WILLIAM KNIGHT Approved as to style and content by: Chairman of ommittee...

Knight, Richard William

2012-06-07T23:59:59.000Z

210

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

211

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

212

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

213

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

214

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

215

Bulletin of the Seismological Society of America, 90, 2, pp. 425449, April 2000 Earthquake Locations in the Inner Continental Borderland,  

E-Print Network [OSTI]

Locations in the Inner Continental Borderland, Offshore Southern California by Luciana Astiz and Peter M. Shearer Abstract The inner Continental Borderland region, offshore southern California, is tectonically in this area, we apply new location methods to 4312 offshore seismic events that occurred between 1981 and 1997

Shearer, Peter

216

South Atlantic continental margins of Africa: A comparison of the tectonic vs climate interplay on the evolution  

E-Print Network [OSTI]

South Atlantic continental margins of Africa: A comparison of the tectonic vs climate interplay on the evolution of equatorial west Africa and SW Africa margins Michel Se´ranne *, Zahie Anka UMR 5573 Dynamique February 2005; accepted 18 July 2005 Abstract Africa displays a variety of continental margin structures

Demouchy, Sylvie

217

Resonant Generation of Internal Waves on a Model Continental Slope H. P. Zhang, B. King, and Harry L. Swinney  

E-Print Network [OSTI]

Resonant Generation of Internal Waves on a Model Continental Slope H. P. Zhang, B. King, and Harry wave generation in a laboratory model of oscillating tidal flow on a continental margin. Waves are found to be generated only in a near-critical region where the slope of the bottom topography matches

Texas at Austin. University of

218

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

219

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

220

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

Continental Shelf Research 26 (2006) 1524 Geochemical compositions of river and shelf sediments in the  

E-Print Network [OSTI]

Continental Shelf Research 26 (2006) 15­24 Geochemical compositions of river and shelf sediments in the Yellow Sea: Grain-size normalization and sediment provenance D.I. Lima,�, H.S. Jungb , J.Y. Choic , S 14 November 2005 Abstract The geochemistry of sediment samples from Korean and Chinese rivers

Yang, Shouye

222

Lithium isotopic composition and concentration of the deep continental crust Fang-Zhen Teng a,  

E-Print Network [OSTI]

Lithium isotopic composition and concentration of the deep continental crust Fang-Zhen Teng a April 2008 Accepted 5 June 2008 Editor: B. Bourdon Keywords: Lithium Isotope fractionation Deep. Lithium concentrations of granulite xenoliths also vary widely (0.5 to 21 ppm) and are, on average, lower

Mcdonough, William F.

223

Recent glacially influenced sedimentary processes on the East Greenland continental slope and deep Greenland Basin  

E-Print Network [OSTI]

Recent glacially influenced sedimentary processes on the East Greenland continental slope and deep Greenland Basin Marga García a,*, Julian A. Dowdeswell a , Gemma Ercilla b , Martin Jakobsson c a Scott June 2012 Available online xxx Keywords: Greenland Basin Glacially influenced sedimentary processes

Jakobsson, Martin

224

Festival del Sur-Encuentro Teatral Tres Continentes: Un festival consolidado  

E-Print Network [OSTI]

latinoamericana por vocación, pues sus habitantes siempre han emparentado su destino al de Latinoamérica y su mirada ha ido dirigida al Oeste y nunca al continente europeo. Durante las siete ediciones del Festival del Sur casi doscientos grupos han pasado por...

Má rquez Montes, Carmen

1995-10-01T23:59:59.000Z

225

Grazing intensity impacts soil carbon and nitrogen storage of continental steppe  

E-Print Network [OSTI]

Grazing intensity impacts soil carbon and nitrogen storage of continental steppe N. P. HE,1,2 Y. H. Chen, Q. M. Pan, G. M. Zhang, and X. G. Han. 2011. Grazing intensity impacts soil carbon and nitrogen 100049 China Abstract. Recent studies have underscored the importance of grasslands as potential carbon

Yu, Qiang

226

A remote sensing observatory for hydrologic sciences: A genesis for scaling to continental hydrology  

E-Print Network [OSTI]

A remote sensing observatory for hydrologic sciences: A genesis for scaling to continental hydrology Witold F. Krajewski,1 Martha C. Anderson,2 William E. Eichinger,1 Dara Entekhabi,3 Brian K arise primarily from an inadequate understanding of the hydrological cycle: on land, in oceans

Katul, Gabriel

227

Ice sheet limits in Norway and on the Norwegian continental shelf Jan Mangerud  

E-Print Network [OSTI]

Ice sheet limits in Norway and on the Norwegian continental shelf Jan Mangerud University of Bergen, Department of Geology, Allégt. 41, N-5007 Bergen, Norway Jan.Mangerud@geol.uib.no Introduction Ice sheets the author will briefly review present knowledge of the glacial history of Norway. The recon- struction

Ingólfsson, �lafur

228

Original article On the Late Miocene continentalization of the Guadix Basin: More evidence for a  

E-Print Network [OSTI]

connection existed through the Guadix-Baza, Fortuna and Lorca basins during the Messinian (Mu¨ ller and Hsu of the sedimentary fill of the Fortuna (Garce´s et al., 1998, 2001) and Lorca Basins (Krijgsman et al., 2000). These studies revealed that the marine-continental transition in the Fortuna and Lorca basins occurred

Utrecht, Universiteit

229

Orbital and CO2 forcing of late Paleozoic continental ice sheets Daniel E. Horton,1  

E-Print Network [OSTI]

) produce large changes in late Paleozoic ice volume ($1.3 � 108 km3 ) and sea level ($20 to 245 m). Between cold summer orbit, but still produces significant ice volumes ($8­12 � 107 km3 ). Our results highlightOrbital and CO2 forcing of late Paleozoic continental ice sheets Daniel E. Horton,1 Christopher J

Poulsen, Chris J.

230

Atlantic update, July 1986--June 1990: Outer Continental Shelf oil and gas activities  

SciTech Connect (OSTI)

This report describes outer continental shelf oil and gas activities in the Atlantic Region. This edition of the Atlantic Update includes an overview of the Mid-Atlantic Planning Area and a summary of the Manteo Prospect off-shore North Carolina. 6 figs., 8 tabs.

Karpas, R.M.; Gould, G.J.

1990-10-01T23:59:59.000Z

231

Statistical analysis of 4-year observations of aerosol sizes in a semi-rural continental environment  

E-Print Network [OSTI]

Statistical analysis of 4-year observations of aerosol sizes in a semi-rural continental. Introduction Formation of new aerosol particles via gas-to-particle conver- sion is an important process, which to understanding how new particle formation (NPF) processes lead to formation of cloud condensation nuclei (CCN

Lee, Shan-Hu

232

Continental energy security: Energy security in the North American context1  

E-Print Network [OSTI]

, commissioned reports, and signed legislation in an effort to stem crude oil imports and improve energy securityERG/201101 Continental energy security: Energy security in the North American context1 Larry Hughes, Canada 24 January 2011 1 A textbox for the Global Energy Assessment's Knowledge Module 5: Energy Security

Hughes, Larry

233

The epibenthic megafauna of the northern Gulf of Mexico continental slope  

E-Print Network [OSTI]

The epibenthic megafauna of the continental slope and abyssal plain of the northern Gulf of Mexico have been investigated using multi-shot bottom photography. A total of 10,388 photographs were analyzed from 100 sites encompassing a total area...

Ziegler, Matthew Peek

2002-01-01T23:59:59.000Z

234

Inversion tectonics during continental rifting: The Turkana Cenozoic rifted zone, northern Kenya  

E-Print Network [OSTI]

Inversion tectonics during continental rifting: The Turkana Cenozoic rifted zone, northern Kenya B of inverted deformation within Miocene-Recent basins of the Turkana rift (northern Kenya) in the eastern: The Turkana Cenozoic rifted zone, northern Kenya, Tectonics, 24, TC2002, doi:10.1029/2004TC001637. 1

Brest, Université de

235

Continental Shelf Research 21 (2001) 587606 Nutrient enrichment off Port Stephens  

E-Print Network [OSTI]

Continental Shelf Research 21 (2001) 587­606 Nutrient enrichment off Port Stephens: the role of the dinoflagellate Noctiluca scintillans occurred off Port Stephens, on the New South Wales (NSW) central coast water into the euphotic zone off Port Stephens. To this end, a regional model of the NSW coast

Oke, Peter

236

Oil and Gas CDT Gas hydrate distribution on tectonically active continental  

E-Print Network [OSTI]

Oil and Gas CDT Gas hydrate distribution on tectonically active continental margins: Impact on gas. Gregory F. Moore, University of Hawaii (USA) http://www.soest.hawaii.edu/moore/ Key Words Gas Hydrates, Faults, Fluid Flow, gas prospectivity Overview Fig. 1. Research on gas hydrates is often undertaken

Henderson, Gideon

237

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

238

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

239

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,...

240

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

ARM - MC3E Planning - Data Plots  

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) by Microtops Atmospheric OpticalExperimentgovField CampaignsMidlatitude Continental Convective

242

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

243

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

244

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

245

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

246

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

247

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

248

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:

249

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

250

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

251

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

252

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

253

The shallow geologic features of the upper continental slope, northern Gulf of Mexico  

E-Print Network [OSTI]

-slope basin directly below the continental shelf break. The basin was formed by the salt's diapiric action in forming a slightly elongate dome that blocked a small trough or canyon. It is possible that the core of ihe dome is salt, as is indicated... Deposits. . . Mud Flows. Sediment Creep Mobile Formation Structures. Peripheral and Arcuate Shelf Edge Slumps. . Normal Faults. Growth Faults Monoclinal Folds. Diapirism and Related Structures. Mounds and Intrusives. . . SALT DIAPIRISM...

Buck, Arvo Viktor

1981-01-01T23:59:59.000Z

254

Geomorphic interpretation of the bathymetry of the Bay of Campeche seaward of the continental shelf  

E-Print Network [OSTI]

, is it covers a large seotor of the Gulf~ its study is involved in a number of larger& particularly interesting problems that are ourrently attracting the attention of geologists, Paul Weaver (1950) says about the Oulfc "'Ihe two theories ~ one... enough evidcnoe fram hydrographic surveys and. bottom samples so that he can recommend local areas for test of the two theories~ he will speed the evaluat1on and operating program (of petro- leum development) of the continental shelf with maximum...

Creager, Joe S

2012-06-07T23:59:59.000Z

255

Transport and transfer rates in the waters of the continental shelf. Annual report  

SciTech Connect (OSTI)

The goal of govern project is to understand and quantify the processes that the transport and dispersal of energy-related pollutants introduced to the waters of the continental shelf and slope. The report is divided into sections dealing with processes associated with suspended solids; processes associated with sediments sinks for radionuclides and other pollutants; and spreading of water characteristics and species in solution. (ACR)

Biscaye, P.E.

1980-09-01T23:59:59.000Z

256

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

257

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

258

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

259

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

260

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

262

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.

263

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.

264

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

265

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

266

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

267

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

268

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

269

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

270

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

E-Print Network [OSTI]

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

Goud, Margaret R

1987-01-01T23:59:59.000Z

271

Cross-shelf circulation and momentum and heat balances over the inner continental shelf near Martha's Vineyard, Massachusetts  

E-Print Network [OSTI]

The water circulation and evolution of water temperature over the inner continental shelf are investigated using observations of water velocity, temperature, density, and bottom pressure; surface gravity waves; wind stress; ...

Fewings, Melanie Rinn

2007-01-01T23:59:59.000Z

272

Wintertime pytoplankton bloom in the Subarctic Pacific supportedby continental margin iron  

SciTech Connect (OSTI)

Heightened biological activity was observed in February 1996in the high-nutrient low-chlorophyll (HNLC) subarctic North PacificOcean, a region that is thought to beiron-limited. Here we provideevidence supporting the hypothesis that Ocean Station Papa (OSP) in thesubarctic Pacific received a lateral supply of particulate iron from thecontinental margin off the Aleutian Islands in the winter, coincidentwith the observed biological bloom. Synchrotron X-ray analysis was usedto describe the physical form, chemistry, and depth distributions of ironin size fractionated particulate matter samples. The analysis revealsthat discrete micron-sized iron-rich hotspots are ubiquitous in the upper200m at OSP, more than 900km from the closest coast. The specifics of thechemistry and depth profiles of the Fe hot spots trace them to thecontinental margins. We thus hypothesize that iron hotspots are a markerfor the delivery of iron from the continental margin. We confirm thedelivery of continental margin iron to the open ocean using an oceangeneral circulation model with an iron-like tracer source at thecontinental margin. We suggest that iron from the continental marginstimulated a wintertime phytoplankton bloom, partially relieving the HNLCcondition.

Lam, Phoebe J.; Bishop, James K.B.; Henning, Cara C.; Marcus,Matthew A.; Waychunas, Glenn A.; Fung, Inez

2004-06-08T23:59:59.000Z

273

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

274

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"

275

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

276

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.

277

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

278

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

279

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

280

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

282

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

283

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

284

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

285

Uranium-series comminution ages of continental sediments: Case study of a Pleistocene alluvial fan  

SciTech Connect (OSTI)

Obtaining quantitative information about the timescales associated with sediment transport, storage, and deposition in continental settings is important but challenging. The uranium-series comminution age method potentially provides a universal approach for direct dating of Quaternary detrital sediments, and can also provide estimates of the sediment transport and storage timescales. (The word"comminution" means"to reduce to powder," reflecting the start of the comminution age clock as reduction of lithic parent material below a critical grain size threshold of ~;;50 mu m.) To test the comminution age method as a means to date continental sediments, we applied the method to drill-core samples of the glacially-derived Kings River Fan alluvial deposits in central California. Sediments from the 45 m core have independently-estimated depositional ages of up to ~;;800 ka, based on paleomagnetism and correlations to nearby dated sediments. We characterized sequentially-leached core samples (both bulk sediment and grain size separates) for U, Nd, and Sr isotopes, grain size, surface texture, and mineralogy. In accordance with the comminution age model, where 234U is partially lost from small sediment grains due to alpha recoil, we found that (234U/238U) activity ratios generally decrease with age, depth, and specific surface area, with depletions of up to 9percent relative to radioactive equilibrium. The resulting calculated comminution ages are reasonable, although they do not exactly match age estimates from previous studies and also depend on assumptions about 234U loss rates. The results indicate that the method may be a significant addition to the sparse set of available tools for dating detrital continental sediments, following further refinement. Improving the accuracy of the method requires more advanced models or measurements for both the recoil loss factor fa and weathering effects. We discuss several independent methods for obtaining fa on individual samples that may be useful for future studies.

Lee, Victoria E.; DePaolo, Donald J.; Christensen, John N.

2010-04-30T23:59:59.000Z

286

E-Print Network 3.0 - andes uplift contribute Sample Search Results  

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

on South American moisture transport, convection, and precipitation Summary: Uplift South America Regional modeling Andes 1 Introduction Large, mid-latitude mountain......

287

Epibenthic invertebrates and fishes of the continental shelf of the northwestern Gulf of Mexico  

E-Print Network [OSTI]

provinces that are considered to be geologically distinct (Kennedy 1976): 1). The Gulf of Mexico Basin, 2). The northeast Gulf of Mexico, 3). The South Florida continental shelf and slope, 4). Campeche Bank, 5), The Style and format follow Contributions...V V Vill 9 15 15 19 70 72 74 APPENDIX 7. . APPENDIX 8. . APPENDIX 9. . APPENDIX 10. VITA Page 81 91 101 LIST OF FIGURES FIGURE Page Geological provinces in the Gulf of Mexico. . . Study area in the Northwestern Gulf of Mexico...

Al-Jabr, Abdulrahman Mohammad

1995-01-01T23:59:59.000Z

288

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

289

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

290

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

291

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

292

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

293

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

294

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

295

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

296

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.

297

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

298

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

299

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

300

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

302

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

303

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.

304

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

305

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

306

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

307

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

308

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

309

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

310

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

311

PII S0016-7037(99)00066-6 Fluxes of dissolved organic carbon from California continental margin sediments  

E-Print Network [OSTI]

sediments DAVID J. BURDIGE,1, * WILLIAM M. BERELSON,2 KENNETH H. COALE,3 JAMES MCMANUS,4 and KENNETH S) from marine sediments represent a poorly constrained component of the oceanic carbon cycle that may measurements of DOC fluxes from continental margin sediments (water depths ranging from 95 to 3,700 m

Burdige, David

312

NUMBER1,2005 Published by the Integrated Ocean Drilling Program with the International Continental Scientific Drilling Program  

E-Print Network [OSTI]

NUMBER1,2005 Published by the Integrated Ocean Drilling Program with the International Continental Scientific Drilling Program No.14,September2012 ScientificDrilling ISSN: 1816-8957 Exp. 333: Nankai Trough Subduction Input and Records of Slope Instability 4 Lake Drilling In Eastern Turkey 18 Exp. 326 and 332: Nan

Gilli, Adrian

313

NUMBER1,2005 Published by the Integrated Ocean Drilling Program with the International Continental Scientific Drilling Program  

E-Print Network [OSTI]

NUMBER1,2005 Published by the Integrated Ocean Drilling Program with the International Continental Scientific Drilling Program No.11,March2011 ScientificDrilling ISSN: 1816-8957 Climate and Ocean Change in the Bering Sea 4 San Andreas Fault Zone Drilling 14 Climate History from Lake El'gygytgyn, Siberia 29 World

Demouchy, Sylvie

314

Horizontal coherence of low-frequency fixed-path sound in a continental shelf region with internal-wave activity  

E-Print Network [OSTI]

Horizontal coherence of low-frequency fixed-path sound in a continental shelf region with internal-wave) populated with tidally generated long- and short-wavelength internal waves. Sound paths are 19 km and explain sound field spatial and temporal variability under these conditions. The intermittent internal-wave

315

Project EARTH-13-AH1: Isotopic studies of continental weathering -the transport of germanium in soils and plants  

E-Print Network [OSTI]

Project EARTH-13-AH1: Isotopic studies of continental weathering - the transport of germanium silicate weathering is important if we are to understand the carbon cycle 1,2 . The similarity of Ge and Si for weathering intensity3,7-9 . However, factors driving Ge behaviour in soil remain largely unknown although

Henderson, Gideon

316

Sequential extraction of iron in marine sediments from the Chilean continental Laurent Dezileau, Carmen Pizarro, Maria Angelica Rubio  

E-Print Network [OSTI]

.margeo.2007.03.006 Reference: MARGO 4032 To appear in: Marine Geology Received date: 22 September 2006 Revised the Chilean continental margin, Marine Geology (2007), doi: 10.1016/j.margeo.2007.03.006 This is a PDF file in the southeastern Pacific.22 #12;ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2 Keywords: Iron, uranium, Chile

Demouchy, Sylvie

317

Radiological effluents released from US continental tests, 1961 through 1992. Revision 1  

SciTech Connect (OSTI)

This report documents all continental tests from September 15, 1961, through September 23, 1992, from which radioactive effluents were released. The report includes both updated information previously published in the publicly available May, 1990 report, DOE/NV-317, ``Radiological Effluents Released from Announced US Continental Tests 1961 through 1988``, and effluent release information on formerly unannounced tests. General information provided for each test includes the date, time, location, type of test, sponsoring laboratory and/or agency or other sponsor, depth of burial, purpose, yield or yield range, extent of release (onsite only or offsite), and category of release (detonation-time versus post-test operations). Where a test with simultaneous detonations is listed, location, depth of burial and yield information are given for each detonation if applicable, as well as the specific source of the release. A summary of each release incident by type of release is included. For a detonation-time release, the effluent curies are expressed at R+12 hours. For a controlled releases from tunnel-tests, the effluent curies are expressed at both time of release and at R+12 hours. All other types are listed at the time of the release. In addition, a qualitative statement of the isotopes in the effluent is included for detonation-time and controlled releases and a quantitative listing is included for all other types. Offsite release information includes the cloud direction, the maximum activity detected in the air offsite, the maximum gamma exposure rate detected offsite, the maximum iodine level detected offsite, and the maximum distance radiation was detected offsite. A release summary incudes whatever other pertinent information is available for each release incident. This document includes effluent release information for 433 tests, some of which have simultaneous detonations. However, only 52 of these are designated as having offsite releases.

Schoengold, C.R.; DeMarre, M.E.; Kirkwood, E.M.

1996-08-01T23:59:59.000Z

318

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

319

Chlorine-36 in Water, Snow, and Mid-Latitude Glacial Ice of North America: Meteoric and Weapons-Tests Production in the Vicinity of the Idaho National Engineering and Environmental Laboratory, Idaho  

SciTech Connect (OSTI)

Measurements of chlorine-36 (36Cl) were made for 64 water, snow, and glacial-ice and -runoff samples to determine the meteoric and weapons-tests-produced concentrations and fluxes of this radionuclide at mid-latitudes in North America. The results will facilitate the use of 36Cl as a hydrogeologic tracer at the Idaho National Engineering and Environmental Laboratory (INEEL). This information was used to estimate meteoric and weapons-tests contributions of this nuclide to environmental inventories at and near the INEEL. The data presented in this report suggest a meteoric source 36Cl for environmental samples collected in southeastern Idaho and western Wyoming if the concentration is less than 1 x 10 7 atoms/L. Additionally, concentrations in water, snow, or glacial ice between 1 x 10 7 and 1 x 10 8 atoms/L may be indicative of a weapons-tests component from peak 36Cl production in the late 1950s. Chlorine-36 concentrations between 1 x 10 8 and 1 x 10 9 atoms/L may be representative of re-suspension of weapons-tests fallout airborne disposal of 36Cl from the INTEC, or evapotranspiration. It was concluded from the water, snow, and glacial data presented here that concentrations of 36Cl measured in environmental samples at the INEEL larger than 1 x 10 9 atoms/L can be attributed to waste-disposal practices.

L. DeWayne; J. R. Green (USGS); S. Vogt, P. Sharma (Purdue University); S. K. Frape (University of Waterloo); S. N. Davis (University of Arizona); G. L. Cottrell (USGS)

1999-01-01T23:59:59.000Z

320

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

322

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

323

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

324

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

325

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

326

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

327

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

328

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

329

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

330

Outside the Continental United States International Travel and Contagion Impact Quick Look Tool  

SciTech Connect (OSTI)

ABSTRACT This paper describes a tool that will allow public health analysts to estimate infectious disease risk at the country level as a function of different international transportation modes. The prototype focuses on a cholera epidemic originating within Latin America or the Caribbean, but it can be expanded to consider other pathogens as well. This effort leverages previous work in collaboration with the Centers for Disease Control and Prevention to develop the International Travel to Community Impact (IT-CI) model, which analyzes and assesses potential international disease outbreaks then estimates the associated impacts to U.S. communities and the nation as a whole and orient it for use Outside the Continental United States (OCONUS). For brevity, we refer to this refined model as OIT-CI. First, we developed an operationalized meta-population spatial cholera model for Latin America and the Caribbean at the secondary administrative-level boundary. Secondly, we developed a robust function of human airline critical to approximating mixing patterns in the meta- population model. In the prototype version currently presented here, OIT-CI models a cholera epidemic originating in a Latin American or Caribbean country and spreading via airline transportation routes. Disease spread is modeled at the country level using a patch model with a connectivity function based on demographic, geospatial, and human transportation data. We have also identified data to estimate the water and health-related infrastructure capabilities of each country to include this potential impact on disease transmission.

Corley, Courtney D.; Lancaster, Mary J.; Brigantic, Robert T.; Kunkel, Brenda M.; Muller, George; McKenzie, Taylor K.

2012-11-09T23:59:59.000Z

331

Maturation of Tertiary sediments in the Asian Continental Margins: A basis for hydrocarbon generation studies  

SciTech Connect (OSTI)

In the marginal areas of the Asian continent, the Paleogene and Miocene coal-bearing formations are sporadically distributed. In some areas, particularly in the sea regions, their equivalents are possibly explored for oil and gas. The basins mainly formed as tectonic depressions, and are filled with fluvial to marine clastic rocks. The formations show marked lateral variation in thickness, lithology, and sediment characteristics, which are related to the geotectonic settings of the basins at active plate margins. Remarkable accumulation of overburden and high paleogeothermal conditions, which are marked in northern Kyushu, Japan, and Thailand, influenced diagenesis. Organic and inorganic maturation studies in northern Kyushu reveal a progress of diagenesis from the inland of Kyushu toward the sea region essentially controlled by additional heat supply from the sea region during and after sedimentation. The sediments on the land surface are chiefly overmatured, and/or contain minor amounts of organic carbon. High paleogeothermal influence on Tertiary maturation is clear also in northern Thailand. The high paleotemperature conditions in these areas may be related to tectonic interaction between the oceanic and continental plates.

Miki, Takashi (Kyushu Univ., Fukuoka (Japan))

1994-07-01T23:59:59.000Z

332

Source-inherited shape characteristics of coarse quartz-silt on the northwest Gulf of Mexico continental shelf  

E-Print Network [OSTI]

shelf. The purpose was to determine the uni. que "shape-signatures" of coarse quartz-silt grains from crystalline and sedimentary source-terranes in the north- west Gulf of Mexico, and to determine the provenance and distribution of coarse...-silt on the northwest Gulf of Mexico continental shelf, Three conclusions were reached. The first is that the three source-terranes for the South Texas shelf release coarse quartz-silt grains with distinguishable shape characteristics. Crystalline rocks from...

Haines, John Beverly

1986-01-01T23:59:59.000Z

333

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

334

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

335

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.

336

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.

337

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

338

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

339

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.

340

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

342

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

343

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.

344

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

345

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

346

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

347

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

348

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

349

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

350

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

351

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.

352

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.

353

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

354

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

355

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

356

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

357

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

358

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

359

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

360

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

362

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

363

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

364

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

365

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

366

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.

367

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.

368

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

369

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

370

Selected growth and interaction characteristics of seafloor faults in the central Mississippi Canyon Offshore Continental Shelf (OCS) area, northern Gulf of Mexico  

E-Print Network [OSTI]

. Specifically, the characteristics of growth, interaction, and linkage of faults are of interest. Most of the Gulf has seen continuous clastic sediment deposition since the end of continental rifting in the middle Mesozoic. The Gulf is a tectonically quiescent...

Wegner, Scott Ashley

2006-08-16T23:59:59.000Z

371

Estimation of Hourly Solar Loads on the Surfaces of Moving Refrigerated Tractor Trailers Outfitted with Phase Change Materials (PCMs) for Several Routes across the Continental U.S.  

E-Print Network [OSTI]

The primary objective of this thesis was to calculate solar loads, wind chill temperatures on the surfaces of moving refrigerated tractor trailers outfitted with phase change materials (PCMs) for several routes across the Continental United States...

Varadarajan, Krupasagar

2011-08-31T23:59:59.000Z

372

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

373

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

374

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

375

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

376

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

377

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

378

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

379

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

380

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

382

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

383

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

384

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

385

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

386

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

387

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

388

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

389

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

390

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

391

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

392

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

393

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

394

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

395

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

396

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

397

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

398

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

399

Continental shelf processes affecting the oceanography of the South Atlantic Bight. Progress report, June 1, 1979-May 31, 1980  

SciTech Connect (OSTI)

Progress is reported on research conducted from June, 1979 to May, 1980 on various oceanographic aspects of the South Atlantic Bight. Research topics included: (1) A flashing model of Onslow Bay, North Carolina based on intrusion volumes; (2) A description of a bottom intrusion in Onslow Bay, North Carolina; (3) Detailed observations of a Gulf Stream spin-off eddy on the Georgia continental shelf; (4) Pelagic tar of Georgia and Florida; (5) A surface diaton bloom in response to eddy-forced upwelling; and (6) Hydrographic observations off Savannah and Brunswick, Georgia.

Atkinson, L P

1980-02-29T23:59:59.000Z

400

Engineering properties of shallow sediments in West Delta and South Pass Outer Continental Shelf Lease Areas, offshore Louisiana  

E-Print Network [OSTI]

ENGINEERING PROPERTIES OF SHALLOW SEDIMENTS IN WEST DELTA AND SOUTH PASS OUTER CONTINENTAL SHELF LEASE AREAS& OFFSHORE LOUISIANA A Thesis by STERLING J. HELWICK, JR. Submitted to the Graduate College of Texas A&M University in partial... by STERLING J. HELWICK, JR. Approved as to style and content by: (Chairman of C mmit e) (Head of Depart t) Member / gg&wrt r~ Fc' Qg~s/~ (Member) ( her) May 1977 44", 672 ABSTRACT Engineering Properties of Shallow Sediments in West Delta and South...

Helwick, Sterling J

1977-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "midlatitude continental convective" 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

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

402

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

403

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

404

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

405

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

406

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

407

Assssment and Mapping of the Riverine Hydrokinetic Resource in the Continental United States  

SciTech Connect (OSTI)

The U.S. Department of Energy (DOE) funded the Electric Power Research Institute and its collaborative partners, University of Alaska ? Anchorage, University of Alaska ? Fairbanks, and the National Renewable Energy Laboratory, to provide an assessment of the riverine hydrokinetic resource in the continental United States. The assessment benefited from input obtained during two workshops attended by individuals with relevant expertise and from a National Research Council panel commissioned by DOE to provide guidance to this and other concurrent, DOE-funded assessments of water based renewable energy. These sources of expertise provided valuable advice regarding data sources and assessment methodology. The assessment of the hydrokinetic resource in the 48 contiguous states is derived from spatially-explicit data contained in NHDPlus ?a GIS-based database containing river segment-specific information on discharge characteristics and channel slope. 71,398 river segments with mean annual flow greater than 1,000 cubic feet per second (cfs) mean discharge were included in the assessment. Segments with discharge less than 1,000 cfs were dropped from the assessment, as were river segments with hydroelectric dams. The results for the theoretical and technical resource in the 48 contiguous states were found to be relatively insensitive to the cutoff chosen. Raising the cutoff to 1,500 cfs had no effect on estimate of the technically recoverable resource, and the theoretical resource was reduced by 5.3%. The segment-specific theoretical resource was estimated from these data using the standard hydrological engineering equation that relates theoretical hydraulic power (Pth, Watts) to discharge (Q, m3 s-1) and hydraulic head or change in elevation (??, m) over the length of the segment, where ? is the specific weight of water (9800 N m-3): ??? = ? ? ?? For Alaska, which is not encompassed by NPDPlus, hydraulic head and discharge data were manually obtained from Idaho National Laboratory?s Virtual Hydropower Prospector, Google Earth, and U.S. Geological Survey gages. Data were manually obtained for the eleven largest rivers with average flow rates greater than 10,000 cfs and the resulting estimate of the theoretical resource was expanded to include rivers with discharge between 1,000 cfs and 10,000 cfs based upon the contribution of rivers in the latter flow class to the total estimate in the contiguous 48 states. Segment-specific theoretical resource was aggregated by major hydrologic region in the contiguous, lower 48 states and totaled 1,146 TWh/yr. The aggregate estimate of the Alaska theoretical resource is 235 TWh/yr, yielding a total theoretical resource estimate of 1,381 TWh/yr for the continental US. The technically recoverable resource in the contiguous 48 states was estimated by applying a recovery factor to the segment-specific theoretical resource estimates. The recovery factor scales the theoretical resource for a given segment to take into account assumptions such as minimum required water velocity and depth during low flow conditions, maximum device packing density, device efficiency, and flow statistics (e.g., the 5 percentile flow relative to the average flow rate). The recovery factor also takes account of ?back effects? ? feedback effects of turbine presence on hydraulic head and velocity. The recovery factor was determined over a range of flow rates and slopes using the hydraulic model, HEC-RAS. In the hydraulic modeling, presence of turbines was accounted for by adjusting the Manning coefficient. This analysis, which included 32 scenarios, led to an empirical function relating recovery factor to slope and discharge. Sixty-nine percent of NHDPlus segments included in the theoretical resource estimate for the contiguous 48 states had an estimated recovery factor of zero. For Alaska, data on river slope was not readily available; hence, the recovery factor was estimated based on the flow rate alone. Segment-specific estimates of the theoretical resource were multiplied by the corresponding recovery factor to estimate

Jacobson, Paul T. [Electric Power Research Institute; Ravens, Thomas M. [University of Alaska Anchorage; Cunningham, Keith W. [University of Alaska Fairbanks; Scott, George [National Renewable Energy Laboratory

2012-12-14T23:59:59.000Z

408

Stratigraphic and tectonic framework of a new petroleum province in Romania: North Dobrogea - Adjoining Black Sea continental shelf  

SciTech Connect (OSTI)

The authors paper provides the first publicly available synthesis of the geologic data resulting from integrated analyses of multichannel-seismic profiles and boreholes, achieved during more than 15 years of petroleum exploration in the Romanian Black Sea continental shelf overlying the eastward extension of the Alpine North Dobrogean fold belt, where a new petroleum province is being developed. A formally established lithostratigraphic sequence is introduced for the super-Triassic Mesozoic and lower Cenozoic rocks drilled in the studied area. Chronostratigraphic, seismostratigraphic, and paleoenvironmental interpretations are included. A tentative interpretation relating the depositional record in this area to the eustatic sea level history and global depositional cycles is attempted. The major building events of this segment of the Romanian Black Sea continental shelf, where different tectonic styles were superimposed, are closely linked to the geological history of both the Alpine North Dobrogean foldbelt and the Black Sea basin. Considerations about hydrocarbon source rocks and reservoir beds in the analyzed area, together with an assessment of future potential, will also be included.

Gradinaru, E.; Corneliu, D.; Dragastan, O. (Univ. of Bucharest (Romania)); Lutac, D. (Petromar Co., Bucharest (Romania))

1991-08-01T23:59:59.000Z

409

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

410

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

411

Resumen. La fosa de Cariaco, ubicada al sur del Caribe en el margen continental de Venezuela, ha sido el foco de muchos estudios de relevancia global sobre la qumica de las aguas marinas y la  

E-Print Network [OSTI]

Resumen. La fosa de Cariaco, ubicada al sur del Caribe en el margen continental de Venezuela, ha ("2004"), 161-162: 215-234 #12;216 Características de la fosa de Cariaco, Venezuela Cariaco basin on the continental margin of Venezuela, has been the focus of many marine chemistry and paleoclimatology studies

Meyers, Steven D.

412

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

413

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

414

Evaluation of Continental Precipitation in 20th-Century Climate Simulations: The Utility of Multi-Model Statistics  

SciTech Connect (OSTI)

At the request of the Intergovernmental Panel on Climate Change (IPCC), simulations of 20th-century climate have been performed recently with some 20 global coupled ocean-atmosphere models. In view of its central importance for biological and socio-economic systems, model-simulated continental precipitation is evaluated relative to three observational estimates at both global and regional scales. Many models are found to display systematic biases, deviating markedly from the observed spatial variability and amplitude/phase of the seasonal cycle. However, the point-wise ensemble mean of all the models usually shows better statistical agreement with the observations than does any single model. Deficiencies of current models that may be responsible for the simulated precipitation biases as well as possible reasons for the improved estimate afforded by the multi-model ensemble mean are discussed. Implications of these results for water-resource managers also are briefly addressed.

Phillips, T J; Gleckler, P J

2005-11-01T23:59:59.000Z

415

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

416

Lithium isotopic systematics of A-type granites and their mafic enclaves: Further constraints on the Li isotopic composition of the continental crust  

E-Print Network [OSTI]

Lithium isotopic systematics of A-type granites and their mafic enclaves: Further constraints form 6 February 2009 Accepted 15 February 2009 Editor: D.B. Dingwell Keywords: Lithium isotopes A-type granite Mafic enclave Continental crust Lithium concentrations and isotopic compositions of 39 A

Mcdonough, William F.

417

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

418

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

419

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

420

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

Note: This page contains sample records for the topic "midlatitude continental convective" from the National Library of EnergyBeta (NLEBeta).
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421

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

422

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

423

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

424

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

425

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

426

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

427

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

428

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

429

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

430

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.

431

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.

432

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

433

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

434

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.

435

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

436

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

437

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

438

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

439

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

440

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

Regulations Related to the Outer Continental Shelf Moratoria and Implications of Not Renewing the Moratoria (released in AEO2009)  

Reports and Publications (EIA)

From 1982 through 2008, Congress annually enacted appropriations riders prohibiting the Minerals Management Service (MMS) of the U.S. Department of the Interior from conducting activities related to leasing, exploration, and production of oil and natural gas on much of the federal Outer Continental Shelf (OCS). Further, a separate executive ban (originally put in place in 1990 by President George H.W. Bush and later extended by President William J. Clinton through 2012) also prohibited leasing on the OCS, with the exception of the Western Gulf of Mexico, portions of the Central and Eastern Gulf of Mexico, and Alaska. In combination, those actions prohibited drilling along the Atlantic and Pacific coasts, in the eastern Gulf of Mexico, and in portions of the central Gulf of Mexico. The Gulf of Mexico Energy Security Act of 2006 (Public Law 109-432) imposed yet a third ban on drilling through 2022 on tracts in the Eastern Gulf of Mexico that are within 125 miles of Florida, east of a dividing line known as the Military Mission Line, and in the Central Gulf of Mexico within 100 miles of Florida.

2009-01-01T23:59:59.000Z

442

Fate of nutrient enrichment on continental shelves as indicated by the C/N content of bottom sediments  

SciTech Connect (OSTI)

The trajectory and fate of particulate matter are poorly understood processes in a spatially heterogeneous coastal ocean. Parameterization of appropriate hydrodynamics for a quantitative description of these loss processes must thus await definition of the important biological time and space scales. Since the bottom sands tend to record the history of the water column, we have selected the C/N content of shelf sediments as a possible tracer of (1) sites of nutrient introduction to the shelf by various physical mechanisms, of (2) areas of subsequent downstream utilization by the phytoplankton, and of (3) where loss of particulate matter might occur from the water column. An analysis is made of the C/N patterns of bottom surface sediments in relation to the nitrogen sources from upwelling, river runoff, and tidal mixing on the Peruvian, west African, Amazonian, Gulf of Mexico, eastern US, Bering, and North Sea shelves in an initial attempt to proscribe the particle trajectories of organic matter on the continental shelf.

Walsh, J.J.; Premuzic, E.T.; Whitledge, T.E.

1980-01-01T23:59:59.000Z

443

Application of a Rule-Based Model to Estimate Mercury Exchange for Three Background Biomes in the Continental United States  

SciTech Connect (OSTI)

Ecosystems that have low mercury (Hg) concentrations (i.e., not enriched or impacted by geologic or anthropogenic processes) cover most of the terrestrial surface area of the earth yet their role as a net source or sink for atmospheric Hg is uncertain. Here we use empirical data to develop a rule-based model implemented within a geographic information system framework to estimate the spatial and temporal patterns of Hg flux for semiarid deserts, grasslands, and deciduous forests representing 45% of the continental United States. This exercise provides an indication of whether these ecosystems are a net source or sink for atmospheric Hg as well as a basis for recommendation of data to collect in future field sampling campaigns. Results indicated that soil alone was a small net source of atmospheric Hg and that emitted Hg could be accounted for based on Hg input by wet deposition. When foliar assimilation and wet deposition are added to the area estimate of soil Hg flux these biomes are a sink for atmospheric Hg.

Hartman, Jelena S. [University of Nevada, Reno; Weisberg, Peter J [University of Nevada, Reno; Pillai, Rekha [University of Nevada, Reno; Ericksen, Joey A. [University of Nevada, Reno; Gustin, Mae S. [University of Nevada, Reno; Kuiken, Todd [Tennessee Technological University; Zhang, Hong [Tennessee Technological University; Lindberg, Steven Eric [ORNL; Rytuba, J. J. [U.S. Geological Survey, Menlo Park, CA

2009-07-01T23:59:59.000Z

444

The Cascade of Tidal Energy from Low to High Modes on a Continental Slope SAMUEL M. KELLY* AND JONATHAN D. NASH  

E-Print Network [OSTI]

The Cascade of Tidal Energy from Low to High Modes on a Continental Slope SAMUEL M. KELLY. Kelly, University of Western Australia, M015 SESE, 35 Stirling Hwy., Crawley, WA 6009, Australia. E-mail: samuel.kelly@uwa.edu.au JULY 2012 K E L L Y E T A L . 1217 DOI: 10.1175/JPO-D-11-0231.1 Ã? 2012 American

445

Impact of Limitations on Access to Oil and Natural Gas Resources in the Federal Outer Continental Shelf (released in AEO2009)  

Reports and Publications (EIA)

The U.S. offshore is estimated to contain substantial resources of both crude oil and natural gas, but until recently some of the areas of the lower 48 states Outer Continental Shelf (OCS) have been under leasing moratoria. The Presidential ban on offshore drilling in portions of the lower 48 OCS was lifted in July 2008, and the Congressional ban was allowed to expire in September 2008, removing regulatory obstacles to development of the Atlantic and Pacific OCS.

2009-01-01T23:59:59.000Z

446

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

447

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

448

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

449

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

450

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

451

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

452

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

453

Holocene stratigraphy of the Alabama inner continental shelf: Influence of shelf sand ridges on determining lithofacies architecture  

SciTech Connect (OSTI)

Surface and subsurface distribution of lithofacies from Holocene sediments of the AL inner continental shelf was determined from a series of 59 vibracores and associated surface sediment grab sediments. Five Holocene lithofacies composed of 12 discrete microfacies were delineated based on grain size, color, sedimentary structures, shell content, and fabric of samples. These lithofacies include: (1) Graded Shelly Sand Lithofacies; (2) Clean Sand Lithofacies; (3) Dirty Sand Lithofacies; (4) Biogenic Sediment Lithofacies; and (5) Muddy Sediment Lithofacies. These represent four major depositional environments: The Shelf Sand Sheet Environment (lithofacies 1 and 2); the Sand Ridge Environment (lithofacies 1, 2, and 3); the Bay/Lagoon Environment (lithofacies 3, 4 and 5); and the Muddy Shelf Environment (lithofacies 5). East of the Main Pass of Mobile Bay, the seafloor is composed of a clean Shelf Sand Sheet with oblique shelf sand ridges; Clean Sand and Graded Shelly Sand are the dominant surface sediment types. Coarse shell beds that grade up to quartz sand units (total thickness 0.1 to 3+m) interpreted as tempestites comprise most of the upper portion of the ridges. West of the Pass, the muddier lithofacies (3 and 5) dominate surface samples. Microfacies at depth represent the early Holocene transgressive systems tract; these include the Muddy Shelf Depositional Environment and the filled estuaries and bays of the flooded Pleistocene fluvial valleys represented by the Bay/Lagoon Depositional Environment. The AL inner shelf provides an excellent model of the variability of sedimentation mode in time and space during deposition of a transgressive systems tract. Development of the palimpsest sand sheet/ridge complex progressed on the eastern shelf due to shut off of sediment influx, westward longshore currents, and episodic incidence of major hurricanes. On the western shelf a patchy distribution of muddier sediments developed from input of floodwaters from Mobile Bay.

Davies, D.J.; Parker, S.J. (Geological Survey of Alabama, Tuscaloosa, AL (United States). Energy and Coastal Geology Div.)

1993-03-01T23:59:59.000Z

454

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

455

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

456

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

457

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

458

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

459

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

460

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

Note: This page contains sample records for the topic "midlatitude continental convective" 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

CFD Calculation of Internal Natural Convection in the Annulus between Horizontal Concentric Cylinders  

SciTech Connect (OSTI)

The objective of this heat transfer and fluid flow study is to assess the ability of a computational fluid dynamics (CFD) code to reproduce the experimental results, numerical simulation results, and heat transfer correlation equations developed in the literature for natural convection heat transfer within the annulus of horizontal concentric cylinders. In the literature, a variety of heat transfer expressions have been developed to compute average equivalent thermal conductivities. However, the expressions have been primarily developed for very small inner and outer cylinder radii and gap-widths. In this comparative study, interest is primarily focused on large gap widths (on the order of half meter or greater) and large radius ratios. From the steady-state CFD analysis it is found that the concentric cylinder models for the larger geometries compare favorably to the results of the Kuehn and Goldstein correlations in the Rayleigh number range of about 10{sup 5} to 10{sup 8} (a range that encompasses the laminar to turbulent transition). For Rayleigh numbers greater than 10{sup 8}, both numerical simulations and experimental data (from the literature) are consistent and result in slightly lower equivalent thermal conductivities than those obtained from the Kuehn and Goldstein correlations.

N.D. Francis, Jr; M.T. Itamura; S.W. Webb; D.L. James

2002-10-01T23:59:59.000Z

462

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

463

Corrosion of type 316L stainless steel in a mercury thermal convection loop  

SciTech Connect (OSTI)

Two thermal convection loops fabricated from 316L stainless steel containing mercury (Hg) and Hg with 1000 wppm gallium (Ga), respectively, were operated continuously for about 5000 h. In each case, the maximum loop temperature was constant at about 305 degrees C and the minimum temperature was constant at about 242 degrees C. Coupons in the hot leg of the Hg-loop developed a posous surface layer substantially depleted of nickel and chromium, which resulted in a transformation to ferrite. The coupon exposed at the top of the hot leg in the Hg-loop experienced the maximum degradation, exhibiting a surface layer extending an average of 9-10 mu m after almost 5000 h. Analysis of the corrosion rate data as a function of temperature (position) in the Hg-loop suggests wetting by the mer cury occurred only above about 255 degrees C and that the rate limiting step in the corrosion process above 255 degrees C is solute diffusion through the saturated liquid boundary layer adjacent to the corroding surface. The latter factor suggests that the corrosion of 316L stainless steel in a mercury loop may be velocity dependent. No wetting and no corrosion were observed on the coupons and wall specimens removed from the Hg/Ga loop after 5000 h of operation.

DiStefano, J.R.; Manneschmidt, E.T.; Pawel, S.J.

1999-04-01T23:59:59.000Z

464

Impact of Resolution on Simulation of Closed Mesoscale Cellular Convection Identified by Dynamically Guided Watershed Segmentation  

SciTech Connect (OSTI)

Organized mesoscale cellular convection (MCC) is a common feature of marine stratocumulus that forms in response to a balance between mesoscale dynamics and smaller scale processes such as cloud radiative cooling and microphysics. We use the Weather Research and Forecasting model with chemistry (WRF-Chem) and fully coupled cloud-aerosol interactions to simulate marine low clouds during the VOCALS-REx campaign over the southeast Pacific. A suite of experiments with 3- and 9-km grid spacing indicates resolution-dependent behavior. The simulations with finer grid spacing have smaller liquid water paths and cloud fractions, while cloud tops are higher. The observed diurnal cycle is reasonably well simulated. To isolate organized MCC characteristics we develop a new automated method, which uses a variation of the watershed segmentation technique that combines the detection of cloud boundaries with a test for coincident vertical velocity characteristics. This ensures that the detected cloud fields are dynamically consistent for closed MCC, the most common MCC type over the VOCALS-REx region. We demonstrate that the 3-km simulation is able to reproduce the scaling between horizontal cell size and boundary layer height seen in satellite observations. However, the 9-km simulation is unable to resolve smaller circulations corresponding to shallower boundary layers, instead producing invariant MCC horizontal scale for all simulated boundary layers depths. The results imply that climate models with grid spacing of roughly 3 km or smaller may be needed to properly simulate the MCC structure in the marine stratocumulus regions.

Martini, Matus; Gustafson, William I.; Yang, Qing; Xiao, Heng

2014-11-27T23:59:59.000Z

465

Convective Instability Of The Solar Corona: Why The Solar Wind Blows  

E-Print Network [OSTI]

Chapman's (1957) conductive model of the solar corona is characterized by a temperature varying as r**(-2/7) with heliocentric distance r. The density distribution in this non-isothermal hydrostatic model has a minimum value at 123 RS, and increases with r above that altitude. It is shown that this hydrostatic model becomes convectively unstable above r = 35 RS, where the temperature lapse rate becomes superadiabatic. Beyond this radial distance heat conduction fails to be efficient enough to keep the temperature gradient smaller than the adiabatic lapse rate. We report the results obtained by Lemaire (1968) who showed that an additional mechanism is then required to transport the energy flux away from the Sun into interplanetary space. He pointed out that this additional mechanism is advection: i.e. the stationary hydrodynamic expansion of the corona. In other words the corona is unable to stay in hydrostatic equilibrium. The hydrodynamic solar wind expansion is thus a physical consequence of the too steep (...

Lemaire, Joseph

2012-01-01T23:59:59.000Z

466

Outer Continental Shelf Production  

U.S. Energy Information Administration (EIA) Indexed Site

Reference case projections. 3 The complete AEO2014, which was released in May, includes alternative assumptions regarding resources, technology advances, and world energy prices...

467

Impact of Aerosols on Tropical Cyclones: An Investigation Using Convection-permitting Model Simulation  

SciTech Connect (OSTI)

The role of aerosols effect on two tropical cyclones over Bay of Bengal are investigated using a convection permitting model with two-moment mixed-phase bulk cloud microphysics scheme. The simulation results show the role of aerosol on the microphysical and dynamical properties of cloud and bring out the change in efficiency of the clouds in producing precipitation. The tracks of the TCs are hardly affected by the changing aerosol types, but the intensity exhibits significant sensitivity due to the change in aerosol contribution. It is also clearly seen from the analyses that higher heating in the middle troposphere within the cyclone center is in response to latent heat release as a consequence of greater graupel formation. Greater heating in the middle level is particularly noticeable for the clean aerosol regime which causes enhanced divergence in the upper level which, in turn, forces the lower level convergence. As a result, the cleaner aerosol perturbation is more unstable within the cyclone core and produces a more intense cyclone as compared to other two perturbations of aerosol. All these studies show the robustness of the concept of TC weakening by storm ingestion of high concentrations of CCN. The consistency of these model results gives us confidence in stating there is a high probability that ingestion of high CCN concentrations in a TC will lead to weakening of the storm but has little impact on storm direction. Moreover, as pollution is increasing over the Indian sub-continent, this study suggests pollution may be weakening TCs over the Bay of Bengal.

Hazra, Anupam; Mukhopadhyay, P.; Taraphdar, Sourav; Chen, J. P.; Cotton, William R.

2013-07-16T23:59:59.000Z

468

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

469

Neutrino-driven supernova of a low-mass iron-core progenitor boosted by three-dimensional turbulent convection  

E-Print Network [OSTI]

We present the first successful simulation of a neutrino-driven supernova explosion in three dimensions (3D), using the Prometheus-Vertex code with an axis-free Yin-Yang grid and a sophisticated treatment of three-flavor, energy-dependent neutrino transport. The progenitor is a non-rotating, zero-metallicity 9.6 Msun star with an iron core. While in spherical symmetry outward shock acceleration sets in later than 300 ms after bounce, a successful explosion starts at ~130 ms post-bounce in two dimensions (2D). The 3D model explodes at about the same time but with faster shock expansion than in 2D and a more quickly increasing and roughly 10 percent higher explosion energy. The more favorable explosion conditions in 3D are explained by lower temperatures and thus reduced neutrino emission in the cooling layer below the gain radius. This moves the gain radius inward and leads to a bigger mass in the gain layer, whose larger recombination energy boosts the explosion energy in 3D. These differences are caused by less coherent, less massive, and less rapid convective downdrafts associated with post-shock convection in 3D. The less violent impact of these accretion downflows in the cooling layer produces less dissipative heating and therefore diminishes energy losses by neutrino emission. We thus have, for the first time, identified a reduced mass accretion rate, lower infall velocities, and a smaller surface filling factor of convective downdrafts as consequences of 3D postshock turbulence that facilitate neutrino-driven explosions and strengthen them compared to the 2D case.

Tobias Melson; Hans-Thomas Janka; Andreas Marek

2015-01-08T23:59:59.000Z

470

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

471

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

472

On the effect of the steady-state approximation in time-space composite studies of mesoscale convective systems  

E-Print Network [OSTI]

ON THE EFFECT OF THE STRA 'Y-STATE APPROXIMATION IN TIME-SPACE COMPOSITE STUDIES OF MESOSCALE CONVECTIVE SYSTEMS A Thesis KEVIN MORGAN MATTISON Subnitted to the Office of Graduate Studies of Texas A&M University in partial fulfillnent... of the requirements for the degree of MASTER OF SCIENCE Decenber 1992 Major Subject: Meteorology ON THE EFFECT OF THE STEADY-STATE APPROXINATIOH IN TIME-SPACE COMPOSITE STUDIES OF NESOSCALE COHVECTIVE SYSTENS A Thesis KEVIN MORGAN NATTISOH Approved as to style...

Mattison, Kevin Morgan

1992-01-01T23:59:59.000Z

473

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.

474

Comparison of entropy production rates in two different types of self-organized flows: Benard convection and zonal flow  

SciTech Connect (OSTI)

Two different types of self-organizing and sustaining ordered motion in fluids or plasmas--one is a Benard convection (or streamer) and the other is a zonal flow--have been compared by introducing a thermodynamic phenomenological model and evaluating the corresponding entropy production rates (EP). These two systems have different topologies in their equivalent circuits: the Benard convection is modeled by parallel connection of linear and nonlinear conductances, while the zonal flow is modeled by series connection. The ''power supply'' that drives the systems is also a determinant of operating modes. When the energy flux is a control parameter (as in usual plasma experiments), the driver is modeled by a constant-current power supply, and when the temperature difference between two separate boundaries is controlled (as in usual computational studies), the driver is modeled by a constant-voltage power supply. The parallel (series)-connection system tends to minimize (maximize) the total EP when a constant-current power supply drives the system. This minimum/maximum relation flips when a constant-voltage power supply is connected.

Kawazura, Y.; Yoshida, Z. [Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8561 (Japan)

2012-01-15T23:59:59.000Z

475

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

476

Studies of the General Circulation of the Atmosphere with a Simplified Moist  

E-Print Network [OSTI]

is whether these can build up and rapidly release convectively available potential energy. The formulation of moisture on midlatitude static stability, eddy scales, and energy transports (this section to be remarkably neutral with respect to moist convection. Despite the large changes in dry stability

Frierson, Dargan

477

Heat Flow and Gas Hydrates on the Continental Margin of India: Building on Results from NGHP Expedition 01  

SciTech Connect (OSTI)

The Indian National Gas Hydrate Program (NGHP) Expedition 01 presented the unique opportunity to constrain regional heat flow derived from seismic observations by using drilling data in three regions on the continental margin of India. The seismic bottom simulating reflection (BSR) is a well-documented feature in hydrate bearing sediments, and can serve as a proxy for apparent heat flow if data are available to estimate acoustic velocity and density in water and sediments, thermal conductivity, and seafloor temperature. Direct observations of temperature at depth and physical properties of the sediment obtained from drilling can be used to calibrate the seismic observations, decreasing the uncertainty of the seismically-derived estimates. Anomalies in apparent heat flow can result from a variety of sources, including sedimentation, erosion, topographic refraction and fluid flow. We constructed apparent heat flow maps for portions of the Krishna-Godavari (K-G) basin, the Mahanadi basin, and the Andaman basin and modeled anomalies using 1-D conductive thermal models. Apparent heat flow values in the Krishna-Godavari (K-G) basin and Mahanadi basin are generally 0.035 to 0.055 watts per square meter (W/m{sup 2}). The borehole data show an increase in apparent heat flow as water depth increases from 900 to 1500 m. In the SW part of the seismic grid, 1D modeling of the effect of sedimentation on heat flow shows that {approx}50% of the observed increase in apparent heat flow with increasing water depth can be attributed to trapping of sediments behind a 'toe-thrust' ridge that is forming along the seaward edge of a thick, rapidly accumulating deltaic sediment pile. The remainder of the anomaly can be explained either by a decrease in thermal conductivity of the sediments filling the slope basin or by lateral advection of heat through fluid flow along stratigraphic horizons within the basin and through flexural faults in the crest of the anticline. Such flow probably plays a role in bringing methane into the ridge formed by the toe-thrust. Because of the small anomaly due to this process and the uncertainty in thermal conductivity, we did not model this process explicitly. In the NE part of the K-G basin seismic grid, a number of local heat flow lows and highs are observed, which can be attributed to topographic refraction and to local fluid flow along faults, respectively. No regional anomaly can be resolved. Because of lack of continuity between the K-G basin sites within the seismic grid and those {approx}70 km to the NE in water depths of 1200 to 1500 m, we do not speculate on the reason for higher heat flow at these depths. The Mahanadi basin results, while limited in geographic extent, are similar to those for the K-G basin. The Andaman basin exhibits much lower apparent heat flow values, ranging from 0.015 to 0.025 W/m{sup 2}. Heat flow here also appears to increase with increasing water depth. The very low heat flow here is among the lowest heat flow observed anywhere and gives rise to a very thick hydrate stability zone in the sediments. Through 1D models of sedimentation (with extremely high sedimentation rates as a proxy for tectonic thickening), we concluded that the very low heat flow can probably be attributed to the combined effects of high sedimentation rate, low thermal conductivity, tectonic thickening of sediments and the cooling effect of a subducting plate in a subduction zone forearc. Like for the K-G basin, much of the local variability can be attributed to topography. The regional increase in heat flow with water depth remains unexplained because the seismic grid available to us did not extend far enough to define the local tectonic setting of the slope basin controlling this observational pattern. The results are compared to results from other margins, both active and passive. While an increase in apparent heat flow with increasing water depth is widely observed, it is likely a result of different processes in different places. The very low heat flow due to sedimentation and tectonics in the Andaman basi

Anne Trehu; Peter Kannberg

2011-06-30T23:59:59.000Z

478

Heat Flow and Gas Hydrates on the Continental Margin of India: Building on Results from NGHP Expedition 01  

SciTech Connect (OSTI)

The Indian National Gas Hydrate Program (NGHP) Expedition 01 presented the unique opportunity to constrain regional heat flow derived from seismic observations by using drilling data in three regions on the continental margin of India. The seismic bottom simulating reflection (BSR) is a well-documented feature in hydrate bearing sediments, and can serve as a proxy for apparent heat flow if data are available to estimate acoustic velocity and density in water and sediments, thermal conductivity, and seafloor temperature. Direct observations of temperature at depth and physical properties of the sediment obtained from drilling can be used to calibrate the seismic observations, decreasing the uncertainty of the seismically-derived estimates. Anomalies in apparent heat flow can result from a variety of sources, including sedimentation, erosion, topographic refraction and fluid flow. We constructed apparent heat flow maps for portions of the Krishna-Godavari (K-G) basin, the Mahanadi basin, and the Andaman basin and modeled anomalies using 1-D conductive thermal models. Apparent heat flow values in the Krishna-Godavari (K-G) basin and Mahanadi basin are generally 0.035 to 0.055 watts per square meter (W/m2). The borehole data show an increase in apparent heat flow as water depth increases from 900 to 1500 m. In the SW part of the seismic grid, 1D modeling of the effect of sedimentation on heat flow shows that ~50% of the observed increase in apparent heat flow with increasing water depth can be attributed to trapping of sediments behind a "toe-thrust" ridge that is forming along the seaward edge of a thick, rapidly accumulating deltaic sediment pile. The remainder of the anomaly can be explained either by a decrease in thermal conductivity of the sediments filling the slope basin or by lateral advection of heat through fluid flow along stratigraphic horizons within the basin and through flexural faults in the crest of the anticline. Such flow probably plays a role in bringing methane into the ridge formed by the toe-thrust. Because of the small anomaly due to this process and the uncertainty in thermal conductivity, we did not model this process explicitly. In the NE part of the K-G basin seismic grid, a number of local heat flow lows and highs are observed, which can be attributed to topographic refraction and to local fluid flow along faults, respectively. No regional anomaly can be resolved. Because of lack of continuity between the K-G basin sites within the seismic grid and those ~70 km to the NE in water depths of 1200 to 1500 m, we do not speculate on the reason for higher heat flow at these depths. The Mahanadi basin results, while limited in geographic extent, are similar to those for the KG basin. The Andaman basin exhibits much lower apparent heat flow values, ranging from 0.015 to 0.025 W/m2. Heat flow here also appears to increase with increasing water depth. The very low heat flow here is among the lowest heat flow observed anywhere and gives rise to a very thick hydrate stability zone in the sediments. Through 1D models of sedimentation (with extremely high sedimentation rates as a proxy for tectonic thickening), we concluded that the very low heat flow can probably be attributed to the combined effects of high sedimentation rate, low thermal conductivity, tectonic thickening of sediments and the cooling effect of a subducting plate in a subduction zone forearc. Like for the K-G basin, much of the local variability can be attributed to topography. The regional increase in heat flow with water depth remains unexplained because the seismic grid available to us did not extend far enough to define the local tectonic setting of the slope basin controlling this observational pattern. The results are compared to results from other margins, both active and passive. While an increase in apparent heat flow with increasing water depth is widely observed, it is likely a result of different processes in different places. The very low heat flow due to sedimentation and tectonics in the Andaman basin is at the low end of glob

Trehu, Anne; Kannberg, Peter

2011-06-30T23:59:59.000Z

479

Mathis, J. T. et al., (2012). Storm-induced upwelling of high pCO2 waters onto the continental shelf of the western Arctic Ocean and implications for carbonate mineral saturation states. Geophysical  

E-Print Network [OSTI]

Mathis, J. T. et al., (2012). Storm-induced upwelling of high pCO2 waters onto the continental. Zhao, and G. Vargo (2011). Did the northeastern Gulf of Mexico become greener after the Deepwater-driven sediment transport on sediment accumulation in the Cariaco Basin, Venezuela. Marine Geology. Muhling, B

Meyers, Steven D.

480

Numerical Modeling Studies of The Dissolution-Diffusion-Convection ProcessDuring CO2 Storage in Saline Aquifers  

SciTech Connect (OSTI)

For purposes of geologic storage, CO2 would be injected into saline formations at supercritical temperature and pressure conditions, and would form a separate phase that is immiscible with the aqueous phase (brine). At typical subsurface temperature and pressure conditions, supercritical CO2 (scCO2) has lower density than the aqueous phase and would experience an upward buoyancy force. Accordingly, the CO2 is expected to accumulate beneath the caprock at the top of the permeable interval, and could escape from the storage formation wherever (sub-)vertical pathways are available, such as fractures or faults through the caprock, or improperly abandoned wells. Over time, an increasing fraction of CO2 may dissolve in the aqueous phase, and eventually some of the aqueous CO2 may react with rock minerals to form poorly soluble carbonates. Dissolution into the aqueous phase and eventual sequestration as carbonates are highly desirable processes as they would increase permanence and security of storage. Dissolution of CO2 will establish phase equilibrium locally between the overlying CO2 plume and the aqueous phase beneath. If the aqueous phase were immobile, CO2 dissolution would be limited by the rate at which molecular diffusion can remove dissolved CO2 from the interface between CO2-rich and aqueous phases. This is a slow process. However, dissolution of CO2 is accompanied by a small increase in the density of the aqueous phase, creating a negative buoyancy force that can give rise to downward convection of CO2-rich brine, which in turn can greatly accelerate CO2 dissolution. This study explores the process of dissolution-diffusion-convection (DDC), using high-resolution numerical simulation. We find that geometric features of convection patterns are very sensitive to small changes in problem specifications, reflecting self-enhancing feedbacks and the chaotic nature of the process. Total CO2 dissolution rates on the other hand are found to be quite robust against modest changes in problem parameters, and are essentially constant as long as no dissolved CO2 reaches the lower boundary of the system.

Pruess, Karsten; Zhang, Keni

2008-11-17T23:59:59.000Z

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481

Q.J. R. Meteorol. SOC.(1997),123, pp. 1771-1778 Comments on `On large-scale circulations in convecting atmospheres' by  

E-Print Network [OSTI]

overview of the dynamics of convecting systems and their interaction with larger-scale cir- culations. As such it prompted us to organize a semester-long seminar devoted to the study of these interactions, and to ENB fluxes in generating instability, and go so far as to call it `an influential and lengthy dead-end road

Randall, David A.

482

Transport in a slowly perturbed convective cell flow. A. P. Itin 1 , R. de la Llave 2 , A. I. Neishtadt 1 , and A. A. Vasiliev 1  

E-Print Network [OSTI]

Transport in a slowly perturbed convective cell flow. A. P. Itin 1 , R. de la Llave 2 , A. I in such flows may be very sensitive to initial conditions, making possible chaotic advection [6] of passive­scales (of order # # -3 ln#). In case of a generic perturbation, a drop of passive impurity (e.g. dye) put

483

Constructal multi-scale package of vertical channels with natural convection and maximal heat transfer density. CONSTRUCTAL DESIGN: THE GENERATION OF MULTI-SCALE HEAT  

E-Print Network [OSTI]

transfer density. CONSTRUCTAL DESIGN: THE GENERATION OF MULTI-SCALE HEAT AND FLUID FLOW STRUCTURES-scale structures in natural convection with the objective of maximizing the heat transfer density, or the heat transfer rate per unit of volume§ . The flow volume is filled with vertical equidistant heated blades

Kihm, IconKenneth David

484

A Test of the Simulation of Tropical Convective Cloudiness by a Cloud-Resolving Model MARIO A. LOPEZ, DENNIS L. HARTMANN, PETER N. BLOSSEY, ROBERT WOOD,  

E-Print Network [OSTI]

un- certainties in projections of future climates (Bony et al. 2006; Solomon et al. 2007). Clouds solar radiation, although their effect on the net energy balance is often much less than with intense tropical convective systems are known to have long lifetimes and to cover large areas, accounting

Hartmann, Dennis

485

The Role of Convective Outflow in the Waldo Canyon Fire* RICHARD H. JOHNSON, RUSS S. SCHUMACHER, AND JAMES H. RUPPERT JR.  

E-Print Network [OSTI]

The Role of Convective Outflow in the Waldo Canyon Fire* RICHARD H. JOHNSON, RUSS S. SCHUMACHER-00361.s1. Corresponding author address: Richard H. Johnson, Dept. of Atmospheric Science, Colorado State University, 200 West Lake Street, 1371 Campus Delivery, Fort Collins, CO 80523-1371. E-mail: johnson

Johnson, Richard H.

486

Convective-Scale Variations in the Inner-Core Rainbands of a Tropical Cyclone ANTHONY C. DIDLAKE JR. AND ROBERT A. HOUZE JR.  

E-Print Network [OSTI]

Convective-Scale Variations in the Inner-Core Rainbands of a Tropical Cyclone ANTHONY C. DIDLAKE JR secondary eyewall forms at a certain radius, subsidence occurring along its inner edge separates it from the primary eyewall. 1. Introduction Improving intensity forecasts of tropical cyclones al- most certainly

Houze Jr., Robert A.

487

Convective-scale variations in the inner-core rainbands of a tropical cyclone Submitted for publication in Journal of the Atmospheric Sciences  

E-Print Network [OSTI]

Convective-scale variations in the inner-core rainbands of a tropical cyclone Submitted inner edge separates it from the primary eyewall. #12;3 1. Introduction Improving intensity forecasts of tropical cyclones almost certainly requires a better understanding of the structure and dynamics

Houze Jr., Robert A.

488

Solar cycle properties described by simple convection-driven dynamos This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-Print Network [OSTI]

Solar cycle properties described by simple convection-driven dynamos This article has been PUBLISHING PHYSICA SCRIPTA Phys. Scr. 86 (2012) 018407 (6pp) doi:10.1088/0031-8949/86/01/018407 Solar cycle. The assumption of the Boussinesq approximation made in these models prevents a realistic description of the solar

Simitev, Radostin D

489

Fabrication of FCC-SiO{sub 2} colloidal crystals using the vertical convective self-assemble method  

SciTech Connect (OSTI)

In order to determine the optimal conditions for the growth of high-quality 250 nm-SiO{sub 2} colloidal crystals by the vertical convective self-assemble method, the Design of Experiments (DoE) methodology is applied. The influence of the evaporation temperature, the volume fraction, and the pH of the colloidal suspension is studied by means of an analysis of variance (ANOVA) in a 3{sup 3} factorial design. Characteristics of the stacking lattice of the resulting colloidal crystals are determined by scanning electron microscopy and angle-resolved transmittance spectroscopy. Quantitative results from the statistical test show that the temperature is the most critical factor influencing the quality of the colloidal crystal, obtaining highly ordered structures with FCC stacking lattice at a growth temperature of 40°C.

Castañeda-Uribe, O. A.; Salcedo-Reyes, J. C.; Méndez-Pinzón, H. A. [Thin Films Group, Physics Department, Pontificia Universidad Javeriana, Cr. 7 No. 43-82, Ed. 53, Lab. 414, Bogotá, D.C. (Colombia); Pedroza-Rodríguez, A. M. [Microbiology Department, Pontificia Universidad Javeriana, Cr. 7 No. 43-82, Ed. 51, Lab. 101, Bogotá, D.C. (Colombia)

2014-05-15T23:59:59.000Z

490

Transport and deposition of particles in gas turbines: Effects of convection, diffusion, thermophoresis, inertial impaction and coagulation  

SciTech Connect (OSTI)

Aerosols are produced in a large number of industrial processes over a wide range of sizes. Of particular importance is deposition of coal and oil combustion aerosols in turbines. A model coupling the transport and the dynamics of aerosols to flow characteristics in gas turbines is presented. An order of magnitude analysis is carried out based on typical operational conditions for coal and oil combustion (neglecting coagulation) to determine the relative importance of various mechanisms on particle behavior. A scheme is then developed to incorporate a moment model of a log normally distributed aerosol to predict aerosol transport and dynamics in turbine flows. The proposed moment model reflects the contributions from convection, inertia, diffusion and thermophoresis. Aerosol behavior in various laminar 2-D and axisymmetric flows is considered in this study. Results are compared to published work in 1-D and 2-D planar and axisymmetric.

Brown, D.P.; Biswas, P.; Rubin, S.G. [Univ. of Cincinnati, OH (United States)

1994-12-31T23:59:59.000Z

491

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

SciTech Connect (OSTI)

In this paper, a phenomenological model of the thermal hydraulics of convective boiling in the post-critical-heat-flux (post-CHF) regime is developed and discussed. The model was implemented in the TRAC-PF1/MOD2 computer code (an advanced best-estimate computer program written for the analysis of pressurized water reactor systems). The model was built around the determination of flow regimes downstream of the quench front. The regimes were determined from the flow-regime map suggested by Ishii and his coworkers. Heat transfer in the transition boiling region was formulated as a position-dependent model. The propagation of the CHF point was strongly dependent on the length of the transition boiling region. Wall-to-fluid film boiling heat transfer was considered to consist of two components: first, a wall-to-vapor convective heat-transfer portion and, second, a wall-to-liquid heat transfer representing near-wall effects. Each contribution was considered separately in each of the inverted annular flow (IAF) regimes. The interfacial heat transfer was also formulated as flow-regime dependent. The interfacial drag coefficient model upstream of the CHF point was considered to be similar to flow through a roughened pipe. A free-stream contribution was calculated using Ishii's bubbly flow model for either fully developed subcooled or saturated nucleate boiling. For the drag in the smooth IAF region, a simple smooth-tube correlation for the interfacial friction factor was used. The drag coefficient for the rough-wavy IAF was formulated in the same way as for the smooth IAF model except that the roughness parameter was assumed to be proportional to liquid droplet diameter entrained from the wavy interface. The drag coefficient in the highly dispersed flow regime considered the combined effects of the liquid droplets within the channel and a liquid film on wet unheated walls. 431 refs., 6 figs., 4 tabs.

Nelson, R.A.; Unal, C.

1991-01-01T23:59:59.000Z

492

A study of mid-latitude tropopause characteristics during winter  

E-Print Network [OSTI]

meridian. The lati- tudes selected include the regions where the transition from polar to tropical air mass regimes takes place. The atmosphere in this area is thus in- fluenced by boththe polarfront and subtropical jet streams. The 90-day period chosen... investigator preferring the idea of multiple tropopauses, with each tropopause associated with a particular type of tropospheric air mass Sawyer (14) studied the day-to-day variations of the tropopause over Europe by analyzing tropopause contour charts...

Clark, Norman Johnson

1960-01-01T23:59:59.000Z

493

New nonlinear mechanisms of midlatitude atmospheric low-frequency variability  

E-Print Network [OSTI]

and Atmospheric Research Utrecht, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands Abstract

494

Results concerning the use of seismic and well log data for defining the geological model of the productive structures on the Romanian Continental Shelf of the Black Sea  

SciTech Connect (OSTI)

The contribution of the 3D seismics on the East-Lebada Structure of the Romanian Continental Shelf of the Black Sea, together with the complex well logging have led to the improvement of the reservoir geological model. The interpretation has been performed on 3d seismic profiles. Time migrated profiles were interpreted, by means of the program system OASIIS. The acoustic logging data were used for calibration, in order to identify the reflections corresponding to the geological boundary. By means of these reflections on the seismic profiles, the adequate geological model has been defined. A system of tectonic accidents which were not known till now were rendered evident. The interpretation of the complex well loggings, through the Well Log Analysis Program System - Express - allowed to determine the petrophysical-petrographical parameters necessary for reservoir evaluation, in correlation with core analysis. Thus, four horizons corresponding to the Albian age with favorable collector properties were rendered evident, in alternance with unfavorable collector properties zones. The well logs, performed at different time periods and with different tools were corrected and standardized for the well environment conditions and, depending on the logging program, different program modules were used to obtain the most adequate results. The parameter averaging performed by zones, for each well, together with the image furnished by the seismic data, allowed us to build the final geometrical and isoparametric model of the reservoir, used for further reservoir simulation. Based on the results obtained, the analysis was extended to West-Lebada Structure.

Babskow, A.; Baleanu, I.; Popa, D. [Institute for Research and Technology, Prahova (Romania)] [and others

1995-08-01T23:59:59.000Z

495

Impacts of Increased Access to Oil & Natural Gas Resources in the Lower 48 Federal Outer Continental Shelf (released in AEO2007)  

Reports and Publications (EIA)

This analysis was updated for Annual Energy Outlook 2009 (AEO): Impact of Limitations on Access to Oil and Natural Gas Resources in the Federal Outer Continental Shelf (OCS). The OCS is estimated to contain substantial resources of crude oil and natural gas; however, some areas of the OCS are subject to drilling restrictions. With energy prices rising over the past several years, there has been increased interest in the development of more domestic oil and natural gas supply, including OCS resources. In the past, federal efforts to encourage exploration and development activities in the deep waters of the OCS have been limited primarily to regulations that would reduce royalty payments by lease holders. More recently, the states of Alaska and Virginia have asked the federal government to consider leasing in areas off their coastlines that are off limits as a result of actions by the President or Congress. In response, the Minerals Management Service (MMS) of the U.S. Department of the Interior has included in its proposed 5-year leasing plan for 2007-2012 sales of one lease in the Mid-Atlantic area off the coastline of Virginia and two leases in the North Aleutian Basin area of Alaska. Development in both areas still would require lifting of the current ban on drilling.

2007-01-01T23:59:59.000Z

496

Development and testing of parameterizations for continental and tropical ice cloud microphysical and radiative properties in GCM and mesoscale models. Final report  

SciTech Connect (OSTI)

The overall purpose of this research was to exploit measurements in clouds sampled during several field programs, especially from experiments in tropical regions, in a four-component study to develop and validate cloud parameterizations for general circulation models, emphasizing ice clouds. The components were: (1) parameterization of basic properties of mid- and upper-tropospheric clouds, such as condensed water content, primarily with respect to cirrus from tropical areas; (2) the second component was to develop parameterizations which express cloud radiative properties in terms of basic cloud microphysical properties, dealing primarily with tropical oceanic cirrus clouds and continental thunderstorm anvils, but also including altocumulus clouds; (3) the third component was to validate the parameterizations through use of ground-based measurements calibrated using existing and planned in-situ measurements of cloud microphysical properties and bulk radiative properties, as well as time-resolved data collected over extended periods of time; (4) the fourth component was to implement the parameterizations in the National Center for Atmospheric Research (NCAR) community climate model (CCM) II or in the NOAA-GFDL model (by L. Donner GFDL) and to perform sensitivity studies.

Heymsfield, A.

1997-09-01T23:59:59.000Z

497

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

498

The design, construction, and instrumentation of a chamber to study heat, mass, and momentum transfer from humid air to metal under conditions of frosting and free convection  

E-Print Network [OSTI]

THE DESIGN? CONSTRUCTION? AND INSTRUMENTATION OF A CEAMSER TO STUDY HEAT, MASS? AND MOSNTUM TRANSFER FROM HUMID AIR TO METAL UNDER CONDITIONS OF FROSTING AND FREE CONVECTION A Thesis By James P. Hutchison Submitted to the Graduate School... temperatures a cryogenic pump wss necessary. The sire of the pump was computed on the basis of maintaining a one degree Fahrenheit drop of the coolant temperature through the supply systms. The greatest heat load on the supply system being 3718 BTU per hour...

Hutchison, James P

1961-01-01T23:59:59.000Z

499

The effects of convection criteria on the evolution of population III stars and the detectability of their supernovae  

E-Print Network [OSTI]

The first stars continue to elude modern telescopes, but much has been accomplished in observing the glow of the first galaxies. As detection capabilities improve we will eventually resolve these galaxies, but hopes of observing an individual star remains dim for the foreseeable future. However, our first view of an individual first star may be possible due to its explosion. In this work, we present evolution calculations for Population III (Pop III) stars and their subsequent supernovae explosions. Our evolution models include a mass range of 15 - 100 M$_\\odot$, each with initial heavy element abundance Z = 10-14. Our models are evolved from pre-main sequence through formation of an iron core, and thus near to core collapse. We find that modelling the evolution of these stars is very sensitive to the choice of convection criterion; here we provide evolution results using both the Schwarzschild and Ledoux criteria. We also use the final structure from our models for numerical simulation of their supernovae li...

Lawlor, T M; Teffs, J; MacDonald, J

2015-01-01T23:59:59.000Z

500

Role of stochasticity in turbulence and convective intermittent transport at the scrape off layer of Ohmic plasma in QUEST  

SciTech Connect (OSTI)

Statistical features of fluctuations are investigated using the fast camera imaging technique in the scrape of layer (SOL) of electron cyclotron resonance heated Ohmic plasma. Fluctuations in the SOL towards low field side are dominated by coherent convective structures (blobs). Two dimensional structures of the higher order moments (skewness s and kurtosis k) representing the shape of probability density function (PDF) are studied. s and k are seen to be functions of the magnetic field lines. s and k are consistently higher towards the bottom half of the vessel in the SOL showing the blob trajectory along the field lines from the top towards bottom of the vessel. Parabolic relation (k=As{sup 2}+C) is observed between s and k near the plasma boundary, featuring steep density gradient region and at the far SOL. The coefficient A, obtained experimentally, indicates a shift of prominence from pure drift-wave instabilities towards fully developed turbulence. Numerical coefficients characterizing the Pearson system are derived which demonstrates the progressive deviation of the PDF from Gaussian towards gamma from the density gradient region, towards the far SOL. Based on a simple stochastic differential equation, a direct correspondence between the multiplicative noise amplitude, increased intermittency, and hence change in PDF is discussed.

Banerjee, Santanu, E-mail: sbanerje@ipr.res.in; Ishiguro, M.; Tashima, S.; Mishra, K. [IGSES, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Zushi, H.; Hanada, K.; Nakamura, K.; Idei, H.; Hasegawa, M.; Fujisawa, A.; Nagashima, Y.; Matsuoka, K. [RIAM, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Nishino, N. [Mechanical System Engineering, Hiroshima University, Hiroshima 739-8527 (Japan); Liu, H. Q. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

2014-07-15T23:59:59.000Z