National Library of Energy BETA

Sample records for grain size distribution

  1. Grain-size distributions of tsunami sediments 

    E-Print Network [OSTI]

    Spencer, Sarah

    2011-08-08

    tsunamis, Chile 2010 and Peru 2008. The grain-size of the sediment from each tsunami was measured by two common techniques: sieving and digital particle counter. To interpret this real tsunami data, numerical and analytical analysis were used to simulate...

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

    SciTech Connect (OSTI)

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

    2013-09-01

    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.

  3. Notes on representing grain size distributions obtained by electron backscatter diffraction

    SciTech Connect (OSTI)

    Toth, Laszlo S., E-mail: laszlo.metz@univ-lorraine.fr [Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR 7239, CNRS/Université de Lorraine, F-57045 Metz (France); Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (DAMAS), Université de Lorraine (France); Biswas, Somjeet, E-mail: somjeetbiswas@gmail.com [Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (DAMAS), Université de Lorraine (France); Gu, Chengfan, E-mail: chengfan.gu@unsw.edu.au [School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052 (Australia); Beausir, Benoit, E-mail: benoit.beausir@univ-lorraine.fr [Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR 7239, CNRS/Université de Lorraine, F-57045 Metz (France); Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (DAMAS), Université de Lorraine (France)

    2013-10-15

    Grain size distributions measured by electron backscatter diffraction are commonly represented by histograms using either number or area fraction definitions. It is shown here that they should be presented in forms of density distribution functions for direct quantitative comparisons between different measurements. Here we make an interpretation of the frequently seen parabolic tales of the area distributions of bimodal grain structures and a transformation formula between the two distributions are given in this paper. - Highlights: • Grain size distributions are represented by density functions. • The parabolic tales corresponds to equal number of grains in a bin of the histogram. • A simple transformation formula is given to number and area weighed distributions. • The particularities of uniform and lognormal distributions are examined.

  4. Low pressure shock initiation of porous HMX for two grain size distributions and two densities

    SciTech Connect (OSTI)

    Gustavsen, R.L.; Sheffield, S.A.; Alcon, R.R.

    1995-09-01

    Shock initiation measurements have been made on granular HMX (octotetramethylene tetranitrainine) for two particle size distributions and two densities. Samples were pressed to either 65% or 73% of crystal density from fine ({approx} 10 {mu}m grain size) and coarse (broad distribution of grain sizes peaking at {approx} 150 {mu}m) powders. Planar shocks of 0.2--1 GPa were generated by impacting gas gun driven projectiles on plastic targets containing the HMX. Wave profiles were measured at the input and output of the {approx} 3.9 mm thick HMX layer using electromagnetic particle velocity gauges. The initiation behavior for the two particle size distributions was very different. The coarse HMX began initiating at input pressures as low as 0.5 GPa. Transmitted wave profiles showed relatively slow reaction with most of the buildup occurring at the shock front. In contrast, the fine particle HMX did not begin to initiate at pressures below 0.9 GPa. When the fine powder did react, however, it did so much faster than the coarse HMX. These observations are consistent with commonly held ideas about bum rates being correlated to surface area, and initiation thresholds being correlated with the size and temperature of the hot spots created by shock passage. For each size, the higher density pressings were less sensitive than the lower density pressings.

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

    E-Print Network [OSTI]

    Daniel, William Marvin

    1973-01-01

    THE EFFECT OF SAND GRAIN SIZE DISTRIBUTION ON THE MINIMUM OIL SATURATION NECESSARY TO SUPPORT IN-SITU COMBUSTION A Thesis by WILLIAM MARVIN DANIEL Submitted to the Graduate College of Texas ARM University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE May 1973 Major Subject: Petroleum. Engineering THE EFFECT OF SAND GRAIN SIZE DISTRIBUTION ON THE MINIMUM OIL SATURATION NECESSARY TO SUPPORT IN-SITU COMBUSTION A Thesis by WILLIAM MARVIN DANIEL Approved...

  6. Solitary Dust--Acoustic Waves in a Plasma with Two-Temperature Ions and Distributed Grain Size

    E-Print Network [OSTI]

    V. V. Prudskikh

    2008-12-02

    The propagation of weakly nonlinear dust--acoustic waves in a dusty plasma containing two ion species with different temperatures is explored. The nonlinear equations describing both the quadratic and cubic plasma nonlinearities are derived. It is shown that the properties of dust--acoustic waves depend substantially on the grain size distribution. In particular, for solitary dust--acoustic 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 large that that in the case of unusized grains.

  7. Shoreline, grain-size, and total-carbon distribution changes before and after Hurricane Alicia, Galveston Island, Texas, 1983

    SciTech Connect (OSTI)

    Rothammer, C.M.; Morrison, L.R.; Warkentin, S.L.

    1985-02-01

    Shoreline, grain-size, and sediment total-carbon changes were monitored, on a monthly basis, on three Galveston Island beaches, from January through December 1983. The study area included: (1) East Beach, obstructed by groins and a seawall; (2) Galveston Island State Park, obstructed by fences artificially stabilizing the dunes; and (3) West Beach, an unobstructed beach. Beach profiles revealed the effects of beach obstruction, such as erosion and undercutting at East Beach, and truncation of the dunes at Galveston Island State Park. Approximately 20 m of expansional cutback occurred on the beaches after Hurricane Alicia hit on August 18, 1983. Contour maps of grain-size and total-carbon distributions reflect the movement of beach sand by either onshore-offshore transport during low-energy periods, or longshore, edge-wave transport during high-energy periods. Statistical analyses revealed a small variation in grain size throughout the year. There were well-defined times of either no correlation or strong correlation between total carbon vs. mean grain size, skewness vs. mean grain size, kurtosis vs. mean grain size, skewness vs. mean grain size, kurtosis vs. mean grain size, total carbon vs. percent sand, total carbon vs. skewness, and skewness vs. kurtosis. Strong correlation was found in response to high-energy events, whereas no correlation was found in response to low-energy events. Galveston Island is undergoing net erosion and appears to be in a metastable state, still capable of responding to oceanographic conditions. The economic effects of Hurricane Alicia include considerable loss of the shoreline and destruction of property. Beach nourishment appears to be the only economically feasible solution to counteract the extensive erosion.

  8. Extracting magnetic cluster size and its distributions in advanced perpendicular recording media with shrinking grain size using small angle x-ray scattering

    SciTech Connect (OSTI)

    Mehta, Virat; Ikeda, Yoshihiro; Takano, Ken; Terris, Bruce D.; Hellwig, Olav; Wang, Tianhan; Wu, Benny; Graves, Catherine; Dürr, Hermann A.; Scherz, Andreas; Stöhr, Jo

    2015-05-18

    We analyze the magnetic cluster size (MCS) and magnetic cluster size distribution (MCSD) in a variety of perpendicular magnetic recording (PMR) media designs using resonant small angle x-ray scattering at the Co L{sub 3} absorption edge. The different PMR media flavors considered here vary in grain size between 7.5 and 9.5?nm as well as in lateral inter-granular exchange strength, which is controlled via the segregant amount. While for high inter-granular exchange, the MCS increases rapidly for grain sizes below 8.5?nm, we show that for increased amount of segregant with less exchange the MCS remains relatively small, even for grain sizes of 7.5 and 8?nm. However, the MCSD still increases sharply when shrinking grains from 8 to 7.5?nm. We show evidence that recording performance such as signal-to-noise-ratio on the spin stand correlates well with the product of magnetic cluster size and magnetic cluster size distribution.

  9. 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)

    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)

    2013-09-01

    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.

  10. Grain size dependence of barchan dune dynamics

    E-Print Network [OSTI]

    C. Groh; N. Aksel; I. Rehberg; C. Kruelle

    2008-11-28

    The dependence of the barchan dune dynamics on the size of the grains involved is investigated experimentally. Downsized barchan dune slices are observed in a narrow water flow tube. The relaxation time from an initial symmetric triangular heap towards an asymmetric shape attractor increases with dune mass and decreases with grain size. The dune velocity increases with grain size. In contrast, the velocity scaling and the shape of the barchan dune is independent of the size of the grains.

  11. The dust grain size - stellar luminosity trend in debris discs

    E-Print Network [OSTI]

    Pawellek, Nicole

    2015-01-01

    The cross section of material in debris discs is thought to be dominated by the smallest grains that can still stay in bound orbits despite the repelling action of stellar radiation pressure. Thus the minimum (and typical) grain size $s_\\text{min}$ is expected to be close to the radiation pressure blowout size $s_\\text{blow}$. Yet a recent analysis of a sample of Herschel-resolved debris discs showed the ratio $s_\\text{min}/s_\\text{blow}$ to systematically decrease with the stellar luminosity from about ten for solar-type stars to nearly unity in the discs around the most luminous A-type stars. Here we explore this trend in more detail, checking how significant it is and seeking to find possible explanations. We show that the trend is robust to variation of the composition and porosity of dust particles. For any assumed grain properties and stellar parameters, we suggest a recipe of how to estimate the "true" radius of a spatially unresolved debris disc, based solely on its spectral energy distribution. The r...

  12. Grain size effects on the fatigue response of nanocrystalline materials

    E-Print Network [OSTI]

    Hanlon, Timothy, 1977-

    2004-01-01

    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 ...

  13. Novel ultrafine grain size processing of soft magnetic materials.

    SciTech Connect (OSTI)

    Michael, Joseph Richard; Robino, Charles Victor

    2009-01-01

    High performance soft magnetic alloys are used in solenoids in a wide variety of applications. These designs are currently being driven to provide more margin, reliability, and functionality through component size reductions; thereby providing greater power to drive ratio margins as well as decreases in volume and power requirements. In an effort to produce soft magnetic materials with improved properties, we have conducted an initial examination of one potential route for producing ultrafine grain sizes in the 49Fe-49Co-2V alloy. The approach was based on a known method for the production of very fine grain sizes in steels, and consisted of repeated, rapid phase transformation cycling through the ferrite to austenite transformation temperature range. The results of this initial attempt to produce highly refined grain sizes in 49Fe-49Co-2V were successful in that appreciable reductions in grain size were realized. The as-received grain size was 15 {micro}m with a standard deviation of 9.5 {micro}m. For the temperature cycling conditions examined, grain refinement appears to saturate after approximately ten cycles at a grain size of 6 {micro}m with standard deviation of 4 {micro}m. The process also reduces the range of grain sizes present in these samples as the largest grain noted in the as received and treated conditions were 64 and 26 {micro}m, respectively. The results were, however, complicated by the formation of an unexpected secondary ferritic constituent and considerable effort was directed at characterizing this phase. The analysis indicates that the phase is a V-rich ferrite, known as {alpha}{sub 2}, that forms due to an imbalance in the partitioning of vanadium during the heating and cooling portions of the thermal cycle. Considerable but unsuccessful effort was also directed at understanding the conditions under which this phase forms, since it is conceivable that this phase restricts the degree to which the grains can be refined. Due to this difficulty and the relatively short timeframe available in the study, magnetic and mechanical properties of the refined material could not be evaluated. An assessment of the potential for properties improvement through the transformation cycling approach, as well as recommendations for potential future work, are included in this report.

  14. Validating computed grain boundary energies in fcc metals using the grain boundary character distribution

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    Validating computed grain boundary energies in fcc metals using the grain boundary character. Since the GBCD is inversely related to the grain boundary energy distribution, it offers a useful metric for validating grain boundary energy calculations. Comparisons between the measured GBCD and calculated energies

  15. Protein content of grains of different size fractions in malting barley

    E-Print Network [OSTI]

    Nacional de San Luis, Universidad

    of the variation observed in protein content was explained by the ratio of nitrogen availability to grain yield content is not due to the presence of a high proportion of thin grains, because thin grains do not always requirements, barley grain must have a specific protein level and high grain size (i.e. a high proportion

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

    E-Print Network [OSTI]

    Dozier, Jeff

    Retrieval of subpixel snow covered area, grain size, and albedo from MODIS Thomas H. Painter a Keywords: Snow Grain size Albedo Spectral mixture analysis MODIS We describe and validate a model that retrieves fractional snow-covered area and the grain size and albedo of that snow from surface reflectance

  17. A Hyperspectral Method for Remotely Sensing the Grain Size of Snow

    E-Print Network [OSTI]

    Kurapov, Alexander

    A Hyperspectral Method for Remotely Sensing the Grain Size of Snow Anne W. Nolin* and Jeff Dozier in the snowpack. Changes in snow grain size can help identifynique for estimating the grain size in a snowpack's surface ice sheet surface features, such as melt areas, snow dunes,layer from imaging spectrometer data

  18. Determination of the total grain size distributionin a vulcanian eruption column, and its implications to stratospheric aerosol perturbation

    SciTech Connect (OSTI)

    Murrow, P.J.; Rose, W.I. Jr.; Self, S.

    1980-11-01

    Grain size analysis of samples representing all sampleable portions of the airfall deposit produced by the Fuego volcano in Guatemala on 14 October 1974 form the basis for estimating the total grain size distribution of tephra from this eruption. The region enclosed by each isopach has a particular average grain size distribution which can be weighted proportionally to its percentage volume. The grain size of pyroclastic avalanche deposits produced during the eruption are also included. The total grain size distribution calculated as a sum of weighted distributions has a median grain size of 0.80 (0.6mm) and a sorting coefficient (sigma0) of 2.3. The size distribution seems to approximate Rosin and Rammler's law of crushing and this observation allows us to estimate that no more than 15% volume of the fine tail of the total size distribution is likely to be missing. The ash composed of these fine particles did not fall in the region of the volcano as part of the recognizable tephra blanket. The eruption column reached well into the stratosphere: heights estimated from the ground were 10 to 12 km above sea level but estimated heights based on mass flux rates are higher (18 to 23 km). The proportion of ash smaller than 2 ..mu..m, which could remain for substantial periods in the stratosphere, is no more than 0.8% volume of the total. It seems probable that acid aerosol particles from vulcanian type eruptions are more important to stratospheric aerosol perturbation than fine silicate ash particles by at least an order of magnitude.

  19. Disk radii and grain sizes in Herschel-resolved debris disks

    SciTech Connect (OSTI)

    Pawellek, Nicole; Krivov, Alexander V. [Astrophysikalisches Institut und Universitätssternwarte, Friedrich-Schiller-Universität Jena, Schillergäßchen 2-3, 07745 Jena (Germany); Marshall, Jonathan P. [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia); Montesinos, Benjamin [Departmento de Astrofísica, Centro de Astrobiología (CAB, CSIC-INTA), ESAC Campus, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Ábrahám, Péter; Moór, Attila [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, P.O. Box 67, H-1525 Budapest (Hungary); Bryden, Geoffrey [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Eiroa, Carlos [Departamento de Física Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain)

    2014-09-01

    The radii of debris disks and the sizes of their dust grains are important tracers of the planetesimal formation mechanisms and physical processes operating in these systems. Here we use a representative sample of 34 debris disks resolved in various Herschel Space Observatory (Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA) programs to constrain the disk radii and the size distribution of their dust. While we modeled disks with both warm and cold components, and identified warm inner disks around about two-thirds of the stars, we focus our analysis only on the cold outer disks, i.e., Kuiper-belt analogs. We derive the disk radii from the resolved images and find a large dispersion for host stars of any spectral class, but no significant trend with the stellar luminosity. This argues against ice lines as a dominant player in setting the debris disk sizes, since the ice line location varies with the luminosity of the central star. Fixing the disk radii to those inferred from the resolved images, we model the spectral energy distribution to determine the dust temperature and the grain size distribution for each target. While the dust temperature systematically increases toward earlier spectral types, the ratio of the dust temperature to the blackbody temperature at the disk radius decreases with the stellar luminosity. This is explained by a clear trend of typical sizes increasing toward more luminous stars. The typical grain sizes are compared to the radiation pressure blowout limit s {sub blow} that is proportional to the stellar luminosity-to-mass ratio and thus also increases toward earlier spectral classes. The grain sizes in the disks of G- to A-stars are inferred to be several times s {sub blow} at all stellar luminosities, in agreement with collisional models of debris disks. The sizes, measured in the units of s {sub blow}, appear to decrease with the luminosity, which may be suggestive of the disk's stirring level increasing toward earlier-type stars. The dust opacity index ? ranges between zero and two, and the size distribution index q varies between three and five for all the disks in the sample.

  20. LUNAR DUST GRAIN CHARGING BY ELECTRON IMPACT: DEPENDENCE OF THE SURFACE POTENTIAL ON THE GRAIN SIZE

    SciTech Connect (OSTI)

    Nemecek, Z.; Pavlu, J.; Safrankova, J.; Beranek, M.; Richterova, I.; Vaverka, J.; Mann, I.

    2011-09-01

    The secondary electron emission is believed to play an important role for the dust charging at and close to the lunar surface. However, our knowledge of emission properties of the dust results from model calculations and rather rare laboratory investigations. The present paper reports laboratory measurements of the surface potential on Lunar Highlands Type regolith simulants with sizes between 0.3 and 3 {mu}m in an electron beam with energy below 700 eV. This investigation is focused on a low-energy part, i.e., {<=}100 eV. We found that the equilibrium surface potential of this simulant does not depend on the grain size in our ranges of grain dimensions and the beam energies, however, it is a function of the primary electron beam energy. The measurements are confirmed by the results of the simulation model of the secondary emission from the spherical samples. Finally, we compare our results with those obtained in laboratory experiments as well as those inferred from in situ observations.

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

    E-Print Network [OSTI]

    Rohrer, Gregory S.

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

  2. Influence of grain size, shape and compaction on georadar waves: example of an Aeolian dune

    E-Print Network [OSTI]

    Guillemoteau, Julien; Dujardin, Jean-Rémi; 10.1111/j.1365-246X.2012.05577.x

    2012-01-01

    Many Ground Penetrating Radar (GPR) profiles acquired in dry aeolian environment have shown good reflectivity inside present-day dunes. We show that the origin of this reflectivity is related to changes in grain size distribution, packing and/or grain shape in a sandy material. We integrate these three parameters into analytical models for bulk permittivity in order to predict the reflections and the velocity of GPR waves. We consider two GPR cross-sections acquired over Aeolian dunes in the Chadian desert. The 2D migration of GPR data suggests that dunes contain different kinds of bounding surfaces. We discuss and model three kinds of reflections using reasonable geological hypothesis about Aeolian sedimentation processes. The propagation and the reflection of radar waves are calculated using the 1D wavelet modelling method in spectral domain. The results of the forward modelling are in good accordance with real observed data.

  3. Grain size dependent mechanical properties of nanocrystalline diamond films grown by hot-filament CVD

    SciTech Connect (OSTI)

    Wiora, M; Bruehne, K; Floeter, A; Gluche, P; Willey, T M; Kucheyev, S O; Van Buuren, A W; Hamza, A V; Biener, J; Fecht, H

    2008-08-01

    Nanocrystalline diamond (NCD) films with a thickness of {approx}6 {micro}m and with average grain sizes ranging from 60 to 9 nm were deposited on silicon wafers using a hot-filament chemical vapor deposition (HFCVD) process. These samples were then characterized with the goal to identify correlations between grain size, chemical composition and mechanical properties. The characterization reveals that our films are phase pure and exhibit a relatively smooth surface morphology. The levels of sp{sup 2}-bonded carbon and hydrogen impurities are low, and showed a systematic variation with the grain size. The hydrogen content increases with decreasing grain size, whereas the sp{sup 2} carbon content decreases with decreasing grain size. The material is weaker than single crystalline diamond, and both stiffness and hardness decrease with decreasing grain size. These trends suggest gradual changes of the nature of the grain boundaries, from graphitic in the case of the 60 nm grain size material to hydrogen terminated sp{sup 3} carbon for the 9 nm grain size material. The films exhibit low levels of internal stress and freestanding structures with a length of several centimeters could be fabricated without noticeable bending.

  4. Ultrafine-grain-sized zirconium by dynamic deformation , J.-M. Gebert b

    E-Print Network [OSTI]

    Meyers, Marc A.

    Ultrafine-grain-sized zirconium by dynamic deformation B.K. Kad a , J.-M. Gebert b , M.T. Perez A polycrystalline zirconium alloy (Zircadine 702, containing 0.7% Hf) was subjected to high plastic strains (shear deformation; Zirconium; Dynamic deformation 1. Introduction Polycrystalline metals with grain sizes

  5. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Comments?govInstrumentsnoaacrnBarrow, Alaska Outreach Home Roomparticle sizefraction ARMGeometry ARM DataSize

  6. Effect of particles attachment to multi-sized dust grains present in electrostatic sheaths of discharge plasmas

    SciTech Connect (OSTI)

    Zaham, B.; Tahraoui, A. Chekour, S.; Benlemdjaldi, D.

    2014-12-15

    The loss of electrons and ions due to their attachment to a Gauss-distributed sizes of dust grains present in electrostatic sheaths of discharge plasmas is investigated. A uni-dimensional, unmagnetized, and stationary multi-fluid model is proposed. Forces acting on the dust grain along with its charge are self-consistently calculated, within the limits of the orbit motion limited model. The dynamic analysis of dust grains shows that the contribution of the neutral drag force in the net force acting on the dust grain is negligible, whereas the contribution of the gravity force is found considerable only for micrometer particles. The dust grains trapping is only possible when the electrostatic force is balanced by the ion drag and the gravity forces. This trapping occurs for a limited radius interval of micrometer dust grains, which is around the most probable dust grain radius. The effect of electron temperature and ion density at the sheath edge is also discussed. It is shown that the attachment of particles reduces considerably the sheath thickness and induces dust grain deceleration. The increase of the lower limit as well as the upper limit of the dust radius reduces also the sheath thickness.

  7. Particle Size Distribution of Gypseous Samples 

    E-Print Network [OSTI]

    Arnett, Morgan P.

    2010-01-16

    Particle size distribution (PSD) of gypseous soils is important in the soil science community. When gypsum constitutes a major portion of the soil, its removal prior to PSD analysis distorts the results and may lead to ...

  8. Dust Dynamics in Protoplanetary Disk Winds Driven by Magneto-Rotational Turbulence: A Mechanism for Floating Dust Grains with Characteristic Size

    E-Print Network [OSTI]

    Miyake, Tomoya; Inutsuka, Shu-ichiro

    2015-01-01

    We investigate the dynamics of dust grains with various sizes in protoplanetary disk winds driven by magnetorotational turbulence, by simulating the time evolution of the dust grain distribution in the vertical direction. Small dust grains, which are well coupled to the gas, are dragged upward with the upflowing gas, while large grains remain near the midplane of a disk. Intermediate--size grains float at several scale heights from the midplane in time-averated force balance between the downward gravity and the upward gas drag. For the minimum mass solar nebula at 1 AU, dust grains with size of 20 -- 40 $\\mu m$ float at 5-10 scale heights from the midplane. Considering the dependence on the distance from the central star, smaller-size grains remain only in an outer region of the disk, while larger-size grains are distributed in a broader region. This implies that the dust depletion is expected to take place in small-to-large and inside-out manners. We also discuss the implication of our result to the observat...

  9. Effects of particle size on digestion of sorghum grains 

    E-Print Network [OSTI]

    Walker, Reuben Don

    1972-01-01

    will depend on the supply of sorghum or other feed grains. Its feeding value for ruminants is consistently 92-95/ that of corn, which is reflected in slightly lower gains, increased feed requirements and lower returns for the sorghum based rations. Effic...

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

    E-Print Network [OSTI]

    Garmestani, Hamid

    Abstract Temper cold rolled silicon steel samples were annealed with and without an applied magnetic field. Keywords: Soft magnet; Magnetic annealing; Texture; Grain growth 1. Introduction Silicon steel is a softEffect of magnetic field applied during secondary annealing on texture and grain size of silicon

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

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    Relative grain boundary area and energy distributions in nickel Jia Li, Shen J. Dillon 1 , Gregory crystallographic parameters, a quantity that will be referred to as the grain boundary energy distribution (GBED­20]. The first comprehensive measurement of the grain boundary energy distribution was carried out for Mg

  12. Grain size limits derived from 3.6 {\\mu}m and 4.5 {\\mu}m coreshine

    E-Print Network [OSTI]

    Steinacker, J; Thi, W -F; Paladini, R; Juvela, M; Bacmann, A; Pelkonen, V -M; Pagani, L; Lefèvre, C; Henning, Th; Noriega-Crespo, A

    2015-01-01

    Recently discovered scattered light from molecular cloud cores in the wavelength range 3-5 {\\mu}m (called "coreshine") seems to indicate the presence of grains with sizes above 0.5 {\\mu}m. We aim to analyze 3.6 and 4.5 {\\mu}m coreshine from molecular cloud cores to probe the largest grains in the size distribution. We analyzed dedicated deep Cycle 9 Spitzer IRAC observations in the 3.6 and 4.5 {\\mu}m bands for a sample of 10 low-mass cores. We used a new modeling approach based on a combination of ratios of the two background- and foreground-subtracted surface brightnesses and observed limits of the optical depth. The dust grains were modeled as ice-coated silicate and carbonaceous spheres. We discuss the impact of local radiation fields with a spectral slope differing from what is seen in the DIRBE allsky maps. For the cores L260, ecc806, L1262, L1517A, L1512, and L1544, the model reproduces the data with maximum grain sizes around 0.9, 0.5, 0.65, 1.5, 0.6, and > 1.5 {\\mu}m, respectively. The maximum coreshi...

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

    E-Print Network [OSTI]

    Utrecht, Universiteit

    goethite are recognised by their high (remanent) coercivities. The ratio of saturation remanent with increasing grain size for sizes larger than one micrometer. In contrast, the coercivity of goethite showed of the iron oxides magnetite, titanomagnetite, maghemite and he- matite, the iron oxyhydroxide goethite

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

    E-Print Network [OSTI]

    Ritchie, Robert

    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

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

    SciTech Connect (OSTI)

    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)

    2014-07-28

    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.

  16. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Comments?govInstrumentsnoaacrnBarrow, Alaska Outreach Home Roomparticle size distribution ARM Data Discovery

  17. THE INFLUENCE OF THE GRAIN STRUCTURE SIZE ON MICROSTRUCTURALLY SHORT CRACKS

    E-Print Network [OSTI]

    Cizelj, Leon

    ; crystal plasticity ABSTRACT The dominant processes in the initialization and propagation elasticity and crystal plasticity constitutive models are employed at the grain size scale. It is shown& strain rate tensor p kl& plastic strain rate tensoR crack direction ij stress tensor ij& stress rate

  18. Retrieval of subpixel snow-covered area and grain size from imaging spectrometer data

    E-Print Network [OSTI]

    Dozier, Jeff

    Retrieval of subpixel snow-covered area and grain size from imaging spectrometer data Thomas H 2002 Abstract We describe and validate an automated model that retrieves subpixel snow-covered area multiple endmember spectral mixtures with a spectral library of snow, vegetation, rock, and soil. We derive

  19. The Effect of Grain Size on Spectral Mixture Analysis of Snow-Covered Area from

    E-Print Network [OSTI]

    Dozier, Jeff

    The Effect of Grain Size on Spectral Mixture Analysis of Snow-Covered Area from AVIRIS Data Thomas to improve spectral mixture Results were verified with a high spatial resolution aerial analysis of snow of multiple snow endmembers. Snow reflectance of fraction under/overflow and residuals confirmed mix- in near

  20. Impact of sediment grain-size and biofilm age on epipelic microphytobenthos resuspension

    E-Print Network [OSTI]

    Impact of sediment grain-size and biofilm age on epipelic microphytobenthos resuspension Martin polymeric Substances Sediment Intertidal zones are dynamic areas, where tidal currents and wind-induced waves are responsible of resuspension of the sediment and associated microphytobenthos (MPB). Sediment

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

    E-Print Network [OSTI]

    Laughlin, David E.

    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

  2. A continuum theory of grain size evolution and damage and D. Bercovici2

    E-Print Network [OSTI]

    and coalescence. The continuous and discontinuous processes of grain size variation are prescribed. Damage per se is the generic process for generation of microcracks, defects, dislocations (including standard mass, momentum, and energy conservation, as well as entropy production, on a statistically

  3. Influence of Annealing Treatment on the Formation of Nano/Submicron Grain Size AISI 301 Austenitic

    E-Print Network [OSTI]

    Ferreira, Paulo J.

    austenitic stainless steels are heavily cold-worked, and annealed to convert the deformation of annealing temperature. In this work, an AISI 301 metastable austenitic stainless steel is 90 pct coldInfluence of Annealing Treatment on the Formation of Nano/Submicron Grain Size AISI 301 Austenitic

  4. 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)

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

    2012-10-01

    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 2100°C) 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.

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

    DOE Patents [OSTI]

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

    2006-10-31

    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.

  6. Flow rate of polygonal grains through a bottleneck: Interplay between shape and size

    E-Print Network [OSTI]

    Ezequiel Goldberg; C. Manuel Carlevaro; Luis A. Pugnaloni

    2015-05-21

    We report two-dimensional simulations of circular and polygonal grains passing through an aperture at the bottom of a silo. The mass flow rate for regular polygons is lower than for disks as observed by other authors. We show that both the exit velocity of the grains and the packing fraction are lower for polygons, which leads to the reduced flow rate. We point out the importance of the criteria used to define when two objects of different shape are considered to be of the same size. Depending on this criteria, the mass flow rate may vary significantly for some polygons. Moreover, the particle flow rate is non-trivially related to a combination of mass flow rate, particle shape and particle size. For some polygons, the particle flow rate may be lower or higher than that of the corresponding disks depending on the size comparison criteria.

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

    E-Print Network [OSTI]

    Venditti, Jeremy G.

    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

  8. Intrinsic and Extrinsic Size Effects in Fine-Grained Morphotropic-Phase-Boundary Lead Zirconate Titanate Ceramics

    E-Print Network [OSTI]

    Cao, Wenwu

    Titanate Ceramics Clive A. Randall,* Namchul Kim, John-Paul Kucera,* Wenwu Cao, and Thomas R. Shrout The processing, electromechanical properties, and micro- structure of lead zirconate titanate (PZT) ceramics over the influence of grain size on the piezoelectric properties in PZT ceramics. In general, grain-size studies were

  9. Parameterizing Size Distribution in Ice Clouds

    SciTech Connect (OSTI)

    DeSlover, Daniel; Mitchell, David L.

    2009-09-25

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

  10. Pore size distribution and accessible pore size distribution in bituminous coals

    SciTech Connect (OSTI)

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

    2012-01-01

    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.

  11. Characterization of the Grain-Boundary Character and Energy Distributions of Yttria Using Automated Serial Sectioning and

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    Characterization of the Grain-Boundary Character and Energy Distributions of Yttria Using Automated (GBCD) and grain-boundary energy distribution (GBED). The GBCD de- rived from the three-dimensional data- entation parameters.10 In parallel with the GBCD, one can define the grain-boundary energy distribution

  12. The five-parameter grain boundary character and energy distributions of a fully austenitic high-manganese steel using

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    The five-parameter grain boundary character and energy distributions of a fully austenitic high sectioning. The relative grain boundary area and energy distributions were strongly influenced by both structure (e.g. face- centered cubic) have very similar grain boundary character and energy distributions. Ó

  13. 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. Probing the Physical Conditions of Supernova Ejecta with the Measured Sizes of Presolar Al2O3 Grains

    E-Print Network [OSTI]

    Nozawa, Takaya; Hasegawa, Yasuhiro; Kozasa, Takashi

    2015-01-01

    A few particles of presolar Al2O3 grains with sizes above 0.5 mum are believed to have been produced in the ejecta of core-collapse supernovae (SNe). In order to clarify the formation condition of such large Al2O3 grains, we investigate the condensation of Al2O3 grains for wide ranges of the gas density and cooling rate. We first show that the average radius and condensation efficiency of newly formed Al2O3 grains are successfully described by a non-dimensional quantity "Lambda_on" defined as the ratio of the timescale with which the supersaturation ratio increases to the collision timescale of reactant gas species at dust formation. Then, we find that the formation of submicron-sized Al2O3 grains requires at least ten times higher gas densities than those presented by one-dimensional SN models. This indicates that presolar Al2O3 grains identified as a SN origin might be formed in dense gas clumps, allowing us to propose that the measured sizes of presolar grains can be a powerful tool to constrain the physic...

  15. THE COLLISIONAL DIVOT IN THE KUIPER BELT SIZE DISTRIBUTION

    SciTech Connect (OSTI)

    Fraser, Wesley C. [Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, 1200 E. California Blvd. Pasadena, CA 91125 (United States)

    2009-11-20

    This paper presents the results of collisional evolution calculations for the Kuiper Belt starting from an initial size distribution similar to that produced by accretion simulations of that region-a steep power-law large object size distribution that breaks to a shallower slope at r approx 1-2 km, with collisional equilibrium achieved for objects r approx< 0.5 km. We find that the break from the steep large object power law causes a divot, or depletion of objects at r approx 10-20 km, which, in turn, greatly reduces the disruption rate of objects with r approx> 25-50 km, preserving the steep power-law behavior for objects at this size. Our calculations demonstrate that the roll-over observed in the Kuiper Belt size distribution is naturally explained as an edge of a divot in the size distribution; the radius at which the size distribution transitions away from the power law, and the shape of the divot from our simulations are consistent with the size of the observed roll-over, and size distribution for smaller bodies. Both the kink radius and the radius of the divot center depend on the strength scaling law in the gravity regime for Kuiper Belt objects. These simulations suggest that the sky density of r approx 1 km objects is approx10{sup 6}-10{sup 7} objects per square degree. A detection of the divot in the size distribution would provide a measure of the strength of large Kuiper Belt objects, and constrain the shape of the size distribution at the end of accretion in the Kuiper Belt.

  16. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Comments?govInstrumentsnoaacrnBarrow, Alaska Outreach Home Roomparticle sizefraction ARM Datasize distribution ARM

  17. Pore-size-distribution of cationic polyacrylamide hydrogels. Progress report

    SciTech Connect (OSTI)

    Kremer, M.; Prausnitz, J.M.

    1992-06-01

    The pore size distribution of a AAm/MAPTAC (acrylamide copolymerized with (3-methacrylamidopropyl)trimethylammonium chloride) hydrogel was investigated using Kuga`s mixed-solute-exclusion method, taking into account the wall effect. A Brownian-motion model is also used. Results show the feasibility of determining pore-size distribution of porous materials using the mixed-solute-exclusion method in conjunction with solution of the Fredholm equation; good agreement was obtained with experiment, even for bimodal pore structures. However, different pore size distributions were calculated for the two different probe-solutes (Dextran and poly(ethylene glycol/oxide)). Future work is outlined. 32 figs, 25 refs.

  18. Pore-size-distribution of cationic polyacrylamide hydrogels

    SciTech Connect (OSTI)

    Kremer, M.; Prausnitz, J.M.

    1992-06-01

    The pore size distribution of a AAm/MAPTAC (acrylamide copolymerized with (3-methacrylamidopropyl)trimethylammonium chloride) hydrogel was investigated using Kuga's mixed-solute-exclusion method, taking into account the wall effect. A Brownian-motion model is also used. Results show the feasibility of determining pore-size distribution of porous materials using the mixed-solute-exclusion method in conjunction with solution of the Fredholm equation; good agreement was obtained with experiment, even for bimodal pore structures. However, different pore size distributions were calculated for the two different probe-solutes (Dextran and poly(ethylene glycol/oxide)). Future work is outlined. 32 figs, 25 refs.

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

    SciTech Connect (OSTI)

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

    2013-08-01

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

  20. SELF-CONSISTENT SIZE AND VELOCITY DISTRIBUTIONS OF COLLISIONAL CASCADES

    SciTech Connect (OSTI)

    Pan, Margaret [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Schlichting, Hilke E., E-mail: mpan@astro.berkeley.edu, E-mail: hilke@ucla.edu [Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095 (United States)

    2012-03-10

    The standard theoretical treatment of collisional cascades derives a steady-state size distribution assuming a single constant velocity dispersion for all bodies regardless of size. Here we relax this assumption and solve self-consistently for the bodies' steady-state size and size-dependent velocity distributions. Specifically, we account for viscous stirring, dynamical friction, and collisional damping of the bodies' random velocities in addition to the mass conservation requirement typically applied to find the size distribution in a steady-state cascade. The resulting size distributions are significantly steeper than those derived without velocity evolution. For example, accounting self-consistently for the velocities can change the standard q = 3.5 power-law index of the Dohnanyi differential size spectrum to an index as large as q = 4. Similarly, for bodies held together by their own gravity, the corresponding power-law index range 2.88 < q < 3.14 of Pan and Sari can steepen to values as large as q = 3.26. Our velocity results allow quantitative predictions of the bodies' scale heights as a function of size. Together with our predictions, observations of the scale heights for different-sized bodies for the Kuiper belt, the asteroid belt, and extrasolar debris disks may constrain the mass and number of large bodies stirring the cascade as well as the colliding bodies' internal strengths.

  1. Speciation and distribution of arsenic and localization of nutrients in rice grains

    SciTech Connect (OSTI)

    Lombi, E.; Scheckel, K.G.; Pallon, J.; Carey, A.M.; Zhu, Y.G.; Meharg, A.A. (EPA); (UCopenhagen); (Aberdeen); (Lund); (Chinese Aca. Sci.)

    2012-09-05

    Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques ({mu}-XANES, {mu}-X-ray fluorescence ({mu}-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III)-thiol complexes. The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains.

  2. Sedimentation of algae: relationships with biomass and size distribution1

    E-Print Network [OSTI]

    Mazumder, Asit

    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

  3. Effects of scattering and dust grain size on the temperature structure of protoplanetary discs: A three-layer approach

    E-Print Network [OSTI]

    Akio K. Inoue; Akinori Oka; Taishi Nakamoto

    2008-12-03

    The temperature in the optically thick interior of protoplanetary discs is essential for the interpretation of millimeter observations of the discs, for the vertical structure of the discs, for models of the disc evolution and the planet formation, and for the chemistry in the discs. Since large icy grains have a large albedo even in the infrared, the effect of scattering of the diffuse radiation in the discs on the interior temperature should be examined. We have performed a series of numerical radiation transfer simulations including isotropic scattering by grains with various typical sizes for the diffuse radiation as well as for the incident stellar radiation. We also have developed an analytic model including isotropic scattering to understand the physics concealed in the numerical results. With the analytic model, we have shown that the standard two-layer approach is valid only for grey opacity (i.e. grain size $\\ga10$ \\micron) even without scattering. A three-layer interpretation is required for grain size $\\la10$ \\micron. When the grain size is 0.1--10 \\micron, the numerical simulations show that isotropic scattering reduces the temperature of the disc interior. This reduction is nicely explained by the analytic three-layer model as a result of the energy loss by scatterings of the incident stellar radiation and of the warm diffuse radiation in the disc atmosphere. For grain size $\\ga10$ \\micron (i.e. grey scattering), the numerical simulations show that isotropic scattering does not affect the interior temperature. This is nicely explained by the analytic two-layer model; the energy loss by scattering in the disc atmosphere is exactly offset by the "green-house effect" due to scattering of the cold diffuse radiation in the interior.

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

    SciTech Connect (OSTI)

    Michael R Tonks; Yongfeng Zhang; Xianming Bai

    2014-06-01

    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.

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

    E-Print Network [OSTI]

    Martin, Alain

    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

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

    E-Print Network [OSTI]

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

    2015-01-01

    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...

  7. Influence of defects distribution and specimen size on fracture initiation

    E-Print Network [OSTI]

    Krivtsov, Anton M.

    Influence of defects distribution and specimen size on fracture initiation Anton M. Krivtsov akrivtsov@bk.ru Abstract An analytical model for the scale dependence of the fracture initiation is suggested. The model is based on the idea that fracture is a stochastic process, for the bigger specimens

  8. Size distribution and structure of Barchan dune fields

    E-Print Network [OSTI]

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

    2011-05-19

    Barchans are isolated mobile dunes often organized in large dune fields. Dune fields seem to present a characteristic dune size and spacing, which suggests a cooperative behavior based on dune interaction. In Duran et al. (2009), we propose that the redistribution of sand by collisions between dunes is a key element for the stability and size selection of barchan dune fields. This approach was based on a mean-field model ignoring the spatial distribution of dune fields. Here, we present a simplified dune field model that includes the spatial evolution of individual dunes as well as their interaction through sand exchange and binary collisions. As a result, the dune field evolves towards a steady state that depends on the boundary conditions. Comparing our results with measurements of Moroccan dune fields, we find that the simulated fields have the same dune size distribution as in real fields but fail to reproduce their homogeneity along the wind direction.

  9. Spectral snow-reflectance models for grain-size and liquid-water fraction in melting snow for the solar-reflected spectrum

    E-Print Network [OSTI]

    Dozier, Jeff

    Spectral snow-reflectance models for grain-size and liquid- water fraction in melting snow.S.A. ABSTRACT. Two spectral snow-reflectance models that account for the effects of grain-size and liquid calculations are used to specify the essential optical properties of snow in the models.Two approaches

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

    SciTech Connect (OSTI)

    Zurek, Anna K; Muszka, K; Majta, J; Wielgus, M

    2009-01-01

    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.

  11. Method for measuring the size distribution of airborne rhinovirus

    SciTech Connect (OSTI)

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

    2002-01-01

    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.

  12. Fluctuating fitness shapes the clone size distribution of immune repertoires

    E-Print Network [OSTI]

    Desponds, Jonathan; Walczak, Aleksandra M

    2015-01-01

    The adaptive immune system relies on the diversity of receptors expressed on the surface of B and T-cells to protect the organism from a vast amount of pathogenic threats. The proliferation and degradation dynamics of different cell types (B cells, T cells, naive, memory) is governed by a variety of antigenic and environmental signals, yet the observed clone sizes follow a universal power law distribution. Guided by this reproducibility we propose effective models of somatic evolution where cell fate depends on an effective fitness. This fitness is determined by growth factors acting either on clones of cells with the same receptor responding to specific antigens, or directly on single cells with no regards for clones. We identify fluctuations in the fitness acting specifically on clones as the essential ingredient leading to the observed distributions. Combining our models with experiments we characterize the scale of fluctuations in antigenic environments and we provide tools to identify the relevant growth...

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

    SciTech Connect (OSTI)

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

    2013-10-15

    Intergranular reheat cracking in the coarse-grained heat-affected zone of T23 steel was produced by strain to fracture tests on a Gleeble 3500 thermal–mechanical 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.

  14. Grain size and texture effect on compression behavior of hot-extruded Mg-3Al-1Zn alloys at room temperature

    SciTech Connect (OSTI)

    Chang, L.L. [Department of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, Y.N., E-mail: wynmm@dlut.edu.cn [Department of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Zhao, X. [Key laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110005 (China); Qi, M. [Department of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)

    2009-09-15

    Hot-extruded AZ31 alloy was subjected to compression at room temperature. The influence of grain size and grain orientation on the compression behavior of the specimens was examined by optical microscopy, compression test and X-ray diffraction. Abundant twins activated during compression of extruded AZ31 magnesium alloy. The hot extruded AZ31 magnesium alloys had a higher Hall-Petch slope for compression than that for tension.

  15. Sifting attacks in finite-size quantum key distribution

    E-Print Network [OSTI]

    Corsin Pfister; Patrick J. Coles; Stephanie Wehner; Norbert Lütkenhaus

    2015-09-02

    A central assumption in quantum key distribution (QKD) is that Eve has no knowledge about which rounds will be used for parameter estimation or key distillation. Here we show that this assumption is violated for iterative sifting, a commonly used sifting procedure that has been em- ployed in both theoretical and experimental finite-size QKD. We show that iterative sifting leads to two problems: (1) some rounds are more likely to be key rounds than others, (2) the public communication of past measurement choices changes this bias round by round. We analyze these two previously unnoticed problems, present eavesdropping strategies that exploit them, and find that the two problems are independent. We propose corrections to the protocol and prove that the resulting protocol, which we call the fixed round number sifting protocol, is secure and can thus replace iterative sifting in future QKD protocols. It outperforms other recently suggested protocols, increasing the efficiency by a factor of almost two. More generally, we present two formal criteria for a sifting protocol which ensure that they are secure. Our criteria may guide the design of future protocols and inspire a more rigorous QKD analysis, which has neglected sifting-related attacks so far.

  16. On the Distribution of Fragment Sizes in the Fragmentation of Polymer Chains.

    E-Print Network [OSTI]

    Hathorn, Bryan C.

    On the Distribution of Fragment Sizes in the Fragmentation of Polymer Chains. B.C. Hathorn, a B of a polymer is calcu­ lated using a simple model based on Transition State Theory to describe the distribution promotes completely random scission, with equal probability distribution for all possible fragment sizes. 1

  17. The size distribution of conspeci c populations: the peoples of New Guinea

    E-Print Network [OSTI]

    The size distribution of conspeci c populations: the peoples of New Guinea Vojtech Novotny1, Department of Biology, Brafova 7, 701 03 Ostrava, Czech Republic The size distribution of the language analogous to the resource division models of species abun- dance distribution in ecological communities

  18. EVOLUTION OF SNOW LINE IN OPTICALLY THICK PROTOPLANETARY DISKS: EFFECTS OF WATER ICE OPACITY AND DUST GRAIN SIZE

    SciTech Connect (OSTI)

    Oka, Akinori; Nakamoto, Taishi; Ida, Shigeru, E-mail: akinorioka1@gmail.com, E-mail: nakamoto@geo.titech.ac.jp [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo (Japan)

    2011-09-10

    Evolution of a snow line in an optically thick protoplanetary disk is investigated with numerical simulations. The ice-condensing region in the disk is obtained by calculating the temperature and the density with the 1+1D approach. The snow line migrates as the mass accretion rate ( M-dot ) in the disk decreases with time. Calculations are carried out from an early phase with high disk accretion rates ( M-dot {approx}10{sup -7} M{sub sun} yr{sup -1}) to a later phase with low disk accretion rates ( M-dot {approx}10{sup -12} M{sub sun} yr{sup -1}) using the same numerical method. It is found that the snow line moves inward for M-dot {approx}>10{sup -10} M{sub sun} yr{sup -1}, while it gradually moves outward in the later evolution phase with M-dot {approx}<10{sup -10} M{sub sun} yr{sup -1}. In addition to the silicate opacity, the ice opacity is taken into consideration. In the inward migration phase, the additional ice opacity increases the distance of the snow line from the central star by a factor of 1.3 for dust grains {approx}< 10 {mu}m in size and of 1.6 for {approx}> 100 {mu}m. It is inevitable that the snow line comes inside Earth's orbit in the course of the disk evolution if the viscosity parameter {alpha} is in the range 0.001-0.1, the dust-to-gas mass ratio is higher than a tenth of the solar abundance value, and the dust grains are smaller than 1 mm. The formation of water-devoid planetesimals in the terrestrial planet region seems to be difficult throughout the disk evolution, which imposes a new challenge to planet formation theory.

  19. Size-dependent polarization distribution in ferroelectric nanostructures: Phase field simulations

    E-Print Network [OSTI]

    Chen, Long-Qing

    to memory and storage devices, sen- sors, and actuators. The properties of low-dimensional ferro- electricsSize-dependent polarization distribution in ferroelectric nanostructures: Phase field simulations distribution in ferroelectric nanostructures embedded in a nonferroelectric medium. The simulation results

  20. The geographic distribution of mammal body size in Europe

    E-Print Network [OSTI]

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

    2006-01-01

    the mammals of Britain and Europe. Houghton Mif?in, Boston.mammals of Britain and Europe. Collins, London. Cotgreave,of mammal body size in Europe Miguel Á. Rodríguez 1 *, Irene

  1. Dust size distribution and concentrations with cottonseed oil mills 

    E-Print Network [OSTI]

    Wiederhold, Lee Roy

    1976-01-01

    -VOLUME SAMPLES FOR P. S. D OF PARTICLES & 100 um DIAMETER (MMD) ANALYSIS OF VARIANCE ON HIGH-VOLUME SAMPLES FOR P. S. D. OF PARTICLES & 100 um DIAMETER (og) MULTIPLE RANGE TEST FOR MEAN VALUES OF MMD BY AREA MULTIPLE RANGE TEST OF MMD BY MILL PARTICLE SIZE... TEST OF AREA DUST CONCENTRATIONS = 15 Pm IN DIAMETER MULTIPLE RANGE TEST OF MILL DUST CONCENTRATIONS & 15 um IN DIAMETER ANALYSIS OF VARIANCE ON PARTICLE SIZING HEAD SAMPLES OF CONCENTRATIONS FOR PARTICLES & 100 IJBI DIAMETER . . . . 47 47 54...

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

    E-Print Network [OSTI]

    Gidley, David

    -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

  3. ENTRAINMENT AND MIXING AND THEIR EFFECTS ON CLOUD DROPLET SIZE DISTRIBUTIONS OF THE STRATOCUMULUS CLOUDS OBSERVED

    E-Print Network [OSTI]

    ENTRAINMENT AND MIXING AND THEIR EFFECTS ON CLOUD DROPLET SIZE DISTRIBUTIONS OF THE STRATOCUMULUS clouds due to entrainment and mixing of the clear air, which then affect the cloud droplet size distribution. How the entrained clear air mixes with cloudy air has been of great interest for the last several

  4. Global Patterns of City Size Distributions and Their Fundamental Drivers

    E-Print Network [OSTI]

    Kerkhoff, Andrew J.

    a global perspective on the problem. If we hope to successfully manage urban environmental impacts, we capita environmental impact of humans varies across settlements of different sizes and across regions¤ *, Andrew J. Kerkhoff2 , Melanie E. Moses3 1 Department of Biology, University of New Mexico, Albuquerque

  5. Statistical distributions of water content and sizes for clouds above Europe

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Statistical distributions of water content and sizes for clouds above Europe R. P. H. Berton O and water content (IWC), horizontal and vertical sizes (L and H), and top temperatures (T) of clouds above and water contents) controlling radiation transfer in the cloud, and geo- metrical sizes used

  6. Lattice model for kinetics and grain-size distribution in crystallization Mario Castro*

    E-Print Network [OSTI]

    Sánchez, Angel "Anxo"

    deposition has been driven by the technological development of active matrix addressed flat-panel displays1 and thin-film solar cells.2 With these and similar applications in mind, the capability to en- gineer that in crystal- lization of Si over SiO2 substrates, nucleation develops in the Si/SiO2 interface due

  7. Size distribution of particle systems analyzed with organic photodetectors

    E-Print Network [OSTI]

    Sentis, Matthias

    2015-01-01

    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...

  8. Distribution Network Design: Selection and Sizing of Congested Connections

    E-Print Network [OSTI]

    Nagi, Rakesh

    promotions (i.e., seasonal) and regular demand. In response to this, at the strategic or aggregate level demand. Several multinational companies use distribution center networks in this manner. For example. For most fast moving consumer goods, demand patterns are quite erratic, being a function of both sales

  9. A solvable model of fracture with power-law distribution of fragment sizes

    E-Print Network [OSTI]

    Ken Yamamoto; Yoshihiro Yamazaki

    2011-06-08

    The present paper describes a stochastic model of fracture, whose fragment size distribution can be calculated analytically as a power-law-like distribution. The model is basically cascade fracture, but incorporates the effect that each fragment in each stage of cascade ceases fracture with a certain probability. When the probability is constant, the exponent of the power-law cumulative distribution lies between -1 and 0, depending not only on the probability but the distribution of fracture points. Whereas, when the probability depends on the size of a fragment, the exponent is less than -1, irrespective of the distribution of fracture points.

  10. The dune size distribution and scaling relations of barchan dune fields

    E-Print Network [OSTI]

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

    2008-10-27

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

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

    DOE Patents [OSTI]

    Dooley, James H; Lanning, David N

    2014-05-27

    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.

  12. Abnormal grain growth in AISI 304L stainless steel

    SciTech Connect (OSTI)

    Shirdel, M.; Mirzadeh, H.; Parsa, M.H.

    2014-11-15

    The microstructural evolution during abnormal grain growth (secondary recrystallization) in 304L stainless steel was studied in a wide range of annealing temperatures and times. At relatively low temperatures, the grain growth mode was identified as normal. However, at homologous temperatures between 0.65 (850 °C) and 0.7 (900 °C), the observed transition in grain growth mode from normal to abnormal, which was also evident from the bimodality in grain size distribution histograms, was detected to be caused by the dissolution/coarsening of carbides. The microstructural features such as dispersed carbides were characterized by optical metallography, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, and microhardness. Continued annealing to a long time led to the completion of secondary recrystallization and the subsequent reappearance of normal growth mode. Another instance of abnormal grain growth was observed at homologous temperatures higher than 0.8, which may be attributed to the grain boundary faceting/defaceting phenomenon. It was also found that when the size of abnormal grains reached a critical value, their size will not change too much and the grain growth behavior becomes practically stagnant. - Highlights: • Abnormal grain growth (secondary recrystallization) in AISI 304L stainless steel • Exaggerated grain growth due to dissolution/coarsening of carbides • The enrichment of carbide particles by titanium • Abnormal grain growth due to grain boundary faceting at very high temperatures • The stagnancy of abnormal grain growth by annealing beyond a critical time.

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

    SciTech Connect (OSTI)

    Sheppard, Scott S.; Trujillo, Chadwick A.

    2010-11-10

    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.

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

    E-Print Network [OSTI]

    Lyn, Gregory Michael

    1994-01-01

    an apparatus has been designed and constructed. A laser diffraction particle analyzer technique is used to spatially measure the spray Sauter-Mean Diameters. The Rosin-Rammler two parameter model is assumed for the droplet size distribution. Injection pressure...

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

    E-Print Network [OSTI]

    Dhar, Prajnaparamita

    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 ...

  16. A predictive model for particle size distribution and yield for Bayer precipitation and classification 

    E-Print Network [OSTI]

    Kapraun, Christopher Michael

    1996-01-01

    This project implements a dynamic alumina hydrate continuous precipitation and classification model in an alumina refining operation to allow the forecasting of a number of relevant process parameters, such as the particle size distribution...

  17. Network Stability under Alpha Fair Bandwidth Allocation with General File Size Distribution

    E-Print Network [OSTI]

    fair bandwidth allocation, with any positive alpha parameter, a Lyapunov function is constructed1 Network Stability under Alpha Fair Bandwidth Allocation with General File Size Distribution. Cornell University, Ithaca, NY. Swinburne University of Technology, Australia. Abstract--Rate allocation

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

    E-Print Network [OSTI]

    Bauer, Herman John

    1963-01-01

    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...

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

    DOE Patents [OSTI]

    Dooley, James H; Lanning, David N

    2013-07-30

    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.

  20. ON CENTRIFUGAL SETTLING OF POLYDISPERSE SUSPENSIONS WITH A CONTINUOUS PARTICLE SIZE DISTRIBUTION

    E-Print Network [OSTI]

    Bürger, Raimund

    ON CENTRIFUGAL SETTLING OF POLYDISPERSE SUSPENSIONS WITH A CONTINUOUS PARTICLE SIZE DISTRIBUTION@ucn.cl ABSTRACT Gravity or centrifugal sedimentation of polydisperse suspensions with a continuous particle size is extended to settling in a rotating tube or basket centrifuge. Numerical simulations are presented

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

    DOE Patents [OSTI]

    Dooley, James H; Lanning, David N

    2013-08-13

    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.

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

    SciTech Connect (OSTI)

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

    2013-02-10

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

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

    SciTech Connect (OSTI)

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

    2011-11-01

    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.

  4. Analysis of Dispersive and Distributive Mixing In Terms of Minor Component Size and Spatial Distributions

    E-Print Network [OSTI]

    Distributions In Continuous Polymer Processing Equipment Winston Wang and Ica Manas-Zloczower Department polymer processing opera- tions. Material processability and product properties are highly influenced of the minor component enhances sys- tem homogeneity. In continuous mixing processes, composition uniformity

  5. Ultrashort laser ablation of bulk copper targets: Dynamics and size distribution of the generated nanoparticles

    SciTech Connect (OSTI)

    Tsakiris, N.; Gill-Comeau, M.; Lewis, L. J.; Anoop, K. K.; Ausanio, G.; Bruzzese, R.; Amoruso, S.

    2014-06-28

    We address the role of laser pulse fluence on expansion dynamics and size distribution of the nanoparticles produced by irradiating a metallic target with an ultrashort laser pulse in a vacuum, an issue for which contrasting indications are present in the literature. To this end, we have carried out a combined theoretical and experimental analysis of laser ablation of a bulk copper target with ?50 fs, 800?nm pulses, in an interval of laser fluencies going from few to several times the ablation threshold. On one side, molecular dynamics simulations, with two-temperature model, describe the decomposition of the material through the analysis of the evolution of thermodynamic trajectories in the material phase diagram, and allow estimating the size distribution of the generated nano-aggregates. On the other side, atomic force microscopy of less than one layer nanoparticles deposits on witness plates, and fast imaging of the nanoparticles broadband optical emission provide the corresponding experimental characterization. Both experimental and numerical findings agree on a size distribution characterized by a significant fraction (?90%) of small nanoparticles, and a residual part (?10%) spanning over a rather large size interval, evidencing a weak dependence of the nanoparticles sizes on the laser pulse fluence. Numerical and experimental findings show a good degree of consistency, thus suggesting that modeling can realistically support the search for experimental methods leading to an improved control over the generation of nanoparticles by ultrashort laser ablation.

  6. PublishedbyManeyPublishing(c)IOMCommunicationsLtd Size distribution of oxides and toughness of

    E-Print Network [OSTI]

    Cambridge, University of

    the size distribution of oxide particles in steel weld metals which have predominantly martensitic of steel weld metals S. Terashima* and H. K. D. H. Bhadeshia Experiments have been conducted to modify microstruc- tures dominated by low carbon martensite. The role of oxide particles introduced into the metal

  7. On the Size-Dependence of the Inclination Distribution of the Main Kuiper Belt

    E-Print Network [OSTI]

    Levison, Harold F.

    On the Size-Dependence of the Inclination Distribution of the Main Kuiper Belt Harold F. Levison We present a new analysis of the currently available orbital elements for the known Kuiper belt objects. In the non-resonant, main Kuiper belt we #12;nd a statistically signi#12;cant relationship

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

    E-Print Network [OSTI]

    Stanier, Charlie

    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

  9. EVIDENCE FOR A COLOR DEPENDENCE IN THE SIZE DISTRIBUTION OF MAIN-BELT ASTEROIDS Paul Wiegert

    E-Print Network [OSTI]

    Wiegert, Paul

    EVIDENCE FOR A COLOR DEPENDENCE IN THE SIZE DISTRIBUTION OF MAIN-BELT ASTEROIDS Paul Wiegert ($1 km) main-belt asteroids with the 3.6 m Canada-France-Hawaii Telescope. We observed in two filters axis, the difference between the filters in the inner belt is found to be somewhat less pronounced than

  10. Multiscale modeling and control of crystal shape and size distributions: accounting for crystal aggregation, evaluation of continuous crystallization systems and run-to-run control

    E-Print Network [OSTI]

    Kwon, Joseph Sangil

    2015-01-01

    and Size Distributions: Accounting for Crystal Aggregation,and Size Distributions: Accounting for Crystal Aggregation,steady-state growth rate accounting for the dependence of

  11. COLOR DEPENDENCE IN THE SIZE DISTRIBUTION OF MAIN BELT ASTEROIDS REVISITED

    SciTech Connect (OSTI)

    August, Tyler M.; Wiegert, Paul A.

    2013-06-15

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

  12. Evidence for a colour dependence in the size distribution of main belt asteroids

    E-Print Network [OSTI]

    Paul Wiegert; David Balam; Andrea Moss; Christian Veillet; Martin Connors; Ian Shelton

    2006-11-09

    We present the results of a project to detect small (~1 km) main-belt asteroids with the 3.6 meter Canada-France-Hawaii Telescope (CFHT). We observed in 2 filters (MegaPrime g' and r') in order to compare the results in each band. Owing to the observational cadence we did not observe the same asteroids through each filter and thus do not have true colour information. However strong differences in the size distributions as seen in the two filters point to a colour-dependence at these sizes, perhaps to be expected in this regime where asteroid cohesiveness begins to be dominated by physical strength and composition rather than by gravity. The best fit slopes of the cumulative size distributions (CSDs) in both filters tend towards lower values for smaller asteroids, consistent with the results of previous studies. In addition to this trend, the size distributions seen in the two filters are distinctly different, with steeper slopes in r' than in g'. Breaking our sample up according to semimajor axis, the difference between the filters in the inner belt is found to be somewhat less pronounced than in the middle and outer belt, but the CSD of those asteroids seen in the r' filter is consistently and significantly steeper than in g' throughout. The CSD slopes also show variations with semimajor axis within a given filter, particularly in r'. We conclude that the size distribution of main belt asteroids is likely to be colour dependent at kilometer sizes and that this dependence may vary across the belt.

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

    SciTech Connect (OSTI)

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

    2001-01-01

    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.

  14. Ultrahigh throughput plasma processing of free standing silicon nanocrystals with lognormal size distribution

    SciTech Connect (OSTI)

    Dogan, Ilker; Kramer, Nicolaas J.; Westermann, Rene H. J.; Verheijen, Marcel A. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Dohnalova, Katerina; Gregorkiewicz, Tom [Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Smets, Arno H. M. [Photovoltaic Materials and Devices Laboratory, Delft University of Technology, P.O. Box 5031, 2600 GA Delft (Netherlands); Sanden, Mauritius C. M. van de [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Dutch Institute for Fundamental Energy Research (DIFFER), P.O. Box 1207, 3430 BE Nieuwegein (Netherlands)

    2013-04-07

    We demonstrate a method for synthesizing free standing silicon nanocrystals in an argon/silane gas mixture by using a remote expanding thermal plasma. Transmission electron microscopy and Raman spectroscopy measurements reveal that the distribution has a bimodal shape consisting of two distinct groups of small and large silicon nanocrystals with sizes in the range 2-10 nm and 50-120 nm, respectively. We also observe that both size distributions are lognormal which is linked with the growth time and transport of nanocrystals in the plasma. Average size control is achieved by tuning the silane flow injected into the vessel. Analyses on morphological features show that nanocrystals are monocrystalline and spherically shaped. These results imply that formation of silicon nanocrystals is based on nucleation, i.e., these large nanocrystals are not the result of coalescence of small nanocrystals. Photoluminescence measurements show that silicon nanocrystals exhibit a broad emission in the visible region peaked at 725 nm. Nanocrystals are produced with ultrahigh throughput of about 100 mg/min and have state of the art properties, such as controlled size distribution, easy handling, and room temperature visible photoluminescence.

  15. Size and spacial distribution of micropores in SBA-15 using CM-SANS

    SciTech Connect (OSTI)

    Pollock, Rachel A; Walsh, Brenna R; Fry, Jason A; Ghampson, Tyrone; Centikol, Ozgul; Melnichenko, Yuri B; Kaiser, Helmut; Pynn, Roger; Frederick, Brian G

    2011-01-01

    Diffraction intensity analysis of small-angle neutron scattering measurements of dry SBA-15 have been combined with nonlocal density functional theory (NLDFT) analysis of nitrogen desorption isotherms to characterize the micropore, secondary mesopore, and primary mesopore structure. The radial dependence of the scattering length density, which is sensitive to isolated surface hydroxyls, can only be modeled if the NLDFT pore size distribution is distributed relatively uniformly throughout the silica framework, not localized in a 'corona' around the primary mesopores. Contrast matching-small angle neutron scattering (CM-SANS) measurements, using water, decane, tributylamine, cyclohexane, and isooctane as direct probes of the size of micropores indicate that the smallest pores in SBA-15 have diameter between 5.7 and 6.2 {angstrom}. Correlation of the minimum pore size with the onset of the micropore size distribution provides direct evidence that the shape of the smallest micropores is cylinderlike, which is consistent with their being due to unraveling of the polymer template.

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

    E-Print Network [OSTI]

    A. M. Selvam

    2014-08-14

    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.

  17. Supplementary material for "Does the size distribution of mineral dust aerosols depend on the wind speed at emission?"

    E-Print Network [OSTI]

    Meskhidze, Nicholas

    Supplementary material for "Does the size distribution of mineral dust aerosols depend on the wind by truncating those bins. I do so by assuming that the sub-bin distribution follows the power law found by both

  18. The effect of fuel and engine design on diesel exhaust particle size distributions

    SciTech Connect (OSTI)

    Baumgard, K.J.; Johnson, J.H. [Michigan Technological Univ., Houghton, MI (United States)

    1996-09-01

    The objective of this research was to obtain diesel particle size distributions from a 1988 and a 1991 diesel engine using three different fuels and two exhaust control technologies (a ceramic particle trap and an oxidation catalytic converter). The particle size distributions from both engines were used to develop models to estimate the composition of the individual size particles. Nucleation theory of the H{sub 2}O and H{sub 2}SO{sub 4} vapor is used to predict when nuclei-mode particles will form in the dilution tunnel. Combining the theory with the experimental data, the conditions necessary in the dilution tunnel for particle formation are predicted. The paper also contains a discussion on the differences between the 1988 and 1991 engine`s particle size distributions. The results indicated that nuclei mode particles (0.0075--0.046 {micro}m) are formed in the dilution tunnel and consist of more than 80% H{sub 2}O-H{sub 2}SO{sub 4} particles when using the 1988 engine and 0.29 wt% sulfur fuel. Nucleation theory indicated that H{sub 2}O-H{sub 2}SO{sub 4} particles may form during dilution at 0.03 wt% fuel sulfur levels and above. The 1991 engine was designed for lower particulate emissions than the 1988 engine and the 1991 engine`s accumulation mode particles (0.046-1.0 {micro}m) were reduced more than 80% by volume compared to the 1988 engine using the same low sulfur fuel. The particle size composition model indicated that using low sulfur fuel and the 1991 engine, the nuclei mode contained more than 45% of the total solid particles and over 85% of the soluble organic fraction.

  19. Crystallographic Characteristics of Grain Boundaries in Dense Yttria-Stabilized Zirconia

    SciTech Connect (OSTI)

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

    2010-04-01

    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.

  20. 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)

    Ahmad, Mohamad M.; Yamada, Koji

    2014-04-21

    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 2–3??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.

  1. Prediction of the Size Distributions of Methanol-Ethanol Clusters Detected in VUV Laser/Time-of-Flight Mass Spectrometry

    E-Print Network [OSTI]

    Goddard III, William A.

    Prediction of the Size Distributions of Methanol-Ethanol Clusters Detected in VUV Laser distributions and geometries of vapor clusters equilibrated with methanol-ethanol (Me-Et) liquid mixtures were distributions of vapor clusters equilibrated with liquids, ranging from neat alcohols1,2 to methanol-ethanol (Me

  2. Platinum nanoparticle during electrochemical hydrogen evolution: Adsorbate distribution, active reaction species, and size effect

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

    Tan, Teck L.; Wang, Lin -Lin; Zhang, Jia; Johnson, Duane D.; Bai, Kewu

    2015-03-13

    For small Pt nanoparticles (NPs), catalytic activity is, as observed, adversely affected by size in the 1–3 nm range. We elucidate, via first-principles-based thermodynamics, the operation H* distribution and cyclic voltammetry (CV) during the hydrogen evolution reaction (HER) across the electrochemical potential, including the underpotential region (U ? 0) that is difficult to assess in experiment. We consider multiple adsorption sites on a 1 nm Pt NP model and show that the characteristic CV peaks from different H* species correspond well to experiment. We next quantify the activity contribution from each H* species to explain the adverse effect of size.more »From the resolved CV peaks at the standard hydrogen electrode potential (U = 0), we first deduce that the active species for the HER are the partially covered (100)-facet bridge sites and the (111)-facet hollow sites. Upon evaluation of the reaction barriers at operation H* distribution and microkinetic modeling of the exchange current, we find that the nearest-neighbor (100)-facet bridge site pairs have the lowest activation energy and contribute to ~75% of the NP activity. Edge bridge sites (fully covered by H*) per se are not active; however, they react with neighboring (100)-facet H* to account for ~18% of the activity, whereas (111)-facet hollow sites contribute little. As a result, extrapolating the relative contributions to larger NPs in which the ratio of facet-to-edge sites increases, we show that the adverse size effect of Pt NP HER activity kicks in for sizes below 2 nm.« less

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

    E-Print Network [OSTI]

    Koh, Wonshill

    2013-02-22

    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...

  4. Science at the interface : grain boundaries in nanocrystalline metals.

    SciTech Connect (OSTI)

    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.

    2009-09-01

    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.

  5. Distribution approximations for the chemical master equation: comparison of the method of moments and the system size expansion

    E-Print Network [OSTI]

    Alexander Andreychenko; Luca Bortolussi; Ramon Grima; Philipp Thomas; Verena Wolf

    2015-09-30

    The stochastic nature of chemical reactions involving randomly fluctuating population sizes has lead to a growing research interest in discrete-state stochastic models and their analysis. A widely-used approach is the description of the temporal evolution of the system in terms of a chemical master equation (CME). In this paper we study two approaches for approximating the underlying probability distributions of the CME. The first approach is based on an integration of the statistical moments and the reconstruction of the distribution based on the maximum entropy principle. The second approach relies on an analytical approximation of the probability distribution of the CME using the system size expansion, considering higher-order terms than the linear noise approximation. We consider gene expression networks with unimodal and multimodal protein distributions to compare the accuracy of the two approaches. We find that both methods provide accurate approximations to the distributions of the CME while having different benefits and limitations in applications.

  6. The opacity of grains in protoplanetary atmospheres

    E-Print Network [OSTI]

    Naor Movshovitz; Morris Podolak

    2007-09-29

    We have computed the size distribution of silicate grains in the outer radiative region of the envelope of a protoplanet evolving according to the scenario of Pollack et al. (1996). Our computation includes grain growth due to Brownian motion and overtake of smaller grains by larger ones. We also include the input of new grains due to the breakup of planetesimals in the atmosphere. We follow the procedure of Podolak (2003), but have speeded it up significantly. This allows us to test the sensitivity of the code to various parameters. We have also made a more careful estimate of the resulting grain opacity. We find that the grain opacity is of the order of $10^{-2}\\ \\mathrm{cm^2 g^{-1}}$ throughout most of the outer radiative zone as Hubickyj et al. (2005) assumed for their low opacity case, but near the outer edge of the envelope, the opacity can increase to $\\sim{1} \\mathrm{cm^2 g^{-1}}$. We discuss the effect of this on the evolution of the models.

  7. Distribution of maximal clique size of the vertices for theoretical small-world networks and real-world networks

    E-Print Network [OSTI]

    Meghanathan, Natarajan

    2015-01-01

    Our primary objective in this paper is to study the distribution of the maximal clique size of the vertices in complex networks. We define the maximal clique size for a vertex as the maximum size of the clique that the vertex is part of and such a clique need not be the maximum size clique for the entire network. We determine the maximal clique size of the vertices using a modified version of a branch-and-bound based exact algorithm that has been originally proposed to determine the maximum size clique for an entire network graph. We then run this algorithm on two categories of complex networks: One category of networks capture the evolution of small-world networks from regular network (according to the wellknown Watts-Strogatz model) and their subsequent evolution to random networks; we show that the distribution of the maximal clique size of the vertices follows a Poisson-style distribution at different stages of the evolution of the small-world network to a random network; on the other hand, the maximal cl...

  8. Relationship between Particle Size Distribution of Low-Rank Pulverized Coal and Power Plant Performance

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

    Ganguli, Rajive; Bandopadhyay, Sukumar

    2012-01-01

    The impact of particle size distribution (PSD) of pulverized, low rank high volatile content Alaska coal on combustion related power plant performance was studied in a series of field scale tests. Performance was gauged through efficiency (ratio of megawatt generated to energy consumed as coal), emissions (SO 2 , NO x , CO), and carbon content of ash (fly ash and bottom ash). The study revealed that the tested coal could be burned at a grind as coarse as 50% passing 76 microns, with no deleterious impact on power generation andmore »emissions. The PSD’s tested in this study were in the range of 41 to 81 percent passing 76 microns. There was negligible correlation between PSD and the followings factors: efficiency, SO 2 , NO x , and CO. Additionally, two tests where stack mercury (Hg) data was collected, did not demonstrate any real difference in Hg emissions with PSD. The results from the field tests positively impacts pulverized coal power plants that burn low rank high volatile content coals (such as Powder River Basin coal). These plants can potentially reduce in-plant load by grinding the coal less (without impacting plant performance on emissions and efficiency) and thereby, increasing their marketability. « less

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

    SciTech Connect (OSTI)

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

    2012-02-01

    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.

  10. Evolution of soot size distribution in premixed ethylene/air and ethylene/benzene/air flames: Experimental and modeling study

    SciTech Connect (OSTI)

    Echavarria, Carlos A.; Sarofim, Adel F.; Lighty, JoAnn S.; D'Anna, Andrea

    2011-01-15

    The effect of benzene concentration in the initial fuel on the evolution of soot size distribution in ethylene/air and ethylene/benzene/air flat flames was characterized by experimental measurements and model predictions of size and number concentration within the flames. Experimentally, a scanning mobility particle sizer was used to allow spatially resolved and online measurements of particle concentration and sizes in the nanometer-size range. The model couples a detailed kinetic scheme with a discrete-sectional approach to follow the transition from gas-phase to nascent particles and their coagulation to larger soot particles. The evolution of soot size distribution (experimental and modeled) in pure ethylene and ethylene flames doped with benzene showed a typical nucleation-sized (since particles do not actually nucleate in the classical sense particle inception is often used in place of nucleation) mode close to the burner surface, and a bimodal behavior at greater height above burner (HAB). However, major features were distinguished between the data sets. The growth of nucleation and agglomeration-sized particles was faster for ethylene/benzene/air flames, evidenced by the earlier presence of bimodality in these flames. The most significant changes in size distribution were attributed to an increase in benzene concentration in the initial fuel. However, these changes were more evident for high temperature flames. In agreement with the experimental data, the model also predicted the decrease of nucleation-sized particles in the postflame region for ethylene flames doped with benzene. This behavior was associated with the decrease of soot precursors after the main oxidation zone of the flames. (author)

  11. Grain Boundary (GB) Studies in Nano- and Micro- Crystalline Materials

    E-Print Network [OSTI]

    Tanju, Mst Sohanazaman

    2011-01-01

    in 2 – 8 % yttria-stabilized zirconia polycrystals? Actain yttria-stabilized cubic zirconia? Philosophical Magazine,grain size, for example zirconia is fully opaque when grain

  12. Method development and validation for measuring the particle size distribution of pentaerythritol tetranitrate (PETN) powders.

    SciTech Connect (OSTI)

    Young, Sharissa Gay

    2005-09-01

    Currently, the critical particle properties of pentaerythritol tetranitrate (PETN) that influence deflagration-to-detonation time in exploding bridge wire detonators (EBW) are not known in sufficient detail to allow development of a predictive failure model. The specific surface area (SSA) of many PETN powders has been measured using both permeametry and gas absorption methods and has been found to have a critical effect on EBW detonator performance. The permeametry measure of SSA is a function of particle shape, packed bed pore geometry, and particle size distribution (PSD). Yet there is a general lack of agreement in PSD measurements between laboratories, raising concerns regarding collaboration and complicating efforts to understand changes in EBW performance related to powder properties. Benchmarking of data between laboratories that routinely perform detailed PSD characterization of powder samples and the determination of the most appropriate method to measure each PETN powder are necessary to discern correlations between performance and powder properties and to collaborate with partnering laboratories. To this end, a comparison was made of the PSD measured by three laboratories using their own standard procedures for light scattering instruments. Three PETN powder samples with different surface areas and particle morphologies were characterized. Differences in bulk PSD data generated by each laboratory were found to result from variations in sonication of the samples during preparation. The effect of this sonication was found to depend on particle morphology of the PETN samples, being deleterious to some PETN samples and advantageous for others in moderation. Discrepancies in the submicron-sized particle characterization data were related to an instrument-specific artifact particular to one laboratory. The type of carrier fluid used by each laboratory to suspend the PETN particles for the light scattering measurement had no consistent effect on the resulting PSD data. Finally, the SSA of the three powders was measured using both permeametry and gas absorption methods, enabling the PSD to be linked to the SSA for these PETN powders. Consistent characterization of other PETN powders can be performed using the appropriate sample-specific preparation method, so that future studies can accurately identify the effect of changes in the PSD on the SSA and ultimately model EBW performance.

  13. Gap-Size Distribution Functions of a Random Sequential Adsorption Model of Segments on the Line

    E-Print Network [OSTI]

    N. A. M. Araujo; A. Cadilhe

    2006-04-24

    We performed extensive simulations accompanied by a detailed study of a two-segment size random sequential model on the line. We followed the kinetics towards the jamming state, but we paid particular attention to the characterization of the jamming state structure. In particular, we studied the effect of the size ratio on the mean-gap size, the gap-size dispersion, gap-size skewness, and gap-size kurtosis at the jamming state. We also analyzed the above quantities for the four possible segment-to-segment gap types. We ranged the values of the size ratio from one to twenty. In the limit of a size ratio of one, one recovers the classical car-parking problem. We observed that at low size ratios the jamming state is constituted by short streaks of small and large segments, while at high values of the size ratio the jamming state structure is formed by long streaks of small segments separated by a single large segment. This view of the jamming state structure as a function of the size ratio is supported by the various measured quantities. The present work can help provide insight, for example, on how to minimize the interparticle distance or minimize fluctuations around the mean particle-to-particle distance.

  14. 20% (AM1.5) efficiency GaAs solar cells on sub-mm grain-size poly-Ge and its transition to low-cost substrates

    SciTech Connect (OSTI)

    Venkatasubramanian, R.; O`Quinn, B.C.; Siivola, E.; Keyes, B.; Ahrenkiel, R.

    1997-12-31

    Some of the key material and device issues related to the development of GaAs solar cells on poly-Ge substrates, including the dark-current reduction mechanism with an undoped spacer at the p{sup +}-n depletion layer, are discussed. Device-structure optimization studies that have led the authors to achieve an AM1.5 efficiency of {approximately}20% for a 4-cm{sup 2}-area GaAs cell on sub-mm grain-size poly-Ge and an efficiency of {approximately}21% for a 0.25-cm{sup 2}-area cell are presented. This successful demonstration of high-efficiency GaAs cells on sub-mm grain-size poly-Ge substrates have motivated us to consider the development of high-quality GaAs materials on significantly lower-cost substrates such as glass and moly foils. To date, the authors have achieved a best minority-carrier lifetime of 0.41 nsec in an n-GaAs thin-film on moly. The role of Group-VI dopant in the possible passivation of grain-boundaries in poly-GaAs is discussed. Development of PV-quality GaAs material, with minority-carrier lifetime of 1 to 2 nsec, on los-cost moly foils can significantly impact both the terrestrial and the space PV applications.

  15. Influence of Cement Particle-Size Distribution on Early Age Autogenous Strains and Stresses in Cement-Based Materials

    E-Print Network [OSTI]

    Bentz, Dale P.

    Influence of Cement Particle-Size Distribution on Early Age Autogenous Strains and Stresses in Cement-Based Materials Dale P. Bentz* Building and Fire Research Laboratory, National Institute-Jochen Haecker* Wilhelm Dyckerhoff Institut, 65203 Wiesbaden, Germany The influence of cement particle

  16. Effect of Particle Optical Properties on Size Distribution of Soils Obtained by Laser Diffraction

    E-Print Network [OSTI]

    Ahmad, Sajjad

    ) is essential infor- mation for those in the fields of engineering and environmental geosciences, sedimentology, sedimentology, pedology, etc. (Wen et al., 2002). In geotechnical practices, PSD and clay-size fraction of soils

  17. Optimal Placement and Sizing of Distributed Generator Units using Genetic Optimization

    E-Print Network [OSTI]

    and electricity in the distribution grid. A group of DG units can form a virtual power plant, being centrally controlled and behaving as a single power plant towards the grid. The extreme case is an energy island to conventional power plants distributed generation units such as PV cells (depending on solar illumination

  18. Environmental Transmission Electron Microscopy Study of the Origins of Anomalous Particle Size Distributions in Supported Metal Catalysts

    SciTech Connect (OSTI)

    Benavidez, Angelica D.; Kovarik, Libor; Genc, Arda; Agrawal, Nitin; Larsson, Elin M.; Hansen, Thomas W.; Karim, Ayman M.; Datye, Abhaya K.

    2012-10-31

    In this Environmental TEM (ETEM) study of supported Pt and Pd model catalysts, individual nanoparticles were tracked during heat treatments at temperatures up to 600°C in H2, O2, and vacuum. We found anomalous growth of nanoparticles occurred during the early stages of catalyst sintering wherein some particles started to grow significantly larger than the mean, resulting in a broadening of the particle size distribution. We can rule out sample non-uniformity as a cause for the growth of these large particles, since images were recorded prior to heat treatments. The anomalous growth of these particles may help explain particle size distributions in heterogeneous catalysts which often show particles that are significantly larger than the mean, resulting in a long tail to the right. It has been suggested that particle migration and coalescence could be the likely cause for the broad size distributions. This study shows that anomalous growth of nanoparticles can occur under conditions where Ostwald ripening is the primary sintering mechanism.

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

    E-Print Network [OSTI]

    McDonnell, Andrew M. P

    2011-01-01

    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 ...

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

    DOE Patents [OSTI]

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

    1982-01-19

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

  1. grain salad

    E-Print Network [OSTI]

    ... shredded 1 medium green apple (tart) 1 medium peach 2 TB fennel seeds - Mix three grains ... I got my fennel seed in the *tea* section of a health food store.

  2. Founding, Foraging, and Fighting: Colony Size and the Spatial Distribution of Harvester Ant Author(s): Deborah M. Gordon and Alan W. Kulig

    E-Print Network [OSTI]

    Gordon, Deborah

    Founding, Foraging, and Fighting: Colony Size and the Spatial Distribution of Harvester Ant Nests of America FOUNDING, FORAGING, AND FIGHTING: COLONY SIZE AND THE SPATIAL DISTRIBUTION OF HARVESTER ANT NESTS meet, most fights are brief, with few resulting in injury or death. These results suggest that the cost

  3. LOAD PROFILING IN DISTRIBUTED REAL-TIME SYSTEMS \\One Size Doesn't Fit All"

    E-Print Network [OSTI]

    pro ling, the system attempts to distribute the load amongst its nodes so as to maximize the chances of nding a node that would satisfy the computational needs of incoming real-time tasks. To that end, we on a solid, analytical foundation for real-time resource management. Examples include the Ada RTSIA

  4. LOAD PROFILING IN DISTRIBUTED REALTIME SYSTEMS \\Lambda ``One Size Doesn't Fit All''

    E-Print Network [OSTI]

    . Using load profiling, the system attempts to distribute the load amongst its nodes so as to maximize the chances of finding a node that would satisfy the computational needs of incoming real­time tasks engineering based on a solid, analytical foundation for real­time resource management. Examples include

  5. Determination of plasma frequency, damping constant, and size distribution from the complex dielectric function of noble metal nanoparticles

    SciTech Connect (OSTI)

    Mendoza Herrera, Luis J.; Arboleda, David Muñetón; Schinca, Daniel C.; Scaffardi, Lucía B.

    2014-12-21

    This paper develops a novel method for simultaneously determining the plasma frequency ?{sub P}?? and the damping constant ?{sub free} in the bulk damped oscillator Drude model, based on experimentally measured real and imaginary parts of the metal refractive index in the IR wavelength range, lifting the usual approximation that restricts frequency values to the UV-deep UV region. Our method was applied to gold, silver, and copper, improving the relative uncertainties in the final values for ?{sub p} (0.5%–1.6%) and for ?{sub free} (3%–8%), which are smaller than those reported in the literature. These small uncertainties in ?{sub p} and ?{sub free} determination yield a much better fit of the experimental complex dielectric function. For the case of nanoparticles (Nps), a series expansion of the Drude expression (which includes ?{sub p} and ?{sub free} determined using our method) enables size-dependent dielectric function to be written as the sum of three terms: the experimental bulk dielectric function plus two size corrective terms, one for free electron, and the other for bound-electron contributions. Finally, size distribution of nanometric and subnanometric gold Nps in colloidal suspension was determined through fitting its experimental optical extinction spectrum using Mie theory based on the previously determined dielectric function. Results are compared with size histogram obtained from Transmission Electron Microscopy (TEM)

  6. Autonomous grain combine control system

    DOE Patents [OSTI]

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

    2013-06-25

    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.

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

    SciTech Connect (OSTI)

    Sukhinin, G. I.; Fedoseev, A. V.

    2007-12-15

    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.

  8. Characterization of secondary grain dust explosions 

    E-Print Network [OSTI]

    Schulman, Cheryl Wendler

    1983-01-01

    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...

  9. Intercomparison of Large-eddy Simulations of Arctic Mixed-phase Clouds: Importance of Ice Size Distribution Assumptions

    SciTech Connect (OSTI)

    Ovchinnikov, Mikhail; Ackerman, Andrew; Avramov, Alex; Cheng, Anning; Fan, Jiwen; Fridlind, Ann; Ghan, Steven J.; Harrington, Jerry Y.; Hoose, Corinna; Korolev, Alexei; McFarquhar, Greg; Morrison, H.; Paukert, Marco; Savre, Julien; Shipway, Ben; Shupe, Matthew D.; Solomon, Amy; Sulia, Kara

    2014-03-14

    Large-eddy simulations of mixed-phase Arctic clouds by 11 different models are analyzed with the goal of improving understanding and model representation of processes controlling the evolution of these clouds. In a case based on observations from the Indirect and Semi-Direct Aerosol Campaign (ISDAC), it is found that ice number concentration, Ni, exerts significant influence on the cloud structure. Increasing Ni leads to a substantial reduction in liquid water path (LWP) and potential cloud dissipation, in agreement with earlier studies. By comparing simulations with the same microphysics coupled to different dynamical cores as well as the same dynamics coupled to different microphysics schemes, it is found that the ice water path (IWP) is mainly controlled by ice microphysics, while the inter-model differences in LWP are largely driven by physics and numerics of the dynamical cores. In contrast to previous intercomparisons, all models here use the same ice particle properties (i.e., mass-size, mass-fall speed, and mass-capacitance relationships) and a common radiation parameterization. The constrained setup exposes the importance of ice particle size distributions (PSD) in influencing cloud evolution. A clear separation in LWP and IWP predicted by models with bin and bulk microphysical treatments is documented and attributed primarily to the assumed shape of ice PSD used in bulk schemes. Compared to the bin schemes that explicitly predict the PSD, schemes assuming exponential ice PSD underestimate ice growth by vapor deposition and overestimate mass-weighted fall speed leading to an underprediction of IWP by a factor of two in the considered case.

  10. Intrinsic fluctuations of dust grain charge in multi-component plasmas

    SciTech Connect (OSTI)

    Shotorban, B.

    2014-03-15

    A master equation is formulated to model the states of the grain charge in a general multi-component plasma, where there are electrons and various kinds of positive or negative ions that are singly or multiply charged. A Fokker-Planck equation is developed from the master equation through the system-size expansion method. The Fokker-Planck equation has a Gaussian solution with a mean and variance governed by two initial-value differential equations involving the rates of the attachment of ions and electrons to the dust grain. Also, a Langevin equation and a discrete stochastic method are developed to model the time variation of the grain charge. Grain charging in a plasma containing electrons, protons, and alpha particles with Maxwellian distributions is considered as an example problem. The Gaussian solution is in very good agreement with the master equation solution numerically obtained for this problem.

  11. How does biomass distribution change with size and differ among species? An analysis for 1200 plant species from five

    E-Print Network [OSTI]

    Minnesota, University of

    Engineering University, Sibirskiy Trakt 37, Ekaterinburg 620100, Russia; 11 Botanical Garden of Ural Branch Resources, University of Minnesota, 1530 Cleveland Ave N, St Paul, MN 55108, USA; 10 Ural State Forest of Russian Academy of Sciences, ul. Vos'mogo Marta 202a, Ekaterinburg 620144, Russia; 12 IA Watson Grains

  12. Grain boundary and triple junction diffusion in nanocrystalline copper

    SciTech Connect (OSTI)

    Wegner, M. Leuthold, J.; Peterlechner, M.; Divinski, S. V.; Song, X.; Wilde, G.

    2014-09-07

    Grain boundary and triple junction diffusion in nanocrystalline Cu samples with grain sizes, ?d?, of ?35 and ?44?nm produced by spark plasma sintering were investigated by the radiotracer method using the {sup 63}Ni isotope. The measured diffusivities, D{sub eff}, are comparable with those determined previously for Ni grain boundary diffusion in well-annealed, high purity, coarse grained, polycrystalline copper, substantiating the absence of a grain size effect on the kinetic properties of grain boundaries in a nanocrystalline material at grain sizes d???35?nm. Simultaneously, the analysis predicts that if triple junction diffusion of Ni in Cu is enhanced with respect to the corresponding grain boundary diffusion rate, it is still less than 500?D{sub gb} within the temperature interval from 420?K to 470?K.

  13. Evaluation of moist processes during intense precipitation in km-scale NWP models using remote sensing and in-situ data: Impact of microphysics size distribution assumptions

    SciTech Connect (OSTI)

    Van Weverberg, K.; van Lipzig, N. P. M.; Delobbe, L.

    2011-02-01

    This study investigates the sensitivity of moist processes and surface precipitation during three extreme precipitation events over Belgium to the representation of rain, snow and hail size distributions in a bulk one-moment microphysics parameterisation scheme. Sensitivities included the use of empirically derived relations to calculate the slope parameter and diagnose the intercept parameter of the exponential snow and rain size distributions and sensitivities to the treatment of hail/graupel. A detailed evaluation of the experiments against various high temporal resolution and spatially distributed observational data was performed to understand how moist processes responded to the implemented size distribution modifications. Net vapor consumption by microphysical processes was found to be unaffected by snow or rain size distribution modifications, while it was reduced replacing formulations for hail by those typical for graupel, mainly due to intense sublimation of graupel. Cloud optical thickness was overestimated in all experiments and all cases, likely due to overestimated snow amounts. The overestimation slightly deteriorated by modifying the rain and snow size distributions due to increased snow depositional growth, while it was reduced by including graupel. The latter was mainly due to enhanced cloud water collection by graupel and reduced snow depositional growth. Radar reflectivity and cloud optical thickness could only be realistically represented by inclusion of graupel during a stratiform case, while hail was found indispensable to simulate the vertical reflectivity profile and the surface precipitation structure. Precipitation amount was not much altered by any of the modifications made and the general overestimation was only decreased slightly during a supercell convective case.

  14. Cement and Concrete Research, Vol. 42 (2), 404-409, 2012. Influence of Particle Size Distributions on Yield Stress and Viscosity of

    E-Print Network [OSTI]

    Bentz, Dale P.

    on Yield Stress and Viscosity of Cement-Fly Ash Pastes Dale P. Bentz Chiara F. Ferraris Michael A. Galler of three variables (cement particle size distribution (PSD), fly ash PSD, and ratio of fly ash to cement of either total (cement + fly ash) particle surface area or total particle density. Keywords: Cement; fly

  15. Investigating the fine grained structure of networks

    E-Print Network [OSTI]

    Macindoe, Owen

    2010-01-01

    In this thesis I explore a novel representation for characterizing a graph's fine grained structure. The key idea is that this structure can be represented as a distribution of the structural features of subgraphs. I ...

  16. 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)

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

    2014-10-01

    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-µm 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.

  17. PRINT ONLY: PRESOLAR GRAINS Fisenko A. V. Semjonova L. F.

    E-Print Network [OSTI]

    Rathbun, Julie A.

    of the Boriskino CM2 Nanodiamond [#1045] The analysis of grain-size fractions of the Boriskino nanodiamond has and Ne contents in nanodiamond are caused by noble gas component. Lunar and Planetary Science XXXVII (2006) full811.pdf #12;HELIUM AND NEON IN GRAIN-SIZE FRACTIONS OF THE BORISKINO CM2 NANODIAMOND. A

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

    SciTech Connect (OSTI)

    Valderrama, Billy [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; He, Lingfeng [Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics; Henderson, Hunter B. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Pakarinen, Janne [Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics; Jaques, Brian [Boise State Univ., Boise, Idaho (United States). Dept. of Materials Science and Engineering; Gan, Jian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Butt, Darryl P. [Boise State Univ., Boise, Idaho (United States). Dept. of Materials Science and Engineering; Allen, Todd R. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics; Idaho National Lab. (INL), Idaho Falls, ID (United States); Manuel, Michele V. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering

    2014-12-01

    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 1000ºC, 1300ºC, and 1600°C 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 UO2 samples.

  19. Measurements of excess enthalpy in ultrafine-grained titanium dioxide

    SciTech Connect (OSTI)

    Terwilliger, C.D.; Chiang, Y.M. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering

    1995-08-01

    Differential scanning calorimetry has been used to make direct measurements of the excess enthalpy of TiO{sub 2} (rutile) with an initial grain size of 30--70 nm. When the heat released during grain growth is normalized to the change in grain boundary area, the specific excess enthalpy at low temperature sn the fine grain sizes (600--780 C, 30--200 nm) is found to be 0.5--1 J/m{sup 2}, while values averaged over a larger temperature and size range (600--1,300 C, 30 nm-{approximately} 2 {micro}m) are 1.3--1.7 J/m{sup 2}. After exclusion of extraneous contributions from other heat-dissipating processes, origins of a specific grain boundary enthalpy that increases with grain size or temperature are considered, including solute segregation, changes in grain boundary structure, and contributions from grain boundary triple junctions. It is concluded that the most plausible explanation is a size-dependent nonstoichiometry of TiO{sub 2} due to the impingement of space charge layers in the temperature and grain size range of the experiments.

  20. The role of precipitation size distributions in km-scale NWP simulations of intense precipitation: Evaluation of cloud properties and surface precipitation

    SciTech Connect (OSTI)

    Van Weverberg K.; Vogelmann A.; van Lipzig, N. P. M.; Delobbec, L.

    2012-04-01

    We investigate the sensitivity of simulated cloud properties and surface precipitation to assumptions regarding the size distributions of the precipitating hydrometeors in a one-moment bulk microphysics scheme. Three sensitivity experiments were applied to two composites of 15 convective and 15 frontal stratiform intense precipitation events observed in a coastal midlatitude region (Belgium), which were evaluated against satellite-retrieved cloud properties and radar-rain-gauge derived surface precipitation. It is found that the cloud optical thickness distribution was well captured by all experiments, although a significant underestimation of cloudiness occurred in the convective composite. The cloud-top-pressure distribution was improved most by more realistic snow size distributions (including a temperature-dependent intercept parameter and non-spherical snow for the calculation of the slope parameter), due to increased snow depositional growth at high altitudes. Surface precipitation was far less sensitive to whether graupel or hail was chosen as the rimed ice species, as compared to previous idealized experiments. This smaller difference in sensitivity could be explained by the stronger updraught velocities and higher freezing levels in the idealized experiments compared to typical coastal midlatitude environmental conditions.

  1. Stabilizing Nanocrystalline Grains in Ceramic-Oxides

    SciTech Connect (OSTI)

    Aidhy, Dilpuneet S; Zhang, Yanwen; Weber, William J

    2013-01-01

    Nanocrystalline ceramic-oxides are prone to grain growth rendering their highly attractive properties practically unusable. Using atomistic simulations ofon ceria as a model material system, we elucidate a framework to design dopant-pinned grain boundaries that prevent this grain growth. While in metallic systems it has been shown that a large mismatch between host and dopant atomic size prevents grain growth, in ceramic-oxides we find that this concept is not applicable. Instead, we find that dopant-oxygen vacancy interaction, i.e., dopant migration energy in the presence of oxygen vacancy, and dopant-oxygen vacancy binding energy are the controlling factors in grain growth. Our prediction agrees with and explains previous experimental observations.

  2. Physica Medica -Vol. XVII, Supplement 1, 2001 Monte Carlo Predictions of DNA Fragment-Size Distributions for

    E-Print Network [OSTI]

    Brenner, David Jonathan

    to low-LET radiation. DSB induction due to track interaction with the DNA volume depends on the radiation us to give biophysically based extrapolations of high-dose DNA fragment-size data to low doses on Space Radiation Research and 11th Annual NASA Space Radiation Health Investigators' Workshop Arona

  3. Journal of Power Sources 135 (2004) 7987 Predicting water and current distributions in a commercial-size PEMFC

    E-Print Network [OSTI]

    Van Zee, John W.

    2004-01-01

    in a commercial-size PEMFC S. Shimpaleea, S. Greenwaya, D. Spucklerb, J.W. Van Zeea, a Department of Chemical have experimentally studied small (10­50 cm2), single cell PEMFC systems to understand the behavior and electro- chemistry of PEMFC. Also, three-dimensional electrochemical models have been used to predict

  4. Dust dynamics and evolution in expanding HII regions. I. Radiative drift of neutral and charged grains

    E-Print Network [OSTI]

    Akimkin, V V; Pavlyuchenkov, Ya N; Wiebe, D S

    2015-01-01

    We consider dust drift under the influence of stellar radiation pressure during the pressure-driven expansion of an HII region using the chemo-dynamical model MARION. Dust size distribution is represented by four dust types: conventional polycyclic aromatic hydrocarbons (PAHs), very small grains (VSGs), big grains (BGs) and also intermediate-sized grains (ISGs), which are larger than VSGs and smaller than BGs. The dust is assumed to move at terminal velocity determined locally from the balance between the radiation pressure and gas drag. As Coulomb drag is an important contribution to the overall gas drag, we evaluate a grain charge evolution within the HII region for each dust type. BGs are effectively swept out of the HII region. The spatial distribution of ISGs within the HII region has a double peak structure, with a smaller inner peak and a higher outer peak. PAHs and VSGs are mostly coupled to the gas. The mean charge of PAHs is close to zero, so they can become neutral from time to time because of char...

  5. Arresting bubble coarsening: A model for stopping grain growth with interfacial elasticity

    E-Print Network [OSTI]

    Anniina Salonen; Cyprien Gay; Armando Maestro; Wiebke Drenckhan; Emmanuelle Rio

    2015-05-22

    Many two-phase materials suffer from grain-growth due to the energy cost which is associated with the interface that separates both phases. While our understanding of the driving forces and the dynamics of grain growth in different materials is well advanced by now, current research efforts address the question of how this process may be slowed down, or, ideally, arrested. We use a model system of two bubbles to explore how the presence of an interfacial elasticity may interfere with the coarsening process and the final grain size distribution. Combining experiments and modelling in the analysis of the evolution of two bubbles, we show that clear relationships can be predicted between the interfacial tension, the interfacial elasticity and the change in bubble polydispersity. Despite its general interest, the presented results have direct implications for our understanding of foam stability.

  6. TABLE DR1. GRAIN SIZE DISTRIBUTIONS AND STATISTICS FOR MODELED HILLSLOPESUPPLIED SEDIMENT* Transect Number Distance Downstream d 10 d 50 d 90 Fraction coarser than in each sieve size

    E-Print Network [OSTI]

    Singer, Michael

    .00 27 13231.00 0.89 32.94 61.49 12.12 12.12 0.00 0.00 7.55 16.35 44.42 7.21 0.23 0.00 28 13845.00 0

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

    E-Print Network [OSTI]

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

    2007-09-25

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

  8. Grain Refinement of Permanent Mold Cast Copper Base Alloys

    SciTech Connect (OSTI)

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

    2005-04-01

    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.

  9. Pre-accretional sorting of grains in the outer solar nebula

    SciTech Connect (OSTI)

    Wozniakiewicz, P. J.; Bradley, J. P.; Ishii, H. A.; Price, M. C.; Brownlee, D. E.

    2013-12-20

    Despite their micrometer-scale dimensions and nanogram masses, chondritic porous interplanetary dust particles (CP IDPs) are an important class of extraterrestrial material since their properties are consistent with a cometary origin and they show no evidence of significant post-accretional parent body alteration. Consequently, they can provide information about grain accretion in the comet-forming region of the outer solar nebula. We have previously reported our comparative study of the sizes and size distributions of crystalline silicate and sulfide grains in CP IDPs, in which we found these components exhibit a size-density relationship consistent with having been sorted together prior to accretion. Here we extend our data set and include GEMS (glass with embedded metal and sulfide), the most abundant amorphous silicate phase observed in CP IDPs. We find that while the silicate and sulfide sorting trend previously observed is maintained, the GEMS size data do not exhibit any clear relationship to these crystalline components. Therefore, GEMS do not appear to have been sorted with the silicate and sulfide crystals. The disparate sorting trends observed in GEMS and the crystalline grains in CP IDPs present an interesting challenge for modeling early transport and accretion processes. They may indicate that several sorting mechanisms operated on these CP IDP components, or alternatively, they may simply be a reflection of different source environments.

  10. 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)

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

    2009-12-01

    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.

  11. 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)

    Mansour, A.; Chigier, N.

    1993-12-01

    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.

  12. Grain size dependent phase stabilities and presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of (1?x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} piezoceramics

    SciTech Connect (OSTI)

    Upadhyay, Ashutosh; Singh, Akhilesh Kumar E-mail: aksingh.mst@itbhu.ac.in

    2015-04-14

    Results of the room temperature structural studies on (1?x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} ceramics using Rietveld analysis of the powder x-ray diffraction data in the composition range 0.28???x???0.45 are presented. The morphotropic phase boundary region exhibits coexistence of monoclinic (space group Pm) and tetragonal (space group P4?mm) phases in the composition range 0.33???x???0.40. The structure is nearly single phase monoclinic (space group Pm) in the composition range 0.28???x???0.32. The structure for the compositions with x???0.45 is found to be predominantly tetragonal with space group P4?mm. Rietveld refinement of the structure rules out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier authors. The Rietveld structure analysis for the sample x?=?.35 calcined at various temperatures reveals that phase fraction of the coexisting phases in the morphotropic phase boundary region varies with grain size. The structural parameters of the two coexisting phases also change slightly with changing grain size.

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

    SciTech Connect (OSTI)

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

    2012-06-28

    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.

  14. Physics of Grain Alignment

    E-Print Network [OSTI]

    Lazarian A

    2000-03-22

    Aligned grains provide one of the easiest ways to study magnetic fields in diffuse gas and molecular clouds. How reliable our conclusions about the inferred magnetic field depends critically on our understanding of the physics of grain alignment. Although grain alignment is a problem of half a century standing recent progress achieved in the field makes us believe that we are approaching the solution of this mystery. I review basic physical processes involved in grain alignment and show why mechanisms that were favored for decades do not look so promising right now. I also discuss why the radiative torque mechanism ignored for more than 20 years looks right now the most powerful means of grain alignment.

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

    SciTech Connect (OSTI)

    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)

    2012-02-01

    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.

  16. Size-dependent solute segregation and total solubility in ultrafine polycrystals: Ca in TiO[sub 2

    SciTech Connect (OSTI)

    Terwilliger, C.D.; Chiang, Y.M. (Massachusetts Inst. of Technology, Cambridge, MA (United States). Dept. of Materials Science and Engineering)

    1995-01-01

    Grain boundary segregation at ultrafine grain sizes has been studied. Using a STEM microanalysis technique to quantify the grain boundary coverage of calcium (0.34 mol%) in TiO[sub 2] ranging in grain size from 50 to 750 nm, it is found that below grain sizes of 150--350 nm, segregation deviates from conventional isotherms, exhibiting a clear size dependence. In this size regime the interfacial area to volume ratio is as important as temperature and composition in determining grain boundary coverage. In the present system, grain boundaries become saturated with calcium when the coverage reaches approximately one half of an equivalent monolayer. The experimental results can be modeled by a statistical thermodynamical treatment of segregation which takes into account the large density of grain boundary sites in this size range. The authors also find direct evidence of enhanced total solubility at very fine grain sizes due to grain boundary segregation.

  17. Grain Accumulation of Selenium Species in Rice (Oryza sativa L.)

    SciTech Connect (OSTI)

    Carey, Anne-Marie; Scheckel, Kirk G.; Lombi, Enzo; Newville, Matt; Choi, Yongseong; Norton, Gareth J.; Price, Adam H.; Meharg, Andrew A.

    2012-09-05

    Efficient Se biofortification programs require a thorough understanding of the accumulation and distribution of Se species within the rice grain. Therefore, the translocation of Se species to the filling grain and their spatial unloading were investigated. Se species were supplied via cut flag leaves of intact plants and excised panicle stems subjected to a {+-} stem-girdling treatment during grain fill. Total Se concentrations in the flag leaves and grain were quantified by inductively coupled plasma mass spectrometry. Spatial accumulation was investigated using synchrotron X-ray fluorescence microtomography. Selenomethionine (SeMet) and selenomethylcysteine (SeMeSeCys) were transported to the grain more efficiently than selenite and selenate. SeMet and SeMeSeCys were translocated exclusively via the phloem, while inorganic Se was transported via both the phloem and xylem. For SeMet- and SeMeSeCys-fed grain, Se dispersed throughout the external grain layers and into the endosperm and, for SeMeSeCys, into the embryo. Selenite was retained at the point of grain entry. These results demonstrate that the organic Se species SeMet and SeMeSeCys are rapidly loaded into the phloem and transported to the grain far more efficiently than inorganic species. Organic Se species are distributed more readily, and extensively, throughout the grain than selenite.

  18. Fine Grained Robotics

    E-Print Network [OSTI]

    Flynn, Anita M.

    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 ...

  19. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Comments?govInstrumentsnoaacrnBarrow, Alaska Outreach Home Roomparticlecontentnumber concentration ARM Datasize

  20. Microwave sintering of nanophase ceramics without concomitant grain growth

    DOE Patents [OSTI]

    Eastman, Jeffrey A. (Woodbridge, IL); Sickafus, Kurt E. (Santa Cruz, NM); Katz, Joel D. (Los Alamos, NM)

    1993-01-01

    A method of sintering nanocrystalline material is disclosed wherein the nanocrystalline material is microwaved to heat the material to a temperature less than about 70% of the melting point of the nanocrystalline material expressed in degrees K. This method produces sintered nanocrystalline material having a density greater than about 95% of theoretical and an average grain size not more than about 3 times the average grain size of the nanocrystalline material before sintering. Rutile TiO.sub.2 as well as various other ceramics have been prepared. Grain growth of as little as 1.67 times has resulted with densities of about 90% of theoretical.

  1. Observation and modeling of polycrystalline grain formation in Ge{sub 2}Sb{sub 2}Te{sub 5}

    SciTech Connect (OSTI)

    Burr, Geoffrey W.; Tchoulfian, Pierre; Topuria, Teya; Nyffeler, Clemens; Virwani, Kumar; Padilla, Alvaro; Shelby, Robert M.; Eskandari, Mona; Jackson, Bryan; Lee, Bong-Sub

    2012-05-15

    The relationship between the polycrystalline nature of phase change materials (such as Ge{sub 2}Sb{sub 2}Te{sub 5}) and the intermediate resistance states of phase change memory (PCM) devices has not been widely studied. A full understanding of such states will require knowledge of how polycrystalline grains form, how they interact with each other at various temperatures, and how the differing electrical (and thermal) characteristics within the grains and at their boundaries combine through percolation to produce the externally observed electrical (and thermal) characteristics of a PCM device. We address the first of these tasks (and introduce a vehicle for the second) by studying the formation of fcc polycrystalline grains from the as-deposited amorphous state in undoped Ge{sub 2}Sb{sub 2}Te{sub 5}. We perform ex situ transmission electron microscopy membrane experiments and then match these observations against numerical simulation. Ramped-anneal experiments show that the temperature ramp-rate strongly influences the median grain size. By truncating such ramped-anneal experiments at various peak temperatures, we convincingly demonstrate that the temperature range over which these grains are established is quite narrow. Subsequent annealing at elevated temperature appears to change these established distributions of grain sizes only slightly. Our numerical simulator--which models nuclei formation through classical nucleation theory and then tracks the subsequent time- and temperature-dependent growth of these grains--can match these experimental observations of initial grain distributions and crystallization temperature both qualitatively and quantitatively. These simulations show that the particular narrow temperature range over which crystallization occurs shifts as a function of temperature ramp-rate, which allows us to quantify the lower portions of the time-temperature-transformation map for Ge{sub 2}Sb{sub 2}Te{sub 5}. Future experiments and extensions of the simulator to investigate temperature-dependent interactions between neighboring grains, and to study nucleation from within the melt-quenched amorphous state, are discussed.

  2. Tables of phase functions, opacities, albedos, equilibrium temperatures, and radiative accelerations of dust grains in exoplanets

    E-Print Network [OSTI]

    Budaj, Jan; Salmeron, Raquel; Hubeny, Ivan

    2015-01-01

    There has been growing observational evidence for the presence of condensates in the atmospheres and/or comet-like tails of extrasolar planets. As a result, systematic and homogeneous tables of dust properties are useful in order to facilitate further observational and theoretical studies. In this paper we present calculations and analysis of non-isotropic phase functions, asymmetry parameter (mean cosine of the scattering angle), absorption and scattering opacities, single scattering albedos, equilibrium temperatures, and radiative accelerations of dust grains relevant for extrasolar planets. Our assumptions include spherical grain shape, Deirmendjian particle size distribution, and Mie theory. We consider several species: corundum/alumina, iron, olivines with 0% and 50% iron content, pyroxenes with 0%, 20% and 60% iron content, carbon at two different temperatures, water ice, liquid water, and ammonia. The presented tables cover the wavelength range of 0.2 to 500 micron and modal particle radii from 0.01 mi...

  3. Collisional effects on nonlinear ion drag force for small grains

    E-Print Network [OSTI]

    Hutchinson, Ian H.

    The ion drag force arising from plasma flow past an embedded spherical grain is calculated self-consistently and non-linearly using particle in cell codes, accounting for ion-neutral collisions. Using ion velocity distribution ...

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

    SciTech Connect (OSTI)

    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

    2012-06-28

    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.

  5. Grains, Water Introduction

    E-Print Network [OSTI]

    Wirosoetisno, Djoko

    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

  6. Understanding for Grain Marketing

    E-Print Network [OSTI]

    O'Laughlin, Jay

    Understanding for Grain Marketing Commodity Futures and Options CIS1089 The Authors: L.D. MakusContracts A futures contract is a standard- ized contract that is traded on a futures market exchange. The contract. This bulletin presents some marketing tools to help producers recognize the sources of price risk

  7. Pest Management For Grain Storage and Fumigation

    E-Print Network [OSTI]

    Dyer, Bill

    Pest Management For Grain Storage and Fumigation Seed Treatment -Pest Control- Grain Storage & Seed MANAGEMENT FOR GRAIN STORAGE AND FUMIGATION Introduction .................................................................................................................................................................. 12 Resistance Management Issues

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

    Office of Energy Efficiency and Renewable Energy (EERE)

    A distinct relationship was found between engine-out and SCR-out PM distributions for single-mode testing.

  9. Effect of gravity on three-dimensional coordination number distribution in liquid phase sintered microstructures

    SciTech Connect (OSTI)

    Tewari, A.; Gokhale, A.M.; Gereman, R.M.

    1999-10-08

    Gravity affects microstructural evolution when a liquid phase is present during sintering. The effect of gravity on the three-dimensional coordination number distribution of tungsten grains in liquid phase sintered heavy alloy specimens is quantitatively characterized. A combination of montage serial sectioning, digital image processing, and unbiased stereological sampling procedures is used to estimate the coordination number distribution in three-dimensional microstructures. The microgravity environment decreases the mean coordination number. However, hardly any isolated grains are observed in the specimens, liquid phase sintered in a microgravity environment. The effect of microgravity on the coordination numbers mainly resides in its effect on the mean coordination number. In all specimens, there is a strong correlation between grain size and coordination number, which can be expressed as [D{sub c}/{bar D}]{sup 2} = C/C{sub 0} where C{sub 0} is the mean coordination number, {bar D} the global average size of the tungsten grains, and D{sub c} the average size of only those grains which have coordination number C.

  10. 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)

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

    2013-04-22

    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.

  11. Microstructure of warm rolling and pearlitic transformation of ultrafine-grained GCr15 steel

    SciTech Connect (OSTI)

    Sun, Jun-Jie; Lian, Fu-Liang; Liu, Hong-Ji; Jiang, Tao; Guo, Sheng-Wu; Du, Lin-Xiu; Liu, Yong-Ning

    2014-09-15

    Pearlitic transformation mechanisms have been investigated in ultra-fine grained GCr15 steel. The ultrafine-grained steel, whose grain size was less than 1 ?m, was prepared by thermo-mechanical treatment at 873 K and then annealing at 923 K for 2 h. Pearlitic transformation was conducted by reheating the ultra-fine grained samples at 1073 K and 1123 K for different periods of time and then cooling in air. Scanning electron microscope observation shows that normal lamellar pearlite, instead of granular cementite and ferrite, cannot be formed when the grain size is approximately less than 4(± 0.6) ?m, which yields a critical grain size for normal lamellar pearlitic transformations in this chromium alloyed steel. The result confirms that grain size has a great influence on pearlitic transformation by increasing the diffusion rate of carbon atoms in the ultra-fine grained steel, and the addition of chromium element doesn't change this pearlitic phase transformation rule. Meanwhile, the grain growth rate is reduced by chromium alloying, which is beneficial to form fine grains during austenitizing, thus it facilitating pearlitic transformation by divorced eutectoid transformation. Moreover, chromium element can form a relatively high gradient in the frontier of the undissolved carbide, which promotes carbide formation in the frontier of the undissolved carbide, i.e., chromium promotes divorced eutectoid transformation. - Highlights: • Ultrafine-grained GCr15 steel was obtained by warm rolling and annealing technology. • Reduction of grain size makes pearlite morphology from lamellar to granular. • Adding Cr does not change normal pearlitic phase transformation rule in UFG steel. • Cr carbide resists grain growth and facilitates pearlitic transformation by DET.

  12. Process for producing large grain cadmium telluride

    DOE Patents [OSTI]

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

    1996-01-16

    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.

  13. Grain Destruction in Interstellar Shocks

    E-Print Network [OSTI]

    B. T. Draine

    1995-08-16

    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.

  14. Supplying materials needed for grain growth characterizations of nano-grained UO2

    SciTech Connect (OSTI)

    Mo, Kun; Miao, Yinbin; Yun, Di; Jamison, Laura M.; Lian, Jie; Yao, Tiankei

    2015-09-30

    This activity is supported by the US Nuclear Energy Advanced Modeling and Simulation (NEAMS) Fuels Product Line (FPL) and aims at providing experimental data for the validation of the mesoscale simulation code MARMOT. MARMOT is a mesoscale multiphysics code that predicts the coevolution of microstructure and properties within reactor fuel during its lifetime in the reactor. It is an important component of the Moose-Bison-Marmot (MBM) code suite that has been developed by Idaho National Laboratory (INL) to enable next generation fuel performance modeling capability as part of the NEAMS Program FPL. In order to ensure the accuracy of the microstructure based materials models being developed within the MARMOT code, extensive validation efforts must be carried out. In this report, we summarize our preliminary synchrotron radiation experiments at APS to determine the grain size of nanograin UO2. The methodology and experimental setup developed in this experiment can directly apply to the proposed in-situ grain growth measurements. The investigation of the grain growth kinetics was conducted based on isothermal annealing and grain growth characterization as functions of duration and temperature. The kinetic parameters such as activation energy for grain growth for UO2 with different stoichiometry are obtained and compared with molecular dynamics (MD) simulations.

  15. Ethanol's Effect on Grain Supply and Prices

    SciTech Connect (OSTI)

    2008-01-01

    This document provides graphical information about ethanol's effect on grain supply and prices, uses of corn, and grain price trends.

  16. Determination of thermodynamic and kinetic properties of grain boundaries using high temperature calorimetry

    SciTech Connect (OSTI)

    Terwilliger, C.D.; Chiang, Y.M. (Massachusetts Inst. of Tech., Cambridge, MA (USA)); Eastman, J.A.; Liao, Y. (Argonne National Lab., IL (USA))

    1991-06-01

    This work explores the use of high temperature differential scanning calorimetry as a novel way in which to measure thermodynamic and kinetic properties of grain boundaries in ceramics. A calorimetric study of grain growth has become practical only recently, with the development of processing methods for nanocrystalline materials (10--50 nm grain size) that have enough grain boundary area and thus grain boundary excess properties to be detected by commercial calorimeters. Here we report results from experiments on nanocrystalline silicon and titanium dioxide. 14 refs., 6 figs.

  17. Grain constraint and size effects in shape memory alloy microwires

    E-Print Network [OSTI]

    Ueland, Stian Melhus

    2013-01-01

    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 ...

  18. Benchmarking the Calculation of Stochastic Heating and Emissivity of Dust Grains in the Context of Radiative Transfer Simulations

    E-Print Network [OSTI]

    Camps, Peter; Bianchi, Simone; Lunttila, Tuomas; Pinte, Christophe; Natale, Giovanni; Juvela, Mika; Fischera, Joerg; Fitzgerald, Michael P; Gordon, Karl; Baes, Maarten; Steinacker, Juergen

    2015-01-01

    We define an appropriate problem for benchmarking dust emissivity calculations in the context of radiative transfer (RT) simulations, specifically including the emission from stochastically heated dust grains. Our aim is to provide a self-contained guide for implementors of such functionality, and to offer insights in the effects of the various approximations and heuristics implemented by the participating codes to accelerate the calculations. The benchmark problem definition includes the optical and calorimetric material properties, and the grain size distributions, for a typical astronomical dust mixture with silicate, graphite and PAH components; a series of analytically defined radiation fields to which the dust population is to be exposed; and instructions for the desired output. We process this problem using six RT codes participating in this benchmark effort, and compare the results to a reference solution computed with the publicly available dust emission code DustEM. The participating codes implement...

  19. Properties and alignment of interstellar dust grains toward Type Ia Supernovae with anomalous polarization curves

    E-Print Network [OSTI]

    Hoang, Thiem

    2015-01-01

    Recent photometric and polarimetric observations of type Ia supernovae (SNe Ia) show unusually low total-to-selective extinction ratio ($R_{V}<2$) and wavelength of maximum polarization ($\\lambda_{max}<0.4\\mu m$) for several SNe Ia, which indicates peculiar properties of interstellar (IS) dust in the SN hosted galaxies and/or the presence of circumstellar (CS) dust. In this paper, we use inversion technique to infer best-fit grain size distribution and alignment function of interstellar grains along the lines of sight toward four SNe Ia with anomalous extinction and polarization data (SNe 1986G, 2006X, 2008fp, and 2014J). We find that to reproduce low values of $R_{V}$, a significant enhancement in the mass of small grains of radius $a< 0.1\\mu m$ is required. For SN 2014J, a simultaneous fit to observed extinction and polarization data is unsuccessful if the entire data is attributed to IS dust (model 1), but a good fit is obtained when accounting for the contribution of CS dust (model 2). For SN 200...

  20. A new scheme of radiation transfer in H II regions including transient heating of grains

    E-Print Network [OSTI]

    S. K. Ghosh; R. P. Verma

    2000-09-21

    A new scheme of radiation transfer for understanding infrared spectra of H II regions, has been developed. This scheme considers non-equilibrium processes (e. g. transient heating of the very small grains, VSG; and the polycyclic aromatic hydrocarbon, PAH) also, in addition to the equilibrium thermal emission from normal dust grains (BG). The spherically symmetric interstellar dust cloud is segmented into a large number of "onion skin" shells in order to implement the non-equilibrium processes. The scheme attempts to fit the observed SED originating from the dust component, by exploring the following parameters : (i) geometrical details of the dust cloud, (ii) PAH size and abundance, (iii) composition of normal grains (BG), (iv) radial distribution of all dust (BG, VSG & PAH). The scheme has been applied to a set of five compact H II regions (IRAS 18116- 1646, 18162-2048, 19442+2427, 22308+5812 & 18434-0242) whose spectra are available with adequate spectral resolution. The best fit models and inferences about the parameters for these sources are presented.

  1. 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)

    Ji, Haojie; Dhomkar, Siddharth; Roy, Bidisha; Kuskovsky, Igor L.; Shuvayev, Vladimir; Deligiannakis, Vasilios; Tamargo, Maria C.; Ludwig, Jonathan; Smirnov, Dmitry; Wang, Alice

    2014-10-28

    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.

  2. The impact of size distribution assumptions in a bulk one-moment microphysics scheme on simulated surface precipitation and storm dynamics during a low-topped supercell case in Belgium

    SciTech Connect (OSTI)

    Van Weverberg, K.; Van Lipzig, N. P. M.; Delobbe, L.

    2011-04-01

    In this research the impact of modifying the size distribution assumptions of the precipitating hydrometeors in a bulk one-moment microphysics scheme on simulated surface precipitation and storm dynamics has been explored for long-lived low-topped supercells in Belgium. It was shown that weighting the largest precipitating ice species of the microphysics scheme to small graupel results in an increase of surface precipitation because of counteracting effects. On the one hand, the precipitation formation process slowed down, resulting in lower precipitation efficiency. On the other hand, latent heat release associated with freezing favored more intense storms. In contrast to previous studies finding decreased surface precipitation when graupel was present in the microphysics parameterization, storms were rather shallow in the authors simulations. This left little time for graupel sublimation. The impact of size distribution assumptions of snow was found to be small, but more realistic size distribution assumptions of rain led to the strongest effect on surface precipitation. Cold pools shrunk because of weaker rain evaporation at the cold pool boundaries, leading to a decreased surface rain area.

  3. The initial microstructure of oxide fuel pellets can play a key role in their performance. At low burnups, the transport of fission products has a strong dependence on oxygen content, grain size distribution, porosity

    E-Print Network [OSTI]

    The initial microstructure of oxide fuel pellets can play a key role in their performance. At low of which, in turn, depend on processing conditions. These microstructural features also affect fuel that detailed studies of the initial microstructure of the fuel, could give insights on the in

  4. Correlating size and composition-dependent effects with magnetic, Mössbauer, and pair distribution function measurements in a family of catalytically active ferrite nanoparticles

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

    Wong, Stanislaus; Papaefthymiou, Georgia C.; Lewis, Crystal S.; Han, Jinkyu; Zhang, Cheng; Li, Qiang; Shi, Chenyang; Abeykoon, A. M.Milinda; Billinge, Simon J.L.; Stach, Eric; et al

    2015-05-06

    The magnetic spinel ferrites, MFe?O? (wherein 'M' = a divalent metal ion such as but not limited to Mn, Co, Zn, and Ni), represent a unique class of magnetic materials in which the rational introduction of different 'M's can yield correspondingly unique and interesting magnetic behaviors. Herein we present a generalized hydrothermal method for the synthesis of single-crystalline ferrite nanoparticles with 'M' = Mg, Fe, Co, Ni, Cu, and Zn, respectively, which can be systematically and efficaciously produced simply by changing the metal precursor. Our protocol can moreover lead to reproducible size control by judicious selection of various surfactants. Asmore »such, we have probed the effects of both (i) size and (ii) chemical composition upon the magnetic properties of these nanomaterials using complementary magnetometry and Mössbauer spectroscopy techniques. The structure of the samples was confirmed by atomic PDF analysis of X-ray and electron powder diffraction data as a function of particle size. These materials retain the bulk spinel structure to the smallest size (i.e., 3 nm). In addition, we have explored the catalytic potential of our ferrites as both (a) magnetically recoverable photocatalysts and (b) biological catalysts, and noted that many of our as-prepared ferrite systems evinced intrinsically higher activities as compared with their iron oxide analogues.« less

  5. MIXTURES OF FINE-GRAINED MINERALS KAOLINITE AND CARBONATE GRAINS

    E-Print Network [OSTI]

    Palomino, Angelica M.

    MIXTURES OF FINE-GRAINED MINERALS À KAOLINITE AND CARBONATE GRAINS ANGELICA M. PALOMINO 1, *, SUSAN, Georgia 30332-0355, USA Abstract--The behavior of mineral mixtures can be significantly different from properties of the individual minerals, and their ensuing effects on interparticle interactions and fabric

  6. Dehumidification Grain Dryer

    SciTech Connect (OSTI)

    Lula, J.W.; Bohnert, G.W.

    1998-05-13

    A new technique developed during this project dries grain with mildly heated, dehumidified air in a closed-loop process. This proposed technique uses about one-tenth the energy and dries grain at a lower temperature, producing less damage to the kernels.Approximately 250 million automotive and truck tires are discarded each year in the U.S. The very properties that ensure a safe ride and long service life make the disposal of these scrap tires difficult. In spite of this, scrap tire recycling/reuse has rapidly grown from 10% in 1985 to over 90% today. The majority of scrap tires that are recycled/reused are burned for fuel in power plants and cement kilns. Since tires have somewhat higher heating value than coal, this would at first seem to be an acceptable option. But burning scrap tires recovers only 25% of the energy originally used to manufacture the rubber. An alternative is to use the scrap tires in the form of crumb rubber, by which 98% of the original energy is recovered. This project sought to explore potential formulations of crumb rubber with various thermoplastic binders, with one goal being developing a material for a low-cost, high-performance roofing composition. What was the state-of-the-art of the product/process prior to initiation of the project? Why was the project needed (e.g., performance, quality, cost, time to market)? Describe the strengths and interests of each party and how they are complementary with respect to the project. What KCP expertise was needed and how did it complement the partner's capabilities?

  7. The Effect Of Electronic Energy Loss On Irradiation-induced Grain Growth In Nanocrystalline Oxides

    SciTech Connect (OSTI)

    Zhang, Yanwen; Aidhy, Dilpuneet S.; Varga, Tamas; Moll, Sandra; Edmondson, Philip D.; Namavar, Fereydoon; Jin, Ke; Ostrouchov, Christopher N.; Weber, William J.

    2014-03-03

    Grain growth of nanocrystalline materials is generally thermally activated, but can also be driven by irradiation at much lower temperature. In nanocrystalline ceria and zirconia, energetic ions deposit their energy to both atomic nuclei and electrons. Our experimental results have shown that irradiationinduced grain growth is dependent on the total energy deposited, where electronic energy loss and elastic collisions between atomic nuclei both contribute to the production of disorder and grain growth. Our atomistic simulations reveal that a high density of disorder near grain boundaries leads to locally rapid grain movement. The additive effect from both electronic excitation and atomic collision cascades on grain growth demonstrated in this work opens up new possibilities for controlling grain sizes to improve functionality of nanocrystalline materials.

  8. Enhanced Solar Energy Absorption by Internally-mixed Black Carbon in Snow Grains

    SciTech Connect (OSTI)

    Flanner, M. G.; Liu, Xiaohong; Zhou, Cheng; Penner, Joyce E.; Jiao, C.

    2012-05-30

    Here we explore light absorption by snowpack containing black carbon (BC) particles residing within ice grains. Basic considerations of particle volumes and BC/snow mass concentrations show that there are generally 0:05-109 BC particles for each ice grain. This suggests that internal BC is likely distributed as multiple inclusions within ice grains, and thus the dynamic effective medium approximation (DEMA) (Chylek and Srivastava, 1983) is a more appropriate optical representation for BC/ice composites than coated-sphere or standard mixing approximations. DEMA calculations show that the 460 nm absorption cross-section of BC/ice composites, normalized to the mass of BC, is typically enhanced by factors of 1.8-2.1 relative to interstitial BC. BC effective radius is the dominant cause of variation in this enhancement, compared with ice grain size and BC volume fraction. We apply two atmospheric aerosol models that simulate interstitial and within-hydrometeor BC lifecycles. Although only {approx}2% of the atmospheric BC burden is cloud-borne, 71-83% of the BC deposited to global snow and sea-ice surfaces occurs within hydrometeors. Key processes responsible for within-snow BC deposition are development of hydrophilic coatings on BC, activation of liquid droplets, and subsequent snow formation through riming or ice nucleation by other species and aggregation/accretion of ice particles. Applying deposition fields from these aerosol models in offline snow and sea-ice simulations, we calculate that 32-73% of BC in global surface snow resides within ice grains. This fraction is smaller than the within-hydrometeor deposition fraction because meltwater flux preferentially removes internal BC, while sublimation and freezing within snowpack expose internal BC. Incorporating the DEMA into a global climate model, we simulate increases in BC/snow radiative forcing of 43-86%, relative to scenarios that apply external optical properties to all BC. We show that snow metamorphism driven by diffusive vapor transfer likely proceeds too slowly to alter the mass of internal BC while it is radiatively active, but neglected processes like wind pumping and convection may play much larger roles. These results suggest that a large portion of BC in surface snowpack may reside within ice grains and increase BC/snow radiative forcing, although measurements to evaluate this are lacking. Finally, previous studies of BC/snow forcing that neglected this absorption enhancement are not necessarily biased low, because of application of absorption-enhancing sulfate coatings to hydrophilic BC, neglect of coincident absorption by dust in snow, and implicit treatment of cloud-borne BC resulting in longer-range transport.

  9. PERCOLATION ON GRAIN BOUNDARY NETWORKS: APPLICATION TO FISSION GAS RELEASE IN NUCLEAR FUELS

    SciTech Connect (OSTI)

    Paul C. Millett

    2012-02-01

    The percolation behavior of grain boundary networks is characterized in two- and three-dimensional lattices with circular macroscale cross-sections that correspond to nuclear fuel elements. The percolation of gas bubbles on grain boundaries, and the subsequent percolation of grain boundary networks is the primary mechanism of fission gas release from nuclear fuels. Both radial cracks and radial gradients in grain boundary property distributions are correlated with the fraction of grain boundaries vented to the free surfaces. Our results show that cracks surprisingly do not significantly increase the percolation of uniform grain boundary networks. However, for networks with radial gradients in boundary properties, the cracks can considerably raise the vented grain boundary content.

  10. A finite element model of grain boundary sliding for nanostructured metals

    E-Print Network [OSTI]

    Jérusalem, Antoine, 1979-

    2004-01-01

    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 ...

  11. Farm Grain Drying and Storage 

    E-Print Network [OSTI]

    Anonymous

    CORN growing is, and is likely to remain, one of British agriculture's major enterprises. A very high proportion of the resulting harvest is now handled by combine harvesters, which bring with them problems of grain handling, ...

  12. Food grain policy in Bangladesh

    E-Print Network [OSTI]

    Rausser, Gordon C.

    1981-01-01

    ~o. FOOD GAAIN POLICY IN BANGLADESH by Gordon C. Rausser ;.period of time before Bangladesh becomes self-sufficient. Infor Food Grains in Bangladesh, Unpublished Ph.D. thesis,

  13. Thermal Flipping of Interstellar Grains

    E-Print Network [OSTI]

    Joseph C. Weingartner

    2008-08-27

    In interstellar dust grains, internal processes dissipate rotational kinetic energy. The dissipation is accompanied by thermal fluctuations, which transfer energy from the vibrational modes to rotation. Together, these processes are known as internal relaxation. For the past several years, internal relaxation has been thought to give rise to thermal flipping, with profound consequences for grain alignment theory. I show that thermal flipping is not possible in the limit that the inertia tensor does not vary with time.

  14. Dense, finely, grained composite materials

    DOE Patents [OSTI]

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

    1990-01-01

    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.

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

    E-Print Network [OSTI]

    Xiao, Jingfeng

    RESEARCH ARTICLE The contribution of China's Grain to Green Program to carbon sequestration Dan Liu to forests. However, the magnitude and distribution of carbon sequestration induced by GGP remain unknown with large sequestration in southern China. The economic benefits of carbon sequestration from the GGP were

  16. Moment equations for chemical reactions on interstellar dust grains

    E-Print Network [OSTI]

    Azi Lipshtat; Ofer Biham

    2002-12-09

    While most chemical reactions in the interstellar medium take place in the gas phase, those occurring on the surfaces of dust grains play an essential role. Chemical models based on rate equations including both gas phase and grain surface reactions have been used in order to simulate the formation of chemical complexity in interstellar clouds. For reactions in the gas phase and on large grains, rate equations, which are highly efficient to simulate, are an ideal tool. However, for small grains under low flux, the typical number of atoms or molecules of certain reactive species on a grain may go down to order one or less. In this case the discrete nature of the opulations of reactive species as well as the fluctuations become dominant, thus the mean-field approximation on which the rate equations are based does not apply. Recently, a master equation approach, that provides a good description of chemical reactions on interstellar dust grains, was proposed. Here we present a related approach based on moment equations that can be obtained from the master equation. These equations describe the time evolution of the moments of the distribution of the population of the various chemical species on the grain. An advantage of this approach is the fact that the production rates of molecular species are expressed directly in terms of these moments. Here we use the moment equations to calculate the rate of molecular hydrogen formation on small grains. It is shown that the moment equation approach is efficient in this case in which only a single reactive specie is involved. The set of equations for the case of two species is presented and the difficulties in implementing this approach for complex reaction networks involving multiple species are discussed.

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

    SciTech Connect (OSTI)

    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

    2014-08-01

    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.

  18. Relative entropy and optimization-driven coarse-graining methods in VOTCA

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

    Mashayak, S. Y.; Jochum, Mara N.; Koschke, Konstantin; Aluru, N. R.; Rühle, Victor; Junghans, Christoph; Huang, Xuhui

    2015-07-20

    We discuss recent advances of the VOTCA package for systematic coarse-graining. Two methods have been implemented, namely the downhill simplex optimization and the relative entropy minimization. We illustrate the new methods by coarse-graining SPC/E bulk water and more complex water-methanol mixture systems. The CG potentials obtained from both methods are then evaluated by comparing the pair distributions from the coarse-grained to the reference atomistic simulations.We have also added a parallel analysis framework to improve the computational efficiency of the coarse-graining process.

  19. 1 INTRODUCTION 1.1 Optical sizing

    E-Print Network [OSTI]

    Maerz, Norbert H.

    mining operation, from the drilling and blasting to the final product; the material size dictates all downstream operating costs. Previously, the only way to measure a size distribution was to stop production

  20. Insects Injurious to Stored Grain

    E-Print Network [OSTI]

    Price, R. H.

    1894-01-01

    . ............................... J. W. PHILLIPS,. Wichita Falls. \\Vichita Co. do. :in. an. .or. ist. an. . . rot parag c i' blc raph, for for graph, P 1 of fig. 4 R"1 ?'A. Tnsch Life, read Insect I 1894, read 1890. upinting. I, for Alnl , read pu ;umois, r... pating. bead Angl Life. TEXAS AGRICULTURAL EXPERIMENT STATION. INSECT'S INJURIOUS TO STORED GRAIN R. H. PRICE, B. S. L L I only a , scarce! ons to nl~t~t~i up th seed the st " a clu resto Th Febr~ . . The injury done to stored grain...

  1. Grain growth and phase stability of nanocrystalline cubic zirconia under ion irradiation

    SciTech Connect (OSTI)

    Zhang, Yanwen; Jiang, Weilin; Wang, Chong M.; Namavar, Fereydoon; Edmondson, Philip D.; Zhu, Zihua; Gao, Fei; Lian, Jie; Weber, William J.

    2010-11-10

    Grain growth, oxygen stoichiometry and phase stability of nanostructurally-stabilized zirconia (NSZ) in pure cubic phase are investigated under 2 MeV Au ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with dose, and follows a power law (n=6) to a saturation value of ~30 nm that decreases with temperature. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that thermal grain growth is not activated and defect-stimulated grain growth is the dominating mechanism. While cubic phase is perfectly retained and no new phases are identified after the high-dose irradiations, reduction of oxygen in the irradiated NSZ films is detected. The ratio of O to Zr decreases from ~2.0 for the as-deposited films to ~1.65 after irradiation to ~35 dpa. Significant increase of oxygen vacancies in nanocrystalline zirconia suggests substantially enhanced oxygen diffusion under ion irradiation, a materials behavior far from equilibrium. The oxygen deficiency may be essential in stabilizing cubic phase to larger grain sizes.

  2. Grain Growth and Phase Stability of Nanocrystalline Cubic Zirconia under Ion Irradiation

    SciTech Connect (OSTI)

    Zhang, Yanwen; Jiang, Weilin; Wang, Chongmin; Namavar, Fereydoon; Edmondson, Philip D.; Zhu, Zihua; Gao, Fei; Lian, Jie; Weber, William J

    2010-01-01

    Grain growth, oxygen stoichiometry and phase stability of nanostructurally-stabilized cubic zirconia (NSZ) are investigated under 2 MeV Au ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with dose, and follows a power law (n=6) to a saturation value of ~30 nm that decreases with temperature. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that the grain growth is not thermally activated and irradiation-induced grain growth is the dominating mechanism. While the cubic structure is retained and no new phases are identified after the high-dose irradiations, oxygen reduction in the irradiated NSZ films is detected. The ratio of O to Zr decreases from ~2.0 for the as-deposited films to ~1.65 after irradiation to ~35 dpa. The loss of oxygen suggests a significant increase of oxygen vacancies in nanocrystalline zirconia under ion irradiation. The oxygen deficiency may be essential in stabilizing the cubic phase to larger grain sizes.

  3. Stored Grain Department of Entomology

    E-Print Network [OSTI]

    Pittendrigh, Barry

    of plastic produced annually by Nigeria alone (Ogunniyi, 1990). Given the growing interest in the technology, Base de Maradi, Niger The Purdue Improved Crop Storage (PICS) bag is a simple and effective technology for reducing grain losses to insects during postharvest storage. The technology was initially developed

  4. Stored Grain Department of Entomology

    E-Print Network [OSTI]

    Pittendrigh, Barry

    toxicity. As a result, most low-resource cowpea farmers often sell their grain at harvest ­ when the price (Seck et al., 1996) ­ because insects respire aerobically, i.e., they use oxygen to generate energy from their food. They need energy to grow, develop and reproduce. Feeding and growing larvae burn up the oxygen

  5. Information-theoretic significance of the Wigner distribution

    E-Print Network [OSTI]

    Frieden, B R; Soffer, Bernard H

    2006-01-01

    cance of the Wigner distribution B. Roy Frieden College ofA coarse-grained Wigner distribution p W ?x , ? ? obeyingon the Wigner distribution. A. Positivity property of coarse

  6. AGB stars and presolar grains

    SciTech Connect (OSTI)

    Busso, M.; Trippella, O. [INFN and University of Perugia, Perugia (Italy); Maiorca, E. [INAF - Arcetri Astrophysical Observatory, Firenze, Italy and INFN - Section of Perugia, Perugia (Italy); Palmerini, S. [Departamento de Fìsica Teòrica y del Cosmsos, Universidad de Granada, Granada (Spain)

    2014-05-09

    Among presolar materials recovered in meteorites, abundant SiC and Al{sub 2}O{sub 3} grains of AGB origins were found. They showed records of C, N, O, {sup 26}Al and s-element isotopic ratios that proved invaluable in constraining the nucleosynthesis models for AGB stars [1, 2]. In particular, when these ratios are measured in SiC grains, they clearly reveal their prevalent origin in cool AGB circumstellar envelopes and provide information on both the local physics and the conditions at the nucleosynthesis site (the H- and He-burning layers deep inside the structure). Among the properties ascertained for the main part of the SiC data (the so-called mainstream ones), we mention a large range of {sup 14}N/{sup 15}N ratios, extending below the solar value [3], and {sup 12}C/{sup 13}C ratios ? 30. Other classes of grains, instead, display low carbon isotopic ratios (? 10) and a huge dispersion for N isotopes, with cases of large {sup 15}N excess. In the same grains, isotopes currently feeded by slow neutron captures reveal the characteristic pattern expected from this process at an efficiency slightly lower than necessary to explain the solar main s-process component. Complementary constraints can be found in oxide grains, especially Al{sub 2}O{sub 3} crystals. Here, the oxygen isotopes and the content in {sup 26}Al are of a special importance for clarifying the partial mixing processes that are known to affect evolved low-mass stars. Successes in modeling the data, as well as problems in explaining some of the mentioned isotopic ratios through current nucleosynthesis models are briefly outlined.

  7. Optical method for the determination of grain orientation in films

    DOE Patents [OSTI]

    Maris, Humphrey J. (Barrington, RI)

    2001-01-01

    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.

  8. Optical method for the determination of grain orientation in films

    DOE Patents [OSTI]

    Maris, Humphrey J.

    2003-05-13

    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.

  9. LI,HOSPEDALES,SONG,GONG: FINE-GRAINED SKETCH-BASED IMAGE RETRIEVAL 1 Fine-Grained Sketch-Based Image Retrieval

    E-Print Network [OSTI]

    Gong, Shaogang

    LI,HOSPEDALES,SONG,GONG: FINE-GRAINED SKETCH-BASED IMAGE RETRIEVAL 1 Fine-Grained Sketch.hospedales@qmul.ac.uk Yi-Zhe Song yizhe.song@qmul.ac.uk Shaogang Gong s.gong@qmul.ac.uk Queen Mary University of London. It may be distributed unchanged freely in print or electronic forms. #12;2 LI,HOSPEDALES,SONG,GONG: FINE

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

    SciTech Connect (OSTI)

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

    1996-12-31

    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.

  11. Suppression of Twinning and Phase Transformation in an Ultrafine Grained 2 GPa Strong Metastable Austenitic Steel: Experiment and Simulation

    SciTech Connect (OSTI)

    Shen, Yongfeng; Jia, Nan; Wang, Y. D.; Sun, Xin; Zuo, Liang; Raabe, Dierk

    2015-07-17

    An ultrafine-grained 304 austenitic 18 wt.%Cr-8 wt.%Ni stainless steel with a grain size of ~270 nm was synthesized by accumulative rolling (67 % total reduction) and annealing (550 °C, 150s). Uniaxial tensile testing at room temperature reveals an extremely high yield strength of 1890 ± 50MPa and a tensile strength of 2050 ± 30MPa, while the elongation reaches 6 ± 1%. Experimental characterization on samples with different grain sizes between 270 nm and 35 ?m indicates that both, deformation twinning and martensitic phase transformation are significantly retarded with increasing grain refinement. A crystal plasticity finite element model incorporating a constitutive law reflecting the grain size-controlled dislocation slip and deformation twinning captures the micromechanical behavior of the steels with different grain sizes. Comparison of simulation and experiment shows that the deformation of ultrafine-grained 304 steels is dominated by the slip of partial dislocations, whereas for coarse-grained steels dislocation slip, twinning and martensite formation jointly contribute to the shape change.

  12. Characterizing Uncertainties in Ice Particle Size Distributions

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D BGene Network ShapingDate:Characterization ofArcticUncertainties in

  13. 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)

    Sullivan, Edmund J.; Anderson, Michael T.; Norris, Wallace

    2012-09-17

    Pressurized thermal shock (PTS) events are system transients in a pressurized water reactor (PWR) in which there is a rapid operating temperature cool-down that results in cold vessel temperatures with or without repressurization of the vessel. The rapid cooling of the inside surface of the reactor pressure vessel (RPV) causes thermal stresses that can combine with stresses caused by high pressure. The aggregate effect of these stresses is an increase in the potential for fracture if a pre-existing flaw is present in a material susceptible to brittle failure. The ferritic, low alloy steel of the reactor vessel beltline adjacent to the core, where neutron radiation gradually embrittles the material over the lifetime of the plant, can be susceptible to brittle fracture. The PTS rule, described in the Code of Federal Regulations, Title 10, Section 50.61 (§50.61), “Fracture Toughness Requirements for Protection against Pressurized Thermal Shock Events,” adopted on July 23, 1985, establishes screening criteria to ensure that the potential for a reactor vessel to fail due to a PTS event is deemed to be acceptably low. The U.S. Nuclear Regulatory Commission (NRC) completed a research program that concluded that the risk of through-wall cracking due to a PTS event is much lower than previously estimated. The NRC subsequently developed a rule, §50.61a, published on January 4, 2010, entitled “Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events” (75 FR 13). Use of the new rule by licensees is optional. The §50.61a rule differs from §50.61 in that it requires licensees who choose to follow this alternate method to analyze the results from periodic volumetric examinations required by the ASME Code, Section XI, Rules for Inservice Inspection (ISI) of Nuclear Power Plants. These analyses are intended to determine if the actual flaw density and size distribution in the licensee’s reactor vessel beltline welds are bounded by the flaw density and size distribution values used in the PTS technical basis. Under a contract with the NRC, Pacific Northwest National Laboratory (PNNL) has been working on a program to assess the ability of current inservice inspection (ISI)-ultrasonic testing (UT) techniques, as qualified through ASME Code, Appendix VIII, Supplements 4 and 6, to detect small fabrication or inservice-induced flaws located in RPV welds and adjacent base materials. As part of this effort, the investigators have pursued an evaluation, based on the available information, of the capability of UT to provide flaw density/distribution inputs for making RPV weld assessments in accordance with §50.61a. This paper presents the results of an evaluation of data from the 1993 Browns Ferry Nuclear Plant, Unit 3, Spirit of Appendix VIII reactor vessel examination, a comparison of the flaw density/distribution from this data with the distribution in §50.61a, possible reasons for differences, and plans and recommendations for further work in this area.

  14. STOCK: Structure mapper and online coarse-graining kit for molecular simulations

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

    Bevc, Staš; Junghans, Christoph; Praprotnik, Matej

    2015-03-15

    We present a web toolkit STructure mapper and Online Coarse-graining Kit for setting up coarse-grained molecular simulations. The kit consists of two tools: structure mapping and Boltzmann inversion tools. The aim of the first tool is to define a molecular mapping from high, e.g. all-atom, to low, i.e. coarse-grained, resolution. Using a graphical user interface it generates input files, which are compatible with standard coarse-graining packages, e.g. VOTCA and DL_CGMAP. Our second tool generates effective potentials for coarse-grained simulations preserving the structural properties, e.g. radial distribution functions, of the underlying higher resolution model. The required distribution functions can be providedmore »by any simulation package. Simulations are performed on a local machine and only the distributions are uploaded to the server. The applicability of the toolkit is validated by mapping atomistic pentane and polyalanine molecules to a coarse-grained representation. Effective potentials are derived for systems of TIP3P (transferable intermolecular potential 3 point) water molecules and salt solution. The presented coarse-graining web toolkit is available at http://stock.cmm.ki.si.« less

  15. Irradiation behaviour of the large grained UO{sub 2} fuel pellet in the transient conditions

    SciTech Connect (OSTI)

    Kosaka, Yuji; Watanabe, Seiichi; Arakawa, Yasushi

    2007-07-01

    In order to achieve a high duty fuel rod design, it is the key issue to suppress the fission gas release from the view point of the fuel rod inner pressure design. The large grain UO{sub 2} pellet is one of the candidates to meet such a requirement by reducing the fission gas release especially at high power and/or high burnup. We have demonstrated the fuel performance of the large grain pellet in the PWR irradiation conditions, which was fabricated with no additive but with active UO{sub 2} powder through the conventional pelletizing process for the normal grain size pellet. According to the mechanism of the fission gas retention, there may be a concern about the larger gas bubble swelling of the large grain pellet at the power transient conditions which may increase the potential of the PCMI failure. In this paper, we focus on the differences of the dimensional change in comparison among the pellets with the different grain sizes at the power transient conditions. The power ramp tests were carried out on the high burnup fuel rods of normal and large grain pellet with no additive, which had been irradiated in the PWR conditions up to around 60 GWd/t at peak position. The detailed PIE results revealed that the volume increment due to the power ramp clearly showed the dependence on the grain size as well as the fission gas release and suggested that the larger grain with no additive may suppress the gas bubble swelling at the power transient conditions. According to the experimental results, it is concluded that the large grain pellet with no additive does not deteriorate the irradiation performance during the power transient conditions from the view point of the gas bubble swelling. (authors)

  16. Commercial Storage and Handling of Sorghum Grain

    E-Print Network [OSTI]

    Brown, Charles W.; Moore, Clarence A.

    1963-01-01

    relative humidity and relatively hot summer and cold winter temperatures. M7inter temperatures below freezing are common. Since harvest occurs from September through November, the temperature of new grain moving into storage is not high. Sorghum grain... a cross section of physical and economic conditions under which sorghum grain is produced, handled and stored were selected for study of storage and handling facilities and practices by commercial grain storage operators. The High Plains...

  17. Grain alignment in starless cores

    SciTech Connect (OSTI)

    Jones, T. J.; Bagley, M. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Krejny, M. [Cree Inc., 4600 Silicon Dr., Durham, NC (United States); Andersson, B.-G. [SOFIA Science Center, USRA, Moffett Field, CA (United States); Bastien, P., E-mail: tjj@astro.umn.edu [Centre de recherche en astrophysique du Québec and Départment de Physique, Université de Montréal, Montréal (Canada)

    2015-01-01

    We present near-IR polarimetry data of background stars shining through a selection of starless cores taken in the K band, probing visual extinctions up to A{sub V}?48. We find that P{sub K}/?{sub K} continues to decline with increasing A{sub V} with a power law slope of roughly ?0.5. Examination of published submillimeter (submm) polarimetry of starless cores suggests that by A{sub V}?20 the slope for P versus ? becomes ??1, indicating no grain alignment at greater optical depths. Combining these two data sets, we find good evidence that, in the absence of a central illuminating source, the dust grains in dense molecular cloud cores with no internal radiation source cease to become aligned with the local magnetic field at optical depths greater than A{sub V}?20. A simple model relating the alignment efficiency to the optical depth into the cloud reproduces the observations well.

  18. Effect of martensite to austenite reversion on the formation of nano/submicron grained AISI 301 stainless steel

    SciTech Connect (OSTI)

    Karimi, M.; Najafizadeh, A.; Kermanpur, A.; Eskandari, M.

    2009-11-15

    The martensite to austenite reversion behavior of 90% cold rolled AISI 301 stainless steel was investigated in order to refine the grain size. Cold rolled specimens were annealed at 600-900 deg. C, and subsequently characterized by scanning electron microscopy, X-ray diffraction, Feritscope, and hardness measurements. The effects of annealing parameters on the formation of fully-austenitic nano/submicron grained structure and the mechanisms involved were studied. It was found that annealing at 800 deg. C for 10 s exhibited the smallest average austenite grain size of 240 {+-} 60 nm with an almost fully-austenitic structure.

  19. Aerosol mobility size spectrometer

    DOE Patents [OSTI]

    Wang, Jian (Port Jefferson, NY); Kulkarni, Pramod (Port Jefferson Station, NY)

    2007-11-20

    A device for measuring aerosol size distribution within a sample containing aerosol particles. The device generally includes a spectrometer housing defining an interior chamber and a camera for recording aerosol size streams exiting the chamber. The housing includes an inlet for introducing a flow medium into the chamber in a flow direction, an aerosol injection port adjacent the inlet for introducing a charged aerosol sample into the chamber, a separation section for applying an electric field to the aerosol sample across the flow direction and an outlet opposite the inlet. In the separation section, the aerosol sample becomes entrained in the flow medium and the aerosol particles within the aerosol sample are separated by size into a plurality of aerosol flow streams under the influence of the electric field. The camera is disposed adjacent the housing outlet for optically detecting a relative position of at least one aerosol flow stream exiting the outlet and for optically detecting the number of aerosol particles within the at least one aerosol flow stream.

  20. Grain boundaries in coated conductors

    E-Print Network [OSTI]

    Weigand, Marcus

    2010-07-06

    ,757 • Bibliography: 5,087 ix Publications and Conference Presentations This thesis led to the following publications: • M. Weigand, S. C. Speller, G. M. Hughes, N. A. Rutter, S. Lozano-Perez, C. R. M. Grovenor and J. H. Durrell: “Individual grain boundary properties... and overall performance of metal-organic deposition coated conductors ”, Phys. Rev. B 81, 174537 (2010) • R. Hühne, J. Eickemeyer, V. S. Sarma, A. Güth, T. Thersleff, J. Freudenberger, O. de Haas, M. Weigand, J. H. Durrell, L. Schultz and B. Holzapfel: “Ap...

  1. Size-dependent structure of silver nanoparticles under high pressure

    SciTech Connect (OSTI)

    Koski, Kristie Jo

    2008-12-31

    Silver noble metal nanoparticles that are<10 nm often possess multiply twinned grains allowing them to adopt shapes and atomic structures not observed in bulk materials. The properties exhibited by particles with multiply twinned polycrystalline structures are often far different from those of single-crystalline particles and from the bulk. I will present experimental evidence that silver nanoparticles<10 nm undergo a reversible structural transformation under hydrostatic pressures up to 10 GPa. Results for nanoparticles in the intermediate size range of 5 to 10 nm suggest a reversible linear pressure-dependent rhombohedral distortion which has not been previously observed in bulk silver. I propose a mechanism for this transitiion that considers the bond-length distribution in idealized multiply twinned icosahedral particles. Results for nanoparticles of 3.9 nm suggest a reversible linear pressure-dependent orthorhombic distortion. This distortion is interpreted in the context of idealized decahedral particles. In addition, given these size-dependent measurements of silver nanoparticle compression with pressure, we have constructed a pressure calibration curve. Encapsulating these silver nanoparticles in hollow metal oxide nanospheres then allows us to measure the pressure inside a nanoshell using x-ray diffraction. We demonstrate the measurement of pressure gradients across nanoshells and show that these nanoshells have maximum resolved shear strengths on the order of 500 MPa to IGPa.

  2. LUNAR DUST GRAIN CHARGING BY ELECTRON IMPACT: COMPLEX ROLE OF SECONDARY ELECTRON EMISSIONS IN SPACE ENVIRONMENTS

    SciTech Connect (OSTI)

    Abbas, M. M.; Craven, P. D.; LeClair, A. C.; Spann, J. F.; Tankosic, D.

    2010-08-01

    Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with radiation from nearby sources, or by electron/ion collisions by sticking or secondary electron emissions (SEEs). The high vacuum environment on the lunar surface leads to some unusual physical and dynamical phenomena involving dust grains with high adhesive characteristics, and levitation and transportation over long distances. Knowledge of the dust grain charges and equilibrium potentials is important for understanding a variety of physical and dynamical processes in the interstellar medium, and heliospheric, interplanetary/planetary, and lunar environments. It has been well recognized that the charging properties of individual micron-/submicron-size dust grains are expected to be substantially different from the corresponding values for bulk materials. In this paper, we present experimental results on the charging of individual 0.2-13 {mu}m size dust grains selected from Apollo 11 and 17 dust samples, and spherical silica particles by exposing them to mono-energetic electron beams in the 10-200 eV energy range. The dust charging process by electron impact involving the SEEs discussed is found to be a complex charging phenomenon with strong particle size dependence. The measurements indicate substantial differences between the polarity and magnitude of the dust charging rates of individual small-size dust grains, and the measurements and model properties of corresponding bulk materials. A more comprehensive plan of measurements of the charging properties of individual dust grains for developing a database for realistic models of dust charging in astrophysical and lunar environments is in progress.

  3. Lookup Tables: Fine-Grained Partitioning for Distributed Databases

    E-Print Network [OSTI]

    Curino #2 , Evan P. C. Jones #3 , Sam Madden #4 # Massachusetts Institute of Technology, USA 1 altat

  4. Distribution of Residence Times of Grains in Sandpile Models.

    E-Print Network [OSTI]

    Institute of Fundamental Research, Mumbai For the degree of Doctor of Philosophy in Physics by Punyabrata Research Mumbai July, 2006 #12;Acknowledgments I am highly grateful to my supervisor, Professor Deepak Dhar

  5. Can amphiphile architecture directly control vesicle size?

    E-Print Network [OSTI]

    M. J. Greenall; C. M. Marques

    2013-01-28

    Bilayer membranes self-assembled from simple amphiphiles in solution always have a planar ground-state shape. This is a consequence of several internal relaxation mechanisms of the membrane and prevents the straightforward control of vesicle size. Here, we show that this principle can be circumvented and that direct size control by molecular design is a realistic possibility. Using coarse-grained calculations, we design tetrablock copolymers that form membranes with a preferred curvature, and demonstrate how to form low-polydispersity vesicles while suppressing micellization.

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

    SciTech Connect (OSTI)

    Sirono, Sin-iti

    2013-03-01

    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.

  7. PRODUCTION OF CARBON-RICH PRESOLAR GRAINS FROM MASSIVE STARS

    SciTech Connect (OSTI)

    Pignatari, M.; Thielemann, F.-K. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Wiescher, M.; De Boer, R. J. [University of Notre Dame, Department of Physics, Notre Dame, IN 46556 (United States); Timmes, F. X.; Herwig, F. [Joint Institute for Nuclear Astrophysics, Notre Dame, IN 46556 (United States); Fryer, C. [Computational Physics and Methods (CCS-2), LANL, Los Alamos, NM 87545 (United States); Heger, A. [Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, Vic 3800 (Australia); Hirschi, R. [Keele University, Keele, Staffordshire ST5 5BG (United Kingdom)

    2013-04-20

    About a year after core-collapse supernova, dust starts to condense in the ejecta. In meteorites, a fraction of C-rich presolar grains (e.g., silicon carbide (SiC) grains of Type-X and low density graphites) are identified as relics of these events, according to the anomalous isotopic abundances. Several features of these abundances remain unexplained and challenge the understanding of core-collapse supernovae explosions and nucleosynthesis. We show, for the first time, that most of the measured C-rich grain abundances can be accounted for in the C-rich material from explosive He burning in core-collapse supernovae with high shock velocities and consequent high temperatures. The inefficiency of the {sup 12}C({alpha}, {gamma}){sup 16}O reaction relative to the rest of the {alpha}-capture chain at T > 3.5 Multiplication-Sign 10{sup 8} K causes the deepest He-shell material to be carbon-rich and silicon-rich, and depleted in oxygen. The isotopic ratio predictions in part of this material, defined here as the C/Si zone, are in agreement with the grain data. The high-temperature explosive conditions that our models reach at the bottom of the He shell can also be representative of the nucleosynthesis in hypernovae or in the high-temperature tail of a distribution of conditions in asymmetric supernovae. Finally, our predictions are consistent with the observation of large {sup 44}Ca/{sup 40}Ca observed in the grains. This is due to the production of {sup 44}Ti together with {sup 40}Ca in the C/Si zone and/or to the strong depletion of {sup 40}Ca by neutron captures.

  8. Diseases of Small Grains in Texas. 

    E-Print Network [OSTI]

    Atkins, I. M.; Futrell, M. C.

    1958-01-01

    Diseases - of SMALL GRAINS in cooperation with the UNITED STATES DEPARTMENT OF AGRICULTURE TEXAS AGRICULTURAL EXPERIMENT STATION R. D. LEWIS, DIRECTOR. COLLEGE STATIOKJ. TEXAS DIGEST CONTENTS 1 Diseases of small grains are important factors... and international signif- icance. The fall infection, winter survival and spring increase in South Texas of airborne pathogens, such as the cereal rusts, may endanger the small grain crops throughout Texas and other states. Diseases of wheat, which consistently...

  9. Transport of charged dust grains into the galactic halo

    E-Print Network [OSTI]

    Khoperskov, S A

    2014-01-01

    We develop a 3D dynamical model of dust outflows from galactic discs. The outflows are initiated by multiple SN explosions in a magnetized interstellar medium (ISM) with a gravitationally stratified density distribution. Dust grains are treated as particles in cells interacting collisionally with gas, and forced by stellar radiation of the disc and Lorenz force. We show that magnetic field plays a crucial role in accelerating the charged dust grains and expelling them out of the disc: in 10--20~Myr they can be elevated at distances up to 10~kpc above the galactic plane. The dust-to-gas ratio in the outflowing medium varies in the range $5 \\cdot 10^{-4} - 5 \\cdot 10^{-2}$ along the vertical stream. Overall the dust mass loss rate depends on the parameters of ISM and may reach up to $3\\times 10^{-2}$~\\Msun~yr$^{-1}$

  10. Nucleation and Growth of Crystalline Grains in RF-Sputtered TiO2Films

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

    Johnson, J. C.; Ahrenkiel, S. P.; Dutta, P.; Bommisetty, V. R.

    2009-01-01

    AmorphousTiO2thin films were radio frequency sputtered onto siliconmonoxide and carbon support films on molybdenum transmission electron microscope (TEM) grids and observed during in situ annealing in a TEM heating stage at250?C. The evolution of crystallization is consistent with a classical model of homogeneous nucleation and isotropic grain growth. The two-dimensional grain morphology of the TEM foil allowed straightforward recognition of amorphous and crystallized regions of the films, for measurement of crystalline volume fraction and grain number density. By assuming that the kinetic parameters remain constant beyond the onset of crystallization, the final average grain size was computed, using an analyticalmore »extrapolation to the fully crystallized state. Electron diffraction reveals a predominance of the anatase crystallographic phase.« less

  11. Nucleation and Growth of Crystalline Grains in RF-Sputtered TiO 2 Films

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

    Johnson, J. C.; Ahrenkiel, S. P.; Dutta, P.; Bommisetty, V. R.

    2009-01-01

    Amorphous TiO 2 thin films were radio frequency sputtered onto siliconmonoxide and carbon support films on molybdenum transmission electron microscope (TEM) grids and observed during in situ annealing in a TEM heating stage at 250 ? C. The evolution of crystallization is consistent with a classical model of homogeneous nucleation and isotropic grain growth. The two-dimensional grain morphology of the TEM foil allowed straightforward recognition of amorphous and crystallized regions of the films, for measurement of crystalline volume fraction and grain number density.more »By assuming that the kinetic parameters remain constant beyond the onset of crystallization, the final average grain size was computed, using an analytical extrapolation to the fully crystallized state. Electron diffraction reveals a predominance of the anatase crystallographic phase. « less

  12. Computational and theoretical aspects of a grain-boundary model that accounts for grain misorientation and grain-boundary orientation

    E-Print Network [OSTI]

    D. Gottschalk; A. McBride; B. D. Reddy; A. Javili; P. Wriggers; C. B. Hirschberger

    2015-05-06

    A detailed theoretical and numerical investigation of the infinitesimal single-crystal gradient plasticity and grain-boundary theory of Gurtin (2008) "A theory of grain boundaries that accounts automatically for grain misorientation and grain-boundary orientation". Journal of the Mechanics and Physics of Solids 56 (2), 640-662, is performed. The governing equations and flow laws are recast in variational form. The associated incremental problem is formulated in minimization form and provides the basis for the subsequent finite element formulation. Various choices of the kinematic measure used to characterize the ability of the grain boundary to impede the flow of dislocations are compared. An alternative measure is also suggested. A series of three-dimensional numerical examples serve to elucidate the theory.

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

    E-Print Network [OSTI]

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

  14. Coarse graining and control theory model reduction

    E-Print Network [OSTI]

    Carlson, Jean

    Coarse graining and control theory model reduction David E. Reynolds 1 ABSTRACT: We explain a method, inspired by control the- ory model reduction and interpolation theory, that rigorously applicable to nonequilibrium systems. KEY WORDS: coarse graining; control theory; model reduc- tion; Hankel

  15. Coarse graining and control theory model reduction

    E-Print Network [OSTI]

    Carlson, Jean

    Coarse graining and control theory model reduction David E. Reynolds 1 ABSTRACT: We explain a method, inspired by control the­ ory model reduction and interpolation theory, that rigorously applicable to nonequilibrium systems. KEY WORDS: coarse graining; control theory; model reduc­ tion; Hankel

  16. A size-dependent crystal plasticity finite-element model for creep and load shedding in polycrystalline titanium alloys

    E-Print Network [OSTI]

    Ghosh, Somnath

    A size-dependent crystal plasticity finite-element model for creep and load shedding Abstract A rate-dependent anisotropic elastic-crystal plasticity based finite-element (FE) model with size in the crystal plasticity relations are expressed as Hall­Petch type relations, where the grain size, lath size

  17. Coarse-grained Classification of Web Sites by Their Structural Properties

    E-Print Network [OSTI]

    Lindemann, Christoph

    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

  18. Phloem Transport of Arsenic Species from Flag Leaf to Grain During Grain Filling

    SciTech Connect (OSTI)

    A Carey; G Norton; C Deacon; K Scheckel; E Lombi; T Punshon; M Guerinot; A Lanzirotti; M Newville; et al.

    2011-12-31

    Strategies to reduce arsenic (As) in rice grain, below concentrations that represent a serious human health concern, require that the mechanisms of As accumulation within grain be established. Therefore, retranslocation of As species from flag leaves into filling rice grain was investigated. Arsenic species were delivered through cut flag leaves during grain fill. Spatial unloading within grains was investigated using synchrotron X-ray fluorescence (SXRF) microtomography. Additionally, the effect of germanic acid (a silicic acid analog) on grain As accumulation in arsenite-treated panicles was examined. Dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) were extremely efficiently retranslocated from flag leaves to rice grain; arsenate was poorly retranslocated, and was rapidly reduced to arsenite within flag leaves; arsenite displayed no retranslocation. Within grains, DMA rapidly dispersed while MMA and inorganic As remained close to the entry point. Germanic acid addition did not affect grain As in arsenite-treated panicles. Three-dimensional SXRF microtomography gave further information on arsenite localization in the ovular vascular trace (OVT) of rice grains. These results demonstrate that inorganic As is poorly remobilized, while organic species are readily remobilized, from leaves to grain. Stem translocation of inorganic As may not rely solely on silicic acid transporters.

  19. Phloem transport of arsenic species from flag leaf to grain during grain filling

    SciTech Connect (OSTI)

    Carey, Anne-Marie; Norton, Gareth J.; Deacon, Claire; Scheckel, Kirk G.; Lombi, Enzo; Punshon, Tracy; Guerinot, Mary Lou; Lanzirotti, Antonio; Newville, Matt; Choi, Yongseong; Price, Adam H.; Meharg, Andrew A.

    2011-09-20

    Strategies to reduce arsenic (As) in rice grain, below concentrations that represent a serious human health concern, require that the mechanisms of As accumulation within grain be established. Therefore, retranslocation of As species from flag leaves into filling rice grain was investigated. Arsenic species were delivered through cut flag leaves during grain fill. Spatial unloading within grains was investigated using synchrotron X-ray fluorescence (SXRF) microtomography. Additionally, the effect of germanic acid (a silicic acid analog) on grain As accumulation in arsenite-treated panicles was examined. Dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) were extremely efficiently retranslocated from flag leaves to rice grain; arsenate was poorly retranslocated, and was rapidly reduced to arsenite within flag leaves; arsenite displayed no retranslocation. Within grains, DMA rapidly dispersed while MMA and inorganic As remained close to the entry point. Germanic acid addition did not affect grain As in arsenite-treated panicles. Three-dimensional SXRF microtomography gave further information on arsenite localization in the ovular vascular trace (OVT) of rice grains. These results demonstrate that inorganic As is poorly remobilized, while organic species are readily remobilized, from leaves to grain. Stem translocation of inorganic As may not rely solely on silicic acid transporters.

  20. Increasing the Consumption of Whole Grain Foods in School Meals 

    E-Print Network [OSTI]

    Warren, Cynthia Ann

    2011-08-08

    Current national dietary policy recommends that half, or three, of the six daily servings of grain foods be consumed as whole grains. However, most American children prefer to consume enriched, refined over whole grains. ...

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

    SciTech Connect (OSTI)

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

    2014-11-01

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

  2. Changing Supply of Grains in Texas. 

    E-Print Network [OSTI]

    Moore, Clarence A.; Whitney, Howard S.

    1959-01-01

    importance, while rice in- creased, in the food grain group in the 1950's. Grain sorghum increased from 21 percent of total feed grain production in 1935-39 to 72 percent in 1955-58, while corn decreased from 52 to 14 per- cent. Texas usually grows more... for food. This indi- cates a greater dependence on export markets to take the increased production in recent years. Although Texas grows an average of 43,000,- 000 bushels of wheat annually, this makes up only a relatively small proportion of total U...

  3. Conglomeration of kilometre-sized planetesimals

    E-Print Network [OSTI]

    Shannon, Andrew; Wu, Yanqin; Lithwick, Yoram

    2015-02-25

    out of ? 104M? of primordial solids. The total disk mass, if supplemented with the missing hydro- gen gas, would then reach of order a solar mass. This is very surprising and, in our view, invalidates the low-efficiency conglomeration model. Moreover... . This corresponds to a dis- ruption velocity of v ? 100 cm/ s, or e ? 10?3 at 40 AU. When bodies of size s1 are catastrophically disrupted, we re-distribute their masses to smaller size bins with a number distribution that is power-law in size, dn/ds ? sq? for s < s...

  4. Suppression of Grain Boundaries in Graphene Growth on Superstructured...

    Office of Scientific and Technical Information (OSTI)

    Suppression of Grain Boundaries in Graphene Growth on Superstructured Mn-Cu(111) Surface Prev Next Title: Suppression of Grain Boundaries in Graphene Growth on...

  5. Synthesis of ultrafine grain ferrites 

    E-Print Network [OSTI]

    Livingston, Terry Wayne

    1988-01-01

    , Ti(OCsH, t)s, to form the perovskite SrTiOs, which had a high specific surface area. They reported a high degree of control over the purity, mixing uniformity and crystallite size demonstrating the value of the alkoxide approach. The sol-gel method... by heat treatment. ' Murayma and kfeguro (1971) have prepared, by the soi-gel method, posvders of mixed oxides of Al -r Si, Al + Ti, and Si + Ti. They did this through hydrolysis of Al(OCs Hs)s, Si(OCzHs)4, and Ti(OCsHs)4. These powders of complex...

  6. Grain in weakly ionized plasma in the presence of an external magnetic field: Charging by plasma currents and effective potential

    SciTech Connect (OSTI)

    Momot, A. I.; M.M. Bogolubov Institute for Theoretical Physics, Nat. Acad. Sci. of Ukraine, 14b, Metrologichna Str., Kyiv, 03680

    2013-07-15

    The problem of grain screening is solved numerically for the case of weakly ionized plasma in the presence of an external magnetic field. The plasma dynamics is described within the drift-diffusion approximation under the assumption that the grain absorbs all encountered electrons and ions. We also assume that the plasma current through the grain surface is equal to zero in the stationary state. This condition is used to perform self-consistent calculations of the grain charge. The spatial distribution of the screened grain potential is studied and compared with the analytical estimates. It is shown that at the distances larger than the Debye length such potential has the Coulomb-like asymptotics with the effective charge dependent on the angle between the radius vector and the external magnetic field direction. The numerical solutions show that in the direction parallel to the external magnetic field the effective potential can have nonmonotonic behavior.

  7. The relationship between grain boundary structure, defect mobility, and grain boundary sink efficiency

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

    Uberuaga, Blas Pedro; Vernon, Louis J.; Martinez, Enrique; Voter, Arthur F.

    2015-03-13

    Nanocrystalline materials have received great attention due to their potential for improved functionality and have been proposed for extreme environments where the interfaces are expected to promote radiation tolerance. However, the precise role of the interfaces in modifying defect behavior is unclear. Using long-time simulations methods, we determine the mobility of defects and defect clusters at grain boundaries in Cu. We find that mobilities vary significantly with boundary structure and cluster size, with larger clusters exhibiting reduced mobility, and that interface sink efficiency depends on the kinetics of defects within the interface via the in-boundary annihilation rate of defects. Thus,more »sink efficiency is a strong function of defect mobility, which depends on boundary structure, a property that evolves with time. Further, defect mobility at boundaries can be slower than in the bulk, which has general implications for the properties of polycrystalline materials. Finally, we correlate defect energetics with the volumes of atomic sites at the boundary.« less

  8. Correcting Iron Deficiencies in Grain Sorghum 

    E-Print Network [OSTI]

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

    1996-02-20

    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....

  9. PRE-PRECIPITATION PHENOMENA AT GRAIN BOUNDARIES

    E-Print Network [OSTI]

    Briceno-Valero, J.

    2010-01-01

    13820 DE82 0 1 2 7 9 4 PRE-PRECIPITATION PHENOMENA AT GRAINof any evidence suggesting precipitation has occurred. Theand grain boundary precipitation have shown (1) that there

  10. Micro-PIXE measurement of Ni distribution over supported nickel oxide catalyst

    SciTech Connect (OSTI)

    Ahmed, M.; Rahman, A.; Nickel, J. [King Fahd Univ., Dhahran (Saudi Arabia)] [and others

    1994-12-31

    Supported nickel oxide catalysts have a wide range of applications in petrochemical industry. This work reports the results of a micro-PIXE measurement of Ni distribution in a supported nickel oxide catalyst over individual silica base particles, 60-200 {mu}m in size. These catalysts were synthesized with 1% and 5% then calcined at 400 {degrees}C. A 2.5 MeV proton microbeam was used to scan the samples of individual grains. Two dimensional distribution maps of Ni and Si have been measured. This paper discusses the important effects of the process of calcination on the distribution of Ni. The effects of different nickel loading and other synthesis conditions will also be discussed.

  11. Comment on "Minimal size of a barchan dune"

    E-Print Network [OSTI]

    B. Andreotti; P. Claudin

    2007-05-24

    It is now an accepted fact that the size at which dunes form from a flat sand bed as well as their `minimal size' scales on the flux saturation length. This length is by definition the relaxation length of the slowest mode toward equilibrium transport. The model presented by Parteli, Duran and Herrmann [Phys. Rev. E 75, 011301 (2007)] predicts that the saturation length decreases to zero as the inverse of the wind shear stress far from the threshold. We first show that their model is not self-consistent: even under large wind, the relaxation rate is limited by grain inertia and thus can not decrease to zero. A key argument presented by these authors comes from the discussion of the typical dune wavelength on Mars (650 m) on the basis of which they refute the scaling of the dune size with the drag length evidenced by Claudin and Andreotti [Earth Pla. Sci. Lett. 252, 30 (2006)]. They instead propose that Martian dunes, composed of large grains (500 micrometers), were formed in the past under very strong winds. We show that this saltating grain size, estimated from thermal diffusion measurements, is not reliable. Moreover, the microscopic photographs taken by the rovers on Martian aeolian bedforms show a grain size of 87 plus or minus 25 micrometers together with hematite spherules at millimetre scale. As those so-called ``blueberries'' can not be entrained by reasonable winds, we conclude that the saltating grains on Mars are the small ones, which gives a second strong argument against the model of Parteli et al.

  12. Microstructure and mechanical behavior of neutron irradiated ultrafine grained ferritic steel

    SciTech Connect (OSTI)

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

    2014-10-01

    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.

  13. Single and large grain activities at Fermilab

    SciTech Connect (OSTI)

    Antoine, Claire; /Fermilab

    2006-01-01

    This paper describes the ongoing activities at Fermilab for large grains and monocrystalline niobium. In addition to acquisition of local fabrication expertise, we plan to develop an R&D program dedicated to evidence the possible influence of crystal orientation on physical and chemical properties of niobium, such as mechanical properties, magnetic properties or surface contamination. Some considerations are also given about the morphology at grain boundaries and its role on the behavior of superconducting cavities.

  14. Fine-grained Photovoltaic Output Prediction using a Bayesian Ensemble Prithwish Chakraborty1,2

    E-Print Network [OSTI]

    Ramakrishnan, Naren

    Fine-grained Photovoltaic Output Prediction using a Bayesian Ensemble Prithwish Chakraborty1 Increasingly, local and distributed power generation e.g., through solar (photovoltaic or PV), wind, fuel cells. However, renewable power sources such as photovoltaic (PV) arrays and wind are both variable

  15. Grain Sorghum Varieties in Texas. 

    E-Print Network [OSTI]

    Karper, R. E. (Robert Earl)

    1932-01-01

    Station in 1920 (Fig. 8). Texas Blackhul kafir is a pure line selection of Blackhul that is inter- mediate in height between Standard and Dwarf, has a slender stalk with 15 leaves, and is as early as Dawn kafir. This is a desir- able pure line variety... of kafir developed and distributed from the Lubbock Station in 1925 (Fig. 7). Dawn kafir arose at the U. S. Field Station at Amarillo, Tex- as, in 1907 and was selected by A. H. Leidigh in the progeny of what was apparently a kafir- sorgo hybrid...

  16. Effects of grain deterioration on sorghum food quality 

    E-Print Network [OSTI]

    Domanski, Cristian Estanislao

    1983-01-01

    Sorghum Cultivars. . . . . . . . . . . . . . . . . . 68 LIST OF FIGURES FIGURE Page 1 Effect o grain deterioration on test weight of 77CS5 sorghum samples. . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2 Effect of grain deterioration... on thousand kernel weight of 77CSS sorghum samples. 28 3 Effect of grain deterioration on test weight of CS3541 sorghum samples. 31 4 Effect of grain deterioration on thousand kernel weight of CS3541 sorghum samples. 32 5 Effect of grain deterioration...

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

    SciTech Connect (OSTI)

    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)

    2013-10-10

    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.

  18. Synchrotron characterization of nanograined UO2 grain growth

    SciTech Connect (OSTI)

    Mo, Kun; Miao, Yinbin; Yun, Di; Jamison, Laura M.; Lian, Jie; Yao, Tiankei

    2015-09-30

    This activity is supported by the US Nuclear Energy Advanced Modeling and Simulation (NEAMS) Fuels Product Line (FPL) and aims at providing experimental data for the validation of the mesoscale simulation code MARMOT. MARMOT is a mesoscale multiphysics code that predicts the coevolution of microstructure and properties within reactor fuel during its lifetime in the reactor. It is an important component of the Moose-Bison-Marmot (MBM) code suite that has been developed by Idaho National Laboratory (INL) to enable next generation fuel performance modeling capability as part of the NEAMS Program FPL. In order to ensure the accuracy of the microstructure based materials models being developed within the MARMOT code, extensive validation efforts must be carried out. In this report, we summarize our preliminary synchrotron radiation experiments at APS to determine the grain size of nanograin UO2. The methodology and experimental setup developed in this experiment can directly apply to the proposed in-situ grain growth measurements. The investigation of the grain growth kinetics was conducted based on isothermal annealing and grain growth characterization as functions of duration and temperature. The kinetic parameters such as activation energy for grain growth for UO2 with different stoichiometry are obtained and compared with molecular dynamics (MD) simulations.

  19. Geophysical Research Abstracts, Vol. 11, EGU2009-0, 2009

    E-Print Network [OSTI]

    is characteristic for chemically induced grain boundary migration, strong crystal plasticity and possible analysis involving crystal size distribution, grain boundary statistics and grain shapes analyses

  20. Does the debris disk around HD 32297 contain cometary grains?

    SciTech Connect (OSTI)

    Rodigas, Timothy J.; Hinz, Philip M.; Bailey, Vanessa; Defrere, Denis; Leisenring, Jarron; Schneider, Glenn; Skemer, Andrew J.; Vaitheeswaran, Vidhya; Debes, John H.; Mamajek, Eric E.; Pecaut, Mark J.; Currie, Thayne; De Rosa, Robert J.; Ward-Duong, Kimberly; Hill, John M.; Skrutskie, Michael

    2014-03-01

    We present an adaptive optics imaging detection of the HD 32297 debris disk at L' (3.8 ?m) obtained with the LBTI/LMIRcam infrared instrument at the Large Binocular Telescope. The disk is detected at signal-to-noise ratio per resolution element ?3-7.5 from ?0.''3 to 1.''1 (30-120 AU). The disk at L' is bowed, as was seen at shorter wavelengths. This likely indicates that the disk is not perfectly edge-on and contains highly forward-scattering grains. Interior to ?50 AU, the surface brightness at L' rises sharply on both sides of the disk, which was also previously seen at Ks band. This evidence together points to the disk containing a second inner component located at ?50 AU. Comparing the color of the outer (50 grains model of Donaldson et al. We find that the model fails to match this disk's surface brightness and spectrum simultaneously (reduced chi-square = 17.9). When we modify the density distribution of the model disk, we obtain a better overall fit (reduced chi-square = 2.87). The best fit to all of the data is a pure water ice model (reduced chi-square = 1.06), but additional resolved imaging at 3.1 ?m is necessary to constrain how much (if any) water ice exists in the disk, which can then help refine the originally proposed cometary grains model.

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

    SciTech Connect (OSTI)

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

    2006-10-31

    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.

  2. Strengthening of metallic alloys with nanometer-size oxide dispersions

    DOE Patents [OSTI]

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

    1999-06-01

    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.

  3. Strengthening of metallic alloys with nanometer-size oxide dispersions

    DOE Patents [OSTI]

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

    1999-01-01

    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.

  4. Popped sorghum grain for finishing beef cattle 

    E-Print Network [OSTI]

    Adame de Leon, Jose Luis

    1968-01-01

    POPPED SORGHUM GRAIN FOR FINISHING BEEF CATTLE A Thesis By JOSE LUIS ADAME DE LEON Submitted to the Graduate Col. lege of the Texas A@M University in Ioartial fulfillment of the requirements for the degree of MA ST ER OF SCIEN C E January... 196B Major Subject: Animal Production POPPED SORGHUM GRAIN FOR FINISHING B E EF CA T T LE A Thesis By JOSE LUIS ADAME DE LEON Approved as to style and content by: I / j (C irman of Committee (Member) )j5 (Head of Department) (Merp er...

  5. Grain Sorghums Versus Corn for Fattening Lambs 

    E-Print Network [OSTI]

    Jones, J. M. (John McKinley); Brewer, Roy A.

    1922-01-01

    she reach first place in the production of sheep. At the same time an increasing West Texas acreage is being planted in grain sor- ghums during each succeeding year, and the farmers producing these crops are demanding information and assistance... producing 60,000,000 bushels of the grain sor- ghums. This is conceded to be only a partial showing of the possible production because the area planted in them is limited to the popular annual estimate of the farmers as to how much production the market...

  6. Equal Channel Angular Pressing (ECAP) and Its Application to Grain Refinement of Al-Zn-Mg-Cu Alloy

    SciTech Connect (OSTI)

    Tekeli, Sueleyman; Gueral, Ahmet

    2011-12-10

    Microstructure of a metal can be considerably changed by severe plastic deformation techniques such as high pressure torsion, extrusion and equal-channel angular pressing (ECAP). Among these methods, ECAP is particularly attractive because it has a potential for introducing significant grain refinement and homogeneous microstructure into bulk materials. Typically, it reduces the grain size to the submicrometer level or even nanometer range and thus produces materials that are capable of exhibiting unusual mechanical properties. In the present study, a test unites for equal channel angular pressing was constructed and this system was used for Al-Zn-Mg-Cu alloy. After the optimization tests, it was seen that the most effective lubricant for the dies was MoS{sub 2}, the pressing pressure was around 25-35 ton and the pressing speed was 2 mm/s. By using these parameters, the Al-Zn-Mg-Cu alloy was successfully ECAPed up to 14 passes at 200 deg. C using route C. After ECAP tests, the specimens were characterized by transmission electron microscope (TEM), hardness and macrostructural investigations. It was seen that the plastic deformation in the ECAPed specimens occurred from edge to the centre like whirlpool. In addition, the deformation intensity increased with increasing pass number. The grain size of the specimens effectively also decreased with increasing pass number. That is, while the grain size of unECAPed specimen was 10 {mu}m, this value decreased to 300 nm after 14 passes. At the beginning, while there was a banding tendency in the grains toward deformation direction, homogeneous and equiaxed grains were formed with increasing pass number. This grain refinement was as a result of an interaction between shear strain and thermal recovery during ECAP processing. Hardness measurements showed that the hardness values increased up to 4 passes, decreased effectively at 6th pass, again increased at 8th pass and after this pass, the hardness again decreased due to dynamic recrystallization.

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

    E-Print Network [OSTI]

    Acep Purqon; Sparisoma Viridi

    2014-11-01

    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.

  8. LAMINAR: PRACTICAL FINE-GRAINED DECENTRALIZED INFORMATION

    E-Print Network [OSTI]

    Witchel, Emmett

    LAMINAR: PRACTICAL FINE-GRAINED DECENTRALIZED INFORMATION FLOW CONTROL (DIFC) Indrajit Roy, Donald} {} Information flow in a lattice #12;In this talk: Laminar A practical way to provide end-to-end security guarantees. #12;Outline Comparison with current DIFC systems Laminar: programming model Design: PL + OS

  9. Oklahoma Small Grains Variety Performance Tests

    E-Print Network [OSTI]

    Balasundaram, Balabhaskar "Baski"

    Oklahoma Small Grains Variety Performance Tests 2012 - 2013 J.T. Edwards R.D. Kochenower R provided by: Oklahoma Wheat Commission Oklahoma Wheat Research Foundation OSU Cooperative Extension Service Central Research Station, Lahoma Lawrence Bohl, Oklahoma Panhandle Research and Extension Center, Goodwell

  10. Large grain cavities from pure niobium ingot

    DOE Patents [OSTI]

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

    2012-03-06

    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.

  11. Extractability Profiling and Antioxidant Activity of Flavonoids in Sorghum Grain and Non-grain Materials 

    E-Print Network [OSTI]

    Njongmeta, Nenge Lynda A.

    2010-07-14

    Grains, leaves, sheaths, glumes and stalks of sorghum varieties were analyzed for total phenols, condensed tannins, flavan-4-ols, anthocyanins and in vitro antioxidant activity. Black sorghum bran was used to evaluate the effectiveness of organic...

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

    E-Print Network [OSTI]

    Baram, J.

    2011-01-01

    but only after some extent of plastic deformation, It can,The Inhomogeneity of Plastic Deformation, A.S.M. Seminar,EMISSION GENERATED DURING PLASTIC DEFORMATION OF COPPER J,

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

    E-Print Network [OSTI]

    Baram, J.

    2013-01-01

    EMISSION GENERATED DURING PLASTIC DEFORMATION OF ALUMINUMEMISSION GENERATED DURING PLASTIC DEFORMATION OF ALUMINUM J.Al 1100 samples during plastic deformation were analyzed

  14. Grain size dependence of fracture toughness and crack-growth resistance of superelastic NiTi

    E-Print Network [OSTI]

    Sun, Qing-Ping

    Available online xxxx Keywords: Shape memory alloys Martensitic phase transformation Microstructure to a reversible martensitic phase transformation (PT), superelastic (SE) NiTi shape memory alloys (SMAs with thickness of 1.7 mm were sandwiched in stainless steel sheets and were cold-rolled to 42% of thickness

  15. Grain size-dependent viscosity convection and the thermal evolution of the Earth

    E-Print Network [OSTI]

    follow the heat production rate. Early models of the thermal evolution of the Earth found and that the present-day heat loss rate exceeds the heat generation rate by about 10% [2]. The excess heat loss rate. The Earth can either quickly forget the initial conditions with temperature and heat loss following

  16. Anisotropic mobility in large grain size solution processed organic semiconductor thin films

    E-Print Network [OSTI]

    Sansoz, Frederic

    , University of Vermont, Burlington, Vermont 05405, USA 2 School of Engineering and Materials Science Program, University of Vermont, Burlington, Vermont 05405, USA 3 Department of Chemistry, University of Kentucky

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

    E-Print Network [OSTI]

    Detor, Andrew J. (Andrew Joseph)

    2007-01-01

    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 ...

  18. Does size matter?

    SciTech Connect (OSTI)

    Carreras, B. A.; Physics Department, College of Natural Science and Mathematics and Geophysical Institute, University of Alaska, Fairbanks, Alaska 99775; Physics Department, Universidad Carlos III de Madrid, Madrid ; Newman, D. E.; Dobson, Ian

    2014-06-15

    Failures of the complex infrastructures society depends on having enormous human and economic cost that poses the question: Are there ways to optimize these systems to reduce the risks of failure? A dynamic model of one such system, the power transmission grid, is used to investigate the risk from failure as a function of the system size. It is found that there appears to be optimal sizes for such networks where the risk of failure is balanced by the benefit given by the size.

  19. MESOSCALE THEORY OF GRAINS AND CELLS: POLYCRYSTALS & PLASTICITY

    E-Print Network [OSTI]

    Sethna, James P.

    MESOSCALE THEORY OF GRAINS AND CELLS: POLYCRYSTALS & PLASTICITY A Dissertation Presented RIGHTS RESERVED #12;MESOSCALE THEORY OF GRAINS AND CELLS: POLYCRYSTALS & PLASTICITY Surachate Limkumnerd, continuum explanation for the evolution of dislocations into sharp walls. We present here a mesoscale theory

  20. INVESTIGATION OF PRESOLAR SILICATE GRAINS FROM ENSTATITE CHONDRITES.

    E-Print Network [OSTI]

    in SAH 97159 and six of the eight grains in SAH 97096 are 17 O-rich and belong to group 1, with likely eight O-anomalous grains each in SAH 97159 and SAH 97096, but none from Qingzhen. All eight grains are 18 O-rich and belong to group 4. One grain in SAH 97096 has a 17 O/16 O ratio of 134±1 (�10

  1. Fire Size in Tunnels 

    E-Print Network [OSTI]

    Carvel, Ricky O

    In recent years, a number of high profile accidental fires have occurred in several road and rail tunnels throughout the world. Many of these fires grew rapidly to catastrophic size and claimed many lives. The processes ...

  2. Coarse-grained distinguishability of field interactions

    E-Print Network [OSTI]

    Bény, Cédric

    2015-01-01

    Information-theoretical quantities such as statistical distinguishability typically result from optimisations over all conceivable observables. Physical theories, however, are not generally considered valid for all mathematically allowed measurements. For instance, quantum field theories are not meant to be correct or even consistent at arbitrarily small lengthscales. A general way of limiting such an optimisation to certain observables is to first coarse-grain the states by a quantum channel. We show how to calculate contractive quantum information metrics on coarse-grained equilibrium states of free bosonic systems (Gaussian states), in directions generated by arbitrary perturbations of the Hamiltonian. As an example, we study the Klein-Gordon field. If the phase-space resolution is coarse compared to h-bar, the various metrics become equal and the calculations simplify. In that context, we compute the scale dependence of the distinguishability of the quartic interaction.

  3. Coarse-grained distinguishability of field interactions

    E-Print Network [OSTI]

    Cédric Bény

    2015-09-10

    Information-theoretical quantities such as statistical distinguishability typically result from optimisations over all conceivable observables. Physical theories, however, are not generally considered valid for all mathematically allowed measurements. For instance, quantum field theories are not meant to be correct or even consistent at arbitrarily small lengthscales. A general way of limiting such an optimisation to certain observables is to first coarse-grain the states by a quantum channel. We show how to calculate contractive quantum information metrics on coarse-grained equilibrium states of free bosonic systems (Gaussian states), in directions generated by arbitrary perturbations of the Hamiltonian. As an example, we study the Klein-Gordon field. If the phase-space resolution is coarse compared to h-bar, the various metrics become equal and the calculations simplify. In that context, we compute the scale dependence of the distinguishability of the quartic interaction.

  4. UNCORRECTED 2 The influence of grains' crystallographic orientations on advancing

    E-Print Network [OSTI]

    Cizelj, Leon

    grain geometry and crystallographic orientations is coupled with 10 crystal plasticity constitutive; Polycrystalline material; Crystal plasticity 20 21 1. Introduction 22 Microstructurally short cracks behave works use rectangular grain 39shapes [10,11]. Random grain geometry and crystal plastic- 40ity have been

  5. RFID BASED GRAIN AND OIL PRODUCTS TRACEABILITY1

    E-Print Network [OSTI]

    Boyer, Edmond

    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

  6. Continuous fine-grained arm action recognition using motion spectrum

    E-Print Network [OSTI]

    Continuous fine-grained arm action recognition using motion spectrum mixture models Xi Zhao, it is necessary to recognise the fine-grained arm action during user interactions with other people or objects. A method to recognise a set of arm actions on a fine-grained level (e.g. checking the wristband, drinking

  7. Synthesis of fine-grained TATB

    DOE Patents [OSTI]

    Lee, Kien-Yin (Santa Fe, NM); Kennedy, James E. (Santa Fe, NM)

    2003-04-15

    A method for producing fine-grained triamino-trinitrobenzene (TATB) powders having improved detonation-spreading performance and hence increased shock sensitivity when compared with that for ultrafine TATB is described. A single-step, sonochemical amination of trichloro-trinitrobenzene using ammonium hydroxide solution in a sealed vessel yields TATB having approximately 6 .mu.m median particle diameter and increased shock sensitivity.

  8. 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)

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

    2014-04-07

    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 Research’s 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 (NMHC’s) 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.

  9. International trade in grains and cotton: a market share-Markov chain analysis 

    E-Print Network [OSTI]

    Seelig, Leonard Robert

    1980-01-01

    o p ment May 1980 ABSTRACT International Trade in Grains and Cotton: A Market Share - Markov Chain Analysis May 1980 Leonard Robert Seeli g, B . Com . , University of the Wi twatersand, South Africa Chairman of Advisory Committee: Dr. Michael... the relative trade positions of each country fn the market, market shares give some indication of the potential market power of individual trading nations. Markov Chain Analysis was used to project the probability distribution of the export of selected...

  10. Sizing and burn time measurements of micron-sized metal powders

    SciTech Connect (OSTI)

    Gill, Robert J.; Mohan, Salil; Dreizin, Edward L. [New Jersey Institute of Technology Newark, New Jersey 07102 (United States)

    2009-06-15

    Detailed ignition and combustion mechanisms are needed to develop optimized propellant and energetic formulations using micron-sized metal powders, such as aluminum. Combustion researchers have traditionally used relatively coarse metal particles to characterize the burn time dependence on particle size. However, measurements of burn times for particles below 10 {mu}m in diameter are still needed for aluminum powders and other metal fuels. The apparatus described here sizes the particles just before the ignition event, providing a direct correlation between individual particle size and its burn time. Two lasers were utilized: a 785 nm laser diode for sizing the particles and a 125 W CO{sub 2} laser for particle ignition. The particles crossed the 785 nm laser beam just before crossing the CO{sub 2} laser beam. The particle size was determined from the amplitude of the scattered 785 nm light pulse. The burn time was determined from the duration of the visible light emission produced from the ignited particle. The in situ measured particle size distributions compared well with the size distributions measured for the same powders by a commercial instrument using low angle laser light scattering. Our measurements with two nominally spherical aluminum powders, suggest that the burn times increase from 0.5 to {approx}2.5 ms as the particle diameters increase from 3 to 8 {mu}m.

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

    SciTech Connect (OSTI)

    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)

    2014-05-07

    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.

  12. NanoSIMS, TEM, and XANES studies of a unique presolar supernova graphite grain

    SciTech Connect (OSTI)

    Groopman, Evan; Bernatowicz, Thomas; Zinner, Ernst; Nittler, Larry R.

    2014-07-20

    We report on isotopic and microstructural investigations of a unique presolar supernova (SN) graphite grain, referred to as G6, isolated from the Orgueil CI chondrite. G6 contains complex heterogeneities in its isotopic composition and in its microstructure. Nano-scale secondary ion mass spectrometer isotope images of ultramicrotome sections reveal heterogeneities in its C, N, and O isotopic compositions, including anomalous shell-like structures. Transmission electron microscope studies reveal a nanocrystalline core surrounded by a turbostratic graphite mantle, the first reported nanocrystalline core from a low-density SN graphite grain. Electron diffraction analysis shows that the nanocrystalline core consists of randomly oriented 2-4 nm graphene particles, similar to those in cores of high-density (HD) presolar graphite grains from asymptotic giant branch stars. G6's core also exhibits evidence for planar stacking of these graphene nano-sheets with a domain size up to 4.5 nm, which was unobserved in the nanocrystalline cores of HD graphite grains. We also report on X-ray absorption near-edge structure measurements of G6. The complex isotopic- and micro-structure of G6 provides evidence for mixing and/or granular transport in SN ejecta.

  13. Distributed Estimation Distributed Estimation

    E-Print Network [OSTI]

    Gupta, Vijay

    with a Star Topology 2 2.1 Static Sensor Fusion . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1.1 Combining Estimators . . . . . . . . . . . . . . . . . . . . 3 2.1.2 Static Sensor Fusion for Star Topology;Distributed Estimation 3 Non-Ideal Networks with Star Topology 10 3.1 Sensor Fusion in Presence of Message

  14. Angular Size in a Static Universe

    E-Print Network [OSTI]

    David F. Crawford

    1994-07-11

    In principle the geometry of the universe can be investigated by measuring the angular size of known objects as a function of distance. Thus the distribution of angular sizes provides a critical test of the stable and static model of the universe described by Crawford (1991,1993) that has a simple and explicit relationship between the angular size of an object and its redshift. The result is that the agreement with observations of galactic diameters and the size of double radio sources with the static model is much better than the standard (Big Bang) theory without evolution. However there is still a small discrepancy at large redshifts that could be due to selection effects.

  15. Profits and Losses from On-farm Drying and Storage of Grain Sorghum in Central Texas and the Coastal Bend. 

    E-Print Network [OSTI]

    Hildreth, R. J.; Moore, C. A.

    1958-01-01

    AND STORAGE OF GRAIN SORGHUM FOR UNITS OF SELECTED SIZE AND TYPE - - Item Round bin Quonset type Dimensions Capacity1 2-2,200 bushel 1-32 x 60 bins building 2.274 cwt. 7.815 cwt. Annual costs --- Dollars - - - Depreciation on structure, fans, grain...' . 'N @ and Storage. of < 4 GJ@$& A. .-+-%aL in Central Texas and tte Coastal Bend TEXAS AGRICULTURAL EXPERIMENT STATION R. D. LEWIS. DIRECTOR. COLLEGE STATION. TEXAS IN COOPERATION WITH THE UNITED STATES DEPARTMENT OF AGRICULTURE SUMMARY...

  16. A course-grained model for polyethylene glycol polymer

    SciTech Connect (OSTI)

    Nicholson, Don M [ORNL; Wang, Qifei [ORNL; Keffer, David J [ORNL

    2011-01-01

    A coarse-grained (CG) model of polyethylene glycol (PEG) was developed and implemented in CG molecular dynamics (MD) simulations of PEG chains with degree of polymerization (DP) 20 and 40. In the model, two repeat units of PEG are grouped as one CG bead. Atomistic MD simulation of PEG chains with DP = 20 was first conducted to obtain the bonded structural probability distribution functions (PDFs) and nonbonded pair correlation function (PCF) of the CG beads. The bonded CG potentials are obtained by simple inversion of the corresponding PDFs. The CG nonbonded potential is parameterized to the PCF using both an inversion procedure based on the Ornstein-Zernike equation with the Percus-Yevick approximation (OZPY{sup -1}) and a combination of OZPY{sup -1} with the iterative Boltzmann inversion (IBI) method (OZPY{sup -1}+IBI). As a simple one step method, the OZPY{sup -1} method possesses an advantage in computational efficiency. Using the potential from OZPY{sup -1} as an initial guess, the IBI method shows fast convergence. The coarse-grained molecular dynamics (CGMD) simulations of PEG chains with DP = 20 using potentials from both methods satisfactorily reproduce the structural properties from atomistic MD simulation of the same systems. The OZPY{sup -1}+IBI method yields better agreement than the OZPY{sup -1} method alone. The new CG model and CG potentials from OZPY{sup -1}+IBI method was further tested through CGMD simulation of PEG with DP = 40 system. No significant changes are observed in the comparison of PCFs from CGMD simulations of PEG with DP = 20 and 40 systems indicating that the potential is independent of chain length.

  17. Measurements of stress fields near a grain boundary: Exploring blocked arrays of dislocations in 3D

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

    Guo, Y.; Collins, D. M.; Tarleton, E.; Hofmann, F.; Tischler, J.; Liu, W.; Xu, R.; Wilkinson, A. J.; Britton, T. B.

    2015-06-24

    The interaction between dislocation pile-ups and grain boundaries gives rise to heterogeneous stress distributions when a structural metal is subjected to mechanical loading. Such stress heterogeneity leads to preferential sites for damage nucleation and therefore is intrinsically linked to the strength and ductility of polycrystalline metals. To date the majority of conclusions have been drawn from 2D experimental investigations at the sample surface, allowing only incomplete observations. Our purpose here is to significantly advance the understanding of such problems by providing quantitative measurements of the effects of dislocation pile up and grain boundary interactions in 3D. This is accomplished throughmore »the application of differential aperture X-ray Laue micro-diffraction (DAXM) and high angular resolution electron backscatter diffraction (HR-EBSD) techniques. Our analysis demonstrates a similar strain characterization capability between DAXM and HR-EBSD and the variation of stress intensity in 3D reveals that different parts of the same grain boundary may have different strengths in resisting slip transfer, likely due to the local grain boundary curvature.« less

  18. 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 Center Home Page on QA:QAsource History View NewTexas: Energy Resources Jump to: navigation, search Equivalent|Corn Products JumpGrain

  19. 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 Center Home Page on QA:QAsource History ViewMayo, Maryland: Energy ResourcesDec 2005 WindPRO isMickeyWestNewOhio:MidstateCity,Grain

  20. identification Distributed

    E-Print Network [OSTI]

    Schenato, Luca

    Networked Control Systems Clock Sync Channel identification in WSN Distributed control of Smart. Sandro Zampieri #12;Networked Control Systems Clock Sync Channel identification in WSN Distributed Systems Clock Sync Channel identification in WSN Distributed control of Smart Grids Conclusions Issues

  1. Control of pore size in epoxy systems.

    SciTech Connect (OSTI)

    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.

    2009-01-01

    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.

  2. Uniform Distribution

    E-Print Network [OSTI]

    randomly and equally likely a point in that interval), the uniform distribution ... Roughly speaking, this means that from any distribution we can create the uniform.

  3. Magnetic agglomeration method for size control in the synthesis of magnetic nanoparticles

    DOE Patents [OSTI]

    Huber, Dale L. (Albuquerque, NM)

    2011-07-05

    A method for controlling the size of chemically synthesized magnetic nanoparticles that employs magnetic interaction between particles to control particle size and does not rely on conventional kinetic control of the reaction to control particle size. The particles are caused to reversibly agglomerate and precipitate from solution; the size at which this occurs can be well controlled to provide a very narrow particle size distribution. The size of particles is controllable by the size of the surfactant employed in the process; controlling the size of the surfactant allows magnetic control of the agglomeration and precipitation processes. Agglomeration is used to effectively stop particle growth to provide a very narrow range of particle sizes.

  4. Local gauge theory and coarse graining

    E-Print Network [OSTI]

    Jose A. Zapata

    2012-03-11

    Within the discrete gauge theory which is the basis of spin foam models, the problem of macroscopically faithful coarse graining is studied. Macroscopic data is identified; it contains the holonomy evaluation along a discrete set of loops and the homotopy classes of certain maps. When two configurations share this data they are related by a local deformation. The interpretation is that such configurations differ by "microscopic details". In many cases the homotopy type of the relevant maps is trivial for every connection; two important cases in which the homotopy data is composed by a set of integer numbers are: (i) a two dimensional base manifold and structure group U(1), (ii) a four dimensional base manifold and structure group SU(2). These cases are relevant for spin foam models of two dimensional gravity and four dimensional gravity respectively. This result suggests that if spin foam models for two-dimensional and four-dimensional gravity are modified to include all the relevant macroscopic degrees of freedom -the complete collection of macroscopic variables necessary to ensure faithful coarse graining-, then they could provide appropriate effective theories at a given scale.

  5. Contrasting size evolution in marine and freshwater diatoms

    E-Print Network [OSTI]

    carbon cycle and most aquatic ecosystems. Their cell sizes impact carbon sequestration and en- ergy carbon cycle and the structure and functioning of aquatic ecosystems. evolutionarily stable strategy and forming the basis of many aquatic food webs (6). Diatom size distributions greatly influence carbon

  6. Sample sizes for confidence limits for reliability.

    SciTech Connect (OSTI)

    Darby, John L.

    2010-02-01

    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.

  7. Dry Heat Processing of Sorghum Grain for Beef Cattle. 

    E-Print Network [OSTI]

    Riggs, J. K.; Sorenson, J. W. Jr.; Hobgood, Price

    1970-01-01

    and popped as it was conveyed a distance of 15.7 feet on the heated-tray surface. The popped- grain mixture was then discharged from the rnach~nr through an unloading spout. Tests were made with this machine to determine the effect of initial grain... - - - ........... - A Machine Operation and Capacity A - - - Bulk Density ............................................. - A - - A - Effect of Grain Moisture Content on - A - .......................... .- A - Popping Characteristics...

  8. Experiences in Large Grain-Single Crystal Cavity Fabrication

    SciTech Connect (OSTI)

    Pekeler, Michael; Schwellenbach, Johannes; Tradt, Marco

    2007-08-09

    At ACCEL instruments several single cell and 9-cell cavities have been produced out of large grain niobium sheets from different suppliers. The fabrication experience and difference to the production out of fine grain niobium sheets will be described. In addition two cavities were produced using single crystal niobium sheets. The final cavities showed no grain boundaries at all in the cavity cell, even not in the electron beam welding seam.

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

    SciTech Connect (OSTI)

    Leonard, T.; Lander, B.; Seifert, U.; Speck, T.

    2013-11-28

    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.

  10. [Perovskite and Fluorite Grain Boundary Properties]. Final Project Report

    SciTech Connect (OSTI)

    Browning, N. D.

    2004-02-24

    One of the main areas of research in the last two years in this program has been the properties of grain boundaries in perovskite and fluorite structure materials.

  11. New Process for Grain Refinement of Aluminum. Final Report

    SciTech Connect (OSTI)

    Dr. Joseph A. Megy

    2000-09-22

    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.

  12. Modeling and Control of Ibuprofen Crystal Growth and Size Distribution

    E-Print Network [OSTI]

    Tran, Anh Tuan

    2015-01-01

    time evolution of coupled chemical reactions. J. Comput.stochastic simulation of chemical kinetics. Annu. Rev. Phys.title for publication in Chemical Engineering Science and is

  13. Concentrations and Size Distributions of Particulate Matter Emissions...

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

    on the Emission Profiles of Trucks and Buses ARB's Study of Emissions from Diesel and CNG Heavy-duty Transit Buses Measurement of Real-World Emissions from Heavy-Duty Diesel...

  14. Modeling and Control of Ibuprofen Crystal Growth and Size Distribution

    E-Print Network [OSTI]

    Tran, Anh Tuan

    2015-01-01

    ethanol and aqueous ethanolic mixtures. In Proceedings of Chemica 2008, pages 1393– 1401, Newcastle, Australia,

  15. Population growth, distribution, and size in Latin America

    E-Print Network [OSTI]

    Lopez-Carr, David

    timber harvesting oil exploration/extraction population growth? degradation of lands in source areas history in Amazonia · Early extractive uses Rubber Forestry #12;Development history in Amazonia forests in the world 2) 45% of all the fresh water on the Earth 3) the planet's largest carbon sink 4

  16. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submitKansasCommunitiesof Energy8) Wigner Home ·theEvenEvidencein turbulent

  17. Barnett Relaxation in Thermally-Rotating Grains

    E-Print Network [OSTI]

    A. Lazarian; W. G. Roberge

    1997-02-16

    We present an exact formulation of the physics of Barnett relaxation. Our formulation is based on a realistic kinetic model of the relaxation mechanism which includes the alignment of the grain angular momentum in body coordinates by Barnett dissipation, disalignment by thermal fluctuations, and coupling of the angular momentum to the gas via gas damping. We solve the Fokker-Planck equation for the measure of internal alignment using numerical integration of the equivalent Langevin equation for Brownian rotation. The accuracy of our results is calibrated by comparing our numerical solutions with exact analytic results obtained for special cases.We describe an analytic approximation for the measure of alignment which fits our numerical results for cases of practical interest.

  18. Method of aeration disinfecting and drying grain in bulk and pretreating seeds and a transverse blow silo grain dryer therefor

    DOE Patents [OSTI]

    Danchenko, Vitaliy G. (Dnipropetrovsk, UA); Noyes, Ronald T. (Stillwater, OK); Potapovych, Larysa P. (Dnipropetrovsk, UA)

    2012-02-28

    Aeration drying and disinfecting grain crops in bulk and pretreating seeds includes passing through a bulk of grain crops and seeds disinfecting and drying agents including an ozone and air mixture and surrounding air, subdividing the disinfecting and drying agents into a plurality of streams spaced from one another in a vertical direction, and passing the streams at different heights through levels located at corresponding heights of the bulk of grain crops and seeds transversely in a substantially horizontal direction.

  19. Edison Job Size Charts

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation Current HABFES Science Network RequirementsEdison ElectrifiesJob Size Charts

  20. Nanodiamond dust and the energy distribution of quasars

    E-Print Network [OSTI]

    L. Binette; A. C. Andersen; H. Mutschke; S. Haro-Corzo

    2005-09-24

    The spectral energy distribution of quasars shows a sharp steepening of the continuum shortward of ~ 1100 A. The steepening could be a result of dust absorption. We present a dust extinction model which considers crystalline carbon grains and compare it with SMC-like dust extinction consisting of a mixture of silicate grains with graphite or amorphous carbon grains. We show that the sharp break seen in individual quasar spectra of intermediate redshif \\~ 1-2 can be reproduced by dust absorption provided the extinction curve consists of nanodiamonds, composed of terrestial cubic diamonds or of diamonds similar to the presolar nanodiamonds found in primitive meteorites.

  1. Nanodiamond dust and the energy distribution of quasars

    E-Print Network [OSTI]

    Binette, L; Mutschke, H; Haro-Corzo, S

    2005-01-01

    The spectral energy distribution of quasars shows a sharp steepening of the continuum shortward of ~ 1100 A. The steepening could be a result of dust absorption. We present a dust extinction model which considers crystalline carbon grains and compare it with SMC-like dust extinction consisting of a mixture of silicate grains with graphite or amorphous carbon grains. We show that the sharp break seen in individual quasar spectra of intermediate redshif \\~ 1-2 can be reproduced by dust absorption provided the extinction curve consists of nanodiamonds, composed of terrestrial cubic diamonds or of diamonds similar to the presolar nanodiamonds found in primitive meteorites.

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

    E-Print Network [OSTI]

    Friedman, Beth

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

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

    SciTech Connect (OSTI)

    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)

    2014-11-01

    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.

  4. Ultrafast visualization of crystallization and grain growth in shock-compressed SiO2

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

    Gleason, A. E.; Bolme, C. A.; Lee, H. J.; Nagler, B.; Galtier, E.; Milathianaki, D.; Hawreliak, J.; Kraus, R. G.; Eggert, J. H.; Fratanduono, D. E.; et al

    2015-09-04

    Pressure- and temperature-induced phase transitions have been studied for more than a century but very little is known about the non-equilibrium processes by which the atoms rearrange. Shock compression generates a nearly instantaneous propagating high-pressure/temperature condition while in situ X-ray diffraction (XRD) probes the time-dependent atomic arrangement. Here we present in situ pump–probe XRD measurements on shock-compressed fused silica, revealing an amorphous to crystalline high-pressure stishovite phase transition. Using the size broadening of the diffraction peaks, the growth of nanocrystalline stishovite grains is resolved on the nanosecond timescale just after shock compression. At applied pressures above 18 GPa the nuclueationmore »of stishovite appears to be kinetically limited to 1.4±0.4 ns. The functional form of this grain growth suggests homogeneous nucleation and attachment as the growth mechanism. As a result, these are the first observations of crystalline grain growth in the shock front between low- and high-pressure states via XRD.« less

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

    SciTech Connect (OSTI)

    Hartwig, K. T.; Balachandran, S.; Mezyenski, R.; Seymour, N.; Robinson, J.; Barber, R. E.

    2014-01-27

    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.

  6. Laminar: Practical Fine-Grained Decentralized Information Flow Control

    E-Print Network [OSTI]

    Witchel, Emmett

    Laminar: Practical Fine-Grained Decentralized Information Flow Control Indrajit Roy Donald E-grained program data structures. This paper describes Laminar, the first system to implement de- centralized the labeled data in lexically scoped secu- rity regions. Laminar enforces the security policies specified

  7. ANNIVERSARY REVIEW Grain boundary energy anisotropy: a review

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    energy (B) gained when the two surfaces are brought together and new bonds are formed. The grain boundary with the stiffness of the material. The excess energy of the grANNIVERSARY REVIEW Grain boundary energy anisotropy: a review Gregory S. Rohrer Received: 29 April

  8. Profitable Grain Sorghum Production in the Rolling Plains. 

    E-Print Network [OSTI]

    Alexander, U.U.; Coffman, Cloyce G.; Boring, Emory P. III; McCoy, Norman; Weaver, Dave

    1987-01-01

    ? The Texa. A&M University System ? College Station, Texas PROFITABLE GRAIN SORGHUM PRODUCTION IN THE ROLLING PLAINS v.v. Alexander, Cloyce G. Coffman, Emory P. Boring III, Norman McCoy and Dave Weaver? Grain sorghum is grown on about 250,000 acres...

  9. The Imprint of Nova Nucleosynthesis in Presolar Grains

    E-Print Network [OSTI]

    Jordi Jose; Margarita Hernanz; Sachiko Amari; Katharina Lodders; Ernst Zinner

    2004-05-17

    Infrared and ultraviolet observations of nova light curves have confirmed grain formation in their expanding shells that are ejected into the interstellar medium by a thermonuclear runaway. In this paper, we present isotopic ratios of intermediate-mass elements up to silicon for the ejecta of CO and ONe novae, based on 20 hydrodynamic models of nova explosions. These theoretical estimates will help to properly identify nova grains in primitive meteorites. In addition, equilibrium condensation calculations are used to predict the types of grains that can be expected in the nova ejecta, providing some hints on the puzzling formation of C-rich dust in O>C environments. These results show that SiC grains can condense in ONe novae, in concert with an inferred (ONe) nova origin for several presolar SiC grains.

  10. Coarse-grained model of adsorption of blood plasma proteins onto nanoparticles

    E-Print Network [OSTI]

    Hender Lopez; Vladimir Lobaskin

    2015-08-06

    We present a coarse-grained model for evaluation of interactions of globular proteins with nanoparticles. The protein molecules are represented by one bead per aminoacid and the nanoparticle by a homogeneous sphere that interacts with the aminoacids via a central force that depends on the nanoparticle size. The proposed methodology is used to predict the adsorption energies for six common human blood plasma proteins on hydrophobic charged or neutral nanoparticles of different sizes as well as the preferred orientation of the molecules upon adsorption. Our approach allows one to rank the proteins by their binding affinity to the nanoparticle, which can be used for predicting the composition of the NP-protein corona. The predicted ranking is in good agreement with known experimental data for protein adsorption on surfaces.

  11. Low Latency Messages on Distributed Memory Multiprocessors

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

    Rosing, Matt; Saltz, Joel

    1995-01-01

    This article describes many of the issues in developing an efficient interface for communication on distributed memory machines. Although the hardware component of message latency is less than 1 ws on many distributed memory machines, the software latency associated with sending and receiving typed messages is on the order of 50 ?s. The reason for this imbalance is that the software interface does not match the hardware. By changing the interface to match the hardware more closely, applications with fine grained communication can be put on these machines. This article describes several tests performed and many of the issues involvedmore »in supporting low latency messages on distributed memory machines.« less

  12. Hardware Sizing for Software Application

    E-Print Network [OSTI]

    Swaminathan, Ganesh

    2009-05-15

    Hardware sizing is an approximation of the hardware resources required to support a software implementation. Just like any theoretical model, hardware sizing model is an approximation of the reality. Depending on the infrastructure needs, workload...

  13. Intra- and inter-grain currents in coated conductors with arbitrary grain boundary properties from magnetic measurements

    SciTech Connect (OSTI)

    Feenstra, Roeland [ORNL; Sinclair IV, John W [ORNL; Thompson, James R [ORNL; Christen, David K [ORNL

    2011-01-01

    A generalized methodology is described for determining both the intragranular and through-grain-boundary critical current densities in practical coated conductors from contact-free magnetic hysteresis measurements. The model incorporates the vector nature of current density J within the superconducting grains and current conservation with respect to the grain boundaries. Using physically observed values for the grain aspect ratio as input, the analysis yields the low-field intragranular critical current density J{sub c}{sup G} from a single field-dependent measurement of the global J{sub c} and provides a consistent description that spans the entire range from the weak-link (J{sub c}/J{sub c}{sup G}) to the single-grain (J{sub c}/J{sub c}{sup G} {yields} 1) limit. Results are given for ex situ processed RBCO coatings on RABiTS.

  14. Irradiation Assisted Grain Boundary Segregation in Steels

    SciTech Connect (OSTI)

    Lu, Zheng; Faulkner, Roy G.

    2008-07-01

    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)

  15. Deuterium enrichment of the interstellar grain mantle

    E-Print Network [OSTI]

    Das, Ankan; Chakrabarti, Sandip K

    2015-01-01

    We carry out Monte-Carlo simulation to study deuterium enrichment of interstellar grain mantles under various physical conditions. Based on the physical properties, various types of clouds are considered. We find that in diffuse cloud regions, very strong radiation fields persists and hardly a few layers of surface species are formed. In translucent cloud regions with a moderate radiation field, significant number of layers would be produced and surface coverage is mainly dominated by photo-dissociation products such as, C,CH_3,CH_2D,OH and OD. In the intermediate dense cloud regions (having number density of total hydrogen nuclei in all forms ~ 2 x 10^4 cm^-3), water and methanol along with their deuterated derivatives are efficiently formed. For much higher density regions (~ 10^6 cm^-3), water and methanol productions are suppressed but surface coverage of CO,CO_2,O_2,O_3 are dramatically increased. We find a very high degree of fractionation of water and methanol. Observational results support a high frac...

  16. Uranium vacancy mobility at the sigma 5 symmetric tilt grain boundary in UO2

    SciTech Connect (OSTI)

    Uberuaga, Blas P.

    2012-05-02

    An important consequence of the fissioning process occurring during burnup is the formation of fission products. These fission products alter the thermo-mechanical properties of the fuel. They also lead to macroscopic changes in the fuel structure, including the formation of bubbles that are connected to swelling of the fuel. Subsequent release of fission gases increase the pressure in the plenum and can cause changes in the properties of the fuel pin itself. It is thus imperative to understand how fission products, and fission gases in particular, behave within the fuel in order to predict the performance of the fuel under operating conditions. Fission gas redistribution within the fuel is governed by mass transport and the presence of sinks such as impurities, dislocations, and grain boundaries. Thus, to understand how the distribution of fission gases evolves in the fuel, we must understand the underlying transport mechanisms, tied to the concentrations and mobilities of defects within the material, and how these gases interact with microstructural features that might act as sinks. Both of these issues have been addressed in previous work under NEAMS. However, once a fission product has reached a sink, such as a grain boundary, its mobility may be different there than in the grain interior and predicting how, for example, bubbles nucleate within grain boundaries necessitates an understanding of how fission gases diffuse within boundaries. That is the goal of the present work. In this report, we describe atomic level simulations of uranium vacancy diffusion in the pressence of a {Sigma}5 symmetric tilt boundary in urania (UO{sub 2}). This boundary was chosen as it is the simplest of the boundaries we considered in previous work on segregation and serves as a starting point for understanding defect mobility at boundaries. We use a combination of molecular statics calculations and kinetic Monte Carlo (kMC) to determine how the mobility of uranium vacancies is altered at this particular grain boundary. Given that the diffusion of fission gases such as Xe are tied to the mobility of uranium vacancies, these results given insight into how fission gas mobility differs at grain boundaries compared to bulk urania.

  17. A coarse-grained model for PETN crystals

    SciTech Connect (OSTI)

    Gee, R; Wu, C; Maiti, A

    2006-02-10

    Using the energetic material Pentaerythritol Tetranitrate (PETN) as a specific example of molecular crystal, we describe the development of a simple coarse-graining procedure by grouping several atoms or whole functional groups into single charge-neutral beads. As compared to fully atomistic calculations the coarse-grained model speeds up simulations by more than two orders of magnitude. Yet, by adjusting only two parameters in the coarse-grained interaction, the model accurately predicts the lattice constants, sublimation energy, pressure-volume curve up to P=10 GPa, and energetically the most stable facets. Computed surface and desorption energies, bulk modulus, and equilibrium morphology are reported as well.

  18. Coarse-graining DNA for simulations of DNA nanotechnology

    E-Print Network [OSTI]

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

    2013-08-18

    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.

  19. Coarse-graining DNA for simulations of DNA nanotechnology

    E-Print Network [OSTI]

    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

    2013-01-01

    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.

  20. Suggestions for Controlling Insects in Farm-Stored Grain

    E-Print Network [OSTI]

    Hamman, Philip J.

    1982-01-01

    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 Figure 1. The map shows, by regions, the degree... to which farm-stored grain in the United States is subject to insect attack: Region 1, little if any damage occurs to grain on the farm during the first season's storage. Region 2, insects may be troublesome during the first season. Region 3, insects...

  1. Manufacturing process to reduce large grain growth in zirconium alloys

    DOE Patents [OSTI]

    Rosecrans, P.M.

    1984-08-01

    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.

  2. Strategic Petroleum Reserve: Analysis of size options

    SciTech Connect (OSTI)

    Not Available

    1990-02-01

    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.

  3. Distributed Generation

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

    Electricity, US Data. 6. Distributed Generation: Standby Generation and Cogeneration Ozz Energy Solutions, Inc. February 28 th , 2005. For more information about...

  4. Distributed generation

    SciTech Connect (OSTI)

    Ness, E.

    1999-09-02

    Distributed generation, locating electricity generators close to the point of consumption, provides some unique benefits to power companies and customers that are not available from centralized electricity generation. Photovoltaic (PV) technology is well suited to distributed applications and can, especially in concert with other distributed resources, provide a very close match to the customer demand for electricity, at a significantly lower cost than the alternatives. In addition to augmenting power from central-station generating plants, incorporating PV systems enables electric utilities to optimize the utilization of existing transmission and distribution.

  5. Wide size range fast integrated mobility spectrometer

    SciTech Connect (OSTI)

    Wang, Jian

    2013-10-29

    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.

  6. Coarse-Grain Recon gurable Computing Ethan A. Mirsky

    E-Print Network [OSTI]

    DeHon, André

    Coarse-Grain Recon gurable Computing by Ethan A. Mirsky Submitted to the Department of Electrical gurable Computing by Ethan A. Mirsky Submitted to the Department of Electrical Engineering and Computer

  7. Managing Insect and Mite Pests of Texas Small Grains 

    E-Print Network [OSTI]

    Patrick, Carl D.; Knutson, Allen E.

    2006-07-05

    Small grain crops are important for fall and winter livestock grazing. Pests such as small wireworms and cutworms cause significant damage to these crops. Complete information about sampling, economic thresholds, and control of these pests...

  8. Crystallographically consistent percolation theory for grain boundary networks

    E-Print Network [OSTI]

    Frary, Megan

    2005-01-01

    Grain boundaries are known to play a role in many important material properties including creep resistance, ductility and cracking resistance. Although the structure and properties of individual boundaries are important, ...

  9. Graph Coloring on a Coarse Grained Multiprocessor (extended abstract)

    E-Print Network [OSTI]

    Gebremedhin, Assefaw Hadish

    Graph Coloring on a Coarse Grained Multiprocessor (extended abstract) Assefaw Hadish Gebremedhin1 Allwright et al. (1995). However, in a recent result, Gebremedhin and Manne (1999a, 1999b) present

  10. Thermodynamics of microstructure evolution: grain growth Victor L. Berdichevsky

    E-Print Network [OSTI]

    Berdichevsky, Victor

    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

  11. Deadlock-free fine-grained thread migration

    E-Print Network [OSTI]

    Cho, Myong Hyon

    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, ...

  12. Small Grains Forage Management and Evaluation in Central Texas 

    E-Print Network [OSTI]

    Franks, Aaron Michael

    2013-04-25

    nutrition disorders in cattle. Milk fever (hypocalcemia) and grass tetany (hypomagnesemia) are common ailments of lactating cattle, but can also afflict young stocker steers that generally graze small grains, with tetany being most prevalent (Horn, et al...

  13. Grain boundary relaxation strengthening of nanocrystalline Ni–W alloys

    E-Print Network [OSTI]

    Rupert, Timothy J.

    The hardening effect caused by the relaxation of nonequilibrium grain boundary structure has been explored in nanocrystalline Ni–W alloys. First, the kinetics of relaxation hardening are studied, showing that higher annealing ...

  14. Phenological development of grain sorghum as affected by planting date 

    E-Print Network [OSTI]

    Medley, James C.

    1998-01-01

    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...

  15. 3/4/2014 These windmills are so tiny, you could fit 10 of them on a grain of rice | Grist http://grist.org/list/these-windmills-are-so-tiny-you-could-fit-10-of-them-on-a-grain-of-rice/ 1/2

    E-Print Network [OSTI]

    Chiao, Jung-Chih

    -Arlington The gospel about windmills is that bigger is better. And there are advantages to building bigger windmills-Arlington went the other way, and made micro windmills so small they're "a tenth the size of a grain of rice," Raw Story says. When a windmill is that tiny, wind comes easy -- you could just wave your hand over

  16. Systems simulation of oil additives to grain at terminal elevators 

    E-Print Network [OSTI]

    Goforth, Kerry James

    1985-01-01

    Negligible colorless, odorless stable, inert From: McIlveen, 1984 12 Previous Research Dust suppression characteristics of mineral oil have been evaluated at the United States Grain Marketing Research Laboratory in Manhatten, Kansas. Lai et al. (1981... and are not separated out by normal grain inspection procedures. Foreign matter reductions of up to 1. 5 percent have been reported in informal experiments (Hegadorn, 1984). Country elevators that have no dust collection systems are realizing savings from oil...

  17. Grained composite materials prepared by combustion synthesis under mechanical pressure

    DOE Patents [OSTI]

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

    1990-01-01

    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.

  18. Enhanced Electrochemical Lithium Storage Activity of LiCrO2 by Size Effect

    SciTech Connect (OSTI)

    Feng, G.; Li, L; Liu, J; Liu, N; Li, H; Yang, X; Huang, X; Chen, L; Nam, K; Yoon, W

    2009-01-01

    Cr8O21 was chemically lithiated using a lithium-biphenyl-dimethoxyethane solution. Lithiated Cr8O21 shows a structure in which as-formed LiCrO2 units are sandwiched between Cr2O3 superlattice layers. Chemically lithiated Cr8O21 shows a delithiation capacity of 200 mAh g-1. It means that LiCrO2 units in lithiated Cr8O21 are electrochemically active. This finding is opposite to previous reports that LiCrO2 materials have very poor Li-storage capacities. Our new result implies that LiCrO2 with extremely small domain size could show enhanced reactivity. This proposal is proved unambiguously by the fact that LiCrO2 powder materials with smaller grain size (<20 nm) show much higher capacities than LiCrO2 materials with larger grain size (>50 nm). In addition, it is found that the cation mixing is more significantly in LiCrO2 materials with smaller grain size, which seems a key factor for the storage and transport of lithium in layered Cr-based materials. The cation mixing may also explain the result that the lattice parameters of LiCrO2 do not change significantly upon lithium extraction and insertion, investigated by in situ and ex situ XRD techniques.

  19. Measurements of grain boundary properties in nanocrystalline ceramics

    SciTech Connect (OSTI)

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

    1990-11-01

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

  20. Grain-by-grain study of the mechanisms of crack propagation during iodine stress corrosion cracking of Zircaloy-4

    SciTech Connect (OSTI)

    Haddad, R.E. [CNEA, Buenos Aires (Argentina); Dorado, A.O. [CONICET, Buenos Aires (Argentina)

    1994-12-31

    This paper describes the tests conducted to determine the conditions leading to cracking of a specified grain of metal, during the iodine stress corrosion cracking (SCC) of zirconium alloys, focusing on the crystallographic orientation of crack paths, the critical stress conditions, and the significance of the fractographic features encountered. In order to perform crystalline orientation of fracture surfaces, a specially heat-treated Zircaloy-4 having very large grains, grown up to the wall thickness, was used. Careful orientation work has proved that intracrystalline pseudo-cleavage occurs only along basal planes. the effects of anisotropy, plasticity, triaxiality, and residual stresses originated in thermal contraction have to be considered to account for the influence of the stress state. A grain-by-grain calculation led to the conclusion that transgranular cracking always takes place on those bearing the maximum resolved tensile stress perpendicular to basal planes. Propagation along twin boundaries has been identified among the different fracture modes encountered.

  1. Tolerance of combined salinity and O2 deficiency in Hordeum marinum accessions from the grain-belt of Western Australia

    E-Print Network [OSTI]

    Malik1,2,3, AI; English1,2, JP; Shepherd1,4, KA; Islam2,5, AKMR; Colmer1,2, TD

    2009-01-01

    accessions from the grain-belt of Western Australia forcollected from the grain-belt of Western Australia. Single

  2. The Effect of High Temperature Annealing on the Grain Characteristics of a Thin Chemical Vapor Deposition Silicon Carbide Layer.

    SciTech Connect (OSTI)

    Isabella J van Rooyen; Philippus M van Rooyen; Mary Lou Dunzik-Gougar

    2013-08-01

    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 1000-1250°C, the temperature may reach 1600°C 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].

  3. Experimental and numerical investigation of phonon mean free path distribution

    E-Print Network [OSTI]

    Zeng, Lingping

    2013-01-01

    Knowledge of phonon mean free path (MFP) distribution is critically important to engineering size effects. Phenomenological models of phonon relaxation times can give us some sense about the mean free path distribution, ...

  4. Normal Distribution

    E-Print Network [OSTI]

    User

    NORMAL DlSTRlBUTION TABLE. Entries represent the area under the standardized normal distribution from -w to z, Pr(Z

  5. Decoding the message from meteoritic stardust silicon carbide grains

    SciTech Connect (OSTI)

    Lewis, Karen M.; Lugaro, Maria; Gibson, Brad K.; Pilkington, Kate

    2014-05-02

    SiC mainstream grains are presolar grains believed to form in the envelopes of carbon rich asymptotic giant branch (AGB) stars with masses between 1.5 and 3 solar masses. These grains represent a conundrum as the {sup 29}Si and {sup 30}Si abundances indicate that they formed in stars of super-solar metallicity, before the solar system formed. To shed light on this problem, we use silicon isotopic abundances to derive an age-metallicity relation for the stars believed to have produced the SiC mainstream grains. For 2732 mainstream SiC grains listed in the Presolar Grain Database, we use the {sup 29}Si abundances with the latest galactic chemical evolution (GCE) models to derive [Fe/H], and {sup 30}Si abundances along with the models of Zinner et al. (2006) to determine an approximate birth age for the parent AGB star. Comparing our age-metallicity relation with observational relationships derived for nearby stars, we find that the spread of [Fe/H] is in agreement, but the mean [Fe/H] in our relation is higher by 0.2 dex. We propose that this difference is because stars with higher [Fe/H] produce more dust and thus are over-represented in our age metallicity diagram, a finding consistent with previous published works. 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 a function of the metallicity.

  6. Grain Fish Money Financing Africa's Green and Blue Revolutions Financing Africa's Green and Blue Revolutions

    E-Print Network [OSTI]

    Grain Fish Money Financing Africa's Green and Blue Revolutions 1 Financing Africa's Green and Blue Revolutions GRAIN FISH MONEY AFRICA PROGRESS REPORT 2014 #12;AFRICA PROGRESS REPORT 2014 2 #12;Grain Fish Money Financing Africa's Green and Blue Revolutions 3 #12;#12;Grain Fish Money Financing Africa's Green

  7. Mapping Biomass Distribution Potential

    E-Print Network [OSTI]

    Schaetzel, Michael

    2010-11-18

    stream_size 1487 stream_content_type text/plain stream_name ku_gis_day_2010_schaetzel.pdf.txt stream_source_info ku_gis_day_2010_schaetzel.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 Mapping Biomass... Distribution Potential Michael Schaetzel Undergraduate ? Environmental Studies ? University of Kansas L O C A T S I O N BIOMASS ENERGY POTENTIAL o According to DOE, Biomass has the potential to provide 14% of the nation’s power o Currently 1% of...

  8. Equilibrium distribution

    E-Print Network [OSTI]

    Ashot Vagharshakyan

    2015-08-29

    In the paper discusses the interaction between two charged balls in equilibrium state. It is shown that, depending of the sizes, charges and distance, the balls can move in the same or opposite direction. They can repulse and attract. It is proved, that one of the balls may vibrate.

  9. Does semantic size affect size constancy scaling using lexical stimuli? 

    E-Print Network [OSTI]

    Beveridge, Madeleine

    2010-11-24

    Binocular disparity allows us to perceive the world in 3-dimensions through the process of stereopsis. In this study, we used binocular disparity to induce the size constancy illusion in lexical stimuli. 47 undergraduate ...

  10. Solvent Entropy in and Coarse-Graining of Polymer Lattice Models

    E-Print Network [OSTI]

    Pengfei Zhang; Qiang Wang

    2012-11-21

    The self- and mutual-avoiding walk used in conventional lattice models for polymeric systems requires that all lattice sites, polymer segments, and solvent molecules (unoccupied lattice sites) have the same volume. This incorrectly accounts for the solvent entropy (i.e., size ratio between polymer segments and solvent molecules), and also limits the coarse-graining capability of such models, where the invariant degree of polymerization controlling the system fluctuations is too small (thus exaggerating the system fluctuations) compared to that in most experiments. Here we show how to properly account for the solvent entropy in the recently proposed lattice models with multiple occupancy of lattice sites [Q. Wang, Soft Matter 5, 4564 (2009)], and present a quantitative coarse-graining strategy that ensures both the solvent entropy and the fluctuations in the original systems are properly accounted for using such lattice models. Although proposed based on homogeneous polymer solutions, our strategy is equally applicable to inhomogeneous systems such as polymer brushes immersed in a small-molecule solvent.

  11. How Focal Adhesion Size Depends on Integrin Affinity Tong Zhao,,

    E-Print Network [OSTI]

    Dinner, Aaron

    How Focal Adhesion Size Depends on Integrin Affinity Tong Zhao,, Ying Li,, and Aaron R. Dinner the thermodynamics and kinetics of integrin receptor binding and clustering impact the formation of focal adhesions in their environment. Cells on chemically well-defined surfaces were observed to have distributions of focal adhesions

  12. Silicate Emission Profiles from Low-Mass Protostellar Disks in the Orion Nebula: Evidence for Growth and Thermal Processing of Grains

    E-Print Network [OSTI]

    R. Y. Shuping; Marc Kassis; Mark Morris; Nathan Smith; John Bally

    2006-05-05

    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.

  13. Avalanche: A Fine-Grained Flow Graph Model for Irregular Applications on Distributed-Memory Systems

    E-Print Network [OSTI]

    Newton, Ryan R.

    libraries [18, 30]. To address this need we propose a new C++ library, Avalanche, for expressing fine computations. However, most of these models either require specialized languages and compilers or are library generates active-message handlers. Avalanche is built as a C++ library on top of our previously

  14. Children's Clothes - Size and Selection. 

    E-Print Network [OSTI]

    Vanderpoorten, Ann; Kerbel, Claudia

    1980-01-01

    , children's clothing should fit well, allow for growth and be durable and easy to care for. Children's Sizes The age of a child does not determine size. Chil dren of the same age may vary greatly in height, weight and body measurements. Clothing... and pants provide room for growth. Durability Because growing children are active and vigorous in play, select clothing that will withstand stress and strain. Clothing that wears out or falls apart before the child outgrows it is frustrating as well...

  15. Nebraska's Cattle Feeding Industry: Size, Structure and Related Industries

    E-Print Network [OSTI]

    Farritor, Shane

    growing production of distillers grains and other feed byproducts from bio-energy produc- tion plants

  16. Quasi-isentropic and shock compression of FCC and BCC metals : effects of grain size and stacking-fault energy

    E-Print Network [OSTI]

    Jarmakani, Hussam N.

    2008-01-01

    range including both the thermal activation regime and theyield stress in the thermal activation regime are given by:transition between the thermal activation regime and the

  17. Quasi-isentropic and shock compression of FCC and BCC metals : effects of grain size and stacking-fault energy

    E-Print Network [OSTI]

    Jarmakani, Hussam N.

    2008-01-01

    A recovery tube filled with aerogel usually captures theand collected in both aerogel and on glass. RepresentativeGlass Shield Glass Shield Aerogel Aerogel Aerogel Aerogel

  18. Effect of Y-211 particle size on the growth of single grain Y–Ba–Cu–O bulk superconductors

    E-Print Network [OSTI]

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

    2014-12-01

    , bulk HTS have consi- derable potential for use in a wide variety of applications, including magnetic bearings, flywheel energy storage systems and rotating ele- ctrical machines [2]. Practical Y–Ba–Cu–O (YBCO) bulk superconductors consist of a YBa2Cu3O...

  19. Effect of WC/TiC grain size ratio on microstructure and mechanical properties of WCTiCCo cemented carbides

    E-Print Network [OSTI]

    Hong, Soon Hyung

    of TiC powder as 1 lm. The microstructures of sintered WC­TiC­10 wt%Co cemented carbides were than that expected by modified Hall­Petch type equation. Transverse rupture strength of WC­20TiC­10 wt for decades [1]. Generally, cemented carbides are based on the WC­Co and some cubic carbide such as TiC, Ta

  20. Optimization of grain number, size and yield as affected by plant spacing and genotype in Sorghum bicolor (L.) Moench 

    E-Print Network [OSTI]

    Traore, Lamine

    1982-01-01

    , 000, 146, 000, 190, 000, and 257, 000 plants/ha (ppha) . Hybrids were ATx378xRTx430, ATx623x77CS3, and ATx625x77CS1. There were significant differences in yield due to plant population at the two locations used for this study (College Station... and Lubbock, TX. ) . All hybrids produced highest yields at 32, 000 ppha population at Lubbock. At College Station the hybrid ATx378xRTx430 showed an increase in yield as plant population increased but ATx623 x77CS3 and ATx625x77CS1 did not show the same...

  1. Role of Crystallographic Texture and Grain Size on Low Temperature Deformation and Formability of a Mg Alloy 

    E-Print Network [OSTI]

    Dogan, Ebubekir

    2014-12-12

    Figure 2.1 Schematics of the three ECAP cases studied in the present work with (0002) pole figures showing different AZ31 Mg alloy texture, Texture1: hot-rolled texture, basal poles are parallel to ED, Texture2...: hot-rolled texture but basal poles are parallel to FD, Texture3: typical conventional area reduction extrusion texture; basal poles are aligned around the center rim. ED: Extrusion direction, LD: Longitudinal...

  2. Coarse-grained electrostatic interactions of coronene: Towards the crystalline phase

    E-Print Network [OSTI]

    Thomas Heinemann; Karol Palczynski; Joachim Dzubiella; Sabine H. L. Klapp

    2015-06-05

    In this article we present and compare two different, coarse-grained approaches to model electrostatic interactions of anisotropic organic molecules, specifically coronene. Our study is an extension of previous work [J. Chem. Phys. 141, 214110 (2014)] where we proposed, based on a systematic coarse-graining procedure starting from the atomistic level, an anisotropic effective (Gay-Berne-like) potential capable of describing van-der-Waals contributions to the interaction energy. To take into account electrostatics, we introduce, first, a linear quadrupole moment along the symmetry axis of the coronene disk. The second approach takes into account the fact that the partial charges within the molecules are distributed in a ring-like fashion. We then reparametrize the effective Gay-Berne-like potential such that it matches, at short distances, the ring-ring potential. To investigate the validity of these two approaches, we perform many-particle Molecular Dynamics (MD) simulations, focusing on the crystalline phase (karpatite) where electrostatic interaction effects are expected to be particularly relevant. Specifically, we investigate various structural parameters as well as the melting transition. We find that the second approach yields consistent results with those from experiments despite the fact that the underlying potential decays with the wrong distance dependence at large molecule separations. Our strategy can be transferred to a broader class of molecules, such as benzene or hexabenzocoronene.

  3. Fine-Grained Multi-Resource Scheduling in Cloud Datacenters

    E-Print Network [OSTI]

    Fu, Xiaoming

    Fine-Grained Multi-Resource Scheduling in Cloud Datacenters Yuan Zhang University of G--Cloud datacenters typically require tenants to spec- ify the resource demands for the virtual machines (VMs. Unfortunately, this leads to low resource utilization of cloud datacenters as tenants are obligated

  4. Architecture Enhancements for the ADRES Coarse-Grained Reconfigurable Array

    E-Print Network [OSTI]

    architectures provide power efficiency, flexibility and high performance for next generation embedded multimediaArchitecture Enhancements for the ADRES Coarse-Grained Reconfigurable Array Frank Bouwens1 Leuven, Belgium {bouwens,berekovic,desutter}@imec.be 2 Delft University of Technology, Computer

  5. FEA Simulations of Magnets with Grain Oriented Steel

    SciTech Connect (OSTI)

    Witte H.

    2012-08-06

    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.

  6. Magnetic Fields via Polarimetry: Progress of Grain Alignment Theory

    E-Print Network [OSTI]

    A. Lazarian

    2002-08-28

    Most astrophysical systems, e.g. stellar winds, the diffuse interstellar medium, molecular clouds, are magnetized with magnetic fields that influence almost all of their properties. One of the most informative techniques of magnetic field studies is based on the use of starlight polarization and polarized emission arising from aligned dust. How reliable the interpretation of the polarization maps in terms of magnetic fields is the issue that the grain alignment theory addresses. Although grain alignment is a problem of half a century standing, recent progress achieved in the field makes us believe that we are approaching the solution of this mystery. I review basic physical processes involved in grain alignment and discuss the niches for different alignment mechanisms. I show why mechanisms that were favored for decades do not look so promising right now, while the radiative torque mechanism ignored for more than 20 years looks so attractive. I define the observational tests and outline the circumstances when grain alignment theory predicts that new yet untapped information of magnetic field structure is available through polarimetry. In particular, I touch upon mapping magnetic fields in circumstellar regions, interplanetary space and in comet comae.

  7. Grain Sorghum By-Product Feeds for Farm Animals. 

    E-Print Network [OSTI]

    1951-01-01

    . GRAIN SORGHUM BY-PRODUCT FEEDS FOR FARM ANIMALS 15 SORGHUJI GLUTEN FEED Sorghum gluten feed was used in three different combi- nations in experimental rations for fattening steers. In the first ration, it was fed as the only concentrate received... .................................................................................................. 18 Sorghum gluten meal .................................................................................. 18 experimental ration ............................................................................. 18...

  8. Thermodynamics of Protein Folding from Coarse-Grained Models' Perspectives

    E-Print Network [OSTI]

    Janke, Wolfhard

    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

  9. Microwave sintering of sol-gel derived abrasive grain

    DOE Patents [OSTI]

    Plovnick, Ross (St. Louis Park, MN); Celikkaya, Ahmet (Woodbury, MN); Blake, Rodger D. (Tuscon, AZ)

    1997-01-01

    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.

  10. Fine-Grained Power Management Using Process-level Profiling

    E-Print Network [OSTI]

    Shi, Weisong

    . To evaluate energy efficiency, the Green Grid group proposed the definition of power usage effectiveness (PUE1 Fine-Grained Power Management Using Process-level Profiling Hui Chen, Youhuizi Li and Weisong Shi Department of Computer Science Wayne State University {huichen,huizi,weisong}@wayne.edu Abstract--Low-power

  11. Modeling Segregation and Grain Structure Development in Equiaxed

    E-Print Network [OSTI]

    Beckermann, Christoph

    grain and at the scale of a casting. The need for much additional researchis emphasized. INTRODUCTION The as-solidified structure of most statically and continuously cast metal alloys features both columnar, improved feed- ing to compensate for shrinkage and less hot cracking, improved surface proper- ties

  12. Geometric and topological properties of the canonical grain growth microstructure

    E-Print Network [OSTI]

    Jeremy K. Mason; Emanuel A. Lazar; Robert D. MacPherson; David J. Srolovitz

    2015-07-13

    Many physical systems can be modeled as large sets of domains "glued" together along boundaries - biological cells meet along cell membranes, soap bubbles meet along thin films, countries meet along geopolitical boundaries, and metallic crystals meet along grain interfaces. Each class of microstructures results from a complex interplay of initial conditions and particular evolutionary dynamics. The statistical steady-state microstructure resulting from isotropic grain growth of a polycrystalline material is canonical in that it is the simplest example of a cellular microstructure resulting from a gradient flow of a simple energy, directly proportional to the total length or area of all cell boundaries. As many properties of polycrystalline materials depend on their underlying microstructure, a more complete understanding of the grain growth steady-state can provide insight into the physics of a broad range of everyday materials. In this paper we report geometric and topological features of these canonical two- and three-dimensional steady-state microstructures obtained through large, accurate simulations of isotropic grain growth.

  13. Manufacturing process to reduce large grain growth in zirconium alloys

    DOE Patents [OSTI]

    Rosecrans, Peter M. (Niskayuna, NY)

    1987-01-01

    A method of treating cold-worked zirconium alloys to reduce large grain gth during thermal treatment at temperatures above the recrystallization temperature of the alloy comprising heating the cold-worked alloy between about 1300.degree.-1350.degree. F. for 1 to 3 hours prior to treatment above its recrystallization temperature.

  14. Empirical distribution Theoretical2distribution

    E-Print Network [OSTI]

    Reich, David

    2 distribution. #12;Supplementary Table 1: Simulations using K axes of variation K = 1 K = 2 K = 5 K SNPs 0.4923 0.4916 0.4891 0.4860 Proportion of associations reported as significant by EIGENSTRAT adjusting along the top K axes of variation, for various values of K. #12;Page 2 Supplementary Table 2

  15. Chapter 6 Continuous Distribution: The Normal Distribution

    E-Print Network [OSTI]

    Hong, Don

    Chapter 6 Continuous Distribution: The Normal Distribution 6.1 Introduction 6.2 Properties of a Normal Distribution 6.3 The Standard Normal Distribution 6.4 Applications of Normal Distribution 6.5 The Central Limit Theorem 6.6 The Normal Approximation to the Binomial Distribution Definition. A continuous

  16. probability distributions

    E-Print Network [OSTI]

    Heller, Barbara

    probabilities in the standard normal table What is the area to the left of Z=1.51 in a standard normal curve? Z=1.51 Z=1.51 Area is 93.45% #12;Exercises · If scores are normally distributed with a mean of 30 beauty of the normal curve: No matter what and are, the area between - and + is about 68%; the area

  17. Computer simulation study of the structure of vacancies in grain boundaries

    SciTech Connect (OSTI)

    Brokman, A.; Bristowe, P.D.; Balluffi, R.W.

    1981-01-01

    The structure of vacancies in grain boundaries has been investigated by computer molecular statics employing pairwise potentials. In order to gain an impression of the vacancy structures which may occur generally, a number of variables was investigated including: metal type, boundary type, degree of lattice coincidence and choice of boundary site. In all cases the vacancies remained as distinguishable point defects in the relatively irregular boundary structures. However, it was found that the vacancy often induced relatively large atomic displacements in the core of the boundary. These displacements often occurred only in the direct vicinity of the vacancy, but in certain cases they were widely distributed in the boundary, sometimes at surprisingly large distances.

  18. ARM - Measurement - Cloud droplet 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Comments?govInstrumentsnoaacrnBarrow, Alaska Outreach Home Roomparticle size distributionconcentrationdroplet size

  19. Concentration of measures via size biased couplings

    E-Print Network [OSTI]

    Ghosh, Subhankar

    2009-01-01

    Let $Y$ be a nonnegative random variable with mean $\\mu$ and finite positive variance $\\sigma^2$, and let $Y^s$, defined on the same space as $Y$, have the $Y$ size biased distribution, that is, the distribution characterized by E[Yf(Y)]=\\mu E f(Y^s) for all functions $f$ for which these expectations exist. Under a variety of conditions on the coupling of Y and $Y^s$, including combinations of boundedness and monotonicity, concentration of measure inequalities hold. Examples include the number of relatively ordered subsequences of a random permutation, sliding window statistics including the number of m-runs in a sequence of coin tosses, the number of local maximum of a random function on a lattice, the number of urns containing exactly one ball in an urn allocation model, the volume covered by the union of $n$ balls placed uniformly over a volume n subset of d diml Euclidean space, the number of bulbs switched on at the terminal time in the so called lightbulb process, the number of isolated vertices in the ...

  20. Metal oxide porous ceramic membranes with small pore sizes

    DOE Patents [OSTI]

    Anderson, Marc A. (Madison, WI); Xu, Qunyin (Madison, WI)

    1991-01-01

    A method is disclosed for the production of metal oxide ceramic membranes of very small pore size. The process is particularly useful in the creation of titanium and other transition metal oxide membranes. The method utilizes a sol-gel process in which the rate of particle formation is controlled by substituting a relatively large alcohol in the metal alkoxide and by limiting the available water. Stable, transparent metal oxide ceramic membranes are created having a narrow distribution of pore size, with the pore diameter being manipulable in the range of 5 to 40 Angstroms.

  1. Ion beam-induced amorphous-to-tetragonal phase transformation and grain growth of nanocrystalline zirconia

    SciTech Connect (OSTI)

    Lian, Jie; Zhang, Jiaming; Namavar, Fereydoon; Zhang, Yanwen; Lu, Fengyuan; Haider, Hani; Garvin, Kevin; Weber, William J.; Ewing, Rodney C.

    2009-05-26

    Nanocrystalline zirconia has recently attracted extensive research interest due to its unique mechanical, thermal and electrical properties as compared to bulk zirconia counterparts, and it is of particular importance to control the phase stability of different polymorphs (amorphous, cubic, tetragonal and monoclinic phases) at different size regimes. In this paper, we performed ion beam bombardments on bilayers (amorphous and cubic) of pure nano-zirconia using 1 MeV Kr2+ irradiation. Transmission electron microscopy (TEM) analysis reveals that amorphous zirconia transforms to a tetragonal structure under irradiation at room temperature, suggesting that the tetragonal phase is more energetically favorable under these conditions. The final grain size of the tetragonal zirconia can be controlled by irradiation conditions. The irradiation-induced nanograins of tetragonal ZrO2 are stable at ambient conditions and maintain their physical integrity over a long period of time after irradiation. These results demonstrated that ion-beam modification methods provide the means to control the phase stability and structure of zirconia polymorphs.

  2. Ellipsometry characterization of polycrystalline ZnO layers with the modeling of carrier concentration gradient: Effects of grain boundary, humidity, and surface texture

    SciTech Connect (OSTI)

    Sago, Keisuke; Fujiwara, Hiroyuki; Kuramochi, Hideto; Iigusa, Hitoshi; Utsumi, Kentaro

    2014-04-07

    Spectroscopic ellipsometry (SE) has been applied to study the effects of grain boundary, humidity, and surface texture on the carrier transport properties of Al-doped ZnO layers fabricated by dc and rf magnetron sputtering. In the SE analysis, the variation in the free carrier absorption toward the growth direction, induced by the ZnO grain growth on foreign substrates, has been modeled explicitly by adopting a multilayer model in which the optical carrier concentration (N{sub opt}) varies continuously with a constant optical mobility (?{sub opt}). The effect of the grain boundary has been studied by comparing ?{sub opt} with Hall mobility (?{sub Hall}). The change in ?{sub Hall}/?{sub opt} indicates a sharp structural transition of the ZnO polycrystalline layer at a thickness of d???500?nm, which correlates very well with the structure confirmed by transmission electron microscopy. In particular, below the transition thickness, the formation of the high density grain boundary leads to the reduction in the ?{sub Hall}/?{sub opt} ratio as well as N{sub opt}. As a result, we find that the thickness dependence of the carrier transport properties is almost completely governed by the grain boundary formation. On the other hand, when the ZnO layer is exposed to wet air at 85?°C, ?{sub Hall} reduces drastically with a minor variation of ?{sub opt} due to the enhanced grain boundary scattering. We have also characterized textured ZnO:Al layers prepared by HCl wet etching by SE. The analysis revealed that the near-surface carrier concentration increases slightly after the etching. We demonstrate that the SE technique can be applied to distinguish various rough textured structures (size???1??m) of the ZnO layers prepared by the HCl etching.

  3. Characterization of Large Grain Nb Ingot Microstructure Using OIM and Laue Methods

    SciTech Connect (OSTI)

    D. Kang, D.C. Baars, T.R. Bieler, G. Ciovati, C. Compton, T.L. Grimm, A.A. Kolka

    2011-07-01

    Large grain niobium is being examined for fabricating superconducting radiofrequency cavities as an alternative to using rolled sheet with fine grains. It is desirable to know the grain orientations of a niobium ingot slice before fabrication, as this allows heterogeneous strain and surface roughness effects arising from etching to be anticipated. Characterization of grain orientations has been done using orientation imaging microscopy (OIM), which requires destructive extraction of pieces from an ingot slice. Use of a Laue camera allows nondestructive characterization of grain orientations, a process useful for evaluating slices and deformation during the manufacturing process. Five ingot slices from CBMM, Ningxia, and Heraeus are compared. One set of slices was deformed into a half cell and the deformation processes that cause crystal rotations have been investigated and compared with analytical predictions. The five ingot slices are compared in terms of their grain orientations and grain boundary misorientations, indicating no obvious commonalities, which suggests that grain orientations develop randomly during solidification.

  4. An evaluation of grain boundary engineering technology and processing scale-up

    E-Print Network [OSTI]

    Zelinski, Jeffrey A

    2005-01-01

    Grain boundary engineering is the manipulation of low stacking-fault energy, face- centered cubic material microstructures to break the connectivity of the general grain boundary network through the addition of special ...

  5. Grain refinement and texture development of cast bi90sb10 alloy via severe plastic deformation 

    E-Print Network [OSTI]

    Im, Jae-taek

    2009-05-15

    The purpose of this work was to study learn about grain refinement mechanisms and texture development in cast n-type Bi90Sb10 alloy caused by severe plastic deformation. The practical objective is to produce a fine grained ...

  6. Modeling Elasto-Plastic Behavior of Polycrystalline Grain Structure of Steels at Mesoscopic Level

    E-Print Network [OSTI]

    Cizelj, Leon

    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

  7. Mechanical Properties and Radiation Tolerance of Ultrafine Grained and Nanocrystalline Metals 

    E-Print Network [OSTI]

    Sun, Cheng

    2013-04-26

    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...

  8. Influence of grain boundary energy on the nucleation of complexion transitions

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    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

  9. Size exclusion deep bed filtration: Experimental and modelling uncertainties

    SciTech Connect (OSTI)

    Badalyan, Alexander You, Zhenjiang; Aji, Kaiser; Bedrikovetsky, Pavel; Carageorgos, Themis; Zeinijahromi, Abbas

    2014-01-15

    A detailed uncertainty analysis associated with carboxyl-modified latex particle capture in glass bead-formed porous media enabled verification of the two theoretical stochastic models for prediction of particle retention due to size exclusion. At the beginning of this analysis it is established that size exclusion is a dominant particle capture mechanism in the present study: calculated significant repulsive Derjaguin-Landau-Verwey-Overbeek potential between latex particles and glass beads is an indication of their mutual repulsion, thus, fulfilling the necessary condition for size exclusion. Applying linear uncertainty propagation method in the form of truncated Taylor's series expansion, combined standard uncertainties (CSUs) in normalised suspended particle concentrations are calculated using CSUs in experimentally determined parameters such as: an inlet volumetric flowrate of suspension, particle number in suspensions, particle concentrations in inlet and outlet streams, particle and pore throat size distributions. Weathering of glass beads in high alkaline solutions does not appreciably change particle size distribution, and, therefore, is not considered as an additional contributor to the weighted mean particle radius and corresponded weighted mean standard deviation. Weighted mean particle radius and LogNormal mean pore throat radius are characterised by the highest CSUs among all experimental parameters translating to high CSU in the jamming ratio factor (dimensionless particle size). Normalised suspended particle concentrations calculated via two theoretical models are characterised by higher CSUs than those for experimental data. The model accounting the fraction of inaccessible flow as a function of latex particle radius excellently predicts normalised suspended particle concentrations for the whole range of jamming ratios. The presented uncertainty analysis can be also used for comparison of intra- and inter-laboratory particle size exclusion data.

  10. A stochastic model and Monte Carlo algorithm for fluctuation-induced H$_2$ formation on the surface of interstellar dust grains

    E-Print Network [OSTI]

    Sabelfeld, Karl

    2015-01-01

    A stochastic algorithm for simulation of fluctuation-induced kinetics of H$_2$ formation on grain surfaces is suggested as a generalization of the technique developed in our recent studies where this method was developed to describe the annihilation of spatially separate electrons and holes in a disordered semiconductor. The stochastic model is based on the spatially inhomogeneous, nonlinear integro-differential Smoluchowski equations with random source term. In this paper we derive the general system of Smoluchowski type equations for the formation of H$_2$ from two hydrogen atoms on the surface of interstellar dust grains with physisorption and chemisorption sites. We focus in this study on the spatial distribution, and numerically investigate the segregation in the case of a source with a continuous generation in time and randomly distributed in space. The stochastic particle method presented is based on a probabilistic interpretation of the underlying process as a stochastic Markov process of interacting ...

  11. Grain boundary characterization in an X750 alloy

    SciTech Connect (OSTI)

    Kevin Fisher; Sebastien Teysseyre; Emmanuelle Marquis

    2012-11-01

    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.

  12. Coarse-grained description of a passive scalar

    E-Print Network [OSTI]

    Antonio Celani; Marco Martins Afonso; Andrea Mazzino

    2006-02-27

    The issue of the parameterization of small-scale dynamics is addressed in the context of passive-scalar turbulence. The basic idea of our strategy is to identify dynamical equations for the coarse-grained scalar dynamics starting from closed equations for two-point statistical indicators. With the aim of performing a fully-analytical study, the Kraichnan advection model is considered. The white-in-time character of the latter model indeed leads to closed equations for the equal-time scalar correlation functions. The classical closure problem however still arises if a standard filtering procedure is applied to those equations in the spirit of the large-eddy-simulation strategy. We show both how to perform exact closures and how to identify the corresponding coarse-grained scalar evolution.

  13. Experimental evidence of water formation on interstellar dust grains

    E-Print Network [OSTI]

    Dulieu, F; Fillion, J-H; Matar, E; Momeni, A; Pirronello, V; Lemaire, J L

    2009-01-01

    The synthesis of water is one necessary step in the origin and development of life. It is believed that pristine water is formed and grows on the surface of icy dust grains in dark interstellar clouds. Until now, there has been no experimental evidence whether this scenario is feasible or not. We present here the first experimental evidence of water synthesis under interstellar conditions. After D and O deposition on a water ice substrate (HO) held at 10 K, we observe production of HDO and DO. The water substrate itself has an active role in water formation, which appears to be more complicated than previously thought. Amorphous water ice layers are the matrices where complex organic prebiotic species may be synthesized. This experiment opens up the field of a little explored complex chemistry that could occur on interstellar dust grains, believed to be the site of key processes leading to the molecular diversity and complexity observed in our universe.

  14. Published as Europhys. Lett. 110:36001, (2015) Direct observation of size scaling and elastic

    E-Print Network [OSTI]

    Nordlund, Kai

    2015-01-01

    provide direct evidence for a power-law size distribution of nano-scale defects formed in high-energy cascades, with an upper size limit independent of the incident ion energy, as predicted by Sand et al. [Eur and high thermal conductivity [?, ?], is expected to be significantly affected by neu- trons produced from

  15. Optimization of cement and fly ash particle sizes to produce sustainable concretes Dale P. Bentz a,

    E-Print Network [OSTI]

    Bentz, Dale P.

    Optimization of cement and fly ash particle sizes to produce sustainable concretes Dale P. Bentz a of experiment Fly ash Hydration Particle size distribution Strength Sustainability a b s t r a c t In the drive. High volume fly ash concretes have been proposed as one potential approach for achieving substantial

  16. Broad-scale patterns of body size in squamate reptiles of Europe and

    E-Print Network [OSTI]

    Rodríguez, Miguel Ángel

    ORIGINAL ARTICLE Broad-scale patterns of body size in squamate reptiles of Europe and North America and western Europe. Methods We processed distribution maps for native species of squamate reptiles to document by the data. Results Europe is characterized by clear latitudinal trends in body size, whereas geographical

  17. IEEE ELECTRON DEVICE LETTERS, VOL. 20, NO. 2, FEBRUARY 1999 97 Effects of Longitudinal Grain Boundaries

    E-Print Network [OSTI]

    IEEE ELECTRON DEVICE LETTERS, VOL. 20, NO. 2, FEBRUARY 1999 97 Effects of Longitudinal Grain grains in a direction longitudinal to that of the current flow, whereas in SPC-TFT's, the grain by a competitive earmarked research grant from the Research Grants Council of Hong Kong and a grant from the Hong

  18. Numerical analysis of a 3D radially symmetric grain attached to a free crystal surface

    E-Print Network [OSTI]

    Novick-Cohen, Amy

    boundary motion, the groove depth varies non-monotonely in time, and after annihilation of the grain on the kinetics of grain boundary migration for typical values of the parameters, but that it may even accelerate migration in very special cases. In none of the theoretical papers that considered coupled grain boundary

  19. Copyright (to be inserted by the publisher ) Mesoscale simulation of grain growth

    E-Print Network [OSTI]

    Citation & Copyright (to be inserted by the publisher ) Mesoscale simulation of grain growth David, USA Keywords: grain growth, mesoscale, algorithm, dissipative system, Mullins Equation, Herring. Here we exhibit a consistent variational approach to the mesoscale simulation of large systems of grain

  20. Coarse-grained computations for a micellar system Dmitry I. Kopelevich,a)

    E-Print Network [OSTI]

    Coarse-grained computations for a micellar system Dmitry I. Kopelevich,a) Athanassios Z establish, through coarse-grained computation, a connection between traditional, continuum numerical-grained mesoscopic observables of the Monte Carlo simulation, and on computational time scale separation between

  1. Formation of wood grain: self-organization through alignment of elongated cells II

    E-Print Network [OSTI]

    van Gaans, Onno

    Formation of wood grain: self-organization through alignment of elongated cells II Roeland Merks-like textures of wood (see Figure 1). These textures, called wood grain, form as new, elongated cells that are deposited on top of the existing wood in the vascular cambium, and align with the existing wood grain

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

    E-Print Network [OSTI]

    Motta, Arthur T.

    A thermal spike model of grain growth under irradiation D. Kaoumi,1,a A. T. Motta,1 and R. C The experimental study of grain growth in nanocrystalline metallic foils under ion irradiation showed the existence of a low-temperature regime below about 0.15­0.22Tm , where grain growth is independent of the irradiation

  3. Mechanism of grain growth during severe plastic deformation of a nanocrystalline NiFe alloy

    E-Print Network [OSTI]

    Zhu, Yuntian T.

    National Laboratory, Los Alamos, New Mexico 87545, USA 3 Australian Key Centre for Microscopy migration is re- sponsible for the nc grain growth. Experimental results ob- tained via in situ transmission mechanism--stress coupled grain-boundary migration; i.e., a grain grows at the expense of other neighboring

  4. Structure and Chemistry of Yttria-Stabilized Cubic-Zirconia Symmetric Tilt Grain Boundaries

    E-Print Network [OSTI]

    Pennycook, Steve

    Structure and Chemistry of Yttria-Stabilized Cubic-Zirconia Symmetric Tilt Grain Boundaries boundaries in yttria-stabilized cubic-zirconia, 5 (310) and near- 13 (510), are studied by Z [001] symmetric tilt grain boundaries in yttria-stabilized cubic-zirconia (YSZ). The grain boundaries

  5. Mesoscale Simulation of Grain David Kinderlehrer, Jeehyun Lee, Irene Livshits and Shlomo Ta'asan

    E-Print Network [OSTI]

    Mesoscale Simulation of Grain Growth David Kinderlehrer, Jeehyun Lee, Irene Livshits and Shlomo Ta'asan WILEY-VCH Verlag Berlin GmbH September 4, 2003 #12;2 0.1 Introduction The mesoscale simulation of grain of the statistics it provides, we are led to the companion issue of coarse graining in mesoscale simulations. We

  6. Asymptotic Interference Alignment for Exact Repair in Distributed Storage Systems

    E-Print Network [OSTI]

    Jafar, Syed A.

    Asymptotic Interference Alignment for Exact Repair in Distributed Storage Systems Viveck R. Cadambe consider a distributed storage system where a file of size M is stored in n distributed storage nodes using of this paper is to repair failed nodes in the storage system, by replacing them by their replicas (exact repair

  7. Ground Versus Unground Grain for Lactating Dairy Cows. 

    E-Print Network [OSTI]

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

    1936-01-01

    LIBRARY, A & hf COLLEGE, CAMPUS. TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIFkECTOR COLLE~E STATION, BRAZOS COUNTY, TEXAS BULLETIN NO. 530 SEPTEMBER, 193 6 DIVISION OF DAIRY HUSBANDRY Ground Versus Unground Grain far Lactating...- bandry in cooperation with the Texas Agricultural Experiment Station. The double reversal method of feeding lactating dairy cows was used in comparing whole versus ground shelled corn, whole versus ground threshed oats, whole versus ground threshed...

  8. Entrainment of coarse grains using a discrete particle model

    SciTech Connect (OSTI)

    Valyrakis, Manousos; Arnold, Roger B. Jr.

    2014-10-06

    Conventional bedload transport models and incipient motion theories relying on a time-averaged boundary shear stress are incapable of accounting for the effects of fluctuating near-bed velocity in turbulent flow and are therefore prone to significant errors. Impulse, the product of an instantaneous force magnitude and its duration, has been recently proposed as an appropriate criterion for quantifying the effects of flow turbulence in removing coarse grains from the bed surface. Here, a discrete particle model (DPM) is used to examine the effects of impulse, representing a single idealized turbulent event, on particle entrainment. The results are classified according to the degree of grain movement into the following categories: motion prior to entrainment, initial dislodgement, and energetic displacement. The results indicate that in all three cases the degree of particle motion depends on both the force magnitude and the duration of its application and suggest that the effects of turbulence must be adequately accounted for in order to develop a more accurate method of determining incipient motion. DPM is capable of simulating the dynamics of grain entrainment and is an appropriate tool for further study of the fundamental mechanisms of sediment transport.

  9. Three-body interactions in complex fluids: Virial coefficients from simulation finite-size effects

    SciTech Connect (OSTI)

    Ashton, Douglas J.; Wilding, Nigel B.

    2014-06-28

    A simulation technique is described for quantifying the contribution of three-body interactions to the thermodynamical properties of coarse-grained representations of complex fluids. The method is based on a new approach for determining virial coefficients from the measured volume-dependent asymptote of a certain structural function. By comparing the third virial coefficient B{sub 3} for a complex fluid with that of an approximate coarse-grained model described by a pair potential, three body effects can be quantified. The strategy is applicable to both Molecular Dynamics and Monte Carlo simulation. Its utility is illustrated via measurements of three-body effects in models of star polymers and in highly size-asymmetrical colloid-polymer mixtures.

  10. light-Scattering and Size-Exclusion Chromatographic.' Characterization of Hydroxyethyl Cellulose Acetate

    E-Print Network [OSTI]

    Wu, Chi

    light-Scattering and Size-Exclusion Chromatographic.' Characterization of Hydroxyethyl Cellulose to investigate a set of moderately distributed hydroxyethyl cellulose acetate{~ECA) samples'in tetrahydrofuran- Cellulose constitutes a ubiquitous and r~newable ular weight~ndcm9l~cular weight distribution:"". natural

  11. MIXING AND TRANSPORT OF SHORT-LIVED AND STABLE ISOTOPES AND REFRACTORY GRAINS IN PROTOPLANETARY DISKS

    SciTech Connect (OSTI)

    Boss, Alan P.

    2013-08-10

    Analyses of primitive meteorites and cometary samples have shown that the solar nebula must have experienced a phase of large-scale outward transport of small refractory grains as well as homogenization of initially spatially heterogeneous short-lived isotopes. The stable oxygen isotopes, however, were able to remain spatially heterogeneous at the {approx}6% level. One promising mechanism for achieving these disparate goals is the mixing and transport associated with a marginally gravitationally unstable (MGU) disk, a likely cause of FU Orionis events in young low-mass stars. Several new sets of MGU models are presented that explore mixing and transport in disks with varied masses (0.016 to 0.13 M{sub Sun }) around stars with varied masses (0.1 to 1 M{sub Sun }) and varied initial Q stability minima (1.8 to 3.1). The results show that MGU disks are able to rapidly (within {approx}10{sup 4} yr) achieve large-scale transport and homogenization of initially spatially heterogeneous distributions of disk grains or gas. In addition, the models show that while single-shot injection heterogeneity is reduced to a relatively low level ({approx}1%), as required for early solar system chronometry, continuous injection of the sort associated with the generation of stable oxygen isotope fractionations by UV photolysis leads to a sustained, relatively high level ({approx}10%) of heterogeneity, in agreement with the oxygen isotope data. These models support the suggestion that the protosun may have experienced at least one FU Orionis-like outburst, which produced several of the signatures left behind in primitive chondrites and comets.

  12. Small-angle neutron scattering measurement of deuterium trapping at dislocations and grain boundaries in palladium

    SciTech Connect (OSTI)

    Heuser, B.J.

    1991-01-01

    Small angle neutron scattering measurements have been performed on deformed single and polycrystalline palladium with and without deuterium dissolved in the solution phase at room temperature. The purpose of these experiments was to directly measure the spatial distribution of trapped deuterium at dislocations in the deformed metal. The net scattering cross section for the same smaple with and without deuterium shows a behavior expected from deuterium correlation with dislocations froming rod-like scattering structures. The measured cross sections indicate the trapped deuterium is within 2 to 3 Burgers vectors of the dislocation core. On average 1 to 3 deuterons per {angstrom} are trapped at the dislocations in the deformed samples. The measurements also indicate the straight, rod-like correlation geometry extends on average 50 to 100 {angstrom} along the dislocations. Dislocation densities on the order of 5 {times} 10{sup 11} cm/cm{sup 3} were found for all samples investigated. Net scattering from a well annealed polycrystalline palladium sample exhibiting a behavior expected from spherical shells has been observed. This net scattering is attributed to deuterium trapping at grain boundaries in the polycrystalline sample. net scattering in excess of that expected from deuterium correlated at dislocations was also observed in a deformed polycrystalline measurement. This too is attributed to deuterium trapping at grain boundaries. The dislocation substructure of the deformed palladium samples was characterized by transmission electron microscopy (TEM). This analysis illustrated the cellular arrangement that evolved in palladium during cold working. The presence of MnO particles also was confirmed by TEM analysis.

  13. Investigation of the Distribution of Fission Products Silver, Palladium and Cadmium in Neutron Irradiated SIC using a Cs Corrected HRTEM

    SciTech Connect (OSTI)

    I. J. van Rooyen; E. Olivier; J. H Neethlin

    2014-10-01

    Electron microscopy examinations of selected coated particles from the first advanced gas reactor experiment (AGR-1) at Idaho National Laboratory (INL) provided important information on fission product distribution and chemical composition. Furthermore, recent research using STEM analysis led to the discovery of Ag at SiC grain boundaries and triple junctions. As these Ag precipitates were nano-sized, high resolution transmission electron microscopy (HRTEM) examination was used to provide more information at the atomic level. This paper describes some of the first HRTEM results obtained by examining a particle from Compact 4-1-1, which was irradiated to an average burnup of 19.26% fissions per initial metal atom (FIMA), a time average, volume-averaged temperature of 1072°C; a time average, peak temperature of 1182°C and an average fast fluence of 4.13 x 1021 n/cm2. Based on gamma analysis, it is estimated that this particle may have released as much as 10% of its available Ag-110m inventory during irradiation. The HRTEM investigation focused on Ag, Pd, Cd and U due to the interest in Ag transport mechanisms and possible correlation with Pd, Ag and U previously found. Additionally, Compact 4-1-1 contains fuel particles fabricated with a different fuel carrier gas composition and lower deposition temperatures for the SiC layer relative to the Baseline fabrication conditions, which are expected to reduce the concentration of SiC defects resulting from uranium dispersion. Pd, Ag, and Cd were found to co-exist in some of the SiC grain boundaries and triple junctions whilst U was found to be present in the micron-sized precipitates as well as separately in selected areas at grain boundaries. This study confirmed the presence of Pd both at inter- and intragranular positions; in the latter case specifically at stacking faults. Small Pd nodules were observed at a distance of about 6.5 micron from the inner PyC/SiC interface.

  14. Distributed Theorem Proving for Distributed Hybrid Systems

    E-Print Network [OSTI]

    Platzer, André

    system with a varying number of arbitrarily many cars. 1 Introduction Hybrid systems with joint discrete a multi-agent system, e.g., distributed car control systems. Such systems form distributed hybrid systemsDistributed Theorem Proving for Distributed Hybrid Systems David W. Renshaw, Sarah M. Loos

  15. Seasonal Run Distribution Seasonal Run Distribution

    E-Print Network [OSTI]

    . The term "total run" defines the number of adult sockeye salmon that home to the Karluk River before197 Seasonal Run Distribution CHAPTER 6 Seasonal Run Distribution They arrived from the sea in one, what was the seasonal run distribution of its sockeye salmon? Was the original run distribution which

  16. Bivariate Generalized Exponential Distribution

    E-Print Network [OSTI]

    Kundu, Debasis

    Bivariate Generalized Exponential Distribution Debasis Kundu and Rameshwar D. Gupta Abstract Recently it is observed that the generalized exponential distribution can be used quite effectively exponential distribution so that the marginals have generalized exponential distributions. It is observed

  17. Introduction Constrained distribution

    E-Print Network [OSTI]

    Nuel, Gregory

    Introduction Constrained distribution Observed pattern distribution Counting patterns-9 September 2009 G. Nuel Counting patterns in degenerated sequences #12;Introduction Constrained distribution Observed pattern distribution Outline 1 Introduction Special letters in biological sequences Counting

  18. Spectroscopic study of the Moses Lake dune field, Washington: Determination of compositional distributions and source lithologies

    E-Print Network [OSTI]

    Bandfield, Joshua L.

    Spectroscopic study of the Moses Lake dune field, Washington: Determination of compositional Coulee, dune samples, and clast deposits. Factor analysis, target transformation, and end-member recovery techniques were applied to the set of dune samples as well as a set of grain size fractions. The dune sample

  19. Gorzkowski et al. 1 Changes in the Distribution of Interfaces in PMN-35 mol% PT as a Function of Time

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    Gorzkowski et al. 1 Changes in the Distribution of Interfaces in PMN- 35 mol% PT as a Function-3890 Abstract The crystallographic distribution of surfaces surrounding grains in PMN- 35 mol% PT has been to solid- state growth methods demonstrated in Al2O3 11 and BaTiO3.12 Growth of PMN-35PT single crystals

  20. Double-distribution-function discrete Boltzmann model for combustion

    E-Print Network [OSTI]

    Chuandong Lin; Aiguo Xu; Guangcai Zhang; Yingjun Li

    2015-11-11

    A 2-dimensional discrete Boltzmann model for combustion is presented. Mathematically, the model is composed of two coupled discrete Boltzmann equations for two species and a phenomenological equation for chemical reaction process. Physically, the model is equivalent to a reactive Navier-Stokes model supplemented by a coarse-grained model for the thermodynamic nonequilibrium behaviours. This model adopts 16 discrete velocities. It works for both subsonic and supersonic combustion phenomena with flexible specific heat ratio. To discuss the physical accuracy of the coarse-grained model for nonequilibrium behaviours, three other discrete velocity models are used for comparisons. Numerical results are compared with analytical solutions based on both the first-order and second-order truncations of the distribution function. It is confirmed that the physical accuracy increases with the increasing moment relations needed by nonequlibrium manifestations. Furthermore, compared with the single distribution function model, this model can simulate more details of combustion.

  1. Discrete multivariate distributions

    E-Print Network [OSTI]

    Oleg Yu. Vorobyev; Lavrentiy S. Golovkov

    2011-02-22

    This article brings in two new discrete distributions: multidimensional Binomial distribution and multidimensional Poisson distribution. Those distributions were created in eventology as more correct generalizations of Binomial and Poisson distributions. Accordingly to eventology new laws take into account full distribution of events. Also, in article its characteristics and properties are described

  2. On-Farm Storage and Disposal of Sorghum Grain

    E-Print Network [OSTI]

    Brown, Charles W.; Moore, Clarence A.

    1963-01-01

    handspray to fumigate. Slightly less than half in the Coastal Bend used their aeration systems and one-third used handsprays. Insects are a major problem of farm storage, and farmers were not successful entirely in control prac- tices. -,- Insects... constituted 18 percent of the reasons for loss in the High Plains, 40 percent in the North Central area and 60 percent in the Coastal Bend. Adequacy of Practices to Maintain Quality The adequacy of quality control practices for farm-stored sorghum grain...

  3. Low temperature production of large-grain polycrystalline semiconductors

    DOE Patents [OSTI]

    Naseem, Hameed A. (Fayetteville, AR); Albarghouti, Marwan (Loudonville, NY)

    2007-04-10

    An oxide or nitride layer is provided on an amorphous semiconductor layer prior to performing metal-induced crystallization of the semiconductor layer. The oxide or nitride layer facilitates conversion of the amorphous material into large grain polycrystalline material. Hence, a native silicon dioxide layer provided on hydrogenated amorphous silicon (a-Si:H), followed by deposited Al permits induced crystallization at temperatures far below the solid phase crystallization temperature of a-Si. Solar cells and thin film transistors can be prepared using this method.

  4. Ratooning Grain Sorghum on the Texas Gulf Coast 

    E-Print Network [OSTI]

    Livingston, Stephen; Coffman, Cloyce G.

    1997-01-03

    , there is an opportunity to earn some additional income while multiplying the humus/residue production with an additional top crop. Grain sorghum is a logical cover crop when it is considered that vegetables return, but a small amount of humus and haygrazers require full... a factor of how early the main crop was planted and harvested, enabling the second crop to proceed under favorable conditions. Dry weather and high temperatures will slow juvenile growth and will reduce bloom set. In 1996 (drought year), heavy rains...

  5. Grain Scale Modeling of Arbitrary Fluid Saturation in Random Packings

    E-Print Network [OSTI]

    Konstantin Melnikov; Roman Mani; Falk K. Wittel; Marcel Thielmann; Hans J. Herrmann

    2015-03-25

    We propose a model for increasing liquid saturation in a granular packing which can account for liquid redistribution at saturation levels beyond the well-studied capillary bridge regime. The model is capable of resolving and combining capillary bridges, menisci and fully saturated pores to form local liquid clusters of any shape. They can exchange volume due to the local Laplace pressure gradient via a liquid film on the surfaces of grains. Local instabilities like Haines jumps trigger the discontinuous evolution of the liquid front. The applicability of the model is demonstrated and compared to benchmark experiments on the level of individual liquid structures as well as on larger systems.

  6. Grain - A Java Analysis Framework for Total Data Readout

    E-Print Network [OSTI]

    P. Rahkila

    2007-11-21

    Grain is a data analysis framework developed to be used with the novel Total Data Readout data acquisition system. In Total Data Readout all the electronics channels are read out asynchronously in singles mode and each data item is timestamped. Event building and analysis has to be done entirely in the software post-processing the data stream. A flexible and efficient event parser and the accompanying software framework have been written entirely in Java. The design and implementation of the software are discussed along with experiences gained in running real-life experiments.

  7. Small Grains and Rye Grass for Winter Pasture. 

    E-Print Network [OSTI]

    Stansel, R. H. (Roy Harrison); Dunkle, P. B. (Paul Burtch); Jones, D. L. (Don L.)

    1937-01-01

    as lvell as practicaIIg all classes of livestock. With the uniform success of Sudan as grazing crop in sumlner and fall and with these winter grazillg crops, tile farmer has within his wasp a potential constant supply of green grafiag abundant proteins... cutting to cutting, but has a tendency to increase during the latter part of the growing season. RESULTS AT DENTON Pract.ica1 Problems in Connection with Winter Pastures at Denton Wheat is the principal small grain planted for winter pasture although...

  8. Hydrocracking process using disparate catalyst particle sizes

    SciTech Connect (OSTI)

    Kukes, S.G.; Miller, J.T.; Gutberlet, L.C.; Kelterboro, J.C

    1989-05-30

    This patent describes a process for the hydrocracking of a hydrocarbon feedstock which comprises reacting the feedstock with hydrogen at hydrocracking conversion conditions in a plurality of reaction zones in series containing hydrocracking catalyst wherein at least one of the reaction zones contains a small nominal size hydrocracking catalyst wherein the small nominal size catalyst has a U.S. sieve mesh size ranging from about 10 to about 16, and wherein at least one reaction zone upstream of the reaction zone containing the small nominal size hydrocracking catalyst having a particle size greater than the small nominal size hydrocracking catalyst.

  9. GASIFICATION FOR DISTRIBUTED GENERATION

    SciTech Connect (OSTI)

    Ronald C. Timpe; Michael D. Mann; Darren D. Schmidt

    2000-05-01

    A recent emphasis in gasification technology development has been directed toward reduced-scale gasifier systems for distributed generation at remote sites. The domestic distributed power generation market over the next decade is expected to be 5-6 gigawatts per year. The global increase is expected at 20 gigawatts over the next decade. The economics of gasification for distributed power generation are significantly improved when fuel transport is minimized. Until recently, gasification technology has been synonymous with coal conversion. Presently, however, interest centers on providing clean-burning fuel to remote sites that are not necessarily near coal supplies but have sufficient alternative carbonaceous material to feed a small gasifier. Gasifiers up to 50 MW are of current interest, with emphasis on those of 5-MW generating capacity. Internal combustion engines offer a more robust system for utilizing the fuel gas, while fuel cells and microturbines offer higher electric conversion efficiencies. The initial focus of this multiyear effort was on internal combustion engines and microturbines as more realistic near-term options for distributed generation. In this project, we studied emerging gasification technologies that can provide gas from regionally available feedstock as fuel to power generators under 30 MW in a distributed generation setting. Larger-scale gasification, primarily coal-fed, has been used commercially for more than 50 years to produce clean synthesis gas for the refining, chemical, and power industries. Commercial-scale gasification activities are under way at 113 sites in 22 countries in North and South America, Europe, Asia, Africa, and Australia, according to the Gasification Technologies Council. Gasification studies were carried out on alfalfa, black liquor (a high-sodium waste from the pulp industry), cow manure, and willow on the laboratory scale and on alfalfa, black liquor, and willow on the bench scale. Initial parametric tests evaluated through reactivity and product composition were carried out on thermogravimetric analysis (TGA) equipment. These tests were evaluated and then followed by bench-scale studies at 1123 K using an integrated bench-scale fluidized-bed gasifier (IBG) which can be operated in the semicontinuous batch mode. Products from tests were solid (ash), liquid (tar), and gas. Tar was separated on an open chromatographic column. Analysis of the gas product was carried out using on-line Fourier transform infrared spectroscopy (FT-IR). For selected tests, gas was collected periodically and analyzed using a refinery gas analyzer GC (gas chromatograph). The solid product was not extensively analyzed. This report is a part of a search into emerging gasification technologies that can provide power under 30 MW in a distributed generation setting. Larger-scale gasification has been used commercially for more than 50 years to produce clean synthesis gas for the refining, chemical, and power industries, and it is probable that scaled-down applications for use in remote areas will become viable. The appendix to this report contains a list, description, and sources of currently available gasification technologies that could be or are being commercially applied for distributed generation. This list was gathered from current sources and provides information about the supplier, the relative size range, and the status of the technology.

  10. Microstructural effects on capacity-rate performance of vanadium oxide cathodes in lithium-ion batteries

    E-Print Network [OSTI]

    Davis, Robin M. (Robin Manes)

    2005-01-01

    Vanadium oxide thin film cathodes were analyzed to determine whether smaller average grain size and/or a narrower average grain size distribution affects the capacity-rate performance in lithium-ion batteries. Vanadium ...

  11. Evaluating Aeolian Sand Transport Vectors In Dune Blowouts 

    E-Print Network [OSTI]

    Randolph, Janelle

    2013-02-13

    Grain size distribution is the reflection of the feedback between sediment transport system and morphologic change of beach systems. In this respect, early models suggest that grain size can be used to determine the transport vectors. However...

  12. Copyright (to be inserted by the publisher ) Mesoscale Simulation of the Evolution of the Grain Boundary Character

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    Citation & Copyright (to be inserted by the publisher ) Mesoscale Simulation of the Evolution; Simulation; Grain boundary energy; Mullins Equation Abstract. A mesoscale, variational simulation of grain to the mesoscale simulation of grain growth in large two dimensional systems to study the evolution of the grain

  13. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K???Bi???TiO?-BaTiO?-Na???Bi???TiO? piezoelectric materials

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

    Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

    2015-02-26

    We synthesized grain-oriented lead-free piezoelectric materials in (K???Bi???TiO?-BaTiO?-xNa???Bi???TiO? (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d?? ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectricmore »materials.« less

  14. Phase-retrieval X-ray microscopy by Wigner-distribution deconvolution

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

    Chapman, Henry, N.

    2014-10-30

    64x64 scan of a group of latex spheres with 45 nm step size, used for demonstrating Wigner-distribution deconvolution.

  15. Top 9 Things You Didn't Know About Distributed Wind Power | Department...

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

    by households, schools, farms, industrial facilities and municipalities, distributed wind doesn't only refer to small-scale turbines; it includes any size turbine or array of...

  16. Top 10 Things You Didn't Know About Distributed Wind Power |...

    Energy Savers [EERE]

    by households, schools, farms, industrial facilities and municipalities, distributed wind doesn't only refer to small-scale turbines; it includes any size turbine or array of...

  17. Grasses and Forage Plants: a Study of Composition and Value; Texas Grains: Composition ; Ash Analyses, Grasses and Grains

    E-Print Network [OSTI]

    Harrington, H. H. (Henry Hill)

    1892-01-01

    . ALFALFA-LTCERSE. (Medicago Satiz.~.) "JVhen brought from South America to the United States, it was supposed to be a new plant, and called 'Brazilian Clover.' A few years ago it was taken from Western South America to California, and thence... amount of Amide Nitrogen is also quite no-. ,ble. The albuminoids are higher than in clover, and about the : as incow pea vines. It is remarkable how well the plant support's es, cattle and hogs. I believe it can come nearer replacing grain .ely than...

  18. Simulating the Entropic Collapse of Coarse-Grained Chromosomes

    E-Print Network [OSTI]

    Tyler N. Shendruk; Martin Bertrand; Hendrick W. de Haan; James L. Harden; Gary W. Slater

    2014-11-16

    Depletion forces play a role in the compaction and de-compation of chromosomal material in simple cells but it remains debatable whether they are sufficient to account for chromosomal collapse. We present coarse-grained molecular dynamics simulations, which reveal that depletion-induced attraction is sufficient to cause the collapse of a flexible chain of large structural monomers immersed in a bath of smaller depletants. These simulations use an explicit coarse-grained computational model that treats both the supercoiled DNA structural monomers and the smaller protein crowding agents as combinatorial, truncated Lennard-Jones spheres. By presenting a simple theoretical model, we quantitatively cast the action of depletants on supercoiled bacterial DNA as an effective solvent quality. The rapid collapse of the simulated flexible chromosome at the predicted volume fraction of depletants is a continous phase transition. Additional physical effects to such simple chromosome models, such as enthalpic interactions between structural monomers or chain rigidity, are required if the collapse is to be a first-order phase transition.

  19. Experimental comparison of various techniques for spot size measurement of high-energy x-ray source

    E-Print Network [OSTI]

    Wang, Yi; Chen, Nan; Cheng, Jinming; Li, Chenggang; Dai, Wenhua; Li, Hong; Long, Quanhong; Shi, Jinshui; Deng, Jianjun

    2015-01-01

    In the experiment of flash-radiography, the quality of acquired image strongly depends on the focal size of the x-ray source spot. A variety of techniques based on imaging of pinhole, slit and rollbar are adopted to measure the focal spot size of the Dragon-I linear induction accelerator. The image of pinhole provides a two-dimensional distribution of the x-ray spot, while those of slit and rollbar give a line-spread distribution and an edge-spread distribution, respectively. The spot size characterized by full-width at half-maximum and that characterized by the LANL definition are calculated for comparison.

  20. Software implemented fault-tolernace on distributed-memory MIMD architectures 

    E-Print Network [OSTI]

    Holland, Gavin D

    1995-01-01

    Large multicomputer systems are inherently unreliable because of their enormous complexity. This has a direct impact on distributed computations performed on these systems. As the size and execution time of these distributed computations grows, so...

  1. Distributed anonymous function computation in information fusion and multiagent systems

    E-Print Network [OSTI]

    Hendrickx, Julien

    We propose a model for deterministic distributed function computation by a network of identical and anonymous nodes, with bounded computation and storage capabilities that do not scale with the network size. Our goal is ...

  2. 2012 Market Report on Wind Technologies in Distributed Applications

    SciTech Connect (OSTI)

    Orrell, Alice C.

    2013-08-01

    An annual report on U.S. wind power in distributed applications – expanded to include small, mid-size, and utility-scale installations – including key statistics, economic data, installation, capacity, and generation statistics, and more.

  3. Areas of contact and pressure distribution in bolted joints

    E-Print Network [OSTI]

    Gould, Herbert Hirsch

    1970-01-01

    When two plates are bolted (or riveted) together these will be in contact in the immediate vicinity of the bolt heads and separated beyond it. The pressure distribution and size of the contact zone is of considerable ...

  4. Semicontinuous Sized Types and Termination Andreas Abel #

    E-Print Network [OSTI]

    Abel, Andreas

    , and classical applications are total correctness and termination of partial evaluation. In languagesSemi­continuous Sized Types and Termination Andreas Abel # Institut für Informatik Ludwig to termination uses sized types: an ordinal bound for the size of a data structure is stored in its type

  5. Drying and Its Effects on the Milling Characteristics of Sorghum Grain

    E-Print Network [OSTI]

    1949-01-01

    . ....... Martin. ....... Martin. ....... Martin. ....... Martin. ....... ....... Martin. ....... Martin. Martin. ....... ....... Martin. TABLE 3. GENERAL INFORMATION Dryjng L ir temperature, deg. F. Air velocity, feet Per minuteZ Moisture content... and natural gas fuel were approximately 20 cents for grain with 14 to 16 percent moisture; 25 cents for 17 to 20 percent moisture grain; and 40 cents for grain with 21 to 24 percent moisture. Martin, with a moisture content up to 20 percent, was dried...

  6. A comparison of silage and grain yields of four corn hybrids at three locations in Texas 

    E-Print Network [OSTI]

    Martelino, Rafael Agcaoili

    1954-01-01

    TABLES Page 20 31 Analysis of variance of silage yields at Temple Analysis of variance of grain yields at Temple . Analysis of varianoe of lodging percentage at Temple. . . ~ 12 o ~ 12 ~ i 13 4, 5 ~ 6, 70 Silage yield, grain yield... and lodging percentage of four oorn bybrids and three spaoings, Temple . Analysis of variance of silage yields at Tyler . Analysis of varianoe of grain yields at Tyler Analysis of variance oi' lodging peroemtage at Tyler 13 16 16 ~ 0 17 Silage yield...

  7. A comparison of silage and grain yields of four corn hybrids at three locations in Texas 

    E-Print Network [OSTI]

    Spears, Ben Riley

    1953-01-01

    A))'I H. '" C I'I OH ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ o ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 40 AILNHIX o ~ ~ ~ ~ ~ ~ ~ ~ ~ o ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ o oo IT 42 1, Ccsibined silage yields grain yield and lodging percentage of the four hybrids for all locations? 2...? Ceabined silage yields grain yield and lodging percentage of the three plant spacdngs for all locations, TABLES Analysis of variance of silage yields at College Station. Analysis of vsr1mme of grain yields at GoUege Statics& 30 4. Analysis...

  8. Prior distribution Andrew Gelman

    E-Print Network [OSTI]

    Gelman, Andrew

    Prior distribution Andrew Gelman Volume 3, pp 1634­1637 in Encyclopedia of Environmetrics (ISBN, 2002 #12;Prior distribution The prior distribution is a key part of Bayesian infer- ence (see Bayesian with the probability distribution of new data to yield the posterior distribution, which in turn is used for future

  9. Three-dimensional dust-ion-acoustic rogue waves in a magnetized dusty pair-ion plasma with nonthermal nonextensive electrons and opposite polarity dust grains

    SciTech Connect (OSTI)

    Guo, Shimin Mei, Liquan

    2014-08-15

    Dust-ion-acoustic (DIA) rogue waves are investigated in a three-dimensional magnetized plasma containing nonthermal electrons featuring Tsallis distribution, both positive and negative ions, and immobile dust grains having both positive and negative charges. Via the reductive perturbation method, a (3?+?1)-dimensional nonlinear Schrödinger (NLS) equation is derived to govern the dynamics of the DIA wave packets. The modulation instability of DIA waves described by the (3?+?1)-dimensional NLS equation is investigated. By means of the similarity transformation and symbolic computation, both the first- and second-order rogue wave solutions of the (3?+?1)-dimensional NLS equation are constructed in terms of rational functions. Moreover, the dynamics properties and the effects of plasma parameters on the nonlinear structures of rogue waves are discussed in detail. The results could be useful for understanding the physical mechanism of rogue waves in laboratory experiments where pair-ion plasmas with electrons and dust grains can be found.

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

    E-Print Network [OSTI]

    Fuller, Stephen W.; Paggi, Mechel S.

    1978-01-01

    by six class I rail- roads. During the study period, the Santa Fe carried ap- proximately one-third of the inbound grain cars and the Rock Island about one-fourth. The Ft. Worth and Den- @ ver, Missouri-Kansas-Texas, Missouri Pacific, and Southern... Pacific carried 14, 14, 12, and 3 percent of the respective inbound grain traffic. The average quantity of grain per car was about 3,200 bushels, and the average haul was 669 miles. It is estimated that 69,517 grain cars were unloaded during the 12...

  11. Grain Boundary Percolation Modeling of Fission Gas Release in Oxide Fuels

    SciTech Connect (OSTI)

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

    2012-05-01

    We present a new approach to fission gas release modeling in oxide fuels based on grain boundary network percolation. The method accounts for variability in the bubble growth and coalescence rates on individual grain boundaries, and the resulting effect on macroscopic fission gas release. Two-dimensional representa- tions of fuel pellet microstructures are considered, and the resulting gas release rates are compared with traditional two-stage Booth models, which do not account for long-range percolation on grain boundary net- works. The results show that the requirement of percolation of saturated grain boundaries can considerably reduce the total gas release rates, particularly when gas resolution is considered.

  12. Grain boundary chemistry effects on environment-induced crack growth of iron-based alloys

    SciTech Connect (OSTI)

    Jones, R.H.

    1992-11-01

    Relation between grain boundary chemistry and environment-induced crack growth of Fe-based alloys is reviewed. The importance of the cleanliness of steels is clearly demonstrated by direct relations between grain boundary chemistry and crack growth behavior for both H and anodic dissolution-induced crack growth. Relationships between strain to failure, work of fracture, K[sub ISCC], crack velocity and fracture mode and grain boundary chemistry are presented. Only results in which the grain boundary chemistry has been measured directly by Auger electron spectroscopy (AES) on intergranular surfaces exposed by in situ fracture have been considered in this review.

  13. Grain boundary chemistry effects on environment-induced crack growth of iron-based alloys

    SciTech Connect (OSTI)

    Jones, R.H.

    1992-11-01

    Relation between grain boundary chemistry and environment-induced crack growth of Fe-based alloys is reviewed. The importance of the cleanliness of steels is clearly demonstrated by direct relations between grain boundary chemistry and crack growth behavior for both H and anodic dissolution-induced crack growth. Relationships between strain to failure, work of fracture, K{sub ISCC}, crack velocity and fracture mode and grain boundary chemistry are presented. Only results in which the grain boundary chemistry has been measured directly by Auger electron spectroscopy (AES) on intergranular surfaces exposed by in situ fracture have been considered in this review.

  14. A fast grain-growth mechanism revealed in nanocrystalline ceramic-oxides

    SciTech Connect (OSTI)

    Aidhy, Dilpuneet S; Zhang, Yanwen; Weber, William J

    2014-01-01

    Grain growth problem in nanocrystalline ceramic-oxides renders their highly attractive properties practically unusable due to limited understanding on the underlying grain growth mechanisms. Two conventional 'slow' grain-growth mechanisms, i.e., curvature-driven and grainrotation driven, are shown to be thermally active, and the discovery of a 'fast' disorder-driven mechanism is revealed using molecular dynamics simulation on nanocrystalline ceria, in conjunction with experimental observations. We elucidate that this disorder mechanism drives the unexpected fast grain growth observed experimentally during synthesis and irradiation conditions.

  15. Mesoscale Theory of Grains and Cells: Crystal Plasticity and Coarsening Surachate Limkumnerd* and James P. Sethna

    E-Print Network [OSTI]

    Sethna, James P.

    Mesoscale Theory of Grains and Cells: Crystal Plasticity and Coarsening Surachate Limkumnerd a mesoscale theory of dislocation motion. It provides a quantitative description of deformation and rotation

  16. The Plant Variety Protection Act: Information for Texas Small Grain Producers 

    E-Print Network [OSTI]

    Brown, Steve; Morgan, Gaylon

    2005-01-26

    This publication explains the provision of the Plant Variety Protection Act and its amendments. It focuses on the PVPA's application to small grain producers....

  17. Hazards of explosives dusts: Particle size effects

    SciTech Connect (OSTI)

    Cashdollar, K L; Hertzberg, M; Green, G M

    1992-02-01

    At the request of the Department of Energy, the Bureau of Mines has investigated the hazards of military explosives dispersed as dust clouds in a 20-L test chamber. In this report, the effect of particle size for HMX, HNS, RDX, TATB, and TNT explosives dusts is studied in detail. The explosibility data for these dusts are also compared to those for pure fuel dusts. The data show that all of the sizes of the explosives dusts that were studied were capable of sustaining explosions as dust clouds dispersed in air. The finest sizes (<10 [mu]m) of explosives dusts were less reactive than the intermediate sizes (20 to 60 [mu]m); this is opposite to the particle size effect observed previously for the pure fuel dusts. At the largest sizes studied, the explosives dusts become somewhat less reactive as dispersed dust clouds. The six sizes of the HMX dust were also studied as dust clouds dispersed in nitrogen.

  18. Simultaneous regulation of cell size and chromosome replication in bacteria

    E-Print Network [OSTI]

    Po-Yi Ho; Ariel Amir

    2015-07-24

    Bacteria are able to maintain a narrow distribution of cell sizes by regulating the timing of cell divisions. In rich nutrient conditions, cells divide much faster than their chromosomes replicate. This implies that cells maintain multiple rounds of chromosome replication per cell division by regulating the timing of chromosome replications. Here, we show that both cell size and chromosome replication may be simultaneously regulated by the long-standing initiator accumulation strategy. The strategy proposes that initiators are produced in proportion to the volume increase and is accumulated at each origin of replication, and chromosome replication is initiated when a critical amount per origin has accumulated. We show that this model maps to the incremental model of size control, which was previously shown to reproduce experimentally observed correlations between various events in the cell cycle and explains the exponential dependence of cell size on the growth rate of the cell. Furthermore, we show that this model also leads to the efficient regulation of the timing of initiation and the number of origins consistent with existing experimental results.

  19. Integrated Transmission and Distribution Control

    SciTech Connect (OSTI)

    Kalsi, Karanjit; Fuller, Jason C.; Tuffner, Francis K.; Lian, Jianming; Zhang, Wei; Marinovici, Laurentiu D.; Fisher, Andrew R.; Chassin, Forrest S.; Hauer, Matthew L.

    2013-01-16

    Distributed, generation, demand response, distributed storage, smart appliances, electric vehicles and renewable energy resources are expected to play a key part in the transformation of the American power system. Control, coordination and compensation of these smart grid assets are inherently interlinked. Advanced control strategies to warrant large-scale penetration of distributed smart grid assets do not currently exist. While many of the smart grid technologies proposed involve assets being deployed at the distribution level, most of the significant benefits accrue at the transmission level. The development of advanced smart grid simulation tools, such as GridLAB-D, has led to a dramatic improvement in the models of smart grid assets available for design and evaluation of smart grid technology. However, one of the main challenges to quantifying the benefits of smart grid assets at the transmission level is the lack of tools and framework for integrating transmission and distribution technologies into a single simulation environment. Furthermore, given the size and complexity of the distribution system, it is crucial to be able to represent the behavior of distributed smart grid assets using reduced-order controllable models and to analyze their impacts on the bulk power system in terms of stability and reliability. The objectives of the project were to: • Develop a simulation environment for integrating transmission and distribution control, • Construct reduced-order controllable models for smart grid assets at the distribution level, • Design and validate closed-loop control strategies for distributed smart grid assets, and • Demonstrate impact of integrating thousands of smart grid assets under closed-loop control demand response strategies on the transmission system. More specifically, GridLAB-D, a distribution system tool, and PowerWorld, a transmission planning tool, are integrated into a single simulation environment. The integrated environment allows the load flow interactions between the bulk power system and end-use loads to be explicitly modeled. Power system interactions are modeled down to time intervals as short as 1-second. Another practical issue is that the size and complexity of typical distribution systems makes direct integration with transmission models computationally intractable. Hence, the focus of the next main task is to develop reduced-order controllable models for some of the smart grid assets. In particular, HVAC units, which are a type of Thermostatically Controlled Loads (TCLs), are considered. The reduced-order modeling approach can be extended to other smart grid assets, like water heaters, PVs and PHEVs. Closed-loop control strategies are designed for a population of HVAC units under realistic conditions. The proposed load controller is fully responsive and achieves the control objective without sacrificing the end-use performance. Finally, using the T&D simulation platform, the benefits to the bulk power system are demonstrated by controlling smart grid assets under different demand response closed-loop control strategies.

  20. Effect of grain on silage characteristics for ruminants 

    E-Print Network [OSTI]

    Groves, William Grady

    1977-01-01

    F 'C'1' QZ GRAI!i OU SILAG" CHA~ACZ ';. ISTIC', ~OR RU1'IliuA1TS A ihesis by '. vl' 1. IA11 GRADY GROV~ S Sub. ~i ted to the Graduate Colle'e of Texas A~~", Univsrsity in partial fulfill:nant of the re", .ui anent for the de~res of , EST...:. . . OZ SCI=11C=- ilay " '&77 i. ajor' Su'ojac: Ani:nal 1ut rition =FFECI' OF GRAIN ON SILAG ~ CNARACT 'RIG TICS FOR PUIIINANTS A Thesis by ". /ILLIAi'I GRADY GROVES Approved as to style and content by: airman of Coi-. . sittee H a ~ Dep rti...