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Sample records for defects mechanical behavior

  1. Effect of point and grain boundary defects on the mechanical behavior of monolayer MoS{sub 2} under tension via atomistic simulations

    SciTech Connect (OSTI)

    Dang, Khanh Q. [Department of Mechanical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Spearot, Douglas E., E-mail: dspearot@uark.edu [Department of Mechanical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

    2014-07-07

    Atomistic simulation is used to study the structure and energy of defects in monolayer MoS{sub 2} and the role of defects on the mechanical properties of monolayer MoS{sub 2}. First, energy minimization is used to study the structure and energy of monosulfur vacancies positioned within the bottom S layer of the MoS{sub 2} lattice, and 60° symmetric tilt grain boundaries along the zigzag and armchair directions, with comparison to experimental observations and density functional theory calculations. Second, molecular dynamics simulations are used to subject suspended defect-containing MoS{sub 2} membranes to a state of multiaxial tension. A phase transformation is observed in the defect-containing membranes, similar to prior work in the literature. For monolayer MoS{sub 2} membranes with point defects, groups of monosulfur vacancies promote stress-concentration points, allowing failure to initiate away from the center of the membrane. For monolayer MoS{sub 2} membranes with grain boundaries, failure initiates at the grain boundary and it is found that the breaking force for the membrane is independent of grain boundary energy.

  2. Mechanical Behavior of Indium Nanostructures

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

    Mechanical Behavior of Indium Nanostructures Mechanical Behavior of Indium Nanostructures Print Wednesday, 26 May 2010 00:00 Indium is a key material in lead-free solder...

  3. Defect behavior of polycrystalline solar cell silicon

    SciTech Connect (OSTI)

    Schroder, D.K.; Park, S.H.; Hwang, I.G.; Mohr, J.B.; Hanly, M.P.

    1993-05-01

    The major objective of this study, conducted from October 1988 to September 1991, was to gain an understanding of the behavior of impurities in polycrystalline silicon and the influence of these impurities on solar cell efficiency. The authors studied edge-defined film-fed growth (EFG) and cast poly-Si materials and solar cells. With EFG Si they concentrated on chromium-doped materials and cells to determine the role of Cr on solar cell performance. Cast poly-Si samples were not deliberately contaminated. Samples were characterized by cell efficiency, current-voltage, deep-level transient spectroscopy (DLTS), surface photovoltage (SPV), open-circuit voltage decay, secondary ion mass spectrometry, and Fourier transform infrared spectroscopy measurements. They find that Cr forms Cr-B pairs with boron at room temperature and these pairs dissociate into Cr{sub i}{sup +} and B{sup {minus}} during anneals at 210{degrees}C for 10 min. Following the anneal, Cr-B pairs reform at room temperature with a time constant of 230 h. Chromium forms CrSi{sub 2} precipitates in heavily contaminated regions and they find evidence of CrSi{sub 2} gettering, but a lack of chromium segregation or precipitation to grain boundaries and dislocations. Cr-B pairs have well defined DLTS peaks. However, DLTS spectra of other defects are not well defined, giving broad peaks indicative of defects with a range of energy levels in the band gap. In some high-stress, low-efficiency cast poly-Si they detect SiC precipitates, but not in low-stress, high-efficiency samples. SPV measurements result in nonlinear SPV curves in some materials that are likely due to varying optical absorption coefficients due to locally varying stress in the material.

  4. Mechanical Behavior of Indium Nanostructures

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

    Mechanical Behavior of Indium Nanostructures Print Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended...

  5. Mechanical properties of carbon nanotubes with vacancies and related defects M. Sammalkorpi,1,

    E-Print Network [OSTI]

    Nordlund, Kai

    mechanical characteris- tics. Likewise, defects may enhance the overall characteris- tics of bundles

  6. Mechanical Behavior of Indium Nanostructures

    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 wouldMass map shines light on dark matter By SarahMODELING CLOUD1Mechanical BehaviorMechanical

  7. Mechanical Behavior of Indium Nanostructures

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse BergkampCentermillion Measurement of Muon Neutrino andMechanical Behavior

  8. Mechanical Behavior of Indium Nanostructures

    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 wouldMass map shines light on dark matter By SarahMODELING CLOUD1Mechanical Behavior of Indium

  9. Mechanical Behavior of Indium Nanostructures

    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 wouldMass map shines light on dark matter By SarahMODELING CLOUD1Mechanical Behavior of

  10. Mechanical Behavior of Indium Nanostructures

    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 wouldMass map shines light on dark matter By SarahMODELING CLOUD1Mechanical Behavior

  11. Defect-related internal dissipation in mechanical resonators and the study of coupled mechanical systems.

    SciTech Connect (OSTI)

    Friedmann, Thomas Aquinas; Czaplewski, David A.; Sullivan, John Patrick; Modine, Normand Arthur; Wendt, Joel Robert; Aslam, Dean (Michigan State University, Lansing, MI); Sepulveda-Alancastro, Nelson (University of Puerto Rico, Mayaguez, PR)

    2007-01-01

    Understanding internal dissipation in resonant mechanical systems at the micro- and nanoscale is of great technological and fundamental interest. Resonant mechanical systems are central to many sensor technologies, and microscale resonators form the basis of a variety of scanning probe microscopies. Furthermore, coupled resonant mechanical systems are of great utility for the study of complex dynamics in systems ranging from biology to electronics to photonics. In this work, we report the detailed experimental study of internal dissipation in micro- and nanomechanical oscillators fabricated from amorphous and crystalline diamond materials, atomistic modeling of dissipation in amorphous, defect-free, and defect-containing crystalline silicon, and experimental work on the properties of one-dimensional and two-dimensional coupled mechanical oscillator arrays. We have identified that internal dissipation in most micro- and nanoscale oscillators is limited by defect relaxation processes, with large differences in the nature of the defects as the local order of the material ranges from amorphous to crystalline. Atomistic simulations also showed a dominant role of defect relaxation processes in controlling internal dissipation. Our studies of one-dimensional and two-dimensional coupled oscillator arrays revealed that it is possible to create mechanical systems that should be ideal for the study of non-linear dynamics and localization.

  12. Influence of oriented topological defects on the mechanical properties of carbon nanotube heterojunctions

    SciTech Connect (OSTI)

    Lee, We-Jay [National Center for High-Performance Computing; Chang, Jee-Gong [National Center for High-Performance Computing; Yang, An-Cheng [National Center for High-Performance Computing; Wang, Yeng-Tseng [National Center for High-Performance Computing; Su, Wan-Sheng [National Center for High-Performance Computing; Wang, Cai-Zhuang [Ames Laboratory; Ho, Kai-Ming [Ames Laboratory

    2013-10-10

    The mechanical properties of finite-length (5,0)/(8,0) single-walled carbon nanotube (SWCNT) heterojunctions with manipulated topological defects are investigated using molecular dynamics simulation calculations. The results show that the mechanical properties and deformation behavior of SWCNT heterojunctions are mainly affected not only by the diameter of the thinner segment of the SWCNT heterojunction but also by the orientation of the heptagon-heptagon (7-7) pair in the junction region. Moreover, the orientation of the 7-7 pair strongly affects those properties in the compression loading than those in tensile loading. Finally, it is found that the location of buckling deformation in the heterojunctions is dependent on the orientation of the 7-7 pair in the compression.

  13. Mechanical Behavior of Indium Nanostructures

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

    to develop a fundamental understanding of this material's small-scale mechanical properties and reliability. Researchers from the University of Waterloo, California...

  14. Improving Cooling performance of the mechanical resonator with the two-level-system defects

    E-Print Network [OSTI]

    Tian Chen; Xiang-Bin Wang

    2014-06-03

    We study cooling performance of a realistic mechanical resonator containing defects. The normal cooling method through an optomechanical system does not work efficiently due to those defects. We show by employing periodical $\\sigma_z$ pulses, we can eliminate the interaction between defects and their surrounded heat baths up to the first order of time. Compared with the cooling performance of no $\\sigma_z$ pulses case, much better cooling results are obtained. Moreover, this pulse sequence has an ability to improve the cooling performance of the resonator with different defects energy gaps and different defects damping rates.

  15. Influence of defects on thermal and mechanical properties of metals 

    E-Print Network [OSTI]

    Kamani, Sandeep Kumar

    2009-05-15

    ) and surface defects (grain boundary) using molecular dynamics simulations. Constant stress-constant temperature ensemble with atmospheric pressures is employed. Various properties like average volume, density, potential energy and total energy are obtained...

  16. Characterization of Thermo-Mechanical Behaviors of Advanced High...

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

    Thermo-Mechanical Behaviors of Advanced High Strength Steels (AHSS) Characterization of Thermo-Mechanical Behaviors of Advanced High Strength Steels (AHSS) 2009 DOE Hydrogen...

  17. Thermal-hydrologic-mechanical behavior of single fractures in...

    Office of Scientific and Technical Information (OSTI)

    Thermal-hydrologic-mechanical behavior of single fractures in EGS reservoirs Citation Details In-Document Search Title: Thermal-hydrologic-mechanical behavior of single fractures...

  18. Mechanical Behavior of Indium Nanostructures

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse BergkampCentermillion Measurement of Muon Neutrino andMechanical

  19. Mechanical Behavior of Indium Nanostructures

    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 wouldMass map shines light on dark matter By SarahMODELING CLOUD1Mechanical

  20. PAH Sorption Mechanism and Partitioning Behavior in

    E-Print Network [OSTI]

    Zare, Richard N.

    of crude oil at high temperatures in the gas-making operation and is coated or impregnated with oil of oil at high temperatures. Lampblack Production. Lampblack and tar were byprod- ucts of the oilPAH Sorption Mechanism and Partitioning Behavior in Lampblack-Impacted Soils from Former Oil

  1. Hydrogen Segregation in Palladium and the Combined Effects of Temperature and Defects on Mechanical Properties

    E-Print Network [OSTI]

    Pham, Hieu H; Cagin, Tahir

    2015-01-01

    Atomistic calculations were carried out to investigate the mechanical properties of Pd crystals as a combined function of structural defects, hydrogen concentration and high temperature. These factors are found to individually induce degradation in the mechanical strength of Pd in a monotonous manner. In addition, defects such as vacancies and grain boundaries could provide a driving force for hydrogen segregation, thus enhance the tendency for their trapping. The simulations show that hydrogen maintains the highest localization at grain boundaries at ambient temperatures. This finding correlates well with the experimental observation that hydrogen embrittlement is more frequently observed around room temperature. The strength-limiting mechanism of mechanical failures induced by hydrogen is also discussed, which supports the hydrogen-enhanced localized plasticity theorem.

  2. The Defect Energies and Deformation Mechanisms of Single Crystal Superalloys

    E-Print Network [OSTI]

    Hillier, Graham Stewart

    1985-01-29

    Element Nimonic 75 Nimonic 80 A Mar-M 002 Mar-M 200 SRR 99 Ni 76.0 70.7 60.5 59.5 66.5 Ai 2.7 12.2 11.2 12.1 Ti 0.5 2.9 1.9 2.5 2.7 Cr 21.8 20.8 10.2 10.4 9.7 Co 1.1 10.0 10.2 4.6 W 3.2 4.1 3.0 Ta 0.8 0.9 Nb 0.7 Mn 0.1 0.1 Si 1.4 1.4 C 0.3 0.3 0.7 0.7 <0... MECHANISMS OF SINGLE CRYSTAL SUPERALLOYS by Graham Stewart Hillier, B.Met. st. John's College Cambridge A dissertation submitted for the degree. of Philosophiae Doctor at the University of Cambridge September 1984 Dedicated to my Mum and Dad PREFACE...

  3. Nonradiative coherent carrier captures and defect reaction at deep-level defects via phonon-kick mechanism

    SciTech Connect (OSTI)

    Wakita, Masaki; Suzuki, Kei; Shinozuka, Yuzo

    2014-02-21

    We simulated the time evolution of electron-lattice coupling mode, and a series of nonradiative carrier captures by a deep-level defect in a semiconductor. For lattice relaxation energy of the order of the band gap, a series of coherent (athermal) electron and hole captures by a defect is possible for high carrier densities, which results in an inflation in the induced lattice vibration, which in turn enhances a defect reaction.

  4. A study of the mechanism of laser welding defects in low thermal expansion superalloy GH909

    SciTech Connect (OSTI)

    Yan, Fei; Wang, Chunming, E-mail: yanxiangfei225@163.com; Wang, Yajun; Hu, Xiyuan; Wang, Tianjiao; Li, Jianmin; Li, Guozhu

    2013-04-15

    In this paper, we describe experimental laser welding of low-thermal-expansion superalloy GH909. The main welding defects of GH909 by laser in the weld are liquation cracks and porosities, including hydrogen and carbon monoxide porosity. The forming mechanism of laser welding defects was investigated. This investigation was conducted using an optical microscope, scanning electron microscope, energy diffraction spectrum, X-ray diffractometer and other methodologies. The results demonstrated that porosities appearing in the central weld were related to incomplete removal of oxide film on the surface of the welding samples. The porosities produced by these bubbles were formed as a result of residual hydrogen or oxygenium in the weld. These elements failed to escape from the weld since laser welding has both a rapid welding speed and cooling rate. The emerging crack in the heat affected zone is a liquation crack and extends along the grain boundary as a result of composition segregation. Laves–Ni{sub 2}Ti phase with low melting point is a harmful phase, and the stress causes grain boundaries to liquefy, migrate and even crack. Removing the oxides on the surface of the samples before welding and carefully controlling technological parameters can reduce welding defects and improve formation of the GH909 alloy weld. - Highlights: ? It is a new process for the forming of GH909 alloy via laser welding. ? The forming mechanism of laser welding defects in GH909 has been studied. ? It may be a means to improve the efficiency of aircraft engine production.

  5. Behavior analysis and mechanism: One is not the other

    E-Print Network [OSTI]

    Morris, Edward K.

    1993-01-01

    Behavior analysts have been called mechanists, and behavior analysis is said to be mechanistic, that is, aligned with the philosophy of mechanism. What this means is analyzed by (1) examining standard and specialized dictionary and encyclopedia...

  6. Mechanical Behaviors of Alloys From First Principles

    E-Print Network [OSTI]

    Hanlumyuang, Yuranan

    2011-01-01

    Some Backgrounds on The Quantum Mechanical Stresses . . .3.2.2 The Quantum Mechanical Stresses and The Generalized3.2.3 Quantum-Mechanical

  7. Characterization of Thermo-Mechanical Behaviors of Advanced High...

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

    AHHS) Characterization of Thermo-Mechanical Behaviors of Advanced High Strength Steels (AHHS) Presentation from the U.S. DOE Office of Vehicle Technologies "Mega" Merit Review 2008...

  8. Structure and mechanical behavior of bird beaks

    E-Print Network [OSTI]

    Seki, Yasuaki

    2009-01-01

    2.1.1 Structure and Mechanical Properties 2.2 Biomimetic2.3.3 Mechanical Properties of Keratins . . 2.3.4 Mammalian2.4.2 Mechanical Properties of Foams . . . . . . . . . .

  9. Model for Electron-Beam-Induced Current Analysis of mc-Si Addressing Defect Contrast Behavior in Heavily Contaminated PV Material: Preprint

    SciTech Connect (OSTI)

    Guthrey, H.; Gorman, B.; Al-Jassim, M.

    2012-06-01

    Much work has been done to correlate electron-beam-induced current (EBIC) contrast behavior of extended defects with the character and degree of impurity decoration. However, existing models fail to account for recently observed contrast behavior of defects in heavily contaminated mc-Si PV cells. We have observed large increases in defect contrast with decreasing temperature for all electrically active defects, regardless of their initial contrast signatures at ambient temperature. This negates the usefulness of the existing models in identifying defect character and levels of impurity decoration based on the temperature dependence of the contrast behavior. By considering the interactions of transition metal impurities with the silicon lattice and extended defects, we attempt to provide an explanation for these observations. Our findings will enhance the ability of the PV community to understand and mitigate the effects of these types of defects as the adoption of increasingly lower purity feedstocks for mc-Si PV production continues.

  10. Mechanical properties and tribological behavior of contaminate...

    Office of Scientific and Technical Information (OSTI)

    AND MISCELLANEOUSMATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; MECHANICAL PROPERTIES; TRIBOLOGY; PARTICULATES; NANOSTRUCTURES; IMPURITIES; MACHINE PARTS; MINIATURIZATION...

  11. Graphene flakes with defective edge terminations: Universal and topological aspects, and one-dimensional quantum behavior

    E-Print Network [OSTI]

    Igor Romanovsky; Constantine Yannouleas; Uzi Landman

    2012-10-17

    Systematic tight-binding investigations of the electronic spectra (as a function of the magnetic field) are presented for trigonal graphene nanoflakes with reconstructed zigzag edges, where a succession of pentagons and heptagons, that is 5-7 defects, replaces the hexagons at the zigzag edge. For nanoflakes with such reczag defective edges, emphasis is placed on topological aspects and connections underlying the patterns dominating these spectra. The electronic spectra of trigonal graphene nanoflakes with reczag edge terminations exhibit certain unique features, in addition to those that are well known to appear for graphene dots with zigzag edge termination. These unique features include breaking of the particle-hole symmetry, and they are associated with nonlinear dispersion of the energy as a function of momentum, which may be interpreted as nonrelativistic behavior. The general topological features shared with the zigzag flakes include the appearance of energy gaps at zero and low magnetic fields due to finite size, the formation of relativistic Landau levels at high magnetic fields, and the presence between the Landau levels of edge states (the socalled Halperin states) associated with the integer quantum Hall effect. Topological regimes, unique to the reczag nanoflakes, appear within a stripe of negative energies E_b < E < 0, and along a separate feature forming a constant-energy line outside this stripe. The lower bound (E_b) specifying the energy stripe is independent of size. A main finding concerns the limited applicability of the continuous Dirac-Weyl equation, since the latter does not reproduce the special reczag features. (See also the extended abstract in the paper.)

  12. Mechanical behavior of dip-brazed aluminum sandwich panels

    E-Print Network [OSTI]

    Hohmann, Brian P. (Brian Patrick)

    2007-01-01

    An experimental study was carried out to determine the mechanical behavior of sandwich panels containing cellular cores of varying shape. Compression and four point bend tests were performed on sandwich panels with square ...

  13. Nanostructure stabilization and mechanical behavior of binary nanocrystalline alloys

    E-Print Network [OSTI]

    Trelewicz, Jason R

    2009-01-01

    The unique mechanical behavior of nanocrystalline metals has become of great interest in recent years, owing to both their remarkable strength and the emergence of new deformation physics at the nanoscale. Of particular ...

  14. Mechanical behavior of elastic rods under constraint

    E-Print Network [OSTI]

    Miller, James Thomas, Ph. D. Massachusetts Institute of Technology

    2014-01-01

    We present the results of an experimental investigation of the mechanics of thin elastic rods under a variety of loading conditions. Four scenarios are explored, with increasing complexity: i) the shape of a naturally ...

  15. Transport-reaction model for defect and carrier behavior within displacement cascades in gallium arsenide

    SciTech Connect (OSTI)

    Wampler, William R.; Myers, Samuel M.

    2014-02-01

    A model is presented for recombination of charge carriers at displacement damage in gallium arsenide, which includes clustering of the defects in atomic displacement cascades produced by neutron or ion irradiation. The carrier recombination model is based on an atomistic description of capture and emission of carriers by the defects with time evolution resulting from the migration and reaction of the defects. The physics and equations on which the model is based are presented, along with details of the numerical methods used for their solution. The model uses a continuum description of diffusion, field-drift and reaction of carriers and defects within a representative spherically symmetric cluster. The initial radial defect profiles within the cluster were chosen through pair-correlation-function analysis of the spatial distribution of defects obtained from the binary-collision code MARLOWE, using recoil energies for fission neutrons. Charging of the defects can produce high electric fields within the cluster which may influence transport and reaction of carriers and defects, and which may enhance carrier recombination through band-to-trap tunneling. Properties of the defects are discussed and values for their parameters are given, many of which were obtained from density functional theory. The model provides a basis for predicting the transient response of III-V heterojunction bipolar transistors to pulsed neutron irradiation.

  16. Taurine protects methamphetamine-induced developmental angiogenesis defect through antioxidant mechanism

    SciTech Connect (OSTI)

    Shao, Xue; Hu, Zhengtao; Hu, Chunyan; Bu, Qian; Yan, Guangyan [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China)] [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China); Deng, Pengchi [Analytical and Testing Center, Sichuan University, Chengdu 610041 (China)] [Analytical and Testing Center, Sichuan University, Chengdu 610041 (China); Lv, Lei [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China)] [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China); Wu, Dan [College of Basic and Forensic Medicine, Sichuan University, Chengdu 610041 (China)] [College of Basic and Forensic Medicine, Sichuan University, Chengdu 610041 (China); Deng, Yi; Zhao, Jinxuan; Zhu, Ruiming; Li, Yan; Li, Hongyu; Xu, Youzhi; Yang, Hanshuo; Zhao, Yinglan [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China)] [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China); Cen, Xiaobo, E-mail: xbcenalan@vip.sina.com [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China)] [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China)

    2012-05-01

    Investigations have characterized addictive drug-induced developmental cardiovascular malformation in human, non-human primate and rodent. However, the underlying mechanism of malformation caused by drugs during pregnancy is still largely unknown, and preventive and therapeutic measures have been lacking. Using {sup 1}H NMR spectroscopy, we profiled the metabolites from human embryo endothelial cells exposed to methamphetamine (METH) and quantified a total of 226 peaks. We identified 11 metabolites modified robustly and found that taurine markedly increased. We then validated the hypothesis that this dramatic increase in taurine could attribute to its effect in inhibiting METH-induced developmental angiogenesis defect. Taurine supplement showed a more significant potential than other metabolites in protecting against METH-induced injury in endothelial cells. Taurine strongly attenuated METH-induced inhibition of proliferation and migration in endothelial cells. Furthermore, death rate and vessel abnormality of zebrafish embryos treated with METH were greatly reversed by taurine. In addition, taurine supplement caused a rapid decrease in reactive oxygen species generation and strongly attenuated the excitable arise of antioxidase activities in the beginning of METH exposure prophase. Dysregulations of NF-?B, p-ERK as well as Bax, which reflect apoptosis, cell cycle arrest and oxidative stress in vascular endothelium, were blocked by taurine. Our results provide the first evidence that taurine prevents METH-caused developmental angiogenesis defect through antioxidant mechanism. Taurine could serve as a potential therapeutic or preventive intervention of developmental vascular malformation for the pregnant women with drug use. Highlights: ? Metabonomics findings. ? Abnormal development. ? Dysregulations of key proteins.

  17. Graphene flakes with defective edge terminations: Universal and topological aspects, and one-dimensional quantum behavior

    E-Print Network [OSTI]

    Yannouleas, Constantine

    Graphene flakes with defective edge terminations: Universal and topological aspects, and one graphene nanoflakes with reconstructed zigzag edges, where a succes- sion of pentagons and heptagons these spectra. The electronic spectra of trigonal graphene nanoflakes with reczag edge terminations exhibit

  18. Determining mechanical behavior of solid materials using miniature specimens

    DOE Patents [OSTI]

    Manahan, M.P.; Argon, A.S.; Harling, O.K.

    1986-02-04

    A Miniaturized Bend Test (MBT) capable of extracting and determining mechanical behavior information from specimens only so large as to have at least a volume or smallest dimension sufficient to satisfy continuum behavior in all directions is disclosed. The mechanical behavior of the material is determined from the measurements taken during the bending of the specimen and is processed according to the principles of linear or nonlinear material mechanics or both. In a preferred embodiment the determination is carried out by a code which is constructed according to the finite element method, and the specimen used for the determinations is a miniature disk simply supported for central loading at the axis on the center of the disk. 51 figs.

  19. Determining mechanical behavior of solid materials using miniature specimens

    DOE Patents [OSTI]

    Manahan, Michael P. (Columbus, OH); Argon, Ali S. (Belmont, MA); Harling, Otto K. (Hingham, MA)

    1986-01-01

    A Miniaturized Bend Test (MBT) capable of extracting and determining mechanical behavior information from specimens only so large as to have at least a volume or smallest dimension sufficient to satisfy continuum behavior in all directions. The mechanical behavior of the material is determined from the measurements taken during the bending of the specimen and is processed according to the principles of linear or nonlinear material mechanics or both. In a preferred embodiment the determination is carried out by a code which is constructed according to the finite element method, and the specimen used for the determinations is a miniature disk simply supported for central loading at the axis on the center of the disk.

  20. Biomaterials 26 (2005) 46954706 Viscoelastic and mechanical behavior of recombinant

    E-Print Network [OSTI]

    Srinivasarao, Mohan

    2005-01-01

    Biomaterials 26 (2005) 4695­4706 Viscoelastic and mechanical behavior of recombinant protein of an Ala for the consensus Gly ARTICLE IN PRESS www.elsevier.com/locate/biomaterials 0142-9612/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.biomaterials.2004

  1. Mechanism and contextualism in behavior analysis: Just some observations

    E-Print Network [OSTI]

    Morris, Edward K.

    1993-01-01

    Responds to peer commentary on his original article (see record 1993-39723-001) on behavior analysis and mechanism written by D. E. Blackman, R. L. Shull and P. S. Lawrence, and J. E. Staddon (see PA, Vols 23849, 23861, and 23862, respectively...

  2. Impact of defects on the electrical transport, optical properties and failure mechanisms of GaN nanowires.

    SciTech Connect (OSTI)

    Armstrong, Andrew M.; Aubry, Sylvie; Shaner, Eric Arthur; Siegal, Michael P.; Li, Qiming; Jones, Reese E.; Westover, Tyler; Wang, George T.; Zhou, Xiao Wang; Talin, Albert Alec; Bogart, Katherine Huderle Andersen; Harris, C. Thomas; Huang, Jian Yu

    2010-09-01

    We present the results of a three year LDRD project that focused on understanding the impact of defects on the electrical, optical and thermal properties of GaN-based nanowires (NWs). We describe the development and application of a host of experimental techniques to quantify and understand the physics of defects and thermal transport in GaN NWs. We also present the development of analytical models and computational studies of thermal conductivity in GaN NWs. Finally, we present an atomistic model for GaN NW electrical breakdown supported with experimental evidence. GaN-based nanowires are attractive for applications requiring compact, high-current density devices such as ultraviolet laser arrays. Understanding GaN nanowire failure at high-current density is crucial to developing nanowire (NW) devices. Nanowire device failure is likely more complex than thin film due to the prominence of surface effects and enhanced interaction among point defects. Understanding the impact of surfaces and point defects on nanowire thermal and electrical transport is the first step toward rational control and mitigation of device failure mechanisms. However, investigating defects in GaN NWs is extremely challenging because conventional defect spectroscopy techniques are unsuitable for wide-bandgap nanostructures. To understand NW breakdown, the influence of pre-existing and emergent defects during high current stress on NW properties will be investigated. Acute sensitivity of NW thermal conductivity to point-defect density is expected due to the lack of threading dislocation (TD) gettering sites, and enhanced phonon-surface scattering further inhibits thermal transport. Excess defect creation during Joule heating could further degrade thermal conductivity, producing a viscous cycle culminating in catastrophic breakdown. To investigate these issues, a unique combination of electron microscopy, scanning luminescence and photoconductivity implemented at the nanoscale will be used in concert with sophisticated molecular-dynamics calculations of surface and defect-mediated NW thermal transport. This proposal seeks to elucidate long standing material science questions for GaN while addressing issues critical to realizing reliable GaN NW devices.

  3. Dynamic behavior of Ni80Fe20 nanowires with controlled defects V. E. Demidov,2

    E-Print Network [OSTI]

    Demokritov, S.O.

    . Cottam,3 S. O. Demokritov,2,4 and A. O. Adeyeye1,a) 1 Information Storage Materials Laboratory due to their potential applica- tion for microwave devices1 and domain wall logic devices.2 Coupled the studies for the dynamic properties of NWs assume that there are no defects on the nanostructures. However

  4. 2010 Thin Film & Small Scale Mechanical Behavior Gordon Research Conference

    SciTech Connect (OSTI)

    Dr. Thomas Balk

    2010-07-30

    Over the past decades, it has been well established that the mechanical behavior of materials changes when they are confined geometrically at least in one dimension to small scale. It is the aim of the 2010 Gordon Conference on 'Thin Film and Small Scale Mechanical Behavior' to discuss cutting-edge research on elastic, plastic and time-dependent deformation as well as degradation mechanisms like fracture, fatigue and wear at small scales. As in the past, the conference will benefit from contributions from fundamental studies of physical mechanisms linked to material science and engineering reaching towards application in modern applications ranging from optical and microelectronic devices and nano- or micro-electrical mechanical systems to devices for energy production and storage. The conference will feature entirely new testing methodologies and in situ measurements as well as recent progress in atomistic and micromechanical modeling. Particularly, emerging topics in the area of energy conversion and storage, such as material for batteries will be highlighted. The study of small-scale mechanical phenomena in systems related to energy production, conversion or storage offer an enticing opportunity to materials scientists, who can provide new insight and investigate these phenomena with methods that have not previously been exploited.

  5. ENG ME 582/ MS 582 Mechanical Behavior of Materials Prof. T.W. Murray ME 582/ MS 582 Mechanical Behavior of Materials

    E-Print Network [OSTI]

    Lin, Xi

    ENG ME 582/ MS 582 Mechanical Behavior of Materials Prof. T.W. Murray ME 582/ MS 582 Mechanical are Structural Mechanics (ENG ME309 or equivalent) and Engineering Mathematics (EMG ME400 or equivalent on Courseinfo. Recommended Text: T.H. Courtney, Mechanical Behavior of Materials (2nd Edition), Waveland Press

  6. Configuration of ripple domains and their topological defects formed under local mechanical stress on hexagonal monolayer graphene

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

    Park, Yeonggu; Choi, Jin Sik; Choi, Taekjib; Lee, Mi Jung; Jia, Quanxi; Park, Minwoo; Lee, Hoonkyung; Park, Bae Ho

    2015-03-24

    Ripples in graphene are extensively investigated because they ensure the mechanical stability of two-dimensional graphene and affect its electronic properties. They arise from spontaneous symmetry breaking and are usually manifested in the form of domains with long-range order. It is expected that topological defects accompany a material exhibiting long-range order, whose functionality depends on characteristics of domains and topological defects. However, there remains a lack of understanding regarding ripple domains and their topological defects formed on monolayer graphene. Here we explore configuration of ripple domains and their topological defects in exfoliated monolayer graphenes on SiO?/Si substrates using transverse shear microscope.more »We observe three-color domains with three different ripple directions, which meet at a core. Furthermore, the closed domain is surrounded by an even number of cores connected together by domain boundaries, similar to topological vortex and anti-vortex pairs. In addition, we have found that axisymmetric three-color domains can be induced around nanoparticles underneath the graphene. This fascinating configuration of ripple domains may result from the intrinsic hexagonal symmetry of two-dimensional graphene, which is supported by theoretical simulation using molecular dynamics. Our findings are expected to play a key role in understanding of ripple physics in graphene and other two-dimensional materials.« less

  7. Corrosion and mechanical behavior of materials for coal gasification applications

    SciTech Connect (OSTI)

    Natesan, K.

    1980-05-01

    A state-of-the-art review is presented on the corrosion and mechanical behavior of materials at elevated temperatures in coal-gasification environments. The gas atmosphere in coal-conversion processes are, in general, complex mixtures which contain sulfur-bearing components (H/sub 2/S, SO/sub 2/, and COS) as well as oxidants (CO/sub 2//CO and H/sub 2/O/H/sub 2/). The information developed over the last five years clearly shows sulfidation to be the major mode of material degradation in these environments. The corrosion behavior of structural materials in complex gas environments is examined to evaluate the interrelationships between gas chemistry, alloy chemistry, temperature, and pressure. Thermodynamic aspects of high-temperature corrosion processes that pertain to coal conversion are discussed, and kinetic data are used to compare the behavior of different commercial materials of interest. The influence of complex gas environments on the mechanical properties such as tensile, stress-rupture, and impact on selected alloys is presented. The data have been analyzed, wherever possible, to examine the role of environment on the property variation. The results from ongoing programs on char effects on corrosion and on alloy protection via coatings, cladding, and weld overlay are presented. Areas of additional research with particular emphasis on the development of a better understanding of corrosion processes in complex environments and on alloy design for improved corrosion resistance are discussed. 54 references, 65 figures, 24 tables.

  8. Overexpressed of RAD51 suppresses recombination defects: a possible mechanism to reverse genomic instability

    SciTech Connect (OSTI)

    Schild, David; Wiese, Claudia

    2009-10-15

    RAD51, a key protein in the homologous recombinational DNA repair (HRR) pathway, is the major strand-transferase required for mitotic recombination. An important early step in HRR is the formation of single-stranded DNA (ss-DNA) coated by RPA (a ss-DNA binding protein). Displacement of RPA by RAD51 is highly regulated and facilitated by a number of different proteins known as the 'recombination mediators'. To assist these recombination mediators, a second group of proteins also is required and we are defining these proteins here as 'recombination co-mediators'. Defects in either recombination mediators or comediators, including BRCA1 and BRCA2, lead to impaired HRR that can genetically be complemented for (i.e. suppressed) by overexpression of RAD51. Defects in HRR have long been known to contribute to genomic instability leading to tumor development. Since genomic instability also slows cell growth, precancerous cells presumably require genomic restabilization to gain a growth advantage. RAD51 is overexpressed in many tumors, and therefore, we hypothesize that the complementing ability of elevated levels of RAD51 in tumors with initial HRR defects limits genomic instability during carcinogenic progression. Of particular interest, this model may also help explain the high frequency of TP53 mutations in human cancers, since wild-type p53 represses RAD51.

  9. Reservoir interactions during Bose-Einstein condensation: modified critical scaling in the Kibble-Zurek mechanism of defect formation

    E-Print Network [OSTI]

    R. G. McDonald; A. S. Bradley

    2015-07-30

    As a test of the Kibble-Zurek mechanism (KZM) of defect formation, we simulate the Bose-Einstein condensation transition in a toroidally confined Bose gas using the stochastic projected Gross-Pitaevskii equation (SPGPE), with and without the energy-damping reservoir interaction. Energy-damping alters the scaling of the winding number distribution with the quench time - a departure from the universal KZM theory that relies on equilibrium critical exponents. Numerical values are obtained for the correlation-length critical exponent $\

  10. Reservoir interactions during Bose-Einstein condensation: modified critical scaling in the Kibble-Zurek mechanism of defect formation

    E-Print Network [OSTI]

    McDonald, R G

    2015-01-01

    As a test of the Kibble-Zurek mechanism (KZM) of defect formation, we simulate the Bose-Einstein condensation transition in a toroidally confined Bose gas using the stochastic projected Gross-Pitaevskii equation (SPGPE), with and without the energy-damping reservoir interaction. Energy-damping alters the scaling of the winding number distribution with the quench time - a departure from the universal KZM theory that relies on equilibrium critical exponents. Numerical values are obtained for the correlation-length critical exponent $\

  11. Determination of Electrochemical Performance and Thermo-Mechanical-Chemical Stability of SOFCs from Defect Modeling

    SciTech Connect (OSTI)

    Eric Wachsman; Keith L. Duncan

    2006-09-30

    This research was focused on two distinct but related issues. The first issue concerned using defect modeling to understand the relationship between point defect concentration and the electrochemical, thermo-chemical and mechano-chemical properties of typical solid oxide fuel cell (SOFC) materials. The second concerned developing relationships between the microstructural features of SOFC materials and their electrochemical performance. To understand the role point defects play in ceramics, a coherent analytical framework was used to develop expressions for the dependence of thermal expansion and elastic modulus on point defect concentration in ceramics. These models, collectively termed the continuum-level electrochemical model (CLEM), were validated through fits to experimental data from electrical conductivity, I-V characteristics, elastic modulus and thermo-chemical expansion experiments for (nominally pure) ceria, gadolinia-doped ceria (GDC) and yttria-stabilized zirconia (YSZ) with consistently good fits. The same values for the material constants were used in all of the fits, further validating our approach. As predicted by the continuum-level electrochemical model, the results reveal that the concentration of defects has a significant effect on the physical properties of ceramic materials and related devices. Specifically, for pure ceria and GDC, the elastic modulus decreased while the chemical expansion increased considerably in low partial pressures of oxygen. Conversely, the physical properties of YSZ remained insensitive to changes in oxygen partial pressure within the studied range. Again, the findings concurred exactly with the predictions of our analytical model. Indeed, further analysis of the results suggests that an increase in the point defect content weakens the attractive forces between atoms in fluorite-structured oxides. The reduction treatment effects on the flexural strength and the fracture toughness of pure ceria were also evaluated at room temperature. The results reveal that the flexural strength decreases significantly after heat treatment in very low oxygen partial pressure environments; however, in contrast, fracture toughness is increased by 30-40% when the oxygen partial pressure was decreased to 10{sup -20} to 10{sup -22} atm range. Fractographic studies show that microcracks developed at 800 oC upon hydrogen reduction are responsible for the decreased strength. To understand the role of microstructure on electrochemical performance, electrical impedance spectra from symmetric LSM/YSZ/LSM cells was de-convoluted to obtain the key electrochemical components of electrode performance, namely charge transfer resistance, surface diffusion of reactive species and bulk gas diffusion through the electrode pores. These properties were then related to microstructural features, such as triple-phase boundary length and tortuosity. From these experiments we found that the impedance due to oxygen adsorption obeys a power law with pore surface area, while the impedance due to charge transfer is found to obey a power-law with respect to triple phase boundary length. A model based on kinetic theory explaining the power-law relationships observed was then developed. Finally, during our EIS work on the symmetric LSM/YSZ/LSM cells a technique was developed to improve the quality of high-frequency impedance data and their subsequent de-convolution.

  12. On the mechanism of acceleration behavior of plasma bullet

    SciTech Connect (OSTI)

    Wu, S.; Lu, X., E-mail: luxinpei@hotmail.com; Pan, Y. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2014-07-15

    Two special experiments are designed to study the mechanism of the acceleration behavior of a plasma bullet when it exits a nozzle. First, a T-shape device is used to simulate the air diffusion when a plasma plume exits the nozzle. It is found that adding just 1% of N{sub 2}, O{sub 2}, or air to the main working gas He results in the acceleration of the plasma bullet. Second, materials of different permittivity are added to the left part of the outside of the tube. The experimental results show that the plasma bullet accelerates at the moment when it enters into the right part of the tube where there is no extra material on the outside of the tube. These two experiments confirm that the acceleration behavior of the plasma bullet when it exits the nozzle is due to the air diffusion, hence Penning ionization, and the permittivity change when the bullet exits the nozzle, for example, from a tube with high permittivity to air with low permittivity. Besides, electric field measurements show that the electric field in the bullet head increases when the plasma bullet accelerates. This confirms the electric field driven nature of the plasma bullet propagation.

  13. Fusion Engineering and Design 3940 (1998) 759764 Mechanical behavior and design database of packed beds for

    E-Print Network [OSTI]

    Abdou, Mohamed

    1998-01-01

    Fusion Engineering and Design 39­40 (1998) 759­764 Mechanical behavior and design database of packed beds for blanket designs Alice Y. Ying *, Zi Lu, Mohamed A. Abdou Mechanical and Aerospace to fusion solid breeder blanket designs need to be performed. In this paper, the mechanical behavior

  14. Atomistic simulation of defect structure evolution and mechanical properties at long time scales

    E-Print Network [OSTI]

    Fan, Yue, Ph. D. Massachusetts Institute of Technology

    2013-01-01

    This thesis is a computational and theoretical investigation of the response of materials' mechanical properties to a wide range of environmental conditions, with a particular focus on the coupled effects of strain rate ...

  15. Microstructure, Mechanical Behavior, and Clinical Trade-offs in Ultra-High Molecular Weight Polyethylene for Total Joint Replacement

    E-Print Network [OSTI]

    Atwood, Sara Anne

    2010-01-01

    2000). Degradation of mechanical behavior in UHMWPE afterCombined chemical and mechanical effects on free radicals inoxidation, and retain mechanical properties. Recipient of

  16. Microporosity is one of the major defects encountered in castings and is caused by two concomitant mechanisms: solidification shrinkage and gas segregation. It reduces mechanical properties of the cast part like fatigue life.

    E-Print Network [OSTI]

    Psaltis, Demetri

    mechanisms: solidification shrinkage and gas segregation. It reduces mechanical properties of the cast part·Microporosity is one of the major defects encountered in castings and is caused by two concomitant for multigas systems in multi-component alloys. Modeling of Casting, Welding and Adv. Solidif. Proc. XI, volume

  17. SISGR – Domain Microstructures and Mechanisms for Large, Reversible and Anhysteretic Strain Behaviors in Phase Transforming Ferroelectric Materials

    SciTech Connect (OSTI)

    Wang, Yu

    2013-12-06

    This four-year project (including one-year no-cost extension) aimed to advance fundamental understanding of field-induced strain behaviors of phase transforming ferroelectrics. We performed meso-scale phase field modeling and computer simulation to study domain evolutions, mechanisms and engineering techniques, and developed computational techniques for nanodomain diffraction analysis; to further support above originally planned tasks, we also carried out preliminary first-principles density functional theory calculations of point defects and domain walls to complement meso-scale computations as well as performed in-situ high-energy synchrotron X-ray single crystal diffraction experiments to guide theoretical development (both without extra cost to the project thanks to XSEDE supercomputers and DOE user facility Advanced Photon Source).

  18. Three-dimensional mechanical behavior of kaolin clay with controlled microfabric using true triaxial testing

    E-Print Network [OSTI]

    Prashant, Amit

    influence on the mechanical properties of soil, which makes the study of soil behavior to be a rather, (a) Flocculated, and (b) Dispersed Microfabric, (Penumadu, 1996) #12;problems in soil mechanics and formed the basis for several existing theories such as Critical State Soil Mechanics (Roscoe and Burland

  19. 2012 THIN FILM AND SMALL SCALE MECHANICAL BEHAVIOR GRS/GRC, JULY 21-27, 2012

    SciTech Connect (OSTI)

    Balk, Thomas

    2012-07-27

    The mechanical behavior of materials with small dimension(s) is of both fundamental scientific interest and technological relevance. The size effects and novel properties that arise from changes in deformation mechanism have important implications for modern technologies such as thin films for microelectronics and MEMS devices, thermal and tribological coatings, materials for energy production and advanced batteries, etc. The overarching goal of the 2012 Gordon Research Conference on "Thin Film and Small Scale Mechanical Behavior" is to discuss recent studies and future opportunities regarding elastic, plastic and time-dependent deformation, as well as degradation and failure mechanisms such as fatigue, fracture and wear. Specific topics of interest include, but are not limited to: fundamental studies of physical mechanisms governing small-scale mechanical behavior; advances in test techniques for materials at small length scales, such as nanotribology and high-temperature nanoindentation; in-situ mechanical testing and characterization; nanomechanics of battery materials, such as swelling-induced phenomena and chemomechanical behavior; flexible electronics; mechanical properties of graphene and carbon-based materials; mechanical behavior of small-scale biological structures and biomimetic materials. Both experimental and computational work will be included in the oral and poster presentations at this Conference.

  20. A Model for the Nonlinear Mechanical Behavior of Asphalt Binders and its Application in Prediction of Rutting Susceptibility 

    E-Print Network [OSTI]

    Srinivasa Parthasarathy, Atul

    2013-04-30

    The mechanical behavior of asphalt binders is nonlinear. The binders exhibit shear thinning/thickening behavior in steady shear tests and non-proportational behavior in other standard viscoelastic tests such as creep-recovery ...

  1. 3.91J / 1.593J Mechanical Behavior of Plastics, Spring 2003

    E-Print Network [OSTI]

    Roylance, David

    Relation among chemical composition, physical structure, and mechanical behavior of plastics or synthetic high polymers. Study of types of polymers; fundamentals of viscoelastic phenomena such as creep, stress relaxation, ...

  2. Mechanical behavior of closed-cell and hollow-sphere metallic foams

    E-Print Network [OSTI]

    Sanders, Wynn Steven, 1974-

    2002-01-01

    (cont.) The elastic anisotropy and yield surfaces are fully characterized, and numerical equations are developed to allow the simple evaluation of the effect of geometric and material properties on the mechanical behavior ...

  3. The influence of salinity on the mechanical behavior of high plasticity soils

    E-Print Network [OSTI]

    Fahy, Brian Patrick

    2014-01-01

    This thesis investigates the influence of salinity on the mechanical behavior of smectitic rich high plasticity soils resedimented with pore fluid salinities ranging from 0 to 256 g/L. An extensive laboratory testing program ...

  4. An Atomistic Study of the Mechanical Behavior of Carbon Nanotubes and Nanocomposite Interfaces 

    E-Print Network [OSTI]

    Awasthi, Amnaya P.

    2011-02-22

    The research presented in this dissertation pertains to the evaluation of stiffness of carbon nanotubes (CNTs) in a multiscale framework and modeling of the interfacial mechanical behavior in CNT-polymer nanocomposites. ...

  5. Factors Affecting the Mechanical Behavior of Bone Subrata Saha, Ph.D.

    E-Print Network [OSTI]

    Gilbert, Robert P.

    Factors Affecting the Mechanical Behavior of Bone by Subrata Saha, Ph.D. Research Professor-mail: subrata.saha@downstate.edu ABSTRACT The load carrying capacity of our skeletal system depends

  6. Behavioral mechanisms underlying the extinction of cocaine self-administration 

    E-Print Network [OSTI]

    Valles, Rodrigo, Jr.

    2006-04-12

    Neurotransmitters.................................................................................. 11 Dopamine.................................................................................. 11 Serotonin... nervous system (CNS), cocaine will target the transport reuptake mechanisms of 3 neurotransmitter systems: dopamine (DA), serotonin (5-HT) and norepinephrine (NE). This occurs in various loci throughout the brain. Of these, the most pertinent...

  7. The mechanical behavior of heavily overconsolidated resedimented Boston Blue Clay

    E-Print Network [OSTI]

    Vargas Bustamante, Albalyra Geraldine

    2013-01-01

    Geotechnical engineers encounter some of the most challenging problems in heavily overconsolidated soils. Clays under this condition originated in nature or man-made construction. This thesis investigates the mechanical ...

  8. Roles of nanofiller structure on mechanical behavior of thermoplastic nanocomposites 

    E-Print Network [OSTI]

    Weon, Jong Il

    2006-10-30

    -based models accurately describe the relationship between clay structural parameters and the corresponding moduli for exfoliated nanocomposites. The impact fracture mechanisms of polypropylene (PP)-calcium carbonate (CaCO3) nanoparticles have been investigated...

  9. Computational up-scaling of anisotropic swelling and mechanical behavior of hierarchical cellular material

    E-Print Network [OSTI]

    Rafsanjani, Ahmad; Wittel, Falk K; Carmeliet, Jan

    2015-01-01

    The hygro-mechanical behavior of a hierarchical cellular material, i.e. growth rings of softwood is investigated using a two-scale micro-mechanics model based on a computational homogenization technique. The lower scale considers the individual wood cells of varying geometry and dimensions. Honeycomb unit cells with periodic boundary conditions are utilized to calculate the mechanical properties and swelling coefficients of wood cells. Using the cellular scale results, the anisotropy in mechanical and swelling behavior of a growth ring in transverse directions is investigated. Predicted results are found to be comparable to experimental data. It is found that the orthotropic swelling properties of the cell wall in thin-walled earlywood cells produce anisotropic swelling behavior while, in thick latewood cells, this anisotropy vanishes. The proposed approach provides the ability to consider the complex microstructure when predicting the effective mechanical and swelling properties of softwood.

  10. Shedding Light on Nanocrystal Defects

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

    Shedding Light on Nanocrystal Defects Print Nanocrystals have been the focus of much scientific interest lately, given their various advantageous mechanical properties. Their...

  11. Processing and mechanical behavior of hypereutectoid steel wires

    SciTech Connect (OSTI)

    Lesuer, D.R.; Syn, C.K.; Sherby, O.D.; Kim, D.K.

    1996-06-25

    Hypereutectoid steels have the potential for dramatically increasing the strength of wire used in tire cord and in other high strength wire applications. The basis for this possible breakthrough is the elimination of a brittle proeutectoid network that can form along grain boundaries if appropriate processing procedures and alloy additions are used. A review is made of work done by Japanese and other researchers on eutectoid and mildly hypereutectoid wires. A linear extrapolation of the tensile strength of fine wires predicts higher strengths at higher carbon contents. The influence of processing, alloy additions and carbon content in optimizing the strength, ductility and fracture behavior of hypereutectoid steels is presented. It is proposed that the tensile strength of pearlitic wires is dictated by the fracture strength of the carbide lamella at grain boundary locations in the carbide. Methods to improve the strength of carbide grain boundaries and to decrease the carbide plate thickness will contribute to enhancing the ultrahigh strength obtainable in hypereutectoid steel wires. 23 refs., 13 figs., 1 tab.

  12. Crossover behavior in hydrogen sensing mechanism for palladium ultrathin films.

    SciTech Connect (OSTI)

    Darling, S. B.; Ramanathan, M.; Skudlarek, G.; Wang, H. H.; Illinois Math and Science Academy

    2010-01-01

    Palladium has been extensively studied as a material for hydrogen sensors because of the simplicity of its reversible resistance change when exposed to hydrogen gas. Various palladium films and nanostructures have been used, and different responses have been observed with these diverse morphologies. In some cases, such as with nanowires, the resistance will decrease, whereas in others, such as with thick films, the resistance will increase. Each of these mechanisms has been explored for several palladium structures, but the crossover between them has not been systematically investigated. Here we report on a study aimed at deciphering the nanostructure-property relationships of ultrathin palladium films used as hydrogen gas sensors. The crossover in these films is observed at a thickness of {approx} 5 nm. Ramifications for future sensor developments are discussed.

  13. The mechanical behavior of normally consolidated soils as a function of pore fluid salinity

    E-Print Network [OSTI]

    Horan, Aiden James

    2012-01-01

    Pore fluid salinities in the Gulf of Mexico area can reach levels of 250 grams of salt per liter of pore fluid (g/1). It is now necessary to determine the effect that this salinity level can play on the mechanical behaviors ...

  14. Mechanical behavior simulation of MEMS-based cantilever beam using COMSOL multiphysics

    SciTech Connect (OSTI)

    Acheli, A. Serhane, R.

    2015-03-30

    This paper presents the studies of mechanical behavior of MEMS cantilever beam made of poly-silicon material, using the coupling of three application modes (plane strain, electrostatics and the moving mesh) of COMSOL Multi-physics software. The cantilevers playing a key role in Micro Electro-Mechanical Systems (MEMS) devices (switches, resonators, etc) working under potential shock. This is why they require actuation under predetermined conditions, such as electrostatic force or inertial force. In this paper, we present mechanical behavior of a cantilever actuated by an electrostatic force. In addition to the simplification of calculations, the weight of the cantilever was not taken into account. Different parameters like beam displacement, electrostatics force and stress over the beam have been calculated by finite element method after having defining the geometry, the material of the cantilever model (fixed at one of ends but is free to move otherwise) and his operational space.

  15. Characterization of mechanical behavior of an epithelial monolayer in response to epidermal growth factor stimulation

    SciTech Connect (OSTI)

    Yang, Ruiguo; Chen, Jennifer Y.; Xi, Ning; Lai, King Wai Chiu; Qu, Chengeng; Fung, Carmen Kar Man; Penn, Lynn S.; Xi, Jun

    2012-03-10

    Cell signaling often causes changes in cellular mechanical properties. Knowledge of such changes can ultimately lead to insight into the complex network of cell signaling. In the current study, we employed a combination of atomic force microscopy (AFM) and quartz crystal microbalance with dissipation monitoring (QCM-D) to characterize the mechanical behavior of A431 cells in response to epidermal growth factor receptor (EGFR) signaling. From AFM, which probes the upper portion of an individual cell in a monolayer of cells, we observed increases in energy dissipation, Young's modulus, and hysteresivity. Increases in hysteresivity imply a shift toward a more fluid-like mechanical ordering state in the bodies of the cells. From QCM-D, which probes the basal area of the monolayer of cells collectively, we observed decreases in energy dissipation factor. This result suggests a shift toward a more solid-like state in the basal areas of the cells. The comparative analysis of these results indicates a regionally specific mechanical behavior of the cell in response to EGFR signaling and suggests a correlation between the time-dependent mechanical responses and the dynamic process of EGFR signaling. This study also demonstrates that a combination of AFM and QCM-D is able to provide a more complete and refined mechanical profile of the cells during cell signaling. -- Highlights: Black-Right-Pointing-Pointer The EGF-induced cellular mechanical response is regionally specific. Black-Right-Pointing-Pointer The EGF-induced cellular mechanical response is time and dose dependent. Black-Right-Pointing-Pointer A combination of AFM and QCM-D provides a more complete mechanical profile of cells.

  16. Simulation of localized barrier defects in resonant tunneling diodes 

    E-Print Network [OSTI]

    Stoneberg, Jason Neal

    1995-01-01

    defect assisted tunneling as a possible current mechanism. This study attempts to ascertain the effects of defect potentials in the barriers on current in a simulation of a double barrier resonant tunneling diode. Results indicate that these defects could...

  17. Tuning of the electro-mechanical behavior of the cellular carbon nanotube structures with nanoparticle dispersions

    SciTech Connect (OSTI)

    Gowda, Prarthana; Misra, Abha; Ramamurty, Upadrasta; Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah 21589

    2014-03-10

    The mechanical and electrical characteristics of cellular network of the carbon nanotubes (CNT) impregnated with metallic and nonmetallic nanoparticles were examined simultaneously by employing the nanoindentation technique. Experimental results show that the nanoparticle dispersion not only enhances the mechanical strength of the cellular CNT by two orders of magnitude but also imparts variable nonlinear electrical characteristics; the latter depends on the contact resistance between nanoparticles and CNT, which is shown to depend on the applied load while indentation. Impregnation with silver nanoparticles enhances the electrical conductance, the dispersion with copper oxide and zinc oxide nanoparticles reduces the conductance of CNT network. In all cases, a power law behavior with suppression in the differential conductivity at zero bias was noted, indicating electron tunneling through the channels formed at the CNT-nanoparticle interfaces. These results open avenues for designing cellular CNT foams with desired electro-mechanical properties and coupling.

  18. Percolation mechanism through trapping/de-trapping process at defect states for resistive switching devices with structure of Ag/Si{sub x}C{sub 1?x}/p-Si

    SciTech Connect (OSTI)

    Liu, Yanhong; Gao, Ping; Li, La; Peng, Wei [School of Physics and Optoelectronic Engineering, Dalian University of Technology, No. 2 Linggong Road, Ganjingzi District, Dalian 116024 (China); Jiang, Xuening; Zhang, Jialiang [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, No. 2 Linggong Road, Ganjingzi District, Dalian 116024 (China)

    2014-08-14

    Pure Si{sub x}C{sub 1?x} (x?>?0.5) and B-containing Si{sub x}C{sub 1?x} (x?>?0.5) based resistive switching devices (RSD) with the structure of Ag/Si{sub x}C{sub 1?x}/p-Si were fabricated and their switching characteristics and mechanism were investigated systematically. Percolation mechanism through trapping/ de-trapping at defect states was suggested for the switching process. Through the introduction of B atoms into Si{sub x}C{sub 1?x}, the density of defect states was reduced, then, the SET and RESET voltages were also decreased. Based on the percolation theory, the dependence of SET/RESET voltage on the density of defect states was analyzed. These results supply a deep understanding for the SiC-based RSD, which have a potential application in extreme ambient conditions.

  19. Effects of Stone-Wales and vacancy defects in atomic-scale friction on defective graphite

    SciTech Connect (OSTI)

    Sun, Xiao-Yu; Wu, RunNi; Xia, Re; Chu, Xi-Hua; Xu, Yuan-Jie

    2014-05-05

    Graphite is an excellent solid lubricant for surface coating, but its performance is significantly weakened by the vacancy or Stone-Wales (SW) defect. This study uses molecular dynamics simulations to explore the frictional behavior of a diamond tip sliding over a graphite which contains a single defect or stacked defects. Our results suggest that the friction on defective graphite shows a strong dependence on defect location and type. The 5-7-7-5 structure of SW defect results in an effectively negative slope of friction. For defective graphite containing a defect in the surface, adding a single vacancy in the interior layer will decrease the friction coefficients, while setting a SW defect in the interior layer may increase the friction coefficients. Our obtained results may provide useful information for understanding the atomic-scale friction properties of defective graphite.

  20. An experimental investigation into the stress-dependent mechanical behavior of cohesive soil with application to wellbore instability

    E-Print Network [OSTI]

    Abdulhadi, Naeem Omar

    2009-01-01

    This thesis investigates the mechanical behavior of cohesive soils with reference to the applications of wellbore instabilities through an extensive program of laboratory element and model borehole tests. The laboratory ...

  1. NUMERICAL SIMULATION FOR MECHANICAL BEHAVIOR OF U10MO MONOLITHIC MINIPLATES FOR RESEARCH AND TEST REACTORS

    SciTech Connect (OSTI)

    Hakan Ozaltun & Herman Shen

    2011-11-01

    This article presents assessment of the mechanical behavior of U-10wt% Mo (U10Mo) alloy based monolithic fuel plates subject to irradiation. Monolithic, plate-type fuel is a new fuel form being developed for research and test reactors to achieve higher uranium densities within the reactor core to allow the use of low-enriched uranium fuel in high-performance reactors. Identification of the stress/strain characteristics is important for understanding the in-reactor performance of these plate-type fuels. For this work, three distinct cases were considered: (1) fabrication induced residual stresses (2) thermal cycling of fabricated plates; and finally (3) transient mechanical behavior under actual operating conditions. Because the temperatures approach the melting temperature of the cladding during the fabrication and thermal cycling, high temperature material properties were incorporated to improve the accuracy. Once residual stress fields due to fabrication process were identified, solution was used as initial state for the subsequent simulations. For thermal cycling simulation, elasto-plastic material model with thermal creep was constructed and residual stresses caused by the fabrication process were included. For in-service simulation, coupled fluid-thermal-structural interaction was considered. First, temperature field on the plates was calculated and this field was used to compute the thermal stresses. For time dependent mechanical behavior, thermal creep of cladding, volumetric swelling and fission induced creep of the fuel foil were considered. The analysis showed that the stresses evolve very rapidly in the reactor. While swelling of the foil increases the stress of the foil, irradiation induced creep causes stress relaxation.

  2. Behavior of Turbulent Structures within a Mach 5 Mechanically Distorted Boundary Layer 

    E-Print Network [OSTI]

    Peltier, Scott Jacob

    2013-08-05

    stream_source_info PELTIER-DISSERTATION-2013.pdf.txt stream_content_type text/plain stream_size 560918 Content-Encoding ISO-8859-1 stream_name PELTIER-DISSERTATION-2013.pdf.txt Content-Type text/plain; charset=ISO-8859...-1 BEHAVIOR OF TURBULENT STRUCTURES WITHIN A MACH 5 MECHANICALLY DISTORTED BOUNDARY LAYER A Dissertation by SCOTT JACOB PELTIER Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements...

  3. Mechanisms Governing the Creep Behavior of High Temperature Alloys for Generation IV Nuclear Energy Systems

    SciTech Connect (OSTI)

    Vasudevan, Vijay; Carroll, Laura; Sham, Sam

    2015-04-06

    This research project, which includes collaborators from INL and ORNL, focuses on the study of alloy 617 and alloy 800H that are candidates for applications as intermediate heat exchangers in GEN IV nuclear reactors, with an emphasis on the effects of grain size, grain boundaries and second phases on the creep properties; the mechanisms of dislocation creep, diffusional creep and cavitation; the onset of tertiary creep; and theoretical modeling for long-term predictions of materials behavior and for high temperature alloy design.

  4. Damage mechanics characterization on fatigue behavior of a solder joint material

    SciTech Connect (OSTI)

    Chow, C.L.; Yang, F. [Univ. of Michigan, Dearborn, MI (United States). Dept. of Mechanical Engineering; Fang, H.E. [Sandia National Labs., Albuquerque, NM (United States). Computational Physics Dept.

    1998-08-01

    This paper presents the first part of a comprehensive mechanics approach capable of predicting the integrity and reliability of solder joint material under fatigue loading without viscoplastic damage considerations. A separate report will be made to present a comprehensive damage model describing life prediction of the solder material under thermomechanical fatigue loading. The method is based on a theory of damage mechanics which makes possible a macroscopic description of the successive material deterioration caused by the presence of microcracks/voids in engineering materials. A damage mechanics model based on the thermodynamic theory of irreversible processes with internal state variables is proposed and used to provide a unified approach in characterizing the cyclic behavior of a typical solder material. With the introduction of a damage effect tensor, the constitutive equations are derived to enable the formulation of a fatigue damage dissipative potential function and a fatigue damage criterion. The fatigue evolution is subsequently developed based on the hypothesis that the overall damage is induced by the accumulation of fatigue and plastic damage. This damage mechanics approach offers a systematic and versatile means that is effective in modeling the entire process of material failure ranging from damage initiation and propagation leading eventually to macro-crack initiation and growth. As the model takes into account the load history effect and the interaction between plasticity damage and fatigue damage, with the aid of a modified general purpose finite element program, the method can readily be applied to estimate the fatigue life of solder joints under different loading conditions.

  5. Mechanical noise dependent Aging and Shear Banding behavior of a mesoscopic model of amorphous plasticity

    E-Print Network [OSTI]

    Damien Vandembroucq; Stéphane Roux

    2011-12-05

    We discuss aging and localization in a simple "Eshelby" mesoscopic model of amorphous plasticity. Plastic deformation is assumed to occur through a series of local reorganizations. Using a discretization of the mechanical fields on a discrete lattice, local reorganizations are modeled as local slip events. Local yield stresses are randomly distributed in space and invariant in time. Each plastic slip event induces a long-ranged elastic stress redistribution. Mimicking the effect of aging, we focus on the behavior of the model when the initial state is characterized by a distribution of high local yield stress values. A dramatic effect on the localization behavior is obtained: the system first spontaneously self-traps to form a shear band which then only slowly widens. The higher the "age" parameter the more localized the plastic strain field. Two-time correlation computed on the stress field show a divergent correlation time with the age parameter. The amplitude of a local slip event (the prefactor of the Eshelby singularity) as compared to the yield stress distribution width acts here as an effective temperature-like parameter: the lower the slip increment, the higher the localization and the decorrelation time.

  6. The neuromolecular mechanisms that coordinate food availability with C. elegans male sexual behavior 

    E-Print Network [OSTI]

    Gruninger, Todd Ryan

    2009-05-15

    Organisms must coordinate behavioral and physiological responses to changingenvironmental conditions. In the nematode C. elegans, the presence or absence of foodin the environment affects many metabolic and behavioral ...

  7. Mass-Spring Model for Simulation of Heart Valve Tissue Mechanical Behavior Peter E. Hammer1,2,4,*

    E-Print Network [OSTI]

    1 Mass-Spring Model for Simulation of Heart Valve Tissue Mechanical Behavior Peter E. Hammer1, Cambridge, MA Abbreviated title: Mass-Spring Model for Simulation of Heart Valve Tissue * Address, MA, USA. E-mail address: peter.hammer@childrens.harvard.edu. #12;2 Abstract Heart valves

  8. Investigation of the Trapping Mechanism for Transient Current-Voltage Behavior In CIGSS-Based Solar Cells

    E-Print Network [OSTI]

    Sites, James R.

    exposure, and applied bias in cells fabricated by Siemens Solar Industries (SSI). When a constant biasInvestigation of the Trapping Mechanism for Transient Current-Voltage Behavior In CIGSS-Based Solar Cells Pamela K. Johnson1 , James R. Sites1 and Dale E. Tarrant2 1 Colorado State University, Fort

  9. 3D Simulation of Missing Pellet Surface Defects in Light Water Reactor Fuel Rods

    SciTech Connect (OSTI)

    B.W. Spencer; J.D. Hales; S.R. Novascone; R.L. Williamson

    2012-09-01

    The cladding on light water reactor (LWR) fuel rods provides a stable enclosure for fuel pellets and serves as a first barrier against fission product release. Consequently, it is important to design fuel to prevent cladding failure due to mechanical interactions with fuel pellets. Cladding stresses can be effectively limited by controlling power increase rates. However, it has been shown that local geometric irregularities caused by manufacturing defects known as missing pellet surfaces (MPS) in fuel pellets can lead to elevated cladding stresses that are sufficiently high to cause cladding failure. Accurate modeling of these defects can help prevent these types of failures. Nuclear fuel performance codes commonly use a 1.5D (axisymmetric, axially-stacked, one-dimensional radial) or 2D axisymmetric representation of the fuel rod. To study the effects of MPS defects, results from 1.5D or 2D fuel performance analyses are typically mapped to thermo-mechanical models that consist of a 2D plane-strain slice or a full 3D representation of the geometry of the pellet and clad in the region of the defect. The BISON fuel performance code developed at Idaho National Laboratory employs either a 2D axisymmetric or 3D representation of the full fuel rod. This allows for a computational model of the full fuel rod to include local defects. A 3D thermo-mechanical model is used to simulate the global fuel rod behavior, and includes effects on the thermal and mechanical behavior of the fuel due to accumulation of fission products, fission gas production and release, and the effects of fission gas accumulation on thermal conductivity across the fuel-clad gap. Local defects can be modeled simply by including them in the 3D fuel rod model, without the need for mapping between two separate models. This allows for the complete set of physics used in a fuel performance analysis to be included naturally in the computational representation of the local defect, and for the effects of the local defect to be coupled with the global fuel rod model. This approach for modeling fuel with MPS defects is demonstrated and compared with alternative techniques. The effects of varying parameters of the MPS defect are studied using this technique and presented here.

  10. Asperity-scale surface mechanics - Implications to adhesive contacts and microscale deformation behavior of rough surfaces

    E-Print Network [OSTI]

    Xu, Huaming

    2012-01-01

    K. , 2005a, “A Mechanics Approach to Static Friction of7 polishing A quasi-static mechanics analysis of three-Chapter 7 A quasi-static mechanics analysis of three-

  11. EFFECTS OF MORPHOLOGY ON THE MECHANICAL BEHAVIOR OF DUAL PHASE Fe/Si/C STEELS

    E-Print Network [OSTI]

    Kim, N.J.

    2012-01-01

    and ductility in dual phase steels. However, it seems thatmechanical behavior of dual phase steels. ACKNOWLEDGEMENTSL INTRODUCTION Dual phase steels whose structures consist of

  12. Numerical study of mechanical behavior of ceramic composites under compression loading in the framework of movable cellular automaton method

    SciTech Connect (OSTI)

    Konovalenko, Igor S. Smolin, Alexey Yu. Konovalenko, Ivan S.; Promakhov, Vladimir V.; Psakhie, Sergey G.

    2014-11-14

    Movable cellular automaton method was used for investigating the mechanical behavior of ceramic composites under uniaxial compression. A 2D numerical model of ceramic composites based on oxides of zirconium and aluminum with different structural parameters was developed using the SEM images of micro-sections of a real composite. The influence of such structural parameters as the geometrical dimensions of layers, inclusions, and their spatial distribution in the sample, the volume content of the composite components and their mechanical properties (as well as the amount of zirconium dioxide that underwent the phase transformation) on the fracture, strength, deformation and dissipative properties was investigated.

  13. Mechanical and optical behavior of a novel optical fiber crack sensor and an interferometric strain sensor

    E-Print Network [OSTI]

    Olson, Noah Gale, 1969-

    2002-01-01

    The proper interpretation of measurements from an optical fiber sensor requires a full understanding of its mechanical response to external action and the corresponding change in optical output. To quantify the mechanical ...

  14. Effects of irradiation on the mechanical behavior of twined SiC nanowires

    SciTech Connect (OSTI)

    Jin Enze; Niu Lisha; Lin Enqiang; Duan Zheng [AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China)

    2013-03-14

    Irradiation is known to bring new features in one-dimensional nano materials. In this study, we used molecular dynamics simulations to investigate the irradiation effects on twined SiC nanowires. Defects tend to accumulate from outside toward inside of the twined SiC nanowires with increasing irradiation dose, leading to a transition from brittle to ductile failure under tensile load. Atomic chains are formed in the ductile failure process. The first-principles calculations show that most of the atomic chains are metallic.

  15. Asperity-scale surface mechanics - Implications to adhesive contacts and microscale deformation behavior of rough surfaces

    E-Print Network [OSTI]

    Xu, Huaming

    2012-01-01

    Microtribology for Microelectromechanical Systems,” Wear,forces in microelectromechanical systems: mechanisms,Analysis Microelectromechanical Systems,” ASME J. Tribol. ,

  16. Asperity-scale surface mechanics - Implications to adhesive contacts and microscale deformation behavior of rough surfaces

    E-Print Network [OSTI]

    Xu, Huaming

    2012-01-01

    Microtribology for Microelectromechanical Systems,” Wear,forces in microelectromechanical systems: mechanisms,A Fractal Analysis Microelectromechanical Systems,” ASME J.

  17. Discrete particle transport in porous media : discrete observations of physical mechanisms influencing particle behavior

    E-Print Network [OSTI]

    Yoon, Joon Sik, 1973-

    2005-01-01

    An understanding of how discrete particles in the micron to submicron range behave in porous media is important to a number of environmental problems. Discrete particle behavior in the interior of a porous medium is complex ...

  18. The consolidation and strength behavior of mechanically compressed fine-grained sediments

    E-Print Network [OSTI]

    Casey, Brendan (Brendan Anthony)

    2014-01-01

    This thesis investigates the consolidation and shear strength behavior of saturated fine-grained sediments over the effective stress range of 0.1 to 100 MPa. The research makes use of samples which are resedimented in the ...

  19. Production, Characterization, and Mechanical Behavior of Cementitious Materials Incorporating Carbon Nanofibers 

    E-Print Network [OSTI]

    Yazdanbakhsh, Ardavan

    2012-10-19

    Carbon nanotubes (CNTs) and carbon nanofirbers (CNFs) have excellent properties (mechanical, electrical, magnetic, etc.), which can make them effective nanoreinforcements for improving the properties of materials. The ...

  20. Mechanical behavior of tissue simulants and soft tissues under extreme loading conditions

    E-Print Network [OSTI]

    Kalcioglu, Zeynep Ilke

    2013-01-01

    Recent developments in computer-integrated surgery and in tissue-engineered constructs necessitate advances in experimental and analytical techniques in characterizing properties of mechanically compliant materials such ...

  1. Dynamic behavior of Ni80Fe20 nanowires with controlled defects J. Ding, V. E. Demidov, M. G. Cottam, S. O. Demokritov, and A. O. Adeyeye

    E-Print Network [OSTI]

    Adeyeye, Adekunle

    and reversal mechanism of Fe filled Ni80Fe20 antidot nanostructures Appl. Phys. Lett. 100, 242411 (2012); 10 Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National for microwave devices1 and domain wall logic devices.2 Coupled nanowire arrays have also been investigated

  2. Point Defect Dynamics in Two-Dimensional Colloidal Crystals

    E-Print Network [OSTI]

    A. Libal; C. Reichhardt; C. J. Olson Reichhardt

    2006-12-16

    We study the topological configurations and dynamics of individual point defect vacancies and interstitials in a two-dimensional colloidal crystal. Our Brownian dynamics simulations show that the diffusion mechanism for vacancy defects occurs in two phases. The defect can glide along the crystal lattice directions, and it can rotate during an excited topological transition configuration to assume a different direction for the next period of gliding. The results for the vacancy defects are in good agreement with recent experiments. For the interstitial point defects, which were not studied in the experiments, we find several of the same modes of motion as in the vacancy defect case along with two additional diffusion pathways. The interstitial defects are more mobile than the vacancy defects due to the more two-dimensional nature of the diffusion of the interstitial defects.

  3. Configuration of ripple domains and their topological defects...

    Office of Scientific and Technical Information (OSTI)

    their topological defects formed under local mechanical stress on hexagonal monolayer graphene Citation Details In-Document Search Title: Configuration of ripple domains and their...

  4. Mechanical behaviors and phase transition of Ho{sub 2}O{sub 3} nanocrystals under high pressure

    SciTech Connect (OSTI)

    Yan, Xiaozhi [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Center for High Pressure Science and Technology Advanced Research (HPSTAR), 1690 Cailun Rd., Pudong, Shanghai 201203 (China); Ren, Xiangting [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); He, Duanwei, E-mail: duanweihe@scu.edu.cn, E-mail: yangwg@hpstar.ac.cn [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Institute of Fluid Physics and National Key Laboratory of Shockwave and Detonation Physic, China Academy of Engineering Physics, Mianyang 621900 (China); Chen, Bin [Center for High Pressure Science and Technology Advanced Research (HPSTAR), 1690 Cailun Rd., Pudong, Shanghai 201203 (China); Yang, Wenge, E-mail: duanweihe@scu.edu.cn, E-mail: yangwg@hpstar.ac.cn [Center for High Pressure Science and Technology Advanced Research (HPSTAR), 1690 Cailun Rd., Pudong, Shanghai 201203 (China); High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, 9700 S Cass Avenue, Argonne, Illinois 60439 (United States)

    2014-07-21

    Mechanical properties and phase transition often show quite large crystal size dependent behavior, especially at nanoscale under high pressure. Here, we have investigated Ho{sub 2}O{sub 3} nanocrystals with in-situ x-ray diffraction and Raman spectroscopy under high pressure up to 33.5?GPa. When compared to the structural transition routine cubic -> monoclinic -> hexagonal phase in bulk Ho{sub 2}O{sub 3} under high pressure, the nano-sized Ho{sub 2}O{sub 3} shows a much higher onset transition pressure from cubic to monoclinic structure and followed by a pressure-induced-amorphization under compression. The detailed analysis on the Q (Q?=?2?/d) dependent bulk moduli reveals the nanosized Ho{sub 2}O{sub 3} particles consist of a clear higher compressible shell and a less compressible core. Insight into these phenomena shed lights on micro-mechanism studies of the mechanical behavior and phase evolution for nanomaterials under high pressure, in general.

  5. Vehicle Technologies Office Merit Review 2014: Coupling of Mechanical Behavior of Cell Components to Electrochemical-Thermal Models for Computer-Aided Engineering of Batteries under Abuse

    Broader source: Energy.gov [DOE]

    Presentation given by NREL at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about coupling of mechanical behavior of cell...

  6. Analysis of thermal-hydrologic-mechanical behavior near an emplacementd rift at Yucca Mountain

    E-Print Network [OSTI]

    Rutqvist, Jonny; Tsang, Chin-Fu

    2002-01-01

    zone model of Y u c c a Mountain, Nevada. J. of Contam.at Y u c c a Mountain—the potential repository for high-Studies Facility Y u c c a Mountain, Nevada. Rock Mechanics

  7. The impact of mechanical properties of poly(ethylene glycol) hydrogels on vocal fold fibroblasts' behavior 

    E-Print Network [OSTI]

    Liao, Huimin

    2009-05-15

    hydrogel. This study demonstrates that different levels of VFF ECM formation may be achieved by varying the mechanical properties of PEG hydrogels and validates a systematic and controlled platform for further research of cell-biomaterials interaction....

  8. Role of the precentral cortex in adapting behavior to different mechanical environments

    E-Print Network [OSTI]

    Richardson, Andrew Garmory, 1977-

    2007-01-01

    We routinely produce movements under different mechanical contexts. All interactions with the physical environment, such as swinging a hammer or lifting a carton of milk, alter the forces experienced during movement. With ...

  9. Wave Mechanics: Behavior of a Distributed Electron Charge in an Atom

    E-Print Network [OSTI]

    Andrey Vasilyev

    2013-04-04

    In Part one of this Paper a hypothesis is forwarded of the electron charge in an atom existing in a distributed form. To check it by methods of electrodynamics and mechanics (without invoking the formalism of quantum mechanics and the concepts of the wave function and of the operators), the potential, kinetic, and total energies were calculated for three states of the hydrogen atom, which were found to agree closely with the available experimental data. The Part two of the Paper offers additional assumptions concerning various scenarios of motion of elements of the distributed electron charge which obey fully the laws of theoretical mechanics. The angular momentum of the ground-state hydrogen atom calculated in the frame of theoretical mechanics is shown to coincide with the spin which is $\\hbar/2$.

  10. Microstructure, mechanical property, biodegradation behavior, and biocompatibility of biodegradable FeFe2O3 composites

    E-Print Network [OSTI]

    Zheng, Yufeng

    applications. On the other hand, from the mechanical point of view, the properties of 316L stainless steel% by annealing. Both static and dynamic in vitro degradation test indicated a faster corrosion rate

  11. Size, effect of flexible proof mass on the mechanical behavior of micron-scale cantilevers for energy harvesting appications.

    SciTech Connect (OSTI)

    Kim, M.; Hong, S.; Miller, D. J.; Dugundji, J.; Wardle, B. L. (Materials Science Division); (MIT)

    2011-12-15

    Mechanical behavior of micron-scale cantilevers with a distributed, flexible proof mass is investigated to understand proof mass size effects on the performance of microelectromechanical system energy harvesters. Single-crystal silicon beams with proof masses of various lengths were fabricated using focused ion beam milling and tested using atomic force microscopy. Comparison of three different modeling results with measured data reveals that a 'two-beam' method has the most accurate predictive capability in terms of both resonant frequency and strain. Accurate strain prediction is essential because energy harvested scales with strain squared and maximum strain will be a design limit in fatigue.

  12. The Neural and Molecular Mechanisms Regulating Male Locomotion during Caenorhabditis elegans Mating Behavior 

    E-Print Network [OSTI]

    Sherlekar, Amrita Laxman

    2015-05-12

    ). The dopaminergic system along with the serotonergic system plays a role in impulsivity. More impulsive behavior leads to risky decisions where the individual is highly likely to make uninformed, random decisions rather than correct one (Cools et al., 2011... to reach the other side. Exposure of worms to endogenous serotonin or dopamine induces a deep ventral curling of male tail similar to the turning posture suggesting that these neurotransmitters are involved in inducing or modulating turning posture (Loer...

  13. Strain-induced kinetics of intergrain defects as the mechanism of slow dynamics in the nonlinear resonant response of humid sandstone bars

    E-Print Network [OSTI]

    resonant response of humid sandstone bars Oleksiy O. Vakhnenko,1 Vyacheslav O. Vakhnenko,2 Thomas J of sandstone bars, namely, (i) hysteretic behavior of a resonance curve on both its upward and downward slopes strain. In order to reproduce the highly nonlinear elastic features of sandstone grained structure

  14. James Earthman -Research Mechanical Behavior of Open Cellular Materials at Ambient and Elevated

    E-Print Network [OSTI]

    Mease, Kenneth D.

    in collaboration with Lawrence Livermore National Laboratory. Mechanisms of Corrosion Fatigue Damage in Implant and density into account. The present approach promises to provide improved predictions of corrosion fatigue Fasteners Riveted joint assemblies are common sites for the early onset of fatigue damage in aircraft

  15. ME 378K Mechanical Behavior of Materials ABET EC2000 syllabus

    E-Print Network [OSTI]

    Ben-Yakar, Adela

    of contemporary issues in engineering practice, including economic, social, political, and environmental issues. Apply principles of engineering, basic science, and mathematics (including multivariate calculus: For engineering majors, Mechanical Engineering 336 and 136L with a grade of at least C in each, and admission

  16. Microstructure and Mechanical Properties and Corrosion Behavior of Ti-Mo-Sn alloys

    E-Print Network [OSTI]

    Zheng, Yufeng

    , Y.B. Wang1,b 1 Center for Biomedical Materials and Engineering, Harbin Engineering University-discharge machining from the as-rolled sheets. After being cleaned with acetone, ethanol and distilled water in turn mechanically polished via a standard procedure to a wet sand paper of 2000# grit. Finally, all the specimens

  17. The effects of texture and composition on the mechanical behavior of experimentally deformed carbonate rocks 

    E-Print Network [OSTI]

    Hugman, Robert Harvey Harold

    1978-01-01

    behavior in unconfined tests and large increases in ultimate strength with increases in confining pressure to 100 MPa (Fig. 1, a, e). These "crystalline" rocks are moderately ductile to ductile at 100 MPa confining pressure. A degree of work hardening... Limestone (67 0 microcrystalline carbonate), and Madison H61-16 Lime- stone (54 $ micrite) are included in this category (Fig. 1, b, d, f), All these rocks are strong in unconfined tests, and stronger at 50 and 100 MPa confining pressure then Yule Marble...

  18. Extraordinary stiffness tunability through thermal expansion of nonlinear defect modes

    E-Print Network [OSTI]

    Marc Serra-Garcia; Joseph Lydon; Chiara Daraio

    2014-11-19

    Incremental stiffness characterizes the variation of a material's force response to a small deformation change. Typically materials have an incremental stiffness that is fixed and positive, but recent technologies, such as super-lenses, low frequency band gap materials and acoustic cloaks, are based on materials with zero, negative or extremely high incremental stiffness. So far, demonstrations of this behavior have been limited either to a narrow range of frequencies, temperatures, stiffness or to specific deformations. Here we demonstrate a mechanism to tune the static incremental stiffness that overcomes those limitations. This tunability is achieved by driving a nonlinear defect mode in a lattice. As in thermal expansion, the defect's vibration amplitude affects the force at the boundary, hence the lattice's stiffness. By using the high sensitivities of nonlinear systems near bifurcation points, we tune the magnitude of the incremental stiffness over a wide range: from positive, to zero, to arbitrarily negative values. The particular deformation where the incremental stiffness is modified can be arbitrarily selected varying the defect's driving frequency. We demonstrate this experimentally in a compressed array of spheres and propose a general theoretical model.

  19. Mechanical Behavior and Radiation Effects | U.S. DOE Office of Science (SC)

    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 wouldMass map shines light on dark matter By SarahMODELING CLOUD1 H(DiffractionMechanical

  20. Phase transformation and mechanical behavior in annealed 2205 duplex stainless steel welds

    SciTech Connect (OSTI)

    Badji, Riad Bouabdallah, Mabrouk; Bacroix, Brigitte; Kahloun, Charlie; Belkessa, Brahim; Maza, Halim

    2008-04-15

    The phase transformations and mechanical behaviour during welding and subsequent annealing treatment of 2205 duplex stainless steel have been investigated. Detailed microstructural examination showed the presence of higher ferrite amounts in the heat affected zone (HAZ), while higher amounts of austenite were recorded in the centre region of the weld metal. Annealing treatments in the temperature range of 800-1000 deg. C resulted in a precipitation of {sigma} phase and M{sub 23}C{sub 6} chromium carbides at the {gamma}/{delta} interfaces that were found to be preferential precipitation sites. Above 1050 deg. C, the volume fraction of {delta} ferrite increases with annealing temperature. The increase of {delta} ferrite occurs at a faster rate in the HAZ than in the base metal and fusion zone. Optimal mechanical properties and an acceptable ferrite/austenite ratio throughout the weld regions corresponds to annealing at 1050 deg. C. Fractographic examinations showed that the mode of failure changed from quasi-cleavage fracture to dimple rupture with an increase in the annealing temperature from 850 to 1050 deg. C.

  1. Modeling rough energy landscapes in defected condensed matter

    E-Print Network [OSTI]

    Monasterio Velásquez, Paul Rene

    2010-01-01

    This dissertation is a computational and theoretical investigation of the behavior of defected condensed matter and its evolution over long time scales. The thesis provides original contributions to the methodology used ...

  2. Intrinsic structural defects in monolayer molybdenum disulfide

    SciTech Connect (OSTI)

    Zhou, Wu [ORNL; Idrobo Tapia, Juan C [ORNL

    2013-01-01

    Monolayer molybdenum disulfide (MoS2) is a two-dimensional direct band gap semiconductor with distinctive mechanical, electronic, optical and chemical properties that can be utilized for novel nanoelectronics and optoelectronics devices. The performance of these electronic devices strongly depends on the quality and defect morphology of the MoS2 layers. Yet, little is known about the atomic structure of defects present in monolayer MoS2 and their influences on the material properties. Here we provide a systematic study of various intrinsic structural defects, including point defects, grain boundaries, and edges, in chemical vapor phase grown monolayer MoS2 via direct atomic resolution imaging, and explore their energy landscape and electronic properties using first-principles calculations. We discover that one-dimensional metallic wires can be created via two different types of 60 grain boundaries consisting of distinct 4-fold ring chains. A new type of edge reconstruction, representing a transition state during growth, was also identified, providing insights into the material growth mechanism. The atomic scale study of structural defects presented here brings new opportunities to tailor the properties of MoS2 via controlled synthesis and defect engineering.

  3. Final Technical Report of project: "Contactless Real-Time Monitoring of Paper Mechanical Behavior During Papermaking"

    SciTech Connect (OSTI)

    Emmanuel Lafond; Paul Ridgway; Ted Jackson; Rick Russo; Ken Telschow; Vance Deason; Yves Berthelot; David Griggs; Xinya Zhang; Gary Baum

    2005-08-30

    The early precursors of laser ultrasonics on paper were Prof. Y. Berthelot from the Georgia Institute of Technology/Mechanical Engineering department, and Prof. P. Brodeur from the Institute of Paper Science and Technology, both located in Atlanta, Georgia. The first Ph.D. thesis that shed quite some light on the topic, but also left some questions unanswered, was completed by Mont A. Johnson in 1996. Mont Johnson was Prof. Berthelot's student at Georgia Tech. In 1997 P. Brodeur proposed a project involving himself, Y. Berthelot, Dr. Ken Telschow and Mr. Vance Deason from INL, Honeywell-Measurex and Dr. Rick Russo from LBNL. The first time the proposal was not accepted and P. Brodeur decided to re-propose it without the involvement from LBNL. Rick Russo proposed a separate project on the same topic on his side. Both proposals were finally accepted and work started in the fall of 1997 on the two projects. Early on, the biggest challenge was to find an optical detection method which could detect laser-induced displacements of the web surface that are of the order of .1 micron in the ultrasonic range. This was to be done while the web was having an out-of-plane amplitude of motion in the mm range due to web flutter; while moving at 10 m/s to 30 m/s in the plane of the web, on the paper machine. Both teams grappled with the same problems and tried similar methods in some cases, but came up with two similar but different solutions one year later. The IPST, GT, INL team found that an interferometer made by Lasson Technologies Inc. using the photo-induced electro-motive force in Gallium Arsenide was able to detect ultrasonic waves up to 12-15 m/s. It also developed in house an interferometer using the Two-Wave Mixing effect in photorefractive crystals that showed good promises for on-line applications, and experimented with a scanning mirror to reduce motion-induced texture noise from the web and improve signal to noise ratio. On its side, LBNL had the idea to combine a commercial Mach-Zehnder interferometer to a spinning mirror synchronized to the web speed, in order to make almost stationary measurements. The method was demonstrated at up to 10 m/s. Both teams developed their own version of a web simulator that was driving a web of paper at 10 m/s or higher. The Department of Energy and members of the Agenda 2020 started to make a push for merging the two projects. This made sense because their topics were really identical but this was not well received by Prof. Brodeur. Finally IPST decided to reassign the direction of the IPST-INL-GT project in the spring of 1999 to Prof. Chuck Habeger so that the two teams could work together. Also at this time, Honeywell-Measurex dropped as a member of the team. It was replaced by ABB Industrial Systems whose engineers had extensive previous experience of working with ultrasonic sensors on paperboard. INL also finished its work on the project as its competencies were partly redundant with LBNL. From the summer of 1999, the IPST-GT and LBNL teams were working together and helped each other often by collaborating and visiting either laboratory when was necessary. Around the beginning of 2000, began an effort at IPST to create an off-line laser-ultrasonics instrument that could perform automated measurements of paper and paperboard's bending stiffness. It was widely known that the mechanical bending tests of paper used for years by the paper industry were very inaccurate and exhibited poor reproducibility; therefore the team needed a new instrument of reference to validate its future on-line results. In 1999-2000, the focus of the on-line instrument was on a pre-industrial demonstration on a pilot coater while reducing the damage to the web caused by the generation laser, below the threshold where it could be visible by the naked eye. During the spring of 2000 Paul Ridgway traveled to IPST and brought with him a redesigned system still using the same Mach-Zehnder interferometer as before, but this time employing an electric motor-driven spinning mirror instead of the previously belt-driven m

  4. Some Remarks on an Experiment Suggesting Quantum Like Behavior of Cognitive Entities and Formulation of an Abstract Quantum Mechanical Formalism to Describe Cognitive Entity and its Dynamics

    E-Print Network [OSTI]

    Elio Conte; Orlando Todarello; Antonio Federici; Francesco Vitiello; Michele Lopane; Andrei Khrennikov; Joseph P. Zbilut

    2007-10-26

    We have executed for the first time an experiment on mental observables concluding that there exists equivalence (that is to say, quantum like behavior) between quantum and cognitive entities.Such result has enabled us to formulate an abstract quantum mechanical formalism that is able to describe cognitive entities and their time dynamics.

  5. Enhancing metal-insulator-insulator-metal tunnel diodes via defect enhanced direct tunneling

    SciTech Connect (OSTI)

    Alimardani, Nasir; Conley, John F.

    2014-08-25

    Metal-insulator-insulator-metal tunnel diodes with dissimilar work function electrodes and nanolaminate Al{sub 2}O{sub 3}-Ta{sub 2}O{sub 5} bilayer tunnel barriers deposited by atomic layer deposition are investigated. This combination of high and low electron affinity insulators, each with different dominant conduction mechanisms (tunneling and Frenkel-Poole emission), results in improved low voltage asymmetry and non-linearity of current versus voltage behavior. These improvements are due to defect enhanced direct tunneling in which electrons transport across the Ta{sub 2}O{sub 5} via defect based conduction before tunneling directly through the Al{sub 2}O{sub 3}, effectively narrowing the tunnel barrier. Conduction through the device is dominated by tunneling, and operation is relatively insensitive to temperature.

  6. Defect-free ZnO nanorods for low temperature hydrogen sensor applications

    SciTech Connect (OSTI)

    Ranwa, Sapana; Kumar, Mahesh; Kulriya, Pawan K.; Sahu, Vikas Kumar; Kukreja, L. M.

    2014-11-24

    Uniformly distributed and defect-free vertically aligned ZnO nanorods (NRs) with high aspect ratio are deposited on Si by sputtering technique. X-ray diffraction along with transmission electron microscopy studies confirmed the single crystalline wurtzite structure of ZnO. Absence of wide band emission in photoluminescence spectra showed defect-free growth of ZnO NRs which was further conformed by diamagnetic behavior of the NRs. H{sub 2} sensing mechanism based on the change in physical dimension of channel is proposed to explain the fast response (?21.6?s) and recovery times (?27?s) of ZnO NRs/Si/ZnO NRs sensors. Proposed H{sub 2} sensor operates at low temperature (?70?°C) unlike the existing high temperature (>150?°C) sensors.

  7. Measuring Point Defect Density in Individual Carbon Nanotubes Using

    E-Print Network [OSTI]

    Hitchcock, Adam P.

    Defects are known to reduce mechanical strength and Young modulus of the CNT and disrupt their electrical, and bending of the basal planes. Prolonged ex- posure shrinks MWCNTs and eventually re- moves their central not quantitative or show limited spatial resolution. In this paper, we demonstrate a new method to visualize defect

  8. Structural phase transitions and topological defects in ion Coulomb crystals

    SciTech Connect (OSTI)

    Partner, Heather L.; Nigmatullin, Ramil; Burgermeister, Tobias; Keller, Jonas; Pyka, Karsten; Plenio, Martin B.; Retzker, Alex; Zurek, Wojciech Hubert; del Campo, Adolfo; Mehlstaubler, Tanja E.

    2014-11-19

    We use laser-cooled ion Coulomb crystals in the well-controlled environment of a harmonic radiofrequency ion trap to investigate phase transitions and defect formation. Topological defects in ion Coulomb crystals (kinks) have been recently proposed for studies of nonlinear physics with solitons and as carriers of quantum information. Defects form when a symmetry breaking phase transition is crossed non-adiabatically. For a second order phase transition, the Kibble-Zurek mechanism predicts that the formation of these defects follows a power law scaling in the rate of the transition. We demonstrate a scaling of defect density and describe kink dynamics and stability. We further discuss the implementation of mass defects and electric fields as first steps toward controlled kink preparation and manipulation.

  9. Polymer and polymer matrix composite (PMC) materials are being used extensively in different civil and mechanical engineering applications. The behavior of the epoxy resin polymers under different types of loading conditions has

    E-Print Network [OSTI]

    Polymer and polymer matrix composite (PMC) materials are being used extensively in different civil and mechanical engineering applications. The behavior of the epoxy resin polymers under different types of loading conditions has to be understood before the mechanical behavior of Polymer Matrix Composites (PMCs

  10. Elastic interactions between 2D geometric defects

    E-Print Network [OSTI]

    Michael Moshe; Eran Sharon; Raz Kupferman

    2015-10-13

    In this paper, we introduce a methodology applicable to a wide range of localized two-dimensional sources of stress. This methodology is based on a geometric formulation of elasticity. Localized sources of stress are viewed as singular defects---point charges of the curvature associated with a reference metric. The stress field in the presence of defects can be solved using a scalar stress function that generalizes the classical Airy stress function to the case of materials with nontrivial geometry. This approach allows the calculation of interaction energies between various types of defects. We apply our methodology to two physical systems: shear-induced failure of amorphous materials and the mechanical interaction between contracting cells.

  11. Affine Defects and Gravitation

    E-Print Network [OSTI]

    R. J. Petti

    2014-12-12

    We argue that the structure general relativity (GR) as a theory of affine defects is deeper than the standard interpretation as a metric theory of gravitation. Einstein-Cartan theory (EC), with its inhomogenous affine symmetry, should be the standard-bearer for GR-like theories. A discrete affine interpretation of EC (and gauge theory) yields topological definitions of momentum and spin (and Yang Mills current), and their conservation laws become discrete topological identities. Considerations from quantum theory provide evidence that discrete affine defects are the physical foundation for gravitation.

  12. Motivation Defect correction The algorithm Summary Defect correction in optimization

    E-Print Network [OSTI]

    Hemker, P.W.

    Motivation Defect correction The algorithm Summary Defect correction in optimization "Manifold Mapping" P.W. Hemker IPIR/CWI/UvA June 11, 2010 Manifold Mapping P.W. Hemker #12;Motivation Defect correction The algorithm Summary Motivation Motivation determine x1, x2, x1, x3, x4, x5, x6, x7 Manifold

  13. Modelling of thermo-mechanical and irradiation behavior of metallic and oxide fuels for sodium fast reactors

    E-Print Network [OSTI]

    Karahan, Aydin

    2009-01-01

    A robust and reliable code to model the irradiation behavior of metal and oxide fuels in sodium cooled fast reactors is developed. Modeling capability was enhanced by adopting a non-empirical mechanistic approach to the ...

  14. Defect mapping system

    DOE Patents [OSTI]

    Sopori, B.L.

    1995-04-11

    Apparatus for detecting and mapping defects in the surfaces of polycrystalline materials in a manner that distinguishes dislocation pits from grain boundaries includes a laser for illuminating a wide spot on the surface of the material, a light integrating sphere with apertures for capturing light scattered by etched dislocation pits in an intermediate range away from specular reflection while allowing light scattered by etched grain boundaries in a near range from specular reflection to pass through, and optical detection devices for detecting and measuring intensities of the respective intermediate scattered light and near specular scattered light. A center blocking aperture or filter can be used to screen out specular reflected light, which would be reflected by nondefect portions of the polycrystalline material surface. An X-Y translation stage for mounting the polycrystalline material and signal processing and computer equipment accommodate rastor mapping, recording, and displaying of respective dislocation and grain boundary defect densities. A special etch procedure is included, which prepares the polycrystalline material surface to produce distinguishable intermediate and near specular light scattering in patterns that have statistical relevance to the dislocation and grain boundary defect densities. 20 figures.

  15. Long-Term Mechanical Behavior of Yucca Mountain Tuff and its Variability, Final Technical Report for Task ORD-FY04-021

    SciTech Connect (OSTI)

    Daemen, Jaak J.K.; Ma, Lumin; Zhao, Guohua

    2006-03-20

    The study of the long term mechanical behavior of Yucca Mountain tuffs is important for several reasons. Long term stability of excavations will affect accessibility (e.g. for inspection purposes), and retrievability. Long term instabilities may induce loading of drip shields and/or emplaced waste, thus affecting drip shield and/or waste package corrosion. Failure of excavations will affect airflow, may affect water flow, and may affect temperature distributions. The long term mechanical behavior of rocks remains an elusive topic, loaded with uncertainties. A variety of approaches have been used to improve the understanding of this complex subject, but it is doubtful that it has reached a stage where firm predictions can be considered feasible. The long term mechanical behavior of "soft" rocks, especially evaporites, and in particular rock salt, has been the subject of numerous investigations (e.g. Cristescu and Hunsche, 1998, Cristescu et al, 2002), and basic approaches towards engineering taking into account the long term behavior of such materials have long been well established (e.g. Dreyer, 1972, 1982). The same is certainly not true of "hard" rocks. While it long has been recognized that the long term strength of ?hard? rocks almost certainly is significantly less than that measured during "short", i.e. standard (ASTM D 2938), ISRM suggested (Bieniawski et al, 1978) and conventionally used test procedures (e.g. Bieniawski, 1970, Wawersik, 1972, Hoek and Brown, 1980, p. 150), what limited approaches have been taken to develop strategies toward determining the long term mechanical behavior of "hard" rock remain in the early research and investigation stage, at best. One early model developed specifically for time dependent analysis of underground "hard" rock structures is the phenomenological model by Kaiser and Morgenstern (1981). Brady and Brown (1985, p. 93) state that over a wide range of strain rates, from 10^-8 to 10^2/s the difference in strength is only a factor of 2, and that "the observed behavior of rock is not significantly influenced by varying the strain rate within the range that is convenient to use in quasi-static laboratory compression tests." While this is undoubtedly true, it does not really address the question as to whether or not strengths thus measured can be considered appropriate for estimating long term strengths. One objective of this investigation was to evaluate the applicability of the approaches by Cruden (e.g. Cruden, 1971, 1974, 1983, 1987) and by Lajtai (e.g. Lajtai and Schmidtke, 1986, 1987) to the prediction of the long term mechanical behavior of the investigated tuffs. This involves in particular static fatigue testing, by conducting uniaxial, triaxial, and indirect splitting (Brazilian) tests over a wide range of strain (or stress, or displacement) rates.

  16. Mechanical relaxation behavior of polyurethanes reinforced with the in situ-generated sodium silica-polyphosphate nanophase

    E-Print Network [OSTI]

    V. O. Dupanov; S. M. Ponomarenko

    2014-10-31

    Further exploration of hybrid organic/inorganic composites (polyurethane based with inorganic material sodium silica polyphosphate) properties with mechanical relaxometer gives ability to analyze microstructure of such materials in terms of chain reptation tubes filler's fractal aggregates and stress amplification.

  17. Microstructural Characterization of the Chemo-mechanical Behavior of Asphalt in Terms of Aging and Fatigue Performance Properties 

    E-Print Network [OSTI]

    Allen, Robert Grover

    2013-03-27

    The study of asphalt chemo-mechanics requires a basic understanding of the physical properties and chemical composition of asphalt and how these properties are linked to changes in performance induced by chemical modifications. ...

  18. Nematic cells with defect-patterned alignment layers

    E-Print Network [OSTI]

    Adam S. Backer; A. C. Callan-Jones; Robert A. Pelcovits

    2007-08-29

    Using Monte Carlo simulations of the Lebwohl--Lasher model we study the director ordering in a nematic cell where the top and bottom surfaces are patterned with a lattice of $\\pm 1$ point topological defects of lattice spacing $a$. We find that the nematic order depends crucially on the ratio of the height of the cell $H$ to $a$. When $H/a \\gtrsim 0.9$ the system is very well--ordered and the frustration induced by the lattice of defects is relieved by a network of half--integer defect lines which emerge from the point defects and hug the top and bottom surfaces of the cell. When $H/a \\lesssim 0.9$ the system is disordered and the half--integer defect lines thread through the cell joining point defects on the top and bottom surfaces. We present a simple physical argument in terms of the length of the defect lines to explain these results. To facilitate eventual comparison with experimental systems we also simulate optical textures and study the switching behavior in the presence of an electric field.

  19. Mechanical behavior of AISI 304SS determined by miniature test methods after neutron irradiation to 28 dpa

    SciTech Connect (OSTI)

    Ellen M. Rabenberg; Brian J. Jaques; Bulent H. Sencer; Frank A. Garner; Paula D. Freyer; Taira Okita; Darryl P. Butt

    2014-05-01

    The mechanical properties of AISI 304 stainless steel irradiated for over a decade in the Experimental Breeder Reactor (EBR-II) were measured using miniature mechanical testing methods. The shear punch method was used to evaluate the shear strengths of the neutron-irradiated steel and a correlation factor was empirically determined to predict its tensile strength. The strength of the stainless steel slightly decreased with increasing irradiation temperature, and significantly increased with increasing dose until it saturated above approximately 5 dpa. Ferromagnetic measurements were used to observe and deduce the effects of the stress-induced austenite to martensite transformation as a result of shear punch testing.

  20. Application of the multi-mechanism deformation model for three-dimensional simulations of salt : behavior for the strategic petroleum reserve.

    SciTech Connect (OSTI)

    Ehgartner, Brian L.; Sobolik, Steven Ronald; Bean, James E.

    2010-07-01

    The U.S. Strategic Petroleum Reserve stores crude oil in 62 solution-mined caverns in salt domes located in Texas and Louisiana. Historically, three-dimensional geomechanical simulations of the behavior of the caverns have been performed using a power law creep model. Using this method, and calibrating the creep coefficient to field data such as cavern closure and surface subsidence, has produced varying degrees of agreement with observed phenomena. However, as new salt dome locations are considered for oil storage facilities, pre-construction geomechanical analyses are required that need site-specific parameters developed from laboratory data obtained from core samples. The multi-mechanism deformation (M-D) model is a rigorous mathematical description of both transient and steady-state creep phenomena. Recent enhancements to the numerical integration algorithm within the model have created a more numerically stable implementation of the M-D model. This report presents computational analyses to compare the results of predictions of the geomechanical behavior at the West Hackberry SPR site using both models. The recently-published results using the power law creep model produced excellent agreement with an extensive set of field data. The M-D model results show similar agreement using parameters developed directly from laboratory data. It is also used to predict the behavior for the construction and operation of oil storage caverns at a new site, to identify potential problems before a final cavern layout is designed.

  1. UNIVERSALITY OF PHASE TRANSITION DYNAMICS: TOPOLOGICAL DEFECTS FROM SYMMETRY BREAKING

    SciTech Connect (OSTI)

    Zurek, Wojciech H.; Del Campo, Adolfo

    2014-02-13

    In the course of a non-equilibrium continuous phase transition, the dynamics ceases to be adiabatic in the vicinity of the critical point as a result of the critical slowing down (the divergence of the relaxation time in the neighborhood of the critical point). This enforces a local choice of the broken symmetry and can lead to the formation of topological defects. The Kibble-Zurek mechanism (KZM) was developed to describe the associated nonequilibrium dynamics and to estimate the density of defects as a function of the quench rate through the transition. During recent years, several new experiments investigating formation of defects in phase transitions induced by a quench both in classical and quantum mechanical systems were carried out. At the same time, some established results were called into question. We review and analyze the Kibble-Zurek mechanism focusing in particular on this surge of activity, and suggest possible directions for further progress.

  2. Review on the effects of hydrogen at extreme pressures and temperatures on the mechanical behavior of polymers.

    SciTech Connect (OSTI)

    Hecht, Ethan S.

    2013-03-01

    The effects of hydrogen on the mechanics (e.g. strength, ductility, and fatigue resistance) of polymer materials are outlined in this report. There are a small number of studies reported in the literature on this topic, and even fewer at the extreme temperatures to which hydrogen service materials will be exposed. Several studies found little evidence that hydrogen affects the static tensile properties, long term creep, or ductile fracture of high density polyethylene or polyamide. However, there has been a report that a recoverable drop in the modulus of high density polyethylene is observable under high hydrogen pressure. A research need exists on the mechanical effects of hydrogen on the wide range of polymers used or considered for use in the hydrogen economy, due to the lack of data in the literature.

  3. Radiation induced effects on mechanical properties of nanoporous gold foams

    SciTech Connect (OSTI)

    Caro, M., E-mail: magda@lanl.gov, E-mail: efu@pku.edu.cn; Fu, E. G., E-mail: magda@lanl.gov, E-mail: efu@pku.edu.cn; Wang, Y. Q.; Martinez, E.; Caro, A. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Mook, W. M.; Sheehan, C.; Baldwin, J. K. [Center for Integrated Nanotechnology, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-06-09

    It has recently been shown that due to a high surface-to-volume ratio, nanoporous materials display radiation tolerance. The abundance of surfaces, which are perfect sinks for defects, and the relation between ligament size, defect diffusion, and time combine to define a window of radiation resistance [Fu et al., Appl. Phys. Lett. 101, 191607 (2012)]. Outside this window, the dominant defect created by irradiation in Au nanofoams are stacking fault tetrahedra (SFT). Molecular dynamics computer simulations of nanopillars, taken as the elemental constituent of foams, predict that SFTs act as dislocation sources inducing softening, in contrast to the usual behavior in bulk materials, where defects are obstacles to dislocation motion, producing hardening. In this work we test that prediction and answer the question whether irradiation actually hardens or softens a nanofam. Ne ion irradiations of gold nanofoams were performed at room temperature for a total dose up to 4 dpa, and their mechanical behavior was measured by nanoindentation. We find that hardness increases after irradiation, a result that we analyze in terms of the role of SFTs on the deformation mode of foams.

  4. Effect of cerium on structure modifications of a hybrid sol–gel coating, its mechanical properties and anti-corrosion behavior

    SciTech Connect (OSTI)

    Cambon, Jean-Baptiste, E-mail: cambon@chimie.ups-tlse.fr [Institut Carnot CIRIMAT, Université de Toulouse, UMR CNRS 5085, 118 Route de Narbonne, 31062 Toulouse Cedex 9 (France)] [Institut Carnot CIRIMAT, Université de Toulouse, UMR CNRS 5085, 118 Route de Narbonne, 31062 Toulouse Cedex 9 (France); Esteban, Julien; Ansart, Florence; Bonino, Jean-Pierre; Turq, Viviane [Institut Carnot CIRIMAT, Université de Toulouse, UMR CNRS 5085, 118 Route de Narbonne, 31062 Toulouse Cedex 9 (France)] [Institut Carnot CIRIMAT, Université de Toulouse, UMR CNRS 5085, 118 Route de Narbonne, 31062 Toulouse Cedex 9 (France); Santagneli, S.H.; Santilli, C.V.; Pulcinelli, S.H. [Departamento F?sico-Química, Instituto de Química, Universidade Estadual Paulista, UNESP, CP 355, 14801-970 Araraquara, SP (Brazil)] [Departamento F?sico-Química, Instituto de Química, Universidade Estadual Paulista, UNESP, CP 355, 14801-970 Araraquara, SP (Brazil)

    2012-11-15

    Highlights: ? New sol–gel routes to replace chromates for corrosion protection of aluminum. ? Effect of cerium concentration on the microstructure of xerogel. ? Electrochemical and mechanical performances of hybrid coating with different cerium contents. ? Good correlation between the different results with an optimal cerium content of 0.01 M. -- Abstract: An organic–inorganic hybrid coating was developed to improve the corrosion resistance of the aluminum alloy AA 2024-T3. Organic and inorganic coatings derived from glycidoxypropyl-trimethoxysilane (GPTMS) and aluminum tri-sec-butoxide Al(O{sup s}Bu){sub 3}, with different cerium contents, were deposited onto aluminum by dip-coating process. Corrosion resistance and mechanical properties were investigated by electrochemical impedance measurements and nano-indentation respectively. An optimal cerium concentration of 0.01 M was evidenced. To correlate and explain the hybrid coating performances in relation to the cerium content, NMR experiments were performed. It has been shown that when the cerium concentration in the hybrid is higher than 0.01 M there are important modifications in the hybrid structure that account for the mechanical properties and anti-corrosion behavior of the sol–gel coating.

  5. Holographic Chern-Simons Defects

    E-Print Network [OSTI]

    Fujita, Mitsutoshi; Meyer, Rene; Sugimoto, Shigeki

    2016-01-01

    We study SU(N) Yang-Mills-Chern-Simons theory in the presence of defects that shift the Chern-Simons level from a holographic point of view by embedding the system in string theory. The model is a D3-D7 system in Type IIB string theory, whose gravity dual is given by the AdS soliton background with probe D7-branes attaching to the AdS boundary along the defects. We holographically renormalize the free energy of the defect system with sources, from which we obtain the correlation functions for certain operators naturally associated to these defects. We find interesting phase transitions when the separation of the defects as well as the temperature are varied. We also discuss some implications for the Fractional Quantum Hall Effect and for two-dimensional QCD.

  6. Behavior of passaged chondrocytes in collagen-glycosaminoglycan scaffolds : effects of cross-linking, mechanical loading, and genetic modification of the scaffold

    E-Print Network [OSTI]

    Lee, Cynthia R. (Cynthia Renee), 1975-

    2002-01-01

    Tissue engineering is a promising solution to the problematic healing of cartilage defects. The purpose of this thesis was to establish a foundation for the development of a collagen-glycosaminoglycan (CG) scaffold for ...

  7. Effect of reinforcing particle type on morphology and age-hardening behavior of Al–4.5 wt.% Cu based nanocomposites synthesized through mechanical milling

    SciTech Connect (OSTI)

    Mostaed, A.; Saghafian, H.; Mostaed, E.; Shokuhfar, A.; Rezaie, H.R.

    2013-02-15

    The effects of reinforcing particle type (SiC and TiC) on morphology and precipitation hardening behavior of Al–4.5%Cu based nanocomposites synthesized via mechanical milling were investigated in the current work. In order to study the microstructure and morphology of mechanically milled powder, X-ray diffraction technique, scanning electron microscopy and high resolution transmission electron microscopy were utilized. Results revealed that at the early stages of mechanical milling, when reinforcing particles are polycrystal, the alloying process is enhanced more in the case of using the TiC particles as reinforcement. But, at the final stages of mechanical milling, when reinforcing particles are single crystal, the alloying process is enhanced more in the case of using the SiC ones. Transmission electron microscopy results demonstrated that Al–4.5 wt.%Cu based nanocomposite powders were synthesized and confirmed that the mutual diffusion of aluminum and copper occurs through the interfacial plane of (200). The hardness results showed that not only does introducing 4 vol.% of reinforcing particles (SiC or TiC) considerably decrease the porosity of the bulk composite samples, but also it approximately doubles the hardness of Al–4.5 wt.%Cu alloy (53.4 HB). Finally, apart from TEM and scanning electron microscopy observation which are localized, a decline in hardness in the TiC and SiC contained samples, respectively, after 1.5 and 2 h aging time at 473 K proves the fact that the size of SiC particles is smaller than the size of the TiC ones. - Highlights: ? HRTEM results show mutual diffusion of Al and Cu occurs through the (200) planes. ? TiC particles enhance alloying process more than the SiC ones at the early stages of MM. ? SiC particles enhance alloying process more than the TiC ones at the final stages of MM.

  8. The effect of magnetic field on bistability in 1D photonic crystal doped by magnetized plasma and coupled nonlinear defects

    SciTech Connect (OSTI)

    Mehdian, H.; Mohammadzahery, Z.; Hasanbeigi, A. [Department of Physics and Institute for Plasma Research, Kharazmi University, 49 Dr Mofatteh Avenue, Tehran 15614 (Iran, Islamic Republic of)] [Department of Physics and Institute for Plasma Research, Kharazmi University, 49 Dr Mofatteh Avenue, Tehran 15614 (Iran, Islamic Republic of)

    2014-01-15

    In this work, we study the defect mode and bistability behavior of 1-D photonic band gap structure with magnetized plasma and coupled nonlinear defects. The transfer matrix method has been employed to investigate the magnetic field effect on defect mode frequency and bistability threshold. The obtained results show that the frequency of defect mode and bistability threshold can be altered, without changing the structure of the photonic multilayer. Therefore, the bistability behavior of the subjected structure in the presence of magnetized plasma can be utilized in manufacturing wide frequency range devices.

  9. Dependence of the mechanical behavior of alloys on their electron work function—An alternative parameter for materials design

    SciTech Connect (OSTI)

    Lu, Hao; Hua, Guomin; Li, Dongyang, E-mail: dongyang.li@ualberta.ca [Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 2V4 (Canada)] [Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 2V4 (Canada)

    2013-12-23

    In this article, we demonstrate that the electron work function (EWF) as an intrinsic parameter can provide information or clues in a simple or straightforward way for material design, modification, and development. A higher work function of a material represents a more stable electronic state, which consequently generates a higher resistance to any attempt of changing the electronic state and other corresponding states, e.g., changes in structure or microstructure caused by mechanical and electrochemical actions. Using Cu-Ni alloy as an example, we demonstrate the correlation between the EWF and Young's modulus of the material as well as its hardness. The properties of a material can be modified using elements with appropriate work functions. This is also applicable for tailoring inter-phase boundaries or interfaces.

  10. 2010 Defects in Semiconductors GRC

    SciTech Connect (OSTI)

    Shengbai Zhang

    2011-01-06

    Continuing its tradition of excellence, this Gordon Conference will focus on research at the forefront of the field of defects in semiconductors. The conference will have a strong emphasis on the control of defects during growth and processing, as well as an emphasis on the development of novel defect detection methods and first-principles defect theories. Electronic, magnetic, and optical properties of bulk, thin film, and nanoscale semiconductors will be discussed in detail. In contrast to many conferences, which tend to focus on specific semiconductors, this conference will deal with point and extended defects in a broad range of electronic materials. This approach has proved to be extremely fruitful for advancing fundamental understanding in emerging materials such as wide-band-gap semiconductors, oxides, sp{sup 2} carbon based-materials, and photovoltaic/solar cell materials, and in understanding important defect phenomena such as doping bottleneck in nanostructures and the diffusion of defects and impurities. The program consists of about twenty invited talks and a number of contributed poster sessions. The emphasis should be on work which has yet to be published. The large amount of discussion time provides an ideal forum for dealing with topics that are new and/or controversial.

  11. Self healing of defected graphene

    SciTech Connect (OSTI)

    Chen, Jianhui; Shi, Tuwan; Cai, Tuocheng; Wu, Xiaosong; Yu, Dapeng [School of Physics, Peking University, Beijing 100871 (China) [School of Physics, Peking University, Beijing 100871 (China); State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Peking University, Beijing 100871 (China); Xu, Tao; Sun, Litao [SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing 210096 (China)] [SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing 210096 (China)

    2013-03-11

    For electronics applications, defects in graphene are usually undesirable because of their ability to scatter charge carriers, thereby reduce the carrier mobility. It would be extremely useful if the damage can be repaired. In this work, we employ Raman spectroscopy, X-ray photoemission spectroscopy, transmission electron microscopy, and electrical measurements to study defects in graphene introduced by argon plasma bombardment. We have found that majority of these defects can be cured by a simple thermal annealing process. The self-healing is attributed to recombination of mobile carbon adatoms with vacancies. With increasing level of plasma induced damage, the self-healing becomes less effective.

  12. Investigation of fracture mechanical behavior of nodular cast iron and welded joints with parent-material-like weld metal

    SciTech Connect (OSTI)

    Baer, W.; Pusch, G.

    1995-12-31

    The focus of the investigations was the determination of fracture mechanical characteristics and crack resistance curves of the J-Integral and CTOD concept by application of the partial unloading compliance technique and D.C. potential drop technique (four point bend) under static load. The results show a close correlation between crack initiation values as well as crack resistance curves and graphite morphology parameters determined by means of quantitative microstructural analysis where the influence of the matrix (distance of graphite particles) dominates the crack resistance and fracture performance of ferritic nodular cast iron under consideration of the notch effect of graphite particles. SEM in-situ tensile tests showed that due to a beneficial shielding effect of the strength overmatching parent-material-like weld metal (mis-match ratio M = 1.21), cracks positioned directly in the plane of the fusion line did not deviate into the weld metal in spite of its lower toughness compared to that of the parent material. They also showed an unsymmetrical formation of damage in front of the crack tip.

  13. FRAPCON-2: A Computer Code for the Calculation of Steady State Thermal-Mechanical Behavior of Oxide Fuel Rods

    SciTech Connect (OSTI)

    Berna, G. A; Bohn, M. P.; Rausch, W. N.; Williford, R. E.; Lanning, D. D.

    1981-01-01

    FRAPCON-2 is a FORTRAN IV computer code that calculates the steady state response of light Mater reactor fuel rods during long-term burnup. The code calculates the temperature, pressure, deformation, and tai lure histories of a fuel rod as functions of time-dependent fuel rod power and coolant boundary conditions. The phenomena modeled by the code include (a) heat conduction through the fuel and cladding, (b) cladding elastic and plastic deformation, (c) fuel-cladding mechanical interaction, (d) fission gas release, (e} fuel rod internal gas pressure, (f) heat transfer between fuel and cladding, (g) cladding oxidation, and (h) heat transfer from cladding to coolant. The code contains necessary material properties, water properties, and heat transfer correlations. FRAPCON-2 is programmed for use on the CDC Cyber 175 and 176 computers. The FRAPCON-2 code Is designed to generate initial conditions for transient fuel rod analysis by either the FRAP-T6 computer code or the thermal-hydraulic code, RELAP4/MOD7 Version 2.

  14. Flow in porous media, phase behavior and ultralow interfacial tensions: mechanisms of enhanced petroleum recovery. Final technical report

    SciTech Connect (OSTI)

    Davis, H.T.; Scriven, L.E.

    1982-01-01

    A major program of university research, longer-ranged and more fundamental in approach than industrial research, into basic mechanisms of enhancing petroleum recovery and into underlying physics, chemistry, geology, applied mathematics, computation, and engineering science has been built at Minnesota. The 1982 outputs of the interdisciplinary team of investigators were again ideas, instruments, techniques, data, understanding and skilled people: forty-one scientific and engineering papers in leading journals; four pioneering Ph.D. theses; numerous presentations to scientific and technical meetings, and to industrial, governmental and university laboratories; vigorous program of research visits to and from Minnesota; and two outstanding Ph.D.'s to research positions in the petroleum industry, one to a university faculty position, one to research leadership in a governmental institute. This report summarizes the 1982 papers and theses and features sixteen major accomplishments of the program during that year. Abstracts of all forty-five publications in the permanent literature are appended. Further details of information transfer and personnel exchange with industrial, governmental and university laboratories appear in 1982 Quarterly Reports available from the Department of Energy and are not reproduced here. The Minnesota program continues in 1983, notwithstanding earlier uncertainty about the DOE funding which finally materialized and is the bulk of support. Supplemental grants-in-aid from nine companies in the petroleum industry are important, as are the limited University and departmental contributions. 839 references, 172 figures, 29 tables.

  15. Sequential detection of web defects

    DOE Patents [OSTI]

    Eichel, Paul H. (Albuquerque, NM); Sleefe, Gerard E. (Cedar Crest, NM); Stalker, K. Terry (Albuquerque, NM); Yee, Amy A. (Albuquerque, NM)

    2001-01-01

    A system for detecting defects on a moving web having a sequential series of identical frames uses an imaging device to form a real-time camera image of a frame and a comparitor to comparing elements of the camera image with corresponding elements of an image of an exemplar frame. The comparitor provides an acceptable indication if the pair of elements are determined to be statistically identical; and a defective indication if the pair of elements are determined to be statistically not identical. If the pair of elements is neither acceptable nor defective, the comparitor recursively compares the element of said exemplar frame with corresponding elements of other frames on said web until one of the acceptable or defective indications occur.

  16. Mechanical behavior and electrical conductivity of La1-xCaxCoO3 (x = 0, 0.2, 0.4, 0.55) perovskites

    SciTech Connect (OSTI)

    Pathak, Siddhartha; Steinmetz, David; Kuebler, Jakob; Payzant, E Andrew; Orlovskaya, Nina

    2010-01-01

    This paper compares the important mechanical properties and the electrical conductivities from room temperature to 800oC of four LaCoO3 based cobaltite compositions with 0, 20, 40 and 55% Ca2+ ions substituted on the A site of the perovskite structure respectively. Ca2+ doped lanthanum cobaltite materials are strong candidates for use as cathodes in lower temperature solid oxide fuel cells operating at or below 800oC. Among these four cobaltite compositions, two (LaCoO3 and La0.8Ca0.2CoO3) were found to be phase pure materials, whereas the remaining two compositions (La0.6Ca0.4CoO3 and La0.45Ca0.55CoO3) contained precipitation of secondary phases such as CaO and Co3O4. The mechanical properties of the four compositions, in terms of Young s modulus, four-point bending strength and fracture toughness measurements, were measured at both room temperature and 800oC. At room temperature, doping with Ca2+ was found to substantially increase the mechanical properties of the cobaltites, whereas at 800oC the pure LaCoO3 composition exhibited higher modulus and strength values than La0.8Ca0.2CoO3. All of the four compositions exhibited ferroelastic behavior, as shown by the hysteresis loops generated during uniaxial load-unload compression tests. Electrical conductivity measurements showed the La0.8Ca0.2CoO3 composition to have the highest conductivity among the four compositions.

  17. Strong NLS SolitonDefect Interactions # Roy H. Goodman #

    E-Print Network [OSTI]

    propose a mechanism of resonant energy transfer to a nonlinear standing wave mode supported by the defect and ex­ plored. The technique involves resonant transfer of energy from traveling waves (gap solitons Jersey Institute of Technology, Newark, NJ 07102 Philip J. Holmes Program in Applied and Computational

  18. Multidimensional Multiphysics Simulation of Nuclear Fuel Behavior

    SciTech Connect (OSTI)

    R. L. Williamson; J. D. Hales; S. R. Novascone; M. R. Tonks; D. R. Gaston; C. J. Permann; D. Andrs; R. C. Martineau

    2012-04-01

    Important aspects of fuel rod behavior, for example pellet-clad mechanical interaction (PCMI), fuel fracture, oxide formation, non- axisymmetric cooling, and response to fuel manufacturing defects, are inherently multidimensional in addition to being complicated multiphysics problems. Many current modeling tools are strictly 2D axisymmetric or even 1.5D. This paper outlines the capabilities of a new fuel modeling tool able to analyze either 2D axisymmetric or fully 3D models. These capabilities include temperature-dependent thermal conductivity of fuel; swelling and densification; fuel creep; pellet fracture; fission gas release; cladding creep; irradiation growth; and gap mechanics (contact and gap heat transfer). The need for multiphysics, multidimensional modeling is then demonstrated through a discussion of results for a set of example problems. The first, a 10-pellet rodlet, demonstrates the viability of the solution method employed. This example highlights the effect of our smeared cracking model and also shows the multidimensional nature of discrete fuel pellet modeling. The second example relies on our multidimensional, multiphysics approach to analyze a missing pellet surface problem. The next example is the analysis of cesium diffusion in a TRISO fuel particle with defects. As a final example, we show a lower-length-scale simulation coupled to a continuum-scale simulation.

  19. 3.22 Mechanical Properties of Materials, Spring 2003

    E-Print Network [OSTI]

    Gibson, Lorna J.

    Phenomenology of mechanical behavior of materials at the macroscopic level. Relationship of mechanical behavior to material structure and mechanisms of deformation and failure. Topics include: elasticity, viscoelasticity, ...

  20. 3.22 Mechanical Properties of Materials, Spring 2004

    E-Print Network [OSTI]

    Gibson, Lorna J.

    Phenomenology of mechanical behavior of materials at the macroscopic level. Relationship of mechanical behavior to material structure and mechanisms of deformation and failure. Topics include: elasticity, viscoelasticity, ...

  1. Large- Q sup 2 behavior of the Higgs mechanism as derived from one-loop diagrams and the renormalization-group equation

    SciTech Connect (OSTI)

    Huang, C.; Hwang, W.P. (Department of Physics, National Taiwan University, Taipei, Taiwan 10764 (Republic of China))

    1991-12-01

    The renormalization-group (RG) approach generalized by Lee and Weisberger to the case of gauge theories with spontaneous symmetry breaking is adopted in order to study the large-{ital Q}{sup 2} behavior of the Higgs mechanism. The approach amounts to a generalization of the well-known concept of running coupling constants'' to all the couplings involved in the theory. To simplify our consideration, we have considered scalar electrodynamics (QED) in which a U(1) gauge field interacts with both fermions and scalar fields (the latter responsible for spontaneous symmetry breaking). We first carry out a perturbative calculation including all one-loop diagrams with the explicit results on the various renormalization constants obtained by separating out pole parts ({proportional to}1/{epsilon}) of the various diagrams regulated in the dimensional-regularization scheme. Using the explicit results on the renormalization constants, we extract the {beta} and {gamma} functions which govern the behavior of the theory through the RG equation as {ital Q}{sup 2}{r arrow}{infinity}. We then solve explicitly the coupled RG equations, obtaining the result that the vacuum expectation value {ital v}{sup 2}({ital Q}{sup 2}) vanishes as {ital Q}{sup 2}{r arrow}{infinity} (i.e., the broken symmetry is restored) but the gauge sector (consisting of the gauge field and fermions) does not decouple from the strongly self-interacting Higgs sector. In the case of non-Abelian gauge theories, we suggest looking for theories which allow for an eventual decoupling between the strongly interacting Higgs sector and the asymptotically free gauge sector.

  2. Fission products in nuclear fuels pellets can affect fuel performance as they change the fuel chemistry and structure. The behavior of the fission products and their release mechanisms are important to the operation

    E-Print Network [OSTI]

    boundary (GB) at low burnups. Early fission gas release models, which assumed spherical grains chemistry and structure. The behavior of the fission products and their release mechanisms are important to the operation of a power reactor. Research has shown that fission product release can occur through grain

  3. Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

    SciTech Connect (OSTI)

    Masashi Shimada; M. Hara; T. Otsuka; Y. Oya; Y. Hatano

    2014-05-01

    Accurately estimating tritium retention in plasma facing components (PFCs) and minimizing its uncertainty are key safety issues for licensing future fusion power reactors. D-T fusion reactions produce 14.1 MeV neutrons that activate PFCs and create radiation defects throughout the bulk of the material of these components. Recent studies show that tritium migrates and is trapped in bulk (>> 10 µm) tungsten beyond the detection range of nuclear reaction analysis technique [1-2], and thermal desorption spectroscopy (TDS) technique becomes the only established diagnostic that can reveal hydrogen isotope behavior in in bulk (>> 10 µm) tungsten. Radiation damage and its recovery mechanisms in neutron-irradiated tungsten are still poorly understood, and neutron-irradiation data of tungsten is very limited. In this paper, systematic investigations with repeated plasma exposures and thermal desorption are performed to study defect annealing and thermal desorption of deuterium in low dose neutron-irradiated tungsten. Three tungsten samples (99.99 at. % purity from A.L.M.T. Co., Japan) irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to high flux (ion flux of (0.5-1.0)x1022 m-2s-1 and ion fluence of 1x1026 m-2) deuterium plasma at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy (TDS) was performed with a ramp rate of 10 °C/min up to 900 °C, and the samples were annealed at 900 °C for 0.5 hour. These procedures were repeated three (for 100 and 200 °C samples) and four (for 500 °C sample) times to uncover damage recovery mechanisms and its effects on deuterium behavior. The results show that deuterium retention decreases approximately 90, 75, and 66 % for 100, 200, and 500 °C, respectively after each annealing. When subjected to the same TDS recipe, the desorption temperature shifts from 800 °C to 600 °C after 1st annealing for the sample exposed to TPE at 500 °C. Tritium Migration Analysis Program (TMAP) analysis reveals that the detrapping energy decreases from 1.8 eV to 1.4 eV, indicating the changes in trapping mechanisms. This paper also summarizes deuterium behavior studies in HFIR neutron-irradiated tungsten under US-Japan TITAN program.

  4. Mechanical Behavior of Indium Nanostructures

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

    (PMMA) resist with electron-beam lithography, followed by selective metal electroplating into the resist template. This approach is advantageous for low-melting-temperatur...

  5. Mechanical behavior of ultrastructural biocomposites

    E-Print Network [OSTI]

    Kearney, Cathal (Cathal John)

    2006-01-01

    For numerous centuries nature has successfully developed biocomposite materials with detailed multiscale architectures to provide a material stiffness, strength and toughness. One such example is nacre, which is found in ...

  6. Mechanical Behavior of Indium Nanostructures

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

    Indium Under the Nanoscope In this work, Lee et al. investigated the small-scale plastic deformation of indium nanopillars, a previously unstudied material and crystal...

  7. Mechanical Behavior of Indium Nanostructures

    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 wouldMass map shines light on dark matter By SarahMODELING CLOUD1

  8. Structure, defects, and strain in silicon-silicon oxide interfaces

    SciTech Connect (OSTI)

    Kova?evi?, Goran Pivac, Branko

    2014-01-28

    The structure of the interfaces between silicon and silicon-oxide is responsible for proper functioning of MOSFET devices while defects in the interface can deteriorate this function and lead to their failure. In this paper we modeled this interface and characterized its defects and strain. MD simulations were used for reconstructing interfaces into a thermodynamically stable configuration. In all modeled interfaces, defects were found in the form of three-coordinated silicon atom, five coordinated silicon atom, threefold-coordinated oxygen atom, or displaced oxygen atom. Three-coordinated oxygen atom can be created if dangling bonds on silicon are close enough. The structure and stability of three-coordinated silicon atoms (P{sub b} defect) depend on the charge as well as on the electric field across the interface. The negatively charged P{sub b} defect is the most stable one, but the electric field resulting from the interface reduces that stability. Interfaces with large differences in periodic constants of silicon and silicon oxide can be stabilized by buckling of silicon layer. The mechanical stress resulted from the interface between silicon and silicon oxide is greater in the silicon oxide layer. Ab initio modeling of clusters representing silicon and silicon oxide shows about three time larger susceptibility to strain in silicon oxide than in silicon if exposed to the same deformation.

  9. An investigation of defect detection using random defect excitation and deterministic defect observation in complex integrated logic circuits 

    E-Print Network [OSTI]

    Dworak, Jennifer

    2013-02-22

    aWhenever integrated circuits are manufactured, a certain percentage of those circuits will be defective. Defective circuits present problems for both the manufacturers who wish to maintain a good reputation with their customers and the consumers...

  10. MESOSCALE DESCRIPTION OF DEFECTED MATERIALS

    E-Print Network [OSTI]

    Vinals, Jorge

    MESOSCALE DESCRIPTION OF DEFECTED MATERIALS Jorge Vi~nals School of Physics and Astronomy. Laughlin) Small but finite wavenumber and finite frequency ("mesoscale") response functions and transport;MESOSCALE DESCRIPTION B B B B B B B A B A B A A B B A A A A BB A B Microscopic Mesoscopic Macroscopic vn

  11. Defects in Crystals Faizan Nazar

    E-Print Network [OSTI]

    Sengun, Mehmet Haluk

    that are close to the defect. Figure : A 2D sketch of a perfect lattice and a lattice which has been re researchers are also into looking into new materials like graphene), but manufacturers also introduce. The new material is called a semiconductor. There are two types of doping, called p-type and n-type, short

  12. Energetics of Defects on Graphene through Fluorination

    SciTech Connect (OSTI)

    Xiao, Jie; Meduri, Praveen; Chen, Honghao; Wang, Zhiguo; Gao, Fei; Hu, Jian Z.; Feng, Ju; Hu, Mary Y.; Dai, Sheng; Brown, Suree; Adcock, Jamie L.; Deng, Zhiqun; Liu, Jun; Graff, Gordon L.; Aksay, Ilhan A.; Zhang, Jiguang

    2014-04-01

    In the present study, we used FGS[5] as the substrate and implemented low temperature (<=150 oC) direct fluorination on graphene sheets. The fluorine content has been modulated to investigate the formation mechanism of different functional groups such as C-F, CF2, O-CF2 and (C=O)F during the fluorination process. The detailed structure and chemical bonds were simulated theoretically and quantified experimentally by using density function theory (DFT) calculations and NMR techniques, respectively. The adjustable power/energy ratio from fluorinated graphene as cathode for primary lithium batteries is also discussed. From a combination of NMR spectroscopy and theoretical calculation, we conclude that the topological defects without oxygen containing groups provide most of the reactive sites to react with F. FGS also contain a small number of COOH groups which contribute for the fluorination reaction. Hydroxyl or epoxy groups contribute to another fraction of the reaction products.

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

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

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

    2015-03-13

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

  14. Inspection of lithographic mask blanks for defects

    DOE Patents [OSTI]

    Sommargren, Gary E. (Santa Cruz, CA)

    2001-01-01

    A visible light method for detecting sub-100 nm size defects on mask blanks used for lithography. By using optical heterodyne techniques, detection of the scattered light can be significantly enhanced as compared to standard intensity detection methods. The invention is useful in the inspection of super-polished surfaces for isolated surface defects or particulate contamination and in the inspection of lithographic mask or reticle blanks for surface defects or bulk defects or for surface particulate contamination.

  15. Tracking Defect Warnings Across Versions Jaime Spacco

    E-Print Network [OSTI]

    Hovemeyer, David H.

    the results of tracking defect warnings across Sun's Java runtime library. Categories and Subject DescriptorsTracking Defect Warnings Across Versions Jaime Spacco£ , David HovemeyerÝ , William Pugh£ £ Dept of reasons, it is important to be able to track the occurrence of each potential defect over multiple

  16. Optics near an hyperbolic defect

    E-Print Network [OSTI]

    Fumeron, Sébastien; Santos, Fernando; Pereira, Erms; Moraes, Fernando

    2015-01-01

    We examine the properties of a new family of defects called hyperbolic disclinations, and discuss their possible use for the design of perfect optical absorbers. In hyperbolic metamaterials, the ratio of ordinary and extraordinary permittivities is negative, which leads to an effective metric of Kleinian signature (two timelike coordinates). Considering a disclination in the hyperbolic nematic host matrix, we show that the timelike geodesics are Poinsot spirals, i.e. whatever the impact parameter of an incident light beam, it is confined and whirls about the defect core. The trapping effect does not require light to be coherent. This property also remains in the wave formalism, which may be the sign for many potential applications.

  17. Computer code for the atomistic simulation of lattice defects and dynamics. [COMENT code

    SciTech Connect (OSTI)

    Schiffgens, J.O.; Graves, N.J.; Oster, C.A.

    1980-04-01

    This document has been prepared to satisfy the need for a detailed, up-to-date description of a computer code that can be used to simulate phenomena on an atomistic level. COMENT was written in FORTRAN IV and COMPASS (CDC assembly language) to solve the classical equations of motion for a large number of atoms interacting according to a given force law, and to perform the desired ancillary analysis of the resulting data. COMENT is a dual-purpose intended to describe static defect configurations as well as the detailed motion of atoms in a crystal lattice. It can be used to simulate the effect of temperature, impurities, and pre-existing defects on radiation-induced defect production mechanisms, defect migration, and defect stability.

  18. Conformal nets III: fusion of defects

    E-Print Network [OSTI]

    Arthur Bartels; Christopher L. Douglas; André Henriques

    2015-02-21

    Conformal nets provides a mathematical model for conformal field theory. We define a notion of defect between conformal nets, formalizing the idea of an interaction between two conformal field theories. We introduce an operation of fusion of defects, and prove that the fusion of two defects is again a defect, provided the fusion occurs over a conformal net of finite index. There is a notion of sector (or bimodule) between two defects, and operations of horizontal and vertical fusion of such sectors. Our most difficult technical result is that the horizontal fusion of the vacuum sectors of two defects is isomorphic to the vacuum sector of the fused defect. Equipped with this isomorphism, we construct the basic interchange isomorphism between the horizontal fusion of two vertical fusions and the vertical fusion of two horizontal fusions of sectors.

  19. Implementation of density functional embedding theory within the projector-augmented-wave method and applications to semiconductor defect states

    E-Print Network [OSTI]

    Florian, Libisch

    an accurate and efficient way to study properties of iso- lated defects in semiconductors. C 2015 AIP types of solid state materials and play important roles in engineering material properties. The presence of defects significantly affects the chemical, electrical, optical, and mechanical properties of the material

  20. Internal hydriding in irradiated defected Zircaloy fuel rods: A review (LWBR Development Program)

    SciTech Connect (OSTI)

    Clayton, J C

    1987-10-01

    Although not a problem in recent commercial power reactors, including the Shippingport Light Water Breeder Reactor, internal hydriding of Zircaloy cladding was a persistent cause of gross cladding failures during the 1960s. It occurred in the fuel rods of water-cooled nuclear power reactors that had a small cladding defect. This report summarizes the experimental findings, causes, mechanisms, and methods of minimizing internal hydriding in defected Zircaloy-clad fuel rods. Irradiation test data on the different types of defected fuel rods, intentionally fabricated defected and in-pile operationally defected rods, are compared. Significant factors affecting internal hydriding in defected Zircaloy-clad fuel rods (defect hole size, internal and external sources of hydrogen, Zircaloy cladding surface properties, nickel alloy contamination of Zircaloy, the effect of heat flux and fluence) are discussed. Pertinent in-pile and out-of-pile test results from Bettis and other laboratories are used as a data base in constructing a qualitative model which explains hydrogen generation and distribution in Zircaloy cladding of defected water-cooled reactor fuel rods. Techniques for minimizing internal hydride failures in Zircaloy-clad fuel rods are evaluated.

  1. Characterization of V-shaped defects in 4H-SiC homoepitaxial layers

    SciTech Connect (OSTI)

    Zhang, Lihua; Su, Dong; Kisslinger, Kim; Stach, Eric; Chung, Gil; Zhang, Jie; Thomas, Bernd; Sanchez, Edward K; Mueller, Stephan G.; Hansen, Darren; Loboda, Mark J.; Wu, Fangzhen; Wang, Huanhuan; Raghothamachar, Balaji; Dudley, Michael

    2014-12-04

    Synchrotron white beam x-ray topography images show that faint needle-like surface morphological features observed on the Si-face of 4H-SiC homoepitaxial layers using Nomarski optical microscopy are associated with V shaped stacking faults in the epilayer. KOH etching of the V shaped defect reveals small oval pits connected by a shallow line which corresponding to the surface intersections of two partial dislocations and the stacking fault connecting them. Transmission electron microscopy (TEM) specimens from regions containing the V shaped defects were prepared using focused ion beam milling, and stacking sequences of (85), (50) and (63) are observed at the faulted region with high resolution TEM. In order to study the formation mechanism of V shaped defect, low dislocation density 4H-SiC substrates were chosen for epitaxial growth, and the corresponding regions before and after epitaxy growth are compared in SWBXT images. It is found that no defects in the substrate are directly associated with the formation of the V shaped defect. Simulation results of the contrast from the two partial dislocations associated with V shaped defect in synchrotron monochromatic beam x-ray topography reveals the opposite sign nature of their Burgers vectors. Therefore, a mechanism of 2D nucleation during epitaxy growth is postulated for the formation of the V shaped defect, which requires elimination of non-sequential 1/4[0001] bilayers from the original structure to create the observed faulted stacking sequence.

  2. Characterization of V-shaped defects in 4H-SiC homoepitaxial layers

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

    Zhang, Lihua; Su, Dong; Kisslinger, Kim; Stach, Eric; Chung, Gil; Zhang, Jie; Thomas, Bernd; Sanchez, Edward K; Mueller, Stephan G.; Hansen, Darren; et al

    2014-12-04

    Synchrotron white beam x-ray topography images show that faint needle-like surface morphological features observed on the Si-face of 4H-SiC homoepitaxial layers using Nomarski optical microscopy are associated with V shaped stacking faults in the epilayer. KOH etching of the V shaped defect reveals small oval pits connected by a shallow line which corresponding to the surface intersections of two partial dislocations and the stacking fault connecting them. Transmission electron microscopy (TEM) specimens from regions containing the V shaped defects were prepared using focused ion beam milling, and stacking sequences of (85), (50) and (63) are observed at the faulted regionmore »with high resolution TEM. In order to study the formation mechanism of V shaped defect, low dislocation density 4H-SiC substrates were chosen for epitaxial growth, and the corresponding regions before and after epitaxy growth are compared in SWBXT images. It is found that no defects in the substrate are directly associated with the formation of the V shaped defect. Simulation results of the contrast from the two partial dislocations associated with V shaped defect in synchrotron monochromatic beam x-ray topography reveals the opposite sign nature of their Burgers vectors. Therefore, a mechanism of 2D nucleation during epitaxy growth is postulated for the formation of the V shaped defect, which requires elimination of non-sequential 1/4[0001] bilayers from the original structure to create the observed faulted stacking sequence.« less

  3. 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

  4. Graphene defect formation by extreme ultraviolet generated photoelectrons

    SciTech Connect (OSTI)

    Gao, A., E-mail: a.gao@utwente.nl; Lee, C. J.; Bijkerk, F. [FOM-Dutch Institute for Fundamental Energy Research, Edisonbaan 14, 3439 MN Nieuwegein, The Netherlands and XUV Optics Group, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede (Netherlands)

    2014-08-07

    We have studied the effect of photoelectrons on defect formation in graphene during extreme ultraviolet (EUV) irradiation. Assuming the major role of these low energy electrons, we have mimicked the process by using low energy primary electrons. Graphene is irradiated by an electron beam with energy lower than 80?eV. After e-beam irradiation, it is found that the D peak, I(D), appears in the Raman spectrum, indicating defect formation in graphene. The evolution of I(D)/I(G) follows the amorphization trajectory with increasing irradiation dose, indicating that graphene goes through a transformation from microcrystalline to nanocrystalline and then further to amorphous carbon. Further, irradiation of graphene with increased water partial pressure does not significantly change the Raman spectra, which suggests that, in the extremely low energy range, e-beam induced chemical reactions between residual water and graphene are not the dominant mechanism driving defect formation in graphene. Single layer graphene, partially suspended over holes was irradiated with EUV radiation. By comparing with the Raman results from e-beam irradiation, it is concluded that the photoelectrons, especially those from the valence band, contribute to defect formation in graphene during irradiation.

  5. http://journals.cambridge.org Downloaded: 24 Feb 2014 IP address: 128.100.48.236 Characterizing mechanical behavior of atomically thin

    E-Print Network [OSTI]

    Sun, Yu

    applications to composite materials,2­4 lubricants,5,6 electronics,7­9 batteries,10­12 optics,13,14 as well. Mechanical exfoliation Mechanically exfoliating graphite using scotch tape to produce graphene films of graphite Oxidizing graphite to form graphite oxide or starting with expandable graphite or graphite

  6. Simulation of the Manufacturing of Non-Crimp Fabric-Reinforced Composite Wind Turbine Blades to Predict the Formation of Wave Defects

    SciTech Connect (OSTI)

    Fetfatsidis, K. A.; Sherwood, J. A. [Department of Mechanical Engineering, University of Massachusetts, Lowell One University Ave., Lowell, MA 01854 (United States)

    2011-05-04

    NCFs (Non-Crimp Fabrics) are commonly used in the design of wind turbine blades and other complex systems due to their ability to conform to complex shapes without the wrinkling that is typically experienced with woven fabrics or prepreg tapes. In the current research, a form of vacuum assisted resin transfer molding known as SCRIMP registered is used to manufacture wind turbine blades. Often, during the compacting of the fabric layers by the vacuum pressure, several plies may bunch together out-of-plane and form wave defects. When the resin is infused, the areas beneath the waves become resin rich and can compromise the structural integrity of the blade. A reliable simulation tool is valuable to help predict where waves and other defects may appear as a result of the manufacturing process. Forming simulations often focus on the in-plane shearing and tensile behavior of fabrics and do not necessarily consider the bending stiffness of the fabrics, which is important to predict the formation of wrinkles and/or waves. This study incorporates experimentally determined in-plane shearing, tensile, and bending stiffness information of NCFs into a finite element model (ABAQUS/Explicit) of a 9-meter wind turbine blade to investigate the mechanical behaviors that can lead to the formation of waves as a result of the manufacturing process.

  7. Exploring the eddy current excitation invariance to infer about defect characteristics

    SciTech Connect (OSTI)

    Ribeiro, A. Lopes; Ramos, H. G. [I and M Group, Instituto de Telecomunicacoes, Lisboa, Portugal Instituto Superior Tecnico, DEEC, Lisboa (Portugal)

    2011-06-23

    This paper explores the excitation probe excitation field invariance when the eddy current method is applied to detect, localize and characterize material defects in conductive nonmagnetic media. The cases relative to rotational symmetry in circular solenoidal probes and translation symmetry in constant field probes are presented. The experimental data shows that this theoretical treatment is useful to preview the behavior of these probes.

  8. Elastic properties of vanadium pentoxide aggregates and topological defects

    E-Print Network [OSTI]

    L. V. Elnikova

    2008-11-07

    We study the aqueous solution of vanadium pentoxide by using topology methods. The experiments by Zocher, Kaznacheev, and Dogic exhibited, that in the sol phases of $V_2O_5-H_2O$, the tactoid droplets of $V_2O_5$ can coalesce. In the magnetic field, this effect is associated with a gauge field action, viz. we consider coalescence (in the topologically more convenient term, "junction") of droplets as annihilation of topological defects, concerning with the tactoid geometry. We have shown, that in the magnetic field, the tactoid junction is mainly caused by non-Abelian monopoles (vortons), whereas the Abelian defects almost do not annihilate. Taking into account this annihilation mechanism, the estimations of time-aging of the $V_2O_5-H_2O$ sols may be specified

  9. Intracellular transport driven by cytoskeletal motors: General mechanisms and defects

    E-Print Network [OSTI]

    Appert-Rolland, Cecile; Santen, Ludger

    2015-01-01

    Cells are strongly out-of-equilibrium systems driven by continuous energy supply. They carry out many vital functions requiring active transport of various ingredients and organelles, some being small, others being large. The cytoskeleton, composed of three types of filaments, determines the shape of the cell and plays a role in cell motion. It also serves as a road network for the so-called cytoskeletal motors. These molecules can attach to a cytoskeletal filament, perform directed motion, possibly carrying along some cargo, and then detach. It is a central issue to understand how intracellular transport driven by molecular motors is regulated, in particular because its breakdown is one of the signatures of some neuronal diseases like the Alzheimer. We give a survey of the current knowledge on microtubule based intracellular transport. We first review some biological facts obtained from experiments, and present some modeling attempts based on cellular automata. We start with background knowledge on the origi...

  10. Intracellular transport driven by cytoskeletal motors: General mechanisms and defects

    E-Print Network [OSTI]

    Cecile Appert-Rolland; Maximilian Ebbinghaus; Ludger Santen

    2015-07-22

    Cells are strongly out-of-equilibrium systems driven by continuous energy supply. They carry out many vital functions requiring active transport of various ingredients and organelles, some being small, others being large. The cytoskeleton, composed of three types of filaments, determines the shape of the cell and plays a role in cell motion. It also serves as a road network for the so-called cytoskeletal motors. These molecules can attach to a cytoskeletal filament, perform directed motion, possibly carrying along some cargo, and then detach. It is a central issue to understand how intracellular transport driven by molecular motors is regulated, in particular because its breakdown is one of the signatures of some neuronal diseases like the Alzheimer. We give a survey of the current knowledge on microtubule based intracellular transport. We first review some biological facts obtained from experiments, and present some modeling attempts based on cellular automata. We start with background knowledge on the original and variants of the TASEP (Totally Asymmetric Simple Exclusion Process), before turning to more application oriented models. After addressing microtubule based transport in general, with a focus on in vitro experiments, and on cooperative effects in the transportation of large cargos by multiple motors, we concentrate on axonal transport, because of its relevance for neuronal diseases. It is a challenge to understand how this transport is organized, given that it takes place in a confined environment and that several types of motors moving in opposite directions are involved. We review several features that could contribute to the efficiency of this transport, including the role of motor-motor interactions and of the dynamics of the underlying microtubule network. Finally, we discuss some still open questions.

  11. CASTING DEFECT MODELING IN AN INTEGRATED COMPUTATIONAL MATERIALS ENGINEERING APPROACH

    SciTech Connect (OSTI)

    Sabau, Adrian S [ORNL

    2015-01-01

    To accelerate the introduction of new cast alloys, the simultaneous modeling and simulation of multiphysical phenomena needs to be considered in the design and optimization of mechanical properties of cast components. The required models related to casting defects, such as microporosity and hot tears, are reviewed. Three aluminum alloys are considered A356, 356 and 319. The data on calculated solidification shrinkage is presented and its effects on microporosity levels discussed. Examples are given for predicting microporosity defects and microstructure distribution for a plate casting. Models to predict fatigue life and yield stress are briefly highlighted here for the sake of completion and to illustrate how the length scales of the microstructure features as well as porosity defects are taken into account for modeling the mechanical properties. Thus, the data on casting defects, including microstructure features, is crucial for evaluating the final performance-related properties of the component. ACKNOWLEDGEMENTS This work was performed under a Cooperative Research and Development Agreement (CRADA) with the Nemak Inc., and Chrysler Co. for the project "High Performance Cast Aluminum Alloys for Next Generation Passenger Vehicle Engines. The author would also like to thank Amit Shyam for reviewing the paper and Andres Rodriguez of Nemak Inc. Research sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office, as part of the Propulsion Materials Program under contract DE-AC05-00OR22725 with UT-Battelle, LLC. Part of this research was conducted through the Oak Ridge National Laboratory's High Temperature Materials Laboratory User Program, which is sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program.

  12. Shedding Light on Nanocrystal Defects

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

    lately, given their various advantageous mechanical properties. Their resistance to stress has had researchers proposing nanocrystals as a promising new protective coating for...

  13. Predicting the equilibria of point defects in zirconium oxide : a route to understand the corrosion and hydrogen pickup of zirconium alloys

    E-Print Network [OSTI]

    Youssef, Mostafa Youssef Mahmoud

    2014-01-01

    The performance of zirconium alloys in nuclear reactors is compromised by corrosion and hydrogen pickup. The thermodynamics and kinetics of these two processes are governed by the behavior of point defects in the ZrO? layer ...

  14. Energy levels and decoherence properties of single electron and nuclear spins in a defect center in diamond

    E-Print Network [OSTI]

    I. Popa; T. Gaebel; M. Domhan; C. Wittmann; F. Jelezko; J. Wrachtrup

    2004-09-12

    The coherent behavior of the single electron and single nuclear spins of a defect center in diamond and a 13C nucleus in its vicinity, respectively, are investigated. The energy levels associated with the hyperfine coupling of the electron spin of the defect center to the 13C nuclear spin are analyzed. Methods of magnetic resonance together with optical readout of single defect centers have been applied in order to observe the coherent dynamics of the electron and nuclear spins. Long coherence times, in the order of microseconds for electron spins and tens of microseconds for nuclear spins, recommend the studied system as a good experimental approach for implementing a 2-qubit gate.

  15. 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

  16. Evaluation of the thermal-hydraulic response and fuel rod thermal and mechanical deformation behavior during the power burst facility test LOC-3. [PWR

    SciTech Connect (OSTI)

    Yackle, T.R.; MacDonald, P.E.; Broughton, J.M.

    1980-01-01

    An evaluation of the results from the LOC-3 nuclear blowdown test conducted in the Power Burst Facility is presented. The test objective was to examine fuel and cladding behavior during a postulated cold leg break accident in a pressurized water reactor (PWR). Separate effects of rod internal pressure and the degree of irradiation were investigated in the four-rod test. Extensive cladding deformation (ballooning) and failure occurred during blowdown. The deformation of the low and high pressure rods was similar; however, the previously irradiated test rod deformed to a greater extent than a similar fresh rod exposed to identical system conditions.

  17. Coulomb screening in graphene with topological defects

    E-Print Network [OSTI]

    Baishali Chakraborty; Kumar S. Gupta; Siddhartha Sen

    2015-02-20

    We analyze the screening of an external Coulomb charge in gapless graphene cone, which is taken as a prototype of a topological defect. In the subcritical regime, the induced charge is calculated using both the Green's function and the Friedel sum rule. The dependence of the polarization charge on the Coulomb strength obtained from the Green's function clearly shows the effect of the conical defect and indicates that the critical charge itself depends on the sample topology. Similar analysis using the Friedel sum rule indicates that the two results agree for low values of the Coulomb charge but differ for the higher strengths, especially in the presence of the conical defect. For a given subcritical charge, the transport cross-section has a higher value in the presence of the conical defect. In the supercritical regime we show that the coefficient of the power law tail of polarization charge density can be expressed as a summation of functions which vary log periodically with the distance from the Coulomb impurity. The period of variation depends on the conical defect. In the presence of the conical defect, the Fano resonances begin to appear in the transport cross-section for a lower value of the Coulomb charge. For both sub and supercritical regime we derive the dependence of LDOS on the conical defect. The effects of generalized boundary condition on the physical observables are also discussed.

  18. Symmetry fractionalization and twist defects

    E-Print Network [OSTI]

    Nicolas Tarantino; Netanel Lindner; Lukasz Fidkowski

    2015-06-22

    Topological order in two dimensions can be described in terms of deconfined quasiparticle excitations - anyons - and their braiding statistics. However, it has recently been realized that this data does not completely describe the situation in the presence of an unbroken global symmetry. In this case, there can be multiple distinct quantum phases with the same anyons and statistics, but with different patterns of symmetry fractionalization - termed symmetry enriched topological (SET) order. When the global symmetry group $G$, which we take to be discrete, does not change topological superselection sectors - i.e. does not change one type of anyon into a different type of anyon - one can imagine a local version of the action of $G$ around each anyon. This leads to projective representations and a group cohomology description of symmetry fractionalization, with $H^2(G,{\\cal A})$ being the relevant group. In this paper, we treat the general case of a symmetry group $G$ possibly permuting anyon types. We show that despite the lack of a local action of $G$, one can still make sense of a so-called twisted group cohomology description of symmetry fractionalization, and show how this data is encoded in the associativity of fusion rules of the extrinsic `twist' defects of the symmetry. Furthermore, building on work of Hermele, we construct a wide class of exactly solved models which exhibit this twisted symmetry fractionalization, and connect them to our formal framework.

  19. Defect Analysis of Vehicle Compressed Natural Gas Composite Cylinder...

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

    Defect Analysis of Vehicle Compressed Natural Gas Composite Cylinder Defect Analysis of Vehicle Compressed Natural Gas Composite Cylinder These slides were presented at the Onboard...

  20. Characterization of structural defects in nuclear graphite IG...

    Office of Scientific and Technical Information (OSTI)

    Characterization of structural defects in nuclear graphite IG-110 and NBG-18 Citation Details In-Document Search Title: Characterization of structural defects in nuclear graphite...

  1. Di-interstitial defect in silicon revisited

    SciTech Connect (OSTI)

    Londos, C. A.; Antonaras, G.; Chroneos, A.; Department of Materials, Imperial College London, London SW7 2BP

    2013-11-21

    Infrared spectroscopy was used to study the defect spectrum of Cz-Si samples following fast neutron irradiation. We mainly focus on the band at 533 cm{sup ?1}, which disappears from the spectra at ?170 °C, exhibiting similar thermal stability with the Si-P6 electron paramagnetic resonance (EPR) spectrum previously correlated with the di-interstitial defect. The suggested structural model of this defect comprises of two self-interstitial atoms located symmetrically around a lattice site Si atom. The band anneals out following a first-order kinetics with an activation energy of 0.88 ± 0.3 eV. This value does not deviate considerably from previously quoted experimental and theoretical values for the di-interstitial defect. The present results indicate that the 533 cm{sup ?1} IR band originates from the same structure as that of the Si-P6 EPR spectrum.

  2. Thermodynamics of Cosmic Defect Network Evolution

    E-Print Network [OSTI]

    Avelino, P P

    2015-01-01

    We show that simple thermodynamic conditions determine, to a great extent, the equation of state and dynamics of cosmic defects of arbitrary dimensionality. We use these conditions to provide a more direct derivation of the Velocity-dependent One-Scale (VOS) model for the macroscopic dynamics of topological defects of arbitrary dimensionality in a $N+1$-dimensional homogeneous and isotropic universe. We parameterize the modifications to the VOS model associated to the interaction of the topological defects with other fields, including, in particular, a new dynamical degree of freedom associated to the variation of the mass per unit $p$-area of the defects, and compute the corresponding scaling solutions. The observational impact of this new dynamical degree of freedom is also briefly discussed.

  3. DEPARTMENT OF CHEMICAL ENGINEERING DEPARTMENT OF MECHANICAL AND INDUSTRIAL ENGINEERING

    E-Print Network [OSTI]

    Mountziaris, T. J.

    DEPARTMENT OF CHEMICAL ENGINEERING DEPARTMENT OF MECHANICAL AND INDUSTRIAL ENGINEERING University aims at a comprehensive introduction to the mechanical behavior of solid engineering materials utilized. Understanding of the mechanical behavior of solid engineering materials used in current materials engineering

  4. Revealing origin of quasi-one dimensional current transport in defect rich two dimensional materials

    SciTech Connect (OSTI)

    Lotz, Mikkel R.; Boll, Mads; Bøggild, Peter; Petersen, Dirch H., E-mail: dirch.petersen@nanotech.dtu.dk [Center for Nanostructured Graphene (CNG), Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark); Hansen, Ole [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark); Danish National Research Foundation's Center for Individual Nanoparticle Functionality (CINF), Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Kjær, Daniel [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark); CAPRES A/S, Scion-DTU, Building 373, DK-2800 Kgs. Lyngby (Denmark)

    2014-08-04

    The presence of defects in graphene have for a long time been recognized as a bottleneck for its utilization in electronic and mechanical devices. We recently showed that micro four-point probes may be used to evaluate if a graphene film is truly 2D or if defects in proximity of the probe will lead to a non-uniform current flow characteristic of lower dimensionality. In this work, simulations based on a finite element method together with a Monte Carlo approach are used to establish the transition from 2D to quasi-1D current transport, when applying a micro four-point probe to measure on 2D conductors with an increasing amount of line-shaped defects. Clear 2D and 1D signatures are observed at low and high defect densities, respectively, and current density plots reveal the presence of current channels or branches in defect configurations yielding 1D current transport. A strong correlation is found between the density filling factor and the simulation yield, the fraction of cases with 1D transport and the mean sheet conductance. The upper transition limit is shown to agree with the percolation threshold for sticks. Finally, the conductance of a square sample evaluated with macroscopic edge contacts is compared to the micro four-point probe conductance measurements and we find that the micro four-point probe tends to measure a slightly higher conductance in samples containing defects.

  5. INNOVATIVE EDDY CURRENT PROBE FOR MICRO DEFECTS

    SciTech Connect (OSTI)

    Santos, Telmo G.; Vilaca, Pedro; Quintino, Luisa [IDMEC, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Santos, Jorge dos [GKSS, Max-Planck-Street 1, D-21502 Geesthacht (Germany); Rosado, Luis [IST, UTL, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)

    2010-02-22

    This paper reports the development of an innovative eddy current (EC) probe, and its application to micro-defects on the root of the Friction Stir Welding (FSW). The new EC probe presents innovative concept issues, allowing 3D induced current in the material, and a lift-off independence. Validation experiments were performed on aluminium alloys processed by FSW. The results clearly show that the new EC probe is able to detect and sizing surface defects about 60 microns depth.

  6. Reflection and transmission of conformal perturbation defects

    E-Print Network [OSTI]

    Ilka Brunner; Cornelius Schmidt-Colinet

    2015-08-18

    We consider reflection and transmission of interfaces which implement renormalisation group flows between conformal fixed points in two dimensions. Such an RG interface is constructed from the identity defect in the ultraviolet CFT by perturbing the theory on one side of the defect line. We compute reflection and transmission coefficients in perturbation theory to third order in the coupling constant and check our calculations against exact constructions of RG interfaces between coset models.

  7. Reflection and transmission of conformal perturbation defects

    E-Print Network [OSTI]

    Brunner, Ilka

    2015-01-01

    We consider reflection and transmission of interfaces which implement renormalisation group flows between conformal fixed points in two dimensions. Such an RG interface is constructed from the identity defect in the ultraviolet CFT by perturbing the theory on one side of the defect line. We compute reflection and transmission coefficients in perturbation theory to third order in the coupling constant and check our calculations against exact constructions of RG interfaces between coset models.

  8. Atomic-scale electron-beam sculpting of defect-free graphene nanostructures

    E-Print Network [OSTI]

    Dekker, Cees

    Atomic-scale electron-beam sculpting of defect-free graphene nanostructures Bo Song, Grégory F.w.zandbergen@tudelft.nl ABSTRACT. In order to harvest the many promising properties of graphene in (electronic) applications a temperature-dependent self-repair mechanism allowing damage-free atomic-scale sculpting of graphene using

  9. A continuum model for defect dynamics in metallic glasses Amit Acharya

    E-Print Network [OSTI]

    Acharya, Amit

    a fundamental characterization of the process of plastic deformation in a metallic glass, relating its structure and the simplest linear kinetic assumptions arising from enforcing the second law of thermodynamics mechanical model of defect dynamics in metallic glasses that accounts for topological, energetic, and kinetic

  10. 3.225 Electronic and Mechanical Properties of Materials, Summer 2002

    E-Print Network [OSTI]

    Gibson, Lorna J.

    2002-01-01

    Electrical, optical, magnetic, and mechanical properties of metals, semiconductors, ceramics and polymers. Discussion of roles of bonding, structure (crystalline, defect, energy band and microstructure) and composition in ...

  11. Effects of boron-nitride substrates on Stone-Wales defect formation in graphene: An ab initio molecular dynamics study

    SciTech Connect (OSTI)

    Jin, K.; Xiao, H. Y. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Zhang, Y. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Weber, W. J., E-mail: wjweber@utk.edu [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-05-19

    Ab initio molecular dynamics simulations are performed to investigate the effects of a boron nitride (BN) substrate on Stone-Wales (SW) defect formation and recovery in graphene. It is found that SW defects can be created by an off-plane recoil atom that interacts with the BN substrate. A mechanism with complete bond breakage for formation of SW defects in suspended graphene is also revealed for recoils at large displacement angles. In addition, further irradiation can result in recovery of the SW defects through a bond rotation mechanism in both graphene and graphene/BN, and the substrate has little effect on the recovery process. This study indicates that the BN substrate enhances the irradiation resistance of graphene.

  12. Two-dimensional defect modes in optically induced photonic lattices

    SciTech Connect (OSTI)

    Wang Jiandong; Yang Jianke; Chen Zhigang [Department of Mathematics and Statistics, University of Vermont, Burlington, Vermont 05401 (United States); Department of Physics and Astronomy, San Francisco State University, San Francisco, California 94132 (United States)

    2007-07-15

    In this article, localized linear defect modes due to band gap guidance in two-dimensional photonic lattices with localized or nonlocalized defects are investigated theoretically. First, when the defect is localized and weak, eigenvalues of defect modes bifurcated from edges of Bloch bands are derived analytically. It is shown that in an attractive (repulsive) defect, defect modes bifurcate out from Bloch-band edges with normal (anomalous) diffraction coefficients. Furthermore, distances between defect-mode eigenvalues and Bloch-band edges decrease exponentially with the defect strength, which is very different from the one-dimensional case where such distances decrease quadratically with the defect strength. It is also found that some defect-mode branches bifurcate not from Bloch-band edges, but from quasiedge points within Bloch bands, which is very unusual. Second, when the defect is localized but strong, defect modes are determined numerically. It is shown that both the repulsive and attractive defects can support various types of defect modes such as fundamental, dipole, quadrupole, and vortex modes. These modes reside in various band gaps of the photonic lattice. As the defect strength increases, defect modes move from lower band gaps to higher ones when the defect is repulsive, but remain within each band gap when the defect is attractive, similar to the one-dimensional case. The same phenomena are observed when the defect is held fixed while the applied dc field (which controls the lattice potential) increases. Lastly, if the defect is nonlocalized (i.e., it persists at large distances in the lattice), it is shown that defect modes can be embedded inside the continuous spectrum, and they can bifurcate out from edges of the continuous spectrum algebraically rather than exponentially.

  13. Femtosecond-laser Microstructuring of Silicon: Dopants and Defects

    E-Print Network [OSTI]

    Mazur, Eric

    -laser Microstructuring of Silicon: Dopants and Defects Cynthia Friend Michael A. Sheehy Abstract This dissertation deals

  14. Mechanical Engineering "The Lindbergh Lectures"

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    such as surface defects and inferior mechanical properties compared to conventional solid injection molded parts Molding and An Ongoing Journey for Lightweight, Microcellular Plastics Presented by: Lih-Sheng (Tom) Turng of the Cornell Injection Molding Program (CIMP), which was founded in 1974 by Professor K. K. Wang and his

  15. Topological defects in electric double layers of ionic liquids at carbon interfaces

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

    Black, Jennifer M.; Okatan, Mahmut Baris; Feng, Guang; Cummings, Peter T.; Kalinin, Sergei V.; Balke, Nina

    2015-06-07

    The structure and properties of the electrical double layer in ionic liquids is of interest in a wide range of areas including energy storage, catalysis, lubrication, and many more. Theories describing the electrical double layer for ionic liquids have been proposed, however a full molecular level description of the double layer is lacking. To date, studies have been predominantly focused on ion distributions normal to the surface, however the 3D nature of the electrical double layer in ionic liquids requires a full picture of the double layer structure not only normal to the surface, but also in plane. Here wemore »utilize 3D force mapping to probe the in plane structure of an ionic liquid at a graphite interface and report the direct observation of the structure and properties of topological defects. The observation of ion layering at structural defects such as step-edges, reinforced by molecular dynamics simulations, defines the spatial resolution of the method. Observation of defects allows for the establishment of the universality of ionic liquid behavior vs. separation from the carbon surface and to map internal defect structure. In conclusion, these studies offer a universal pathway for probing the internal structure of topological defects in soft condensed matter on the nanometer level in three dimensions.« less

  16. Displacement fields of point defects in two-dimensional colloidal crystals

    E-Print Network [OSTI]

    Wolfgang Lechner; Elisabeth Schöll-Paschinger; Christoph Dellago

    2008-05-20

    Point defects such as interstitials, vacancies, and impurities in otherwise perfect crystals induce complex displacement fields that are of long-range nature. In the present paper we study numerically the response of a two-dimensional colloidal crystal on a triangular lattice to the introduction of an interstitial particle. While far from the defect position the resulting displacement field is accurately described by linear elasticity theory, lattice effects dominate in the vicinity of the defect. In comparing the results of particle based simulations with continuum theory, it is crucial to employ corresponding boundary conditions in both cases. For the periodic boundary condition used here, the equations of elasticity theory can be solved in a consistent way with the technique of Ewald summation familiar from the electrostatics of periodically replicated systems of charges and dipoles. Very good agreement of the displacement fields calculated in this way with those determined in particle simulations is observed for distances of more than about 10 lattice constants. Closer to the interstitial, strongly anisotropic displacement fields with exponential behavior can occur for certain defect configurations. Here we rationalize this behavior with a simple bead-spring that relates the exponential decay constant to the elastic constants of the crystal.

  17. Manufacturing Defects Common to Composite Wind Turbine Blades: Effects of Defects

    E-Print Network [OSTI]

    1 Manufacturing Defects Common to Composite Wind Turbine Blades: Effects of Defects Jared W. Nelson The Blade Reliability Collaborative has been formed to perform comprehensive studies to improve wind turbine uni-directional wind turbine fiber-reinforced composite material with an epoxy resin were utilized

  18. A topological point defect regulates the evolution of extended defects in irradiated silicon

    E-Print Network [OSTI]

    Wilkins, John

    functional theory calculations establish formation energies, activation barriers, and electronic structures structure. Compared to the experimental gap of 1.16 eV for bulk Si,16 the calculated HSE gap, 1.15 eV, shows interstitial defects in irradiated silicon. Molecular dynamics simulations reveal the role of the bond defect

  19. FRAPCON-2: a computer code for the calculation of steady state thermal-mechanical behavior of oxide fuel rods. Technical report

    SciTech Connect (OSTI)

    Berna, G.A.; Bohn, M.P.; Rausch, W.N.; Williford, R.E.; Lanning, D.D.

    1981-01-01

    FRAPCON-2 is a FORTRAN IV computer code that calculates the steady state response of light water reactor fuel rods during long-term burnup. The code calculates the temperature, pressure, deformation, and failure histories of a fuel rod as functions of time-dependent fuel rod power and coolant boundary conditions. The phenomena modeled by the code include: (a) heat conduction through the fuel and cladding, (b) cladding elastic and plastic deformation, (c) fuel-cladding mechanical interaction, (d) fission gas release, (e) fuel rod internal gas pressure, (f) heat transfer between fuel and cladding, (g) cladding oxidation, and (h) heat transfer from cladding to coolant. The code contains necessary material properties, water properties, and heat transfer correlations. FRAPCON-2 is programmed for use on the CDC Cyber 175 and 176 computers. The FRAPCON-2 code is designed to generate initial conditions for transient fuel rod analysis by either the FRAP-T6 computer code or the thermal-hydraulic code, RELAP4/MOD7 Version2.

  20. From Quantum Mechanics to Thermodynamics?

    E-Print Network [OSTI]

    Steinhoff, Heinz-Jürgen

    From Quantum Mechanics to Thermodynamics? Dresden, 22.11.2004 Jochen Gemmer Universit¨at Osnabr to thermodynamical behavior · Quantum approach to thermodynamical behavior · The route to equilibrium · Summary of thermodynamical behavior entirely on the basis of Hamilton models and Schr¨odinger-type quantum dynamics. · define

  1. Polycrystal model of the mechanical behavior of a Mo-TiC30vol.% metal-ceramic composite using a 3D microstructure map obtained by a dual beam FIB-SEM

    E-Print Network [OSTI]

    Cédat, Denis; Rey, Colette; Raabe, Dierk; 10.1016/actamat.2011.11.55

    2013-01-01

    The mechanical behavior of a Mo-TiC30 vol.% ceramic-metal composite was investigated over a large temperature range (25^{\\circ}C to 700^{\\circ}C). High-energy X-ray tomography was used to reveal the percolation of the hard titanium carbide phase through the composite. Using a polycrystal approach for a two-phase material, finite element simulations were performed on a real 3D aggregate of the material. The 3D microstructure, used as starting configuration for the predictions, was obtained by serial-sectioning in a dual beam Focused Ion Beam (FIB)-Scanning Electron Microscope (SEM) coupled to an Electron Back Scattering Diffraction system (3D EBSD, EBSD tomography). The 3D aggregate consists of a molybdenum matrix and a percolating TiC skeleton. As most BCC metals, the molybdenum matrix phase is characterized by a change in the plasticity mechanisms with temperature. We used a polycrystal model for the BCC material, which was extended to two phases (TiC and Mo). The model parameters of the matrix were determin...

  2. Enhanced superconducting properties in Bi{sub 2}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub y} by thermal and mechanical processing

    SciTech Connect (OSTI)

    Miller, D.J.; Holesinger, T.G.; Hettinger, J.D.; Goretta, K.C.; Gray, K.E.

    1992-08-01

    The practical application of high temperature superconductors has been limited by low transport currents in bulk samples. The effect of processing on transition temperature, grain boundary coupling, and flux pinning has been examined for Bi{sub 2}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub y}. Enhancement of {Tc} based on composition can be achieved by control of crystallization and subsequent annealing processes while thermo-mechanical processing may be used to modify weak link and flux pinning behavior. The microstructural basis for these changes are related to the composition of the superconducting phase and the presence of defects associated with deformation processing. The implications of these results on conductor development are related to the selection of alloy composition for optimum transition temperature and controlled thermo-mechanical processing which yields a uniform defect structure.

  3. Hovering Black Holes from Charged Defects

    E-Print Network [OSTI]

    Gary T. Horowitz; Nabil Iqbal; Jorge E. Santos; Benson Way

    2015-05-05

    We construct the holographic dual of an electrically charged, localised defect in a conformal field theory at strong coupling, by applying a spatially dependent chemical potential. We find that the IR behaviour of the spacetime depends on the spatial falloff of the potential. Moreover, for sufficiently localized defects with large amplitude, we find that a new gravitational phenomenon occurs: a spherical extremal charged black hole nucleates in the bulk: a hovering black hole. This is a second order quantum phase transition. We construct this new phase with several profiles for the chemical potential and study its properties. We find an apparently universal behaviour for the entropy of the defect as a function of its amplitude. We comment on the possible field theory implications of our results.

  4. Bistable defect structures in blue phase devices

    E-Print Network [OSTI]

    A. Tiribocchi; G. Gonnella; D. Marenduzzo; E. Orlandini; F. Salvadore

    2011-10-28

    Blue phases (BPs) are liquid crystals made up by networks of defects, or disclination lines. While existing phase diagrams show a striking variety of competing metastable topologies for these networks, very little is known as to how to kinetically reach a target structure, or how to switch from one to the other, which is of paramount importance for devices. We theoretically identify two confined blue phase I systems in which by applying an appropriate series of electric field it is possible to select one of two bistable defect patterns. Our results may be used to realise new generation and fast switching energy-saving bistable devices in ultrathin surface treated BPI wafers.

  5. GaN: Defect and Device Issues

    SciTech Connect (OSTI)

    Pearton, S.J.; Ren, F.; Shul, R.J.; Zolper, J.C.

    1998-11-09

    The role of extended and point defects, and key impurities such as C, O and H, on the electrical and optical properties of GaN is reviewed. Recent progress in the development of high reliability contacts, thermal processing, dry and wet etching techniques, implantation doping and isolation and gate insulator technology is detailed. Finally, the performance of GaN-based electronic and photonic devices such as field effect transistors, UV detectors, laser diodes and light-emitting diodes is covered, along with the influence of process-induced or grown-in defects and impurities on the device physics.

  6. The effects of fastener hole defects 

    E-Print Network [OSTI]

    Andrews, Scot D.

    1991-01-01

    ) August 1991 ABSTRACT The Effects of Fastener Hole Defects. (August 1991) Scot D. Andrews, B. S. , Texas A8rM University Chair of Advisory Committee: Dr. Orden O. Ochoa The influence of drilling-induced defects, such as delamination, on the fatigue... ambient and elevated temperature wet conditions. Specimens were tested in a bearing tension frame to static failure in order to measure the failure load and to calculate pin bearing stress. From static test results, a fatigue load was selected as 66...

  7. Thermal, chemical, and mechanical cookoff modeling

    SciTech Connect (OSTI)

    Hobbs, M.L.; Baer, M.R.; Gross, R.J.

    1994-08-01

    A Thermally Reactive, Elastic-plastic eXplosive code, TREX, has been developed to analyze coupled thermal, chemical and mechanical effects associated with cookoff simulation of confined or unconfined energetic materials. In confined systems, pressure buildup precedes thermal runaway, and unconfined energetic material expands to relieve high stress. The model was developed based on nucleation, decomposition chemistry, and elastic/plastic mechanical behavior of a material with a distribution of internal defects represented as clusters of spherical inclusions. A local force balance, with mass continuity constraints, forms the basis of the model requiring input of temperature and reacted gas fraction. This constitutive material model has been incorporated into a quasistatic mechanics code SANTOS as a material module which predicts stress history associated with a given strain history. The thermal-chemical solver XCHEM has been coupled to SANTOS to provide temperature and reacted gas fraction. Predicted spatial history variables include temperature, chemical species, solid/gas pressure, solid/gas density, local yield stress, and gas volume fraction. One-Dimensional Time to explosion (ODTX) experiments for TATB and PBX 9404 (HMX and NC) are simulated using global multistep kinetic mechanisms and the reactive elastic-plastic constitutive model. Pressure explosions, rather than thermal runaway, result in modeling slow cookoff experiments of confined conventional energetic materials such as TATB. For PBX 9404, pressure explosions also occur at fast cookoff conditions because of low temperature reactions of nitrocellulose resulting in substantial pressurization. A demonstrative calculation is also presented for reactive heat flow in a hollow, propellant-filled, stainless steel cylinder, representing a rocket motor. This example simulation show

  8. The role of primary point defects in the degradation of silicon detectors due to hadron and lepton irradiation

    E-Print Network [OSTI]

    I. Lazanu; S. Lazanu

    2006-03-20

    The principal obstacle to long-time operation of silicon detectors at the highest energies in the next generation of experiments arises from bulk displacement damage which causes significant degradation of their macroscopic properties. The analysis of the behaviour of silicon detectors after irradiation conduces to a good or reasonable agreement between theoretical calculations and experimental data for the time evolution of the leakage current and effective carrier concentration after lepton and gamma irradiation and large discrepancies after hadron irradiation and this in conditions where a reasonable agreement is obtained between experimental and calculated concentrations of complex defects. In this contribution, we argue that the main discrepancies could be solved naturally considering as primary defects the self-interstitials, classical vacancies and the new predicted fourfold coordinated silicon pseudo-vacancy defects. This new defect is supposed to be introduced uniformly in the bulk during irradiation, has deep energy level(s) in the gap and it is stable in time. Considering the mechanisms of production of defects and their kinetics, it was possible to determine indirectly the characteristics of the SiFFCD defect: energy level in the band gap and cross section for minority carrier capture. In the frame of the model, the effects of primary defects on the degradation of silicon detectors are important in conditions of continuous long time irradiation and /or high fluences.

  9. Tuning Interfacial Thermal Conductance of Graphene Embedded in Soft Materials by Vacancy Defects

    SciTech Connect (OSTI)

    Liu, Ying [Clemson University; Hu, Chongze [Clemson University; Huang, Jingsong [ORNL; Sumpter, Bobby G [ORNL; Qiao, Rui [Engineering Science and Mechanics Department, Virginia Tech, Blacksburg, VA, USA

    2015-01-01

    Nanocomposites based on graphene dispersed in matrices of soft materials are promising thermal management materials. Their effective thermal conductivity depends on both the thermal conductivity of graphene and the conductance of the thermal transport across graphene-matrix interfaces. Here we report on molecular dynamics simulations of the thermal transport across the interfaces between defected graphene and soft materials in two different modes: in the across mode, heat enters graphene from one side of its basal plane and leaves through the other side; in the non-across mode, heat enters or leaves a graphene simultaneously from both sides of its basal plane. We show that, as the density of vacancy defects in graphene increases from 0 to 8%, the conductance of the interfacial thermal transport in the across mode increases from 160.4 16 to 207.8 11 MW/m2K, while that in the non-across mode increases from 7.2 0.1 to 17.8 0.6 MW/m2K. The molecular mechanisms for these variations of thermal conductance are clarified by using the phonon density of states and structural characteristics of defected graphenes. On the basis of these results and effective medium theory, we show that it is possible to enhance the effective thermal conductivity of thermal nanocomposites by tuning the density of vacancy defects in graphene despite the fact that graphene s thermal conductivity always decreases as vacancy defects are introduced.

  10. Gauge turbulence, topological defect dynamics, and condensation in Higgs models

    SciTech Connect (OSTI)

    Gasenzer, Thomas; McLerran, Larry; Pawlowski, Jan M.; Sexty, Dénes

    2014-07-28

    The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.

  11. Dark Matter with Topological Defects in the Inert Doublet Model

    E-Print Network [OSTI]

    Mark Hindmarsh; Russell Kirk; Jose Miguel No; Stephen M. West

    2015-07-29

    We examine the production of dark matter by decaying topological defects in the high mass region $m_{\\mathrm{DM}} \\gg m_W$ of the Inert Doublet Model, extended with an extra U(1) gauge symmetry. The density of dark matter states (the neutral Higgs states of the inert doublet) is determined by the interplay of the freeze-out mechanism and the additional production of dark matter states from the decays of topological defects, in this case cosmic strings. These decays increase the predicted relic abundance compared to the standard freeze-out only case, and as a consequence the viable parameter space of the Inert Doublet Model can be widened substantially. In particular, for a given dark matter annihilation rate lower dark matter masses become viable. We investigate the allowed mass range taking into account constraints on the energy injection rate from the diffuse $\\gamma$-ray background and Big Bang Nucleosynthesis, together with constraints on the dark matter properties coming from direct and indirect detection limits. For the Inert Doublet Model high-mass region, an inert Higgs mass as low as $\\sim 200$ GeV is permitted. There is also an upper limit on string mass per unit length, and hence the symmetry breaking scale, from the relic abundance in this scenario. Depending on assumptions made about the string decays, the limits are in the range $10^{12}$ GeV to $10^{13}$ GeV.

  12. Gauge turbulence, topological defect dynamics, and condensation in Higgs models

    SciTech Connect (OSTI)

    Gasenzer, Thomas [Heidelberg Univ. (Germany). Inst. for Theoretische Physik; GSI-Darmstadt (Germany). ExtreMe Matter Inst. (EMMI); McLerran, Larry [Brookhaven National Lab. (BNL), Upton, NY (United States). RIKEN Research Center and Physics Dept.; China Central Normal Univ., Wuhan (China). Physics Dept.; Pawlowski, Jan M. [Heidelberg Univ. (Germany). Inst. for Theoretische Physik; GSI-Darmstadt (Germany). ExtreMe Matter Inst. (EMMI); Sexty, Dénes [Heidelberg Univ. (Germany). Inst. for Theoretische Physik; GSI-Darmstadt (Germany). ExtreMe Matter Inst. (EMMI)

    2014-10-01

    The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.

  13. Gauge turbulence, topological defect dynamics, and condensation in Higgs models

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

    Gasenzer, Thomas; McLerran, Larry; Pawlowski, Jan M.; Sexty, Dénes

    2014-07-28

    The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixedmore »point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.« less

  14. Defect Analysis of Vehicle Compressed Natural Gas

    E-Print Network [OSTI]

    Cylinder, translated and presented by J. P. Hsu, PhD, Smart Chemistry #12;Reason for Defect Analysis of CNG Composite Cylinder · Safety Issue - Four explosion accidents of auto used CNG composite material cylinders resulting huge personnel and vehicles loss. · Low Compliance Rate ­ Inspect 12119 Auto used CNG composite

  15. Premelting at Defects Within Bulk Colloidal Crystals

    E-Print Network [OSTI]

    Collings, Peter

    Premelting at Defects Within Bulk Colloidal Crystals A. M. Alsayed,1 M. F. Islam,1 J. Zhang,1 P. J at grain boundaries and dislocations within bulk colloidal crystals using real- time video microscopy. The crystals are equilibrium close-packed, three- dimensional colloidal structures made from thermally

  16. Defect-free ultrahigh flux asymmetric membranes

    DOE Patents [OSTI]

    Pinnau, Ingo (Austin, TX); Koros, William J. (Austin, TX)

    1990-01-01

    Defect-free, ultrahigh flux integrally-skinned asymmetric membranes having extremely thin surface layers (<0.2 .mu.m) comprised of glassy polymers are disclosed. The membranes are formed by casting an appropriate drope followed by forced convective evaporation of solvent to obtain a dry phase separated asymmetrical structure. The structure is then washed in a precipitation liquid and dried.

  17. Meningeal Defects alter the tangential migration of cortical interneurons in Foxc1hith/hith mice

    E-Print Network [OSTI]

    Zarbalis, Konstantinos; Choe, Youngshik; Siegenthaler, Julie A; Orosco, Lori A; Pleasure, Samuel J

    2012-01-01

    migration presents the primary mode of migration of corticalbe the primary cause for the observed migration defects.tangen- tial migration defects being a primary defect rather

  18. Mechanics of Notched Izod impact testing of polycarbonate

    E-Print Network [OSTI]

    Silberstein, Meredith N

    2005-01-01

    Polycarbonate is widely used as a transparent protective material because of its low density and excellent mechanical properties. However, when defects such as cracks or notches are introduced, it is subject to catastrophic ...

  19. Healing of defects in a two-dimensional granular crystal

    E-Print Network [OSTI]

    Rice, Marie C

    2014-01-01

    Using a macroscopic analog for a two dimensional hexagonal crystal, we perform an experimental investigation of the self-healing properties of circular grain defects with an emphasis on defect orientation. A circular grain ...

  20. Estimating the expected latency to failure due to manufacturing defects 

    E-Print Network [OSTI]

    Dorsey, David Michael

    2004-09-30

    Manufacturers of digital circuits test their products to find defective parts so they are not sold to customers. Despite extensive testing, some of their products that are defective pass the testing process. To combat ...

  1. Defect site prediction based upon statistical analysis of fault signatures 

    E-Print Network [OSTI]

    Trinka, Michael Robert

    2004-09-30

    Good failure analysis is the ability to determine the site of a circuit defect quickly and accurately. We propose a method for defect site prediction that is based on a site's probability of excitation, making no assumptions about the type...

  2. Sandia Energy - Research Challenge 4: Defect-Carrier Interactions

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

    technology challenges. research-challenge-4-defect-carrier-interactions-5001 Measured density of an InGaN quantum well (QW) deep-level defect located 0.15 eV above the valence...

  3. Linear elastic fracture mechanics in anisotropic solids : application to fluid-driven crack propagation

    E-Print Network [OSTI]

    Laubie, Hadrien Hyacinthe

    2013-01-01

    Fracture mechanics is a field of continuum mechanics with the objective to predict how cracks initiate and propagate in solids. It has a wide domain of application. While aerospace engineers want to make sure a defect in ...

  4. Research Article Neural Mechanisms Supporting Robust Discrimination

    E-Print Network [OSTI]

    Kilgard, Michael P.

    Research Article Neural Mechanisms Supporting Robust Discrimination of Spectrally and Temporally by spectrally and temporally degraded speech sounds will account for the robust behavioral discrimination of speech. We examined the behavioral discrimination of noise vocoded consonants and vowels by rats

  5. Evaluating Static Analysis Defect Warnings On Production Software

    E-Print Network [OSTI]

    Cortes, Corinna

    , software quality 1. Introduction Static analysis for software defect detection has become a popular topicEvaluating Static Analysis Defect Warnings On Production Software Nathaniel Ayewah, William Pugh,jpenix,zhou@google.com Abstract Static analysis tools for software defect detection are becoming widely used in practice. However

  6. Clustering Static Analysis Defect Reports to Reduce Maintenance Costs

    E-Print Network [OSTI]

    Weimer, Westley

    Clustering Static Analysis Defect Reports to Reduce Maintenance Costs Zachary P. Fry and Westley, for large systems, these tools often produce an overwhelming number of defect reports. Many of these defect reports are conceptually similar, but addressing each report separately costs developer effort

  7. Neuropsychological mechanisms of interval timing behavior

    E-Print Network [OSTI]

    Wilkinson, Gerald S.

    perceiving a beat in a musical composition to returning to the stove just prior to the tea kettle whistling to expecting a traffic light to change from red to green. Furthermore, interval timing is exhibited in a wide

  8. Structure and mechanical behavior of bird beaks

    E-Print Network [OSTI]

    Seki, Yasuaki

    2009-01-01

    The ray casting method . . . . . . . . . . . . . . . . . . .171 4.6.2.2 Ray Casting Method . . . . . . . . . . . .rendering generated by ray casting;(a) toucan foam with two

  9. Mechanical properties and tribological behavior of contaminate

    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 method inBook:Connect

  10. Scratch behavior of polymers 

    E-Print Network [OSTI]

    Lim, Goy Teck

    2005-11-01

    of DOCTOR OF PHILOSOPHY Approved by: Chair of Committee, J.N. Reddy Committee Members, H.-J. Sue A. Srinvas S. Suh Paul N. Roschke Head of Department, Dennis O?Neal August 2005 Major Subject: Mechanical Engineering iii ABSTRACT... Scratch Behavior of Polymers. (August 2005) Goy Teck Lim, B.Eng., National University of Singapore; M.Eng., National University of Singapore Chair of Advisory Committee: Dr. J.N. Reddy This dissertation work is focused on the analytical...

  11. Hyperrealism and subclassical behavior

    E-Print Network [OSTI]

    Karl Svozil

    2015-09-11

    For the classical mind, quantum mechanics is boggling enough; nevertheless more bizarre behavior could be imagined, thereby concentrating on propositional structures (empirical logics) that transcend the quantum domain. One can also consistently suppose predictions and probabilities which are neither classical nor quantum, but which are subject to subclassicality; that is, the additivity of probability for mutually exclusive, co-measurable observables, as formalized by admissibility rules and frame functions.

  12. Modeling defective part level due to static and dynamic defects based upon site observation and excitation balance 

    E-Print Network [OSTI]

    Dworak, Jennifer Lynn

    2004-09-30

    a subset that detects a high percentage of the defective parts and produces a low defective part level. Historically, test pattern generation has often been seen as a deterministic endeavor. Test sets are generated to deterministically ensure that a...

  13. A MULTIDIMENSIONAL AND MULTIPHYSICS APPROACH TO NUCLEAR FUEL BEHAVIOR SIMULATION

    SciTech Connect (OSTI)

    R. L. Williamson; J. D. Hales; S. R. Novascone; M. R. Tonks; D. R. Gaston; C. J. Permann; D. Andrs; R. C. Martineau

    2012-04-01

    Important aspects of fuel rod behavior, for example pellet-clad mechanical interaction (PCMI), fuel fracture, oxide formation, non-axisymmetric cooling, and response to fuel manufacturing defects, are inherently multidimensional in addition to being complicated multiphysics problems. Many current modeling tools are strictly 2D axisymmetric or even 1.5D. This paper outlines the capabilities of a new fuel modeling tool able to analyze either 2D axisymmetric or fully 3D models. These capabilities include temperature-dependent thermal conductivity of fuel; swelling and densification; fuel creep; pellet fracture; fission gas release; cladding creep; irradiation growth; and gap mechanics (contact and gap heat transfer). The need for multiphysics, multidimensional modeling is then demonstrated through a discussion of results for a set of example problems. The first, a 10-pellet rodlet, demonstrates the viability of the solution method employed. This example highlights the effect of our smeared cracking model and also shows the multidimensional nature of discrete fuel pellet modeling. The second example relies on our the multidimensional, multiphysics approach to analyze a missing pellet surface problem. As a final example, we show a lower-length-scale simulation coupled to a continuum-scale simulation.

  14. Transport on a Lattice with Dynamical Defects

    E-Print Network [OSTI]

    Francesco Turci; Andrea Parmeggiani; Estelle Pitard; M. Carmen Romano; Luca Ciandrini

    2013-01-10

    Many transport processes in nature take place on substrates, often considered as unidimensional lanes. These unidimensional substrates are typically non-static: affected by a fluctuating environment, they can undergo conformational changes. This is particularly true in biological cells, where the state of the substrate is often coupled to the active motion of macromolecular complexes, such as motor proteins on microtubules or ribosomes on mRNAs, causing new interesting phenomena. Inspired by biological processes such as protein synthesis by ribosomes and motor protein transport, we introduce the concept of localized dynamical sites coupled to a driven lattice gas dynamics. We investigate the phenomenology of transport in the presence of dynamical defects and find a novel regime characterized by an intermittent current and subject to severe finite-size effects. Our results demonstrate the impact of the regulatory role of the dynamical defects in transport, not only in biology but also in more general contexts.

  15. The ATLAS Data Quality Defect Database System

    E-Print Network [OSTI]

    T. Golling; H. S. Hayward; P. U. E. Onyisi; H. J. Stelzer; P. Waller

    2012-05-14

    The ATLAS experiment at the Large Hadron Collider has implemented a new system for recording information on detector status and data quality, and for transmitting this information to users performing physics analysis. This system revolves around the concept of "defects," which are well-defined, fine-grained, unambiguous occurrences affecting the quality of recorded data. The motivation, implementation, and operation of this system is described.

  16. Direct imaging of crystal structure and defects in metastable Ge{sub 2}Sb{sub 2}Te{sub 5} by quantitative aberration-corrected scanning transmission electron microscopy

    SciTech Connect (OSTI)

    Ross, Ulrich; Lotnyk, Andriy Thelander, Erik; Rauschenbach, Bernd

    2014-03-24

    Knowledge about the atomic structure and vacancy distribution in phase change materials is of foremost importance in order to understand the underlying mechanism of fast reversible phase transformation. In this Letter, by combining state-of-the-art aberration-corrected scanning transmission electron microscopy with image simulations, we are able to map the local atomic structure and composition of a textured metastable Ge{sub 2}Sb{sub 2}Te{sub 5} thin film deposited by pulsed laser deposition with excellent spatial resolution. The atomic-resolution scanning transmission electron microscopy investigations display the heterogeneous defect structure of the Ge{sub 2}Sb{sub 2}Te{sub 5} phase. The obtained results are discussed. Highly oriented Ge{sub 2}Sb{sub 2}Te{sub 5} thin films appear to be a promising approach for further atomic-resolution investigations of the phase change behavior of this material class.

  17. Dark matter from decaying topological defects

    SciTech Connect (OSTI)

    Hindmarsh, Mark [Helsinki Institute of Physics, Gustaf Hällströmin katu, P.O. Box 64, 00014 Helsinki University (Finland); Kirk, Russell; West, Stephen M., E-mail: m.b.hindmarsh@sussex.ac.uk, E-mail: russell.kirk.2008@live.rhul.ac.uk, E-mail: stephen.west@rhul.ac.uk [Dept. of Physics, Royal Holloway University of London, Egham Hill, Egham, Surrey, TW20 0EX (United Kingdom)

    2014-03-01

    We study dark matter production by decaying topological defects, in particular cosmic strings. In topological defect or ''top-down'' (TD) scenarios, the dark matter injection rate varies as a power law with time with exponent p?4. We find a formula in closed form for the yield for all p < 3/2, which accurately reproduces the solution of the Boltzmann equation. We investigate two scenarios (p = 1, p = 7/6) motivated by cosmic strings which decay into TeV-scale states with a high branching fraction into dark matter particles. For dark matter models annihilating either by s-wave or p-wave, we find the regions of parameter space where the TD model can account for the dark matter relic density as measured by Planck. We find that topological defects can be the principal source of dark matter, even when the standard freeze-out calculation under-predicts the relic density and hence can lead to potentially large ''boost factor'' enhancements in the dark matter annihilation rate. We examine dark matter model-independent limits on this scenario arising from unitarity and discuss example model-dependent limits coming from indirect dark matter search experiments. In the four cases studied, the upper bound on G? for strings with an appreciable channel into TeV-scale states is significantly more stringent than the current Cosmic Microwave Background limits.

  18. Sorting of Coffee Beans for 'Potato Defect' in East African Countries 

    E-Print Network [OSTI]

    Waikar, Shraddha Prakash

    2012-07-16

    of MASTER OF SCIENCE Approved by: Co-Chairs of Committee, Gholamreza Langari William Payne Committee Members, Gyula Vigh Arun Srinivasa Head of Department, Dennis O?neal MAY 2011 Major Subject: Mechanical Engineering iii ABSTRACT Sorting of Co ee... Beans for ?Potato Defect? in East African Countries. (May 2011) Shraddha Prakash Waikar, B.E., Vishwakarma Institute Of Technology Co{Chairs of Advisory Committee: Dr. Gholamreza Langari Dr. William Payne Since ancient times, co ee has been a savory...

  19. A single-molecule approach to ZnO defect studies: Single photons and single defects

    SciTech Connect (OSTI)

    Jungwirth, N. R.; Pai, Y. Y.; Chang, H. S.; MacQuarrie, E. R.; Nguyen, K. X.; Fuchs, G. D.

    2014-07-28

    Investigations that probe defects one at a time offer a unique opportunity to observe properties and dynamics that are washed out of ensemble measurements. Here, we present confocal fluorescence measurements of individual defects in ZnO nanoparticles and sputtered films that are excited with sub-bandgap energy light. Photon correlation measurements yield both antibunching and bunching, indicative of single-photon emission from isolated defects that possess a metastable shelving state. The single-photon emission is in the range of ?560–720?nm and typically exhibits two broad spectral peaks separated by ?150?meV. The excited state lifetimes range from 1 to 13?ns, consistent with the finite-size and surface effects of nanoparticles and small grains. We also observe discrete jumps in the fluorescence intensity between a bright state and a dark state. The dwell times in each state are exponentially distributed and the average dwell time in the bright (dark) state does (may) depend on the power of the exciting laser. Taken together, our measurements demonstrate the utility of a single-molecule approach to semiconductor defect studies and highlight ZnO as a potential host material for single-defect based applications.

  20. Transport by molecular motors in the presence of static defects

    E-Print Network [OSTI]

    Yan Chai; Reinhard Lipowsky; Stefan Klumpp

    2009-05-07

    The transport by molecular motors along cytoskeletal filaments is studied theoretically in the presence of static defects. The movements of single motors are described as biased random walks along the filament as well as binding to and unbinding from the filament. Three basic types of defects are distinguished, which differ from normal filament sites only in one of the motors' transition probabilities. Both stepping defects with a reduced probability for forward steps and unbinding defects with an increased probability for motor unbinding strongly reduce the velocities and the run lengths of the motors with increasing defect density. For transport by single motors, binding defects with a reduced probability for motor binding have a relatively small effect on the transport properties. For cargo transport by motors teams, binding defects also change the effective unbinding rate of the cargo particles and are expected to have a stronger effect.

  1. LANL: Mechanical testing and modeling in MST

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

    etc.). As the effects of processing are to critical to accurate prediction of its mechanical behavior, MST hosts a range of metallographic and characterization tools. Specific...

  2. The role of point defects and defect complexes in silicon device processing. Summary report and papers

    SciTech Connect (OSTI)

    Sopori, B.; Tan, T.Y.

    1994-08-01

    This report is a summary of a workshop hold on August 24--26, 1992. Session 1 of the conference discussed characteristics of various commercial photovoltaic silicon substrates, the nature of impurities and defects in them, and how they are related to the material growth. Session 2 on point defects reviewed the capabilities of theoretical approaches to determine equilibrium structure of defects in the silicon lattice arising from transitional metal impurities and hydrogen. Session 3 was devoted to a discussion of the surface photovoltaic method for characterizing bulk wafer lifetimes, and to detailed studies on the effectiveness of various gettering operations on reducing the deleterious effects of transition metals. Papers presented at the conference are also included in this summary report.

  3. Statistics of non-affine defect precursors: tailoring defect densities in colloidal crystals using external fields

    E-Print Network [OSTI]

    Saswati Ganguly; Surajit Sengupta; Peter Sollich

    2015-01-30

    Coarse-graining atomic displacements in a solid produces both local affine strains and "non-affine" fluctuations. Here we study the equilibrium dynamics of these coarse grained quantities to obtain space-time dependent correlation functions. We show how a subset of these thermally excited, non-affine fluctuations act as precursors for the nucleation of lattice defects and suggest how defect probabilities may be altered by an {\\it experimentally realisable} "external" field conjugate to the global non-affinity parameter. Our results are amenable to verification in experiments on colloidal crystals using commonly available holographic laser tweezer and video microscopy techniques, and may lead to simple ways of controlling the defect density of a colloidal solid.

  4. Evolution of microstructural defects with strain effects in germanium nanocrystals synthesized at different annealing temperatures

    SciTech Connect (OSTI)

    Zhang, Minghuan; Cai, Rongsheng; Zhang, Yujuan; Wang, Chao [The Cultivation Base for State Key Laboratory, Qingdao University, No. 308, Ningxia Road, Qingdao 266071 (China); College of Chemistry and Chemical Engineering, Qingdao University, No. 308, Ningxia Road, Qingdao 266071 (China); Wang, Yiqian, E-mail: yqwang@qdu.edu.cn [The Cultivation Base for State Key Laboratory, Qingdao University, No. 308, Ningxia Road, Qingdao 266071 (China); College of Physics Science, Qingdao University, No. 308, Ningxia Road, Qingdao 266071 (China); Ross, Guy G.; Barba, David [INRS-EMT, 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada)

    2014-07-01

    Ge nanocrystals (Ge-ncs) were produced by implantation of {sup 74}Ge{sup +} into a SiO{sub 2} film on (100) Si, followed by high-temperature annealing from 700 °C to 1100 °C. Transmission electron microscopy (TEM) studies show that the average size of Ge-ncs increases with the annealing temperature. High-resolution TEM (HRTEM) investigations reveal the presence of planar and linear defects in the formed Ge-ncs, whose relative concentrations are determined at each annealing temperature. The relative concentration of planar defects is almost independent of the annealing temperature up to 1000 °C. However, from 1000 °C to 1100 °C, its concentration decreases dramatically. For the linear defects, their concentration varies considerably with the annealing temperatures. In addition, by measuring the interplanar spacing of Ge-ncs from the HRTEM images, a strong correlation is found between the dislocation percentage and the stress field intensity. Our results provide fundamental insights regarding both the presence of microstructural defects and the origin of the residual stress field within Ge-ncs, which can shed light on the fabrication of Ge-ncs with quantified crystallinity and appropriate size for the advanced Ge-nc devices. - Highlights: • Growth of Ge nanocrystals at different annealing temperatures was investigated. • Strain field has great effects on the formation of dislocations. • Different mechanisms are proposed to explain growth regimes of Ge nanocrystals.

  5. Point defect distribution in high-mobility conductive SrTiO{sub 3} crystals

    SciTech Connect (OSTI)

    Gentils, A. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, CNRS-IN2P3-Universite Paris-Sud 11, 91405 Orsay Campus (France); CEMHTI Site Cyclotron, CNRS, 3A rue de la Ferollerie, 45071 Orleans Cedex 2 (France); Copie, O.; Bibes, M.; Bouzehouane, K.; Jacquet, E.; Carretero, C.; Barthelemy, A. [Unite Mixte de Physique CNRS/Thales associee a l'Universite Paris-Sud, Campus de Polytechnique, 1 Avenue A. Fresnel, 91767 Palaiseau (France); Herranz, G. [Unite Mixte de Physique CNRS/Thales associee a l'Universite Paris-Sud, Campus de Polytechnique, 1 Avenue A. Fresnel, 91767 Palaiseau (France); Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB, Bellaterra 08193, Catalonia (Spain); Fortuna, F. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, CNRS-IN2P3-Universite Paris-Sud 11, 91405 Orsay Campus (France); Basletic, M.; Tafra, E.; Hamzic, A. [Department of Physics, Faculty of Science, University of Zagreb, Bijenicka 32, P.O. Box 331, HR-10002 Zagreb (Croatia)

    2010-04-01

    We have carried out positron-annihilation spectroscopy to characterize the spatial distribution and the nature of vacancy defects in insulating as-received as well as in reduced SrTiO{sub 3} substrates exhibiting high-mobility conduction. The substrates were reduced either by ion etching the substrate surfaces or by doping with vacancies during thin-film deposition at low pressure and high temperature. We show that Ti vacancies are native defects homogeneously distributed in as-received substrates. In contrast, the dominant vacancy defects are the same both in ion etched crystals and substrates reduced during the film growth, and they consist of nonhomogeneous distributions of cation-oxygen vacancy complexes. Their spatial extension is tuned from a few microns in ion-etched samples to the whole substrate in specimens reduced during film deposition. Our results shed light on the transport mechanisms of conductive SrTiO{sub 3} crystals and on strategies for defect-engineered oxide quantum wells, wires, and dots.

  6. & 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

  7. Defects introduced into electroplated Cu films during room-temperature recrystallization probed by a monoenergetic positron beam

    SciTech Connect (OSTI)

    Uedono, A.; Suzuki, T.; Nakamura, T.; Ohdaira, T.; Suzuki, R. [Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Semiconductor Technology Academic Research Center, 17-2, Shin Yokohama 3-chome, Kohoku, Yokohama, Kanagawa 222-0033 (Japan); National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2005-08-15

    Positron annihilation was used to probe vacancy-type defects in electroplated Cu films deposited on Ta/SiO{sub 2}/Si. Doppler broadening spectra of the annihilation radiation were measured for the Cu films during grain growth at room temperature (i.e., self-annealing). The line-shape parameter S increased during self-annealing, and the observed time dependence of S was well described by the Johnson-Mehl-Avrami-Kolmogorov kinetics. After self-annealing, the values of S were found to be larger than the S value for annealed pure Cu, suggesting that the positrons annihilated from the trapped state by vacancy-type defects in grains. From a comparison with the results of previous isochronal annealing experiments, the major species of defects introduced during self-annealing was found to be vacancy clusters. The size of these defects increased, but their concentration decreased, with increasing film thickness. In thicker Cu films, an enhanced flow of atoms and subsequent rapid grain growth cause such defect behavior.

  8. Method of identifying defective particle coatings

    DOE Patents [OSTI]

    Cohen, Mark E. (San Diego, CA); Whiting, Carlton D. (San Diego, CA)

    1986-01-01

    A method for identifying coated particles having defective coatings desig to retain therewithin a build-up of gaseous materials including: (a) Pulling a vacuum on the particles; (b) Backfilling the particles at atmospheric pressure with a liquid capable of wetting the exterior surface of the coated particles, said liquid being a compound which includes an element having an atomic number higher than the highest atomic number of any element in the composition which forms the exterior surface of the particle coating; (c) Drying the particles; and (d) Radiographing the particles. By television monitoring, examination of the radiographs is substantially enhanced.

  9. Microstructure and Mechanical Properties of n-irradiated Fe-Cr Model Alloys

    SciTech Connect (OSTI)

    Matijasevic, Milena; Al Mazouzi, Abderrahim

    2008-07-01

    High chromium ( 9-12 wt %) ferritic/martensitic steels are candidate structural materials for future fusion reactors and other advanced systems such as accelerator driven systems (ADS). Their use for these applications requires a careful assessment of their mechanical stability under high energy neutron irradiation and in aggressive environments. In particular, the Cr concentration has been shown to be a key parameter to be optimized in order to guarantee the best corrosion and swelling resistance, together with the least embrittlement. In this work, the characterization of the neutron irradiated Fe-Cr model alloys with different Cr % with respect to microstructure and mechanical tests will be presented. The behavior of Fe-Cr alloys have been studied using tensile tests at different temperature range ( from -160 deg. C to 300 deg. C). Irradiation-induced microstructure changes have been studied by TEM for two different irradiation doses at 300 deg. C. The density and the size distribution of the defects induced have been determined. The tensile test results indicate that Cr content affects the hardening behavior of Fe-Cr binary alloys. Hardening mechanisms are discussed in terms of Orowan type of approach by correlating TEM data to the measured irradiation hardening. (authors)

  10. AUTOMATED DEFECT CLASSIFICATION USING AN ARTIFICIAL NEURAL NETWORK

    SciTech Connect (OSTI)

    Chady, T.; Caryk, M. [Szczecin University of Technology, Department of Electrical Engineering (Poland); Piekarczyk, B. [Technic-Control, Szczecin (Poland)

    2009-03-03

    The automated defect classification algorithm based on artificial neural network with multilayer backpropagation structure was utilized. The selected features of flaws were used as input data. In order to train the neural network it is necessary to prepare learning data which is representative database of defects. Database preparation requires the following steps: image acquisition and pre-processing, image enhancement, defect detection and feature extraction. The real digital radiographs of welded parts of a ship were used for this purpose.

  11. Improved, Defect-Free Electrode Materials - Energy Innovation...

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

    and Fuels Vehicles and Fuels Find More Like This Return to Search Improved, Defect-Free Electrode Materials Brookhaven National Laboratory Contact BNL About This Technology...

  12. Surface defect states in MBE-grown CdTe layers

    SciTech Connect (OSTI)

    Olender, Karolina; Wosinski, Tadeusz; Fronc, Krzysztof; Tkaczyk, Zbigniew; Chusnutdinow, Sergij; Karczewski, Grzegorz

    2014-02-21

    Semiconductor surface plays an important role in the technology of semiconductor devices. In the present work we report results of our deep-level transient spectroscopy (DLTS) investigations of surface defect states in nitrogen doped p-type CdTe layers grown by the molecular-beam epitaxy technique. We observed a deep-level trap associated with surface states, with the activation energy for hole emission of 0.33 eV. DLTS peak position in the spectra for this trap, and its ionization energy, strongly depend on the electric field. Our measurements allow to determine a mechanism responsible for the enhancement of hole emission rate from the traps as the phonon-assisted tunnel effect. Density of surface defect states significantly decreased as a result of passivation in ammonium sulfide. Capacitance-voltage measurements confirmed the results obtained by the DLTS technique.

  13. Density functional study of H-induced defects as nucleation sites in hybrid carbon nanomaterials.

    SciTech Connect (OSTI)

    Barnard, A.; Terranova, M. L.; Rossi, M.; Dip. Scienze e Tecnologie Chimiche; Dip di Energetica; INFM

    2005-01-01

    Recently we have reported on the growth of an exciting new class of hybrid nanostructured carbon materials, coupling nanosized diamond with single-walled carbon nanotubes. The inner structures were shown to be single-walled C nanotubes or bundles of single-walled nanotubes up to 15 {micro}m long, and the outer deposit consisted of faceted diamond crystallites with diameters in the range of 20-100 nm. To aid in understanding the mechanisms responsible for the formation of such materials, the present study uses density functional theory to examine the role of atomic hydrogen in creating localized sp{sup 3} hybridized defects on the outer wall of carbon nanotubes. The results illustrate that certain absorption configurations may produce defects containing dangling carbon bonds, and thus promote the formation of suitable sites for nanodiamond nucleation.

  14. 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

  15. 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.

  16. Mechanical and substructural response of incipiently spalled 316L stainless steel.

    SciTech Connect (OSTI)

    Gray, G. T. , III; Bourne, N. K.

    2004-01-01

    316L SS samples were shock prestrained to a peak stress of 6.6 GPa using a 0.75 {mu}sec pulse duration square-topped shock profile and 'soft' recovered while a second sample was similarly shock loaded, without spall momentum trapping, leading to incipient spall damage. Shock prestraining and 'soft' shock recovery to 6.6 GPa led to an increase in the post-shock flow strength of 316L SS by {approx}100 MPa over the starting material while the reload yield strength of the incipiently spall damaged sample increased by {approx}200 MPa. In this paper the sequential processes of defect generation and damage operative during the shock prestraining, spallation, and reloading of incipiently spalled 316L SS is presented. The influence of shock prestraining, using both triangular-wave loading, via both direct HE and triangular-wave pulses on a gas launcher, as well as 'square-topped' shock prestaining via conventional flyer-plate impact, is crucial to understanding the shock hardening and spallation responses of materials(Gray III, et al. [2003]). The development of predictive constitutive models to describe the mechanical response of incipiently damaged metals and alloys requires an understanding of the defect generation and storage due to shock hardening as well as the additional plasticity and damage evolution during spallation. In this paper the influence of shock-wave prestraining on the process of shock hardening and thereafterthe hardeningand damage evolution accompanying incipient spallation in 316L stainless steel (316L SS) on post-shock constitutive behavior is examined using 'soft' recovery techniques and mechanical behavior measurements.

  17. Understanding the Irradiation Behavior of Zirconium Carbide

    SciTech Connect (OSTI)

    Motta, Arthur; Sridharan, Kumar; Morgan, Dane; Szlufarska, Izabela

    2013-10-11

    Zirconium carbide (ZrC) is being considered for utilization in high-temperature gas-cooled reactor fuels in deep-burn TRISO fuel. Zirconium carbide possesses a cubic B1-type crystal structure with a high melting point, exceptional hardness, and good thermal and electrical conductivities. The use of ZrC as part of the TRISO fuel requires a thorough understanding of its irradiation response. However, the radiation effects on ZrC are still poorly understood. The majority of the existing research is focused on the radiation damage phenomena at higher temperatures (>450{degree}C) where many fundamental aspects of defect production and kinetics cannot be easily distinguished. Little is known about basic defect formation, clustering, and evolution of ZrC under irradiation, although some atomistic simulation and phenomenological studies have been performed. Such detailed information is needed to construct a model describing the microstructural evolution in fast-neutron irradiated materials that will be of great technological importance for the development of ZrC- based fuel. The goal of the proposed project is to gain fundamental understanding of the radiation-induced defect formation in zirconium carbide and irradiation response (ZrC) by using a combination of state-of-the-art experimental methods and atomistic modeling. This project will combine (1) in situ ion irradiation at a specialized facility at a national laboratory, (2) controlled temperature proton irradiation on bulk samples, and (3) atomistic modeling to gain a fundamental understanding of defect formation in ZrC. The proposed project will cover the irradiation temperatures from cryogenic temperature to as high as 800{degree}C, and dose ranges from 0.1 to 100 dpa. The examination of this wide range of temperatures and doses allows us to obtain an experimental data set that can be effectively used to exercise and benchmark the computer calculations of defect properties. Combining the examination of radiation-induced microstructures mapped spatially and temporally, microstructural evolution during post-irradiation annealing, and atomistic modeling of defect formation and transport energetics will provide new, critical understanding about property changes in ZrC. The behavior of materials under irradiation is determined by the balance between damage production, defect clustering, and lattice response. In order to predict those effects at high temperatures so targeted testing can be expanded and extrapolated beyond the known database, it is necessary to determine the defect energetics and mobilities as these control damage accumulation and annealing. In particular, low-temperature irradiations are invaluable for determining the regions of defect mobility. Computer simulation techniques are particularly useful for identifying basic defect properties, especially if closely coupled with a well-constructed and complete experimental database. The close coupling of calculation and experiment in this project will provide mutual benchmarking and allow us to glean a deeper understanding of the irradiation response of ZrC, which can then be applied to the prediction of its behavior in reactor conditions.

  18. Visualizing the Behavior of Polar Domains and Screening Charges...

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

    Visualizing the Behavior of Polar Domains and Screening Charges Under Electric and Mechanical Fields Event Sponsor: Mathematics and Computing Science - LANS Seminar Start Date: Sep...

  19. The impact of trench defects in InGaN/GaN light emitting diodes and implications for the “green gap” problem

    SciTech Connect (OSTI)

    Massabuau, F. C.-P., E-mail: fm350@cam.ac.uk; Oehler, F.; Pamenter, S. K.; Thrush, E. J.; Kappers, M. J.; Humphreys, C. J.; Oliver, R. A. [Department of Materials Science and Metallurgy, University of Cambridge, 22 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Davies, M. J.; Dawson, P. [Photon Science Institute, School of Physics and Astronomy, Alan Turing Building, University of Manchester, Manchester M13 9PL (United Kingdom); Kovács, A.; Dunin-Borkowski, R. E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt- Straße, D-52425 Jülich (Germany); Williams, T.; Etheridge, J. [Monash Centre for Electron Microscopy, Monash University, Clayton Campus, VIC 3800 (Australia); Hopkins, M. A.; Allsopp, D. W. E. [Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY (United Kingdom)

    2014-09-15

    The impact of trench defects in blue InGaN/GaN light emitting diodes (LEDs) has been investigated. Two mechanisms responsible for the structural degradation of the multiple quantum well (MQW) active region were identified. It was found that during the growth of the p-type GaN capping layer, loss of part of the active region enclosed within a trench defect occurred, affecting the top-most QWs in the MQW stack. Indium platelets and voids were also found to form preferentially at the bottom of the MQW stack. The presence of high densities of trench defects in the LEDs was found to relate to a significant reduction in photoluminescence and electroluminescence emission efficiency, for a range of excitation power densities and drive currents. This reduction in emission efficiency was attributed to an increase in the density of non-radiative recombination centres within the MQW stack, believed to be associated with the stacking mismatch boundaries which form part of the sub-surface structure of the trench defects. Investigation of the surface of green-emitting QW structures found a two decade increase in the density of trench defects, compared to its blue-emitting counterpart, suggesting that the efficiency of green-emitting LEDs may be strongly affected by the presence of these defects. Our results are therefore consistent with a model that the “green gap” problem might relate to localized strain relaxation occurring through defects.

  20. IEEE TRANSACTIONS ON MAGNETICS, VOL. 40, NO. 1, JANUARY 2004 43 Mechanical Damage Detection With Magnetic

    E-Print Network [OSTI]

    Clapham, Lynann

    pipe wall. In addition to corrosion defects, dents or "mechanical damage" in pipelines are also, stress. I. INTRODUCTION NONDESTRUCTIVE evaluation of in-service oil and gas pipelines by the magnetic to study MFL signals from corrosion pits [3]­[7]. Because these defects produce MFL signals mainly due

  1. Oxide Film and Porosity Defects in Magnesium Alloy AZ91

    SciTech Connect (OSTI)

    Wang, Liang [Mississippi State University (MSU); Rhee, Hongjoo [Mississippi State University (MSU); Felicelli, Sergio D. [Mississippi State University (MSU); Sabau, Adrian S [ORNL; Berry, John T. [Mississippi State University (MSU)

    2009-01-01

    Porosity is a major concern in the production of light metal parts. This work aims to identify some of the mechanisms of microporosity formation in magnesium alloy AZ91. Microstructure analysis was performed on several samples obtained from gravity-poured ingots in graphite plate molds. Temperature data during cooling was acquired with type K thermocouples at 60 Hz at three locations of each casting. The microstructure of samples extracted from the regions of measured temperature was then characterized with optical metallography. Tensile tests and conventional four point bend tests were also conducted on specimens cut from the cast plates. Scanning electron microscopy was then used to observe the microstructure on the fracture surface of the specimens. The results of this study revealed the existence of abundant oxide film defects, similar to those observed in aluminum alloys. Remnants of oxide films were detected on some pore surfaces, and folded oxides were observed in fracture surfaces indicating the presence of double oxides entrained during pouring.

  2. Asymptotic Expansions of Defective Renewal Equations with Applications to Perturbed

    E-Print Network [OSTI]

    Blanchet, Jose H.

    Asymptotic Expansions of Defective Renewal Equations with Applications to Perturbed Risk Models. These expansions are applied to the analysis of Processor Sharing queues and perturbed risk models, and yield Introduction A defective renewal equation for a function ap (·) takes the form ap (t) = bp (t) + (1 - p) [0,t

  3. Fluctuations from edge defects in superconducting resonators A. Megrant,1

    E-Print Network [OSTI]

    Martinis, John M.

    Fluctuations from edge defects in superconducting resonators C. Neill,1 A. Megrant,1 R. Barends,1 August 2013) Superconducting resonators, used in astronomy and quantum computation, couple strongly to microscopic two-level defects. We monitor the microwave response of superconducting resonators and observe

  4. Simple intrinsic defects in InAs : numerical predictions.

    SciTech Connect (OSTI)

    Schultz, Peter Andrew

    2013-03-01

    This Report presents numerical tables summarizing properties of intrinsic defects in indium arsenide, InAs, as computed by density functional theory using semi-local density functionals, intended for use as reference tables for a defect physics package in device models.

  5. Inflaton fluctuations in the presence of cosmological defects

    E-Print Network [OSTI]

    Hing-Tong Cho; Kin-Wang Ng; I-Chin Wang

    2014-10-06

    We study quantum fluctuations of a free massless scalar field during inflation in the presence of a point, line, or plane defect such as a black hole, cosmic string, or domain wall, using a perturbative expansion in powers of small defect parameters. We provide results for the scalar two-point correlation functions that show explicitly a small violation of translational invariance during inflation.

  6. Exploring the factors associated with preconception health behaviors among women of childbearing age: a naturalistic inquiry 

    E-Print Network [OSTI]

    Delissaint, Dieula

    2009-05-15

    deformities and cognitive deficits (Coles, 1994; CDC, 2005b). Insufficient intake of folic acid before pregnancy contributes to neural tube defects (Yang et al., 2007). These types of behaviors are preventable, are open to intervention, and if ameliorated... preconception care as it relates to intended pregnancy. Studies testing women?s knowledge of preconception health focus mainly on the knowledge of intake of folic acid supplements to reduce neural tube defects (Frey & Files, 2006; Perlow, 2001; Quillin et al...

  7. Spin from defects in two-dimensional quantum field theory

    E-Print Network [OSTI]

    Sebastian Novak; Ingo Runkel

    2015-06-24

    We build two-dimensional quantum field theories on spin surfaces starting from theories on oriented surfaces with networks of topological defect lines and junctions. The construction uses a combinatorial description of the spin structure in terms of a triangulation equipped with extra data. The amplitude for the spin surfaces is defined to be the amplitude for the underlying oriented surface together with a defect network dual to the triangulation. Independence of the triangulation and of the other choices follows if the line defect and junctions are obtained from a Delta-separable Frobenius algebra with involutive Nakayama automorphism in the monoidal category of topological defects. For rational conformal field theory we can give a more explicit description of the defect category, and we work out two examples related to free fermions in detail: the Ising model and the so(n) WZW model at level 1.

  8. Spin from defects in two-dimensional quantum field theory

    E-Print Network [OSTI]

    Novak, Sebastian

    2015-01-01

    We build two-dimensional quantum field theories on spin surfaces starting from theories on oriented surfaces with networks of topological defect lines and junctions. The construction uses a combinatorial description of the spin structure in terms of a triangulation equipped with extra data. The amplitude for the spin surfaces is defined to be the amplitude for the underlying oriented surface together with a defect network dual to the triangulation. Independence of the triangulation and of the other choices follows if the line defect and junctions are obtained from a Delta-separable Frobenius algebra with involutive Nakayama automorphism in the monoidal category of topological defects. For rational conformal field theory we can give a more explicit description of the defect category, and we work out two examples related to free fermions in detail: the Ising model and the so(n) WZW model at level 1.

  9. Eddy Current Testing for Detecting Small Defects in Thin Films

    SciTech Connect (OSTI)

    Obeid, Simon; Tranjan, Farid M. [Electrical and Computer Engineering Department, UNCC (United States); Dogaru, Teodor [Albany Instruments, 426-O Barton Creek, Charlotte, NC 28262 (United States)

    2007-03-21

    Presented here is a technique of using Eddy Current based Giant Magneto-Resistance sensor (GMR) to detect surface and sub-layered minute defects in thin films. For surface crack detection, a measurement was performed on a copper metallization of 5-10 microns thick. It was done by scanning the GMR sensor on the surface of the wafer that had two scratches of 0.2 mm, and 2.5 mm in length respectively. In another experiment, metal coatings were deposited over the layers containing five defects with known lengths such that the defects were invisible from the surface. The limit of detection (resolution), in terms of defect size, of the GMR high-resolution Eddy Current probe was studied using this sample. Applications of Eddy Current testing include detecting defects in thin film metallic layers, and quality control of metallization layers on silicon wafers for integrated circuits manufacturing.

  10. Nonlinear beam deflection in photonic lattices with negative defects

    SciTech Connect (OSTI)

    Wang Jiandong [College of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Ye Zhuoyi; Lou Cibo [TEDA Applied Physical School, Nankai University, Tianjin 300457 (China); Miller, Alexandra; Zhang Peng [Department of Physics and Astronomy, San Francisco State University, San Francisco, California 94132 (United States); Hu Yi; Chen Zhigang [TEDA Applied Physical School, Nankai University, Tianjin 300457 (China); Department of Physics and Astronomy, San Francisco State University, San Francisco, California 94132 (United States); Yang Jianke [Department of Mathematics and Statistics, University of Vermont, Burlington, Vermont 05401 (United States)

    2011-03-15

    We demonstrate both theoretically and experimentally that a nonlinear beam can be reflected by a negative defect in a photonic lattice if the incident angle is below a threshold value. Above this threshold angle, the beam simply passes through the defect. This phenomenon occurs in both one- and two-dimensional photonic lattices, and it provides a way to use the incident angle to control beam propagation in a lattice network. If the defect is absent or positive, no evident transition from reflection to transmission occurs. These nonlinear phenomena are also compared with linear nondiffracting-beam propagation in a photonic lattice with a defect, and both similarities and differences are observed. In addition, some important features in linear and nonlinear beam propagations are explained analytically by using a linear model with a delta-function defect.

  11. Operating Experience Level 3: Radcalc V4.1 Software Defect |...

    Office of Environmental Management (EM)

    Operating Experience Level 3: Radcalc V4.1 Software Defect Operating Experience Level 3: Radcalc V4.1 Software Defect September 6, 2011 OE-3 2011-01: Radcalc V4.1 Software Defect...

  12. 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

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

    E-Print Network [OSTI]

    Sun, Cheng

    2013-04-26

    loops. Here we provide experimental evidence that high angle grain boundaries can effectively remove radiation-induced defects. The equal channel angular pressing (ECAP) technique was used to produce ultrafine grained Fe-Cr-Ni alloy. Mechanical...

  14. THE NA,K-ATPASE ?4 ISOFORM: MECHANISMS OF ACTION, REGULATION AND RELEVANCE TO MALE FERTILITY

    E-Print Network [OSTI]

    Jimenez Alarcon, Tamara

    2011-08-31

    Ion movement across the plasma membrane is essential for the function of spermatozoa and defects in the mechanisms that drive ion transport between the environment and cell cytoplasm can affect male fertility. The active ...

  15. On the dynamic behavior of mineralized tissues

    E-Print Network [OSTI]

    Kulin, Robb Michael

    2010-01-01

    Static and Dynamic Loading. Engineering Fracture Mechanics,static fracture behavior (mode I, mode II and mode III fracture tests), including experiments on the fracture mechanicsstatic and dynamic fracture. 4.2.2 Introduction Improving our understanding of the fracture mechanics

  16. Modeling and experimental characterization of stepped and v-shaped (311) defects in silicon

    SciTech Connect (OSTI)

    Marqués, Luis A. Aboy, María; Dudeck, Karleen J.; Botton, Gianluigi A.; Knights, Andrew P.; Gwilliam, Russell M.

    2014-04-14

    We propose an atomistic model to describe extended (311) defects in silicon. It is based on the combination of interstitial and bond defect chains. The model is able to accurately reproduce not only planar (311) defects but also defect structures that show steps, bends, or both. We use molecular dynamics techniques to show that these interstitial and bond defect chains spontaneously transform into extended (311) defects. Simulations are validated by comparing with precise experimental measurements on actual (311) defects. The excellent agreement between the simulated and experimentally derived structures, regarding individual atomic positions and shape of the distinct structural (311) defect units, provides strong evidence for the robustness of the proposed model.

  17. Accounting for Localized Defects in the Optoelectronic Design of Thin-Film Solar Cells

    E-Print Network [OSTI]

    Deceglie, Michael G.

    2014-01-01

    Accounting for Localized Defects in the OptoelectronicH solar cells. Explicitly accounting for local variations inthe importance of accounting for defect geometry, and that

  18. Probing graphene defects and estimating graphene quality with optical microscopy

    SciTech Connect (OSTI)

    Lai, Shen [SKKU Advanced Institute of Nanotechnology (SAINT), Suwon 440-746 (Korea, Republic of); Center for Human Interface Nanotechnology (HINT), Suwon 440-746 (Korea, Republic of); Kyu Jang, Sung [SKKU Advanced Institute of Nanotechnology (SAINT), Suwon 440-746 (Korea, Republic of); Jae Song, Young, E-mail: yjsong@skku.edu [SKKU Advanced Institute of Nanotechnology (SAINT), Suwon 440-746 (Korea, Republic of); Department of Physics, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of); Lee, Sungjoo, E-mail: leesj@skku.edu [SKKU Advanced Institute of Nanotechnology (SAINT), Suwon 440-746 (Korea, Republic of); Center for Human Interface Nanotechnology (HINT), Suwon 440-746 (Korea, Republic of); College of Information and Communication Engineering, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of)

    2014-01-27

    We report a simple and accurate method for detecting graphene defects that utilizes the mild, dry annealing of graphene/Cu films in air. In contrast to previously reported techniques, our simple approach with optical microscopy can determine the density and degree of dislocation of defects in a graphene film without inducing water-related damage or functionalization. Scanning electron microscopy, confocal Raman and atomic force microscopy, and X-ray photoelectron spectroscopy analysis were performed to demonstrate that our nondestructive approach to characterizing graphene defects with optimized thermal annealing provides rapid and comprehensive determinations of graphene quality.

  19. Mechanical Properties of Lithium-Ion Battery Separator Materials

    E-Print Network [OSTI]

    Petta, Jason

    Mechanical Properties of Lithium-Ion Battery Separator Materials Patrick Sinko B.S. Materials and motivation ­ Why study lithium-ion batteries? ­ Lithium-ion battery fundamentals ­ Why study the mechanical behaviors in lithium-ion batteries? · Current work ­ Mechanical behaviors the separator ­ How do we test

  20. Heavy and Overweight Vehicle Defects Interim Report

    SciTech Connect (OSTI)

    Siekmann, Adam [ORNL; Capps, Gary J [ORNL

    2012-12-01

    The Federal Highway Administration (FHWA), along with the Federal Motor Carrier Safety Administration (FMCSA), has an interest in overweight commercial motor vehicles, how they affect infrastructure, and their impact on safety on the nation s highways. To assist both FHWA and FMCSA in obtaining more information related to this interest, data was collected and analyzed from two separate sources. A large scale nationwide data collection effort was facilitated by the Commercial Vehicle Safety Alliance as part of a special study on overweight vehicles and an additional, smaller set, of data was collected from the state of Tennessee which included a much more detailed set of data. Over a six-month period, 1,873 Level I inspections were performed in 18 different states that volunteered to be a part of this study. Of the 1,873 inspections, a vehicle out-of-service (OOS) violation was found on 44.79% of the vehicles, a rate significantly higher than the national OOS rate of 27.23%. The main cause of a vehicle being placed OOS was brake-related defects, with approximately 30% of all vehicles having an OOS brake violation. Only about 4% of vehicles had an OOS tire violation, and even fewer had suspension and wheel violations. Vehicle weight violations were most common on an axle group as opposed to a gross vehicle weight violation. About two thirds of the vehicles cited with a weight violation were overweight on an axle group with an average amount of weight over the legal limit of about 2,000 lbs. Data collection is scheduled to continue through January 2014, with more potentially more states volunteering to collect data. More detailed data collections similar to the Tennessee data collection will also be performed in multiple states.

  1. Defect reaction network in Si-doped InP : numerical predictions.

    SciTech Connect (OSTI)

    Schultz, Peter Andrew

    2013-10-01

    This Report characterizes the defects in the defect reaction network in silicon-doped, n-type InP deduced from first principles density functional theory. The reaction network is deduced by following exothermic defect reactions starting with the initially mobile interstitial defects reacting with common displacement damage defects in Si-doped InP until culminating in immobile reaction products. The defect reactions and reaction energies are tabulated, along with the properties of all the silicon-related defects in the reaction network. This Report serves to extend the results for intrinsic defects in SAND 2012-3313: %E2%80%9CSimple intrinsic defects in InP: Numerical predictions%E2%80%9D to include Si-containing simple defects likely to be present in a radiation-induced defect reaction sequence.

  2. Electron Beam Guides Engineering of Functional Defects | ornl...

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

    Materials Characterization Electron Beam Guides Engineering of Functional Defects May 20, 2015 Shown is a Z-contrast image of a vacancy-induced inversion domain (highlighted by the...

  3. 2005 May JOM 29 Casting DefectsOverview

    E-Print Network [OSTI]

    Beckermann, Christoph

    2005 May · JOM 29 Casting DefectsOverview Casting designs are generally based factors of safety, which leadtoincreasedcomponentweightsand inefficient use of materials. In castings in castings and determine their effect on performance. INTRODUCTION Designers are responsible for the per

  4. Re-entrant Lithium Local Environments and Defect Driven Electrochemist...

    Office of Scientific and Technical Information (OSTI)

    Lithium Local Environments and Defect Driven Electrochemistry of Li- and Mn-Rich Li-Ion Battery Cathodes Citation Details In-Document Search This content will become publicly...

  5. Defect specific maintenance of SG tubes -- How safe is it?

    SciTech Connect (OSTI)

    Cizelj, L.; Mavko, B.; Dvorsek, T. [Jozef Stefan Institute, Ljubljana (Slovenia)

    1997-02-01

    The efficiency of the defect specific plugging criterion for outside diameter stress corrosion cracking at tube support plates is assessed. The efficiency is defined by three parameters: (1) number of plugged tubes, (2) probability of steam generator tube rupture and (3) predicted accidental leak rate through the defects. A probabilistic model is proposed to quantify the probability of tube rupture, while procedures available in literature were used to define the accidental leak rates. The defect specific plugging criterion was then compared to the performance of traditional (45%) plugging criterion using realistic data from Krsko nuclear power plant. Advantages of the defect specific approach over the traditional one are clearly shown. Some hints on the optimization of safe life of steam generator are also given.

  6. Multiscale Defect Formation and Transport in Materials in Extreme Environments

    E-Print Network [OSTI]

    Seif, Dariush

    2013-01-01

    material symmetry (Iso, Anis) in the defect dipole tensors (through the [110]: Iso. P , Iso. ? (a) [110]: Anis. P ,Iso. ? [110]: Anis. P (1) , Anis. ? [100]: Iso. P , Iso. ? (

  7. Built-In Self Test (BIST) for Realistic Delay Defects 

    E-Print Network [OSTI]

    Tamilarasan, Karthik Prabhu

    2012-02-14

    Testing of delay defects is necessary in deep submicron (DSM) technologies. High coverage delay tests produced by automatic test pattern generation (ATPG) can be applied during wafer and package tests, but are difficult ...

  8. New Composite Silicon-Defect Graphene Anode Architecture

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

    A New Composite Silicon-Defect Graphene Anode Architecture for High Capacity, High-Rate Li-ion Batteries Xin Zhao, Cary Hayner, Mayfair Kung, and Harold Kung, Northwestern...

  9. Method and apparatus for inspecting reflection masks for defects

    DOE Patents [OSTI]

    Bokor, Jeffrey (Oakland, CA); Lin, Yun (Berkeley, CA)

    2003-04-29

    An at-wavelength system for extreme ultraviolet lithography mask blank defect detection is provided. When a focused beam of wavelength 13 nm is incident on a defective region of a mask blank, three possible phenomena can occur. The defect will induce an intensity reduction in the specularly reflected beam, scatter incoming photons into an off-specular direction, and change the amplitude and phase of the electric field at the surface which can be monitored through the change in the photoemission current. The magnitude of these changes will depend on the incident beam size, and the nature, extent and size of the defect. Inspection of the mask blank is performed by scanning the mask blank with 13 nm light focused to a spot a few .mu.m in diameter, while measuring the reflected beam intensity (bright field detection), the scattered beam intensity (dark-field detection) and/or the change in the photoemission current.

  10. Temperature Anisotropies in a Universe with Global Defects

    E-Print Network [OSTI]

    David Coulson

    1994-07-15

    We present a technique of calculating microwave anisotropies from global defects in a reionised universe. We concentrate on angular scales down to one degree where we expect the nongaussianity of the temperature anisotropy in these models to become apparent.

  11. Atomic Scale Details of Defect-Boundary Interactions 

    E-Print Network [OSTI]

    Chen, Di

    2014-12-18

    The study is aimed to understand atomic scale details of defect-boundary interactions, which are critical to develop radiation tolerant fuel cladding materials for harsher neutron environments. By means of molecular dynamics simulations, we...

  12. Design and optimization of a defect tolerant processor array 

    E-Print Network [OSTI]

    Lakkapragada, Bhavani S

    1995-01-01

    In this thesis we design and optimization of a defect tolerant MIMD processor array, for maximum performance per wafer area, targeted at applications that have a large number of operations per memory word, is described. The optimization includes...

  13. Mitigation of substrate defects in reticles using multilayer buffer layers

    DOE Patents [OSTI]

    Mirkarimi, Paul B. (Sunol, CA); Bajt, Sasa (Livermore, CA); Stearns, Daniel G. (Los Altos, CA)

    2001-01-01

    A multilayer film is used as a buffer layer to minimize the size of defects on a reticle substrate prior to deposition of a reflective coating on the substrate. The multilayer buffer layer deposited intermediate the reticle substrate and the reflective coating produces a smoothing of small particles and other defects on the reticle substrate. The reduction in defect size is controlled by surface relaxation during the buffer layer growth process and by the degree of intermixing and volume contraction of the materials at the multilayer interfaces. The buffer layers are deposited at near-normal incidence via a low particulate ion beam sputtering process. The growth surface of the buffer layer may also be heated by a secondary ion source to increase the degree of intermixing and improve the mitigation of defects.

  14. Introduction! Sickness behavior is defined as an organized suite of behavioral

    E-Print Network [OSTI]

    Muehlenbein, Michael

    that occurs during infection in both humans and non- human animals (Hart 1988). These behavioral changes include lethargy, decreased food intake/anorexia, decreased water intake, anhedonia, decreased exploration; Adelman and Martin 2009). Sickness behavior is thought to be a mechanism redistributing energy towards

  15. Luminescence properties of defects in GaN

    SciTech Connect (OSTI)

    Reshchikov, Michael A.; Morkoc, Hadis [Department of Electrical Engineering and Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)

    2005-03-15

    Gallium nitride (GaN) and its allied binaries InN and AIN as well as their ternary compounds have gained an unprecedented attention due to their wide-ranging applications encompassing green, blue, violet, and ultraviolet (UV) emitters and detectors (in photon ranges inaccessible by other semiconductors) and high-power amplifiers. However, even the best of the three binaries, GaN, contains many structural and point defects caused to a large extent by lattice and stacking mismatch with substrates. These defects notably affect the electrical and optical properties of the host material and can seriously degrade the performance and reliability of devices made based on these nitride semiconductors. Even though GaN broke the long-standing paradigm that high density of dislocations precludes acceptable device performance, point defects have taken the center stage as they exacerbate efforts to increase the efficiency of emitters, increase laser operation lifetime, and lead to anomalies in electronic devices. The point defects include native isolated defects (vacancies, interstitial, and antisites), intentional or unintentional impurities, as well as complexes involving different combinations of the isolated defects. Further improvements in device performance and longevity hinge on an in-depth understanding of point defects and their reduction. In this review a comprehensive and critical analysis of point defects in GaN, particularly their manifestation in luminescence, is presented. In addition to a comprehensive analysis of native point defects, the signatures of intentionally and unintentionally introduced impurities are addressed. The review discusses in detail the characteristics and the origin of the major luminescence bands including the ultraviolet, blue, green, yellow, and red bands in undoped GaN. The effects of important group-II impurities, such as Zn and Mg on the photoluminescence of GaN, are treated in detail. Similarly, but to a lesser extent, the effects of other impurities, such as C, Si, H, O, Be, Mn, Cd, etc., on the luminescence properties of GaN are also reviewed. Further, atypical luminescence lines which are tentatively attributed to the surface and structural defects are discussed. The effect of surfaces and surface preparation, particularly wet and dry etching, exposure to UV light in vacuum or controlled gas ambient, annealing, and ion implantation on the characteristics of the defect-related emissions is described.

  16. Rapid Coarsening of Ion Beam Ripple Patterns by Defect Annihilation

    SciTech Connect (OSTI)

    Hansen, Henri; Messlinger, Sebastian; Stoian, Georgiana [I. Physikalisches Institut, RWTH Aachen, 52056 Aachen (Germany); Redinger, Alex [I. Physikalisches Institut, RWTH Aachen, 52056 Aachen (Germany); II. Physikalisches Institut, Universitaet zu Koeln, 50937 Koeln, Zuelpicher Strasse 77 (Germany); Krug, Joachim [Institut fuer Theoretische Physik, Universitaet zu Koeln, 50937 Koeln, Zuelpicher Strasse 77 (Germany); Michely, Thomas [II. Physikalisches Institut, Universitaet zu Koeln, 50937 Koeln, Zuelpicher Strasse 77 (Germany)

    2009-04-10

    Ripple patterns formed on Pt(111) through grazing incidence ion beam erosion coarsen rapidly. At and below 450 K coarsening of the patterns is athermal and kinetic, unrelated to diffusion and surface free energy. Similar to the situation for sand dunes, coarsening takes place through annihilation reactions of mobile defects in the pattern. The defect velocity derived on the basis of a simple model agrees quantitatively with the velocity of monatomic steps illuminated by the ion beam.

  17. Ultrasonic Tomography for Detecting and Locating Defects in Concrete Structures 

    E-Print Network [OSTI]

    White, Joshua

    2012-07-16

    ....................................................... 18 Figure 6 Typical C-scans for simulated defects in shotcrete slabs: Specimens D, E, I, and M ............................................................................................... 19 Figure 7 Clay lump slab construction... and shotcrete s labs. Figs. 5 and 6 delaminations, are shown in Figs. 5 and 6. The images in these figures are representative 19 19 Fig. 6. Typical C-scans for simulated defects in shotcrete slabs: Specimens D (top left), E (top right), I (bottom...

  18. Graphene materials having randomly distributed two-dimensional structural defects

    DOE Patents [OSTI]

    2013-10-08

    Graphene-based storage materials for high-power battery applications are provided. The storage materials are composed of vertical stacks of graphene sheets and have reduced resistance for Li ion transport. This reduced resistance is achieved by incorporating a random distribution of structural defects into the stacked graphene sheets, whereby the structural defects facilitate the diffusion of Li ions into the interior of the storage materials.

  19. Crystal defect studies using x-ray diffuse scattering

    SciTech Connect (OSTI)

    Larson, B.C.

    1980-01-01

    Microscopic lattice defects such as point (single atom) defects, dislocation loops, and solute precipitates are characterized by local electronic density changes at the defect sites and by distortions of the lattice structure surrounding the defects. The effect of these interruptions of the crystal lattice on the scattering of x-rays is considered in this paper, and examples are presented of the use of the diffuse scattering to study the defects. X-ray studies of self-interstitials in electron irradiated aluminum and copper are discussed in terms of the identification of the interstitial configuration. Methods for detecting the onset of point defect aggregation into dislocation loops are considered and new techniques for the determination of separate size distributions for vacancy loops and interstitial loops are presented. Direct comparisons of dislocation loop measurements by x-rays with existing electron microscopy studies of dislocation loops indicate agreement for larger size loops, but x-ray measurements report higher concentrations in the smaller loop range. Methods for distinguishing between loops and three-dimensional precipitates are discussed and possibilities for detailed studies considered. A comparison of dislocation loop size distributions obtained from integral diffuse scattering measurements with those from TEM show a discrepancy in the smaller sizes similar to that described above.

  20. Magnesium behavior and structural defects in Mg+ ion implanted silicon carbide

    SciTech Connect (OSTI)

    Jiang, Weilin; Jung, Hee Joon; Kovarik, Libor; Wang, Zhaoying; Roosendaal, Timothy J.; Zhu, Zihua; Edwards, Danny J.; Hu, Shenyang Y.; Henager, Charles H.; Kurtz, Richard J.; Wang, Yongqiang

    2015-01-01

    As a candidate material for fusion reactor applications, silicon carbide (SiC) undergoes transmutation reactions under high-energy neutron irradiation with magnesium as the major metallic transmutant; the others include aluminum, beryllium and phosphorus in addition to helium and hydrogen gaseous species. The impact of these transmutants on SiC structural stability is currently unknown. This study uses ion implantation to introduce Mg into SiC. Multiaxial ion-channeling analysis of the as-produced damage state suggests that there are preferred Si <100> interstitial splits. The microstructure of the annealed sample was examined using high-resolution scanning transmission electron microscopy. The results show a high concentration of likely non-faulted tetrahedral voids and possible stacking fault tetrahedra near the damage peak. In addition to lattice distortion, dislocations and intrinsic and extrinsic stacking faults are also observed. Magnesium in 3C-SiC prefers to substitute for Si and it forms precipitates of cubic Mg2Si and tetragonal MgC2. The diffusion coefficient of Mg in 3C-SiC single crystal at 1573 K has been determined to be 3.8±0.4×10e-19 m2/sec.

  1. Transition Metal Defect Behavior and Si Density of States in the Processing Temperature Regime

    E-Print Network [OSTI]

    Dunham, Scott

    density of states as a function of temperature and generate a third density of states model based on 0 K deleterious effects on performance, yield and reliability. In silicon photovoltaics, we are concerned

  2. Implications of Permeation through Intrinsic Defects in Graphene on the Design of Defect-Tolerant Membranes for Gas Separation

    E-Print Network [OSTI]

    Sun, Chengzhen

    Gas transport through intrinsic defects and tears is a critical yet poorly understood phenomenon in graphene membranes for gas separation. We report that independent stacking of graphene layers on a porous support exponentially ...

  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. Defect studies in low-temperature-grown GaAs

    SciTech Connect (OSTI)

    Bliss, D.E.

    1992-11-01

    High content of excess As is incorporated in GaAs grown by low-temperature molecular-beam-epitaxy (LTMBE). The excess As exists primarily as As antisite defects AsGa and a lesser extent of gallium vacancies V[sub Ga]. The neutral AsGa-related defects were measured by infrared absorption at 1[mu]m. Gallium vacancies, V[sub Ga], was investigated by slow positron annihilation. Dependence of defect contents on doping was studied by Si and Be dopants. No free carriers are generated by n-type or p-type doping up to 10[sup 19] cm[sup [minus]3] Si or Be. Raman data indicate Be occupies Ga substitutional sites but Si atom is not substitutional. Si induces more As[sub Ga] in the layer. As As[sub Ga] increases, photoquenchable As[sub Ga] decreases. Fraction of photoquenchable defects correlates to defects within 3 nearest neighbor separations disrupting the metastability. Annealing reduces neutral As[sub Ga] content around 500C, similar to irradiation damaged and plastically deformed Ga[sub As], as opposed to bulk grown GaAs in which As[sub Ga]-related defects are stable up to 1100C. The lower temperature defect removal is due to V[sub Ga] enhanced diffusion of As[sub Ga] to As precipitates. The supersaturated V[sub GA] and also decreases during annealing. Annealing kinetics for As[sub Ga]-related defects gives 2.0 [plus minus] 0.3 eV and 1.5 [plus minus] 0.3 eV migration enthalpies for the As[sub Ga] and V[sub Ga]. This represents the difference between Ga and As atoms hopping into the vacancy. The non-photoquenchable As[sub Ga]-related defects anneal with an activation energy of 1.1 [plus minus] 0.3eV. Be acceptors can be activated by 800C annealing. Temperature difference between defect annealing and Be activation formation of As[sub Ga]-Be[sub Ga] pairs. Si donors can only be partially activated.

  5. Context-based automated defect classification system using multiple morphological masks

    DOE Patents [OSTI]

    Gleason, Shaun S. (Knoxville, TN); Hunt, Martin A. (Knoxville, TN); Sari-Sarraf, Hamed (Lubbock, TX)

    2002-01-01

    Automatic detection of defects during the fabrication of semiconductor wafers is largely automated, but the classification of those defects is still performed manually by technicians. This invention includes novel digital image analysis techniques that generate unique feature vector descriptions of semiconductor defects as well as classifiers that use these descriptions to automatically categorize the defects into one of a set of pre-defined classes. Feature extraction techniques based on multiple-focus images, multiple-defect mask images, and segmented semiconductor wafer images are used to create unique feature-based descriptions of the semiconductor defects. These feature-based defect descriptions are subsequently classified by a defect classifier into categories that depend on defect characteristics and defect contextual information, that is, the semiconductor process layer(s) with which the defect comes in contact. At the heart of the system is a knowledge database that stores and distributes historical semiconductor wafer and defect data to guide the feature extraction and classification processes. In summary, this invention takes as its input a set of images containing semiconductor defect information, and generates as its output a classification for the defect that describes not only the defect itself, but also the location of that defect with respect to the semiconductor process layers.

  6. Observation of lower to higher bandgap transition of one-dimensional defect modes

    E-Print Network [OSTI]

    Chen, Zhigang

    Observation of lower to higher bandgap transition of one-dimensional defect modes Xiaosheng Wang with a negative defect and observe linear bandgap guidance in such a defect. We show that a defect mode moves from and links 1. J. D. Joannopoulos, R. D. Meade, and J. N. Winn, Photonic Crystals: Molding the Flow of Light

  7. Use of relative code churn measures to predict system defect density

    E-Print Network [OSTI]

    Bae, Doo-Hwan

    Use of relative code churn measures to predict system defect density Nachiappan Nagappan and Thomas for potential defects Research goal · Create a set of relative code churn measures as early indicators of defects · Validate defect prediction power of the measures Code churn Measure of the amount of code change

  8. Systems and methods for forming defects on graphitic materials and curing radiation-damaged graphitic materials

    SciTech Connect (OSTI)

    Ryu, Sunmin; Brus, Louis E.; Steigerwald, Michael L.; Liu, Haitao

    2012-09-25

    Systems and methods are disclosed herein for forming defects on graphitic materials. The methods for forming defects include applying a radiation reactive material on a graphitic material, irradiating the applied radiation reactive material to produce a reactive species, and permitting the reactive species to react with the graphitic material to form defects. Additionally, disclosed are methods for removing defects on graphitic materials.

  9. 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.

  10. 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.

  11. Capturing skin properties from dynamic mechanical analyses

    E-Print Network [OSTI]

    Sandford, Erika J. (Erika Jaye)

    2012-01-01

    Existing skin mechanical testing devices focus on measuring skin elasticity and are not tailored to assess the dynamic behavior of skin. The mathematical techniques used to analyze data collected using these devices are ...

  12. Limitation of the Open-Circuit Voltage Due to Metastable Intrinsic Defects in Cu(In,Ga)Se2 and Strategies to Avoid These Defects: Preprint

    SciTech Connect (OSTI)

    Lany, S.; Zunger, A.

    2008-05-01

    This paper summarizes using first-principles defect theory to investigate the role of intrinsic point defects in the limitation of the open-circuit voltage (VOC) in Cu(In,Ga)Se2 solar cells.

  13. Defects and persistent conductivity in SrTiO{sub 3}

    SciTech Connect (OSTI)

    McCluskey, Matthew D.; Tarun, Marianne C.

    2014-02-21

    Strontium titanate (SrTiO{sub 3}) is often used as a substrate for oxide thin films such as high-temperature superconductors. It has the perovskite structure and an indirect band gap of 3.25 eV. Our prior work showed that hydrogen impurities form a defect complex that contains two hydrogen atoms. The complex was tentatively attributed to a passivated strontium vacancy. Alternatively, it could be a partially passivated titanium vacancy. In order to create titanium vacancies, we annealed samples in an evacuated ampoule with SrO powder. These samples show unexpected behavior. After illuminating with sub-gap light, the free-electron concentration increases significantly. After the light is turned off, the high conductivity persists at room temperature. We attribute persistent photoconductivity (PPC) to the excitation of an electron from a vacancy into the conduction band, with a low recapture rate.

  14. Predicting the Occurrence of Cosmetic Defects in Automotive Skin Panels

    SciTech Connect (OSTI)

    Hazra, S.; Williams, D.; Roy, R.; Aylmore, R.; Allen, M.; Hollingdale, D.

    2011-05-04

    The appearance of defects such as 'hollows' and 'shock lines' can affect the perceived quality and attractiveness of automotive skin panels. These defects are the result of the stamping process and appear as small, localized deviations from the intended styling of the panels. Despite their size, they become visually apparent after the application of paint and the perceived quality of a panel may become unacceptable. Considerable time is then dedicated to minimizing their occurrence through tool modifications. This paper will investigate the use of the wavelet transform as a tool to analyze physically measured panels. The transform has two key aspects. The first is its ability to distinguish small scale local defects from large scale styling curvature. The second is its ability to characterize the shape of a defect in terms of its wavelength and a 'correlation value'. The two features of the transform enable it to be used as a tool for locating and predicting the severity of defects. The paper will describe the transform and illustrate its application on test cases.

  15. Developmental defects in zebrafish for classification of EGF pathway inhibitors

    SciTech Connect (OSTI)

    Pruvot, Benoist; Curé, Yoann; Djiotsa, Joachim; Voncken, Audrey; Muller, Marc

    2014-01-15

    One of the major challenges when testing drug candidates targeted at a specific pathway in whole animals is the discrimination between specific effects and unwanted, off-target effects. Here we used the zebrafish to define several developmental defects caused by impairment of Egf signaling, a major pathway of interest in tumor biology. We inactivated Egf signaling by genetically blocking Egf expression or using specific inhibitors of the Egf receptor function. We show that the combined occurrence of defects in cartilage formation, disturbance of blood flow in the trunk and a decrease of myelin basic protein expression represent good indicators for impairment of Egf signaling. Finally, we present a classification of known tyrosine kinase inhibitors according to their specificity for the Egf pathway. In conclusion, we show that developmental indicators can help to discriminate between specific effects on the target pathway from off-target effects in molecularly targeted drug screening experiments in whole animal systems. - Highlights: • We analyze the functions of Egf signaling on zebrafish development. • Genetic blocking of Egf expression causes cartilage, myelin and circulatory defects. • Chemical inhibition of Egf receptor function causes similar defects. • Developmental defects can reveal the specificity of Egf pathway inhibitors.

  16. Plug Load Behavioral Change Demonstration Project

    SciTech Connect (OSTI)

    Metzger, I.; Kandt, A.; VanGeet, O.

    2011-08-01

    This report documents the methods and results of a plug load study of the Environmental Protection Agency's Region 8 Headquarters in Denver, Colorado, conducted by the National Renewable Energy Laboratory. The study quantified the effect of mechanical and behavioral change approaches on plug load energy reduction and identified effective ways to reduce plug load energy. Load reduction approaches included automated energy management systems and behavioral change strategies.

  17. 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...

  18. ME/BE523 Mechanics of Biomaterials Spring 2009 Departments of Mechanical and Biomedical Engineering, Boston University

    E-Print Network [OSTI]

    Lin, Xi

    ME/BE523 Mechanics of Biomaterials Spring 2009 Departments of Mechanical and Biomedical Engineering March 3 13 Measuring Viscoelastic Behavior Handouts Th March 5 14 Nanoindentation of Biomaterials

  19. 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

  20. Ultrasonic imaging system for in-process fabric defect detection

    DOE Patents [OSTI]

    Sheen, Shuh-Haw (Naperville, IL); Chien, Hual-Te (Naperville, IL); Lawrence, William P. (Downers Grove, IL); Raptis, Apostolos C. (Downers Grove, IL)

    1997-01-01

    An ultrasonic method and system are provided for monitoring a fabric to identify a defect. A plurality of ultrasonic transmitters generate ultrasonic waves relative to the fabric. An ultrasonic receiver means responsive to the generated ultrasonic waves from the transmitters receives ultrasonic waves coupled through the fabric and generates a signal. An integrated peak value of the generated signal is applied to a digital signal processor and is digitized. The digitized signal is processed to identify a defect in the fabric. The digitized signal processing includes a median value filtering step to filter out high frequency noise. Then a mean value and standard deviation of the median value filtered signal is calculated. The calculated mean value and standard deviation are compared with predetermined threshold values to identify a defect in the fabric.

  1. Thermodynamic stability of oxygen point defects in cubic Zirconia

    E-Print Network [OSTI]

    Samanta, Amit; Li, Ju

    2010-01-01

    Zirconia (ZrO2) is an important material with technological applications which are affected by point defect physics. Ab-initio calculations are performed to understand the structural and electronic properties of oxygen vacancies and interstitials in different charge states in cubic zirconia. We find oxygen interstitials in cubic ZrO2 can have five different configurations - dumbbell, dumbbell, crowd-ion, octahedral, and distorted dumbbell. For a neutral and singly charged oxygen interstitial, the lowest energy configuration is the dumbbell, while for a doubly charged oxygen interstitial the octahedral site is energetically the most favorable. Both the oxygen interstitial and the oxygen vacancy are negative-U, so that the singly charged defects are unstable at any Fermi level. The thermodynamic stability of these defects are studied in terms of Fermi level, oxygen partial pressure and temperature. A method to determine the chemical potential of the system as a function of temperature and pressure is propo...

  2. Correlation between the electronic structures and diffusion paths of interstitial defects in semiconductors: The case in CdTe

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

    Ma, Jie; Yang, Jihui; Da Silva, J. L.F.; Wei, Su-Huai

    2014-10-30

    Using first-principles calculations, we study the diffusions of interstitial defects Cd, Cu, Te, and Cl in CdTe. We find that the diffusion behavior is strongly correlated with the electronic structure of the interstitial diffuser. For Cd and Cu, because the defect state is the non-degenerated slike state under Td symmetry, the diffusions are almost along the [111] directions between the tetrahedral sites, although the diffusion of Cu shows some deviation due to the s - d coupling. The diffusions of the neutral and charged Cd and Cu follow similar paths. However, for Te and Cl atoms, because the defect statemore »is the degenerated p-like state under Td symmetry, large distortions occur. Therefore, the diffusion paths are very different from those of Cd and Cu interstitials, and depend strongly on the charge states of the interstitial atoms. For Te, we find that the distortion is mostly stabilized by the crystal-field splitting, but for Cl, the exchange splitting plays a more important role.« less

  3. Correlation between the electronic structures and diffusion paths of interstitial defects in semiconductors: The case in CdTe

    SciTech Connect (OSTI)

    Ma, Jie; Yang, Jihui; Da Silva, J. L.F.; Wei, Su-Huai

    2014-10-30

    Using first-principles calculations, we study the diffusions of interstitial defects Cd, Cu, Te, and Cl in CdTe. We find that the diffusion behavior is strongly correlated with the electronic structure of the interstitial diffuser. For Cd and Cu, because the defect state is the non-degenerated slike state under Td symmetry, the diffusions are almost along the [111] directions between the tetrahedral sites, although the diffusion of Cu shows some deviation due to the s - d coupling. The diffusions of the neutral and charged Cd and Cu follow similar paths. However, for Te and Cl atoms, because the defect state is the degenerated p-like state under Td symmetry, large distortions occur. Therefore, the diffusion paths are very different from those of Cd and Cu interstitials, and depend strongly on the charge states of the interstitial atoms. For Te, we find that the distortion is mostly stabilized by the crystal-field splitting, but for Cl, the exchange splitting plays a more important role.

  4. Correlation between the electronic structures and diffusion paths of interstitial defects in semiconductors: The case in CdTe

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

    Ma, Jie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Yang, Jihui [National Renewable Energy Lab. (NREL), Golden, CO (United States); Da Silva, J. L.F. [Univ. of Sao Paulo, Sao Carlos (Brazil). Sao Carlos Institute of Chemistry; Wei, Su-Huai [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-10-01

    Using first-principles calculations, we study the diffusions of interstitial defects Cd, Cu, Te, and Cl in CdTe. We find that the diffusion behavior is strongly correlated with the electronic structure of the interstitial diffuser. For Cd and Cu, because the defect state is the non-degenerated slike state under Td symmetry, the diffusions are almost along the [111] directions between the tetrahedral sites, although the diffusion of Cu shows some deviation due to the s - d coupling. The diffusions of the neutral and charged Cd and Cu follow similar paths. However, for Te and Cl atoms, because the defect state is the degenerated p-like state under Td symmetry, large distortions occur. Therefore, the diffusion paths are very different from those of Cd and Cu interstitials, and depend strongly on the charge states of the interstitial atoms. For Te, we find that the distortion is mostly stabilized by the crystal-field splitting, but for Cl, the exchange splitting plays a more important role.

  5. 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.

  6. 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.

  7. On the defect induced gauge and Yukawa fields in graphene

    E-Print Network [OSTI]

    Corneliu Sochichiu

    2011-03-08

    We consider lattice deformations (both continuous and topological) in the hexagonal lattice Hubbard model in the tight binding approximation to graphene, involving operators with the range up to next-to-neighbor. In the low energy limit, we find that these deformations give rise to couplings of the electronic Dirac field to an external scalar (Yukawa) and gauge fields. The fields are expressed in terms of original defects. As a by-product we establish that the next-to-nearest order is the minimal range of deformations which produces the complete gauge and scalar fields. We consider an example of Stone--Wales defect, and find the associated gauge field.

  8. Non-perturbative embedding of local defects in crystalline materials

    E-Print Network [OSTI]

    Eric Cances; Amelie Deleurence; Mathieu Lewin

    2008-01-09

    We present a new variational model for computing the electronic first-order density matrix of a crystalline material in presence of a local defect. A natural way to obtain variational discretizations of this model is to expand the difference Q between the density matrix of the defective crystal and the density matrix of the perfect crystal, in a basis of precomputed maximally localized Wannier functions of the reference perfect crystal. This approach can be used within any semi-empirical or Density Functional Theory framework.

  9. Generalized Defect Energy in a Gradient Plasticity Framework

    E-Print Network [OSTI]

    Bayerschen, E

    2015-01-01

    A gradient plasticity model is presented that includes a generalized, power-law type defect energy depending on the gradient of an equivalent plastic strain. Numerical regularization for the case of vanishing gradients is employed in the finite element discretization of the theory. Three exemplary choices of the defect energy exponent are compared in finite element simulations of elastic-plastic tricrystals under tensile loading. The influence of the power-law exponent is discussed related to the distribution of gradients and in regard to size effects. In addition, an analytical solution is presented for the single slip case and allows to interpret the numerical findings.

  10. On the material geometry of continuously defective corrugated graphene sheets

    E-Print Network [OSTI]

    Andrzej Trzesowski

    2014-12-22

    Geometrical objects describing the material geometry of continuously defective graphene sheets are introduced and their compatibility conditions are formulated. Effective edge dislocations embedded in the Riemann-Cartan material space and defined by their scalar density and by local Burgers vectors, are considered. The case of secondary curvature-type defects created by this distribution of dislocations is analysed in terms of the material space. The variational geometry of the material space closely related with the existence of a characteristic length parameter is proposed. The formula which describes, in a reference temperature, the influence of dislocations on the material Riemannian metric, is given.

  11. Spatial adiabatic passage processes in sonic crystals with linear defects

    E-Print Network [OSTI]

    Ricard Menchon-Enrich; Jordi Mompart; Veronica Ahufinger

    2014-02-19

    We investigate spatial adiabatic passage processes for sound waves propagation in sonic crystals, consisting of steel cylinders embedded in a water host medium, that present two linear defects. This work constitutes an extension of the well-known quantum optical rapid adiabatic passage technique to the field of sound propagation. Several spatial adiabatic passage devices are proposed, by appropriately designing the geometry of the two linear defects along the propagation direction, to work as a coherent multifrequency adiabatic splitter, a phase difference analyzer and a coherent multifrequency adiabatic coupler. These devices are robust in front of fluctuations of the geometric parameter values.

  12. Comment on Scattering-Matrix Method for Determining Defect Modes 

    E-Print Network [OSTI]

    Allen, Roland E.

    1971-01-01

    VOLU ME 3, NUMBER 10 15 MAY 1971 Comment on the Scattering-Matrix Method for Determining Defect Modes* R. E. Allen Department of Physics, University of Texas, Austin, Texas 78712 (Received 25 June 1970) It is pointed out that the formulation... of the scattering-matrix method given by Achar and Barsch, which was proposed and used for calculating localized modes at surfaces and other planar defects, is based on an incorrect assumption. A formulation of the scattering-matrix method for calculating...

  13. Electronic and magnetic properties of zigzag silicene nanoribbons with Stone–Wales defects

    SciTech Connect (OSTI)

    Dong, Haixia; Fang, Dangqi; Gong, Baihua; Zhang, Yang; Zhang, Erhu; Zhang, Shengli

    2015-02-14

    The structural, electronic, and magnetic properties of zigzag silicene nanoribbons (ZSiNRs) with Stone–Wales (SW) defects were investigated using first-principles calculations. We found that two types of SW defects (named SW-? and SW-??) exist in ZSiNRs. The SW defect was found to be the most stable at the edge of the ZSiNR, independently of the defect orientation, even more stable than it is in an infinite silicene sheet. In addition, the ZSiNRs can transition from semiconductor to metal or half-metal by modifying the SW defect location and concentration. For the same defect concentration, the band structures influenced by the SW-? defect are more distinct than those influenced by the SW-?? when the SW defect is at the edge. The present study suggests the possibility of tuning the electronic properties of ZSiNRs using the SW defects and might motivate their potential application in nanoelectronics and spintronics.

  14. Cracked-fuel mechanics. [PWR; BWR

    SciTech Connect (OSTI)

    Williford, R.E.; Lanning, D.D.

    1982-01-01

    This paper presents a modelling concept and a set of measurable parameters that have been shown to improve the prediction of the mechanical behavior of cracked fuel/cladding systems without added computational expense. The transition from classical annular gap/cylindrical pellet models to modified bulk properties and further to local behavior for cracked fuel systems is discussed. The results of laboratory experiments to verify these modelling parameters are shown. Data are also presented from laboratory experiments on unirradiated and irradiated rods which show that fuel rod mechanical response depends on fuel fragment size. The impact of these data on cracked fuel behavior and failure modelling is also discussed.

  15. Investigation into mechanical properties of bone and its main constituents

    E-Print Network [OSTI]

    Evdokimenko, Ekaterina

    2012-01-01

    treatment of intrabony periodontal defects: 6 year resultsbones, to repair periodontal defects, bone removal from

  16. Lattice Mechanics of Origami Tessellations

    E-Print Network [OSTI]

    Arthur A. Evans; Jesse L. Silverberg; Christian D. Santangelo

    2015-07-09

    Origami-based design holds promise for developing materials whose mechanical properties are tuned by crease patterns introduced to thin sheets. Although there has been heuristic developments in constructing patterns with desirable qualities, the bridge between origami and physics has yet to be fully developed. To truly consider origami structures as a class of materials, methods akin to solid mechanics need to be developed to understand their long-wavelength behavior. We introduce here a lattice theory for examining the mechanics of origami tessellations in terms of the topology of their crease pattern and the relationship between the folds at each vertex. This formulation provides a general method for associating mechanical properties with periodic folded structures, and allows for a concrete connection between more conventional materials and the mechanical metamaterials constructed using origami-based design.

  17. Characterization of fold defects in AZ91D and AE42 magnesium alloy permanent mold castings

    SciTech Connect (OSTI)

    Bichler, L. [Centre for Near-net-shape Processing of Materials, Ryerson University, 101 Gerrard St. E., Toronto, M5B 2K3 (Canada); Ravindran, C., E-mail: rravindr@ryerson.ca [Centre for Near-net-shape Processing of Materials, Ryerson University, 101 Gerrard St. E., Toronto, M5B 2K3 (Canada)

    2010-03-15

    Casting premium-quality magnesium alloy components for aerospace and automotive applications poses unique challenges. Magnesium alloys are known to freeze rapidly prior to filling a casting cavity, resulting in misruns and cold shuts. In addition, melt oxidation, solute segregation and turbulent metal flow during casting contribute to the formation of fold defects. In this research, formation of fold defects in AZ91D and AE42 magnesium alloys cast via the permanent mold casting process was investigated. Computer simulations of the casting process predicted the development of a turbulent metal flow in a critical casting region with abrupt geometrical transitions. SEM and light optical microscopy examinations revealed the presence of folds in this region for both alloys. However, each alloy exhibited a unique mechanism responsible for fold formation. In the AZ91D alloy, melt oxidation and velocity gradients in the critical casting region prevented fusion of merging metal front streams. In the AE42 alloy, limited solubility of rare-earth intermetallic compounds in the {alpha}-Mg phase resulted in segregation of Al{sub 2}RE particles at the leading edge of a metal front and created microstructural inhomogeneity across the fold.

  18. Proceedings of NAMRI/SME, Vol. 41, 2013 Removal Mechanism and Defect Characterization for Glass-

    E-Print Network [OSTI]

    Yao, Y. Lawrence

    impediment to large-scale adoption of solar power is its high production cost (price-per-watt) comparedTe, solar cell INTRODUCTION Thin-film solar cell technology promises to achieve a significant cost reduction- Side Laser Scribing of CdTe/CdS Multilayer in Solar Cells Hongliang Wang, Y. Lawrence Yao Department

  19. Transport and Defect Mechanisms in Cuprous Delafossites. 1. Comparison of Hydrothermal and

    E-Print Network [OSTI]

    Poeppelmeier, Kenneth R.

    flat-panel displays, ultraviolet light emitting diodes, heterojunctions for solar cells, and all- oxide are utilized in a variety of commercial applications, such as flat-panel displays, photovoltaic devices there are no commercially viable p-type TCOs. The development of a high figure-of-merit p-type TCO would enable improved

  20. Mechanical Analysis of the Nb3Sn Dipole Magnet HD1

    E-Print Network [OSTI]

    Ferracin, Paolo

    2008-01-01

    7] J. Strait, et al. , “Mechanical behavior of Fermilab-9] J. Buckley, et al. , “Mechanical performance of a twin-S. Caspi, et al. , “Mechanical design of a second generation

  1. Regulation mechanisms in spatial stochastic development models

    E-Print Network [OSTI]

    Dmitri Finkelshtein; Yuri Kondratiev

    2008-09-04

    The aim of this paper is to analyze different regulation mechanisms in spatial continuous stochastic development models. We describe the density behavior for models with global mortality and local establishment rates. We prove that the local self-regulation via a competition mechanism (density dependent mortality) may suppress a unbounded growth of the averaged density if the competition kernel is superstable.

  2. Nanoparticle halos: A new colloid stabilization mechanism

    E-Print Network [OSTI]

    Braun, Paul

    Nanoparticle halos: A new colloid stabilization mechanism Valeria Tohver*, James E. Smay*, Alan, 2001 (received for review February 7, 2001) A new mechanism for regulating the stability of colloidal for tailoring the behavior of com- plex fluids. Colloidal suspensions enjoy widespread use in applications

  3. Kibble-Zurek mechanism in colloidal monolayers

    E-Print Network [OSTI]

    Sven Deutschländer; Patrick Dillmann; Georg Maret; Peter Keim

    2015-03-30

    The Kibble-Zurek mechanism describes the evolution of topological defect structures like domain walls, strings, and monopoles when a system is driven through a second order phase transition. The model is used on very different scales like the Higgs field in the early universe or quantum fluids in condensed matter systems. A defect structure naturally arises during cooling if separated regions are too far apart to `communicate' (e.g. about their orientation or phase) due to finite signal velocity. This results in separated domains with different (degenerated) locally broken symmetry. Within this picture we investigate the non-equilibrium dynamics in a condensed matter analogue, a two-dimensional ensemble of colloidal particles. In equilibrium it obeys the so called Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) melting scenario with continuous (second-order like) phase transitions. The ensemble is exposed to a set of finite cooling rates covering roughly three orders of magnitude. Along this process, we analyze the defect and domain structure quantitatively via video microscopy and determine the scaling of the corresponding length scales as a function of the cooling rate. We indeed observe the scaling predicted by the Kibble-Zurek mechanism for the KTHNY universality class.

  4. Defect Tolerance in VLSI Circuits: Techniques and Yield Analysis

    E-Print Network [OSTI]

    Koren, Israel

    severity grows proportionally with the size and density of the chip. Consequently, the development and use as the proportion of operational circuits to the total number of fabricated circuits. A yield of 100% is unlikely, due to various manufacturing defects that exist even under mature manufacturing conditions. Continuous

  5. Modeling of three dimensional defects in integrated circuits 

    E-Print Network [OSTI]

    Dani, Sameer Manohar

    1993-01-01

    properties that result from the interaction between the IC and the defect size in two coordinate spaces: x-y and z. The approach is a natural extension to the concept of critical areas, namely, the extraction of critical volumes. Through the course...

  6. 2005 May JOM 35 Casting DefectsOverview

    E-Print Network [OSTI]

    Haller, Gary L.

    2005 May · JOM 35 Casting DefectsOverview Superplastic forming (SPF) is intro- duced must fill the entire mold cavity and at the same time be cooled fast enough to avoidcrystallization.Thismakescasting of complex geometries (i.e., parts with thin sections and large aspect ratios) a challenging undertaking

  7. Automatic Detection of Defects in Riveted Lapjoints using Eddy Current

    E-Print Network [OSTI]

    Automatic Detection of Defects in Riveted Lap­joints using Eddy Current Fredrik Lingvall Tadeusz originating from rivet holes in a riveted lap­joint using eddy current (EC) inspection is presented consisted of median filtering, rotation and de­biasing of the eddy current pattern. The rotation

  8. Nature of Radiation-Induced Defects in Quartz

    E-Print Network [OSTI]

    Bu Wang; Yingtian Yu; Isabella Pignatelli; Gaurav N. Sant; Mathieu Bauchy

    2015-04-10

    Although quartz ($\\rm \\alpha$-form) is a mineral used in numerous applications wherein radiation exposure is an issue, the nature of the atomistic defects formed during radiation-induced damage have not been fully clarified. Especially, the extent of oxygen vacancy formation is still debated, which is an issue of primary importance as optical techniques based on charged oxygen vacancies have been utilized to assess the level of radiation damage in quartz. In this paper, molecular dynamics (MD) simulations are applied to study the effects of ballistic impacts on the atomic network of quartz. We show that the defects that are formed mainly consist of over-coordinated Si and O, as well as Si--O connectivity defects, e.g., small Si--O rings and edge-sharing Si tetrahedra. Oxygen vacancies, on the contrary, are found in relatively low abundance, suggesting that characterizations based on $E^{\\prime}$ centers do not adequately capture radiation-induced structural damage in quartz. Finally, we evaluate the dependence on the incident energy, of the amount of each type of the point defects formed, and quantify unambiguously the threshold displacement energies for both O and Si atoms. These results provide a comprehensive basis to assess the nature and extent of radiation damage in quartz.

  9. On the conservation of software defect CISM, University of Kingston

    E-Print Network [OSTI]

    Hatton, Les

    , T the temperature and R the gas constant is astonishingly accurate over a very wide range of pressures, then commonly used defect models for individual components directly im- ply that the distribution of component systems extremely accurately. For example, for a gas, PV = RT where P is the pressure, V the volume

  10. Fast non-iterative methods for defect identification

    E-Print Network [OSTI]

    Guzina, Bojan

    Fast non-iterative methods for defect identification Marc Bonnet -- Bojan B. Guzina -- Nicolas and topology by means of the concept of topological sensitivity. This approach leads to the fast computation is obtained by using fast multipole accelerated BEMs. Possibilities afforded by this approach are demon

  11. Simulations of Deep-Level Defects in Semiconductors

    E-Print Network [OSTI]

    Jones, Robert

    ( Z Y X v = 1 2f1 +2 +3 +4g;tx = 1 2f1 +2 ,3 ,4g 19 4 1999 4 #12;A. Resende AIMPRO Group ENDEASD. European Network on Defect Engineering of Advanced Semiconductor Devices ENDEASD #12;A. Resende AIMPRO

  12. Infrared photothermal radiometry of deep subsurface defects in semiconductor materials

    E-Print Network [OSTI]

    Mandelis, Andreas

    Infrared photothermal radiometry of deep subsurface defects in semiconductor materials M. E. Rodri sensitivity to the electronic transport properties of the laser photoexcited material.3 Using two information. INTRODUCTION The nondestructive, nonintrusive evaluation of semicon- ductor materials has been of common

  13. AutoODC: Automated Generation of Orthogonal Defect Classifications

    E-Print Network [OSTI]

    Ng, Vincent

    data are reported by users or developers during system development, operation and maintenance valuable in-process feedback to system development and maintenance. Conducting ODC classification classification and analysis of defect data bridge the gap between causal analysis and statistical quality control

  14. AutoODC: Automated Generation of Orthogonal Defect Classifications

    E-Print Network [OSTI]

    Ng, Vincent

    data are reported by users or developers during system development, operation and maintenance and analysis, provides valuable in­process feedback to system development and maintenance. Conducting ODC classification and analysis of defect data bridge the gap between causal analysis and statistical quality control

  15. An Empirical Comparison of Field Defect Modeling Methods

    E-Print Network [OSTI]

    operating system as judged by the Theil forecasting statistic (explained in section 4). We conjecture about Management, Measurement, Reliability, Experimentation, Defect modeling, empirical research, COTS, maintenance-based and metrics-based approach, as judged by the Theil forecasting statistic. We suggest possible conditions

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

    E-Print Network [OSTI]

    Krivtsov, Anton M.

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

  17. Nanocrystalline alloys : enhanced strengthening mechanisms and mechanically-driven structural evolution

    E-Print Network [OSTI]

    Rupert, Timothy J. (Timothy John)

    2011-01-01

    Nanocrystalline materials have experienced a great deal of attention in recent years, largely due to their impressive array of physical properties. In particular, nanocrystalline mechanical behavior has been of interest, ...

  18. Applications of Admittance Spectroscopy in Photovoltaic Devices Beyond Majority Carrier Trapping Defects: Preprint

    SciTech Connect (OSTI)

    Li, J. V.; Crandall, R. S.; Repins, I. L.; Nardes, A. M.; Levi, D. H.; Sulima, O.

    2011-07-01

    Admittance spectroscopy is commonly used to characterize majority-carrier trapping defects. In today's practical photovoltaic devices, however, a number of other physical mechanisms may contribute to the admittance measurement and interfere with the data interpretation. Such challenges arise due to the violation of basic assumptions of conventional admittance spectroscopy such as single-junction, ohmic contact, highly conductive absorbers, and measurement in reverse bias. We exploit such violations to devise admittance spectroscopy-based methods for studying the respective origins of 'interference': majority-carrier mobility, non-ohmic contact potential barrier, minority-carrier inversion at hetero-interface, and minority-carrier lifetime in a device environment. These methods are applied to a variety of photovoltaic technologies: CdTe, Cu(In,Ga)Se2, Si HIT cells, and organic photovoltaic materials.

  19. The effect of defect introduction vs. load application sequencing on defect-induced stress distributions in steel samples

    E-Print Network [OSTI]

    Clapham, Lynann

    of Canada, Chalk River, Ontario, Canada K0J 1J0 Received 16 October 1998; received in revised form 20 May is needed to convert the MFL signal amplitudes into defect dimensions. When performing such calibration runs optimized. This is achieved by having th

  20. Deformation Mechanisms in Compression-Loaded, Stand-Alone Plasma-Sprayed Alumina Coatings

    E-Print Network [OSTI]

    Trice, Rodney W.

    Deformation Mechanisms in Compression-Loaded, Stand-Alone Plasma-Sprayed Alumina Coatings Rodney W. It is proposed that the numerous defects in plasma- sprayed coatings, including porosity and microcracks, serve-SPRAYED coatings are frequently used as thermal-barrier coatings (TBCs) or wear-resistant coatings. Mechanical

  1. Reproductive/Social Behavior Undergraduate Honors Thesis

    E-Print Network [OSTI]

    Fernald, Russell

    Kelly Eaton Neural mechanisms of parental care and filial cannibalism in female fish 2010 Catherine Harrell Interactive behavior research with a virtual cichlid fish 2010 Hong-An Nguyen The role of excitatory synaptic inputs in the social regulation of preoptic area neurons in the cichlid fish

  2. Inorganic-Organic Shape Memory Polymers and Foams for Bone Defect Repairs 

    E-Print Network [OSTI]

    Zhang, Dawei

    2013-04-16

    The ultimate goal of this research was to develop a “self-fitting” shape memory polymer (SMP) scaffold for the repair of craniomaxillofacial (CMF) bone defects. CMF defects may be caused by trauma, tumor removal or congenital abnormalities...

  3. Deformation Behavior of Laser Welds in High Temperature Oxidation Resistant Fe-Cr-Al Alloys for Fuel Cladding Applications

    SciTech Connect (OSTI)

    Field, Kevin G; Gussev, Maxim N; Yamamoto, Yukinori; Snead, Lance Lewis

    2014-11-01

    Ferritic-structured Fe-Cr-Al alloys are being developed and show promise as oxidation resistant accident tolerant light water reactor fuel cladding. This study focuses on investigating the weldability of three model alloys in a range of Fe-(13-17.5)Cr-(3-4.4)Al in weight percent with a minor addition of yttrium using laser-welding techniques. A detailed study on the mechanical performance of bead-on-plate welds has been carried out to determine the performance of welds as a function of alloy composition. Laser welding resulted in a defect free weld devoid of cracking or inclusions for all alloys studied. Results indicated a reduction in the yield strength within the fusion zone compared to the base metal. Yield strength reduction was found to be primarily constrained to the fusion zone due to grain coarsening with a less severe reduction in the heat affected zone. No significant correlation was found between the deformation behavior/mechanical performance of welds and the level of Cr or Al in the alloy ranges studied.

  4. Optimizing Test Pattern Generation Using Top-Off ATPG Methodology for Stuck–AT, Transition and Small Delay Defect Faults 

    E-Print Network [OSTI]

    Gill, Arjun

    2013-05-01

    of ATPG to not only include the conventional static defects but also to include test patterns for dynamic defects. The current industry practices consider test pattern generation for transition faults to screen dynamic defects. It has been observed...

  5. Deformation Behavior of Sub-micron and Micron Sized Alumina Particles in Compression.

    SciTech Connect (OSTI)

    Sarobol, Pylin; Chandross, Michael E.; Carroll, Jay; Mook, William; Boyce, Brad; Kotula, Paul G.; McKenzie, Bonnie B.; Bufford, Daniel Charles; Hall, Aaron Christopher.

    2014-09-01

    The ability to integrate ceramics with other materials has been limited due to high temperature (>800degC) ceramic processing. Recently, researchers demonstrated a novel process , aerosol deposition (AD), to fabricate ceramic films at room temperature (RT). In this process, sub - micro n sized ceramic particles are accelerated by pressurized gas, impacted on the substrate, plastically deformed, and form a dense film under vacuum. This AD process eliminates high temperature processing thereby enabling new coatings and device integration, in which ceramics can be deposited on metals, plastics, and glass. However, k nowledge in fundamental mechanisms for ceramic particle s to deform and form a dense ceramic film is still needed and is essential in advancing this novel RT technology. In this wo rk, a combination of experimentation and atomistic simulation was used to determine the deformation behavior of sub - micron sized ceramic particle s ; this is the first fundamental step needed to explain coating formation in the AD process . High purity, singl e crystal, alpha alumina particles with nominal size s of 0.3 um and 3.0 um were examined. Particle characterization, using transmission electron microscopy (TEM ), showed that the 0.3 u m particles were relatively defect - free single crystals whereas 3.0 u m p articles were highly defective single crystals or particles contained low angle grain boundaries. Sub - micron sized Al 2 O 3 particles exhibited ductile failure in compression. In situ compression experiments showed 0.3um particles deformed plastically, fractured, and became polycrystalline. Moreover, dislocation activit y was observed within the se particles during compression . These sub - micron sized Al 2 O 3 particles exhibited large accum ulated strain (2 - 3 times those of micron - sized particles) before first fracture. I n agreement with the findings from experimentation , a tomistic simulation s of nano - Al 2 O 3 particles showed dislocation slip and significant plastic deformation during compressi on . On the other hand, the micron sized Al 2 O 3 particles exhibited brittle f racture in compression. In situ compression experiments showed 3um Al 2 O 3 particles fractured into pieces without observable plastic deformation in compression. Particle deformation behaviors will be used to inform Al 2 O 3 coating deposition parameters and particle - particle bonding in the consolidated Al 2 O 3 coatings.

  6. Derivation of evolutionary payoffs from observable behavior

    E-Print Network [OSTI]

    Feigel, Alexander; Engel, Assaf

    2008-01-01

    Interpretation of animal behavior, especially as cooperative or selfish, is a challenge for evolutionary theory. Strategy of a competition should follow from corresponding Darwinian payoffs for the available behavioral options. The payoffs and decision making processes, however, are difficult to observe and quantify. Here we present a general method for the derivation of evolutionary payoffs from observable statistics of interactions. The method is applied to combat of male bowl and doily spiders, to predator inspection by sticklebacks and to territorial defense by lions, demonstrating animal behavior as a new type of game theoretical equilibrium. Games animals play may be derived unequivocally from their observable behavior, the reconstruction, however, can be subjected to fundamental limitations due to our inability to observe all information exchange mechanisms (communication).

  7. Defects in Ge and Si caused by 1 MeV Si+ implantation*

    E-Print Network [OSTI]

    Florida, University of

    Defects in Ge and Si caused by 1 MeV Si+ implantation* D. P. Hickeya Department of Materials defect formation and evolution in the 001 Ge and Si wafers implanted with 1 MeV Si+ and 40 keV Si dissolve at the projected range for nonamorphizing implants into Si. However, in Ge, no 311 defect

  8. Software Defect Data and Predictability for Testing Schedules Rattikorn Hewett & Aniruddha Kulkarni

    E-Print Network [OSTI]

    Stringfellow, Catherine V.

    Software Defect Data and Predictability for Testing Schedules Rattikorn Hewett & Aniruddha Kulkarni of resources. As software gets more complex, testing and fixing defects become difficult to schedule. This paper attempts to predict an estimated time for fixing software defects found during testing processes

  9. Ian Sommerville 2000 Software Engineering, 6th edition. Chapter 20 Slide 1 Defect testing

    E-Print Network [OSTI]

    Scharff, Christelle

    ©Ian Sommerville 2000 Software Engineering, 6th edition. Chapter 20 Slide 1 Defect testing l Testing programs to establish the presence of system defects #12;©Ian Sommerville 2000 Software Sommerville 2000 Software Engineering, 6th edition. Chapter 20 Slide 3 Topics covered l Defect testing l

  10. DISSERTATION THE EFFECT OF TRAPPING DEFECTS ON CIGS SOLAR-CELL

    E-Print Network [OSTI]

    Sites, James R.

    DISSERTATION THE EFFECT OF TRAPPING DEFECTS ON CIGS SOLAR-CELL PERFORMANCE Submitted by Pamela K ENTITLED THE EFFECT OF TRAPPING DEFECTS ON CIGS SOLAR-CELL PERFORMANCE BE ACCEPTED AS FULFILLING IN PART RE OF DISSERTATION THE EFFECT OF TRAPPING DEFECTS ON CIGS SOLAR-CELL PERFORMANCE The relationship between basic solar-cell

  11. Robotic Tracking and Marking of Surface Shape Defects on Moving Automotive Panels

    E-Print Network [OSTI]

    Payeur, Pierre

    Robotic Tracking and Marking of Surface Shape Defects on Moving Automotive Panels Valentin Borsu defects for quality control in the automotive industry. In order to integrate a defects detection station. INTRODUCTION Quality control in the automotive industry is essential in order to ensure that the products meet

  12. Health Behavior Health Promotion -Prevention

    E-Print Network [OSTI]

    Meagher, Mary

    Health Behavior Health Promotion - Prevention Modification of Health Attitudes and Health Behavior #12;Health Promotion: An Overview Basic philosophy Good health = individual and collective goal interventions Public Health Strategies #12;Introduction to Health Behaviors: Role of Behavioral Factors

  13. 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.

  14. Native defects in MBE-grown CdTe

    SciTech Connect (OSTI)

    Olender, Karolina; Wosinski, Tadeusz; Makosa, Andrzej; Tkaczyk, Zbigniew; Kolkovsky, Valery; Karczewski, Grzegorz

    2013-12-04

    Deep-level traps in both n- and p-type CdTe layers, grown by molecular-beam epitaxy on GaAs substrates, have been investigated by means of deep-level transient spectroscopy (DLTS). Four of the traps revealed in the DLTS spectra, which displayed exponential kinetics for capture of charge carriers into the trap states, have been assigned to native point defects: Cd interstitial, Cd vacancy, Te antisite defect and a complex formed of the Te antisite and Cd vacancy. Three further traps, displaying logarithmic capture kinetics, have been ascribed to electron states of treading dislocations generated at the mismatched interface with the substrate and propagated through the CdTe layer.

  15. Accessing defect dynamics using intense, nanosecond pulsed ion beams

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

    Persaud, A.; Barnard, J. J.; Guo, H.; Hosemann, P.; Lidia, S.; Minor, A. M.; Seidl, P. A.; Schenkel, T.

    2015-06-18

    Gaining in-situ access to relaxation dynamics of radiation induced defects will lead to a better understanding of materials and is important for the verification of theoretical models and simulations. We show preliminary results from experiments at the new Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory that will enable in-situ access to defect dynamics through pump-probe experiments. Here, the unique capabilities of the NDCX-II accelerator to generate intense, nanosecond pulsed ion beams are utilized. Preliminary data of channeling experiments using lithium and potassium ions and silicon membranes are shown. We compare these data to simulation results using Crystalmore »Trim. Furthermore, we discuss the improvements to the accelerator to higher performance levels and the new diagnostics tools that are being incorporated.« less

  16. Doping-assisted defect control in compound semiconductors

    DOE Patents [OSTI]

    Specht, Petra; Weber, Eicke R.; Weatherford, Todd Russell

    2006-07-11

    The present invention relates to the production of thin film epilayers of III–V and other compounds with acceptor doping wherein the acceptor thermally stabilizes the epilayer, stabilize the naturally incorporated native defect population and therewith maintain the epilayer's beneficial properties upon annealing among other advantageous effects. In particular, balanced doping in which the acceptor concentration is similar to (but does not exceed) the antisite defects in the as-grown material is shown to be particularly advantageous in providing thermal stability, high resistivity and ultrashort trapping times. In particular, MBE growth of LT-GaAs epilayers with balanced Be doping is described in detail. The growth conditions greatly enhance the materials reproducibility (that is, the yield in processed devices). Such growth techniques can be transferred to other III–V materials if the growth conditions are accurately reproduced. Materials produced herein also demonstrate advantages in reproducibility, reliability and radiation hardening.

  17. Accessing defect dynamics using intense, nanosecond pulsed ion beams

    SciTech Connect (OSTI)

    Persaud, A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Barnard, J. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Guo, H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hosemann, P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Lidia, S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Minor, A. M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Seidl, P. A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schenkel, T. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-01-01

    Gaining in-situ access to relaxation dynamics of radiation induced defects will lead to a better understanding of materials and is important for the verification of theoretical models and simulations. We show preliminary results from experiments at the new Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory that will enable in-situ access to defect dynamics through pump-probe experiments. Here, the unique capabilities of the NDCX-II accelerator to generate intense, nanosecond pulsed ion beams are utilized. Preliminary data of channeling experiments using lithium and potassium ions and silicon membranes are shown. We compare these data to simulation results using Crystal Trim. Furthermore, we discuss the improvements to the accelerator to higher performance levels and the new diagnostics tools that are being incorporated.

  18. Defect density and dielectric constant in perovskite solar cells

    SciTech Connect (OSTI)

    Samiee, Mehran; Konduri, Siva; Abbas, Hisham A.; Joshi, Pranav; Zhang, Liang; Dalal, Vikram; Ganapathy, Balaji; Kottokkaran, Ranjith; Noack, Max; Kitahara, Andrew

    2014-10-13

    We report on measurement of dielectric constant, mid-gap defect density, Urbach energy of tail states in CH{sub 3}NH{sub 3}PbI{sub x}Cl{sub 1?x} perovskite solar cells. Midgap defect densities were estimated by measuring capacitance vs. frequency at different temperatures and show two peaks, one at 0.66?eV below the conduction band and one at 0.24?eV below the conduction band. The attempt to escape frequency is in the range of 2?×?10{sup 11}/s. Quantum efficiency data indicate a bandgap of 1.58?eV. Urbach energies of valence and conduction band are estimated to be ?16 and ?18?meV. Measurement of saturation capacitance indicates that the relative dielectric constant is ?18.

  19. Rate-dependent deformation behavior of poss-filled and plasticized poly(vinyl chloride)

    E-Print Network [OSTI]

    Soong, Sharon Yu-Wen

    2007-01-01

    Polymers are known to exhibit strong time-dependent mechanical behavior. In different temperatures or frequency regimes, the rate sensitivities of polymers change as various primary and secondary molecular mobility mechanisms ...

  20. Ab initio studies of niobium defects in uranium

    SciTech Connect (OSTI)

    Xiang, S; Huang, H; Hsiung, L

    2007-06-01

    Uranium (U), with the addition of small amount of niobium (Nb), is stainless. The Nb is fully miscible with the high temperature phase of U and tends to segregate upon cooling below 647 C. The starting point of segregation is the configuration of Nb substitutional or interstitial defects. Using density-functional-theory based ab initio calculations, the authors find that the formation energy of a single vacancy is 1.08 eV, that of Nb substitution is 0.59 eV, that of Nb interstitial at octahedral site is 1.58 eV, and that of Nb interstitial at tetrahedral site is 2.35 eV; all with reference to a reservoir of {gamma} phase U and pure Nb. The formation energy of Nb defects correlates with the local perturbation of electron distribution; higher formation energy to larger perturbation. Based on this study, Nb atoms thermodynamically prefer to occupy substitutional sites in {gamma} phase U, and they prefer to be in individual substitutional defects than clusters.

  1. Realizing the fusion rules of Ising anyons without lattice defects

    E-Print Network [OSTI]

    Ferreira, Miguel Jorge Bernabe; Teotonio-Sobrinho, Paulo

    2015-01-01

    Topologically ordered phases in two dimensions are characterized by their low energy excitations which are called anyons. These anyons are labeled by a set of anyon labels which can be braided and fused. These fusion and braiding properties can remain invariant under certain permutations of these anyon labels which generate an anyon symmetry group. In the example of the toric code this anyon symmetry manifests itself in the exchange of the charge, $e$ and flux, $m$ particles which is nothing but the electric-magnetic duality of the toric code model of Kitaev. However this is a global symmetry of the theory. It was shown to occur locally by the introduction of lattice defects which in turn induces a change in the toric code Hamiltonian along the defect. Here we introduce an exactly solvable model which achieves the local $e$-$m$ exchange without any modification to the lattice in the form of dislocations. However the Hamiltonian is still changed locally in what we call defect sites.These induce the permutation...

  2. 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

  3. Penta-hepta defect chaos in a model for rotating hexagonal convection

    E-Print Network [OSTI]

    Yuan-Nan Young; Hermann Riecke

    2002-09-19

    In a model for rotating non-Boussinesq convection with mean flow we identify a regime of spatio-temporal chaos that is based on a hexagonal planform and is sustained by the {\\it induced nucleation} of dislocations by penta-hepta defects. The probability distribution function for the number of defects deviates substantially from the usually observed Poisson-type distribution. It implies strong correlations between the defects inthe form of density-dependent creation and annihilation rates of defects. We extract these rates from the distribution function and also directly from the defect dynamics.

  4. Essays in behavioral economics

    E-Print Network [OSTI]

    Eil, David Holding

    2011-01-01

    Essays in Behavioral Economics A dissertation submitted inDoctor of Philosophy in Economics by David Holding Eilfunction,” The Review of Economics and Statistics, 1995,

  5. Method for characterizing mask defects using image reconstruction from X-ray diffraction patterns

    DOE Patents [OSTI]

    Hau-Riege, Stefan Peter (Fremont, CA)

    2007-05-01

    The invention applies techniques for image reconstruction from X-ray diffraction patterns on the three-dimensional imaging of defects in EUVL multilayer films. The reconstructed image gives information about the out-of-plane position and the diffraction strength of the defect. The positional information can be used to select the correct defect repair technique. This invention enables the fabrication of defect-free (since repaired) X-ray Mo--Si multilayer mirrors. Repairing Mo--Si multilayer-film defects on mask blanks is a key for the commercial success of EUVL. It is known that particles are added to the Mo--Si multilayer film during the fabrication process. There is a large effort to reduce this contamination, but results are not sufficient, and defects continue to be a major mask yield limiter. All suggested repair strategies need to know the out-of-plane position of the defects in the multilayer.

  6. Fusion Engineering and Design 82 (2007) 22332238 Application of discrete element method to study mechanical

    E-Print Network [OSTI]

    Abdou, Mohamed

    2007-01-01

    Fusion Engineering and Design 82 (2007) 2233­2238 Application of discrete element method to study mechanical behaviors of ceramic breeder pebble beds Zhiyong An, Alice Ying, Mohamed Abdou Mechanical In this paper, the discrete element method (DEM) approach has been applied to study mechanical behaviors

  7. 2210 IEEE TRANSACTIONS ON MAGNETICS, VOL. 37, NO. 4, JULY 2001 Synthesis, Structural Order and Magnetic Behavior of

    E-Print Network [OSTI]

    Krishnan, Kannan M.

    of the nanocrystals were controlled by varying the surfactant, its concentration, the reaction rate and the reaction into ordered arrays and their magnetic behavior as a function of structural order (ferrofluids and 2D temperature. The Co particles are defect-free single crystals with a complex cubic structure related

  8. Mechanical effects in cookoff modeling

    SciTech Connect (OSTI)

    Gross, R.J.; Baer, M.R.; Hobbs, M.L.

    1994-07-01

    Complete cookoff modeling of energetic material in confined geometries must couple thermal, chemical and mechanical effects. In the past, modeling has focused on the prediction of the onset of combustion behavior based only on thermal-chemistry effects with little or no regard to the mechanical behavior of the energetic material. In this paper, an analysis tool is outlined which couples thermal, chemical, and mechanical behavior for one-dimensional Geometries comprised of multi-materials. A reactive heat flow code, XCHEM, and a quasistatic mechanics code, SANTOS, have been completely coupled using, a reactive, elastic-plastic constitutive model describing pressurization of the energetic material. This new Thermally Reactive Elastic-plastic explosive code, TREX, was developed to assess the coupling, of mechanics with thermal chemistry making multidimensional cookoff analysis possible. In this study, TREX is applied to confined and unconfined systems. The confined systems simulate One-Dimensional Time to explosion (ODTX) experiments in both spherical and cylindrical configurations. The spherical ODTX system is a 1.27 cm diameter sphere of TATB confined by aluminum exposed to a constant external temperature. The cylindrical ODTX system is an aluminum tube filled with HMX, NC, and inert exposed to a constant temperature bath. Finally. an unconfined system consisting of a hollow steel cylinder filled with a propellant composed of Al, RMX, and NC, representative of a rocket motor, is considered. This model system is subjected to transient internal and external radiative/convective boundary conditions representative of 5 minutes exposure to a fire. The confined systems show significant pressure prior to ignition, and the unconfined system shows extrusion of the propellent suggesting that the energetic material becomes more shock sensitive.

  9. Genomic response, bioinformatics, and mechanics of the effects of forces on tissues and wound healing

    E-Print Network [OSTI]

    Saxena, Vishal, 1971-

    2005-01-01

    The mechanical environment of the cell is important for changes in behavior. Cellular behavioral changes can be traced to gene expression profile changes. These effects were studied in the context of Micromechanical force ...

  10. High Burnup Fuel Behavior Modeling

    SciTech Connect (OSTI)

    Jahingir, M.; Rand, R.; Stachowski, R.; Miles, B.; Kusagaya, K.

    2007-07-01

    This paper discusses the development and qualification of the PRIME03 code to address high burnup mechanisms and to improve uranium utilization in current and new reactor designs. Materials properties and behavioral models have been updated from previous thermal-mechanical codes to reflect the effects of burnup on fuel pellet thermal conductivity, Zircaloy creep, fuel pellet relocation, and fission gas release. These new models are based on results of in-pool and post irradiation examination (PIE) of commercial boiling water reactor (BWR) fuel rods at high burnup and results from international experimental programs. The new models incorporated into PRIME03 also address specific high burnup effects associated with formation of pellet rim porosity at high exposure. The PRIME03 code is qualified by comparison of predicted and measured fuel performance parameters for a large number of high, low, and moderate burnup test and commercial reactor rod. The extensive experimental qualification of the PRIME03 prediction capabilities confirms that it is a reliable best-estimate predictor of fuel rod thermal-mechanical performance over a wide range of design and operating conditions. (authors)

  11. 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

  12. Mechanisms Behind the Generalized Synchronization Conditions

    E-Print Network [OSTI]

    A. A. Koronovskii; O. I. Moskalenko; A. E. Hramov

    2006-02-25

    A universal mechanism underlying generalized synchronization conditions in unidirectionally coupled stochastic oscillators is considered. The consideration is carried out in the framework of a modified system with additional dissipation. The approach developed is illustrated with model examples. The conclusion is reached that two types of the behavior of nonlinear dynamic systems known as generalized synchronization and noise-induced synchronization, which are viewed as different phenomena, actually represent a unique type of the synchronous behavior of stochastic oscillators and are caused by the same mechanism.

  13. 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

  14. 1 Semst 8 Semth7 Semth6 Semth5 Semth4 Semth3 Semrd2 Semnd Mechanical and Industrial Engineering Department

    E-Print Network [OSTI]

    Mountziaris, T. J.

    Engineering MIE 570 Solar & Dir. Energy Conver. MIE 573 Engin. Windpower Systems MIE 597B Mechanical Behavior

  15. Lung and alveolar wall elastic and hysteretic behavior in rats: effects of in vivo elastase treatment

    E-Print Network [OSTI]

    Alencar, Adriano Mesquita

    Lung and alveolar wall elastic and hysteretic behavior in rats: effects of in vivo elastase P. Ingenito, and Be´la Suki. Lung and alveolar wall elastic and hysteretic behavior in rats: effects behavior of the alveolar walls and the macroscopic mechanical properties of the whole lung in an in vivo

  16. Defect production during ion implantation of various A/sub III/B/sub V/ semiconductors

    SciTech Connect (OSTI)

    Wesch, W.; Wendler, E.; Goetz, G.; Kekelidse, N.P.

    1989-01-15

    The present paper gives a survey about the defect generation caused by ion implantation of GaAs, InAs, GaP, and InP. By combining Rutherford backscattering spectrometry, optical spectroscopy, and transmission electron microscopic methods, further information concerning the kinetics of the defect production as well as the type of defects created is obtained. Generally, the defect concentration in the region of implantation parameters investigated can be described by the energy density deposited into nuclear processes. Below critical values of the nuclear deposited energy density in GaAs weakly damaged layers containing point defects and point defect clusters are produced. With increasing nuclear deposited energy density an increasing number of amorphous zones is created due to manifold overlap of the initial defect clusters. The results indicate that in GaAs and InAs already at relatively low implantation temperatures, the amorphization occurs via homogeneous defect nucleation. The results obtained for GaP and InP, on the other hand, point at a remarkable contribution of heterogeneous defect nucleation already at room temperature, leading to amorphization at markedly lower nuclear deposited energy densities in spite of nearly identical values of the nuclear deposited energy. It is therefore concluded that defect recombination and annealing at room temperature is much less pronounced in the phosphides than in the arsenides.

  17. Deformation behavior and dislocation mechanisms in TiAl alloys

    SciTech Connect (OSTI)

    Sriram, S.; Vasudevan, V.K. [Univ. of Cincinnati, OH (United States). Dept. of Materials Science and Engineering; Dimiduk, D.M. [Wright Lab., Wright-Patterson AFB, OH (United States)

    1995-08-01

    Polycrystalline Ti-50 and Ti-52Al (in at.%) alloys, with large grain sizes (50Al-300{mu}m, 52Al-500{mu}m) and containing low ({approximately}250 wt.ppm) levels of oxygen were deformed under compression over a wide temperature range (77--1,173 K). The 0.2% proof stress-temperature profiles comprise of three distinct regimes: Regime 1 (between 77--{approximately}600 K), regime 2 (between {approximately}600--1,073 K), and regime 3 (above 1,073 K). Deformation temperature influences the types of dislocations present, the nature of superdislocation dissociations, and the morphological characteristics of both ordinary and super dislocations. Collectively, experiment and theory suggest that the flow properties at low temperatures (regime 1) are controlled by lattice friction, whereas at higher temperatures (regime 2) the properties are dislocation obstacle controlled.

  18. Molecular mechanisms underlying sexual differentiation of the brain and behavior

    E-Print Network [OSTI]

    Ngun, Tuck Cheong

    2012-01-01

    Gorski, Evidence that the hypothalamus is responsible forof the human anterior hypothalamus: an investigation ofof the human anterior hypothalamus: an investigation of

  19. Thermo-mechanical Behavior of Lithium-ion Battery Electrodes 

    E-Print Network [OSTI]

    An, Kai

    2013-11-25

    Developing electric vehicles is widely considered as a direct approach to resolve the energy and environmental challenges faced by the human race. As one of the most promising power solutions to electric cars, the lithium ion battery is expected...

  20. Actin Filament Branching and Behavior under Mechanical Constraints

    E-Print Network [OSTI]

    Risca, Viviana Ioana

    2012-01-01

    reveals three-dimensional filament organization in the actindeformation of actin filaments caused by a mismatchedFigure 7. Forces on actin filaments impinging on a load.

  1. Neurotoxic mechanisms of methylmercury: cellular and behavior changes 

    E-Print Network [OSTI]

    Bellum, Sairam

    2007-04-25

    episodes was cerebellar ataxia. Recent in vitro studies using cultured granule cells showed that MeHg alters intracellular calcium ion ([Ca2+]i) homeostasis, potentiates reactive oxygen species (ROS) generation and loss of mitochondrial membrane potential...

  2. The normal basilar artery: structural properties and mechanical behavior 

    E-Print Network [OSTI]

    Wicker, Bethany Kay

    2009-05-15

    The leading cause of death in patients who survive subarachnoid hemorrhage (SAH) is stroke as a result of cerebral arterial vasospasm1. Such vasospasms involve a vasoactive response, but they remain enigmatic and no clinical ...

  3. Behavioral/Systems/Cognitive Gain Mechanisms for Contextually Guided

    E-Print Network [OSTI]

    Andersen, Richard

    Institute of Technology, Pasadena, California 91125, and 2Bernstein Center for Computational Neuroscience it or rolling it, all de- pending on the rules of a game. Sensorimotor processing streams (Kalaska, 1996; Wise identical sensory conditions (Pet- rides, 1982; Platt and Glimcher, 1999; Wallis and Miller, 2003; Pasupathy

  4. Comments on: 2015 VIII MECHANICAL BEHAVIOR OF SALT

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D BGene NetworkNuclearDNP Post-Doctoral Position inDepartment

  5. Characterization of Thermo-Mechanical Behaviors of Advanced High Strength

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum Based Fuels|Programs | DepartmentDepartmentChallengeSuccess Stories

  6. Thermal-hydrologic-mechanical behavior of single fractures in EGS

    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.Theory of rare Kaon and Pion decays Citation DetailsSciTech(Technical Report)

  7. Thermal-hydrologic-mechanical behavior of single fractures in EGS

    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.Theory of rare Kaon and Pion decays Citation DetailsSciTech(Technical

  8. Sandia Energy - 2015 VIII MECHANICAL BEHAVIOR OF SALT

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation of Fe(II) byMultidayAlumni >Scientific andInstitute Results Pave theVIII

  9. IEEE INFOCOM 2001 Behavior of TCP-like elastic traffic at a buffered

    E-Print Network [OSTI]

    Schwefel, Hans-Peter

    IEEE INFOCOM 2001 Behavior of TCP-like elastic traffic at a buffered bottleneck router Hans by a stochastic process. The essential behavior of TCP-like flow-control mechanisms is captured in the analytic to existing congestion, the throttling mechanism is only activated when the buffer-occupancy at the bottleneck

  10. Blade reliability collaborative : collection of defect, damage and repair data.

    SciTech Connect (OSTI)

    Ashwill, Thomas D.; Ogilvie, Alistair B.; Paquette, Joshua A.

    2013-04-01

    The Blade Reliability Collaborative (BRC) was started by the Wind Energy Technologies Department of Sandia National Laboratories and DOE in 2010 with the goal of gaining insight into planned and unplanned O&M issues associated with wind turbine blades. A significant part of BRC is the Blade Defect, Damage and Repair Survey task, which will gather data from blade manufacturers, service companies, operators and prior studies to determine details about the largest sources of blade unreliability. This report summarizes the initial findings from this work.

  11. Highly defective oxides as sinter resistant thermal barrier coating

    DOE Patents [OSTI]

    Subramanian, Ramesh

    2005-08-16

    A thermal barrier coating material formed of a highly defective cubic matrix structure having a concentration of a stabilizer sufficiently high that the oxygen vacancies created by the stabilizer interact within the matrix to form multi-vacancies, thereby improving the sintering resistance of the material. The concentration of stabilizer within the cubic matrix structure is greater than that concentration of stabilizer necessary to give the matrix a peak ionic conductivity value. The concentration of stabilizer may be at least 30 wt. %. Embodiments include a cubic matrix of zirconia stabilized by at least 30-50 wt. % yttria, and a cubic matrix of hafnia stabilized by at least 30-50 wt. % gadolinia.

  12. Large effect of polydispersity on defect concentrations in colloidal crystals

    E-Print Network [OSTI]

    Sander Pronk; Daan Frenkel

    2004-02-03

    We compute the equilibrium concentration of stacking faults and point defects in polydisperse hard-sphere crystals. We find that, while the concentration of stacking faults remains similar to that of monodisperse hard sphere crystals, the concentration of vacancies decreases by about a factor two. Most strikingly, the concentration of interstitials in the maximally polydisperse crystal may be some six orders of magnitude larger than in a monodisperse crystal. We show that this dramatic increase in interstitial concentration is due to the increased probability of finding small particles and that the small-particle tail of the particle size distribution is crucial for the interstitial concentration in a colloidal crystal.

  13. Sandia Energy - Research Challenge 4: Defect-Carrier Interactions

    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 of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid youOxygenLaboratory Fellows JerryPredictive4: Defect-Carrier

  14. Center for Defect Physics in Structural Materials - CDP

    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 of NaturalDukeWakefieldSulfateSciTechtail.Theory of rare Kaonforsupernovae modelsearch this siteSearchACenter for Defect

  15. Obtaining Reliable Feedback for Sanctioning Reputation Mechanisms

    E-Print Network [OSTI]

    Faltings, B; 10.1613/jair.2243

    2011-01-01

    Reputation mechanisms offer an effective alternative to verification authorities for building trust in electronic markets with moral hazard. Future clients guide their business decisions by considering the feedback from past transactions; if truthfully exposed, cheating behavior is sanctioned and thus becomes irrational. It therefore becomes important to ensure that rational clients have the right incentives to report honestly. As an alternative to side-payment schemes that explicitly reward truthful reports, we show that honesty can emerge as a rational behavior when clients have a repeated presence in the market. To this end we describe a mechanism that supports an equilibrium where truthful feedback is obtained. Then we characterize the set of pareto-optimal equilibria of the mechanism, and derive an upper bound on the percentage of false reports that can be recorded by the mechanism. An important role in the existence of this bound is played by the fact that rational clients can establish a reputation for...

  16. The cellular mechanisms of learning in Aplysia: Of blind men and elephants

    E-Print Network [OSTI]

    Glanzman, David L

    2006-01-01

    postsynaptic mechanisms in a cellular analog of classical4019. Byrne, J. H. 1987. Cellular analysis of associativecorrelation of behavioral and cellular processes. Science

  17. Defective graphene as promising anode material for Na-ion battery and Ca-ion battery

    E-Print Network [OSTI]

    Datta, Dibakar; Shenoy, Vivek B

    2013-01-01

    We have investigated adsorption of Na and Ca on graphene with divacancy (DV) and Stone-Wales (SW) defect. Our results show that adsorption is not possible on pristine graphene. However, their adsorption on defective sheet is energetically favorable. The enhanced adsorption can be attributed to the increased charge transfer between adatoms and underlying defective sheet. With the increase in defect density until certain possible limit, maximum percentage of adsorption also increases giving higher battery capacity. For maximum possible DV defect, we can achieve maximum capacity of 1459 mAh/g for Na-ion batteries (NIBs) and 2900 mAh/g for Ca-ion batteries (CIBs). For graphene full of SW defect, we find the maximum capacity of NIBs and CIBs is around 1071 mAh/g and 2142 mAh/g respectively. Our results will help create better anode materials with much higher capacity and better cycling performance for NIBs and CIBs.

  18. Nematic ordering of topological defects in active liquid crystals

    E-Print Network [OSTI]

    Anand U. Oza; Jörn Dunkel

    2015-07-15

    Identifying the ordering principles of intracellular matter is key to understanding the physics of microbiological systems. Recent experiments show that ATP-driven microtubule-kinesin bundles can form non-equilibrium networks of liquid-crystalline order when trapped in an oil-water interface near a solid boundary. At high densities, the bundles realize a 2D active nematic phase characterized by spontaneous creation and annihilation of topological defects, reminiscent of particle-pair production processes in quantum systems. This remarkable discovery sparked considerable theoretical interest, yet a satisfactory mathematical description has remained elusive, primarily for the following two reasons. First, prevailing multi-component theories feature a large number of unknown parameters that make quantitative comparison with experiment infeasible. Second, the currently favored hydrodynamic models assume divergence-free 2D interfacial flow, thereby promoting turbulent pattern formation through upward cascades. Such cascades are unlikely to occur in experiments, where interface and bulk fluid can continuously exchange matter. Here, we propose a compact alternative continuum theory for dense active liquid crystals by merging ideas from the Landau-de Gennes and Swift-Hohenberg theories. The resulting fourth-order model agrees quantitatively with experimental data, correctly predicts a regime of long-range nematic alignment of defects, and manifests an analogy with a generalized Gross-Pitaevskii quantum theory. Generally, our results suggest that universal ordering principles may govern a wide range of active materials.

  19. Defect structure of ultrafine MgB{sub 2} nanoparticles

    SciTech Connect (OSTI)

    Bateni, Ali; Somer, Mehmet E-mail: msomer@ku.edu.tr; Repp, Sergej; Erdem, Emre E-mail: msomer@ku.edu.tr; Thomann, Ralf; Acar, Selçuk

    2014-11-17

    Defect structure of MgB{sub 2} bulk and ultrafine particles, synthesized by solid state reaction route, have been investigated mainly by the aid of X-band electron paramagnetic resonance spectrometer. Two different amorphous Boron (B) precursors were used for the synthesis of MgB{sub 2}, namely, boron 95 (purity 95%–97%, <1.5??m) and nanoboron (purity >98.5%, <250?nm), which revealed bulk and nanosized MgB{sub 2}, respectively. Scanning and transmission electron microscopy analysis demonstrate uniform and ultrafine morphology for nanosized MgB{sub 2} in comparison with bulk MgB{sub 2}. Powder X-ray diffraction data show that the concentration of the by-product MgO is significantly reduced when nanoboron is employed as precursor. It is observed that a significant average particle size reduction for MgB{sub 2} can be achieved only by using B particles of micron or nano size. The origin and the role of defect centers were also investigated and the results proved that at nanoscale MgB{sub 2} material contains Mg vacancies. Such vacancies influence the connectivity and the conductivity properties which are crucial for the superconductivity applications.

  20. Subsurface Defect Detection in Metals with Pulsed Eddy Current

    SciTech Connect (OSTI)

    Plotnikov, Yuri A. [GE Global Research Center, One Research Circle, Niskayuna, NY 12309-1135 (United States); Bantz, Walter J. [GE Aircraft Engines M and QTD, 10270 St. Rita Lane, Cincinnati, OH 45215 (United States)

    2005-04-09

    The eddy current (EC) method is traditionally used for open surface crack detection in metallic components. Subsurface voids in bulk metals can also be detected by the eddy current devices. Taking into consideration the skin effect in conductive materials, a lower frequency of electromagnetic excitation is used for a deeper penetration. A set of special specimens was designed and fabricated to investigate sensitivity to subsurface voids. Typically, flat bottom holes (FBHs) are used for subsurface defect simulation. This approach is not very representative of real defects for eddy current inspection because the FBH depth extends to the bottom of the specimen. Two-layer specimens with finite depth FBHs were fabricated and scanned with conventional EC of variable frequency. Sensitivity and spatial resolution of EC diminish with flaw depth. The pulsed EC approach was applied for flaw detection at variable distance under the surface. The transient response from multi-layer model was derived and compared to experiments. The multi-frequency nature of pulsed excitation provides effective coverage of a thick layer of material in one pass. Challenging aspects of subsurface flaw detection and visualization using the EC technique are discussed.

  1. Chiral asymmetry in propagation of soliton defects in crystalline backgrounds

    E-Print Network [OSTI]

    Adrian Arancibia; Mikhail S. Plyushchay

    2015-08-03

    By applying Darboux-Crum transformations to the Lax pair formulation of the Korteweg-de Vries (KdV) equation, we construct new sets of multi-soliton solutions to it as well as to the modified Korteweg-de Vries (mKdV) equation. The obtained solutions exhibit a chiral asymmetry in propagation of different types defects in crystalline backgrounds. We show that the KdV solitons of pulse and compression modulation types, which support bound states in semi-infinite and finite forbidden bands in the spectrum of the perturbed quantum one-gap Lame system, propagate in opposite directions with respect to the asymptotically periodic background. A similar but more complicated picture also appears for the multi-kink-antikink mKdV solitons that propagate with a privileged direction over topologically trivial or topologically nontrivial crystalline background in dependence on position of energy levels of the trapped bound states in spectral gaps of the associated Dirac system. Exotic N=4 nonlinear supersymmetric structure incorporating Lax-Novikov integrals of a pair of perturbed Lame systems is shown to underlie the Miura-Darboux-Crum construction. It unifies the KdV and mKdV solutions, detects the defects and distinguishes their types, and identifies the types of crystalline backgrounds.

  2. Taming Supersymmetric Defects in 3d-3d Correspondence

    E-Print Network [OSTI]

    Gang, Dongmin; Romo, Mauricio; Yamazaki, Masahito

    2015-01-01

    We study knots in 3d Chern-Simons theory with complex gauge group $SL(N,\\mathbb{C})$, in the context of its relation with 3d $\\mathcal{N}=2$ theory (the so-called 3d-3d correspondence). The defect has either co-dimension 2 or co-dimension 4 inside the 6d $(2,0)$ theory, which is compactified on a 3-manifold $\\hat{M}$. We identify such defects in various corners of the 3d-3d correspondence, namely in 3d $SL(N,\\mathbb{C})$ Chern-Simons theory, in 3d $\\mathcal{N}=2$ theory, in 5d $\\mathcal{N}=2$ super Yang-Mills theory, and in the M-theory holographic dual. We can make quantitative checks of the 3d-3d correspondence by computing partition functions at each of these theories. This Letter is a companion to a longer paper, which contains more details and more results.

  3. S9 -Kinetics & Mechanism of Metal Sorption/Release on Natural Materials ADSORPTION MECHANISMS OF PB ON AMORPHOUS SILICA: AN XAS

    E-Print Network [OSTI]

    Sparks, Donald L.

    S9 - Kinetics & Mechanism of Metal Sorption/Release on Natural Materials ADSORPTION MECHANISMS metals in soil and aquatic systems, fundamental knowledge of the mechanisms involved in the adsorption the sorption behavior and mechanisms of Pb on amorphous silica using X-ray absorption spectroscopy (XAS

  4. 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

  5. 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

  6. 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...

  7. Essays in Behavioral Finance

    E-Print Network [OSTI]

    Huang, Xing

    2013-01-01

    behavior. Journal of Finance 64(6), 2515–2534. Cohen, L. ,returns. Journal of Finance 63(4), 1977–2011. Cohen, L. andannouncements. Journal of Finance 64, 709–749. DeLong, J.

  8. Diffusion Coefficients in a Lamellar Lyotropic Phase: Evidence for Defects Connecting the Surfactant Structure

    E-Print Network [OSTI]

    Doru Constantin; Patrick Oswald

    2015-04-09

    We measure diffusion coefficients in the lamellar phase of the nonionic binary system C$_{12}$EO$_6$/H$_2$O using fluorescence recovery after photobleaching. The diffusion coefficient across the lamellae shows an abrupt increase upon approaching the lamellar-isotropic phase transition. We interpret this feature in terms of defects connecting the surfactant structure. An estimation of the defect density and of the variation in defect energy close to the transition is given in terms of a simple model.

  9. 2.001 Mechanics & Materials I, Spring 2003

    E-Print Network [OSTI]

    Sarma, Sanjay E.

    Introduction to statics and the mechanics of deformable solids. Emphasis on the three basic principles of equilibrium, geometric compatibility, and material behavior. Stress and its relation to force and moment; strain and ...

  10. Mechanical compression drives cancer cells toward invasive phenotype

    E-Print Network [OSTI]

    Tse, Janet M.

    Uncontrolled growth in a confined space generates mechanical compressive stress within tumors, but little is known about how such stress affects tumor cell behavior. Here we show that compressive stress stimulates migration ...

  11. Mechanics of deformation of carbon nanotube-polymer nanocomposites

    E-Print Network [OSTI]

    Akiskalos, Theodoros, 1978-

    2004-01-01

    The goal is to develop finite element techniques to evaluate the mechanical behavior of carbon nanotube enabled composites and gain a thorough understanding of the parameters that affect the properties of the composite, ...

  12. Aquifer behavior with reinjection 

    E-Print Network [OSTI]

    Bonet, Euclides Jose

    1967-01-01

    AQUIFER BEHAVIOR WITH REINJECTION A Thesis By EUCLIDES JOSE BONET Submitted to the Graduate College of the Texas ARUM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May, f967 Major Subject... Petroleum Engineering AQUIFER BEHAVIOR WITH REINJECTION A Thesis By E UC LI DES JOSE BONE T Approved as to style and content by: (Chairman of Committee) (Member) (Member) May, 1967 ACKNOWLEDGMENT Thanks are due to Petroleo Brasilerio S...

  13. 2012 DEFECTS IN SEMICONDUCTORS GORDON RESEARCH CONFERENCE, AUGUST 12-17, 2012

    SciTech Connect (OSTI)

    GLASER, EVAN

    2012-08-17

    The meeting shall strive to develop and further the fundamental understanding of defects and their roles in the structural, electronic, optical, and magnetic properties of bulk, thin film, and nanoscale semiconductors and device structures. Point and extended defects will be addressed in a broad range of electronic materials of particular current interest, including wide bandgap semiconductors, metal-oxides, carbon-based semiconductors (e.g., diamond, graphene, etc.), organic semiconductors, photovoltaic/solar cell materials, and others of similar interest. This interest includes novel defect detection/imaging techniques and advanced defect computational methods.

  14. A transmission matrix for a fused pair of integrable defects in the sine-Gordon model

    E-Print Network [OSTI]

    E. Corrigan; C. Zambon

    2010-06-04

    Within the quantum sine-Gordon model a transmission matrix describing the scattering of a soliton with a fused pair of integrable defects is proposed. The result is consistent with the classical picture of scattering and highlights the differences between two defects located at separated points and two defects fused at the same point. Moreover, the analysis reveals how, for certain choices of parameters, both the soliton-soliton and the lightest-breather-soliton S-matrices of the sine-Gordon model are embedded within the transmission matrix, supporting an interpretation in which defects may be regarded as soliton constituents.

  15. American Institute of Aeronautics and Astronautics Effects of Defects: Part A -Development of a Protocol for

    E-Print Network [OSTI]

    American Institute of Aeronautics and Astronautics 1 Effects of Defects: Part A - Development;American Institute of Aeronautics and Astronautics 2 Introduction he size, weight, shape and economic

  16. Behavior Based Energy Efficiency (BBEE)

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

    Behavior Based Energy Efficiency Program Profiles 2011 Bonneville Power Administration Residential Behavior Based Energy Efficiency Program Profiles 2011 Prepared by Skip Schick...

  17. Modeling the mechanical response of PBX 9501

    SciTech Connect (OSTI)

    Ragaswamy, Partha; Lewis, Matthew W; Liu, Cheng; Thompson, Darla G

    2010-01-01

    An engineering overview of the mechanical response of Plastic-Bonded eXplosives (PBXs), specifically PBX 9501, will be provided with emphasis on observed mechanisms associated with different types of mechanical testing. Mechanical tests in the form of uniaxial tension, compression, cyclic loading, creep (compression and tension), and Hopkinson bar show strain rate and temperature dependence. A range of mechanical behavior is observed which includes small strain recoverable response in the form of viscoelasticity; change in stiffness and softening beyond peak strength due to damage in the form microcracks, debonding, void formation and the growth of existing voids; inelastic response in the form of irrecoverable strain as shown in cyclic tests, and viscoelastic creep combined with plastic response as demonstrated in creep and recovery tests. The main focus of this paper is to elucidate the challenges and issues involved in modeling the mechanical behavior of PBXs for simulating thermo-mechanical responses in engineering components. Examples of validation of a constitutive material model based on a few of the observed mechanisms will be demonstrated against three point bending, split Hopkinson pressure bar and Brazilian disk geometry.

  18. Research and Application on the Mechanical Characters of Rotary Steering Drilling Tool 

    E-Print Network [OSTI]

    Jiang, Shan

    2014-12-10

    and downhole accidents with more exposed reservoirs, it delivers excellent performance. A basic theoretical study of a rotary steering tool system helps us further master the mechanical characteristics of the tool system from the angle of mechanical behavior...

  19. Modeling and implementation of solder-activated joints for single actuator, centimeter-scale robotic mechanisms

    E-Print Network [OSTI]

    Telleria, Maria J

    2010-01-01

    This thesis explains when, and why, solder-based phase change materials (PCMs) are best-suited as a means to modify a robotic mechanism's kinematic and elastomechanic behavior. The preceding refers to mechanisms that possess ...

  20. 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

  1. 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

  2. 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

  3. Towards the topological quantization of classical mechanics

    E-Print Network [OSTI]

    Francisco Nettel; Hernando Quevedo; Moices Rodriguez

    2008-01-16

    We consider the method of topological quantization for conservative systems with a finite number of degrees of freedom. Maupertuis' formalism for classical mechanics provides an appropriate scenario which permit us to adapt the method of topological quantization, originally formulated for gravitational field configurations. We show that any conservative system in classical mechanics can be associated with a principal fiber bundle. As an application of topological quantization we derive expressions for the topological spectra of some simple mechanical systems and show that they reproduce the discrete behavior of the corresponding canonical spectra.

  4. Atomic-scale investigation of point defects and hydrogen-solute atmospheres on the edge dislocation mobility in alpha iron

    SciTech Connect (OSTI)

    Bhatia, M. A.; Solanki, K. N.; Groh, S.

    2014-08-14

    In this study, we present atomistic mechanisms of 1/2 [111](11{sup ¯}0) edge dislocation interactions with point defects (hydrogen and vacancies) and hydrogen solute atmospheres in body centered cubic (bcc) iron. In metals such as iron, increases in hydrogen concentration can increase dislocation mobility and/or cleavage-type decohesion. Here, we first investigate the dislocation mobility in the presence of various point defects, i.e., change in the frictional stress as the edge dislocation interacts with (a) vacancy, (b) substitutional hydrogen, (c) one substitutional and one interstitial hydrogen, (d) interstitial hydrogen, (e) vacancy and interstitial hydrogen, and (f) two interstitial hydrogen. Second, we examine the role of a hydrogen-solute atmosphere on the rate of local dislocation velocity. The edge dislocation simulation with a vacancy in the compression side of the dislocation and an interstitial hydrogen atom at the tension side exhibit the strongest mechanical response, suggesting a higher potential barrier and hence, the higher frictional stress (i.e., ?83% higher than the pure iron Peierls stress). In the case of a dislocation interacting with a vacancy on the compressive side, the vacancy binds with the edge dislocation, resulting in an increase in the friction stress of about 28% when compared with the Peierls stress of an edge dislocation in pure iron. Furthermore, as the applied strain increases, the vacancy migrates through a dislocation transportation mechanism by attaining a velocity of the same order as the dislocation velocity. For the case of the edge dislocation interacting with interstitial hydrogen on the tension side, the hydrogen atom jumps through one layer perpendicular to the glide plane during the pinning-unpinning process. Finally, our simulation of dislocation interactions with hydrogen show first an increase in the local dislocation velocity followed by a pinning of the dislocation core in the atmosphere, resulting in resistance to dislocation motion as the dislocation moves though the hydrogen-solute atmospheres. With this systematic, atomistic study of the edge dislocation with various point defects, we show significant increase in obstacle strengths in addition to an increase in the local dislocation velocity during interaction with solute atmospheres. The results have implications for constitutive development and modeling of the hydrogen effect on dislocation mobility and deformation in metals.

  5. Nematic ordering of topological defects in active liquid crystals

    E-Print Network [OSTI]

    Oza, Anand U

    2015-01-01

    Identifying the ordering principles of intracellular matter is key to understanding the physics of microbiological systems. Recent experiments show that ATP-driven microtubule-kinesin bundles can form non-equilibrium networks of liquid-crystalline order when trapped in an oil-water interface near a solid boundary. At high densities, the bundles realize a 2D active nematic phase characterized by spontaneous creation and annihilation of topological defects, reminiscent of particle-pair production processes in quantum systems. This remarkable discovery sparked considerable theoretical interest, yet a satisfactory mathematical description has remained elusive, primarily for the following two reasons. First, prevailing multi-component theories feature a large number of unknown parameters that make quantitative comparison with experiment infeasible. Second, the currently favored hydrodynamic models assume divergence-free 2D interfacial flow, thereby promoting turbulent pattern formation through upward cascades. Suc...

  6. Electrodes mitigating effects of defects in organic electronic devices

    DOE Patents [OSTI]

    Heller, Christian Maria Anton (Albany, NY)

    2008-05-06

    A compound electrode for organic electronic devices comprises a thin first layer of a first electrically conducting material and a second electrically conducting material disposed on the first layer. In one embodiment, the second electrically conducting material is formed into a plurality of elongated members. In another embodiment, the second material is formed into a second layer. The elongated members or the second layer has a thickness greater than that of the first layer. The second layer is separated from the first layer by a conducting material having conductivity less than at least the material of the first layer. The compound electrode is capable of mitigating adverse effects of defects, such as short circuits, in the construction of the organic electronic devices, and can be included in light-emitting or photovoltaic devices.

  7. Periodic Schrödinger operators with local defects and spectral pollution

    E-Print Network [OSTI]

    Eric Cancès; Virginie Ehrlacher; Yvon Maday

    2011-11-16

    This article deals with the numerical calculation of eigenvalues of perturbed periodic Schr\\"odinger operators located in spectral gaps. Such operators are encountered in the modeling of the electronic structure of crystals with local defects, and of photonic crystals. The usual finite element Galerkin approximation is known to give rise to spectral pollution. In this article, we give a precise description of the corresponding spurious states. We then prove that the supercell model does not produce spectral pollution. Lastly, we extend results by Lewin and S\\'er\\'e on some no-pollution criteria. In particular, we prove that using approximate spectral projectors enables one to eliminate spectral pollution in a given spectral gap of the reference periodic Sch\\"odinger operator.

  8. Nonlocal competition and logistic growth: patterns, defects and fronts

    E-Print Network [OSTI]

    Yosef E. Maruvka; Nadav M. Shnerb

    2005-06-22

    Logistic growth of diffusing reactants on spatial domains with long range competition is studied. The bifurcations cascade involved in the transition from the homogenous state to a spatially modulated stable solution is presented, and a distinction is made between a modulated phase, dominated by single or few wavenumbers, and the spiky phase, where localized colonies are separated by depleted region. The characteristic defects in the periodic structure are presented for each phase, together with the invasion dynamics in case of local initiation. It is shown that the basic length scale that controls the bifurcation is the width of the Fisher front, and that the total population grows as this width decreases. A mix of analytic results and extensive numerical simulations yields a comprehensive examination of the possible phases for logistic growth in the presence of nonlocal competition.

  9. Ion beam collimating grid to reduce added defects

    DOE Patents [OSTI]

    Lindquist, Walter B. (Oakland, CA); Kearney, Patrick A. (Livermore, CA)

    2003-01-01

    A collimating grid for an ion source located after the exit grid. The collimating grid collimates the ion beamlets and disallows beam spread and limits the beam divergence during transients and steady state operation. The additional exit or collimating grid prevents beam divergence during turn-on and turn-off and prevents ions from hitting the periphery of the target where there is re-deposited material or from missing the target and hitting the wall of the vessel where there is deposited material, thereby preventing defects from being deposited on a substrate to be coated. Thus, the addition of a collimating grid to an ion source ensures that the ion beam will hit and be confined to a specific target area.

  10. Defect localization, characterization and reliability assessment in emerging photovoltaic devices.

    SciTech Connect (OSTI)

    Yang, Benjamin Bing-Yeh; Cruz-Campa, Jose Luis; Haase, Gad S.; Tangyunyong, Paiboon; Cole, Edward Isaac,; Okandan, Murat; Nielson, Gregory N.

    2014-04-01

    Microsystems-enabled photovoltaics (MEPV) can potentially meet increasing demands for light-weight, portable, photovoltaic solutions with high power density and efficiency. The study in this report examines failure analysis techniques to perform defect localization and evaluate MEPV modules. CMOS failure analysis techniques, including electroluminescence, light-induced voltage alteration, thermally-induced voltage alteration, optical beam induced current, and Seabeck effect imaging were successfully adapted to characterize MEPV modules. The relative advantages of each approach are reported. In addition, the effects of exposure to reverse bias and light stress are explored. MEPV was found to have good resistance to both kinds of stressors. The results form a basis for further development of failure analysis techniques for MEPVs of different materials systems or multijunction MEPVs. The incorporation of additional stress factors could be used to develop a reliability model to generate lifetime predictions for MEPVs as well as uncover opportunities for future design improvements.

  11. Yield improvement and defect reduction in steel casting

    SciTech Connect (OSTI)

    Kent Carlson

    2004-03-16

    This research project investigated yield improvement and defect reduction techniques in steel casting. Research and technology development was performed in the following three specific areas: (1) Feeding rules for high alloy steel castings; (2) Unconventional yield improvement and defect reduction techniques--(a) Riser pressurization; and (b) Filling with a tilting mold; and (3) Modeling of reoxidation inclusions during filling of steel castings. During the preparation of the proposal for this project, these areas were identified by the High Alloy Committee and Carbon and Low Alloy Committee of the Steel Founders' Society of America (SFSA) as having the highest research priority to the steel foundry industry. The research in each of the areas involved a combination of foundry experiments, modeling and simulation. Numerous SFSA member steel foundries participated in the project through casting trials and meetings. The technology resulting from this project will result in decreased scrap and rework, casting yield improvement, and higher quality steel castings produced with less iteration. This will result in considerable business benefits to steel foundries, primarily due to reduced energy and labor costs, increased capacity and productivity, reduced lead-time, and wider use and application of steel castings. As estimated using energy data provided by the DOE, the technology produced as a result of this project will result in an energy savings of 2.6 x 10{sup 12} BTU/year. This excludes the savings that were anticipated from the mold tilting research. In addition to the energy savings, and corresponding financial savings this implies, there are substantial environmental benefits as well. The results from each of the research areas listed above are summarized.

  12. Mechanics and tribology of MEMS materials.

    SciTech Connect (OSTI)

    Prasad, Somuri V.; Dugger, Michael Thomas; Boyce, Brad Lee; Buchheit, Thomas Edward

    2004-04-01

    Micromachines have the potential to significantly impact future weapon component designs as well as other defense, industrial, and consumer product applications. For both electroplated (LIGA) and surface micromachined (SMM) structural elements, the influence of processing on structure, and the resultant effects on material properties are not well understood. The behavior of dynamic interfaces in present as-fabricated microsystem materials is inadequate for most applications and the fundamental relationships between processing conditions and tribological behavior in these systems are not clearly defined. We intend to develop a basic understanding of deformation, fracture, and surface interactions responsible for friction and wear of microelectromechanical system (MEMS) materials. This will enable needed design flexibility for these devices, as well as strengthen our understanding of material behavior at the nanoscale. The goal of this project is to develop new capabilities for sub-microscale mechanical and tribological measurements, and to exercise these capabilities to investigate material behavior at this size scale.

  13. ASCE Specialty Conference on Probabilistic Mechanics and Structural Reliability Bhattacharya, B. and Lu, Q.

    E-Print Network [OSTI]

    Bhattacharya, Baidurya

    . This paper studies the effects of randomly distributed Stone-Wales (SW or 5-7- 7-5) defects on the mechanical to be among the most robust materials: it has high elastic modulus (order of 1 TPa), high strength (up to 150 GPa), good ductility (up to 15% max strain), flexibility to bending and buckling and robustness under

  14. Using Simulation for Assessing the Real Impact of Test Coverage on Defect Lionel C. Briand

    E-Print Network [OSTI]

    Carleton University

    AT acceptance test IT integration test UT unit test Notation dc defect coverage tc test coverage ti test coverage measures) Test coverage is measured as the percentage of constructs - as defined by the coverageUsing Simulation for Assessing the Real Impact of Test Coverage on Defect Coverage Lionel C. Briand

  15. Using Explicit and Machine-Understandable Engineering Knowledge for Defect Detection in Automation Systems Engineering

    E-Print Network [OSTI]

    industrial complexes are very high. Traditional approaches for defect detection in automation systems and data models which are used within the engineering of industrial automation systems. Thus, some defects Nowadays, industrial automation systems have tendencies to become more and more complex and large

  16. Radiation Effects & Defects in Solids Vol. 164, No. 10, October 2009, 585591

    E-Print Network [OSTI]

    Pandey, Ravi

    and oxygen impurity in AlN: spintronic quantum dots J.M. Vaila,b *, T. Haroonc , J. Hernandez-Melgara,b , D) Point defects with non-zero spin are prototypical spintronic quantum dots. Here two anion-site defects and local mode force constants. The relevance to spintronic quantum dots in semiconductors is discussed

  17. Electrochemical method for defect delineation in silicon-on-insulator wafers

    DOE Patents [OSTI]

    Guilinger, Terry R. (Albuquerque, NM); Jones, Howland D. T. (Albuquerque, NM); Kelly, Michael J. (Albuquerque, NM); Medernach, John W. (Albuquerque, NM); Stevenson, Joel O. (Albuquerque, NM); Tsao, Sylvia S. (Albuquerque, NM)

    1991-01-01

    An electrochemical method for defect delineation in thin-film SOI or SOS wafers in which a surface of a silicon wafer is electrically connected so as to control the voltage of the surface within a specified range, the silicon wafer is then contacted with an electrolyte, and, after removing the electrolyte, defects and metal contamination in the silicon wafer are identified.

  18. The Role of Silicon Interstitials in the Formation of Boron-Oxygen Defects in Crystalline Silicon

    E-Print Network [OSTI]

    The Role of Silicon Interstitials in the Formation of Boron-Oxygen Defects in Crystalline Silicon@ise.fhg.de Keywords: crystalline silicon, Czochralski, boron-oxygen defect, silicon interstitial Abstract. Oxygen-rich crystalline silicon materials doped with boron are plagued by the presence of a well-known carrier

  19. Defect controlled transverse compressive strength of polyethylene fiber M.R. O'Masta a,

    E-Print Network [OSTI]

    Wadley, Haydn

    Defect controlled transverse compressive strength of polyethylene fiber laminates M.R. O'Masta a: Laminate defects Voids Compressive strength Polyethylene composites a b s t r a c t Using a combination weight polyethylene (UHMWPE) fibers and thermoplastic resins, and investi- gated their effects upon

  20. Production of defects in hexagonal boron nitride monolayer under ion irradiation O. Lehtinen a,

    E-Print Network [OSTI]

    Krasheninnikov, Arkady V.

    Production of defects in hexagonal boron nitride monolayer under ion irradiation O. Lehtinen a, , E: Hexagonal boron nitride monolayer Ion irradiation Defect a b s t r a c t Atomistic computer simulations monolayer to irradiation with noble gas ions having energies from 35 eV up to 10 MeV. Probabilities

  1. Understanding structural defects in lithium-rich layered oxide cathodes Karalee A. Jarvis,a

    E-Print Network [OSTI]

    Ferreira, Paulo J.

    the required amounts of lithium, manganese, and nickel acetates were added to this solution. The molar ratioUnderstanding structural defects in lithium-rich layered oxide cathodes Karalee A. Jarvis, Accepted 31st March 2012 DOI: 10.1039/c2jm30575e Planar defects in lithium-rich layered oxides were

  2. Hydrogen-related defects in bulk ZnO Matthew D. McCluskey,1

    E-Print Network [OSTI]

    McCluskey, Matthew

    Hydrogen-related defects in bulk ZnO Matthew D. McCluskey,1 Slade J. Jokela,1 and Marianne C. Tarun. This paper reviews recent work on hydrogen donors and nitrogen-hydrogen complexes in ZnO. INTRODUCTION Zinc be understood. One such defect is hydrogen, a common impurity in ZnO. We have studied hydrogen donors using

  3. Hydrogen interaction with point defects in tungsten K. Heinola, T. Ahlgren, K. Nordlund, and J. Keinonen

    E-Print Network [OSTI]

    Nordlund, Kai

    Hydrogen interaction with point defects in tungsten K. Heinola, T. Ahlgren, K. Nordlund, and J-principles calculations were used in determining the binding and trapping properties of hydrogen to point defects in tungsten. Hydrogen zero-point vibrations were taken into account. It was concluded that the monovacancy can

  4. Faster Defect Resolution with Higher Technical Quality of Software Bart Luijten

    E-Print Network [OSTI]

    Visser, Joost

    Faster Defect Resolution with Higher Technical Quality of Software Bart Luijten Delft University of the relation between technical quality of software products and the defect resolution performance of numerous software products that have been evaluated with the SIG quality model in the context of software

  5. Stone-Wales defects in graphene and other planar sp2 -bonded materials

    E-Print Network [OSTI]

    Alavi, Ali

    that the canonical flat SW defect in graphene is in fact not a local minimum on the potential-energy surface PES have also been predicted to alter the electronic properties band structure and density of states in graphitic materials.12 However, in clean unmodified graphene it is customarily assumed that SW defects

  6. DISSERTATION Role of the Cu-O Defect in CdTe Solar Cells

    E-Print Network [OSTI]

    Sites, James R.

    DISSERTATION Role of the Cu-O Defect in CdTe Solar Cells Submitted by Caroline R. Corwine OF THE CU-O DEFECT COMPLEX IN CDTE SOLAR CELLS Thin-film CdTe is one of the leading materials used in photovoltaic (PV) solar cells. One way to improve device performance and stability is through understanding how

  7. Mesoscopic pointlike defects in semiconductors: Deep-level energies D. D. Nolte

    E-Print Network [OSTI]

    Nolte, David D.

    Mesoscopic pointlike defects in semiconductors: Deep-level energies D. D. Nolte Department in common with quantum dots, such as Coulomb-charging energies, but unlike quantum dots their electronic properties are dominated by the covalent bond energies of the defect-semiconductor interface. The deep

  8. MAGNETIC FLUX LEAKAGE INVESTIGATION OF INTERACTING DEFECTS: COMPETITIVE EFFECTS OF STRESS CONCENTRATION AND MAGNETIC SHIELDING

    E-Print Network [OSTI]

    Clapham, Lynann

    CONCENTRATION AND MAGNETIC SHIELDING C Mandache1,2 and L Clapham1 1 Queen's University, Kingston, Ontario, K7L 3 of their stress concentrations and by the mutual shielding of the defects from the applied flux density. This type and magnetic flux shielding further complicates the defect-induced MFL signal calibration [6]. The focus

  9. Submitted for publication Production of defects in supported carbon nanotubes under ion irradiation

    E-Print Network [OSTI]

    Nordlund, Kai

    Submitted for publication Production of defects in supported carbon nanotubes under ion irradiation University of Helsinki, Finland (December 10, 2001) Ion irradiation of individual carbon nanotubes deposited near irradiation-induced defects. 81.07.De, 61.48+c, 61.80.Jh,73.22.-f I. INTRODUCTION Recent

  10. Stability of irradiation-induced point defects on walls of carbon nanotubes A. V. Krasheninnikova)

    E-Print Network [OSTI]

    Krasheninnikov, Arkady V.

    Stability of irradiation-induced point defects on walls of carbon nanotubes A. V. Krasheninnikova study the structure and stability of atomic-scale irradiation-induced defects on walls of carbon-dose, low-temperature ion irradiation, we model the temporal evolution of single vacancies and vacancy

  11. Defects in articular cartilage metabolism and early arthritis in fibroblast growth factor receptor 3

    E-Print Network [OSTI]

    Buschmann, Michael

    Defects in articular cartilage metabolism and early arthritis in fibroblast growth factor receptor Laboratory, Shriner's Hospital for Children and 3 Centre for Bone and Periodontal Research, McGill University technology for cartilage tissue engineering and assisted repair. Assisted repair of focal defects

  12. Modeling the probability of excitation and the defective part level as testing progresses 

    E-Print Network [OSTI]

    Dworak, Jennifer Lynn

    2000-01-01

    The primary purpose of digital circuit manufacture testing is to detect defective parts so that they will not be sold to customers. Predicting the defective part level, which results after a set of test patterns has been applied, is not a simple...

  13. Defect transition energies and the density of electronic states in hydrogenated amorphous silicon

    E-Print Network [OSTI]

    Tolk, Norman H.

    Defect transition energies and the density of electronic states in hydrogenated amorphous silicon G in hydrogenated amorphous silicon (a-Si:H). These measurements suggest that the density of neutral defects is much of the corresponding transition energies are determined and agree with two models proposed to describe the density

  14. Multichannel framework for singular quantum mechanics

    SciTech Connect (OSTI)

    Camblong, Horacio E.; Epele, Luis N.; Fanchiotti, Huner; García Canal, Carlos A.; Ordóñez, Carlos R.

    2014-01-15

    A multichannel S-matrix framework for singular quantum mechanics (SQM) subsumes the renormalization and self-adjoint extension methods and resolves its boundary-condition ambiguities. In addition to the standard channel accessible to a distant (“asymptotic”) observer, one supplementary channel opens up at each coordinate singularity, where local outgoing and ingoing singularity waves coexist. The channels are linked by a fully unitary S-matrix, which governs all possible scenarios, including cases with an apparent nonunitary behavior as viewed from asymptotic distances. -- Highlights: •A multichannel framework is proposed for singular quantum mechanics and analogues. •The framework unifies several established approaches for singular potentials. •Singular points are treated as new scattering channels. •Nonunitary asymptotic behavior is subsumed in a unitary multichannel S-matrix. •Conformal quantum mechanics and the inverse quartic potential are highlighted.

  15. Relativistic mechanism of superconductivity

    E-Print Network [OSTI]

    H. Y. Cui

    2002-12-17

    According to the theory of relativity, the relativistic Coulomb's force between an electron pair is composed of two parts, the main part is repulsive, while the rest part can be attractive in certain situations. Thus the relativistic attraction of an electron pair provides an insight into the mechanism of superconductivity. In superconductor, there are, probably at least, two kinds of collective motions which can eliminate the repulsion between two electrons and let the attraction being dominant, the first is the combination of lattice and electron gas, accounting for traditional superconductivity; the second is the electron gas themselves, accounting for high $T_c$ superconductivity. In usual materials, there is a good balance between the repulsion and attraction of an electron pair, the electrons are regarded as free electrons so that Fermi gas theory plays very well. But in some materials, when the repulsion dominates electron pairs, the electron gas will has a behavior opposite to superconductivity. In the present paper the superconducting states are discussed in terms of relativistic quantum theory in details, some significant results are obtained including quantized magnetic flux, London equation, Meissner effect and Josephson effect.

  16. Exploration of mechanisms underlying the strain-rate-dependent mechanical property of single chondrocytes

    SciTech Connect (OSTI)

    Nguyen, Trung Dung; Gu, YuanTong, E-mail: yuantong.gu@qut.edu.au [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland (Australia)

    2014-05-05

    Based on the characterization by Atomic Force Microscopy, we report that the mechanical property of single chondrocytes has dependency on the strain-rates. By comparing the mechanical deformation responses and the Young's moduli of living and fixed chondrocytes at four different strain-rates, we explore the deformation mechanisms underlying this dependency property. We found that the strain-rate-dependent mechanical property of living cells is governed by both of the cellular cytoskeleton and the intracellular fluid when the fixed chondrocytes are mainly governed by their intracellular fluid, which is called the consolidation-dependent deformation behavior. Finally, we report that the porohyperelastic constitutive material model which can capture the consolidation-dependent behavior of both living and fixed chondrocytes is a potential candidature to study living cell biomechanics.

  17. Exploring the interaction between lithium ion and defective graphene surface using dispersion corrected DFT studies

    SciTech Connect (OSTI)

    Vijayakumar, M.; Hu, Jian Z.

    2013-10-15

    To analyze the lithium ion interaction with realistic graphene surfaces, we carried out dispersion corrected DFT-D3 studies on graphene with common point defects and chemisorbed oxygen containing functional groups along with defect free graphene surface. Our study reveals that, the interaction between lithium ion (Li+) and graphene is mainly through the delocalized ? electron of pure graphene layer. However, the oxygen containing functional groups pose high adsorption energy for lithium ion due to the Li-O ionic bond formation. Similarly, the point defect groups interact with lithium ion through possible carbon dangling bonds and/or cation-? type interactions. Overall these defect sites render a preferential site for lithium ions compared with pure graphene layer. Based on these findings, the role of graphene surface defects in lithium battery performance were discussed.

  18. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    of the complex structures and behaviors observed in animal models. They guide the development of small robots

  19. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

    SciTech Connect (OSTI)

    Shao, Lin; Wei, C. -C.; Gigax, J.; Aitkaliyeva, A.; Chen, D.; Sencer, B. H.; Garner, F. A.

    2014-06-10

    Ion irradiation has been widely used to simulate radiation damage induced by neutrons. However, there are a number of features of ion-induced damage that differ from neutron-induced damage, and these differences require investigation before behavior arising from neutron bombardment can be confidently predicted from ion data. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. The depth dependence of void swelling was observed not to follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then, during continued irradiation, move to progressively deeper and higher-damage depths. This indicates a strong initial suppression of void nucleation in the peak damage region that continued irradiation eventually overcomes. This phenomenon is shown by the Boltzmann transport equation method to be due to depth-dependent defect imbalances created under ion irradiation. These findings thus demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extracting and interpreting ion-induced swelling data.

  20. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

    SciTech Connect (OSTI)

    Lin Shao; C.-C. Wei; J. Gigax; A. Aitkaliyeva; D. Chen; B.H. Sencer; F.A. Garner

    2014-10-01

    Ion irradiation has been widely used to simulate neutron-induced radiation damage. There are a number of features of ion-induced damage that differ from neutron-induced damage, however, and these differences require investigation before ion data can be confidently used to predict behavior arising from neutron bombardment. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. It was observed that the depth dependence of void swelling does not follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then moves to progressively deeper and higher-damage depths during continued irradiation. This indicates a strong initial suppression of void nucleation in the peak damage region that is eventually overcome with continued irradiation. Using the Boltzmann transport equation method, this phenomenon is shown to be due to depth-dependent defect imbalances created under ion irradiation. These findings demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extraction and interpretation of ion-induced swelling data. 2014 El