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Note: This page contains sample records for the topic "droplet size distribution" 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.


1

Evolution of droplet size distribution and autoconversion parameteriza...  

NLE Websites -- All DOE Office Websites (Extended Search)

Evolution of droplet size distribution and autoconversion parameterization in turbulent clouds McGraw, Robert Brookhaven National Laboratory Liu, Yangang Brookhaven National...

2

Cloud Droplet Size Distributions in Low-Level Stratiform Clouds  

Science Conference Proceedings (OSTI)

A database of stratus cloud droplet (diameter <50 ?m) size distribution parameters, derived from in situ data reported in the existing literature, was created, facilitating intercomparison among datasets and quantifying typical values and their ...

Natasha L. Miles; Johannes Verlinde; Eugene E. Clothiaux

2000-01-01T23:59:59.000Z

3

A New Mechanism of Droplet Size Distribution Broadening during Diffusional Growth  

Science Conference Proceedings (OSTI)

A new mechanism has been developed for size distribution broadening toward large droplet sizes. This mechanism may explain the rapid formation of large cloud droplets, which may subsequently trigger precipitation formation through the collision–...

Alexei Korolev; Mark Pinsky; Alex Khain

2013-07-01T23:59:59.000Z

4

Progress on Predicting the Breadth of Droplet Size Distributions Observed in Small Cumuli  

Science Conference Proceedings (OSTI)

A modeling framework representing variations in droplet growth by condensation, resulting from different saturation histories experienced as a result of entrainment and mixing, is used to predict the breadth of droplet size distributions observed ...

Jennifer L. Bewley; Sonia Lasher-Trapp

2011-12-01T23:59:59.000Z

5

Effects of Variable Droplet Growth Histories on Droplet Size Distributions. Part I: Theory  

Science Conference Proceedings (OSTI)

A theoretical framework is developed that permits estimation of the effects of fluctuating supersaturation on the development of cloud droplet size spectra. The studies focus on the role of turbulent fluctuations in vertical wind and in the ...

William A. Cooper

1989-05-01T23:59:59.000Z

6

A Generalized Systems Theory for the Effect of Varying Fluctuations on Cloud Droplet Size Distributions  

Science Conference Proceedings (OSTI)

A systems theory has previously been developed by Liu and Hallett to interpret droplet size distributions in turbulent clouds by utilizing ideas from statistical physics and information theory. The present paper generalizes that systems theory to ...

Yangang Liu; Peter H. Daum; John Hallett

2002-07-01T23:59:59.000Z

7

Improvements of Droplet Size Distribution Measurements with the Fast-FSSP (Forward Scattering Spectrometer Probe)  

Science Conference Proceedings (OSTI)

The basics of single particle measurements are discussed and illustrated with measurements of the droplet size distribution with an optical spectrometer, the Forward Scattering Spectrometer Probe (FSSP), and its improved version, the Fast-FSSP. ...

Jean-Louis Brenguier; Thierry Bourrianne; Afraniode Araujo Coelho; Jacques Isbert; Robert Peytavi; Dominique Trevarin; Perry Weschler

1998-10-01T23:59:59.000Z

8

Dispersion of Cloud Droplet Size Distributions, Cloud Parameterization...  

NLE Websites -- All DOE Office Websites (Extended Search)

National Laboratory Upton, New York Introduction Most studies of the effect of aerosols on cloud radiative properties have considered only changes in the cloud droplet...

9

ARM - Measurement - Cloud droplet size  

NLE Websites -- All DOE Office Websites (Extended Search)

droplet size droplet size ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud droplet size Linear size (e.g. radius or diameter) of a cloud particle Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. Field Campaign Instruments CPI : Cloud Particle Imager CVI-AIR : Counterflow Virtual Impactor MIRAI : JAMSTEC Research Vessel Mirai PDI : Phase Doppler Interferometer UAV-PROTEUS-MICRO : Proteus Cloud Microphysics Instruments SPEC-CPI : Stratton Park Engineering Company - Cloud particle imager

10

Analytic Solutions for Evolving Size Distributions of Spherical Crystals or Droplets Undergoing Diffusional Growth in Different Regimes  

Science Conference Proceedings (OSTI)

Motivated by simulations of slow-growing contrail cirrus, the solution of the diffusional growth equations for a population of spherical ice crystals or water droplets is reexamined. For forcing specified by the evolution of the total water ...

D. C. Lewellen

2012-02-01T23:59:59.000Z

11

Effects of droplet size on intrusion of sub-surface oil spills  

E-Print Network (OSTI)

This thesis explores the effects of droplet size on droplet intrusion in sub-surface oil spills. Laboratory experiments were performed where glass beads of various sizes, which serve to simulate oil droplets in deepsea oil ...

Chan, Godine Kok Yan

2013-01-01T23:59:59.000Z

12

Effect of droplet size on the behavior and characteristics of emulsified acid  

E-Print Network (OSTI)

Emulsified acids have been extensively used in the oil industry since 1933. Most of the available research and publications discussed mainly the application of emulsified acid in the field. A fair number of the published work also discussed in depth some of the emulsified acid properties such viscosity, stability and reactivity. However, all of the available research discussed the emulsified acid without sufficient details of its preparation. Beside their chemical composition, the ways emulsified acids are prepared cause significant differences in their physical properties. The characterization of emulsified acid by its droplet size and size distribution complements its chemical composition and gives the emulsified acid a unique description and thus reproducible properties. No previous study considered the impact of the droplet size on the characteristics and properties of emulsified acid. Therefore, the main objective of this research is to study the effects of the droplet size on various properties of emulsified acid such as viscosity, stability and reactivity. Results showed that the droplet size and size distribution have a strong effect on the stability, viscosity and diffusion rate of the emulsified acid. The results of this work are important because knowledge of the effect of the droplet size on major design parameters will guide the way emulsified acid is prepared and applied in the field.

Almutairi, Saleh Haif

2008-05-01T23:59:59.000Z

13

Raindrop Size Distribution  

Science Conference Proceedings (OSTI)

This paper reviews some of the published results relating to raindrop-size distributions and couples this with some of the authors' results in order to show that the mathematical description of the distribution can be divided into three ...

M. C. Hodson

1986-07-01T23:59:59.000Z

14

Multimodal Raindrop Size Distributions  

Science Conference Proceedings (OSTI)

The raindrop size distributions (DSDs) observed over a short span usually have an erratic shape, with several relative maxima. This multimodal structure is studied from disdrometer data acquired in tropical and midlatitude areas. It is shown that ...

Henri Sauvageot; Manlandon Koffi

2000-08-01T23:59:59.000Z

15

Surface area generation and droplet size control in solvent extraction systems utilizing high intensity electric fields  

DOE Patents (OSTI)

A method and system for solvent extraction where droplets are shattered by a high intensity electric field. These shattered droplets form a plurality of smaller droplets which have a greater combined surface area than the original droplet. Dispersion, coalescence and phase separation are accomplished in one vessel through the use of the single pulsing high intensity electric field. Electric field conditions are chosen so that simultaneous dispersion and coalescence are taking place in the emulsion formed in the electric field. The electric field creates a large amount of interfacial surface area for solvent extraction when the droplet is disintegrated and is capable of controlling droplet size and thus droplet stability. These operations take place in the presence of a counter current flow of the continuous phase.

Scott, Timothy C. (Knoxville, TN); Wham, Robert M. (Oak Ridge, TN)

1988-01-01T23:59:59.000Z

16

Combustion characteristics of fuel droplets with addition of nano and micron-sized aluminum particles  

E-Print Network (OSTI)

Combustion characteristics of fuel droplets with addition of nano and micron-sized aluminum form 27 July 2010 Accepted 3 September 2010 Keywords: High-energy-density fuels Droplet combustion n-decane-based fuels. Five distinctive stages (preheating and ignition, classical combustion

Qiao, Li

17

An Optical Device for the Measurement of Droplet Size Spectra in Calm or Low Wind Conditions  

Science Conference Proceedings (OSTI)

An instrument for measuring the size and concentration of droplets is described. It has the ability to function in calm and low wind conditions. Droplets in the 5–50 ?m diameter range are detected optically. The data acquisition and real-time ...

T. Perrin; A. Rigaud; C. Pontikis; M. Cabane

1989-12-01T23:59:59.000Z

18

Chemical Heterogeneity across Cloud Droplet Size Spectra in Continental and Marine Air Masses  

Science Conference Proceedings (OSTI)

Variations in the chemical composition of cloud droplets of different sizes are predicted in models. Measurements made in natural clouds to verify this prediction are extremely limited, however. During the spring of 1995 and the summers of 1995 ...

Surabi Menon; V. K. Saxena; B. D. Logie

2000-06-01T23:59:59.000Z

19

The Modified Gamma Size Distribution Applied to Inhomogeneous and Nonspherical Particles: Key Relationships and Conversions  

Science Conference Proceedings (OSTI)

The four-parameter modified gamma distribution (MGD) is the most general mathematically convenient model for size distributions of particle types ranging from aerosols and cloud droplets or ice particles to liquid and frozen precipitation. The ...

Grant W. Petty; Wei Huang

2011-07-01T23:59:59.000Z

20

Intercomparison of Instruments used for Measurement of Cloud Drop Concentration and Size Distribution  

Science Conference Proceedings (OSTI)

Measurements of drop concentration and size distribution with the Clague droplet gun and the Forward Scattering Spectrometer Probe in 21 cumulus clouds on five days show no evidence of systematic differences between the two instruments. Though ...

S. C. Mossop

1983-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Flame inhibition/suppression by water mist: Droplet size ...  

Science Conference Proceedings (OSTI)

... 1. Analysis of the flame structure and critical flame ... In the present work, the inhibition of a one ... sizes, the underlying reason for the breakdown in the ...

2012-07-27T23:59:59.000Z

22

ARM - Measurement - Hydrometeor Size Distribution  

NLE Websites -- All DOE Office Websites (Extended Search)

Size Distribution Size Distribution ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Hydrometeor Size Distribution The number of hydrometeors observed in a given size range. Categories Cloud Properties, Atmospheric State Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments LDIS : Laser Disdrometer Datastreams LDIS : Laser Disdrometer Datastreams PARS2 : OTT Parsivel2 Laser Disdrometer VDIS : Video Disdrometer Datastreams VDIS : Video Disdrometer Drop Size Distribution

23

Crystal Size and Orientation in Ice Grown by Droplet Accretion in Wet and Spongy Regimes  

Science Conference Proceedings (OSTI)

The size and orientation of crystal grains in wet and spongy ice formed by accretion of supercooled droplets has been determined in a wide range of air temperatures (?8 to ?25°C). Particular care has been taken in reducing the spurious ice ...

F. Prodi; L. Levi; A. Franzini; C. Scarani

1982-10-01T23:59:59.000Z

24

Exponential Size Distributions for Snow  

Science Conference Proceedings (OSTI)

Using airborne data from several recent field projects, the authors have taken another look at the properties of exponential ice particle size distributions (PSDs) when the PSDs are broad. Two primary questions are addressed: for what ranges of ...

Andrew J. Heymsfield; Paul Field; Aaron Bansemer

2008-12-01T23:59:59.000Z

25

Parameterizing the Raindrop Size Distribution  

Science Conference Proceedings (OSTI)

This paper addresses the problem of finding a parametric form for the raindrop size distribution (DSD) that 1) is an appropriate model for tropical rainfall, and 2) involves statistically independent parameters. Such a parameterization is derived ...

Ziad S. Haddad; Stephen L. Durden; Eastwood Im

1996-01-01T23:59:59.000Z

26

Field Observations of In-Cloud Nucleation and the Modification of Atmospheric Aerosol Size Distributions after Cloud Evaporation  

Science Conference Proceedings (OSTI)

The authors measured aerosol and droplet size distributions in the range from 0.1 to 50 µm, concentrations and sizes of precipitation particles, concentrations of condensation nuclei, and state parameters in and in the vicinity of a towering ...

A. J. Alkezweeny

1995-12-01T23:59:59.000Z

27

ARM - Measurement - Particle size distribution  

NLE Websites -- All DOE Office Websites (Extended Search)

size distribution size distribution ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Particle size distribution The number of particles present in any given volume of air within a specified size range. Categories Aerosols Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments AOS : Aerosol Observing System CSPHOT : Cimel Sunphotometer TDMA : Tandem Differential Mobility Analyzer UHSAS : Ultra-High Sensitivity Aerosol Spectrometer Field Campaign Instruments

28

Generalisation of Levine's prediction for the distribution of freezing temperatures of droplets: A general singular model for ice nucleation  

E-Print Network (OSTI)

Models without an explicit time dependence, called singular models, are widely used for fitting the distribution of temperatures at which water droplets freeze. In 1950 Levine developed the original singular model. His key assumption was that each droplet contained many nucleation sites, and that freezing occurred due to the nucleation site with the highest freezing temperature. The fact that freezing occurs due to the maximum value out of large number of nucleation temperatures, means that we can apply the results of what is called extreme-value statistics. This is the statistics of the extreme, i.e., maximum or minimum, value of a large number of random variables. Here we use the results of extreme-value statistics to show that we can generalise Levine's model to produce the most general singular model possible. We show that when a singular model is a good approximation, the distribution of freezing temperatures should always be given by what is called the generalised extreme-value distribution. In addition, we also show that the distribution of freezing temperatures for droplets of onesize, can be used to make predictions for the scaling of the median nucleation temperature with droplet size, and vice versa.

Richard P. Sear

2013-07-29T23:59:59.000Z

29

Dryout droplet distribution and dispersed flow film boiling  

E-Print Network (OSTI)

Dispersed flow film boiling is characterized by liquid-phase droplets entrained in a continuous vapor-phase flow. In a previous work at MIT, a model of dispersed flow heat transfer was developed, called the Local Conditions ...

Hill, Wayne S.

1982-01-01T23:59:59.000Z

30

Peaks in Raindrop Size Distributions  

Science Conference Proceedings (OSTI)

The multipeak behavior of raindrop size distributions has been studied. Peaks have been found for distinct drop diameters: 0.7, 1.0, 1.9, and possibly 3.2 mm. The probability is about 65% that at least one of these peaks exists in an observed ...

M. Steiner; A. Waldvogel

1987-10-01T23:59:59.000Z

31

Production mechanisms, number concentration, size distribution...  

NLE Websites -- All DOE Office Websites (Extended Search)

Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002asl2.441 Meeting Report Production mechanisms, number concentration, size distribution, chemical composition, and...

32

Gamma Size Distribution and Stochastic Sampling Errors  

Science Conference Proceedings (OSTI)

A maximum likelihood approach to the application of the gamma size distribution is described and compared with the method of moments approach suggested by Ulbrich. Estimation of distribution parameters based on the maximum likelihood principle ...

Raymond K. W. Wong; Norman Chidambaram

1985-06-01T23:59:59.000Z

33

The Shape of Averaged Drop Size Distributions  

Science Conference Proceedings (OSTI)

The shape of averaged drop size distributions (DSD) is studied from a large sample of data (892 h) collected at several sites of various latitudes. The results show that neither the hypothesis of an exponential distribution to represent rainfall ...

Henri Sauvageot; Jean-Pierre Lacaux

1995-04-01T23:59:59.000Z

34

A New Parameterization of Cloud Droplet Activation Applicable to General Circulation Models  

Science Conference Proceedings (OSTI)

A new parameterization is proposed to link the droplet number concentration to the size distribution and chemical composition of aerosol and updraft velocity. Except for an empirical assumption of droplet growth, the parameterization is ...

Yi Ming; V. Ramaswamy; Leo J. Donner; Vaughan T. J. Phillips

2006-04-01T23:59:59.000Z

35

Droplet Growth in Warm Water Clouds Observed by the A-Train. Part I: Sensitivity Analysis of the MODIS-Derived Cloud Droplet Sizes  

Science Conference Proceedings (OSTI)

This study examines the sensitivity of the retrieved cloud droplet radii (CDR) to the vertical inhomogeneity of droplet radii, including the existence of a drizzle mode in clouds. The focus of this study is warm water-phase clouds. Radiative ...

Takashi Y. Nakajima; Kentaroh Suzuki; Graeme L. Stephens

2010-06-01T23:59:59.000Z

36

Mixing and the Evolution of Cloud Droplet Size Spectra in a Vigorous Continental Cumulus  

Science Conference Proceedings (OSTI)

Aircraft measurements in a vigorous, highly turbulent continental cumulus show predominantly bimodal and multiple peaked cloud droplet spectral shapes. The data are 100 m (1 s) averages. Three factors involved in the development of the cloud ...

Ilga R. Paluch; Charles A. Knight

1984-06-01T23:59:59.000Z

37

Analysis of Rotating Multicylinder Data in Measuring Cloud-Droplet Size and Liquid Water Content  

Science Conference Proceedings (OSTI)

An objective method is presented for the analysis of rotating multicylinder data in measuring the liquid water content and median volume droplet diameter of icing clouds. The method is based on time-dependent numerical modeling of cylinder icing ...

Lasse Makkonen

1992-06-01T23:59:59.000Z

38

Gradually Truncated Log-normal distribution- Size distribution of firms  

E-Print Network (OSTI)

Many natural and economical phenomena are described through power law or log-normal distributions. In these cases, probability decreases very slowly with step size compared to normal distribution. Thus it is essential to cut-off these distributions for larger step size. Recently we introduce the gradually truncated power law distribution to successfully describe variation of financial, educational, physical and citation index. In the present work, we introduce gradually truncated log-normal distribution in which we gradually cut-off larger steps due to physical limitation of the system. We applied this distribution successfully to size distribution of USA´s manufactoring firms which is measured through their annual sell. The physical limitation are due to limited market size or shortage of highly competent executives. I.

Hari M. Gupta; José R. Campanha

2008-01-01T23:59:59.000Z

39

Particle size distribution instrument. Topical report 13  

DOE Green Energy (OSTI)

The development of an instrument to measure the concentration of particles in gas is described in this report. An in situ instrument was designed and constructed which sizes individual particles and counts the number of occurrences for several size classes. Although this instrument was designed to detect the size distribution of slag and seed particles generated at an experimental coal-fired magnetohydrodynamic power facility, it can be used as a nonintrusive diagnostic tool for other hostile industrial processes involving the formation and growth of particulates. Two of the techniques developed are extensions of the widely used crossed beam velocimeter, providing simultaneous measurement of the size distribution and velocity of articles.

Okhuysen, W.; Gassaway, J.D.

1995-04-01T23:59:59.000Z

40

Raindrop Size Distribution Measurements in Tropical Cyclones  

Science Conference Proceedings (OSTI)

Characteristics of the raindrop size distribution in seven tropical cyclones have been studied through impact-type disdrometer measurements at three different sites during the 2004–06 Atlantic hurricane seasons. One of the cyclones has been ...

Ali Tokay; Paul G. Bashor; Emad Habib; Takis Kasparis

2008-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Acoustic Sounding of Raindrop Size Distribution  

Science Conference Proceedings (OSTI)

Radars have been successfully used for remote measurements of raindrop size distribution and rain intensity for many years. Over the last two decades, sodars have been increasingly applied to measure the parameters of precipitation. In the ...

Sergei V. Shamanaev

2003-01-01T23:59:59.000Z

42

A General Formulation for Raindrop Size Distribution  

Science Conference Proceedings (OSTI)

A general phenomenological formulation for drop size distribution (DSD), written down as a scaling law, is proposed. It accounts for all previous fitted DSDs. As a main implication of the expression proposed, the integral rainfall variables are ...

Daniel Sempere Torres; Josep M. Porrà; Jean-Dominique Creutin

1994-12-01T23:59:59.000Z

43

What is a Raindrop Size Distribution?  

Science Conference Proceedings (OSTI)

It is commonly understood that the number of drops that one happens to measure as a function of diameter in some sample represents the drop size distribution. However, recent observations show that rain is "patchy" suggesting that such a ...

A. R. Jameson; A. B. Kostinski

2001-06-01T23:59:59.000Z

44

Description of sprays using joint hyperbolic distribution in particle size and velocity  

SciTech Connect

The joint probability density functions of droplet size and velocity have been represented in sprays by the two-dimensional hyperbolic distribution. A distribution is provided, and a procedure to compute its eight parameters outlined. Analytical expressions for certain statistical quantities, such as mean diameters, momentum, kinetic energy etc., applicable under certain restrictions, are obtained. The computations for a water spray issuing from a Danfoss 60{degrees} solid cone oil-burner nozzle demonstrate not only that the hyperbolic distribution provides an excellent approximation for the joint size and velocity distributions for the measurements taken along the entire length of the spray axis, but also that such representation presents a clear insight into the physics of the motion and the related size formation. The computations reveal a developing region, with areas dominated by breakup or coalescence of droplets, followed by a developed state with little change in droplet size but continuously decreasing velocity. It is concluded that this novel approach is well suited to the description of sprays.

Bhatia, J.C.; Durst, F. (LSTM-Erlangen, Lehrstuhl fur Stromungsmechanik, Universitat Erlangen-Nurnberg, 8520 Erlangen (DE))

1990-09-01T23:59:59.000Z

45

Crushed Coal Particle Size Distribution Monitoring  

Science Conference Proceedings (OSTI)

This report summarizes an evaluation of different commercially available technologies for on-line monitoring of crushed coal size distribution with a subsequent laboratory test of the most promising system. The technology evaluation focused on image-based approaches for evaluating crushed coal size distribution that would address previous challenges encountered, including depth of field, image scale dependency upon the distance of the sample from the lens, image shadows caused by perimeter lighting, ...

2013-09-11T23:59:59.000Z

46

ARM - Measurement - Cloud particle size distribution  

NLE Websites -- All DOE Office Websites (Extended Search)

size distribution size distribution ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud particle size distribution The number of cloud particles present in any given volume of air within a specified size range, including liquid and ice. Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments WSACR : Scanning ARM Cloud Radar, tuned to W-Band (95GHz) Field Campaign Instruments CPI : Cloud Particle Imager CLDAEROSMICRO : Cloud and Aerosol Microphysical Properties

47

ARM - Measurement - Aerosol particle size distribution  

NLE Websites -- All DOE Office Websites (Extended Search)

particle size distribution particle size distribution ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Aerosol particle size distribution The number of aerosol particles present in any given volume of air within a specificied size range Categories Aerosols Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments SMPS : Scanning mobility particle sizer TDMA : Tandem Differential Mobility Analyzer UHSAS : Ultra-High Sensitivity Aerosol Spectrometer Field Campaign Instruments

48

Infrared measurements of soot formation and droplet sizes in diesel sprays. Final report, June 6, 1987--December 31, 1990  

DOE Green Energy (OSTI)

This report describes an investigation of diesel sprays using a combination of infrared wavelength optical diagnostics to probe the high droplet number density region surrounding the injector tip. Infrared wavelengths were shown to be more effective than visible or ultraviolet wavelength light at penetrating this region of the spray. This success is easily explained by the decrease in optical cross section of small diameter drops (less than 10 {mu}m) for a wavelength shift from the visible to wavelengths near 10 {mu}m. Two types of diagnostics were implemented. First, a custom manufactured, high speed infrared spectrometer was used to monitor the spectral region between 6 and 12 {mu}m in 0.5 {mu}m intervals. Spectra from this instrument, for specific locations in the combusting spray were used to monitor the development of soot in the spray. The second diagnostic technique used three collinear laser beams focussed into a 0.25 mm beam to monitor the droplet size in the spray. This measurement uses a ratio of signals to remove the droplet number density as a variable and the observed signal ratio is a direct indication of the average (using an approximate radius to the fourth power weighting function) droplet size. The experiments were performed using a shock tube to simulate the conditions typical of diesel combustion (700 to 900 K in temperature and approximately 3.0 MPa in pressure) and a custom manufactured single shot fuel injection system. Optical access in the shock tube included visible and infrared transmissive windows arranged to provide orthogonal access in two directions and perpendicular to the spray axis. The fuel injection system for this work was configured to produce approximately 20 MPa of injection pressure and produced a single injection approximately 2 ms after the injection trigger. This system could therefore be controlled to inject into the quiescent reflected region of the shock tube after the incident shock reflection from the end wall.

Parker, T.E.; Morency, J.R.; Foutter, R.R.; Rawlins, W.T.

1992-07-01T23:59:59.000Z

49

The Distribution of Cloud Horizontal Sizes  

Science Conference Proceedings (OSTI)

Cloud horizontal size distributions from near-global satellite data, from aircraft, and from a global high-resolution numerical weather prediction model, are presented for the scale range 0.1–8000 km and are shown to be well-represented using a ...

Robert Wood; Paul R. Field

2011-09-01T23:59:59.000Z

50

The Sampling Variations of Hailstone Size Distributions  

Science Conference Proceedings (OSTI)

The use of a shifted gamma size distribution for hailstone samples is proposed. This is shown to provide a better fit than the usual exponential form, using time-resolved Alberta data. It is also concluded that there is a dependence of the shape ...

Raymond K. W. Wong; Norman Chidambaram; Lawrence Cheng; Marianne English

1988-03-01T23:59:59.000Z

51

City Size Distributions For India and China  

E-Print Network (OSTI)

This paper studies the size distributions of urban agglomerations for India and China. We have estimated the scaling exponent for the Zipf's law with the Indian census data for the years of 1981-2001 and the Chinese census data for 1990 and 2000. Along with the biased linear fit estimate, the maximum likelihood estimate for the Pareto and Tsallis q-exponential distribution has been computed. For India, the scaling exponent is in the range of [1.88, 2.06] and for China, it is in the interval [1.82, 2.29]. The goodness-of-fit tests of the estimated distributions are performed using the Kolmogorov-Smirnov statistic.

Gangopadhyay, Kausik

2010-01-01T23:59:59.000Z

52

Droplet Spectra Broadening by Ripening Process. Part I: Roles of Curvature and Salinity of Cloud Droplets  

Science Conference Proceedings (OSTI)

The “ripening process” occurs due to thermodynamic instability of droplet size spectra in clouds. This instability results from the existence of droplets with different salinity and size in the droplet spectra. The ripening process is independent ...

Fikrettin Çelik; John D. Marwitz

1999-09-01T23:59:59.000Z

53

Increase of Cloud Droplet Size with Aerosol Optical Depth: An Observational and Modeling Study  

SciTech Connect

Cloud droplet effective radius (DER) is generally negatively correlated with aerosol optical depth (AOD) as a proxy of cloud condensation nuclei. In this study, cases of positive correlation were found over certain portions of the world by analyzing the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite products, together with a general finding that DER may increase or decrease with aerosol loading depending on environmental conditions. The slope of the correlation between DER and AOD is driven primarily by water vapor amount, which explains 70% of the variance in our study. Various potential artifacts that may cause the positive relation are investigated including water vapor swelling, partially cloudy, atmospheric dynamics, cloud three-dimensional (3-D) and surface influence effects. None seems to be the primary cause for the observed phenomenon, although a certain degree of influence exists for some of the factors. Analyses are conducted over seven regions around the world representing different types of aerosols and clouds. Only two regions show positive dependence of DER on AOD, near coasts of the Gulf of Mexico and South China Sea, which implies physical processes may at work. Using a 2-D spectral-bin microphysics Goddard Cumulus Ensemble model (GCE) which incorporated a reformulation of the Köhler theory, two possible physical mechanisms are hypothesized. They are related to the effects of slightly soluble organics (SSO) particles and giant CCNs. Model simulations show a positive correlation between DER and AOD, due to a decrease in activated aerosols with an increasing SSO content. Addition of a few giant CCNs also increases the DER. Further investigations are needed to fully understand and clarify the observed phenomenon.

Yuan, Tianle; Li, Zhanqing; Zhang, Renyi; Fan, Jiwen

2008-02-21T23:59:59.000Z

54

Terminal Velocities of Droplets and Crystals: Power Laws with Continuous Parameters over the Size Spectrum  

Science Conference Proceedings (OSTI)

This paper presents a unified treatment of cloud particle fall velocities for both liquid and crystalline cloud particles over the entire size range observed in the atmosphere. The fall velocity representation is formulated in terms of the Best (...

Vitaly I. Khvorostyanov; Judith A. Curry

2002-06-01T23:59:59.000Z

55

Comparing Ship-Track Droplet Sizes Inferred from Terra and Aqua MODIS Data  

Science Conference Proceedings (OSTI)

In this study of ship tracks, Moderate Resolution Imaging Spectroradiometer (MODIS) measurements from late-morning (Terra) and early-afternoon (Aqua) Earth Observing System platforms are analyzed in five separate geographically distributed cases ...

Burcu Kabatas; W. Paul Menzel; Ata Bilgili; Liam E. Gumley

2013-01-01T23:59:59.000Z

56

Parameterizing Size Distribution in Ice Clouds  

SciTech Connect

PARAMETERIZING SIZE DISTRIBUTIONS IN ICE CLOUDS David L. Mitchell and Daniel H. DeSlover ABSTRACT An outstanding problem that contributes considerable uncertainty to Global Climate Model (GCM) predictions of future climate is the characterization of ice particle sizes in cirrus clouds. Recent parameterizations of ice cloud effective diameter differ by a factor of three, which, for overcast conditions, often translate to changes in outgoing longwave radiation (OLR) of 55 W m-2 or more. Much of this uncertainty in cirrus particle sizes is related to the problem of ice particle shattering during in situ sampling of the ice particle size distribution (PSD). Ice particles often shatter into many smaller ice fragments upon collision with the rim of the probe inlet tube. These small ice artifacts are counted as real ice crystals, resulting in anomalously high concentrations of small ice crystals (D < 100 µm) and underestimates of the mean and effective size of the PSD. Half of the cirrus cloud optical depth calculated from these in situ measurements can be due to this shattering phenomenon. Another challenge is the determination of ice and liquid water amounts in mixed phase clouds. Mixed phase clouds in the Arctic contain mostly liquid water, and the presence of ice is important for determining their lifecycle. Colder high clouds between -20 and -36 oC may also be mixed phase but in this case their condensate is mostly ice with low levels of liquid water. Rather than affecting their lifecycle, the presence of liquid dramatically affects the cloud optical properties, which affects cloud-climate feedback processes in GCMs. This project has made advancements in solving both of these problems. Regarding the first problem, PSD in ice clouds are uncertain due to the inability to reliably measure the concentrations of the smallest crystals (D < 100 µm), known as the “small mode”. Rather than using in situ probe measurements aboard aircraft, we employed a treatment of ice cloud optical properties formulated in terms of PSD parameters in combination with remote measurements of thermal radiances to characterize the small mode. This is possible since the absorption efficiency (Qabs) of small mode crystals is larger at 12 µm wavelength relative to 11 µm wavelength due to the process of wave resonance or photon tunneling more active at 12 µm. This makes the 12/11 µm absorption optical depth ratio (or equivalently the 12/11 µm Qabs ratio) a means for detecting the relative concentration of small ice particles in cirrus. Using this principle, this project tested and developed PSD schemes that can help characterize cirrus clouds at each of the three ARM sites: SGP, NSA and TWP. This was the main effort of this project. These PSD schemes and ice sedimentation velocities predicted from them have been used to test the new cirrus microphysics parameterization in the GCM known as the Community Climate Systems Model (CCSM) as part of an ongoing collaboration with NCAR. Regarding the second problem, we developed and did preliminary testing on a passive thermal method for retrieving the total water path (TWP) of Arctic mixed phase clouds where TWPs are often in the range of 20 to 130 g m-2 (difficult for microwave radiometers to accurately measure). We also developed a new radar method for retrieving the cloud ice water content (IWC), which can be vertically integrated to yield the ice water path (IWP). These techniques were combined to determine the IWP and liquid water path (LWP) in Arctic clouds, and hence the fraction of ice and liquid water. We have tested this approach using a case study from the ARM field campaign called M-PACE (Mixed-Phase Arctic Cloud Experiment). This research led to a new satellite remote sensing method that appears promising for detecting low levels of liquid water in high clouds typically between -20 and -36 oC. We hope to develop this method in future research.

DeSlover, Daniel; Mitchell, David L.

2009-09-25T23:59:59.000Z

57

Pore size distribution and accessible pore size distribution in bituminous coals  

Science Conference Proceedings (OSTI)

The porosity and pore size distribution of coals determine many of their properties, from gas release to their behavior on carbonization, and yet most methods of determining pore size distribution can only examine a restricted size range. Even then, only accessible pores can be investigated with these methods. Small-angle neutron scattering (SANS) and ultra small-angle neutron scattering (USANS) are increasingly used to characterize the size distribution of all of the pores non-destructively. Here we have used USANS/SANS to examine 24 well-characterized bituminous and subbituminous coals: three from the eastern US, two from Poland, one from New Zealand and the rest from the Sydney and Bowen Basins in Eastern Australia, and determined the relationships of the scattering intensity corresponding to different pore sizes with other coal properties. The range of pore radii examinable with these techniques is 2.5 nm to 7 {micro}m. We confirm that there is a wide range of pore sizes in coal. The pore size distribution was found to be strongly affected by both rank and type (expressed as either hydrogen or vitrinite content) in the size range 250 nm to 7 {micro}m and 5 to 10 nm, but weakly in intermediate regions. The results suggest that different mechanisms control coal porosity on different scales. Contrast-matching USANS and SANS were also used to determine the size distribution of the fraction of the pores in these coals that are inaccessible to deuterated methane, CD{sub 4}, at ambient temperature. In some coals most of the small ({approx} 10 nm) pores were found to be inaccessible to CD{sub 4} on the time scale of the measurement ({approx} 30 min - 16 h). This inaccessibility suggests that in these coals a considerable fraction of inherent methane may be trapped for extended periods of time, thus reducing the effectiveness of methane release from (or sorption by) these coals. Although the number of small pores was less in higher rank coals, the fraction of total pores that was inaccessible was not rank dependent. In the Australian coals, at the 10 nm to 50 nm size scales the pores in inertinites appeared to be completely accessible to CD{sub 4}, whereas the pores in the vitrinite were about 75% inaccessible. Unlike the results for total porosity that showed no regional effects on relationships between porosity and coal properties, clear regional differences in the relationships between fraction of closed porosity and coal properties were found. The 10 to 50 nm-sized pores of inertinites of the US and Polish coals examined appeared less accessible to methane than those of the inertinites of Australian coals. This difference in pore accessibility in inertinites may explain why empirical relationships between fluidity and coking properties developed using Carboniferous coals do not apply to Australian coals.

Sakurovs, Richard [ORNL; He, Lilin [ORNL; Melnichenko, Yuri B [ORNL; Radlinski, Andrzej Pawell [ORNL; Blach, Tomasz P [ORNL

2012-01-01T23:59:59.000Z

58

Impact of the Vertical Variation of Cloud Droplet Size on the Estimation of Cloud Liquid Water Path and Rain Detection  

Science Conference Proceedings (OSTI)

Cloud droplet effective radius (DER) and liquid water path (LWP) are two key parameters for the quantitative assessment of cloud effects on the exchange of energy and water. Chang and Li presented an algorithm using multichannel measurements made ...

Ruiyue Chen; Fu-Lung Chang; Zhanqing Li; Ralph Ferraro; Fuzhong Weng

2007-11-01T23:59:59.000Z

59

Particle Size Distribution Model for Leaching Kinetics of Alumina  

Science Conference Proceedings (OSTI)

Presentation Title, Particle Size Distribution Model for Leaching Kinetics of Alumina. Author(s), Li Bao, Ting-an Zhang, Weimin Long, Anh V Nguyen, Guozhi Lv, ...

60

Influence of Powder Particle Size Distribution and Pressure on the ...  

Science Conference Proceedings (OSTI)

during HIP were determined as a function of applied pressure, temperature and initial powder particle size distribution for the nickel base superalloy. RENE 95.

Note: This page contains sample records for the topic "droplet size distribution" 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

Measuring the Raindrop Size Distribution, ARM's Efforts at Darwin...  

NLE Websites -- All DOE Office Websites (Extended Search)

Measuring the Raindrop Size Distribution, ARM's Efforts at Darwin and SGP Bartholomew, Mary Jane Brookhaven National Laboratory Category: Instruments ARM has purchased two impact...

62

Size-independent vs. size-dependent policies in scheduling heavy-tailed distributions  

E-Print Network (OSTI)

We study the problem of scheduling jobs on a two-machine distributed server, where the job size distribution is heavy-tailed. We focus on two distributions, for which we prove that the performance of the optimal size-independent ...

Nham, John (John T.)

2008-01-01T23:59:59.000Z

63

Bounds on distance distributions in codes of known size  

Science Conference Proceedings (OSTI)

We treat the problem of bounding components of the possible distance distributions of codes given the knowledge of their size and possibly minimum distance. Using the Beckner inequality from harmonic analysis, we derive upper bounds on distance distribution ...

A. E. Ashikhmin; G. D. Cohen; M. Krivelevich; S. N. Litsyn

2005-01-01T23:59:59.000Z

64

Examination of the ?–? Relation Suggested for Drop Size Distribution Parameters  

Science Conference Proceedings (OSTI)

Raindrop size distributions are often assumed to follow a three-parameter gamma distribution. Since rain intensity retrieval from radar observations is an underdetermined problem, there is great interest in finding physical correlations between ...

Dmitri N. Moisseev; V. Chandrasekar

2007-05-01T23:59:59.000Z

65

The Bias in Moment Estimators for Parameters of Drop Size Distribution Functions: Sampling from Exponential Distributions  

Science Conference Proceedings (OSTI)

The moment estimators frequently used to estimate parameters for drop size distribution (DSD) functions being “fitted” to observed raindrop size distributions are biased. Consequently, the fitted functions often do not represent well either the ...

Paul L. Smith; Donna V. Kliche

2005-08-01T23:59:59.000Z

66

Does Mixing Promote Cloud Droplet Growth?  

Science Conference Proceedings (OSTI)

A systematic examination of cloud droplet size spectra from the Cooperative Convective Precipitation Experiment (CCOPE) reveals no tendency for an increase in the maximum droplet size with increasing dilution or cloud age.

Ilga R. Paluch; Charles A. Knight

1986-09-01T23:59:59.000Z

67

Productivity and Firm Size Distribution: Evidence from India's Organized and Unorganized Manufacturing Sectors  

E-Print Network (OSTI)

Size Distribution - Credit, Electricity, and Labor Reg-Change in Employment Size Distribution Electricity SurplusChange in Employment Size Distribution Electricity Surplus

Nataraj, Shanthi

2010-01-01T23:59:59.000Z

68

Obtaining a bimodal grain size distribution via thermal means  

Science Conference Proceedings (OSTI)

Presentation Title, Obtaining a bimodal grain size distribution via thermal means ... manipulating thermal history, a family of bimodal grain size distributions may be formed. ... Mild Carbon Steel Quenche in Coconut Water, Fresh urine, Nigerian unadultrated up-wine, ... Multi-scale modeling of phase transformations in steels.

69

Optimal selection and sizing of distributed energy resources for distributed power systems  

Science Conference Proceedings (OSTI)

Optimal selection and sizing of distributed energy resources is an important research problem in the development of distributed power systems. This paper presents a methodology for optimal selection and sizing of distributed energy resources in integrated microgrids using the evolutionary strategy. Integrated microgrid is an innovative architecture in distributed power systems

Thillainathan Logenthiran; Dipti Srinivasan

2012-01-01T23:59:59.000Z

70

INITIAL PLANETESIMAL SIZES AND THE SIZE DISTRIBUTION OF SMALL KUIPER BELT OBJECTS  

SciTech Connect

The Kuiper Belt is a remnant from the early solar system and its size distribution contains many important constraints that can be used to test models of planet formation and collisional evolution. We show, by comparing observations with theoretical models, that the observed Kuiper Belt size distribution is well matched by coagulation models, which start with an initial planetesimal population with radii of about 1 km, and subsequent collisional evolution. We find that the observed size distribution above R {approx} 30 km is primordial, i.e., it has not been modified by collisional evolution over the age of the solar system, and that the size distribution below R {approx} 30 km has been modified by collisions and that its slope is well matched by collisional evolution models that use published strength laws. We investigate in detail the resulting size distribution of bodies ranging from 0.01 km to 30 km and find that its slope changes several times as a function of radius before approaching the expected value for an equilibrium collisional cascade of material strength dominated bodies for R {approx}< 0.1 km. Compared to a single power-law size distribution that would span the whole range from 0.01 km to 30 km, we find in general a strong deficit of bodies around R {approx} 10 km and a strong excess of bodies around 2 km in radius. This deficit and excess of bodies are caused by the planetesimal size distribution left over from the runaway growth phase, which left most of the initial mass in small planetesimals while only a small fraction of the total mass is converted into large protoplanets. This excess mass in small planetesimals leaves a permanent signature in the size distribution of small bodies that is not erased after 4.5 Gyr of collisional evolution. Observations of the small Kuiper Belt Object (KBO) size distribution can therefore test if large KBOs grew as a result of runaway growth and constrained the initial planetesimal sizes. We find that results from recent KBO occultation surveys and the observed KBO size distribution can be best matched by an initial planetesimal population that contained about equal mass per logarithmic mass bin in bodies ranging from 0.4 km to 4 km in radius. We further find that we cannot match the observed KBO size distribution if most of the planetesimal mass was contained in bodies that were 10 km in radius or larger simply because their resulting size distribution cannot be sufficiently depleted over 4.5 Gyr to match observations.

Schlichting, Hilke E. [UCLA, Department of Earth and Space Science, 595 Charles E. Young Drive East, Los Angeles, CA 90095 (United States); Fuentes, Cesar I.; Trilling, David E., E-mail: hilke@ucla.edu [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011 (United States)

2013-08-01T23:59:59.000Z

71

Statistical Tools for Drop Size Distributions: Moments and Generalized Gamma  

Science Conference Proceedings (OSTI)

Several problems associated with drop size distributions are treated. For rainfall rate R or radar reflectivity Z high powers of the drop diameters must be taken into account. This paper suggests methods to deal with the relevant moments and to ...

A. N. Aufder Maur

2001-02-01T23:59:59.000Z

72

Raindrop Size Distributions and the Radar Bright Band  

Science Conference Proceedings (OSTI)

The relationship between raindrop size distribution, measured with a disdrometer, and a radar parameter of the melting-layer bright band is investigated. The data, obtained in July 1993 in Switzerland, cover 120 h of precipitation. A good ...

A. Huggel; W. Schmid; A. Waldvogel

1996-10-01T23:59:59.000Z

73

The Measurement of Bubble-Size Distributions by Acoustical Backscatter  

Science Conference Proceedings (OSTI)

A multifrequency acoustical-backscatter technique is described for determining the size distribution of bubbles with radii between 8 and 130 µm. The method makes use of the resonance in the microbubbles and operates at six frequencies ranging ...

Svein Vagle; David M. Farmer

1992-10-01T23:59:59.000Z

74

Hailstone Size Distributions and Their Relationship to Storm Thermodynamics  

Science Conference Proceedings (OSTI)

From ten storms, 184 time-resolved hailstone samples have been collected at the ground in Alberta. For each of the samples collected, hailstone size and concentration were determined and a truncated exponential distribution was fitted to the ...

L. Cheng; M. English; R. Wong

1985-10-01T23:59:59.000Z

75

Statistical Characteristics of Raindrop Size Distribution in Southwest Monsoon Season  

Science Conference Proceedings (OSTI)

Raindrop size distribution (DSD) parameters are retrieved from dual-frequency (UHF and VHF) wind profiler measurements made at Gadanki, India, in a summer monsoon season. The convoluted UHF spectra are first corrected for vertical air motion and ...

N. V. P. Kirankumar; T. Narayana Rao; B. Radhakrishna; D. Narayana Rao

2008-02-01T23:59:59.000Z

76

Measurement of Raindrop Size Distributions Using a Small Doppler Radar  

Science Conference Proceedings (OSTI)

A small X-band bistatic Doppler radar originally developed for use in automated weather stations as a Precipitation Occurrence Sensor System (POSS) can also measure real time raindrop size distributions. In contrast to large-scale pulsed Doppler ...

Brian E. Sheppard

1990-04-01T23:59:59.000Z

77

Use of an Ultrasonic Sodar to Sense Raindrop Size Distributions  

Science Conference Proceedings (OSTI)

The design of a sodar that uses ultrasound to remotely sense drop size distributions in rainfall is described. The Doppler shift is proportional to a drop's terminal velocity and gives a measure of the drop diameter, whereas the intensity of ...

Stuart Bradley; Tracey Webb

2002-08-01T23:59:59.000Z

78

The Development of Drop Size Distributions in Light Rain  

Science Conference Proceedings (OSTI)

A model of rain development based on the quasi-stochastic coalescence equation and including the sedimentation of drops has been used to study the formation of drop size distributions in conditions of weak updraft. Comparisons with “box model” ...

I. Zawadzki; E. Monteiro; F. Fabry

1994-04-01T23:59:59.000Z

79

Some Factors Affecting the Size Distributions of Oceanic Bubbles  

Science Conference Proceedings (OSTI)

The effects of water temperature, dissolved gas saturation levels, and particulate concentrations on the size distribution of subsurface bubbles are investigated using numerical models. The input of bubbles, either at a constant rate in a “steady-...

S. A. Thorpe; P. Bowyer; D. K. Woolf

1992-04-01T23:59:59.000Z

80

Comparison of Polarimetric Radar Drop Size Distribution Retrieval Algorithms  

Science Conference Proceedings (OSTI)

Recently, two physically based algorithms, the “beta” (?) method and the “constrained-gamma” method, have been proposed for retrieving the governing parameters of the gamma drop size distribution (DSD) from polarimetric radar measurements. The ? ...

Edward A. Brandes; Guifu Zhang; J. Vivekanandan

2004-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Raindrop Size Distribution and Radar Parameters at Cape Verde  

Science Conference Proceedings (OSTI)

Precipitation measurement using passive or active microwaves from space- or ground-based radar involves hypotheses about the raindrop size distribution (DSD). A universal knowledge of DSD characteristics is needed. A 4-yr dataset collected with a ...

Armand Nzeukou; Henri Sauvageot; Abe Delfin Ochou; Cheikh Mouhamed Fadel Kebe

2004-01-01T23:59:59.000Z

82

Optimal Siting and Sizing of Distributed Energy Resources  

NLE Websites -- All DOE Office Websites (Extended Search)

Optimal Siting and Sizing of Distributed Energy Resources Optimal Siting and Sizing of Distributed Energy Resources Speaker(s): Johan Driesen Date: February 15, 2007 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Chris Marnay Ongoing changes in the operation of distribution grids call for a new way to plan grid modifications. This presentation gives an overview of possible methods of long-term planning for the deployment of Distributed Energy Resources (distributed generation, storage and controllable loads) in a given grid. The placement and sizing of the units have to be considered, making this a complex optimization problem with discrete and continuous variables. In the optimization problem, multiple objectives are often conflicting, e.g. minimal grid losses, maximal use of the resources and voltage stability. An evolutionary algorithm (genetic algorithms) is used

83

Comparison of Raindrop Size Distribution Measurements by Collocated Disdrometers  

Science Conference Proceedings (OSTI)

An impact-type Joss–Waldvogel disdrometer (JWD), a two-dimensional video disdrometer (2DVD), and a laser optical OTT Particle Size and Velocity (PARSIVEL) disdrometer (PD) were used to measure the raindrop size distribution (DSD) over a 6-month ...

Ali Tokay; Walter A. Petersen; Patrick Gatlin; Matthew Wingo

2013-08-01T23:59:59.000Z

84

Methods to determine the size distribution of airborne rhinovirus  

NLE Websites -- All DOE Office Websites (Extended Search)

Methods to determine the size distribution of airborne rhinovirus Methods to determine the size distribution of airborne rhinovirus Title Methods to determine the size distribution of airborne rhinovirus Publication Type Report Year of Publication 2004 Authors Russell, Marion L., Regine Goth-Goldstein, Michael G. Apte, and William J. Fisk Publisher Lawrence Berkeley National Laboratory Abstract About 50% of viral-induced respiratory illnesses are caused by the human rhinovirus (HRV). Prior research has demonstrated that rhinovirus infections can be transmitted via person-to-person contact and via inhalation of infectious aerosols. Measurements of the concentrations and sizes of bioaerosols are critical for research on building characteristics, aerosol transport, and mitigation measures. To detect airborne HRV, we developed a quantitative reverse transcription-coupled polymerase chain reaction (RT-PCR) assay and verified that this assay detects HRV in nasal lavage samples. A quantitation standard was used to determine the assay detection limit of 5 fg of HRV RNA with a linear range over 10,000-fold. This assay was used to quantify the size distribution of an artificially-produced HRV aerosol captured with an Andersen six-stage cascade impactor. In future studies, we hope to use the methods developed here to characterize the size distribution of naturally occurring viral-aerosols

85

MEASUREMENT OF ENTRAINED ORGANIC DROPLET SIZES AND TOTAL CONCENTRATION FOR AQUEOUS STREAMS FROM THE CAUSTIC-SIDE SOLVENT EXTRACTION PROCESS  

Science Conference Proceedings (OSTI)

The Modular Caustic-Side Solvent Extraction Unit (MCU) and the Salt Waste Processing Facility will remove radioactive cesium from Savannah River Site supernate wastes using an organic solvent system. Both designs include decanters and coalescers to reduce carryover of organic solvent droplets. Savannah River National Laboratory personnel conducted experimental demonstrations using a series of four 2-cm centrifugal contactors. They also examined organic carryover during operation of a CINC (Costner Industries Nevada Corporation) V-5 contactor under prototypical conditions covering the range of expected MCU operation. This report details the findings from those studies and the implications on design for the MCU.

Nash, C; Samuel Fink, S; Michael Restivo, M; Dan Burns, D; Wallace Smith, W; S Crump, S; Zane Nelson, Z; Thomas Peters, T; Fernando Fondeur, F; Michael Norato, M

2007-02-01T23:59:59.000Z

86

Dancing Droplets  

E-Print Network (OSTI)

Inspired by the observation of intricate and beautifully dynamic patterns generated by food coloring on clean glass slides, we have investigated the behavior of propylene glycol and water droplets on high energy surfaces. In this fluid dynamics video we show a range of interesting behaviors including long distance attraction, and chasing/fleeing upon contact. We present explanations for each of these behaviors including a mechanism for the long distance interactions based on vapor facilitated coupling. Finally we use our understanding to create several novel devices which: spontaneously align droplets, drive droplets in circles, cause droplets to bounce on a vertical surface, and passively sort droplets by surface tension. The simplicity of this system lends it particularly well to application as a toy model for physical systems with force fields and biological systems such as chemotaxis and motility.

Cira, Nate J

2013-01-01T23:59:59.000Z

87

Cloud Droplet Residual Particle Microphysics in Marine Stratocumulus Clouds Observed during the Monterey Area Ship Track Experiment  

Science Conference Proceedings (OSTI)

The effect of marine boundary layer pollution level (as determined by the aerosol particle number concentration) on the size distribution of aerosol particles that formed cloud droplets in marine stratiform clouds is examined. In situ ...

Elisabeth Öström; Kevin J. Noone; Robert A. Pockalny

2000-08-01T23:59:59.000Z

88

Method for measuring the size distribution of airborne rhinovirus  

NLE Websites -- All DOE Office Websites (Extended Search)

Method for measuring the size distribution of airborne rhinovirus Method for measuring the size distribution of airborne rhinovirus Title Method for measuring the size distribution of airborne rhinovirus Publication Type Conference Proceedings Year of Publication 2002 Authors Russell, Marion L., Regine Goth-Goldstein, Michael G. Apte, and William J. Fisk Conference Name Proceedings of the Indoor Air 2002 Conference, Monterey, CA Volume 1 Pagination 40-45 Publisher Indoor Air 2002, Santa Cruz, CA Abstract About 50% of viral-induced respiratory illnesses are caused by the human rhinovirus (HRV). Measurements of the concentrations and sizes of bioaerosols are critical for research on building characteristics, aerosol transport, and mitigation measures. We developed a quantitative reverse transcription-coupled polymerase chain reaction (RT-PCR) assay for HRV and verified that this assay detects HRV in nasal lavage samples. A quantitation standard was used to determine a detection limit of 5 fg of HRV RNA with a linear range over 1000-fold. To measure the size distribution of HRV aerosols, volunteers with a head cold spent two hours in a ventilated research chamber. Airborne particles from the chamber were collected using an Andersen Six-Stage Cascade Impactor. Each stage of the impactor was analyzed by quantitative RT-PCR for HRV. For the first two volunteers with confirmed HRV infection, but with mild symptoms, we were unable to detect HRV on any stage of the impactor

89

Free energy and size distributions of micelles in solution  

Science Conference Proceedings (OSTI)

This paper presents a new derivation of the free energy of micellar solutions. From this free energy a micelle size distribution can be calculated. By using a density functional model for the bulk contribution to the free energy and a simple approximation for the micelle (proper) contribution

P. S. Christopher; David W. Oxtoby

2003-01-01T23:59:59.000Z

90

Aerosol Size Distributions from Genetic Inversion of Polar Nephelometer Data  

Science Conference Proceedings (OSTI)

It is shown that genetic inversions can be used to recover lognormal aerosol size distributions from multiangle optical scattering cross-section data measured by a polar nephelometer at a wavelength of 0.532 ?m. The inversions can also be used to ...

B. R. Lienert; J. N. Porter; S. K. Sharma

2003-10-01T23:59:59.000Z

91

Particle-Size-Distribution of Nevada Test Site Soils  

SciTech Connect

The amount of each size particle in a given soil is called the particle-size distribution (PSD), and the way it feels to the touch is called the soil texture. Sand, silt, and clay are the three particle sizes of mineral material found in soils. Sand is the largest sized particle and it feels gritty; silt is medium sized and it feels floury; and clay is the smallest and if feels sticky. Knowing the particle-size distribution of a soil sample helps to understand many soil properties such as how much water, heat, and nutrients the soil will hold, how fast water and heat will move through the soil, and what kind of structure, bulk density and consistence the soil will have. Furthermore, the native particle-size distribution of the soil in the vicinity of ground zero of a nuclear detonation plays a major role in nuclear fallout. For soils that have a high-sand content, the near-range fallout will be relatively high and the far-range fallout will be relatively light. Whereas, for soils that have a high-silt and high-clay content, the near-range fallout will be significantly lower and the far-range fallout will be significantly higher. As part of a program funded by the Defense Threat Reduction Agency (DTRA), the Lawrence Livermore National Laboratory (LLNL) has recently measured the PSDs from the various major areas at the Nevada Test Site where atmospheric detonations and/or nuclear weapon safety tests were performed back in the 50s and 60s. The purpose of this report is to document those results.

Spriggs, G; Ray-Maitra, A

2007-09-17T23:59:59.000Z

92

Drop-size distribution for crosscurrent breakup of a liquid jet in a convective airstream  

E-Print Network (OSTI)

Experimental investigations have been completed in the study of a simulated fuel injector system implementing an airblast atomization process called a jet in a crossflow as the primary means of fuel atomization. To complete these studies an apparatus has been designed and constructed. A laser diffraction particle analyzer technique is used to spatially measure the spray Sauter-Mean Diameters. The Rosin-Rammler two parameter model is assumed for the droplet size distribution. Injection pressure for the injected liquid, distilled water, is held constant at 10.240 atm for the five different nozzle orifice diameters. A water rotameter is used to vary flowrates from 0.75 to 5.0 GPH and airflow Reynolds numbers are set at 50,000, 60,000, and 70,000 depending on the desired condition. SMD shows an increase in size for an increased distance from the top to the bottom of the test channel which is defined as the Y-Position from the orifice exit. The SMD growth rate decreases for increased water flowrates for a given airflow and orifice injector. For equal air-to-liquid ratios, overall SMD increases as the water flowrate and airflow Reynolds number combinations decrease. Overall SMD decreases for decreased air-to-liquid ratios. SMD decreases as the spray progresses downstream of the orifice exit in the direction of the airflow (X-Position) for a constant Y-Coordinate. A correlation of SMD-to-orifice diameter is determined to be as follows: [

Lyn, Gregory Michael

1994-01-01T23:59:59.000Z

93

Influence of Particle Size Distribution on Random Close Packing  

E-Print Network (OSTI)

The densest amorphous packing of rigid particles is known as random close packing. It has long been appreciated that higher densities are achieved by using collections of particles with a variety of sizes. The variety of sizes is often quantified by the polydispersity of the particle size distribution: the standard deviation of the radius divided by the mean radius. Several prior studies quantified the increase of the packing density as a function of polydispersity. Of course, a particle size distribution is also characterized by its skewness, kurtosis, and higher moments, but the influence of these parameters has not been carefully quantified before. In this work, we numerically generate many packings with different particle radii distributions, varying polydispersity and skewness independently of one another. We find two significant results. First, the skewness can have a significant effect on the packing density and in some cases can have a larger effect than polydispersity. Second, the packing fraction is relatively insensitive to the value of the kurtosis. We present a simple empirical formula for the value of the random close packing density as a function of polydispersity and skewness.

Kenneth W. Desmond; Eric R. Weeks

2013-03-19T23:59:59.000Z

94

Time Evolution of the Mutual Fund Size Distribution  

E-Print Network (OSTI)

We investigate the process of mutual fund growth both empirically and theoretically. The size of large mutual funds has a heavy tailed distribution that has been conjectured to be a power law; we investigate the data more carefully and show that it is better described by a log normal. To explain this we develop a stochastic growth model based on multiplicative growth, creation and annihilation. Under the simplifying assumption that these processes do not depend on fund size we obtain a time-dependent analytic solution of the model. The distribution evolves from a log normal into a power law only over long time scales, suggesting that log-normality comes about because the industry is still young and in a transient state due to its rapid growth in recent years. We make the model more realistic by taking into account size dependent effects, in particular the decay in the rates of diffusion and drift with increasing fund size. The resulting model is in good quantitative agreement with the data. Surprisingly, it a...

Schwarzkopf, Yonathan

2008-01-01T23:59:59.000Z

95

Universal Fluid Droplet Ejector - Energy Innovation Portal  

... deposition and cell-sorting applications Description A fluid ejector capable of producing micron sized droplets on demand is ... 5,943,075 (USA) ...

96

SIZE DISTRIBUTIONS OF SOLAR FLARES AND SOLAR ENERGETIC PARTICLE EVENTS  

Science Conference Proceedings (OSTI)

We suggest that the flatter size distribution of solar energetic proton (SEP) events relative to that of flare soft X-ray (SXR) events is primarily due to the fact that SEP flares are an energetic subset of all flares. Flares associated with gradual SEP events are characteristically accompanied by fast ({>=}1000 km s{sup -1}) coronal mass ejections (CMEs) that drive coronal/interplanetary shock waves. For the 1996-2005 interval, the slopes ({alpha} values) of power-law size distributions of the peak 1-8 A fluxes of SXR flares associated with (a) >10 MeV SEP events (with peak fluxes {>=}1 pr cm{sup -2} s{sup -1} sr{sup -1}) and (b) fast CMEs were {approx}1.3-1.4 compared to {approx}1.2 for the peak proton fluxes of >10 MeV SEP events and {approx}2 for the peak 1-8 A fluxes of all SXR flares. The difference of {approx}0.15 between the slopes of the distributions of SEP events and SEP SXR flares is consistent with the observed variation of SEP event peak flux with SXR peak flux.

Cliver, E. W. [Space Vehicles Directorate, Air Force Research Laboratory, Sunspot, NM 88349 (United States); Ling, A. G. [Atmospheric Environmental Research, Lexington, MA 02421 (United States); Belov, A. [IZMIRAN, Troitsk, Moscow Region 142190 (Russian Federation); Yashiro, S. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2012-09-10T23:59:59.000Z

97

The Bias and Error in Moment Estimators for Parameters of Drop Size Distribution Functions: Sampling from Gamma Distributions  

Science Conference Proceedings (OSTI)

This paper complements an earlier one that demonstrated the bias in the method-of-moments (MM) estimators frequently used to estimate parameters for drop size distribution (DSD) functions being “fitted” to observed raindrop size distributions. ...

Paul L. Smith; Donna V. Kliche; Roger W. Johnson

2009-10-01T23:59:59.000Z

98

The Spectral Energy Distribution of HH30 IRS: Constraining The Circumstellar Dust Size Distribution  

E-Print Network (OSTI)

We present spectral energy distribution (SED) models for the edge-on classical T Tauri star HH30 IRS that indicate dust grains have grown to larger than 50 microns within its circumstellar disk. The disk geometry and inclination are known from previous modeling of multiwavelength Hubble Space Telescope images and we use the SED to constrain the dust size distribution. Model spectra are shown for different circumstellar dust models: a standard ISM mixture and larger grain models. As compared to ISM grains, the larger dust grain models have a shallower wavelength dependent opacity. Models with the larger dust grains provide a good match to the currently available data, but mid and far-IR observations are required to more tightly constrain the dust size distribution. The accretion luminosity in our models is L_accdistributions that are simple power-law extensions (i.e., no exponential cutoff) yield acceptable fits to the optical/near-IR but too much emission at mm wavelengths and require larger disk masses. Such a simple size distribution would not be expected in an environment such as the disk of HH30 IRS, particularly over such a large range in grain sizes. However, its ability to adequately characterize the grain populations may be determined from more complete observational sampling of the SED in the mid to far-IR.

Kenneth Wood; Michael J. Wolff; J. E. Bjorkman; Barbara Whitney

2001-09-04T23:59:59.000Z

99

Measurements of Gas Bubble Size Distributions in Flowing Liquid Mercury  

Science Conference Proceedings (OSTI)

ABSTRACT Pressure waves created in liquid mercury pulsed spallation targets have been shown to induce cavitation damage on the target container. One way to mitigate such damage would be to absorb the pressure pulse energy into a dispersed population of small bubbles, however, measuring such a population in mercury is difficult since it is opaque and the mercury is involved in a turbulent flow. Ultrasonic measurements have been attempted on these types of flows, but the flow noise can interfere with the measurement, and the results are unverifiable and often unrealistic. Recently, a flow loop was built and operated at Oak Ridge National Labarotory to assess the capability of various bubbler designs to deliver an adequate population of bubbles to mitigate cavitation damage. The invented diagnostic technique involves flowing the mercury with entrained gas bubbles in a steady state through a horizontal piping section with a glass-window observation port located on the top. The mercury flow is then suddenly stopped and the bubbles are allowed to settle on the glass due to buoyancy. Using a bright-field illumination and a high-speed camera, the arriving bubbles are detected and counted, and then the images can be processed to determine the bubble populations. After using this technique to collect data on each bubbler, bubble size distributions were built for the purpose of quantifying bubbler performance, allowing the selection of the best bubbler options. This paper presents the novel procedure, photographic technique, sample visual results and some example bubble size distributions. The best bubbler options were subsequently used in proton beam irradiation tests performed at the Los Alamos National Laboratory. The cavitation damage results from the irradiated test plates in contact with the mercury are available for correlation with the bubble populations. The most effective mitigating population can now be designed into prototypical geometries for implementation into an actual SNS target.

Wendel, Mark W [ORNL; Riemer, Bernie [ORNL; Abdou, Ashraf A [ORNL

2012-01-01T23:59:59.000Z

100

Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx  

SciTech Connect

During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O{sub 3} and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate in agreement with the dominant pollution source being SO{sub 2} from Cu smelters and power plants. Pollutant layers in the free troposphere (FT) can be a result of emissions to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 C with dry air descending from the upper atmospheric and moist air having a BL contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (Dp > 100 nm) gives a linear relation up to a number concentration of {approx}150 cm{sup -3}, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that {approx}25% of aerosol in the PCASP size range are interstitial (not activated). One hundred and two constant altitude cloud transects were identified and used to determine properties of interstitial aerosol. One transect is examined in detail as a case study. Approximately 25 to 50% of aerosol with D{sub p} > 110 nm were not activated, the difference between the two approaches possibly representing shattered cloud droplets or unknown artifact. CDNC and interstitial aerosol were anti-correlated in all cloud transects, consistent with the occurrence of dry in-cloud areas due to entrainment or circulation mixing.

Kleinman, L.I.; Daum, P. H.; Lee, Y.-N.; Lewis, E. R.; Sedlacek III, A. J.; Senum, G. I.; Springston, S. R.; Wang, J.; Hubbe, J.; Jayne, J.; Min, Q.; Yum, S. S.; Allen, G.

2011-06-21T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Doppler Polarimetric Radar Measurements of the Gamma Drop Size Distribution of Rain  

Science Conference Proceedings (OSTI)

The conversion of radar reflections into rain intensities is dependent upon assumptions regarding the drop size distribution. The gamma drop size distribution contains three unknown parameters; the number of parameters that can be obtained ...

H. W. J. Russchenberg

1993-12-01T23:59:59.000Z

102

Synchronized droplet size measurements of intermittent coal-water slurry diesel sprays from an electronically-controlled accumulator fuel injection system  

E-Print Network (OSTI)

Experiments have been completed to characterize atomization of intermittent coal-water slurry sprays from an electronically controlled accumulator fuel injection system of a diesel fuel engine. A synchronized laser diffraction particle analyzer technique was used to measure the spray tip Sauter mean diameters (SMD). The Rosin-Rammler two parameter model was assumed for the droplet distribution. The measurements were made at the spray tip where laser obscuration was low and the chance of multiscattering bias was minimal. Coal-water slurry fuel with 50% coal loading by mass containing 5gm volume mean diameter coal particles was used. Injection pressures were ranged from 28 to II 0 MPa. Three different nozzle orifice diameters, 0.2, 0.4, and 0.6 mm, four axial measurement locations from 60 to 120 mm downstream of the nozzle tip were studied. Measurements were made for both pressurized (2.07 MPa, 300 psig) and unpressurized (ambient, 0 gage) chamber conditions. The spray tip SMD showed an increase with chamber gas density, and with axial measurement location, and showed a decrease with increasing injection pressure. The effect of nozzle orifice diameter on spray tip SMDs of completely developed sprays for such high pressure injections was found to be negligible. A regression equation for CWS-50 spray tip SMDs was determined as SMD = 0.279-P(inj).?702 r(amb) 2?85 x .521 where Pinj is the injection pressure in Mpa, r(amb) is the ambient density in kg/m3, and x is the axial measurement location downstream of the nozzle tip in mm. The equation shows very good agreement with the measured SMD data by having a Pearson correlation coefficient of 0.97. The results were also compared with previous SMD regression equations that were originally obtained for diesel fuel sprays.

Terracina, Dwayne Paul

1993-01-01T23:59:59.000Z

103

Estimation of Gamma Raindrop Size Distribution Parameters: Statistical Fluctuations and Estimation Errors  

Science Conference Proceedings (OSTI)

The gamma distribution is often used to characterize raindrop size distributions (DSDs). However, the estimation of measured raindrop distributions suffers from the shortcomings of statistical sampling errors, which become increasingly ...

Cécile Mallet; Laurent Barthes

2009-08-01T23:59:59.000Z

104

Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx  

SciTech Connect

During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O{sub 3} and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate. Pollutant layers in the free troposphere (FT) can be a result of emissions to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 C with dry air descending from the upper atmospheric and moist air having a boundary layer (BL) contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (D{sub p} > 100 nm) gives a linear relation up to a number concentration of {approx}150 cm{sup -3}, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that {approx}25 % of aerosol with D{sub p} > 100 nm are interstitial (not activated). A direct comparison of pre-cloud and in-cloud aerosol yields a higher estimate. Artifacts in the measurement of interstitial aerosol due to droplet shatter and evaporation are discussed. Within each of 102 constant altitude cloud transects, CDNC and interstitial aerosol were anti-correlated. An examination of one cloud as a case study shows that the interstitial aerosol appears to have a background, upon which is superimposed a high frequency signal that contains the anti-correlation. The anti-correlation is a possible source of information on particle activation or evaporation.

Kleinman L. I.; Daum, P. H.; Lee, Y.-N.; Lewis, E. R.; Sedlacek III, A. J.; Senum, G. I.; Springston, S. R.; Wang, J.; Hubbe, J.; Jayne, J.; Min, Q.; Yum, S. S.; Allen, G.

2012-01-04T23:59:59.000Z

105

EFFECTS OF SAMPLE SIZE ON CHARACTERIZATION OF WOOD-PARTICLE LENGTH DISTRIBUTION  

E-Print Network (OSTI)

EFFECTS OF SAMPLE SIZE ON CHARACTERIZATION OF WOOD-PARTICLE LENGTH DISTRIBUTION Quang V. Cao of sample size on fitting length distribution of wood particles used for manufacturing wood-based composites moments and the ability of the sample distributions to characterize the population represented

106

High-Resolution Measurement of Size Distributions of Asian Dust Using a Coulter Multisizer  

Science Conference Proceedings (OSTI)

A Coulter Multisizer, which is based on the electrical sensing zone (ESZ) or the Coulter principle, was used to measure the size distribution of Asian dust. Coulter Multisizer analysis provides high-resolution size measurements of water-insoluble ...

Hiroshi Kobayashi; Kimio Arao; Toshiyuki Murayama; Kengo Iokibe; Ryuji Koga; Masataka Shiobara

2007-02-01T23:59:59.000Z

107

The Sensitivity of Microwave Remote Sensing Observations of Precipitation to Ice Particle Size Distributions  

Science Conference Proceedings (OSTI)

This study investigates the effect of variable size distribution and density of precipitation ice particles on microwave brightness temperatures. For this purpose, a set of self-consistent relationships among rain rate, size parameters of an ...

Ralf Bennartz; Grant W. Petty

2001-03-01T23:59:59.000Z

108

Size Distribution of Coastal Aerosols: Effects of Local Sources and Sinks  

Science Conference Proceedings (OSTI)

Using aerosol optical depth as a function of wavelength obtained from ground-based multiwavelength radiometer observations, columnar size-distribution functions of aerosols have been derived. It has been found that the nature of the derived size-...

K. Krishna Moorthy; Prabha R. Nair; B. V. Krishna Murthy

1991-06-01T23:59:59.000Z

109

Modeling Raindrop Size Distribution and Z(R) Relations in the Western Mediterranean Area  

Science Conference Proceedings (OSTI)

This study shows the results of the modeling of drop size distributions (DSD) observed during a 2-yr study in Barcelona. Thirty-second individual sample collections of drop sizes and velocities were measured with an optical disdrometer and ...

Carlos Cerro; Bernat Codina; Joan Bech; Jeroni Lorente

1997-11-01T23:59:59.000Z

110

L-Moment Estimators as Applied to Gamma Drop Size Distributions  

Science Conference Proceedings (OSTI)

The traditional approach with experimental raindrop size data has been to use the method of moments in the fitting procedure to estimate the parameters for the raindrop size distribution function. However, the moment method is known to be biased ...

Donna V. Kliche; Paul L. Smith; Roger W. Johnson

2008-12-01T23:59:59.000Z

111

On the Form of Stationary Size Distributions Established by Coagulation and Sedimentation  

Science Conference Proceedings (OSTI)

In stationary solutions of the equations for nucleation, coagulation and sedimentation, the concentration of large particles falls off more strongly than any power of particle size. The tails of stationary size distributions established by these ...

Warren H. White

1983-07-01T23:59:59.000Z

112

Sensitivity of 5-cm Wavelength Polarimetric Radar Variables to Raindrop Axial Ratio and Drop Size Distribution  

Science Conference Proceedings (OSTI)

The sensitivity of polarimetric variables at a 5-cm wavelength to raindrop size and axial ratio is examined using T-matrix modeling of the scattering process for gamma raindrop size distributions fitted to tropical rainfall collected at Darwin, ...

T. D. Keenan; L. D. Carey; D. S. Zrni?; P. T. May

2001-03-01T23:59:59.000Z

113

Distributions of Raindrop Sizes and Fall Velocities in a Semiarid Plateau Climate: Convective versus Stratiform Rains  

Science Conference Proceedings (OSTI)

Joint size and fall velocity distributions of raindrops were measured with a Particle Size and Velocity (PARSIVEL) precipitation particle disdrometer in a field experiment conducted during July and August 2007 at a semiarid continental site ...

Shengjie Niu; Xingcan Jia; Jianren Sang; Xiaoli Liu; Chunsong Lu; Yangang Liu

2010-04-01T23:59:59.000Z

114

Electrical Mobility Spectrometer Using a Diethylene Glycol Condensation Particle Counter for Measurement of Aerosol Size Distributions Down to 1 nm  

Science Conference Proceedings (OSTI)

We report a new scanning mobility particle spectrometer (SMPS) for measuring number size distributions of particles down to {approx}1 nm mobility diameter. This SMPS includes an aerosol charger, a TSI 3085 nano differential mobility analyzer (nanoDMA), an ultrafine condensation particle counter (UCPC) using diethylene glycol (DEG) as the working fluid, and a conventional butanol CPC (the 'booster') to detect the small droplets leaving the DEG UCPC. The response of the DEG UCPC to negatively charged sodium chloride particles with mobility diameters ranging from 1-6 nm was measured. The sensitivity of the DEG UCPC to particle composition was also studied by comparing its response to positively charged 1.47 and 1.70 nm tetra-alkyl ammonium ions, sodium chloride, and silver particles. A high resolution differential mobility analyzer was used to generate the test particles. These results show that the response of this UCPC to sub-2 nm particles is sensitive to particle composition. The applicability of the new SMPS for atmospheric measurement was demonstrated during the Nucleation and Cloud Condensation Nuclei (NCCN) field campaign (Atlanta, Georgia, summer 2009). We operated the instrument at saturator and condenser temperatures that allowed the efficient detection of sodium chloride particles but not of air ions having the same mobility. We found that particles as small as 1 nm were detected during nucleation events but not at other times. Factors affecting size distribution measurements, including aerosol charging in the 1-10 nm size range, are discussed. For the charger used in this study, bipolar charging was found to be more effective for sub-2 nm particles than unipolar charging. No ion induced nucleation inside the charger was observed during the NCCN campaign.

Jiang, J.; Kuang, C.; Chen, M.; Attoui, M.; McMurry, P. H.

2011-02-01T23:59:59.000Z

115

On the size distribution of Atlantic tropical cyclones  

E-Print Network (OSTI)

The size of a tropical cyclone is known to vary considerably across storms, though little is understood about the environmental and internal factors that modulate it. Making use of newly available extended tropical cyclone ...

Emanuel, Kerry Andrew

116

On the Shape–Slope Relation of Drop Size Distributions in Convective Rain  

Science Conference Proceedings (OSTI)

The relation between the slope and shape parameters of the raindrop size distribution parameterized by a gamma distribution is examined. The comparison of results of a simple rain shaft model with an empirical relation based on disdrometer ...

Axel Seifert

2005-07-01T23:59:59.000Z

117

Natural Variations in the Analytical Form of the Raindrop Size Distribution  

Science Conference Proceedings (OSTI)

Empirical analyses are shown to imply variation in the shape or analytical form of the raindrop size distribution consistent with that observed experimentally and predicted theoretically. These natural variations in distribution shape are ...

Carlton W. Ulbrich

1983-10-01T23:59:59.000Z

118

Measurements of Aerosol Size Distributions in the Lower Troposphere over Northern Europe  

Science Conference Proceedings (OSTI)

Airborne measurements of particle size distributions were made at several altitudes within and above the mixing layer at sites near Ahlhorn and Meppen (West Germany), Rodby (Denmark), and Bruz (France). The distributions were measured over the ...

Bruce W. Fitch; Ted S. Cress

1981-10-01T23:59:59.000Z

119

Size Distributions and Dynamical Properties of Shallow Cumulus Clouds from Aircraft Observations and Satellite Data  

Science Conference Proceedings (OSTI)

In this paper aircraft observations of shallow cumulus over Florida during the Small Cumulus Microphysics Study (SCMS) are analyzed. Size distributions of cloud fraction, mass flux, and in-cloud buoyancy flux are derived. These distributions ...

Stefaan M. A. Rodts; Peter G. Duynkerke; Harm J. J. Jonker

2003-08-01T23:59:59.000Z

120

Retrieval of Raindrop Size Distribution from Simulated Dual-Frequency Radar Measurements  

Science Conference Proceedings (OSTI)

Observations of raindrop size distributions (DSDs) have validated the use of three-parameter distribution functions in representing the observed spectra. However, dual-frequency radar measurements are limited to retrieving two independent ...

S. Joseph Munchak; Ali Tokay

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Diagnosing the Intercept Parameter for Exponential Raindrop Size Distribution Based on Video Disdrometer Observations: Model Development  

Science Conference Proceedings (OSTI)

The exponential distribution N(D) = N0 exp(??D) with a fixed intercept parameter N0 is most commonly used to represent raindrop size distribution (DSD) in rainfall estimation and in single-moment bulk microphysics parameterization schemes. ...

Guifu Zhang; Ming Xue; Qing Cao; Daniel Dawson

2008-11-01T23:59:59.000Z

122

Supersaturation and Droplet Spectral Evolution in Fog  

Science Conference Proceedings (OSTI)

Droplet sizes, larger than expected, and transient water vapor supersaturations were measured in radiation fog. Nongradient turbulent mixing of saturated air parcels at different temperatures and the release of excess vapor by molecular diffusion ...

H. Gerber

1991-12-01T23:59:59.000Z

123

GA based energy loss minimization approach for optimal sizing & placement of distributed generation  

Science Conference Proceedings (OSTI)

Distributed Generators (DG) provide the lowest cost solution to handle low voltage or overload problems. In conjunction with such problems, a technique of energy saving is introduced by placement of distributed generation (DG) in distribution systems. ... Keywords: Distributed generation (DG), energy saving, genetic algorithms (GA), optimal sizing and placement

Deependra Singh; Devender Singh; K. S. Verma

2008-04-01T23:59:59.000Z

124

Investigation of Droplet Size Distributions and Drizzle Formation Using A New Trajectory Ensemble Model. Part II: Lucky Parcels  

Science Conference Proceedings (OSTI)

A novel trajectory ensemble model of the cloud-topped boundary layer containing 1340 Lagrangian parcels moving with a turbulent-like flow with the observed statistical properties was applied to investigate the formation of the microphysical ...

L. Magaritz; M. Pinsky; O. Krasnov; A. Khain

2009-04-01T23:59:59.000Z

125

The Characterization of Bimodal Droplet Size Distributions in the Ultrafiltration of Highly Concentrated Emulsions Applied to the Production of Biodiesel .  

E-Print Network (OSTI)

??A non-reactive model system comprising a highly concentrated and unstable oil-in-water emulsion was used to investigate the retention of oil by the membrane in producing… (more)

Falahati, Hamid

2010-01-01T23:59:59.000Z

126

Airship Measurements of Aerosol Size Distributions, Cloud Droplet Spectra, and Trace Gas Concentrations in the Marine Boundary Layer  

Science Conference Proceedings (OSTI)

The use of an airship as a platform to conduct atmospheric chemistry, aerosol, and cloud microphysical research is described, and results from demonstration flights made off the Oregon coast are presented. The slow speed of the airship makes it ...

G. M. Frick; W. A. Hoppel

1993-11-01T23:59:59.000Z

127

Sieveless particle size distribution analysis of particulate materials through computer vision  

Science Conference Proceedings (OSTI)

This paper explores the inconsistency of ''length-based separation'' by mechanical sieving of particulate materials with standard sieves, which is the standard method of particle size distribution (PSD) analysis. We observed inconsistencies of length-based ... Keywords: Biomass sieve analysis, Dimension, Image processing, ImageJ plugin, Particle size distribution, Physical property

C. Igathinathane; L. O. Pordesimo; E. P. Columbus; W. D. Batchelor; S. Sokhansanj

2009-05-01T23:59:59.000Z

128

Aerosol size distribution using Lidar data and a typical Lidar assembly  

Science Conference Proceedings (OSTI)

An algorithm is developed and detailed in this paper which determines atmospheric aerosol parameters such as backscatter and extinction coefficients, aerosol optical thickness, and the aerosol size distribution. The algorithm uses the power profile data ... Keywords: LIDAR system, aerosol optical depth, aerosol size distribution, remote sensing

Hamed Parsiani; Javier Mèndez

2008-11-01T23:59:59.000Z

129

Ant Colony System-Based Algorithm for Optimal Multi-stage Planning of Distribution Transformer Sizing  

Science Conference Proceedings (OSTI)

This paper proposes a stochastic optimization method, based on ant colony optimization, for the optimal choice of transformer sizes to be installed in a distribution network. This method is properly introduced to the solution of the optimal transformer ... Keywords: Ant Colony Optimization, Distribution Network Planning, Energy Loss Cost, Optimal Transformer Sizing, Thermal Loading, Transformers

Eleftherios I. Amoiralis; Pavlos S. Georgilakis; Marina A. Tsili; Antonios G. Kladas

2008-09-01T23:59:59.000Z

130

Experimental Characterization of BORAL® Pore Size and Volume Distributions  

Science Conference Proceedings (OSTI)

This study has measured pore size and pore volume of six different production batches of BORAL. The study included production lots that are known for being either blister prone or blister resistant under simulated canister wetting/vacuum drying conditions, or known to form edge blisters while in the spent-fuel pool. Additional production lots for which blister performance is unknown also were tested. Blisters in the cladding of BORAL, if large enough, can deform stainless steel walls in storage racks and...

2010-12-10T23:59:59.000Z

131

Journal of Molecular Catalysis A: Chemical 228 (2005) 299307 Complementary methods for cluster size distribution measurements  

E-Print Network (OSTI)

size distribution measurements: supported platinum nanoclusters in methane reforming catalysts J.V. All rights reserved. Keywords: Cluster size; SAXS; XAFS; HRTEM; Methane reforming 1. Introduction cluster size strongly influences the reactivity of surfaces for C H bond activation during CH4 steam

Iglesia, Enrique

132

What is the upper size limit for cosmopolitan distribution in free-living microorganisms?  

E-Print Network (OSTI)

What is the upper size limit for cosmopolitan distribution in free-living microorganisms? ABSTRACT distance apart) is used to try and answer the question `What is the upper size limit for cosmopolitan to 230 lm while the largest cosmopolitan species was 135 lm in size. Comparison of the testate

Brown, Richard

133

Bütschli dynamic droplet system  

Science Conference Proceedings (OSTI)

Dynamical oil-water systems such as droplets display lifelike properties and may lend themselves to chemical programming to perform useful work, specifically with respect to the built environment. We present Bütschli water-in-oil droplets as a model ... Keywords: Otto Bütschli, architecture, droplet, living technology, olive oil, origins of life

Rachel Armstrong; Martin Hanczyc

2013-10-01T23:59:59.000Z

134

Siting and sizing of distributed generation units using GA and OPF  

Science Conference Proceedings (OSTI)

This paper deals with the important task of finding the optimal siting and sizing of Distributed Generation (DG) units for a given distribution network so that the cost of active and reactive power generation can be minimized. The optimization technique ... Keywords: distributed generation, genetic alghorithm(GA), optimal power flow(OPF)

M. Hosseini Aliabadi; M. Mardaneh; B. Behbahan

2008-01-01T23:59:59.000Z

135

Physicochemical Characterization of Capstone Depleted Uranium Aerosols II: Particle Size Distributions as a Function of Time  

SciTech Connect

The Capstone Depleted Uranium (DU) Aerosol Study, which generated and characterized aerosols containing depleted uranium from perforation of armored vehicles with large-caliber DU penetrators, incorporated a sampling protocol to evaluated particle size distributions. Aerosol particle size distribution is an important parameter that influences aerosol transport and deposition processes as well as the dosimetry of the inhaled particles. These aerosols were collected on cascade impactor substrates using a pre-established time sequence following the firing event to analyze the uranium concentration and particle size of the aerosols as a function of time. The impactor substrates were analyzed using beta spectrometry, and the derived uranium content of each served as input to the evaluation of particle size distributions. Activity median aerodynamic diameters (AMADs) of the particle size distributions were evaluated using unimodal and bimodal models. The particle size data from the impactor measurements was quite variable. Most size distributions measured in the test based on activity had bimodal size distributions with a small particle size mode in the range of between 0.2 and 1.2 um and a large size mode between 2 and 15 um. In general, the evolution of particle size over time showed an overall decrease of average particle size from AMADs of 5 to 10 um shortly after perforation to around 1 um at the end of the 2-hr sampling period. The AMADs generally decreased over time because of settling. Additionally, the median diameter of the larger size mode decreased with time. These results were used to estimate the dosimetry of inhaled DU particles.

Cheng, Yung-Sung; Kenoyer, Judson L.; Guilmette, Raymond A.; Parkhurst, MaryAnn

2009-03-01T23:59:59.000Z

136

The dune size distribution and scaling relations of barchan dune fields  

E-Print Network (OSTI)

Barchan dunes emerge as a collective phenomena involving the generation of thousands of them in so called barchan dune fields. By measuring the size and position of dunes in Moroccan barchan dune fields, we find that these dunes tend to distribute uniformly in space and follow an unique size distribution function. We introduce an analyticalmean-field approach to show that this empirical size distribution emerges from the interplay of dune collisions and sand flux balance, the two simplest mechanisms for size selection. The analytical model also predicts a scaling relation between the fundamental macroscopic properties characterizing a dune field, namely the inter-dune spacing and the first and second moments of the dune size distribution.

Orencio Durán; Veit Schwämmle; Pedro G. Lind; Hans J. Herrmann

2007-01-16T23:59:59.000Z

137

Measuring droplet impact with piezoelectric film  

E-Print Network (OSTI)

The objective of this research was to develop a measurement system for determining droplet impact in the field with piezoelectric film. The piezoelectric film generates an output signal when it is deformed. The signals are analyzed with a data acquisition system (a computer with two high speed boards). Eight piezoelectric films were calibrated in the laboratory. Each film was calibrated by releasing various water droplet sizes from different heights. The signal output of film was then related to the kinetic energy of the droplet. The maximum droplet diameter generated was 5.6 mm, and the maximum height used was 4.59 m. To simulate a kinetic energy for larger droplets and higher elevations, a solid particle with 9.9 mm diameter and 0.5 gram mass was used. The results show that, in general, the output of piezoelectfic film responds linearly to kinetic energy. However, due to the size of the film used and deformation of large droplets upon impact, the output become non-linear and may be represented by Y=ax1 +bx2 +cx1cx2+dx12x2+ex13x2 + where, y = sensor output a, b, c, d, e = constants which depend on the characteristics of the film X1 = the kinetic energy X2 = I for the solid particle X2= 0 for water drops The measurement system was tested in the field. The results showed that this system could be used to measure droplet impact force at different places on plants.

Basahi, Jalal M. Al-Badry M.

1993-01-01T23:59:59.000Z

138

Dust Grain-Size Distributions From MRN to MEM  

E-Print Network (OSTI)

Employing the Maximum Entropy Method algorithm, we fit interstellar extinction measurements which span the wavelength range 0.125-3 micron. We present a uniform set of MEM model fits, all using the same grain materials, optical constants and abundance constraints. In addition, we are taking advantage of improved UV and IR data and better estimates of the gas-to-dust ratio. The model fits cover the entire range of extinction properties that have been seen in the Galaxy and the Magellanic Clouds. The grain models employed for this presentation are the simplistic homogeneous spheres models (i.e., Mathis, Rumpl, & Nordsieck 1977) with two (graphite, silicate) or three (graphite, silicate, amorphous carbon) components. Though such usage is only a first step, the results do provide interesting insight into the use of grain size as a diagnostic of dust environment. We find that the SMC Bar extinction curve cannot be fit using carbon grains alone. This is a challenge to the recent observational result indicating little silicon depletion in the SMC.

Geoffrey C. Clayton; Michael J. Wolff; Ulysses J. Sofia; K. D. Gordon; K. A. Misselt

2003-01-24T23:59:59.000Z

139

Retrieval of Raindrop Size Distributions Using Two Doppler Wind Profilers: Model Sensitivity Testing  

Science Conference Proceedings (OSTI)

The behavior of precipitation is of great importance in obtaining a better understanding of heat transport estimates and global processes in the atmosphere. This paper discusses improvements in an earlier raindrop size distribution model that ...

W. B. Maguire II; S. K. Avery

1994-12-01T23:59:59.000Z

140

Variability of Raindrop Size Distributions in a Squall Line and Implications for Radar Rainfall Estimation  

Science Conference Proceedings (OSTI)

The intrastorm variability of raindrop size distributions as a source of uncertainty in single-parameter and dual-parameter radar rainfall estimates is studied using time series analyses of disdrometer observations. Two rain-rate (R) estimators ...

Remko Uijlenhoet; Matthias Steiner; James A. Smith

2003-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Relationships between the Raindrop Size Distribution and Properties of the Environment and Clouds Inferred from TRMM  

Science Conference Proceedings (OSTI)

Raindrop size distribution (DSD) retrievals from two years of data gathered by the Tropical Rainfall Measuring Mission (TRMM) satellite and processed with a combined radar–radiometer algorithm over the oceans equatorward of 35° are examined for ...

S. Joseph Munchak; Christian D. Kummerow; Gregory Elsaesser

2012-04-01T23:59:59.000Z

142

The Modification of Joint Size-Charge Distribution in Rain. Part II: Computations Involving Partial Coalescence  

Science Conference Proceedings (OSTI)

Raindrop collisional breakup is included in a model of joint size-charge distribution development. Consistent with experimental observations the model includes a finite filament (joining separating drops) that upon rupture produces charged ...

S. G. Bradley; C. D. Stow

1984-10-01T23:59:59.000Z

143

A Preliminary Analysis of Spatial Variability of Raindrop Size Distributions during Stratiform Rain Events  

Science Conference Proceedings (OSTI)

The spatial variability of raindrop size distributions (DSDs) and precipitation fields is investigated utilizing disdrometric measurements from the four Precipitation Occurrence Sensor Systems (POSS) and radar reflectivity fields from S-band dual-...

Choong Ke Lee; Gyu Won Lee; Isztar Zawadzki; Kyung-Eak Kim

2009-02-01T23:59:59.000Z

144

Wind-Induced Error of Raindrop Size Distribution Measurement Using a Two-Dimensional Video Disdrometer  

Science Conference Proceedings (OSTI)

The authors investigate a disdrometer that provides information on raindrop size distribution, terminal velocity, and shape using video imaging technology. Two video cameras are enclosed in a large box and provide images of the passing drops. The ...

Vladislav Nešpor; Witold F. Krajewski; Anton Kruger

2000-11-01T23:59:59.000Z

145

Optimal Determination of Parameters for Gamma-Type Drop Size Distributions Based on Moments  

Science Conference Proceedings (OSTI)

Measured raindrop size distributions are often approximated by analytical functions. The parameters determining such functions are usually derived from measured data. This procedure can suffer from various uncertainties. The most important of ...

Jan Handwerker; Winfried Straub

2011-04-01T23:59:59.000Z

146

Air Entrainment Processes and Bubble Size Distributions in the Surf Zone  

Science Conference Proceedings (OSTI)

A new optical instrument was deployed in the surf zone in a trial experiment to measure bubble size distributions and visualize air entrainment and bubble formation mechanisms within breaking surf. Images of bubbles and the evolving air–water ...

Grant B. Deane; M. Dale Stokes

1999-07-01T23:59:59.000Z

147

Polarimetric Radar Rain Estimation through Retrieval of Drop Size Distribution Using a Bayesian Approach  

Science Conference Proceedings (OSTI)

This study proposes a Bayesian approach to retrieve raindrop size distributions (DSDs) and to estimate rainfall rates from radar reflectivity in horizontal polarization ZH and differential reflectivity ZDR. With this approach, the authors apply a ...

Qing Cao; Guifu Zhang; Edward A. Brandes; Terry J. Schuur

2010-05-01T23:59:59.000Z

148

A Comparison of Techniques to Estimate Vertical Air Motions and Raindrop Size Distributions  

Science Conference Proceedings (OSTI)

Doppler velocity spectra collected at vertical incidence contain information on vertical air motions and drop-size distributions with high spatial and temporal resolution. In the past, the computational interdependence between vertical air ...

Karen L. Sangren; Peter S. Ray; Gene B. Walker

1984-06-01T23:59:59.000Z

149

Raindrop Size Distribution and Radar Parameters in Coastal Tropical Rain Systems of Northeastern Brazil  

Science Conference Proceedings (OSTI)

A dataset on raindrop size distribution (DSD) gathered in a coastal site of the Alagoas state in northeastern Brazil is used to analyze some differences between continental and maritime rainfall parameters. The dataset is divided into two subsets. ...

Ricardo Sarmento Tenório; Marcia Cristina da Silva Moraes; Henri Sauvageot

2012-11-01T23:59:59.000Z

150

Effects of Drop-Size-Distribution Truncation on Computer Simulations of Dual-Measurement Radar Methods  

Science Conference Proceedings (OSTI)

An investigation is made of the effects of truncating the raindrop-size distribution at minimum and maximum diameters on the results of computer simulations of dual-measurement radar methods. The dual-measurement methods investigated include ...

Carlton W. Ulbrich

1992-07-01T23:59:59.000Z

151

Wavenumber Analysis of Azimuthally Distributed Data: Assessing Maximum Allowable Gap Size  

Science Conference Proceedings (OSTI)

Performing wavenumber decomposition on azimuthally distributed data such as those in tropical cyclones can be challenging when data gaps exist in the signal. In the literature, ad hoc approaches are found to determine maximum gap size beyond which ...

Sylvie Lorsolo; Altu? Aksoy

2012-06-01T23:59:59.000Z

152

A Free-Flooding Acoustical Resonator for Measurement of Bubble Size Distributions  

Science Conference Proceedings (OSTI)

An instrument for the measurement of bubble size distributions is described. The sensing element exploits the free-flooding resonator design of Medwin with modifications to overcome the limitations in the original implementation, especially those ...

David M. Farmer; Svein Vagle; A. Donald Booth

1998-10-01T23:59:59.000Z

153

The Use of Direct Observations over the Aerosol Particle Size Distribution for Inverting Lidar Data  

Science Conference Proceedings (OSTI)

The work is concerned with the inversion of horizontal lidar data into the aerosol particle size distribution (APSD). The aerosol is assumed to consist of spherical particles of continental and oceanic origin. The particular refraction index is ...

Kusiel S. Shifrin; Ilia G. Zolotov

2003-10-01T23:59:59.000Z

154

A Probabilistic View on the Rain Drop Size Distribution Modeling: a Physical Interpretation of Rain Microphysics  

Science Conference Proceedings (OSTI)

The Rain Drop Size Distribution (RDSD) is defined as the relative frequency of raindrops per given diameter in a volume. This paper describes a mathematically-consistent modeling of the RDSD drawing on probability theory. It is shown that this ...

Francisco J. Tapiador; Ziad S. Haddad; Joe Turk

155

Functional Fits to Some Observed Drop Size Distributions and Parameterization of Rain  

Science Conference Proceedings (OSTI)

A data sample of optical spectrometer measurements that were obtained in two tropical cyclones is analyzed. The resultant drop size distributions are normalized and their shape is found to exhibit some curvature-departure from exponentiality. ...

Paul T. Willis

1984-05-01T23:59:59.000Z

156

Modeling the Variability of Drop Size Distributions in Space and Time  

Science Conference Proceedings (OSTI)

The information on the time variability of drop size distributions (DSDs) as seen by a disdrometer is used to illustrate the structure of uncertainty in radar estimates of precipitation. Based on this, a method to generate the space–time ...

Gyu Won Lee; Alan W. Seed; Isztar Zawadzki

2007-06-01T23:59:59.000Z

157

Errors in Estimating Raindrop Size Distribution Parameters Employing Disdrometer and Simulated Raindrop Spectra  

Science Conference Proceedings (OSTI)

There have been debates and differences of opinion over the validity of using drop size distribution (DSD) models to characterize precipitation microphysics and to retrieve DSD parameters from multiparameter radar measurements. In this paper, ...

Qing Cao; Guifu Zhang

2009-02-01T23:59:59.000Z

158

An Investigation of the Slope–Shape Relation for Gamma Raindrop Size Distribution  

Science Conference Proceedings (OSTI)

The gamma drop size distribution (DSD) has been widely used in the meteorological community for years to model observed DSD. It has been found that the relation between the slope (?) and shape (?) parameters of the gamma DSD can be empirically ...

Yen-Hsyang Chu; Ching-Lun Su

2008-10-01T23:59:59.000Z

159

Dust negative ion acoustic shock waves considering dust size distribution effect  

Science Conference Proceedings (OSTI)

A multi-ion dusty plasma containing hot isothermal electrons, ions (light positive ions and heavy negative ions), and extremely and negatively charged dust grains is studied in the present paper. The dust negative ion acoustic shock waves have been investigated by employing the reductive perturbation method. How the dust size distribution affects the height and the thickness of the nonlinear shock wave is studied. It is noted that the different dust size distribution has different shock wave form and different moving speed.

Ma Yirong; Wang Canglong; Zhang Jianrong; Sun Jianan; Duan Wenshan [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070, China and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yang Lei [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)

2012-11-15T23:59:59.000Z

160

ARM - Evaluation Product - Droplet Number Concentration Value-Added Product  

NLE Websites -- All DOE Office Websites (Extended Search)

ProductsDroplet Number Concentration Value-Added ProductsDroplet Number Concentration Value-Added Product Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Evaluation Product : Droplet Number Concentration Value-Added Product 2005.01.01 - 2010.12.30 Site(s) SGP General Description Cloud droplet number concentration is an important factor in understanding aerosol-cloud interactions. As aerosol concentration increases, it is expected that droplet number concentration, Nd, will increase and droplet size decrease, for a given liquid water path (Twomey 1977), which will greatly affect cloud albedo as smaller droplets reflect more shortwave radiation. However, the magnitude and variability of these processes under different environmental conditions is still uncertain. McComiskey et al.

Note: This page contains sample records for the topic "droplet size distribution" 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

The Shape–Slope Relation in Observed Gamma Raindrop Size Distributions: Statistical Error or Useful Information?  

Science Conference Proceedings (OSTI)

The three-parameter gamma distribution n(D) = N0Dµ exp(–?D) is often used to characterize a raindrop size distribution (DSD). The parameters µ and ? correspond to the shape and slope of the DSD. If µ and ? are related to one another, as recent ...

Guifu Zhang; J. Vivekanandan; Edward A. Brandes; Robert Meneghini; Toshiaki Kozu

2003-08-01T23:59:59.000Z

162

The Effects of Drop Size Distribution Truncation on Rainfall Integral Parameters and Empirical Relations  

Science Conference Proceedings (OSTI)

A description is given of a method of estimating the effects of truncating the raindrop size distribution (DSD) at lower and upper drop diameters Dmin and Dmax which assumes that the DSD can be approximated by a gamma distribution (including the ...

Carlton W. Ulbrich

1985-06-01T23:59:59.000Z

163

The E ect of Heavy-Tailed Job Size Distributions on Computer System Design.  

E-Print Network (OSTI)

The E ect of Heavy-Tailed Job Size Distributions on Computer System Design. Mor Harchol-Balter Laboratory for Computer Science MIT, NE43-340 Cambridge, MA 02139 harchol@theory.lcs.mit.edu Abstract Heavy physical phenomena to sociological phenomena. Recently heavy-tailed distributions have been discovered

Harchol-Balter, Mor

164

A POSSIBLE DIVOT IN THE SIZE DISTRIBUTION OF THE KUIPER BELT'S SCATTERING OBJECTS  

Science Conference Proceedings (OSTI)

Via joint analysis of a calibrated telescopic survey, which found scattering Kuiper Belt objects, and models of their expected orbital distribution, we explore the scattering-object (SO) size distribution. Although for D > 100 km the number of objects quickly rise as diameters decrease, we find a relative lack of smaller objects, ruling out a single power law at greater than 99% confidence. After studying traditional ''knees'' in the size distribution, we explore other formulations and find that, surprisingly, our analysis is consistent with a very sudden decrease (a divot) in the number distribution as diameters decrease below 100 km, which then rises again as a power law. Motivated by other dynamically hot populations and the Centaurs, we argue for a divot size distribution where the number of smaller objects rises again as expected via collisional equilibrium. Extrapolation yields enough kilometer-scale SOs to supply the nearby Jupiter-family comets. Our interpretation is that this divot feature is a preserved relic of the size distribution made by planetesimal formation, now ''frozen in'' to portions of the Kuiper Belt sharing a ''hot'' orbital inclination distribution, explaining several puzzles in Kuiper Belt science. Additionally, we show that to match today's SO inclination distribution, the supply source that was scattered outward must have already been vertically heated to the of order 10 Degree-Sign .

Shankman, C.; Gladman, B. J. [Department of Physics and Astronomy, University of British Columbia, 6224 Agriculture Road, Vancouver, BC V6T 1Z1 (Canada); Kaib, N. [Department of Physics and Astronomy, Queens University (Canada); Kavelaars, J. J. [National Research Council of Canada, Victoria, BC V9E 2E7 (Canada); Petit, J. M. [Institut UTINAM, CNRS-Universite de Franche-Comte, Besancon (France)

2013-02-10T23:59:59.000Z

165

Patterning droplets with durotaxis  

E-Print Network (OSTI)

Numerous cell-types have shown a remarkable ability to detect and move along gradients in stiffness of an underlying substrate -- a process known as durotaxis. The mechanisms underlying durotaxis are still unresolved, but generally believed to involve active sensing and locomotion. Here, we show that simple liquid droplets also undergo durotaxis. By modulating substrate stiffness, we obtain fine control of droplet position on soft, flat substrates. Unlike other control mechanisms, droplet durotaxis works without imposing chemical, thermal, electrical or topographical gradients. This enables a new approach to large-scale droplet patterning and is potentially useful for many applications, such as microfluidics, thermal control and microfabrication.

Robert W. Style; Yonglu Che; Su Ji Park; Byung Mook Weon; Jung Ho Je; Callen Hyland; Guy K. German; Michael Power; Larry A. Wilen; John S. Wettlaufer; Eric R. Dufresne

2013-04-15T23:59:59.000Z

166

Measurements of Aerosol Charge and Size Distribution for Graphite, Gold, Palladium, and Silver Nanoparticles  

Science Conference Proceedings (OSTI)

The role of charge on aerosol evolution and hence the nuclear source term has been an issue of interest, and there is a need for both experimental techniques and modeling for quantifying this role. Our focus here is on further exploration of a tandem differential mobility analyzer (TDMA) technique to simultaneously measure both the size and charge (positive, negative and neutral) dependent aerosol distributions. We have generated graphite, gold, silver, and palladium nanoparticles (aerosol) using a spark generator. We measure the electrical mobility-size distributions for these aerosols using a TDMA, and from these data we deduce the full charge-size distributions. We observe asymmetry in the particle size distributions for negative and positive charges. This asymmetry could have a bearing on the dynamics of charged aerosols, indicating that the assumption of symmetry for size distributions of negatively and positively charged particles in source term simulations may not be always appropriate. Also, the experimental technique should find applications in measurements of aerosol rate processes that are affected by both particle charge and size (e.g. coagulation, deposition, resuspension), and hence in modeling and simulation of the nuclear source term.

Simones, Matthew P.; Gutti, Veera R.; Meyer, Ryan M.; Loyalka, Sudarshan K.

2011-11-01T23:59:59.000Z

167

Particle size distributions of ground corn and DDGS from dry grind processing  

E-Print Network (OSTI)

ABSTRACT. Ethanol production has increased in the past decade as a result of growth in the dry grind industry. In the dry grind process, the first step is grinding of corn. The particle size of the resulting ground corn can affect the fermentation process and the particle size of dried distillers ’ grains with solubles (DDGS), a coproduct of dry grind processing. Few data are available that characterize particle size distributions of ground corn or DDGS. The objective was to determine particle size distributions of ground corn and DDGS. Samples of ground corn and DDGS were obtained from nine dry grind plants; particle size distribution, geometric mean diameter (dgw) and geometric standard deviation (Sgw) were determined. The dgw of ground corn and of DDGS were not different among processing plants. The overall mean dgw of ground corn was not different from that of DDGS. Most of the ground corn (80 g/100 g) and DDGS (70 g/100 g) were recovered in the three largest particle size categories. The particle size distributions of ground corn were not correlated (r Corn, DDGS, Distillers dried grains with solubles, Ethanol. Corn is processed into ethanol by one of two major processes: dry grinding or wet milling. Wet milling is more complex than dry grinding because fiber and germ components are separated; this requires considerable equipment and capital. In the dry grind process,

K. D. Rausch; R. L. Belyea; M. R. Ellersieck; V. Singh; D. B. Johnston; M. E. Tumbleson

2005-01-01T23:59:59.000Z

168

Grain size distributions and photo-electric heating in ionized media  

E-Print Network (OSTI)

Ever since the pioneering study of Spitzer, it has been widely recognized that grains play an important role in the heating and cooling of photo-ionized environments. A detailed code is necessary to model grains in a photo-ionized medium. In this paper we will use the spectral synthesis code Cloudy for this purpose. The grain model of this code has recently undergone a comprehensive upgrade. Part of this is the newly developed hybrid grain charge model, which will be described in detail. This model allows discrete charge states of very small grains to be modelled accurately while simultaneously avoiding the overhead of fully resolving the charge distribution of large grains, thus making the model both accurate and computationally efficient. A comprehensive comparison with the fully resolved charge state models of Weingartner & Draine (2001) shows that the agreement is very satisfactory for realistic size distributions. The effect of the grain size distribution on the line emission from photo-ionized regions is studied by taking standard models for an H II region and a planetary nebula and adding a dust component to the models with varying grain size distributions. A comparison of the models shows that varying the size distribution has a dramatic effect on the emitted spectrum, and affects the ionization balance as well. These results clearly demonstrate that the grain size distribution is an important parameter in photo-ionization models.

P. A. M. van Hoof; J. C. Weingartner; P. G. Martin; K. Volk; G. J. Ferland

2004-02-16T23:59:59.000Z

169

Standard Test Method for Particle Size Distribution of Alumina or Quartz Powders by Electrical Sensing Zone Technique  

E-Print Network (OSTI)

Standard Test Method for Particle Size Distribution of Alumina or Quartz Powders by Electrical Sensing Zone Technique

American Society for Testing and Materials. Philadelphia

1992-01-01T23:59:59.000Z

170

Experimental Determination of Droplet Impaction on Canopy Components of Balsam Fir  

Science Conference Proceedings (OSTI)

The capture efficiencies of balsam fir [Abies balsamea (L.) Mill] canopy components for monodisperse glycerin droplets were measured in a low-speed wind tunnel. Droplets were produced at sizes and wind speeds typical of cloudy conditions in a ...

Philip G. Thorne; Gary M. Lovett; William A. Reiners

1982-10-01T23:59:59.000Z

171

Laboratory Studies of Scattering Properties of Polluted Cloud Droplets: Implications for FSSP Measurements  

Science Conference Proceedings (OSTI)

Laboratory experiments were conducted in the Mainz vertical wind tunnel to study the effects of pollutants dissolved or suspended in cloud droplets on the droplet size measurements of a Forward Scattering Spectrometer Probe (FSSP). The FSSP is a ...

Karoline Diehl; Günter Huber; Subir K. Mitra; Manfred Wendisch

2008-10-01T23:59:59.000Z

172

An Aggregate Model for the Particle Size Distribution in Saturn's Rings  

E-Print Network (OSTI)

Saturn's rings are known to consist of a large number of water ice particles. They form a flat disk, as the result of an interplay of angular momentum conservation and the steady loss of energy in dissipative particle collisions. For particles in the size range from a few centimeters to about a few meters a power law distribution of radii r^(-q), with q = 3, is implied by the light scattering properties of the rings. In contrast, for larger sizes the distribution drops steeply with increasing r. It has been suggested that this size distribution may arise from a balance between aggregation and fragmentation of ring particles, but to date neither the power-law dependence, nor the upper size-cutoff have been explained or quantified within a unique theory. Here we present a new kinetic model for the collisional evolution of the size distribution and show that the exponent q is expected to be constrained to the interval 2.75 < q < 3.5. An exponential cutoff towards larger particle sizes establishes naturally...

Brilliantov, Nikolai; Hayakawa, Hisao; Bodrova, Anna; Spahn, Frank; Schmidt, Juergen

2013-01-01T23:59:59.000Z

173

EVOLUTION OF SIZE DISTRIBUTION OF ICY GRAINS BY SUBLIMATION AND CONDENSATION  

SciTech Connect

In the outer part of a protoplanetary disk, dust grains consist of silicate core covered by an ice mantle. A temporal heating event in the disk results in sublimation of the ice mantle. After the end of the heating event, as the temperature decreases, H{sub 2}O molecules recondense on the surface of the dust grain. Ultimately, the dust grain is covered by an ice mantle. Because the equilibrium vapor pressure on the grain surface decreases with the grain size, a large grain grows faster than a small grain. As a result, the size of an icy dust grain changes as a result of the heating event. The change in size also affects the mechanical properties of the dust aggregates formed by the icy grains. In this paper, we investigated the evolution of the size distribution of icy dust grains during sublimation and condensation. We found that the size evolution of icy grains can be divided into two stages. In the first stage, the icy grains grow through condensation of H{sub 2}O molecules. In the second stage, the size of grains changes further as H{sub 2}O molecules are transferred between icy grains while the surrounding gas condenses. The size distribution of the icy dust grains becomes bimodal, with a small number of relatively large grains and many small grains without an icy mantle. Possible effects of the size change on the evolution of icy dust aggregates are discussed.

Kuroiwa, Takuto; Sirono, Sin-iti [Earth and Environmental Sciences, Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8601 (Japan)

2011-09-20T23:59:59.000Z

174

Finite Size Effects on the Real-Space Pair Distribution Function of Nanoparticles  

SciTech Connect

The pair distribution function (PDF) method is a powerful approach for the analysis of the structure of nanoparticles. An important approximation used in nanoparticle PDF simulations is the incorporation of a form factor describing nanoparticle size and shape. The precise effect of the form factor on the PDF is determined by both particle shape and structure if these characteristics are both anisotropic and correlated. The correct incorporation of finite size effects is important for distinguishing and quantifying the structural consequences of small particle size in nanomaterials.

Gilbert, Benjamin

2008-10-01T23:59:59.000Z

175

Analysis of Model-Produced Raindrop Size Distributions in the Small-Drop Range  

Science Conference Proceedings (OSTI)

Current models of drop coalescence and breakup generate raindrop size distributions that evolve toward an equilibrium whose form features a pronounced peak in the small-drop range. It has been known for some time that the peak can be attributed ...

Philip S. Brown Jr.

1999-05-01T23:59:59.000Z

176

Minimizing Instrumental Broadening of the Drop Size Distribution with the M-Fast-FSSP  

Science Conference Proceedings (OSTI)

A modified version of the Fast-FSSP (the so-called M-Fast-FSSP) is introduced. It allows minimization of the instrumental broadening of measured cloud drop size distributions caused by laser beam inhomogeneities. This is achieved by applying a ...

Sebastian Schmidt; Katrin Lehmann; Manfred Wendisch

2004-12-01T23:59:59.000Z

177

The Relationship between N0 and ? for Marshall-Palmer Type Raindrop-Size Distributions  

Science Conference Proceedings (OSTI)

For raindrop-size distributions of the form ND = N0e??D, where ND is the number of drops of diameter D per unit volume per unit increment in drop diameter, the parameters N0 and ? cannot be specified independently as functions of rainfall rate R. ...

J. A. Bennett; D. J. Fang; R. C. Boston

1984-05-01T23:59:59.000Z

178

Interfacial energy effects and the evolution of pore size distributions during quartz precipitation in sandstone  

E-Print Network (OSTI)

Interfacial energy effects and the evolution of pore size distributions during quartz precipitation-scale to nanometer scale pores, interfacial energy (surface energy) effects can also become important. Interfacial energy typically increases the solubility of very small crystals growing in tiny pores, and when

Simon, Emmanuel

179

The Simultaneous Measurement of Rainfall Intensity, Drop-Size Distribution, and the Scattering of Visible Light  

Science Conference Proceedings (OSTI)

Field measurements were made of the attenuation of a low-power. He-Ne laser beam over a 272-m path. Concurrently, high-resolution (10 s) measurements of rainfall intensity were obtained at several points along the path and drop-size distributions ...

C. D. Stow; S. G. Bradley; K. Paulson; L. Couper

1991-10-01T23:59:59.000Z

180

Influence of the Subgrid Variability of the Raindrop Size Distribution on Radar Rainfall Estimators  

Science Conference Proceedings (OSTI)

This work aims at quantifying the variability of the parameters of the power laws used for rain-rate estimation from radar data, on the basis of raindrop size distribution measurements over a typical weather radar pixel. Power laws between the ...

Joël Jaffrain; Alexis Berne

2012-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

An Experimental Study of Small-Scale Variability of Raindrop Size Distribution  

Science Conference Proceedings (OSTI)

An experimental study of small-scale variability of raindrop size distributions (DSDs) has been carried out at Wallops Island, Virginia. Three Joss–Waldvogel disdrometers were operated at a distance of 0.65, 1.05, and 1.70 km in a nearly straight ...

Ali Tokay; Paul G. Bashor

2010-11-01T23:59:59.000Z

182

The Occurrence of Particle Size Distribution Bimodality in Midlatitude Cirrus as Inferred from Ground-Based Remote Sensing Data  

Science Conference Proceedings (OSTI)

Data collected in midlatitude cirrus clouds by instruments on jet aircraft typically show particle size distributions that have distinct distribution modes in both the 10–30-?m maximum dimension (D) size range and the 200–300-?m D size range or ...

Yang Zhao; Gerald G. Mace; Jennifer M. Comstock

2011-06-01T23:59:59.000Z

183

Study of the Physics of Droplet Impingement Cooling  

E-Print Network (OSTI)

Spray cooling is one of the most promising technologies in applications which require large heat removal capacity in very small areas. Previous experimental studies have suggested that one of the main mechanisms of heat removal in spray cooling is forced convection with strong mixing due to droplet impingement. These mechanisms have not been completely understood mainly due to the large number of physical variables, and the inability to modulate and control variables such as droplet frequency and droplet size. Our approach consists of minimizing the number of experimental variables by controlling variables such as droplet direction, velocity and diameter. A study of heat transfer for single and multiple droplet impingements using HFE- 7100 as the cooling fluid under constant heat flux conditions is presented. Monosized single and multiple droplet trains were produced using a piezoelectric droplet generator with the ability to adjust droplet frequency, diameter, velocity, and spacing between adjacent droplets. In this study, heaters consisting of a layer of Indium Tin Oxide (ITO) as heating element, and ZnSe substrates were used. Surface temperature at the liquid-solid interface was measured using Infrared Thermography. Heat transfer behavior was characterized and critical heat flux was measured. Film thickness was measured using a non-invasive optical technique inside the crown formation produced by the impinging droplets. Hydrodynamic phenomena at the droplet impact zone was studied using high speed imaging. Impact regimes of the impinging droplets were identified, and their effect on heat transfer performance were discussed. The results and effects of droplet frequency, droplet diameter, droplet velocity, and fluid flow rate on heat flux behavior, critical heat flux, and film morphology were elucidated. The study showed that forced heat convection is the main heat transfer mechanism inside the crown formation formed by droplet impingement and impact regimes play an important role on heat transfer behavior. In addition, this study found that spacing among adjacent droplets is the most important factor for multiple droplet stream heat transfer behavior. The knowledge generated through the study provides tools and know-how necessary for the design and development of enhanced spray cooling systems.

Soriano, Guillermo Enrique

2011-05-01T23:59:59.000Z

184

The Dependence of Cirrus Cloud-Property Retrievals on Size-Distribution  

NLE Websites -- All DOE Office Websites (Extended Search)

The Dependence of Cirrus Cloud-Property Retrievals on Size-Distribution The Dependence of Cirrus Cloud-Property Retrievals on Size-Distribution Shape d'Entremont, Robert Atmospheric and Environmental Research, Inc. Mitchell, David Desert Research Institute Category: Cloud Properties Our project has focused on using satellite- and ground-based passive thermal infrared radiance observations to retrieve cirrus cloud properties, most importantly ice water path (IWP), effective particle size (Deff), and visible extinction optical thickness (tau). During this past year we began comparing our cirrus retrieval results with aircraft observations at the ARM CART site, and we are participating in a summary intercomparison study with other retrieval algorithms as a member of the high-clouds working group. Our passive-infrared retrieval scheme, based on different wavelength

185

COLOR DEPENDENCE IN THE SIZE DISTRIBUTION OF MAIN BELT ASTEROIDS REVISITED  

SciTech Connect

The size distribution of the asteroid belt is examined with 16956 main belt asteroids detected in data taken from the Canada-France-Hawaii Telescope Legacy Survey in two filters (g' and r'). The cumulative H (absolute magnitude) distribution is examined in both filters, and both match well to simple power laws down to H = 17, with slopes in rough agreement with those reported the literature. This implies that disruptive collisions between asteroids are gravitationally dominated down to at least this size, and probably sub-kilometer scales. The slopes of these distributions appear shallower in the outer belt than the inner belt, and the g' distributions appear slightly steeper than the r'. The slope shallowing in the outer belt may reflect a real compositional difference: the inner asteroid belt has been suggested to consist mostly of stony and/or metallic S-type asteroids, whereas carbonaceous C-types are thought to be more prevalent further from the Sun. No waves are seen in the size distribution above H = 15. Since waves are expected to be produced at the transition from gravitationally-dominated to internal strength-dominated collisions, their absence here may imply that the transition occurs at sub-kilometer scales, much smaller than the H = 17 (diameter {approx} 1.6 km) cutoff of this study.

August, Tyler M.; Wiegert, Paul A., E-mail: tx_august@laurentian.ca [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada)

2013-06-15T23:59:59.000Z

186

Oil droplet in alcohol  

E-Print Network (OSTI)

The elegant patterns formed by fluid droplets falling through a dissimilar liquid were first studied over a century ago.1 The emerging patterns are driven by hydrodynamic instabilities set up by velocity and density gradients ...

La Foy, Roderick R.

187

Universal fluid droplet ejector  

DOE Patents (OSTI)

A droplet generator comprises a fluid reservoir having a side wall made of glass or quartz, and an end cap made from a silicon plate. The end cap contains a micromachined aperture through which the fluid is ejected. The side wall is thermally fused to the end cap, and no adhesive is necessary. This means that the fluid only comes into contact with the side wall and the end cap, both of which are chemically inert. Amplitudes of drive pulses received by reservoir determine the horizontal displacements of droplets relative to the ejection aperture. The drive pulses are varied such that the dropper generates a two-dimensional array of vertically-falling droplets. Vertical and horizontal interdroplet spacings may be varied in real time. Applications include droplet analysis experiments such as Millikan fractional charge searches and aerosol characterization, as well as material deposition applications.

Lee, Eric R. (Redwood City, CA); Perl, Martin L. (Palo Alto, CA)

1999-08-24T23:59:59.000Z

188

Effects of Nanoparticle Geometry and Size Distribution on Diffusion Impedance of Battery Electrodes  

E-Print Network (OSTI)

The short diffusion lengths in insertion battery nanoparticles render the capacitive behavior of bounded diffusion, which is rarely observable with conventional larger particles, now accessible to impedance measurements. Coupled with improved geometrical characterization, this presents an opportunity to measure solid diffusion more accurately than the traditional approach of fitting Warburg circuit elements, by properly taking into account the particle geometry and size distribution. We revisit bounded diffusion impedance models and incorporate them into an overall impedance model for different electrode configurations. The theoretical models are then applied to experimental data of a silicon nanowire electrode to show the effects of including the actual nanowire geometry and radius distribution in interpreting the impedance data. From these results, we show that it is essential to account for the particle shape and size distribution to correctly interpret impedance data for battery electrodes. Conversely, it...

Song, J

2012-01-01T23:59:59.000Z

189

Grain size distributions and photo-electric heating in ionised media  

E-Print Network (OSTI)

Ever since the pioneering study of Spitzer, it has been widely recognised that grains play an important role in the heating and cooling of photo-ionised environments. A detailed code is necessary to model grains in a photo-ionised medium. In this paper we will use the spectral synthesis code Cloudy for this purpose. The grain model of this code has recently undergone a comprehensive upgrade. Part of this is the newly developed hybrid grain charge model, which will be described in detail. This model allows discrete charge states of very small grains to be modelled accurately while simultaneously avoiding the overhead of fully resolving the charge distribution of large grains, thus making the model both accurate and computationally efficient. A comprehensive comparison with the fully resolved charge state models of Weingartner & Draine (2001) shows that the agreement is very satisfactory for realistic size distributions. The effect of the grain size distribution on the line emission from photo-ionised regio...

Van Hoof, P A M; Martin, P G; Volk, K; Ferland, G J

2004-01-01T23:59:59.000Z

190

The Role of Ice Particle Shapes and Size Distributions in the Single Scattering Properties of Cirrus Clouds  

Science Conference Proceedings (OSTI)

The roles of ice particle size distributions (SDs) and particle shapes in cirrus cloud solar radiative transfer are investigated by analyzing SDs obtained from optical array probe measurements (particle sizes larger than 20–40 ?m) during ...

Andreas Macke; Peter N. Francis; Greg M. McFarquhar; Stefan Kinne

1998-09-01T23:59:59.000Z

191

Characteristics of inhalable particulate matter concentration and size distribution from power plants in China  

Science Conference Proceedings (OSTI)

The collection efficiency of particulate emission control devices (PECDs), particulate matter (PM) emissions, and PM size distribution were determined experimentally at the inlet and outlet of PECDs at five coal-fired power plants. Different boilers, coals, and PECDs are used in these power plants. Measurement in situ was performed by an electrical low-pressure impactor with a sampling system, which consisted of an isokinetic sampler probe, precut cyclone, and two- stage dilution system with a sample line to the instruments. The size distribution was measured over a range from 0.03 to 10 {mu}m. Before and after all of the PECDs, the particle number size distributions display a bimodal distribution. The PM2.5 fraction emitted to atmosphere includes a significant amount of the mass from the coarse particle mode. The controlled and uncontrolled emission factors of total PM, inhalable PM (PM10), and fine PM (PM2.5) were obtained. Electrostatic precipitator (ESP) and baghouse total collection efficiencies are 96.38 99.89% and 99.94%, respectively. The minimum collection efficiency of the ESP and the baghouse both appear in the particle size range of 0.1 1 0 {mu}m. In this size range, ESP and baghouse collection efficiencies are 85.79 98.6% and 99.54%. Real- time measurement shows that the mass and number concentration of PM10 will be greatly affected by the operating conditions of the PECDs. The number of emitted particles increases with increasing boiler load level because of higher combustion temperature. During test run periods, the data reproducibility is satisfactory. 19 refs., 11 figs., 6 tabs.

Honghong Yi; Jiming Hao; Lei Duan; Xinghua Li; Xingming Guo [Tsinghua University, Beijing (China). Department of Environmental Science and Engineering

2006-09-15T23:59:59.000Z

192

Scale-free Universal Spectrum for Atmospheric Aerosol Size Distribution for Davos, Mauna Loa and Izana  

E-Print Network (OSTI)

Atmospheric flows exhibit fractal fluctuations and inverse power law form for power spectra indicating an eddy continuum structure for the selfsimilar fluctuations. A general systems theory for fractal fluctuations developed by the author is based on the simple visualisation that large eddies form by space-time integration of enclosed turbulent eddies, a concept analogous to Kinetic Theory of Gases in Classical Statistical Physics. The ordered growth of atmospheric eddy continuum is in dynamical equilibrium and is associated with Maximum Entropy Production. The model predicts universal (scale-free) inverse power law form for fractal fluctuations expressed in terms of the golden mean. Atmospheric particulates are held in suspension in the fractal fluctuations of vertical wind velocity. The mass or radius (size) distribution for homogeneous suspended atmospheric particulates is expressed as a universal scale-independent function of the golden mean, the total number concentration and the mean volume radius. Model predicted spectrum is in agreement (within two standard deviations on either side of the mean) with total averaged radius size spectra for the AERONET (aerosol inversions) stations Davos and Mauna Loa for the year 2010 and Izana for the year 2009 daily averages. The general systems theory model for aerosol size distribution is scale free and is derived directly from atmospheric eddy dynamical concepts. At present empirical models such as the log normal distribution with arbitrary constants for the size distribution of atmospheric suspended particulates are used for quantitative estimation of earth-atmosphere radiation budget related to climate warming/cooling trends. The universal aerosol size spectrum will have applications in computations of radiation balance of earth-atmosphere system in climate models.

A. M. Selvam

2011-11-14T23:59:59.000Z

193

Pore and throat size distributions measured from synchrotron X-ray tomographic images of Fontainebleau sandstones  

E-Print Network (OSTI)

The three-dimensional geometry and connectivity of pore space controls the hydraulic transport behavior of crustal rocks. We report on direct measurement of flow-relevant geometrical properties of the void space in a suite of 4 samples of Fontainebleau sandstone ranging from 7.5% to 22% porosity. The measurements are obtained from computer analysis of three dimensional, synchrotron X-ray computed microtomographic images. We present measured distributions of coordination number, channel length, throat size and pore volume, and of correlations between throat-size/pore-volume and nearest neighbor pore-volume/pore volume determined for these samples. We also present quantitative characterization of the distributions measured. The effects of finite sample volume are investigated. The accuracy of the numerical algorithms employed is investigated using a simulated image of hexagonal closed packed spheres.

W. Brent Lindquist; Arun Venkatarangan; John Dunsmuir; Teng-fong Wong

1999-01-01T23:59:59.000Z

194

Particle size distribution of airborne plutonium near a chemical separations facility  

Science Conference Proceedings (OSTI)

Particulate matter containing Pu-238 and Pu-239,240 emitted from a stack at the Savannah River Plant was collected and fractionated by size with cascade impactors. Two impactor measurements were made at a distance of 200 meters from the H-Area stack and a third was at a distance of 420 meters. Annual collections were made for three years. The Pu-238 and Pu 239,240 concentrations were determined for each of the size fractions. The fractions collected at 200 m from the 62 m stack showed a biphasic curve for both Pu-238 and Pu-239,240. The highest concentration for both Pu-238 and Pu-239,240 were found in the <0.49 ..mu..m fraction, with the secondary peak occurring in the fractions greater than 3.0 ..mu..m. At 420 meters from the stack, the size distribution curves for Pu-238 and Pu-239,240 were not biphasic; only one peak appeared and that was for the fraction less than 0.49 ..mu..m. The doses to different organs from plutonium inhalation were calculated for the particle size distributions obtained in this study. The maximum potential 50-year dose commitment to the bone, the critical organ, for one year continuous exposure was 13 mrem for Pu-238 and 0.44 mrem for Pu-239,240 at 200 meters from the H-Area stack.

Gay, D.D.; Watts, J.R.

1981-12-01T23:59:59.000Z

195

Models for Unsaturated Hydraulic Conductivity Based on Truncated Lognormal Pore-size Distributions  

E-Print Network (OSTI)

We develop a closed-form three-parameter model for unsaturated hydraulic conductivity associated with a three-parameter lognormal model of moisture retention, which is based on lognormal grainsize distribution. The derivation of the model is made possible by a slight modification to the theory of Mualem. We extend the three-parameter lognormal distribution to a four-parameter model that also truncates the pore size distribution at a minimum pore radius. We then develop the corresponding four-parameter model for moisture retention and the associated closed-form expression for unsaturated hydraulic conductivity. The four-parameter model is fitted to experimental data, similar to the models of Kosugi and van Genuchten. The proposed four-parameter model retains the physical basis of Kosugi's model, while improving fit to observed data especially when simultaneously fitting pressure-saturation and pressure-conductivity data.

Malama, Bwalya

2013-01-01T23:59:59.000Z

196

Temporal Variations of Aerosol Optical Parameters Resulting from the Aging of a Model Aerosol Number Size Distribution  

Science Conference Proceedings (OSTI)

Aerosol number size distributions are subject to aging, i.e., to temporal variations. The aging of a Junge number size distribution due to a multitude of processes was modeled by Junge and Abel. The pertinent changes with time of aerosol optical ...

J. Freund

1984-04-01T23:59:59.000Z

197

Condensation and jumping relay of droplets on lotus leaf  

E-Print Network (OSTI)

Dynamic behavior of micro water droplet condensed on a lotus leaf with two-tier roughness is studied. Under laboratory environment, the contact angle of the micro droplet on single micro papilla increases smoothly from 80 deg to 160 deg during the growth of condensed water. The best-known "self-clean" phenomenon, will be lost. A striking observation is the out-of-plane jumping relay of condensed droplets triggered by falling droplets, as well as its sustained speed obtained in continuous jumping relays, enhance the automatic removal of dropwise condensation without the help from any external force. The surface tension energy dissipation is the main reason controlling the critical size of jumping droplet and its onset velocity of rebounding.

Cunjing Lv; Pengfei Hao; Zhaohui Yao; Yu Song; Xiwen Zhang; Feng He

2013-05-09T23:59:59.000Z

198

Spontaneous Charging and Crystallization of Water Droplets in Oil  

E-Print Network (OSTI)

We study the spontaneous charging and the crystallization of spherical micron-sized water-droplets dispersed in oil by numerically solving, within a Poisson-Boltzmann theory in the geometry of a spherical cell, for the density profiles of the cations and anions in the system. We take into account screening, ionic Born self-energy differences between oil and water, and partitioning of ions over the two media. We find that the surface charge density of the droplet as induced by the ion partitioning is significantly affected by the droplet curvature and by the finite density of the droplets. We also find that the salt concentration and the dielectric constant regime in which crystallization of the water droplets is predicted is enhanced substantially compared to results based on the planar oil-water interface, thereby improving quantitative agreement with recent experiments.

Joost de Graaf; Jos Zwanikken; Markus Bier; Arjen Baarsma; Yasha Oloumi; Mischa Spelt; Rene van Roij

2008-07-29T23:59:59.000Z

199

Influence of charging process and size distribution of dust grain on the electric conductivity of dusty plasma  

Science Conference Proceedings (OSTI)

The effects of dust size distribution and charging process of dust grains on the complex electric conductivity of dusty plasmas have been investigated in the present paper. Comparisons are made between real dusty plasma in which there are many different dust grain species and the mono-sized dusty plasma (MDP) in which there is only one kind of dust grain whose size is the average dust size. In some cases the complex electric conductivity of real dusty plasma is larger than that of MDP, while in other cases it is smaller than that of MDP, it depends on the dust size distribution function.

Duan Jizheng; Wang Canglong; Zhang Jianrong; Ma Shengqian; Hong Xueren; Sun Jianan [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Duan Wenshan [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China); Yang Lei [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)

2012-08-15T23:59:59.000Z

200

Continuum representation of a continuous size distribution of particles engaged in rapid granular flow  

Science Conference Proceedings (OSTI)

Natural and industrial granular flows often consist of several particle sizes, approximately forming a continuous particle size distribution (PSD). Continuous PSDs are ubiquitous, though existing kinetic-theory-based, hydrodynamic models for rapid granular flows are limited to a discrete number of species. The objective of this work is twofold: (i) to determine the number of discrete species required to accurately approximate a continuous PSD and (ii) to validate these results via a comparison with molecular dynamics (MD) simulations of continuous PSDs. With regard to the former, several analytic (Gaussian and lognormal) and experimental (coal and lunar soil simulants) distributions are investigated. Transport coefficients (pressure, shear viscosity, etc.) of the granular mixture given by the polydisperse theory of Garz´o et al. [“Enskog theory for polydisperse granular mixtures. I. Navier-Stokes order transport,” Phys. Rev. E 76, 031303 (2007);“Enskog theory for polydisperse granular mixtures. I. Navier-Stokes order transport,” 76, 031304 (2007)] are compared using an increasing number of species s to approximate the given PSD. These discrete approximations are determined by matching the first 2s moments of the approximation and the given continuous distribution. Relatively few species are required to approximate moderately wide distributions (Gaussian, lognormal), whereas even wider distributions (coal and lunar soil simulants) require a larger number of species. Regarding the second objective, a comparison between MD simulations and kinetictheory predictions for a simple shear flow of both Gaussian and lognormal PSDs reveal essentially no loss of accuracy stemming from the polydisperse theory itself (as compared to theories for monodisperse systems) or from the discrete approximations of continuous PSDs used in the polydisperse theory. C #2; 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4744987

Murray, J.A.; Benyahia, S.; Metzger, P.; Hrenya, C.M.

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" from the National Library of EnergyBeta (NLEBeta).
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201

SURFACE AREA, VOLUME, MASS, AND DENSITY DISTRIBUTIONS FOR SIZED BOMASS PARTICLES  

DOE Green Energy (OSTI)

This semi-annual technical progress report describes work performed at Morehouse College under DOE Grant No. DE-FC26-04NT42130 during the period July 01, 2004 to December 31, 2004 which covers the first six months of the project. Presently work is in progress to characterize surface area, volume, mass, and density distributions for sized biomass particles. During this reporting period, supply requests were processed and supplies including biomass test particles (hardwood sawdust AI14546) in the size range of 100-200 microns were obtained from a cofiring pilot plant research facility owned by Southern Company, Birmingham, AL. Morehouse has completed setting up of the gravimetric technique measurement system in the heat transfer laboratory, department of physics and dual degree engineering, Morehouse College. Simultaneously, REM, our subcontractor, has completed setting up of the electrodynamic balance (EDB) measurement system to characterize shape and mass for individual biomass particles. Testing of the gravimetric system, and calibration of the cameras and imaging systems using known sizes of polystyrene particles are in progress.

Ramanathan Sampath

2004-05-01T23:59:59.000Z

202

Hovering UFO Droplets  

E-Print Network (OSTI)

This fluid dynamics video is an entry for the Gallery of Fluid Motion of the 65th Annual Meeting of the APS-DFD. This video shows behavior of condensing droplets on a lubricant impregnated surface and a comparison with a superhydrophobic surface. On impregnated surfaces, drops appear like UFOs hovering over a surface. The videos were recorded in an Environmental SEM and a specially built condensation rig.

Anand, Sushant; Dhiman, Rajeev; Smith, J David; Varanasi, Kripa K

2012-01-01T23:59:59.000Z

203

Structural morphology of acoustically levitated and heated nanosilica droplet  

SciTech Connect

We study the vaporization and precipitation dynamics of a nanosilica encapsulated water droplet by levitating it acoustically and heating it with a CO{sub 2} laser. For all concentrations, we observe three phases: solvent evaporation, surface agglomeration, and precipitation leading to bowl or ring shaped structures. At higher concentrations, ring reorientation and rotation are seen consistently. The surface temperature from an infrared camera is seen to be dependent on the final geometrical shape of the droplet and its rotation induced by the acoustic field of the levitator. With nonuniform particle distribution, these structures can experience rupture which modifies the droplet rotational speed.

Kumar, Ranganathan; Tijerino, Erick; Saha, Abhishek [Department of Mechanical, Materials and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816 (United States); Basu, Saptarshi [Department of Mechanical Engineering, Indian Institute of Science, 560012 Bangalore (India)

2010-09-20T23:59:59.000Z

204

Drop Size Distributions Measured by a 2D Video Disdrometer: Comparison with Dual-Polarization Radar Data  

Science Conference Proceedings (OSTI)

An analysis of drop size distributions (DSDs) measured in four very different precipitation regimes is presented and is compared with polarimetric radar measurements. The DSDs are measured by a 2D video disdrometer, which is designed to measure ...

Terry J. Schuur; Alexander V. Ryzhkov; Dusan S. Zrni?; Michael Schönhuber

2001-06-01T23:59:59.000Z

205

Sea-Salt Size Distributions from Breaking Waves: Implications for Marine Aerosol Production and Optical Extinction Measurements during SEAS  

Science Conference Proceedings (OSTI)

The authors' participation in the Shoreline Environment Aerosol Study (SEAS) involved measurements focused on the coastal aerosol size distribution and related optical measurements, including aerosol light scattering, visibility, and remote ...

A. Clarke; V. Kapustin; S. Howell; K. Moore; B. Lienert; S. Masonis; T. Anderson; D. Covert

2003-10-01T23:59:59.000Z

206

The grain size distribution and the detection of abnormal grain growth of austenite in an eutectoid steel containing niobium  

SciTech Connect

The abnormal grain growth of austenite was studied in a commercial steel of composition (wt%): 0.70 C, 1.36 Mn, 0.72 Si, 0.015 P, 0.027 S and 0.03 Nb. Specimens were thermocycled at various conditions and then grain size distribution determined. The grain size distribution shape did not change during normal grain growth but this distribution widened and flattened during the abnormal grain growth. The initial smaller mean size of carbonitrides and/or the highest homogeneity of niobium carbonitride size distribution of the samples submitted to thermal cycles, in comparison with the normalized samples, increased the abnormal grain growth temperature from 1,373 K to 1,473 K.

Bruno, J.C. (Instituto Militar de Engenharia, Rio de Janeiro (Brazil). Dept. de Engenharia Mecanica e de Materiais); Rios, P.R. (Pontificia Univ. Catolica do Rio de Janeiro (Brazil). Dept. de Ciencia dos Materiais e Metalurgia)

1995-02-15T23:59:59.000Z

207

Measurements of Raindrop Size Distributions over the Pacific Warm Pool and Implications for Z–R Relations  

Science Conference Proceedings (OSTI)

Raindrop images obtained on research flights of the NCAR Electra aircraft in the Tropical Oceans Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE) are analyzed. The drop size distributions, based on the images obtained ...

Sandra E. Yuter; Robert A. Houze Jr.

1997-07-01T23:59:59.000Z

208

Quantification of the Small-Scale Spatial Structure of the Raindrop Size Distribution from a Network of Disdrometers  

Science Conference Proceedings (OSTI)

The spatial structure of the raindrop size distribution (DSD) conveys crucial information for reliable quantitative estimation of rainfall using remote sensing techniques. To investigate this question, a network of 16 optical disdrometers has been ...

Joël Jaffrain; Alexis Berne

2012-05-01T23:59:59.000Z

209

Numerical Investigation of Collision-Induced Breakup of Raindrops. Part II: Parameterizations of Coalescence Efficiencies and Fragment Size Distributions  

Science Conference Proceedings (OSTI)

Results of numerically investigated binary collisions of 32 drop pairs presented in Part I of this study are used to parameterize coalescence efficiencies and size distributions of breakup fragments of large raindrops.

Winfried Straub; Klaus Dieter Beheng; Axel Seifert; Jan Schlottke; Bernhard Weigand

2010-03-01T23:59:59.000Z

210

Observations of Saharan Aerosols: Results of ECLATS Field Experiment. Part I: Optical Thicknesses and Aerosol Size Distributions  

Science Conference Proceedings (OSTI)

A series of ground-based and airborne observations of desert aerosols, the ECLATS experiment was carried out in December 1980 in the vicinity of Niamey (Niger). This paper deals with aerosol optical thicknesses and size distributions derived from ...

Y. Fouquart; B. Bonnel; M. Chaoui Roquai; R. Santer; A. Cerf

1987-01-01T23:59:59.000Z

211

The Modification of Joint Size–Charge Distribution in Rain. Part I: Computations which Exclude Partial Coalescence  

Science Conference Proceedings (OSTI)

The effect of individual charge-modifying processes is tested by following the development joint distributions of raindrop size and charge through a fall depth of 1 km beneath a weakly electrified warm cloud. Evaporation, ion capture and ...

S. G. Bradley; C. D. Stow

1984-10-01T23:59:59.000Z

212

Coincident In Situ and W-Band Radar Measurements of Drop Size Distribution in a Marine Stratus Cloud and Drizzle  

Science Conference Proceedings (OSTI)

Investigation of precipitation formation requires measurements of the drop size distribution in a cloud. These measurements have usually been made using ground-based radar systems or aircraft in situ probes. Difficulties encountered in practice ...

J. Galloway; A. Pazmany; J. Mead; R. E. McIntosh; D. Leon; J. French; S. Haimov; R. Kelly; G. Vali

1999-05-01T23:59:59.000Z

213

Improved Normalization of the Size Distribution of Atmospheric Particles Retrieved from Aureole Measurements Using the Diffraction Approximation  

Science Conference Proceedings (OSTI)

This paper describes an improvement in the diffraction approximation used to retrieve the size distribution of atmospheric particles from solar aureole radiance measurements. Normalization using total optical thickness based on measurement of the ...

J. G. DeVore

2011-08-01T23:59:59.000Z

214

Theoretical analysis for the optical deformation of emulsion droplets  

E-Print Network (OSTI)

We propose a theoretical framework to predict the three-dimensional shapes of optically deformed micron-sized emulsion droplets with ultra-low interfacial tension. The resulting shape and size of the droplet arises out of a balance between the interfacial tension and optical forces. Using an approximation of the laser field as a Gaussian beam, working within the Rayleigh-Gans regime and assuming isotropic surface energy at the oil-water interface, we numerically solve the resulting shape equations to elucidate the three-dimensional droplet geometry. We obtain a plethora of shapes as a function of the number of optical tweezers, their laser powers and positions, surface tension, initial droplet size and geometry. Experimentally, two-dimensional droplet silhouettes have been imaged from above, but their full side-on view has not been observed and reported for current optical configurations. This experimental limitation points to ambiguity in differentiating between droplets having the same two-dimensional projection but with disparate three-dimensional shapes. Our model elucidates and quantifies this difference for the first time. We also provide a dimensionless number that indicates the shape transformation (ellipsoidal to dumbbell) at a value $\\approx 1.0$, obtained by balancing interfacial tension and laser forces, substantiated using a data collapse.

David Tapp; Jonathan M. Taylor; Alex S. Lubanksy; Colin D. Bain; Buddhapriya Chakrabarti

2013-08-13T23:59:59.000Z

215

SURFACE AREA, VOLUME, MASS, AND DENSITY DISTRIBUTIONS FOR SIZED BIOMASS PARTICLES  

DOE Green Energy (OSTI)

This semi-annual technical progress report describes work performed at Morehouse College under DOE Grant No. DE-FC26-04NT42130 during the period July 01, 2005 to December 31, 2005 which covers the third six months of the project. Presently work is in progress to characterize surface area, volume, mass, and density distributions for sized biomass particles. During this reporting period, Morehouse continued to obtain additional mean mass measurements for biomass particles employing the gravimetric technique measurement system that was set up in the last reporting period. Simultaneously, REM, our subcontractor, has obtained raw data for surface area, volume, and drag coefficient to mass ratio (C{sub d}/m) information for several biomass particles employing the electrodynamic balance (EDB) measurement system that was calibrated in the last reporting period. Preliminary results of the mean mass and the shape data obtained are reported here, and more data collection is in progress.

Ramanathan Sampath

2006-01-01T23:59:59.000Z

216

SURFACE AREA, VOLUME, MASS, AND DENSITY DISTRIBUTIONS FOR SIZED BIOMASS PARTICLES  

DOE Green Energy (OSTI)

This semi-annual technical progress report describes work performed at Morehouse College under DOE Grant No. DE-FC26-04NT42130 during the period January 01, 2006 to June 30, 2006 which covers the fourth six months of the project. Presently work is in progress to characterize surface area, volume, mass, and density distributions for sized biomass particles. During this reporting period, Morehouse completed obtaining additional mean mass measurements for biomass particles employing the gravimetric technique measurement system that was set up in a previous reporting period. Simultaneously, REM, our subcontractor, has completed obtaining raw data for surface area, volume, and drag coefficient to mass ratio (Cd/m) information for 9 more biomass particles employing the electrodynamic balance (EDB) measurement system that was calibrated before in this project. Results of the mean mass data obtained to date are reported here, and analysis of the raw data collected by REM is in progress.

Ramanathan Sampath

2006-06-30T23:59:59.000Z

217

The sizes and powers of some stochastic dominance tests: A Monte Carlo study for correlated and heteroskedastic distributions  

Science Conference Proceedings (OSTI)

Testing for stochastic dominance among distributions is an important issue in the study of asset management, income inequality, and market efficiency. This paper conducts Monte Carlo simulations to examine the sizes and powers of several commonly used ... Keywords: C12, Correlated distributions, D31, G11, Grid points, Heteroskedasticity, Stochastic dominance

Hooi-Hooi Lean; Wing-Keung Wong; Xibin Zhang

2008-10-01T23:59:59.000Z

218

A General Systems Theory for Atmospheric Flows and Atmospheric Aerosol Size Distribution  

E-Print Network (OSTI)

Atmospheric flows exhibit selfsimilar fractal spacetime fluctuations manifested as the fractal geometry to global cloud cover pattern and inverse power law form for power spectra of meteorological parameters such as windspeed, temperature, rainfall etc. Inverse power law form for power spectra indicate long-range spacetime correlations or non-local connections and is a signature of selforganised criticality generic to dynamical systems in nature such as river flows, population dynamics, heart beat patterns etc. The author has developed a general systems theory which predicts the observed selforganised criticality as a signature of quantumlike chaos in dynamical systems. The model predictions are (i) The fractal fluctuations can be resolved into an overall logarithmic spiral trajectory with the quasiperiodic Penrose tiling pattern for the internal structure. (ii) The probability distribution represents the power (variance) spectrum for fractal fluctuations and follows universal inverse power law form incorporating the golden mean. Such a result that the additive amplitudes of eddies when squared represent probability distribution is observed in the subatomic dynamics of quantum systems such as the electron or photon. Therefore the irregular or unpredictable fractal fluctuations exhibit quantumlike chaos. (iii) Atmospheric aerosols are held in suspension by the vertical velocity distribution (spectrum). The atmospheric aerosol size spectrum is derived in terms of the universal inverse power law characterizing atmospheric eddy energy spectrum. Model predicted spectrum is in agreement with the following two experimentally determined atmospheric aerosol data sets, (i) SAFARI 2000 CV-580 Aerosol Data, Dry Season 2000 (CARG) (ii) World Data Centre Aerosols data sets for the three stations Ny {\\AA}lesund, Pallas and Hohenpeissenberg.

A. M. Selvam

2009-08-17T23:59:59.000Z

219

Investigation of Droplet Size Distributions and Drizzle Formation Using a New Trajectory Ensemble Model. Part I: Model Description and First Results in a Nonmixing Limit  

Science Conference Proceedings (OSTI)

A novel trajectory ensemble model of a stratocumulus cloud is described. In this model, the boundary layer (BL) is fully covered by a great number of Lagrangian air parcels that during their motion can contain either wet aerosols or aerosols and ...

M. Pinsky; L. Magaritz; A. Khain; O. Krasnov; A. Sterkin

2008-07-01T23:59:59.000Z

220

The representation of rainfall drop-size distribution and kinetic energy Hydrology and Earth System Sciences, 8(5), 10011007 (2004) EGU  

E-Print Network (OSTI)

The representation of rainfall drop-size distribution and kinetic energy 1001 Hydrology and Earth-size distribution and kinetic energy Neil I. Fox Department of Soil, Environmental and Atmospheric Sciences373 Mc component of drop velocity. Keywords: drop-size distribution, drop kinetic energy, soil erosion Introduction

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "droplet size distribution" 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

Coalescence of Pickering emulsion droplets induced by an electric field  

E-Print Network (OSTI)

Combining high-speed photography with electric current measurement, we investigate the electrocoalescence of Pickering emulsion droplets. Under high enough electric field, the originally-stable droplets coalesce via two distinct approaches: normal coalescence and abnormal coalescence. In the normal coalescence, a liquid bridge grows continuously and merges two droplets together, similar to the classical picture. In the abnormal coalescence, however, the bridge fails to grow indefinitely; instead it breaks up spontaneously due to the geometric constraint from particle shells. Such connecting-then-breaking cycles repeat multiple times, until a stable connection is established. In depth analysis indicates that the defect size in particle shells determines the exact merging behaviors: when the defect size is larger than a critical size around the particle diameter, normal coalescence will show up; while abnormal coalescence will appear for coatings with smaller defects.

Guo Chen; Peng Tan; Shuyu Chen; Jiping Huang; Weijia Wen; Lei Xu

2013-02-26T23:59:59.000Z

222

Estimating Maximum Droplet Size that can Evaporate to a Respirable Size Droplet  

SciTech Connect

The Hanford K Basin Closure Project involves the retrieval, transfer and processing of slurries and solutions containing partially corroded spent nuclear fuel from the K Basin spent fuel pools and dissolved contaminants such as cesium. The spent fuel is primarily metallic fuel from the operation of the Hanford reactors. The Sludge Treatment Project (STP) is being designed to treat and package this material in preparation for ultimate disposal.

Schmitt, Bruce E.; Mahoney, Lenna A.; Ryan, Grant W.

2007-04-26T23:59:59.000Z

223

Surface Area, Volume, Mass, and Density Distributions for Sized Biomass Particles  

DOE Green Energy (OSTI)

This final technical report describes work performed at Morehouse College under DOE Grant No. DE-FC26-04NT42130 during the period July 01, 2004 to June 30, 2007 which covers the entire performance period of the project. 25 individual biomass particles (hardwood sawdust AI14546 in the size range of 100-200 microns) were levitated in an electrodynamic balance (EDB) and their external surface area, volume, and drag coefficient/mass (C{sub d}/m) ratios were characterized applying highly specialized video based and high-speed diode array imaging systems. Analysis methods were employed using shape and drag information to calculate mass and density distributions for these particles. Results of these measurements and analyses were validated by independent mass measurements using a particle weighing and counting technique. Similar information for 28 PSOC 1451D bituminous coal particles was retrieved from a previously published work. Using these two information, density correlations for coal/biomass blends were developed. These correlations can be used to estimate the density of the blend knowing either the volume fraction or the mass fraction of coal in the blend. The density correlations presented here will be useful in predicting the burning rate of coal/biomass blends in cofiring combustors. Finally, a discussion on technological impacts and economic projections of burning biomass with coal in US power plants is presented.

Ramanathan Sampath

2007-06-30T23:59:59.000Z

224

Impacts of Venturi Turbulent Mixing on the Size Distributions of Sodium Chloride and Dioctyl-Phthalate Aerosols  

DOE Green Energy (OSTI)

Internal combustion engines are a major source of airborne particulate matter (PM). The size of the engine PM is in the sub-micrometer range. The number of engine particles per unit volume is high, normally in the range of 10{sup 12} to 10{sup 14}. To measure the size distribution of the engine particles dilution of an aerosol sample is required. A diluter utilizing a venturi ejector mixing technique is commercially available and tested. The purpose of this investigation was to determine if turbulence created by the ejector in the mini-dilutor changes the size of particles passing through it. The results of the NaCl aerosol experiments show no discernible difference in the geometric mean diameter and geometric standard deviation of particles passing through the ejector. Similar results were found for the DOP particles. The ratio of the total number concentrations before and after the ejector indicates that a dilution ratio of approximately 20 applies equally for DOP and NaCl particles. This indicates the dilution capability of the ejector is not affected by the particle composition. The statistical analysis results of the first and second moments of a distribution indicate that the ejector may not change the major parameters (e.g., the geometric mean diameter and geometric standard deviation) characterizing the size distributions of NaCl and DOP particles. However, when the skewness was examined, it indicates that the ejector modifies the particle size distribution significantly. The ejector could change the skewness of the distribution in an unpredictable and inconsistent manner. Furthermore, when the variability of particle counts in individual size ranges as a result of the ejector is examined, one finds that the variability is greater for DOP particles in the size range of 40-150 nm than for NaCl particles in the size range of 30 to 350 nm. The numbers or particle counts in this size region are high enough that the Poisson counting errors are small (<10%) compared with the tail regions. This result shows that the ejector device could have a higher bin-to-bin counting uncertainty for ''soft'' particles such as DOP than for a solid dry particle like NaCl. The results suggest that it may be difficult to precisely characterize the size distribution of particles ejected from the mini-dilution system if the particle is not solid.

Cheng, M-D.

2000-08-23T23:59:59.000Z

225

Doppler Cloud Radar Derived Drop Size Distributions in Liquid Water Stratus Clouds  

Science Conference Proceedings (OSTI)

A cloud particle size retrieval algorithm that uses radar reflectivity factor and Doppler velocity obtained by a 35-GHz Doppler radar and liquid water path estimated from microwave radiometer radiance measurements is developed to infer the size ...

Seiji Kato; Gerald G. Mace; Eugene E. Clothiaux; James C. Liljegren; Richard T. Austin

2001-10-01T23:59:59.000Z

226

Compact cryogenic source of periodic hydrogen and argon droplet beams for relativistic laser-plasma generation  

Science Conference Proceedings (OSTI)

We present a cryogenic source of periodic streams of micrometer-sized hydrogen and argon droplets as ideal mass-limited target systems for fundamental intense laser-driven plasma applications. The highly compact design combined with a high temporal and spatial droplet stability makes our injector ideally suited for experiments using state-of-the-art high-power lasers in which a precise synchronization between the laser pulses and the droplets is mandatory. We show this by irradiating argon droplets with multi-terawatt pulses.

Fraga, R. A. Costa; Kalinin, A.; Kuehnel, M.; Schottelius, A. [Institut fuer Kernphysik, J. W. Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Hochhaus, D. C.; Neumayer, P. [EMMI Extreme Matter Institute and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); FIAS Frankfurt Institute for Advanced Studies, J. W. Goethe-Universitaet, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Polz, J. [Institut fuer Optik und Quantenelektronik, Max-Wien-Platz 1, 07743 Jena (Germany); Kaluza, M. C. [Institut fuer Optik und Quantenelektronik, Max-Wien-Platz 1, 07743 Jena (Germany); Helmholtz-Institut Jena, Froebelstieg 3, 07743 Jena (Germany); Grisenti, R. E. [Institut fuer Kernphysik, J. W. Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany)

2012-02-15T23:59:59.000Z

227

Impacts of Venturi Turbulent Mixing on the Size Distribution of Sodium Chloride and Dioctyl-Phthalate Aerosols  

DOE Green Energy (OSTI)

Internal combustion engines are a major source of airborne particulate matter (PM). The size of the engine PM is in the sub-micrometer range. The number of engine particles per unit volume is high, normally in the range of 10{sup 12} to 10{sup 14}. To measure the size distribution of the engine particles dilution of an aerosol sample is required. A diluter utilizing a venturi ejector mixing technique is commercially available and tested. The purpose of this investigation was to determine if turbulence created by the ejector in the mini-dilutor changes the size of particles passing through it.

Cheng, M.-D.; Wainman, T.; Storey, J.

2000-08-01T23:59:59.000Z

228

Statistics and Parameterizations of the Effect of Turbulence on the Geometric Collision Kernel of Cloud Droplets  

Science Conference Proceedings (OSTI)

Collision statistics of cloud droplets in turbulent flow have been calculated for 12 droplet size combinations in four flow fields with levels of the eddy dissipation rate of turbulent kinetic energy ranging from 95 to 1535 cm2 s?3. The flow ...

Charmaine N. Franklin; Paul A. Vaillancourt; M. K. Yau

2007-03-01T23:59:59.000Z

229

Residual carbon from pulverized coal fired boilers 1: Size distribution and combustion reactivity  

Science Conference Proceedings (OSTI)

The amount of residual, or unburned, carbon in fly ash is an important concern in the design and operation of pulverized coal-fired boilers. Char oxidation is the slowest step in the coal combustion process, and the rate at which this heterogeneous reaction-proceeds has an important effect on the degree of carbon burnout. There is an extensive literature on char combustion kinetics based on data in the early and intermediate stages of carbon conversion. A critical fundamental question is whether the small fraction of the fuel carbon that passes unreacted through a boiler is representative of the char during the main portion of the combustion process. This article addresses that question through a detailed characterization of eight carbon-containing fly ash samples acquired from commercial-scale combustion systems. The fly ash characterization included measurement-of joint carbon/size distribution and determination.of the combustion reactivity of the residual carbon. To minimize mineral matter interactions in the reactivity tests, the technique of incipient fluidization was developed for separation of carbon-rich extracts from the inorganic portion of the fly ash. Reactivity measurements were made at 1400--1800 K to represent conditions in pulverized coal fired boilers. Measurements were also made at 700--1100 K to. minimize transport effects and isolate the influence of char chemistry and microstructure. In both temperature regimes, the residual carbon extracts. were significantly less reactive than chars extracted from a laboratory-scale laminar flow reactor in the early-to-intermediate stages of combustion. It is concluded that the boiler environment deactivates chars, making high carbon burnout more difficult to achieve than is predicted by existing char combustion kinetic models that were developed from data on the laboratory chars. Finally, the results are used to discuss potential char deactivation mechanisms, both thermal and oxidative, in coal-fired boilers.

Hurt, R.H. [Sandia National Labs., Livermore, CA (United States); Gibbins, J.R. [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Mechanical Engineering

1994-08-01T23:59:59.000Z

230

Droplet Combustion and Non-Reactive Shear-Coaxial Jets with Transverse Acoustic Excitation  

E-Print Network (OSTI)

Related Works in Droplet Combustion . . . . . . . .of Acoustics on Droplet Combustion . . . . . . . . . . . .Fuel Droplet Combustion . . . . . . . . . . . . . . .

Teshome, Sophonias

2012-01-01T23:59:59.000Z

231

The Relation between the Area-Average Rain Rate and the Rain Cell Size Distribution Parameters  

Science Conference Proceedings (OSTI)

A review of the literature on the rain cell diameter distribution (RCDD) is first presented. It shows that RCDD, for a given rain-rate threshold ?, is accurately described by an exponential distribution with an exponential parameter ? weakly ...

Henri Sauvageot; Frédéric Mesnard; Ricardo S. Tenório

1999-01-01T23:59:59.000Z

232

Aerosol Particle Size Distribution (0.1–1.0 ?m) during the Chinooks of 1979 over Calgary, Canada  

Science Conference Proceedings (OSTI)

During the winter months of 1979, an Active Scattering Aerosol Spectrometer was operated in down-town Calgary to measure the effect of chinooks on the aerosol particle size distribution in the range 0.1–1.0 ?m. An Aerovironment Acoustic Sounder ...

C. V. Mathai; A. W. Harrison; T. Mathews

1980-05-01T23:59:59.000Z

233

Ultrafine particles formed by heating droplets of simulated ash containing metals  

Science Conference Proceedings (OSTI)

Coal and biomass combustion and waste incineration produce inorganic aerosol, whose ultrafine fraction is hypothesized to be generated mainly by metal vaporization and subsequent nucleation and growth in a high-temperature atmosphere. To investigate this mechanism, we investigated nanoparticle inception and early growth processes at high temperature by spraying monodisperse droplets of simulated ash containing metals in the centerline of a laboratory ethylene/air laminar premixed flame at stoichiometric conditions. Particles were collected by thermophoresis on mica substrates for atomic force microscopy dimensional and morphological analysis. Chemical nature, volume fraction, and mean diameter of particles were evaluated by in situ UV-Vis broadband light absorption and laser light-scattering measurements. We also measured size distribution of material sampled from the flame without dilution using differential mobility analysis and scanning electron microscopy. Energy dispersive X-ray spectroscopy provided further information on the chemical composition of particles deposited on substrates. Size distributions showed that the flame-generated aerosol have a high number concentration, are mostly smaller than 10 nm, and persist far downstream of the droplet injection point. Preliminary results showed that the coagulation rate of those nanoparticles is much slower than their collision rate, which implies that their lifetime may be long and may represent a severe problem for environmental pollution.

Carbone, F.; Barone, A.; Pagliara, R.; Beretta, F.; D'Anna, A.; D'Alessio, A. [University of Naples Federico II, Naples (Italy)

2008-12-15T23:59:59.000Z

234

Sieveless particle size distribution analysis of particulate materials through computer vision  

DOE Green Energy (OSTI)

This paper explores the inconsistency of length-based separation by mechanical sieving of particulate materials with standard sieves, which is the standard method of particle size distribution (PSD) analysis. We observed inconsistencies of length-based separation of particles using standard sieves with manual measurements, which showed deviations of 17 22 times. In addition, we have demonstrated the falling through effect of particles cannot be avoided irrespective of the wall thickness of the sieve. We proposed and utilized a computer vision with image processing as an alternative approach; wherein a user-coded Java ImageJ plugin was developed to evaluate PSD based on length of particles. A regular flatbed scanner acquired digital images of particulate material. The plugin determines particles lengths from Feret's diameter and width from pixel-march method, or minor axis, or the minimum dimension of bounding rectangle utilizing the digital images after assessing the particles area and shape (convex or nonconvex). The plugin also included the determination of several significant dimensions and PSD parameters. Test samples utilized were ground biomass obtained from the first thinning and mature stand of southern pine forest residues, oak hard wood, switchgrass, elephant grass, giant miscanthus, wheat straw, as well as Basmati rice. A sieveless PSD analysis method utilized the true separation of all particles into groups based on their distinct length (419 639 particles based on samples studied), with each group truly represented by their exact length. This approach ensured length-based separation without the inconsistencies observed with mechanical sieving. Image based sieve simulation (developed separately) indicated a significant effect (P < 0.05) on number of sieves used in PSD analysis, especially with non-uniform material such as ground biomass, and more than 50 equally spaced sieves were required to match the sieveless all distinct particles PSD analysis. Results substantiate that mechanical sieving, owing to handling limitations and inconsistent length-based separation of particles, is inadequate in determining the PSD of non-uniform particulate samples. The developed computer vision sieveless PSD analysis approach has the potential to replace the standard mechanical sieving. The plugin can be readily extended to model (e.g., Rosin Rammler) the PSD of materials, and mass-based analysis, while providing several advantages such as accuracy, speed, low cost, automated analysis, and reproducible results.

Igathinathane, C. [Mississippi State University (MSU); Pordesimo, L. O. [Mississippi State University (MSU); Columbus, Eugene P [ORNL; Batchelor, William D [ORNL; Sokhansanj, Shahabaddine [ORNL

2009-05-01T23:59:59.000Z

235

A Three Parameter Representation of the Shape and Size Distributions of Hailstones—A Case Study  

Science Conference Proceedings (OSTI)

The characteristics of shapes and sizes of a sample of 679 hailstones, collected on 22 June 1976 during a hailstorm at Grover, Colorado, were analyzed using a three-parameter formula developed by us previously. These parameters are a, the ...

Pao K. Wang; Thomas J. Greenwald; Jianlu Wang

1987-04-01T23:59:59.000Z

236

Impact of Precipitation on Aerosol Spectral Optical Depth and Retrieved Size Distributions: A Case Study  

Science Conference Proceedings (OSTI)

A case study is presented on the impact of two isolated, strong thundershowers during a prevailing dry, sunny season on the spectral optical depths and inferred columnar size characteristics of atmospheric aerosols at a tropical station. Results ...

Auromeet Saha; K. Krishna Moorthy

2004-06-01T23:59:59.000Z

237

A Study of Cirrus Ice Particle Size Distribution Using TC4 Observations  

Science Conference Proceedings (OSTI)

An analysis of two days of in situ observations of ice particle size spectra, in convectively generated cirrus, obtained during NASA’s Tropical Composition, Cloud, and Climate Coupling (TC4) mission is presented. The observed spectra are examined ...

Lin Tian; Gerald M. Heymsfield; Lihua Li; Andrew J. Heymsfield; Aaron Bansemer; Cynthia H. Twohy; Ramesh C. Srivastava

2010-01-01T23:59:59.000Z

238

Optimal Placement and Sizing of Distributed Generator Units using Genetic Optimization  

E-Print Network (OSTI)

and electricity in the distribution grid. A group of DG units can form a virtual power plant, being centrally of distributed generation units in a residential distri- bution grid. Power losses are minimized while grid topology with pro- duction and residential load data based on measurements. Different scenarios

239

Method and apparatus for controlled size distribution of gel microspheres formed from aqueous dispersions  

DOE Patents (OSTI)

The present invention is directed to a method and apparatus for making a population of dense, closely size-controlled microspheres by sol-gel procedures wherein said microspheres are characterized by a significant percentage of said population being within a predetermined, relatively narrow size range. Microsphere populations thus provided are useful in vibratory-packed processes for nuclear fuels to be irradiated in LWR- and FBR-type nuclear reactors.

Ryon, Allen D. (Oak Ridge, TN); Haas, Paul A. (Knoxville, TN); Vavruska, John S. (Santa Fe, NM)

1984-01-01T23:59:59.000Z

240

Growth of Aqueous Solution Droplets of HNO3 and HCl in the Atmosphere  

Science Conference Proceedings (OSTI)

Computed values of equilibrium sizes and composition of uncharged and charged aqueous solution droplets of HNO3 and HCl at 25°C, relative humidifies from 5 to 101%, and solute vapor activities from 10? to 107 are presented. Threshold ...

P. V. N. Nair; P. V. Joshi; U. C. Mishra; K. G. Vohra

1983-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Ice nucleation and droplet formation by bare and coated soot particles  

E-Print Network (OSTI)

We have studied ice formation at temperatures relevant to homogeneous and heterogeneous ice nucleation, as well as droplet activation and hygroscopicity, of soot particles of variable size and composition. Coatings of ...

Friedman, Beth

242

KNIFE MILL COMMINUTION ENERGY ANALYSIS OF SWITCHGRASS, WHEAT STRAW, AND CORN STOVER AND CHARACTERIZATION OF PARTICLE SIZE DISTRIBUTIONS  

Science Conference Proceedings (OSTI)

Biomass preprocessing and pretreatment technologies such as size reduction and chemical preconditioning are aimed at reducing the cost of ethanol production from lignocellulosic biomass. Size reduction is an energy-intensive biomass preprocessing unit operation. In this study, switchgrass, wheat straw, and corn stover were chopped in an instrumented knife mill to evaluate size reduction energy and corresponding particle size distribution as determined with a standard forage sieve analyzer. Direct mechanical power inputs were determined using a dedicated data acquisition system for knife mill screen openings from 12.7 to 50.8 mm, rotor speeds between 250 and 500 rpm, and mass feed rates from 1 to 11 kg/min. A speed of 250 rpm gave optimum performance of the mill. Optimum feed rates for 25.4 mm screen and 250 rpm were 7.6, 5.8, and 4.5 kg/min for switchgrass, wheat straw, and corn stover, respectively. Total specific energy (MJ/Mg) was defined as the size reduction energy required to operate the knife mill plus that imparted to the biomass. Effective specific energy was defined as the energy imparted to the biomass. For these conditions, total specific energies were 27.3, 37.9, and 31.9 MJ/Mg and effective specific energies were 10.1, 15.5, and 3.2 MJ/Mg for switchgrass, wheat straw, and corn stover, respectively. These results demonstrated that biomass selection affects the size reduction energy, even for biomass with similar features. Second-order polynomial equations for the total specific energy requirement fitted well (R2 > 0.95) as a function of knife mill screen size, mass feed rate, and speed for biomass materials tested. The Rosin-Rammler equation fitted the cumulative undersize mass of switchgrass, wheat straw, and corn stover chop passed through ASABE sieves with high R2 (>0.983). Knife mill chopping of switchgrass, wheat straw, and corn stover resulted in particle size distributions classified as 'well-graded strongly fine-skewed mesokurtic', 'well-graded fine-skewed mesokurtic', and 'well-graded fine-skewed mesokurtic', respectively, for small knife mill screen sizes (12.7 to 25.4 mm) and distributions classified as 'well-graded fine-skewed mesokurtic', 'well-graded strongly fine-skewed mesokurtic', and 'well-graded fine-skewed mesokurtic', respectively, for the large screen size (50.8 mm). Total and effective specific energy values per unit size reduction of wheat straw were greater compared to those for switchgrass. Corn stover resulted in reduced total and effective specific energy per unit size reduction compared to wheat straw for the same operating conditions, but higher total specific energy per unit size reduction and lesser effective specific energy per unit size reduction compared to switchgrass. Data on minimized total specific energy with corresponding particle spectra will be useful for preparing feed material with a knife mill for subsequent grinding with finer size reduction devices.

Bitra, V.S.P. [University of Tennessee, Knoxville (UTK); Womac, A.R. [University of Tennessee, Knoxville (UTK); Sokhansanj, Shahabaddine [ORNL; Igathinathane, C. [North Dakota State University

2010-01-01T23:59:59.000Z

243

Refractive Index and Size Distribution of Aerosols as Estimated from Light Scattering Measurements  

Science Conference Proceedings (OSTI)

Angular distributions of the intensity of light scattered by airborne particles were measured for both parallel and perpendicularly polarized components. A precision polar nephelometer was constructed for use of this study. The data were analyzed ...

Masayuki Tanaka; Tamio Takamura; Teruyuki Nakajima

1983-07-01T23:59:59.000Z

244

Marine particle dynamics : sinking velocities, size distributions, fluxes, and microbial degradation rates  

E-Print Network (OSTI)

The sinking flux of particulate matter into the ocean interior is an oceanographic phenomenon that fuels much of the metabolic demand of the subsurface ocean and affects the distribution of carbon and other elements ...

McDonnell, Andrew M. P

2011-01-01T23:59:59.000Z

245

Method and apparatus for controlled size distribution of gel microspheres formed from aqueous dispersions. [Patent application  

DOE Patents (OSTI)

The present invention is directed to a method and apparatus for making a population of dense, closely size-controlled microspheres by sol-gel procedures wherein said microspheres are characterized by a significant percentage of said population being within a predetermined, relatively narrow size range. This is accomplished by subjecting aqueous dispersions of a sol, within a water-immiscible organic liquid to a turbulent flow. Microsphere populations thus provided are useful in vibratory-packed processes for nuclear fuels to be irradiated in LWR- and FBR-type nuclear reactors.

Ryon, A.D.; Haas, P.A.; Vavruska, J.S.

1982-01-19T23:59:59.000Z

246

Quantitative size-dependent structure and strain determination of CdSe nanoparticles using atomic pair distribution function analysis  

E-Print Network (OSTI)

The size-dependent structure of CdSe nanoparticles, with diameters ranging from 2 to 4 nm, has been studied using the atomic pair distribution function (PDF) method. The core structure of the measured CdSe nanoparticles can be described in terms of the wurtzite atomic structure with extensive stacking faults. The density of faults in the nanoparticles ~50% . The diameter of the core region was extracted directly from the PDF data and is in good agreement with the diameter obtained from standard characterization methods suggesting that there is little surface amorphous region. A compressive strain was measured in the Cd-Se bond length that increases with decreasing particle size being 0.5% with respect to bulk CdSe for the 2 nm diameter particles. This study demonstrates the size-dependent quantitative structural information that can be obtained even from very small nanoparticles using the PDF approach.

A. S. Masadeh; E. Bozin; C. L. Farrow; G. Paglia; P. Juhas; A. Karkamkar; M. G. Kanatzidis; S. J. L. Billinge

2007-04-10T23:59:59.000Z

247

Contact Versus Immersion Freezing of Freely Suspended Droplets by Bacterial Ice Nuclei  

Science Conference Proceedings (OSTI)

Droplets freely suspended in the air stream of a wind tunnel were nucleated with dedicated bacterial cells in either the contact or immersion mode. Immersion freezing seemed to give a noncontinuous frequency distribution of freezing with ...

Zev Levin; Saul A. Yankofsky

1983-11-01T23:59:59.000Z

248

Quantitative discrimination between geological materials with variable density contrast by high resolution X-ray computed tomography: An example using amygdule size-distribution in ancient lava flows  

Science Conference Proceedings (OSTI)

The bubble-size distribution in 2.7 billion year old lava flows can be used as a proof of concept illustrating a new set of techniques for measuring volumes of geological materials with variable density contrasts using high-resolution X-ray computed ... Keywords: Amygdules, Bootstrap resampling, Bubble-size distribution, Central limit theorem, Dynamic thresholding, X-ray tomography

Sanjoy M. Som, James W. Hagadorn, Weston A. Thelen, Alan R. Gillespie, David C. Catling, Roger Buick

2013-04-01T23:59:59.000Z

249

An Inversion Problem on Inferring the Size Distribution of Precipitation Areas from Raingage Measurements  

Science Conference Proceedings (OSTI)

Given a long, continuous record of rain rate measured at a point on the ground, it is straightforward to select a threshold value of rate and note the duration of each event in which the threshold is exceeded. The distribution of durations for ...

M. K. Yau; R. R. Rogers

1984-02-01T23:59:59.000Z

250

The Visualization of Cloud Droplet Spectra  

Science Conference Proceedings (OSTI)

This paper draws attention to the use of readily available, wire cage graphics for inspecting cloud droplet spectra measured using a Forward Light-Scattering Spectrometer Probe. The high resolution cloud droplet spectra from two different clouds ...

Robert R. Czys

1989-02-01T23:59:59.000Z

251

The Temperature of Evaporating Sea Spray Droplets  

Science Conference Proceedings (OSTI)

Evaporating sea spray droplets are often assumed to be at the temperature of a well-ventilated wet-bulb thermometer, Twet. Although this assumption may be accurate enough in practice, it is incorrect on theoretical grounds. Spray droplets have ...

Edgar L. Andreas

1995-04-01T23:59:59.000Z

252

FSSP Characterization with Monodisperse Water Droplets  

Science Conference Proceedings (OSTI)

A droplet generator was used to calibrate and study some features of the forward-scattering spectrometer probe (FSSP). The generator produces a stable jet of monodisperse droplets with the rate of 50–500 droplets per second and a velocity between ...

M. Wendisch; A. Keil; A. V. Korolev

1996-12-01T23:59:59.000Z

253

In-situ droplet monitoring for self-tuning spectrometers  

DOE Patents (OSTI)

A laser scattering based imaging technique is utilized in order to visualize the aerosol droplets in an inductively coupled plasma (ICP) torch from an aerosol source to the site of analytical measurements. The resulting snapshots provide key information about the spatial distribution of the aerosol introduced by direct and indirect injection devices: 1) a direct injection high efficiency nebulizer (DIHEN); 2) a large-bore DIHEN (LB-DIHEN); and 3) a PFA microflow nebulizer with a PFA Scott-type spray chamber. Moreover, particle image velocimetry (PIV) is used to study the in-situ behavior of the aerosol before interaction with, for example, plasma, while the individual surviving droplets are explored by particle tracking velocimetry (PTV). Further, the velocity distribution of the surviving droplets demonstrates the importance of the initial droplet velocities in complete desolvation of the aerosol for optimum analytical performance in ICP spectrometries. These new observations are important in the design of the next-generation direct injection devices for lower sample consumption, higher sensitivity, lower noise levels, suppressed matrix effects, and for developing smart spectrometers. For example, a controller can be provided to control the output of the aerosol source by controlling the configuration of the source or the gas flow rate via feedback information concerning the aerosol.

Montaser, Akbar (Potomac, MD); Jorabchi, Kaveh (Arlington, VA); Kahen, Kaveh (Kleinburg, CA)

2010-09-28T23:59:59.000Z

254

Drop Size Separation in Numerically Simulated Convective Clouds and Its Effect on Warm Rain Formation  

Science Conference Proceedings (OSTI)

It is shown that, as a result of the flow diffluence at the upper levels of the cloud, droplets of different sizes move along different trajectories. The small droplets with negligible fall velocities will have higher probability of being carried ...

Yefim L. Kogan

1993-05-01T23:59:59.000Z

255

Critical error rate of quantum-key-distribution protocols versus the size and dimensionality of the quantum alphabet  

SciTech Connect

A quantum-information analysis of how the size and dimensionality of the quantum alphabet affect the critical error rate of the quantum-key-distribution (QKD) protocols is given on an example of two QKD protocols--the six-state and {infinity}-state (i.e., a protocol with continuous alphabet) ones. In the case of a two-dimensional Hilbert space, it is shown that, under certain assumptions, increasing the number of letters in the quantum alphabet up to infinity slightly increases the critical error rate. Increasing additionally the dimensionality of the Hilbert space leads to a further increase in the critical error rate.

Sych, Denis V.; Grishanin, Boris A.; Zadkov, Victor N. [International Laser Center and Faculty of Physics, M.V. Lomonosov Moscow State University, 119899 Moscow (Russian Federation)

2004-11-01T23:59:59.000Z

256

Catalytic reforming catalyst with modified pore size distribution and a process using the same  

Science Conference Proceedings (OSTI)

This patent describes a catalytic reforming process for conversion of a naptha hydrocarbon at reforming conditions using a catalyst comprising at least one catalytic metal and alumina. The improvement comprises using a catalyst having the following properties in combination: a surface area above about 250 M/sup 2//gram of catalyst; a pore volume above about 0.44 cc/gram of catalyst in pores having diameters of from about 30 angstroms to about 38,000 angstroms; and a pore volume distribution wherein about 70 percent or less of the pore volume is in pores having diameters of from about 30 angstroms to about 400 angstroms. About 30 percent or more pore volume is in pores having diameters of from about 400 angstroms to about 38,000 angstroms.

Unmuth, E.E.; Fleming, B.A.

1987-05-12T23:59:59.000Z

257

Micron-scale droplet deposition on a hydrophobic surface using a retreating syringe  

E-Print Network (OSTI)

Droplet deposition onto a hydrophobic surface is studied experimentally and numerically. A wide range of droplet sizes can result from the same syringe, depending strongly on the needle retraction speed. Three regimes are identified according to the motion of the contact line. In Region I, at slow retraction speeds, the contact line expands and large droplets can be achieved. In Region II, at moderate needle speeds, a quasi-cylindrical liquid bridge forms resulting in drops approximately the size of the needle. Finally, at high speeds (Region III), the contact line retracts and droplets much smaller than the syringe diameter are observed. Scaling arguments are presented identifying the dominant mechanisms in each regime. Results from nonlinear numerical simulations agree well with the experiments, although the accuracy of the predictions is limited by inadequate models for the behavior of the dynamic contact angle.

Qian, Bian; Gagnon, David; Tripathi, Anubhav; Breuer, Kenneth S

2009-01-01T23:59:59.000Z

258

The Impact of Oil Consumption Mechanisms on Diesel Exhaust Particle Size Distributions and Detailed Exhaust Chemical Composition  

DOE Green Energy (OSTI)

Detailed exhaust emission data have been taken from a Cummins N-14 single cylinder research engine in which the oil consumption was varied by different engine modifications. Low sulfur fuel was used, and oil consumption was varied by modifying the intake valve stem seals, the exhaust valve stem seals, the oil control ring and combinations of these modifications. Detailed measurements of exhaust gas particle size distributions and chemical composition were made for the various oil consumption configurations for a range of engine loads and speeds. The particulate mass was measured with TEOM and traditional gravimetric filter methods. Filter data for EC/OC, sulfates and trace metals have been taken and analyzed. The trace metals in the particulate mass serve as the basis for assessing oil consumption at the different operating conditions. The data indicate that the oil consumption for the steady state testing done here was approximately an order of magnitude below oil consumption values cited in the literature. We did measure changes in the details of the chemical composition of the particulate for the different engine operating conditions, but it did not correlate with changes in the oil consumption. Furthermore, the data indicate that the particle size distribution is not strongly impacted by low level oil consumption variations observed in this work.

Stetter, J; Forster, N; Ghandhi, J; Foster, D

2003-08-24T23:59:59.000Z

259

Nematic droplets in aqueous dispersions of carbon nanotubes  

E-Print Network (OSTI)

Aqueous dispersions of exfoliated, bile-salt stabilized single-wall carbon nanotubes exhibit a first order transition to a nematic liquid-crystalline phase. The nematic phase presents itself in the form of micron-sized nematic droplets also known as tactoids, freely floating in the isotropic host dispersion. The nematic droplets are spindle shaped and have an aspect ratio of about four, irrespective of their size. We attribute this to a director field that is uniform rather than bipolar, which is confirmed by polarization microscopy. It follows that the ratio of the anchoring strength and the surface tension must be about four, which is quite larger than predicted theoretically but in line with earlier observations of bipolar tactoids. From the scatter in the data we deduce that the surface tension of the coexisting isotropic and nematic phases must be extremely low, that is, of the order of nN/m.

Nicolas Puech; Eric Grelet; Philippe Poulin; Christophe Blanc; Paul van der Schoot

2013-06-23T23:59:59.000Z

260

Second Blows in the Head-on Collisions of the Spherical Nano Polymer Droplets  

E-Print Network (OSTI)

We report observations of weird but interesting phenomenon from the molecular dynamics simulations, occurrence of second blows in the head-on collisions of two equal-sized spherical nano polymer droplets. In the head-on collisions, we usually expect a single peak of impact forces between two colliding droplets. But, in the simulations, the second peak of the impact forces is actually observed. Its underlying mechanisms at the molecular scale are also proposed.

Sangrak Kim

2013-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Excitation Power Dependence Of Photoluminescence From GaAs Quantum Dot Prepared By Droplet Epitaxy Method  

Science Conference Proceedings (OSTI)

GaAs quantum dot (QD) was grown by droplet epitaxy (DE) method and the excitation power dependence of photoluminescence (PL) were carried out. To investigate the effect of annealing temperature on QDs optical properties, the two step RTA process was carried out in a various temperature range from 800 to 1000 deg. C. As the thermal annealing temperature increases, the PL peak position is blue-shifted due to the change of the composition and size distribution of QDs, and the highest PL intensity is observed at the sample annealed at 900 deg. C. The integrated PL intensity (I{sub PL}) is plotted against the excitation density in a log-log scale and the slope was calculated.

Choi, H. Y.; Kim, D. Y.; Cho, M. Y.; Kim, G. S.; Jeon, S. M.; Yim, K. G.; Kim, M. S.; Leem, J. Y. [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Gimhae (Korea, Republic of); Lee, D. Y. [Epi-manufacturing Technology, Samsung LED Co., Ltd., Suwon (Korea, Republic of); Kim, J. S. [Division of Advanced Materials Engineering, Chonbuk National University, Jeonju (Korea, Republic of); Kim, J. S. [Department of Physics, Yeungnam University, Gyeongsan (Korea, Republic of); Son, J. S. [Department of Visual Optics, Kyungwoon University, Gumi (Korea, Republic of); Lee, J. I. [Advanced Instrument Technology Center, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2011-12-23T23:59:59.000Z

262

Aerosol Size Distribution, Particle Concentration, and Optical Property Variability near Caribbean Trade Cumulus Clouds: Isolating Effects of Vertical Transport and Cloud Processing from Humidification Using Aircraft Measurements  

Science Conference Proceedings (OSTI)

This paper examines the effect of trade wind cumulus clouds on aerosol properties in the near-cloud environment using data from the Rain in Cumulus over the Ocean (RICO) campaign. Aerosol size distributions, particle concentrations, and optical ...

Robert M. Rauber; Guangyu Zhao; Larry Di Girolamo; Marilé Colón-Robles

2013-10-01T23:59:59.000Z

263

Diurnal Variations and Modulation by Easterly Waves of the Size Distribution of Convective Cloud Clusters over West Africa and the Atlantic Ocean  

Science Conference Proceedings (OSTI)

Using Metecosat satellite data in the atmospheric infrared window, the authors study short time-scale fluctuations of the size distribution of tropical convective cloud clusters for July to September 1989. A cluster at a given brightness-...

L. A. Toledo Machado; J-Ph Duvel; M. Desbois

1993-01-01T23:59:59.000Z

264

Determining Size Distributions and Composition of Particles Suspended in Water: A New SEM–EDS Protocol with Validation and Comparison to Other Methods  

Science Conference Proceedings (OSTI)

Knowledge of particle size distributions (PSDs) in seawater is important for understanding several facets of marine science, such as the behavior of light scattering in seawater, phytoplankton dynamics, and biogeochemical cycling. Here, a method ...

Heather Groundwater; Michael S. Twardowski; Heidi M. Dierssen; Antoine Sciandra; Scott A. Freeman

2012-03-01T23:59:59.000Z

265

Particles in the Lower Troposphere over the High Plains of the United States. Part I: Size Distributions, Elemental Compositions and Morphologies  

Science Conference Proceedings (OSTI)

Airborne measurements are presented of particle size distributions obtained during spring and summer at various locations in the High Plains of the United States. Two main particle modes are apparent: an accumulation mode between particle ...

Peter V. Hobbs; David A. Bowdle; Lawrence F. Radke

1985-12-01T23:59:59.000Z

266

An Analysis of Errors in Drop Size Distribution Retrievals and Rain Bulk Parameters with a UHF Wind Profiling Radar and a Two-Dimensional Video Disdrometer  

Science Conference Proceedings (OSTI)

Vertically pointed wind profiling radars can be used to obtain measurements of the underlying drop size distribution (DSD) for a rain event by means of the Doppler velocity spectrum. Precipitation parameters such as rainfall rate, radar ...

Laura Kanofsky; Phillip Chilson

2008-12-01T23:59:59.000Z

267

Estimation of N*0 for the Two-Scale Gamma Raindrop Size Distribution Model and Its Statistical Properties at Several Locations in Asia  

Science Conference Proceedings (OSTI)

An automatic estimation method is developed to detect stepwise changes in the amplitude parameter of the normalized raindrop size distribution (DSD) N*0. To estimate N*0, it is also assumed that the variation of three DSD parameters follows the ...

Toshiaki Kozu; Kazuhiro Masuzawa; Toyoshi Shimomai; Nobuhisa Kashiwagi

2010-04-01T23:59:59.000Z

268

Comparison of Raindrop Size Distribution Measurements by a Joss-Waldvogel Disdrometer, a PMS 2DG Spectrometer, and a POSS Doppler Radar  

Science Conference Proceedings (OSTI)

Three techniques for the measurement of raindrop size distributions are compared using data from a Joss-Waldvogel disdrometer (JWD), a Particle Measuring Systems 2DG spectrometer (PMS), and an Atmospheric Environment Service (AES) Precipitation ...

B. E. Sheppard; P. I. Joe

1994-08-01T23:59:59.000Z

269

Hydrated and Dried Aerosol-Size-Distribution Measurements from the Particle Measuring Systems FSSP-300 Probe and the Deiced PCASP-100X Probe  

Science Conference Proceedings (OSTI)

Comparisons of particle-size distributions measured by Particle Measuring Systems FSSP-300 and PCASP-100X probes through a range of relative humidities reveal that the deiced PCASP-100X probe dries hydrated submicron aerosols before measurement. ...

J. Walter Strapp; W. R. Leaitch; P. S. K. Liu

1992-10-01T23:59:59.000Z

270

Leakage diagnostics, sealant longevity, sizing and technologytransfer in residential thermal distribution systems: Part II.Residential thermal Distribution Systesm, Phase VI FinalReport  

SciTech Connect

This report builds on and extends our previous efforts as described in "Leakage Diagnostics, Sealant Longevity, Sizing and Technology Transfer in Residential Thermal Distribution Systems- CIEE Residential Thermal Distribution Systems Phase V Final Report, October 1997". New developments include defining combined duct and equipment efficiencies in a concept called "Tons At the Register" and on performance issues related to field use of the aerosol sealant technology. Some of the key results discussed in this report include: o Register, boot and air handler cabinet leakage can often represent a significant fraction of the total duct leakage in new construction. Because of the large range of pressures in duct systems an accurate characterization may require separating these components through improved leakage testing. o Conventional duct tape failed our accelerated longevity testing and is not, therefore, considered generally acceptable for use in sealing duct systems. Many other tapes and sealing approaches are available and practical and have passed our longevity tests. o Simulations of summer temperature pull-down time have shown that duct system improvements can be combined with equipment downsizing to save first cost, energy consumption, and peak power and still provide equivalent or superior comfort. o Air conditioner name plate capacity ratings alone are a poor indicator of how much cooling will actually be delivered to the conditioned space. Duct system efficiency can have as large an impact on performance as variations in SEER. o Mechanical duct cleaning techniques do not have an adverse impact on the ducts sealed with the Aerosol sealant. The material typically used in Aerosol sealing techniques does not appear to present a health or safety hazard. Results from this study were used by the California Energy Commission in the formation of the current Energy Efficiency Standards for Low-Rise Residential Buildings (CEC, (1998)), often referred to as Title 24. Current information on ducts and thermal distribution research can be found at http://ducts.lbl.gov

Buchanan, C.; Modera, M.; Sherman, M.; Siegel, J.; Walker, I.; Wang, D.

1998-12-01T23:59:59.000Z

271

A new model of cloud drop distribution that simulates the observed drop  

NLE Websites -- All DOE Office Websites (Extended Search)

A new model of cloud drop distribution that simulates the observed drop A new model of cloud drop distribution that simulates the observed drop clustering: effect of clustering on extinction coefficient estimates Knyazikhin, Yuri Boston University Marshak, Alexander NASA Goddard Space Flight Center Larsen, Michael Michigan Technological University Wiscombe, Warren BNL/NASA Goddard Space Flight Center Category: Modeling Cloud droplet size distribution is one of the most fundamental subjects in cloud physics. Understanding of spatial distribution and small-scale fluctuations of cloud droplets is essential for both cloud physics and atmospheric radiation. For cloud physics, it relates to the coalescence growth of raindrops while for radiation, it has a strong impact on a cloud's radiative properties. We have developed new size dependent models

272

Droplet Growth in Warm Water Clouds Observed by the A-Train. Part II: A Multisensor View  

Science Conference Proceedings (OSTI)

Hydrometeor droplet growth processes are inferred from a combination of Aqua/Moderate Resolution Imaging Spectroradiometer (MODIS) cloud particle size observations and CloudSat/Cloud Profiling Radar (CPR) observations of warm water clouds. This ...

Takashi Y. Nakajima; Kentaroh Suzuki; Graeme L. Stephens

2010-06-01T23:59:59.000Z

273

Droplet Charging Effects in the Space Environment  

Science Conference Proceedings (OSTI)

Several applications exist for transiting liquid droplets through the near-Earth space environment. Numerical results are presented for the charging of liquid droplets of trimethyl pentaphenyl siloxane (DC705) in three different plasma environments: ionosphere, auroral, and geosynchronous Earth orbit (GEO). Nominal and high geomagnetic activity cases are investigated. In general, high levels of droplet charging (>100 V) exist only in GEO during periods of high geomagnetic or solar activity. An experiment was conducted to assess the charging of silicon-oil droplets due to photoemission. The photoemission yield in the 120-200 nm wavelength range was found to be approximately 0.06.

Joslyn, Thomas B. [United States Air Force Academy, Department of Astronautics, USAF Academy, CO 80840 (United States); Ketsdever, Andrew D. [University of Colorado at Colorado Springs, Department of Mechanical and Aerospace Engineering, Colorado, Springs, CO 80918 (United States)

2011-05-20T23:59:59.000Z

274

Universal fluid droplet ejector - Energy Innovation Portal  

A droplet generator comprises a fluid reservoir having a side wall made of glass or quartz, and an end cap made from a silicon plate. The end cap ...

275

Shear-driven redistribution of surfactant affects enzyme activity in well-mixed femtoliter droplets  

SciTech Connect

We developed a microfluidic platform for splitting well-mixed, femtoliter-volume droplets from larger water-in-oil plugs, where the sizes of the daughter droplets were not limited by channel width. These droplets were separated from mother plugs at a microfabricated T-junction, which enabled the study of how increased confinement affected enzyme kinetics in droplets 4-10 {mu}m in diameter. Initial rates for enzyme catalysis in the mother plugs and the largest daughter drops were close to the average bulk rate, while the rates in smaller droplets decreased linearly with increasing surface to volume ratio. Rates in the smallest droplets decreased by a factor of 4 compared to the bulk rate. Traditional methods for detecting nonspecific adsorption at the water-oil interface were unable to detect evidence of enzyme adsorption, including pendant drop tensiometry, laser scanning confocal microscopy of drops containing labeled proteins in microemulsions, and epifluorescence microscopy of plugs and drops generated on-chip. We propose the slowing of enzyme reaction kinetics in the smaller droplets was the result of increased adsorption and inactivation of enzymes at the water-oil interface arising from transient interfacial shear stresses imparted on the daughter droplets as they split from the mother plugs and passed through the constricted opening of the T-junction. Such stresses are known to modulate the interfacial area and density of surfactant molecules that can passivate the interface. Bright field images of the splitting processes at the junction indicate that these stresses scaled with increasing surface to volume ratios of the droplets but were relatively insensitive to the average flow rate of plugs upstream of the junction.

Collier, Pat [ORNL

2009-01-01T23:59:59.000Z

276

First measurement of the small-scale spatial variability of the rain drop size distribution: Results from a crucial experiment and maximum entropy modeling  

E-Print Network (OSTI)

The main challenges of measuring precipitation are related to the spatio-temporal variability of the drop-size distribution, to the uncertainties that condition the modeling of that distribution, and to the instrumental errors present in the in situ estimations. This PhD dissertation proposes advances in all these questions. The relevance of the spatial variability of the drop-size distribution for remote sensing measurements and hydro-meteorology field studies is asserted by analyzing the measurement of a set of disdrometers deployed on a network of 5 squared kilometers. This study comprises the spatial variability of integral rainfall parameters, the ZR relationships, and the variations within the one moment scaling method. The modeling of the drop-size distribution is analyzed by applying the MaxEnt method and comparing it with the methods of moments and the maximum likelihood. The instrumental errors are analyzed with a compressive comparison of sampling and binning uncertainties that affect actual device...

Checa-Garcia, Ramiro

2013-01-01T23:59:59.000Z

277

Holographic droplets in p-wave insulator/superconductor transition  

E-Print Network (OSTI)

In the present paper, based on the notion of marginally stable modes of vector perturbations in the AdS soliton back ground we investigate the magnetic field effect on holographic $ p $- wave insulator/superconductor transition in the probe limit. We perform explicit analytic calculations considering both Schwarzschild AdS soliton and Gauss Bonnet AdS soliton back grounds and obtain a unique relation between the chemical potential and the magnetic field near the critical point. We also extend our analysis for $ p+ip $- wave back ground in the presence of external magnetic field. In both the cases it is observed that the non abelian model exhibit \\textit{droplet} solutions. Moreover it is also found that the increase in the value of the external magnetic field essentially reduces the size of the droplet and thereby makes the condensation harder.

Dibakar Roychowdhury

2013-04-23T23:59:59.000Z

278

Turbulent Condensation of Droplets: Direct Simulation and a Stochastic Model  

Science Conference Proceedings (OSTI)

The effect of turbulent mixing on droplet condensation is studied via direct numerical simulations of a population of droplets in a periodic box of homogeneous isotropic turbulence. Each droplet is tracked as a fluid particle whose radius grows ...

Roberto Paoli; Karim Shariff

2009-03-01T23:59:59.000Z

279

Optimal Siting and Sizing of Solar Photovoltaic Distributed Generation to Minimize Loss, Present Value of Future Asset Upgrades and Peak Demand Costs on a Real Distribution Feeder.  

E-Print Network (OSTI)

??The increasing penetration of distributed generation (DG) in power distribution systems presents technical and economic benefits as well as integration challenges to utility engineers. Governments… (more)

Mukerji, Meghana

2011-01-01T23:59:59.000Z

280

Direct numerical simulation of evaporating droplets  

Science Conference Proceedings (OSTI)

A model for the three-dimensional direct numerical simulation of evaporating, deforming droplets in incompressible flow is presented. It is based on the volume-of-fluid method and is therefore capable of capturing very strong deformations. The evaporation ... Keywords: DNS, Deformed droplets, Evaporation, Multiphase flow, Stefan flow, VOF

Jan Schlottke; Bernhard Weigand

2008-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Oil droplet behavior at a pore entrance in the presence of crossflow: Implications for microfiltration of oil-water dispersions  

E-Print Network (OSTI)

The behavior of an oil droplet pinned at the entrance of a micropore and subject to clossflow-induced shear is investigated numerically by solving the Navier-Stokes equation. We found that in the absence of crossflow, the critical transmembrane pressure required to force the droplet into the pore is in excellent agreement with a theoretical prediction based on the Young-Laplace equation. With increasing shear rate, the critical pressure of permeation increases, and at sufficiently high shear rates the oil droplet breaks up into two segments. The results of numerical simulations indicate that droplet breakup at the pore entrance is facilitated at lower surface tension, higher oil-to-water viscosity ratio and larger droplet size but is insensitive to the value of the contact angle. Using simple force and torque balance arguments, an estimate for the increase in critical pressure due to crossflow and the breakup capillary number is obtained and validated for different viscosity ratios, surface tension coefficien...

Darvishzadeh, Tohid; Priezjev, Nikolai V

2013-01-01T23:59:59.000Z

282

The Occurrence of Particle Size Distribution Bimodality in Midlatitude Cirrus as Inferred from Ground-Based Remote Sensing Data  

SciTech Connect

To better understand the role of small particles in the microphysical processes and the radiative properties of cirrus, the reliability of historical in-situ data must be understood. Recent studies call into question the validity of that data because of shattering of large crystals on probe and aircraft surfaces thereby artificially amplifying the concentration of crystals smaller than approximately 50 ?m. We contend that the general character of the in-situ measurements must be consistent, in a broad sense, with statistics derived from long-term remote sensing data. To examine this consistency, an algorithm using Doppler radar moments and Raman lidar extinction is developed to retrieve a bimodal particle size distribution and its uncertainty. Using case studies and statistics compiled over one year we show that the existence of high concentrations (> 1 cm-3 ) of small (sub 50 ?m) particles in cirrus are not consistent with any reasonable interpretation of the remote sensing data. We conclude that the high concentrations of small particles found in many aircraft data sets are therefore likely an artifact of the in situ measurement process.

Zhao, Yang; Mace, Gerald G.; Comstock, Jennifer M.

2011-06-01T23:59:59.000Z

283

Spreading of a granular droplet.  

Science Conference Proceedings (OSTI)

The influence of controlled vibrations on the granular rheology is investigated in a specifically designed experiment in which a granular film spreads under the action of horizontal vibrations. A nonlinear diffusion equation is derived theoretically that describes the evolution of the deposit shape. A self-similar parabolic shape (the granular droplet) and a spreading dynamics are predicted that both agree quantitatively with the experimental results. The theoretical analysis is used to extract effective friction coefficients between the base and the granular layer under sustained and controlled vibrations. A shear thickening regime characteristic of dense granular flows is evidenced at low vibration energy, both for glass beads and natural sand. Conversely, shear thinning is observed at high agitation.

Sanchez, I.; Raynaud, F.; Lanuza, J.; Andreotti, B.; Clement, E.; Aranson, I. S.; Materials Science Division; Univ. Simon; CNRS-ESPCI-Univ.

2007-01-01T23:59:59.000Z

284

Droplet Impingement Cooling Experiments on Nano-structured Surfaces  

E-Print Network (OSTI)

Spray cooling has proven to be efficient in managing thermal load in high power applications. Reliability of electronic products relies on the thermal management and understanding of heat transfer mechanisms including those related to spray cooling. However, to date, several of the key heat transfer mechanisms are still not well understood. An alternative approach for improving the heat transfer performance is to change the film dynamics through surface modification. The main goal of this study is to understand the effects of nano-scale features on flat heater surfaces subjected to spray cooling and to determine the major factors in droplet impingement cooling to estimate their effects in the spray cooling system. Single droplet stream and simultaneous triple droplet stream with two different stream spacings (500 ?m and 2000 ?m), experiments have been performed to understand the droplet-surface interactions relevant to spray cooling systems. Experiments have been conducted on nano-structured surfaces as well as on flat (smooth) surfaces. It is observed that nano-structured surfaces result in lower minimum wall temperatures, better heat transfer performance, and more uniform temperature distribution. A new variable, effective thermal diameter (de), was defined based on the radial temperature profiles inside the impact zone to quantify the effects of the nano-structured surface in droplet cooling. Results indicate that larger effective cooling area can be achieved using nano-structured surface in the single droplet stream experiments. In triple stream experiments, nano-structured surface also showed an enhanced heat transfer. In single stream experiments, larger outer ring structures (i.e. larger outer diameters) in the impact crater were observed on the nano-structured surfaces which can be used to explain enhanced heat transfer performance. Smaller stream spacing in triple stream experiments reveal that the outer ring structure is disrupted resulting in lower heat transfer. Lower static contact angle on the nano-structured surface has been observed, which implies that changes in surface properties result in enhanced film dynamics and better heat transfer behavior. The results and conclusions of this study should be useful for understanding the physics of spray cooling and in the design of better spray cooling systems.

Lin, Yen-Po

2010-08-01T23:59:59.000Z

285

Direct mechanical energy measures of hammer mill comminution of switchgrass, wheat straw, and corn stover and analysis of their particle size distributions  

Science Conference Proceedings (OSTI)

Biomass particle size impacts handling, storage, conversion, and dust control systems. Size reduction mechanical energy was directly measured for switchgrass (Panicum virgatum L.), wheat straw (Triticum aestivum L.), and corn stover (Zea mays L.) in an instrumented hammer mill. Direct energy inputs were determined for hammer mill operating speeds from 2000 to 3600 rpm for 3.2 mm integral classifying screen and mass input rate of 2.5 kg/min with 90 - and 30 -hammers. Overall accuracy of specific energy measurement was calculated as 0.072 MJ/Mg. Particle size distributions created by hammer mill were determined for mill operating factors using ISO sieve sizes from 4.75 to 0.02 mm in conjunction with Ro-Tap sieve analyzer. A wide range of analytical descriptors were examined to mathematically represent the range of particle sizes in the distributions. Total specific energy (MJ/Mg) was defined as size reduction energy to operate the hammer mill plus that imparted to biomass. Effective specific energy was defined as energy imparted to biomass. Total specific energy for switchgrass, wheat straw, and corn stover grinding increased by 37, 30, and 45% from 114.4, 125.1, and 103.7 MJ/Mg, respectively, with an increase in hammer mill speed from 2000 to 3600 rpm for 90 -hammers. Corresponding total specific energy per unit size reduction was 14.9, 19.7, and 13.5 MJ/Mg mm, respectively. Effective specific energy of 90 -hammers decreased marginally for switchgrass and considerably for wheat straw and it increased for corn stover with an increase in speed from 2000 to 3600 rpm. However, effective specific energy increased with speed to a certain extent and then decreased for 30 -hammers. Rosin Rammler equation fitted the size distribution data with R2 > 0.995. Mass relative span was greater than 1, which indicated a wide distribution of particle sizes. Hammer milling of switchgrass, wheat straw, and corn stover with 3.2 mm screen resulted in well-graded fine-skewed mesokurtic particles. Uniformity coefficient was corn stover, which indicated a moderate assortment of particles. Size-related parameters, namely, geometric mean diameter, Rosin Rammler size parameter, median diameter, and effective size had strong correlation among themselves and good negative correlation with speed. Distribution-related parameters, namely, Rosin Rammler distribution parameter, mass relative span, inclusive graphic skewness, graphic kurtosis, uniformity index, uniformity coefficient, coefficient of gradation and distribution geometric standard deviation had strong correlation among themselves and a weak correlation with mill speed. Results of this extensive analysis of specific energy and particle sizes can be applied to selection of hammer mill operating factors to produce a particular size of switchgrass, wheat straw, and corn stover grind, and will serve as a guide for relations among the energy and various analytic descriptors of biomass particle distributions.

Bitra, V.S.P [University of Tennessee; Womac, A.R. [University of Tennessee; Chevanan, Nehru [University of Tennessee; Miu, P.I. [University of Tennessee; Smith, D.R. [University of Tennessee; Igathinathane, C. [Mississippi State University (MSU); Sokhansanj, Shahabaddine [ORNL

2009-07-01T23:59:59.000Z

286

Theoretical studies on hydrogen ignition and droplet combustion  

E-Print Network (OSTI)

1.2 Droplet Combustion . . . . . . . . . . . . .Combustion . . . . . . . . . . . . . . . . . . . . . . . . . .Lewis, B. and von Elbe, G. Combustion, Flames and Explosions

Del Álamo, Gonzalo

2006-01-01T23:59:59.000Z

287

Alpha spectrometric characterization of process-related particle size distributions from active particle sampling at the Los Alamos National Laboratory uranium foundry  

SciTech Connect

Uranium particles within the respirable size range pose a significant hazard to the health and safety of workers. Significant differences in the deposition and incorporation patterns of aerosols within the respirable range can be identified and integrated into sophisticated health physics models. Data characterizing the uranium particle size distribution resulting from specific foundry-related processes are needed. Using personal air sampling cascade impactors, particles collected from several foundry processes were sorted by activity median aerodynamic diameter onto various Marple substrates. After an initial gravimetric assessment of each impactor stage, the substrates were analyzed by alpha spectrometry to determine the uranium content of each stage. Alpha spectrometry provides rapid nondestructive isotopic data that can distinguish process uranium from natural sources and the degree of uranium contribution to the total accumulated particle load. In addition, the particle size bins utilized by the impactors provide adequate resolution to determine if a process particle size distribution is: lognormal, bimodal, or trimodal. Data on process uranium particle size values and distributions facilitate the development of more sophisticated and accurate models for internal dosimetry, resulting in an improved understanding of foundry worker health and safety.

Plionis, Alexander A [Los Alamos National Laboratory; Peterson, Dominic S [Los Alamos National Laboratory; Tandon, Lav [Los Alamos National Laboratory; Lamont, Stephen P [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

288

Unified formulation of single and multi-moment normalizations of the raindrop size distribution based on the gamma probability density function  

Science Conference Proceedings (OSTI)

This study offers a unified formulation of single and multi-moment normalizations of the raindrop size distribution (DSD), which have been proposed in the framework of scaling analyses in the literature. The key point is to consider a well-defined ...

Nan Yu; Guy Delrieu; Brice Boudevillain; Pieter Hazenberg; Remko Uijlenhoet

289

A Microcomputer Data-Acquisition System for Real-Time Processing of Raindrop Size Distribution Measured with the RD69 Distrometer  

Science Conference Proceedings (OSTI)

The disdrometer is an instrument used worldwide to measure the size distribution of raindrops at ground level. In this paper, a data-acquisition and real-time processing system designed for disdrometer measurements is presented. It is based on a ...

Bernard Campistron; Gilbert Despaux; Jean-Pierre Lacaux

1987-09-01T23:59:59.000Z

290

Aircraft Icing Caused by Large Supercooled Droplets  

Science Conference Proceedings (OSTI)

The characteristic of aircraft icing environments containing large supercooled droplets are described. Substantial loss in rate of climb capability can result from less than 10 minutes duration in conditions where fewer than 0.1–1 cm?3 of ...

Marcia K. Politovich

1989-09-01T23:59:59.000Z

291

Droplets bouncing on a wet, inclined surface  

E-Print Network (OSTI)

We present the results of an experimental investigation of fluid drops impacting an inclined rigid surface covered with a thin layer of high viscosity fluid. We deduce the conditions under which droplet bouncing, splitting, ...

Gilet, Tristan

292

Entropic Aspects of Supercooled Droplet Freezing  

Science Conference Proceedings (OSTI)

The freezing of supercooled water droplets in the atmosphere, with an emphasis on the entropic aspects of the problem, is examined. Supercooled water is a metastable state and, therefore, the associated phase transition must be irreversible. ...

Alexander Kostinski; Will Cantrell

2008-09-01T23:59:59.000Z

293

The Impact of Ice Crystal Shapes, Size Distributions, and Spatial Structures of Cirrus Clouds on Solar Radiative Fluxes  

Science Conference Proceedings (OSTI)

The solar radiative properties of cirrus clouds depend on ice particle shape, size, and orientation, as well as on the spatial cloud structure. Radiation schemes in atmospheric circulation models rely on estimates of cloud optical thickness only. ...

I. Schlimme; A. Macke; J. Reichardt

2005-07-01T23:59:59.000Z

294

Collision, Coalescence and Breakup of Raindrops. Part I: Experimentally Established Coalescence Efficiencies and Fragment Size Distributions in Breakup  

Science Conference Proceedings (OSTI)

The collision, coalescence and breakup of single raindrop pairs were studied at terminal velocities and laboratory pressure (100 kPa) in 761 collision experiments (out of 14 000 attempts). Six size combinations were used with drop pair diameters ...

T. B. Low; Roland List

1982-07-01T23:59:59.000Z

295

On the Aerosol Particle Size Distribution Spectrum in Alaskan Air Mass Systems: Arctic Haze and Non-Haze Episodes  

Science Conference Proceedings (OSTI)

Aerosols in central Alaskan winter air mass system were classified according to size by diffusive separation and light-scattering spectrometry. Particles entering central Alaska from the Pacific Marine environment had number concentrations ...

Glenn E. Shaw

1983-05-01T23:59:59.000Z

296

Evaluation of a 45° Slant Quasi-Linear Radar Polarization State for Distinguishing Drizzle Droplets, Pristine Ice Crystals, and Less Regular Ice Particles  

Science Conference Proceedings (OSTI)

A remote sensing capability is needed to detect clouds of supercooled, drizzle-sized droplets, which are a major aircraft icing hazard. Discrimination among clouds of differing ice particle types is also important because both the presence and ...

Roger F. Reinking; Sergey Y. Matrosov; Robert A. Kropfli; Bruce W. Bartram

2002-03-01T23:59:59.000Z

297

Effective Radius of Cloud Droplets by Ground-Based Remote Sensing: Relationships to Aerosol?  

NLE Websites -- All DOE Office Websites (Extended Search)

Effective Radius of Cloud Droplets by Ground-Based Effective Radius of Cloud Droplets by Ground-Based Remote Sensing: Relationships to Aerosol? B.-G. Kim, S. E. Schwartz, and M. A. Miller Environmental Sciences Department Brookhaven National Laboratory Upton, New York Q.-L. Min Atmospheric Science Research Center State University of New York Albany, New York Introduction Aerosol Indirect Effect Increases in anthropogenic sources of cloud condensation nuclei can increase cloud albedo by increasing the concentration and reducing the size of cloud droplets, usually referred to as the indirect effect of aerosol on climate (Twomey 1977). However, the magnitudes of the various kinds of indirect forcing are particularly uncertain, because they involve subtle changes in cloud radiative properties and lifetimes

298

Investigation of the particle size distribution and particle density characteristics of Douglas fir hogged fuel fly ash collected under known combustion conditions. Technical Progress Report No. 2  

DOE Green Energy (OSTI)

The increased interest in wood as a fuel source, coupled with the increasing demand to control the emission generated by wood combustion, has created a need for information characterizing the emissions that occur for given combustion conditions. This investigation characterizes the carbon char and inorganic fly ash size and density distribution for each of thirty-eight Douglas fir bark samples collected under known conditions of combustion.

Lang, A.J.; Junge, D.C.

1978-12-01T23:59:59.000Z

299

Microphysical Structure of the Marine Atmospheric Mixed Layer under Strong Wind and Sea-Spray Formation as seen from a 2-D Explicit Microphysical Model. Part III: Parameterization of Height-Dependent Droplet Size Distribution  

Science Conference Proceedings (OSTI)

This paper completes a series of studies using a 2-D hybrid Lagrangian-Eulerian model to investigate the effect of sea spray on the thermodynamics and microphysics of the hurricane mixed layer. The evolution of the mixed layer was simulated by ...

J. Shpund; J. A. Zhang; M. Pinsky; A. Khain

300

A Bayesian Approach to Upscaling and Downscaling of Aircraft Measurements of Ice Particle Counts and Size Distributions  

Science Conference Proceedings (OSTI)

This study addresses the issue of how to upscale cloud-sized in situ measurements of ice to yield realistic simulations of ice clouds for a variety of modeling studies. Aircraft measurements of ice particle counts along a 79 km zigzag path were ...

A. R. Jameson; A. J. Heymsfield

Note: This page contains sample records for the topic "droplet size distribution" 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

A Bayesian Approach to Upscaling and Downscaling of Aircraft Measurements of Ice Particle Counts and Size Distributions  

Science Conference Proceedings (OSTI)

This study addresses the issue of how to upscale cloud-sized in situ measurements of ice to yield realistic simulations of ice clouds for a variety of modeling studies. Aircraft measurements of ice particle counts along a 79-km zigzag path were ...

A. R. Jameson; A. J. Heymsfield

2013-09-01T23:59:59.000Z

302

Molecular Thermodynamic Modeling of Droplet-Type Microemulsions  

E-Print Network (OSTI)

Molecular Thermodynamic Modeling of Droplet-Type Microemulsions Livia A. Moreira and Abbas a molecular thermodynamic theory for droplet-type microemulsions, both water-in-oil and oil

Firoozabadi, Abbas

303

Cloud Droplet Growth by Condensation in Homogeneous Isotropic Turbulence  

Science Conference Proceedings (OSTI)

The growth of cloud droplets by diffusion of water vapor in a three-dimensional homogeneous isotropic turbulent flow is considered. Within a simple model of advection and condensation, the dynamics and growth of millions of droplets are ...

Alessandra S. Lanotte; Agnese Seminara; Federico Toschi

2009-06-01T23:59:59.000Z

304

Collision Rates of Cloud Droplets in Turbulent Flow  

Science Conference Proceedings (OSTI)

Direct numerical simulations of an evolving turbulent flow field have been performed to explore how turbulence affects the motion and collisions of cloud droplets. Large numbers of droplets are tracked through the flow field and their positions, ...

Charmaine N. Franklin; Paul A. Vaillancourt; M. K. Yau; Peter Bartello

2005-07-01T23:59:59.000Z

305

System Size, Energy and Centrality Dependence of Pseudorapidity Distributions of Charged Particles in Relativistic Heavy Ion Collisions  

E-Print Network (OSTI)

We present the first measurements of the pseudorapidity distribution of primary charged particles in Cu+Cu collisions as a function of collision centrality and energy, \\sqrtsnn = 22.4, 62.4 and 200 GeV, over a wide range of pseudorapidity, using the PHOBOS detector. Making a global comparison of Cu+Cu and Au+Au results, we find that the total number of produced charged particles and the rough shape (height and width) of the pseudorapidity distributions are determined by the number of nucleon participants. More detailed studies reveal that a more precise matching of the shape of the Cu+Cu and Au+Au pseudorapidity distributions over the full range of pseudorapidity occurs for the same Npart/2A value rather than the same Npart value. In other words, it is the collision geometry rather than just the number of nucleon participants that drives the detailed shape of the pseudorapidity distribution and its centrality dependence at RHIC energies.

B. Alver; B. B. Back; M. D. Baker; M. Ballintijn; D. S. Barton; R. R. Betts; R. Bindel; W. Busza; Z. Chai; V. Chetluru; E. García; T. Gburek; K. Gulbrandsen; J. Hamblen; I. Harnarine; C. Henderson; D. J. Hofman; R. S. Hollis; R. Ho?y?ski; B. Holzman; A. Iordanova; J. L. Kane; P. Kulinich; C. M. Kuo; W. Li; W. T. Lin; C. Loizides; S. Manly; A. C. Mignerey; R. Nouicer; A. Olszewski; R. Pak; C. Reed; E. Richardson; C. Roland; G. Roland; J. Sagerer; I. Sedykh; C. E. Smith; M. A. Stankiewicz; P. Steinberg; G. S. F. Stephans; A. Sukhanov; A. Szostak; M. B. Tonjes; A. Trzupek; G. J. van Nieuwenhuizen; S. S. Vaurynovich; R. Verdier; G. I. Veres; P. Walters; E. Wenger; D. Willhelm; F. L. H. Wolfs; B. Wosiek; K. Wo?niak; S. Wyngaardt; B. Wys?ouch

2007-09-25T23:59:59.000Z

306

The spatial distribution of mineral dust and its shortwave radiative forcing over North Africa: Modeling sensitivities to dust emissions and aerosol size treatments  

Science Conference Proceedings (OSTI)

A fully coupled meteorology-chemistry-aerosol model (WRF-Chem) with the implementation of two dust emission schemes (GOCART and DUSTRAN) into two aerosol models (MADE/SORGAM and MOSAIC) is applied over North Africa to investigate the modeling sensitivities to dust emissions and aerosol size treatments in simulating mineral dust and its shortwave (SW) radiative forcing. Model results of the spatial distribution of mineral dust and its radiative forcing are evaluated using measurements from the AMMA SOP0 campaign in January and February of 2006 over North Africa. Our study suggests that the size distribution of emitted dust can result in significant differences (up to 100%) in simulating mineral dust and its SW radiative forcing. With the same dust emission and dry deposition processes, two aerosol models, MADE/SORGAM and MOSAIC, can yield large difference in size distributions of dust particles due to their different aerosol size treatments using modal and sectional approaches respectively. However, the difference between the two aerosol models in simulating the mass concentrations and the SW radiative forcing of mineral dust is small (< 10%). The model simulations show that mineral dust increases AOD by a factor of 2, heats the lower atmosphere (1-3 km) with a maximum rate of 0.7?0.5 K day-1 below 1 km, and reduces the downwelling SW radiation by up to 25 W m-2 on 24-hour average at surface, highlighting the importance of including dust radiative impact in understanding the regional climate of North Africa. When compared to the available measurements, WRF-Chem simulations can generally capture the measured features of mineral dust and its radiative properties over North Africa, suggesting that the model can be used to perform more extensive simulations of regional climate over North Africa.

Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.; Johnson, Ben; McFarlane, Sally A.; Gustafson, William I.; Fast, Jerome D.; Easter, Richard C.

2010-09-20T23:59:59.000Z

307

Interfacial controlled fusion of individual femtoliter droplets on ...  

This disclosure describes a passive method for on-demand control of femtoliter-volume droplet formation and fusion,

308

Marine Fog Droplets and Salt Nuclei -Part 11  

Science Conference Proceedings (OSTI)

In Past 1 of this fog study, the distribution of water with number and size of drops in some New England marine advection fogs was shown to be related to the distribution of number and size of salt particles found in marine air. It was indicated ...

Alfred H. Woodcock; Duncan C. Blanchard; James E. Jiusto

1981-01-01T23:59:59.000Z

309

Sensitivity of the First Indirect Aerosol Effect to an Increase of Cloud Droplet Spectral Dispersion with Droplet Number Concentration  

Science Conference Proceedings (OSTI)

Observations show that an increase in anthropogenic aerosols leads to concurrent increases in the cloud droplet concentration and the relative dispersion of the cloud droplet spectrum, other factors being equal. It has been suggested that the ...

Leon D. Rotstayn; Yangang Liu

2003-11-01T23:59:59.000Z

310

Evidence for departure from a power-law flare size distribution for a small solar active region  

E-Print Network (OSTI)

Active region 11029 was a small, highly flare-productive solar active region observed at a time of extremely low solar activity. The region produced only small flares: the largest of the $>70$ Geostationary Observational Environmental Satellite (GOES) events for the region has a peak 1--$8{\\AA}$ flux of $2.2\\times 10^{-6} {\\rm W} {\\rm m}^{-2}$ (GOES C2.2). The background-subtracted GOES peak-flux distribution suggests departure from power-law behavior above $10^{-6} {\\rm W} {\\rm m}^{-2}$, and a Bayesian model comparison strongly favors a power-law plus rollover model for the distribution over a simple power-law model. The departure from the power law is attributed to this small active region having a finite amount of energy. The rate of flaring in the region varies with time, becoming very high for two days coinciding with the onset of an increase in complexity of the photospheric magnetic field. The observed waiting-time distribution for events is consistent with a piecewise-constant Poisson model. These res...

Wheatland, M S

2010-01-01T23:59:59.000Z

311

Visualization of Electrohydrodynamic Effects and Time Scale Analysis for Impinging Spray Droplets of HFE-7000  

SciTech Connect

Spray cooling is becoming a leading technique for removing excess heat from high heat flux electronics. Electrohydrodynamic effects have been found to result in significant variation in spray behavior once the applied voltage level is increased enough to reach the Rayleigh limit. In the present work the dielectric coolant HFE-7000 has been used to study spray cooling heat transfer across a thick film resistor heater mounted to a 16 mm diameter pedestal. Heater power levels have been varied from 0 to 80 Watts, with spray flow rates varied from 2 GPH to 6 GPH (2.1x10{sup -6} m{sup 3}/s to 6.3x10{sup -6} m{sup 3}/s). Applied voltage levels between 0 kV and 30 kV with both positive and negative polarity have been applied directly to the brass spray nozzle, resulting in contact charging of the spray. A high-speed video camera was used to study behavior of both the impinging spray and the liquid film that formed on the heater surface. The contact charging was observed to lead to electrostatic atomization or 'breakup' of the droplets. Time scale estimates of the various physical processes within the spray and the liquid film based on the average droplet size have indicated that the time between droplet impacts falling into a crater from a previous droplet is the shortest time scale, which will limit the amount of heat transfer that may take place during spray cooling. However, the observed time between large droplet impacts onto the same heater surface location is comparable to the computed time to heat and vaporize a large drop, indicating a new explanation for the onset of spray cooling CHF: localized dryout of the original large droplet impact craters.

Kreitzer, Paul J.; Kuhlman, John M. [Department of Mechanical and Aerospace Engineering West Virginia University, Morgantown, WV 26506-6106 (United States)

2008-01-21T23:59:59.000Z

312

An interface tracking model for droplet electrocoalescence.  

SciTech Connect

This report describes an Early Career Laboratory Directed Research and Development (LDRD) project to develop an interface tracking model for droplet electrocoalescence. Many fluid-based technologies rely on electrical fields to control the motion of droplets, e.g. microfluidic devices for high-speed droplet sorting, solution separation for chemical detectors, and purification of biodiesel fuel. Precise control over droplets is crucial to these applications. However, electric fields can induce complex and unpredictable fluid dynamics. Recent experiments (Ristenpart et al. 2009) have demonstrated that oppositely charged droplets bounce rather than coalesce in the presence of strong electric fields. A transient aqueous bridge forms between approaching drops prior to pinch-off. This observation applies to many types of fluids, but neither theory nor experiments have been able to offer a satisfactory explanation. Analytic hydrodynamic approximations for interfaces become invalid near coalescence, and therefore detailed numerical simulations are necessary. This is a computationally challenging problem that involves tracking a moving interface and solving complex multi-physics and multi-scale dynamics, which are beyond the capabilities of most state-of-the-art simulations. An interface-tracking model for electro-coalescence can provide a new perspective to a variety of applications in which interfacial physics are coupled with electrodynamics, including electro-osmosis, fabrication of microelectronics, fuel atomization, oil dehydration, nuclear waste reprocessing and solution separation for chemical detectors. We present a conformal decomposition finite element (CDFEM) interface-tracking method for the electrohydrodynamics of two-phase flow to demonstrate electro-coalescence. CDFEM is a sharp interface method that decomposes elements along fluid-fluid boundaries and uses a level set function to represent the interface.

Erickson, Lindsay Crowl

2013-09-01T23:59:59.000Z

313

Irreversible volume growth in polymer-bonded powder systems: effects of crystalline anisotropy, particle size distribution, and binder strength  

Science Conference Proceedings (OSTI)

Pressed-powdered crystallites of intrinsically anisotropic materials have been shown to undergo irreversible volume expansion when subjected to repeated cycles of heating and cooling. We develop a coarse-grained (micron-scale) interaction Hamiltonian for this system and perform molecular dynamics simulations, which quantitatively reproduce the experimentally observed irreversible growth. The functional form and values of the interaction parameters at the coarse-grained level are motivated by our knowledge at the atomic/molecular scale, and allows a simple way to incorporate the effect of polymeric binder. We demonstrate that irreversible growth happens only in the presence of intrinsic crystalline anisotropy of the powder material, is mediated by particles much smaller than the average crystallite size, and can be significantly reduced in the presence of high-strength polymeric binder with elevated glass transition temperatures.

Maiti, A; Gee, R H; Hoffman, D; Fried, L E

2007-08-22T23:59:59.000Z

314

Analysis of transport mechanisms in dense fuel droplet sprays  

DOE Green Energy (OSTI)

This report deals with numerical analyses of fluid mechanics, heat transfer, mass transfer and particle dynamics of interacting spheres and vaporizing droplets in a linear array or on a 1-D trajectory. Available finite element software has been modified and extended to solve several case studies including closely spaced monodisperse spheres with or without blowing; closely spaced vaporizing fuel droplets; and dynamically interacting vaporizing fuel droplets on a 1-D trajectory. Axisymmetric laminar flow has been assumed for three statically or dynamically interacting spherical solids and vaporizing droplets. Emphasis in this work is evaluating the effects of key system parameters, such as free stream Reynolds number, interparticle spacings, liquid/gas-phase viscosity ratio and variable fluid properties, on interfacial transfer processes and on the particle Nusselt number, vaporization rate and drag coefficient. Computer-generated correlations between integral quantities and system parameters were postulated for blowing spheres and vaporizing droplets. In addition to initial Reynolds number and droplet spacings, variable fluid properties, liquid-phase heating and internal droplet circulation have strong effect on the dynamic behavior of multi-droplet systems. While the lead droplet is most significantly affected by all key parameters, the second and third droplet causes distinct interaction effects which are largely dependent on initial droplet spacings. Applications include spherical-structure/fluid-flow interactions, as well as interacting vaporizing droplets in different sprays related to propulsion systems, irrigation, spray coating, etc. Focusing on fuel droplet sprays, results of the dynamic multi-droplet study can assist in better atomizers and combustion chamber designs which may lead to improved combustion efficiencies, smaller/lighter systems, and reduced pollutant emissions.

Kleinstreuer, C.

1991-05-01T23:59:59.000Z

315

Multiscale modeling of the influence of Fe content in a Al-Si-Cu alloy on the size distribution of intermetallic phases and micropores  

Science Conference Proceedings (OSTI)

A multiscale model was developed to simulate the formation of Fe-rich intermetallics and pores in quaternary Al-Si-Cu-Fe alloys. At the microscale, the multicomponent diffusion equations were solved for multiphase (liquid-solid-gas) materials via a finite difference framework to predict microstructure formation. A fast and robust decentered plate algorithm was developed to simulate the strong anisotropy of the solid/liquid interfacial energy for the Fe-rich intermetallic phase. The growth of porosity was controlled by local pressure drop due to solidification and interactions with surrounding solid phases, in addition to hydrogen diffusion. The microscale model was implemented as a subroutine in a commercial finite element package, producing a coupled multiscale model. This allows the influence of varying casting conditions on the Fe-rich intermetallics, the pores, and their interactions to be predicted. Synchrotron x-ray tomography experiments were performed to validate the model by comparing the three-dimensional morphology and size distribution of Fe-rich intermetallics as a function of Fe content. Large platelike Fe-rich {beta} intermetallics were successfully simulated by the multiscale model and their influence on pore size distribution in shape castings was predicted as a function of casting conditions.

Wang Junsheng; Lee, Peter D. [Department of Materials, Imperial College London, South Kensington Campus, Prince Consort Road, London SW7 2AZ (United Kingdom); Li Mei; Allison, John [Materials Research and Advanced Engineering Department, Ford Research Laboratory, Dearborn, Michigan 48121-2053 (United States)

2010-03-15T23:59:59.000Z

316

Net Metering Policy Development and Distributed Solar Generation in Minnesota: Overview of Trends in Nationwide Policy Development and Implications of Increasing the Eligible System Size Cap  

DOE Green Energy (OSTI)

The goal of the Minnesota net metering policy is to give the maximum possible encouragement to distributed generation assets, especially solar electric systems (MN 2008). However, according to a published set of best practices (NNEC 2008) that prioritize the maximum development of solar markets within states, the Minnesota policy does not incorporate many of the important best practices that may help other states transform their solar energy markets and increase the amount of grid-connected distributed solar generation assets. Reasons cited include the low system size limit of 40kW (the best practices document recommends a 2 MW limit) and a lack of language protecting generators from additional utility fees. This study was conducted to compare Minnesota's policies to national best practices. It provides an overview of the current Minnesota policy in the context of these best practices and other jurisdictions' net metering policies, as well as a qualitative assessment of the impacts of raising the system size cap within the policy based on the experiences of other states.

Doris, E.; Busche, S.; Hockett, S.

2009-12-01T23:59:59.000Z

317

Oil droplet behavior at a pore entrance in the presence of crossflow: Implications for microfiltration of oil-water dispersions  

E-Print Network (OSTI)

The behavior of an oil droplet pinned at the entrance of a micropore and subject to clossflow-induced shear is investigated numerically by solving the Navier-Stokes equation. We found that in the absence of crossflow, the critical transmembrane pressure required to force the droplet into the pore is in excellent agreement with a theoretical prediction based on the Young-Laplace equation. With increasing shear rate, the critical pressure of permeation increases, and at sufficiently high shear rates the oil droplet breaks up into two segments. The results of numerical simulations indicate that droplet breakup at the pore entrance is facilitated at lower surface tension, higher oil-to-water viscosity ratio and larger droplet size but is insensitive to the value of the contact angle. Using simple force and torque balance arguments, an estimate for the increase in critical pressure due to crossflow and the breakup capillary number is obtained and validated for different viscosity ratios, surface tension coefficients, contact angles, and drop-to-pore size ratios.

Tohid Darvishzadeh; Volodymyr V. Tarabara; Nikolai V. Priezjev

2013-06-10T23:59:59.000Z

318

Ice Nucleation and Droplet Formation by Bare and Coated Soot Particles  

Science Conference Proceedings (OSTI)

We have studied ice formation at temperatures relevant to homogeneous and heterogeneous ice nucleation, as well as droplet activation and hygroscopicity, of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied to span an atmospherically relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation, with a comparison to a mineral dust particle that acts as an efficient ice nucleus, and particle hygroscopicity. At 253K and 243K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, only droplet formation was observed. At 233K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles, but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude that both uncoated and coated soot particles representative of those generated in our studies are unlikely to significantly contribute to the global budget of heterogeneous ice nuclei at temperatures between 233K and 253K.

Friedman, Beth J.; Kulkarni, Gourihar R.; Beranek, Josef; Zelenyuk, Alla; Thornton, Joel A.; Cziczo, Daniel J.

2011-09-13T23:59:59.000Z

319

Ice Nucleation and Droplet Formation by Bare and Coated Black Carbon Particles  

SciTech Connect

We have studied the ice formation at heterogeneous and homogeneous temperatures, as well as droplet activation and hygroscopicity of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied to span a relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation with a comparison to a well characterized mineral dust particle that acts as an efficient ice nucleus, as well as particle hygroscopicity. At 253K and 243K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, droplet formation was observed. At 233K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles, but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude from our studies that both uncoated and coated soot particles are unlikely to contribute to the global budget of heterogeneous ice nuclei at temperatures between 233K and 253K.

Friedman, Beth J.; Kulkarni, Gourihar R.; Beranek, Josef; Zelenyuk, Alla; Thornton, Joel A.; Cziczo, Daniel J.

2011-10-13T23:59:59.000Z

320

Computational Fluid Dynamics of rising droplets  

SciTech Connect

The main goal of this study is to perform simulations of droplet dynamics using Truchas, a LANL-developed computational fluid dynamics (CFD) software, and compare them to a computational study of Hysing et al.[IJNMF, 2009, 60:1259]. Understanding droplet dynamics is of fundamental importance in liquid-liquid extraction, a process used in the nuclear fuel cycle to separate various components. Simulations of a single droplet rising by buoyancy are conducted in two-dimensions. Multiple parametric studies are carried out to ensure the problem set-up is optimized. An Interface Smoothing Length (ISL) study and mesh resolution study are performed to verify convergence of the calculations. ISL is a parameter for the interface curvature calculation. Further, wall effects are investigated and checked against existing correlations. The ISL study found that the optimal ISL value is 2.5{Delta}x, with {Delta}x being the mesh cell spacing. The mesh resolution study found that the optimal mesh resolution is d/h=40, for d=drop diameter and h={Delta}x. In order for wall effects on terminal velocity to be insignificant, a conservative wall width of 9d or a nonconservative wall width of 7d can be used. The percentage difference between Hysing et al.[IJNMF, 2009, 60:1259] and Truchas for the velocity profiles vary from 7.9% to 9.9%. The computed droplet velocity and interface profiles are found in agreement with the study. The CFD calculations are performed on multiple cores, using LANL's Institutional High Performance Computing.

Wagner, Matthew [Lake Superior State University; Francois, Marianne M. [Los Alamos National Laboratory

2012-09-05T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

The Impact of Size Distribution Assumptions in a Bulk One-Moment Microphysics Scheme on Simulated Surface Precipitation and Storm Dynamics during a Low-Topped Supercell Case in Belgium  

Science Conference Proceedings (OSTI)

In this research the impact of modifying the size distribution assumptions of the precipitating hydrometeors in a bulk one-moment microphysics scheme on simulated surface precipitation and storm dynamics has been explored for long-lived low-topped ...

Kwinten Van Weverberg; Nicole P. M. van Lipzig; Laurent Delobbe

2011-04-01T23:59:59.000Z

322

Comparison of Drop Size Distribution Parameter (D0) and Rain Rate from S-Band Dual-Polarized Ground Radar, TRMM Precipitation Radar (PR), and Combined PR–TMI: Two Events from Kwajalein Atoll  

Science Conference Proceedings (OSTI)

The estimation of the drop size distribution parameter [median volume diameter (D0)] and rain rate (R) from the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) as well as from combined PR–TRMM Microwave Imager (TMI) algorithms ...

V. N. Bringi; Gwo-Jong Huang; S. Joseph Munchak; Christian D. Kummerow; David A. Marks; David B. Wolff

2012-11-01T23:59:59.000Z

323

Distribution:  

Office of Legacy Management (LM)

JAN26 19% JAN26 19% Distribution: OR00 Attn: h.H.M.Roth DFMusser ITMM MMMann INS JCRyan FIw(2) Hsixele SRGustavson, Document rocm Formal file i+a@mmm bav@ ~@esiaw*cp Suppl. file 'Br & Div rf's s/health (lic.only) UNITED STATES ATOMIC ENERGY COMMISSION SPECIAL NUCLEAB MATERIAL LICENSE pursuant to the Atomic Energy Act of 1954 and Title 10, Code of Federal Regulations, Chapter 1, P&t 70, "Special Nuclear Material Reg)llatiqm," a license is hereby issued a$hortztng the licensee to rekeive and possess the special nuclear material designated below; to use such special nuclear mat&ial for the purpose(s) and at the place(s) designated below; and to transfer such material to per&s authorized to receive it in accordance with the regula,tions in said Part.

324

Residence Time and Heat Transfer When Water Droplets Hit a Scalding Ji Yong Park*  

E-Print Network (OSTI)

1 Residence Time and Heat Transfer When Water Droplets Hit a Scalding Surface Ji Yong Park* , Chang a series of water droplets impact a smooth surface whose temperature exceeds the boiling point. The volume of the individual water droplets is 10 nL, the time between droplets is 0.3 ms, and the number of water droplets

Cahill, David G.

325

Modeling Corrosion of a Metal under an Aerosol Droplet  

Science Conference Proceedings (OSTI)

Deposition of aerosol droplets produced either by marine or industrial activity on the ... The atmospheric corrosion caused by aerosols is a result of a complex ...

326

COAGULATION CALCULATIONS OF ICY PLANET FORMATION AT 15-150 AU: A CORRELATION BETWEEN THE MAXIMUM RADIUS AND THE SLOPE OF THE SIZE DISTRIBUTION FOR TRANS-NEPTUNIAN OBJECTS  

Science Conference Proceedings (OSTI)

We investigate whether coagulation models of planet formation can explain the observed size distributions of trans-Neptunian objects (TNOs). Analyzing published and new calculations, we demonstrate robust relations between the size of the largest object and the slope of the size distribution for sizes 0.1 km and larger. These relations yield clear, testable predictions for TNOs and other icy objects throughout the solar system. Applying our results to existing observations, we show that a broad range of initial disk masses, planetesimal sizes, and fragmentation parameters can explain the data. Adding dynamical constraints on the initial semimajor axis of 'hot' Kuiper Belt objects along with probable TNO formation times of 10-700 Myr restricts the viable models to those with a massive disk composed of relatively small (1-10 km) planetesimals.

Kenyon, Scott J. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Bromley, Benjamin C., E-mail: skenyon@cfa.harvard.edu, E-mail: bromley@physics.utah.edu [Department of Physics, University of Utah, 201 JFB, Salt Lake City, UT 84112 (United States)

2012-03-15T23:59:59.000Z

327

Numerical simulation of cloud droplet formation in a tank  

Science Conference Proceedings (OSTI)

Using the computational fluid dynamics (CFD) code FLUENT 6 together with the fine particle model (FPM), numerical simulations of droplet dynamics in a 12.4m^3 cloud tank were conducted. The coupled fields of water vapor, temperature, flow velocity, particle ... Keywords: Cloud droplet formation, Particle-dynamics modeling, Stirred tank, Turbulence

Matthias Schütze; Frank Stratmann

2008-09-01T23:59:59.000Z

328

OIL DROPLET MANIPULATION USING LIQUID DIELECTROPHORESIS ON ELECTRET WITH SUPERLYOPHOBIC  

E-Print Network (OSTI)

OIL DROPLET MANIPULATION USING LIQUID DIELECTROPHORESIS ON ELECTRET WITH SUPERLYOPHOBIC SURFACES flow friction for water and oil. Charge stability of electret in liquid is much improved with new hysteresis of SLS for oil droplets are experimentally demonstrated, indicating low motion resistance

Kasagi, Nobuhide

329

3D Imaging of Evaporating Fuel Droplets by Stereoscopic PIV  

Science Conference Proceedings (OSTI)

A gun-type burner is a widely used oil burner for industrial and domestic applications. The oil is pressure-atomized and mixed with air generating a recirculating, swirling flow. Because of the surrounding flame, fuel droplets evaporate, being difficult ... Keywords: 3D PIV, Stereoscopic PIV, droplet dynamics, spray combustion

V. Palero; Y. Ikeda

2002-08-01T23:59:59.000Z

330

Cell dynamics simulation of droplet and bridge formation within striped nano-capillaries  

E-Print Network (OSTI)

The kinetics of droplet and bridge formation within striped nano-capillaries is studied when the wetting film grows via interface-limited growth. The phenomenological time-dependent Ginzburg-Landau (TDGL)-type model with thermal noise is used and numerically solved using the cell dynamics method. The model is two-dimensional and consists of undersaturated vapor confined within a nano-capillary made of two infinitely wide flat substrates. The surface of the substrate is chemically heterogeneous with a single stripe of lyophilic domain that exerts long-range attractive potential to the vapor molecule. The dynamics of nucleation and subsequent growth of droplet and bridge can be simulated and visualized. In particular, the evolution of the morphology from droplet or bump to bridge is clearly identified. Crucial role played by the substrate potential on the morphology of bridge of nanoscopic size is clarified. Nearly temperature-independent evolution of capillary condensation is predicted when the interface-limited growth dominates. In addition, it is shown that the dynamics of capillary condensation follows the scenario of capillary condensation proposed by Everett and Haynes three decades ago.

Masao Iwamatsu

2007-08-13T23:59:59.000Z

331

Leidenfrost temperature increase for impacting droplets on carbon-nanofiber surfaces  

E-Print Network (OSTI)

Droplets impacting on a superheated surface can either exhibit a contact boiling regime, in which they make direct contact with the surface and boil violently, or a film boiling regime, in which they remain separated from the surface by their own vapor. The transition from the contact to the film boiling regime depends not only on the temperature of the surface and kinetic energy of the droplet, but also on the size of the structures fabricated on the surface. Here we experimentally show that surfaces covered with carbon-nanofibers delay the transition to film boiling to much higher temperature compared to smooth surfaces. We present physical arguments showing that, because of the small scale of the carbon fibers, they are cooled by the vapor flow just before the liquid impact, thus permitting contact boiling up to much higher temperatures than on smooth surfaces. We also show that, as long as the impact is in the film boiling regime, the spreading factor of impacting droplets follows the same $\\We^{3/10}$ sc...

Nair, Hrudya; Tran, Tuan; van Houselt, Arie; Prosperetti, Andrea; Lohse, Detlef; Sun, Chao

2013-01-01T23:59:59.000Z

332

Heat Transfer from Condensate Droplets Falling through an Immiscible Layer of Tributyl Phosphate  

Science Conference Proceedings (OSTI)

As part of a safety analysis of reactions in two-layer mixtures of nitric acid and tributyl phosphate (TBP), an experiment was conducted to study how steam condensate mixes with the TBP layer when steam passes over a TBP-nitric acid mixture. The experiments showed that the condensate does not form a separate layer on top of the TBP but instead percolates as droplets through the TBP layer. The temperature at the top surface of the TBP layer undergoes a step change increase when the initial condensate droplets reach the surface. Temperatures at the surface and within the TBP and aqueous layers subsequently approach a steady state distribution governed by laminar convection and radiation heat transfer from the vapor space above the two-layer mixture. The rate of temperature increase and the steady state temperature gradient are determined by a characteristic propagation velocity and a streamwise dispersion coefficient for heat transfer. The propagation velocity is the geometric mean of the thermal convection velocities for the organic and aqueous phases, and the dispersion coefficient equals 0.494 times the product of the superficial condensate droplet velocity and the diameter of the test vessel. The value of the dispersion coefficient agrees with the Joshi (1980) correlation for liquid phase backmixing in bubble columns. Transient perturbations occur in the TBP layer temperatures. A Fourier analysis shows that the dominant frequency of these perturbations equals the natural frequency given by the transient heat transfer solution.

Laurinat, James E.

2005-08-22T23:59:59.000Z

333

The polyomavirus BK agnoprotein co-localizes with lipid droplets  

SciTech Connect

Agnoprotein encoded by human polyomavirus BK (BKV) is a late cytoplasmic protein of 66 amino acids (aa) of unknown function. Immunofluorescence microscopy revealed a fine granular and a vesicular distribution in donut-like structures. Using BKV(Dunlop)-infected or agnoprotein-transfected cells, we investigated agnoprotein co-localization with subcellular structures. We found that agnoprotein co-localizes with lipid droplets (LD) in primary human renal tubular epithelial cells as well as in other cells supporting BKV replication in vitro (UTA, Vero cells). Using agnoprotein-enhanced green fluorescent protein (EGFP) fusion constructs, we demonstrate that agnoprotein aa 20-42 are required for targeting LD, whereas aa 1-20 or aa 42-66 were not. Agnoprotein aa 22-40 are predicted to form an amphipathic helix, and mutations A25D and F39E, disrupting its hydrophobic domain, prevented LD targeting. However, changing the phosphorylation site serine-11 to alanine or aspartic acid did not alter LD co-localization. Our findings provide new clues to unravel agnoprotein function.

Unterstab, Gunhild; Gosert, Rainer; Leuenberger, David [Transplantation Virology, Institute for Medical Microbiology, Department of Biomedicine, University of Basel, CH-4003 Basel (Switzerland); Lorentz, Pascal [Bio-Optics Facility, Department of Biomedicine, University of Basel, Basel (Switzerland); Rinaldo, Christine H. [Department of Microbiology and Infection Control, University Hospital of North Norway, Tromso (Norway); Hirsch, Hans H., E-mail: hans.hirsch@unibas.c [Transplantation Virology, Institute for Medical Microbiology, Department of Biomedicine, University of Basel, CH-4003 Basel (Switzerland); Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel (Switzerland)

2010-04-10T23:59:59.000Z

334

Droplets Behavior of Hollow-Cone Spray in a Non-Condensable Environment  

SciTech Connect

The characteristics of droplets in a water hollow-cone spray from nozzles 1.1 mm and 3.6 mm in diameter in an air environment have been investigated experimentally. The dual phase Doppler anemometry (PDA) system was used to measure the size and two velocity components of individual spherical particles. The liquid spray geometry, including spray breakup length and spray angle were also obtained experimentally. The mechanism and the influence of these parameters on a hollow cone spray flow were described. (authors)

Minoru Takahashi; Shin-ichi Kitagawa [Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152 (Japan); Suizheng Qiu [Xi' an Jiaotong University, No.28, Xianning West Road, Xi' an, Shaanxi, 710049 (China)

2002-07-01T23:59:59.000Z

335

Characteristics of the Raindrop Size Distribution and Drop Shape Relation in Typhoon Systems in the Western Pacific from the 2D Video Disdrometer and NCU C-Band Polarimetric Radar  

Science Conference Proceedings (OSTI)

The drop size distribution (DSD) and drop shape relation (DSR) characteristics that were observed by a ground-based 2D video disdrometer and retrieved from a C-band polarimetric radar in the typhoon systems during landfall in the western Pacific, ...

Wei-Yu Chang; Tai-Chi Chen Wang; Pay-Liam Lin

2009-10-01T23:59:59.000Z

336

Estimating the Accuracy of Polarimetric Radar–Based Retrievals of Drop-Size Distribution Parameters and Rain Rate: An Application of Error Variance Separation Using Radar-Derived Spatial Correlations  

Science Conference Proceedings (OSTI)

The accuracy of retrieving the two drop size distribution (DSD) parameters, median volume diameter (D0), and normalized intercept parameter (NW), as well as rain rate (R), from polarimetric C-band radar data obtained during a cool-season, long-...

M. Thurai; V. N. Bringi; L. D. Carey; P. Gatlin; E. Schultz; W. A. Petersen

2012-06-01T23:59:59.000Z

337

A Methodology for Estimating the Parameters of a Gamma Raindrop Size Distribution Model from Polarimetric Radar Data: Application to a Squall-Line Event from the TRMM/Brazil Campaign  

Science Conference Proceedings (OSTI)

A methodology is proposed for estimating the parameters of a gamma raindrop size distribution model from radar measurements of Zh, Zdr, and Kdp at S band. Previously developed algorithms by Gorgucci et al. are extended to cover low rain-rate ...

V. N. Bringi; Gwo-Jong Huang; V. Chandrasekar; E. Gorgucci

2002-05-01T23:59:59.000Z

338

Microfluidic emulsion characterization for the development of armored droplet arrays  

E-Print Network (OSTI)

An experimental study was performed to determine the best method for using a flow-focusing device to produce monodisperse water droplets in a polymer flow with sufficient spacing to polymerize a protective shell around the ...

Maltas, Stephen K

2006-01-01T23:59:59.000Z

339

Effect of Electric Charge on Collisions between Cloud Droplets  

Science Conference Proceedings (OSTI)

A simple model is presented for the calculation of the effect of electric charges on the collision and coalescence of cloud droplets, a topic that is of importance for coalescence-induced natural rainfall and for the possible effectiveness of ...

Neville H. Fletcher

2013-02-01T23:59:59.000Z

340

Droplet minimizers for the Cahn Hilliard free energy functional  

E-Print Network (OSTI)

We prove theorem characterizing the minimizers in a model for condensation based on the Cahn Hilliard free energy functional. In particular, we exactly determine the critical density for droplet formation.

E. A. Carlen; M. C. Carvalho; R. Esposito; J. L. Lebowitz; R. Marra

2005-05-11T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

On the Relationship between Sulfate and Cloud Droplet Number Concentrations  

Science Conference Proceedings (OSTI)

Comparisons are drawn between the aerosol cloud microphysical theory implicit in the modeling of Kaufman et al. and the cloud droplet and cloud water sulfate concentrations of Leaitch et al. for the purpose of helping to understand the effect of ...

W. R. Leaitch; G. A. Isaac

1994-01-01T23:59:59.000Z

342

Analysis of Tools Used to Quantify Droplet Clustering in Clouds  

Science Conference Proceedings (OSTI)

The spacing of cloud droplets observed along an approximately horizontal line through a cloud may be analyzed using a variety of techniques to reveal structure on small scales, sometimes called clustering, if such structure exists. A number of ...

Brad Baker; R. Paul Lawson

2010-10-01T23:59:59.000Z

343

On the Median Volume Diameter Approximation for Droplet Collision Efficiency  

Science Conference Proceedings (OSTI)

In this note, we examine a shortcut for calculating the overall collision efficiency of a droplet spectrum, known as the “median volume diameter” (mvd) approximation. By calculating the overall collision efficiency of a circular cylinder for a ...

Karen J. Finstad; Edward P. Lozowski; Lasse Makkonen

1988-12-01T23:59:59.000Z

344

Surface characterization of polymethylmetacrylate bombarded by charged water droplets  

Science Conference Proceedings (OSTI)

The electrospray droplet impact (EDI), in which the charged electrospray water droplets are introduced in vacuum, accelerated, and allowed to impact the sample, is applied to polymethylmetacrylate (PMMA). The secondary ions generated were measured by an orthogonal time-of-flight mass spectrometer. In EDI mass spectra for PMMA, fragment ions originating from PMMA could not be detected. This is due to the fact that the proton affinities of fragments formed from PMMA are smaller than those from acetic acid contained in the charged droplet. The x-ray photoelectron spectroscopy spectra of PMMA irradiated by water droplets did not change with prolonged cluster irradiation, i.e., EDI is capable of shallow surface etching for PMMA with a little damage of the sample underneath the surface.

Hiraoka, Kenzo; Takaishi, Riou; Asakawa, Daiki; Sakai, Yuji; Iijima, Yoshitoki [Clean Energy Research Center, University of Yamanashi, Takeda-4, Kofu 400-8511 (Japan); Japan Science and Technology Agency, Naka-ku, Hamamatsu 432-8561 (Japan); Electron Optics Sales Division, JEOL Ltd., 2-8-3 Akebono, Tachikawa, Tokyo 190-0012 (Japan)

2009-07-15T23:59:59.000Z

345

An Analysis and Comparison of Five Water Droplet Measuring Instruments  

Science Conference Proceedings (OSTI)

Five different instruments have been used routinely by the University of Wyoming for aircraft measurements of water droplets. A study has been conducted in which the measurement accuracies of these instruments are analyzed and evaluated. This ...

Darrel Baumgardner

1983-05-01T23:59:59.000Z

346

Effects of Image Charges on the Scavenging of Aerosol Particles by Cloud Droplets and on Droplet Charging and Possible Ice Nucleation Processes  

Science Conference Proceedings (OSTI)

Previous calculations of the rate at which falling droplets in clouds collide with aerosols have led to the conclusion that except in thunderclouds any electrical charges on the aerosols or droplets have little effect on the collision rate. ...

B. A. Tinsley; R. P. Rohrbaugh; M. Hei; K. V. Beard

2000-07-01T23:59:59.000Z

347

Preferential Concentration of Cloud Droplets by Turbulence: Effects on the Early Evolution of Cumulus Cloud Droplet Spectra  

Science Conference Proceedings (OSTI)

A mechanism is presented, based on the inherent turbulent nature of cumulus clouds, for the broadening of cloud droplet spectra during condensational growth. This mechanism operates independent of entrainment and, therefore, can operate in ...

Raymond A. Shaw; Walter C. Reade; Lance R. Collins; Johannes Verlinde

1998-06-01T23:59:59.000Z

348

Distance-Scaled Water Concentrations versus Mass-Median Drop Size, Temperature, and Altitude in Supercooled Clouds  

Science Conference Proceedings (OSTI)

About 28 000 nautical miles (n mi) of select in-flight measurements of liquid water content (LWC), droplet sizes, temperature, and other variables in supercooled clouds from a variety of research projects over portions of North America, Europe, ...

Richard K. Jeck

2008-07-01T23:59:59.000Z

349

NCNR Magnetic Cluster Sizes in Recording Disks  

Science Conference Proceedings (OSTI)

... Presently, cluster sizes are believed to be about 10 nano meters to 15 nano meters, but accurate knowledge of the size distribution and even the ...

350

Comparison of the Vertical Velocity Used to Calculate the Cloud Droplet Number Concentration in a Cloud Resolving and a Global Climate Model  

NLE Websites -- All DOE Office Websites (Extended Search)

Comparison of the Vertical Velocity Comparison of the Vertical Velocity used to Calculate the Cloud Droplet Number Concentration in a Cloud-Resolving and a Global Climate Model H. Guo, J. E. Penner, M. Herzog, and X. Liu Department of Atmospheric, Oceanic and Space Sciences University of Michigan Ann Arbor, Michigan Introduction Anthropogenic aerosols are effective cloud condensation nuclei (CCN). The availability of CCN affects the initial cloud droplet number concentration (CDNC) and droplet size; therefore, cloud optical properties (the so-called first aerosol indirect effect). However, the estimate of CDNC from a mechanistic treatment shows significant differences from the empirical schemes mainly due to the large bias of the large-scale vertical velocity (w) (Ghan et al. 1993, 1995; Boucher and Lohmann 1995;

351

Ice Cloud Particle Size Distributions and Pressure-Dependent Terminal Velocities from In Situ Observations at Temperatures from 0 to ?86 C  

Science Conference Proceedings (OSTI)

The primary goal of this study is to derive ice particle terminal velocities from micron to cm sizes and for atmospheric pressures covering the range 200–1000 hPa from data spanning a wide range of locations, temperatures, and altitudes and to ...

Andrew J. Heymsfield; Carl Schmitt; Aaron Bansemer

352

Size dependent motion of nanodroplets on chemical steps  

E-Print Network (OSTI)

Nanodroplets on chemically structured substrates move under the action of disjoining pressure induced forces. A detailed analysis of them shows that even in the absence of long-ranged lateral variations of the effective interface potential, already the fact, that due their small size nano-droplets do not sample the disjoining pressure at all distances from the substrate, can lead to droplet motion towards the less wettable part of the substrate, i.e., in the direction opposite to the one expected on the basis of macroscopic wettability considerations.

A. Moosavi; M. Rauscher; S. Dietrich

2008-05-05T23:59:59.000Z

353

MEASUREMENTS AND COMPUTATIONS OF FUEL DROPLET TRANSPORT IN TURBULENT FLOWS  

SciTech Connect

The objective of this project is to study the dynamics of fuel droplets in turbulent water flows. The results are essential for development of models capable of predicting the dispersion of slightly light/heavy droplets in isotropic turbulence. Since we presently do not have any experimental data on turbulent diffusion of droplets, existing mixing models have no physical foundations. Such fundamental knowledge is essential for understanding/modeling the environmental problems associated with water-fuel mixing, and/or industrial processes involving mixing of immiscible fluids. The project has had experimental and numerical components: 1. The experimental part of the project has had two components. The first involves measurements of the lift and drag forces acting on a droplet being entrained by a vortex. The experiments and data analysis associated with this phase are still in progress, and the facility, constructed specifically for this project is described in Section 3. In the second and main part, measurements of fuel droplet dispersion rates have been performed in a special facility with controlled isotropic turbulence. As discussed in detail in Section 2, quantifying and modeling the of droplet dispersion rate requires measurements of their three dimensional trajectories in turbulent flows. To obtain the required data, we have introduced a new technique - high-speed, digital Holographic Particle Image Velocimetry (HPIV). The technique, experimental setup and results are presented in Section 2. Further information is available in Gopalan et al. (2005, 2006). 2. The objectives of the numerical part are: (1) to develop a computational code that combines DNS of isotropic turbulence with Lagrangian tracking of particles based on integration of a dynamical equation of motion that accounts for pressure, added mass, lift and drag forces, (2) to perform extensive computations of both buoyant (bubbles) and slightly buoyant (droplets) particles in turbulence conditions relevant to the experiments, and (3) to explore whether the corresponding predictions can explain the experimentally-observed behavior of the rise and dispersion of oil droplets in isotropic turbulence. A brief summary of results is presented in Section 4.

Joseph Katz and Omar Knio

2007-01-10T23:59:59.000Z

354

Spontaneous motion of a droplet coupled with a chemical wave  

E-Print Network (OSTI)

We propose a novel framework for the spontaneous motion of a droplet coupled with internal dynamic patterns generated in a reaction-diffusion system. The spatio-temporal order of the chemical reaction gives rise to inhomogeneous surface tension and results in self-propulsion driven by the surrounding flow due to the Marangoni effect. Numerical calculations of internal patterns together with theoretical results of the flow fields at low Reynolds number well reproduces the experimental results obtained using a droplet of Belousov-Zhabotinsky (BZ) reaction medium.

Hiroyuki Kitahata; Natsuhiko Yoshinaga; Ken H. Nagai; Yutaka Sumino

2010-12-13T23:59:59.000Z

355

The Effects of van der Waals Attractions on Cloud Droplet Growth by Coalescence  

Science Conference Proceedings (OSTI)

The inclusion of van der Waals attractions in the interaction between cloud droplets has been recently shown to significantly increase the collision efficiencies of the smaller droplets. In the current work, these larger values for the collision ...

Jan R. Rogers; Robert H. Davis

1990-05-01T23:59:59.000Z

356

Rain Enhancement and Fog Elimination by Seeding with Charged Droplets. Part I: Theory and Numerical Simulations  

Science Conference Proceedings (OSTI)

A new method of droplet collision acceleration, with the purpose of rain enhancement and fog elimination, is proposed. According to the method, some fraction of the droplets is taken from clouds (or fog) themselves, charged, and then injected ...

A. Khain; V. Arkhipov; M. Pinsky; Y. Feldman; Ya Ryabov

2004-10-01T23:59:59.000Z

357

Effect of Air Bubbles on Absorption of Solar Radiation by Water Droplets  

Science Conference Proceedings (OSTI)

It was suggested that absorption by a weakly absorbing droplet may be increased substantially by the presence of air bubbles within a droplet. The authors use an exact solution of the scattering of electromagnetic waves by a spherical particle ...

Petr Chýlek; Gorden Videen; Dat Ngo

1998-02-01T23:59:59.000Z

358

Parameterization of Droplet Terminal Velocity and Extinction Coefficient in Fog Models  

Science Conference Proceedings (OSTI)

Fog droplet spectra data were obtained in several advection fogs at the AFGL Weather Test Facility at Otis Air National Guard Base, Massachusetts, using two PMS forward-scatter spectrometer probes (FSSP-100). Approximately 90 h of droplet data ...

Bruce A. Kunkel

1984-01-01T23:59:59.000Z

359

Deposition of micron liquid droplets on wall in impinging turbulent air jet  

E-Print Network (OSTI)

The fluid mechanics of the deposition of micron liquid (olive oil) droplets on a glass wall in an impinging turbulent air jet is studied experimentally. The spatial patterns of droplets deposited on a wall are measured by ...

Liu, Tianshu

360

Droplet Breakup in Flow Past an Obstacle: A Capillary Instability Due to Permeability Variations  

E-Print Network (OSTI)

In multiphase flow in confined geometries an elementary event concerns the interaction of a droplet with an obstacle. As a model of this configuration we study the collision of a droplet with a circular post that spans a ...

Protière, S.

Note: This page contains sample records for the topic "droplet size distribution" 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

Temperature Dependence of Evaporation Coefficient for Water Measured in Droplets in Nitrogen under Atmospheric Pressure  

Science Conference Proceedings (OSTI)

The evaporation and the thermal accommodation coefficients for water in nitrogen were investigated by means of the analysis of evaporation of pure water droplet as a function of temperature. The droplet was levitated in an electrodynamic trap ...

D. Jakubczyk; M. Zientara; K. Kolwas; M. Kolwas

2007-03-01T23:59:59.000Z

362

Net Metering Policy Development and Distributed Solar Generation in Minnesota: Overview of Trends in Nationwide Policy Development and Implications of Increasing the Eligible System Size Cap  

NLE Websites -- All DOE Office Websites (Extended Search)

0 0 December 2009 Net Metering Policy Development in Minnesota: Overview of Trends in Nationwide Policy Development and Implications of Increasing the Eligible System Size Cap Elizabeth Doris, Sarah Busche, and Stephen Hockett National Renewable Energy Laboratory 1617 Cole Boulevard, Golden, Colorado 80401-3393 303-275-3000 * www.nrel.gov NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Operated by the Alliance for Sustainable Energy, LLC Contract No. DE-AC36-08-GO28308 Technical Report NREL/TP-6A2-46670 December 2009 Net Metering Policy Development in Minnesota: Overview of Trends in Nationwide Policy Development and Implications of Increasing the Eligible System Size Cap

363

THE LIFETIME OF AEROSOL DROPLETS IN AMBIENT AIR: CONSIDERATION OF THE EFFECTS OF SURFACTANTS AND CHEMICAL REACTIONS  

E-Print Network (OSTI)

of various urban sulfate aerosol production mechanisms.radius of an evaporating aerosol droplet in which oxidationEnvironment THE LIFETIME OF AEROSOL DROPLETS IN AMBIENT AIR:

Toossi, R.

2013-01-01T23:59:59.000Z

364

Crack Formation in the Presence of an Electric Field in Droplets of Laponite Gel  

E-Print Network (OSTI)

When a colloidal gel dries through evaporation, cracks are usually formed, which often reveal underlying processes at work during desiccation. Desiccating colloid droplets of few hundred $\\mu l$ size show interesting effects of pattern formation and cracking which makes this an active subject of current research. Since aqueous gels of clay are known to be strongly affected by an electric field, one may expect crack patterns to exhibit a field effect. In the present study we allow droplets of laponite gel to dry under a radial electric field. This gives rise to highly reproducible patterns of cracks, which depend on the strength, direction and time of exposure to the electric field. For a continuously applied DC voltage, cracks always appear on dissipation of a certain constant amount of energy. If the field is switched off before cracks appear, the observed results are shown to obey a number of empirical scaling relations, which enable us to predict the time of appearance and the number of cracks under specified conditions.

Tajkera Khatun; Tapati Dutta; Sujata Tarafdar

2013-08-14T23:59:59.000Z

365

Fast high-performance algorithms for multi-pin droplet routing in digital microfluidic biochips  

Science Conference Proceedings (OSTI)

The use of microfluidics for building biochips is an emerging research area. A key challenge in this area is the droplet routing problem in the design of digital microfluidic biochips. It involves the scheduling of movement of a number of droplets in ... Keywords: algorithms, digital microfluidic biochips, droplet routing, microfluidics

Pranab Roy; Hafizur Rahaman; Parthasarathi Dasgupta

2011-05-01T23:59:59.000Z

366

Size Effects  

Science Conference Proceedings (OSTI)

Mar 5, 2013 ... An Explanation of the Power-Exponent in the Size Effect on Strength in ... in terms of the Taylor-type resistance in the dislocation network in the specimen. ... hysteresis and loss in pseudoelasticity with decrease in sample size.

367

Zones of Increased and Decreased Droplet Concentration in Stratiform Clouds  

Science Conference Proceedings (OSTI)

The finescale, spatial inhomogeneity of cloud-droplet concentration in stratiform clouds is studied using FSSP-100 data with 10-m or better resolution from 1700 km of cloud penetrations between +5° and ?20°C. The data are analyzed in terms of the ...

A. V. Korolev; I. P. Mazin

1993-04-01T23:59:59.000Z

368

Droplet Spectra Observed in Marine Stratus Cloud Layers  

Science Conference Proceedings (OSTI)

Airborne measurements of the water droplet spectra n(r) (r is radius) (0.23 ? r ? 150 ?m) were made at about 14 levels in stratus layers during May and August 1981, 130 km SW of San Diego. All May days were found to be associated with air masses ...

V. Ray Noonkester

1984-03-01T23:59:59.000Z

369

Jumping-Droplet-Enhanced Condensation on Scalable Superhydrophobic Nanostructured Surfaces  

Science Conference Proceedings (OSTI)

When droplets coalesce on a superhydrophobic nanostructured surface, the resulting droplet can jump from the surface due to the release of excess surface energy. If designed properly, these superhydrophobic nanostructured surfaces can not only allow for easy droplet removal at micrometric length scales during condensation but also promise to enhance heat transfer performance. However, the rationale for the design of an ideal nanostructured surface as well as heat transfer experiments demonstrating the advantage of this jumping behavior are lacking. Here, we show that silanized copper oxide surfaces created via a simple fabrication method can achieve highly efficient jumping-droplet condensation heat transfer. We experimentally demonstrated a 25% higher overall heat flux and 30% higher condensation heat transfer coefficient compared to state-of-the-art hydrophobic condensing surfaces at low supersaturations (heat transfer enhancement but also promises a low cost and scalable approach to increase efficiency for applications such as atmospheric water harvesting and dehumidification. Furthermore, the results offer insights and an avenue to achieve high flux superhydrophobic condensation.

Miljkovic, N; Enright, R; Nam, Y; Lopez, K; Dou, N; Sack, J; Wang, E

2012-01-01T23:59:59.000Z

370

Supercritical Burning of Liquid Oxygen (LOX) Droplet with Detailed Chemistry  

E-Print Network (OSTI)

Supercritical Burning of Liquid Oxygen (LOX) Droplet with Detailed Chemistry J. DAOU,* P with diameter less than I pm vaporize before burning. A quasi-steady-like diffusion flame is then established is considered; temperature and pressure in the combustion chamber have a weak influence on the burning time

Heil, Matthias

371

Pore size estimation  

Science Conference Proceedings (OSTI)

A novel method for characterization of any porous structure is presented. The principle of the method is simple scanning a plane surface of a cellular material and consequent digital image analysis of the scan. Eleven samples of bread baked from dough ... Keywords: foams, image analysis, modelling the structure, plane cut visualization, pore size distribution, voronoi tessellation

Tomas Matousek; Petr Ponizil; Filip Kremen; Iva Buresova; Petra Dvorakova

2011-07-01T23:59:59.000Z

372

Analysis of transport mechanisms in dense fuel droplet sprays. Final report  

DOE Green Energy (OSTI)

This report deals with numerical analyses of fluid mechanics, heat transfer, mass transfer and particle dynamics of interacting spheres and vaporizing droplets in a linear array or on a 1-D trajectory. Available finite element software has been modified and extended to solve several case studies including closely spaced monodisperse spheres with or without blowing; closely spaced vaporizing fuel droplets; and dynamically interacting vaporizing fuel droplets on a 1-D trajectory. Axisymmetric laminar flow has been assumed for three statically or dynamically interacting spherical solids and vaporizing droplets. Emphasis in this work is evaluating the effects of key system parameters, such as free stream Reynolds number, interparticle spacings, liquid/gas-phase viscosity ratio and variable fluid properties, on interfacial transfer processes and on the particle Nusselt number, vaporization rate and drag coefficient. Computer-generated correlations between integral quantities and system parameters were postulated for blowing spheres and vaporizing droplets. In addition to initial Reynolds number and droplet spacings, variable fluid properties, liquid-phase heating and internal droplet circulation have strong effect on the dynamic behavior of multi-droplet systems. While the lead droplet is most significantly affected by all key parameters, the second and third droplet causes distinct interaction effects which are largely dependent on initial droplet spacings. Applications include spherical-structure/fluid-flow interactions, as well as interacting vaporizing droplets in different sprays related to propulsion systems, irrigation, spray coating, etc. Focusing on fuel droplet sprays, results of the dynamic multi-droplet study can assist in better atomizers and combustion chamber designs which may lead to improved combustion efficiencies, smaller/lighter systems, and reduced pollutant emissions.

Kleinstreuer, C.

1991-05-01T23:59:59.000Z

373

Study of enhanced droplet cooling across grid spacer in LOCA reflood of PWR by LDA measurement  

SciTech Connect

An experimental investigation of droplet-vapor mist flow across a test grid spacer was conducted. The study sought to simulate the grid spacer enhanced droplet cooling under reflooding conditions in the loss-of-coolant accident (LOCA) of a pressurized water reactor (PWR). The study also provides a fundamentally improved understanding of the basic mechanisms concerning droplet dynamics and droplet-vapor mist flow heat transfer. An understanding of water droplet dynamics is necessary for explaining the sharp drop in cladding temperature observed immediately downstream of the grid spacer. A test channel that simulates the PWR reactor rod bundle was built to conduct both temperature measurements of the rod cladding and vapor flow, and droplet dynamics measurements before and after the grid spacer. The large droplets ( >1mm), which thermally are relatively inactive, are intercepted by the grid spacer and broken down into smaller, thermally more active, droplets (<200 /sup +/m). This investigation discusses droplet dynamics and heat transfer mechanisms across the grid spacer. It also provides a detailed discussion of the grid spacer's quenching behavior, the cooling downstream, and the droplet enhancement cooling, combined with the results of the full-length rod-bundle test.

Sheen, H.J.

1987-01-01T23:59:59.000Z

374

Evaporation-Induced Buckling and Fission of Microscale Droplet Interface Bilayers  

Science Conference Proceedings (OSTI)

Droplet interface bilayers (DIBs) are a robust platform for studying synthetic cellular membranes; however, to date no DIBs have been produced at cellular length scales. Here, we create microscale droplet interface bilayers ( DIBs) at the interface between aqueous femtoliter-volume droplets within an oil-filled microfluidic channel. The uniquely large area-to-volume ratio of the droplets results in strong evaporation effects, causing the system to transition through three distinct regimes. First, the two adjacent droplets shrink into the shape of a single spherical droplet, where an augmented lipid bilayer partitions two hemi-spherical volumes. In the second regime, the combined effects of the shrinking monolayers and growing bilayer force the confined bilayer to buckle to conserve its mass. Finally, at a bending moment corresponding to a critical shear stress, the buckling bilayer fissions a vesicle to regulate its shape and stress. The DIBs produced here enable evaporation-induced bilayer dynamics reminiscent of endo- and exocytosis in cells.

Boreyko, Jonathan B [ORNL; Mruetusatorn, Prachya [ORNL; Sarles, Stephen A [ORNL; Retterer, Scott T [ORNL; Collier, Pat [ORNL

2013-01-01T23:59:59.000Z

375

www.elsevier.com/locate/ijhmt In-flight thermal control of molten metal droplet streams  

E-Print Network (OSTI)

Precision droplet manufacturing (PDM) is a process that builds complex 3D parts one nano-liter molten metal droplet at a time from a CAD file without the need for tooling. One method to control the droplet temperature when it arrives at the target is to heat the droplets in-flight. This note describes such a heater that uses helium and nitrogen as the convective heat transfer medium. Heating rates up to 11,000 °C/s are attained. The effect of droplet spacing on the heat transfer coefficient is experimentally detailed and a nascent-turbulent effect is observed to bring the heating rate for nitrogen close to that for helium. In addition, the experimental values are consistent with those from multi-droplet numerical simulations reported in the literature.

B. Matthew Michaelis; Derek Dunn-rankin; Robert F. Smith; James E. Bobrow

2007-01-01T23:59:59.000Z

376

Two-dimensional fluid droplet arrays generated using a single nozzle  

DOE Patents (OSTI)

Amplitudes of drive pulses received by a horizontally-placed dropper determine the horizontal displacements of droplets relative to an ejection aperture of the dropper. The drive pulses are varied such that the dropper generates a two-dimensional array of vertically-falling droplets. Vertical and horizontal interdroplet spacings may be varied in real time. Applications include droplet analysis experiments such as Millikan fractional charge searches and aerosol characterization, as well as material deposition applications.

Lee, Eric R. (Redwood City, CA); Perl, Martin L. (Palo Alto, CA)

1999-11-02T23:59:59.000Z

377

Chemical Amplification (or Dampening) of the Twomey Effect: Conditions Derived from Droplet Activation Theory  

Science Conference Proceedings (OSTI)

Cloud droplet number concentrations are controlled by both meteorological and microphysical factors. Microphysical factors include aerosol number concentration and composition. This paper examines the importance of microphysical phenomena ...

T. A. Rissman; A. Nenes; J. H. Seinfeld

2004-04-01T23:59:59.000Z

378

Thermo-fluid Dynamics of Flash Atomizing Sprays and Single Droplet Impacts.  

E-Print Network (OSTI)

??Spray atomization and droplet dynamics are research topics that have existed for many decades. Their prevalence in manufacturing, energy generation and other practical applications is… (more)

Vu, Henry

2010-01-01T23:59:59.000Z

379

Vibration Induced Droplet Generation from a Liquid Layer for Evaporative Cooling in a Heat Transfer Cell .  

E-Print Network (OSTI)

??During this investigation, vibration induced droplet generation from a liquid layer was examined as a means for achieving high heat flux evaporative cooling. Experiments were… (more)

Pyrtle, Frank, III

2005-01-01T23:59:59.000Z

380

Interaction of the burning spherical droplets in oxygen-enriched turbulent environment  

SciTech Connect

Three-dimensional numerical studies on the interaction of vaporizing and burning droplets were conducted to understand the burning characteristics of multiple droplets in a turbulent environment. The burning droplets characteristics, such as lifetime, surface temperature, vaporization, reaction, and burning rate were examined for various oxygen mole-fractions and geometrical arrangements of droplets. Results from a single droplet combustion test were first verified and validated against existing experimental data. Results indicate that turbulent intensity has a moderate effect on droplet burning rate, but not as prominent an effect as the oxygen mole-fraction. At high oxygen mole-fractions, droplet lifetime was short due to enhanced burning. It is shown that evaporation processes of multiple droplets are notably affected by the inter-space distance between droplets both in streamwise and spanwise directions. The burning rate as a function of oxygen mole-fraction and inter-space distance is determined and can be used as a guideline for future studies on spray combustion. (author)

Cho, Chong Pyo [Automobile Energy and Environment Research Center, Korea Institute of Energy Research, 71-2 Jangdong, Yuseonggu, Daejeon, 305-343 (Korea); Kim, Ho Young; Yoon, Sam S. [Department of Mechanical Engineering, Korea University, Anamdong, 5-Ga, Sungbukgu, Seoul, 136-701 (Korea)

2009-01-15T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Calibration of Knollenberg FSSP Light-Scattering Counters for Measurement of Cloud Droplets  

Science Conference Proceedings (OSTI)

Measurement of cloud drop size distributions with the Knollenberg model FSSP-100 light-scattering counter can lead to artificial bumps or knees in the distributions at 0.6 ?m and sometimes 2–4 ?m radius if the manufacturer-supplied calibration ...

R. G. Pinnick; D. M. Garvey; L. D. Duncan

1981-09-01T23:59:59.000Z

382

Effect of an electric field on a Leidenfrost droplet  

E-Print Network (OSTI)

We experimentally investigate the effect of an electric field applied between a Leidenfrost droplet and the heated substrate on which it is levitating. We quantify the electro-Leidenfrost effect by imaging the interference fringes between the liquid-vapour and vapour-substrate interfaces. The increase of the voltage induces a decrease of the vapour layer thickness. Above a certain critical voltage the Leidenfrost effect is suppressed and the drop starts boiling. Our study characterizes this way to control and/or to avoid the Leidenfrost effect that is undesirable in many domains such as metallurgy or nuclear reactor safety.

Franck Celestini; G. Kirstetter

2012-03-21T23:59:59.000Z

383

Light Scattering Characteristics and Size Distribution of ...  

Science Conference Proceedings (OSTI)

... Ian Thomas at CESARE. REFERENCES ... [19] Mulholland, GW, Hartman, AW, Hembree, GG, Marx, E., and Lettieri, T. R., "Development of a one ...

2003-12-16T23:59:59.000Z

384

Modelin combustion of multicomponent fuel droplets: formulation and application to transportation fuels  

E-Print Network (OSTI)

The quasi-steady, spherically symmetric combustion of multicomponent isolated fuel droplets has been modeled using modified Shvab-Zeldovich variable mechanism. Newly developed modified Shvab-Zeldovich equations have been used to describe the gas phase reactions. Vapor-liquid equilibrium model has been applied to describe the phase change at the droplet surface. Constant gas phase specific heats are assumed. The liquid phase is assumed to be of uniform composition and temperature. Radiative heat transfer between the droplet and surroundings is neglected. The results of evaporation of gasoline with discrete composition of hydrocarbons have been presented. The evaporation rates seem to follow the pattern of volatility differentials. The evaporation rate constant was obtained as 0.344mm2/sec which compared well with the unsteady results of Reitz et al. The total evaporation time of the droplet at an ambience of 1000K was estimated to be around 0.63 seconds. Next, the results of evaporation of representative diesel fuels have been compared with previously reported experimental data. The previous experiments showed sufficient liquid phase diffusional resistance in the droplet. Numerical results are consistent with the qualitative behavior of the experiments. The quantitative deviation during the vaporization process can be attributed to the diffusion time inside the droplet which is unaccounted for in the model. Transient evaporation results have also been presented for the representative diesel droplets. The droplet temperature profile indicates that the droplet temperature does not reach an instantaneous steady state as in the case of single-component evaporation. To perform similar combustion calculations for multicomponent fuel droplets, no simple model existed prior to this work. Accordingly, a new simplified approximate mechanism for multicomponent combustion of fuel droplets has been developed and validated against several independent data sets. The new mechanism is simple enough to be used for computational studies of multicomponent droplets. The new modified Shvab-Zeldovich mechanism for multicomponent droplet combustion has been used to model the combustion characteristics of a binary alcohol-alkane droplet and validated against experimental data. Burn rate for the binary droplet of octanol-undecane was estimated to be 1.17mm2/sec in good concurrence with the experimental value of 0.952mm2/sec obtained by Law and Law. The model has then been used to evaluate the combustion characteristics of diesel fuels assuming only gas phase reactions. Flame sheet approximation has been invoked in the formulation of the model.

Vittilapuram Subramanian, Kannan

2004-12-01T23:59:59.000Z

385

Comparison of iso-octane burning rates between single-phase and two-phase combustion for small droplets  

Science Conference Proceedings (OSTI)

Two-phase combustion is a widespread mechanism of energy conversion that is of practical importance in gas turbines, diesel and spark ignition engines, furnaces, and hazardous environments. However, the exploration of important parameters in combustion systems of practical application is difficult, due to the multiplicity of dependent variables. In the present work, combustion rates of well-defined droplet suspensions of iso-octane have been measured using techniques employed for gaseous combustion. This required a full characterization of the aerosols produced in the combustion apparatus, which determined that the maximum droplet size produced was around 30 {mu}m. Comparisons of two-phase with single-phase laminar mixtures suggest that there were negligible differences in the burning velocity of an aerosol and a gaseous mixture at the same overall equivalence ratio and similar conditions for iso-octane. At high stretch rates, flames remained smooth and droplet enhancement was negligible. However, at lower rates of stretch, both gaseous and aerosol flames became unstable and cellular, and this cellularity, in some cases, increased the burning rate. The values of Markstein length measured for aerosol flames had trends similar to those for gaseous-phase mixtures (Markstein length decreased with equivalence ratio), but were lower than in gaseous combustion. The values of Markstein length in aerosol flames also decreased with liquid equivalence ratio and/or Sauter mean diameter. All this indicates a higher tendency to instabilities in aerosol flames compared to gaseous combustion. A qualitative explanation for the lower values of Markstein length in aerosol combustion is given. It is suggested in the present work that aerosol flames became unstable, and hence had faster burning rates, under conditions that would not result in unstable gaseous flames. Comparisons, qualitative and in terms of dimensionless groups, of two-phase with single-phase turbulent combustion also suggest no enhancement. (author)

Lawes, M.; Lee, Y. [School of Mechanical Engineering, The University of Leeds (United Kingdom); Marquez, N. [Escuela de Ingenieria Mecanica, Universidad del Zulia, Maracaibo 4011 Apto. 526 (Venezuela)

2006-02-01T23:59:59.000Z

386

In-service Inspection Ultrasonic Testing of Reactor Pressure Vessel Welds for Assessing Flaw Density and Size Distribution per 10 CFR 50.61a, Alternate Fracture Toughness Requirements  

SciTech Connect

Pressurized thermal shock (PTS) events are system transients in a pressurized water reactor (PWR) in which there is a rapid operating temperature cool-down that results in cold vessel temperatures with or without repressurization of the vessel. The rapid cooling of the inside surface of the reactor pressure vessel (RPV) causes thermal stresses that can combine with stresses caused by high pressure. The aggregate effect of these stresses is an increase in the potential for fracture if a pre-existing flaw is present in a material susceptible to brittle failure. The ferritic, low alloy steel of the reactor vessel beltline adjacent to the core, where neutron radiation gradually embrittles the material over the lifetime of the plant, can be susceptible to brittle fracture. The PTS rule, described in the Code of Federal Regulations, Title 10, Section 50.61 (§50.61), “Fracture Toughness Requirements for Protection against Pressurized Thermal Shock Events,” adopted on July 23, 1985, establishes screening criteria to ensure that the potential for a reactor vessel to fail due to a PTS event is deemed to be acceptably low. The U.S. Nuclear Regulatory Commission (NRC) completed a research program that concluded that the risk of through-wall cracking due to a PTS event is much lower than previously estimated. The NRC subsequently developed a rule, §50.61a, published on January 4, 2010, entitled “Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events” (75 FR 13). Use of the new rule by licensees is optional. The §50.61a rule differs from §50.61 in that it requires licensees who choose to follow this alternate method to analyze the results from periodic volumetric examinations required by the ASME Code, Section XI, Rules for Inservice Inspection (ISI) of Nuclear Power Plants. These analyses are intended to determine if the actual flaw density and size distribution in the licensee’s reactor vessel beltline welds are bounded by the flaw density and size distribution values used in the PTS technical basis. Under a contract with the NRC, Pacific Northwest National Laboratory (PNNL) has been working on a program to assess the ability of current inservice inspection (ISI)-ultrasonic testing (UT) techniques, as qualified through ASME Code, Appendix VIII, Supplements 4 and 6, to detect small fabrication or inservice-induced flaws located in RPV welds and adjacent base materials. As part of this effort, the investigators have pursued an evaluation, based on the available information, of the capability of UT to provide flaw density/distribution inputs for making RPV weld assessments in accordance with §50.61a. This paper presents the results of an evaluation of data from the 1993 Browns Ferry Nuclear Plant, Unit 3, Spirit of Appendix VIII reactor vessel examination, a comparison of the flaw density/distribution from this data with the distribution in §50.61a, possible reasons for differences, and plans and recommendations for further work in this area.

Sullivan, Edmund J.; Anderson, Michael T.; Norris, Wallace

2012-09-17T23:59:59.000Z

387

Droplet evolution in expanding flow of warm dense matter  

E-Print Network (OSTI)

We propose a simple, self-consistent kinetic model for the evolution of a mixture of droplets and vapor expanding adiabatically in vacuum after rapid, almost isochoric heating. We study the evolution of the two-phase fluid at intermediate times between the molecular and the hydrodynamic scales, focusing on out-of-equilibrium and surface effects. We use the van der Waals equation of state as a test bed to implement our model and study the phenomenology of the upcoming second neutralized drift compression experiment (NDCX-II) at Lawrence Berkeley National Laboratory (LBNL) that uses ion beams for target heating.We find an approximate expression for the temperature difference between the droplets and the expanding gas and we check it with numerical calculations. The formula provides a useful criterion to distinguish the thermalized and nonthermalized regimes of expansion. In the thermalized case, the liquid fraction grows in a proportion that we estimate analytically, whereas, in case of too rapid expansion, a s...

Armijo, Julien; 10.1103/PhysRevE.83.051507

2011-01-01T23:59:59.000Z

388

High speed flow cytometer droplet formation system and method  

DOE Patents (OSTI)

A droplet forming flow cytometer system allows high speed processing without the need for high oscillator drive powers through the inclusion of an oscillator or piezoelectric crystal such as within the nozzle volume or otherwise unidirectionally coupled to the sheath fluid. The nozzle container continuously converges so as to amplify unidirectional oscillations which are transmitted as pressure waves through the nozzle volume to the nozzle exit so as to form droplets from the fluid jet. The oscillator is directionally isolated so as to avoid moving the entire nozzle container so as to create only pressure waves within the sheath fluid. A variation in substance concentration is achieved through a movable substance introduction port which is positioned within a convergence zone to vary the relative concentration of substance to sheath fluid while still maintaining optimal laminar flow conditions. This variation may be automatically controlled through a sensor and controller configuration. A replaceable tip design is also provided whereby the ceramic nozzle tip is positioned within an edge insert in the nozzle body so as to smoothly transition from nozzle body to nozzle tip. The nozzle tip is sealed against its outer surface to the nozzle body so it may be removable for cleaning or replacement.

Van den Engh, Ger (Seattle, WA)

2000-01-01T23:59:59.000Z

389

Cavitation within a dropletCavitation within a droplet G. L. Heijnen1,2, P. A. Quinto-Su2, X. Zhao2, C. D. Ohl1,2  

E-Print Network (OSTI)

. The droplet is illuminated from behind with a high power light emitting diode (Seoul Semiconductor, P7

Ohl, Claus-Dieter

390

Fatty Acid Chemistry at the Oil-Water Interface: Self-Propelled Oil Droplets  

E-Print Network (OSTI)

Fatty Acid Chemistry at the Oil-Water Interface: Self-Propelled Oil Droplets Martin M. Hanczyc transitions. Here we have explored the possibility that fatty acid systems also demonstrate movement. An oil solution. The oil droplets showed autonomous, sustained movement through the aqueous media. Internal

Ikegami, Takashi

391

Method of dispensing droplets to penetration-resistive mediums. [Patent application  

DOE Patents (OSTI)

Uniform, monosized microspheroids are produced in a gelation medium characterized by a high resistance to surface penetration by reducing the effect of impact on entry of the droplets into the medium by contacting the droplet with a stream of medium and by introducing the resulting stream into a gelation column.

Fowler, V.L.; Ryon, A.D.; Haas, P.A.

1982-06-10T23:59:59.000Z

392

profiles of optical Extinction Coefficients Calculated from Droplet Spectra Observed in Marine Stratus Cloud Layers  

Science Conference Proceedings (OSTI)

Airborne measurements of droplet spectra n(r) where r is droplet radius were made in stratus cloud layers over the ocean 130 km southwest of San Diego. Optical extinction coefficients ?e were calculated at selected wavelengths (?= 0.53, 3.75 and ...

V. Ray Noonkester

1985-06-01T23:59:59.000Z

393

Experimental Study of Collection Efficiencies between Submicron Aerosols and Cloud Droplets  

Science Conference Proceedings (OSTI)

Collection efficiency E experiments for aerosol particles scavenged by cloud droplets were carried out in the newly built Collision Ice Nucleation Chamber (CLINCH). Pure water droplets having radii between 12.8 and 20.0 ?m were allowed to fall ...

Luis Ladino; Olaf Stetzer; Bodo Hattendorf; Detlef Günther; Betty Croft; Ulrike Lohmann

2011-09-01T23:59:59.000Z

394

Experimental Studies of Droplet Evaporation Kinetics: Validation of Models for Binary and Ternary Aqueous Solutions  

Science Conference Proceedings (OSTI)

Experiments were conducted with an electrodynamic levitation system to study the kinetics of droplet evaporation under chemically rich conditions. Single solution droplets of known composition (HNO3/H2O or H2SO4/HNO3/H2O) were introduced into an ...

Huiwen Xue; Alfred M. Moyle; Nathan Magee; Jerry Y. Harrington; Dennis Lamb

2005-12-01T23:59:59.000Z

395

Detachment of Liquid-Water Droplets from Gas-Diffusion Layers  

SciTech Connect

A critical issue for optimal water management in proton-exchange-membrane fuel cells at lower temperatures is the removal of liquid water from the cell. This pathway is intimately linked with the phenomena of liquid-water droplet removal from surface of the gas-diffusion layer and into the flow channel. Thus, a good understanding of liquid-water transport and droplet growth and detachment from the gas-diffusion layer is critical. In this study, liquid-water droplet growth and detachment on the gas-diffusion layer surfaces are investigated experimentally to improve the understating of water transport through and removal from gas-diffusion layers. An experiment using a sliding-angle measurement is designed and used to quantify and directly measure the adhesion force for liquid-water droplets, and to understand the droplets? growth and detachment from the gas-diffusion layers.

Das, Prodip K.; Grippin, Adam; Weber, Adam Z.

2011-07-01T23:59:59.000Z

396

Experiments and Direct Numerical Simulations of binary collisions of miscible liquid droplets with different viscosities  

E-Print Network (OSTI)

Binary droplet collisions are of importance in a variety of practical applications comprising dispersed two-phase flows. The background of our research is the prediction of properties of particulate products formed in spray processes. To gain a more thorough understanding of the elementary sub-processes inside a spray, experiments and direct numerical simulations of binary droplet collisions are used. The aim of these investigations is to develop semi-analytical descriptions for the outcome of droplet collisions. Such collision models can then be employed as closure terms for scale-reduced simulations. In the present work we focus on the collision of droplets of different liquids. These kinds of collisions take place in every spray drying process when droplets with different solids contents collide in recirculation zones. A new experimental method has been developed allowing for high spatial and time resolved recordings via Laser-induced fluorescence. The results obtained with the proposed method will be comp...

Focke, C

2012-01-01T23:59:59.000Z

397

On-Demand Generation of Monodisperse Femtoliter Droplets by Shape-Induced Shear  

SciTech Connect

We describe a method for creating discrete femtoliter-scale water-in-oil droplets on demand, based solely on a geometrically induced reduction in oil/water interfacial area at microfabricated junction orifices. This on-demand generation method is driven by self-shear of droplets due to interfacial tension induced forces resulting from a localized transition in microchannel height. The magnitudes of shear stresses involved appear to be significantly less than the shearing instabilities used to split off daughter droplets from aqueous mother plugs at microfabricated junctions in continuous water-in-oil segmented flows, which implies that this method may be better suited for studying biochemical reactions and reaction kinetics in droplets of decreased volume without loss of chemical reactivity due to redistribution of surfactant density used to passivate the oil/water interface. Predictable droplet generation rates under constant pressure conditions or the gated formation of one, two or more droplets at a time with fixed pressure pulses have been demonstrated in a similar manner to active on-demand droplet generation strategies, but with a simpler system not needing actuation and sensing equipment beyond a pressure regulator.

Collier, Pat [ORNL; Retterer, Scott T [ORNL; Jung, Seung-Yong [ORNL

2010-01-01T23:59:59.000Z

398

On the Combined Effects of Turbulence and Gravity on Droplet Collisions in Clouds: A Numerical Study  

Science Conference Proceedings (OSTI)

This paper examines the combined influences of turbulence and gravity on droplet collision statistics in turbulent clouds by means of direct numerical simulation (DNS). The essential microphysical mechanisms that determine the geometric collision ...

Eric J. P. Woittiez; Harm J. J. Jonker; Luís M. Portela

2009-07-01T23:59:59.000Z

399

Dynamic Response of Quartz Crystal Microbalances in contact with Silicone Oil Droplets  

E-Print Network (OSTI)

Quartz crystal microbalances (QCMs) in contact with liquid droplets have been used to investigate the rheological properties of liquids and the diverse solid-liquid interfacial phenomena. In this article, we first report ...

Zhuang, Han

400

Physico-chemical hydrodynamics of droplets on textured surfaces with engineered micro/nanostructures  

E-Print Network (OSTI)

Understanding physico-chemical hydrodynamics of droplets on textured surfaces is of fundamental and practical significance for designing a diverse range of engineered surfaces such as low-reflective, self-cleaning or ...

Park, Kyoo Chul

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

A Binned Approach to Cloud-Droplet Riming Implemented in a Bulk Microphysics Model  

Science Conference Proceedings (OSTI)

This paper presents the development and application of a binned approach to cloud-droplet riming within a bulk microphysics model. This approach provides a more realistic representation of collision–coalescence that occurs between ice and cloud ...

Stephen M. Saleeby; William R. Cotton

2008-02-01T23:59:59.000Z

402

Collisions of Small Drops in a Turbulent Flow. Part III: Relative Droplet Fluxes and Swept Volumes  

Science Conference Proceedings (OSTI)

Swept volumes of cloud droplets with radii below 20 ?m are calculated under conditions typical of atmospheric cloud turbulence characterized by enormous values of Reynolds numbers, high turbulent intermittency, and characteristic values of the ...

M. B. Pinsky; A. P. Khain; B. Grits; M. Shapiro

2006-08-01T23:59:59.000Z

403

Theoretical Formulation of Collision Rate and Collision Efficiency of Hydrodynamically Interacting Cloud Droplets in Turbulent Atmosphere  

Science Conference Proceedings (OSTI)

A methodology for conducting direct numerical simulations (DNSs) of hydrodynamically interacting droplets in the context of cloud microphysics has been developed and used to validate a new kinematic formulation capable of describing the collision ...

Lian-Ping Wang; Orlando Ayala; Scott E. Kasprzak; Wojciech W. Grabowski

2005-07-01T23:59:59.000Z

404

CCN and Vertical Velocity Influences on Droplet Concentrations and Supersaturations in Clean and Polluted Stratus Clouds  

Science Conference Proceedings (OSTI)

Cloud microphysics and CCN measurements from two marine stratus cloud projects are presented and analyzed. Results show that the increase of cloud droplet concentrations (Nc) withCCN concentrations (NCCN) rolls off for NCCN at 1% supersaturation (...

James G. Hudson; Stephen Noble

405

Laboratory Studies and Numerical Simulations of Cloud Droplet Formation under Realistic Supersaturation Conditions  

Science Conference Proceedings (OSTI)

In this paper, a new device is introduced to study the formation and growth of cloud droplets under near-atmospheric supersaturations. The new device, called the Leipzig Aerosol Cloud Interaction Simulator (LACIS), is based on a laminar flow ...

F. Stratmann; A. Kiselev; S. Wurzler; M. Wendisch; J. Heintzenberg; R. J. Charlson; K. Diehl; H. Wex; S. Schmidt

2004-06-01T23:59:59.000Z

406

Cumulus Entrainment and Cloud Droplet Spectra: A Numerical Model within a Two-Dimensional Dynamical Framework  

Science Conference Proceedings (OSTI)

A simple numerical model designed to predict the evolution of cloud droplet spectra with special emphasis on the role of entrainment is developed for a case of nonprecipitating cloud. The model assumes that the cloud water mixing ratio at any ...

Jean-Louis Brenguier; Wojciech W. Grabowski

1993-01-01T23:59:59.000Z

407

Extending Twomey’s Analytical Estimate of Nucleated Cloud Droplet Concentrations from CCN Spectra  

Science Conference Proceedings (OSTI)

A fundamental but approximate formula has been established by Twomey in order to compute the nucleated cloud droplet number concentration as a function of the vertical velocity and the CCN (cloud condensation nuclei) characteristics expressed by ...

Jean-Martial Cohard; Jean-Pierre Pinty; Carole Bedos

1998-11-01T23:59:59.000Z

408

Magnetic detection of underground pipe using timed-release marking droplets  

DOE Patents (OSTI)

A system 10 and method of detecting an underground pipe 12 injects magnetic marking droplets 16 into the underground pipe 12 which coat the inside of the pipe 12 and may be detected from aboveground by a magnetometer 28. The droplets 16 include a non-adhesive cover 32 which allows free flow thereof through the pipe 12, with the cover 32 being ablatable for the timed-release of a central core 30 containing magnetic particles 30a which adhere to the inside of the pipe 12 and are detectable from aboveground. The rate of ablation of the droplet covers 32 is selectively variable to control a free flowing incubation zone 12a for the droplets 16 and a subsequent deposition zone 12b in which the magnetic particles 30a are released for coating the pipe 12.

Powell, James R. (Shoreham, NY); Reich, Morris (Kew Garden Hills, NY)

1996-12-17T23:59:59.000Z

409

Evaporation and Condensation of Large Droplets in the Presence of Inert Admixtures Containing Soluble Gas  

Science Conference Proceedings (OSTI)

In this study the mutual influence of heat and mass transfer during gas absorption and evaporation or condensation on the surface of a stagnant droplet in the presence of inert admixtures containing noncondensable soluble gas is investigated ...

T. Elperin; A. Fominykh; B. Krasovitov

2007-03-01T23:59:59.000Z

410

Three-dimensional numerical investigation of a droplet impinging normally onto a wall film  

SciTech Connect

The paper presents a three-dimensional numerical investigation of a droplet impinging normally onto a wall film. The numerical method is based on the finite volume solution of the Navier-Stokes equations coupled with the volume of fluid method (VOF) and utilizing an adaptive local grid refinement technique for tracking more accurately the liquid-gas interface. The results are compared with available experimental data for integral quantities such as the lamella temporal development. Two mechanisms are identified leading to secondary droplet formation; in the initial and intermediate stages of splashing secondary droplet formation is according to Rayleigh instability while at later times surface tension effects contribute further to secondary atomization. Moreover, the influence of Weber number on the impingement process is investigated and correlations for the diameter and number of secondary droplets are proposed.

Nikolopoulos, N. [Department of Mechanical Engineering, Nat. Technical University of Athens, 15740 Zografos (Greece)]. E-mail: niknik@fluid.mech.ntua.gr; Theodorakakos, A. [Fluid Research Co., H. Trikoupi 25, Athens, 10681 (Greece)]. E-mail: andreas@fluid-research.com; Bergeles, G. [Department of Mechanical Engineering, Nat. Technical University of Athens, 15740 Zografos (Greece)]. E-mail: bergeles@fluid.mech.ntua.gr

2007-07-01T23:59:59.000Z

411

Development of a uniform-droplet spray apparatus for high melting temperature metals  

E-Print Network (OSTI)

The building and operation of a high-temperature uniform droplet spraying (UDS) apparatus extend the performance and capabilities of powder based manufacturing processes. Although the main concepts of operation of the ...

Joumaa, Hady K

2005-01-01T23:59:59.000Z

412

System for sensing droplet formation time delay in a flow cytometer  

DOE Patents (OSTI)

A droplet flow cytometer system which includes a system to optimize the droplet formation time delay based on conditions actually experienced includes an automatic droplet sampler which rapidly moves a plurality of containers stepwise through the droplet stream while simultaneously adjusting the droplet time delay. Through the system sampling of an actual substance to be processed can be used to minimize the effect of the substances variations or the determination of which time delay is optimal. Analysis such as cell counting and the like may be conducted manually or automatically and input to a time delay adjustment which may then act with analysis equipment to revise the time delay estimate actually applied during processing. The automatic sampler can be controlled through a microprocessor and appropriate programming to bracket an initial droplet formation time delay estimate. When maximization counts through volume, weight, or other types of analysis exists in the containers, the increment may then be reduced for a more accurate ultimate setting. This may be accomplished while actually processing the sample without interruption.

Van den Engh, Ger (Seattle, WA); Esposito, Richard J. (Seattle, WA)

1997-01-01T23:59:59.000Z

413

On-chip real-time single-copy polymerase chain reaction in picoliter droplets  

Science Conference Proceedings (OSTI)

The first lab-on-chip system for picoliter droplet generation and PCR amplification with real-time fluorescence detection has performed PCR in isolated droplets at volumes 10{sup 6} smaller than commercial real-time PCR systems. The system utilized a shearing T-junction in a silicon device to generate a stream of monodisperse picoliter droplets that were isolated from the microfluidic channel walls and each other by the oil phase carrier. An off-chip valving system stopped the droplets on-chip, allowing them to be thermal cycled through the PCR protocol without droplet motion. With this system a 10-pL droplet, encapsulating less than one copy of viral genomic DNA through Poisson statistics, showed real-time PCR amplification curves with a cycle threshold of {approx}18, twenty cycles earlier than commercial instruments. This combination of the established real-time PCR assay with digital microfluidics is ideal for isolating single-copy nucleic acids in a complex environment.

Beer, N R; Hindson, B; Wheeler, E; Hall, S B; Rose, K A; Kennedy, I; Colston, B

2007-04-20T23:59:59.000Z

414

Spatially resolved temperature and heat flux measurements for slow evaporating droplets heated by a microfabricated heater array  

E-Print Network (OSTI)

The evaporation phenomenon of a liquid droplet was investigated by using microfabricated heaters. All 32 microheaters were designed to have the same resistance. Gold microheaters worked both as temperature indicators and as heaters. The first experiment was performed under a constant voltage mode to investigate the temperature and heat flux variation of the heated surface by the evaporating droplet. The second experiment was performed under constant temperature mode to investigate the spatial and temporal heat flux variation of the constant temperature heater surface by the evaporating droplet heater. Droplet evaporation was recorded with a CCD camera. Experimental data showed temperature and heat flux variations inside and outside of the droplet with respect to time and radial position from the center of the droplet by tomographic deconvolution.

Paik, Sokwon

415

1999 Commercial Buildings Characteristics--Building Size  

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

Size of Buildings Size of Buildings Size of Buildings The 1999 CBECS estimated that 2,348,000 commercial buildings, or just over half (50.4 percent) of total buildings, were found in the smallest building size category (1,001 to 5,000 square feet) (Figure 1). Only 7,000 buildings occupied the largest size category (over 500,000 square feet). Detailed tables Figure 1. Distribution of Buildings by Size of Building, 1999 Figure 1. Distribution of Buildings by Size of Building, 1999. If having trouble viewing this page, please contact the National Energy Information Center at (202) 586-8800. Energy Information Administration Commercial Buildings Energy Consumption Survey The middle size categories (10,001 to 100,000 square feet) had relatively more floorspace per category than smaller or larger size categories (Figure 2). The greatest amount of floorspace, about 11,153,000 square feet (or 17 percent of total floorspace) was found in the 10,001 to 25,000 square feet category. Figure 2. Distribution of Floorspace by Size of Building, 1999

416

Controlled emulsion droplet solvent evaporation for particle production  

E-Print Network (OSTI)

In this work, we are motivated by the need to produce particles of well-controlled size, shape and morphology for general application in catalysis, environmental remediation, nanomedicine, pharmaceuticals, the development ...

Chang, Emily P

2013-01-01T23:59:59.000Z

417

High-Temperature Microfluidic Synthesis of CdSe Nanocrystals inNanoliter Droplets  

SciTech Connect

The high-temperature synthesis of CdSe nanocrystals innanoliter-volume droplets flowing in a perfluorinated carrier fluidthrough a microfabricated reactor is presented. A flow-focusing nanojetstructure with a step increase in channel height reproducibly generatedoctadecene droplets in Fomblin Y 06/6 perfluorinated polyether atcapillary numbers up to 0.81 and with a droplet:carrier fluid viscosityratio of 0.035. Cadmium and selenium precursors flowing in octadecenedroplets through a high-temperature (240-300 degrees C) glassmicroreactor produced high quality CdSe nanocrystals, as verified byoptical spectroscopy and transmission electron microscopy. Isolating thereaction solution in droplets prevented particle deposition andhydrodynamic dispersion, allowing the reproducible synthesis ofnanocrystals at three different temperatures and four different residencetimes in the span of four hours. Our synthesis of a wide range ofnanocrystals at high temperatures, high capillary numbers, and lowviscosity ratio illustrates the general utility of droplet-basedmicrofluidic reactors to encapsulate nanoliter volumes of organic oraqueous solutions and to precisely control chemical or biochemicalreactions.

Chan, Emory M.; Alivisatos, A. Paul; Mathies, Richard A.

2005-06-09T23:59:59.000Z

418

Synchronized droplet size measurements for coal-water-slurry (CWS) diesel sprays of an electronically-controlled fuel injection system  

DOE Green Energy (OSTI)

Experiments were completed to study intermittent coal-water slurry (CWS) fuel sprays injected from an electronically-controlled accumulator injector system. A laser diffraction particle analyzing (LDPA) technique was used to measure the spray diameters (Sauter mean diameter, SMD) assuming the Rosin-Rammler two parameter model. In order to ensure an accurate synchronization of the measurement with the intermittent sprays, a new synchronization technique was developed using the light extinction signal as a triggering source for the data taking initiation. This technique allowed measurement of SMDs near the spray tip where the light extinction was low and the data were free from the multiscattering bias. Coal-water slurry fuel with 50% coal loading in mass containing 5 {mu}m mass median diameter coal particulates was considered. Injection pressures ranging from 28 to 110 MPa, two different nozzle orifice diameters, 0.2 ad 0.4 mm, and four axial measurement locations from 60 to 120 mm from the nozzle orifice were studied. Measurements were made for pressurized (2.0 MPa in gauge) and for ambient chamber conditions. The spray SMD showed an increase with the distance of the axial measurement location and with the ambient gas density, and showed a decrease with increasing injection pressure. A correlation of the Sauter mean diameter with the injection conditions was determined. The results were also compared with previous SMD correlations that were available only for diesel fuel sprays.

Kihm, K.D.; Terracina, D.P.; Payne, S.E.; Caton, J.A. [Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering

1993-12-31T23:59:59.000Z

419

Properly synchronized measurements of droplet sizes for high-pressure intermittent coal-water slurry fuel sprays  

DOE Green Energy (OSTI)

Experiments were completed to study intermittent coal-water slurry (CWS) fuel sprays injected from an electronically-controlled accumulator injector system. A new synchronization technique was developed using the light extinction signal as a triggering source for the data taking initiation with a laser diffraction particle analyzing (LDPA) technique. This technique allowed measurement of SMDs near the spray tip where the light extinction was low and the data were free from the multiscattering bias. Coal-water slurry fuel with 50% coal loading in mass containing 5 {mu}m mass median diameter coal particulates was considered. A correlation of the SMD with the injection conditions was determined which should show a satisfactory agreement with the measured SMD data. The spray SMD showed an increase with the distance of the axial measurement location and with the ambient gas density, and showed a decrease with increasing injection pressure.

Kihm, K.D.; Terracina, D.P.; Payne, S.E.; Caton, J.A. [Texas A and M Univ., College Station, TX (United States)

1993-12-31T23:59:59.000Z

420

Characterization,demulsification and transportation of heavy crude oil: Pipeline trasportation; emulsion stability; demulsification; droplet size; shear stress & shear rate  

Science Conference Proceedings (OSTI)

Stable concentrated oil-in-water (O/W) emulsions were prepared and their application for heavy oil pipeline transportation was investigated using very viscous Malaysian heavy crude oil. Two Malaysian heavy crude oil samples, Tapis and a blend of Tapis ...

Abdurahman H. Nour; Chew Fern Tan; Azhari H. Nour

2012-02-01T23:59:59.000Z

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


421

An Observed Signature of Aerosol Effect on Cloud Droplet Radii from a  

NLE Websites -- All DOE Office Websites (Extended Search)

An Observed Signature of Aerosol Effect on Cloud Droplet Radii from a An Observed Signature of Aerosol Effect on Cloud Droplet Radii from a Decade of Observations at a Mid-Continental Site Min, Qilong State University of New York at Albany Duan, Minzheng State University of New York at Albany Harrison, Lee State University of New York Joseph, Everette Howard University Category: Aerosols Continuing observations of aerosol and cloud optical property have been made using MFRSR and MWR at the ARM SGP site since 1993. Diurnal, monthly, seasonal and interannual variability of aerosol (optical depth and Angstrom coefficient) and cloud (optical depth and effective radius) have been analyzed. We have correlated an "aerosol index" computed from clear-sky observations of MFRSR with cloud droplet mean effective radius to study the

422

Evaporation and wetting dynamics of sessile water droplets on submicron-scale patterned silicon hydrophobic surfaces  

SciTech Connect

The evaporation characteristics of 1 l sessile water droplets on hydrophobic surfaces are experimentally examined. The proposed hydrophobic surfaces are composed of submicron diameter and 4.2- m-height silicon post arrays. A digital image analysis algorithm was developed to obtain time-dependent contact angles, contact diameters, and center heights for both non-patterned polydimethylsiloxane (PDMS) surfaces and patterned post array surfaces, which have the same hydrophobic contact angles. While the contact angles exhibit three distinct stages during evaporation in the non-patterned surface case, those in the patterned silicon post array surface case decrease linearly. In the case of post array hydrophobic surfaces, the initial contact diameter remains unchanged until the portion of the droplet above the posts completely dries out. The edge shrinking velocity of the droplet shows nonlinear characteristics, and the velocity magnitude increases rapidly near the last stage of evaporation.

Choi, Chang Kyoung [Michigan Technological University; Shin, Dong Hwan [Chung-Ang University; Lee, Seong Hyuk [Chung-Ang University; Retterer, Scott T [ORNL

2010-01-01T23:59:59.000Z

423

Deliquescence properties and particle size change of hygroscopic aerosols  

DOE Green Energy (OSTI)

Ambient aerosols frequently contain large proportions of hygroscopic inorganic salts such as sulfates and nitrates, which may induce adverse health effects upon inhalation. The inhaled salt particles are invariably exposed to a humid environment; their deposition along the respiratory tract will necessarily depend upon the size change resulting from water vapor condensation. This paper discusses the deliquescent properties of pure and mixed salt aerosols and the particle size change as a function of relative humidity. Experimental results are presented for the growth of mixed chlorides (NaCl-KCl), mixed sulfates (H{sub 2}SO{sub 4}-(NH{sub 4}){sub 2}SO{sub 4}), and mixed (NH/sub 4/){sub 2}SOsub 4}-NH{sub 4}NO{sub 3} aerosol systems. It is shown that the behavior of the mixed salt aerosols in a moist atmosphere can be predicted from phase diagrams and pertinent thermodynamic properties of the bulk solutions. The evaporation of a saline droplet in an atmosphere of decreasing humidities is also investigated experimentally. For each deliquescent salt aerosol, there is a threshold humidity below which the solution droplets will quickly evaporate to become crystalline particles. The information is useful in the selection of a suitable humidification procedure to generate test aerosols for exposure studies.

Tang, I.N.

1979-01-01T23:59:59.000Z

424

Evaporation of Picolitre Droplets on Surfaces with a Range of Wettabilities and Thermal Conductivities  

E-Print Network (OSTI)

of inkjet droplets ranges between 10 µm and 100 µm. Evaporation should still be limited by dif- fusion at this scale. Convection occurs in evaporating sessile droplets [12] where, in order to conserve mass, evaporating liquid is replenished by a convective... at 10 W for 5 minutes at different lo- cations in the reactor, resulting in different roughnesses. S1 showed a root mean squared (rms) roughness of ?130 nm by AFM (Digital Instruments Nanoscope III scanning probe microscope), whereas S2 had an RMS...

Talbot, E.L.; Berson, A.; Brown, P.S.; Bain, C.D.

2012-01-01T23:59:59.000Z

425

Oxidation Behavior of In-Flight Molten Aluminum Droplets in the Twin-Wire Electric Arc Thermal Spray Process  

Science Conference Proceedings (OSTI)

This paper examines the in-flight oxidation of molten aluminum sprayed in air using the twin-wire electric arc (TWEA) thermal spray process. The oxidation reaction of aluminum in air is highly exothermic and is represented by a heat generation term in the energy balance. Aerodynamic shear at the droplet surface enhances the amount of in-flight oxidation by: (1) promoting entrainment and mixing of the surface oxides within the droplet, and (2) causing a continuous heat generation effect that increases droplet temperature over that of a droplet without internal circulation. This continual source of heat input keeps the droplets in a liquid state during flight. A linear rate law based on the Mott-Cabrera theory was used to estimate the growth of the surface oxide layer formed during droplet flight. The calculated oxide volume fraction of an average droplet at impact agrees well with the experimentally determined oxide content for a typical TWEA-sprayed aluminum coating, which ranges from 3.3 to 12.7%. An explanation is provided for the elevated, nearly constant surface temperature (~ 2000 oC) of the droplets during flight to the substrate and shows that the majority of oxide content in the coating is produced during flight, rather than after deposition.

Donna Post Guillen; Brian G. Williams

2005-05-01T23:59:59.000Z

426

A Heuristic Method for Co-optimization of Pin Assignment and Droplet Routing in Digital Microfluidic Biochip  

Science Conference Proceedings (OSTI)

Design automation in Digital micro fluidic biochip is of immense importance in to days clinical diagnosis process. In this paper, we try to build a heuristic algorithm to simultaneously perform droplet routing and electrode actuation. The proposed method ... Keywords: Digital microfluidic biochip, Droplet routing, Pin assignment, Co-optimization heuristic

Ritwik Mukherjee; Hafizur Rahaman; Indrajit Banerjee; Tuhina Samanta; Parthasarathi Dasgupta

2012-01-01T23:59:59.000Z

427

Microsoft PowerPoint - ARM2007LetterSize.ppt  

NLE Websites -- All DOE Office Websites (Extended Search)

Remote sensing microphysical retrieval and cloud microphysics parameterizations rely on a knowledge of the shape of cloud drop size distributions (DSD). These are often...

428

State Policy: One Size Doesnt Fit All  

Wind Powering America (EERE)

Policy: One Size Doesn't Fit All Larry Flowers Deputy Director, Distributed and Community Wind American Wind Energy Association lflowers@awea.org www.awea.orgcommunitywind...

429

On-chip single-copy real-time reverse-transcription PCR in isolated picoliter droplets  

SciTech Connect

The first lab-on-chip system for picoliter droplet generation and RNA isolation, followed by reverse transcription, and PCR amplification with real-time fluorescence detection in the trapped droplets has been developed. The system utilized a shearing T-junction in a fused silica device to generate a stream of monodisperse picoliter-scale droplets that were isolated from the microfluidic channel walls and each other by the oil phase carrier. An off-chip valving system stopped the droplets on-chip, allowing thermal cycling for reverse transcription and subsequent PCR amplification without droplet motion. This combination of the established real-time reverse transcription-PCR assay with digital microfluidics is ideal for isolating single-copy RNA and virions from a complex environment, and will be useful in viral discovery and gene-profiling applications.

Beer, N R; Wheeler, E; Lee-Houghton, L; Watkins, N; Nasarabadi, S; Hebert, N; Leung, P; Arnold, D; Bailey, C; Colston, B

2007-12-19T23:59:59.000Z

430

A study of ignition and combustion characteristics of isolated coal water slurry droplet using digital image processing technique  

E-Print Network (OSTI)

A digital image processing technique is used to investigate the ignition and combustion characteristics of an isolated coal water slurry droplet in low Re flow. Coal water slurry droplet study is useful for dilute coal suspensions based on the premise that ignitability of a spray of coal water slurry must depend on the ignition characteristic of an isolated coal water slurry droplet. A flat flame burner is used for optical accessibility and also for simulating vitiated gases as existing in boiler burners. A quartz wire of 0.175 mm diameter is chosen for low thermal conductivity and to hold the droplet above theflat flame burner. The following sequence of events is observed: (i) Water first evaporates leaving agglomerated coal particle, (ii) glowing first occurs at the leading edge of the droplet, (iii) for a droplet with diameter of the order less than I mm it was observed that the volatile combustion usually occurs away from the droplet in the wake of the combustible gases made upstream, while for droplet more than I mm, the flame is attached to the particle, (iv) combustion of coal water slurry droplet is intermittent. The ignition time and volatile combustion times are obtained. Parametric studies include the effect of drop diameter and ambient oxygen concentrations. Simplified phenomen ological type models are presented in order to determine the number of particles. interparticle spacing and density of coal water slurry droplet. Finally qualitative relations between ignition and combustion times and particle diameter are obtained and the results are then compared with experimental data.

Bhadra, Tanmoy

1998-01-01T23:59:59.000Z

431

Chemical Characterization of Individual Particles and Residuals of Cloud Droplets and Ice Crystals Collected On Board Research Aircraft in the ISDAC 2008 Study  

Science Conference Proceedings (OSTI)

Although it has been shown that size of atmospheric particles has a direct correlation with their ability to act as cloud droplet and ice nuclei, the influence of composition of freshly emitted and aged particles in nucleation processes is poorly understood. In this work we combine data from field measurements of ice nucleation with chemical imaging of the sampled particles to link aerosol composition with ice nucleation ability. Field measurements and sampling were conducted during the Indirect and Semidirect Aerosols Campaign (ISDAC) over Barrow, Alaska, in the springtime of 2008. In-situ ice nucleation measurements were conducted using a Continuous Flow Diffusion Chamber (CFDC). Measured number concentrations of ice nuclei (IN) varied from frequent values of 0.01 per liter to more than 10 per liter. Residuals of airborne droplets and ice crystals were collected through a counterflow virtual impactor (CVI). The compositions of individual atmospheric particles and the residuals were studied using Computer Controlled Scanning Electron Microscopy with Energy Dispersive X-ray analysis (CCSEM/EDX) and Scanning Transmission X-ray Microscopy coupled with Near Edge X-ray Absorption Fine Structure spectroscopy (STXM/NEXAFS). Chemical analysis of cloud particle residuals collected during an episode of high ice nucleation suggests that both size and composition may influence aerosol's ability to act as IN. The STXM/NEXAFS chemical composition maps of individual residuals have characteristic structures of either inorganic or black carbon cores coated by organic materials. In a separate flight, particle samples from a biomass burning plume were collected. Although it has previously been suggested that episodes of biomass burning contribute to increased numbers of highly effective ice nuclei, in this episode we observed that only a small fraction were effective ice nuclei. Most of the particles from the biomass plume episode were smaller in size and were composed of homogeneous organic material without identifiable cores.

Hiranuma, Naruki; Brooks, Sarah D.; Moffet, Ryan C.; Glen, Andrew; Laskin, Alexander; Gilles, Marry K.; Liu, Peter; MacDonald, A. M.; Strapp, J. Walter; McFarquhar, Greg

2013-06-24T23:59:59.000Z

432

Cat heart Size  

NLE Websites -- All DOE Office Websites (Extended Search)

heart Size Name: Iris Status: student Grade: K-3 Location: OR Country: USA Date: NA Question: Can you tell me the size of a cats heart? Replies: Iris A cat's heart is about the...

433

Cat heart Size  

NLE Websites -- All DOE Office Websites (Extended Search)

Cat heart Size Name: Rebecca Status: student Grade: 6-8 Location: FL Country: USA Date: Spring 2011 Question: What is the average size of a cat's heart? Replies: Hi Rebecca, That...

434

Hopper Job Size Charts  

NLE Websites -- All DOE Office Websites (Extended Search)

charts shows the fraction of hours used on Hopper in each of 5 job-core-size bins. 2012 Usage by Job Size Chart 2011 . This chart shows the fraction of hours used on Hopper by jobs...

435

Numerical simulation of the impact and deposition of charged particulate droplets  

Science Conference Proceedings (OSTI)

This work addresses the impact and deposition of charged ''cluster-droplets'', comprised of particulates, on electrified surfaces. A direct numerical method is developed, based on an implicit, staggered, time-stepping scheme which separates the impulsive ... Keywords: Charged particulates, Clusters, Impact, Staggering scheme

T. I. Zohdi

2013-01-01T23:59:59.000Z

436

The Retrieval of Stratus Cloud Droplet Effective Radius with Cloud Radars  

Science Conference Proceedings (OSTI)

In situ samples of cloud droplets by aircraft in Oklahoma in 1997, the Surface Heat Budget of the Arctic Ocean (SHEBA)/First ISCCP Regional Experiment (FIRE)-Arctic Cloud Experiment (ACE) in 1998, and various other locations around the world were ...

Shelby Frisch; Matthew Shupe; Irina Djalalova; Graham Feingold; Michael Poellot

2002-06-01T23:59:59.000Z

437

Interface dynamics under nonequilibrium conditions: from a self-propelled droplet to dynamic pattern evolution  

E-Print Network (OSTI)

In this article, we describe the instability of a contact line under nonequilibrium conditions mainly based on the results of our recent studies. Two experimental examples are presented: the self-propelled motion of a liquid droplet and spontaneous dynamic pattern formation. For the self-propelled motion of a droplet, we introduce an experiment in which a droplet of aniline sitting on an aqueous layer moves spontaneously at an air-water interface. The spontaneous symmetry breaking of Marangoni-driven spreading causes regular motion. In a circular Petri dish, the droplet exhibits either beeline motion or circular motion. On the other hand, we show the emergence of a dynamic labyrinthine pattern caused by dewetting of a metastable thin film from the air-water interface. The contact line between the organic phase and aqueous phase forms a unique spatio-temporal pattern characterized as a dynamic labyrinthine. Motion of the contact line is controlled by diffusion processes. We propose a theoretical model to interpret essential aspects of the observed dynamic behavior.

Yong-Jun Chen; Kenichi Yoshikawa

2012-08-22T23:59:59.000Z

438

Comparison of the Theoretical Collision Efficiency of Uncharged Cloud Droplets in Horizontal and Vertical Electric Fields  

Science Conference Proceedings (OSTI)

The collision efficiency of two unchanged droplet pairs with radii combinations of (10; 9) ?m and (10; 2) ?m was computed for horizontal and vertical background electric fields ranging from 300 V m?1 to 300 kV?1. For horizontal fields, the ...

Roland List; E. Freire

1981-10-01T23:59:59.000Z

439

Local tuning of organic light-emitting diode color by dye droplet application  

E-Print Network (OSTI)

Local tuning of organic light-emitting diode color by dye droplet application T. R. Hebner and J. C and the spectra of organic light-emitting diodes made from these films can be successfully tuned by this method. S0003-6951 98 01339-4 A main goal of the field of organic light-emitting diodes OLEDs

440

Wind Tunnel Tests of the Airborne PVM-100A Response to Large Droplets  

Science Conference Proceedings (OSTI)

The Gerber Scientific, Inc. Particle Volume Monitor (PVM) is widely used to measure the liquid water content (LWC) and droplet effective radius (reff) of water clouds. The LWC response of the airborne version of this instrument, the PVM-100A, was ...

M. Wendisch; T. J. Garrett; J. W. Strapp

2002-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Abstract Electrospraying utilises electrical forces for liquid atomisation. Droplets obtained by this method  

E-Print Network (OSTI)

is the initial mass concentration of the droplets, gg is the gas dynamic viscosity, ql is the liquid density) lithium batteries- luminescence (ZnScoatedCdSe// glass) (1­4mg/CdSe/mL) (100­300°C) CdSe(inZnSmatrix)Acetonitrile+ pyridine(2:1) 3

Haile, Sossina M.

442

Ant Colony Optimization Based Droplet Routing Technique in Digital Microfluidic Biochip  

Science Conference Proceedings (OSTI)

Digital micro fluidic biochip $(DMFB)$ has gained much importance in recent times, which supports various on chip biological sample analysis. The analysis is performed on a two dimensional micro array. Significant researches are going on for high performance ... Keywords: Digital Microfluidic Biochip, ACO, Multi Objective Optimization, Droplet Routing Algorithm

Indrajit Pan; Parthasarathi Dasgupta; Hafizur Rahaman; Tuhina Samanta

2011-12-01T23:59:59.000Z

443

Two-level clustering-based techniques for intelligent droplet routing in digital microfluidic biochips  

Science Conference Proceedings (OSTI)

Current development of micro fabrication and microfluidic technology enables the digital microfluidic biochips (DMFB) to offer a platform for developing diagnostic applications with the advantages of portability, increased automation, low-power consumption, ... Keywords: Algorithms, Biochips, Clustering, Digital microfluidics, Droplet routing, EWOD, Placement

Pranab Roy; Hafizur Rahaman; Parthasarathi Dasgupta

2012-06-01T23:59:59.000Z

444

Theories of Competitive Cloud Droplet Growth and Their Application to Cloud Physics Studies  

Science Conference Proceedings (OSTI)

In a rising cloud parcel, a small droplet establishes quasi-steady-state fields of vapor density ? and temperature T around it, approximately satisfying the common relationship, 2?=2T=0, where 2 is the Laplacian operator. The fields at this ...

Norihiko Fukuta

1992-07-01T23:59:59.000Z

445

A Large-Droplet Mode and Prognostic Number Concentration of Cloud Droplets in the Colorado State University Regional Atmospheric Modeling System (RAMS). Part I: Module Descriptions and Supercell Test Simulations  

Science Conference Proceedings (OSTI)

The microphysics module of the version of the Regional Atmospheric Modeling System (RAMS) maintained at Colorado State University has undergone a series of improvements, including the addition of a large-cloud-droplet mode from 40 to 80 ?m in ...

Stephen M. Saleeby; William R. Cotton

2004-01-01T23:59:59.000Z

446

Concentrations of Sea-Spray Droplets at Various Wind Velocities: Separating Productions through Bubble Bursting and Wind Tearing  

Science Conference Proceedings (OSTI)

There are two sets of comprehensive measurements of sea spray: de Leeuw and Smith et al. Their data are interpreted to describe similar productions of film and jet drops by bursting bubbles. For measurements of Smith et al., those droplets ...

Jin Wu

2000-01-01T23:59:59.000Z

447

Collision Efficiencies of Ice Crystals at Low–Intermediate Reynolds Numbers Colliding with Supercooled Cloud Droplets: A Numerical Study  

Science Conference Proceedings (OSTI)

The efficiencies with which ice crystals at low–intermediate Reynolds numbers collide with supercooled cloud droplets are determined numerically. Three ice crystal habits are considered here: hexagonal ice plates, broad-branch crystals, and ...

Pao K. Wang; Wusheng Ji

2000-04-01T23:59:59.000Z

448

Laser-Doppler velocimeter for measuring droplet velocities in two-phase liquid-dominated nozzle flows  

DOE Green Energy (OSTI)

A new laser-Doppler velocimeter (LDV) arrangement for measuring droplet velocities in high velocity, liquid-dominated two-phase nozzle flows was developed. The transmitting optics arrangement for this LDV system is identical to that of a dual beam heterodyne LDV, i.e., the light beam from a single frequency argon laser is divided into two parallel identical beams, which are focused to an intersection volume in the flow. The light backscattered from droplets traveling through this volume is collected for analysis using a scanning confocal Fabry-Perot interferometer (FPI). Because of the dual beam arrangement an unscattered or reference beam is not necessary, and the optical alignment ease and stability are greatly improved over similar LDV-FPI systems. Results of droplet velocity measurements in high velocity, high droplet concentration nozzle jet flows are presented.

Alger, T.W.; Crowe, C.T.; Giedt, W.H.

1978-01-01T23:59:59.000Z

449

Freezing Nucleation Rates of Dilute Solution Droplets Measured between ?30° and ?40°C in Laboratory Simulations of Natural Clouds  

Science Conference Proceedings (OSTI)

A 1.2 m3 continuous slow-expansion cloud chamber was used to simulate natural, liquid cloud formation on soluble cloud condensation nuclei (CCN). Droplet freezing was observed during continued simulated adiabatic ascent and cooling to ?40°C. ...

Paul J. DeMott; David C. Rogers

1990-05-01T23:59:59.000Z

450

Determining the Susceptibility of Cloud Albedo to Changes in Droplet Concentration with the Advanced Very High Resolution Radiometer  

Science Conference Proceedings (OSTI)

Combustion Processes that Produce greenhouse gases also increase cloud condensation nuclei (CCN) concentrations, which in turn increase cloud droplet concentrations and thereby cloud albedo. A calculation of cloud susceptibility, defined in this ...

S. Platnick; S. Twomey

1994-03-01T23:59:59.000Z

451

How Well Does Water Activity Determine Homogeneous Ice Nucleation Temperature in Aqueous Sulfuric Acid and Ammonium Sulfate Droplets?  

Science Conference Proceedings (OSTI)

Frozen fraction measurements made using a droplet free-fall freezing tube apparatus are presented and used, along with other recent laboratory measurements, to evaluate how well both the water activity idea and the translated melting-point curve ...

Brian D. Swanson

2009-03-01T23:59:59.000Z

452

Calculation of two-phase dispersed droplet-in-vapor flows including normal shock waves  

DOE Green Energy (OSTI)

A method for calculating quasi-one-dimensional, steady-state, two-phase dispersed droplet-in-vapor flow has been developed. The technique is applicable to both subsonic and supersonic single component flow in which normal shock waves may occur, and is the basis for a two-dimensional model. The flow is assumed to be inviscid except for droplet drag. Temperature and pressure equilibrium between phases is assumed, although this is not a requirement of the technique. Example calculations of flow in one-dimensional nozzles with and without normal shocks are given and compared with experimentally measured pressure profiles for both low quality and high quality two-phase steam/water flow.

Comfort, W.J.; Alger, T.W.; Giedt, W.H.; Crowe, C.T.

1976-07-28T23:59:59.000Z

453

Simulation of a moving liquid droplet inside a rarefied gas region  

E-Print Network (OSTI)

We study the dynamics of a liquid droplet inside a gas over a large range of the Knudsen numbers. The moving liquid droplet is modeled by the incompressible Navier-Stokes equations, the surrounding rarefied gas by the Boltzmann equation. The interface boundary conditions between the gas and liquid phases are derived. The incompressible Navier-Stokes equations are solved by a meshfree Lagrangian particle method called Finite Pointset Method (FPM), and the Boltzmann equation by a DSMC type of particle method. To validiate the coupled solutions of the Boltzmann and the incompressible Navier-Stokes equations we have further solved the compressible and the incompressible Navier-Stokes equations in the gas and liquid phases, respectively. In the latter case both the compressible and the incompressible Navier-Stokes equations are also solved by the FPM. In the continuum regime the coupled solutions obtained from the Boltzmann and the incompressible Navier-Stokes equations match with the solutions obtained from the c...

Tiwari, Sudarshan; Hardt, Steffen

2012-01-01T23:59:59.000Z

454

Droplets moving on a fluid surface: interference pattern from two slits  

E-Print Network (OSTI)

The Feynman path integral approach for solving the motion of a droplet along a silicon oil surface is developed by replacing the Planck constant by a surrogate parameter. The latter is proportional to the surface tension of the silicon oil multiplied by the area of the thin air film, separating the droplet from the oil, and by the half-period of the Faraday oscillations. It is shown that the Navier-Stokes equation together with the mass conservation equation can be reduced to the Schr\\"{o}dinger equation when the surrogate parameter replaces the Planck constant. The Feynman path integral underlying the Schr\\"{o}dinger equation is used then to calculate a wave function that plays the role of the de Broglie pilot-wave.

Sbitnev, Valeriy I

2013-01-01T23:59:59.000Z

455

Droplets moving on a fluid surface: interference pattern from two slits  

E-Print Network (OSTI)

The Feynman path integral approach for solving the motion of a droplet along a silicon oil surface is developed by replacing the Planck constant by a surrogate parameter. The latter is proportional to the surface tension of the silicon oil multiplied by the area of the thin air film, separating the droplet from the oil, and by the half-period of the Faraday oscillations. It is shown that the Navier-Stokes equation together with the mass conservation equation can be reduced to the Schr\\"{o}dinger equation when the surrogate parameter replaces the Planck constant. The Feynman path integral underlying the Schr\\"{o}dinger equation is used then to calculate a wave function that plays the role of the de Broglie pilot-wave.

Valeriy I. Sbitnev

2013-07-26T23:59:59.000Z

456

Transport of radioactive droplet moisture from a source in a nuclear power plant spray pond  

Science Conference Proceedings (OSTI)

In addition to a change in the microclimate in the region surrounding a nuclear power plant resulting from the emission of vapor form a cooling tower, evaporation of water from the water surface of a cooling pond or a spray pond, in the latter case direct radioactive contamination of the underlying surface around the nuclear power plant can also occur due to discharge of process water (radioactive) into the pond and its transport in the air over a certain distance in the form of droplet moisture. A typical example may be the situation at the Zaporozhe nuclear power plant in 1986 when accidental discharge of process water into the cooling pond occurred. Below we present a solution for the problem of transport of droplet moisture taking into account its evaporation, which may be used to estimate the scale of radioactive contamination of the locality.

Elokhin, A.P.

1995-11-01T23:59:59.000Z

457

Technology Innovation: Proceedings: International Conference on Solid Particle and Liquid Droplet Erosion  

Science Conference Proceedings (OSTI)

Solid particle erosion (SPE) and liquid droplet erosion (LDE) damage in steam and gas turbines can result in costly replacement or repair. Equipment manufacturers and aftermarket vendors often develop new materials and erosion-resistant coatings to address these two forms of damage, but for utilities, selection of a new material or coating from among multiple options is not always straightforward. A standardized methodology allowing direct comparison of materials/coatings that address high-temperature SP...

2012-07-25T23:59:59.000Z

458

Nuclear mass systematics by complementing the Finite Range Droplet Model with neural networks  

E-Print Network (OSTI)

A neural-network model is developed to reproduce the differences between experimental nuclear mass-excess values and the theoretical values given by the Finite Range Droplet Model. The results point to the existence of subtle regularities of nuclear structure not yet contained in the best microscopic/phenomenological models of atomic masses. Combining the FRDM and the neural-network model, we create a hybrid model with improved predictive performance on nuclear-mass systematics and related quantities.

S. Athanassopoulos; E. Mavrommatis; K. A. Gernoth; J. W. Clark

2005-11-30T23:59:59.000Z

459

Stability and instability of a hot and dilute nuclear droplet. II. Dissipative isoscalar modes  

E-Print Network (OSTI)

Results on dissipative isoscalar modes of a hot and dilute nuclear droplet are presented. As compared to the adiabatic limit (part I), realistic dissipation yields a substantial reduction of the growth rates for all unstable modes, while the area of spinodal instability in the ($\\varrho$,T)-plane remains unchanged. The qualitative features of multifragmentation through spinodal decomposition as obtained in the adiabatic limit are not significantly affected by dissipation.

W. Nörenberg; G. Papp; P. Rozmej

2002-01-10T23:59:59.000Z

460

High temperature size selective membranes  

DOE Green Energy (OSTI)

The objective of this research is to develop a high temperature size selective membrane capable of separating gas mixture components from each other based on molecular size, using a molecular sieving mechanism. The authors are evaluating two concepts: a composite of a carbon molecular sieve (CMS) with a tightly defined pore size distribution between 3 and 4 {angstrom}, and a microporous supporting matrix which provides mechanical strength and resistance to thermal degradation, and a sandwich of a CMS film between the porous supports. The high temperature membranes the authors are developing can be used to replace the current low-temperature unit operations for separating gaseous mixtures, especially hydrogen, from the products of the water gas shift reaction at high temperatures. Membranes that have a high selectivity and have both thermal and chemical stability would improve substantially the economics of the coal gasification process. These membranes can also improve other industrial processes such as the ammonia production and oil reform processes where hydrogen separation is crucial. Results of tests on a supported membrane and an unsupported carbon film are presented.

Yates, S.F.; Zhou, S.J.; Anderson, D.J.; Til, A.E. van

1994-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "droplet size distribution" 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

Strategy Guideline: HVAC Equipment Sizing  

SciTech Connect

The heating, ventilation, and air conditioning (HVAC) system is arguably the most complex system installed in a house and is a substantial component of the total house energy use. A right-sized HVAC system will provide the desired occupant comfort and will run efficiently. This Strategy Guideline discusses the information needed to initially select the equipment for a properly designed HVAC system. Right-sizing of an HVAC system involves the selection of equipment and the design of the air distribution system to meet the accurate predicted heating and cooling loads of the house. Right-sizing the HVAC system begins with an accurate understanding of the heating and cooling loads on a space; however, a full HVAC design involves more than just the load estimate calculation - the load calculation is the first step of the iterative HVAC design procedure. This guide describes the equipment selection of a split system air conditioner and furnace for an example house in Chicago, IL as well as a heat pump system for an example house in Orlando, Florida. The required heating and cooling load information for the two example houses was developed in the Department of Energy Building America Strategy Guideline: Accurate Heating and Cooling Load Calculations.

Burdick, A.

2012-02-01T23:59:59.000Z

462

Droplet minimizers for the Gates-Lebowitz-Penrose free energy functional  

E-Print Network (OSTI)

We study the structure of the constrained minimizers of the Gates-Lebowitz-Penrose free-energy functional ${\\mathcal F}_{\\rm GLP}(m)$, non-local functional of a density field $m(x)$, $x\\in {\\mathcal T}_L$, a $d$-dimensional torus of side length $L$. At low temperatures, ${\\mathcal F}_{\\rm GLP}$ is not convex, and has two distinct global minimizers, corresponding to two equilibrium states. Here we constrain the average density $L^{-d}\\int_{{\\cal T}_L}m(x)\\dd x$ to be a fixed value $n$ between the densities in the two equilibrium states, but close to the low density equilibrium value. In this case, a "droplet" of the high density phase may or may not form in a background of the low density phase, depending on the values $n$ and $L$. We determine the critical density for droplet formation, and the nature of the droplet, as a function of $n$ and $L$. The relation between the free energy and the large deviations functional for a particle model with long-range Kac potentials, proven in some cases, and expected to be true in general, then provides information on the structure of typical microscopic configurations of the Gibbs measure when the range of the Kac potential is large enough.

E. A. Carlen; M. C. Carvalho; R. Esposito; J. L. Lebowitz; R. Marra

2009-05-21T23:59:59.000Z

463

Unusually high (oxidizer/Pu) ratios in the macro-residues from plutonium-droplet combustion  

Science Conference Proceedings (OSTI)

Individual submillimeter-diameter droplets of /sup 239/Pu-0.6w/o Ga alloy were laser ignited and burned during free fall through air. As with a number of other active metals, plutonium droplets burn as coherent, intensely incandescent bodies that explode near the end of combustion. Compared to many other metals, however, the explosive event with plutonium droplets is relatively mild, and, in most experiments, an essentially intact spherule of oxidized material can be retrieved afterward from the combustion chamber. The oxidizer-to-plutonium atomic ratios (O/Pu) of the exploded spherules retrieved in the experiments seem unusually high - from 3- to 5-fold greater than the pre-explosion ratios. Some possible explanations of the high apparent O/Pu ratios are: (1) the particles may have become contaminated after the explosion but before the microweighing; (2) the analyses may have been performed with only partially dissolved specimens; (3) one or more elements heavier than the oxidizer elements (i.e. Ga) may have concentrated in the post explosion residue, giving a false indication of the O/Pu ratio; (4) the specimens may be supersaturated or otherwise metastable solutions of oxygen or other oxidizers quenched in at combustion temperatures; or (5) there might be hitherto unknown hyperstoichiometric oxygen and/or nitrogen compounds of plutonium which form at high temperatures. (JMT)

Nelson, L.S.

1980-12-01T23:59:59.000Z

464

Land animal sizes  

NLE Websites -- All DOE Office Websites (Extended Search)

Land animal sizes Name: tamar c Status: NA Age: NA Location: NA Country: NA Date: Around 1993 Question: Why are today's land mammals so much smaller than prehistoric mammals?...

465

ARM - Measurement - Hydrometeor size  

NLE Websites -- All DOE Office Websites (Extended Search)

size size ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Hydrometeor size The size of a hydrometeor, measured directly or derived from other measurements . Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments DISDROMETER : Impact Disdrometer LDIS : Laser Disdrometer External Instruments CPOL : C-Band Polarimetric Radar Field Campaign Instruments EC-CONVAIR580-BULK : Environment Canada Convair 580 Bulk Parameters

466

Distributed Sensor Coordination for Advanced Energy Systems  

NLE Websites -- All DOE Office Websites (Extended Search)

Distributed Sensor Coordination for Advanced Energy Systems Background As advanced energy systems grow in size, they require an increasing number of pressure, temperature, and...

467

Sizing and burn time measurements of micron-sized metal powders  

SciTech Connect

Detailed ignition and combustion mechanisms are needed to develop optimized propellant and energetic formulations using micron-sized metal powders, such as aluminum. Combustion researchers have traditionally used relatively coarse metal particles to characterize the burn time dependence on particle size. However, measurements of burn times for particles below 10 {mu}m in diameter are still needed for aluminum powders and other metal fuels. The apparatus described here sizes the particles just before the ignition event, providing a direct correlation between individual particle size and its burn time. Two lasers were utilized: a 785 nm laser diode for sizing the particles and a 125 W CO{sub 2} laser for particle ignition. The particles crossed the 785 nm laser beam just before crossing the CO{sub 2} laser beam. The particle size was determined from the amplitude of the scattered 785 nm light pulse. The burn time was determined from the duration of the visible light emission produced from the ignited particle. The in situ measured particle size distributions compared well with the size distributions measured for the same powders by a commercial instrument using low angle laser light scattering. Our measurements with two nominally spherical aluminum powders, suggest that the burn times increase from 0.5 to {approx}2.5 ms as the particle diameters increase from 3 to 8 {mu}m.

Gill, Robert J.; Mohan, Salil; Dreizin, Edward L. [New Jersey Institute of Technology Newark, New Jersey 07102 (United States)

2009-06-15T23:59:59.000Z

468

Size-dependent piezoelectricity  

E-Print Network (OSTI)

In this paper, a consistent theory is developed for size-dependent piezoelectricity in dielectric solids. This theory shows that electric polarization can be generated as the result of coupling to the mean curvature tensor, unlike previous flexoelectric theories that postulate such couplings with other forms of curvature and more general strain gradient terms ignoring the possible couple- stresses. The present formulation represents an extension of recent work that establishes a consistent size-dependent theory for solid mechanics. Here by including scale-dependent measures in the energy equation, the general expressions for force- and couple-stresses, as well as electric displacement, are obtained. Next, the constitutive relations, displacement formulations, the uniqueness theorem and the reciprocal theorem for the corresponding linear small deformation size-dependent piezoelectricity are developed. As with existing flexoelectric formulations, one finds that the piezoelectric effect can also exist in isotrop...

Hadjesfandiari, Ali R

2013-01-01T23:59:59.000Z

469

Genetic algorithm for optimal capacitor allocation in radial distribution systems  

Science Conference Proceedings (OSTI)

Optimum location and size of capacitors for a radial distribution system is presented. In the present study capacitor sizes are assumed as discrete known variables, which are to be placed on the buses such that it reduces the losses of the distribution ... Keywords: capacitor placement, distribution automation (DA), genetic algorithm (GA), loss minimisation, optimisation, power distribution system

K. S. Swarup

2005-06-01T23:59:59.000Z

470

Structure of droplet-epitaxy-grown InAs/GaAs quantum dots  

Science Conference Proceedings (OSTI)

We have used a direct x-ray phasing method, coherent Bragg rod analysis, to obtain sub-angstrom resolution electron density maps of the InAs/GaAs dot system. The dots were grown by the droplet heteroepitaxy (DHE) technique and their structural and compositional properties are compared with those of dots grown by the strain-driven Stranski-Krastanov method. Our results show that the Ga diffusion into the DHE-grown dots is somewhat larger; however, other characteristics such as the composition of the dots uppermost layers, the interlayer spacing, and the bowing of the atomic layers are similar.

Cohen, Eyal; Yochelis, Shira; Westreich, Ohad; Shusterman, Sergey; Kumah, Divine P.; Clarke, Roy; Yacoby, Yizhak; Paltiel, Yossi (Michigan); (Hebrew); (Soreq NRC, Israel)

2011-09-06T23:59:59.000Z

471

Packaging a liquid metal ESD with micro-scale Mercury droplet.  

SciTech Connect

A liquid metal ESD is being developed to provide electrical switching at different acceleration levels. The metal will act as both proof mass and electric contact. Mercury is chosen to comply with operation parameters. There are many challenges surrounding the deposition and containment of micro scale mercury droplets. Novel methods of micro liquid transfer are developed to deliver controllable amounts of mercury to the appropriate channels in volumes under 1 uL. Issues of hermetic sealing and avoidance of mercury contamination are also addressed.

Barnard, Casey Anderson

2011-08-01T23:59:59.000Z

472

ARM - PI Product - In-Situ Microphysics from the MPACE IOP  

NLE Websites -- All DOE Office Websites (Extended Search)

Description Best estimates of the size distributions of supercooled water droplets and ice crystals for mixed-phase clouds measured during M-PACE for spiral ascentsdescents...

473

ARM - Publications: Science Team Meeting Documents: Response...  

NLE Websites -- All DOE Office Websites (Extended Search)

variations in cloud droplet size distribution Barker, Howard Meteorological Service of Canada Cole, Jason Meteorological Service of Canada Marshak, Alexander NASA Goddard Space...

474

Particle Size Analysis of Multimodal Gamma-Prime (?') Distributions ...  

Science Conference Proceedings (OSTI)

Evolution of Internal Strain with Temperature in Depleted Uranium in the Presence of Hydrides · EXAFS Study of Local Atomic Environment in Annealed and ...

475

Certification of SRM 114q: Part II (Particle size distribution)  

Science Conference Proceedings (OSTI)

... LA: Ronald J. Rajki California Portland Cement ... Mitsubishi Cement Corp., Lucerne Valley, CA: Tom ... of diffracted light around the central beam can ...

2006-12-07T23:59:59.000Z

476

The geographic distribution of mammal body size in Europe  

E-Print Network (OSTI)

palaeo/ice_topo. 2 Heat conservation — grid cell averages ofgrid cell from data available at: http:// www.ngdc.noaa.gov/seg/cdroms/ged_iia/datasets/a13/fnoc.htm. 3 Heat

Rodriguez, M A; Lopez-Sanudo, I L; Hawkins, Bradford A.

2006-01-01T23:59:59.000Z

477

Comments on "Modelling the gap size distribution of parked cars"  

E-Print Network (OSTI)

In this Comment we discuss some points concerning the modeling of parked cars proposed in the article by Rawal and Rodgers, Physica A (2005). We also introduce another approach to this problem which leads to a better description of the empirical data collected by the authors.

Girardi, Mauricio

2009-01-01T23:59:59.000Z

478

Size Distribution, Imaging and Growth Mechanisms of Self ...  

Science Conference Proceedings (OSTI)

The growth of self-assembled quantum-confined structures has been under ... being developed to better understand the formation of quantum dots and wires.

479

The Echo Size Distribution of Precipitating Shallow Cumuli  

Science Conference Proceedings (OSTI)

S-band radar surveillance scans of precipitating shallow convection are analyzed. The scans are complied from 52 days of near-continuous measurements in the winter trades of the North Atlantic during the Rain in Cumulus over the Ocean (RICO) ...

Panu Trivej; Bjorn Stevens

2010-03-01T23:59:59.000Z

480

Performance Profiles Table Browser: T-10. Size Distribution of Net ...  

U.S. Energy Information Administration (EIA)

Crude oil, gasoline, heating oil, diesel, propane, and other liquids including biofuels and natural gas liquids. Natural Gas. Exploration and reserves, storage, ...

Note: This page contains sample records for the topic "droplet size distribution" 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.