WorldWideScience

Sample records for atomic displacements kirchhoff

  1. Fractal dimensionality of cascades of atomic displacements

    International Nuclear Information System (INIS)

    The cascades of opening displacements, formed during irradiation of solids are the most typical process of dissipation of the energy of incident particles and the generation of radiation defects. The aim of the present work is the examination of the energy dependence of the fractal dimensionality of the cascades of atomic displacements in the solid

  2. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    Hitesh Sharma; S Prakash

    2007-04-01

    We present here a systematic investigation of the atomic displacements in bcc transition metal (TM) dilute alloys. We have calculated the atomic displacements in bcc (V, Cr, Fe, Nb, Mo, Ta and W) transition metals (TMs) due to 3d, 4d and 5d TMs at the substitutional site using the Kanzaki lattice static method. Wills and Harrison interatomic potential is used to calculate the atomic force constants, the dynamical matrix and the impurity-induced forces. We have thoroughly investigated the atomic displacements using impurities from 3d, 4d and 5d series in the same host metal and the same impurity in different hosts. We have observed a systematic pattern in the atomic displacements for Cr-, Fe-, Nb-, Mo-, Ta- and W-based dilute alloys. The atomic displacements are found to increase with increase in the number of d electrons for all alloys considered except for V dilute alloys. The 3d impurities are found to be more easily dissolved in the 3d host metals than 4d or 5d TMs whereas 4d and 5d impurities show more solubility in 4d and 5d TMs. In general, the relaxation energy calculation suggests that impurities may be easily solvable in 5d TM hosts when compared to 3d or 4d TMs.

  3. Generalized atomic displacements in crystallographie structure analysis

    International Nuclear Information System (INIS)

    An attempt is made to summarize both theoretical and experimental aspects of generalized atomic displacement parameters (ADP's) in crystalline matter. Generalized displacement parameters are used to describe the weakening of Bragg intensities via the anharmonic (static or thermal) Debye-Waller factor (DWF) and its real-space counterpart, the generalized atomic probability density function (p.d.f.). The lattice dynamical base of the harmonic and anharmonic thermal DWF is discussed. It is pointed out that the static DWF frequently contains higher-order terms. The mathematical case for an experimental determination of generalized ADP's is given. The most popular current formulations (one-particle potential and statistical approaches) are reviewed and their individual limitations are discussed. Likewise the demands put on the quality and extent of experimental data are assessed. Some aids to the interpretation of generalized ADP's established by crystallographic least-squares procedures are given and a Monte-Carlo method for the calculation of errors in p.d.f. maps is presented. Finally, some prospects for future work are outlined and a more frequent comparison of theoretical calculations and experimental determinations of generalized ADP's is advocated. (orig.)

  4. Quantum Phonon Optics: Coherent and Squeezed Atomic Displacements

    OpenAIRE

    Hu, X; Nori, Franco

    1996-01-01

    In this paper we investigate coherent and squeezed quantum states of phonons. The latter allow the possibility of modulating the quantum fluctuations of atomic displacements below the zero-point quantum noise level of coherent states. The expectation values and quantum fluctuations of both the atomic displacement and the lattice amplitude operators are calculated in these states---in some cases analytically. We also study the possibility of squeezing quantum noise in the atomic displacement u...

  5. Atomic displacements in ferroelectric trigonal and orthorhombic boracite structures

    Science.gov (United States)

    Dowty, Eric; Clark, J.R.

    1972-01-01

    New crystal-structure refinements of Pca21 boracite, Mg3ClB7O13, and R??{lunate}c ericaite, Fe2.4Mg0.6ClB7O13, show that some boron and oxygen atoms are involved in the 'ferro' transitions as well as the metal and halogen atoms. The atomic displacements associated with the polarity changes are as large as 0.6A??. ?? 1972.

  6. Finding New Thermoelectric Compounds Using Crystallographic Data: Atomic Displacement Parameters

    International Nuclear Information System (INIS)

    A new structure-property relationship is discussed which links atomic displacement parameters (ADPs) and the lattice thermal conductivity of clathrate-like compounds. For many clathrate-like compounds, in which one of the atom types is weakly bound and ''rattles'' within its atomic cage, room temperature ADP information can be used to estimate the room temperature lattice thermal conductivity, the vibration frequency of the ''rattler'', and the temperature dependence of the heat capacity. Neutron data and X-ray crystallography data, reported in the literature, are used to apply this analysis to several promising classes of thermoelectric materials

  7. Atomic displacements due to interstitial hydrogen in Cu and Pd

    Indian Academy of Sciences (India)

    Hitesh Sharma; S Prakash

    2007-08-01

    The density functional theory (DFT) is used to study the atomic interactions in transition metal-based interstitial alloys. The strain field is calculated in the discrete lattice model using Kanzaki method. The total energy and hence atomic forces between interstitial hydrogen and transition metal hosts are calculated using DFT. The norm-conserving pseudopotentials for H, Cu and Pd are generated self-consistently. The dynamical matrices are evaluated considering interaction up to first nearest neighbors whereas impurity-induced forces are calculated with M32H shell (where M = Cu and Pd). The atomic displacements produced by interstitial hydrogen at the octahedral site in Cu and Pd show displacements of 7.36% and 4.3% of the first nearest neighbors respectively. Both Cu and Pd lattices show lattice expansion due to the presence of hydrogen and the obtained average lattice expansion / = 0.177 for Cu and 0.145 for Pd.

  8. Atomic displacements in dilute alloys of Cr, Nb and Mo

    Indian Academy of Sciences (India)

    Hitesh Sharma; S Prakash

    2002-09-01

    Kanzaki lattice static method is used to calculate the atomic displacements due to substitutional impurities in 3d (Cr) and 4d (Nb, Mo) metals. Wills and Harrison interatomic potential is used to calculate dynamical matrix and the impurity-induced forces up to second nearest neighbors. The calculated atomic displacements for 3d, 4d and 5d impurities in Cr (V, Mn, Fe, Ni, Nb, Mo, Ta and W), Nb (V, Cr, Mn, Fe, Zr, Mo, Ta and W) and Mo (V, Cr, Mn, Fe, Zr, Nb, Ta and W) are tabulated up to 10 NN’s. The strain field due to 3d impurities is least in Cr metal while it is larger in Nb and Mo metals. For 4d and 5d impurities the strain is larger in Cr metal than in Nb and Mo hosts. Similar trend is found for relaxation energies also.

  9. Atomic displacements in dilute alloys of Cr, Nb and Mo

    CERN Document Server

    Sharma, H

    2002-01-01

    Kanzaki lattice static method is used to calculate the atomic displacements due to substitutional impurities in 3d (Cr) and 4d (Nb, Mo) metals. Wills and Harrison interatomic potential is used to calculate dynamical matrix and the impurity-induced forces up to second nearest neighbors. The calculated atomic displacements for 3d, 4d and 5d impurities in Cr (V, Mn, Fe, Ni, Nb, Mo, Ta and W), Nb (V, Cr, Mn, Fe, Zr, Mo, Ta and W) and Mo (V, Cr, Mn, Fe, Zr, Nb, Ta and W) are tabulated up to 10 NN's. The strain field due to 3d impurities is least in Cr metal while it is larger in Nb and Mo metals. For 4d and 5d impurities the strain is larger in Cr metal than in Nb and Mo hosts. Similar trend is found for relaxation energies also. (author)

  10. Generalized Kirchhoff law

    CERN Document Server

    Greffet, Jean-Jacques; Brucoli, Giovanni; Sakat, Emilie; Marquier, François

    2016-01-01

    Thermal emission can be conveniently described using Kirchhoff law which states that the emissivity is equal to the absorptivity for isothermal bodies. For a finite size system, absorptivity is replaced by an absorption cross section. Here, we study the link between thermal emission and absorption by a finite size object which is not isothermal. We define a local absorption rate for a given incident plane wave and we prove that it is equal to the local emissivity rate. Hence, Kirchhoff law can be extended to anisothermal media. A practical consequence is the possibility of analysing thermal radiation by a variety of non-equilibrium systems such as microwave radiation in geophysical remote sensing or X-UV radiation by plasmas. This result provides a theoretical framework to analyse thermal emission by hot electrons in quantum wells, tunnel junctions or graphene. It paves the way to the design of a new generation of incandescent emitters made of subwavelength hot emitters coupled to cold antennas. The antennas ...

  11. Mean-squared atomic displacements in hydrated lysozyme, native and denatured

    OpenAIRE

    Mamontov, Eugene; O’Neill, Hugh; Zhang, Qiu

    2010-01-01

    We use elastic neutron scattering to demonstrate that a sharp increase in the mean-squared atomic displacements, commonly observed in hydrated proteins above 200 K and often referred to as the dynamical transition, is present in the hydrated state of both native and denatured lysozyme. A direct comparison of the native and denatured protein thus confirms that the presence of the transition in the mean-squared atomic displacements is not specific to biologically functional molecules.

  12. Atomic structure of cascades of atomic displacements in metals and alloys after different types of radiation

    Science.gov (United States)

    Ivchenko, V. A.

    2016-02-01

    Using the methods of field ion microscopy, we studied radiation induced defects on an atomically clean surface and within a subsurface volume of platinum initiated by the interaction of neutron (E > 0.1MeV) and Ar+ beams (E = 30 keV). It is shown that the interaction of fast neutrons (E > 0.1 MeV) F = 6.7-1021 m-2, F = 3.5-1022 m-2 with matter leads to the formation in the amount of platinum such as radiation damage which occur after ion irradiation by beams of charged Ar+ ions with E = 30 keV, F = 1020 ion/m2. They are observed at a depth of about 1.5-2 nm irradiated under the surface of Pt by ions Ar+. Thus, we have carried out modeling of neutron impact with matter when replacing the neutron beam by an ion beam that causes the same radiation damage in the bulk of the material. Experimental results on atomic-spatial investigation of radiative defect formation in surface layers of materials, initiated by neutron bombardment (of Pt, E > 0.1 MeV) and ion implantation (in Cu3Au: E = 40 keV, F = 1020 ion/m2, j = 10-3 A/cm2), are considered. Quantitative estimates obtained for the size, shape, and volume fraction of cascades of atomic displacements formed under various types of irradiation in the surface layers of the materials. It is showing that the average size of radiation clusters after irradiation of platinum to a fast neutron fluence of 6.7-1022 m-2 (E > 0.1 MeV) is about 3.2 nm. The experimentally established average size of a radiation cluster (disordered zone) in the alloy after ion bombardment is 4×4×1.5 nm.

  13. Gamma induced atom displacements in LYSO and LuYAP crystals as used in medical imaging applications

    Energy Technology Data Exchange (ETDEWEB)

    Piñera, Ibrahin, E-mail: ipinera@ceaden.edu.cu [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, CEADEN, 30 St. 502, Playa 11300, Havana (Cuba); Cruz, Carlos M.; Abreu, Yamiel; Leyva, Antonio [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, CEADEN, 30 St. 502, Playa 11300, Havana (Cuba); Van Espen, Piet [University of Antwerp, CGB, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Díaz, Angelina; Cabal, Ana E. [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, CEADEN, 30 St. 502, Playa 11300, Havana (Cuba); Van Remortel, Nick [University of Antwerp, CGB, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)

    2015-08-01

    The radiation damage, in terms of atom displacements, induced by gamma irradiation in LYSO and LuYAP crystals is presented. {sup 44}Sc, {sup 22}Na and {sup 48}V are used as gamma sources for this study. The energy of gammas from the electron–positron annihilation processes (511 keV) is also included in the study. The atom displacements distributions inside each material are calculated following the Monte Carlo assisted Classical Method introduced by the authors. This procedure also allows to study the atom displacements in-depth distributions inside each crystal. The atom displacements damage in LYSO crystals is found to be higher than in LuYAP crystals, mainly provoked by the displacements of silicon and oxygen atoms. But the difference between atom displacements produced in LYSO and LuYAP decreases when more energetic sources are used. On the other hand, the correlation between the atom displacements and energy deposition in-depth distributions is excellent. The atom displacements to energy deposition ratio is found to increases with more energetic photon sources. LYSO crystals are then more liable to the atom displacements damage than LuYAP crystals.

  14. Gamma induced atom displacements in LYSO and LuYAP crystals as used in medical imaging applications

    International Nuclear Information System (INIS)

    The radiation damage, in terms of atom displacements, induced by gamma irradiation in LYSO and LuYAP crystals is presented. 44Sc, 22Na and 48V are used as gamma sources for this study. The energy of gammas from the electron–positron annihilation processes (511 keV) is also included in the study. The atom displacements distributions inside each material are calculated following the Monte Carlo assisted Classical Method introduced by the authors. This procedure also allows to study the atom displacements in-depth distributions inside each crystal. The atom displacements damage in LYSO crystals is found to be higher than in LuYAP crystals, mainly provoked by the displacements of silicon and oxygen atoms. But the difference between atom displacements produced in LYSO and LuYAP decreases when more energetic sources are used. On the other hand, the correlation between the atom displacements and energy deposition in-depth distributions is excellent. The atom displacements to energy deposition ratio is found to increases with more energetic photon sources. LYSO crystals are then more liable to the atom displacements damage than LuYAP crystals

  15. Entropy and Entanglement of the Superpositions of Displaced Fock States with a Two-Level Atom

    Science.gov (United States)

    Abd Al-Kader, Gamal M.

    The properties of the displaced Fock states (DFS's) superpositions are reviewed. The interaction of these states with a two-level atom in cavity with the presence of additional Kerr medium is studied. Exact general matrix elements of the time-dependent operators of a Jaynes-Cummings model (JCM), in the presence of a Kerr medium, with these states are derived. The atomic inversion and photon number distribution are discussed. The quantum entropy and the entanglement of the atom-field are investigated. The exact results are employed to perform a careful investigation of the temporal evolution of the entropy. The connection between the field entropy and the collapses and revivals of the atomic inversion has been established. The general conclusions reached are illustrated by numerical results.

  16. Improved calculation of displacements per atom cross section in solids by gamma and electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Piñera, Ibrahin, E-mail: ipinera@ceaden.edu.cu [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, CEADEN, 30 St. 502, Playa 11300, Havana (Cuba); Cruz, Carlos M.; Leyva, Antonio; Abreu, Yamiel; Cabal, Ana E. [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, CEADEN, 30 St. 502, Playa 11300, Havana (Cuba); Espen, Piet Van; Remortel, Nick Van [University of Antwerp, CGB, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)

    2014-11-15

    Highlights: • We present a calculation procedure for dpa cross section in solids under irradiation. • Improvement about 10–90% for the gamma irradiation induced dpa cross section. • Improvement about 5–50% for the electron irradiation induced dpa cross section. • More precise results (20–70%) for thin samples irradiated with electrons. - Abstract: Several authors had estimated the displacements per atom cross sections under different approximations and models, including most of the main gamma- and electron-material interaction processes. These previous works used numerical approximation formulas which are applicable for limited energy ranges. We proposed the Monte Carlo assisted Classical Method (MCCM), which relates the established theories about atom displacements to the electron and positron secondary fluence distributions calculated from the Monte Carlo simulation. In this study the MCCM procedure is adapted in order to estimate the displacements per atom cross sections for gamma and electron irradiation. The results obtained through this procedure are compared with previous theoretical calculations. An improvement in about 10–90% for the gamma irradiation induced dpa cross section is observed in our results on regard to the previous evaluations for the studied incident energies. On the other hand, the dpa cross section values produced by irradiation with electrons are improved by our calculations in about 5–50% when compared with the theoretical approximations. When thin samples are irradiated with electrons, more precise results are obtained through the MCCM (in about 20–70%) with respect to the previous studies.

  17. Improved calculation of displacements per atom cross section in solids by gamma and electron irradiation

    International Nuclear Information System (INIS)

    Highlights: • We present a calculation procedure for dpa cross section in solids under irradiation. • Improvement about 10–90% for the gamma irradiation induced dpa cross section. • Improvement about 5–50% for the electron irradiation induced dpa cross section. • More precise results (20–70%) for thin samples irradiated with electrons. - Abstract: Several authors had estimated the displacements per atom cross sections under different approximations and models, including most of the main gamma- and electron-material interaction processes. These previous works used numerical approximation formulas which are applicable for limited energy ranges. We proposed the Monte Carlo assisted Classical Method (MCCM), which relates the established theories about atom displacements to the electron and positron secondary fluence distributions calculated from the Monte Carlo simulation. In this study the MCCM procedure is adapted in order to estimate the displacements per atom cross sections for gamma and electron irradiation. The results obtained through this procedure are compared with previous theoretical calculations. An improvement in about 10–90% for the gamma irradiation induced dpa cross section is observed in our results on regard to the previous evaluations for the studied incident energies. On the other hand, the dpa cross section values produced by irradiation with electrons are improved by our calculations in about 5–50% when compared with the theoretical approximations. When thin samples are irradiated with electrons, more precise results are obtained through the MCCM (in about 20–70%) with respect to the previous studies

  18. Atomic Force Microscopy in Dynamic Mode with Displacement Current Detection in Double Cantilever Devices

    Science.gov (United States)

    Müller, Falk; Müller, Anne‑Dorothea; Hietschold, Michael; Gessner, Thomas

    2006-03-01

    A cantilever array for dynamic mode atomic force microscopy (AFM) is presented, the vertical displacement of which is analyzed by the detection of displacement currents in the electrodes. Each cantilever in the array consists of an actuation part that allows an independent vertical movement, and a sensor part. The lateral distance between the tips of the different cantilevers is fixed to 10 μm. When operated as an actuator, a voltage is applied between the silicon membrane and the underlaying electrode. Due to the resulting coulomb forces, the vertical position of the tip is controllable. The reaction time in this mode is shorter than the response time of a piezostack. The sensor part, on the other hand, allows the device to work in dynamic mode without a laser deflection system. The vertical resolution achieved is below 1 nm. The dependence of force distance curves on the excitation amplitude is shown.

  19. Annealing kinetics of single displacement cascades in Ni: An atomic scale computer simulation

    International Nuclear Information System (INIS)

    In order to describe the long term evolution of the defects produced by a displacement cascade, Molecular dynamics (MD) and Kinetic Monte Carlo (KMC) methods are employed. Using an empirical Ni interatomic potential in MD, the damage resulting from primary knock-on atom (PKA) energies up to 30 keV has been simulated. The annealing kinetics and the fraction of freely migrating defects (FMD) are determined for each single displacement cascade, by a KMC code which is based on a set of parameters extracted mainly from MD simulations. It allows an atomistic study of the evolution of the initial damage over a time scale up to 100s and the determination of the fraction of the defects that escape the KMC box, compared to those obtained by MD, as function of temperature and PKA energy. It has been found that this fraction depends strongly on the temperature but reaches a saturation value above stage V

  20. Temperature dependent local atomic displacements in ammonia intercalated iron selenide superconductor

    Science.gov (United States)

    Paris, E.; Simonelli, L.; Wakita, T.; Marini, C.; Lee, J.-H.; Olszewski, W.; Terashima, K.; Kakuto, T.; Nishimoto, N.; Kimura, T.; Kudo, K.; Kambe, T.; Nohara, M.; Yokoya, T.; Saini, N. L.

    2016-01-01

    Recently, ammonia-thermal reaction has been used for molecular intercalation in layered FeSe, resulting a new Lix(NH3)yFe2Se2 superconductor with Tc ~ 45 K. Here, we have used temperature dependent extended x-ray absorption fine structure (EXAFS) to investigate local atomic displacements in single crystals of this new superconductor. Using polarized EXAFS at Fe K-edge we have obtained direct information on the local Fe-Se and Fe-Fe bondlengths and corresponding mean square relative displacements (MSRD). We find that the Se-height in the intercalated system is lower than the one in the binary FeSe, suggesting compressed FeSe4 tetrahedron in the title system. Incidentally, there is hardly any effect of the intercalation on the bondlengths characteristics, revealed by the Einstein temperatures, that are similar to those found in the binary FeSe. Therefore, the molecular intercalation induces an effective compression and decouples the FeSe slabs. Furthermore, the results reveal an anomalous change in the atomic correlations across Tc, appearing as a clear decrease in the MSRD, indicating hardening of the local lattice mode. Similar response of the local lattice has been found in other families of superconductors, e.g., A15-type and cuprates superconductors. This observation suggests that local atomic correlations should have some direct correlation with the superconductivity. PMID:27276997

  1. Computer codes for simulating atomic-displacement cascades in solids subject to irradiation

    International Nuclear Information System (INIS)

    In order to study atomic displacement cascades originating from primary knock-on atoms in solids subject to incident radiation, the simulation code CASCADE/CLUSTER is adapted for use on FACOM/230-75 computer system. In addition, the code is modified so as to plot the defect patterns in crystalline solids. As other simulation code of the cascade process, MARLOWE is also available for use on the FACOM system. To deal with the thermal annealing of point defects produced in the cascade process, the code DAIQUIRI developed originally for body-centered cubic crystals is modified to be applicable also for face-centered cubic lattices. By combining CASCADE/CLUSTER and DAIQUIRI, we then prepared a computer code system CASCSRB to deal with heavy irradiation or saturation damage state of solids at normal temperature. Furthermore, a code system for the simulation of heavy irradiations CASCMARL is available, in which MARLOWE code is substituted for CASCADE in the CASCSRB system. (author)

  2. Kirchhoff's Law of Thermal Emission: 150 Years

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2009-10-01

    Full Text Available In this work, Kirchhoff's law (Kirchhoff G. Monatsberichte der Akademie der Wissenschaften zu Berlin, sessions of Dec. 1859, 1860, 783-787 is being revisited not only to mark its 150th anniversary but, most importantly, to highlight serious overreaching in its formulation. At the onset, Kirchhoff's law correctly outlines the equivalence between emission and absorption for an opaque object under thermal equilibrium. This same conclusion had been established earlier by Balfour Stewart (Stewart B. Trans. Royal Soc. Edinburgh, 1858, v.22(1, 1-20. However, Kirchhoff extends the treatment beyond his counterpart, stating that cavity radiation must always be black, or normal: depending only on the temperature and the frequency of observation. This universal aspect of Kirchhoff's law is without proper basis and constitutes a grave distortion of experimental reality. It is readily apparent that cavities made from arbitrary materials ($varepsilon < 1$ are never black. Their approach to such behavior is being driven either by the blackness of the detector, or by black materials placed near the cavity. Ample evidence exists that radiation in arbitrary cavities is sensitive to the relative position of the detectors. In order to fully address these issues, cavity radiation and the generalization of Kirchhoff's law are discussed. An example is then taken from electromagnetics, at microwave frequencies, to link results in the resonant cavity with those inferred from the consequences of generalization.

  3. Kirchhoff's rule for quantum wires

    International Nuclear Information System (INIS)

    We formulate and discuss one-particle quantum scattering theory on an arbitrary finite graph with n open ends and where we define the Hamiltonian to be (minus) the Laplace operator with general boundary conditions at the vertices. This results in a scattering theory with n channels. The corresponding on-shell S-matrix formed by the reflection and transmission amplitudes for incoming plane waves of energy E>0 is given explicitly in terms of the boundary conditions and the lengths of the internal lines. It is shown to be unitary, which may be viewed as the quantum version of Kirchhoff's law. We exhibit covariance and symmetry properties. It is symmetric if the boundary conditions are real. Also there is a duality transformation on the set of boundary conditions and the lengths of the internal lines such that the low-energy behaviour of one theory gives the high-energy behaviour of the transformed theory. Finally, we provide a composition rule by which the on-shell S-matrix of a graph is factorizable in terms of the S-matrices of its subgraphs. All proofs use only known facts from the theory of self-adjoint extensions, standard linear algebra, complex function theory and elementary arguments from the theory of Hermitian symplectic forms. (author)

  4. Atomic motion from the mean square displacement in a monatomic liquid

    International Nuclear Information System (INIS)

    V-T theory is constructed in the many-body Hamiltonian formulation, and is being developed as a novel approach to liquid dynamics theory. In this theory the liquid atomic motion consists of two contributions, normal mode vibrations in a single representative potential energy valley, and transits, which carry the system across boundaries between valleys. The mean square displacement time correlation function (the MSD) is a direct measure of the atomic motion, and our goal is to determine if the V-T formalism can produce a physically sensible account of this motion. We employ molecular dynamics (MD) data for a system representing liquid Na, and find the motion evolves in three successive time intervals: on the first ‘vibrational’ interval, the vibrational motion alone gives a highly accurate account of the MD data; on the second ‘crossover’ interval, the vibrational MSD saturates to a constant while the transit motion builds up from zero; on the third ‘random walk’ interval, the transit motion produces a purely diffusive random walk of the vibrational equilibrium positions. This motional evolution agrees with, and adds refinement to, the MSD atomic motion as described by current liquid dynamics theories. (paper)

  5. Atomic motion from the mean square displacement in a monatomic liquid

    Science.gov (United States)

    Wallace, Duane C.; De Lorenzi-Venneri, Giulia; Chisolm, Eric D.

    2016-05-01

    V-T theory is constructed in the many-body Hamiltonian formulation, and is being developed as a novel approach to liquid dynamics theory. In this theory the liquid atomic motion consists of two contributions, normal mode vibrations in a single representative potential energy valley, and transits, which carry the system across boundaries between valleys. The mean square displacement time correlation function (the MSD) is a direct measure of the atomic motion, and our goal is to determine if the V-T formalism can produce a physically sensible account of this motion. We employ molecular dynamics (MD) data for a system representing liquid Na, and find the motion evolves in three successive time intervals: on the first ‘vibrational’ interval, the vibrational motion alone gives a highly accurate account of the MD data; on the second ‘crossover’ interval, the vibrational MSD saturates to a constant while the transit motion builds up from zero; on the third ‘random walk’ interval, the transit motion produces a purely diffusive random walk of the vibrational equilibrium positions. This motional evolution agrees with, and adds refinement to, the MSD atomic motion as described by current liquid dynamics theories.

  6. Estimation of Phonon Dispersion Relations Using Correlation Effects Among Thermal Displacements of Atoms

    Directory of Open Access Journals (Sweden)

    Y. Ishikawa

    2015-04-01

    Full Text Available Neutron diffraction measurement of powder α-Fe sample at 295 K was carried out at the high resolution powder diffractometer installed at Japan Proton Accelerator Research Complex (J-PARC. Crystal parameters were determined from Rietveld analysis. The correlation effects among thermal displacements of atoms were estimated from a generalized equation based on the results of fomer diffuse scattering analysis. The force constants among atoms were obtained using an equation for transforming of the correlation effects to force constants. The force constants and the crystal structure of α-Fe were used to estimate the phonon dispersion relations, phonon density of states, and specific heat by computer simulation. The obtained force constants among first-nearest-neighboring atoms is 2.3 eV/Å2 at 295 K and the specific heat is 185 meV/K at 150 K. The calculated phonon dispersion relations and specific heat of α-Fe are similar to those obtained from inelastic neutron scattering and specific heat measurements, respectively

  7. Atomic displacements in the incommensurable charge-density wave in alpha-uranium

    International Nuclear Information System (INIS)

    A detailed examination is presented of the incommensurable charge-density wave (ICDW) in α-uranium below 43K. The q vectors have been measured as a function of temperature and the structure factors of a large number of first-order satellites with neutron diffraction. From the structure factors the atomic displacements that occur at the onset of the CDW have been determined in all three independent crystallographic directions. Uniaxial stress up to 3.5kbar has been applied along 2 directions but does not change the satellite intensities, thus leaving ambiguity whether the structure is single or multi q. The relationship between the present results and the observations of Smith et al is discussed. (author)

  8. Evolution of the superposition of displaced number states with the two-atom multiphoton Jaynes Cummings model: interference and entanglement

    Science.gov (United States)

    El-Orany, Faisal A. A.

    2006-11-01

    In this paper, we study the evolution of two two-level atoms interacting with a single-mode quantized radiation field, namely, the two-atom multiphoton Jaynes-Cummings model (JCM). We assume that the field and the atoms are initially prepared in the superposition of displaced number states and excited atomic states, respectively. For this system, we investigate the atomic inversion, Wigner function, phase distribution and entanglement. We show that for symmetric (asymmetric) atoms, the system can generate asymmetric (symmetric) cat states at a quarter of the revival time. Furthermore, the degrees of entanglement for the field-atoms and the one-atom-remainder tangles depend on the rate of energy flow between the parties. The interference in phase space decreases the degree of entanglement in the bipartite.

  9. Kirchhoff?s generalised law applied to amorphous silicon / crystalline silicon heterostructures

    OpenAIRE

    Brüggemann, Rudolf

    2009-01-01

    Abstract The electro- and photoluminescence spectra of amorphous silicon / crystalline silicon heterostructures and solar cells are determined by emission from the crystalline-silicon layer and are computed with Kirchhoff?s generalised law. The interface defect density strongly influences the luminescence yield which may be used to monitor the interface quality. Based on a comparison between numerical and analytically determined spectra, the temperature dependence of experimental e...

  10. Disparate atomic displacements in skutterudite-type LaFe3CoSb12, a model for thermoelectric behavior

    International Nuclear Information System (INIS)

    Mean-square atomic displacement in lanthanum triiron cobalt dodecaantimonide, determined as a function of temperature using single-crystal neutron diffraction, show that the La atom exhibits an anomalously large displacement at room temperature, Ueq = 0.0196 (9) A2, because it is too small to fill the atomic cage formed by the corner-linked octahedral framework of M4Sb12, M = Fe, Co. Site-occupancy refinements show 25% vacancies on the La site and an actual Fe:Co ratio of 2.17:1. Analysis of the temperature dependence of the atomic displacements identifies a significant temperature-independent component for the La atom ascribed to static disorder, which amounts to 19% of the room-temperature value. The large-amplitude rattling of the La atom can be effectively linked to the dramatic decrease of the lattice contribution to the thermal conductivity, which is a key factor for improving the thermoelectric behavior of these materials. This structure-property relationship offers a new paradigm for the exploration of thermoelectric materials. (orig.)

  11. Disparate atomic displacements in skutterudite-type LaFe3CoSb12, a model for thermoelectric behavior.

    Science.gov (United States)

    Chakoumakos; Sales; Mandrus; Keppens

    1999-06-01

    Mean-square atomic displacements in lanthanum triiron cobalt dodecaantimonide, determined as a function of temperature using single-crystal neutron diffraction, show that the La atom exhibits an anomalously large displacement at room temperature, U(eq) = 0.0196 (9) Å(2), because it is too small to fill the atomic cage formed by the corner-linked octahedral framework of M(4)Sb(12), M = Fe, Co. Site-occupancy refinements show 25% vacancies on the La site and an actual Fe:Co ratio of 2.17:1. Analysis of the temperature dependence of the atomic displacements identifies a significant temperature-independent component for the La atom ascribed to static disorder, which amounts to 19% of the room-temperature value. The large-amplitude rattling of the La atom can be effectively linked to the dramatic decrease of the lattice contribution to the thermal conductivity, which is a key factor for improving the thermoelectric behavior of these materials. This structure-property relationship offers a new paradigm for the exploration of thermoelectric materials. PMID:10927376

  12. Mean-square displacement of atomic complex in titanium carbonitrides TiCxNy

    International Nuclear Information System (INIS)

    Full text: The atomic mean-square displacement (MSD) is one of important characteristics of solids, and one can use it for determination of a number of other characteristics of substances. In this work the MSD of atomic complex were determined for a number of compositions of the cubic titanium carbonitrides TiCxNy using the neutron powder diffraction data. The error of MSD determination was less than 3 %. When determining intensity of diffraction maximum a correction for the thermal diffusion dispersion (TDD) was included in the neutron diffraction patterns. The contribution of TDD in the intensity of diffraction maxima was found to be less than the experiment error (no more than 1,5 %). Such small value of the TDD correction is explained by refractory of materials. The values of MSD in titanium carbonitrides for a number of compositions, determined by the neutron powder diffraction measurements, are given. It is shown, that the dependence of MSD on the concentration (C+N)/Ti has a complex character. With decrease of the total content of metalloids MSD decreases at first, reaching a minimum about concentration (C+N)/Ti≅0.80, and then increases. MSD consists of dynamic and static distortions, where the static distortions in the compounds with variable composition increase with increasing of deviation from stoichiometry. The above anomaly in the dependence of MSD on the total concentration of metalloids, apparently, point to prevalence of dynamic distortions over static ones and to complex character of concentration dependence of interatomic interactions in the titanium carbonitrides. This work was supported by the Supporting Fund for Fundamental Researches of Uzbekistan Academy of Sciences (Grant No. 6-04)

  13. Separate determination of the amplitude of thermal vibrations and static atomic displacements in titanium carbide by neutron diffraction

    International Nuclear Information System (INIS)

    The amplitude of thermal (dynamic) atomic vibrations and meansquare static atomic displacements in titanium carbide TiCx (x = 0.97, 0.88, 0.70) have been separately determined by measuring neutron diffraction patterns at two temperatures (T1 = 300 K and T2 = 80 K). The static lattice distortions in stoichiometric titanium carbide are experimentally found to be negligible. In the TiCx homogeneity range, the amplitude √u2dyn of thermal atomic vibrations significantly increases with a decrease in the carbon concentration. The Debye temperature has been determined for the first time in the TiCx homogeneity range at both room and liquid-nitrogen temperatures.

  14. Estimated H-atom anisotropic displacement parameters: a comparison between different methods and with neutron diffraction results

    DEFF Research Database (Denmark)

    Munshi, Parthapratim; Madsen, Anders Ø; Spackman, Mark A; Larsen, Sine; Destro, Riccardo

    Anisotropic displacement parameters (ADPs) are compared for H atoms estimated using three recently described procedures, both among themselves and with neutron diffraction results. The results convincingly demonstrate that all methods are capable of giving excellent results for several benchmark...... results is substantial, suggesting that this is now the most readily and widely applicable of the three approximate procedures. Using this new library--SHADE2--it is shown that, in line with expectations, a segmented rigid-body description of the heavy atoms yields only a small improvement in the...... agreement with neutron results. The SHADE2 library, now incorporated in the SHADE web server, is recommended as a routine procedure for deriving estimates of H-atom ADPs suitable for use in charge-density studies on molecular crystals, and its widespread use should reveal remaining deficiencies and perhaps...

  15. Kirchhoff voltage law corrected for radiating circuits

    CERN Document Server

    Lara, Vitor

    2014-01-01

    When a circular loop composed by a RLC is put to oscillate, the oscillation will eventually vanish in an exponentially decaying current, even considering superconducting wires, due to the emission of electric and magnetic dipole radiation. In this work we propose a modification on the Kirchhoff voltage law by adding the radiative contributions to the energy loss as an effective resistance, whose value is relatively small when compared to typical resistance value, but fundamental to describe correctly real circuits. We have also analysed the change in the pattern of the radiation spectra emitted by the circuit as we vary both the effective and electrical resistance.

  16. Charge-screening role of c -axis atomic displacements in YBa2Cu3O6 +x and related superconductors

    Science.gov (United States)

    Božin, E. S.; Huq, A.; Shen, Bing; Claus, H.; Kwok, W. K.; Tranquada, J. M.

    2016-02-01

    The importance of charge reservoir layers for supplying holes to the CuO2 planes of cuprate superconductors has long been recognized. Less attention has been paid to the screening of the charge transfer by the intervening ionic layers. We address this issue in the case of YBa2Cu3O6 +x , where CuO chains supply the holes for the planes. We present a simple dielectric-screening model that gives a linear correlation between the relative displacements of ions along the c axis, determined by neutron powder diffraction, and the hole density of the planes. Applying this model to the temperature-dependent shifts of ions along the c axis, we infer a charge transfer of 5-10% of the hole density from the planes to the chains on warming from the superconducting transition to room temperature. Given the significant coupling of c -axis displacements to the average charge density, we point out the relevance of local displacements for screening charge modulations and note recent evidence for dynamic screening of in-plane quasiparticles. This line of argument leads us to a simple model for atomic displacements and charge modulation that is consistent with images from scanning-tunneling microscopy for underdoped Bi2Sr2CaCu2O8 +δ .

  17. Atomic displacements effects on the electronic properties of Bi2Sr2Ca2Cu3O10

    International Nuclear Information System (INIS)

    The displacements effects of the oxygen atom associated to the Sr-plane (O3) in the electronic properties of Bi2Sr2Ca2Cu3O10 (Bi-2223), have been investigated using density functional theory. We determined intervals of the O3 atomic positions for which the band structure calculations show that the Bi-O bands, around the high symmetry point M in the irreducible Brillouin zone, emerge towards higher energies avoiding its contribution at Fermi level, as experimentally has been reported. This procedure does not introduce foreign doping elements into the calculation. Our calculations present a good agreement with the angle-resolved photoemission spectroscopy and nuclear magnetic resonance (NMR) experiments. The two options found differ in character (metallic or nonmetallic) of the Bi-O plane. The are not any experiments, to the best of our knowledge, which determine this character for Bi-2223. (Author)

  18. Small atomic displacements in the molybdenophosphates AMo2P3O12 (A = K, Rb, Tl)

    International Nuclear Information System (INIS)

    KMo2P3O12, Mr = 515.90, orthorhombic, Pbnm, a = 17.6398(14), b = 9.1761(4), c = 12.3000(8) A, V = 1990.9(4) A3, Z=8, Dx = 3.44 Mg m-3, λ(Mo Kα) = 0.71069 A, μ = 3.42 mm-1, F(000) = 1952. T = 294 K, R = 0.028 for 2123 reflections. RbMo2P3O12, Mr = 562.26, orthorhombic, Pbcm, a = 8.8314(8), b = 9.2368(7), c = 12.3051(9) A, V = 1003.8(4) A3, Z=4, Dx = 3.72 Mg m-3, λ(Mo Kα) = 0.71069 A, μ = 8.08 mm-1, F(000) = 1048, T = 294 K, R = 0.044 for 2073 reflections. The Mo2P3O12 frameworks of the K, Rb and Tl compounds are almost the same. The main difference is in the position of the alkaline-earth ions in the tunnels, which induces, in the potassium compound, a superstructure along a. The alkaline-earth ions are slightly displaced as their size decreases in order that the A-O distances may agree with the sum of the ionic radii. (orig.)

  19. Kirchhoff e os fundamentos da mecânica

    Directory of Open Access Journals (Sweden)

    Antonio Augusto Passos Videira

    2011-01-01

    Full Text Available Este artigo descreve as ideias fundamentais da concepção de mecânica defendida por Kirchhoff em seu célebre tratado dedicado a essa ciência e publicado originalmente em 1876. Comenta-se também a ausência de razões dadas pelo próprio Kirchhoff em favor de suas concepções. Defendemos a hipótese de que o seu silêncio explica-se pela vontade de não produzir ou reforçar debates sobre os fundamentos da mecânica. Em outros termos, Kirchhoff cala-se para não ter que debater com os filósofos, principalmente aqueles de inspiração idealista ou hegeliana.This article describes the most important ideas of Kirchhoff's conception of mechanics as he formulated it in the first edition of his famous treatise on this science, published in 1876. It also discusses why Kirchhoff did not explicitly present arguments in favor of his conception, and argues that his silence can be explained by his refusal to take part in debates on the foundations of mechanics. In other words, Kirchhoff kept silent because he did not want to engage in discussion with philosophers, especially those inspired by Idealism or Hegelianism.

  20. New developments on Monte Carlo simulation code for the calculation of Atom Displacements Induced rates by High Energy Electrons in Solid Materials

    International Nuclear Information System (INIS)

    New developments and simulations on regard to the interactions of incident gamma radiation over solids materials using the MCSAD (Monte Carlo Simulation of Atom Displacement) code are presented. In this code Monte Carlo algorithms are applied in order to sample all electrons and gamma interaction processes occurring during their transport through a solid target, especially those connected to the output of atom displacements events. Particularly, it is calculated the limit angle to elastic scattering for the electrons on a new approach, which allows correctly the splitting of the electron single processes at higher scattering angles. On this way, the probability of single electron scattering processes transferring high recoil atomic energy leading to atom displacement effects is calculated and consequently sampled in the MCSAD code. In addition, it is considered some other new theoretical aspects in order to improve previous versions, like the one concerning the selection of threshold energy for displacements at a given atom site in dependence of the atom recoil direction. (Author)

  1. Measurement of transient atomic displacements in thin films with picosecond and femtometer resolution.

    Science.gov (United States)

    Kozina, M; Hu, T; Wittenberg, J S; Szilagyi, E; Trigo, M; Miller, T A; Uher, C; Damodaran, A; Martin, L; Mehta, A; Corbett, J; Safranek, J; Reis, D A; Lindenberg, A M

    2014-05-01

    We report measurements of the transient structural response of weakly photo-excited thin films of BiFeO3, Pb(Zr,Ti)O3, and Bi and time-scales for interfacial thermal transport. Utilizing picosecond x-ray diffraction at a 1.28 MHz repetition rate with time resolution extending down to 15 ps, transient changes in the diffraction angle are recorded. These changes are associated with photo-induced lattice strains within nanolayer thin films, resolved at the part-per-million level, corresponding to a shift in the scattering angle three orders of magnitude smaller than the rocking curve width and changes in the interlayer lattice spacing of fractions of a femtometer. The combination of high brightness, repetition rate, and stability of the synchrotron, in conjunction with high time resolution, represents a novel means to probe atomic-scale, near-equilibrium dynamics. PMID:26798776

  2. Measurement of transient atomic displacements in thin films with picosecond and femtometer resolution

    Directory of Open Access Journals (Sweden)

    M. Kozina

    2014-05-01

    Full Text Available We report measurements of the transient structural response of weakly photo-excited thin films of BiFeO3, Pb(Zr,TiO3, and Bi and time-scales for interfacial thermal transport. Utilizing picosecond x-ray diffraction at a 1.28 MHz repetition rate with time resolution extending down to 15 ps, transient changes in the diffraction angle are recorded. These changes are associated with photo-induced lattice strains within nanolayer thin films, resolved at the part-per-million level, corresponding to a shift in the scattering angle three orders of magnitude smaller than the rocking curve width and changes in the interlayer lattice spacing of fractions of a femtometer. The combination of high brightness, repetition rate, and stability of the synchrotron, in conjunction with high time resolution, represents a novel means to probe atomic-scale, near-equilibrium dynamics.

  3. Giant atomic displacement at a magnetic phase transition in metastable Mn3O4

    Energy Technology Data Exchange (ETDEWEB)

    Hirai, Shigeto [Stanford University; Moreira Dos Santos, Antonio F [ORNL; Shapiro, Max C [Stanford University; Molaison, Jamie J [ORNL; Pradhan, Neelam [ORNL; Guthrie, Malcolm [Carnegie Institution of Washington; Tulk, Christopher A [ORNL; Fisher, Ian R [Stanford University; Mao, Wendy [Stanford University

    2013-01-01

    We present x-ray, neutron scattering, and heat capacity data that reveal a coupled first-order magnetic and structural phase transition of the metastable mixed-valence postspinel compound Mn3O4 at 210 K. Powder neutron diffraction measurements reveal a magnetic structure in which Mn3+ spins align antiferromagnetically along the edge-sharing a axis, with a magnetic propagation vector k = [1/2,0,0]. In contrast, the Mn2+ spins, which are geometrically frustrated, do not order until a much lower temperature. Although the Mn2+ spins do not directly participate in the magnetic phase transition at 210 K, structural refinements reveal a large atomic shift at this phase transition, corresponding to a physical motion of approximately 0.25 angstrom, even though the crystal symmetry remains unchanged. This "giant" response is due to the coupled effect of built-in strain in the metastable postspinel structure with the orbital realignment of the Mn3+ ion.

  4. Detection of atomic force microscopy cantilever displacement with a transmitted electron beam

    Science.gov (United States)

    Wagner, R.; Woehl, T. J.; Keller, R. R.; Killgore, J. P.

    2016-07-01

    The response time of an atomic force microscopy (AFM) cantilever can be decreased by reducing cantilever size; however, the fastest AFM cantilevers are currently nearing the smallest size that can be detected with the conventional optical lever approach. Here, we demonstrate an electron beam detection scheme for measuring AFM cantilever oscillations. The oscillating AFM tip is positioned perpendicular to and in the path of a stationary focused nanometer sized electron beam. As the tip oscillates, the thickness of the material under the electron beam changes, causing a fluctuation in the number of scattered transmitted electrons that are detected. We demonstrate detection of sub-nanometer vibration amplitudes with an electron beam, providing a pathway for dynamic AFM with cantilevers that are orders of magnitude smaller and faster than the current state of the art.

  5. Molecular dynamics modeling of atomic displacement cascades in 3C-SiC: Comparison of interatomic potentials

    International Nuclear Information System (INIS)

    We used molecular dynamics modeling of atomic displacement cascades to characterize the nature of primary radiation damage in 3C-SiC. We demonstrated that the most commonly used interatomic potentials are inconsistent with ab initio calculations of defect energetics. Both the Tersoff potential used in this work and a modified embedded-atom method potential reveal a barrier to recombination of the carbon interstitial and carbon vacancy which is much higher than the density functional theory (DFT) results. The barrier obtained with a newer potential by Gao and Weber is closer to the DFT result. This difference results in significant differences in the cascade production of point defects. We have completed both 10 keV and 50 keV cascade simulations in 3C-SiC at a range of temperatures. In contrast to the Tersoff potential, the Gao-Weber potential produces almost twice as many C vacancies and interstitials at the time of maximum disorder (∼0.2 ps) but only about 25% more stable defects at the end of the simulation. Only about 20% of the carbon defects produced with the Tersoff potential recombine during the in-cascade annealing phase, while about 60% recombine with the Gao-Weber potential

  6. Cubic Zig-Zag Enrichment of the Classical Kirchhoff Kinematics for Laminated and Sandwich Plates

    Science.gov (United States)

    Nemeth, Michael P.

    2012-01-01

    A detailed anaylsis and examples are presented that show how to enrich the kinematics of classical Kirchhoff plate theory by appending them with a set of continuous piecewise-cubic functions. This analysis is used to obtain functions that contain the effects of laminate heterogeneity and asymmetry on the variations of the inplane displacements and transverse shearing stresses, for use with a {3, 0} plate theory in which these distributions are specified apriori. The functions used for the enrichment are based on the improved zig-zag plate theory presented recently by Tessler, Di Scuva, and Gherlone. With the approach presented herein, the inplane displacements are represented by a set of continuous piecewise-cubic functions, and the transverse shearing stresses and strains are represented by a set of piecewise-quadratic functions that are discontinuous at the ply interfaces.

  7. Electron transfer and ionic displacements as the origin of the 2D electron gas at the LAO/STO interface: Direct measurements with atomic-column spatial resolution.

    Energy Technology Data Exchange (ETDEWEB)

    Cantoni, Claudia [ORNL; Gazquez Alabart, Jaume [ORNL; Miletto Granozio, Fabio [Universita` di Napoli “Federico II”; Oxley, Mark P [ORNL; Varela del Arco, Maria [ORNL; Lupini, Andrew R [ORNL; Pennycook, Stephen J [ORNL; Aruta, Carmela [Universita` di Napoli “Federico II”; Scotti di Uccio, Umberto [Universita` di Napoli “Federico II”; Perna, Paolo [Universita` di Napoli “Federico II”; Maccariello, Davide [Universita` di Napoli “Federico II”

    2012-01-01

    We present direct, atomic-column-resolved scanning transmission electron microscopy and electron energy loss measurements of atomic displacements and Ti valence in abrupt, conductive LAO/STO interfaces. We find that two distinct but interrelated mechanisms are responsible for screening the diverging electric potential in the LAO film: 1) charge injection in the interfacial Ti planes, and 2) dielectric relaxation in both LAO and STO through ionic displacements. The injected charge density decays over a length of nearly 3 unit cells within the STO substrate. The total injected charge is lower than predicted by pure electronic reconstruction. The origin of this discrepancy is attributed to cation and oxygen displacements, which we observe in both LAO and STO, and generate a polarization opposite to the intrinsic polarization of the LAO film. Our data attribute a minor role to oxygen vacancies and cation intermixing.

  8. Focal shifts in diffracted converging electromagnetic waves. I. Kirchhoff theory.

    Science.gov (United States)

    Li, Yajun

    2005-01-01

    Starting with the vector formulation of the Kirchhoff diffraction theory, expressions for the total energy density distribution along the axis are presented without using any of the usual assumptions except the assumption made by Kirchhoff for the boundary conditions of a black screen. To make the Kirchhoff integral compatible with Maxwell's equations, a line integral around the edge of the aperture is added in the analysis. The consequence of ignoring the contribution of this line integral to the axial field distribution is examined numerically. The focal shift effect is investigated for both aplanatic systems and parabolic mirrors having an arbitrary numerical aperture (NA) and finite value of the Fresnel number. The combined effects of the Fresnel number and NA on the focal shift are evaluated, and the validity of the results is carefully checked by comparing the wavelength with the system dimensions. PMID:15669616

  9. Nonhomogeneous elliptic problems of Kirchhoff type involving critical Sobolev exponents

    Directory of Open Access Journals (Sweden)

    Safia Benmansour

    2015-03-01

    Full Text Available This article concerns the existence and the multiplicity of solutions for nonhomogeneous elliptic Kirchhoff problems involving the critical Sobolev exponent, defined on a regular bounded domain of $\\mathbb{R}^3$. Our approach is essentially based on Ekeland's Variational Principle and the Mountain Pass Lemma.

  10. Existence of positive solutions for Kirchhoff type equations

    OpenAIRE

    Ghasem A. Afrouzi; Nguyen Thanh Chung; Saleh Shakeri

    2013-01-01

    In this article, we are interested in the existence of positive solutions for the Kirchhoff type problems $$displaylines{ -MBig(int_{Omega}|abla u|^p,dxBig)Delta_pu = lambda f(u) quad hbox{in } Omega,cr u > 0 quad hbox{in } Omega, quad u =0 quad hbox{on } partialOmega, }$$ where $ 1

  11. Computing prestack Kirchhoff time migration on general purpose GPU

    Science.gov (United States)

    Shi, Xiaohua; Li, Chuang; Wang, Shihu; Wang, Xu

    2011-10-01

    This paper introduces how to optimize a practical prestack Kirchhoff time migration program by the Compute Unified Device Architecture (CUDA) on a general purpose GPU (GPGPU). A few useful optimization methods on GPGPU are demonstrated, such as how to increase the kernel thread numbers on GPU cores, and how to utilize the memory streams to overlap GPU kernel execution time, etc. The floating-point errors on CUDA and NVidia's GPUs are discussed in detail. Some effective methods that can be used to reduce the floating-point errors are introduced. The images generated by the practical prestack Kirchhoff time migration programs for the same real-world seismic data inputs on CPU and GPU are demonstrated. The final GPGPU approach on NVidia GTX 260 is more than 17 times faster than its original CPU version on Intel's P4 3.0G.

  12. A study of temperature dependent local atomic displacements in a Ba(Fe1-xCox)2As2 superconductor.

    Science.gov (United States)

    Hacisalihoglu, M Y; Paris, E; Joseph, B; Simonelli, L; Sato, T J; Mizokawa, T; Saini, N L

    2016-03-23

    We have studied the local structure of a Ba(Fe1-xCox)2As2 superconductor using temperature dependent extended X-ray absorption fine structure (EXAFS) measurements. Polarized EXAFS at the Fe K-edge on an optimally doped (x = 0.06) single crystal has permitted us to determine atomic displacements across the superconducting transition temperature (Tc). The Fe-As bondlength hardly shows any change with temperature; however, the Fe-Fe sublattice reveals a sharp anomaly across Tc, indicated by a significant drop in mean square relative displacements, similar to the one known for cuprates and A15-type superconductors. We have also found a large atomic disorder around the substituted Co, revealed by polarized Co K-edge EXAFS measurements. The Co-Fe/Co bonds are more flexible than the Fe-Fe bonds with the As-height in Co-containing tetrahedra being larger than the one in FeAs4. The results suggest that the local Fe-Fe bondlength fluctuations and the atomic disorder in this sub-lattice should have some important role in the superconductivity of Ba(Fe1-xCox)2As2 pnictides. PMID:26966734

  13. Long-time dynamics of Kirchhoff wave models with strong nonlinear damping

    CERN Document Server

    Chueshov, Igor

    2010-01-01

    We study well-posedness and long-time dynamics of a class of quasilinear wave equations with a strong damping. We accept the Kirchhoff hypotheses and assume that the stiffness and damping coefficients are $C^1$ functions of the $L_2$-norm of the gradient of the displacement. We first prove the existence and uniqueness of weak solutions and study their properties for a rather wide class of nonlinearities which covers the case of possible degeneration of the stiffness coefficient and the case of a supercritical source term. Our main results deal with global attractors. We prove that in the natural energy space endowed with semistrong topology (strong convergence in displacements, weak -- in velocities) there exists a global attractor whose fractal dimension is finite in some extended space. In the non-supercritical case the result can be improved. In particular, in this case the finite dimensional attractor exists in the strong topology of the energy space. Moreover, in this case we also establish the existence...

  14. Atomic displacements effects on the electronic properties of Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}

    Energy Technology Data Exchange (ETDEWEB)

    Camargo M, J. A. [Fundacion Universitaria Internacional del Tropico Americano, Grupo de Investigacion en Ciencias Basicas, Aplicacion e Innovacion, Carrera 19 No. 39-40, Yopal, Yopal (Colombia); Espitia, D.; Baquero, R., E-mail: jcamargo@unitropico.edu.co [Instituto Politecnico Nacional, Centro de Investigacion y de Estudios Avanzados, Departamento de Fisica, Av. IPN 2508, 07360 Mexico D. F. (Mexico)

    2015-07-01

    The displacements effects of the oxygen atom associated to the Sr-plane (O3) in the electronic properties of Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} (Bi-2223), have been investigated using density functional theory. We determined intervals of the O3 atomic positions for which the band structure calculations show that the Bi-O bands, around the high symmetry point M in the irreducible Brillouin zone, emerge towards higher energies avoiding its contribution at Fermi level, as experimentally has been reported. This procedure does not introduce foreign doping elements into the calculation. Our calculations present a good agreement with the angle-resolved photoemission spectroscopy and nuclear magnetic resonance (NMR) experiments. The two options found differ in character (metallic or nonmetallic) of the Bi-O plane. The are not any experiments, to the best of our knowledge, which determine this character for Bi-2223. (Author)

  15. A new representation of the Kirchhoff's diffraction integral

    Science.gov (United States)

    Ziya Umul, Yusuf

    2013-03-01

    The diffraction integral of Kirchhoff is rearranged according to its integral boundaries. The new approach is based on the theory of the edge dislocation waves and provides a more correct field representation for the semi-infinite and infinite integrals in the direct numerical computation. The integral is studied on the diffraction problem of plane waves by a perfectly conducting half-plane. The correctness of the scattering diagrams is compared with the classical approach and the Fresnel integral representation of the scattered waves numerically.

  16. Instability Paths in the Kirchhoff-Plateau Problem

    Science.gov (United States)

    Giusteri, Giulio G.; Franceschini, Paolo; Fried, Eliot

    2016-04-01

    The Kirchhoff-Plateau problem concerns the equilibrium shapes of a system in which a flexible filament in the form of a closed loop is spanned by a soap film, with the filament being modeled as a Kirchhoff rod and the action of the spanning surface being solely due to surface tension. Adopting a variational approach, we define an energy associated with shape deformations of the system and then derive general equilibrium and (linear) stability conditions by considering the first and second variations of the energy functional. We analyze in detail the transition to instability of flat circular configurations, which are ground states for the system in the absence of surface tension, when the latter is progressively increased. Such a theoretical study is particularly useful here, since the many different perturbations that can lead to instability make it challenging to perform an exhaustive experimental investigation. We generalize previous results, since we allow the filament to possess a curved intrinsic shape and also to display anisotropic flexural properties (as happens when the cross section of the filament is noncircular). This is accomplished by using a rod energy which is familiar from the modeling of DNA filaments. We find that the presence of intrinsic curvature is necessary to obtain a first buckling mode which is not purely tangent to the spanning surface. We also elucidate the role of twisting buckling modes, which become relevant in the presence of flexural anisotropy.

  17. Job Displacement

    OpenAIRE

    Lori G. Kletzer

    1998-01-01

    The past decade and a half has seen tremendous research growth in the area of job displacement. This paper discusses the state of knowledge on the issues and questions of job loss. The 1984-96 Displaced Worker Surveys are used to describe how the characteristics of displacement are changing to include more college educated, white collar, and nonmanufacturing workers. For many workers, the long-term earnings losses following displacement are large due to the loss of firm-specific human capital...

  18. Displacement cascades in polyatomic materials

    Energy Technology Data Exchange (ETDEWEB)

    Parkin, D.M.; Coulter, C.A.

    1982-01-01

    Using a continuous-slowing-down, random amorphous material model, we have studied displacement cascades in a number of diatomic materials. This paper reviews a number of previous results that elucidate the effects of atomic mass, recoil energy, displacement energy, capture energy and material stoichiometry on the numbers of displacements in a cascade. The displacement cascade reveals a complex structure that is dependent on the type of irradiation and the material properties. Conclusions related to damage analysis for fusion reactors are given.

  19. Regularized plane-wave least-squares Kirchhoff migration

    KAUST Repository

    Wang, Xin

    2013-09-22

    A Kirchhoff least-squares migration (LSM) is developed in the prestack plane-wave domain to increase the quality of migration images. A regularization term is included that accounts for mispositioning of reflectors due to errors in the velocity model. Both synthetic and field results show that: 1) LSM with a reflectivity model common for all the plane-wave gathers provides the best image when the migration velocity model is accurate, but it is more sensitive to the velocity errors, 2) the regularized plane-wave LSM is more robust in the presence of velocity errors, and 3) LSM achieves both computational and IO saving by plane-wave encoding compared to shot-domain LSM for the models tested.

  20. Stroh-like formalism for Kirchhoff anisotropic thermoelastic plates

    Directory of Open Access Journals (Sweden)

    Wang Xu

    2013-01-01

    Full Text Available A Stroh-like formalism is developed for the heat conduction and the coupled stretching and bending deformations of a laminated anisotropic thermoelastic thin plate based on Kirchhoff theory. For the heat conduction problem, a Stroh-like quartic formalism is developed. Twodimensional generalized temperature and heat flux function vectors are introduced. The structure of the introduced 4x4 fundamental plate matrix for heat conduction is the same as that of the 8x8 fundamental elasticity matrix in the Stroh sextic formalism for generalized plane strain elasticity. Consequently, the orthogonality and closure relations for heat conduction in thin plates is established. For the thermoelastic problem, an inhomogeneous particular solution is derived rigorously. We obtain an octet formalism in which the general solution is composed of the well-known homogeneous solution developed by Cheng and Reddy (isothermal case and the inhomogeneous particular solution arising from the thermal effect.

  1. Kirchhoff diffraction optics and the nascent Aharonov-Bohm effect: a theorem

    International Nuclear Information System (INIS)

    Textbook diffraction optics, Kirchhoff diffraction, is connected to the Aharonov-Bohm effect of quantum mechanics by an easy theorem proved here. The connection is between the Kirchhoff wave field and the Aharonov-Bohm quantum wave field in the limit of zero flux: the 'nascent' Aharonov-Bohm effect. The diffracting opaque screen of Kirchhoff optics is replaced in the quantum mechanics by a magnetic flux line, or loop, in the shape of the boundary edge of the screen. The gauge must be chosen appropriately: a delta function on that surface, spanning the boundary edge, which matches the screen.

  2. Static Kirchhoff Rods under the Action of External Forces: Integration via Runge-Kutta Method

    Directory of Open Access Journals (Sweden)

    Ademir L. Xavier Jr.

    2014-01-01

    at once Kirchhoff and filament reference system equations under appropriate initial boundary conditions. To show the application of the method, we display several numerical solutions for filaments including cases showing the effect of gravity.

  3. Compressed-sensing application - Pre-stack kirchhoff migration

    KAUST Repository

    Aldawood, Ali

    2013-01-01

    Least-squares migration is a linearized form of waveform inversion that aims to enhance the spatial resolution of the subsurface reflectivity distribution and reduce the migration artifacts due to limited recording aperture, coarse sampling of sources and receivers, and low subsurface illumination. Least-squares migration, however, due to the nature of its minimization process, tends to produce smoothed and dispersed versions of the reflectivity of the subsurface. Assuming that the subsurface reflectivity distribution is sparse, we propose the addition of a non-quadratic L1-norm penalty term on the model space in the objective function. This aims to preserve the sparse nature of the subsurface reflectivity series and enhance resolution. We further use a compressed-sensing algorithm to solve the linear system, which utilizes the sparsity assumption to produce highly resolved migrated images. Thus, the Kirchhoff migration implementation is formulated as a Basis Pursuit denoise (BPDN) problem to obtain the sparse reflectivity model. Applications on synthetic data show that reflectivity models obtained using this compressed-sensing algorithm are highly accurate with optimal resolution.

  4. The possibilities of compressed-sensing-based Kirchhoff prestack migration

    KAUST Repository

    Aldawood, Ali

    2014-05-08

    An approximate subsurface reflectivity distribution of the earth is usually obtained through the migration process. However, conventional migration algorithms, including those based on the least-squares approach, yield structure descriptions that are slightly smeared and of low resolution caused by the common migration artifacts due to limited aperture, coarse sampling, band-limited source, and low subsurface illumination. To alleviate this problem, we use the fact that minimizing the L1-norm of a signal promotes its sparsity. Thus, we formulated the Kirchhoff migration problem as a compressed-sensing (CS) basis pursuit denoise problem to solve for highly focused migrated images compared with those obtained by standard and least-squares migration algorithms. The results of various subsurface reflectivity models revealed that solutions computed using the CS based migration provide a more accurate subsurface reflectivity location and amplitude. We applied the CS algorithm to image synthetic data from a fault model using dense and sparse acquisition geometries. Our results suggest that the proposed approach may still provide highly resolved images with a relatively small number of measurements. We also evaluated the robustness of the basis pursuit denoise algorithm in the presence of Gaussian random observational noise and in the case of imaging the recorded data with inaccurate migration velocities.

  5. Efficient traveltime compression for 3D prestack Kirchhoff migration

    KAUST Repository

    Alkhalifah, Tariq

    2010-12-13

    Kirchhoff 3D prestack migration, as part of its execution, usually requires repeated access to a large traveltime table data base. Access to this data base implies either a memory intensive or I/O bounded solution to the storage problem. Proper compression of the traveltime table allows efficient 3D prestack migration without relying on the usually slow access to the computer hard drive. Such compression also allows for faster access to desirable parts of the traveltime table. Compression is applied to the traveltime field for each source location on the surface on a regular grid using 3D Chebyshev polynomial or cosine transforms of the traveltime field represented in the spherical coordinates or the Celerity domain. We obtain practical compression levels up to and exceeding 20 to 1. In fact, because of the smaller size traveltime table, we obtain exceptional traveltime extraction speed during migration that exceeds conventional methods. Additional features of the compression include better interpolation of traveltime tables and more stable estimates of amplitudes from traveltime curvatures. Further compression is achieved using bit encoding, by representing compression parameters values with fewer bits. © 2010 European Association of Geoscientists & Engineers.

  6. 3D plane-wave least-squares Kirchhoff migration

    KAUST Repository

    Wang, Xin

    2014-08-05

    A three dimensional least-squares Kirchhoff migration (LSM) is developed in the prestack plane-wave domain to increase the quality of migration images and the computational efficiency. Due to the limitation of current 3D marine acquisition geometries, a cylindrical-wave encoding is adopted for the narrow azimuth streamer data. To account for the mispositioning of reflectors due to errors in the velocity model, a regularized LSM is devised so that each plane-wave or cylindrical-wave gather gives rise to an individual migration image, and a regularization term is included to encourage the similarities between the migration images of similar encoding schemes. Both synthetic and field results show that: 1) plane-wave or cylindrical-wave encoding LSM can achieve both computational and IO saving, compared to shot-domain LSM, however, plane-wave LSM is still about 5 times more expensive than plane-wave migration; 2) the regularized LSM is more robust compared to LSM with one reflectivity model common for all the plane-wave or cylindrical-wave gathers.

  7. Fresnel-Kirchhoff theory applied to terrain diffraction problems

    Science.gov (United States)

    Whitteker, J. H.

    1990-09-01

    Fresnel-Kirchhoff theory is adapted to the problem of finding the diffraction attenuation at VHF and UHF over terrain profiles of arbitrary shape. Approximations are based on the assumptions of small wavelength and small diffraction angles. As a preliminary step, the theory is applied to the multiple-knife-edge problem. The field is found as a function of height above each knife edge in turn. In an application of Huygens' principle, an integration over the field above one knife edge provides the field at any point above the next. This formulation is equivalent to knife-edge formulations used in the past. Then each pair of neighboring knife edges is bridged with an imperfectly reflecting plane surface, representing the terrain. Huygens' principle is used again for the reflected wave, neglecting backscatter. The field found in this way is accurate for a good reflector but not a poor one. An analytical comparison shows agreement with rigorous diffraction theory for the problem of a plane wave incident on a perfectly reflecting wedge. Numerical comparisons with rigorous diffraction theory for a spherical Earth and for a small-radius hill (approximated with linear segments) show agreement to within 1.5 dB for the parameters chosen.

  8. Consistent tangent operator for an exact Kirchhoff rod model

    Science.gov (United States)

    Greco, L.; Cuomo, M.

    2015-09-01

    In the paper, it is considered an exact spatial Kirchhoff rod structural model. The configuration space for this model that has dimension 4 is obtained considering an ad hoc split of the rotation operator that implicitly enforces the constraints on the directors. The tangent stiffness operator, essential for the nonlinear numerical simulations, has been studied. It has been obtained as second covariant gradient of the internal energy functional for the considered structural model that preserves symmetry for any configuration, either equilibrated or not. The result has been reached evaluating the Levi- Civita connection for the tangent space of the configuration manifold. The results obtained extend to the case of Kirchoff - Love rods those presented by Simo (Comput Methods Appl Mech Eng 49:55-70, 1985) for Timoshenko rods. Given the different structure of the tangent spaces in this case, it has been necessary to introduce a specific metric that accounts for the rotation of the intrinsic triad due to the change of the position of the centroid axis of the rod.

  9. Atoms

    Institute of Scientific and Technical Information of China (English)

    刘洪毓

    2007-01-01

    Atoms(原子)are all around us.They are something like the bricks (砖块)of which everything is made. The size of an atom is very,very small.In just one grain of salt are held millions of atoms. Atoms are very important.The way one object acts depends on what

  10. Long term simulation of point defect cluster size distributions from atomic displacement cascades in Fe{sub 70}Cr{sub 20}Ni{sub 10}

    Energy Technology Data Exchange (ETDEWEB)

    Souidi, A., E-mail: aek_souidi@yahoo.fr [Université Dr. Tahar Moulay de Saida, Faculté des Sciences, Département de physique, En-nasr BP138, Saida 20000 (Algeria); Hou, M. [Université Libre de Bruxelles, Faculté des Sciences, CP 223, Bd du Triomphe, B-1050 Bruxelles (Belgium); Becquart, C.S. [Unité Matériaux et Transformations (UMET), UMR 8207 Université Lille-1, F-59655 Villeneuve d’Ascq Cédex (France); Domain, C. [EDF-R& D Département MMC, Les renardières, F-77818 Moret sur Loing Cédex (France); De Backer, A. [CCFE, Culham Centre for Fusion Energy, Abingdon (United Kingdom)

    2015-06-01

    We have used an Object Kinetic Monte Carlo (OKMC) model to simulate the long term evolution of the primary damage in Fe{sub 70}Cr{sub 20}Ni{sub 10} alloys. The mean number of Frenkel pairs created by different Primary Knocked on Atoms (PKA) was estimated by Molecular Dynamics using a ternary EAM potential developed in the framework of the PERFORM-60 European project. This number was then used to obtain the vacancy–interstitial recombination distance required in the calculation of displacement cascades in the Binary Collision Approximation (BCA) with code MARLOWE (Robinson, 1989). The BCA cascades have been generated in the 10–100 keV range with the MARLOWE code and two different screened Coulomb potentials, namely, the Molière approximation to the Thomas–Fermi potential and the so-called “Universal” potential by Ziegler, Biersack and Littmark (ZBL). These cascades have been used as input to the OKMC code LAKIMOCA (Domain et al., 2004), with a set of parameters for describing the mobility of point defect clusters based on ab initio calculations and experimental data. The cluster size distributions have been estimated for irradiation doses of 0.1 and 1 dpa, and a dose rate of 10{sup −7} dpa/s at 600 K. We demonstrate that, like in the case of BCC iron, cluster size distributions in the long term are independent of the cascade energy and that the recursive cascade model suggested for BCC iron in Souidi et al. (2011) also applies to FCC Fe{sub 70}Cr{sub 20}Ni{sub 10.} The results also show that the influence of the BCA potential is sizeable but the qualitative correspondence in the predicted long term evolution is excellent.

  11. Atoms

    International Nuclear Information System (INIS)

    Completed by recent contributions on various topics (atoms and the Brownian motion, the career of Jean Perrin, the evolution of atomic physics since Jean Perrin, relationship between scientific atomism and philosophical atomism), this book is a reprint of a book published at the beginning of the twentieth century in which the author addressed the relationship between atomic theory and chemistry (molecules, atoms, the Avogadro hypothesis, molecule structures, solutes, upper limits of molecular quantities), molecular agitation (molecule velocity, molecule rotation or vibration, molecular free range), the Brownian motion and emulsions (history and general features, statistical equilibrium of emulsions), the laws of the Brownian motion (Einstein's theory, experimental control), fluctuations (the theory of Smoluchowski), light and quanta (black body, extension of quantum theory), the electricity atom, the atom genesis and destruction (transmutations, atom counting)

  12. Duality in Geometric Graphs: Vector Graphs, Kirchhoff Graphs and Maxwell Reciprocal Figures

    Directory of Open Access Journals (Sweden)

    Tyler Reese

    2016-02-01

    Full Text Available We compare two mathematical theories that address duality between cycles and vertex-cuts of graphs in geometric settings. First, we propose a rigorous definition of a new type of graph, vector graphs. The special case of R2-vector graphs matches the intuitive notion of drawing graphs with edges taken as vectors. This leads to a discussion of Kirchhoff graphs, as originally presented by Fehribach, which can be defined independent of any matrix relations. In particular, we present simple cases in which vector graphs are guaranteed to be Kirchhoff or non-Kirchhoff. Next, we review Maxwell’s method of drawing reciprocal figures as he presented in 1864, using modern mathematical language. We then demonstrate cases in which R2-vector graphs defined from Maxwell reciprocals are “dual” Kirchhoff graphs. Given an example in which Maxwell’s theories are not sufficient to define vector graphs, we begin to explore other methods of developing dual Kirchhoff graphs.

  13. Simulation of Jet Noise with OVERFLOW CFD Code and Kirchhoff Surface Integral

    Science.gov (United States)

    Kandula, M.; Caimi, R.; Voska, N. (Technical Monitor)

    2002-01-01

    An acoustic prediction capability for supersonic axisymmetric jets was developed on the basis of OVERFLOW Navier-Stokes CFD (Computational Fluid Dynamics) code of NASA Langley Research Center. Reynolds-averaged turbulent stresses in the flow field are modeled with the aid of Spalart-Allmaras one-equation turbulence model. Appropriate acoustic and outflow boundary conditions were implemented to compute time-dependent acoustic pressure in the nonlinear source-field. Based on the specification of acoustic pressure, its temporal and normal derivatives on the Kirchhoff surface, the near-field and the far-field sound pressure levels are computed via Kirchhoff surface integral, with the Kirchhoff surface chosen to enclose the nonlinear sound source region described by the CFD code. The methods are validated by a comparison of the predictions of sound pressure levels with the available data for an axisymmetric turbulent supersonic (Mach 2) perfectly expanded jet.

  14. Displacing use

    DEFF Research Database (Denmark)

    Kelly, Janet; Matthews, Ben

    2014-01-01

    This paper critically discusses the concept of use in design, suggesting that relevant relationships other than use are sometimes obscured by the usercentredness of design processes. We present a design case from the medical device domain that displaced the concept of use from the centre of a hum...

  15. Displacement Ventilation

    DEFF Research Database (Denmark)

    Bjørn, Erik; Mattsson, Magnus; Sandberg, Mats;

    Full-scale experiments were made in a displacement ventilated room with two breathing thermal manikins to study the effect of movements and breathing on the vertical contaminant distribution, and on the personal exposure of occupants. Concentrations were measured with tracer gas equipment in the...

  16. A Step in the D'' Shear Velocity Discontinuity Beneath the Cocos Plate Imaged by Kirchhoff Migration

    Science.gov (United States)

    Hutko, A.; Lay, T.; Garnero, E.; Revenaugh, J.

    2005-12-01

    We use 270 horizontally-polarized S waves from 15 deep earthquakes under South America recorded at broadband stations in western North America to image shear-velocity structure in the deep mantle beneath the Cocos Plate. We use a Kirchhoff migration approach, assuming isotropic scattering from a three-dimensional grid of possible scattering nodes in the lowermost mantle. Several 3D mantle tomography models are used to correct for first-order travel-time perturbations due to volumetric heterogeneity, and waveforms are migrated with respect to either S or ScS arrivals. We observe an East-West striking abrupt 50-150 km change in the depth of the D'' shear velocity discontinuity near 6°N. This feature is apparent in migrations for a 1D reference model and in migrations that use different 3D aspherical models to account for volumetric velocity effects. Our results do not contain significant topography elsewhere on the boundary, and are compatible with a relatively flat D'' discontinuity on either side of the step. The vertical step is constrained to occur over less than 100 km laterally. The step may be due to strong temperature and or chemical gradients, both of which require an active dynamical process to sustain such a steep feature. One dynamical process that can account for the step is folding and piling of a cold slab that has reached the core-mantle boundary, as observed in numerical and experimental models, resulting in a 100 km elevation of the post-perovskite phase boundary due to a 700K lateral temperature reduction in the folded slab. We also detect localized low velocities along the boundary of the imaged D'' discontinuity, which may involve upwellings caused by the slab laterally displacing a thin hot thermal boundary layer. Preliminary efforts to migrate broadband and short period P wave data also reveal complicated D'' structure in this region, however these results are much lower resolution and will be explored in greater detail.

  17. Bilinear spatial control of the velocity term in a Kirchhoff plate equation

    Directory of Open Access Journals (Sweden)

    Mary Elizabeth Bradley

    2001-05-01

    Full Text Available We consider a bilinear optimal control problem with the state equation being a Kirchhoff plate equation. The control is a function of the spatial variables and acts as a multiplier of the velocity term. The unique optimal control, driving the state solution close to a desired evolution function, is characterized in terms of the solution of the optimality system.

  18. Doubly asymptotic trajectories of Lagrangian systems and a problem by Kirchhoff

    International Nuclear Information System (INIS)

    They consider Lagrangian systems with Lagrange functions which exhibit a quadratic time dependence. They prove the existence of infinitely many solutions tending, as t → ± ∞, to an 'equilibrium at infinity'. This result is applied to the Kirchhoff problem of a heavy rigid body moving through a boundless incompressible ideal fluid, which is at rest at infinity and has zero vorticity

  19. Energy Decaying and Blow-Up of Solution for a Kirchhoff Equation with Strong Damping

    Institute of Scientific and Technical Information of China (English)

    YANG Zhifeng; QIU Dehua

    2009-01-01

    The initial boundary value problem for a Kirchhoff equation with Lipschitz type continuous coefficient is studied on bounded domain. Under some conditions, the energy decaying and blow-up of solution are discussed. By refining method, the exponent decay estimates of the energy function and the estimates of the life span of blow-up solutions are given.

  20. GENERAL DECAY OF A TRANSMISSION PROBLEM FOR KIRCHHOFF TYPE WAVE EQUATIONS WITH BOUNDARY MEMORY CONDITION

    Institute of Scientific and Technical Information of China (English)

    Sun Hye PARK

    2014-01-01

    In this paper, we investigate the influence of boundary dissipation on the de-cay property of solutions for a transmission problem of Kirchhoff type wave equation with boundary memory condition. By introducing suitable energy and Lyapunov functionals, we establish a general decay estimate for the energy, which depends on the behavior of relaxation function.

  1. A Fast Method of Deriving the Kirchhoff Formula for Moving Surfaces

    Science.gov (United States)

    Farassat, F.; Posey, Joe W.

    2007-01-01

    The Kirchhoff formula for a moving surface is very useful in many wave propagation problems, particularly in the prediction of noise from rotating machinery. Several publications in the last two decades have presented derivations of the Kirchhoff formula for moving surfaces in both time and frequency domains. Here we present a method originally developed by Farassat and Myers in time domain that is both simple and direct. It is based on generalized function theory and the useful concept of imbedding the problem in the unbounded three-dimensional space. We derive an inhomogeneous wave equation with the source terms that involve Dirac delta functions with their supports on the moving data surface. This wave equation is then solved using the simple free space Green's function of the wave equation resulting in the Kirchhoff formula. The algebraic manipulations are minimal and simple. We do not need the Green's theorem in four dimensions and there is no ambiguity in the interpretation of any terms in the final formulas. Furthermore, this method also gives the simplest derivation of the classical Kirchhoff formula which has a fairly lengthy derivation in physics and applied mathematics books. The Farassat-Myers method can be used easily in frequency domain.

  2. Digital displacements

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2014-01-01

    digital reforms in Denmark and shows how citizen service is transformed from service to support. The frontline employee’s classical tasks such as casework are being displaced into educational and support-oriented tasks with less professional content. Thus an unintended effect of digitisation is blurred......In recent years digital reforms are being introduced in the municipal landscape of Denmark. The reforms address the interaction between citizen and local authority. The aim is, that by 2015 at least 80 per cent of all correspondence between citizens and public authority will be transmitted through...... digital interface. However, the transformation of citizen services from traditional face-to-face interaction to digital self-service gives rise to new practices; some citizens need support to be able to manage self-service through digital tools. A mixture of support and teaching, named co...

  3. Irradiation-induced displacement of Ag atoms from lattice sites in an Al-0.2% Mg-0.1% Ag crystal

    International Nuclear Information System (INIS)

    In irradiated alloys of Al containing approximately 0.1 at% Ag, the backscattering - channelling method shows that Al-Ag dumbells are created by the trapping of Al interstitial atoms at Ag solute atoms. The present results demonstrate that the addition of 0.2 at% Mg to such irradiated alloys retards not only the formation of Al-Ag dumbells during annealing from 30 to 100 K but also their annihilation during annealing from 180 to 240 K. Al interstitials are released from Mg traps at 100 to 160 K, causing further trapping at Ag atoms. Approximately 70% of the Ag atoms return to lattice sites at approximately 200 K (stage III) (compared with 100% in the Al-0.1% Ag alloys) and the remainder return to lattice sites at approximately 260 K. These results favour migration of Al-Ag dumbells rather than vacancies during stage III annealing. (author)

  4. Thermal radiation of Er doped dielectric crystals: Probing the range of applicability of the Kirchhoff law

    CERN Document Server

    Tanyi, Ekembu K; Narimanov, Evgenii E; Noginov, M A

    2016-01-01

    The Kirchhoff law of thermal radiation, relating emissivity {\\epsilon} and absorptance {\\alpha}, has been originally formulated for opaque bodies in thermodynamic equilibrium with the environment. However, in many systems of practical importance, both assumptions are often not satisfied. In this work, we revisit the century-old law and examine the limits of its applicability in an example of Er:YAG and Er:YLF dielectric crystals, potential radiation converters for thermophotovoltaic applications. In our experiments, the (80 at.%) Er:YAG crystal was opaque between 1.45 {\\mu}m and 1.64 {\\mu}m. In this spectral range, its absorptance {\\alpha}({\\lambda}) is spectrally flat and differentiates from unity only by a small amount of reflection. The shape of the emissivity spectrum {\\epsilon}({\\lambda}) closely matches that of absorptance {\\alpha}({\\lambda}), suggesting that the Kirchhoff law can adequately describe thermal radiation of opaque bodies, even if the requirement of thermodynamic equilibrium is not satisfie...

  5. Noise Properties in the Ideal Kirchhoff-Law-Johnson-Noise Secure Communication System

    OpenAIRE

    Gingl, Zoltan; Mingesz, Robert

    2014-01-01

    In this paper we determine the noise properties needed for unconditional security for the ideal Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system using simple statistical analysis. It has already been shown using physical laws that resistors and Johnson-like noise sources provide unconditional security. However real implementations use artificial noise generators, therefore it is a question if other kind of noise sources and resistor values could be used as well. We answer thi...

  6. EQUIVALENCE BETWEEN EXACT INTERNAL CONTROLLABILITY OF THE KIRCHHOFF PLATE-LIKE EQUATION AND THE WAVE EQUATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    When the rotatory inertia is taken into account, vibrations of a linear plate can be described by the Kirchhoff plate equation. Consider this equation with locally distributed control forces and some boundary condition which is the simply supported boundary condition for a rectangular plate. In this paper, the authors establish exact controllability of the system in terms of the equivalence to exact internal controllability of the wave equation, by means of a frequency domain characterization of exact controllability introduced recently in [11].

  7. Kirchhoff equations from quasi-analytic to spectral-gap data

    OpenAIRE

    Ghisi, Marina; Gobbino, Massimo

    2010-01-01

    In a celebrated paper (Tokyo J. Math. 1984) K. Nishihara proved global existence for Kirchhoff equations in a special class of initial data which lies in between analytic functions and Gevrey spaces. This class was defined in terms of Fourier components with weights satisfying suitable convexity and integrability conditions. In this paper we extend this result by removing the convexity constraint, and by replacing Nishihara's integrability condition with the simpler integrability condition wh...

  8. Calculations of atomic sputtering and displacement cross-sections in solid elements by electrons with energies from threshold to 1.5 MV

    International Nuclear Information System (INIS)

    The kinetics of knock-on collisions of relativistic electrons with nuclei and details of the numerical evaluation of differential, recoil, and total Mott cross-sections are reviewed and discussed. The effects of electron beam induced displacement and sputtering, in the transmission electron microscope (TEM) environment, on microanalysis are analyzed with particular emphasis placed on the removal of material by knock-on sputtering. The mass loss predicted due to transmission knock-on sputtering is significant for many elements under conditions frequently encountered in microanalysis. Total Mott cross-sections are tabulated for all naturally occurring solid elements up to Z = 92 at displacement energies of one, two, four, and five times the sublimation energy and for accelerating voltages accessible in the transmission electron microscope. Fortran source code listings for the calculation of the differential Mott cross-section as a function of electron scattering angle (dMottCS), as a function of nuclear recoil angle (RECOIL), and the total Mott cross-section (TOTCS) are included. 48 refs., 21 figs., 12 tabs

  9. Calculations of atomic sputtering and displacement cross-sections in solid elements by electrons with energies from threshold to 1. 5 MV

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, C.R.

    1988-12-01

    The kinetics of knock-on collisions of relativistic electrons with nuclei and details of the numerical evaluation of differential, recoil, and total Mott cross-sections are reviewed and discussed. The effects of electron beam induced displacement and sputtering, in the transmission electron microscope (TEM) environment, on microanalysis are analyzed with particular emphasis placed on the removal of material by knock-on sputtering. The mass loss predicted due to transmission knock-on sputtering is significant for many elements under conditions frequently encountered in microanalysis. Total Mott cross-sections are tabulated for all naturally occurring solid elements up to Z = 92 at displacement energies of one, two, four, and five times the sublimation energy and for accelerating voltages accessible in the transmission electron microscope. Fortran source code listings for the calculation of the differential Mott cross-section as a function of electron scattering angle (dMottCS), as a function of nuclear recoil angle (RECOIL), and the total Mott cross-section (TOTCS) are included. 48 refs., 21 figs., 12 tabs.

  10. A robust and real-time vascular intervention simulation based on Kirchhoff elastic rod.

    Science.gov (United States)

    Luo, Maisheng; Xie, Hongzhi; Xie, Le; Cai, Ping; Gu, Lixu

    2014-12-01

    A virtual reality (VR) based vascular intervention simulation system is introduced in this paper, which helps trainees develop surgical skills and experience complications in safety remote from patients. The system simulates interventional radiology procedures, in which flexible tipped guidewires are employed to advance diagnostic or therapeutic catheters into vascular anatomy of a patient. A real-time physically-based modeling approach ground on Kirchhoff elastic rod is proposed to simulate complicated behaviors of guidewires and catheters. The slender body of guidewire and catheter is modeled using more efficient special case of naturally straight, isotropic Kirchhoff rods, and the shorter flexible tip composed of straight or angled design is modeled using more complex generalized Kirchhoff rods. The motion equations for guidewire and catheter were derived with continuous elastic energy, followed by a discretization using a linear implicit scheme that guarantees stability and robustness. In addition, we used a fast-projection method to enforce the inextensibility of guidewire and catheter. An adaptive sampling algorithm was also implemented to improve the simulation efficiency without decrease of accuracy. Experimental results revealed that our system is both robust and efficient in a real-time performance. PMID:25223506

  11. Theoretical tools for atom laser beam propagation

    OpenAIRE

    Riou, J. -F.; Coq, Y. Le; Impens, F; Guerin, W.; Bordé, C. J.; Aspect, A; Bouyer, P.

    2008-01-01

    We present a theoretical model for the propagation of non self-interacting atom laser beams. We start from a general propagation integral equation, and we use the same approximations as in photon optics to derive tools to calculate the atom laser beam propagation. We discuss the approximations that allow to reduce the general equation whether to a Fresnel-Kirchhoff integral calculated by using the stationary phase method, or to the eikonal. Within the paraxial approximation, we also introduce...

  12. On Classical Dynamics of Affinely-Rigid Bodies Subject to the Kirchhoff-Love Constraints

    Directory of Open Access Journals (Sweden)

    Vasyl Kovalchuk

    2010-04-01

    Full Text Available In this article we consider the affinely-rigid body moving in the three-dimensional physical space and subject to the Kirchhoff-Love constraints, i.e., while it deforms homogeneously in the two-dimensional central plane of the body it simultaneously performs one-dimensional oscillations orthogonal to this central plane. For the polar decomposition we obtain the stationary ellipsoids as special solutions of the general, strongly nonlinear equations of motion. It is also shown that these solutions are conceptually different from those obtained earlier for the two-polar (singular value decomposition.

  13. Global Nonexistence of Solutions for Viscoelastic Wave Equations of Kirchhoff Type with High Energy

    Directory of Open Access Journals (Sweden)

    Gang Li

    2012-01-01

    Full Text Available We consider viscoelastic wave equations of the Kirchhoff type utt-M(∥∇u∥22Δu+∫0tg(t-sΔu(sds+ut=|u|p-1u with Dirichlet boundary conditions, where ∥⋅∥p denotes the norm in the Lebesgue space Lp. Under some suitable assumptions on g and the initial data, we establish a global nonexistence result for certain solutions with arbitrarily high energy, in the sense that lim⁡t→T*-(∥u(t∥22+∫0t∥u(s∥22ds=∞ for some 0

  14. Generalized Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system using arbitrary resistors

    CERN Document Server

    Vadai, Gergely; Gingl, Zoltan

    2015-01-01

    The Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system has been introduced as a simple, very low cost and efficient classical physical alternative to quantum key distribution systems. The ideal system uses only a few electronic components - identical resistor pairs, switches and interconnecting wires - to guarantee perfectly protected data transmission. We show that a generalized KLJN system can provide unconditional security even if it is used with significantly less limitations. The more universal conditions ease practical realizations considerably and support more robust protection against attacks. Our theoretical results are confirmed by numerical simulations.

  15. Twist and Stretch of Helices Explained via the Kirchhoff-Love Rod Model of Elastic Filaments

    KAUST Repository

    Đuričković, Bojan

    2013-09-05

    In various single-molecule experiments, a chiral polymer, such as DNA, is simultaneously pulled and twisted. We address an elementary but fundamental question raised by various authors: does the molecule overwind or unwind under tension? We show that within the context of the classic Kirchhoff-Love rod model of elastic filaments, both behaviors are possible, depending on the precise constitutive relations of the polymer. More generally, our analysis provides an effective linear response theory for helical structures that relates axial force and axial torque to axial translation and rotation. © 2013 American Physical Society.

  16. Job Displacement and Crime

    DEFF Research Database (Denmark)

    Bennett, Patrick; Ouazad, Amine

    We use a detailed employer-employee data set matched with detailed crime information (timing of crime, fines, convictions, crime type) to estimate the impact of job loss on an individual's probability to commit crime. We focus on job losses due to displacement, i.e. job losses in firms losing a...... that displaced workers' propensity to commit crime is higher than non-displaced workers before the displacement event; but it is significantly higher afterwards. Displacement impacts crime over and above what is explained by earnings losses and weeks of unemployment following displacement....

  17. Comparison of microfacet BRDF model to modified Beckmann-Kirchhoff BRDF model for rough and smooth surfaces.

    Science.gov (United States)

    Butler, Samuel D; Nauyoks, Stephen E; Marciniak, Michael A

    2015-11-01

    A popular class of BRDF models is the microfacet models, where geometric optics is assumed. In contrast, more complex physical optics models may more accurately predict the BRDF, but the calculation is more resource intensive. These seemingly disparate approaches are compared in detail for the rough and smooth surface approximations of the modified Beckmann-Kirchhoff BRDF model, assuming Gaussian surface statistics. An approximation relating standard Fresnel reflection with the semi-rough surface polarization term, Q, is presented for unpolarized light. For rough surfaces, the angular dependence of direction cosine space is shown to be identical to the angular dependence in the microfacet distribution function. For polished surfaces, the same comparison shows a breakdown in the microfacet models. Similarities and differences between microfacet BRDF models and the modified Beckmann-Kirchhoff model are identified. The rationale for the original Beckmann-Kirchhoff F(bk)(2) geometric term relative to both microfacet models and generalized Harvey-Shack model is presented. A modification to the geometric F(bk)(2) term in original Beckmann-Kirchhoff BRDF theory is proposed. PMID:26561179

  18. Application of the generalized Kirchhoff's law to calculation of photoluminescence spectra of one-dimensional photonic crystals

    CERN Document Server

    Voronov, Mikhail M

    2016-01-01

    The approach based on the generalized Kirchhoff's law for calculating photoluminescence spectra of one-dimensional multi-layered structures, in particular, 1D photonic crystals has been developed. It is valid in the local thermodynamic equilibrium approximation and leads to simple and explicit expressions for the photoluminescence intensity. In the framework of the present theory the Purcell factor has been discussed as well.

  19. An efficient parallel algorithm: Poststack and prestack Kirchhoff 3D depth migration using flexi-depth iterations

    Science.gov (United States)

    Rastogi, Richa; Srivastava, Abhishek; Khonde, Kiran; Sirasala, Kirannmayi M.; Londhe, Ashutosh; Chavhan, Hitesh

    2015-07-01

    This paper presents an efficient parallel 3D Kirchhoff depth migration algorithm suitable for current class of multicore architecture. The fundamental Kirchhoff depth migration algorithm exhibits inherent parallelism however, when it comes to 3D data migration, as the data size increases the resource requirement of the algorithm also increases. This challenges its practical implementation even on current generation high performance computing systems. Therefore a smart parallelization approach is essential to handle 3D data for migration. The most compute intensive part of Kirchhoff depth migration algorithm is the calculation of traveltime tables due to its resource requirements such as memory/storage and I/O. In the current research work, we target this area and develop a competent parallel algorithm for post and prestack 3D Kirchhoff depth migration, using hybrid MPI+OpenMP programming techniques. We introduce a concept of flexi-depth iterations while depth migrating data in parallel imaging space, using optimized traveltime table computations. This concept provides flexibility to the algorithm by migrating data in a number of depth iterations, which depends upon the available node memory and the size of data to be migrated during runtime. Furthermore, it minimizes the requirements of storage, I/O and inter-node communication, thus making it advantageous over the conventional parallelization approaches. The developed parallel algorithm is demonstrated and analysed on Yuva II, a PARAM series of supercomputers. Optimization, performance and scalability experiment results along with the migration outcome show the effectiveness of the parallel algorithm.

  20. Job Displacement and Crime

    DEFF Research Database (Denmark)

    Bennett, Patrick; Ouazad, Amine

    theory of crime. Marital dissolution is more likely post-displacement, and we find small intra-family externalities of adult displacement on younger family members’ crime. The impact of displacement on crime is stronger in municipalities with higher capital and labor income inequalities.......This paper matches a comprehensive Danish employer-employee data set with individual crime information (timing of offenses, charges, convictions, and prison terms by crime type) to estimate the impact of job displacement on an individual’s propensity to commit crime. We focus on displaced...... individuals, i.e. high-tenure workers with strong attachment to their firm, who lose employment during a mass-layoff event. Pre-displacement data suggests no evidence of endogenous selection of workers for displacement during mass-layoffs: displaced workers’ propensity to commit crime exhibits no...

  1. Performance analysis of the “intelligent” Kirchhoff-Law-Johnson-Noise secure key exchange

    Science.gov (United States)

    Smulko, Janusz

    2014-09-01

    The Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system provides a way of exchanging information theoretic secure keys by measuring the random voltage and current through the wire connecting two different resistors at Alice's and Bob's ends. Recently new advanced protocols for the KLJN method have been proposed with enhanced performance. In this paper we analyze the KLJN system and compare with “intelligent” KLJN (iKLJN) scheme. This task requires the determination of the applied resistors and the identification of the various superpositions of known and unknown noise components. Some statistical tools to determine how the duration of the bit exchange window (averaging time) influences the performance of secure bit exchange will be explored.

  2. Local Projection-Based Stabilized Mixed Finite Element Methods for Kirchhoff Plate Bending Problems

    Directory of Open Access Journals (Sweden)

    Xuehai Huang

    2013-01-01

    Full Text Available Based on stress-deflection variational formulation, we propose a family of local projection-based stabilized mixed finite element methods for Kirchhoff plate bending problems. According to the error equations, we obtain the error estimates of the approximation to stress tensor in energy norm. And by duality argument, error estimates of the approximation to deflection in H1-norm are achieved. Then we design an a posteriori error estimator which is closely related to the equilibrium equation, constitutive equation, and nonconformity of the finite element spaces. With the help of Zienkiewicz-Guzmán-Neilan element spaces, we prove the reliability of the a posteriori error estimator. And the efficiency of the a posteriori error estimator is proved by standard bubble function argument.

  3. Kirchhoff's Integral Representation and a Cavity Wake Potential

    Energy Technology Data Exchange (ETDEWEB)

    Novokhatski, Alexander; /SLAC

    2012-02-17

    A method is proposed for the calculation of the short-range wake field potentials of an ultra-relativistic bunch passing near some irregularities in a beam pipe. The method is based on the space-time domain integration of Maxwell's equations using Kirchhoff's formulation. We demonstrate this method on two cases where we obtain the wake potentials for the energy loss of a bunch traversing an iris-collimator in a beam pipe and for a cavity. Likewise, formulas are derived for Green's functions that describe the transverse force action of wake fields. Simple formulas for the total energy loss of a bunch with a Gaussian charge density distribution are derived as well. The derived estimates are compared with computer results and predictions of other models.

  4. Existence of solutions to nonlocal Kirchhoff equations of elliptic type via genus theory

    Directory of Open Access Journals (Sweden)

    Nemat Nyamoradi

    2014-04-01

    Full Text Available In this article, we study the existence and multiplicity of solutions to the nonlocal Kirchhoff fractional equation $$\\displaylines{ \\Big(a + b\\int_{\\mathbb{R}^{2N}} |u (x - u (y|^2 K (x - y\\,dx\\,dy\\Big (- \\Delta^s u - \\lambda u = f (x, u (x \\quad \\text{in } \\Omega,\\cr u = 0 \\quad \\text{in } \\mathbb{R}^N \\setminus \\Omega, }$$ where $a, b > 0$ are constants, $(- \\Delta^s$ is the fractional Laplace operator, $s \\in (0, 1$ is a fixed real number, $\\lambda$ is a real parameter and $\\Omega$ is an open bounded subset of $\\mathbb{R}^N$, $N > 2 s$, with Lipschitz boundary, $f: \\Omega \\times \\mathbb{R} \\to \\mathbb{R}$ is a continuous function. The proofs rely essentially on the genus properties in critical point theory.

  5. Existence of solutions for p-Kirchhoff type problems with critical exponent

    Directory of Open Access Journals (Sweden)

    Ahmed Hamydy

    2011-08-01

    Full Text Available We study the existence of solutions for the p-Kirchhoff type problem involving the critical Sobolev exponent, $$displaylines{ -Big[gBig(int_Omega|abla u|^pdxBigBig]Delta_pu =lambda f(x,u+|u|^{p^star-2}uquadext{in }Omega,cr u=0quadext{on }partialOmega, }$$ where $Omega$ is a bounded smooth domain of $mathbb{R}^N$, $1

  6. Rayleigh-Sommerfield Diffraction vs Fresnel-Kirchhoff, Fourier Propagation and Poisson's Spot

    Science.gov (United States)

    Lucke, Robert L.

    2004-01-01

    The boundary conditions imposed on the diffraction problem in order to obtain the Fresnel-Kirchhoff (FK) solution are well-known to be mathematically inconsistent and to be violated by the solution when the observation point is close to the diffracting screen 1-3. These problems are absent in the Rayleigh-Sommerfeld (RS) solution. The difference between RS and FK is in the inclination factor and is usually immaterial because the inclination factor is approximated by unity. But when this approximation is not valid, FK can lead to unacceptable answers. Calculating the on-axis intensity of Poisson s spot provides a critical test, a test passed by RS and failed by FK. FK fails because (a) convergence of the integral depends on how it is evaluated and (b) when the convergence problem is xed, the predicted amplitude at points near the obscuring disk is not consistent with the assumed boundary conditions.

  7. Simple solution to the Fresnel-Kirchhoff diffraction integral for application to refraction enhanced radiography

    International Nuclear Information System (INIS)

    We present a simple solution to the Fresnel-Kirchhoff diffraction integral that is appropriate for x-ray radiography of strongly absorbing and phase-shifting objects in the geometrical optics regime, where phase contrast enhancements can be considered to be caused by refraction by a semi-opaque object. We demonstrate its accuracy by comparison to brute-force numerical ray trace and diffraction calculations of a representative simulated object, and show excellent agreement for spatial scales corresponding to Fresnel numbers greater than unity. The result represents a significant improvement over approximate formulas typically used in analysis of refraction-enhanced radiographs, particularly for radiography of transient phenomena in objects that strongly refract and show significant absorption. (authors)

  8. Applications of Fresnel-Kirchhoff diffraction integral in linear and nonlinear optics: a didactic introduction

    Science.gov (United States)

    Pilla, V.; Costa, G. G. G.; Catunda, Tomaz

    2001-08-01

    In nonlinear optics, the Gaussian beam intensity profile, I(r) exp(-2r2/w2) generates a refractive index profile (Delta) n(r), and consequently a phase profile. Depending on the magnitude of the phase profile, rings structures can be observed in the beam far field intensity profile, the so-called Transverse Self Phase Modulation effect. In this work, we calculated these rings formation due to thermal and Kerr non linearities, using the Fresnel- Kirchhoff diffraction integral. In the case of Kerr nonlinearity, the refractive index profile is also Gaussian since n(r) equals n0 + n2I(r). However, due to the effect of heat diffusion, in the case of thermal nonlinearity the refractive index profile is broader than I(r).

  9. Beam quality of a non-ideal atom laser

    OpenAIRE

    Riou, Jean-Félix; Guerin, William; Le Coq, Yann; Fauquembergue, Marie; Bouyer, Philippe; Josse, Vincent; Aspect, Alain

    2006-01-01

    International audience We study the propagation of a non-interacting atom laser distorted by the strong lensing effect of the Bose-Einstein Condensate (BEC) from which it is outcoupled. We observe a transverse structure containing caustics that vary with the density within the residing BEC. Using WKB approximation, Fresnel-Kirchhoff integral formalism and ABCD matrices, we are able to describe analytically the atom laser propagation. This allows us to characterize the quality of the non-id...

  10. Theoretical tools for atom-laser-beam propagation

    OpenAIRE

    Riou, Jean-Félix; Le Coq, Yann; Impens, François; Guerin, William; Bordé, Christian,; Aspect, Alain; Bouyer, Philippe

    2008-01-01

    We present a theoretical model for the propagation of non self-interacting atom laser beams. We start from a general propagation integral equation, and we use the same approximations as in photon optics to derive tools to calculate the atom laser beam propagation. We discuss the approximations that allow to reduce the general equation whether to a Fresnel-Kirchhoff integral calculated by using the stationary phase method, or to the eikonal. Within the paraxial approximation, we also introduce...

  11. Research Paradigm of Displaced Aggression

    OpenAIRE

    Tanno, Syota

    2013-01-01

    A review of research paradigm of displaced aggression is presented. The author arranged the Japanese wording of displaced aggression, summarized the historical transition of research on displaced aggression, and reviewed research paradigm of displaced aggression.

  12. Iterative Multiparameter Elastic Waveform Inversion Using Prestack Time Imaging and Kirchhoff approximation

    Science.gov (United States)

    Khaniani, Hassan

    boundary condition of the wave equation is set up along reflection surfaces. Hence, the surface integral Kirchhoff approximation is used as a mathematical framework instead of the volume integral of the Born approximation. In addition, I study the feasibility of iterative coupling of ray theory with the Kirchhoff approximation for inversion. For the amplitude considerations, the direct relationship between the scattering potential of the Born approximation with the reflectivity function of the asymptotic Kirchhoff approximation for elastic waves is used. Therefore, I use the linearized Zoeppritz approximation of Aki and Richards (1980) for computation of the forward modeling and migration operators as well as gradient function from Amplitude vs Offset (AVO) inversion. The multiparameter elastic inversion approach is applicable to all types of reflected wavefields such as P-to-P, P-to-S, S-to-S and S-to-P. Traveltime estimation of forward modeling and migration/inversion operators are based on the DSR equation. All operators involved in inversion, including the background model for DSR and AVO are updated at each iteration. The migration/inversion procedure maps the mode converted waves to the traveltime of incident waves which fixes the registration problem of events that travel from source to scatter point. The inversion of the reflected P-to-P and P-to-S synthetic and field data are provided for the numerical examples. This approach is applicable for complex structures however, to estimate the traveltime of scatterpoints, ray tracing can be added to the algorithm. For such a medium, the scatterpoint traveltime approximations from the PSTM, is compared to the PSDM approach using numerical analysis of ray- and FDTD-based modeling. In part of this thesis, I further improve the conventional velocity analysis of Common Scatter Point (CSP) gathers by including the tilt effects. I show that travel time response of scatter points beneath a dipping interface experiences an

  13. Time-domain flexural wave intensity estimation in orthotropic Kirchhoff plates

    Science.gov (United States)

    Halkyard, C. R.; Masson, P.

    2016-04-01

    In this paper, a method for estimating the vibrational energy flow associated with the flexural vibration of an orthotropic Kirchhoff plate, in the time-domain, is presented. The approach is based on the plane propagating wave solution to the equation of motion, and uses a Fourier series approximation of the wave field. The various linear and angular velocities, shear forces and moments that are needed to calculate the energy flow are estimated by digitally filtering and combining the outputs of an array of sensors. A similar approach is used to reconstruct the local wave field to provide an estimate of the wave propagation direction. The theoretical basis of the approach is described, and design considerations for the sensor array and for the filters used for parameter estimation are discussed. Simulations are presented for plane flexural waves and for transient transverse point force excitation of a range of orthotropic plates having different material properties, using a simulated array of velocity sensors. These simulations show that the method can provide accurate estimates of the magnitude and direction of the vibrational energy flow, as well as of the propagation direction of a single wave train or 'burst', provided that the sensor array is sufficiently distant from the excitation point. This is consistent with preliminary experimental measurements, also presented in this paper, performed on a composite orthotropic plate.

  14. Limited-memory BFGS based least-squares pre-stack Kirchhoff depth migration

    Science.gov (United States)

    Wu, Shaojiang; Wang, Yibo; Zheng, Yikang; Chang, Xu

    2015-08-01

    Least-squares migration (LSM) is a linearized inversion technique for subsurface reflectivity estimation. Compared to conventional migration algorithms, it can improve spatial resolution significantly with a few iterative calculations. There are three key steps in LSM, (1) calculate data residuals between observed data and demigrated data using the inverted reflectivity model; (2) migrate data residuals to form reflectivity gradient and (3) update reflectivity model using optimization methods. In order to obtain an accurate and high-resolution inversion result, the good estimation of inverse Hessian matrix plays a crucial role. However, due to the large size of Hessian matrix, the inverse matrix calculation is always a tough task. The limited-memory BFGS (L-BFGS) method can evaluate the Hessian matrix indirectly using a limited amount of computer memory which only maintains a history of the past m gradients (often m < 10). We combine the L-BFGS method with least-squares pre-stack Kirchhoff depth migration. Then, we validate the introduced approach by the 2-D Marmousi synthetic data set and a 2-D marine data set. The results show that the introduced method can effectively obtain reflectivity model and has a faster convergence rate with two comparison gradient methods. It might be significant for general complex subsurface imaging.

  15. Huygens--Fresnel--Kirchhoff wave-front diffraction formulation: paraxial and exact Gaussian laser beams

    International Nuclear Information System (INIS)

    The Huygens--Fresnel diffraction integral has been formulated for incident Gaussian laser beams by using the Kirchhoff obliquity factor with the wave front instead of the aperture plane as the surface of integration. Accurate numerical-integration calculations were used to investigate the Fresnel field diffraction region for the much-studied case of a circular aperture. It is shown that the classical aperture-plane formulation becomes inaccurate when the wave front, as truncated at the aperture, has any degree of curvature to it, whereas the newly developed wave-front formulation produces accurate results for as much as one aperture diameter behind the aperture plane. The wave-front diffraction integral was developed for both the classical paraxial and the recently developed exact solutions to the scalar wave equation for a Gaussian beam. Detailed comparisons of these two diffraction solutions show that they are essentially identical for the typical laboratory laser. The typical laboratory laser is defined as having a wavelength in the near-infrared-through-visible range, a beam diameter as large as several millimeters, and a beam divergence angle as large as several milliradians

  16. Kirchhoff PSDM angle-gather generation based on the traveltime gradient

    Science.gov (United States)

    Liu, Shao-Yong; Wang, Hua-Zhong; Liu, Tai-Chen; Hu, Ying; Zhang, Cai

    2015-03-01

    Angle-domain common-image gathers (ADCIGs) are the basic data in migration velocity analysis (MVA) and amplitude variation with angle (AVA) analysis. We propose a common-angle gather-generating scheme using Kirchhoff PSDM based on the traveltime gradient field. The scheme includes three major operations: (1) to calculate the traveltime field of the source and the receiver based on the dynamic programming approach; (2) to obtain the reflection angle according to the traveltime gradient field in the image space; and (3) to generate the ADCIGs during the migration process. Because of the computation approach, the method for generating ADCIGs is superior to conventional ray-based methods. We use the proposed ADCIGs generation method in 3D large-scale seismic data. The key points of the method are the following. (1) We use common-shot datasets for migration, (2) we load traveltimes based on the shot aperture, and (3) we use the MPI and OpenMp memory sharing to decrease the amount of input and output (I/O). Numerical examples using synthetic data suggest that the ADCIGs improve the quality of the velocity and the effectiveness of the 3D angle-gather generation scheme.

  17. Diffuse scattered field of elastic waves from randomly rough surfaces using an analytical Kirchhoff theory

    Science.gov (United States)

    Shi, F.; Lowe, M. J. S.; Xi, X.; Craster, R. V.

    2016-07-01

    We develop an elastodynamic theory to predict the diffuse scattered field of elastic waves by randomly rough surfaces, for the first time, with the aid of the Kirchhoff approximation (KA). Analytical expressions are derived incorporating surface statistics, to represent the expectation of the angular distribution of the diffuse intensity for different modes. The analytical solutions are successfully verified with numerical Monte Carlo simulations, and also validated by comparison with experiments. We then apply the theory to quantitatively investigate the effects of the roughness and the shear-to-compressional wave speed ratio on the mode conversion and the scattering intensity, from low to high roughness within the valid region of KA. Both the direct and the mode converted intensities are significantly affected by the roughness, which leads to distinct scattering patterns for different wave modes. The mode conversion effect is very strong around the specular angle and it is found to increase as the surface appears to be more rough. In addition, the 3D roughness induced coupling between the out-of-plane shear horizontal (SH) mode and the in-plane modes is studied. The intensity of the SH mode is shown to be very sensitive to the out-of-plane correlation length, being influenced more by this than by the RMS value of the roughness. However, it is found that the depolarization pattern for the diffuse field is independent of the actual value of the roughness.

  18. Displacement Data Assimilation

    CERN Document Server

    Rosenthal, W Steven; Mariano, Arthur J; Restrepo, Juan M

    2016-01-01

    We show that modifying a Bayesian data assimilation scheme by incorporating kinematically-consistent displacement corrections produces a scheme that is demonstrably better at estimating partially observed state vectors in a setting where feature information important. While the displacement transformation is not tied to any particular assimilation scheme, here we implement it within an ensemble Kalman Filter and demonstrate its effectiveness in tracking stochastically perturbed vortices.

  19. Internal displacement in Burma.

    Science.gov (United States)

    Lanjouw, S; Mortimer, G; Bamforth, V

    2000-09-01

    The internal displacement of populations in Burma is not a new phenomenon. Displacement is caused by numerous factors. Not all of it is due to outright violence, but much is a consequence of misguided social and economic development initiatives. Efforts to consolidate the state by assimilating populations in government-controlled areas by military authorities on the one hand, while brokering cease-fires with non-state actors on the other, has uprooted civilian populations throughout the country. Very few areas in which internally displaced persons (IDPs) are found are not facing social turmoil within a climate of impunity. Humanitarian access to IDP populations remains extremely problematic. While relatively little information has been collected, assistance has been focused on targeting accessible groups. International concern within Burma has couched the problems of displacement within general development modalities, while international attention along its borders has sought to contain displacement. With the exception of several recent initiatives, few approaches have gone beyond assistance and engaged in the prevention or protection of the displaced. PMID:11026156

  20. Green-Naghdi rate of the Kirchhoff stress and deformation rate: the elasticity tensor

    Science.gov (United States)

    Bellini, Chiara; Federico, Salvatore

    2015-06-01

    The elasticity tensor providing the power-conjugation of the Green-Naghdi rate of the Kirchhoff stress and the deformation rate is required, e.g. by the commercially available Finite Element package ABAQUS/Standard for the material user subroutine UMAT, used to input material behaviours other than those included in the libraries of the package. This elasticity tensor had been studied in the literature, but its symmetries have only been briefly discussed, and only its component form in Cartesian coordinates was known. In this work, we derived a covariant, component-free expression of this elasticity tensor and thoroughly studied its symmetries. We found that, although symmetry on both pair of feet (indices) has been deemed to be desirable in the literature, the expression of the tensor available to-date in fact possesses only symmetry on the first pair of feet (indices), whereas the second pair lacks symmetry, and therefore carries a skew-symmetric contribution. This contribution is unnecessary, as it is automatically filtered in the contraction of the elasticity tensor with the symmetric deformation rate tensor. In order to avoid carrying this unnecessary skew-symmetric contribution in the computations, we employ a tensor identity that naturally symmetrises the second pair of feet of the elasticity tensor. We demonstrated the validity and robustness of the implementation of the user-defined material based on this tensor representation by simulating a benchmark problem consisting in biaxial tests of porcine and human atrial tissue, with material properties taken from previously performed experiments. We compared the results obtained by means of our user-defined material and those obtained through an equivalent built-in material, and obtained identical results.

  1. Random-Resistor-Random-Temperature Kirchhoff-Law-Johnson-Noise (RRRT-KLJN Key Exchange

    Directory of Open Access Journals (Sweden)

    Kish Laszlo B.

    2016-03-01

    Full Text Available We introduce two new Kirchhoff-law-Johnson-noise (KLJN secure key distribution schemes which are generalizations of the original KLJN scheme. The first of these, the Random-Resistor (RR- KLJN scheme, uses random resistors with values chosen from a quasi-continuum set. It is well-known since the creation of the KLJN concept that such a system could work in cryptography, because Alice and Bob can calculate the unknown resistance value from measurements, but the RR-KLJN system has not been addressed in prior publications since it was considered impractical. The reason for discussing it now is the second scheme, the Random Resistor Random Temperature (RRRT- KLJN key exchange, inspired by a recent paper of Vadai, Mingesz and Gingl, wherein security was shown to be maintained at non-zero power flow. In the RRRT-KLJN secure key exchange scheme, both the resistances and their temperatures are continuum random variables. We prove that the security of the RRRT-KLJN scheme can prevail at a non-zero power flow, and thus the physical law guaranteeing security is not the Second Law of Thermodynamics but the Fluctuation-Dissipation Theorem. Alice and Bob know their own resistances and temperatures and can calculate the resistance and temperature values at the other end of the communication channel from measured voltage, current and power-flow data in the wire. However, Eve cannot determine these values because, for her, there are four unknown quantities while she can set up only three equations. The RRRT-KLJN scheme has several advantages and makes all former attacks on the KLJN scheme invalid or incomplete.

  2. On γ-Fe→α-Fe in pure iron and pealitic in eutectoid steel transformation and ordered displacement mechanism of iron atom individuals at transitional phase boundary%纯铁γ-Fe到α-Fe和共析钢的珠光体转变与过渡相界铁原子个体有序位移机制

    Institute of Scientific and Technical Information of China (English)

    俞德刚

    2012-01-01

    The γ-Fe→α-Fe transformation of pure iron obeys the mechanism of iron atom individuals displacement of the transitional phase boundary, this mechanism is essentially equivalent to classical shear and different from diffusional mechanism. All the precipitation of proeutectoid ferrite certainly obeys the individual ordered displacement mechanism of iron atom at the transitional phase boundary, it is the first rule of solid transformation. Prior exclusion of carbon content of overcooling austenite is prerequisite for phase transformation of the overcooling non-carbon austenite to non-carbon ferrite, it is the second rule of solid transformation. The pealitic decomposition essentially is the pealitic ferrite precipitation of overcooling non-carbon austenite. It is argued that the diffusional mechanism of iron atom individual disordered displacement is not existence, and in fact the solid these transformations occurs by the mechanism of ordered displacement of multiple iron atoms or individual iron atom. The classification of shear and diffusinnal mechanism in solid transformation is meaningless.%纯铁γ-Fe的α-Fe转变遵循过渡相界铁原子个体有序位移机制,这个机制本质上等同于切变而差异于扩散机制。凡是过冷含碳奥氏体的先共析铁素体析出,必然服从相界铁原子个体有序位移机制;这是固态相变第一法则;凡是无碳铁素体必然得自过冷无碳奥氏体,故过冷含碳奥氏体务必预先除碳,这是第二法则。珠光体分解实质上为过冷无碳奥氏体的珠光体铁素体层片的析出,等轴铁素体的析出亦然。在此不存在铁原子个体无序位移扩散机制。铁碳系统固态相变存在群体有序位移切变与过渡相界个体有序机制两类型机制,切变和扩散两类型的分类不具现实和理论意义,这是固态相变物理的科学发展。

  3. A Re-examination of Kirchhoff's Law of Thermal Radiation in Relation to Recent Criticisms (Letters to Progress in Physics)

    OpenAIRE

    Johnson R. J.

    2016-01-01

    This paper investigates claims made by Pierre-Marie Robitaille in a series of papers from 2003 to 2015 that Kirchhoff’s Law of thermal radiation does not apply to cavities made of arbitrary materials, and that Planck’s theoretical derivation and apparent proof of this law in these cases is faulty. Robitaille’s claims are compared to statements in the original papers by Kirchhoff and Planck. The present paper concludes that Robitaille’s claims are not sustainable and th...

  4. Molecular-dynamics simulation of threshold displacement energies in BaTiO3

    Science.gov (United States)

    Gonzalez, E.; Abreu, Y.; Cruz, C. M.; Piñera, I.; Leyva, A.

    2015-09-01

    Molecular-dynamics simulations were used to calculate threshold displacement energies for each atom type in BaTiO3 perovskite. A primary knock-on atom with an energy range between 10 and 300 eV in principal crystallographic directions at 300 K was introduced. A statistical approach has been applied calculating displacement probability curves along main crystallographic directions. For each sublattice, the simulation was repeated from different initial conditions to estimate the uncertainty in the threshold displacement energy calculated values. The threshold displacement energies vary considerably with crystallographic direction and sublattice. The weighted average threshold displacement energies are 40 eV for oxygen, 64 eV for barium and 97 eV for titanium atoms. These values are comparable to ab initio calculated and experimentally derived values in perovskites. These results are proposed as threshold displacement energies, ideal for simulation programs that use atomic displacement calculation algorithms.

  5. Numerical analysis on noise of rotor with unconventional blade tips based on CFD/Kirchhoff method

    Institute of Scientific and Technical Information of China (English)

    Wang Bo; Zhao Qijun; Xu Guohua; Ye Liang; Wang Junyi

    2013-01-01

    A solver is developed aiming at efficiently predicting rotor noise in hover and forward flight.In this solver,the nonlinear near-field solutions are calculated by a hybrid approach which includes the Navier-Stokes and Euler equations based on a moving-embedded grid system and adaptive grid methodology.A combination of the third-order upwind scheme and flux-difference splitting scheme,instead of the second-order center-difference scheme which may cause larger wake dissipation,has been employed in the present computational fluid dynamics (CFD) method.The sound pressure data in the near field can be calculated directly by solving the Navier-Stokes equations,and the sound propagation can be predicted by the Kirchhoffmethod.A harmonic expansion approach is presented for rotor far-field noise prediction,which gives an analytical expression for the integral function in the Kirchhoff formula.As a result,the interpolation process is simplified and the efficiency and accuracy of the interpolation are improved.Then,the high-speed impulsive (HIS) noise of a helicopter rotor at different tip Mach numbers and on different observers is calculated and analyzed in hover and forward flight,which shows a highly directional characteristic of the rotor HIS noise with a maximum value in the rotor plane,and the HSI noise weakens rapidly with the increasing of the directivity angle.In order to investigate the effects of the rotor blade-tip shape on its aeroacoustic characteristics,four kinds of blade tips are designed and their noise characteristics have been simulated.At last,a new unconventional CLOR-Ⅱ blade tip has been designed,and the noise characteristics of the presented CLOR-Ⅱ model rotor have been simulated and measured compared to the reference rotors with a rectangular or swept-back platform blade tip.The results demonstrate that the unconventional CLOR-Ⅱblade tip can significantly reduce the HSI noise of a rotor.

  6. A non-classical Kirchhoff plate model incorporating microstructure, surface energy and foundation effects

    Science.gov (United States)

    Gao, X.-L.; Zhang, G. Y.

    2016-03-01

    A new non-classical Kirchhoff plate model is developed using a modified couple stress theory, a surface elasticity theory and a two-parameter elastic foundation model. A variational formulation based on Hamilton's principle is employed, which leads to the simultaneous determination of the equations of motion and the complete boundary conditions and provides a unified treatment of the microstructure, surface energy and foundation effects. The new plate model contains a material length scale parameter to account for the microstructure effect, three surface elastic constants to describe the surface energy effect, and two foundation moduli to represent the foundation effect. The current non-classical plate model reduces to its classical elasticity-based counterpart when the microstructure, surface energy and foundation effects are all suppressed. In addition, the newly developed plate model includes the models considering the microstructure dependence or the surface energy effect or the foundation influence alone as special cases and recovers the Bernoulli-Euler beam model incorporating the microstructure, surface energy and foundation effects. To illustrate the new model, the static bending and free vibration problems of a simply supported rectangular plate are analytically solved by directly applying the general formulas derived. For the static bending problem, the numerical results reveal that the deflection of the simply supported plate with or without the elastic foundation predicted by the current model is smaller than that predicted by the classical model. Also, it is observed that the difference in the deflection predicted by the new and classical plate models is very large when the plate thickness is sufficiently small, but it is diminishing with the increase of the plate thickness. For the free vibration problem, it is found that the natural frequency predicted by the new plate model with or without the elastic foundation is higher than that predicted by the

  7. The photoelectric displacement converter

    Science.gov (United States)

    Dragoner, Valeriu V.

    2005-02-01

    In the article are examined questions of constructing photoelectric displacement converter satisfying demands that are stated above. Converter has channels of approximate and precise readings. The approximate reading may be accomplished either by the method of reading from a code mask or by the method of the consecutive calculation of optical scale gaps number. Phase interpolator of mouar strips" gaps is determined as a precise measuring. It is shown mathematical model of converter that allow evaluating errors and operating speed of conversion.

  8. HIGH TEMPERATURE DISPLACEMENT SENSOR

    Institute of Scientific and Technical Information of China (English)

    Xu Longxiang; Zhang Jinyu; Schweitzer Gerhard

    2005-01-01

    A high temperature displacement sensor based on the principle of eddy-current is investigated. A new temperature compensation technique by using eddy-current effect is presented to satisfy the special requirement at high temperature up to 550℃. The experiment shows that the temperature compensation technique leads to good temperature stability for the sensors. The variation of the sensitivity as well as the temperature drift of the sensor with temperature compensation technique is only about 7.4% and 90~350 mV at 550℃ compared with that at room temperature, and that of the sensor without temperature compensation technique is about 31.2% and 2~3 V at 550℃ compared with that at room temperature. A new dynamic calibration method for the eddy-current displacement sensor is presented, which is very easy to be realized especially in high frequency and at high temperatures. The high temperature displacement sensors developed are successfully used at temperature up to 550℃ in a magnetic bearing system for more than 100 h.

  9. Nonlinear vertical displacement instability of elongated plasma in tokamak and its stabilization

    International Nuclear Information System (INIS)

    Nonlinear vertical displacement instability (nonlinear VDI) for highly elongated plasma with a finite cross-section in tokamak is investigated by solving the equation of plasma motion and Kirchhoff equations of the surrounding conductors. The results show that there are two components of VDI, namely a fast oscillation with a period of few microseconds and a slow shift with a characteristic time comparable to the resistive time of the conductors. The critical elongation for VDI can be explained as that beyond which the fast oscillation can not be suppressed by the passive inductions in the conductors. The active controlling system usually can play almost no role in the elevation of the critical elongation. As an alternative approach, the dynamic stabilization of VDI proposed is shown to be feasible. Its simplicity and wide range of working frequencies indicate that it would be a potentially promising stabilizing method. (author) 6 figs

  10. Dispossession and displacement in Libya

    OpenAIRE

    Rhodri C Williams

    2012-01-01

    Inability to access pre-displacement housing, land and property poses a significant obstacle to the achievement of durable solutions for most IDPs in Libya. Displacement and dispossession cannot be separated from the legacy of the Gaddafi era.

  11. Virtual Displacement in Lagrangian Dynamics

    CERN Document Server

    Ray, S; Ray, Subhankar

    2004-01-01

    The confusion and ambiguity encountered by students, in understanding virtual displacement and virtual work, is addressed in this article. A definition of virtual displacement is presented that allows one to express them explicitly for both time independent and time dependent constraints. It is observed that for time independent constraints the virtual displacements are the displacements allowed by the constraints. However this is not so for a general time dependent case. For simple physical systems, it is shown that, the work done on virtual displacements by the constraint forces is zero in both the situations. For allowed displacements however, this is not always true. It is also demonstrated that when constraint forces do zero work on virtual displacement, as defined here, we have a solvable mechanical problem. We identify this special class of constraints, physically realized and solvable, as the ideal constraints. The concept of virtual displacement and the principle of zero virtual work by constraint fo...

  12. Static and dynamic stability results for a class of three-dimensional configurations of Kirchhoff elastic rods

    KAUST Repository

    Majumdar, Apala

    2013-06-01

    We analyze the dynamical stability of a naturally straight, inextensible and unshearable elastic rod, under tension and controlled end rotation, within the Kirchhoff model in three dimensions. The cases of clamped boundary conditions and isoperimetric constraints are treated separately. We obtain explicit criteria for the static stability of arbitrary extrema of a general quadratic strain energy. We exploit the equivalence between the total energy and a suitably defined norm to prove that local minimizers of the strain energy, under explicit hypotheses, are stable in the dynamic sense due to Liapounov. We also extend our analysis to damped systems to show that static equilibria are dynamically stable in the Liapounov sense, in the presence of a suitably defined local drag force. © 2013 Elsevier B.V. All rights reserved.

  13. 矢量波场弹性波Kirchhoff偏移%Elastic Kirchhoff migration of vectorial wave-fields

    Institute of Scientific and Technical Information of China (English)

    杜启振; 侯波

    2008-01-01

    Based on Kuo and Dai's vectorial wave-field extrapolation equations, we derive new Kirchhoff migration equations by introducing unit vectors which represent the ray directions at the imaging points of the reflected P- and PS converted-waves. Furthermore, using the slope of the events on shot records and a ray racing procedure, mirror-image reflection points are found and the reflection data are smeared along the Fresnel zone. The migration method proposed in this paper solves two troublesome imaging problems caused by limited receiving aperture and migration artifacts resulting from wave propagation at the velocities of non original wave type. The migration method is applied successfully with model data, demonstrating that the new method is effective and correct.

  14. The Helmholtz-Kirchhoff integral relation as a framework for developing algorithms for sound propagation through inhomogeneous moving media

    Science.gov (United States)

    Pierce, Allan D.

    1989-01-01

    Transient sound propagation in an inhomogeneous moving medium is considered. For circumstances in which the medium is slowly varying over distances of a wavelength but possibly varying substantially over the propagation distance, a derivation is given of a new wave equation, which implicitly allows for diffraction and scattering and which also is consistent with earlier geometrical acoustics formulations. This wave equation is used as a starting point to derive a version of the Helmholtz-Kirchhoff integral relation that applies to inhomogeneous moving medium. It is suggested that a good approximation to the Green's function that appears in this relation is that derived from geometrical acoustics, the approximation becoming progressively better the shorter the distance between surfaces in the computation. It should also be at least as good as conventional ray acoustics, but can account for diffraction effects, such as at caustics.

  15. Helium vs. Proton Induced Displacement Damage in Electronic Materials

    Science.gov (United States)

    Ringo, Sawnese; Barghouty, A. F.

    2010-01-01

    In this project, the specific effects of displacement damage due to the passage of protons and helium nuclei on some typical electronic materials will be evaluated and contrasted. As the electronic material absorbs the energetic proton and helium momentum, degradation of performance occurs, eventually leading to overall failure. Helium nuclei traveling at the same speed as protons are expected to impart more to the material displacement damage; due to the larger mass, and thus momentum, of helium nuclei compared to protons. Damage due to displacement of atoms in their crystalline structure can change the physical properties and hence performance of the electronic materials.

  16. Strategies for displacing oil

    Science.gov (United States)

    Rao, Vikram; Gupta, Raghubir

    2015-03-01

    Oil currently holds a monopoly on transportation fuels. Until recently biofuels were seen as the means to break this stranglehold. They will still have a part to play, but the lead role has been handed to natural gas, almost solely due to the increased availability of shale gas. The spread between oil and gas prices, unprecedented in its scale and duration, will cause a secular shift away from oil as a raw material. In the transport fuel sector, natural gas will gain traction first in the displacement of diesel fuel. Substantial innovation is occurring in the methods of producing liquid fuel from shale gas at the well site, in particular in the development of small scale distributed processes. In some cases, the financing of such small-scale plants may require new business models.

  17. Displacing the patient

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2014-01-01

    target groups for which information can be standardized. In the latter approach (market orientation), the patient is also a resource for organizational development. Overall, the strategy presents an information-pursuing patient figure that makes it possible to streamline the organization's care...... in Copenhagen, Denmark. Based on situational analysis of internal documents, the paper gives an empirical account of the work of strategic documents and explores how the documents organize patient communication through displacements of the patient. This paper shows that the hospital’s patient...... communication is not only about disease treatment, but also about ‘information treatment’ for the purpose of increasing patient satisfaction at the hospital. The goal of patient satisfaction addresses both a care-oriented approach to the patient and also deploys market perceptions of patients as homogeneous...

  18. Displacing the Patient

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    as an affective care recipient, as a citizen with rights and as an individual need-oriented user on the one hand. On the other hand, the goal of patient satisfaction also deploys market perceptions of patients as homogeneous target groups to which information can be standardised. In the latter......The analysis is based on an empirical study of a hospital’s communication strategy entitled: 'The Perspective of the Patient'. The paper asks how the strategy organizes communication work as situated displacements of the patient. Based on methodological elements from situational analysis (Clarke...... 2005) the analysis examines how the hospital’s patient communication is not just about disease treatment, but rather about information treatment of the patient in order to attain a high level of patient satisfaction. The goal of patient satisfaction addresses care-oriented understandings of the patient...

  19. Displacing the patient

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2012-01-01

    a care-oriented approach to the patient and also deploys market perceptions of patients as homogeneous target groups to which information can be standardized. In the latter approach (market orientation), the patient is also a resource for organizational development. Overall, the strategy presents an......This analysis is based on an empirical study of a Danish hospital‟s communication programme entitled: 'The Perspective of the Patient'. The paper explores how strategic documents of the programme organize the communication work through situated displacements of the patient. Based on methodological...... elements from situational analysis (Clarke 2005) the analysis examines how the hospital‟s patient communication is not only about disease treatment, but rather about information treatment of the patient in order to attain a high level of patient satisfaction. The goal of patient satisfaction addresses both...

  20. Displacement Parameter Inversion for a Novel Electromagnetic Underground Displacement Sensor

    OpenAIRE

    Nanying Shentu; Qing Li; Xiong Li; Renyuan Tong; Nankai Shentu; Guoqing Jiang; Guohua Qiu

    2014-01-01

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic el...

  1. Displacement Parameter Inversion for a Novel Electromagnetic Underground Displacement Sensor

    Directory of Open Access Journals (Sweden)

    Nanying Shentu

    2014-05-01

    Full Text Available Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA. Based on that work, this paper presents an underground displacement inversion approach named “EELA forward modeling-approximate inversion method”. Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0–100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications.

  2. Displacement parameter inversion for a novel electromagnetic underground displacement sensor.

    Science.gov (United States)

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-01-01

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named "EELA forward modeling-approximate inversion method". Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0-100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications. PMID:24858960

  3. A Rigorous Derivation of the Equations for the Clamped Biot-Kirchhoff-Love Poroelastic plate

    CERN Document Server

    Marciniak-Czochra, Anna

    2012-01-01

    In this paper we investigate the limit behavior of the solution to quasi-static Biot's equations in thin poroelastic plates as the thickness tends to zero. We choose Terzaghi's time corresponding to the plate thickness and obtain the strong convergence of the three-dimensional solid displacement, fluid pressure and total poroelastic stress to the solution of the new class of plate equations. In the new equations the in-plane stretching is described by the 2D Navier's linear elasticity equations, with elastic moduli depending on Gassmann's and Biot's coefficients. The bending equation is coupled with the pressure equation and it contains the bending moment due to the variation in pore pressure across the plate thickness. The pressure equation is parabolic only in the vertical direction. As additional terms it contains the time derivative of the in-plane Laplacean of the vertical deflection of the plate and of the the elastic in-plane compression term.

  4. Exact solution for inner displacements of graphene lattice

    Energy Technology Data Exchange (ETDEWEB)

    Zubko, I. Yu., E-mail: zoubko@list.ru [Perm National Research Polytechnic University, Perm, 614990 (Russian Federation)

    2015-10-27

    It is shown that in the frame of lattice statics approach to finding elastic moduli the homogeneous deformation of graphene monolayer transfers it into the non-equilibrium state. It is necessary to shift part of graphene atoms which form one of its “triangular” sublattices with respect to atoms of another sublattice in order to provide the sample minimum potential energy in a deformed state, while each sublattice is deformed homogeneously. Taking into account these inner displacements of graphene lattice allows obtaining more precise estimations of its elastic moduli. The exact expression for the vector of inner displacements depending on applied deformations and specimen size is found.

  5. Measuring vulnerability to disaster displacement

    Science.gov (United States)

    Brink, Susan A.; Khazai, Bijan; Power, Christopher; Wenzel, Friedemann

    2015-04-01

    Large scale disasters can cause devastating impacts in terms of population displacement. Between 2008 and 2013, on average 27 million people were displaced annually by disasters (Yonetani 2014). After large events such as hurricane Katrina or the Port-au-Prince earthquake, images of inadequate public shelter and concerns about large scale and often inequitable migration have been broadcast around the world. Population displacement can often be one of the most devastating and visible impacts of a natural disaster. Despite the importance of population displacement in disaster events, measures to understand the socio-economic vulnerability of a community often use broad metrics to estimate the total socio-economic risk of an event rather than focusing on the specific impacts that a community faces in a disaster. Population displacement is complex and multi-causal with the physical impact of a disaster interacting with vulnerability arising from the response, environmental issues (e.g., weather), cultural concerns (e.g., expectations of adequate shelter), and many individual factors (e.g., mobility, risk perception). In addition to the complexity of the causes, population displacement is difficult to measure because of the wide variety of different terms and definitions and its multi-dimensional nature. When we speak of severe population displacement, we may refer to a large number of displaced people, an extended length of displacement or associated difficulties such as poor shelter quality, risk of violence and crime in shelter communities, discrimination in aid, a lack of access to employment or other difficulties that can be associated with large scale population displacement. We have completed a thorough review of the literature on disaster population displacement. Research has been conducted on historic events to understand the types of negative impacts associated with population displacement and also the vulnerability of different groups to these impacts. We

  6. 基于MPI和CUDA的转换波Kirchhoff 叠前时间偏移并行计算%Converted-wave Kirchhoff prestack time migration parallel computation based on MPI+CUDA

    Institute of Scientific and Technical Information of China (English)

    喻勤; 张少华; 孔选林

    2013-01-01

    Converted-wave Kirchhoff prestack time migration can image accurately in 3-D space. However, the prestack time migration generates huge computation amount and need migration for several times to discover matched migration velocity model, which leads to long processing period and low efficiency,and restricts the application scale in productioa Nowadays,CPU-cluster computation is applied widely to solve the problem, but the CPU-cluster has some disadvantages such as high cost, large power consumption, large space occupation and high maintenance cost. In order to improve the time-consuming and save the computing cost, we proposed a parallel algorithm of converted-wave Kirchhoff prestack time migration based on MPI+CUDA, which merged the GPU parallel computation of fine-grained thread-level into the MPI parallel programming model of coarse-grained process-level. We tested the performance of the parallel algorithm on CPU (single core),GPU (single card), MPI+GPU (2 nodes). The testing results indicate that the computation speed of the MPI + GPU (2 nodes) platform is nearly 400 times of the CPU's (single core),largely improves the computation efficiency of converted-wave Kirchhoff prestack time migration and decreases the computation cost.%转换波Kirchhoff叠前时间偏移可以实现全空间三维转换波资料的准确成像.但转换波叠前偏移数据量巨大,而且需偏移迭代多次来寻找匹配的偏移速度模型,导致偏移处理周期长、效率低,限制了转换波偏移技术在生产上的应用规模.目前解决海量运算问题的方法主要是应用CPU集群来提高计算效率,但集群存在成本高、功耗大、占用空间大、维护成本高等缺点.给出了一种基于MPI(Message Passing Interface)和CUDA的转换波Kirchhoff叠前时间偏移并行算法,将细粒度线程级的GPU(Graphic Processing Unit)并行计算融入粗粒度进程级MPI并行编程模型.利用实际转换波数据分别在CPU

  7. Point Coupled Displacement Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Real-time displacement measurement techniques are needed to acquire aerodynamic and structural system characteristics in flight. This proposal describes the...

  8. Analysis of an Attenuator Artifact in an Experimental Attack by Gunn-Allison-Abbott Against the Kirchhoff-Law-Johnson-Noise (KLJN) Secure Key Exchange System

    Science.gov (United States)

    Kish, Laszlo B.; Gingl, Zoltan; Mingesz, Robert; Vadai, Gergely; Smulko, Janusz; Granqvist, Claes-Göran

    2015-12-01

    A recent paper by Gunn-Allison-Abbott (GAA) [L. J. Gunn et al., Scientific Reports 4 (2014) 6461] argued that the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system could experience a severe information leak. Here we refute their results and demonstrate that GAA's arguments ensue from a serious design flaw in their system. Specifically, an attenuator broke the single Kirchhoff-loop into two coupled loops, which is an incorrect operation since the single loop is essential for the security in the KLJN system, and hence GAA's asserted information leak is trivial. Another consequence is that a fully defended KLJN system would not be able to function due to its built-in current-comparison defense against active (invasive) attacks. In this paper we crack GAA's scheme via an elementary current-comparison attack which yields negligible error probability for Eve even without averaging over the correlation time of the noise.

  9. Protection against the man-in-the-middle-attack for the Kirchhoff-loop-Johnson(-like)-noise cipher and expansion by voltage-based security

    OpenAIRE

    Kish, Laszlo B.

    2005-01-01

    It is shown that the original Kirchhoff-loop-Johnson(-like)-noise (KLJN) cipher is naturally protected against the man-in-the-middle (MITM) attack, if the eavesdropper is using resistors and noise voltage generators just like the sender and the receiver. The eavesdropper can extract zero bit of information before she is discovered. However, when the eavesdropper is using noise current generators, though the cipher is protected, the eavesdropper may still be able to extract one bit of informat...

  10. Displacement, Substitution, Sublimation: A Bibliography.

    Science.gov (United States)

    Pedrini, D. T.; Pedrini, Bonnie C.

    Sigmund Freund worked with the mechanisms of displacement, substitution, and sublimation. These mechanisms have many similarities and have been studied diagnostically and therapeutically. Displacement and substitution seem to fit in well with phobias, hysterias, somatiyations, prejudices, and scapegoating. Phobias, prejudices, and scapegoating…

  11. The management of climate displacement

    Directory of Open Access Journals (Sweden)

    Scott Leckie

    2012-12-01

    Full Text Available Many of those who have fought against displacement now find themselves being advocates for resettlement and relocation. Knowing that displacements will occur as a result of climate change,the humanitarian community will need to work pre-emptively with communities identified as likely to be threatened on the land-based solutions that may be available to them.

  12. 基于场论谈基尔霍夫定律新的表达式推导%New Expression of Kirchhoff's Law Based on Field Theory

    Institute of Scientific and Technical Information of China (English)

    殷忠玲; 刘秉安; 冯关平

    2011-01-01

    Kirchhoff s law is a basic law of circuit, while the Maxwell equations is a basic law of electromagnetic field. To study the theoretical basis for transmission line, a new expression of Kirchhoff's current law and voltage law is derived and studied by field theory (electrical network theory). The new expression discusses the relations between Kirchhoff's law and field theory (electrical network theory), provides a reference for the transmission, reflection and application of signal in the PCB, and further analyzes the transmission line theory.%基尔霍夫定律是电路基本定律,而麦克斯韦方程组则是电磁场基本定律.为了研究传输线所要用到的理论基础,采用场论思想(又称电网络理论),通过推导和研究得到了基尔霍夫电流定律和电压定律的新表示式,该新表示式对探讨基尔霍夫定律与场论(电网络理论)之间的关系,进一步研究传输线理论、信号在PCB的传播、反射及应用有一定的借鉴作用.

  13. A displacement-doubling prism

    International Nuclear Information System (INIS)

    A novel prism has been devised which can be used in place of the ‘flag’ in an optical shadow-sensing type of displacement sensor, for example. In this way, theoretically the displacement sensitivity of the sensor can be doubled. Such a prism has been manufactured, and its displacement-doubling property has been verified. - Highlights: • A new type of glass prism doubles linear displacement of optical beams. • Optical operation has been verified. • Light beams enter and exit at normal incidence to prism's windows. • Optical path length through prism remains constant, as prism is moved. • Designed to double the displacement sensitivity of knife-edge shadow sensors

  14. Three-dimensional pre-stack depth migration of receiver functions with the fast marching method: a Kirchhoff approach

    Science.gov (United States)

    Cheng, Cheng; Bodin, Thomas; Allen, Richard M.

    2016-05-01

    We present a novel 3-D pre-stack Kirchhoff depth migration (PKDM) method for teleseismic receiver functions. The proposed algorithm considers the effects of diffraction, scattering and traveltime alteration caused by 3-D volumetric heterogeneities. It is therefore particularly useful for imaging complex 3-D structures such as dipping discontinuities, which is hard to accomplish with traditional methods. The scheme is based on the acoustic wave migration principle, where at each time step of the receiver function, the energy is migrated back to the ensemble of potential conversion points in the image, given a smooth 3-D reference model. Traveltimes for P and S waves are computed with an efficient eikonal solver, the fast marching method. We also consider elastic scattering patterns, where the amplitude of converted S waves depends on the angle between the incident P wave and the scattered S wave. Synthetic experiments demonstrate the validity of the method for a variety of dipping angle discontinuities. Comparison with the widely used common conversion point (CCP) stacking method reveals that our migration shows considerable improvement. For example, the effect of multiple reflections that usually produce apparent discontinuities is avoided. The proposed approach is practical, computationally efficient, and is therefore a potentially powerful alternative to standard CCP methods for imaging large-scale continental structure under dense networks.

  15. Is Fibular Fracture Displacement Consistent with Tibiotalar Displacement?

    OpenAIRE

    van den Bekerom, Michel P. J.; van Dijk, C. Niek

    2009-01-01

    We believed open reduction with internal fixation is required for supination-external rotation ankle fractures located at the level of the distal tibiofibular syndesmosis (Lauge-Hanssen SER II and Weber B) with 2 mm or more fibular fracture displacement. The rationale for surgery for these ankle fractures is based on the notion of elevated intraarticular contact pressures with lateral displacement. To diagnose these injuries, we presumed that in patients with a fibular fracture with at least ...

  16. Nano-scale displacement sensing based on Van der Waals interaction

    OpenAIRE

    Hu, Lin; Zhao, Jin; Yang, Jinlong

    2014-01-01

    We propose the nano-scale displacement sensor with high resolution for weak-force systems could be realized based on vertical stacked two-dimensional (2D) atomic corrugated layer materials bound through Van der Waals (VdW) interaction. Using first-principles calculations, we found the electronic structure of bi-layer blue phosphorus (BLBP) varies appreciably to both the lateral and vertical interlayer displacement. The variation of electronic structure due to the lateral displacement is attri...

  17. Internal displacement in eastern Burma

    Directory of Open Access Journals (Sweden)

    Heather Rae

    2007-07-01

    Full Text Available The history of post-independent Burma is characterisedby numerous conflicts in this extraordinarily heterogeneous country. Since military rule began in 196 2 Burmahas witnessed gross human rights abuses andmassive displacement.

  18. A novel linear displacement sensor

    Science.gov (United States)

    Yang, Ji-sen; Zhang, Jing; Chen, Xi-hou; Zhang, Tian-heng

    2011-12-01

    With development of time grating technology in the past 10 years, the theory of using time to measure spatial displacement has been completed greatly. In the study of time grating, one novel linear displacement sensor is proposed based on the measurement principles of time grating. The measurement principles of linear displacement are similar to that of angular displacement. Both of them need one endless coordinate with uniform velocity. The theory of linear AC motor is used, and the three-phase winding with equal division space of 120° and three-phase exciting signal with uniform time are utilized to generate the endless moving coordinate with uniform velocity. The magnetic traveling wave arises from the left endpoint and disappears in the right endpoint, and it travels pole pitch distance of W during the periodic time of T with the uniform velocity. When magnetic traveling wave passes by the static probe and the moving probe, the electric signals will be induced on the winding, respectively. Therefore, the linear displacement can be achieved by comparing the phase between the two output induced signals from he static probe and the moving probe. Furthermore, in order to improve the machining technique, four kinds of winding framework are designed to employ. The experimental results show that advantages and disadvantages both exist in the design methods and the precision of experiment results reaches +/-2µm. The next study plan is to choose the most excellent design method through further experiments and improve the precision of displacement sensor greatly.

  19. Validity of Kirchhoff Theory for Electromagnetic Wave Scattering from Random Rough Surfaces with Emphasis on Fractal Models

    Science.gov (United States)

    Sultan Salem, A. K.; Tyler, G. L.

    2002-09-01

    Understanding of electromagnetic scattering from surfaces is essential to interpretation of planetary radar observation of solid bodies, radio wave surface sounding from orbit, and many planetary remote sensing problems. The validity of Kirchhoff theory (KT) for analysis of scattering from fractal surfaces has not been clearly established. KT is exact for surfaces that are infinite, planar, and smooth. For other types of surfaces, KT is an approximation that has limited validity. The first limitation pertains to the local radius of curvature of the rough surface. The second pertains to the surface correlation length. By comparing the results from KT with empirical results, many authors assert the prime importance of the ratio of the correlation length to the wavelength (e.g., J.A. Ogilvy, Theory of Wave Scattering from Random Rough Surfaces, 104-110, Adam Hilger 1991). The larger this ratio, the better KT agrees with experimental results. We reformulate the second limitation as follows: The maximum wavelength should not exceed the correlation length of the surface for a valid application of KT. Since fractal functions are nowhere differentiable, band-limited fractals are used as models for physical surfaces. As first steps, some ad hoc procedures are used to band-limit the fractal surfaces before calculating the correlation length and local radius of curvature. Afterwards, a check is made to make sure that scattering can be analyzed accurately using KT. This check is extended to previous works that employ KT with fractal models (G. Franceschetti et al. 1999, M.K. Shepard and B.A. Campell 1999). The obtained results refer to the rigorous determination of a hypothesized filtering function (previously alluded to by Hagfors) to band-limit the mathematical fractal, transforming it into a physical representation for scattering calculations. The filtering function, if found, is expected to be helpful in understanding scattering from many types of surface models.

  20. Kirchhoff Index of Linear Tetragonal Chains and Tetragonal Moöbius Graphs%线性四角链及四角莫比乌斯图的Kirchhoff指标

    Institute of Scientific and Technical Information of China (English)

    王广富; 鲁玖环

    2016-01-01

    图G的Kirchhoff指标是指图G的所有点对之间的电阻距离之和。主要研究了线性四角链及四角莫比乌斯图的Kirchhoff指标。根据拉普拉斯多项式分解定理、Kirchhoff指标和拉普拉斯特征值之间的关系以及矩阵分解定理等得到线性四角链及四角莫比乌斯图的Kirchhoff指标计算公式;最后,通过举例直接利用欧姆定律所得Kirchhoff指标对所求公式加以验证。%The Kirchhoff index of G is the sum of resistance distances between all pairs of vertices in G. This pa-per studies the Kirchhoff index of linear tetragonal chains and tetragonal Moöbius graphs. According to the Lapla-cian polynomial decomposition theorem, the relationship between Kirchhoff index and the Laplacian eigenvalues, matrix decomposition theorem, this paper obtains formula for Kirchhoff index of linear tetragonal chains and te-tragonal Mo咬bius graphs. Finally, it verifies the formula using two examples whose Kirchhoff indexes are obtained from Ohm's law.

  1. Formation around planetary displaced orbit

    Institute of Scientific and Technical Information of China (English)

    GONG Sheng-ping; LI Jun-feng; BAOYIN He-xi

    2007-01-01

    The paper investigates the relative motion around the planetary displaced orbit. Several kinds of displaced orbits for geocentric and martian cases were discussed. First, the relative motion was linearized around the displaced orbits. Then, two seminatural control laws were investigated for each kind of orbit and the stable regions were obtained for each case. One of the two control laws is the passive control law that is very attractive for engineering practice. However, the two control laws are not very suitable for the Martian mission. Another special semi-natural control law is designed based on the requirement of the Martian mission. The results show that large stable regions exist for the control law.

  2. De la mecánica clásica y las leyes de Kirchhoff a los sistemas hamiltonianos con puertos

    OpenAIRE

    Batlle Arnau, Carles; Dòria Cerezo, Arnau

    2010-01-01

    En este artículo exponemos los orígenes conceptuales de la teoría PHS (port-Hamiltonian systems), empezando por las leyes de Kirchhoff y enlazando con las ecuaciones de la mecánica clásica, para acabar con la estructura geométrica subyacente a todo el formalismo, conocida como estructura de Dirac, y con los métodos de control asociados. Concluimos con un apunte de las generalizaciones y desarrollos más recientes.

  3. Perceived Displacement explains Wolfpack Effect

    Directory of Open Access Journals (Sweden)

    Matúš eŠimkovic

    2014-12-01

    Full Text Available We investigate the influence of perceived displacement of moving agent-like stimuli on the performance in dynamic interactive tasks. In order to reliably measure perceived displacement we utilize multiple tasks with different task demands. The perceived center of an agent’s body is displaced in the direction in which the agent is facing and this perceived displacement is larger than the theoretical position of the center of mass would predict. Furthermore, the displacement in the explicit judgment is dissociated from the displacement obtained by the implicit measures. By manipulating the location of the pivot point, we show that it is not necessary to postulate orientation as an additional cue utilized by perception, as has been suggested by earlier studies. These studies showed that the agent’s orientation influences the detection of chasing motion and the detection-related performance in interactive tasks. This influence has been labeled wolfpack effect. In one of the demonstrations of the wolfpack effect participants control a green circle on a display with a computer mouse. It has been shown that participants avoid display areas withagents pointing towards the green circle. Participants do so in favor of areas where the agents point in the direction perpendicular to the circle. We show that this avoidance behavior arises because the agent’s pivot point selected by the earlier studies is different from where people locate the center of agent’s body. As a consequence, the nominal rotation confounds rotation and translation. We show that the avoidance behavior disappears once the pivot point is set to the center of agent’s body.

  4. Displacement disorder and reconstruction of the (001) face of tungsten

    International Nuclear Information System (INIS)

    The reconstruction of the (001) border of tungsten is examined taking into consideration random static displacements of surface atoms in the high-temperature (1 x 1) phase. A microscopic model is proposed, in which the creation of c(2 x 2) phase is described as a transition of the Jahn-Teller type and an ordering of static displacements. It is shown that displacement disorder induces instability of (001) tungsten with respect to reconstruction. The effect of a uniform electric field on a disordered reconstructing surface is examined. A possible reason is given for pronounced differences in the results of investigations of the structural conversion of the (001) face in tungsten when different experimental methods are used

  5. Displacement cross sections of electron irradiated graphene and carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Qiang [College of Nuclear Science and Technology, Harbin Engineering University, Harbin 150001 (China); Wang, Jing [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77843 (United States); Department of Materials Science and Engineering, Texas A& M University, College Station, TX 77843 (United States); Chen, Di; Gigax, Jonathan [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77843 (United States); Shao, Lin, E-mail: lshao@tamu.edu [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77843 (United States); Department of Materials Science and Engineering, Texas A& M University, College Station, TX 77843 (United States)

    2015-05-01

    We calculate the displacement cross-sections (DCS) of low dimensional carbon systems under electron irradiation and present an analytical formula being able to evaluate displacement creations under various conditions. The calculations consider Mott scattering, charge screening effects and thermal vibrations of target atoms. DCS values of graphene and single-walled carbon nanotubes (SWNTs) as a function of electron beam energies, substrate temperatures, and tube diameters are calculated through combination with carbon threshold displacement energies obtained from molecular dynamics simulations. For SWNTs, the smaller the tube diameters the higher the DCS values. Such diameter dependence is the most pronounced for low energy electron beams. Furthermore, DCS values are most sensitive to temperatures when electron beam energy is low. However, the temperature sensitivity disappears at higher electron energy, specifically at 200 keV and beyond.

  6. DISPLACEMENT BASED SEISMIC DESIGN METHODS.

    Energy Technology Data Exchange (ETDEWEB)

    HOFMAYER,C.MILLER,C.WANG,Y.COSTELLO,J.

    2003-07-15

    A research effort was undertaken to determine the need for any changes to USNRC's seismic regulatory practice to reflect the move, in the earthquake engineering community, toward using expected displacement rather than force (or stress) as the basis for assessing design adequacy. The research explored the extent to which displacement based seismic design methods, such as given in FEMA 273, could be useful for reviewing nuclear power stations. Two structures common to nuclear power plants were chosen to compare the results of the analysis models used. The first structure is a four-story frame structure with shear walls providing the primary lateral load system, referred herein as the shear wall model. The second structure is the turbine building of the Diablo Canyon nuclear power plant. The models were analyzed using both displacement based (pushover) analysis and nonlinear dynamic analysis. In addition, for the shear wall model an elastic analysis with ductility factors applied was also performed. The objectives of the work were to compare the results between the analyses, and to develop insights regarding the work that would be needed before the displacement based analysis methodology could be considered applicable to facilities licensed by the NRC. A summary of the research results, which were published in NUREGICR-6719 in July 2001, is presented in this paper.

  7. Experimental measurement of local displacement and chemical pair correlations in crystalline solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, C.L.; Ice, G.E.; Robertson, J.L. [Oak Ridge National Lab., TN (United States); Shaffer, L.B. [Anderson Univ., Anderson, IN (United States)

    1993-10-01

    Measurement of near-neighbor atomic arrangements in crystalline solid solutions is well established and provides meaningful values for chemical preference of atoms for their near neighbors to beyond the first ten neighboring shells. Static displacements (atomic size) between these atom pairs have mostly been either ignored in the recovery of the local pair preferences or removed by making use of the displacement scattering dependence on momentum transfer. With intense and energy tunable x-ray synchrotron sources, our ability to recover these static displacements between atoms has greatly improved. Data taken with multiple x-ray energies to obtain the contrast necessary to separate like from unlike neighbor pair distances are discussed for the two cases studied to date: A locally ordered Ni{sub 77.5}Fe{sub 22.5} crystal and a locally clustered Fe{sub 53}Cr{sub 47} crystal. Analysis of experimental parameters and data gives the systematic and statistical errors on the recovered parameters. Meaningful atomic displacements from the mean lattice can be measured and recovered. These displacements help us understand material properties and will provide theorists with tests for their calculations.

  8. PHASE CONVERTER OF COMPOSING DISPLACEMENT

    OpenAIRE

    SMIRNOV YU.S.; Lysov, A. N.; E.V. Yurasova; SAFRONOV V.V.; VSTAVSKAYA E.V.

    2016-01-01

    Minimax strategy of mechatronic converters efficiency improving relative to error decrease with velocity increase at the same time provides common dataware level rise. The analysis of usage possibilities of different type position transducers (PT) gives the advantages of resolvers. The subsequent processing of their output signals is performed by “Resolver-to-Digit” Converter (RDC) which provides displacement digital equivalent and digital or analog signals specifying its velocity and acceler...

  9. Influence of subcascade formation on displacement damage at high PKA energies

    Energy Technology Data Exchange (ETDEWEB)

    Stoller, R.E. [Oak Ridge National Lab., TN (United States); Greenwood, L.R. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-08-01

    The design of first generation fusion reactors will have to be rely on radiation effects data obtained from experiments conducted in fission reactors. Two issues must be addressed to use this data with confidence. The first is differences in the neutron energy spectrum, and the second is differences in nuclear transmutation rates. Differences in the neutron energy spectra are reflected in the energy spectra of the primary knockon atoms (PKA). The issue of PKA energy effects has been addressed through the use of displacement cascade simulations using the method of molecular dynamics (MD). Although MD simulations can provide a detailed picture of the formation and evolution of displacement cascades, they impose a substantial computational burden. However, recent advances in computing equipment permit the simulation of high energy displacement events involving more than one-million atoms; the results presented here encompass MD cascade simulation energies from near the displacement threshold to as high as 40 keV. Two parameters have been extracted from the MD simulations: the number of point defects that remain after the displacement event is completed and the fraction of the surviving interstitials that are contained in clusters. The MD values have been normalized to the number of atomic displacements calculated with the secondary displacement model by Norgett, Robinson, and Torrens (NRT).

  10. Real-time prediction of seismic ground motion (I) : real-time estimation of seismic wavefield using data assimilation technique and time evolutional prediction using Kirchhoff integral

    Science.gov (United States)

    Hoshiba, M.

    2013-05-01

    In this presentation, I propose a new approach for real-time prediction of seismic ground motion which is applicable to Earthquake Early Waning (EEW), in which hypocentral location and magnitude are not required. . Many methods of EEW are based on a network method in which hypocenter and magnitude (source parameters) are quickly determined, and then the ground motions are predicted, and warnings are issued depending on the strength of the predicted ground motion. In this method, it is necessary to determine the hypocenter and magnitude at first, and error of the source parameters leads directly to the error of the prediction. It is not easy to take the effects of rupture directivity and source extent into account, and it is impossible to fully reproduce the current wavefield from the interpreted source parameters. Time evolutional prediction is a method in which future wavefield is iteratively predicted from the wavefield at the certain time, that is u(x, t+Δt)=P(u(x, t)), where u is the wave motion at location x at lapse time t, and P is the prediction operator. Future wave motion, u(x, t+Δt), is predicted from the distribution of the current wave motion u(x, t) using P. For P, finite difference technique or boundary integral equation method, such as Kirchhoff integral, is used. Kirchhoff integral is qualitatively approximated by Huygens principle. The real time monitoring of wavefield are important for this method, but it is possible to predict ground motion without a hypocentral location and magnitude. In the time evolutional prediction, determination of detailed distribution of current wavefield is an important key, so that dense seismic observation network is required. Data assimilation is a technique to produce artificially denser network, which is widely used for numerical weather forecast and oceanography. Distribution of current wave motion is estimated from not only the current real observation of u(xi, t) where xi is the location of the i-th site, but

  11. Technology and Structural Unemployment: Reemploying Displaced Adults.

    Science.gov (United States)

    Congress of the U.S., Washington, DC. Office of Technology Assessment.

    This report concentrates on problems of displaced blue-collar and nonprofessional white-collar workers. Chapter 1 is a summary. Chapter 2 discusses policy issues and options focused on helping people prepare for worklife changes and helping workers to cope if displacement occurs. A definition and description of worker displacement are offered in…

  12. 25 CFR 700.59 - Displaced person.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Displaced person. 700.59 Section 700.59 Indians THE... Policies and Instructions Definitions § 700.59 Displaced person. Displaced person means a member of the... residing within the area partitioned to the Hopi Tribe who must be relocated pursuant to the Act. This...

  13. Proof nets for the Displacement calculus

    OpenAIRE

    Moot, Richard

    2016-01-01

    We present a proof net calculus for the Displacement calculus and show its correctness. This is the first proof net calculus which models the Displacement calculus directly and not by some sort of translation into another formalism. The proof net calculus opens up new possibilities for parsing and proof search with the Displacement calculus.

  14. Electromagnetic device of linear displacement

    International Nuclear Information System (INIS)

    The device moves a rod integral with a nuclear reactor control element. It has a grab for the rod operated by a mobil pole drive by a coil carried by a surrounding sealed casing, a second grab with fixed and mobile poles with facing surfaces shaped to limit the variation of magnetic force with distance between them, and a plunger driven by a coil to bear against another mobile pole moved by a coil. The invention proposes a device ensuring a displacement while the impact forces at the different level of the mechanism are reduced

  15. Displaced Children: The Psychological Implications.

    Science.gov (United States)

    Joshi, Paramjit T; Fayyad, John A

    2015-10-01

    Millions of people across the world have been displaced or live in exile and/or as refugees largely as a consequence of wars, acts of terrorism, and catastrophic natural disasters. There are serious psychological consequences as a result of these extremely difficult life circumstances. Adults often can express their needs and have them be heard, whereas children are unable to do so. The children may be provided food, shelter, and clothing and have their medical needs attended to, but their emotional and psychological needs go unrecognized and unmet, with dire and monumental long-term consequences. PMID:26346385

  16. Ultrasensitive detection of force and displacement using trapped ions

    Science.gov (United States)

    Biercuk, Michael J.; Uys, Hermann; Britton, Joe W.; Vandevender, Aaron P.; Bollinger, John J.

    2010-09-01

    The ability to detect extremely small forces and nanoscale displacements is vital for disciplines such as precision spin-resonance imaging, microscopy, and tests of fundamental physical phenomena. Current force-detection sensitivity limits have surpassed 1 aN Hz-1/2 (refs 6,7) through coupling of nanomechanical resonators to a variety of physical readout systems. Here, we demonstrate that crystals of trapped atomic ions behave as nanoscale mechanical oscillators and may form the core of exquisitely sensitive force and displacement detectors. We report the detection of forces with a sensitivity of 390 +/- 150 yN Hz-1/2, which is more than three orders of magnitude better than existing reports using nanofabricated devices7, and discriminate ion displacements of ~18 nm. Our technique is based on the excitation of tunable normal motional modes in an ion trap and detection through phase-coherent Doppler velocimetry, and should ultimately allow force detection with a sensitivity better than 1 yN Hz-1/2 (ref. 16). Trapped-ion-based sensors could enable scientists to explore new regimes in materials science where augmented force, field and displacement sensitivity may be traded against reduced spatial resolution.

  17. Displacement of squeezed propagating microwave states

    Science.gov (United States)

    Fedorov, Kirill G.; Zhong, Ling; Pogorzalek, Stefan; Eder, Peter; Fischer, Michael; Goetz, Jan; Wulschner, Friedrich; Xie, Edwar; Menzel, Edwin; Deppe, Frank; Marx, Achim; Gross, Rudolf

    Displacement of propagating squeezed states is a fundamental operation for quantum communications. It can be applied to fundamental studies of macroscopic quantum coherence and has an important role in quantum teleportation protocols with propagating microwaves. We generate propagating squeezed states using a Josephson parametric amplifier and implement displacement using a cryogenic directional coupler. We study single- and two-mode displacement regimes. For the single-mode displacement we find that the squeezing level of the displaced squeezed state does not depend on the displacement amplitude. Also, we observe that quantum entanglement between two spatially separated channels stays constant across 4 orders of displacement power. We acknowledge support by the German Research Foundation through SFB 631 and FE 1564/1-1, the EU project PROMISCE, and Elite Network of Bavaria through the program ExQM.

  18. A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

    Directory of Open Access Journals (Sweden)

    Xiong Li

    2011-12-01

    Full Text Available Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency.

  19. Mechanism of single atom switch on silicon

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Stokbro, Kurt; Thirstrup, C.;

    1998-01-01

    We demonstrate single atom switch on silicon which operates by displacement of a hydrogen atom on the silicon (100) surface at room temperature. We find two principal effects by which the switch is controlled: a pronounced maximum of the switching probability as function of sample bias and a...

  20. Shore line displacement in Oeregrundsgrepen

    International Nuclear Information System (INIS)

    This report is a part of the SKB project 'SAFE' (Safety Assessment of the Final Repository of Radioactive Operational Waste). The aim of project SAFE is to update the previous safety analysis of SFR-1. The analysis is to be presented to the Swedish authorities not later than the end of 2000. SFR-1 is a facility for disposal of low and intermediate level radioactive waste and is situated in bedrock beneath the Baltic Sea, 1 km off the coast near the Forsmark nuclear power plant in Northern Uppland. The shore displacement in the Oeregrundsgrepen area is at present approximately 60 cm per 100 years and is slowly decreasing, but will still be substantial for many thousands of years. Since Oeregrundsgrepen is a relatively shallow part of the Bothnian Sea, the positive shore displacement will greatly effect the proportions of land and sea in the future. Within 2000 years (4000 AD) half of the current water area in Oeregrundsgrepen will be land and the water volume will be decreased with two thirds. At 7000 AD, the whole Oeregrundsgrepen area will be without brackish water. The effects on the landscape evolution due to shore displacement in the Oeregrundsgrepen area are illustrated in a chronological series of digital maps in Power Point format available saved on the supplied CD-rom and entitled 'Elevation.ppt '. The bedrock tectonics in the area are in two dominating directions: one northern that can be seen in the west shoreline of the island Graesoe and one in a north-westerly direction seen in the shoreline of the mainland. Many of the large basins that will be established in the area due to the shore displacement will be elongated in one of these directions. Some of the basins are relatively shallow and therefore probably will be totally filled with organic rich sediments and will form peat or bogs. Other basins, especially Graesoeraennan (the deep channel on the west side of Graesoe) are deep basins and will form a long chain of deep lakes. One of the deeper basins

  1. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    Science.gov (United States)

    Connell, John W. (Inventor); Hergerrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1997-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  2. Searching for Displaced Higgs Decays

    CERN Document Server

    Csaki, Csaba; Lombardo, Salvator; Slone, Oren

    2015-01-01

    We study a simplified model of the SM Higgs boson decaying to a degenerate pair of scalars which travel a macroscopic distance before decaying to SM particles. This is the leading signal for many well-motivated solutions to the hierarchy problem that do not propose additional light colored particles. Bounds for displaced Higgs decays below $10$ cm are found by recasting existing tracker searches from Run I. New tracker search strategies, sensitive to the characteristics of these models and similar decays, are proposed with sensitivities projected for Run II at $\\sqrt{s} = 13 $ TeV. With 20 fb$^{-1}$ of data, we find that Higgs branching ratios down to $7 \\times 10^{-4}$ can be probed for centimeter decay lengths.

  3. Polyimidazoles via aromatic nucleophilic displacement

    Science.gov (United States)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1992-01-01

    Polyimidazoles (PI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl) imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethyl acetamide, sulfolane, N-methylpyrrolidinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl) imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl) imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxphenyl) imidazole monomer. This synthetic route has provided high molecular weight PI of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  4. Possible displacement of mercury's dipole

    International Nuclear Information System (INIS)

    Earlier attempts to model the Hermean magnetospheric field based on a planet-centered magnetic multipole field have required the addition of a quadrupole moment to obtain a good fit to space vehicle observations. In this work we obtain an equally satisfactory fit by assuming a null quadrupole moment and least squares fitting of the displacement of the planetary dipole from the center of the planet. We find a best fit for a dipole displacement from the planet center of 0.033 R/sub m/ away from the solar direction, 0.025 R/sub m/ toward dawn in the magnetic equatorial plane, and 0.189 R/sub m/ northward along the magnetic dipole axis, where R/sub m/ is the planet radius. Therefore the presence of a magnetic quadrupole moment is not ruled out. The compressed dipole field more completely represents the field in the present work than in previous work where the intrinsic quadrupole field was not included in the magnetopause surface and field calculations. Moreover, we have corrected a programing error in previous work in the computation of dipole tilt lambda away from the sun. We find a slight increase for the planet dipole moment of 190γR/sub m/3 and a dipole tilt angle lambda away from the sun. We find a slight increase for the planet moment of 190γR/sub m/3 and a dipole tilt angle lambda of only 1.20 away from the sun. All other parameters are essentially unchanged

  5. Displacement cross section and DPA calculations using NMTC/JAERI

    International Nuclear Information System (INIS)

    A new function calculating displacement cross sections using the Lindhard-Robinson model is implemented in the nucleon-meson transport code NMTC/JAERI. The nucleon-nucleus cross sections in the energy region above 950 MeV and the angular distribution data of elastic scattering are also modified to evaluate the displacement cross sections as accurate as possible. The displacement cross sections of Cr, Fe Ni, and type 316 stainless steel are calculated with the updated version of NMTC/JAERI. It is confirmed that the calculated displacement cross sections caused by the elastic scattering connect smoothly with the value of the JENDL PKA File at 20 MeV. With these calculation values, the displacement per atoms (DPA) in the beam window and target vessel of a mercury target are estimated in a framework of the neutronics design study of the spallation target bombarded with 1.5 GeV protons with a power of 5 MW. The following three beam conditions are selected in this calculation; (a) uniform distribution with average current density of 48 μA/cm2, (b) parabolic distribution with average current density of 48 μA/cm2, and (c) that with average current density of 24 μA/cm2. The DPAs are estimated as (a) 68, (b) 114, and (c) 70 DPA/yr at the beam windows, and (a) 41, (b) 52, and (c) 37 DPA/yr at the target vessel for the three cases, respectively. It is found that the DPAs obtained in this study are almost the same as the results of other design studies for spallation neutron source facilities. (author)

  6. Nano-scale displacement sensing based on van der Waals interactions

    Science.gov (United States)

    Hu, Lin; Zhao, Jin; Yang, Jinlong

    2015-05-01

    We propose that a nano-scale displacement sensor with high resolution in weak-force systems can be realized based on vertically stacked two-dimensional (2D) atomic corrugated layer materials bound through van der Waals (vdW) interactions. Using first-principles calculations, we found that the electronic structures of bi-layer blue phosphorus (BLBP) vary appreciably with lateral and vertical interlayer displacements. The variation of the electronic structure is attributed to the change of the interlayer distance dz for both the lateral and vertical displacement. For lateral displacement, the change of dz is induced by atomic layer corrugation. Despite the different stacking configurations of BLBP, we find that the change of the indirect band gap is proportional to dz-2. Furthermore, this dz-2 dependence is found to be applicable to other graphene-like corrugated bi-layer materials such as MoS2. BLBP represents a large family of bi-layer 2D atomic corrugated materials for which the electronic structure is sensitive to the interlayer vertical and lateral displacement, and thus could be used for a nano-scale displacement sensor. This can be done by monitoring the tunable electronic structure using absorption spectroscopy. Because this type of sensor is established on atomic layers coupled through vdW interactions, it provides unique applications in the measurements of nano-scale displacement induced by tiny external forces.We propose that a nano-scale displacement sensor with high resolution in weak-force systems can be realized based on vertically stacked two-dimensional (2D) atomic corrugated layer materials bound through van der Waals (vdW) interactions. Using first-principles calculations, we found that the electronic structures of bi-layer blue phosphorus (BLBP) vary appreciably with lateral and vertical interlayer displacements. The variation of the electronic structure is attributed to the change of the interlayer distance dz for both the lateral and vertical

  7. Modelling toehold-mediated RNA strand displacement

    CERN Document Server

    Šulc, Petr; Romano, Flavio; Doye, Jonathan P K; Louis, Ard A

    2014-01-01

    We study the thermodynamics and kinetics of an RNA toehold-mediated strand displacement reaction with a recently developed coarse-grained model of RNA. Strand displacement, during which a single strand displaces a different strand previously bound to a complementary substrate strand, is an essential mechanism in active nucleic acid nanotechnology and has also been hypothesized to occur in vivo. We study the rate of displacement reactions as a function of the length of the toehold and temperature and make two experimentally testable predictions: that the displacement is faster if the toehold is placed at the 5' end of the substrate and that the displacement slows down with increasing temperature for longer toeholds.

  8. Rock displacements measured during URL shaft sinking

    International Nuclear Information System (INIS)

    During sinking of the Canadian Underground Research Laboratory (URL) shaft, borehole extensometers were used to obtain rock displacement measurements and a tape extensometer was used to measure total convergences. The instruments, instrument modifications, and methods used are described. The measurements are summarized and assessed, with particular emphasis on the influence of natural fractures on rock-mass response and the performance of the instrumentation. Displacements varied from 0.09 mm to 1.75 mm. The frequency of sub-vertical fractures in the rock appeared to be the main factor causing the variation in the measured displacements. Although the displacement instrumentation met certain operational requirement well, lack of precision was a problem. Displacement instrumentation used in future URL experiments should have more measuring points, greater sensitivity, and greater accuracy to better measure small displacements

  9. Preventing re-displacement through genuine reintegration in Burundi

    Directory of Open Access Journals (Sweden)

    Lucy Hovil

    2012-12-01

    Full Text Available Displacement is often part of a cyclical process of conflict anddisplacement. Preventing displacement, therefore, is not only aboutpreventing new displacement but about ensuring that people do notget re-displaced.

  10. Atom Chips

    CERN Document Server

    Folman, R; Cassettari, D; Hessmo, B; Maier, T; Schmiedmayer, J; Folman, Ron; Krüger, Peter; Cassettari, Donatella; Hessmo, Björn; Maier, Thomas

    1999-01-01

    Atoms can be trapped and guided using nano-fabricated wires on surfaces, achieving the scales required by quantum information proposals. These Atom Chips form the basis for robust and widespread applications of cold atoms ranging from atom optics to fundamental questions in mesoscopic physics, and possibly quantum information systems.

  11. Policies for Displaced Workers: An American Perspective

    OpenAIRE

    O'Leary, Christopher J.

    2009-01-01

    American employment policy for displaced workers started in the Great Depression with programs for the employment service, unemployment insurance, work experience, and direct job creation. Assistance for workers displaced by foreign competition emerged in the 1960s along with formalized programs for occupational job skill training. The policy focus on displaced workers was sharpened in the 1980s through the Worker Adjustment and Retraining Notification Act and the Economic Dislocation and Wor...

  12. Displacement speeds in turbulent premixed flame simulations

    Energy Technology Data Exchange (ETDEWEB)

    Day, Marcus S.; Shepherd, Ian G.; Bell, J.; Grcar, Joseph F.; Lijewski, Michael J.

    2007-07-01

    The theory of turbulent premixed flames is based on acharacterization of the flame as a discontinuous surface propagatingthrough the fluid. The displacement speed, defined as the local speed ofthe flame front normal to itself, relative to the unburned fluid,provides one characterization of the burning velocity. In this paper, weintroduce a geometric approach to computing displacement speed anddiscuss the efficacy of the displacement speed for characterizing aturbulent flame.

  13. Displacing AIDS: therapeutic transitions in Northern Uganda

    OpenAIRE

    Wilhelm-Solomon, M. M.; Alexander, Jocelyn; Daley, Patricia

    2014-01-01

    This doctoral project, entitled 'Displacing AIDS: Therapeutic Transitions in Northern Uganda' examines the biosocial transitions engendered by the treatment of HIV, focusing on antiretroviral therapy (ART/ARV) interventions, and the ways these are intertwined with the social transitions of conflict, displacement and return. The research involved an inter-disciplinary qualitative study with internally displaced communities living with HIV in northern Uganda, during 10 months fieldwork between ...

  14. Displacement of Propagating Squeezed Microwave States.

    Science.gov (United States)

    Fedorov, Kirill G; Zhong, L; Pogorzalek, S; Eder, P; Fischer, M; Goetz, J; Xie, E; Wulschner, F; Inomata, K; Yamamoto, T; Nakamura, Y; Di Candia, R; Las Heras, U; Sanz, M; Solano, E; Menzel, E P; Deppe, F; Marx, A; Gross, R

    2016-07-01

    Displacement of propagating quantum states of light is a fundamental operation for quantum communication. It enables fundamental studies on macroscopic quantum coherence and plays an important role in quantum teleportation protocols with continuous variables. In our experiments, we have successfully implemented this operation for propagating squeezed microwave states. We demonstrate that, even for strong displacement amplitudes, there is no degradation of the squeezing level in the reconstructed quantum states. Furthermore, we confirm that path entanglement generated by using displaced squeezed states remains constant over a wide range of the displacement power. PMID:27447495

  15. Displacement of Propagating Squeezed Microwave States

    Science.gov (United States)

    Fedorov, Kirill G.; Zhong, L.; Pogorzalek, S.; Eder, P.; Fischer, M.; Goetz, J.; Xie, E.; Wulschner, F.; Inomata, K.; Yamamoto, T.; Nakamura, Y.; Di Candia, R.; Las Heras, U.; Sanz, M.; Solano, E.; Menzel, E. P.; Deppe, F.; Marx, A.; Gross, R.

    2016-07-01

    Displacement of propagating quantum states of light is a fundamental operation for quantum communication. It enables fundamental studies on macroscopic quantum coherence and plays an important role in quantum teleportation protocols with continuous variables. In our experiments, we have successfully implemented this operation for propagating squeezed microwave states. We demonstrate that, even for strong displacement amplitudes, there is no degradation of the squeezing level in the reconstructed quantum states. Furthermore, we confirm that path entanglement generated by using displaced squeezed states remains constant over a wide range of the displacement power.

  16. Tracking speckle displacement by double Kalman filtering

    Institute of Scientific and Technical Information of China (English)

    Donghui Li; Li Guo

    2006-01-01

    @@ A tracking technique using two sequentially-connected Kalman filter for tracking laser speckle displacement is presented. One Kalman filter tracks temporal speckle displacement, while another Kalman filter tracks spatial speckle displacement. The temporal Kalman filter provides a prior for the spatial Kalman filter, and the spatial Kalman filter provides measurements for the temporal Kalman filter. The contribution of a prior to estimations of the spatial Kalman filter is analyzed. An optical analysis system was set up to verify the double-Kalman-filter tracker's ability of tracking laser speckle's constant displacement.

  17. Effects of Fault Displacement on Emplacement Drifts

    International Nuclear Information System (INIS)

    The purpose of this analysis is to evaluate potential effects of fault displacement on emplacement drifts, including drip shields and waste packages emplaced in emplacement drifts. The output from this analysis not only provides data for the evaluation of long-term drift stability but also supports the Engineered Barrier System (EBS) process model report (PMR) and Disruptive Events Report currently under development. The primary scope of this analysis includes (1) examining fault displacement effects in terms of induced stresses and displacements in the rock mass surrounding an emplacement drift and (2 ) predicting fault displacement effects on the drip shield and waste package. The magnitude of the fault displacement analyzed in this analysis bounds the mean fault displacement corresponding to an annual frequency of exceedance of 10-5 adopted for the preclosure period of the repository and also supports the postclosure performance assessment. This analysis is performed following the development plan prepared for analyzing effects of fault displacement on emplacement drifts (CRWMS M and O 2000). The analysis will begin with the identification and preparation of requirements, criteria, and inputs. A literature survey on accommodating fault displacements encountered in underground structures such as buried oil and gas pipelines will be conducted. For a given fault displacement, the least favorable scenario in term of the spatial relation of a fault to an emplacement drift is chosen, and the analysis is then performed analytically. Based on the analysis results, conclusions are made regarding the effects and consequences of fault displacement on emplacement drifts. Specifically, the analysis will discuss loads which can be induced by fault displacement on emplacement drifts, drip shield and/or waste packages during the time period of postclosure

  18. Regional resilience to displacements: Explaining the regional capacity to re-employ displaced workers

    OpenAIRE

    Nyström, Kristina

    2015-01-01

    Job displacement, which is defined as an involuntary loss of job due to economic downturns or structural changes, hit millions of workers each year. According to OECD (2013) 2-7 percent of workers are displaced every year. For Sweden, OECD (2013) reports an average displacement rate of about 2 percent for the period 2000-2008. Our knowledge on the individual consequences of displacement, in terms of, for example, unemployment duration, and earning losses is comprehensive (See e.g. Hammermesh ...

  19. Etiopathogenesis of abomasal displacement in cattle

    Directory of Open Access Journals (Sweden)

    Šamanc Horea

    2003-01-01

    Full Text Available Abomasal displacement presents topographic gastropathy, where this organ has changed its position, and there is simultaneous dilatation which can vary in intensity. The incidence of this disorder in herds of high-yield dairy cows varies to a great degree (1 to 18 %. Abomasal displacement was established in herds of East-Frisian cows in 1 to 3% animals, and in Holstein cow herds in 5 to 18 % animals. The most frequent abomasal displacement is to the left (88%. There is significant seasonal variation in the incidence of abomasal displacement. About two-thirds of cases of abomasal displacement are diagnosed from October until April. The disorder appears more frequently in cows with repeated lactations. It has been established that it appears after the first calving in 27.8% cases, after the second to fifth calving in 66.7% cases, and after the sixth and seventh calving in 5.5% of the cows. The response of endocrine pancreas B-cells for insulin secretion to hyperglycaemia caused by applying an excess-glucose test is reduced in cows with left abomasal displacement, and there is constant hyperglycaemia in cows with right abomasal displacement. The excess-glucose test indicates a disrupted function of the endocrine pancreas in diseased animals. It has been determined through examinations of Aml genotypes in Holstein cow herds in connection with the appearance of abomasal displacement, that the occurrence of this disorder cannot be attributed to a genetic predisposition.

  20. 40 CFR 205.153 - Engine displacement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Engine displacement. 205.153 Section 205.153 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a)...

  1. Video Games, Adolescents, and the Displacement Effect

    Science.gov (United States)

    Fisher, Carla Christine

    2012-01-01

    The displacement effect (the idea that time spent in one activity displaces time spent in other activities) was examined within the lens of adolescents' video game use and their time spent reading, doing homework, in physically active sports and activities, in creative play, and with parents and friends. Data were drawn from the Panel Study…

  2. Capacitive Displacement Sensor With Frequency Readout

    Science.gov (United States)

    Fritsch, Klaus

    1989-01-01

    Simple displacement-measuring circuit senses capacitance between two parallel conducting plates and produces output signal, with frequency proportional to distance between plates. Principle of circuit provides advantages over other methods because of frequency-encoded output and high linearity. Used to measure displacements.

  3. Displacement cross sections and PKA spectra: tables and applications

    International Nuclear Information System (INIS)

    Damage energy cross sections to 20 MeV are given for aluminum, vanadium, chromium, iron, nickel, copper, zirconium, niobium, molybdenum, tantalum, tungsten, lead, and 18Cr10Ni stainless steel. They are based on ENDF/B-IV nuclear data and the Lindhard energy partition model. Primary knockon atom (PKA) spectra are given for aluminum, iron, niobium, tantalum, and lead for neutron energies up to 15 MeV at approximately one-quarter lethargy intervals. The contributions of various reactions to both the displacement cross sections (taken to be proportional to the damage energy cross sections) and the PKA spectra are presented graphically. Spectral-averaged values of the displacement cross sections are given for several spectra, including approximate maps for the Experimental Breeder Reactor-II (EBR-II) and several positions in the Fast Test Reactor (FTR). Flux values are included to permit estimation of displacement rates. Graphs show integral PKA spectra for the five metals listed above for neutron spectra corresponding to locations in the EBR-II, the High Flux Isotope Reactor (HFIR), and a conceptual fusion reactor (UWMAK-I). Detailed calculations are given only for cases not previously documented. Uncertainty estimates are included

  4. Defect structures induced by high-energy displacement cascades in γ uranium

    International Nuclear Information System (INIS)

    Displacement cascade simulations were conducted for the c uranium system based on molecular dynamics. A recently developed modified embedded atom method (MEAM) potential was employed to replicate the atomic interactions while an embedded atom method (EAM) potential was adopted to help characterize the defect structures induced by the displacement cascades. The atomic displacement process was studied by providing primary knock-on atoms (PKAs) with kinetic energies from 1 keV to 50 keV. The influence of the PKA incident direction was examined. The defect structures were analyzed after the systems were fully relaxed. The states of the self-interstitial atoms (SIAs) were categorized into various types of dumbbells, the crowdion, and the octahedral interstitial. The voids were determined to have a polyhedral shape with facets. The size distribution of the voids was also obtained. The results of this study not only expand the knowledge of the microstructural evolution in irradiated c uranium, but also provide valuable references for the radiation-induced defects in uranium alloy fuels.

  5. Helium and displacement damage produced by 600 MeV proton beams in high purity aluminum

    International Nuclear Information System (INIS)

    Pure aluminum samples (99.9999%) have been irradiated in the Proton Irradiation Experiment (PIREX) installed in the 600 MeV proton beam of the accelerator in the Swiss Nuclear Research Institute (SIN), at temperatures between 400K and 500K and displacement doses between 0.9 and 5 displacements per atom (dpa). Average displacement rate is 3.5 X 10-6 dpa/s. The specimens were analyzed for both 3He and 4He. Measured helium content is 215 atomic parts per million (appm)/dpa. No diffusional spreading of sodium or helium was measured. The helium bubble structure was examined and shows a swelling of 0.16% at about5 dpa

  6. Kirchhoff plate theory-based electromechanically-coupled analytical model considering inertia and stiffness effects of a surface-bonded piezoelectric patch

    Science.gov (United States)

    Yoon, Heonjun; Youn, Byeng D.; Kim, Heung Soo

    2016-02-01

    As a compact and durable design concept, piezoelectric energy harvesting skin (PEH skin) has been recently proposed for self-powered electronic device applications. This study aims to develop an electromechanically-coupled analytical model of PEH skin considering the inertia and stiffness effects of a piezoelectric patch. Based on Kirchhoff plate theory, Hamilton’s principle is used to derive the electromechanically-coupled differential equation of motion. Due to the geometric discontinuity of the piezoelectric patch, the Rayleigh-Ritz method is applied to calculate the natural frequency and corresponding mode shapes. The electrical circuit equation is derived from Gauss’s law. Output voltage is estimated by solving the equation of motion and electrical circuit equation, simultaneously. For the purpose of evaluating the predictive capability, the results of the electromechanically-coupled analytical model are compared with those of the finite element method in a hierarchical manner. The outstanding merits of the electromechanically-coupled analytical model of PEH skin are three-fold: (1) consideration of the inertia and stiffness effects of the piezoelectric patches; (2) physical parameterization between the two-dimensional mechanical configuration and piezoelectric transduction; (3) manipulability of the twisting modes of a cantilever plate with a small aspect ratio.

  7. Elimination of a Second-Law-Attack, and All Cable-Resistance-Based Attacks, in the Kirchhoff-Law-Johnson-Noise (KLJN Secure Key Exchange System

    Directory of Open Access Journals (Sweden)

    Laszlo B. Kish

    2014-10-01

    Full Text Available We introduce the so far most efficient attack against the Kirchhoff-law-Johnson-noise (KLJN secure key exchange system. This attack utilizes the lack of exact thermal equilibrium in practical applications and is based on cable resistance losses and the fact that the Second Law of Thermodynamics cannot provide full security when such losses are present. The new attack does not challenge the unconditional security of the KLJN scheme, but it puts more stringent demands on the security/privacy enhancing protocol than for any earlier attack. In this paper we present a simple defense protocol to fully eliminate this new attack by increasing the noise-temperature at the side of the smaller resistance value over the noise-temperature at the side with the greater resistance. It is shown that this simple protocol totally removes Eve’s information not only for the new attack but also for the old Bergou-Scheuer-Yariv attack. The presently most efficient attacks against the KLJN scheme are thereby completely nullified.

  8. Johnson(-like)-Noise-Kirchhoff-loop based secure classical communicator characteristics, for ranges of two to two thousand kilometers, via model-line

    International Nuclear Information System (INIS)

    A pair of Kirchhoff-loop-Johnson(-like)-Noise communicators, which is able to work over variable ranges, was designed and built. Tests have been carried out on a model-line performance characteristics were obtained for ranges beyond the ranges of any known direct quantum communication channel and they indicate unrivalled signal fidelity and security performance of the exchanged raw key bits. This simple device has single-wire secure key generation and sharing rates of 0.1, 1, 10, and 100 bit/second for corresponding copper wire diameters/ranges of 21 mm/2000 km, 7 mm/200 km, 2.3 mm/20 km, and 0.7 mm/2 km, respectively and it performs with 0.02% raw-bit error rate (99.98% fidelity). The raw-bit security of this practical system significantly outperforms raw-bit quantum security. Current injection breaking tests show zero bit eavesdropping ability without triggering the alarm signal, therefore no multiple measurements are needed to build an error statistics to detect the eavesdropping as in quantum communication. Wire resistance based breaking tests of Bergou-Scheuer-Yariv type give an upper limit of eavesdropped raw-bit ratio of 0.19% and this limit is inversely proportional to the sixth power of cable diameter. Hao's breaking method yields zero (below measurement resolution) eavesdropping information

  9. Atomic energy

    CERN Multimedia

    1996-01-01

    Interviews following the 1991 co-operation Agreement between the Department of Atomic Energy (DAE) of the Government of India and the European Organization for Nuclear Research (CERN) concerning the participation in the Large Hadron Collider Project (LHC) . With Chidambaram, R, Chairman, Atomic Energy Commission and Secretary, Department of Atomic Energy, Department of Atomic Energy (DAE) of the Government of India and Professor Llewellyn-Smith, Christopher H, Director-General, CERN.

  10. Atom chips

    CERN Document Server

    Reichel, Jakob

    2010-01-01

    This book provides a stimulating and multifaceted picture of a rapidly developing field. The first part reviews fundamentals of atom chip research in tutorial style, while subsequent parts focus on the topics of atom-surface interaction, coherence on atom chips, and possible future directions of atom chip research. The articles are written by leading researchers in the field in their characteristic and individual styles.

  11. Rotor Displacement of the Ultrasonic Motor Having an Angular Displacement Self-Correction Function

    Science.gov (United States)

    Chen, Xiaoduo; Kusakabe, Chiharu; Tomikawa, Yoshiro; Takano, Takehiro

    1993-09-01

    This paper deals with the experimental investigation for confirmation of rotor displacement of the ultrasonic stepping motor having an angular displacement self-correction function. The experiment focused on the relationship between the rotor’s vibration displacement and its staying position for the self-correction. The result proved that the rotor always stays at the position where the displacement is smallest by cutting a slit into the rotor. Moreover, it has also been found that the stable self-correction of rotor angular displacement depends upon both the rotor driving frequency and rotor clamping force.

  12. Atomic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Safronova, M. S. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Mitroy, J. [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Clark, Charles W. [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, Maryland 20899-8410 (United States); Kozlov, M. G. [Petersburg Nuclear Physics Institute, Gatchina 188300 (Russian Federation)

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  13. Atomic Physics

    CERN Document Server

    Foot, Christopher J

    2007-01-01

    This text will thoroughly update the existing literature on atomic physics. Intended to accompany an advanced undergraduate course in atomic physics, the book will lead the students up to the latest advances and the applications to Bose-Einstein Condensation of atoms, matter-wave inter-ferometry and quantum computing with trapped ions. The elementary atomic physics covered in the early chapters should be accessible to undergraduates when they are first introduced to the subject. To complement. the usual quantum mechanical treatment of atomic structure the book strongly emphasizes the experimen

  14. Atomic polarizabilities

    International Nuclear Information System (INIS)

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed

  15. Atom interferometry

    International Nuclear Information System (INIS)

    We will first present a development of the fundamental principles of atom interferometers. Next we will discuss a few of the various methods now available to split and recombine atomic De Broglie waves, with special emphasis on atom interferometers based on optical pulses. We will also be particularly concerned with high precision interferometers with long measurement times such those made with atomic fountains. The application of atom interferometry to the measurement of the acceleration due to gravity will be detailed. We will also develop the atom interferometry based on adiabatic transfer and we will apply it to the measurement of the photon recoil in the case of the Doppler shift of an atomic resonance caused by the momentum recoil from an absorbed photon. Finally the outlook of future developments will be given. (A.C.)

  16. Defects and threshold displacement energies in SrTiO3 perovskite using atomistic computer simulations

    International Nuclear Information System (INIS)

    The mode and energy of simple defect incorporation in SrTiO3 (vacancies and interstitials) is quantified using computer simulation techniques with an empirical partial charge model of interatomic forces, as well as using density functional theory calculations. Oxygen and strontium interstitials form split-interstitial configurations whereas titanium interstitials occupy channel positions. Defect migration energies and paths are also considered; interstitials are more mobile than vacancies, with a low predicted oxygen interstitial migration energy of around 0.3 eV. We also calculate the threshold displacement energy (Ed) for each atom type in SrTiO3 perovskite using molecular dynamics simulations, by introducing a primary knock-on atom with a range of energies (20-250 eV) in principal crystallographic directions at 300 K. We find that all atom types are most easily displaced via direct replacement sequences on their own sublattices, which are extensive for Sr atoms due to focusson processes acting along channels. The weighted average threshold displacement energies (for use in TRIM-type calculations) are 50 eV for oxygen, 70 eV for strontium and 140 eV for titanium atoms. These computed energies for O and Sr are comparable to experimentally-derived values in perovskites, whereas the Ed for Ti is much higher; it is expected that the value reported here is more accurate due to experimental difficulties in distinguishing different types of defects

  17. Epitaxial growth by monolayer restricted galvanic displacement

    Directory of Open Access Journals (Sweden)

    Vasilić Rastko

    2012-01-01

    Full Text Available The development of a new method for epitaxial growth of metals in solution by galvanic displacement of layers pre-deposited by underpotential deposition (UPD was discussed and experimentally illustrated throughout the lecture. Cyclic voltammetry (CV and scanning tunneling microscopy (STM are employed to carry out and monitor a “quasi-perfect”, two-dimensional growth of Ag on Au(111, Cu on Ag(111, and Cu on Au(111 by repetitive galvanic displacement of underpotentially deposited monolayers. A comparative study emphasizes the displacement stoichiometry as an efficient tool for thickness control during the deposition process and as a key parameter that affects the deposit morphology. The excellent quality of layers deposited by monolayer-restricted galvanic displacement is manifested by a steady UPD voltammetry and ascertained by a flat and uniform surface morphology maintained during the entire growth process.

  18. Making work safe for displaced women

    Directory of Open Access Journals (Sweden)

    Dale Buscher

    2012-12-01

    Full Text Available Displaced women need opportunities to make a living for themselves and their families but these opportunities should not increase their vulnerability. Understanding risk factors and protection strategies allows practitioners to ensure appropriate programme design and implementation.

  19. A flexible sensor measuring displacement and bending

    Science.gov (United States)

    Nishijima, Takashi; Yamamoto, Akio; Higuchi, Toshiro

    2009-04-01

    This paper proposes a new sensor that is capable of measuring both linear displacement and bending. The sensor is designed to be used with an electrostatic film motor that features mechanical flexibility, but can also be used as an independent sensor. The sensor employs three-phase electrodes both in sliding and stationary parts and estimates displacement and bending from the change of the capacitance between the electrodes. The paper describes an equivalent capacitance-network model for the sensor. Based on the model, sensing principles for both displacement and bending are presented and analyzed. The analyses are experimentally verified using a prototype sensor. The experimental results show that the prototype sensor could measure both displacement and bending with little interference between them.

  20. Precision optical displacement measurements using biphotons

    OpenAIRE

    Lyons, Kevin; Pang, Shengshi; Kwiat, Paul G.; Jordan, Andrew N

    2016-01-01

    We propose and examine the use of biphoton pairs, such as those created in parametric down conversion or four-wave mixing, to enhance the precision and the resolution of measuring optical displacements by position-sensitive detection. We show that the precision of measuring a small optical beam displacement with this method can be significantly enhanced by the correlation between the two photons, given the same optical mode. The improvement is largest if the correlations between the photons a...

  1. Realization of atomic GHZ states via cavity QED

    International Nuclear Information System (INIS)

    In this work we propose a scheme in which it is possible to generate atomic GHZ states by letting three-level atoms in a lambda configuration to interact with a cavity field followed by a displacement of the cavity field and a selective measurements on two-level atoms which disentangle the atoms and field states. We also propose a GHZ test based on such states. (author)

  2. A Re-examination of Kirchhoff's Law of Thermal Radiation in Relation to Recent Criticisms: Reply (Letters to Progress in Physics

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2016-07-01

    Full Text Available Recently, Robert J. Johnson submitted an analysis of my work, relative to Kirchhoff’s Law of Thermal Emission (R.J. Johnson, A Re-examination of Kirchhoff’s Law of Thermal Radiation in Relation to Recent Criticisms. Prog. Phys. , 2016, v.12, no.3, 175–183 in which he reached the conclusion that “Robitaille’s claims are not sus- tainable and that Kirchhoff’s Law and Planck’s proof remain valid in the situations for which they were intended to apply, including in cavities with walls of any arbi- trary materials in thermal equilibrium” . However, even a cursory review of Johnson’s letter reveals that his conclusions are unjustified. No section constitutes a proper chal- lenge to my writings. Nonetheless, his letter is important, as it serves to underscore the impossibility of defending Kirchhoff’s work. At the onset, Kirchhoff formulated his law, based solely on thought experiments and, without an y experimental evidence (G. Kirchhoff, ̈Uber das Verh ̈altnis zwischen dem Emissionsverm ̈ogen und dem Ab- sorptionsvermogen. der K ̈orper fur W ̈arme und Licht. Pogg. Ann. Phys. Chem. , 1860, v. 109, 275–301. Thought experiments, not laboratory confirmation, remain the ba- sis on which Kirchhoff’s law is defended, despite the passage of 150 years. For his part, Max Planck tried to derive Kirchhoff’s Law by redefining the nature of a black body and relying on the use of polarized radiation, even though he realized that heat radiation is never polarized (Planck M. The Theory of Heat radiation . P.Blakiston’s Son & Co., Philadelphia, PA, 1914. In advancing his proof of Kirchhoff’s Law, Max Planck concluded that the reflectivities of any two arbitrary materials must be equal, though he argued otherwise (see P.-M. Robitaille and S.J. Cr others, “The Theory of Heat Radiation” Revisited: A Commentary on the Validity of Kirchhoff’s Law of Ther- mal Emission and Max Planck’s Claim of Universality. Prog. Phys., 2015, v

  3. Schroedinger atom

    International Nuclear Information System (INIS)

    Features of an electrodynamical interpretation suggested by Schroedinger for the wave function are discribed. According to this conception electron charges are continuously distributed all over the volume of an atomic system. The proof is given that classical electrodynamics keeps its action inside atom. Schroedinger's atom has been shown to be the only model in which electrones do not lose their energy for emission when they move around nucleus. A significance of the distributed electron charge self-field is estimated. Practical applications of this conception have been noted including the new trend in quantum electrodynamics. Experimental and theoretical corroborations of the atom model with a continuous electron charge are adduced

  4. Atomic physics

    International Nuclear Information System (INIS)

    Research activities in atomic physics at Lawrence Berkeley Laboratory during 1976 are described. Topics covered include: experiments on stored ions; test for parity violation in neutral weak currents; energy conservation and astrophysics; atomic absorption spectroscopy, atomic and molecular detectors; theoretical studies of quantum electrodynamics and high-z ions; atomic beam magnetic resonance; radiative decay from the 23Po,2 levels of helium-like argon; quenching of the metastable 2S/sub 1/2/ state of hydrogen-like argon in an external electric field; and lifetime of the 23Po level of helium-like krypton

  5. Critical analysis of the Bennett-Riedel attack on secure cryptographic key distributions via the Kirchhoff-Law-Johnson-noise scheme.

    Directory of Open Access Journals (Sweden)

    Laszlo B Kish

    Full Text Available Recently, Bennett and Riedel (BR (http://arxiv.org/abs/1303.7435v1 argued that thermodynamics is not essential in the Kirchhoff-law-Johnson-noise (KLJN classical physical cryptographic exchange method in an effort to disprove the security of the KLJN scheme. They attempted to demonstrate this by introducing a dissipation-free deterministic key exchange method with two batteries and two switches. In the present paper, we first show that BR's scheme is unphysical and that some elements of its assumptions violate basic protocols of secure communication. All our analyses are based on a technically unlimited Eve with infinitely accurate and fast measurements limited only by the laws of physics and statistics. For non-ideal situations and at active (invasive attacks, the uncertainly principle between measurement duration and statistical errors makes it impossible for Eve to extract the key regardless of the accuracy or speed of her measurements. To show that thermodynamics and noise are essential for the security, we crack the BR system with 100% success via passive attacks, in ten different ways, and demonstrate that the same cracking methods do not function for the KLJN scheme that employs Johnson noise to provide security underpinned by the Second Law of Thermodynamics. We also present a critical analysis of some other claims by BR; for example, we prove that their equations for describing zero security do not apply to the KLJN scheme. Finally we give mathematical security proofs for each BR-attack against the KLJN scheme and conclude that the information theoretic (unconditional security of the KLJN method has not been successfully challenged.

  6. Displaced and non-displaced Colombian children's evaluations of moral transgressions, retaliation, and reconciliation

    OpenAIRE

    Ardila-Rey, Alicia; Killen, Melanie; Brenick, Alaina

    2009-01-01

    In order to assess the effects of displacement and exposure to violence on children's moral reasoning, Colombian children exposed to minimal violence (non-displaced or low-risk) (N = 99) and to extreme violence (displaced or high-risk) (N = 94), evenly divided by gender, at 6-, 9-, and 12 - years of age, were interviewed regarding their evaluation of peer-oriented moral transgressions (hitting and not sharing toys). The vast majority of children evaluated moral transgressions as wrong. Group ...

  7. Measured displacement energies for oxygen ions in perovskite structured materials

    International Nuclear Information System (INIS)

    Full text: Perovskite, CaTiO3, is a key phase in some varieties of Synroc, a family of titanate ceramics designed for high-level radioactive waste immobilisation. The waste contains actinide ions, which when incorporated in the crystalline Synroc give rise to lattice damage, primarily from the alpha-recoil nucleus of mass ∼ 240 amu and energy ∼ 100 keV. Approximately 1500 atoms are displaced in each event. Hence perovskite (and other phases) in Synroc is prone to structural disordering from radiation damage. These effects have been evidenced in X-ray diffraction and leaching studies of Synroc doped with the short-lived actinide emitters Cm-244 and Pu-238. Lattice damage effects have also been observed in heavy-ion irradiation of perovskite, using TEM to observe a variety of ion tracks and cluster phenomena, as well as the effects of irradiation temperature and post-irradiation annealing. However there is still no information on the identity of the radiation-induced fundamental point defects in CaTiO3. These defects will be the precursors of the massive structural damage observed by microscopy. The present study addresses this problem in the alkaline earth titanates. The sample was irradiated with fast electrons (0.2 MeV to 0.6 MeV) and the ultraviolet/visible fluorescence from the produced defects was monitored by time resolved emission spectroscopy. Optical emission spectra in the 300-700 nm range were collected from single crystal CaTiO3, SrTiO3 BaTiO3 and polycrystalline CaTiO3 samples that were irradiated using a Febetron 706 variable energy pulsed electron beam generator. The long-lived emissions (up to microseconds after the electron pulse) consist of broad (half widths ∼ 100 nm) bands centred around 380, 425, and 445 nm for CaTiO3, SrTiO3 and BaTiO3 respectively. These emission bands are similar to cathodoluminescence emissions from 25 keV electron irradiation attributed by others to direct conduction-valence band transitions in unreduced samples and

  8. Atomic physics

    CERN Document Server

    Born, Max

    1989-01-01

    The Nobel Laureate's brilliant exposition of the kinetic theory of gases, elementary particles, the nuclear atom, wave-corpuscles, atomic structure and spectral lines, electron spin and Pauli's principle, quantum statistics, molecular structure and nuclear physics. Over 40 appendices, a bibliography, numerous figures and graphs.

  9. Hybrid atom-membrane optomechanics

    Directory of Open Access Journals (Sweden)

    Korppi Maria

    2013-08-01

    Full Text Available We report on the realization of a hybrid optomechanical system in which ultracold atoms are coupled to a micromechanical membrane. The atoms are trapped in the intensity maxima of an optical standing wave formed by retroreflection of a laser beam from the membrane surface. Vibrations of the membrane displace the standing wave, thus coupling to the center-of-mass motion of the atomic ensemble. Conversely, atoms imprint their motion onto the laser light, thereby modulating the radiation pressure force on the membrane. In this way, the laser light mediates a long-distance coherent coupling between the two systems. When the trap frequency of the atoms is matched to the membrane frequency, we observe resonant energy transfer. Moreover, we demonstrate sympathetic damping of the membrane motion by coupling it to laser-cooled atoms. Theoretical investigations show that the coupling strength can be considerably enhanced by placing the membrane inside an optical cavity. This could lead to quantum coherent coupling and ground-state cooling of the membrane via a distant atomic ensemble.

  10. Quantification of the vocal folds’ dynamic displacements

    Science.gov (United States)

    del Socorro Hernández-Montes, María; Muñoz, Silvino; De La Torre, Manuel; Flores, Mauricio; Pérez, Carlos; Mendoza-Santoyo, Fernando

    2016-05-01

    Fast dynamic data acquisition techniques are required to investigate the motional behavior of the vocal folds (VFs) when they are subjected to a steady air-flow through the trachea. High-speed digital holographic interferometry (DHI) is a non-invasive full-field-of-view technique that has proved its usefulness to study rapid and non-repetitive object movements. Hence it is an ideal technique used here to measure VF displacements and vibration patterns at 2000 fps. Analyses from a set of 200 displacement images showed that VFs’ vibration cycles are established along their width (y) and length (x). Furthermore, the maximum deformation for the right and left VFs’ area may be quantified from these images, which in itself represents an important result in the characterization of this structure. At a controlled air pressure, VF displacements fall within the range ~100-1740 nm, with a calculated precision and accuracy that yields a variation coefficient of 1.91%. High-speed acquisition of full-field images of VFs and their displacement quantification are on their own significant data in the study of their functional and physiological behavior since voice quality and production depend on how they vibrate, i.e. their displacement amplitude and frequency. Additionally, the use of high speed DHI avoids prolonged examinations and represents a significant scientific and technological alternative contribution in advancing the knowledge and working mechanisms of these tissues.

  11. Point-defect and threshold displacement energies in Ni3Al: Pt. 2

    International Nuclear Information System (INIS)

    Molecular dynamics simulations have been employed to investigate the displacement threshold energy Ed at 0 K and the defect structure created at the displacement threshold in the ordered alloy Ni3Al. Ed for Al is generally higher and has a much stronger orientation dependence than in pure Al. For Ni recoils, however, Ed is similar to that in pure Ni in directions where Ni-Al interactions are not strong; exceptions occur along closely packed directions, for which replacement collision sequences (RCSs) are comparatively short in the ordered alloy. There are significant differences from pure Ni for directions where the Ni primary recoil makes close contact with an Al neighbour. The stable defect arrangement in Ni3Al is usually much more complex than for pure metals because of the requirements of stoichiometry and the fact that six basic defect types can occur in the alloy. Generally, however, defects on the Ni sublattices are the majority species. The principal exception to this occurs for recoils along mixed Ni-Al-Ni-Al-... rows, for which RCSs generate chains of antisite defects. These break, however, to create two Frenkel pairs for each primary recoil atom. These results are discussed in terms of structure and atomic interactions and illustrated by computer-generated defect plots. Calculations for pure Ni and Al also show that Ed is strongly influenced by the number of atoms displaced by the recoil atom and the extent to which RCSs are a feature of the defect structure. (author)

  12. Forced displacement and women's security in Colombia.

    Science.gov (United States)

    Meertens, Donny

    2010-04-01

    In the protracted Colombian conflict, assistance to internally displaced persons has developed in the context of contradictory political processes. The Colombian government's launching of a transitional justice process in the midst of armed conflict has generated a complex situation displaying both conflict and post-conflict characteristics. The progressive Constitutional Court rulings on internal displacement, in particular the gender-sensitive Auto 092, constitute an attempt to bring together humanitarian interventions and transitional justice measures in a rights-based framework. However, the national government is reluctant to adopt them fully and local realities still hamper their integrated implementation. Displaced women, therefore, remain in an especially vulnerable position. This paper argues that gender-sensitive humanitarian interventions must take into account all of these complexities of scale and political process in order to make legal frameworks more effective at the local level. In these contexts, interventions should pay particular attention to strategies that contribute to transforming pre-existing gender regimes. PMID:20132270

  13. Imaging of small radioactive point source displacement

    International Nuclear Information System (INIS)

    A new technique for three dimensional recording of a patient mandibular movement is described. A small and harmless radioactive source is fixed at the point of interest. Using proper collimation, the motion of the point source is recorded via a gamma camera and minicomputer. Image enhancement techniques are used and physiological displacement is reproduced. We measured the vertical, lateral and protrusive envelopes of motion of a point on a tooth from a full denture set mounted on a semiadjustable articulator. All displacements were calibrated. Multiple sources in a single experiment may be recorded to describe the displacement of several points of interest. First experiments were run on patients. This method, derived from Nuclear Medicine techniques, offers a powerful tool of general interest for the tracking of dynamic events in many fields of Dental Medicine, for instance temporo-mandibular joint disfunction as well as Prosthetics. (author)

  14. Performance of displacement ventilation in practice

    DEFF Research Database (Denmark)

    Naidenov, K.; Pitchurov, G.; Langkilde, Gunnar;

    2002-01-01

    the major local discomfort in the rooms with displacement ventilation. Twenty-three percent of the occupants were daily bothered by draught. In some buildings the maintenance personnel tried to improve occupants´ thermal comfort by raising the supply air temperature or office workers themselves......This paper presents results of a field study in offices with displacement ventilation. It comprises detailed physical measurements of the thermal environment and collection of occupants´ response at 227 workplaces. The results, both physical measurements and human response, identified draught as...... blocked the diffusers by rearranging the furniture. Half of the surveyed occupants were not satisfied with the indoor air quality. The main conclusion is that displacement ventilation needs careful design and room furnishing in order to ensure a comfortable environment. Occupants must understand the...

  15. DNA fork displacement rates in human cells

    International Nuclear Information System (INIS)

    DNA fork displacement rates were measured in 20 human cell lines by a bromodeoxyuridine-313 nm photolysis technique. Cell lines included representatives of normal diploid, Fanconi's anemia, ataxia telangiectasia, xeroderma pigmentosum, trisomy-21 and several transformed lines. The average value for all the cell lines was 0.53 +- 0.08 μm/min. The average value for individual cell lines, however, displayed a 30% variation. Less than 10% of variation in the fork displacement rate appears to be due to the experimental technique; the remainder is probably due to true variation among the cell types and to culture conditions. (Auth.)

  16. Bucket Foundation Response Under Various Displacement Rates

    DEFF Research Database (Denmark)

    Vaitkunaite, Evelina; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2016-01-01

    The present testing program aims at showing the pore pressure response around a bucket foundation skirt as well as the load and displacement change due to ten different displacement rates. Research findings are useful for a numerical model calibration focusing on the design of the upwind foundation...... in a multi-bucket foundation system. The foundation model is at a scale of approximately 1:20 prototype foundation size. The tests are performed in a pressure tank with the foundation model installed in dense sand. Based on the data, the conclusion is that the bucket foundation design in a storm case...

  17. Field measurement of relative ground displacement

    International Nuclear Information System (INIS)

    Protection of existing structures is a major requirement during underground nuclear blasts detonated as part of the Plowshare Program. Instrumental arrays to record ground motion are routinely established prior to blasts. These provide data on particle motions during the event but do not provide direct information concerning ground strains and relative displacements which may effect bridges, buildings, irrigation channels and other structures with large plan dimension. An experimental technique which was hastily developed and deployed to measure relative displacements during the Rio Blanco event of May 17, 1973 is described. The work was performed in anticipation of the Project Wagon Wheel in an area of Wyoming with many concrete lined irrigation channels

  18. Strain-displacement relations for strain engineering in single-layer 2d materials

    Science.gov (United States)

    Midtvedt, Daniel; Lewenkopf, Caio H.; Croy, Alexander

    2016-03-01

    We investigate the electromechanical coupling in single-layer 2d materials. For non-Bravais lattices, we find important corrections to the standard macroscopic strain-microscopic atomic-displacement theory. We put forward a general and systematic approach to calculate strain-displacement relations for several classes of 2d materials. We apply our findings to graphene as a study case, by combining a tight binding and a valence force-field model to calculate electronic and mechanical properties of graphene nanoribbons under strain. The results show good agreement with the predictions of the Dirac equation coupled to continuum mechanics. For this long wave-limit effective theory, we find that the strain-displacement relations lead to a renormalization correction to the strain-induced pseudo-magnetic fields. A similar renormalization is found for the strain-induced band-gap of black phosphorous. Implications for nanomechanical properties and electromechanical coupling in 2d materials are discussed.

  19. Investigation of an isothermal Mach 0.75 jet and its radiated sound using large-eddy simulation and Kirchhoff surface integration

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, N.; Davidson, L. [Chalmers Univ. of Technology, Goeteborg (Sweden). Division of Thermo and Fluid Dynamics; Eriksson, L.E. [Chalmers Univ. of Technology, Goeteborg (Sweden). Division of Thermo and Fluid Dynamics; Volvo Aero Vorp., Trollhaettan (Sweden)

    2005-06-01

    A large-eddy simulation (LES) of a compressible nozzle/jet configuration has been carried out. An isothermal Mach 0.75 jet was simulated. The Reynolds number based on the jet velocity at the nozzle exit plane and the nozzle diameter was 5.0x10{sup 4}. The Favre filtered Navier-Stokes equations were solved using a finite volume method solver with a low-dissipation third-order upwind scheme for the convective fluxes, a second-order centered difference approach for the viscous fluxes and a three-stage second-order Runge-Kutta time marching technique. A compressible form of Smagorinsky's subgrid scale model was used for computation of the subgrid scale stresses. The computational domain was discretized using a block structured boundary fitted mesh with approximately 3.0x10{sup 6} cells. The calculations were performed on a parallel computer, using message-passing interface (MPI). Absorbing boundary conditions based on characteristic variables were adopted for all free boundaries. Velocity components specified at the entrainment boundaries were estimated from a corresponding Reynolds averaged Navier-Stokes (RANS) calculation, which enabled the use of a rather narrow domain. In order to diminish disturbances caused by the outlet boundary, a buffer layer was added at the domain outlet. Kirchhoff surface integration using instantaneous pressure data from the LES was utilized to obtain far-field sound pressure levels in a number of observer locations. The predicted sound pressure levels were for all observer locations within a 3 dB deviation from the measured levels and for most observer locations within a 1 dB deviation. Aerodynamic results and predicted sound pressure levels are both in good agreement with experiments. Experimental data were provided by Laboratoire d'Etude Aerodynamiques, Poitiers, France [Jordan, P., Gervais, Y., Valiere, J.-C., Foulon, H., 2002. Final results from single point measurements. Project deliverable D3.4, JEAN-EU 5th Framework

  20. Investigation of an isothermal Mach 0.75 jet and its radiated sound using large-eddy simulation and Kirchhoff surface integration

    International Nuclear Information System (INIS)

    A large-eddy simulation (LES) of a compressible nozzle/jet configuration has been carried out. An isothermal Mach 0.75 jet was simulated. The Reynolds number based on the jet velocity at the nozzle exit plane and the nozzle diameter was 5.0 x 104. The Favre filtered Navier-Stokes equations were solved using a finite volume method solver with a low-dissipation third-order upwind scheme for the convective fluxes, a second-order centered difference approach for the viscous fluxes and a three-stage second-order Runge-Kutta time marching technique. A compressible form of Smagorinsky's subgrid scale model was used for computation of the subgrid scale stresses. The computational domain was discretized using a block structured boundary fitted mesh with approximately 3.0 x 106 cells. The calculations were performed on a parallel computer, using message-passing interface (MPI). Absorbing boundary conditions based on characteristic variables were adopted for all free boundaries. Velocity components specified at the entrainment boundaries were estimated from a corresponding Reynolds averaged Navier-Stokes (RANS) calculation, which enabled the use of a rather narrow domain. In order to diminish disturbances caused by the outlet boundary, a buffer layer was added at the domain outlet. Kirchhoff surface integration using instantaneous pressure data from the LES was utilized to obtain far-field sound pressure levels in a number of observer locations. The predicted sound pressure levels were for all observer locations within a 3 dB deviation from the measured levels and for most observer locations within a 1 dB deviation. Aerodynamic results and predicted sound pressure levels are both in good agreement with experiments. Experimental data were provided by Laboratoire d'Etude Aerodynamiques, Poitiers, France [Jordan, P., Gervais, Y., Valiere, J.-C., Foulon, H., 2002. Final results from single point measurements. Project deliverable D3.4, JEAN-EU 5th Framework Programme, G4RD-CT2000

  1. A Simple Condition for Bounded Displacement

    CERN Document Server

    Solomon, Yaar

    2011-01-01

    We study separated nets that correspond to substitution tilings of the Euclidean space. We give a simple condition, in terms of the eigenvalues and eigenspaces of the substitution matrix, to know whether the separated net is a bounded displacement of the integer lattice or not.

  2. Nonlinear Brownian motion - mean square displacement

    Directory of Open Access Journals (Sweden)

    W.Ebeling

    2004-01-01

    Full Text Available The stochastic dynamics of self-propelled Brownian particles is studied by means of the Langevin and the Fokker-Planck approach. We model the driving by a nonlinear friction function which has a negative part at small velocities, leading to active Brownian motion of the particles. The mean square displacement is estimated analytically and compared with numerical simulations.

  3. Education: protecting the rights of displaced children

    Directory of Open Access Journals (Sweden)

    Suba Mahalingam

    2002-10-01

    Full Text Available UNICEF and its partners work with displaced communitiesto provide material assistance and protection, using as their basis the UN Convention on the Rights of the Child1 and other internationallegal instruments. Education has proven a valuable tool in this effort, not only making children aware of their rights but also providing a way to participate in the realisation of these rights.

  4. Wien's Displacement Law in Rindler Space

    CERN Document Server

    De, Sanchari; Ghosh, Sutapa; Chakrabarty, Somenath

    2015-01-01

    In this article we have developed a formalism to obtained the modified form of Wien's displacement law when the wall of the enclosure containing a photon gas is expanding adiabatically with a uniform acceleration. We have also studied the gravitational redshift of photons inside the enclosure using the prescription of extended relativistic dynamics with an upper limit of acceleration.

  5. Displacement Damage in Bipolar Linear Integrated Circuits

    Science.gov (United States)

    Rax, B. G.; Johnston, A. H.; Miyahira, T.

    2000-01-01

    Although many different processes can be used to manufacture linear integrated circuits, the process that is used for most circuits is optimized for high voltage -- a total power supply voltage of about 40 V -- and low cost. This process, which has changed little during the last twenty years, uses lateral and substrate p-n-p transistors. These p-n-p transistors have very wide base regions, increasing their sensitivity to displacement damage from electrons and protons. Although displacement damage effects can be easily treated for individual transistors, the net effect on linear circuits can be far more complex because circuit operation often depends on the interaction of several internal transistors. Note also that some circuits are made with more advanced processes with much narrower base widths. Devices fabricated with these newer processes are not expected to be significantly affected by displacement damage for proton fluences below 1 x 10(exp 12) p/sq cm. This paper discusses displacement damage in linear integrated circuits with more complex failure modes than those exhibited by simpler devices, such as the LM111 comparator, where the dominant response mode is gain degradation of the input transistor. Some circuits fail catastrophically at much lower equivalent total dose levels compared to tests with gamma rays. The device works satisfactorily up to nearly 1 Mrad(Si) when it is irradiated with gamma rays, but fails catastrophically between 50 and 70 krad(Si) when it is irradiated with protons.

  6. Passive Smoking in a Displacement Ventilated Room

    DEFF Research Database (Denmark)

    Bjørn, Erik; Nielsen, Peter V.

    The aim of this research is to see if the displacement ventilation principle can protect a person from exposure to passive tobacco smoking. This is done by full-scale experiments with two breathing thermal manikins, smoke visualisations, and tracer gas measurements. In some situations, exhaled sm...... convective boundary layer flow around the body....

  7. Calculation of Gamma Displacement Cross Sections: Generation of Recoil Spectra from ENDF/B-VII

    International Nuclear Information System (INIS)

    Radiation damage in materials is caused by the transfer of energy from an incident particle to the target atoms, which results in the redistribution of target atoms. During the nuclear reactor operation, various kinds of radiation are produced, including fast neutron, gamma, beta, high-energy ions etc. These radiations may affect the properties of reactor structural materials in a direct and/or indirect way. It is well known that fast neutrons have an effect on the degradation of materials. Whereas the impact of fast neutrons (En > 1 MeV) on material property changes is clearly recognized, the impact of gamma ray damage to materials is usually not significant. However, there has been some interest in gamma ray damage in metals in promoting accelerated embrittlement of reactor pressure vessel steels in the HFIR (High Flux Isotopes Reactor). In situations where there is a large water gap between pressure vessel and fuel assembly, gamma damage can become comparable to that produced by neutrons, on the basis of displacements per atom (dpa) parameter. A recent analysis of gamma ray displacement damage in the RPV of the General Electric Advanced Boiling Water Reactor (ABWR) indicated that the ratio of calculated gamma- to neutron-induced displacement damage rates is over 100% at the RPV inner diameter. Under a high gamma dose environment, embrittlement can be accelerated by radiation-enhanced mass transport mechanism. Because gamma rays are much more efficient than neutrons at producing freely-migrating defects, any radiation enhanced or induced processes that depend on the magnitude of defect fluxes to sinks, can be disproportionately affected by gamma. The direct evaluation of the contribution of gamma ray to damage in materials, quantified as a parameter of dpa, is made possible once the displacement damage cross section due to gamma rays are known. In this work, we present calculations for gamma ray displacement cross sections in various materials in the energy range

  8. Forced Displacement : Moving from Managing Risk to Facilitating Opportunity

    OpenAIRE

    Lakhani, Sadaf

    2013-01-01

    Displacement is most commonly perceived as a situation of crisis; a time in which risks to the displaced and to host communities need to be mitigated and managed. However, if managed well, displacement can also bring new opportunities for the displaced and host communities to improve their lives. This paper looks at the predominant reasons why displacement is viewed and assisted by the aid community as a humanitarian issue, rather than as a phenomenon for which development thinking and develo...

  9. Utilization of an ultrasound beam steering angle for measurements of tissue displacement vector and lateral displacement

    Directory of Open Access Journals (Sweden)

    Chikayoshi Sumi

    2010-09-01

    Full Text Available Chikayoshi SumiDepartment of Information and Communication Sciences, Faculty of Science and Technology, Sophia University, Tokyo, JapanAbstract: A number of ultrasonic displacement/velocity measurement methods have been extensively developed for measurements of blood flow, tissue motion, and strain. Lateral modulation (LM methods have also been reported using steered, crossed beams, and these methods permit measurements of displacement vectors. In this report, a new beam steering method for the transmission and reception of ultrasound is proposed, which can enable measurements of lateral displacements and of arbitrary displacement vectors with a very high degree of accuracy. Because this beam steering method uses only a steering angle, this method is referred to as ASTA. With ASTA, the number of available methods to obtain a displacement vector measurement is limited to previously developed block-matching methods, such as the multidimensional cross-spectrum phase gradient method, and the multidimensional autocorrelation method (MAM and the multidimensional Doppler method (MDM using a block-matching method (the methods using block matching are referred to as MAMb and MDMb, respectively. Being dependent on the measurement method, only a lateral displacement measurement can be made even if the methods are multidimensional, ie, previously developed MAM and MDM using a moving average and a mirror setting of the obtained steered beams, and one-dimensional (1D, such as an autocorrelation method. Considerations of beamforming schemes using LM and ASTA show that the simple ASTA beamforming method increases capabilities for real-time measurements and requires a small physical aperture when compared with LM. For lateral displacement measurements (eg, blood flow in a carotid artery, a lateral coordinate must correspond to the direction of the target’s lateral motion, and the steering angle used is as large as possible to increase the measurement accuracy

  10. Atomic secrecy

    International Nuclear Information System (INIS)

    An article, The H-Bomb Secret: How We Got It, Why We're Telling It, by Howard Morland was to be published in The Progressive magazine in February, 1979. The government, after learning of the author's and the editors' intention to publish the article and failing to persuade them to voluntarily delete about 20% of the text and all of the diagrams showing how an H-bomb works, requested a court injunction against publication. Acting under the Atomic Energy Act of 1954, US District Court Judge Robert W. Warren granted the government's request on March 26. Events dealing with the case are discussed in this publication. Section 1, Progressive Hydrogen Bomb Case, is discussed under the following: Court Order Blocking Magazine Report; Origins of the Howard Morland Article; Author's Motives, Defense of Publication; and Government Arguments Against Disclosure. Section 2, Access to Atomic Data Since 1939, contains information on need for secrecy during World War II; 1946 Atomic Energy Act and its effects; Soviet A-Bomb and the US H-Bomb; and consequences of 1954 Atomic Energy Act. Section 3, Disputed Need for Atomic Secrecy, contains papers entitled: Lack of Studies on H-Bomb Proliferation; Administration's Position on H-Bombs; and National Security Needs vs Free Press

  11. Calculations on displacement damage and its related parameters for heavy ion bombardment in reactor materials

    International Nuclear Information System (INIS)

    The depth distribution of displacement damage expressed in displacements per atom (DPA) in reactor materials such as Mo, Nb, V, Fe and Ni bombarded by energetic nitrogen, argon and self ions with incident energy below 2 MeV was calculated following the theory developed by Lindhard and co-workers for the partition of energy as an energetic ion slowing down. In this calculation, energy loss due to electron excitation was taken into account for the atomic collision cascade after the primary knock-on process. Some parameters indispensable for the calculation such as energy loss rate, damage efficiency, projected range and its straggling were tabulated as a function of incident ion energy of 20 keV to 2 MeV. The damage and parameters were also calculated for 2 MeV nickel ions bombarding Fe targets. In this case, the DPA value is of 40--75% overestimated in a calculation disregarding electronic energy loss for primary knock-on atoms. The formula proposed in this report is significant for calculations on displacement damage produced by heavy ion bombardment as a simulation of high fluence fast neutron damage. (auth.)

  12. Atomic theories

    CERN Document Server

    Loring, FH

    2014-01-01

    Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec

  13. Boron isotopic enrichment by displacement chromatography

    International Nuclear Information System (INIS)

    10B enriched boron is used in applications requiring high volumetric neutron absorption (absorption cross section- 3837 barn for thermal and 1 barn for 1 MeV fast neutron). It is used in fast breeder reactor (as control rod material), in neutron counter, in Boron Neutron Capture Therapy etc. Owing to very small separation factor, boron isotopic enrichment is a complex process requiring large number of separation stages. Heavy Water Board has ventured in industrial scale production of 10B enriched boron using Exchange Distillation Process as well as Ion Displacement Chromatography Process. Ion Displacement Chromatography process is used in Boron Enrichment Plant at HWP, Manuguru. It is based on isotopic exchange between borate ions (B(OH)4-) on anion exchange resin and boric acid passing through resin. The isotopic exchange takes place due to difference in zero point energy of 10B and 11B

  14. Charge-displacement analysis for excited states

    Energy Technology Data Exchange (ETDEWEB)

    Ronca, Enrico, E-mail: enrico@thch.unipg.it; Tarantelli, Francesco, E-mail: francesco.tarantelli@unipg.it [Istituto CNR di Scienze e Tecnologie Molecolari, via Elce di Sotto 8, I-06123 Perugia (Italy); Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, via Elce di Sotto 8, I-06123 Perugia (Italy); Pastore, Mariachiara, E-mail: chiara@thch.unipg.it; Belpassi, Leonardo; De Angelis, Filippo [Istituto CNR di Scienze e Tecnologie Molecolari, via Elce di Sotto 8, I-06123 Perugia (Italy); Angeli, Celestino; Cimiraglia, Renzo [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Ferrara, via Borsari 46, I-44100 Ferrara (Italy)

    2014-02-07

    We extend the Charge-Displacement (CD) analysis, already successfully employed to describe the nature of intermolecular interactions [L. Belpassi et al., J. Am. Chem. Soc. 132, 13046 (2010)] and various types of controversial chemical bonds [L. Belpassi et al., J. Am. Chem. Soc. 130, 1048 (2008); N. Salvi et al., Chem. Eur. J. 16, 7231 (2010)], to study the charge fluxes accompanying electron excitations, and in particular the all-important charge-transfer (CT) phenomena. We demonstrate the usefulness of the new approach through applications to exemplary excitations in a series of molecules, encompassing various typical situations from valence, to Rydberg, to CT excitations. The CD functions defined along various spatial directions provide a detailed and insightful quantitative picture of the electron displacements taking place.

  15. Precision optical displacement measurements using biphotons

    CERN Document Server

    Lyons, Kevin; Kwiat, Paul G; Jordan, Andrew N

    2016-01-01

    We propose and examine the use of biphoton pairs, such as those created in parametric down conversion or four-wave mixing, to enhance the precision and the resolution of measuring optical displacements by position-sensitive detection. We show that the precision of measuring a small optical beam displacement with this method can be significantly enhanced by the correlation between the two photons, given the same optical mode. The improvement is largest if the correlations between the photons are strong, and falls off as the biphoton correlation weakens. More surprisingly, we find that the smallest resolvable parameter of a simple split detector scales as the inverse of the number of biphotons for small biphoton number ("Heisenberg scaling"), because the Fisher information diverges as the parameter to be estimated decreases in value. One usually sees this scaling only for systems with many entangled degrees of freedom. We discuss the transition for the split-detection scheme to the standard quantum limit scalin...

  16. Atoms as Qed bound atoms

    International Nuclear Information System (INIS)

    The relevance of Quantum Electrodynamics (Qed) in contemporary atomic structure theory is reviewed. Recent experimental advances allow both the production of heavy ions of high charge as well as the measurement of atomic properties with a precision never achieved before. The description of heavy atoms with few electrons via the successive incorporation of one, two, etcetera photons in a rigorous manner and within the bound state Furry representation of Qed is technically feasible. For many-electron atoms the many-body (correlation) effects are very important and it is practically impossible to evaluate all the relevant Feynman diagrams to the required accuracy. Thus, it is necessary to develop a theoretical scheme in which the radiative and nonradiative effects are taken into account in an effective way making emphasis in electronic correlation. Preserving gauge invariance, and avoiding both continuum dissolution and variational collapse are basic problems that must be solved when using effective potential methods and finite-basis representations of them. In this context, we shall discuss advances and problems in the description of atoms as Qed bound states. (Author)

  17. The credit market consequences of job displacement

    OpenAIRE

    Benjamin J. Keys

    2010-01-01

    This paper demonstrates the important role of job displacement in the household bankruptcy decision. I develop a dynamic, forward-looking model of unemployment and bankruptcy where persistent negative income shocks increase a household's likelihood of filing for bankruptcy both immediately and in the future. Consistent with the model's predictions, I find that households in the NLSY are 2.5 times more likely to file for bankruptcy in the year immediately following a job loss, at a rate of an ...

  18. Forced displacement in Colombia: Magnitude and causes

    OpenAIRE

    Ana María Ibáñez

    2009-01-01

    The article describes the magnitude, geographical extent, and causes of forced populationdisplacements in Colombia. Forced migration in Colombia is a war strategy adopted by armed groups to strengthen territorial strongholds, weaken civilian support to the enemy, seize valuable lands, and produce and transport illegal drugs with ease. Forced displacement in Colombia today affects 3.5 million people. Equivalent to 7.8 percent of Colombia’s population, and second worldwide only to Sudan, this s...

  19. Environmentally-induced displacement and human security

    OpenAIRE

    Terminski, Bogumil

    2012-01-01

    We can distinguish two general causes of internal displacement worldwide: 1. the impact of threats to and ensuing decline in the level of human security below that needed for normal existence in the homeland territory, 2. administrative compulsion to leave the current place of residence. Every year, at least tens of millions of people on all continents are forced to leave their places of residence. The predominant cause is the occurrence of natural disasters, creating the most dynamic categor...

  20. Ultra-High-Frequency Capacitive Displacement Sensor

    Science.gov (United States)

    Vanzandt, Thomas R.; Kenny, Thomas W.; Kaiser, William J.

    1994-01-01

    Improved class of compact, high-resolution capacitive displacement sensors operates at excitation frequency of 915 MHz and measures about 7.5 by 4 by 2 centimeters. Contains commercially available 915-MHz oscillator and transmission-line resonator. Resonator contains stripline inductor in addition to variable capacitor. Ultrahigh excitation frequency offers advantages of resolution and frequency response. Not deleteriously affected by mechanical overdriving, or contact between electrodes.

  1. Two-Domain DNA Strand Displacement

    OpenAIRE

    Luca Cardelli

    2010-01-01

    We investigate the computing power of a restricted class of DNA strand displacement structures: those that are made of double strands with nicks (interruptions) in the top strand. To preserve this structural invariant, we impose restrictions on the single strands they interact with: we consider only two-domain single strands consisting of one toehold domain and one recognition domain. We study fork and join signal-processing gates based on these structures, and we show that these systems are ...

  2. Relativistic Lagrangian displacement field and tensor perturbations

    OpenAIRE

    Rampf, C.; Wiegand, A.

    2014-01-01

    We investigate the purely spatial Lagrangian coordinate transformation from the Lagrangian to the fundamental Eulerian frame. We demonstrate three techniques for extracting the relativistic displacement field from a given solution in the Lagrangian frame. These techniques are (a) from defining a local set of Eulerian coordinates embedded into the Lagrangian frame; (b) from performing a specific gauge transformation; and (c) from a fully non-perturbative approach based on the ADM split. The la...

  3. Probing gaugino coannihilation with displaced vertex searches

    CERN Document Server

    Nagata, Natsumi

    2016-01-01

    Bino-like dark matter in supersymmetric theories tends to suffer from over-production. This problem can be evaded if there is another gaugino which has a mass close to the bino mass so that it enhances the annihilation rate of bino dark matter through coannihilation. We study such possibilities in high-scale supersymmetric models, and show that searches for long-lived particles with displaced vertices can test the bino-gaugino coannihilation scenario in the forthcoming LHC experiments.

  4. Laser Measurement of Building Vibration and Displacement

    OpenAIRE

    A.J. Bougard; B.R. Ellis

    2000-01-01

    This paper considers four laser systems used by the Building Research Establishment (BRE) to investigate the behaviour of structures. Lasers enable remote measurements of vibration and displacement to be taken where access to a structure is difficult or where fire, explosion or structural collapse creates a hazardous environment. Each system will be described, and its use illustrated using measurements taken on real structures.The four systems are:1. Laser Interferometer: This is used to meas...

  5. Comparing Teaching Approaches About Maxwell's Displacement Current

    Science.gov (United States)

    Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

    2014-08-01

    Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment relationship). Despite the consensus among physics educators concerning the relevance of the topic, there are many possible ways to interpret and justify the need for the displacement current term. With the goal of understanding the didactical transposition of this topic more deeply, we investigate three of its domains: (1) The historical development of Maxwell's reasoning; (2) Different approaches to justify the term insertion in physics textbooks; and (3) Four lectures devoted to introduce the topic in undergraduate level given by four different professors. By reflecting on the differences between these three domains, significant evidence for the knowledge transformation caused by the didactization of this episode is provided. The main purpose of this comparative analysis is to assist physics educators in developing an epistemological surveillance regarding the teaching and learning of the displacement current.

  6. Vertical displacement and position control in tokamaks

    International Nuclear Information System (INIS)

    Free-boundary nearly rigid displacements are considered in a plasma confined by a magnetic field consisting of one part generated by the plasma current density, and one part being due to steady currents in fixed external conductors. An induced surface current effect and a related force on the plasma arise when the externally applied field is inhomogeneous in the direction of displacement. This additional force has not been taken into account in conventional MHD theory. In the particular case of tokamaks , the induced surface current effect has two impacts on vertical nearly rigid displacements. First, there arises an additional restoring force and a positive contribution to the change in potential energy when the externally applied field is inhomogeneous in the vertical direction. A special design of poloidal field coils can thus provide new means for vertical position control in tokamaks, also in the case of strongly elongated cross-sections. Second, an earlier simplified model, in which the plasma is represented by a line current, has to be modified since the plasma is a highly conducting body of finite size. 4 refs

  7. Numerical computation of in-plane displacements and their detection in the near field by double-exposure objective speckle photography

    Science.gov (United States)

    Gascón, Francisco; Salazar, Félix

    2008-12-01

    A model of a rough surface to the scale of the optical wavelength is proposed, with randomly distributed zero-mean Gaussian heights. It is assumed that the aforesaid surface is illuminated by a coherent light beam of homogeneous intensity. An in-plane pure translation of this surface is simulated on a PC by means of the Matlab program. In the near-field optical regions the Fraunhofer approximation and the subsequent FFT are not suitable for application in the generation of a speckle pattern. Hence, with the aim of calculating the translation of the rough surface by means of double-exposure objective speckle photography using the point-wise filtering technique (PWFT), the Fresnel-Kirchhoff integral is first employed to obtain the speckle intensity near the surface on a photographic plate, and then the intensity pattern produced by the diffraction of the plate is determined in the far field (Fraunhofer), which suffices to calculate the modulus of displacement through the Young's fringes. The results are analyzed according to surface roughness and the sample distance to the recording plane.

  8. Ultrasonography for non-displaced and mini-displaced humeral lateral condyle fractures in children

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-dong; CHEN Hua

    2008-01-01

    Objective: To evaluate the value of ultrasonography in non-displaced and mini-displaced humeral lateral condyle fractures in children.Methods: Nine children aged 2-9 years with non-displaced or mini-displaced humeral lateral condyle fractures were examined by high-resolution ultrasonography.The fracture line through the joint surface was visualized by ultrasonography in 6 case,in which closed reduction and percutaneous pinning was performed on 3 patients and other 3 patients did not receive the treatment because of patients' or their parents'refusal.In the remaining 3 children,ultrasonography did not reveal the cartilaginous trochle involvement at the joint surface and conservative treatment was adopted.Results: The average follow-up period was 8 months.The sonographic findings were confirmed by magnetic resonance imaging in one child who received conservative treatment and another child who received percutaneous pinning.The elbow function and fractttre healing were good in cases received closed reduction and percutaneous pinning.Among the three cases who refused to receive closed reduction and internal f'txation,re-displacement occurred in 1 case and delayed union in 1 case.All three cases receiving conservative treatment had good results both in elbow function and fracture healing.Conclusion: High-resolution ultrasonography enable to reveal non-displaced and mini-displaced humeral lateral condyle fractures as well as to ascertain whether the cartilaginous trochlea humeri was involved.For these cases,arthrography or magnetic resonance imaging is unnecessary.

  9. Displacement Mechanism of Polymer Flooding by Molecular Tribology

    Institute of Scientific and Technical Information of China (English)

    YANG Er-Long; SONG Kao-Ping

    2006-01-01

    @@ Whether polymer flooding can enhance displacement efficiency or not is still a problem under debate. Laboratory experiment, numerical simulation and core data analysis are the commonly used means to study polymer flooding displacement efficiency.

  10. Defects and threshold displacement energies in SrTiO{sub 3} perovskite using atomistic computer simulations

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, B.S. [Australian Nuclear Science and Technology Organisation, Private Mail Bag 1, New Illawarra Road, Menai NSW 2234 (Australia); School of Physics, University of Sydney NSW 2006 (Australia); E-mail: b.thomas@ansto.gov.au; Marks, N.A. [School of Physics, University of Sydney NSW 2006 (Australia); Begg, B.D. [Australian Nuclear Science and Technology Organisation, Private Mail Bag 1, New Illawarra Road, Menai NSW 2234 (Australia)

    2007-01-15

    The mode and energy of simple defect incorporation in SrTiO{sub 3} (vacancies and interstitials) is quantified using computer simulation techniques with an empirical partial charge model of interatomic forces, as well as using density functional theory calculations. Oxygen and strontium interstitials form split-interstitial configurations whereas titanium interstitials occupy channel positions. Defect migration energies and paths are also considered; interstitials are more mobile than vacancies, with a low predicted oxygen interstitial migration energy of around 0.3 eV. We also calculate the threshold displacement energy (E{sub d}) for each atom type in SrTiO{sub 3} perovskite using molecular dynamics simulations, by introducing a primary knock-on atom with a range of energies (20-250 eV) in principal crystallographic directions at 300 K. We find that all atom types are most easily displaced via direct replacement sequences on their own sublattices, which are extensive for Sr atoms due to focusson processes acting along channels. The weighted average threshold displacement energies (for use in TRIM-type calculations) are 50 eV for oxygen, 70 eV for strontium and 140 eV for titanium atoms. These computed energies for O and Sr are comparable to experimentally-derived values in perovskites, whereas the E{sub d} for Ti is much higher; it is expected that the value reported here is more accurate due to experimental difficulties in distinguishing different types of defects.

  11. The Theme of Displacement in Contemporary Art

    Directory of Open Access Journals (Sweden)

    John POTTS

    2012-03-01

    Full Text Available Cet article examine les images et idées de dislocation dans des œuvres d'art récentes. Le thème du déplacement ou de la dislocation est traité dans le contexte de l'aspect globalisant de l'art contemporain, considéré lui-même comme un reflet de la mondialisation. Les principaux textes théoriques qui influencent et informent les pratiques en matière de conservation sont abordés, entre autres les écrits de Giorgio Agamben, Nicolas Bourriaud et Rex Butler. Le thème de la dislocation dans l'art contemporain est analysé au travers des œuvres de nombreux artistes, tels que Francis Alÿs, Bill Fontana, Allan Sekula, Chen Chieh-jen, Ai Wei Wei, Rosemary Laing, Mike Parr, Santiago Sierra, Rebecca Belmore et Tracey Moffatt.This essay considers images and ideas of displacement in recent works of art. The theme of displacement is examined in the context of the globalist aspect of contemporary art, itself a reflection of globalisation. Influential theoretical texts informing curatorial practice and the discourse of contemporary art theory are discussed, including the writings of Girogio Agamben, Nicolas Bourriaud and Rex Butler. The theme of displacement in contemporary art is analysed with regard to the work of many artists, including Francis Alÿs, Bill Fontana, Allan Sekula, Chen Chieh-jen, Ai Wei Wei, Rosemary Laing, Mike Parr, Santiago Sierra, Rebecca Belmore and Tracey Moffatt.

  12. Year of displaced people’s rights in Colombia

    OpenAIRE

    Marco Alberto Romero

    2007-01-01

    A Campaign for the Rights of Displaced People in Colombia, launched in 2007 by UNHCR, Colombian NGO CODHES and the Catholic Church, has tried to raise awareness in Colombia and the international community about the severity of the country’s displacement crisis and its failure to guarantee the rights of displaced people.

  13. 40 CFR 86.419-2006 - Engine displacement, motorcycle classes.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Engine displacement, motorcycle... Emission Regulations for 1978 and Later New Motorcycles, General Provisions § 86.419-2006 Engine displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine...

  14. 40 CFR 86.419-78 - Engine displacement, motorcycle classes.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Engine displacement, motorcycle... Emission Regulations for 1978 and Later New Motorcycles, General Provisions § 86.419-78 Engine displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded...

  15. Displacer rod for use in a mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    A displacer rod for use in a mechanical spectral shift pressurized water nuclear reactor comprises a sectioned substantially hollow low neutron absorbing metal rod capable of displacing reactor coolant without absorbing a high amount of neutrons. The tubular sections preferably consist of stainless steel and Zircaloy tubing interconnected by a solid Zircaloy metal rod and may contain pellets for weighting the displacer rod. (author)

  16. Two-Domain DNA Strand Displacement

    Directory of Open Access Journals (Sweden)

    Luca Cardelli

    2010-06-01

    Full Text Available We investigate the computing power of a restricted class of DNA strand displacement structures: those that are made of double strands with nicks (interruptions in the top strand. To preserve this structural invariant, we impose restrictions on the single strands they interact with: we consider only two-domain single strands consisting of one toehold domain and one recognition domain. We study fork and join signal-processing gates based on these structures, and we show that these systems are amenable to formalization and to mechanical verification.

  17. Two-Domain DNA Strand Displacement

    CERN Document Server

    Cardelli, Luca

    2010-01-01

    We investigate the computing power of a restricted class of DNA strand displacement structures: those that are made of double strands with nicks (interruptions) in the top strand. To preserve this structural invariant, we impose restrictions on the single strands they interact with: we consider only two-domain single strands consisting of one toehold domain and one recognition domain. We study fork and join signal-processing gates based on these structures, and we show that these systems are amenable to formalization and to mechanical verification.

  18. Simulating People Moving in Displacement Ventilated Rooms

    DEFF Research Database (Denmark)

    Mattsson, M.; Bjørn, Erik; Sandberg, M.; Nielsen, Peter V.

    A displacement ventilation system works better the more uni-directional the air flow through the ventilated room is: from floor to ceiling. Thus, from an air quality point of view, there should be as little vertical mixing of the room air as possible. It is therefore comprehensible that physical...... activity in the room -like peoples movements -in previous studies has been shown to influence the effectiveness of the ventilation. In this study we have compared results from previous tests, where a cylindrical person simulator was used, to results obtained when using a person simulator of more human...

  19. Mirror displacement energies and neutron skins

    CERN Document Server

    Duflo, J

    2002-01-01

    Assuming isospin conservation, it is shown that a single expression accounts for both neutron and proton radii. Excellent fits to the former turn out to be consistent with different neutron skins. To fix their values the displacement energies between mirror nuclei, MDE, are calculated using an accurately derived Coulomb energy, and smooth averages of the charge symmetry breaking potentials constrained to state of the art values. Optimum agreement with observed MDE and neutron skins is obtained. The remaining uncertainties are shown to be due to shell effects.

  20. Dynamics and structure of energetic displacement cascades

    International Nuclear Information System (INIS)

    This paper summarizes recent progress in the understanding of energetic displacement cascades and the primary state of damage in metals. On the theoretical side, the availability of supercomputers has greatly enhanced our ability to simulate cascades by molecular dynamics. Recent application of this simulation technique to Cu and Ni provides new insight into the dynamics of cascade processes. On the experimental side, new data on ion beam mixing and in situ electron microscopy studies of ion damage at low temperatures reveal the role of the thermodynamic properties of the material on cascade dynamics and structure. 38 refs., 9 figs

  1. Fluorescence enhancement aided by metal ion displacement.

    Science.gov (United States)

    Susini, Vanessa; Ienco, Andrea; Lucia Rossi, Veronica; Paolicchi, Aldo; Sanesi, Antonio

    2016-06-15

    Immunosensors are one of the most common platform used in clinical laboratories, in particular the class based on Enzyme Linked Fluorescent Assays (ELFA) takes advantage of the amplification step of the enzyme, usually the alkaline phosphatase, that catalyzes the hydrolysis of a fluorescent substrate leading it to fluoresce. Anyway, they suffer in sensitivity if compared to molecular diagnostic or more modern in vitro diagnostic devices. In our work, a simple and effective mechanism to enhance the fluorescent signal, and hence the sensitivity of the system, is presented. It is based on the metal ion displacement principle in which a second fluorophore, in our case Calcein Blue, quenched by a cobalt ion is add to the first one (4-MUP), and, in presence of inorganic phosphate, it will be progressively activated by the inorganic phosphate itself leading to the metal displacement. In this way Calcein Blue, newly free to fluoresce, contributes to global fluorescent signal generated by 4-MU. We have tested our proof of principle on a currently used immunoanalyzer, that is VIDAS® system (bioMérieux, Marcy l'Etoile, France) obtaining a fluorescence enhancement of about 50% for each concentration of hydrolyzed 4-MUP tested. PMID:26851581

  2. Precision optical displacement measurements using biphotons

    Science.gov (United States)

    Lyons, Kevin; Pang, Shengshi; Kwiat, Paul G.; Jordan, Andrew N.

    2016-04-01

    We propose and examine the use of biphoton pairs, such as those created in parametric down-conversion or four-wave mixing, to enhance the precision and the resolution of measuring optical displacements by position-sensitive detection. We show that the precision of measuring a small optical beam displacement with this method can be significantly enhanced by the correlation between the two photons, given the same optical mode. The improvement is largest if the correlations between the photons are strong, and falls off as the biphoton correlation weakens. More surprisingly, we find that the smallest resolvable parameter of a simple split detector scales as the inverse of the number of biphotons for small biphoton number ("Heisenberg scaling"), because the Fisher information diverges as the parameter to be estimated decreases in value. One usually sees this scaling only for systems with many entangled degrees of freedom. We discuss the transition for the split-detection scheme to the standard quantum limit scaling for imperfect correlations as the biphoton number is increased. An analysis of an N -pixel detector is also given to investigate the benefit of using a higher resolution detector. The physical limit of these metrology schemes is determined by the uncertainty in the birth zone of the biphoton in the nonlinear crystal.

  3. Exotic atoms

    International Nuclear Information System (INIS)

    The experiments use a solid hydrogen layer to form muonic hydrogen isotopes that escape into vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target has been constructed which exploits muonic atom emission in order to learn more about the energy dependence of transfer and muon molecular formation

  4. Atomic Clocks

    Science.gov (United States)

    Wynands, Robert

    Time is a strange thing. On the one hand it is arguably the most inaccessible physical phenomenon of all: both in that it is impossible to manipulate or modify—for all we know—and in that even after thousands of years mankind's philosophers still have not found a fully satisfying way to understand it. On the other hand, no other quantity can be measured with greater precision. Today's atomic clocks allow us to reproduce the length of the second as the SI unit of time with an uncertainty of a few parts in 1016—orders of magnitude better than any other quantity. In a sense, one can say [1

  5. Single atom measurement and atomic manipulation using atomic force microscope

    International Nuclear Information System (INIS)

    This paper explains studies to measure atomic force as the force linking an atom and atom, using an atomic force microscope (AFM). First, it describes the principle and device configuration of AFM, and as an example of the atomic force measurement of Si atoms on the surface of Si(111)-(7x7), it describes the technique to measure atomic force using AFM, as well as the uncertainty of probe tip against atomic force. In addition, it describes the following items on the measurement results of chemical bonding force: (1) chemical bonding force vs physical force and chemical bonding force vs current on the surface of Si(111)-(7x7), (2) chemical bonding force and element dependence on the surface of Si/Sn(111)-(√3x√3), (3) atomic manipulation based on AMF, and (4) relationship between atomic manipulation and the size of chemical bonding force with a probe. (A.O.)

  6. Long-Time Mean Square Displacements in Proteins

    CERN Document Server

    Vural, Derya; Smith, Jeremy C; Glyde, Henry R

    2013-01-01

    We propose a method for obtaining the intrinsic, long time mean square displacement (MSD) of atoms and molecules in proteins from finite time molecular dynamics (MD) simulations. Typical data from simulations are limited to times of 1 to 10 ns and over this time period the calculated MSD continues to increase without a clear limiting value. The proposed method consists of fitting a model to MD simulation-derived values of the incoherent intermediate neutron scattering function, $I_{inc}(Q,t)$, for finite times. The infinite time MSD, $$, appears as a parameter in the model and is determined by fits of the model to the finite time $I_{inc}(Q,t)$. Specifically, the $$ is defined in the usual way in terms of the Debye-Waller factor as $I(Q,t = \\infty) = \\exp(- Q^2 /3)$. The method is illustrated by obtaining the intrinsic MSD $$ of hydrated lysozyme powder (h = 0.4 g water/g protein) over a wide temperature range. The intrinsic $$ obtained from data out to 1 ns and to 10 ns is found to be the same. The intrinsi...

  7. Pulse tube stirling machine with warm gas-driven displacer

    Science.gov (United States)

    Zhu, Shaowei; Nogawa, Masafumi

    2010-05-01

    A pulse tube type stirling machine with warm gas-driven displacer which has a displacer rod is discussed with numerical simulation when it is used as a cryogenic refrigerator, room temperature refrigerator and engine. It has both the advantages of gas-driven-stirling machine with high efficiency and simplicity and the advantages of pulse tube machine with no moving parts at low temperatures. A nodal analysis method that includes the linear motor and the displacer in the machine is introduced. Numerical results show that it has high potential to be used as the cryogenic refrigerator, room temperature refrigerator and engine. In this type of machine, there is an optimum phase angle between displacer and piston, and an optimum swept volume ratio of displacer over compressor for efficiency. The phase angle and swept volume ratio can be adjusted by the natural frequency of the displacer and the diameter of the displacer rod when it is used as a refrigerator.

  8. The effect of base pair mismatch on DNA strand displacement

    CERN Document Server

    Broadwater, Bo

    2016-01-01

    DNA strand displacement is a key reaction in DNA homologous recombination and DNA mismatch repair and is also heavily utilized in DNA-based computation and locomotion. Despite its ubiquity in science and engineering, sequence-dependent effects of displacement kinetics have not been extensively characterized. Here, we measured toehold-mediated strand displacement kinetics using single-molecule fluorescence in the presence of a single base pair mismatch. The apparent displacement rate varied significantly when the mismatch was introduced in the invading DNA strand. The rate generally decreased as the mismatch in the invader was encountered earlier in displacement. Our data indicate that a single base pair mismatch in the invader stalls branch migration, and displacement occurs via direct dissociation of the destabilized incumbent strand from the substrate strand. We combined both branch migration and direct dissociation into a model, which we term, the concurrent displacement model, and used the first passage t...

  9. Magnetic measurements with atomic-plane resolution.

    Science.gov (United States)

    Rusz, Ján; Muto, Shunsuke; Spiegelberg, Jakob; Adam, Roman; Tatsumi, Kazuyoshi; Bürgler, Daniel E; Oppeneer, Peter M; Schneider, Claus M

    2016-01-01

    Rapid development of magnetic nanotechnologies calls for experimental techniques capable of providing magnetic information with subnanometre spatial resolution. Available probes of magnetism either detect only surface properties, such as spin-polarized scanning tunnelling microscopy, magnetic force microscopy or spin-polarized low-energy electron microscopy, or they are bulk probes with limited spatial resolution or quantitativeness, such as X-ray magnetic circular dichroism or classical electron magnetic circular dichroism (EMCD). Atomic resolution EMCD methods have been proposed, although not yet experimentally realized. Here, we demonstrate an EMCD technique with an atomic size electron probe utilizing a probe-corrected scanning transmission electron microscope in its standard operation mode. The crucial element of the method is a ramp in the phase of the electron beam wavefunction, introduced by a controlled beam displacement. We detect EMCD signals with atomic-plane resolution, thereby bringing near-atomic resolution magnetic circular dichroism spectroscopy to hundreds of laboratories worldwide. PMID:27578421

  10. Diffracted field distribution from a knife-edge truncated semi- Gaussian beam as an atomic (molecular) mirror

    Institute of Scientific and Technical Information of China (English)

    Zheng Ping; Gao Wei-Jian; Yin Jian-Ping

    2006-01-01

    We investigate the diffraction characteristics of an incident Gaussian beam cut by a straight edge bounding a semi-infinite opaque plane using Kirchhoff scalar wave theory in the Fresnel limit, and propose a new and simple mirror scheme to reflect atoms by using the intensity gradient induced by a blue-detuned semi-Gaussian laser beam. The optical potential of the diffracted light of the knife-cut semi-Gaussian beam for 85Rb atom and its spontaneous emission probability are calculated and compared with the performance of the evanescent-wave mirror. Our study shows that the optical potential of the diffracted light of the semi-Gaussian beam is far higher than that of the evanescent light wave, and the maximum normal velocity of the incident atoms can be far greater than that of the evanescent light wave under the same parameters, so the blue-detuned semi-Gaussian beam, as a novel atomic mirror, can be used to efficiently reflect cold atoms with a normal velocity of greater than 1 m/s. However, the intensity gradient (force) of the diffracted light of the semi-Gaussian-beam is much smaller than that of the evanescent light wave, so its spontaneous emission probability is greater than that from the evanescent-wave when the normal velocity of incident atoms is greater.

  11. Observation of Lasing Mediated by Collective Atomic Recoil

    CERN Document Server

    Kruse, D; Zimmermann, C; Courteille, P W; Courteille, Ph.W.

    2003-01-01

    We observe the buildup of a frequency-shifted reverse light field in a unidirectionally pumped high-Q optical ring cavity serving as a dipole trap for cold atoms. This effect is enhanced and a steady state is reached, if via an optical molasses an additional friction force is applied to the atoms. We observe the displacement of the atoms accelerated by momentum transfer in the backscattering process and interpret our observations in terms of the collective atomic recoil laser. Numerical simulations are in good agreement with the experimental results.

  12. Atom Skimmers and Atom Lasers Utilizing Them

    Science.gov (United States)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  13. Analog Computation by DNA Strand Displacement Circuits.

    Science.gov (United States)

    Song, Tianqi; Garg, Sudhanshu; Mokhtar, Reem; Bui, Hieu; Reif, John

    2016-08-19

    DNA circuits have been widely used to develop biological computing devices because of their high programmability and versatility. Here, we propose an architecture for the systematic construction of DNA circuits for analog computation based on DNA strand displacement. The elementary gates in our architecture include addition, subtraction, and multiplication gates. The input and output of these gates are analog, which means that they are directly represented by the concentrations of the input and output DNA strands, respectively, without requiring a threshold for converting to Boolean signals. We provide detailed domain designs and kinetic simulations of the gates to demonstrate their expected performance. On the basis of these gates, we describe how DNA circuits to compute polynomial functions of inputs can be built. Using Taylor Series and Newton Iteration methods, functions beyond the scope of polynomials can also be computed by DNA circuits built upon our architecture. PMID:27363950

  14. Axial flow positive displacement worm compressor

    Science.gov (United States)

    Murrow, Kurt David (Inventor); Giffin, Rollin George (Inventor); Fakunle, Oladapo (Inventor)

    2010-01-01

    An axial flow positive displacement compressor has an inlet axially spaced apart and upstream from an outlet. Inner and outer bodies have offset inner and outer axes extend from the inlet to the outlet through first and second sections of a compressor assembly in serial downstream flow relationship. At least one of the bodies is rotatable about its axis. The inner and outer bodies have intermeshed inner and outer helical blades wound about the inner and outer axes respectively. The inner and outer helical blades extend radially outwardly and inwardly respectively. The helical blades have first and second twist slopes in the first and second sections respectively. The first twist slopes are less than the second twist slopes. An engine including the compressor has in downstream serial flow relationship from the compressor a combustor and a high pressure turbine drivingly connected to the compressor by a high pressure shaft.

  15. Personal Exposure in Displacement Ventilated Rooms

    DEFF Research Database (Denmark)

    Brohus, Henrik; Nielsen, Peter Vilhelm

    1996-01-01

    Personal exposure in a displacement ventilated room is examined. The stratified flow and the considerable concentration gradients necessitate an improvement of the widely used fully mixing compartmental approach. The exposure of a seated and a standing person in proportion to the stratification...... height is examined by means of full-scale measurements. A breathing thermal manikin is used to simulate a person. It is found that the flow in the boundary layer around a person is able to a great extent to entrain and transport air from below the breathing zone. In the case of non-passive, heated...... contaminant sources, this entrainment improves the indoor air quality. Measurements of exposure due to a passive contaminant source show a significant dependence on the flow field as well as on the contaminant source location. Poor system performance is found in the case of a passive contaminant released in...

  16. Displaced fracture through the anterior atlantal synchondrosis

    Energy Technology Data Exchange (ETDEWEB)

    Thakar, Chrishan; Allibone, James [Royal National Orthopaedic Hospital NHS Trust, Department of Spinal Deformity, Stanmore, Middlesex (United Kingdom); Harish, Srinivasan [Royal National Orthopaedic Hospital NHS Trust, Department of Radiology, Stanmore, Middlesex (United Kingdom); Saifuddin, Asif [Royal National Orthopaedic Hospital NHS Trust, Department of Radiology, Stanmore, Middlesex (United Kingdom); University College, The Institute of Orthopaedics and Musculoskeletal Sciences, London (United Kingdom)

    2005-09-01

    In the acute setting, accurate radiological interpretation of paediatric cervical spine trauma can be difficult due to a combination of normal variants and presence of multiple synchondroses. We present a rare case of a fracture through the anterior atlantal synchondrosis in a paediatric spine. A five-year-old boy, who fell backwards onto the top of his head while swinging across on a monkey bar frame, presented with neck pain, cervical muscle spasm and decreased right lateral rotation and extension of his neck. Computed tomography showed a displaced diastatic fracture through right anterior atlantal synchondrosis. There are only 12 cases of paediatric C1 fractures reported in the world literature. The importance of considering this diagnosis in the appropriate clinical setting, and the normal variants in the paediatric atlas that can cause diagnostic dilemma to the interpreting radiologist, are discussed in this case report. (orig.)

  17. Micromachined Tunneling Displacement Transducers for Physical Sensors

    Science.gov (United States)

    Kenny, T. W.; Kaiser, W. J.; Podosek, J. A.; Rockstad, H. K.; Reynolds, J. K.; Vote, E. C.

    1993-01-01

    We have designed and constructed a series of tunneling sensors which take advantage of the extreme position sensitivity of electron tunneling. In these sensors, a tunneling displacement transducer, based on scanning tunneling microscopy principles, is used to detect the signal-induced motion of a sensor element. Through the use of high-resonant frequency mechanical elements for the transducer, sensors may be constructed which offer wide bandwidth, and are robust and easily operated. Silicon micromachining may be used to fabricate the transducer elements, allowing integration of sensor and control electronics. Examples of tunneling accelerometers and infrared detectors will be discussed. In each case, the use of the tunneling transducer allows miniaturization of the sensor as well as enhancement of the sensor performance.

  18. Relativistic Lagrangian displacement field and tensor perturbations

    CERN Document Server

    Rampf, Cornelius

    2014-01-01

    We investigate the purely spatial Lagrangian coordinate transformation from the Lagrangian to the fundamental Eulerian frame. We demonstrate three techniques for extracting the relativistic displacement field from a given solution in the Lagrangian frame. These techniques are (a) from defining a local set of Eulerian coordinates embedded into the Lagrangian frame; (b) from performing a specific gauge transformation; and (c) from a fully non-perturbative approach based on the ADM split. The latter approach shows that this decomposition is not tied to a specific perturbative formulation for the solution of the Einstein equations. Rather, it can be defined at the level of the non-perturbative coordinate change from the Lagrangian to the Eulerian description. Studying such different techniques is useful because it allows us to compare and develop further the various approximation techniques available in the Lagrangian formulation. We find that one has to solve for gravitational waves in the relativistic analysis,...

  19. Superconducting inductive displacement detection of a microcantilever

    Energy Technology Data Exchange (ETDEWEB)

    Vinante, A., E-mail: anvinante@fbk.eu [Istituto di Fotonica e Nanotecnologie, CNR - Fondazione Bruno Kessler, I-38123 Povo, Trento (Italy)

    2014-07-21

    We demonstrate a superconducting inductive technique to measure the displacement of a micromechanical resonator. In our scheme, a type I superconducting microsphere is attached to the free end of a microcantilever and approached to the loop of a dc Superconducting Quantum Interference Device (SQUID) microsusceptometer. A local magnetic field as low as 100 μT, generated by a field coil concentric to the SQUID, enables detection of the cantilever thermomechanical noise at 4.2 K. The magnetomechanical coupling and the magnetic spring are in good agreement with image method calculations assuming pure Meissner effect. These measurements are relevant to recent proposals of quantum magnetomechanics experiments based on levitating superconducting microparticles.

  20. Searching for displaced Higgs boson decays

    Science.gov (United States)

    Csáki, Csaba; Kuflik, Eric; Lombardo, Salvator; Slone, Oren

    2015-10-01

    We study a simplified model of the Standard Model (SM) Higgs boson decaying to a degenerate pair of scalars which travel a macroscopic distance before decaying to SM particles. This is the leading signal for many well-motivated solutions to the hierarchy problem that do not propose additional light colored particles. Bounds for displaced Higgs boson decays below 10 cm are found by recasting existing tracker searches from Run I. New tracker search strategies, sensitive to the characteristics of these models and similar decays, are proposed with sensitivities projected for Run II at √{s }=13 TeV . With 20 fb-1 of data, we find that Higgs branching ratios down to 2 ×1 0-4 can be probed for centimeter decay lengths.

  1. Intrinsic mean-square displacements in proteins

    Science.gov (United States)

    Vural, Derya; Glyde, Henry R.

    2012-07-01

    The thermal mean-square displacement (MSD) of hydrogen in proteins and its associated hydration water is measured by neutron scattering experiments and used an indicator of protein function. The observed MSD as currently determined depends on the energy resolution width of the neutron scattering instrument employed. We propose a method for obtaining the intrinsic MSD of H in the proteins, one that is independent of the instrument resolution width. The intrinsic MSD is defined as the infinite time value of that appears in the Debye-Waller factor. The method consists of fitting a model to the resolution broadened elastic incoherent structure factor or to the resolution dependent MSD. The model contains the intrinsic MSD, the instrument resolution width, and a rate constant characterizing the motions of H in the protein. The method is illustrated by obtaining the intrinsic MSD of heparan sulphate (HS-0.4), ribonuclease A, and staphysloccal nuclase (SNase) from data in the literature.

  2. Intrinsic Mean Square Displacements in Proteins

    CERN Document Server

    Vural, Derya

    2012-01-01

    The thermal mean square displacement (MSD) of hydrogen in proteins and its associated hydration water is measured by neutron scattering experiments and used an indicator of protein function. The observed MSD as currently determined depends on the energy resolution width of the neutron scattering instrument employed. We propose a method for obtaining the intrinsic MSD of H in the proteins, one that is independent of the instrument resolution width. The intrinsic MSD is defined as the infinite time value of that appears in the Debye-Waller factor. The method consists of fitting a model to the resolution broadened elastic incoherent structure factor or to the resolution dependent MSD. The model contains the intrinsic MSD, the instrument resolution width and a rate constant characterizing the motions of H in the protein. The method is illustrated by obtaining the intrinsic MSD of heparan sulphate (HS-0.4), Ribonuclease A and Staphysloccal Nuclase (SNase) from data in the literature.

  3. Artificial Neural Network for Displacement Vectors Determination

    Directory of Open Access Journals (Sweden)

    P. Bohmann

    1997-09-01

    Full Text Available An artificial neural network (NN for displacement vectors (DV determination is presented in this paper. DV are computed in areas which are essential for image analysis and computer vision, in areas where are edges, lines, corners etc. These special features are found by edges operators with the following filtration. The filtration is performed by a threshold function. The next step is DV computation by 2D Hamming artificial neural network. A method of DV computation is based on the full search block matching algorithms. The pre-processing (edges finding is the reason why the correlation function is very simple, the process of DV determination needs less computation and the structure of the NN is simpler.

  4. Relativistic Lagrangian displacement field and tensor perturbations

    Science.gov (United States)

    Rampf, Cornelius; Wiegand, Alexander

    2014-12-01

    We investigate the purely spatial Lagrangian coordinate transformation from the Lagrangian to the basic Eulerian frame. We demonstrate three techniques for extracting the relativistic displacement field from a given solution in the Lagrangian frame. These techniques are (a) from defining a local set of Eulerian coordinates embedded into the Lagrangian frame; (b) from performing a specific gauge transformation; and (c) from a fully nonperturbative approach based on the Arnowitt-Deser-Misner (ADM) split. The latter approach shows that this decomposition is not tied to a specific perturbative formulation for the solution of the Einstein equations. Rather, it can be defined at the level of the nonperturbative coordinate change from the Lagrangian to the Eulerian description. Studying such different techniques is useful because it allows us to compare and develop further the various approximation techniques available in the Lagrangian formulation. We find that one has to solve the gravitational wave equation in the relativistic analysis, otherwise the corresponding Newtonian limit will necessarily contain spurious nonpropagating tensor artifacts at second order in the Eulerian frame. We also derive the magnetic part of the Weyl tensor in the Lagrangian frame, and find that it is not only excited by gravitational waves but also by tensor perturbations which are induced through the nonlinear frame dragging. We apply our findings to calculate for the first time the relativistic displacement field, up to second order, for a Λ CDM Universe in the presence of a local primordial non-Gaussian component. Finally, we also comment on recent claims about whether mass conservation in the Lagrangian frame is violated.

  5. Systematic review of mini-implant displacement under orthodontic loading

    Institute of Scientific and Technical Information of China (English)

    Manuel Nienkemper; Jörg Handschel; Dieter Drescher

    2014-01-01

    A growing number of studies have reported that mini-implants do not remain in exactly the same position during treatment, although they remain stable. The aim of this review was to collect data regarding primary displacement immediately straight after loading and secondary displacement over time. A systematic review was performed to investigate primary and secondary displacement. The amount and type of displacement were recorded. A total of 27 studies were included. Sixteen in vitro studies or studies using finite element analysis addressed primary displacement, and nine clinical studies and two animal studies addressed secondary displacement. Significant primary displacement was detected (6.4-24.4 mm) for relevant orthodontic forces (0.5-2.5 N). The mean secondary displacement ranged from 0 to 2.7 mm for entire mini-implants. The maximum values for each clinical study ranged from 1.0 to 4.1 mm for the head, 1.0 to 1.5 for the body and 1.0 to 1.92 mm for the tail part. The most frequent type of movement was controlled tipping or bodily movement. Primary displacement did not reach a clinically significant level. However, clinicians can expect relevant secondary displacement in the direction of force. Consequently, decentralized insertion within the inter-radicular space, away from force direction, might be favourable. More evidence is needed to provide quantitative recommendations.

  6. On Virtual Displacement and Virtual Work in Lagrangian Dynamics

    CERN Document Server

    Ray, S; Ray, Subhankar

    2006-01-01

    The confusion and ambiguity encountered by students, in understanding virtual displacement and virtual work, is discussed in this article. A definition of virtual displacement is presented that allows one to express them explicitly for holonomic (velocity independent), non-holonomic (velocity dependent), scleronomous (time independent) and rheonomous (time dependent) constraints. It is observed that for holonomic, scleronomous constraints, the virtual displacements are the displacements allowed by the constraints. However, this is not so for a general class of constraints. For simple physical systems, it is shown that, the work done by the constraint forces on virtual displacements is zero. This motivates Lagrange's extension of d'Alembert's principle to system of particles in constrained motion. However a similar zero work principle does not hold for the allowed displacements. It is also demonstrated that d'Alembert's principle of zero virtual work is necessary for the solvability of a constrained mechanical...

  7. Foil-strain-gauge-based displacement transducers and calibration device for displacement transducers

    International Nuclear Information System (INIS)

    Materials testing performed on various specimen materials with different techniques often reveal measuring method problems which cannot be solved by using commercial devices which are either too expensive or else are non-existent altogether. The institute remedied this situation by developing a number of laboratory devices of their own make two of which, i.e. a special displacement transducer and a device for the calibration and characteristics determination of transducers, are demonstrated in this report. (orig./HP)

  8. Displacement desorption test of coalbed methane and its mechanism exploring

    Institute of Scientific and Technical Information of China (English)

    ZHANG Suian; HUO Yongzhong; YE Jianping; TANG Shuheng; MA Dongmin

    2005-01-01

    Through the test of CH4 displaced by CO2 using the coal sample as the adsorbent, this paper has found the coalbed methane (CBM) displacement desorption phenomenon under the natural conditions and CBM mining conditions. With the help of the adsorption theory of the modern physical chemistry and interfacial chemistry, the CBM competitive adsorption and displacement desorption mechanism are intensively discussed, and a new path for studying the CBM desorption mechanism in the CBM exploitation process is explored.

  9. Collective Displacement of Modular Robots Using Self-Reconfiguration

    OpenAIRE

    Elian, Carrillo; Duhaut, Dominique

    2007-01-01

    Bioinspiration and Robotics Walking and Climbing Robots, Book edited by: Maki K. Habib , ISBN: 978-3-902613-15-8, Publisher: I-Tech Education and Publishing, Austria, Collective displacement is a very useful behaviour for living creatures. This behaviour can appear in a flock of birds, a school of fish, or a swarm of insects. Flocking behaviour is a common demonstration of the power of simple rules in collective displacement emergence by (Reynolds, 2007). The study of the displacement of a...

  10. A homogeneous nucleic acid hybridization assay based on strand displacement.

    OpenAIRE

    Vary, C P

    1987-01-01

    A homogeneous nucleic acid hybridization assay which is conducted in solution and requires no separation steps is described. The assay is based on the concept of strand displacement. In the strand displacement assay, an RNA "signal strand" is hybridized within a larger DNA strand termed the "probe strand", which is, in turn, complementary to the target nucleic acid of interest. Hybridization of the target nucleic acid with the probe strand ultimately results in displacement of the RNA signal ...

  11. Control of DNA Strand Displacement Kinetics Using Toehold Exchange

    OpenAIRE

    Zhang, David Yu; Winfree, Erik

    2009-01-01

    DNA is increasingly being used as the engineering material of choice for the construction of nanoscale circuits, structures, and motors. Many of these enzyme-free constructions function by DNA strand displacement reactions. The kinetics of strand displacement can be modulated by toeholds, short single-stranded segments of DNA that colocalize reactant DNA molecules. Recently, the toehold exchange process was introduced as a method for designing fast and reversible strand displacement reactions...

  12. Cleaning and Dewatering Fine Coal using Hydrophobic Displacement

    OpenAIRE

    Smith, Kara E.

    2008-01-01

    A new processing technique, known as hydrophobic displacement, was explored as a means of simultaneously removing both mineral matter and surface moisture from coal in a single process. Previous thermodynamic analysis suggests that coal moisture will be spontaneously displaced by any oil with a contact angle greater than ninety degrees in water. Based on these results, six methods of hydrophobic displacement were evaluated: hand shaking, screening, air classification, centrifugation, filtra...

  13. A Wireless Laser Displacement Sensor Node for Structural Health Monitoring

    OpenAIRE

    Se Woon Choi; Yousok Kim; Jong Moon Kim; Hyo Seon Park

    2013-01-01

    This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM). The proposed measurement system consists of a laser displacement sensor (LDS) and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA) communication module, a processor, and a power module. An LDS with a long measurement distanc...

  14. Time-dependent Displaced and Squeezed Number States

    CERN Document Server

    Kim, S P

    2004-01-01

    We generalize the wave functions of the displaced and squeezed number states, found by Nieto, to a time-dependent harmonic oscillator with variable mass and frequency. These time-dependent displaced and squeezed number states are obtained by first squeezing and then displacing the exact number states and are exact solutions of the Schr\\"{o}dinger equation. Further, these wave functions are the time-dependent squeezed harmonic-oscillator wave functions centered at classical trajectories.

  15. In-plane displacement measurement in vortex metrology

    OpenAIRE

    Angel-Toro, Luciano; Sierra-Sosa, Daniel; Tebaldi, Myrian; Bolognini, N??stor

    2013-01-01

    Recently we proposed an alternative method of displacement analysis in vortex metrology, based on the application of the Fourier optics techniques, that is suitable for an intermediate range of displacement measurements ranging below the resolution of speckle photography and above that of the conventional vortex metrology. However, for smaller displacements, we introduce an approach to perform the Fourier analysis from vortex networks. In this work, we present an enhanced method for measuring...

  16. Microstructural changes of T-91 alloy irradiated by Fe self ions to ultrahigh displacement ratios

    International Nuclear Information System (INIS)

    Modified 9Cr-1Mo steel T91, a candidate material for structural components in fission reactors, was irradiated with 3.5 MeV Fe ions at 450 °C to 150 displacements per atom. Transmission electron microscopy and scanning transmission electron microscopy were used to characterize the microstructure and microchemistry changes. We found that irradiation can induce formation of needle-like M3C particles, in addition to voids and tangled dislocations. But for these preexisting precipitates their compositions remain roughly the same before and after the irradiation. Furthermore, we did not observe either Cr depletion or Cr enrichment at grain and subgrain boundaries after the irradiation

  17. Studying Landslide Displacements in Megamendung (Indonesia Using GPS Survey Method

    Directory of Open Access Journals (Sweden)

    Hasanuddin Z. Abidin

    2004-11-01

    Full Text Available Landslide is one of prominent geohazards that frequently affects Indonesia, especially in the rainy season. It destroys not only environment and property, but usually also causes deaths. Landslide monitoring is therefore very crucial and should be continuously done. One of the methods that can have a contribution in studying landslide phenomena is repeated GPS survey method. This paper presents and discusses the operational performances, constraints and results of GPS surveys conducted in a well known landslide prone area in West Java (Indonesia, namely Megamendung, the hilly region close to Bogor. Three GPS surveys involving 8 GPS points have been conducted, namely on April 2002, May 2003 and May 2004, respectively. The estimated landslide displacements in the area are relatively quite large in the level of a few dm to a few m. Displacements up to about 2-3 m were detected in the April 2002 to May 2003 period, and up to about 3-4 dm in the May 2003 to May 2004 period. In both periods, landslides in general show the northwest direction of displacements. Displacements vary both spatially and temporally. This study also suggested that in order to conclude the existence of real and significant displacements of GPS points, the GPS estimated displacements should be subjected to three types of testing namely: the congruency test on spatial displacements, testing on the agreement between the horizontal distance changes with the predicted direction of landslide displacement, and testing on the consistency of displacement directions on two consecutive periods.

  18. Disruptions and vertical displacement events in JET

    International Nuclear Information System (INIS)

    Major disruptions and vertical displacement events (VDEs) represent a serious problem for the integrity of large devices such as ITER and a reactor. This arises from the localized power deposition on the divertor target and first wall, the production of runaway electrons in the post-disruptive plasma and the substantial forces transmitted to the vacuum vessel by eddy and halo currents. Extensive experiments have been performed in JET to characterize the phenomena associated with disruptions and VDEs and to investigate the underlying physics. In addition, the installation of a disruption feedback stabilization system based on a set of four internal saddle coils driven by high power (3 kA/1.5 kV), high frequency (0-10 kHz) amplifiers has allowed initial experiments on the control of disruptions by suppression of the n = 1 mhd precursor. This system has also been used to study fundamental aspects of the physics of error field induced modes, which is of direct application to ITER (author). 3 refs, 8 figs

  19. The Three Gorges: the unexamined toll of development-induced displacement

    Directory of Open Access Journals (Sweden)

    Martin Stein

    1998-04-01

    Full Text Available In China, the context of forced displacement in its broadest sense centres on four issues: (1 coercive displacement for development; (2 political persecution resulting in controlled displacement; (3 massive labour dislocations; and (4 disaster-induced displacement. This article looks at the role of the state in displacement, focusing on the first of these issues: development-induced displacement.

  20. Imaging screw dislocations at atomic resolution by aberration-corrected electron optical sectioning

    Science.gov (United States)

    Yang, H.; Lozano, J. G.; Pennycook, T. J.; Jones, L.; Hirsch, P. B.; Nellist, P. D.

    2015-06-01

    Screw dislocations play an important role in materials' mechanical, electrical and optical properties. However, imaging the atomic displacements in screw dislocations remains challenging. Although advanced electron microscopy techniques have allowed atomic-scale characterization of edge dislocations from the conventional end-on view, for screw dislocations, the atoms are predominantly displaced parallel to the dislocation line, and therefore the screw displacements are parallel to the electron beam and become invisible when viewed end-on. Here we show that screw displacements can be imaged directly with the dislocation lying in a plane transverse to the electron beam by optical sectioning using annular dark field imaging in a scanning transmission electron microscope. Applying this technique to a mixed [a+c] dislocation in GaN allows direct imaging of a screw dissociation with a 1.65-nm dissociation distance, thereby demonstrating a new method for characterizing dislocation core structures.

  1. 基于大涡模拟和Kirchhoff积分方法的孔腔流动发声机理分析%Analysis of the mechanism of cavity flow induced noise with large eddy simulation and Kirchhoff method integral

    Institute of Scientific and Technical Information of China (English)

    张楠; 沈泓萃; 朱锡清; 姚惠之

    2011-01-01

    孔腔流动与流激噪声是流声耦合研究领域的重要课题.文章基于大涡模拟方法与Kirchhoff积分,探讨了水中孔腔流动的发声机理.由孔腔流动振荡模态分析可知,在水中较低马赫数情况下,流体共振模态极难存在,故而流体动力振荡是产生孔腔流激噪声的根源,从而揭示了孔腔流激噪声形成的机理.进而又基于Kirchhoff控制面积分与物体壁面积分,辨识了偶极子声源和四极子声源对于流激噪声影响量级以及频谱分布规律,并结合流体动力声源的数学表达、Lighthill应力张量的频谱分析和壁面效应分析,指出了孔腔中涡旋对于流场脉动量声学效应的输运作用是孔腔流激噪声传播的成因,从而揭示了孔腔流激噪声传播的机理.%Cavity flow and flow induced noise are two important issues in the field of flow-acoustic coupling. The mechanism of cavity flow induced noise in water is studied by the large eddy simulation (LES)and Kirchhoff integral in this paper. The cavity flow oscillation analysis shows that the fluid-resonance mode is impossible in the condition of low Mach number in water, and the fluid-dynamic oscillation determines the generation of cavity flow induced noise. After that, the effects of dipole and quadrupole sources on the acoustic spectrum are identified according to Kirchhoff control surface integral and body surface integral. With the analysis of mathematical expression of acoustic source, the power spectrum of Lighthill stress tensor and wall influence,the radiation of flow induced noise should be attributed to the vortex transportation of the acoustic effect in fluctuations of unsteady flow.

  2. "Bohr's Atomic Model."

    Science.gov (United States)

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  3. Numerical simulations of displacement cascades in irradiated with intensive neutron flux iron

    Energy Technology Data Exchange (ETDEWEB)

    Nankov, N; Petrov, L; Popov, E; Troev, T, E-mail: nnankov@inrne.bas.b [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Science, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria)

    2010-01-01

    Numerical calculations of the radiation defects created in iron irradiated by fast neutrons (E > 0.1 MeV) were carried out. The total atom damages in iron at a neutron flux of 1.4x10{sup 15} n/cm{sup 2}s{sup -1} were determined to be 37.2 displacements per atom (dpa) per full power year (fpy). The helium concentration of 375 appm/fpy was obtained in irradiated iron for the same total neutron flux. A multi-scale numerical model has been developed in order to obtain better values for the neutron damages and the concentration of impurities. Using this approach the concentration of Fe, Mn and Cr isotopes as well as the concentration of helium and tritium has been determined as a result of the fast neutron irradiation.

  4. Numerical simulations of displacement cascades in irradiated with intensive neutron flux iron

    International Nuclear Information System (INIS)

    Numerical calculations of the radiation defects created in iron irradiated by fast neutrons (E > 0.1 MeV) were carried out. The total atom damages in iron at a neutron flux of 1.4x1015 n/cm2s-1 were determined to be 37.2 displacements per atom (dpa) per full power year (fpy). The helium concentration of 375 appm/fpy was obtained in irradiated iron for the same total neutron flux. A multi-scale numerical model has been developed in order to obtain better values for the neutron damages and the concentration of impurities. Using this approach the concentration of Fe, Mn and Cr isotopes as well as the concentration of helium and tritium has been determined as a result of the fast neutron irradiation.

  5. Displacive phase-transition of cuprite Ag2O revealed by extended x-ray absorption fine structure

    Science.gov (United States)

    Sanson, Andrea

    2016-08-01

    The low-temperature phase-transition of silver oxide (Ag2O) has been investigated by extended x-ray absorption fine structure (EXAFS) spectroscopy as a function of temperature. The thermal evolution of the local structure around Ag atoms has been determined. In particular, below the phase-transition temperature at ∼35 K, a progressive splitting of the Ag-Ag next-nearest-neighbor distances is observed. This definitely supports the idea that the phase-transition of Ag2O is due to displacive disorder of the Ag atoms.

  6. A compact system for single site atom loading of a neutral atom qubit array

    Science.gov (United States)

    Dinardo, Brad; Hughes, Steven; McBride, Sterling; Michalchuk, Joey; Anderson, Dana Z.

    2015-05-01

    We present progress towards single atom loading from a magneto optical trap reservoir to a bottle beam (BoB) array trap site for use in quantum computation. Our procedure involves vertically transporting cesium atoms via a moving molasses MOT from a 3D MOT chamber into a six sided, AR-coated, high optical access UHV science chamber. The cesium atoms are to be horizontally displaced 100 μm to a 7 × 7 array of blue-detuned BoB traps. Displacement of the atoms will be accomplished by means of a moving standing wave dipole trap. The single-site loading experiment will take place in the Atomic Qubit Array Cell (AQuA Cell) which is a compact, high performance UHV system that utilizes new miniature silicon and glass ion pump technology. The entire AQuA Cell is 0.6 liters. The cell, cooling, and transport optomechanics is incorporated in a package occupying about 0.028 cubic meters. Funding provided by IARPA MQCO.

  7. A Reference Optical System of Laser Doppler Longitudinal Displacement Measurement

    Institute of Scientific and Technical Information of China (English)

    张存满; 赵洋; 李达成

    2001-01-01

    In this paper, a new reference optical system is put forward to achieve longitudinal displacement measurement. An optical grating is used for frequency mixing and getting high SNR signals in the measurement. Conditions and methods for getting Doppler beat signals are presented.The experiments indicate that this optical syetem can be used to measure the longitudinal displacement with high accuracy.

  8. Employment protection and the consequences for displaced workers

    DEFF Research Database (Denmark)

    Albæk, Karsten; van Audenrode, Marc; Browning, Martin

    We compare the wage and employment consequences of a job displacement in Belgium and Denmark. These two countries both have generous unemployment insurance schemes but job protection laws vary dramatically between the two. Using comparable data we find that the incidence of displacement and the...

  9. Isothermal Gas assisted displacement of a polystyrene melt

    DEFF Research Database (Denmark)

    Eriksson, Torbjörn Gerhard; Rasmussen, Henrik K.

    2007-01-01

    Isothermal gas displacements of a polystyrene melt (shaped as circular cylinder with a radius of 2.5mm) placed inside a circular steel annulus were performed. A flow valve ensures a constant flow rate and rotational symmetric flow during the displacement. The experiments show an increase in the...

  10. Gas dynamic characteristic of displacer in Stirling cryocoolers

    Institute of Scientific and Technical Information of China (English)

    Xinguang LIU; Dongyu LIU; Yong WANG; Yinong WU

    2008-01-01

    Based on the vector analysis of the dynamic characteristic of the displacer in split-type Stirling cryo-coolers, experimental study was performed on a 2 W@80 K cooler to uncover the relationship among pressure fluctuation, damped impedance, inherent fre-quency, cold-tip temperature and the cooling perform-ance. The result shows that the pressure amplitude and phase shift between pressure and displacer motion decrease when the cooling temperature decreases; the dynamic damp of the displacer increases at lower cooling temperature, which results in the increase of pressure drop of the regenerator, the decrease of average pressure of the cold cubage, the decrease of gas dynamic pressure, the decrease of phase shift between pressure and displacer motion, and the displacement of the regenerator and the PV power; at lower cooling temperature, the inherent fre-quency of the displacer increases because of the augmen-tation of gas spring constant. And as the inherent frequency is getting closer to the operating frequency, the drive current of the motor decreases; the piston of the compressor affects the displacer by the pressure fluc-tuation engendered by its motion, and the displacer reacts by changing the mass and momentum distribution to adjust the gas spring constant and the damp coefficient.

  11. A displacement based FE formulation for steady state problems

    NARCIS (Netherlands)

    Yu, Yuhong

    2005-01-01

    In this thesis a new displacement based formulation is developed for elasto-plastic deformations in steady state problems. In this formulation the displacements are the primary variables, which is in contrast to the more common formulations in terms of the velocities as the primary variables. In a s

  12. Study on the applicability of the desk displacement ventilation concept

    NARCIS (Netherlands)

    Loomans, Marcel G.L.C.

    1999-01-01

    This paper summarizes an experimental and numerical study into a ventilation concept that combines displacement ventilation with task conditioning, the so-called desk displacement ventilation (DDV) concept. The study uses steady-state and transient results to discuss the applicability of the DDV con

  13. Displacement Ventilation in a Room with Low-Level Diffusers

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    Ventilation systems with vertical displacement flow have been used in industrial areas with high thermal loads for many years. Quite resently the vertical displacement flow systems have grown popular as comfort ventilation in rooms with thermal loads e.g. offices....

  14. Displacement and Force Measurements with Quadrant Photodetector in Optical Tweezers

    Institute of Scientific and Technical Information of China (English)

    郭红莲; 刘春香; 李兆霖; 段建发; 韩学海; 程丙英; 张道中

    2003-01-01

    A technique of displacement and force measurements with a photodiode quadrant detector in an optical tweezers system is presented. The stiffness of optical trap is calibrated and the leukemia cell membrane tension is measured.The results show that the optical tweezers combined with the quadrant detector is a very useful tool for detecting the displacement and force with a millisecond-order response.

  15. Hyoid Displacement in Post-Treatment Cancer Patients: Preliminary Findings

    Science.gov (United States)

    Zu, Yihe; Yang, Zhenyu; Perlman, Adrienne L.

    2011-01-01

    Purpose: Dysphagia after head and neck cancer treatment is a health care issue; in some cases, the cause of death is not cancer but, rather, the passage of food or liquid into the lungs. Hyoid displacement is known to be important to safe swallowing function. The purpose of this study was to evaluate hyoid displacement after cancer treatment.…

  16. Predicting target displacements using ultrasound elastography and finite element modeling

    NARCIS (Netherlands)

    Buijs, J.O. den; Hansen, H.H.G.; Lopata, R.G.P.; Korte, C.L. de; Misra, S.

    2011-01-01

    Soft tissue displacements during minimally invasive surgical procedures may cause target motion and subsequent misplacement of the surgical tool. A technique is presented to predict target displacements using a combination of ultrasound elastography and finite element (FE) modeling. A cubic gelatin/

  17. 48 CFR 952.226-74 - Displaced employee hiring preference.

    Science.gov (United States)

    2010-10-01

    ... Displaced employee hiring preference. As prescribed in 48 CFR (DEAR) 926.7104, insert the following clause. Displaced Employee Hiring Preference (JUN 1997) (a) Definition. Eligible employee means a current or former... preference. 952.226-74 Section 952.226-74 Federal Acquisition Regulations System DEPARTMENT OF ENERGY...

  18. An Evaluation of Neutron Energy Spectrum Effects in Iron Based on Molecular Dynamics Displacement Cascade Simulations

    International Nuclear Information System (INIS)

    The results of molecular dynamics (MD) displacement cascade simulations in bcc iron have been used to obtain effective cross sections for two measures of primary damage production: (1) the number of surviving point defects expressed as a fraction of the displacements calculated using the standard secondary displacement model of Norgett, Robinson, and Torrens (NRT), and (2) the fraction of the surviving interstitials contained in clusters that formed during the cascade event. Primary knockon atom spectra for iron obtained from the SPECTER code have been used to weight these MD-based damage production cross sections in order to obtain spectrally-averaged values for several locations in commercial fission reactors and materials test reactors. An evaluation of these results indicates that neutron energy spectrum differences between the various enviromnents do not lead to significant differences between the average primary damage formation parameters. In particular, the defect production cross sections obtained for PWR and BWR neutron spectra were not significantly different. The variation of the defect production cross sections as a function of depth into the reactor pressure vessel wall is used as a sample application of the cross sections. A slight difference between the attenuation behavior of the PWR and BWR was noted; this difference could be explained by a subtle difference in the energy dependence of the neutron spectra. Overall, the simulations support the continued use of dpa as a damage correlation parameter

  19. Diffusion behaviors of helium atoms at two Pd grain boundaries

    Institute of Scientific and Technical Information of China (English)

    XIA Ji-xing; HU Wang-yu; YANG Jian-yu; AO Bing-yun

    2006-01-01

    The diffusion behaviors of helium atoms at two symmetric grain boundaries (Σ5{210} and Σ3 {112}) of Pd were investigated using molecular dynamics simulations through an analytical embedded-atom method(MAEAM) model. The simulations demonstrate that the interstitial helium atoms are easily trapped at the grain boundaries and precipitated into clusters. Due to the closed-shell electronic configurations of both helium and palladium,Pd grain boundaries yield strong capability of retaining helium atoms. By calculating the mean square displacements(MSD) of an interstitial helium atom at the grain boundaries,the diffusion coefficients were determined,and the linear fits to Arrhenius relation. The diffusion activation energies of interstitial helium atom at these two Pd grain boundaries were also evaluated.

  20. Atomic Energy Basics, Understanding the Atom Series.

    Science.gov (United States)

    Atomic Energy Commission, Oak Ridge, TN. Div. of Technical Information.

    This booklet is part of the "Understanding the Atom Series," though it is a later edition and not included in the original set of 51 booklets. A basic survey of the principles of nuclear energy and most important applications are provided. These major topics are examined: matter has molecules and atoms, the atom has electrons, the nucleus,…

  1. Simultaneous sensing of displacement and temperature with a single FBG

    Institute of Scientific and Technical Information of China (English)

    WEI Ting; QIAO Xue-guang; JIA Zhen-an

    2011-01-01

    @@ A novel fiber Bragg grating (FBG) sensor with simultaneous sensing of displacement and temperature is presented.The FBG is affixed on the cantilever inclinedly.The midpoint of FBG exactly coincides with the zero strain layer of a rectangular beam.The vertical displacement can be measured by the broadened bandwidth of FBG as the bandwidth is insensitive to temperature, while the temperature can be measured by the center wavelength shift as the wavelength shift is insensitive to vertical displacement.With 0.1 nm spectral resolution of the analyzer, sensitivities of bandwidth-displacement and center wavelength-temperature are 0.48 nm/mm and 0.05 nm/℃, resolutions are 0.2 mm and 2.0 ℃, and sensing ranges of displacement and temperature are up to 8.5 mm and 45℃ respectively.Experimental results match theoretical analyses very well.

  2. POST TRAUMATIC DISPLACEMENT OF TESTIS- A RARE CASE REPORT

    Directory of Open Access Journals (Sweden)

    Avadhut

    2013-03-01

    Full Text Available ABSTRACT: Traumatic displacement of the testis is a rare occur rence and is defined as the displacement of one or both testis to a position othe r than the scrotum (1 .Traumatic displacement of testis is commonly a delayed diagnos is during treatment occurs as a consequence of high velocity road traffic accident (2 usually following a motorcycle collision, in what is referred to as "fuel tank injury”. Early id entification and subsequent surgical management is of utmost importance to maintain norm al spermatogenesis in the displaced testis. We report a case of traumatic displacement o f testis in superficial inguinal pouch in a young man presented 1 year after a road traffic acci dent. The clinical diagnosis was well supported by USG. The patient was successfully treated by inguinal exploration and repositioning of testis in scrotum, under spinal anes thesia.

  3. Synthetic-wavelength self-mixing interferometry for displacement measurement

    Science.gov (United States)

    Chen, Junbao; Zhu, Hongbin; Xia, Wei; Guo, Dongmei; Hao, Hui; Wang, Ming

    2016-06-01

    A simple synthetic-wavelength self-mixing interferometer is proposed for precision displacement measurement. Choosing the frequency difference of the orthogonally polarized dual frequency He-Ne laser appropriately, we introduce synthetic wavelength theory into self-mixing interference principle and demonstrate a feasible optical configuration by simply adjusting the optical design of self-mixing interferometer. The phase difference between the two orthogonally polarized feedback fringes is observed, and the tiny displacement of the object can be measured through the phase change of the synthetic signal. Since the virtual synthetic wavelength is 106 times larger than the operating wavelength, sub-nanometer displacement of the object can be obtained in millimeter criterion measurement without modulation, demodulation and complicated electrical circuits. Experimental results verifies the synthetic wavelength self-mixing interferometer's ability of measuring nanoscale displacement, which provides a potential approach for contactless precision displacement measurement in a number of scientific and industrial applications.

  4. Teach us atom structure

    International Nuclear Information System (INIS)

    This book is written to teach atom structure in very easy way. It is divided into nine chapters, which indicates what is the components of matter? when we divide matter continuously, it becomes atom, what did atom look like? particles comprised of matter is not only atom, discover of particles comprised of atom, symbol of element, various radiation, form alchemy to nuclear transmutation, shape of atom is evolving. It also has various pictures in each chapters to explain easily.

  5. Teach us atom structure

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Suh Yeon

    2006-08-15

    This book is written to teach atom structure in very easy way. It is divided into nine chapters, which indicates what is the components of matter? when we divide matter continuously, it becomes atom, what did atom look like? particles comprised of matter is not only atom, discover of particles comprised of atom, symbol of element, various radiation, form alchemy to nuclear transmutation, shape of atom is evolving. It also has various pictures in each chapters to explain easily.

  6. Electron-phonon coupling in Ni-based binary alloys with application to displacement cascade modeling.

    Science.gov (United States)

    Samolyuk, G D; Béland, L K; Stocks, G M; Stoller, R E

    2016-05-01

    Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron-phonon (el-ph) coupling. The el-ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states at the Fermi level, which in turn reduces the el-ph coupling. Thus, the el-ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10-20% in the alloys under consideration. PMID:27033732

  7. Electron–phonon coupling in Ni-based binary alloys with application to displacement cascade modeling

    International Nuclear Information System (INIS)

    Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron–phonon (el–ph) coupling. The el–ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states at the Fermi level, which in turn reduces the el–ph coupling. Thus, the el–ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10–20% in the alloys under consideration. (paper)

  8. Electron–phonon coupling in Ni-based binary alloys with application to displacement cascade modeling

    Science.gov (United States)

    Samolyuk, G. D.; Béland, L. K.; Stocks, G. M.; Stoller, R. E.

    2016-05-01

    Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron–phonon (el–ph) coupling. The el–ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states at the Fermi level, which in turn reduces the el–ph coupling. Thus, the el–ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10–20% in the alloys under consideration.

  9. A simplified methodology to estimate the displacement damage in both a copper stabilizer of TF coils and steel components of a fusion reactor

    International Nuclear Information System (INIS)

    This paper presents the results of calculations of fast neutron flux and displacement damage expressed as displacements per atom (dpa) number in stainless steel components of homogeneous steel-water shields. The changes of relations between the fast neutron flux and dpa number, which is a spectrum dependent parameter that amongst others serves as a design criterion of a fusion reactor project, versus the distance from the first wall are obtained for different water fractions in steel-water shields. A simplified analytical method to estimate the displacement damage in metal components of a fusion reactor is proposed. This method is expected to be used for simple and quick estimation of the displacement damage in metal components of a fusion reactor, for example the copper stabilizer of toroidal field coils and construction steel components of first walls, blankets etc. ((orig.))

  10. Atomic phase diagram

    Institute of Scientific and Technical Information of China (English)

    LI Shichun

    2004-01-01

    Based on the Thomas-Fermi-Dirac-Cheng model, atomic phase diagram or electron density versus atomic radius diagram describing the interaction properties of atoms of different kinds in equilibrium state is developed. Atomic phase diagram is established based on the two-atoms model. Besides atomic radius, electron density and continuity condition for electron density on interfaces between atoms, the lever law of atomic phase diagram involving other physical parameters is taken into account, such as the binding energy, for the sake of simplicity.

  11. Change in atomic coordination in a heavily deformed metallic glass

    International Nuclear Information System (INIS)

    The local structure around Ni and La atoms in Al85Ni10La5 amorphous powder after ball milling was investigated by X-ray absorption spectroscopy. A continuous decrease in coordination number of Ni and La as a function of milling time was observed, while the nearest neighbour distance and the mean square atomic displacement did not change, pointing at the creation of free volume around the Ni and La atoms. These structural changes resemble those of a liquid upon temperature increase. The results are described by a shear band model in which the coordination numbers of Ni and La are different within and outside a shear band.

  12. Displacement of the posterior part of the eyeball in myopia

    International Nuclear Information System (INIS)

    The principal aim of this study was to investigate displacement of the posterior part of the eyeball within the muscle cone in myopic eyes, particularly in moderately myopic subjects as well as in high myopes. Secondly, the correlation of the amount of displacement and the outer axial length of the globe was studied. The direction of displacement was also examined to clarify whether the eyeball tends to shift toward a certain direction. Seven patients with moderate myopia (moderate myopia group), fifteen patients with high myopia without esotropia (high myopia group), five patients with high myopia and esotropia (myopic esotropia group), and twenty-two controls (control group) were examined. Using magnetic resonance imaging, the outer axial length and the displacement of the posterior portion of the eyeball in the muscle cone were measured. In order to eliminate interindividual differences in the facial configuration, the coronal scanning was done perpendicularly to the orbital axis. The displacement was measured in a plane 4 mm anterior to the globe-optic nerve junction. The displacement was represented by the distance and direction of the globe center from the center of the muscle cone. In the moderate myopia group, there was no displacement of the posterior part of the eyeball in the muscle cone. It was the same as in the control group. But among the three groups, the displacement (mean±standard deviation) was significantly greater in the myopic esotropia group (1.53±0.49 mm) and the high myopia group (0.94±0.52 mm) than in the control group (0.11±0.18 mm) (one way ANOVA and multiple comparison). The outer axial length and the distance of the displacement in all cases was significantly correlated (r=0.87, p=0.01). Moreover, the posterior part of the eyeball of the myopic esotropia group and the high myopia group was displaced superiorly and temporally. The posterior part of the eyeball of myopic eyes was displaced superotemporally in the muscle cone

  13. MRI of radial displacement of the meniscus in the knee

    International Nuclear Information System (INIS)

    Objective: To describe the phenomenon of radial displacement of the meniscus of the knees in the study population with MR imaging, and to establish MRI diagnostic criteria for radial displacement of the meniscus and displacement index. Methods: MR signs of radial displacement of the meniscus were evaluated retrospectively in 398 patients with knee symptoms who were examined with non- weight bearing MR images from Jan. 2000 to Feb. 2004. The patients younger than 18 years old, with joint effusion or serious arthropathy were excluded and 312 patients were eligible to be enrolled in this study. The criterion for radial displacement of the meniscus was defined as the location of the edge of meniscal body beyond the femoral and tibial outer border line. A displacement index, defined as the ratio of meniscal overhang to meniscal width, was used to quantify meniscal displacement. Results: The prevalence of radial displacement of the meniscus was 16.7% (52/312) and 13.9% (21/151) in right knee and 19.3% (31/161 )in left knee, respectively. There was no significant difference between left and right knee (χ2=1.60, P>0.05) and the ratio between medial and lateral meniscus was 7.8:1. The average displacement index was 0.54±0.24. The displacement indices were significant higher in older group (F=3.63, P<0.05). The incidence and indices of radial displacement of the meniscus for patients under or above 50 year older were 12.0%(17/142), 0.46±0.22 and 20.6% (35/170), 0.64±0.20, respectively. Difference was highly significant (t=0.84, P<0.01). Conclusion: It was concluded that radial displacement of the meniscus in knees was not a rare finding with MR imaging in patients with knee symptoms. The incidence increased in older age group. Further investigations were recommended to understand the etiology and clinical significance of the phenomenon of radial displacement of the meniscus. (authors)

  14. Atomizer design for viscous-melt atomization

    Energy Technology Data Exchange (ETDEWEB)

    Czisch, C. [Chemical Engineering Department, University Bremen, Badgasteiner Str. 3, 28359 Bremen (Germany); Fritsching, U. [Chemical Engineering Department, University Bremen, Badgasteiner Str. 3, 28359 Bremen (Germany)], E-mail: ufri@iwt.uni-bremen.de

    2008-03-25

    The development of a gas atomization unit is introduced, which utilizes characteristic flow effects for efficient fragmentation of viscous liquids and melts. The proposed device combines a classical rotary atomizer with an external mixing gas atomizer. Here, the liquid stream is first transformed into a thin liquid sheet before disintegration. Thereby the specific surface energy is increased without breakup. The movement of the free flowing liquid film is controlled by the local gas flow field in order to transport the film into the most effective atomization region. The fragmentation process itself is caused by a perpendicular impinging gas stream. Numerical flow simulations are used for the development of the hybrid atomizer construction. Experiments using viscous model liquids show that for constant air-to-liquid mass-flow ratio the particle size is reduced using the hybrid atomizer compared with a conventional gas atomizer. Results of model experiments as well as of experiments with a viscous mineral melt are discussed.

  15. Atomizer design for viscous-melt atomization

    International Nuclear Information System (INIS)

    The development of a gas atomization unit is introduced, which utilizes characteristic flow effects for efficient fragmentation of viscous liquids and melts. The proposed device combines a classical rotary atomizer with an external mixing gas atomizer. Here, the liquid stream is first transformed into a thin liquid sheet before disintegration. Thereby the specific surface energy is increased without breakup. The movement of the free flowing liquid film is controlled by the local gas flow field in order to transport the film into the most effective atomization region. The fragmentation process itself is caused by a perpendicular impinging gas stream. Numerical flow simulations are used for the development of the hybrid atomizer construction. Experiments using viscous model liquids show that for constant air-to-liquid mass-flow ratio the particle size is reduced using the hybrid atomizer compared with a conventional gas atomizer. Results of model experiments as well as of experiments with a viscous mineral melt are discussed

  16. Cold Matter Assembled Atom-by-Atom

    CERN Document Server

    Endres, Manuel; Keesling, Alexander; Levine, Harry; Anschuetz, Eric R; Krajenbrink, Alexandre; Senko, Crystal; Vuletic, Vladan; Greiner, Markus; Lukin, Mikhail D

    2016-01-01

    The realization of large-scale fully controllable quantum systems is an exciting frontier in modern physical science. We use atom-by-atom assembly to implement a novel platform for the deterministic preparation of regular arrays of individually controlled cold atoms. In our approach, a measurement and feedback procedure eliminates the entropy associated with probabilistic trap occupation and results in defect-free arrays of over 50 atoms in less than 400 ms. The technique is based on fast, real-time control of 100 optical tweezers, which we use to arrange atoms in desired geometric patterns and to maintain these configurations by replacing lost atoms with surplus atoms from a reservoir. This bottom-up approach enables controlled engineering of scalable many-body systems for quantum information processing, quantum simulations, and precision measurements.

  17. A molecular-dynamics simulation of displacement cascades in α-iron

    International Nuclear Information System (INIS)

    A molecular-dynamics code has been developed for simulating the early process of radiation-induced defects generation and aggregation during displacement cascades in α-iron. This code reproduces the dynamics of various types of defects such as vacancies, interstitials, and their clusters in a crystal composed of a million atoms. Main procedures and results of the present simulation are as follows. Interactions among atoms were described by a many-body EAM potential. Every simulation was performed under 3D periodical boundary conditions. Cascades were introduced into crystals by giving a kinetic energy to a knock-on atom once at a time toward a crystallographic direction along low index axes i.e. , and axes. The maximum number of Frenkel-type defects was generated for a case when the knock-on direction was along axis. Interstitial atoms surrounding residual vacancies were observed to form several clusters shortly after pair annihilation of the Frenkel-type defects. Fast massive migration of the interstitial clusters was also observed. (author)

  18. Computer Modeling of Displacement Cascades in Beryllium Irradiated with Intensive Neutron Flux

    Directory of Open Access Journals (Sweden)

    T. Troev

    2008-02-01

    Full Text Available Computer simulations of the radiation defects created in beryllium irradiated by fast neutrons (E>0.1 MeV using the Geant4 and SRIM packages were carried out. The atom cascade displacements in Be at a neutron fluence of 1.6×1020 n/cm2 were determined to be 0.06 dpa and the helium concentration was calculated to be 168 appm. The concentration of L6i has been estimated to be 5% in comparison to the He concentration. Nanoscale calculations were done in 30×30×30 nm cube of fast neutron-irradiated Be. A correlation between the Be primary knock-on atom (PKA energies and the damage cascades has been established. The final defect distributions of single vacancies, divacancies, and small vacancy clusters were examined. Our results indicate that the damages caused by He atoms are about 3 times less than damages caused by Be primary knock-on atoms (PKAs.

  19. The role of environmental degradation in population displacement.

    Science.gov (United States)

    Lonergan, S

    1998-01-01

    This article answers a series of questions about the role of environmental degradation in population displacement, refugee movement, and migration. The environment tends not to be included in the reasons for migration. Roger's indicators of migration potential include population growth, economic restructuring, increased economic disparities, and increased refugee flows. Myers (1993) estimated that international displacement and internal displacement may amount to about 25 million and may rise to 150 million by 2050. The role of the environment in displacement must be examined in the broader political and cultural context. Definitions of environmental refugees are ambiguous and inconsistent, and research has not answered why people continue to move to Mexico City and Chongqing, China, which both have very high levels of pollution. El-Hinnawi (1985) defined 3 groups of environmental refugees: those displaced due to natural disasters; those displaced due to permanent habitat changes; and those displaced who migrated from areas that cannot support their basic needs and who desire an improved quality of life. Lonergan (1994) identified environmental stresses as natural disasters, cumulative or slow-onset changes, accidental disruptions or industrial accidents, development projects, and conflict and warfare. These 5 causes must be treated separately and not lumped together as environmental degradation. Shoreline erosion, coastal flooding, and agricultural disruption associated with climate change may increase migration. Global measures must address world poverty and promote sustainable development. PMID:12321719

  20. Measurement of chest wall displacement based on terahertz wave

    Science.gov (United States)

    Li, Hui; Lv, Hao; Jiao, Teng; Lu, Guohua; Li, Sheng; Li, Zhao; Liu, Miao; Jing, Xijing; Wang, Jianqi

    2015-02-01

    Measurement of chest wall displacement is an important approach for measuring mechanics of chest wall, which has considerable significance for assessing respiratory system and diagnosing pulmonary diseases. However, existing optical methods for measuring chest wall displacement are inconvenient for some specific patients such as the female patients and the patients with bandaged chest. In this letter, we proposed a method for measuring chest wall displacement based on terahertz wave and established corresponding mathematic model and set up a terahertz measurement system. The main advantages of this method are that it can measure the chest wall displacement of the subjects without taking off clothes or arranging any markers. To validate this method and assess the performance of the terahertz system, in vitro, the displacement of a water module driven by a linear guide rail was measured by the terahertz system and compared with the actual displacement of the water module. The results showed that the waveforms measured with two methods have a good agreement, and the relative error is less than 5% and sufficiently good for measurement demands. In vivo, the synchronous experiment was performed on five human volunteers with the terahertz system and a respiratory belt transducer. The results demonstrate that this method has good performance and promising prospects for measuring chest wall displacement.

  1. The Effect of Basepair Mismatch on DNA Strand Displacement.

    Science.gov (United States)

    Broadwater, D W Bo; Kim, Harold D

    2016-04-12

    DNA strand displacement is a key reaction in DNA homologous recombination and DNA mismatch repair and is also heavily utilized in DNA-based computation and locomotion. Despite its ubiquity in science and engineering, sequence-dependent effects of displacement kinetics have not been extensively characterized. Here, we measured toehold-mediated strand displacement kinetics using single-molecule fluorescence in the presence of a single basepair mismatch. The apparent displacement rate varied significantly when the mismatch was introduced in the invading DNA strand. The rate generally decreased as the mismatch in the invader was encountered earlier in displacement. Our data indicate that a single base pair mismatch in the invader stalls branch migration and displacement occurs via direct dissociation of the destabilized incumbent strand from the substrate strand. We combined both branch migration and direct dissociation into a model, which we term the concurrent displacement model, and used the first passage time approach to quantitatively explain the salient features of the observed relationship. We also introduce the concept of splitting probabilities to justify that the concurrent model can be simplified into a three-step sequential model in the presence of an invader mismatch. We expect our model to become a powerful tool to design DNA-based reaction schemes with broad functionality. PMID:27074674

  2. A method to calculate displacement factors using SVM

    Institute of Scientific and Technical Information of China (English)

    Li Peixian; Tan Zhixiang; Yan Lili; Deng Kazhong

    2011-01-01

    In order to improve the precision of mining subsidence prediction,a mathematical model using Support Vector Machine (SVM) was established to calculate the displacement factor.The study is based on a comprehensive analysis of factors affecting the displacement factor,such as mechanical properties of the cover rock,the ratio of mining depth to seam thickness,dip angle of the coal seam and the thickness of loose layer.Data of 63 typical observation stations were used as a training and testing sample set.A SVM regression model of the displacement factor and the factors affecting it was established with a kernel function,an insensitive loss factor and a properly selected penalty factor.Given an accurate calculation algorithm for testing and analysis,the results show that an SVM regression model can calculate displacement factor precisely and reliable precision can be obtained which meets engineering requirements.The experimental results show that the method to calculation of the displacement factor,based on the SVM method,is feasible.The many factors affecting the displacement factor can be considered with this method.The research provides an efficient and accurate approach for the calculation of displacement in mining subsidence prediction.

  3. A Study of Horizontal Displacement of Laterally Loaded Piles

    Directory of Open Access Journals (Sweden)

    Aram M. Raheem

    2013-05-01

    Full Text Available  A theoretical approach is used to analyze single pile and pile in group under lateral loading using two programs. The first one used the finite element method for single pile depending on plain strain condition while the second one used the characteristic load method for pile in group. Horizontal displacement for pile in group is measured while both horizontal displacement and shear stress for single pile are measured. A comparison between the results of horizontal displacement for both single pile and pile in group with the actual practical values are produced and shows a good agreement.

  4. Human response to ductless personalized ventilation coupled with displacement ventilation

    DEFF Research Database (Denmark)

    Dalewski, Mariusz; Veselý, Michal; Melikov, Arsen K.

    A human subject experiment was carried out to investigate the extent to which ductless personalized ventilation (DPV) in conjunction with displacement ventilation can improve perceived air quality (PAQ) and thermal comfort at elevated room air temperature in comparison with displacement ventilation......). During one hour exposure participants answered questionnaires regarding PAQ and thermal comfort. PAQ was significantly better with DPV than without DPV at the same background conditions. Thermal comfort improved when DPV was used. Combining DPV with displacement ventilation showed the potential for...... improving PAQ and thermal comfort when room air temperature is above the comfortable temperature range....

  5. The effect of Coulombic friction on spatial displacement statistics

    CERN Document Server

    Menzel, Andreas M

    2010-01-01

    The phenomenon of Coulombic friction enters the stochastic description of dry friction between two solids and the statistic characterization of vibrating granular media. Here we analyze the corresponding Fokker-Planck equation including both velocity and spatial components, exhibiting a formal connection to a quantum mechanical harmonic oscillator in the presence of a delta potential. Numerical solutions for the resulting spatial displacement statistics show a crossover from exponential to Gaussian displacement statistics. We identify a transient intermediate regime that exhibits multiscaling properties arising from the contribution of Coulombic friction. These results are relevant to recent experimental studies of the displacement of colloidal particles along bilayer membrane tubes.

  6. Measurement of local relative displacements in large structures

    DEFF Research Database (Denmark)

    Tesauro, Angelo; Eder, Martin Alexander; Nielsen, Magda

    2014-01-01

    and capable of measuring 3D local displacements with a high degree of accuracy. In this article, the technique is used to measure local deformations in the vicinity of the adhesive trailing edge joint of a wind turbine rotor blade. The SDMS results correspond well with another independent measurement...... particular. The measurement of small local relative displacements in structures subjected to large global deformations is complex and hardly feasible with conventional measurement methods. Therefore, a Small Displacement Measurement System (SDMS) has been devised. The SDMS is based on stereo photogrammetry...

  7. Shifting atomic patterns: on the origin of the different atomic-scale patterns of graphite as observed using scanning tunnelling microscopy

    International Nuclear Information System (INIS)

    We present an in-depth study of the myriad atomically resolved patterns observed on graphite using the scanning tunnelling microscope (STM) over the past three decades. Through the use of highly resolved atomic resolution images, we demonstrate how the interactions between the different graphene layers comprising graphite affect the local surface atomic charge density and its resulting symmetry orientation, with particular emphasis on interactions that are thermodynamically unstable. Moreover, the interlayer graphene coupling is controlled experimentally by varying the tip–surface interaction, leading to associated changes in the atomic patterns. The images are corroborated by first-principles calculations, further validating our claim that surface graphene displacement, coming both from lateral and vertical displacement of the top graphene layer, forms the basis of the rich variety of atomic patterns observed in STM experiments on graphite. (paper)

  8. Atomistic simulations of displacement cascades in Y{sub 2}O{sub 3} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Dholakia, Manan, E-mail: manan@igcar.gov.in [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India); Chandra, Sharat [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India); Valsakumar, M.C. [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500 046 (India); Mathi Jaya, S. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India)

    2014-11-15

    Graphical abstract: (a) The averaged distortion index and the Y–O bond length of the Y{sub 2}O{sub 3} octahedra as a function of the simulation time for 5 keV PKA. (b) Shows the nearest neighbourhood of one of the Y ions as a function of simulation time, showing the destruction and the recovery of the YO{sub 6} octahedron during the cascade corresponding to 5 keV Y PKA. - Highlights: • Qualitative difference in displacement cascades exists for Y and O PKA. • Nearest neighbour correlation between Y and O ions exists even at cascade peak. • Cascade core in Y{sub 2}O{sub 3} does not undergo melting. • Topological connectivity of YO{sub 6} polyhedra plays important role in stability of Y{sub 2}O{sub 3}. - Abstract: We study the characteristics of displacement cascades in single crystal Y{sub 2}O{sub 3} using classical molecular dynamics. There are two possible ways to generate the cascades in yttria, using either the Y or the O atoms as the primary knock-on (PKA) atom. It is shown that there is a qualitative difference in the characteristics of the cascades obtained in these two cases. Even though the crystal is seen to be in a highly disordered state in the cascade volume, as seen from the plots of radial distribution function, the correlation between the Y and O atoms is not completely lost. This facilitates a quick recovery of the system during the annealing phase. Topological connectivity of the YO{sub 6} polyhedral units plays an important role in imparting stability to the Y{sub 2}O{sub 3} crystal. These characteristics of the cascades can help explain the stability of the yttria nanoparticles when they are dispersed in oxide dispersion strengthened steels.

  9. Stable atomic hydrogen: Polarized atomic beam source

    International Nuclear Information System (INIS)

    We have carried out experiments with stable atomic hydrogen with a view to possible applications in polarized targets or polarized atomic beam sources. Recent results from the stabilization apparatus are described. The first stable atomic hydrogen beam source based on the microwave extraction method (which is being tested ) is presented. The effect of the stabilized hydrogen gas density on the properties of the source is discussed. (orig.)

  10. Neutral atom traps.

    Energy Technology Data Exchange (ETDEWEB)

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  11. MULTIPHOTON IONIZATION OF ATOMS

    OpenAIRE

    Mainfray, G.

    1985-01-01

    Multiphoton ionization of one-electron atoms, such as atomic hydrogen and alkaline atoms, is well understood and correctly described by rigorous theoretical models. The present paper will be devoted to collisionless multiphoton ionization of many-electron atoms as rare gases. It induces removal of several electrons and the production of multiply charged ions. Up to Xe5+ ions are produced in Xe atoms. Doubly charged ions can be produced, either by simultaneous excitation of two electrons, or b...

  12. Living in the shadows: internally displaced people in southern Africa

    Directory of Open Access Journals (Sweden)

    Marion Ryan Sinclair

    1998-04-01

    Full Text Available The Centre for Southern African Studies at the University of the Western Cape has recently begun a research project designed to investigate the extent, conditions and prognoses of internally displaced people (IDPs in southern African countries.

  13. Brake Pedal Displacement Measuring System based on Machine Vision

    Directory of Open Access Journals (Sweden)

    Chang Wang

    2013-10-01

    Full Text Available Displacement of brake pedal was an important characteristic of driving behavior. This paper proposed a displacement measure algorithm based on machine vision. Image of brake pedal was captured by camera from left side, and images were processed in industry computer. Firstly, average smooth algorithm and wavelet transform algorithm were used to smooth the original image consecutively. Then, edge extracting method which combined Roberts’s operator with wavelet analysis was used to identify the edge of brake pedal. At last, least square method was adopted to recognize the characteristic line of brake pedal’s displacement. The experimental results demonstrated that the proposed method takes the advantages of Roberts’s operator and wavelet transform, it can obtain better measurement result as well as linear displacement sensors

  14. Analytical Modeling for the Grating Eddy Current Displacement Sensors

    Directory of Open Access Journals (Sweden)

    Lv Chunfeng

    2015-02-01

    Full Text Available As a new type of displacement sensor, grating eddy current displacement sensor (GECDS combines traditional eddy current sensors and grating structure in one. The GECDS performs a wide range displacement measurement without precision reduction. This paper proposes an analytical modeling approach for the GECDS. The solution model is established in the Cartesian coordinate system, and the solving domain is limited to finite extents by using the truncated region eigenfunction expansion method. Based on the second order vector potential, expressions for the electromagnetic field as well as coil impedance related to the displacement can be expressed in closed-form. Theoretical results are then confirmed by experiments, which prove the suitability and effectiveness of the analytical modeling approach.

  15. Analysis of variance of an underdetermined geodetic displacement problem

    Energy Technology Data Exchange (ETDEWEB)

    Darby, D.

    1982-06-01

    It has been suggested recently that point displacements in a free geodetic network traversing a strike-slip fault may be estimated from repeated surveys by minimizing only those displacement components normal to the strike. It is desirable to justify this procedure. We construct, from estimable quantities, a deformation parameter which is an F-statistic of the type occurring in the analysis of variance of linear models not of full rank. A test of its significance provides the criterion to justify the displacement solution. It is also interesting to study its behaviour as one varies the supposed strike of the fault. Justification of a displacement solution using data from a strike-slip fault is found, but not for data from a rift valley. The technique can be generalized to more complex patterns of deformation such as those expected near the end-zone of a fault in a dislocation model.

  16. Evolution of specialization and ecological character displacement: metabolic plasticity matters.

    NARCIS (Netherlands)

    C.J.M. Egas

    2005-01-01

    An important question in evolutionary biology, especially with respect to herbivorous arthropods, is the evolution of specialization. In a previous paper, the combined evolutionary dynamics of specialization and ecological character displacement was studied, focusing on the role of herbivore foragin

  17. Effects of Displacement in Children Exposed to Disasters.

    Science.gov (United States)

    Pfefferbaum, Betty; Jacobs, Anne K; Van Horn, Richard L; Houston, J Brian

    2016-08-01

    The literature on children's responses to disasters is well developed with increasing attention to the confounding experiences of displacement. This paper presents an overview of the emotional and behavioral effects of displacement on children and adolescents and describes their educational adjustment in terms of both academic achievement and school behavior. A summary of family effects elucidates how children's functioning is influenced through the family system in which they are embedded. The psychosocial impact of displacement reflects the myriad social losses that children and their families may face. Information from this review of the current literature on the effects of displacement may inform the design and delivery of support and intervention services for children and families following disasters. PMID:27287465

  18. The displaced claiming their rights in fragile states

    OpenAIRE

    Antonia Mulvey

    2013-01-01

    To date, displaced persons in fragile and conflict-affected stateshave had little success in claiming their rights for housing, land andproperty violations. Creative legal thinking and strategic litigation has the potential to change this.

  19. Displaced Electric Sail Orbits Design and Transition Trajectory Optimization

    Directory of Open Access Journals (Sweden)

    Naiming Qi

    2014-01-01

    Full Text Available Displaced orbits for spacecraft propelled by electric sails are investigated as an alternative to the use of solar sails. The orbital dynamics of electric sails based spacecraft are studied within a spherical coordinate system, which permits finding the solutions of displaced electric sail orbits and optimize transfer trajectory. Transfer trajectories from Earth's orbit to displaced orbit are also studied in an optimal framework, by using genetic algorithm and Gauss pseudospectral method. The initial guesses for the state and control histories used in the Gauss pseudospectral method are interpolated from the best solution of a genetic algorithm. Numerical simulations show that the electric sail is able to perform the transfer from Earth’s orbit to displaced orbit in acceptable time, and the hybrid optimization method has the capability to search the feasible and optimal solution without any initial value guess.

  20. Two-state displacement by the kinesin-14 Ncd stalk

    OpenAIRE

    Hallen, Mark A; Liang, Zhang-Yi; Endow, Sharyn A.

    2011-01-01

    The nonprocessive kinesin-14 Ncd motor binds to microtubules and hydrolyzes ATP, undergoing a single displacement before releasing the microtubule. A lever-like rotation of the coiled-coil stalk is thought to drive Ncd displacements or steps along microtubules. Crystal structures and cryoelectron microscopy reconstructions imply that stalk rotation is correlated with ADP release and microtubule binding by the motor. Here we report FRET assays showing that the end of the stalk is more than ~9 ...

  1. Non-affine displacements in flexible polymer networks

    OpenAIRE

    Basu, Anindita; Wen, Qi; Mao, Xiaoming; Lubensky, T. C.; Janmey, Paul A.; Yodh, A. G.

    2010-01-01

    The validity of the affine assumption in model flexible polymer networks is explored. To this end, the displacements of fluorescent tracer beads embedded in polyacrylamide gels are quantified by confocal microscopy under shear deformation, and the deviations of these displacements from affine responses are recorded. Non-affinity within the gels is quantified as a function of polymer chain density and cross-link concentration. Observations are in qualitative agreement with current theories of ...

  2. Dispersive effects of transverse displacements of SLC Arc magnets

    International Nuclear Information System (INIS)

    The SLC Arc magnets are subject to random displacements and field errors resulting in unpredictable transverse displacement of the central trajectory from that of the design. The chosen method of correcting this perturbed trajectory in the SLC Arcs utilizes mechanical movement of the combined function magnets which compose the Arc transport lines. Here we present the results of a recent investigation substantiating the earlier results which led to the adoption of this method

  3. Adaptation and mental-hygienic characteristics of internally displaced adolescents

    OpenAIRE

    Maksimović Miloš; Kocijančić Radojka; Backović Dušan; Ille Tatjana; Paunović Katarina

    2005-01-01

    The change in socio-economic status, drastic decrease in living standards, war, and the introduction of sanctions to our country were complicated in addition by a large number of internally displaced people from Kosovo, which culminated with the 1999 NATO bombing. The aim of this investigation was to estimate the influence of internal displacement on the adaptation and mental health of adolescents. The investigation was conducted on 238 adolescents, comprising a control group of 206 adolescen...

  4. Forest transitions, trade, and the global displacement of land use

    OpenAIRE

    Meyfroidt, Patrick; Rudel, Thomas K.; Lambin, Eric

    2010-01-01

    Reducing tropical deforestation is an international priority, given its impacts on carbon emissions and biodiversity. We examined whether recent forest transitions—a shift from net deforestation to net reforestation—involved a geographic displacement of forest clearing across countries through trade in agricultural and forest products. In most of the seven developing countries that recently experienced a forest transition, displacement of land use abroad accompanied local reforestation. Addit...

  5. Displacement-Noise-Free Gravitational-Wave Detection

    OpenAIRE

    Kawamura, Seiji; Chen, Yanbei

    2004-01-01

    We present a new idea that allows us to detect gravitational waves without being disturbed by any kind of displacement noise, based on the fact that gravitational waves and test-mass motions affect the propagations of light differently. We demonstrate this idea by analyzing a simple toy model consisting three equally-separated objects on a line. By taking a certain combination of light travel times between these objects, we construct an observable free from the displacement of each object whi...

  6. Linear displacement measurement with a grating and speckle pattern illumination

    International Nuclear Information System (INIS)

    We present a study of the variations of a speckle pattern passing through a grating that can be displaced. This study is described theoretically by a simple model based on the scalar diffraction theory in the Fresnel zone. The intensity correlation of the modified speckle as a function of the grating displacement is obtained and compared with experimental results.The possibilities of metrological applications in optical encoders are suggested

  7. Linear displacement measurement with a grating and speckle pattern illumination

    Science.gov (United States)

    Perez-Quintián, Fernando; Lutenberg, Ariel; Rebollo, María A.

    2006-07-01

    We present a study of the variations of a speckle pattern passing through a grating that can be displaced. This study is described theoretically by a simple model based on the scalar diffraction theory in the Fresnel zone. The intensity correlation of the modified speckle as a function of the grating displacement is obtained and compared with experimental results. The possibilities of metrological applications in optical encoders are suggested.

  8. Urban revitalization and displacement: types, causes, and public policy

    Energy Technology Data Exchange (ETDEWEB)

    Feagin, J.R.

    1981-05-01

    The policy research report reviews the scholarly and print media literatures on urban revitalization. The extent of revitalization; the incumbent or occupant upgrading; gentrification (displacement of low- and moderate-income households by better-off households); gentrification and displacement from all causes; and the role of powerful actors in revitalization are discussed. Public policy dealing with land use and development in urban areas is discussed. Future research needs are indicated.

  9. Character displacement in the fighting colours of Hetaerina damselflies

    OpenAIRE

    Anderson, C. N; Grether, G. F.

    2010-01-01

    Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a pattern of character displacement (divergence in sympatry). A geographical survey of four Hetaerina damselfly species in Mexico and Texas showed evidenc...

  10. Origins of displacements caused by underground nuclear explosions

    International Nuclear Information System (INIS)

    Elastic theory has been used to calculate the relative displacement that will occur between the two sides of a loose boundary when a plane wave strikes the boundary obliquely. The calculations suggest that the displacements produced along loose fractures and faults close in to the underground nuclear explosions are a direct consequence of reflection of the transient stress wave at this loose boundary. Quantitatively the results agree fairly well with the limited data that are available. (author)

  11. MRI anatomy of anteriorly displaced anus: what obstructs defecation?

    Energy Technology Data Exchange (ETDEWEB)

    AbouZeid, Amr Abdelhamid [Ain-Shams University, Department of Pediatric Surgery, Cairo (Egypt); Mohammad, Shaimaa Abdelsattar; Khairy, Khaled Talaat [Ain-Shams University, Department of Radiodiagnosis, Cairo (Egypt)

    2014-07-15

    Anteriorly displaced anus is an anomaly that is debated with regard to its nomenclature, diagnosis and management. To describe MRI anatomy of the anal canal in children with anteriorly displaced anus and its impact on the process of defecation. We prospectively examined ten children (7 girls, 3 boys; age range 7 months to 8 years, mean 3 years) with anteriorly displaced anus between August 2009 and April 2012. Noncontrast MRI examinations were performed on a 1.5-T magnet. T1- and T2-weighted turbo spin-echo images were acquired in axial, sagittal and coronal planes of the pelvis. The anorectal angle and the relative hiatal distance were measured in mid-sagittal images, and compared with those of a control group using the Mann-Whitney test. In children with anteriorly displaced anus, no anatomical abnormality was depicted at the level of the proximal anal canal. However, the distal anal canal was displaced anteriorly, running out its external muscle cuff, which remained un-displaced at the usual site of the anus. This changes the orientation of the central axis of the anal canal by passing across instead of along the fibers of the longitudinal muscle coat. Children with anteriorly displaced anus had a more obtuse anorectal angle (mean 112.1 ), which was significantly greater than that of the control group (mean 86.2 ). MRI is a valuable tool in studying the anatomy of the anal canal in children with anteriorly displaced anus. The abnormal orientation of the longitudinal muscle across the anal canal can explain the obstructed defecation in these children. Based on this study, it might be of interest to use MRI in studying equivocal cases and children with unexplained constipation. (orig.)

  12. Software for determining the true displacement of faults

    Science.gov (United States)

    Nieto-Fuentes, R.; Nieto-Samaniego, Á. F.; Xu, S.-S.; Alaniz-Álvarez, S. A.

    2014-03-01

    One of the most important parameters of faults is the true (or net) displacement, which is measured by restoring two originally adjacent points, called “piercing points”, to their original positions. This measurement is not typically applicable because it is rare to observe piercing points in natural outcrops. Much more common is the measurement of the apparent displacement of a marker. Methods to calculate the true displacement of faults using descriptive geometry, trigonometry or vector algebra are common in the literature, and most of them solve a specific situation from a large amount of possible combinations of the fault parameters. True displacements are not routinely calculated because it is a tedious and tiring task, despite their importance and the relatively simple methodology. We believe that the solution is to develop software capable of performing this work. In a previous publication, our research group proposed a method to calculate the true displacement of faults by solving most combinations of fault parameters using simple trigonometric equations. The purpose of this contribution is to present a computer program for calculating the true displacement of faults. The input data are the dip of the fault; the pitch angles of the markers, slickenlines and observation lines; and the marker separation. To prevent the common difficulties involved in switching between operative systems, the software is developed using the Java programing language. The computer program could be used as a tool in education and will also be useful for the calculation of the true fault displacement in geological and engineering works. The application resolves the cases with known direction of net slip, which commonly is assumed parallel to the slickenlines. This assumption is not always valid and must be used with caution, because the slickenlines are formed during a step of the incremental displacement on the fault surface, whereas the net slip is related to the finite slip.

  13. A novel approach to modeling unstable EOR displacements. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Peters, E.J.

    1994-04-01

    Most enhanced oil recovery schemes involve the displacement of a more dense and more viscous oil by a less dense and less viscous fluid in a heterogeneous porous medium. The interaction of heterogeneity with the several competing forces, namely, viscous, capillary, gravitational, and dispersive forces, can conspire to make the displacements unstable and difficult to model and to predict. The objective of this research was to develop a systematic methodology for modeling unstable fluid displacements in heterogeneous media. Flow visualization experiments were conducted using X-ray computed tomography imaging and a video imaging workstation to gain insights into the dynamics of unstable displacements, acquire detailed quantitative experimental image data for calibrating numerical models of unstable displacements, and image and characterize heterogeneities in laboratory cores geostatistically. High-resolution numerical models modified for use on vector-architecture supercomputers were used to replicate the image data. Geostatistical models of reservoir heterogeneity were incorporated in order to study the interaction of hydrodynamic instability and heterogeneity in reservoir displacements. Finally, a systematic methodology for matching the experimental data with the numerical models and scaling the laboratory results to other systems were developed. The result is a new method for predicting the performance of unstable EOR displacements in the field based on small-scale displacements in the laboratory. The methodology is general and can be applied to forecast the performance of most processes that involve fluid flow and transport in porous media. Therefore, this research should be of interest to those involved in forecasting the performance of enhanced oil recovery processes and the spreading of contaminants in heterogeneous aquifers.

  14. Yes, And... The Improvising Landscape of the Displaced

    OpenAIRE

    Javaherigilani, Eliana

    2016-01-01

    Immigration has continuously been an evident part of the human history. Throughout time, for one reason or another people have left the place they call home. Whether voluntarily seeking better opportunities in other cities/countries/continents, or forcefully being asked to leave due to political, social, or natural issues, resettlement continues to be a difficult challenge for those who are displaced. The issue, human displacement, whether caused by natural disasters or political/social ...

  15. Million atom DFT calculations using coarse graining and petascale computing

    Science.gov (United States)

    Nicholson, Don; Odbadrakh, Kh.; Samolyuk, G. D.; Stoller, R. E.; Zhang, X. G.; Stocks, G. M.

    2014-03-01

    Researchers performing classical Molecular Dynamics (MD) on defect structures often find it necessary to use millions of atoms in their models. It would be useful to perform density functional calculations on these large configurations in order to observe electron-based properties such as local charge and spin and the Helmann-Feynman forces on the atoms. The great number of atoms usually requires that a subset be ``carved'' from the configuration and terminated in a less that satisfactory manner, e.g. free space or inappropriate periodic boundary conditions. Coarse graining based on the Locally Self-consistent Multiple Scattering method (LSMS) and petascale computing can circumvent this problem by treating the whole system but dividing the atoms into two groups. In Coarse Grained LSMS (CG-LSMS) one group of atoms has its charge and scattering determined prescriptively based on neighboring atoms while the remaining group of atoms have their charge and scattering determined according to DFT as implemented in the LSMS. The method will be demonstrated for a one-million-atom model of a displacement cascade in Fe for which 24,130 atoms are treated with full DFT and the remaining atoms are treated prescriptively. Work supported as part of Center for Defect Physics, an Energy Frontier Research Center funded by the U.S. DOE, Office of Science, Basic Energy Sciences, used Oak Ridge Leadership Computing Facility, Oak Ridge National Lab, of DOE Office of Science.

  16. Technique for Determining Bridge Displacement Response Using MEMS Accelerometers.

    Science.gov (United States)

    Sekiya, Hidehiko; Kimura, Kentaro; Miki, Chitoshi

    2016-01-01

    In bridge maintenance, particularly with regard to fatigue damage in steel bridges, it is important to determine the displacement response of the entire bridge under a live load as well as that of each member. Knowing the displacement response enables the identification of dynamic deformations that can cause stresses and ultimately lead to damage and thus also allows the undertaking of appropriate countermeasures. In theory, the displacement response can be calculated from the double integration of the measured acceleration. However, data measured by an accelerometer include measurement errors caused by the limitations of the analog-to-digital conversion process and sensor noise. These errors distort the double integration results. Furthermore, as bridges in service are constantly vibrating because of passing vehicles, estimating the boundary conditions for the numerical integration is difficult. To address these problems, this paper proposes a method for determining the displacement of a bridge in service from its acceleration based on its free vibration. To verify the effectiveness of the proposed method, field measurements were conducted using nine different accelerometers. Based on the results of these measurements, the proposed method was found to be highly accurate in comparison with the reference displacement obtained using a contact displacement gauge. PMID:26907287

  17. Technique for Determining Bridge Displacement Response Using MEMS Accelerometers

    Directory of Open Access Journals (Sweden)

    Hidehiko Sekiya

    2016-02-01

    Full Text Available In bridge maintenance, particularly with regard to fatigue damage in steel bridges, it is important to determine the displacement response of the entire bridge under a live load as well as that of each member. Knowing the displacement response enables the identification of dynamic deformations that can cause stresses and ultimately lead to damage and thus also allows the undertaking of appropriate countermeasures. In theory, the displacement response can be calculated from the double integration of the measured acceleration. However, data measured by an accelerometer include measurement errors caused by the limitations of the analog-to-digital conversion process and sensor noise. These errors distort the double integration results. Furthermore, as bridges in service are constantly vibrating because of passing vehicles, estimating the boundary conditions for the numerical integration is difficult. To address these problems, this paper proposes a method for determining the displacement of a bridge in service from its acceleration based on its free vibration. To verify the effectiveness of the proposed method, field measurements were conducted using nine different accelerometers. Based on the results of these measurements, the proposed method was found to be highly accurate in comparison with the reference displacement obtained using a contact displacement gauge.

  18. Pattern of dynamic displacements in a strike-slip earthquake

    Science.gov (United States)

    Saltogianni, V.; Gianniou, M.; Moschas, F.; Stiros, S.

    2016-07-01

    High-rate (1 Hz) records from GPS stations uniformly distributed along the fault ruptures of the 2014 Samothraki-Gökçeada Mw6.9 earthquake in the North Aegean Trough, at the extension of the North Anatolian Fault Zone, were analyzed using the Precise Point Positioning (PPP) technique. Computed dynamic displacements shed light to the pattern of dynamic displacements during shallow strike-slip earthquakes. The area of near-field static seismic displacements bounds ramp-type, long-period dynamic displacements (fling steps) in the sense of static displacements. Along-fault and normal to fault components of dynamic displacement follow typical attenuation laws, but attenuation is higher in the fault-parallel component hence confined to the area of static dislocations. Forward directivity and local, especially topography-controlled amplification effects, consistent with accelerometer evidence, were also observed. The overall pattern seems to characterize shallow strike-slip earthquakes and is expected to prove useful to explain or even predict the near-field damaging potential of strike-slip earthquakes.

  19. Additional longitudinal displacement for contaminant dispersion in wetland flow

    Science.gov (United States)

    Fu, Xudong; Gao, Ran; Wu, Zi

    2016-01-01

    When there is a sudden and uniform release of contaminant over the depth of wetland, the centroid of resulted solute cloud will travel downstream at the cross-sectional mean velocity of the flow. However, if the initial release is not uniform, there will be an additional longitudinal displacement of the centroid, which is important for predicting the concentration distribution but cannot be revealed by the classical one-dimensional Taylor dispersion model. For the most typical case of an initial point source release at the free-water-surface of the wetland, an idealized case modeling accidental leakage of toxic chemicals in waters, in the present paper we analytically deduce the longitudinal displacement by the method of concentration moment. The result is then incorporated in the analytical solutions of concentration distribution, which are further verified by our numerical simulations. The effects of the longitudinal displacement on the concentration distribution are analyzed in detail. It is shown that without considering the displacement, for vertical planes close to the edges of the contaminant cloud, the analytical solution can over- or under-estimate the vertical distribution of concentration for over 20% of the maximum concentration in the plane even at a large dimensionless time of t∗ = 5 . The longitudinal displacement is shown to decrease with the increase of the important damping factor α, which characterizes the effects of vegetation in wetlands. A simple application is given at the end of this paper to illustrate the evolution of the additional longitudinal displacement.

  20. A wireless laser displacement sensor node for structural health monitoring.

    Science.gov (United States)

    Park, Hyo Seon; Kim, Jong Moon; Choi, Se Woon; Kim, Yousok

    2013-01-01

    This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM). The proposed measurement system consists of a laser displacement sensor (LDS) and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA) communication module, a processor, and a power module. An LDS with a long measurement distance is chosen to increase field applicability. For a wireless sensor node driven by a battery, we use a power control module with a low-power processor, which facilitates switching between the sleep and active modes, thus maximizing the power consumption efficiency during non-measurement and non-transfer periods. The CDMA mode is also used to overcome the limitation of communication distance, which is a challenge for wireless sensor networks and wireless communication. To evaluate the reliability and field applicability of the proposed wireless displacement measurement system, the system is tested onsite to obtain the required vertical displacement measurements during the construction of mega-trusses and an edge truss, which are the primary structural members in a large-scale irregular building currently under construction. The measurement values confirm the validity of the proposed wireless displacement measurement system and its potential for use in safety evaluations of structural elements. PMID:24084114

  1. On the evolution of superposition of squeezed displaced number states with the multiphoton Jaynes-Cummings model

    CERN Document Server

    El-Orany, Faisal A A

    2009-01-01

    In this paper we discuss the quantum properties for superposition of squeezed displaced number states against multiphoton Jaynes-Cummings model (JCM). In particular, we investigate atomic inversion, photon-number distribution, purity, quadrature squeezing, Mandel $Q$ parameter and Wigner function. We show that the quadrature squeezing for three-photon absorption case can exhibit revivals and collapses typical to those occurring in the atomic inversion for one-photon absorption case. Also we prove that for odd number absorption parameter there is a connection between the evolution of the atomic inversion and the evolution of the Wigner function at the origin in phase space. Furthermore, we show that the nonclassical states whose the Wigner functions values at the origins are negative will be always nonclassical when they are evolving through the JCM with even absorption parameter. Also we demonstrate that various types of cat states can be generated via this system.

  2. Atomistic Simulations of Displacement Cascades in Fused Silica: It is Compared with Different Concentration of H in the Bulk

    International Nuclear Information System (INIS)

    Amorphous Silica is one of candidate materials for both final focusing optics of lasers for NIF and future inertial fusion reactors and diagnostics of the Safety and Control Systems of the ITER machine as well as DEMO magnetic fusion reactors. In operation, these materials will be exposed to high neutron irradiation fluxes and it can result in point defect and vary the optical absorption, that is, degradation of the optical properties. In this paper we present molecular dynamic simulation of displacement cascade due to energetic recoils in amorphous silica without hydrogen atoms and with 1% of hydrogen atoms trying to identify defects formation. We have made a statistics of the different kind of defects at different energy of primary knock-on atoms (PKA). The range of studied PKA energies are from 400 eV to 3.5 keV and it is made to both component of this material Silicon and Oxygen. (authors)

  3. Atomic and molecular manipulation

    CERN Document Server

    Mayne, Andrew J

    2011-01-01

    Work with individual atoms and molecules aims to demonstrate that miniaturized electronic, optical, magnetic, and mechanical devices can operate ultimately even at the level of a single atom or molecule. As such, atomic and molecular manipulation has played an emblematic role in the development of the field of nanoscience. New methods based on the use of the scanning tunnelling microscope (STM) have been developed to characterize and manipulate all the degrees of freedom of individual atoms and molecules with an unprecedented precision. In the meantime, new concepts have emerged to design molecules and substrates having specific optical, mechanical and electronic functions, thus opening the way to the fabrication of real nano-machines. Manipulation of individual atoms and molecules has also opened up completely new areas of research and knowledge, raising fundamental questions of "Optics at the atomic scale", "Mechanics at the atomic scale", Electronics at the atomic scale", "Quantum physics at the atomic sca...

  4. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    2000-01-01

    This fifth volume of the successful series Advances in Atomic Spectroscopy continues to discuss and investigate the area of atomic spectroscopy.It begins with a description of the use of various atomic spectroscopic methods and applications of speciation studies in atomic spectroscopy. The emphasis is on combining atomic spectroscopy with gas and liquid chromatography. In chapter two the authors describe new developments in tunable lasers and the impact they will have on atomic spectroscopy. The traditional methods of detection, such as photography and the photomultiplier, and how they are being replaced by new detectors is discussed in chapter three. The very active area of glow discharge atomic spectrometry is presented in chapter four where, after a brief introduction and historical review, the use of glow discharge lamps for atomic spectroscopy and mass spectrometry are discussed. Included in this discussion is geometry and radiofrequency power. The future of this source in atomic spectroscopy is also dis...

  5. Beam steering and coordinate system rotation improves accuracy of ultrasonic measurements of tissue displacement vector and lateral displacement

    Directory of Open Access Journals (Sweden)

    Sumi C

    2011-11-01

    Full Text Available Chikayoshi Sumi1,2, Kento Ichimaru2, Yusuke Shinozuka21Department of Information and Communication Science, 2Department of Electrical and Electronics Engineering, Faculty of Science and Technology, Sophia University, Kioi-cho, Chiyoda-ku, Tokyo, JapanAbstract: With the proper use of beam steering and apodization, a higher resolution lateral echo image is obtained than with conventional imaging. This is achieved by superimposing crossed, steered beams, which is referred to as “lateral modulation” (LM. This type of beamforming achieves almost the same accuracy in lateral displacement measurements as in axial displacement measurements, ie, displacement vector measurements. The steering angle (ASTA can also be used instead of LM, which uses only beams with a steering angle. In this report, the accuracy of the displacement vectors and lateral displacement measurements for LM and ASTA were evaluated using simulations and agar phantom experiments. The parameters used were direction of a displacement vector, steering angles, and rotation angle for the coordinate system. Changes in the steering angle and rotation angle of the coordinate system permit control of frequencies in the respective directions of the coordinate axes. As shown, when performing a simple ASTA for displacement vector measurement, a spectra frequency division should be performed using a previously developed multidimensional autocorrelation or Doppler method instead of block-matching methods. In this version of ASTA, the combination of nonsteering and rotation of the coordinate system is also effective, because the lateral bandwidth does not decrease. In such a case, transmission of a laterally wide wave will also be effective, particularly for three-dimensional measurement/imaging using a two-dimensional array transducer. ASTA can also be used for accurate lateral displacement measurements. Although a proper beam steering and/or a proper coordinate rotation improves the

  6. THE ORNL ATOM PROBE

    OpenAIRE

    Miller, M

    1986-01-01

    The ORNL Atom Probe is a microanalytical tool for studies in materials science. The instrument is a combination of a customized version of the vacuum system of the VG FIM-100 atom probe, an ORNL-designed microcomputer-controlled digital timing system, and a double curved CEMA Imaging Atom Probe detector. The atom probe combines four instruments into one - namely a field ion microscope, an energy compensated time-of-flight mass spectrometer, an imaging atom probe, and a pulsed laser atom probe.

  7. Athermalization in atomic force microscope based force spectroscopy using matched microstructure coupling

    OpenAIRE

    Torun, H.; Finkler, O.; Degertekin, F. L.

    2009-01-01

    The authors describe a method for athermalization in atomic force microscope (AFM) based force spectroscopy applications using microstructures that thermomechanically match the AFM probes. The method uses a setup where the AFM probe is coupled with the matched structure and the displacements of both structures are read out simultaneously. The matched structure displaces with the AFM probe as temperature changes, thus the force applied to the sample can be kept constant without the need for a ...

  8. Steering of H- ion beamlet by aperture displacement

    International Nuclear Information System (INIS)

    Focussing of multibeamlets produced from a large accelerator grid is a key issue of ion beam application to the neutral beam injector (NBI) of fusion devices. Another issue is highlighted in a case of negative ion based NBI to compensate beamlet deflection inside the extractor, where magnetic field is applied for suppression of electron extraction. Steering of H- beamlet was carried out by displacing apertures in an electrostatic extractor/accelerator composed of four grids, where the beam energy was in the range of ∼50 keV. Out of a few combination of grid displacement, displacement of ESG (3rd grid) and/or GRG (4th grid) was found to be successful: 1) The beamlet steering angle of 50 mrad was obtained by displacing the apertures of 9 mm dia. up to 3 mm. It was confirmed that the steering angle was proportional fairly well to the displacement. The characteristic of the steering, i.e., the steering angle as a function of displacement, agrees well with the analysis based on the linear optics theory. 2) Neither significant divergence growth nor the beam interception were observed in the steered beams over a wide range of operation. The H- beams, of which divergent angle was 5 mrad, was obtained even under the beamlet steering. Thus the steering by displacement is suitable for the focusing of negative ion beam generated from multi-aperture grids. 3) It was found that the steering angle was independent of the magnetic field direction in the present extractor structure. This is an advantage of the steering technique for compensation of the beam deflection inside the extractor by magnetic field. (author)

  9. Replication of mitochondrial DNA occurs by strand displacement with alternative light-strand origins, not via a strand-coupled mechanism

    OpenAIRE

    Brown, Timothy A.; Cecconi, Ciro; Tkachuk, Ariana N.; Bustamante, Carlos; Clayton, David A.

    2005-01-01

    The established strand-displacement model for mammalian mitochondrial DNA (mtDNA) replication has recently been questioned in light of new data using two-dimensional (2D) agarose gel electrophoresis. It has been proposed that a synchronous, strand-coupled mode of replication occurs in tissues, thereby casting doubt on the general validity of the “orthodox,” or strand-displacement model. We have examined mtDNA replicative intermediates from mouse liver using atomic force microscopy and 2D agar...

  10. Mathematical modeling of nanomachining with atomic force microscope cantilevers

    International Nuclear Information System (INIS)

    This article theoretically analyzes the cutting depth and material removal rate of an atomic force microscope (AFM) cantilever during nanomachining. An analytical expression for the vibration frequency and displacement of the cantilever has been obtained by using the modified couple stress theory. The theory includes one additional material length scale parameter revealing the micro-scale effect. According to the analysis, the results show that the effect of size-dependent on the vibration behavior of the AFM cantilever is obvious. The maximum displacement of nanomachining with the AFM cantilever represents the cutting depth. The area under the displacement-time curve is related to the material removal rate. When the excitation frequency is closer to the nature frequency of the cantilever, a larger material removal rate is obtained

  11. Characteristics of children with hip displacement in cerebral palsy

    Directory of Open Access Journals (Sweden)

    Wagner Philippe

    2007-10-01

    Full Text Available Abstract Background Hip dislocation in children with cerebral palsy (CP is a common and severe problem. The dislocation can be avoided, by screening and preventive treatment of children with hips at risk. The aim of this study was to analyse the characteristics of children with CP who develop hip displacement, in order to optimise a hip surveillance programme. Methods In a total population of children with CP a standardised clinical and radiological follow-up of the hips was carried out as a part of a hip prevention programme. The present study is based on 212 children followed until 9–16 years of age. Results Of the 212 children, 38 (18% developed displacement with Migration Percentage (MP >40% and further 19 (9% MP between 33 and 39%. Mean age at first registration of hip displacement was 4 years, but some hips showed MP > 40% already at two years of age. The passive range of hip motion at the time of first registration of hip displacement did not differ significantly from the findings in hips without displacement. The risk of hip displacement varied according to CP-subtype, from 0% in children with pure ataxia to 79% in children with spastic tetraplegia. The risk of displacement (MP > 40% was directly related to the level of gross motor function, classified according to the gross motor function classification system, GMFCS, from 0% in children in GMFCS level I to 64% in GMFCS level V. Conclusion Hip displacement in CP often occurs already at 2–3 years of age. Range of motion is a poor indicator of hips at risk. Thus early identification and early radiographic examination of children at risk is of great importance. The risk of hip displacement varies according to both CP-subtype and GMFCS. It is sometimes not possible to determine subtype before 4 years of age, and at present several definitions and classification systems are used. GMFCS is valid and reliable from 2 years of age, and it is internationally accepted. We recommend a hip

  12. Atomic and molecular structure

    International Nuclear Information System (INIS)

    This book is a textbook for an introductory course of atomic physics for students of chemistry. After an introduction to the mathematical and physical foundations the quantum mechanical theory of atoms is described starting from simple examples of quantum mechanics. Then the atomic structure and the chemical bending are extensively discussed. This book is also suited for physicists who are especially interested in the atomic structure and the theory of chemical reactions. (HSI)

  13. Atomic Scale Plasmonic Switch

    OpenAIRE

    Emboras, A.; Niegemann, J.; Ma, P; Haffner, C; Pedersen, A.; Luisier, M.; Hafner, C; Schimmel, T.; Leuthold, J.

    2016-01-01

    The atom sets an ultimate scaling limit to Moore’s law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocat...

  14. Atomizing nozzle and process

    Science.gov (United States)

    Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.

    1992-06-30

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  15. Antiprotonic Helium Atoms

    OpenAIRE

    Kartavtsev, O. I.

    1995-01-01

    Metastable antiprotonic helium atoms $^{3,4}\\! H\\! e\\bar pe$ have been discovered recently in experiments of the delayed annihilation of antiprotons in helium media. These exotic atoms survive for an enormous time (about tens of microseconds) and carry the extremely large total angular momentum $L\\sim 30-40$. The theoretical treatment of the intrinsic properties of antiprotonic helium atoms, their formation and collisions with atoms and molecules is discussed.

  16. Atoms Talking to SQUIDs

    OpenAIRE

    2011-01-01

    We present a scheme to couple trapped $^{87}$Rb atoms to a superconducting flux qubit through a magnetic dipole transition. We plan to trap atoms on the evanescent wave outside an ultrathin fiber to bring the atoms to less than 10 $\\mu$m above the surface of the superconductor. This hybrid setup lends itself to probing sources of decoherence in superconducting qubits. Our current plan has the intermediate goal of coupling the atoms to a superconducting LC resonator.

  17. A relative nodal displacement method for element nonlinear analysis

    International Nuclear Information System (INIS)

    Nodal displacements are referred to the initial configuration in the total Lagrangian formulation and to the last converged configuration in the updated Lagrangian formulation. This research proposes a relative nodal displacement method to represent the position and orientation for a node in truss structures. Since the proposed method measures the relative nodal displacements relative to its adjacent nodal reference frame, they are still small for a truss structure undergoing large deformations for the small size elements. As a consequence, element formulations developed under the small deformation assumption are still valid for structures undergoing large deformations, which significantly simplifies the equations of equilibrium. A structural system is represented by a graph to systematically develop the governing equations of equilibrium for general systems. A node and an element are represented by a node and an edge in graph representation, respectively. Closed loops are opened to form a spanning tree by cutting edges. Two computational sequences are defined in the graph representation. One is the forward path sequence that is used to recover the Cartesian nodal displacements from relative nodal displacement sand traverses a graph from the base node towards the terminal nodes. The other is the backward path sequence that is used to recover the nodal forces in the relative coordinate system from the known nodal forces in the absolute coordinate system and traverses from the terminal nodes towards the base node. One open loop and one closed loop structure undergoing large deformations are analyzed to demonstrate the efficiency and validity of the proposed method

  18. Characterization of the elastic displacement demand: Case study - Sofia city

    International Nuclear Information System (INIS)

    The results of the study on the seismic site response in a part of the metropolitan Sofia are discussed. The neo-deterministic seismic hazard assessment procedure has been used to compute realistic synthetic waveforms considering four earthquake scenarios, with magnitudes M = 3.7, M = 6.3 and M = 7.0. Source and site specific ground motion time histories are computed along three investigated cross sections, making use of the hybrid approach, combining the modal summation technique and the finite differences scheme. Displacement and acceleration response spectra are considered. These results are validated against the design elastic displacement response spectra and displacement demand, recommended in Eurocode 8. The elastic response design spectrum from the standard pseudo-acceleration, versus natural period, Tn, format is converted to the Sa - Sd format. The elastic displacement response spectra and displacement demand are discussed with respect to the earthquake magnitude, the seismic source-to-site distance, seismic source mechanism, and the local geological site conditions. (author)

  19. Surface displacement studies using differential SAR interferometry: an overview

    Science.gov (United States)

    Gupta, Sonal; Sajith V., K.; Arora, Manoj K.; Sharma, Mukut L.

    2006-12-01

    The differential SAR interferometry (DInSAR) has been increasing used to monitor ground surface displacements, which may be caused by various natural disasters such as earthquakes, landslides, mining activities, avalanches etc. Conventionally, these displacements were being estimated through field measurements, which are time consuming, hazardous and with data collected over few point locations. Since all the development and rehabilitation works after a natural disaster strikes is carried out on regional basis, any information at spatial level is advantageous in planning, management and monitoring activities. In recent years, the application of Differential SAR interferometry is gaining momentum to estimate the surface displacements at millimeter level accuracy. The displacement maps produced via this technique provide information at spatial level in the region thereby assisting in judicious developmental and planning works in an efficient and cost-effective manner. The aim of this paper is provide an overview of the use of Differential SAR Interferometry (DinSAR) technology for the study of surface displacements. As a case study, land subsidence occurred due to coal mining in Jharia coal fields, Jharkhand, have been estimated through this technique. All the procedural steps in implementing the approach based on DinSAR have been explained in a simplified manner.

  20. Robust Tracking of Small Displacements With a Bayesian Estimator.

    Science.gov (United States)

    Dumont, Douglas M; Byram, Brett C

    2016-01-01

    Radiation-force-based elasticity imaging describes a group of techniques that use acoustic radiation force (ARF) to displace tissue to obtain qualitative or quantitative measurements of tissue properties. Because ARF-induced displacements are on the order of micrometers, tracking these displacements in vivo can be challenging. Previously, it has been shown that Bayesian-based estimation can overcome some of the limitations of a traditional displacement estimator such as normalized cross-correlation (NCC). In this work, we describe a Bayesian framework that combines a generalized Gaussian-Markov random field (GGMRF) prior with an automated method for selecting the prior's width. We then evaluate its performance in the context of tracking the micrometer-order displacements encountered in an ARF-based method such as ARF impulse (ARFI) imaging. The results show that bias, variance, and mean-square error (MSE) performance vary with prior shape and width, and that an almost one order-of-magnitude reduction in MSE can be achieved by the estimator at the automatically selected prior width. Lesion simulations show that the proposed estimator has a higher contrast-to-noise ratio but lower contrast than NCC, median-filtered NCC, and the previous Bayesian estimator, with a non-Gaussian prior shape having better lesion-edge resolution than a Gaussian prior. In vivo results from a cardiac, radio-frequency ablation ARFI imaging dataset show quantitative improvements in lesion contrast-to-noise ratio over NCC as well as the previous Bayesian estimator. PMID:26529761

  1. Simulation of miscible laboratory displacements by the total dispersion method

    International Nuclear Information System (INIS)

    The total dispersion method was developed to simulate first-contact miscible displacements performed in the laboratory. Simulations applying this method add sufficient dispersivity to the numerical dispersion inherent in finite differencing methods so the sum approximates the actual physical dispersion. This paper describes the application of this technique to model three floods taken from the literature and three displacements performed in a CT scanner. A key variable for modelling miscible displacements is dispersion. Numerical dispersion for both 1-point and 2-point upstream weighing was characterized as a function of grid block size and through put for an IMPES simulator. After quantifying numerical dispersion, three floods reported in the literature were simulated to confirm the total dispersion method. Recovery curves for two displacements dominated by viscous fingering that one exhibiting gravity override were modelled with good agreement. The authors' next objective was to determine if concentration profiles as well as recovery curves could be matched in a well characterized rock. First, longitudinal convective dispersion was measured for Bentheimer sandstone by a series of tritiated water displacements

  2. Laboratory imaging of stimulation fluid displacement from hydraulic fractures

    Energy Technology Data Exchange (ETDEWEB)

    Tidwell, V. [Sandia National Lab., Albuquerque, NM (United States); Parker, M. [SPE, Richardson, TX (United States)

    1996-11-01

    Laboratory experiments were conducted to physically investigate the processes governing stimulation fluid displacement from hydraulic fractures. Experiments were performed on two scales: meter-scale in a 1500 cm{sup 2} sand pack and core-scale in a 65 cm{sup 2} API linear conductivity cell. High-resolution light transmission imaging was employed at the meter-scale to visualize and quantify processes governing fluid displacement. For comparison, complimentary tests were performed using an API conductivity cell under ambient test conditions and at elevated closure stress. In these experiments viscous fingering and gravity drainage were identified as the dominant processes governing fluid displacement. Fluid viscosity was found to dictate the relative importance of the competing displacement processes and ultimately determine the residual liquid saturation of the sand pack. The process by which fluid displacement occurs was seen to effect the shape of both the gas and liquid phase relative permeability functions. Knowledge of such viscosity/relative permeability relationships may prove useful in bounding predictions of post-stimulation recovery of gels from the fracture pack.

  3. Linking pollination effectiveness and interspecific displacement success in bees.

    Science.gov (United States)

    Ali, M; Saeed, S; Sajjad, A; Akbar, A

    2015-04-01

    Pollen deposition, a surrogate for bee efficiency, becomes increasingly important during their interspecific interactions. We conducted field experiments on highly cross-pollinated melon (Cucumis melo) and watermelon (Citrullus lanatus) in order to understand how bee species with different pollination efficiencies displace each other from floral resources. We observed significant displacement of less abundant but more efficient bees by the more abundant but less efficient bees in both crops, which may lead to deficient pollination. We did not find significant relationship of the bee displacement success and body size or abundance. Apis florea (Fabricius) and Nomia sp.2 (Latreille) had significantly more winner events in melon, while the former also had significantly more winner events in watermelon. A. florea was the only bee species that foraged mostly within the 1-m(2) virtual area after their displacement, which may indicate its behavior of geitinogamous pollination. The two bee species, Ceratina sexmaculata (Smith) and Lasioglossum sp. (Curtis), were more sensitive to displacement as their proportion of leaving the 1-m(2) virtual area was higher. PMID:26013126

  4. Overhead Transmission Lines Deicing under Different Incentive Displacement

    Directory of Open Access Journals (Sweden)

    Qing He

    2014-01-01

    Full Text Available Overhead transmission line icing is one of the main factors affecting safety and reliability of power grid. This paper proposed an excitation deicing method of iced wire and theoretically revealed the ice removal mechanism under displacement excitation conditions, by taking the LGJ-70/10 glaze icing wire as the 3D model and analyzing and studying its dynamic response under the effect of displacement excitation. The simulation results show that the stress of wire icing area is enlarged with the increase of excitation displacement and frequency. Through the comparison of the compression strength experimental results on a series of different iced wires in low temperature environment, the authors found out that the stress generated from the wire icing area is greater than the crushing strength of the ice within the scope of the calculation parameters, which proved the validity and the feasibility of the method, and finally the suitable excitation displacement is determined. Following studies show that, as far as possible, it is necessary to reduce the incentive displacement and also to select the appropriate constraint length in order to avoid the line jumping that may be caused by large span ice shedding.

  5. Remodeling of a nontreated displaced parasymphyseal fracture of a child.

    Science.gov (United States)

    Kerem, Hakan; Usluer, Ayşen; Yoleri, Levent

    2011-07-01

    There have been considerable advances in the management of craniomaxillofacial injuries in children. Conservative approaches such as close observation, a liquid-to-soft diet, and analgesics can be used for the management of mandibular fractures without displacement and malocclusion. However, displaced fractures need to be an anatomic reduction and immobilization. The basic principle of displaced mandibular fractures in both children and adults is the stabilization of fracture fragments forming the pretraumatic contour and occlusion state until osteosynthesis occurs. The major differences of pediatric fractures from adults are the flexibility of bones and very rapid healing pattern. Therefore, reduction in pediatric age group must be accomplished earlier. This case was an 11-year-old boy presented with a severely displaced parasymphyseal mandibular fracture resulting from a fall. He was given a soft diet and analgesic, given anti-inflammatory treatment of edema, and scheduled for operation. Subsequently, it was surprisingly observed that there was a significant improvement in the fracture line on the 12th posttraumatic day. The comparison of maxillofacial computed tomographic scans of the first and 12th posttraumatic days revealed a noteworthy remodeling and a remarkable approximation of the fracture lines. It can be concluded that bone remodelization in the pediatric age groups is perfect and very rapid, even in severely displaced fractures. PMID:21772181

  6. An accurate elasto-plastic frictional tangential force displacement model for granular-flow simulations: Displacement-driven formulation

    Science.gov (United States)

    Zhang, Xiang; Vu-Quoc, Loc

    2007-07-01

    We present in this paper the displacement-driven version of a tangential force-displacement (TFD) model that accounts for both elastic and plastic deformations together with interfacial friction occurring in collisions of spherical particles. This elasto-plastic frictional TFD model, with its force-driven version presented in [L. Vu-Quoc, L. Lesburg, X. Zhang. An accurate tangential force-displacement model for granular-flow simulations: contacting spheres with plastic deformation, force-driven formulation, Journal of Computational Physics 196(1) (2004) 298-326], is consistent with the elasto-plastic frictional normal force-displacement (NFD) model presented in [L. Vu-Quoc, X. Zhang. An elasto-plastic contact force-displacement model in the normal direction: displacement-driven version, Proceedings of the Royal Society of London, Series A 455 (1991) 4013-4044]. Both the NFD model and the present TFD model are based on the concept of additive decomposition of the radius of contact area into an elastic part and a plastic part. The effect of permanent indentation after impact is represented by a correction to the radius of curvature. The effect of material softening due to plastic flow is represented by a correction to the elastic moduli. The proposed TFD model is accurate, and is validated against nonlinear finite element analyses involving plastic flows in both the loading and unloading conditions. The proposed consistent displacement-driven, elasto-plastic NFD and TFD models are designed for implementation in computer codes using the discrete-element method (DEM) for granular-flow simulations. The model is shown to be accurate and is validated against nonlinear elasto-plastic finite-element analysis.

  7. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  8. Atomic Energy Control Act

    International Nuclear Information System (INIS)

    This act provides for the establishment of the Atomic Energy Control Board. The board is responsible for the control and supervision of the development, application and use of atomic energy. The board is also considered necessary to enable Canada to participate effectively in measures of international control of atomic energy

  9. Note: Compact and light displacement sensor for a precision measurement system in large motion

    International Nuclear Information System (INIS)

    We developed a compact and light displacement sensor applicable to systems that require wide range motions of its sensing device. The proposed sensor utilized the optical pickup unit of the optical disk drive, which has been used applied to atomic force microscopy (AFM) because of its compactness and lightness as well as its high performance. We modified the structure of optical pickup unit and made the compact sensor driver attachable to a probe head of AFM to make large rotation. The feasibilities of the developed sensor for a general probe-moving measurement device and for probe-rotating AFM were verified. Moreover, a simple and precise measurement of alignment between centers of rotator and probe tip in probe-rotation AFM was experimentally demonstrated using the developed sensor

  10. Weak measurement from the electron displacement current: new path for applications

    Science.gov (United States)

    Marian, D.; Colomés, E.; Zanghì, N.; Oriols, X.

    2015-10-01

    The interest on weak measurements is rapidly growing during the last years as a unique tool to better understand and predict new quantum phenomena. Up to now many theoretical and experimental weak-measurement techniques deal with (relativistic) photons or cold atoms, but there is much less investigation on (non-relativistic) electrons in up-to-date electronics technologies. We propose a way to perform weak measurements in nanoelectronic devices through the measurement of the total current (particle plus displacement component) in such devices. We study the interaction between an electron in the active region of a electron device with a metal surface working as a sensing electrode by means of the (Bohmian) conditional wave function. We perform numerical (Monte Carlo) simulations to reconstruct the Bohmian trajectories in the iconic double slit experiment. This work opens new paths for understanding the quantum properties of an electronic system as well as for exploring new quantum engineering applications in solid state physics.

  11. Note: Compact and light displacement sensor for a precision measurement system in large motion

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Heon, E-mail: shlee@andong.ac.kr [Department of Mechanical Design Engineering, Andong National University, Andong, Kyungbuk 760-749 (Korea, Republic of)

    2015-08-15

    We developed a compact and light displacement sensor applicable to systems that require wide range motions of its sensing device. The proposed sensor utilized the optical pickup unit of the optical disk drive, which has been used applied to atomic force microscopy (AFM) because of its compactness and lightness as well as its high performance. We modified the structure of optical pickup unit and made the compact sensor driver attachable to a probe head of AFM to make large rotation. The feasibilities of the developed sensor for a general probe-moving measurement device and for probe-rotating AFM were verified. Moreover, a simple and precise measurement of alignment between centers of rotator and probe tip in probe-rotation AFM was experimentally demonstrated using the developed sensor.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wampler, William R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Myers, Samuel M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    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.

  13. Intercomparison of predicted displacement rates based on neutron spectrum adjustments (REAL-80 exercise)

    Energy Technology Data Exchange (ETDEWEB)

    Zijp, W.L.; Nolthenius, H.J.; Szondi, E.J.; Verhaag, G.C.; Zsolnay, E.M.

    1984-11-01

    The aim of the interlaboratory REAL-80 exercise, organized by the International Atomic Energy Agency, was to determine the state of the art in 1981 of the capabilities of laboratories to adjust neutron spectrum information on the basis of a set of experimental activation rates, and to subsequently predict the number of displacements in steel, together with its uncertainty. The input information distributed to participating laboratories comprised values, variances, and covariances for a set of input fluence rates, for a set of activation and damage cross-section data, and for a set of experimentally measured reaction rates. The exercise dealt with two clearly different spectra: the thermal Oak Ridge Research Reactor (ORR) spectrum and the fast YAYOI spectrum. Out of 30 laboratories asked to participate, 13 laboratories contributed 33 solutions for ORR and 35 solutions for YAYOI. The spectral shapes of the solution spectra showed considerable spread, both for the ORR and YAYOI spectra. When the series of predicted activation rates in nickel and the predicted displacement rates in steel derived for all solutions is considered, one cannot observe significant differences due to the adjustment algorithm used. The largest deviations seem to be due to effects related to group structure and/or changes in the input data. When comparing the predicted activation rate in nickel with its available measured value, the authors observe that the predicted value (averaged over all solutions) is lower than the measured value.

  14. Bainite transformation as a displacive decomposition of austenite. Sendan gata hentai to shite toraeta bainite hentai

    Energy Technology Data Exchange (ETDEWEB)

    Omori, Y. (Sumitomo Metal Industries, Ltd., Osaka (Japan))

    1990-07-20

    In the typical textures of hypo-eutictoid steel (hyper-eutictoid steel), there are pro-eutictoid ferrite and pearlite which are generated by the diffusion mechanism and martensite ({alpha}') which is generated by non-diffusion transformation. However, when austenite ({gamma}) is decomposed in the temperature range between about 900K and the Ms point at which martensite transformation starts, bainite is generated. Concerning the bainite generation mechanism, the views are separated into the standpoint of considering that transformation of substitutional atoms progresses in a manner of non-diffusion (the displacive transformation group) and the standpoint that such transformation is basically diffusion transformation only with shorter diffusion distance (the diffusion transformation group). In this article, the concept that the above transformation is displacive transformation is explained. In other words, after stating in detail on bainite transformation behavior, crystals of bainite transformation, and so forth, it discusses on what is bainite. Finally in this article, it is pointed out that the bainite texture has the nature that it cannot be decided simply either the diffusion transformation texture or the non-diffusion transformation texture. 95 refs., 11 figs.

  15. Intercomparison of predicted displacement rates based on neutron spectrum adjustments (REAL-80 exercise)

    International Nuclear Information System (INIS)

    The aim of the interlaboratory REAL-80 exercise, organized by the International Atomic Energy Agency, was to determine the state of the art in 1981 of the capabilities of laboratories to adjust neutron spectrum information on the basis of a set of experimental activation rates, and to subsequently predict the number of displacements in steel, together with its uncertainty. The input information distributed to participating laboratories comprised values, variances, and covariances for a set of input fluence rates, for a set of activation and damage cross-section data, and for a set of experimentally measured reaction rates. The exercise dealt with two clearly different spectra: the thermal Oak Ridge Research Reactor (ORR) spectrum and the fast YAYOI spectrum. Out of 30 laboratories asked to participate, 13 laboratories contributed 33 solutions for ORR and 35 solutions for YAYOI. The spectral shapes of the solution spectra showed considerable spread, both for the ORR and YAYOI spectra. When the series of predicted activation rates in nickel and the predicted displacement rates in steel derived for all solutions is considered, one cannot observe significant differences due to the adjustment algorithm used. The largest deviations seem to be due to effects related to group structure and/or changes in the input data. When comparing the predicted activation rate in nickel with its available measured value, the authors observe that the predicted value (averaged over all solutions) is lower than the measured value

  16. Supervised Learning in Adaptive DNA Strand Displacement Networks.

    Science.gov (United States)

    Lakin, Matthew R; Stefanovic, Darko

    2016-08-19

    The development of engineered biochemical circuits that exhibit adaptive behavior is a key goal of synthetic biology and molecular computing. Such circuits could be used for long-term monitoring and control of biochemical systems, for instance, to prevent disease or to enable the development of artificial life. In this article, we present a framework for developing adaptive molecular circuits using buffered DNA strand displacement networks, which extend existing DNA strand displacement circuit architectures to enable straightforward storage and modification of behavioral parameters. As a proof of concept, we use this framework to design and simulate a DNA circuit for supervised learning of a class of linear functions by stochastic gradient descent. This work highlights the potential of buffered DNA strand displacement as a powerful circuit architecture for implementing adaptive molecular systems. PMID:27111037

  17. Displacement of carbon-14 labelled amino acids from leaves

    International Nuclear Information System (INIS)

    The displacement of amino acids from nature leaves was investigated. The amino acids (Ala, Asn, Asp, Glu, Gln, Val, Leu, Lys, Ser, Pro) were applied on the leaves in L-form, uniformly labelled with 14C, and the type and direction of displacement have been observed. Most of the studies have been carried out on bush beans aged 3 to 4 weeks. The experiments were carried out in climatic chambers; in one case, barley plants just reaching maturity were used. In order to find out whether the applied amino acids were also displaced in their original form, freeze-dried plants were extracted and the 14C activity of the various fraction was determined. The radioactivity of some free amino acids was determined after two-dimensional separation by thin film chromatography. (orig./HK)

  18. Beamforming Scheme for 2D Displacement Estimation in Ultrasound Imaging

    Directory of Open Access Journals (Sweden)

    Philippe Delachartre

    2005-05-01

    Full Text Available We propose a beamforming scheme for ultrasound imaging leading to the generation of two sets of images, one with oscillations only in the axial direction and one with oscillations only in the lateral direction. Applied to tissue elasticity imaging, this leads to the development of a specific displacement estimation technique that is capable of accurate estimation of two components of the displacement. The mean standard deviation for the axial displacement estimates is 0.0219 times the wavelength of the axial oscillations λz, and for the lateral estimates, it is equal to 0.0164 times the wavelength of the lateral oscillations λx. The method is presented and its feasibility is clearly established by a simulation work.

  19. Molecular basis for DNA strand displacement by NHEJ repair polymerases.

    Science.gov (United States)

    Bartlett, Edward J; Brissett, Nigel C; Plocinski, Przemyslaw; Carlberg, Tom; Doherty, Aidan J

    2016-03-18

    The non-homologous end-joining (NHEJ) pathway repairs DNA double-strand breaks (DSBs) in all domains of life. Archaea and bacteria utilize a conserved set of multifunctional proteins in a pathway termed Archaeo-Prokaryotic (AP) NHEJ that facilitates DSB repair. Archaeal NHEJ polymerases (Pol) are capable of strand displacement synthesis, whilst filling DNA gaps or partially annealed DNA ends, which can give rise to unligatable intermediates. However, an associated NHEJ phosphoesterase (PE) resects these products to ensure that efficient ligation occurs. Here, we describe the crystal structures of these archaeal (Methanocella paludicola) NHEJ nuclease and polymerase enzymes, demonstrating their strict structural conservation with their bacterial NHEJ counterparts. Structural analysis, in conjunction with biochemical studies, has uncovered the molecular basis for DNA strand displacement synthesis in AP-NHEJ, revealing the mechanisms that enable Pol and PE to displace annealed bases to facilitate their respective roles in DSB repair. PMID:26405198

  20. Polymeric nanospheres as a displacement fluid in enhanced oil recovery

    Science.gov (United States)

    Hendraningrat, Luky; Zhang, Julien

    2015-11-01

    This paper presents the investigation of using nanoscale polyacrylamide-based spheres (nanospheres) as a displacement fluid in enhanced oil recovery (EOR). Coreflood experiments were conducted to evaluate the impact of nanospheres and its concentration dispersed in model formation water on oil recovery during a tertiary oil recovery process. The coreflood results showed that nanospheres can enhance residual oil recovery in the sandstone rock samples and its concentration showed a significant impact into incremental oil. By evaluating the contact angle, it was observed that wettability alteration also might be involved in the possible oil displacement mechanism in this process together with fluid behavior and permeability to water that might divert injected fluid into unswept oil areas and enhance the residual oil recovery. These investigations promote nanospheres aqueous disperse solution as a potential displacement fluid in EOR.

  1. Geometric interpretation of density displacements and charge sensitivities

    Indian Academy of Sciences (India)

    Roman F Nalewajski

    2005-09-01

    The ``geometric” interpretation of the electronic density displacements in the Hilbert space is given and the associated projection-operator partitioning of the hardness and softness operators (kernels) is developed. The eigenvectors |á 〉 = \\{| 〉 \\} of the hardness operator define the complete (identity) projector $\\hat{P}$ = | 〉 〈 = 1 for general density displacements, including the charge-transfer (CT) component, while the eigenvectors | i 〉 = { | 〉} of the linear response operator determine the polarizational -projector, $\\hat{P}$ = | 〉 〈 |. Their difference thus defines the complementary CT-projector: $\\hat{P}$ = 1 - $\\hat{P}$. The complete vector space for density displacements can be also spanned by supplementing the -modes with the homogeneous CT-mode. These subspaces separate the integral (normalization) and local aspects of density shifts in molecular systems.

  2. System design of welding dynamic displacement measurement using laser ESPI

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the advantages of electronic speckle pattern interferometry(ESPI), such as non-contact, high precision, strong parasitic light resistance, and full-field measurement, a system for measuring welding dynamic displacement fields using ESPI was designed. The system consists of a 70mW He-Ne laser source, an optical path system, a computer-assisted frame grabber and a processing system. By measuring dynamic displacement fields on one LY2 aluminum alloy plate during an argon arc point welding, it can be proved that using ESPI to measure welding dynamic displacement fields is fully feasible, and this method can offer a solid experimental base for the structure mechanics.

  3. Novel pressure and displacement sensors based on carbon nanotubes

    International Nuclear Information System (INIS)

    We report newly designed pressure and displacement capacitive sensors based on a flexible paper–CNT structure. The carbon nanotube (CNT) powder was deposited on a thin paper substrate and was pressed at an elevated temperature. The sheet resistance of the paper–CNT films was in the range of 2–4 kΩ/cm2. The paper–CNT films were used to fabricate pressure and displacement sensors. The sensitivities of the pressure and the displacement sensors were found to be 17.3 pF·m2/kN and 0.93 10−3 pF/μm, respectively. The experimental results were compared with the simulated data and they found good agreement with each other. (paper)

  4. Modeling Non-aqueous Phase Liquid Displacement Process

    Institute of Scientific and Technical Information of China (English)

    Yang Zhenqing; Shao Changjin; Zhou Guanggang; Qiu Chao

    2007-01-01

    A pore-network model physically based on pore level multiphase flow was used to study the water-non-aqueous phase liquid (NAPL) displacement process, especially the effects of wettability, water-NAPL interfacial tension, the fraction of NAPL-wet pores, and initial water saturation on the displacement. The computed data show that with the wettability of the mineral surfaces changing from strongly water-wet to NAPL-wet, capillary pressure and the NAPL relative permeability gradually decrease, while water-NAPL interfacial tension has little effect on water relative permeability, but initial water saturation has a strong effect on water and NAPL relative permeabilities. The analytical results may help to understand the micro-structure displacement process of non-aqueous phase liquid and to provide the theoretical basis for controlling NAPL migration.

  5. Differential reflective fiber-optic angular displacement sensor

    Science.gov (United States)

    Shan, Mingguang; Min, Rui; Zhong, Zhi; Wang, Ying; Zhang, Yabin

    2015-05-01

    Using the characteristic that the distance apart between the emitting fiber and receiving fiber only shifts the angular-power curve, a differential reflective fiber-optic sensor for angular displacement measurement is presented through subtraction of two power signals from two receiving fibers placed on both sides of one emitting fiber. A theoretical model is established to characterize the performance of the differential reflective fiber-optic angular displacement sensor. The measurements made indicate that the general behavior of the experimental results agrees with that of the theoretical results, and the sensor can improve sensitivity by about 120%, resulting in the significant improvement of anti-interference capability, which will be more suitable for high accuracy bipolar absolute angular displacement measurement. Design guidelines are also suggested to achieve desired sensor performances.

  6. Crustal displacements in Greenland caused by ice mass variability

    DEFF Research Database (Denmark)

    Nielsen, Karina

    The climate of the Earth is changing. A consequence of this is observed at the polar regions such as Greenland, where the ice sheet is melting with an increasing rate. The unloading of ice causes the Earth to respond elastically in terms of uplift and an outward horizontal deformation of the crust...... the state of the ice sheet. However, the Earth is also adjusting viscoelastically to variations in the late Pleistocene ice sheets i.e. glacial isostatic adjustment (GIA). Observed rates of crustal displacement therefor contain signals from both past and present ice mass variations. Hence, to...... interpret the observed rates a separation of theses signals are needed. In this thesis, observed rates of crustal displacement are combined with modeled elastic rates to obtain constraints on the vertical displacement rate related to GIA. Observed rates are furthermore used to assess the local mass balance...

  7. Displaced vertex searches for sterile neutrinos at future lepton colliders

    CERN Document Server

    Antusch, Stefan; Fischer, Oliver

    2016-01-01

    We investigate the sensitivity of future lepton colliders to displaced vertices from the decays of long-lived heavy (almost sterile) neutrinos with electroweak scale masses and detectable time of flight. As future lepton colliders we consider the FCC-ee, the CEPC, and the ILC, searching at the Z-pole and at the center-of-mass energies of 240, 350 and 500 GeV. For a realistic discussion of the detector response to the displaced vertex signal and the Standard Model background we consider the ILC's Silicon Detector (SiD) as benchmark for the future lepton collider detectors. We find that displaced vertices constitute a powerful search channel for sterile neutrinos, sensitive to squared active-sterile mixing angles as small as $10^{-11}$.

  8. In-plane displacement measurement using optical vortex phase shifting.

    Science.gov (United States)

    Sun, Haibin; Wang, Xinghai; Sun, Ping

    2016-07-20

    In this paper, we propose a new method for in-plane displacement measurement by application of phase shifting based on an optical vortex. The phase shifts are obtained by displaying computer-generated fork holograms on the screen of a liquid-crystal spatial light modulator (LC-SLM). Furthermore, the vortex beam that is generated by the LC-SLM can be used as a reference light in the experiment. Eight speckle patterns with phase-shift increments of 0, π/2, π, and 3π/2 were captured by a CCD camera before and after the deformation. The displacement of the deformed object was obtained by unwrapping. Experimental results demonstrated the efficacy of the proposed method for in-plane displacement measurement. PMID:27463914

  9. On the analysis of competitive displacement in dengue disease transmission

    Science.gov (United States)

    Wijaya, Karunia P.; Nuraini, Nuning; Soewono, Edy; Handayani, Dewi

    2014-03-01

    We study a host-vector model involving the interplay of competitive displacement mechanism in a specific DENV serotype, both in human blood and mosquito blood. Using phylogenetic analysis, world virologists investigate the severe manifestations of dengue fever caused by the displacements within weakly virulent pathogens (native strains) by more virulent pathogens (invasive strains) in one serotype. We construct SIR model for human and SI model for mosquito to explore the key determinants of those displacements. Analysis of nonnegativity and boundedness of the solution as well as the basic reproduction number (R0) are taken into account for verifying the model into biological meaningfulness. To generate predictions of the outcomes of control strategies, we derive an optimal control model which involves two control apparatus: fluid infusion (for human) and fumigation (for vector). Numerical results show the dynamics of host-vector in an observation period, both under control and without control.

  10. Numerical Modelling of the Mining Induced Horizontal Displacement

    Science.gov (United States)

    Tajduś, Krzysztof

    2015-12-01

    The paper presents results of numerical calculations and modeling of mining-induced surface deformation based on Finite Element Method (FEM). Applying the numerical method discussed to calculations allows us to assume a larger number of factors, such as rock mass structure, fracture network, rock properties, etc., which essentially affect the results obtained. On the basis of an elastic transversely isotropic model, an analysis of horizontal displacement distribution and surface subsidence was carried out for two sample regions of mines. The results of numerical calculations were later compared with the measured values. Such an analysis proved that the applied numerical model properly described distribution and values of subsidence and slope of subsidence trough, though there were serious differences in the values of calculated horizontal displacement, especially in areas of far influence range. In order to improve the matching, the influence of boundary conditions of the model on the value of calculated horizontal displacement was analyzed. The results are presented in graphs.

  11. Time varying behavior of the loudspeaker suspension: Displacement level dependency

    DEFF Research Database (Denmark)

    Agerkvist, Finn T.; Pedersen, Bo Rohde

    2009-01-01

    how much the suspension has been stretched, i.e. the maximum displacement, is investigated. For this purpose the changes in compliance are measured when exposing the speaker to different levels and types of electrical excitation signals, as well as mechanical excitation only. For sinusoidal excitation......The compliance of the loudspeaker suspension is known to depend on the recent excitation level history. Previous investigations have shown that the electrical power as well as displacement and velocity plays a role. In this paper the hypothesis that the changes in compliance are caused mainly by...... the change in compliance is shown to depend primarily on maximum displacement. But for square pulse excitation the duration of the excitation also plays an important role...

  12. Treatment of displaced mandibular condylar fracture with botulinum toxin A.

    Science.gov (United States)

    Akbay, Ercan; Cevik, Cengiz; Damlar, Ibrahim; Altan, Ahmet

    2014-04-01

    The aim of this case report is to discuss the effect on condylar reduction of botulinum toxin A treatment used in a child with displaced fracture at condylar neck of mandible. A 3-years old boy was admitted to our clinic for incomplete fracture of mandibular symphysis and displaced condylar fracture at the left side. An asymmetrical occlusal splint with intermaxillary fixation was used instead of open reduction and internal fixation because of incomplete fracture of symphysis and possible complications of condyle surgery. However, it was observed that condylar angulation persisted despite this procedure. Thus, botulinum toxin A was administered to masseter, temporalis and pterygoideus medialis muscles. At the end of first month, it was seen that mandibular condyle was almost completely recovered and that fusion was achieved. In conclusion, Botulinum A toxin injection aiming the suppression of masticatory muscle strength facilitates the reduction in the conservative management of displaced condyle in pediatric patients. PMID:24156980

  13. Measurement of the gold–gold bond rupture force at 4 K in a single-atom chain using photon-momentum-based force calibration

    International Nuclear Information System (INIS)

    We present instrumentation and methodology for simultaneously measuring force and displacement at the atomic scale at 4 K. The technique, which uses a macroscopic cantilever as a force sensor and high-resolution, high-stability fiber-optic interferometers for displacement measurement, is particularly well-suited to making accurate, traceable measurements of force and displacement in nanometer- and atomic-scale mechanical deformation experiments. The technique emphasizes accurate co-location of force and displacement measurement and measures cantilever stiffness at the contact point in situ at 4 K using photon momentum. We present preliminary results of measurements made of the force required to rupture a single atomic bond in a gold single-atom chain formed between a gold flat and a gold tip. Finally, we discuss the possible use of the gold–gold bond rupture force as an intrinsic force calibration value for forces near 1 nN. (paper)

  14. Single atom electrochemical and atomic analytics

    Science.gov (United States)

    Vasudevan, Rama

    In the past decade, advances in electron and scanning-probe based microscopies have led to a wealth of imaging and spectroscopic data with atomic resolution, yielding substantial insight into local physics and chemistry in a diverse range of systems such as oxide catalysts, multiferroics, manganites, and 2D materials. However, typical analysis of atomically resolved images is limited, despite the fact that image intensities and distortions of the atoms from their idealized positions contain unique information on the physical and chemical properties inherent to the system. Here, we present approaches to data mine atomically resolved images in oxides, specifically in the hole-doped manganite La5/8Ca3/8MnO3, on epitaxial films studied by in-situ scanning tunnelling microscopy (STM). Through application of bias to the STM tip, atomic-scale electrochemistry is demonstrated on the manganite surface. STM images are then further analyzed through a suite of algorithms including 2D autocorrelations, sliding window Fourier transforms, and others, and can be combined with basic thermodynamic modelling to reveal relevant physical and chemical descriptors including segregation energies, existence and strength of atomic-scale diffusion barriers, surface energies and sub-surface chemical species identification. These approaches promise to provide tremendous insights from atomically resolved functional imaging, can provide relevant thermodynamic parameters, and auger well for use with first-principles calculations to yield quantitative atomic-level chemical identification and structure-property relations. This research was sponsored by the Division of Materials Sciences and Engineering, BES, DOE. Research was conducted at the Center for Nanophase Materials Sciences, which also provided support and is a DOE Office of Science User Facility.

  15. Atomic swelling upon compression

    CERN Document Server

    Dolmatov, V K

    2012-01-01

    The hydrogen atom under the pressure of a spherical penetrable confinement potential of a decreasing radius $r_{0}$ is explored, as a case study. A novel counter-intuitive effect of atomic swelling rather than shrinking with decreasing $r_{0}$ is unraveled, when $r_{0}$ reaches, and remains smaller than, a certain critical value. Upon swelling, the size of the atom is shown to increase by an order of magnitude, or more, compared to the size of the free atom. Examples of changes of photoabsorption properties of confined hydrogen atom upon its swelling are uncovered and demonstrated.

  16. Spontaneous spherical symmetry breaking in atomic confinement

    CERN Document Server

    Sveshnikov, K

    2016-01-01

    The effect of spontaneous breaking of initial SO(3) symmetry is shown to be possible for an H-like atom in the ground state, when it is confined in a spherical box under general boundary conditions of "not going out" through the box surface (i.e. third kind or Robin's ones), for a wide range of physically reasonable values of system parameters. The reason is that such boundary conditions could yield a large magnitude of electronic wavefunction in some sector of the box boundary, what in turn promotes atomic displacement from the box center towards this part of the boundary, and so the underlying SO(3) symmetry spontaneously breaks. The emerging Goldstone modes, coinciding with rotations around the box center, restore the symmetry by spreading the atom over a spherical shell localized at some distances from the box center. Atomic confinement inside the cavity proceeds dynamically -- due to the boundary condition the deformation of electronic wavefunction near the boundary works as a spring, that returns the at...

  17. The Effect of Job Displacement on Couples? Fertility Decisions

    OpenAIRE

    Huttunen, Kristiina; Kellokumpu, Jenni

    2012-01-01

    This paper analyzes the effects of job displacement on fertility using Finnish longitudinal employer-employee data (FLEED) matched to birth records. We distinguish between male and female job losses. We focus on couples where one spouse has lost his/her job due to a plant closure or mass layoff and follow them for several years both before and following the job loss. As a comparison group we use similar couples that were not affected by job displacement. In order to examine the possible chann...

  18. A reduced model for fingering instability in miscible displacement

    International Nuclear Information System (INIS)

    The classical problem of fingering instability in miscible displacement is revisited. The finger-forming dynamics is considered as a multiple-scale process involving a thin inter-diffusion layer and large-scale background flow affected by the viscosity and/or density stratification. Upon an appropriate separation of 'fast' and 'slow' variables one ends up with a reduced model dealing directly with the evolving displacement front. As an illustration, the new model is applied for description of fingering in a source-supported flow and in a flow within a vertical channel

  19. A Miniature Large Displacement Linear Nanopositioning Piezoelectric Actuator

    Institute of Scientific and Technical Information of China (English)

    Lu Qiuhong(卢秋红); Yan Guozheng

    2004-01-01

    A miniature linear piezoelectric actuator which moves based on inertia friction theory is described in this paper. The authors discuss its driving principle, dynamic model and experimental results.The piezoelectric actuator includes two piezoelectric elements.Through the sequentially deformations of the two piezo elements, the moving mass slides a miniature displacement. Many strokes will be added to be a large displacement.This type of piezoactuator has advantages in its dimension and motion type,so it can be miniaturized to do micro manipulation or micropositioning in microspace.

  20. Displacement estimates of pipe elbows prior to plastic collapse loads

    International Nuclear Information System (INIS)

    The classic limit analysis gives only information about the limit load (or limit multiplier) and the plastic collapse mechanism. Based in the Zarks's method and using the finite element method and mathematical programming it is possible to obtain not only the limit load but also the estimated elastoplastic displacement. This circumstance is very useful because construction codes require limitation of the realistic elastoplastic displacements. The present work is dealing with such calculations and the structure of pipes and elbows are considered. The comparison with the results obtained by classical limit analysis is illustrated by some examples. (author). 8 refs., 3 figs

  1. Absolute Measurement of Quantum-Limited Interferometric Displacements

    CERN Document Server

    Thiel, Valérian; Treps, Nicolas; Roslund, Jonathan

    2016-01-01

    A methodology is introduced that enables an absolute, quantum-limited measurement of sub-wavelength interferometric displacements. The technique utilizes a high-frequency optical path modulation within an interferometer operated in a homodyne configuration. All of the information necessary to fully characterize the resultant path displacement is contained within the relative strengths of the various harmonics of the phase modulation. The method, which is straightforward and readily implementable, allows a direct measurement of the theoretical Cram\\'er-Rao limit of detection without any assumptions on the nature of the light source.

  2. Coulomb displacement energies in nuclei: a new approach

    International Nuclear Information System (INIS)

    The neutron core polarization gives rise to an important correction to the direct Coulomb contribution when one calculates the Coulomb displacement energies. In the Hartree-Fock model it is shown that this correction is about 2% to 4.5% in medium and heavy nuclei. The core polarization as well as other higher order effects can be included by using a selfconsistent description of the analog state in a complete proton particle-neutron hole space. The Coulomb displacement energies in 48Ca, 88Sr and 208Pb have been calculated using Skyrme interactions SIII and SIV. A good agreement with experiment is obtained

  3. Topology synthesis of large-displacement compliant mechanisms

    DEFF Research Database (Denmark)

    Pedersen, Claus B. Wittendorf; Buhl, Thomas; Sigmund, Ole

    2001-01-01

    This paper describes the use of topology optimization as a synthesis tool for the design of large-displacement compliant mechanisms. An objective function for the synthesis of large-displacement mechanisms is proposed together with a formulation for synthesis of path-generating compliant mechanisms....... The responses of the compliant mechanisms are modelled using a total Lagrangian finite element formulation, the sensitivity analysis is performed using the adjoint method and the optimization problem is solved using the method of moving asymptotes. Procedures to circumvent some numerical problems are...

  4. Current Density and Plasma Displacement Near Perturbed Rational Surface

    International Nuclear Information System (INIS)

    The current density in the vicinity of a rational surface of a force-free magnetic field subjected to an ideal perturbation is shown to be the sum of both a smooth and a delta-function distribution, which give comparable currents. The maximum perturbation to the smooth current density is comparable to a typical equilibrium current density and the width of the layer in which the current flows is shown to be proportional to the perturbation amplitude. In the standard linearized theory, the plasma displacement has an unphysical jump across the rational surface, but the full theory gives a continuous displacement.

  5. Spatial distribution of strength and displacement demands for Romanian earthquakes

    International Nuclear Information System (INIS)

    The paper presents part of the results of an extensive study performed on strong earthquakes (moment magnitude larger than 6.0) recorded in Romania in the last 30 years. The study involved the mapping of peak ground motion ordinates as well as of linear and nonlinear spectral ordinates for four seismic events recorded in 1986, 1990 and 2004. A distinct part of the study focused on the mapping and analysis of spectral ordinates for linear and nonlinear acceleration and displacement. Based on the maps, generated for different values of period and ductility, conclusions were drawn on the spatial distribution of strength and displacement demands for the concerned seismic event. (authors)

  6. Traumatisk diafragmaruptur med displacering af leveren til thorax

    DEFF Research Database (Denmark)

    Hornstrup, L.; Burcharth, F.

    2008-01-01

    We report a case of a traumatic diaphragmatic rupture with the liver displaced to the right hemithorax. MR diagnosed the rupture and the displacement of the liver. The patient was operated on and the total right diaphragmatic rupture was reconstructed by suturing. Traumatic diaphragmatic rupture...... may occur after high velocity accidents, especially after lateral collisions in traffic. Diagnosis may be delayed as a result of variable clinical and radiological signs. It is important to discover the rupture in the acute phase. Treatment is operative Udgivelsesdato: 2008/4/28...

  7. Application of miscible displacement for Field MTX low permeability formations

    International Nuclear Information System (INIS)

    Miscible displacement is a very effective method of recovery efficiency improvement. It is widely used in the world, but this technology is not widely used in Russia. For this reason, it is necessary to study global experience and physical aspects of this EOR method. The most important factors and limitations of miscible displacement application from the geological point of view (heterogeneity) and from the physical point of view (properties of injected fluids and reservoir fluids) should be determined. The results of this analysis should be tested on the low permeability reservoir of field MTX with analytical, proxy calculation and simulation methods

  8. (3,1) Drive PVDF acoustic displacement sensor

    Energy Technology Data Exchange (ETDEWEB)

    Caspall, J.J.; Caille, G.W. [Georgia Tech Research Institute, Undersea Research Program Office, Georgia Institute of Technology, Atlanta, Georgia 30332-0810 (United States); Jarzynski, J.; McCall, G.S. II [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States)

    1996-04-01

    A (3,1) drive piezofilm vibration sensor is introduced. Operated above the lumped element resonance frequency of 600 Hz, the sensor delivers a voltage signal proportional to displacement over the frequency range of 2 kHz to 8 kHz. It is anticipated that the sensor response is flat above 8 kHz, but calibration has not been performed at higher frequencies. The sensor is very sensitive, detecting acoustic displacements as small as 10{sup {minus}5} nm. Because of its simple design the sensor is robust and easy to assemble. {copyright} {ital 1996 American Institute of Physics.}

  9. SPS data on tunnel displacements and the ATL law

    International Nuclear Information System (INIS)

    In this article we analyze data from long-term measurements of quadrupole displacements in the Super Proton Synchrotron ring at CERN. The variance of displacement can be approximated by ATL law with coefficient A = (0.1--0.4) * 10-4 μm2/s/m, with T the time interval between measurements and L the distance between two points of the tunnel. The shape of the distribution function is found to be close to Gaussian. The results of the analysis are compared with other data on slow ground motion

  10. Multiple-aperture speckle method applied to local displacement measurements

    Science.gov (United States)

    Ángel, Luciano; Tebaldi, Myrian; Bolognini, Néstor

    2007-06-01

    The goal of this work is to analyze the measurement capability of the modified speckle photography technique that uses different multiple aperture pupils in a multiple exposure scheme. In particular, the rotation case is considered. A point-wise analysis procedure is utilized to obtain the fringes required to access to the local displacement measurements. The proposed arrangement allows simultaneous displaying in the Fourier plane several fringes system each one associated with different rotations. We experimentally verified that the local displacement measurements can be determined with a high precision and accuracy.

  11. Study of temperature dependent atomic correlations in MgB$_{2}$

    OpenAIRE

    Campi, G.; Cappelluti, E.; Proffen, Th.; Qiu, X.; Bozin, E. S.; Billinge, S. J. L.; Agrestini, S.; Saini, N.L.; Bianconi, A.

    2006-01-01

    We have studied the evolution with temperature of the local as well as the average crystal structure of MgB$_2$ using the real-space atomic pair distribution function (PDF) measured by high resolution neutron powder diffraction. We have investigated the correlations of the B-B and B-Mg nearest neighbor pair motion by comparing, in the wide temperature range from T=10 K up to T=600 K, the mean-square displacements (MSD) of single atoms with the mean-square relative displacements (MSRD) obtaine...

  12. Single Atom Plasmonic Switch

    CERN Document Server

    Emboras, Alexandros; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individual or at most - a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ration of 10 dB and operation at room temperature with femtojoule (fJ) power consumption for a single switch operation. This demonstration of a CMOS compatible, integrated quantum device allowing to control photons at the single-atom level opens intriguing perspectives for a fully i...

  13. Excited atoms. Vozbuzhdennye atomy

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, B.M.

    1982-01-01

    An examination is made of the properties of excited atoms and molecules, the processes of their formation in a gas and plasma, and the diffusion of excited atoms in a gas. A presentation is made of the processes in which excited and metastable atoms and molecules in a gas are destroyed upon collision with electrons, atoms, and molecules. A study is made of the relaxation of excited states during collisions - excitation transfer, depolarization, transitions between fine structure states, etc. Information is given on ionization that includes the participation of excited atoms - the Penning process, associative ionization. An examination is made of highly excited states of atoms and the processes that take place during their participation. The book is intended for personnel in the area of physics and chemistry of plasma, atomic and molecular physics, chemical physics as well as in allied areas of physics. 1280 references, 52 figures, 76 tables.

  14. Interferometry with atoms

    International Nuclear Information System (INIS)

    Optics and interferometry with matter waves is the art of coherently manipulating the translational motion of particles like neutrons, atoms and molecules. Coherent atom optics is an extension of techniques that were developed for manipulating internal quantum states. Applying these ideas to translational motion required the development of techniques to localize atoms and transfer population coherently between distant localities. In this view position and momentum are (continuous) quantum mechanical degrees of freedom analogous to discrete internal quantum states. In our contribution we start with an introduction into matter wave optics in sect. 1, discuss coherent atom optics and atom interferometry techniques for molecular beams in sect. 2 and for trapped atoms in sect. 3. In sect. 4 we then describe tools and experiments that allow to probe the evolution of quantum states of many-body systems by atom interference.

  15. Atomic structure of non-stoichiometric transition metal carbides

    International Nuclear Information System (INIS)

    Different kinds of experimental studies of the atomic arrangement in non-stoichiometric transition metal carbides are proposed: the ordering of carbon vacancies and the atomic static displacements are the main subjects studied. Powder neutron diffraction on TiCsub(1-x) allowed us to determine the order-disorder transition critical temperature -Tsub(c) approximately 7700C- in the TiCsub(0.52-0.67) range, and to analyze at 300 K the crystal structure of long-range ordered samples. A neutron diffuse scattering quantitative study at 300 K of short-range order in TiCsub(0.76), TiCsub(0.79) and NbCsub(0.73) single crystals is presented: as in Ti2Csub(1+x) and Nb6C5 superstructures, vacancies avoid to be on each side of a metal atom. Besides, the mean-square carbon atom displacements from their sites are small, whereas metal atoms move radially about 0.03 A away from vacancies. These results are in qualitative agreement with EXAFS measurements at titanium-K edge of TiCsub(1-x). An interpretation of ordering in term of short-range interaction pair potentials between vacancies is proposed

  16. Displacement cascades produced in Cu3Au by 1.8 GeV Ar ion irradiation

    International Nuclear Information System (INIS)

    The first transmission electron microscope observations of radiation damage produced in Cu3Au by 40Ar ions with an energy of 44 MeV per nucleon, reveal in the region of dominant electronic stopping, the occurrence of very large displacement cascades, often divided into subcascades. The cascade density as well as size distribution is well accounted for, assuming they are produced by primary knocked atoms ejected from their lattice site by Rutherford scattering of the incident Ar ions. The total cross section for point defect production is estimated to be of the order of 106 barns in this region

  17. Clustering Effects Under Irradiation in Fe-0.1%Cu Alloy : An Atomic Scale Investigation with the Tomographic Atom Probe

    OpenAIRE

    Pareige, P.; Welzel, S; Auger, P.

    1996-01-01

    In order to understand the effect of displacement cascades on the evolution of the microstructure of ferritic low copper supersaturated materials, analyses by 3D atomic tomography of neutron, electron and self ion irradiated Fe-0.1%Cu, were performed. This alloy was chosen because of its low copper concentration, close to that of french pressure vessel steels. The comparison of the microstructure evolutions in these irradiated specimens reveals the appearance of tiny copper "clusters" or "agg...

  18. Atoms confined in a penetrable potential: effect of the atom position on the electric and magnetic responses

    Energy Technology Data Exchange (ETDEWEB)

    Acosta Coden, Diego S; Gomez, Sergio S; Romero, Rodolfo H, E-mail: rhromero@exa.unne.edu.ar [Instituto de Modelado e Innovacion Tecnologica, CONICET and Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Avenida Libertad 5500 (3400) Corrientes (Argentina)

    2011-02-14

    We report results of the calculation of polarizability and the nuclear magnetic shielding tensors of two-electron atoms confined within an attractive Gaussian potential well. The electric and magnetic responses are obtained within the random phase approximation (RPA) of the polarization propagator. The influence of the depth and range of the potential on the electronic structure is also studied. The dependence of the parallel (along the displacement) and perpendicular components of the polarizability and shielding tensors on the distance of the atom to the centre of the well is calculated and rationalized as a dissociation-type process of the artificial diatomic molecule formed between the Coulomb and the well potentials.

  19. Viscous Flow with Large Fluid-Fluid Interface Displacement

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz; Hassager, Ole; Saasen, Arild

    1998-01-01

    The arbitrary Lagrange-Euler (ALE) kinematic description has been implemented in a 3D transient finite element program to simulate multiple fluid flows with fluid-fluid interface or surface displacements. The description of fluid interfaces includes variable interfacial tension, and the formulati...

  20. Mining Induced Displacement and Mental Health: A Call for Action

    Science.gov (United States)

    Goessling, Kristen P.

    2010-01-01

    India is a country of unparalleled diversity within both the cultural and ecological spheres of life. This paper examines the author's experience exploring and inquiring into the mental health implications of mining and mining induced displacement within several Adivasi (tribal) communities in Andhra Pradesh, India. Through collaboration with…

  1. Temporal Displacement of Environmental Crime : Evidence from Marine Oil Pollution

    NARCIS (Netherlands)

    Vollaard, Ben

    2015-01-01

    The probability of conviction commonly varies across different circumstances due to imperfect monitoring. Evidence of whether and how offenders exploit gaps in monitoring provides insight into the process by which deterrence is produced. We present an empirical test of temporal displacement of illeg

  2. Coulomb displacement energies between analog levels for 44 < = A < = 239

    International Nuclear Information System (INIS)

    Experimental Coulomb displacement energie ΔEsub(C) between isobaric analog levels are tabulated for 44 <- A <- 239, extending recent work in which similar data were presented for 3 <- A <- 45. An overall parametrization in anti-Z/A sup(1/3) and uniform radius parameters rsub(o) are given

  3. Whose Community Is This? Mathematics of Neighborhood Displacement

    Science.gov (United States)

    Gutstein, Eric

    2013-01-01

    Displacement was part of students' realities--gentrification in North Lawndale (a Chicago community), deportation in Little Village, and foreclosures in both. The author started the unit in his 12th-grade "math for social justice" class by telling the story (with family permission) of Carmen, a student in his class. Her grandmother paid off her…

  4. New aspects in the pathogenesis of abomasal displacement.

    Science.gov (United States)

    Doll, Klaus; Sickinger, Marlene; Seeger, Torsten

    2009-08-01

    Impaired abomasal motility and an increased accumulation of gas are prerequisites for displacement of the abomasum in the cow. Predisposing factors are the breed (e.g. Holstein-Friesian, Simmental-Red-Holstein cross breeds and Guernsey), genetic background, twin pregnancy, first weeks of lactation, metabolic disorders (ketosis, increased lipomobilisation, insulin resistance), high-concentrate and low-fibre diets, as well as other concomitant diseases, such as endometritis, mastitis and claw disorders. There does not appear to be a strong correlation between increased milk yield or endotoxaemia and abomasal displacement. Recent studies have focused on possible functional disorders of the enteric nervous system within the abomasal wall, since cattle with abomasal displacement have an increased activity of neuronal nitric oxide synthase, as well as decreased acetylcholine sensitivity. In addition, there appear to be significant differences between breeds in the levels of the neurotransmitters substance P (SP) and vasoactive intestinal peptide (VIP) in the abomasal wall. For example, SP (stimulatory) was significantly less in German Holsteins in comparison to the German Fleckvieh, whereas VIP (inhibitory) was markedly increased. These risk factors may explain why Holstein cows are more susceptible to abomasal displacement than other breeds. PMID:18397836

  5. GPR monitoring of oil displacement - A laboratory study

    NARCIS (Netherlands)

    Miorali, M.; Slob, E.C.; Arts, R.J.

    2011-01-01

    In this paper we present laboratory experiments where we address the Ground Penetrating Radar (GPR) capability of monitoring oil displacement processes in porous media. This has significant applications in near-subsurface environments where remediation of contaminant such as oil-derived liquids is c

  6. The subtraction of mutually displaced Gaussian Schell-model beams

    Science.gov (United States)

    de Sande, J. Carlos G.; Santarsiero, Massimo; Piquero, Gemma; Gori, Franco

    2015-12-01

    Using recently derived results about the difference of two cross-spectral densities, we consider a source whose correlation function is the difference of two mutually displaced Gaussian Schell-model cross-spectral densities. We examine the main features of this new cross-spectral density in terms of coherence and intensity distribution, both across the source plane and after free propagation.

  7. A High-Precision Capacitive Sensor System for Displacement Measurements

    NARCIS (Netherlands)

    Yang, R.

    2015-01-01

    This thesis presents the theory, design and qualification of a precision capacitive sensor system for displacement measurement that require high resolution, high precision and simultaneously, low power consumption. The challenge to achieve the required performance has been taken care at both mechani

  8. Effect of displacement on resistance and capacitance of polyaniline film

    Institute of Scientific and Technical Information of China (English)

    Khasan Sanginovich Karimov; Muhammad Tariq Saeed; Fazal Ahmad Khalid; Syed Abdul Moiz

    2011-01-01

    This paper investigates the properties of displacement sensors based on polyaniline(PANI)films. About 1 wt% of PANI micropowder is mixed and stirred in a solution of 90 wt% water and 10 wt% alcohol at room temperature. The films of PANI are deposited from solution by drop-casting on Ag electrodes, which are preliminary deposited on glass substrates. The thicknesses of the PANI films are in the range of 20 jun-80 p.m. A displacement sensor with polyaniline film as an active material is designed and fabricated. The investigations showed that, on average, the AC resistance of the sensor decreases by 2 times and the capacitance accordingly increases by 1.6 times as the displacement changes in the range of 0 mm-0.5 mm. The polyaniline is the only active material of the displacement sensor. The resistance and capacitance of the PANI changes under the pressure of spring and elastic rubber, and this pressure is created by the downward movement of the micrometer.

  9. Lumped impulses, discrete displacements and a moving load analysis

    NARCIS (Netherlands)

    Kok, A.W.M.

    1997-01-01

    Finite element models are usually presented as relations between lumped forces and discrete displacements. Mostly finite element models are found by the elaboration of the method of the virtual work - which is a special case of the Galerkin's variational principle -. By application of Galerkin's var

  10. Character displacement in the fighting colours of Hetaerina damselflies.

    Science.gov (United States)

    Anderson, Christopher N; Grether, Gregory F

    2010-12-01

    Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a pattern of character displacement (divergence in sympatry). A geographical survey of four Hetaerina damselfly species in Mexico and Texas showed evidence for character displacement in both species pairs that regularly occurs sympatrically. Hetaerina titia, a species that typically has large black wing spots and small red wing spots, shifted to having even larger black spots and smaller red wing spots at sites where a congener with large red wing spots is numerically dominant (Hetaerina americana or Hetaerina occisa). Hetaerina americana showed the reverse pattern, shifting towards larger red wing spots where H. titia is numerically dominant. This pattern is consistent with the process of agonistic character displacement, but the ontogenetic basis of the shift remains to be demonstrated. PMID:20591870

  11. Finding small displacements of recorded speckle patterns: revisited

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Jakobsen, Michael Linde; Chakrabarti, Maumita;

    2015-01-01

    An analytical expression for the bias effect in digital speckle correlation is derived based on a Gaussian approximation of the spatial pixel size and array extent. The evaluation is carried out having assumed an incident speckle field. The analysis is focused on speckle displacements in the orde...

  12. Effect of displacement on resistance and capacitance of polyaniline film

    Science.gov (United States)

    Khasan Sanginovich, Karimov; Muhammad Tariq, Saeed; Fazal, Ahmad Khalid; Syed, Abdul Moiz

    2011-04-01

    This paper investigates the properties of displacement sensors based on polyaniline (PANI) films. About 1 wt% of PANI micropowder is mixed and stirred in a solution of 90 wt% water and 10 wt% alcohol at room temperature. The films of PANI are deposited from solution by drop-casting on Ag electrodes, which are preliminary deposited on glass substrates. The thicknesses of the PANI films are in the range of 20 μm-80 μm. A displacement sensor with polyaniline film as an active material is designed and fabricated. The investigations showed that, on average, the AC resistance of the sensor decreases by 2 times and the capacitance accordingly increases by 1.6 times as the displacement changes in the range of 0 mm-0.5 mm. The polyaniline is the only active material of the displacement sensor. The resistance and capacitance of the PANI changes under the pressure of spring and elastic rubber, and this pressure is created by the downward movement of the micrometer.

  13. Omasal dilation and displacement in 4 Holstein dairy cows

    OpenAIRE

    Bicalho, Rodrigo C.; Mayers, Heather M.; Cheong, Soon Hon; Rosa, Brielle V.; Guard, Charles L.

    2009-01-01

    Cases of omasal dilation and displacement in 4 dairy cows are described. The disease was initially diagnosed by a combination of history and clinical signs that included right-sided abdominal distension, rectal palpation, and decreased milk production. The condition was confirmed by laparotomy or necropsy.

  14. Reliability of Structural Systems with regard to Permanent Displacements

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    , for multi-degrees-of-freedom systems very little work (with practical relevance) has been done. For steel jacket platforms subjected to wave, wind and current loads with specified main directions three methods to estimate the permanent displacements during a single storm are proposed, namely: - a...

  15. Potential displacement of petroleum imports by solar energy technologies

    Energy Technology Data Exchange (ETDEWEB)

    DeLeon, P.; Jackson, B.L.; McNown, R.F.; Mahrenholz, G.J.

    1980-05-01

    The United States currently imports close to half of its petroleum requirements. This report delineates the economic, social, and political costs of such a foreign oil dependency. These costs are often intangible, but combined they clearly constitute a greater price for imported petroleum than the strictly economic cost. If we can assume that imported oil imposes significant socioeconomic costs upon the American economy and society, one way to reduce these costs is to develop alternative, domestic energy sources - such as solar energy technologies - which can displace foreign petroleum. The second half of this report estimates that by the year 2000, solar energy technologies can displace 3.6 quads of petroleum. This figure includes solar energy applications in utilities, industrial and agricultural process heat, and transportation. The estimate can be treated as a lower bound; if the United States were to achieve the proposed goal of 20 quads by 2000, the amount of displaced oil probably would be greater. Although all the displaced oil would not be imported, the reduction in imported petroleum would relieve many of the conditions that increase the present cost of foreign oil to the American consumer.

  16. Displacive processes in systems with bcc patent lattice

    Czech Academy of Sciences Publication Activity Database

    Paidar, Václav

    2011-01-01

    Roč. 56, č. 6 (2011), s. 841-851. ISSN 0079-6425 R&D Projects: GA AV ČR IAA100100920 Institutional research plan: CEZ:AV0Z10100520 Keywords : diffusionless phase transformations * displacive processes * gamma surfaces Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 18.216, year: 2011

  17. Numerical and experimental study of hydrostatic displacement machine

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Mørk; Hansen, Michael; Mouritsen, Ole Ø.

    2012-01-01

    This paper presents a simulation tool to determine the structural deflections and corresponding leakage flow in a hydrostatic displacement motor. The simulation tool is applied to a new motor principle that is categorized as an extreme low-speed high-torque motor with dimensions that calls for...

  18. Displacement of Monolithic Rubble-Mound Breakwater Crown-Walls

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke;

    2012-01-01

    studies on caisson breakwaters, but correction terms are suggested in the present paper to obtain almost equal measured and estimated displacements. This is of great practical importance since many existing rubble-mound crown-walls are subjected to increasing wave loads due to rising sea water level from...

  19. Displacements analysis of self-excited vibrations in turning

    CERN Document Server

    Bisu, Claudiu-Florinel; Gérard, Alain; K'Nevez, Jean-Yves; 10.1007/s00170-08-1815-8

    2009-01-01

    The actual research deals with determining by a new protocol the necessary parameters considering a three-dimensional model to simulate in a realistic way the turning process on machine tool. This paper is dedicated to the experimental displacements analysis of the block tool / block workpiece with self-excited vibrations. In connexion with turning process, the self-excited vibrations domain is obtained starting from spectra of two accelerometers. The existence of a displacements plane attached to the tool edge point is revealed. This plane proves to be inclined compared to the machines tool axes. We establish that the tool tip point describes an ellipse. This ellipse is very small and can be considered as a small straight line segment for the stable cutting process (without vibrations). In unstable mode (with vibrations) the ellipse of displacements is really more visible. A difference in phase occurs between the tool tip displacements on the radial direction and on the cutting one. The feed motion direction...

  20. Plane Stratified Flow in a Room Ventilated by Displacement Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm; Nickel, J.; Baron, D. J. G.

    2004-01-01

    The air movement in the occupied zone of a room ventilated by displacement ventilation exists as a stratified flow along the floor. This flow can be radial or plane according to the number of wall-mounted diffusers and the room geometry. The paper addresses the situations where plane flow is obta...... flow. The thickness and the velocity are functions of the Archimedes number....