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Note: This page contains sample records for the topic "vapor-phase diffusion mechanisms" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
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1

Vapor phase modifiers for oxidative coupling  

DOE Patents [OSTI]

Volatilized metal compounds retard vapor phase alkane conversion reactions in oxidative coupling processes that convert lower alkanes to higher hydrocarbons.

Warren, Barbara K. (Charleston, WV)

1991-01-01T23:59:59.000Z

2

Vapor phase modifiers for oxidative coupling  

DOE Patents [OSTI]

Volatilized metal compounds are described which are capable of retarding vapor phase alkane conversion reactions in oxidative coupling processes that convert lower alkanes to higher hydrocarbons.

Warren, B.K.

1991-12-17T23:59:59.000Z

3

Vapor phase transport at a hillside landfill  

Science Journals Connector (OSTI)

...ambient density gradients. Post-landfill gas input reverses the direction of...landfill may explain observations of landfill gas found at depth. Post-landfill...of gas generation. Transport of landfill gas is shown to be dominated by diffusion...

P. H. Stauffer; N. D. Rosenberg

4

Preliminary assessment of halogenated alkanes as vapor-phase tracers  

SciTech Connect (OSTI)

New tracers are needed to evaluate the efficiency of injection strategies in vapor-dominated environments. One group of compounds that seems to meet the requirements for vapor-phase tracing are the halogenated alkanes (HCFCs). HCFCs are generally nontoxic, and extrapolation of tabulated thermodynamic data indicate that they will be thermally stable and nonreactive in a geothermal environment. The solubilities and stabilities of these compounds, which form several homologous series, vary according to the substituent ratios of fluorine, chlorine, and hydrogen. Laboratory and field tests that will further define the suitability of HCFCs as vapor-phase tracers are under way.

Adams, Michael C.; Moore, Joseph N.; Hirtz, Paul

1991-01-01T23:59:59.000Z

5

The influence of prestrained metalorganic vapor phase epitaxial gallium-nitride templates on hydride vapor phase epitaxial growth  

Science Journals Connector (OSTI)

We have varied the strain situation in metalorganic vapor phase epitaxial (MOVPE) grown gallium-nitride (GaN) by exchanging the nucleation layer and by inserting a submono-Si x N y -interlayer in the first few hundred nanometers of growth on sapphire substrates. The influence on the MOVPE template and subsequent hydride vapor phase epitaxial (HVPE) growth could be shown by in-situ measurements of the sample curvature. Using the results of these investigations we have established a procedure to confine the curvature development in MOVPE and HVPE growth to a minimum. By increasing the layer thickness in HVPE we could create self-separated freestanding GaN layers with small remaining curvature.

2014-01-01T23:59:59.000Z

6

Growth of manganese filled carbon nanofibers in the vapor phase  

Science Journals Connector (OSTI)

We report the vapor phase growth of partially filled graphitic fibers, 20-30 nm in diameter and up to a micron in length, during a manganese catalyzed carbon electric arc discharge. The fiber morphology resembles that of catalytic chemical vapor deposited carbon filaments but the inside hollow contains intermittent precipitates and continuous filling of Mn that at times occupy >50% of fiber lengths. Transmission electron microscopy and electron energy loss line spectra show that the fillings form as solid cores and may correspond to pure metal.

P. M. Ajayan; C. Colliex; J. M. Lambert; P. Bernier; L. Barbedette; M. Tence; O. Stephan

1994-03-14T23:59:59.000Z

7

Characterization of isothermal vapor phase epitaxial (Hg,Cd)Te  

Science Journals Connector (OSTI)

We report on the characterization of mercury cadmium telluride (Hg 1?x Cd x Te) film grown by the isothermal vapor phase epitaxial method (ISOVPE) and on the surface conversion of bulk Hg 1?xCd x Te to larger bandgap material. The crystal perfection is evaluated using defect etching electron beam and electrolyte electroreflectance (EBER and EER) and Rutherford backscattering spectrometry (RBS). Hall measurements are used to measure carrier densities and mobilities. Surface concentrations and concentration profiles are measured for the ISOVPE grown layers by transmission Fourier transform infrared spectroscopy (FTIR) and electron?probe microanalysis (EPMA) to establish quantitative informations about composition control. Metal–insulator?semiconductor (MIS) structures were made and the properties important to device performance such as compositional uniformity storage time and carrier concentration are measured. The ISOVPE layers are compared in quality to films grown by other methods and show promise for MIS devices.

S. B. Lee; L. K. Magel; M. F. S. Tang; D. A. Stevenson; J. H. Tregilgas; M. W. Goodwin; R. L. Strong

1990-01-01T23:59:59.000Z

8

Vapor phase elemental sulfur amendment for sequestering mercury in contaminated soil  

DOE Patents [OSTI]

The process of treating elemental mercury within the soil is provided by introducing into the soil a heated vapor phase of elemental sulfur. As the vapor phase of elemental sulfur cools, sulfur is precipitated within the soil and then reacts with any elemental mercury thereby producing a reaction product that is less hazardous than elemental mercury.

Looney, Brian B.; Denham, Miles E.; Jackson, Dennis G.

2014-07-08T23:59:59.000Z

9

DIFFUSION MECHANISMS FOR MULTIMEDIA BROADCASTING IN MOBILE AD HOC NETWORKS  

E-Print Network [OSTI]

DIFFUSION MECHANISMS FOR MULTIMEDIA BROADCASTING IN MOBILE AD HOC NETWORKS E. Baccelli Hitachi HSAL: Philippe.Jacquet@inria.fr ABSTRACT Scarce bandwidth and interferences in mobile ad-hoc networks yield in view to gain enough performance and allow applications such as multimedia diffusion in an ad hoc

Paris-Sud XI, Université de

10

Aluminum Nitride Micro-Channels Grown via Metal Organic Vapor Phase Epitaxy for MEMs Applications  

SciTech Connect (OSTI)

Aluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nanoelectromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro-channels for fuel cell applications, and micromechanical resonators. This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ìm to 110 ìm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.

Rodak, L.E.; Kuchibhatla, S.; Famouri, P.; Ting, L.; Korakakis, D.

2008-01-01T23:59:59.000Z

11

Sulfur Impregnation on Activated Carbon Fibers through H2S Oxidation for Vapor Phase  

E-Print Network [OSTI]

Sulfur Impregnation on Activated Carbon Fibers through H2S Oxidation for Vapor Phase Mercury: Sulfur was impregnated onto activated carbon fibers ACFs through H2S oxidation catalyzed by the sorbent CE Database subject headings: Activated carbon; Sulfur; Mercury; Hydrogen sulfides; Oxidation

Borguet, Eric

12

Sulfurization of a carbon surface for vapor phase mercury removal II: Sulfur forms and mercury uptake  

E-Print Network [OSTI]

promote the formation of organic sulfur and the presence of H2S during the cooling process increased in the presence of H2S was very effective towards Hg uptake in nitrogen. Corre- lation of mercury uptake capacitySulfurization of a carbon surface for vapor phase mercury removal ­ II: Sulfur forms and mercury

Borguet, Eric

13

Substrate effect on CdTe layers grown by metalorganic vapor phase N. V. Sochinskiia),b)  

E-Print Network [OSTI]

Substrate effect on CdTe layers grown by metalorganic vapor phase epitaxy N. V. Sochinskiia for publication 30 December 1996 CdTe layers were grown by metalorganic vapor phase epitaxy MOVPE on different substrates like sapphire, GaAs, and CdTe wafers. The growth was carried out at the temperature 340 °C

Viña, Luis

14

In situ, subsurface monitoring of vapor-phase TCE using fiber optics  

SciTech Connect (OSTI)

A vapor-phase, reagent-based, fiber optic trichloroethylene (TCE) sensor developed by Lawrence Livermore National Laboratory (LLNL) was demonstrated at the Savannah River Site (SRS) in two configurations. The first incorporated the sensor into a down-well instrument bounded by two inflatable packers capable of sealing an area for discrete depth analysis. The second involved an integration of the sensor into the probe tip of the Army Corps of Engineers Waterways Experiment Station (WES) cone penetrometry system. Discrete depth measurements of vapor-phase concentrations of TCE in the vadose zone were successfully made using both configurations. These measurements demonstrate the first successful in situ sensing (as opposed to sampling) of TCE at a field site.

Rossabi, J. [Westinghouse Savannah River Co., Aiken, SC (United States); Colston, B. Jr.; Brown, S.; Milanovich, F. [Lawrence Livermore National Lab., CA (United States); Lee, L.T. Jr. [Army Engineer Waterways Experiment Station, Vicksburg, MS (United States). Geotechnical Lab.

1993-03-05T23:59:59.000Z

15

Microsoft Word - Vapor Phase Elemental Sulfur Tech Brief DRAFT bbl 08-24.docx  

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

AT A GLANCE AT A GLANCE  eliminates excavation expense  applicable to large or small sites  straightforward deployment  uses heat to distribute sulfur throughout a soil  mercury reacts with sulfur to form immobile and insoluble minerals  patent applied for TechBrief Vapor Phase Elemental Sulfur Amendment for Sequestering Mercury in Contaminated Soil Scientists at the Savannah River National Laboratory (SRNL) have identified a method of targeting mercury in contaminated soil zone by use of sulfur vapor heated gas. Background Mercury contamination in soil is a common problem in the environment. The most common treatment is excavation - a method that works well for small sites where the

16

A description of the vapor phase in the lithium thionyl chloride battery  

E-Print Network [OSTI]

A DESCRIPTION OF TIIE YAPOP, PHASE IN THF. LITHIUM THIONYI. CHLORIDE BATTERY A Thesis by RODOLFO MORALES, JR. Submitted to the Graduate College of Texas AEzM University in partial fulfrHment of the requirement for the degree oi' MASTER... OF SCIENCE August 1988 Major Subject: Chemical Engineering A DESCRIPTION OF THE VAPOR PHASE IN THE LITHIUM THIONYL CHLORIDE BATTERY A Thesis bv RODOLFO 'vIORALES, JR. Approved as to style and content by: Ralph E. White (Chairman of Committee) James...

Morales, Rodolfo

1988-01-01T23:59:59.000Z

17

Lithium diffusion mechanisms in layered intercalation compounds A. Van der Ven*  

E-Print Network [OSTI]

Lithium diffusion mechanisms in layered intercalation compounds A. Van der Ven* , G. Ceder; accepted 28 December 2000 Abstract We investigate the mechanisms of lithium diffusion in layered intercalation compounds from ®rst-principles. We focus on LixCoO2 and ®nd that lithium diffusion

Ceder, Gerbrand

18

Growth of vertical-cavity surface emitting lasers by metalorganic vapor phase epitaxy  

SciTech Connect (OSTI)

We present growth and characterization of visible and near-infrared vertical-cavity surface emitting lasers (VCSELs) grown by metalorganic vapor phase epitaxy. Discussions on the growth issue of VCSEL materials include growth rate and composition control using an {ital in}{ital situ} normal-incidence reflectometer, comprehensive p- and n-type doping study in AlGaAs by CCl{sub 4} and Si{sub 2}H{sub 6} over the entire composition range, and optimization of ultra-high material uniformity. We also demonstrate our recent achievements of all-AlGaAs VCSELs which include the first room-temperature continuous- wave demonstration of 700-nm red VCSELs and high-efficiency and low- threshold voltage 850-nm VCSELs.

Hou, H.Q.; Hammons, B.E.; Crawford, M.H.; Lear, K.L.; Choquette, K.D.

1996-10-01T23:59:59.000Z

19

FeP precipitates in hydride?vapor phase epitaxially grown InP:Fe  

Science Journals Connector (OSTI)

Fe?doped InP was grown by hydride?vapor phase epitaxy.Doping levels up to 8×1018 cm?3 were determined by secondary ion mass spectrometry. Additionally performed photoluminescence measurements revealed a homogeneous distribution of electrically active Fe atoms. From microstructural investigations by analytical transmission electron microscopy spherical?shaped precipitates were detected in plan?view samples. These precipitates with diameters up to 13 nm are homogeneously arranged in the epilayer. For conglomerates of precipitates a distinct enrichment with Fe and P was measured by a comparative energy dispersive x?ray analysis. The lattice plane distances of the precipitates were deduced from the electron diffraction patterns and from high?resolution electron micrographs. A comparison with calculated values for different Fe–P alloys indicates that the precipitates consist mainly of orthorhombic FeP.

M. Luysberg; R. Göbel; H. Janning

1994-01-01T23:59:59.000Z

20

Hydride vapor phase epitaxy and characterization of high-quality ScN epilayers  

SciTech Connect (OSTI)

The heteroepitaxial growth of ScN films was investigated on various substrates by hydride vapor phase epitaxy (HVPE). Single crystalline mirror-like ScN(100) and ScN(110) layers were successfully deposited on r- and m-plane sapphire substrates, respectively. Homogeneous stoichiometric films (N/Sc ratio 1.01?±?0.10) up to 40??m in thickness were deposited. Their mosaicity drastically improved with increasing the film thickness. The band gap was determined by optical methods to be 2.06?eV. Impurity concentrations including H, C, O, Si, and Cl were investigated through energy dispersive X-ray spectrometry and secondary ion mass spectrometry. As a result, it was found that the presence of impurities was efficiently suppressed in comparison with that of HVPE-grown ScN films reported in the past, which was possible thanks to the home-designed corrosion-free HVPE reactor. Room-temperature Hall measurements indicated that the residual free electron concentrations ranged between 10{sup 18}–10{sup 20}?cm{sup ?3}, which was markedly lower than the reported values. The carrier mobility increased monotonically with the decreasing in carrier concentration, achieving the largest value ever reported, 284?cm{sup 2}?V{sup ?1}?s{sup ?1} at n?=?3.7?×?10{sup 18}?cm{sup ?3}.

Oshima, Yuichi, E-mail: OSHIMA.Yuichi@nims.go.jp; Víllora, Encarnación G.; Shimamura, Kiyoshi [Environment and Energy Materials Research Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

2014-04-21T23:59:59.000Z

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


21

Shale-Gas Permeability and Diffusivity Inferred by Improved Formulation of Relevant Retention and Transport Mechanisms  

Science Journals Connector (OSTI)

A theoretically improved model incorporating the relevant mechanisms of gas retention and transport in gas-bearing shale formations is presented for determination of intrinsic gas permeability and diffusivity. Th...

Faruk Civan; Chandra S. Rai; Carl H. Sondergeld

2011-02-01T23:59:59.000Z

22

Recent progress in GaInAsSb thermophotovoltaics grown by organometallic vapor phase epitaxy  

SciTech Connect (OSTI)

Studies on the materials development of Ga{sub 1{minus}x}In{sub x}As{sub y}Sb{sub 1{minus}y} alloys for thermophotovoltaic (TPV) devices are reviewed. Ga{sub 1{minus}x}In{sub x}As{sub y}Sb{sub 1{minus}y} epilayers were grown lattice matched to GaSb substrates by organometallic vapor phase epitaxy (OMVPE) using all organometallic precursors including triethylgallium, trimethylindium, tertiarybutylarsine, and trimethylantimony with diethyltellurium and dimethylzinc as the n- and p-type dopants, respectively. The overall material quality of these alloys depends on growth temperature, In content, V/III ratio, substrate misorientation, and to a lesser extent, growth rate. A mirror-like surface morphology and room temperature photoluminescence (PL) are obtained for GaInAsSb layers with peak emission in the wavelength range between 2 and 2.5 {micro}m. The crystal quality improves for growth temperature decreasing from 575 to 525 C, and with decreasing In content, as based on epilayer surface morphology and low temperature PL spectra. A trend of smaller full width at half-maximum for low temperature PL spectra is observed as the growth rate is increased from 1.5 to 2.5 and 5 {micro}m/h. In general, GaInAsSb layers grown on (100) GaSb substrates with a 6{degree} toward (111)B misorientation exhibited overall better material quality than layers grown on the more standard substrate (100)2{degree} toward (110). Consistent growth of high performance lattice-matched GaInAsSb TPV devices is also demonstrated.

Wang, C.A.; Choi, H.K.; Oakley, D.C. [Massachusetts Inst. of Tech., Lexington, MA (United States). Lincoln Lab.; Charache, G.W. [Lockheed Martin, Inc., Schenectady, NY (United States)

1998-06-01T23:59:59.000Z

23

Identification of vapor-phase chemical warfare agent simulants and rocket fuels using laser-induced breakdown spectroscopy  

SciTech Connect (OSTI)

Application of laser-induced breakdown spectroscopy (LIBS) to the identification of security threats is a growing area of research. This work presents LIBS spectra of vapor-phase chemical warfare agent simulants and typical rocket fuels. A large dataset of spectra was acquired using a variety of gas mixtures and background pressures and processed using partial least squares analysis. The five compounds studied were identified with a 99% success rate by the best method. The temporal behavior of the emission lines as a function of chamber pressure and gas mixture was also investigated, revealing some interesting trends that merit further study.

Stearns, Jaime A.; McElman, Sarah E.; Dodd, James A.

2010-05-01T23:59:59.000Z

24

Treatment of Produced Waters Using a Surfactant Modified Zeolite/Vapor Phase Bioreactor System  

SciTech Connect (OSTI)

This report summarizes work performed on this project from October 2004 through March 2005. In previous work, a surfactant modified zeolite (SMZ) was shown to be an effective system for removing BTEX contaminants from produced water. Additional work on this project demonstrated that a compost-based biofilter could biodegrade the BTEX contaminants found in the SMZ regeneration waste gas stream. However, it was also determined that the BTEX concentrations in the waste gas stream varied significantly during the regeneration period and the initial BTEX concentrations were too high for the biofilter to handle effectively. A series of experiments were conducted to determine the feasibility of using a passive adsorption column placed upstream of the biofilter to attenuate the peak gas-phase VOC concentrations delivered to the biofilter during the SMZ regeneration process. In preparation for the field test of the SMZ/VPB treatment system in New Mexico, a pilot-scale SMZ system was also designed and constructed during this reporting period. Finally, a cost and feasibility analysis was also completed. To investigate the merits of the passive buffering system during SMZ regeneration, two adsorbents, SMZ and granular activated carbon (GAC) were investigated in flow-through laboratory-scale columns to determine their capacity to handle steady and unsteady VOC feed conditions. When subjected to a toluene-contaminated air stream, the column containing SMZ reduced the peak inlet 1000 ppmv toluene concentration to 630 ppmv at a 10 second contact time. This level of buffering was insufficient to ensure complete removal in the downstream biofilter and the contact time was longer than desired. For this reason, using SMZ as a passive buffering system for the gas phase contaminants was not pursued further. In contrast to the SMZ results, GAC was found to be an effective adsorbent to handle the peak contaminant concentrations that occur early during the SMZ regeneration process. At a one second residence time, the GAC bed reduced peak contaminant concentrations by 97%. After the initial peak, the inlet VOC concentration in the SMZ regeneration gas stream drops exponentially with time. During this period, the contaminants on the GAC subsequently desorbed at a nearly steady rate over the next 45 hours resulting in a relatively steady effluent concentration of approximately 25 ppm{sub v}. This lower concentration is readily degradable by a downstream vapor phase biofilter (VPB) and the steady nature of the feed stream will prevent the biomass in the VPB from enduring starvation conditions between SMZ regeneration cycles. Repetitive sorption and desorption cycles that would be expected in the field were also investigated. It was determined that although the GAC initially lost some VOC sorption capacity, the adsorption and desorption profiles stabilized after approximately 6 cycles indicating that a GAC bed should be suitable for continuous operation. In preparation for the pilot field testing of the SMZ/VPB system, design, ''in-house'' construction and testing of the field system were completed during this project period. The design of the SMZ system for the pilot test was based on previous investigations by the PI's in Wyoming, 2002 and on analyses of the produced water at the field site in New Mexico. The field tests are scheduled for summer, 2005. A cost survey, feasibility of application and cost analyses were completed to investigate the long term effectiveness of the SMZ/VPB system as a method of treating produced water for re-use. Several factors were investigated, including: current costs to treat and dispose of produced water, end-use water quality requirements, and state and federal permitting requirements.

Soondong Kwon; Elaine B. Darby; Li-Jung Chen; Lynn E. Katz; Kerry A. Kinney; R. S. Bowman; E. J. Sullivan

2005-03-11T23:59:59.000Z

25

Efficient diffusive mechanisms of O atoms at very low temperatures on surfaces of astrophysical interest  

E-Print Network [OSTI]

At the low temperatures of interstellar dust grains, it is well established that surface chemistry proceeds via diffusive mechanisms of H atoms weakly bound (physisorbed) to the surface. Until recently, however, it was unknown whether atoms heavier than hydrogen could diffuse rapidly enough on interstellar grains to react with other accreted species. In addition, models still require simple reduction as well as oxidation reactions to occur on grains to explain the abundances of various molecules. In this paper we investigate O-atom diffusion and reactivity on a variety of astrophysically relevant surfaces (water ice of three different morphologies, silicate, and graphite) in the 6.5 - 25 K temperature range. Experimental values were used to derive a diffusion law that emphasizes that O atoms diffuse by quantum mechanical tunnelling at temperatures as low as 6.5 K. The rate of diffusion on each surface, based on modelling results, were calculated and an empirical law is given as a function of the surface tempe...

Congiu, E; Baouche, S; Chaabouni, H; Moudens, A; Cazaux, S; Manicò, G; Pirronello, V; Dulieu, F

2014-01-01T23:59:59.000Z

26

Effect of atomic scale plasticity on hydrogen diffusion in iron: Quantum mechanically informed and on-the-fly kinetic  

E-Print Network [OSTI]

viewpoints, is futile. Among several mechanisms proposed for hydrogen embrittlement (HE) of metals, hydrogenEffect of atomic scale plasticity on hydrogen diffusion in iron: Quantum mechanically informed-assisted diffusion and trapping of hydrogen by crystalline defects in iron. Given an embedded atom (EAM) potential

Ortiz, Michael

27

Time-resolved photoluminescence, positron annihilation, and Al0.23Ga0.77N/GaN heterostructure growth studies on low defect density polar and nonpolar freestanding GaN substrates grown by hydride vapor phase epitaxy  

Science Journals Connector (OSTI)

Time-resolved photoluminescence(TRPL) and positron annihilation measurements as well as Al0.23Ga0.77N/GaN heterostructuregrowth by metalorganic vapor phase epitaxy were carried out on very low defect density polar c-plane and nonpolar m-plane freestanding GaN (FS-GaN) substrates grown by hydride vapor phase epitaxy. Room-temperature photoluminescence(PL) lifetime for the near-band-edge (NBE) excitonic emission of the FS-GaN substrates increases with increasing positron diffusion length (L +); i.e. decreasing gross concentration of charged and neutral point defects and complexes. The best undoped c-plane FS-GaN exhibits record-long L + being 116?nm. The fast component of the PL lifetime for its NBE emission increases with temperature rise up to 100?K and levels off at approximately 1.1?ns. The result implies a saturation in thermal activation of nonradiative recombination centers. The surface and interface roughnesses for a Si-doped Al0.23Ga0.77N/GaN/Al0.18Ga0.82N/GaN heterostructure are improved by the use of FS-GaN substrates in comparison with the structure fabricated on a standard GaN template. The emission signals related to the recombination of a two-dimensional electron gas and excited holes are recognized for an Al0.23Ga0.77N/GaN single heterostructuregrown on the c-plane FS-GaN substrate.

S. F. Chichibu; K. Hazu; Y. Ishikawa; M. Tashiro; H. Namita; S. Nagao; K. Fujito; A. Uedono

2012-01-01T23:59:59.000Z

28

Atomic-scale diffusion mechanisms via intermediate species Ant Ural,* P. B. Griffin, and J. D. Plummer  

E-Print Network [OSTI]

available isotopically enriched Si structures yielded the values of the transport capacities of I and V.4 evidence for the intermediate diffusion mechanism of boron in silicon has been obtained at short diffusion an intermediate species determines the overall migration of an impurity. First, we present a general formu- lation

Ural, Ant

29

Controlled Vapor Phase Growth of Single Crystalline, Two-Dimensional GaSe Crystals with High Photoresponse  

SciTech Connect (OSTI)

Abstract Compared with their bulk counterparts, atomically thin two-dimensional (2D) crystals exhibit new physical properties, and have the potential to enable next-generation electronic and optoelectronic devices. However, controlled synthesis of large uniform monolayer and multi-layer 2D crystals is still challenging. Here, we report the controlled synthesis of 2D GaSe crystals on SiO2/Si substrates using a vapor phase deposition method. For the first time, uniform, large (up to ~60 m in lateral size), single-crystalline, triangular monolayer GaSe crystals were obtained and their atomic resolution structure were characterized. The size, density, shape, thickness, and uniformity of the 2D GaSe crystals were shown to be controllable by growth duration, growth region, growth temperature, and argon carrier gas flow rate. The theoretical modeling of the electronic structure and Raman spectroscopy demonstrate a direct-to-indirect bandgap transition and progressive confinement-induced bandgap shifts for 2D GaSe crystals. The 2D GaSe crystals show p-type semiconductor characteristics and high photoresponsivity (~1.7 A/W under white light illumination) comparable to exfoliated GaSe nanosheets. These 2D GaSe crystals are potentially useful for next-generation electronic and optoelectronic devices such as photodetectors and field-effect transistors.

Li, Xufan [ORNL; Lin, Ming-Wei [ORNL; Zhang, Huidong [University of Tennessee, Knoxville (UTK); Puretzky, Alexander A [ORNL; Idrobo Tapia, Juan C [ORNL; Ma, Cheng [ORNL; Chi, Miaofang [ORNL; Yoon, Mina [ORNL; Rouleau, Christopher M [ORNL; Kravchenko, Ivan I [ORNL; Geohegan, David B [ORNL; Xiao, Kai [ORNL

2014-01-01T23:59:59.000Z

30

Verification of the integrity of barriers using gas diffusion  

SciTech Connect (OSTI)

In-situ barrier materials and designs are being developed for containment of high risk contamination as an alternative to immediate removal or remediation. The intent of these designs is to prevent the movement of contaminants in either the liquid or vapor phase by long-term containment, essentially buying time until the contaminant depletes naturally or a remediation can be implemented. The integrity of the resultant soil-binder mixture is typically assessed by a number of destructive laboratory tests (leaching, compressive strength, mechanical stability with respect to wetting and freeze-thaw cycles) which as a group are used to infer the likelihood of favorable long-term performance of the barrier. The need exists for a minimally intrusive yet quantifiable methods for assessment of a barrier`s integrity after emplacement, and monitoring of the barrier`s performance over its lifetime. Here, the authors evaluate non-destructive measurements of inert-gas diffusion (specifically, SF{sub 6}) as an indicator of waste-form integrity. The goals of this project are to show that diffusivity can be measured in core samples of soil jet-grouted with Portland cement, validate the experimental method through measurements on samples, and to calculate aqueous diffusivities from a series of diffusion measurements. This study shows that it is practical to measure SF{sub 6} diffusion rates in the laboratory on samples of grout (Portland cement and soil) typical of what might be used in a barrier. Diffusion of SF{sub 6} through grout (Portland cement and soil) is at least an order of magnitude slower than through air. The use of this tracer should be sensitive to the presence of fractures, voids, or other discontinuities in the grout/soil structure. Field-scale measurements should be practical on time-scales of a few days.

Ward, D.B. [SPECTRA Research Inst., Albuquerque, NM (United States); Williams, C.V. [Sandia National Labs., Albuquerque, NM (United States). Environmental Restoration Technologies Dept.

1997-06-01T23:59:59.000Z

31

Proton diffusion pathways and rates in Y-doped BaZrO3 solid oxide electrolyte from quantum mechanics  

E-Print Network [OSTI]

solid oxide fuel cells based on yttria-stabilized zirconia. In addition, doped perovskite oxides oftenProton diffusion pathways and rates in Y-doped BaZrO3 solid oxide electrolyte from quantum solid oxide proton conductors the principal fea- tures of the proton transport mechanism are generally

Goddard III, William A.

32

X-ray determination of threading dislocation densities in GaN/Al{sub 2}O{sub 3}(0001) films grown by metalorganic vapor phase epitaxy  

SciTech Connect (OSTI)

Densities of a- and a+c-type threading dislocations for a series of GaN films grown in different modes by metalorganic vapor phase epitaxy are determined from the x-ray diffraction profiles in skew geometry. The reciprocal space maps are also studied. Theory of x-ray scattering from crystals with dislocations is extended in order to take into account contribution from both threading and misfit dislocations. The broadening of the reciprocal space maps along the surface normal and the rotation of the intensity distribution ellipse is attributed to misfit dislocations at the interface. We find that the presence of a sharp AlN/GaN interface leads to an ordering of misfit dislocations and reduces strain inhomogeneity in GaN films.

Kopp, Viktor S., E-mail: victor.kopp@pdi-berlin.de; Kaganer, Vladimir M. [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5–7, 10117 Berlin (Germany); Baidakova, Marina V.; Lundin, Wsevolod V.; Nikolaev, Andrey E.; Verkhovtceva, Elena V.; Yagovkina, Maria A. [Ioffe Physical-Technical Institute of the Russian Academy of Sciences, Politekhnicheskaya 26, 194021 St.-Petersburg (Russian Federation); Cherkashin, Nikolay [CEMES-CNRS and Université de Toulouse, 29 rue J. Marvig, 31055 Toulouse (France)

2014-02-21T23:59:59.000Z

33

Study of the nitrogen diffusion mechanism in R2Fe17 Y. D. Zhang, J. I. Budnick, and W. A. Hines  

E-Print Network [OSTI]

Study of the nitrogen diffusion mechanism in R2Fe17 Y. D. Zhang, J. I. Budnick, and W. A. Hines 06269 D. P. Yang Department of Physics, College of the Holy Cross, Worcester, Massachusetts 01610

Yang, De-Ping

34

Mechanism model for shale gas transport considering diffusion, adsorption/desorption and Darcy flow  

Science Journals Connector (OSTI)

To improve the understanding of the transport mechanism in shale gas reservoirs and build a theoretical basic for ... on productivity evaluation and efficient exploitation, various gas transport mechanisms within...

Ming-qiang Wei ???; Yong-gang Duan ???…

2013-07-01T23:59:59.000Z

35

Microstructure and mechanical properties of diffusion bonded W/steel joint using V/Ni composite interlayer  

SciTech Connect (OSTI)

Diffusion bonding between W and steel using V/Ni composite interlayer was carried out in vacuum at 1050 °C and 10 MPa for 1 h. The microstructural examination and mechanical property evaluation of the joints show that the bonding of W to steel was successful. No intermetallic compound was observed at the steel/Ni and V/W interfaces for the joints bonded. The electron probe microanalysis and X-ray diffraction analysis revealed that Ni{sub 3}V, Ni{sub 2}V, Ni{sub 2}V{sub 3} and NiV{sub 3} were formed at the Ni/V interface. The tensile strength of about 362 MPa was obtained for as-bonded W/steel joint and the failure occurred at W near the V/W interface. The nano-indentation test across the joining interfaces demonstrated the effect of solid solution strengthening and intermetallic compound formation in the diffusion zone. - Highlights: • Diffusion bonding of W to steel was realized using V/Ni composite interlayer. • The interfacial microstructure of the joint was clarified. • Several V–Ni intermetallic compounds were formed in the interface region. • The application of V/Ni composite interlayer improved the joining quality.

Liu, W.S.; Cai, Q.S., E-mail: cai2009pm@163.com; Ma, Y.Z.; Wang, Y.Y.; Liu, H.Y.; Li, D.X.

2013-12-15T23:59:59.000Z

36

Organometallic Vapor Phase Epitaxy of n-GaSb and n-GaInAsSb for Low Resistance Ohmic Contacts  

SciTech Connect (OSTI)

A comparison of n-GaSb and n-GaInAsSb epilayers for ohmic contacts in GaSb-based devices is studied. The epilayers were grown by organometallic vapor phase epitaxy and doped with Te. At similar electron concentrations, the atomic Te concentration, as determined by secondary ion mass spectroscopy, is more than 2 times higher in n-GaSb compared to n-GaInAsSb. In addition, the electron mobility is lower in n-GaSb than n-GaInAsSb at similar electron concentrations. The electron concentration saturates at about 1.3 x 10{sup 18} cm{sup -3} for n-GaSb, but linearly increases for n-GaInAsSb. Pd/Ge/Au/Pt/Au metallization was studied for ohmic contacts. A specific contact resistivity of 1 x 10{sup -5}{Omega}-cm{sup 2} for n-GaSb was measured. The specific contact resistivity can be greatly improved by contacting n-GaInAsSb, and a significantly lower specific contact resistivity of 2 x 10{sup -6} {Omega}-cm{sup 2} for n-GaInAsSb was measured.

C.A. Wang; D.A. Shiau; R.K. Huang; C.T. Harris; M.K. Connors

2003-07-10T23:59:59.000Z

37

Long Term Field Development of a Surfactant Modified Zeolite/Vapor Phase Bioreactor System for Treatment of Produced Waters for Power Generation  

SciTech Connect (OSTI)

The main goal of this research was to investigate the feasibility of using a combined physicochemical/biological treatment system to remove the organic constituents present in saline produced water. In order to meet this objective, a physical/chemical adsorption process was developed and two separate biological treatment techniques were investigated. Two previous research projects focused on the development of the surfactant modified zeolite adsorption process (DE-AC26-99BC15221) and development of a vapor phase biofilter (VPB) to treat the regeneration off-gas from the surfactant modified zeolite (SMZ) adsorption system (DE-FC26-02NT15461). In this research, the SMZ/VPB was modified to more effectively attenuate peak loads and to maintain stable biodegradation of the BTEX constituents from the produced water. Specifically, a load equalization system was incorporated into the regeneration flow stream. In addition, a membrane bioreactor (MBR) system was tested for its ability to simultaneously remove the aromatic hydrocarbon and carboxylate components from produced water. The specific objectives related to these efforts included the following: (1) Optimize the performance VPBs treating the transient loading expected during SMZ regeneration: (a) Evaluate the impact of biofilter operating parameters on process performance under stable operating conditions. (b) Investigate how transient loads affect biofilter performance, and identify an appropriate technology to improve biological treatment performance during the transient regeneration period of an SMZ adsorption system. (c) Examine the merits of a load equalization technology to attenuate peak VOC loads prior to a VPB system. (d) Evaluate the capability of an SMZ/VPB to remove BTEX from produced water in a field trial. (2) Investigate the feasibility of MBR treatment of produced water: (a) Evaluate the biodegradation of carboxylates and BTEX constituents from synthetic produced water in a laboratory-scale MBR. (b) Evaluate the capability of an SMZ/MBR system to remove carboxylates and BTEX from produced water in a field trial. Laboratory experiments were conducted to provide a better understanding of each component of the SMZ/VPB and SMZ/MBR process. Laboratory VPB studies were designed to address the issue of influent variability and periodic operation (see DE-FC26-02NT15461). These experiments examined multiple influent loading cycles and variable concentration loadings that simulate air sparging as the regeneration option for the SMZ system. Two pilot studies were conducted at a produced water processing facility near Farmington, New Mexico. The first field test evaluated SMZ adsorption, SMZ regeneration, VPB buffering, and VPB performance, and the second test focused on MBR and SMZ/MBR operation. The design of the field studies were based on the results from the previous field tests and laboratory studies. Both of the biological treatment systems were capable of removing the BTEX constituents in the laboratory and in the field over a range of operating conditions. For the VPB, separation of the BTEX constituents from the saline aqueous phase yielded high removal efficiencies. However, carboxylates remained in the aqueous phase and were not removed in the combined VPB/SMZ system. In contrast, the MBR was capable of directly treating the saline produced water and simultaneously removing the BTEX and carboxylate constituents. The major limitation of the MBR system is the potential for membrane fouling, particularly when the system is treating produced water under field conditions. The combined process was able to effectively pretreat water for reverse osmosis treatment and subsequent downstream reuse options including utilization in power generation facilities. The specific conclusions that can be drawn from this study are summarized.

Lynn Katz; Kerry Kinney; Robert Bowman; Enid Sullivan; Soondong Kwon; Elaine Darby; Li-Jung Chen; Craig Altare

2007-12-31T23:59:59.000Z

38

Understanding of interface structures and reaction mechanisms induced by Ge or GeO diffusion in Al{sub 2}O{sub 3}/Ge structure  

SciTech Connect (OSTI)

The reaction mechanisms at Al{sub 2}O{sub 3}/Ge interfaces with thermal oxidation through the Al{sub 2}O{sub 3} layer have been investigated. X-ray photoelectron spectroscopy reveals that an Al{sub 6}Ge{sub 2}O{sub 13} layer is formed near the interface, and a GeO{sub 2} layer is formed on the Al{sub 2}O{sub 3} surface, suggesting Ge or GeO diffusion from the Ge surface. It is also clarified that the Al{sub 6}Ge{sub 2}O{sub 13} layer is formed by the different mechanism with a small activation energy of 0.2 eV, compared with the GeO{sub 2} formation limited by oxygen diffusion. Formation of Al-O-Ge bonds due to the AlGeO formation could lead appropriate interface structures with high interface qualities.

Shibayama, Shigehisa [Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan) [Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); JSPS, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Kato, Kimihiko; Sakashita, Mitsuo; Takeuchi, Wakana; Taoka, Noriyuki; Nakatsuka, Osamu; Zaima, Shigeaki [Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)] [Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2013-08-19T23:59:59.000Z

39

1. Roller J. , Arellano-Jimneza J., Yu H. , Carter C.B., and Maric R., "Catalyst nanoscale assembly from the vapor phase on corrosion resistant supports",  

E-Print Network [OSTI]

and reactive spray deposition technology for low temperature solid oxide fuel cell", Journal of Thermal Spray Temperature Solid Oxide Fuel Cell (LTSOFC) by Reactive Spray Deposition Technology, RSDT, ECS Trans., 35.-P., Stöver, D., "Gas phase deposition of diffusion barriers for metal substrates in solid oxide fuel cells

Alpay, S. Pamir

40

Enhanced self-diffusion of adsorbed methanol in silica aerogel  

Science Journals Connector (OSTI)

Molecular transport of a two-component system of liquid and vapor in a porous medium can be anomalously increased owing to fast exchange between the two phases [Phys. Rev. Lett. 63, 43 (1989)]. We have investigated this phenomenon measuring the self-diffusion coefficient of methanol adsorbed in a 98% porosity aerogel using nuclear magnetic resonance field gradient techniques. We found enhancement of several orders of magnitude from which we determined the ballistic mean-free path in the vapor phase. We have grown globally uniform anisotropic aerogels and applied the diffusion measurements to characterize the anisotropy. Our results are important for understanding the novel properties of superfluid He3 confined within an aerogel framework and for application to other physical systems.

Jeongseop A. Lee; A. M. Mounce; Sangwon Oh; A. M. Zimmerman; W. P. Halperin

2014-11-03T23:59:59.000Z

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


41

Charge transport properties of p-CdTe/n-CdTe/n{sup +}-Si diode-type nuclear radiation detectors based on metalorganic vapor-phase epitaxy-grown epilayers  

SciTech Connect (OSTI)

Charge transport properties of p-CdTe/n-CdTe/n{sup +}-Si diode-type nuclear radiation detectors, fabricated by growing p-and n-type CdTe epilayers on (211) n{sup +}-Si substrates using metalorganic vapor-phase epitaxy (MOVPE), were studied by analyzing current-voltage characteristics measured at various temperatures. The diode fabricated shows good rectification properties, however, both forward and reverse biased currents deviate from their ideal behavior. The forward current exhibits typical feature of multi-step tunneling at lower biases; however, becomes space charge limited type when the bias is increased. On the other hand, the reverse current exhibits thermally activated tunneling-type current. It was found that trapping centers at the p-CdTe/n-CdTe junction, which were formed due to the growth induced defects, determine the currents of this diode, and hence limit the performance of the nuclear radiation detectors developed.

Niraula, M.; Yasuda, K.; Wajima, Y.; Yamashita, H.; Tsukamoto, Y.; Suzuki, Y.; Matsumoto, M.; Takai, N.; Tsukamoto, Y.; Agata, Y. [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555 (Japan)] [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555 (Japan)

2013-10-28T23:59:59.000Z

42

Portsmouth Gaseous Diffusion Plant | Department of Energy  

Energy Savers [EERE]

Gaseous Diffusion Plant. March 26, 2010 Enforcement Letter, Geiger Brothers Mechanical Contractors, INC - March 26, 2010 Issued to Geiger Brothers Mechanical Contractors,...

43

Enforcement Documents - Portsmouth Gaseous Diffusion Plant |...  

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

Gaseous Diffusion Plant March 26, 2010 Enforcement Letter, Geiger Brothers Mechanical Contractors, INC - March 26, 2010 Issued to Geiger Brothers Mechanical Contractors,...

44

Photoelectric and luminescence properties of GaSb-Based nanoheterostructures with a deep Al(As)Sb/InAsSb/Al(As)Sb quantum well grown by metalorganic vapor-phase epitaxy  

SciTech Connect (OSTI)

The luminescence and photoelectric properties of heterostructures with a deep Al(As)Sb/InAsSb/Al(As)Sb quantum well grown on n-GaSb substrates by metalorganic vapor-phase epitaxy are investigated. Intense superlinear luminescence and increased optical power as a function of the pump current in the photon energy range of 0.6-0.8 eV are observed at temperatures of T = 77 and 300 K. The photoelectric, current-voltage, and capacitance characteristics of these heterostructures are studied in detail. The photosensitivity is examined with photodetectors operating in the photovoltaic mode in the spectral range of 0.9-2.0 {mu}m. The sensitivity maximum at room temperature is observed at a wavelength of 1.55 {mu}m. The quantum efficiency, detectivity, and response time of the photodetectors were estimated. The quantum efficiency and detectivity at the peak of the photosensitivity spectrum are as high as {eta} = 0.6-0.7 and D{sub {lambda}max}{sup *} = (5-7) Multiplication-Sign 10{sup 10} cm Hz{sup 1/2} W{sup -1}, respectively. The photodiode response time determined as the rise time of the photoresponse pulse from 0.1 to the level 0.9 is 100-200 ps. The photodiode transmission bandwidth is 2-3 GHz. Photodetectors with a deep Al(As)Sb/InAsSb/Al(As)Sb quantum well grown on n-GaSb substrates are promising foruse in heterodyne detection systems and in information technologies.

Mikhailova, M. P.; Andreev, I. A., E-mail: igor@iropt9.ioffe.ru; Ivanov, E. V.; Konovalov, G. G.; Grebentshikova, E. A.; Yakovlev, Yu. P. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)] [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Hulicius, E.; Hospodkova, A.; Pangrac, Y. [Academy of Sciences of the Czech Republic, Institute of Physics (Czech Republic)] [Academy of Sciences of the Czech Republic, Institute of Physics (Czech Republic)

2013-08-15T23:59:59.000Z

45

Electronic parameters and interfacial properties of GaAs/AlxGa1-xAs multiquantum wells grown on (111)A GaAs by metalorganic vapor phase epitaxy  

Science Journals Connector (OSTI)

We report a comprehensive study of the optical and interfacial properties of GaAs/AlxGa1-xAs multiquantum wells grown on (111)A GaAs substrates by metalorganic vapor phase epitaxy which allowed the determination of the electronic parameters appropriate for such quantum wells. High-resolution x-ray diffractometry studies indicate an excellent crystal quality and good periodicity for the multiquantum wells and provided their structural parameters accurately. The photoreflectance spectra exhibit all the allowed and almost all the weakly allowed optical transitions between the confined hole and electron states. From an analysis of the photoreflectance spectra it is shown that the quantum well interfaces have an abruptness better than ±1 ML. Photoluminescence spectroscopy was also performed to evaluate independently the roughness of the interfaces and multiquantum well period reproducibility. For a 25-period multiquantum well structure with a well width of 55 Å, a photoluminescence linewidth of 12.5 meV, which corresponds to a combined well-width fluctuation and interface roughness of less than ±1 monolayer over the 25 periods, proves the achievement of heterointerfaces with excellent interfacial quality. From a detailed analysis of the high-order transitions observed in the photoreflectance spectra we determined key quantum well electronic parameters, such as, the heavy-hole valence-band offset Qv=0.33±0.02, the transverse GaAs heavy-hole effective mass mhh=(0.95±0.02)m0, and the light-hole effective mass mlh=0.08m0 in ?111? directions, for ?111?-oriented GaAs/AlxGa1-xAs quantum well structures.

Soohaeng Cho; A. Sanz-Hervás; A. Majerfeld; B. W. Kim

2003-07-10T23:59:59.000Z

46

A Bibliography of Vapor Phase Thermal Fragmentation  

Science Journals Connector (OSTI)

......inert gas on hexa- decane pyrolysis", Can. J. Chem. 47, 3477...General Review of Ether Pyrolysis," Chapt. 4 of "The Chemistry...Chralovsky, "Phenyl Dimethyl Silane," Coll. Czech. Chem. Commun...Tebben and M. A. Ring, "Disilane and Trisilane," Inorg. Chem......

Stanley F. Sarner

1972-02-01T23:59:59.000Z

47

A Bibliography of Vapor Phase Thermal Fragmentation  

Science Journals Connector (OSTI)

......Catalysis 7, 386 (1967). S. J. Price, "Toluene," Can. J. Chem...Green, and L. P. Hallee, "Ethylene," Oil Gas J. 65, 192 (1967...1962). M. Krech and S. J. Price, "Dimethyl Mercury," Can...1963). M. Krech and S. J. Price, "Dimethyl Cadmium," Can......

Stanley F. Sarner

1972-02-01T23:59:59.000Z

48

Mechanism of compensation of the donor impurity in the near-surface layer of gap during heat treatment in phosphorus vapors  

SciTech Connect (OSTI)

The secondary ion mass spectrometry and capacitance-voltage measurements have been used to study the mechanism of formation of the near-surface layer with a low concentration of uncompensated donors in n-GaP grown by vapor-phase epitaxy and subjected to heat treatment at different pressures of phosphorus vapors. The dependence of the thickness of the mentioned layer on the pressure of phosphorus vapors has a minimum at a pressure of (1.5 {+-} 0.5) x 10{sup 3} Pa. It is shown that at vapor pressures above the mentioned value, the interstitial P, which forms a deep electron trap, is a suitable candidate for the role of compensating acceptor. At low pressures, the probable compensating center is the P vacancy giving rise to a deep level with the energy Ec-(0.21 {+-} 0.01) eV. At 700 deg. C, the effective diffusivity of interstitial P is {approx}(3 {+-} 1) s- 10{sup -15} cm{sup 2}/s, while that of the P vacancy is {approx}(3 {+-} 1) x 10{sup -14} cm{sup 2}/s.

Krutogolov, Yu. K., E-mail: krutogolov@mail.ru [Research Institute for Materials of Electronic Engineering (Russian Federation)

2010-06-15T23:59:59.000Z

49

11136 J. Phys. Chem. 1994, 98, 11136-11142 A New Mechanism for Surface Diffusion: Motion of a Substrate-Adsorbate Complex  

E-Print Network [OSTI]

of a Substrate-Adsorbate Complex S. J. Stranick,?A. N. Parikh,*D. L. AllaraJ7$ and P. S. Weiss*J Departments for diffusion of surface adsorbates in which motion of the substrate atoms to which the adsorbates are attached results in the motion of the substrate-adsorbate complex. We show an experimental example-the motion

Parikh, Atul N.

50

Diffuse Scattering  

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

Diffuse Scattering Diffuse Scattering * Anticipatory (trick) question: If you have an x-ray or neutron detector looking at a small sample volume, which will scatter more x- rays or neutrons into the detector 1 atom 100 atoms or 1000 atoms? X-ray or neutron beam Answer: Depends! Diffuse Scattering Gene E. Ice Materials Science and Technology Division Oak Ridge National Laboratory, USA National School on Neutron and X-ray Scattering ORNL/SNS June 2011 Presentation concentrates year graduate-level course into 1 hour * Skip mathematical complexities * Expose to range of applications * Develop intuition for length scales * Talk like x-ray/neutron scattering guru - Reciprocal space - Debye Temperature - Laue monotonic - Krivoglaz defects of 1st/2nd kinds! Great for cocktail parties or impressing attractive strangers-

51

Theory of Grain Boundary Diffusion  

Science Journals Connector (OSTI)

The previously proposed dependence of the structure of grain boundaries upon the angle of disorientation of the two grains is used as a basis of a quantitative consideration of diffusion along grain boundaries and in particular of the apparent activation energies. At small angles in the dislocation range the diffusion is controlled by volume diffusion mechanism. At high angles near 45° the model of a uniform grain boundary is applicable. In the intermediate range an array of rod-like areas of distorted lattice leads to low or even negative apparent activation energies. The theory is in good agreement with experiment.

R. Smoluchowski

1952-08-01T23:59:59.000Z

52

EK424 THERMODYNAMICS AND STATISTICAL MECHANICS (Spring 2013) Thermodynamics is the study of processes (e.g., expansion of a gas, boiling of water, or diffusion  

E-Print Network [OSTI]

EK424 THERMODYNAMICS AND STATISTICAL MECHANICS (Spring 2013) Thermodynamics is the study in order to take place? We will study the thermodynamics of two types of processes: mechanical, or the chemical conversion of glucose into useful work), and a good understanding of thermodynamics is essential

Vajda, Sandor

53

EK424 THERMODYNAMICS AND STATISTICAL MECHANICS (Fall 2013) Thermodynamics is the study of processes (e.g., expansion of a gas, boiling of water, or diffusion  

E-Print Network [OSTI]

EK424 THERMODYNAMICS AND STATISTICAL MECHANICS (Fall 2013) Thermodynamics is the study in order to take place? We will study the thermodynamics of two types of processes: mechanical, or the chemical conversion of glucose into useful work), and a good understanding of thermodynamics is essential

Vajda, Sandor

54

Diffusion of Ca and Mg in Calcite  

SciTech Connect (OSTI)

The self-diffusion of Ca and the tracer diffusion of Mg in calcite have been experimentally measured using isotopic tracers of {sup 25}Mg and {sup 44}Ca. Natural single crystals of calcite were coated with a thermally-sputtered oxide thin film and then annealed in a CO{sub 2} gas at one atmosphere total pressure and temperatures from 550 to 800 C. Diffusion coefficient values were derived from the depth profiles obtained by ion microprobe analysis. The resultant activation energies for Mg tracer diffusion and Ca self-diffusion are respectively: E{sub a}(Mg) = 284 {+-} 74 kJ/mol and E{sub a}(Ca) = 271 {+-} 80 kJ/mol. For the temperature ranges in these experiments, the diffusion of Mg is faster than Ca. The results are generally consistent in magnitude with divalent cation diffusion rates obtained in previous studies and provide a means of interpreting the thermal histories of carbonate minerals, the mechanism of dolomitization, and other diffusion-controlled processes. The results indicate that cation diffusion in calcite is relatively slow and cations are the rate-limiting diffusing species for the deformation of calcite and carbonate rocks. Application of the calcite-dolomite geothermometer to metamorphic assemblages will be constrained by cation diffusion and cooling rates. The direct measurement of Mg tracer diffusion in calcite indicates that dolomitization is unlikely to be accomplished by Mg diffusion in the solid state but by a recrystallization process.

Cygan, R.T.; Fisler, D.K.

1999-02-10T23:59:59.000Z

55

Comments on Diffusion of Kr Isotopes in Solid Ar  

Science Journals Connector (OSTI)

Recently, the isotope effect for Kr diffusion in Ar was found to be f?K?0. 48. The results are consistent with a divacancy diffusion mechanism with ?K?1.

J. J. Burton

1970-10-15T23:59:59.000Z

56

Moisture Diffusion in Asphalt Binders and Fine Aggregate Mixtures  

E-Print Network [OSTI]

cost in highway maintenance and vehicle operations. One key mechanism of how moisture reaches the asphalt-aggregate interface is by its permeation or diffusion through the asphalt binder or mastic. Different techniques are available for diffusion...

Vasconcelos, Kamilla L.

2011-08-08T23:59:59.000Z

57

Copper diffusion in single-crystal ?-Zr  

Science Journals Connector (OSTI)

Tracer diffusion of Cu64 in ?-Zr single crystals has been measured in the temperature range (615-860)°C. The temperature dependences of the Cu64 diffusion coefficients in directions parallel to and perpendicular to the c axis are given by D?=0.40e-1.54 eVkT and D?=0.25e-1.60 eVkT cm2/sec, respectively. The results are discussed in terms of an interstitial diffusion mechanism.

G. M. Hood and R. J. Schultz

1975-05-15T23:59:59.000Z

58

Diffusive limit for the random Lorentz gas  

E-Print Network [OSTI]

We review some recent results concerning the derivation of the diffusion equation and the validation of Fick's law for the microscopic model given by the random Lorentz Gas. These results are achieved by using a linear kinetic equation as an intermediate level of description between our original mechanical system and the diffusion equation.

Alessia Nota

2014-10-14T23:59:59.000Z

59

Modeling Intragranular Diffusion in Low-Connectivity Granular...  

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

can produce diffusive behavior that appears as if the solute had undergone slow sorption, even in the absence of any sorption process. This mechanism may help explain some...

60

High-efficiency solar cells fabricated from direct-current magnetron sputtered n-indium tin oxide onto p-InP grown by atmospheric pressure metalorganic vapor phase epitaxy  

SciTech Connect (OSTI)

Solar cells based on dc magnetron sputtered indium tin oxide onto epitaxially grown films of p-InP have been fabricated and analyzed. The best cells had a global efficiency of 18.4% and an air mass zero (AMO) efficiency of 16.0%. The principal fabrication variable considered was the constituency of the sputtering gas and both argon/hydrogen and argon/oxygen mixtures have been used. The former cells have the higher efficiencies, are apparently stable, and exhibit almost ideal junction characteristics. The latter cells are relatively unstable and exhibit much higher ideality factors and reverse saturation current densities. The temperature dependence of the reverse saturation current indicates totally different charge transfer mechanisms in the two cases.

Li, X.; Wanlass, M.W.; Gessert, T.A.; Emery, K.A.; Coutts, T.J.

1989-05-01T23:59:59.000Z

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


61

Handbook on atmospheric diffusion  

SciTech Connect (OSTI)

Basic meteorological concepts are covered as well as plume rise, source effects, and diffusion models. Chapters are included on cooling tower plumes and urban diffusion. Suggestions are given for calculating diffusion in special situations, such as for instantaneous releases over complex terrain, over long distances, and during times when chemical reactions or dry or wet deposition are important. (PSB)

Hanna, S.R.; Briggs, G.A.; Hosker, R.P. Jr.

1982-01-01T23:59:59.000Z

62

Diffusive Accumulation of Methane Bubbles in Seabed  

E-Print Network [OSTI]

We consider seabed bearing methane bubbles. In the absence of fractures the bubbles are immovably trapped in a porous matrix by surface tension forces; therefore the dominant mechanism of transfer of gas mass becomes the diffusion of gas molecules through the liquid. The adequate description of this process requires accounting "other-than-normal" (non-Fickian) diffusion effects, thermodiffusion and gravity action. We evaluate the diffusive flux of aqueous methane and predict the possibility of existence of bubble mass accumulation zones (which can appear independently from the presence/absence of hydrate stability zone) and effect of non-Fickian drift on the capacity of shallow and deep methane-hydrate deposits.

Goldobin, D S; Levesley, J; Lovell, M A; Rochelle, C A; Jackson, P; Haywood, A; Hunter, S; Rees, J

2010-01-01T23:59:59.000Z

63

Modelling and Numerical Simulation of Liquid-Vapor Phase Transition  

E-Print Network [OSTI]

of pressurized water reactors in the nuclear industry. Indeed, understanding the triggering of boiling crisis, temperatures and chemical potentials, which enables dynamic generation of two-phase interfaces within a pure is a critical safety issue for the nuclear industry: when the transition occurs from nucleate boiling to film

Faccanoni, Gloria

64

MODELLING AND SIMULATION OF LIQUID-VAPOR PHASE TRANSITION  

E-Print Network [OSTI]

Generator Turbine Generator Cooling Tower Condenser Cooling Water Pump Reactor Core Reactor Vessel Control and Steam (secondary loop) Water (cooling loop) Pump Steam Generator Turbine Generator Cooling Tower Water pressurized (primary loop) Water and Steam (secondary loop) Water (cooling loop) Pump Steam

Faccanoni, Gloria

65

Gravitational waves, diffusion and decoherence  

E-Print Network [OSTI]

The quite different behaviors exhibited by microscopic and macroscopic systems with respect to quantum interferences suggest that there may exist a naturally frontier between quantum and classical worlds. The value of the Planck mass (22$\\mu$g) may lead to the idea of a connection between this borderline and intrinsic fluctuations of spacetime. We show that it is possible to obtain quantitative answers to these questions by studying the diffusion and decoherence mechanisms induced on quantum systems by gravitational waves generated at the galactic or cosmic scales. We prove that this universal fluctuating environment strongly affects quantum interferences on macroscopic systems, while leaving essentially untouched those on microscopic systems. We obtain the relevant parameters which, besides the ratio of the system's mass to Planck mass, characterize the diffusion constant and decoherence time. We discuss the feasibility of experiments aiming at observing these effects in the context of ongoing progress towar...

Reynaud, Serge; Jaekel, Marc-Thierry

2008-01-01T23:59:59.000Z

66

A continuous reading fluorescence meter for eddy diffusion studies  

E-Print Network [OSTI]

LIBRARY A AIS COLLEGE OF TEXAS A CONTINUOUS READINO FLUORESCENCE METER FOR EDDY DIFFUSION STUDIES BY Frank Wooten Moon, Jr. A Thesis Submitted to ths Qraduate Scbool of the Agricultural and Mechanical College oi' Texas in partial...

Moon, Frank Wooten

1956-01-01T23:59:59.000Z

67

ELEMENTARY DIFFUSION PROCESSES IN ALCUZN ALLOYS: AN AB INITIO STUDY  

E-Print Network [OSTI]

ELEMENTARY DIFFUSION PROCESSES IN AL­CU­ZN ALLOYS: AN AB INITIO STUDY S. GRABOWSKI AND P. ENTEL of alloys such as mechanical strength and toughness, creep and corrosion resistance are essentially

Entel, P.

68

Nonlinear friction in quantum mechanics  

E-Print Network [OSTI]

The effect of nonlinear friction forces in quantum mechanics is studied via dissipative Madelung hydrodynamics. A new thermo-quantum diffusion equation is derived, which is solved for the particular case of quantum Brownian motion with a cubic friction. It is extended also by a chemical reaction term to describe quantum reaction-diffusion systems with nonlinear friction as well.

Roumen Tsekov

2010-03-01T23:59:59.000Z

69

Ambipolar Diffusion in a Magnetic Field  

Science Journals Connector (OSTI)

Diffusion of ions in a plasma across a magnetic field is shown to be not ambipolar in character in most arc experiments. Owing to the highly anisotropic conductivity of the medium, the ions diffuse across the field at their own intrinsic rate. Space-charge neutralization is maintained by slight adjustments of the currents in the direction of the magnetic field lines. The discrepancy between theory and experiment noted by Bohm is thus resolved and no additional mechanisms, such as plasma oscillations, need be postulated.

Albert Simon

1955-04-15T23:59:59.000Z

70

Technology Diffusion and Development  

Science Journals Connector (OSTI)

This chapter discusses the technology diffusion and development that play a key role in climate change mitigation. Most of the authors are engineers with long business experience in this field. In Sect. 9.1, t...

Teruo Okazaki; Mitsutsune Yamaguchi; Hiroyuki Watanabe…

2012-01-01T23:59:59.000Z

71

Enforcement Documents - Portsmouth Gaseous Diffusion Plant | Department of  

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

Portsmouth Gaseous Diffusion Plant Portsmouth Gaseous Diffusion Plant Enforcement Documents - Portsmouth Gaseous Diffusion Plant March 26, 2010 Enforcement Letter, Intennech, Inc. - March 26, 2010 Enforcement Letter issued to Intermech, Inc. related to Installation and Inspection of Anchor Bolts and Pipe Supports at the DUF6 Conversion Buildings at the Portsmouth and Paducah Gaseous Diffusion Plants March 26, 2010 Enforcement Letter, Geiger Brothers Mechanical Contractors, INC - March 26, 2010 Enforcement Letter issued to Geiger Brothers Mechanical Contractors, Inc. related to Installation and Inspection of Penetration Fire Seals at the DUF6 Conversion Building at the Portsmouth Gaseous Diffusion Plant March 26, 2010 Consent Order, Uranium Disposition Services, LLC - NCO-2010-01 Consent Order issued to Uranium Disposition Services, LLC related to

72

Simulations of Xe and U diffusion in UO2  

SciTech Connect (OSTI)

Diffusion of xenon (Xe) and uranium (U) in UO{sub 2} is controlled by vacancy mechanisms and under irradiation the formation of mobile vacancy clusters is important. Based on the vacancy and cluster diffusion mechanisms established from density functional theory (DFT) calculations, we derive continuum thermodynamic and diffusion models for Xe and U in UO{sub 2}. In order to capture the effects of irradiation, vacancies (Va) are explicitly coupled to the Xe and U dynamics. Segregation of defects to grain boundaries in UO{sub 2} is described by combining the bulk diffusion model with models of the interaction between Xe atoms and vacancies with grain boundaries, which were derived from atomistic calculations. The diffusion and segregation models were implemented in the MOOSE-Bison-Marmot (MBM) finite element (FEM) framework and the Xe/U redistribution was simulated for a few simple microstructures.

Andersson, Anders D. [Los Alamos National Laboratory; Vyas, Shyam [Los Alamos National Laboratory; Tonks, Michael R. [Idaho National Laboratory; Casillas, Luis [Los Alamos National Laboratory; Uberuaga, Blas P. [Los Alamos National Laboratory; Millett, Paul [Idaho National Laboratory

2012-09-10T23:59:59.000Z

73

Diffusion Maps for Changing Data Diffusion Maps for Changing Data  

E-Print Network [OSTI]

Diffusion Maps for Changing Data Diffusion Maps for Changing Data Matthew J. Hirn Department;Diffusion Maps for Changing Data Collaborators Ronald Coifman (Yale University) Roy Lederman (Yale University) #12;Diffusion Maps for Changing Data How to compare images across sensors? Figure: Sokolov Mine

Hirn, Matthew

74

Diffusion Maps for Changing Data Diffusion Maps for Changing Data  

E-Print Network [OSTI]

Diffusion Maps for Changing Data Diffusion Maps for Changing Data Matthew J. Hirn Department of Mathematics Yale University July 26, 2012 Bell Labs #12;Diffusion Maps for Changing Data Collaborators Joint work with Ronald Coifman and Roy Lederman. #12;Diffusion Maps for Changing Data Overview 1 High

Hirn, Matthew

75

Diffusion Maps for Changing Data Diffusion Maps for Changing Data  

E-Print Network [OSTI]

Diffusion Maps for Changing Data Diffusion Maps for Changing Data Matthew J. Hirn Department of Mathematics Yale University November 29, 2012 Kansas State University Colloquium #12;Diffusion Maps;Diffusion Maps for Changing Data How to compare images across sensors? Figure: Sokolov Mine in 2009 and 2010

Hirn, Matthew

76

Diffusion Maps for Changing Data Diffusion Maps for Changing Data  

E-Print Network [OSTI]

Diffusion Maps for Changing Data Diffusion Maps for Changing Data Matthew J. Hirn Department in Honor of the 70th Birthday of David R. Larson #12;Diffusion Maps for Changing Data Collaborators Joint work with Ronald Coifman and Roy Lederman. #12;Diffusion Maps for Changing Data High Dimensional Data

Hirn, Matthew

77

Diffusion Maps for Changing Data Diffusion Maps for Changing Data  

E-Print Network [OSTI]

Diffusion Maps for Changing Data Diffusion Maps for Changing Data Matthew J. Hirn September 3, 2013 #12;Diffusion Maps for Changing Data Collaborators Simon Adar, Tel Aviv University Eyal Ben Dor, Tel, Clarkson University Yoel Shkolnisky, Tel Aviv University #12;Diffusion Maps for Changing Data Heat equation

Hirn, Matthew

78

Vacancy Jumps in PdIn: Reconciling Nuclear Relaxation and Diffusion Measurements  

E-Print Network [OSTI]

Vacancy Jumps in PdIn: Reconciling Nuclear Relaxation and Diffusion Measurements Gary S. Collins Keywords: point defect, vacancy, diffusion, defect interaction, intermetallic compound, perturbed angular correlation, PAC, nuclear relaxation, diffusion mechanisms Abstract. Vacancy jump frequencies in PdIn were

Collins, Gary S.

79

Nonnegative Diffusion Orientation Distribution Function  

Science Journals Connector (OSTI)

Because of the well-known limitations of diffusion tensor imaging (DTI) in regions of low anisotropy and multiple fiber crossing, high angular resolution diffusion imaging (HARDI) and Q-Ball Imaging (QBI) are used to estimate the probability density ... Keywords: High angular resolution diffusion imaging (HARDI), Higher order diffusion tensor, Nonnegativity, Orientation distribution function (ODF), Principal direction

Liqun Qi; Gaohang Yu; Yi Xu

2013-02-01T23:59:59.000Z

80

Anomalous diffusion modifies solar neutrino fluxes  

E-Print Network [OSTI]

Density and temperature conditions in the solar core suggest that the microscopic diffusion of electrons and ions could be nonstandard: diffusion and friction coefficients are energy dependent, collisions are not two-body processes and retain memory beyond the single scattering event. A direct consequence of nonstandard diffusion is that the equilibrium energy distribution of particles departs from the Maxwellian one (tails goes to zero more slowly or faster than exponentially) modifying the reaction rates. This effect is qualitatively different from temperature and/or composition modification: small changes in the number of particles in the distribution tails can strongly modify the rates without affecting bulk properties, such as the sound speed or hydrostatic equilibrium, which depend on the mean values from the distribution. This mechanism can considerably increase the range of predictions for the neutrino fluxes allowed by the current experimental values (cross sections and solar properties) and can be u...

Kaniadakis, G; Lissia, M; Quarati, P

1998-01-01T23:59:59.000Z

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


81

Oxygen diffusion in titanite: Lattice diffusion and fast-path diffusion in single crystals  

E-Print Network [OSTI]

Oxygen diffusion in titanite: Lattice diffusion and fast-path diffusion in single crystals X June 2006 Editor: P. Deines Abstract Oxygen diffusion in natural and synthetic single-crystal titanite was characterized under both dry and water-present conditions. For the dry experiments, pre-polished titanite

Watson, E. Bruce

82

The impact of diffusion type on multiscale discrete fracture model numerical simulation for shale gas  

Science Journals Connector (OSTI)

Abstract The development of unconventional gas reservoirs represents totally distinctive characteristics as compared with the conventional reservoirs. The complex pore structure in shale reservoir determines its special flow mechanism, which can be divided into several categories according to the size and type of pores- non Darcy flow, gas slippage, adsorption-desorption and gas diffusion effect. Based on the gas molecules diffusion form in porous media and combining with the multi-scale distribution structural characteristics of shale gas reservoirs, the shale gas diffusion mechanisms in the shale reservoir space including the diffusion of dissolved gases in the organic kerogen and the diffusion of free gas in the nanopores are analyzed in this paper. Meanwhile, the diffusion in the nanopores consists of Knudsen diffusion (KN ? 10), Fick diffusion (KN ? 0.1) and transition diffusion (0.1 shale gas flow in matrix and fracture networks, and also for their mass transfer in between without neglecting its varying-scale nature following the concept of discrete fracture network (DFN). In addition, we also investigate the different diffusion mechanisms' influences on the production and pressure in the tight shale gas reservoir. Ultimately, concluding that the gas diffusion mechanisms in micro-and nano-scale matrix block have a greater impact on the distribution of shale gas production (especially the production at early time) and reservoir pressure.

Lidong Mi; Hanqiao Jiang; Junjian Li

2014-01-01T23:59:59.000Z

83

Physical process Mechanical mechanisms  

E-Print Network [OSTI]

1 Physical process Generation · Mechanical mechanisms F = m·a · Electric/Magnetic mechanisms F ­ Quadrupoles......shear stress fluctuations ­ High order poles...... phys. interpretation difficult Governing

Berlin,Technische Universität

84

Fast diffusion of a graphene flake on a graphene layer  

Science Journals Connector (OSTI)

Diffusion of a graphene flake on a graphene layer is analyzed and a diffusion mechanism is proposed for the system under consideration. According to this mechanism, rotational transition of the flake from commensurate to incommensurate states takes place with subsequent simultaneous rotation and translational motion until the commensurate state is reached again, and so on. The molecular dynamics simulations and analytic estimates based on ab initio and semiempirical calculations demonstrate that the proposed diffusion mechanism is dominant at temperatures T?(1–3)Tcom, where Tcom corresponds to the barrier for transitions of the flake between adjacent energy minima in the commensurate states. For example, for the flake consisting of ?40, 200, and 700 atoms the contribution of the proposed diffusion mechanism through rotation of the flake to the incommensurate states exceeds that for diffusion of the flake in the commensurate states by one to two orders of magnitude at temperatures 50–150 K, 200–600 K, and 800–2400 K, respectively. The possibility to experimentally measure the barriers to relative motion of graphene layers based on the study of diffusion of a graphene flake is considered. The results obtained are also relevant for understanding of dynamic behavior of polycyclic aromatic molecules on graphene and should be qualitatively valid for a set of commensurate adsorbate-adsorbent systems.

Irina V. Lebedeva; Andrey A. Knizhnik; Andrey M. Popov; Olga V. Ershova; Yurii E. Lozovik; Boris V. Potapkin

2010-10-29T23:59:59.000Z

85

First-principles simulations of exciton diffusion in organic semiconductors  

Science Journals Connector (OSTI)

Exciton diffusion is crucial for the performance of organic semiconductors in photovoltaic and solid state lighting applications. We propose a first-principles approach that can predict exciton dynamics in organic semiconductors. The method is based on time-dependent density functional theory to describe the energy and many-body wave functions of excitons. Nonadiabatic ab initio molecular dynamics is used to calculate phonon-assisted transition rates between localized exciton states. Using Monte Carlo simulations, we determine the exciton diffusion length, lifetime, diffusivity, and harvesting efficiency in poly(3-hexylthiophene) polymers at different temperatures, which agree very well with the experiments. We find that exciton diffusion is primarily determined by the density of states of low-energy excitons. A widely speculated diffusion mechanism, namely an initial downhill migration followed by thermally activated migration, is confirmed and elucidated by the simulations. Some general guidelines for designing more efficient organic solar cells are obtained from the simulations.

Xu Zhang; Zi Li; Gang Lu

2011-12-22T23:59:59.000Z

86

OXYGEN DIFFUSION IN HYPOSTOICHIOMETRIC URANIUM DIOXIDE  

E-Print Network [OSTI]

Research Division OXYGEN DIFFUSION IN HYPOSTOICHIOMETRIC11905 -DISCLAIMER - OXYGEN DIFFUSION IN HYPOSTOICHIOMETRICc o n e e n i g woroxygen self-diffusion coefficient

Kim, Kee Chul

2010-01-01T23:59:59.000Z

87

Quantum Markovian activated surface diffusion of interacting adsorbates  

E-Print Network [OSTI]

A quantum Markovian activated atom-surface diffusion model with interacting adsorbates is proposed for the intermediate scattering function, which is shown to be complex-valued and factorizable into a classical-like and a quantum-mechanical factor. Applications to the diffusion of Na atoms on flat (weakly corrugated) and corrugated-Cu(001) surfaces at different coverages and surface temperatures are analyzed. Quantum effects are relevant to diffusion at low surface temperatures and coverages even for relatively heavy particles, such as Na atoms, where transport by tunneling is absent.

R. Martinez-Casado; A. S. Sanz; S. Miret-Artes

2008-03-04T23:59:59.000Z

88

The Impact of Thermal Conductivity and Diffusion Rates on Water Vapor Transport through Gas Diffusion Layers  

E-Print Network [OSTI]

Water management in a hydrogen polymer electrolyte membrane (PEM) fuel cell is critical for performance. The impact of thermal conductivity and water vapor diffusion coefficients in a gas diffusion layer (GDL) has been studied by a mathematical model. The fraction of product water that is removed in the vapour phase through the GDL as a function of GDL properties and operating conditions has been calculated and discussed. Furthermore, the current model enables identification of conditions when condensation occurs in each GDL component and calculation of temperature gradient across the interface between different layers, providing insight into the overall mechanism of water transport in a given cell design. Water transport mode and condensation conditions in the GDL components depend on the combination of water vapor diffusion coefficients and thermal conductivities of the GDL components. Different types of GDL and water removal scenarios have been identified and related to experimentally-determined GDL proper...

Burlatsky, S F; Gummallaa, M; Condita, D; Liua, F

2013-01-01T23:59:59.000Z

89

Diffusive Acceleration of Ions at Interplanetary Shocks  

Science Journals Connector (OSTI)

Heliospheric shocks are excellent systems for testing theories of particle acceleration in their environs. These generally fall into two classes: (1) interplanetary shocks that are linear in their ion acceleration characteristics with the non?thermal ions serving as test particles and (2) non?linear systems such as the Earth’s bow shock and the solar wind termination shock where the accelerated ions strongly influence the magnetohydrodynamic structure of the shock. This paper explores the modelling of diffusive acceleration at a particular interplanetary shock with an emphasis on explaining in situ measurements of ion distribution functions. The observational data for this event was acquired on day 292 of 1991 by the Ulysses mission. The modeling is performed using a well?known kinetic Monte Carlo simulation which has yielded good agreement with observations at several heliospheric shocks as have other theoretical techniques namely hybrid plasma simulations and numerical solution of the diffusion?convection equation. In this theory/data comparison it is demonstrated that diffusive acceleration theory can to first order successfully account for both the proton distribution data near the shock and the observation of energetic protons farther upstream of this interplanetary shock than lower energy pick?up protons using a single turbulence parameter. The principal conclusion is that diffusive acceleration of inflowing upstream ions can model this pick?up ion?rich event without the invoking any seed pre?acceleration mechanism though this investigation does not rule out the action of such pre?acceleration.

Matthew G. Baring; Errol J. Summerlin

2005-01-01T23:59:59.000Z

90

Diffusive Acceleration of Ions at Interplanetary Shocks  

E-Print Network [OSTI]

Heliospheric shocks are excellent systems for testing theories of particle acceleration in their environs. These generally fall into two classes: (1) interplanetary shocks that are linear in their ion acceleration characteristics, with the non-thermal ions serving as test particles, and (2) non-linear systems such as the Earth's bow shock and the solar wind termination shock, where the accelerated ions strongly influence the magnetohydrodynamic structure of the shock. This paper explores the modelling of diffusive acceleration at a particular interplanetary shock, with an emphasis on explaining in situ measurements of ion distribution functions. The observational data for this event was acquired on day 292 of 1991 by the Ulysses mission. The modeling is performed using a well-known kinetic Monte Carlo simulation, which has yielded good agreement with observations at several heliospheric shocks, as have other theoretical techniques, namely hybrid plasma simulations, and numerical solution of the diffusion-convection equation. In this theory/data comparison, it is demonstrated that diffusive acceleration theory can, to first order, successfully account for both the proton distribution data near the shock, and the observation of energetic protons farther upstream of this interplanetary shock than lower energy pick-up protons, using a single turbulence parameter. The principal conclusion is that diffusive acceleration of inflowing upstream ions can model this pick-up ion-rich event without the invoking any seed pre-acceleration mechanism, though this investigation does not rule out the action of such pre-acceleration.

Matthew G. Baring; Errol J. Summerlin

2005-06-08T23:59:59.000Z

91

Electro-diffusion in a plasma with two ion species  

SciTech Connect (OSTI)

Electric field is a thermodynamic force that can drive collisional inter-ion-species transport in a multicomponent plasma. In an inertial confinement fusion capsule, such transport causes fuel ion separation even with a target initially prepared to have equal number densities for the two fuel ion species. Unlike the baro-diffusion driven by ion pressure gradient and the thermo-diffusion driven by ion and electron temperature gradients, electro-diffusion has a critical dependence on the charge-to-mass ratio of the ion species. Specifically, it is shown here that electro-diffusion vanishes if the ion species have the same charge-to-mass ratio. An explicit expression for the electro-diffusion ratio is obtained and used to investigate the relative importance of electro- and baro-diffusion mechanisms. In particular, it is found that electro-diffusion reinforces baro-diffusion in the deuterium and tritium mix, but tends to cancel it in the deuterium and helium-3 mix.

Kagan, Grigory; Tang Xianzhu [Theoretical Division Los Alamos National Laboratory Los Alamos, New Mexico 87545 (United States)

2012-08-15T23:59:59.000Z

92

Particle diffusion in a spheromak  

Science Journals Connector (OSTI)

The local carbon particle diffusion coefficient was measured in the Proto S-1/C spheromak with use of a test-particle injection scheme. When the plasma was not in a force-free Taylor state, and when there were pressure gradients in the plasma, the particle diffusion was 5 times that predicted by Bohm and was consistent with collisional drift-wave diffusion. The diffusion appears to be driven by correlations of the fluctuating electric field and density. During the decay of the discharge when the plasma was in the Taylor state, the diffusion coefficient of the carbon was classical.

D. D. Meyerhofer; F. M. Levinton; M. Yamada

1988-03-07T23:59:59.000Z

93

Enforcement Letter, Geiger Brothers Mechanical Contractors, INC- March 26, 2010  

Broader source: Energy.gov [DOE]

Issued to Geiger Brothers Mechanical Contractors, Inc. related to Installation and Inspection of Penetration Fire Seals at the DUF6 Conversion Building at the Portsmouth Gaseous Diffusion Plant

94

Light diffusing fiber optic chamber  

DOE Patents [OSTI]

A light diffusion system for transmitting light to a target area. The light is transmitted in a direction from a proximal end to a distal end by an optical fiber. A diffusing chamber is operatively connected to the optical fiber for transmitting the light from the proximal end to the distal end and transmitting said light to said target area. A plug is operatively connected to the diffusing chamber for increasing the light that is transmitted to the target area.

Maitland, Duncan J. (Lafayette, CA)

2002-01-01T23:59:59.000Z

95

Reduction of phosphorus diffusion in germanium by fluorine implantation  

SciTech Connect (OSTI)

The control of phosphorus (P) diffusion in germanium (Ge) is essential for the realisation of ultrashallow n-type junctions in Ge. This work reports a detailed study of the effect of fluorine (F) co-implantation on P diffusion in Ge. P and F profiles were characterized by secondary ion mass spectroscopy. The ion implantation damage was investigated using cross sectional transmission electron microscopy. It is shown that F co-implantation reduces the implanted P profile width and reduces both intrinsic and extrinsic P diffusion in Ge. A defect mediated mechanism for the strong influence of F co-implantation on P diffusion in Ge is proposed and invokes the formation of F{sub n}V{sub m} clusters in the F-amorphized Ge layer. A fraction of these F{sub n}V{sub m} clusters decorate the interstitial type end-of-range defects in the re-grown Ge layer and the rest react during re-growth with interstitial germanium atoms diffusing back from the amorphous crystalline interface. The Ge vacancies are then annihilated and mobile interstitial F is released and out diffuses from the surface. This results in a re-grown Ge layer which has a low vacancy concentration and in which the P diffusion rate is reduced. These results open the way to the realization of enhanced Ge n-type devices.

El Mubarek, H. A. W. [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom)

2013-12-14T23:59:59.000Z

96

Thermal diffusion in Au?WTi?Pd metallization on silicon  

Science Journals Connector (OSTI)

This paper presents the results of investigation of thermal diffusion in Au?Wti?Pd metallization on (111) n-Si. Thin films were deposited by dc sputtering to the thickness of 50 (Pd), 100–200 (WTi) and 70–200 nm (Au). After deposition the samples were subjected to thermal treatments vacuum 1 × 10?5 mbar, at temperatures up to 600°C. Characterization included RBS, AES, XRD and SEM structural analysis and sheet resistivity measurements. During annealing up to 450°C diffusion occurs only at the Pd?Si interface, at 500°C other components interdiffuse at isolated areas of the samples and at 600°C there is total interdiffusion on components. Thermal degradation oftthe \\{WTi\\} diffusion barrier is enhanced by the growth of Pd2Si phase, during which silicon is released from the substrate and mechanical stress is introduced. Better diffusion barrier properties were obtained when \\{WTi\\} films were deposited in nitrogen or oxygen atmosphere.

M Milosavljevi?; N Bibi?; M Stojanovi?; J Turkovi?; I.H Wilson

1990-01-01T23:59:59.000Z

97

Enthalpy Diffusion in Multicomponent Flows  

SciTech Connect (OSTI)

The conclusions of this paper are: (1) Enthalpy diffusion preserves the second law. (2) Euler solvers will not produce correct temperatures in mixing regions. (3) Navier-Stokes solvers will only produce correct temperatures if q{sub d} is included. (4) Errors from neglecting enthalpy diffusion are most severe when differences in molecular weights are large. (5) In addition to temperature, enthalpy diffusion affects density, dilatation and other fields in subtle ways. (6) Reacting flow simulations that neglect the term are a dubious proposition. (7) Turbulence models for RANS and LES closures should preserve consistency between energy and species diffusion.

Cook, A W

2009-01-20T23:59:59.000Z

98

Turing instability in reaction-diffusion systems with nonlinear diffusion  

SciTech Connect (OSTI)

The Turing instability is studied in two-component reaction-diffusion systems with nonlinear diffusion terms, and the regions in parametric space where Turing patterns can form are determined. The boundaries between super- and subcritical bifurcations are found. Calculations are performed for one-dimensional brusselator and oregonator models.

Zemskov, E. P., E-mail: zemskov@ccas.ru [Russian Academy of Sciences, Dorodnicyn Computing Center (Russian Federation)

2013-10-15T23:59:59.000Z

99

Anomalous diffusion modifies solar neutrino fluxes  

E-Print Network [OSTI]

Density and temperature conditions in the solar core suggest that the microscopic diffusion of electrons and ions could be nonstandard: Diffusion and friction coefficients are energy dependent, collisions are not two-body processes and retain memory beyond the single scattering event. A direct consequence of nonstandard diffusion is that the equilibrium energy distribution of particles departs from the Maxwellian one (tails goes to zero more slowly or faster than exponentially) modifying the reaction rates. This effect is qualitatively different from temperature and/or composition modification: Small changes in the number of particles in the distribution tails can strongly modify the rates without affecting bulk properties, such as the sound speed or hydrostatic equilibrium, which depend on the mean values from the distribution. This mechanism can considerably increase the range of predictions for the neutrino fluxes allowed by the current experimental values (cross sections and solar properties) and can be used to reduce the discrepancy between these predictions and the solar neutrino experiments.

G. Kaniadakis; A. Lavagno; M. Lissia; P. Quarati

1997-10-16T23:59:59.000Z

100

BDP: BrainSuite Diffusion Pipeline  

E-Print Network [OSTI]

BDP: BrainSuite Diffusion Pipeline Chitresh Bhushan #12; Quantify microstructural tissue ROI Connectivity ROI Statistics MPRAGE Diffusion #12;Diffusion Pipeline Dicom to NIfTI Co ROIs Custom ROIs #12;Diffusion Pipeline Dicom to NIfTI Co-registration Diffusion Modeling Tractography

Leahy, Richard M.

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


101

MEMBRANE FUNCTION, Part 2. Passive Movement: Diffusion, Osmosis, and Gibbs-Donnan Equilibrium 1  

E-Print Network [OSTI]

such as ion gradients or sunlight. I. Passive transport Passive transport is diffusion through a membrane of the membrane. This movement is entirely by the process of diffusion (to be covered below) · ions and polar. Mechanisms of Membrane Transport There are two general modes of transport across membranes: passive transport

Prestwich, Ken

102

Diffusion of Kr Isotopes in Solid Ar  

Science Journals Connector (OSTI)

The diffusion coefficient D=D0e-Q0RT and isotope effect for Kr78 and Kr86 in solid Ar have been measured using a tracer technique. The activation energy QKr0 depends on the interchange parameter w, but is estimated to lie in the range 3500-3900 cal mole-1, with the most reliable w giving the lower value. Thus, the two calculated QKr0 (3853 and 4050 cal mole-1) for the vacancy mechanism using a two-body (12, 6) potential appear somewhat high, but in reasonable agreement with experiment. The isotope effect gives f?K?(D78D86-1)[(8678)12-1]=0.48±0.25 which, since QKr0?QAr0, suggests that ?K?0.6 for a single-vacancy mechanism. {Here f is the correlation factor and ?K?(?278?286-1)[(8678)12-1], where ?2 is the tracer jump rate.}

E. H. C. PARKER; B. L. SMITH; H. R. GLYDE

1969-12-15T23:59:59.000Z

103

Molecular imaging of water binding state and diffusion in breast cancer using diffuse optical spectroscopy and diffusion weighted MRI  

E-Print Network [OSTI]

Molecular imaging of water binding state and diffusion inChung et al. , “In vivo water state measurements in breastby measuring tis- sue water state using diffuse optical

Chung, So Hyun; Yu, Hon; Su, Min-Ying; Cerussi, Albert E.; Tromberg, Bruce J.

2012-01-01T23:59:59.000Z

104

Evaluations of nutrient diffusing substrates and the primary importance of light in controlling periphyton  

E-Print Network [OSTI]

eutrophication. In the first study, artificial channels were used to investigate the response of periphyton to different nutrient delivery mechanisms. In two channels, nutrients were delivered via diffusion to periphyton growth surfaces using modified Matlock...

Murawski, Matthew Thomas

2012-06-07T23:59:59.000Z

105

ELEMENTARY DIFFUSION PROCESSES IN AL-CU-ZN ALLOYS: AN AB INITIO STUDY  

E-Print Network [OSTI]

ELEMENTARY DIFFUSION PROCESSES IN AL-CU-ZN ALLOYS: AN AB INITIO STUDY S. GRABOWSKI AND P. ENTEL of alloys such as mechanical strength and toughness, creep and corrosion resistance are essentially

Entel, P.

106

Active Diffusion of Motor Particles  

Science Journals Connector (OSTI)

The movement of motor particles consisting of one or several molecular motors bound to a cargo particle is studied theoretically. The particles move on patterns of immobilized filaments. Several patterns are described for which the motor particles undergo nondirected but enhanced diffusion. Depending on the walking distance of the particles and the mesh size of the patterns, the active diffusion coefficient exhibits three different regimes. For micrometer-sized motor particles in water, e.g., this diffusion coefficient can be enhanced by 2 orders of magnitude.

Stefan Klumpp and Reinhard Lipowsky

2005-12-23T23:59:59.000Z

107

Prediction of Room Air Diffusion for Reduced Diffuser Flow Rates  

E-Print Network [OSTI]

modeling at the air supply device (ASHRAE Research Project RP -1009, ?Simplified Diffuser Boundary Conditions for Numerical Room Airflow Models, 2001) 2.2.4 Box model Nielsen (1989, 1992) proposed the box method with an imaginary box near.... Nielsen (1989, 13 1992). Results obtained from the box method are in good agreement with the measured data. Figure 5 Methods for momentum modeling in front of an air supply device (ASHRAE RP -1009, ?Simplified Diffuser Boundary Conditions...

Gangisetti, Kavita

2011-02-22T23:59:59.000Z

108

AMEAerospace & Mechanical  

E-Print Network [OSTI]

AMEAerospace & Mechanical Engineering #12;Aerospace and Mechanical Engineers design complex mechanical, thermal, fluidic, acousti- cal, optical, and electronic systems, with char- acteristic sizes space. Aerospace and Mechanical Engineering (AME) students conduct basic and applied research within

Wang, Hai

109

Anisotropic diffusion of hydrogen atoms on the Si(100)-2×1 surface  

Science Journals Connector (OSTI)

This paper presents first-principles total-energy calculations of hydrogen-adatom diffusion on a Si(100)-2×1 reconstructed surface. The transition states for hydrogen-atom-diffusion pathways were established by mapping out the potential energy of a hydrogen atom jumping between the dangling bonds of a Si(100)-2×1 surface modeled by embedded finite silicon clusters. The diffusion barriers are high (2–3 eV) and wide (?3–4 Å), suggesting that H-atom diffusion on Si(100) proceeds via mostly a classical hopping mechanism instead of tunneling. Furthermore, diffusion of hydrogen atoms is predicted to be anisotropic, being preferentially directed parallel to the silicon-dimer rows, with an activation energy of 2.0 eV. Higher activation energies of 2.5 and 2.7 eV are predicted for diffusion perpendicular to dimer rows, for the cases of hydrogen atoms hopping from one dangling bond to a neighboring dangling bond on the same dimer and on an adjacent dimer, respectively. The mechanism for H-atom diffusion along dimer rows is markedly different from that previously proposed for Si-adatom diffusion on Si(100): H atoms are predicted to diffuse along edges of the dimer rows rather than down the middle.

Christine J. Wu and Emily A. Carter

1992-08-15T23:59:59.000Z

110

Hot carrier diffusion in graphene  

E-Print Network [OSTI]

We report an optical study of charge transport in graphene. Diffusion of hot carriers in epitaxial graphene and reduced graphene oxide samples are studied using an ultrafast pump-probe technique with a high spatial resolution. Spatiotemporal...

Ruzicka, Brian Andrew; Wang, Shuai; Werake, Lalani Kumari; Weintrub, Ben; Loh, Kian Ping; Zhao, Hui

2010-11-01T23:59:59.000Z

111

Accelerating and Retarding Anomalous Diffusion  

E-Print Network [OSTI]

In this paper Gaussian models of retarded and accelerated anomalous diffusion are considered. Stochastic differential equations of fractional order driven by single or multiple fractional Gaussian noise terms are introduced to describe retarding and accelerating subdiffusion and superdiffusion. Short and long time asymptotic limits of the mean squared displacement of the stochastic processes associated with the solutions of these equations are studied. Specific cases of these equations are shown to provide possible descriptions of retarding or accelerating anomalous diffusion.

Chai Hok Eab; S. C. Lim

2012-01-14T23:59:59.000Z

112

Diffusion mechanisms in metallic supercooled liquids and glasses  

Science Journals Connector (OSTI)

... K for 9Be). It was shown recently that the 9Be spin alignment echo technique (SAE) is very effective in detecting Be hopping in glassy Vit1 and Vit4 with atomic ... Vit1 and Vit4 with atomic jump rates as low as 0.1 s-1. The SAE technique is based on the Jeener–Broekaert sequence 90°x–?1–45°y–?–45 ...

X.-P. Tang; Ulrich Geyer; Ralf Busch; William L. Johnson; Yue Wu

1999-11-11T23:59:59.000Z

113

Diffusion in confinement as a microscopic relaxation mechanism...  

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

form 27 January 2012 Available online 4 February 2012 a b s t r a c t Using quasielastic neutron scattering, we compare dynamics in single-element liquids, glass-forming selenium...

114

Modeling gas displacement kinetics in coal with Maxwell-Stefan diffusion theory  

SciTech Connect (OSTI)

The kinetics of binary gas counter-diffusion and Darcy flow in a large coal sample were modeled, and the results compared with data from experimental laboratory investigations. The study aimed for a better understanding of the CO{sub 2}-sequestration enhanced coalbed methane (ECBM) recovery process. The transport model used was based on the bidisperse diffusion mechanism and Maxwell-Stefan (MS) diffusion theory. This provides an alternative approach to simulate multicomponent gas diffusion and flow in bulk coals. A series of high-stress core flush tests were performed on a large coal sample sourced from a Bowen Basin coal mine in Queensland, Australia to investigate the kinetics of one gas displacing another. These experimental results were used to derive gas diffusivities, and to examine the predictive capability of the diffusion model. The simulations show good agreements with the displacement experiments revealing that MS diffusion theory is superior for describing diffusion of mixed gases in coals compared with the constant Fick diffusivity model. The optimized effective micropore and macropore diffusivities are comparable with experimental measurements achieved by other researchers.

Wei, X.R.; Wang, G.X.; Massarotto, P.; Rudolph, V.; Golding, S.D. [University of Queensland, Brisbane, Qld. (Australia). Division of Chemical Engineering

2007-12-15T23:59:59.000Z

115

Nitrogen self-diffusion in magnetron sputtered Si-C-N films  

SciTech Connect (OSTI)

Self-diffusion was studied in magnetron sputtered nitrogen-rich amorphous compounds of the system Si-C-N by using nitrogen as a model tracer. As shown by infra-red spectroscopy a transient metastable region exists, where the structure of the material can be visualized as silicon nitride tetrahedra which are connected by carbo-diimide (-N=C=N-) bonds to a three dimensional amorphous network. In this region diffusion studies are carried out by neutron reflectometry and isotope multilayers as a function of annealing time, temperature and chemical composition. Low diffusivities between 10{sup -20} and 10{sup -24} m{sup 2}/s were found. In the metastable region, diffusion is faster than diffusion in amorphous silicon nitride by 1 to 2 orders of magnitude, while the activation enthalpies of diffusion between 3.1 and 3.4 eV are the same within error limits. This can be explained by the fact that the diffusion mechanism along SiN{sub 4} tetrahedra is identical to that in amorphous silicon nitride, however, the carbo-diimide bonds seem to widen the structure, allowing faster diffusion. A correlation between diffusivities and the number of carbo-diimid bonds present in the material is found, where the highest diffusivities are observed for materials with the highest number of carbo-diimid bonds, close to the composition Si{sub 2}CN{sub 4}.

Hueger, E.; Schmidt, H. [Institute of Metallurgy, Materials Physics Group, Clausthal University of Technology, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany); Geue, T.; Stahn, J. [Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Tietze, U.; Lott, D. [Helmholtz-Zentrum Geesthacht, Max Planck Str. 1, D-21502 Geesthacht (Germany); Markwitz, A. [National Isotope Centre, GNS Science, 30 Gracefield Road, PO Box 31-312 Lower Hutt (New Zealand); Geckle, U.; Bruns, M. [Institute for Materials Research III, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

2011-05-01T23:59:59.000Z

116

Chapter 1 - Introduction to Diffusion MR  

Science Journals Connector (OSTI)

Abstracts Developments in the last century have led to a better understanding of diffusion—the perpetual mixing of molecules caused by thermal motion. In this chapter, the basic principles governing the diffusion phenomenon and its measurement using magnetic resonance (MR) are reviewed. The concepts of the apparent diffusion coefficient and of the diffusion propagator as well as their MR measurements are introduced from basic principles. Finally, the influence of neural tissue microstructure on the diffusion-weighted MR signal is briefly discussed.

Peter J. Basser; Evren Özarslan

2014-01-01T23:59:59.000Z

117

Commercial Building Partnerships Replication and Diffusion  

SciTech Connect (OSTI)

This study presents findings from survey and interview data investigating replication efforts of Commercial Building Partnership (CBP) partners that worked directly with the Pacific Northwest National Laboratory (PNNL). PNNL partnered directly with 12 organizations on new and retrofit construction projects, which represented approximately 28 percent of the entire U.S. Department of Energy (DOE) CBP program. Through a feedback survey mechanism, along with personal interviews, PNNL gathered quantitative and qualitative data relating to replication efforts by each organization. These data were analyzed to provide insight into two primary research areas: 1) CBP partners’ replication efforts of technologies and approaches used in the CBP project to the rest of the organization’s building portfolio (including replication verification), and, 2) the market potential for technology diffusion into the total U.S. commercial building stock, as a direct result of the CBP program. The first area of this research focused specifically on replication efforts underway or planned by each CBP program participant. Factors that impact replication include motivation, organizational structure and objectives firms have for implementation of energy efficient technologies. Comparing these factors between different CBP partners revealed patterns in motivation for constructing energy efficient buildings, along with better insight into market trends for green building practices. The second area of this research develops a diffusion of innovations model to analyze potential broad market impacts of the CBP program on the commercial building industry in the United States.

Antonopoulos, Chrissi A.; Dillon, Heather E.; Baechler, Michael C.

2013-09-16T23:59:59.000Z

118

Hot carrier diffusion in graphene  

Science Journals Connector (OSTI)

We report an optical study of charge transport in graphene. Diffusion of hot carriers in epitaxial graphene and reduced graphene-oxide samples are studied using an ultrafast pump-probe technique with a high spatial resolution. Spatiotemporal dynamics of hot carriers after a pointlike excitation are monitored. Carrier-diffusion coefficients of 11?000 and 5500?cm2?s?1 are measured in epitaxial graphene and reduced graphene-oxide samples, respectively, with a carrier temperature on the order of 3600 K. The demonstrated optical techniques can be used for noncontact and noninvasive in situ detection of transport properties of graphene.

Brian A. Ruzicka; Shuai Wang; Lalani K. Werake; Ben Weintrub; Kian Ping Loh; Hui Zhao

2010-11-08T23:59:59.000Z

119

Phase Diffusion in Graphene-Based Josephson Junctions I. V. Borzenets, U. C. Coskun, S. J. Jones, and G. Finkelstein  

E-Print Network [OSTI]

Phase Diffusion in Graphene-Based Josephson Junctions I. V. Borzenets, U. C. Coskun, S. J. Jones July 2011; published 21 September 2011) We report on graphene-based Josephson junctions with contacts. We attribute this resistance to the phase diffusion mechanism, which has not been yet identified

Finkelstein, Gleb

120

Diffusion in a potential landscape with stochastic resetting  

E-Print Network [OSTI]

The steady state of a Brownian particle diffusing in an arbitrary potential under the stochastic resetting mechanism has been studied. We show that there are different classes of nonequilibrium steady states depending on the nature of the potential. In the stable potential landscape, the system attains a well defined steady state however existence of the steady state for the unstable landscape is constrained. We have also investigated the transient properties of the propagator towards the steady state under the stochastic resetting mechanism. Finally, we have done numerical simulations to verify our analytical results.

Arnab Pal

2014-08-09T23:59:59.000Z

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


121

Acetone-Assisted Oxygen Vacancy Diffusion on TiO2(110)  

SciTech Connect (OSTI)

We have studied the dynamic relationship between acetone and bridge-bonded oxygen (Ob) vacancy (VO) defect sites on the TiO2(110)-1 × 1 surface using scanning tunneling microscopy (STM) and density function theory (DFT) calculations. We report an adsorbate-assisted VO diffusion mechanism. The STM images taken at 300 K show that acetone preferably adsorbs on the VO site and is mobile. The sequential isothermal STM images directly show that the mobile acetone effectively migrates the position of VO by a combination of two acetone diffusion channels: one is the diffusion along the Ob row and moving as an alkyl group, which heals the initial VO; another is the diffusion from the Ob row to the fivecoordinated Ti4+ row and then moving along the Ti4+ row as an acetone, which leaves a VO behind. The calculated acetone diffusion barriers for the two channels are comparable and agree with experimental results.

Xia, Yaobiao; Zhang, Bo; Ye, Jingyun; Ge, Qingfeng; Zhang, Zhenrong

2012-10-18T23:59:59.000Z

122

Nitrogen Diffusion in Amorphous Silicon Nitride Isotope Multilayers Probed by Neutron Reflectometry  

Science Journals Connector (OSTI)

Amorphous silicon nitride is a model system for a covalently bound amorphous solid with a low atomic mobility where reasonable values of self-diffusivities are still lacking. We used neutron reflectometry on isotope enriched Si3?N414/Si3?N415 multilayers to determine nitrogen self-diffusivities ranging from 10-24 to 10-21??m2/s between 950 and 1250?°C. Time dependent diffusivities observed at 1150?°C indicate the presence of structural relaxation. For long annealing times (relaxed state) the diffusivities follow an Arrhenius law with an activation enthalpy of (3.6±0.4)??eV. The results are indicative of a direct diffusion mechanism without the involvement of thermal point defects.

H. Schmidt; M. Gupta; M. Bruns

2006-02-07T23:59:59.000Z

123

Nitrogen Diffusion in Amorphous Silicon Nitride Isotope Multilayers Probed by Neutron Reflectometry  

SciTech Connect (OSTI)

Amorphous silicon nitride is a model system for a covalently bound amorphous solid with a low atomic mobility where reasonable values of self-diffusivities are still lacking. We used neutron reflectometry on isotope enriched Si{sub 3} {sup 14}N{sub 4}/Si{sub 3} {sup 15}N{sub 4} multilayers to determine nitrogen self-diffusivities ranging from 10{sup -24} to 10{sup -21} m{sup 2}/s between 950 and 1250 deg. C. Time dependent diffusivities observed at 1150 deg. C indicate the presence of structural relaxation. For long annealing times (relaxed state) the diffusivities follow an Arrhenius law with an activation enthalpy of (3.6{+-}0.4) eV. The results are indicative of a direct diffusion mechanism without the involvement of thermal point defects.

Schmidt, H.; Gupta, M.; Bruns, M. [AG Thermochemie und Mikrokinetik, Fakultaet fuer Natur-und Materialwissenschaften, TU Clausthal, D-38678 Clausthal-Zellerfeld (Germany); Laboratory for Neutron Scattering, ETH Zuerich and PSI, Paul Scherrer Institute, Villigen, CH-5232 (Switzerland); Institut fuer Instrumentelle Analytik, Forschungszentrum Karlsruhe GmbH, D-76021 Karlsruhe (Germany)

2006-02-10T23:59:59.000Z

124

Hierarchical 3D diffusion wavelet shape priors  

E-Print Network [OSTI]

In this paper, we propose a novel representation of prior knowledge for image segmentation, using diffusion wavelets that can reflect arbitrary continuous interdependencies in shape data. The application of diffusion ...

Langs, Georg

125

Efficient Stochastic Galerkin Methods For Random Diffusion ...  

E-Print Network [OSTI]

We discuss in this paper simulations of diffusion problems ... With PC/gPC serving as a complete basis to represent random processes, a stochastic Galerkin ... coupled diffusion equations, which can be readily written in a vector/

2008-09-16T23:59:59.000Z

126

MICROFLUIDIC CONTROL OF STEM CELL DIFFUSIBLE SIGNALING  

E-Print Network [OSTI]

MICROFLUIDIC CONTROL OF STEM CELL DIFFUSIBLE SIGNALING Katarina Blagovi, Lily Y. Kim, Alison M cell differentiation. KEYWORDS: Embryonic stem cells, microfluidic perfusion, diffusible signaling; they secrete molecules to which they respond. Microfluidics offers a potential solution to this challenge

Voldman, Joel

127

Diffusion stability of bubbles in a cluster  

Science Journals Connector (OSTI)

The diffusion stability of gas bubbles in one-fraction and two-fraction clusters ... gas concentrations in the liquid at which the bubble tends to one of two equilibrium states because of diffusion processes betw...

É. Sh. Nasibullaeva; I. Sh. Akhatov

2007-07-01T23:59:59.000Z

128

OXYGEN DIFFUSION IN UO2-x  

E-Print Network [OSTI]

~ K.C. K:i.m, "Oxygen Diffusion in Hypostoichiometricsystem for enriching uo 2 in oxygen-18 or for stoichiometry+nal of Nuclear Materials OXYGEN DIFFUSION IN U0 2 _:x K.C.

Kim, K.C.

2013-01-01T23:59:59.000Z

129

Cysteamine-induced inhibition of acid neutralization and the increase in hydrogen ion back-diffusion in duodenal mucosa  

Science Journals Connector (OSTI)

To investigate the possible impairment of defensive mechanisms in cysteamine-induced duodenal ulceration, the effect of cysteamine on the neutralization of acid by the duodenum and the back-diffusion of hydrog...

Dr. Keiji Ohe MD; DMSc; Yoshiomi Okada MD…

1982-03-01T23:59:59.000Z

130

Heat Hyperbolic Diffusion in Planck Gas  

E-Print Network [OSTI]

In this paper we investigate the diffusion of the thermal pulse in Planck Gas. We show that the Fourier diffusion equation gives the speed of diffusion, v > c and breaks the causality of the thermal processes in Planck gas .For hyperbolic heat transport v

Miroslaw Kozlowski; Janina Marciak-Kozlowska

2006-07-06T23:59:59.000Z

131

Nanoparticle Diffusion in Polymer Nanocomposites  

Science Journals Connector (OSTI)

Large-scale molecular dynamics simulations show that nanoparticle (NP) diffusivity in weakly interacting mixtures of NPs and polymer melts has two very different classes of behavior depending on their size. NP relaxation times and their diffusivities are completely described by the local, Rouse dynamics of the polymer chains for NPs smaller than the polymer entanglement mesh size. The motion of larger NPs, which are comparable to the entanglement mesh size, is significantly slowed by chain entanglements, and is not describable by the Stokes-Einstein relationship. Our results are in essentially quantitative agreement with a force-level generalized Langevin equation theory for all the NP sizes and chain lengths explored, and imply that for these lightly entangled systems, activated NP hopping is not important.

Jagannathan T. Kalathi; Umi Yamamoto; Kenneth S. Schweizer; Gary S. Grest; Sanat K. Kumar

2014-03-12T23:59:59.000Z

132

Determination of effective water vapor diffusion coefficient in pemfc gas diffusion layers  

E-Print Network [OSTI]

route from the cathode catalyst layer to the cathode flow channels. Water can be removed from the cellDetermination of effective water vapor diffusion coefficient in pemfc gas diffusion layers Jacob M: Water vapor diffusion PEMFC Water management GDL Diffusivity MPL a b s t r a c t The primary removal

Kandlikar, Satish

133

Comparison of \\{WTi\\} and WTi(N) as diffusion barriers for Al and Cu metallization on Si with respect to thermal stability and diffusion behavior of Ti  

Science Journals Connector (OSTI)

Abstract The thermal stability of \\{WTi\\} and WTi(N) as diffusion barriers for Al and Cu metallization on Si (1 0 0) was investigated by time of flight secondary ion mass spectrometry (ToF-SIMS) depth profiling, X-ray diffraction (XRD), electron microscopy (SEM and TEM) and X-ray photoelectron spectroscopy (XPS). For both, Al and Cu, Ti diffusion out of \\{WTi\\} into the metal was proved to occur at elevated temperatures (400 °C for Al and 600 °C for Cu) which further results in barrier film failure. Nitrogen incorporation into \\{WTi\\} leads to an elimination of the Ti diffusion and consequently to a better thermal stability of the barrier film. It is shown that besides crystal structure, Ti diffusion into the metallization is an essential factor of the barrier failure mechanism. The failure temperature for Al is lower than for Cu.

M. Fugger; M. Plappert; C. Schäffer; O. Humbel; H. Hutter; H. Danninger; M. Nowottnick

2014-01-01T23:59:59.000Z

134

Ice-water and liquid-vapor phase transitions by a Ginzburg–Landau model  

Science Journals Connector (OSTI)

A model for the first order phase transitions as ice-water and liquid-vapor is proposed using the Ginzburg–Landau equation for the order parameter ? . In this model the density ? is composed of two quantities ? 0 and ? 1 such that 1 / ? = 1 / ? 0 + 1 / ? 1 where ? 1 is strictly connected to the order parameter ? . By means of this decomposition we are able to represent the Andrew diagram without the use of the heuristic van der Waals equation.

Mauro Fabrizio

2008-01-01T23:59:59.000Z

135

Bundles of carbon nanotubes generated by vapor-phase growth Maohui Ge and Klaus Sattler  

E-Print Network [OSTI]

Z.t They were initially found at the end of an electrode in the arc discharge method and were later produced, thinning and opening of the tubes by oxidation was observed.4v5In the arc discharge method the generation of the tubes might be initiated by the substrate and proceed due to the electric field between the two elec

Sattler, Klaus

136

A Gas Lift Bioreactor for Removal of Contaminants from the Vapor Phase  

Science Journals Connector (OSTI)

...conditions, and the reactor was again allowed...of samplings and analysis took place. The...while maintaining reliability of the degradative...was fed into the reactor inlet at different...phenol found in the reactor contents unless...be detected by GC analysis under the conditions...

B. D. Ensley; P. R. Kurisko

1994-01-01T23:59:59.000Z

137

High Rates of Oxygen Reduction over a Vapor Phase–Polymerized PEDOT Electrode  

Science Journals Connector (OSTI)

...electrode. Recently, the development of chemical polymerization...application of the PEDOT electrocatalyst concept would require...from the anode to the cathode is a major issue in...2 reduction on the cathode side (9). In...31). Thus, the development of the gas-ICP-electrolyte...

Bjorn Winther-Jensen; Orawan Winther-Jensen; Maria Forsyth; Douglas R. MacFarlane

2008-08-01T23:59:59.000Z

138

Desalination-of water by vapor-phase transport through hydrophobic nanopores  

E-Print Network [OSTI]

We propose a new approach to desalination of water whereby a pressure difference across a vapor-trapping nanopore induces selective transport of water by isothermal evaporation and condensation across the pore. Transport ...

Lee, Jongho

139

Controlled Vapor Phase Growth of Single Crystalline, Two-Dimensional GaSe  

E-Print Network [OSTI]

, and have the potential to enable next-generation electronic and optoelectronic devices. However, controlled-generation electronic and optoelectronic devices such as photodetectors and field-effect transistors. T wo-generation electronic and optoelectronic devices. Although most research has focused on 2D transition metal

Geohegan, David B.

140

THz Quantum Cascade Lasers Grown by Low-Pressure Metalorganic Vapor Phase Epitaxy  

Science Journals Connector (OSTI)

A terahertz quantum cascade laser (QCL) has been successfully grown by low-pressure MOVPE. Very high quality semiconductor interfaces are demonstrated as well as very promising lasing...

Sirigu, Lorenzo; Rudra, Alok; Amanti, Maria I; Scalari, Giacomo; Fischer, Milan; Giovannini, Marcella; Faist, Jerome; Kapon, Eli

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


141

Ion-beam-induced epitaxial vapor-phase growth: A molecular-dynamics study  

Science Journals Connector (OSTI)

Low-energy ions which bombard a vapor-deposited film of low adatom mobility during growth mobilize surface atoms in the vicinity of the ion impact, causing a modification in the evolving microstructure. In a two-dimensional molecular-dynamics simulation where inert-gas ions strike a growing film of Lennard-Jones particles, it is demonstrated that ion bombardment during growth causes the filling of voids quenched in during vapor condensation and induces homoepitaxial growth. The dependence of film density and degree of homoepitaxial growth on the ion-to-vapor arrival rate ratio and ion energy is studied in detail.

Karl-Heinz Müller

1987-05-15T23:59:59.000Z

142

Independent Oversight Inspection, Portsmouth Gaseous Diffusion Plant -  

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

Portsmouth Gaseous Diffusion Portsmouth Gaseous Diffusion Plant - November 2006 Independent Oversight Inspection, Portsmouth Gaseous Diffusion Plant - November 2006 November 2006 Inspection of Emergency Management at the Portsmouth Gaseous Diffusion Plant The Secretary of Energy's Office of Independent Oversight, within the Office of Security and Safety Performance Assurance, conducted an inspection of the emergency management program at the Portsmouth Gaseous Diffusion Plant (PORTS) in August and September 2006. The coordination of emergency plans and procedures among USEC and DOE contractor organizations has successfully integrated the emergency management programs into a single cohesive program for the PORTS site. Other strengths include accurate hazards surveys that identify applicable

143

Vacancy Mechanism Davydov I.А.  

National Nuclear Security Administration (NNSA)

9: Computational Physics-MD 9: Computational Physics-MD DFT and MD Simulation of Self-Diffusion in Silicon: Study of Diffusion Vacancy Mechanism Davydov I.А. * , Anisin А.V. † , Eliseev G.М. ‡ , Kopkin S.V. § , and Reese Jones ** *, †, ‡, § Russian Federal Nuclear Center - All-Russia Research Institute of Experimental Physics (RFNC-VNIIEF), 607190 Sarov, Mira-37, Russia ** Sandia National Laboratories, MS 9404, P.O. Box 0969, Livermore, CA 94551, USA Summary: Computations of jump activation energy DH j and diffusion jump frequency n have been carried out using the Density Functional Theory (DFT) and Molecular Dynamics (MD) method for a single crystal of Si. These parameters define the rate of vacancy diffusion transport.

144

An asixymmetric diffusion experiment for the determination of diffusion and sorption coefficients of rock samples  

SciTech Connect (OSTI)

Diffusion anisotropy is a critical property in predicting migration of substances in sedimentary formations with very low permeability. The diffusion anisotropy of sedimentary rocks has been evaluated mainly from laboratory diffusion experiments, in which the directional diffusivities are separately estimated by through-diffusion experiments using different rock samples, or concurrently by in-diffusion experiments in which only the tracer profile in a rock block is measured. To estimate the diffusion anisotropy from a single rock sample, this study proposes an axisymmetric diffusion test, in which tracer diffuses between a cylindrical rock sample and a surrounding solution reservoir. The tracer diffusion between the sample and reservoir can be monitored from the reservoir tracer concentrations, and the tracer profile could also be obtained after dismantling the sample. Semi-analytical solutions are derived for tracer concentrations in both the reservoir and sample, accounting for an anisotropic diffusion tensor of rank two as well as the dilution effects from sampling and replacement of reservoir solution. The transient and steady-state analyses were examined experimentally and numerically for different experimental configurations, but without the need for tracer profiling. These experimental configurations are tested for in- and out-diffusion experiments using Koetoi and Wakkanai mudstones and Shirahama sandstone, and are scrutinized by a numerical approach to identify favorable conditions for parameter estimation. The analysis reveals the difficulty in estimating diffusion anisotropy; test configurations are proposed for enhanced identifiability of diffusion anisotropy. Moreover, it is demonstrated that the axisymmetric diffusion test is efficient in obtaining the sorption parameter from both steady-state and transient data, and in determining the effective diffusion coefficient if isotropic diffusion is assumed. Moreover, measuring reservoir concentrations in an axisymmetric diffusion experiment coupled with tracer profiling may be a promising approach to estimate of diffusion anisotropy of sedimentary rocks.

Takeda, M.; Hiratsuka, T.; Ito, K.; Finsterle, S.

2011-02-01T23:59:59.000Z

145

Neutrino diffusion and mass ejection in protoneutron stars  

SciTech Connect (OSTI)

We discuss the mass ejection mechanism induced by diffusion of neutrino during the early stage of the protoneutron star cooling. A dynamical calculation is employed in order to determine the amount of matter ejected and the remnant compact object mass. An equation of state considering hadronic and quark phases for the stellar dense matter was used to solve the whole time evolution of the system during the cooling phase. The initial neutrino population was obtained by considering beta equilibrium in the dense stellar matter with confined neutrinos, in the very early period of the deleptonic stage of the nascent pulsar. For specified initial configurations of the protoneutron star, we solve numerically the set of equations of motion together with neutrino diffusion through the dense stellar medium.

Almeida, L. G. [Universidade Federal do Acre-Campus Floresta, Estrada do Canela Fina, km 12, 69980-000, Cruzeiro do Sul, AC (Brazil); Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ (Brazil); Rodrigues, H.; Portes, D. Jr. [Centro Federal de Educacao Tecnologica do Rio de Janeiro, Av. Maracana 249, 20271-110, Rio de Janeiro, RJ (Brazil); Duarte, S. B. [Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ (Brazil)

2010-11-15T23:59:59.000Z

146

AMBIPOLAR DIFFUSION HEATING IN TURBULENT SYSTEMS  

SciTech Connect (OSTI)

The temperature of the gas in molecular clouds is a key determinant of the characteristic mass of star formation. Ambipolar diffusion (AD) is considered one of the most important heating mechanisms in weakly ionized molecular clouds. In this work, we study the AD heating rate using two-fluid turbulence simulations and compare it with the overall heating rate due to turbulent dissipation. We find that for observed molecular clouds, which typically have Alfven Mach numbers of {approx}1 and AD Reynolds numbers of {approx}20, about 70% of the total turbulent dissipation is in the form of AD heating. AD has an important effect on the length scale where energy is dissipated: when AD heating is strong, most of the energy in the cascade is removed by ion-neutral drift, with a comparatively small amount of energy making it down to small scales. We derive a relation for the AD heating rate that describes the results of our simulations to within a factor of two. Turbulent dissipation, including AD heating, is generally less important than cosmic-ray heating in molecular clouds, although there is substantial scatter in both.

Li, Pak Shing [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Myers, Andrew [Physics Department, University of California, Berkeley, CA 94720 (United States); McKee, Christopher F., E-mail: psli@astron.berkeley.edu, E-mail: atmyers@berkeley.edu, E-mail: cmckee@berkeley.edu [Physics Department and Astronomy Department, University of California, Berkeley, CA 94720 (United States)

2012-11-20T23:59:59.000Z

147

Characterizing unsaturated diffusion in porous tuff gravel  

SciTech Connect (OSTI)

Evaluation of solute diffusion in unsaturated porous gravel is very important for investigations of contaminant transport and remediation, risk assessment, and waste disposal (for example, the potential high-level nuclear waste repository at Yucca Mountain, Nevada). For a porous aggregate medium such as granular tuff, the total water content is comprised of surface water and interior water. The surface water component (water film around grains and pendular water between the grain contacts) could serve as a predominant diffusion pathway. To investigate the extent to which surface water films and contact points affect solute diffusion in unsaturated gravel, we examined the configuration of water using x-ray computed tomography in partially saturated gravel, and made quantitative measurements of diffusion at multiple water contents using two different techniques. In the first, diffusion coefficients of potassium chloride in 2-4 mm granular tuff at multiple water contents were calculated from electrical conductivity measurements using the Nernst-Einstein equation. In the second, we used laser ablation with inductively coupled plasma-mass spectrometry to perform micro-scale mapping, allowing the measurement of diffusion coefficients for a mixture of chemical tracers for tuff cubes and tetrahedrons having two contact geometries (cube-cube and cube-tetrahedron). The x-ray computed tomography images show limited contact between grains, and this could hinder the pathways for diffusive transport. Experimental results show the critical role of surface water in controlling transport pathways and hence the magnitude of diffusion. Even with a bulk volumetric water content of 1.5%, the measured solute diffusion coefficient is as low as 1.5 x 10{sup -14} m{sup 2}/s for tuff gravel. Currently used diffusion models relating diffusion coefficients to total volumetric water content inadequately describe unsaturated diffusion behavior in porous gravel at very low water contents.

Hu, Qinhong; Kneafsey, Timothy J.; Roberts, Jeffery J.; Tomutsa, Liviu; Wang, Joseph, S.Y.

2003-11-12T23:59:59.000Z

148

Diffusion in Porous Catalysts and Adsorbents  

Science Journals Connector (OSTI)

Diffusion in Porous Catalysts and Adsorbents ... Single industrial adsorbent pellets of zeolites 5A and 13X were mounted with a polymer capable of withstanding high temperatures. ...

Jan Hoogschagen

1955-01-01T23:59:59.000Z

149

Self-Similar Modes of Coherent Diffusion  

E-Print Network [OSTI]

Self-similar solutions of the coherent diffusion equation are derived and measured. The set of real similarity solutions is generalized by the introduction of a nonuniform phase surface, based on the elegant Gaussian modes of optical diffraction. In an experiment of light storage in a gas of diffusing atoms, a complex initial condition is imprinted, and its diffusion dynamics is monitored. The self-similarity of both the amplitude and the phase pattern is demonstrated, and an algebraic decay associated with the mode order is measured. Notably, as opposed to a regular diffusion spreading, a self-similar contraction of a special subset of the solutions is predicted and observed.

O. Firstenberg; P. London; D. Yankelev; R. Pugatch; M. Shuker; N. Davidson

2010-08-16T23:59:59.000Z

150

Pipe diffusion at dislocations in UO2  

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

the fuel grain. Dislo- cations may also provide pathways for enhanced diffusion of fis- sion products, in particular, dislocations pinned to fission product precipitates may...

151

The Diffusion of GIS in Journalism.  

E-Print Network [OSTI]

??The purposes of this study were to determine the likelihood of reporters to adopt Geographical Information Systems and to predict the future of the diffusion… (more)

Wasike, Ben S.

2005-01-01T23:59:59.000Z

152

Diffuse Irradiance Study Planned for October  

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

installed at the SGP CART site near Lamont, Oklahoma. The instruments measuring diffuse solar radiation have black sphere-shaped shades to keep direct sunlight from reaching the...

153

ARM - Measurement - Shortwave narrowband diffuse downwelling...  

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

: Shortwave narrowband diffuse downwelling irradiance The rate at which radiant energy in narrow bands of wavelengths shorter than approximately 4 mum, that has been...

154

Independent Activity Report, Portsmouth Gaseous Diffusion Plant...  

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

2011 August 2011 Orientation Visit to the Portsmouth Gaseous Diffusion Plant HIAR-PORTS-2011-08-03 This Independent Activity Report documents an operational awareness...

155

Fully nonlinear equations for nonlocal diffusions  

E-Print Network [OSTI]

in collaboration with Luis Silvestre, we developed the parallel theory in the case of discontinuous (Levy type) diffusion. I plan to present the main steps.

2009-05-25T23:59:59.000Z

156

Mechanical memory  

DOE Patents [OSTI]

A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

Gilkey, Jeffrey C. (Albuquerque, NM); Duesterhaus, Michelle A. (Albuquerque, NM); Peter, Frank J. (Albuquerque, NM); Renn, Rosemarie A. (Albuquerque, NM); Baker, Michael S. (Albuquerque, NM)

2006-05-16T23:59:59.000Z

157

Mechanical memory  

DOE Patents [OSTI]

A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

Gilkey, Jeffrey C. (Albuquerque, NM); Duesterhaus, Michelle A. (Albuquerque, NM); Peter, Frank J. (Albuquerque, NM); Renn, Rosemarie A. (Alburquerque, NM); Baker, Michael S. (Albuquerque, NM)

2006-08-15T23:59:59.000Z

158

Laser-enhanced diffusion of nitrogen and aluminum dopants in silicon carbide  

Science Journals Connector (OSTI)

The diffusivities of different types of dopant atoms in silicon carbide wafers are generally very low. Nd:YAG and excimer lasers have been used to dope silicon carbide with nitrogen and aluminum, respectively. Mathematical models have been presented for the temperature distributions in the wafers to understand the diffusion mechanisms in the laser doping process. Since the silicon carbide substrate reaches its peritectic temperature (3100 K) at irradiances of 80.6 and 61 MW/cm2 for Nd:YAG and excimer lasers, respectively, lower irradiances were used to achieve solid-state diffusion. The Nd:YAG laser doping process doped nitrogen to a depth of 800 nm; the KrF excimer laser doping process produced aluminum dopant depths of 200 and 450 nm for different numbers of laser pulses. Two distinct diffusion regions, near-surface and far-surface regions, were identified in the dopant concentration profiles, indicating different diffusion mechanisms in these two regions. The effective diffusion coefficients of nitrogen and aluminum were determined for both regions and found to be 2.4 × 10?5 and 9.2 × 10?6 cm2/s in the near- and far-surface regions for nitrogen, respectively, and 1.2 × 10?5 and 1.3 × 10?6 cm2/s in the near- and far-surface regions for aluminum, respectively. The calculated diffusivities are at least six orders of magnitude higher than the typical values for nitrogen and aluminum, which indicate that the laser doping process enhances significantly the diffusion of dopants in silicon carbide.

Z. Tian; N.R. Quick; A. Kar

2006-01-01T23:59:59.000Z

159

Torsion Testing of Diffusion Bonded LIGA Formed Nickel  

SciTech Connect (OSTI)

A test technique has been devised which is suitable for the testing of the bond strength of batch diffusion bonded LIGA or DXRL defined structures. The method uses a torsion tester constructed with the aid of LIGA fabrication and distributed torsion specimens which also make use of the high aspect ratio nature of DXRL based processing. Measurements reveal achieved bond strengths of 130MPa between electroplated nickel with a bond temperature of 450 C at 7 ksi pressure which is a sufficiently low temperature to avoid mechanical strength degradation.

Buchheit, T.E.; Christenson, T.R.; Schmale, D.T.

1999-01-27T23:59:59.000Z

160

Thermal Particle Injection in Nonlinear Diffusive Shock Acceleration  

E-Print Network [OSTI]

Particle acceleration in collisionless astrophysical shocks, i.e., diffusive shock acceleration (DSA), is the most likely mechanism for producing cosmic rays, at least below 10^{15} eV. Despite the success of this theory, several key elements, including the injection of thermal particles, remains poorly understood. We investigate injection in strongly nonlinear shocks by comparing a semi-analytic model of DSA with a Monte Carlo model. These two models treat injection quite differently and we show, for a particular set of parameters, how these differences influence the overall acceleration efficiency and the shape of the broad-band distribution function.

Donald C. Ellison; Pasquale Blasi; Stefano Gabici

2005-07-05T23:59:59.000Z

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


161

Geothermal steam muffler diffusers: the Geysers, California. Failure analysis report  

SciTech Connect (OSTI)

The primary failure mechanism for the T304 diffusers was chloride induced stress corrosion cracking (sec.) Once SCC had progressed to a certain point, high cycle corrosion/fatigue proceeded to the final fracture. Alteration of the environment to prevent SCC is not feasible. The existing environment will also cause sulfide stress cracking (SSC) in susceptible materials; therefore, alternate materials must resist SSC as well as SCC. The very large amplitude operational stresses make heat treatment to relieve residual fabrication stress questionable for the prevention of SCC. (MHR)

McAlpin, R.; Ellis, P.F. II

1980-04-01T23:59:59.000Z

162

Modelling international wind energy diffusion: Are the patterns of induced diffusion `S'  

E-Print Network [OSTI]

Modelling international wind energy diffusion: Are the patterns of induced diffusion `S' shaped datasets, the paper explores the patterns of international wind energy diffusion in OECD countries. The model employed in the paper predicted that wind energy, as a complex and expensive innovation, would

Feigon, Brooke

163

Boron diffusion in nanocrystalline 3C-SiC  

SciTech Connect (OSTI)

The diffusion of boron in nanocrystalline silicon carbide (nc-SiC) films with a grain size of 4–7 nm is studied using a poly-Si boron source. Diffusion is found to be much faster than in monocrystalline SiC as it takes place within the grain boundary (GB) network. Drive-in temperatures of 900–1000°C are suitable for creating shallow boron profiles up to 100?nm deep, while 1100°C is sufficient to flood the 200?nm thick films with boron. From the resulting plateau at 1100?°C a boron segregation coefficient of 28 between nc-SiC and the Si substrate, as well as a GB boron solubility limit of 0.2?nm{sup ?2} is determined. GB diffusion in the bulk of the films is Fickian and thermally activated with D{sub GB}(T)=(3.1?5.6)×10{sup 7}exp(?5.03±0.16??eV/k{sub B}T) cm{sup 2}s{sup ?1}. The activation energy is interpreted in terms of a trapping mechanism at dangling bonds. Higher boron concentrations are present at the nc-SiC surface and are attributed to immobilized boron.

Schnabel, Manuel, E-mail: manuel.schnabel@ise.fraunhofer.de [Fraunhofer ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Department of Materials, University of Oxford, Parks Rd, Oxford OX1 3PH (United Kingdom); Weiss, Charlotte; Rachow, Thomas; Löper, Philipp; Janz, Stefan [Fraunhofer ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Canino, Mariaconcetta; Summonte, Caterina [CNR-IMM, Via Piero Gobetti 101, 40129 Bologna (Italy); Mirabella, Salvo [CNR-IMM MATIS, Via S. Sofia 64, 95123 Catania (Italy); Wilshaw, Peter R. [Department of Materials, University of Oxford, Parks Rd, Oxford OX1 3PH (United Kingdom)

2014-05-26T23:59:59.000Z

164

Antiproton Flux in Cosmic Ray Propagation Models with Anisotropic Diffusion  

E-Print Network [OSTI]

Recently a cosmic ray propagation model has been introduced, where anisotropic diffusion is used as a mechanism to allow for $\\mathcal{O}(100)$ km/s galactic winds. This model predicts a reduced antiproton background flux, suggesting an excess is being observed. We implement this model in GALPROP v50.1 and perform a $\\chi^2$ analysis for B/C, $^{10}$Be/$^{9}$Be, and the recent PAMELA $\\bar{p}/p$ datasets. By introducing a power-index parameter $\\alpha$ that dictates the dependence of the diffusion coefficient $D_{xx}$ on height $|z|$ away from the galactic plane, we confirm that isotropic diffusion models with $\\alpha=0$ cannot accommodate high velocity convective winds suggested by ROSAT, while models with $\\alpha=1$ ($D_{xx}\\propto |z|$) can give a very good fit. A fit to B/C and $^{10}$Be/$^{9}$Be data predicts a lower $\\bar{p}/p$ flux ratio than the PAMELA measurement at energies between approximately 2 GeV to 20 GeV. A combined fit including in addition the $\\bar{p}/p$ data is marginal, suggesting only a partial contribution to the measured antiproton flux.

Phillip Grajek; Kaoru Hagiwara

2010-12-02T23:59:59.000Z

165

Neoclassical diffusion in a turbulent plasma  

SciTech Connect (OSTI)

This work describes a new approach to plasma transport where the toroidal drift motion is considered as a perturbation to the fluctuating velocity. Percolation theory is used to determine the scaling of the diffusion coefficient. Several neoclassical phenomena should persist even when diffusion is enhanced from neoclassical predictions. Numerical simulation results support the theoretical scaling arguments.

Yushmanov, P. [Gosudarstvennyj Komitet po Ispol`zovaniyu Atomnoj Ehnergii SSSR, Moscow (USSR). Inst. Atomnoj Ehnergii]|[Texas Univ., Austin, TX (United States). Inst. for Fusion Studies

1991-11-01T23:59:59.000Z

166

ANISOTROPIC DIFFUSION USING POWER WATERSHEDS Camille Couprie  

E-Print Network [OSTI]

optimal methods such as graph cuts have received a lot of attention. However not all problems in com are able to optimize this energy quickly and effectively. This study paves the way for using the power and the diffusion time. Practical usage of anisotropic diffusion requires a choice between long compu- tation times

Paris-Sud XI, Université de

167

Numerical Early Warning Model Research of Landfill Gas Permeation and Diffusion Considering Flow-Temperature Coupling  

Science Journals Connector (OSTI)

Based on seepage mechanics in porous medium gas and heat transfer theory, numerical early warning model is established, which is on quantitative description of migration and release of landfill gas and penetration and diffusion of energy, and dynamic ... Keywords: component, landfill gas, flow-temperature coupling, gas pressure and temperature distribution, numerical early warning model

Xue Qiang; Feng Xia-ting; Ma Shi-jin; Zhou Xiao-jun

2009-10-01T23:59:59.000Z

168

Independent Oversight Review, Portsmouth Gaseous Diffusion Plant -  

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

Portsmouth Gaseous Diffusion Plant Portsmouth Gaseous Diffusion Plant - November 2013 Independent Oversight Review, Portsmouth Gaseous Diffusion Plant - November 2013 November 5, 2013 Review of Preparedness for Severe Natural Phenomena Events at the Portsmouth Gaseous Diffusion Plant This report documents the results of an independent oversight review of the preparedness of the DOE Portsmouth/Paducah Project Office, contractors at the DOE Portsmouth Gaseous Diffusion Plant, and selected non-leased facilities to respond to a severe natural phenomena event (NPE). The review was conducted in July and August 2013 by the U.S. Department of Energy's (DOE) Office of Safety and Emergency Management Evaluations, which is within the DOE Office of Health, Safety and Security (HSS). The HSS Office of Safety and Emergency Management Evaluations performed this

169

Nuclear diffuseness as a degree of freedom  

Science Journals Connector (OSTI)

The response of the nuclear energy to changes in neutron and proton surface diffusenesses is investigated using the Thomas-Fermi model. Algebraic expressions are provided for the energy cost of changing the two diffusenesses away from their equilibrium values. This will make it possible to generalize the macroscopic-microscopic calculations of nuclear masses and deformation energies by the inclusion of the neutron and proton diffusenesses as degrees of freedom (to be varied along with the shape degrees of freedom). One result, which is suggested by the relatively low cost in macroscopic energy of increasing the diffuseness of a heavy nucleus by 10% (about 4 MeV), is that superheavy nuclei near Z=126,?N=184 may have a fair chance of becoming stabilized by shell effects. An appendix introduces an improved measure of surface diffuseness, with certain advantages over the conventional Süssmann width b.

W. D. Myers and W. J. ?wia?tecki

1998-12-01T23:59:59.000Z

170

Computational mechanics  

SciTech Connect (OSTI)

The Computational Mechanics thrust area sponsors research into the underlying solid, structural and fluid mechanics and heat transfer necessary for the development of state-of-the-art general purpose computational software. The scale of computational capability spans office workstations, departmental computer servers, and Cray-class supercomputers. The DYNA, NIKE, and TOPAZ codes have achieved world fame through our broad collaborators program, in addition to their strong support of on-going Lawrence Livermore National Laboratory (LLNL) programs. Several technology transfer initiatives have been based on these established codes, teaming LLNL analysts and researchers with counterparts in industry, extending code capability to specific industrial interests of casting, metalforming, and automobile crash dynamics. The next-generation solid/structural mechanics code, ParaDyn, is targeted toward massively parallel computers, which will extend performance from gigaflop to teraflop power. Our work for FY-92 is described in the following eight articles: (1) Solution Strategies: New Approaches for Strongly Nonlinear Quasistatic Problems Using DYNA3D; (2) Enhanced Enforcement of Mechanical Contact: The Method of Augmented Lagrangians; (3) ParaDyn: New Generation Solid/Structural Mechanics Codes for Massively Parallel Processors; (4) Composite Damage Modeling; (5) HYDRA: A Parallel/Vector Flow Solver for Three-Dimensional, Transient, Incompressible Viscous How; (6) Development and Testing of the TRIM3D Radiation Heat Transfer Code; (7) A Methodology for Calculating the Seismic Response of Critical Structures; and (8) Reinforced Concrete Damage Modeling.

Goudreau, G.L.

1993-03-01T23:59:59.000Z

171

An observable for vacancy characterization and diffusion in crystals  

E-Print Network [OSTI]

To locate the position and characterize the dynamics of a vacancy in a crystal, we propose to represent it by the ground state density of a quantum probe quasi-particle for the Hamiltonian associated to the potential energy field generated by the atoms in the sample. In this description, the h^2/2mu coefficient of the kinetic energy term is a tunable parameter controlling the density localization in the regions of relevant minima of the potential energy field. Based on this description, we derive a set of collective variables that we use in rare event simulations to identify some of the vacancy diffusion paths in a 2D crystal. Our simulations reveal, in addition to the simple and expected nearest neighbor hopping path, a collective migration mechanism of the vacancy. This mechanism involves several lattice sites and produces a long range migration of the vacancy. Finally, we also observed a vacancy induced crystal reorientation process.

Pierre-Antoine Geslin; Giovanni Ciccotti; Eric Vanden-Eijnden; Simone Meloni

2012-11-20T23:59:59.000Z

172

Well testing model for multi-fractured horizontal well for shale gas reservoirs with consideration of dual diffusion in matrix  

Science Journals Connector (OSTI)

Abstract Shale gas reservoir is typical unconventional reservoir, it's necessary to take advantage of multi-stage fractured horizontal well so as to develop those kinds of reservoirs, which can form high conductivity hydraulic fractures and activate natural fractures. Due to the existence of concentration gap between matrix and fractures, desorption gas can simultaneously diffuse into the natural fractures and hydraulic fractures. This process can be called dual diffusion. Based on the triple-porosity cubic model, this paper establishes a new well testing model of multi-stage fractured horizontal well in shale gas reservoir with consideration of the unique mechanisms of desorption and dual diffusion in matrix. Laplace transformation is employed to solve this new model. The pseudo pressure transient responses are inverted into real time space with stehfest numerical inversion algorithm. Type curves are plotted, and different flow regimes in shale gas reservoirs are identified and the effects of relevant parameters are analyzed as well. Considering the mechanism of dual diffusion in matrix, the flow can be divided into five regimes: early linear flow; pseudo-steady state inter-porosity flow; the diffusion from matrix into micro-fractures; the diffusion from matrix into hydraulic fractures and boundary-dominated flow. There are large distinctions of pressure response between pseudo steady state diffusion and unsteady state diffusion under different value of pore volume ratio. It's similar to the feature of pseudo-steady state inter-porosity flow, diffusion coefficient and Langmuir parameters reflect the characters of pseudo-steady state diffusion. The numbers of stage of hydraulic fractures have certain impact on the shape factor of matrix and the inter-porosity coefficient. This new model is validated compared with some existing models. Finally, coupled with an application, this mew model can be approximately reliable and make some more precise productivity prediction.

Leng Tian; Cong Xiao; Mingjin Liu; Daihong Gu; Guangyu Song; Helong Cao; Xianglong Li

2014-01-01T23:59:59.000Z

173

Optoelectronic switches based on diffusive conduction Hilmi Volkan Demira  

E-Print Network [OSTI]

Optoelectronic switches based on diffusive conduction Hilmi Volkan Demira and Fatih Hakan Koklu the process of diffusive conduction that we use in our optoelectronic switches to achieve rapid optical. We demonstrate the feasibility of using such diffusive conductive optoelectronic switches

Miller, David A. B.

174

Mechanical Vibration  

Science Journals Connector (OSTI)

... THE suppression and control of mechanical vibration have assumed great importance in engineering. One consequence of this is that the number ... degree of emphasis is placed on transient oscillation (in addition to steady-State and free vibration). The treatment of this topic is based mainly on phase-plane constructions and it ...

R. E. D. BISHOP

1958-12-06T23:59:59.000Z

175

Heavy quark diffusion from the lattice  

SciTech Connect (OSTI)

We study the diffusion of heavy quarks in the quark gluon plasma using the Langevin equations of motion and estimate the contribution of the transport peak to the Euclidean current-current correlator. We show that the Euclidean correlator is remarkably insensitive to the heavy quark diffusion coefficient and give a physical interpretation of this result using the free streaming Boltzmann equation. However if the diffusion coefficient is smaller than {approx}1/({pi}T), as favored by RHIC phenomenology, the transport contribution should be visible in the Euclidean correlator. We outline a procedure to isolate this contribution.

Petreczky, Peter; Teaney, Derek [Nuclear Theory Group, Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States); Department of Physics and Astronomy, SUNY at Stony Brook, Stony Brook, New York 11764 (United States)

2006-01-01T23:59:59.000Z

176

Determinants of intranet diffusion and infusion  

Science Journals Connector (OSTI)

Commercial interest in Internet technology has grown tremendously in the last decade. Until now, little research has been devoted to examining the internal deployment of Internet technology. The present study focuses on the implementation process of intranets by examining factors associated with its diffusion and infusion in organizations. Findings suggest that earliness of adoption, top management support, and organizational size are positively associated with intranet diffusion. Intranet infusion is positively associated with earliness of adoption, top management support, and IT infrastructure flexibility, and these effects are mediated by intranet diffusion. Implications for management and suggestions for further research are discussed.

Lauren B. Eder; Magid Igbaria

2001-01-01T23:59:59.000Z

177

HINDERED DIFFUSION OF COAL LIQUIDS  

SciTech Connect (OSTI)

It was the purpose of the project described here to carry out careful and detailed investigations of petroleum and coal asphaltene transport through model porous systems under a broad range of temperature conditions. The experimental studies were to be coupled with detailed, in-depth statistical and molecular dynamics models intended to provide a fundamental understanding of the overall transport mechanisms and a more accurate concept of the asphaltene structure. The following discussion describes some of our accomplishments.

Theodore T. Tsotsis; Muhammad Sahimi; Ian A. Webster

1996-01-01T23:59:59.000Z

178

Mixing it up - Measuring diffusion in supercooled liquid solutions...  

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

Mixing it up - Measuring diffusion in supercooled liquid solutions of methanol and ethanol at temperatures near the glass Mixing it up - Measuring diffusion in supercooled liquid...

179

DOE - Office of Legacy Management -- Oak Ridge Gaseous Diffusion...  

Office of Legacy Management (LM)

Oak Ridge Gaseous Diffusion Plant - TN 02 FUSRAP Considered Sites Site: Oak Ridge Gaseous Diffusion Plant (TN.02 ) Designated Name: Alternate Name: Location: Evaluation Year: Site...

180

DOE - Office of Legacy Management -- Paducah Gaseous Diffusion...  

Office of Legacy Management (LM)

Paducah Gaseous Diffusion Plant - KY 01 FUSRAP Considered Sites Site: Paducah Gaseous Diffusion Plant (KY.01 ) Designated Name: Alternate Name: Location: Evaluation Year: Site...

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


181

Hydrogen diffusion in Lead Zirconate Titanate and Barium Titanate...  

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

diffusion in Lead Zirconate Titanate and Barium Titanate. Hydrogen diffusion in Lead Zirconate Titanate and Barium Titanate. Abstract: Hydrogen is a potential clean-burning,...

182

Non-Destructive Analysis Calibration Standards for Gaseous Diffusion...  

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

Non-Destructive Analysis Calibration Standards for Gaseous Diffusion Plant (GDP) Decommissioning Non-Destructive Analysis Calibration Standards for Gaseous Diffusion Plant (GDP)...

183

Oxygen Diffusion (OD) Dramatically Improves Wear-Resistance of...  

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

Oxygen Diffusion (OD) Dramatically Improves Wear-Resistance of Titanium Oxygen Diffusion (OD) Dramatically Improves Wear-Resistance of Titanium 2007 Diesel Engine-Efficiency &...

184

Using Rare Gas Permeation to Probe Methanol Diffusion near the...  

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

Rare Gas Permeation to Probe Methanol Diffusion near the Glass Transition Temperature. Using Rare Gas Permeation to Probe Methanol Diffusion near the Glass Transition Temperature....

185

HILO: Quasi Diffusion Accelerated Monte Carlo on Hybrid Architectures  

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

HILO: Quasi Diffusion Accelerated Monte Carlo on Hybrid Architectures HILO: Quasi Diffusion Accelerated Monte Carlo on Hybrid Architectures The Boltzmann transport equation...

186

ARM - Field Campaign - Diffuse Shortwave IOP  

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

govCampaignsDiffuse Shortwave IOP govCampaignsDiffuse Shortwave IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Diffuse Shortwave IOP 2001.09.24 - 2001.10.22 Lead Scientist : Joseph Michalsky Data Availability Data will not be available for public viewing until April 8, 2002. All data will be archived at the diffuse IOP web site by that date. For data sets, see below. Summary Almost 4 weeks of data were acquired under mostly sunny skies. Ninety-two percent of the daylight hours had measureable direct beam radiation. Much of the sunny data included completely cloud free conditions. The trackers functioned perfectly. Clear-sky data included low to moderate aerosol cases with no high aerosol conditions sampled. Data recovery from the

187

Diffuser Augmented Wind Turbine Analysis Code  

E-Print Network [OSTI]

, it is necessary to develop innovative wind capturing devices that can produce energy in the locations where large conventional horizontal axis wind turbines (HAWTs) are too impractical to install and operate. A diffuser augmented wind turbine (DAWT) is one...

Carroll, Jonathan

2014-05-31T23:59:59.000Z

188

Diffusion of Innovations over Multiplex Social Networks  

E-Print Network [OSTI]

The ways in which an innovation (e.g., new behaviour, idea, technology, product) diffuses among people can determine its success or failure. In this paper, we address the problem of diffusion of innovations over multiplex social networks where the neighbours of a person belong to one or multiple networks (or layers) such as friends, families, or colleagues. To this end, we generalise one of the basic game-theoretic diffusion models, called networked coordination game, for multiplex networks. We present analytical results for this extended model and validate them through a simulation study, finding among other properties a lower bound for the success of an innovation.While simple and leading to intuitively understandable results, to the best of our knowledge this is the first extension of a game-theoretic innovation diffusion model for multiplex networks and as such it provides a basic framework to study more sophisticated innovation dynamics.

Ramezanian, Rasoul; Magnani, Matteo; Montesi, Danilo

2014-01-01T23:59:59.000Z

189

Diffusion of innovations in social networks  

E-Print Network [OSTI]

While social networks do affect diffusion of innovations, the exact nature of these effects are far from clear, and, in many cases, there exist conflicting hypotheses among researchers. In this paper, we focus on the linear ...

Acemoglu, Daron

190

Diffusion of carbon dioxide (1); propane (2)  

Science Journals Connector (OSTI)

This document is part of Subvolume A ‘Gases in Gases, Liquids and their Mixtures’ of Volume 15 ‘Diffusion in Gases, Liquids and Electrolytes’ of Landolt-Börnstein Group IV ‘Physical Chemistry’. It is part of the ...

J. Winkelmann

2007-01-01T23:59:59.000Z

191

Diffusion of hydrogen (1); propane (2)  

Science Journals Connector (OSTI)

This document is part of Subvolume A ‘Gases in Gases, Liquids and their Mixtures’ of Volume 15 ‘Diffusion in Gases, Liquids and Electrolytes’ of Landolt-Börnstein Group IV ‘Physical Chemistry’. It is part of the ...

J. Winkelmann

2007-01-01T23:59:59.000Z

192

Diffusion Preconditioner for Discontinuous Galerkin Transport Problems  

E-Print Network [OSTI]

limits; however, it degrades for high-aspect ratio cells. These properties are typical for partially consistent diffusion synthetic acceleration (DSA) schemes, and in particular they are exactly the properties of the method that was previously developed...

Barbu, Anthony Petru

2011-08-08T23:59:59.000Z

193

Diffusion Databases for ICME | Department of Energy  

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

ICME Diffusion Databases for ICME 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation lm036warren2011o.pdf More...

194

Time-space fabric underlying anomalous diffusion  

E-Print Network [OSTI]

This study unveils the time-space transforms underlying anomalous diffusion process. Based on this finding, we present the two hypotheses concerning the effect of fractal time-space fabric on physical behaviors and accordingly derive fractional quantum relationships between energy and frequency, momentum and wavenumber which further give rise to fractional Schrodinger equation. As an alternative modeling approach to the standard fractional derivatives, we introduce the concept of the Hausdorff derivative underlying the Hausdorff dimensions of metric spacetime. And in terms of the proposed hypotheses, the Hausdorff derivative is used to derive a linear anomalous transport-diffusion equation underlying anomalous diffusion process. Its Green's function solution turns out to be a new type of stretched Gaussian distribution and is compared with that from the Richardson's diffusion equation.

W Chen

2005-05-08T23:59:59.000Z

195

Electrospray emitters For diffusion vacuum pumps  

E-Print Network [OSTI]

Following similar principles as regular diffusion vacuum pumps, an electrospray emitter is set to produce a jet of charged particles that will drag air molecules out of a volume. To be a feasible concept, the emitted ...

Diaz Gómez Maqueo, Pablo (Pablo Ly)

2011-01-01T23:59:59.000Z

196

Ising Model of Diffusion in Molecular Sieves  

Science Journals Connector (OSTI)

We have developed a new analytical theory for activated diffusion in zeolites at finite loadings, including the effect of adsorbate-adsorbate interactions. Excellent qualitative agreement is obtained comparing our new theory to kinetic Monte Carlo simulations. We have applied this theory to benzene diffusion in faujasite, to help resolve discrepancies among different experiments. Our results are in qualitative agreement with pulsed field gradient NMR, and in qualitative disagreement with tracer zero-length column data.

Chandra Saravanan; Fabien Jousse; Scott M. Auerbach

1998-06-29T23:59:59.000Z

197

Diffusive shielding stabilizes bulk nanobubble clusters  

E-Print Network [OSTI]

Using molecular dynamics, we study the nucleation and stability of bulk nanobubble clusters. We study the formation, growth, and final size of bulk nanobubbles. We find that, as long as the bubble-bubble interspacing is small enough, bulk nanobubbles are stable against dissolution. Simple diffusion calculations provide an excellent match with the simulation results, giving insight into the reason for the stability: nanobubbles in a cluster of bulk nanobubbles "protect" each other from diffusion by a shielding effect.

Weijs, Joost H; Lohse, D

2011-01-01T23:59:59.000Z

198

Independent Oversight Review, Portsmouth Gaseous Diffusion Plant – November 2013  

Broader source: Energy.gov [DOE]

Review of Preparedness for Severe Natural Phenomena Events at the Portsmouth Gaseous Diffusion Plant.

199

The diffusion of mobile telephones: An empirical analysis for Peru  

Science Journals Connector (OSTI)

This paper models the diffusion of mobile telephone subscriptions in Peru. Peru's mobile telephone diffusion has occurred in a concentrated market with relatively high prices and as such it features consumer behaviors such as call management, multiple ... Keywords: Diffusion forecasting, Gompertz curve, Mobile telephones, Peru, Technology diffusion

Peter Yamakawa; Gareth H. Rees; José Manuel Salas; Nikolai Alva

2013-07-01T23:59:59.000Z

200

Independent Oversight Review, Portsmouth Gaseous Diffusion Plant- January 2013  

Broader source: Energy.gov [DOE]

Review of the Portsmouth Gaseous Diffusion Plant Work Planning and Control Activities Prior to Work Execution

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


201

Fractal Location and Anomalous Diffusion Dynamics for Oil Wells from the KY Geological Survey  

E-Print Network [OSTI]

Utilizing data available from the Kentucky Geonet (KYGeonet.ky.gov) the fossil fuel mining locations created by the Kentucky Geological Survey geo-locating oil and gas wells are mapped using ESRI ArcGIS in Kentucky single plain 1602 ft projection. This data was then exported into a spreadsheet showing latitude and longitude for each point to be used for modeling at different scales to determine the fractal dimension of the set. Following the porosity and diffusivity studies of Tarafdar and Roy1 we extract fractal dimensions of the fossil fuel mining locations and search for evidence of scaling laws for the set of deposits. The Levy index is used to determine a match to a statistical mechanically motivated generalized probability function for the wells. This probability distribution corresponds to a solution of a dynamical anomalous diffusion equation of fractional order that describes the Levy paths which can be solved in the diffusion limit by the Fox H function ansatz.

Andrew, Keith; Andrew, Kevin A

2009-01-01T23:59:59.000Z

202

NUMERICAL MODELLING OF AUTOGENOUS HEALING AND RECOVERY OF MECHANICAL PROPERTIES IN ULTRA-HIGH  

E-Print Network [OSTI]

, hydro-chemo- mechanical coupling ABSTRACT Cracks, caused by shrinkage or external loading, reduce. In this study, a hydro-chemo-mechanical model was developed to simulate autogenous healing by further hydration into water was modelled based on micro-mechanical observations. The diffusion process has been simulated

Boyer, Edmond

203

Enforcement Letter, Geiger Brothers Mechanical Contractors, INC - March 26,  

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

Geiger Brothers Mechanical Contractors, INC - Geiger Brothers Mechanical Contractors, INC - March 26, 2010 Enforcement Letter, Geiger Brothers Mechanical Contractors, INC - March 26, 2010 March 26, 2010 Enforcement Letter issued to Geiger Brothers Mechanical Contractors, Inc. related to Installation and Inspection of Penetration Fire Seals at the DUF6 Conversion Building at the Portsmouth Gaseous Diffusion Plant This letter refers to the Office of Health, Safety and Security's Office of Enforcement investigation into the facts and circumstances associated with deficiencies in the installation and inspection of penetration fire seals at the DUF6 Conversion Building, located at the Portsmouth Gaseous Diffusion Plant. DOE's investigation report, dated January 22, 2009, was provided to Geiger Brothers Mechanical Contractors, Inc. (Geiger) under

204

Mechanical & Aerospace Engineering  

E-Print Network [OSTI]

Mechanical & Aerospace Engineering An experimental methodology is presented for mechanism verification of physics-based prognosis of mechanical damage, such as fatigue. The proposed experimental methodology includes multi-resolution in-situ mechanical testing, advanced imaging analysis, and mechanism

205

Activation Volume for Hf Diffusion in an Amorphous Ni0.54Zr0.46 Alloy  

Science Journals Connector (OSTI)

In this Letter we present the results of a diffusion study of Hf in a Ni0.54Zr0.46 amorphous alloy. We have measured the diffusion properties with and without pressure, up to 1 GPa. From these measurements we can deduce an Arrhenius behavior of the diffusion, with an activation energy of 0.76 eV and a pre-exponential factor of 7.4×10-17 m2/s. The activation volume amounts to 8.5 ?3. Activation volume and energy are related by the Keyes relationship. We then discuss to what extent presently proposed diffusion mechanisms, point defects, or collective processes can be tested against these results.

A. Grandjean; P. Blanchard; Y. Limoge

1997-01-27T23:59:59.000Z

206

ARM - Measurement - Shortwave spectral diffuse downwelling irradiance  

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

diffuse downwelling irradiance diffuse downwelling irradiance ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Shortwave spectral diffuse downwelling irradiance The rate at which spectrally resolved radiant energy at wavelengths shorter than approximately 4 {mu}m, that has been scattered in the atmosphere at least once, passes through a horizontal unit area in a downward direction. Categories Radiometric Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments RSS : Rotating Shadowband Spectroradiometer

207

ASYMMETRIC DIFFUSION OF MAGNETIC FIELD LINES  

SciTech Connect (OSTI)

Stochasticity of magnetic field lines is important for particle transport properties. Magnetic field lines separate faster than diffusively in turbulent plasma, which is called superdiffusion. We discovered that this superdiffusion is pronouncedly asymmetric, so that the separation of field lines along the magnetic field direction is different from the separation in the opposite direction. While the symmetry of the flow is broken by the so-called imbalance or cross-helicity, the difference between forward and backward diffusion is not directly due to imbalance, but a non-trivial consequence of both imbalance and non-reversibility of turbulence. The asymmetric diffusion perpendicular to the mean magnetic field entails a variety of new physical phenomena, such as the production of parallel particle streaming in the presence of perpendicular particle gradients. Such streaming and associated instabilities could be significant for particle transport in laboratory, space, and astrophysical plasmas.

Beresnyak, Andrey [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2013-04-20T23:59:59.000Z

208

Magnetoplasticity and diffusion in silicon single crystals  

SciTech Connect (OSTI)

The effect of static magnetic fields on the dynamics of surface dislocation segments, as well as the diffusion mobility of a dopant in silicon single crystals, has been analyzed. It has been experimentally found that the preliminary treatment of p-type silicon plates (the dopant is boron with a concentration of 10{sup 16} cm{sup -3}) in the static magnetic field (B = 1 T, a treatment time of 30 min) leads to an increase in the mobility of surface dislocation segments. The characteristic times of observed changes (about 80 h) and the threshold dopant concentration (10{sub 15} cm{sup -3}) below which the magneto-optical effect in silicon is not fixed have been determined. It has been found that diffusion processes in dislocation-free silicon are magnetically sensitive: the phosphorus diffusion depth in p-type silicon that is preliminarily aged in the static magnetic field increases (by approximately 20%) compared to the reference samples.

Skvortsov, A. A., E-mail: SkvortsovAA2009@yandex.ru; Karizin, A. V. [Moscow State Technical University 'MAMI' (Russian Federation)

2012-01-15T23:59:59.000Z

209

Single molecule tracking of heterogeneous diffusion  

Science Journals Connector (OSTI)

The mean square displacement of heterogeneous diffusion obeys the Einstein relation, thereby showing no sign of heterogeneities in the ensemble measurement of the diffusion constant. The signature of spatial heterogeneities appears in the time evolution of the non-Gaussian distribution and in the cross correlation between the square displacements at different times, both available from single molecule diffusional trajectories. As a quantitative measure, the non-Gaussian indicator g(t) decays asymptotically to zero according to 1/t for finite time correlation, but saturates at a plateau value for power-law correlation. In addition, the joint moment correlation function f(t,?) provides a direct probe of the memory effect of the fluctuating rate constant. A two-state diffusion model and a stochastic Gaussian model are constructed to evaluate these quantities and are shown to yield the same result within the second cumulant expansion.

Jianshu Cao

2001-03-16T23:59:59.000Z

210

ARM - Measurement - Shortwave broadband diffuse downwelling irradiance  

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

diffuse downwelling irradiance diffuse downwelling irradiance ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Shortwave broadband diffuse downwelling irradiance All of the solar radiation, across the wavelength range of 0.4 and 4 {mu}m, coming directly from the sky except for solar radiation coming directly from the sun and the circumsolar irradiance within approximately three degrees of the sun. Categories Radiometric Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments

211

Low-cost diffuse optical tomography for the classroom  

Science Journals Connector (OSTI)

Diffuse optical tomography (DOT) is an emerging imaging modality with potential applications in oncology neurology and other clinical areas. It allows the non-invasive probing of the tissue function using relatively inexpensive and safe instrumentation. An educational laboratory setup of a DOT system could be used to demonstrate how photons propagate through tissues basics of medical tomography and the concepts of multiple scattering and absorption. Here we report a DOT setup that could be introduced to the advanced undergraduate or early graduate curriculum using inexpensive and readily available tools. The basis of the system is the LEGO Mindstorms NXT platform which controls the light sources the detectors (photo-diodes) a mechanical 2D scanning platform and the data acquisition. A basic tomographic reconstruction is implemented in standard numerical software and 3D images are reconstructed. The concept was tested and developed in an educational environment that involved a high-school student and a group of post-doctoral fellows.

Taisuke Minagawa; Peyman Zirak; Udo M. Weigel; Anna K. Kristoffersen; Nicolas Mateos; Alejandra Valencia; Turgut Durduran

2012-01-01T23:59:59.000Z

212

Resistance Fluctuations Due to Hydrogen Diffusion in Niobium Thin Films  

Science Journals Connector (OSTI)

Fluctuations of the number of protons (H+) that scatter conduction electrons dominate lowfrequency resistance fluctuations in Nb films. The excess-noise spectra SV(f, T) obey a scaling law: fSV(f, T)??V2(T)?=g(fD(T)); for our geometry at 260diffusion coefficient is D(T)=D0e-EkT with D(300 K)?10-6 cm2/s and E?0.23 eV. Studies of 1f noise evoke comparable mechanisms.

John H. Scofield and Watt W. Webb

1985-01-28T23:59:59.000Z

213

Reducing industrial energy use with thermoelectric diffusion heat pumps  

SciTech Connect (OSTI)

The described Peltier Effect Diffusion System (PEDS) employs an innovative unit geometry in conjunction with thermoelectric (TE) heat pumps having high operational efficiency. Significant system design dynamics are explored, including heat and mass transfer mechanisms, fluid dynamics, and unit sizing methodology. Finally, estimated operating performance is presented for some representative industrial applications which are well suited to availability-based efficiency evaluations, namely: desalination, multi-stage absorption cycle refrigeration systems and freeze-concentration processes. Peltier effect TE heat pumps provide multi-stage work input to separations. The PEDS utilizes electrically generated heat as the separating agent, and pumps this energy to successively higher availability levels, resulting in high overall COP and greatly improved thermodynamic efficiency. Process costs in terms of availability utilization can be identified. The described PEDS process offers a meaningful alternative to conventional mass transfer methods.

Meckler, M.

1982-08-01T23:59:59.000Z

214

Comparison of Diffuse Shortwave Irradiance Measurements  

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

Diffuse Shortwave Diffuse Shortwave Irradiance Measurements J. J. Michalsky and J. Schlemmer Atmospheric Sciences Research Center State University of New York Albany, New York B. C. Bush, S. Leitner, D. Marsden, and F. P. J. Valero Scripps Institution of Oceanography University of California, San Diego La Jolla, California R. Dolce and A. Los Kipp & Zonen, Inc. Bohemia, New York and Delft The Netherlands E. G. Dutton Climate Monitoring and Diagnostics Laboratory National Oceanic and Atmospheric Administration Boulder, Colorado M. P. Haeffelin Virginia Polytechnic Institute and State University Blackburg, Virginia G. Major Budapest University of Economic Sciences and Public Administration Budapest, Hungry J. Hickey The Eppley Laboratory, Inc. Newport, Rhode Island

215

Self- and zinc diffusion in gallium antimonide  

SciTech Connect (OSTI)

The technological age has in large part been driven by the applications of semiconductors, and most notably by silicon. Our lives have been thoroughly changed by devices using the broad range of semiconductor technology developed over the past forty years. Much of the technological development has its foundation in research carried out on the different semiconductors whose properties can be exploited to make transistors, lasers, and many other devices. While the technological focus has largely been on silicon, many other semiconductor systems have applications in industry and offer formidable academic challenges. Diffusion studies belong to the most basic studies in semiconductors, important from both an application as well as research standpoint. Diffusion processes govern the junctions formed for device applications. As the device dimensions are decreased and the dopant concentrations increased, keeping pace with Moore's Law, a deeper understanding of diffusion is necessary to establish and maintain the sharp dopant profiles engineered for optimal device performance. From an academic viewpoint, diffusion in semiconductors allows for the study of point defects. Very few techniques exist which allow for the extraction of as much information of their properties. This study focuses on diffusion in the semiconductor gallium antimonide (GaSb). As will become clear, this compound semiconductor proves to be a powerful one for investigating both self- and foreign atom diffusion. While the results have direct applications for work on GaSb devices, the results should also be taken in the broader context of III-V semiconductors. Results here can be compared and contrasted to results in systems such as GaAs and even GaN, indicating trends within this common group of semiconductors. The results also have direct importance for ternary and quaternary semiconductor systems used in devices such as high speed InP/GaAsSb/InP double heterojunction bipolar transistors (DHBT) [Dvorak, (2001)]. Many of the findings which will be reported here were previously published in three journal articles. Hartmut Bracht was the lead author on two articles on self-diffusion studies in GaSb [Bracht, (2001), (2000)], while this report's author was the lead author on Zn diffusion results [Nicols, (2001)]. Much of the information contained herein can be found in those articles, but a more detailed treatment is presented here.

Nicols, Samuel Piers

2002-03-26T23:59:59.000Z

216

Zero-flux planes, flux reversals and diffusion paths in ternary and quaternary diffusion  

SciTech Connect (OSTI)

During isothermal multicomponent diffusion, interdiffusion fluxes of individual components can go to zero at zero-flux planes (ZFP) and exhibit flux reversals from one side to the other of such planes. Interdiffusion fluxes as well as the locations and compositions of ZFPs for components are determined directly from the concentration profiles of diffusion couples without the need for prior knowledge of interdiffusion coefficients. The development and identification of ZFPs is reviewed with the aid of single phase and two-phase diffusion couples investigated in the Cu-Ni-Zn system at 775/sup 0/C. ZFP locations in the diffusion zone nearly correspond to sections where the activity of a component is the same as its activity in either of the terminal alloys of a couple. Path slopes at ZFPs are uniquely dictated by the atomic mobility and thermodynamic data for the components. Discontinuous flux reversals for the components can also occur at interfaces in multiphase couples. Identification of ZFPs is also presented for diffusion in the Cu-Ni-Zn-Mn quaternary system. Analytical representation of diffusion paths for both ternary and quaternary diffusion couples is presented with the aid of characteristic path parameters.

Dayananda, M.A.

1986-05-23T23:59:59.000Z

217

Independent Activity Report, Portsmouth Gaseous Diffusion Plant - July 2011  

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

Activity Report, Portsmouth Gaseous Diffusion Plant - Activity Report, Portsmouth Gaseous Diffusion Plant - July 2011 Independent Activity Report, Portsmouth Gaseous Diffusion Plant - July 2011 July 2011 Orientation Visit to the Portsmouth Gaseous Diffusion Plant [HIAR-PAD-2011-07-27] The purpose of the visit was to discuss the nuclear safety oversight strategy, describe the site lead program, increase HSS personnel's operational awareness of the site's activities, and to determine how HSS can carry out its independent oversight and mission support responsibilities. Independent Activity Report, Portsmouth Gaseous Diffusion Plant - July 2011 More Documents & Publications Independent Activity Report, Portsmouth Gaseous Diffusion Plant - August 2011 Independent Activity Report, Argonne National Laboratory - August 2011

218

Open Source Software: Management, Diffusion and Competition  

E-Print Network [OSTI]

and competitive environment such as the ICT market. 1 Introduction OSS is an alternative model of software has introduced an innovative model of software development, based on self-organized communitiesOpen Source Software: Management, Diffusion and Competition Spyridoula Lakkaé National

Kouroupetroglou, Georgios

219

Correcting the diffusion approximation at the boundary  

E-Print Network [OSTI]

, 2011 The diffusion approximation to the radiative transport equation applies for light that has solutions of the radiative transport equation to evaluate each of their accuracy. Nonetheless, nearly all transport equation · I þ aI þ sLI ¼ 0; ð1:1� governs continuous light propagation in tissues [1

Kim, Arnold D.

220

Original article Mannitol enhances intracellular calcium diffusion  

E-Print Network [OSTI]

concentration-dependent increase in the amount of calcium absor- bed in 1 h from 8 cm long ileal loops prepared-enhanced movement of calcium out of the loop cannot have utilized the paracellular pathway, inasmuch as the luminalOriginal article Mannitol enhances intracellular calcium diffusion in the rat ileum ­ a hypothesis

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "vapor-phase diffusion mechanisms" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Mechanical and Aerospace Engineering  

E-Print Network [OSTI]

Mechanical and Aerospace Engineering seminar Three Dimensional Traction Force Microscopy with Applications in Cell Mechanics abstract The interactions between biochemical and mechanical signals during-dimensional measurement techniques are needed to investigate the effect of mechanical properties of the substrate

222

Mechanical Engineer Company Description  

E-Print Network [OSTI]

Mechanical Engineer Company Description Control Solutions Inc. is a small, dynamic, and rapidly. Position Description The Mechanical Engineer is responsible for all aspects associated with the mechanical enclosures, brackets, cabling assemblies among others. Systems include mechanisms, sensors, hydraulics, among

Kostic, Milivoje M.

223

MECHANICAL ENGINEERING Ross Schlueter  

E-Print Network [OSTI]

MECHANICAL ENGINEERING Ross Schlueter Engineering Deputy For Mechanical Engineering Russ Wells Mechanical Engineering Department Deputy ELECTRONICS, SOFTWARE & INSTRUMENTATION ENGINEERING Henrik von Der Sen Mechanical Admin. Assist. Joan Wolter Electronics Admin. Assist. Marilyn Wong Division Admin

224

Water Management in A PEMFC: Water Transport Mechanism and Material  

E-Print Network [OSTI]

Water Management in A PEMFC: Water Transport Mechanism and Material Degradation in Gas Diffusion on the water management of the PEMFC, namely the transport of product water (both liquid and vapor its water management performance and func- tion as indicators of the degradation of GDL material

Kandlikar, Satish

225

A stochastic mechanism of electron heating  

SciTech Connect (OSTI)

Due to Landau resonant interaction with lower hybrid waves in the lower hybrid current drive scheme part of electrons are accelerated and, as a result of this, a tail of energetic electrons is formed on the electron distribution function. The same situation takes place in the problem of type III radio bursts when the suprathermal burst electrons acquire a plateau distribution due to excitation of plasma waves in the solar wind plasma. These distributions are unstable with respect to the cyclotron excitation of waves at anomalous Doppler resonance ('fan' instability). In this case, the tail electrons interact simultaneously with both (i) waves that accelerate or decelerate them (Cerenkov resonance) and (ii) waves excited in the process of the fan instability that led to their pitch angle diffusion. Because velocity diffusion lines of electrons formed due to heir interaction with each type of waves intersect, this interaction can lead not only to pitch angle diffusion but also to heating of electrons mainly in perpendicular direction. We investigated this mechanism of electron heating and studied the temporal evolution of the electron temperature and the energy of excited waves. Our results show significant enhancement of the electron perpendicular temperature T{sub Up-Tack} due to this stochastic heating mechanism.

Galinsky, V. L.; Shevchenko, V. I. [University of California, San Diego, ECE Department, La Jolla, California 92093-0407 (United States)

2012-08-15T23:59:59.000Z

226

Ballistic vs. diffusive heat transfer across nanoscopic films of layered crystals  

SciTech Connect (OSTI)

We use non-equilibrium molecular dynamics to study the heat transfer mechanism across sandwich interfacial structures of Si/n-atomic-layers/Si, with 1???n???20 and atomic layers composed of WSe{sub 2} and/or graphene. In the case of WSe{sub 2} sheets, we observe that the thermal resistance of the sandwich structure is increasing almost linearly with the number of WSe{sub 2} sheets, n, indicating a diffusive phonon transport mechanism. By contrast in the case of n graphene layers, the interfacial thermal resistance is more or less independent on the number of layers for 1???n???10, and is associated with ballistic phonon transport mechanism. We attribute the diffusive heat transfer mechanism across WSe{sub 2} sheets to abundant low frequency and low group velocity optical modes that carry most of the heat across the interface. By contrast, in graphene, acoustic modes dominate the thermal transport across the interface and render a ballistic heat flow mechanism.

Shen, Meng; Keblinski, Pawel, E-mail: keblip@rpi.edu [Department of Materials Science and Engineering, and Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2014-04-14T23:59:59.000Z

227

Quantitative analysis of cerebral white matter anatomy from diffusion MRI  

E-Print Network [OSTI]

In this thesis we develop algorithms for quantitative analysis of white matter fiber tracts from diffusion MRI. The presented methods enable us to look at the variation of a diffusion measure along a fiber tract in a single ...

Maddah, Mahnaz

2008-01-01T23:59:59.000Z

228

Pattern formation in reaction diffusion systems: a Galerkin model  

Science Journals Connector (OSTI)

Reaction diffusion systems are extremely useful for studying pattern formation in biological systems. We carry out a Lorenz like few mode truncation of a reaction diffusion system and show that it not only giv...

A. Bhattacharyay; J.K. Bhattacharjee

2001-06-01T23:59:59.000Z

229

A Multiscale Framework for Markov Decision Processes using Diffusion Wavelets  

E-Print Network [OSTI]

A Multiscale Framework for Markov Decision Processes using Diffusion Wavelets Mauro Maggioni Program in Applied Mathematics Department of Mathematics Yale University New Haven, CT 06511 mauro Diffusion Wavelets Mauro Maggioni mauro.maggioni@yale.edu Program in Applied Mathematics Department

Mahadevan, Sridhar

230

On the Principle of Smooth Fit for Killed Diffusions  

E-Print Network [OSTI]

On the Principle of Smooth Fit for Killed Diffusions Farman Samee To appear in Electron. Commun of Smooth Fit for Killed Diffusions Farman Samee Research Report No. 16, 2006, Probab. Statist. Group

Sidorov, Nikita

231

CODED SPECTROSCOPY FOR ETHANOL DETECTION IN DIFFUSE, FLUORESCENT MEDIA  

E-Print Network [OSTI]

ABSTRACT CODED SPECTROSCOPY FOR ETHANOL DETECTION IN DIFFUSE, FLUORESCENT MEDIA by Scott Thomas Mc FOR ETHANOL DETECTION IN DIFFUSE, FLUORESCENT MEDIA by Scott Thomas McCain Department of Electrical

232

Sensitivity of climate change to diapycnal diffusivity in the ocean  

E-Print Network [OSTI]

The diapycnal diffusivity of the ocean is one of the least known parameters in cur- rent climate models. Measurements of this diffusivity are sparse and insufficient for compiling a global map. Inferences from inverse ...

Dalan, Fabio, 1975-

2003-01-01T23:59:59.000Z

233

Diffusion Multilayer Sampling of Ground Water in Five Wells at...  

Office of Environmental Management (EM)

Diffusion Multilayer Sampling of Ground Water in Five Wells at the Tuba City, Arizona, Site Diffusion Multilayer Sampling of Ground Water in Five Wells at the Tuba City, Arizona,...

234

Shell Model for Atomistic Simulation of Lithium Diffusion in...  

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

Shell Model for Atomistic Simulation of Lithium Diffusion in Mixed MnTi Oxides. Shell Model for Atomistic Simulation of Lithium Diffusion in Mixed MnTi Oxides. Abstract: Mixed...

235

A piecewise linear finite element discretization of the diffusion equation  

E-Print Network [OSTI]

it discretizes the diffusion equation on an arbitrary polyhedral mesh. We implemented our method in the KULL software package being developed at Lawrence Livermore National Laboratory. This code previously utilized Palmer's method as its diffusion solver, which...

Bailey, Teresa S

2006-10-30T23:59:59.000Z

236

Solar Energy Evolution and Diffusion Studies | Department of...  

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

Evolution and Diffusion Studies Solar Energy Evolution and Diffusion Studies Graphic of a map with pinpoints and a photo of a house with solar panels on the roof. Through the Solar...

237

Imaging Intrinsic Diffusion of Bridge-Bonded Oxygen Vacancies...  

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

Intrinsic Diffusion of Bridge-Bonded Oxygen Vacancies on TiO2(110). Imaging Intrinsic Diffusion of Bridge-Bonded Oxygen Vacancies on TiO2(110). Abstract: Since oxygen atom...

238

E-Print Network 3.0 - altered water diffusivity Sample Search...  

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

Emory University Collection: Materials Science ; Physics 47 Oxygen diffusion in titanite: Lattice diffusion and fast-path diffusion in single crystals Summary: , with little...

239

Independent Oversight Review, Portsmouth Gaseous Diffusion Plant- April 2013  

Broader source: Energy.gov [DOE]

Review of the Integrated Safety Management System Phase I Verification Review at the Portsmouth Gaseous Diffusion Plant

240

Nonlinear analysis of a reaction-diffusion system: Amplitude equations  

SciTech Connect (OSTI)

A reaction-diffusion system with a nonlinear diffusion term is considered. Based on nonlinear analysis, the amplitude equations are obtained in the cases of the Hopf and Turing instabilities in the system. Turing pattern-forming regions in the parameter space are determined for supercritical and subcritical instabilities in a two-component reaction-diffusion system.

Zemskov, E. P., E-mail: zemskov@ccas.ru [Russian Academy of Sciences, Dorodnicyn Computing Center (Russian Federation)

2012-10-15T23:59:59.000Z

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


241

ORIGINAL PAPER Assimilation and diffusion during xenolith-magma  

E-Print Network [OSTI]

(responsible for the linear mixing trends) and (2) diffusion-controlled redistribution of elements between bothORIGINAL PAPER Assimilation and diffusion during xenolith-magma interaction: a case study the assimilation of granitic melt. Linear mixing trends on Harker diagrams for most network-forming and mainly slow-diffusing

Podladchikov, Yuri

242

Gaseous Diffusion Plant Production Workers Needs Assessment  

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

Department of Energy Gaseous Diffusion Plants Department of Energy Gaseous Diffusion Plants Phase I: Needs Assessment Robert Wages Oil, Chemical and Atomic Inte national Union Steven Markowitz Mount Sinai School of Medicine Sylvia Kieding Oil, Chemical and Atomic International Union Mark Griffon University of Massachusetts Lowell Elizabeth Averill Samaras Alice Hamilton College October 1, 1997 TABLE OF CONTENTS Page Number Executive Summary 1 J: OVERVIEW 1. Introduction 2-3 2. Methods 3-8 3. Principal Findings 9-16 4. Need for Medical Surveillance and Risk Communication 16-17 PART II: METHODOLOGY AND RESULTS 4. Exposure Assessment Appendix A Appendix B Appendix C 5. Focus Group Results Appendix A Appendix B Appendix C 6. Epidemiology and Other Health Studies EXECUTIVE SUMMARY Purpose We report the results and analysis of a one year needs assessment study evaluating

243

Diffusion barriers in modified air brazes  

DOE Patents [OSTI]

A method for joining two ceramic parts, or a ceramic part and a metal part, and the joint formed thereby. The method provides two or more parts, a braze consisting of a mixture of copper oxide and silver, a diffusion barrier, and then heats the braze for a time and at a temperature sufficient to form the braze into a bond holding the two or more parts together. The diffusion barrier is an oxidizable metal that forms either a homogeneous component of the braze, a heterogeneous component of the braze, a separate layer bordering the braze, or combinations thereof. The oxidizable metal is selected from the group Al, Mg, Cr, Si, Ni, Co, Mn, Ti, Zr, Hf, Pt, Pd, Au, lanthanides, and combinations thereof.

Weil, Kenneth Scott; Hardy, John S; Kim, Jin Yong; Choi, Jung-Pyung

2013-04-23T23:59:59.000Z

244

Diffusion barriers in modified air brazes  

DOE Patents [OSTI]

A method for joining two ceramic parts, or a ceramic part and a metal part, and the joint formed thereby. The method provides two or more parts, a braze consisting of a mixture of copper oxide and silver, a diffusion barrier, and then heats the braze for a time and at a temperature sufficient to form the braze into a bond holding the two or more parts together. The diffusion barrier is an oxidizable metal that forms either a homogeneous component of the braze, a heterogeneous component of the braze, a separate layer bordering the braze, or combinations thereof. The oxidizable metal is selected from the group Al, Mg, Cr, Si, Ni, Co, Mn, Ti, Zr, Hf, Pt, Pd, Au, lanthanides, and combinations thereof.

Weil, Kenneth Scott (Richland, WA); Hardy, John S. (Richland, WA); Kim, Jin Yong (Richland, WA); Choi, Jung-Pyung (Richland, WA)

2010-04-06T23:59:59.000Z

245

Diffusive Acceleration of Ions at Interplanetary Shocks  

E-Print Network [OSTI]

Heliospheric shocks are excellent systems for testing theories of particle acceleration in their environs. These generally fall into two classes: (1) interplanetary shocks that are linear in their ion acceleration characteristics, with the non-thermal ions serving as test particles, and (2) non-linear systems such as the Earth's bow shock and the solar wind termination shock, where the accelerated ions strongly influence the magnetohydrodynamic structure of the shock. This paper explores the modelling of diffusive acceleration at a particular interplanetary shock, with an emphasis on explaining in situ measurements of ion distribution functions. The observational data for this event was acquired on day 292 of 1991 by the Ulysses mission. The modeling is performed using a well-known kinetic Monte Carlo simulation, which has yielded good agreement with observations at several heliospheric shocks, as have other theoretical techniques, namely hybrid plasma simulations, and numerical solution of the diffusion-conv...

Baring, M G; Baring, Matthew G.; Summerlin, Errol J.

2005-01-01T23:59:59.000Z

246

Waste acid recycling via diffusion dialysis  

SciTech Connect (OSTI)

Inorganic acids are commonly used for surface cleaning and finishing of metals. The acids become unuseable due to contamination with metals or diluted and weakened. Diffusion dialysis has become a way to recover the useable acid and allow separation of the metals for recovery and sale to refineries. This technique is made possible by the use of membranes that are strong enough to withstand low ph and have long service life.

Steffani, C.

1995-05-26T23:59:59.000Z

247

Diffuse-dynamic multiparameter diffractometry: A review  

SciTech Connect (OSTI)

The results reported at the Conference on Application of X-Rays, Synchrotron Radiation, Neutrons, and Electrons in Nano-, Bio-, Information-, and Cognitive Technologies (RSNE-NBIC 2009) are briefly reviewed. This review is based on a cycle of studies [1-6] where a new method for studying the structure of real crystals-diffuse-dynamic multiparameter diffractometry (DDMD)-was proposed and substantiated.

Molodkin, V. B., E-mail: molodkn@imp.kiev.ua; Shpak, A. P. [National Academy of Sciences of Ukraine, Institute of Metal Physics (Ukraine); Kovalchuk, M. V.; Nosik, V. L. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Machulin, V. F. [National Academy of Sciences of Ukraine, Institute of Semiconductor Physics (Ukraine)

2010-12-15T23:59:59.000Z

248

Distributed Energy Resources Market Diffusion Model  

SciTech Connect (OSTI)

Distributed generation (DG) technologies, such as gas-fired reciprocating engines and microturbines, have been found to be economically beneficial in meeting commercial-sector electrical, heating, and cooling loads. Even though the electric-only efficiency of DG is lower than that offered by traditional central stations, combined heat and power (CHP) applications using recovered heat can make the overall system energy efficiency of distributed energy resources (DER) greater. From a policy perspective, however, it would be useful to have good estimates of penetration rates of DER under various economic and regulatory scenarios. In order to examine the extent to which DER systems may be adopted at a national level, we model the diffusion of DER in the US commercial building sector under different technical research and technology outreach scenarios. In this context, technology market diffusion is assumed to depend on the system's economic attractiveness and the developer's knowledge about the technology. The latter can be spread both by word-of-mouth and by public outreach programs. To account for regional differences in energy markets and climates, as well as the economic potential for different building types, optimal DER systems are found for several building types and regions. Technology diffusion is then predicted via two scenarios: a baseline scenario and a program scenario, in which more research improves DER performance and stronger technology outreach programs increase DER knowledge. The results depict a large and diverse market where both optimal installed capacity and profitability vary significantly across regions and building types. According to the technology diffusion model, the West region will take the lead in DER installations mainly due to high electricity prices, followed by a later adoption in the Northeast and Midwest regions. Since the DER market is in an early stage, both technology research and outreach programs have the potential to increase DER adoption, and thus, shift building energy consumption to a more efficient alternative.

Maribu, Karl Magnus; Firestone, Ryan; Marnay, Chris; Siddiqui,Afzal S.

2006-06-16T23:59:59.000Z

249

Gas mixture for diffuse-discharge switch  

DOE Patents [OSTI]

Gaseous medium in a diffuse-discharge switch of a high-energy pulse generator is formed of argon combined with a compound selected from the group consisting of CF/sub 4/, C/sub 2/F/sub 6/, C/sub 3/F/sub 8/, n-C/sub 4/F/sub 10/, WF/sub 6/, (CF/sub 3/)/sub 2/S and (CF/sub 3/)/sub 2/O.

Christophorou, L.G.; Carter, J.G.; Hunter, S.R.

1982-08-31T23:59:59.000Z

250

Interactive Volume Rendering of Diffusion Tensor Data  

SciTech Connect (OSTI)

As 3D volumetric images of the human body become an increasingly crucial source of information for the diagnosis and treatment of a broad variety of medical conditions, advanced techniques that allow clinicians to efficiently and clearly visualize volumetric images become increasingly important. Interaction has proven to be a key concept in analysis of medical images because static images of 3D data are prone to artifacts and misunderstanding of depth. Furthermore, fading out clinically irrelevant aspects of the image while preserving contextual anatomical landmarks helps medical doctors to focus on important parts of the images without becoming disoriented. Our goal was to develop a tool that unifies interactive manipulation and context preserving visualization of medical images with a special focus on diffusion tensor imaging (DTI) data. At each image voxel, DTI provides a 3 x 3 tensor whose entries represent the 3D statistical properties of water diffusion locally. Water motion that is preferential to specific spatial directions suggests structural organization of the underlying biological tissue; in particular, in the human brain, the naturally occuring diffusion of water in the axon portion of neurons is predominantly anisotropic along the longitudinal direction of the elongated, fiber-like axons [MMM+02]. This property has made DTI an emerging source of information about the structural integrity of axons and axonal connectivity between brain regions, both of which are thought to be disrupted in a broad range of medical disorders including multiple sclerosis, cerebrovascular disease, and autism [Mos02, FCI+01, JLH+99, BGKM+04, BJB+03].

Hlawitschka, Mario; Weber, Gunther; Anwander, Alfred; Carmichael, Owen; Hamann, Bernd; Scheuermann, Gerik

2007-03-30T23:59:59.000Z

251

Diffuse-Charge Dynamics in Electrochemical Systems  

E-Print Network [OSTI]

The response of a model micro-electrochemical system to a time-dependent applied voltage is analyzed. The article begins with a fresh historical review including electrochemistry, colloidal science, and microfluidics. The model problem consists of a symmetric binary electrolyte between parallel-plate, blocking electrodes which suddenly apply a voltage. Compact Stern layers on the electrodes are also taken into account. The Nernst-Planck-Poisson equations are first linearized and solved by Laplace transforms for small voltages, and numerical solutions are obtained for large voltages. The ``weakly nonlinear'' limit of thin double layers is then analyzed by matched asymptotic expansions in the small parameter $\\epsilon = \\lambda_D/L$, where $\\lambda_D$ is the screening length and $L$ the electrode separation. At leading order, the system initially behaves like an RC circuit with a response time of $\\lambda_D L / D$ (not $\\lambda_D^2/D$), where $D$ is the ionic diffusivity, but nonlinearity violates this common picture and introduce multiple time scales. The charging process slows down, and neutral-salt adsorption by the diffuse part of the double layer couples to bulk diffusion at the time scale, $L^2/D$. In the ``strongly nonlinear'' regime (controlled by a dimensionless parameter resembling the Dukhin number), this effect produces bulk concentration gradients, and, at very large voltages, transient space charge. The article concludes with an overview of more general situations involving surface conduction, multi-component electrolytes, and Faradaic processes.

Martin Z. Bazant; Katsuyo Thornton; Armand Ajdari

2004-01-08T23:59:59.000Z

252

A diffuse interface model with immiscibility preservation  

SciTech Connect (OSTI)

A new, simple, and computationally efficient interface capturing scheme based on a diffuse interface approach is presented for simulation of compressible multiphase flows. Multi-fluid interfaces are represented using field variables (interface functions) with associated transport equations that are augmented, with respect to an established formulation, to enforce a selected interface thickness. The resulting interface region can be set just thick enough to be resolved by the underlying mesh and numerical method, yet thin enough to provide an efficient model for dynamics of well-resolved scales. A key advance in the present method is that the interface regularization is asymptotically compatible with the thermodynamic mixture laws of the mixture model upon which it is constructed. It incorporates first-order pressure and velocity non-equilibrium effects while preserving interface conditions for equilibrium flows, even within the thin diffused mixture region. We first quantify the improved convergence of this formulation in some widely used one-dimensional configurations, then show that it enables fundamentally better simulations of bubble dynamics. Demonstrations include both a spherical-bubble collapse, which is shown to maintain excellent symmetry despite the Cartesian mesh, and a jetting bubble collapse adjacent a wall. Comparisons show that without the new formulation the jet is suppressed by numerical diffusion leading to qualitatively incorrect results.

Tiwari, Arpit, E-mail: atiwari2@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)] [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Freund, Jonathan B., E-mail: jbfreund@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Pantano, Carlos [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)] [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

2013-11-01T23:59:59.000Z

253

Multicomponent Gas Diffusion in Porous Electrodes  

E-Print Network [OSTI]

Multicomponent gas transport is investigated with unprecedented precision by AC impedance analysis of porous YSZ anode-supported solid oxide fuel cells. A fuel gas mixture of H2-H2O-N2 is fed to the anode, and impedance data are measured across the range of hydrogen partial pressure (10-100%) for open circuit conditions at three temperatures (800C, 850C and 900C) and for 300mA applied current at 800C. For the first time, analytical formulae for the diffusion resistance (Rb) of three standard models of multicomponent gas transport (Fick, Stefan-Maxwell, and Dusty Gas) are derived and tested against the impedance data. The tortuosity is the only fitting parameter since all the diffusion coefficients are known. Only the Dusty Gas model leads to a remarkable data collapse for over twenty experimental conditions, using a constant tortuosity consistent with permeability measurements and the Bruggeman relation. These results establish the accuracy of the Dusty Gas model for multicomponent gas diffusion in porous med...

Fu, Yeqing; Dutta, Abhijit; Mohanram, Aravind; Pietras, John D; Bazant, Martin Z

2014-01-01T23:59:59.000Z

254

ENGINEERING MECHANICS SEMINARSENGINEERING MECHANICS SEMINARS THINK COMPOSITE  

E-Print Network [OSTI]

ENGINEERING MECHANICS SEMINARSENGINEERING MECHANICS SEMINARS THINK COMPOSITE "THINK outside the box" for more competitive structural COMPOSITES Dr. Melih Papila Visiting Professor, Aero/Astro Department, Stanford University. Adv. Composites and Polymer Processing Lab., Sabanci University, Istanbul. mpapila

Ponce, V. Miguel

255

Method and apparatus for maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling  

DOE Patents [OSTI]

An apparatus and method for diluting and cooling that is extracted from high temperature and/or high pressure industrial processes. Through a feedback process, a specialized, CFD-modeled dilution cooler is employed along with real-time estimations of the point at which condensation will occur within the dilution cooler to define a level of dilution and diluted gas temperature that results in a gas that can be conveyed to standard gas analyzers that contains no condensed hydrocarbon compounds or condensed moisture.

Farthing, William Earl (Pinson, AL) [Pinson, AL; Felix, Larry Gordon (Pelham, AL) [Pelham, AL; Snyder, Todd Robert (Birmingham, AL) [Birmingham, AL

2008-02-12T23:59:59.000Z

256

Method and apparatus maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling  

DOE Patents [OSTI]

An apparatus and method for diluting and cooling that is extracted from high temperature and/or high pressure industrial processes. Through a feedback process, a specialized, CFD-modeled dilution cooler is employed along with real-time estimations of the point at which condensation will occur within the dilution cooler to define a level of dilution and diluted gas temperature that results in a gas that can be conveyed to standard gas analyzers that contains no condensed hydrocarbon compounds or condensed moisture.

Farthing, William Earl (Pinson, AL); Felix, Larry Gordon (Pelham, AL); Snyder, Todd Robert (Birmingham, AL)

2009-12-15T23:59:59.000Z

257

Observation of photoluminescence from Al1 xInxN heteroepitaxial films grown by metalorganic vapor phase epitaxy  

E-Print Network [OSTI]

Observation of photoluminescence from Al1 xInxN heteroepitaxial films grown by metalorganic vapor have observed photoluminescence of Al1 xInxN films. The films were grown on GaN by atmospheric pressure-temperature deposited AlN buffer layer. Photoluminescence, absorption, and x-ray diffraction measurements have shown

Wetzel, Christian M.

258

Prevention of In droplets formation by HCl addition during metal organic vapor phase epitaxy of InN  

E-Print Network [OSTI]

for InN such as solar cells and infrared laser diodes. The growth of InN films must overcome several chal plasma-assisted15,16 and ArF excimer laser assisted MOVPE Ref. 17 has been demonstrated to avoid

Anderson, Timothy J.

259

Organometallic vapor-phase homoepitaxy of gallium arsenide assisted by a downstream hydrogen afterglow plasma in the growth region  

E-Print Network [OSTI]

of the trimeth- ylgallium (TMGa) for homoepitaxial GaAs. They found in direct comparison of the pure thermal-insulating) substrate is loaded into the depo- sition reactor of Fig. 1 without any chemical degreasing or polishing

Collins, George J.

260

Enhanced quality thin film Cu(In,Ga)Se.sub.2 for semiconductor device applications by vapor-phase recrystallization  

DOE Patents [OSTI]

Enhanced quality thin films of Cu.sub.w (In,Ga.sub.y)Se.sub.z for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu.sub.x Se on a substrate to form a large-grain precursor and then converting the excess Cu.sub.x Se to Cu(In,Ga)Se.sub.2 by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga).sub.y Se.sub.z. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300.degree.-600.degree. C., where the Cu(In,Ga)Se.sub.2 remains solid, while the excess Cu.sub.x Se is in a liquid flux. The characteristic of the resulting Cu.sub.w (In,Ga).sub.y Se.sub.z can be controlled by the temperature. Higher temperatures, such as 500.degree.-600.degree. C., result in a nearly stoichiometric Cu(In,Ga)Se.sub.2, whereas lower temperatures, such as 300.degree.-400.degree. C., result in a more Cu-poor compound, such as the Cu.sub.z (In,Ga).sub.4 Se.sub.7 phase.

Tuttle, John R. (Denver, CO); Contreras, Miguel A. (Golden, CO); Noufi, Rommel (Golden, CO); Albin, David S. (Denver, CO)

1994-01-01T23:59:59.000Z

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


261

Enhanced quality thin film Cu(In,Ga)Se[sub 2] for semiconductor device applications by vapor-phase recrystallization  

DOE Patents [OSTI]

Enhanced quality thin films of Cu[sub w](In,Ga[sub y])Se[sub z] for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu[sub x]Se on a substrate to form a large-grain precursor and then converting the excess Cu[sub x]Se to Cu(In,Ga)Se[sub 2] by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga)[sub y]Se[sub z]. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300--600 C, where the Cu(In,Ga)Se[sub 2] remains solid, while the excess Cu[sub x]Se is in a liquid flux. The characteristic of the resulting Cu[sub w](In,Ga)[sub y]Se[sub z] can be controlled by the temperature. Higher temperatures, such as 500--600 C, result in a nearly stoichiometric Cu(In,Ga)Se[sub 2], whereas lower temperatures, such as 300--400 C, result in a more Cu-poor compound, such as the Cu[sub z](In,Ga)[sub 4]Se[sub 7] phase. 7 figs.

Tuttle, J.R.; Contreras, M.A.; Noufi, R.; Albin, D.S.

1994-10-18T23:59:59.000Z

262

Quantitative Infrared Intensity Studies of Vapor-Phase Glyoxal, Methylglyoxal, and 2,3-Butanedione (Diacetyl) with Vibrational Assignments  

SciTech Connect (OSTI)

Glyoxal, methylglyoxal and 2,3-butanedione (diacetyl) are all known biomass burning effluents and suspected aerosol precursors. Pressure-broadened quantitative infrared spectra of glyoxal, methylglyoxal and diacetyl vapors covering the 520–6500 cm?1 range are reported at 0.11 cm?1 resolution, each with a composite spectrum derived from a minimum of ten different sample pressures for the compound, representing some of the first quantitative data for these analytes. The ordinate corresponds to a 1 meter optical pathlength and a mixing ratio of 1ppmv at 296 K. Many vibrational assignments for methylglyoxal are reported for the first time, as are some near-IR and far-IR bands of glyoxal and diacetyl. To complete the vibrational assignments, the quantitative far-infrared spectra (25 to 600 cm-1) of all three vapors are also reported, methylglyoxal for the first time. Density functional theory and ab initio MP2 theory are used to help assign vibrational modes. Potential bands useful for atmospheric monitoring are discussed.

Profeta, Luisa T.; Sams, Robert L.; Johnson, Timothy J.; Williams, Stephen D.

2011-09-08T23:59:59.000Z

263

Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride by metalorganic vapor-phase epitaxy  

E-Print Network [OSTI]

Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride to examine the effects of carbon tetrachloride concentration and temperature on the morphology of carbon with increasing carbon tetrachloride concentration. Step bunching and pinning was observed at a IV/III ratio

Li, Lian

264

Lattice Boltzmann modeling of multicomponent diffusion in narrow channels  

Science Journals Connector (OSTI)

We investigate lattice Boltzmann (LB) modeling of multicomponent diffusion for finite Knudsen numbers. Analytic solutions for binary diffusion in narrow channels, where both molecular and Knudsen diffusion are of importance, are obtained for the standard and higher-order LB methods and validated against the results from the direct simulation Monte Carlo (DSMC) method. The LB methods are shown to reproduce the diffusion slip phenomena. In the DSMC method, while fluid particles are diffusely reflected on a wall, significant component slip and a kinetic boundary layer are observed. It is shown that a higher-order LB method accurately captures the characteristics observed in the DSMC method.

Seung Hyun Kim; Heinz Pitsch; Iain D. Boyd

2009-01-08T23:59:59.000Z

265

Mutual diffusion in binary Ar-Kr mixtures and empirical diffusion models  

Science Journals Connector (OSTI)

Molecular dynamics simulations of four binary Ar-Kr mixtures are used to compute self- and mutual-diffusion coefficients. Results using mean squared displacements and using velocity correlation functions are presented. The diffusivity coefficients are also presented in the time and frequency domains where a comparatively low frequency structure is evident in some simulations. The computed diffusivities are dependent on the maximum time over which the velocity correlation functions are integrated and the time at which the Einstein relationships are evaluated. This dependence explains in part the small systematic differences between our results (20–80 ps) and earlier molecular dynamics results (<4 ps) in the system Ar-Kr. We compare the computed mutual diffusion coefficients to two empirical models, Darken’s model and the common force model. Darken’s model is consistent with our results over the entire frequency range we resolve. At frequencies lower than about 5 ps-1 Darken’s model and the common force model converge and we cannot discriminate between them. At higher frequencies the common force model prediction is significantly different from the computed mutual diffusion coefficient. Assumptions regarding the contribution of cross correlations that are implicit in the empirical models are discussed and tested against our simulation results. The net contribution of velocity cross correlations is found to be negligible, as is often assumed in deriving Darken’s model, but the individual cross-correlation terms are substantial and negative—a finding contrary to common assumptions. © 1996 The American Physical Society.

Yanhua Zhou and Gregory H. Miller

1996-02-01T23:59:59.000Z

266

Diffusion in single crystals of melilite: 2. Cations  

SciTech Connect (OSTI)

Diffusion coefficients of divalent cations, Ni, Co, Fe, Mn, Ca, Sr, and Ba, in synthetic akermanite were determined by tracer-diffusion experiments. Diffusion coefficients of cation paris, Al + Al-Mg + Si, Al + Al-Co + Si, and Mg-Co in melilite solid-solution systems, were determined by coupled annealing of synthetic melilites of endmember compositions. Cobalt tracer diffuses slower along the c-crystallographic axis than along the a-axis by a factor of about three, possibly due to the anisotropic sheet-like arrangement of oxygen ions parallel to the (001) plane which is perpendicular to the c-axis in the crystal structure of melilite. In the coupled diffusion experiments, the cation pairs interdiffuse complementary, as expected for conservation of material and ionic charge balance in the substitution. The observed trend in the inter-diffusion coefficient vs. melting temperature relations is similar to those observed for alloys and consistent with an empirical rule for self-diffusion coefficient-melting temperature relation. In the diffusion coefficient vs. ionic radius diagram for divalent cation diffusion in akermanite, smooth curves were observed as in the case of olivine systems. However, the shapes of the curves were significantly different from those observed in olivine systems. The observed trend of diffusion coefficients with ionic radius can be explained on the basis of crystal structure-controlled diffusion in akermanite.

Morioka, Masana (Univ. of Tokyo Yayoi (Japan)); Nagasawa, Hiroshi (Gakushiun Univ. Mejiro, Tokyo (Japan))

1991-03-01T23:59:59.000Z

267

Mechanical & Biomedical Engineering  

E-Print Network [OSTI]

Mechanical & Biomedical Engineering Department BACHELOR OF SCIENCE IN MECHANICAL ENGINEERING COURSE 105 Mechanical Engineering Graphics 3 CHEM 111L College Chemistry Lab (DLN) 1 ENGL 102 English PHYS 211 Mechanics, Waves & Heat (DLN) 4 UF 100 Intellectual Foundations 3 PHYS 211L Mechanics, Waves

Barrash, Warren

268

Mechanical Engineering Graduate Student  

E-Print Network [OSTI]

......................................................................................9 Engineering Career Services ................................................................9 McMechanical Engineering Graduate Student Handbook January 2014 Department of Mechanical Engineering University of Wisconsin-Madison #12;Mechanical Engineering Web Page: http://www.engr.wisc.edu/me Graduate

Wisconsin at Madison, University of

269

Mechanical & Industrial Engineering  

E-Print Network [OSTI]

Mechanical & Industrial Engineering 1 Welcome MIE Industrial Advisory Board October 15, 2010 #12;Mechanical & Industrial Engineering 2 MIE Dorothy Adams Undergraduate/Graduate Secretary David Schmidt Associate Professor & Graduate Program Director #12;Mechanical & Industrial Engineering 3 MIE James Rinderle

Mountziaris, T. J.

270

MECHANICAL ENGINEERING UNDERGRADUATE MAJOR  

E-Print Network [OSTI]

HANDBOOK FOR MECHANICAL ENGINEERING UNDERGRADUATE MAJOR Old Dominion University Department of Mechanical Engineering Batten College of Engineering and Technology Norfolk, Virginia 23529-0247 #12;TABLE OF CONTENTS MECHANICAL ENGINEERING HANDBOOK

271

Mechanical engineering Department Seminar  

E-Print Network [OSTI]

Mechanical engineering Department Seminar Katia Bertoldi Harvard University Soft materials in response to diverse stimuli. While the mechanical attributes - such as energy absorption, stiffness and switchable functionalities. Katia Bertoldi is an Assistant Professor of Applied Mechanics at Harvard

272

Electrophoretic Migration and Axial Diffusion of Individual Nanoparticles in Cylindrical Nanopores  

SciTech Connect (OSTI)

Membranes with straight, vertical nanopores have found widespread applications in chemical and biological sciences, including separation, detection, catalysis, and drug delivery. They can also serve as a model system to understand molecular behavior and fundamental mechanisms of separation, bridging the gap between conventional model systems such as flat surfaces and real chromatographic stationary phases such as micrometer-sized porous particles. We recently found that the axial motion of individual biomolecules inside nanopores can be significantly slower than in bulk solution. This suggests that either chromatographic adsorption was present and/or the viscosity inside the nanopores was unusually high. In this study, we measured the electrophoretic motion as well as the axial diffusion of individual nanoparticles in cylindrical alumina nanopores. We found that the electrophoretic mobilities and the diffusion coefficients of polystyrene nanoparticles were both substantially smaller compared to bulk solution independent of particle size or pore diameter. The results imply that the apparent solution viscosity in nanodomains is anomalous.

Han, Rui; Wang, Gufeng; Qi, Shengda; Ma, Changbei; Yeung, Edward S.

2012-08-01T23:59:59.000Z

273

Diffusion of Iodine and Rhenium in Category 3 Waste Encasement Concrete and Soil Fill Material  

SciTech Connect (OSTI)

Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e. sorption or precipitation). This understanding will enable accurate prediction of radionuclide fate when the waste forms come in contact with groundwater. A set of diffusion experiments using carbonated and non-carbonated concrete-soil half cells was conducted under unsaturated conditions (4% and 7% by wt moisture content). Spiked concrete half-cell specimens were prepared with and without colloidal metallic iron addition and were carbonated using supercritical carbon dioxide. Spikes of I and Re were added to achieve measurable diffusion profile in the soil part of the half-cell. In addition, properties of concrete materials likely to influence radionuclide migration such as carbonation were evaluated in an effort to correlate these properties with the release of iodine and rhenium.

Wellman, Dawn M.; Mattigod, Shas V.; Whyatt, Greg A.; Powers, Laura; Parker, Kent E.; Wood, Marcus I.

2006-12-15T23:59:59.000Z

274

Effect of exposure environment on surface decomposition of SiC–silver ion implantation diffusion couples  

Science Journals Connector (OSTI)

Abstract SiC is a promising material for nuclear applications and is a critical component in the construction of tristructural isotropic (TRISO) fuel. A primary issue with TRISO fuel operation is the observed release of 110mAg from intact fuel particles. The release of Ag has prompted research efforts to directly measure the transport mechanism of Ag in bulk SiC. Recent experimental efforts have focused primarily on Ag ion implantation designs. The effect of the thermal exposure system on the ion implantation surface has been investigated. Results indicate the utilization of a mated sample geometry and the establishment of a static thermal exposure environment is critical to maintaining an intact surface for diffusion analysis. The nature of the implantation surface and its potential role in Ag diffusion analysis are discussed.

Tyler J. Gerczak; Guiqiu Zheng; Kevin G. Field; Todd R. Allen

2015-01-01T23:59:59.000Z

275

Diffusion injected multi-quantum well light-emitting diode structure  

SciTech Connect (OSTI)

The attention towards light-emitting diode (LED) structures based on nanowires, surface plasmon coupled LEDs, and large-area high-power LEDs has been increasing for their potential in increasing the optical output power and efficiency of LEDs. In this work we demonstrate an alternative way to inject charge carriers into the active region of an LED, which is based on completely different current transport mechanism compared to conventional current injection approaches. The demonstrated structure is expected to help overcoming some of the challenges related to current injection with conventional structures. A functioning III-nitride diffusion injected light-emitting diode structure, in which the light-emitting active region is located outside the pn-junction, is realized and characterized. In this device design, the charge carriers are injected into the active region by bipolar diffusion, which could also be utilized to excite otherwise challenging to realize light-emitting structures.

Riuttanen, L., E-mail: lauri.riuttanen@aalto.fi; Nykänen, H.; Svensk, O.; Suihkonen, S.; Sopanen, M. [Department of Micro- and Nanosciences, Aalto University, P.O. Box 13500, FI-00076 Aalto (Finland); Kivisaari, P.; Oksanen, J.; Tulkki, J. [Department of Biomedical Engineering and Computational Science, Aalto University, P.O. Box 12200, FI-00076 Aalto (Finland)

2014-02-24T23:59:59.000Z

276

Monroe Thomas, Mechanical Technician  

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

Monroe Thomas, Mechanical Technician Print The weekend before the ALS was scheduled to start up again after the most recent shutdown, mechanical technician Monroe Thomas kept...

277

Direct Sampling Method for Diffusive Optical Tomography  

E-Print Network [OSTI]

In this work, we are concerned with the diffusive optical tomography (DOT) problem in the case when only one or two pairs of Cauchy data is available. We propose a simple and efficient direct sampling method (DSM) to locate inhomogeneities inside a homogeneous background and solve the DOT problem in both full and limited aperture cases. This new method is easy to implement and less expensive computationally. Numerical experiments demonstrate its effectiveness and robustness against noise in the data. This provides a new promising numerical strategy for the DOT problem.

Yat Tin Chow; Kazufumi Ito; Keji Liu; Jun Zou

2014-10-06T23:59:59.000Z

278

Theory of correlated hops in surface diffusion  

Science Journals Connector (OSTI)

Scanning tunneling microscopy observations of long hops in the diffusion of Pb atoms on Ge surfaces are explained by the model of a Brownian particle in a periodic potential. The classical turnover theory for barrier crossing predicts a large correlated hopping probability in the underdamped limit, consistent with experiment and in agreement with simulations. The corresponding quantum theory predicts that in the underdamped limit the rate is dominated by tunneling. This causes the quantum correlated hopping probability to vanish in this limit and may be thought of as a new form of quantum localization.

Eli Pollak, Joel Bader, B. J. Berne, and Peter Talkner

1993-05-24T23:59:59.000Z

279

Diffusion for an ensemble of Hamiltonians  

E-Print Network [OSTI]

Two ensembles of standard maps are studied analytically and numerically. In particular the diffusion coefficient is calculated. For one type of ensemble the chaotic parameter is chosen at random from a Gaussian distribution and is then kept fixed, while for the other type it varies from step to step. The effect of averaging out the details is evaluated and in particular it is found to be much more effective in the process of the second type. The work may shed light on the possible properties of different ensembles of mixed systems.

Or Alus; Shmuel Fishman

2014-09-17T23:59:59.000Z

280

Carbon Diffusion Across Dissimilar Steel Welds  

E-Print Network [OSTI]

of recrystallised ferrite. The major consequence of carbon diffusion is a loss of strength in the carbon depleted region and an increase in hardness in the carburised region. These zones are immediately adjacent to one another and provide a significant change... , tungsten and niobium, a sequence of alloy carbides may be formed, giving rise to the more complex M23C6 and M6C carbides at higher tempering temperatures. In this notation "M" indicates a mixture of metal atoms. Nutting (1969) summarises the sequence...

Race, Julia Margaret

1992-12-08T23:59:59.000Z

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


281

Results of tritium experiments on ceramic electrolysis cells and palladium diffusers for application to fusion reactor fuel cleanup systems  

SciTech Connect (OSTI)

Tritium tests at the Tritium Systems Test Assembly have demonstrated that ceramic electrolysis cells and palladium alloy diffuser developed in Japan are possible components for a fusion reactor fuel cleanup system. Both components have been successfully operated with tritium for over a year. A failure of the first electrolysis cell was most likely the result of an over voltage on the ceramic. A simple circuit was developed to eliminate this mode of failure. The palladium diffusers tubes exhibited some degradation of mechanical properties as a result of the build up of helium from the tritium decay, after 450 days of operation with tritium, however the effects were not significant enough to affect the performance. New models of the diffuser and electrolysis cell, providing higher flow rates and more tritium compatible designs are currently being tested with tritium. 8 refs., 5 figs.

Carlson, R.V.; Binning, K.E.; Konishi, S.; Yoshida, H.; Naruse, Y.

1987-01-01T23:59:59.000Z

282

Diffusion in single crystals of melilite: I. Oxygen  

SciTech Connect (OSTI)

Diffusion profiles of {sup 18}O tracer in single crystals of gehlenite and akermanite following annealing at 1,000{degree}-1,300{degree}C have been determined by a depth-profiling technique using secondary ion mass spectrometry. From the {sup 18}O depth profiling the lattice diffusion coefficients for oxygen along the crystallographic axes in gehlenite and akermanite, D{sup 1}{sub geh}//c, D{sup 1}{sub ak}//{alpha} and D{sup 1}{sub ak}//c, respectively, are given by three different equations. Present results are two to four orders of magnitude lower than those previously reported for melilite solid solutions. These high diffusion rates in melilite solid solutions and the heterogeneous distribution of O isotopes in the Allende Ca, Al-rich inclusions (CAIs) have been examined considering the contribution of fast diffusion along dislocations and possible changes in diffusion rate with gehlenite-akermanite ratios in melilite. For this purpose, diffusion coefficients of O along dislocations were calculated by analyzing tailing of the O-diffusion profiles. From the effective diffusion rate in melilite solid solution obtained by lattice and dislocation diffusion rates, it is unlikely that the O-isotope differences in the Allende CAI minerals are the result of diffusion processes during a postcrystallization thermal event.

Yurimoto, Hisayoshi (Univ. of Tsukuba, Ibaraki (Japan)); Morioka, Masana (Univ. of Tokyo (Japan)); Nagasawa, Hiroshi (Gakushuin Univ., Tokyo (Japan))

1989-09-01T23:59:59.000Z

283

On Similarities between Biological and Social Evolutionary Mechanisms: Mathematical Modeling  

E-Print Network [OSTI]

of widely diffused social innovation that enhances theof widely diffused social innovation that enhances the

Grinin, Leonid; Markov, Alexander; Korotayev, Andrey

2013-01-01T23:59:59.000Z

284

Chemical oxygen diffusion coefficient measurement by conductivity relaxation--correlation between tracer diffusion  

E-Print Network [OSTI]

Chemical oxygen diffusion coefficient measurement by conductivity relaxation--correlation between J. P., Grenier J. C., Loup J. P. ABSTRACT Chemical oxygen diusion coecient ¯(D)was measured the oxygen partial pressure in the surrounding atmosphere of the sample. The consequent evolution

Paris-Sud XI, Université de

285

Overview of SIMS-Based Experimental Studies of Tracer Diffusion in Solids and Application to Mg Self-Diffusion  

SciTech Connect (OSTI)

Tracer diffusivities provide the most fundamental information on diffusion in materials and are the foundation of robust diffusion databases. Compared to traditional radiotracer techniques that utilize radioactive isotopes, the secondary ion mass spectrometry (SIMS) based thin-film technique for tracer diffusion is based on the use of enriched stable isotopes that can be accurately profiled using SIMS. Experimental procedures & techniques that are utilized for the measurement of tracer diffusion coefficients are presented for pure magnesium, which presents some unique challenges due to the ease of oxidation. The development of a modified Shewmon-Rhines diffusion capsule for annealing Mg and an ultra-high vacuum (UHV) system for sputter deposition of Mg isotopes are discussed. Optimized conditions for accurate SIMS depth profiling in polycrystalline Mg are provided. An automated procedure for the correction of heat-up and cool-down times during tracer diffusion annealing is discussed. The non-linear fitting of a SIMS depth profile data using the thin film Gaussian solution to obtain the tracer diffusivity along with the background tracer concentration and tracer film thickness is discussed. An Arrhenius fit of the Mg self-diffusion data obtained using the low-temperature SIMS measurements from this study and the high-temperature radiotracer measurements of Shewmon and Rhines (1954) was found to be a good representation of both types of diffusion data that cover a broad range of temperatures between 250 - 627 C (523 900 K).

Kulkarni, Nagraj S [ORNL; Warmack, Robert J Bruce [ORNL; Radhakrishnan, Balasubramaniam [ORNL; HunterJr., Jerry [Virginia Polytechnic Institute and State University; Sohn, Yong Ho [University of Central Florida; Coffey, Kevin [University of Central Florida; Murch, Prof. Graeme [University of Newcastle, NSW, Australia; Belova, Irina [University of Newcastle, NSW, Australia

2014-01-01T23:59:59.000Z

286

Reaction and diffusion in turbulent combustion  

SciTech Connect (OSTI)

The motivation for this project is the need to obtain a better quantitative understanding of the technologically-important phenomenon of turbulent combustion. In nearly all applications in which fuel is burned-for example, fossil-fuel power plants, furnaces, gas-turbines and internal-combustion engines-the combustion takes place in a turbulent flow. Designers continually demand more quantitative information about this phenomenon-in the form of turbulent combustion models-so that they can design equipment with increased efficiency and decreased environmental impact. For some time the PI has been developing a class of turbulent combustion models known as PDF methods. These methods have the important virtue that both convection and reaction can be treated without turbulence-modelling assumptions. However, a mixing model is required to account for the effects of molecular diffusion. Currently, the available mixing models are known to have some significant defects. The major motivation of the project is to seek a better understanding of molecular diffusion in turbulent reactive flows, and hence to develop a better mixing model.

Pope, S.B. [Mechanical and Aerospace Engineering, Ithaca, NY (United States)

1993-12-01T23:59:59.000Z

287

Diffusive processes in a stochastic magnetic field  

Science Journals Connector (OSTI)

The statistical representation of a fluctuating (stochastic) magnetic field configuration is studied in detail. The Eulerian correlation functions of the magnetic field are determined, taking into account all geometrical constraints: these objects form a nondiagonal matrix. The Lagrangian correlations, within the reasonable Corrsin approximation, are reduced to a single scalar function, determined by an integral equation. The mean square perpendicular deviation of a geometrical point moving along a perturbed field line is determined by a nonlinear second-order differential equation. The separation of neighboring field lines in a stochastic magnetic field is studied. We find exponentiation lengths of both signs describing, in particular, a decay (on the average) of any initial anisotropy. The vanishing sum of these exponentiation lengths ensures the existence of an invariant which was overlooked in previous works. Next, the separation of a particle’s trajectory from the magnetic field line to which it was initially attached is studied by a similar method. Here too an initial phase of exponential separation appears. Assuming the existence of a final diffusive phase, anomalous diffusion coefficients are found for both weakly and strongly collisional limits. The latter is identical to the well known Rechester-Rosenbluth coefficient, which is obtained here by a more quantitative (though not entirely deductive) treatment than in earlier works.

Hai-Da Wang; M. Vlad; E. Vanden Eijnden; F. Spineanu; J. H. Misguich; R. Balescu

1995-05-01T23:59:59.000Z

288

Diffusion in biofilms respiring on electrodes  

SciTech Connect (OSTI)

The goal of this study was to measure spatially and temporally resolved effective diffusion coefficients (De) in biofilms respiring on electrodes. Two model electrochemically active biofilms, Geobacter sulfurreducens PCA and Shewanella oneidensis MR-1, were investigated. A novel nuclear magnetic resonance microimaging perfusion probe capable of simultaneous electrochemical and pulsed-field gradient nuclear magnetic resonance (PFG-NMR) techniques was used. PFG-NMR allowed for noninvasive, nondestructive, high spatial resolution in situ De measurements in living biofilms respiring on electrodes. The electrodes were polarized so that they would act as the sole terminal electron acceptor for microbial metabolism. We present our results as both two-dimensional De heat maps and surface-averaged relative effective diffusion coefficient (Drs) depth profiles. We found that (1) Drs decreases with depth in G. sulfurreducens biofilms, following a sigmoid shape; (2) Drs at a given location decreases with G. sulfurreducens biofilm age; (3) average De and Drs profiles in G. sulfurreducens biofilms are lower than those in S. oneidensis biofilms—the G. sulfurreducens biofilms studied here were on average 10 times denser than the S. oneidensis biofilms; and (4) halting the respiration of a G. sulfurreducens biofilm decreases the De values. Density, reflected by De, plays a major role in the extracellular electron transfer strategies of electrochemically active biofilms.

Renslow, Ryan S.; Babauta, Jerome T.; Majors, Paul D.; Beyenal, Haluk

2013-02-15T23:59:59.000Z

289

Distributed Wind Diffusion Model Overview (Presentation)  

SciTech Connect (OSTI)

Distributed wind market demand is driven by current and future wind price and performance, along with several non-price market factors like financing terms, retail electricity rates and rate structures, future wind incentives, and others. We developed a new distributed wind technology diffusion model for the contiguous United States that combines hourly wind speed data at 200m resolution with high resolution electricity load data for various consumer segments (e.g., residential, commercial, industrial), electricity rates and rate structures for utility service territories, incentive data, and high resolution tree cover. The model first calculates the economics of distributed wind at high spatial resolution for each market segment, and then uses a Bass diffusion framework to estimate the evolution of market demand over time. The model provides a fundamental new tool for characterizing how distributed wind market potential could be impacted by a range of future conditions, such as electricity price escalations, improvements in wind generator performance and installed cost, and new financing structures. This paper describes model methodology and presents sample results for distributed wind market potential in the contiguous U.S. through 2050.

Preus, R.; Drury, E.; Sigrin, B.; Gleason, M.

2014-07-01T23:59:59.000Z

290

Mechanical & Industrial Engineering  

E-Print Network [OSTI]

Mechanical & Industrial Engineering 1 Welcome MIE Industrial Advisory Board May 5th, 2011 #12;Mechanical & Industrial Engineering 2 IAB 2010-2011 · David K. Anderson ­ Alden Research Laboratory, Inc went on for three weeks Mechanical & Industrial Engineering 6 #12;Reza Shahbazian Yassar Mechanical

Mountziaris, T. J.

291

Career Map: Mechanical Engineer  

Broader source: Energy.gov [DOE]

The Wind Program's Career Map provides job description information for Mechanical Engineer positions.

292

Mechanical Engineering Undergraduate  

E-Print Network [OSTI]

Mechanical Engineering Department Undergraduate Advising Manual for Bachelor of Science Degrees in Mechanical Engineering and Engineering Mechanics 2011-2012 - Updated April 15, 2012 #12;Johns Hopkins University ­ Department of Mechanical Engineering 2011-2012 Undergraduate Student Advising Manual Page 2

Ghosh, Somnath

293

Mechanical engineering Department Seminar  

E-Print Network [OSTI]

Mechanical engineering Department Seminar James Bird Department of Mechanical Engineering Boston ­ are discussed. James Bird is an Assistant Professor in the Mechanical Engineering Department at Boston completed post-doctoral research at MIT. His research interests include experimental fluid mechanics

294

Mechanical Engineering Undergraduate  

E-Print Network [OSTI]

Mechanical Engineering Department Undergraduate Advising Manual for Bachelor of Science Degrees in Mechanical Engineering and Engineering Mechanics 2012-2013 - Updated July 14, 2013 #12;Johns Hopkins University ­ Department of Mechanical Engineering 2012-2013 Undergraduate Student Advising Manual Page 2

Ghosh, Somnath

295

Mechanical Engineering & Thermal Group  

E-Print Network [OSTI]

Mechanical Engineering & Thermal Group The Mechanical Engineering (ME) & Thermal Group at LASP has, and ground- based mechanical systems. Instrument Design Building on decades of design experience that has evolved with the complexity of instrument design demands, LASP mechanical engineers develop advanced

Mojzsis, Stephen J.

296

K-25 Gaseous Diffusion Process Building | Department of Energy  

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

Operational Management » History » Manhattan Project » Signature Operational Management » History » Manhattan Project » Signature Facilities » K-25 Gaseous Diffusion Process Building K-25 Gaseous Diffusion Process Building K-25 Gaseous Diffusion Process Building The K-25 plant, located on the southwestern end of the Oak Ridge reservation, used the gaseous diffusion method to separate uranium-235 from uranium-238. Based on the well-known principle that molecules of a lighter isotope would pass through a porous barrier more readily than molecules of a heavier one, gaseous diffusion produced through myriads of repetitions a gas increasingly rich in uranium-235 as the heavier uranium-238 was separated out in a system of cascades. Although producing minute amounts of final product measured in grams, gaseous diffusion required a massive

297

Narrow groove welding gas diffuser assembly and welding torch  

DOE Patents [OSTI]

A diffuser assembly is provided for narrow groove welding using an automatic gas tungsten arc welding torch. The diffuser assembly includes a manifold adapted for adjustable mounting on the welding torch which is received in a central opening in the manifold. Laterally extending manifold sections communicate with a shield gas inlet such that shield gas supplied to the inlet passes to gas passages of the manifold sections. First and second tapered diffusers are respectively connected to the manifold sections in fluid communication with the gas passages thereof. The diffusers extend downwardly along the torch electrode on opposite sides thereof so as to release shield gas along the length of the electrode and at the distal tip of the electrode. The diffusers are of a transverse width which is on the order of the thickness of the electrode so that the diffusers can, in use, be inserted into a narrow welding groove before and after the electrode in the direction of the weld operation.

Rooney, Stephen J. (East Berne, NY)

2001-01-01T23:59:59.000Z

298

Combined Quantum Mechanical and Molecular Mechanics Studies of...  

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

Mechanical and Molecular Mechanics Studies of the Electron-Transfer Reactions Involving Carbon Tetrachloride in Combined Quantum Mechanical and Molecular Mechanics Studies of the...

299

Effects of interface bonding and defects on boron diffusion at Si/SiO{sub 2} interface  

SciTech Connect (OSTI)

We perform first-principles density functional calculations to find the migration pathway and barrier for B diffusion at the Si/SiO{sub 2} interface. For various interface models, in which crystalline ?-quartz or amorphous silica (a-SiO{sub 2}) is placed on Si, we examine stable and metastable configurations of B-related defects which play a role in B diffusion. While a substitutional B alone is immobile in Si, it tends to diffuse to the interface via an interstitialcy mechanism in the presence of a self-interstitial and then changes into an interstitial B in oxide via a kick-out mechanism, leaving the self-interstitial at the interface. At the defect-free interface, where bridging O atoms are inserted to remove interface dangling bonds, an interstitial B prefers to intervene between the interface Si and bridging O atoms and subsequently diffuses through the hollow space or along the network of the Si-O-Si bonds in oxide. The overall migration barriers are calculated to be 2.02–2.12?eV at the Si/?-quartz interface, while they lie in the range of 2.04?±?0.44?eV at the Si/a-SiO{sub 2} interface, similar to that in ?-quartz. The migration pathway and barrier are not significantly affected by interface defects such as suboxide bond and O protrusion, while dangling bonds in the suboxide region can increase the migration barrier by about 1.5?eV. The result that the interface generally does not hinder the B diffusion from Si to SiO{sub 2} assists in understanding the underlying mechanism for B segregation which commonly occurs at the Si/SiO{sub 2} interface.

Kim, Geun-Myeong; Oh, Young Jun; Chang, K. J., E-mail: kchang@kaist.ac.kr [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)

2013-12-14T23:59:59.000Z

300

Non-Destructive Analysis Calibration Standards for Gaseous Diffusion Plant  

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

Non-Destructive Analysis Calibration Standards for Gaseous Non-Destructive Analysis Calibration Standards for Gaseous Diffusion Plant (GDP) Decommissioning Non-Destructive Analysis Calibration Standards for Gaseous Diffusion Plant (GDP) Decommissioning The decommissioning of Gaseous Diffusion Plant facilities requires accurate, non-destructive assay (NDA) of residual enriched uranium in facility components for safeguards and nuclear criticality safety purposes. Current practices used to perform NDA measurements frequently have poorly defined uncertainties due to multiple factors. Working reference material (WRM) standards and container-specific surrogates are required to verify and validate NDA methods used to support characterization of gaseous diffusion equipment within the D&D project. Because working reference

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


301

Optical waveguides in SBN by zinc vapor diffusion  

E-Print Network [OSTI]

at 600'C for a 12. 5 i1m Wide 1000'C Zinc Vapor Diffused SBN:60 Waveguide Measured at X = 0. 81 pm. IV. SBN:60 Amplitude Modulator Results . . . . . V. SBN:60 Mach-Zehnder Interferometer Results. . . . VI. Voltage-Length Product Comparison...: (a) extraordinary (TM), (b) 1. 5 x ordinary (TE). 12. Surface damage on SBN:60 diffused at 1000'C with an SiOz diffusion mask. 13. Zinc in-diffusion in SBN:60 25 . . . . . 26 . . . . . 27 . . . . . 28 29 14. Barium out-diffuison in SBN:60...

Quinn, Jeffrey Dale

1991-01-01T23:59:59.000Z

302

Binding and Diffusion of Lithium in Graphite: Quantum Monte Carlo...  

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

Binding and Diffusion of Lithium in Graphite: Quantum Monte Carlo Benchmarks and Validation of van der Waals Density Functional Methods P. Ganesh,* , Jeongnim Kim, Changwon...

303

A study of diffusion in binary solutions using spin echoes  

E-Print Network [OSTI]

Acetone 21 ~ 25 26 27 5 The Concentration Dependence of the Diffusion Coefficient of' Benzene in C6H6-CC1~ Solution Intrinsic 29 The Concentration Dependence of the Diffusion Coefficient of Benzene in C6H6-CS2 Solution Intrinsic a 30 ~ ~ 32... The Concentration Dependence of the Intrinsic Diffusion Coefficient of Cyclohexane in a C6H12 CC1~ Solution The Concentration Dependence of the Intrinsic Diffusion Coefficient of Cyclohexane in a C6H12-CS2 Solution LIST C1" TABLES Table Page Comparison...

Rousseau, Cecil Clyde

2012-06-07T23:59:59.000Z

304

Improved diffusion coefficients generated from Monte Carlo codes  

SciTech Connect (OSTI)

Monte Carlo codes are becoming more widely used for reactor analysis. Some of these applications involve the generation of diffusion theory parameters including macroscopic cross sections and diffusion coefficients. Two approximations used to generate diffusion coefficients are assessed using the Monte Carlo code MC21. The first is the method of homogenization; whether to weight either fine-group transport cross sections or fine-group diffusion coefficients when collapsing to few-group diffusion coefficients. The second is a fundamental approximation made to the energy-dependent P1 equations to derive the energy-dependent diffusion equations. Standard Monte Carlo codes usually generate a flux-weighted transport cross section with no correction to the diffusion approximation. Results indicate that this causes noticeable tilting in reconstructed pin powers in simple test lattices with L2 norm error of 3.6%. This error is reduced significantly to 0.27% when weighting fine-group diffusion coefficients by the flux and applying a correction to the diffusion approximation. Noticeable tilting in reconstructed fluxes and pin powers was reduced when applying these corrections. (authors)

Herman, B. R.; Forget, B.; Smith, K. [Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Aviles, B. N. [Knolls Atomic Power Laboratory, Bechtel Marine Propulsion Corporation, P.O. Box 1072, Schenectady, NY 12301-1072 (United States)

2013-07-01T23:59:59.000Z

305

Big Data Projects on Solar Technology Evolution and Diffusion...  

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

Projects on Solar Technology Evolution and Diffusion: Kickoff Meeting Graphic showing a web of people with energy bolts connecting them. Through the SEEDS program, seven projects...

306

Permeation and Diffusion of Hydrogen Through Pd Membranes  

SciTech Connect (OSTI)

Hydrogen diffusion through Pd membranes has been measured under non-UHV conditions, i.e., the membranes are evacuated under non-UHV conditions. Despite this, the results indicate that bulk diffusion is the slow step and the diffusion constants agree with earlier workers results where UHV conditions obtained. The activation energy for H2 permeation in the dilute phase was determined from an Arrhenius plot over a series of temperatures from 423 to 503 K. The solubilities of H2 were determined over the same temperature range and from these data, the diffusion constants were determined.

Shanahan, K.L.

2003-01-29T23:59:59.000Z

307

18.366 Random Walks and Diffusion, Spring 2005  

E-Print Network [OSTI]

Discrete and continuum modeling of diffusion processes in physics, chemistry, and economics. Topics include central limit theorems, continuous-time random walks, Levy flights, correlations, extreme events, mixing, ...

Bazant, Martin Z.

308

Optical processing furnace with quartz muffle and diffuser plate  

DOE Patents [OSTI]

An optical furnace for annealing a process wafer comprising a source of optical energy, a quartz muffle having a door to hold the wafer for processing, and a quartz diffuser plate to diffuse the light impinging on the quartz muffle; a feedback system with a light sensor located in the door or wall of the muffle is also provided for controlling the source of optical energy. The quartz for the diffuser plate is surface etched (to give the quartz diffusive qualities) in the furnace during a high intensity burn-in process.

Sopori, Bhushan L. (Denver, CO)

1995-01-01T23:59:59.000Z

309

Reduction in Fabrication Costs of Gas Diffusion Layers | Department...  

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

Layers Reduction in Fabrication Costs of Gas Diffusion Layers 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation...

310

Diffusion Databases for Mg-ICME | Department of Energy  

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

Mg-ICME Diffusion Databases for Mg-ICME 2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting...

311

X-ray Diffuse Scattering Measurements of Nucleation Dynamics...  

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

X-ray Diffuse Scattering Measurements of Nucleation Dynamics at Femtosecond Resolution Real-time measurement and control of the non-equilibrium properties of materials represents...

312

Energy Transport by Classical Waves through Multilayers of Diffusing Slabs  

Science Journals Connector (OSTI)

We describe the effect of interfaces on classical wave propagation through diffusing layered media. A series resistor model for wave energy transport is introduced and we derive a...

Gerritsen, Sijmen; Bauer, Gerrit E

313

Sandia National Laboratories: Mechanical Testing  

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

EnergyNuclear Energy Systems Laboratory (NESL) Brayton LabMechanical Testing Mechanical Testing Mechanical Testing Overview Mechanical 1-2 (2008). Standard Test Methods for...

314

[en] ASSESSMENT OF MOLECULAR DIFFUSION AS A MECHANISM FOR WAX DEPOSITION IN PETROLEUM PIPELINES.  

E-Print Network [OSTI]

??[pt] Deposição de parafinas, com alto peso molecular, na parede interna de linhas submarinas de produção e transporte continua a ser um problema crítico encontrado… (more)

MAO ILICH ROMERO VELASQUEZ

2006-01-01T23:59:59.000Z

315

Li ion diffusion mechanism in the crystalline electrolyte -Li3PO4  

E-Print Network [OSTI]

battery3 Solid state electrolyte could be made very thin to overcome to the low ion- conductivity et al., Solid State Ionics 53-56, 647 (1992). 3. http://www.ms.ornl.gov/researchgroups/Functional/BatteryV)material kTEA e T K T / )( - = 1. B. Wang et al., J. of Solid State Chemistry 115, 313 (1995). 2. J. B. Bates

Holzwarth, Natalie

316

Compaction Effects on Uniformity, Moisture Diffusion, and Mechanical Properties of Asphalt Pavements  

E-Print Network [OSTI]

Field compaction of asphalt mixtures is an important process that influences performance of asphalt pavements; however there is very little effort devoted to evaluate the influence of compaction on the uniformity and properties of asphalt mixtures...

Kassem, Emad Abdel-Rahman Ahmed

2011-08-08T23:59:59.000Z

317

NSLS Mechanical Tech  

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

Mechanical Tech Mechanical Tech The Mechanical Technician group is supervised by Robert Scheuerer and consists of Mechanical Technicians with fabrication/machining, assembly, installation, and alignment/surveying skills. This group also serves as an interface to Central Fabrication Services when more complex or larger fabrication efforts are needed. The Mechanical Tech group is responsible for fabricating, installing, aligning, and troubleshooting the mechanical hardware used on NSLS and SDL accelerators, front ends, and User beamlines, often starting solely from Mechanical Design group drawings or CAD files. The Mechanical Tech Group is responsible for the fabrication, assembly and installation of components at the NSLS. These components include all mechanical assemblies and RF cavities. Another part of their job is to

318

ARM - Measurement - Shortwave narrowband diffuse upwelling irradiance  

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

upwelling irradiance upwelling irradiance ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Shortwave narrowband diffuse upwelling irradiance The rate at which radiant energy in narrow bands of wavelengths shorter than approximately 4 {mu}m, that has been scattered in the atmosphere at least once, passes through a horizontal unit area in an upward direction. Categories Radiometric Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments MFR : Multifilter Radiometer

319

Turbulent diffusion with rotation or magnetic fields  

E-Print Network [OSTI]

The turbulent diffusion tensor describing the evolution of the mean concentration of a passive scalar is investigated for forced turbulence either in the presence of rotation or a magnetic field. With rotation the Coriolis force causes a sideways deflection of the flux of mean concentration. Within the magnetohydrodynamics approximation there is no analogous effect from the magnetic field because the effects on the flow do not depend on the sign of the field. Both rotation and magnetic fields tend to suppress turbulent transport, but this suppression is weaker in the direction along the magnetic field. Turbulent transport along the rotation axis is not strongly affected by rotation, except on shorter length scales, i.e. when the scale of the variation of the mean field becomes comparable with the scale of the energy-carrying eddied.

Brandenburg, Axel; Vasil, Geoffrey M

2009-01-01T23:59:59.000Z

320

Isothermally heatsunk diffusion cloud chamber refrigerator  

SciTech Connect (OSTI)

This patent describes a diffusion cloud chamber isothermally heatsunk refrigerator which comprises: a heatsink consisting of two phases of a saturated substance existing in thermodynamic equilibrium at constant pressure and therefore at constant temperature, contained in a reservoir; a means of pressure damping to maintain constant pressure, as the ratio of the two phases present changes and introduces volumetric changes in the substance; a cooling member which transfer heat from vapor in contact with the cooling member surface to the ''cold side'' of a Peltier thermoelectric element with which the cooling member is in thermal contact; a Peltier thermoelectric element which removes the heat supplied by the cooling member from its ''cold side'' and pumps it to the ''hot side'' when driven by an electric current; and a means of transferring heat from the ''hot side'' of the Peltier thermoelectric element to the two-phase isothermal substance in the reservoir.

Menocal, S.G.

1987-05-05T23:59:59.000Z

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


321

Diffusion of irreversible energy technologies under uncertainty  

SciTech Connect (OSTI)

This paper presents a model of technology diffusion is consistent with characteristics of participants in most energy markets. Whereas the models used most widely for empirical research are based on the assumption that the extended delays in adoption of cost-saving innovations are the result of either lack of knowledge about the new processes or heterogeneity across potential adopters, the model presented in this paper is based on the strategic behavior by firms. The strategic interdependence of the firms` decisions is rooted in spillover effects associated with an inability to exclude others from the learning-by-doing acquired when a firm implements a new technology. The model makes extensive use of recent developments in investment theory as it relates irreversible investments under uncertainty.

Cacallo, J.D.; Sutherland, R.J.

1993-09-01T23:59:59.000Z

322

Thermal diffusivity measurement system applied to polymers  

Science Journals Connector (OSTI)

In the search for cleaner energy sources the improvement of the efficiency of the actual ones appears as a primary objective. In this way thermoelectric materials which are able to convert wasted heat into electricity are reveal as an interesting way to improve efficiency of car engines for example. Cost-effective energy harvesting from thermoelectric devices requires materials with high electrical conductivities and Seebeck coefficient but low thermal conductivity. Conductive polymers can fulfil these conditions if they are doped appropriately. One of the most promising polymers is Polyaniline. In this work the thermal conductivity of the polyaniline and mixtures of polyaniline with nanoclays has been studied using a new experimental set-up developed in the lab. The novel system is based on the steady-state method and it is used to obtain the thermal diffusivity of the polymers and the nanocomposites.

2012-01-01T23:59:59.000Z

323

Microstructure and fracture toughness aspects of diffusion bonded interface between Ti and Al  

SciTech Connect (OSTI)

This study was undertaken to identify the microstructural characteristics of the intermetallic phases formed at the interface during the bonding process and determine the mechanical properties of Ti-Al dissimilar diffusion bonded joints, namely strength and fracture toughness. Furthermore, the effect of the intermetallic phases on the strength and fracture toughness of the joint was also determined. The effect of strength mis-match between Ti and Al on the fracture process will also be discussed. This investigation is the first phase of a larger project on the characterization of the intermetallics formed and their influence on strength and fracture toughness of the joints between TiAl-TiAl. A series of diffusion bonds of 25mm {times} 25 mm thick Ti bars were produced using aluminum foils of different thicknesses as interlayer. The bonded joints were tested to determine the fracture toughness properties of the interface formed and the effect of intermetallic phase formation on the fracture toughness was evaluated. Four-point bend specimens containing a crack introduced into the interface during the bonding process were tested to determine the diffusion-bonded interface fracture toughness. Tensile tests of the joints were also conducted to determine their strengths. The bonding conditions required to obtain a sound joint between Ti and Al were also evaluated.

Cam, G.; Dobi, D.; Kocak, M. [GKSS Research Center, Geesthacht (Germany); Heikinheimo, L.; Siren, M. [VTT Manufacturing Technology, Espoo (Finland)

1996-12-31T23:59:59.000Z

324

On the effect of gas diffusion layers hydrophobicity on direct methanol fuel cell performance and degradation  

Science Journals Connector (OSTI)

Abstract Degradation and mass transport phenomena management are two of the main issues hindering direct methanol fuel cell commercialization. Water and methanol crossover through the membrane, regulated by both anode and cathode gas diffusion layers hydrophobic properties, is widely studied in the literature, while the effect of mass transport phenomena evolution on the direct methanol fuel cell degradation has not been investigated yet. This work aims to present a combined experimental and modeling analysis on the effect of the gas diffusion layers hydrophobicity on DMFC degradation, through the comparison of performance characterization and degradation tests of two different fuel cells. In one of them, the lower diffusion layer hydrophobicity and the absence of anode microporous layer determines the onset of cathode flooding, negatively affecting performance and degradation. However, the cathode surface area loss is similar between the two fuel cells, meaning that flooding does not involve modifications in cathode permanent degradation mechanisms, but it mainly determines the amplification of the cathode surface area loss effects.

F. Bresciani; C. Rabissi; M. Zago; R. Marchesi; A. Casalegno

2015-01-01T23:59:59.000Z

325

Identification of As-vacancy complexes in Zn-diffused GaAs  

SciTech Connect (OSTI)

We have used positron annihilation spectroscopy to study the introduction of point defects in Zn-diffused semi-insulating GaAs. The diffusion was performed by annealing the samples for 2 h at 950 Degree-Sign C. The samples were etched in steps of 7 {mu}m. Both Doppler broadening using slow positron beam and lifetime spectroscopy studies were performed after each etching step. Both techniques showed the existence of vacancy-type defects in a layer of about 45 {mu}m. Secondary ion mass spectroscopy measurements illustrated the presence of Zn at high level in the sample almost up to the same depth. Vacancy-like defects as well as shallow positron traps were observed by lifetime measurements. We distinguish two kinds of defects: As vacancy belongs to defect complex, bound to most likely one Zn atom incorporated on Ga sublattice, and negative-ion-type positron traps. Zn acceptors explained the observation of shallow traps. The effect of Zn was evidenced by probing GaAs samples annealed under similar conditions but without Zn treatment. A defect-free bulk lifetime value is detected in this sample. Moreover, our positron annihilation spectroscopy measurements demonstrate that Zn diffusion in GaAs system is governed by kick-out mechanism.

Elsayed, M. [Department of Physics, Martin Luther University Halle, 06099 Halle (Germany); Department of Physics, Faculty of Science, Minia University, 61519 Minia (Egypt); Krause-Rehberg, R. [Department of Physics, Martin Luther University Halle, 06099 Halle (Germany); Korff, B. [Bremen Center for Computational Materials Science, University Bremen, 28359 Bremen (Germany); Richter, S. [Fraunhofer Center for Silicon Photovoltaics CSP, 06120 Halle (Saale) (Germany); Leipner, H. S. [Center of Materials Science, Martin Luther University Halle, 06099 Halle (Germany)

2013-03-07T23:59:59.000Z

326

Strain effect on the adsorption, diffusion, and molecular dissociation of hydrogen on Mg (0001) surface  

SciTech Connect (OSTI)

The adsorption, diffusion, and molecular dissociation of hydrogen on the biaxially strained Mg (0001) surface have been systematically investigated by the first principle calculations based on density functional theory. When the strain changes from the compressive to tensile state, the adsorption energy of H atom linearly increases while its diffusion barrier linearly decreases oppositely. The dissociation barrier of H{sub 2} molecule linearly reduces in the tensile strain region. Through the chemical bonding analysis including the charge density difference, the projected density of states and the Mulliken population, the mechanism of the strain effect on the adsorption of H atom and the dissociation of H{sub 2} molecule has been elucidated by an s-p charge transfer model. With the reduction of the orbital overlap between the surface Mg atoms upon the lattice expansion, the charge transfers from p to s states of Mg atoms, which enhances the hybridization of H s and Mg s orbitals. Therefore, the bonding interaction of H with Mg surface is strengthened and then the atomic diffusion and molecular dissociation barriers of hydrogen decrease accordingly. Our works will be helpful to understand and to estimate the influence of the lattice deformation on the performance of Mg-containing hydrogen storage materials.

Lei, Huaping; Wang, Caizhuang; Yao, Yongxin; Hupalo, Myron [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States)] [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States); Wang, Yangang [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States) [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States); Supercomputing Center of Computer Network Information Center, CAS, Beijing 100190 (China); McDougall, Dan; Tringides, Michael; Ho, Kaiming [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States) [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

2013-12-14T23:59:59.000Z

327

Bulk diffusion induced structural modifications of carbon-transition metal nanocomposite films  

SciTech Connect (OSTI)

The influence of transition metal (TM = V,Co,Cu) type on the bulk diffusion induced structural changes in carbon:TM nanocomposite films is investigated. The TMs have been incorporated into the carbon matrix via ion beam co-sputtering, and subsequently the films have been vacuum annealed in the temperature range of 300 - 700 deg. C. The structure of both the dispersed metal rich and the carbon matrix phases has been determined by a combination of elastic recoil detection analysis, x-ray diffraction, transmission electron microscopy, and Raman spectroscopy. The as-grown films consist of carbidic (V and Co) and metallic (Cu) nanoparticles dispersed in the carbon matrix. Thermal annealing induces surface segregation of Co and Cu starting at {>=} 500 deg. C, preceded by the carbide-metal transformation of Co-carbide nanoparticles at {approx} 300 deg. C. No considerable morphological changes occur in C:V films. In contrast to the surface diffusion dominated regime where all the metals enhance the six-fold ring clustering of C, in the bulk diffusion controlled regime only Co acts as a catalyst for the carbon graphitization. These results are consistent with the metal-induced crystallization mechanism in the C:Co films. The results are discussed on the basis of the metal-carbide phase stability, carbon solubility in metals or their carbides, and interface species.

Berndt, M.; Abrasonis, G.; Kovacs, Gy. J.; Krause, M.; Munnik, F.; Heller, R.; Kolitsch, A.; Moeller, W.

2011-03-15T23:59:59.000Z

328

Uniformly Accurate Diffusive Relaxation Schemes for Multiscale Transport Equations  

E-Print Network [OSTI]

, radiative transfer, and transport equations for waves in random media, have a diffusive scaling that leads #12; 1. Introduction Many transport equations, such as the neutron transport [CZ], radiative transferUniformly Accurate Diffusive Relaxation Schemes for Multiscale Transport Equations Shi JIN y

329

Diffusion MRI of Complex Tissue Structure David Solomon Tuch  

E-Print Network [OSTI]

Diffusion MRI of Complex Tissue Structure by David Solomon Tuch B.A., Physics, University Solomon Tuch Submitted to the Division of Health Sciences and Technology on January 11, 2002, in partial to be beyond the scope of diffusion imaging methodology. Thesis Supervisor: Van Jay Wedeen Title: Associate

Duncan, James S.

330

Comment on "Optimal Reaction Time for Surface-Mediated Diffusion"  

E-Print Network [OSTI]

In recent letter [Phys. Rev. Lett {\\bf 105}, 150606 (2010)], the surface-mediated diffusion problem is theoretically discussed, and interesting results have been obtained. However, for more general cases, the ansatz of solutions of the diffusion equation, which is the starting point of their analysis, might not be appropriate. In this comment, suggested ansatz and corresponding methods will be presented.

Yunxin Zhang

2011-03-04T23:59:59.000Z

331

Experimental and numerical investigation of microscale hydrogen diffusion flames  

E-Print Network [OSTI]

are properly modeled. However, the code does not properly predict the air entrainment and pre-heating enhanced thermal-diffusive effects. Therefore, thermal diffusion for light species and different combustion models of time of operation. Generally, the energy density of typical hydrocarbon fuels is about 100 times higher

Leu, Tzong-Shyng "Jeremy"

332

Optical processing furnace with quartz muffle and diffuser plate  

DOE Patents [OSTI]

An optical furnace for annealing a process wafer comprising a source of optical energy, a quartz muffle having a door to hold the wafer for processing, and a quartz diffuser plate to diffuse the light impinging on the quartz muffle; a feedback system with a light sensor located in the wall of the muffle is also provided for controlling the source of optical energy.

Sopori, Bhushan L. (Denver, CO)

1996-01-01T23:59:59.000Z

333

Interactive visual simulation of dynamic ink diffusion effects  

Science Journals Connector (OSTI)

This paper presents an effective method that simulates the ink diffusion process with visual plausible effects and real-time performance. Our algorithm updates the dynamic ink volume with a hybrid grid-particle representation: the fluid velocity field ... Keywords: industrial animation, ink diffusion, interaction, motion blur

Shibiao Xu; Xing Mei; Weiming Dong; Zhiyi Zhang; Xiaopeng Zhang

2011-12-01T23:59:59.000Z

334

Experimental determination of the boundary condition for diffuse photons  

E-Print Network [OSTI]

of a turbid medium, the light transport is described by the diffusion approxima- tion of the radiative of a turbid medium within a few transport mean free paths, the diffusion equation is no longer satisfied light transport through a turbid (i.e., highly scatter- ing) medium and in imaging objects

Zhu, Xiangdong

335

Diffusion in Nanoporous Phases:? Size Dependence and Levitation Effect  

Science Journals Connector (OSTI)

Diffusion of guests, xenon and argon, in two zeolites with different bottleneck diameters show a surprising dependence of self-diffusivity on the guest diameter. ... Note oscillation in ??(k)/2Dk2 near k = 0.5 Å-1 for the guest from LR. ... The oscillations are not large on the ordinate suggesting that the slow down in motion is not significant. ...

S. Yashonath; Pradip Kr. Ghorai

2007-12-18T23:59:59.000Z

336

1st workshop on diffusion networks and cascade analytics  

Science Journals Connector (OSTI)

Diffusion and cascades have been studied for many years in sociology, and different theoretical models have been developed. However, experimental validation has been always carried out in relatively small datasets. In recent years, with the availability ... Keywords: cascade modeling, diffusion networks

Peng Cui; Fei Wang; Hanghang Tong; Manuel Gomez Rodriguez

2014-02-01T23:59:59.000Z

337

Photonic bandgaps of periodic multilayers with diffuse interfaces  

E-Print Network [OSTI]

of the locations and widths of the forbidden bandgaps is standard [1­3]. However, generally the interfaces betweenPhotonic bandgaps of periodic multilayers with diffuse interfaces Jean-Michel André* , Philippe-michel.andre1@upmc.fr The photonic bandgap of periodic multilayers with diffuse interface is calculated

Boyer, Edmond

338

Peer Effects in the Diffusion of Solar Photovoltaic Panels  

Science Journals Connector (OSTI)

Social interaction (peer) effects are recognized as a potentially important factor in the diffusion of new products. In the case of environmentally friendly goods or technologies, both marketers and policy makers are interested in the presence of causal ... Keywords: diffusion models, empirical IO methods, endogeneity, probability models, social contagion, word of mouth

Bryan Bollinger; Kenneth Gillingham

2012-11-01T23:59:59.000Z

339

Peer Effects in the Diffusion of Solar Photovoltaic Panels  

E-Print Network [OSTI]

Peer Effects in the Diffusion of Solar Photovoltaic Panels Bryan Bollinger NYU Stern School base of consumers in the reference group. We study the diffusion of solar photovoltaic panels of an environmentally beneficial technology, solar photovoltaic (PV) panels. Policymakers are particularly interested

Lee, Daeyeol

340

Vacancy mediated substitutional diffusion in binary crystalline solids  

E-Print Network [OSTI]

Vacancy mediated substitutional diffusion in binary crystalline solids Anton Van der Ven a,*, Hui coefficients of substi- tutional alloys from first principles. The focus is restricted to vacancy mediated and grain boundaries that can act as vacancy sources) and diffusion in a solid containing a continuous

Ceder, Gerbrand

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


341

Compliant mechanism learning toolkit  

E-Print Network [OSTI]

This thesis concerns a toolkit designed to assist in learning the behavior of complaint mechanisms. In the design of complaint mechanisms, increasingly complicated designs behave in ways that are harder to intuitively ...

Allard, Nicholas (Nicholas A.)

2006-01-01T23:59:59.000Z

342

Programmable Mechanical Metamaterials  

E-Print Network [OSTI]

We create mechanical metamaterials whose response to uniaxial compression can be programmed by lateral confinement, allowing monotonic, non-monotonic and hysteretic behavior. These functionalities arise from a broken rotational symmetry which causes highly nonlinear coupling of deformations along the two primary axes of these metamaterials. We introduce a soft mechanism model which captures the programmable mechanics, and outline a general design strategy for confined mechanical metamaterials. Finally, we show how inhomogeneous confinement can be explored to create multi stability and giant hysteresis.

Bastiaan Florijn; Corentin Coulais; Martin van Hecke

2014-07-17T23:59:59.000Z

343

The influence of TiSi2 and CoSi2 growth on Si native point defects: The role of the diffusing species  

E-Print Network [OSTI]

from codeposited metal and Si. The as-deposited films had the compositions Ti, TiSi0.8 , TiSi2 undersaturation.3 Nevertheless, the mechanism by which silicide films effect a perturbance in the point defect, causing a va- cancy supersaturation. The formation of CoSi2 from CoSi proceeds via diffusion of metal

Florida, University of

344

Overcoming Barriers to the Transfer and Diffusion of Climate Technologies |  

Open Energy Info (EERE)

Overcoming Barriers to the Transfer and Diffusion of Climate Technologies Overcoming Barriers to the Transfer and Diffusion of Climate Technologies Jump to: navigation, search Tool Summary Name: Overcoming Barriers to the Transfer and Diffusion of Climate Technologies Agency/Company /Organization: UNEP-Risoe Centre Sector: Energy, Climate Focus Area: Greenhouse Gas Topics: Technology characterizations Resource Type: Publications, Guide/manual, Training materials Website: uneprisoe.org/ Cost: Free Overcoming Barriers to the Transfer and Diffusion of Climate Technologies Screenshot References: UNEP-Risoe[1] Logo: Overcoming Barriers to the Transfer and Diffusion of Climate Technologies This guidebook deals with the transfer of proven technologies both between countries and within them. "The purpose of the TNA project is to assist participant developing country

345

Orientation Visit to the Paducah Gaseous Diffusion Plant, July 2011 |  

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

Orientation Visit to the Paducah Gaseous Diffusion Plant, July 2011 Orientation Visit to the Paducah Gaseous Diffusion Plant, July 2011 Orientation Visit to the Paducah Gaseous Diffusion Plant, July 2011 The U.S. Department of Energy (DOE) Office of Enforcement and Oversight, within the Office of Health, Safety and Security (HSS), conducted an orientation visit to the DOE Paducah Site Office (PAD) from July 25-27, 2011. The purpose of the visit was to discuss the nuclear safety oversight strategy, describe the site lead program, increase HSS personnel's operational awareness of the site's activities, and to determine how HSS can carry out its independent oversight and mission support responsibilities. Orientation Visit to the Paducah Gaseous Diffusion Plant, July 2011 More Documents & Publications Independent Activity Report, Portsmouth Gaseous Diffusion Plant - August

346

DOE - Office of Legacy Management -- Portsmouth Gaseous Diffusion Plant -  

Office of Legacy Management (LM)

Portsmouth Gaseous Diffusion Plant Portsmouth Gaseous Diffusion Plant - 026 FUSRAP Considered Sites Site: Portsmouth Gaseous Diffusion Plant (026 ) Designated Name: Alternate Name: Location: Evaluation Year: Site Operations: Site Disposition: Radioactive Materials Handled: Primary Radioactive Materials Handled: Radiological Survey(s): Site Status: The Portsmouth Gaseous Diffusion Plant (PGDP) is located in south central Ohio, approximately 20 miles north of Portsmouth, Ohio and 70 miles south of Columbus, Ohio. Construction of the PGDP began in late 1952 to expand the Federal Government¿s gaseous diffusion program already in place at Oak Ridge, Tennessee and Paducah, Kentucky. The facility was built to increase the production of enriched uranium at rates substantially above the other

347

Diffusion maximum as a function of size in dense liquids  

Science Journals Connector (OSTI)

We study the diffusion of small guest particles of different sizes in a host fluid at liquid densities using molecular dynamics simulations. We observe an enhancement of the diffusivity of guest particles for a size related to the structure of the void space of the host fluid, analogous to the “levitation effect” observed for guest diffusion in porous solids. Friction and activation energy are found to be minimum for the guest size with maximum self-diffusivity. Wavelength dependent self-diffusivity indicates a monotonic and oscillatory dependence on wave number k for anomalous and linear regimes, respectively. These are associated with single and bi-exponential decay of the incoherent intermediate scattering function.

Pradip Kr. Ghorai; A. V. Anil Kumar; Srikanth Sastry; S. Yashonath

2005-09-16T23:59:59.000Z

348

Mechanical & Industrial Engineering  

E-Print Network [OSTI]

Mechanical & Industrial Engineering Mario A. Rotea Professor and Department Head #12;2Mechanical & Industrial Engineering Outline · Undergraduate Degree Programs · Graduate Degree Programs · The Faculty · The Research · Summary #12;3Mechanical & Industrial Engineering Undergraduate Programs ­ BSME & BSIE 0 20 40 60

Mountziaris, T. J.

349

Mechanical engineering Department Seminar  

E-Print Network [OSTI]

Mechanical engineering Department Seminar Shuodao Wang Postdoctoral Fellow University of Illinois, Urbana-Champaign Mechanical Design and Fabrication Techniques for Bio-Electronic Systems 11:00 AM Friday that bridge this gap in mechanics and form will create new opportunities in bio-inspired and bio

Lin, Xi

350

Mechanical and Aerospace Engineering  

E-Print Network [OSTI]

Mechanical and Aerospace Engineering Abstract Solid materials used in energy conversion and storage that couples the mechanical and chemical (or electrochemical) fields in solids via the use of stress-chemo- mechanical theory, two examples of practical interest will be discussed, namely, solid oxide fuel cells

351

Mechanical engineering Department Seminar  

E-Print Network [OSTI]

Mechanical engineering Department Seminar Maureen Lynch Postdoctoral Fellow Cornell University Mechanical Loading Decreases Osteolysis and Tumor Formation via Effects on Bone Remodeling 11:00 AM Friday to mechanical stimuli in the skeleton, yet the role of biomechanical loading remains poorly characterized

Lin, Xi

352

Victor Yakhot Mechanical Engineering  

E-Print Network [OSTI]

to flows of strongly non-linear fluids relevant for mechanical engineering, polymers and bio-fluid dynamicsVictor Yakhot Mechanical Engineering UniversalReynoldsNumberofTransition,Renormalizationand Mechanical Engineering 11 AM Friday, October 31st Room 245, 110 Cummington Mall Refreshments served at 10

Lin, Xi

353

Detection of slow modulation wave diffusion in incommensurate barium sodium niobate by 93Nb two-dimensional exchange NMR  

Science Journals Connector (OSTI)

93Nb two-dimensional (2D) exchange NMR was used to study ultraslow motions in incommensurate barium sodium niobate (BSN) in the temperature range 500–560 K. These 2D exchange data provide strong evidence for diffusionlike motion of the modulation wave in BSN. Such motions in BSN had been previously detected by using a complementary NMR experiment, the Hahn spin-echo decay. However, since the Hahn spin-echo decay technique cannot always distinguish unambiguously between different motional mechanisms, this 2D experiment provides definitive confirmation of modulation wave diffusion and rules out other possible motional mechanisms for the Hahn spin-echo decay in this system.

Ligia Muntean and David C. Ailion

2000-12-11T23:59:59.000Z

354

Oxygen self-diffusion ``fast-paths'' in titanite single crystals and a general method for deconvolving self-diffusion  

E-Print Network [OSTI]

Oxygen self-diffusion ``fast-paths'' in titanite single crystals and a general method most other minerals, titanite rarely if ever forms perfect crystals. In addition to the point defects could occur. During the course of an experimental study of oxygen lattice diffusion in titanite, we

Watson, E. Bruce

355

Quadratic and Cubic ReactionDiffusion Fronts*  

E-Print Network [OSTI]

's student, Herr cand. Meinecke, moved a wire loop along the test tube to mark the position in the cytoplasm of frog oocytes [9], where calcium-induced calcium release provides a mechanism akin to auto- catalysis in chemical systems. Front-like calcium waves have also been found to occur on the surface

Showalter, Kenneth

356

Modeling and measurement of Al interlayer diffusion in Pd(100): A low-energy ion scattering study  

Science Journals Connector (OSTI)

The Pd(001)-(2×2)p4g-Al surface consists of 0.5 monolayer of Al diffusing into the second layer during annealing and causing a p4g clock reconstruction. This is an interesting bimetallic alloy due to the ability to shift the Al cyclically and reproducibly from the second layer to the first and then back again. This is achieved by lifting the Al from the second layer by the absorption of O2 at room temperature and then removing the oxygen with hydrogen at 200 °C. If the surface is again heated, the Al diffuses back into the second layer and again produces the clock reconstruction. This cyclic process has been found to be repeatable continuously, and scanning tunneling microscope studies have revealed that the diffusion takes place midterrace rather than at a terrace edge. A model has been derived to calculate the activation energy for this process using Fick’s second law with a special boundary condition on the second atomic layer. Furthermore, using low-energy ion scattering, the activation energy for the diffusion of Al from the first to the second atomic layer has been measured to be 0.41±0.02 eV. This value suggests that Pd atoms are segregating through the Al to the surface via the exchange process. Measurements at higher temperatures have revealed that the activation barrier for diffusion between the second and third layers is 2.0±0.4 eV, which suggests that the diffusion of the Al into the bulk is via the vacancy mechanism.

M. J. Gladys; F. Samavat; B. V. King; D. J. O’Connor

2004-04-28T23:59:59.000Z

357

Diffusion of the Cu monomer and dimer on Ag(111): Molecular dynamics simulations and density functional theory calculations  

Science Journals Connector (OSTI)

We present results of molecular dynamics (MD) simulations and density functional theory (DFT) calculations of the diffusion of Cu adatom and dimer on Ag(111). We have used potentials generated by the embedded-atom method for the MD simulations and pseudopotentials derived from the projected-augmented-wave method for the DFT calculations. The MD simulations (at three different temperatures: 300, 500, and 700 K) show that the diffusivity has an Arrhenius behavior. The effective energy barriers obtained from the Arrhenius plots are in excellent agreement with those extracted from scanning tunneling microscopy experiments. While the diffusion barrier for Cu monomers on Ag(111) is higher than that reported (both in experiment and theory) for Cu(111), the reverse holds for dimers [which, for Cu(111), has so far only been theoretically assessed]. In comparing our MD result with those for Cu islets on Cu(111), we conclude that the higher barriers for Cu monomers on Ag(111) results from the comparatively large Ag-Ag bond length, whereas for Cu dimers on Ag(111) the diffusivity is taken over and boosted by the competition in optimization of the Cu-Cu dimer bond and the five nearest-neighbor Cu-Ag bonds. Our DFT calculations confirm the relatively large barriers for the Cu monomer on Ag(111)—69 and 75 meV—compared to those on Cu(111) and hint a rationale for them. In the case of the Cu dimer, the relatively long Ag-Ag bond length makes available a diffusion route whose highest relevant energy barrier is only 72 meV and which is not favorable on Cu(111). This process, together with another involving an energy barrier of 83 meV, establishes the possibility of low-barrier intercell diffusion by purely zigzag mechanisms.

Sardar Sikandar Hayat; Marisol Alcántara Ortigoza; Muhammad A. Choudhry; Talat S. Rahman

2010-08-03T23:59:59.000Z

358

Mechanical seal assembly  

DOE Patents [OSTI]

An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transferring it to the mechanical diode.

Kotlyar, Oleg M. (Salt Lake City, UT)

2001-01-01T23:59:59.000Z

359

Mechanical seal assembly  

DOE Patents [OSTI]

An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transfering it to the mechanical diode.

Kotlyar, Oleg M. (Salt Lake City, UT)

2002-01-01T23:59:59.000Z

360

Low-temperature lithium diffusion in simulated high-level boroaluminosilicate nuclear waste glasses  

Science Journals Connector (OSTI)

Abstract Ion exchange is recognized as an integral, if underrepresented, mechanism influencing glass corrosion. However, due to the formation of various alteration layers in the presence of water during the corrosion process, it is difficult to conclusively deconvolute the mechanisms of ion exchange from other simultaneously occurring processes. In this work, an inert non-aqueous solution was used as an alkali source material to isolate ion exchange and study the solid-state diffusion of lithium. Specifically, the experiments involved contacting simulated nuclear waste glass coupons, the 6-oxide CJ6 and the 26-oxide SON68, with a non-aqueous solution of 6LiCl dissolved in dimethyl sulfoxide at 90 °C for various time periods. The depth profiles of major elements in the glass coupons were measured using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Lithium interdiffusion coefficients, DLi, were then calculated based on the measured depth profiles. The results indicate that the penetration of 6Li is faster in the simplified CJ6 (D6Li ? 4.0–8.0 × 10? 21 m2/s) compared to the more complex SON68 (D6Li ? 2.0–4.0 × 10? 21 m2/s). These values are roughly an order of magnitude greater than measured water diffusion in glasses at similar temperatures. Additionally, sodium ions present in the glass were observed to participate in ion exchange reactions with lithium from the solution. Implications of the diffusion coefficients obtained in the absence of alteration layers to the long-term performance of nuclear waste glasses in a geological repository system are also discussed.

James J. Neeway; Sebastien Kerisit; Stéphane Gin; Zhaoying Wang; Zihua Zhu; Joseph V. Ryan

2014-01-01T23:59:59.000Z

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


361

Molecular Characterization of Organic Content of Soot along the Centerline of a Coflow Diffusion Flame  

SciTech Connect (OSTI)

High-resolution mass spectrometry coupled with nanospray desorption electrospray ionization was used to probe chemical constituents of young soot particles sampled along the centerline of a coflow diffusion flame of a three-component Jet-A1 surrogate. In lower positions where particles are transparent to light extinction (n= 632.8 nm), peri-condensed polycyclic aromatic hydrocarbons (PAHs) are found to be the major components of the particle material. These particles become enriched with aliphatic components as they grow in mass and size. Before carbonization occurs, the constituent species in young soot particles are aliphatic and aromatic compounds 200-600 amu in mass, some of which are oxygenated. Particles dominated by PAHs or mixtures of PAHs and aliphatics can both exhibit liquid-like appearance observed by electron microscopy and be transparent to visible light. The variations in chemical composition observed here indicate that the molecular processes of soot formation in coflow diffusion flames may be more complex than previously thought. For example, the mass growth and enrichment of aliphatic components in an initially, mostly aromatic structure region of the flame that is absent of H atoms or other free radicals indicates that there must exist at least another mechanism of soot mass growth in addition to the hydrogen-abstraction-carbon addition mechanism currently considered in fundamental models of soot formation.

Cain, Jeremy P.; Laskin, Alexander; Kholghy, Mohammad Reza; Thomson, Murray; Wang, Hai

2014-10-29T23:59:59.000Z

362

Diffusion modeling of fission product release during depressurized core conduction cooldown conditions  

SciTech Connect (OSTI)

A simple model for diffusion through the silicon carbide layer of TRISO particles is applied to the data for accident condition testing of fuel spheres for the High-Temperature Reactor program of the Federal Republic of Germany (FRG). Categorization of sphere release of {sup 137}Cs based on fast neutron fluence permits predictions of release with an accuracy comparable to that of the US/FRG accident condition fuel performance model. Calculations are also performed for {sup 85}Kr, {sup 90}Sr, and {sup 110m}Ag. Diffusion of cesium through SiC suggests that models of fuel failure should consider fuel performance during repeated accident condition thermal cycling. Microstructural considerations in models in fission product release are discussed. The neutron-induced segregation of silicon within the SiC structure is postulated as a mechanism for enhanced fission product release during accident conditions. An oxygen-enhanced SiC decomposition mechanism is also discussed. 12 refs., 11 figs., 2 tabs.

Martin, R.C.

1990-01-01T23:59:59.000Z

363

Understanding the Regional Variability of Eddy Diffusivity in the Pacific Sector of the Southern Ocean  

E-Print Network [OSTI]

A diagnostic framework is presented, based on the Nakamura effective diffusivity, to investigate the regional variation in eddy diffusivity. Comparison of three different diffusivity calculations enables the effects of ...

Shuckburgh, Emily

364

The Hidden Geometry of Attention Diffusion  

E-Print Network [OSTI]

It is difficult to develop quantitative hypotheses to describe the diffusion of information among users, because, in theory, information resources can have an infinite number of copies. And this theoretical possibility has become a reality in an age of information explosion, when a Twitter meme may spread rapidly to millions of users in a few hours. To address this issue, we propose to study the transportation of users' attention between information resources. We use clicks as a proxy of attention and construct attention networks using the browsing log files from 1,000 Web forums. Our previous research discovered the scaling relationship between clicks and users with an exponent $\\theta$ that characterizes the efficiency of forums in spreading information. In this paper we propose a geometric model to explain this scaling property. We view attention networks as $d$-dimensional flow-balls that satisfy $\\theta=(d+1)/d$ and we find that the time-invariant parameter $d$ can be estimated from the spatial distribut...

Wu, Lingfei; Janssen, Marco; Zhang, Jiang; Zhao, Min

2015-01-01T23:59:59.000Z

365

Characterising cosmic inhomogeneity with anomalous diffusion  

E-Print Network [OSTI]

Dark matter (DM) clustering at the present epoch is investigated from a fractal viewpoint to determine the scale where the self-similar scaling property of the DM halo distribution transits to homogeneity. Methods based on well-established counts-in-spheres, as well as new methods based on anomalous diffusion and random walks, are applied both to DM halos of the biggest N-Body simulation in the `Dark Sky Simulations' (DS) and an equivalent randomly distributed catalogue. Results for the smaller `Millennium Run' (MR) simulation are revisited. It is found that the MR simulation volume is too small and prone to bias to reliably identify the onset of homogeneity. Transition to homogeneity is defined when the fractal dimension of the clustered and random distributions cannot be distinguished within the associated uncertainties. The `counts-in-spheres' method applied to the DS simulation then yields a homogeneity scale roughly consistent with previous work ($\\sim 150$ Mpc/h). The characteristic length-scale for ano...

Kraljic, David

2014-01-01T23:59:59.000Z

366

Manhattan Project: The Navy and Thermal Diffusion, 1944  

Office of Scientific and Technical Information (OSTI)

Diffusion columns, S-50 Thermal Diffusion Plant, Oak Ridge, 1945. THE NAVY AND THERMAL DIFFUSION Diffusion columns, S-50 Thermal Diffusion Plant, Oak Ridge, 1945. THE NAVY AND THERMAL DIFFUSION (Oak Ridge: Clinton, 1944) Events > The Uranium Path to the Bomb, 1942-1944 Y-12: Design, 1942-1943 Y-12: Construction, 1943 Y-12: Operation, 1943-1944 Working K-25 into the Mix, 1943-1944 The Navy and Thermal Diffusion, 1944 As problems with both Y-12 and K-25 reached crisis proportions in spring and summer 1944, the Manhattan Project received help from an unexpected source: the United States Navy. President Roosevelt had instructed that the atomic bomb effort be an Army program and that the Navy be excluded from deliberations. Navy research on atomic power, conducted primarily for submarines, received no direct aid from Leslie Groves, who, in fact, was not up-to-date on the state of Navy efforts when he received a letter on the subject from Robert Oppenheimer late in April 1944.

367

Oxygen and nitrogen diffusion in ?-hafnium from first principles  

SciTech Connect (OSTI)

We use a combination of density functional theory and multistate diffusion formalism to analyze the diffusion of oxygen and nitrogen in technologically important hafnium metal. Comparing the local density approximation and the Perdew-Burke-Ernzerhof version of the generalized gradient approximation, we find that a better description of the hafnium lattice in the latter results in the correct sequence of stable and transition states for oxygen interstitials leading to essentially quantitative agreement with experiment. For oxygen diffusion, we find an isotropic temperature-dependent diffusion coefficient of D=0.082e{sup ?2.04/k{sub B}T}cm{sup 2}s{sup ?1} utilizing interstitial sites with hexahedral and octahedral coordination. For the diffusivity of nitrogen, we find that an additional stable interstitial site, the crowdion site, exists and that the diffusion coefficient is D=0.15e{sup ?2.68/k{sub B}T}cm{sup 2}s{sup ?1}. Our results also reproduce the experimental observation that nitrogen diffusivity is lower than that of oxygen in hafnium.

O'Hara, Andrew; Demkov, Alexander A., E-mail: demkov@physics.utexas.edu [Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)

2014-05-26T23:59:59.000Z

368

Chapter 30 - Air Pollution Control Technologies  

Science Journals Connector (OSTI)

Abstract This chapter describes numerous air pollution control devices and approaches to remove and treat particulate-phase and vapor-phase contaminants from a gas stream. Beginning with the removal of particulate matter, the various forces are described; i.e. gravity, buoyancy, drag, centrifugal and electrostatic forces, as well as molecular diffusion, and phoresis (thermal and diffusion-based). For removing gas-phase compounds, absorption and adsorption processes are described in detail. The physical and chemical mechanisms at work in gravitational settling, inertial impaction, electrostatic precipitation, filtration, and sorption are discussed in detail. Example calculations are provided, as well as expected problems and considerations needed prior to selecting a technology for a given pollutant stream.

Daniel Vallero

2014-01-01T23:59:59.000Z

369

Diffusion and effusion of hydrogen in microcrystalline silicon  

SciTech Connect (OSTI)

The diffusion and effusion of hydrogen in hydrogenated microcrystalline silicon films deposited in an electron cyclotron resonance reactor were studied for various deposition temperatures T{sub s}. For deposition temperatures below 250 C, hydrogen effusion is found to be dominated by desorption of hydrogen from internal surfaces followed by rapid out-diffusion of H{sub 2}. Higher substrate temperatures result in an increased hydrogen stability suggesting the growth of a more compact material. For this latter type of samples, a hydrogen diffusion coefficient similar as in compact plasma-grown a-Si:H films is found despite a different predominant bonding of hydrogen according to infrared absorption.

Beyer, W.; Hapke, P.; Zastrow, U.

1997-07-01T23:59:59.000Z

370

Effect of elasticity of wall on diffusion in nano channel  

SciTech Connect (OSTI)

Confining walls of nano channel are taken to be elastic to study their effect on the diffusion coefficient of fluid flowing through the channel. The wall is elastic to the extent that it responses to molecular pressure exerted by fluid. The model to study diffusion is based on microscopic considerations. Results obtained for fluid confining to 20 atomic diameter width contrasted with results obtained by considering rigid and smooth wall. The effect of roughness of wall on diffusion can be compensated by the elastic property of wall.

Tankeshwar, K., E-mail: tankesh@pu.ac.in [Computer Centre, Panjab University Chandigarh,- 160014 (India); Srivastava, Sunita [Department of Physics, Panjab University, Chandigarh 160014 (India)

2014-04-24T23:59:59.000Z

371

Energy diffusion in strongly driven quantum chaotic systems  

E-Print Network [OSTI]

The energy evolution of a quantum chaotic system under the perturbation that harmonically depends on time is studied for the case of large perturbation, in which the rate of transition calculated from the Fermi golden rule exceeds the frequency of perturbation. It is shown that the energy evolution retains its diffusive character, with the diffusion coefficient that is asymptotically proportional to the magnitude of perturbation and to the square root of the density of states. The results are supported by numerical calculation. They imply the absence of the quantum-classical correspondence for the energy diffusion and the energy absorption in the classical limit $\\hbar \\to 0$.

P. V. Elyutin

2005-04-14T23:59:59.000Z

372

Roughened quartz surfaces and Teflon as small angle diffusers and depolarizers between 200 and 400 nm  

Science Journals Connector (OSTI)

Laboratory tests of transmission diffusers are reported for quartz and Teflon. These tests were conducted to select transmission diffusers for the NOAA rocket flight UV...

Saunders, Robert D; Kostkowski, Henry J

1989-01-01T23:59:59.000Z

373

E-Print Network 3.0 - ambipolar diffusion calcuations Sample...  

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

by the diffusion would move the ions together... and thus reducing the total diffusion rate close to ... Source: Ng, Chung-Sang - Department of Geology and Geophysics,...

374

E-Print Network 3.0 - agar diffusion cytotoxicity Sample Search...  

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

diffusion cytotoxicity Search Powered by Explorit Topic List Advanced Search Sample search results for: agar diffusion cytotoxicity Page: << < 1 2 3 4 5 > >> 1 J. Embryol. exp....

375

E-Print Network 3.0 - acetylene jet diffusion Sample Search Results  

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

the case of acetylene, we can... before they escape by diffusion. Conse- quently, the heat generated in acetylene has the same spatial... times in acetylene be- fore diffusion...

376

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

E-Print Network [OSTI]

The short diffusion lengths in insertion battery nanoparticles render the capacitive behavior of bounded diffusion, which is rarely observable with conventional larger particles, now accessible to impedance measurements. ...

Song, Juhyun

377

E-Print Network 3.0 - anomalous diffusion dynamics Sample Search...  

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

and diffusive phonons coexist, and the thermal conductivity exhibits anomalous nonlinear tube-length dependence... 1 - Crossover from ballistic to diffusive thermal transport in...

378

Coherence theory of a laser beam passing through a moving diffuser  

Science Journals Connector (OSTI)

Abstract: We present the general coherence theory for laser beams passing through a moving diffuser. The temporal coherence of laser beams passing through a moving diffuser depends on...

Li, Gaoming; Qiu, Yishen; Li, Hui

2013-01-01T23:59:59.000Z

379

E-Print Network 3.0 - advanced diffusion model Sample Search...  

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

of Michigan Collection: Geosciences 2 Oxygen self-diffusion fast-paths'' in titanite single crystals and a general method for deconvolving self-diffusion Summary:...

380

E-Print Network 3.0 - advanced stage diffuse Sample Search Results  

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

of Rochester Collection: Physics 95 Oxygen self-diffusion fast-paths'' in titanite single crystals and a general method for deconvolving self-diffusion Summary: Oxygen...

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While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

E-Print Network 3.0 - advanced diffusion studies Sample Search...  

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

State University Collection: Chemistry 3 Oxygen self-diffusion fast-paths'' in titanite single crystals and a general method for deconvolving self-diffusion Summary: could...

382

E-Print Network 3.0 - anomalous diffusion due Sample Search Results  

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

and Technology Collection: Mathematics 97 Oxygen self-diffusion fast-paths'' in titanite single crystals and a general method for deconvolving self-diffusion Summary: profile...

383

Iron self-diffusion in amorphous FeZr?Fe57Zr multilayers measured by neutron reflectometry  

Science Journals Connector (OSTI)

Self-diffusion of iron in Fe67naturalZr33?Fe6757Zr33 multilayers has been investigated by neutron reflectometry. The as-deposited multilayer is amorphous in nature. It remains amorphous up to a temperature of 573K and thereafter nanocrystallizes with an average grain size of 6nm. The self-diffusion in the multilayers has been measured after isothermal vacuum annealing below the nanocrystallization temperature by monitoring the decay of the intensity of the first order Bragg peak, arising due to the isotopic periodicity. It has been found that the diffusivity at different temperatures follows an Arrhenius-type behavior with the preexponential factor D0=5×10?18±1m2s?1 and the activation energy E=0.38±0.05eV, respectively. These values of E and D0 follow the well-known E–D0 correlation and on the basis of this correlation it is suggested that diffusion mechanism in the present case is not highly collective but involves a rather small group of atoms.

Mukul Gupta; Ajay Gupta; J. Stahn; M. Horisberger; T. Gutberlet; P. Allenspach

2004-11-18T23:59:59.000Z

384

Mechanical Properties of Nanocrystal Supercrystals  

E-Print Network [OSTI]

and Its Impact on Mechanical Properties. MacromoleculesO. L. ; Minor, A. M. , Mechanical annealing and source-Mechanical Properties of Nanocrystal Supercrystals Enrico

Tam, Enrico

2010-01-01T23:59:59.000Z

385

Mechanics of Funding matrix  

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

FUNDING MECHANISMS FUNDING MECHANISMS Funding Mechanism Advantages Disadvantages Comments 1. From Doe to regional organizations * * Facilitates a broad, regional approach to planning and implementation that enhances consistency and uniformity * * Especially beneficial for new programs where early planning is needed * * Simplifies communication for DOE to have only one point of contact for information and discussion * * Cooperative agreement mechanism has proven relatively simple to administer * * Approach would require modification for Tribes * * Would also require that funding be provided to individual States to enable them to participate in the process, since planning authority and responsibility rests with the individual State * * Differs from OCRWM approach to 180(c) funding * * Introduces another layer of

386

Technology Partnering Mechanisms  

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

expand a business with INL technologies, or require business support our Technology Transfer team is available to discuss the following contractual mechanisms: Cooperative...

387

An Instrument Design Concept for Measuring Solar Diffuse Irradiance  

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

An Instrument Design Concept for Measuring Solar Diffuse Irradiance An Instrument Design Concept for Measuring Solar Diffuse Irradiance Rutledge, Charles NASA Langley Research Center Schuster, Greg NASA Langley Research Center Category: Instruments Recent effort towards the development of a diffuse horizontal solar irradiance standard group [Michalsky et.al. 2005] using well calibrated pyranometers suggested that inter-instrument differences in cosine response characteristics may be problematic. They showed a calibration method using overcast skies (an approximately uniform radiance distribution) produced superior diffuse radiometer performance when compared to a calibration method using clear skies (which have a radiance distribution systematically varying from horizon to the near vicinity of the sun). The proposed instrument offers a significantly different basic design compared to

388

Diffuse Neutron Scattering from Crystal Imperfections [and Discussion  

Science Journals Connector (OSTI)

...1980 research-article Diffuse Neutron Scattering from Crystal Imperfections...years has been the small angle scattering centred on 000. Examples are...comparison with small angle neutron scattering, much less work has been done...

1980-01-01T23:59:59.000Z

389

Determinants of the diffusion of U.S. digital telecommunications  

Science Journals Connector (OSTI)

This paper examines the diffusion of digital switches from 1983 to 1996. It expands upon the existing literature by extending the data available back an additional six years and by adding independent companies...

Allan Shampine

2001-02-01T23:59:59.000Z

390

Lattice Boltzmann Scheme for Diffusion on Triangular Grids  

Science Journals Connector (OSTI)

In this paper we present a Lattice Boltzmann scheme for diffusion on it unstructured triangular ... At the end of the propagation step the lattice gas particles arrive exactly at neighbouring lattice sites, as is...

R. G. M. van der Sman

2003-01-01T23:59:59.000Z

391

Bitumen–Toluene Mutual Diffusion Coefficients Using Microfluidics  

Science Journals Connector (OSTI)

Bitumen–Toluene Mutual Diffusion Coefficients Using Microfluidics ... Determination of Dew Point Conditions for CO2 with Impurities Using Microfluidics ... Determination of Dew Point Conditions for CO2 with Impurities Using Microfluidics ...

Hossein Fadaei; John M. Shaw; David Sinton

2013-03-08T23:59:59.000Z

392

Diffusion suppression in gel dosimetry by addition of nanoclay  

Science Journals Connector (OSTI)

This paper reports diffusion suppression in gel dosimetery by using nanocomposite gel. A Fricke xylenol gel (FXG) and a dichromate gel (DCG) were selected for adding a small amount of nanoclay (Laponite XLG). The...

T. Maeyama; N. Fukunishi; K. L. Ishikawa…

2013-01-01T23:59:59.000Z

393

Transportation cost inequalities for diffusions under uniform distance  

E-Print Network [OSTI]

We prove the transportation inequality with the uniform norm for the laws of diffusion processes with Lipschitz and/or dissipative coefficients and apply them to some singular stochastic differential equations of interest.

Ali Suleyman Ustunel

2010-09-27T23:59:59.000Z

394

Perpendicular Diffusion of Energetic Particles in Collisionless Plasmas  

E-Print Network [OSTI]

A fundamental problem in plasma and astrophysics is the interaction between energetic particles and magnetized plasmas. In the current paper we focus on particle diffusion across the guide magnetic field. It is shown that the perpendicular diffusion coefficient depends only on the parallel diffusion coefficient and the Kubo number. Therefore, one can find four asymptotic limits depending on the values of these two parameters. These regimes are the quasilinear limit, the Kadomtsev & Pogutse limit, the scaling of Rechester & Rosenbluth, and the scaling found by Zybin & Istomin. In the current article we focus on the Rechester & Rosenbluth scenario because this was not discovered before in the context of collisionless plasmas. Examples and applications are discussed as well. We show that an energy independent ratio of perpendicular and parallel diffusion coefficients can be found and that this ratio can be very small but also close to unity. This is exactly what one observes in the solar wind.

Shalchi, Andreas

2015-01-01T23:59:59.000Z

395

Uranium(VI) Diffusion in Low-Permeability Subsurface Materials...  

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

Abstract: Uranium(VI) diffusion was investigated in a fine-grained saprolite sediment that was collected from U.S. Department of Energy (DOE) Oak Ridge site, TN, where...

396

Diffusion of propane (1); 2-methyl-propane (2)  

Science Journals Connector (OSTI)

This document is part of Subvolume A ‘Gases in Gases, Liquids and their Mixtures’ of Volume 15 ‘Diffusion in Gases, Liquids and Electrolytes’ of Landolt-Börnstein Group IV ‘Physical Chemistry’. It is part of the ...

J. Winkelmann

2007-01-01T23:59:59.000Z

397

Big Data Projects on Solar Tech Evolution and Diffusion  

Broader source: Energy.gov [DOE]

This is the meeting agenda from the Big Data Projects on Solar Technology Evolution and Diffusion kickoff meeting, held on July 15, 2013 in Arlington, VA and facilitated by the SunShot Initiative.

398

Ultrasonic NDT of titanium diffusion bonding with guided waves  

SciTech Connect (OSTI)

An ultrasonic guided wave technique is developed for the NDT of diffusion bonded titanium-to-titanium structures. A three-layer model based on the normal beam experimental results has been proposed. Dispersion curves and wave structure are analyzed to direct the experimental study. Two features related to Lamb waves propagating in diffusion bonded titanium plates, the spectral peak to peak ratios and the wave mode frequency shift, are extracted from the guided wave experimental results for both 2 mm (0.08 in.) and 4 mm (0.16 in.) diffusion bond panels. It is found for some specific modes and frequencies that these two features are sensitive to the diffusion bonding states and, therefore, could be used to distinguish good bond panels from poor bond ones.

Rose, J.L.; Zhu, W. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Engineering Science and Mechanics; Zaidi, M. [Boeing Co., Long Beach, CA (United States)

1998-04-01T23:59:59.000Z

399

Demolition of K-31 gaseous diffusion building begins  

Broader source: Energy.gov [DOE]

OREM begins demolition of the K-31 Building at Oak Ridge’s East Tennessee Technology Park (ETTP), marking the removal of the fourth of five gaseous diffusion buildings at the former uranium enrichment site.

400

CORELLI: the Elastic Diffuse Scattering Spectrometer at SNS | ORNL Neutron  

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

The Elastic Diffuse Scattering Spectrometer The Elastic Diffuse Scattering Spectrometer CORELLI The CORELLI instrument. CORELLI is a statistical chopper spectrometer with energy discrimination. It's designed and optimized to probe complex disorder in crystalline materials through diffuse scattering of single-crystal samples. The momentum transfer ranges from 0.5 to 12 Å-1, and the energy of incident neutrons ranges from 10 to 200 meV. This instrument combines the high efficiency of white-beam Laue diffraction with energy discrimination by modulating the beam with a statistical chopper. A cross-correlation method is used to reconstruct the elastic signal from the modulated data. Accurate modeling of the short-range order associated with the diffuse scattering requires measurements over large volumes of three-dimensional reciprocal space, with sufficient momentum

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


401

Energy Department Completes K-25 Gaseous Diffusion Building Demolition |  

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

Energy Department Completes K-25 Gaseous Diffusion Building Energy Department Completes K-25 Gaseous Diffusion Building Demolition Energy Department Completes K-25 Gaseous Diffusion Building Demolition December 19, 2013 - 12:00pm Addthis K-25 Demolition - Oak Ridge 2013 K-25 Demolition - Oak Ridge 2013 Media Contacts Ben Williams, DOE, (865) 574-4912 Wayne McKinney, UCOR, (865) 576-6284 Oak Ridge, Tenn. - Today, the Department of Energy announced that its contractor URS|CH2M Oak Ridge, LLC, or UCOR, has completed demolition of the K-25 gaseous diffusion building, the largest facility in the DOE complex. UCOR took over the project in 2011 and has maintained a strong safety record while completing the demolition over one year ahead of its current schedule and approximately $300 million under the current budget. All debris removal is expected to be completed in spring 2014.

402

Stabilised nonlinear inverse diffusion for approximating hyperbolic PDEs  

Science Journals Connector (OSTI)

Stabilised backward diffusion processes have shown their use for a number of image enhancement tasks. The goal of this paper is to show that they are also highly useful for designing shock capturing numerical schemes for hyperbolic conservation laws. ...

Michael Breuß; Thomas Brox; Thomas Sonar; Joachim Weickert

2005-04-01T23:59:59.000Z

403

Investigation of porous media structures using NMR restricted diffusion measurements  

E-Print Network [OSTI]

INVESTIGATION OF POROUS MEDIA STRUCTURES USING NMR RESTRICTED DIFFUSION MEASUREMENTS A Thesis by PEIZHI MIAO Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1993 Major Subject: Chemical Engineering INVESTIGATION OF POROUS MEDIA STRUCTURES USING NMR RESTRICTED DIFFUSION MEASUREMENTS A Thesis by PEIZHI MIAO Approved ss to style and content by: A. T. Watson (Chair of Committee) C...

Miao, Peizhi

2012-06-07T23:59:59.000Z

404

Discretisation and solution of quasi-diffusion equations  

E-Print Network [OSTI]

DISCRETISATION AND SOLUTION OF QUASI-DIFFUSION EQUATIONS A Thesis by NICOLAS DOMINIQUE VALETTE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... August 2002 Major Subject: Nuclear Engineering DISCRETISATION AND SOLUTION OF QUASI-DIFFUSION EQUATIONS A Thesis by NICOLAS DOMINIQUE VALETTE Submitted to Texas A&M University in partial fu]fillment of the requirements for the degree of MASTER...

Valette, Nicolas Dominique

2012-06-07T23:59:59.000Z

405

Classical phase diffusion in small hysteretic Josephson junctions  

SciTech Connect (OSTI)

The existence of classical phase diffusion in hysteretic junctions is demonstrated by quantitative agreement between experimental and simulated {ital I}-{ital V} curves. The simulations are based on a circuit that accurately models both the junction and its external shunting impedance at microwave frequencies. We show that the bias current at which the junction switches from the phase diffusion state to the voltage state is sensitive to dissipation at microwave frequencies.

Martinis, J.M.; Kautz, R.L. (National Institute of Standards and Technology, Boulder, Colorado 80303 (US))

1989-10-02T23:59:59.000Z

406

Spectral-Spatial Diffusion of Resonantly Trapped Phonons  

Science Journals Connector (OSTI)

The observation of spectral and spatial diffusion of phonons in an Al2O3 crystal containing both inelastic and resonance-elastic scattering centers (two different species of impurity ions) is reported. Phonons were generated by pulsed far-infrared excitation at a fixed frequency and monitored by time-resolved detection at a different frequency. Analysis of the data leads to the determination of the basic parameters of spectral and spatial diffusion.

U. Happek; T. Holstein; K. F. Renk

1985-05-13T23:59:59.000Z

407

Anisotropic Diffusion of Polyelectrolyte Chains within Multi-layer Films  

SciTech Connect (OSTI)

We found diffusion of polyelectrolyte chains within multilayer films to be highly anisotropic, with the preferential chain motion parallel to the substrate. The degree of anisotropy was quantified by a combination of fluorescence recovery after photobleaching and neutron reflectometry, probing chain diffusion in directions parallel and perpendicular to the substrate, respectively. Chain mobility was controlled by ionic strength of annealing solutions and steric hindrance to ionic pairing of interacting polyelectrolytes.

Xu, Li [Stevens Institute of Technology, Hoboken, New Jersey; Kozlovskaya, Veronika [University of Alabama, Birmingham; Kharlampieva, Eugenia [University of Alabama, Birmingham; Ankner, John Francis [ORNL; Sukhishvili, Prof. Svetlana A. [Stevens Institute of Technology, Hoboken, New Jersey

2012-01-01T23:59:59.000Z

408

Boston University Department of Mechanical Engineering ME 303 Fluid Mechanics  

E-Print Network [OSTI]

Boston University Department of Mechanical Engineering ME 303 ­ Fluid Mechanics Fall 2011 Class: EK301 Engineering Mechanics Course Textbook: Fundamentals of Fluid Mechanics, 6th ed., Munson B. Reference Texts: Fluid Mechanics, Landau and Lifshitz, Vol. 6 Fluid Mechanics, Y. Cengel and J. Cimbala

409

Growth strains and creep in thermally grown alumina : oxide growth mechanisms.  

SciTech Connect (OSTI)

In situ measurements of growth strains and creep relaxation in {alpha}-Al{sub 2}O{sub 3} films, isothermally grown on {beta}-NiAl alloys at 1100 C, are reported and analyzed. Samples containing the reactive element Zr, and Zr-free samples, are examined. For Zr-free samples, steady state growth strains are compressive, whereas the growth strains are tensile when the reactive element (RE) is added to the alloy. This behavior is attributed to the counterflow of oxygen and aluminum interstitials, and to simultaneous counterflow of oxygen and aluminum vacancies, all moving through the grain boundaries. Cross diffusing oxygen and aluminum interstitials may merge and combine within the film, forming new oxide along grain boundary walls, a mechanism that leads to an in-plane compressive stress. Cross diffusing oxygen and aluminum vacancies will also merge and combine within the film; in this case material is removed from grain boundary walls, a mechanism that leads to an in-plane tensile stress. When no RE is present, the interstitial mechanism dominates and the resultant stress is compressive. Consistent with the 'dynamic segregation model', the RE slows the outdiffusion of Al interstitials permitting the tensile mechanism to dominate. This interpretation invokes the unconventional view that oxygen and aluminum interstitials and vacancies, created in and driven by the strong chemical gradient, all participate meaningfully in the scale growth process. Grain boundary diffusion measurements were obtained from low stress creep data, interpreted using the Coble model of grain boundary diffusion. Reported diffusion measurements of oxygen through grain boundaries of {alpha}-Al{sub 2}O{sub 3}, which are known to be inconsistent with oxide scale growth, are critically examined. A simple picture, a 'balanced defect model', emerges that is consistent with the dynamic segregation model, observed growth stresses and their dependence on the presence of a reactive element, sequential oxidation experiments, and our best knowledge about grain boundary diffusion coefficients.

Veal, B. W.; Paulikas, A. P.; Materials Science Division

2008-01-01T23:59:59.000Z

410

Diffusion coefficients in trimethyleneoxide containing comb branch polymer  

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

Diffusion coefficients in trimethyleneoxide containing comb branch polymer Diffusion coefficients in trimethyleneoxide containing comb branch polymer electrolytes Title Diffusion coefficients in trimethyleneoxide containing comb branch polymer electrolytes Publication Type Journal Article Year of Publication 2004 Authors Liu, Gao, Craig L. Reeder, Xiaoguang Sun, and John B. Kerr Journal Solid State Ionics Volume 175 Pagination 781-783 Keywords comb branch polyethers, conductivity, lithium battery, polymer electrolytes, salt diffusion coefficient, trimethylene oxide Abstract This paper reports on a new comb branch polymer based on trimethylene oxide (TMO) side chains as a polymer electrolyte for potential application in lithium metal rechargeable batteries. The trimethylene oxide (TMO) units are attached to the side chains of a polyepoxide ether to maximize the segmental motion. Lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) salt was used to formulate the polymer electrolyte with the new TMO containing polymers. The new polymer electrolytes show improved salt diffusion coefficients (Ds) and conductivity at ambient and subambient temperature compare to the ethylene oxide (EO) counterpart, whereas performance at high temperature (85 °C) remains the same or is actually worse for salt diffusivity.

411

Mechanical & Aerospace Engineering  

E-Print Network [OSTI]

, and nuclear energy. She is a member of the American Society of Mechanical Engineers (ASME), Fluids EngineeringMechanical & Aerospace Engineering Interfacial flows are multi-material flows comprised of two of the interface between the fluids and the interface physics (like surface tension) needs to be predicted as part

412

MECHANICAL ENGINEERING Program of Study  

E-Print Network [OSTI]

MECHANICAL ENGINEERING Program of Study Correspondence The Department of Mechanical Engineering offers graduate programs in the fields of thermal science and engineering mechanics. Current areas of research activity include Biomedical Engineering, Biomimetics, Composite Materials, Computational Mechanics

Thomas, Andrew

413

Integrated Mechanical & Electrical Engineering (IMEE)  

E-Print Network [OSTI]

Integrated Mechanical & Electrical Engineering (IMEE) Department of Electronic & Electrical Engineering and Department of Mechanical Engineering #12;Graduates able to work in both mechanical of Mechanical Engineers (IMechE) n Develop essential engineering skills through extensive project work n Enhance

Burton, Geoffrey R.

414

Journal of the Mechanics and Physics of Solids 54 (2006) 887903  

E-Print Network [OSTI]

from prior work that OSG is sensitive to subcritical crack growth as water molecules in the environment make the material susceptible to subcritical crack growth when water is present in the environmentJournal of the Mechanics and Physics of Solids 54 (2006) 887­903 The effect of water diffusion

415

Mechanical code comparator  

DOE Patents [OSTI]

A new class of mechanical code comparators is described which have broad potential for application in safety, surety, and security applications. These devices can be implemented as micro-scale electromechanical systems that isolate a secure or otherwise controlled device until an access code is entered. This access code is converted into a series of mechanical inputs to the mechanical code comparator, which compares the access code to a pre-input combination, entered previously into the mechanical code comparator by an operator at the system security control point. These devices provide extremely high levels of robust security. Being totally mechanical in operation, an access control system properly based on such devices cannot be circumvented by software attack alone.

Peter, Frank J. (Albuquerque, NM); Dalton, Larry J. (Bernalillo, NM); Plummer, David W. (Albuquerque, NM)

2002-01-01T23:59:59.000Z

416

MEASUREMENT OF OXYGEN CONSUMPTION AND DIFFUSION IN EXPOSED AND COVERED REACTIVE MINE TAILINGS1  

E-Print Network [OSTI]

MEASUREMENT OF OXYGEN CONSUMPTION AND DIFFUSION IN EXPOSED AND COVERED REACTIVE MINE TAILINGS1 the in situ oxygen diffusion and consumption in tailings. It provides measured values for the oxygen reaction rate Kr and the effective diffusion De coefficients based on oxygen consumption and diffusion tests

Aubertin, Michel

417

Diffusion and magnetic relaxation in model porous media Aniket Bhattacharya and S. D. Mahanti  

E-Print Network [OSTI]

-dimensional analogs resemble commercially prepared Vycors and aerogels. When diffusion rates are compared for two

Bhattacharya, Aniket

418

Portsmouth Gaseous Diffusion Plant- Quadrant I Groundwater Investigative (5-Unit) Area Plume  

Broader source: Energy.gov [DOE]

Groundwater Database Report - Portsmouth Gaseous Diffusion Plant - Quadrant I Groundwater Investigative (5-Unit) Area Plume

419

Rotary mechanical latch  

DOE Patents [OSTI]

A rotary mechanical latch for positive latching and unlatching of a rotary device with a latchable rotating assembly having a latching gear that can be driven to latched and unlatched states by a drive mechanism such as an electric motor. A cam arm affixed to the latching gear interfaces with leading and trailing latch cams affixed to a flange within the drive mechanism. The interaction of the cam arm with leading and trailing latch cams prevents rotation of the rotating assembly by external forces such as those due to vibration or tampering.

Spletzer, Barry L.; Martinez, Michael A.; Marron, Lisa C.

2012-11-13T23:59:59.000Z

420

High Co2 Emissions Through Porous Media- Transport Mechanisms And  

Open Energy Info (EERE)

Co2 Emissions Through Porous Media- Transport Mechanisms And Co2 Emissions Through Porous Media- Transport Mechanisms And Implications For Flux Measurement And Fractionation Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: High Co2 Emissions Through Porous Media- Transport Mechanisms And Implications For Flux Measurement And Fractionation Details Activities (1) Areas (1) Regions (0) Abstract: Diffuse emissions of CO2 are known to be large around some volcanoes and hydrothermal areas. Accumulation-chamber measurements of CO2 flux are increasingly used to estimate the total magmatic or metamorphic CO2 released from such areas. To assess the performance of accumulation chamber systems at fluxes one to three orders of magnitude higher than normally encountered in soil respiration studies, a test system was

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


421

Counter Current Multiplier Mechanism  

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

Counter Current Multiplier Mechanism Counter Current Multiplier Mechanism Name: Stephen Location: N/A Country: N/A Date: N/A Question: Can you please explain to me the counter-current multiplier mechanism. I understand that cholride and sodium ions are filtered out of the ascending loop of Henle into the interstial fluid, however, I'm not sure exactly what happens from there and how this effects osmotic pressure gradients in the nephron. Any help would be greatly appriciated. Replies: This mechanism is very complex when it comes to writing a response. You have to have a strong background in osmotic pressure understanding and the anatomy of the kidney. It involves the cortex, outer and inner medula in relationship to the vasa recta, interstitial fluids at two points, the loop of Henle and the collecting duct. The size of the tubes and the position in relations to the cortex and medulla is an essential part. I can suggest some references.

422

Contaminant-Generation Mechanisms  

Science Journals Connector (OSTI)

In the last chapter, the areas where contaminants are generated were discussed. Knowing the location of contaminant generation is helpful in controlling that contamination, but understanding the mechanisms is ...

Alvin Lieberman

1992-01-01T23:59:59.000Z

423

Mechanical & Aerospace Engineering  

E-Print Network [OSTI]

Mechanical & Aerospace Engineering This presentation will address the development and transition of advanced structural health management (SHM) technologies from the perspective of understanding and the importance of understanding this role to increase the likelihood for transition of new technologies

424

Mechanical engineering Department Seminar  

E-Print Network [OSTI]

people trained from both perspectives can result in innovative solutions. At Fraunhofer CMI ­ coMechanical engineering Department Seminar Alexis Sauer-Budge Senior Research Scientist, Fraunhofer CMI Adjunct Research Assistant Professor, BME, Boston University Innovations at the intersection

425

Syngas Oxidation Mechanism  

Science Journals Connector (OSTI)

A comprehensive analysis of synthesis gas (syngas) oxidation kinetics in wide ranges of temperature ... on the basis of the reaction mechanism of syngas ignition and combustion in air. A vast set of experimental ...

A. M. Starik; N. S. Titova; A. S. Sharipov…

2010-09-01T23:59:59.000Z

426

Mechanical Compression Heat Pumps  

E-Print Network [OSTI]

MECHANICAL COMPRESSION HEAT PUMPS Thomas-L. Apaloo and K. Kawamura Mycom Corporation, Los Angeles, California J. Matsuda, Mayekawa Mfg. Co., Tokyo, Japan ABSTRACT Mechanical compression heat pumping is not new in industrial applications.... In fact, industry history suggests that the theoretical concept was developed before 1825. Heat pump manufacturers gained the support of consultants and end-users when the energy crisis hit this country in 1973. That interest, today, has been...

Apaloo, T. L.; Kawamura, K.; Matsuda, J.

427

Mechanical Engineering Is Mechanical Engineering right for me?  

E-Print Network [OSTI]

Mechanical Engineering Is Mechanical Engineering right for me? If you are interested in the wide range of principles related to mechanical systems then Mechanical Engineering is well suited to you. A Mechanical Engineering degree programme will focus on aspects such as analysis, design, manufacture

Harman, Neal.A.

428

Diffusion current in a system of coupled Josephson junctions  

SciTech Connect (OSTI)

The role of a diffusion current in the phase dynamics of a system of coupled Josephson junctions (JJs) has been analyzed. It is shown that, by studying the temporal dependences of the superconducting, quasi-particle, diffusion, and displacement currents and the dependences of average values of these currents on the total current, it is possible to explain the main features of the current-voltage characteristic (CVC) of the system. The effect of a diffusion current on the character of CVC branching in the vicinity of a critical current and in the region of hysteresis, as well as on the part of CVC branch corresponding to a parametric resonance in the system is demonstrated. A clear interpretation of the differences in the character of CVC branching in a model of capacitively coupled JJs (CCJJ model) and a model of capacitive coupling with diffusion current (CCJJ+DC model) is proposed. It is shown that a decrease in the diffusion current in a JJ leads to the switching of this junction to an oscillating state. The results of model calculations are qualitatively consistent with the experimental data.

Shukrinov, Yu. M., E-mail: shukrinv@theor.jinr.ru; Rahmonov, I. R. [Joint Institute for Nuclear Research (Russian Federation)

2012-08-15T23:59:59.000Z

429

Effects of radiation on NO kinetics in turbulent hydrogen/air diffusion flames  

SciTech Connect (OSTI)

The authors describe a coupled radiation and NO kinetics calculation of turbulent hydrogen/air diffusion flame properties. Transport equations for mass, momentum, mixture fraction, enthalpy (sensible + chemical) including gas band radiation, and NO mass fraction are solved. NO kinetics is described by a one step thermal production mechanism. The local temperature is obtained by solving the enthalpy equation taking radiation loss from H{sub 2}O into consideration. Radiation/turbulence and chemical kinetics/turbulence interactions are treated using a clipped Gaussian probability density function (PDF) for the mixture fraction, and a delta PDF for the enthalpy. The source terms in the enthalpy and mass fraction of NO equations are treated using assumed PDF integration over the mixture fraction space. The results of the simulation are compared with existing measurements of the Emission Indices of NO (EINO) in turbulent H{sub 2}/air diffusion flames. The major conclusion of the paper is that coupled turbulence/radiation interactions should be taken into account while computing the EINO.

Sivathanu, Y.R.; Gore, J.P.; Laurendeau, N.M.

1997-07-01T23:59:59.000Z

430

The role of carbon surface diffusion on the growth of epitaxial graphene on SiC.  

SciTech Connect (OSTI)

Growth of high quality graphene films on SiC is regarded as one of the more viable pathways toward graphene-based electronics. Graphitic films form on SiC at elevated temperature because of preferential sublimation of Si. Little is known, however, about the atomistic processes of interrelated SiC decomposition and graphene growth. We have observed the formation of graphene on SiC by Si sublimation in an Ar atmosphere using low energy electron microscopy, scanning tunneling microcopy and atomic force microscopy. This work reveals that the growth mechanism depends strongly on the initial surface morphology, and that carbon diffusion governs the spatial relationship between SiC decomposition and graphene growth. Isolated bilayer SiC steps generate narrow ribbons of graphene, whereas triple bilayer steps allow large graphene sheets to grow by step flow. We demonstrate how graphene quality can be improved by controlling the initial surface morphology specifically by avoiding the instabilities inherent in diffusion-limited growth.

Thurmer, Konrad (Sandia National Laboratories, Livermore, CA); Ohta, Taisuke; Nie, Shu (Sandia National Laboratories, Livermore, CA); Bartelt, Norman Charles (Sandia National Laboratories, Livermore, CA); Kellogg, Gary Lee

2010-03-01T23:59:59.000Z

431

Analysis and experimental study on formation conditions of large-scale barrier-free diffuse atmospheric pressure air plasmas in repetitive pulse mode  

SciTech Connect (OSTI)

Atmospheric air diffuse plasmas have enormous application potential in various fields of science and technology. Without dielectric barrier, generating large-scale air diffuse plasmas is always a challenging issue. This paper discusses and analyses the formation mechanism of cold homogenous plasma. It is proposed that generating stable diffuse atmospheric plasmas in open air should meet the three conditions: high transient power with low average power, excitation in low average E-field with locally high E-field region, and multiple overlapping electron avalanches. Accordingly, an experimental configuration of generating large-scale barrier-free diffuse air plasmas is designed. Based on runaway electron theory, a low duty-ratio, high voltage repetitive nanosecond pulse generator is chosen as a discharge excitation source. Using the wire-electrodes with small curvature radius, the gaps with highly non-uniform E-field are structured. Experimental results show that the volume-scaleable, barrier-free, homogeneous air non-thermal plasmas have been obtained between the gap spacing with the copper-wire electrodes. The area of air cold plasmas has been up to hundreds of square centimeters. The proposed formation conditions of large-scale barrier-free diffuse air plasmas are proved to be reasonable and feasible.

Li, Lee, E-mail: leeli@mail.hust.edu.cn; Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electric and Electronic Engineering, HuaZhong University of Science and Technology (HUST), Wuhan 430074 (China)

2014-01-14T23:59:59.000Z

432

Heat diffusion The objective of this laboratory is for you to use measurements of the diffusion of heat in a material to  

E-Print Network [OSTI]

Heat diffusion Objective The objective of this laboratory is for you to use measurements of the diffusion of heat in a material to enhance your understanding of solutions of the diffusion equation, computerbased oscilloscope. Introduction In MSE 307, we studied the heat capacity of materials. The heat

Braun, Paul

433

Independent Oversight Review, Portsmouth Gaseous Diffusion Plant - April  

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

April 2013 April 2013 Independent Oversight Review, Portsmouth Gaseous Diffusion Plant - April 2013 April 2013 Review of the Integrated Safety Management System Phase I Verification Review at the Portsmouth Gaseous Diffusion Plant The Office of Enforcement and Oversight (Independent Oversight), within the Office of Health, Safety and Security (HSS), conducted an independent review of the U.S. Department of Energy (DOE) Portsmouth/Paducah Project Office (PPPO). The objective of the Independent Oversight review was to evaluate PPPO's conduct of the Integrated Safety Management System (ISMS) Phase I verification review at the Portsmouth Gaseous Diffusion Plant (PORTS). The contractor at PORTS is Fluor-Babcock & Wilcox Portsmouth (FBP). The HSS Office of Safety and Emergency Management Evaluations

434

Paducah Gaseous Diffusion Plant, Construction Worker Screening Project |  

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

Paducah Gaseous Diffusion Plant, Construction Worker Screening Paducah Gaseous Diffusion Plant, Construction Worker Screening Project Paducah Gaseous Diffusion Plant, Construction Worker Screening Project Project Name: Building Trades National Medical Screening Program Covered DOE Site: Paducah Worker Population Served: Construction Workers Principal Investigator: Knut Ringen, DrPH, MHA, MPH Toll-free Telephone: (888) 464-0009 Local Outreach Office: Joe Hudson 1930 North 13th Street Paducah, KY 42001 Website: http://www.btmed.org This project is intended to provide free medical screening to former workers in the building trades (construction workers). The screening targets health problems resulting from exposures, including asbestos, beryllium, cadmium, chromium, lead, mercury, noise, radiation, silica and/or solvents. The project is being carried out by a large group led by

435

Molecular dynamics simulation of hydrogen diffusion in titanium  

National Nuclear Security Administration (NNSA)

9: Computation Physics 9: Computation Physics Atomistic Simulation of Hydrogen Diffusion in Titanium. Alexandr S. Rokhmanenkov, Alexey Yu. Kuksin, and Vladimir V. Stegailov All-Russia Research Institute of Automatics, Moscow 125412, Russia rohmanenkov@gmail.com Summary Study of the behavior of hydrogen in metals and alloys. The study is based on classical molecular dynamics (MD) and density functional theory (DFT) calculations. Study of the behavior of hydrogen in metals and alloys is of great importance due to the practical uses of hydrogen-metal systems for absorption of nuclear radiation, in neutron sources, for storage of hydrogen, or as catalyzers. This work is devoted to atomistic simulation of hydrogen diffusion in titanium hydrides and the effect of stresses and lattice defects on diffusivity.

436

Portsmouth Gaseous Diffusion Plant, Former Production Workers Screening  

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

Portsmouth Gaseous Diffusion Plant, Former Production Workers Portsmouth Gaseous Diffusion Plant, Former Production Workers Screening Projects Portsmouth Gaseous Diffusion Plant, Former Production Workers Screening Projects Project Name: Worker Health Protection Program Covered DOE Site: Portsmouth Worker Population Served: Production Workers Principal Investigator: Jim Frederick Co-Principal Investigator: Steven Markowitz, MD Toll-free Telephone: (888) 241-1199 Local Outreach Office: Jeanne Cisco 2288 Wakefield Mound Road Piketon, OH 45661 Website: http://www.worker-health.org/ This project is conducted by the Unitedsteel Workers in conjunction with Queens College of the City University of New York. The program is being offered as a service to both former and current workers. Free of charge, eligible workers can receive a medical exam, including chest X-ray and

437

Diffusion Enhancement in Core-softened fluid confined in nanotubes  

E-Print Network [OSTI]

We study the effect of confinement in the dynamical behavior of a core-softened fluid. The fluid is modeled as a two length scales potential. This potential in the bulk reproduces the anomalous behavior observed in the density and in the diffusion of liquid water. A series of $NpT$ Molecular Dynamics simulations for this two length scales fluid confined in a nanotube were performed. We obtain that the diffusion coefficient increases with the increase of the nanotube radius for wide channels as expected for normal fluids. However, for narrow channels, the confinement shows an enhancement in the diffusion coefficient when the nanotube radius decreases. This behavior, observed for water, is explained in the framework of the two length scales potential.

José R. Bordin; Alan B. de Oliveira; Alexandre Diehl; Marcia C. Barbosa

2012-08-05T23:59:59.000Z

438

Curved and diffuse interface effects on the nuclear surface tension  

E-Print Network [OSTI]

We redefine the surface tension coefficient for a nuclear Fermi-liquid drop with a finite diffuse layer. Following Gibbs-Tolman concept, we introduce the equimolar radius R_e of sharp surface droplet at which the surface tension is applied and the radius of tension surface R_s which provides the minimum of the surface tension coefficient \\sigma. This procedure allows us to derive both the surface tension and the corresponding curvature correction (Tolman length) correctly for the curved and diffuse interface. We point out that the curvature correction depends significantly on the finite diffuse interface. This fact is missed in traditional nuclear considerations of curvature correction to the surface tension. We show that Tolman's length \\xi is negative for nuclear Fermi-liquid drop. The value of the Tolman length is only slightly sensitive to the Skyrme force parametrization and equals \\xi=-0.36 fm.

V. M. Kolomietz; S. V. Lukyanov; A. I. Sanzhur

2012-01-30T23:59:59.000Z

439

Particle production and nonlinear diffusion in relativistic systems  

E-Print Network [OSTI]

The short parton production phase in high-energy heavy-ion collisions is treated analytically as a nonlinear diffusion process. The initial buildup of the rapidity density distributions of produced charged hadrons within tau_p = 0.25 fm/c occurs in three sources during the colored partonic phase. In a two-step approach, the subsequent diffusion in pseudorapidity space during the interaction time of tau_int = 7-10 fm/c (mean duration of the collision) is essentially linear as expressed in the Relativistic Diffusion Model (RDM) which yields excellent agreement with the data at RHIC energies, and allows for predictions at LHC energies. Results for d+Au are discussed in detail.

Georg Wolschin

2008-09-06T23:59:59.000Z

440

Nano-chemo-mechanical sensor array platform for high-throughput chemical analysis  

Science Journals Connector (OSTI)

We have developed a 2-D multiplexed cantilever array platform for high-throughput nanomechanical chemical sensing and analysis. After coating the cantilevers with alkane thiols having different functional end groups, we have performed vapor phase chemical sensing experiments with toluene and water vapor as targets. To overcome non-uniform responses caused by fabrication and imaging issues, the chemical response of each cantilever is self-calibrated using the thermal response of each cantilever. From these experiments, we could observe chemically induced nanoscale motion of cantilevers for various humidity or vapor concentration levels, and response differentiation with different functional end groups of thiols.

Si-Hyung ”Shawn” Lim; Digvijay Raorane; Srinath Satyanarayana; Arunava Majumdar

2006-01-01T23:59:59.000Z

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


441

Evidence of Multi-Process Matrix Diffusion in a Single Fracturefrom a Field Tracer Test  

SciTech Connect (OSTI)

Compared to values inferred from laboratory tests on matrix cores, many field tracer tests in fractured rock have shown enhanced matrix diffusion coefficient values (obtained using a single-process matrix-diffusion model with a homogeneous matrix diffusion coefficient). To investigate this phenomenon, a conceptual model of multi-process matrix diffusion in a single-fracture system was developed. In this model, three matrix diffusion processes of different diffusion rates were assumed to coexist: (1) diffusion into stagnant water and infilling materials within fractures, (2) diffusion into a degraded matrix zone, and (3) further diffusion into an intact matrix zone. The validity of the conceptual model was then demonstrated by analyzing a unique tracer test conducted using a long-time constant-concentration injection. The tracer-test analysis was conducted using a numerical model capable of tracking the multiple matrix-diffusion processes. The analysis showed that in the degraded zone, a diffusion process with an enhanced diffusion rate controlled the steep rising limb and decay-like falling limb in the observed breakthrough curve, whereas in the intact matrix zone, a process involving a lower diffusion rate affected the long-term middle platform of slowly increasing tracer concentration. The different matrix-diffusion-coefficient values revealed from the field tracer test are consistent with the variability of matrix diffusion coefficient measured for rock cores with different degrees of fracture coating at the same site. By comparing to the matrix diffusion coefficient calibrated using single-process matrix diffusion, we demonstrated that this multi-process matrix diffusion may contribute to the enhanced matrix-diffusion-coefficient values for single-fracture systems at the field scale.

Zhou, Quanlin; Liu, Hui-Hai; Bodvarsson, Gudmundur; Molz, Fred J.

2005-06-11T23:59:59.000Z

442

Falsification of dark energy by fluid mechanics  

E-Print Network [OSTI]

The 2011 Nobel Prize in Physics was awarded for the discovery of accelerating supernovae dimness, suggesting a remarkable change in the expansion rate of the Universe from a decrease since the big bang to an increase, driven by anti-gravity forces of a mysterious dark energy material comprising 70% of the Universe mass-energy. Fluid mechanical considerations falsify both the accelerating expansion and dark energy concepts. Kinematic viscosity is neglected in current standard models of self-gravitational structure formation, which rely on cold dark matter CDM condensations and clusterings that are also falsified by fluid mechanics. Weakly collisional CDM particles do not condense but diffuse away. Photon viscosity predicts superclustervoid fragmentation early in the plasma epoch and protogalaxies at the end. At the plasma-gas transition, the plasma fragments into Earth-mass gas planets in trillion planet clumps (proto-globular-star-cluster PGCs). The hydrogen planets freeze to form the dark matter of galaxies and merge to form their stars. Dark energy is a systematic dimming error for Supernovae Ia caused by dark matter planets near hot white dwarf stars at the Chandrasekhar carbon limit. Evaporated planet atmospheres may or may not scatter light from the events depending on the line of sight.

Carl H. Gibson

2012-03-23T23:59:59.000Z

443

Measuring the thermal diffusivity in a student laboratory  

E-Print Network [OSTI]

The paper describes a method for measuring the thermal diffusivity of materials having a high thermal conductivity. The apparatus is rather simple and low-cost, being therefore suitable in a laboratory for undergraduate students of engineering schools, where several set-ups are often required. A recurrence numerical approach solves the thermal field in the specimen, which is depending on the thermal diffusivity of its material. The numerical method requires the temperature data from two different positions in the specimen, measured by two thermocouples connected to a temperature logger.

Sparavigna, Amelia Carolina

2012-01-01T23:59:59.000Z

444

Diffusion or bounce back in relativistic heavy-ion collisions?  

E-Print Network [OSTI]

The time evolution of pseudorapidity distributions of produced charged hadrons in d+Au collisions at sqrt(s_NN) = 200 GeV is investigated. Results of a nonequilibrium-statistical Relativistic Diffusion Model with three sources are compared with a macroscopic "bounce back" model that does not allow for statistical equilibration at large times, but instead leads to motion reversal. When compared to the data, the results of the diffusion approach are more precise, thus emphasizing that the system is observed to be on its way to thermal equilibrium.

Georg Wolschin; Minoru Biyajima; Takuya Mizoguchi

2008-03-12T23:59:59.000Z

445

Microconvection effects at double?diffusive gradient zone boundaries  

Science Journals Connector (OSTI)

Microconvection in double?diffusive gradient zones is predicted to occur near the zone boundaries because of effects of boundary undulation and temperature modulation caused by impinging thermals in adjacent convecting zones. The equations that govern convective motion in a double?diffusive horizontal slab are solved for boundary conditions that incorporate these effects. Solution of these equations predicts a weakened salinity gradient near the gradient zone boundary between the rising thermals. When the salinity gradient is too weak instability occurs taking the form of descending plumes which are seen in experiments.

John R. Hull; Yojana Katti

1988-01-01T23:59:59.000Z

446

Estimation of effective diffusion coefficients in porous catalysts  

E-Print Network [OSTI]

'usivities were obtained for diR'usion of toluene in zeolites LaZSM-5, FeZSM-5 and BZSM-5. The corrected difl'usivities obtained for the zeolites showed a, dependence on the concentrat1on of' adsorbed species. Uptake experiments were conducted f' or studying... diffusion of n- hexane in a type II crystalline titanate, and the intracrystalline diffusivities were found to be independent of the adsorbate concentration. sv ACKNOWLEDGEMENT I would like to acknowledge my research advisor, Dr. R. G. Anthony...

Kulkarni, Shrikant Ulhas

2012-06-07T23:59:59.000Z

447

Crossover from diffusive to ballistic transport properties in magnetic multilayers  

Science Journals Connector (OSTI)

We develop a theoretical model for computing the spin-dependent transport properties of magnetic multilayers in the presence of ballistic scattering at the interfaces and diffusive scattering within the layers for currents perpendicular to the plane of the layers. The local chemical potentials are found to be momentum and spin dependent in the vicinity of regions with ballistic scattering. We have derived the approximate macroscopic equations from the Boltzmann equation by taking into account both ballistic and diffusive scattering. With these equations, realistic data of the reflection coefficients from ab initio calculations can be explicitly included in computing magnetotransport properties. We apply our formulation to a number of interesting magnetic multilayer structures.

Y. -N. Qi and S. Zhang

2002-05-17T23:59:59.000Z

448

Discrepancies in Shortwave Diffuse Measured and Modeled Irradiances in Antarctica  

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

Discrepancies in Shortwave Diffuse Measured and Discrepancies in Shortwave Diffuse Measured and Modeled Irradiances in Antarctica A. Payton, P. Ricchiazzi, and C. Gautier University of California Santa Barbara, California D. Lubin Scripps Scripps Institution of Oceanography La Jolla, California Introduction Measurements of clear-sky shortwave (SW) radiation at the surface show discrepancies between measurements and model simulations, but only for certain measurements across time and space. Most of the observations entail broadband measurements. A spectral and spatial analysis of the occurrence of this discrepancy may lend insight into the responsible processes. Langley calibrated multi-filter rotating shadowband radiometer (MFRSR) measurements collected at the Antarctic coastline reveal significant

449

MECHANICAL ENGINEERING UNDERGRADUATE HONORS THESIS  

E-Print Network [OSTI]

, when two bound copies are to be submitted to the Mechanical Engineering Services Office #12;PLEASE Mechanical Engineering Student Services: ¨ Application Approved ¨ Application Denied Signature of UGMECHANICAL ENGINEERING UNDERGRADUATE HONORS THESIS The Department of Mechanical Engineering

Prinz, Friedrich B.

450

STANFORD UNIVERSITY MECHANICAL ENGINEERING DEPARTMENT  

E-Print Network [OSTI]

20062007 Mechanical Engineering Student Services Building 530, Room 125 (650) 7257695 FAX (650) 7234882STANFORD UNIVERSITY MECHANICAL ENGINEERING DEPARTMENT GRADUATE STUDENT HANDBOOK Academic Year Revised 9/06 #12;MECHANICAL ENGINEERING GRADUATE STUDENT HANDBOOK 20062007 TABLE OF CONTENTS (Clickable

Prinz, Friedrich B.

451

Mechanical Behavior of Indium Nanostructures  

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

Mechanical Behavior of Indium Nanostructures Mechanical Behavior of Indium Nanostructures Print Wednesday, 26 May 2010 00:00 Indium is a key material in lead-free solder...

452

Comprehensive mechanisms for combustion chemistry: Experiment, modeling, and sensitivity analysis  

SciTech Connect (OSTI)

This research program is an integrated experimental/numerical effort to study pyrolysis and oxidation reactions and mechanisms for small-molecule hydrocarbon structures under conditions representative of combustion environments. The experimental aspects of the work are conducted in large diameter flow reactors, at pressures from one to twenty atmospheres, temperatures from 550 K to 1200 K, and with observed reaction times from 10{sup {minus}2} to 5 seconds. Gas sampling of stable reactant, intermediate, and product species concentrations provides not only substantial definition of the phenomenology of reaction mechanisms, but a significantly constrained set of kinetic information with negligible diffusive coupling. Analytical techniques used for detecting hydrocarbons and carbon oxides include gas chromatography (GC), and gas infrared (NDIR) and FTIR methods are utilized for continuous on-line sample detection of light absorption measurements of OH have also been performed in an atmospheric pressure flow reactor (APFR), and a variable pressure flow (VPFR) reactor is presently being instrumented to perform optical measurements of radicals and highly reactive molecular intermediates. The numerical aspects of the work utilize zero and one-dimensional pre-mixed, detailed kinetic studies, including path, elemental gradient sensitivity, and feature sensitivity analyses. The program emphasizes the use of hierarchical mechanistic construction to understand and develop detailed kinetic mechanisms. Numerical studies are utilized for guiding experimental parameter selections, for interpreting observations, for extending the predictive range of mechanism constructs, and to study the effects of diffusive transport coupling on reaction behavior in flames. Modeling using well defined and validated mechanisms for the CO/H{sub 2}/oxidant systems.

Dryer, F.L.; Yetter, R.A. [Princeton Univ., NJ (United States)

1993-12-01T23:59:59.000Z

453

1D to 3D diffusion-reaction kinetics of defects in crystals  

Science Journals Connector (OSTI)

Microstructural features evolving in crystalline solids from diffusion-reaction kinetics of mobile components depend crucially on the dimension of the underlying diffusion process which is commonly assumed to be three-dimensional (3D). In metals, irradiation-induced displacement cascades produce clusters of self-interstitials performing 1D diffusion. Changes between equivalent 1D diffusion paths and transversal diffusion result in diffusion-reaction kinetics between one and three dimensions. An analytical approach suggests a single-variable function (master curve) interpolating between the 1D and 3D limiting cases. The analytical result is fully confirmed by kinetic Monte Carlo simulations.

H. Trinkaus; H. L. Heinisch; A. V. Barashev; S. I. Golubov; B. N. Singh

2002-08-30T23:59:59.000Z

454

Acoustic hemostasis: Underlying mechanisms  

Science Journals Connector (OSTI)

Cessation of hemorrhage using extrinsic interventional methods is possible with delivery of energy to bleeding tissues i.e. cauterization. High intensity focused ultrasound (HIFU) is one such method with significant advantages of delivering high levels of energy to well?defined regions of deep?seated tissues even during profuse bleeding. The physical mechanisms involved in this process include thermal and mechanical effects of HIFU leading to various biological effects. Our results using HIFU devices of 1–5 MHz and focal derated intensities of 1 000–10 000 W/cm2 in solid organs such as liver spleen and kidneys and major and minor blood vessels show that temperature of targeted tissues reaches 70–100°C within seconds with formation of microbubbles approximately 5??200 ? in size and concentration of 100 bubbles/mm3. It appears that boiling of interstitial fluids and blood and acoustic cavitation are both involved. The biological effects include coagulative necrosis mechanical disruption of tissue structure potentially leading to release of tissue factors enhancing the coagulation coagulum and thrombus formation at a wound site tissue fusion via collagen and elastin remodeling and fibrin plug formation with minimal damage of the surrounding tissues. These mechanisms appear to provide an effective and safe method of hemorrhage control. [Work supported by NIH DoD NSBRI.

Shahram Vaezy; Lawrence Crum; Steve Carter; Grant O’Keefe; Vesna Zderic; Roy Martin; Riyad Karmy?Jones

2007-01-01T23:59:59.000Z

455

Thermodynamics and statistical mechanics  

Science Journals Connector (OSTI)

... IN this book, Professor Landsberg brings together thermodynamics and statistical mechanics to provide a coherent account of these interrelated branches of physical theory ... side usually result in the essential structures of both becoming obscured. The value of classical thermodynamics lies in what it can do without invoking microscopic models and it is best learnt ...

C.J. Adkins

1979-12-20T23:59:59.000Z

456

Residential Mechanical Precooling  

SciTech Connect (OSTI)

This research conducted by the Alliance for Residential Building Innovation team evaluated mechanical air conditioner pre-cooling strategies in homes throughout the United States. EnergyPlus modeling evaluated two homes with different performance characteristics in seven climates. Results are applicable to new construction homes and most existing homes built in the last 10 years, as well as fairly efficient retrofitted homes.

German, A.; Hoeschele, M.

2014-12-01T23:59:59.000Z

457

Skin cancer detection by oblique-incidence diffuse reflectance spectroscopy  

E-Print Network [OSTI]

Skin cancer is the most common form of cancer and it is on the rise. If skin cancer is diagnosed early enough, the survival rate is close to 90%. Oblique-incidence diffuse reflectance (OIR) spectroscopy offers a technology that may be used...

Smith, Elizabeth Brooks

2009-05-15T23:59:59.000Z

458

AN ANISOTROPIC DIFFUSION APPROACH FOR EARLY DETECTION OF BREAST CANCER  

E-Print Network [OSTI]

AN ANISOTROPIC DIFFUSION APPROACH FOR EARLY DETECTION OF BREAST CANCER Marius George LINGURARU, Oxford OX2 7BZ, United Kingdom mglin@robots.ox.ac.uk Abstract: The prevalence of breast cancer must provide effective clinical methods to detect cancer and improve life expectancy. Considerable

Paris-Sud XI, Université de

459

Modelling Electrical Car Diffusion Based on Agent Tao Zhang, 3  

E-Print Network [OSTI]

Modelling Electrical Car Diffusion Based on Agent 1 Lei Yu, ,2 Tao Zhang, 3 Siebers Peer-Ola, 4 to include things like car parking charges, price of electrical car, energy awareness and word of mouth parking rates and other incentives on the uptake of electrical cars. The goal of this case study

Aickelin, Uwe

460

LE JOURNAL DE PHYSIQUE THORIE DU TRANAGE MAGNTIQUE DE DIFFUSION  

E-Print Network [OSTI]

LE JOURNAL DE PHYSIQUE ET LE RADIUM TH�ORIE DU TRA�NAGE MAGN�TIQUE DE DIFFUSION Par M. LOUIS N�EL. Laboratoire d'�lectrostatique et de Physique du Métal, Grenoble. Sommaire. - Après avoir rappelé l LE JOURNAL DE PHYSIQUE ILT

Boyer, Edmond

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


461

DARK MATTER Tracing the "Cosmic Web" with Diffuse Gas  

E-Print Network [OSTI]

1 DARK MATTER STARS GAS NEUTRAL HYDROGEN Tracing the "Cosmic Web" with Diffuse Gas Quasar Quasar Absorption Lines Keck/HIRES Quasar Spectrum Observer baryons dark matter potential isotropic UV only on and the radiation field intensity... H I #12;5 GOAL: the primordial dark matter power spectrum

Steidel, Chuck

462

The data diffusion space for parallel computing in clusters  

Science Journals Connector (OSTI)

The data diffusion space (DDS) is an all-software shared address space for parallel computing on distributed memory platforms. It is an extra address space to that of each process running a parallel application under the SPMD (Single Program Multiple ...

Jorge Buenabad-Chávez; Santiago Domínguez-Domínguez

2005-08-01T23:59:59.000Z

463

Diffuse scattering and partial disorder in complex structures  

Science Journals Connector (OSTI)

This review discusses the state of the field of single-crystal diffuse scattering (SCDS), including detectors, data collection and the modelling techniques. High quality, three-dimensional volumes of SCDS data can now be collected at synchrotron light sources, allowing increasingly detailed and quantitative analyses to be undertaken.

Welberry, T.R.

2014-10-28T23:59:59.000Z

464

Modelling precipitation of niobium carbide in austenite: multicomponent diffusion, capillarity,  

E-Print Network [OSTI]

Modelling precipitation of niobium carbide in austenite: multicomponent diffusion, capillarity, and coarsening N. Fujita and H. K. D. H. Bhadeshia The growth of niobium carbide in austenite involves for the overall transformation kinetics of niobium carbide precipitation in austenite that takes into account

Cambridge, University of

465

Graphene: From Diffusive to Ultraclean-Interacting Systems  

E-Print Network [OSTI]

Graphene: From Diffusive to Ultraclean-Interacting Systems Inauguraldissertation zur Erlangung der. Introduction 1 2. The Properties of Graphene 3 2.1. Band Structure of Graphene . . . . . . . . . . . . . . . . . . . . . 3 2.1.1. Single Layer Graphene . . . . . . . . . . . . . . . . . . . . 3 2.1.2. Bilayer Graphene

Amrhein, Valentin

466

Magnetic-diffusion-driven shear instability of solar flux tubes  

Science Journals Connector (OSTI)

......photosphere and chromosphere. MHD|waves|Sun: photosphere...variety of magnetohydrodynamic (MHD) waves are generated in the...Fig.-3). Figure 3. Above diagram depicts the growth rate against...diffusive medium. A. Ideal MHD: in this limit, , i.e. and......

B. P. Pandey; Mark Wardle

2013-01-01T23:59:59.000Z

467

Geometry-induced asymmetric diffusion Robert S. Shaw*  

E-Print Network [OSTI]

channels Asymmetric diffusion appears in studies of ion transport across membranes (1 that ions can pass through a membrane more readily in one direction than the other. We demonstrate here constraints may play a role in common biological contexts such as membrane ion channels. asymmetric pores

Texas at Austin. University of

468

Dynamic physiological modeling for functional diffuse optical tomography  

E-Print Network [OSTI]

,c and David A. Boasa a Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging and brain that reflect competing metabolic demands and cardiovascular dynamics. The diffuse nature of near- namic response. In this paper, we present a linear state-space model for DOT analysis that models

469

Multiple copy distillation and purification of phase diffused squeezed states  

E-Print Network [OSTI]

We provide a detailed theoretical analysis of multiple copy purification and distillation protocols for phase diffused squeezed states of light. The standard iterative distillation protocol is generalized to a collective purification of an arbitrary number of N copies. We also derive a semi-analytical expression for the asymptotic limit of the iterative distillation and purification protocol and discuss its properties.

Petr Marek; Jaromir Fiurasek; Boris Hage; Alexander Franzen; James DiGugliemo; Roman Schnabel

2007-08-10T23:59:59.000Z

470

On collisional diffusion in a stochastic magnetic field  

SciTech Connect (OSTI)

The effect of particle collisions on the transport in a stochastic magnetic field in tokamaks is investigated. The model of resonant magnetic perturbations generated by external coils at the plasma edge is used for the stochastic magnetic field. The particle collisions are simulated by a random walk process along the magnetic field lines and the jumps across the field lines at the collision instants. The dependencies of the local diffusion coefficients on the mean free path ?{sub mfp}, the diffusion coefficients of field lines D{sub FL}, and the collisional diffusion coefficients, ?{sub ?} are studied. Based on these numerical data and the heuristic arguments, the empirical formula, D{sub r}=?{sub ?}+v{sub ||}D{sub FL}/(1+L{sub c}/?{sub mfp}), for the local diffusion coefficient is proposed, where L{sub c} is the characteristic length of order of the connection length l{sub c}=?qR{sub 0}, q is the safety factor, R{sub 0} is the major radius. The formula quite well describes the results of numerical simulations. In the limiting cases, the formula describes the Rechester-Rosenbluth and Laval scalings.

Abdullaev, S. S. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung - Plasmaphysik, EURATOM Association, 52425 Jülich (Germany)] [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung - Plasmaphysik, EURATOM Association, 52425 Jülich (Germany)

2013-08-15T23:59:59.000Z

471

Single molecule tracking of heterogeneous diffusion Jianshu Cao  

E-Print Network [OSTI]

showing no sign of heterogeneities in the ensemble measurement of the diffusion constant. The signature liquids, and colloidal fluids 21­25 . Zwanzig studied percolation in a dynamic disordered system using in the membrane structure 33,34 . Some proteins are transiently confined to small island domains bounded

Cao, Jianshu

472

Numerical study on the validity of the diffusion approximation  

E-Print Network [OSTI]

of photons can be accurately modeled by the radiative transport equation (RTE).9,10 Because and the radiative transport as implemented by Monte Carlo simulation in the cases of point and ball sources. Our of the difficulties in handling the RTE directly, the diffusion approximation to the transport equation has been

Virginia Tech

473

Generalized diffusion model in optical tomography with clear layers  

E-Print Network [OSTI]

transport equation that describes the den- sity of photons in the phase space, i.e., as a function of po increasingly often.9 For computational savings an approximation to radiative transport is often preferred solve phase-space transport equa- tions instead of the inaccurate diffusion equations.12,16 A large

Ren, Kui

474

Inwardly Rotating Spiral Waves in a Reaction-Diffusion System  

E-Print Network [OSTI]

are nonpolar, are produced in the water droplets and can diffuse into the oil phase. Communication between spirals found in the BZ system dispersed in water droplets of a water-in-oil microemulsion oscillatory BZ reaction in water-in-oil AOT microemulsion (BZ-AOT system) (16, 19, 20). This system consists

Epstein, Irving R.

475

DIFFUSION INELASTIQUE DES AIEUTRONS ET ONDES DE SPIN  

E-Print Network [OSTI]

measured in the three principal symmetry directions by neutron inelastic scattering.The spin wave of neutrons C(Eogo)scattered by a spin wave of energy Eo and wave vector qo satisfies the following diffusion inklastiquedes neutrons. On a trouvB que les relations de dispersion des ondes de spin

Boyer, Edmond

476

High phosphorous doped germanium: Dopant diffusion and modeling  

E-Print Network [OSTI]

The in situ n-type doping of Ge thin films epitaxial grown on Si substrates is limited to 1?×?10[superscript 19]?cm[superscript ?3] by the phosphorous out-diffusion during growth at 600?°C. By studying the phosphorous ...

Cai, Yan

477

A reaction-diffusion model of the human brain development  

Science Journals Connector (OSTI)

The anatomical variability of the human brain folds remains an unclear and challenging issue. Several hypotheses coexist for explaining the rapid development of cortical sulci and it is clear that understanding their variability would improve the comparison ... Keywords: brain development, folding, reaction-diffusion equations

Julien Lefèvre; Jean-François Mangin

2010-04-01T23:59:59.000Z

478

Scale dependence of intragranular porosity, tortuosity, and diffusivity  

E-Print Network [OSTI]

may be in the ground for years or decades before they are discovered and targeted for remediation [e pores and flowing water is a recognized but poorly understood contributor to dispersion. Intragranular porosity, tortuosity, and diffusivity, Water Resour. Res., 46, W06513, doi:10.1029/2009WR008183. 1

Hu, Qinhong "Max"

479

Energy Department Selects Deactivation Contractor for Paducah Gaseous Diffusion Plant  

Broader source: Energy.gov [DOE]

LEXINGTON, Ky. – The U.S. Department of Energy (DOE) today awarded a Task Order under the Nationwide Environmental Management ID/IQ Unrestricted Contract to Fluor Federal Services, Inc. for deactivation activities at the Paducah Gaseous Diffusion Plant (GDP) in Paducah, Kentucky, which is currently leased to the United States Enrichment Corporation (USEC).

480

Robust Variational Estimation of PDF functions from Diffusion MR Signal  

E-Print Network [OSTI]

field distortion QBI: Funk-Radon transform [Tuch04] Radial projection of the PDF Orientation Density;Diffusion MRI: Brownian Motion a: Brownian motion of water molecules b: Constraints due to body internal(2||q ||||p||) (k) Table: A non exhaustive list of PDF caracteristics G and their associated projection

Brun, Chez Luc

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


481

Self-similar and charged spheres in the diffusion approximation  

E-Print Network [OSTI]

We study spherical, charged and self--similar distributions of matter in the diffusion approximation. We propose a simple, dynamic but physically meaningful solution. For such a solution we obtain a model in which the distribution becomes static and changes to dust. The collapse is halted with damped mass oscillations about the absolute value of the total charge.

Barreto, W

1999-01-01T23:59:59.000Z

482

Does the photon-diffusion coefficient depend on absorption?  

E-Print Network [OSTI]

Does the photon-diffusion coefficient depend on absorption? T. Durduran and A. G. Yodh Department independent of absorption, i.e., D0 v/3 s . After presentation of the general theoretical arguments underlying this assertion, Monte Carlo simulations are performed and explicitly reveal that the absorption- independent

Boas, David

483

Sorption and Diffusion of Organic Vapors in Two Fluoroelastomers  

E-Print Network [OSTI]

Sorption and Diffusion of Organic Vapors in Two Fluoroelastomers PING WANG,* NATHANIEL S. SCHNEIDER of II in polar liquids: over 100% (wt/wt) in two ketones and a phosphate ester. Sorption isotherms deter determined from sorption kinetics, corrected for nonisothermal effects, and converted to solvent self

Wang, Ping

484

Template-Based Tractography for Clinical Neonatal Diffusion Imaging Data  

E-Print Network [OSTI]

Los Angeles, 4650 Sunset Blvd, Los Angeles-CA, USA; dParietal Research Team, INRIA Parc Orsay difficult to define structure by means of diffusion profiles. Here, we introduce a post-processing method to the difficulties associated to keeping a non-sedated neonate static into the scanner the desired time

Paris-Sud XI, Université de

485

Measurement of the Diffusion Coefficient of Radium A  

Science Journals Connector (OSTI)

... Radon decays by alpha emission, with a half-life of 3825 days, to form radium ... on the aerosol concentration and on the diffusion coefficient. Similar effects occur with other unattached radon progeny, the most important being 214Pb, called radium B, and 214Bi, called radium ...

OTTO G. RAABE

1968-03-23T23:59:59.000Z

486

Full-wavelet approach for fluorescence diffuse optical tomography  

E-Print Network [OSTI]

Full-wavelet approach for fluorescence diffuse optical tomography with structured illumination Leonardo da Vinci 32, I-20133 Milan, Italy 3 Centre for Medical Image Computing, University College London); published October 28, 2010 We present a fast reconstruction method for fluorescence optical tomography

Boyer, Edmond

487

Advective diffusive/dispersive transport in geochemical processes  

SciTech Connect (OSTI)

Comprehensive understanding of chemical transport in response to fluid flow and diffusion in geologic processes requires thermodynamic and transport properties of a wide variety of aqueous species at the temperature and pressure of interest, as well as mass transfer computer codes that provide simultaneously for fluid flow, diffusion, dispersion, homogeneous chemical reactions, and mineral solubilities. As a result of research carried out with support from DOE in prior years of this grant, considerable progress has been made in developing computer codes to calculate advective-dispersive-diffusional transport at both high and low pressures and temperatures. These codes have become highly sophisticated, but their application to geochemical processes is limited by the availability of thermodynamic and transport data for the major solute species in the aqueous phase. Over the past three years, research has been directed primarily toward characterizing the thermodynamic behavior of concentrated supercritical aqueous electrolyte solutions and predicting the diffusion coefficients of organic species in oil field brines. Related research has been concerned with characterizing the growth rate of hydrothermal alteration zones and assessing the relative importance of aqueous diffusion and heterogeneous reactions at mineral surfaces in geochemical processes. 103 refs., 12 figs.

Helgeson, H.C.

1991-05-28T23:59:59.000Z

488

MaximumA Posteriori Estimation of Transient Enhanced Diffusion Energetics  

E-Print Network [OSTI]

into the wafer. However, ion implantation causes lattice damage, producing junctions with high sheet resistance. 2000 . Here, a comprehensive TED model is developed combin- Zing elementary physicochemical processes continuity equations describing Fickian diffusion and electric drift motion, and formation and Zannihilation

Braatz, Richard D.

489

Department of Mechanical Engineering "From Compliant Mechanisms to  

E-Print Network [OSTI]

such as 3D printing with materials specialized in electro- mechanical sensing and actuation in addition

Militzer, Burkhard

490

Program Transformation Mechanics A Classification of Mechanisms for Program Transformation  

E-Print Network [OSTI]

Program Transformation Mechanics A Classification of Mechanisms for Program Transformation with a Survey of Existing Transformation Systems Jonne van Wijngaarden Eelco Visser UU-CS-2003-048 Institute Transformation Mechanics A Classification of Mechanisms for Program Transformation with a Survey of Existing

Utrecht, Universiteit

491

MECHANICAL ENGINEERING 121 Department of Mechanical Engineering (MEE)  

E-Print Network [OSTI]

MECHANICAL ENGINEERING 121 Department of Mechanical Engineering (MEE) *Available for general education credit. The Department of Mechanical Engineering offers an upper- division curriculum which leads to a B.S. in mechanical engineering. The curriculum is based on a strong foundation of fundamental

Kostic, Milivoje M.

492

Mechanical engineering Mechanical engineering is about solving problems, designing processes,  

E-Print Network [OSTI]

Mechanical engineering Mechanical engineering is about solving problems, designing processes, and making products to improve the quality of human life and shape the economy. Mechanical engineers apply the principles of physics, mathematics, computing and practical skills to design mechanical systems and artefacts

Waikato, University of

493

114 MECHANICAL ENGINEERING Department of Mechanical Engineering (MEE)  

E-Print Network [OSTI]

114 MECHANICAL ENGINEERING Department of Mechanical Engineering (MEE) *Available for general education credit. The Department of Mechanical Engineering offers an upper- division curriculum which leads to a B.S. in mechanical engineering. The curriculum is based on a strong foundation of fundamental

Kostic, Milivoje M.

494

Mechanical Engineering Department Seminar Series  

E-Print Network [OSTI]

Mechanical Engineering Department Seminar Series Rational Mechanics of Viral Shells: Is Continuum Theory a Stretch? William S. Klug Associate Professor, Mechanical & Aerospace Engineering, University-assembly. The capacity of these shells to respond structurally and mechanically to physical and chemical stimuli also

Eustice, Ryan

495

07SCHOOL OF MECHANICAL ENGINEERING  

E-Print Network [OSTI]

, mechanical with nuclear engineering, and medical engineering. Engineers qualified in all these areas play MECHANICAL ENGINEERING MECHANICAL WITH NUCLEAR ENGINEERING MEDICAL ENGINEERING OTHER COURSES TO CONSIDER Entryrequirementsandhowtoapply Modules MedicalEngineering(MEng,BEng) MechanicalwithNuclearEngineering(MEng,BEng) MechanicalEngineering

Dimitrova, Vania

496

Mechanical Operations and Maintenance  

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

Holiday Work Status Holiday Work Status Mechanical Operations & Maintenance Group APS Storage Ring Magnets The Advanced Photon Source (APS) at the Argonne National Laboratory is a national synchrotron-radiation research facility funded by the U.S. Department of Energy. Using high-brilliance x-ray beams from the APS, an international community of scientists conducts forefront basic and applied research in the fields of material science, biological science, physics, chemistry, environmental, geophysical and planetary science. The 1.1-km circumference APS facility consists of several major subsystems including magnets, vacuum chambers, radio-frequency cavities, diagnostics instrumentation, x-ray absorbers and apertures, and cooling water subsystems. Each of these subsystems contains hundreds of mechanical

497

Mechanics of collective unfolding  

E-Print Network [OSTI]

Mechanically induced unfolding of passive crosslinkers is a fundamental biological phenomenon encountered across the scales from individual macro-molecules to cytoskeletal actin networks. In this paper we study a conceptual model of athermal load-induced unfolding and use a minimalistic setting allowing one to emphasize the role of long-range interactions while maintaining full analytical transparency. Our model can be viewed as a description of a parallel bundle of N bistable units confined between two shared rigid backbones that are loaded through a series spring. We show that the ground states in this model correspond to synchronized, single phase configurations where all individual units are either folded or unfolded. We then study the fine structure of the wiggly energy landscape along the reaction coordinate linking the two coherent states and describing the optimal mechanism of cooperative unfolding. Quite remarkably, our study shows the fundamental difference in the size and structure of the folding-u...

Caruel, M; Truskinovsky, L

2015-01-01T23:59:59.000Z

498

On the Estimation of Lagrangian Diffusivity: Influence of Nonstationary Mean Flow  

Science Journals Connector (OSTI)

Eddy–mean flow decomposition is crucial to the estimation of Lagrangian diffusivity based on drifter data. Previous studies have shown that inhomogeneous mean flow induces shear dispersion that increases the estimated diffusivity with time. In the ...

Yu-Kun Qian; Shiqiu Peng; Chang-Xia Liang; Rick Lumpkin

2014-10-01T23:59:59.000Z

499

Transition to hexagonal pattern under the variation of intrinsic length scales of a reaction diffusion system  

Science Journals Connector (OSTI)

The intrinsic length scales of a reaction diffusion system (Gierer-Meinhardt model) is varied by quasi-statically changing the diffusion constant of the activator and a transition from rolls to hexagon is dete...

J. Sienkiewicz; A. Bhattacharyay

2004-07-01T23:59:59.000Z

500

Experimental investigation on the energy-saving diffuser of a main fan  

Science Journals Connector (OSTI)

The main fan diffuser in a coal mine is an energy-recycling equipment with a dynamic energy loss for the main fan. Engineering practices ... are irrational. To solve the problem, an energy-saving diffuser is desi...

Shi-qiang Chen; Hai-qiao Wang…

2012-03-01T23:59:59.000Z