National Library of Energy BETA

Sample records for vapor-phase diffusion mechanisms

  1. Vapor phase modifiers for oxidative coupling

    DOE Patents [OSTI]

    Warren, Barbara K. (Charleston, WV)

    1991-01-01

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

  2. Vapor phase modifiers for oxidative coupling

    DOE Patents [OSTI]

    Warren, B.K.

    1991-12-17

    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.

  3. The role of polymer formation during vapor phase lubrication...

    Office of Scientific and Technical Information (OSTI)

    The role of polymer formation during vapor phase lubrication of silicon. Citation Details In-Document Search Title: The role of polymer formation during vapor phase lubrication of...

  4. Monitoring of vapor phase polycyclic aromatic hydrocarbons

    DOE Patents [OSTI]

    Vo-Dinh, Tuan; Hajaligol, Mohammad R.

    2004-06-01

    An apparatus for monitoring vapor phase polycyclic aromatic hydrocarbons in a high-temperature environment has an excitation source producing electromagnetic radiation, an optical path having an optical probe optically communicating the electromagnetic radiation received at a proximal end to a distal end, a spectrometer or polychromator, a detector, and a positioner coupled to the first optical path. The positioner can slidably move the distal end of the optical probe to maintain the distal end position with respect to an area of a material undergoing combustion. The emitted wavelength can be directed to a detector in a single optical probe 180.degree. backscattered configuration, in a dual optical probe 180.degree. backscattered configuration or in a dual optical probe 90.degree. side scattered configuration. The apparatus can be used to monitor an emitted wavelength of energy from a polycyclic aromatic hydrocarbon as it fluoresces in a high temperature environment.

  5. MODELLING AND SIMULATION OF LIQUID-VAPOR PHASE TRANSITION

    E-Print Network [OSTI]

    Faccanoni, Gloria

    . (,) P pressure law. G. Faccanoni DNS OF LIQUIDE-VAPOR PHASE TRANSITION 6 / 23 #12;Model Numerical Method. (,) P pressure law. G. Faccanoni DNS OF LIQUIDE-VAPOR PHASE TRANSITION 6 / 23 #12;Model Numerical Method Vapor = 0 x = 0 = 1Fictive fluid 0 pressure law

  6. Vapor Phase Synthesis and Characterization of -FeSi Nanowires

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    Vapor Phase Synthesis and Characterization of - FeSi Nanowires Lian Ouyang, Elizabeth S. Thrall, Mandar M. Deshmukh, and Hongkun Park Over the past decade, one-dimensional inorganic nanostructures have emerged as promising materials for fundamental studies and possible technological applications.[1

  7. MEMS Lubrication by In-Situ Tribochemical Reactions From the Vapor Phase.

    SciTech Connect (OSTI)

    Dugger, Michael T.; Asay, David B.; Kim, Seong H.

    2008-01-01

    Vapor Phase Lubrication (VPL) of silicon surfaces with pentanol has been demonstrated. Two potential show stoppers with respect to application of this approach to real MEMS devices have been investigated. Water vapor was found to reduce the effectiveness of VPL with alcohol for a given alcohol concentration, but the basic reaction mechanism observed in water-free environments is still active, and devices operated much longer in mixed alcohol and water vapor environments than with chemisorbed monolayer lubricants alone. Complex MEMS gear trains were successfully lubricated with alcohol vapors, resulting in a factor of 104 improvement in operating life without failure. Complex devices could be made to fail if operated at much higher frequencies than previously used, and there is some evidence that the observed failure is due to accumulation of reaction products at deeply buried interfaces. However, if hypothetical reaction mechanisms involving heated surfaces are valid, then the failures observed at high frequency may not be relevant to operation at normal frequencies. Therefore, this work demonstrates that VPL is a viable approach for complex MEMS devices in conventional packages. Further study of the VPL reaction mechanisms are recommended so that the vapor composition may be optimized for low friction and for different substrate materials with potential application to conventionally fabricated, metal alloy parts in weapons systems. Reaction kinetics should be studied to define effective lubrication regimes as a function of the partial pressure of the vapor phase constituent, interfacial shear rate, substrate composition, and temperature.

  8. Liquid-phase compositions from vapor-phase analyses

    SciTech Connect (OSTI)

    Davis, W. Jr. ); Cochran, H.D. )

    1990-02-01

    Arsenic normally is not considered to be a contaminant. However, because arsenic was found in many cylinders of UF{sub 6}, including in corrosion products, a study was performed of the distribution of the two arsenic fluorides, AsF{sub 3} and AsF{sub 5}, between liquid and vapor phases. The results of the study pertain to condensation or vaporization of liquid UF{sub 6}. This study includes use of various experimental data plus many extrapolations necessitated by the meagerness of the experimental data. The results of this study provide additional support for the vapor-liquid equilibrium model of J.M. Prausnitz and his coworkers as a means of describing the distribution of various impurities between vapor and liquid phases of UF{sub 6}. Thus, it is concluded that AsF{sub 3} will tend to concentrate in the liquid phase but that the concentration of AsF{sub 5} in the vapor phase will exceed its liquid-phase concentration by a factor of about 7.5, which is in agreement with experimental data. Because the weight of the liquid phase in a condensation operation may be in the range of thousands of times that of the vapor phase, most of any AsF{sub 5} will be in the liquid phase in spite of this separation factor of 7.5. It may also be concluded that any arsenic fluorides fed into a uranium isotope separation plant will either travel with other low-molecular-weight gases or react with materials present in the plant. 25 refs., 3 figs., 6 tabs.

  9. Diffusive Shock Acceleration: the Fermi Mechanism

    E-Print Network [OSTI]

    Matthew G. Baring

    1997-11-16

    The mechanism of diffusive Fermi acceleration at collisionless plasma shock waves is widely invoked in astrophysics to explain the appearance of non-thermal particle populations in a variety of environments, including sites of cosmic ray production, and is observed to operate at several sites in the heliosphere. This review outlines the principal results from the theory of diffusive shock acceleration, focusing first on how it produces power-law distributions in test-particle regimes, where the shock dynamics are dominated by the thermal populations that provide the seed particles for the acceleration process. Then the importance of non-linear modifications to the shock hydrodynamics by the accelerated particles is addressed, emphasizing how these subsequently influence non-thermal spectral formation.

  10. Vapor phase elemental sulfur amendment for sequestering mercury in contaminated soil

    DOE Patents [OSTI]

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

    2014-07-08

    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.

  11. AlGaAsSb/GaSb Distributed Bragg Reflectors Grown by Organometallic Vapor Phase Epitaxy

    SciTech Connect (OSTI)

    C.A. Wang; C.J. Vineis; D.R. Calawa

    2002-02-13

    The first AlGaAsSb/GaSb quarter-wave distributed Bragg reflectors grown by metallic vapor phase epitaxy are reported. The peak reflectance is 96% for a 10-period structure.

  12. Vapor-Phase Metalation by Atomic Layer Deposition in a Metal-Organic Framework

    E-Print Network [OSTI]

    Vapor-Phase Metalation by Atomic Layer Deposition in a Metal- Organic Framework Joseph E. Mondloch introduce a new synthetic strategy capable of metallating MOFs from the gas phase: atomic layer deposition and in some instances host- guest interactions may lead to unstable metal@MOFs. Atomic layer deposition (ALD

  13. Stimulated Emission from As-grown GaN Hexagons by Selective Area Growth Hydride Vapor Phase Epitaxy

    E-Print Network [OSTI]

    Stimulated Emission from As-grown GaN Hexagons by Selective Area Growth Hydride Vapor Phase Epitaxy Engineering and the Photonics Center, Boston University, 8 Saint Mary's St., Boston, MA 02215-2421, USA R hydride vapor phase epitaxy. We found the threshold for bulk stimulated emission to be 3.4 MW cm2

  14. Engineering work plan for tank 241-C-103 vapor phase characterization (ECN 613188). Revision 1

    SciTech Connect (OSTI)

    Conrad, R.B.

    1994-10-05

    The tasks described by this work plan have been completed. The purpose of this revision it to document what actually occurred during the performance of this work plan. The scope was and is limited to phases 1 and 2 as described in the program plan, revision 1. Phases 1 and 2 include the tank 241-C-103 (C-103) vapor. For economic and as low as reasonably achievable (ALARA) reasons, we will limit our scope to characterize the C-103 vapor phase for the categories that could be expected to impact facility worker safety from a toxicological and flammability standpoint. In anticipation that a vapor treatment system may be required, categories necessary for design will also be included. It will be the intent of the C-103 vapor characterization program to: (1) identify the substances from the above list of categories that are applicable to the issues involving C-103, and (2) implement a phased plan which will develop the organic vapor phase characterization method and then characterize the organics and the other selected substances to the required quantitative certainty.

  15. Hydride vapor phase GaN films with reduced density of residual electrons and deep traps

    SciTech Connect (OSTI)

    Polyakov, A. Y.; Smirnov, N. B.; Govorkov, A. V.; Yugova, T. G.; Cox, H.; Helava, H.; Makarov, Yu.; Usikov, A. S.

    2014-05-14

    Electrical properties and deep electron and hole traps spectra are compared for undoped n-GaN films grown by hydride vapor phase epitaxy (HVPE) in the regular process (standard HVPE samples) and in HVPE process optimized for decreasing the concentration of residual donor impurities (improved HVPE samples). It is shown that the residual donor density can be reduced by optimization from ?10{sup 17}?cm{sup ?3} to (2–5)?×?10{sup 14}?cm{sup ?3}. The density of deep hole traps and deep electron traps decreases with decreased donor density, so that the concentration of deep hole traps in the improved samples is reduced to ?5?×?10{sup 13}?cm{sup ?3} versus 2.9?×?10{sup 16}?cm{sup ?3} in the standard samples, with a similar decrease in the electron traps concentration.

  16. Compound nuclear decay and the liquid to vapor phase transition: a physical picture

    E-Print Network [OSTI]

    Moretto, L G; Phair, L

    2005-01-01

    Analyses of multifragmentation in terms of the Fisher droplet model (FDM) and the associated construction of a nuclear phase diagram bring forth the problem of the actual existence of the nuclear vapor phase and the meaning of its associated pressure. We present here a physical picture of fragment production from excited nuclei that solves this problem and establishes the relationship between the FDM and the standard compound nucleus decay rate for rare particles emitted in first-chance decay. The compound thermal emission picture is formally equivalent to a FDM-like equilibrium description and avoids the problem of the vapor while also explaining the observation of Boltzmann-like distribution of emission times. In this picture a simple Fermi gas thermometric relation is naturally justified and verified in the fragment yields and time scales. Low energy compound nucleus fragment yields scale according to the FDM and lead to an estimate of the infinite symmetric nuclear matter critical temperature between 18 a...

  17. Liquid-vapor phase transition in nuclei or compound nucleus decay?

    E-Print Network [OSTI]

    L. G. Moretto; J. B. Elliott; L. Phair; G. J. Wozniak

    2002-09-12

    Recent analyses of multifragmentation in terms of Fisher's model and the related construction of a phase diagram brings forth the problem of the true existence of the vapor phase and the meaning of its associated pressure. Our analysis shows that a thermal emission picture is equivalent to a Fisher-like equilibrium description which avoids the problem of the vapor and explains the recently observed Boltzmann-like distribution of the emission times. In this picture a simple Fermi gas thermometric relation is naturally justified. Low energy compound nucleus emission of intermediate mass fragments is shown to scale according to Fisher's formula and can be simultaneously fit with the much higher energy ISiS multifragmentation data.

  18. Tribology Letters Vol. 10, No. 3, 2001 179 Activation of the SiC surface for vapor phase lubrication

    E-Print Network [OSTI]

    Gellman, Andrew J.

    Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA E-mail: ag4b(ad), which then decompose by -hydride elimination resulting in H2, CO, H2CO, and CH3OH desorption phase lubrication in high temperature engines. KEY WORDS: lubrication; vapor phase lubrication; SiC; Fe

  19. Scanning Kelvin probe microscopy of surface electronic structure in GaN grown by hydride vapor phase epitaxy

    E-Print Network [OSTI]

    Yu, Edward T.

    Scanning Kelvin probe microscopy of surface electronic structure in GaN grown by hydride vapor Engineering and Program in Materials Science and Engineering, University of California at San Diego, La Jolla microscopy is used to image surface potential variations in GaN 0001 grown by hydride vapor phase epitaxy

  20. Density functional theory calculations of stability and diffusion mechanisms of impurity atoms in Ge crystals

    SciTech Connect (OSTI)

    Maeta, Takahiro; Sueoka, Koji

    2014-08-21

    Ge-based substrates are being developed for applications in advanced nano-electronic devices because of their higher intrinsic carrier mobility than Si. The stability and diffusion mechanism of impurity atoms in Ge are not well known in contrast to those of Si. Systematic studies of the stable sites of 2nd to 6th row element impurity atoms in Ge crystal were undertaken with density functional theory (DFT) and compared with those in Si crystal. It was found that most of the impurity atoms in Ge were stable at substitutional sites, while transition metals in Si were stable at interstitial sites and the other impurity atoms in Si were stable at substitutional sites. Furthermore, DFT calculations were carried out to clarify the mechanism responsible for the diffusion of impurity atoms in Ge crystals. The diffusion mechanism for 3d transition metals in Ge was found to be an interstitial-substitutional diffusion mechanism, while in Si this was an interstitial diffusion mechanism. The diffusion barriers in the proposed diffusion mechanisms in Ge and Si were quantitatively verified by comparing them to the experimental values in the literature.

  1. Radiation-induced defects in GaN bulk grown by halide vapor phase epitaxy

    SciTech Connect (OSTI)

    Duc, Tran Thien; Pozina, Galia; Son, Nguyen Tien; Janzén, Erik; Hemmingsson, Carl; Ohshima, Takeshi

    2014-09-08

    Defects induced by electron irradiation in thick free-standing GaN layers grown by halide vapor phase epitaxy were studied by deep level transient spectroscopy. In as-grown materials, six electron traps, labeled D2 (E{sub C}–0.24?eV), D3 (E{sub C}–0.60?eV), D4 (E{sub C}–0.69?eV), D5 (E{sub C}–0.96?eV), D7 (E{sub C}–1.19?eV), and D8, were observed. After 2?MeV electron irradiation at a fluence of 1?×?10{sup 14?}cm{sup ?2}, three deep electron traps, labeled D1 (E{sub C}–0.12?eV), D5I (E{sub C}–0.89?eV), and D6 (E{sub C}–1.14?eV), were detected. The trap D1 has previously been reported and considered as being related to the nitrogen vacancy. From the annealing behavior and a high introduction rate, the D5I and D6 centers are suggested to be related to primary intrinsic defects.

  2. Carbon-Supported bimetallic Pd-Fe catalysts for vapor-phase hydrodeoxygenation of guaiacol

    SciTech Connect (OSTI)

    Sun, Junming; Karim, Ayman M.; Zhang, He; Kovarik, Libor; Li, Xiaohong S.; Hensley, Alyssa; McEwen, Jean-Sabin; Wang, Yong

    2013-10-01

    Abstract Carbon supported metal catalysts (Cu/C, Fe/C, Pd/C, Pt/C, PdFe/C and Ru/C) have been prepared, characterized and tested for vapor-phase hydrodeoxygenation (HDO) of guaiacol (GUA) at atmospheric pressure. Phenol was the major intermediate on all catalysts. Over the noble metal catalysts saturation of the aromatic ring was the major pathway observed at low temperature (250 °C), forming predominantly cyclohexanone and cyclohexanol. Substantial ring opening reaction was observed on Pt/C and Ru/C at higher reaction temperatures (e.g., 350 °C). Base metal catalysts, especially Fe/C, were found to exhibit high HDO activity without ring-saturation or ring-opening with the main products being benzene, phenol along with small amounts of cresol, toluene and trimethylbenzene (TMB). A substantial enhancement in HDO activity was observed on the PdFe/C catalysts. Compared with Fe/C, the yield to oxygen-free aromatic products (i.e., benzene/toluene/TMB) on PdFe/C increased by a factor of four at 350 °C, and by approximately a factor of two (83.2% versus 43.3%) at 450 °C. The enhanced activity of PdFe/C is attributed to the formation of PdFe alloy as evidenced by STEM, EDS and TPR.

  3. Compound nuclear decay and the liquid to vapor phase transition: a physical picture

    E-Print Network [OSTI]

    L. G. Moretto; J. B. Elliott; L. Phair

    2005-07-08

    Analyses of multifragmentation in terms of the Fisher droplet model (FDM) and the associated construction of a nuclear phase diagram bring forth the problem of the actual existence of the nuclear vapor phase and the meaning of its associated pressure. We present here a physical picture of fragment production from excited nuclei that solves this problem and establishes the relationship between the FDM and the standard compound nucleus decay rate for rare particles emitted in first-chance decay. The compound thermal emission picture is formally equivalent to a FDM-like equilibrium description and avoids the problem of the vapor while also explaining the observation of Boltzmann-like distribution of emission times. In this picture a simple Fermi gas thermometric relation is naturally justified and verified in the fragment yields and time scales. Low energy compound nucleus fragment yields scale according to the FDM and lead to an estimate of the infinite symmetric nuclear matter critical temperature between 18 and 27 MeV depending on the choice of the surface energy coefficient of nuclear matter.

  4. The ramifications of diffusive volume transport in classical fluid mechanics

    E-Print Network [OSTI]

    Bielenberg, James R. (James Ronald), 1976-

    2004-01-01

    The thesis that follows consists of a collection of work supporting and extending a novel reformulation of fluid mechanics, wherein the linear momentum per unit mass in a fluid continuum, m, is supposed equal to the volume ...

  5. Treatment of Produced Water Using a Surfactant Modified Zeolite/Vapor Phase Bioreactor System

    SciTech Connect (OSTI)

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

    2006-01-31

    Co-produced water from the oil and gas industry accounts for a significant waste stream in the United States. Produced waters typically contain a high total dissolved solids content, dissolved organic constituents such as benzene and toluene, an oil and grease component as well as chemicals added during the oil-production process. It has been estimated that a total of 14 billion barrels of produced water were generated in 2002 from onshore operations (Veil, 2004). Although much of this produced water is disposed via reinjection, environmental and cost considerations can make surface discharge of this water a more practical means of disposal. In addition, reinjection is not always a feasible option because of geographic, economic, or regulatory considerations. In these situations, it may be desirable, and often necessary from a regulatory viewpoint, to treat produced water before discharge. It may also be feasible to treat waters that slightly exceed regulatory limits for re-use in arid or drought-prone areas, rather than losing them to reinjection. A previous project conducted under DOE Contract DE-AC26-99BC15221 demonstrated that surfactant modified zeolite (SMZ) represents a potential treatment technology for produced water containing BTEX. Laboratory and field experiments suggest that: (1) sorption of benzene, toluene, ethylbenzene and xylenes (BTEX) to SMZ follows linear isotherms in which sorption increases with increasing solute hydrophobicity; (2) the presence of high salt concentrations substantially increases the capacity of the SMZ for BTEX; (3) competitive sorption among the BTEX compounds is negligible; and, (4) complete recovery of the SMZ sorption capacity for BTEX can be achieved by air sparging the SMZ. This report summarizes research for a follow on project to optimize the regeneration process for multiple sorption/regeneration cycles, and to develop and incorporate a vapor phase bioreactor (VPB) system for treatment of the off-gas generated during air sparging. To this end, we conducted batch and column laboratory SMZ and VPB experiments with synthetic and actual produced waters. Based on the results of the laboratory testing, a pilot scale study was designed and conducted to evaluate the combined SMZ/VPB process. An economic and regulatory feasibility analysis was also completed as part of the current study to assess the viability of the process for various water re-use options.

  6. TREATMENT OF PRODUCED WATERS USING A SURFACTANT MODIFIED ZEOLITE/VAPOR PHASE BIOREATOR SYSTEM

    SciTech Connect (OSTI)

    LYNN E. KATZ; KERRY A. KINNEY; R.S. BOWMAN; E.J. SULLIVAN

    2003-10-01

    Co-produced water from the oil and gas industry is by some estimates the largest single waste stream in the country, aside from nonhazardous industrial wastes. Characteristics of produced water include high total dissolved solids content, dissolved organic constituents such as benzene and toluene, an oil and grease component, and chemicals added during the oil-production process. While most of the produced water is disposed via reinjection, some of them must be treated to remove organic constituents before the water is discharged. An efficient, cost-effective treatment technology is needed to remove these constituents. Surfactant-modified zeolite (SMZ) has been used successfully to treat contaminated ground water for organic and inorganic constituents. In addition, the low cost of natural zeolites makes their use attractive in water-treatment applications. Our previous DOE research work (DE-AC26-99BC15221) demonstrated that SMZ could successfully remove BTEX compounds from the produced water. In addition, SMZ could be regenerated through a simple air sparging process. The primary goal of this project is to develop a robust SMZ/VPB treatment system to efficiently remove the organic constituents from produced water in a cost-effective manner. This report summarizes work of this project from March 2003 through September 2003. We have continued our investigation of SMZ regeneration from our previous DOE project. Ten saturation/stripping cycles have been completed for SMZ columns saturated with BTEX compounds. The results suggest that BTEX sorption capacity is not lost after ten saturation/regeneration cycles. The composition of produced water from a site operated by Crystal Solutions Ltd. in Wyoming has been characterized and was used to identify key semi-volatile components. Isotherms with selected semi-volatile components have been initiated and preliminary results have been obtained. The experimental vapor phase bioreactors for this project have been designed and assembled to treat the off-gas from the SMZ regeneration process. These columns will be used both in the laboratory and in the proposed field testing to be conducted next year. Innocula for the columns that degrade all of the BTEX columns have been developed.

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

    SciTech Connect (OSTI)

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

    2005-03-11

    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.

  8. ZnO/Cu(InGa)Se.sub.2 solar cells prepared by vapor phase Zn doping

    DOE Patents [OSTI]

    Ramanathan, Kannan; Hasoon, Falah S.; Asher, Sarah E.; Dolan, James; Keane, James C.

    2007-02-20

    A process for making a thin film ZnO/Cu(InGa)Se.sub.2 solar cell without depositing a buffer layer and by Zn doping from a vapor phase, comprising: depositing Cu(InGa)Se.sub.2 layer on a metal back contact deposited on a glass substrate; heating the Cu(InGa)Se.sub.2 layer on the metal back contact on the glass substrate to a temperature range between about 100.degree. C. to about 250.degree. C.; subjecting the heated layer of Cu(InGa)Se.sub.2 to an evaporant species from a Zn compound; and sputter depositing ZnO on the Zn compound evaporant species treated layer of Cu(InGa)Se.sub.2.

  9. Time-resolved photoluminescence studies of free and donor-bound exciton in GaN grown by hydride vapor phase epitaxy

    E-Print Network [OSTI]

    Time-resolved photoluminescence studies of free and donor-bound exciton in GaN grown by hydride and Electrical and Computer Engineering and Photonics Center, Boston University, Boston, Massachusetts, 02215 R in unintentionally doped GaN grown by hydride vapor phase epitaxy. Low temperature (4 K), time-integrated PL spectra

  10. Effects of carbon on phosphorus diffusion in SiGe:C and the implications on phosphorus diffusion mechanisms

    SciTech Connect (OSTI)

    Lin, Yiheng; Xia, Guangrui [Department of Materials Engineering, The University of British Columbia, 309-6350 Stores Rd, Vancouver, British Columbia V6T 1Z4 (Canada); Yasuda, Hiroshi; Wise, Rick [Texas Instruments, 13121 TI Blvd., Dallas, Texas 75243 (United States); Schiekofer, Manfred; Benna, Bernhard [Texas Instruments Deutschland GmbH, Haggertystrasse 1, 85356 Freising (Germany)

    2014-10-14

    The use of carbon (C) in SiGe base layers is an important approach to control the base layer dopant phosphorus (P) diffusion and thus enhance PNP heterojunction bipolar transistor (HBT) performance. This work quantitatively investigated the carbon impacts on P diffusion in Si?.??Ge?.??:C and Si:C under rapid thermal anneal conditions. The carbon molar fraction is up to 0.32%. The results showed that the carbon retardation effect on P diffusion is less effective for Si?.??Ge?.??:C than for Si:C. In Si?.??Ge?.??:C, there is an optimum carbon content at around 0.05% to 0.1%, beyond which more carbon incorporation does not retard P diffusion any more. This behavior is different from the P diffusion behavior in Si:C and the B in Si:C and low Ge SiGe:C, which can be explained by the decreased interstitial-mediated diffusion fraction f{sub I}{sup P,SiGe} to 95% as Ge content increases to 18%. Empirical models were established to calculate the time-averaged point defect concentrations and effective diffusivities as a function of carbon and was shown to agree with previous studies on boron, phosphorus, arsenic and antimony diffusion with carbon.

  11. The role of polymer formation during vapor phase lubrication of silicon.

    SciTech Connect (OSTI)

    Dugger, Michael Thomas; Dirk, Shawn M.; Ohlhausen, James Anthony

    2010-10-01

    The lubrication of silicon surfaces with alcohol vapors has recently been demonstrated. With a sufficient concentration of pentanol vapor present, sliding of a silica ball on an oxidized silicon wafer can proceed with no measurable wear. The initial results of time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of wear surfaces revealed a reaction product having thickness on the order of a monolayer, and with an ion spectrum that included fragments having molecular weights of 200 or more that occurred only inside the wear tracks. The parent alcohol molecule pentanol, has molecular weight of 88amu, suggesting that reactions of adsorbed alcohols on the wearing surfaces allowed polymerization of the alcohols to form higher molecular weight species. In addition to pin-on-disk studies, lubrication of silicon surfaces with pentanol vapors has also been demonstrated using MicroElectroMechanical Systems (MEMS) devices. Recent investigations of the reaction mechanisms of the alcohol molecules with the oxidized silicon surfaces have shown that wearless sliding requires a concentration of the alcohol vapor that is dependent upon the contact stress during sliding, with higher stress requiring a greater concentration of alcohol. Different vapor precursors including those with acid functionality, olefins, and methyl termination also produce polymeric reaction products, and can lubricate the silica surfaces. Doping the operating environment with oxygen was found to quench the formation of the polymeric reaction product, and demonstrates that polymer formation is not necessary for wearless sliding.

  12. Impact of thermal annealing on bulk InGaAsSbN materials grown by metalorganic vapor phase epitaxy

    SciTech Connect (OSTI)

    Kim, T. W.; Mawst, L. J.; Kim, K.; Lee, J. J.; Kuech, T. F.; Wells, N. P.; LaLumondiere, S. D.; Sin, Y.; Lotshaw, W. T.; Moss, S. C.

    2014-02-03

    Two different thermal annealing techniques (rapid thermal annealing (RTA) and in-situ post-growth annealing in the metalorganic vapor phase epitaxy (MOVPE) chamber) were employed to investigate their impact on the optical characteristics of double-heterostructures (DH) of InGaAsSbN/GaAs and on the performance of single-junction solar cell structures, all grown by MOVPE. We find that an optimized RTA procedure leads to a similar improvement in the photoluminescence (PL) intensity compared with material employing a multi-step optimized anneal within the MOVPE reactor. Time-resolved photoluminescence techniques at low temperature (LT) and room temperature (RT) were performed to characterize the carrier dynamics in bulk InGaAsSbN layers. Room temperature carrier lifetimes were found to be similar for both annealing methods, although the LT-PL (16?K) measurements of the MOVPE-annealed sample found longer lifetimes than the RTA-annealed sample (680?ps vs. 260?ps) for the PL measurement energy of 1.24?eV. InGaAsSbN-based single junction solar cells processed with the optimized RTA procedure exhibited an enhancement of the electrical performance, such as improvements in open circuit voltage, short circuit current, fill factor, and efficiency over solar cells subjected to the in-situ MOVPE annealing technique.

  13. Journal of Light Emitting Diodes Vol 2 N0 1, April 2010 1 Abstract--In metal organic vapor phase epitaxy we developed

    E-Print Network [OSTI]

    Wetzel, Christian M.

    Journal of Light Emitting Diodes Vol 2 N0 1, April 2010 1 Abstract-- In metal organic vapor phase epitaxy we developed GaInN/GaN quantum well material suitable for 500 ­ 580 nm light emitting diodes at longer wavelengths. Index Terms-- a-plane GaN, GaInN, Green light emitting diode, m-plane GaN I

  14. Li Ion Diffusion Mechanisms in the Crystalline Electrolyte Yaojun A. Du and N. A. W. Holzwarth*,z

    E-Print Network [OSTI]

    Holzwarth, Natalie

    electronically September 6, 2007. Recently, there has been a lot of interest in solid electrolyte ma- terialsLi Ion Diffusion Mechanisms in the Crystalline Electrolyte -Li3PO4 Yaojun A. Du and N. A. W. Holzwarth*,z Department of Physics, Wake-Forest University, Winston-Salem, North Carolina 27109, USA Solid

  15. Turbulent mixing, viscosity, diffusion and gravity in the formation of cosmological structures: the fluid mechanics of dark matter

    E-Print Network [OSTI]

    Carl H. Gibson

    2000-12-18

    Self-gravitational structure formation theory for astrophysics and cosmology is revised using nonlinear fluid mechanics. Gibson's 1996-2000 theory balances fluid mechanical forces with gravitational forces and density diffusion with gravitational diffusion at critical viscous, turbulent, magnetic, and diffusion length scales termed Schwarz scales. Instability occurs for scales larger than the largest Schwarz scale rather than only for scales larger than the acoustic scale introduced by Jeans 1902. From the new theory, the inner-halo-dark-matter of galaxies consists of dark proto-globular-star-cluster (PGC) clumps of small-planetary-mass objects called primordial fog particles (PFPs) formed soon after decoupling at 300,000 years. PFPs explain Schild's 1996 "rogue planets >... likely to be the missing mass" of a quasar lens-galaxy. WIMP dark matter fluid is super-diffusive and fragments at large L_SD scales to form outer-galaxy-halos. In the beginning of structure formation 30,000 years after the Big Bang the viscous Schwarz scale L_SV matched the horizon scale L_H at proto-galaxy-supercluster masses, decreasing to proto-galaxy fragments at 300,000 years. WIMP diffusivities from observed outer-halo (L_SD) scales indicate WIMP particle masses in the neutrino rather than neutralino range.

  16. Microscopic Mechanism of Water Diffusion in Glucose Glasses Valeria Molinero and William A. Goddard III

    E-Print Network [OSTI]

    Goddard III, William A.

    that vitrification is not suffi- cient to arrest water mobility: water can still diffuse in the glassy carbohydrate by the computational cost of atomistic simulations. We study here the relaxation of a 12.2% water-glucose (WG) glass

  17. Turbulent mixing, diffusion and gravity in the formation of cosmological structures: the fluid mechanics of dark matter

    E-Print Network [OSTI]

    Carl H. Gibson

    1999-04-18

    The theory of gravitational structure formation in astrophysics and cosmology is revised based on real fluid behavior and turbulent mixing theory. Gibson's 1996-1998 theory balances fluid mechanical forces with gravitational forces and density diffusivity with gravitational diffusivity at critical viscous, turbulent, magnetic, and diffusion length scales termed Schwarz scales L_SX. Condensation and void formation occurs on non-acoustic density nuclei produced by turbulent mixing for scales L>=L_SXmax rather than on sound wave crests and troughs for L>=L_J as required by Jeans's 1902 linear acoustic theory. Schwarz scales L_SX = L_SV, L_ST, L_SM, or L_SD may be smaller or larger than Jeans's scale L_J. Thus, a very different "nonlinear" cosmology emerges to replace the currently accepted "linear" cosmology. According to the new theory, most of the inner halo dark matter of galaxies consists of planetary mass objects that formed soon after the plasma to neutral gas transition 300,000 years after the Big Bang. These objects are termed primordial fog particles (PFPs) and provide an explanation for Schild's 1996 "rogue planets ... likely to be the missing mass" of his observed quasar-lens galaxy, inferred from the twinkling frequencies of both quasar images and their phased difference.

  18. A thermo-mechanically-coupled theory accounting for hydrogen diffusion and large elastic–viscoplastic deformations of metals

    E-Print Network [OSTI]

    Anand, Lallit

    In this paper we develop a thermodynamically-consistent coupled-theory which accounts for diffusion of hydrogen, diffusion of heat, and large elastic–viscoplastic deformations of metals. The theory should be of utility in ...

  19. An investigation on microstructure evolution and mechanical properties during liquid state diffusion bonding of Al2024 to Ti–6Al–4V

    SciTech Connect (OSTI)

    Samavatian, Majid; Halvaee, Ayoub; Amadeh, Ahmad Ali; Khodabandeh, Alireza

    2014-12-15

    Joining mechanism of Ti/Al dissimilar alloys was studied during liquid state diffusion bonding process using Cu/Sn/Cu interlayer at 510 °C under vacuum of 7.5 × 10{sup ?5} Torr for various bonding times. The microstructure and compositional changes in the joint zone were analyzed by scanning electron microscopy equipped with energy dispersive spectroscopy and X-ray diffraction. Microhardness and shear strength tests were also applied to study the mechanical properties of the joints. It was found that with an increase in bonding time, the elements of interlayer diffused into the parent metals and formed various intermetallic compounds at the interface. Diffusion process led to the isothermal solidification and the bonding evolution in the joint zone. The results from mechanical tests showed that microhardness and shear strength values have a straight relation with bonding time so that the maximum shear strength of joint was obtained for a bond made with 60 min bonding time. - Highlights: • Liquid state diffusion bonding of Al2024 to Ti–6Al–4V was performed successfully. • Diffusion of the elements caused the formation of various intermetallics at the interface. • Microhardness and shear strength values have a straight relation with bonding time. • The maximum shear strength reached to 36 MPa in 60 min bonding time.

  20. A combined kick-out and dissociative diffusion mechanism of grown-in Be in InGaAs and InGaAsP. A new finite difference-Bairstow method for solution of the diffusion equations

    SciTech Connect (OSTI)

    Koumetz, Serge D., E-mail: Serge.Koumetz@univ-rouen.fr; Martin, Patrick; Murray, Hugues [Normandie Université-Université de Rouen-ENSICAEN-UMR 6508 LaMIPS, Laboratoire commun CNRS-NXP-PRESTO-ENSICAEN-UCBN 2, rue de la Girafe BP 5120, F-14079 Caen (France)

    2014-09-14

    Experimental results on the diffusion of grown-in beryllium (Be) in indium gallium arsenide (In{sub 0.53}Ga{sub 0.47}As) and indium gallium arsenide phosphide (In{sub 0.73}Ga{sub 0.27}As{sub 0.58}P{sub 0.42}) gas source molecular beam epitaxy alloys lattice-matched to indium phosphide (InP) can be successfully explained in terms of a combined kick-out and dissociative diffusion mechanism, involving neutral Be interstitials (Be{sub i}{sup 0}), singly positively charged gallium (Ga), indium (In) self-interstitials (I{sub III}{sup +}) and singly positively charged Ga, In vacancies (V{sub III}{sup +}). A new numerical method of solution to the system of diffusion equations, based on the finite difference approximations and Bairstow's method, is proposed.

  1. The use of DRIFTS-MS and kinetic studies to determine the role of acetic acid in the palladium-catalyzed vapor-phase synthesis of vinyl acetate

    SciTech Connect (OSTI)

    Augustine, S.M.; Blitz, J.P. (Quantum Chemical Corp., Cincinnati, OH (United States))

    1993-07-01

    Supported palladium catalyzes the synthesis of vinyl acetate (VA) by oxyacetylation of ethylene. Alkali promoters increase activity and selectivity. The role of acetic acid (HOAc) in these processes is not well understood. Activation energy studies show that HOAc alters the catalyst site and lowers the reaction barrier to VA formation. After correction for this effect, the kinetics reveal that as a reagent HOAc is zero order. This is probably due to a strong adsorption of HOAc and Pd which forms the catalyst active phase. Detailed spectroscopic studies support this conclusion. The surface processes on a supported vinyl acetate catalyst were studied using a method which couples diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) with mass spectrometry (MS). The DRIFTS-MS technique combines the capability of selectively analyzing IR-active surface species with sensitive detection of transient reaction products. By comparing the catalyst with mixtures of palladium acetate powder physically dispersed in potassium chloride, it is determined that the active phase on the catalyst is a form of palladium acetate. Compound formation is consistent with the strong chemisorption of HOAc on Pd. Kinetic analysis of temperature-programmed reaction(TPRxn) data suggests that Pd metal or metal oxide adjacent to the active site is important in the reaction mechanism. 25 refs., 10 figs., 2 tabs.

  2. Authorized Limit Evaluation of Spent Granular Activated Carbon Used for Vapor-Phase Remediation at the Lawrence Livermore National Laboratory Livermore, California

    SciTech Connect (OSTI)

    Devany, R; Utterback, T

    2007-01-11

    This report provides a technical basis for establishing radiological release limits for granular activated carbon (GAC) containing very low quantities of tritium and radon daughter products generated during environmental remediation activities at Lawrence Livermore National Laboratory (LLNL). This evaluation was conducted according to the Authorized Limit procedures specified in United States Department of Energy (DOE) Order 5400.5, Radiation Protection of the Public and the Environment (DOE, 1993) and related DOE guidance documents. The GAC waste is currently being managed by LLNL as a Resource Conservation and Recovery Act (RCRA) mixed waste. Significant cost savings can be achieved by developing an Authorized Limit under DOE Order 5400.5 since it would allow the waste to be safely disposed as a hazardous waste at a permitted off-site RCRA treatment and disposal facility. LLNL generates GAC waste during vapor-phase soil remediation in the Trailer 5475 area. While trichloroethylene and other volatile organic compounds (VOCs) are the primary targets of the remedial action, a limited amount of tritium and radon daughter products are contained in the GAC at the time of disposal. As defined in DOE Order 5400.5, an Authorized Limit is a level of residual radioactive material that will result in an annual public dose of 100 milliroentgen-equivalent man per year (mrem/year) or less. In 1995, DOE issued additional release requirements for material sent to a landfill that is not an authorized low-level radioactive waste disposal facility. Per guidance, the disposal site will be selected based on a risk/benefit assessment under the As-Low-As-Reasonably-Achievable (ALARA) process while ensuring that individual doses to the public are less than 25 mrem in a year, ground water is protected, the release would not necessitate further remedial action for the disposal site, and the release is coordinated with all appropriate authorities. The 1995 release requirements also state that Authorized Limits may be approved by DOE field office managers without DOE headquarters (EH-1) approval if a reasonably conservative dose assessment demonstrates that: (1) Public doses will not exceed one mrem per year individually or 10 person-rem/year collectively; (2) Appropriate record keeping and data collection procedures are in place; (3) Copies of the release evaluation and procedures are properly maintained; and (4) Coordination with all applicable state and federal agencies is documented. Based on the above guidelines, this report uses one mrem/year for individual members of the public and 10 person-rem/year for the collective population as upper-bound doses for the determination of Authorized Limits.

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

    SciTech Connect (OSTI)

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

    2007-12-31

    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.

  4. 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)

    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)

    2013-08-19

    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.

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

    E-Print Network [OSTI]

    Goddard III, William A.

    Proton diffusion pathways and rates in Y-doped BaZrO3 solid oxide electrolyte from quantum in the BYZ electrolyte. Indeed, the calculated values bracket the experimental value of Ea=0.44 eV. Based been proposed for the BYZ electrolyte. The thermal librations of BO6 octahedra and uncorrelated thermal

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

    E-Print Network [OSTI]

    Ortiz, Michael

    ) Department of Mechanical and Aerospace Engineering and Program in Applied and Computational Mathematics, and mechanical engineering. The deleterious effect of hydrogen on the mechanical properties of metals and alloys as the two most viable for stable phases. Material degradation via the formation of brittle hydride phases,9

  7. Growth mechanism of catalyst-and template-free group III-nitride nanorods Yong Sun Won a,b,,1

    E-Print Network [OSTI]

    Anderson, Timothy J.

    , Young Seok Kim a , Olga Kryliouk a,c,2,Ã, Timothy J. Anderson a a Department of Chemical Engineering calculation A1. Phase equilibria A3. Hydride vapor phase epitaxy B2. Semiconducting III­V materials a b s t r a c t A feasible mechanism for catalyst- and template-free group III-nitride nanorod growth by hydride

  8. Liquid-phase compositions from vapor-phase analyses: 4, Preliminary comparisons of calculations with experimental data on N/sub 2/, O/sub 2/, F/sub 2/, SiF/sub 4/, and ClF/sub 3/ in UF/sub 6/

    SciTech Connect (OSTI)

    Davis, W. Jr.

    1987-11-01

    Currently, liquid-phase samples from uranium hexafluoride (UF/sub 6/) cylinders are used at all US DOE /sup 235/U enrichment facilities to determine the chemical content of cylinders - a requisite in the control and accountability of nuclear materials. Previously published reports note the economic incentives to use vapor-phase sampling for volatile impurities (as a partial replacement for liquid-phase sampling) if the liquid-phase composition can be determined from analysis of vapor-phase samples by using a model of vapor-liquid equilibrium between UF/sub 6/ and its common impurities. Such a model was adapted for this purpose in earlier work. Hydrogen fluoride, a common impurity, in UF/sub 6/ was shown not to conform to the model although other methods for calculating its concentration in the liquid phase from vapor-phase analyses were presented. This report describes preliminary comparisons with experimental data of model calculations of concentrations of nitrogen, oxygen, fluorine, chlorine trifluoride, and silicon tetrafluoride in liquid UF/sub 6/ based on analyses of the vapor phases. 4 figs., 13 tabs.

  9. Potential-induced degradation in solar cells: Electronic structure and diffusion mechanism of sodium in stacking faults of silicon

    SciTech Connect (OSTI)

    Ziebarth, Benedikt Gumbsch, Peter; Mrovec, Matous; Elsässer, Christian

    2014-09-07

    Sodium decorated stacking faults (SFs) were recently identified as the primary cause of potential-induced degradation in silicon (Si) solar-cells due to local electrical short-circuiting of the p-n junctions. In the present study, we investigate these defects by first principles calculations based on density functional theory in order to elucidate their structural, thermodynamic, and electronic properties. Our calculations show that the presence of sodium (Na) atoms leads to a substantial elongation of the Si-Si bonds across the SF, and the coverage and continuity of the Na layer strongly affect the diffusion behavior of Na within the SF. An analysis of the electronic structure reveals that the presence of Na in the SF gives rise to partially occupied defect levels within the Si band gap that participate in electrical conduction along the SF.

  10. Electromagnetic Nature of Thermo-Mechanical Mass-Energy Transfer Due to Photon Diffusive Re-Emission and Propagation

    E-Print Network [OSTI]

    Kostic, Milivoje M.

    (parabolic differential equation), allowing infinite speed of thermal energy propagation (i.e., a change mass-energy equivalence with `thermon' quasi-particle leading to inertia of heat transfer. Thermal research and applications, related to the conclusions deduced and open questions posed. www.kostic.niu.edu/Nature_of_Thermal_and_Mechanical_Energy

  11. Cosmology with matter diffusion

    SciTech Connect (OSTI)

    Calogero, Simone; Velten, Hermano E-mail: velten@cce.ufes.br

    2013-11-01

    We construct a viable cosmological model based on velocity diffusion of matter particles. In order to ensure the conservation of the total energy-momentum tensor in the presence of diffusion, we include a cosmological scalar field ? which we identify with the dark energy component of the universe. The model is characterized by only one new degree of freedom, the diffusion parameter ?. The standard ?CDM model can be recovered by setting ? = 0. If diffusion takes place (? > 0) the dynamics of the matter and of the dark energy fields are coupled. We argue that the existence of a diffusion mechanism in the universe may serve as a theoretical motivation for interacting models. We constrain the background dynamics of the diffusion model with Supernovae, H(z) and BAO data. We also perform a perturbative analysis of this model in order to understand structure formation in the universe. We calculate the impact of diffusion both on the CMB spectrum, with particular attention to the integrated Sachs-Wolfe signal, and on the matter power spectrum P(k). The latter analysis places strong constraints on the magnitude of the diffusion mechanism but does not rule out the model.

  12. Hierarchical diffusion

    SciTech Connect (OSTI)

    Bachas, C.P.

    1988-02-01

    We review the solution and properties of the diffusion equation in a hierarchical or ultrametric space. 11 refs.

  13. Modeling CO[subscript 2] Chemical Effects on CO Formation in Oxy-Fuel Diffusion Flames Using Detailed, Quasi-Global, and Global Reaction Mechanisms

    E-Print Network [OSTI]

    Chen, Lei

    Interest in oxy-fuel combustion as one of the leading carbon capture technologies has grown significantly in the past two decades. Experimental studies have shown higher CO concentration in oxy-fuel diffusion flames than ...

  14. Diffusion in silicon isotope heterostructures

    SciTech Connect (OSTI)

    Silvestri, Hughes Howland

    2004-05-14

    The simultaneous diffusion of Si and the dopants B, P, and As has been studied by the use of a multilayer structure of isotopically enriched Si. This structure, consisting of 5 pairs of 120 nm thick natural Si and {sup 28}Si enriched layers, enables the observation of {sup 30}Si self-diffusion from the natural layers into the {sup 28}Si enriched layers, as well as dopant diffusion from an implanted source in an amorphous Si cap layer, via Secondary Ion Mass Spectrometry (SIMS). The dopant diffusion created regions of the multilayer structure that were extrinsic at the diffusion temperatures. In these regions, the Fermi level shift due to the extrinsic condition altered the concentration and charge state of the native defects involved in the diffusion process, which affected the dopant and self-diffusion. The simultaneously recorded diffusion profiles enabled the modeling of the coupled dopant and self-diffusion. From the modeling of the simultaneous diffusion, the dopant diffusion mechanisms, the native defect charge states, and the self- and dopant diffusion coefficients can be determined. This information is necessary to enhance the physical modeling of dopant diffusion in Si. It is of particular interest to the modeling of future electronic Si devices, where the nanometer-scale features have created the need for precise physical models of atomic diffusion in Si. The modeling of the experimental profiles of simultaneous diffusion of B and Si under p-type extrinsic conditions revealed that both species are mediated by neutral and singly, positively charged Si self-interstitials. The diffusion of As and Si under extrinsic n-type conditions yielded a model consisting of the interstitialcy and vacancy mechanisms of diffusion via singly negatively charged self-interstitials and neutral vacancies. The simultaneous diffusion of P and Si has been modeled on the basis of neutral and singly negatively charged self-interstitials and neutral and singly positively charged P species. Additionally, the temperature dependence of the diffusion coefficient of Si in Ge was measured over the temperature range of 550 C to 900 C using a buried Si layer in an epitaxially grown Ge layer.

  15. Dynamics of multiphoton excitation and quantum diffusion in Rydberg atoms

    E-Print Network [OSTI]

    Chu, Shih-I; Wang, Kwanghsi

    1989-02-15

    with a different excitation mechanism. In this paper, we emphasize the study of the two major excitation mechanisms: quantum diffusion and multiphoton resonant excitation. The region dominated by quantum diffusion lies in the frequency range ?c

  16. Study of minority carrier diffusion lengths in photoactive layers of multijunction solar cells

    SciTech Connect (OSTI)

    Mintairov, S. A. Andreev, V. M.; Emelyanov, V. M.; Kalyuzhnyy, N. A.; Timoshina, N. K.; Shvarts, M. Z.; Lantratov, V. M.

    2010-08-15

    A technique for determining a minority carrier's diffusion length in photoactive III-V layers of solar cells by approximating their spectral characteristics is presented. Single-junction GaAs, Ge and multi-junction GaAs/Ge, GaInP/GaAs, and GaInP/GaInAs/Ge solar cells fabricated by hydride metal-organic vapor-phase epitaxy (H-MOVPE) have been studied. The dependences of the minority carrier diffusion length on the doping level of p-Ge and n-GaAs are determined. It is shown that the parameters of solid-state diffusion of phosphorus atoms to the p-Ge substrate from the n-GaInP nucleation layer are independent of the thickness of the latter within 35-300 nm. It is found that the diffusion length of subcells of multijunction structures in Ga(In)As layers is smaller in comparison with that of single-junction structures.

  17. EK424 THERMODYNAMICS AND STATISTICAL MECHANICS (Spring 2015) Thermodynamics is the study of processes (e.g., expansion of a gas, boiling of water, or diffusion

    E-Print Network [OSTI]

    Vajda, Sandor

    EK424 THERMODYNAMICS AND STATISTICAL MECHANICS (Spring 2015) 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

  18. Moisture Diffusion in Asphalt Binders and Fine Aggregate Mixtures 

    E-Print Network [OSTI]

    Vasconcelos, Kamilla L.

    2011-08-08

    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...

  19. Parallel flow diffusion battery

    DOE Patents [OSTI]

    Yeh, H.C.; Cheng, Y.S.

    1984-01-01

    A parallel flow diffusion battery for determining the mass distribution of an aerosol has a plurality of diffusion cells mounted in parallel to an aerosol stream, each diffusion cell including a stack of mesh wire screens of different density.

  20. Parallel flow diffusion battery

    DOE Patents [OSTI]

    Yeh, Hsu-Chi (Albuquerque, NM); Cheng, Yung-Sung (Albuquerque, NM)

    1984-08-07

    A parallel flow diffusion battery for determining the mass distribution of an aerosol has a plurality of diffusion cells mounted in parallel to an aerosol stream, each diffusion cell including a stack of mesh wire screens of different density.

  1. Microfabricated diffusion source

    DOE Patents [OSTI]

    Oborny, Michael C. (Albuquerque, NM); Frye-Mason, Gregory C. (Cedar Crest, NM); Manginell, Ronald P. (Albuquerque, NM)

    2008-07-15

    A microfabricated diffusion source to provide for a controlled diffusion rate of a vapor comprises a porous reservoir formed in a substrate that can be filled with a liquid, a headspace cavity for evaporation of the vapor therein, a diffusion channel to provide a controlled diffusion of the vapor, and an outlet to release the vapor into a gas stream. The microfabricated diffusion source can provide a calibration standard for a microanalytical system. The microanalytical system with an integral diffusion source can be fabricated with microelectromechanical systems technologies.

  2. Facilitated diffusion of proteins on chromatin

    E-Print Network [OSTI]

    O. Benichou; C. Chevalier; B. Meyer; R. Voituriez

    2011-01-26

    We present a theoretical model of facilitated diffusion of proteins in the cell nucleus. This model, which takes into account the successive binding/unbinding events of proteins to DNA, relies on a fractal description of the chromatin which has been recently evidenced experimentally. Facilitated diffusion is shown quantitatively to be favorable for a fast localization of a target locus by a transcription factor, and even to enable the minimization of the search time by tuning the affinity of the transcription factor with DNA. This study shows the robustness of the facilitated diffusion mechanism, invoked so far only for linear conformations of DNA.

  3. Surveying Diffusion in Complex Geometries. An Essay

    E-Print Network [OSTI]

    Denis Grebenkov

    2009-09-08

    The surrounding world surprises us by the beauty and variety of complex shapes that emerge from nanometric to macroscopic scales. Natural or manufactured materials (sandstones, sedimentary rocks and cement), colloidal solutions (proteins and DNA), biological cells, tissues and organs (lungs, kidneys and placenta), they all present irregularly shaped "scenes" for a fundamental transport "performance", that is, diffusion. Here, the geometrical complexity, entangled with the stochastic character of diffusive motion, results in numerous fascinating and sometimes unexpected effects like diffusion screening or localization. These effects control many diffusion-mediated processes that play an important role in heterogeneous catalysis, biochemical mechanisms, electrochemistry, growth phenomena, oil recovery, or building industry. In spite of a long and rich history of academic and industrial research in this field, it is striking to see how little we know about diffusion in complex geometries, especially the one which occurs in three dimensions. We present our recent results on restricted diffusion. We look into the role of geometrical complexity at different levels, from boundary microroughness to hierarchical structure and connectivity of the whole diffusion-confining domain. We develop a new approach which consists in combining fast random walk algorithms with spectral tools. The main focus is on studying diffusion in model complex geometries (von Koch boundaries, Kitaoka acinus, etc.), as well as on developing and testing spectral methods. We aim at extending this knowledge and at applying the accomplished arsenal of theoretical and numerical tools to structures found in nature and industry.

  4. Organic lateral heterojunction devices for vapor-phase chemical detection

    E-Print Network [OSTI]

    Ho, John C., 1980-

    2009-01-01

    As the U.S. is engaged in battle overseas, there is an urgent need for the development of sensors for early warning and protection of military forces against potential attacks. On the battlefields, improvised explosive ...

  5. MODELLING AND SIMULATION OF LIQUID-VAPOR PHASE TRANSITION

    E-Print Network [OSTI]

    Faccanoni, Gloria

    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 Generator Turbine Generator Cooling Tower Condenser Cooling Water Pump Reactor Core Reactor Vessel Control

  6. Propane-induced biodegradation of vapor phase trichloroethylene...

    Office of Scientific and Technical Information (OSTI)

    Resource Type: Journal Article Resource Relation: Journal Name: Biotechnology and Bioengineering; Journal Volume: 46; Journal Issue: 4; Other Information: PBD: 20 May 1995 Country...

  7. Mechanistic aspects of vapor phase lubrication of silicon. (Conference) |

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(JournalspectroscopyReport) | SciTechelement methodby hybrid-compoundSciTech Connect

  8. Propane-induced biodegradation of vapor phase trichloroethylene (Journal

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeeding accessusers'(x≤2)Article)SciTechon MPAS LandArticle) | SciTech

  9. Analytical solutions to matrix diffusion problems

    SciTech Connect (OSTI)

    Kekäläinen, Pekka

    2014-10-06

    We report an analytical method to solve in a few cases of practical interest the equations which have traditionally been proposed for the matrix diffusion problem. In matrix diffusion, elements dissolved in ground water can penetrate the porous rock surronuding the advective flow paths. In the context of radioactive waste repositories this phenomenon provides a mechanism by which the area of rock surface in contact with advecting elements is greatly enhanced, and can thus be an important delay mechanism. The cases solved are relevant for laboratory as well for in situ experiments. Solutions are given as integral representations well suited for easy numerical solution.

  10. Diffusion of n-type dopants in germanium

    SciTech Connect (OSTI)

    Chroneos, A.; Bracht, H.

    2014-03-15

    Germanium is being actively considered by the semiconductor community as a mainstream material for nanoelectronic applications. Germanium has advantageous materials properties; however, its dopant-defect interactions are less understood as compared to the mainstream material, silicon. The understanding of self- and dopant diffusion is essential to form well defined doped regions. Although p-type dopants such as boron exhibit limited diffusion, n-type dopants such as phosphorous, arsenic, and antimony diffuse quickly via vacancy-mediated diffusion mechanisms. In the present review, we mainly focus on the impact of intrinsic defects on the diffusion mechanisms of donor atoms and point defect engineering strategies to restrain donor atom diffusion and to enhance their electrical activation.

  11. Acoustic Enhancement of Surface Diffusion Chengping Wu,

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    provides an attractive alternative to thermal activation in thin film growth on heat-sensitive substrates to the thermal activation in thin film growth on heat-sensitive substrates. 2. MECHANISMS OF ACOUSTIC ACTIVATION, Russia *S Supporting Information ABSTRACT: The idea of acoustic activation of surface diffusion

  12. VOLUME 76, NUMBER 26 P H Y S I C A L R E V I E W L E T T E R S 24 JUNE 1996 Dimer Shearing as a Novel Mechanism for Cluster Diffusion and Dissociation

    E-Print Network [OSTI]

    . This process provides the easiest pathway for diffusion of compact clusters of sizes 4, 6, and 8 of cluster dif- fusion and dissociation in metal (100) epitaxy have been based on the central assumption of a col- lective atomic process, shear motion of a dimer belonging to a compact cluster. This previously

  13. Fast Explicit Operator Splitting Method for Convection-Diffusion Equations

    E-Print Network [OSTI]

    Kurganov, Alexander

    to the one- and two-dimensional systems of convection-diffusion equations which model the polymer flooding) processes in fluid mechanics, astrophysics, me- teorology, multiphase flow in oil reservoirs, polymer flow

  14. FLAMMABLE GAS DIFFUSION THROUGH SINGLE SHELL TANK (SST) DOMES

    SciTech Connect (OSTI)

    MEACHAM, J.E.

    2003-11-10

    This report quantified potential hydrogen diffusion through Hanford Site Single-Shell tank (SST) domes if the SSTs were hypothetically sealed airtight. Results showed that diffusion would keep headspace flammable gas concentrations below the lower flammability limit in the 241-AX and 241-SX SST. The purpose of this document is to quantify the amount of hydrogen that could diffuse through the domes of the SSTs if they were hypothetically sealed airtight. Diffusion is assumed to be the only mechanism available to reduce flammable gas concentrations. The scope of this report is limited to the 149 SSTs.

  15. Diffusion between evolving interfaces

    E-Print Network [OSTI]

    Janne Juntunen; Juha Merikoski

    2010-11-19

    Diffusion in an evolving environment is studied by continuos-time Monte Carlo simulations. Diffusion is modelled by continuos-time random walkers on a lattice, in a dynamic environment provided by bubbles between two one-dimensional interfaces driven symmetrically towards each other. For one-dimensional random walkers constrained by the interfaces, the bubble size distribution domi- nates diffusion. For two-dimensional random walkers, it is also controlled by the topography and dynamics of the interfaces. The results of the one-dimensional case are recovered in the limit where the interfaces are strongly driven. Even with simple hard-core repulsion between the interfaces and the particles, diffusion is found to depend strongly on the details of the dynamical rules of particles close to the interfaces. Article reference: Journal of Physics: Condensed Matter 22, 465402 (2010).

  16. Journal Diffusion Factors a measure of diffusion? Tove Faber Frandsen

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Journal Diffusion Factors ­ a measure of diffusion? Tove Faber Frandsen Royal School of Library In this paper we show that the measure of diffusion introduced by Ian Rowlands called the Journal Diffusion Factor (JDF) is highly negatively correlated with the number of citations, leading highly cited journals

  17. LOHD: Location-Oblivious Hybrid data Diffusion in wireless sensor Xu Cheng, Feng Wang, Jiangchuan Liu *

    E-Print Network [OSTI]

    Liu, Jiangchuan (JC)

    networks Data diffusion Broadcast Hybrid PUSH PULL Location information a b s t r a c t Data-centric design information to interested nodes and thus demand efficient diffusion mechanisms. In such applications, a data-centric. A pioneer work on data-centric routing is direct diffusion [2], which suggests a two-phase pull algorithm

  18. Diffusion of tungsten clusters on tungsten (110) surface

    SciTech Connect (OSTI)

    Chen, Dong; Hu, Wangyu; Yang, Jianyu; Deng, Huiqiu; Sun, Lixian; Gao, Fei

    2009-04-01

    Using molecular dynamics simulation and modified analytic embedded-atom method, we have investigated the self-diffusion of clusters on a tungsten (110) surface. As compared to the linear-chain configuration, the close-packed islands for tungsten clusters containing more than nine adatoms have been predicted to be more stable with the relatively lower binding energies. The migration energies show an interesting and oscillating behavior with increasing cluster size. The tetramer, hexamer and octamer have obviously higher migration energies than the others. The different atomic configurations and diffusion mechanisms have been determined during the diffusion processes. It is clear that the dimer-shearing mechanism occurs inside the hexamer, while it occurs at the periphery of heptamer. The successive hopping mechanism of individual atom is of critical importance in the migration of the clusters containing five or fewer adatoms. In addition, the diffusion of a cluster with nine adatoms is achieved through the changes of the cluster shape.

  19. Bottom Drag, eddy diffusivity, wind work and the power integrals

    E-Print Network [OSTI]

    Young, William R.

    Bottom Drag, eddy diffusivity, wind work and the power integrals Bill Young, Andrew Thompson field i.e., the meridional heat flux is pro Moreover, the mechanical energy balance in a statistical Moreover, the mechanical energy balance in a statistically st Appendix A) is U-2 x = | - 2 |2 + hyp

  20. Mechanical and Aerospace Engineering

    E-Print Network [OSTI]

    and lithium ion batteries. Our interest is to understand how solid diffusion generates mechanical stresses in lithium batteries. Using input from ab initio and molecular dynamic simulations, we investigated to the presence of ionic fluxes. The second example is on the insertion of lithium into silicon in silicon anodes

  1. Partially Reflected Diffusion

    E-Print Network [OSTI]

    A. Singer; Z. Schuss; D. Holcman

    2007-09-02

    The radiation (reaction, Robin) boundary condition for the continuum diffusion equation is widely used in chemical and biological applications to express reactive boundaries. The underlying trajectories of the diffusing particles are believed to be partially absorbed and partially reflected at the reactive boundary, however, the relation between the reaction (radiation) constant in the Robin boundary condition and the reflection probability is still unclear. In this paper we clarify the issue by finding the relation between the reaction (radiation) constant and the absorption probability of the diffusing trajectories at the boundary. We analyze the Euler scheme for the underlying It\\^o dynamics, which is assumed to have variable drift and diffusion tensor, with partial reflection at the boundary. Trajectories that cross the boundary are terminated with a given probability and otherwise are reflected in a normal or oblique direction. We use boundary layer analysis of the corresponding Wiener path integral to resolve the non-uniform convergence of the probability density function of the numerical scheme to the solution of the Fokker-Planck equation with the Robin boundary condition, as the time step is decreased. We show that the Robin boundary condition is recovered in the limit iff trajectories are reflected in the co-normal direction. We find the relation of the reactive constant to the termination probability. We show the effect of using the new relation in numerical simulations.

  2. Structure of Laminar Sooting Inverse Diffusion Flames

    E-Print Network [OSTI]

    Mikofski, Mark A

    2007-01-01

    Combust. Structure of Laminar Sooting Inverse Diffusion2002, p. 252. Structure of Laminar Sooting Inverse Diffusion219-226. Structure of Laminar Sooting Inverse Diffusion

  3. Sandia Energy - Diffusion Bonding Characterization

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

    bond surface is poor or only the region near this corner. Diffusion 7-8-9 "Diffusion Welding and Brazing," in Welding Handbook, 7th ed., American Welding Society, 1980, p 311-335...

  4. Diffusion on (110) Surface of Molecular Crystal Pentaerythritol Tetranitrate

    SciTech Connect (OSTI)

    Wang, J; Golfinopoulos, T; Gee, R H; Huang, H

    2007-01-25

    Using classical molecular dynamics simulations, we investigate the diffusion mechanisms of admolecules on the (110) surface of molecular crystal pentaerythritol tetranitrate. Our results show that (1) admolecules are stable at off lattice sites, (2) admolecules diffuse along close-packed [1{bar 1}1] and [{bar 1}11] directions, and (3) admolecules detach from the surface at 350K and above. Based on the number of diffusion jumps as a function of temperature, we estimate the jump frequency to be v=1.14 x 10{sup 12} e{sup -0.08eV/kT} per second.

  5. Peridynamic thermal diffusion

    SciTech Connect (OSTI)

    Oterkus, Selda [Department of Aerospace and Mechanical Engineering, The University of Arizona, Tucson, AZ 85721 (United States); Madenci, Erdogan, E-mail: madenci@email.arizona.edu [Department of Aerospace and Mechanical Engineering, The University of Arizona, Tucson, AZ 85721 (United States); Agwai, Abigail [Intel Corporation, Chandler, AZ 85226 (United States)

    2014-05-15

    This study presents the derivation of ordinary state-based peridynamic heat conduction equation based on the Lagrangian formalism. The peridynamic heat conduction parameters are related to those of the classical theory. An explicit time stepping scheme is adopted for numerical solution of various benchmark problems with known solutions. It paves the way for applying the peridynamic theory to other physical fields such as neutronic diffusion and electrical potential distribution.

  6. Multiple regimes of diffusion

    E-Print Network [OSTI]

    B. Mehlig; M. Wilkinson; V. Bezuglyy; K. Gustavsson; K. Nakamura

    2009-01-20

    We consider the diffusion of independent particles experiencing random accelerations by a space- and time-dependent force as well as viscous damping. This model can exhibit several asymptotic behaviours, depending upon the limiting cases which are considered, some of which have been discussed in earlier work. Here we explore the full space of dimensionless parameters, and introduce an "asymptotic phase diagram" which delineates the limiting regimes.

  7. Diffusive Acceleration of Ions at Interplanetary Shocks

    E-Print Network [OSTI]

    Matthew G. Baring; Errol J. Summerlin

    2005-06-08

    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.

  8. Correspondences between Wavelet Shrinkage and Nonlinear Diffusion

    E-Print Network [OSTI]

    variants [8,31], total variation (TV) diffusion [2], or balanced forward-backward (BFB) diffusion [21

  9. State protection under collective damping and diffusion

    SciTech Connect (OSTI)

    Ponte, M. A. de [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Caixa Postal 369, 13560-590 Sao Carlos, SP (Brazil); Departamento de Fisica, Universidade Regional do Cariri, 63010-970 Juazeiro do Norte, CE (Brazil); Mizrahi, S. S. [Departamento de Fisica, Universidade Federal de Sao Carlos, 13565-905 Sao Carlos, SP (Brazil); Moussa, M. H. Y. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Caixa Postal 369, 13560-590 Sao Carlos, SP (Brazil)

    2011-07-15

    In this paper we provide a recipe for state protection in a network of oscillators under collective damping and diffusion. Our strategy is to manipulate the network topology, i.e., the way the oscillators are coupled together, the strength of their couplings, and their natural frequencies, in order to create a relaxation-diffusion-free channel. This protected channel defines a decoherence-free subspace (DFS) for nonzero-temperature reservoirs. Our development also furnishes an alternative approach to build up DFSs that offers two advantages over the conventional method: it enables the derivation of all the network-protected states at once, and also reveals, through the network normal modes, the mechanism behind the emergence of these protected domains.

  10. Reduction of phosphorus diffusion in germanium by fluorine implantation

    SciTech Connect (OSTI)

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

    2013-12-14

    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.

  11. A Convergent Reaction-Diffusion Master Equation

    E-Print Network [OSTI]

    Samuel A Isaacson

    2013-06-28

    The reaction-diffusion master equation (RDME) is a lattice stochastic reaction-diffusion model that has been used to study spatially distributed cellular processes. The RDME is often interpreted as an approximation to spatially-continuous models in which molecules move by Brownian motion and react by one of several mechanisms when sufficiently close. In the limit that the lattice spacing approaches zero, in two or more dimensions, the RDME has been shown to lose bimolecular reactions. The RDME is therefore not a convergent approximation to any spatially-continuous model that incorporates bimolecular reactions. In this work we derive a new convergent RDME (CRDME) by finite volume discretization of a spatially-continuous stochastic reaction-diffusion model popularized by Doi. We demonstrate the numerical convergence of reaction time statistics associated with the CRDME. For sufficiently large lattice spacings or slow bimolecular reaction rates, we also show the reaction time statistics of the CRDME may be approximated by those from the RDME. The original RDME may therefore be interpreted as an approximation to the CRDME in several asymptotic limits.

  12. BDP: BrainSuite Diffusion Pipeline

    E-Print Network [OSTI]

    Leahy, Richard M.

    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

  13. Portable vapor diffusion coefficient meter

    DOE Patents [OSTI]

    Ho, Clifford K. (Albuquerque, NM)

    2007-06-12

    An apparatus for measuring the effective vapor diffusion coefficient of a test vapor diffusing through a sample of porous media contained within a test chamber. A chemical sensor measures the time-varying concentration of vapor that has diffused a known distance through the porous media. A data processor contained within the apparatus compares the measured sensor data with analytical predictions of the response curve based on the transient diffusion equation using Fick's Law, iterating on the choice of an effective vapor diffusion coefficient until the difference between the predicted and measured curves is minimized. Optionally, a purge fluid can forced through the porous media, permitting the apparatus to also measure a gas-phase permeability. The apparatus can be made lightweight, self-powered, and portable for use in the field.

  14. Sooting Behaviour Dynamics of a Non-Bouyant Laminar Diffusion Flame 

    E-Print Network [OSTI]

    Fuentes, Andres; Legros, Guillaume; Rouvreau, Sebastien; Joulain, Pierre; Vantelon, Jean-Pierre; Torero, Jose L; Fernandez-Pello, Carlos

    2007-01-01

    Local soot concentrations in non-buoyant laminar diffusion flames have been demonstrated to be the outcome of two competitive processes, soot formation and soot oxidation. It was first believed that soot formation was the controlling mechanism...

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

    E-Print Network [OSTI]

    Murawski, Matthew Thomas

    2001-01-01

    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...

  16. Diffuser for augmenting a wind turbine

    DOE Patents [OSTI]

    Foreman, Kenneth M. (North Bellmore, NY); Gilbert, Barry L. (Westbury, NY)

    1984-01-01

    A diffuser for augmenting a wind turbine having means for energizing the boundary layer at several locations along the diffuser walls is improved by the addition of a short collar extending radially outward from the outlet of the diffuser.

  17. Prediction of Room Air Diffusion for Reduced Diffuser Flow Rates 

    E-Print Network [OSTI]

    Gangisetti, Kavita

    2011-02-22

    are compared against the measured data. Other important parameters such as diffuser jet inlet angle and radiation effect are also considered on the benchmark case to validate the results and to recommend the best fit parameters for room air simulations...

  18. School science project 'demystifies' Portsmouth Gaseous Diffusion...

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

    School science project 'demystifies' Portsmouth Gaseous Diffusion Plant Site School science project 'demystifies' Portsmouth Gaseous Diffusion Plant Site June 2, 2015 - 10:40am...

  19. Independent Oversight Review, Portsmouth Gaseous Diffusion Plant...

    Office of Environmental Management (EM)

    January 2013 Independent Oversight Review, Portsmouth Gaseous Diffusion Plant - January 2013 January 2013 Review of the Portsmouth Gaseous Diffusion Plant Work Planning and Control...

  20. Independent Activity Report, Portsmouth Gaseous Diffusion Plant...

    Office of Environmental Management (EM)

    Portsmouth Gaseous Diffusion Plant - August 2011 Independent Activity Report, Portsmouth Gaseous Diffusion Plant - August 2011 August 2011 Orientation Visit to the Portsmouth...

  1. Concentration-Dependent Diffusion Instability in Reactive Miscible Fluids

    E-Print Network [OSTI]

    Bratsun, Dmitry; Mizev, Alexey; Mosheva, Elena

    2015-01-01

    We report new chemoconvective pattern formation phenomena observed in a two-layer system of miscible fluids filling a vertical Hele-Shaw cell. We show both experimentally and theoretically that the concentration-dependent diffusion coupled with the frontal acid-base neutralization can give rise to formation of the local unstable zone low in density resulting in a perfectly regular cell-type convective pattern. The described effect gives an example of yet another powerful mechanism which allows the reaction-diffusion processes to govern the flow of reacting fluids under gravity condition.

  2. Hot carrier diffusion in graphene

    E-Print Network [OSTI]

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

    2010-11-01

    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...

  3. & Mechanical Engineering

    E-Print Network [OSTI]

    Zhou, Chongwu

    AME Aerospace & Mechanical Engineering #12;Aerospace and Mechanical Engineers design complex mechanical, thermal, uidic, acoustical, optical, and electronic systems, with characteristic sizes ranging and far underground, to near-Earth, planetary, interplanetary and galactic space. Aerospace and Mechanical

  4. Mechanisms of Borderline Personality Disorder: The Role of Identity Diffusion 

    E-Print Network [OSTI]

    Lowmaster, Sara Elizabeth

    2013-08-06

    Borderline personality disorder (BPD) is a disabling psychiatric condition that causes pervasive and enduring impairments in social and occupational functioning. Previous literature has outlined the core components of the disorder to include...

  5. DIFFUSING ACOUSTIC WAVE TRANSPORT AND SPECTROSCOPY

    E-Print Network [OSTI]

    Page, John

    1 Chapter DIFFUSING ACOUSTIC WAVE TRANSPORT AND SPECTROSCOPY J.H. PAGE, M.L. COWAN Dept. of Physics waves, multiple scattering, energy velocity, Diffusing Acoustic Wave Spectroscopy. Abstract the diffusive transport of ultrasonic waves, and then describe a new ultrasonic technique, Diffusing Acoustic

  6. Computer simulation of grain boundary self-diffusion in aluminum

    SciTech Connect (OSTI)

    Dragunov, Andrei S., E-mail: andrei.dragunov@aun.edu.ng [American University of Nigeria, Nigeria, Adamawa State, Yola Yola By-Pass 98 Lamido Zubairu Way (Nigeria); Weckman, A. V.; Demyanov, B. F. [Altai State Technical University, Russia, Altai Region, Barnaul (Russian Federation)

    2014-10-06

    In the work study the process of self-diffusion in symmetric tilt grain boundaries (GB) with the axes misorientation [100], [110] and [111]. The research was carried out by the methods of computer simulation The objects of the research are the three GB of common and special type for each axis misorientation. The angles of misorientation of the common GB is amounted to 10°, 30° and 50°. The simulation was performed by the method of molecular dynamics in the temperature range from 600 to 1000 K, with an interval of 50 K. For research on the direction jumps atoms were built tracks the movement of atoms in the process of self-diffusion. The calculations have shown, that for all of GB is characterized by pronounced anisotropy of the jumps at low temperatures (< 700K). At temperatures near to the melting point directions of the jumps are isotropic only for three GB (?=30°[100], ?=50=[100] and ?5(013)[100]). For other GB such as [100] and [110] remains priority direction of diffusion along the nuclei GB dislocations. Arrenius curves have from one to three linear plots with different tilt. Change the tilt of Arrenius dependences testifies to the change in the mechanism of self-diffusion. The parameters of grainboundary self-diffusion were determined The activation energy of grainboundary diffusion in 4–5 times lower than the energy of activation of a volume self-diffusion of aluminum (about 200 KJ/mol). The minimum value of activation energy has GB 10° with the axis misorientation [100] (10,15 KJ/mol), maximum (104.12 Kj/mol) - a special GB ?11(113)

  7. Commercial Building Partnerships Replication and Diffusion

    SciTech Connect (OSTI)

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

    2013-09-16

    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.

  8. AMEAerospace & Mechanical

    E-Print Network [OSTI]

    Wang, Hai

    , emerging fuel cell technolo- gies, computational fluid mechanics, ground vehicle aerodynamics, combustion students develop problem solving skills in the areas of mechanics, thermody- namics, fluid mechanics, heat advance our understanding of such areas as continuum and particulate fluid mechanics, flight mechanics

  9. Bohmian Mechanics

    E-Print Network [OSTI]

    Detlef Duerr; Sheldon Goldstein; Roderich Tumulka; Nino Zanghi

    2009-03-15

    Bohmian mechanics is a theory about point particles moving along trajectories. It has the property that in a world governed by Bohmian mechanics, observers see the same statistics for experimental results as predicted by quantum mechanics. Bohmian mechanics thus provides an explanation of quantum mechanics. Moreover, the Bohmian trajectories are defined in a non-conspiratorial way by a few simple laws.

  10. Introduction Epidemic virus diffusion: models Epidemic algorithms Gossip algorithms Epidemic Information Diffusion on

    E-Print Network [OSTI]

    Ricci, Laura

    Introduction Epidemic virus diffusion: models Epidemic algorithms Gossip algorithms EpidemicD in Computer Science #12;Introduction Epidemic virus diffusion: models Epidemic algorithms Gossip algorithms Outline 1 Introduction 2 Epidemic virus diffusion: models 3 Epidemic algorithms 4 Gossip algorithms #12

  11. Stability and surface diffusion at lithium-electrolyte interphases with connections to dendrite suppression

    E-Print Network [OSTI]

    Ozhabes, Yalcin; Arias, T A

    2015-01-01

    This work presents an ab initio exploration of fundamental mechanisms with direct relevance to dendrite formation at lithium-electrolyte interfaces. Specifically, we explore surface diffusion barriers and solvated surface energies of typical solid-electrolyte interphase layers of lithium metal electrodes. Our results indicate that surface diffusion is an important mechanism for understanding the recently observed dendrite suppression from lithium-halide passivating layers, which were motivated by our previous work. Our results uncover possible mechanisms underlying a new pathway for mitigating dendridic electrodeposition of lithium on metal and thereby contribute to the ongoing efforts to develop stable lithium metal anodes for rechargeable battery systems.

  12. Intracellular facilitated diffusion: searchers, crowders and blockers

    E-Print Network [OSTI]

    C. A. Brackley; M. E. Cates; D. Marenduzzo

    2013-09-04

    In bacteria, regulatory proteins search for a specific DNA binding target via "facilitated diffusion": a series of rounds of 3D diffusion in the cytoplasm, and 1D linear diffusion along the DNA contour. Using large scale Brownian dynamics simulations we find that each of these steps is affected differently by crowding proteins, which can either be bound to the DNA acting as a road block to the 1D diffusion, or freely diffusing in the cytoplasm. Macromolecular crowding can strongly affect mechanistic features such as the balance between 3D and 1D diffusion, but leads to surprising robustness of the total search time.

  13. Tracer diffusion of hard-sphere binary mixtures under nano-confinement

    E-Print Network [OSTI]

    Umberto Marini Bettolo Marconi; Paolo Malgaretti; Ignacio Pagonabarraga

    2015-09-29

    The physics of diffusion phenomena in nano and micro channels has attracted a lot of attention in recent years, due to its close connection with many technological, medical and industrial applications. In the present paper we employ a kinetic approach to investigate how the confinement in nanostructured geometries affects the diffusive properties of fluid mixtures and leads to the appearance of properties different from those of bulk systems. In particular, we derive an expression for the friction tensor in the case of a bulk fluid mixture confined to a narrow slit having undulated walls. The boundary roughness leads to a new mechanism for transverse diffusion, and can even lead to an effective diffusion along the channel larger than the one corresponding to a planar channel of equivalent section. Finally we discuss a reduction of the previous equation to a one dimensional effective diffusion equation in which an entropic term encapsulates the geometrical information on the channel shape.

  14. Configurational diffusion of asphaltenes in fresh and aged catalyst extrudates. Final technical report, September 20, 1991--September 30, 1996

    SciTech Connect (OSTI)

    Guin, J.A.

    1998-12-31

    The overall objective of this project was to investigate the diffusion of coal and petroleum asphaltenes in the pores of a supported catalyst. Experimental measurements together with mathematical modeling was conducted to determine how the diffusion rate of asphaltenes, as well as some model compounds, depended on molecule sizes and shapes. The process of diffusion in the pores of a porous medium may occur by several mechanisms. Hindered diffusion occurs when the sizes of the diffusion molecules are comparable to those of the porous pores through which they are diffusing. Hindered diffusion phenomena have been widely observed in catalytic hydrotreatment of asphaltenes, heavy oils, coal derived liquids, etc. Pore diffusion limitations can be greater in spent catalysts due to the deposition of coke and metals in the pores. In this work, a general mathematical model was developed for the hindered diffusion-adsorption of solute in a solvent onto porous materials, e. g. catalysts, from a surrounding bath. This diffusion model incorporated the nonuniformities of pore structures in the porous media. A numerical method called the Method of Lines was used to solve the nonlinear partial differential equations resulting from the mathematical model. The accuracy of the numerical solution was verified by both a mass balance in the diffusion system and satisfactory agreement with known solutions in several special cases.

  15. Flame Height Measurement of Laminar Inverse Diffusion Flames

    E-Print Network [OSTI]

    Mikofski, Mark A.; Williams, Timothy C.; Shaddix, Christopher R.; Blevins, Linda G.

    2006-01-01

    Flame Height Measurement of Laminar Inverse Diffusion Flamesinverse diffusion flame, laminar, flame height, OH, laserair and methane-air laminar inverse diffusion flames were

  16. Synergistic diffuser/heat-exchanger design

    E-Print Network [OSTI]

    Lazzara, David S. (David Sergio), 1980-

    2004-01-01

    The theoretical and numerical evaluation of synergistic diffusing heat-exchanger design is presented. Motivation for this development is based on current diffuser and heat-exchange technologies in cogeneration plants, which ...

  17. MICROFLUIDIC CONTROL OF STEM CELL DIFFUSIBLE SIGNALING

    E-Print Network [OSTI]

    Voldman, Joel

    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

  18. Analysis and calibration of social factors in a consumer acceptance and adoption model for diffusion of diesel vehicle in Europe

    E-Print Network [OSTI]

    Zhang, Qi, S.M. Massachusetts Institute of Technology

    2008-01-01

    While large scale diffusion of alternative fuel vehicles (AFVs) is widely anticipated, the mechanisms that determine their success or failure are ill understood. Analysis of an AFV transition model developed at MIT has ...

  19. Bohmian mechanics contradicts quantum mechanics

    E-Print Network [OSTI]

    Neumaier, Arnold

    Bohmian mechanics contradicts quantum mechanics Arnold Neumaier Institut fur Mathematik, Universit://solon.cma.univie.ac.at/#24;neum/ Abstract. It is shown that, for a harmonic oscillator in the ground state, Bohmian mechanics and quantum mechanics predict values of opposite sign for certain time correlations. The discrepancy can

  20. Kinetic Structure of the Electron Diffusion Region in Antiparallel Magnetic Reconnection

    SciTech Connect (OSTI)

    Ng, J.; Egedal, J.; Le, A.; Daughton, W.; Chen, L.-J.

    2011-02-11

    Strong electron pressure anisotropy has been observed upstream of electron diffusion regions during reconnection in Earth's magnetotail and kinetic simulations. For collisionless antiparallel reconnection, we find that the anisotropy drives the electron current in the electron diffusion region, and that this current is insensitive to the reconnection electric field. Reconstruction of the electron distribution function within this region at enhanced resolutions reveals its highly structured nature and the mechanism by which the pressure anisotropy sets the structure of the region.

  1. Heat Hyperbolic Diffusion in Planck Gas

    E-Print Network [OSTI]

    Miroslaw Kozlowski; Janina Marciak-Kozlowska

    2006-07-06

    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

  2. Diffusion Tubes for Ambient NO2 Monitoring

    E-Print Network [OSTI]

    Short, Daniel

    2 Monitoring: Practical Guidance AEA Energy & Environment iii Foreword Palmes-type diffusion tubesDiffusion Tubes for Ambient NO2 Monitoring: Practical Guidance for Laboratories and Users Report Monitoring: Practical Guidance AEA/ENV/R/2504 ­ Issue 1a Title Diffusion Tubes for Ambient NO2 Monitoring

  3. “Electrochemical Shock” of Intercalation Electrodes: A Fracture Mechanics Analysis

    E-Print Network [OSTI]

    Chiang, Yet-Ming

    Fracture of electrode particles due to diffusion-induced stress has been implicated as a possible mechanism for capacity fade and impedance growth in lithium-ion batteries. In brittle materials, including many lithium ...

  4. Predicting X-ray diffuse scattering from translation–libration–screw structural ensembles

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

    Van Benschoten, Andrew H.; Afonine, Pavel V.; Terwilliger, Thomas C.; Wall, Michael E.; Jackson, Colin J.; Sauter, Nicholas K.; Adams, Paul D.; Urzhumtsev, Alexandre; Fraser, James S.

    2015-07-28

    Identifying the intramolecular motions of proteins and nucleic acids is a major challenge in macromolecular X-ray crystallography. Because Bragg diffraction describes the average positional distribution of crystalline atoms with imperfect precision, the resulting electron density can be compatible with multiple models of motion. Diffuse X-ray scattering can reduce this degeneracy by reporting on correlated atomic displacements. Although recent technological advances are increasing the potential to accurately measure diffuse scattering, computational modeling and validation tools are still needed to quantify the agreement between experimental data and different parameterizations of crystalline disorder. A new tool, phenix.diffuse, addresses this need by employing Guinier'smore »equation to calculate diffuse scattering from Protein Data Bank (PDB)-formatted structural ensembles. As an example case, phenix.diffuse is applied to translation–libration–screw (TLS) refinement, which models rigid-body displacement for segments of the macromolecule. To enable the calculation of diffuse scattering from TLS-refined structures, phenix.tls_as_xyz builds multi-model PDB files that sample the underlying T, L and S tensors. In the glycerophosphodiesterase GpdQ, alternative TLS-group partitioning and different motional correlations between groups yield markedly dissimilar diffuse scattering maps with distinct implications for molecular mechanism and allostery. These methods demonstrate how, in principle, X-ray diffuse scattering could extend macromolecular structural refinement, validation and analysis.« less

  5. Configurational diffusion of coal macromolecules

    SciTech Connect (OSTI)

    Guin, J.A.; Curtis, C.W.; Tarrer, A.R.; Kim, S.; Hwang, D.; Chen, C.C.; Chiou, Z.

    1991-01-01

    The objective of our research was to obtain fundamental information regarding the functional dependence of the diffusion coefficient of coal molecules on the ratio of molecule to pore diameter. That is, the objective of our study was to examine the effect of molecule size and configuration on hindered diffusion of coal macromolecules through as porous medium. To best accomplish this task, we circumvented the complexities of an actual porous catalyst by using a well defined porous matrix with uniform capillaric pores, i.e., a track-etched membrane. In this way, useful information was obtained regarding the relationship of molecular size and configuration on the diffusion rate of coal derived macromolecules through a pore structure with known geometry. Similar studies were performed using a pellet formed of porous alumina, to provide a link between the idealized membranes and the actual complex pore structure of real catalyst extrudates. The fundamental information from our study will be useful toward the tailoring of catalysts to minimize diffusional influences and thereby increase coal conversion and selectivity for desirable products. (VC)

  6. The mechanisms underlying convergent evolution in the plumage patterns of birds

    E-Print Network [OSTI]

    Gluckman, Thanh-Lan

    2015-03-03

    receptors (Yoshihara et al. 2012). Models of within-feather pattern formation The proposed organizing mechanism for within-feather pattern formation in birds is reaction-diffusion, based on Alan Turing’s (1952) original proposition The mechanisms...

  7. Effects of multi-component diffusion and heat release on laminar diffusion flame liftoff

    SciTech Connect (OSTI)

    Li, Zhiliang; Chen, Ruey-Hung [Department of Mechanical, Materials and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States); Phuoc, Tran X. [National Energy Technology Laboratory, Department of Energy, P.O. Box 10940, MS 84-340, Pittsburgh, PA 15261 (United States)

    2010-08-15

    Numerical simulations were conducted of the liftoff and stabilization phenomena of laminar jet diffusion flames of inert-diluted C{sub 3}H{sub 8} and CH{sub 4} fuels. Both non-reacting and reacting jets were investigated, including multi-component diffusivities and heat release effects (buoyancy and gas expansion). The role of Schmidt number for non-reacting jets was investigated, with no conclusive Schmidt number criterion for liftoff previously arrived at in similarity solutions. The cold-flow simulation for He-diluted CH{sub 4} fuel does not predict flame liftoff; however, adding heat release reaction lead to the prediction of liftoff, which is consistent with experimental observations. Including reaction was also found to improve liftoff height prediction for C{sub 3}H{sub 8} flames, with the flame base location differing from that in the similarity solution - the intersection of the stoichiometric and iso-velocity (equal to 1-D flame speed) is not necessary for flame stabilization (and thus liftoff). Possible mechanisms other than that proposed for similarity solution may better help to explain the stabilization and liftoff phenomena. (author)

  8. Ag Out-surface Diffusion In Crystalline SiC With An Effective SiO2 Diffusion Barrier

    SciTech Connect (OSTI)

    Xue, H.; Xiao, Haiyan Y.; Zhu, Zihua; Shutthanandan, V.; Snead, Lance L.; Boatner, Lynn A.; Weber, William J.; Zhang, Y.

    2015-09-01

    For applications of tristructural isotropic (TRISO) fuel particles in high temperature reactors, release of radioactive Ag isotope (110mAg) through the SiC coating layer is a safety concern. To understand the diffusion mechanism, Ag ion implantations near the surface and in the bulk were performed by utilizing different ion energies and energy-degrader foils. High temperature annealing was carried out on the as-irradiated samples to study the possible out-surface diffusion. Before and after annealing, Rutherford backscattering spectrometry (RBS) and secondary ion mass spectrometry (SIMS) measurements were employed to obtain the elemental profiles of the implanted samples. The results suggest little migration of buried Ag in the bulk, and an out-diffusion of the implanted Ag in the near-surface region of single crystal SiC. It is also found that a SiO2 layer, which was formed during annealing, may serve as an effective barrier to reduce or prevent Ag out diffusion through the SiC coating layer.

  9. Quantifying protein diffusion and capture on filaments

    E-Print Network [OSTI]

    Emanuel Reithmann; Louis Reese; Erwin Frey

    2015-03-03

    The functional relevance of regulating proteins is often limited to specific binding sites such as the ends of microtubules or actin-filaments. A localization of proteins on these functional sites is of great importance. We present a quantitative theory for a diffusion and capture process, where proteins diffuse on a filament and stop diffusing when reaching the filament's end. It is found that end-association after one-dimensional diffusion is the main source for tip-localization of such proteins. As a consequence, diffusion and capture is highly efficient in enhancing the reaction velocity of enzymatic reactions, where proteins and filament ends are to each other as enzyme and substrate. We show that the reaction velocity can effectively be described within a Michaelis-Menten framework. Together one-dimensional diffusion and capture beats the (three-dimensional) Smoluchowski diffusion limit for the rate of protein association to filament ends.

  10. Quantifying protein diffusion and capture on filaments

    E-Print Network [OSTI]

    Reithmann, Emanuel; Frey, Erwin

    2015-01-01

    The functional relevance of regulating proteins is often limited to specific binding sites such as the ends of microtubules or actin-filaments. A localization of proteins on these functional sites is of great importance. We present a quantitative theory for a diffusion and capture process, where proteins diffuse on a filament and stop diffusing when reaching the filament's end. It is found that end-association after one-dimensional diffusion is the main source for tip-localization of such proteins. As a consequence, diffusion and capture is highly efficient in enhancing the reaction velocity of enzymatic reactions, where proteins and filament ends are to each other as enzyme and substrate. We show that the reaction velocity can effectively be described within a Michaelis-Menten framework. Together one-dimensional diffusion and capture beats the (three-dimensional) Smoluchowski diffusion limit for the rate of protein association to filament ends.

  11. MODEL OF DIFFUSERS / PERMEATORS FOR HYDROGEN PROCESSING

    SciTech Connect (OSTI)

    Hang, T; William Jacobs, W

    2007-08-27

    Palladium-silver (Pd-Ag) diffusers are mainstays of hydrogen processing. Diffusers separate hydrogen from inert species such as nitrogen, argon or helium. The tubing becomes permeable to hydrogen when heated to more than 250 C and a differential pressure is created across the membrane. The hydrogen diffuses better at higher temperatures. Experimental or experiential results have been the basis for determining or predicting a diffuser's performance. However, the process can be mathematically modeled, and comparison to experimental or other operating data can be utilized to improve the fit of the model. A reliable model-based diffuser system design is the goal which will have impacts on tritium and hydrogen processing. A computer model has been developed to solve the differential equations for diffusion given the operating boundary conditions. The model was compared to operating data for a low pressure diffuser system. The modeling approach and the results are presented in this paper.

  12. Supporting information Vapor Phase Synthesis of Single-Crystalline Ag Nanowires and Single-

    E-Print Network [OSTI]

    Ihee, Hyotcherl

    NWs. Figure S3 shows the home-made microRaman system, which was based on an Olympus BX41 microscope. Figure S3. Micro-Raman system for the measurement of SERS of Ag NWs. A 514.5 nm Ar-ion laser light direction of the incident laser light. The laser light was focused on a NW through an objective (Mitutoyo M

  13. Chirality-Dependent Vapor-Phase Epitaxial Growth and Termination of Single-Wall Carbon Nanotubes

    E-Print Network [OSTI]

    Zhou, Chongwu

    cylinders from graphene sheets.1 The structure of a SWCNT is uniquely determined by a pair of integers, (n and optical characteristics of SWCNTs rely on their chiralities,2,3 and chirality-controlled preparation

  14. Sulfurization of carbon surface for vapor phase mercury removal I: Effect of temperature and sulfurization protocol

    E-Print Network [OSTI]

    Borguet, Eric

    a fixed bed reactor system to determine the effects of sorbent properties, temperature (200­800 °C; Impregnation; Temperature programmed desorption; Surface properties 1. Introduction Hydrogen sulfide, such as the Integrated Gasification Combined Cycle (IGCC) process [4], and the coal gas cleaning process [5], removal

  15. Interrupted Energy Transfer: Highly Selective Detection of Cyclic Ketones in the Vapor Phase

    E-Print Network [OSTI]

    Swager, Timothy Manning

    We detail our efforts toward the selective detection of cyclic ketones, e.g. cyclohexanone, a component of plasticized explosives. Thin films comprised of a conjugated polymer are used to amplify the emission of an emissive ...

  16. The particulate and vapor phase components of airborne polyaromatic hydrocarbons (PAHs) in coal gasification pilot plants 

    E-Print Network [OSTI]

    Brink, Eric Jon

    1980-01-01

    gas, ammonia, and other chemicals from coal. For example, coal is being gasified today in Turkey, India, South Africa, Scotland, Morocco, Yugoslavia, and Korea, Coal conversion was a large scale operation in Germany in World War II and supplied 85... on the process, such as: process options, type of coal feedstock, gasifier operational mode, and purification processes. However, there are similarities that permit a discussion of the fundamental process steps. A block diagram of a generalized coal...

  17. ICES REPORT 15-14 Liquid-Vapor Phase Transition: Thermomechanical

    E-Print Network [OSTI]

    ICES

    -order time-accurate. Isogeometric analysis is utilized for spatial discretization. The analytical properties, Phase transition, Evaporation, Condensation, Boiling 1 #12;1 Introduction 1.1 Phase transition induced by temperature variations can be observed in daily life as boiling, evaporation, and condensation

  18. Liquid-phase and vapor-phase dehydration of organic/water solutions

    DOE Patents [OSTI]

    Huang, Yu (Palo Alto, CA); Ly, Jennifer (San Jose, CA); Aldajani, Tiem (San Jose, CA); Baker, Richard W. (Palo Alto, CA)

    2011-08-23

    Processes for dehydrating an organic/water solution by pervaporation or vapor separation using fluorinated membranes. The processes are particularly useful for treating mixtures containing light organic components, such as ethanol, isopropanol or acetic acid.

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

    E-Print Network [OSTI]

    Lee, Jongho

    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 ...

  20. The role of polymer formation during vapor phase lubrication of silicon.

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)FeedbackPropertiesfully coupledU(VI)-contaminated(Conference) | SciTech

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

    SciTech Connect (OSTI)

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

    2011-02-01

    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.

  2. Bulk and surface controlled diffusion of fission gas atoms

    SciTech Connect (OSTI)

    Andersson, Anders D.

    2012-08-09

    Fission gas retention and release impact nuclear fuel performance by, e.g., causing fuel swelling leading to mechanical interaction with the clad, increasing the plenum pressure and reducing the gap thermal conductivity. All of these processes are important to understand in order to optimize operating conditions of nuclear reactors and to simulate accident scenarios. Most fission gases have low solubility in the fuel matrix, which is especially pronounced for large fission gas atoms such as Xe and Kr, and as a result there is a significant driving force for segregation of gas atoms to extended defects such as grain boundaries or dislocations and subsequently for nucleation of gas bubbles at these sinks. Several empirical or semi-empirical models have been developed for fission gas release in nuclear fuels, e.g. [1-6]. One of the most commonly used models in fuel performance codes was published by Massih and Forsberg [3,4,6]. This model is similar to the early Booth model [1] in that it applies an equivalent sphere to separate bulk UO{sub 2} from grain boundaries represented by the sphere circumference. Compared to the Booth model, it also captures trapping at grain boundaries, fission gas resolution and it describes release from the boundary by applying timedependent boundary conditions to the circumference. In this work we focus on the step where fission gas atoms diffuse from the grain interior to the grain boundaries. The original Massih-Forsberg model describes this process by applying an effective diffusivity divided into three temperature regimes. In this report we present results from density functional theory calculations (DFT) that are relevant for the high (D{sub 3}) and intermediate (D{sub 2}) temperature diffusivities of fission gases. The results are validated by making a quantitative comparison to Turnbull's [8-10] and Matzke's data [12]. For the intrinsic or high temperature regime we report activation energies for both Xe and Kr diffusion in UO{sub 2{+-}x}, which compare favorably to available experiments. This is an extension of previous work [13]. In particular, it applies improved chemistry models for the UO{sub 2{+-}x} nonstoichiometry and its impact on the fission gas activation energies. The derivation of these models follows the approach that used in our recent study of uranium vacancy diffusion in UO{sub 2} [14]. Also, based on the calculated DFT data we analyze vacancy enhanced diffusion mechanisms in the intermediate temperature regime. In addition to vacancy enhanced diffusion we investigate species transport on the (111) UO{sub 2} surface. This is motivated by the formation of small voids partially filled with fission gas atoms (bubbles) in UO{sub 2} under irradiation, for which surface diffusion could be the rate-limiting transport step. Diffusion of such bubbles constitutes an alternative mechanism for mass transport in these materials.

  3. Mechanical Engineering 1 Mechanical Engineering

    E-Print Network [OSTI]

    Haller, Gary L.

    , for example, in novel gas turbine or electric hybrid vehicles--require that students understand the fundamentals of mechanics, thermodynamics, fluid mechanics, combustion, and materials science. In all members of the next generation of mechanical engineers. To implement this mission, the department adheres

  4. Dynamics of Mesoscale Magnetic Field in Diffusive Shock Acceleration

    E-Print Network [OSTI]

    P. H. Diamond; M. A. Malkov

    2006-05-15

    We present a theory for the generation of mesoscale ($kr_{g}\\ll 1$, where $r_{g}$ is the cosmic ray gyroradius) magnetic fields during diffusive shock acceleration. The decay or modulational instability of resonantly excited Alfven waves scattering off ambient density perturbations in the shock environment naturally generates larger scale fields. For a broad spectrum of perturbations, the physical mechanism of energy transfer is random refraction, represented by diffusion of Alfven wave packet in $k-$space. The scattering field can be produced directly by the decay instability or by the Drury instability, a hydrodynamic instability driven by the cosmic ray pressure gradient. This process is of interest to acceleration since it generates waves of longer wavelength, and so enables the confinement and acceleration of higher energy particles. This process also limits the intensity of resonantly generated turbulent magnetic field on $r_{g}$ scales.

  5. Bohmian mechanics contradicts quantum mechanics

    E-Print Network [OSTI]

    Arnold Neumaier

    2000-02-16

    It is shown that, for a harmonic oscillator in the ground state, Bohmian mechanics and quantum mechanics predict values of opposite sign for certain time correlations. The discrepancy can be explained by the fact that Bohmian mechanics has no natural way to accomodate the Heisenberg picture, since the local expectation values that define the beables of the theory depend on the Heisenberg time being used to define the operators. Relations to measurement are discussed, too, and shown to leave no loophole for claiming that Bohmian mechanics reproduces all predictions of quantum mechanics exactly.

  6. Experience with Palladium Diffusers in Tritium Processing

    SciTech Connect (OSTI)

    Motyka, T.; Clark, E.A.; Dauchess, D.A.; Heung, L.K.; Rabum, R.L.

    1995-01-27

    Hydrogen isotopes are separated from other gases by permeation through palladium and palladium-silver alloy diffusers in the Tritium Facilities at the US Department of Energy Savannah River Site (SRS). Diffusers have provided effective service for almost forty years. This paper is an overview of the operational experience with the various diffuser types that have been employed at SRS. Alternative technologies being developed at SRS for purifying hydrogen isotopes are also discussed.

  7. Nonlinear diffusion in Acetone-Benzene Solution

    E-Print Network [OSTI]

    Obukhovsky, Vjacheslav V

    2010-01-01

    The nonlinear diffusion in multicomponent liquids under chemical reactions influence has been studied. The theory is applied to the analysis of mass transfer in a solution of acetone-benzene. It has been shown, that the creation of molecular complexes should be taken into account for the explanation of the experimental data on concentration dependence of diffusion coefficients. The matrix of mutual diffusivities has been found and effective parameters of the system have been computed.

  8. Characterization of Fuel-Cell Diffusion Media

    E-Print Network [OSTI]

    Gunterman, Haluna Penelope Frances

    2011-01-01

    Characterization of Fuel-Cell Diffusion Media by HalunaFall 2011 Abstract Characterization of Fuel-Cell Diffusionpredictive capabilities. Characterization of DM and their

  9. Metal Nitride Diffusion Barriers for Copper Interconnects 

    E-Print Network [OSTI]

    Araujo, Roy A.

    2010-01-14

    Advancements in the semiconductor industry require new materials with improved performance. With the introduction of copper as the interconnect material for integrated circuits, efficient diffusion barriers are required ...

  10. Portsmouth Gaseous Diffusion Plant Director's Final Findings...

    Office of Environmental Management (EM)

    Portsmouth Gaseous Diffusion Plant Director's Final Findings and Orders, October 4, 1995 State Ohio Agreement Type Federal Facility Agreement Legal Driver(s) FFCAct Scope Summary...

  11. Independent Oversight Review, Portsmouth Gaseous Diffusion Plant...

    Office of Environmental Management (EM)

    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...

  12. Compliant mechanisms 

    E-Print Network [OSTI]

    Venkataraghavan, Janarthanan T

    2001-01-01

    and a few mechanisms like a magneto active peristaltic pump, have been designed and tested for the first time using this material. In this mechanism, the pumping action is obtained when a moving magnetic field produces peristaltic waves in the magneto...

  13. MECHANICAL ENGINEERING What is Mechanical

    E-Print Network [OSTI]

    power plant energy conversion and generating systems; design, development, and manufactureof consumer of the broadest engineering fields. Mechanical engineers are found in virtually all productive industries, from

  14. Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

    SciTech Connect (OSTI)

    R.E. Mizia; D.E. Clark; M.V. Glazoff; T.E. Lister; T.L. Trowbridge

    2011-12-01

    The U.S. Department of Energy selected the high temperature gas-cooled reactor as the basis for the Next Generation Nuclear Plant (NGNP). The NGNP will demonstrate the use of nuclear power for electricity, hydrogen production, and process heat applications. The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. An intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding. This report describes the preliminary results of a scoping study that evaluated the diffusion welding process parameters and the resultant mechanical properties of diffusion welded joints using Alloy 800H. The long-term goal of the program is to progress towards demonstration of small heat exchanger unit cells fabricated with diffusion welds. Demonstration through mechanical testing of the unit cells will support American Society of Mechanical Engineers rules and standards development, reduce technical risk, and provide proof of concept for heat exchanger fabrication methods needed to deploy heat exchangers in several potential NGNP configurations.1 Researchers also evaluated the usefulness of modern thermodynamic and diffusion computational tools (Thermo-Calc and Dictra) in optimizing the parameters for diffusion welding of Alloy 800H. The modeling efforts suggested a temperature of 1150 C for 1 hour with an applied pressure of 5 MPa using 15 {micro}m nickel foil as joint filler to reduce chromium oxidation on the welded surfaces. Good agreement between modeled and experimentally determined concentration gradients was achieved

  15. Anomalous diffusion in fractal globules

    E-Print Network [OSTI]

    Mikhail V. Tamm; Leonid I. Nazarov; Alexey A. Gavrilov; Alexander V. Chertovich

    2016-01-07

    The fractal globule state is a popular model for describing chromatin packing in eukaryotic nuclei. Here we provide a scaling theory and dissipative particle dynamics (DPD) computer simulation for the thermal motion of monomers in the fractal globule state. Simulations starting from different entanglement-free initial states show good convergence which provides evidence supporting the existence of unique metastable fractal globule state. We show monomer motion in this state to be sub-diffusive described by $\\langle X^2 (t)\\rangle \\sim t^{\\alpha_F}$ with $\\alpha_F$ close to 0.4. This result is in good agreement with existing experimental data on the chromatin dynamics which makes an additional argument in support of the fractal globule model of chromatin packing.

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

    E-Print Network [OSTI]

    Feigon, Brooke

    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

  17. Diffuse Surface Scattering in the Plasmonic Resonances of Ultra-Low Electron Density Nanospheres

    E-Print Network [OSTI]

    Monreal, R Carmina; Apell, S Peter

    2015-01-01

    Localized surface plasmon resonances (LSPRs) have recently been identified in extremely diluted electron systems obtained by doping semiconductor quantum dots. Here we investigate the role that different surface effects, namely electronic spill-out and diffuse surface scattering, play in the optical properties of these ultra-low electron density nanosystems. Diffuse scattering originates from imperfections or roughness at a microscopic scale on the surface. Using an electromagnetic theory that describes this mechanism in conjunction with a dielectric function including the quantum size effect, we find that the LSPRs show an oscillatory behavior both in position and width for large particles and a strong blueshift in energy and an increased width for smaller radii, consistent with recent experimental results for photodoped ZnO nanocrystals. We thus show that the commonly ignored process of diffuse surface scattering is a more important mechanism affecting the plasmonic properties of ultra-low electron density ...

  18. Mechanical memory

    DOE Patents [OSTI]

    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)

    2006-08-15

    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.

  19. Mechanical memory

    DOE Patents [OSTI]

    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)

    2006-05-16

    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.

  20. SNOW LINES AS PROBES OF TURBULENT DIFFUSION IN PROTOPLANETARY DISKS

    SciTech Connect (OSTI)

    Owen, James E. [Canadian Institute for Theoretical Astrophysics, 60 St George Street, Toronto, M5S 3H8, ON (Canada)

    2014-07-20

    Sharp chemical discontinuities can occur in protoplanetary disks, particularly at ''snow lines'' where a gas-phase species freezes out to form ice grains. Such sharp discontinuities will diffuse out due to the turbulence suspected to drive angular momentum transport in accretion disks. We demonstrate that the concentration gradient—in the vicinity of the snow line—of a species present outside a snow line but destroyed inside is strongly sensitive to the level of turbulent diffusion (provided the chemical and transport timescales are decoupled) and provides a direct measurement of the radial ''Schmidt number'' (the ratio of the angular momentum transport to radial turbulent diffusion). Taking as an example the tracer species N{sub 2}H{sup +}, which is expected to be destroyed inside the CO snow line (as recently observed in TW Hya) we show that ALMA observations possess significant angular resolution to constrain the Schmidt number. Since different turbulent driving mechanisms predict different Schmidt numbers, a direct measurement of the Schmidt number in accretion disks would allow inferences to be made about the nature of the turbulence.

  1. Thermal Expansion and Diffusion Coefficients of Carbon

    E-Print Network [OSTI]

    Wei, Chenyu

    Thermal Expansion and Diffusion Coefficients of Carbon Nanotube-Polymer Composites Chenyu Wei* NASA of carbon nanotube-polyethylene composites. Additions of carbon nanotubes to a polymer matrix are found for polymer-nanotube interface are used to investigate the thermal expansion and diffusion characteristics

  2. Finite-difference schemes for anisotropic diffusion

    SciTech Connect (OSTI)

    Es, Bram van; Koren, Barry; Blank, Hugo J. de

    2014-09-01

    In fusion plasmas diffusion tensors are extremely anisotropic due to the high temperature and large magnetic field strength. This causes diffusion, heat conduction, and viscous momentum loss, to effectively be aligned with the magnetic field lines. This alignment leads to different values for the respective diffusive coefficients in the magnetic field direction and in the perpendicular direction, to the extent that heat diffusion coefficients can be up to 10{sup 12} times larger in the parallel direction than in the perpendicular direction. This anisotropy puts stringent requirements on the numerical methods used to approximate the MHD-equations since any misalignment of the grid may cause the perpendicular diffusion to be polluted by the numerical error in approximating the parallel diffusion. Currently the common approach is to apply magnetic field-aligned coordinates, an approach that automatically takes care of the directionality of the diffusive coefficients. This approach runs into problems at x-points and at points where there is magnetic re-connection, since this causes local non-alignment. It is therefore useful to consider numerical schemes that are tolerant to the misalignment of the grid with the magnetic field lines, both to improve existing methods and to help open the possibility of applying regular non-aligned grids. To investigate this, in this paper several discretization schemes are developed and applied to the anisotropic heat diffusion equation on a non-aligned grid.

  3. Thermal diffusion shock waves Sorasak Danworaphong1

    E-Print Network [OSTI]

    Craig, Walter

    Thermal diffusion shock waves Sorasak Danworaphong1 , Walter Craig3 , Vitalyi Gusev4 , and Gerald J and are concentrated by a thermal gradient imposed on a salt solution, the separation of the components of a mixture in a thermal field, known as "thermal diffusion", or the Ludwig-Soret effect has been found not only in liquids

  4. Model for Diffusion-Induced Ramsey Narrowing

    E-Print Network [OSTI]

    Alexander Romanenko; Leonid Yatsenko

    2008-01-22

    Diffusion-induced Ramsey narrowing that appears when atoms can leave the interaction region and repeatedly return without lost of coherence is investigated using strong collisions approximation. The effective diffusion equation is obtained and solved for low-dimensional model configurations and three-dimensional real one.

  5. Volumetric Modeling with Diffusion Surfaces Kenshi Takayama

    E-Print Network [OSTI]

    Igarashi, Takeo

    Volumetric Modeling with Diffusion Surfaces Kenshi Takayama The University of Tokyo Olga Sorkine ERATO Abstract The modeling of volumetric objects is still a difficult problem. Solid texture synthesis colors from nearby surfaces. A straightfor- ward way to compute color diffusion is to solve a volumetric

  6. EXISTENCE OF A SOLUTION IN AN AGE DEPENDENT TRANSPORT-DIFFUSION

    E-Print Network [OSTI]

    Pacard, Frank

    water treatment plant may include both transport and diffusion. When the residence time of sludge for the steady states of a settler (in a waste water treat- ment plant). This kind of equations is introduced. The settling mechanism is modeled in the term V , or sludge velocity. It includes the water velocity (depending

  7. Impact on the Indoor Environment of the Release and Diffusion of TVOC 

    E-Print Network [OSTI]

    Cong, X.; Liu, Y.; Wang, M.

    2006-01-01

    source. The control function of the mechanism mode is put forward according to the process of the TVOC under dry conditions within the room in this study. The function is made up of three parts: the diffusion transport function of VOCS in the material...

  8. Matrix rheology effects on reaction rim growth II: coupled diffusion and creep model

    E-Print Network [OSTI]

    Podladchikov, Yuri

    Matrix rheology effects on reaction rim growth II: coupled diffusion and creep model D. W. SCHMID,1 of the matrix that surrounds the reaction sites where the volume change takes place. Consequently, mineral reactions and the mechanical response of the rock matrix are coupled. A companion paper in this issue

  9. Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber-Reinforced Ceramic Composite

    E-Print Network [OSTI]

    Zok, Frank

    Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber-Reinforced Ceramic Composite conductances coupled with a unit cell model for a fiber composite containing a periodic array of matrix cracks tolerance and notch insensitivity in continuous fiber ceramic composites (CFCCs).1 These mechanisms play

  10. Study of lithium diffusion in RF sputtered Nickel/Vanadium mixed oxides thin films

    E-Print Network [OSTI]

    Artuso, Florinda

    Study of lithium diffusion in RF sputtered NickelÁ/Vanadium mixed oxides thin films F. Artuso a lithium insertion inside RF sputtered Ni/V mixed oxides thin films have been investigated employing, showed three steps clearly involved in the intercalation mechanism of lithium in the oxide films: (i

  11. Solid-state diffusion in amorphous zirconolite

    SciTech Connect (OSTI)

    Yang, C.; Dove, M. T.; Trachenko, K.; Zarkadoula, E.; Todorov, I. T.; Geisler, T.; Brazhkin, V. V.

    2014-11-14

    We discuss how structural disorder and amorphization affect solid-state diffusion, and consider zirconolite as a currently important case study. By performing extensive molecular dynamics simulations, we disentangle the effects of amorphization and density, and show that a profound increase of solid-state diffusion takes place as a result of amorphization. Importantly, this can take place at the same density as in the crystal, representing an interesting general insight regarding solid-state diffusion. We find that decreasing the density in the amorphous system increases pre-factors of diffusion constants, but does not change the activation energy in the density range considered. We also find that atomic species in zirconolite are affected differently by amorphization and density change. Our microscopic insights are relevant for understanding how solid-state diffusion changes due to disorder and for building predictive models of operation of materials to be used to encapsulate nuclear waste.

  12. Asymptotics for the maximum likelihood estimators of diffusion models 

    E-Print Network [OSTI]

    Jeong, Minsoo

    2009-05-15

    In this paper I derive the asymptotics of the exact, Euler, and Milstein ML estimators for diffusion models, including general nonstationary diffusions. Though there have been many estimators for the diffusion model, their asymptotic properties were...

  13. Microfluidic Investigation of Tracer Dye Diffusion in Alumina Nanofluids 

    E-Print Network [OSTI]

    Ozturk, Serdar 1979-

    2012-10-05

    on enhanced mass diffusion and the possibility of tailoring mass transport by direct manipulation of molecular diffusion. Therefore, a microfluidic approach capable of directly probing tracer diffusion between nanoparticle-laden fluid streams was developed...

  14. Measuring central-spin interaction with a spin bath by pulsed ENDOR: Towards suppression of spin diffusion decoherence

    E-Print Network [OSTI]

    S. J. Balian; M. B. A. Kunze; M. H. Mohammady; G. W. Morley; W. M. Witzel; C. W. M. Kay; T. S. Monteiro

    2012-10-08

    We present pulsed electron-nuclear double resonance (ENDOR) experiments which enable us to characterize the coupling between bismuth donor spin qubits in Si and the surrounding spin bath of 29Si impurities which provides the dominant decoherence mechanism (nuclear spin diffusion) at low temperatures (expansion simulations show near-complete suppression of spin diffusion, at optimal working points. The suppression takes the form of sharply peaked divergences of the spin diffusion coherence time, in contrast with previously identified broader regions of insensitivity to classical fluctuations. ENDOR data suggest that anisotropic contributions are comparatively weak, so the form of the divergences is largely independent of crystal orientation.

  15. Experimental Evidence Supported by Simulations of a Very High H{sub 2} Diffusion in Metal Organic Framework Materials

    SciTech Connect (OSTI)

    Salles, F.; Maurin, G.; Jobic, H.; Koza, M. M.; Llewellyn, P. L.; Devic, T.; Serre, C.; Ferey, G.

    2008-06-20

    Quasielastic neutron scattering measurements are combined with molecular dynamics simulations to extract the self-diffusion coefficient of hydrogen in the metal organic frameworks MIL-47(V) and MIL-53(Cr). We find that the diffusivity of hydrogen at low loading is about 2 orders of magnitude higher than in zeolites. Such a high mobility has never been experimentally observed before in any nanoporous materials, although it was predicted in carbon nanotubes. Either 1D or 3D diffusion mechanisms are elucidated depending on the chemical features of the MIL framework.

  16. Review of enhanced vapor diffusion in porous media

    SciTech Connect (OSTI)

    Webb, S.W.; Ho, C.K.

    1998-08-01

    Vapor diffusion in porous media in the presence of its own liquid has often been treated similar to gas diffusion. The gas diffusion rate in porous media is much lower than in free space due to the presence of the porous medium and any liquid present. However, enhanced vapor diffusion has also been postulated such that the diffusion rate may approach free-space values. Existing data and models for enhanced vapor diffusion, including those in TOUGH2, are reviewed in this paper.

  17. Diffusion and transport coefficients in synthetic opals

    SciTech Connect (OSTI)

    Sofo, J. O.; Mahan, G. D.; Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200

    2000-07-15

    Opals are structures composed of close-packed spheres in the size range of nano to micrometers. They are sintered to create small necks at the points of contact. We have solved the diffusion problem in such structures. The relation between the diffusion coefficient and the thermal and electrical conductivity is used to estimate the transport coefficients of opal structures as a function of the neck size and the mean free path of the carriers. The theory presented is also applicable to the diffusion problem in other periodic structures. (c) 2000 The American Physical Society.

  18. HINDERED DIFFUSION OF COAL LIQUIDS

    SciTech Connect (OSTI)

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

    1996-01-01

    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.

  19. Transport diffusion of liquid water and methanol through membranes...

    Office of Scientific and Technical Information (OSTI)

    Transport diffusion of liquid water and methanol through membranes Citation Details In-Document Search Title: Transport diffusion of liquid water and methanol through membranes The...

  20. Portsmouth Gaseous Diffusion Plant - Quadrant I Groundwater Investigat...

    Office of Environmental Management (EM)

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

  1. DOE Seeks Small Businesses for Paducah Gaseous Diffusion Plant...

    Office of Environmental Management (EM)

    Paducah Gaseous Diffusion Plant Infrastructure Support Services DOE Seeks Small Businesses for Paducah Gaseous Diffusion Plant Infrastructure Support Services June 10, 2014 -...

  2. DOE Issues Final Request for Proposal for Paducah Gaseous Diffusion...

    Energy Savers [EERE]

    Paducah Gaseous Diffusion Plant Support Services DOE Issues Final Request for Proposal for Paducah Gaseous Diffusion Plant Support Services October 6, 2014 - 4:13pm Addthis Media...

  3. DOE Awards Contract for Paducah Gaseous Diffusion Plant Infrastructure...

    Office of Environmental Management (EM)

    Paducah Gaseous Diffusion Plant Infrastructure Support Services DOE Awards Contract for Paducah Gaseous Diffusion Plant Infrastructure Support Services June 17, 2015 - 5:45pm...

  4. Low cost fuel cell diffusion layer configured for optimized anode...

    Office of Scientific and Technical Information (OSTI)

    Patent: Low cost fuel cell diffusion layer configured for optimized anode water management Citation Details In-Document Search Title: Low cost fuel cell diffusion layer configured...

  5. Biomedical Applications of NMR Imaging and Diffusion Studies

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    Biomedical Applications of NMR Imaging and Diffusion Studies Using Thermal And Hyperpolarized Xenon by ..................................................................................................... David Nelson Chairman, Department of Physics #12;Biomedical Applications of NMR Imaging and Diffusion

  6. Diffusion releases through one and two finite planar zones from...

    Office of Scientific and Technical Information (OSTI)

    Diffusion releases through one and two finite planar zones from a nuclear waste package Citation Details In-Document Search Title: Diffusion releases through one and two finite...

  7. Diffusion releases through one and two finite planar zones from...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: Diffusion releases through one and two finite planar zones from a nuclear waste package Citation Details In-Document Search Title: Diffusion releases through one...

  8. Novel applications of diffusion-driven flow

    E-Print Network [OSTI]

    Allshouse, Michael R

    2010-01-01

    Diffusion-driven flow is the result of a conflict between hydrostatic equilibrium in a density stratified fluid and the no-flux boundary condition that must be obeyed on impermeable boundaries that are sloping with respect ...

  9. Diffuse reflectance imaging with astronomical applications

    E-Print Network [OSTI]

    Hasinoff, Samuel W.

    Diffuse objects generally tell us little about the surrounding lighting, since the radiance they reflect blurs together incident lighting from many directions. In this paper we discuss how occlusion geometry can help invert ...

  10. Diffusion, dimensionality and noise in transcriptional regulation

    E-Print Network [OSTI]

    Gasper Tkacik; William Bialek

    2007-12-12

    The precision of biochemical signaling is limited by randomness in the diffusive arrival of molecules at their targets. For proteins binding to the specific sites on the DNA and regulating transcription, the ability of the proteins to diffuse in one dimension by sliding along the length of the DNA, in addition to their diffusion in bulk solution, would seem to generate a larger target for DNA binding, consequently reducing the noise in the occupancy of the regulatory site. Here we show that this effect is largely cancelled by the enhanced temporal correlations in one dimensional diffusion. With realistic parameters, sliding along DNA has surprisingly little effect on the physical limits to the precision of transcriptional regulation.

  11. Diffuser Augmented Wind Turbine Analysis Code

    E-Print Network [OSTI]

    Carroll, Jonathan

    2014-05-31

    , 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...

  12. Electrospray emitters For diffusion vacuum pumps

    E-Print Network [OSTI]

    Diaz Gómez Maqueo, Pablo (Pablo Ly)

    2011-01-01

    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 ...

  13. JUMP DIFFUSION OPTION WITH TRANSACTION COSTS

    E-Print Network [OSTI]

    Mocioalca, Oana

    JUMP DIFFUSION OPTION WITH TRANSACTION COSTS "non-systematic" risk, inclusive of transaction costs. We compute the total transac- tion costs and the turnover for different options, transaction costs, and revision intervals

  14. Excursions of diffusion processes and continued fractions

    E-Print Network [OSTI]

    Alain Comtet; Yves Tourigny

    2010-02-11

    It is well-known that the excursions of a one-dimensional diffusion process can be studied by considering a certain Riccati equation associated with the process. We show that, in many cases of interest, the Riccati equation can be solved in terms of an infinite continued fraction. We examine the probabilistic significance of the expansion. To illustrate our results, we discuss some examples of diffusions in deterministic and in random environments.

  15. Development of anomalous diffusion among crowding proteins

    E-Print Network [OSTI]

    Margaret R. Horton; Felix Höfling; Joachim O. Rädler; Thomas Franosch

    2010-03-19

    In cell membranes, proteins and lipids diffuse in a highly crowded and heterogeneous landscape, where aggregates and dense domains of proteins or lipids obstruct the path of diffusing molecules. In general, hindered motion gives rise to anomalous transport, though the nature of the onset of this behavior is still under debate and difficult to investigate experimentally. Here, we present a systematic study where proteins bound to supported lipid membranes diffuse freely in two dimensions, but are increasingly hindered by the presence of other like proteins. In our model system, the surface coverage of the protein avidin on the lipid bilayer is well controlled by varying the concentration of biotinylated lipid anchors. Using fluorescence correlation spectroscopy (FCS), we measure the time correlation function over long times and convert it to the mean-square displacement of the diffusing proteins. Our approach allows for high precision data and a clear distinction between anomalous and normal diffusion. It enables us to investigate the onset of anomalous diffusion, which takes place when the area coverage of membrane proteins increases beyond approximately 5%. This transition region exhibits pronounced spatial heterogeneities. Increasing the packing fraction further, transport becomes more and more anomalous, manifested in a decrease of the exponent of subdiffusion.

  16. Diffusivity of rocks: Gas diffusion measurements and correlation to porosity and pore size distribution

    E-Print Network [OSTI]

    Hu, Qinhong "Max"

    scenarios, such as geologic disposal of radioactive waste [Gillham et al., 1984], contaminant remediation [e been used to determine gas transport parameters includ- ing permeability, diffusion coefficient

  17. Fractofusion mechanism

    SciTech Connect (OSTI)

    Yasui, K. . Dept. of Physics)

    1992-11-01

    In this paper, the fractofusion mechanism of cold fusion is investigated theoretically. The conditions necessary for fractofusion during the absorption of deuterium atoms by palladium specimens (the condition of so-called cold fusion experiments) is clarified, including crack generation at grain boundaries, the high orientation angle of grains, rapid crack formation, the increase of electrical resistance around a crack, the large width of cracks, and the generation of many cracks. The origin and quantity of the electrical field inside cracks in the conductor are also clarified. By the fractofusion mechanism, the experimental facts that neutron emissions are observed in bursts, that sometimes they coincide with the deformation of a palladium specimen, and that in many experiments excess neutrons were not observed are qualitatively explained. The upper limit of the total fractofusion yields during the absorption of deuterium atoms by palladium specimens are estimated.

  18. Mechanical Engineering ME 3720 FLUID MECHANICS

    E-Print Network [OSTI]

    Panchagnula, Mahesh

    Mechanical Engineering ME 3720 FLUID MECHANICS Pre-requisite: ME 2330 Co-requisite: ME 3210) to develop an understanding of the physical mechanisms and the mathematical models of fluid mechanics of fluid mechanics problems in engineering practice. The basic principles of fluid mechanics

  19. Effect of non-diffusive processes on transport and its interpretation in the tokamak plasma edge

    SciTech Connect (OSTI)

    Stacey, Weston M. [Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)] [Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2013-11-15

    An interpretive methodology improved to account for two non-diffusive transport mechanisms—particle pinch and ion orbit loss—was applied to interpret the difference in transport (i) between a discharge with Resonance Magnetic Perturbations and a High confinement mode discharge with otherwise identical operating parameters and (ii) between the Low confinement and High confinement phases of a discharge free of Edge Localized Modes. Differences in particle and energy diffusion coefficients and in the particle pinch were inferred from the experimental data, and the inferred experiment thermal diffusion coefficients were compared with various theoretical predictions. The effect of taking ion orbit loss into account in the interpretation was quantified, and the possible relation of ion orbit loss to the observed transport “edge shortfall” is discussed.

  20. Facilitated diffusion framework for transcription factor search with conformational changes

    E-Print Network [OSTI]

    Jérôme Cartailler; Jürgen Reingruber

    2015-07-09

    Cellular responses often require the fast activation or repression of specific genes, which depends on Transcription Factors (TFs) that have to quickly find the promoters of these genes within a large genome. Transcription Factors (TFs) search for their DNA promoter target by alternating between bulk diffusion and sliding along the DNA, a mechanism known as facilitated diffusion. We study a facilitated diffusion framework with switching between three search modes: a bulk mode and two sliding modes triggered by conformational changes between two protein conformations. In one conformation (search mode) the TF interacts unspecifically with the DNA backbone resulting in fast sliding. In the other conformation (recognition mode) it interacts specifically and strongly with DNA base pairs leading to slow displacement. From the bulk, a TF associates with the DNA at a random position that is correlated with the previous dissociation point, which implicitly is a function of the DNA structure. The target affinity depends on the conformation. We derive exact expressions for the mean first passage time (MFPT) to bind to the promoter and the conditional probability to bind before detaching when arriving at the promoter site. We systematically explore the parameter space and compare various search scenarios. We compare our results with experimental data for the dimeric Lac repressor search in E.Coli bacteria. We find that a coiled DNA conformation is absolutely necessary for a fast MFPT. With frequent spontaneous conformational changes, a fast search time is achieved even when a TF becomes immobilized in the recognition state due to the specific bindings. We find a MFPT compatible with experimental data in presence of a specific TF-DNA interaction energy that has a Gaussian distribution with a large variance.

  1. FRONT SPEEDS IN THE VANISHING DIFFUSION LIMIT FOR REACTION-DIFFUSION-CONVECTION EQUATIONS

    E-Print Network [OSTI]

    Mascia, Corrado

    velocity. This convergence also yields a reaction- independent sufficient condition for the minimalFRONT SPEEDS IN THE VANISHING DIFFUSION LIMIT FOR REACTION-DIFFUSION-CONVECTION EQUATIONS E.C.M. CROOKS AND C. MASCIA Abstract. Travelling fronts for scalar balance laws with monostable reaction

  2. A pumping system for measuring coastal diffusion coefficients 

    E-Print Network [OSTI]

    Bolen, Zane Kevin

    1980-01-01

    system was used to measure surface horizontal diffusion coefficients in the vicin- ity of the diffuser. These experiments were also used to develop tech- niques of underway sampling as well as measuring site specific horizon- tal diffusion... coefficients. Measurement of horizontal diffusion coef- ficients used a continuous point source of tracer material to produce a plume that could be profiled using the pumping system connected to a fluorometer. The resultant horizontal diffusion coefficients...

  3. Field-Scale Effective Matrix Diffusion Coefficient for FracturedRock: Results From Literature Survey

    SciTech Connect (OSTI)

    Zhou, Quanlin; Liu, Hui Hai; Molz, Fred J.; Zhang, Yingqi; Bodvarsson, Gudmundur S.

    2005-03-28

    Matrix diffusion is an important mechanism for solutetransport in fractured rock. We recently conducted a literature survey onthe effective matrix diffusion coefficient, Dem, a key parameter fordescribing matrix diffusion processes at the field scale. Forty fieldtracer tests at 15 fractured geologic sites were surveyed and selectedfor study, based on data availability and quality. Field-scale Dem valueswere calculated, either directly using data reported in the literature orby reanalyzing the corresponding field tracer tests. Surveyed dataindicate that the effective-matrix-diffusion-coefficient factor FD(defined as the ratio of Dem to the lab-scale matrix diffusioncoefficient [Dem]of the same tracer) is generally larger than one,indicating that the effective matrix diffusion coefficient in the fieldis comparatively larger than the matrix diffusion coefficient at therock-core scale. This larger value could be attributed to the manymass-transfer processes at different scales in naturally heterogeneous,fractured rock systems. Furthermore, we observed a moderate trend towardsystematic increase in the emDFmDDF value with observation scale,indicating that the effective matrix diffusion coefficient is likely tobe statistically scale dependent. The FD value ranges from 1 to 10,000for observation scales from 5 to 2,000 m. At a given scale, the FD valuevaries by two orders of magnitude, reflecting the influence of differingdegrees of fractured rock heterogeneity at different sites. In addition,the surveyed data indicate that field-scale longitudinal dispersivitygenerally increases with observation scale, which is consistent withprevious studies. The scale-dependent field-scale matrix diffusioncoefficient (and dispersivity) may have significant implications forassessing long-term, large-scale radionuclide and contaminant transportevents in fractured rock, both for nuclear waste disposal and contaminantremediation.

  4. Soot precursor measurements in benzene and hexane diffusion flames

    SciTech Connect (OSTI)

    Kobayashi, Y.; Furuhata, T.; Amagai, K.; Arai, M.

    2008-08-15

    To clarify the mechanism of soot formation in diffusion flames of liquid fuels, measurements of soot and its precursors were carried out. Sooting diffusion flames formed by a small pool combustion equipment system were used for this purpose. Benzene and hexane were used as typical aromatic and paraffin fuels. A laser-induced fluorescence (LIF) method was used to obtain spatial distributions of polycyclic aromatic hydrocarbons (PAHs), which are considered as soot particles. Spatial distributions of soot in test flames were measured by a laser-induced incandescence (LII) method. Soot diameter was estimated from the temporal change of LII intensity. A region of transition from PAHs to soot was defined from the results of LIF and LII. Flame temperatures, PAH species, and soot diameters in this transition region were investigated for both benzene and hexane flames. The results show that though the flame structures of benzene and hexane were different, the temperature in the PAHs-soot transition region of the benzene flame was similar to that of the hexane flame. Furthermore, the relationship between the PAH concentrations measured by gas chromatography in both flames and the PAH distributions obtained from LIF are discussed. It was found that PAHs with smaller molecular mass, such as benzene and toluene, remained in both the PAHs-soot transition and sooting regions, and it is thought that molecules heavier than pyrene are the leading candidates for soot precursor formation. (author)

  5. A Comparison of Fick and Maxwell-Stefan Diffusion Formulations in PEMFC Cathode Gas Diffusion Layers

    E-Print Network [OSTI]

    Lindstrom, Michael

    2013-01-01

    This paper explores the mathematical formulations of Fick and Maxwell-Stefan diffusion in the context of polymer electrolyte membrane fuel cell cathode gas diffusion layers. Formulations of diffusion combined with mass-averaged Darcy flow are considered for three component gases. Fick formulations can be considered as approximations of Maxwell-Stefan in a certain sense. For this application, the formulations can be compared computationally in a simple, one dimensional setting. We observe that the predictions of the formulations are very similar, despite their seemingly different structure. Analytic insight is given to the result. In addition, it is seen that for both formulations, diffusion laws are small perturbations from bulk flow. The work is also intended as a reference to multi-component gas diffusion formulations in the fuel cell setting.

  6. Multiscale simulation of xenon diffusion and grain boundary segregation in UO?

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

    Andersson, David A.; Tonks, Michael R.; Casillas, Luis; Vyas, Shyam; Nerikar, Pankaj; Uberuaga, Blas P.; Stanek, Christopher R.

    2015-07-01

    In light water reactor fuel, gaseous fission products segregate to grain boundaries, resulting in the nucleation and growth of large intergranular fission gas bubbles. The segregation rate is controlled by diffusion of fission gas atoms through the grains and interaction with the boundaries. Based on the mechanisms established from earlier density functional theory (DFT) and empirical potential calculations, diffusion models for xenon (Xe), uranium (U) vacancies and U interstitials in UO? have been derived for both intrinsic (no irradiation) and irradiation conditions. Segregation of Xe to grain boundaries is described by combining the bulk diffusion model with a model formore »the interaction between Xe atoms and three different grain boundaries in UO? (?5 tilt, ?5 twist and a high angle random boundary), as derived from atomistic calculations. The present model does not attempt to capture nucleation or growth of fission gas bubbles at the grain boundaries. The point defect and Xe diffusion and segregation models are implemented in the MARMOT phase field code, which is used to calculate effective Xe and U diffusivities as well as to simulate Xe redistribution for a few simple microstructures.« less

  7. Effects of temporally varying liquid-phase mass diffusivity in multicomponent droplet gasification

    SciTech Connect (OSTI)

    Zhang, Huiqiang [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Department of Engineering Mechanics, Tsinghua University, Beijing, 100084 (China); Law, Chung K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

    2008-06-15

    The relative roles of liquid-phase diffusional resistance and volatility differential in multicomponent droplet gasification are revisited, recognizing that liquid-phase mass diffusivities can be substantially increased as the droplet is progressively heated upon initiation of gasification, leading to a corresponding substantial weakening of the diffusional resistance. Calculations performed using realistic and temperature-dependent thermal and mass diffusivities indeed substantiate this influence. In particular, the calculated results agree with the literature experimental data, indicating that the gasification mechanism of multicomponent fuels is intermediate between diffusion and distillation limits. Investigation was also performed on gasification at elevated pressures, recognizing that the liquid boiling point and hence the attainable droplet temperature would increase with increasing pressure, causing further weakening of the liquid-phase diffusional resistance. This possibility was again verified through calculated results, suggesting further departure from diffusion limit toward distillation limit behavior for gasification at high pressures. The study also found that diffusional resistance is stronger for the lighter, gasoline-like fuels as compared to the heavier, diesel-like fuels because the former have overall lower boiling points, lower attainable droplet temperatures, and hence lower mass diffusivities in spite of their lower molecular weights. (author)

  8. Topology, finite time Lyapunov exponents, and barriers for diffusive transport in advection-diffusion problems

    SciTech Connect (OSTI)

    Tang, Xianzhu [College of William and Mary, Williamsburg, VA (United States); Boozer, A.H. [Columbia Univ., New York, NY (United States)

    1996-12-31

    A wide range of transport problems are of advection-diffusion type. Typical fluid problems of this type are the relaxation of temperature differences in a room or the spread of a contaminant in a river. Important examples in plasma include the relaxation of electrons in a region of stochastic magnetic field lines and the evolution of the magnetic field embedded in a conducting fluid. The archetypal model equation is the advection-diffusion equation. The quantity being transported is {phi}. The flow velocity of the medium, v(x, t), is assumed given and independent of {phi}. The diffusive flux is {Tau}{sub d} = -D{del}{phi}. If the flow is chaotic, the properties of the transport are determined by the spatial and time dependence of the finite time Lyapunov exponent {lambda}({xi}, t). The rapid diffusive transport occurs only along the field line (s line) of the vector s, which defines the stable direction in which neighboring points asymptotically converge. The topology of the s lines affects the diffusive transport through the finite time Lyapunov exponent. We discover that the spatial variation of the finite time Lyapunov exponent along the s lines is smooth and determined by the topology of the s lines. For example, the finite time Lyapunov exponent reaches local minima if the s line makes a sharp bend. These topological bends hinder the diffusive transport and act as a barrier for diffusive relaxation. Such barriers for diffusion reside inside the chaotic region and they persist even the flow is highly chaotic. In the case of the electron relaxation in a region of stochastic field lines, there is a rapid diffusive relaxation of the spatial inhomogeneity in the electron distribution function which is typical of the chaotic transport of a passive scalar. But the diffusive relaxation of the pitch angle distribution is much slower.

  9. 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

  10. Reverse-selective diffusion in nanocomposite membranes

    E-Print Network [OSTI]

    Reghan J. Hill

    2005-10-27

    The permeability of certain polymer membranes with impenetrable nanoinclusions increases with the particle volume fraction (Merkel et al., Science, 296, 2002). This intriguing observation contradicts even qualitative expectations based on Maxwell's classical theory of conduction/diffusion in composites with homogeneous phases. This letter presents a simple theoretical interpretation based on classical models of diffusion and polymer physics. An essential feature of the theory is a polymer-segment depletion layer at the inclusion-polymer interface. The accompanying increase in free volume leads to a significant increase in the local penetrant diffusivity, which, in turn, increases the bulk permeability while exhibiting reverse selectivity. This model captures the observed dependence of the bulk permeability on the inclusion size and volume fraction, providing a straightforward connection between membrane microstructure and performance.

  11. Fission Enhanced diffusion of uranium in zirconia

    E-Print Network [OSTI]

    Bérerd, N; Moncoffre, N; Sainsot, P; Faust, H; Catalette, H

    2005-01-01

    This paper deals with the comparison between thermal and Fission Enhanced Diffusion (FED) of uranium into zirconia, representative of the inner face of cladding tubes. The experiments under irradiation are performed at the Institut Laue Langevin (ILL) in Grenoble using the Lohengrin spectrometer. A thin $^{235}UO\\_2$ layer in direct contact with an oxidized zirconium foil is irradiated in the ILL high flux reactor. The fission product flux is about 10$^{11}$ ions cm$^{-2}$ s$^{-1}$ and the target temperature is measured by an IR pyrometer. A model is proposed to deduce an apparent uranium diffusion coefficient in zirconia from the energy distribution broadening of two selected fission products. It is found to be equal to 10$^{-15}$ cm$^2$ s$^{-1}$ at 480$\\circ$C and compared to uranium thermal diffusion data in ZrO$\\_2$ in the same pressure and temperature conditions. The FED results are analysed in comparison with literature data.

  12. Maximal energy extraction under discrete diffusive exchange

    E-Print Network [OSTI]

    Michael J. Hay; Jeremy Schiff; Nathaniel J. Fisch

    2015-08-14

    Waves propagating through a bounded plasma can rearrange the densities of states in the six-dimensional velocity-configuration phase space. Depending on the rearrangement, the wave energy can either increase or decrease, with the difference taken up by the total plasma energy. In the case where the rearrangement is diffusive, only certain plasma states can be reached. It turns out that the set of reachable states through such diffusive rearrangements has been described in very different contexts. Building upon those descriptions, and making use of the fact that the plasma energy is a linear functional of the state densities, the maximal extractable energy under diffusive rearrangement can then be addressed through linear programming.

  13. Maximal energy extraction under discrete diffusive exchange

    E-Print Network [OSTI]

    Hay, Michael J; Fisch, Nathaniel J

    2015-01-01

    Waves propagating through a bounded plasma can rearrange the densities of states in the six-dimensional velocity-configuration phase space. Depending on the rearrangement, the wave energy can either increase or decrease, with the difference taken up by the total plasma energy. In the case where the rearrangement is diffusive, only certain plasma states can be reached. It turns out that the set of reachable states through such diffusive rearrangements has been described in very different contexts. Building upon those descriptions, and making use of the fact that the plasma energy is a linear functional of the state densities, the maximal extractable energy under diffusive rearrangement can then be addressed through linear programming.

  14. Derivation of effective fission gas diffusivities in UO2 from lower length scale simulations and implementation of fission gas diffusion models in BISON

    SciTech Connect (OSTI)

    Andersson, Anders David Ragnar; Pastore, Giovanni; Liu, Xiang-Yang; Perriot, Romain Thibault; Tonks, Michael; Stanek, Christopher Richard

    2014-11-07

    This report summarizes the development of new fission gas diffusion models from lower length scale simulations and assessment of these models in terms of annealing experiments and fission gas release simulations using the BISON fuel performance code. Based on the mechanisms established from density functional theory (DFT) and empirical potential calculations, continuum models for diffusion of xenon (Xe) in UO2 were derived for both intrinsic conditions and under irradiation. The importance of the large XeU3O cluster (a Xe atom in a uranium + oxygen vacancy trap site with two bound uranium vacancies) is emphasized, which is a consequence of its high mobility and stability. These models were implemented in the MARMOT phase field code, which is used to calculate effective Xe diffusivities for various irradiation conditions. The effective diffusivities were used in BISON to calculate fission gas release for a number of test cases. The results are assessed against experimental data and future directions for research are outlined based on the conclusions.

  15. Mechanical Buckling: Mechanics, Metrology, and Stretchable Electronics

    E-Print Network [OSTI]

    Rogers, John A.

    Mechanical Buckling: Mechanics, Metrology, and Stretchable Electronics By Dahl-Young Khang, John A of wrinkling is in aging human skin. All such phenomena originate from the same mechanism, i.e., mechanical of the wave, or their wavelength, depends upon the film thickness and/or mechanical properties of materials

  16. Self- and zinc diffusion in gallium antimonide

    SciTech Connect (OSTI)

    Nicols, Samuel Piers

    2002-03-26

    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.

  17. The heat and mass transfer phenomena in micro-scale for drug diffusion to brain tissue, the simulation of oxygen/drug diffusion in a three dimensional capillary network, and a reduced chemical kinetic modeling of gas

    E-Print Network [OSTI]

    modeling of gas turbine combustion for Jet propellant-10 have been studied numerically. For the numerical, a computational fluid dynamics (CFD) model has been developed to simulate the blood flow and oxygen/drug diffusion agreement. Finally, a chemical kinetic mechanism of gas turbine combustion for Jet Propellant-10 has been

  18. Molecular Modeling of Diffusion on a Crystalline PETN Surface

    SciTech Connect (OSTI)

    Lin, P; Khare, R; Gee, R H; Weeks, B L

    2007-07-13

    Surface diffusion on a PETN crystal was investigated by treating the surface diffusion as an activated process in the formalism of transition state theory. In particular, surface diffusion on the (110) and (101) facets, as well as diffusion between these facets, were considered. We successfully obtained the potential energy barriers required for PETN surface diffusion. Our results show that the (110) surface is more thermally active than the (101) surface and PETN molecules mainly diffuses from the (110) to (101) facet. These results are in good agreement with experimental observations and previous simulations.

  19. CARBON DIFFUSION ACROSS DISSIMILAR STEEL WELDS

    E-Print Network [OSTI]

    Cambridge, University of

    CARBON DIFFUSION ACROSS DISSIMILAR STEEL WELDS By Julia Margaret Race St. John's College, Cambridge. 111 #12;#12;ABSTRACT Dissimilar steel welds are used extensively in the power generation industry to the high alloy side of the weld. This leaves an area on one side of the weld denuded of carbon

  20. Diffusion Processes in Turbulent Magnetic Fields

    E-Print Network [OSTI]

    Alex Lazarian

    2007-07-05

    We study of the effect of turbulence on diffusion processes within magnetized medium. While we exemplify our treatment with heat transfer processes, our results are quite general and are applicable to different processes, e.g. diffusion of heavy elements. Our treatment is also applicable to describing the diffusion of cosmic rays arising from magnetic field wandering. In particular, we find that when the energy injection velocity is smaller than the Alfven speed the heat transfer is partially suppressed, while in the opposite regime the effects of turbulence depend on the intensity of driving. In fact, the scale $l_A$ at which the turbulent velocity is equal the Alfven velocity is a new important parameter. When the electron mean free path $\\lambda$ is larger than $l_A$, the stronger the the turbulence, the lower thermal conductivity by electrons is. The turbulent motions, however, induces their own advective transport, that can provide effective diffusivity. For clusters of galaxies, we find that the turbulence is the most important agent for heat transfer. We also show that the domain of applicability of the subdiffusion concept is rather limited.

  1. Particle Size Dependence of the Ionic Diffusivity

    E-Print Network [OSTI]

    Bazant, Martin Z.

    material for rechargeable lithium batteries, specifically explaining why it functions exclusively on the nanoscale. KEYWORDS Batteries, diffusion, nano, ab initio T he benefit of nanosizing materials on bulk for rechargeable Li+ ion batteries that only operates in batteries when in nanoform, though the results should

  2. APPARENT PULSE DIFFUSION DUE TO DISORDERED MICROSTRUCTURE

    E-Print Network [OSTI]

    Solna, Knut

    APPARENT PULSE DIFFUSION DUE TO DISORDERED MICROSTRUCTURE A. Nachbin \\Lambda and K. Sølna y \\Lambda, and it is important to describe when and how fine scale heterogeneities interact with a traveling seismic pulse. We are interested in pulse shaped waves that interact with the rapidly varying features (i.e. microstruture

  3. Magnetic flux diffusion through HTS shields

    E-Print Network [OSTI]

    Wong, Kai-Wai; Fan, C. X.; Havenhill, A. D.

    1998-06-01

    Slow field leakage in a polycrystalline superconducting cupshield placed in an external axial field (H-ext) much weaker than H-C1 shows a diffusive time dependence with a time scale of 10(2) s. As the field strength increases but is still less than...

  4. Forecasting Turbulent Modes with Nonparametric Diffusion Models

    E-Print Network [OSTI]

    Tyrus Berry; John Harlim

    2015-01-27

    This paper presents a nonparametric diffusion modeling approach for forecasting partially observed noisy turbulent modes. The proposed forecast model uses a basis of smooth functions (constructed with the diffusion maps algorithm) to represent probability densities, so that the forecast model becomes a linear map in this basis. We estimate this linear map by exploiting a previously established rigorous connection between the discrete time shift map and the semi-group solution associated to the backward Kolmogorov equation. In order to smooth the noisy data, we apply diffusion maps to a delay embedding of the noisy data, which also helps to account for the interactions between the observed and unobserved modes. We show that this delay embedding biases the geometry of the data in a way which extracts the most predictable component of the dynamics. The resulting model approximates the semigroup solutions of the generator of the underlying dynamics in the limit of large data and in the observation noise limit. We will show numerical examples on a wide-range of well-studied turbulent modes, including the Fourier modes of the energy conserving Truncated Burgers-Hopf (TBH) model, the Lorenz-96 model in weakly chaotic to fully turbulent regimes, and the barotropic modes of a quasi-geostrophic model with baroclinic instabilities. In these examples, forecasting skills of the nonparametric diffusion model are compared to a wide-range of stochastic parametric modeling approaches, which account for the nonlinear interactions between the observed and unobserved modes with white and colored noises.

  5. Reaction-diffusion approach in soft diffraction

    E-Print Network [OSTI]

    Rodion Kolevatov; Konstantin Boreskov

    2013-11-29

    We apply the reaction-diffusion (stochastic) approach to the numerical calculation of the elastic amplitude in the Reggeon Field Theory (RFT) and its single diffractive cut. Fits to the total, integrated and differential elastic cross sections with account of all Pomeron loops are reported together with all-loop calculation of the single difraction dissociation cross section.

  6. Diffusion in Flexible Pipes Susanne Brogaard Kristensen

    E-Print Network [OSTI]

    . . . . . . . . . . . . . . . . . . . . . 51 7.5.3 Carbon dioxide diffusion . . . . . . . . . . . . . . . . . 52 7.5.4 52Effect of C it may cause the outer sheath to burst. Also if large amounts of carbon dioxide, hydrogen sulfide . . . . . . . . . . . . . . . . . . . . . . . 39 1 . #12;7.3 Thermodynamic properties , . . . . . . . . . . . . . . . . . . . 45 7.4 First approach

  7. Cosmic ray penetration in diffuse clouds

    E-Print Network [OSTI]

    Morlino, G; Krause, J

    2015-01-01

    Cosmic rays are a fundamental source of ionization for molecular and diffuse clouds, influencing their chemical, thermal, and dynamical evolution. The amount of cosmic rays inside a cloud also determines the $\\gamma$-ray flux produced by hadronic collisions between cosmic rays and cloud material. We study the spectrum of cosmic rays inside and outside of a diffuse cloud, by solving the stationary transport equation for cosmic rays including diffusion, advection and energy losses due to ionization of neutral hydrogen atoms. We found that the cosmic ray spectrum inside a diffuse cloud differs from the one in the interstellar medium (ISM) for energies smaller than $E_{br}\\approx 100$ MeV, irrespective of the model details. Below $E_{br}$, the spectrum is harder (softer) than that in the ISM if the latter is a power law $\\propto p^{-s}$ with $s$ larger (smaller) than $\\sim0.42$. As a consequence also the ionization rate due to CRs is strongly affected. Assuming an average Galactic spectrum similar to the one infe...

  8. FIELD-SCALE EFFECTIVE MATRIX DIFFUSION COEFFICIENT FOR FRACTURED ROCK:RESULTS FROM LITERATURE SURVEY

    SciTech Connect (OSTI)

    Q. Zhou; Hui-Hai Liu; F.J. Molz; Y. Zhang; G.S. Bodvarsson

    2005-04-08

    Matrix diffusion is an important mechanism for solute transport in fractured rock. We recently conducted a literature survey on the effective matrix diffusion coefficient, D{sub m}{sup e}, a key parameter for describing matrix diffusion processes at the field scale. Forty field tracer tests at 15 fractured geologic sites were surveyed and selected for the study, based on data availability and quality. Field-scale D{sub m}{sup e} values were calculated, either directly using data reported in the literature or by reanalyzing the corresponding field tracer tests. Surveyed data indicate that the effective-matrix-diffusion-coefficient factor F{sub D} (defined as the ratio of D{sub m}{sup e} to the lab-scale matrix diffusion coefficient [D{sub m}] of the same tracer) is generally larger than one, indicating that the effective matrix diffusion coefficient in the field is comparatively larger than the matrix diffusion coefficient at the rock-core scale. This larger value can be attributed to the many mass-transfer processes at different scales in naturally heterogeneous, fractured rock systems. Furthermore, we observed a moderate trend toward systematic increase in the F{sub D} value with observation scale, indicating that the effective matrix diffusion coefficient is likely to be statistically scale dependent. The F{sub D} value ranges from 1 to 10,000 for observation scales from 5 to 2,000 m. At a given scale, the F{sub D} value varies by two orders of magnitude, reflecting the influence of differing degrees of fractured rock heterogeneity at different sites. In addition, the surveyed data indicate that field-scale longitudinal dispersivity generally increases with observation scale, which is consistent with previous studies. The scale-dependent field-scale matrix diffusion coefficient (and dispersivity) may have significant implications for assessing long-term, large-scale radionuclide and contaminant transport events in fractured rock, both for nuclear waste disposal and contaminant remediation.

  9. 728 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 The Electron Diffusion Coefficient in Energy

    E-Print Network [OSTI]

    Kaganovich, Igor

    Coefficient in Energy in Bounded Collisional Plasmas Lev D. Tsendin Abstract--The electron energies in typical, the momentum relaxation in collisions with neutrals is sig- nificantly faster than the energy relaxation due be de- scribed by a diffusion coefficient in energy . Both collisional and stochastic heating mechanisms

  10. Comparisons of diffusive and advective fluxes of gas phase volatile organic compounds (VOCs) in unsaturated zones under natural conditions

    E-Print Network [OSTI]

    Zhan, Hongbin

    is traditionally treated as the dominant mechanism of gas transport in unsaturated zones under natural conditionsComparisons of diffusive and advective fluxes of gas phase volatile organic compounds (VOCs) in unsaturated zones under natural conditions Kehua You a , Hongbin Zhan a,b, a Department of Geology

  11. Diffusion of barium atoms in the 6s5d 3 DJ metastable levels and the 6s2 1

    E-Print Network [OSTI]

    Huennekens, John

    ) for the barium-helium system are compared with values calculated from published, theoretical barium-helium to be negligible. Thus the main loss mechanism of 6s5d 3 DJ state atoms out of the detection region is diffusion

  12. MECHANICAL ENGINEERING Curriculum Notes

    E-Print Network [OSTI]

    Mohan, Chilukuri K.

    MECHANICAL ENGINEERING Curriculum Notes 2013-2014 1. Mechanical engineering students must complete of technical electives. 2. Technical electives must be taken within the Mechanical and Aerospace Engineering

  13. Physicalism versus quantum mechanics

    E-Print Network [OSTI]

    Stapp, Henry P; Theoretical Physics Group; Physics Division

    2009-01-01

    Foundations of Quantum Mechanics. (Princeton UniversityMind, Matter, and Quantum Mechanics, (Springer, Berlin & NewMindful Universe: Quantum Mechanics and the Participating

  14. Sandia Energy - Mechanical Testing

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

    Mechanical Testing Home Stationary Power Nuclear Fuel Cycle Advanced Nuclear Energy Nuclear Energy Systems Laboratory (NESL) Brayton Lab Mechanical Testing Mechanical...

  15. Solar Resonant Diffusion Waves as a Driver of Terrestrial Climate Change

    E-Print Network [OSTI]

    Robert Ehrlich

    2007-01-04

    A theory is described based on resonant thermal diffusion waves in the sun that appears to explain many details of the paleotemperature record for the last 5.3 million years. These include the observed periodicities, the relative strengths of each observed cycle, and the sudden emergence in time for the 100 thousand year cycle. Other prior work suggesting a link between terrestrial paleoclimate and solar luminosity variations has not provided any specific mechanism. The particular mechanism described here has been demonstrated empirically, although not previously invoked in the solar context. The theory also lacks most of the problems associated with Milankovitch cycles.

  16. BE 419 Principles of Continuum Mechanics and Dimitrije Stamenovi

    E-Print Network [OSTI]

    Vajda, Sandor

    , stress). Balance of energy (power theorem, 1st and 2nd laws of thermodynamics) 4. Constitutive equations: 1. Roberts, A. J. A One-Dimensional Introduction to Continuum Mechanics, World Scientific, Singapore of diffusion equation). Application: Slime mold aggregation. Balance of momentum (body forces, tractions

  17. Creep damage mechanisms in composites

    SciTech Connect (OSTI)

    Nutt, S.R.

    1994-10-17

    During the past year, research has focused on processing and characterization of intermetallic composites synthesized by plasma spray deposition. This versatile process allows rapid synthesis of a variety of different composite systems with potential applications for coatings, functionally gradient materials, rapid proto-typing and 3d printing, as well as near-net-shape processing of complex shapes. We have been pursuing an experimental program of research aimed at a fundamental understanding of the microstructural processes involved in the synthesis of intermetallic composites, including diffusion, heat transfer, grain boundary migration, and the dependence of these phenomena on deposition parameters. The work has been motivated by issues arising from composite materials manufacturing technologies. Recent progress is described in section B on the following topics: (1) Reactive atomization and deposition of intermetallic composites (Ni3Al); (2) Reactive synthesis of MoSi2-SiC composites; (3) Mechanical alloying of nanocrystalline alloys; (4) Tensile creep deformation of BMAS glass-ceramic composites.

  18. Self-Diffusion and Collective Diffusion of Charged colloids Studied by Dynamic Light Scattering

    E-Print Network [OSTI]

    Jacqueline Appell; Grégoire Porte; Eric Buhler

    2005-06-24

    A microemulsion of decane droplets stabilized by a non-ionic surfactant film is progressively charged by substitution of a non-ionic surfactant molecule by a cationic surfactant. We check that the microemulsion droplets remain identical within the explored range of volume fraction (0.02 to 0.18) and of the number of charge per droplets (0 to 40) . We probe the dynamics of these microemulsions by dynamic light scattering. Despite the similar structure of the uncharged and charged microemulsions the dynamics are very different . In the neutral microemulsion the fluctuations of polarization relax, as is well known, via the collective diffusion of the droplets. In the charged microemulsions, two modes of relaxation are observed. The fast one is ascribed classically to the collective diffusion of the charged droplets coupled to the diffusion of the counterions. The slow one has, to our knowledge, not been observed previously neither in similar microemulsions nor in charged spherical colloids. We show that the slow mode is also diffusive and suggest that its possible origine is the relaxation of local charge fluctuations via local exchange of droplets bearing different number of charges . The diffusion coefficient associated with this mode is then the self diffusion coefficient of the droplets.

  19. Fractionation of soil gases by diffusion of water vapor, gravitational settling, and thermal diffusion

    SciTech Connect (OSTI)

    Severinghaus, J.P.; Bender, M.L. [Univ. of Rhode Island, RI (United States)] [Univ. of Rhode Island, RI (United States); Keeling, R.F. [Scripps Institution of Oceanography, LaJolla, CA (United States)] [Scripps Institution of Oceanography, LaJolla, CA (United States); Broecker, W.S. [Lamont-Doherty Earth Observatory, Palisades, NY (United States)] [Lamont-Doherty Earth Observatory, Palisades, NY (United States)

    1996-03-01

    Air sampled from the moist unsaturated zone in a sand dune exhibits depletion in the heavy isotopes of N{sub 2} and O{sub 2}. We propose that the depletion is caused by a diffusive flux of water vapor out of the dune, which sweeps out the other gases, forcing them to diffuse back into the dune. The heavy isotopes of N{sub 2} and O{sub 2} diffuse back more slowly, resulting in a steady-state depletion of the heavy isotopesin the dune interior. We predict the effect`s magnitude with molecular diffusion theory and reproduce it in a laboratory simulation, finding good agreement between field, theory, and lab. The magnitude of the effect is governed by the ratio of the binary diffusivities against water vapor of a pair of gases, and increases {approximately} linearly with the difference between the water vapor mole fraction of the site and the advectively mixed reservoir with which it is in diffusive contact (in most cases the atmosphere). 32 refs., 1 fig., 3 tabs.

  20. Diapycnal advection by double diffusion and turbulence in the ocean

    E-Print Network [OSTI]

    St. Laurent, Louis C

    1999-01-01

    Observations of diapycnal mixing rates are examined and related to diapycnal advection for both double-diffusive and turbulent regimes. The role of double-diffusive mixing at the site of the North Atlantic Tracer Release ...

  1. Modelling of unidirectional thermal diffusers in shallow water

    E-Print Network [OSTI]

    Lee, Joseph Hun-Wei

    1977-01-01

    This study is an experimental and theoretical investigation of the temperature field and velocity field induced by a unidirectional thermal diffuser in shallow water. A multiport thermal diffuser is essentially a pipe laid ...

  2. The effects of double-diffusion on a baroclinic vortex

    E-Print Network [OSTI]

    Smith, Wendy Marie

    1987-01-01

    Laboratory experiments were performed to study the combined effects of double-diffusion and rotation on an oceanic intrusion. Intrusions are driven across density-compensated fronts by the divergence of the double-diffusive ...

  3. Role of carbon surface diffusion and strain on the epitaxial...

    Office of Scientific and Technical Information (OSTI)

    Role of carbon surface diffusion and strain on the epitaxial growth of graphene on SiC(0001). Citation Details In-Document Search Title: Role of carbon surface diffusion and strain...

  4. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Ductile failure in structural materials has been a problem the Temple Foundation Professorship in the Department of Aerospace Engineering and Engineering Mechanics, multiscale experimental mechanics, mechanics of polymers. He is a fellow of the American Society

  5. 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

  6. Research Review Mechanical Engineering

    E-Print Network [OSTI]

    Theune, Mariët

    Research Review Mechanical Engineering University of Twente #12;QANU / Research Review Mechanical;QANU / Research Review Mechanical Engineering / University of Twente 3 Report on the research assessment of Mechanical Engineering at the University of Twente Contents Preface

  7. Radiogenic Source Identification for the Helium Production-Diffusion ...

    E-Print Network [OSTI]

    2012-10-17

    Oct 18, 2012 ... Key words: Inverse source problem, production-diffusion equation, Tikhonov regularization. 1 Introduction. Helium isotopes are used ...

  8. Mechanisms of B cell Synapse Formation Predicted by Stochastic Simulation

    E-Print Network [OSTI]

    Philippos K. Tsourkas; Nicole Baumgarth; Scott I. Simon; Subhadip Raychaudhuri

    2006-10-19

    The clustering of B cell receptor (BCR) molecules and the formation of the protein segregation structure known as the immunological synapse appears to precede antigen (Ag) uptake by B cells. The mature B cell synapse is characterized by a central cluster of BCR/Ag molecular complexes surrounded by a ring of LFA-1/ICAM-1 complexes. Recent experimental evidence shows receptor clustering in B cells can occur via mechanical or signaling-driven processes. An alternative mechanism of diffusion and affinity-dependent binding has been proposed to explain synapse formation in the absence of signaling-driven processes. In this work, we investigated the biophysical mechanisms that drive immunological synapse formation in B cells across the physiological range of BCR affinity (KA~10^6-10^10 M-1) through computational modeling. Our computational approach is based on stochastic simulation of diffusion and reaction events with a clearly defined mapping between probabilistic parameters of our model and their physical equivalents. We show that a diffusion-and-binding mechanism is sufficient to drive synapse formation only at low BCR affinity and for a relatively stiff B cell membrane that undergoes little deformation. We thus predict the need for alternative mechanisms: a difference in the mechanical properties of BCR/Ag and LFA-1/ICAM-1 bonds and/or signaling driven processes.

  9. Diffusing acoustic wave spectroscopy M. L. Cowan,1

    E-Print Network [OSTI]

    Page, John

    Diffusing acoustic wave spectroscopy M. L. Cowan,1 I. P. Jones,1, * J. H. Page,1,2, and D. A. Weitz called diffusing acoustic wave spec- troscopy DAWS . In this technique, the motion of the scatterers e the particle velocity correlation function. Potential appli- cations of diffusing acoustic wave spectroscopy

  10. Proton Diffusion in Nickel Hydroxide Prediction of Active Material Utilization

    E-Print Network [OSTI]

    Weidner, John W.

    Proton Diffusion in Nickel Hydroxide Prediction of Active Material Utilization Sathya Motupally of the active material is controlled by the diffusion rate of protons through the film. This hypothesis- tion by including the effect of proton diffusion through the active material of the nickel electrode.6

  11. Transport approximations in partially diffusive media Guillaume Bal

    E-Print Network [OSTI]

    Bal, Guillaume

    Transport approximations in partially diffusive media Guillaume Bal Department of Applied Physics concerns the analysis of approximations of transport equations in diffusive media. Firstly, we consider a variational formulation for the first-order transport equation that has the correct diffusive behavior

  12. Technical Note Correction of Eddy-Current Distortions in Diffusion

    E-Print Network [OSTI]

    Technical Note Correction of Eddy-Current Distortions in Diffusion Tensor Images Using the Known,2 Purpose: To correct eddy-current artifacts in diffusion ten- sor (DT) images without the need to obtain- tortions caused by eddy currents induced by large diffusion gradients. We propose a new postacquisition

  13. Usage Policies Notebook for Thermco Atmospheric Diffusion Furnace system

    E-Print Network [OSTI]

    Mease, Kenneth D.

    Usage Policies Notebook for Thermco Atmospheric Diffusion Furnace system Revision date September 2014 #12;2 Emergency Plan for Diffusion Furnaces Standard Operating Procedures for Emergencies Contact;4 Usage Policies for Thermco Atmospheric Diffusion Furnace Standard policies for usage The Atmospheric

  14. Optoelectronic switches based on diffusive conduction Hilmi Volkan Demira

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    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 switching on a picosecond time scale . We present the characteristic Green's function of the diffusive

  15. A model for the diffuse attenuation coefficient of downwelling irradiance

    E-Print Network [OSTI]

    Lee, Zhongping

    A model for the diffuse attenuation coefficient of downwelling irradiance Zhong-Ping Lee1 Naval] The diffuse attenuation coefficient for downwelling irradiance (Kd) is an important parameter for ocean of downwelling irradiance, J. Geophys. Res., 110, C02016, doi:10.1029/2004JC002275. 1. Introduction [2] Diffuse

  16. Repeated interaction model for diffusion-induced Ramsey narrowing

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    Repeated interaction model for diffusion-induced Ramsey narrowing Yanhong Xiao 1, Irina Novikova 2. Xiao et al., Phys. Rev. Lett. 96, 043601 (2006)] we characterized diffusion-induced Ramsey narrowing presentation of the repeated interaction model of diffusion-induced Ramsey narrowing, with particular focus

  17. A Diffusion Model in Population Genetics with Mutation and Dynamic

    E-Print Network [OSTI]

    O'Leary, Michael

    A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness Mike O'Leary Department of Mathematics Towson University May 24, 2008 Mike O'Leary (Towson University) A Diffusion Model in Genetics May Miller, Georgetown University Mike O'Leary (Towson University) A Diffusion Model in Genetics May 24, 2008

  18. Chapter 1 Introduction 1.1 Why Diffusion in Polymers

    E-Print Network [OSTI]

    Goddard III, William A.

    I - 1 Chapter 1 Introduction 1.1 Why Diffusion in Polymers Various industrial applications of polymers involve diffusion of gases through polymersi . Membrane separation of gases in the gas and oil involve impeding the diffusion of gases through thin polymer films, commonly used as packaging food

  19. Variational principle for general diffusion problems June 28, 2004

    E-Print Network [OSTI]

    Tudorascu, Adrian

    -homogeneous nonlinear diffusion problems (of Fokker-Planck type) with time dependent coefficients. This work greatly with time-interpolants of minimizers arising from Wasserstein-type implicit schemes ([1], [11], [13], [14]: diffusion in plasmas, surface growth and transport of fluid in porous media, relative diffusion in turbulent

  20. Intermittency in Turbulent Diffusion Models with a Mean Gradient

    E-Print Network [OSTI]

    Majda, Andrew J.

    Intermittency in Turbulent Diffusion Models with a Mean Gradient Andrew J Majda and Xin T TongE30, 62G32 Submitted to: Nonlinearity 1. Introduction Turbulent diffusion is the transportation and diffusion. Its application ranges from the spread of hazardous plumes and mixing properties of turbulent

  1. DETAILED CHEMISTRY MODELING OF LAMINAR DIFFUSION FLAMES ON PARALLEL COMPUTERS

    E-Print Network [OSTI]

    . The gas­jet diffusion flame is the basic element of many combustion systems, such as gas turbines, ram­speed, three­dimensional, turbulent reacting systems, gas­jet laminar diffusion flames constitute a problem jets, and industrial furnaces. Furthermore, the fundamental understand­ ing of laminar diffusion flames

  2. Biosensor as a Reaction-Diffusion System

    E-Print Network [OSTI]

    Ghosh, Surya K; Sain, Anirban

    2012-01-01

    We model a biosensor as a reaction-diffusion process in a confined geometry. When a solution containing unknown concentration of antigens are injected into the closed chamber of the sensor, the antigens diffuse and react with a functionalised surface. These surface reactions are then converted to an optical signal, the intensity of which indicates the level of antigen content in the solution. We probe the spatio-temporal behavior of the system by studying the governing equations, using mean field approximation and numerical integration. Mean field analysis gives important insights about the dynamics, but in order to compare with real experiments and extract the values of the relevant kinetic parameters, numerical integration was necessary. We track down the operating conditions for quick and efficient response of the sensor.

  3. Reaction Diffusion patterns in Pseudoplatystoma fishes

    E-Print Network [OSTI]

    Aldo Ledesma-Durán; Héctor Juárez-Valencia; Iván Santamaría-Holek

    2016-01-05

    This paper studies how patterns derived from a system of reaction-diffusion equations may vary significantly depending upon boundary and initial conditions, as well as in the spatial dependence of the coefficients involved. From an extensive numerical study of the BVAM model, we demonstrate that the geometric pattern of a reaction-diffusion system is not uniquely determined by the value of the parameters in the equation. From this result, we suggest that the variability of patterns among individuals of the same species may have its roots in this sensitivity. Furthermore, this study analyzes briefly how the inclusion of the advection and the space dependency in the parameters of the model influences the forms of a specific pattern. The results of this study are compared to the skin patterns that appear in Pseudoplatystom} fishes.

  4. Diffusion barriers in modified air brazes

    DOE Patents [OSTI]

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

    2010-04-06

    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.

  5. Memory effects and active Brownian diffusion

    E-Print Network [OSTI]

    Ghosh, Pulak K; Marchegiani, Giampiero; Marchesoni, Fabio

    2015-01-01

    A self-propelled artificial microswimmer is often modeled as a ballistic Brownian particle moving with constant speed aligned along one of its axis, but changing direction due to random collisions with the environment. Similarly to thermal noise, its angular randomization is described as a memoryless stochastic process. Here, we speculate that finite-time correlations in the orientational dynamics can affect the swimmer's diffusivity. To this purpose we propose and solve two alternative models. In the first one we simply assume that the environmental fluctuations governing the swimmer's propulsion are exponentially correlated in time, whereas in the second one we account for possible damped fluctuations of the propulsion velocity around the swimmer's axis. The corresponding swimmer's diffusion constants are predicted to get, respectively, enhanced or suppressed upon increasing the model memory time. Possible consequences of this effect on the interpretation of the experimental data are discussed.

  6. Memory effects and active Brownian diffusion

    E-Print Network [OSTI]

    Pulak K. Ghosh; Yunyun Li; Giampiero Marchegiani; Fabio Marchesoni

    2015-11-19

    A self-propelled artificial microswimmer is often modeled as a ballistic Brownian particle moving with constant speed aligned along one of its axis, but changing direction due to random collisions with the environment. Similarly to thermal noise, its angular randomization is described as a memoryless stochastic process. Here, we speculate that finite-time correlations in the orientational dynamics can affect the swimmer's diffusivity. To this purpose we propose and solve two alternative models. In the first one we simply assume that the environmental fluctuations governing the swimmer's propulsion are exponentially correlated in time, whereas in the second one we account for possible damped fluctuations of the propulsion velocity around the swimmer's axis. The corresponding swimmer's diffusion constants are predicted to get, respectively, enhanced or suppressed upon increasing the model memory time. Possible consequences of this effect on the interpretation of the experimental data are discussed.

  7. Methodology and apparatus for diffuse photon mimaging

    DOE Patents [OSTI]

    Feng, Shechao C. (Los Angeles, CA); Zeng, Fanan (Los Angeles, CA); Zhao, Hui-Lin (Los Angeles, CA)

    1997-12-09

    Non-invasive near infrared optical medical imaging devices for both hematoma detection in the brain and early tumor detection in the breast is achieved using image reconstruction which allows a mapping of the position dependent contrast diffusive propagation constants, which are related to the optical absorption coefficient and scattering coefficient in the tissue, at near infrared wavelengths. Spatial resolutions in the range of 5 mm for adult brain sizes and breast sizes can be achieved. The image reconstruction utilizes WKB approximation on most probable diffusion paths which has as lowest order approximation the straight line-of-sight between the plurality of sources and the plurality of detectors. The WKB approximation yields a set of linear equations in which the contrast optical absorption coefficients are the unknowns and for which signals can be generated to produce a pixel map of the contrast optical resolution of the scanned tissue.

  8. Methodology and apparatus for diffuse photon imaging

    DOE Patents [OSTI]

    Feng, S.C.; Zeng, F.; Zhao, H.L.

    1997-12-09

    Non-invasive near infrared optical medical imaging devices for both hematoma detection in the brain and early tumor detection in the breast is achieved using image reconstruction which allows a mapping of the position dependent contrast diffusive propagation constants, which are related to the optical absorption coefficient and scattering coefficient in the tissue, at near infrared wavelengths. Spatial resolutions in the range of 5 mm for adult brain sizes and breast sizes can be achieved. The image reconstruction utilizes WKB approximation on most probable diffusion paths which has as lowest order approximation the straight line-of-sight between the plurality of sources and the plurality of detectors. The WKB approximation yields a set of linear equations in which the contrast optical absorption coefficients are the unknowns and for which signals can be generated to produce a pixel map of the contrast optical resolution of the scanned tissue. 58 figs.

  9. Diffusion barriers in modified air brazes

    DOE Patents [OSTI]

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

    2013-04-23

    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.

  10. Diffuse-dynamic multiparameter diffractometry: A review

    SciTech Connect (OSTI)

    Molodkin, V. B. Shpak, A. P.; Kovalchuk, M. V.; Nosik, V. L.; Machulin, V. F.

    2010-12-15

    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.

  11. Glass Membrane For Controlled Diffusion Of Gases

    DOE Patents [OSTI]

    Shelby, James E. (Alfred Station, NY); Kenyon, Brian E. (Pittsburgh, PA)

    2001-05-15

    A glass structure for controlled permeability of gases includes a glass vessel. The glass vessel has walls and a hollow center for receiving a gas. The glass vessel contains a metal oxide dopant formed with at least one metal selected from the group consisting of transition metals and rare earth metals for controlling diffusion of the gas through the walls of the glass vessel. The vessel releases the gas through its walls upon exposure to a radiation source.

  12. Multicomponent Gas Diffusion in Porous Electrodes

    E-Print Network [OSTI]

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

    2014-01-01

    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...

  13. Transport and diffusion in the embedding map

    E-Print Network [OSTI]

    N. Nirmal Thyagu; Neelima Gupte

    2009-05-20

    We study the transport properties of passive inertial particles in a $2-d$ incompressible flows. Here the particle dynamics is represented by the $4-d$ dissipative embedding map of $2-d$ area-preserving standard map which models the incompressible flow. The system is a model for impurity dynamics in a fluid and is characterized by two parameters, the inertia parameter $\\alpha$, and the dissipation parameter $\\gamma$. We obtain the statistical characterisers of transport for this system in these dynamical regimes. These are, the recurrence time statistics, the diffusion constant, and the distribution of jump lengths. The recurrence time distribution shows a power law tail in the dynamical regimes where there is preferential concentration of particles in sticky regions of the phase space, and an exponential decay in mixing regimes. The diffusion constant shows behaviour of three types - normal, subdiffusive and superdiffusive, depending on the parameter regimes. Phase diagrams of the system are constructed to differentiate different types of diffusion behaviour, as well as the behaviour of the absolute drift. We correlate the dynamical regimes seen for the system at different parameter values with the transport properties observed at these regimes, and in the behaviour of the transients. This system also shows the existence of a crisis and unstable dimension variability at certain parameter values. The signature of the unstable dimension variability is seen in the statistical characterisers of transport. We discuss the implications of our results for realistic systems.

  14. Detector dependency of diffusive quantum monitorings

    E-Print Network [OSTI]

    Shakib Daryanoosh; Howard M. Wiseman; Jay M. Gambetta

    2015-05-01

    Continuous measurements play a pivotal role in the study of dynamical open quantum systems. `Dyne' detections are among the most widespread and efficient measurement schemes, and give rise to quantum diffusion of the conditioned state. In this work we study under what conditions the detector dependency of the conditional state of a quantum system subject to diffusive monitoring can be demonstrated experimentally, in the sense of ruling our any detector-independent pure-state dynamical model for the system. We consider an arbitrary number L of environments to which the system is coupled, and an arbitrary number K of different types of dyne detections. We prove that non-trivial necessary conditions for such a demonstration can be determined efficiently by semi-definite programming. To determine sufficient conditions, different physical environmental couplings and Hamiltonians for a qubit, and different sets of diffusive monitorings are scrutinized. We compare the threshold efficiencies that are sufficient in the various cases, as well as cases previously considered in the literature, to suggest the most feasible experimental options.

  15. Diffusion Processes Satisfying a Conservation Law Constraint

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

    Bakosi, J.; Ristorcelli, J. R.

    2014-03-04

    We investigate coupled stochastic differential equations governing N non-negative continuous random variables that satisfy a conservation principle. In various fields a conservation law requires that a set of fluctuating variables be non-negative and (if appropriately normalized) sum to one. As a result, any stochastic differential equation model to be realizable must not produce events outside of the allowed sample space. We develop a set of constraints on the drift and diffusion terms of such stochastic models to ensure that both the non-negativity and the unit-sum conservation law constraint are satisfied as the variables evolve in time. We investigate the consequencesmore »of the developed constraints on the Fokker-Planck equation, the associated system of stochastic differential equations, and the evolution equations of the first four moments of the probability density function. We show that random variables, satisfying a conservation law constraint, represented by stochastic diffusion processes, must have diffusion terms that are coupled and nonlinear. The set of constraints developed enables the development of statistical representations of fluctuating variables satisfying a conservation law. We exemplify the results with the bivariate beta process and the multivariate Wright-Fisher, Dirichlet, and Lochner’s generalized Dirichlet processes.« less

  16. Diffuse ?-ray emission from galactic pulsars

    SciTech Connect (OSTI)

    Calore, F. [GRAPPA Institute, University of Amsterdam, Science Park 904, 1090 GL Amsterdam (Netherlands); Di Mauro, M.; Donato, F., E-mail: f.calore@uva.nl, E-mail: mattia.dimauro@to.infn.it, E-mail: donato@to.infn.it [Dipartimento di Fisica, Torino University and INFN, Sezione di Torino, Via P. Giuria 1, I-10125 Torino (Italy)

    2014-11-20

    Millisecond pulsars (MSPs) are old fast-spinning neutron stars that represent the second most abundant source population discovered by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi). As guaranteed ?-ray emitters, they might contribute non-negligibly to the diffuse emission measured at high latitudes by Fermi-LAT (i.e., the Isotropic Diffuse ?-Ray Background (IDGRB)), which is believed to arise from the superposition of several components of galactic and extragalactic origin. Additionally, ?-ray sources also contribute to the anisotropy of the IDGRB measured on small scales by Fermi-LAT. In this manuscript we aim to assess the contribution of the unresolved counterpart of the detected MSPs population to the IDGRB and the maximal fraction of the measured anisotropy produced by this source class. To this end, we model the MSPs' spatial distribution in the Galaxy and the ?-ray emission parameters by considering observational constraints coming from the Australia Telescope National Facility pulsar catalog and the Second Fermi-LAT Catalog of ?-ray pulsars. By simulating a large number of MSP populations through a Monte Carlo simulation, we compute the average diffuse emission and the anisotropy 1? upper limit. We find that the emission from unresolved MSPs at 2 GeV, where the peak of the spectrum is located, is at most 0.9% of the measured IDGRB above 10° in latitude. The 1? upper limit on the angular power for unresolved MSP sources turns out to be about a factor of 60 smaller than Fermi-LAT measurements above 30°. Our results indicate that this galactic source class represents a negligible contributor to the high-latitude ?-ray sky and confirm that most of the intensity and geometrical properties of the measured diffuse emission are imputable to other extragalactic source classes (e.g., blazars, misaligned active galactic nuclei, or star-forming galaxies). Nevertheless, because MSPs are more concentrated toward the galactic center, we expect them to contribute significantly to the ?-ray diffuse emission at low latitudes. Because, along the galactic disk, the population of young pulsars overcomes in number that of MSPs, we compute the ?-ray emission from the whole population of unresolved pulsars, both young and millisecond, in two low-latitude regions: the inner Galaxy and the galactic center.

  17. Systematic variations in argon diffusion in feldspars: Constraints on diffusion lengthscales, diffusive anisotropy, and non-linear Arrhenius arrays and implications for noble gas thermochronometry

    E-Print Network [OSTI]

    Cassata, William

    2012-01-01

    pluton from 40 Ar/ 39 Ar geochronology and thermal modeling.for 40 Ar/ 39 Ar geochronology of naturally deformed rocks.1995. Multipath diffusion in geochronology. Contributions to

  18. Unsteady behavior of locally strained diffusion flames affected by curvature and preferential diffusion

    SciTech Connect (OSTI)

    Yoshida, Kenji; Takagi, Toshimi

    1999-07-01

    Experimental and numerical studies are made of transient H{sub 2}/N{sub 2}--air counterflow diffusion flames unsteadily strained by an impinging micro jet. Two-dimensional temperature measurements by laser Rayleigh scattering method and numerical computations taking into account detailed chemical kinetics are conducted paying attention to transient local extinction and reignition in relation to the unsteadiness, flame curvature and preferential diffusion effects. The results are as follows. (1) Transient local flame extinction is observed where the micro jet impinges. But, the transient flame can survive instantaneously in spite of quite high stretch rate where the steady flame cannot exist. (2) Reignition is observed after the local extinction due to the micro air jet impingement. The temperature after reignition becomes significantly higher than that of the original flame. This high temperature is induced by the concentration of H{sub 2} species due to the preferential diffusion in relation to the concave curvature. The predicted behaviors of the local transient extinction and reignition are well confirmed by the experiments. (3) The reignition is induced after the formation of combustible premixed gas mixture and the consequent flame propagation. (4) The reignition is hardly observed after the extinction by micro fuel jet impingement. This is due to the dilution of H{sub 2} species induced by the preferential diffusion in relation to the convex curvature. (5) The maximum flame temperature cannot be rationalized by the stretch rate but changes widely depending on the unsteadiness and the flame curvature in relation with preferential diffusion.

  19. Opto-mechanical Design of the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS)

    E-Print Network [OSTI]

    diffuse emissions from cooling million degree plasma. Details of local bubble thermal pressure, spatial adopted to meet the throughput, signal to noise, and spectral resolution requirements within the mass BENCH PICKOFF MIRRORS NORTH TOWER SLIT MECHANISMS SOUTH TOWER SLIT MECHANISMS DETECTOR VACUUM CHAMBER

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

    DOE Patents [OSTI]

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

    2009-12-15

    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.

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

    DOE Patents [OSTI]

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

    2008-02-12

    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.

  2. Method and apparatus for maintaining condensable constituents of a gas in a vapor phase during sample transport

    DOE Patents [OSTI]

    Felix, Larry Gordon; Farthing, William Earl; Irvin, James Hodges; Snyder, Todd Robert

    2010-05-18

    A system for fluid transport at elevated temperatures having a conduit having a fluid inlet end and a fluid outlet end and at least one heating element disposed within the conduit providing direct heating of a fluid flowing through the conduit. The system is particularly suited for preventing condensable constituents of a high temperature fluid from condensing out of the fluid prior to analysis of the fluid. In addition, operation of the system so as to prevent the condensable constituents from condensing out of the fluid surprisingly does not alter the composition of the fluid.

  3. Thin Film Deposition of Conducting Polymers and Carbon Allotropes via Interfacial Solution Processing and Evaporative Vapor Phase Polymerization

    E-Print Network [OSTI]

    D'Arcy, Julio Marcelo

    2012-01-01

    temperature and soda lime glass possesses the greatestNumber of peels (55 o C) Soda lime glass Borosilicate glasswas investigated using soda lime glass (i.e. a microscope

  4. Thin Film Deposition of Conducting Polymers and Carbon Allotropes via Interfacial Solution Processing and Evaporative Vapor Phase Polymerization

    E-Print Network [OSTI]

    D'Arcy, Julio Marcelo

    2012-01-01

    changes the wetting properties of a plastic from hydrophobicchloride plastic slides. c. The optoelectronic properties ofchloride plastic slides. c. The optoelectronic properties of

  5. Apparatus and method for maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling

    DOE Patents [OSTI]

    Felix, Larry Gordon; Farthing, William Earl; Irvin, James Hodges; Snyder, Todd Robert

    2010-05-11

    A dilution apparatus for diluting a gas sample. The apparatus includes a sample gas conduit having a sample gas inlet end and a diluted sample gas outlet end, and a sample gas flow restricting orifice disposed proximate the sample gas inlet end connected with the sample gas conduit and providing fluid communication between the exterior and the interior of the sample gas conduit. A diluted sample gas conduit is provided within the sample gas conduit having a mixing end with a mixing space inlet opening disposed proximate the sample gas inlet end, thereby forming an annular space between the sample gas conduit and the diluted sample gas conduit. The mixing end of the diluted sample gas conduit is disposed at a distance from the sample gas flow restricting orifice. A dilution gas source connected with the sample gas inlet end of the sample gas conduit is provided for introducing a dilution gas into the annular space, and a filter is provided for filtering the sample gas. The apparatus is particularly suited for diluting heated sample gases containing one or more condensable components.

  6. ZnO quantum dots synthesized by a vapor phase transport process J. G. Lu, Z. Z. Ye,a

    E-Print Network [OSTI]

    Wang, Zhong L.

    fabrication of ZnO QDs was conducted in a hori- zontal tube furnace. The system is shown in Fig. 1. Zinc the water of crystal- lization. Si 111 wafers were used as the substrates. The furnace temperature was set of the furnace, and the temperature gradient at the location between the center and the end of the furnace

  7. Chemically sensitive polymer-mediated nanoporous alumina SAW sensors for the detection of vapor-phase analytes 

    E-Print Network [OSTI]

    Perez, Gregory Paul

    2005-08-29

    We have investigated the chemical sensitivity of nanoporous (NP) alumina-coated surface acoustic wave (SAW) devices that have been surface-modified with polymeric mediating films. The research in this dissertation covers the refinement of the NP...

  8. Thin Film Deposition of Conducting Polymers and Carbon Allotropes via Interfacial Solution Processing and Evaporative Vapor Phase Polymerization

    E-Print Network [OSTI]

    D'Arcy, Julio Marcelo

    2012-01-01

    K. ; Shimidzu, T. Thin Solid Films 1989, 179, Matharu, Z. ;V. ; Malhotra, B. D. Thin Solid Films 2011, 519, 1110- (27)H. ; Rubner, M. F. Thin Solid Films 1994, 244, 990-994. (28)

  9. Thin Film Deposition of Conducting Polymers and Carbon Allotropes via Interfacial Solution Processing and Evaporative Vapor Phase Polymerization

    E-Print Network [OSTI]

    D'Arcy, Julio Marcelo

    2012-01-01

    produced by mixing water, a heavy oil, and a dye. a. Tiltedproduced by mixing water, a heavy oil, and a dye. a. Tiltednanofibers, water and a heavy oil such as chloroform or

  10. Thin Film Deposition of Conducting Polymers and Carbon Allotropes via Interfacial Solution Processing and Evaporative Vapor Phase Polymerization

    E-Print Network [OSTI]

    D'Arcy, Julio Marcelo

    2012-01-01

    that house three cartridge heaters and a thermocouple. d.that house three cartridge heaters and a thermocouple. d.the CVD chamber. A cartridge heater and a thermocouple are

  11. Thin Film Deposition of Conducting Polymers and Carbon Allotropes via Interfacial Solution Processing and Evaporative Vapor Phase Polymerization

    E-Print Network [OSTI]

    D'Arcy, Julio Marcelo

    2012-01-01

    adsorption, 19 drop-casting, 20,21 grafting, 22 slide-5 such as spin-coating, 6 dip-coating, drop-casting, 11 andtilt- drop casting. 7 These techniques, however, suffer from

  12. Thin Film Deposition of Conducting Polymers and Carbon Allotropes via Interfacial Solution Processing and Evaporative Vapor Phase Polymerization

    E-Print Network [OSTI]

    D'Arcy, Julio Marcelo

    2012-01-01

    produced by mixing water, a heavy oil, and a dye. a. Tiltednanofibers, water and a heavy oil such as chloroform orproduced by mixing water, a heavy oil, and a dye. a. Tilted

  13. Oxygen diffusion of anodic surface oxide film on titanium studied by Auger electron spectroscopy. [Oxygen diffusivity

    SciTech Connect (OSTI)

    Wang, P.S.; Wittberg, T.N.; Keil, R.G.

    1982-01-01

    TiO/sub 2/ films of about 1000 A were grown onto titanium foils anodically under galvanostatic conditions at 20 mA/cm/sup 2/ in saturated aqueous solutions of ammonium tetraborate. The samples were then aged at 450, 500, and 550/sup 0/C, and oxygen diffusion was observed by Auger electron spectroscopy (AES) profilings. The oxygen diffusivities were calculated by Fick's Second Law, using the Boltzmann-Matano solution, to be 9.4 x 10/sup -17/, 2.6 x 10/sup -16/, and 1.2 x 10/sup -15/ cm/sup 2//sec at 450, 500, and 550/sup 0/C, respectively. The diffusivities obtained by this method were also compared with those obtained using an exact solution to Fick's Second Law. The activation energy was calculated to be 30 kcal/mole.

  14. Mechanical & Biomedical Engineering

    E-Print Network [OSTI]

    Barrash, Warren

    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

  15. Mechanical Engineering & Thermal Group

    E-Print Network [OSTI]

    Mojzsis, Stephen J.

    LASP's mechanical analysts also lead mechanical verification testing including: random vibration, forceMechanical 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

  16. Solar mechanics thermal response capabilities.

    SciTech Connect (OSTI)

    Dobranich, Dean D.

    2009-07-01

    In many applications, the thermal response of structures exposed to solar heat loads is of interest. Solar mechanics governing equations were developed and integrated with the Calore thermal response code via user subroutines to provide this computational simulation capability. Solar heat loads are estimated based on the latitude and day of the year. Vector algebra is used to determine the solar loading on each face of a finite element model based on its orientation relative to the sun as the earth rotates. Atmospheric attenuation is accounted for as the optical path length varies from sunrise to sunset. Both direct and diffuse components of solar flux are calculated. In addition, shadowing of structures by other structures can be accounted for. User subroutines were also developed to provide convective and radiative boundary conditions for the diurnal variations in air temperature and effective sky temperature. These temperature boundary conditions are based on available local weather data and depend on latitude and day of the year, consistent with the solar mechanics formulation. These user subroutines, coupled with the Calore three-dimensional thermal response code, provide a complete package for addressing complex thermal problems involving solar heating. The governing equations are documented in sufficient detail to facilitate implementation into other heat transfer codes. Suggestions for improvements to the approach are offered.

  17. L\\'evy Fluctuations and Tracer Diffusion in Dilute Suspensions of Algae and Bacteria

    E-Print Network [OSTI]

    Zaid, Irwin M; Yeomans, Julia M

    2010-01-01

    Swimming microorganisms rely on effective mixing strategies to achieve efficient nutrient influx. Recent experiments, probing the mixing capability of unicellular biflagellates, revealed that passive tracer particles exhibit anomalous non-Gaussian diffusion when immersed in a dilute suspension of self-motile Chlamydomonas reinhardtii algae. Qualitatively, this observation can be explained by the fact that the algae induce a fluid flow that may occasionally accelerate the colloidal tracers to relatively large velocities. A satisfactory quantitative theory of enhanced mixing in dilute active suspensions, however, is lacking at present. In particular, it is unclear how non-Gaussian signatures in the tracers' position distribution are linked to the self-propulsion mechanism of a microorganism. Here, we develop a systematic theoretical description of anomalous tracer diffusion in active suspensions, based on a simplified tracer-swimmer interaction model that captures the typical distance scaling of a microswimmer'...

  18. Diffusion injected multi-quantum well light-emitting diode structure

    SciTech Connect (OSTI)

    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)

    2014-02-24

    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.

  19. On-line vibration and analysis system at the Paducah Gaseous Diffusion Plant

    SciTech Connect (OSTI)

    Herricks, D.M.; Strunk, W.D.

    1988-02-01

    The enrichment facility in Paducah, KY uses a unique hard-wired vibration monitoring and analysis system for gaseous diffusion equipment. The axial flow and centrifugal flow compressors used in uranium enrichment range in size from 6 feet in diameter to less than one foot in diameter. These compressors must operate smoothly and safely, without breech of containment, since the working fluid of gaseous diffusion is gaseous UF/sub 6/. The condition of 1925 compressors is monitored by use of the 2500 point vibration analysis system. Since the failure mechanisms of the compressors are well known and documented, only one accelerometer per machine is needed for most machines. The system is completely automated and can generate spectra or broadband levels in either acceleration or velocity units. Levels are stored for historical review. The analyst can, via a custom telecommunications link, view and analyze data from all monitored points with an office PC. 4 figs.

  20. O and H diffusion in uraninite: Implications for fluid-uraninite interactions, nuclear waste disposal, and nuclear forensics

    SciTech Connect (OSTI)

    Fayek, Mostafa [University of Manitoba, Canada; Anovitz, Lawrence {Larry} M [ORNL; Cole, David [Ohio State University; Bostick, Debra A [ORNL

    2011-01-01

    Diffusion coefficients for oxygen and hydrogen were determined from a series of natural uraninite H2O experiments between 50 and 700 C. Under hydrous conditions there are two diffusion mechanisms: (1) an initial extremely fast-path diffusion mechanism that overprinted the oxygen isotopic composition of the entire crystals regardless of temperature and (2) a slower volume-diffusive mechanism dominated by defect clusters that displace or eject nearest neighbor oxygen atoms to form two interstitial sites and two partial vacancies, and by vacancy migration. Using the volume diffusion coefficients in the temperature range of 400 600 C, diffusion coefficients for oxygen can be represented by D = 1.90e5 exp (123,382 J/RT) cm2/s and for temperatures between 100 and 300 C the diffusion coefficients can be represented by D = 1.95e10 exp (62484 J/ RT) cm2/s, where the activation energies for uraninite are 123.4 and 62.5 kJ/mol, respectively. Hydrogen diffusion in uraninite appears to be controlled by similar mechanisms as oxygen. Using the volume diffusion coefficients for temperatures between 50 and 700 C, diffusion coefficients for hydrogen can be represented by D = 9.28e6 exp (156,528 J/RT) cm2/s for temperatures between 450 and 700 C and D = 1.39e14 exp (34518 J/RT) cm2/s for temperatures between 50 and 400 C, where the activation energies for uraninite are 156.5 and 34.5 kJ/mol, respectively. Results from these new experiments have implications for isotopic exchange during natural UO2 water interactions. The exceptionally low d18O values of natural uraninites (i.e. 32& to 19.5&) from unconformity-type uranium deposits in Saskatchewan, in conjunction with theoretical and experimental uraninite water and UO3 water fractionation factors, suggest that primary uranium mineralization is not in oxygen isotopic equilibrium with coeval clay and silicate minerals. The low d18O values have been interpreted as resulting from the low temperature overprinting of primary uranium mineralization in the presence of relatively modern meteoric fluids having d18O values of ca. 18&, despite petrographic and U Pb isotope data that indicate limited alteration. Our data show that the anomalously low oxygen isotopic composition of the uraninite from the Athabasca Basin can be due to meteoric water overprinting under reducing conditions, and meteoric water or groundwater can significantly affect the oxygen isotopic composition of spent nuclear fuel in a geologic repository, with minimal change to the chemical composition or texture. Moreover, the rather fast oxygen and hydrogen diffusion coefficients for uraninite, especially at low temperatures, suggest that oxygen and hydrogen diffusion may impart characteristic isotopic signals that can be used to track the route of fissile material.

  1. Simulation of xenon, uranium vacancy and interstitial diffusion and grain boundary segregation in UO2

    SciTech Connect (OSTI)

    Andersson, Anders D.; Tonks, Michael R.; Casillas, Luis; Nerikar, Pankaj; Vyas, Shyam; Uberuaga, Blas P.; Stanek, Christopher R.

    2014-10-31

    In light water reactor fuel, gaseous fission products segregate to grain boundaries, resulting in the nucleation and growth of large intergranular fission gas bubbles. Based on the mechanisms established from density functional theory (DFT) and empirical potential calculations 1, continuum models for diffusion of xenon (Xe), uranium (U) vacancies and U interstitials in UO2 have been derived for both intrinsic conditions and under irradiation. Segregation of Xe to grain boundaries is described by combining the bulk diffusion model with a model for the interaction between Xe atoms and three different grain boundaries in UO2 ( ?5 tilt, ?5 twist and a high angle random boundary),as derived from atomistic calculations. All models are implemented in the MARMOT phase field code, which is used to calculate effective Xe and U diffusivities as well as redistribution for a few simple microstructures.

  2. Mechanism of paint removing by organic solvents

    SciTech Connect (OSTI)

    Del Nero, V.; Siat, C.; Marti, M.J.; Aubry, J.M.; Lallier, J.P.; Dupuy, N.; Huvenne, J.P.

    1996-01-01

    The mechanism of paint removing has been studied by comparing the stripping efficiency of a given solvent with its ability to swell the film. The most effective solvents have a Hildebrand{close_quote}s parameter, {delta}{sub H}, ranging from 10.5 to 12 and a Dimroth parameter, ET{sub (30)}, ranging from 0.25 to 0.4. The synergy observed with the mixtures DMSO/non polar solvent is explained by a dissociation of the DMSO clusters into individual molecules which diffuse more easily. {copyright} {ital 1996 American Institute of Physics.}

  3. Mechanical, Industrial & Manufacturing

    E-Print Network [OSTI]

    Balasubramanian, Ravi

    Mechanical, Industrial & Manufacturing Engineering (MIME) COLLEGE OF ENGINEERING FY2013 Oregon graduate degrees (MS, MEng, PhD) in mechanical engineering, industrial engineering, and materials science. We offer bachelor's degrees in mechanical, industrial, manufacturing, and energy systems engineering

  4. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Despite an enormous range of applications and centuries. Nicholas Ouellette is an Associate Professor in the Department of Mechanical Engineering & Materials Structures in Turbulent Flow Nicholas Ouellette Department of Mechanical Engineering & Material Sciences Yale

  5. Mechanical Systems Signal Processing

    E-Print Network [OSTI]

    Verleysen, Michel

    Mechanical Systems and Signal Processing Mechanical Systems and Signal Processing 22 (2008) 155 Department of Mechanical Engineering, University of Sheffield, Mappin Street S1 3JD Sheffield, UK Received 27

  6. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering This presentation presents the stability analysis of time- delay of the Department of Mechanical and Industrial Engineering, Southern Illinois University Edwardsville, where he has Gu Dept. of Mechanical & Industrial Engineering Southern Illinois University, Edwardsville March 27

  7. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering With the increases in computational power and numerical methods a series of research challenges. These challenges involve many branches of mechanical engineering: mechanics, dynamics, tribology, statistical modeling, experimentation, and numerical methods. During

  8. Mechanical & Industrial Engineering

    E-Print Network [OSTI]

    Mountziaris, T. J.

    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

  9. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Today's design environments take advantage of powerful professor of Mechanical Engineering at Carnegie Mellon University. He is the founder of Visual Design award and American Society of Mechanical Engineers Design Automation Society Young Investigator Award

  10. Department of Mechanical & Aerospace

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    in mechanics, electrical theory, kinematics, thermodynamics, fluid mechanics, heat transfer and materials dynamics, fluid dynamics, propulsion and structures. While each program features a solid technicalDeveloping Leaders of Innovation Department of Mechanical & Aerospace Engineering #12;Emphasizing

  11. Diffuse Irradiance Study Planned for October

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalent BondingMeetingDifferences Between Tropical and Trade-Wind3 Diffuse

  12. Adaptive Implicit Non-Equilibrium Radiation Diffusion

    SciTech Connect (OSTI)

    Philip, Bobby [ORNL; Wang, Zhen [ORNL; Berrill, Mark A [ORNL; Rodriguez Rodriguez, Manuel [ORNL; Pernice, Michael [Idaho National Laboratory (INL)

    2013-01-01

    We describe methods for accurate and efficient long term time integra- tion of non-equilibrium radiation diffusion systems: implicit time integration for effi- cient long term time integration of stiff multiphysics systems, local control theory based step size control to minimize the required global number of time steps while control- ling accuracy, dynamic 3D adaptive mesh refinement (AMR) to minimize memory and computational costs, Jacobian Free Newton-Krylov methods on AMR grids for efficient nonlinear solution, and optimal multilevel preconditioner components that provide level independent solver convergence.

  13. Band Formation during Gaseous Diffusion in Aerogels

    E-Print Network [OSTI]

    M. A. Einarsrud; F. A. Maao; A. Hansen; M. Kirkedelen; J. Samseth

    1997-06-18

    We study experimentally how gaseous HCl and NH_3 diffuse from opposite sides of and react in silica aerogel rods with porosity of 92 % and average pore size of about 50 nm. The reaction leads to solid NH_4Cl, which is deposited in thin sheet-like structures. We present a numerical study of the phenomenon. Due to the difference in boundary conditions between this system and those usually studied, we find the sheet-like structures in the aerogel to differ significantly from older studies. The influence of random nucleation centers and inhomogeneities in the aerogel is studied numerically.

  14. ARM - Field Campaign - Diffuse Shortwave IOP

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01) (See22,MicrophysicalgovCampaignsComplexgovCampaignsDiffuse

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

    SciTech Connect (OSTI)

    Neeway, James J.; Kerisit, Sebastien N.; Gin, Stephane; Wang, Zhaoying; Zhu, Zihua; Ryan, Joseph V.

    2014-12-01

    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, it is difficult to conclusively deconvolute the mechanisms of ion exchange from other processes occurring simultaneously during corrosion. In this work, an operationally 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 glass coupons relevant to the immobilization of high-level nuclear waste, SON68 and CJ-6, which contained Li in natural isotope abundance, 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 rapid in both glasses with the simplified CJ-6 glass (D6Li ? 4.0-8.0 × 10-21 m2/s) exhibiting faster exchange than the more complex SON68 glass (DLi ? 2.0-4.0 × 10-21 m2/s). Additionally, sodium ions present in the glass were observed to participate in ion exchange reactions; however, different diffusion coefficients were necessary to fit the diffusion profiles of the two alkali ions. 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.

  16. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The gap between `advanced' prosthetic technology was educated in Mechanical and Biomedical Engineering at the University of Illinois and Northwestern University

  17. Mechanical Performance Extreme Conditions

    E-Print Network [OSTI]

    Mechanical Performance ­ Extreme Conditions METALS This project provides property data, metrology information using the image correlation technique. With this instrument, high strain rate mechanical testing

  18. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering In the pursuit of developing manned, reusable hypersonic will experience thermal and mechanical loads. The research presented will discuss advancements in structural

  19. Low cost fuel cell diffusion layer configured for optimized anode water management

    DOE Patents [OSTI]

    Owejan, Jon P; Nicotera, Paul D; Mench, Matthew M; Evans, Robert E

    2013-08-27

    A fuel cell comprises a cathode gas diffusion layer, a cathode catalyst layer, an anode gas diffusion layer, an anode catalyst layer and an electrolyte. The diffusion resistance of the anode gas diffusion layer when operated with anode fuel is higher than the diffusion resistance of the cathode gas diffusion layer. The anode gas diffusion layer may comprise filler particles having in-plane platelet geometries and be made of lower cost materials and manufacturing processes than currently available commercial carbon fiber substrates. The diffusion resistance difference between the anode gas diffusion layer and the cathode gas diffusion layer may allow for passive water balance control.

  20. Reaction and diffusion in turbulent combustion

    SciTech Connect (OSTI)

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

    1993-12-01

    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.

  1. Generalized Transformation Design: metrics, speeds, and diffusion

    E-Print Network [OSTI]

    Kinsler, Paul

    2015-01-01

    We show that a unified and maximally generalized approach to spatial transformation design is possible, one that encompasses all second order waves, rays, or diffusion processes in anisotropic media. At the design step it is \\emph{not} necessary to specify the physical process for which a specific device will be -- or is intended to be -- built. The primary approximation required is that the effect of wave impedance is neglected, an attribute that plays no role in ray propagation, and therefore is not relevant for pure ray devices; another constraint is that spatial variation in material parameters may need to be sufficiently small. Device construction relies on how we can re-imagine the abstract mathematical notion of a metric on a manifold as a speed-squared matrix (or a diffusion matrix), a step which also specifies the means by which transformation devices will actually be built. Notably, we can conclude that a generalised ray theory that allows for anisotropic indexes (speeds) generates the same predicti...

  2. Distributed Wind Diffusion Model Overview (Presentation)

    SciTech Connect (OSTI)

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

    2014-07-01

    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.

  3. Narrow groove welding gas diffuser assembly and welding torch

    DOE Patents [OSTI]

    Rooney, Stephen J. (East Berne, NY)

    2001-01-01

    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.

  4. Protein motors induced enhanced diffusion in intracellular transport

    E-Print Network [OSTI]

    I. Santamaria-Holek; M. H. Vainstein; J. M. Rubi; F. A. Oliveira

    2009-02-04

    Diffusion of transported particles in the intracellular medium is described by means of a generalized diffusion equation containing forces due to the cytoskeleton network and to the protein motors. We find that the enhanced diffusion observed in experiments depends on the nature of the force exerted by the protein motors and on parameters characterizing the intracellular medium which is described in terms of a generalized Debye spectrum for the noise density of states.

  5. Control of light diffusion in a disordered photonic waveguide

    SciTech Connect (OSTI)

    Sarma, Raktim; Cao, Hui; Golubev, Timofey; Yamilov, Alexey

    2014-07-28

    We control the diffusion of light in a disordered photonic waveguide by modulating the waveguide geometry. In a single waveguide of varying cross-section, the diffusion coefficient changes spatially in two dimensions due to localization effects. The intensity distribution inside the waveguide agrees with the prediction of the self-consistent theory of localization. Our work shows that wave diffusion can be efficiently manipulated without modifying the structural disorder.

  6. A study of diffusion in binary solutions using spin echoes 

    E-Print Network [OSTI]

    Rousseau, Cecil Clyde

    1962-01-01

    of Experimentally Determined Diffusion Coefficients of Cyclohexane and Acetone with the Results of NcCall, Douglass, and Anderson . . . . . . . . . 23 INTRODUCTION The available descriptions of the liquid state form a continuous spectrum that extends from... the liquid with unit velocity. The intrinsic diffusion coefficient is now given by Di kT Equation (1-11) is known as the Einstein relation. Thus far, no explicit statement has been made concerning diffusion in binary systems. In addition to the intrinsic...

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

    Energy Savers [EERE]

    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...

  8. EM Begins Demolishing K-31 Gaseous Diffusion Building | Department...

    Office of Environmental Management (EM)

    East Tennessee Technology Park (ETTP) began Wednesday, marking the removal of the fourth of five gaseous diffusion buildings at the former uranium enrichment site. The...

  9. Diffusion coefficient of three-dimensional Yukawa liquids

    SciTech Connect (OSTI)

    Dzhumagulova, K. N.; Ramazanov, T. S.; Masheeva, R. U. [IETP, Al Farabi Kazakh National University, 71, al Farabi ave., Almaty 050040 (Kazakhstan)] [IETP, Al Farabi Kazakh National University, 71, al Farabi ave., Almaty 050040 (Kazakhstan)

    2013-11-15

    The purpose of this work is an investigation of the diffusion coefficient of the dust component in complex plasma. The computer simulation of the Yukawa liquids was made on the basis of the Langevin equation, which takes into account the influence of buffer plasma on the dust particles dynamics. The Green–Kubo relation was used to calculate the diffusion coefficient. Calculations of the diffusion coefficient for a wide range of the system parameters were performed. Using obtained numerical data, we constructed the interpolation formula for the diffusion coefficient. We also show that the interpolation formula correctly describes experimental data obtained under microgravity conditions.

  10. Optical processing furnace with quartz muffle and diffuser plate

    DOE Patents [OSTI]

    Sopori, Bhushan L. (Denver, CO)

    1995-01-01

    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.

  11. Robust Equilibrated Residual Error Estimator for Diffusion Problems ...

    E-Print Network [OSTI]

    2011-11-11

    Nov 11, 2011 ... Let T = {K} be a finite element partition of the domain ? that is regular, ... dominant diffusion problem are done through a partition of the unity.

  12. COMBUSTION OF COAL IN AN OPPOSED FLOW DIFFUSION BURNER

    E-Print Network [OSTI]

    Chin, W.K.

    2010-01-01

    an Opposed Flow Diffusion Burner Environment Division Chinmodel furnaces, flat flame burners, flow reactors, shocktubes, single particle burners, and, no doubt, others have

  13. Seismic triggering by rectified diffusion in geothermal systems

    E-Print Network [OSTI]

    Sturtevant, Bradford; Kanamori, Hiroo; Brodsky, Emily E.

    1996-01-01

    diffusion in geothermal systems Bradford Sturtevant Graduateof pressure In geothermal systems, fluid flow throughsystems. The modeled geothermal system consists of fractured

  14. 18.366 Random Walks and Diffusion, Spring 2003

    E-Print Network [OSTI]

    Bazant, Martin Z.

    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, ...

  15. 18.366 Random Walks and Diffusion, Spring 2005

    E-Print Network [OSTI]

    Bazant, Martin Z.

    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, ...

  16. Influences of Exciton Diffusion and Exciton-Exciton Annihilation...

    Office of Scientific and Technical Information (OSTI)

    Influences of Exciton Diffusion and Exciton-Exciton Annihilation on Photon Emission Statistics of Carbon Nanotubes Citation Details In-Document Search This content will become...

  17. Fluorescence optical diffusion tomography using multiple-frequency data

    E-Print Network [OSTI]

    .6280, 290.7050, 100.3010, 100.3190, 100.6950, 170.3010, 290.3200. 1. INTRODUCTION Optical diffusion

  18. The Digital Road to Scientific Knowledge Diffusion; A Faster...

    Office of Scientific and Technical Information (OSTI)

    of knowledge. In particular, it is important to understand whether advances in Internet searching can speed up the diffusion of scientific knowledge and accelerate...

  19. Federal Facility Agreement for the Paducah Gaseous Diffusion...

    Office of Environmental Management (EM)

    Federal Facility Agreement for the Paducah Gaseous Diffusion Plant State Kentucky Agreement Type Federal Facility Agreement Legal Driver(s) CERCLARCRA Scope Summary Ensure that...

  20. Diffusion model of the non-stoichiometric uranium dioxide

    SciTech Connect (OSTI)

    Moore, Emily, E-mail: emily.moore@cea.fr [CEA Saclay, DEN-DPC-SCCME, 91191 Gif-sur-Yvette Cedex (France); Guéneau, Christine, E-mail: christine.gueneau@cea.fr [CEA Saclay, DEN-DPC-SCCME, 91191 Gif-sur-Yvette Cedex (France); Crocombette, Jean-Paul, E-mail: jean-paul.crocombette@cea.fr [CEA Saclay, DEN DEN, Service de Recherches de Métallurgie Physique, 91191 Gif-sur-Yvette Cedex (France)

    2013-07-15

    Uranium dioxide (UO{sub 2}), which is used in light water reactors, exhibits a large range of non-stoichiometry over a wide temperature scale up to 2000 K. Understanding diffusion behavior of uranium oxides under such conditions is essential to ensure safe reactor operation. The current understanding of diffusion properties is largely limited by the stoichiometric deviations inherent to the fuel. The present DICTRA-based model considers diffusion across non-stoichiometric ranges described by experimentally available data. A vacancy and interstitial model of diffusion is applied to the U–O system as a function of its defect structure derived from CALPHAD-type thermodynamic descriptions. Oxygen and uranium self and tracer diffusion coefficients are assessed for the construction of a mobility database. Chemical diffusion coefficients of oxygen are derived with respect to the Darken relation and migration energies of defects are evaluated as a function of stoichiometric deviation. - Graphical abstract: Complete description of Oxygen–Uranium diffusion as a function of composition at various temperatures according to the developed Dictra model. - Highlights: • Assessment of a uranium–oxygen diffusion model with Dictra. • Complete description of U–O diffusion over wide temperature and composition range. • Oxygen model includes terms for interstitial and vacancy migration. • Interaction terms between defects help describe non-stoichiometric domain of UO{sub 2±x}. • Uranium model is separated into mobility terms for the cationic species.

  1. Uranium and Strontium Batch Sorption and Diffusion Kinetics into...

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

    Uranium and Strontium Batch Sorption and Diffusion Kinetics into Mesoporous Silica Friday, February 27, 2015 Figure 1 Figure 1. Transmission electron microscopy images of (A)...

  2. Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes...

    Office of Scientific and Technical Information (OSTI)

    Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First Principles and Classical Reactive Molecular Dynamics Citation Details In-Document Search Title: Lithium...

  3. Vapor Barriers or Vapor Diffusion Retarders | Department of Energy

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

    retarders. Materials such as rigid foam insulation, reinforced plastics, aluminum, and stainless steel are relatively resistant to water vapor diffusion. These types of vapor...

  4. Diffusion MRI Methods for Improved Treatment Monitoring in Breast Cancer

    E-Print Network [OSTI]

    Aliu, Sheye

    2009-01-01

    Breast Cancer Overview 2.1 Breast Anatomy . . . . .2.2 Breast Cancer Demographics . . . . . . . . 2.3 Breastii References Diffusion Tensor Imaging in Breast Cancer 5.1

  5. Mechanical Engineering Graduate Student

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    Mechanical Engineering Graduate Student Handbook January 2015 Department of Mechanical Engineering University of Wisconsin-Madison #12;1 Mechanical Engineering Web Page: http://www.engr.wisc.edu/me Graduate & Terrace Chairs) and Samantha Stepp (ME Building) #12;2 Department of Mechanical Engineering AGUIDE

  6. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Bone is a biological material with excellent material properties the properties at lower level serve as inputs for modeling at the next structural level. Mechanical properties and applied mechanics at Northwestern University. Prior to joining the faculty of mechanical engineering

  7. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Strategic Plan 2014-2018 College of Engineering, Architecture & Technology #12;Mechanical and Aerospace Engineering at Oklahoma State University was organized as Mechanical the strongest in the nation. MAE is proud to continue in this fine tradition, forging high quality mechanical

  8. Mechanical Engineering David Sumner

    E-Print Network [OSTI]

    Saskatchewan, University of

    Mechanical Engineering David Sumner david.sumner@usask.ca #12;Mechanical Engineering? · Design, production and use of mechanical systems that control and transform energy · Focused on engineering systems that involve heat, energy and motion · The broadest engineering discipline #12;Subject Areas · Fluid mechanics

  9. Mechanical & Industrial Engineering

    E-Print Network [OSTI]

    Mountziaris, T. J.

    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

  10. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The science of robotics is a unique combination of mechanical in Dayton, OH. Dr. Sodemann received a PhD in Mechanical Engineering from the Georgia Institute to recent advances in the science of robotics, and thus the machines perform primarily as mechanical devices

  11. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Nanocrystal superlattices are materials formed by assembly Professor in the Department of Mechanical Engineering and Applied Mechanics at the University her B.S. in Mechanical Engineering magna cum laude from Rice University in 1994 and was elected to Phi

  12. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering This talk concerns the effective behavior of heterogeneous media Science as well as the Executive Officer for Mechanical and Civil Engineering at the California Institute in Applied Mechanics from the American Society of Mechanical Engineers in 2004. He is currently an Editor

  13. INTRODUCTION TO THE MECHANICS

    E-Print Network [OSTI]

    Kaminski, Edouard

    INTRODUCTION TO THE MECHANICS OF A CONTINUOUS MEDIUM Lawrence E. Malvern Professor of Mechanics princi- ples common to all branches of solid and fluid mechanics, designed to appeal to the intuition science. The book arose from the need to provide a general preparation in contin- uum mechanics

  14. MechanicalEngineering The Department of Mechanical

    E-Print Network [OSTI]

    for the informed development and optimization of materials. This talk will present our recent work on exploring, Ph.D. Associate Professor Department of Mechanical Engineering Department of Materials Science to thermo-mechanical loads is a fundamental requirement in the characterization of materials and structures

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

    E-Print Network [OSTI]

    Kassem, Emad Abdel-Rahman Ahmed

    2011-08-08

    of Core 4 from FW-01 Section ............147 9-1 (a) Seebeck Effect, (b) Peltier Effect (Fredlund and Rahardjo 1993) .................150 9-2 Calibration Curve of Thermocouple Psychrometer ............................................152 9...

  16. Drift and breakup of spiral waves in reaction-diffusion-mechanics systems. A.V. Panfilov

    E-Print Network [OSTI]

    Utrecht, Universiteit

    of electrical activity are thought to lead to life-threatening car- diac arrhythmias [2, 6]. Spiral waves have, the electrical waves initiate muscle contraction resulting in substantial local deforma- tions of mechano-electrical feedback. Mechano-electrical feedback has been studied in electrophysiology for over

  17. On the Mechanism of Carborane Diffusion on a Hydrated Silica Surface Ilya V. Kupchenko,

    E-Print Network [OSTI]

    of R-quartz. Quantum calculations with the CP2K package (cp2k.berlioz.de) have been performed-molecule fluorescence imaging of dye-labeled carbo- rane-wheeled nanocars on a glass surface showed an intensive (4.1 nm

  18. Li ion diffusion mechanism in the crystalline electrolyte -Li3PO4

    E-Print Network [OSTI]

    Holzwarth, Natalie

    -interstitial pair (Frenkel pair), which yields1 kTEEkTE fmm eneT /)2/(/ ~ +-- = For doped crystal. extrinsic

  19. Signal generation mechanisms, intracavity-gas thermal-diffusivity temperature dependence, and absolute infrared emissivity measurements

    E-Print Network [OSTI]

    Mandelis, Andreas

    Diagnostics Laboratories (PODL), University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8 boundary layer adjacent to the cavity thermal source a metallic Cr­Ni alloy strip . This resulted cavity lengths allowed the measurement of the absolute infrared emissivity of the thin Cr­Ni strip source

  20. Stippling the skin: Generation of anatomical periodicity by reaction-diffusion mechanisms 

    E-Print Network [OSTI]

    Headon, Denis J.; Painter, Kevin J.

    2009-01-01

    During vertebrate development cells acquire different fates depending largely on their location in the embryo. The definition of a cell’s developmental fate relies on extensive intercellular communication that produces ...

  1. Continuum Study of Heavy Quark Diffusion

    E-Print Network [OSTI]

    Thomas Neuhaus

    2015-04-28

    We report on a lattice investigation of heavy quark momentum diffusion within the pure SU(3) plasma above the deconfinement transition with the quarks treated to leading order in the heavy mass expansion. We measure the relevant "colour-electric" Euclidean correlator and based on several lattice spacing's perform the continuum extrapolation. This is necessary not only to remove cut-off effects but also the analytic continuation for the extraction of transport coefficients is well-defined only when a continuous function of the Euclidean time variable is available. We pay specific attention to scale setting in SU(3). In particular we present our determination for the critical temperature $T_c=1/({N_\\tau}a) $ at values of $N_\\tau \\le 22$.

  2. Diffuse Radiation from the Aquila Rift

    E-Print Network [OSTI]

    Jyothy, S N; Karuppath, Narayanankutty; Sujatha, N V

    2015-01-01

    We present an analysis of the diffuse ultraviolet (UV) background in a low latitude region near the Aquila Rift based on observations made by the Galaxy Evolution Explorer (GALEX). The UV background is at a level of about 2000 ph cm^-2 s^-1 sr^-1 \\AA^-1 with no correlation with either the Galactic latitude or the 100 micron infrared (IR) emission. Rather, the UV emission falls off with distance from the bright B2 star HIP 88149, which is in the centre of the field. We have used a Monte Carlo model to derive an albedo of 0.6 - 0.7 in the UV with a phase function asymmetry factor (g) of 0.2 - 0.4. The value for the albedo is dependent on the dust distribution while g is determined by the extent of the halo.

  3. Role of Luddism on Innovation Diffusion

    E-Print Network [OSTI]

    Mellor, Andrew; Redner, Sidney; Rucklidge, Alastair M; Ward, Jonathan A

    2015-01-01

    We generalize the classical Bass model of innovation diffusion to include a new class of agents --- Luddites --- that oppose the spread of innovation. Our model also incorporates ignorants, susceptibles, and adopters. When an ignorant and a susceptible meet, the former is converted to a susceptible at a given rate, while a susceptible spontaneously adopts the innovation at a constant rate. In response to the \\emph{rate} of adoption, an ignorant may become a Luddite and permanently reject the innovation. Instead of reaching complete adoption, the final state generally consists of a population of Luddites, ignorants, and adopters. The evolution of this system is investigated analytically and by stochastic simulations. We determine the stationary distribution of adopters, the time needed to reach the final state, and the influence of the network topology on the innovation spread. Our model exhibits an important dichotomy: when the rate of adoption is low, an innovation spreads slowly but widely; in contrast, whe...

  4. Universal energy diffusion in a quivering billiard

    E-Print Network [OSTI]

    Jeffery Demers; Christopher Jarzynski

    2015-09-15

    We introduce and study a model of time-dependent billiard systems with billiard boundaries undergoing infinitesimal wiggling motions. The so-called quivering billiard is simple to simulate, straightforward to analyze, and is a faithful representation of time-dependent billiards in the limit of small boundary displacements. We assert that when a billiard's wall motion approaches the quivering motion, deterministic particle dynamics become inherently stochastic. Particle ensembles in a quivering billiard are shown to evolve to a universal energy distribution through an energy diffusion process, regardless of the billiard's shape or dimensionality, and as a consequence universally display Fermi acceleration. Our model resolves a known discrepancy between the one-dimensional Fermi-Ulam model and the simplified static wall approximation. We argue that the quivering limit is the true fixed wall limit of the Fermi-Ulam model.

  5. Direct molecular diffusion and micro-mixing for rapid dewatering of LiBr solution

    SciTech Connect (OSTI)

    Bigham, S; Isfahani, RN; Moghaddam, S

    2014-03-01

    A slow molecular diffusion rate often limits the desorption process of an absorbate molecule from a liquid absorbent. To enhance the desorption rate, the absorbent is often boiled to increase the liquid vapor interfacial area. However, the growth of bubbles generated during the nucleate boiling process still remains mass-diffusion limited. Here, it is shown that a desorption rate higher than that of boiling can be achieved, if the vapor absorbent interface is continuously replenished with the absorbate-rich solution to limit the concentration boundary layer growth. The study is conducted in a LiBr-water-solution, in which the water molecules' diffusion rate is quite slow. The manipulation of the vapor solution interface concentration distribution is enabled by the mechanical confinement of the solution flow within microchannels, using a hydrophobic vapor-venting membrane and the implementation of microstructures on the flow channel's bottom wall. The microstructures stretch and fold the laminar streamlines within the solution film and produce vortices. The vortices continuously replace the concentrated solution at the vapor solution interface with the water-rich solution brought from the bottom and middle of the flow channel. The physics of the process is described using a combination of experimental and numerical studies. Published by Elsevier Ltd.

  6. Emergence of Quantum Mechanics from a Sub-Quantum Statistical Mechanics

    E-Print Network [OSTI]

    Gerhard Groessing

    2013-04-12

    A research program within the scope of theories on "Emergent Quantum Mechanics" is presented, which has gained some momentum in recent years. Via the modeling of a quantum system as a non-equilibrium steady-state maintained by a permanent throughput of energy from the zero-point vacuum, the quantum is considered as an emergent system. We implement a specific "bouncer-walker" model in the context of an assumed sub-quantum statistical physics, in analogy to the results of experiments by Couder's group on a classical wave-particle duality. We can thus give an explanation of various quantum mechanical features and results on the basis of a "21st century classical physics", such as the appearance of Planck's constant, the Schr\\"odinger equation, etc. An essential result is given by the proof that averaged particle trajectories' behaviors correspond to a specific type of anomalous diffusion termed "ballistic" diffusion on a sub-quantum level. It is further demonstrated both analytically and with the aid of computer simulations that our model provides explanations for various quantum effects such as double-slit or n-slit interference. We show the averaged trajectories emerging from our model to be identical to Bohmian trajectories, albeit without the need to invoke complex wave functions or any other quantum mechanical tool. Finally, the model provides new insights into the origins of entanglement, and, in particular, into the phenomenon of a "systemic" nonlocality.

  7. Mechanisms of light harvesting by photosystem II in plants

    E-Print Network [OSTI]

    Amarnath, Kapil; Schneider, Anna R; Fleming, Graham R

    2015-01-01

    Light harvesting by photosystem II (PSII) in plants is highly efficient and acclimates to rapid changes in the intensity of sunlight. However, the mechanisms of PSII light harvesting have remained experimentally inaccessible. Using a structure-based model of excitation energy flow in 200 nanometer (nm) x 200 nm patches of the grana membrane, where PSII is located, we accurately simulated chlorophyll fluorescence decay data with no free parameters. Excitation movement through the light harvesting antenna is diffusive, but becomes subdiffusive in the presence of charge separation at reaction centers. The influence of membrane morphology on light harvesting efficiency is determined by the excitation diffusion length of 50 nm in the antenna. Our model provides the basis for understanding how nonphotochemical quenching mechanisms affect PSII light harvesting in grana membranes.

  8. DIFFUSING ACOUSTIC WAVE SPECTROSCOPY: FIELD FLUCTUATION SPECTROSCOPY WITH MULTIPLY

    E-Print Network [OSTI]

    Page, John

    DIFFUSING ACOUSTIC WAVE SPECTROSCOPY: FIELD FLUCTUATION SPECTROSCOPY WITH MULTIPLY SCATTERED Martyrs, B.P. 166, 38042 Grenoble Cedex 9, France Abstract. Diffusing Acoustic Wave Spectroscopy (DAWS that acoustic waves, and ultrasonic waves in particular, are playing in understanding the rich diversity of wave

  9. Use of Neural Networks with Advection-Diffusion-Reaction Models

    E-Print Network [OSTI]

    Hawai'i at Manoa, University of

    Use of Neural Networks with Advection-Diffusion-Reaction Models to Estimate Large-Scale Movements-350 #12;Adam, M. S., and J. R. Sibert, Use of Neural Networks with Advection-Diffusion-Reaction Models Motivation 2 2 The model 2 3 Parameterizing movement fields 4 3.1 User of neural networks 5 3.2 Scaling

  10. Transverse Diffusion of Laminar Flow Profiles To Produce Capillary Nanoreactors

    E-Print Network [OSTI]

    Krylov, Sergey

    Transverse Diffusion of Laminar Flow Profiles To Produce Capillary Nanoreactors Victor Okhonin, Xin We introduce transverse diffusion of laminar flow profiles (TDLFP), the first generic method the capillary by pressure as a series of consecutive plugs. Due to the laminar nature of flow inside

  11. Optical processing furnace with quartz muffle and diffuser plate

    DOE Patents [OSTI]

    Sopori, Bhushan L. (Denver, CO)

    1996-01-01

    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.

  12. Peer Effects in the Diffusion of Solar Photovoltaic Panels

    E-Print Network [OSTI]

    Lee, Daeyeol

    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

  13. A Mesoscale Diffusion Model in Population Genetics with

    E-Print Network [OSTI]

    O'Leary, Michael

    ' & $ % A Mesoscale Diffusion Model in Population Genetics with Dynamic Fitness Mike O'Leary Towson University Judith R. Miller Georgetown University 1 #12;A mesoscale diffusion model in population genetics that dominance and epistasis are absent. April 28, 2005 Mike O'Leary and Judith Miller Slide 2 #12;A mesoscale

  14. Diffusion-Induced Ramsey Narrowing Yanhong Xiao,1

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    Diffusion-Induced Ramsey Narrowing Yanhong Xiao,1 Irina Novikova,1 David F. Phillips,1 and Ronald L February 2006) Diffusion-induced Ramsey narrowing is characterized and identified as a general phenomenon of interaction (inside the laser beam), in analogy to Ramsey spectroscopy [4]. In many cases of interest

  15. Hybrid simulations of lateral diffusion in fluctuating membranes

    E-Print Network [OSTI]

    Ellen Reister-Gottfried; Stefan M. Leitenberger; Udo Seifert

    2006-11-21

    In this paper we introduce a novel method to simulate lateral diffusion of inclusions in a fluctuating membrane. The regarded systems are governed by two dynamic processes: the height fluctuations of the membrane and the diffusion of the inclusion along the membrane. While membrane fluctuations can be expressed in terms of a dynamic equation which follows from the Helfrich Hamiltonian, the dynamics of the diffusing particle is described by a Langevin or Smoluchowski equation. In the latter equations, the curvature of the surface needs to be accounted for, which makes particle diffusion a function of membrane fluctuations. In our scheme these coupled dynamic equations, the membrane equation and the Langevin equation for the particle, are numerically integrated to simulate diffusion in a membrane. The simulations are used to study the ratio of the diffusion coefficient projected on a flat plane and the intramembrane diffusion coefficient for the case of free diffusion. We compare our results with recent analytical results that employ a preaveraging approximation and analyze the validity of this approximation. A detailed simulation study of the relevant correlation functions reveals a surprisingly large range where the approximation is applicable.

  16. A Simulation of Moisture Diffusion Process in Furniture-Grade

    E-Print Network [OSTI]

    made for solid wood along the three principal directions Partial vapor pressure ­ the most proper for the moisture diffusion process through MDF using partial vapor pressure as the driving force, and (c/cm/mmHg/Hr) P = partial vapor pressure (mmHg) X = dimension coordinate (cm) Diffusion Cell RH1, P1 RH2, P2 Salt

  17. Research Article A Social Diffusion Model with an Application on

    E-Print Network [OSTI]

    Chen, Sheng-Wei

    may not intuitively interpret such scenario. This work is to design a diffusion model which is capable of managing the aforementioned scenario. To demonstrate the usefulness of our model, we simulate the diffusion Huge success of viral marketing nowadays clearly shows that acquaintances indeed greatly influence

  18. Diffuse optical imaging of the whole head Maria Angela Franceschini

    E-Print Network [OSTI]

    Diffuse optical imaging of the whole head Maria Angela Franceschini Danny K. Joseph Theodore J@nmr.mgh.harvard.edu Abstract. Near-Infrared Spectroscopy NIRS and diffuse optical im- aging DOI are increasingly used to detect of optodes in NIRS instruments has hampered measurement of optical signals from diverse brain regions. Our

  19. A RECONSTRUCTION ALGORITHM FOR ULTRASOUND-MODULATED DIFFUSE OPTICAL

    E-Print Network [OSTI]

    Garnier, Josselin

    A RECONSTRUCTION ALGORITHM FOR ULTRASOUND-MODULATED DIFFUSE OPTICAL TOMOGRAPHY HABIB AMMARI is to develop an efficient reconstruction algorithm for ultrasound-modulated diffuse optical tomography wave is propagating inside the medium, the optical parameter of the medium is perturbed. Using cross

  20. Uranium and cesium diffusion in fuel cladding of electrogenerating channel

    SciTech Connect (OSTI)

    Vasil’ev, I. V. Ivanov, A. S.; Churin, V. A.

    2014-12-15

    The results of reactor tests of a carbonitride fuel in a single-crystal cladding from a molybdenum-based alloy can be used in substantiating the operational reliability of fuels in developing a project of a megawatt space nuclear power plant. The results of experimental studies of uranium and cesium penetration into the single-crystal cladding of fuel elements with a carbonitride fuel are interpreted. Those fuel elements passed nuclear power tests in the Ya-82 pilot plant for 8300 h at a temperature of about 1500°C. It is shown that the diffusion coefficients for uranium diffusion into the cladding are virtually coincident with the diffusion coefficients measured earlier for uranium diffusion into polycrystalline molybdenum. It is found that the penetration of uranium into the cladding is likely to occur only in the case of a direct contact between the cladding and fuel. The experimentally observed nonmonotonic uranium-concentration profiles are explained in terms of predominant uranium diffusion along grain boundaries. It is shown that a substantially nonmonotonic behavior observed in our experiment for the uranium-concentration profile may be explained by the presence of a polycrystalline structure of the cladding in the surface region from its inner side. The diffusion coefficient is estimated for the grain-boundary diffusion of uranium. The diffusion coefficients for cesium are estimated on the basis of experimental data obtained in the present study.

  1. Sorption and Diffusion of Organic Vapors in Two Fluoroelastomers

    E-Print Network [OSTI]

    Wang, Ping

    ; fluoroelastomers; self-diffusion coefficient; in- teraction parameters; barrier properties INTRODUCTION FluorelSorption and Diffusion of Organic Vapors in Two Fluoroelastomers PING WANG,* NATHANIEL S. SCHNEIDER and Aflas are two fluoroelastomers designed to provide superior solvent resistance and, in the case

  2. Hydrodynamics and Fluctuations Outside of Local Equilibrium: Driven Diffusive Systems

    E-Print Network [OSTI]

    ago by Price between the covariance matrix of electrical current noise and the bulk diffusion matrix¨unchen, Germany 1 #12; Abstract We derive hydrodynamic equations for systems not in local thermodynamic systems(DDS), such as electrical conductors in an applied field with diffusion of charge carriers

  3. Kinetic Modeling of Counterflow Diffusion Flames of Butadiene

    E-Print Network [OSTI]

    Senkan, Selim M.

    Kinetic Modeling of Counterflow Diffusion Flames of Butadiene SILVIA GRANATA, TIZIANO FARAVELLI structures of counterflow diffusion and fuel-rich premixed 1,3-butadiene flames, to better understand the need for improved models and also the opportunity of new experiments of butadiene oxidation

  4. Inter-Industry Diffusion of Technology That Results

    E-Print Network [OSTI]

    April 2003 Inter-Industry Diffusion of Technology That Results From ATP Projects ADVANCED TECHNOLOGY PROGRAMADVANCED TECHNOLOGY PROGRAM NIST GCR 03-848 National Institute of Standards and Technology Funding Joel Popkin #12;NIST GCR 03-848 Inter-Industry Diffusion of Technology That Results From ATP

  5. Internal pipe attachment mechanism

    DOE Patents [OSTI]

    Bast, R.M.; Chesnut, D.A.; Henning, C.D.; Lennon, J.P.; Pastrnak, J.W.; Smith, J.A.

    1994-12-13

    An attachment mechanism is described for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection. 6 figures.

  6. Effect of superbanana diffusion on fusion reactivity in stellarators

    SciTech Connect (OSTI)

    Hinton, Fred L. [Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, California 92093-0424 (United States)

    2012-08-15

    Fusion reactivity is usually obtained using a Maxwellian distribution. However, energy-dependent radial diffusion can modify the energy distribution. Superbanana diffusion is energy-dependent and occurs in nonaxisymmetric magnetic confinement devices, such as stellarators, because of ripple-trapped particles which can take large steps between collisions. In this paper, the D-T fusion reactivity is calculated using a non-Maxwellian energy distribution obtained by solving the Fokker-Planck equation numerically, including radial superbanana diffusion as well as energy scattering. The ions in the tail of the distribution, with energies larger than thermal, which are most needed for fusion, are depleted by superbanana diffusion. In this paper, it is shown that the D-T fusion reactivity is reduced by tail ion depletion due to superbanana diffusion, by roughly a factor of 0.5 for the parameters used in the calculation.

  7. SRS history and experience with palladium diffusers. Revision 1

    SciTech Connect (OSTI)

    Clark, E.A.; Dauchess, D.A.; Heung, L.K.; Rabun, R.L.; Motyka, T.

    1995-08-11

    The Savannah River Site (SRS) has processed tritium in support of national defense programs since 1955. Palladium diffusers have been used extensively for separating hydrogen isotopes from inert gases (such as argon, helium, and nitrogen). In almost forty years of service, the design of the diffuser has been steadily improving. Several diffuser designs from different manufacturers have been evaluated at SRS. The operating experience gained from these designs together with failure analyses performed on failed units have led to several recommendations for improved diffuser designs and operating methods. This experience gained at SRS and the following recommendations form the basis of this report. Even though palladium diffuser technology has proven to be reliable, SRS has examined several alternative technologies over the past several years. This report will also review some of these promising alternatives.

  8. Grain boundary and triple junction diffusion in nanocrystalline copper

    SciTech Connect (OSTI)

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

    2014-09-07

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

  9. Chemical and mechanical instability in warm and dense nuclear matter

    E-Print Network [OSTI]

    Lavagno, A; 10.1103/PhysRevC.86.024917

    2012-01-01

    We investigate the possible thermodynamic instability in a warm and dense nuclear medium (Tliquid-gas phase transition, we show that the nucleon-Delta matter phase transition is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the charge concentration) in asymmetric nuclear matter. We then perform an investigation and a comparative study on the different nature of such instabilities and phase transitions.

  10. Fabrication and Design Aspects of High-Temperature Compact Diffusion Bonded Heat Exchangers

    SciTech Connect (OSTI)

    Mylavarapu, Sai K.; Sun, Xiaodong; Christensen, Richard N.; Glosup, Richard E.; Unocic, Raymond R

    2012-01-01

    The very high temperature reactor (VHTR), using gas-cooled reactor technology, is one of the six reactor concepts selected by the Generation IV International Forum and is anticipated to be the reactor type for the next generation nuclear plant (NGNP). In this type of reactor with an indirect power cycle system, a high-temperature and high integrity intermediate heat exchanger (IHX) with high effectiveness is required to efficiently transfer the core thermal output to secondary fluid for electricity production, process heat, or hydrogen cogeneration. The current Technology Readiness Level status issued by NGNP to all components associated with the IHX for reactor core outlet temperatures of 750-800oC is 3 on a scale of 1 to 10 with 10 being the most ready. At present, there is no proven high-temperature IHX concept for VHTRs. Amongst the various potential IHX concepts available, diffusion bonded heat exchangers (henceforth called printed circuit heat exchangers, or PCHEs) appear promising for NGNP applications. The design and fabrication of this key component of NGNP is the primary focus of this paper. In the current study, two PCHEs were fabricated using Alloy 617 plates and will be experimentally investigated for their thermal-hydraulic performance in a high-temperature helium test facility (HTHF). The HTHF was primarily designed and constructed to test the thermal-hydraulic performance of PCHEs The test facility is primarily of Alloy 800H construction and is designed to facilitate experiments at temperatures and pressures up to 800oC and 3 MPa, respectively. The PCHE fabrication related processes, i.e., photochemical machining and diffusion bonding are briefly discussed for Alloy 617 plates. Diffusion bonding of Alloy 617 plates with and without a Ni interlayer is discussed. Furthermore, preliminary microstructural and mechanical characterization studies of representative diffusion bonded Alloy 617 specimens are presented.

  11. MechanicalEngineering Colloquium The Department of Mechanical

    E-Print Network [OSTI]

    MechanicalEngineering Colloquium The Department of Mechanical Engineering PRESENTS John C. Bischof Distinguished Professor Mechanical and Biomedical Engineering Chair, Mechanical Engineering University in the Departments of Mechanical and Biomedical Engineering and the inaugural Carl and Janet Kuhrmeyer Chair

  12. Diffusive Shock Acceleration of Electrons and Radio Emission from Large Diameter Shell-Type Supernova Remnants

    E-Print Network [OSTI]

    A. I. Asvarov

    2000-01-21

    In present study I examine the capability of diffusive shock acceleration mechanism to explain existing data on radio emission from evolved large diameter shell-type adiabatic supernova remnants (SNRs). Time-dependent ''onion-shell'' model for the radio emission of SNRs is developed, which is based on the assumptions: a) acceleration takes place from thermal energies and test-particle approximation is valid; b) the problem of injection is avoided by introducing, like Bell (1978), two injection parameters; c) to take into consideration very late stages of SNR evolution the analytic approximation of Cox and Andersen (1982) for the shell structure is used; c)no radiative cooling. Constructed Surface Brightness - Diameter $(\\Sigma -D)$ tracks are compared with the empirical $\\Sigma -D$ diagram. The main conclusion of the study is that the DSA mechanism is capable of explaining all the statistics of radio SNRs including very large diameter remnants and giant galactic loops.

  13. Diffusion-controlled generation of a proton-motive force across a biomembrane

    E-Print Network [OSTI]

    Anatoly Yu. Smirnov; Sergey E. Savel'ev; Franco Nori

    2009-12-04

    Respiration in bacteria involves a sequence of energetically-coupled electron and proton transfers creating an electrochemical gradient of protons (a proton-motive force) across the inner bacterial membrane. With a simple kinetic model we analyze a redox loop mechanism of proton-motive force generation mediated by a molecular shuttle diffusing inside the membrane. This model, which includes six electron-binding and two proton-binding sites, reflects the main features of nitrate respiration in E. coli bacteria. We describe the time evolution of the proton translocation process. We find that the electron-proton electrostatic coupling on the shuttle plays a significant role in the process of energy conversion between electron and proton components. We determine the conditions where the redox loop mechanism is able to translocate protons against the transmembrane voltage gradient above 200 mV with a thermodynamic efficiency of about 37%, in the physiologically important range of temperatures from 250 to 350 K.

  14. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering We introduce phonon recycling (local reabsorption of emitted) is Professor in Department of Mechanical Engineering and in Applied Physics Program, University of Michigan of Mechanical Engineering University of Michigan November 1, 2013 at 1:30pm in SCOB 228 School for Engineering

  15. Mechanical and Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical and Aerospace Engineering seminar Manipulation of Energy and Mass Transport at Micro as an assistant professor in the Department of Mechanical Engineering and was promoted to an associate professor award in 2007. Dr. Deyu Li Department of Mechanical Engineering Vanderbilt University January 20, 2012

  16. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Thermal transport plays an important role in energy conversion conductivity and phonon transport mechanisms over the past 2 decades, owing much to the challenging needs Faculty Fellow in Engineering and an Associate Professor of Mechanical Engineering directing the Nano

  17. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Interfacial flows are multi-material flows comprised of two and Solid Mechanics group in the Theoretical Division. Her research focuses on the development of numerical, and nuclear energy. She is a member of the American Society of Mechanical Engineers (ASME), Fluids Engineering

  18. Department of Mechanical and

    E-Print Network [OSTI]

    Huang, Jianwei

    Department of Mechanical and Automation Engineering #12;4 2 3 1 Contents Messages in the souvenir publication of the Department of Mechanical and Automation Engineering of The Chinese University of Mechanical and Automation Engineering have also played a significant part in equipping businesses

  19. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Much of past research in structural dynamics (and many other the University of Liege, Belgium, in 1983 and his Ph.D. in mechanical engineering from Rice University in 1987. He then joined the rather newly formed Department of Mechanical and Aerospace Engineering at ASU

  20. TOWARDS MECHANICAL METAMATHEMATICS

    E-Print Network [OSTI]

    Boyer, Robert Stephen

    TOWARDS MECHANICAL METAMATHEMATICS N. Shankar Technical Report 43 December 1984 Institute application of certain mechanical rules of inference. The derivations of theorems from the axioms are termed of a valid mathematical argument. Another advantage of formal proofs is that they can be mechanically checked

  1. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering It has been demonstrated that the color pattern of the human received the B.A. degree in physics from Houghton College, Houghton, NY, and the B.S. degree in mechanical in mechanical engineering from the Massachusetts Institute of Technology (MIT), Cambridge, MA, in 1997 and 2002

  2. A mechanical encapsulatio n

    E-Print Network [OSTI]

    Jackson, Trachette L.

    A mechanical mo delo f tumo r encapsulatio n and transcapsular spread Trachette L. Jackso n a 48109­1109, USA b Division of Theoretical Mechanics, School of Mathematical Sciences, University rmatio n, such investigatio ns being ideally suited to o ur mechanical mo del. The mo del simulatio ns

  3. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Fragmentation is a process in which structures fail in a very Engineering at Duke University, where he directs the Duke Computational Mechanics Laboratory. Professor Dolbow received his BS in Mechanical Engineering from the University of New Hampshire in 1995, and his Ph

  4. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The miniaturization of structural components to the sub progress in strain-gradient continuum theories to model the mechanical behavior of metallic systems at small length scales, these theories fail to represent the variety of physical mechanisms involved

  5. Mechanical Engineering Assistant Professor

    E-Print Network [OSTI]

    Chandy, John A.

    Mechanical Engineering Xu Chen Assistant Professor xchen@uconn.edu http://xchen.lab.uconn.edu From Engineering Ingredients of Kung Pao Chicken Marinade · 1 tablespoon soy sauce · 2 teaspoons Chinese rice wine of Diana Kuan #12;Mechanical Engineering The Cooking Procedure #12;Mechanical Engineering The Difference

  6. Mechanical & Industrial Engineering

    E-Print Network [OSTI]

    Mountziaris, T. J.

    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

  7. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Pool boiling heat transfer enhancement is taking a dramatic turn Mechanical Engineering Rochester Institute of Technology September 5, 2014 at 1:30pm in SCOB 210 School from the classical area enhancement and nucleation cavity augmentation to mechanism based

  8. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Energetic materials that include nano-scale aluminum (Al and joined the faculty in the Mechanical Engineering Department at Texas Tech University in 2000 Pantoya Dept. of Mechanical Engineering Texas Tech University April 19, 2013 at 1:30pm in LSE 106 School

  9. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The presentation will first review emerging joint time in Mechanical Engineering and Engineering Science from the Technical University in Athens, Greece and his, vehicle engineering, bio-mechanics, and composite materials. He is Editor-in-Chief of the International

  10. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The state of the art in Quantification of Margin and UncertaintyD in Engineering Mechanics from the University of Wisconsin in 1978. He then worked in research laboratories of the University of Wisconsin as a Senior Scientist. In March of this year, he joined the Mechanical Engineering

  11. Mechanical and Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical and Aerospace Engineering seminar From Jumping Drops to Thermal Diodes Abstract Scholar and Assistant Professor of Mechanical Engineering and Materials Science at Duke University since.D. degree in Mechanical Engineering from Stanford University (2004). Dr. Chen is a recipient of numerous

  12. Mechanical and Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical and Aerospace Engineering seminar Some Forward-Looking Assistive Devices to Improve. Biosketch Michael Goldfarb, PhD, is the H. Fort Flowers Professor of Mechanical Engineering and the director in Mechanical Engineering from the University of Arizona in 1988, and received his SM and PhD degrees

  13. Mechanical and Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical and Aerospace Engineering seminar Plasma Actuators for Aerodynamic Flow Control.D. in Mechanical Engineering from The Ohio State University in 2004, 2005 and 2010 respectively. He joined the Department of Aerospace and Mechanical Engineering at the University of Arizona in 2010 as an Assistant

  14. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The atomization of a liquid jet by a high speed cross.S.E. degree in mechanical engineering from Amirkabir University of Technology in 2006 and M.S. degree in mechanical engineering from Sharif University of Technology in 2009. He is currently a Ph.D. candidate

  15. QUICK QUANTUM MECHANICS ---Introduction ---

    E-Print Network [OSTI]

    Jackson, Andrew D.

    QUICK QUANTUM MECHANICS --- Introduction --- The following notes are intended to be a supplement to your study of Liboff's ``Introductory Quantum Mechanics.'' They are not an alternative! My purpose here of Classical Mechanics After Newton found his equations of motion, physicists knew they would have to wait

  16. Introduction to Quantum Mechanics

    E-Print Network [OSTI]

    Eduardo J. S. Villaseñor

    2008-04-23

    The purpose of this contribution is to give a very brief introduction to Quantum Mechanics for an audience of mathematicians. I will follow Segal's approach to Quantum Mechanics paying special attention to algebraic issues. The usual representation of Quantum Mechanics on Hilbert spaces is also discussed.

  17. Mechanical Systems Signal Processing

    E-Print Network [OSTI]

    Carvalho, João B.

    , Northern Illinois University, DeKalb, IL 60115, USA c Department of Mechanical Engineering & VibrationMechanical Systems and Signal Processing Mechanical Systems and Signal Processing 21 (2007) 2715 Federal de Rio Grande do Sul, Brazil b Department of Mathematical Sciences & Vibration and Acoustic Center

  18. Remark on laser linewidth hazard in opto-mechanical cooling

    E-Print Network [OSTI]

    Lajos Diósi

    2008-07-23

    I discuss the robustness of the pumped cavity dynamics against phase diffusion of the laser and conclude that opto-mechanical cooling has extreme sensitivity compared to laser cooling of atoms. Certain proposals of ground state opto-mechanical cooling by single cavity would require an unrealistic sharp laser linewidth or equivalently, a very low level of phase noise. A systematic way to cancel classical excess phase noise is the interferometric twin-cavity pumping, initiated for optically trapped macro-mirrors of future gravitational-wave detectors.

  19. APRIORI BOUNDS FOR REACTION-DIFFUSION SYSTEMS ARISING IN CHEMICAL JEFF S. MCGOUGH AND KYLE RILEY

    E-Print Network [OSTI]

    McGough, Jeff S.

    APRIORI BOUNDS FOR REACTION-DIFFUSION SYSTEMS ARISING IN CHEMICAL KINETICS JEFF S. MCGOUGH AND KYLE RILEY Abstract. The authors investigate reaction diffusion equations which arise in chemical kinetics diffusion equations, gradient bounds, chemical kinetics, autocatalytic reactions AMS subject classifications

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

    E-Print Network [OSTI]

    Shuckburgh, Emily

    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 ...

  1. Irreversible reactions and diffusive escape: Stationary properties

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

    Krapivsky, Paul L.; Ben-Naim, Eli

    2015-05-01

    We study three basic diffusion-controlled reaction processes—annihilation, coalescence, and aggregation. We examine the evolution starting with the most natural inhomogeneous initial configuration where a half-line is uniformly filled by particles, while the complementary half-line is empty. We show that the total number of particles that infiltrate the initially empty half-line is finite and has a stationary distribution. We determine the evolution of the average density from which we derive the average total number N of particles in the initially empty half-line; e.g. for annihilation $\\langle N\\rangle = \\frac{3}{16}+\\frac{1}{4\\?}$ . For the coalescence process, we devise a procedure that in principlemore »allows one to compute P(N), the probability to find exactly N particles in the initially empty half-line; we complete the calculations in the first non-trivial case (N = 1). As a by-product we derive the distance distribution between the two leading particles.« less

  2. Thick diffusion limit boundary layer test problems

    SciTech Connect (OSTI)

    Bailey, T. S.; Warsa, J. S.; Chang, J. H.; Adams, M. L.

    2013-07-01

    We develop two simple test problems that quantify the behavior of computational transport solutions in the presence of boundary layers that are not resolved by the spatial grid. In particular we study the quantitative effects of 'contamination' terms that, according to previous asymptotic analyses, may have a detrimental effect on the solutions obtained by both discontinuous finite element (DFEM) and characteristic-method (CM) spatial discretizations, at least for boundary layers caused by azimuthally asymmetric incident intensities. Few numerical results have illustrated the effects of this contamination, and none have quantified it to our knowledge. Our test problems use leading-order analytic solutions that should be equal to zero in the problem interior, which means the observed interior solution is the error introduced by the contamination terms. Results from DFEM solutions demonstrate that the contamination terms can cause error propagation into the problem interior for both orthogonal and non-orthogonal grids, and that this error is much worse for non-orthogonal grids. This behavior is consistent with the predictions of previous analyses. We conclude that these boundary layer test problems and their variants are useful tools for the study of errors that are introduced by unresolved boundary layers in diffusive transport problems. (authors)

  3. Chaotic Diffusion of Resonant Kuiper Belt Objects

    E-Print Network [OSTI]

    Matthew S. Tiscareno; Renu Malhotra

    2009-07-06

    We carried out extensive numerical orbit integrations to probe the long-term chaotic dynamics of the two strongest mean motion resonances of Neptune in the Kuiper belt, the 3:2 (Plutinos) and 2:1 (Twotinos). Our primary results include a computation of the relative volumes of phase space characterized by large- and small-resonance libration amplitudes, and maps of resonance stability measured by mean chaotic diffusion rate. We find that Neptune's 2:1 resonance has weaker overall long-term stability than the 3:2 -- only ~15% of Twotinos are projected to survive for 4 Gyr, compared to ~27% of Plutinos, based on an extrapolation from our 1-Gyr integrations. We find that Pluto has only a modest effect, causing a ~4% decrease in the Plutino population that survives to 4 Gyr. Given current observational estimates, and assuming an initial distribution of particles proportional to the local phase space volume in the resonance, we conclude that the primordial populations of Plutinos and Twotinos formerly made up more than half the population of the classical and resonant Kuiper Belt. We also conclude that Twotinos were originally nearly as numerous as Plutinos; this is consistent with predictions from early models of smooth giant planet migration and resonance sweeping of the Kuiper Belt, and provides a useful constraint for more detailed models.

  4. Puzzling Phenomenon of Diffuse Interstellar Bands

    E-Print Network [OSTI]

    B. Wszolek

    2007-12-10

    The discovery of the first diffuse interstellar bands (DIBs) dates back to the pioneering years of stellar spectroscopy. Today, we know about 300 absorption structures of this kind. There exists a great variety of the profiles and intensities of DIBs, so they can not be readily described, classified or characterized. To the present day no reliable identification of the DIBs' carriers has been found. Many carriers of DIBs have been proposed over the years. They ranged from dust grains to free molecules of different kinds, and to more exotic specimens, like hydrogen negative ion. Unfortunately, none of them is responsible for observed DIBs. Furthermore, it was shown that a single carrier cannot be responsible for all known DIBs. It is hard to estimate how many carriers can participate in producing these bands. The problem is further complicated by the fact that to this day it is still impossible to find any laboratory spectrum of any substance which would match the astrophysical spectra. Here, a historical outline concerning DIBs is followed by a brief description of their whole population. Then, a special attention is focused on the procedures trying to extract spectroscopic families within the set of all known DIBs.

  5. Linear diffusion into a Faraday cage.

    SciTech Connect (OSTI)

    Warne, Larry Kevin; Lin, Yau Tang; Merewether, Kimball O.; Chen, Kenneth C.

    2011-11-01

    Linear lightning diffusion into a Faraday cage is studied. An early-time integral valid for large ratios of enclosure size to enclosure thickness and small relative permeability ({mu}/{mu}{sub 0} {le} 10) is used for this study. Existing solutions for nearby lightning impulse responses of electrically thick-wall enclosures are refined and extended to calculate the nearby lightning magnetic field (H) and time-derivative magnetic field (HDOT) inside enclosures of varying thickness caused by a decaying exponential excitation. For a direct strike scenario, the early-time integral for a worst-case line source outside the enclosure caused by an impulse is simplified and numerically integrated to give the interior H and HDOT at the location closest to the source as well as a function of distance from the source. H and HDOT enclosure response functions for decaying exponentials are considered for an enclosure wall of any thickness. Simple formulas are derived to provide a description of enclosure interior H and HDOT as well. Direct strike voltage and current bounds for a single-turn optimally-coupled loop for all three waveforms are also given.

  6. Irreversible Reactions and Diffusive Escape: Stationary Properties

    E-Print Network [OSTI]

    P. L. Krapivsky; E. Ben-Naim

    2015-03-24

    We study three basic diffusion-controlled reaction processes -- annihilation, coalescence, and aggregation. We examine the evolution starting with the most natural inhomogeneous initial configuration where a half-line is uniformly filled by particles, while the complementary half-line is empty. We show that the total number of particles that infiltrate the initially empty half-line is finite and has a stationary distribution. We determine the evolution of the average density from which we derive the average total number N of particles in the initially empty half-line; e.g., for annihilation \\langle N\\rangle = 3/16+1/(4\\pi). For the coalescence process, we devise a procedure that in principle allows one to compute P(N), the probability to find exactly N particles in the initially empty half-line; we complete the calculations in the first non-trivial case (N=1). As a by-product we derive the distance distribution between the two leading particles.

  7. Diffusivity bounds for 1D Brownian polymers

    E-Print Network [OSTI]

    Pierre Tarrès; Bálint Tóth; Benedek Valkó

    2012-06-08

    We study the asymptotic behavior of a self-interacting one-dimensional Brownian polymer first introduced by Durrett and Rogers [Probab. Theory Related Fields 92 (1992) 337--349]. The polymer describes a stochastic process with a drift which is a certain average of its local time. We show that a smeared out version of the local time function as viewed from the actual position of the process is a Markov process in a suitably chosen function space, and that this process has a Gaussian stationary measure. As a first consequence, this enables us to partially prove a conjecture about the law of large numbers for the end-to-end displacement of the polymer formulated in Durrett and Rogers [Probab. Theory Related Fields 92 (1992) 337--349]. Next we give upper and lower bounds for the variance of the process under the stationary measure, in terms of the qualitative infrared behavior of the interaction function. In particular, we show that in the locally self-repelling case (when the process is essentially pushed by the negative gradient of its own local time) the process is super-diffusive.

  8. Continuum modeling of diffusion and dispersion in dense granular...

    Office of Scientific and Technical Information (OSTI)

    Author Affiliations Los Alamos National Laboratory Los Alamos National Laboratory Mechanical & Aerospace Engineering, Princeton University Mechanical & Aerospace Engineering,...

  9. Mechanical seal assembly

    DOE Patents [OSTI]

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

    2002-01-01

    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.

  10. Mechanical seal assembly

    DOE Patents [OSTI]

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

    2001-01-01

    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.

  11. Non-Brownian molecular self-diffusion in bulk water

    E-Print Network [OSTI]

    Janez Stepišnik; Aleš Mohori?; Igor Serša

    2010-10-06

    The paper presents the velocity autocorrelation spectrum of bulk water measured by a new technique of NMR modulated gradient spin echo method. This technique is unprecedented for the spectrum measurement in the frequency interval between a few Hz to about 100 kHz with respect to directness and clarity of results and shows that a simple model of Brownian self-diffusion is not applicable to describe the diffusion dynamics of water molecules. The observed temperature dependant spectra of water show the existence of a slow chain-like dynamics in water, which we explain by coupling of diffusing molecule to broken bonds in the hydrogen bond network.

  12. Diffusive mesh relaxation in ALE finite element numerical simulations

    SciTech Connect (OSTI)

    Dube, E.I.

    1996-06-01

    The theory for a diffusive mesh relaxation algorithm is developed for use in three-dimensional Arbitary Lagrange/Eulerian (ALE) finite element simulation techniques. This mesh relaxer is derived by a variational principle for an unstructured 3D grid using finite elements, and incorporates hourglass controls in the numerical implementation. The diffusive coefficients are based on the geometric properties of the existing mesh, and are chosen so as to allow for a smooth grid that retains the general shape of the original mesh. The diffusive mesh relaxation algorithm is then applied to an ALE code system, and results from several test cases are discussed.

  13. Jump-Diffusion Risk-Sensitive Asset Management II: Jump-Diffusion Factor Model

    E-Print Network [OSTI]

    Davis, Mark

    2011-01-01

    In this article we extend earlier work on the jump-diffusion risk-sensitive asset management problem [SIAM J. Fin. Math. (2011) 22-54] by allowing jumps in both the factor process and the asset prices, as well as stochastic volatility and investment constraints. In this case, the HJB equation is a partial integro-differential equation (PIDE). By combining viscosity solutions with a change of notation, a policy improvement argument and classical results on parabolic PDEs we prove that the HJB PIDE admits a unique smooth solution. A verification theorem concludes the resolution of this problem.

  14. A LOCAL PROJECTION STABILIZATION FINITE ELEMENT METHOD WITH NONLINEAR CROSSWIND DIFFUSION FOR

    E-Print Network [OSTI]

    John, Volker

    A LOCAL PROJECTION STABILIZATION FINITE ELEMENT METHOD WITH NONLINEAR CROSSWIND DIFFUSION and phrases. finite element method; local projection stabilization; crosswind diffusion; convection

  15. Protein Diffusiophoresis and Salt Osmotic Diffusion in Aqueous Onofrio Annunziata,* Daniela Buzatu,

    E-Print Network [OSTI]

    Annunziata, Onofrio

    Protein Diffusiophoresis and Salt Osmotic Diffusion in Aqueous Solutions Onofrio Annunziata salt osmotic diffusion induced by a protein concentration gradient, and is related to protein

  16. X. CORRELATIONS BETWEEN DIFFUSE AND GLOBAL IRRADIANCE For numerous applications, particularly those

    E-Print Network [OSTI]

    Oregon, University of

    33 X. CORRELATIONS BETWEEN DIFFUSE AND GLOBAL IRRADIANCE For numerous applications, particularly these components, values for direct beam and diffuse irradiance are usu- ally unavailable. However, considerable in

  17. A Simulation Study of Diffusion in Microporous Materials

    E-Print Network [OSTI]

    Abouelnasr, Mahmoud Kamal Forrest

    2013-01-01

    of new zeolite-like materials. Phys. Chem. Chem. Phys. 13,screening of carbon-capture materials. Nat. Mater. 11, 633–Diffusion in nanoporous materials. (Wiley- VCH, 2012). 48.

  18. Overcoming the Exciton Diffusion Bottleneck in Organic Photovoltaic...

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

    Overcoming the Exciton Diffusion Bottleneck in Organic Photovoltaic Cells May 20, 2009 at 3pm36-428 Russell J.Holmes Department of Chemical Engineering and Materials Science,...

  19. Thermodynamic properties and diffusion of water + methane binary mixtures

    SciTech Connect (OSTI)

    Shvab, I.; Sadus, Richard J.

    2014-03-14

    Thermodynamic and diffusion properties of water + methane mixtures in a single liquid phase are studied using NVT molecular dynamics. An extensive comparison is reported for the thermal pressure coefficient, compressibilities, expansion coefficients, heat capacities, Joule-Thomson coefficient, zero frequency speed of sound, and diffusion coefficient at methane concentrations up to 15% in the temperature range of 298–650 K. The simulations reveal a complex concentration dependence of the thermodynamic properties of water + methane mixtures. The compressibilities, heat capacities, and diffusion coefficients decrease with increasing methane concentration, whereas values of the thermal expansion coefficients and speed of sound increase. Increasing methane concentration considerably retards the self-diffusion of both water and methane in the mixture. These effects are caused by changes in hydrogen bond network, solvation shell structure, and dynamics of water molecules induced by the solvation of methane at constant volume conditions.

  20. Multiple scattering of classical waves: microscopy, mesoscopy, and diffusion 

    E-Print Network [OSTI]

    van Rossum, Mark; Nieuwenhuizen, Th.M

    1999-01-01

    A tutorial discussion of the propagation of waves in random media is presented. To a first approximation the transport of the multiple scattered waves is given by diffusion theory, but important corrections are presented. ...

  1. Demolition of K-31 gaseous diffusion building begins | Department...

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

    OREM began demolition of the 750,000 sq. ft. K-31 Building, marking the removal of the fourth of five gaseous diffusion buildings at the former uranium enrichment site. OREM began...

  2. Diffuse Atomic and Molecular Theodore P. Snow1

    E-Print Network [OSTI]

    McCall, Benjamin J.

    Diffuse Atomic and Molecular Clouds Theodore P. Snow1 and Benjamin J. McCall2 1 Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, Colorado 80309; email: theodore.snow

  3. International diffusion practice : lessons from South Korea's New Village Movement

    E-Print Network [OSTI]

    Kim, Jung Hwa, M.C.P. Massachusetts Institute of Technology

    2013-01-01

    This research focuses on how South Korea's development model-namely, the Saemaul Undong, or the New Village Movement-is diffused internationally, in particular, to the developing country of Vietnam. South Korea's successful ...

  4. Transportation cost inequalities for diffusions under uniform distance

    E-Print Network [OSTI]

    Ali Suleyman Ustunel

    2010-11-04

    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.

  5. Discretisation and solution of quasi-diffusion equations 

    E-Print Network [OSTI]

    Valette, Nicolas Dominique

    2002-01-01

    We show how the Quasi-diffusion method performs on radiative transfer problems in slab geometry and XY geometry for steady state, one-energy-group problems. We explain first how we derive for slab geometry, the discretization we use...

  6. Measurement and Modeling of Solute Diffusion Coefficients in Unsaturated Soils

    E-Print Network [OSTI]

    Chou, Hsin-Yi

    2010-01-01

    Diffusion and flow in gravel, soil, and whole rock, AppliedEds. ) (2002), Methods of Soil Analysis Part 4 PhysicalUnsaturated Volcanic Ash Soils, Vadose Zone Journal, 8(4),

  7. Measure of Diffusion Model Error for Thermal Radiation Transport 

    E-Print Network [OSTI]

    Kumar, Akansha

    2013-04-19

    and computational time. However, this approximation often has significant error. Error due to the inherent nature of a physics model is called model error. Information about the model error associated with the diffusion approximation is clearly desirable...

  8. Integration by Parts and Time Reversal for Diffusion Processes

    E-Print Network [OSTI]

    Millet, A.; Nualart, David; Sanz, M.

    1989-01-05

    In this paper we obtain necessary and sufficient conditions for the reversibility of the diffusion property, assuming the existence of a density at every time t. The proofs are based on techniques of the stochastic calculus ...

  9. PIECEWISELINEAR DIFFUSION PROCESSES Sid Browne and Ward Whitt

    E-Print Network [OSTI]

    Whitt, Ward

    PIECEWISE­LINEAR DIFFUSION PROCESSES by Sid Browne and Ward Whitt Graduate School of Business AT&T Bell Laboratories Columbia University Murray Hill, NJ 07974­0636 New York, NY 10027 May 17, 1994 #12

  10. Fractional Classical Mechanics

    E-Print Network [OSTI]

    Nick Laskin

    2013-02-03

    Fractional classical mechanics has been introduced and developed as a classical counterpart of the fractional quantum mechanics. Lagrange, Hamilton and Hamilton-Jacobi frameworks have been implemented for the fractional classical mechanics. The Lagrangian of fractional classical mechanics has been introduced, and equation of motion has been obtained. Fractional oscillator model has been launched and solved in 1D case. A new equation for the period of oscillations of fractional classical oscillator has been found. The interplay between the energy dependency of the period of classical oscillations and the non-equidistant distribution of the energy levels for fractional quantum oscillator has been discussed. We discuss as well, the relationships between new equations of fractional classical mechanics and the well-known fundamental equations of classical mechanics.

  11. Mechanical Properties of Nanocrystal Supercrystals

    E-Print Network [OSTI]

    Tam, Enrico

    2010-01-01

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

  12. Statistical mechanics of the cytoskeleton

    E-Print Network [OSTI]

    Wang, Shenshen

    2012-01-01

    mechanics . . . . . . . . . . . . . . . . . . . . . . 2.1bottom-up approach to cell mechanics. Nat. Phys. [6] Fabry,Wolynes, P. G. Statistical mechanics of a cat’s cradle. New

  13. Hard Evidence and Mechanism Design

    E-Print Network [OSTI]

    Watson, Joel; Bull, Jesse

    2006-01-01

    J. , 2003. Contract, mechanism design, and technologicalSeverinov, S. , 2001. Mechanism design and communicationveri?able information and mechanism design. Rev. Econ. Stud.

  14. Hard Evidence and Mechanism Design

    E-Print Network [OSTI]

    Bull, J; Watson, J

    2007-01-01

    J. , 2003. Contract, mechanism design, and technologicalSeverinov, S. , 2001. Mechanism design and communicationveri?able information and mechanism design. Rev. Econ. Stud.

  15. A fluid mechanical explanation of dark matter

    E-Print Network [OSTI]

    Carl H. Gibson

    1999-04-22

    Matter in the universe has become ``dark'' or ``missing'' through misconceptions about the fluid mechanics of gravitational structure formation. Gravitational condensation occurs on non-acoustic density nuclei at the largest Schwarz length scale L_{ST}, L_{SV}, L_{SM}, L_{SD} permitted by turbulence, viscous, or magnetic forces, or by the fluid diffusivity. Non-baryonic fluids have diffusivities larger (by factors of trillions or more) than baryonic (ordinary) fluids, and cannot condense to nucleate baryonic galaxy formation as is usually assumed. Baryonic fluids begin to condense in the plasma epoch at about 13,000 years after the big bang to form proto-superclusters, and form proto-galaxies by 300,000 years when the cooling plasma becomes neutral gas. Condensation occurs at small planetary masses to form ``primordial fog particles'' from nearly all of the primordial gas by the new theory, Gibson (1996), supporting the Schild (1996) conclusion from quasar Q0957+651A,B microlensing observations that the mass of the lens galaxy is dominated by ``rogue planets ... likely to be the missing mass''. Non-baryonic dark matter condenses on superclusters at scale L_{SD} to form massive super-halos.

  16. A fluid mechanical explanation of dark matter

    E-Print Network [OSTI]

    Gibson, C H

    1999-01-01

    Matter in the universe has become ``dark'' or ``missing'' through misconceptions about the fluid mechanics of gravitational structure formation. Gravitational condensation occurs on non-acoustic density nuclei at the largest Schwarz length scale L_{ST}, L_{SV}, L_{SM}, L_{SD} permitted by turbulence, viscous, or magnetic forces, or by the fluid diffusivity. Non-baryonic fluids have diffusivities larger (by factors of trillions or more) than baryonic (ordinary) fluids, and cannot condense to nucleate baryonic galaxy formation as is usually assumed. Baryonic fluids begin to condense in the plasma epoch at about 13,000 years after the big bang to form proto-superclusters, and form proto-galaxies by 300,000 years when the cooling plasma becomes neutral gas. Condensation occurs at small planetary masses to form ``primordial fog particles'' from nearly all of the primordial gas by the new theory, Gibson (1996), supporting the Schild (1996) conclusion from quasar Q0957+651A,B microlensing observations that the mass ...

  17. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The development of high-energy storage devices has been one in portable electronic devices, satellites, and electric vehicles. Silicon (Si) is an attractive anode

  18. CO diffusion into amorphous H2O ices

    E-Print Network [OSTI]

    Lauck, Trish; Shulenberger, Katherine; Rajappan, Mahesh; Oberg, Karin I; Cuppen, Herma M

    2015-01-01

    The mobility of atoms, molecules and radicals in icy grain mantles regulate ice restructuring, desorption, and chemistry in astrophysical environments. Interstellar ices are dominated by H2O, and diffusion on external and internal (pore) surfaces of H2O-rich ices is therefore a key process to constrain. This study aims to quantify the diffusion kinetics and barrier of the abundant ice constituent CO into H2O dominated ices at low temperatures (15-23 K), by measuring the mixing rate of initially layered H2O(:CO2)/CO ices. The mixed fraction of CO as a function of time is determined by monitoring the shape of the infrared CO stretching band. Mixing is observed at all investigated temperatures on minute time scales, and can be ascribed to CO diffusion in H2O ice pores. The diffusion coefficient and final mixed fraction depend on ice temperature, porosity, thickness and composition. The experiments are analyzed by applying Fick's diffusion equation under the assumption that mixing is due to CO diffusion into an i...

  19. Structural Mechanics & Solid Mechanics A finite element toolbox to MATLAB

    E-Print Network [OSTI]

    Ehrhardt, Matthias

    Structural Mechanics & Solid Mechanics Department of Mechanics and Materials CALFEM A finite.3 Copyright © 1999 by Structural Mechanics, LTH, Sweden. Printed by JABE Offset, Lund, Sweden. ISRN LUTVDG/TVSM--99/9001--SE (1-265) ISSN 0281-6679 Department of Mechanics and Materials Structural Mechanics #12;The

  20. Scaling laws to understand tidal dissipation in fluid planetary regions and stars I - Rotation, stratification and thermal diffusivity

    E-Print Network [OSTI]

    Auclair-Desrotour, P; Poncin-Lafitte, C Le

    2015-01-01

    Tidal dissipation in planets and stars is one of the key physical mechanisms driving the evolution of star-planet and planet-moon systems. Several signatures of its action are observed in planetary systems thanks to their orbital architecture and the rotational state of their components. Tidal dissipation inside the fluid layers of celestial bodies are intrinsically linked to the dynamics and the physical properties of the latter. This complex dependence must be characterized. We compute the tidal kinetic energy dissipated by viscous friction and thermal diffusion in a rotating local fluid Cartesian section of a star/planet/moon submitted to a periodic tidal forcing. The properties of tidal gravito-inertial waves excited by the perturbation are derived analytically as explicit functions of the tidal frequency and local fluid parameters (i.e. the rotation, the buoyancy frequency characterizing the entropy stratification, viscous and thermal diffusivities) for periodic normal modes. The sensitivity of the resul...

  1. Mechanical Engineering Department Seminar Series

    E-Print Network [OSTI]

    Awtar, Shorya

    Mechanical Engineering Department Seminar Series Mechanics of a Mosquito Professor of Mechanical Engineering Clemson University Tuesday, March 24, 2015 4:00 ­ 5:00 pm Room 1303 EECS Abstract: The mechanics of a fascicle insertion into the skin

  2. MECHANICAL ENGINEERING Program of Study

    E-Print Network [OSTI]

    Thomas, Andrew

    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

  3. Seesaw mechanism and leptogenesis

    E-Print Network [OSTI]

    D. Falcone

    2006-12-05

    A brief overview of the phenomenology related to the seesaw mechanism and the baryogenesis via leptogenesis is presented. In particular, it is explained how large but not maximal lepton mixing can be achieved within the type II seesaw mechanism. Moreover, the consequences for leptogenesis are explored, including flavor effects.

  4. Mecanica Clasica (Classical Mechanics)

    E-Print Network [OSTI]

    Rosu, H C

    1999-01-01

    First Internet undergraduate course on Classical Mechanics in Spanish (Castellano). This is about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. English and Romanian versions are in (slow) progress and hopefully will be arXived. For a similar course on Quantum Mechanics, see physics/9808031

  5. Geometrization of Quantum Mechanics

    E-Print Network [OSTI]

    J. F. Carinena; J. Clemente-Gallardo; G. Marmo

    2007-03-23

    We show that it is possible to represent various descriptions of Quantum Mechanics in geometrical terms. In particular we start with the space of observables and use the momentum map associated with the unitary group to provide an unified geometrical description for the different pictures of Quantum Mechanics. This construction provides an alternative to the usual GNS construction for pure states.

  6. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering It is a new beginning for innovative fundamental and applied and energy applications. Dr. Mark A. Tschopp is a materials engineer at the U.S. Army Research Laboratory and Mechanical Properties Mark Tschopp Materials Engineer U.S. Army Research Laboratory September 12, 2014 at 1

  7. Mechanical Systems Signal Processing

    E-Print Network [OSTI]

    Ray, Asok

    Mechanical Systems and Signal Processing Mechanical Systems and Signal Processing 21 (2007) 866 and analytical models. This paper attempts to address this inadequacy by taking advantage of advanced signal processing and pattern recognition tools. Since a vast majority of structural components that are prone

  8. Mechanical code comparator

    DOE Patents [OSTI]

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

    2002-01-01

    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.

  9. ARM: SIRS: derived, correction of downwelling shortwave diffuse hemispheric measurements using Dutton and full algorithm

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

    Laura Riihimaki

    1997-03-21

    SIRS: derived, correction of downwelling shortwave diffuse hemispheric measurements using Dutton and full algorithm

  10. Impact of axial diffusion on nitric oxide exchange in the lungs

    E-Print Network [OSTI]

    George, Steven C.

    Impact of axial diffusion on nitric oxide exchange in the lungs HYE-WON SHIN1 AND STEVEN C. GEORGE1, Hye-Won, and Steven C. George. Impact of axial diffusion on nitric oxide exchange in the lungs. J Appl of the lungs, but neglects axial diffusion. We incorporated axial diffusion into a one-dimensional trumpet

  11. 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

  12. 07SCHOOL OF MECHANICAL ENGINEERING

    E-Print Network [OSTI]

    Dimitrova, Vania

    07SCHOOL OF MECHANICAL ENGINEERING UNDERGRADUATE DEGREES School of Mechanical Engineering FACULTY OF ENGINEERING Undergraduate Degrees 2015 #12;www.engineering.leeds.ac.uk/mechanical UNDERGRADUATE DEGREES SCHOOL OF MECHANICAL ENGINEERING The School of Mechanical Engineering offers both a broad mechanical engineering degree

  13. Diffusion-controlled reactions modeling in Geant4-DNA

    SciTech Connect (OSTI)

    Karamitros, M.; Luan, S.; Bernal, M.A.; Allison, J.; Baldacchino, G.; Davidkova, M.; Francis, Z.; Friedland, W.; Ivantchenko, V.; Ivantchenko, A.; Mantero, A.; Nieminem, P.; Santin, G.; Tran, H.N.; Stepan, V.; Incerti, S.

    2014-10-01

    Context Under irradiation, a biological system undergoes a cascade of chemical reactions that can lead to an alteration of its normal operation. There are different types of radiation and many competing reactions. As a result the kinetics of chemical species is extremely complex. The simulation becomes then a powerful tool which, by describing the basic principles of chemical reactions, can reveal the dynamics of the macroscopic system. To understand the dynamics of biological systems under radiation, since the 80s there have been on-going efforts carried out by several research groups to establish a mechanistic model that consists in describing all the physical, chemical and biological phenomena following the irradiation of single cells. This approach is generally divided into a succession of stages that follow each other in time: (1) the physical stage, where the ionizing particles interact directly with the biological material; (2) the physico-chemical stage, where the targeted molecules release their energy by dissociating, creating new chemical species; (3) the chemical stage, where the new chemical species interact with each other or with the biomolecules; (4) the biological stage, where the repairing mechanisms of the cell come into play. This article focuses on the modeling of the chemical stage. Method This article presents a general method of speeding-up chemical reaction simulations in fluids based on the Smoluchowski equation and Monte-Carlo methods, where all molecules are explicitly simulated and the solvent is treated as a continuum. The model describes diffusion-controlled reactions. This method has been implemented in Geant4-DNA. The keys to the new algorithm include: (1) the combination of a method to compute time steps dynamically with a Brownian bridge process to account for chemical reactions, which avoids costly fixed time step simulations; (2) a k–d tree data structure for quickly locating, for a given molecule, its closest reactants. The performance advantage is presented in terms of complexity, and the accuracy of the new algorithm is demonstrated by simulating radiation chemistry in the context of the Geant4-DNA project. Application The time-dependent radiolytic yields of the main chemical species formed after irradiation are computed for incident protons at different energies (from 50 MeV to 500 keV). Both the time-evolution and energy dependency of the yields are discussed. The evolution, at one microsecond, of the yields of hydroxyls and solvated electrons with respect to the linear energy transfer is compared to theoretical and experimental data. According to our results, at high linear energy transfer, modeling radiation chemistry in the trading compartment representation might be adopted.

  14. Bibliography for EC'12 Tutorial: The Diffusion of Networking Techologies Sharon Goldberg Social Sciences. E. Rogers pioneering book on the social science of diffusion has seen five

    E-Print Network [OSTI]

    Goldberg, Sharon

    Bibliography for EC'12 Tutorial: The Diffusion of Networking Techologies Sharon Goldberg Background­27, 1969. 1 June 7, 2012 #12;Bibliography for EC'12 Tutorial: The Diffusion of Networking Techologies

  15. Overview of Bohmian Mechanics

    E-Print Network [OSTI]

    Xavier Oriols; Jordi Mompart

    2013-01-09

    This chapter provides a comprehensive overview of the Bohmian formulation of quantum mechanics. It starts with a historical review of the difficulties found by Louis de Broglie, David Bohm, and John S. Bell to convince the scientific community about the validity and utility of Bohmian mechanics. Then, a formal explanation of Bohmian mechanics for nonrelativistic, single-particle quantum systems is presented. The generalization to many-particle systems, where the exchange interaction and the spin play an important role, is also presented. After that, the measurement process in Bohmian mechanics is discussed. It is emphasized that Bohmian mechanics exactly reproduces the mean value and temporal and spatial correlations obtained from the standard, that is the Copenhagen or orthodox, formulation. The ontological characteristics of Bohmian mechanics provide a description of measurements as another type of interaction without the need for introducing the wave function collapse. Several solved problems are presented at the end of the chapter, giving additional mathematical support to some particular issues. A detailed description of computational algorithms to obtain Bohmian trajectories from the numerical solution of the Schrodinger or the Hamilton-Jacobi equations are presented in an appendix. The motivation of this chapter is twofold: first, as a didactic introduction to Bohmian formalism, which is used in the subsequent chapters, and second, as a self-contained summary for any newcomer interested in using Bohmian mechanics in his or her daily research activity.

  16. Pilot-Scale Benzene Retention and Release Demonstration

    SciTech Connect (OSTI)

    Marek, J.C.

    2003-11-10

    During the initial months of In-Tank Precipitation radioactive operation in 1995 the process experienced high rates of tetraphenylborate decomposition with assumed corresponding high rates of benzene generation. In March 1996 after a two month quiescent period, a water addition to Tank 48H resulted in an unexpected benzene release to the tank vapor phase. This was the first time a low energy input resulted in a significant release rate. This led to questions about how benzene, generated in-situ by TPB decomposition, was retained in the surrounding potassium tetraphenylborate slurry. It was postulated the retention mechanism may have changed during the quiescent period prior to March so the benzene present became readily releasable to the vapor phase with low energy input to the slurry or that enough benzene accumulated that some of it was in a different, more releasable form. Readily releasable is a qualitative term defined as a rapid release of benzene at a rate approaching evaporation of a free benzene layer. It is intended to distinguish between benzene in a form with high liquid phase resistance to mass transfer diffusion controlled from benzene in a form with minimal liquid phase resistance to mass transfer free benzene layer evaporation. If a readily releasable form of benzene was present, the vapor space profile during release tests was anticipated to have an initial benzene vapor space concentration peak followed by a lower vapor concentration, longer duration release.

  17. Electronic door locking mechanism

    DOE Patents [OSTI]

    Williams, G.L.; Kirby, P.G.

    1997-10-21

    The invention is a motorized linkage for engaging a thumb piece in a door mechanism. The device has an exterior lock assembly with a small battery cell and combination lock. Proper entry by a user of a security code allows the battery to operate a small motor within the exterior lock assembly. The small motor manipulates a cam-plunger which moves an actuator pin into a thumb piece. The user applies a force on to the thumb piece. This force is transmitted by the thumb piece to a latch engagement mechanism by the actuator pin. The latch engagement mechanism operates the door latch. 6 figs.

  18. Quantum Mechanics Without Observers

    E-Print Network [OSTI]

    W. H. Sulis

    2013-03-03

    The measurement problem and the role of observers have plagued quantum mechanics since its conception. Attempts to resolve these have introduced anthropomorphic or non-realist notions into physics. A shift of perspective based upon process theory and utilizing methods from combinatorial games, interpolation theory and complex systems theory results in a novel realist version of quantum mechanics incorporating quasi-local, nondeterministic hidden variables that are compatible with the no-hidden variable theorems and relativistic invariance, and reproduce the standard results of quantum mechanics to a high degree of accuracy without invoking observers.

  19. Advanced Mechanics. Mathematical Introduction

    E-Print Network [OSTI]

    G. Giachetta; L. Mangiarotti; G. Sardanashvily

    2010-01-20

    Classical non-relativistic mechanics in a general setting of time-dependent transformations and reference frame changes is formulated in the terms of fibre bundles over the time-axis R. Connections on fibre bundles are the main ingredient in this formulation of mechanics which thus is covariant under reference frame transformations. The basic notions of a non-relativistic reference frame, a relative velocity, a free motion equation, a relative acceleration, an external force are formulated. Newtonian, Lagrangian, Hamiltonian mechanical systems and the relations between them are defined. Lagrangian and Hamiltonian conservation laws are considered.

  20. Electronic door locking mechanism

    DOE Patents [OSTI]

    Williams, Gary Lin (428 E. Third Ave., Kennewick, WA 99336); Kirby, Patrick Gerald (1010 W. Fifteenth Pl., Kennewick, WA 99337)

    1997-01-01

    The invention is a motorized linkage for engaging a thumb piece in a door mechanism. The device has an exterior lock assembly with a small battery cell and combination lock. Proper entry by a user of a security code allows the battery to operate a small motor within the exterior lock assembly. The small motor manipulates a cam-plunger which moves an actuator pin into a thumb piece. The user applies a force on to the thumb piece. This force is transmitted by the thumb piece to a latch engagement mechanism by the actuator pin. The latch engagement mechanism operates the door latch.

  1. Rotary mechanical latch

    DOE Patents [OSTI]

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

    2012-11-13

    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.

  2. Test Program for High Efficiency Gas Turbine Exhaust Diffuser

    SciTech Connect (OSTI)

    Norris, Thomas R.

    2009-12-31

    This research relates to improving the efficiency of flow in a turbine exhaust, and thus, that of the turbine and power plant. The Phase I SBIR project demonstrated the technical viability of “strutlets” to control stalls on a model diffuser strut. Strutlets are a novel flow-improving vane concept intended to improve the efficiency of flow in turbine exhausts. Strutlets can help reduce turbine back pressure, and incrementally improve turbine efficiency, increase power, and reduce greenhouse gas emmission. The long-term goal is a 0.5 percent improvement of each item, averaged over the US gas turbine fleet. The strutlets were tested in a physical scale model of a gas turbine exhaust diffuser. The test flow passage is a straight, annular diffuser with three sets of struts. At the end of Phase 1, the ability of strutlets to keep flow attached to struts was demonstrated, but the strutlet drag was too high for a net efficiency advantage. An independently sponsored followup project did develop a highly-modified low-drag strutlet. In combination with other flow improving vanes, complicance to the stated goals was demonstrated for for simple cycle power plants, and to most of the goals for combined cycle power plants using this particular exhaust geometry. Importantly, low frequency diffuser noise was reduced by 5 dB or more, compared to the baseline. Appolicability to other diffuser geometries is yet to be demonstrated.

  3. Cosmic-ray diffusive reacceleration: a critical look

    E-Print Network [OSTI]

    Drury, Luke O'C

    2015-01-01

    Cosmic-ray scattering on magnetic turbulence leads to spatial diffusive propagation; if the scattering medium is moving, this will inevitably also cause changes in the momentum of the particles, so-called diffusive reacceleration. This can be described as diffusion in momentum space. Diffusive reacceleration has often been invoked to explain the peak observed in secondary-to-primary ratios at a few GeV, in particular Boron-to-Carbon. This avoids the necessity to postulate an ad-hoc break in the spatial diffusive coefficient, and has become almost a standard in modelling cosmic-ray spectra. However, at the levels invoked, the process implies a significant input of energy from the interstellar medium into cosmic rays, so that in such models interstellar space competes with the usual accelerators like supernova remnants. The questions arise: is reacceleration really occurring at the high level required to explain secondary-to-primary ratios? and are the energy requirements physically plausible? We address this i...

  4. Basic Studies of Non-Diffusive Transport in Plasmas

    SciTech Connect (OSTI)

    Morales, George J.; Maggs, James E.

    2014-10-25

    The project expanded and developed mathematical descriptions, and corresponding numerical modeling, of non-diffusive transport to incorporate new perspectives derived from basic transport experiments performed in the LAPD device at UCLA, and at fusion devices throughout the world. By non-diffusive it is meant that the transport of fundamental macroscopic parameters of a system, such as temperature and density, does not follow the standard diffusive behavior predicted by a classical Fokker-Planck equation. The appearance of non-diffusive behavior is often related to underlying microscopic processes that cause the value of a system parameter, at one spatial position, to be linked to distant events, i.e., non-locality. In the LAPD experiments the underlying process was traced to large amplitude, coherent drift-waves that give rise to chaotic trajectories. Significant advances were made in this project. The results have lead to a new perspective about the fundamentals of edge transport in magnetically confined plasmas; the insight has important consequences for worldwide studies in fusion devices. Progress was also made in advancing the mathematical techniques used to describe fractional diffusion.

  5. Methods of exploring energy diffusion in lattices with finite temperature

    E-Print Network [OSTI]

    Ping Hwang; Hong Zhao

    2011-06-15

    We discuss two methods for exploring energy diffusion in lattices with finite temperature in this paper. The first one is the energy-kick (EK) method. To apply this method, one adds an external energy kick to a particle in the lattice, and tracks its evolution by evolving the kicked system. The second one is the fluctuation-correlation (FC) method. The formula for calculating the probability density function (PDF) using the canonical ensemble is slightly revised and extended to the microcanonical ensemble. We show that the FC method has advantages over the EK method theoretically and technically. Theoretically, the PDF obtained by the FC method reveals the diffusion processes of the inner energy while the PDF obtained by the EK method represents that of the kick energy. The diffusion processes of the inner energy and the external energy added to the system, i.e., the kick energy, may be different quantitatively and even qualitatively depending on models. To show these facts, we study not only the equilibrium systems but also the stationary nonequilibrium systems. Examples showing that the inner energy and the kick energy may have different diffusion behavior are reported in both cases. The technical advantage enables us to study the long-time diffusion processes and thus avoids the finite-time effect.

  6. Lévy Fluctuations and Tracer Diffusion in Dilute Suspensions of Algae and Bacteria

    E-Print Network [OSTI]

    Irwin M. Zaid; Jörn Dunkel; Julia M. Yeomans

    2010-09-20

    Swimming microorganisms rely on effective mixing strategies to achieve efficient nutrient influx. Recent experiments, probing the mixing capability of unicellular biflagellates, revealed that passive tracer particles exhibit anomalous non-Gaussian diffusion when immersed in a dilute suspension of self-motile Chlamydomonas reinhardtii algae. Qualitatively, this observation can be explained by the fact that the algae induce a fluid flow that may occasionally accelerate the colloidal tracers to relatively large velocities. A satisfactory quantitative theory of enhanced mixing in dilute active suspensions, however, is lacking at present. In particular, it is unclear how non-Gaussian signatures in the tracers' position distribution are linked to the self-propulsion mechanism of a microorganism. Here, we develop a systematic theoretical description of anomalous tracer diffusion in active suspensions, based on a simplified tracer-swimmer interaction model that captures the typical distance scaling of a microswimmer's flow field. We show that the experimentally observed non-Gaussian tails are generic and arise due to a combination of truncated L\\'evy statistics for the velocity field and algebraically decaying time correlations in the fluid. Our analytical considerations are illustrated through extensive simulations, implemented on graphics processing units to achieve the large sample sizes required for analyzing the tails of the tracer distributions.

  7. Diffuse emission of high-energy neutrinos from gamma-ray burst fireballs

    E-Print Network [OSTI]

    Tamborra, Irene

    2015-01-01

    Gamma-ray bursts (GRBs) have been suggested as possible sources of the high-energy neutrino flux recently detected by the IceCube telescope. We revisit the fireball emission model and elaborate an analytical prescription to estimate the high-energy neutrino prompt emission from pion and kaon decays, assuming that the leading mechanism for the neutrino production is lepto-hadronic. To this purpose, we include hadronic, radiative and adiabatic cooling effects and discuss their relevance for long- (including high- and low-luminosity) and short-duration GRBs. The expected diffuse neutrino background is derived, by requiring that the GRB high-energy neutrino counterparts follow up-to-date gamma-ray luminosity functions and redshift evolutions of the long and short GRBs. Although dedicated stacking searches have been unsuccessful up to now, we find that the GRBs could contribute up to a few percents to the observed IceCube high-energy neutrino flux for sub-PeV energies, assuming that the latter has a diffuse origin...

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

    SciTech Connect (OSTI)

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

    2014-01-27

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

  9. Analysis and experimental study on formation conditions of large-scale barrier-free diffuse atmospheric pressure air plasmas in repetitive pulse mode

    SciTech Connect (OSTI)

    Li, Lee Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang

    2014-01-14

    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.

  10. Mechanical Engineering Achievement Awards 

    E-Print Network [OSTI]

    Unknown

    2011-08-17

    In this research, least-squares based finite element formulations and their applications in fluid mechanics are presented. Least-squares formulations offer several computational and theoretical advantages for Newtonian as ...

  11. Mechanics in medicine

    E-Print Network [OSTI]

    Bao, Gang

    Over decades, the theoretical and applied mechanics community has developed sophisticated approaches for analysing the behaviour of complex engineering systems. Most of these approaches have targeted systems in the ...

  12. Ultralight, ultrastiff mechanical metamaterials

    E-Print Network [OSTI]

    Zheng, Xiaoyu

    The mechanical properties of ordinary materials degrade substantially with reduced density because their structural elements bend under applied load. We report a class of microarchitected materials that maintain a nearly ...

  13. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    this chemistry in CFD codes. Finally, I will consider three different applications: ignition by a hot surface) and combustion. Guillaume Blanquart is an Assistant Professor in the Mechanical and Civil Engineering department

  14. Boosted Statistical Mechanics

    E-Print Network [OSTI]

    Massimo Testa

    2015-07-30

    Based on the fundamental principles of Relativistic Quantum Mechanics, we give a rigorous, but completely elementary, proof of the relation between fundamental observables of a statistical system when measured relatively to two inertial reference frames, connected by a Lorentz transformation.

  15. Failure mechanisms in MEMS.

    SciTech Connect (OSTI)

    Walraven, Jeremy Allen

    2003-07-01

    MEMS components by their very nature have different and unique failure mechanisms than their macroscopic counterparts. This paper discusses failure mechanisms observed in various MEMS components and technologies. MEMS devices fabricated using bulk and surface micromachining process technologies are emphasized. MEMS devices offer uniqueness in their application, fabrication, and functionality. Their uniqueness creates various failure mechanisms not typically found in their bulk or IC counterparts. In ICs, electrical precautions are taken to mitigate failure. In MEMS, both electrical and mechanical precautions must be enacted to reduce the risk of failure and increased reliability. Unlike ICs, many MEMS components are designed to interact with their environment, making the fabrication, testing, and packaging processes critical for the success of the device.

  16. Renewable Auction Mechanism (RAM)

    Broader source: Energy.gov [DOE]

    The Renewable Auction Mechanism (RAM), approved by the California Public Utilities Commission (CPUC) in December 2010, is expected to result in 1,299 megawatts (MW) of new distributed generation ...

  17. Time in quantum mechanics 

    E-Print Network [OSTI]

    Chapin, Kimberly R.

    1997-01-01

    TIME IN QUANTUM MECHANICS A Thesis by KIMBERLY R. CHAPIN Submitted to Texas A8M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style and content by: Marian O. Scully (Chair... of Committee) Edward S. Fry (Member) aan Laane (Member) Thomas W. Adair, III (Head of Department) August 1997 Major Subject: Physics TIME IN QIJANTUM MECHANICS A Thesis by KIMBERLY R. CHAPIN Submitted to the Oflice of Graduate Studies of Texas A...

  18. Phase Field Fracture Mechanics.

    SciTech Connect (OSTI)

    Robertson, Brett Anthony

    2015-11-01

    For this assignment, a newer technique of fracture mechanics using a phase field approach, will be examined and compared with experimental data for a bend test and a tension test. The software being used is Sierra Solid Mechanics, an implicit/explicit finite element code developed at Sandia National Labs in Albuquerque, New Mexico. The bend test experimental data was also obtained at Sandia Labs while the tension test data was found in a report online from Purdue University.

  19. 126 MECHANICAL ENGINEERING Department of Mechanical Engineering (MEE)

    E-Print Network [OSTI]

    Kostic, Milivoje M.

    126 MECHANICAL ENGINEERING Department of Mechanical Engineering (MEE) Acting Chair: Kyuil Kim professor, Ph.D., P.E., University of Dayton Master of Science in Mechanical Engineering The Department of Mechanical Engineering offers a program leading to the M.S. in mechanical engineering. The program

  20. Mechanical Engineering Is Mechanical Engineering right for me?

    E-Print Network [OSTI]

    Martin, Ralph R.

    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