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1

Consideration of Grain Size Distribution in the Diffusion of Fission Gas to Grain Boundaries  

SciTech Connect (OSTI)

We analyze the accumulation of fission gas on grain boundaries in a polycrystalline microstructure with a distribution of grain sizes. The diffusion equation is solved throughout the microstructure to evolve the gas concentration in space and time. Grain boundaries are treated as infinite sinks for the gas concentration, and we monitor the cumulative gas inventory on each grain boundary throughout time. We consider two important cases: first, a uniform initial distribution of gas concentration without gas production (correlating with post-irradiation annealing), and second, a constant gas production rate with no initial gas concentration (correlating with in-reactor conditions). The results show that a single-grain-size model, such as the Booth model, over predicts the gas accumulation on grain boundaries compared with a polycrystal with a grain size distribution. Also, a considerable degree of scatter, or variability, exists in the grain boundary gas accumulation when comparing all of the grain boundaries in the microstructure.

Paul C. Millett; Yongfeng Zhang; Michael R. Tonks; S. B. Biner

2013-09-01T23:59:59.000Z

2

Solitary dust sound waves in a plasma with two-temperature ions and distributed grain size  

SciTech Connect (OSTI)

The propagation of weakly nonlinear dust sound waves in a dusty plasma containing two different-temperature ion species is explored. The nonlinear equations describing both the quadratic and cubic plasma nonlinearities are derived. It is shown that the properties of dust sound waves depend substantially on the grain size distribution. In particular, for solitary dust sound waves with a positive potential to exist in a plasma with distributed grain size, it is necessary that the difference between the temperatures of two ion species be larger than that in the case of equal-size grains.

Prudskikh, V. V. [Southern Federal University, Research Institute of Physics (Russian Federation)

2009-01-15T23:59:59.000Z

3

The effect of grain size distribution on H$_2$ formation rate in the interstellar medium  

E-Print Network [OSTI]

The formation of molecular hydrogen in the interstellar medium takes place on the surfaces of dust grains. Hydrogen molecules play a role in gas-phase reactions that produce other molecules, some of which serve as coolants during gravitational collapse and star formation. Thus, the evaluation of the roduction rate of hydrogen molecules and its dependence on the physical conditions in the cloud are of great importance. Interstellar dust grains exhibit a broad size distribution in which the small grains capture most of the surface area. Recent studies have shown that the production efficiency strongly depends on the grain composition and temperature as well as on its size. In this paper we present a formula which provides the total production rate of H$_2$ per unit volume in the cloud, taking into account the grain composition and temperature as well as the grain size distribution. The formula agrees very well with the master equation results. It shows that for a physically relevant range of grain temperatures, the production rate of H$_2$ is significantly enhanced due to their broad size distribution.

Azi Lipshtat; Ofer Biham

2005-08-01T23:59:59.000Z

4

Crystallography of Interfaces and Grain Size Distributions in Sr-Doped LaMnO3  

E-Print Network [OSTI]

Crystallography of Interfaces and Grain Size Distributions in Sr-Doped LaMnO3 Qinyuan Liu,§ Sudip systems are similar. I. Introduction HIGH-TEMPERATURE solid oxide fuel cells (SOFCs) offer highly efficient, clean, direct conversion of chemical to electrical energy.1 SOFC performance is dictated

Rohrer, Gregory S.

6

THE IMPORTANCE OF PHYSICAL MODELS FOR DERIVING DUST MASSES AND GRAIN SIZE DISTRIBUTIONS IN SUPERNOVA EJECTA. I. RADIATIVELY HEATED DUST IN THE CRAB NEBULA  

SciTech Connect (OSTI)

Recent far-infrared (IR) observations of supernova remnants (SNRs) have revealed significantly large amounts of newly condensed dust in their ejecta, comparable to the total mass of available refractory elements. The dust masses derived from these observations assume that all the grains of a given species radiate at the same temperature, regardless of the dust heating mechanism or grain radius. In this paper, we derive the dust mass in the ejecta of the Crab Nebula, using a physical model for the heating and radiation from the dust. We adopt a power-law distribution of grain sizes and two different dust compositions (silicates and amorphous carbon), and calculate the heating rate of each dust grain by the radiation from the pulsar wind nebula. We find that the grains attain a continuous range of temperatures, depending on their size and composition. The total mass derived from the best-fit models to the observed IR spectrum is 0.019-0.13 M{sub Sun }, depending on the assumed grain composition. We find that the power-law size distribution of dust grains is characterized by a power-law index of 3.5-4.0 and a maximum grain size larger than 0.1 {mu}m. The grain sizes and composition are consistent with what is expected for dust grains formed in a Type IIP supernova (SN). Our derived dust mass is at least a factor of two less than the mass reported in previous studies of the Crab Nebula that assumed more simplified two-temperature models. These models also require a larger mass of refractory elements to be locked up in dust than was likely available in the ejecta. The results of this study show that a physical model resulting in a realistic distribution of dust temperatures can constrain the dust properties and affect the derived dust masses. Our study may also have important implications for deriving grain properties and mass estimates in other SNRs and for the ultimate question of whether SNe are major sources of dust in the Galactic interstellar medium and in external galaxies.

Temim, Tea; Dwek, Eli, E-mail: tea.temim@nasa.gov [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2013-09-01T23:59:59.000Z

7

Grain size effects on the fatigue response of nanocrystalline materials  

E-Print Network [OSTI]

The resistance of metals and alloys to fatigue crack initiation and propagation is known to be influenced significantly by grain size. Based on a wealth of experimental results obtained from microcrystalline metals, where ...

Hanlon, Timothy, 1977-

2004-01-01T23:59:59.000Z

8

Size-dependent same-material tribocharging in insulating grains  

E-Print Network [OSTI]

Observations of flowing granular matter have suggested that same-material tribocharging de- pends on particle size, rendering large grains positive and small ones negative. Models assuming the transfer of trapped electrons can explain this, but so far have not been validated. Tracking individual grains in an electric field, we show quantitatively that charge is transferred based on size between materially identical grains. However, the surface density of trapped electrons, measured independently by thermoluminescence techniques, is orders of magnitude too small to account for the scale of charge transferred. This suggests that another negatively charged species, such as ions, is responsible.

Scott R. Waitukaitis; Victor Lee; James M. Pierson; Steven L. Forman; Heinrich M. Jaeger

2014-08-07T23:59:59.000Z

9

Effects of particle size on digestion of sorghum grains  

E-Print Network [OSTI]

EFFECTS OF PARTICIE SIZE ON DIGESTION OF SORGJJJJJJ GRAINS A Thesis by REUBEN DON WALKER Submitted to the Grariuate College of Texas Af. N University in partial f'ulfillment of the requirement for the degree cf K&TER OF SCIENCE Decembe. r... 19!2 Flajor Subjert; Animal Nutrition EFFECTS OF 1'ARTICLE SIZE ON DIGESTION OF SORGHUM GRAINS A Thesis REUBEN DON WALKER Approved as to style and content by: (Chai n of Committee) (Bead or Doper ment) c (Member) , 'j ji i (Member) Deceu...

Walker, Reuben Don

1972-01-01T23:59:59.000Z

10

Is the silicate emission feature only influenced by grain size?  

E-Print Network [OSTI]

The flattening of the 10mu silicate emission feature observed in the spectra of T Tauri and Herbig Ae/Be stars is usually interpreted as an indicator of grain growth. We show in this paper that a similar behaviour of the feature shape occurs when the porosity of composite grains varies. The fluffy aggregates, having inclusions of different sizes, were modeled by multi-layered spheres consisting of amorphous carbon, amorphous silicate and vacuum. It is also found that the inclusion of crystalline silicates in composite porous particles can lead to a shift of the known resonances and production of new ones.

N. V. Voshchinnikov; Th. Henning

2008-03-31T23:59:59.000Z

11

Grain-size distributions of tsunami sediments  

E-Print Network [OSTI]

Tsunami deposits indicate that suspended load transport is the main mechanism of movement throughout a tsunami event. Recent studies have touched on whether bed load transport is also occurring, but not seen in deposits due to the high energy nature...

Spencer, Sarah

2011-08-08T23:59:59.000Z

12

8, 78477881, 2008 Size distributions  

E-Print Network [OSTI]

ACPD 8, 7847­7881, 2008 Size distributions and sources of WSOC in urban background area H. Timonen, sources and source areas of water-soluble organic carbon in urban background air H. Timonen 1 , S Chemistry Division National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80305-3000, USA

Boyer, Edmond

13

Distribution of Grain Boundary Planes and Misorientations in Magnesium Oxide  

E-Print Network [OSTI]

Distribution of Grain Boundary Planes and Misorientations in Magnesium Oxide D.M. Saylor 1 , A distribution, magnesium oxide. Abstract. We have developed a technique that allows the geometry of polycrystalline magnesium oxide. Using these data, we have specified the distribution of grain boundaries within

Rohrer, Gregory S.

14

Core, Grain-Size, and Porosity Data from the Boise Hydrogeophysical Research Site  

E-Print Network [OSTI]

.6. Grain-Size Analysis Data Sheets From Outcrops and Quarries........................66 7.7. Well Master

Barrash, Warren

15

Effect of Grain Size on Uranium(VI) Surface Complexation Kinetics...  

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

the contribution of variable grain sizes to uranium adsorptiondesorption in a sediment collected from the US DOE Hanford site. The sediment was wet-sieved into four size...

16

7, 1074310766, 2007 EC size distributions  

E-Print Network [OSTI]

ACPD 7, 10743­10766, 2007 EC size distributions in an urban atmosphere in China Xiao-Feng Huang a Creative Commons License. Atmospheric Chemistry and Physics Discussions Size distributions of elemental Correspondence to: Jian Zhen Yu (chjianyu@ust.hk) 10743 #12;ACPD 7, 10743­10766, 2007 EC size distributions

Boyer, Edmond

17

The Relationship Between Grain Boundary Energy, Grain Boundary Complexion Transitions, and Grain Size in Ca-doped Yttria  

E-Print Network [OSTI]

The Relationship Between Grain Boundary Energy, Grain Boundary Complexion Transitions, and Grain complexions. One idea is that complexion transitions occur to lower the average energy of the interface energy. Experiments on doped aluminas have shown that a complexion transition can change the relative

Rohrer, Gregory S.

18

EFFECT OF GRAIN SIZE ON THE ACOUSTIC EMISSION GENERATED DURING PLASTIC DEFORMATION OF ALUMINUM  

E-Print Network [OSTI]

PLASTIC DEFORMATION OF ALUMINUM LAWRENCE BERKELEY LABORATORYDURING PLASTIC DEFORMATION OF ALUMINUM J. Baram Materialsof polycrystalline aluminum, of different grain sizes and at

Baram, J.

2013-01-01T23:59:59.000Z

19

Secondary recrystallization in non-sag W filament wires -- On the possible role of relative grain boundary character distribution  

SciTech Connect (OSTI)

Non-Sag tungsten (W) wire is indispensable for the lighting industry. For the necessary creep resistance, large elongated grains are considered as the desired microstructure. These large grains are obtained by primary and secondary recrystallization. In the present study an effort has been made to characterize and to understand the origin of such large elongated grains. In secondary recrystallization, often called abnormal grain growth, a few of the grains grow massive. The mechanisms of normal and abnormal grain growth are essentially the same, involving high angle boundary migration and driven by the reduction of surface energy. The abnormal grain growth can be visualized as a growth advantage for a few of the grains or growth disadvantage for the majority. Such an advantage/disadvantage may be caused by (1) differences in grain size and/or (2) differences in grain boundary character distribution (GBCD). In other words, a grain may grow massive if it has large size and/or possibilities of more favorable (i.e., of higher mobility) grain boundaries with the matrix grains.

Samajdar, I. [IIT Bombay (India). Dept. of Metallurgical Engineering and Materials Science] [IIT Bombay (India). Dept. of Metallurgical Engineering and Materials Science; Verlinden, B. [Katholieke Univ. Leuven, Heverlee (Belgium)] [Katholieke Univ. Leuven, Heverlee (Belgium); Watte, P. [Philips Lighting NV, Turnhout (Belgium)] [Philips Lighting NV, Turnhout (Belgium); Mertens, F. [Philips Lighting, Maarheeze (Netherlands)] [Philips Lighting, Maarheeze (Netherlands)

1999-05-07T23:59:59.000Z

20

Effect of Grain Size on Uranium(VI) Surface Complexation Kinetics and Adsorption Additivity  

SciTech Connect (OSTI)

Laboratory experiments were performed to investigate the contribution of variable grain sizes to uranium adsorption/desorption in a sediment collected from the US DOE Hanford site. The sediment was wet-sieved into four size fractions: coarse sand (1-2 mm), medium sand (0.2-1 mm), fine sand (0.05-0.2 mm), and clay/silt fraction (< 0.05mm). For each size fraction and their composite (sediment), batch experiments were performed to determine uranium adsorption isotherms, and stirred flow-cell experiments were conducted to derive kinetic data of uranium adsorption and subsequent desorption. The results showed that uranium adsorption isotherms and adsorption/desorption kinetics were size-specific, reflecting the effects of size-specific adsorption site concentration and kinetic rate constants. The larger-size fraction had a larger mass percentage in the sediment, but with a smaller adsorption site concentration and generally a slower uranium adsorption/desorption rate. The same equilibrium surface complexation reaction and reaction constant could describe uranium adsorption isotherms for all size fractions and the composite after accounting for the effect of adsorption site concentration. Mass-weighted, linear additivity was observed for both uranium adsorption isotherms and adsorption/desorption kinetics in the composite. Our analysis also showed that uranium adsorption site concentration estimated from the adsorption isotherms was 3 orders of magnitude less than a site concentration estimated from sediment surface area and generic site density. One important implication of this study is that grain size distribution may be used to estimate uranium adsorption site, and adsorption/desorption kinetic rates in heterogeneous sediments from a common location.

Shang, Jianying; Liu, Chongxuan; Wang, Zheming; Zachara, John M.

2011-07-27T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

Effect of partial recrystallization on the grain size and grain boundary structure of austenitic steel  

SciTech Connect (OSTI)

Cyclic thermomechanical treatment combined with caliber rolling was applied in order to obtain very fine grain structure with high fraction of special grain boundaries in austenitic stainless steel. Partial recrystallization was observed. Recrystallized fraction was assessed from misorientation data measured by electron back scattering diffraction. Due to the partial recrystallization, elastic energy was stored in the deformed parts, and helped grain boundary movement. As a consequence, very fine grained material with high fraction of special boundaries was formed. - Highlights: Black-Right-Pointing-Pointer I combined the advantage of severe plastic deformation and thermomechanical treatment. Black-Right-Pointing-Pointer A very fine grained steel with high fraction of special boundaries was formed. Black-Right-Pointing-Pointer Stored elastic energy hepled the movement of grain boundaries. Black-Right-Pointing-Pointer The amount of recrystallized part was determined by EBSD.

Szabo, Peter J., E-mail: szpj@eik.bme.hu

2012-04-15T23:59:59.000Z

22

Influence of Ba content on grain size and dynamics of crystallization in barium ferrite thin films  

E-Print Network [OSTI]

Influence of Ba content on grain size and dynamics of crystallization in barium ferrite thin films of the crystallization process, which ultimately determines the grain size, were studied in barium ferrite thin films. Rapid thermal annealing was used to crystallize the amorphous as-deposited barium ferrite films

Laughlin, David E.

23

Quantifying the relative importance of flow regulation and grain size regulation of suspended sediment transport and  

E-Print Network [OSTI]

sediment transport and tracking changes in grain size of bed sediment David M. Rubin U.S. Geological Survey changes in sediment transport, it is essential to know whether transport is regulated mainly by changes in flow or by changes in grain size of sediment on the bed. In flows where changes in suspended sediment

24

Grain size dependency in sandbank modeling for the case of uniform sediment  

E-Print Network [OSTI]

Grain size dependency in sandbank modeling for the case of uniform sediment D. Idier,1 H. H. van­dependent parameters on the simulated dynamics of the sandbanks for the case of uniform sediment. The model is applied is the dominant sediment transport mode, the model taking into account the grain size dependencies gives a better

Paris-Sud XI, Université de

25

ARM - Measurement - Hydrometeor Size Distribution  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Related InformationAciddroplet sizeGeometry ARM Data

26

Effect of grain size on the melting point of confined thin aluminum films  

SciTech Connect (OSTI)

The melting of aluminum thin film was studied by a molecular dynamics (MD) simulation technique. The effect of the grain size and type of confinement was investigated for aluminum film with a constant thickness of 4?nm. The results show that coherent intercrystalline interface suppress the transition of solid aluminum into liquid, while free-surface gives melting point depression. The mechanism of melting of polycrystalline aluminum thin film was investigated. It was found that melting starts at grain boundaries and propagates to grain interiors. The melting point was calculated from the Lindemann index criterion, taking into account only atoms near to grain boundaries. This made it possible to extend melting point calculations to bigger grains, which require a long time (in the MD scale) to be fully molten. The results show that 4?nm thick film of aluminum melts at a temperature lower than the melting point of bulk aluminum (933?K) only when the grain size is reduced to 6?nm.

Wejrzanowski, Tomasz; Lewandowska, Malgorzata; Sikorski, Krzysztof; Kurzydlowski, Krzysztof J. [Materials Design Division, Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, 02-507 Warsaw (Poland)

2014-10-28T23:59:59.000Z

27

Nanostructured Ni-Co Alloys with Tailorable Grain Size and Twin Density  

E-Print Network [OSTI]

grain sizes and twin densities in the Ni-Co binary system. Using electrodeposition with various applied nanocrystalline nickel. I. INTRODUCTION BULK nanocrystalline materials are characterized by a large volume

Ferreira, Paulo J.

28

E-Print Network 3.0 - austenitc grain size Sample Search Results  

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

Dynamics of granular stratification Hernan A. Makse,1,2 Summary: camera, we study a rapid flow regime where the rolling grains size segregate during the avalanche due... measure...

29

StochasticModeling of the Independent Roles of Particle Size and Grain Size in Transgranular Cleavage Fracture  

E-Print Network [OSTI]

Cleavage Fracture TSANN LIN, A. G. EVANS, and R. O. RITCHIE The independent roles of grain size. INTRODUCTION CLEAVAGE fracture in most metals occurs by the nu- cleation of a microcrack, assisted by the local, concentrated, tensile stress exceeds some critical fracture stress. In mild steels, such microcracks were

Ritchie, Robert

30

Composition and grain size effects on the structural and mechanical properties of CuZr nanoglasses  

SciTech Connect (OSTI)

Nanoglasses (NGs), metallic glasses (MGs) with a nanoscale grain structure, have the potential to considerably increase the ductility of traditional MGs while retaining their outstanding mechanical properties. We investigated the effects of composition on the structural and mechanical properties of CuZr NG films with grain sizes between 3 to 15?nm using molecular dynamics simulations. Results indicate a transition from localized shear banding to homogeneous superplastic flow with decreasing grain size, although the critical average grain size depends on composition: 5?nm for Cu{sub 36}Zr{sub 64} and 3?nm for Cu{sub 64}Zr{sub 36}. The flow stress of the superplastic NG at different compositions follows the trend of the yield stress of the parent MG, i.e., Cu{sub 36}Zr{sub 64} yield/flow stress: 2.54?GPa/1.29?GPa and Cu{sub 64}Zr{sub 36} yield/flow stress: 3.57?GPa /1.58?GPa. Structural analysis indicates that the differences in mechanical behavior as a function of composition are rooted at the distinct statistics of prominent atomic Voronoi polyhedra. The mechanical behavior of NGs is also affected by the grain boundary thickness and the fraction of atoms at interfaces for a given average grain size. The results suggest that the composition dependence of the mechanical behavior of NGs follows that of their parent MGs, e.g., a stronger MG will generate a stronger NG, while the intrinsic tendency for homogeneous deformation occurring at small grain size is not affected by composition.

Adibi, Sara [Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore); Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore); Branicio, Paulo S., E-mail: branicio@ihpc.a-star.edu.sg; Zhang, Yong-Wei [Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore); Joshi, Shailendra P., E-mail: Shailendra@nus.edu.sg [Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore)

2014-07-28T23:59:59.000Z

31

ARM - Measurement - Cloud particle size distribution  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Related InformationAciddroplet size ARM Dataicesize distribution

32

Effect of a polynomial arbitrary dust size distribution on dust acoustic solitons  

SciTech Connect (OSTI)

The investigation of dust-acoustic solitons when dust grains are size-distributed and ions adiabatically heated is conducted. The influence of an arbitrary dust size-distribution described by a polynomial function on the properties of dust acoustic waves is investigated. An energy-like integral equation involving Sagdeev potential is derived. The solitary solutions are shown to undergo a transformation into cnoidal ones under some physical conditions. The dust size-distribution can significantly affect both lower and upper critical Mach numbers for both solitons and cnoidal solutions.

Ishak-Boushaki, M.; Djellout, D.; Annou, R. [Faculty of Physics, USTHB, P.B. 32 El Alia, Bab-ezzouar, Algiers (Algeria)

2012-07-15T23:59:59.000Z

33

Barium ferrite thin film media with perpendicular c-axis orientation and small grain size  

E-Print Network [OSTI]

Barium ferrite thin film media with perpendicular c-axis orientation and small grain size Zailong, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 Barium ferrite thin films with perpendicular c conditions. The c-axis orientation of barium ferrite thin films is most sensitive to the oxygen partial

Laughlin, David E.

34

Effect of magnetic field applied during secondary annealing on texture and grain size of silicon steel  

E-Print Network [OSTI]

affects the performance of electrical machines making the control of grain size to be an important issue magnetic material of prime importance in the electrical industry, which con- sumes hundreds of thousands plant gen- erators and electric motors. The magnetic behav- iour of this material is mainly controlled

Garmestani, Hamid

35

Estimating quality factor and mean grain size of sediments from high-resolution marine seismic data  

E-Print Network [OSTI]

30 m of unconsolidated marine sediments. Our spectral-ratio technique does not require assumptions-resolution seismic-reflection data, and shows how such estimates can be related to mean grain sizes of unconsolidated for intrinsic atten- uation in saturated, unconsolidated marine sediments. Biot-Stoll Biot, 1956a, 1956b; Stoll

National Oceanography Centre Southampton

36

Particle size distribution of indoor aerosol sources  

SciTech Connect (OSTI)

As concern about Indoor Air Quality (IAQ) has grown in recent years, it has become necessary to determine the nature of particles produced by different indoor aerosol sources and the typical concentration that these sources tend to produce. These data are important in predicting the dose of particles to people exposed to these sources and it will also enable us to take effective mitigation procedures. Further, it will also help in designing appropriate air cleaners. A new state of the art technique, DMPS (Differential Mobility Particle Sizer) System is used to determine the particle size distributions of a number of sources. This system employs the electrical mobility characteristics of these particles and is very effective in the 0.01--1.0 {mu}m size range. A modified system that can measure particle sizes in the lower size range down to 3 nm was also used. Experimental results for various aerosol sources is presented in the ensuing chapters. 37 refs., 20 figs., 2 tabs.

Shah, K.B.

1990-10-24T23:59:59.000Z

37

On Techniques to Characterize and Correlate Grain Size, Grain Boundary Orientation and the Strength of the SiC Layer of TRISO Coated Particles: A Preliminary Study  

SciTech Connect (OSTI)

The mechanical properties of the silicon carbide (SiC) layer of the TRi-ISOtropic (TRISO) coated particle (CP) for high temperature gas reactors (HTGR) are performance parameters that have not yet been standardized by the international HTR community. Presented in this paper are the results of characterizing coated particles to reveal the effect of annealing temperature (1000 to 2100C) on the strength and grain size of unirradiated coated particles. This work was further expanded to include possible relationships between the grain size and strength values. The comparative results of two strength measurement techniques and grain size measured by the Lineal intercept method are included. Preliminary grain boundary characterization results determined by electron backscatter diffraction (EBSD) are included. These results are also important for future fission product transport studies, as grain boundary diffusion is identified as a possible mechanism by which 110mAg, one of the fission activation products, might be released through intact SiC layers. Temperature is a parameter known to influence the grain size of SiC and therefore it is important to investigate the effect of high temperature annealing on the SiC grain size. Recommendations and future work will also be briefly discussed.

I.J.van Rooyen; J.L. Dunzik Gougar; T. Trowbridge; Philip M van Rooyen

2012-10-01T23:59:59.000Z

38

Method to grow carbon thin films consisting entirely of diamond grains 3-5 nm in size and high-energy grain boundaries  

DOE Patents [OSTI]

An ultrananocrystalline diamond (UNCD) having an average grain size between 3 and 5 nanometers (nm) with not more than about 8% by volume diamond having an average grain size larger than 10 nm. A method of manufacturing UNCD film is also disclosed in which a vapor of acetylene and hydrogen in an inert gas other than He wherein the volume ratio of acetylene to hydrogen is greater than 0.35 and less than 0.85, with the balance being an inert gas, is subjected to a suitable amount of energy to fragment at least some of the acetylene to form a UNCD film having an average grain size of 3 to 5 nm with not more than about 8% by volume diamond having an average grain size larger than 10 nm.

Carlisle, John A.; Auciello, Orlando; Birrell, James

2006-10-31T23:59:59.000Z

39

The evolution of texture and grain size during annealing of nanocrystalline Ni-45% Fe electrodeposits  

SciTech Connect (OSTI)

The study of thermal stability of nanocrystalline materials is of great importance for the general assessment of potential technological applications. This is especially true for nanocrystals obtained by electrodeposition. A high electrode polarization, usually used during electrodeposition to reduce grain size, produces materials that are not in a state of equilibrium. This results in a large driving force for grain growth at elevated temperatures. The purpose of this investigation is to examine the thermal stability of nanocrystalline Ni-45 wt.% Fe alloy produced by electrodeposition. Of particular interest is the evolution of texture during annealing and the change of hardness.

Czerwinski, F.; Li, H.; Megret, M.; Szpunar, J.A. [McGill Univ., Montreal, Quebec (Canada). Dept. of Metallurgical Engineering] [McGill Univ., Montreal, Quebec (Canada). Dept. of Metallurgical Engineering; Clark, D.G.; Erb, U. [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Materials and Metallurgical Engineering] [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Materials and Metallurgical Engineering

1997-12-15T23:59:59.000Z

40

Downstream patterns of bed material grain size in a large, lowland alluvial river subject to low sediment supply  

E-Print Network [OSTI]

Downstream patterns of bed material grain size in a large, lowland alluvial river subject to low. The data also show that tributaries have a minor impact on main stem downstream fining due to basin shape of downstream fining. Citation: Singer, M. B. (2008), Downstream patterns of bed material grain size in a large

California at Santa Barbara, University of

Note: This page contains sample records for the topic "grain 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

Effect of sediment pulse grain size on sediment transport rates and bed mobility in gravel bed rivers  

E-Print Network [OSTI]

Effect of sediment pulse grain size on sediment transport rates and bed mobility in gravel bed] Sediment supply to gravel bed river channels often takes the form of episodic sediment pulses, and there is considerable interest in introducing sediment pulses in stream restorations to alter bed surface grain size

Venditti, Jeremy G.

42

Effect of microstructure, grain size, and rare earth doping on the electrorheological performance of nanosized particle materials  

E-Print Network [OSTI]

and grain sizes were prepared by doping TiO2 or ZrO2 with rare earth (RE) elements, and by changingEffect of microstructure, grain size, and rare earth doping on the electrorheological performance-Hua Zhang,c Shu-Mei Chen,d Rui-Li Huange and Song Gaoa a State Key Laboratory of Rare Earth Materials

Gao, Song

43

Parameterizing Size Distribution in Ice Clouds  

SciTech Connect (OSTI)

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 m) 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 m), 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 m wavelength relative to 11 m wavelength due to the process of wave resonance or photon tunneling more active at 12 m. This makes the 12/11 m absorption optical depth ratio (or equivalently the 12/11 m 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

44

Pore size distribution and accessible pore size distribution in bituminous coals  

SciTech Connect (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

45

The equilibrium crystal shape of strontium titanate and its relationship to the grain boundary plane distribution  

E-Print Network [OSTI]

1 The equilibrium crystal shape of strontium titanate and its relationship to the grain crystal shape (ECS) of a model system, strontium titanate, is compared with the grain boundary plane distribution (GBPD) as a function of temperature. Strontium titanate has a pronounced surface energy anisotropy

Rohrer, Gregory S.

46

Spectral Energy Distributions of T Tauri and Herbig Ae Disks: Grain Mineralogy, Parameter Dependences, and Comparison with ISO LWS Observations  

E-Print Network [OSTI]

We improve upon the radiative, hydrostatic equilibrium models of passive circumstellar disks constructed by Chiang & Goldreich (1997). New features include (1) account for a range of particle sizes, (2) employment of laboratory-based optical constants of representative grain materials, and (3) numerical solution of the equations of radiative and hydrostatic equilibrium within the original 2-layer (disk surface + disk interior) approximation. We explore how the spectral energy distribution (SED) of a face-on disk depends on grain size distributions, disk geometries and surface densities, and stellar photospheric temperatures. Observed SEDs of 3 Herbig Ae and 2 T Tauri stars, including spectra from the Long Wavelength Spectrometer (LWS) aboard the Infrared Space Observatory (ISO), are fitted with our models. Silicate emission bands from optically thin, superheated disk surface layers appear in nearly all systems. Water ice emission bands appear in LWS spectra of 2 of the coolest stars. Infrared excesses in several sources are consistent with vertical settling of photospheric grains. While this work furnishes further evidence that passive reprocessing of starlight by flared disks adequately explains the origin of infrared-to-millimeter wavelength excesses of young stars, we emphasize how the SED alone does not provide sufficient information to constrain particle sizes and disk masses uniquely.

E. I. Chiang; M. K. Joung; M. J. Creech-Eakman; C. Qi; J. E. Kessler; G. A. Blake; E. F. van Dishoeck

2000-09-26T23:59:59.000Z

47

activity size distributions: Topics by E-print Network  

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

of nutrients increased Mazumder, Asit 33 A COMPOSITE SOURCE MODEL WITH FRACTAL SUBEVENT SIZE DISTRIBUTION Geosciences Websites Summary: A COMPOSITE SOURCE MODEL WITH FRACTAL...

48

activity size distribution: Topics by E-print Network  

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

of nutrients increased Mazumder, Asit 33 A COMPOSITE SOURCE MODEL WITH FRACTAL SUBEVENT SIZE DISTRIBUTION Geosciences Websites Summary: A COMPOSITE SOURCE MODEL WITH FRACTAL...

49

ARM - Measurement - Aerosol particle size distribution  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Related InformationAcid RainTheimage ARM Dataparticle size

50

Subcritical Creep Compaction of Quartz Sand at Diagenetic Conditions: Effects of Water and Grain Size  

E-Print Network [OSTI]

1 Subcritical Creep Compaction of Quartz Sand at Diagenetic Conditions: Effects of Water and Grain growth. Creep rates are explained by subcritical crack growth, as governed by water-silicate reactions through subcritical cracking and grain rearrangement of medium- grained, porous, wet quartz sands can

Chester, Frederick M.

51

Dust size distribution and concentrations with cottonseed oil mills  

E-Print Network [OSTI]

DUST SIZE DISTRIBUTION AND CONCENTRATIONS WITHIN COTTONSEED OIL MILLS A Thesis by LEE ROY WIEDERHOLD, JR. / I Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE August 1976 Major Subject: Aqricultural Engineering DUST SIZE DISTRIBUTION AND CONCENTRATIONS WITHIN COTTONSEED OIL MILLS A Thesis by LEE ROY WIEDERHOLD, JR. Approved as to style and content by: Chairman of Committee ~Hd fdp t Member ber...

Wiederhold, Lee Roy

1976-01-01T23:59:59.000Z

52

Modeling the formation and size distribution of fly ash  

SciTech Connect (OSTI)

A set of mathematical models has been developed to predict the size distribution of fly ash particles formed in pulverized coal combustion. The large particle mode of the size distribution, typically centered about 10 to 20 ..mu..m, is predicted by a simple breakup model that is based on the complete coalescence of molten mineral inclusions within fragments of the devolatilized coal char. The ultrafine particle mode, that is typically centered about 0.1 to 0.2 ..mu..m, is modeled in terms of ash volatilization, nucleation, and coagulation. Silica and alumina are reduced to volatile suboxides through reactions at the char surface. The volatile suboxides are transported from the char surface where they are oxidized back to the stable oxides in the bulk gas, and then nucleated in accordance with homogeneous nucleation theory. The ultrafine nuclei coagulate in accordance with Brownian coagulation theory. The predicted particle size spectra have been compared to measured size distributions from a pilot-scale combustor and a full-scale utility boiler. Considering the disproportionate loss of coarse particles in the pilot-scale unit, the agreement between the predicted and measured size distributions was considered reasonably good. Both the predicted ultrafine and large particle modes agreed reasonably well with the measured particle size distribution for the full scale boiler. The validated computer models were used to study the effect of changes in the coal ash content, coal particle size, and the combustion flame temperature.

Dahlin, R.S.

1985-01-01T23:59:59.000Z

53

Atomically flat La-silicate/Si interface using tungsten carbide gate electrode with nano-sized grain  

SciTech Connect (OSTI)

Interface properties of La-silicate gate dielectrics on Si substrates with W or nano-sized grain W{sub 2}C gate electrodes have been investigated. A low interface state density of 2.5??10{sup 11}?cm{sup ?2}/eV has been achieved with W{sub 2}C gate electrodes, which is one third of those with W gate electrode. An interface roughness of 0.33?nm with spatial frequency comparable to the grain size of W gate electrode has been observed. Besides, an atomically flat interface of 0.12?nm has been obtained with W{sub 2}C gate electrode. The origin of flat interface may be attributed to the elimination of inhomogeneous stress by grains in metal electrode.

Tuokedaerhan, K.; Natori, K.; Iwai, H. [Frontier Research Center, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Kakushima, K., E-mail: kakushima@ep.titech.ac.jp; Kataoka, Y.; Nishiyama, A.; Sugii, N.; Wakabayashi, H.; Tsutsui, K. [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

2014-01-13T23:59:59.000Z

54

Sedimentation of algae: relationships with biomass and size distribution1  

E-Print Network [OSTI]

Sedimentation of algae: relationships with biomass and size distribution1 Isabelle Larocque, A distribution of epilimnetic algae on patterns of algal sedimentation was determined in lake enclosures under the mean length of algae in fish-free enclosures and reduced the mean length in the enclosures to which

Mazumder, Asit

55

Evolution of particle size distribution after the CFFF secondary combustor  

SciTech Connect (OSTI)

Particle size distribution after the CFFF secondary combustor is studied in this paper. As an important mechanism of particle collision, thermophoresis is briefly discussed in this paper and the thermophoretic velocity is given. The temperature gradient that causes the thermophoretic force is established between high and low temperature particles in the flow, which results from convection and radiation heat balance between particles and wall. Particle temperature with respect to their sizes is obtained. Mechanism of agglomeration and collection efficiency of fine particles is presented. Finally, at the inlet of the ESP, theoretical particle size distribution is compared with the experimental measurements at CFFF.

Yang, Dujiu; Crawford, L.W.

1993-06-01T23:59:59.000Z

56

Evolution of particle size distribution after the CFFF secondary combustor  

SciTech Connect (OSTI)

Particle size distribution after the CFFF secondary combustor is studied in this paper. As an important mechanism of particle collision, thermophoresis is briefly discussed in this paper and the thermophoretic velocity is given. The temperature gradient that causes the thermophoretic force is established between high and low temperature particles in the flow, which results from convection and radiation heat balance between particles and wall. Particle temperature with respect to their sizes is obtained. Mechanism of agglomeration and collection efficiency of fine particles is presented. Finally, at the inlet of the ESP, theoretical particle size distribution is compared with the experimental measurements at CFFF.

Yang, Dujiu; Crawford, L.W.

1993-01-01T23:59:59.000Z

57

Effect of Y-211 particle size on the growth of single grain YBaCuO bulk superconductors  

E-Print Network [OSTI]

The engineering of fine Y2Ba1Cu1O5 (Y-211) inclusions of average particle size 1?2 ?m within the continuous, superconducting YBa2Cu3O7?? (Y-123) phase matrix of single-grain, bulk high temperature YBaCuO (YBCO) superconductors is fundamental...

Thoma, Max; Shi, Yunhua; Dennis, Tony; Durrell, John; Cardwell, David

2014-12-01T23:59:59.000Z

58

NEAMS FPL M2 Milestone Report: Development of a UO? Grain Size Model using Multicale Modeling and Simulation  

SciTech Connect (OSTI)

This report summarizes development work funded by the Nuclear Energy Advanced Modeling Simulation program's Fuels Product Line (FPL) to develop a mechanistic model for the average grain size in UO? fuel. The model is developed using a multiscale modeling and simulation approach involving atomistic simulations, as well as mesoscale simulations using INL's MARMOT code.

Tonks, Michael R. [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Zhang, Yongfeng [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Bai, Xianming [Idaho National Laboratory (INL), Idaho Falls, ID (United States)

2014-06-01T23:59:59.000Z

59

CHP and CHPsim: A Language and Simulator for Fine-Grain Distributed Computation  

E-Print Network [OSTI]

1 CHP and CHPsim: A Language and Simulator for Fine-Grain Distributed Computation Alain J. Martin Abstract--This paper describes a complete and stable version of CHP and the simulator CHPsim. CHP partial versions of the language are already widely used, but CHP has never been presented as a complete

Martin, Alain

60

Relative grain boundary area and energy distributions in nickel Jia Li, Shen J. Dillon 1  

E-Print Network [OSTI]

Relative grain boundary area and energy distributions in nickel Jia Li, Shen J. Dillon 1 , Gregory boundary energies and areas are inversely correlated. 2009 Acta Materialia Inc. Published by Elsevier Ltd and focused ion beam serial sectioning. These data have been used to determine the relative areas of different

Rohrer, Gregory S.

Note: This page contains sample records for the topic "grain 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

Spatial grain size sorting in eolian ripples and estimation of wind conditions on planetary surfaces  

E-Print Network [OSTI]

measurements from White Sands National Monument, New Mexico, show that such coarse-grained ripples form by the different transport modes of coarse- and fine-grain fractions. On the basis of our field study, and simple) Thermal Emission Spectrom- eter (TES), which was interpreted to reflect iron precipita- tion in surficial

Grotzinger, John P.

62

From flux to dust mass: Does the grain-temperature distribution matter for estimates of cold dust masses in supernova remnants?  

E-Print Network [OSTI]

The amount of dust estimated from infrared to sub-millimetre (submm) observations strongly depends on assumptions of different grain sizes, compositions and optical properties. Here we use a simple model of thermal emission from cold silicate/carbon dust at a range of dust grain temperatures and fit the spectral energy distribution (SED) of the Crab Nebula as a test. This can lower the derived dust mass for the Crab by ~50% and 30-40% for astronomical silicates and amorphous carbon grains compared to recently published values (0.25M_sun -> 0.12M_sun and 0.12M_sun -> 0.072M_sun, respectively), but the implied dust mass can also increase by as much as almost a factor of six (0.25M_sun -> 1.14M_sun and 0.12M_sun -> 0.71M_sun) depending on assumptions regarding the sizes/temperatures of the coldest grains. The latter values are clearly unrealistic due to the expected metal budget, though. Furthermore, we show by a simple numerical experiment that if a cold-dust component does have a grain-temperature distribution...

Mattsson, Lars; Andersen, Anja C; Matsuura, Mikako

2015-01-01T23:59:59.000Z

63

Lognormal Size Distribution Theory for Deposition of Polydisperse Aerosol Particles  

SciTech Connect (OSTI)

The moments method of the lognormal size distribution theory was applied to the deposition equation of a radioactive aerosol within a liquid-metal fast breeder reactor for analysis of postulated accidents. The deposition coefficient of Crump and Seinfeld was utilized to represent the Brownian and turbulent diffusions and the gravitational sedimentation. The deposition equation was converted into a set of three ordinary differential equations. This approach takes the view point that the size distribution of an aerosol is represented by a time-dependent lognormal size distribution function during the deposition process. Numerical calculations have been performed, and the results were found to be in good agreement with the exact solution. The derived model for aerosol deposition is convenient to use in a numerical general dynamic equation solution routine based on the moments method, where nucleation, condensation, coagulation, and deposition need to be solved simultaneously.

Park, S.H.; Lee, K.W. [Kwangju Institute of Science and Technology (Korea, Republic of)

2000-07-15T23:59:59.000Z

64

The relative grain boundary area and energy distributions in a ferritic steel determined from three-dimensional electron  

E-Print Network [OSTI]

The relative grain boundary area and energy distributions in a ferritic steel determined from three The relative grain boundary area and energy distributions of a ferritic steel were characterized as a function planes with the (111) orientation had the minimum energy and the largest relative areas. The most

Rohrer, Gregory S.

65

Selected room temperature magnetic parameters as a function of mineralogy, concentration and grain size  

E-Print Network [OSTI]

Selected room temperature magnetic parameters as a function of mineralogy, concentration and grain literature. The aim was to propose the most effective methods for assessing mineralogy, concentration and domain state within environmental magnetic studies. Establishing the magnetic mineralogy is essential

Utrecht, Universiteit

66

Effects of dust size distribution on dust negative ion acoustic solitary waves in a magnetized dusty plasma  

SciTech Connect (OSTI)

Dust negative ion acoustic solitary waves in a magnetized multi-ion dusty plasma containing hot isothermal electron, ions (light positive ions and heavy negative ions) and extremely massive charge fluctuating dust grains are investigated by employing the reductive perturbation method. How the dust size distribution affect the height and the thickness of the nonlinear solitary wave are given. It is noted that the characteristic of the solitary waves are different with the different dust size distribution. The magnitude of the external magnetic field also affects the solitary wave form.

Ma, Yi-Rong; Qi, Xin; Sun, Jian-An; Duan, Wen-Shan [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China)] [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China); Yang, Lei [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China) [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)

2013-08-15T23:59:59.000Z

67

Multi analysis of the effect of grain size on the dynamic behavior of microalloyed steels  

SciTech Connect (OSTI)

This study presents some aspects of multiscale analysis and modeling of variously structured materials behavior in quasi-static and dynamic loading conditions. The investigation was performed for two different materials of common application: high strength microalloyed steel (HSLA, X65), and as a reference more ductile material, Ti-IF steel. The MaxStrain technique and one pass hot rolling processes were used to produce ultrafine-grained and coarse-grained materials. The efficiency and inhomogeneity of microstructure refinement were examined because of their important role in work hardening and the initiation and growth of fracture under tensile stresses. It is shown that the combination of microstructures characterized by their different features contributes to the dynamic behavior and final properties of the product. In particular, the role of solute segregation at grain boundaries as well as precipitation of carbonitrides in coarse and ultrafine-grained structures is assessed. The predicted mechanical response of ultrafine-grained structures, using modified KHL model is in reasonable agreement with the experiments. This is a result of proper representation of the role of dislocation structure and the grain boundary and their multiscale effects included in this model.

Zurek, Anna K [Los Alamos National Laboratory; Muszka, K [AGH; Majta, J [AGH; Wielgus, M [AGH

2009-01-01T23:59:59.000Z

68

Loss Reduction of Power Distribution Network Using Optimum Size and Location of Distributed  

E-Print Network [OSTI]

Generation Adnan Anwar, Student Member, IEEE, and H. R. Pota, Member, IEEE Abstract--Distributed generation be reduced significantly. Index Terms--Distributed generation, Optimum size, Optimum location, Power loss directly to utility distribution system. The insulation level of the machines may not synchronize

Pota, Himanshu Roy

69

Particle size of reconstituted sorghum grain as related to its digestibility and to cattle performance  

E-Print Network [OSTI]

TREATMENTS OF SORGHUM GRAIN AFTER VARIOUS INCUBATION PERIODS . 27 RELATIVE IN VITRO GAS PRODUCTION EXPRESSED AS A PERCENT OF D-G CONTROL . CHEMICAL COMPOSITION OF FOUR FEED MIXTURES FED DURING DIGESTION EXPERIMENT 28 30 AVERAGE COEFFICIENTS... to 13 ion ouantities for use in this study. }hi grain was submitted to our trcatm nts as foils!!s: Dry-grourd {D-G) Ground-reconstituted (G-R) Ground-reconstituted-ground (G-R-G) Reconstiiutcd-ground (R-G) the recon"tiiutcd treatments consisted...

Berry, Larry Don

1970-01-01T23:59:59.000Z

70

The Size Distribution of Superbubbles in the Interstellar Medium  

E-Print Network [OSTI]

We use the standard, adiabatic shell evolution to predict the size distribution N(R) for populations of SN-driven superbubbles in a uniform ISM. We derive N(R) for simple cases of superbubble creation rate and mechanical luminosity function. We then compare our predictions for N(R) with the largely complete HI hole catalogue for the SMC, with a view toward the global structure of the ISM in that galaxy. We also present a preliminary derivation for N(v), the distribution of shell expansion velocities.

M. S. Oey; C. J. Clarke

1998-03-06T23:59:59.000Z

71

Distributive analysis of rural land size and price relationships  

E-Print Network [OSTI]

manuscript. :ABLE OF CONTENTS Chapter Page I. IN:RODUCTION The Problem Objectives of the Study 1 2 II. PREVIOUS RESEARCH U. S. Aggregate Studies Texas and Regional Studies 5 6 III. ECONOMIC THEORY AND LAND VALUES IV. HYPOTHESES AND METHODOLOGY... 12 Market Movements Frictional Adjustments Economies of Size 12 1". 13 Factors of Consideration Market Division Methodology Bases Percentages Blocks Groups Appreciation Market Distribution 15 17 18 19 20 20 23 24 The Models...

Rothe, Robert Joseph

2012-06-07T23:59:59.000Z

72

Aerosol size distribution evolution in large area fire plumes  

SciTech Connect (OSTI)

Large fires are significant seasonal contributors to western visibility reduction. We have found that the relative concentration of supermicron size particles (assumed to be a mixture of mechanically generated particles by high winds associated with large fires and low density chain aggregates from coagulation in the fire) and high turbulence in fire plumes can radically change the aerosol sizes in the fire plume. This is especially important for aerosols with high visibility reduction and long range transport potential. This calculation was done with a 10 level one dimensional model with parameterized vertical and horizontal diffusion, sedimentation and coagulation. The optical effects of the evolving concentration and size distributions were modeled using Mie scattering and absorption assumptions.

Porch, W.M.; Penner, J.E.

1986-09-01T23:59:59.000Z

73

Distribution Effectiveness and Impacts on Equipment Sizing for Residential Thermal Distribution Systems  

E-Print Network [OSTI]

1 LBNL-43724 Distribution Effectiveness and Impacts on Equipment Sizing for Residential Thermal Distribution Systems Walker, I., Sherman, M., and Siegel, J. Environmental Energy Technologies Division Energy .................................................................................................................. 14 Figure 1. Simulations of Pulldowns from 3:00 p.m. on a Sacramento Design Day

74

Mineralogy and particle size of bed sediments 173 Chapter 7 -Quantitative Mineralogy and Particle-Size Distribution  

E-Print Network [OSTI]

Mineralogy and particle size of bed sediments 173 Chapter 7 - Quantitative Mineralogy and Particle to assess particle-size distribution and mineralogical composition. Changes in particle- size distribution-ray diffraction, and their quantitative mineralogy was determined with a recently-developed computer program

75

Study on grain boundary character and strain distribution of intergranular cracking in the CGHAZ of T23 steel  

SciTech Connect (OSTI)

Intergranular reheat cracking in the coarse-grained heat-affected zone of T23 steel was produced by strain to fracture tests on a Gleeble 3500 thermalmechanical simulator. Then the grain boundary character, as well as the strain distribution after reheat crack propagation, was studied by electron backscatter diffraction technique. The results showed that incoherent ?3 boundaries were seldom found on the prior austenite grain boundaries. Therefore, only the type of random high-angle boundaries played a crucial role in the intergranular cracking. Microstructurally cavities and small cracks were preferentially initiated from high-angle grain boundaries. Low-angle grain boundaries and high-angle ones with misorientation angles less than 15 were more resistant to the cracking. More importantly, the fraction of high-angle grain boundaries increased with the plastic strain induced by both temperature gradient and stress in the coarse-grained heat-affected zone, which contributed to the crack initiation and propagation. Furthermore, the strain distributions in the vicinity of cavities and cracks revealed the accommodation processes of plastic deformation during stress relaxation. It also reflected the strength differences between grain interior and grain boundary at different heat-treated temperatures, which had a large influence on the cracking mechanism. - Highlights: The coincidence site lattice boundaries play little role in the reheat cracking. Cavity and crack occur at high-angle grain boundaries rather than low-angle ones. The strain leads low-angle grain boundaries to transform to high-angle ones. Strain distribution differs for cavity and crack zones at different temperatures.

Jin, Y.J.; Lu, H., E-mail: shweld@sjtu.edu.cn; Yu, C.; Xu, J.J.

2013-10-15T23:59:59.000Z

76

EFFECTS OF MINERALOGY, GRAIN SIZE, AND SOLUTION COMPOSITION ON LITHIUM SORPTION TO SATURATED ALLUVIUM SOUTH OF YUCCA MOUNTAIN, NEVADA  

SciTech Connect (OSTI)

Lithium is used frequently as a surrogate for cationic radionuclides such as NpO{sub 2}{sup +} in field and laboratory settings. Current plans include the use of Li{sup +} as a reactive tracer in field tracer testing in the saturated alluvium south of Yucca Mountain, NV, site of a potential high-level nuclear waste. Characterization of the alluvial material for grain size, mineralogy, cation exchange capacity (CEC), and surface area yields data that is compared with lithium batch sorption as a first step in inferring radionuclide transport behavior. This research will be used to help assess performance of the potential repository.

E. SULLIVAN; P. REIMUS; ET AL

2001-05-01T23:59:59.000Z

77

Sliding friction in electrodeposited nanocrystalline Ni Alloys : transitional behavior associated with grain size, sliding speed, and contact stress.  

SciTech Connect (OSTI)

Metallic materials in sliding contact typically undergo dislocation-mediated plasticity, which results in stick-slip frictional behavior associated with high coefficients of friction ({mu} > 0.8). Our recent work on two electroplated nanocrystalline Ni alloys reveal that under combined conditions of low stress and low sliding velocity, these metals have very low friction ({mu} < 0.3). The observed frictional behavior is consistent with the transition from dislocation-mediated plasticity to an alternative mechanism such as grain boundary sliding. Focused ion beam cross-sections viewed in the TEM reveal the formation of a subsurface tribological bilayer at the contact surface, where the parent nanocrystalline material has evolved in structure to accommodate the frictional contact. Grain growth at a critical distance below the contact surface appears to promote a shear-accomodation layer. We will discuss these results in the context of a grain-size dependent transition from conventional microcrystalline wear behavior to this unusual wear behavior in nanocrystalline FCC metals.

Prasad, Somuri V.; Battaile, Corbett Chandler; Boyce, Brad Lee; Kotula, Paul Gabriel; Padilla, Henry A.

2010-10-01T23:59:59.000Z

78

Method for measuring the size distribution of airborne rhinovirus  

SciTech Connect (OSTI)

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.

Russell, M.L.; Goth-Goldstein, R.; Apte, M.G.; Fisk, W.J.

2002-01-01T23:59:59.000Z

79

E-Print Network 3.0 - adsorbent grain size Sample Search Results  

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

error size is about 15-20% for lower ad- sorbed mass region, B10... orientations of trains versus loops and tails: the adsorbed ... Source: Granick, Steve - Departments of...

80

The Superbubble Size Distribution in the Interstellar Medium of Galaxies  

E-Print Network [OSTI]

We use the standard, adiabatic shell evolution to predict the size distribution N(R) for populations of OB superbubbles in a uniform ISM. We derive N(R) for simple cases of superbubble creation rate and mechanical luminosity function (MLF). For R R_e it is dominated by growing objects. We also briefly investigate N(R) resulting from momentum-conserving shell evolution. We predict a peak in N(R) corresponding to individual SNRs. To estimate the MLF, we also examine evolutionary effects on the HII region luminosity function (HII LF), finding that for nebular luminosity fading as a power law in time, there is a minimum observed slope for the HII LFs. Comparison with the largely complete HI hole catalog for the SMC shows surprising agreement in the predicted and observed slope of N(R), suggesting that no other fundamental process is needed to explain the size distribution of shells in the SMC. Further comparison with largely incomplete HI data for M31, M33, and Holmberg II is also encouraging. We present expressions for the ISM porosity parameters, and estimate that they are substantially <1 for all of the galaxies except Holmberg II. Most of these galaxies therefore may not be strongly dominated by a hot interstellar component. However, porosity results for the Galaxy remain inconclusive.

M. S. Oey; C. J. Clarke

1997-03-17T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

JOURNAL DE PHYSIQUE Colloque C I, fuppl&nent au no 2-3, Tome 32, Fkvrier-Mars 1971,page C 1 -383 THE RELATIONSHIP OF DOMAIN SPACING, GRAIN SIZE,  

E-Print Network [OSTI]

THE RELATIONSHIP OF DOMAIN SPACING, GRAIN SIZE, SHEET THICKNESS AND POWER LOSS K. J. OVERSHOTT, Wolfson Centre- , - - bowing was found to occur. The total power loss in the same grains has been measured at various flux) at a smaller grain length. - 1. Introduction. - The total power loss in grain- oriented siliconiron is greater

Paris-Sud XI, Universit de

82

Effect of Engine-Out NOx Control Strategies on PM Size Distribution...  

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

Engine-Out NOx Control Strategies on PM Size Distribution in Heavy-Duty Diesel Engines Developed for 2010 Effect of Engine-Out NOx Control Strategies on PM Size Distribution in...

83

Slant visual range from drop-size distribution  

E-Print Network [OSTI]

. 1796 x 10 -5 6. 4781 x 10 -5 6. 8817 x 10 7. 4708 x 10 -5 6. 4Z3Z x 10 3. 4338 x 10 -5 l. 8538 x 10 9. 1Z32 x 10 5. 1436 x 10 3. 1019 x 10 3. 3120 x 10 -6 3. 6597 x 10 6. Z636 x 10 4. 2730 x 10 3. 8357 x 10 1 4. OZ10 x 10 1 4. Z715 x 10...'laj or Subject: Mete orol oqy SLANT VISUAL RANGE FROM DROP-SIZE DISTRIBUTION A Thesis by EDWIN STANLEY ARRANCE Approved as to style and content by: Dr. Vance E. Moyer; (Chairman of Committee) Dr. Geor L. Huebner, Jr. (Member) Dr. Glen N. Williams...

Arrance, Edwin Stanley

2012-06-07T23:59:59.000Z

84

Measurements of Gas Bubble Size Distributions in Flowing Liquid Mercury  

SciTech Connect (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

85

Effect of oxidizer on grain size and low temperature DC electrical conductivity of tin oxide nanomaterial synthesized by gel combustion method  

SciTech Connect (OSTI)

Nanocrystalline Tin oxide material with different grain size was synthesized using gel combustion method by varying the fuel (C{sub 6}H{sub 8}O{sub 7}) to oxidizer (HNO{sub 3}) molar ratio by keeping the amount of fuel as constant. The prepared samples were characterized by using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Analysis X-ray Spectroscopy (EDAX). The effect of fuel to oxidizer molar ratio in the gel combustion method was investigated by inspecting the grain size of nano SnO{sub 2} powder. The grain size was found to be reduced with the amount of oxidizer increases from 0 to 6 moles in the step of 2. The X-ray diffraction patterns of the calcined product showed the formation of high purity tetragonal tin (IV) oxide with the grain size in the range of 12 to 31 nm which was calculated by Scherer's formula. Molar ratio and temperature dependence of DC electrical conductivity of SnO{sub 2} nanomaterial was studied using Keithley source meter. DC electrical conductivity of SnO{sub 2} nanomaterial increases with the temperature from 80K to 300K. From the study it was observed that the DC electrical conductivity of SnO{sub 2} nanomaterial decreases with the grain size at constant temperature.

Rajeeva, M. P., E-mail: jayanna60@gmail.com; Jayanna, H. S., E-mail: jayanna60@gmail.com; Ashok, R. L.; Naveen, C. S. [Department of P.G. Studies and Research in Physics, Kuvempu University, Jnanasahyadri, Shankarghatta, Shimoga- 577451, Karnataka (India); Bothla, V. Prasad [Department of Physics, Indian Institute of Science, Bangalore-560012 (India)

2014-04-24T23:59:59.000Z

86

Fine scale modeling of wintertime aerosol mass, number, and size distributions in central California  

E-Print Network [OSTI]

Fine scale modeling of wintertime aerosol mass, number, and size distributions in central with the observed PM number and size distributions (with an NMB of -13.9%), indicating the importance of coagulation scale modeling of wintertime aerosol mass, number, and size distributions in central California, J

Jacobson, Mark

87

The equilibrium crystal shape of strontium titanate and its relationship to the grain boundary plane distribution  

E-Print Network [OSTI]

The equilibrium crystal shape of strontium titanate and its relationship to the grain boundary system, strontium titanate, is compared with the grain boundary plane dis- tribution (GBPD) as a function of temperature. Strontium titanate has a pronounced surface energy anisotropy and a grain growth anomaly

Rohrer, Gregory S.

88

Fidelity of Analytic Drop Size Distributions in Drizzling Stratiform Clouds Based on Large-Eddy Simulations  

E-Print Network [OSTI]

Cloud microphysical parameterizations and retrievals rely heavily on knowledge of the shape of drop size distributions (DSDs). Many investigations assume that DSDs in the entire or partial drop size range may be approximated ...

Kogan, Yefim L.; Kogan, Zena N.; Mechem, David B.

2009-08-01T23:59:59.000Z

89

Size distribution and chemical composition of aerosol particles in the free troposphere over Japan: Aircraft measurements  

SciTech Connect (OSTI)

Aircraft measurements of number-, mass- and volume-size distributions of aerosols and concentration of sulfate, nitrate and others contained in particulate matter were made in the free troposphere over Japan in 1991-1994. Number-size distribution frequently shows a peak in the area of a diameter of D {ge} 1 {mu}m in the free troposphere during observational periods. A few peaks are identified in the volume-size distribution as estimated on the basis of number-size distribution having single mode in a coarse range. Mass-size distribution frequently indicate enhancement in the coarse size range. This feature of the distribution is more frequent in those measurements made at 4.42 km than those at 2.29 km. On the basis of a backward trajectory analysis of the air mass containing those particles, soil particles originating from the Asian continent affect the features found in the size distributions as well as and vertical change in those size distributions. Particulate sulfate concentration in the free troposphere suggested that chemical transformation of particles with D {ge} 1 {mu}m advanced during long range transport of the particle possibly through coagulation of sulfate particles on coarse size particles such as Asian dust particles, adsorption of gaseous sulfate. Those measurements provide useful data et to discuss global geochemical cycle and radiative forcing of particles originated from the Asian continent.

Iwasaka, Y.; Mori, I.; Mastunga, K. [Nagoya Univ. (Japan)

1996-12-31T23:59:59.000Z

90

Size distribution of recruited alveolar volumes in airway reopening  

E-Print Network [OSTI]

during the reopening process can influence the distribution of recruited alveolar volumes and, hence, gas distribution of recruited alveolar volumes that become available for gas exchange during inflation from important quantity is the amount of alveolar volume available for gas exchange. This alveolar volume

Alencar, Adriano Mesquita

91

Optimum Allocation and Sizing of DG Unit for Efficiency Enhancement of Distribution System  

E-Print Network [OSTI]

of appropriate size and location of DG reduces total power loss in a distribution system significantly and hence, Power loss reduction, Sensitivity analysis. I. INTRODUCTION Distributed Generation (DG) has gained its size and inappropriate allocation of generation may lead to higher power loss than when there is no DG

Pota, Himanshu Roy

92

Determination of pore-size distribution in low-dielectric thin films D. W. Gidleya)  

E-Print Network [OSTI]

-size distribution on pore shape/dimensionality and sample temperature is predicted using a simple quantum mechanicalDetermination of pore-size distribution in low-dielectric thin films D. W. Gidleya) and W. E. Frieze Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 T. L. Dull, J. Sun, and A

Gidley, David

93

A fractal-based approach to lake size-distributions David A. Seekell,1  

E-Print Network [OSTI]

A fractal-based approach to lake size-distributions David A. Seekell,1 Michael L. Pace,1 Lars J in regional and global biogeochemical processes. Lakes are fractal but do not always conform to the power law size-distribution typically associated with fractal geographical features. Here, we evaluate

Pace, Michael L.

94

A forward microphysical model to predict the size-distribution parameters of laboratory generated (mimic)  

E-Print Network [OSTI]

A forward microphysical model to predict the size- distribution parameters of laboratory generated Interactions ­ Condensational Growth and Coagulation, Submitted for Indian Aerosol Science and Technology Microphysical Model for the UTLS (FAMMUS) is applied to predict the size-distribution parameters of laboratory

Oxford, University of

95

Size distributions of fly ash using Coulter Multisizer: Use of multiple orifices and fitting to truncated log-normal distributions  

SciTech Connect (OSTI)

Fly ash particles, which are predominantly spherical and glassy, are produced by melting of the mineral inclusions in the coal during combustion. Particle diameters can range from sub-micrometer (micron or {mu}m) to greater than 100 {mu}m. The size distribution of fly ash is needed to determine its role in the radiation transfer process in pulverized coal combustors. The Coulter Multisizer is an useful instrument for sizing powders with a broad size distribution. A single Multisizer orifice can size particles only within a specific size range limited at the lower end to a few percent of orifice diameter by sensitivity and at the upper end by increasing non-linearity of the signal-volume relation. A scheme for combining data obtained using orifices of different diameters is described. The manufacturers state that the smallest particle which can be sized accurately is nominally 2% of the diameter of the orifice. However, it was found that the data for particles less than 4% of the orifice diameter were not reliable. In order to use the smaller orifices, the larger particles have to be removed from the sample. A wet-sieving apparatus, designed for accurate separation of the particles by size, is described. A log-normal distribution function, truncated outside the measurement limits, fits the size distribution data well. Size parameters for fly ashes of six representative US coals are presented.

Ghosal, S.; Ebert, J.L.; Self, S.A.

1991-11-01T23:59:59.000Z

96

Multipass comminution process to produce precision wood particles of uniform size and shape with disrupted grain structure from wood chips  

DOE Patents [OSTI]

A process of comminution of wood chips (C) having a grain direction to produce a mixture of wood particles (P), wherein the wood chips are characterized by an average length dimension (L.sub.C) as measured substantially parallel to the grain, an average width dimension (W.sub.C) as measured normal to L.sub.C and aligned cross grain, and an average height dimension (H.sub.C) as measured normal to W.sub.C and L.sub.C, and wherein the comminution process comprises the step of feeding the wood chips in a direction of travel substantially randomly to the grain direction one or more times through a counter rotating pair of intermeshing arrays of cutting discs (D) arrayed axially perpendicular to the direction of wood chip travel.

Dooley, James H; Lanning, David N

2014-05-27T23:59:59.000Z

97

Size distribution of particle systems analyzed with organic photodetectors  

E-Print Network [OSTI]

As part of a consortium between academic and industry, this PhD work investigates the interest and capabilities of organic photo-sensors (OPS) for the optical characterization of suspensions and two-phase flows. The principle of new optical particle sizing instruments is proposed to characterize particle systems confined in a cylinder glass (standard configuration for Process Analytical Technologies). To evaluate and optimize the performance of these systems, a Monte-Carlo model has been specifically developed. This model accounts for the numerous parameters of the system: laser beam profile, mirrors, lenses, sample cell, particle medium properties (concentration, mean & standard deviation, refractive indices), OPS shape and positions, etc. Light scattering by particles is treated either by using Lorenz-Mie theory, Debye, or a hybrid model (that takes into account the geometrical and physical contributions). For diluted media (single scattering), particle size analysis is based on the inversion of scatter...

Sentis, Matthias

2015-01-01T23:59:59.000Z

98

Comminution process to produce engineered wood particles of uniform size and shape with disrupted grain structure from veneer  

DOE Patents [OSTI]

Comminution process of wood veneer to produce wood particles, by feeding wood veneer in a direction of travel substantially normal to grain through a counter rotating pair of intermeshing arrays of cutting discs arrayed axially perpendicular to the direction of veneer travel, wherein the cutting discs have a uniform thickness (Td), to produce wood particles characterized by a length dimension (L) substantially equal to the Td and aligned substantially parallel to grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) substantially equal to the veneer thickness (Tv) and aligned normal to W and L, wherein the W.times.H dimensions define a pair of substantially parallel end surfaces with end checking between crosscut fibers.

Dooley, James H; Lanning, David N

2013-07-30T23:59:59.000Z

99

THE SIZE DISTRIBUTION OF THE NEPTUNE TROJANS AND THE MISSING INTERMEDIATE-SIZED PLANETESIMALS  

SciTech Connect (OSTI)

We present an ultra-deep survey for Neptune Trojans using the Subaru 8.2 m and Magellan 6.5 m telescopes. The survey reached a 50% detection efficiency in the R band at m{sub R} = 25.7 mag and covered 49 deg{sup 2} of sky. m{sub R} = 25.7 mag corresponds to Neptune Trojans that are about 16 km in radius (assuming an albedo of 0.05). A paucity of smaller Neptune Trojans (radii < 45 km) compared with larger ones was found. The brightest Neptune Trojans appear to follow a steep power-law slope (q = 5 {+-} 1) similar to the brightest objects in the other known stable reservoirs such as the Kuiper Belt, Jupiter Trojans, and main belt asteroids. We find a roll-over for the Neptune Trojans that occurs around a radius of r = 45 {+-} 10 km (m{sub R} = 23.5 {+-} 0.3), which is also very similar to the other stable reservoirs. All the observed stable regions in the solar system show evidence for Missing Intermediate-Sized Planetesimals (MISPs). This indicates a primordial and not collisional origin, which suggests that planetesimal formation proceeded directly from small to large objects. The scarcity of intermediate- and smaller-sized Neptune Trojans may limit them as being a strong source for the short period comets.

Sheppard, Scott S. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Rd. NW, Washington, DC 20015 (United States); Trujillo, Chadwick A., E-mail: sheppard@dtm.ciw.ed [Gemini Observatory, 670 North A'ohoku Place, Hilo, HI 96720 (United States)

2010-11-10T23:59:59.000Z

100

Comminution process to produce precision wood particles of uniform size and shape with disrupted grain structure from wood chips  

DOE Patents [OSTI]

A process of comminution of wood chips (C) having a grain direction to produce a mixture of wood particles (P), wherein the wood chips are characterized by an average length dimension (L.sub.C) as measured substantially parallel to the grain, an average width dimension (W.sub.C) as measured normal to L.sub.C and aligned cross grain, and an average height dimension (H.sub.C) as measured normal to W.sub.C and L.sub.C, and wherein the comminution process comprises the step of feeding the wood chips in a direction of travel substantially randomly to the grain direction through a counter rotating pair of intermeshing arrays of cutting discs (D) arrayed axially perpendicular to the direction of wood chip travel, wherein the cutting discs have a uniform thickness (T.sub.D), and wherein at least one of L.sub.C, W.sub.C, and H.sub.C is greater than T.sub.D.

Dooley, James H; Lanning, David N

2013-08-13T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

Lipid-Protein Interactions Alter Line Tensions and Domain Size Distributions in Lung Surfactant Monolayers  

E-Print Network [OSTI]

The size distribution of domains in phase-separated lung surfactant monolayers influences monolayer viscoelasticity and compressibility which, in turn, influence monolayer collapse and set the compression at which the ...

Dhar, Prajnaparamita

102

Particle size distribution and mineralogy of Brazilian Ferralsols: Significance for the structure and hydraulic properties  

E-Print Network [OSTI]

Particle size distribution and mineralogy of Brazilian Ferralsols: Significance for the structure of the mineralogy on the structure and hydraulic properties of Ferralsols. The Ferralsols (F) studied were selected according to the mineralogy of the

Paris-Sud XI, Universit de

103

The influence of particle-size distribution and moisture levels on the formation of soil hardpans  

E-Print Network [OSTI]

THE INFLUENCE OF PARTICLE-SIZE DISTRIBUTION AND MOISTURE LEVELS ON THE FORMATION OF SOIL HARDPANS A Thesis By HERMAN J. BAUER Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE January, 1963 Major Subject: Soil Physics THE INFLUENCE OF PARTICLE-SIZE DISTRIBUTION AND MOISTURE LEVELS ON THE FORMATION OF SOIL HARDPANS A Thesis By HERMAN J. BAUER Approved as to style and content...

Bauer, Herman John

1963-01-01T23:59:59.000Z

104

ON THE COAGULATION AND SIZE DISTRIBUTION OF PRESSURE CONFINED CORES  

SciTech Connect (OSTI)

Observations of the Pipe Nebula have led to the discovery of dense starless cores. The mass of most cores is too small for their self-gravity to hold them together. Instead, they are thought to be pressure confined. The observed dense cores' mass function (CMF) matches well with the initial mass function of stars in young clusters. Similar CMFs are observed in other star forming regions such as the Aquila Nebula, albeit with some dispersion. The shape of these CMF provides important clues to the competing physical processes which lead to star formation and its feedback on the interstellar media. In this paper, we investigate the dynamical origin of the mass function of starless cores which are confined by a warm, less dense medium. In order to follow the evolution of the CMF, we construct a numerical method to consider the coagulation between the cold cores and their ablation due to Kelvin-Helmholtz instability induced by their relative motion through the warm medium. We are able to reproduce the observed CMF among the starless cores in the Pipe Nebula. Our results indicate that in environment similar to the Pipe Nebula: (1) before the onset of their gravitational collapse, the mass distribution of the progenitor cores is similar to that of the young stars, (2) the observed CMF is a robust consequence of dynamical equilibrium between the coagulation and ablation of cores, and (3) a break in the slope of the CMF is due to the enhancement of collisional cross section and suppression of ablation for cores with masses larger than the cores' Bonnor-Ebert mass.

Huang Xu; Zhou Tingtao; Lin, D. N. C., E-mail: xuhuang@princeton.edu [Kavli Institute for Astronomy and Astrophysics and School of Physics, Peking University, Beijing (China)

2013-05-20T23:59:59.000Z

105

Effects of test environment and grain size on the tensile properties of L1 sub 2 -ordered (Co,Fe) sub 3 V alloys  

SciTech Connect (OSTI)

The influence of test environment, grain size, and heat treatment on the tensile properties and fracture behavior of L1{sub 2}-ordered (Co{sub 78}Fe{sub 22}){sub 3}V and (Co{sub 85}Fe{sub 15}){sub 3}V alloys was studied at room temperature. The tensile ductility depends strongly on test environments; the elongation decreases in the sequence of oxygen, vacuum, air, and distilled water. The loss in elongation is accompanied by a change in fracture mode from transgranular to intergranular. When tested in oxygen or vacuum, (Co{sub 78}Fe{sub 22}){sub 3}V specimens exhibited predominantly transgranular fracture, while (Co{sub 85}Fe{sub 15}){sub 3}V specimens exhibited essentially intergranular fracture. Grain refinement of (Co{sub 78}Fe{sub 22}){sub 3}V resulted in a ductility improvement in air, while such a beneficial effect of a grain refinement was not observed in (Co{sub 85}Fe{sub 15}){sub 3}V. These results suggest that: (1) (Co,Fe){sub 3}V alloys exhibit a moisture-induced hydrogen embrittlement and (2) grain boundaries are more intrinsically brittle in (Co{sub 85}Fe{sub 15}){sub 3}V than in (Co{sub 78}Fe{sub 22}){sub 3}V. The presence of a brittle hexagonal phase is suggested to be the reason for the observed grain-boundary brittleness in (Co{sub 85}Fe{sub 15}){sub 3}V. 29 refs., 6 figs., 2 tabs.

Nishimura, C.; Liu, C.T.

1991-01-01T23:59:59.000Z

106

Assessing the distribution, habitat, and population size of the threatened Dupont's lark Chersophilus  

E-Print Network [OSTI]

North African range, as well as on its preferred habitat, population density and size. Fieldwork), with important populations believed to be present in the steppe-like habitat of North Africa (Cramp, 1988Assessing the distribution, habitat, and population size of the threatened Dupont's lark

Oñate, Juan J.

107

GRAIN SORTING IN COMETARY DUST FROM THE OUTER SOLAR NEBULA  

SciTech Connect (OSTI)

Most young stars are surrounded by a disk of gas and dust. Close to the hot stars, amorphous dust grains from the parent molecular cloud are reprocessed into crystals that are then distributed throughout the accretion disk. In some disks, there is a reduction in crystalline grain size with heliocentric distance from the star. We investigated crystalline grain size distributions in chondritic porous (CP) interplanetary dust particles (IDPs) believed to be from small, icy bodies that accreted in outer regions of the solar nebula. The grains are Mg-rich silicates and Fe-rich sulfides, the two most abundant minerals in CP IDPs. We find that they are predominantly <0.25 {mu}m in radius with a mean grain size that varies from one CP IDP to another. We report a size-density relationship between the silicates and sulfides. A similar size-density relationship between much larger silicate and sulfide grains in meteorites from the asteroid belt is ascribed to aerodynamic sorting. Since the silicate and sulfide grains in CP IDPs are theoretically too small for aerodynamic sorting, their size-density relationship may be due to another process capable of sorting small grains.

Wozniakiewicz, P. J.; Bradley, J. P.; Ishii, H. A. [Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Brownlee, D. E. [Department of Astronomy, University of Washington, Seattle, WA (United States); Kearsley, A. T. [Department of Mineralogy, Natural History Museum, London SW7 5BD (United Kingdom); Burchell, M. J.; Price, M. C., E-mail: P.Wozniakiewicz@kent.ac.uk [School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH (United Kingdom)

2012-12-01T23:59:59.000Z

108

Condensation on Surface Energy Gradient Shifts Drop Size Distribution toward Small Drops  

E-Print Network [OSTI]

Condensation on Surface Energy Gradient Shifts Drop Size Distribution toward Small Drops Ashley M condensation from vapor onto a cooled surface, distributions of drops evolve by nucleation, growth is condensed onto a horizontally oriented surface that has been treated by silanization to deliver either

Daniel, Susan

109

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

SciTech Connect (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

110

TIME INTEGRATED MEASUREMENTS OF THE ACTIVITY-WEIGHTED SIZE DISTRIBUTION OF RADON PROGENY by  

E-Print Network [OSTI]

The dose to the lung is dependent on the size distribution as well as the concentration of radon progeny. The principal indicator of particle size is the diffusion coefficient. The diffusion coefficient of radon progeny is the most important parameter in determining whether the particle will deposit its alpha energy in the tracheobronchial region of the respiratory tract. Due to the importance of the size distribution of progeny when characterizing health effects, a detector was developed that exploits the difference in diffusion coefficients to provide integrated measurements of the activity-weighted size distribution. Several radon chamber tests were performed in which the diffusion coefficient and unattached fraction of radon progeny were varied by the use of trace gasses and aerosol particles. The technical feasibility of this new detector design was demonstrated in all cases.

William C. Tetley P. E; Daniel R. Westcott; Bruce A. Cununings

111

Spatial distribution and size evolution of particles in Asian outflow: Significance of primary and secondary aerosols during ACE-Asia  

E-Print Network [OSTI]

volatility suggested increasing neutralization of the aerosol during growth. Size distribution measurements; KEYWORDS: ACE-Asia, TRACE-P, aerosol size distribution, nucleation, primary and secondary aerosols, condensation and coagulation Citation: Mc Naughton, C. S., et al. (2004), Spatial distribution and size

112

Development of laboratory and process sensors to monitor particle size distribution of industrial slurries  

SciTech Connect (OSTI)

In this paper we present a novel measurement technique for monitoring particle size distributions of industrial colloidal slurries based on ultrasonic spectroscopy and mathematical deconvolution. An on-line sensor prototype has been developed and tested extensively in laboratory and production settings using mineral pigment slurries. Evaluation to date shows that the sensor is capable of providing particle size distributions, without any assumptions regarding their functional form, over diameters ranging from 0.1 to 100 micrometers in slurries with particle concentrations of 10 to 50 volume percents. The newly developed on-line sensor allows one to obtain particle size distributions of commonly encountered inorganic pigment slurries under industrial processing conditions without dilution.

Pendse, H.P.

1992-10-01T23:59:59.000Z

113

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

SciTech Connect (OSTI)

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

114

Investigation of the relationship between chemical composition and size distribution of airborne particles by partial least  

E-Print Network [OSTI]

combustion sources, secondary aerosol, and coal-fired power plants. The size distribution, particle identified: secondary nitrate 1 and 2, remote traffic, secondary sulfate, lead, diesel traffic, coal-fired power plant, steel mill, nucleation, local traffic, and coke plant. Citation: Zhou, L., P. K. Hopke, C

Stanier, Charlie

115

A particle size distribution was determined from the image analysis. With more expensive equipment,  

E-Print Network [OSTI]

contributes to fines generation during mining operations, the best practice is to replace drill bits Distribution Analysis Overview Kennametal, Incorporated is a major manufacturer of drill bits for mining ideally sized, half-inch pieces of coal. Because dull drill bits on mining machines significantly

Demirel, Melik C.

116

Probe measurements and numerical model predictions of evolving size distributions in premixed flames  

SciTech Connect (OSTI)

Particle size distributions (PSDs), measured with a dilution probe and a Differential Mobility Analyzer (DMA), and numerical predictions of these PSDs, based on a model that includes only coagulation or alternatively inception and coagulation, are compared to investigate particle growth processes and possible sampling artifacts in the post-flame region of a C/O = 0.65 premixed laminar ethylene-air flame. Inputs to the numerical model are the PSD measured early in the flame (the initial condition for the aerosol population) and the temperature profile measured along the flame's axial centerline. The measured PSDs are initially unimodal, with a modal mobility diameter of 2.2 nm, and become bimodal later in the post-flame region. The smaller mode is best predicted with a size-dependent coagulation model, which allows some fraction of the smallest particles to escape collisions without resulting in coalescence or coagulation through the size-dependent coagulation efficiency ({gamma}{sub SD}). Instead, when {gamma} = 1 and the coagulation rate is equal to the collision rate for all particles regardless of their size, the coagulation model significantly under predicts the number concentration of both modes and over predicts the size of the largest particles in the distribution compared to the measured size distributions at various heights above the burner. The coagulation ({gamma}{sub SD}) model alone is unable to reproduce well the larger particle mode (mode II). Combining persistent nucleation with size-dependent coagulation brings the predicted PSDs to within experimental error of the measurements, which seems to suggest that surface growth processes are relatively insignificant in these flames. Shifting measured PSDs a few mm closer to the burner surface, generally adopted to correct for probe perturbations, does not produce a better matching between the experimental and the numerical results. (author)

De Filippo, A.; Sgro, L.A.; Lanzuolo, G.; D'Alessio, A. [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, Piazzale Tecchio 80, 80125 Napoli (Italy)

2009-09-15T23:59:59.000Z

117

A Method to Increase Current Density in a Mono Element Internal Tin Processed Superconductor Utilizing Zr Oxide to Refine Grain Size  

SciTech Connect (OSTI)

The effect of Oxygen on (Nb1Zr)3Sn multifilament conductors manufactured by the Mono Element Internal Tin (MEIT) process was explored to improve the current density by refining the grain size. This followed work first done by General Electric on the Nb3Sn tape process. Techniques to fabricate the more difficult Nb1Zr composites are described and allowed fabrication of long lengths of .254 mm diameter wire from an 88.9 mm diameter billet. Oxygen was incorporated through the use of SnO2 mixed with tin powder and incorporated into the core. These were compared to samples with Ti+Sn and Cu+Sn cores. Heat treatments covered the range of 700 C to 1000 C. Current density vs. H, grain size, and reaction percentages are provided for the materials tested. The Oxygen gave superior results in the temperature range of 815-1000 C. It also stabilized the filament geometry of the array in comparison to the other additions at the higher temperatures. At 815 C a peak in layer Jc yielded values of 2537 A/mm2 at 12 T and 1353 A/mm2 at 15T, 8-22% and 30-73% greater respectively than 700 C values. Results with Oxygen at high temperature show the possibility of high speed continuous reaction of the composite versus the current batch or react in place methods. In general the Ti additions gave superior results at the lower reaction temperature. Future work is suggested to determine if the 815 C reaction temperature can lead to higher current density in high tin (Nb1Zr+Ox)3Sn conductors. A second technique incorporated oxygen directly into the Nb1Zr rods through heat treatment with Nb2O5 at 1100 C for 100 hours in vacuum prior to extrusion. The majority of the filaments reduced properly in the composite but some local variations in hardness led to breakage at smaller diameters.

Bruce A. Zeitlin, Eric Gregory

2008-04-07T23:59:59.000Z

118

SIZE DISTRIBUTION AND RATE OF PRODUCTION OF AIRBORNE PARTICULATE MATTER GENERATED DURING METAL CUTTING  

SciTech Connect (OSTI)

During deactivation and decommissioning activities, thermal cutting tools, such as plasma torch, laser, and gasoline torch, are used to cut metals. These activities generate fumes, smoke and particulates. These airborne species of matter, called aerosols, may be inhaled if suitable respiratory protection is not used. Inhalation of the airborne metallic aerosols has been reported to cause ill health effects, such as acute respiratory syndrome and chromosome damage in lymphocytes. In the nuclear industry, metals may be contaminated with radioactive materials. Cutting these metals, as in size reduction of gloveboxes and tanks, produces high concentrations of airborne transuranic particles. Particles of the respirable size range (size < 10 {micro}m) deposit in various compartments of the respiratory tract, the fraction and the site in the respiratory tract depending on the size of the particles. The dose delivered to the respiratory tract depends on the size distribution of the airborne particulates (aerosols) and their concentration and radioactivity/toxicity. The concentration of airborne particulate matter in an environment is dependent upon the rate of their production and the ventilation rate. Thus, measuring aerosol size distribution and generation rate is important for (1) the assessment of inhalation exposures of workers, (2) the selection of respiratory protection equipment, and (3) the design of appropriate filtration systems. Size distribution of the aerosols generated during cutting of different metals by plasma torch was measured. Cutting rates of different metals, rate of generation of respirable mass, as well as the fraction of the released kerf that become respirable were determined. This report presents results of these studies. Measurements of the particles generated during cutting of metal plates with a plasma arc torch revealed the presence of particles with mass median aerodynamic diameters of particles close to 0.2 {micro}m, arising from condensation of vaporized material and subsequent rapid formation of aggregates. Particles of larger size, resulting from ejection of melted material or fragments from the cutting zone, were also observed. This study presents data regarding the metal cutting rate, particle size distribution, and their generation rate, while using different cutting tools and metals. The study shows that respirable particles constitute only a small fraction of the released kerf.

M.A. Ebadian, Ph.D.; S.K. Dua, Ph.D., C.H.P.; Hillol Guha, Ph.D.

2001-01-01T23:59:59.000Z

119

E-Print Network 3.0 - alloys grain refinement Sample Search Results  

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

in iron substitutional alloys (Grain size effects on iron... ;14 Objective Grain Size Varistors Hall- Petch Creep Grain refinement A crucial engineering consequence... of the...

120

E-Print Network 3.0 - alloy grain refined Sample Search Results  

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

in iron substitutional alloys (Grain size effects on iron... ;14 Objective Grain Size Varistors Hall- Petch Creep Grain refinement A crucial engineering consequence... of the...

Note: This page contains sample records for the topic "grain 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

OXYGEN DEPLETION IN THE INTERSTELLAR MEDIUM: IMPLICATIONS FOR GRAIN MODELS AND THE DISTRIBUTION OF ELEMENTAL OXYGEN  

SciTech Connect (OSTI)

This paper assesses the implications of a recent discovery that atomic oxygen is being depleted from diffuse interstellar gas at a rate that cannot be accounted for by its presence in silicate and metallic oxide particles. To place this discovery in context, the uptake of elemental O into dust is considered over a wide range of environments, from the tenuous intercloud gas and diffuse clouds sampled by the depletion observations to dense clouds where ice mantles and gaseous CO become important reservoirs of O. The distribution of O in these contrasting regions is quantified in terms of a common parameter, the mean number density of hydrogen (n{sub H}). At the interface between diffuse and dense phases (just before the onset of ice-mantle growth) as much as {approx}160 ppm of the O abundance is unaccounted for. If this reservoir of depleted oxygen persists to higher densities it has implications for the oxygen budget in molecular clouds, where a shortfall of the same order is observed. Of various potential carriers, the most plausible appears to be a form of O-bearing carbonaceous matter similar to the organics found in cometary particles returned by the Stardust mission. The 'organic refractory' model for interstellar dust is re-examined in the light of these findings, and it is concluded that further observations and laboratory work are needed to determine whether this class of material is present in quantities sufficient to account for a significant fraction of the unidentified depleted oxygen.

Whittet, D. C. B. [New York Center for Astrobiology, and Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States)

2010-02-20T23:59:59.000Z

122

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

2014-08-14T23:59:59.000Z

123

The inertial and electrical effects on aerosol sampling, charging, and size distribution  

SciTech Connect (OSTI)

An experimental study was conducted to investigate the effect of particle inertia on deposition behavior near the filter cassette sampler. Field sampling cassettes were tested in a subsonic wind tunnel for 0.2, 0.5 and 0.68 m/s wind speeds to simulate indoor air environment. Fluorescein aerosols of 2 and 5 {mu}m were generated from Berglund-Liu vibrating orifice generator as test material. Sampling tests were conducted in a subsonic wind tunnel with variables of particle size, wind speed, suction velocity and orientation of sampler examined to evaluate the combined effects. Sampling efficiencies were also examined. Electrostatic force is usually used as an effective method for removing, classifying and separating aerosols according to the electrical mobilities of the particulates. On the other hand, the aerosol charging theories possess differences in the ultrafine size range and need experimental verification. The present TSI's electrostatic aerosol analyzer has particle loss problem and cannot be used as a reliable tool in achieving efficient charging. A new unipolar charger with associated electronic circuits was designed, constructed and tested. The performance of the charger is tested in terms of particle loss, uncharged particles, and the collection efficiency of the precipitator. The results were compared with other investigator's data. The log-Beta distribution function is considered to be more versatile in representing size distribution. This study discussed the method in determining the size parameters under different conditions. Also the mutability of size distribution was evaluated when particles undergo coagulation or classification processes. Comparison of evolution between log-Beta and lognormal distributions were made.

Wang, Chuenchung.

1991-01-01T23:59:59.000Z

124

Particle Size Distribution Data From Existing Boreholes at the Immobilized Low-Activity Waste Site  

SciTech Connect (OSTI)

This report provides particle size distribution data for samples near the Immobilized Low-Activity Waste (ILAW) Site that were archived in the Hanford Geotechnical Sample Library. Seventy-nine sediment samples were analyzed from four boreholes. Samples were collected from every ten feet in the boreholes. Eightly percent of the samples were classified as slightly gravelly sand. Fifteen percent were classified as gravelly sand, gravelly silty sand, or sandy gravels. These data indicate that the particle size of the sediment is consistent across the ILAW site and is dominated by sand in the upper part of the Hanford formation with more gravel rich units in the lower part.

Valenta, Michelle M.; Martin, Maria B.; Moreno, Jorge R.; Ferri, Rosalie M.; Horton, Duane G.; Reidel, Stephen P.

2000-09-25T23:59:59.000Z

125

Crystallographic Characteristics of Grain Boundaries in Dense Yttria-Stabilized Zirconia  

SciTech Connect (OSTI)

Grain-boundary plane, misorientation angle, grain size, and grain-boundary energy distributions were quantified using electron backscatter diffraction data for dense polycrystalline yttria-stabilized zirconia, to understand interfacial crystallography in solid oxide fuel cells. Tape-cast samples were sintered at 14501C for 4 h and annealed for at least 100 h between 8001C and 16501C. Distributions obtained from both three-dimensional (3D) reconstructions and stereological analyses of 2D sections demonstrated that the (100) boundary planes {(111)} have relative areas larger {smaller} than expected in a random distribution, and that the boundary plane distribution is inversely correlated to the boundary energy distribution.

Lam Helmick; Shen J. Dillon; Kirk Gerdes; Randall Gemmen; Gregory S. Rohrer; Sridhar Seetharaman; Paul A. Salvador

2010-04-01T23:59:59.000Z

126

Size distribution of metals in particulate matter formed during combustion of residual fuel oil  

SciTech Connect (OSTI)

Between July 1992 and January 1993 three full-scale test programs were performed by Carnot for the Electric Power Research Institute and the Fuel Oil Users` Support (FOUS) Group, as part of a program for development and testing of various stack emissions models. One of the components of the program was determination of the concentrations of individual elements as a function of the size of particles suspended in flue gas. The size distributions of species are important because several aspects of system performance depend upon particulate matter size and composition: (1) the rate of ash deposition in the convection section, and activity of deposits for high temperature corrosion and SO{sub 3} formation, (2) the efficiency of precipitators for collection of individual elements, and (3) scattering of visible light and contribution of particles to stack plume opacity. Size distributions of major ash constituents were measured at the entrance and exit of the dust collectors during each of the field tests. To the authors` knowledge, these are the first reports of such measurements in residual oil-fired utility boilers. The focus, in the present paper, is on the composition of the particles entering the dust collectors.

Walsh, P. [Pennsylvania State Univ., University Park, PA (United States); Rovesti, W.C. [Electric Power Research Institute, Washington, DC (United States); Freeman, R.F. [Niagara Mohawk Power Corp., Oswego, NY (United States); Olen, K.R.; Washington, K.T.; Patrick, S.T.; Campbell, G.L.; Harper, D.S. [Florida Power & Light Co., West Palm Beach, FL (United States); Teetz, R.D.; Bennett, T.E. [Long Island Lighting Co., Glenwood Landing, NY (United States)] [and others

1994-08-01T23:59:59.000Z

127

Grain size effect on the giant dielectric constant of CaCu{sub 3}Ti{sub 4}O{sub 12} nanoceramics prepared by mechanosynthesis and spark plasma sintering  

SciTech Connect (OSTI)

In the present work, CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) nanoceramics with different grain sizes were prepared by spark plasma sintering (SPS) at different temperatures (SPS-800, SPS-900, SPS-975, and SPS-1050) of the mechanosynthesized nano-powder. Structural and microstructural properties were studied by XRD and field-emission scanning electron microscope measurements. The grain size of CCTO nanoceramics increases from 80?nm to ?200?nm for the ceramics sintered at 800?C and 975?C, respectively. Further increase of SPS temperature to 1050?C leads to micro-sized ceramics of 23??m. The electrical and dielectric properties of the investigated ceramics were studied by impedance spectroscopy. Giant dielectric constant was observed in CCTO nanoceramics. The dielectric constant increases with increasing the grain size of the nanoceramics with values of 8.3??10{sup 3}, 2.4??10{sup 4}, and 3.2??10{sup 4} for SPS-800, SPS-900, and SPS-975, respectively. For the micro-sized SPS-1050 ceramics, the dielectric constant dropped to 2.14??10{sup 4}. The dielectric behavior is interpreted within the internal barrier layer capacitance picture due to the electrical inhomogeneity of the ceramics. Besides the resistive grain boundaries that are usually observed in CCTO ceramics, domain boundaries appear as a second source of internal layers in the current nanoceramics.

Ahmad, Mohamad M., E-mail: mmohamad@kfu.edu.sa [Department of Physics, College of Science, King Faisal University, Al-Ahsaa 31982 (Saudi Arabia); Department of Physics, Faculty of Science, Assiut University in the New Valley, El-Kharga 72511 (Egypt); Yamada, Koji [Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, Narashino, Chiba 275-8575 (Japan)

2014-04-21T23:59:59.000Z

128

Soil water and particle size distribution influence laboratory-generated PM10 Nicholaus M. Madden a,*, Randal J. Southard a  

E-Print Network [OSTI]

on gravimetric soil water content (GWC) and soil texture. A mechanical laboratory dust generator was used to testSoil water and particle size distribution influence laboratory-generated PM10 Nicholaus M. Madden a Soil particle size distribution Soil water content a b s t r a c t Management of soils to reduce

Ahmad, Sajjad

129

The effect of gravel size fraction on the distribution coefficients of selected radionuclides  

SciTech Connect (OSTI)

This manuscript addresses the consequences of the common practice of assuming that the gravel fraction of sediments does not participate in sorption reactions and thus sorption quantified by the distribution coefficient (Kd) construct can be estimated from laboratory tests on sediments less than 2 mm size fraction. However, this common assumption can lead to inaccurate estimates of the mobility and sorption affinity of many radionuclides (e.g., Tc, U, and Np) on gravel dominated sediments at the Hanford Site and other locations. Laboratory batch sorption experiments showed that the distribution coefficients measured using only sediment less than 2 mm size fraction and correcting for inert gravel fraction were not in agreement with those obtained from the bulk sediments including gravel (larger than 2 mm size fraction), depending on the radionuclide. The least reactive radionuclide, Tc had Kd values for bulk sediment with negligible deviations from the inert gravel corrected Kd values measured on less than 2 mm size fraction. However, differences between measured Kd values using sediment less than 2 mm size fraction and the Kd values on the bulk sediment were significant for intermediately and strongly reactive radionuclides such as U and Np, especially on the sediment with gravel fractions that contained highly reactive sites. Highly reactive sites in the gravel fraction were attributed to the presence of Fe oxide coatings and/or reactive fracture faces on the gravel surfaces. Gravel correction factors that use the sum of the Kd,<2 mm and Kd,>2 mm values to estimate the Kd for the bulk sediment were found to best describe Kd values for radionuclides on the bulk sediment. Gravel correction factors should not be neglected to predict precisely the sorption capacity of the bulk sediments that contain more than 30% gravel. In addition, more detailed characterization of gravel surfaces should be conducted to identify whether higher reactive sorbents are present in the gravels.

Um, Wooyong; Serne, R. Jeffrey; Last, George V.; Clayton, Ray E.; Glossbrenner, Ellwood T.

2009-06-26T23:59:59.000Z

130

Optimization of Comminution Circuit Throughput and Product Size Distribution by Simulation and Control  

SciTech Connect (OSTI)

The goal of this project is to improve energy efficiency of industrial crushing and grinding operations (comminution). Mathematical models of the comminution process are being used to study methods for optimizing the product size distribution, so that the amount of excessively fine material produced can be minimized. The goal is to save energy by reducing the amount of material that is ground below the target size, while simultaneously reducing the quantity of materials wasted as ''slimes'' that are too fine to be useful. This is being accomplished by mathematical modeling of the grinding circuits to determine how to correct this problem. The approaches taken included (1) Modeling of the circuit to determine process bottlenecks that restrict flow rates in one area while forcing other parts of the circuit to overgrind the material; (2) Modeling of hydrocyclones to determine the mechanisms responsible for retaining fine, high-density particles in the circuit until they are overground, and improving existing models to accurately account for this behavior; and (3) Evaluation of advanced technologies to improve comminution efficiency and produce sharper product size distributions with less overgrinding.

S. K. Kawatra; T. C. Eisele; T. Weldum; D. Larsen; R. Mariani; J. Pletka

2005-03-31T23:59:59.000Z

131

OPTIMIZATION OF COMMINUTION CIRCUIT THROUGHPUT AND PRODUCT SIZE DISTRIBUTION BY SIMULATION AND CONTROL  

SciTech Connect (OSTI)

The goal of this project is to improve energy efficiency of industrial crushing and grinding operations (comminution). Mathematical models of the comminution process are being used to study methods for optimizing the product size distribution, so that the amount of excessively fine material produced can be minimized. The goal is to save energy by reducing the amount of material that is ground below the target size, while simultaneously reducing the quantity of materials wasted as ''slimes'' that are too fine to be useful. This is being accomplished by mathematical modeling of the grinding circuits to determine how to correct this problem. The approaches taken included (1) Modeling of the circuit to determine process bottlenecks that restrict flowrates in one area while forcing other parts of the circuit to overgrind the material; (2) Modeling of hydrocyclones to determine the mechanisms responsible for retaining fine, high-density particles in the circuit until they are overground, and improving existing models to accurately account for this behavior; and (3) Evaluation of advanced technologies to improve comminution efficiency and produce sharper product size distributions with less overgrinding.

S.K. Kawatra; T.C. Eisele; T. Weldum; D. Larsen; R. Mariani; J. Pletka

2005-01-01T23:59:59.000Z

132

The effect of dust size distribution on quantum dust acoustic wave  

SciTech Connect (OSTI)

Based on the quantum hydrodynamics theory, a proposed model for quantum dust acoustic waves (QDAWs) is presented including the dust size distribution (DSD) effect. A quantum version of Zakharov-Kuznetsov equation is derived adequate for describing QDAWs. Two different DSD functions are applied. The relevance of the wave velocity, amplitude, and width to the DSD is investigated numerically. The quantum effect changes only the soliton width. A brief conclusion is presented to the current findings and their relevance to astrophysics data is also discussed.

El-Labany, S. K.; El-Taibany, W. F.; Behery, E. E. [Department of Physics, Faculty of Science, Mansoura University, Damietta Branch, Damietta El-Gedida, P.O. 34517 (Egypt); El-Siragy, N. M. [Department of Physics, Faculty of Science, Tanta University, Tanta, P.O. 31527 (Egypt)

2009-09-15T23:59:59.000Z

133

Size distributions of fly ash using Coulter Multisizer: Use of multiple orifices and fitting to truncated log-normal distributions. [Coulter Multisizer  

SciTech Connect (OSTI)

Fly ash particles, which are predominantly spherical and glassy, are produced by melting of the mineral inclusions in the coal during combustion. Particle diameters can range from sub-micrometer (micron or {mu}m) to greater than 100 {mu}m. The size distribution of fly ash is needed to determine its role in the radiation transfer process in pulverized coal combustors. The Coulter Multisizer is an useful instrument for sizing powders with a broad size distribution. A single Multisizer orifice can size particles only within a specific size range limited at the lower end to a few percent of orifice diameter by sensitivity and at the upper end by increasing non-linearity of the signal-volume relation. A scheme for combining data obtained using orifices of different diameters is described. The manufacturers state that the smallest particle which can be sized accurately is nominally 2% of the diameter of the orifice. However, it was found that the data for particles less than 4% of the orifice diameter were not reliable. In order to use the smaller orifices, the larger particles have to be removed from the sample. A wet-sieving apparatus, designed for accurate separation of the particles by size, is described. A log-normal distribution function, truncated outside the measurement limits, fits the size distribution data well. Size parameters for fly ashes of six representative US coals are presented.

Ghosal, S.; Ebert, J.L.; Self, S.A.

1991-11-01T23:59:59.000Z

134

Paramagnetic alignment of fractal grains  

E-Print Network [OSTI]

Paramagnetic alignment of fractal suprathermally rotating grains is discussed. It is shown that if the concentration of H$_{2}$formation sites is low and resurfacing is active, fractal structure of grains enhances their alignment. Studying the influence of grain surface physics and chemistry on the alignment we found that there exist two critical values of grain sizes, and the alignment of smaller grains is expected to decrease as compared to the predictions of the Purcell's theory (1979). One of the critical sizes is due to intensified poisoning of active sites, while the other is a result of a finite value of the imaginary part of magnetic susceptibility in the limit of high angular velocities. On the contrary, if active sites completely cover grain surface, suprathermal rotation, and therefore efficient alignment, is possible only for a limited range of grain sizes.

A. Lazarian

1994-08-23T23:59:59.000Z

135

The effect of sand grain size distribution on the minimum oil saturation necessary to support in-situ combustion  

E-Print Network [OSTI]

. Daniel, B. S. , Texas A8cM University; Directed by: Dr, Joseph S. Osoba The use of in-situ combustion as a means of producing heavy, viscous crude oils is not new. However, the success of this method of producing crude oil has been limited.... : "In-Situ Combustion--- Newest Method of Increasing Oil Recovery, " The Oil and Gas Journal (August 10 ~ 1953) 52. Grant, B. F. , and Szasz, S. E. : "Development of an Underground Heat Wave for Oil Recovery, " Trans. AIME (1954) 201, 108. Nelson...

Daniel, William Marvin

1973-01-01T23:59:59.000Z

136

Optimization of Comminution Circuit Throughput and Product Size Distribution by Simulation and Control  

SciTech Connect (OSTI)

The goal of this project was to improve energy efficiency of industrial crushing and grinding operations (comminution). Mathematical models of the comminution process were used to study methods for optimizing the product size distribution, so that the amount of excessively fine material produced could be minimized. The goal was to save energy by reducing the amount of material that was ground below the target size, while simultaneously reducing the quantity of materials wasted as ''slimes'' that were too fine to be useful. Extensive plant sampling and mathematical modeling of the grinding circuits was carried out to determine how to correct this problem. The approaches taken included (1) Modeling of the circuit to determine process bottlenecks that restrict flowrates in one area while forcing other parts of the circuit to overgrind the material; (2) Modeling of hydrocyclones to determine the mechanisms responsible for retaining fine, high-density particles in the circuit until they are overground, and improving existing models to accurately account for this behavior; and (3) Evaluation of the potential of advanced technologies to improve comminution efficiency and produce sharper product size distributions with less overgrinding. The mathematical models were used to simulate novel circuits for minimizing overgrinding and increasing throughput, and it is estimated that a single plant grinding 15 million tons of ore per year saves up to 82.5 million kWhr/year, or 8.6 x 10{sup 11} BTU/year. Implementation of this technology in the midwestern iron ore industry, which grinds an estimated 150 million tons of ore annually to produce over 50 million tons of iron ore concentrate, would save an estimated 1 x 10{sup 13} BTU/year.

S.K. Kawatra; T.C. Eisele; T. Weldum; D. Larsen; R. Mariani; J. Pletka

2005-07-01T23:59:59.000Z

137

In situ diagnostic of the size distribution of nanoparticles generated by ultrashort pulsed laser ablation in vacuum  

SciTech Connect (OSTI)

We aim to characterize the size distribution of nanoparticles located in the ablation plume produced by femtosecond laser interaction. The proposed method relies on the use of white-light extinction spectroscopy setup assisted by ultrafast intensified temporal gating. This method allows measurement of optical absorbance of a nickel nanoparticles cloud. Simulation of the extinction section of nickel nanoparticles size distributions has been developed in order to compare the measured optical absorbance to the optical extinction by theoretical and experimental nanoparticles size distributions (measured by scanning electron microscopy). A good agreement has been found between the in situ measured optical absorbance and the optical extinction cross section calculated from ex situ nanoparticles size distribution measurements.

Bourquard, Florent; Loir, Anne-Sophie; Donnet, Christophe; Garrelie, Florence, E-mail: florence.garrelie@univ-st-etienne.fr [Universit de Lyon, CNRS UMR 5516, Laboratoire Hubert Curien, Universit Jean Monnet, Saint-tienne (France)] [Universit de Lyon, CNRS UMR 5516, Laboratoire Hubert Curien, Universit Jean Monnet, Saint-tienne (France)

2014-03-10T23:59:59.000Z

138

Polarized light propagation in highly scattering turbid media with a distribution of the particle size: a Monte Carlo study  

E-Print Network [OSTI]

The light propagation in highly scattering turbid media composed of the particles with different size distribution is studied using a Monte Carlo simulation model implemented in Standard C. Monte Carlo method has been widely utilized to study...

Koh, Wonshill

2013-02-22T23:59:59.000Z

139

Determination of aerosol size distributions at uranium mill tailings remedial action project sites  

SciTech Connect (OSTI)

The U.S. Department of Energy (DOE) has an ongoing program, the Uranium Mill Tailings Remedial Action (UMTRA) Project, to stabilize piles of uranium mill tailings in order to reduce the potential radiological hazards to the public. Protection of workers and the general public against airborne radioactivity during remedial action is a top priority at the UMTRA Project. The primary occupational radionuclides of concern are {sup 230}Th, {sup 226}Ra, {sup 210}Pb, {sup 210}Po, and the short-lived decay products of {sup 222}Rn with {sup 230}Th causing the majority of the committed effective dose equivalent (CEDE) from inhaling uranium mill tailings. Prior to this study, a default particle size of 1.0 {mu}m activity median aerodynamic diameter (AMAD) was assumed for airborne radioactive tailings dust. Because of recent changes in DOE requirements, all DOE operations are now required to use the CEDE methodology, instead of the annual effective dose equivalent (AEDE) methodology, to evaluate internal radiation exposures. Under the transition from AEDE to CEDE, with a 1.0 {mu}m AMAD particle size, lower bioassay action levels would be required for the UMTRA Project. This translates into an expanded internal dosimetry program where significantly more bioassay monitoring would be required at the UMTRA Project sites. However, for situations where the particle size distribution is known to differ significantly from 1.0 {mu}m AMAD, the DOE allows for corrections to be made to both the estimated dose to workers and the derived air concentration (DAC) values. For particle sizes larger than 1.0 {mu}m AMAD, the calculated CEDE from inhaling tailings would be relatively lower.

Newton, G.J.; Reif, R.H. [CWM Federal Environmental Services, Inc., Albuquerque, NM (United States); Hoover, M.D.

1994-11-01T23:59:59.000Z

140

The influence of increasing population size and vegetation productivity on elephant distribution in the Kruger National Park  

E-Print Network [OSTI]

-cell occupancy increased with population size, while grid-cell-specific density became less variable. In additionThe influence of increasing population size and vegetation productivity on elephant distribution Research Unit, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa

Pretoria, University of

Note: This page contains sample records for the topic "grain 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

Science at the interface : grain boundaries in nanocrystalline metals.  

SciTech Connect (OSTI)

Interfaces are a critical determinant of the full range of materials properties, especially at the nanoscale. Computational and experimental methods developed a comprehensive understanding of nanograin evolution based on a fundamental understanding of internal interfaces in nanocrystalline nickel. It has recently been shown that nanocrystals with a bi-modal grain-size distribution possess a unique combination of high-strength, ductility and wear-resistance. We performed a combined experimental and theoretical investigation of the structure and motion of internal interfaces in nanograined metal and the resulting grain evolution. The properties of grain boundaries are computed for an unprecedented range of boundaries. The presence of roughening transitions in grain boundaries is explored and related to dramatic changes in boundary mobility. Experimental observations show that abnormal grain growth in nanograined materials is unlike conventional scale material in both the level of defects and the formation of unfavored phases. Molecular dynamics simulations address the origins of some of these phenomena.

Rodriguez, Mark Andrew; Follstaedt, David Martin; Knapp, James Arthur; Brewer, Luke N.; Holm, Elizabeth Ann; Foiles, Stephen Martin; Hattar, Khalid M.; Clark, Blythe B.; Olmsted, David L.; Medlin, Douglas L.

2009-09-01T23:59:59.000Z

142

Energy conservation potential of Portland cement particle size distribution control, Phase 2  

SciTech Connect (OSTI)

The main objectives of Phase 2 are to determine the feasibility of using cements with controlled particle size distributions (CPSD cements) in practical concrete applications, and to refine our estimates of the potential energy savings that may ensue from such use. The work in Phase 2 is divided into two main tasks, some parts of which will be carried out simultaneously: Task 1 will continue cement paste studies to optimize cement performance similar to those of Phase 1, but with particular emphasis on gypsum requirements, blended cements, and water-reducing admixtures. This task will also include preparation of sufficient CPSD cements for use in all Phase 2 work. Task 2 will be a comprehensive examination of the properties of concretes made with CPSD cements. This will include optimization of concrete mix designs to obtain the best possible performance for practical applications of both portland and blended cements. The effects of chemical admixtures and curing temperature variations will also be determined.

Helmuth, R.A; Whiting, D.A.

1983-01-01T23:59:59.000Z

143

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

SciTech Connect (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

144

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

SciTech Connect (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

145

DECODING THE MESSAGE FROM METEORITIC STARDUST SILICON CARBIDE GRAINS  

SciTech Connect (OSTI)

Micron-sized stardust grains that originated in ancient stars are recovered from meteorites and analyzed using high-resolution mass spectrometry. The most widely studied type of stardust is silicon carbide (SiC). Thousands of these grains have been analyzed with high precision for their Si isotopic composition. Here we show that the distribution of the Si isotopic composition of the vast majority of stardust SiC grains carries the imprints of a spread in the age-metallicity distribution of their parent stars and of a power-law increase of the relative formation efficiency of SiC dust with the metallicity. This result offers a solution for the long-standing problem of silicon in stardust SiC grains, confirms the necessity of coupling chemistry and dynamics in simulations of the chemical evolution of our Galaxy, and constrains the modeling of dust condensation in stellar winds as a function of the metallicity.

Lewis, Karen M.; Lugaro, Maria; Gibson, Brad K.; Pilkington, Kate, E-mail: maria.lugaro@monash.edu, E-mail: karen.michelle.lewis@gmail.com, E-mail: bkgibson@uclan.ac.uk, E-mail: kpilkington@uclan.ac.uk [Monash Centre for Astrophysics (MoCA), Monash University, Clayton VIC 3800 (Australia)

2013-05-01T23:59:59.000Z

146

Decoding the message from meteoritic stardust silicon carbide grains  

E-Print Network [OSTI]

Micron-sized stardust grains that originated in ancient stars are recovered from meteorites and analysed using high-resolution mass spectrometry. The most widely studied type of stardust is silicon carbide (SiC). Thousands of these grains have been analysed with high precision for their Si isotopic composition. Here we show that the distribution of the Si isotopic composition of the vast majority of stardust SiC grains carry the imprints of a spread in the age-metallicity distribution of their parent stars and of a power-law increase of the relative formation efficiency of SiC dust with the metallicity. This result offers a solution for the long-standing problem of silicon in stardust SiC grains, confirms the necessity of coupling chemistry and dynamics in simulations of the chemical evolution of our Galaxy, and constrains the modelling of dust condensation in stellar winds as function of the metallicity.

Lewis, Karen M; Gibson, Brad K; Pilkington, Kate

2013-01-01T23:59:59.000Z

147

Collection strategy, inner morphology, and size distribution of dust particles in ASDEX Upgrade  

SciTech Connect (OSTI)

The dust collection and analysis strategy in ASDEX Upgrade (AUG) is described. During five consecutive operation campaigns (20072011), Si collectors were installed, which were supported by filtered vacuum sampling and collection with adhesive tapes in 2009. The outer and inner morphology (e.g. shape) and elemental composition of the collected particles were analysed by scanning electron microscopy. The majority of the ~50?000 analysed particles on the Si collectors of campaign 2009 contain tungstenthe plasma-facing material in AUGand show basically two different types of outer appearance: spheroids and irregularly shaped particles. By far most of the W-dominated spheroids consist of a solid W core, i.e. solidified W droplets. A part of these particles is coated with a low-Z material; a process that seems to happen presumably in the far scrape-off layer plasma. In addition, some conglomerates of B, C and W appear as spherical particles after their contact with plasma. By far most of the particles classified as B-, C- and W-dominated irregularly shaped particles consist of the same conglomerate with varying fraction of embedded W in the BC matrix and some porosity, which can exceed 50%. The fragile structures of many conglomerates confirm the absence of intensive plasma contact. Both the ablation and mobilization of conglomerate material and the production of W droplets are proposed to be triggered by arcing. The size distribution of each dust particle class is best described by a log-normal distribution allowing an extrapolation of the dust volume and surface area. The maximum in this distribution is observed above the resolution limit of 0.28 m only for the W-dominated spheroids, at around 1 m. The amount of W-containing dust is extrapolated to be less than 300 mg on the horizontal areas of AUG.

M. Balden; N. Endstrasser; P. W. Humrickhouse; V. Rohde; M. Rasinski; U. von Toussaint; S. Elgeti; R. Neu

2014-04-01T23:59:59.000Z

148

Combustion of sludge waste in FBC. Distribution of metals and particle sizes  

SciTech Connect (OSTI)

Due to the increases in the amounts of sludge generated and increasingly stringent regulations regarding its disposal, alternative methods to landfilling are becoming more important. Fluidized bed combustion is one such alternative, providing permanent disposal of the sludge. In this research, metal-solid particle characteristics during combustion of a sludge waste were studied. The sludge was a result of de-inking process. Experiments were carried out using a pilot-scale circulating fluidized bed combustion facility (CFB). The fluidized bed was operated in the bubbling mode. The sludge was separately burned with silica sand particles, ultrasorb particles, and alumina particles as bed materials. Major flue gas components (CO{sub 2}, CO, O{sub 2}, NO, NO{sub 2}) were measured continuously. Gas temperature profiles were determined using a water-cooled suction pyrometer. Solid particle samples were collected at multiple locations using a dilution tunnel sampling system. The solid samples were analyzed to determine ash structure, size and composition distributions. Metal analyses were performed using a computer-controlled Electron Probe Microanalyzer (EPMA) equipped with four Wavelength-Dispersive Spectrometers. Analyses of individual fly ash particles indicated that heavy metal elements (Pb, Cd, Cr, Cu, Ni) were generally located in regions near the particle`s core. Lighter metals (Si, Al, Ca, Na, K) were present across the entire cross-section of a particle, with the highest concentrations at the particle surface. These distributions were found to be similar regardless of the type of bed material. This suggests that the light metal layers are formed because of the internal rearrangements of a chemical nature as opposed to physical deposition of light metal fragments on particle surfaces.

Kozinski, J.A. [McGill Univ., Montreal, Quebec (Canada); Rink, K.K.; Lighty, J.S. [Univ. of Utah, Salt Lake City, UT (United States)

1995-12-31T23:59:59.000Z

149

Characterization of Vertical Velocity and Drop Size Distribution Parameters in Widespread Precipitation at ARM Facilities  

SciTech Connect (OSTI)

Extended, high-resolution measurements of vertical air motion and median volume drop diameter D0 in widespread precipitation from three diverse Atmospheric Radiation Measurement Program (ARM) locations [Lamont, Oklahoma, Southern Great Plains site (SGP); Niamey, Niger; and Black Forest, Germany] are presented. The analysis indicates a weak (0-10 cm{sup -1}) downward air motion beneath the melting layer for all three regions, a magnitude that is to within the typical uncertainty of the retrieval methods. On average, the hourly estimated standard deviation of the vertical air motion is 0.25 m s{sup -1} with no pronounced vertical structure. Profiles of D0 vary according to region and rainfall rate. The standard deviation of 1-min-averaged D0 profiles for isolated rainfall rate intervals is 0.3-0.4 mm. Additional insights into the form of the raindrop size distribution are provided using available dual-frequency Doppler velocity observations at SGP. The analysis suggests that gamma functions better explain paired velocity observations and radar retrievals for the Oklahoma dataset. This study will be useful in assessing uncertainties introduced in the measurement of precipitation parameters from ground-based and spaceborne remote sensors that are due to small-scale variability.

Giangrande S. E.; Luke, E. P.; Kollias, P.

2012-02-01T23:59:59.000Z

150

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

SciTech Connect (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

151

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

SciTech Connect (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

152

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

SciTech Connect (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

153

Effects of Sampling Conditions on the Size Distribution of Fine Particulate Matter Emitted from a Pilot-Scale  

E-Print Network [OSTI]

Effects of Sampling Conditions on the Size Distribution of Fine Particulate Matter Emitted from complex because the dilution ratio influences both the coagulation rate and gas-to- particle conversion because of their ability to scatter and absorb light and also because they act as cloud condensation

Stanier, Charlie

154

Joint Estimation of NDE Inspection Capability and Flaw-size Distribution for in-service Aircraft Inspections  

E-Print Network [OSTI]

1 Joint Estimation of NDE Inspection Capability and Flaw- size Distribution for in-service Aircraft, Dayton, OH 45469 Abstract: Nondestructive evaluation (NDE) is widely used in the aerospace industry of unknown existing cracks is more difficult. If NDE signal strength is recorded at all inspections

155

Size distribution of fine Particles in Stack emissions of a 600-MWe coal-fired Power Plant  

E-Print Network [OSTI]

Size distribution of fine Particles in Stack emissions of a 600-MWe coal-fired Power Plant I coal-fired power plant. Aknowledgements: French environment agency ADEME (Contract number 04-74-C0018 that was carried out in March 2006 at a 600-MWe coal-fired power plant. 51 ineris-00973267,version1-4Apr2014 Author

Paris-Sud XI, Université de

156

Three-dimensional Studies of Aerosol Ions and Their Size Distribution in East1 Asia During Spring 20012  

E-Print Network [OSTI]

2 condensation and gas phase ammonia distribution determine the nitrate size and32 gas observations. The regional27 chemical transport model, STEM-2K3, which includes the on-line gas-aerosol thermodynamic28 module SCAPE II, and explicitly considers chemical aging of dust is used in the analysis. The29

Sandu, Adrian

157

E-Print Network 3.0 - animal group-size distributions Sample...  

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

effects of learning and patch departure rules Summary: rule; optimal group size; simulation model; social foraging. Behav Ecol 16:352-357 (2005) Animals... of this mechanism for...

158

Sieveless particle size distribution analysis of particulate materials through computer vision  

SciTech Connect (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

159

Comparison of the bubble size distribution in silicate foams using 2-dimensional images and 3-dimensional x-ray microtomography  

SciTech Connect (OSTI)

Three silicate glasses were hydrated at high pressure and then heated at atmospheric pressure to exsolve the water into bubbles and create foams. The bubble size distribution in these foams was measured by x-ray microtomography on the GSECARS BM-13 beamline at the Advanced Photon Source. The bubble area distributions were measured in two dimensions using the image slices produced from the microtomography and the software ImageJ. The bubble volume distributions were measured from the three-dimensional tomographic images with the BLOB3D software. We found that careful analysis of the microtomography data in both two and three dimensions was necessary to avoid the physically unrealistic, experimental artifact of identifying and counting many small bubbles whose surfaces were not defined by a septum of glass. When this artifact was avoided the foams demonstrated power-law distributions of bubble sizes in both two and three dimensions. Conversion of the power-law exponents for bubble areas measured in two dimensions to exponents for bubble volumes usually agreed with the measured three dimensional volume exponents. Furthermore, the power-law distributions for bubble volumes typically agree with multiple theories of bubble growth, all of which yield an exponent of 1 for the cumulative bubble volume distribution. The measured bubble volume distributions with exponents near 0.3 can be explained by diffusive growth as proposed by other authors, but distributions with exponents near 1.4 remain to be explained and are the subject of continuing research on the effects of water concentration and melt viscosity on foaming behavior.

Robert, G.; Baker, D.R.; Rivers, M.L.; Allard, E.; Larocque, J. (McGill); (UC)

2005-02-03T23:59:59.000Z

160

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

Note: This page contains sample records for the topic "grain 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 representation of rainfall drop-size distribution and kinetic energy Hydrology and Earth System Sciences, 8(5), 10011007 (2004) EGU  

E-Print Network [OSTI]

-size distribution and kinetic energy Neil I. Fox Department of Soil, Environmental and Atmospheric Sciences373 Mc To relate observed rainfall rates (R) to the kinetic energy flux (E) that affects soil erosion component of drop velocity. Keywords: drop-size distribution, drop kinetic energy, soil erosion Introduction

Paris-Sud XI, Université de

162

Raindrop size distributions and radar reflectivity-rain rate relationships for radar hydrology Hydrology and Earth System Sciences, 5(4), 615627 (2001) EGS  

E-Print Network [OSTI]

Raindrop size distributions and radar reflectivity-rain rate relationships for radar hydrology 615 Hydrology and Earth System Sciences, 5(4), 615­627 (2001) © EGS Raindrop size distributions and radar reflectivity­rain rate relationships for radar hydrology* Remko Uijlenhoet1 Sub-department Water Resources

Boyer, Edmond

163

Importance of Size and Distribution of Ni Nanoparticles for the Hydrodeoxygenation of Microalgae Oil  

SciTech Connect (OSTI)

Improved synthetic approaches for preparing small-sized Ni nanoparticles (d=3 nm) supported on HBEA zeolite have been explored and compared with the traditional impregnation method. The formation of surface nickel silicate/aluminate involved in the two precipitation processes are inferred to lead to the stronger interaction between the metal and the support. The lower Brnsted acid concentrations of these two Ni/HBEA catalysts compared with the parent zeolite caused by the partial exchange of Brnsted acid sites by Ni2+ cations do not influence the hydrodeoxygenation rates, but alter the product selectivity. Higher initial rates and higher stability have been achieved with these optimized catalysts for the hydrodeoxygenation of stearic acid and microalgae oil. Small metal particles facilitate high initial catalytic activity in the fresh sample and size uniformity ensures high catalyst stability.

Song, Wenji; Zhao, Chen; Lercher, Johannes A.

2013-07-22T23:59:59.000Z

164

Inhalation toxicology of red and violet mixtures. Chamber concentration and particle-size distribution report  

SciTech Connect (OSTI)

An inhalation exposure facility was developed at the U.S. EPA, RTP, NC to conduct inhalation exposures of rodents and guinea pigs to dye mixtures used by the U.S. Army in the manufacture of smoke munitions. Initially, an evaluation of the prototype chamber aerosol homogeneity was conducted to determine the uniformity and reproducibility of the concentration and particle size of dye aerosol throughout the breathing zone of the test animals. The three dyes, DR11, SR1, and DB3, were chemically analyzed for purity and optically examined for size and shape. All pure dyes appeared to be stable at room temperature except DB3, which decomposes if not stored at 4 C. The particle size ranges varied for each pure dye and structures were either amorphous (azo dye) or crystalline (anthraquinone dyes). The bulk red and violet dye mixtures were analyzed for composition. The chemical analysis of the relative composition of each dye mixture, collected by cascade impactor sampling, revealed fractionation of the mixtures into component dyes.

Higuchi, M.A.; Davies, D.W.

1991-07-01T23:59:59.000Z

165

EVOLUTION OF DROPLET SIZE DISTRIBUTION AND AUTOCONVERSION PARAMETERIZATION IN TURBULENT CLOUDS  

E-Print Network [OSTI]

.S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United or reproduce the published form of this manuscript, or allow others to do so, for United States Government condition (Weibull distribution) determined by the balance between diffusion and drift. Monte Carlo

166

Development of laboratory and process sensors to monitor particle size distribution of industrial slurries (including shape characterization). Final technical report  

SciTech Connect (OSTI)

The overall goal of the Particle Size Distribution (PSD) sensor projects was to develop and commercialize a sensor system capable of particle analysis, in terms of size distributions, using concentrated suspensions at high solids concentrations. The early research was focused on application of ultrasonic spectroscopy of inorganic pigment slurries (e.g. titanium dioxide) commonly encountered on paper industry. During the project prototypes were tested in both academic and industrial laboratories. Work also involved successful field tests of the on-line prototype at a pigment manufacturing facility. Pen Kem continued the work at its cost beyond the initial funded period from March `92 to September `94. The first project (DE- FC05-88CE40684), which began in September 1988, culminated in a commercial laboratory instrument, Pen Kem AcoustoPhor {trademark} 8000, put on the market in June 1993. The follow-on project was aimed at investigation of shape and orientation effects on ultrasonic spectroscopy. A new cooperative agreement was awarded in September 1994 (DE-FC05-94CE40005) to develop shape characterization capabilities deemed critical by the clay industry. This follow-on project achieved following successes: A theoretical model was developed to account for the effects of size-dependent aspect ratios of spheroid particles under different orientations on ultrasound attenuation spectra of concentrated slurries. The theoretical model was confirmed by laboratory tests on kaolin slurries. An algorithm was developed to simulate evolution of particle orientation fields in simple squeezing flows.

Pendse, H.P.; Goetz, P.J.; Sharma, A.; Han, W; Bliss, T.C.

1996-10-01T23:59:59.000Z

167

HII regions in spiral galaxies: Size distribution, luminosity function, and new isochrone diagnostics of density wave kinematics  

E-Print Network [OSTI]

We investigate the relationship of the HII region luminosity function (HII LF) to the HII region size distribution and density wave triggering in grand-design spiral galaxies. We suggest that the differential nebular size distribution is described by a power law of slope ~ -4, with flattening at radii below ~ 130 pc. This contrasts with the conventional exponential description, but it is physically and quantitatively consistent with the typical observed value of -2 for the HII LF slope. We have developed an interactive code that computes spatial isochrones for the evolving loci of spiral density waves in disk galaxies. This allows comparison of the nebular spatial distribution with the spatial isochrones for simple rotation curve parameters. Our comparisons for four grand-design galaxies suggest that the corotation radius r_co coincides with the outer ends of the star-forming arms. This value for r_co yields the best spatial correspondence between the HII regions and the isochrones, and also appears to yield a coincidence between the Inner Lindblad Resonance with the radial onset of star formation in the arms. Thus, we suggest that isochrones offer a new, simple, and effective technique for determining r_co, and thus the spiral pattern speed. However, application of the isochrones also demonstrates that evolution of the nebular population is difficult to spatially isolate in these galaxies.

M. S. Oey; J. S. Parker; V. J. Mikles; X. Zhang

2003-07-10T23:59:59.000Z

168

Autonomous grain combine control system  

DOE Patents [OSTI]

A system for controlling a grain combine having a rotor/cylinder, a sieve, a fan, a concave, a feeder, a header, an engine, and a control system. The feeder of the grain combine is engaged and the header is lowered. A separator loss target, engine load target, and a sieve loss target are selected. Grain is harvested with the lowered header passing the grain through the engaged feeder. Separator loss, sieve loss, engine load and ground speed of the grain combine are continuously monitored during the harvesting. If the monitored separator loss exceeds the selected separator loss target, the speed of the rotor/cylinder, the concave setting, the engine load target, or a combination thereof is adjusted. If the monitored sieve loss exceeds the selected sieve loss target, the speed of the fan, the size of the sieve openings, or the engine load target is adjusted.

Hoskinson, Reed L.; Kenney, Kevin L.; Lucas, James R.; Prickel, Marvin A.

2013-06-25T23:59:59.000Z

169

When the expansion of finite-size corrections to hydrogen Lamb shift in moments of charge distribution breaks down  

E-Print Network [OSTI]

We point out a limitation of the standard way of accounting the finite-size effects, i.e., when the leading $[(Z\\alpha)^4]$ and subleading $[(Z\\alpha)^5]$ contributions to the Lamb shift are given by the mean-square radius and the third Zemach moment of the charge distribution. This limitation may have profound consequences for the interpretation of the "proton size puzzle". We find, for instance, that the de R\\'ujula toy model of the proton form factor does not resolve the puzzle as claimed, despite the large value of the third Zemach moment. Given the formula which does not rely on the radii expansion, we show how tiny (less than a hundredth of percent) changes in the proton electric form factor at a MeV scale would be able to explain the puzzle.

Hagelstein, Franziska

2015-01-01T23:59:59.000Z

170

The effect of gravel size fraction on the distribution coefficients of selected radionuclides radionuclides  

SciTech Connect (OSTI)

This manuscript addresses the consequences of the common practice of assuming that the gravel fraction of sediments does not participate in sorption reactions and thus sorption quantified by the distribution coefficient (Kd) construct can be estimated from laboratory tests on < 2mm fraction of sediments. As shown within the use of this common assumption can lead to inaccurate estimates of the mobility and sorption capacity of key radionuclides (Tc, U, and Np) at the Hanford Site where gravel dominates the lower Hanford formation and upper Ringold Formation. Batch sorption and column experiments showed that the distribution coefficient measured using only < 2mm fraction were not in agreement with those obtained from the bulk sediments depending on the radionuclide. The least reactive radionuclide, Tc showed the lowest effects from the presence of gravel. However, differences between measured Kds using < 2mm fractions of the sediment and the Kds measured on the bulk sediment were significant for strongly reactive radionuclides such as Np, especially on the sediment with gravel fractions that contained highly reactive sites. Highly reactive sites in the gravel fraction were attributed to the presence of Fe oxides coatings and/or reactive fracture faces on the gravel surfaces. Gravel correction factors that use the sum of the Kd,<2 mm and Kd,>2 mm values to estimate the Kd for the bulk sediment were found to best describe Kds for radionuclides on the bulk sediment. However, more detailed characterization of gravel surfaces should be also conducted to identify those gravels with higher reactive sorbents, if present. Gravel correction factors should be considered to predict precisely the sorption capacity of bulk sediments that contain more than 10% gravel and to estimate the mobility of contaminants in subsurface environments.

Um, Wooyong; Serne, R. Jeffrey; Last, George V.; Glossbrenner, Ellwood T.

2009-06-26T23:59:59.000Z

171

On the Size Distribution of Close-In Extrasolar Giant Planets  

E-Print Network [OSTI]

The precisions of extrasolar planet radius measurements are reaching the point at which meaningful and discriminatory comparisons with theoretical predictions are can be made. However, care must be taken to account for selection effects in the transit surveys that detect the transiting planets for which radius measurements are possible. Here I identify one such selection effect, such that the number of planets with radius R_p detected in a signal-to-noise ratio limited transit survey is proportional to R_p^alpha, with alpha~4-6. In the presence of a dispersion sigma in the intrinsic distribution of planet radii, this selection effect translates to bias b in the radii of observed planets. Detected planets are, on average, larger by a fractional amount b ~ alpha (sigma/)^2 relative to the mean radius of the underlying distribution. I argue that the intrinsic dispersion in planetary radii is likely to be in the range sigma = (0.05-0.13)R_J, where the lower bound is that expected theoretically solely from the variance in stellar insolation, and the upper bound is the 95% c.l. upper limit from the scatter in observed radii. Assuming an arbitrary but plausible value of sigma/~10%, and thus b~6%, I infer a mean intrinsic radius of close-in massive extrasolar planets of =(1.03+/-0.01)R_J. This value reinforces the case for HD209458b having an anomalously large radius, and may be inconsistent with coreless models of irradiated giant planets.

B. Scott Gaudi

2005-06-28T23:59:59.000Z

172

Improving Simulations of Fine Dust Surface Concentrations over the Western United States by Optimizing the Particle Size Distribution  

SciTech Connect (OSTI)

To improve estimates of remote contributions of dust to fine particulate matter (PM2.5) in the western United States, new dust particle size distributions (PSDs) based upon scale-invariant fragmentation theory (Kok_PSD) with constraints from in situ measurements (IMP_PSD) are implemented in a chemical transport model (GEOS-Chem). Compared to initial simulations, this leads to reductions in the mass of emitted dust particles with radii <1.8 mm by 40%-60%. Consequently, the root-mean-square error in simulated fine dust concentrations compared to springtime surface observations in the western United States is reduced by 67%-81%. The ratio of simulated fine to coarse PM mass is also improved, which is not achievable by reductions in total dust emissions. The IMP_PSD best represents the PSD of dust transported from remote sources and reduces modeled PM2.5 concentrations up to 5 mg/m3 over the western United States, which is important when considering sources contributing to nonattainment of air quality standards. Citation: Zhang, L., J. F. Kok, D. K. Henze, Q. Li, and C. Zhao (2013), Improving simulations of fine dust surface concentrations over the western United States by optimizing the particle size distribution, Geophys. Res. Lett., 40, 3270-3275, doi:10.1002/grl.50591.

Zhang, Li; Kok, Jasper F.; Henze, Daven; Li, Qinbin; Zhao, Chun

2013-06-28T23:59:59.000Z

173

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

SciTech Connect (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

174

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

SciTech Connect (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

175

Charging of dust grains in a nonequilibrium plasma of a stratified glow discharge  

SciTech Connect (OSTI)

A theoretical model is presented that describes the charging of dust grains in the positive plasma column of a stratified glow dc discharge in argon. A one-dimensional self-consistent model is used to obtain axial profiles of the electric field, as well as the electron energy distribution function along the axis of the discharge tube. Radial profiles of the electric field are determined in the ambipolar diffusion approximation. It is assumed that, in the radial direction, the electron distribution function depends only on the total electron energy. Two-dimensional distributions of the discharge plasma parameters are calculated and used to determine the potential and charge of a test dust grain at a certain point within the discharge and the electrostatic forces acting on it. It is shown that the grain charge distribution depends strongly on the nonequilibrium electron distribution function and on the nonuniform distribution of the electric field in a stratified glow discharge. A discussion is presented on the suspension of dust grains, the separation of grains by size in the discharge striations, and a possible mechanism for the onset of vortex dust motion at the edge of a dust cloud.

Sukhinin, G. I.; Fedoseev, A. V. [Russian Academy of Sciences, Kutateladze Institute of Thermophysics, Siberian Branch (Russian Federation)

2007-12-15T23:59:59.000Z

176

Characterization of secondary grain dust explosions  

E-Print Network [OSTI]

dust less than 106 um . . . ~ . . ~ ~ ~ ~ 27 4 Coulter Counter particle size distribution for wheat dust less than 106 um . 28 5 Coulter Counter particle size distribution for rice dust less than 106 um ~ 29 6 Coulter Counter particle size... distribution f' or wheat/sorghum dust, less than 106 um . 7 Coulter Counter particle size distribution for soybean dust less than 106 um 31 8 Coulter Counter particle size distribution for corn dust between 106 and. 250 um 9 Coulter Counter particle size...

Schulman, Cheryl Wendler

2012-06-07T23:59:59.000Z

177

JOURNAL DE PHYSIQUE Colloque C2, supplkment a u no 7, Tome 38, Juillet 1977, page C2-185 REMARKS ON THE SIZE DISTRIBUTION FUNCTION OF ULTRAFINE  

E-Print Network [OSTI]

. - The results of an detailed analysis of experimental size distributions of particle samples prepared by the gas tvaporation et condensation en gaz inerte (GET). En tenant compte des deux mbcanismes de croissance par distribution of ultrafine metal particles prepared by the gas evaporation technique (GET) can be ascribed

Boyer, Edmond

178

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

SciTech Connect (OSTI)

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

179

Simultaneous Retrieval of Effective Refractive Index and Density from Size Distribution and Light Scattering Data: Weakly-Absorbing Aerosol  

SciTech Connect (OSTI)

We propose here a novel approach for retrieving in parallel the effective density and real refractive index of weakly absorbing aerosol from optical and size distribution measurements. Here we define weakly absorbing as aerosol single-scattering albedos that exceed 0.95 at 0.5 um.The required optical measurements are the scattering coefficient and the hemispheric backscatter fraction, obtained in this work from an integrating nephelometer. The required size spectra come from a Scanning Mobility Particle Sizer and an Aerodynamic Particle Sizer. The performance of this approach is first evaluated using a sensitivity study with synthetically generated but measurement-related inputs. The sensitivity study reveals that the proposed approach is robust to random noise; additionally the uncertainties of the retrieval are almost linearly proportional to the measurement errors, and these uncertainties are smaller for the real refractive index than for the effective density. Next, actual measurements are used to evaluate our approach. These measurements include the optical, microphysical, and chemical properties of weakly absorbing aerosol which are representative of a variety of coastal summertime conditions observed during the Two-Column Aerosol Project (TCAP; http://campaign.arm.gov/tcap/). The evaluation includes calculating the root mean square error (RMSE) between the aerosol characteristics retrieved by our approach, and the same quantities calculated using the conventional volume mixing rule for chemical constituents. For dry conditions (defined in this work as relative humidity less than 55%) and sub-micron particles, a very good (RMSE~3%) and reasonable (RMSE~28%) agreement is obtained for the retrieved real refractive index (1.490.02) and effective density (1.680.21), respectively. Our approach permits discrimination between the retrieved aerosol characteristics of sub-micron and sub-10micron particles. The evaluation results also reveal that the retrieved density and refractive index tend to decrease with an increase of the relative humidity.

Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Berg, Larry K.; Shilling, John E.; Flynn, Connor J.; Mei, Fan; Jefferson, Anne

2014-10-01T23:59:59.000Z

180

Evaluation of the modified Anderson sampler for determining particle size distributions and respirable concentrations of particulate matter present in the working environment of cottonseed oil mills  

E-Print Network [OSTI]

EVALUATION OF THE MODIFIED ANDERSON SAMPLER FOR DETERMINING PARTICLE SIZE DISTRIBUTIONS AND RESPIRABLE CONCENTRATIONS OF PARTICULATE MATTER PRESENT IN THE WORKING ENVIRONMENT OF COTTONSEED OIL MILLS A Thesis by STANLEY WAYNE MATLOCK Submitted... to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1976 Major Subject: Agricultural Engineering FVALUATION OF THE MODIFIED ANDERSON SAMPLER FOR DETERMINING PARTICLE SIZE...

Matlock, Stanley Wayne

1976-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

A b s t r a c t. The paper presents a comparison of particle size distributions of 23 mineral soils from SE Poland obtained by the  

E-Print Network [OSTI]

fraction (sand). K e y w o r d s: mineral soils, particle size distribution, laser diffraction, areometric soils (Orthic Luvisols) and 1 black earth (Mollic Gleysol). Air-dry soil samples were sieved on 2 mm was prepared using distilled water as the liquid phase. To improve the credibility of results, the measurement

Ahmad, Sajjad

182

Modeling kinetic partitioning of secondary organic aerosol and size distribution dynamics: representing effects of volatility, phase state, and particle-phase reaction  

SciTech Connect (OSTI)

Evidence is mounting that the majority of the climatically active aerosols are produced through the growth of smaller particles via secondary organic aerosol (SOA) formation from gas-to-particle conversion of anthropogenic and biogenic volatile organic compounds (VOCs). The timescale of SOA partitioning and the associated size distribution dynamics are expected to depend on the gas-phase oxidation of the precursor VOCs and their products, volatility of these organic solutes, composition and phase state of the pre-existing particles, and diffusivity and reactivity of the solute within the particle phase. This paper describes a new framework for modeling kinetic gas-particle partitioning of SOA, with an analytical treatment for the diffusion-reaction process within the particle phase. The formulation is amenable for eventual use in regional and global climate models, although it currently awaits implementation of the actual particle-phase reactions that are important for SOA formation. In the present work, the model is applied to investigate the competitive growth dynamics of the Aitken and accumulation mode particles while the Kelvin effect and coagulation are neglected for simplicity. The timescale of SOA partitioning and evolution of number and composition size distributions are evaluated for a range of solute volatilities (C*), particle-phase bulk diffusivities (Db), and particle-phase reactivity, as exemplified by a pseudo-first-order rate constant (kc). Results show that irreversible condensation of non-volatile organic vapors (equivalent to ) produces significant narrowing of the size distribution. At the other extreme, non-reactive partitioning of semi-volatile organic vapors is volume-controlled in which the final (equilibrium) size distribution simply shifts to the right on the diameter axis while its shape remains unchanged. However, appreciable narrowing of the size distribution may occur when the pre-existing particles are highly viscous semi-solids such that small particles reach quasi-equilibrium much faster than the large ones. In the case of reactive partitioning (finite ), the size distribution experiences permanent narrowing, which is especially pronounced for Db < 10-13 cm2 s-1 and kc > 0.01 s-1. As a result, both number and composition size distributions are needed to effectively constrain and evaluate the next generation of SOA models that treat phase state thermodynamics, particle-phase diffusion and particle-phase chemical reactions.

Zaveri, Rahul A.; Easter, Richard C.; Shilling, John E.; Seinfeld, J. H.

2014-05-27T23:59:59.000Z

183

Effect of Grain Boundaries on Krypton Segregation Behavior in Irradiated Uranium Dioxide  

SciTech Connect (OSTI)

Fission products, such as krypton (Kr), are known to be insoluble within UO2, segregating towards grain boundaries, eventually leading to a lowering of the thermal conductivity and fuel swelling. Recent computational studies have identified that differences in grain boundary structure have a significant effect on the segregation behavior of fission products. However, experimental work supporting these simulations is lacking. Atom probe tomography was used to measure the Kr distribution across grain boundaries in UO2. Polycrystalline depleted-UO2 samples was irradiated with 0.7 and 1.8 MeV Kr-ions and annealed to 1000, 1300, and 1600C for 1 hour to produce a Kr-bubble dominated microstructure. The results of this work indicate a strong dependence of Kr concentration as a function of grain boundary structure. Temperature also influences grain boundary chemistry with greater Kr concentration evident at higher temperatures, resulting in a reduced Kr concentration in the bulk. While Kr migration is active at elevated temperatures, no changes in grain size or texture were observed in the irradiated samples.

Billy Valderrama; Lingfeng He; Hunter B. Henderson; Janne Pakarinen; Brian Jaques; Jian Gan; Darryl P. Butt; Todd R. Allen; Michele V. Manuel

2015-01-01T23:59:59.000Z

184

DUST PROPERTIES AND DISK STRUCTURE OF EVOLVED PROTOPLANETARY DISKS IN Cep OB2: GRAIN GROWTH, SETTLING, GAS AND DUST MASS, AND INSIDE-OUT EVOLUTION  

SciTech Connect (OSTI)

We present Spitzer/Infrared Spectrograph spectra of 31 T Tauri stars (TTS) and IRAM/1.3 mm observations for 34 low- and intermediate-mass stars in the Cep OB2 region. Including our previously published data, we analyze 56 TTS and 3 intermediate-mass stars with silicate features in Tr 37 ({approx}4 Myr) and NGC 7160 ({approx}12 Myr). The silicate emission features are well reproduced with a mixture of amorphous (with olivine, forsterite, and silica stoichiometry) and crystalline grains (forsterite, enstatite). We explore grain size and disk structure using radiative transfer disk models, finding that most objects have suffered substantial evolution (grain growth, settling). About half of the disks show inside-out evolution, with either dust-cleared inner holes or a radially dependent dust distribution, typically with larger grains and more settling in the innermost disk. The typical strong silicate features nevertheless require the presence of small dust grains, and could be explained by differential settling according to grain size, anomalous dust distributions, and/or optically thin dust populations within disk gaps. M-type stars tend to have weaker silicate emission and steeper spectral energy distributions than K-type objects. The inferred low dust masses are in a strong contrast with the relatively high gas accretion rates, suggesting global grain growth and/or an anomalous gas-to-dust ratio. Transition disks in the Cep OB2 region display strongly processed grains, suggesting that they are dominated by dust evolution and settling. Finally, the presence of rare but remarkable disks with strong accretion at old ages reveals that some very massive disks may still survive to grain growth, gravitational instabilities, and planet formation.

Sicilia-Aguilar, Aurora; Henning, Thomas; Dullemond, Cornelis P.; Bouwman, Jeroen; Sturm, Bernhard [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Patel, Nimesh [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Juhasz, Attila, E-mail: sicilia@mpia.de, E-mail: aurora.sicilia@uam.es [Leiden Observatory, Niels Bohrweg 2, NL-2333 CA Leiden (Netherlands)

2011-11-20T23:59:59.000Z

185

Final Report: Property Improvement in CZT via Modeling and Processing Innovations Te-particles in vertical gradient freeze CZT: Size and Spatial Distributions and Constitutional Supercooling  

SciTech Connect (OSTI)

A section of a vertical gradient freeze CZT boule approximately 2100-mm3 with a planar area of 300-mm2 was prepared and examined using transmitted IR microscopy at various magnifications to determine the three-dimensional spatial and size distributions of Te-particles over large longitudinal and radial length scales. The boule section was approximately 50-mm wide by 60-mm in length by 7-mm thick and was doubly polished for TIR work. Te-particles were imaged through the thickness using extended focal imaging to locate the particles in thickness planes spaced 15-m apart and then in plane of the image using xy-coordinates of the particle center of mass so that a true three dimensional particle map was assembled for a 1-mm by 45-mm longitudinal strip and for a 1-mm by 50-mm radial strip. Te-particle density distributions were determined as a function of longitudinal and radial positions in these strips, and treating the particles as vertices of a network created a 3D image of the particle spatial distribution. Te-particles exhibited a multi-modal log-normal size density distribution that indicated a slight preference for increasing size with longitudinal growth time, while showing a pronounced cellular network structure throughout the boule that can be correlated to dislocation network sizes in CZT. Higher magnification images revealed a typical Rayleigh-instability pearl string morphology with large and small satellite droplets. This study includes solidification experiments in small crucibles of 30:70 mixtures of Cd:Te to reduce the melting point below 1273 K (1000?C). These solidification experiments were performed over a wide range of cooling rates and clearly demonstrated a growth instability with Te-particle capture that is suggested to be responsible for one of the peaks in the size distribution using size discrimination visualization. The results are discussed with regard to a manifold Te-particle genesis history as 1) Te-particle direct capture from melt-solid growth instabilities, 2) Te-particle formation from dislocation core diffusion and the formation and breakup of Te-tubes, and 3) Te-particle formation due to classical nucleation and growth as precipitates.

Henager, Charles H.; Alvine, Kyle J.; Bliss, Mary; Riley, Brian J.; Stave, Jean A.

2014-10-01T23:59:59.000Z

186

Modeling of stress distributions on the microstructural level in Alloy 600  

SciTech Connect (OSTI)

Stress distribution in a random polycrystalline material (Alloy 600) was studied using a topologically correct microstructural model. Distributions of von Mises and hydrostatic stresses at the grain vertices, which could be important in intergranular stress corrosion cracking, were analyzed as functions of microstructure, grain orientations and loading conditions. Grain size, shape, and orientation had a more pronounced effect on stress distribution than loading conditions. At grain vertices the stress concentration factor was higher for hydrostatic stress (1.7) than for von Mises stress (1.5). The stress/strain distribution in the volume (grain interiors) is a normal distribution and does not depend on the location of the studied material volume i.e., surface vs/bulk. The analysis of stress distribution in the volume showed the von Mises stress concentration of 1.75 and stress concentration of 2.2 for the hydrostatic pressure. The observed stress concentration is high enough to cause localized plastic microdeformation, even when the polycrystalline aggregate is in the macroscopic elastic regime. Modeling of stresses and strains in polycrystalline materials can identify the microstructures (grain size distributions, texture) intrinsically susceptible to stress/strain concentrations and justify the correctness of applied stress state during the stress corrosion cracking tests. Also, it supplies the information necessary to formulate the local failure criteria and interpret of nondestructive stress measurements.

Kozaczek, K.J. [Oak Ridge National Lab., TN (United States); Petrovic, B.G.; Ruud, C.O. [Pennsylvania State Univ., University Park, PA (United States); Mcllree, A.R. [Electric Power Research Inst., Palo Alto, CA (United States)

1995-04-01T23:59:59.000Z

187

Study of catalytic diffusion in coal. Final report for 1983/1984 SOMED Project. [Determination of pore (hole) size and pore shape distribution  

SciTech Connect (OSTI)

The purpose of our studies is to determine the pore (hole) size and pore shape distribution in standard bituminous coal samples from various Alabama coal seams such as that of the Mary Lee, Black Creek and Pratt during and after swelling of the coal with different solvents at various temperatures. These samples come from the Penn State Coal Sample Bank at Pennsylvania State University Coal Research Section and from Alabama's Mineral Industries. Methods have been developed in the laboratory whereby free radical probes of varying sizes can be diffused into the coal under various conditions. These probes can be detected and the environment surrounding the probes can be deduced by electron paramagnetic resonance (EPR) methods. To date, we have found that not only can the shape and size of the pores be determined, but that the size distribution varies from one bituminous coal seam to another, even for coal of the same rank, suggesting a different optimal catalyst should be used for each seam. The effect of oxygen on the coal samples during grinding has been studied; however, the free radical technique appears to be insensitive to the presence of oxygen effects. It is our goal to determine the structural differences between various bituminous coals. 9 references, 9 figures, 1 table.

Kispert, L.D.

1984-09-01T23:59:59.000Z

188

Grain Refinement of Permanent Mold Cast Copper Base Alloys  

SciTech Connect (OSTI)

Grain refinement is a well established process for many cast and wrought alloys. The mechanical properties of various alloys could be enhanced by reducing the grain size. Refinement is also known to improve casting characteristics such as fluidity and hot tearing. Grain refinement of copper-base alloys is not widely used, especially in sand casting process. However, in permanent mold casting of copper alloys it is now common to use grain refinement to counteract the problem of severe hot tearing which also improves the pressure tightness of plumbing components. The mechanism of grain refinement in copper-base alloys is not well understood. The issues to be studied include the effect of minor alloy additions on the microstructure, their interaction with the grain refiner, effect of cooling rate, and loss of grain refinement (fading). In this investigation, efforts were made to explore and understand grain refinement of copper alloys, especially in permanent mold casting conditions.

M.Sadayappan; J.P.Thomson; M.Elboujdaini; G.Ping Gu; M. Sahoo

2005-04-01T23:59:59.000Z

189

Power law and exponential ejecta size distributions from the dynamic fragmentation of shock-loaded Cu and Sn metals under melt conditions  

SciTech Connect (OSTI)

Large scale molecular dynamics (MD) simulations are performed to study and to model the ejecta production from the dynamic fragmentation of shock-loaded metals under melt conditions. A generic 3D crystal in contact with vacuum containing about 10{sup 8} atoms and with a sinusoidal free surface roughness is shock loaded so as to undergo a solid-liquid phase change on shock. The reflection of the shock wave at the interface metal/vacuum gives rise to the ejection of 2D jets/sheets of atoms (Richtmyer-Meshkov instabilities in the continuum limit), which develop and break up, forming ejecta (fragments) of different volumes (or mass). The fragmentation process is investigated by analyzing the evolution of the resulting volume distribution of the ejecta as a function of time. Two metals are studied (Cu and Sn) and the amplitude of the roughness is varied. The simulations show that the associated distributions exhibit a generic behavior with the sum of two distinct terms of varying weight, following the expansion rate of the jets: in the small size limit, the distribution obeys a power law dependence with an exponent equal to 1.15??0.08; and in the large size limit, it obeys an exponential form. These two components are interpreted, with the help of additional simple simulations, as the signature of two different basic mechanisms of fragmentation. The power law dependence results from the fragmentation of a 2D network of ligaments arranged following a fractal (scale free) geometry and generated when the sheets of liquid metal expand and tear. The exponential distribution results from a 1D Poisson fragmentation process of the largest ligaments previously generated. Unlike the power law distribution, it is governed by a characteristic length scale, which may be provided by energy balance principle.

Durand, O.; Soulard, L. [CEA, DAM, DIF, F-91297 Arpajon (France)

2013-11-21T23:59:59.000Z

190

Do grain boundaries in nanophase metals slide?  

SciTech Connect (OSTI)

Nanophase metallic materials show a maximum in strength as grain size decreases to the nano scale, indicating a break down of the Hall-Petch relation. Grain boundary sliding, as a possible accommodation mechanisms, is often the picture that explain computer simulations results and real experiments. In a recent paper, Bringa et al. Science 309, 1838 (2005), we report on the observation of an ultra-hard behavior in nanophase Cu under shock loading, explained in terms of a reduction of grain boundary sliding under the influence of the shock pressure. In this work we perform a detailed study of the effects of hydrostatic pressure on nanophase Cu plasticity and find that it can be understood in terms of pressure dependent grain boundary sliding controlled by a Mohr-Coulomb law.

Bringa, E M; Leveugle, E; Caro, A

2006-10-27T23:59:59.000Z

191

PROGRESS ON LARGE GRAIN AND SINGLE GRAIN NIOBIUM: INGOTS AND SHEET AND REVIEW OF PROGRESS ON LARGE GRAIN AND SINGLE GRAIN NIOBIUM CAVITIES  

SciTech Connect (OSTI)

Large grain and single crystal niobium has been proposed several years ago as an alternative material to poly-crystalline niobium for superconducting cavities, exhibiting potential advantages such as stream-lined procedures, reduced costs and better reproducibility in performance. Several major laboratories have investigated the use of large grain and single crystal material in the past years and the niobium producing industry has responded in providing ingot material with enlarged grain sizes. Besides a large number of single cell and multi-cell cavities from large grain niobium, several single crystal cavities have been fabricated and tested with good performances. This contribution will review the progress since the SRF workshop in 2005 in material processing and handling and in cavity performances.

Peter Kneisel

2008-02-12T23:59:59.000Z

192

High-strain-rate nanoindentation behavior of fine-grained magnesium alloys  

E-Print Network [OSTI]

The effects of temperature and alloying elements on deformation in the high-strain-rate regime were investigated by testing fine-grained magnesium alloys with an average grain size of 2 ? 3 ?m by a nanoindentation technique. ...

Somekawa, Hidetoshi

193

Dynamic simulation of a circulating fluidized bed boiler of low circulating ratio with wide particle size distributions  

SciTech Connect (OSTI)

A steady state model of a coal fired CFB boiler considering the hydrodynamics, heat transfer and combustion is presented. This model predicts the flue gas temperature, the chemical gas species (O{sub 2}, H{sub 2}O, CO, CO{sub 2} and SO{sub 2}) and char concentration distributions in both the axial and radial location along the furnace including the bottom and upper portion. The model was validated against experimental data generated in a 35 t/h commercial CFB boiler with low circulating ratio.

Lu Huilin; Yang Lidan; Bie Rushan; Zhao Guangbo

1999-07-01T23:59:59.000Z

194

Grain refinement and partitioning of impurities in the grain boundaries of a colloidal polycrystal  

E-Print Network [OSTI]

We study the crystallization of a colloidal model system in presence of secondary nanoparticles acting as impurities. Using confocal microscopy, we show that the nanoparticles segregate in the grain boundaries of the colloidal polycrystal. We demonstrate that the texture of the polycrystal can be tuned by varying independently the nanoparticle volume fraction and the crystallization rate, and quantify our findings using standard models for the nucleation and growth of crystalline materials. Remarkably, we find that the efficiency of the segregation of the nanoparticles in the grain-boundaries is determined solely by the typical size of the crystalline grains.

Neda Ghofraniha; Elisa Tamborini; Julian Oberdisse; Luca Cipelletti; Laurence Ramos

2012-03-29T23:59:59.000Z

195

Influence of Aluminum Content on Grain Refinement and Strength of AZ31 Magnesium GTA Weld Metal  

SciTech Connect (OSTI)

The goal is to characterize the effect of Al content on AZ31 weld metal, the grain size and strength, and examine role of Al on grain refinement. The approach is to systematically vary the aluminum content of AZ31 weld metal, Measure average grain size in weld metal, and Measure cross-weld tensile properties and hardness. Conclusions are that: (1) increased Al content in AZ31 weld metal results in grain refinement Reason: higher undercooling during solidification; (2) weld metal grain refinement resulted in increased strength & hardness Reason: grain boundary strengthening; and (3) weld metal strength can be raised to wrought base metal levels.

Babu, N. Kishore [Singapore Institute of Manufacturing Technology; Cross, Carl E. [Los Alamos National Laboratory

2012-06-28T23:59:59.000Z

196

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  

SciTech Connect (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

197

Preliminary investigation of the role that DMS (dimethyl sulfide) and cloud cycles play in the formation of the aerosol size distribution. Interim report  

SciTech Connect (OSTI)

A series of experiments designed to study the production of new particulate matter by photolysis of dimethyl sulfide (DMS) and the effect that nonprecipitating clouds have on the aerosol size distributions were carried out in Calspan Corporation's 600 cum environmental chamber during January and February 1986. The results show that DMS, the most-abundant natural source of sulfur, is photooxidized to some product of low volatility that can form new particles by homogeneous nucleation or condense on existing aerosols causing them to grow. To explain these observations, a theoretical study of the nucleation properties of methane sulfonic acid (MSA) was undertaken. The nucleation thresholds, calculated using thermodynamic data for MSA, show that at 70% RH, and MSA concentration of only 0.006 ppb will result in a supersaturated environment in which MSA will condense on preexisting particles larger than 0.02-micron radius. If the MSA concentrations increase to 30 ppb, then spontaneous formation of MSA solution droplets occurs by homogeneous binary nucleation. Simulations of the evolution of the size distribution observed for the DMS irradiation experiments with a dynamic aerosol model that includes the effects of coagulation, growth by condensation, and deposition to the walls of the chamber, yield results that are in excellent agreement with the observed evolution.

Hoppel, W.A.; Fitzgerald, J.W.; Frick, G.M.; Larson, R.E.; Wattle, B.J.

1987-07-29T23:59:59.000Z

198

CURVED WALLS: GRAIN GROWTH, SETTLING, AND COMPOSITION PATTERNS IN T TAURI DISK DUST SUBLIMATION FRONTS  

SciTech Connect (OSTI)

The dust sublimation walls of disks around T Tauri stars represent a directly observable cross-section through the disk atmosphere and midplane. Their emission properties can probe the grain size distribution and composition of the innermost regions of the disk, where terrestrial planets form. Here we calculate the inner dust sublimation wall properties for four classical T Tauri stars with a narrow range of spectral types and inclination angles and a wide range of mass accretion rates to determine the extent to which the walls are radially curved. Best fits to the near- and mid-IR excesses are found for curved, two-layer walls in which the lower layer contains larger, hotter, amorphous pyroxene grains with Mg/(Mg+Fe) = 0.6 and the upper layer contains submicron, cooler, mixed amorphous olivine and forsterite grains. As the mass accretion rates decrease from 10{sup 8} to 10{sup 10} M{sub ?} yr{sup 1}, the maximum grain size in the lower layer decreases from ?3 to 0.5 ?m. We attribute this to a decrease in fragmentation and turbulent support for micron-sized grains with decreasing viscous heating. The atmosphere of these disks is depleted of dust with dust-gas mass ratios 1 10{sup 4} of the interstellar medium (ISM) value, while the midplane is enhanced to eight times the ISM value. For all accretion rates, the wall contributes at least half of the flux in the optically thin 10 ?m silicate feature. Finally, we find evidence for an iron gradient in the disk, suggestive of that found in our solar system.

McClure, M. K.; Calvet, N.; Hartmann, L.; Ingleby, L. [Department of Astronomy, The University of Michigan, 500 Church Street, 830 Dennison Building., Ann Arbor, MI 48109 (United States); D'Alessio, P. [Centro de Radioastronoma y Astrofsica, Universidad Nacional Autnoma de Mxico, 58089 Morelia, Michoacn (Mexico); Espaillat, C. [Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Sargent, B. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Watson, D. M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Hernndez, J., E-mail: melisma@umich.edu, E-mail: ncalvet@umich.edu, E-mail: lhartm@umich.edu, E-mail: lingleby@umich.edu, E-mail: p.dalessio@astrosmo.unam.mx, E-mail: cespaillat@cfa.harvard.edu, E-mail: baspci@rit.edu, E-mail: dmw@pas.rochester.edu, E-mail: hernandj@cida.ve [Centro de Investigaciones de Astronoma (CIDA), Mrida 5101-A (Venezuela, Bolivarian Republic of)

2013-10-01T23:59:59.000Z

199

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

SciTech Connect (OSTI)

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

Mansour, A.; Chigier, N.

1993-12-01T23:59:59.000Z

200

Comparative study of genotoxicity and tissue distribution of nano and micron sized iron oxide in rats after acute oral treatment  

SciTech Connect (OSTI)

Though nanomaterials (NMs) are being utilized worldwide, increasing use of NMs have raised concerns over their safety to human health and environment. Iron oxide (Fe{sub 2}O{sub 3}) NMs have important applications. The aim of this study was to assess the genotoxicity of Fe{sub 2}O{sub 3}-30 nm and Fe{sub 2}O{sub 3}-bulk in female Wistar rats. Fe{sub 2}O{sub 3}-30 nm was characterized by using transmission electron microscopy, dynamic light scattering, laser Doppler velocimetry and surface area analysis. The rats were treated orally with the single doses of 500, 1000, 2000 mg/kg bw of Fe{sub 2}O{sub 3}-30 nm and Fe{sub 2}O{sub 3} bulk. The genotoxicity was evaluated at 6, 24, 48 and 72 h by the comet assay in leucocytes, 48 and 72 h by micronucleus test (MNT) in peripheral blood cells, 18 and 24 h by chromosomal aberration (CA) assay and 24 and 48 h by MNT in bone marrow cells. The biodistribution of iron (Fe) was carried out at 6, 24, 48 and 72 h after treatment in liver, spleen, kidney, heart, brain, bone marrow, urine and feces by using atomic absorption spectrophotometry. The % tail DNA, frequencies of micronuclei and CAs were statistically insignificant (p > 0.05) at all doses. These results suggest that Fe{sub 2}O{sub 3}-30 nm and Fe{sub 2}O{sub 3}-bulk was not genotoxic at the doses tested. Bioavailability of Fe was size and dose dependent in all the tissues from the groups exposed to Fe{sub 2}O{sub 3}-30 nm. Fe{sub 2}O{sub 3} NMs were able to enter in the organs and the rats are biocompatible with much higher concentration of Fe. However, the accumulated Fe did not cause significant genotoxicity. This study provides additional knowledge about the toxicology of Fe{sub 2}O{sub 3} NMs. -- Highlights: ? Fe{sub 2}O{sub 3}-30 nm and Fe{sub 2}O{sub 3}-bulk were orally administered to rats with single doses. ? The nano and bulk Fe{sub 2}O{sub 3} showed insignificant results with MNT, comet and CA assays. ? The bulk was excreted via feces whereas the NMs were found both in urine and feces. ? The NMs mainly accumulated in the liver, spleen, kidney, heart and bone marrow. ? However the accumulated Fe did not cause significant genotoxicological effects.

Singh, Shailendra Pratap; Rahman, M.F.; Murty, U.S.N.; Mahboob, M.; Grover, Paramjit, E-mail: paramgrover@gmail.com

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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.


201

Fine Grained Robotics  

E-Print Network [OSTI]

Fine grained robotics is the idea of solving problems utilizing multitudes of very simple machines in place of one large complex entity. Organized in the proper way, simple machines and simple behaviors can lead to emergent ...

Flynn, Anita M.

202

Small Grains for Forage.  

E-Print Network [OSTI]

for both early and sustained production. Further testing of these varieties is underway. Otller varieties may be used satisfactorily, but the ones named have given the most consistent performance. Small grain varieties differ in growth habit, some... carried out at Crys- tal City to determine the import- ance of stage of growth at first clipping and frequency of clipping on small grain forage yields. These results are presented in Table 1. Under both field ancl greenhouse conditions...

Holt, Ethan C.

1959-01-01T23:59:59.000Z

203

Estimating Corn Grain Yields  

E-Print Network [OSTI]

can collect samples from a corn field and use this data to calculate the yield estimate. An interactive grain yield calculator is provided in the Appendix of the pdf version of this publication. The calculator is also located in the publication.... Plan and prepare for sample and data collection. 2. Collect field samples and record data. 3. Analyze the data using the interactive grain yield calculator in the Appendix. Plan and prepare for sample and data collection Predetermine sample locations...

Blumenthal, Jurg M.; Thompson, Wayne

2009-06-12T23:59:59.000Z

204

Computer simulation of grain growth with mobile particles  

SciTech Connect (OSTI)

The authors have studied the influence of mobile particles on grain growth kinetics. Three time regimes are evident in the observed coarsening. Initially, most grains grow unhindered by particles, with a growth exponent close to 1/2. As with static impurities, once the mean grain size approaches the average inter-particle separation the microstructure becomes effectively pinned. With mobile impurities, however, the loaded grain boundaries eventually resume their motion. The depinning time is observed to be independent of particle concentration. The observed kinetic behavior, growth exponents, and depinning time are in agreement with a simple theoretical model with different mobilities for boundaries with and without attached particles.

Hassold, G.N. [GMI Engineering and Management Inst., Flint, MI (United States). Dept. of Science and Mathematics] [GMI Engineering and Management Inst., Flint, MI (United States). Dept. of Science and Mathematics; Srolovitz, D.J. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering] [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering

1995-05-15T23:59:59.000Z

205

FORMATION OF SiC GRAINS IN PULSATION-ENHANCED DUST-DRIVEN WIND AROUND CARBON-RICH ASYMPTOTIC GIANT BRANCH STARS  

SciTech Connect (OSTI)

We investigate the formation of silicon carbide (SiC) grains in the framework of dust-driven wind around pulsating carbon-rich asymptotic giant branch (C-rich AGB) stars to reveal not only the amount but also the size distribution. Two cases are considered for the nucleation process: one is the local thermal equilibrium (LTE) case where the vibration temperature of SiC clusters T{sub v} is equal to the gas temperature as usual, and another is the non-LTE case in which T{sub v} is assumed to be the same as the temperature of small SiC grains. The results of the hydrodynamical calculations for a model with stellar parameters of mass M{sub *} = 1.0 M{sub Sun }, luminosity L{sub *} = 10{sup 4} L{sub Sun }, effective temperature T{sub eff} = 2600 K, C/O ratio = 1.4, and pulsation period P = 650 days show the following: in the LTE case, SiC grains condense in accelerated outflowing gas after the formation of carbon grains, and the resulting averaged mass ratio of SiC to carbon grains of {approx}10{sup -8} is too small to reproduce the value of 0.01-0.3, which is inferred from the radiative transfer models. On the other hand, in the non-LTE case, the formation region of the SiC grains is more internal and/or almost identical to that of the carbon grains due to the so-called inverse greenhouse effect. The mass ratio of SiC to carbon grains averaged at the outer boundary ranges from 0.098 to 0.23 for the sticking probability {alpha}{sub s} = 0.1-1.0. The size distributions with the peak at {approx}0.2-0.3 {mu}m in radius cover the range of size derived from the analysis of the presolar SiC grains. Thus, the difference between the temperatures of the small cluster and gas plays a crucial role in the formation process of SiC grains around C-rich AGB stars, and this aspect should be explored for the formation process of dust grains in astrophysical environments.

Yasuda, Yuki; Kozasa, Takashi, E-mail: yuki@antares-a.sci.hokudai.ac.jp [Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan)

2012-02-01T23:59:59.000Z

206

Effect of coal type, residence time, and combustion configuration on the submicron aerosol composition and size distribution from pulverized coal combustion  

SciTech Connect (OSTI)

Pulverized samples of Utah bituminous, Beulah (North Dakota) low Na lignite, Deulah high Na lignite and Texas (San Miguel) lignite coals were burned at a rate of 2.5 kg/hr in a laboratory furnace under various (overall fuel lean) combustion conditions. Particle size distributions (PSD) and size segregated particle filter samples were taken at various positions within the convection section. Temperature and gas concentrations were measured throughout. The evolution of the submicron PSD within the convection section for the four coals was similar, although the location of the initial particle mode at the convection section inlet varied with coal type. While stage combustion of the Utah bituminous coal had a variable effect on the volume of submicron aerosol produced, staged combustion of two of the three lignites (Beulah low Na and Texas) caused a definite increase in the submicron aerosol volume. Chemical analysis of the size segregated particle samples show the trace elements, As, Pb, Zn, and the major elements, Na and K to be enriched in the submicron aerosol. Auger depth profiles show these small particles to be comprised of a core enriched in Fe, Si, Ca and Mg and surface layers enriched in Na and K. These results point to a mechanism of homogeneous nucleation of low vapor pressure species followed by successive layering of progressively more volatile species. Volatile species are enriched in the submicron aerosol due to the large surface areas provided. Modeling efforts show that while coagulation may be the dominant mechanism to describe the aerosol evolving within the convection section, it cannot be used solely to predict the PSD. Another mechanism, presumably surface area dependent growth (condensation) must be included.

Linak, W.P.

1985-01-01T23:59:59.000Z

207

ARM - Measurement - Particle size distribution  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Relatedcontent ARMnumber concentration ARM Data Discovery

208

Grains, Water Introduction  

E-Print Network [OSTI]

Grains, Water & Wet Sand Onno Bokhove Introduction Dry Granular Chute Flows: Cantilever Water Waves: Bores Near the Shore Surf Induced Sand Dynamics Discussion Dry Granular Flows, Water Waves & Surf, Water & Wet Sand Onno Bokhove Introduction Dry Granular Chute Flows: Cantilever Water Waves: Bores Near

Wirosoetisno, Djoko

209

Influence of Alloy and Solidification Parameters on Grain Refinement in Aluminum Weld Metal due to Inoculation  

SciTech Connect (OSTI)

The goals are: (1) Establish how much Ti/B grain refiner is need to completely refine aluminum weld metal for different alloys and different welding conditions; (2) Characterize how alloy composition and solidification parameters affect weld metal grain refinement; and (3) Apply relevant theory to understand observed behavior. Conclusions are: (1) additions of Ti/B grain refiner to weld metal in Alloys 1050, 5083, and 6082 resulted in significant grain refinement; (2) grain refinement was more effective in GTAW than LBW, resulting in finer grains at lower Ti content - reason is limited time available for equiaxed grain growth in LBW (inability to occlude columnar grain growth); (3) welding travel speed did not markedly affect grain size within GTAW and LBW clusters; and (4) application of Hunt CET analysis showed experimental G to be on the order of the critical G{sub CET}; G{sub CET} was consistently higher for GTAW than for LBW.

Schempp, Philipp [BAM, Germany; Tang, Z. [BIAS, Germany; Cross, Carl E. [Los Alamos National Laboratory; Seefeld, T. [BIAS, Germany; Pittner, A. [BAM, Germany; Rethmeier, M. [BAM, Germany

2012-06-28T23:59:59.000Z

210

Physical and chemical properties of the regional mixed layer of Mexico's Megapolis Part II: Evaluation of measured and modeled trace gases and particle size distributions  

SciTech Connect (OSTI)

This study extends the work of Baumgardner et al. (2009) in which measurements of trace gases and particles at a remote, high-altitude mountain site 60 km from Mexico City were analyzed with respect to the origin of air masses. In the current evaluation, the temperature, water vapor, ozone (O3), carbon monoxide (CO), acyl peroxy nitrate (APN) and particle size distributions (PSDs) of the mass concentrations of sulfate, nitrate, ammonium and organic mass (OM) were simulated with the WRF-Chem chemical transport model and compared with the measurements at the mountain site. The model prediction of the diurnal trends of the gases were well correlated with the measurements before the regional boundary layer reached the measurement site but underestimated the concentrations after that time. The differences are caused by an overly rapid growth of the boundary layer by the model with too much dilution. There also appears to be more O3 produced by photochemical production, downwind of the emission sources, than predicted by the model. The measured and modeled PSDs compare very well with respect to their general shape and diameter of the peak concentrations. The spectra are log normally distributed with most of the mass in the accumulation mode and the geometric diameter centered at 200 20 nm, with little observed or predicted change with respect to the origin of the air mass or the time when the RBL is above the Altzomoni research. Only the total mass changed with time and air mass origin. The invariability of the average diameter of the accumulation mode suggests that there is very little growth of the particles by condensation or coagulation after six hours of aging downwind of the major sources of anthropogenic emissions in Mexicos Megapolis.

Ochoa, Carlos; Baumgardner, Darrel; Grutter, M.; Allan, James D.; Fast, Jerome D.; Rappengluck, B.

2012-10-31T23:59:59.000Z

211

Considerations When Using Grain Contracts  

E-Print Network [OSTI]

Grain contracts can help farmers manage the increasing risks of production and the price volatility of the market. This publication explains grain contracts and how to use them wisely as a risk management tool....

Wisner, Robert; McCorkle, Dean

2000-04-07T23:59:59.000Z

212

Grain Destruction in Interstellar Shocks  

E-Print Network [OSTI]

Interstellar shock waves can erode and destroy grains present in the shocked gas, primarily as the result of sputtering and grain-grain collisions. Uncertainties in current estimates of sputtering yields are reviewed. Results are presented for the simple case of sputtering of fast grains being stopped in cold gas. An upper limit is derived for sputtering of refractory grains in C-type MHD shocks: shock speeds $v_s \\gtrsim 50 \\kms$ are required for return of more than 30\\% of the silicate to the gas phase. Sputtering can also be important for removing molecular ice mantles from grains in two-fluid MHD shock waves in molecular gas. Recent estimates of refractory grain lifetimes against destruction in shock waves are summarized, and the implications of these short lifetimes are discussed.

B. T. Draine

1995-08-16T23:59:59.000Z

213

Process for producing large grain cadmium telluride  

DOE Patents [OSTI]

A process is described for producing a cadmium telluride polycrystalline film having grain sizes greater than about 20 {micro}m. The process comprises providing a substrate upon which cadmium telluride can be deposited and placing that substrate within a vacuum chamber containing a cadmium telluride effusion cell. A polycrystalline film is then deposited on the substrate through the steps of evacuating the vacuum chamber to a pressure of at least 10{sup {minus}6} torr.; heating the effusion cell to a temperature whereat the cell releases stoichiometric amounts of cadmium telluride usable as a molecular beam source for growth of grains on the substrate; heating the substrate to a temperature whereat a stoichiometric film of cadmium telluride can be deposited; and releasing cadmium telluride from the effusion cell for deposition as a film on the substrate. The substrate then is placed in a furnace having an inert gas atmosphere and heated for a sufficient period of time at an annealing temperature whereat cadmium telluride grains on the substrate grow to sizes greater than about 20 {micro}m.

Hasoon, F.S.; Nelson, A.J.

1996-01-16T23:59:59.000Z

214

Effect of acicular ferrite formation on grain refinement in the coarse-grained region of heat-affected zone  

SciTech Connect (OSTI)

The microstructure of acicular ferrite and its formation for the grain refinement of coarse-grained region of heat-affected zone of high strength low-alloy bainite steels were studied using three-dimensional reconstruction technique. Crystallographic grain size was analyzed by means of electron backscatter diffraction. It was revealed that the microstructure in the coarse-grained region of the heat-affected zone consisted of predominantly bainite packets and a small proportion of acicular ferrite. Acicular ferrite was of lath or plate-like rather than needle or rod-like morphology. Tempering of the coarse-grained region of heat-affected zone showed that the acicular ferrite was more stable than the bainite, indicating that the acicular ferrite was formed prior to bainite. The acicular ferrite laths or plates divided the prior austenite grains into smaller and separate regions, and confining the bainite transformed at lower temperatures in the smaller regions and hence leading to the grain refinement in the coarse-grained region of the heat-affected zone.

Wan, X.L.; Wei, R. [Institute of Advanced Steels and Welding Technology, Hubei Provincial Key Laboratory for Systems Science on Metallurgical Processing, Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China); Wu, K.M., E-mail: wukaiming@wust.edu.cn [Institute of Advanced Steels and Welding Technology, Hubei Provincial Key Laboratory for Systems Science on Metallurgical Processing, Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China)

2010-07-15T23:59:59.000Z

215

High spring temperatures decrease peach fruit size  

E-Print Network [OSTI]

useful in dif?cult fruit- and crop level interactions inin light of the increasing fruit size distribution and waterpressure for large-size fruits. CALIFORNIA AGRICULTURE

Lopez, Geraldo; Johnson, R. Scott; DeJong, Theodore M.

2007-01-01T23:59:59.000Z

216

Grain constraint and size effects in shape memory alloy microwires  

E-Print Network [OSTI]

Shape memory alloys exhibit interesting and useful properties, such as the shape memory effect and superelasticity. Among the many alloy families that have been shown to exhibit shape memory properties the ones based on ...

Ueland, Stian Melhus

2013-01-01T23:59:59.000Z

217

austenite grain size: Topics by E-print Network  

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

105 mathrmcm-3)-14 (where tmathrmff is the free-fall time at hydrogen number density nmathrmH in the core, and S the enhancement factor to the...

218

alloy grain size: Topics by E-print Network  

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

105 mathrmcm-3)-14 (where tmathrmff is the free-fall time at hydrogen number density nmathrmH in the core, and S the enhancement factor to the...

219

Technical Letter Report Development of Flaw Size Distribution Tables Including Effects of Flaw Depth Sizing Errors for Draft 10CFR 50.61a (Alternate PTS Rule) JCN-N6398, Task 4  

SciTech Connect (OSTI)

This document describes a new method to determine whether the flaws in a particular reactor pressure vessel are consistent with the assumptions regarding the number and sizes of flaws used in the analyses that formed the technical justification basis for the new voluntary alternative Pressurized Thermal Shock (PTS) rule (Draft 10 CFR 50.61a). The new methodology addresses concerns regarding prior methodology because ASME Code Section XI examinations do not detect all fabrication flaws, they have higher detection performance for some flaw types, and there are flaw sizing errors always present (e.g., significant oversizing of small flaws and systematic under sizing of larger flaws). The new methodology allows direct comparison of ASME Code Section XI examination results with values in the PTS draft rule Tables 2 and 3 in order to determine if the number and sizes of flaws detected by an ASME Code Section XI examination are consistent with those assumed in the probabilistic fracture mechanics calculations performed in support of the development of 10 CFR 50.61a.

Simonen, Fredric A.; Gosselin, Stephen R.; Doctor, Steven R.

2013-04-22T23:59:59.000Z

220

NanoSIMS analysis of arsenic and selenium in cereal grain  

SciTech Connect (OSTI)

Cereals are an important source of selenium (Se) to humans and many people have inadequate intakes of this essential trace element. Conversely, arsenic (As) is toxic and may accumulate in rice grain at levels that pose a health risk. Knowledge of the localization of selenium and arsenic within the cereal grain will aid understanding of their deposition patterns and the impact of processes such as milling. High-resolution secondary ion mass spectrometry (NanoSIMS) was used to determine the localization of Se in wheat (Triticum aestivum) and As in rice (Oryza sativa). Combined synchrotron X-ray fluorescence (S-XRF) and NanoSIMS analysis utilized the strengths of both techniques. Selenium was concentrated in the protein surrounding the starch granules in the starchy endosperm cells and more homogeneously distributed in the aleurone cells but with Se-rich hotspots. Arsenic was concentrated in the subaleurone endosperm cells in association with the protein matrix rather than in the aleurone cells. NanoSIMS indicated that the high intensity of As identified in the S-XRF image was localized in micron-sized hotspots near the ovular vascular trace and nucellar projection. This is the first study showing subcellular localization in grain samples containing parts per million concentrations of Se and As. There is good quantitative agreement between NanoSIMS and S-XRF.

Moore, Katie L.; Schrder, Markus; Lombi, Enzo; Zhao, Fang-Jie; McGrath, Steve P.; Hawkesford, Malcolm J.; Shewry, Peter R.; Grovenor, Chris R.M. (Rothamsted); (UCopenhagen); (Oxford)

2012-09-05T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

Modeling of stresses at grain boundaries with respect to occurrence of stress corrosion cracking  

SciTech Connect (OSTI)

The distributions of elastic stresses/strains in the grain boundary regions were studied by the analytical and the finite element models. The grain boundaries represent the sites where stress concentration occurs as a result of discontinuity of elastic properties across the grain boundary and the presence of second phase particles elastically different from the surrounding matrix grains. A quantitative analysis of those stresses for steels and nickel based alloys showed that the stress concentrations in the grain boundary regions are high enough to cause a local microplastic deformation even when the material is in the macroscopic elastic regime. The stress redistribution as a result of such a plastic deformation was discussed.

Kozaczek, K.J. [Oak Ridge National Lab., TN (United States); Sinharoy, A.; Ruud, C.O. [Pennsylvania State Univ., University Park, PA (United States); McIlree, A.R. [Electric Power Research Institute, Palo Alto, CA (United States)

1995-12-31T23:59:59.000Z

222

Alignment of suprathermally rotating grains  

E-Print Network [OSTI]

It is shown, that mechanical alignment can be efficient for suprathermally rotating grains, provided that they drift with supersonic velocities. Such a drift should be widely spread due to both Alfv\\'{e}nic waves and ambipolar diffusion. Moreover, if suprathermal rotation is caused by grain interaction with a radiative flux, it is shown, that mechanical alignment may be present even in the absence of supersonic drift. This means that the range of applicability of mechanical alignment is wider that it is generally accepted and it can rival the paramagnetic one. We also study the latter mechanism and reexamine the interplay between poisoning of active sites and desorption of molecules blocking the access to the active sites of H$_{2}$ formation in order to explain the observed poor alignment of small grains and good alignment of large grains. To have a more comprehensive picture of alignment we briefly discuss the alignment by radiation fluxes and caused by grain magnetic moments.

A. Lazarian

1995-08-15T23:59:59.000Z

223

Determination of lateral size distribution of type-II ZnTe/ZnSe stacked submonolayer quantum dots via spectral analysis of optical signature of the Aharanov-Bohm excitons  

SciTech Connect (OSTI)

For submonolayer quantum dot (QD) based photonic devices, size and density of QDs are critical parameters, the probing of which requires indirect methods. We report the determination of lateral size distribution of type-II ZnTe/ZnSe stacked submonolayer QDs, based on spectral analysis of the optical signature of Aharanov-Bohm (AB) excitons, complemented by photoluminescence studies, secondary-ion mass spectroscopy, and numerical calculations. Numerical calculations are employed to determine the AB transition magnetic field as a function of the type-II QD radius. The study of four samples grown with different tellurium fluxes shows that the lateral size of QDs increases by just 50%, even though tellurium concentration increases 25-fold. Detailed spectral analysis of the emission of the AB exciton shows that the QD radii take on only certain values due to vertical correlation and the stacked nature of the QDs.

Ji, Haojie; Dhomkar, Siddharth; Roy, Bidisha; Kuskovsky, Igor L. [Department of Physics, Queens College of CUNY, Queens, New York 11367 (United States); The Graduate Center of CUNY, New York, New York 10016 (United States); Shuvayev, Vladimir [Department of Physics, Queens College of CUNY, Queens, New York 11367 (United States); Deligiannakis, Vasilios; Tamargo, Maria C. [The Graduate Center of CUNY, New York, New York 10016 (United States); Department of Chemistry, City College of CUNY, New York, New York 10031 (United States); Ludwig, Jonathan [National High Magnetic Field Laboratory, Tallahassee, Florida 32310 (United States); Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States); Smirnov, Dmitry [National High Magnetic Field Laboratory, Tallahassee, Florida 32310 (United States); Wang, Alice [Evans Analytical Group, Sunnyvale, California 94086 (United States)

2014-10-28T23:59:59.000Z

224

Drying and Storing Sorghum Grain.  

E-Print Network [OSTI]

old sarking. Clean up any nea~l)! >ourc.es of insert infestatiou such as feed rooms. mil- c.llinerj. spilletl grain ar~tl rat harbors. Apply a reii. Apply the fumigant when there is no wind and when the temperature of the headspace above the grain... cause high prevent the possibility of windstorm damage wher~ insect infestation and heating which result in con- siderable spoilage of grain. the hins are empty. 2 Figure 3. An example of how "trash" accumulates in pockets as the bins are filled...

Hutchison, J. E.

1959-01-01T23:59:59.000Z

225

A finite element model of grain boundary sliding for nanostructured metals  

E-Print Network [OSTI]

Nanocrystalline metals, i.e., polycrystalline metals with grain sizes in the nanometer range, have elicited significant interest recently due to their potential for achieving higher material strength in combination with ...

Jrusalem, Antoine, 1979-

2004-01-01T23:59:59.000Z

226

On the AU Mic debris disk: density profiles, grain properties and dust dynamics  

E-Print Network [OSTI]

We present the first comprehensive analysis of the AU Mic debris disk properties since the system was discovered by Kalas et al. (2004), and we explore whether the dynamical model, successful to reproduce the Beta Pic brightness profile could apply to AU Mic. We calculate the surface density profile of the AU Mic disk by performing the inversion of the near-IR and visible scattered light brightness profiles measured by Liu (2004a) and Krist et al. (2005), respectively. We discuss the grain properties by analysing the blue color of the disk in the visible (Krist et al. 2005) and by fitting the disk spectral energy distribution. We show that irrespective of the mean scattering asymmetry factor of the grains, most of the emission arises from an asymmetric, collisionally-dominated region that peaks close to the surface brightness break around 35 AU. The elementary scatterers at visible wavelengths are found to be sub-micronic, but the inferred size distribution underestimates the amount of large grains, resulting in too low sub-millimeter emissions compared to the observations. From our inversion procedure, we find that the V- to H-band scattering cross sections ratio increases outside 40 AU, in line with the observed color gradient of the disk. We show that a standard, solar-like stellar wind generates a pressure force onto the dust particles that behaves much like a radiation pressure force. With an assumed Mdot ~ 300 Mdot_sun, the wind pressure overcomes the radiation pressure and this effect is enhanced by the stellar flares. This explains the similarity between the Beta Pic and AU Mic brightness profiles. In both cases, the color gradient beyond 120 AU for Beta Pic and 35 AU for AU Mic, is believed to be a direct consequence of the dust dynamics.

J. C. Augereau; H. Beust

2006-04-13T23:59:59.000Z

227

Dense, finely, grained composite materials  

DOE Patents [OSTI]

Dense, finely grained composite materials comprising one or more ceramic phase or phase and one or more metallic and/or intermetallic phase or phases are produced by combustion synthesis. Spherical ceramic grains are homogeneously dispersed within the matrix. Methods are provided, which include the step of applying mechanical pressure during or immediately after ignition, by which the microstructures in the resulting composites can be controllably selected.

Dunmead, Stephen D. (Davis, CA); Holt, Joseph B. (San Jose, CA); Kingman, Donald D. (Danville, CA); Munir, Zuhair A. (Davis, CA)

1990-01-01T23:59:59.000Z

228

RESEARCH ARTICLE The contribution of China's Grain to Green Program  

E-Print Network [OSTI]

RESEARCH ARTICLE The contribution of China's Grain to Green Program to carbon sequestration Dan Liu, the magnitude and distribution of carbon sequestration induced by GGP remain unknown. In this study, we in southern China. The economic benefits of carbon sequestration from the GGP were also estimated according

Xiao, Jingfeng

229

Infrared Emission from Interstellar Dust. I. Stochastic Heating of Small Grains  

E-Print Network [OSTI]

We present a method for calculating the infrared emission from a population of dust grains heated by starlight, including very small grains for which stochastic heating by starlight photons results in high temperature transients. Because state-to-state transition rates are generally unavailable for complex molecules, we consider model PAH, graphitic, and silicate grains with realistic vibrational mode spectra and realistic radiative properties. The vibrational density of states is used in a statistical-mechanical description of the emission process. Unlike previous treatments, our approach fully incorporates multiphoton heating effects, important for large grains or strong radiation fields. We discuss how the "temperature" of the grain is related to its vibrational energy. By comparing with an "exact" statistical calculation of the emission process, we determine the conditions under which the "thermal" and the "continuous cooling" approximations can be used to calculate the emission spectrum. We present results for the infrared emission spectra of PAH grains of various sizes heated by starlight. We show how the relative strengths of the 6.2, 7.7, and 11.3um features depend on grain size, starlight spectrum and intensity, and grain charging conditions. We show results for grains in the "cold neutral medium", "warm ionized medium", and representative conditions in photodissociation regions. Our model results are compared to observed ratios of emission features for reflection nebulae and photodissociation regions, the Milky Way, normal spiral galaxies, and starburst galaxies.

B. T. Draine; Aigen Li

2000-11-16T23:59:59.000Z

230

6, 1184511875, 2006 A new SIze REsolved  

E-Print Network [OSTI]

the aerosol size distribution into sections and solves the GDE by splitting coagulation and condensation Interactive Discussion EGU that affect the aerosol size/composition distribution are therefore crucial. ThreeACPD 6, 11845­11875, 2006 A new SIze REsolved Aerosol Model E. Debry et al. Title Page Abstract

Boyer, Edmond

231

Investigation of thermochemical biorefinery sizing and environmental sustainability impacts for conventional supply system and distributed pre-processing supply system designs  

SciTech Connect (OSTI)

The 2011 US Billion-Ton Update estimates that by 2030 there will be enough agricultural and forest resources to sustainably provide at least one billion dry tons of biomass annually, enough to displace approximately 30% of the country's current petroleum consumption. A portion of these resources are inaccessible at current cost targets with conventional feedstock supply systems because of their remoteness or low yields. Reliable analyses and projections of US biofuels production depend on assumptions about the supply system and biorefinery capacity, which, in turn, depend upon economic value, feedstock logistics, and sustainability. A cross-functional team has examined combinations of advances in feedstock supply systems and biorefinery capacities with rigorous design information, improved crop yield and agronomic practices, and improved estimates of sustainable biomass availability. A previous report on biochemical refinery capacity noted that under advanced feedstock logistic supply systems that include depots and pre-processing operations there are cost advantages that support larger biorefineries up to 10 000 DMT/day facilities compared to the smaller 2000 DMT/day facilities. This report focuses on analyzing conventional versus advanced depot biomass supply systems for a thermochemical conversion and refinery sizing based on woody biomass. The results of this analysis demonstrate that the economies of scale enabled by advanced logistics offsets much of the added logistics costs from additional depot processing and transportation, resulting in a small overall increase to the minimum ethanol selling price compared to the conventional logistic supply system. While the overall costs do increase slightly for the advanced logistic supply systems, the ability to mitigate moisture and ash in the system will improve the storage and conversion processes. In addition, being able to draw on feedstocks from further distances will decrease the risk of biomass supply to the conversion facility.

David J. Muth, Jr.; Matthew H. Langholtz; Eric C. D. Tan; Jacob J. Jacobson; Amy Schwab; May M. Wu; Andrew Argo; Craig C. Brandt; Kara G. Cafferty; Yi-Wen Chiu; Abhijit Dutta; Laurence M. Eaton; Erin M. Searcy

2014-08-01T23:59:59.000Z

232

Wave propagation, stress relaxation, and grain-to-grain shearing in saturated, unconsolidated marine sediments  

E-Print Network [OSTI]

Wave propagation, stress relaxation, and grain-to-grain shearing in saturated, unconsolidated in saturated, unconsolidated granular materials, including marine sediments, is developed in this article

Buckingham, Michael

233

Effective grain surface area in the formation of molecular hydrogen in interstellar clouds  

E-Print Network [OSTI]

In the interstellar clouds, molecular hydrogens are formed from atomic hydrogen on grain surfaces. An atomic hydrogen hops around till it finds another one with which it combines. This necessarily implies that the average recombination time, or equivalently, the effective grain surface area depends on the relative numbers of atomic hydrogen influx rate and the number of sites on the grain. Our aim is to discover this dependency. We perform a numerical simulation to study the recombination of hydrogen on grain surfaces in a variety of cloud conditions. We use a square lattice (with a periodic boundary condition) of various sizes on two types of grains, namely, amorphous carbon and olivine. We find that the steady state results of our simulation match very well with those obtained from a simpler analytical consideration provided the `effective' grain surface area is written as $\\sim S^{\\alpha}$, where, $S$ is the actual physical grain area and $\\alpha$ is a function of the flux of atomic hydrogen which is determined from our simulation. We carry out the simulation for various astrophysically relevant accretion rates. For high accretion rates, small grains tend to become partly saturated with $H$ and $H_2$ and the subsequent accretion will be partly inhibited. For very low accretion rates, the number of sites to be swept before a molecular hydrogen can form is too large compared to the actual number of sites on the grain, implying that $\\alpha$ is greater than unity.

Sandip Kumar Chakrabarti; Ankan Das; Kinsuk Acharyya; Sonali Chakrabarti

2008-06-28T23:59:59.000Z

234

Optical method for the determination of grain orientation in films  

DOE Patents [OSTI]

A method for the determination of grain orientation in a film sample is provided comprising the steps of measuring a first transient optical response of the film and determining the contribution to the transient optical response arising from a change in the energy distribution of the electrons in the sample, determining the contribution to the transient optical response arising from a propagating strain pulse within the sample, and determining the contribution to the transient optical response arising from a change in sample temperature of the sample. The grain orientation of the sample may be determined using the contributions to the transient optical response arising from the change in the energy distribution of the electrons, the propagating strain pulse, and the change in sample temperature. Additionally, a method for determination of the thickness of a film sample is provided. The grain orientation of the sample is first determined. The grain orientation, together with the velocity of sound and a propagation time of a strain pulse through the sample are then used to determine the thickness of the film sample.

Maris, Humphrey J. (Barrington, RI)

2001-01-01T23:59:59.000Z

235

Grain and Grain-Boundary Critical Currents in Coated Conductors with Non-Correlating YBa2Cu3O7 and Substrate Grain-Boundary Networks  

SciTech Connect (OSTI)

The superconducting grain-boundary (GB) network of coated conductors (CCs) is usually assumed to be a replica of the substrate network. In this letter, we analyze IBAD and RABITS CCs, where such replica either do or do not exist. We have analyzed the effect of GB overgrowth on the critical currents by quantifying the average superconducting grain size and determining the intragrain and grain-boundary critical current densities, J{sub c}{sup G} and J{sub c}{sup GB}. We have employed a recently developed inductive methodology enabling the simultaneous determination of these three parameters. We show that the percolative J{sub c}{sup GB} may be reduced by 50% if the GB networks do not correlate, while J{sub c}{sup G} and the grain pinning properties appear unaffected.

Palau, A. [ICMAB, Barcelona, Spain; Puig, T. [ICMAB, Barcelona, Spain; Obradors, X. [ICMAB, Barcelona, Spain; Feenstra, Roeland [ORNL; Gapud, Albert Agcaoili [ORNL; Specht, Eliot D [ORNL; Feldmann, D. M. [University of Wisconsin, Madison; Holesinger, T. G. [Los Alamos National Laboratory (LANL)

2006-01-01T23:59:59.000Z

236

Petrographic characterization of Kentucky coals. Final report. Part V. Pyrite size/form/microlithotype distribution in western Kentucky prepared coals and in channel samples from western Kentucky and western Pennsylvania  

SciTech Connect (OSTI)

Pyrite and marcasite distribution has been characterized in several western Kentucky coals, western Pennsylvania coals, and coals from western Kentucky preparation plants using three parameters of size, morphology, and microlithotype association. A classification system was developed to provide a consistent method for recording different pyrite/marcasite types. Sulfides were microscopically measured and placed in one of six size divisions (<5, 5 to 10, 10 to 40, 40 to 75, 75 to 100, or >150..mu..m) rather than absolute size. Five categories (euhedral, framboidal, dendritic, massive, or cleat) describe pyrite/marcasite morphology. The third parameter identifies the microlithotype (vitrite, clarite, inertite, liptite, durite, vitrinertite, trimacerite, or carbominerite) in which the pyrite occurs (not including the measured sulfide). Carbominerite is a mineral/organic association dominated by mineral matter. The percentage of each variable represents the total number of counts per sample and not the volume of pyrite. Throughout the studies, both sulfides are collectively referred to as pyrite unless otherwise specified. This paper describes the different studies which were undertaken to test the usefulness of this pyrite classification system. Systematic trends in pyrite variability were determined for the Springfield coal and Herrin of western Kentucky. Pyrite characterization of the Lower Kittanning coal from western Pennsylvania shows that certain pyrite morphologies can be an expression of the environments deposition of coal bodies. Studies of western Kentucky prepared coals demonstrate that pyrite characterization apparently can provide a method for predicting pyrite behavior and the extent of pyrite removal for specific coals. 77 references, 15 figures, 19 tables.

Frankle, K.A.; Hower, J.C.

1983-01-01T23:59:59.000Z

237

Current transport along grain boundaries in d-wave superconductors.  

SciTech Connect (OSTI)

The use of a classic phase retrieval algorithm has been previously used to determine the local critical current J{sub c}(x) along the length of grain boundary Josephson junctions that can be characterized using a standard s-wave model. The phase retrieval approach has been modified for use with d-wave dominated superconductors to allow for negative local currents along the boundary. In general solutions to the 1-D phase problem are not unique, however in the present work special constraints are employed experimentally to ensure uniqueness. The various current distribution solutions and their possible uniqueness are explored. The solutions are consistent with most existing d-wave Josephson junction boundary models and can be used to understand the basic current distribution along 45 degree YaBa{sub 2}Cu{sub 3}O{sub 7-x} grain boundary junctions as well as providing a means for mapping the location of self-generated flux cores.

Carmody, M.; Marks, L. D.; Merkle, K. L.; Materials Science Division; Northwestern Univ.

2002-05-01T23:59:59.000Z

238

Port of Houston Intermodal Grain Transfer System and Market Area, 1976 - 1977.  

E-Print Network [OSTI]

to 41 feet. This implies that these vessels grain at the Port of Houston. Practical experience has were not able to be fully loaded. Bulk carriers and tank- shown that up to a point, the larger the ship employed in the transport of bulk cargoes... AND SHIPMENT PATTERNS ............... 12 MODES OF TRANSPORTATION ON GRAIN AND SOYBEAN RECEIPTS ..................................... 14 FOREIGN DESTl NATIONS ..................................... 14 CARGO SIZES BY DESTINATION AND COMMODITY .......... 14...

Fuller, Stephen W.; Paggi, Mechel S.

1978-01-01T23:59:59.000Z

239

The rule of the stock distribution with large bell in blast furnace  

SciTech Connect (OSTI)

This paper describes in detail, starting from the basic equation of materials falling from a two bell furnace top system, how a number of mathematical expressions which govern the stock distribution of the throat were derived. An analysis was then made by applying these equations on topics, such as stockline levels, charging sequences, stock grain size, large bell angle and batch weight. This demonstrates that a reasonable two bells top charging system and practice could be established theoretically. Furthermore, character numbers for stock distribution, such as E{sub B} and D{sub K}, were developed for a possible computer application.

Liu Yuncai [Shoudu Iron and Steel Co., Beijing (China)

1996-12-31T23:59:59.000Z

240

Effective porosity and pore-throat sizes of Conasauga Group mudrock: Application, test and evaluation of petrophysical techniques  

SciTech Connect (OSTI)

Effective porosity (specifically referring to the interconnected pore space) was recently recognized as being essential in determining the effectiveness and extent of matrix diffusion as a transport mechanism within fractured low-permeability rock formations. The research presented in this report was performed to test the applicability of several petrophysical techniques for the determination of effective porosity of fine-grained siliciclastic rocks. In addition, the aim was to gather quantitative data on the effective porosity of Conasauga Group mudrock from the Oak Ridge Reservation (ORR). The quantitative data reported here include not only effective porosities based on diverse measurement techniques, but also data on the sizes of pore throats and their distribution, and specimen bulk and grain densities. The petrophysical techniques employed include the immersion-saturation method, mercury and helium porosimetry, and the radial diffusion-cell method.

Dorsch, J. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; Katsube, T.J. [Geological Survey of Canada, Ottawa, Ontario (Canada). Mineral Resources Div.; Sanford, W.E. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Civil and Environmental Engineering; Dugan, B.E. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Civil and Mineral Engineering; Tourkow, L.M. [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth and Atmospheric Sciences

1996-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

Effect of lift force on the aerodynamics of dust grains in the protoplanetary disk  

E-Print Network [OSTI]

We newly introduce lift force into the aerodynamics of dust grains in the protoplanetary disk. Although many authors have so far investigated the effects of the drag force, gravitational force and electric force on the dust grains, the lift force has never been considered as a force exerted on the dust grains in the gas disk. If the grains are spinning and moving in the fluid, then the lift force is exerted on them. We show in this paper that the dust grains can be continuously spinning due to the frequent collisions so that the lift force continues to be exerted on them, which is valid in a certain parameter space where the grain size is larger than ~ 1 m and where the distance from the central star is larger than 1 AU for the minimum mass solar nebula. In addition, we estimate the effects of the force on the grain motion and obtain the result that the mean relative velocity between the grains due to the lift force is comparable to the gas velocity in the Kepler rotational frame when the Stokes number and li...

Yamaguchi, Masaki S

2014-01-01T23:59:59.000Z

242

Particle Size Distribution of Gypseous Samples  

E-Print Network [OSTI]

to conditions in the field. In order to understand the true characterization of the soil and the gypsum particles, the entire soil sample should be analyzed. Four different approaches to the BaCl2 method presented in the literature (Hesse, 1976, Matar...

Arnett, Morgan P.

2010-01-16T23:59:59.000Z

243

Cluster size distribution for free molecular agglomeration  

SciTech Connect (OSTI)

Dobbins and Megaridis have observed soot agglomerates in a diffusion flame via thermophoretic sampling. The agglomerates are made up of spherules with a typical diameter of about 30 nm. A characteristic of the agglomerate is the relatively low density of the structure with much open space. This study is concerned with modeling the agglomeration growth process.

Mulholland, G.W.; Samson, R.J.; Mountain, R.D.; Ernst, M.H.

1988-01-01T23:59:59.000Z

244

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 (OSTI)

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 licensees 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

245

[Grain boundary and interface kinetics during ion irradiation  

SciTech Connect (OSTI)

Proposed here is renewed support of a research program focused on interface motion and phase transformation during ion irradiation, with emphasis on elemental semiconductors. Broadly speaking, the aims of this program are to explore defect kinetics in amorphous and crystalline semiconductors, and to relate defect dynamics to interface motion and phase transformations. Over the last three years, we initiated a program under DOE support to explore crystallization and amorphization of elemental semiconductors under irradiation. This research has enabled new insights about the nature of defects in amorphous semiconductors and about microstructural evolution in the early stages of crystallization. In addition, we have demonstrated almost arbitrary control over the relative rates of crystal nucleation and crystal growth in silicon. As a result, the impinged grain microstructure of thin (100 nm) polycrystalline films crystallized under irradiation can be controlled with grain sizes ranging from a few nanometers to several micrometers, which may have interesting technological implications.

Atwater, H.A.

1991-12-31T23:59:59.000Z

246

(Grain boundary and interface kinetics during ion irradiation)  

SciTech Connect (OSTI)

Proposed here is renewed support of a research program focused on interface motion and phase transformation during ion irradiation, with emphasis on elemental semiconductors. Broadly speaking, the aims of this program are to explore defect kinetics in amorphous and crystalline semiconductors, and to relate defect dynamics to interface motion and phase transformations. Over the last three years, we initiated a program under DOE support to explore crystallization and amorphization of elemental semiconductors under irradiation. This research has enabled new insights about the nature of defects in amorphous semiconductors and about microstructural evolution in the early stages of crystallization. In addition, we have demonstrated almost arbitrary control over the relative rates of crystal nucleation and crystal growth in silicon. As a result, the impinged grain microstructure of thin (100 nm) polycrystalline films crystallized under irradiation can be controlled with grain sizes ranging from a few nanometers to several micrometers, which may have interesting technological implications.

Atwater, H.A.

1991-01-01T23:59:59.000Z

247

Images of Vega Dust Ring at 350 and 450 microns: New Clues to the Trapping of Multiple-Sized Dust Particles in Planetary Resonances  

E-Print Network [OSTI]

We have used the SHARC II camera at Caltech Submillimeter Observatory to make 350 and 450 micron images of the Vega dust disk at spatial resolutions (FWHM) of 9.7" and 11.1", respectively. The images show a ring-like morphology (radius \\~ 100 AU) with inhomogeneous structure that is qualitatively different from that previously reported at 850 microns and longer wavelengths. We attribute the 350/450 micron emission to a grain population whose characteristic size (~ 1 mm) is intermediate between that of the cm-sized grains responsible for emission longward of 850 microns and the much smaller grains (< 18 microns) in the extensive halo, visible at 70 microns, discussed by Su et al. (2005). We have combined our submillimeter images with Spitzer data at 70 microns to produce 2-d maps of line-of-sight optical depth (relative column density). These "tau maps" suggest that the mm-sized grains are located preferentially in three symmetrically-located concentrations. If so, then this structure could be understood in terms of the Wyatt (2003) model in which planetesimals are trapped in the mean motion resonances of a Neptune-mass planet at 65 AU, provided allowance is made for the spatial distribution of dust grains to differ from that of the parent planetesimals. The peaks of the tau maps are, in fact, located near the expected positions corresponding to the 4:3 resonance. If this identification is confirmed by future observations, it would resolve an ambiguity with regard to the location of the planet.

K. A. Marsh; C. D. Dowell; T. Velusamy; K. Grogan; C. A. Beichman

2006-06-14T23:59:59.000Z

248

Spacing of Rows in Corn and Its Effect Upon Grain Yield.  

E-Print Network [OSTI]

, was added as a third distribution. The results for the five-year period are shown in the follnn.ing table. S,PACING ROWS IN CORN AND EFFECT UPON GRAIN YIELD 9 hould be pointed out that the low ~ield from the six-foot spacing I2 mss, undouhteclly, due... comparable. It is noticeable that the grain yield each pear is consistently in favor of the three-foot spacing, as is also the average for the whole period of five years. These results indicate that the actual yield in grain secure:l from the three-foot...

Conner, A. B. (Arthur Benjamin)

1918-01-01T23:59:59.000Z

249

Cast Stainless Steel Ferrite and Grain Structure  

SciTech Connect (OSTI)

In-service inspection requirements dictate that piping welds in the primary pressure boundary of light-water reactors be subject to a volumetric examination based on the rules contained within the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI. The purpose of the inspection is the reliable detection and accurate sizing of service-induced degradation and/or material flaws introduced during fabrication. The volumetric inspection is usually carried out using ultrasonic testing (UT) methods. However, the varied metallurgical macrostructures and microstructures of cast austenitic stainless steel piping and fittings, including statically cast stainless steel and centrifugally cast stainless steel (CCSS), introduce significant variations in the propagation and attenuation of ultrasonic energy. These variations complicate interpretation of the UT responses and may compromise the reliability of UT inspection. A review of the literature indicated that a correlation may exist between the microstructure and the delta ferrite content of the casting alloy. This paper discusses the results of a recent study where the goal was to determine if a correlation existed between measured and/or calculated ferrite content and grain structure in CCSS pipe.

Ruud, Clayton O.; Ramuhalli, Pradeep; Meyer, Ryan M.; Mathews, Royce; Diaz, Aaron A.; Anderson, Michael T.

2012-09-01T23:59:59.000Z

250

Atom probe study of grain boundary segregation in technically pure molybdenum  

SciTech Connect (OSTI)

Molybdenum, a metal with excellent physical, chemical and high-temperature properties, is an interesting material for applications in lighting-technology, high performance electronics, high temperature furnace construction and coating technology. However, its applicability as a structural material is limited because of the poor oxidation resistance at high temperatures and a brittle-to-ductile transition around room temperature, which is influenced by the grain size and the content of interstitial impurities at the grain boundaries. Due to the progress of the powder metallurgical production during the last decades, the amount of impurities in the current quality of molybdenum has become so small that surface sensitive techniques are not applicable anymore. Therefore, the atom probe, which allows the detection of small amounts of impurities as well as their location, seems to be a more suitable technique. However, a site-specific specimen preparation procedure for grain boundaries in refractory metals with a dual focused ion beam/scanning electron microscope is still required. The present investigation describes the development and successful application of such a site-specific preparation technique for grain boundaries in molybdenum, which is significantly improved by a combination with transmission electron microscopy. This complimentary technique helps to improve the visibility of grain boundaries during the last preparation steps and to evidence the presence of grain and subgrain boundaries without segregants in atom probe specimens. Furthermore, in industrially processed and recrystallized molybdenum sheets grain boundary segregation of oxygen, nitrogen and potassium is successfully detected close to segregated regions which are believed to be former sinter pores. - Highlights: First study of grain boundary segregation in molybdenum by atom probe Site-specific preparation technique by FIB and TEM successfully developed Grain boundary segregation of oxygen, nitrogen and potassium found Segregation in former sinter-pores detected Presence of grain boundaries without segregation evidenced.

Babinsky, K., E-mail: katharina.babinsky@stud.unileoben.ac.at [Montanuniversitt Leoben, Department of Physical Metallurgy and Materials Testing, Franz-Josef Strae 18, 8700 Leoben (Austria); Weidow, J., E-mail: jonathan.weidow@chalmers.se [Chalmers University of Technology, Department of Applied Physics, 412 96 Gothenburg (Sweden); Knabl, W., E-mail: wolfram.knabl@plansee.com [PLANSEE SE, Metallwerk-Plansee-Strae 71, 6600 Reutte (Austria); Lorich, A., E-mail: alexander.lorich@plansee.com [PLANSEE SE, Metallwerk-Plansee-Strae 71, 6600 Reutte (Austria); Leitner, H., E-mail: harald.leitner@bohler-edelstahl.at [Montanuniversitt Leoben, Department of Physical Metallurgy and Materials Testing, Franz-Josef Strae 18, 8700 Leoben (Austria); Primig, S., E-mail: sophie.primig@unileoben.ac.at [Montanuniversitt Leoben, Department of Physical Metallurgy and Materials Testing, Franz-Josef Strae 18, 8700 Leoben (Austria)

2014-01-15T23:59:59.000Z

251

Particle in cell calculation of plasma force on a small grain in a non-uniform collisional sheath  

E-Print Network [OSTI]

The plasma force on grains of specified charge and height in a collisional DC plasma sheath is calculated using the multidimensional particle in cell code COPTIC. The background ion velocity distribution functions for the ...

Hutchinson, Ian H.

252

A simulation-based soil and water resource evaluation for ratoon cropping grain sorghum in the central blacklands of Texas  

E-Print Network [OSTI]

ure 1. Grain yield cumulative probability distributions for the simulated ratoon cropped-plant crop and for the single cropped-plant crop, from 1939-1978, Temple, Texas. Field Capacity = 15 cm. 2. Grain yield cumulative probability distributions... initial values of soil water, from 1939-1978, Temple, Texas. Field Capacity = 20 cm. 63 LIST OF TABLES Table 1. Simulation Series I. Comparison of the Hydrologic Components and Crop Yields for Forty Years (1939-1978). 2. Simulation Series II...

Stinson, David Lawrence

1979-01-01T23:59:59.000Z

253

The Signature of Primordial Grain Growth in the Polarized Light of the AU Mic Debris Disk  

E-Print Network [OSTI]

We have used the Hubble Space Telescope/ACS coronagraph to make polarization maps of the AU Mic debris disk. The fractional linear polarization rises monotonically from about 0.05 to 0.4 between 20 and 80 AU. The polarization is perpendicular to the disk, indicating that the scattered light originates from micron sized grains in an optically thin disk. Disk models, which simultaneously fit the surface brightness and polarization, show that the inner disk (< 40-50 AU) is depleted of micron-sized dust by a factor of more than 300, which means that the disk is collision dominated. The grains have high maximum linear polarization and strong forward scattering. Spherical grains composed of conventional materials cannot reproduce these optical properties. A Mie/Maxwell-Garnett analysis implicates highly porous (91-94%) particles. In the inner Solar System, porous particles form in cometary dust, where the sublimation of ices leaves a "bird's nest" of refractory organic and silicate material. In AU Mic, the grain porosity may be primordial, because the dust "birth ring" lies beyond the ice sublimation point. The observed porosities span the range of values implied by laboratory studies of particle coagulation by ballistic cluster-cluster aggregation. To avoid compactification, the upper size limit for the parent bodies is in the decimeter range, in agreement with theoretical predictions based on collisional lifetime arguments. Consequently, AU Mic may exhibit the signature of the primordial agglomeration process whereby interstellar grains first assembled to form macroscopic objects.

James R. Graham; Paul G. Kalas; Brenda C. Matthews

2006-09-12T23:59:59.000Z

254

SIZE AND SURFACE AREA OF ICY DUST AGGREGATES AFTER A HEATING EVENT AT A PROTOPLANETARY NEBULA  

SciTech Connect (OSTI)

The activity of a young star rises abruptly during an FU Orionis outburst. This event causes a temporary temperature increase in the protoplanetary nebula. H{sub 2}O icy grains are sublimated by this event, and silicate cores embedded inside the ice are ejected. During the high-temperature phase, the silicate grains coagulate to form silicate core aggregates. After the heating event, the temperature drops, and the ice recondenses onto the aggregates. I determined numerically the size distribution of the ice-covered aggregates. The size of the aggregates exceeds 10 {mu}m around the snow line. Because of the migration of the ice to large aggregates, only a small fraction of the silicate core aggregate is covered with H{sub 2}O ice. After the heating event, the surface of an ice-covered aggregate is totally covered by silicate core aggregates. This might reduce the fragmentation velocity of aggregates when they collide. It is possible that the covering silicate cores shield the UV radiation field which induces photodissociation of H{sub 2}O ice. This effect may cause the shortage of cold H{sub 2}O vapor observed by Herschel.

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

2013-03-01T23:59:59.000Z

255

Quartz grain-size and grain-shape variation in the surface sediments of Galveston Island, Texas  

E-Print Network [OSTI]

transect line. Location of additional beach and fore-island dune samples. Sampling procedures at these locations are thoroughly described in the text. The samples field identification numbers are included in Appendices A and B, The samples are listed... progressively from the low-tide limit of the forebeach through the most landward dune sample under the corresponding sample location number (1 through 13). 24 O O Transect 3 sample location. The top portion is an enlarge- ment of the boxed area labeled T3...

George, Lawrence Matthew

1986-01-01T23:59:59.000Z

256

Linking Grain Boundary Structure and Composition to Intergranular Stress Corrosion Cracking of Austenitic Stainless Steels  

SciTech Connect (OSTI)

Grain boundary structure and composition is assessed in austenitic stainless steels along with its influence on intergranular stress corrosion cracking (IGSCC) in high-temperature water. Brief examples are presented illustrating effects of grain boundary character and segregation on behavior in specific light-water-reactor environments. Although grain boundary engineering can produce an increased fraction of special boundaries in austenitic stainless alloys, practical benefits depend on the boundary orientation distribution. It is critical to recognize that only coherent sigma 3s appear to be resistant to SCC and the behavior of other low sigma boundaries is uncertain. Grain boundary composition can have a dominant effect on IGSCC under certain conditions, but altered interfacial chemistry is not required for cracking. In high-potential oxidizing environments, IGSCC susceptibility is a direct function of the boundary Cr concentration. Non-equilibrium thermal segregation of Cr and Mo is often present in millannealed stainless steels and may influence cracking susceptibility. This initial grain boundary composition alters subsequent radiation-induced segregation and delays irradiation-assisted SCC susceptibility to higher doses. Other alloying elements and impurities in 300-series stainless steels have been seen to enrich grain boundaries, but few have any significant impact on IGSCC susceptibility. One exception is Si that strongly segregates during irradiation. recent results suggest that Si may accelerate crack propagation in both low- and high-potential water environments. Critical research is still needed to isolate individual grain boundary characteristics and quantitatively link to IGSCC.

Bruemmer, Stephen M.

2004-08-10T23:59:59.000Z

257

C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth  

E-Print Network [OSTI]

Infrared ~5--35 um spectra for 40 solar-mass T Tauri stars and 7 intermediate-mass Herbig Ae stars with circumstellar disks were obtained using the Spitzer Space Telescope as part of the c2d IRS survey. This work complements prior spectroscopic studies of silicate infrared emission from disks, which were focused on intermediate-mass stars, with observations of solar-mass stars limited primarily to the 10 um region. The observed 10 and 20 um silicate feature strengths/shapes are consistent with source-to-source variations in grain size. A large fraction of the features are weak and flat, consistent with um-sized grains indicating fast grain growth (from 0.1--1.0 um in radius). In addition, approximately half of the T Tauri star spectra show crystalline silicate features near 28 and 33 um indicating significant processing when compared to interstellar grains. A few sources show large 10-to-20 um ratios and require even larger grains emitting at 20 um than at 10 um. This size difference may arise from the difference in the depth into the disk probed by the two silicate emission bands in disks where dust settling has occurred. The 10 um feature strength vs. shape trend is not correlated with age or Halpha equivalent width, suggesting that some amount of turbulent mixing and regeneration of small grains is occurring. The strength vs. shape trend is related to spectral type, however, with M stars showing significantly flatter 10 um features (larger grain sizes) than A/B stars. The connection between spectral type and grain size is interpreted in terms of the variation in the silicate emission radius as a function of stellar luminosity, but could also be indicative of other spectral-type dependent factors (e.g, X-rays, UV radiation, stellar/disk winds, etc.).

J. E. Kessler-Silacci; J. -C. Augereau; C. P. Dullemond; V. Geers; F. Lahuis; N. J. Evans II; E. F. van Dishoeck; G. A. Blake; A. C. A. Boogert; J. Brown; J. K. Jorgensen; C. Knez; K. M. Pontoppidan

2005-11-02T23:59:59.000Z

258

A thermal spike model of grain growth under irradiation D. Kaoumi,1,a  

E-Print Network [OSTI]

. Birtcher2 1 Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, 227 Reber. This results in a power law expression relating the average grain size with the ion dose with an exponent equal the behavior of ma- terials in nuclear reactors and the behavior of thin-film solid state devices

Motta, Arthur T.

259

Coarse-grained Classification of Web Sites by Their Structural Properties  

E-Print Network [OSTI]

Coarse-grained Classification of Web Sites by Their Structural Properties Christoph Lindemann properties which reflect the functionality of a Web site. These structural properties consider the size, the organization, the composition of URLs, and the link structure of Web sites. Opposed to previous work, we

Lindemann, Christoph

260

Grain shape variations in late pleistocene and holocene fluvial and shelf sands in the northwestern Gulf of Mexico, and the relationship to source and shelf paleogeography  

E-Print Network [OSTI]

petrologic province as a "complex of sediments which by their geographical distribution, age and origin form a natural unit. " Provinces in the northwestern Gulf of Mexico, as in other areas have been determined by heavy mineral distri- butions... and Poole (1960). After testing and confirming that grain shape distributions can be used with as much success as heavy mineral distributions to determine sedimentary provinces, the technique was applied to the outer continen- tal shelf. Using grain...

Withers, Katrina Diane

1984-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

Characterization of ultra-fine grained aluminum produced by accumulative back extrusion (ABE)  

SciTech Connect (OSTI)

In the present work, the microstructural evolutions and microhardness of AA1050 subjected to one, two and three passes of accumulative back extrusion (ABE) were investigated. The microstructural evolutions were characterized using transmission electron microscopy. The results revealed that applying three passes of accumulative back extrusion led to significant grain refinement. The initial grain size of 47 {mu}m was refined to the grains of 500 nm after three passes of ABE. Increasing the number of passes resulted in more decrease in grain size, better microstructure homogeneity and increase in the microhardness. The cross-section of ABEed specimen consisted of two different zones: (i) shear deformation zone, and (ii) normal deformation zone. The microhardness measurements indicated that the hardness increased from the initial value of 31 Hv to 67 Hv, verifying the significant microstructural refinement via accumulative back extrusion. - Highlights: Black-Right-Pointing-Pointer A significant grain refinement can be achieved in AA1050, Al alloy by applying ABE. Black-Right-Pointing-Pointer Microstructural homogeneity of ABEed samples increased by increasing the number of ABE cycles. Black-Right-Pointing-Pointer A substantial increase in the hardness, from 31 Hv to 67 Hv, was recorded.

Alihosseini, H., E-mail: hamid.alihossieni@gmail.com [Mechanical Engineering Department, University of Tehran, Tehran (Iran, Islamic Republic of); Materials Science and Engineering Department, Engineering School, Amirkabir University, Tehran (Iran, Islamic Republic of); Faraji, G.; Dizaji, A.F. [Mechanical Engineering Department, University of Tehran, Tehran (Iran, Islamic Republic of); Dehghani, K. [Materials Science and Engineering Department, Engineering School, Amirkabir University, Tehran (Iran, Islamic Republic of)

2012-06-15T23:59:59.000Z

262

Surface and grain boundary scattering in nanometric Cu thin films: A quantitative analysis including twin boundaries  

SciTech Connect (OSTI)

The relative contributions of various defects to the measured resistivity in nanocrystalline Cu were investigated, including a quantitative account of twin-boundary scattering. It has been difficult to quantitatively assess the impact twin boundary scattering has on the classical size effect of electrical resistivity, due to limitations in characterizing twin boundaries in nanocrystalline Cu. In this study, crystal orientation maps of nanocrystalline Cu films were obtained via precession-assisted electron diffraction in the transmission electron microscope. These orientation images were used to characterize grain boundaries and to measure the average grain size of a microstructure, with and without considering twin boundaries. The results of these studies indicate that the contribution from grain-boundary scattering is the dominant factor (as compared to surface scattering) leading to enhanced resistivity. The resistivity data can be well-described by the combined FuchsSondheimer surface scattering model and MayadasShatzkes grain-boundary scattering model using Matthiessen's rule with a surface specularity coefficient of p?=?0.48 and a grain-boundary reflection coefficient of R?=?0.26.

Barmak, Katayun [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 and Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Darbal, Amith [Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Ganesh, Kameswaran J.; Ferreira, Paulo J. [Materials Science and Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712 (United States); Rickman, Jeffrey M. [Department of Materials Science and Engineering and Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Sun, Tik; Yao, Bo; Warren, Andrew P.; Coffey, Kevin R., E-mail: kb2612@columbia.edu [Department of Materials Science and Engineering, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States)

2014-11-01T23:59:59.000Z

263

Heavy Element Abundances in Presolar Silicon Carbide Grains from Low-Metallicity AGB Stars  

E-Print Network [OSTI]

Primitive meteorites contain small amounts of presolar minerals that formed in the winds of evolved stars or in the ejecta of stellar explosions. Silicon carbide is the best studied presolar mineral. Based on its isotopic compositions it was divided into distinct populations that have different origins: Most abundant are the mainstream grains which are believed to come from 1.5-3 Msun AGB stars of roughly solar metallicitiy. The rare Y and Z grains are likely to come from 1.5-3 Msun AGB stars as well, but with subsolar metallicities (0.3-0.5x solar). Here we report on C and Si isotope and trace element (Zr, Ba) studies of individual, submicrometer-sized SiC grains. The most striking results are: (1) Zr and Ba concentrations are higher in Y and Z grains than in mainstream grains, with enrichments relative to Si and solar of up to 70x (Zr) and 170x (Ba), respectively. (2) For the Y and Z grains there is a positive correlation between Ba concentrations and amount of s-process Si. This correlation is well explain...

Hoppe, P; Vollmer, C; Groener, E; Heck, P R; Gallino, R; Amari, S; 10.1071/AS08033

2009-01-01T23:59:59.000Z

264

Effects of Transition Metals on the Grain Boundary Cohesion in...  

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

Transition Metals on the Grain Boundary Cohesion in Tungsten. Effects of Transition Metals on the Grain Boundary Cohesion in Tungsten. Abstract: We report on the effects of...

265

Topological analysis of the grain boundary space  

E-Print Network [OSTI]

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

Patala, Srikanth

2011-01-01T23:59:59.000Z

266

Electric Dipole Radiation from Spinning Dust Grains  

E-Print Network [OSTI]

We discuss the rotational excitation of small interstellar grains and the resulting electric dipole radiation from spinning dust. Attention is given to excitation and damping of rotation by: collisions with neutrals; collisions with ions; plasma drag; emission of infrared radiation; emission of microwave radiation; photoelectric emission; and formation of H_2 on the grain surface. We introduce dimensionless functions F and G which allow direct comparison of the contributions of different mechanisms to rotational drag and excitation. Emissivities are estimated for dust in different phases of the interstellar medium, including diffuse HI, warm HI, low-density photoionized gas, and cold molecular gas. Spinning dust grains can explain much, and perhaps all, of the 14-50 GHz background component recently observed in CBR studies. It should be possible to detect rotational emission from small grains by ground-based observations of molecular clouds.

B. T. Draine; A. Lazarian

1998-02-18T23:59:59.000Z

267

Correcting Iron Deficiencies in Grain Sorghum  

E-Print Network [OSTI]

Until grain sorghum develops an extensive root system, young plants may be unable to obtain enough ferrous iron to maintain normal growth. This publication offers strategies for avoiding, identifying and correcting iron deficiencies....

Livingston, Stephen; Coffman, Cloyce G.; Unruh, L. G.

1996-02-20T23:59:59.000Z

268

Greenbug-resistance Studies with Small Grains.  

E-Print Network [OSTI]

insects. Such varieties may not be immune from attack, but insect populations increase on them more slowly; therefore, they are more readily controlled with chemicals when necessary. Greenbug-resistance studies were initiated at Substation No. 6.... Gardenhire and D. E. Weibel* HE GREENBUG (Toxoptera (Rond.)), among several aphids that attack small grains, is one of the most damaging insects of small- grain crops in the United States. Fifteen serious outbreaks have oc- curred since 1882, 10...

Chada, H. L.; Atkins, I. M.; Gardenhire, J. H.; Weibl, D. E.

1961-01-01T23:59:59.000Z

269

Microstructure and mechanical behavior of neutron irradiated ultrafine grained ferritic steel  

SciTech Connect (OSTI)

Neutron irradiation effects on ultra-fine grain (UFG) low carbon steel prepared by equal channel angular pressing (ECAP) has been examined. Counterpart samples with conventional grain (CG) sizes have been irradiated alongside with the UFG ones for comparison. Samples were irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) to 1.24 dpa. Atom probe tomography revealed manganese, silicon-enriched clusters in both ECAP and CG steel after neutron irradiation. X-ray quantitative analysis showed that dislocation density in CG increased after irradiation. However, no significant change was observed in UFG steel revealing better radiation tolerance.

Ahmad Alsabbagh; Apu Sarkar; Brandon Miller; Jatuporn Burns; Leah Squires; Douglas Porter; James I. Cole; K. L. Murty

2014-10-01T23:59:59.000Z

270

Dust filtration at gap edges: Implications for the spectral energy distributions of discs with embedded planets  

E-Print Network [OSTI]

The spectral energy distributions (SEDs) of some T Tauri stars display a deficit of near-IR flux that could be a consequence of an embedded Jupiter-mass planet partially clearing an inner hole in the circumstellar disc. Here, we use two-dimensional numerical simulations of the planet-disc interaction, in concert with simple models for the dust dynamics, to quantify how a planet influences the dust at different radii within the disc. We show that pressure gradients at the outer edge of the gap cleared by the planet act as a filter - letting particles smaller than a critical size through to the inner disc while holding back larger particles in the outer disc. The critical particle size depends upon the disc properties, but is typically of the order of 10 microns. This filtration process will lead to discontinuous grain populations across the planet's orbital radius, with small grains in the inner disc and an outer population of larger grains. We show that this type of dust population is qualitatively consistent with SED modelling of systems that have optically thin inner holes in their circumstellar discs. This process can also produce a very large gas-to-dust ratio in the inner disc, potentially explaining those systems with optically thin inner cavities that still have relatively high accretion rates.

W. K. M. Rice; Philip J. Armitage; Kenneth Wood; Giuseppe Lodato

2006-09-29T23:59:59.000Z

271

Short-time beta grain growth kinetics for a conventional titanium alloy  

SciTech Connect (OSTI)

The kinetics of beta grain growth during short-time, supertransus heat treatment of Ti-5Al-4V were determined using a salt-pot technique. The finite-time, subtransus temperature transient during salt-pot heating was quantified through measurements of the heat transfer coefficient characterizing conduction across the salt-titanium interface and a simple heat conduction analysis which incorporated this heat transfer coefficient. Grain size versus time data adjusted to account for the subtransus temperature transient were successfully fit to the parabolic grain growth law d{sup n} {minus} d{sub 0}{sup n} = kt exp({minus}Q/RT) using an exponent n equal to 2.0. Comparison of the present results to rapid, continuous heat treatment data in the literature for a similar titanium alloy revealed a number of semi-quantitative similarities.

Semiatin, S.L. [WL/MLLN, Wright-Patterson AFB, OH (United States). Materials Directorate] [WL/MLLN, Wright-Patterson AFB, OH (United States). Materials Directorate; Soper, J.C. [Wright State Univ., Dayton, OH (United States)] [Wright State Univ., Dayton, OH (United States); Sukonnik, I.M. [Texas Instruments, Attleboro, MA (United States)] [Texas Instruments, Attleboro, MA (United States)

1996-05-01T23:59:59.000Z

272

Metal precipitation at grain boundaries in silicon: Dependence on grain boundary character and dislocation decoration  

E-Print Network [OSTI]

are combined to determine the dependence of metal silicide precipitate formation on grain boundary character and microstructure in multicrystalline silicon mc-Si . Metal silicide precipitate decoration is observed to increase the local metal silicide precipitate concentrations at various types of grain boundaries, identifying clear

273

Internetwork chromospheric bright grains observed with IRIS  

E-Print Network [OSTI]

The Interface Region Imaging Spectrograph (IRIS) reveals small-scale rapid brightenings in the form of bright grains all over coronal holes and the quiet sun. These bright grains are seen with the IRIS 1330 \\AA, 1400 \\AA\\ and 2796 \\AA\\ slit-jaw filters. We combine coordinated observations with IRIS and from the ground with the Swedish 1-m Solar Telescope (SST) which allows us to have chromospheric (Ca II 8542 \\AA, Ca II H 3968 \\AA, H\\alpha, and Mg II k 2796 \\AA), and transition region (C II 1334 \\AA, Si IV 1402) spectral imaging, and single-wavelength Stokes maps in Fe I 6302 \\AA at high spatial (0.33"), temporal and spectral resolution. We conclude that the IRIS slit-jaw grains are the counterpart of so-called acoustic grains, i.e., resulting from chromospheric acoustic waves in a non-magnetic environment. We compare slit-jaw images with spectra from the IRIS spectrograph. We conclude that the grain intensity in the 2796 \\AA\\ slit-jaw filter comes from both the Mg II k core and wings. The signal in the C II ...

Martnez-Sykora, Juan; Carlsson, Mats; De Pontieu, Bart; Pereira, Tiago M D; Boerner, Paul; Hurlburt, Neal; Kleint, Lucia; Lemen, James; Tarbell, Ted D; Title, Alan; Wuelser, Jean-Pierre; Hansteen, Viggo H; Golub, Leon; McKillop, Sean; Reeves, Kathy K; Saar, Steven; Testa, Paola; Tian, Hui; Jaeggli, Sarah; Kankelborg, Charles

2015-01-01T23:59:59.000Z

274

algorithm population sizing: Topics by E-print Network  

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

CiteSeer Summary: Deciding the appropriate population size and number of islands for distributed island-model genetic algorithms is often critical to the algorithms success. This...

275

PROPERTIES OF NEWLY FORMED DUST GRAINS IN THE LUMINOUS TYPE IIn SUPERNOVA 2010jl  

SciTech Connect (OSTI)

Supernovae (SNe) have been proposed to be the main production sites of dust grains in the universe. However, our knowledge of their importance to dust production is limited by observationally poor constraints on the nature and amount of dust particles produced by individual SNe. In this paper, we present a spectrum covering optical through near-Infrared (NIR) light of the luminous Type IIn supernova 2010jl around one and a half years after the explosion. This unique data set reveals multiple signatures of newly formed dust particles. The NIR portion of the spectrum provides a rare example where thermal emission from newly formed hot dust grains is clearly detected. We determine the main population of the dust species to be carbon grains at a temperature of ?1350-1450 K at this epoch. The mass of the dust grains is derived to be ?(7.5-8.5) 10{sup 4} M{sub ?}. Hydrogen emission lines show wavelength-dependent absorption, which provides a good estimate of the typical size of the newly formed dust grains (?< 0.1 ?m, and most likely ?< 0.01 ?m). We believe the dust grains were formed in a dense cooling shell as a result of a strong SN-circumstellar media (CSM) interaction. The dust grains occupy ?10% of the emitting volume, suggesting an inhomogeneous, clumpy structure. The average CSM density must be ?> 3 10{sup 7} cm{sup 3}, corresponding to a mass loss rate of ?> 0.02 M{sub ?} yr{sup 1} (for a mass loss wind velocity of ?100 km s{sup 1}). This strongly supports a scenario in which SN 2010jl and probably other luminous SNe IIn are powered by strong interactions within very dense CSM, perhaps created by Luminous-Blue-Variable-like eruptions within the last century before the explosion.

Maeda, K.; Nozawa, T.; Folatelli, G.; Moriya, T. J.; Nomoto, K.; Bersten, M.; Quimby, R. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Sahu, D. K.; Anupama, G. C. [Indian Institute of Astrophysics, Koramangala, Bangalore 560 034 (India); Minowa, Y.; Pyo, T.-S. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States); Motohara, K.; Kitagawa, Y. [Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Ueno, I.; Kawabata, K. S.; Yamanaka, M. [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kozasa, T. [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Iye, M., E-mail: keiichi.maeda@ipmu.jp [National Astronomical Observatory, Mitaka, Tokyo (Japan)

2013-10-10T23:59:59.000Z

276

Aphids on Texas Small Grains and sorghum.  

E-Print Network [OSTI]

, primarily wheat, provide the major winter host of greenbugs; sorghum is the major summer host in Texas. John songrass and other grasses serve as interim hosts when the growth of small grains and sorghum do not overlap. Oats may host greenbugs, but tends... found on small grains within the tightly curled leaf of the newest growth of the plant. As is the case with greenbugs, small populations of the Russian wheat aphid are not readily visible on casual observation. Infested plants some times have purple...

Hoelscher, Clifford E.; Thomas, John G.; Teetes, George L.

1987-01-01T23:59:59.000Z

277

Development of large Grain/Single Crystal Niobium Cavity Technology at Jefferson Lab  

SciTech Connect (OSTI)

Approximately two years ago we started to develop high performance niobium accelerating cavities based on large grain or single crystal high purity niobium. We have fabricated and tested 15 single cell cavities of various shapes and frequencies between 1300 MHz and 2300 MHz using material from a total of 9 different very large grain niobium ingots from four niobium suppliers. The materials differed not only in grain sizes, but also in RRR ? value and in the amount of Ta contained in the material. In one ingot supplied by CBMM the central grain exceeded 7 inches in diameter and this was used to fabricate two 2.2 GHz cavities. A single crystal 1300 MHz mono-cell cavity was also produced at DESY by rolling out a single crystal to the size required for this cavity. It was sent to Jlab for surface treatment and testing. In addition, we have fabricated three 7-cell cavities: two of the Jlab high gradient (HG) shape and one of the ILC Low Loss shape. Two 9-cell TESLA shape cavities are presently in fabrication at Jlab and are close to completion.

Peter Kneisel; J. Sekutowicz; T. Carneiro; G. Ciovati

2006-10-31T23:59:59.000Z

278

Equal-channel angular pressing of commercial aluminum alloys: Grain refinement, thermal stability and tensile properties  

SciTech Connect (OSTI)

Using equal-channel angular (ECA) pressing at room temperature, the grain sizes of six different commercial aluminum-based alloys (1100, 2024, 3004, 5083, 6061, and 7075) were reduced to within the submicrometer range. These grains were reasonably stable up to annealing temperatures of {approximately} 200 C and the submicrometer grains were retained in the 2024 and 7075 alloys to annealing temperatures of 300 C. Tensile testing after ECA pressing through a single pass, equivalent to the introduction of a strain of {approximately}1, showed there is a significant increase in the values of the 0.2 pct proof stress and the ultimate tensile stress (UTS) for each alloy with a corresponding reduction in the elongations to failure. It is demonstrated that the magnitudes of these stresses scale with the square rot of the Mg content in each alloy. Similar values for the proof stresses and the UTS were attained at the same equivalent strains in samples subjected to cold rolling, but the elongations to failure were higher after ECA pressing to equivalent strains >1 because of the introduction of a very small grain size. Detailed results for the 1100 and 3004 alloys show good agreement with the standard Hall-Petch relationship.

Horita, Zenji; Fujinami, Takayoshi; Nemoto, Minoru; Langdon, T.G.

2000-03-01T23:59:59.000Z

279

4-D XRD for strain in many grains using triangulation  

SciTech Connect (OSTI)

Determination of the strains in a polycrystalline materialusing 4-D XRD reveals sub-grain and grain-to-grain behavior as a functionof stress. Here 4-D XRD involves an experimental procedure usingpolychromatic micro-beam X-radiation (micro-Laue) to characterizepolycrystalline materials in spatial location as well as with increasingstress. The in-situ tensile loading experiment measured strain in a modelaluminum-sapphire metal matrix composite using the Advanced Light Source,Beam-line 7.3.3. Micro-Laue resolves individual grains in thepolycrystalline matrix. Results obtained from a list of grains sorted bycrystallographic orientation depict the strain states within and amongindividual grains. Locating the grain positions in the planeperpendicular to the incident beam is trivial. However, determining theexact location of grains within a 3-D space is challenging. Determiningthe depth of the grains within the matrix (along the beam direction)involved a triangulation method tracing individual rays that producespots on the CCD back to the point of origin. Triangulation wasexperimentally implemented by simulating a 3-D detector capturingmultiple diffraction images while increasing the camera to sampledistance. Hence by observing the intersection of rays from multiple spotsbelonging to the corresponding grain, depth is calculated. Depthresolution is a function of the number of images collected, grain to beamsize ratio, and the pixel resolution of the CCD. The 4DXRD methodprovides grain morphologies, strain behavior of each grain, andinteractions of the matrix grains with each other and the centrallylocated single crystal fiber.

Bale, Hrishikesh A.; Hanan, Jay C.; Tamura, Nobumichi

2006-12-31T23:59:59.000Z

280

Growth of Smaller Grain Attached on Larger One: Algorithm to Overcome Unphysical Overlap between Grain  

E-Print Network [OSTI]

As a smaller grain, which is attached on larger one, is growing, it pushes also the larger one and other grains in its surrounding. In a simulation of similar system, repulsive force such as contact force based on linear spring-dashpot model can not accommodate this situation when cell growing rate is faster than simulation time step, since it produces sudden large overlap between grains that makes unphysical result. An algorithm that preserves system linear momentum by introducing additional velocity induced by cell growth is presented in this work. It should be performed in an implicit step. The algorithm has successfully eliminated unphysical overlap.

Acep Purqon; Sparisoma Viridi

2014-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

CROP & SOIL SCIENCES Small Grain Breeding  

E-Print Network [OSTI]

CROP & SOIL SCIENCES Small Grain Breeding Committee Membership Dr. Paul Raymer - committee chair Dr. Scott Jackson Department of Crop & Soil Sciences Department of Crop & Soil Sciences University & Soil Sciences Department of Horticulture University of Georgia University of Georgia 2360 Rainwater Rd

Arnold, Jonathan

282

Large grain cavities from pure niobium ingot  

DOE Patents [OSTI]

Niobium cavities are fabricated by the drawing and ironing of as cast niobium ingot slices rather than from cold rolled niobium sheet. This method results in the production of niobium cavities having a minimum of grain boundaries at a significantly reduced cost as compared to the production of such structures from cold rolled sheet.

Myneni, Ganapati Rao (Yorktown, VA); Kneisel, Peter (Williamsburg, VA); Cameiro, Tadeu (McMurray, PA)

2012-03-06T23:59:59.000Z

283

The Grain Milling Oilseed Processing Industry  

E-Print Network [OSTI]

& 10 Prepared by: Sondra Rademacher ­ Business Service Specialist, Mankato, Mn. Garey Ferguson ­ Business Service Specialist, Fairmont, Mn. Sue Wold ­ Business Services Specialist, Faribault, Mn. David-19 Diamond of Advantage for Grain and Oilseed Processing Industry Attachment A Minnesota's Food Manufacturing

Levinson, David M.

284

Mechanical alignment of suprathermally rotating grains  

E-Print Network [OSTI]

It is shown that mechanical alignment of grains can be efficient for grains rotating suprathermally, i.e. with kinetic energy substantially exceeding $k$ (the Boltzmann constant) over any temperature in the system. The paper studies suprathermal rotation caused by H$_{2}$ formation and the alignment that takes place due to crossover events. Gaseous bombardment in the course of a crossover as well as both gaseous friction and poisoning of active sites are shown to produce alignment. The first type of alignment happens due to the angular momentum deposited by a corpuscular flux with a grain, the second is caused by the change of the mean time back to crossover due to the interaction with a gaseous flux. We show that the two processes act as to decrease the grain cross section in respect to the flux and we find the Rayleigh reduction factor for the joint action of the two processes as well as the range of applicability of each of the processes. Our study indicates that mechanical alignment can be more widely spread than it is generally accepted.

A. Lazarian

1995-05-01T23:59:59.000Z

285

E-Print Network 3.0 - adjustable pore size Sample Search Results  

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

by the rigid material alone. The difference in pore size distribution before and after heat... are observed in the larger pore range of the pore size distribution while the...

286

Studies of physical characteristics and animal response to reconstituted sorghum grain  

E-Print Network [OSTI]

USSION SUMMAR Y Z3 53 67 LITERATURE CITED 71 LIST OF TABLES Table Page Index for estimating average particle size of ground sorghum grain. 18 Feedlot performance of bulls fed two feed mix- tures for 93 days (growing period), College Station..., 1967, 24 Feedlot performance of bulls fed four feed mix- tures for 102 days (finishing period), College Station, 1967. 26 Analysis of variance of daily gain 27 t- Test for differences in average daily gain Analysis of variance for average particle...

Florence, Harold Douglas

1968-01-01T23:59:59.000Z

287

Grain Growth Behavior, Tensile Impact Ductility, and Weldability of Cerium-Doped Iridium Alloys  

SciTech Connect (OSTI)

An iridium alloy doped with small amounts of cerium and thorium is being developed as a potential replacement for the iridium-based DOP-26 alloy (doped with thorium only) that is currently used by the National Aeronautics and Space Administration (NASA) for cladding and post-impact containment of the radioactive fuel in radioisotope thermoelectric generator (RTG) heat sources which provide electric power for interplanetary spacecraft. This report summarizes results of studies conducted to date under the Iridium Alloy Characterization and Development subtask of the Radioisotope Power System Materials Production and Technology Program to characterize the properties of the iridium-based alloy (designated as DOP-40) containing both cerium and thorium. Included within this report are data on grain growth of sheet material in vacuum and low-pressure oxygen environments, grain growth in vacuum of the clad vent set cup material, weldability, and the effect of grain size and test temperature on tensile properties. Where applicable, data for the DOP-26 alloy are included for comparison. Both grain size and grain-boundary cohesion affect the ductility of iridium alloys. In this study it was found that cerium and thorium, when added together, refine grain size more effectively than when thorium is added by itself (especially at high temperatures). In addition, the effect of cerium additions on grain-boundary cohesion is similar to that of thorium. Mechanical testing at both low ({approx} 10{sup -3}s{sup -1}) and high ({approx} 10{sup -3}s{sup -1}) strain rates showed that the Ce/Th-doped alloys have tensile ductilities that are as good or better than the DOP-26 alloy. The general conclusion from these studies is that cerium can be used to replace some of the radioactive thorium currently used in DOP-26 while maintaining or improving its metallurgical properties. The current DOP-26 alloy meets all requirements for cladding the radioactive fuel in the RTG heat source, but the new DOP-40 alloy could serve as a back-up alloy to be used if the costs of refining, handling, and transporting DOP-26 become prohibitively high.

McKamey, C.G.

2002-05-28T23:59:59.000Z

288

Strengthening of metallic alloys with nanometer-size oxide dispersions  

DOE Patents [OSTI]

Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains.

Flinn, John E. (Idaho Falls, ID); Kelly, Thomas F. (Madison, WI)

1999-01-01T23:59:59.000Z

289

Strengthening of metallic alloys with nanometer-size oxide dispersions  

DOE Patents [OSTI]

Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains. 20 figs.

Flinn, J.E.; Kelly, T.F.

1999-06-01T23:59:59.000Z

290

Increasing the Consumption of Whole Grain Foods in School Meals  

E-Print Network [OSTI]

nutritious meals in their cafeterias, while maintaining customer acceptance of the foods. Whether or not students consume whole grains determines if these foods are served again. Input from participants determined which whole grain were foods tested...

Warren, Cynthia Ann

2011-08-08T23:59:59.000Z

291

Ground Versus Unground Grain for Lactating Dairy Cows.  

E-Print Network [OSTI]

. Table 10. Effects of Feeding Ground versus Whole Grain on High versus Low Producing Cows. Productive Values of Whole Grains Experiment Numbers Corn Experiment No. 1.. .... .... Corn Experiment No. 2.. ..... Oat Experiment No. 1.. Oat Experiment hTo...

Darnell, A. L. (Albert Laurie); Copeland, O. C. (Orlin Cephas)

1936-01-01T23:59:59.000Z

292

Grain-scale Comminution and Alteration of Arkosic Rocks in the Damage Zone of the San Andreas Fault at SAFOD  

E-Print Network [OSTI]

, the particle sizes are consistent with a power law distribution over the particle size range investigated (0.3 m fractal dimension, D) is found to increase with shear strain and volume fraction of laumontite. This overall increase...

Heron, Bretani

2012-02-14T23:59:59.000Z

293

Reading Acquisition, Developmental Dyslexia, and Skilled Reading Across Languages: A Psycholinguistic Grain Size Theory  

E-Print Network [OSTI]

Reading Acquisition, Developmental Dyslexia, and Skilled Reading Across Languages representations and accompanying differences in developmental reading strategies and the manifestation of dyslexia

Port, Robert

294

Grain size control and microstructural evolution in nanocrystalline Ni-W alloys  

E-Print Network [OSTI]

Nanocrystalline materials have been studied extensively over the past two decades because of their useful and interesting physical properties. In most cases, these properties derive from the fine characteristic length scale ...

Detor, Andrew J. (Andrew Joseph)

2007-01-01T23:59:59.000Z

295

Z .Chemical Geology 158 1999 173188 Grain size separation and sediment mixing in Arctic Ocean  

E-Print Network [OSTI]

' FBE . At the land­ocean transition the reduction of the particle velocity causes a deposition ages from the FBE reflect the age of the Siberian flood Z .basalt of about 220 Ma and the initial ratio samples from the western Laptev Sea Z . 143 144 west of 1208E fall between LME and FBE. Mixing

Schöne, Bernd R.

296

Retrieval of subpixel snow covered area, grain size, and albedo from MODIS Thomas H. Painter a,  

E-Print Network [OSTI]

the energy and mass balance of the snow cover are its spatial extent and albedo (Blschl, 1991; Dozier a Department of Geography, University of Utah, Salt Lake City, UT 84112, USA b Donald Bren School

Dozier, Jeff

297

EFFECT OF GRAIN SIZE ON THE ACOUSTIC EMISSION GENERATED DURING PLASTIC DEFORMATION OF COPPER  

E-Print Network [OSTI]

PLASTIC DEFORMATION OF COPPER J, Baram Materials Engineeringfrom plastically deformed copper specimens were analyzedrelated to the behavior of copper while undergoing plastic

Baram, J.

2011-01-01T23:59:59.000Z

298

Effect of Grain Size on Uranium(VI) Surface Complexation Kinetics and  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed NewcatalystNeutronEnvironmentZIRKLE FRUITYear 1MATERIALSTiO2(110).Adsorption

299

Suggestions for Controlling Insects in Farm-Stored Grain.  

E-Print Network [OSTI]

of Infestations When storing grain in farm facilities, provide the least favorable conditions for insect development. Store clean, sound grain with 12 percent or less moisture content. Grain cot;ltaining more moisture at tracts insects, promotes mold growth...IUUL; Z TA24S.7 8873 NO.1410 Suggestions B-1410 for Controlling Insects ? In Farm-Stored Grain The Texas A&M University System ? Texas Agricultural Extension Service JUN 2 0 2002 Zerle L. Carpenter . Director College Station...

Hamman, Philip J.

1982-01-01T23:59:59.000Z

300

Heartland Grain Fuels LP | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: Energy Resources Jump to: navigation,Ohio:Greer CountyCorridorPart A Permit ApplicationHeartlandHeartland Grain

Note: This page contains sample records for the topic "grain 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

Midwest Grain Processors MGP | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbH JumpSprings, Vermont: Energy ResourcesisMidway,Midwest Grain

302

Golden Grain Energy LLC | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: Energy Resources Jump to: navigation,Ohio: Energy Resources Jump to:Gloria GlensCalifornia:Glades, Florida:Grain

303

Managing Insect and Mite Pests of Texas Small Grains  

E-Print Network [OSTI]

wheat mite Winter grain mite English grain aphid Bird cherry-oat aphid Wheat curl mite Russian wheat aphid Army cutworm Aug Sept Oct Nov Dec Jan Feb Mar Apr May Jun Jul Figure 1. The occurrence and development of different small grains pests... .................................................................................................................................. 11 Russian wheat aphid ............................................................................................................... 13 Bird cherry oat aphid...

Patrick, Carl D.; Knutson, Allen E.

2006-07-05T23:59:59.000Z

304

ANNIVERSARY REVIEW Grain boundary energy anisotropy: a review  

E-Print Network [OSTI]

energy (B) gained when the two surfaces are brought together and new bonds are formed. The grain boundaryANNIVERSARY REVIEW Grain boundary energy anisotropy: a review Gregory S. Rohrer Received: 29 April 2011 Abstract This paper reviews findings on the anisotropy of the grain boundary energies. After

Rohrer, Gregory S.

305

RFID BASED GRAIN AND OIL PRODUCTS TRACEABILITY1  

E-Print Network [OSTI]

RFID BASED GRAIN AND OIL PRODUCTS TRACEABILITY1 AND ITS COMPUTER IMPLEMENTATION Haiyan Hu ,*2 the study of the traceability of grain and oil products. Include the study contents, and a system we developed for traceability of grain and oil products, and the demonstration of the study. The system we

Boyer, Edmond

306

Nature of Nano-Sized Plutonium Particles in Soils at the Hanford Site  

SciTech Connect (OSTI)

The occurrence of plutonium dioxide (PuO2) either from direct deposition or from the precipitation of plutonium-bearing solutions in contaminated soils and sediments has been well described, particularly for the Hanford site in Washington State. However, past research has suggested that plutonium may exist in environmental samples at the Hanford site in chemical forms in addition to large size PuO2 particles and that these previously unidentified nano-sized particles maybe more reactive and thus more likely to influence the environmental mobility of Pu. Here we present evidence for the formation of nano-sized plutonium iron phosphate hydroxide structurally related to the rhabdophane group nanoparticles in 216-Z9 crib sediments from Hanford using transmission electron microscopy (TEM). The distribution and nature of these nanoparticles varied depending on the adjacent phases present. Fine electron probes were used to obtain electron diffraction and electron energy-loss spectra from specific phase regions of the 216-Z9 cribs specimens from fine-grained plutonium oxide and phosphate phases. Energy-loss spectra were used to evaluate the plutonium N4,5 (4d ? 5f ) and iron L2,3 absorption edges. The iron plutonium phosphate formation may depend on the local micro-environment in the sediments, availability of phosphate, and hence the distribution of these minerals may control long-term migration of Pu in the soil. This study also points to the utility of using electron beam methods for determining the identity of actinide phases and their association with other sediment phases.

Buck, Edgar C.; Moore, Dean A.; Czerwinski, Kenneth R.; Conradson, Steven D.; Batuk, Olga; Felmy, Andrew R.

2014-08-06T23:59:59.000Z

307

Strategy Guideline: HVAC Equipment Sizing  

SciTech Connect (OSTI)

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

308

Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making  

DOE Patents [OSTI]

A method of making a permanent magnet wherein 1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and 2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries. The crystallized particulates are consolidated at an elevated temperature to form a shape. During elevated temperature consolidation, the primary and secondary precipitates act to pin the grain boundaries and minimize deleterious grain growth that is harmful to magnetic properties.

McCallum, R. William (Ames, IA); Branagan, Daniel J. (Ames, IA)

1996-01-23T23:59:59.000Z

309

Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making  

DOE Patents [OSTI]

A method of making a permanent magnet is disclosed wherein (1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and (2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries. The crystallized particulates are consolidated at an elevated temperature to form a shape. During elevated temperature consolidation, the primary and secondary precipitates act to pin the grain boundaries and minimize deleterious grain growth that is harmful to magnetic properties. 33 figs.

McCallum, R.W.; Branagan, D.J.

1996-01-23T23:59:59.000Z

310

Characterization of grain boundary conductivity of spin-sprayed ferrites using scanning microwave microscope  

SciTech Connect (OSTI)

Grain boundary electrical conductivity of ferrite materials has been characterized using scanning microwave microscope. Structural, electrical, and magnetic properties of Fe{sub 3}O{sub 4} spin-sprayed thin films onto glass substrates for different length of growth times were investigated using a scanning microwave microscope, an atomic force microscope, a four-point probe measurement, and a made in house transmission line based magnetic permeameter. The real part of the magnetic permeability shows almost constant between 10 and 300?MHz. As the Fe{sub 3}O{sub 4} film thickness increases, the grain size becomes larger, leading to a higher DC conductivity. However, the loss in the Fe{sub 3}O{sub 4} films at high frequency does not increase correspondingly. By measuring the reflection coefficient s{sub 11} from the scanning microwave microscope, it turns out that the grain boundaries of the Fe{sub 3}O{sub 4} films exhibit higher electric conductivity than the grains, which contributes loss at radio frequencies. This result will provide guidance for further improvement of low loss ferrite materials for high frequency applications.

Myers, J.; Nicodemus, T.; Zhuang, Y., E-mail: yan.zhuang@wright.edu [Department of Electrical Engineering, Wright State University, Dayton, Ohio 45435 (United States); Watanabe, T.; Matsushita, N. [Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama (Japan); Yamaguchi, M. [Department of Electrical Engineering, Tohoku University, Sendai 980-8579 (Japan)

2014-05-07T23:59:59.000Z

311

Spectroscopic diagnostic for the mineralogy of large dust grains  

E-Print Network [OSTI]

We examine the thermal infrared spectra of large dust grains of different chemical composition and mineralogy. Strong resonances in the optical properties result in detectable spectral structure even when the grain is much larger than the wavelength at which it radiates. We apply this to the thermal infrared spectra of compact amorphous and crystalline silicates. The weak resonances of amorphous silicates at 9.7 and 18 micron virtually disappear for grains larger than about 10 micron. In contrast, the strong resonances of crystalline silicates produce emission dips in the infrared spectra of large grains; these emission dips are shifted in wavelength compared to the emission peaks commonly seen in small crystalline silicate grains. We discuss the effect of a fluffy or compact grain structure on the infrared emission spectra of large grains, and apply our theory to the dust shell surrounding Vega.

M. Min; C. Dominik; L. B. F. M. Waters

2003-10-30T23:59:59.000Z

312

What Grain Alignment can Tell about Circumstellar Disks and Comets  

E-Print Network [OSTI]

Grain alignment theory suggests that grains should be aligned in circumstellar regions and the observational data available supports this conclusion. We discuss the alignment of grains via (1) magnetic relaxation, (2) mechanical processes, and (3) radiative torques. We show that ferromagnetic relaxation is likely to be more important than superparamagnetic relaxation if the dust in circumstellar regions is similar to species recently captured in Earth atmosphere. Outflows and stellar winds provide grain streaming along magnetic field lines and therefore mechanical alignment competes with the ferromagnetic and radiative alignments. We estimate measures of grain alignment in circumstellar regions, comets and interplanetary space and conclude that in many circumstellar regions and in the interplanetary space radiative torques may constitue the major alignment mechanism which aligns grain longer axes perpendicular to the direction of magnetic field. Observations in submillimeter and microwave ranges are suggested as a means of disentangling effects of multiple scattering from those related to aligned grains.

Lazarian A

1998-11-03T23:59:59.000Z

313

The shape and composition of interstellar silicate grains  

E-Print Network [OSTI]

We investigate the composition and shape distribution of silicate dust grains in the interstellar medium. The effect of the amount of magnesium in the silicate lattice is studied. We fit the spectral shape of the interstellar 10 mu extinction feature as observed towards the galactic center. We use very irregularly shaped coated and non-coated porous Gaussian Random Field particles as well as a statistical approach to model shape effects. For the dust materials we use amorphous and crystalline silicates with various composition and SiC. The results of our analysis of the 10 mu feature are used to compute the shape of the 20 mu silicate feature and to compare this with observations. By using realistic particle shapes we are, for the first time, able to derive the magnesium fraction in interstellar silicates. We find that the interstellar silicates are highly magnesium rich (Mg/(Fe+Mg)>0.9) and that the stoichiometry lies between pyroxene and olivine type silicates. This composition is not consistent with that of the glassy material found in GEMS in interplanetary dust particles indicating that these are, in general, not unprocessed remnants from the interstellar medium. Also, we find a significant fraction of SiC (~3%). We discuss the implications of our results for the formation and evolutionary history of cometary and circumstellar dust. We argue that the fact that crystalline silicates in cometary and circumstellar grains are almost purely magnesium silicates is a natural consequence of our findings that the amorphous silicates from which they were formed were already magnesium rich.

M. Min; L. B. F. M. Waters; A. de Koter; J. W. Hovenier; L. P. Keller; F. Markwick-Kemper

2006-11-10T23:59:59.000Z

314

LBNL -42691 Leakage Diagnostics, Sealant Longevity, Sizing  

E-Print Network [OSTI]

LBNL - 42691 1 Leakage Diagnostics, Sealant Longevity, Sizing and Technology Transfer of or agreement with these findings, nor that of any CIEE sponsor. #12;LBNL - 42691 2 Leakage Diagnostics, Sealant of the Residential Thermal Distribution Systems research done by Lawrence Berkeley National Laboratory (LBNL

315

Grain quality impacts of prohibiting recombination recirculation dust at export grain elevators  

E-Print Network [OSTI]

such as those where grain moves from one belt conveyor to another, one auger to another, into and out of a bucket elevator, or into and out of storage bins. Typically, a cloud of dust is created at each transfer point. Since this dust cloud.... Dust ventilation is energy intensive and can account for a large portion (one-third to one-half) of an elevator's electrical energy cost (Whitelock, 1991). National Grain and Feed Association (1981) and National Materials Advisory Board (1982) have...

Spillmann, Daryl Drew

1992-01-01T23:59:59.000Z

316

Metal precipitation at grain boundaries in silicon: Dependence on grain boundary character and dislocation decoration  

SciTech Connect (OSTI)

Synchrotron-based analytical microprobe techniques, electron backscatter diffraction, and defect etching are combined to determine the dependence of metal silicide precipitate formation on grain boundary character and microstructure in multicrystalline silicon (mc-Si). Metal silicide precipitate decoration is observed to increase with decreasing atomic coincidence within the grain boundary plane (increasing {sigma} values). A few low-{sigma} boundaries contain anomalously high metal precipitate concentrations, concomitant with heavy dislocation decoration. These results provide direct experimental evidence that the degree of interaction between metals and structural defects in mc-Si can vary as a function of microstructure, with implications for mc-Si device performance and processing.

Buonassisi, T.; Istratov, A. A.; Pickett, M. D.; Marcus, M. A.; Ciszek, T. F.; Weber, E. R. [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2006-07-24T23:59:59.000Z

317

Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry-Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases  

SciTech Connect (OSTI)

Observations and model studies suggest a significant but highly non-linear role for halogens, primarily Cl and Br, in multiphase atmospheric processes relevant to tropospheric chemistry and composition, aerosol evolution, radiative transfer, weather, and climate. The sensitivity of global atmospheric chemistry to the production of marine aerosol and the associated activation and cycling of inorganic Cl and Br was tested using a size-resolved multiphase coupled chemistry/global climate model (National Center for Atmospheric Researchs Community Atmosphere Model (CAM); v3.6.33). Simulation results showed strong meridional and vertical gradients in Cl and Br species. The simulation reproduced most available observations with reasonable confidence permitting the formulation of potential mechanisms for several previously unexplained halogen phenomena including the enrichment of Br- in submicron aerosol, and the presence of a BrO maximum in the polar free troposphere. However, simulated total volatile Br mixing ratios were generally high in the troposphere. Br in the stratosphere was lower than observed due to the lack of long-lived organobromine species in the simulation. Comparing simulations using chemical mechanisms with and without reactive Cl and Br species demonstrated a significant temporal and spatial sensitivity of primary atmospheric oxidants (O3, HOx, NOx), CH4, and non-methane hydrocarbons (NMHCs) to halogen cycling. Simulated O3 and NOx were globally lower (65% and 35%, respectively, less in the planetary boundary layer based on median values) in simulations that included halogens. Globally, little impact was seen in SO2 and non-sea-salt SO42- processing due to halogens. Significant regional differences were evident: The lifetime of nss-SO42- was extended downwind of large sources of SO2. The burden and lifetime of DMS (and its oxidation products) were lower by a factor of 5 in simulations that included halogens, versus those without, leading to a 20% reduction in nss-SO42- in the southern hemisphere planetary boundary layer based on median values.

Long, M.; Keene, W. C.; Easter, Richard C.; Sander, Rolf; Liu, Xiaohong; Kerkweg, A.; Erickson, D.

2014-04-07T23:59:59.000Z

318

Thermodynamic consistency in variable-level coarse-graining of polymeric liquids  

E-Print Network [OSTI]

Numerically optimized reduced descriptions of macromolecular liquids often present thermodynamic inconsistency with atomistic level descriptions even if the total correlation function, i.e. the structure, appears to be in agreement. An analytical expression for the effective potential between a pair of coarse-grained units is derived starting from the first-principles Ornstein-Zernike equation, for a polymer liquid where each chain is represented as a collection of interpenetrating blobs, with a variable number of blobs, $n_b$, of size $N_b$. The potential is characterized by a long tail, slowly decaying with characteristic scaling exponent of $N_b^{1/4}$. This general result applies to any coarse-grained model of polymer melts with units larger than the persistence length, highlighting the importance of the long, repulsive, potential tail for the model to correctly predict both structural and thermodynamic properties of the macromolecular liquid.

Anthony J. Clark; Jay McCarty; Ivan Y. Lyubimov; Marina G. Guenza

2013-02-13T23:59:59.000Z

319

Grain boundary compositon in NiAl  

SciTech Connect (OSTI)

The high temperature strength and oxidation resistance of many transition metal aluminides makes these intermetallic materials attractive for high temperature applications. However, these aluminides are generally brittle at low temperatures and this restricts their technological applications. However, these aluminides are generally brittle at low temperatures and this restricts their technological applications. It has been demonstrated that the addition of more than 200 ppm of boron to the L1{sub 2}-ordered Ni{sub 3}Al changes the fracture behavior from intergranular to transgranular and increases the ductility. The B2-ordered NiAl nickel aluminide is particularly attractive because of its low density and high melting temperature. This aluminide also fractures intergranularly at room temperature. However, no improvement in ductility is observed with similar boron additions even though the intergranular fracture is suppressed and there is a significant increase in the yield strength. In this paper, the results of an atom probe field ion microscopy investigation of the compositions of the grain boundaries in undoped and boron-doped NiAl are presented. The suitability of the atom probe field ion microscopy technique for the characterization of boundaries has clearly been demonstrated in many previous investigations including the characterization of boron segregation to grain boundaries and other planar features in Ni{sub 3}Al.

Miller, M.K.; Jayaram, R.; Camus, P.P. (Metals and Ceramics Div., Oak Ridge National Lab., Oak Ridge, TN (US))

1992-02-15T23:59:59.000Z

320

PRAM C:a new programming environment for fine-grain and coarse-grain parallelism.  

SciTech Connect (OSTI)

In the search for ''good'' parallel programming environments for Sandia's current and future parallel architectures, they revisit a long-standing open question. Can the PRAM parallel algorithms designed by theoretical computer scientists over the last two decades be implemented efficiently? This open question has co-existed with ongoing efforts in the HPC community to develop practical parallel programming models that can simultaneously provide ease of use, expressiveness, performance, and scalability. Unfortunately, no single model has met all these competing requirements. Here they propose a parallel programming environment, PRAM C, to bridge the gap between theory and practice. This is an attempt to provide an affirmative answer to the PRAM question, and to satisfy these competing practical requirements. This environment consists of a new thin runtime layer and an ANSI C extension. The C extension has two control constructs and one additional data type concept, ''shared''. This C extension should enable easy translation from PRAM algorithms to real parallel programs, much like the translation from sequential algorithms to C programs. The thin runtime layer bundles fine-grained communication requests into coarse-grained communication to be served by message-passing. Although the PRAM represents SIMD-style fine-grained parallelism, a stand-alone PRAM C environment can support both fine-grained and coarse-grained parallel programming in either a MIMD or SPMD style, interoperate with existing MPI libraries, and use existing hardware. The PRAM C model can also be integrated easily with existing models. Unlike related efforts proposing innovative hardware with the goal to realize the PRAM, ours can be a pure software solution with the purpose to provide a practical programming environment for existing parallel machines; it also has the potential to perform well on future parallel architectures.

Brown, Jonathan Leighton; Wen, Zhaofang.

2004-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

Structural Dependence of Grain Boundary Resistance in Copper Nanowires  

SciTech Connect (OSTI)

The current choice of the interconnect metal in integrated circuits is copper due to its higher electrical conductivity and improved electromigration reliability in comparison with aluminum. However, with reducing feature sizes, the resistance of copper interconnects (lines) increases dramatically. Greater resistance will result in higher energy use, more heat generation, more failure due to electromigration, and slower switching speeds. To keep pace with the projected planar transistor density, the first challenge is to identify the dominant factors that contribute to the high interconnect resistance. Here we directly measure individual grain boundary (GB) resistances in copper nanowires with a one-to-one correspondence to the GB structure. The specific resistivities of particular GBs are measured using four-probe scanning tunneling microscopy (STM) to establish a direct link between GB structure and the resistance. High-angle random GBs contribute to a specific resistivity of about 25 10-12 cm2 for each boundary, while coincidence boundaries are significantly less-resistive than random boundaries. Thus, replacing random boundaries with coincidence ones would be a route to suppress the GB impact to the resistivity of polycrystalline conductors. Acknowledgement: The research was supported by the Division of Scientific User Facilities, U. S. Department of Energy.

Kim, Tae Hwan [ORNL; Zhang, Xiaoguang [ORNL; Nicholson, Don M [ORNL; Radhakrishnan, Bala [ORNL; Radhakrishnan, Balasubramaniam [ORNL; Evans III, Boyd Mccutchen [ORNL; Kulkarni, Nagraj S [ORNL; Kenik, Edward A [ORNL; Meyer III, Harry M [ORNL; Li, An-Ping [ORNL

2011-01-01T23:59:59.000Z

322

Droplet sizes, dynamics and deposition in vertical annular flow  

SciTech Connect (OSTI)

The role of droplets in vertical upwards annular flow is investigated, focusing on the droplet size distributions, dynamics, and deposition phenomena. An experimental program was performed based on a new laser optical technique developed in these laboratories and implemented here for annular flow. This permitted the simultaneous measurement of droplet size, axial and radial velocity. The dependence of droplet size distributions on flow conditions is analyzed. The Upper-Log Normal function proves to be a good model for the size distribution. The mechanism controlling the maximum stable drop size was found to result from the interaction of the pressure fluctuations of the turbulent flow of the gas core with the droplet. The average axial droplet velocity showed a weak dependence on gas rates. This can be explained once the droplet size distribution and droplet size-velocity relationship are analyzed simultaneously. The surprising result from the droplet conditional analysis is that larger droplet travel faster than smaller ones. This dependence cannot be explained if the drag curves used do not take into account the high levels of turbulence present in the gas core in annular flow. If these are considered, then interesting new situations of multiplicity and stability of droplet terminal velocities are encountered. Also, the observed size-velocity relationship can be explained. A droplet deposition is formulated based on the particle inertia control. This permitted the calculation of rates of drop deposition directly from the droplet size and velocities data.

Lopes, J C.B.; Dukler, A E

1985-10-01T23:59:59.000Z

323

Grain Sorghum By-Product Feeds for Farm Animals.  

E-Print Network [OSTI]

X3.AJ.N SORGHUM BY-PRODUCT FEEDS FOR FARM ANIMALS FEED FOR LIVESTOCK -. Grain sorghum is the leading feed grain produced in Texas and in the Southwest. Its importance as a feed fc farm animals is generally recognized. Recent developments... in Texas have made available 1 livestock producers and the feed industry a considerab tonnage of sorghum gluten meal and sorghum gluten fee as by-products in sorghum grain processing. The Texas Agricultural Experiment Station conduct( a series...

1951-01-01T23:59:59.000Z

324

A Statistical Analysis of the Sorghum Grain Industry.  

E-Print Network [OSTI]

SUMMARY AND CONCLUSIONS I Sorghum grain has been under price support operations since 1941. The seasonal average price was above the average support price in every year during 1941-52 except in 1949, The seasonal aver- age price was below... the average support price (except in 1955) during 1953-59. This was a result of increased sorghum grain acreage through die verted cotton and wheat acreage and increased yields through hybrid sorghum grain seed which cause supplies to be in excess...

Kincannon, J. A.

1960-01-01T23:59:59.000Z

325

Davis-Greenstein alignment of non-spherical grains  

E-Print Network [OSTI]

Paramagnetic alignment of non-spherical dust grains rotating at thermal velocities is studied. The analytical solution is found for the alignment measure of oblate grains. Perturbative approach is used for solving the problem. It is shown that even the first approximation of the suggested iteration procedure provides the accuracy well within one percent of the expected measure of alignment. The results obtained are applicable both to paramagnetic and to superferromagnetic grains.

A. Lazarian

1995-05-07T23:59:59.000Z

326

Selected Operating Costs for Storage of Sorghum Grain.  

E-Print Network [OSTI]

Selected Operating Costs for Storage Of Sorghum Grain TEXAS A&M UNIVERSITY This is the third of three bulletins reporting the results of a study of sorghum grain storage and handling practices in Texas. The first dealt with marketing and on...-farm storage; the second with com- mercial storage and handling practices. This bulletin reports the results of a study of the costs of com- mercial grain handling practices. Three areas representing a cross section of physical and economic conditions...

Bonnen, C. A. (Clarence Alfred); Cunningham, William C.

1964-01-01T23:59:59.000Z

327

Grain growth and phase stability of nanocrystalline cubic zirconia...  

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

of nanocrystalline cubic zirconia under ion irradiation. Abstract: Grain growth, oxygen stoichiometry and phase stability of nanostructurally-stabilized zirconia (NSZ) in...

328

General Schema for [001] Tilt Grain Boundaries in Dense Packing...  

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

as showing the frustration of symmetry caused by the incorporation of point defects (vacancies and impurities). This general model for grain boundary structures can, in principle,...

329

New Process for Grain Refinement of Aluminum. Final Report  

SciTech Connect (OSTI)

A new method of grain refining aluminum involving in-situ formation of boride nuclei in molten aluminum just prior to casting has been developed in the subject DOE program over the last thirty months by a team consisting of JDC, Inc., Alcoa Technical Center, GRAS, Inc., Touchstone Labs, and GKS Engineering Services. The Manufacturing process to make boron trichloride for grain refining is much simpler than preparing conventional grain refiners, with attendant environmental, capital, and energy savings. The manufacture of boride grain refining nuclei using the fy-Gem process avoids clusters, salt and oxide inclusions that cause quality problems in aluminum today.

Dr. Joseph A. Megy

2000-09-22T23:59:59.000Z

330

Microstructure and Strengthening Mechanisms in an Ultrafine Grained Al-Mg-Sc Alloy Produced by Powder Metallurgy  

SciTech Connect (OSTI)

Additions of Sc to an Al-Mg matrix were investigated, paying particular attention to the influence of Al3Sc precipitates and other dispersoids, as well as grain size, on mechanical behavior. Prior studies have shown that Sc significantly increases the strength of coarse-grained Al-Mg alloys. Prompted by these findings, we hypothesized that it would be of fundamental and technological interest to study the behavior of Sc additions to an ultrafine-grained (UFG) microstructure (e.g., 100s nm). Accordingly, we investigated the microstructural evolution and mechanical behavior of a cryomilled ultrafine grained Al-5Mg-0.4Sc (wt pct) and compared the results to those of an equivalent fine-grained material (FG) produced by powder metallurgy. Experimental materials were consolidated by hot isostatic pressing (HIPing) followed by extrusion or dual mode dynamic forging. Under identical processing conditions, UFG materials generate large Al3Sc precipitates with an average diameter of 154 nm and spaced approximately 1 to 3 m apart, while precipitates in the FG materials have a diameter of 24 nm and are spaced 50 to 200 nm apart. The strengthening mechanisms are calculated for all materials and it is determined that the greatest strengthening contributions for the UFG and FG materials are Mg-O/N dispersion strengthening and precipitate strengthening, respectively.

Tammy J. Harrell; Troy D. Topping; Haiming Wen; Tao Hu; JULIE M. SCHOENUNG; ENRIQUE J. LAVERNIA

2014-12-01T23:59:59.000Z

331

Stochastic thermodynamics of fluctuating density fields: Non-equilibrium free energy differences under coarse-graining  

SciTech Connect (OSTI)

We discuss the stochastic thermodynamics of systems that are described by a time-dependent density field, for example, simple liquids and colloidal suspensions. For a time-dependent change of external parameters, we show that the Jarzynski relation connecting work with the change of free energy holds if the time evolution of the density follows the Kawasaki-Dean equation. Specifically, we study the work distributions for the compression and expansion of a two-dimensional colloidal model suspension implementing a practical coarse-graining scheme of the microscopic particle positions. We demonstrate that even if coarse-grained dynamics and density functional do not match, the fluctuation relations for the work still hold albeit for a different, apparent, change of free energy.

Leonard, T.; Lander, B.; Seifert, U. [II. Institut fr Theoretische Physik, Universitt Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany)] [II. Institut fr Theoretische Physik, Universitt Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany); Speck, T. [Institut fr Theoretische Physik II, Heinrich-Heine-Universitt Dsseldorf, Universittsstrae 1, 40225 Dsseldorf (Germany)] [Institut fr Theoretische Physik II, Heinrich-Heine-Universitt Dsseldorf, Universittsstrae 1, 40225 Dsseldorf (Germany)

2013-11-28T23:59:59.000Z

332

agglomerates sizes approach: Topics by E-print Network  

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

Lorenzo Isella; Yannis Drossinos 2010-04-26 52 A fractal-based approach to lake size-distributions David A. Seekell,1 Environmental Sciences and Ecology Websites Summary:...

333

Control of pore size in epoxy systems.  

SciTech Connect (OSTI)

Both conventional and combinatorial approaches were used to study the pore formation process in epoxy based polymer systems. Sandia National Laboratories conducted the initial work and collaborated with North Dakota State University (NDSU) using a combinatorial research approach to produce a library of novel monomers and crosslinkers capable of forming porous polymers. The library was screened to determine the physical factors that control porosity, such as porogen loading, polymer-porogen interactions, and polymer crosslink density. We have identified the physical and chemical factors that control the average porosity, pore size, and pore size distribution within epoxy based systems.

Sawyer, Patricia Sue; Lenhart, Joseph Ludlow (North Dakota State University, Fargo, ND); Lee, Elizabeth (North Dakota State University, Fargo, ND); Kallam, Alekhya (North Dakota State University, Fargo, ND); Majumdar, Partha (North Dakota State University, Fargo, ND); Dirk, Shawn M.; Gubbins, Nathan; Chisholm, Bret J. (North Dakota State University, Fargo, ND); Celina, Mathias Christopher; Bahr, James (North Dakota State University, Fargo, ND); Klein, Robert J.

2009-01-01T23:59:59.000Z

334

Mono-textured nanocrystalline thin films with pronounced stress-gradients: On the role of grain boundaries in the stress evolution  

SciTech Connect (OSTI)

The origins of residual stress gradients in nanocrystalline thin films, especially the role of grain size and texture gradients, are still not fully understood. In this work, the stress evolution in exemplary nanocrystalline TiN thin films with one and two fiber texture components as well as in homogeneous amorphous SiO{sub x} films is analyzed using wafer curvature as well as laboratory and synchrotron cross-sectional nanobeam X-ray diffraction techniques. The stress evolution across the film thickness is attributed to the evolutionary nature of microstructural development at the individual growth stages. While the effect of the smooth crystallographic texture changes during growth is only of minor importance, as this does not significantly affect the dominant stress formation mechanisms, the change in the grain size accompanied by a change of the volume fraction of grain boundaries plays a decisive role in the stress development across the film thickness. This is demonstrated on the monotextured thin films, where the residual stresses scale with the apparent grain size. These findings are validated also by the investigations of stress profiles in homogeneous amorphous SiO{sub x} films exhibiting no grain boundaries.

Daniel, R., E-mail: Rostislav.Daniel@unileoben.ac.at; Mitterer, C. [Department of Physical Metallurgy and Materials Testing, Montanuniversitt Leoben, Franz-Josef-Strasse 18, 8700 Leoben (Austria); Jger, E.; Sartory, B. [Materials Center Leoben Forschung GmbH, Leoben (Austria); Todt, J.; Keckes, J. [Department of Materials Physics, Montanuniversitt Leoben and Erich Schmid Institute for Materials Science, Austrian Academy of Sciences, Leoben (Austria)

2014-05-28T23:59:59.000Z

335

Size separation in vibrated granular matter  

E-Print Network [OSTI]

We review recent developments in size separation in vibrated granular materials. Motivated by a need in industry to efficiently handle granular materials and a desire to make fundamental advances in non-equilibrium physics, experimental and theoretical investigations have shown size separation to be a complex phenomena. Large particles in a vibrated granular system invariably rise to the top. However, they may also sink to the bottom, or show other patterns depending on subtle variations in physical conditions. While size ratio is a dominant factor, particle specific properties such as density, inelasticity and friction can play an important role. The nature of the energy input, boundary conditions and interstitial air have been also shown to be significant factors in determining spatial distributions. The presence of convection can enhance mixing or lead to size separation. Experimental techniques including direct visualization and magnetic resonance imaging are being used to investigate these properties. Molecular dynamics and Monte Carlo simulation techniques have been developed to probe size separation. Analytical methods such as kinetic theory are being used to study the interplay between particle size and density in the vibro-fluidized regime, and geometric models have been proposed to describe size separation for deep beds. Besides discussing these studies, we will also review the impact of inelastic collision and friction on the density and velocity distributions to gain a deeper appreciation of the non-equilibrium nature of the system. While a substantial number of studies have been accomplished, considerable work is still required to achieve a firm description of the phenomena.

A. Kudrolli

2004-02-06T23:59:59.000Z

336

The effects of grain moisture content and grain temperature on the penetration of hydrogen cyanide  

E-Print Network [OSTI]

to control insect infestations in stored products for many years. Hydrogen cyanide i. s one of the most important fumigants in use today. Unfortunately, an insuffi. cient knowledge of its behavior has cost the fumigator and the storage opera- tor much...THE EFFECTS QF CRAIN MOISTURE CONTENT AND GRAIN TEMiPERATURE ON THE &NETRATION OF HYDROGEN CYANIDE A Thesis SIDNEY EDMUND KUNZ Submitted to the Graduate School of ths Agricultural and Mechanical College of Texas in partial fulfillment...

Kunz, Sidney E

2012-06-07T23:59:59.000Z

337

Ultrasonic Phased Array Sound Field Mapping Through Large-Bore Coarse Grained Cast Austenitic Stainless Steel (CASS) Piping Materials  

SciTech Connect (OSTI)

A sound field beam mapping exercise was conducted to further understand the effects of coarse grained microstructures found in CASS materials on phased array ultrasonic wave propagation. Laboratory measurements were made on three CASS specimens with different microstructures; the specimens were polished and etched to reveal measurable grain sizes, shapes and orientations. Three longitudinal, phased array probes were fixed on a specimen's outside diameter with the sound field directed toward one end (face) of the pipe segment over a fixed range of angles. A point receiver was raster scanned over the surface of the specimen face generating a sound field image. A slice of CASS material was then removed from the specimen end and the beam mapping exercise repeated. The sound fields acquired were analyzed for spot size, coherency, and beam redirection. Analyses were conducted between the resulting sound fields and the microstructural characteristics of each specimen.

Cinson, Anthony D.; Crawford, Susan L.; Prowant, Matthew S.; Diaz, Aaron A.; Hathaway, John E.; Anderson, Michael T.

2012-04-16T23:59:59.000Z

338

Down-sizing Forever  

E-Print Network [OSTI]

Evidence for cosmic down-sizing has been growing over the last decade. It is now clear that the major star-forming epoch for the largest galaxies occurred earlier than for smaller galaxies. This not only runs counter to the popular hierarchical clustering picture, but points to an even more radical revision of our ideas of the evolution of cosmological structure. Galaxies do not form at all.

Douglas Scott; Ali Frolop

2008-03-31T23:59:59.000Z

339

Display Size Wireless LAN  

E-Print Network [OSTI]

.) - Security sofware ­ESET Smart Security. No Reuse PC with English OS for this time. PC PC Code Image Brand PC PC Code Image Brand Model F008 Panasonic CF-W2 Pentium733 M 1.10GHz 256MB 40GB 12.1 inch 1.0kg System Memory HDD Display Size Weight OS Accessory LAN Wireless LAN Remarks PC PC Code Image Brand

Katsumoto, Shingo

340

ARM - Measurement - Cloud size  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Related InformationAciddroplet size ARM Dataicesizesize ARM Data

Note: This page contains sample records for the topic "grain 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

ARM - Measurement - Hydrometeor size  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Related InformationAciddroplet sizeGeometry ARMphase ARM

342

Grain Growth in Niobium for Superconducting Radio Frequency Cavities  

E-Print Network [OSTI]

GRAIN GROWTH IN NIOBIUM FOR SUPERCONDUCTING RADIO FREQUENCY CAVITIES Major: Mechanical Engineering April 2009 Submitted to the Office of Undergraduate Research Texas A&M University in partial fulfillment... of the requirements for the designation as UNDERGRADUATE RESEARCH SCHOLAR A Senior Scholars Thesis by Joshua A. Vernon GRAIN GROWTH IN NIOBIUM FOR SUPERCONDUCTING RADIO FREQUENCY CAVITIES Approved by: Research Advisor: K. T. Hartwig...

Vernon, Joshua A.

2009-06-09T23:59:59.000Z

343

Samples of Stars Beyond the Solar System: Silicate Grains in  

E-Print Network [OSTI]

Samples of Stars Beyond the Solar System: Silicate Grains in Interplanetary Dust Scott Messenger,1 circumstellar silicate grains within interplanetary dust par- ticles (IDPs). Their extrasolar origins are amorphous silicate "GEMS" (glass with embedded metal and sulfides), which is consistent with astronomical

344

Managing Fusarium Head Blight in Virginia Small Grains  

E-Print Network [OSTI]

Breeder, Dept. of Crop and Soil Environmental Sciences, Virginia Tech. cgriffey@vt.edu C.J. LIN Vice@vt.edu WADE THOMASON Extension Grains Specialist, Dept. of Crop and Soil Environmental Sciences, Virginia TechManaging Fusarium Head Blight in Virginia Small Grains MELISSA KELLER Graduate Student, Dept

Liskiewicz, Maciej

345

Fabrication of fine-grain tantalum diffusion barrier tube for Nb{sub 3}Sn conductors  

SciTech Connect (OSTI)

Diffusion barriers used in Nb{sub 3}Sn wire are often fabricated by wrapping Ta sheet into a tube with an overlap seam. A common result of such practice is non-uniform deformation in the Ta sheet as it thins by wire drawing because of non-uniform grain size and texture in the original Ta sheet. Seamless Ta tube with a fine-grain and uniform microstructure would be much better for the diffusion barrier application, but such material is expensive and difficult to manufacture. This report presents results on a new fabrication strategy for Ta tube that shows promise for manufacture of less costly tube with an improved microstructure. The fabrication method begins with seam-welded tube but gives a fine-grain uniform microstructure with little difference between the longitudinal seam weld region and the parent metal after post-weld processing. Severe plastic deformation processing (SPD) applied by area reduction extrusion and tube equal channel angular extrusion (tECAE) are used to refine and homogenize the microstructure. Microstructure and mechanical property results are presented for Ta tubes fabricated by this new processing strategy.

Hartwig, K. T.; Balachandran, S.; Mezyenski, R.; Seymour, N. [Department of Mechanical Engineering, Texas A and M University, TX 77843 (United States); Robinson, J.; Barber, R. E. [Shear Form Inc, 207 Dellwood St, Bryan 77801 (United States)

2014-01-27T23:59:59.000Z

346

Synthesis and characterization of large-grain solid-phase crystallized polycrystalline silicon thin films  

SciTech Connect (OSTI)

n-type polycrystalline silicon (poly-Si) films with very large grains, exceeding 30??m in width, and with high Hall mobility of about 71.5?cm{sup 2}/V s are successfully prepared by the solid-phase crystallization technique on glass through the control of the PH{sub 3} (2% in H{sub 2})/SiH{sub 4} gas flow ratio. The effect of this gas flow ratio on the electronic and structural quality of the n-type poly-Si thin film is systematically investigated using Hall effect measurements, Raman microscopy, and electron backscatter diffraction (EBSD), respectively. The poly-Si grains are found to be randomly oriented, whereby the average area weighted grain size is found to increase from 4.3 to 18??m with increase of the PH{sub 3} (2% in H{sub 2})/SiH{sub 4} gas flow ratio. The stress in the poly-Si thin films is found to increase above 900?MPa when the PH{sub 3} (2% in H{sub 2})/SiH{sub 4} gas flow ratio is increased from 0.025 to 0.45. Finally, high-resolution transmission electron microscopy, high angle annular dark field-scanning tunneling microscopy, and EBSD are used to identify the defects and dislocations caused by the stress in the fabricated poly-Si films.

Kumar, Avishek, E-mail: avishek.kumar@nus.edu.sg, E-mail: dalapatig@imre.a-star.edu.sg [Solar Energy Research Institute of Singapore, National University of Singapore, 7 Engineering Drive 1, Block E3A, #06-01, Singapore 117574 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore); Law, Felix; Widenborg, Per I. [Solar Energy Research Institute of Singapore, National University of Singapore, 7 Engineering Drive 1, Block E3A, #06-01, Singapore 117574 (Singapore); Dalapati, Goutam K., E-mail: avishek.kumar@nus.edu.sg, E-mail: dalapatig@imre.a-star.edu.sg; Subramanian, Gomathy S.; Tan, Hui R. [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore); Aberle, Armin G. [Solar Energy Research Institute of Singapore, National University of Singapore, 7 Engineering Drive 1, Block E3A, #06-01, Singapore 117574 and Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore)

2014-11-01T23:59:59.000Z

347

Linking Grain Boundary Microstructure to Stress Corrosion Cracking of Cold Rolled Alloy 690 in PWR Primary Water  

SciTech Connect (OSTI)

Grain boundary microstructures and microchemistries are examined in cold-rolled alloy 690 tubing and plate materials and comparisons are made to intergranular stress corrosion cracking (IGSCC) behavior in PWR primary water. Chromium carbide precipitation is found to be a key aspect for materials in both the mill annealed and thermally treated conditions. Cold rolling to high levels of reduction was discovered to produce small IG voids and cracked carbides in alloys with a high density of grain boundary carbides. The degree of permanent grain boundary damage from cold rolling was found to depend directly on the initial IG carbide distribution. For the same degree of cold rolling, alloys with few IG precipitates exhibited much less permanent damage. Although this difference in grain boundary damage appears to correlate with measured SCC growth rates, crack tip examinations reveal that cracked carbides appeared to blunt propagation of IGSCC cracks in many cases. Preliminary results suggest that the localized grain boundary strains and stresses produced during cold rolling promote IGSCC susceptibility and not the cracked carbides and voids.

Bruemmer, Stephen M.; Olszta, Matthew J.; Toloczko, Mychailo B.; Thomas, Larry E.

2012-10-01T23:59:59.000Z

348

Sample sizes for confidence limits for reliability.  

SciTech Connect (OSTI)

We recently performed an evaluation of the implications of a reduced stockpile of nuclear weapons for surveillance to support estimates of reliability. We found that one technique developed at Sandia National Laboratories (SNL) under-estimates the required sample size for systems-level testing. For a large population the discrepancy is not important, but for a small population it is important. We found that another technique used by SNL provides the correct required sample size. For systems-level testing of nuclear weapons, samples are selected without replacement, and the hypergeometric probability distribution applies. Both of the SNL techniques focus on samples without defects from sampling without replacement. We generalized the second SNL technique to cases with defects in the sample. We created a computer program in Mathematica to automate the calculation of confidence for reliability. We also evaluated sampling with replacement where the binomial probability distribution applies.

Darby, John L.

2010-02-01T23:59:59.000Z

349

Taming Density Functional Theory by Coarse-Graining  

E-Print Network [OSTI]

The standard (``fine-grained'') interpretation of quantum density functional theory, in which densities are specified with infinitely-fine spatial resolution, is mathematically unruly. Here, a coarse-grained version of DFT, featuring limited spatial resolution, and its relation to the fine-grained theory in the $L^1\\cap L^3$ formulation of Lieb, is studied, with the object of showing it to be not only mathematically well-behaved, but consonant with the spirit of DFT, practically (computationally) adequate and sufficiently close to the standard interpretation as to accurately reflect its non-pathological properties. The coarse-grained interpretation is shown to be a good model of formal DFT in the sense that: all densities are (ensemble)-V-representable; the intrinsic energy functional $F$ is a continuous function of the density and the representing external potential is the (directional) functional derivative of the intrinsic energy. Also, the representing potential $v[\\rho]$ is quasi-continuous, in that $v[\\rho]\\rho$ is continuous as a function of $\\rho$. The limit of coarse-graining scale going to zero is studied to see if convergence to the non-pathological aspects of the fine-grained theory is adequate to justify regarding coarse-graining as a good approximation. Suitable limiting behaviors or intrinsic energy, densities and representing potentials are found. Intrinsic energy converges monotonically, coarse-grained densities converge uniformly strongly to their low-intrinsic-energy fine-grainings, and $L^{3/2}+L^\\infty$ representability of a density is equivalent to the existence of a convergent sequence of coarse-grained potential/ground-state density pairs.

Paul E. Lammert

2010-08-10T23:59:59.000Z

350

Optimum Size of Nanorods for Heating Application  

E-Print Network [OSTI]

Magnetic nanoparticles (MNP's) have become increasingly important in heating applications such as hyperthermia treatment of cancer due to their ability to release heat when a remote external alternating magnetic field is applied. It has been shown that the heating capability of such particles varies significantly with the size of particles used. In this paper, we theoretically evaluate the heating capability of rod-shaped MNP's and identify conditions under which these particles display highest efficiency. For optimally sized monodisperse particles, the power generated by rod-shaped particles is found to be equal to that generated by spherical particles. However, for particles which have a dispersion in size, rod-shaped particles are found to be more effective in heating as a result of the greater spread in the power density distribution curve. Additionally, for rod-shaped particles, a dispersion in the radius of the particle contributes more to the reduction in loss power when compared to a dispersion in the...

Seshadri, Gowrishankar; Mehra, Anurag

2013-01-01T23:59:59.000Z

351

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

352

Concentrations and Size Distributions of Particulate Matter Emissions...  

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

& Organic Carbon - PAHs and n-PAHs - Elemental Compounds - Ionic Species - Carbonyls - Dioxins and Furans - Bioassays Sampling System Diluted Exhaust 1 0 11 6 7 8 a 8 b 3 4 BXDX...

353

The geographic distribution of mammal body size in Europe  

E-Print Network [OSTI]

Nacionales, Madrid. Peltier, W. (1993) Time dependentlast glacial maximum (Peltier, 1993). This variable measures

Rodriguez, M A; Lopez-Sanudo, I L; Hawkins, Bradford A.

2006-01-01T23:59:59.000Z

354

The geographic distribution of mammal body size in Europe  

E-Print Network [OSTI]

cell age), estim- ated by mapped changes in ice coverage at 1-Kyr intervals since the last glacial maximum (Peltier,

Rodriguez, M A; Lopez-Sanudo, I L; Hawkins, Bradford A.

2006-01-01T23:59:59.000Z

355

aerosol size distributions: Topics by E-print Network  

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

for Davos, Mauna Loa and Izana Physics (arXiv) Summary: Atmospheric flows exhibit fractal fluctuations and inverse power law form for power spectra indicating an eddy...

356

aerosol size distribution: Topics by E-print Network  

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

for Davos, Mauna Loa and Izana Physics (arXiv) Summary: Atmospheric flows exhibit fractal fluctuations and inverse power law form for power spectra indicating an eddy...

357

Concentrations and Size Distributions of Particulate Matter Emissions from  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-Up fromDepartmentTieCelebrate Earth Codestheatfor Optimized9 *Concentrating Solar

358

Evolution of droplet size distribution and autoconversion parameterization  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing ZirconiaPolicy and Assistance100 tonusing ARMEvenFlames. |RecentEvolution ofin

359

Raindrop size distributions and associated effective radar reflectivity comparisons /  

E-Print Network [OSTI]

-0. 629869Z6 19. 38 - 8. 59 6. 40 5. o3 0. 0001 0. 0001 0. 0001 0. 0001 F VALUE 184. 66 PR& F 0. 0001 STD DEV 0. 58555116 R-SQUARE 0. 527609 C. V. 41. 2185 LI'ISUBI MEAN 1. 42060192 DF 1 1 1 TYPE IV SS F VALUE 25. 27055111 73... for the detection of severe weather phenomena such as tornadoes, hailstorms, and severe thunderstomns. In addition to storm applications, radar observations, concurrent with di sdrometer determi- nations of raindrop spectra, are important data for cloud physics...

Gosdin, Malcolm Elwood

1982-01-01T23:59:59.000Z

360

Estimating sandstone permeability using network models with pore size distributions  

E-Print Network [OSTI]

in appearance to empirical data. A network model is developed to simulate the pore geometry of a clean, well-sorted sandstone. Pores were modeled as straight capillaries connected in various lattice configurations. Complex lattice configurations produce more... properties and can be closely monitored, allowing for study of their effects on flow in the network lattice. Various parameter variation techniques are introduced in the literature. These techniques induce flow property changes in the model allowing rock...

Mathews, Alan Ronald

1991-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

Irradiation Assisted Grain Boundary Segregation in Steels  

SciTech Connect (OSTI)

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

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

2008-07-01T23:59:59.000Z

362

Usage by Job Size  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered energy consumption by sectorlongUpdates by DianeDemographics UsageUsage by Job Size

363

Grain shape variation and sedimentary processes of the Neogene-Quaternary sediments in Baffin Bay and Labrador Sea  

E-Print Network [OSTI]

fractured and overgrown grains. Fractured grains con- tribute to higher harnionic amplitudes of Fourier grain shape measurement; rounded grains contribute to lower harmonic amplitudes of Fourier grain shape iueasurement. The variation in the average grain... shape harmonic aiuplitudes reflects the variation of the three grain types. This varia. tion of fractured grains anil rounded grains are controlled by different sedinientary dynamics iuid(or) different sediiuent sources. 'The southward-directed flow...

Shan, Yongtang

1989-01-01T23:59:59.000Z

364

Natural geological responses to anthropogenic alterations of the naples bay estuarine system  

E-Print Network [OSTI]

content. Grain size distribution for the grab samples and vibracores was evaluated using a Malvern? Mastersizer 2000 TM (Malvern, UK). The Mastersizer 2000 is a particle size analyzer using laser diffraction to produce a grain size distribution...

Fielder, Bryan Robert

2009-05-15T23:59:59.000Z

365

DUST GRAIN EVOLUTION IN SPATIALLY RESOLVED T TAURI BINARIES  

SciTech Connect (OSTI)

Core-accretion planet formation begins in protoplanetary disks with the growth of small, interstellar medium dust grains into larger particles. The progress of grain growth, which can be quantified using 10 {mu}m silicate spectroscopy, has broad implications for the final products of planet formation. Previous studies have attempted to correlate stellar and disk properties with the 10 {mu}m silicate feature in an effort to determine which stars are efficient at grain growth. Thus far there does not appear to be a dominant correlated parameter. In this paper, we use spatially resolved adaptive optics spectroscopy of nine T Tauri binaries as tight as 0.''25 to determine if basic properties shared between binary stars, such as age, composition, and formation history, have an effect on dust grain evolution. We find with 90%-95% confidence that the silicate feature equivalent widths of binaries are more similar than those of randomly paired single stars, implying that shared properties do play an important role in dust grain evolution. At lower statistical significance, we find with 82% confidence that the secondary has a more prominent silicate emission feature (i.e., smaller grains) than the primary. If confirmed by larger surveys, this would imply that spectral type and/or binarity are important factors in dust grain evolution.

Skemer, Andrew J.; Close, Laird M.; Hinz, Philip M.; Hoffmann, William F.; Males, Jared R. [Steward Observatory, Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Greene, Thomas P. [NASA Ames Research Center, Moffett Field, CA 94035 (United States)

2011-10-10T23:59:59.000Z

366

Aerosol measurements at a high-elevation site: composition, size, and cloud condensation nuclei activity  

E-Print Network [OSTI]

Measurements of cloud condensation nuclei (CCN) concentrations, single particle composition and size distributions at a high-elevation research site from March 2011 are presented.

Friedman, B.

367

Feeding Value of Wet Sorghum Distillers Grains for Growing and Finishing Beef Cattle  

E-Print Network [OSTI]

Feeding Value of Wet Sorghum Distillers Grains for Growing and Finishing Beef Cattle Ethanol, but sorghum grain is commonly either blended with corn before use or used as the sole grain for ethanol

368

Grain boundary and triple junction constraints during martensitic transformation in shape memory alloys  

E-Print Network [OSTI]

We investigate the role of grain constraint upon martensitic transformation through in situ scanning electron microscope tensile experiments on shape memory microwires with a small number of grains and grain junctions. The ...

Ueland, Stian Melhus

369

Profitable Small Grain Production In the Texas Gulf Coast.  

E-Print Network [OSTI]

grains. Oats provides a greater forage yield than wheat but is considerably more sensitive to winter kill. Occasionally all top growth is lost in one abnormaJIy cold period. The forage provided by small grains is quite nutritious, with protein...TDOC Z TA24S.7 8873 NO.1S87 Texas Agricultural Extension Service LIBRARY SEP 2 7 1988 a~ A&M Univers' Profitable Small Grain Production In The Texas Gulf Coast 8-1587 Texas Agricultural Extension Service. Zerle L. Carpenter, Director...

Miller, Travis D.; Livingston, Steve

1987-01-01T23:59:59.000Z

370

Control of johnsongrass in grain sorghum with SD-58525  

E-Print Network [OSTI]

of grain sorghum [Sorghum bicolor (L. ) Noench. ] had little effect on 1ts ability to tolerate SD-58525. Initially the grain sorghum was injured at all stages of' growth but recovered. 6rain yield was reduced by SD-58525 at the 2. 24 and 4. 48 kg.... Effect of SD-58525 on grain sorghum fresh weights when grown under a halide light source and applied at various stages of growth. . . 13 3. Effect of postemergence treatment of SD-58525 on population of weeds 5. 0 cm in height at the time...

Newcomer, Drew Trussell

1982-01-01T23:59:59.000Z

371

Manufacturing process to reduce large grain growth in zirconium alloys  

DOE Patents [OSTI]

It is an object of the present invention to provide a procedure for desensitizing zirconium-based alloys to large grain growth (LGG) during thermal treatment above the recrystallization temperature of the alloy. It is a further object of the present invention to provide a method for treating zirconium-based alloys which have been cold-worked in the range of 2 to 8% strain to reduce large grain growth. It is another object of the present invention to provide a method for fabricating a zirconium alloy clad nuclear fuel element wherein the zirconium clad is resistant to large grain growth.

Rosecrans, P.M.

1984-08-01T23:59:59.000Z

372

Kapitza Resistance of the Grain Boundaries in Ceria  

SciTech Connect (OSTI)

Thermal conductivity is one of the key performance metrics of the nuclear fuels. In electrical insulators, such as most ubiquitous nuclear fuel UO2, thermal transport is due to phonons, or lattice waves. Their propagation is impeded by any lattice defect, such as impurities or vacancies, as well as larger microstructural features: grain boundaries, dislocations and pores/bubbles. Detailed description of the phonons interactions with these features is still lacking. In this work, we elucidate the dependence of the grain boundary thermal resistance, also known as a Kapitza resistance, on the type and misorientation angle of the grain boundary in model system of CeO2.

David Bai; Jian Gan; Aleksandr Chernatynskiy

2014-06-01T23:59:59.000Z

373

Resonance Paramagnetic Relaxation and Alignment of Ultrasmall Grains  

E-Print Network [OSTI]

This paper gives a short summary of a mechanism of the enhanced paramagnetic relaxation that acts on rapidly rotating interstellar grains. We show that the Barnett magnetization that arises from grain rotation ensures that paramagnetic absorption happens at its maximum efficiency, i.e. the conditions for paramagnetic resonance are automatically fulfilled. The differences between the predictions of classical Davis-Greenstein relaxation and the process which we refer to as ``resonance relaxation'' are most pronounced for grains rotating faster than 10 GHz. Microwave polarization is likely to be an impediment for cosmic microwave background studies, but can provide a good tool for studying galactic magnetic field.

Lazarian A

1998-11-03T23:59:59.000Z

374

Coarse-graining DNA for simulations of DNA nanotechnology  

E-Print Network [OSTI]

To simulate long time and length scale processes involving DNA it is necessary to use a coarse-grained description. Here we provide an overview of different approaches to such coarse graining, focussing on those at the nucleotide level that allow the self-assembly processes associated with DNA nanotechnology to be studied. OxDNA, our recently-developed coarse-grained DNA model, is particularly suited to this task, and has opened up this field to systematic study by simulations. We illustrate some of the range of DNA nanotechnology systems to which the model is being applied, as well as the insights it can provide into fundamental biophysical properties of DNA.

Doye, Jonathan P K; Louis, Ard A; Romano, Flavio; Sulc, Petr; Matek, Christian; Snodin, Benedict E K; Rovigatti, Lorenzo; Schreck, John S; Harrison, Ryan M; Smith, William P J

2013-01-01T23:59:59.000Z

375

Competition among different height genotypes of grain sorghum hybrids  

E-Print Network [OSTI]

of differences from check for Temple (test 3), 45 Summary of differences from check for Temple (test 4). 46 vii LIST OF FIGURES Figures Page Deviations of treatments from the mean yield of grain in pounds per acre for the 3x3 hybrids over- all locations... Deviations of treatments from the mean yield of grain in pounds per acre for the 3x4 hybrids over- all locations 18 Deviations of treatments from the mean yield of grain in pounds per acre for the 4x4 hy'bride over- all locations Deviations of treatments...

Miller, Frederick Robert

2012-06-07T23:59:59.000Z

376

Grain growth behavior and high-temperature high-strain-rate tensile ductility of iridium alloy DOP-26  

SciTech Connect (OSTI)

This report summarizes results of studies conducted to date under the Iridium Alloy Characterization and Development subtask of the Radioisotope Power System Materials Production and Technology Program to characterize the properties of the new-process iridium-based DOP-26 alloy used for the Cassini space mission. This alloy was developed at Oak Ridge National Laboratory (ORNL) in the early 1980`s and is currently used by NASA for cladding and post-impact containment of the radioactive fuel in radioisotope thermoelectric generator (RTG) heat sources which provide electric power for interplanetary spacecraft. Included within this report are data generated on grain growth in vacuum or low-pressure oxygen environments; a comparison of grain growth in vacuum of the clad vent set cup material with sheet material; effect of grain size, test temperature, and oxygen exposure on high-temperature high-strain-rate tensile ductility; and grain growth in vacuum and high-temperature high-strain-rate tensile ductility of welded DOP-26. The data for the new-process material is compared to available old-process data.

McKamey, C.G.; Gubbi, A.N.; Lin, Y.; Cohron, J.W.; Lee, E.H.; George, E.P.

1998-04-01T23:59:59.000Z

377

The Composition of Interstellar Grains Toward Zeta Ophiuchi: Constraining the Elemental Budget Near the Diffuse-Dense Cloud Transition  

E-Print Network [OSTI]

We investigate the composition of interstellar grains along the line of sight toward Zeta Ophiuchi, a well-studied environment near the diffuse-dense cloud transition. A spectral decomposition analysis of the solid-state absorbers is performed using archival spectroscopic observations from the Spitzer Space Telescope and Infrared Space Observatory. We find strong evidence for the presence of sub-micron-sized amorphous silicate grains, principally comprised of olivine-like composition, with no convincing evidence of H2O ice mantles. However, tentative evidence for thick H2O ice mantles on large (a ~ 2.8 microns) grains is presented. Solid-state abundances of elemental Mg, Si, Fe, and O are inferred from our analysis and compared to standard reference abundances. We find that nearly all of elemental Mg and Si along the line of sight are present in amorphous silicate grains, while a substantial fraction of elemental Fe resides in compounds other than silicates. Moreover, we find that the total abundance of eleme...

Poteet, Charles A; Draine, Bruce T

2015-01-01T23:59:59.000Z

378

Thermodynamics of microstructure evolution: grain growth Victor L. Berdichevsky  

E-Print Network [OSTI]

Thermodynamics of microstructure evolution: grain growth Victor L. Berdichevsky Mechanical thermodynamic parameters, entropy of microstructure and temperature of microstruc- ture. It was claimed that there is "one more law of thermodynamics": entropy of microstructure must decay in isolated thermodynamic stable

Berdichevsky, Victor

379

Phenological development of grain sorghum as affected by planting date  

E-Print Network [OSTI]

Phenological development of grain sorghum [Sorghum bicolor (L.) Moench] is a direct result of accumulated heat units (growing degree days) from emergence to physiological maturity. This study was conducted in 1994 and 1995 to determine the effect...

Medley, James C.

1998-01-01T23:59:59.000Z

380

Effect of tensile strain on grain connectivity and flux pinning...  

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

tensile strain on grain connectivity and flux pinning in Bi 2 Sr 2 Ca 2 Cu 3 O x tapes D. C. van der Laan and J. W. Ekin National Institute of Standards and Technology, Boulder,...

Note: This page contains sample records for the topic "grain 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

Study of grain compositions in comet Levy 1990XX  

E-Print Network [OSTI]

In the present work, the non-spherical dust grain characteristics of comet Levy 1990XX with different silicate grain compositions (both pyroxene and olivine) are studied using the T-matrix method. Considering amorphous pyroxene grain (Mg$_x$Fe$_{1-x}$SiO$_3$) with $x$ (= 0.4, 0.5, 0.6, 0.7, 0.8, 0.95, 1) and amorphous olivine grain (Mg$_{2y}$Fe$_{2-2y}$SiO$_4$) with $y$ (= 0.4, 0.5) (Dorschner et al. 1995), the observed polarization data of comet Levy1990XX are analyzed using the T-matrix code at $\\lambda$ = 0.485 $\\mu m$.

H. S. Das; R. Bhattacharjee; B. K. Sinha; A. K. Sen

2007-05-22T23:59:59.000Z

382

alignment probing grain: Topics by E-print Network  

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

grains, and hence the elemental abundance, is constrained from the reddening versus hydrogen column density, E(B-V)NH. If we take the solar elemental abundance as a standard...

383

Grain Boundary Structure Effects on Intergranular Stress Corrosion Cracking of  

E-Print Network [OSTI]

Grain Boundary Structure Effects on Intergranular Stress Corrosion Cracking of Alloy X­750 Y. Pan B­of­freedom) and correlations with intergranular stress corrosion cracking observed in Alloy X­750. Orientation imaging

Olson, Tamara

384

Deadlock-free fine-grained thread migration  

E-Print Network [OSTI]

Several recent studies have proposed fine-grained, hardware-level thread migration in multicores as a solution to power, reliability, and memory coherence problems. The need for fast thread migration has been well documented, ...

Cho, Myong Hyon

385

Multiresolution methods for materials modeling via coarse-graining  

E-Print Network [OSTI]

(cont.) time, while obtaining useful information about the thermodynamic behavior of the system. We show how statistical mechanics can be formulated using the wavelet transform as a coarse-graining technique. For small ...

Ismail, Ahmed E. (Ahmed Emad), 1977-

2005-01-01T23:59:59.000Z

386

Thermal conductivity and specific heat of sorghum grain  

E-Print Network [OSTI]

Formation of Test Canister Ice Jacket ~ Sealing Test Canister in Calorimeter. . 43 44 Testing of Samples. Initial Calorimeter Observations. 49 Insertion of Grain Samples into Calorimeter. . . . 50 Final Test Observations Processing of Data. 54... to Contain the Grain Sample 38 for the Determination of Specific Heat 39 12. Top View of Calorimeter. 40 13. Galvanized Iron Cylinder Used to Form the Ice Jacket Around the Test Canister 42 VIII Figures 14. Clamping Device Used to Hold Test Canister...

Miller, Clinton Frank

1963-01-01T23:59:59.000Z

387

Grained composite materials prepared by combustion synthesis under mechanical pressure  

DOE Patents [OSTI]

Dense, finely grained composite materials comprising one or more ceramic phase or phase and one or more metallic and/or intermetallic phase or phases are produced by combustion synthesis. Spherical ceramic grains are homogeneously dispersed within the matrix. Methods are provided, which include the step of applying mechanical pressure during or immediately after ignition, by which the microstructures in the resulting composites can be controllably selected.

Dunmead, Stephen D. (Davis, CA); Holt, Joseph B. (San Jose, CA); Kingman, Donald D. (Danville, CA); Munir, Zuhair A. (Davis, CA)

1990-01-01T23:59:59.000Z

388

Systems simulation of oil additives to grain at terminal elevators  

E-Print Network [OSTI]

SYSTEMS SIMULATION OF OIL ADDITIVES TO GRAIN AT TERMINAL ELEVATORS A Thesis by Kerry James Goforth Submitted to the Graduate College of Texas A8M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May... 1985 Major Subject: Agricultural Engineering SYSTEMS SIMULATION OF OIL ADDITIVES TO GRAIN AT TERMINAL ELEVATORS A Thesis by KERRY J. GOFORTH Approved as to style and content by: Calvin B. Parne 1, Jr. (Chairman of Committee) tto R. Kunze...

Goforth, Kerry James

1985-01-01T23:59:59.000Z

389

The Influence of Particle Size on Infrared Reflectance Spectra  

SciTech Connect (OSTI)

Reflectance spectra of solids are influenced by the absorption coefficient as well as the particle size and morphology. In the infrared, spectral features may be observed as either maxima or minima: in general, the upward-going peaks in the reflectance spectrum result from surface scattering, which are rays that have reflected from the surface without penetration, whereas downward-going peaks result from either absorption or volume scattering, i.e. rays that have penetrated into the sample or refracted into the sample interior and are not reflected. The light signal reflected from solids usually encompasses all these effects which include dependencies on particle size, morphology and sample density. This paper measures the reflectance spectra in the 1.3 16 micron range for various bulk materials that have a combination of strong and weak absorption bands in order to understand the effects on the spectral features as a function of the mean grain size of the sample. The bulk materials were ground with a mortar and pestle and then sieved to separate the samples into various size fractions: 0-45, 45-90, 90-180, 180-250, 250-500, and >500 microns. The directional-hemispherical spectra were recorded using a Fourier transform infrared spectrometer equipped with an integrating sphere to measure the reflectance for all of the particle-size fractions. We have studied both organic and inorganic materials, but this paper focuses on inorganic salts, NaNO3 in particular. Our studies clearly show that particle size has an enormous influence on the measured reflectance spectra for bulk materials and that successful identification requires sufficient representative reflectance data so as to include the particle size(s) of interest. Origins of the effects are discussed.

Myers, Tanya L.; Brauer, Carolyn S.; Su, Yin-Fong; Blake, Thomas A.; Johnson, Timothy J.; Richardson, Robert L.

2014-06-13T23:59:59.000Z

390

Strategic Petroleum Reserve: Analysis of size options  

SciTech Connect (OSTI)

This report presents the results of the deliberations of the interagency group formed to study the costs and benefits of expanding the size of the SPR. The study concentrated on severe oil supply disruptions involving sharp reductions in world oil production that were 2 to 4 times larger than the largest 1970s interruption. The disruption sizes and estimated probability of occurrence of these scenarios were supplied by the CIA. The most critical part of the CIA's analysis was the assessment of likelihood of these cases occurring. The CIA approached the likelihood problem by combining an examination of past oil supply disruptions with qualitative analysis of important oil market and regional trends. The study group then used statistical techniques and probability distributions to synthesize the historical data with CIA evaluations of as yet unobserved events. The SPR size study assumed direct purchases of SPR oil and did not assume the use of alternative financing mechanisms. Members of the working group with foreign policy and national security responsibilities provided an in-depth review of strategic considerations affecting SPR size. A number of prior studies, some classified, have addressed the strategic importance and insurance value of the SPR to the US and its allies. The results of these studies have also been incorporated in the current effort. 10 refs., 5 figs.

Not Available

1990-02-01T23:59:59.000Z

391

Distributed Generation  

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

come a long way in addressing interconnection standards for distributed generation, utilities have largely overlooked the untapped potential of these resources. Under certain...

392

The Effect of High Temperature Annealing on the Grain Characteristics of a Thin Chemical Vapor Deposition Silicon Carbide Layer.  

SciTech Connect (OSTI)

The unique combination of thermo-mechanical and physiochemical properties of silicon carbide (SiC) provides interest and opportunity for its use in nuclear applications. One of the applications of SiC is as a very thin layer in the TRi-ISOtropic (TRISO) coated fuel particles for high temperature gas reactors (HTGRs). This SiC layer, produced by chemical vapor deposition (CVD), is designed to withstand the pressures of fission and transmutation product gases in a high temperature, radiation environment. Various researchers have demonstrated that macroscopic properties can be affected by changes in the distribution of grain boundary plane orientations and misorientations [1 - 3]. Additionally, various researchers have attributed the release behavior of Ag through the SiC layer as a grain boundary diffusion phenomenon [4 - 6]; further highlighting the importance of understanding the actual grain characteristics of the SiC layer. Both historic HTGR fission product release studies and recent experiments at Idaho National Laboratory (INL) [7] have shown that the release of Ag-110m is strongly temperature dependent. Although the maximum normal operating fuel temperature of a HTGR design is in the range of 1000-1250C, the temperature may reach 1600C under postulated accident conditions. The aim of this specific study is therefore to determine the magnitude of temperature dependence on SiC grain characteristics, expanding upon initial studies by Van Rooyen et al, [8; 9].

Isabella J van Rooyen; Philippus M van Rooyen; Mary Lou Dunzik-Gougar

2013-08-01T23:59:59.000Z

393

Measuring the Influence of Grain-Boundary Misorientation on Thermal Groove Geometry in Ceramic Polycrystals  

E-Print Network [OSTI]

Measuring the Influence of Grain-Boundary Misorientation on Thermal Groove Geometry in Ceramic. The width and depth of the thermal grooves formed by these same grain bound- aries were also measured of the grain-boundary misorientation and thermal groove ge- ometry leads to the observation that grain

Rohrer, Gregory S.

394

Wide size range fast integrated mobility spectrometer  

DOE Patents [OSTI]

A mobility spectrometer to measure a nanometer particle size distribution is disclosed. The mobility spectrometer includes a conduit and a detector. The conduit is configured to receive and provide fluid communication of a fluid stream having a charged nanometer particle mixture. The conduit includes a separator section configured to generate an electrical field of two dimensions transverse to a dimension associated with the flow of the charged nanometer particle mixture through the separator section to spatially separate charged nanometer particles of the charged nanometer particle mixture in said two dimensions. The detector is disposed downstream of the conduit to detect concentration and position of the spatially-separated nanometer particles.

Wang, Jian

2013-10-29T23:59:59.000Z

395

Size Reduction and Densification of Lignocellulosic Biomass Feedstock for Biopower, Bioproducts, and  

E-Print Network [OSTI]

Size Reduction and Densification of Lignocellulosic Biomass Feedstock for Biopower, Bioproducts reduction and densification of lignocellulosic biomass feedstock play a crucial role in the preprocessing and supply of biomass. Size reduction is an operation where the size distribution of biomass particles

396

Interactions of mobile helium clusters with surfaces and grain boundaries of plasma-exposed tungsten  

SciTech Connect (OSTI)

We report results of atomistic computations for the interactions of small mobile helium clusters (He{sub n}) with free surfaces and grain boundaries (GBs) in tungsten toward development of continuum drift-diffusion-reaction models for the dynamics of mobile helium clusters in plasma-exposed tungsten. Molecular-statics (MS) simulations based on reliable many-body interatomic potentials are carried out for He{sub n} (1???n???7) clusters near sinks to obtain the potential energy profiles of the He{sub n} clusters as a function of the clusters' center-of-mass distance from a sink. Sinks investigated include surfaces, GBs, and regions in the vicinity of junctions where GBs intersect free surfaces. Elastic interaction potentials based on elastic inclusion theory provide an excellent description of the MS results for the cluster-sink interactions. The key parameter in the elastic models is the sink segregation strength, which is found to increase with increasing cluster size. Such cluster-sink interactions are responsible for the migration of small helium clusters by drift and for helium segregation on surfaces and grain boundaries in tungsten. Such helium segregation on sinks is observed in large-scale molecular-dynamics simulations of helium aggregation in model polycrystalline tungsten at 933?K upon helium implantation.

Hu, Lin; Maroudas, Dimitrios, E-mail: maroudas@ecs.umass.edu [Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01003-9303 (United States); Hammond, Karl D.; Wirth, Brian D. [Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States)

2014-05-07T23:59:59.000Z

397

Study of Etching Pits in a Large-grain Single Cell Bulk Niobium Cavity  

SciTech Connect (OSTI)

Performance of SRF cavities are limited by non-linear localized effects. The variation of local material characters between "hot" and "cold" spots is thus of intense interest. Such locations were identified in a BCP-etched large-grain single-cell cavity and removed for examination by high resolution electron microscopy (SEM), electron-back scattering diffraction microscopy (EBSD), optical microscopy, and 3D profilometry. Pits with clearly discernable crystal facets were observed in both "hotspot" and "coldspot" specimens. The pits were found in-grain, at bi-crystal boundaries, and on tri-crystal junctions. They are interpreted as etch pits induced by surface crystal defects (e.g. dislocations). All "coldspots" examined had qualitatively low density of etching pits or very shallow tri-crystal boundary junction. EBSD revealed crystal structure surrounding the pits via crystal phase orientation mapping, while 3D profilometry gave information on the depth and size of the pits. In addition, a survey of the samples by energy dispersive X-ray analysis (EDX) did not show any significant contamination of the samples surface.

Zhao, Xin [William and Mary College; Ciovati, Gianluigi [JLAB; Reece, Charles E. [JLAB; Wu, Andy T. [JLAB

2009-11-01T23:59:59.000Z

398

Effect of build geometry on the ?-grain structure and texture in additive manufacture of Ti-6Al-4V by selective electron beam melting  

SciTech Connect (OSTI)

With titanium alloys, the solidification conditions in Additive Manufacturing (AM) frequently lead to coarse columnar ?-grain structures. The effect of geometry on the variability in the grain structure and texture, seen in Ti-6Al-4V alloy components produced by Selective Electron Beam Melting (SEBM), has been investigated. Reconstruction of the primary ?-phase, from ?-phase EBSD data, has confirmed that in bulk sections where in-fill hatching is employed growth selection favours columnar grains aligned with an <001> {sub ?} direction normal to the deposited powder layers; this results in a coarse ?-grain structure with a strong < 001 > {sub ?} fibre texture (up 8 x random) that can oscillate between a near random distribution around the fibre axis and cube reinforcement with build height. It is proposed that this behaviour is related to the highly elongated melt pool and the raster directions alternating between two orthogonal directions every layer, which on average favours grains with cube alignment. In contrast, the outline, or contour, pass produces a distinctly different grain structure and texture resulting in a skin layer on wall surfaces, where nucleation occurs off the surrounding powder and growth follows the curved surface of the melt pool. This structure becomes increasingly important in thin sections. Local heterogeneities have also been found within different section transitions, resulting from the growth of skin grain structures into thicker sections. Texture simulations have shown that the far weaker ?-texture (? 3 x random), seen in the final product, arises from transformation on cooling occurring with a near random distribution of ?-plates across the 12 variants possible from the Burgers relationship. - Highlights: Distinctly different skin and bulk structures are produced by the contour and hatching passes. Bulk sections contain coarse ?-grains with a < 001 > fibre texture in the build direction. This oscillates between a random distribution around the axis and cube reinforcement. In the skin layer nucleation occurs off the surrounding powder bed and growth occurs inwards. Simulations show that a weak ?-texture results from a random distribution across habit variants.

Antonysamy, A.A., E-mail: alphons.antonysamy@GKNAerospace.com [Additive Manufacturing Centre, GKN Aerospace, P.O. Box 500, Golf Course Lane, Filton, BS34 9 AU (United Kingdom); Meyer, J., E-mail: jonathan.meyer@eads.com [EADS Innovation Works, 20A1 Building, Golf Course Lane, Filton, Bristol, BS997AR (United Kingdom); Prangnell, P.B., E-mail: philip.prangnell@manchester.ac.uk [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom)

2013-10-15T23:59:59.000Z

399

Impulsive Spot Heating and Thermal Explosion of Interstellar Grains Revisited  

E-Print Network [OSTI]

The problem of impulsive heating of dust grains in cold, dense interstellar clouds is revisited theoretically, with the aim to better understand leading mechanisms of the explosive desorption of icy mantles. It is rigorously shown that if the heating of a reactive medium occurs within a sufficiently localized spot (e.g., heating of mantles by cosmic rays), then the subsequent thermal evolution is characterized by a single dimensionless number $\\lambda$. This number identifies a bifurcation between two distinct regimes: When $\\lambda$ exceeds a critical value (threshold), the heat equation exhibits the explosive solution, i.e., the thermal (chemical) explosion is triggered. Otherwise, thermal diffusion causes the deposited heat to spread over the entire grain -- this regime is commonly known as the whole-grain heating. The theory allows us to find a critical combination of the physical parameters that govern the explosion of icy mantles due to impulsive spot heating. In particular, the calculations suggest tha...

Ivlev, A V; Vasyunin, A; Caselli, P

2015-01-01T23:59:59.000Z

400

PROTOPLANETARY DISK STRUCTURE WITH GRAIN EVOLUTION: THE ANDES MODEL  

SciTech Connect (OSTI)

We present a self-consistent model of a protoplanetary disk: 'ANDES' ('AccretioN disk with Dust Evolution and Sedimentation'). ANDES is based on a flexible and extendable modular structure that includes (1) a 1+1D frequency-dependent continuum radiative transfer module, (2) a module to calculate the chemical evolution using an extended gas-grain network with UV/X-ray-driven processes and surface reactions, (3) a module to calculate the gas thermal energy balance, and (4) a 1+1D module that simulates dust grain evolution. For the first time, grain evolution and time-dependent molecular chemistry are included in a protoplanetary disk model. We find that grain growth and sedimentation of large grains onto the disk midplane lead to a dust-depleted atmosphere. Consequently, dust and gas temperatures become higher in the inner disk (R {approx}< 50 AU) and lower in the outer disk (R {approx}> 50 AU), in comparison with the disk model with pristine dust. The response of disk chemical structure to the dust growth and sedimentation is twofold. First, due to higher transparency a partly UV-shielded molecular layer is shifted closer to the dense midplane. Second, the presence of big grains in the disk midplane delays the freeze-out of volatile gas-phase species such as CO there, while in adjacent upper layers the depletion is still effective. Molecular concentrations and thus column densities of many species are enhanced in the disk model with dust evolution, e.g., CO{sub 2}, NH{sub 2}CN, HNO, H{sub 2}O, HCOOH, HCN, and CO. We also show that time-dependent chemistry is important for a proper description of gas thermal balance.

Akimkin, V.; Wiebe, D.; Pavlyuchenkov, Ya. [Institute of Astronomy of the RAS, Pyatnitskaya str. 48, Moscow (Russian Federation)] [Institute of Astronomy of the RAS, Pyatnitskaya str. 48, Moscow (Russian Federation); Zhukovska, S.; Semenov, D.; Henning, Th. [Max-Planck-Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)] [Max-Planck-Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Vasyunin, A. [Department of Chemistry, The University of Virginia, VA (United States)] [Department of Chemistry, The University of Virginia, VA (United States); Birnstiel, T., E-mail: akimkin@inasan.ru, E-mail: dwiebe@inasan.ru, E-mail: pavyar@inasan.ru, E-mail: zhukovska@mpia.de, E-mail: semenov@mpia.de, E-mail: henning@mpia.de, E-mail: anton.vasyunin@gmail.com, E-mail: tbirnstiel@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-03-20T23:59:59.000Z

Note: This page contains sample records for the topic "grain 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

Modeling radiation damage near grain boundary in helium-doped ?-iron  

SciTech Connect (OSTI)

Molecular dynamics (MD) simulations are performed to investigate how ?3<110> (121) symmetric tilt grain boundary (GB) affects point defects and defect clusters in He-doped ?-iron at 300 K in picosecond time scales. Molecular statics calculations are also performed and show that the formation energy is reduced in the GB, and the GB acts as a good sink for point defects especially for interstitial He and self-interstitial atoms (SIAs). It is observed that the average size of HenVm (m>n) clusters becomes smaller in the GB-containing Fe system. It is also found that the number of HenV (n=2, 3) clusters in the GB region decreases, while the number of the HeV clusters increases. The GBs loaded with substitutional or interstitial helium atoms are found to facilitate the growth of helium clusters in the GB region.

Xu, C. P.; Liu, X.-Y; Gao, Fei; Li, Y. H.; Wang, Y. Q.

2014-08-01T23:59:59.000Z

402

Cohesion enhancing effect of magnesium in aluminum grain boundary: A first-principles determination  

SciTech Connect (OSTI)

The effect of magnesium on grain boundary cohesion in aluminum was investigated by means of first-principles calculations using the Rice-Wang model [Rice and Wang, Mater. Sci. Eng. A 107, 23 (1989)]. It is demonstrated that magnesium is a cohesion enhancer with a potency of -0.11 eV/atom. It is further determined through electronic structure and bonding character analysis that the cohesion enhancing property of magnesium is due to a charge transfer mechanism which is unusually strong and overcomes the negative result of the size effect mechanism. Consistent with experimental results, this work clarifies the controversy and establishes that Mg segregation does not contribute to stress corrosion cracking in Al alloys.

Zhang Shengjun; Freeman, Arthur J. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208 (United States); Kontsevoi, Oleg Y. [Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208 (United States); Olson, Gregory B. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States)

2012-06-04T23:59:59.000Z

403

Manufacture and properties of continuous grain flow crankshafts for locomotive and power generation diesel engines  

SciTech Connect (OSTI)

The bulk of the large crankshaft production volume is associated with the medium speed diesel engine market. These engines have seen intense development to obtain higher power outputs without change in the physical size of the crankshaft and at the same time there has been continuing pressure to reduce costs. Fatigue and bearing normal wear are the major technical hurdles that threaten the crankshaft life, and measures for dealing with these issues are described. Continuous grain flow (CGF) crankshafts are responsible for the continued integrity of these enhanced power output engines and the production of these crankshafts is described. Comparisons are made with the older slab forging crankshaft production method. The demand for the medium speed diesel engine and its natural gas derivative is strong and supports an aggressive engine building industry serving locomotive, marine and power generation markets. This demand in turn relies on practical national standards that serve the needs of the engine builder, material supplier and the end user.

Antos, D.J.; Nisbett, E.G. [National Forge Co., Irvine, PA (United States)

1997-12-31T23:59:59.000Z

404

Dry, reconstituted, and early harvested sorghum grain for finishing cattle  

E-Print Network [OSTI]

upon a number of, factors such as diameter& length and revolving speed of the auger. A steady flow of dry grain and water must be maintained into the mixing auger in order to obtain proper and uniform water application. For a given installation... commenced. Reconstituting was accomplish . d by making use of a 70-foot auger conveyor, nine inches in diameter (Figure li. Water was added by metering into a one inch line located above the auger. Grain flow rate was regulated by use of a variable...

Parrett, Ned Albert

1968-01-01T23:59:59.000Z

405

Effects of grain deterioration on sorghum food quality  

E-Print Network [OSTI]

and Bechtel 1978). Storage fungi common on grains grow most rapidly at about 30-32 C, and their growth rate decreases as temperature decreases. Qasem and Christensen (1960), working with samples of maize stored in the laboratory at moisture contents of 16... deteriorated grain was set at about 18%, which allowed fungal growth but not sprouting. Under field conditions, the moisture content is much higher, after a rain or dew, for example. TADI 1. 2 Effeii of Cruin Deterroraciun on tlir I'hysicai amd Chemical...

Domanski, Cristian Estanislao

1983-01-01T23:59:59.000Z

406

Effect of grain on silage characteristics for ruminants  

E-Print Network [OSTI]

. pared the nutritional value of Oro-t, a grain type sorghum, and Fs-lb and Fs-la, two forage type grain sorghums (Bupp, 1973; I:upp, 1975; Spiegel, 1975; and Tolbert et al. , 1975). Tol'oert et al. (1975) indicated that dry matter digestibilities...;ver . enerally higher for she p fed Fs-lb, whereas nitrogen digestibilities and re- tention. ", -er higher f' or sheep fed Oro-t sila=es. They a' so discovered that increasin" head to . ,tover rations increas d d ~ matter digestibi'ities up to a 1:1 ratio...

Groves, William Grady

1977-01-01T23:59:59.000Z

407

Silicate Emission Profiles from Low-Mass Protostellar Disks in the Orion Nebula: Evidence for Growth and Thermal Processing of Grains  

E-Print Network [OSTI]

We present 8--13 micron low resolution spectra (R~100) of 8 low-mass protostellar objects ("proplyds") in the Orion Nebula using the Long Wavelength Spectrometer (LWS) at the W. M. Keck Observatory. All but one of the sources in our sample show strong circumstellar silicate emission, with profiles that are qualitatively similar to those seen in some T Tauri and Herbig Ae/Be stars. The silicate profile in all cases is significantly flattened compared to the profile for typical interstellar dust, suggesting that the dominant emitting grains are significantly larger than those found in the interstellar medium. The 11.3-to-9.8 micron flux ratio--often used as an indicator of grain growth--is in the 0.8 to 1.0 range for all of our targets, indicating that the typical grain size is around a few microns in the surface layers of the attendant circumstellar disk for each object. Furthermore, the silicate profiles show some evidence of crystalline features, as seen in other young stellar objects. The results of our analysis show that the grains in the photoevaporating protostellar disks of Orion have undergone significant growth and perhaps some annealing, suggesting that grain evolution for these objects is not qualitatively different from other young stellar objects.

R. Y. Shuping; Marc Kassis; Mark Morris; Nathan Smith; John Bally

2006-05-05T23:59:59.000Z

408

Critical events, entropy, and the grain boundary character distribution Materials Research Science and Engineering Center  

E-Print Network [OSTI]

Department of Mathematics, The University of Utah, Salt Lake City, UT 84112 D. Kinderlehrer, R. Sharp, and S) or area (in 3D) of interface with a given lattice misorien- tation and normal. During the growth process to the interfacial energy density. In simulation, it is found that if the given energy density depends only

409

Distributed DBMS Introduction  

E-Print Network [OSTI]

Distributed DBMS Outline Introduction What is a distributed DBMS Problems Current state-of-affairs Background Distributed DBMS Architecture Distributed Database Design Semantic Data Control Distributed Query Processing Distributed Transaction Management Parallel Database Systems Distributed Object DBMS

Chen, Yangjun

410

In-situ Phase transformation study in fine grained heat affected zone of Grade 91 steels  

SciTech Connect (OSTI)

Creep strength-enhanced ferritic (CSEF) steels such as the 9 Cr steel [ASTM A387 Grade 91] are widely used as tubing and piping in the new generation of fossil fired power plants. Microstructures in the fine-grained heat affected zone (FGHAZ) may significantly reduce creep strength leading Type IV failures. Current research suggest that reducing pre-weld tempering temperature from 760 C (HTT) to 650 C (LTT) has the potential to double the creep life of these welds. To understand this improvement, time-resolved X-ray diffraction (TRXRD) measurement with synchrotron radiation was used to characterize the microstructure evolution during fine grained heat-affected zone (HAZ) thermal cycling of grade 91 steel. The measurements showed both M23C6 (M=Fe, Cr) and MX (M=Nb, V; X=C,N) are present in the sample after the HTT condition. Near equilibrium fraction of M23C6 was measured in high temperature tempering condition (HTT, 760 C). However, the amount of M23C6 in LTT condition was very low since the diffraction peaks are close to the background. During simulated FGHAZ thermal cycling, the M23C6 partially dissolved in HTT sample. Interestingly, MX did not dissolve in both LTT and HTT samples. Hypothesis for correlation of M23C6 carbide distribution and pre-mature creep failure in FGHAZ will be made.

Babu, Sudarsanam Suresh [Ohio State University; Yamamoto, Yukinori [ORNL; Santella, Michael L [ORNL; Yu, Xinghua [ORNL; Komizo, Prof. Y [Osaka University; Terasaki, Prof. H [Osaka University

2014-01-01T23:59:59.000Z

411

Conditions necessary for capillary hysteresis in porous media: Tests of grain-size and surface tension influences  

E-Print Network [OSTI]

resaturate the gravel or sand pack. Like in the drainingtop of the pack. In coarser (? 7 mm) gravels, the starting

Tokunaga, Tetsu K.; Olson, Keith R.; Wan, Jiamin

2004-01-01T23:59:59.000Z

412

Effects of grain size on the rate-dependent thermomechanical responses of nanostructured superelastic NiTi  

E-Print Network [OSTI]

in situ infrared thermography in the strain rate range from _e = 4 ? 10?5 s?1 to _e = 1 ? 10?1 s?1

Sun, Qing-Ping

413

EFFECTS OF STRENGTH AND GRAIN SIZE ON NEAR-THRESHOLD FATIGUE CRACK GROWTH IN ULTRA-HIGH STRENGTH STEEL  

E-Print Network [OSTI]

Mechanical properties of 300-M steel. FI CUKE CAPT! ONS Fig.lIK) at R ~ (l.OS, for 300-M steel, qUC'IH:iwci and temperedcrack growth (lIKo) in 300-M steel, tesLed in air. Summary

Ritchie, Robert O.

2010-01-01T23:59:59.000Z

414

The effect of WC grain size and cobalt content on properties and electrical discharge machining of WC-Co composites  

E-Print Network [OSTI]

-ray diffraction. The operating temperature is so high that metallic vapors are formed and condense to hollow non-crystalline spheres which deform and crystallize after crushing. A steep temperature gradient exists in the work-piece and the matrix melts to a... required for the application. The usage of WC-Co composites for wear-resistant parts includes mining drills, rriilling balls, high pressure valves and nozzles, and dies 1'or compacting metal powders and/or ceramic materials. Wear-resistant parts which a...

Tsai, Wei-Lung

1988-01-01T23:59:59.000Z

415

Quasi-isentropic and shock compression of FCC and BCC metals : effects of grain size and stacking-fault energy  

E-Print Network [OSTI]

the nickel electrolyte during electrodeposition to stabilizeelectrodeposition method given the relatively thick nc layer. Figure 4.15: As-prepared 30-50 nm nickel

Jarmakani, Hussam N.

2008-01-01T23:59:59.000Z

416

Quasi-isentropic and shock compression of FCC and BCC metals : effects of grain size and stacking-fault energy  

E-Print Network [OSTI]

1 Figure 1.2: (a) Schematic of the NIF facility at LLNL (courtesy of: www.llnl.gov/nif); (b) Schematic of thethat takes place within the target chamber (from LLNL NIF

Jarmakani, Hussam N.

2008-01-01T23:59:59.000Z

417

Investigation of the sheath formation in a dusty plasma containing energetic electrons and nano-size dust grains  

SciTech Connect (OSTI)

Numerical simulations of the stationary multi-fluid equations are used to study the structure of a dusty plasma sheath in the presence of a beam of energetic electrons. It is found that even a small number of energetic electrons can strongly modify the sheath parameters, specially the sheath thickness. Depending on the magnitude of the beam flux, two different regimes of sheath thickness can be recognized; At small beam fluxes, the sheath is in the regime of thin sheath and its thickness grows linearly with the beam flux. As the beam flux increases, at a certain beam energy or beam number density, the sheath demonstrates a sharp transition to the regime of thick sheath where the width is almost three times larger. The beam parameters corresponding to the transition between the two regimes depend on the parameters of the background plasma. The beam transition energy increases with the electron temperature and dust number density while decreases with the dust radius. On the other hand, the beam transition number density is a non-monotonic function of the background plasma number density. The localization of dust particles above the substrate is intensified by the increase in the beam number density.

Foroutan, G.; Akhoundi, A. [Physics Department, Faculty of Science and Nanostructure Material Research Center, Sahand University of Technology, 51335-1996 Tabriz (Iran, Islamic Republic of)

2012-10-15T23:59:59.000Z

418

doi:10.1016/S0016-7037(03)00494-0 Chondrule textures and precursor grain size: an experimental study  

E-Print Network [OSTI]

--Chondrule formation appears to have been a major event in the early solar system, but chondrule properties do was an important process in the early solar system. Whether this was an astro- physical or planetary process crystallization experiments were carried out in a DelTech DT-31-VT-OS muffle tube furnace, using Pt wire loops

419

Ratooning Grain Sorghum on the Texas Gulf Coast  

E-Print Network [OSTI]

Sorghum has characteristics that make it able to regenerate the above-ground portion of the plant. These features allow producers to seek a second grain crop within the same growing year by preparing the old plants immediately after the removal...

Livingston, Stephen; Coffman, Cloyce G.

1997-01-03T23:59:59.000Z

420

Fine-Grained Power Management Using Process-level Profiling  

E-Print Network [OSTI]

. To evaluate energy efficiency, the Green Grid group proposed the definition of power usage effectiveness (PUE between performance and energy consumption, fine-grained methods, such as process- level power management-aware decisions based on these information. In addition, we introduce a power-aware system module called Energy

Shi, Weisong

Note: This page contains sample records for the topic "grain 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

Microwave sintering of sol-gel derived abrasive grain  

DOE Patents [OSTI]

A method is provided for making microwave-sintered, free flowing alpha alumina-based ceramic abrasive grain, under conditions effective to couple microwaves with calcined alpha alumina-based abrasive gain precursor and sinter it at a temperature of at least about 1150.degree. C.

Plovnick, Ross (St. Louis Park, MN); Celikkaya, Ahmet (Woodbury, MN); Blake, Rodger D. (Tuscon, AZ)

1997-01-01T23:59:59.000Z

422

Thermodynamics of Protein Folding from Coarse-Grained Models' Perspectives  

E-Print Network [OSTI]

8 Thermodynamics of Protein Folding from Coarse-Grained Models' Perspectives Michael Bachmann applications. In this lecture, we focus on the anal- ysis of mesoscopic models for protein folding, aggregation for a more universal description of the notoriously difficult problem of protein fold- ing. In this approach

Janke, Wolfhard

423

On-Farm Storage and Disposal of Sorghum Grain.  

E-Print Network [OSTI]

APRIL 1963 ON-FARM - STORAGE AND DISPOSAL OF SORGHUM GRAIN -- THE AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS TEXAS AGRICULTURAL EXPERIMENT STATION R. E. PATTERSON. DIRECTOR. COLLEGE ST+TION, TEXAS IN COOPERATION WITH THE U. S. DEPARTMENT... OF AGRICULTURE summary The sorghum storage space. Utilization increases resulted from an increased awareness and acceptance by feeders and millers...

Brown, Charles W.; Moore, Clarence A.

1963-01-01T23:59:59.000Z

424

January 2002 Wild Oat Control In Small Grains -2002  

E-Print Network [OSTI]

January 2002 Wild Oat Control In Small Grains - 2002 Beverly R. Durgan Weed Scientist - University of Minnesota Good wild oat control with any herbicide requires proper timing of applications. Postemergence wild oat herbicides require application to wild oats and crops at precise leaf stages. Leaf number

Minnesota, University of

425

January 2006 Wild Oat Control In Small Grains -2006  

E-Print Network [OSTI]

1 January 2006 Wild Oat Control In Small Grains - 2006 Beverly R. Durgan Weed Scientist - University of Minnesota Good wild oat control with any herbicide requires proper timing of applications. Postemergence wild oat herbicides require application to wild oats and crops at precise leaf stages. Leaf number

Minnesota, University of

426

FEA Simulations of Magnets with Grain Oriented Steel  

SciTech Connect (OSTI)

One of the potential successors of the Large Hadron Collider is a Muon Col- lider. Muons are short-lived particles, which therefore require fast acceleration. One potential avenue is a very fast cycling cyclotron, where the bending is sup- plied by a combination of fixed-field superconducting magnets and fast ramping normal conducting iron-cored coils. Due to the high ramping rate (around 1 kHz) eddy current and hysteresis losses are a concern. One way to overcome these is by using grain-oriented soft-iron, which promises superior magnetic properties in the direction of the grains. This note summarizes efforts to include the anisotropic material properties of grain-oriented steel in finite element analysis to predict the behaviour of the dipole magnets for this accelerator. It was found that including anisotropic material properties has a detrimental effect on model convergence. During this study it was not possible to include grain oriented steel with an accuracy necessary to study the field quality of a dipole magnet.

Witte H.

2012-08-06T23:59:59.000Z

427

Presolar Silicate Grains: Constraints on Solar System Processes and  

E-Print Network [OSTI]

Presolar Silicate Grains: Constraints on Solar System Processes and Stellar Nucleosynthesis 63130, USA. (floss@wustl.edu) Presolar silicates are among the most abundant type of stardust and have. This is particularly true for presolar silicates, which are more susceptible to secondary processing than other, more

Floss, Christine

428

On the Absorption and Emission Properties of Interstellar Grains  

E-Print Network [OSTI]

Our current understanding of the absorption and emission properties of interstellar grains are reviewed. The constraints placed by the Kramers-Kronig relation on the wavelength-dependence and the maximum allowable quantity of the dust absorption are discussed. Comparisons of the opacities (mass absorption coefficients) derived from interstellar dust models with those directly estimated from observations are presented.

Aigen Li

2005-03-25T23:59:59.000Z

429

Criteria for mixing rules application for inhomogeneous astrophysical grains  

E-Print Network [OSTI]

The analysis presented in this paper verifies which of the mixing rules are best for real components of interstellar dust in possible wide range of wavelengths.The DDA method with elements of different components with various volume fractions has been used. We have considered 6 materials: ice, amorphous carbon, graphite, SiC, silicates and iron, and the following mixing rules: Maxwell-Garnett, Bruggeman, Looyenga, Hanay and Lichtenecker which must satisfy rigorous bounds. The porous materials have also been considered. We have assumed simplified spatial distribution, shape and size of inclusions. The criteria given by \\citet{draine1988} have been used to determine the range of wavelengths for the considered mixtures in order to calculate the ${\\rm Q_{ext}}$ using the DDA. From all chosen mixing rules for the examined materials in majority of cases (13 out of 20) the best results have been obtained using the Lichtenecker mixing rule. In 5 cases this rule is better for some volume fraction of inclusions.

Napoleon Maron; Olaf Maron

2008-09-06T23:59:59.000Z

430

METER-SIZED MOONLET POPULATION IN SATURN'S C RING AND CASSINI DIVISION  

SciTech Connect (OSTI)

Stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph reveal the presence of transparent holes a few meters to a few tens of meters in radial extent in otherwise optically thick regions of the C ring and the Cassini Division. We attribute the holes to gravitational disturbances generated by a population of {approx}10 m boulders in the rings that is intermediate in size between the background ring particle size distribution and the previously observed {approx}100 m propeller moonlets in the A ring. The size distribution of these boulders is described by a shallower power-law than the one that describes the ring particle size distribution. The number and size distribution of these boulders could be explained by limited accretion processes deep within Saturn's Roche zone.

Baillie, Kevin; Colwell, Joshua E. [Department of Physics, University of Central Florida, Orlando, FL 32816-2385 (United States); Esposito, Larry W. [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, 392 UCB, Boulder, CO 80309-0392 (United States); Lewis, Mark C., E-mail: kevin.baillie@cea.fr [Department of Computer Science, Trinity University, One Trinity Place, San Antonio, TX 78212-7200 (United States)

2013-06-01T23:59:59.000Z

431

The evolutionary consequences of oxygenic photosynthesis: a body size perspective  

E-Print Network [OSTI]

at lower O2:CO2. Field studies of size distributions across extant higher taxa and individual species of Biology, University of New Mexico, Albuquerque, NM 87131, USA M. Kowalewski Department of Geosciences transport limits the thickness or volume-to-surface area ratio--rather than mass or volume

Lyons, S. Kathleen

432

Structure, chemistry, and stress corrosion cracking of grain boundaries in alloys 600 and 690  

SciTech Connect (OSTI)

The microstructure in six commercial batches of alloys 600 and 690 has been investigated using scanning electron microscopy (SEM), analytical transmission electron microscopy (ATEM), atom probe field ion microscopy (APFIM), and secondary ion mass spectroscopy (SIMS). The materials were also tested with respect to their resistance to intergranular stress corrosion cracking (IGSCC) in high-purity water at 365 C. Applied microanalytical techniques allowed direct measurement of carbon concentration in the matrix together with determination of grain boundary microstructure and microchemistry in all material conditions. The distribution of oxygen near a crack in material tested with respect to IGSCC was also investigated. The role of carbon and chromium and intergranular precipitates on IGSCC is discussed.

Stiller, K. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Physics; Nilsson, J.O. [AB Sandvik Steel, Sandviken (Sweden); Norring, K. [Studsvik Material AB, Nykoeping (Sweden)

1996-02-01T23:59:59.000Z

433

Large amplitude dust-acoustic solitary waves in electron-positron-ion plasma with dust grains  

SciTech Connect (OSTI)

Propagation of large amplitude dust-acoustic (DA) solitary waves is investigated in electron-positron-ion plasmas in the presence of dust grains using Sagdeev potential method. It is shown that acceptable values of Mach number for propagation of the large amplitude DA solitary waves depend strongly on plasma parameters. It is also observed that the amplitude of DA solitary waves increases as both the Mach number M and dust charge Z{sub d} are increased. Furthermore, it is found that a dusty plasma with inertial dust fluid and Boltzmann distributed electrons, positrons, and ions admits only negative solitary potentials associated with nonlinear dust-acoustic waves. In addition, it is remarked that the formation of double layers is not possible in this plasma system.

Esfandyari-Kalejahi, A.; Afsari-Ghazi, M.; Noori, K.; Irani, S. [Department of Physics, Faculty of Science, Azarbaijan University of Shahid Madani, 51745-406, Tabriz (Iran, Islamic Republic of)

2012-08-15T23:59:59.000Z

434

Children's Clothes - Size and Selection.  

E-Print Network [OSTI]

Tooe ZTA245.7 8-1303 B873 no ? \\'3J~3L-~=============i1 ? ? ? CHILDREN'S CLOTHES, SIZE AND SELECTION ? ~========================~ Texas Agricultural Extension Service. The Texas A&M University System. Daniel C. pfannstiel, Director.... College Station, Texas ," ? (BIaBk Pa,ge in O'rigjaal Bulletinl ' / I' j '. ":SIZE AND SELECTION Ann Vanderpoorten and Claudia Kerbel* Preschool and school-age children have special...

Vanderpoorten, Ann; Kerbel, Claudia

1980-01-01T23:59:59.000Z

435

Modeling the Motion and Distribution of Interstellar Dust inside the Heliosphere  

E-Print Network [OSTI]

The interaction of dust grains originating from the local interstellar cloud with the environment inside the heliosphere is investigated. As a consequence of this interaction the spatial distribution of interstellar dust grains changes with time. Since dust grains are charged in the interplanetary plasma and radiation environment, the interaction of small grains with the heliosphere is dominated by their coupling to the solar wind magnetic field. The change of the field polarity with the solar cycle imposes a temporal variation of the spatial distribution and the flux of small (radius smaller than $0.4 \\mu m$) interstellar dust grains in the Solar System, whereas the flux of large grains is constant because of their negligible coupling to the solar wind magnetic field. The flux variation observed by in-situ measurements of the Galileo and Ulysses spacecraft are reproduced by simulating the interaction of interstellar grains with charge-to-mass ratios between $0.5 C/kg^{-1}$ and $1.4 C/kg$ with the interplanetary environment.

M. Landgraf

1999-06-17T23:59:59.000Z

436

Mechanical Properties and Radiation Tolerance of Ultrafine Grained and Nanocrystalline Metals  

E-Print Network [OSTI]

loops. Here we provide experimental evidence that high angle grain boundaries can effectively remove radiation-induced defects. The equal channel angular pressing (ECAP) technique was used to produce ultrafine grained Fe-Cr-Ni alloy. Mechanical...

Sun, Cheng

2013-04-26T23:59:59.000Z

437

Grain-boundary engineering markedly reduces susceptibility to intergranular hydrogen embrittlement in metallic materials  

E-Print Network [OSTI]

Grain-boundary engineering markedly reduces susceptibility to intergranular hydrogen embrittlement. Keywords: Hydrogen embrittlement; Intergranular cracking; Grain-boundary engineering; Special boundaries,e,* a Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA b

Ritchie, Robert

438

Abundances of presolar silicon carbide grains in primitive meteorites determined by NanoSIMS  

E-Print Network [OSTI]

Abundances of presolar silicon carbide grains in primitive meteorites determined by NanoSIMS Jemma carbide (SiC) grains estimated from their noble gas components show significant variations in even

Nittler, Larry R.

439

Modeling Elasto-Plastic Behavior of Polycrystalline Grain Structure of Steels at Mesoscopic Level  

E-Print Network [OSTI]

Modeling Elasto-Plastic Behavior of Polycrystalline Grain Structure of Steels at Mesoscopic Level. The constitutive model of crystal grains utilizes anisotropic elasticity and crystal plasticity. Commercially be considered macroscopically homogeneous. Elastic and rate independent plastic deformation modes are considered

Cizelj, Leon

440

Influence of grain boundary energy on the nucleation of complexion transitions  

E-Print Network [OSTI]

Influence of grain boundary energy on the nucleation of complexion transitions Stephanie A different transition tem- peratures. It has been hypothesized that higher energy grain boundaries have relative energies preferentially undergo complexion transitions. Our experiment uses a unique sandwich

Rohrer, Gregory S.

Note: This page contains sample records for the topic "grain 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

Low-Cycle Fatigue of Ultra-Fine-Grained Cryomilled 5083 Aluminum Alloy  

E-Print Network [OSTI]

of an Ultra-Fine Grained Aluminum Alloy, Poster Session,Grained Cryomilled 5083 Aluminum Alloy J.L. WALLEY, E.J.consistent with other MA aluminum alloys and is attributed

Walley, J. L.; Lavernia, E. J.; Gibeling, J. C.

2009-01-01T23:59:59.000Z

442

Sequence stratigraphy, facies architecture and reservoir distribution, Cretaceous lowstand fan reservoirs, Southern Basin, onshore Trinidad  

SciTech Connect (OSTI)

Thick Albian-Campanian mass-flow sandstones in the Southern Basin Trinidad were deposited within submarine canyons incised into the northern continental slope of South America and as associated down-dip basin-floor lowstand fans. The contemporaneous slope to basin-floor break lay across the Southern Basin area with turbidity current paleoflow being to the northwest. North of this paleo-slope break graded to massive, channelized, high-density turbidite sandstones occur interstratified with shaly overbank and channel abandonment deposits. A progression of depositional sub-environments from proximal through distal lowstand fan can be recognized. All fine and thin upward but can be discriminated by the occurrence of slumps, debris flows and conglomerates, the grain-size and bedding scale of sandstones and the characteristics of low-density turbidites and mudrocks. South of the paleo-slope break mass-flow deposits comprise muddy slumps and debris flows rich in granules and pebbles deposited in slope canyons. During periods of turbidity current by-pass or fan abandonment hemipelagic settling processes predominated. Reservoir distribution maps of these lowstand fans have been constructed utilizing geometric constraints, analogs and paleoslope determinations from oriented core. The interpreted canyon locations and orientations are key to the understanding of reservoir distribution on the basin-floor tract to the north: a vital component in the exploration of the basin.

Sprague, A.R.; Larue, D.K.; Faulkner, B.L. [Exxon Production Research Company, Houston, TX (United States)] [and others

1996-08-01T23:59:59.000Z

443

Grain boundary microstructure, chemistry, and IGSCC in Alloy 600 and Alloy 690  

SciTech Connect (OSTI)

The resistance to intergranular stress corrosion cracking of six different Alloy 600 and Alloy 690 steam generator tubes has been investigated. The composition of the materials at grain boundaries has been investigated using analytical transmission electron microscopy and atom probe field ion microscopy techniques. The depletion of chromium at the grain boundaries has been related to the type of grain boundary precipitates. Segregation of carbon and boron to the grain boundaries has been observed and quantified.

Norring, K. [Studsvik AB, Nykoeping (Sweden); Stiller, K. [Chalmers Univ. of Technology, Goeteborg (Sweden); Nilsson, J.O. [AB Sandvik Steel, Sandviken (Sweden)

1992-12-31T23:59:59.000Z

444

Effect of grain orientation on ductility in a nanocrystalline Ni-Fe alloy  

SciTech Connect (OSTI)

The influence of columnar grain geometry on mechanical property was studied in an electrodeposited nanocrystalline Ni-Fe alloy. The compressive results show that the strength is independent of grain orientation. However, the plastic strain increased remarkably when the loading axis is parallel to the direction of grain columns, which is due to the enhanced grain boundary and dislocation activities. The significance of the current study is that a new strategy was developed to improve the ductility of nanocrystalline materials.

Li, Hongqi [Los Alamos National Laboratory; Misra, Amit [Los Alamos National Laboratory; Liaw, Peter K [UNIV OF TENN; Choo, Hahn [UNIV OF TENN

2008-01-01T23:59:59.000Z

445

Magnetorotational instability in plasmas with mobile dust grains  

SciTech Connect (OSTI)

The magnetorotational instability of dusty plasmas is investigated using the multi-fluid model and the general dispersion relation is derived based on local approximation. The dust grains are found to play an important role in the dispersion relation in the low-frequency mode and exhibit destabilizing effects on the plasma. Both the instability criterion and growth rate are affected significantly by the dust and when the dust is heavy enough to be unperturbed, the reduced dispersion relations are obtained. The instability criteria show that the dust grains have stabilizing effects on the instability when the rotation frequency decreases outwards and conversely lead to destabilizing effects when the rotation frequency increases outwards. The results are relevant to accession and protoplanetary disks.

Ren Haijun [CAS Key Laboratory of Basic Plasma Physics, Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Cao Jintao [Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Li Ding [CAS Key Laboratory of Basic Plasma Physics, Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

2013-03-15T23:59:59.000Z

446

Grain boundary characterization in an X750 alloy  

SciTech Connect (OSTI)

Grain boundary chemistry in an X750 Ni alloy was analyzed by atom probe tomography in an effort to clarify the possible roles of elemental segregation and carbide presence on the stress corrosion cracking behavior of Ni alloys. Two types of cracks are observed: straight cracks along twin boundaries and wavy cracks at general boundaries. It was found that carbides (M23C6 and TiC) are present at both twin and general boundaries, with comparable B and P segregation for all types of grain boundaries. Twin boundaries intercept ? precipitates while the general boundaries wave around the ? and carbide precipitates. Near a crack tip, oxidation takes place on the periphery of carbide precipitate.

Kevin Fisher; Sebastien Teysseyre; Emmanuelle Marquis

2012-11-01T23:59:59.000Z

447

A nucleotide-level coarse-grained model of RNA  

E-Print Network [OSTI]

We present a new, nucleotide-level model for RNA, oxRNA, based on the coarse-graining methodology recently developed for the oxDNA model of DNA. The model is designed to reproduce structural, mechanical and thermodynamic properties of RNA, and the coarse-graining level aims to retain the relevant physics for RNA hybridization and the structure of single- and double-stranded RNA. In order to explore its strengths and weaknesses, we test the model in a range of nanotechnological and biological settings. Applications explored include the folding thermodynamics of a pseudoknot, the formation of a kissing loop complex, the structure of a hexagonal RNA nanoring, and the unzipping of a hairpin motif. We argue that the model can be used for efficient simulations of the structure of systems with thousands of base pairs, and for the assembly of systems of up to hundreds of base pairs. The source code implementing the model is released for public use.

ulc, Petr; Ouldridge, Thomas E; Doye, Jonathan P K; Louis, Ard A

2014-01-01T23:59:59.000Z

448

A nucleotide-level coarse-grained model of RNA  

E-Print Network [OSTI]

We present a new, nucleotide-level model for RNA, oxRNA, based on the coarse-graining methodology recently developed for the oxDNA model of DNA. The model is designed to reproduce structural, mechanical and thermodynamic properties of RNA, and the coarse-graining level aims to retain the relevant physics for RNA hybridization and the structure of single- and double-stranded RNA. In order to explore its strengths and weaknesses, we test the model in a range of nanotechnological and biological settings. Applications explored include the folding thermodynamics of a pseudoknot, the formation of a kissing loop complex, the structure of a hexagonal RNA nanoring, and the unzipping of a hairpin motif. We argue that the model can be used for efficient simulations of the structure of systems with thousands of base pairs, and for the assembly of systems of up to hundreds of base pairs. The source code implementing the model is released for public use.

Petr ulc; Flavio Romano; Thomas E. Ouldridge; Jonathan P. K. Doye; Ard A. Louis

2014-03-17T23:59:59.000Z

449

Performance of Large grain and Single Crystal Niobium Cavities  

SciTech Connect (OSTI)

We have fabricated and tested several single and one multi-cell cavity made from large grain niobium of four different ingots. Two cavities at a frequency of ~ 2.2 GHz were made from single crystal sheets. Large grain material was used for four single cell cavities of the HG and OC shapes, a 7-cell cavity of the HG shape all resonating at 1500 MHz and an ILC_LL single cell cavity at 1300 MHz. We began to explore also different chemical polishing baths such as a 1:1:1 and a 1:1:2 buffered solution and explored the change of cavity performance as a function of material removal. The results from these preliminary investigations are reported in this contribution.

Kneisel, Peter; Ciovati, Gianluigi; Sekutowicz, Jacek

2006-07-01T23:59:59.000Z

450

Kinetically determined shapes of grain boundaries in CVD graphene  

E-Print Network [OSTI]

Predicting the shape of grain boundaries is essential to control results of the growth of large graphene crystals. A global energy minimum search predicting the most stable final structure contradicts experimental observations. Here we present Monte Carlo simulation of kinetic formation of grain boundaries (GB) in graphene during collision of two growing graphene flakes. Analysis of the resulting GBs for the full range of misorientation angles $\\alpha$ allowed us to identify a hidden (from post facto analysis such as microscopy) degree of freedom - the edge misorientation angle $\\beta$. Edge misorientation characterizes initial structure rather than final structure and therefore provides more information about growth conditions. Use of $\\beta$ enabled us to explain disagreements between the experimental observations and theoretical work. Finally, we report an analysis of an interesting special case of zero-tilt GBs for which structure is determined by two variables describing the relative shift of initial isl...

Bets, Ksenia V; Yakobson, Boris I

2014-01-01T23:59:59.000Z

451

Comment on "The shape and composition of interstellar silicate grains"  

E-Print Network [OSTI]

This Comment is in response to an Erratum to the paper entitled "The shape and composition of interstellar silicate grains" (Min et al., A&A, 462, 667-676 (2007). The Erratum corrects erroneously cited data but upholds the paper's original conclusions that GEMS are not remnant interstellar grains and that most GEMS formed in the early solar system. In our Comment, we show that the correct data in fact strengthen the relationship between GEMS and interstellar silicates, contrary to the conclusions of Min et al. in their Erratum. We also explore the validity of the isotopic and bulk chemical bases for comparison and present additional indicators of past ISM radiation processing of silicates.

J. P. Bradley; H. A. Ishii

2008-04-17T23:59:59.000Z

452

Evaluating chemical and physical properties of grain dust for use in an explosion hazard indicator  

E-Print Network [OSTI]

. 06 iIm 15. 0 0 ) 15. 6 10. 0 5. 0 3 4 7. 2 8. 5 5 6 4 0 . . . 3. 3 1. 7 1. 7 14 1 ~ 5 12 3. 0 0. 0 O CV O Yl CO O CO O N I I I O O ICI I CI O CC I CI cn 4 0 CV ch I CO I O O CO I O I O C: CI I Particle Size Ranges... 3 Q 2. 1 0. 6 0. 6 I CI CI 6 IO Yl CD 0 CI P4 I I I I I I CI N N 0 Yl (O I CI C) I U3 CI co I I CI CI CI I m Particle Size Ranges, um FIG. 14 Coulter Counter particle size distribution of rice dust, 30. 0 25. 0 20. 0 Mean...

Plemons, Dorothy Sue

1981-01-01T23:59:59.000Z

453

Research on Farm Drying and Storage of Sorghum Grain.  

E-Print Network [OSTI]

Deterioration. Cereal Chemistry. Vol. 34, No. 4, pp. 226-33. July 1957. (3) Neal, E. M., R. A. Hall and J. H. Jones. Live and Dead Germ Sorghum Grain in Steer Fattening Rations. Progress Report 1702. Texas Agricultural Experiment Station. July 1954. (4... of the following individuals: M. M. Garcia, of Substation No. 4, Beaumont, Texas, for his assistance in conducting the tests : M. D. Whitehead, formerly associate professor, Department of Plant Physiology and Path- ology, College Station, Texas, for conducting...

Redlinger, L. M.; Davenport, M. G.; Sorenson Jr., J. W.; Kline, G. L.; Aldred, W. H.

1957-01-01T23:59:59.000Z

454

Statistics of turbulence via polarimetry: alignment of grains and atoms  

E-Print Network [OSTI]

Most astrophysical fluids are turbulent and magnetized. Fluctuations of polarization provide a promising way to study astrophysical magnetic turbulence. We discuss polarization that arises from grains and atoms aligned in respect to magnetic field, describe the processes of alignment, explain when the alignment reflects the direction of magnetic field. We show that temporal fluctuations of interplanetary magnetic field can be studied using aligned sodium atoms.

A. Lazarian; Huirong Yan

2005-05-29T23:59:59.000Z

455

Intergranular degradation assessment via random grain boundary network analysis  

DOE Patents [OSTI]

A method is disclosed for determining the resistance of polycrystalline materials to intergranular degradation or failure (IGDF), by analyzing the random grain boundary network connectivity (RGBNC) microstructure. Analysis of the disruption of the RGBNC microstructure may be assess the effectiveness of materials processing in increasing IGDF resistance. Comparison of the RGBNC microstructures of materials exposed to extreme operating conditions to unexposed materials may be used to diagnose and predict possible onset of material failure due to

Kumar, Mukul (San Ramon, CA); Schwartz, Adam J. (Pleasanton, CA); King, Wayne E. (San Ramon, CA)

2002-01-01T23:59:59.000Z

456

A Study of the Grain Boundaries and Hydrogen in HF-CVD Diamond Films  

E-Print Network [OSTI]

composition of grain boundaries in polycrystalline diamond lms by transmission electron microscopy and highA Study of the Grain Boundaries and Hydrogen in HF-CVD Diamond Films Israel Yoel Koenka #12;A Study of the Grain Boundaries and Hydrogen in HF-CVD Diamond Films Research Thesis In partial fulllment

Adler, Joan

457

The Use of Conditioned Air for Maintaining Quality of Stored Sorghum Grain.  

E-Print Network [OSTI]

.- ...... '. .................................... 21 .............................................. Design Method No: 3 21 Effects of Conditioned-air Storage on Grain Quality ........................................................... II! Insect Control...,~ of controlled storage environments for bulk yain are discussed. The initial vapor pressure of tile moisture in the grain and the partial pressure of !lie vapor in the conditioned air circulating through llle grain mass were found to be very important tl...

Person, Nat K. Jr.; Sorenson, J. W. Jr.; McCune, W. E.; Hobgood, Price

1967-01-01T23:59:59.000Z

458

South Carolina Pest Management Handbook for Field Crops 2014 FARM-STORED GRAIN INSECT MANAGEMENT  

E-Print Network [OSTI]

are loaded, clean up all spilled grain. Keep ground around bins clear of weeds and debris. Proper storage the grain is loaded into the bin for storage. After loading the best you can do is to try to maintain this level of quality. Thus, it is important to maximize the quality of your grain prior to storage

Duchowski, Andrew T.

459

South Carolina Pest Management Handbook for Field Crops 2013 FARM-STORED GRAIN INSECT MANAGEMENT  

E-Print Network [OSTI]

, clean up all spilled grain. Keep ground around bins clear of weeds and debris. Proper storage management the grain is loaded into the bin for storage. After loading the best you can do is to try to maintain this level of quality. Thus, it is important to maximize the quality of your grain prior to storage

Stuart, Steven J.

460

Pressure Solution: Possible Mechanism for Silicate Grain Dissolution in a Petrocalcic Horizon  

E-Print Network [OSTI]

Pressure Solution: Possible Mechanism for Silicate Grain Dissolution in a Petrocalcic Horizon H in southern New Mexico, up to 58% of the silicate grains have dissolution fea- tures, such as embayed-solution mechanism in the petrocaIcic horizon: (i) silicate grains are smooth where they contact pores, but serrated

Ahmad, Sajjad

Note: This page contains sample records for the topic "grain 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

CONTINUED INVESTIGATION OF PRESOLAR SILICATE GRAINS IN THE CARBONACEOUS CHONDRITE NINGQIANG. X. Zhao1,2  

E-Print Network [OSTI]

CONTINUED INVESTIGATION OF PRESOLAR SILICATE GRAINS IN THE CARBONACEOUS CHONDRITE NINGQIANG. X in extraterrestrial materials, silicate grains can help us investigate the nucleosynthetic processes and evolution of their parent stellar sources. Numerous studies have been carried out to search for presolar silicate grains

462

Strain modification in thin Si1 x yGexCy alloys on ,,100... Si for formation of high density and uniformly sized quantum dots  

E-Print Network [OSTI]

size, increase the density of islands, and significantly narrow the distribution of island sizes for dislocation generation within the three-dimensional islands, w